268 results on '"Owen JS"'
Search Results
2. Inhibition of atherosclerosis in apolipoprotein-E-deficient mice following muscle transduction with adeno-associated virus vectors encoding human apolipoprotein-E
- Author
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Harris, JD, Schepelmann, S, Athanasopoulos, T, Graham, IR, Stannard, AK, Mohri, Z, Hill, V, Hassall, DG, Owen, JS, and Dickson, G
- Published
- 2002
- Full Text
- View/download PDF
3. Efficient coexpression and secretion of anti-atherogenic human apolipoprotein AI and lecithin-cholesterol acyltransferase by cultured muscle cells using adeno-associated virus plasmid vectors
- Author
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Fan, L, Drew, J, Dunckley, MG, Owen, JS, and Dickson, G
- Published
- 1998
- Full Text
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4. Targeted intracellular voltage recordings from dendritic spines using quantum-dot-coated nanopipettes
- Author
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Jayant, K, Hirtz, JJ, Plante, IJL, Tsai, DM, De Boer, WDAM, Semonche, A, Peterka, DS, Owen, JS, Sahin, O, Shepard, KL, Yuste, R, Jayant, K, Hirtz, JJ, Plante, IJL, Tsai, DM, De Boer, WDAM, Semonche, A, Peterka, DS, Owen, JS, Sahin, O, Shepard, KL, and Yuste, R
- Abstract
Dendritic spines are the primary site of excitatory synaptic input onto neurons, and are biochemically isolated from the parent dendritic shaft by their thin neck. However, due to the lack of direct electrical recordings from spines, the influence that the neck resistance has on synaptic transmission, and the extent to which spines compartmentalize voltage, specifically excitatory postsynaptic potentials, albeit critical, remains controversial. Here, we use quantum-dot-coated nanopipette electrodes (tip diameters ~15-30 nm) to establish the first intracellular recordings from targeted spine heads under two-photon visualization. Using simultaneous somato-spine electrical recordings, we find that back propagating action potentials fully invade spines, that excitatory postsynaptic potentials are large in the spine head (mean 26 mV) but are strongly attenuated at the soma (0.5-1 mV) and that the estimated neck resistance (mean 420 M & Omega;) is large enough to generate significant voltage compartmentalization. Nanopipettes can thus be used to electrically probe biological nanostructures.
- Published
- 2017
5. Deficiency of lecithin: cholesterol acyltransferase due to compound heterozygosity of two novel mutations (Gly33Arg and 30 bp ins) in the LCAT gene
- Author
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Gerd Assmann, Harald Funke, H. Wiebusch, Paul Cullen, Sharp Ps, Owen Js, and Collins D
- Subjects
Heterozygote ,medicine.medical_specialty ,Adolescent ,Molecular Sequence Data ,Glycine ,Arginine ,Compound heterozygosity ,medicine.disease_cause ,Phosphatidylcholine-Sterol O-Acyltransferase ,Lecithin Cholesterol Acyltransferase Deficiency ,Internal medicine ,Genetics ,medicine ,Humans ,Amino Acid Sequence ,Molecular Biology ,Gene ,Genetics (clinical) ,Aged ,chemistry.chemical_classification ,Mutation ,Base Sequence ,biology ,Heterozygote advantage ,General Medicine ,Middle Aged ,Mutagenesis, Insertional ,Enzyme ,Endocrinology ,Oligodeoxyribonucleotides ,chemistry ,Lecithin—cholesterol acyltransferase ,biology.protein ,Female ,Phosphatidylcholine—sterol O-acyltransferase - Published
- 1995
6. Electromagnetic induction of insensibility in animals: a review
- Author
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Small, A, primary, McLean, D, additional, Owen, JS, additional, and Ralph, J, additional
- Published
- 2013
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7. Preliminary investigations into the use of microwave energy for reversible stunning of sheep
- Author
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Small, A, primary, McLean, D, additional, Keates, H, additional, Owen, JS, additional, and Ralph, J, additional
- Published
- 2013
- Full Text
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8. Defective APO A1-Mediated Cholesterol Efflux from Dermal Fibroblasts in a Patient with Absent HDL-Cholesterol
- Author
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Baynes, KCR, primary, Schepelmann, S, additional, Johnstone, SR, additional, Soutar, AK, additional, Owen, JS, additional, Davies, S, additional, and Feher, MD, additional
- Published
- 2001
- Full Text
- View/download PDF
9. Regulation of the cholesterol efflux gene, ABCA1
- Author
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Wade, DP, primary and Owen, JS, additional
- Published
- 2001
- Full Text
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10. Transgenic mice expressing human apolipoprotein A-I have sera with modest trypanolytic activity in vitro but remain susceptible to infection by Trypanosoma brucei brucei.
- Author
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Owen, JS, primary, Gillett, MP, additional, and Hughes, TE, additional
- Published
- 1992
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11. Increased Na(+)-dependent D-glucose transport and altered lipid composition in renal cortical brush-border membrane vesicles from bile duct-ligated rats.
- Author
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Imai, Y, primary, Scoble, JE, additional, McIntyre, N, additional, and Owen, JS, additional
- Published
- 1992
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12. Comparison of the cytolytic effects in vitro on Trypanosoma brucei brucei of plasma, high density lipoproteins, and apolipoprotein A-I from hosts both susceptible (cattle and sheep) and resistant (human and baboon) to infection.
- Author
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Gillett, MP, primary and Owen, JS, additional
- Published
- 1992
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13. Relationships between the T-peak to T-end interval, ventricular tachyarrhythmia, and death in left ventricular systolic dysfunction.
- Author
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Morin DP, Saad MN, Shams OF, Owen JS, Xue JQ, Abi-Samra FM, Khatib S, Nelson-Twakor OS, and Milani RV
- Published
- 2012
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14. Role of platelet-activating factor in pneumolysin-induced acute lung injury.
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Witzenrath M, Gutbier B, Owen JS, Schmeck B, Mitchell TJ, Mayer K, Thomas MJ, Ishii S, Rosseau S, Suttorp N, and Schütte H
- Published
- 2007
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15. Apo E rich high density lipoproteins (HDL) in plasma of cirrhotic patients suppress lymphocyte proliferation
- Author
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Horton, RC, primary and Owen, JS, additional
- Published
- 1990
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16. S-adenosylmethionine (SAMe) reduces cholesterol deposition in erythrocyte membranes of cirrhotic patients
- Author
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Rafique, S, primary, Guardascione, M, additional, Burroughs, AK, additional, and Owen, JS, additional
- Published
- 1990
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17. Platelet Cholesterol Content and Platelet Aggregation
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Neil McIntyre, Hutton Ra, and Owen Js
- Subjects
medicine.medical_specialty ,Platelet aggregation ,Cholesterol ,business.industry ,Prostacyclin ,General Medicine ,chemistry.chemical_compound ,Endocrinology ,chemistry ,Internal medicine ,medicine ,Platelet ,Serum triglycerides ,business ,Inverse correlation ,medicine.drug - Published
- 1980
18. Neuroacanthocytosis. A clinical, haematological and pathological study of 19 cases
- Author
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Hardie, RJ, Pullon, HW, Harding, AE, Owen, JS, Pires, M, Daniels, GL, Imai, Y, Misra, VP, King, RH, and Jacobs, JM
- Published
- 1991
19. Metal Fluorides Passivate II-VI and III-V Quantum Dots.
- Author
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Valleix R, Zhang W, Jordan AJ, Guillemeney L, Castro LG, Zekarias BL, Park SV, Wang O, and Owen JS
- Abstract
Quantum dots (QDs) with metal fluoride surface ligands were prepared via reaction with anhydrous oleylammonium fluoride. Carboxylate terminated II-VI QDs underwent carboxylate for fluoride exchange, while InP QDs underwent photochemical acidolysis yielding oleylamine, PH
3 , and InF3 . The final photoluminescence quantum yield (PLQY) reached 83% for InP and near unity for core-shell QDs. Core-only CdS QDs showed dramatic improvements in PLQY, but only after exposure to air. Following etching, the InP QDs were bound by oleylamine ligands that were characterized by the frequency and breadth of the corresponding ν(N-H) bands in the infrared absorption spectrum. The fluoride content (1.6-9.2 nm-2 ) was measured by titration with chlorotrimethylsilane and compared with the oleylamine content (2.3-5.1 nm-2 ) supporting the formation of densely covered surfaces. The influence of metal fluoride adsorption on the air stability of QDs is discussed.- Published
- 2024
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20. A Physiologically Based Pharmacokinetic Modeling Approach to Assess the Potential for Drug Interactions Between Trofinetide and CYP3A4-Metabolized Drugs.
- Author
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Darwish M, Youakim JM, Darling I, Lukacova V, Owen JS, and Bradley H
- Subjects
- Humans, Pharmaceutical Preparations, Drug Interactions, Models, Biological, Cytochrome P-450 CYP3A Inhibitors, Cytochrome P-450 CYP3A metabolism, Midazolam pharmacokinetics, Glutamates
- Abstract
Purpose: Trofinetide is the first drug to be approved by the US Food and Drug Administration for use in the treatment of patients with Rett syndrome, a multisystem disorder requiring multimodal therapies. Cytochrome P450 (CYP) 3A4 metabolizes >50% of therapeutic drugs and is the CYP isozyme most commonly expressed in the liver and intestines. In vitro studies suggest the concentration of trofinetide producing 50% inhibition (IC
50 ) of CYP3A4 is >15 mmol/L; that concentration was much greater than the target clinical concentration associated with the maximal intended therapeutic dose (12 g). Thus, trofinetide has a low potential for drug-drug interactions in the liver. However, there is potential for drug-drug interactions in the intestines given the oral route of administration and expected relatively high concentration in the gastrointestinal tract after dose administration., Methods: Using a validated physiologically based pharmacokinetic (PBPK) model, deterministic and stochastic simulations were used for assessing the PK properties related to exposure and bioavailability of midazolam (sensitive index substrate for CYP3A4) following an oral (15 mg) or intravenous (2 mg) dose, with and without single-dose and steady-state (12 g) coadministration of oral trofinetide., Findings: Following coadministration of intravenous midazolam and oral trofinetide, the PK properties of midazolam were unchanged. The trofinetide concentration in the gut wall was >15 mmol/L during the first 1.5 hours after dosing. With the coadministration of oral midazolam and trofinetide, the model predicted increases in fraction of dose reaching the portal vein, bioavailability, Cmax , and AUCinf of 30%, 30%, 18%, and 30%, respectively., Implications: In this study that used a PBPK modeling approach, it was shown that CYP3A4 enzyme activity in the liver was not affected by trofinetide coadministration, but trofinetide was predicted to be a weak inhibitor of intestinal CYP3A4 metabolism after oral administration at therapeutic doses., Competing Interests: Declaration of competing interest M.D., J.M.Y., and H.B. are employees of Acadia Pharmaceuticals Inc. V.L. and I.D. are employees of, and hold stock options in, Simulations Plus. J.S.O. is a former employee of Simulations Plus. The authors have indicated that they have no other conflicts of interest with regard to the content of this article., (Copyright © 2024 The Authors. Published by Elsevier Inc. All rights reserved.)- Published
- 2024
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21. Investigating the Benefits of Tectonite Dust as an Amendment for Bark Substrates and Dryland Crops.
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Nackley L, Van Lehman L, Van Lehman O, Owen JS Jr, and Scagel C
- Abstract
This study investigates the potential benefits of using tectonite dust as a soil amendment in central Oregon. Tectonite, a rare mineral byproduct of the Warm Springs Composite Products Company, has unique properties that can enhance soil fertility and water-holding capacity. The study includes analyses of tectonite's physical and chemical properties, small-scale growth trials, and farm-scale experiments to measure grain yield. Physical property analysis demonstrated that tectonite increased water-holding capacity and improved soil structure when added to bark substrates. Responses varied in mineral soils, affecting air space, and water-holding capacity. Small-scale trials showed positive growth responses in wheat height and biomass, indicating improved early growth and establishment. Farm-scale experiments confirmed increased grain yields with tectonite application. These findings suggest that tectonite enhances soil health and crop yields by improving structure, nutrient availability, and water retention. Careful sourcing and testing are necessary to address potential heavy metal contamination risks. Using tectonite as a soil amendment aligns with sustainability goals, reducing waste, and greenhouse gas emissions. It may also offer cost savings compared to synthetic fertilizers and stimulate the local economy. Further research is needed to understand the long-term effects of tectonite on edible crops and heavy metal content. Nevertheless, tectonite shows promise as a sustainable soil amendment for promoting agriculture in central Oregon. By exploring its potential benefits, farmers can enhance soil fertility, improve water-use efficiency, and contribute to a more sustainable agricultural system. This study highlights the importance of utilizing waste byproducts in agriculture to achieve environmental and economic sustainability. Tectonite has the potential to play a significant role in addressing water scarcity and enhancing crop productivity in arid regions like central Oregon.
- Published
- 2024
- Full Text
- View/download PDF
22. Population Pharmacokinetics of MYL-1402O, a Proposed Biosimilar to Bevacizumab and Reference Product (Avastin ® ) in Patients with Non-squamous Non-small Cell Lung Cancer.
- Author
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Owen JS, Rackley RJ, Hummel MA, Roepcke S, Huang H, Liu M, Idris TA, Murugesan SMN, Marwah A, Loganathan S, Ranganna G, Barve A, Waller CF, and Socinski MA
- Subjects
- Humans, Bevacizumab pharmacokinetics, Therapeutic Equivalency, Double-Blind Method, Carcinoma, Non-Small-Cell Lung drug therapy, Biosimilar Pharmaceuticals pharmacokinetics, Lung Neoplasms drug therapy
- Abstract
Background and Objectives: MYL-1402O is a bevacizumab (Avastin
® ) biosimilar. Pharmacokinetic and safety similarity of MYL-1402O and reference Avastin® authorized in the European Union (EU-Avastin® ) and the US (US-Avastin® ) was demonstrated in healthy subjects (phase I, NCT02469987). The key objectives of this study were to establish a population pharmacokinetic (PopPK) model on pooled data from the phase I and phase III clinical studies to assess pharmacokinetic linearity of MYL-1402O and Avastin® across dose ranges, to assess the pharmacokinetic similarity of MYL-1402O and Avastin® in patients with non-squamous non-small cell lung cancer (nsNSCLC), and to explore potential covariates to account for systematic sources of variability in bevacizumab exposure., Methods: Efficacy and safety of MYL-1402O compared with EU-Avastin® was investigated in a multicenter, double-blind, randomized, parallel-group study in patients with stage IV nsNSCLC (phase III, NCT04633564). PopPK models were developed using a nonlinear mixed effects approach (NONMEM® 7.3.0)., Results: The pharmacokinetics of Avastin® and MYL-1402O were adequately described with a two-compartment linear model. Fourteen covariates were found to be statistically significant predictors of bevacizumab pharmacokinectics. The impact of each covariate on area under the concentration-time curve, half-life, and maximum plasma concentration was modest, and ranges were similar between the treatment groups, MYL-1402O and EU-Avastin® , in patients with nsNSCLC. The pharmacokinectics of bevacizumab appeared to be linear., Conclusions: PopPK analysis revealed no significant differences between pharmacokinetics of MYL-1402O and Avastin® in patients with nsNSCLC. The developed PopPK model was considered robust, as it adequately described bevacizumab pharmacokinetics in healthy participants and nsNSCLC patients., (© 2023. The Author(s), under exclusive licence to Springer Nature Switzerland AG.)- Published
- 2023
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23. Synthesis of graded CdS 1- x Se x nanoplatelet alloys and heterostructures from pairs of chalcogenoureas with tailored conversion reactivity.
- Author
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Saenz N, Hamachi LS, Wolock A, Goodge BH, Kuntzmann A, Dubertret B, Billinge I, Kourkoutis LF, Muller DA, Crowther AC, and Owen JS
- Abstract
A mixture of N , N , N '-trisubstituted thiourea and cyclic N , N , N ', N '-tetrasubstituted selenourea precursors were used to synthesize three monolayer thick CdS
1- x Sex nanoplatelets in a single synthetic step. The microstructure of the nanoplatelets could be tuned from homogeneous alloys, to graded alloys to core/crown heterostructures depending on the relative conversion reactivity of the sulfur and selenium precursors. UV-visible absorption and photoluminescence spectroscopy and scanning transmission electron microscopy electron energy loss spectroscopy (STEM-EELS) images demonstrate that the elemental distribution is governed by the relative precursor conversion kinetics. Slow conversion kinetics produced nanoplatelets with larger lateral dimensions, behavior that is characteristic of precursor conversion limited growth kinetics. Across a 10-fold range of reactivity, CdS nanoplatelets have 4× smaller lateral dimensions than CdSe nanoplatelets grown under identical conversion kinetics. The difference in size is consistent with a rate of CdSe growth that is 4× greater than the rate of CdS. The influence of the relative sulfide and selenide growth rates, the duration of the nucleation phase, and the solute composition on the nanoplatelet microstructure are discussed., Competing Interests: There are no conflicts to declare., (This journal is © The Royal Society of Chemistry.)- Published
- 2023
- Full Text
- View/download PDF
24. The Ligand-Surface Interface and Its Influence on Nanoparticle Properties.
- Author
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Nam JM, Owen JS, and Talapin DV
- Published
- 2023
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25. Clinical applications of gene therapy for rare diseases: A review.
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Papaioannou I, Owen JS, and Yáñez-Muñoz RJ
- Subjects
- Humans, Rare Diseases genetics, Rare Diseases therapy, Genetic Therapy, Severe Combined Immunodeficiency genetics, Severe Combined Immunodeficiency therapy, Agammaglobulinemia genetics, Agammaglobulinemia therapy
- Abstract
Rare diseases collectively exact a high toll on society due to their sheer number and overall prevalence. Their heterogeneity, diversity, and nature pose daunting clinical challenges for both management and treatment. In this review, we discuss recent advances in clinical applications of gene therapy for rare diseases, focusing on a variety of viral and non-viral strategies. The use of adeno-associated virus (AAV) vectors is discussed in the context of Luxturna, licenced for the treatment of RPE65 deficiency in the retinal epithelium. Imlygic, a herpes virus vector licenced for the treatment of refractory metastatic melanoma, will be an example of oncolytic vectors developed against rare cancers. Yescarta and Kymriah will showcase the use of retrovirus and lentivirus vectors in the autologous ex vivo production of chimeric antigen receptor T cells (CAR-T), licenced for the treatment of refractory leukaemias and lymphomas. Similar retroviral and lentiviral technology can be applied to autologous haematopoietic stem cells, exemplified by Strimvelis and Zynteglo, licenced treatments for adenosine deaminase-severe combined immunodeficiency (ADA-SCID) and β-thalassaemia respectively. Antisense oligonucleotide technologies will be highlighted through Onpattro and Tegsedi, RNA interference drugs licenced for familial transthyretin (TTR) amyloidosis, and Spinraza, a splice-switching treatment for spinal muscular atrophy (SMA). An initial comparison of the effectiveness of AAV and oligonucleotide therapies in SMA is possible with Zolgensma, an AAV serotype 9 vector, and Spinraza. Through these examples of marketed gene therapies and gene cell therapies, we will discuss the expanding applications of such novel technologies to previously intractable rare diseases., (© 2023 The Authors. International Journal of Experimental Pathology published by John Wiley & Sons Ltd on behalf of Company of the International Journal of Experimental Pathology (CIJEP).)
- Published
- 2023
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26. Type and duration of water stress influence host selection and colonization by exotic ambrosia beetles (Coleoptera: Curculionidae).
- Author
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Ranger CM, Parajuli M, Gresham S, Barnett J, Villani S, Walgenbach J, Baysal-Gurel F, Owen JS Jr, and Reding ME
- Abstract
Fungus-farming ambrosia beetles in the tribe Xyleborini tunnel into plants and trees to establish chambers for cultivating their nutritional fungal mutualists and rearing offspring. Some xyleborine ambrosia beetles preferentially infest and perform better in living but weakened trees. Flood stress predisposes horticultural tree crops to infestation, but the impact of drought stress has not been well studied. Our objectives were to compare the effects of flood stress vs. drought stress on host selection and colonization by xyleborine ambrosia beetles and to assess the duration of flooding. Container-grown Cornus florida L. trees were flood stressed using a pot-in-pot system to submerge the roots in water while drought-stressed conditions were imposed by withholding irrigation and precipitation. When experimental trees were held under field conditions for 14 days, 7.5 × more ambrosia beetles landed on stems of the flood-stressed than on the drought-stressed trees. During two additional experiments over 14 and 22 days, ambrosia beetles tunneled into the flood-stressed trees but not the drought-stressed or standard irrigation trees. By simultaneously deploying trees that were flood stressed for varying lengths of time, it was found that more tunnel entrances, and xyleborine adults and offspring were recovered from trees that were flooded for 1-16 days and 7-22 days than from trees that were flooded for 14-29 days and 28-43 days. These results indicate that acute and severe drought stress does not predispose C. florida to infestation, but flood stress and the duration of flooding influence ambrosia beetle host selection and colonization. Understanding the role of host quality on ambrosia beetle preference behavior will assist with predicting the risk of infestation of these opportunistic insects in horticultural tree crops., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest. The author CR declares that they were an editorial board member of Frontiers at the time of submission. This had no impact on the peer review process and the final decision., (Copyright © 2023 Ranger, Parajuli, Gresham, Barnett, Villani, Walgenbach, Baysal-Gurel, Owen and Reding.)
- Published
- 2023
- Full Text
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27. Microbial Interaction is Among the Key Factors for Isolation of Previous Uncultured Microbes.
- Author
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Yan C, Owen JS, Seo EY, Jung D, and He S
- Subjects
- Biotechnology, Microbial Interactions
- Abstract
Pure cultivation of microbes is still limited by the challenges of microbial uncultivability, with most microbial strains unable to be cultivated under standard laboratory conditions. The experience accumulated from advanced techniques such as in situ cultivation has identified that microbial interactions exist in natural habitats but are absent in laboratory cultures. These microbial interactions are likely one of the key factors in isolating previously uncultured microbes. The need for better knowledge of the mechanisms operating in microbial interactions has led to various experiments that have utilized microbial interactions in different approaches to microbial cultivation. These new attempts to understand microbial interactions not only present a new perspective on microbial uncultivability but also provide an opportunity to access uncultured phylogenetically novel microbes with their potential biotechnology applications. In this review, we focus on studies of the mechanisms of microbial interaction where the growth of other microbes is affected. Additionally, we review some successful applications of microbial interactions in cultivation methods, an approach that can play an important role in the bioprospecting of untapped microbial resources., (© 2023. The Author(s).)
- Published
- 2023
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28. Design Rules for Obtaining Narrow Luminescence from Semiconductors Made in Solution.
- Author
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Nguyen HA, Dixon G, Dou FY, Gallagher S, Gibbs S, Ladd DM, Marino E, Ondry JC, Shanahan JP, Vasileiadou ES, Barlow S, Gamelin DR, Ginger DS, Jonas DM, Kanatzidis MG, Marder SR, Morton D, Murray CB, Owen JS, Talapin DV, Toney MF, and Cossairt BM
- Abstract
Solution-processed semiconductors are in demand for present and next-generation optoelectronic technologies ranging from displays to quantum light sources because of their scalability and ease of integration into devices with diverse form factors. One of the central requirements for semiconductors used in these applications is a narrow photoluminescence (PL) line width. Narrow emission line widths are needed to ensure both color and single-photon purity, raising the question of what design rules are needed to obtain narrow emission from semiconductors made in solution. In this review, we first examine the requirements for colloidal emitters for a variety of applications including light-emitting diodes, photodetectors, lasers, and quantum information science. Next, we will delve into the sources of spectral broadening, including "homogeneous" broadening from dynamical broadening mechanisms in single-particle spectra, heterogeneous broadening from static structural differences in ensemble spectra, and spectral diffusion. Then, we compare the current state of the art in terms of emission line width for a variety of colloidal materials including II-VI quantum dots (QDs) and nanoplatelets, III-V QDs, alloyed QDs, metal-halide perovskites including nanocrystals and 2D structures, doped nanocrystals, and, finally, as a point of comparison, organic molecules. We end with some conclusions and connections, including an outline of promising paths forward.
- Published
- 2023
- Full Text
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29. A targeted liquid cultivation method for previously uncultured non-colony forming microbes.
- Author
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Seo EY, Jung D, Epstein SS, Zhang W, Owen JS, Baba H, Yamamoto A, Harada M, Nakashimada Y, Kato S, Aoi Y, and He S
- Abstract
A large number of microbes are not able to form colonies using agar-plating methods, which is one of the reasons that cultivation based on solid media leaves the majority of microbial diversity in the environment inaccessible. We developed a new Non-Colony-Forming Liquid Cultivation method (NCFLC) that can selectively isolate non-colony-forming microbes that exclusively grow in liquid culture. The NCFLC method involves physically separating cells using dilution-to-extinction (DTE) cultivation and then selecting those that could not grow on a solid medium. The NCFLC was applied to marine samples from a coastal intertidal zone and soil samples from a forest area, and the results were compared with those from the standard direct plating method (SDP). The NCFLC yielded fastidious bacteria from marine samples such as Acidobacteriota, Epsilonproteobacteria, Oligoflexia , and Verrucomicrobiota . Furthermore, 62% of the isolated strains were potential new species, whereas only 10% were novel species from SDP. From soil samples, isolates belonging to Acidobacteriota and Armatimonadota (which are known as rare species among identified isolates) were exclusively isolated by NCFLC. Colony formation capabilities of isolates cultivated by NCFLC were tested using solid agar plates, among which approximately one-third of the isolates were non-colony-forming, approximately half-formed micro-colonies, and only a minority could form ordinary size colonies. This indicates that the majority of the strains cultivated by NCFLC were previously uncultured microbial species unavailable using the SDP method. The NCFCL method described here can serve as a new approach to accessing the hidden microbial dark matter., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2023 Seo, Jung, Epstein, Zhang, Owen, Baba, Yamamoto, Harada, Nakashimada, Kato, Aoi and He.)
- Published
- 2023
- Full Text
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30. Indefinite and bidirectional near-infrared nanocrystal photoswitching.
- Author
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Lee C, Xu EZ, Kwock KWC, Teitelboim A, Liu Y, Park HS, Ursprung B, Ziffer ME, Karube Y, Fardian-Melamed N, Pedroso CCS, Kim J, Pritzl SD, Nam SH, Lohmueller T, Owen JS, Ercius P, Suh YD, Cohen BE, Chan EM, and Schuck PJ
- Abstract
Materials whose luminescence can be switched by optical stimulation drive technologies ranging from superresolution imaging
1-4 , nanophotonics5 , and optical data storage6,7 , to targeted pharmacology, optogenetics, and chemical reactivity8 . These photoswitchable probes, including organic fluorophores and proteins, can be prone to photodegradation and often operate in the ultraviolet or visible spectral regions. Colloidal inorganic nanoparticles6,9 can offer improved stability, but the ability to switch emission bidirectionally, particularly with near-infrared (NIR) light, has not, to our knowledge, been reported in such systems. Here, we present two-way, NIR photoswitching of avalanching nanoparticles (ANPs), showing full optical control of upconverted emission using phototriggers in the NIR-I and NIR-II spectral regions useful for subsurface imaging. Employing single-step photodarkening10-13 and photobrightening12,14-16 , we demonstrate indefinite photoswitching of individual nanoparticles (more than 1,000 cycles over 7 h) in ambient or aqueous conditions without measurable photodegradation. Critical steps of the photoswitching mechanism are elucidated by modelling and by measuring the photon avalanche properties of single ANPs in both bright and dark states. Unlimited, reversible photoswitching of ANPs enables indefinitely rewritable two-dimensional and three-dimensional multilevel optical patterning of ANPs, as well as optical nanoscopy with sub-Å localization superresolution that allows us to distinguish individual ANPs within tightly packed clusters., (© 2023. The Author(s), under exclusive licence to Springer Nature Limited.)- Published
- 2023
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31. Cancer-Associated Fibroblast Heterogeneity, Activation and Function: Implications for Prostate Cancer.
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Owen JS, Clayton A, and Pearson HB
- Subjects
- Male, Humans, Fibroblasts pathology, Carcinogenesis pathology, Cell Transformation, Neoplastic, Tumor Microenvironment physiology, Cancer-Associated Fibroblasts pathology, Prostatic Neoplasms genetics, Prostatic Neoplasms pathology
- Abstract
The continuous remodeling of the tumor microenvironment (TME) during prostate tumorigenesis is emerging as a critical event that facilitates cancer growth, progression and drug-resistance. Recent advances have identified extensive communication networks that enable tumor-stroma cross-talk, and emphasized the functional importance of diverse, heterogeneous stromal fibroblast populations during malignant growth. Cancer-associated fibroblasts (CAFs) are a vital component of the TME, which mediate key oncogenic events including angiogenesis, immunosuppression, metastatic progression and therapeutic resistance, thus presenting an attractive therapeutic target. Nevertheless, how fibroblast heterogeneity, recruitment, cell-of-origin and differential functions contribute to prostate cancer remains to be fully delineated. Developing our molecular understanding of these processes is fundamental to developing new therapies and biomarkers that can ultimately improve clinical outcomes. In this review, we explore the current challenges surrounding fibroblast identification, discuss new mechanistic insights into fibroblast functions during normal prostate tissue homeostasis and tumorigenesis, and illustrate the diverse nature of fibroblast recruitment and CAF generation. We also highlight the promise of CAF-targeted therapies for the treatment of prostate cancer.
- Published
- 2022
- Full Text
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32. What are the relevant sources and factors affecting event mean concentrations (EMCs) of nutrients and sediment in stormwater?
- Author
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Behrouz MS, Yazdi MN, Sample DJ, Scott D, and Owen JS Jr
- Subjects
- Bayes Theorem, Environmental Monitoring methods, Nitrogen analysis, Nutrients, Phosphorus analysis, Rain, Water Movements, Environmental Pollutants, Water Pollutants, Chemical analysis
- Abstract
Urbanization increases runoff, sediment, and nutrient loadings downstream, causing flooding, eutrophication, and harmful algal blooms. Stormwater control measures (SCMs) are used to address these concerns and are designed based on inflow loads. Thus, estimating nutrient and sediment loads is important for meeting restoration objectives. Pollutants accumulate on surfaces during dry periods, making Event Mean Concentration (EMC) a function of antecedent dry period (ADP). An EMC results from wash-off of accumulated pollutants from catchment surface during runoff events. However, several studies found little to no correlation between constituent concentrations in stormwater and ADP. The objective of this study is to verify this finding and discover which climatological or catchment characteristics most significantly affect stormwater quality. Stormwater quality data were obtained from the National Stormwater Quality Database (NSQD), which is the largest data repository of stormwater quality data in the U.S. Bayesian Network Structure Learner (BNSL) was used to assess the relationships between catchment characteristics, climatological information, and stormwater quality for selected land uses. Given the optimal BN structure, it was determined which parameters most affect stormwater quality EMCs. The results demonstrate that both catchment and rain characteristics affected stormwater quality EMCs. Among catchment characteristics, land use (LU) was the most important factor and catchment size was the least. Precipitation depth (P) and duration (D) affected Total Phosphorus (TP), Total Nitrogen (TN), and Total Suspended Solids (TSS). This indicated that it is likely that P and D had a greater influence on stormwater quality more than ADP. P, D, and ADP affected the dissolved constituents of TN (i.e. NO
2 -N/NO3 -N) and TP (i.e. Ortho-P). Compared to other factors (i.e. P and D), the effect of ADP on TSS was negligible. Stormwater quality EMCs related to nitrogen were not affected by catchment slope (S). However, TSS and Ortho-P were influenced by S., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022 The Authors. Published by Elsevier B.V. All rights reserved.)- Published
- 2022
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33. Persistent nucleation and size dependent attachment kinetics produce monodisperse PbS nanocrystals.
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Abécassis B, Greenberg MW, Bal V, McMurtry BM, Campos MP, Guillemeney L, Mahler B, Prevost S, Sharpnack L, Hendricks MP, DeRosha D, Bennett E, Saenz N, Peters B, and Owen JS
- Abstract
Modern syntheses of colloidal nanocrystals yield extraordinarily narrow size distributions that are believed to result from a rapid "burst of nucleation" (La Mer, JACS , 1950, 72 (11), 4847-4854) followed by diffusion limited growth and size distribution focusing (Reiss, J. Chem. Phys. , 1951, 19 , 482). Using a combination of in situ X-ray scattering, optical absorption, and
13 C nuclear magnetic resonance (NMR) spectroscopy, we monitor the kinetics of PbS solute generation, nucleation, and crystal growth from three thiourea precursors whose conversion reactivity spans a 2-fold range. In all three cases, nucleation is found to be slow and continues during >50% of the precipitation. A population balance model based on a size dependent growth law (1/ r ) fits the data with a single growth rate constant ( kG ) across all three precursors. However, the magnitude of the kG and the lack of solvent viscosity dependence indicates that the rate limiting step is not diffusion from solution to the nanoparticle surface. Several surface reaction limited mechanisms and a ligand penetration model that fits data our experiments using a single fit parameter are proposed to explain the results., Competing Interests: There are no conflicts to declare., (This journal is © The Royal Society of Chemistry.)- Published
- 2022
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34. Growth kinetics determine the polydispersity and size of PbS and PbSe nanocrystals.
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Campos MP, De Roo J, Greenberg MW, McMurtry BM, Hendricks MP, Bennett E, Saenz N, Sfeir MY, Abécassis B, Ghose SK, and Owen JS
- Abstract
A library of thio- and selenourea derivatives is used to adjust the kinetics of PbE (E = S, Se) nanocrystal formation across a 1000-fold range ( k
r = 10-1 to 10-4 s-1 ), at several temperatures (80-120 °C), under a standard set of conditions (Pb : E = 1.2 : 1, [Pb(oleate)2 ] = 10.8 mM, [chalcogenourea] = 9.0 mM). An induction delay ( tind ) is observed prior to the onset of nanocrystal absorption during which PbE solute is observed using in situ X-ray total scattering. Density functional theory models fit to the X-ray pair distribution function (PDF) support a Pb2 (μ2 -S)2 (Pb(O2 CR)2 )2 structure. Absorption spectra of aliquots reveal a continuous increase in the number of nanocrystals over more than half of the total reaction time at low temperatures. A strong correlation between the width of the nucleation phase and reaction temperature is observed that does not correlate with the polydispersity. These findings are antithetical to the critical concentration dependence of nucleation that underpins the La Mer hypothesis and demonstrates that the duration of the nucleation period has a minor influence on the size distribution. The results can be explained by growth kinetics that are size dependent, more rapid at high temperature, and self limiting at low temperatures., Competing Interests: The authors declare no competing financial interest., (This journal is © The Royal Society of Chemistry.)- Published
- 2022
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35. Relations between absorption, emission, and excited state chemical potentials from nanocrystal 2D spectra.
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Ryu J, Park SD, Baranov D, Rreza I, Owen JS, and Jonas DM
- Abstract
For quantum-confined nanomaterials, size dispersion causes a static broadening of spectra that has been difficult to measure and invalidates all-optical methods for determining the maximum photovoltage that an excited state can generate. Using femtosecond two-dimensional (2D) spectroscopy to separate size dispersion broadening of absorption and emission spectra allows a test of single-molecule generalized Einstein relations between such spectra for colloidal PbS quantum dots. We show that 2D spectra and these relations determine the thermodynamic standard chemical potential difference between the lowest excited and ground electronic states, which gives the maximum photovoltage. Further, we find that the static line broadening from many slightly different quantum dot structures allows single-molecule generalized Einstein relations to determine the average single-molecule linewidth from Stokes' frequency shift between ensemble absorption and emission spectra., (Copyright © 2021 The Authors, some rights reserved; exclusive licensee American Association for the Advancement of Science. No claim to original U.S. Government Works. Distributed under a Creative Commons Attribution NonCommercial License 4.0 (CC BY-NC).)
- Published
- 2021
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36. Accessing previously uncultured marine microbial resources by a combination of alternative cultivation methods.
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Jung D, Liu B, He X, Owen JS, Liu L, Yuan Y, Zhang W, and He S
- Subjects
- Culture Media, Phylogeny, RNA, Ribosomal, 16S, Bacteria genetics, Bacteriological Techniques
- Abstract
Few microbes can grow under laboratory conditions, highlighting the fact that the majority of microbes in environment are still uncultured and untapped resources. This study used alternative cultivation methods, diffusion chambers (DC), dilution-to-extinction culture (DTE) and modified agar preparation step (PS media) to cultivate previously uncultured marine bacterial species. These methods were applied to samples from a coastal intertidal zone, and the results were compared with those from standard direct plating (SDP) cultivation. Among the strains isolated with DC, DTE and PS media methods, 28%, 48% and 33% were novel species, respectively, while the SDP method resulted in the isolation of only 9% of novel species. Most isolates were unique to the method used for their cultivation. This implies that each method is selective in its own way, which is different from SDP, thus able to access species that are difficult to obtain using conventional approaches. Comparing the diversity showed that 75 genera were recovered by the alternative methods, 2.7 times higher than that of the SDP cultivation, which constituted 45% of total diversity from culture-independent sequencing. We conclude that combining alternative cultivation methods represents a highly promising key for accessing 'microbial dark matter'., (© 2021 The Authors. Microbial Biotechnology published by John Wiley & Sons Ltd and Society for Applied Microbiology.)
- Published
- 2021
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37. Apolipoprotein E polymorphism influences orthotopic liver transplantation outcomes in patients with hepatitis C virus-induced liver cirrhosis.
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Nascimento JCR, Pereira LC, Rêgo JMC, Dias RP, Silva PGB, Sobrinho SAC, Coelho GR, Brasil IRC, Oliveira-Filho EF, Owen JS, Toniutto P, and Oriá RB
- Subjects
- Adult, Aged, Apolipoproteins E genetics, Cohort Studies, Female, Hepacivirus genetics, Humans, Liver Cirrhosis diagnosis, Liver Cirrhosis genetics, Liver Cirrhosis surgery, Male, Middle Aged, Neoplasm Recurrence, Local, Recurrence, Hepatitis C complications, Hepatitis C genetics, Liver Neoplasms, Liver Transplantation adverse effects
- Abstract
Background: Hepatitis C virus (HCV) infection is responsible for a chronic liver inflammation, which may cause end-stage liver disease and hepatocellular carcinoma. Apolipoprotein E (protein: ApoE, gene: APOE ), a key player in cholesterol metabolism, is mainly synthesized in the liver and APOE polymorphisms may influence HCV-induced liver damage., Aim: To determine whether APOE alleles affect outcomes in HCV-infected patients with liver cirrhosis following orthotopic liver transplantation (OLT)., Methods: This was a cohort study in which 179 patients, both genders and aged 34-70 years, were included before or after (up to 10 years follow-up) OLT. Liver injury severity was assessed using different criteria, including METAVIR and models for end-stage liver disease. APOE polymorphisms were analyzed by quantitative real-time polymerase chain reaction., Results: The APOE3 allele was the most common (67.3%). In inflammation severity of biopsies from 89 OLT explants and 2 patients in pre-transplant, the degree of severe inflammation (A3F4, 0.0%) was significantly less frequent than in patients with minimal and moderate degree of inflammation (≤ A2F4, 16.2%) P = 0.048, in patients carrying the APOE4 allele when compared to non- APOE4 . In addition, a significant difference was also found (≤ A2F4, 64.4% vs A3F4, 0.0%; P = 0.043) and (A1F4, 57.4% vs A3F4, 0.0%; P = 0.024) in APOE4 patients when compared to APOE3 carriers. The fibrosis degree of the liver graft in 8 of 91 patients and the lack of the E4 allele was associated with more moderate fibrosis (F2) ( P = 0.006)., Conclusion: Our results suggest that the E4 allele protects against progression of liver fibrosis and degree of inflammation in HCV-infected patients., Competing Interests: Conflict-of-interest statement: The authors have no conflicts of interest., (©The Author(s) 2021. Published by Baishideng Publishing Group Inc. All rights reserved.)
- Published
- 2021
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38. Au/TiO 2 -Catalyzed Benzyl Alcohol Oxidation on Morphologically Precise Anatase Nanoparticles.
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Mahdavi-Shakib A, Sempel J, Hoffman M, Oza A, Bennett E, Owen JS, Rahmani Chokanlu A, Frederick BG, and Austin RN
- Abstract
Au nanoparticles (NP) on TiO
2 have been shown to be effective catalysts for selective oxidation reactions by using molecular oxygen. In this work, we have studied the influence of support morphology on the catalytic activity of Au/TiO2 catalysts. Two TiO2 anatase supports, a nanoplatelet-shaped material with predominantly the {001} facet exposed and a truncated bipyramidal-shaped nanoparticle with predominantly the {101} facet exposed, were prepared by using a nonaqueous solvothermal method and characterized by using DRIFTS, XPS, and TEM. Au nanoparticles were deposited on the supports by using the deposition-precipitation method, and particle sizes were determined by using STEM. Au nanoparticles were smaller on the support with the majority of the {101} facet exposed. The resulting materials were used to catalyze the aerobic oxidation of benzyl alcohol and trifluoromethylbenzyl alcohol. Support morphology impacts the catalytic activity of Au/TiO2 ; reaction rates for reactions catalyzed by the predominantly {101} material were higher. Much of the increased reactivity can be explained by the presence of smaller Au particles on the predominantly {101} material, providing more Au/TiO2 interface area, which is where catalysis occurs. The remaining modest differences between the two catalysts are likely due to geometric effects as Hammett slopes show no evidence for electronic differences between the Au particles on the different materials.- Published
- 2021
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39. Performance of Spherical Quantum Well Down Converters in Solid State Lighting.
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Rreza I, Yang H, Hamachi L, Campos M, Hull T, Treadway J, Kurtin J, Chan EM, and Owen JS
- Abstract
We report the color conversion performance of amber and red emitting quantum dots (QDs) on InGaN solid-state lighting (SSL) light emitting diode (LED) packages. Spherical quantum well (SQW) architectures (CdS/CdSe
1- x Sx /CdS) were prepared using a library of thio- and selenourea synthesis reagents and high throughput synthesis robotics. CdS/CdSe1- x Sx QDs with narrow luminescence bands were coated with thick CdS shells (thickness = 1.6-7.5 nm) to achieve photoluminescence quantum yields (PLQY) up to 88% at amber and red emission wavelengths (λmax = 600-642 nm, FWHM < 45 nm). The photoluminescence from SQWs encapsulated in silicone and deposited on LED packages was monitored under accelerated aging conditions (oven temperature = 85 °C, relative humidity = 5-85%, blue optical power density = 3-45 W/cm2 ) by monitoring the red photon output over several hundred hours of continuous operation. The growth of a ZnS shell on the SQW surface increases the stability under long-term operation but also reduces the PLQY, especially of SQWs with thick CdS shells. The results illustrate that the outer ZnS shell layer is key to optimizing the PLQY and the long-term stability of QDs during operation on SSL packages.- Published
- 2021
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40. Retrospective Analysis Using Pharmacokinetic/Pharmacodynamic Modeling and Simulation Offers Improvements in Efficiency of the Design of Volunteer Infection Studies for Antimalarial Drug Development.
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Andrews KA, Owen JS, McCarthy J, Wesche D, Gobeau N, Grasela TH, and Möhrle JJ
- Subjects
- Antimalarials pharmacokinetics, Cohort Studies, Computer Simulation, Dose-Response Relationship, Drug, Healthy Volunteers, Humans, Malaria parasitology, Plasmodium pathogenicity, Research Design, Retrospective Studies, Antimalarials administration & dosage, Clinical Trials, Phase I as Topic, Malaria drug therapy, Models, Biological, Plasmodium drug effects
- Abstract
Volunteer infection studies using the induced blood stage malaria (IBSM) model have been shown to facilitate antimalarial drug development. Such studies have traditionally been undertaken in single-dose cohorts, as many as necessary to obtain the dose-response relationship. To enhance ethical and logistic aspects of such studies, and to reduce the number of cohorts needed to establish the dose-response relationship, we undertook a retrospective in silico analysis of previously accrued data to improve study design. A pharmacokinetic (PK)/pharmacodynamic (PD) model was developed from initial fictive-cohort data for OZ439 (mixing the data of the three single-dose cohorts as: n = 2 on 100 mg, 2 on 200 mg, and 4 on 500 mg). A three-compartment model described OZ439 PKs. Net growth of parasites was modeled using a Gompertz function and drug-induced parasite death using a Hill function. Parameter estimates for the PK and PD models were comparable for the multidose single-cohort vs. the pooled analysis of all cohorts. Simulations based on the multidose single-cohort design described the complete data from the original IBSM study. The novel design allows for the ascertainment of the PK/PD relationship early in the study, providing a basis for rational dose selection for subsequent cohorts and studies., (© 2020 The Authors. Clinical and Translational Science published by Wiley Periodicals LLC on behalf of the American Society for Clinical Pharmacology and Therapeutics.)
- Published
- 2021
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41. Nutrient and pesticide remediation using a two-stage bioreactor-adsorptive system under two hydraulic retention times.
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Abdi DE, Owen JS Jr, Brindley JC, Birnbaum AC, Wilson PC, Hinz FO, Reguera G, Lee JY, Cregg BM, Kort DR, and Fernandez RT
- Subjects
- Bioreactors, Nitrates, Nutrients, Denitrification, Pesticides
- Abstract
Nutrients and pesticides in agricultural runoff contribute to the degradation of water resources. Nitrates and phosphates can be remediated through the use of treatment systems such as woodchip bioreactors and adsorbent aggregate filters; however, concerns remain over potential effects of pesticides on nutrient removal efficiency in these systems. To test this, we designed laboratory-scale woodchip bioreactors equipped with secondary adsorbent aggregate filters and investigated the capacity of these systems to remediate nutrients when operated under two hydraulic retention times (HRT) and in the presence of commonly used pesticides. The woodchip bioreactors effectively removed over 99% of nitrate per day when operated under a 72 h hydraulic retention time, with the secondary expanded shale aggregate filters consistently reducing phosphate concentrations by 80-87%. Treatment efficacy of both systems was maintained in the presence of the insecticide chlorpyrifos. Reducing HRT in the bioreactors to 21 min decreased nitrate removal efficiency; however, the insecticides bifenthrin, chlorpyrifos, and the herbicide oxyfluorfen were reduced by 76%, 63%, and 31%, respectively. Cultivation approaches led to the isolation of 45 different species from the woodchip bioreactors operated under a 21 min HRT, with Bacillus species being the most prevalent throughout the treatment. By contrast, pesticide application decreased the number and diversity of Bacillus isolates and enriched for Pseudomonas and Exiguobacterium species. Woodchip bioreactors and adsorbent aggregate filters provide effective treatment platforms to remediate agrochemicals, where they maintain treatment efficacy in the presence of pesticides and can be modulated through HRT management to achieve environmental and operational water quality goals., (Copyright © 2019 Elsevier Ltd. All rights reserved.)
- Published
- 2020
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42. A Brazilian regional basic diet-induced chronic malnutrition drives liver inflammation with higher ApoA-I activity in C57BL6J mice.
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Santos MJS, Canuto KM, de Aquino CC, Martins CS, Brito GAC, Pessoa TMRP, Bertolini LR, de Sá Carneiro I, Pinto DV, Nascimento JCR, da Silva BB, Valença JT Jr, Guedes MIF, Owen JS, and Oriá RB
- Subjects
- Animals, Apolipoprotein A-I metabolism, Brazil, Chronic Disease, Humans, Inflammation blood, Inflammation pathology, Liver metabolism, Male, Malnutrition blood, Malnutrition pathology, Mice, Mice, Inbred C57BL, Apolipoprotein A-I blood, Diet adverse effects, Inflammation metabolism, Malnutrition metabolism
- Abstract
Malnutrition is still considered endemic in many developing countries. Malnutrition-enteric infections may cause lasting deleterious effects on lipid metabolism, especially in children living in poor settings. The regional basic diet (RBD), produced to mimic the Brazilian northeastern dietary characteristics (rich in carbohydrate and low in protein) has been used in experimental malnutrition models, but few studies have explored the effect of chronic RBD on liver function, a central organ involved in cholesterol metabolism. This study aimed to investigate whether RBD leads to liver inflammatory changes and altered reverse cholesterol metabolism in C57BL6/J mice compared to the control group, receiving a standard chow diet. To evaluate liver inflammation, ionized calcium-binding adapter protein-1 (IBA-1) positive cell counting, interleukin (IL)-1β immunohistochemistry, and tumor necrosis factor (TNF)-α and IL-10 transcription levels were analyzed. In addition, we assessed reverse cholesterol transport by measuring liver apolipoprotein (Apo)E, ApoA-I, and lecithin-cholesterol acyltransferase (LCAT) by RT-PCR. Furthermore, serum alanine aminotransferase (ALT) was measured to assess liver function. RBD markedly impaired body weight gain compared with the control group (P<0.05). Higher hepatic TNF-α (P<0.0001) and IL-10 (P=0.001) mRNA levels were found in RBD-challenged mice, although without detectable non-alcoholic fatty liver disease. Marked IBA-1 immunolabeling and increased number of positive-IBA-1 cells were found in the undernourished group. No statistical difference in serum ALT was found. There was also a significant increase in ApoA mRNA expression in the undernourished group, but not ApoE and LCAT, compared with the control. Altogether our findings suggested that chronic RBD-induced malnutrition leads to liver inflammation with increased ApoA-I activity.
- Published
- 2020
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43. Precursor reaction kinetics control compositional grading and size of CdSe 1- x S x nanocrystal heterostructures.
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Hamachi LS, Yang H, Jen-La Plante I, Saenz N, Qian K, Campos MP, Cleveland GT, Rreza I, Oza A, Walravens W, Chan EM, Hens Z, Crowther AC, and Owen JS
- Abstract
We report a method to control the composition and microstructure of CdSe
1- x Sx nanocrystals by the simultaneous injection of sulfide and selenide precursors into a solution of cadmium oleate and oleic acid at 240 °C. Pairs of substituted thio- and selenoureas were selected from a library of compounds with conversion reaction reactivity exponents ( kE ) spanning 1.3 × 10-5 s-1 to 2.0 × 10-1 s-1 . Depending on the relative reactivity ( kSe / kS ), core/shell and alloyed architectures were obtained. Growth of a thick outer CdS shell using a syringe pump method provides gram quantities of brightly photoluminescent quantum dots (PLQY = 67 to 90%) in a single reaction vessel. Kinetics simulations predict that relative precursor reactivity ratios of less than 10 result in alloyed compositions, while larger reactivity differences lead to abrupt interfaces. CdSe1- x Sx alloys ( kSe / kS = 2.4) display two longitudinal optical phonon modes with composition dependent frequencies characteristic of the alloy microstructure. When one precursor is more reactive than the other, its conversion reactivity and mole fraction control the number of nuclei, the final nanocrystal size at full conversion, and the elemental composition. The utility of controlled reactivity for adjusting alloy microstructure is discussed.- Published
- 2019
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44. Water quality characterization of storm and irrigation runoff from a container nursery.
- Author
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Yazdi MN, Sample DJ, Scott D, Owen JS, Ketabchy M, and Alamdari N
- Abstract
Commercial nurseries grow specialty crops for resale using a variety of methods, including containerized production, utilizing soilless substrates, on a semipervious production surface. These "container" nurseries require daily water application and continuous availability of mineral nutrients. These factors can generate significant nutrients [total nitrogen (TN), and total phosphorus (TP)] and sediment [total suspended solids (TSS)] in runoff, potentially contributing to eutrophication of downstream water bodies. Runoff is collected in large ponds known as tailwater recovery basins for treatment and reuse or discharge to receiving streams. We characterized TSS, TN, and TP, electrical conductivity (EC), and pH in runoff from a 5.2 ha production portion of a 200-ha commercial container nursery during storm and irrigation events. Results showed a direct correlation between TN and TP, runoff and TSS, TN and EC, and between flow and pH. The Storm Water Management Model (SWMM) was used to characterize runoff quantity and quality of the site. We found during irrigation events that simulated event mean concentrations (EMCs) of TSS, TN, and TP were 30, 3.1 and 0.35 mg·L
-1 , respectively. During storm events, TSS, TN and TP EMCs were 880, 3.7, and 0.46 mg·L-1 , respectively. EMCs of TN and TP were similar to that of urban runoff; however, the TSS EMC from nursery runoff was 2-4 times greater. The average loading of TSS, TN and TP during storm events was approximately 900, 35 and 50 times higher than those of irrigation events, respectively. Based on a 10-year SWMM simulation (2008-2018) of runoff from the same nursery, annual TSS, TN and TP load per ha during storm events ranged from 9230 to 13,300, 65.8 to 94.0 and 9.00 to 12.9 kg·ha-1 ·yr-1 , respectively. SWMM was able to characterize runoff quality and quantity reasonably well. Thus, it is suitable for characterizing runoff loadings from container nurseries., (Copyright © 2019 Elsevier B.V. All rights reserved.)- Published
- 2019
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45. Dynamic emission Stokes shift and liquid-like dielectric solvation of band edge carriers in lead-halide perovskites.
- Author
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Guo Y, Yaffe O, Hull TD, Owen JS, Reichman DR, and Brus LE
- Abstract
Lead-halide perovskites have emerged as promising materials for photovoltaic and optoelectronic applications. Their significantly anharmonic lattice motion, in contrast to conventional harmonic semiconductors, presents a conceptual challenge in understanding the genesis of their exceptional optoelectronic properties. Here we report a strongly temperature dependent luminescence Stokes shift in the electronic spectra of both hybrid and inorganic lead-bromide perovskite single crystals. This behavior stands in stark contrast to that exhibited by more conventional crystalline semiconductors. We correlate the electronic spectra with the anti-Stokes and Stokes Raman vibrational spectra. Dielectric solvation theories, originally developed for excited molecules dissolved in polar liquids, reproduce our experimental observations. Our approach, which invokes a classical Debye-like relaxation process, captures the dielectric response originating from the incipient anharmonicity of the LO phonon at about 20 meV (160 cm
-1 ) in the lead-bromide framework. We reconcile this liquid-like model incorporating thermally-activated dielectric solvation with more standard solid-state theories of the emission Stokes shift in crystalline semiconductors.- Published
- 2019
- Full Text
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46. Size-Dependent Lattice Dynamics of Atomically Precise Cadmium Selenide Quantum Dots.
- Author
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Shi C, Beecher AN, Li Y, Owen JS, Leu BM, Said AH, Hu MY, and Billinge SJL
- Abstract
Material properties depend sensitively on the atomic arrangements and atomic bonding, but these are notoriously difficult to measure in nanosized atomic clusters due to the small size of the objects and the challenge of obtaining bulk samples of identical clusters. Here, we have combined the recent ability to make gram quantities of identical semiconductor quantum-dot nanoparticles with the ability to measure lattice dynamics on small sample quantities of hydrogenated materials using high energy resolution inelastic x-ray scattering, to measure the size dependence of the phonon density of states in CdSe quantum dots. The fact that we have atomically precise structural models for these nanoparticles allows the calculation of the phonon density of states using density functional theory, providing both experimental and theoretical confirmations of the important role that the inertia of the surface capping species plays on determining the lattice dynamics.
- Published
- 2019
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47. Anthracene as a Launchpad for a Phosphinidene Sulfide and for Generation of a Phosphorus-Sulfur Material Having the Composition P 2 S, a Vulcanized Red Phosphorus That Is Yellow.
- Author
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Transue WJ, Nava M, Terban MW, Yang J, Greenberg MW, Wu G, Foreman ES, Mustoe CL, Kennepohl P, Owen JS, Billinge SJL, Kulik HJ, and Cummins CC
- Subjects
- Color, Models, Molecular, Molecular Conformation, Anthracenes chemistry, Phosphorus chemistry, Sulfides chemistry, Sulfur chemistry
- Abstract
Thermolysis of a pair of dibenzo-7-phosphanorbornadiene compounds is shown to lead to differing behaviors: phosphinidene sulfide release and formation of amorphous P
2 S. These compounds,t BuP(S)A (1, A = C14 H10 or anthracene; 59% isol. yield) and HP(S)A (2; 63%), are available through thionation oft BuPA and the new secondary phosphine HPA (5), prepared from Me2 NPA and DIBAL-H in 50% yield. Phosphinidene sulfide [t BuP═S] transfer is shown to proceed efficiently from 1 to 2,3-dimethyl-1,3-butadiene to form Diels-Alder product 3 with a zero-order dependence on diene. Platinum complex (Ph3 P)2 Pt(η2 -t BuPS) (4, 47%) is also accessed from 1 and structurally characterized. In contrast, heating parent species 2 (3 h, 135 °C) under vacuum instead produces an insoluble, nonvolatile yellow residual material 6 of composition P2 S that displays semiconductor properties with an optical band gap of 2.4 eV. Material 6 obtained in this manner from molecular precursor 2 is in a poorly characterized portion of the phosphorus-sulfur phase diagram and has therefore been subjected to a range of spectroscopic techniques to gain structural insight. X-ray spectroscopic and diffraction techniques, including Raman, XANES, EXAFS, and PDF, reveal 6 to have similarities with related compounds including P4 S3 , Hittorf's violet phosphorus. Various possible structures have been explored as well using quantum chemical calculations under the constraint that each phosphorus atom is trivalent with no terminal sulfide groups, and each sulfur atom is divalent. The structural conclusions are supported by data from phosphorus-31 magic angle spinning (MAS) solid state NMR spectroscopy, bolstering the structural comparisons to other phosphorus-sulfur systems while excluding the formulation of P2 S as a simple mixture of P4 S3 and phosphorus.- Published
- 2019
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48. Flexible Nanopipettes for Minimally Invasive Intracellular Electrophysiology In Vivo.
- Author
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Jayant K, Wenzel M, Bando Y, Hamm JP, Mandriota N, Rabinowitz JH, Plante IJ, Owen JS, Sahin O, Shepard KL, and Yuste R
- Subjects
- Animals, Mice, Electrophysiological Phenomena genetics, Electrophysiology methods
- Abstract
Intracellular recordings in vivo remains the best technique to link single-neuron electrical properties to network function. Yet existing methods are limited in accuracy, throughput, and duration, primarily via washout, membrane damage, and movement-induced failure. Here, we introduce flexible quartz nanopipettes (inner diameters of 10-25 nm and spring constant of ∼0.08 N/m) as nanoscale analogs of traditional glass microelectrodes. Nanopipettes enable stable intracellular recordings (seal resistances of 500 to ∼800 MΩ, 5 to ∼10 cells/nanopipette, and duration of ∼1 hr) in anaesthetized and awake head-restrained mice, exhibit minimal diffusional flux, and facilitate precise recording and stimulation. When combined with quantum-dot labels and microprisms, nanopipettes enable two-photon targeted electrophysiology from both somata and dendrites, and even paired recordings from neighboring neurons, while permitting simultaneous population imaging across cortical layers. We demonstrate the versatility of this method by recording from parvalbumin-positive (Pv) interneurons while imaging seizure propagation, and we find that Pv depolarization block coincides with epileptic spread. Flexible nanopipettes present a simple method to procure stable intracellular recordings in vivo., (Copyright © 2018 The Authors. Published by Elsevier Inc. All rights reserved.)
- Published
- 2019
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49. Hydrogel and membrane scaffold formulations of Frutalin (breadfruit lectin) within a polysaccharide galactomannan matrix have potential for wound healing.
- Author
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de Sousa FD, Vasconselos PD, da Silva AFB, Mota EF, da Rocha Tomé A, Mendes FRDS, Gomes AMM, Abraham DJ, Shiwen X, Owen JS, Lourenzoni MR, Campos AR, Moreira RA, and Monteiro-Moreira ACO
- Subjects
- Animals, Anti-Infective Agents chemistry, Anti-Infective Agents pharmacology, Cell Line, Galactose analogs & derivatives, Humans, Mice, Models, Molecular, Protein Conformation, Toll-Like Receptor 4 chemistry, Toll-Like Receptor 4 metabolism, Biocompatible Materials chemistry, Biocompatible Materials pharmacology, Galectins chemistry, Hydrogels chemistry, Mannans chemistry, Membranes, Artificial, Wound Healing drug effects
- Abstract
Plant lectins are carbohydrate-binding proteins, which can interact with cell surfaces to initiate anti-inflammatory pathways, as well as immunomodulatory functions. Here, we have extracted, purified and part-characterized the bioactivity of Jacalin, Frutalin, DAL and PNA, before evaluating their potential for wound healing in cultured human skin fibroblasts. Only Frutalin stimulated fibroblast migration in vitro, prompting further studies which established its low cytotoxicity and interaction with TLR4 receptors. Frutalin also increased p-ERK expression and stimulated IL-6 secretion. The in vivo potential of Frutalin for wound healing was then assessed in hybrid combination with the polysaccharide galactomannan, purified from Caesalpinia pulcherrima seeds, using both hydrogel and membrane scaffolds formulations. Physical-chemical characterization of the hybrid showed that lectin-galactomannan interactions increased the pseudoplastic behaviour of solutions, reducing viscosity and increasing Frutalin's concentration. Furthermore, infrared spectroscopy revealed -OH band displacement, likely caused by interaction of Frutalin with galactose residues present on galactomannan chains, while average membrane porosity was 100 μm, sufficient to ensure water vapor permeability. Accelerated angiogenesis and increased fibroblast and keratinocyte proliferation were observed with the optimal hybrid recovering the lesioned area after 11 days. Our findings indicate Frutalin as a biomolecule with potential for tissue repair, regeneration and chronic wound healing., (Copyright © 2018. Published by Elsevier B.V.)
- Published
- 2019
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50. Data on floating treatment wetland aided nutrient removal from agricultural runoff using two wetland species.
- Author
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Spangler JT, Sample DJ, Fox LJ, Owen JS Jr, and White SA
- Abstract
The data presented in this article are related to the research article entitled "Floating treatment wetland aided nutrient removal from agricultural runoff using two wetland species" (Spangler et al., 2018). This Data in Brief article provides data on concentrations of common ions, macro- and micro-nutrients and metals every other week during a floating treatment wetland (FTW) mesocosm experiment, and macro- and micro-nutrient contents in cumulative plant tissues, data on continuously monitored water temperature, and nitrogen and phosphorus removal curves assessed every other week. The full data set is made available to enable critical or extended analysis of the research.
- Published
- 2018
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