检索结果-南通市图书馆

The benefits of being dominant:health correlates of male social rank and age in a marmot

在线全文

学校读者我要写书评

暂无评论

Current Zoology 2022年第1期68卷 19-26页

作者： Kenta UCHIDA Rachel NG Samuel A.VYDRO jennifer e.SMITH Daniel T.BLUMSTeIN Department of ecology&evolutionary Biology University of CaliforniaLos AngelesCA 90095-1606USA Department of Biology Mills CollegeOaklandCA 94613USA The Rocky Mountain Biological laboratory Crested ButteCO 81224USA

The benefits of dominance may not come without costs,particularly for *** example,the“immunocompetence handicap hypothesis”states that males with enhanced mating success allocate resources to enhance reproductive output at a cost to their current health,whereas the“resource quality hypothesis”predicts that high-ranking males may benefit from increased reproduction and good *** the predictions from each have been well tested in captive animals and in a variety of highly social primates,fewer studies have been carried out in free-living,facultatively social *** adult male yellow-bellied marmots(Marmota flaviventer),we evaluated predictions of these hypotheses by examining the relationship between social rank and 2 health indicators—fecal glucocorticoid metabolite(FCM)levels,and neutrophil/lymphocyte(N/L)ratios—after accounting for variation explained by age,body mass,and *** found that higher-ranking males tended to have a lower N/L ratio(reflecting good health)than lower-ranking individuals,whereas FCM levels were not significantly related to *** addition,heavier male marmots had lower N/L ratios,whereas body mass was not associated with FCM *** also found that older adult males had lower FCM levels(reflecting less physiological stress)but higher N/L ratios than younger ***,we found that FCM levels decreased as the active season progressed and FCM levels were associated with the time of the ***,our results suggest that socially-dominant male marmots enjoyed better,not worse health in terms of lower N/L ratios.

关键词： immunocompetence handicap hypothesis life history trade-offs N/L ratio physiological stress resource quality hypothesis

Dental microwear of sympatric rodent species sampled across habitats in southern Africa: Implications for environmental influence

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Integrative Zoology 2016年第2期11卷 111-127页

作者： Jenny H.e.BURGMAN jennifer LeICHLITeR Nico L.AVeNANT Peter S.UNGAR environmental Dynamics Program University of ArkansasFayettevilleArkansasUSA Department of Anthropology University of Colorado BoulderBoulderColoradoUSA National Museum and University of the Free State BloemfonteinSouth Africa Department of Anthropology University of ArkansasFayettevilleArkansasUSA

Dental microwear textures have proven to be a valuable tool for reconstructing the diets of a wide assortment of fossil ***,some studies have recently questioned the efficacy of this approach,suggesting that aspects of habitat unrelated to food preference,especially environmental grit load,might have a confounding effect on microwear patterning that obscures the diet *** we evaluate this hypothesis by examining microwear textures of 3 extant sympatric rodent species that vary in diet breadth and are found in a variety of habitat types:Mastomys coucha,Micaelamys namaquensis and Rhabdomys *** sample each of these species from 3 distinct environmental settings in southern Africa that differ in rainfall and vegetative cover:Nama-Karoo shrublands(semi-desert)and Dry Highveld grasslands in the Free State Province of South Africa,and Afromontane(wet)grasslands in the highlands of *** differences between habitat types are evident for some of the species,inconsistency in the pattern suggests that the microwear signal is driven by variation in foods eaten rather than grit-level per *** is clear that,at least for species and habitats sampled in the current study,environmental grit load does not swamp diet-related microwear signatures.

关键词： diet grit tooth wear

Seasonal shifts in the solute ion ratios of vadose zone rock moisture from the eel River Critical Zone Observatory

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Acta Geochimica 2017年第3期36卷 385-388页

作者： jennifer L.Druhan Nicole Fernandez Jia Wang William e.Dietrich Daniella Rempe Department of Geology University of Illinois Urbana Champaign Department of earth and Planetary Science University of California Berkeley Jackson School of Geosciences University of Texas at Austin

One of the greatest challenges in critical zone studies is to document the moisture dynamics, water flux,and solute chemistry of the unsaturated, fractured and weathered bedrock that lies between the soil and groundwater table. The central impediment to quantifying this component of the subsurface is the difficulty associated with direct observations. Here, we report solute chemistry as a function of depth collected over a full year across the shale-derived vadose zone of the eel River Critical Zone Observatory using a set of novel sub-horizontal wellbores,referred to as the vadose zone monitoring system. The results of this first geochemical glimpse into the deep vadose zone indicate a dynamic temporal and depth-resolved structure. Major cation concentrations reflect seasonal changes in precipitation and water saturation, and normalized ratios span the full range of values reported for the world's largest rivers.

关键词： Vadose zone Solute ion ratios Critical Zone Observatory Seasonal solute dynamics

Tooth loss patterns in older adults with special needs:a Minnesota cohort

在线全文

学校读者我要写书评

暂无评论

International Journal of Oral Science 2011年第1期3卷 27-33页

作者： jennifer J.Clark Department of Dental ecology University of North CarolinaChapel HillNC 27599USA

This study was conducted to detail tooth loss patterns in older adults with special needs. A total of 491 elderly subjects with special needs were retrospectively selected and followed during 10/1999-12/2006. Medical, dental, cognitive, and functional assessments were abstracted from dental records and used to predict risk of tooth loss. Tooth loss events were recorded for subjects during follow-up. Chi-squared tests were used to study the association between tooth loss and the selected risk factors. Logistic, poisson, and negative binomial regressions were developed to study tooth loss patterns. Overall, 27% of the subjects lost at least one tooth during follow-up. Fourteen subjects had tooth loss events per 100 person-years. Tooth loss pattern did not differ significantly among different special-needs subgroups （i.e. community-dwelling vs. long-term care, physically disabled vs. functionally independent）. Special-needs subjects with three or more active dental conditions at arrival had more than twice the risk of losing teeth than those without any existing conditions. After adjusting other factors, the number of carious teeth or retained roots at arrival was a significant predictor of tooth loss for older adults with special needs （P=0.001）. These findings indicate that appropriately managing active caries and associated conditions is important to prevent tooth loss for older adults with special needs.

关键词： tooth loss elderly special needs

Androgen and estrogen receptors in placental physiology and dysfunction

在线全文

学校读者我要写书评

暂无评论

Frontiers in Biology 2018年第5期13卷 315-326页

作者： erin S McWhorter jennifer e Russ Quinton A Winger Gerrit J Bouma Department of Biomedical Sciences Animal Reproduction and Biotechnology Laboratory Colorado State University. 1683 Campus deliveryFort Collins CO 80523-1683 USA

BACKGROUND： The placenta is recognized as an endocrine organ, largely due to its secretions of steroid hormones, including progesterone, androgens, and estrogens. Steroid hormones play an essential role in the progression of pregnancy, fetal development, and growth. Furthermore, steroids are necessary for establishment and maintenance of a normal pregnancy, preparing the endometrium for implantation, stimulating endometrial secretions, and regulating uterine blood flow, however the exact mechanism of sex steroid signaling through their receptors in placental function is unknown. OBJeCTIVe： In this review, we will provide an overview of the current knowledge on sex steroid receptors in normal placental development, as well as evidence of abnormal signaling associated with placental dysfunction. MeTHODS： A systematic literature search was performed using the NCBI PubMed search engine, including the following key works： estrogen receptor, androgen receptor, placenta, placental development, cytotrophoblast, and differentiation. ReSULTS： Of the over 700 articles that were returned, 125 studies focused on estrogen and androgen receptors in human placenta development and function during normal and abnormal pregnancy, as well as in rodents and ruminants placentae. CONCLUSION： Receptors for both estrogens and androgens have been localized within the mammalian placenta, but surprisingly little is known about their signaling in trophoblast cell differentiation and function. An emerging picture is developing in which estrogen receptors possibly play role in cytotrophoblast proliferation and extravillous trophoblast invasion, whereas androgen receptors are involved in syncytiotrophoblast differentiation and function.

关键词： Placenta eSR AR preeclampsia IUGR PCOS

evaluation of the plasmonic effect of Au and Ag on Ti-based photocatalysts in the reduction of CO2 to CH4

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 energy Chemistry 2017年第2期26卷 277-283页

作者： Martin Dilla Anna Pougin jennifer Strunk Max-Planck-Institute for Chemical energy conversion Stiftstraße 34-3645470 Mülheim/RuhrGermany laboratory of Industrial Chemistry Ruhr-University BochumUniversitätsstraße 15044780 BochumGermany Center for Nanointegration Duisburg-essen University of Duisburg-EssenCarl-Benz-Straße 19947057 DuisburgGermany

Crystalline TiO（P25） and isolated titanate species in a ZSM-5 structure（TS-1） were modified with Au and Ag, respectively, and tested in the gas-phase photocatalytic COreduction under high purity conditions. The noble metal modification was performed by photodeposition. Light absorbance properties of the catalysts are examined with UV–Vis spectroscopy before and after the activity test. In the gas-phase photocatalytic COreduction, it was observed that the catalysts with Ag nanostructures are more active than those with Au nanostructures. It is thus found that the energetic difference between the band gap energy of the semiconductor and the position of the plasmon is influencing the photocatalytic ***, plasmon excitation due to visible light absorption results in plasmon resonance energy, which affects the excitation of the semiconductor positively. Therefore, an overlap between band gap energy of the semiconductor and metal plasmon is needed.

关键词： Photocatalytic CO2 reduction Plasmon resonance Methane formation TS-1 P25 Noble metal photodeposition High-purity gas-phase photoreactor

Cdc42 regulates the cellular localization of Cdc42ep1 in controlling neural crest cell migration

在线全文

学校读者我要写书评

暂无评论

Journal of Molecular Cell Biology 2018年第5期10卷 376-387页

作者： Shlomi Cohen Daniel T. Kovari Wenbin Wei Rebecca Keate jennifer e. Curtis Shuyi Nie School of Biological Sciences Georgia institute of Technology Atlanta GA 30332 USA School of Physics Georgia Institute of Technology Atlanta GA 30332 USA Petit Institute for Bioengineering and Bioscience Georgia Institute of Technology Atlanta GA 30332 USA Department of Physics Emory University Atlanta GA 30322 USA Wallace H. Coulter Department of Biomedical engineering Georgia institute of Technology Atlanta GA 30332 USA

The member of Rho family of small GTPases Cdc42 plays important and conserved roles in cell polarity and motility. The Cdc42ep family proteins have been identified to bind to Cdc42, yet how they interact with Cdc42 to regulate cell migration remains to be elucidated. In this study, we focus on Cdc42epl, which is expressed predominantly in the highly migratory neural crest ceils in frog embryos. Through morpholino-mediated knockdown, we show that Cdc42epl is required for the migration of cranial neural crest cells. Loss of Cdc42epl leads to rounder cell shapes and the formation of membrane blebs, consistent with the observed disruption in actin organization and focal adhesion alignment. As a result, Cdc42ep1 is critical for neural crest cells to apply traction forces at the correct place to migrate efficiently. We further show that Cdc42ep1 is localized to two areas in neural crest celts： in membrane protrusions together with Cdc42 and in perinuciear patches where Cdc42 is absent. Cdc42 directly interacts with Cdc42epl （through the CRIB domain） and changes in Cdc42 level shift the distribution of Cdc42epl between these two subcellular locations, controlling the formation of membrane protrusions and directionality of migration as a consequence. These results suggest that Cdc42ep1 elaborates Cdc42 activity in neural crest cells to promote their efficient migration.

关键词： actin cytoskeleton neural crest Rho GTPases Cdc42 effector protein 1 cell migration

Ultraviolet light exposure and its penetrance through the eye in a porcine model

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

International Journal of Ophthalmology(english edition) 2023年第2期16卷 172-177页

作者： Hideki Fukuoka Helena e.Gali jennifer J.Bu Ruti Sella Natalie A.Afshari Shiley eye Institute Viterbi Family Department of OphthalmologyUniversity of California San DiegoLa JollaCA 92093USA

AIM:To determine the amount of ultraviolet(UV)light irradiance that various layers of the eye receive as sunlight passes through the eye,and to investigate the protective benefits of UV light-blocking contact ***:Twenty-four porcine eyes were prepared in one of three ways:isolated cornea,cornea and lens together,or whole eye *** light irradiance was measured with a UV-A/B light meter before and after the eye preparations were placed over the meter to measure UV light penetration in each eye *** the whole eye preparation,a hole was placed in the fovea to measure light as it passed through the ***,UVprotective contact lenses were placed over the structures,and UV light penetrance was *** of UV light exposure were taken outdoors at various locations and ***:Cornea absorbed 63.56%of UV light that reached the *** and lens absorbed 99.34%of UV *** eye absorbed 99.77%of UV *** UV-protective contact lenses were placed,absorption was 98.90%,99.55%,and 99.87%,*** light exposure was dependent on directionality and time of day,and was greatest in areas of high albedo that reflect significant amounts of light,such as a ***:Cornea absorbs the majority of UV light that reaches the eye in this ***-protective contact lenses reduce UV exposure to the *** with high albedo expose the eye to higher levels of UV light.

关键词： ultraviolet light penetrance contact lens cornea lens

Virus-Induced Gene Silencing in the Culinary Ginger （Zingiber officinale）： An effective Mechanism for Down-Regulating Gene expression in Tropical Monocots

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Molecular Plant 2009年第5期2卷 1084-1094页

作者： Tanya Renner jennifer Bragg Heather e. Driscoll Juliana Cho Andrew O. Jackson Chelsea D. Specht Department of Plant and Microbial Biology University of California Berkeley CA 94720 USA Present address: Genornics and Gene Discovery USDA ARS PWA WRRC-GGD 800 Buchanan Street Albany CA 94710 USA

Virus-induced gene silencing （VIGS） has been shown to be effective for transient knockdown of gene expression in plants to analyze the effects of specific genes in development and stress-related responses. VlGS is well established for studies of model systems and crops within the Solanaceae, Brassicaceae, Leguminaceae, and Poaceae, but only recently has been applied to plants residing outside these families. Here, we have demonstrated that barley stripe mosaic virus （BSMV） can infect two species within the Zingiberaceae, and that BSMV-VIGS can be applied to specifically down-regulate phytoene desaturase in the culinary ginger Zingiber officinale. These results suggest that extension of BSMV-VlGS to monocots other than cereals has the potential for directed genetic analyses of many important temperate and tropical crop species.

关键词： Barley stripe mosaic virus virus-induced gene silencing VIGS Zingiber officinale Monocot.