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

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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

The Beauty of Being a Variant： H2A.Z and the SWR1 Complex in Plants

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Molecular Plant 2009年第4期2卷 565-577页

作者： Rosana March-Diaz Jose C. reyes Andalusian Center for Molecular Biology and Regenerative Medicine (CABIMER) CSIC Americo Vespucio s/n E-41092 Sevilla Spain

Numerous studies have shown that the nucleosome is a dynamic structure that strongly influences gene expression. Dynamism concerns different nucleosomal characteristics, including position, posttranslational modifications, and histone composition. Thus, within the nucleosome, canonical histones can be exchanged by histone variant proteins with specific functions--a process known as ‘histone replacement＇. The histone variant H2A.Z has an important function in transcription and, during the last few years, its role in plant development and immune response has become evident. Compiling genetic and biochemical studies from several laboratories has revealed that plants contain a multiprotein complex, similar to the SWR1/SRCAP complex from yeast and animals, involved in H2A.Z deposition. Despite intense research in different organisms, the mechanism by which H2A.Z influences transcription is still unknown. However, recent results from Arabidopsis have shown a strong inverse correlation between H2A.Z and DNA methylation, suggesting that H2A.Z might protect genes from silencing.

关键词： Chromatin structure and remodeling epigenetics gene regulation floral induction.

Neural functions of small heat shock proteins

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Neural Regeneration Research 2022年第3期17卷 512-515页

作者： Teresa de los reyes Sergio Casas-Tintó Instituto Cajal CSICMadridSpain

Stress response is a cellular widespread mechanism encoded by a common protein program composed by multiple cellular factors that converge in a defense reaction to protect the cell against *** many mechanisms described,heat shock proteins were proposed as universally conserved protective factors in the stress core proteome,coping with different stress stimuli through its canonical role in protein ***,emerging evidences reveal non-canonical roles of heat shock proteins relevant for physiological and pathological ***,we review the implications of inducible heat shock proteins in the central nervous system *** particular,we discuss the relevance of heat shock proteins in the maintenance of synapses,as a balanced protective mechanism in central nervous system development,pathological conditions and aging.

关键词： aging central nervous system chaperones environment neuroprotection pathology stress synapses

Mind the gap among patches in arid plant communities:rapid root proliferation in response to N addition

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Journal of Plant Ecology 2019年第1期12卷 89-95页

作者： Maria Fernanda reyes Martín RAguiar Instituto de Investigaciones Fisiológicas y Ecológicas Vinculadas a la Agricultura(IFEVA)and Consejo Nacional de Investigaciones Científicas y Técnicas(CONICET) Universidad de Buenos AiresAv.San Martín 4453Buenos Aires C1417DSEArgentina

Aims In arid communities,it has been proposed that individual plants can extend their roots beyond their canopy exploring neighbour-ing bare ground *** becomes relevant in systems where the vegetation is distributed in patches surrounded by bare ***,whether roots of different species may be overlapping under bare ground areas is still *** factors control-ling root responses when no plants appear to be directly influ-encing the gap among patches are still *** aim of our study was to detect perennial grasses responses to an N enrich-ment *** In a semi-arid steppe(Patagonia,Argentina),we buried root traps filled with sieved soil with and without N addition,under bare soil *** were harvested after 4 and 6 *** neighbour-hoods(30 cm in diameter)included at least three of the dominant tussock *** harvests,we identified species in the traps by root traits and quantified diversity,biomass and specific relative growth *** Findings Bare ground areas show simultaneous root growth of different *** of perennial grass roots was higher with N addition than without it in the first harvest(4 months),but this difference disappeared in the second harvest(6 months).Root biomass was maximal after 6 months in N addition *** preferred by herbivores(Bromus pictus and Poa ligularis)showed rapid growth and responses to N *** between harvests may be an indicative that N pulses interact with rising temperatures and soil water content as growing season progress.

关键词： belowground community ecology grass species roots Patagonian steppe patchiness root growth rates zone of influence

Bifurcated Rhodaelectro-catalyzed C−H Activation for the Synthesis of Pyrroles and lactones

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Precision Chemistry 2023年第6期1卷 382-387页

作者： Simon l.Homölle Maximilian Stangier fraim reyes lutz Ackermann Institut für Organische und Biomolekulare Chemie Georg-August-Universität Göttingen37077 GöttingenGermany University of the Basque Country(UPV/EHU) 48940 LeioaBizkaiaSpain DZHK(German Centre for Cardiovascular Research) 10785 BerlinGermany

While electrocatalyzed alkyne annulations of arenes represent a powerful strategy for the assembly of heteroaromatic motives,electrochemical C(sp2)−H activations of alkenes remain ***,a strategy for the rhodaelectro-catalyzed function-alization of enamides is presented for the efficient construction of pyrroles using electricity as a sustainable ***,the tuning of the solvent system allowed a fascinating switch in chemoselectivity,which is not possible with traditionally used chemical oxidants,giving rise to lactone *** rhoda-electrocatalysis features a broad scope as well as high regio-and chemoselectivities.

关键词： C−H activation rhodium bifurcated electrochemistry sustainability pyrrole lactone

Removing contaminants from tannery wastewater by chemical precipitation using CaO and Ca(OH)2

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Chinese Journal of Chemical Engineering 2020年第4期28卷 1107-1111页

作者： Adriana reyes-Serrano Joel Elópez-Alejo Manuel AHernández-Cortázar Ignacio Elizalde Instituto Politécnico Nacional Centro Mexicano para la Producción más LimpiaCiudad de México 07340Mexico

The removal of Cr,sulfates and Chemical Oxygen Demand(COD)from industrial tannery wastewater by chemical precipitation was carried out using Calcium oxide(CaO)and Calcium hydroxide(Ca(OH)2).Different doses of alkalis,ranging from deficiency to excess hydroxyl species over the stoichiometric necessary,were used to remove theoretically the 100%of Cr[0.3-3.2 g alkali·(g Cr^3+)^-1].The precipitation was carried out at room temperature,10 min of vigorous stirring,200 r·min^-1 and a settling time of 24 h,followed by separation and characterization of liquid *** result of addition of alkalis,pH underwent increase as did the alkali *** removal of Cr,and sulfates also increased as alkali concentration did,although for first species the changes at higher alkali contents were less *** removal on the other hand,did not follow a unique trend,instead exhibited a *** on our results,selection of a specific dose of alkali was carried out taking as reference the efficiency on total chromium removal,keeping the pH in the range 7 to 9 to ensure Cr precipitation as chromium *** those conditions,jar test was used to produce enough liquid product in order to determine the removal percent of several other *** removal percent of the species was as follows:Cr,SO4^2-,ZnSO4,FeSO4,CN^-1,NiSO4,Fe2[Fe(CN)6]at 99.8%,66.9%,99.6%,21.4%,70.9%,52.8%and 76.4%with CaO,and 99.8%,61.6%,99.9%,7.1%,84.0%,54.4%and 90.5%with Ca(OH)2,respectively.

关键词： Tannery wastewater Alkali Removal Chromium Sulfates Synergistic effect

Hypothalamic-pituitary-adrenal axis function during perinatal depression

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Neuroscience Bulletin 2015年第3期31卷 338-350页

作者： Phillipe leff Gelman Mónica Flores-Ramos Margarita lópez-Martínez Carlos Cruz Fuentes Juan Pablo reyes Grajeda National Institute of Perinatology Mexico City National Council of Sciences and Technology (CONACy T) Mexico City National Institute of Psychiatry Mexico City National Institute of Genomic Medicine Mexico City

Abnormal function of the hypothalamic-pituitary-adrenal （HPA） axis is an important pathological finding in pregnant women exhibiting major depressive disorder. They show high levels of cortisol pro- inflammatory cytokines, hypothalamic-pituitary peptide hormones and catecholamines, along with low dehydroepiandrosterone levels in plasma. During pregnancy, the TH2 balance together with the immune system and placental factors play crucial roles in the development of the fetal allograft to full term. These factors, when altered, may generate a persistent dysfunction of the HPA axis that may lead to an overt transfer of cortisol and toxicity to the fetus at the expense of reduced activity of placental 1113-hydroxysteroid dehydrogenase type 2. Epigenetic modifications also may contribute to the dysregulation of the HPA axis. Affective disorders in pregnant women should be taken seriously, and therapies focused on preventing the deleterious effects of stressors should be implemented to promote the welfare of both mother and baby.

关键词： brain depression neuroendocrine pregnancy stress glucocorticoids

Targeting BCl2 pathways in Cll: a story of resistance and ingenuity

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Cancer Drug Resistance 2023年第4期6卷 828-837页

作者： Amanda reyes Tanya Siddiqi Hematology&Oncology City of HopeDuarteCA 91010USA Hematology/HCT City of HopeDuarteCA 91010USA

Chronic lymphocytic leukemia(Cll)is common amongst leukemic malignancies,prompting dedicated investigation throughout the *** the last decade,the treatment for Cll has significantly advanced with agents targeting B-cell lymphoma 2(BCl2),Bruton's tyrosine kinase,and *** agents or combinations of these targets have proven ***,resistance to one or multiple of the new treatment targets *** review investigates various mechanisms of resistance to BCl2 inhibitors,including mutations in BCl2,alterations in the Bcl protein pathway,epigenetic modifications,genetic heterogeneity,Richter transformation,and alterations in oxidative ***,the review will discuss potential avenues to overcome this resistance with novel agents such as bispecific antibodies,Bruton's tyrosine kinase(BTK)degraders,non-covalent BTK inhibitors,and chimeric antigen receptor T(CART).

关键词： BCl-2 inhibitors apoptosis Cll resistance tumor microenvironments cell cycle regulation genetic mutations epigenetics richter transformation

local Phase Portraits through the Newton Diagram of a Vector Field

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Acta Mathematica Sinica,English Series 2015年第6期31卷 1015-1034页

作者： Antonio AlGABA Isabel CHECA Cristóbal GARCIA Manuel reyes Department of Mathematics Faculty of Experimental Sciences

The Newton diagram and, in particular, the lowest-degree quasi-homogeneous terms of an analytic planar vector field allow us to determine the existence of characteristic orbits and separatrices of an isolated singular point. We give an easy algorithm for obtaining the local phase portrait near the origin of a bi-dimensional differential system and we provide several examples.

关键词： Monodromy separatrices phase portraits quasi-homogeneous vector field