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3eciphering the protein-DNA code of bacteria Ninged helix-turn-helix transcription factors

Frontiers of Electrical and Electronic Engineering in China 2018年第1期6卷 68-84页

作者： Adam P. j.yce j.mes j. Havranek Program in Developmental Regenerative and Stem Cell Biology Washington University in St. Louis St. Louis MO 63110 USA Department of Biochemistry and Molecular Biophysics Washington University in St. Louis St. Louis MO 63110 USA

Background： Sequence-specific binding by transcription factors （TFs） plays a significant role in the selection and regulation of target genes. At the protein：DNA interface, amino acid side-chains construct a diverse physicochemical network of specific and non-specific interactions, and seemingly subtle changes in amino acid identity at certain positions may dramatically impact TF：DNA binding. Variation of these specificity-determining residues （SDRs） is a maj.r mechanism of functional divergence between TFs with strong structural or sequence homology. Methods： In this study, we employed a combination of high-throughput specificity profiling by SELEX and Spec-seq, structural modeling, and evolutionary analysis to probe the binding preferences of winged helix-turn-helix TFs belonging to the OmpR sub-family in Escherichia coil Results： We found that E. coli OmpR paralogs recognize tandem, variably spaced repeats composed of＂GT-A＂ or ＂GCT＂-containing half-sites. Some divergent sequence preferences observed within the ＂GT-A＂ mode correlate with amino acid similarity; conversely, ＂GCT＂-based motifs were observed for a subset of paralogs with low sequence homology. Direct specificity profiling of a subset of OmpR homologues （CpxR, RstA, and OmpR） as well as predicted ＂SDR-swap＂ variants revealed that individual SDRs may impact sequence preferences locally through direct contact with DNA bases or distally via the DNA backbone. Conclusions： Overall, our work provides evidence for a common structural code for sequence-specific wHTH：DNA interactions, and demonstrates that surprisingly modest residue changes can enable recognition of highly divergent sequence motifs. Further examination of SDR predictions will likely reveal additional mechanisms controlling the evolutionary divergence of this important class of transcriptional regulators.

关键词： transcription factor SELEX winged helix-turn-helix specificity detenlainants two-component signaling

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Synthesis and characterization of novel star-shaped pyridine cored compounds with alternating carbazole and triphenylamine moieties

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Chinese Chemical Letters 2008年第6期19卷 647-650页

作者： j. Bing Yuan Zhi Guo Zhang louis Man Leung Ke Li Zhang College of Chemistry and Molecular Sciences Wuhan University Wuhan 430072 China College of Chemical and Environmental Engineering Hubei University of Technology Wuhan 430068 China Department of Chemistry Hong Kong Baptist University Hongkong China

Amorphous 2,4,6-trissubstituted pyridines containing three peripheral carbazole or two triphenylamine and one carbazole moieties, respectively, have been synthesized and characterized. The properties of the compounds are investigated by UV-vis absorption, photoluminescence spectroscopy, thermal analysis as well as cyclic voltammetry. The results show that the compounds have high thermal stability, emit blue light. Also, the compounds possess the HOMO and LUMO energy levels comparable to those of NPB. The effects of different substituents on the electronic properties of the materials have been discussed.

关键词： Star-shaped Carbazole Tdphenylamine Pyridine

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Evaluating and quantifying the effect of various spruce budworm intervention strategies on forest carbon dynamics in Atlantic Canada

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Forest Ecosystems 2022年第4期9卷 547-557页

作者： Zelin Liu Changhui Peng David AMacLean louis De Grandpre j.an-Noel Candau Daniel Kneeshaw School of Geographic Sciences Hunan Normal UniversityChangsha410081China Department of Biological Sciences University of Qu�ebec at MontrealMontrealQC H3C 3P8Canada Faculty of Forestry and Environmental Management University of New BrunswickFrederictonNB E3B 5A3Canada Laurentian Forestry Centre Canadian Forest ServiceNatural Resources CanadaQC G1V 4C7Canada Great Lake Forestry Centre Canadian Forest ServiceNatural Resources CanadaON P6A 2E5Canada

Spruce budworm (SBW) outbreaks are one of the most devastating natural disturbances in spruce-balsam fir forests of eastern North America. Both early intervention strategy (EIS) and foliage protection strategy (FP) are being tested to limit forest losses, but the quantitative impact on forest carbon (C) dynamics is still unclear. In this study, we designed 19 separate scenarios of no intervention or varying success of EIS, FP, and their combination on SBW caused defoliation and mortality. We then used the TRIPLEX-Insect model to quantify their effects on forest C dynamics in the forests of the four provinces of Atlantic Canada. A scenario applying FP to 10%of the area with the greatest potential C losses of living biomass, protecting foliage in 10%of the forests is more realistic than higher proportion of FP given the high cost and large areas involved, resulted in reducing average cumulative net ecosystem productivity (NEP) from 2020 to 2039 by 56%–127%compared to a no outbreak *** results showed that FP would have to be applied everywhere to reduce tree mortality and increase NEP more than 8 years of successful EIS applied. However, if EIS can be successfully implemented for 12 years, it will maintain more forest C than FP applied everywhere during a moderate outbreak. We also found that the combination of EIS followed by FP in 10%of the areas disturbed by the SBW could maintain average cumulative NEP at similar levels to no defoliation in every province of Atlantic Canada. Black/red spruce forests younger than 60years old underwent the smallest changes in C dynamics whether using EIS, FP, or both. This highlights the importance of forest species, forest age, and their interactions on the effectiveness of a treatment during SBW outbreak. Overall, 31%–76%of the study area in Atlantic Canada could convert from a C sink to a source by 2039,if no protective measures are used under the worst-case scenarios, thus contributing to future climate warming.

关键词： Annual defoliation Natural disturbance Forest protection Net ecosystem productivity TRIPLEX-Insect Conifers

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Development of an Integrated Tool for Small-Scale Maize Farming in Uganda

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Agricultural Sciences 2020年第7期11卷 653-666页

作者： louis j. M. Obura Robert K. Kambugu Nicholas Kiggundu Hussein K. Balimunsi Samuel Kyamanywa Department of Agricultural and Biosystems Engineering Makerere University Kampala Uganda Department of Agricultural Engineering University of Juba Juba South Sudan Department of Agricultural Production Makerere University Kampala Uganda

About 62% of the maize produced in developing countries is cultivated manually owing to limited access to appropriate technology. Available technologies perform a single operation, necessitating farmers to buy multiple implements, which is expensive. In this study, an ox-drawn tool integrating a plough, planter and cultivator for small-scale maize farming was developed and its performance evaluated. Planting and cultivating units were designed and fabricated for assembly onto an existing standard ox-plough beam. The integrated tool was tested in the field to assess the effectiveness and efficiency of cultivation and planting of maize. Results showed that the planting unit had an average seed rate of 35.4 kg/ha with a seed damage of 4% and an effective field capacity of 0.15 ha/h at a field efficiency of 87.3%. The cultivating unit had an effective field capacity of 0.1 ha/h and a weeding efficiency of 86%. The efficiency, effectiveness and reliability for field operations are superior to manual operations currently used by farmers and are comparable to single-unit prototypes developed in other countries. This demonstrates the technical feasibility of integrating planting and cultivation units onto an existing mould board plough instead of buying multiple tools.

关键词： Integrated Tool Plough Cultivator Mechanization Smallholder Maize Farming

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Responses of ramie(Boehmeria nivea L.)to increasing rare earth element(REE)concentrations in a hydroponic system

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j.urnal of Rare Earths 2022年第5期40卷 840-846,I0006页

作者： Chang Liu Wenshen Liu Hermine Huot Yiming Yang Meina Guo j.an louis Morel Yetao Tang Rongliang Qiu School of Environmental Science and Engineering Sun Yat-sen UniversityGuangzhou 510275China Laboratoire Sols et Environnement INRAE-Universitéde Lorraine54505Vandceuvre-les-NancyFrance Guangdong Provincial Key Laboratory of Environmental Pollution Control and Remediation Technology Guangzhou 510275China Guangdong Provincial Engineering Research Center for Heavy Metal Contaminated Soil Remediation Sun Yat-sen UniversityGuangzhou 510275China

A number of studies have focused on the effects of rare earth elements(REEs) on crop plants,while little attention has been paid on how tolerant plant species respond to increasing mixed REE *** this study,ramie(Boehmeria nivea L.) was exposed to a series of REE concentrations prepared with equimolar mixtures of 16 REEs(i.e.0,1.6,8,16,80,160,400,800 μmol/L) in order to explore REE accumulation and fractionation characteristics in ramie and the responses of this plant to mixed *** show that ramie root and shoot biomasses are unaffected under lower REE concentrations(1.6-80 μmol/L),while the growth of ramie and the uptake of nutrients especially Ca and Mn are largely inhibited under higher REE concentrations(160-800 μmol/L).The P and Mo concentrations in the roots increase with the increasing REE concentrations in the solution,suggestive of an involvement of P and Mo in dealing with the high concentrations of REEs in this *** preferential uptake of Ce and heavy REEs(HREEs) and the preferential transport of HREEs within the plant lead to a positive Ce anomaly and a HREE enrichment in ramie *** study suggests that ramie could be a good candidate for the phyto re mediation of heavily REE-contaminated soils(e.g.,REE mine tailings in southern China).Our results also shed light on points of taking into account phytoremediation management strategies of REEcontaminated soils(e.g.,P and Mo fertilization).

关键词： Phytoremediation Ramie Rare earth elements Fractionation Molybdenum Phosphorus

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Application of established pathophysiologic processes brings greater clarity to diagnosis and treatment of hyponatremia

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World j.urnal of Nephrology 2017年第2期6卷 59-71页

作者： j.hn K Maesaka louis j.Imbriano Nobuyuki Miyawaki Department of Medicine and Division of Nephrology and Hypertension Winthrop-University Hospital

Hyponatremia, serum sodium 〈 135 mEq/L, is themost common electrolyte abnormality and is in a state of flux. Hyponatremic patients are symptomatic and should be treated but our inability to consistently determine the causes of hyponatremia has hampered the delivery of appropriate therapy. This is especially applicable to differentiating syndrome of inappropriate antidiuresis （SIAD） from cerebral salt wasting （CSW） or more appropriately, renal salt wasting （RSW）, because of divergent therapeutic goals, to water-restrict in SIAD and administer salt and water in RSW. Differentiating SIAD from RSW is extremely diffcult because of identical clinical parameters that defne both syndromes and the mindset that CSW occurs rarely. It is thus insuffcient to make the diagnosis of SIAD simply because it meets the defned characteristics. We review the pathophysiology of SIAD and RSW, the evolution of an algorithm that is based on determinations of fractional excretion of urate and distinctive responses to saline infusions to differentiate SIAD from RSW. This algorithm also simplifes the diagnosis of hyponatremic patients due to Addison’s disease, reset osmostat and prerenal states. It is a common perception that we cannot accurately assess the volume status of a patient by clinical criteria. Our algorithm eliminates the need to determine the volume status with the realization that too many factors affect plasma renin, aldosterone, atrial/brain natriuretic peptide or urine sodium concentration to be useful. Reports and increasing recognition of RSW occurring in patients without evidence of cerebral disease should thus elicit the need to consider RSW in a broader group of patients and to question any diagnosis of SIAD. Based on the accumulation of supporting data, we make the clinically important proposal to change CSW to RSW, to eliminate reset osmostat as type C SIAD and stress the need for a new defnition of SIAD.

关键词： Hyponatremia Cerebral-renal salt wasting Fractional excretion of urate

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Use of the reported Edmonton frail scale in the assessment of patients for transcatheter aortic valve replacement： a possible selection tool in very high-risk patients？

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j.urnal of Geriatric Cardiology 2018年第6期15卷 463-466页

作者： louis Koizia Sarosh Khan Angela Frame Ghada W Mikhail Sayan Sen Neil Ruparelia Geriatric Medicine St Mary's Hospital Praed Street London UK Department of Cardiology Western Sussex Hospitals NHS Foundation Trust West Sussex UK Department of Cardiology lmperial College Healthcare NHS Trust London UK

Transcatheter aortic valve replacement （TAVR） has revolutionised the treatment of patients with aortic stenosis （AS） over the last 15 *** is a well-established procedure for the treatment of patients considered high risk for open surgery. Results from the PARTNER （Placement of AoRTic traNscathetER） trial showed that inoperable patients randomly assigned to TAVR, had a 20% reduction in all-cause mortality, as well as hospitalisation, at one year compared to best medical management.

关键词： Edmonton frail scale Frailty Transcatheter aortic valve replacement

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Key genes and drug delivery systems to improve the efficiency of chemotherapy

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Cancer Drug Resistance 2021年第1期4卷 163-191页

作者： Zally Torres-Martinez Yamixa Delgado Yancy Ferrer-Acosta Ivette j.Suarez-Arroyo Freisa M.j.aquin-Ovalle louis j.Delinois Kai Griebenow Chemistry Department University of Puerto Rico-Rio Piedras campusSan JuanPR 00936USA Biochemistry&Pharmacology Department San Juan Bautista School of MedicineCaguasPR 00726USA Neuroscience Department Universidad Central del CaribeBayamonPR 00956USA Biochemistry Department Universidad Central del CaribeBayamonPR 00956USA

Cancer cells can develop resistance to anticancer drugs,thereby becoming tolerant to treatment through different *** biological mechanisms leading to the generation of anticancer treatment resistance include alterations in transmembrane proteins,DNA damage and repair mechanisms,alterations in target molecules,and genetic responses,among *** most common anti-cancer drugs reported to develop resistance to cancer cells include cisplatin,doxorubicin,paclitaxel,and *** anticancer drugs have different mechanisms of action,and specific cancer types can be affected by different *** development of drug resistance is a cellular response which uses differential gene expression,to enable adaptation and survival of the cell to diverse threatening environmental *** this review,we briefly look at the key regulatory genes,their expression,as well as the responses and regulation of cancer cells when exposed to anticancer drugs,along with the incorporation of alternative nanocarriers as treatments to overcome anticancer drug resistance.

关键词： Cancer resistance drug delivery systems resistance genes

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Voltage-gated K^+channels promote BT-474 breast cancer cell migration

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Chinese j.urnal of Cancer Research 2018年第6期30卷 613-622页

作者： louis WC Chow Ka-Shun Cheng Kar-Lok Wong Yuk-Man Leung State Key Laboratory of Quality Research in Chinese Medicines Macao University of Science and TechnologyTaipaMacao 999078China UNIMED Medical Institute Hong Kong 999077China Organisation for Oncology and Translational Research Hong Kong 999077China Department of Anesthesiology China Medical University HospitalTaiehung 40447TaiwanChina Department of Anesthesiology the Qingdao University Yuhuangding HospitalYantai 264000China Department of Physiology China Medical UniversityTaichung 40402TaiwanChina

Obj.ctive: A variety of ion channels have been implicated in breast cancer proliferation and *** K+(Kv) channels not only cause repolarization in excitable cells,but are also involved in multiple cellular functions in non-excitable *** this study we investigated the role of Kv channels in migration of BT474 breast cancer ***: Transwell technique was used to separate migratory cells from non-migratory ones and these two groups of cells were subj.ct to electrophysiological examinations and microfluorimetric measurements for cytosolic *** migration was examined in the absence or presence of Kv channel ***: When compared with non-migratory cells,migratory cells had much higher Kv current densities,but rather unexpectedly,more depolarized membrane potential and reduced *** transcriptasepolymerase chain reaction(RT-PCR) analysis revealed the presence of Kv1.1,Kv1.3,Kv1.5,Kv2.1,Kv3.3,Kv3.4 and Kv4.3 *** migration was markedly inhibited by tetraethylammonium(TEA),a delayed rectifier Kv channel blocker,but not by 4-aminopyridine,an A-type Kv channel ***: Taken together,our results show that increased Kv channel expression played a role in BT474 cell migration,and Kv channels could be considered as biomarkers or potential therapeutic targets for breast cancer *** mechanism(s) by which Kv channels enhanced migration appeared unrelated to membrane hyperpolarization and Cainflux.

关键词： Breast cancer Kv channels migration biomarkers

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Review:Natural Polymer Electrolytes for Lithium Ion Batteries

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j.urnal of Harbin Institute of Technology(New Series) 2018年第1期25卷 1-17页

作者： Xuewei Fu Yu Wang louis Scudiero Weihong Zhong Department of Mechanical and Materials Engineering Washington State University Department of Chemistry Washington State University

Polymer electrolytes are attractive materials towards achieving safe,flexible and high-performance energy storage devices( ESDs) such as lithium ion batteries( LIBs). Conventional polymer electrolytes are confronted with big challenges to achieve high ionic conductivity,good mechanical properties,excellent biocompatibility and environmental friendliness. In this context,natural polymeric materials have appealing merits of multi-functionality,ease of accessibility,good mechanical strength,etc. making them promising candidates to substitute conventional polymer electrolytes. Recently,the rational design and fabrication of advanced natural bio-based polymer electrolytes have made important progresses. In this review, we summarize recent developments in terms of polymer electrolytes using natural polymers for several application purposes. This review also involves the merits and demerits of the different natural polymers that have been investigated thus far. The insights on state-of-the-art for natural polymer electrolytes and possible solutions for further improvement of them are discussed as well in this review.

关键词： polymer electrolytes natural polymer electrolytes lithium ion batteries

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