检索结果-南通市图书馆

Sex differences in muscle health in simulated micro-and partial-gravity environments in rats

Sports Medicine and Health Science 2023年第4期5卷 319-328页

作者： Megan E.rosa-Caldwell Marie Mortreux Anna Wadhwa Ursula B.Kaiser Dong-Min Sung Mary l.Bouxsein Seward B.Rutkove Department of Neurology Beth Israel Deaconess Medical Center and Harvard Medical School330 Brookline AvenueBostonMA02215USA Department of Nutrition and Food Sciences University of Rhode IslandKingstonRI02881USA Division of Endocrinology Diabetes and HypertensionBrigham and Womenʼs Hospital and Harvard Medical SchoolBostonMA02215USA Center for Advanced Orthopedic Studies Beth Israel Deaconess Medical Center and Harvard Medical SchoolBostonMA02215USA

Skeletal muscle size and strength are important for overall health for ***,how male and female muscle may respond differently to micro-and partial-gravity environments is not fully *** purpose of this study was to determine how biological sex and sex steroid hormones influence the progression of muscle atrophy after long term exposure to micro and partial gravity environments in male and female *** and female Fisher rats(n=120)underwent either castration/ovariectomy or sham *** two weeks recovery,animals were divided into microgravity(0g),partial-gravity(40%of weight bearing,0.4g),or full weight bearing(1g)interventions for 28 *** of muscle size and strength were evaluated prior to and after *** 0g,females lost more dorsiflexion strength,plantar flexion strength,and other metrics of muscle size compared to males;castration/ovariectomy did not influence these ***,at 0.4g,females lost more dorsiflexion strength,plantar flexion strength,and other metrics of muscle strength compared to males;castration/ovariectomy did not influence these *** have greater musculoskeletal aberrations during exposure to both microgravity and partial-gravity environments;these differences are not dependent on the presence of sex steroid ***,additional interventions may be necessary to mitigate musculoskeletal loss in female astronauts to protect occupational and overall health.

关键词： Sex differences Atrophy Muscle strength Plantar flexion Dorsiflexion

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Addition of collagen type I in agarose created a dose-dependent effect on matrix production in engineered cartilage

引用

Regenerative Biomaterials 2022年第1期9卷 704-709页

作者： gabriel R.lópez-Marcial Keerthana Elango Grace D.O’Connell Department of Mechanical Engineering University of California-Berkeley6141 Etcheverry HallBerkeley CA 94720USA Department of Orthopaedic Surgery University of California-San Francisco500 Parnassus Ave MU-320WSan Francisco CA 94143USA

Extracellular-matrix composition impacts mechanical performance in native and engineered *** studies showed collagen typeⅠ-agarose blends increased cell-matrix interactions and extracellular matrix ***,long-term impacts on protein production and mechanical properties of engineered cartilage are *** objective was to characterize the effect of collagen type I on the matrix production of chondrocytes embedded in agarose *** hypothesized that the addition of collagen would improve longterm mechanical properties and matrix production(*** and glycosaminoglycans)through increased *** hydrogels(2%w/v)were mixed with varying concentrations of collagen typeⅠ(0,2 and 5 mg/ml).Juvenile bovine chondrocytes were added to the hydrogels to assess matrix production over 4 weeks through biochemical assays,and mechanical properties were assessed through unconfined *** observed a dose-dependent effect on cell bioactivity,where 2 mg/ml of collagen improved bioactivity,but 5 mg/ml had a negative impact on *** resulted in a higher modulus for scaffolds supplemented with lower collagen concentration as compared to the higher collagen concentration,but not when compared to the *** conclusion,the addition of collagen to agarose constructs provided a dose-dependent impact on improving glycosaminoglycan production but did not improve collagen production or compressive mechanics.

关键词： hydrogel tissue engineering composition agarose-collagen matrix mechanics

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

lamb-dip saturated-absorption cavity ring-down rovibrational molecular spectroscopy in the near-infrared

引用

Photonics Research 2022年第8期10卷 1803-1809页

作者： ROBERTO AIEllO VAlENTINA DI SARNO MARIA GIUlIA DEllI SANTI MAURIZIO DE rosa IOlANDA RICCIARDI GIOVANNI GIUSFREDI PAOlO DE NATAlE lUIGI SANTAMARIA PASQUAlE MADDAlONI Consiglio Nazionale delle Ricerche-Istituto Nazionale di Ottica Via Campi Flegrei 3480078 PozzuoliItaly Istituto Nazionale di Fisica Nucleare Sez.di NapoliComplesso Universitario di M.S.AngeloVia Cintia80126 NapoliItaly ppqSense S.r.l. Via Gattinella 2050013 Campi BisenzioItaly Consiglio Nazionale delle Ricerche-Istituto Nazionale di Ottica Largo E.Fermi 650125 FirenzeItaly Agenzia Spaziale Italiana Contrada Terlecchia75100 MateraItaly

The high-detection-sensitivity saturated-absorption cavity ring-down(SCAR)technique is extended to lambdip spectroscopy of rovibrational molecular transitions in the near-infrared ***-comb-referenced sub-Doppler saturation measurements,performed on the acetylene(ν_(1)+ν_(3)+ν_(4)←ν_(4))R(14)e line at6562 cm^(-1),are analyzed by a SCAR global line profile fitting routine,based on a specially developed theoretical *** to a conventional cavity ring-down evaluation,our approach yields dip profiles with a linewidth freed from saturation broadening effects,reduced by 40%,and a signal-to-noise ratio increased by 90%.Ultimately,an overall(statistical and systematic)fractional uncertainty as low as 7×10^(-12)is achieved for the absolute line-center *** the same time,our method is also able to accurately infer the linear(nonsaturated)behavior of the gas absorption,providing lamb-dip-based line strength measurements with a relative uncertainty of 0.5%.

关键词： saturated cavity absorption

来源：

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

Flow Dynamics around Two Side by Side Circular Cylinders with Alternating Movements

引用

World Journal of Mechanics 2023年第1期13卷 1-19页

作者： Alice rosa da Silva Faculty of Civil Engineering Federal University of Uberlandia Uberlandia-MG Brazil

The flow dynamics is analyzed through two-dimensional numerical simulations around two circular cylinders arranged side by side, with 4 combinations of alternating motions. All simulations are performed for Re = 1000, amplitude of oscillation (A) equal to 3, frequency ratio (fr) of 0.5, specific rotation (α) equal to 0.5 and different values of spacing ratio (l/D). It is verified that the combination of the type of movement, together with the position of one cylinder in relation to the other, exerts significant influence on the flow dynamics, as well as on the pressure distribution around the cylinder surface and on the average values of the fluid dynamics coefficients. The smallest value of the average pressure coefficient (Cp = -3.3), is obtained for the oscillating cylinder when placed side by side with the clockwise rotation cylinder, case 3 and l/D = 1.5. On the other hand, the lowest mean drag coefficient (Cd = 1.0788), is obtained for the cylinder with counterclockwise rotation, located in the lower position in relation to oscillating cylinder in the upper position, with spacing between them of 1.5. Furthermore, it is observed that the rotation movement is more effective in reducing drag than the rotation-oscillation movement, for the studied frequency ratio.

关键词： Rotation Rotation-Oscillation Flow Dynamic Circular Cylinder

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Existence of a limit Cycle in an Intraguild Food Web Model with Holling Type II and logistic Growth for the Common Prey

引用

Applied Mathematics 2017年第3期8卷 358-376页

作者： Francisco Eduardo Castillo-Santos Miguel Angel.dela rosa Iván loreto-Hernández División Académica de Ciencias Básicas CONACyT-UJAT Cunduacán México

In this paper, we prove the existence of a limit cycle for a given system of differential equations corresponding to an asymmetrical intraguild food web model with functional responses Holling type II for the middle and top predators and logistic grow for the (common) prey. The existence of such limit cycle is guaranteed, via the first lyapunov coefficient and the Andronov-Hopf bifurcation theorem, under certain conditions for the parameters involved in the system.

关键词： Hopf’s Bifurcation limit Cycle Intraguild Model

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

HP0953-hypothetical virulence factor overexpresion and localization during Helicobacter pylori infection of gastric epithelium

引用

World Journal of Gastroenterology 2022年第29期28卷 3886-3902页

作者： Nancy K Arteaga-Resendiz Gerardo E Rodea rosa María Ribas-Aparicio Alma l Olivares-Cervantes Juan Arturo Castelán-Vega Joséde Jesús Olivares-Trejo Sandra Mendoza-Elizalde Edgar O lópez-Villegas Christian Colín Pamela Aguilar-Rodea Alfonso Reyes-lópez Marcela Salazar García Norma Velázquez-Guadarrama laboratorio de Investigación en Enfermedades Infecciosas Hospital Infantil de México Federico GómezMexico City 06720Mexico Posgrado en Biomedicina y Biotecnología Molecular Laboratorio de Producción y Control de BiológicosEscuela Nacional de Ciencias BiológicasInstituto Politécnico NacionalMexico City 11340Mexico laboratorio de Adquisición de Hierro Universidad Autónoma de la Ciudad MéxicoPosgrado Ciencias GenómicaMexico City 03100Mexico laboratorio Central de Microscopía Escuela Nacional de Ciencias BiológicasInstituto Politécnico NacionalMexico City 11340Mexico Centro de estudios económicos y sociales en salud Hospital Infantil de México Federico GómezMexico City 06720Mexico laboratorio de Investigación en Biología del Desarrollo y Teratogénesis Experimental Hospital Infantil de México Federico GómezMexico City 06720Mexico

BACKGROUND The high prevalence and persistence of Helicobacter pylori(H. pylori) infection, as well as the diversity of pathologies related to it, suggest that the virulence factors used by this microorganism are varied. Moreover, as its proteome contains 340hypothetical proteins, it is important to investigate them to completely understand the mechanisms of its virulence and survival. We have previously reported that the hypothetical protein HP0953 is overexpressed during the first hours of adhesion to inert surfaces, under stress conditions, suggesting its role in the environmental survival of this bacterium and perhaps as a virulence *** To investigate the expression and localization of HP0953 during adhesion to an inert surface and against gastric(AGS) *** Expression analysis was performed for HP0953 during H. pylori adhesion. HP0953 expression at 0,3, 12, 24, and 48 h was evaluated and compared using the Kruskal-Wallis equality-of-populations rank test. Recombinant protein was produced and used to obtain polyclonal antibodies for immunolocalization. Immunogold technique was performed on bacterial sections during adherence to inert surfaces and AGS cells, which was analyzed by transmission electron microscopy. HP0953 protein sequence was analyzed to predict the presence of a signal peptide and transmembrane helices, both provided by the ExPASy platform, and using the GlYCOPP platform for glycosylation sites. Different programs, via, I-TASSER, RaptorX, and HHalign-Kbest, were used to perform three-dimensional *** HP0953 exhibited its maximum expression at 12 h of infection in gastric epithelium *** technique revealed HP0953 localization in the cytoplasm and accumulation in some peripheral areas of the bacterial body, with greater expression when it is close to AGS *** analysis revealed the presence of a signal peptide that interacts with the transmembrane region and then allows the release of the protein

关键词： Hypothetical protein HP0953 Adherence Helicobacter pylori Glycocalyx Virulence factor Persistence

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Selecting the best:Interspecific and age-related diet differences among sympatric steppe passerines

引用

Avian Research 2023年第4期14卷 611-622页

作者： Julia Zurdo Paula Gomez-lopez Adrian Barrero Daniel Bustillo-de la rosa Julia Gomez-Catasús Margarita Reverter Cristian Perez-Granados Manuel B.Morales Juan Traba Terrestrial Ecology Group Department of EcologyUniversidad Autonoma de Madrid(TEG-UAM)MadridSpain Centro de Investigacion en Biodiversidady Cambio Global Universidad Autonoma de Madrid(CIBC-UAM)MadridSpain Ecology Department/IMEM“Ramon Margalef” Universidad de AlicanteAlicanteSpain

Parental food provisioning is crucial for the growth and survival of *** rate depends on food quality and food supplied to offspring may differ from what adults use for their *** the case of steppe passerine birds,detailed characterization on nestling dietary composition,as well as prey choice and resource partitioning among species,is a pending *** differences between nestlings and adults remain also largely *** using faecal DNA metabarcoding,we described the diet of nestlings and adults of five shrub-steppe passerine species over the 2017–2019 breeding seasons in central *** also monitored arthropod availability in the field to assess dietary *** expected interspecific dietary differences to limit competition for food resources among sympatric species,as well as parental selection of high quality prey for *** also predicted age-related differences,with nestlings being fed nutrient-rich prey more frequently than *** main arthropod orders provisioned to nestlings were Orthoptera,Julida,Araneae and *** of the different species showed high interspecific diet overlap,indicating both a coincidence in growth needs among bird species and no or little limitation of the most profitable resources during the breeding *** of all species showed higher diet richness than nestlings,and age-related differences in prey composition were mainly driven by the selection of the most easily digestible,larger protein-and calcium-rich prey for nestlings,which may favour their rapid growth,and avoiding highly sclerotized and less nutritional prey such as *** study sheds light on the basic ecology and conservation of these declining steppe birds,indicating that interspecific competition may not be a major factor during the breeding *** the current global decline of arthropods,further long-term research would be necessary,along with the implementation of effective conservation measure

关键词： 18S Faecal material Nestling diet Prey choice Resource partitioning

来源：

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

Numerical analyses of pillar behavior with variation in yield criterion,dilatancy, rock heterogeneity and length to width ratio

引用

Journal of Rock Mechanics and Geotechnical Engineering 2019年第1期11卷 46-60页

作者： Sankhaneel Sinha gabriel Walton Colorado School of Mines

With recent advances in numerical modeling, design of underground structures increasingly relies on numerical modeling-based analysis approaches. While modeling tools like the discrete element method(DEM) and the combined finite-discrete element method(FDEM) are useful for investigating small-scale damage processes, continuum models remain the primary practical tool for most field-scale *** results obtained from such models are significantly dependent on the selection of an appropriate yield criterion and dilation angle. Towards improving its capabilities in handling mining-related problems, the authors have previously developed a new yield criterion(called progressive S-shaped criterion). The focus of the current study is to demonstrate its use in modeling rock pillars through a comparative analysis against four other yield criteria. In addition to the progressive S-shaped criterion,only one out of the four other criteria predicted a trend in strength consistent with an empirical pillar strength database compiled from the literature. Given the closely-knit relationship between yield criteria and dilation angle in controlling the overall damage process, a separate comparison was conducted using a mobilized dilation model, a zero degree dilation angle and a constant non-zero dilation angle. This study also investigates the impact of meso-scale heterogeneity in mechanical properties on the overall model response by assigning probability distributions to the input parameters. The comparisons revealed that an isotropic model using a combination of progressive S-shaped criterion and mobilized dilation angle model is sufficient in capturing the behaviors of rock pillars. Subsequently, the pillar model was used to assess the effect of l/W(length/width) ratio on the peak strength.

关键词： Rock pillars Progressive S-shaped criterion Numerical modeling

来源：

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

Analysis of roof and pillar failure associated with weak floor at a limestone mine

引用

International Journal of Mining Science and Technology 2016年第3期26卷 471-476页

作者： Murphy Michael M. Ellenberger John l. Esterhuizen gabriel S. Miller Tim Office of Mine Safety and Health Research National Institute of Occupational Safety and Health East Fairfield Company

A limestone mine in Ohio has had instability problems that have led to massive roof falls extending to the surface. This study focuses on the role that weak, moisture-sensitive floor has in the instability *** NIOSH research related to this subject did not include analysis for weak floor or weak bands and recommended that when such issues arise they should be investigated further using a more advanced analysis. Therefore, to further investigate the observed instability occurring on a large scale at the Ohio mine, FlAC3 D numerical models were employed to demonstrate the effect that a weak floor has on roof and pillar stability. This case study will provide important information to limestone mine operators regarding the impact of weak floor causing the potential for roof collapse, pillar failure, and subsequent subsidence of the ground surface.

关键词：石灰岩矿失效分析支柱顶板底板软弱矿山地面沉降

来源：

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

Recovery of carbon monoxide from flue gases by reactive absorption in ionic liquid imidazolium chlorocuprate(I): Mass transfer coefficients

引用

Chinese Journal of Chemical Engineering 2015年第5期23卷 769-774页

作者： gabriel Zarca Inmaculada Ortiz Ane Urtiaga Department of Chemical and Biomolecular Engineering Universidad de Cantabria Av. Los Castros s/n.

Recovery of carbon monoxide from flue gases by selective absorption of carbon monoxide in an imidazolium chlorocuprate(I) ionic liquid is considered in this work as an alternative to the use of molecular volatile solvents such as aromatic hydrocarbons. The present work evaluates the CO mass transfer rates from the gas phase to the ionic liquid solutions in the absence of chemical reaction. To that end, carbon dioxide was employed as an inert model gas and absorption experiments were performed to assess the influence of different process variables in a batch reactor with flat gas–liquid interface. The experimental mass transfer coefficients showed significant variation with temperature,(3.4–10.9) × 10-7m·s-1between 293 and 313 K; stirring speed,(10.2–33.1) × 10-7m·s-1between 100 and 300 r·min-1; and concentration of copper(I),(6.6–10.2) × 10-7m·s-1between 0.25 and 2 mol·l-1. In addition, the mass transfer coefficients were eventually found to follow a potential proportionality of the type kl∝μ-0.5and the dimensionless correlation that makes the estimation of the mass transfer coefficients possible in the studied range of process variables was obtained: Sh = 10-2.64· Re1.07·*** results constitute the first step in the kinetic analysis of the reaction between CO and imidazolium chlorocuprate(I) ionic liquid that determines the design of the separation units.

关键词：选择性吸收传质系数离子液体一氧化碳化学反应咪唑回收烟气

来源：

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

欢迎您,

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案：

请选择收藏分类：

通借通还

欢迎您,

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：