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Chinese Journal of Polymer Science 2004年第2期22卷 195-204页

作者： Kelly A. davis Krzysztof Matyjaszewski Center for Macromolecular Engineering Department of Chemistry Carnegie Mellon University 4400 Fifth Ave.Pittsburgh Pennsylvania 15213 USACenter for Macromolecular Engineering Department of Chemistry Carnegie Mellon University 4400 Fifth Ave.Pittsburgh Pennsylvania 15213 USA

The polymerization of n-butyl methacrylate was investigated using the Atom Transfer radical Polymerization technique with CuBr and CuCl/N,N,N',N',N'-pentamethyldiethylenetriamine catalytic systems. Various combinations of catalyst systems and initiators were utilized in order to optimize the polymerization conditions and to obtain well-defined polymers (i.e. controlled molecular weights and low polydispersities). It has been found that the optimal initiator for this system is a chlorine-based initiator, when the catalyst used is a salt in conjunction with the N,N,N',N',N'- pentamethyldiethylenetriamine ligand. Bromine-based initiators tend to result in large amounts of initial termination, leading to polymers with less than ideal chain end functionality, even if CuCl is used as the species to invoke the halogen exchange. Additionally, the effects of the polymerization temperature, species and the initiator structure were determined.

关键词： ATrP Atom transfer radical polymerization Controlled/living radical polymerization Butyl methacrylate Pentamethyldiethylenetriamine

rumen microbial degradation of bromoform from red seaweed(Asparagopsis taxiformis)and the impact on rumen fermentation and methanogenic archaea

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Journal of Animal Science and Biotechnology 2024年第1期15卷 412-426页

作者： Pedro romero Alejandro Belanche Elisabeth Jiménez rafael Hueso Eva ramos-Morales Joan King Salwen Ermias Kebreab David r.Yáñez-ruiz Estacion Experimental del Zaidin Consejo Superior de Investigaciones Cientificas(CSIC)Profesor Albareda 1Granada 18008Spain Department of Animal Production and Food Sciences University of ZaragozaMiguel Servet 177Saragossa 50013Spain Blue Ocean Barns Inc. Redwood CityCAUSA Department of Animal Science University of CaliforniaDavisCA 95618USA

Background The red macroalgae Asparagopsis is an effective methanogenesis inhibitor due to the presence of halogenated methane(CH_(4))analogues,primarily bromoform(CHBr_(3)).This study aimed to investigate the degradation process of CHBr3 from A taxiformis in the rumen and whether this process is *** in vitro batch culture system was used according to a 2×2 factorial design,assessing two A taxiformis inclusion rates[0(CTL)and 2%DM diet(AT)]and two diets[high-concentrate(HC)and high-forage diet(HF)].Incubations lasted for 72 h and samples of headspace and fermentation liquid were taken at 0,0.5,1,3,6,8,12,16,24,48 and 72 h to assess the pattern of degradation of CHBr_(3) into dibromomethane(CH_(2)Br_(2))and fermentation ***,an in vitro experiment with pure cultures of seven methanogens strains(Methanobrevibacter smithii,Methanobrevibacter ruminantium,Methanosphaera stadtmanae,Methanosarcina barkeri,Methanobrevibacter millerae,Methanorhermobacter wolfei and Methanobacterium mobile)was conducted to test the effects of increasing concentrations of CHBr3(0.4,2,10and 50μmol/L).results The addition of AT significantly decreased CH_(4) production(P=0.002)and the acetate:propionate ratio(P=0.003)during a 72-h *** concentrations of CHBr_(3) showed a rapid decrease with nearly 90%degraded within the first 3 h of *** the contrary,CH_(2)Br_(2) concentration quickly increased during the first 6 h and then gradually decreased towards the end of the *** CHBr_(3) degradation nor CH_(2)Br_(2) synthesis were affected by the type of diet used as substrate,suggesting that the fermentation rate is not a driving factor involved in CHBr_(3)*** in vitro culture of methanogens showed a dose-response effect of CHBr3 by inhibiting the growth of ***,***,***,***,***,***,and *** The present work demonstrated that CHBr_(3) from *** is quickly degrad

关键词： Bromoform metabolism Dibromomethane metabolism Methane mitigation Methanogens rumen microbiota Seaweed

DISCONTINUOUS GALErKIN CALCULATIONS FOr A NONLINEAr PDE MODEL OF DNA TrANSCrIPTION WITH SHOrT, TrANSIENT AND FrEQUENT PAUSING

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Journal of Computational Mathematics 2014年第6期32卷 601-629页

作者： Lisa davis Tomas Gedeon Department of Mathematical Sciences Montana State University P.O. Box 172400 Bozeman MT 59717

A discontinuous Galerkin finite element method is used to approximate solutions to a classical traffic flow PDE. This PDE is used to model the biological process of transcription; the process of transferring genetic information from DNA either to mrNA or to rrNA. The transcription process is punctuated by short, frequent rNAP pauses which are incorporated into the model as traffic lights. These pauses cause a delay in the average transcription process. The DG solution of the nonlinear model is used to calculate the delay and to determine the effect of the pauses on the average transcription time. Numerical error measurements between the DG solution and the true solution （derived by the method of characteristics） are given for a simple model problem. It shows an excellent agreement in a neighborhood away from the shocks as well as C9（Ax） convergence for the delay calculation. Preliminary parameter studies indicate that in a system with multiple pauses both the location and time duration of the pauses can significantly affect the average delay experienced by an rNAP.

关键词： Discontinuous Galerkin finite element method Transcription LWr traffic flowmodel.

Biomarkers for diet and cancer prevention research:potentials and challenges

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Acta Pharmacologica Sinica 2007年第9期28卷 1262-1273页

作者： Cindy D davis John A MILNEr Nutritional Science research GroupNational Cancer InstituterockvilleMD 20892USA

As cancer incidence is projected to increase for decades there is a need for effec-tive preventive ***,evidence continues to mount that alteringdietary habits is an effective and cost-efficient approach for reducing cancer riskand for modifying the biological behavior of ***,validated andsensitive biomarkers,including those that reliably evaluate"intake"or exposureto a specific food or bioactive component,that assess one or more specific bio-logical"effects"that are linked to cancer,and that effectively predict individual"susceptibility"as a function of nutrient-nutrient interactions and genetics,arefundamental to evaluating who will benefit most from dietary *** must be readily accessible,easily and reliably assayed,and predictiveof a key process(es) involved in *** response to a food is determined notonly by the effective concentration of the bioactive food component(s) reachingthe target tissue,but also by the amount of the target requiring ***,this threshold response to foods and their components will vary from indi-vidual to *** key to understanding a personalized response is a greaterknowledge of nutrigenomics,proteomics and metabolomics.

关键词： exposure biomarker effect biomarker susceptibility biomarker nutrigenomics

DNA origami mediated electrically connected metal–semiconductor junctions

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Nano research 2020年第5期13卷 1419-1426页

作者： Basu r.Aryal Dulashani r.ranasinghe Tyler r.Westover Diana G.Calvopia robert C.davis John N.Harb Adam T.Woolley Department of Chemistry and Biochemistry Brigham Young UniversityProvoUT 84602USA Department of Chemical Engineering Brigham Young UniversityProvoUT 84602USA Department of Physics and Astronomy Brigham Young UniversityProvoUT 84602USA

DNA-based nanofabrication of inorganic nanostructures has potential application in electronics,catalysis,and *** DNA metallization has generated conductive DNA-assembled nanostructures;however,the use of semiconductors and the development of well-connected nanoscale metal-semiconductor junctions on DNA nanostructures are still at an early ***,we report the first fabrication of multiple electrically connected metal-semiconductor junctions on individual DNA origami by location-specific binding of gold and tellurium *** attachment to DNA origami was via DNA hybridization for Au and by electrostatic interaction for *** gold plating was used to create nanoscale metal-semiconductor interfaces by filling the gaps between Au and Te ***-point electrical characterization indicated that the Au-Te-Au junctions were electrically connected,with current-voltage properties consistent with a Schottky ***-based nanofabrication of metal-semiconductor junctions opens up potential opportunities in nanoelectronics,demonstrating the power of this bottom-up approach.

关键词： current-voltage measurement DNA nanofabrication electroless plating gold nanorods nanoelectronics tellurium nanorods

Do black-furred animals compensate for high solar absorption with smaller hairs？ A test with a polymorphic squirrel species

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Current Zoology 2011年第6期57卷 731-736页

作者： Melanie A. FrATTO Andrew K. davis Odum School of Ecology The University of Georgia Athens GA USA 30602

In polymorphic mammalian species that display multiple color forms, those with dark, or melanic pelage would be prone to overheating, especially if they live in warm climates, because their fur absorbs solar energy at a higher rate. However, experimental studies indicate that certain physical properties of fur of dark individuals appear to prevent, or minimize heat stress, although it is not clear what properties do so. Here, we tested the possibility that black-furred individuals simply have shorter or thinner hair fibers, which would create a lighter （in terms of weight） coat or one that allows greater air flow for evaporative coo- ling. We examined museum specimens of eastern fox squirrels Sciurus niger, a species native to the United States and one that displays brown, grey or all-black pelage color, and used image analysis procedures to quantify hairs from the dorsal surface and tail. From examination of 43 specimens （19 brown, 9 black and 15 grey）, and 1,720 hairs, we found no significant difference in hair lengths across color morphs, but significant differences in hair fiber widths. Black squirrels had thinner body hairs than other forms （7% thinner）, but thicker tail hairs （9% thicker） than the others. Given that the dorsal surface would be directly exposed to solar radiation, we interpret this to be an adaptation to prevent heat stress during the day. The thicker tail hairs may be an adapta- tion for nighttime thermoregulation, since squirrels sleep with their tails wrapped around their bodies. These results add to a growing literature body of the functional significance of mammalian pelage [Current Zoology 57 （6）： 731-736, 2011].

关键词： Polymorphism Melanism Fox squirrels Sciurus niger Heat stress Hair morphology

regulation of protein degradation pathways by amino acids and insulin in skeletal muscle of neonatal pigs

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Journal of Animal Science and Biotechnology 2014年第3期5卷 299-309页

作者： Agus Suryawan Teresa A davis United States Department of Agriculture/Agricultural research Service Children's Nutrition research Center Department of PediatricsBaylor College of Medicine

Background： The rapid gain in lean mass in neonates requires greater rates of protein synthesis than degradation. We previously delineated the molecular mechanisms by which insulin and amino acids, especially leucine, modulate skeletal muscle protein synthesis and how this changes with development. In the current study, we identified mechanisms involved in protein degradation regulation. In experiment 1,6- and 26-d-old pigs were studied during 1） euinsulinemic-euglycemic-euaminoacidemic, 2） euinsulinemic-euglycemiohyperaminoacidemic, and 3） hyperinsulinemic-euglycemic-euaminoacidemic clamps for 2 h. In experiment 2, 5-d-old pigs were studied during 1） euinsulinemic-euglycemic-euaminoacidemic-euleucinemic, 2） euinsulinemic-euglycemic-hypoaminoacidemic- hyperleucinemic, and 3） euinsulinemic-euglycemic-euaminoacidemic-hyperleucinemic clamps for 24 h. We determined in muscle indices of ubiquitin-proteasome, i.e., atrogin-1 （MAFbx） and muscle rING-finger protein-1 （MurF1） and autophagy-lysosome systems, i.e., unc51-1ike kinase 1 （UKL1）, microtubule-associated protein light chain 3 （LC3）, and lysosomal-associated membrane protein 2 （Lamp-2）. For comparison, we measured ribosomal protein 56 （rpS6） and eukaryotic initiation factor 4E （elF4E） activation, components of translation initiation. results： Abundance of atrogin-1, but not MurF1, was greater in 26- than 6-d-old pigs and was not affected by insulin, amino acids, or leucine. Abundance of ULK1 and LC3 was higher in younger pigs and not affected by treatment. The LC3-11/LC3-1 ratio was reduced and ULK1 phosphorylation increased by insulin, amino acids, and leucine. These responses were more profound in younger pigs. Abundance of Lamp-2 was not affected by treatment or development. Abundance of elF4E, but not rpS6, was higher in 6- than 26-d-old-pigs but unaffected by treatment. Phosphorylation of elF4E was not affected by treatment, however, insulin, amino acids, and leucine stimulated rpS6 phosphorylation, and the resp

关键词： Amino acids Autophagy Insulin Leucine Muscle Neonate Protein degradation Protein synthesis,Swine Ubiquitin

Vaccine-associated myocarditis:a case report and summary of the literature

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World Journal of Emergency Medicine 2022年第6期13卷 485-487页

作者： Joshua davis Lauren Jennings University of Kansas School of Medicine Wichita 67214USA Vituity Wichita 67214USA American red Cross in Hazelwood Missouri 63042USA

Dear editor,Myocarditis is a known complication of vaccines for COVID-19,particularly mrNA *** it is rare,the exact incidence of vaccine-associated myocarditis is *** of personal choice in vaccination decisions often cite the risk of myocarditis as a reason one might choose not to receive the COVID-19 ***,we describe a case of focal myocarditis associated with the Pfizer-BioNTech COVID-19 vaccine and review the literature on the incidence and risk of COVID-19 vaccine-associated myocarditis.

关键词： myocarditis vaccine Pfizer

Lipid lowering in patients 75 years and older

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World Journal of Cardiology 2021年第10期13卷 526-532页

作者： Umidakhon Makhmudova P Christian Schulze Harry r davis Oliver Weingartner Klinik fur Innere Medizin I Universitatsklinikum JenaJena 07747Germany Synergy Partners rD Solutions Synergy Partners RD SolutionsGaithersburgMD 20850United States

More than twenty years ago,knowledge about the importance of cholesterol absorption and the potential therapeutic effect of its inhibition led to the discovery and clinical application of the first and only cholesterol absorption inhibitor to date–*** then,ezetimibe has become a well-recognized player in lipid-lowering *** findings of IMPrOVE-IT and EWTOPIA 75 imply that elderly patients over the age of 75 years in particular benefit from *** review summarizes the evidence,discusses the possible underlying pathophysiological mechanisms and calls for a change in future dyslipidemia guidelines.

关键词： Cholesterol Cholesterol absorption Cholesterol synthesis Ezetimibe Elderly

Comparison of the VO_(2)Master Pro and Cosmed K5 During Walking,Jogging,and running

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Journal of Science in Sport and Exercise 2022年第2期4卷 119-127页

作者： Alex Toulouse Dustin Joubert Gary Oden Patrick r.davis Department of Kinesiology Sam Houston State UniversityHuntsvilleTXUSA Department of Kinesiology and Health Science Stephen F.Austin UniversityNacogdochesTXUSA

Aim Portable devices that accurately detect the composition of expired gases and changes in VO_(2)open new possibilities in research methodology and *** The purpose of this study was to compare the oxygen consumption(VO_(2))measurements of the VO_(2)Master Pro(VM)to the Cosmed K5(K5)during walking,jogging,and running in field and lab *** Twelve proficient runners,with a current 10 k pace of≥11.29 km/h,performed 3 matched intervals at 3 different speeds(4.82,8.05,11.29 km/h)on a treadmill and on an outdoor *** airflow test was also performed on both devices by pumping air through the devices using a 3 L syringe timed to a metronome at 15,25,and 35 beats/*** The VM did not report walking data for most *** treadmill running,there were significant differences in VO_(2)(47.86±3.94 vs.29.56±4.15 mL/kg/min),ventilation(V_(e))(71 vs.57 mL/min),and tidal volume(TV)(1.89 vs.1.56 L)between the K5 and VM respectively(Pr analysis also showed significant differences between devices in VO_(2),V_(e),and TV(Prflow test showed significant differences between the devices in V_(e)and TV(Presults suggest that there are significant discrepancies between the K5 and the VM,likely due to differ-ences in TV measurement.

关键词： Oxygen consumption Energy expenditure Metabolic cart Comparison