检索结果-南通市图书馆

Assessing the effects of surface-bound humic acid on the phototoxicity of anatase and rutile TiO_2 nanoparticles in vitro

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Journal of Environmental Sciences 2016年第4期28卷 50-60页

作者： Xiaojia He Sabrieon Sanders Winfred G.Aker Yunfeng Lin Jessica douglas Huey-min Hwang Department of Biology Jackson State University Department of Biological Sciences Alcorn State University Environmental Science Ph.D.Program Jackson State University Department of Chemistry and Biochemistry Jackson State University School of Polymers and High Performance Materials The University of Southern Mississippi

In this study,the cytotoxicity of two different crystal phases of TiO2 nanoparticles,with surface modification by humic acid（HA）,to Escherichia coli,was *** physicochemical properties of TiO2 nanoparticles were thoroughly *** different initial concentrations,namely 50,100,and 200 ppm,of HA were used for synthesis of HA coated TiO2 nanoparticles（denoted as A/RHA50,A/RHA100,and A/RHA200,respectively）.Results indicate that rutile（LC50（concentration that causes 50%mortality compared the control group）=6.5）was more toxic than anatase（LC50=278.8）under simulated sunlight（SSL）irradiation,possibly due to an extremely narrow band *** is noted that HA coating increased the toxicity of anatase,but decreased that of ***,AHA50 and RHA50had the biggest differences compared to uncoated anatase and rutile with LC50of 201.9 and21.6,*** then investigated the formation of reactive oxygen species（ROS）by TiO2 nanoparticles in terms of hydroxyl radicals（OH）and superoxide anions（O2^-）.Data suggested that O2^- was the main ROS that accounted for the higher toxicity of rutile upon SSL *** also observed that HA coating decreased the generation of OH and O2^- on rutile,but increased O2^- formation on *** from TEM analysis also indicated that HA coated rutile tended to be attached to the surface of *** more than anatase.

关键词： TiO2nanoparticles Escherichia coli Humic acid Crystallinity Surface coating

Diphosphine-induced chiral propeller arrangement ofgold nanoclusters for singlet oxygen photogeneration

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Nano Research 2018年第11期11卷 5787-5798页

作者： Jiangwei Zhang Yang Zhou KaiZheng Hadi Abroshan douglas R. Kauffman Junliang Sun Gao Li State Key Laboratory of Catalysis Dalian Institute of Chemical Physics Chinese Academy of Sciences Dalian 116023 China University of Chinese Academy of Sciences Beijing 100049 China SUNCAT Center for Interface Science and Catalysis Department of Chemical Engineering Stanford University 443 Via Ortegc~ StanfordCalifornia 94305 USA National Energy Technology Laboratory (NETL) United States Department of Energy Pittsburgh Pennsylvania 15236 USA Beijing National Laboratory for Molecular Sciences State Key Laboratory of Rare Earth Materials Chemistry and Applications College ot Chemistry and Molecular Engineering Peking University Beijing 100871 China

In this study, 1,2-bis(diphenylphosphino)ethane (dppe) ligands are used to synthesize gold nanoclusters with an icosahedral Au-13 core. The nanoclusters are characterized and formulated as [Au-13(dppe)5Cl(2)]Cl-3 using synchrotron radiation X-ray diffraction, UV/Vis absorption spectroscopy, electrospray ionization mass spectrometry, and density functional theory (DFT) calculations. The bidentate feature of dppe ligands and the positions of coordinating surface gold atoms induce a helical arrangement that forms a propeller-like structure, which reduces the symmetry of the gold nanocluster to C-1. Therefore, dppe ligands perform as a directing agent to create chiral an ansa metallamacrocycle [Au-13(dppe)(5)Cl-2](3+) nanocluster, as confirmed by simulated electronic circular dichroism spectrum. The highest occupied molecular orbital (HOMO)-lowest unoccupied molecular orbital (LUMO) gap of the [Au-13(dppe)(5)Cl-2](3+) cluster is determined as approx. 1.9 eV, and further confirmed by ultraviolet photoemission spectroscopy analysis and DFT simulation. Furthermore, the photoactivity of [Au-13(dppe)(5)Cl-2](3+) is investigated, with the nanocluster shown to possess near-infrared photoluminescence properties, which can be employed for O-1(2) photogeneration. The quantum yield of O-1(2) photogeneration using the [Au-13(dppe)(5)Cl-2](3+) nanocluster is up to 0.71, which is considerably higher than those of anthracene (an organic dye), and Au-25 and Au-38 nanoclusters.

关键词： gold nanoclusters Au-13 chirality singlet oxygen synchrotron radiation X-ray diffraction (XRD)

Bayesian optimization with active learning of design constraints using an entropy-based approach

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

npj Computational Materials 2023年第1期9卷 1866-1879页

作者： Danial Khatamsaz Brent Vela Prashant Singh Duane D.Johnson douglas Allaire Raymundo Arróyave J.Mike Walker’66 Department of Mechanical Engineering Texas A&M UniversityCollege StationTX 77843USA Department of Materials Science and Engineering Texas A&M UniversityCollege StationTX 77843USA Ames Laboratory U.S.Department of EnergyIowa State UniversityAmesIA 50011USA Department of Materials Science&Engineering Iowa State UniversityAmesIA 50011USA Department of Industrial and Systems Engineering Texas A&M UniversityCollege StationTX 77843USA

The design of alloys for use in gas turbine engine blades is a complex task that involves balancing multiple objectives and *** alloys must be ductile at room temperature and retain their yield strength at high temperatures,as well as possess low density,high thermal conductivity,narrow solidification range,high solidus temperature,and a small linear thermal expansion *** Integrated Computational Materials Engineering(ICME)methods are not sufficient for exploring combinatorially-vast alloy design spaces,optimizing for multiple objectives,nor ensuring that multiple constraints are *** this work,we propose an approach for solving a constrained multi-objective materials design problem over a large composition space,specifically focusing on the Mo-Nb-Ti-V-W system as a representative Multi-Principal Element Alloy(MPEA)for potential use in next-generation gas turbine *** approach is able to learn and adapt to unknown constraints in the design space,making decisions about the best course of action at each stage of the *** a result,we identify 21 Pareto-optimal alloys that satisfy all *** proposed framework is significantly more efficient and faster than a brute force approach.

关键词： alloys solidification alloy

IMPROVING THE LINK BETWEEN THE LEED GREEN BUILDING LABEL AND A BUILDING’S ENERGY-RELATED ENVIRONMENTAL METRICS

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Green Building 2008年第2期3卷 85-105页

作者： G.Christopher Wedding douglas Crawford-Brown Cherokee Investment Services 111 East Hargett StreetSuite 300RaleighNorth CarolinaUSA 27601. Pell Frischmann 5 Manchester SquareLondonUK W1A 1AU

The US Green Building Council’s (USGBC) Leadership in Energy and Environmental Design (LEED) green buildingrating program has grown from a little known tool for market change to a label and brand relied upon by many ofthe largest players in real estate. It now serves as an indicator of sustainability and an instrument for environmentalmanagement. While LEED-certifi ed buildings tend to offer greater environmental benefi ts than their conventionalcounterparts, research and experience shows that the variation in and magnitude of these benefi ts varies, even amongbuildings of the same LEED certifi cation level. In light of growing concerns about “greenwashing” and the liabilityassociated with questionable environmental declarations, it is important to ensure that users of LEED and similarcertifi cation programs receive a set of benefi ts comparable to those expected. With a focus on energy-related issues, thisresearch (1) highlights evidence of the inconsistency between the expected and actual benefi ts of LEED buildings, (2)suggests revisions to LEED’s Energy & Atmosphere (EA) section to reduce the variation and magnitude in the energyrelatedenvironmental impacts from LEED buildings, (3) quantifi es this reduction in variation and magnitude ofimpacts using Monte Carlo analyses and probabilistic models created specifi cally for this research, (4) compares carbondioxide emissions from LEED buildings to the Architecture 2030 Challenge goals and (5) quantifi es the importanceof scoring LEED buildings on a per capita normalized basis. This research is a follow-up piece to the authors’ previouswork published in the Journal of Green Building (Wedding and Crawford-Brown 2007).

关键词： green building USGBC LEED Monte Carlo analysis greenwashing probabilistic modeling carbon offsets green power Architecture 2030 Challenge

AN ANALYSIS OF VARIATION IN THE ENERGY-RELATED ENVIRONMENTAL IMPACTS OF LEED CERTIFIED BUILDINGS

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Green Building 2007年第4期2卷 151-170页

作者： G.Christopher Wedding douglas Crawford-Brown Cherokee Investment Services USA Institute for the Environment University of North Carolina at Chapel HillUSA

The US Green Building Council’s(USGBC)LEED guidelines have become the dominant third-party certification program for“green”buildings in the *** that buildings use 37%of all energy and 68%of all electricity while contributing substantially to air emission,waste generation,and water consumption issues in the US,one of LEED’s purposes is to address the environmental impacts of energy use in *** research analyzes(1)how well the LEED guidelines measure these impacts and(2)which parameters create the most variation among these *** impacts here refer to emissions of carbon dioxide,nitrogen oxides,sulfur dioxide,mercury,and par-ticulate matter(PM10);solid waste;nuclear waste;and water *** data from the US Department of Energy,the National Renewable Energy Laboratory,the US EPA Energy Star program,and the USGBC,among others,models using Monte Carlo analysis were created to simulate the range of impacts of LEED-certified *** metrics and statistics were calculated to highlight the significance of variation in these *** re-search needs and implications of the results for LEED version 3.0 are also discussed.

关键词： LEED USGBC green building Monte Carlo analysis energy environmental impacts carbon dioxide particulate matter nitrogen oxides sulfur dioxides mercury nuclear waste solid waste water consumption

Hardware,Software,and Wetware Codesign Environment for Synthetic Biology

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

BioDesign Research 2022年第1期2022卷 136-150页

作者： Samuel M.D.Oliveira douglas Densmore Department of Electrical and Computer Engineering Boston UniversityMA 02215USA Biological Design Center Boston UniversityMA 02215USA

Synthetic biology is the process of forward engineering living *** systems can be used to produce biobased materials,agriculture,medicine,and *** approach to designing these systems is to employ techniques from the design of embedded *** techniques include abstraction,standards,modularity,automated design,and formal semantic models of ***,these elements form the foundation of“biodesign automation,”where software,robotics,and microfluidic devices combine to create exciting biological systems of the *** paper describes a“hardware,software,wetware”codesign vision where software tools can be made to act as“genetic compilers”that transform high-level specifications into engineered“genetic circuits”(wetware).This is followed by a process where automation equipment,welldefined experimental workflows,and microfluidic devices are explicitly designed to house,execute,and test these circuits(hardware).These systems can be used as either massively parallel experimental platforms or distributed bioremediation and biosensing ***,scheduling and control algorithms(software)manage these systems’actual execution and data analysis tasks.A distinguishing feature of this approach is how all three of these aspects(hardware,software,and wetware)may be derived from the same basic specification in parallel and generated to fulfill specific cost,performance,and structural requirements.

关键词： hardware Together execution

Helicobacter pylori recurrence after eradication in Latin America:Implications for gastric cancer prevention

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

World Journal of Gastrointestinal Oncology 2017年第4期9卷 184-193页

作者： Juan E Corral Robertino Mera Corey W Dye douglas R Morgan Division of Gastroenterology and Hepatology Mayo Clinic Division of Gastroenterology Hepatologyand NutritionVanderbilt University Department of Medicine University of Miami Miller School of Medicine

To estimate Helicobacter pylori (H. pylori) recurrence rate in Latin America, a region with a significant H. pylori prevalence and gastric cancer burden. METHODSPubMed, LILACS, SciELO, Cochrane databases and abstracts from relevant meetings were reviewed. Information collected included: Participants’ characteristics, recruitment strategy, diagnostic modality, treatment arms, follow-up and recurrence rates. Recurrence was calculated using 100-patients-year rates, and data were pooled using a random effects model. The I2 statistic assessed between study heterogeneity. Meta-regression analyses evaluated for effect modifying variables. RESULTSLiterature search yielded 163 articles. Twelve studies involving 4848 patients from 9 countries met inclusion criteria. Four hundred and thirty-two reinfections were recorded in 5487 person-years of follow-up. Pooled analysis showed a recurrence rate of 7.9 cases per 100 person-years (95%CI: 5.3-10.5). Meta-regression revealed that neither the antibiotic schema, a second antibiotic course, nor the diagnostic modality had an impact on the observed risk of recurrence. The recurrence rate in the first year after treatment, predominantly recrudescence, was 11.2 (6.1-16.4) per 100 patient years. Recurrence in subsequent years, was only 6.2 (3.8-8.7). CONCLUSIONH. pylori recurrence rates in Latin America are significant, and with geographic variability, yet are acceptable based upon the current literature for consideration of large scale intervention trials. Further research in Latin America is warranted to evaluate the efficacy, cost-effectiveness, and potential adverse outcomes of proposed eradication programs.

关键词： Gastric cancer Reinfection Hispanic Helicobacter pylori Latin America

Updates on the relation of weight excess and reproductive function in men： sleep apnea as a new area of interest

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Asian Journal of Andrology 2012年第1期14卷 77-81,176,177页

作者： Ahmad O Hammoud douglas T Carrell Mark Gibson C Matthew Peterson A Wayne Meikle Division of Reproductive Endocrinology and Infertility Department of Obstetrics and Gynecology University of Utah School of Medicine Salt Lake City UT 84108 USA Androiogy and IVF Laboratories Department of Surgery （Urology） and Physiology University of Utah School of Medicine Salt Lake City UT 84108 USA Endocrinology/ Diabetes Research Department of Medicine University of Utah School of Medicine Salt Lake City UT 84132 USA

Obesity has a negative effect on male reproductive function. It is associated with low testosterone levels and alteration in gonadotropin secretion. Male obesity has been linked to reduced male fertility. Data regarding the relation of obesity to sperm parameters are conflicting in terms of the nature and magnitude of the effect. New areas of interest are emerging that can help explain the variation in study results, such as genetic polymorphism and sleep apnea. Sleep disorders have been linked to altered testosterone production and hypogonadism in men. It was also correlated to erectile dysfunction. The relation of sleep disorders to male fertility and sperm parameters remains to be investigated. Men with hypogonadism and infertility should be screened for sleep apnea. Treatment of obesity and sleep apnea improves testosterone levels and erectile function.

关键词： infertility male infertility reproductive function sleep apnea weight excess

Morphological characterization, antioxidant capacity and diversity of Syzygium cumini trees from Sri Lanka

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Horticultural Plant Journal 2022年第1期8卷 53-67页

作者： Prasajith Kapila Dissanayake Wekumbure Gedara Chandima Wekumbura Alge Watage Wijeratne douglas Siril Abeywickrama Wijesundara Faculty of Agricultural Sciences Sabaragamuwa University of Sri LankaBelihuloya 70140Sri Lanka Department of Agronomy Throckmorton Plant Sciences CenterKansas State UniversityManhattanKS 66506USA National Institute of Fundamental Studies Kandy 20000Sri Lanka

Syzygium cumini(L.)Skeels(Madan)is widely distributed in South Asian countries,including Sri Lanka,where it was naturally *** were only few studies reported on *** for its values and other benefits in Sri *** study focuses on morphological characterization and the diversity of *** trees in seven locations of Sri *** were collected on different morphological ***,flower and fruit morphology showed significant differences among ***,trees from Batticaloa region showed different morphology,which would potentially open a different avenue for further study to trace different cultivars across the *** of the diversity index and multivariate analyses indicated high diversity in morphology and antioxidant capacity of *** variables such as leaf area,inter-nodal length,petiole length,anther length,filament length,fruit size and pericarp thickness could be suitable candidates to investigate the morphological variation of *** any *** capacity studies also showed significant differences among locations and *** hue angle was positively correlated to antioxidant *** of this study concluded that the wide distribution of *** trees throughout Sri Lanka in different geographical locations showed high diversity in leaf,flower and fruit morphology together with antioxidant capacity.

关键词： Syzygium cumini Morphological diversity Antioxidant capacity Sri Lanka