检索结果-南通市图书馆

BaTiO_(3)solid solutions co-doped with Gd^(3+)and Eu^(3+):Synthesis,structural evolution and dielectric properties

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 Rare Earths 2024年第10期42卷 1920-1926页

作者： R.Martínez-López M.Pérez-Labra J.A.Romero-Serrano F.R.Barrientos-Hernández M.reyes-Pérez M.I.Valenzuela-Carrillo G.Urbano-reyes V.E.reyes-Cruz G.I.Dávila-Pulido Academic Area of Earth Sciences and Materials Autonomous University of Hidalgo StateRoad Pachuca-Tulancingo Km 4.5 Mineral de La Reforma.Hidalgo42184Mexico Metallurgy and Materials Department ESIQIE-IPNUPALMZacatencoCiudad de Mexico07738Mexico Autonomous University of Coahuila Boulevard Adolfo López Mateos S/nNueva RositaCoahuila26800Mexico

In this paper,the synthesis,structural evolution,and dielectric properties of BaTiO_(3)solid solutions codoped with rare earth elements(Gd^(3+)and Eu^(3+))prepared using the solid-state reaction method are *** pure precursor powders of BaCl_3,TiO_(2),Gd_(2)O_(3),and Eu_(2)O_(3)were mixed in stoichiometric proportions,ground in an agate mortar before being uniaxially pressed at 250 MPa and sintered at 1300℃in air atmosphere for 6 h to obtain Ba_(1-3x)Gd_(2x)Ti_(1-3x)Eu_(4x)O_(3)(x=0,0.0015,0.01 and0.1).X-ray diffraction(XRD)and Rietveld's refinement results reveal the crystal phase ferroelectric tetragonal BaTiO_(3)for the samples with x=0,0.0015 and 0.01,as well as a consistent increment in the lattice parameters caused by the *** solubility limit of Gd^(3+)and Eu^(3+)in the BaTiO_(3)structure is reached for the sample with x>0.01,and the orthorhombic Eu_2TiO_(5)and monoclinic BaTi_(2)O_(5)secondary phases were *** Raman results show the characteristic peaks of ferroelectric tetragonal BaTiO_(3)around 716 cm^(-1)(LO of A1 symmetry),515 cm^(-1)(TO of A1 symmetry),and 305 cm^(-1)(B1).The maximum relative permittivity measured at 1 kHz was recorded to be 6151.8 for the sample with x=0.0015,and a decrease in the Curie temperature to 105℃with respect to the undoped sample was *** punctual microanalysis for the samples with x=0.0015,0.01,and 0.1 reveals grains composed of Ba,Ti,O,Gd,and Eu homogeneously distributed in the BaTiO_(3)*** Ba/Ti ratios for samples with x=0.0015,0.01 and 0.1 are 2.86,2.91,and 0.68,respectively,indicating substitution at the Ti site for samples with x=0.0015 and 0.01 and a substitution at the Ba site for the sample with x=0.1.

关键词： BaTiO_(3) Doping Gadolinium Europium Synthesis Rare earths

Genetic and epigenetic targets of natural dietary compounds as anti-Alzheimer's agents

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

Neural Regeneration Research 2024年第4期19卷 846-854页

作者： Willian Orlando Castillo-Ordoñez Nohelia Cajas-Salazar Mayra Alejandra Velasco-reyes Facultad de Ciencias Naturales-Exactas y de la Educación Departamento de Biología.Universidad del Cauca Departamento de Estudios Psicológicos Universidad Icesi

Alzheimer’s disease is a progressive neurodegenerative disorder and the most common cause of dementia that principally affects older *** factors,such as oxidative stress,an increase in acetylcholinesterase activity,mitochondrial dysfunction,genotoxicity,and neuroinflammation are present in this syndrome,which leads to *** pathologies such as Alzheimer’s disease are considered late-onset diseases caused by the complex combination of genetic,epigenetic,and environmental *** are two main types of Alzheimer’s disease,known as familial Alzheimer’s disease(onset<65 years)and late-onset or sporadic Alzheimer’s disease(onset≥65 years).Patients with familial Alzheimer’s disease inherit the disease due to rare mutations on the amyloid precursor protein(APP),presenilin 1 and 2(PSEN1 and PSEN2)genes in an autosomaldominantly fashion with closely 100%*** contrast,a different picture seems to emerge for sporadic Alzheimer’s disease,which exhibits numerous non-Mendelian anomalies suggesting an epigenetic component in its ***,the fundamental pathophysiological mechanisms driving Alzheimer’s disease are interfaced with epigenetic ***,the dynamic nature of epigenetics seems to open up new avenues and hope in regenerative neurogenesis to improve brain repair in Alzheimer’s disease or following injury or stroke in *** recent years,there has been an increase in interest in using natural products for the treatment of neurodegenerative illnesses such as Alzheimer’s *** epigenetic mechanisms,such as DNA methylation,non-coding RNAs,histone modification,and chromatin conformation regulation,natural compounds appear to exert neuroprotective *** we do not purport to cover every in this work,we do attempt to illustrate how various phytochemical compounds regulate the epigenetic effects of a few Alzheimer’s disease-related genes.

关键词： Alzheimer’s disease epigenetics genes methylation natural products

Breaking paradigms: Long non-coding RNAs forming gene fusions with potential implications in cancer

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

Genes & Diseases 2024年第3期11卷 311-323页

作者： David Sanchez-Marin Macrina Beatriz Silva-Cazares Fany Iris Porras-reyes Rebeca Garcia-Roman Alma D.Campos-Parra Posgrado en Ciencias Biologicas Facultad de MedicinaUniversidad Nacional Autonoma de MexicoCiudad de MexicoC.P.04360Mexico Unidad Academica Multidisciplinaria Region Altiplano Universidad Autonoma de San Luis Potost(UASLP)Carretera a Cedral Km 5+600Ejido San Jose de la TrojesMatehualaSan Luis PotosiC.P.78760Mexico Servicio de Anatomia Patologica Instituto Nacional de Cancerologia(INCan)Nino JesuisTlalpanCiudaddeMexicoC.P.14080Mexico Instituto de Salud Publica Universidad Veracruzana(UV)Av.Dr LuisDr.Castelazo Ayala s/nCol.Industrial AnimasXalapaVeracruzC.P.91190Mexico

Long non-coding RNAs(lncRNAs)are non-coding RNAs longer than 200 nucleotides with dynamic regulatory *** interact with a wide range of molecules such as DNA,RNA,and proteins to modulate diverse cellular functions through several mechanisms and,if deregulated,they can lead to cancer development and ***,it has been described that IncRNAs are susceptible to form gene fusions with mRNAs or other IncRNAs,breaking the paradigm of gene fusions consisting mainly of protein-coding ***,their biological significance in the tumor phenotype is still ***,their recent identification opens a new line of research to study their biological role in tumor-igenesis,and their potential as biomarkers with clinical relevance or as therapeutic *** present study aimed to review the IncRNA fusions identified so far and to know which of them have been associated with a potential *** address the current challenges to deepen their study as well as the reasons why they represent a future therapeutic window incancer.

关键词： Cancer Genefusions IncRNAs ncRNAs Therapy

CONSTANS alters the circadian clock in Arabidopsis thaliana

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 2024年第8期17卷 1204-1220页

作者： Pedro de los reyes Gloria Serrano-Bueno Francisco J.Romero-Campero He Gao Jose M.Romero Federico Valverde Plant Development Group-Institute for Plant Biochemistry and Photosynthesis Consejo Superior de Investigaciones CientificasUniversidad de SevillaSevilleSpain Department of Computer Science and Artificial Intelligence Universidad de SevillaSevilleSpain Department of Plant Developmental Biology Max Planck Institute for Plant Breeding ResearchCologneGermany Department of Plant Biochemistry and Molecular Biology Universidad de SevillaSevilleSpain

Plants are sessile organisms that have acquired highly plastic developmental strategies to adapt to the *** these processes,the floral transition is essential to ensure reproductive success and is finelyregulated by several internal andexternal genetic *** photoperiodic pathway,which controls plant response to day length,is one of the most important pathways controlling *** Arabidopsis photoperiodic flowering,CONSTANS(CO)is the central gene activating the expression of the florigen FLOWERING LOCUS T(FT)in the leaves at the end of a long *** circadian clock strongly regulates Co ***,to date,no evidence has been reported regarding a feedbackloop from the photoperiod pathway back to the circadian *** transcriptional networks,we have identified relevant network motifs regulating the interplay between the circadian clock and the photoperiod *** expression,chromatin immunoprecipitation experiments,and phenotypic analysis allowed us to elucidate the role of Co over the circadian *** with altered cO expression showed a different internal clock period,measured by daily leaf rhythmic *** showed that co upregulates the expression of key genes related to the circadian clock,such as CCA1,LHY,PRR5,and Gl,at the end of a long day by bindingto specific sites on their ***,a high numberof PRR5-repressed target genes are upregulated by CO,and this could explain the phase transition promoted by *** CO-PRR5 complex interacts with the bZiP transcriptionfactor HY5andhelps to localize the complex in the promoters of clock *** together,our results indicate that there may be a feedback loop in which co communicates back to the circadian clock,providing seasonal information to the circadian system.

关键词： CONSTANS circadian clock photoperiod

La modernización con caracteristicas chinas

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

今日中国（西文版） 2024年第3期 40-41页

作者： MILTON reyes HERRERA 不详

Effect of the Density of Molten Metal on the Raining Phenomenon in Horizontal Centrifugal Casting

维普期刊数据库博看期刊评论

在线全文

学校读者我要写书评

暂无评论

Open Journal of Applied Sciences 2024年第7期14卷 1918-1926页

作者： Miguel A. Barron Joan reyes Departamento de Materiales Universidad Autonoma Metropolitana Azcapotzalco Ciudad de Mexico Mexico

In this work the influence of the density of the molten metal on the emergence of the raining phenomenon in the horizontal centrifugal casting process is numerically studied. Transient 2D numerical simulations were carried out using Computational Fluid Dynamics software. Three molten metals with different density, namely aluminum, iron and lead, and three angular frequencies, namely 50, 66 and 77 rad/s were considered. It is found that the density of the molten metal significantly affects the emergence, transient or permanent, of the rain phenomenon. However, the magnitude and duration of the rain phenomenon depend on the angular frequency of the rotating mold. Likewise, since gravitational forces affect the metal according to its density, the value of the critical rotation speed of the mold is also affected.

关键词： Angular Frequency Centrifugal Force Computational Fluid Dynamics Critical Rotation Speed G Factor Horizontal Centrifugal Casting Molten Metal Density

Temperature Drop of Molten Metals in Open Channels

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

World Journal of Engineering and Technology 2024年第3期12卷 493-500页

作者： Miguel A. Barron-Meza Joan reyes-Miranda Departamento de Materiales Universidad Autonoma Metropolitana Azcapotzalco Ciudad de Mexico Mexico

The temperature drop of molten metal flowing in open channels is numerically determined. Rectangular, trapezoidal and triangular geometries are considered. The overall heat transfer coefficients for the bottom, side walls and free surface of the channel have been taken from the literature. For each geometry, the volumetric flow rate, mean residence time and temperature drop as a function of the channel inclination angle were determined. The rectangular and trapezoidal geometries present the smallest temperature drops, while the triangular geometry presents the greatest temperature drop. The factors that most affect this drop are the value of the free surface area of the channel, and the average residence time of the molten metal in the channel.

关键词： Free Surface Heat Transfer Molten Metal Open Channel Geometry Residence Time Temperature Drop

Non-Darcy Flow in Molding Sands

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Open Journal of Applied Sciences 2024年第4期14卷 976-982页

作者： Miguel A. Barron-Meza Joan reyes-Miranda Daniel Flores-Sanchez Departamento de Materiales Universidad Autonoma Metropolitana Azcapotzalco Ciudad de Mexico Mexico

Darcy’s law is widely used to describe the flow in porous media in which there is a linear relationship between fluid velocity and pressure gradient. However, it has been found that for high numbers of Reynolds this law ceases to be valid. In this work, the Ergun equation is employed to consider the non-linearity of air velocity with the pressure gradient in casting sands. The contribution of non-linearity to the total flow in terms of a variable defined as a non-Darcy flow fraction is numerically quantified. In addition, the influence of the shape factor of the sand grains on the non-linear flow fraction is analyzed. It is found that for values of the Reynolds number less or equal than 1, the contribution of non-linearity for spherical particles is around 1.15%.

关键词： Darcy’s Law Molding Sands Non-Darcy Flow Reynolds Number Shape Factor

Beyond the imaging evaluation of fractures of the lateral process of the talus:Let’s not forget concomitant injuries

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

World Journal of Clinical Cases 2024年第30期12卷 6410-6412页

作者： Cristian Lindner Pedro reyes Eduardo Molina Andrés Olave Department of Radiology Faculty of MedicineUniversity of ConcepciónConcepción 4030000BiobíoChile Department of Radiology Hospital Regional Guillermo Grant BenaventeConcepción 4030000BiobíoChile Department of Musculoskeletal Radiology Hospital Regional Guillermo Grant BenaventeConcepción 4030000BiobíoChile

Fractures of the lateral process of the talus(FLPT)are uncommon fractures that represent a clinical *** radiological classification systems rely predominantly on radiographic ***,due to the high rate of FLPT misdiagnosis and the limited accuracy in evaluating concomitant talar injuries through plain radiographs,novel imaging classification systems have been developed that aim to enhance the diagnosis of concomitant talar injuries,thereby optimizing patient management and reducing the incidence of long-term complications.

关键词： Talus Bone fracture Subtalar joint Hindfoot injuries Fracture of the talus Intraarticular fracture