4,141 results on '"Buck, A."'
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2. There Is Another Choice: An Exploration of Integrating Formative Assessment in a Chinese High School Chemistry Classroom through Collaborative Action Research
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Yin, Xinying and Buck, Gayle A.
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This study explored integrating formative assessment to a Chinese high school chemistry classroom, where the extremely high-stakes testing and Confucian-heritage culture constituted a particular context, through a collaborative action research. One researcher worked with a high school chemistry teacher in China to integrate formative assessment into his teaching with 54 students in one of his classes. Data resources included transcripts from planning sessions, lesson plans, teacher interviews, classroom observations, student work, student interviews and surveys. The findings of this study revealed that as the teacher allowed his original views about students' learning and assessment tasks to be challenged by the students' learning, his teaching practice and understandings of formative assessment were transformed. Students' learning experience was also examined in the formative assessment process. The potentials and challenges of integrating formative assessment in the Chinese high school science classroom are discussed. This study indicated that formative assessment is promising to implement in Chinese high school science classrooms to enhance students' learning and meet the imperative needs for high-stakes exam preparation as well; and writing formative assessment tasks are favorable in this particular socio-cultural context. Further, this study suggested that facilitating in-service science teachers to integrate formative assessment through collaborative action research is a powerful professional development on improving teaching and learning under the highly constraint context.
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- 2015
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3. Characterizing the Level of Inquiry in the Undergraduate Laboratory
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Buck, Laura B., Bretz, Stacey Lowery, and Towns, Marcy H.
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Discrepancies abound in use of the word "inquiry." In this paper, the authors propose a quantitative rubric designed to characterize the level of inquiry in laboratory activities and laboratory curricula. They do not wish to answer the question, "What is inquiry?" but rather, provide a tool for identifying its varying degrees of student independence. (Contains 3 tables.)
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- 2008
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4. Modeling Protein Domain Function
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Baker, William P., Jones, Carleton 'Buck', and Hull, Elizabeth
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This simple but effective laboratory exercise helps students understand the concept of protein domain function. They use foam beads, Styrofoam craft balls, and pipe cleaners to explore how domains within protein active sites interact to form a functional protein. The activity allows students to gain content mastery and an understanding of the vital role of proteins within cells. The exercise also enables teachers to assess student performance on several levels. (Contains 2 figures.)
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- 2007
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5. Nanophytomedicines as Therapeutic Agents for Parkinson’s Disease
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Jessica Burns, Amy Claire Buck, Sarah D’ Souza, Admire Dube, and Soraya Bardien
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Chemistry ,QD1-999 - Published
- 2023
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6. Temperature Behavior in Headlights: A Comparative Analysis between Battery Electric Vehicles and Internal Combustion Engine Vehicles
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Tabea Schlürscheid, Tran Quoc Khanh, Alexander Buck, and Stefan Weber
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road environments ,headlight ,temperature behavior ,battery electric vehicles ,internal combustion engine vehicles ,Technology ,Engineering (General). Civil engineering (General) ,TA1-2040 ,Biology (General) ,QH301-705.5 ,Physics ,QC1-999 ,Chemistry ,QD1-999 - Abstract
In the context of a global shift towards renewable energies and climate change mitigation, the market for electric vehicles has experienced a remarkable upswing, with battery electric vehicles (BEVs) leading this transformative wave. The appeal of BEVs lies in their ability to significantly curtail CO2 emissions by supplanting the traditional internal combustion engine (ICE) with an electric motor. This pivotal change in vehicular technology extends its influence to various subsystems, including automotive lighting. Headlights are particularly sensitive to the thermal environment they operate in, which can profoundly affect their functionality and durability. The removal of an ICE in BEVs typically results in a reduction in heat exposure to headlight components, prompting a potential reevaluation of their design. This article presents a comprehensive analysis of temperature distributions within headlight units, comparing BEVs and ICE vehicles. The study encompasses a robust dataset of nearly 30,000 vehicles from around the globe, taking into account the impact of ambient temperature on headlight operation. The investigation delineates the distinct thermal behaviors of the two vehicle categories and offers strategic recommendations for conceptual modifications of headlights in BEVs. These adjustments are aimed at enhancing headlight efficacy, prolonging lifespan, and furthering the sustainability objectives of electric mobility.
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- 2024
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7. Development of novel cytoprotective small compounds inhibiting mitochondria-dependent cell death
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Mieko Matsuyama, Joseph T. Ortega, Yuri Fedorov, Jonah Scott-McKean, Jeannie Muller-Greven, Matthias Buck, Drew Adams, Beata Jastrzebska, William Greenlee, and Shigemi Matsuyama
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Chemistry ,Cellular physiology ,Cell biology ,Science - Abstract
Summary: We identified cytoprotective small molecules (CSMs) by a cell-based high-throughput screening of Bax inhibitors. Through a medicinal chemistry program, M109S was developed, which is orally bioactive and penetrates the blood-brain/retina barriers. M109S protected retinal cells in ocular disease mouse models. M109S directly interacted with Bax and inhibited the conformational change and mitochondrial translocation of Bax. M109S inhibited ABT-737-induced apoptosis both in Bax-only and Bak-only mouse embryonic fibroblasts. M109S also inhibited apoptosis induced by staurosporine, etoposide, and obatoclax. M109S decreased maximal mitochondrial oxygen consumption rate and reactive oxygen species production, whereas it increased glycolysis. These effects on cellular metabolism may contribute to the cytoprotective activity of M109S. M109S is a novel small molecule protecting cells from mitochondria-dependent apoptosis both in vitro and in vivo. M109S has the potential to become a research tool for studying cell death mechanisms and to develop therapeutics targeting mitochondria-dependent cell death pathway.
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- 2023
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8. Proteomic Changes in the Monolayer and Spheroid Melanoma Cell Models of Acquired Resistance to BRAF and MEK1/2 Inhibitors
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Ramon Martinez, Weiliang Huang, Heather Buck, Samantha Rea, Amy E. Defnet, Maureen A. Kane, and Paul Shapiro
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Chemistry ,QD1-999 - Published
- 2022
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9. Aquatic Analysis.
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Mauro, Nicole and Buck-Bernard, Jennifer
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Describes a yearlong project that involves biology students in monitoring water quality. Includes details of the awareness phase, action phase, and presentation phase. Discusses student reaction to the project. (DDR)
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- 1998
10. Improvement of DNA Vector Delivery of DOTAP Lipoplexes by Short-Chain Aminolipids
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Jonas Buck, Dennis Mueller, Ute Mettal, Miriam Ackermann, Hiu Man Grisch-Chan, Beat Thöny, Andreas Zumbuehl, Jörg Huwyler, and Dominik Witzigmann
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Chemistry ,QD1-999 - Published
- 2020
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11. Adsorption-Induced Expansion of Graphene Oxide Frameworks: Observation by in Situ Neutron Diffraction
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Joseph C. Schaeperkoetter, Matthew J. Connolly, Zachary N. Buck, Haskell Taub, Helmut Kaiser, and Carlos Wexler
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Chemistry ,QD1-999 - Published
- 2019
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12. Atmospheric processing of iron in mineral and combustion aerosols: development of an intermediate-complexity mechanism suitable for Earth system models
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R. A. Scanza, D. S. Hamilton, C. Perez Garcia-Pando, C. Buck, A. Baker, and N. M. Mahowald
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Physics ,QC1-999 ,Chemistry ,QD1-999 - Abstract
Atmospheric processing of iron in dust and combustion aerosols is simulated using an intermediate-complexity soluble iron mechanism designed for Earth system models. The solubilization mechanism includes both a dependence on aerosol water pH and in-cloud oxalic acid. The simulations of size-resolved total, soluble and fractional iron solubility indicate that this mechanism captures many but not all of the features seen from cruise observations of labile iron. The primary objective was to determine the extent to which our solubility scheme could adequately match observations of fractional iron solubility. We define a semi-quantitative metric as the model mean at points with observations divided by the observational mean (MMO). The model is in reasonable agreement with observations of fractional iron solubility with an MMO of 0.86. Several sensitivity studies are performed to ascertain the degree of complexity needed to match observations; including the oxalic acid enhancement is necessary, while different parameterizations for calculating model oxalate concentrations are less important. The percent change in soluble iron deposition between the reference case (REF) and the simulation with acidic processing alone is 63.8 %, which is consistent with previous studies. Upon deposition to global oceans, global mean combustion iron solubility to total fractional iron solubility is 8.2 %; however, the contribution of fractional iron solubility from combustion sources to ocean basins below 15° S is approximately 50 %. We conclude that, in many remote ocean regions, sources of iron from combustion and dust aerosols are equally important. Our estimates of changes in deposition of soluble iron to the ocean since preindustrial climate conditions suggest roughly a doubling due to a combination of higher dust and combustion iron emissions along with more efficient atmospheric processing.
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- 2018
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13. A 'Tug of War' Maintains a Dynamic Protein–Membrane Complex: Molecular Dynamics Simulations of C‑Raf RBD-CRD Bound to K‑Ras4B at an Anionic Membrane
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Zhen-Lu Li, Priyanka Prakash, and Matthias Buck
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Chemistry ,QD1-999 - Published
- 2018
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14. Four-Dimensional Investigation of Gravel Beach Ridge Accretion and 50 Years of Beach Recharge at Dungeness, UK, Using Historic Images, GPR and Lidar (HIGL)
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Charlie S. Bristow, Lucy Buck, and Maria Inggrid
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shingle ,beach recharge ,beach nourishment ,sediment budget ,lidar ,ground-penetrating radar ,Technology ,Engineering (General). Civil engineering (General) ,TA1-2040 ,Biology (General) ,QH301-705.5 ,Physics ,QC1-999 ,Chemistry ,QD1-999 - Abstract
Dungeness is a cuspate foreland on the south coast of England that is the largest shingle feature in Europe and includes hundreds of beach ridges. It is also the location of two nuclear power stations that were constructed in the 1960s. The dominant southwest waves cause longshore drift from west to east, eroding the southwest side of Dungeness, accompanied by accretion on the east side. A record of this eastward movement and sediment accretion is preserved by the shingle beach ridges. The power stations are located on the eroding southwestern side of the ness, and a system of beach recharge has been used to move shingle from the downdrift, east-facing shore to the updrift, southwest-facing shore to protect the power stations from coastal erosion. We use a novel combination of historic images, ground-penetrating radar (GPR), and Lidar (HIGL) to investigate accretion and beach ridges at Dungeness during the past 80 years. We report changes in accretion along the coast and use GPR to determine the thickness of beach gravels. The amount of accretion, represented by the width of the backshore, decreases downdrift from south to north. The number of beach ridges preserved also decreases from south to north. By combining the shingle thickness from GPR with elevation data from Lidar surveys and records of beach accretion measured from aerial images, we estimate the volume and mass of gravel that has accumulated at Dungeness. Historic rates of beach accretion are similar to recent rates, suggesting that the 55 years of beach recharge have had little impact on the longer-term accretion downdrift.
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- 2021
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15. A proteome‐scale analysis of vertebrate protein amino acid occurrence: Thermoadaptation shows a correlation with protein solvation but less so with dynamics
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Matthias Buck and Zhenlu Li
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chemistry.chemical_classification ,Proteome ,biology ,Protein dynamics ,Allosteric regulation ,Vertebrate ,Protein superfamily ,Biochemistry ,Amino acid ,Cold Temperature ,Poikilotherm ,chemistry ,Structural Biology ,biology.animal ,Vertebrates ,Animals ,Amino Acid Sequence ,Amino Acids ,Peptide sequence ,Molecular Biology - Abstract
Despite differences in behaviors and living conditions, vertebrate organisms share the great majority of proteins, often with subtle differences in amino acid sequence. Here, we present a simple way to analyze the difference in amino acid occurrence by comparing highly homologous proteins on a sub-proteome level between several vertebrate model organisms. Specifically, we use this method to identify a pattern of amino acid conservation as well as a shift in amino acid occurrence between homeotherms (warm-blooded species) and poikilotherms (cold-blooded species). Importantly, this general analysis and a specific example further establish a correlation, if not likely connection between the thermoadaptation of protein sequences and two of their physical features: a possible change in their protein dynamics and, even more strongly, in their solvation. For poikilotherms, such as frog and fish, the lower body temperature is expected to increase the association of proteins due to a decrease in protein internal dynamics. In order to prevent overly-sticky protein association at low temperatures, the use of amino acids suggests that poikilotherms enhance the solvation of their proteins by favoring polar groups on their protein’s surface. This feature appears to dominate over possible changes in dynamics. The results suggest that a general trend for amino acid choice is part of the mechanism for thermoadaptation of vertebrate organisms at the molecular level.
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- 2022
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16. High-flux CO2-stable oxygen transport hollow fiber membranes through surface engineering
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Thomas Schiestel, O. Bunjaku, F. Buck, and Juergen Caro
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Materials science ,Diffusion ,Oxygen transport ,chemistry.chemical_element ,Surface engineering ,Permeation ,Dip-coating ,Oxygen ,Membrane ,Chemical engineering ,chemistry ,Materials Chemistry ,Ceramics and Composites ,Fiber - Abstract
The influences of bulk diffusion and surface exchange on oxygen transport of (La0.6Ca0.4)(Co0.8Fe0.2)O3-δ (LCCF) hollow fiber membranes were investigated. As an outcome, two strategies for increasing the oxygen permeation were pursued. First, porous LCCF hollow fibers as support were coated with a 22 μm dense LCCF separation layer through dip coating and co-sintering. The oxygen permeation of the porous fiber with dense layer reached up to 5.10 mL min−1 cm-2 at 1000 °C in a 50 % CO2 atmosphere. Second, surface etching of dense LCCF hollow fibers with H2SO4 was applied. The surface etching of both inner and outer surfaces leads to a permeation improvement up to 86.0 %. This finding implies that the surface exchange reaction plays a key role in oxygen transport through LCCF hollow fibers. A good long-term (>250 h) stability of the asymmetric hollow fiber in a 50 % CO2 atmosphere was found at 900 °C.
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- 2022
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17. A guide to accelerated direct digital counting of single nucleic acid molecules by FRET-based intramolecular kinetic fingerprinting
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Shankar Mandal, Nils G. Walter, Alexander Johnson-Buck, and Kunal Khanna
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Detection limit ,0303 health sciences ,Total internal reflection fluorescence microscope ,Chemistry ,030302 biochemistry & molecular biology ,Mutant ,Fluorescence ,Article ,General Biochemistry, Genetics and Molecular Biology ,Kinetics ,MicroRNAs ,03 medical and health sciences ,Förster resonance energy transfer ,Limit of Detection ,Nucleic Acids ,Intramolecular force ,Fluorescence Resonance Energy Transfer ,Nucleic acid ,Biophysics ,Nanotechnology ,Molecule ,Molecular Biology ,030304 developmental biology - Abstract
Cell-free nucleic acids (cfNAs) such as short non-coding microRNA (miRNA) and circulating tumor DNA (ctDNA) that reside in bodily fluids have emerged as potential cancer biomarkers. Methods for the rapid, highly specific, and sensitive monitoring of cfNAs in biofluids have, therefore, become increasingly attractive as clinical diagnosis tools. As a next generation technology, we provide a practical guide for an amplification-free, single molecule Forster resonance energy transfer (smFRET)-based kinetic fingerprinting approach termed intramolecular single molecule recognition through equilibrium Poisson sampling, or iSiMREPS, for the rapid detection and counting of miRNA and mutant ctDNA with virtually unlimited specificity and single molecule sensitivity. iSiMREPS utilizes a pair of fluorescent detection probes, wherein one probe immobilizes the target molecules on the surface, and the other probe transiently and reversibly binds to the target to generate characteristic time-resolved fingerprints as smFRET signal that are detected in a total internal reflection fluorescence microscope. Analysis of these kinetic fingerprints enables near-perfect discrimination between specific binding to target molecules and nonspecific background binding. By accelerating kinetic fingerprinting using the denaturant formamide and reducing background signals by removing target-less probes from the surface via toehold-mediated strand displacement, iSiMREPS has been demonstrated to count miR-141 and EGFR exon 19 deletion ctDNA molecules with a limit of detection (LOD) of ~1 and 3 fM, respectively, as well as mutant allele fractions as low as 0.0001%, during a standard acquisition time of only ~10 s per field of view. In this review, we provide a detailed roadmap for implementing iSiMREPS more broadly in research and clinical diagnostics, combining rapid analysis, high specificity, and high sensitivity.
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- 2022
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18. Evidence for virus-mediated oncogenesis in bladder cancers arising in solid organ transplant recipients
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Kelly J. Yu, Michael Dean, Cyllene R. Morris, Brenda Y. Hernandez, Ajay K. Israni, Iona Cheng, Thomas C. Tucker, Petra Lenz, Shehnaz K. Hussain, David Peterson, Charles F. Lynch, Yelena G. Golubeva, Gabriel J. Starrett, Lou Gonsalves, Mary L Piaskowski, Christopher B. Buck, Ludmila Prokunina-Olsson, Eric A. Engels, Reuben S. Harris, and Paul S. Meltzer
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Mutation ,education.field_of_study ,Bladder cancer ,General Immunology and Microbiology ,General Neuroscience ,Population ,Aristolochic acid ,General Medicine ,Biology ,medicine.disease ,medicine.disease_cause ,Virus ,General Biochemistry, Genetics and Molecular Biology ,chemistry.chemical_compound ,chemistry ,Host chromosome ,medicine ,Cancer research ,Carcinogenesis ,education ,Oncovirus - Abstract
A small percentage of bladder cancers in the general population have been found to harbor DNA viruses. In contrast, up to 25% of tumors of solid organ transplant recipients, who are at an increased risk of developing bladder cancer and have overall poorer outcome, harbor BK polyomavirus (BKPyV). To better understand the biology of the tumors and the mechanisms of carcinogenesis from potential oncoviruses, we performed whole genome and transcriptome sequencing on bladder cancer specimens from 43 transplant patients. Nearly half of tumors from this patient population contained viral sequences. The most common were from BKPyV (N=9, 21%), JC polyomavirus (N=7, 16%), carcinogenic human papillomaviruses (N=3, 7%), and torque teno viruses (N=5, 12%). Immunohistochemistry revealed variable Large T antigen expression in BKPyV-positive tumors ranging from 100% positive staining of tumor tissue to less than 1%. In most cases of BKPyV-positive tumors, the viral genome appeared to be clonally integrated into the host chromosome consistent with microhomology-mediated end joining and coincided with focal amplifications of the tumor genome similar to other virus-mediated cancers. Significant changes in host gene expression consistent with the functions of BKPyV Large T antigen were also observed in these tumors. Lastly, we identified four mutation signatures in our cases with those attributable to APOBEC3 and SBS5 being the most abundant. Mutation signatures associated with the antiviral drug, ganciclovir, and aristolochic acid, a nephrotoxic compound found in some herbal medicines, were also observed. The results suggest multiple pathways to carcinogenesis in solid organ transplant recipients with a large fraction being virus-associated.Author SummarySolid organ transplant recipients are at a significantly increases risk for developing bladder cancer compared to the general population, suggesting a potential infectious origin to these tumors. This study identifies that BK polyomavirus, JC polyomavirus, human papillomaviruses, and anelloviruses are commonly found in bladder tumors of solid organ transplant recipients. In most cases when detected, BK polyomavirus is integrated into the tumor genome and associates with genomic structural changes and distinct gene expression through the activity of viral oncogenes. Additionally, mutational signature analysis suggests that a subset of tumors of solid organ transplant recipients develop through distinct mutagenic processes compared to the general population. Together these results indicate multiple distinct mechanisms of carcinogenesis in bladder cancers of solid organ transplant recipients that may have implications for prevention, treatment, and outcome.
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- 2023
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19. Key Aroma Compounds in Two Bavarian Gins
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Nina Buck, Tina Goblirsch, Jonathan Beauchamp, and Eva Ortner
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aroma ,botanicals ,gas chromatography-olfactometry (GC-O) ,gin ,juniper ,odor activity value ,Technology ,Engineering (General). Civil engineering (General) ,TA1-2040 ,Biology (General) ,QH301-705.5 ,Physics ,QC1-999 ,Chemistry ,QD1-999 - Abstract
The characteristic, dominant flavor of gin is juniper, often within a complex aroma of other botanicals. The present study examined two gins from a distillery in the German state of Bavaria; one produced with 50 individual botanicals, the other with 15. The study focused on characterizing the aroma profiles and identifying the key aroma-active compounds of the gins. Comparative sensory evaluations of the gins revealed marked differences in their aroma profiles, with the botanical-rich gin exhibiting more citrusy, orangey and fruity notes than the gin containing fewer botanicals. Instrumental analyses by gas chromatography-mass spectrometry/olfactometry (GC-MS/O) using aroma extract dilution assays (AEDA) identified terpenes as the dominant key aroma compounds, specifically limonene, 1,8-cineole, linalool, estragole and trans-anethole, with additional contributions from aldehydes, such as nonanal, and phenylpropanoids, such as eugenol and estragole. Selected compounds were quantified using stir-bar sorptive extraction (SBSE) and stabile isotope dilution analysis (SIDA) with GC-MS analysis. Further, odor thresholds and corresponding odor activity values (OAVs) of these compounds were calculated, with linalool exhibiting the highest OAV in both gins. The present analyses revealed how different botanicals alter the concentrations of key aroma compound constituents and elicit a shift in the overall aroma profile of the final spirit.
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- 2020
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20. Transparent, Pliable, Antimicrobial Hydrogels for Ocular Wound Dressings
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Tao Liu, Eleonore C.L. Bolle, Traian V. Chirila, Marion Buck, Daniel Jonas, Shuko Suzuki, Tai Smith, V. Prasad Shastri, Tim R. Dargaville, and Aurelien Forget
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hydrogel ,wound dressing ,antimicrobial ,Technology ,Engineering (General). Civil engineering (General) ,TA1-2040 ,Biology (General) ,QH301-705.5 ,Physics ,QC1-999 ,Chemistry ,QD1-999 - Abstract
Following ocular surgery, dressings are commonly applied to the surgical wound. These dressings need to combine medical properties with ease of use while maintaining comfort for the patient. For the ocular area, this means that the dressings need to act as a microbial barrier, allow good conformability to the contours of the eye, and provide evaporative cooling to the inflamed area. Furthermore, the dressings should be transparent to allow for the inspection of the wound site by healthcare professionals without the need for removal. In this paper, we investigate a blend of native agarose (NA) and carboxylated agarose (CA) for producing elastic hydrogels with high water content that can be supplemented with antibiotics. It was found that in comparison to pure agarose hydrogels, the NA hydrogels blended with CA had a reduced Young’s modulus, reduced evaporation rate when exposed to air, and accelerated release rate of antimicrobial agents, whilst maintaining the same degree of transparency. By altering the formulation from 2 wt.% pure NA to 1 wt.% NA blended with 1 wt.% CA, we were able to observe an approximately 55% reduction in Young’s modulus, 25% reduction in evaporation rate, as well as a significant acceleration in the release rate of cefazolin and doxycycline, making this hydrogel blend a potential material for topical treatment applications.
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- 2020
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21. Element-Specific Magnetization Dynamics of Complex Magnetic Systems Probed by Ultrafast Magneto-Optical Spectroscopy
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Clemens von Korff Schmising, Felix Willems, Sangeeta Sharma, Kelvin Yao, Martin Borchert, Martin Hennecke, Daniel Schick, Ilie Radu, Christian Strüber, Dieter W. Engel, Vishal Shokeen, Jens Buck, Kai Bagschik, Jens Viefhaus, Gregor Hartmann, Bastian Manschwetus, Soeren Grunewald, Stefan Düsterer, Emmanuelle Jal, Boris Vodungbo, Jan Lüning, and Stefan Eisebitt
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ultrafast demagnetization dynamics ,transient absorption spectroscopy ,free electron laser ,high harmonic generation ,Technology ,Engineering (General). Civil engineering (General) ,TA1-2040 ,Biology (General) ,QH301-705.5 ,Physics ,QC1-999 ,Chemistry ,QD1-999 - Abstract
The vision to manipulate and control magnetism with light is driven on the one hand by fundamental questions of direct and indirect photon-spin interactions, and on the other hand by the necessity to cope with ever growing data volumes, requiring radically new approaches on how to write, read and process information. Here, we present two complementary experimental geometries to access the element-specific magnetization dynamics of complex magnetic systems via ultrafast magneto-optical spectroscopy in the extreme ultraviolet spectral range. First, we employ linearly polarized radiation of a free electron laser facility to demonstrate decoupled dynamics of the two sublattices of an FeGd alloy, a prerequisite for all-optical magnetization switching. Second, we use circularly polarized radiation generated in a laboratory-based high harmonic generation setup to show optical inter-site spin transfer in a CoPt alloy, a mechanism which only very recently has been predicted to mediate ultrafast metamagnetic phase transitions.
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- 2020
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22. Dynamic Modeling for Resilience Measurement: NATO Resilience Decision Support Model
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Jan Hodicky, Gökhan Özkan, Hilmi Özdemir, Petr Stodola, Jan Drozd, and Wayne Buck
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NATO resilience ,resilience measurement ,system dynamics ,dynamic modeling ,Technology ,Engineering (General). Civil engineering (General) ,TA1-2040 ,Biology (General) ,QH301-705.5 ,Physics ,QC1-999 ,Chemistry ,QD1-999 - Abstract
Despite its conceptual uncertainty, resilience is mostly about the measurement of capacity. Current studies confirm the importance of resilience measurement and the necessity to support policy makers with a measurement mechanism. A holistic approach considering the measurement of different resilience domains interactively and concurrently is the critical element in this endeavor. In parallel with the rise of popularity of resilience in international organizations, NATO has initiated a project with the objective to discover whether the resilience capacity of a country can be evaluated in a dynamic way via a prototype model execution. The implemented model running both baseline (without any shock) and extraordinary scenarios (with strategic shocks), clearly demonstrates its capacity to represent quantitatively the resilience related factors of a country in the complex operational environment. Moreover, the outputs of the model substantially comply with the resilience concept existing in the literature and NATO applications. One of the main strengths of the model is its almost infinite capacity to create various scenarios and make what-if analysis limited only by the current number of endogenous parameters of the model. It allows studying the secondary and the third order effects of events introduced in scenarios. The user interfaces (input and output dashboards) of the model help decision makers modify the values of selected endogenous parameters, see and compare the time-based values of the resilience factors, and doing so to evaluate risk related to the Area of Operations. Subject matter experts have validated the model and identified the main areas of improvement. The further development brings more countries to the model and implements an aggregation mechanism for output values of both resilience capacity and risk functions. The model will form the core of the NATO Resilience expert system.
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- 2020
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23. Metal(loid)s and human semen quality: The LIFE Study
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Zhen Chen, Francesca Branch, Germaine M. Buck Louis, and Melissa J. Perry
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Adult ,Chromium ,Male ,Infertility ,Population ,chemistry.chemical_element ,Toxicology ,Andrology ,Young Adult ,Semen quality ,Semen ,medicine ,Humans ,education ,Arsenic ,Metalloids ,education.field_of_study ,Cadmium ,Sperm Count ,Chemistry ,Middle Aged ,medicine.disease ,Sperm ,Metalloid ,Copper ,Selenium - Abstract
Multiple studies have demonstrated a global population-wide decline in semen quality, with sperm concentrations having fallen 50 % over the past 50 years. Several metal and metalloid (“metal(loid)”) compounds are known to have testicular toxicity, raising concerns about their contribution to rising infertility. In the male reproductive tract, metal(loid)s can reduce semen quality and disturb function both directly, by inducing tissue damage, and indirectly, by disrupting hormone production and secretion. This study assessed associations between 15 creatinine-adjusted metal(loid)s and 7 measures of semen quality among 413 reproductive-aged men recruited from 16 U.S. counties between 2005–2009. Multi-metal(loid) multivariable linear regression models estimated associations between semen quality endpoints and urinary concentrations of chromium, cobalt, copper, molybdenum, selenium, zinc, antimony, arsenic, barium, cadmium, lead, thallium, tin, tungsten, and uranium. LASSO regression was employed to select model variables and account for multicollinearity of the metal(loid)s. A positive association was observed between tin and sperm morphology (β = 4.92 p = 0.045). Chromium (β = 1.87, p = 0.003) and copper (β= −1.30, p = 0.028) were positively and negatively associated with total sperm count, respectively. With respect to DNA fragmentation, cadmium (β = 12.73, p = 0.036) was positively associated and chromium was negatively associated (β = −5.08, p = 0.001). In this cohort of U.S. population-based men, there was evidence of both positive and negative associations between specific metal(loid)s and semen quality. Additional research is needed to determine interactions between metal(loid)s within a mixture, consistent with typical human exposure, and identify sperm effects resulting from cumulative metal(loid) exposures.
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- 2021
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24. Effect of plasma atmosphere on the oxygen transport of mixed ionic and electronic conducting hollow fiber membranes
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F. Buck, K. Wiegers, Thomas Schiestel, and Andreas Schulz
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Membrane ,Materials science ,Chemical engineering ,chemistry ,General Chemical Engineering ,Oxygen transport ,chemistry.chemical_element ,Plasma ,Fiber ,Phase inversion (chemistry) ,Permeation ,Oxygen ,Perovskite (structure) - Abstract
Perovskite hollow fibers have been used to extract oxygen from different oxygen containing plasmas. The influence of the working length and the temperature on the oxygen transport of (La0.6Ca0.4)(Co0.8Fe0.2)O3-δ (LCCF) hollow fiber membranes in an air and a CO2 plasma were investigated and compared with a conventional electrically heated oven system at a similar temperature. High-quality LCCF hollow fiber membranes were prepared via phase inversion spinning and sintering. In the CO2 plasma, the feasibility of the oxygen extraction due to the CO2 splitting according to CO2 ⇄ CO + ½ O2 was studied. For an active membrane length of 0.5 cm, oxygen permeation values of 17.27 ml min−1 cm−2 in an air plasma at 0.67 kW and 4.97 ml min−1 cm−2 in a CO2 plasma at 1 kW were reached.
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- 2021
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25. Oxygen‐deficient water zones in the Baltic Sea promote uncharacterized Hg methylating microorganisms in underlying sediments
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Moritz Buck, Elias Broman, Daniel Lundin, Stefano Bonaglia, Eric Capo, Jarone Pinhassi, Andrea G. Bravo, Per O. J. Hall, Erik Björn, Francisco J. A. Nascimento, Anne L. Soerensen, Stefan Bertilsson, Agencia Estatal de Investigación (España), Swedish Research Council, Swedish Environmental Protection Agency, and European Commission
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Microorganism ,Oceanography, Hydrology, Water Resources ,010501 environmental sciences ,Aquatic Science ,Oceanography ,Microbiology ,01 natural sciences ,03 medical and health sciences ,chemistry.chemical_compound ,14. Life underwater ,Methylmercury ,030304 developmental biology ,0105 earth and related environmental sciences ,Ekologi ,0303 health sciences ,Ecology ,integumentary system ,Oxygen deficient ,Chemistry ,fungi ,Biochemistry and Molecular Biology ,food and beverages ,Biota ,Mikrobiologi ,Baltic sea ,Environmental chemistry ,Biokemi och molekylärbiologi - Abstract
12 pages, 3 figures, 2 tables, supporting information https://doi.org/10.1002/lno.11981.-- Data Availability Statement: The raw sequence data that support the findings in this study have been deposited online and can be accessed at the NCBI BioProject PRJNA531756, Human-induced expansion of oxygen-deficient zones can have dramatic impacts on marine systems and its resident biota. One example is the formation of the potent neurotoxic methylmercury (MeHg) that is mediated by microbial methylation of inorganic divalent Hg (HgII) under oxygen-deficient conditions. A negative consequence of the expansion of oxygen-deficient zones could be an increase in MeHg production due to shifts in microbial communities in favor of microorganisms methylating Hg. There is, however, limited knowledge about Hg-methylating microbes, i.e., those carrying hgc genes critical for mediating the process, from marine sediments. Here, we aim to study the presence of hgc genes and transcripts in metagenomes and metatranscriptomes from four surface sediments with contrasting concentrations of oxygen and sulfide in the Baltic Sea. We show that potential Hg methylators differed among sediments depending on redox conditions. Sediments with an oxygenated surface featured hgc-like genes and transcripts predominantly associated with uncultured Desulfobacterota (OalgD group) and Desulfobacterales (including Desulfobacula sp.) while sediments with a hypoxic-anoxic surface included hgc-carrying Verrucomicrobia, unclassified Desulfobacterales, Desulfatiglandales, and uncharacterized microbes. Our data suggest that the expansion of oxygen-deficient zones in marine systems may lead to a compositional change of Hg-methylating microbial groups in the sediments, where Hg methylators whose metabolism and biology have not yet been characterized will be promoted and expand, This work was funded by the Swedish Research Council Formas (grants 2018-01031 and 2016-00804); the Swedish Research Council (grants 2015-03717 and 2017-04422); the Swedish Environmental Protection Agency (grant NV-802-0151-18). A.G.B. acknowledges the Marie Curie Individual Fellowship (H2020-MSCA-IF-2016; project-749645). The authors acknowledge support from the National Genomics Infrastructure in Stockholm funded by Science for Life Laboratory, the Knut and Alice Wallenberg Foundation and the Swedish Research Council; SNIC/Uppsala Multidisciplinary Center for Advanced Computational Science for assistance with massively parallel sequencing and access to the UPPMAX computational infrastructure. The bioinformatic analyses were enabled by resources in project SNIC 2018-8-246 provided by the Swedish National Infrastructure for Computing (SNIC) at UPPMAX, partially funded by the Swedish Research Council through grant agreement no. 2018-05973, With the institutional support of the ‘Severo Ochoa Centre of Excellence’ accreditation (CEX2019-000928-S)
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- 2021
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26. DNA damage and repair in peripheral blood mononuclear cells after internal ex vivo irradiation of patient blood with 131I
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KR Pfestroff, Andreas Pfestroff, Andreas K. Buck, S. Schoof, Sarah Schumann, Harry Scherthan, Natalie Hasenauer, Uta Eberlein, Michael Lassmann, Markus Luster, Philipp E. Hartrampf, and Matthias Port
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ddc:615 ,Chemistry ,DNA damage ,Cell ,General Medicine ,Molecular biology ,Peripheral blood mononuclear cell ,Ionizing radiation ,medicine.anatomical_structure ,Absorbed dose ,Radionuclide therapy ,medicine ,Radiology, Nuclear Medicine and imaging ,Irradiation ,Ex vivo - Abstract
Aim The aim of this study was to provide a systematic approach to characterize DNA damage induction and repair in isolated peripheral blood mononuclear cells (PBMCs) after internal ex vivo irradiation with [131I]NaI. In this approach, we tried to mimic ex vivo the irradiation of patient blood in the first hours after radioiodine therapy. Material and methods Blood of 33 patients of two centres was collected immediately before radioiodine therapy of differentiated thyroid cancer (DTC) and split into two samples. One sample served as non-irradiated control. The second sample was exposed to ionizing radiation by adding 1 ml of [131I]NaI solution to 7 ml of blood, followed by incubation at 37 °C for 1 h. PBMCs of both samples were isolated, split in three parts each and (i) fixed in 70% ethanol and stored at − 20 °C directly (0 h) after irradiation, (ii) after 4 h and (iii) 24 h after irradiation and culture in RPMI medium. After immunofluorescence staining microscopically visible co-localizing γ-H2AX + 53BP1 foci were scored in 100 cells per sample as biomarkers for radiation-induced double-strand breaks (DSBs). Results Thirty-two of 33 blood samples could be analysed. The mean absorbed dose to the blood in all irradiated samples was 50.1 ± 2.3 mGy. For all time points (0 h, 4 h, 24 h), the average number of γ-H2AX + 53BP1 foci per cell was significantly different when compared to baseline and the other time points. The average number of radiation-induced foci (RIF) per cell after irradiation was 0.72 ± 0.16 at t = 0 h, 0.26 ± 0.09 at t = 4 h and 0.04 ± 0.09 at t = 24 h. A monoexponential fit of the mean values of the three time points provided a decay rate of 0.25 ± 0.05 h−1, which is in good agreement with data obtained from external irradiation with γ- or X-rays. Conclusion This study provides novel data about the ex vivo DSB repair in internally irradiated PBMCs of patients before radionuclide therapy. Our findings show, in a large patient sample, that efficient repair occurs after internal irradiation with 50 mGy absorbed dose, and that the induction and repair rate after 131I exposure is comparable to that of external irradiation with γ- or X-rays.
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- 2021
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27. Single-molecule mechanical fingerprinting with DNA nanoswitch calipers
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Andrew Ward, Darren Yang, Wesley P. Wong, Serkan Cabi, Elisha Krieg, Bhavik Nathwani, Prakash Shrestha, Yi Luo, Toma E. Tomov, William M. Shih, James I. MacDonald, Hans T. Bergal, and Alexander Johnson-Buck
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chemistry.chemical_classification ,Magnetic tweezers ,Materials science ,Biomolecule ,Biomedical Engineering ,Force spectroscopy ,Bioengineering ,Nanotechnology ,Condensed Matter Physics ,Proteomics ,Atomic and Molecular Physics, and Optics ,chemistry.chemical_compound ,Optical tweezers ,chemistry ,DNA nanotechnology ,Nanobiotechnology ,General Materials Science ,Electrical and Electronic Engineering ,DNA - Abstract
Decoding the identity of biomolecules from trace samples is a longstanding goal in the field of biotechnology. Advances in DNA analysis have substantially affected clinical practice and basic research, but corresponding developments for proteins face challenges due to their relative complexity and our inability to amplify them. Despite progress in methods such as mass spectrometry and mass cytometry, single-molecule protein identification remains a highly challenging objective. Towards this end, we combine DNA nanotechnology with single-molecule force spectroscopy to create a mechanically reconfigurable DNA nanoswitch caliper capable of measuring multiple coordinates on single biomolecules with atomic resolution. Using optical tweezers, we demonstrate absolute distance measurements with angstrom-level precision for both DNA and peptides, and using multiplexed magnetic tweezers, we demonstrate quantification of relative abundance in mixed samples. Measuring distances between DNA-labelled residues, we perform single-molecule fingerprinting of synthetic and natural peptides, and show discrimination, within a heterogeneous population, between different posttranslational modifications. DNA nanoswitch calipers are a powerful and accessible tool for characterizing distances within nanoscale complexes that will enable new applications in fields such as single-molecule proteomics. DNA nanoswitch calipers can measure distances within single molecules with atomic resolution. Applied to single-molecule proteomics, they can enable the identification and quantification of molecules in trace samples via mechanical fingerprinting.
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- 2021
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28. In Vivo Biosensors for Directed Protein Evolution
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Ee Lui Ang and Song Buck Tay
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Riboswitch ,Biochemistry ,In vivo ,Chemistry ,Aptamer ,Mutagenesis (molecular biology technique) ,Protein engineering ,Biosensor ,Transcription factor ,Protein evolution - Published
- 2021
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29. Amyloid β-Binding Bifunctional Chelators with Favorable Lipophilicity for 64Cu Positron Emission Tomography Imaging in Alzheimer’s Disease
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Truc T. Huynh, Buck E. Rogers, Liviu M. Mirica, Yujue Wang, Hong Jun Cho, and Yung Ching Wang
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Biodistribution ,medicine.diagnostic_test ,Amyloid ,Orders of magnitude (mass) ,Inorganic Chemistry ,chemistry.chemical_compound ,chemistry ,Positron emission tomography ,Lipophilicity ,medicine ,Biophysics ,Carboxylate ,Physical and Theoretical Chemistry ,Bifunctional ,Ex vivo - Abstract
Herein, we report a new series of bifunctional chelators (BFCs) with a high affinity for amyloid aggregates, a strong binding affinity toward Cu(II), and favorable lipophilicity for potential blood-brain barrier penetration. The alkyl carboxylate ester pendant arms offer up to 3 orders of magnitude higher binding affinity toward Cu(II) and enable the BFCs to form stable 64Cu-radiolabeled complexes. Among the five compounds tested, the 64Cu-YW-7 and 64Cu-YW-10 complexes exhibit strong and specific staining of amyloid plaques in ex vivo autoradiography studies. Importantly, these BFCs have promising partition coefficient (log Doct) values of 0.91-1.26 and show some brain uptake in biodistribution studies using CD-1 mice. Overall, these BFCs could serve as lead compounds for the development of positron emission tomography imaging agents for AD diagnosis.
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- 2021
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30. IR linewidth and intensity amplifications of nitrile vibrations report nuclear-electronic couplings and associated structural heterogeneity in radical anions†
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Eric W. Reinheimer, David C. Grills, Tomoyasu Mani, Jason T. Buck, Reid W. Wilson, and Juchao Yan
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Molecular wire ,Laser linewidth ,Chemistry ,Materials science ,Chemical physics ,Electric field ,Molecule ,Molecular electronics ,Charge (physics) ,General Chemistry ,Electron ,Dihedral angle - Abstract
Conjugated molecular chains have the potential to act as “molecular wires” that can be employed in a variety of technologies, including catalysis, molecular electronics, and quantum information technologies. Their successful application relies on a detailed understanding of the factors governing the electronic energy landscape and the dynamics of electrons in such molecules. We can gain insights into the energetics and dynamics of charges in conjugated molecules using time-resolved infrared (TRIR) detection combined with pulse radiolysis. Nitrile ν(C Created by potrace 1.16, written by Peter Selinger 2001-2019 N) bands can act as IR probes for charges, based on IR frequency shifts, because of their exquisite sensitivity to the degree of electron delocalization and induced electric field. Here, we show that the IR intensity and linewidth can also provide unique and complementary information on the nature of charges. Quantifications of IR intensity and linewidth in a series of nitrile-functionalized oligophenylenes reveal that the CN vibration is coupled to the nuclear and electronic structural changes, which become more prominent when an excess charge is present. We synthesized a new series of ladder-type oligophenylenes that possess planar aromatic structures, as revealed by X-ray crystallography. Using these, we demonstrate that CN vibrations can report charge fluctuations associated with nuclear movements, namely those driven by motions of flexible dihedral angles. This happens only when a charge has room to fluctuate in space., Quantification of the intensity and linewidth of the ν(CN) IR band in a series of neutral and anionic nitrile-functionalized oligophenylenes reveals that the CN vibration is coupled to nuclear and electronic structural changes.
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- 2021
31. Reducing Environmental Pollution by Antibiotics through Design for Environmental Degradation
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Marion Buck, Klaus Kümmerer, Christian Pfeifer, Axel Pahl, Christoph Leder, Manfred Kietzmann, Morten Suk, Tushar Rastogi, Stefanie Lorenz, and Daniel Jonas
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Green chemistry ,medicine.drug_class ,General Chemical Engineering ,Antibiotics ,Environmental pollution ,010501 environmental sciences ,Sustainability Science ,01 natural sciences ,03 medical and health sciences ,Environmental protection ,medicine ,Environmental Chemistry ,Environmental degradation ,Benign by design ,030304 developmental biology ,0105 earth and related environmental sciences ,0303 health sciences ,Renewable Energy, Sustainability and the Environment ,Sustainable pharmacy ,General Chemistry ,3. Good health ,Chemistry ,Environmental science ,Fluoroquinolones - Abstract
The spread of antibiotic-resistant pathogenic bacteria is an increasing health issue worldwide. A possible origin of antibiotic resistance could be the persistence of antibiotics in the aquatic environment. To tackle this problem, restricted control of application of antibiotics in human and veterinary medicine has been proposed. However, these measures do not prevent the spreadof antibiotic resistance but may delay the process, since antibiotics are still continuously emitted into the environment and many persist there. Derived from ciprofloxacin (CIP), CIP-Hemi, a fluoroquinolone with improved environmental properties, was developed following the benign by design approach and using insilico and in vitro methods. CIP-Hemi was designed to maintain its required metabolic stability (human liver microsomes, intestinal microsomes, blood plasma) and antibiotic activity (MIC in the μg mL−1 range) against the target while transforming into an inactive fragment (CIP-d-CP) and a degradable linker present under acidic conditions, e.g., after excretion or when released into theenvironment. Moreover, CIP-Hemi and CIP-d-CP showed weaker cytotoxic and mutagenic or genotoxic effects compared to the parent compound CIP and therefore underline the feasibility of CIP-Hemi as a viable antibiotic drug candidate, demonstrating benign by design as a promising approach.
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- 2021
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32. Amphiphilic Distyrylbenzene Derivatives as Potential Therapeutic and Imaging Agents for Soluble and Insoluble Amyloid β Aggregates in Alzheimer’s Disease
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Buck E. Rogers, Liviu M. Mirica, Liang Sun, Yiran Huang, Andres S. Arango, Emad Tajkhorshid, Hong Jun Cho, Truc T. Huynh, Soumyo Sen, and Nilantha Bandara
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Amyloid ,Biodistribution ,Fluorescence-lifetime imaging microscopy ,Mice, Transgenic ,Plaque, Amyloid ,Peptide ,Biochemistry ,Article ,Catalysis ,Styrenes ,Mice ,Colloid and Surface Chemistry ,Alzheimer Disease ,In vivo ,Amphiphile ,medicine ,Animals ,Moiety ,Molecule ,chemistry.chemical_classification ,Amyloid beta-Peptides ,Molecular Structure ,Microglia ,Chemistry ,General Chemistry ,Peptide Fragments ,Neuroprotective Agents ,medicine.anatomical_structure ,Drug Design ,Positron-Emission Tomography ,Biophysics ,Protein Binding - Abstract
Alzheimer’s Disease (AD) is the most common neurodegenerative disease, and efficient therapeutic and early diagnostic agents for AD are still lacking. Herein, we report the development of a novel amphiphilic compound, LS-4, generated by linking a hydrophobic amyloid-binding distyrylbenzene fragment with a hydrophilic triazamacrocycle, which dramatically increases the binding affinity toward various amyloid β (Aβ) peptide aggregates, especially for soluble Aβ oligomers. Moreover, upon the administration of LS-4 to 5xFAD mice, fluorescence imaging of LS-4-treated brain sections reveals that LS-4 can penetrate the blood-brain barrier and bind to the Aβ oligomers in vivo. In addition, the treatment of 5xFAD mice with LS-4 reduces the amount of both amyloid plaques and associated phosphorylated tau aggregates vs the vehicle-treated 5xFAD mice, while microglia activation is also reduced. Molecular dynamics simulations corroborate the observation that introducing a hydrophilic moiety into the molecular structure of LS-4 can enhance the electrostatic interactions with the polar residues of the Aβ species. Finally, exploiting the Cu(2+)-chelating property of the triazamacrocycle, we performed a series of imaging and biodistribution studies that show the (64)Cu-LS-4 complex binds to the amyloid plaques and can accumulate to a significantly larger extent in the 5xFAD mouse brains vs the wild-type controls. Overall, these results illustrate that the novel strategy, to employ an amphiphilic molecule containing a hydrophilic moiety attached to a hydrophobic amyloid-binding fragment, can increase the binding affinity for both soluble and insoluble Aβ aggregates and can thus be used to detect and regulate various Aβ species in AD.
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- 2021
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33. Photodynamic Efficiency of Xanthene Dyes and Their Phototoxicity against a Carcinoma Cell Line: A Computational and Experimental Study
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Suelen T. G. Buck, Fernanda Bettanin, Ednilson Orestes, Paula Homem-de-Mello, Hidetake Imasato, Rommel B. Viana, Janice R. Perussi, and Albérico B. F. da Silva
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Chemistry ,QD1-999 - Abstract
The aim of this study is to assess the insights of molecular properties of the xanthene dyes [fluorescein (FL), Rose Bengal (RB), erythrosin B (EB), and eosin Y (EY)] to correlate systematically their photodynamic efficiency as well as their phototoxicity against a carcinoma cell line. The phototoxicity was evaluated by comparing the values of the medium inhibitory concentration (IC50) upon HEp-2 cells with the xanthene corresponding photodynamic activity using the uric acid as a chemical dosimeter and their octanol-water partition coefficient (logP). RB was the more cytotoxic dye against HEp-2 cell line and the most efficient photosensitizer in causing photoxidation of uric acid; nevertheless it was the only one characterized as being hydrophobic among the xanthenes studied here. On the other hand, it was observed that the halogen substituents increased the hydrophilicity and photodynamic activity, consistent with the cytotoxic experiments. Furthermore, the reactivity index parameters, electric dipole moment, molecular volume, and the frontier orbitals were also obtained by the Density Functional Theory (DFT). The lowest dipole moment and highest molecular volume of RB corroborate with its highest hydrophobicity due to heavy atom substituents like halogens, while the halogen substituents did not affect expressively the electronic features at all.
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- 2017
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34. Enigmatic persistence of dissolved organic matter in the ocean
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Dittmar, Lennartz, S.T., Buck-Wiese, Hansell, D.A., Santinelli, Vanni, Blasius, Hehemann, and J.-H.
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Enigmatic persistence of dissolved organic matter in the ocean ,chemistry.chemical_classification ,Atmospheric Science ,Ecology ,Ecology (disciplines) ,Context (language use) ,Biota ,Pollution ,chemistry ,Dissolved organic carbon ,Environmental science ,Organic matter ,Ecosystem ,Persistence (discontinuity) ,Nature and Landscape Conservation ,Earth-Surface Processes - Abstract
Marine dissolved organic matter (DOM) contains more carbon than the combined stocks of Earth’s biota. Organisms in the ocean continuously release a myriad of molecules that become food for microheterotrophs, but, for unknown reasons, a residual fraction persists as DOM for millennia. In this Perspective, we discuss and compare two concepts that could explain this persistence. The long-standing ‘intrinsic recalcitrance’ paradigm attributes DOM stability to inherent molecular properties. In the ‘emergent recalcitrance’ concept, DOM is continuously transformed by marine microheterotrophs, with recalcitrance emerging on an ecosystems level. Both concepts are consistent with observations in the modern ocean, but they imply very different responses of the DOM pool to climate-related changes. To better understand DOM persistence, we propose a new overarching research strategy — the ecology of molecules — that integrates the concepts of intrinsic and emergent recalcitrance with the ecological and environmental context. Marine dissolved organic matter can persist for millennia, but the reasons for this phenomenon are unknown. This Perspective describes and compares two concepts — intrinsic and emergent recalcitrance — explaining marine organic matter persistence.
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- 2021
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35. Porous Honeycomb Self-Assembled Monolayers: Tripodal Adsorption and Hidden Chirality of Carboxylate Anchored Triptycenes on Ag
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Manfred Buck, Rodrigo Ortiz de la Morena, Saunak Das, Michael Zharnikov, Yoshiaki Shoji, Giulia Nascimbeni, Takanori Fukushima, Egbert Zojer, Fumitaka Ishiwari, University of St Andrews. School of Chemistry, and University of St Andrews. EaSTCHEM
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Triptycene ,Engineering ,NDAS ,chirality ,General Physics and Astronomy ,Self-assembled monolayers ,Nanotechnology ,02 engineering and technology ,010402 general chemistry ,01 natural sciences ,Article ,polymorphism ,chemistry.chemical_compound ,triptycene ,QD ,General Materials Science ,Carboxylate ,Polymorphism ,Chirality ,Scanning tunneling microscopy ,Training grant ,business.industry ,self-assembled monolayers ,General Engineering ,QD Chemistry ,021001 nanoscience & nanotechnology ,0104 chemical sciences ,chemistry ,Density functional theory calculations ,scanning tunneling microscopy ,density functional theory calculations ,0210 nano-technology ,business ,Chirality (chemistry) - Abstract
S.D. and M.Z thank the Helmholtz Zentrum Berlin for the allocation of synchrotron radiation beamtime at BESSY II and financial support. The work was financially supported by the German Research Foundation (Deutsche Forschungsgemeinschaft; DFG) via grant ZH 63/39-1 (S.D. and M.Z.), EPSRC (doctoral training grant, R.O.d.l.M.), and CREST (Japan Science and Technology Agency; JST) via grant JPMJCR18I4 (T.F.) and also supported in part by “Dynamic Alliance for Open Innovation Bridging Human, Environment and Materials” from MEXT, Japan. The authors acknowledge financial support through the Austrian Science Fund (FWF): P28051-N36. Molecules with tripodal anchoring to substrates represent a versatile platform for the fabrication of robust self-assembled monolayers (SAMs), complementing the conventional monopodal approach. In this context, we studied the adsorption of 1,8,13-tricarboxytriptycene (Trip-CA) on Ag(111), mimicked by a bilayer of silver atoms underpotentially deposited on Au. While tripodal SAMs frequently suffer from poor structural quality and inhomogeneous bonding configurations, the triptycene scaffold featuring three carboxylic acid anchoring groups yields highly crystalline SAM structures. A pronounced polymorphism is observed, with the formation of distinctly different structures depending on preparation conditions. Besides hexagonal molecular arrangements, the occurrence of a honeycomb structure is particularly intriguing as such an open structure is unusual for SAMs consisting of upright-standing molecules. Advanced spectroscopic tools reveal an equivalent bonding of all carboxylic acid anchoring groups. Notably, density functional theory calculations predict a chiral arrangement of the molecules in the honeycomb network, which, surprisingly, is not apparent in experimental scanning tunneling microscopy (STM) images. This seeming discrepancy between theory and experiment can be resolved by considering the details of the actual electronic structure of the adsorbate layer. The presented results represent an exemplary showcase for the intricacy of interpreting STM images of complex molecular films. They are also further evidence for the potential of triptycenes as basic building blocks for generating well-defined layers with unusual structural motifs. Publisher PDF
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- 2021
36. Sulfide Oxidation by 2,6-Bis[hydroxyl(methyl)amino]-4-morpholino-1,3,5-triazinatodioxomolybdenum(VI): Mechanistic Implications with DFT Calculations for a New Class of Molybdenum(VI) Complex
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Pierre Moënne-Loccoz, Jordan A. M. Gonzalez, Cayden X. Bullock, Ellie A. Draves, Louis Y. Kuo, Cooper S. Jamieson, and Buck L. H. Taylor
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chemistry.chemical_classification ,Sulfide ,010405 organic chemistry ,Thioanisole ,chemistry.chemical_element ,Sulfoxide ,Molybdate ,010402 general chemistry ,01 natural sciences ,Medicinal chemistry ,Redox ,0104 chemical sciences ,Inorganic Chemistry ,chemistry.chemical_compound ,chemistry ,Nucleophile ,Molybdenum ,Reactivity (chemistry) ,Physical and Theoretical Chemistry - Abstract
Sulfide oxidation is accomplished by a new class of dioxomolybdenum(VI) catalyst (1) that uses the tridentate 2,6-bis[hydroxyl(methyl)amino]-4-morpholino-1,3,5-triazine ligand to form a five-coordinate molybdenum(VI) center. Resonance Raman spectra show that the dioxo groups on the Mo(VI) oxygens readily exchange with water in an acetonitrile media that allows 18O labeling of catalyst 1. The model oxidation reaction was the conversion of thioanisole (2) to the corresponding sulfoxide with 4% of 1 using an equimolar amount of H2O2 in MeCN-d3. Oxygen-18 labeling experiments with either 18O-labeled 1 or 18O-labeled H2O2 are consistent with a sulfide oxygenation pathway that uses a η1-Mo(OOH) hydroxoperoxyl species (3). The hypothesized intermediate 3 is initially formed in a proton transfer reaction between 1 and H2O2. Oxidation is hypothesized via nucleophilic attack of the sulfide on 3 that is supported from a Hammett linear free-energy relationship for para-derivatives of 2. A Hammett reactivity constant (ρ) of -1.2 ± 0.2 was obtained, which is consistent with other ρ values found in prior sulfide oxidation reactions by group 6 complexes. An Eyring plot of the 2 oxidation by 1 gives an Ea of 63.0 ± 5.2 kJ/mol, which is slightly higher than that of a similar oxidation of 2 by the molybdenum(VI) complex, oxodiperoxo (pyridine-2-carboxylato)molybdate(VI) bis(pyridine-2-carboxylic acid) monohydrate (5). Computational modeling with density functional theory (DFT) of the complete reaction profile gave enthalpy and entropy of activations (64 kJ/mol and -120 J/mol·K, respectively) within 1 standard deviation of the experimental values, further supporting the hypothesized mechanism.
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- 2021
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37. Signaling-Biased and Constitutively Active Dopamine D2 Receptor Variant
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Timothy M. Dore, Naeem Asad, David C. Buck, Dineke S. Verbeek, Marina A. J. Tijssen, Kim A. Neve, John T. Williams, Alec F. Condon, Ujwal Shinde, Dayana Rodriguez-Contreras, Movement Disorder (MD), and Molecular Neuroscience and Ageing Research (MOLAR)
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Quinpirole ,Physiology ,G protein ,Cognitive Neuroscience ,Biochemistry ,Article ,Mice ,03 medical and health sciences ,0302 clinical medicine ,Dopamine ,Dopamine receptor D2 ,Cyclic AMP ,medicine ,Arrestin ,Animals ,Humans ,Inverse agonist ,Receptor ,030304 developmental biology ,0303 health sciences ,Receptors, Dopamine D2 ,Chemistry ,Cell Biology ,General Medicine ,Cell biology ,HEK293 Cells ,Dopamine Agonists ,Sulpiride ,030217 neurology & neurosurgery ,Signal Transduction ,medicine.drug - Abstract
A dopamine D2 receptor mutation was recently identified in a family with a novel hyperkinetic movement disorder. Compared to the wild type D2 receptor, the novel allelic variant D2-I(212)F activates a Gα(i1)β(1)γ(2) heterotrimer with higher potency and modestly enhanced basal activity in human embryonic kidney (HEK) 293 cells, and has decreased capacity to recruit arrestin3. We now report that omitting overexpressed G protein-coupled receptor kinase-2 (GRK2) decreased the potency and efficacy of quinpirole for arrestin recruitment. The relative efficacy of quinpirole for arrestin recruitment to D2-I(212)F compared to D2-WT was considerably lower without overexpressed GRK2 than with added GRK2. D2-I(212)F exhibited higher basal activation of Gα(oA) than Gα(i1), but little or no increase in the potency of quinpirole relative to D2-WT. Other signs of D2-I(212)F constitutive activity for G protein-mediated signaling, in addition to basal activation of Gα(i/o), were enhanced basal inhibition of forskolin-stimulated cyclic AMP accumulation that was reversed by the inverse agonists sulpiride and spiperone and a ~4-fold increase in the apparent affinity of D2-I(212)F for quinpirole, determined from competition binding assays. In mouse midbrain slices, inhibition of tonic current by the inverse agonist sulpiride in dopamine neurons expressing D2-I(212)F was consistent with our hypothesis of enhanced constitutive activity and sensitivity to dopamine relative to D2-WT. Molecular dynamics simulations with D2 receptor models suggested that an ionic lock between the cytoplasmic ends of the third and sixth α-helices that constrains many G protein-coupled receptors in an inactive conformation spontaneously breaks in D2-I(212)F. Overall, these results confirm that D2-I(212)F is a constitutively active and signaling-biased D2 receptor mutant, and also suggest that the effect of the likely pathogenic variant in a given brain region will depend on the nature of G protein and GRK expression.
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- 2021
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38. ONC201 induces the unfolded protein response (UPR) in high‐ and low‐grade ovarian carcinoma cell lines and leads to cell death regardless of platinum sensitivity
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Sijana H. Dzinic, Marufa Rumman, Steven Buck, Ira Winer, Lisa Polin, and Julie L. Boerner
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0301 basic medicine ,Cancer Research ,Programmed cell death ,Organoplatinum Compounds ,endocrine system diseases ,Cell Survival ,Pyridines ,Antineoplastic Agents ,Carcinoma, Ovarian Epithelial ,03 medical and health sciences ,0302 clinical medicine ,Downregulation and upregulation ,Cell Line, Tumor ,medicine ,Humans ,Radiology, Nuclear Medicine and imaging ,MTT assay ,Viability assay ,Protein kinase B ,PI3K/AKT/mTOR pathway ,RC254-282 ,Original Research ,Cancer Biology ,Ovarian Neoplasms ,Cisplatin ,Cell Death ,Receptors, Dopamine D2 ,Chemistry ,low‐grade ovarian cancer ,Imidazoles ,apoptosis ,ONC201 ,Neoplasms. Tumors. Oncology. Including cancer and carcinogens ,unfolded protein response ,female genital diseases and pregnancy complications ,Up-Regulation ,Dopamine D2 Receptor Antagonists ,Pyrimidines ,030104 developmental biology ,Oncology ,Drug Resistance, Neoplasm ,Apoptosis ,030220 oncology & carcinogenesis ,Cancer research ,Female ,high‐grade ovarian cancer ,Signal Transduction ,medicine.drug - Abstract
Objectives Treatment of both platinum resistant high grade (HG) and low‐grade (LG) ovarian cancer (OVCA) poses significant challenges as neither respond well to conventional chemotherapy leading to morbidity and mortality. Identification of novel agents that can overcome chemoresistance is therefore critical. Previously, we have demonstrated that OVCA has basal upregulated unfolded protein response (UPR) and that targeting cellular processes leading to further and persistent upregulation of UPR leads to cell death. ONC201 is an orally bioavailable Dopamine Receptor D2 inhibitor demonstrating anticancer activity and was found to induce UPR. Given its unique properties, we hypothesized that ONC201 would overcome platinum resistance in OVCA. Methods Cisplatin sensitive and resistant HG OVCA and two primary LG OVCA cell lines were studied. Cell viability was determined using MTT assay. Cell migration was studied using wound healing assay. Apoptosis and mitochondrial membrane potential were investigated using flow cytometry. Analysis of pathway inhibition was performed by Western Blot. mRNA expression of UPR related genes were measured by qPCR. In vivo studies were completed utilizing axillary xenograft models. Co‐testing with conventional chemotherapy was performed to study synergy. Results ONC201 significantly inhibited cell viability and migration in a dose dependent manner with IC50’s from 1‐20 µM for both cisplatin sensitive and resistant HG and LG‐OVCA cell lines. ONC201 lead to upregulation of the pro‐apoptotic arm of the UPR, specifically ATF‐4/CHOP/ATF3 and increased the intrinsic apoptosispathway. The compensatory, pro‐survival PI3K/AKT/mTOR pathway was downregulated. In vivo, weekly dosing of single agent ONC201 decreased xenograft tumor size by ~50% compared to vehicle. ONC201 also demonstrated significant synergy with paclitaxel in a highly platinum resistant OVCA cell‐line (OV433). Conclusions Our findings demonstrate that ONC201 can effectively overcome chemoresistance in OVCA cells by blocking pro‐survival pathways and inducing the apoptotic arm of the UPR. This is a promising, orallybioavailable therapeutic agent to consider in clinical trials for patients with both HG and LG OVCA., ONC201 can effectively overcome chemoresistance in both high‐grade and low‐grade ovarian cancer cells by blocking pro‐survival pathways and inducing the apoptotic arm of the UPR. A weekly oral dose of ONC201 lowers the tumor burden in mice. This is a promising therapeutic agent in OVCA treatment and might consider for clinical translation.
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- 2021
39. Effective Prevention of Recurrent UTIs With Vaginal Estrogen: Pearls for a Urological Approach to Genitourinary Syndrome of Menopause
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Emory S. Buck, Rachel Rubin, and Vanessa A. Lukas
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medicine.medical_specialty ,medicine.drug_class ,Urology ,Urinary system ,030232 urology & nephrology ,Vaginal estrogen ,law.invention ,03 medical and health sciences ,chemistry.chemical_compound ,0302 clinical medicine ,Randomized controlled trial ,Recurrence ,Ospemifene ,law ,Internal medicine ,medicine ,Humans ,business.industry ,Genitourinary system ,Estrogens ,Syndrome ,medicine.disease ,Female Urogenital Diseases ,Menopause ,Administration, Intravaginal ,chemistry ,Estrogen ,030220 oncology & carcinogenesis ,Urinary Tract Infections ,Etiology ,business - Abstract
Objective To review the available data related to the prevention of recurrent urinary tract infection (rUTI) in postmenopausal women with vaginal estrogen preparations and provide the urologic community with the confidence to identify and treat genitourinary syndrome of menopause (GSM). Materials and Methods A literature search of MEDLINE and the Cochrane Central Register of Controlled Trials databases was performed to identify studies utilizing vaginal estrogen in the treatment of urological conditions related to rUTI and GSM. Results In the setting of untreated GSM, the etiology of rUTIs (at least 3 episodes of UTIs in 12 months or at least 2 episodes in 6 months) is not fully elucidated, but estrogen deficiency is a contributing factor. The diagnosis of GSM is primarily a clinical diagnosis supported by other objective findings including: a vaginal pH >5, decreased content of superficial cells, and/or increased proportion of parabasal cells on vaginal maturation index. Local vaginal estrogen, dehydroepiandrosterone (prasterone), and ospemifene are commonly used GSM treatments. Thirty-one trials were identified utilizing estrogen preparations for rUTI in postmenopausal women. Conclusion Overall, multiple randomized clinical trials have successfully been completed to show the efficacy of local estrogen preparations for the treatment of rUTIs. This high yield review provides a framework for assessing GSM, prescribing recommendations for local vaginal hormone preparations, and a summary of the substantial evidence supporting the new 2019 American Urological Association/Canadian Urological Association/Society of Urodynamics, Female Pelvic Medicine and Urogenital Reconstruction Guidance for local vaginal estrogen use for rUTI.
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- 2021
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40. Aberrant myelomonocytic CD56 expression in Down syndrome is frequent and not associated with leukemogenesis
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Jeffrey W. Taub, Batool Al‐Qanber, Süreyya Savaşan, Yaddanapudi Ravindranath, Steven Buck, and Manisha Gadgeel
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Acute leukemia ,Down syndrome ,medicine.medical_specialty ,Hematology ,Myeloid ,business.industry ,Myeloid leukemia ,General Medicine ,medicine.disease ,03 medical and health sciences ,chemistry.chemical_compound ,Leukemia ,0302 clinical medicine ,Immunophenotyping ,medicine.anatomical_structure ,RUNX1 ,chemistry ,hemic and lymphatic diseases ,030220 oncology & carcinogenesis ,Internal medicine ,Cancer research ,medicine ,business ,030215 immunology - Abstract
Children with Down syndrome (DS) are at an increased risk of developing transient abnormal myelopoiesis (TAM) and acute leukemia. Aberrant expression of CD56 has been observed on myeloid leukemic blasts in DS patients. In general, CD56 expression in acute myeloid leukemia (AML) is considered a promoter of leukemogenesis. We did a retrospective flow cytometric study to investigate mature myelomonocytic cell CD56 expression patterns in TAM, non-TAM, and leukemia cases with DS. Flow cytometric analysis showed that granulocyte and monocyte aberrant/dysplastic CD56 expression is an inherent characteristic of most DS patients irrespective of the presence of TAM or leukemia. Increased CD56 expression in monocyte and granulocyte populations in DS could be multifactorial; greater expression of RUNX1 secondary to the gene dose effect of trisomy 21 along with the maturational state of the cells are the potential contributors. Unlike AML seen in non-DS patients, CD56 overexpression in DS AML cases does not appear to play a role in leukemogenesis.
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- 2021
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41. Spreading of Micrometer-Sized Droplets under the Influence of Insoluble and Soluble Surfactants: A Numerical Study
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Thomas Antritter, Peter Hachmann, Tatiana Gambaryan-Roisman, Bernhard Buck, and Peter Stephan
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wetting ,spreading ,complex fluids ,surfactant ,computational fluid dynamics ,volume-of-fluid method ,Chemistry ,QD1-999 - Abstract
Wetting and spreading of surfactant solutions play an important role in many technical applications. In printing processes, the size of individual droplets is typically on the order of a few tens of microns. The purpose of this study is to develop a better understanding of the interaction between spreading and surfactant transport on these small length and related time scales. Therefore, numerical simulations based on the volume-of-fluid method including Marangoni stresses and transport of an insoluble or soluble surfactant are performed. The results for an insoluble surfactant show competing effects of Marangoni flow on the one hand, and a decreasing surfactant concentration as the droplet spreads on the other hand. Even in the case of a soluble surfactant, adsorption and desorption could only partly mitigate these effects, demonstrating the importance of the sorption kinetics for fast, small scale wetting processes.
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- 2019
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42. Machinability of Stone—Plastic Materials During Diamond Planing
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Zhaolong Zhu, Dietrich Buck, Xiaolei Guo, Pingxiang Cao, and Mats Ekevad
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composite material ,polycrystalline diamond cutter ,orthogonal cutting ,digital image correlation ,DIC analysis ,full-field mechanics ,machining properties ,Technology ,Engineering (General). Civil engineering (General) ,TA1-2040 ,Biology (General) ,QH301-705.5 ,Physics ,QC1-999 ,Chemistry ,QD1-999 - Abstract
This paper investigated the machinability of a stone–plastic composite (SPC) via orthogonal cutting with diamond cutters. The objective was to determine the effect of cutting depth on its machinability, including cutting forces, heat, chip formation, and cutting quality. Increased cutting depth promoted an increase in both frictional and normal forces, and also had a strong influence on the change in normal force. The cutting temperatures of chips and tool edges showed an increasing trend as cutting depth increased. However, the cutting heat was primarily absorbed by chips, with the balance accumulating in the cutting edge. During chip formation, the highest von Mises strain was mainly found in SPC ahead of the cutting edge, and the SPC to be removed partially passed its elastic limit, eventually forming chips with different shapes. Furthermore, the average surface roughness and the mean peak-to-valley height of machined surfaces all positively correlated to an increase in cutting depth. Finally, with an increase in cutting depth, the chip shape changed from tubular, to ribbon, to arc, to segmental, and finally, to helical chips. This evolution in chip shape reduced the fluctuation in cutting force, improving cutting stability and cutting quality.
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- 2019
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43. Structure-Based Design of Potent and Orally Active Isoindolinone Inhibitors of MDM2-p53 Protein–Protein Interaction
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Benoit Carbain, Keisha Hearn, Ildiko Maria Buck, Burcu Anil, Sarah J. Cully, Gianni Chessari, Jane A. Endicott, John Lunec, Neil T. Thompson, Juan Castro, Roger J. Griffin, Rhian S. Holvey, Karen Haggerty, Charlotte H. Revill, Ruth H. Bawn, Stephen R. Wedge, Christiane Riedinger, Christopher N. Johnson, Bernard T. Golding, Lynsey Fazal, Ian R. Hardcastle, Mladen Vinkovic, Claire E. Jennings, Jong Sook Ahn, Bian Zhang, Pamela A. Williams, Celine Cano, Suzannah J. Harnor, Ben Cons, Stephen J. Hobson, E. Anscombe, Jeffrey D. St. Denis, Steven Howard, David R. Newell, Emiliano Tamanini, Nicola E. Wilsher, Miller Duncan Charles, Huw D. Thomas, Timothy J. Blackburn, Martin E.M. Noble, Judith Reeks, Yan Zhao, and Luke Bevan
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Male ,Metabolite ,Mice, Nude ,Antineoplastic Agents ,Bone Neoplasms ,Isoindoles ,Pharmacology ,Crystallography, X-Ray ,01 natural sciences ,Structure-Activity Relationship ,03 medical and health sciences ,chemistry.chemical_compound ,Drug Stability ,In vivo ,Cell Line, Tumor ,Drug Discovery ,Animals ,Humans ,Structure–activity relationship ,neoplasms ,Cell Proliferation ,030304 developmental biology ,Mice, Inbred BALB C ,Osteosarcoma ,0303 health sciences ,Molecular Structure ,biology ,Chemistry ,Proto-Oncogene Proteins c-mdm2 ,Ligand (biochemistry) ,Xenograft Model Antitumor Assays ,Cytostasis ,Small molecule ,In vitro ,0104 chemical sciences ,Macaca fascicularis ,010404 medicinal & biomolecular chemistry ,Microsomes, Liver ,biology.protein ,Molecular Medicine ,Mdm2 ,Female ,Protein Multimerization ,Tumor Suppressor Protein p53 ,Protein Binding - Abstract
Inhibition of murine double minute 2 (MDM2)-p53 protein-protein interaction with small molecules has been shown to reactivate p53 and inhibit tumor growth. Here, we describe rational, structure-guided, design of novel isoindolinone-based MDM2 inhibitors. MDM2 X-ray crystallography, quantum mechanics ligand-based design, and metabolite identification all contributed toward the discovery of potent in vitro and in vivo inhibitors of the MDM2-p53 interaction with representative compounds inducing cytostasis in an SJSA-1 osteosarcoma xenograft model following once-daily oral administration.
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- 2021
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44. Cerebellar Kv3.3 potassium channels activate TANK-binding kinase 1 to regulate trafficking of the cell survival protein Hax-1
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Pasquale D’Acunzo, Matija Sestan-Pesa, Yalan Zhang, Tamas L. Horvath, Klara Szigeti-Buck, Richard A. Flavell, Jorge Henao-Mejia, Efrat Levy, Milan Stoiljkovic, Adam Williams, Leonard K. Kaczmarek, and Luis Varela
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Male ,0301 basic medicine ,Cerebellum ,Cell Survival ,Science ,General Physics and Astronomy ,Protein Serine-Threonine Kinases ,Exosomes ,Exosome ,Article ,General Biochemistry, Genetics and Molecular Biology ,Mice ,03 medical and health sciences ,0302 clinical medicine ,TANK-binding kinase 1 ,Interneurons ,medicine ,Animals ,Ion channel ,Multidisciplinary ,Chemistry ,Intracellular Signaling Peptides and Proteins ,Depolarization ,General Chemistry ,Potassium channel ,Cell biology ,Protein Transport ,Phenotype ,030104 developmental biology ,medicine.anatomical_structure ,Neurology ,Shaw Potassium Channels ,Membrane protein ,nervous system ,Mutation ,Female ,Signal transduction ,030217 neurology & neurosurgery ,Neuroscience ,Signal Transduction - Abstract
Mutations in KCNC3, which encodes the Kv3.3 potassium channel, cause degeneration of the cerebellum, but exactly how the activity of an ion channel is linked to the survival of cerebellar neurons is not understood. Here, we report that Kv3.3 channels bind and stimulate Tank Binding Kinase 1 (TBK1), an enzyme that controls trafficking of membrane proteins into multivesicular bodies, and that this stimulation is greatly increased by a disease-causing Kv3.3 mutation. TBK1 activity is required for the binding of Kv3.3 to its auxiliary subunit Hax-1, which prevents channel inactivation with depolarization. Hax-1 is also an anti-apoptotic protein required for survival of cerebellar neurons. Overactivation of TBK1 by the mutant channel leads to the loss of Hax-1 by its accumulation in multivesicular bodies and lysosomes, and also stimulates exosome release from neurons. This process is coupled to activation of caspases and increased cell death. Our studies indicate that Kv3.3 channels are directly coupled to TBK1-dependent biochemical pathways that determine the trafficking of cellular constituents and neuronal survival., How the activity of the neuronal Kv3.3 voltage-dependent channel is regulated is unclear. Here, the authors show that the known Kv3.3 channel complex with Hax1, which affects spinal cerebellar ataxia, regulates the enzyme Tank Binding Kinase 1, modulating survival of cerebellar neurons.
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- 2021
45. Questions and Controversies in the Clinical Application of Tyrosine Kinase Inhibitors to Treat Patients with Radioiodine-Refractory Differentiated Thyroid Carcinoma: Expert Perspectives
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Klemens Scheidhauer, Andreas K. Buck, Michael C. Kreissl, Christoph W. M. Reuter, Andreas Darr, Ingo Brink, Ina Binse, Ute König, Christine Dierks, Christine Koch, Markus Luster, Matthias Schott, Holger S. Willenberg, Frederik A. Verburg, Holger Amthauer, Andreas Zielke, and Radiology & Nuclear Medicine
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Oncology ,Sorafenib ,medicine.medical_specialty ,Endocrinology, Diabetes and Metabolism ,Clinical Biochemistry ,Medizin ,Psychological intervention ,030209 endocrinology & metabolism ,Subgroup analysis ,Antineoplastic Agents ,Review ,lenvatinib ,Biochemistry ,second-line therapy ,03 medical and health sciences ,chemistry.chemical_compound ,0302 clinical medicine ,Endocrinology ,multi-kinase inhibitors ,SDG 3 - Good Health and Well-being ,treatment initiation and discontinuation ,Internal medicine ,medicine ,Humans ,Dosing ,Thyroid Neoplasms ,Protein Kinase Inhibitors ,Response rate (survey) ,Performance status ,Dose-Response Relationship, Drug ,business.industry ,Phenylurea Compounds ,Biochemistry (medical) ,General Medicine ,Protein-Tyrosine Kinases ,dosing ,3. Good health ,chemistry ,Tolerability ,030220 oncology & carcinogenesis ,Quinolines ,business ,Lenvatinib ,medicine.drug - Abstract
Notwithstanding regulatory approval of lenvatinib and sorafenib to treat radioiodine-refractory differentiated thyroid carcinoma (RAI-R DTC), important questions and controversies persist regarding this use of these tyrosine kinase inhibitors (TKIs). RAI-R DTC experts from German tertiary referral centers convened to identify and explore such issues; this paper summarizes their discussions. One challenge is determining when to start TKI therapy. Decision-making should be shared between patients and multidisciplinary caregivers, and should consider tumor size/burden, growth rate, and site(s), the key drivers of RAI-R DTC morbidity and mortality, along with current and projected tumor-related symptomatology, co-morbidities, and performance status. Another question involves choice of first-line TKIs. Currently, lenvatinib is generally preferred, due to greater increase in progression-free survival versus placebo treatment and higher response rate in its pivotal trial versus that of sorafenib; additionally, in those studies, lenvatinib but not sorafenib showed overall survival benefit in subgroup analysis. Whether recommended maximum or lower TKI starting doses better balance anti-tumor effects versus tolerability is also unresolved. Exploratory analyses of lenvatinib pivotal study data suggest dose-response effects, possibly favoring higher dosing; however, results are awaited of a prospective comparison of lenvatinib starting regimens. Some controversy surrounds determination of net therapeutic benefit, the key criterion for continuing TKI therapy: if tolerability is acceptable, overall disease control may justify further treatment despite limited but manageable progression. Future research should assess potential guideposts for starting TKIs; fine-tune dosing strategies and further characterize antitumor efficacy; and evaluate interventions to prevent and/or treat TKI toxicity, particularly palmar-plantar erythrodysesthesia and fatigue.
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- 2021
46. Temporality in Renga
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Heidi Buck-Albulet
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Aesthetics ,Chemistry ,General Engineering ,Temporality ,New media - Abstract
This paper highlights time concepts and the organisation and structure of time in the practice of renga, Japanese ‘linked poetry’. As renga is a genre of poetry created in groups, the study will not only focus on the poems themselves (the texts produced), but on the meetings that bring forth the texts (the performance), the manuscripts that are written there (the material) and the social environment in which the performances take place (the setting). By analysing the main features of each of these four areas and focusing on time, change and persistence, I aim to show how closely they are interconnected and also provide the reader with the knowledge necessary to appreciate the complexity of renga as an integral Gesamtkunstwerk. While my focus is on contemporary renga poetry here, I will also consider aspects of its history, which is a vital key to understanding this art.
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- 2021
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47. Vitamin D3 supplementation does not enhance the effects of resistance training in older adults
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Daniel Buck, Rafi Ahmad, Daniel Hammarström, Karianne Pedersen, Håvard Hamarsland, Bent R. Rønnestad, Stian Ellefsen, Ragnvald B Steile, Anne Cecilie Lian Lie, Eirik Grindaker, Knut Sindre Mølmen, Håvard Nygaard, Jon Elling Whist, Atle Lie Eriksen, Tor A. Strand, Lise Koll, Yusuf Khan, and Marita Hanestadhaugen
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0301 basic medicine ,Muscle tissue ,Vitamin ,Male ,Strength training ,Physiology ,Blood lipids ,Diseases of the musculoskeletal system ,Placebo ,law.invention ,03 medical and health sciences ,chemistry.chemical_compound ,0302 clinical medicine ,Randomized controlled trial ,law ,Physiology (medical) ,medicine ,Humans ,Orthopedics and Sports Medicine ,Vitamin D ,Cholecalciferol ,Aged ,COPD ,business.industry ,QM1-695 ,VDP::Medisinske Fag: 700::Basale medisinske, odontologiske og veterinærmedisinske fag: 710 ,Resistance Training ,Original Articles ,Vitamins ,Middle Aged ,medicine.disease ,VDP::Medical disciplines: 700::Basic medical, dental and veterinary science disciplines: 710 ,030104 developmental biology ,medicine.anatomical_structure ,RC925-935 ,chemistry ,030220 oncology & carcinogenesis ,Muscle plasticity ,Human anatomy ,Dietary Supplements ,Original Article ,Female ,business - Abstract
Background: Lifestyle therapy with resistance training is a potent measure to counteract age-related loss in muscle strength and mass. Unfortunately, many individuals fail to respond in the expected manner. This phenomenon is particularly common among older adults and those with chronic diseases (e.g. chronic obstructive pulmonary disease, COPD) and may involve endocrine variables such as vitamin D. At present, the effects of vitamin D supplementation on responses to resistance training remain largely unexplored. Methods: Ninety-five male and female participants (healthy, n = 71; COPD, n = 24; age 68 ± 5 years) were randomly assigned to receive either vitamin D3 or placebo supplementation for 28 weeks in a double-blinded manner (latitude 61°N, September-May). Seventy-eight participants completed the RCT, which was initiated by 12 weeks of supplementation-only (two weeks with 10 000 IU/day, followed by 2000 IU/day), followed by 13 weeks of combined supplementation (2000 IU/day) and supervised whole-body resistance training (twice weekly), interspersed with testing and measurements. Outcome measures included multiple assessments of muscle strength (nvariables = 7), endurance performance (n = 6), and muscle mass (n = 3, legs, primary), as well as muscle quality (legs), muscle biology (m. vastus lateralis; muscle fibre characteristics, transcriptome), and health-related variables (e.g. visceral fat mass and blood lipid profile). For main outcome domains such as muscle strength and muscle mass, weighted combined factors were calculated from the range of singular assessments. Results: Overall, 13 weeks of resistance training increased muscle strength (13% ± 8%), muscle mass (9% ± 8%), and endurance performance (one-legged, 23% ± 15%; whole-body, 8% ± 7%), assessed as weighted combined factors, and were associated with changes in health variables (e.g. visceral fat, -6% ± 21%; [LDL]serum , -4% ± 14%) and muscle tissue characteristics such as fibre type proportions (e.g. IIX, -3% points), myonuclei per fibre (30% ± 65%), total RNA/rRNA abundances (15%/6-19%), and transcriptome profiles (e.g. 312 differentially expressed genes). Vitamin D3 supplementation did not affect training-associated changes for any of the main outcome domains, despite robust increases in [25(OH)D]serum (∆49% vs. placebo). No conditional effects were observed for COPD vs. healthy or pre-RCT [25(OH)D]serum . In secondary analyses, vitamin D3 affected expression of gene sets involved in vascular functions in muscle tissue and strength gains in participants with high fat mass, which advocates further study. Conclusions: Vitamin D3 supplementation did not affect muscular responses to resistance training in older adults with or without COPD. Keywords: Cholecalciferol; Muscle plasticity; Strength training. © 2021 The Authors. Journal of Cachexia, Sarcopenia and Muscle published by John Wiley & Sons Ltd on behalf of Society on Sarcopenia, Cachexia and Wasting Disorders. publishedVersion
- Published
- 2021
48. Steroid hormones and human choriogonadotropin influence the distribution of alpha6-integrin and desmoplakin 1 in gland-like endometrial epithelial spheroids
- Author
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J Neulen, Rudolf E. Leube, Irmgard Classen-Linke, Volker U. Buck, Benjamin Rösing, M T Kohlen, and A K Sternberg
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0301 basic medicine ,Histology ,Integrin ,Integrin alpha6 ,Human endometrium ,Chorionic Gonadotropin ,Adherens junction ,Extracellular matrix ,Endometrium ,03 medical and health sciences ,0302 clinical medicine ,Ishikawa cell line ,Spheroids, Cellular ,medicine ,Humans ,Gonadal Steroid Hormones ,Cell adhesion ,Molecular Biology ,Cells, Cultured ,3D cell culture system ,Epithelial polarity ,Basement membrane ,Original Paper ,030219 obstetrics & reproductive medicine ,biology ,Cell adhesion molecule ,Chemistry ,Desmoplakin ,Cell Biology ,Cell biology ,Medical Laboratory Technology ,030104 developmental biology ,medicine.anatomical_structure ,Endometrial receptivity ,Desmoplakins ,biology.protein ,Female - Abstract
In human glandular endometrial epithelial cells, desmosomal and adherens junction proteins have been shown to extend from a subapically restricted lateral position to the entire lateral membrane during the implantation window of the menstrual cycle. Similarly, a menstrual cycle stage-dependent redistribution of the extracellular matrix adhesion protein α6-integrin has been reported. These changes are believed to be important for endometrial receptiveness and successful embryo implantation. To prove the hypothesis that steroid hormones and human choriogonadotropin can induce the redistribution of these adhesion molecules, we used the human endometrial cell line Ishikawa in a 3D culture system. Gland-like spheroids were grown in reconstituted basement membrane (Matrigel™). The lumen-bearing spheroids were treated for 2 or 4 days with ovarian steroids or human choriogonadotropin and then assessed by immunofluorescence microscopy. In addition, human endometrial biopsies were obtained from patients, who were in therapy for assisted reproductive technology, and were examined in parallel. Lateral redistribution of the desmosomal plaque protein desmoplakin 1 was observed in the spheroids treated either with progesterone, medroxyprogesterone acetate or human choriogonadotropin. Furthermore, the extracellular matrix adhesion protein α6-integrin showed an increased lateral membrane localization upon gestagen stimulation in the 3D culture system. The results of this study demonstrate that the 3D endometrial Ishikawa cell culture might be suited as an experimental model system to prove the effect of hormonal changes like those occurring during the window of implantation. Supplementary Information The online version contains supplementary material available at 10.1007/s00418-020-01960-z.
- Published
- 2021
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49. Intraindividual comparison of [177Lu]Lu-DOTA-EB-TATE and [177Lu]Lu-DOTA-TOC
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Constantin Lapa, Andreas Schirbel, Philipp E. Hartrampf, Heribert Hänscheid, and Andreas K. Buck
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business.industry ,Somatostatin receptor ,medicine.medical_treatment ,Albumin ,General Medicine ,Radiation therapy ,chemistry.chemical_compound ,Somatostatin ,chemistry ,Radionuclide therapy ,DOTA ,Medicine ,Radiology, Nuclear Medicine and imaging ,ddc:610 ,Biological half-life ,Nuclear medicine ,business ,Evans Blue - Abstract
Purpose The radiolabelled somatostatin analogue [177Lu]Lu-DOTA-EB-TATE binds to albumin via Evans blue, thereby increasing the residence time in the blood and potentially allowing more therapeutic agent to be absorbed into the target tissue during peptide receptor radionuclide therapy. It was tested in selected patients whether the substance is superior to [177Lu]Lu-DOTA-TOC. Methods Activity kinetics in organs and tumours after [177Lu]Lu-DOTA-EB-TATE and [177Lu]Lu-DOTA-TOC were compared intraindividually in five patients with progressive somatostatin receptor-positive disease scheduled for radionuclide therapy. Results In comparison to [177Lu]Lu-DOTA-TOC, tumour doses per administered activity were higher for [177Lu]Lu-DOTA-EB-TATE in 4 of 5 patients (median ratio: 1.7; range: 0.9 to 3.9), kidney doses (median ratio: 3.2; range: 1.6 to 9.8) as well as spleen doses (median ratio: 4.7; range 1.2 to 6.2) in all patients, and liver doses in 3 of 4 evaluable patients (median ratio: 4.0; range: 0.7 to 4.9). The tumour to critical organs absorbed dose ratios were higher after [177Lu]Lu-DOTA-TOC in 4 of 5 patients. Conclusions Prior to a treatment with [177Lu]Lu-DOTA-EB-TATE, it should be assessed individually whether the compound is superior to established substances.
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- 2021
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50. The receptor DNGR-1 signals for phagosomal rupture to promote cross-presentation of dead-cell-associated antigens
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Santiago Zelenay, Caetano Reis e Sousa, Felix Randow, Hefin Rhys, Neil C. Rogers, Hanna Blees, Oliver Schulz, Michael D. Buck, Cara J. Ellison, Conor M. Henry, Eleanor Childs, David C. Thomas, Venizelos Papayannopoulos, Johnathan Canton, Sebastian Amigorena, Andrés Alloatti, Lucy M. Collinson, Marie-Charlotte Domart, The Francis Crick Institute [London], University of Manchester [Manchester], Immunité et cancer (U932), Institut Curie [Paris]-Institut National de la Santé et de la Recherche Médicale (INSERM), MRC Laboratory of Molecular Biology [Cambridge, UK] (LMB), University of Cambridge [UK] (CAM)-Medical Research Council, University of Cambridge [UK] (CAM), Institut Curie [Paris], Imperial College London, and AMIGORENA, Sebastian
- Subjects
0301 basic medicine ,T-Lymphocytes ,[SDV]Life Sciences [q-bio] ,Immunology ,Antigen presentation ,Ligands ,Major histocompatibility complex ,Article ,Mice ,03 medical and health sciences ,Cross-Priming ,0302 clinical medicine ,Antigen ,Phagosomes ,Animals ,Humans ,Syk Kinase ,Immunology and Allergy ,Lectins, C-Type ,Phosphorylation ,Receptors, Immunologic ,Antigen Presentation ,Cell Death ,biology ,Chemistry ,MHC class I antigen ,Histocompatibility Antigens Class I ,NADPH Oxidases ,Cross-presentation ,Dendritic Cells ,Acquired immune system ,Coculture Techniques ,3. Good health ,Cell biology ,[SDV] Life Sciences [q-bio] ,HEK293 Cells ,RAW 264.7 Cells ,030104 developmental biology ,Endocytic vesicle ,Receptors, Mitogen ,biology.protein ,Reactive Oxygen Species ,CD8 ,Signal Transduction ,030215 immunology - Abstract
International audience; Type 1 conventional dendritic (cDC1) cells are necessary for cross-presentation of many viral and tumor antigens to CD8+ T cells. cDC1 cells can be identified in mice and humans by high expression of DNGR-1 (also known as CLEC9A), a receptor that binds dead-cell debris and facilitates XP of corpse-associated antigens. Here, we show that DNGR-1 is a dedicated XP receptor that signals upon ligand engagement to promote phagosomal rupture. This allows escape of phagosomal contents into the cytosol, where they access the endogenous major histocompatibility complex class I antigen processing pathway. The activity of DNGR-1 maps to its signaling domain, which activates SYK and NADPH oxidase to cause phagosomal damage even when spliced into a heterologous receptor and expressed in heterologous cells. Our data reveal the existence of innate immune receptors that couple ligand binding to endocytic vesicle damage to permit MHC class I antigen presentation of exogenous antigens and to regulate adaptive immunity.
- Published
- 2020
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