检索结果-南通市图书馆

Agro-Industrial Waste as a Source of Raw Material:Eggshell and Ash of Agave salmiana Useful for the Synthesis of Hydroxyapatite

引用

Journal of Renewable Materials 2022年第12期10卷 3559-3572页

作者： Nora Elizondo-Villarreal Luz HVerástegui-Dominguez Jose JQuijano-Briones francisco JVázquez-Rodríguez Eden Rodríguez-Castellanos Enrique López-Cuellar Ernesto Torres-Lopez Victor MCastaño-Meneses Universidad Autónoma de Nuevo León Facultad de Ciencias Fisico MatemáticasCiudad UniversitariaSan Nicolás de los GarzaNuevo LeónMéxico Universidad Autónoma de Nuevo León Facultad de ArquitecturaCiudad UniversiariaSan Nicolás de los GarzaNuevo LeónMéxico Universidad Autónoma de Nuevo León Facultad de Ingeniería Mecainicay EléctricaCiudad UniversitariaSan Nicolás de los GarzaNuevo LeónMéxico Centro de física Aplicada y Tecnología Avanzada Universidad Nacional Autonoma de MéxicoQuerétaroMéxico

Agave salmiana ash and poultry eggshell powder as CaO sources were used for obtaining nanostructured hydro-xyapatite(HAP).The synthesis was carried out by the Green Chemistry Hydrothermal Biosynthesis at 180℃ with a pH of 5,by reacting CaO from Agave Salmiana ash and Eggshell powder,with dibasic caldium phosphate(CaH-PO_(4)+2H_(2)O)in an aqueous solution,with Aloe barbadensis *** product was characterized by X-ray dif-fraction,fourier transform infrared spectroscopy(fT-IR),Scanning Electron Microscopy(SEM),and Transmission Electron Microscopy(TEM).The size and shape of the hydroxyapatite particles changed dramati-cally in the presence of Aloe *** crystals of Hydroxyapatite were observed when Eggshell powder and Agave salmiana ash were used as raw materials in the presence of the Aloe barbadensis *** with shapes of ribbons and plates from 1 micrometers to 8 micrometers were observed when using the eggshell powder in the presence of Aloe bar badensis and,in the case of Agave salmiana ash in the presence of Aloe bar-badensis,crystals with shapes of quadra ngular prisms and hexagonal(polyhedra)with sizes from 2 micrometers to 20 micrometers were *** was therefore successfully biosynthesized by a green and sus-tainable method that reduces the environmental impact.

关键词： Hydroxyapatite raw materials Agave salmiana eggshell Aloe barbadensis surfactant

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

Hummingbird-plant interactions in Chile:An ecological review of the available evidence

引用

Avian Research 2022年第3期13卷 332-340页

作者： Rodrigo Medel Manuel López-Aliste francisco E.fontúrbel departamento de ciencias Ecol ogicas Facultad de CienciasUniversidad de ChileSantiagoChile Instituto de Biología Facultad de CienciasPontificia Universidad Cat olica de ValparaísoValparaísoChile Millennium Nucleus of Patagonian Limit of Life(LiLi) ValdiviaChile

Hummingbird species have closely evolved with the plants they feed on,which is confirmed by their often tight ecological relationships in natural ***-plant interactions are of interest for research areas such as ecology,evolution,and even agriculture,as they usually inform on the conservation status of interacting species assemblages,and its disappearance may precede the population extinction of the species involved in the *** Chile,there are nine hummingbird species,which interact with a large and diverse number of angiosperm species in forest,desert,and mountain range *** motivation to perform this review is to systematize the available information regarding the flowering plants visited by hummingbird species in Chile,to present some basic plant-hummingbird pollination network metrics,and on this basis to identify the components of the plant-hummingbird relationships in need of further research.A plant-hummingbird metanetwork revealed a low connectance value,low niche overlap,and strong modularity among ***,the fact that most species present a strong allopatric distribution across Chile,suggests that network structure results mostly from the history of colonization rather than from ecological ***,the main threats to Chilean hummingbirds are anthropogenic disturbance and climate change,which disrupt hummingbird-plant interactions,leading to unpredictable ecological consequences at the community *** periods of drought may reduce the resource base for hummingbirds,with dramatic consequences for the maintenance of bird and plant populations.

关键词： Conservation Endemic species Habitat disturbance Pollination Trochilidae

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

Variation of Parameters formula and Gronwall Inequality for Differential Equations with a General Piecewise Constant Argument

引用

Acta Mathematicae Applicatae Sinica 2011年第4期27卷 561-568页

作者： Kuo-Shou CHIU Manuel PINTO departamento de matemótica Facultad de Ciencias BósicasUniversidad Metropolitana de Ciencias de la EducacinJ.P.Alessandri 774SantiagoChile departamento de matemóticas Facultad de CienciasUniversidad de ChileCasilla 653SantiagoChile

A variation of parameters formula and Gronwall type integral inequality are proved for a differential equation involving general piecewise alternately advanced and retarded argument.

关键词： variation of parameters formula Gronwall integral inequality alternately advanced and retarded argument

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

(4 + 4)-Dimensional Space-Time as a Dual Scenario for Quantum Gravity and Dark Matter

引用

Journal of Applied Mathematics and Physics 2022年第3期10卷 688-702页

作者： Brandon Mariano Martínez-Olivas Juan Antonio Nieto Andrés Sandoval-Rodríguez facultad de ciencias fsico-matemáticas de la Universidad Autónoma Culiacán Sinaloa México

In this work, we make a number of proposals to explain how a world of (4 + 4)-dimensions can be useful for a better understanding of both dark matter and quantum gravity. The key idea is to look for some advantage of considering self-dual invariants in (4 + 4)-dimensions rather than in a separate context of (1 + 3)-dimensions or (3 + 1)-dimensions. In fact, we show that by considering the duality concept in (4 + 4)-dimensions we may provide an alternative meaning of a framework for loop quantum gravity. Moreover, considering the Dirac equation in (4 + 4)-dimensions for a particle without electric charge and mass, we show that when it is projected into the (1 + 3) and (3 + 1)-worlds may describe a system with electric charge and mass. We also discuss the relation between the three physical scenarios;(4 + 4)-world, black-holes and dark matter.

关键词： (4 + 4)-Dimensions Dark Matter Quantum Gravity

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

Photoluminescence characteristics of soft PZT 53/47 ceramic doped at A and/or B sites

引用

Journal of Advanced Ceramics 2018年第2期7卷 109-116页

作者： M.D.DURRUTHY-RODRíGUEZ J.J.GERVACIO-ARCINIEGA M.HERNáNdeZ-GARCíA J.M.YánEZ-LIMóN Universidad Nacional Evangélica departamento de física Aplicada Instituto de CibernéticaMatemáticay FísicaCITMA Catedrático CONACYT-facultad de ciencias físico matemáticas Benemérita Universidad Autónoma de Puebla CINVESTAV-Unidad Querétaro del IPN Libramiento Norponiente 2000Fracc.Real de Juriquilla

This study presents the photoluminescence characteristics of the PZT 53/47 system doped at A and/or B sites, with Nb(PZTN), La(PLZT), and Nb–La(PLZTN) in the concentration range from 0.2 to 1.0 molar fraction. The intensity of the emission bands of the system PZTN is two orders higher than the intensity of the emission bands of the systems PLZT and PLZTN, and these emission bands are located at 1.73 eV(718 nm), 2.56 eV(485 nm), and 2.93 eV(424 nm). The origin of the luminescence in these systems is associated with lead and oxygen vacancies produced during the sintering process. The results from X-ray diffraction(XRD) show a mixture of rhombohedral and tetragonal phases. The system PZTN shows a higher tetragonal phase concentration, while PLZT and PLZTN systems show a higher rhombohedral phase concentration. The cell volume shows an increase with dopant concentration only in the case of the PLZTN system. The band gap energy shows a small variation in the PZTN and PLZTN cases around 3.0 eV, a close value to the band gap energy of the pure PZT 53/47 sample. The system PLZT shows an increasing behavior until 4.41 eV for the higher dopant concentration.

关键词： photoluminescence PZT ceramics band structure X-ray diffraction(XRD)

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

On Lagrange-Projection Schemes for Shallow Water flows Over Movable Bottom with Suspended and Bedload Transport

引用

Numerical Mathematics(Theory,Methods and Applications) 2023年第4期16卷 1087-1126页

作者： Alessia del Grosso Manuel J.Castro Díaz Christophe Chalons Tomás Morales de Luna UniversitéParis-Saclay UVSQCNRSLaboratoire de Mathématiques de Versailles78000VersaillesFrance Dpto.de Análisis matemático Facultad de CienciasUniversidad de MálagaCampus de Teatinos S/N29081 MálagaSpain

In the present work we aim to simulate shallow water flows over movable bottom with suspended and bedload *** order to numerically approximate such a system,we proceed step by *** start by considering shallow water equations with non-constant density of the mixture ***,the Exner equation is included to take into account bedload sediment ***,source terms for friction,erosion and deposition processes are ***,observe that the sediment particle could go in suspension into the water or being deposited on the *** the numerical scheme,we rely on well-balanced Lagrange-projection *** particular,since sediment transport is generally a slow process,we aim to develop semi-implicit schemes in order to obtain fast *** Lagrange-projection splitting is well-suited for such a purpose as it entails a decomposition of the(fast)acoustic waves and the(slow)material waves of the ***,in subsonic regimes,an implicit approximation of the acoustic equations allows us to neglect the corresponding CfL condition and to obtain fast numerical schemes with large time step.

关键词： Shallow water flows movable bottom erosion-deposition processes Lagrangeprojection schemes implicit-explicit schemes

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

Towards a Surreal Spin Theory: Surreal Superstrings?

引用

Journal of Applied Mathematics and Physics 2022年第12期10卷 3586-3600页

作者： Juan Antonio Nieto Jesús Adrián félix-Algandar facultad de ciencias fsico-matemáticas de la Universidad Autónoma de Sinaloa Culiacán Sinaloa México

We propose a surreal spin theory. Our basic mathematical tools are the dyadic rational number which is one of the key mathematical notions in surreal number theory. We argue that from the perspective of such surreal numbers, bosons and fermions, and therefore supersymmetry, are mere particular cases of a very much larger dyadic spin structure which include -spin (semionics), -spin and in general -spin, with m odd integer and n a positive natural number. finally, we conjecture that this development could imply the existence of a surreal superstring theory.

关键词： Higher Spin Theory Surreal Numbers Dyadic Rationals

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

Overcast sky condition prevails on and influences the biometeorology of the tropical Andean Páramos

引用

Journal of Mountain Science 2023年第1期20卷 78-86页

作者： Paola MONTENEGRO-DÍAZ Rolando CELLERIALVEAR Galo CARRILLO-ROJAS departamento de Recursos Hídricos y ciencias Ambientales Universidad de CuencaCuenca010207Ecuador facultad de Ingeniería Universidad de CuencaCuenca010207Ecuador facultad de ciencias Químicas Universidad de CuencaCuenca010207Ecuador

Clouds play a major role in modulating the biometeorological processes. We studied the influence of cloudiness on four biometeorological variables:daily air temperature(Tair), relative humidity(RH),reference evapotranspiration(ETr),and photosynthetic active radiation(PAR), recorded at four sites of Andean Páramos in southern Ecuador during 2.5 to 5.5 years. first, we quantified both the cloud cover percentage(Cloud%) creating cloud masks over the visible bands of Landsat 7 images and the sky condition(K_(T)) using the records of solar and extraterrestrial radiation. Second, we estimated KTfrom Cloud%. finally, we quantified T_(air), RH, ET_(r), and PAR under clear, cloudy, and overcast K_(T) and their dependence on KT. The average Cloud% ranged between 65%–76%, and KTcorroborated the prevailing overcast sky(between 55% and 72.5% of the days) over the páramos. The proposed model performed well in the sites of calibration(R^(2)= 0.80;MBE = 0.00;RMSE = 0.05) and validation(R^(2)= 0.74;MBE =-0.07;RMSE = 0.11). The overcast sky diminished T_(air)(≤ 10℃), ET_(r)(≤ 1.6 mm day-1), and PAR(4 MJ m^(-2)day^(-1)) and increased RH(≥ 88%),while the variables showed the opposite behavior during the uncommon clear sky(≤ 5.5% of the days).Thus, mostly the dynamic of RH(R^(2)≥ 0.62), ETr(R^(2)≥ 0.85), and PAR(R2≥ 0.77) depended on K_(T). Hence,the prevailing overcast sky influenced the biometeorology of the páramos.

关键词： Cloudiness indicator Clearness index Satellite imagery Tropical Andes

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

Global prevalence and gender inequalities in at least 60 min of self-reported moderate-to-vigorous physical activity 1 or more days per week:An analysis with 707,616 adolescents

引用

Journal of Sport and Health Science 2024年第5期13卷 709-716页

作者： Raphael H.O.Araujo AndrúO.Werneck Clarice L.Martins Luciana L.Barboza Rafael M.Tassitano Nicolas Aguilar-farias Gilmar M.Jesus Robinson Ramírez-Véelez Riki Tesler Adewale L.Oyeyemi Ellen C.M.Silva Robert G.Weaver Mark S.Tremblay Javier Brazo-Sayavera Grégore I.Mielke Danilo R.P.Silva Graduation Program in Health Sciences Londrina State University(UEL)Londrina 86057-970Brazil Center for Epidemiological Research in Nutrition and Health Department of NutritionSchool of Public HealthUniversidade de Sao Paulo(USP)Sao Paulo 01246-904Brazil department of Physical Education Federal University of ParaıbaParaıba 58051-900Brazil Research Centre of Physical Activity Health and LeisureFaculty of SportsLaboratory for Integrative and Translational Research in Population Health(ITR)University of PortoPorto 4500Portugal Postgraduate Program in Physical Education University of BrasıliaBrasılia 70910-900Brazil department of Kinesiology and Community Health University of Illinois at Urbana-ChampaignChampaignIL 61801-3841USA department of Physical Education Sports and RecreationUniversidad de La FronteraTemuco 4680000Chile department of Health State University of Feira de SantanaFeira de Santana 44036-900Brazil Navarrabiomed Hospital Universitario de Navarra(HUN)Navarra Institute for Health Research(IdiSNA)Universidad Publica de Navarra(UPNA)Pamplona 31006Spain facultad de ciencias de la Educacion Unidad Central del Valle del Cauca(UCEVA)TuluaValle del Cauca 763022Colombia Health Management department Faculty of Heath sciencesAriel UniversityAriel 40700Israel College of Health Solutions Arizona State UniversityPhoenixAZ 85004USA Arnold School of Public Health University of South CarolinaColumbiaSC 29208USA Healthy Active Living and Obesity Research Group Children’s Hospital of Eastern Ontario Research InstituteOttawaON K1H 8L1Canada department of Pediatrics University of OttawaOttawaON K1H 8L1Canada department of Health Sciences Carleton UniversityOttawaON K1S 5B6Canada department of Sports and Computer Science Universidad Pablo de Olavide(UPO)Seville 41013Spain Centro Universitario Regional Noreste Universidad de la RepublicaRivera 40000Uruguay School of Public Health The University of QueenslandBrisbaneQLD 4006Australia department of Physical Education

Background:Guidelines recommend that adolescents should accumulate an average of 60 min per day of moderate-to-vigorous physical activity(MVPA).However,using only this cut-off could hide important *** instance,from a population-level point of view,increasing physical activity for those with no or low physical activity could provide more health benefits than increasing physical activity for those with intermediate ***,including a more sensitive cut-point of≥1 days per week could be an additional strategy for identifying those with low access/opportunities for physical activity ***,the current study aims to estimate the prevalence of≥60 min of MVPA≥1 days per week among adolescents globally,and to describe any relevant gender ***:We used representative datasets from 146 countries/territories collected between 2003 and *** was *** were grouped into younger(≤14 years old)and older(>14 years old)*** Poisson regression models were used to identify the relative differences in≥60 min of MVPA≥1 days per week between boys and girls,and random-effects meta-analysis models were used to identify the pooled *** were stratified by country and ***:Approximately 80%of both younger and older adolescents reported≥60 min of MVPA≥1 days per *** prevalence was≥94%in Europe and Central Asia and North America,while the estimates for the other regions weref≥60 min of MVPA≥1 days per week was higher among boys than girls,with the largest differences occurring among the oldest adolescents(Prevalence ratio_(≤14y)=1.04(95%confidence interval(95%CI)):1.03-1.04)*** ratio_(>14y)=1.09(95%CI:1.08-1.10)).Conclusion:Approximately 8 out of 10 adolescents reported accumulating≥60 min of MVPA≥1 days per week,with notable differences between *** differences were observed in several countries,especially among the oldest *** fo

关键词： Global School-based Student Health Survey Health Behaviour Among School-aged Children survey Inequality Surveillance Youth

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

deciphering the role of PGC-1α in neurological disorders: from mitochondrial dysfunction to synaptic failure

引用

Neural Regeneration Research 2022年第2期17卷 237-245页

作者： Jessica D.Panes Aline Wendt Oscar Ramirez-Molina Patricio A.Castro Jorge fuentealba Laboratorio de Screening de Compuestos Neuroactivos(LSCN) Departamento de FisiologiaFacultad de Ciencias BiologicasUniversidad de ConcepcionConcepcionChile Centro de Investigaciones Avanzadas en Biomedicina(CIAB-UdeC) Facultad de Ciencias BiologicasUniversidad de ConcepcionConcepcionChile departamento de fisiologia Facultad de Ciencias BiologicasUniversidad de ConcepcionConcepcionChile

The onset and mechanisms underlying neurodegenerative diseases remain uncertain. The main features of neurodegenerative diseases have been related with cellular and molecular events like neuronal loss, mitochondrial dysfunction and aberrant accumulation of misfolded proteins or peptides in specific areas of the brain. The most prevalent neurodegenerative diseases belonging to age-related pathologies are Alzheimer's disease, Huntington's disease, Parkinson's disease and amyotrophic lateral sclerosis. Interestingly, mitochondrial dysfunction has been observed to occur during the early onset of several neuropathological events associated to neurodegenerative diseases. The master regulator of mitochondrial quality control and energetic metabolism is the transcriptional coactivator peroxisome proliferator-activated receptor gamma coactivator 1-alpha(PGC-1α). Additionally, it has been observed that PGC-1α appears to be a key factor in maintaining neuronal survival and synaptic transmission. In fact, PGC-1α downregulation in different brain areas(hippocampus, substantia nigra, cortex, striatum and spinal cord) that occurs in function of neurological damage including oxidative stress, neuronal loss, and motor disorders has been seen in several animal and cellular models of neurodegenerative diseases. Current evidence indicates that PGC-1α upregulation may serve as a potent therapeutic approach against development and progression of neuronal damage. Remarkably, increasing evidence shows that PGC-1α deficient mice have neurodegenerative diseases-like features, as well as neurological abnormalities. finally, we discuss recent studies showing novel specific PGC-1α isoforms in the central nervous system that appear to exert a key role in the age of onset of neurodegenerative diseases and have a neuroprotective function in the central nervous system, thus opening a new molecular strategy for treatment of neurodegenerative diseases. The purpose of this review is to provide an up-t

关键词： Alzheimer's disease amyotrophic lateral sclerosis Huntington's disease mitochondrial dysfunction Parkinson's disease PGC-1α synaptic function vascular dementia

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：