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Interactive influence of rainfall manipulation and livestock grazing on species diversity of the herbaceous layer community in a humid savannah in Kenya

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Plant Diversity 2019年第3期41卷 198-205页

作者： Joseph O.Ondier Daniel O.Okach john c.onyango Dennis O.Otieno Department of Botany Maseno University Private Bag Maseno Kenya Department of Biological Sciences Jaramogi Oginga Odinga University of Science and Technology P.O Box 210-40601 Bondo Kenya Department of Plant Ecology University of Bayreuth D-95440 Bayreuth Germany

changes in rainfall regime and grazing pressure affect vegetation composition and diversity with ecological implications for savannahs. The savannah in East Africa has experienced increased livestock grazing and rainfall variability but the impacts associated with those changes on the herbaceous layer have rarely been documented. We investigated the effect of livestock grazing, rainfall manipulation and their interaction on the composition and diversity of the herbaceous community in the savannah for two years in Lambwe, Kenya. Rainfall manipulation plots were set up for vegetation sampling;these plots received either 50% more or 50% less rainfall than control plots. Simpson’s diversity and Bergere Parker indices were used to determine diversity changes and dominance respectively. The frequency of species was used to compute their abundance and their life forms as determined from the literature. Grazing significantly increased species diversity through suppression of dominant species. Rainfall manipulation had no significant impact on plant diversity in fenced plots, but rainfall reduction significantly reduced diversity in grazed plots. In contrast, rainfall manipulation had no impact on dominance in either fenced or grazed plots. The interaction of grazing and rainfall manipulation is complex and will require additional survey campaigns to create a complete picture of the implications for savannah structure and composition.

关键词： Plant diversity Grazing Rainfall Moist savannah

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Novel Synthesis and characterization of cellulose Nanocrystals composites Fabricated from Rice Husks

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Advances in chemical Engineering and Science 2025年第1期15卷 1-16页

作者： Antonate Wanyonyi Godfrey Okumu Barasa john onyango Agumba Samwel onyango Okoth Edwin Atego Department of Physical Sciences Jaramogi Oginga Odinga University of Science and Technology Bondo Kenya

Nanotechnology has shown interest in the utilization of agricultural byproducts as a source for nanostructured materials. Due to their distinctive chemical, thermal, mechanical, morphological, optical, and electrical properties, cellulose nanocrystals (cNcs) have often found utility in a variety of fields. Using sulphuric acid with a 64% weight-to-weight ratio, we managed to extract cNcs chemically from rice husks for the study and examined the effects of varying the hydrolysis period and synthesized composites on optical and thermal characteristics. The usual procedure for preparation was followed, but set the hydrolysis time for 40, 60 and 90 minutes, and also varied temperature at 40˚c, 45˚c and 50˚c. Tonic water and silver nanoparticles were used to synthesize the composites at different ratios. The samples were characterized using UV-Vis spectroscopy, Fourier transform infrared (FTIR) spectroscopy, thermogravimetric analysis (TGA) and differential scanning calorimetry (DSc) techniques. From the results of this study, maximum absorption is observed to shift to shorter wavelengths with an increase in temperature, and the peak absorbance (maximum wavelength) generally increased with hydrolysis time at all three temperatures. The FTIR spectrum of cellulose nanocrystals (cNcs), AgNPs and their composites exhibited distinctive absorption bands indicative of their molecular structure and chemical composition. From the TGA findings, the two composites had a relatively low thermal stability, hence restricting their application to a fixed temperature and below. Additionally, this property makes the composite easily formable into intricate designs, which is ideal for use in optical components and sensors. The low melting point also facilitates recycling and reprocessing, enhancing sustainability by enabling the reuse of the material in various applications. Moreover, the composite’s sensitivity to temperature can be useful in temperature-sensing applications, where change

关键词： cellulose Nanocrystals Nanocomposites Silver Nanoparticles Optical Analysis Thermal Analysis Rice Husks

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Targeting TrkB–PSD-95 coupling to mitigate neurological disorders

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Neural Regeneration Research 2025年第3期20卷 715-724页

作者： Xin Yang Yu-Wen Alvin Huang john Marshall Department of Molecular Biology Cell Biology and BiochemistryBrown UniversityProvidenceRIUSA Department of Neurology Warren Alpert Medical School of Brown UniversityProvidenceRIUSA center for Translational Neuroscience Robert J.and Nancy D.Carney Institute for Brain Science and Brown Institute for Translational ScienceBrown UniversityProvidenceRIUSA

Tropomyosin receptor kinase B(TrkB)signaling plays a pivotal role in dendritic growth and dendritic spine formation to promote learning and *** activity-dependent release of brain-derived neurotrophic factor at synapses binds to pre-or postsynaptic TrkB resulting in the strengthening of synapses,reflected by long-term ***,the association of postsynaptic density protein-95 with TrkB enhances phospholipase cγ-ca^(2+)/calmodulin-dependent protein kinaseⅡand phosphatidylinositol 3-kinase-mechanistic target of rapamycin signaling required for long-term *** this review,we discuss TrkB-postsynaptic density protein-95 coupling as a promising strategy to magnify brain-derived neurotrophic factor signaling towards the development of novel therapeutics for specific neurological disorders.A reduction of TrkB signaling has been observed in neurodegenerative disorders,such as Alzheimer's disease and Huntington's disease,and enhancement of postsynaptic density protein-95 association with TrkB signaling could mitigate the observed deficiency of neuronal connectivity in schizophrenia and *** with brain-derived neurotrophic factor is problematic,due to poor pharmacokinetics,low brain penetration,and side effects resulting from activation of the p75 neurotrophin receptor or the truncated TrkB.T1 *** TrkB agonists and antibodies that activate TrkB are being intensively investigated,they cannot distinguish the multiple human TrkB splicing isoforms or cell type-specific *** TrkB–postsynaptic density protein-95 coupling provides an alternative approach to specifically boost TrkB signaling at localized synaptic sites versus global stimulation that risks many adverse side effects.

关键词： Angelman syndrome autism brain-derived neurotrophic factor depression neurodegenerative disorder neurodevelopmental disorder postsynaptic density protein-95 synaptic plasticity TrkB

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cascade degradation and electrocatalytic upcycling of waste poly(ethylene terephthalate)to valued products

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Nano Research 2025年第1期18卷 76-93页

作者： Xin Li Zirui Jiang Zongkui Kou john Wang Shiyou Zheng School of Materials and chemistry University of Shanghai for Science and TechnologyShanghai 200093China School of Materials Science and Engineering Wuhan University of TechnologyWuhan 430070China Department of Materials Science and Engineering National University of SingaporeSingapore 117574Singapore

The global annual production of poly(ethylene terephthalate)(PET)has reached 82 million tons,yet only a small fraction(less than 20%)is *** ultra-slow degradation rate of PET results in the accumulation of PET waste in the environment,causing serious plastic pollution and posing severe challenges to *** response,great efforts have been directed toward developing a cascade degradation and electrocatalytic upcycling strategy,which serves as a“waste-towealth”*** strategy involves electro-reforming PEThydrolyzed intermediates or using PET pyrolyzed products as electrocatalysts to generate high-value *** review provides an overview of the state-of-the-art strategies for the“degradation-electrocatalytic upcycling(De-eUp)”of PET ***,an introduction to the strategy is provided,categorizing it into two main frameworks:“pyrolysis-electrocatalytic upcycling”and“hydrolysis-electrocatalytic upcycling”.The section on“pyrolysis-electrocatalytic upcycling”delves into the degradation methods for designing derived carbon nanomaterials and their utilization as high-performance ***“hydrolysis-electrocatalytic upcycling”section discusses recent advancements in electro-reforming of PET hydrolyzed intermediates for the production of c_(1) and c_(2) *** review concludes by examining the challenges and future prospects in developing an efficient and economical PET upcycling *** is anticipated that this review will stimulate further progress in plastic waste valorization.

关键词： poly(ethylene terephthalate)waste electrocatalytic upcycling pyrolysis hydrolysis ethylene glycol oxidation reaction

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Limited evidence to support demineralized bone matrix in foot and ankle surgical procedures:A systematic review

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World Journal of Orthopedics 2025年第1期16卷 57-67页

作者： Hayden Hartman James J Butler Megan calton charles c Lin Samantha Rettig Jared c Tishelman Sebastian Krebsbach Grace W Randall john G Kennedy Department of Medicine Lincoln Memorial UniversityKnoxvilleTN 37752United States Department of Orthopedic Surgery NYU Langone HealthNew YorkNY 10002United States Department of Medicine Royal College of Surgeons in IrelandDublin D02 YN77LeinsterIreland

BAcKGROUND Demineralized bone matrix(DBM)is a commonly utilized allogenic bone graft substitute to promote osseous ***,little is known regarding outcomes following DBM utilization in foot and ankle surgical *** To evaluate the clinical and radiographic outcomes following DBM as a biological adjunct in foot and ankle surgical *** During May 2023,the PubMed,EMBASE and cochrane library databases were systematically reviewed to identify clinical studies examining outcomes following DBM for the management of various foot and ankle *** regarding study characteristics,patient demographics,subjective clinical outcomes,radiological outcomes,complications,and failure rates were extracted and *** addition,the level of evidence(LOE)and quality of evidence(QOE)for each individual study was also *** studies were included in this *** In total,363 patients(397 ankles and feet)received DBM as part of their surgical procedure at a weighted mean follow-up time of 20.8±9.2 *** most common procedure performed was ankle arthrodesis in 94 patients(25.9%).Other procedures performed included hindfoot fusion,1st metatarsophalangeal joint arthrodesis,5th metatarsal intramedullary screw fixation,hallux valgus correction,osteochondral lesion of the talus repair and unicameral talar cyst *** osseous union rate in the ankle and hindfoot arthrodesis cohort,base of the 5th metatarsal cohort,and calcaneal fracture cohort was 85.6%,100%,and 100%,*** weighted mean visual analog scale in the osteochondral lesions of the talus cohort improved from a pre-operative score of 7.6±0.1 to a post-operative score of 0.4±*** overall complication rate was 27.2%,the most common of which was non-union(8.8%).There were 43 failures(10.8%)all of which warranted a further surgical *** This current systematic review demonstrated that the utilization of DBM in foot and ankle surgical proced

关键词： Demineralized bone matrix Allogenic bone graft osseous union Biological adjunct Systematic review Bone morphogenetic proteins Lower limb fusion Arthrodesis

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cold plasma redistribution throughout geospace

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Science china(Technological Sciences) 2016年第9期59卷 1340-1345页

作者： Foster john c. Massachusetts Institute of Technology Haystack Observatory

The redistribution of the electrically charged cold plasma of ionospheric origin involves the equatorial,low,mid,auroral,and polar-latitude regions in a multi-step,system-wide process linking the regions of *** with ground and space-based instruments characterize the geospace plume-regularly occurring channels of enhanced plasma density flowing at both ionospheric and magnetospheric *** in the SAPS channel transports the eroded material to the noontime cusp in the ionosphere and to the dayside magnetopause at high *** the fluxes of cold plume plasma traverse the cusp and enter the polar cap,they form the polar tongue of *** the cusp the plume plasma provides a rich source of heavy ions for the magnetospheric injection and acceleration via the mechanisms operative on those field lines.

关键词： plasmasphere ionosphere geospace GPS TEc ionospheric electric field plume

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植物凝集素类受体激酶研究进展

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热带亚热带植物学报 2025年第1期33卷 107-120页

作者：熊圭 john Seymour HESLOP-HARRISON 刘青植物多样性与特色经济作物全国重点实验室广东省应用植物学重点实验室中国科学院华南植物园广州510650 中国科学院大学北京100049 莱斯特大学遗传学和基因组生物学系英国莱斯特LE17RH 华南国家植物园广州510650

植物凝集素类受体激酶(lectin receptor-like kinases, LecRLKs),隶属于植物膜蛋白类受体激酶,LecRLKs主要由胞外凝集素结构域、跨膜结构域和胞内激酶结构域组成,根据胞外结构域的特异性,分为G型、L型和c型,凝集素类受体激酶参与植物的... 详细信息

植物凝集素类受体激酶(lectin receptor-like kinases, LecRLKs),隶属于植物膜蛋白类受体激酶,LecRLKs主要由胞外凝集素结构域、跨膜结构域和胞内激酶结构域组成,根据胞外结构域的特异性,分为G型、L型和c型,凝集素类受体激酶参与植物的生长发育和环境响应调控。该文总结凝集素类受体激酶的研究历史、结构和分类,阐述植物LecRLKs的发育调控和胁迫响应功能,对功能明确的LecRLKs基因进行归类。提出凝集素类受体激酶研究中存在的不足之处,包括该家族演化历史研究极其缺乏、信号传导途径及其潜在配体亟待开展等方面。在此基础上,提出未来深入研究的方向,以期为植物凝集素类受体激酶基因家族的定向育种提供理论支持。

关键词：凝集素类受体蛋白激酶生长发育生物/非生物胁迫免疫

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Urinary Tract Infection among Pregnant Women at Pumwani Maternity Hospital, Nairobi, Kenya: Bacterial Etiologic Agents, Antimicrobial Susceptibility Profiles and Associated Risk Factors

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Advances in Microbiology 2018年第3期8卷 175-187页

作者： Hellen A. onyango carolyne Ngugi john Maina john Kiiru Department of Medical Microbiology Jomo Kenyatta University of Agriculture and Technology Nairobi Kenya Department of Medical Microbiology College of Health Sciences Jomo Kenyatta University of Agriculture and Technology Nairobi Kenya centre of Microbiology Research Kenya Medical Research Institute Nairobi Kenya

Urinary Tract Infections (UTIs) during pregnancy are among the most common infections worldwide and can lead to poor perinatal and maternal outcomes. This study determined the prevalence of UTIs during pregnancy, associated risk factors and antimicrobial susceptibility profiles of associated bacterial pathogens. A cross-sectional study was conducted among 210 pregnant women attending antenatal clinic at Pumwani Maternity hospital. Their social-demographic profiles were obtained using a structured questionnaire. cultures were done from midstream urine and antimicrobial susceptibility testing determined using the disc diffusion test. The overall prevalence of UTI was 15.7% regardless of the women’s age, parity and stage of gestation. Prevalence of asymptomatic and symptomatic bacteriuria was 4.3% and 11.4% respectively. Material of undergarment and frequency of changing the undergarments were found to contribute significantly to the acquisition of UTI (P coli was the most predominant UTI organism at (44.5%) followed by K. pneumoniae (21.2%) and S. aureus (15.1%). Almost a half (over 49%) of all Gram-negative organisms showed resistance prevalence against third generation cephalosporins, fluoroquinolones, Sulfamethoxazole-Trimethoprim, cefoxitin, Nitrofurantoin and Amoxicillin-clavulanic acid. Gram-positive strains were susceptible to Amoxicillin-clavulanic acid, Nitrofurantoin, Linezolid and Ofloxacin. The prevalence of multi-drug resistance (MDR) in all study isolates was 96%. Our data suggest a serious resistance trend among UTI strains and more should be done to slow down this trend. Pregnant women should be screened by urine culture and treatment be guided by the antimicrobial susceptibility data.

关键词： Urinary Tract Infection Pregnancy Risk Factors Antimicrobial Resistance ESBL MRSA MDR

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Estimating a Finite Population Mean under Random Non-Response in Two Stage cluster Sampling with Replacement

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Open Journal of Statistics 2017年第5期7卷 834-848页

作者： Nelson Kiprono Bii christopher Ouma onyango john Odhiambo Institute of Mathematical Sciences Strathmore University Nairobi Kenya Department of Statistics Kenyatta University Nairobi Kenya

Non-response is a regular occurrence in Sample Surveys. Developing estimators when non-response exists may result in large biases when estimating population parameters. In this paper, a finite population mean is estimated when non-response exists randomly under two stage cluster sampling with replacement. It is assumed that non-response arises in the survey variable in the second stage of cluster sampling. Weighting method of compensating for non-response is applied. Asymptotic properties of the proposed estimator of the population mean are derived. Under mild assumptions, the estimator is shown to be asymptotically consistent.

关键词： Non-Response Nadaraya-Watson Estimation Two Stage cluster Sampling

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Spatial Modelling of Weather Variables for Plant Disease Applications in Mwea Region

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Journal of Geoscience and Environment Protection 2016年第5期4卷 127-136页

作者： Paul onyango Ouma Patroba Achola Odera john Bosco Mukundi Department of Geomatic Engineering and Geospatial Information Systems Jomo Kenyatta University of Agriculture and Technology Juja Kenya Department of Horticulture and Food Sciences Jomo Kenyatta University of Agriculture and Technology Juja Kenya

climate change is expected to affect the agricultural systems, such as crop yield and plant disease occurrence and spread. To be able to mitigate against the negative impacts of climate change, there is a need to use early warning systems that account for expected changes in weather variables such as temperature and rainfall. Moreover, providing such information at high spatial and temporal resolutions can be useful in improving the accuracy of an early warning system. This paper describes a methodology that can be used to produce high spatial and temporal resolutions of minimum temperature, maximum temperature and rainfall in an agricultural area. We utilize MarkSim GcM, a weather file generator that incorporates IPcc based climate change models to downscale the weather variables at monthly intervals. An ensemble of 17 GcM models is used within the RcP 8.0 emission scenario within the latest model based cMIP5. We first assess the usability of the model, by comparing results produced to what has been recorded at weather station level over a vast region. Then, we estimate the correction factors for model results by implementing a linear regression that is used to assess the relationship between the variables and the deviation of model outputs to the weather station data. Finally, we use kriging geostatistical technique to interpolate the weather data, for the year 2010. Results indicated that the model overestimated the results of maximum temperature, while underestimating the result of minimum temperature. Variability in the recorded weather variables was also evident, indicating that the response variables such as plant disease severity dependent on such weather information could vary in the area. These datasets can be useful especially in predicting the occurrence of plant diseases, which are affected by either rainfall or temperature.

关键词： climate change Rice Blast GIS Geostatistics MarkSim GcM

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