2,192 results on '"MARTIN C"'
Search Results
2. Commemorating two centuries of iodine research: an interdisciplinary overview of current research.
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Küpper FC, Feiters MC, Olofsson B, Kaiho T, Yanagida S, Zimmermann MB, Carpenter LJ, Luther GW 3rd, Lu Z, Jonsson M, and Kloo L
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- Animals, Environmental Monitoring, History, 19th Century, History, 20th Century, History, 21st Century, Humans, Iodine chemistry, Iodine Compounds analysis, Iodine Compounds chemistry, Iodine Compounds metabolism, Thyroid Gland metabolism, Chemistry history, Iodine analysis, Iodine metabolism
- Abstract
Iodine was discovered as a novel element in 1811 during the Napoleonic Wars. To celebrate the bicentennial anniversary of this event we reflect on the history and highlight the many facets of iodine research that have evolved since its discovery. Iodine has an impact on many aspects of life on Earth as well as on human civilization. It is accumulated in high concentrations by marine algae, which are the origin of strong iodine fluxes into the coastal atmosphere which influence climatic processes, and dissolved iodine is considered a biophilic element in marine sediments. Iodine is central to thyroid function in vertebrates, with paramount implications for human health. Iodine can exist in a wide range of oxidation states and it features a diverse supramolecular chemistry. Iodine is amenable to several analytical techniques, and iodine compounds have found widespread use in organic synthesis. Elemental iodine is produced on an industrial scale and has found a wide range of applications in innovative materials, including semiconductors--in particular, in solar cells., (Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)
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- 2011
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3. ALTERATIONS IN THE PHYSICAL AND ENZYMIC PROPERTIES OF ALPHA-CHYMOTRYPSIN IN UREA AND GUANIDINIUM CHLORIDE.
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MARTIN CJ
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- Calcium Chloride, Chemical Phenomena, Chemistry, Chymotrypsin, Guanidine, Guanidines, Hydrogen-Ion Concentration, Research, Spectrophotometry, Urea
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- 1964
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4. Cr2+ solid solution in UO2 evidenced by advanced spectroscopy
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Hannah Smith, Luke T. Townsend, Ritesh Mohun, Théo Cordara, Martin C. Stennett, J. Frederick W. Mosselmans, Kristina Kvashnina, and Claire L. Corkhill
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Chemistry ,QD1-999 - Abstract
Chromia is an important additive used in uranium dioxide fuel fabrication, but its incorporation mechanism is still not fully understood. Here, the authors use X-ray absorption spectroscopy, including both near edge and extended fine structure regions, to resolve the local structure and valence state of chromium, as divalent, in uranium dioxide.
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- 2022
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5. Expanding the Solubility Parameter Method MOSCED to Pyridinium‑, Quinolinium‑, Pyrrolidinium‑, Piperidinium‑, Bicyclic‑, Morpholinium‑, Ammonium-, Phosphonium-, and Sulfonium-Based Ionic Liquids
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Pratik Dhakal, Anthony R. Weise, Martin C. Fritsch, Cassandra M. O’Dell, and Andrew S. Paluch
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Chemistry ,QD1-999 - Published
- 2020
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6. From Macro to Micro: Comparison of Imaging Techniques to Detect Vascular Network Formation in Left Ventricle Decellularized Extracellular Matrix Hydrogels
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Meng Zhang, Vasilena E. Getova, Francisco Drusso Martinez-Garcia, Theo Borghuis, Janette K. Burgess, and Martin C. Harmsen
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vascular network formation ,fluorescence microscopy ,confocal microscopy ,optical coherence tomography ,decellularized extracellular matrix hydrogels ,Science ,Chemistry ,QD1-999 ,Inorganic chemistry ,QD146-197 ,General. Including alchemy ,QD1-65 - Abstract
Background: Angiogenesis is a crucial process in physiological maintenance and tissue regeneration. To understand the contribution of angiogenesis, it is essential to replicate this process in an environment that reproduces the biochemical and physical properties which are largely governed by the extracellular matrix (ECM). We investigated vascularization in cardiac left ventricular ECM hydrogels to mimic post-myocardial repair. We set out to assess and compare different destructive and non-destructive methods, optical as well as non-optical, to visualize angiogenesis and associated matrix remodeling in myocardial ECM hydrogels. Methods: A total of 100,000, 300,000, and 600,000 Human Pulmonary Microvascular Endothelial Cells (HPMEC) were seeded in left ventricular cardiac ECM hydrogel in 48-well plates. After 1, 7, and 14 days of culture, the HPMEC were imaged by inverted fluorescence microscopy and 3D confocal laser scanning microscopy (Zeiss Cell Discoverer 7). In addition, cell-seeded ECM hydrogels were scanned by optical coherence tomography (OCT). Fixed and paraffin-embedded gels were thin-sectioned and assessed for ECM components via H&E, picrosirius red histochemical staining, and immunostaining for collagen type I. ImageJ-based densitometry was used to quantify vascular-like networks and GraphPad was used for statistical analyses. Results: Qualitative analyses were realized through fluoromicrographs obtained by the confocal laser scanning microscope which allowed us to visualize the extensive vascular-like networks that readily appeared at all seeding densities. Quantification of networks was only possible using fluoromicrographs from inverted microscopy. These showed that, after three days, the number of master junctions was seeding density-dependent. The resolution of optical coherence tomography was too low to distinguish between signals caused by the ECM and cells or networks, yet it did show that gels, irrespective of cells, were heterogeneous. Interestingly, (immuno)histochemistry could clearly distinguish between the cast cardiac-derived matrix and newly deposited ECM in the hydrogels. The H&E staining corroborated the presence of vascular-like network structures, albeit that sectioning inevitably led to the loss of 3D structure. Conclusions: Except for OCT, all methods had complementary merit and generated qualitative and quantitative data that allowed us to understand vascular network formation in organ-derived ECM hydrogels.
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- 2022
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7. Mode of Action of the Natural Product Allicin in a Plant Model: Influence on the Cytoskeleton and Subsequent Shift in Auxin Localization
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Ulrike Noll, Miriam Schreiber, Monika Hermanns, Christopher A. Mertes, Alan J. Slusarenko, and Martin C. H. Gruhlke
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allicin ,redox ,tradescantia ,arabidopsis ,cytoskeleton ,auxin ,Technology ,Engineering (General). Civil engineering (General) ,TA1-2040 ,Biology (General) ,QH301-705.5 ,Physics ,QC1-999 ,Chemistry ,QD1-999 - Abstract
Allicin is a defense substance produced by garlic cells when they are injured. It is a redox-active thiosulfinate showing redox-activity with a broad range of dose-dependent antimicrobial and biocidal activity. It is known that allicin efficiently oxidizes thiol-groups, and it has been described as a redox toxin because it alters the redox homeostasis in cells and triggers oxidative stress responses. Allicin can therefore be used as a model substance to investigate the action of thiol-specific prooxidants. In order to learn more about the effect of allicin on plants, we used pure synthetized allicin, and studied the influence of allicin on organelle movement in Tradescantia fluminensis as a cytoskeleton-dependent process. Furthermore, we investigated cytoplasmic streaming in sterile filaments of Tradescantia fluminensis, organelle movement using transgenic Arabidopsis with organelle-specifics GFP-tags, and effects on actin and tubulin in the cytoskeleton using GFP-tagged lines. Tubulin and actin were visualized by GFP-tagging in transgenic lines of Arabidopsis thaliana to visualize the influence of allicin on the cytoskeleton. Since auxin transport depends on recycling and turnover of the PIN protein involving cytoskeletal transport to and from the membrane localization sites, auxin distribution in roots was investigated using of transgenic PIN1–GFP, PIN3–GFP, DR5–GFP and DII–VENUS Arabidopsis reporter lines. Allicin inhibited cytoplasmic streaming in T. fluminensis, organelle movement of peroxi-somesperoxisomes, and the Golgi apparatus in a concentration-dependent manner. It also destroyed the correct root tip distribution of auxin, which probably contributed to the observed inhibition of root growth. These observations of the disruption of cytoskeleton-dependent transport processes in plant cells add a new facet to the mechanism of action of allicin as a redox toxin in cells.
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- 2022
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8. Effect of Prooxidative Natural Products: Comparison of the OSI1 (YKL071w) Promoter Luciferase Construct from Yeast with an Nrf2/Keap Reporter System
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Ivan Schlembach, Andreas Uebachs, Tim Caspers, Athanassios Fragoulis, Alan J. Slusarenko, and Martin C. H. Gruhlke
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Yap1p ,YKL071w ,luciferase ,allicin ,phenylethyl isothiocyanate ,allyl isothiocyanate ,Technology ,Engineering (General). Civil engineering (General) ,TA1-2040 ,Biology (General) ,QH301-705.5 ,Physics ,QC1-999 ,Chemistry ,QD1-999 - Abstract
The oxidative stress response (OSR) in yeast is under the control of oxidation-sensitive cysteines in the Yap1p transcription factor, and fusion of the Yap1p-dependent OS-induced promoter of the YKL071w gene (OSI1) to a luciferase coding sequence makes a sensitive reporter for OS induced by electrophiles. In mammalian cells, the OSR induced by electrophiles is coordinated in a mechanistically similar way via oxidation-sensitive cysteines in the kelch-like ECH-associated protein 1 (Keap1)– nuclear factor erythroid 2-related factor 2 / antioxidant response element ( Nrf2/ARE) system. Many electrophilic oxidants have already been independently shown to trigger both the Yap1 and Keap1 systems. Here, we investigated the responses of Yap1 and Keap1 reporters to sulforaphane (SFN), allyl isothiocyanate (AITC), phenylethyl isothiocyanate (PEITC), previously known to stimulate Keap1–Nrf2/ARE but not known to activate Yap1, and as a positive control, allicin, previously reported to stimulate both Yap1 and Nrf2. We have compared the reciprocal responsiveness of the respective reporter systems and show that the yeast reporter system can have predictive value for electrophiles that stimulate the mammalian Keap1–Nrf2/ARE system.
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- 2020
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9. Efficacy of Allicin against Plant Pathogenic Fungi and Unveiling the Underlying Mode of Action Employing Yeast Based Chemogenetic Profiling Approach
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Muhammad Sarfraz, Muhammad Jawad Nasim, Claus Jacob, and Martin C. H. Gruhlke
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allicin ,garlic ,antifungal activities ,haploinsufficiency screening ,yeast ,chemogenetic screening ,Technology ,Engineering (General). Civil engineering (General) ,TA1-2040 ,Biology (General) ,QH301-705.5 ,Physics ,QC1-999 ,Chemistry ,QD1-999 - Abstract
Allicin (diallylthiosulfinate) is the principal organosulfur compound present in freshly damaged garlic tissue which exhibits a wide range of biological actions including antibacterial, antifungal, antiviral and anticancer properties. The antifungal activities of allicin were investigated against plant pathogenic fungi of agriculture importance. Furthermore, a yeast genome haploinsufficiency screening was also employed to decipher the antifungal mode of action of allicin. Wildtype and 1152 yeast mutant strains (each deprived of one specific allele of an essential gene in a diploid strain) were screened against allicin. Allicin exhibited promising antifungal properties against all the tested plant pathogens. Haploinsufficiency screening revealed three hypersensitive yeast mutants with gene deletions coding for proteins involved in DNA replication, mitochondrial translation and chromatids cohesion. These processes play a vital role in the cell cycle, growth and viability of yeast cells. Taken together, the results of the present study unravel the excellent antifungal activities and mechanisms and modes of action of allicin. These findings also indicate the potential use of allicin as an alternative “green” fungicide (fumigant) in agriculture.
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- 2020
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10. Validation of Fenoterol to Study β2-Adrenoceptor Function in the Rat Urinary Bladder
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Zeynep Elif Yesilyurt, Ebru Arioglu-Inan, Betül R Erdogan, and Martin C. Michel
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Pharmacology ,Agonist ,Carbachol ,Urinary bladder ,Chemistry ,medicine.drug_class ,Antagonist ,General Medicine ,respiratory system ,Rat Urinary Bladder ,Muscarinic agonist ,medicine.anatomical_structure ,medicine ,Potency ,Fenoterol ,medicine.drug - Abstract
Fenoterol is a β2-adrenoceptor (AR)-selective agonist that is commonly used to investigate relaxation responses mediated by β2-AR in smooth muscle preparations. Some data have questioned this because fenoterol had low potency in the rat urinary bladder when a muscarinic agonist was used as a pre-contraction agent and because some investigators proposed that fenoterol may act in part via β3-AR. We designed the present study to investigate whether fenoterol is a proper pharmacological tool to study β2-AR-mediated relaxation responses in the rat urinary bladder. Firstly, we have compared the effect of pre-contraction agents on fenoterol potency and found that fenoterol potency was about 1.5 log units greater against KCl than carbachol (pEC50 7.19 ± 0.66 and 5.62 ± 1.09 of KCl and of carbachol, respectively). To test the selectivity of fenoterol, we have determined the effects of the β2-AR antagonist ICI 118,551 and the β3-AR antagonist L 748,337 on relaxation responses to fenoterol. While 300 nM L 748,337 had little effect on the potency of fenoterol (pEC50 6.56 ± 0.25 and 6.33 ± 0.61 in the absence and presence of L 748,337, respectively), the relaxation curve for fenoterol was right-shifted in the presence 300 nM ICI 118,551 (pEC50 5.03 ± 0.18). Thus, we conclude that fenoterol is a proper pharmacological tool to assess β2-AR-mediated responses in the rat urinary bladder and most likely in other smooth-muscle preparations containing multiple subtypes of the β-AR.
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- 2021
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11. Gold(III) Meets Azulene: A Class of [(tBuC∧N∧C)AuIII(azulenyl)] Pincer Complexes
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Daniel Eppel, Fabian Stuck, Frank Rominger, Petra Krämer, Patrick Cieslik, Lukas Eberle, Matthias Rudolph, Andreas Dreuw, Martin C. Dietl, Nils Oberhof, and A. Stephen K. Hashmi
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Inorganic Chemistry ,Class (set theory) ,chemistry.chemical_compound ,Gold iii ,Chemistry ,Organic Chemistry ,Physical and Theoretical Chemistry ,Azulene ,Medicinal chemistry ,Pincer movement - Published
- 2021
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12. The proposed Silicate-Sulfuric Acid Process: Mineral processing for In Situ Resource Utilization (ISRU)
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Eleanor K. Sansom, Patrick Shober, Benjamin A. D. Hartig, Martin C. Towner, Seamus Anderson, and Hadrien A. R. Devillepoix
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Earth and Planetary Astrophysics (astro-ph.EP) ,Waste management ,FOS: Physical sciences ,Aerospace Engineering ,chemistry.chemical_element ,In situ resource utilization ,Sulfuric acid ,Sulfur ,Space Physics (physics.space-ph) ,Silicate ,Sulfide minerals ,chemistry.chemical_compound ,Physics - Space Physics ,chemistry ,Silicate minerals ,Environmental science ,Astrophysics - Instrumentation and Methods for Astrophysics ,Instrumentation and Methods for Astrophysics (astro-ph.IM) ,Volatiles ,Mineral processing ,Astrophysics - Earth and Planetary Astrophysics - Abstract
Volatile elements and compounds found in extra-terrestrial environments are often the target of In Situ Resource Utilization (ISRU) studies. Although water and hydroxide are most commonly the focus of these studies as they can be used for propellant and human consumption; we instead focus on the possible exploitation of sulfur and how it could be utilized to produce building materials on the Moon, Mars and Asteroids. We describe the physical and chemical pathways for extracting sulfur from native sulfide minerals, manufacturing sulfuric acid in situ, and using the produced acid to dissolve native silicate minerals. The final products of this process, which we call the Silicate-Sulfuric Acid Process (SSAP), include iron metal, silica, oxygen and metal oxides, all of which are crucial in the scope of a sustainable, space-based economy. Although our proposed methodology requires an initial investment of water, oxygen, and carbon dioxide, we show that all of these volatiles are recovered and reused in order to repeat the process. We calculate the product yield from this process if it were enacted on the lunar highlands, lunar mare, Mars, as well as an array of asteroid types.
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- 2021
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13. Access to Unsymmetrically Substituted Diaryl Gold N‐Acyclic Carbene (NAC) and N‐Heterocyclic Carbene (NHC) Complexes via the Isonitrile Route
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Matthias Rudolph, Martin C. Dietl, Vanessa Claus, Arne Meister, Jonas F. Huber, Leon K. Paschai Darian, Daniel Ehjeij, Frank Rominger, A. Stephen K. Hashmi, and Vanessa Vethacke
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chemistry.chemical_compound ,Chemistry ,General Chemistry ,Medicinal chemistry ,Carbene - Published
- 2021
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14. A Selection of Macrocyclic Peptides That Bind STING From an mRNA‐Display Library With Split Degenerate Codons
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Dasa Lipovsek, Andrew E Douglas, Mary J. Harner, Michael A. Poss, Fei Yu, Chi-Wang Lin, Joanna F. Swain, Ving G. Lee, Virginie Lafont, and Martin C. Wright
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Stereochemistry ,Peptides | Hot Paper ,selection ,Sequence (biology) ,Peptides, Cyclic ,Catalysis ,chemistry.chemical_compound ,Peptide Library ,Cyclic AMP ,Humans ,mRNA display ,Amino Acid Sequence ,RNA, Messenger ,Amino Acids ,Codon ,Cyclic GMP ,codon expansion ,chemistry.chemical_classification ,Methionine ,Communication ,Membrane Proteins ,General Chemistry ,General Medicine ,genetic reprograming ,Communications ,eye diseases ,Amino acid ,Dissociation constant ,Kinetics ,Sting ,chemistry ,Chemical diversity ,peptides ,Alphabet ,Genetic Engineering ,Dimerization - Abstract
Recent improvements in mRNA display have enabled the selection of peptides that incorporate non‐natural amino acids, thus expanding the chemical diversity of macrocycles beyond what is accessible in nature. Such libraries have incorporated non‐natural amino acids at the expense of natural amino acids by reassigning their codons. Here we report an alternative approach to expanded amino‐acid diversity that preserves all 19 natural amino acids (no methionine) and adds 6 non‐natural amino acids, resulting in the highest sequence complexity reported to date. We have applied mRNA display to this 25‐letter library to select functional macrocycles that bind human STING, a protein involved in immunoregulation. The resulting STING‐binding peptides include a 9‐mer macrocycle with a dissociation constant (K D) of 3.4 nM, which blocks binding of cGAMP to STING and induces STING dimerization. This approach is generalizable to expanding the amino‐acid alphabet in a library beyond 25 building blocks., In vitro selection of macrocyclic peptides from a library that uses a 25‐amino‐acid alphabet has allowed the identification of peptides that block binding of human STING to its natural ligand and induce dimerization of STING monomers. Our method splits multiple degenerate codons and reassigns them to non‐natural amino acids.
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- 2021
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15. Structural, Optical, and Electronic Properties of Two Quaternary Chalcogenide Semiconductors: Ag2SrSiS4 and Ag2SrGeS4
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Jon-Paul Sun, Garrett C. Wessler, Tianlin Wang, Volker Blum, Martin C Fischer, Yuheng Liao, and David B. Mitzi
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Band gap ,Chemistry ,business.industry ,Chalcogenide ,Inorganic Chemistry ,Tetragonal crystal system ,Crystallography ,chemistry.chemical_compound ,Semiconductor ,Impurity ,Density functional theory ,Physical and Theoretical Chemistry ,business ,Electronic properties - Abstract
Quaternary chalcogenide materials have long been a source of semiconductors for optoelectronic applications. Recent studies on I2-II-IV-X4 (I = Ag, Cu, Li; II = Ba, Sr, Eu, Pb; IV = Si, Ge, Sn; X = S, Se) materials have shown particular versatility and promise among these compounds. These semiconductors take advantage of a diverse bonding scheme and chemical differences among cations to target a degree of antisite defect resistance. Within this set of compounds, the materials containing both Ag and Sr have not been experimentally studied and leave a gap in the full understanding of the family. Here, we have synthesized powders and single crystals of two Ag- and Sr-containing compounds, Ag2SrSiS4 and Ag2SrGeS4, each found to form in the tetragonal I42m structure of Ag2BaGeS4. During the synthesis targeting the title compounds, two additional materials, Ag2Sr3Si2S8 and Ag2Sr3Ge2S8, have also been identified. These cubic compounds represent impurity phases during the synthesis of Ag2SrSiS4 and Ag2SrGeS4. We show through hybrid density functional theory calculations that Ag2SrSiS4 and Ag2SrGeS4 have highly dispersive band-edge states and indirect band gaps, experimentally measured as 2.08(1) and 1.73(2) eV, respectively. Second-harmonic generation measurements on Ag2SrSiS4 and Ag2SrGeS4 powders show frequency-doubling capabilities in the near-infrared range.
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- 2021
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16. High stretch induces endothelial dysfunction accompanied by oxidative stress and actin remodeling in human saphenous vein endothelial cells
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Martin C. Harmsen, Ayumi Aurea Miyakawa, L A O Dallan, Nikita P. Patil, Joao Carlos Ribeiro-Silva, J. Jack Lee, José Eduardo Krieger, Thais Girão-Silva, Aaron B. Baker, Miriam H. Fonseca-Alaniz, and Restoring Organ Function by Means of Regenerative Medicine (REGENERATE)
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0301 basic medicine ,Cell biology ,THP-1 Cells ,Science ,Cardiology ,030204 cardiovascular system & hematology ,medicine.disease_cause ,Article ,03 medical and health sciences ,0302 clinical medicine ,medicine ,Humans ,Saphenous Vein ,Endothelial dysfunction ,Cell adhesion ,chemistry.chemical_classification ,Reactive oxygen species ,Multidisciplinary ,Actin remodeling ,Endothelial Cells ,Cofilin ,medicine.disease ,Cardiovascular biology ,Actins ,Endothelial stem cell ,Oxidative Stress ,030104 developmental biology ,medicine.anatomical_structure ,chemistry ,Medicine ,Stress, Mechanical ,Reactive Oxygen Species ,Oxidative stress ,Artery ,Cell signalling - Abstract
The rate of the remodeling of the arterialized saphenous vein conduit limits the outcomes of coronary artery bypass graft surgery (CABG), which may be influenced by endothelial dysfunction. We tested the hypothesis that high stretch (HS) induces human saphenous vein endothelial cell (hSVEC) dysfunction and examined candidate underlying mechanisms. Our results showed that in vitro HS reduces NO bioavailability, increases inflammatory adhesion molecule expression (E-selectin and VCAM1) and THP-1 cell adhesion. HS decreases F-actin in hSVECs, but not in human arterial endothelial cells, and is accompanied by G-actin and cofilin’s nuclear shuttling and increased reactive oxidative species (ROS). Pre-treatment with the broad-acting antioxidant N-acetylcysteine (NAC) supported this observation and diminished stretch-induced actin remodeling and inflammatory adhesive molecule expression. Altogether, we provide evidence that increased oxidative stress and actin cytoskeleton remodeling play a role in HS-induced saphenous vein endothelial cell dysfunction, which may contribute to predisposing saphenous vein graft to failure.
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- 2021
17. A pH-ciklizálás jelentősége az amelogenesisben
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Beáta Kerémi, Róbert Rácz, Gábor Varga, Martin C. Steward, and Pamela DenBesten
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Enamel paint ,Tight junction ,Enamel defects ,Chemistry ,General Medicine ,Amelogenesis ,Matrix (biology) ,Cell biology ,stomatognathic system ,visual_art ,visual_art.visual_art_medium ,Secretion ,Semipermeable membrane ,Ameloblast - Abstract
The process of amelogenesis is well understood at the histomorphological level, but the regulation of crystal formation and the underlying molecular mechanisms are still largely unknown. Ameloblast cells derived from the oral epithelium regulate enamel maturation. In addition to the secretion of matrix proteins and the transport of minerals, pH regulation is also essential as the formation of hydroxyapatite crystals generates large quantities of H+ ions, which must be neutralized by the secretion of HCO3−. During the maturation phase, the phenomenon of pH cycling is of paramount importance, during which a rearrangement of tight-junctions can also be observed. Genetic or environmental impairment of transport and regulatory processes (e.g. dental fluorosis) leads to the development of enamel defects. To explore these processes, we have developed an in vitro model suitable for functional studies. Central elements of this model are that differentiated ameloblast-derived cells cultured on a permeable membrane express ameloblast-specific protein markers, form tight junctions, become functionally polarized, and are capable of vectorial HCO3− secretion. The results of our own experimental work contribute to a better understanding of the molecular mechanism of pH cycling of ameloblast cells.
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- 2021
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18. Use of WetSEM® capsules for convenient multimodal scanning electron microscopy, energy dispersive X-ray analysis, and micro Raman spectroscopy characterisation of technetium oxides
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Neil C. Hyatt, Daniel J. Bailey, Jong Heo, and Martin C. Stennett
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Materials science ,Scanning electron microscope ,Health, Toxicology and Mutagenesis ,Instrumentation ,chemistry.chemical_element ,Nanotechnology ,02 engineering and technology ,Technetium ,01 natural sciences ,Analytical Chemistry ,law.invention ,symbols.namesake ,law ,0103 physical sciences ,Radiology, Nuclear Medicine and imaging ,X ray analysis ,Spectroscopy ,010302 applied physics ,Public Health, Environmental and Occupational Health ,021001 nanoscience & nanotechnology ,Laser ,Pollution ,Micro raman spectroscopy ,Nuclear Energy and Engineering ,chemistry ,symbols ,0210 nano-technology ,Raman spectroscopy - Abstract
SEM–EDX and Raman spectroscopy analysis of radioactive compounds is often restricted to dedicated instrumentation, within radiological working areas, to manage the hazard and risk of contamination. Here, we demonstrate application of WetSEM® capsules for containment of technetium powder materials, enabling routine multimodal characterisation with general user instrumentation, outside of a controlled radiological working area. The electron transparent membrane of WetSEM® capsules enables SEM imaging of submicron non-conducting technetium powders and acquisition of Tc Lα X-ray emission, using a low cost desktop SEM–EDX system, as well as acquisition of good quality μ-Raman spectra using a 532 nm laser.
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- 2021
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19. Postextubation Respiratory Support
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Martin C. J. Kneyber and Critical care, Anesthesiology, Peri-operative and Emergency medicine (CAPE)
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Oxygen inhalation therapy ,chemistry.chemical_element ,Airway Extubation ,Critical Care and Intensive Care Medicine ,Oxygen ,medicine ,Intubation, Intratracheal ,Prevalence ,Humans ,Child ,Retrospective Studies ,business.industry ,Intratracheal/adverse effects ,Oxygen Inhalation Therapy ,High flow oxygen ,Retrospective cohort study ,medicine.disease ,Respiratory support ,Intubation, Intratracheal/adverse effects ,chemistry ,Bronchiolitis ,Anesthesia ,Pediatrics, Perinatology and Child Health ,business ,Intubation - Published
- 2021
20. Epitaxial Guidance of Adamantyl-Substituted Polythiophenes by Self-Assembled Monolayers
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Dominik Farka, Martin Ciganek, Dominik Veselý, Lukáš Kalina, and Jozef Krajčovič
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Chemistry ,QD1-999 - Published
- 2024
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21. Synthesis and characterisation of HIP Ca0.80Ce0.20ZrTi1.60Cr0.40O7 zirconolite and observations of the ceramic–canister interface
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Amber R. Mason, Shi-Kuan Sun, Merve Kuman, Laura J. Gardner, Claire L. Corkhill, Ewan R. Maddrell, Lewis R. Blackburn, Max R. Cole, Daniel J. Bailey, Neil C. Hyatt, and Martin C. Stennett
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Zirconolite ,Materials science ,Mechanical Engineering ,Oxide ,Analytical chemistry ,Condensed Matter Physics ,Ceramic matrix composite ,XANES ,chemistry.chemical_compound ,chemistry ,Absorption edge ,Mechanics of Materials ,Phase (matter) ,visual_art ,visual_art.visual_art_medium ,General Materials Science ,Ceramic ,Perovskite (structure) - Abstract
A sample of zirconolite with nominal composition Ca0.80Ce0.20ZrTi1.60Cr0.40O7was processed via Hot Isostatic Pressing (HIP), with a dwell temperature and pressure of 1320 °C/100 MPa maintained for 4 h. The produced wasteform was characterised by powder XRD, SEM–EDS, Ce L3and Cr K-edge XANES. A significant portion of the Ce inventory did not fully partition within the zirconolite phase, instead remaining as CeO2within the microstructure. Inspection of the stainless steel–ceramic interface detailed the presence of an interaction region dominated by a Cr-rich oxide layer. No significant Cr or Fe migration was observed, although a greater concentration of perovskite was observed at the periphery, relative to the bulk ceramic matrix. The X-ray absorption features of Cr remained analogous with Cr3+accommodation within TiO6octahedra in the zirconolite matrix. The absorption edge of Ce was comprised of contributions from zirconolite-2M and unincorporated CeO2, with an average oxidation state of Ce3.9+. As zirconolite-2M accounted for > 92 wt% of the overall phase assemblage, it is clear that the dominant oxidation state of Ce in this phase was Ce4+.Graphic abstract
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- 2021
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22. Au–Ag Bimetallic Catalysis: 3‐Alkynyl Benzofurans from Phenols via Tandem C−H Alkynylation/Oxy‐Alkynylation
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A. Stephen K. Hashmi, Long Hu, Martin C. Dietl, Frank Rominger, Chunyu Han, and Matthias Rudolph
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Tandem ,010405 organic chemistry ,Communication ,Alkynylation ,Context (language use) ,General Chemistry ,010402 general chemistry ,Triple bond ,01 natural sciences ,Redox ,Combinatorial chemistry ,Communications ,Catalysis ,0104 chemical sciences ,Benzofuran Synthesis ,chemistry.chemical_compound ,Phenols ,Catalytic cycle ,chemistry ,Functional group ,Au–Ag bimetallic catalysis ,Bimetallic strip ,Benzofurans - Abstract
The development of new methodologies enabling a facile access to valuable heterocyclic frameworks still is an important subject of research. In this context, we describe a dual catalytic cycle merging C−H alkynylation of phenols and oxy‐alkynylation of the newly introduced triple bond by using a unique redox property and the carbophilic π acidity of gold. Mechanistic studies support the participation of a bimetallic gold–silver species. The one‐pot protocol offers a direct, simple, and regio‐specific approach to 3‐alkynyl benzofurans from readily available phenols. A broad range of substrates, including heterocycles, is transferred with excellent functional group tolerance. Thus, this methodology can be used for the late‐stage incorporation of benzofurans., A mild and general synthesis of 3‐alkynylbenzofurans from readily available phenols by Au–Ag bimetallic catalysis has been developed. Importantly, this also advances our mechanistic understanding of the “silver effect” in gold redox chemistry.
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- 2021
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23. Au‐Ag‐Bimetallkatalyse: 3‐Alkinylbenzofurane aus Phenolen durch Tandem‐C‐H‐Alkinylierung/Oxyalkinylierung
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Frank Rominger, Chunyu Han, Long Hu, Martin C. Dietl, A. Stephen K. Hashmi, and Matthias Rudolph
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Chemistry ,General Medicine - Published
- 2021
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24. Development and optimisation of simulated salivary fluid for biorelevant oral cavity dissolution
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Sally Gittings, Jong Bong Lee, Alessandro Iachelini, Clive J. Roberts, Joanne Bennett, Joseph Ali, Pavel Gershkovich, Martin C. Garnett, and Anne Cram
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Saliva ,Therapeutic action ,Swine ,Chemistry, Pharmaceutical ,Administration, Oral ,Pharmaceutical Science ,02 engineering and technology ,Oral cavity ,030226 pharmacology & pharmacy ,03 medical and health sciences ,0302 clinical medicine ,Drug Development ,Animals ,Humans ,Surface Tension ,Dissolution testing ,Dissolution ,Mouth ,Chromatography ,Chemistry ,Mucins ,General Medicine ,Hydrogen-Ion Concentration ,021001 nanoscience & nanotechnology ,Drug Liberation ,Solubility ,Salivary Proteins ,Drug release ,Cattle ,0210 nano-technology ,Biotechnology - Abstract
Drug release within the oral cavity can be of paramount importance for formulations that are designed for specific purposes such as taste-masking, faster onset of therapeutic action, localization of treatment or avoidance of first-pass metabolism. Preclinical methods for assessment of dissolution in the oral cavity are necessary for design and development of these formulation but currently there is no consensus on what variables should be defined to achieve biorelevance in these tests. In this study, biorelevant simulated salivary fluids (SSFs) that can be uniformly applied for oral cavity dissolution testing were developed. Unstimulated saliva (US) SSF and stimulated saliva (SS) SSF were separately developed since the two states significantly differ. Physicochemical properties including pH, buffer capacity, surface tension and viscosity were assessed during development and optimised to mimic human saliva (HS). In order to account for the salivary proteins in HS, use of bovine submaxillary mucin (BSM) and porcine gastric mucin (PGM) in SSFs was evaluated. Following optimisation of the SSFs, biorelevance of the developed SSFs to HS was assessed by their comparative physicochemical properties as well as dissolution profiles of three diverse model compounds (sildenafil citrate, efavirenz, and caffeine) which showed comparable profiles between the SSFs and HS. This work addresses the lack of uniformed biorelevant dissolution media for oral cavity dissolution studies and provides a basis for standardised dissolution tests that provide consistency and harmonisation in future oral cavity dissolution studies. We envisage that this will have a positive impact on the development of new medicines that require functionality in the oral cavity.
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- 2021
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25. Synthesis, structure, and characterization of the thorium zirconolite CaZr 1‐x Th x Ti 2 O 7 system
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Shi-Kuan Sun, Lewis R. Blackburn, Laura J. Gardner, Martin C. Stennett, Neil C. Hyatt, Claire L. Corkhill, and Ewan R. Maddrell
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010302 applied physics ,Zirconolite ,Materials science ,Analytical chemistry ,Pyrochlore ,Thorium ,chemistry.chemical_element ,02 engineering and technology ,engineering.material ,021001 nanoscience & nanotechnology ,01 natural sciences ,chemistry ,Hot isostatic pressing ,Phase (matter) ,visual_art ,0103 physical sciences ,Materials Chemistry ,Ceramics and Composites ,visual_art.visual_art_medium ,engineering ,Composition (visual arts) ,Ceramic ,0210 nano-technology ,Perovskite (structure) - Abstract
A series of zirconolite ceramics with composition CaZr1‐xThxTi2O7 (Δx = 0.10) were reactively sintered at 1350 ˚C for 20 h, in air (0 ≤ x ≤ 0.60) and 5% H2/N2 (0 ≤ x ≤ 0.40). A sample with composition corresponding to x = 0.20 was also produced by hot isostatic pressing (HIP) at 1300 ˚C and 100 MPa for 4 h. Th4+ immobilisation was most readily achieved under oxidising conditions, with Th4+ preferentially incorporated within a pyrochlore‐structured phase in the range 0.10 ≤ x ≤ 0.50, yet formation of the zirconolite‐4M polytype was not observed. We report the novel synthesis of single phase pyrochlore with nominal composition CaZr0.40Th0.60Ti2O7 when targeting x = 0.60. Th4+ incorporation under reducing conditions produced a secondary Th‐bearing perovskite, comprising 24.2 ± 0.6 wt. % of the phase assemblage when targeting x = 0.40, alongside 8.8 ± 0.3 wt. % undigested ThO2. Under reducing conditions, powder XRD data were consistent with zirconolite adopting the 3T polytype structure. The sample produced by HIP presented a non‐equilibrium phase assemblage, yielding a major phase of zirconolite‐2M alongside accessory Th4+ bearing phases ThTi2O6, ThO2 and perovskite. These data highlight the efficacy of Th4+ as a Pu4+ surrogate, with implications for the formation of Zr‐stabilised Th‐pyrochlore phases as matrices for waste with elevated Th4+ content.
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- 2021
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26. Frequency and anatomic distribution of arterial obstructions in patients with vasculogenic erectile dysfunction not responding to intracavernous prostaglandin
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Martin C. Schumacher, Nicolas Diehm, Jan Schönhofen, Heinz Schönhofen, Hak-Hong Keo, Christoph Kalka, Vignes Mohan, Giuseppe Sangiorgi, and Jonas Knöchel
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Male ,Venous leak ,medicine.medical_specialty ,arterial obstruction ,medicine.medical_treatment ,Prostaglandin ,Penile artery ,030204 cardiovascular system & hematology ,Settore MED/11 ,03 medical and health sciences ,chemistry.chemical_compound ,0302 clinical medicine ,Erectile Dysfunction ,Penis ,Humans ,Middle Aged ,Penile Erection ,Prostaglandins ,erectile dysfunction ,intracavernous ,prostaglandin ,vasculogenic ,Aged ,Alprostandyl ,medicine.artery ,Angioplasty ,Internal medicine ,Medicine ,Internal pudendal artery ,Alprostadil ,030219 obstetrics & reproductive medicine ,business.industry ,Ultrasound ,medicine.disease ,Erectile dysfunction ,medicine.anatomical_structure ,chemistry ,Cohort ,Cardiology ,Cardiology and Cardiovascular Medicine ,business - Abstract
Summary: Background: The extent of arterial disease in patients with erectile dysfunction (ED) non-responsive to intracavernosal injection of Alprostadil is of importance for therapeutic options. However, published evidence, in particular angiographically validated is scarce. Here we investigated arterial lesion patterns in this specific patient cohort by selective angiography. Patients and methods: A cohort of 239 patients received a clinical and duplex-sonographic workup for ED of suspected vascular origin. Duplex ultrasound of the cavernosal arteries was performed after intracavernosal injection of 10 μg Alprostadil. Consequently, standardized workup included grading of the erectile and determination of peak systolic velocity (PSV) and end-diastolic velocity (EDV) in both cavernosal arteries. PSV-values below 30 cm/sec indicated reduced arterial flow, whereas EDV-values above 15 cm/sec indicated a venous leak of the pudendal veins. All patients with suspected arterial ED based on duplex sonography underwent contrast-enhanced computed tomography. Endovascular therapy was carried out in ED patients not responsive or with significant side effects to PDE-5-inhibitors or Alprostadil by selective angiographic depiction of erection-related arteries. Results: 54 patients with a mean age of 61.2 (±9.8) years underwent angioplasty of erectionr elated arteries. Out of these 48/54 (89%) patients presented with an erection considered insufficient for penetration (E0-E3) subsequent to intracavernous application of 10 μg Alprostadil. 14/48 (29%) patients had bilateral arterial obstructions and 34/48 (71%) had unilateral disease. Commonly affected was the internal pudendal artery (n = 31, 65%), followed closely by the common penile artery (n = 30, 64%). The least affected arteries were the dorsal penile (n = 6, 13%), hypogastric (n = 4, 8%), common iliac (n = 4, 8%), cavernosal (n = 4, 8%), and inferior gluteal (n = 1, 2%) arteries. Conclusions: Arterial obstructions amenable to endovascular revascularization are frequent in patients non-responsive to intracavernosal prostaglandin administration. Therapeutic strategies in ED patients non-responsive to conservative measures should therefore consider endovascular treatment opportunities.
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- 2021
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27. Review of zirconolite crystal chemistry and aqueous durability
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Lewis R. Blackburn, Laura J. Gardner, Martin C. Stennett, Neil C. Hyatt, Shi-Kuan Sun, Claire L. Corkhill, and Daniel J. Bailey
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010302 applied physics ,Zirconolite ,Materials science ,Aqueous solution ,Crystal chemistry ,Metallurgy ,chemistry.chemical_element ,02 engineering and technology ,021001 nanoscience & nanotechnology ,01 natural sciences ,Durability ,Industrial and Manufacturing Engineering ,Plutonium ,chemistry ,visual_art ,0103 physical sciences ,Ceramics and Composites ,visual_art.visual_art_medium ,Ceramic ,0210 nano-technology - Abstract
Zirconolite (CaZrTi2O7) has been identified as a candidate ceramic wasteform for the immobilisation and disposal of Pu inventories, for which there is no foreseen future use. Here, we provide an ov...
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- 2021
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28. The thermal decomposition of studtite: analysis of the amorphous phase
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Neil C. Hyatt, Nathan B.A. Thompson, Victoria L. Frankland, Martin C. Stennett, Matthew R. Gilbert, Joshua W. G. Bright, and David Read
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Materials science ,Health, Toxicology and Mutagenesis ,010402 general chemistry ,010502 geochemistry & geophysics ,01 natural sciences ,Analytical Chemistry ,law.invention ,symbols.namesake ,chemistry.chemical_compound ,law ,Radiology, Nuclear Medicine and imaging ,Calcination ,Spectroscopy ,0105 earth and related environmental sciences ,Thermal decomposition ,Public Health, Environmental and Occupational Health ,Uranyl ,Pollution ,XANES ,0104 chemical sciences ,Amorphous solid ,Nuclear Energy and Engineering ,chemistry ,Studtite ,symbols ,Physical chemistry ,Raman spectroscopy ,Schoepite - Abstract
Studtite is known to exist at the back-end of the nuclear fuel cycle as an intermediate phase formed in the reprocessing of spent nuclear fuel. In the thermal decomposition of studtite, an amorphous phase is obtained at calcination temperatures between 200 and 500 °C. This amorphous compound, referred to elsewhere in the literature as U2O7, has been characterised by analytical spectroscopic methods. The local structure of the amorphous compound has been found to contain uranyl bonding by X-ray absorption near edge (XANES), Fourier transform infrared and Raman spectroscopy. Changes in bond distances in the uranyl group are discussed with respect to studtite calcination temperature. The reaction of the amorphous compound with water to form metaschoepite is also discussed and compared with the structure of schoepite and metaschoepite by X-ray diffraction. A novel schematic reaction mechanism for the thermal decomposition of studtite is proposed.
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- 2021
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29. A Rubisco-binding protein is required for normal pyrenoid number and starch sheath morphology in Chlamydomonas reinhardtii
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Alan K. Itakura, Leif J. Pallesen, Lianyong Wang, Oliver D Caspari, Robyn Roth, Weronika Patena, Alistair J. McCormick, Howard Griffiths, Kher Xing Chan, Ursula Goodenough, Nicky Atkinson, Martin C. Jonikas, Gregory Reeves, Chan, Kher Xing [0000-0002-0236-6378], Griffiths, Howard [0000-0002-3009-6563], Jonikas, Martin C [0000-0002-9519-6055], and Apollo - University of Cambridge Repository
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0106 biological sciences ,Rubisco ,Starch ,Ribulose-Bisphosphate Carboxylase ,carbon fixation ,Chlamydomonas reinhardtii ,01 natural sciences ,Pyrenoid ,Carbon Cycle ,03 medical and health sciences ,chemistry.chemical_compound ,Organelle ,Plastids ,Plant Proteins ,030304 developmental biology ,0303 health sciences ,Multidisciplinary ,biology ,Chemistry ,starch ,Chlamydomonas ,RuBisCO ,food and beverages ,Cell Biology ,Biological Sciences ,biology.organism_classification ,Carbon ,Cell biology ,Chloroplast ,Phenotype ,PNAS Plus ,pyrenoid ,Mutation ,biology.protein ,phase separation ,Carrier Proteins ,010606 plant biology & botany ,Starch binding - Abstract
Significance Many cellular structures are assembled via phase separation, forming liquid-like droplets in a manner analogous to oil in water. How can the cell control whether there is 1 droplet or many? Here, we provide insights into this question by studying the pyrenoid, an algal liquid-like organelle that mediates a substantial portion of global CO2 fixation. Whereas most algae have just 1 pyrenoid, we characterize a mutant that has approximately 10 pyrenoids per cell. Our results suggest a model where imposing an increased surface area on the liquid-like pyrenoid matrix favors the formation of multiple pyrenoids, with a concomitant loss of photosynthetic efficiency. Our findings advance our basic understanding of the biogenesis of the pyrenoid and of phase-separated organelles in general., A phase-separated, liquid-like organelle called the pyrenoid mediates CO2 fixation in the chloroplasts of nearly all eukaryotic algae. While most algae have 1 pyrenoid per chloroplast, here we describe a mutant in the model alga Chlamydomonas that has on average 10 pyrenoids per chloroplast. Characterization of the mutant leads us to propose a model where multiple pyrenoids are favored by an increase in the surface area of the starch sheath that surrounds and binds to the liquid-like pyrenoid matrix. We find that the mutant’s phenotypes are due to disruption of a gene, which we call StArch Granules Abnormal 1 (SAGA1) because starch sheath granules, or plates, in mutants lacking SAGA1 are more elongated and thinner than those of wild type. SAGA1 contains a starch binding motif, suggesting that it may directly regulate starch sheath morphology. SAGA1 localizes to multiple puncta and streaks in the pyrenoid and physically interacts with the small and large subunits of the carbon-fixing enzyme Rubisco (ribulose-1,5-bisphosphate carboxylase/oxygenase), a major component of the liquid-like pyrenoid matrix. Our findings suggest a biophysical mechanism by which starch sheath morphology affects pyrenoid number and CO2-concentrating mechanism function, advancing our understanding of the structure and function of this biogeochemically important organelle. More broadly, we propose that the number of phase-separated organelles can be regulated by imposing constraints on their surface area.
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- 2019
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30. Low-Temperature Nitridation of Fe3O4 by Reaction with NaNH2
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Claire L. Corkhill, Neil C. Hyatt, Sarah E. O’Sullivan, Martin C. Stennett, Shi-Kuan Sun, Feihong Chen, Sebastian M. Lawson, and Yuji Masubuchi
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Reaction mechanism ,Thermogravimetric analysis ,Oxide ,Nitride ,Chemical synthesis ,law.invention ,Inorganic Chemistry ,chemistry.chemical_compound ,Chemical engineering ,chemistry ,law ,Phase (matter) ,Yield (chemistry) ,Physical and Theoretical Chemistry ,Crystallization - Abstract
Low-temperature soft chemical synthesis routes to transition-metal nitrides are of interest as an alternative to conventional high-temperature ammonolysis reactions involving large volumes of chemotoxic NH3 gas. One such method is the reaction between metal oxides and NaNH2 at ca. 200 °C to yield the counterpart nitrides; however, there remains uncertainty regarding the reaction mechanism and product phase assemblage (in particular, noncrystalline components). Here, we extend the chemical tool box and mechanistic understanding of such reactions, demonstrating the nitridation of Fe3O4 by reaction with NaNH2 at 170–190 °C, via a pseudomorphic reaction. The more reduced Fe3O4 precursor enabled nitride formation at lower temperatures than the previously reported equivalent reaction with Fe2O3. The product phase assemblage, characterized by X-ray diffraction, thermogravimetric analysis, and 57Fe Mossbauer spectroscopy, comprised 49–59 mol % e-Fe2+xN, accompanied by 29–39 mol % FeO1–xNx and 8–14 mol % γ″-FeN. The oxynitride phase was apparently noncrystalline in the recovered product but could be crystallized by heating at 180 °C. Although synthesis of transition-metal nitrides is achieved by reaction of the counterpart oxide with NaNH2, it is evident from this investigation that the product phase assemblage may be complex, which could prove a limitation if the objective is to produce a single-phase product with well-defined electrical, magnetic, or other physical properties for applications. However, the significant yield of the FeO1–xNx oxynitride phase identified in this study opens the possibility for the synthesis of metastable oxynitride phases in high yield, by reaction of a metal oxide substrate with NaNH2, with either careful control of H2O concentration in the system or postsynthetic hydrolysis and crystallization.
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- 2021
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31. Model‐based meta‐analysis of the time to first acute urinary retention or benign prostatic hyperplasia‐related surgery in patients with moderate or severe symptoms
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Oscar Della Pasqua, Matthias Oelke, Chandrashekhar Chavan, Martin C. Michel, Michael J. Manyak, Claus G. Roehrborn, Juan Manuel Palacios-Moreno, and Salvatore D'Agate
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Male ,medicine.medical_specialty ,disease‐modifying properties ,Combination therapy ,Prostatic Hyperplasia ,Placebo ,030226 pharmacology & pharmacy ,03 medical and health sciences ,chemistry.chemical_compound ,0302 clinical medicine ,baseline risk factors ,Lower urinary tract symptoms ,Tamsulosin ,Humans ,Medicine ,Pharmacology (medical) ,lower urinary tract symptoms ,030212 general & internal medicine ,acute urinary retention ,Pharmacology ,benign prostatic hyperplasia ,dutasteride ,Sulfonamides ,business.industry ,Urinary retention ,Hazard ratio ,Original Articles ,Urinary Retention ,medicine.disease ,Dutasteride ,Surgery ,Treatment Outcome ,chemistry ,Azasteroids ,tamsulosin ,Original Article ,Drug Therapy, Combination ,International Prostate Symptom Score ,medicine.symptom ,business ,time‐to‐event modelling ,medicine.drug - Abstract
Aims Combination therapy of 5α‐reductase inhibitor and α‐blocker is a guideline‐endorsed therapeutic approach for patients with moderate‐to‐severe lower urinary tract symptoms or benign prostatic hyperplasia (LUTS/BPH) who are at risk of disease progression. We aimed to disentangle the contribution of clinical and demographic baseline characteristics affecting the risk of acute urinary retention or BPH‐related surgery (AUR/S) from the effect of treatment with drugs showing symptomatic and disease‐modifying properties. Methods A time‐to‐event model was developed using pooled data from patients (n = 10 238) enrolled into six clinical studies receiving placebo, tamsulosin, dutasteride or tamsulosin‐dutasteride combination therapy. A parametric hazard function was used to describe the time to first AUR/S. Covariate model building included the assessment of relevant clinical and demographic factors on baseline hazard. Predictive performance was evaluated by graphical and statistical methods. Results An exponential hazard model best described the time to first AUR/S in this group of patients. Baseline International Prostate Symptom Score, prostate‐specific antigen, prostate volume and maximum urine flow were identified as covariates with hazard ratio estimates of 1.04, 1.08, 1.01 and 0.91, respectively. Dutasteride monotherapy and tamsulosin‐dutasteride combination therapy resulted in a significant reduction in the baseline hazard (56.8% and 66.4%, respectively). By contrast, the effect of tamsulosin did not differ from placebo. Conclusions Our analysis showed the implications of disease‐modifying properties of dutasteride and tamsulosin‐dutasteride combination therapy for the risk of AUR/S. It also elucidated the contribution of different baseline characteristics to the risk of these events. The use of tamsulosin monotherapy (symptomatic treatment) has no impact on individual long‐term risk., Visual predictive checks. The line shows observed survival over time, whereas the shaded area describes the model predicted 95% CI for the survival. The different slopes of the survival curves for dutasteride monotherapy and combination therapy (relative to placebo) reflect the disease‐modifying properties of the intervention.
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- 2021
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32. Nuclear forensic signatures and structural analysis of uranyl oxalate, its products of thermal decomposition and Fe impurity dopant
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Nathan B.A. Thompson, Neil C. Hyatt, Martin C. Stennett, and Matthew R. Gilbert
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Nuclear fuel cycle ,Materials science ,Dopant ,Health, Toxicology and Mutagenesis ,Nuclear forensics ,Thermal decomposition ,Public Health, Environmental and Occupational Health ,02 engineering and technology ,Thermal treatment ,021001 nanoscience & nanotechnology ,010403 inorganic & nuclear chemistry ,Uranyl ,01 natural sciences ,Pollution ,Spent nuclear fuel ,Oxalate ,0104 chemical sciences ,Analytical Chemistry ,chemistry.chemical_compound ,Nuclear Energy and Engineering ,chemistry ,Chemical engineering ,Radiology, Nuclear Medicine and imaging ,0210 nano-technology ,Spectroscopy - Abstract
Uranyl oxalate (UO2C2O4·xH2O) may exist at the back-end of the nuclear fuel cycle (NFC) as an intermediate in spent fuel reprocessing. The conditions used in aqueous reprocessing and thermal treatment can affect the physical and chemical properties of the material. Furthermore, trace impurities, such as Fe, may incorporate into the structure of these materials. In nuclear forensics, understanding relationships between processing variables aids in determination of provenance and processing history. In this study, the thermal decomposition of UO2C2O4·3H2O and phase analysis of its thermal products are examined. Their morphologies are discussed with respect to a matrix of solution processing conditions.
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- 2021
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33. Synthesis, antiproliferative and antitrypanosomal activities, and DNA binding of novel 6-amidino-2-arylbenzothiazoles
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Marijana Radić Stojković, Valentina Rep, Martin C. Taylor, Petra Grbčić, Iva Zonjić, Sandra Kraljević Pavelić, Livio Racane, John M. Kelly, and Silvana Raić-Malić
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antiproliferative activity ,Stereochemistry ,benzothiazole ,amidine ,Trypanosoma brucei ,ctDNA binding ,Trypanosoma brucei brucei ,Amidines ,Antiprotozoal Agents ,Drug Evaluation, Preclinical ,Substituent ,Imidazoline receptor ,Antineoplastic Agents ,RM1-950 ,Amidine ,Structure-Activity Relationship ,chemistry.chemical_compound ,Drug Discovery ,Humans ,Moiety ,Benzothiazoles ,Imidazolines ,Cell Proliferation ,Pharmacology ,biology ,DNA ,General Medicine ,Triazoles ,Benzothiazole ,biology.organism_classification ,Intercalating Agents ,chemistry ,Nucleic Acid Conformation ,Therapeutics. Pharmacology ,Colorectal Neoplasms ,Linker ,Research Article ,Research Paper - Abstract
A series of 6-amidinobenzothiazoles, linked via phenoxymethylene or directly to the 1,2,3-triazole ring with a p-substituted phenyl or benzyl moiety, were synthesised and evaluated in vitro against four human tumour cell lines and the protozoan parasite Trypanosoma brucei. The influence of the type of amidino substituent and phenoxymethylene linker on antiproliferative and antitrypanosomal activities was observed, showing that the imidazoline moiety had a major impact on both activities. Benzothiazole imidazoline 14a, which was directly connected to N-1-phenyl-1,2,3-triazole, had the most potent growth-inhibitory effect (IC50 = 0.25 µM) on colorectal adenocarcinoma (SW620), while benzothiazole imidazoline 11b, containing a phenoxymethylene linker, exhibited the best antitrypanosomal potency (IC90 = 0.12 µM). DNA binding assays showed a non-covalent interaction of 6-amidinobenzothiazole ligands, indicating both minor groove binding and intercalation modes of DNA interaction. Our findings encourage further development of novel structurally related 6-amidino-2-arylbenzothiazoles to obtain more selective anticancer and anti-HAT agents., Graphical Abstract
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- 2021
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34. Novel TCNQ-stacking motifs in (12-crown-4)-complexes of alkali metal TCNQ salts
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Andrea E. Russell, Bingjia Yan, Peter N. Horton, Martin C. Grossel, and Simon C. Weston
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Crystallography ,Chemistry ,Stacking ,General Materials Science ,General Chemistry ,Condensed Matter Physics ,Alkali metal - Abstract
An investigation of the solid-state behaviour of five 12-crown-4 alkali metal TCNQ complexes, (12-crown-4)2LiTCNQ (1), (12-crown-4)2NaTCNQ (2), (12-crown-4)2Li(TCNQ)2 (3), (12-crown-4)2Na(TCNQ)2 (4), and (12-crown-4)2K(TCNQ)2 (5), reveals an unusual “cross-stitch” packing motif with the extended face-to-face π-stacked TCNQ˙− columns present in complexes 1 and 2. The effect of the presence of additional neutral TCNQ0 has also been explored.
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- 2021
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35. Safely probing the chemistry of Chernobyl nuclear fuel using micro-focus X-ray analysis
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Shi-Kuan Sun, Malin C. Dixon Wilkins, Daniel Grolimund, Hao Ding, Neil C. Hyatt, Martin C. Stennett, Clémence Gausse, Sarah Nicholas, Ryan Tappero, Claire L. Corkhill, and Lucy M. Mottram
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Chernobylite ,Nuclear fuel ,Renewable Energy, Sustainability and the Environment ,Metallurgy ,chemistry.chemical_element ,02 engineering and technology ,General Chemistry ,Nuclear reactor ,Uranium ,021001 nanoscience & nanotechnology ,010403 inorganic & nuclear chemistry ,01 natural sciences ,Nuclear decommissioning ,0104 chemical sciences ,law.invention ,Amorphous solid ,chemistry ,law ,Phase (matter) ,General Materials Science ,0210 nano-technology ,Solid solution - Abstract
Detailed chemical analysis of the solidified molten fuel still residing in the stricken Chernobyl reactor unit 4 are inferred using multi-modal micro-focus X-ray analysis of a low-radioactivity proxy. A fascinating mixture of molten UO2, nuclear fuel cladding, concrete, stainless steel and other nuclear reactor components, these materials behaved like lava, solidifying to form a complex, highly radioactive glass-ceramic. Using element-specific chemical probes (micro-X-ray fluorescence and X-ray absorption spectroscopy), coupled with micro-diffraction analysis, the crystalline phase assemblage of simulants of these heterogeneous materials was established, which included “chernobylite” and a range of compositions in the (U1−xZrx)O2 solid solution. Novel insight to nuclear accident fuel chemistry was obtained by establishing the oxidation state and local coordination of uranium not only in these crystalline phases, but uniquely in the amorphous fraction of the material, which varied depending on the history of the nuclear lava as it flowed through the reactor. This study demonstrates that micro-focus X-ray analysis of very small fractions of material can yield rich chemical information, which can be applied to nuclear-melt down materials to aid decommissioning and nuclear fuel management at nuclear accident sites.
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- 2021
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36. Impact of early vs. delayed initiation of dutasteride/tamsulosin combination therapy on the risk of acute urinary retention or BPH-related surgery in LUTS/BPH patients with moderate-to-severe symptoms at risk of disease progression
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Chandrashekhar Chavan, Oscar Della Pasqua, Matthias Oelke, Martin C. Michel, Claus G. Roehrborn, Michael J. Manyak, Salvatore D'Agate, and Juan Manuel Palacios-Moreno
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Tamsulosin ,Male ,medicine.medical_specialty ,Time Factors ,Combination therapy ,Urology ,Prostatic Hyperplasia ,030232 urology & nephrology ,Risk Assessment ,Severity of Illness Index ,03 medical and health sciences ,chemistry.chemical_compound ,5-alpha Reductase Inhibitors ,0302 clinical medicine ,Lower Urinary Tract Symptoms ,Lower urinary tract symptoms ,medicine ,Humans ,Cumulative incidence ,Survival analysis ,Benign prostatic hyperplasia ,Clinical trial simulations ,BPH-related surgery ,business.industry ,Urinary retention ,Dutasteride ,Urinary Retention ,medicine.disease ,Acute urinary retention ,Surgery ,Relative risk ,Drug Combinations ,chemistry ,030220 oncology & carcinogenesis ,Acute Disease ,Adrenergic alpha-1 Receptor Antagonists ,Disease Progression ,Original Article ,Symptom Assessment ,medicine.symptom ,business ,medicine.drug - Abstract
Purpose To evaluate the effect of delayed start of combination therapy (CT) with dutasteride 0.5 mg and tamsulosin 0.4 mg on the risk of acute urinary retention or benign prostatic hyperplasia (BPH)-related surgery (AUR/S) in patients with moderate-to-severe lower urinary tract symptoms (LUTS) at risk of disease progression. Methods Using a time-to-event model based on pooled data from 10,238 patients from Phase III/IV dutasteride trials, clinical trial simulations (CTS) were performed to assess the risk of AUR/S up to 48 months in moderate-to-severe LUTS/BPH patients following immediate and delayed start of CT for those not responding to tamsulosin monotherapy. Simulation scenarios (1300 subjects/arm) were investigated, including immediate start (reference) and alternative delayed start (six scenarios 1–24 months). AUR/S incidence was described by Kaplan–Meier survival curves and analysed using log-rank test. The cumulative incidence of events as well as the relative and attributable risks were summarised stratified by treatment. Results Survival curves for patients starting CT at month 1 and 3 did not differ from those who initiated CT immediately. By contrast, significant differences (p Conclusions Start of CT before month 6 appears to significantly reduce the risk of AUR/S compared with delayed start by ≥ 6 months. This has implications for the treatment algorithm for men with LUTS/BPH at risk of disease progression.
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- 2020
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37. Effect of Ti4+ on the structure of nepheline (NaAlSiO4) glass
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Emily T. Nienhuis, Charles Le Losq, José Marcial, Daniel R. Neuville, Thibaut Robine, John S. McCloy, Martin C. Stennett, Neil C. Hyatt, Washington State University (WSU), Pacific Northwest National Laboratory (PNNL), Institut de Physique du Globe de Paris (IPGP), Institut national des sciences de l'Univers (INSU - CNRS)-IPG PARIS-Université de La Réunion (UR)-Centre National de la Recherche Scientifique (CNRS)-Université de Paris (UP), and University of Sheffield [Sheffield]
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Materials science ,Coordination sphere ,010504 meteorology & atmospheric sciences ,Absorption spectroscopy ,Analytical chemistry ,Neutron scattering ,010502 geochemistry & geophysics ,01 natural sciences ,law.invention ,Glass structure ,chemistry.chemical_compound ,symbols.namesake ,Geochemistry and Petrology ,law ,Nepheline ,Crystallization ,0105 earth and related environmental sciences ,Titanium ,Extended X-ray absorption fine structure ,[CHIM.MATE]Chemical Sciences/Material chemistry ,X-ray scattering ,Silicate ,chemistry ,symbols ,Absorption (chemistry) ,Raman spectroscopy ,[SDU.STU.MI]Sciences of the Universe [physics]/Earth Sciences/Mineralogy - Abstract
International audience; In this study, the effect of Ti 4+ on the structure of nepheline glass (NaAlSiO 4) is investigated as SiO 2 is systematically replaced with TiO 2. Traditionally, TiO 2 is considered to be a nucleating agent for silicate crystallization but can also be incorporated into the glass network in relatively large amounts as either a network former or modifier depending on its coordination with oxygen. To determine the effect of Ti 4+ on the structure of nepheline glass, X-ray and neutron pair distribution function (PDF) analysis paired with Empirical Potential Structure Refinement (EPSR) were conducted and are supplemented with Raman spectroscopy, electron probe microanalysis, and X-ray absorption spectroscopy (including Extended X-ray Absorption Fine Structure, EXAFS). Through these methods, it has been found that up to 15 mol% (16 wt%) TiO 2 can incorporate into the glass network as a four-fold coordinated species, with a minor contribution of higher coordinated Ti. Between NaAlTi 0.1 Si 0.9 O 4 and NaAlTi 0.2 Si 0.8 O 4 , EXAFS suggests a local structure change in the second coordination sphere of Ti, which changes from Ti-Ti to Ti-Al. Raman spectroscopy also suggests that as Ti content increases, the Na environment becomes more ordered. These results suggest that the Ti activity coefficient and its isotopic fractionation for magnetite and other Ti-bearing minerals should be fairly constant in polymerized melts, such as metaluminous and peraluminous rhyolites.
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- 2020
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38. Molten salt synthesis of Ce doped zirconolite for the immobilisation of pyroprocessing wastes and separated plutonium
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Florent Tocino, Neil C. Hyatt, Amber R. Mason, and Martin C. Stennett
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010302 applied physics ,Zirconolite ,Materials science ,Process Chemistry and Technology ,Sintering ,chemistry.chemical_element ,02 engineering and technology ,Pyroprocessing ,021001 nanoscience & nanotechnology ,01 natural sciences ,Surfaces, Coatings and Films ,Electronic, Optical and Magnetic Materials ,Plutonium ,chemistry ,Chemical engineering ,Phase (matter) ,Reagent ,0103 physical sciences ,Materials Chemistry ,Ceramics and Composites ,Molten salt ,0210 nano-technology ,Perovskite (structure) - Abstract
Molten salt mediated synthesis of zirconolite Ca0.9Zr0.9Ce0.2Ti2O7 was investigated, as a target ceramic matrix for the clean-up of waste molten salts from pyroprocessing of spent nuclear fuels and the immobilisation of separated plutonium. A systematic study of reaction variables, including reaction temperature, time, atmosphere, reagents and composition, was made to optimise the yield of the target zirconolite phase. Zirconolite 2M and 3T polytypes were formed as the major phase (with minor perovskite) between 1000 – 1400 °C, in air, with the relative proportion of 2M polytype increasing with temperature. Synthesis under 5% H2/N2 or Ar increased the proportion of minor perovskite phase and reduced the yield of the zirconolite phase. The yield of zirconolite polytypes was maximised with the addition of 10 wt.% TiO2 and 5 wt.% TiO2, yielding 91.7 ± 2.0 wt.% zirconolite, primarily as the 2M polytype, after reaction at 1200 °C for 2 h, in air. The particle size and morphology of the zirconolite product bears a close resemblance to that of the TiO2 precursor, demonstrating a dominant template growth mechanism. Although the molten salt mediated synthesis of zirconolite is effective at lower reaction temperature and time, compared to reactive sintering, this investigation has demonstrated that the approach does not offer any clear advantage with over conventional reactive sintering for the envisaged application.
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- 2020
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39. The impact of three weeks of pre-quit varenicline on reinforcing value and craving for cigarettes in a laboratory choice procedure
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Schuyler C. Lawson, Martin C. Mahoney, Robert K. Cooper, Sarah S. Tonkin, Craig R. Colder, Stephen T. Tiffany, Larry W. Hawk, and Julie C. Gass
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Adult ,Male ,medicine.medical_specialty ,medicine.medical_treatment ,Craving ,Placebo ,Article ,law.invention ,03 medical and health sciences ,chemistry.chemical_compound ,0302 clinical medicine ,Double-Blind Method ,Randomized controlled trial ,law ,Quinoxalines ,medicine ,Humans ,Nicotinic Agonists ,Varenicline ,Retrospective Studies ,Pharmacology ,Cigarette craving ,Smokers ,business.industry ,Smoking ,Smoking cues ,Benzazepines ,Middle Aged ,030227 psychiatry ,Treatment Outcome ,chemistry ,behavior and behavior mechanisms ,Physical therapy ,Smoking cessation ,Female ,Smoking Cessation ,Active treatment ,Cues ,medicine.symptom ,Laboratories ,business ,Reinforcement, Psychology ,030217 neurology & neurosurgery - Abstract
RATIONALE: Varenicline, a partial nicotinic agonist, is theorized to attenuate pre-quit smoking reinforcement and post-quit withdrawal and craving. However, the mechanisms of action have not been fully characterized, as most studies employ only retrospective self-report measures, hypothetical indices of reinforcing value, and/or non-treatment seeking samples. OBJECTIVES: The current research examined the impact of pre-quit varenicline (vs. placebo) on laboratory measures of smoking and food (v. water) reinforcement and craving. METHODS: Participants were 162 treatment-seeking smokers enrolled in a randomized controlled trial of smoking cessation (clinicaltrials.gov ID: NCT03262662). Participants completed two laboratory sessions: a pre-treatment session, ~1 week prior to beginning varenicline or placebo, and an active treatment session, after ~3 weeks of treatment. At each session, participants completed a laboratory choice procedure; on each of 36 trials, a lit cigarette, food item, or cup of water was randomly presented. Participants reported level of craving and spent $0.01-$0.25 to have a corresponding 5%-95% chance to sample the cue. RESULTS: As predicted, spending was significantly higher on cigarette trials than water trials, and varenicline resulted in a greater between-session decline in spending on cigarette trials (but not water) than did placebo. Cigarette craving was enhanced in the presence of smoking cues compared to water, but neither average (tonic) cigarette craving nor cue-specific cigarette craving was significantly influenced by varenicline. Food spending and craving were generally unaffected by varenicline treatment. CONCLUSIONS: These laboratory data from treatment-seeking smokers provide the strongest evidence to date that varenicline selectively attenuates smoking reinforcement prior to quitting.
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- 2020
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40. The Effect of Temperature on the Stability and Cerium Oxidation State of CeTi2O6 in Inert and Oxidizing Atmospheres
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Martin C. Stennett, Malin C. Dixon Wilkins, Ewan R. Maddrell, and Neil C. Hyatt
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Inorganic Chemistry ,Inert ,Cerium ,chemistry ,Magazine ,law ,Oxidation state ,Oxidizing agent ,Inorganic chemistry ,chemistry.chemical_element ,Physical and Theoretical Chemistry ,law.invention - Abstract
Aliquots of well-characterized Ce-brannerite were annealed at different temperatures under N2 and synthetic air atmospheres. The autoreduction of cerium at temperature was observed using thermograv...
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- 2020
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41. Temporary Recovery of the Defect Responsible for Light- and Elevated Temperature-Induced Degradation: Insights Into the Physical Mechanisms Behind LeTID
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J. Schön, Wolfram Kwapil, Martin C. Schubert, Tim Niewelt, and Publica
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Silicon ,Hydrogen ,chemistry.chemical_element ,02 engineering and technology ,silicon solar cell ,01 natural sciences ,Temperature measurement ,Dissociation (chemistry) ,Monatomic ion ,0103 physical sciences ,transient simulation ,Electrical and Electronic Engineering ,010302 applied physics ,Dopant ,degradation models ,Chemistry ,Rate equation ,021001 nanoscience & nanotechnology ,Condensed Matter Physics ,Temperature induced ,Electronic, Optical and Magnetic Materials ,Silicium-Photovoltaik ,Chemical physics ,Photovoltaik ,0210 nano-technology ,Charakterisierung von Prozess- und Silicium-Materialien - Abstract
The effect of light- and elevated temperature-induced degradation (LeTID) can be nonpermanently reversed by charge carrier injection below the degradation temperature (commonly used degradation temperatures are above ~70 °C). In this study, we show that the rate of temporary recovery depends strongly on the excess carrier density. We observe that the order of the reaction changes from pseudo-zero to first with increasing injection. The rate decreases slightly with increasing temperature. Since the samples can go through multiple degradation/recovery cycles without distinct changes in the degradation kinetics, the experimentally accessible recovered and degraded states are interpreted as manifestations of the equilibrium concentrations of the defect responsible for LeTID at different temperatures. Based on our observations, we argue that the process underlying LeTID degradation is the dissociation of a precursor rather than an association of two or more components. In light of the relation between LeTID susceptibility and bulk hydrogen concentration, we hypothesize that the LeTID precursor dissociates into the LeTID defect and monatomic hydrogen. Numerical simulations of the coupled rate equations including hydrogen interactions well reproduce the experimental observations; according to these results, the presence of a sink for the atomic hydrogen such as dopant atoms is paramount for the LeTID degradation.
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- 2020
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42. Fatty Acid Oxidation Is an Adaptive Survival Pathway Induced in Prostate Tumors by HSP90 Inhibition
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Andrew J. Hoy, Chui Yan Mah, Zeyad D. Nassar, David J. Lynn, Swati Irani, Elizabeth V. Nguyen, Martin C. Sadowski, Max Moldovan, Julia S. Scott, Roger J. Daly, Margaret M. Centenera, Lisa M. Butler, and Shilpa R. Nagarajan
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Male ,0301 basic medicine ,Cancer Research ,Mass Spectrometry ,Hsp90 inhibitor ,03 medical and health sciences ,Prostate cancer ,chemistry.chemical_compound ,0302 clinical medicine ,medicine ,Humans ,HSP90 Heat-Shock Proteins ,Heat shock ,Molecular Biology ,Beta oxidation ,Fatty acid metabolism ,Chemistry ,Fatty Acids ,Prostatic Neoplasms ,Cancer ,medicine.disease ,Survival Analysis ,030104 developmental biology ,Oncology ,Apoptosis ,030220 oncology & carcinogenesis ,Perhexiline ,Cancer research ,Oxidation-Reduction ,medicine.drug - Abstract
HSP90 is a molecular chaperone required for stabilization and activation of hundreds of client proteins, including many known oncoproteins. AUY922 (luminespib), a new-generation HSP90 inhibitor, exhibits potent preclinical efficacy against several cancer types including prostate cancer. However, clinical use of HSP90 inhibitors for prostate cancer has been limited by toxicity and treatment resistance. Here, we aimed to design an effective combinatorial therapeutic regimen that utilizes subtoxic doses of AUY922, by identifying potential survival pathways induced by AUY922 in clinical prostate tumors. We conducted a proteomic analysis of 30 patient-derived explants (PDE) cultured in the absence and presence of AUY922, using quantitative mass spectrometry. AUY922 significantly increased the abundance of proteins involved in oxidative phosphorylation and fatty acid metabolism in the PDEs. Consistent with these findings, AUY922-treated prostate cancer cell lines exhibited increased mitochondrial mass and activated fatty acid metabolism processes. We hypothesized that activation of fatty acid oxidation is a potential adaptive response to AUY922 treatment and that cotargeting this process will sensitize prostate cancer cells to HSP90 inhibition. Combination treatment of AUY922 with a clinical inhibitor of fatty acid oxidation, perhexiline, synergistically decreased viability of several prostate cancer cell lines, and had significant efficacy in PDEs. The novel drug combination treatment induced cell-cycle arrest and apoptosis, and attenuated the heat shock response, a known mediator of HSP90 treatment resistance. This combination warrants further preclinical and clinical investigation as a novel strategy to overcome resistance to HSP90 inhibition. Implications: Metabolic pathways induced in tumor cells by therapeutic agents may be critical, but targetable, mediators of treatment resistance.
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- 2020
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43. Simple Mercury-Free Synthesis and Characterization of Symmetric and Unsymmetric Mono- and Dialkynyl (tpy)Au(III) Complexes
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Martin C. Dietl, Marte Sofie Martinsen Holmsen, A. Stephen K. Hashmi, Matthias Rudolph, Frank Rominger, Sigurd Øien-Ødegaard, Sina Witzel, and Mats Tilset
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Denticity ,010405 organic chemistry ,Organic Chemistry ,chemistry.chemical_element ,010402 general chemistry ,01 natural sciences ,Combinatorial chemistry ,0104 chemical sciences ,Mercury (element) ,Inorganic Chemistry ,chemistry.chemical_compound ,chemistry ,Reagent ,parasitic diseases ,Pyridine ,Physical and Theoretical Chemistry - Abstract
A highly efficient mercury-free route, providing [C^N] cyclometalated symmetric dialkynyl gold(III) complexes with 2-(p-tolyl)pyridine (tpy) as bidentate ligands and using alkynyllithium reagents, ...
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44. Auditory DUM neurons in a bush-cricket: inhibited inhibitors
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Andreas Stumpner, Silvia Gubert, Debbra Y. Knorr, and Martin C. Göpfert
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Male ,Auditory Pathways ,Neurite ,Physiology ,Population ,Biology ,Inhibitory postsynaptic potential ,GABA Antagonists ,Gryllidae ,03 medical and health sciences ,Behavioral Neuroscience ,chemistry.chemical_compound ,0302 clinical medicine ,Hearing ,Postsynaptic potential ,medicine ,Animals ,Picrotoxin ,Graded potential ,education ,gamma-Aminobutyric Acid ,Ecology, Evolution, Behavior and Systematics ,Inhibition ,030304 developmental biology ,Neurons ,Original Paper ,0303 health sciences ,education.field_of_study ,Excitatory Postsynaptic Potentials ,Segmental interneurone ,Immunohistochemistry ,Ganglia, Invertebrate ,medicine.anatomical_structure ,Acoustic Stimulation ,Inhibitory Postsynaptic Potentials ,nervous system ,chemistry ,Auditory Perception ,Excitatory postsynaptic potential ,Female ,Animal Science and Zoology ,Soma ,Insect ,Neuroscience ,030217 neurology & neurosurgery - Abstract
Thoracic ganglia of many hearing insects house the first level of auditory processing. In bush-crickets, the largest population of local auditory neurons in the prothoracic processing centre are dorsal unpaired median (DUM) neurons. It has been suggested that DUM neurons are inhibitory using γ-aminobutyric acid (GABA) as transmitter. Immunohistochemistry reveals a population of about 35–50 GABA-positive somata in the posterior medial cluster of the prothoracic ganglion. Only very few small somata in this cluster remain unstained. At least 10 neurites from 10 neurons can be identified. Intracellularly stained auditory DUM neurons have their soma in the cluster of median GABA positive cells and most of them exhibit GABA-immunoreactivity. Responses of certain DUM neurons show obvious signs of inhibition. Application of picrotoxin (PTX), a chloride-channel blocker in insects, changes the responses of many DUM neurons. They become broader in frequency tuning and broader or narrower in temporal pattern tuning. Furthermore, inhibitory postsynaptic potentials (IPSPs) may be replaced by excitatory postsynaptic potentials. Loss of an IPSP in the rising graded potential after PTX-application leads to a significant reduction of first-spike latency. Therefore, auditory DUM neurons receive effective inhibition and are the best candidates for inhibition in DUM neurons and other auditory interneurons. Electronic supplementary material The online version of this article (10.1007/s00359-020-01438-2) contains supplementary material, which is available to authorized users.
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45. A pipeline for complete characterization of complex germline rearrangements from long DNA reads
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Satomi Mitsuhashi, Sachiko Ohori, Naomichi Matsumoto, Martin C. Frith, and Kazutaka Katoh
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lcsh:QH426-470 ,lcsh:Medicine ,Computational biology ,Biology ,Translocation, Genetic ,Germline ,Structural variation ,Chromosome Breakpoints ,chemistry.chemical_compound ,Genetics ,Humans ,Genetic Predisposition to Disease ,Molecular Biology ,Genetic Association Studies ,Germ-Line Mutation ,Genetics (clinical) ,Long read sequencing ,Chromosome Aberrations ,Gene Rearrangement ,Chromothripsis ,Whole Genome Sequencing ,Genome, Human ,Research ,Breakpoint ,lcsh:R ,High-Throughput Nucleotide Sequencing ,Chromosomal translocations/rearrangements ,Genomics ,Human genetics ,lcsh:Genetics ,chemistry ,Molecular Medicine ,Human genome ,Nanopore sequencing ,DNA ,Genome-Wide Association Study - Abstract
Background Many genetic/genomic disorders are caused by genomic rearrangements. Standard methods can often characterize these variations only partly, e.g., copy number changes or breakpoints. It is important to fully understand the order and orientation of rearranged fragments, with precise breakpoints, to know the pathogenicity of the rearrangements. Methods We performed whole-genome-coverage nanopore sequencing of long DNA reads from four patients with chromosomal translocations. We identified rearrangements relative to a reference human genome, subtracted rearrangements shared by any of 33 control individuals, and determined the order and orientation of rearranged fragments, with our newly developed analysis pipeline. Results We describe the full characterization of complex chromosomal rearrangements, by filtering out genomic rearrangements seen in controls without the same disease, reducing the number of loci per patient from a few thousand to a few dozen. Breakpoint detection was very accurate; we usually see ~ 0 ± 1 base difference from Sanger sequencing-confirmed breakpoints. For one patient with two reciprocal chromosomal translocations, we find that the translocation points have complex rearrangements of multiple DNA fragments involving 5 chromosomes, which we could order and orient by an automatic algorithm, thereby fully reconstructing the rearrangement. A rearrangement is more than the sum of its parts: some properties, such as sequence loss, can be inferred only after reconstructing the whole rearrangement. In this patient, the rearrangements were evidently caused by shattering of the chromosomes into multiple fragments, which rejoined in a different order and orientation with loss of some fragments. Conclusions We developed an effective analytic pipeline to find chromosomal aberration in congenital diseases by filtering benign changes, only from long read sequencing. Our algorithm for reconstruction of complex rearrangements is useful to interpret rearrangements with many breakpoints, e.g., chromothripsis. Our approach promises to fully characterize many congenital germline rearrangements, provided they do not involve poorly understood loci such as centromeric repeats.
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- 2020
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46. Determination of glyphosate, AMPA and glufosinate by high performance liquid chromatography with fluorescence detection in waters of the Santarém Plateau, Brazilian Amazon
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Denise Carvalho Mello, Eloisa Dutra Caldas, Carlos Martin C. Infante, Nayara Luiz Pires, Moema G. A. Morgado, and Carlos José Sousa Passos
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Glycine ,010501 environmental sciences ,01 natural sciences ,High-performance liquid chromatography ,Fluorescence ,chemistry.chemical_compound ,Limit of Detection ,alpha-Amino-3-hydroxy-5-methyl-4-isoxazolepropionic Acid ,Chromatography, High Pressure Liquid ,0105 earth and related environmental sciences ,geography ,Plateau ,geography.geographical_feature_category ,Herbicides ,Amazon rainforest ,Aminobutyrates ,010401 analytical chemistry ,Reproducibility of Results ,Water ,General Medicine ,Pollution ,0104 chemical sciences ,Freeze Drying ,chemistry ,Glufosinate ,Environmental chemistry ,Glyphosate ,Environmental science ,Brazil ,Water Pollutants, Chemical ,Environmental Monitoring ,Food Science - Abstract
Herbicide use, mainly glyphosate, has been intense in worldwide agriculture, including in the Brazilian Amazon region. This study aimed to validate a method for determining glyphosate and its degradation product, AMPA, and glufosinate by HPLC-FL in 58 water samples collected at the Santarém plateau region (
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- 2020
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47. Circadian Potency Spectrum with Extended Exposure to Polychromatic White LED Light under Workplace Conditions
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Martin C. Moore-Ede, Rainer Guttkuhn, and Anneke Heitmann
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Melanopsin ,Adult ,Male ,Adolescent ,Light ,Physiology ,melatonin ,Retina ,Melatonin ,Young Adult ,Physiology (medical) ,medicine ,Potency ,light spectrum ,Humans ,Circadian rhythm ,human ,Workplace ,Lighting ,spectral sensitivity ,Chemistry ,Intrinsically photosensitive retinal ganglion cells ,Original Articles ,Circadian Rhythm ,White (mutation) ,Spectral sensitivity ,medicine.anatomical_structure ,circadian ,Biophysics ,Female ,medicine.drug - Abstract
Electric light has enabled humans to conquer the night, but light exposure at night can disrupt the circadian timing system and is associated with a diverse range of health disorders. To provide adequate lighting for visual tasks without disrupting the human circadian timing system, a precise definition of circadian spectral sensitivity is required. Prior attempts to define the circadian spectral sensitivity curve have used short (≤90-min) monochromatic light exposures in dark-adapted human subjects or in vitro dark-adapted isolated retina or melanopsin. Several lines of evidence suggest that these dark-adapted circadian spectral sensitivity curves, in addition to 430- to 499-nm (blue) wavelength sensitivity, may include transient 400- to 429-nm (violet) and 500- to 560-nm (green) components mediated by cone- and rod-originated extrinsic inputs to intrinsically photosensitive retinal ganglion cells (ipRGCs), which decay over the first 2 h of extended light exposure. To test the hypothesis that the human circadian spectral sensitivity in light-adapted conditions may have a narrower, predominantly blue, sensitivity, we used 12-h continuous exposures of light-adapted healthy human subjects to 6 polychromatic white light-emitting diode (LED) light sources with diverse spectral power distributions at recommended workplace levels of illumination (540 lux) to determine their effect on the area under curve of the overnight (2000–0800 h) salivary melatonin. We derived a narrow steady-state human Circadian Potency spectral sensitivity curve with a peak at 477 nm and a full-width half-maximum of 438 to 493 nm. This light-adapted Circadian Potency spectral sensitivity permits the development of spectrally engineered LED light sources to minimize circadian disruption and address the health risks of light exposure at night in our 24/7 society, by alternating between daytime circadian stimulatory white light spectra and nocturnal circadian protective white light spectra.
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- 2020
48. Mutually stabilizing interactions between proto-peptides and RNA
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Jay W. Haynes, Loren Dean Williams, Ahmad M. Mohyeldin, Nicholas V. Hud, Moran Frenkel-Pinter, Luke J. Leman, Alyssa B. Sargon, Ramanarayanan Krishnamurthy, Anton S. Petrov, and Martin C
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Ornithine ,Protein Folding ,RNA Stability ,Stereochemistry ,Science ,Origin of Life ,General Physics and Astronomy ,010402 general chemistry ,01 natural sciences ,Article ,General Biochemistry, Genetics and Molecular Biology ,Evolution, Molecular ,Cations ,Amino Acid Sequence ,lcsh:Science ,Nuclear Magnetic Resonance, Biomolecular ,Peptide sequence ,Depsipeptide ,chemistry.chemical_classification ,Multidisciplinary ,Protein Stability ,010405 organic chemistry ,Aminobutyrates ,Circular Dichroism ,Hydrolysis ,Cationic polymerization ,RNA ,General Chemistry ,0104 chemical sciences ,Amino acid ,chemistry ,beta-Alanine ,Nucleic acid ,Protein folding ,lcsh:Q ,Peptides ,Coevolution - Abstract
The close synergy between peptides and nucleic acids in current biology is suggestive of a functional co-evolution between the two polymers. Here we show that cationic proto-peptides (depsipeptides and polyesters), either produced as mixtures from plausibly prebiotic dry-down reactions or synthetically prepared in pure form, can engage in direct interactions with RNA resulting in mutual stabilization. Cationic proto-peptides significantly increase the thermal stability of folded RNA structures. In turn, RNA increases the lifetime of a depsipeptide by >30-fold. Proto-peptides containing the proteinaceous amino acids Lys, Arg, or His adjacent to backbone ester bonds generally promote RNA duplex thermal stability to a greater magnitude than do analogous sequences containing non-proteinaceous residues. Our findings support a model in which tightly-intertwined biological dependencies of RNA and protein reflect a long co-evolutionary history that began with rudimentary, mutually-stabilizing interactions at early stages of polypeptide and nucleic acid co-existence., Cooperative relationships are widespread among different classes of biopolymers and are predicted to have existed during emergence of life. This study shows that proto-peptides engage in mutually stabilizing interactions with RNA, providing support for the co-evolution of these molecules.
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- 2020
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49. Therapy-induced lipid uptake and remodeling underpin ferroptosis hypersensitivity in prostate cancer
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Berwyck L. J. Poad, Ali Talebi, Melanie Lehman, Kaylyn D. Tousignant, Johan Swinnen, Tuo Zang, Martin C. Sadowski, Rajesh Gupta, Chenwei Wang, Colleen C. Nelson, Stephen J. Blanksby, Atefeh Taherian Fard, Reuben S. E. Young, and Anja Rockstroh
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CASTRATION ,CELL-SURVIVAL ,Multidrug tolerance ,Membrane lipids ,STEROIDOGENESIS ,PROGRESSION ,GPX4 ,lcsh:RC254-282 ,DESATURATION ,Lipid peroxidation ,chemistry.chemical_compound ,Lipidomics ,Lipid remodeling ,Membrane fluidity ,Enzalutamide ,Ferroptosis ,ANDROGEN-DEPRIVATION ,Science & Technology ,Prostate cancer ,RECEPTOR ,MOLECULAR-MECHANISMS ,Research ,Therapy resistance ,Metabolic reprograming ,Lipid metabolism ,Lipid uptake ,Cell Biology ,CHOLESTEROL TRAFFICKING ,lcsh:Neoplasms. Tumors. Oncology. Including cancer and carcinogens ,Psychiatry and Mental health ,Oncology ,chemistry ,Cancer cell ,Cancer research ,Life Sciences & Biomedicine ,RESISTANCE - Abstract
BackgroundMetabolic reprograming, non-mutational epigenetic changes, increased cell plasticity and multidrug tolerance are early hallmarks of therapy resistance in cancer. In this temporary, therapy-tolerant state, cancer cells are highly sensitive to ferroptosis, a form of regulated cell death that is caused by oxidative stress through excess levels of iron-dependent peroxidation of polyunsaturated fatty acids (PUFA). However, mechanisms underpinning therapy-induced ferroptosis hypersensitivity remain to be elucidated.MethodsWe used quantitative single cell imaging of fluorescent metabolic probes, transcriptomics, proteomics and lipidomics to perform a longitudinal analysis of the adaptive response to androgen receptor-targeted therapies (androgen deprivation and enzalutamide) in prostate cancer (PCa).ResultsWe discovered that cessation of cell proliferation and a robust reduction in bioenergetic processes were associated with multidrug tolerance and a strong accumulation of lipids. The gain in lipid biomass was fueled by enhanced lipid uptake through cargo non-selective (macropinocytosis, tunneling nanotubes) and cargo-selective mechanisms (lipid transporters), whereasde novolipid synthesis was strongly reduced. Enzalutamide induced extensive lipid remodeling of all major phospholipid classes at the expense of storage lipids, leading to increased desaturation and acyl chain length of membrane lipids. The rise in membrane PUFA levels enhanced membrane fluidity and lipid peroxidation, causing hypersensitivity to glutathione peroxidase (GPX4) inhibition and ferroptosis. Combination treatments against AR and fatty acid desaturation, lipase activities or growth medium supplementation with antioxidants or PUFAs altered GPX4 dependence. Despite multidrug tolerance, PCa cells displayed an enhanced sensitivity to inhibition of lysosomal processing of exogenous lipids, highlighting an increased dependence on lipid uptake in the therapy-tolerant state.ConclusionsOur work provides mechanistic insight into processes of lipid metabolism that underpin the acquisition of therapy-induced GPX4 dependence and ferroptosis hypersensitivity to standard of care therapies in PCa. It demonstrated novel strategies to suppress the therapy-tolerant state that may have potential to delay and combat resistance to androgen receptor-targeted therapies, a currently unmet clinical challenge of advanced PCa. Since enhanced GPX4 dependence is an adaptive phenotype shared by several types of cancer in response to different therapies, our work might have universal implications for our understanding of metabolic events that underpin resistance to cancer therapies.
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- 2020
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50. Human lung extracellular matrix hydrogels resemble the stiffness and viscoelasticity of native lung tissue
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Martin C. Harmsen, Machteld N. Hylkema, M Roobeek, Prashant K. Sharma, Janette K. Burgess, R.H.J. de Hilster, Wim Timens, Eric S. White, Marnix R. Jonker, E A Gercama, Guided Treatment in Optimal Selected Cancer Patients (GUTS), Groningen Research Institute for Asthma and COPD (GRIAC), Restoring Organ Function by Means of Regenerative Medicine (REGENERATE), and Reproductive Origins of Adult Health and Disease (ROAHD)
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0301 basic medicine ,Pulmonary and Respiratory Medicine ,Swine ,Physiology ,extracellular matrix ,02 engineering and technology ,macromolecular substances ,complex mixtures ,Viscoelasticity ,Extracellular matrix ,Pulmonary Disease, Chronic Obstructive ,03 medical and health sciences ,Idiopathic pulmonary fibrosis ,Vascular Stiffness ,Physiology (medical) ,medicine ,Animals ,Humans ,COPD ,Lung ,Decellularization ,Rapid Report ,Viscosity ,Chemistry ,Generalized Maxwell model ,technology, industry, and agriculture ,Hydrogels ,Cell Biology ,021001 nanoscience & nanotechnology ,medicine.disease ,Idiopathic Pulmonary Fibrosis ,Pepsin A ,Obstructive lung disease ,respiratory tract diseases ,030104 developmental biology ,medicine.anatomical_structure ,IPF ,Self-healing hydrogels ,Biophysics ,rheology ,hydrogel ,0210 nano-technology - Abstract
Chronic lung diseases such as idiopathic pulmonary fibrosis (IPF) and chronic obstructive pulmonary disease (COPD) are associated with changes in extracellular matrix (ECM) composition and abundance affecting the mechanical properties of the lung. This study aimed to generate ECM hydrogels from control, severe COPD [Global Initiative for Chronic Obstructive Lung Disease (GOLD) IV], and fibrotic human lung tissue and evaluate whether their stiffness and viscoelastic properties were reflective of native tissue. For hydrogel generation, control, COPD GOLD IV, and fibrotic human lung tissues were decellularized, lyophilized, ground into powder, porcine pepsin solubilized, buffered with PBS, and gelled at 37°C. Rheological properties from tissues and hydrogels were assessed with a low-load compression tester measuring the stiffness and viscoelastic properties in terms of a generalized Maxwell model representing phases of viscoelastic relaxation. The ECM hydrogels had a greater stress relaxation than tissues. ECM hydrogels required three Maxwell elements with slightly faster relaxation times (τ) than that of native tissue, which required four elements. The relative importance (Ri) of the first Maxwell element contributed the most in ECM hydrogels, whereas for tissue the contribution was spread over all four elements. IPF tissue had a longer-lasting fourth element with a higher Ri than the other tissues, and IPF ECM hydrogels did require a fourth Maxwell element, in contrast to all other ECM hydrogels. This study shows that hydrogels composed of native human lung ECM can be generated. Stiffness of ECM hydrogels resembled that of whole tissue, while viscoelasticity differed.
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- 2020
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