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journal of Environmental Sciences 2014年第4期26卷 801-809页

作者： Mengnjo j. Wirmvem Takeshi Ohba Wilson Y. Fantong samuel N. Ayonghe jonathan N. Hogarh justice Y. Suila Asobo Nkengmatia E. Asaah Seigo Ooki Gregory Tanyileke joseph V. Hell Department of Chemistry School of Science Tokai University Hiratsuka 259-1211 Japan Institute of Geological and Mining Research Yaounde Cameroon Department of Environmental Science Faculty of Science University of Buea Buea Cameroon Department of Environmental Science Kwame Nkrumah University of Science & Technology Kumasi Ghana G.B.H.S. Atiela Nkwen Bamenda Cameroon Department of Earth and Planetary Sciences Tokyo Institute of Technology Tokyo 152-8551 Japan

Rainwater characteristics can reveal emissions from various anthropogenic and natural sources into the atmosphere. The physico-chemical characteristics of 44 monthly rainfall events （collected between january and December 2012） from 4 weather stations （Bamenda, Ndop plain, Ndawara and Kumbo） in the Bamenda Highlands （BH） were investigated. The purpose was to determine the sources of chemical species, their seasonal inputs and suitability of the rainwater for drinking. The mean pH of 5 indicated the slightly acidic nature of the rainwater. Average total dissolved solids （TDS） were low （6.7 mg/L）, characteristic of unpolluted atmospheric moisture/air. Major ion concentrations （mg/L） were low and in the order K＋〉 Ca2＋〉 Mg2~ 〉 Na＋ for cations and NO3 〉〉 HCO3 〉 SO] 〉 CI- 〉 PO3- 〉 F- for anions. The average rainwater in the area was mixed Ca-Mg-SO4-CI water type. The CI-/Na＋ ratio （1.04） was comparable to that of seawater （1.16）, an indication that N a＋ and CI originated mainly from marine （Atlantic Ocean） aerosols. High enrichments of Ca2＋, Mg2＋ and SO2- to Na＋ ratios relative to seawater ratios （constituting 44% of the total ions） demonstrated their terrigenous origin, mainly from Saharan and Sahelian arid dusts. The K＋/Na＋ ratio （2.24）, which was similar to tropical vegetation ash （2.38）, and NO3 was essentially from biomass burning. Light （〈 100 mm） pre-monsoon and post-monsoon convective rains were enriched in major ions than the heavy （〉 100 mm） monsoon rains, indicating a high contribution of major ions during the low convective showers. Despite the acidic nature, the TDS and major ion concentrations classified the rainwater as potable based on the WHO guidelines.

关键词： rainwater chemistry tropical atmosphere drinking-water Bamenda Highlands Cameroon

Ionic Species Affect the Self-Propulsion of Urease-Powered Micromotors

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Research 2020年第1期2020卷 349-362页

作者： Xavier Arque Xavier Andres Rafael Mestre Bernard Ciraulo jaime Ortega Arroyo Romain Quidant Tania Patino samuel Sanchez Institute for Bioengineering of Catalonia(IBEC) The Barcelona Institute of Science and Technology(BIST)Baldiri i Reixac 10-1208028 BarcelonaSpain Institute of Photonic Sciences(ICFO) The Barcelona Institute of Science and TechnologyCarl Friedrich Gauss 308860 CastelldefelsBarcelonaSpain InstitucióCatalana de Recerca i Estudis Avançats(ICREA) Pg.Lluís Companys 2308010 BarcelonaSpain Chemistry Department University of RomeTor VergataVia della Ricerca Scientifica00133 RomeItaly

Enzyme-powered motors self-propel through the catalysis of in situ bioavailable fuels,which makes them excellent candidates for biomedical ***,fundamental issues like their motion in biological fluids and the understanding of the propulsion mechanism are critical aspects to be tackled before a future application in ***,we investigated the physicochemical effects of ionic species on the self-propulsion of urease-powered *** showed that the presence of PBS,NaOH,NaCl,and HEPES reduced self-propulsion of urease-powered micromotors pointing towards iondependent mechanisms of *** studied the 3D motion of urease micromotors using digital holographic microscopy to rule out any motor-surface interaction as the cause of motion decay when salts are present in the *** order to protect and minimize the negative effect of ionic species on micromotors’performance,we coated the motors with methoxypolyethylene glycol amine(mPEG)showing higher speed compared to noncoated motors at intermediate ionic *** results provide new insights into the mechanism of urease-powered micromotors,study the effect of ionic media,and contribute with potential solutions to mitigate the reduction of mobility of enzyme-powered micromotors.

关键词： holographic salts catalysis

Effect of High Temperature Treatment on Aqueous Corrosion of Low-Carbon Steel by Electrochemical Impedance Spectroscopy

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Materials Sciences and Applications 2011年第2期2卷 81-86页

作者： samuel j. Gana Nosa O. Egiebor Ramble Ankumah 不详

The corrosion behavior of 1020C carbon steel samples that had been subjected to oxidizing heat treatment at 550°C and 675°C were studied in sodium chloride electrolytes using a 3-electrode electrochemical impedance spectroscopy. Experimental data were used to evaluate the corrosion behavior of the samples while optical microscopy was employed to investigate the surface characteristics of the samples before and after aqueous corrosion. The results showed that while the sample treated at 550°C revealed an increasing corrosion rate with time, the sample treated at 675°C indicated a higher initial corrosion rate, but the rate declined gradually over the 4-day experimental period. Optical microscopy revealed significant formation of surface corrosion products on both heat treated samples, but the complex plane diagrams indicated significant capacitive behavior for the heat treated samples relative to the untreated samples.

关键词： Impedance Carbon Steel Corrosion Nyquist Diagrams Photomicrographs

The combined role of MRI prostate and prostate health index in improving detection of significant prostate cancer in a screening population of Chinese men

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Asian journal of Andrology 2023年第6期25卷 674-679页

作者： Peter KF Chiu Thomas YT Lam Chi-Fai Ng jeremy YC Teoh Carmen CM Cho Hiu-Yee Hung Cindy Hong Monique j Roobol Winnie CW Chu samuel YS Wong joseph jY Sung SH Ho Urology Centre Department of SurgeryThe Chinese University of Hong KongHong Kong SARChina The jockey Club School of Public Health and Primary Care The Chinese University of Hong KongHong Kong SARChina Department of Imaging and Interventional Radiology The Chinese University of Hong KongHong Kong SARChina Erasmus MC Cancer Institute Erasmus Medical UniversityRotterdam 3015The Netherlands Lee Kong Chian School of Medicine Nanyang Technological UniversitySingapore 308232Singapore

Using prostate-specific antigen(PSA)for prostate cancer(PCa)screening led to overinvestigation and overdiagnosis of indolent *** aimed to investigate the value of prostate health index(PHI)and magnetic resonance imaging(MRI)prostate in an Asian PCa screening *** aged 50–75 years were prospectively recruited from a community-based PSA screening *** with PSA 4.0–10.0 ng ml^(−1) had PHI result *** prostate was offered to men with PSA 4.0–50.0 ng ml−1.A systematic prostate biopsy was offered to men with PSA 4.0–9.9 ng ml^(−1) and PHI≥35,or PSA 10.0–50.0 ng ml^(−1).Additional targeted prostate biopsy was offered if they had PI-RADS score≥*** significant PCa(csPCa)was defined as the International Society of Urological Pathology(ISUP)grade group(GG)≥2 or ISUP GG 1 with involvement of≥30%of total systematic *** total,12.8%(196/1536)men had PSA≥4.0 ng ml^(−1).Among 194 men with PSA 4.0–50.0 ng ml^(−1),187(96.4%)received MRI *** them,28.3%(53/187)had PI-RADS≥3 ***,7.0%(107/1536)men were indicated for biopsy and 94.4%(101/107)men received *** the men received biopsy,PCa,ISUP GG≥2 PCa,and csPCa was diagnosed in 42(41.6%),24(23.8%),and 34(33.7%)men,*** with PSA/PHI pathway in men with PSA 4.0–50.0 ng ml^(−1),additional MRI increased diagnoses of PCa,ISUP GG≥2 PCa,and csPCa by 21.2%(from 33 to 40),22.2%(from 18 to 22),and 18.5%(from 27 to 32),*** benefit of additional MRI was only observed in PSA 4.0–10.0 ng ml^(−1),and the number of MRI needed to diagnose one additional ISUP GG≥2 PCa was 20 in PHI≥35 and 94 in PHI<*** them,45.4%(89/196)men with PSA≥4.0 ng ml^(−1) avoided unnecessary biopsy with the use of PHI and MRI.A screening algorithm with PSA,PHI,and MRI could effectively diagnose csPCa while reducing unnecessary *** benefit of MRI prostate was mainly observed in PSA 4.0–9.9 ng ml^(−1) and PHI≥35 *** was an important risk stratification step for PCa

关键词： magnetic resonance imaging prostate prostate cancer prostate health index prostate-specific antigen screening

Field evidences showing rapid frontal degeneration of the Kangriz glacier,western Himalayas,jammu&Kashmir

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journal of Mountain Science 2018年第6期15卷 1199-1208页

作者： GARG Siddhi SHUKLA Aparna MEHTA Manish KUMAR Vinit samuel Shruti Anna BARTARYA S.K. SHUKLA Uma Kant Wadia Institute o/Himalayan Geology 33 GMS Road Dehradun 248001 India Department of Geology Banaras Hindu University Varanasi 221005 India

Life cycle of glaciers in the Himalayan region has notably changed due to the climatic variability since last few decades. Glaciers across the world and specially the Himalayan glaciers have shown large scale degeneration in the last few decades. Himalayan glaciers serve as an important fresh water resource for the downstream communities, who are dependent on this water for domestic and other purposes. Therefore, glacier shrinkage and the associated hydrological changes pose a significant problem for regional-scale water budgets and resource management. These issues necessitate the regular and rigorous monitoring of the wastage pattern of the Himalayan glaciers in field and using satellite remote sensing data. In this work, we report rapid and enhanced degeneration of the frontal part of the Kangriz glacier, jammu and Kashmir(j & K), in terms of surface melting, debris cover, snout characteristics and meltwater discharge. Ablation data acquired during 2016-2017 shows the average lowering of the frontal part of the glacier to be ~148 ± 34 cm, one-third of which was found to have occurred within a 13 day time period in September, 2017. Also, the quantum of ice melt was found to be inversely influenced(r =-0.84) by the debris thickness. 15 day meltwater discharge measurement revealed its strong relationship with snout disintegration pattern, evidenced twice during the said time period. Volume of water discharged from the glacier was estimated to be 7.91×10~6 m^3 for the measurement duration. Also, mean daily discharge estimated for the 15 days interval showed good positive correction(r = 0.78) with temperature indicating the direct dependency of the former on land surface temperature conditions of the region. Besides the lowering and discharge observations, the frequent ice-block break-offs at the glacier snout further enhance its overall drastic degeneration. The study suggests that, being the largest glacier in the Suru basin, the Kangriz glacier needs to be continuo

关键词： Glacier shrinkage Western Himalayas Surface lowering Degeneration Meltwater discharge

Water Resources, Infrastructure Restoration, and Protection of the Upper Mississippi River Basin

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Open journal of Soil Science 2021年第1期11卷 13-38页

作者： Kenneth R. Olson samuel j. Indorante Gerald A. Miller Professor Emeritus of Soil Science in the Department of Natural Resources and Environmental Sciences College of Agricultural Consumer and Environmental Sciences University of Illinois Urbana Illinois USA Soil Science at Southern Illinois University Carbondale Illinois USA Professor Emeritus of Soil Science in the Department of Agronomy College of Agriculture and Life Sciences at Iowa State University Ames Iowa USA

The Upper Mississippi River flows approximately 2000 km from Lake Itasca, Minnesota to Cairo, Illinois where it is confluences with the Ohio River to form the Lower Mississippi River. North of the confluence, numerous snags, sand bars, rapids, and other obstructions made the Upper Mississippi River travel difficult. This paper highlights how the geological and landscape resources of the Upper Mississippi River and tributary watershed were responsible for the successful economic development of this historically rich region of North America. Environmental challenges include an attempt to keep invasive species such as the Asian carp out of the rivers and lakes north of the Twin Cities. In an attempt to protect the Mississippi River resource, Environmental and Conservation groups have opposed continued navigation through Minneapolis and St. Paul and the planned Upper Mississippi River navigation infrastructure restoration by the United States Corps of Engineers including the upper and lower St. Anthony locks and dams. These Environmental, Conservation and Save the River groups are attempting to mitigate the historic highest and best use of the Mississippi River and adjacent watershed, navigation, and economic development, by having the urban river restored to the natural state.

关键词： Falls of St. Anthony Locks Dams Minneapolis St. Paul Navigation Water Pollution

The influence of mobility among high-risk populations on HIV transmission in Western Kenya

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Infectious Disease Modelling 2018年第1期3卷 97-106页

作者： Anna Bershteyn Kennedy K.Mutai Adam N.Akullian Daniel j.Klein Britta L.jewell samuel M.Mwalili Institute for Disease Modeling 3150139th Ave.SEBellevueWA 98005USA National Aids Control Council P.O.Box 61307-00200Argwings Kodhek RdNairobiKenya Department of Medicine University of California and San FranciscoZuckerberg San Francisco General Hospital1001 Potrero AvenueSan FranciscoCA 94110USA Centers for Disease Control and Prevention PO Box 606Village MarketNairobi00621Kenya

Western Kenya suffers a highly endemic and also very heterogeneous epidemic of human immunodeficiency virus(HIV).Although female sex workers(FSW)and their male clients are known to be at high risk for HIV,HIV prevalence across regions inWestern Kenya is not strongly correlated with the fraction of women engaged in commercial *** agentbased network model of HIV transmission,geographically stratified at the county level,was fit to the HIV epidemic,scale-up of interventions,and populations of FSW in Western Kenya under two assumptions about the potential mobility of FSW *** the first,all clients were assumed to be resident in the same geographies as their interactions with *** the second,some clients were considered non-resident and engaged only in interactions with FSW,but not in longer-term non-FSW partnerships in these *** both assumptions,the model successfully reconciled disparate geographic patterns of FSW and HIV *** patterns in the model suggest a greater role for FSW in local transmission when clients were resident to the counties,with 30.0%of local HIV transmissions attributable to current and former FSW and clients,compared to 21.9%when mobility of clients was ***,the overall epidemic drivers remained similar,with risky behavior in the general population dominating transmission in highprevalence *** modeling suggests that co-location of high-risk populations and generalized epidemics can further amplify the spread of HIV,but that large numbers of formal FSW and clients are not required to observe or mechanistically explain high HIV prevalence in the general population.

关键词： prevalence client stratified

Hippocampal and visuospatial learning defects in mice with a deletion of frizzled 9, a gene in the Williams syndrome deletion interval

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Hippocampal and visuospatial learning defects in mice with a...

Overview of ytterbium based transparent ceramics for diode pumped high energy solid-state lasers

中国神经科学学会第六届学术会议暨学会成立十周年庆祝大会

作者：赵春杰 samuel j. Pleasure 东南大学遗传研究中心 UCSF San Francisco 94143

＜正＞Wnt signaling regulates hippocampal development but little is known about the functions of specific Wnt receptors in this structure. Frizzled 9 is selectively expressed in the hippocampus and is one of about 20 genes typically deleted in Williams syndrome. Since Williams syndrome is associated with severe visuospatial processing defects, we generated a targeted null allele for frizzled 9 to examine its role in hippocampal development. Frizzled 9-null mice had generally normal gross anatomical hippocampal organization but showed large increases in apoptotic cell death in the developing dentate gyrus. This increase in programmed cell death commenced with the onset of dentate gyrus development and persisted into the first postnatal week of life. There was also a perhaps compensatory increase in the number of dividing precursors in the dentate gyrus, which may have been a compensatory response to the increased cell death. These changes in the mutants resulted in a moderate decrease in the number of adult dentate granule cells in null mice and. an increase in the number of hilar mossy cells.

关键词： hippocampus wnt Williams syndrome

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High Power Laser Science and Engineering 2018年第4期6卷 109-118页

作者： samuel Paul David Venkatesan jambunathan Antonio Lucianetti Tomas Mocek HiLASE Centre Institute of Physics of the Czech Academy of SciencesZa Radnicí 8285

Development of high energy laser sources with nanosecond pulses at several hertz values for repetition rate has been very attractive in recent years due to their great potential for practical applications. With the recent advancement in fabricating large size laser quality transparent ceramics, diode pumped solid-state laser generating pulse energy of 100 j at 10 Hz has been recently realized at HiLASE center using Yb:YAG ceramic with Cr:YAG cladding. This review discusses Yb based high energy lasers, specific laser geometries for efficient thermal management and the role of transparent ceramics in such diode pumped high-energy-class solid-state lasers around the world.

关键词： diode pumped solid-state lasers high energy lasers laser materials transparent ceramics