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A critique of supernova data analysis in cosmology

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Research in Astronomy and Astrophysics 2010年第12期10卷 1195-1198页

作者： Ram Gopal Vishwakarma Jayant V. Narlikar unidad académica de Matemáticas Universidad Autónoma de Zacatecas Inter-University Centre for Astronomy and Astrophysics

Observational astronomy has shown significant growth over the last decade and has made important contributions to cosmology. A major paradigm shift in cosmology was brought about by observations of Type Ia supernovae. The notion that the universe is accelerating has led to several theoretical challenges. Unfortunately, although high-quality supernovae data-sets are being produced, their statistical anal- ysis leaves much to be desired. Instead of using the data to directly test the model, several studies seem to concentrate on assuming the model to be correct and limiting themselves to estimating model parameters and internal errors. As shown here, the important purpose of testing a cosmological theory is thereby vitiated.

关键词： cosmology: observations -- supernovae Ia: general

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Proteomics for discovery of candidate colorectal cancer biomarkers

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World Journal of Gastroenterology 2014年第14期20卷 3804-3824页

作者： Paula lvarez-Chaver Olalla Otero-Estévez María Páez de la Cadena Francisco J Rodríguez-Berrocal Vicenta S Martínez-Zorzano unidad de Proteómica Servicio de Determinación EstructuralProteómica y GenómicaCentro de Apoyo Científico y Tecnológico a la InvestigaciónUniversidad de VigoCampus As Lagoas-Marcosende área de Bioquímica y Biología Molecular Departamento de BioquímicaGenética e InmunologíaFacultad de BiologíaUniversidad de VigoCampus As Lagoas-Marcosende

Colorectal cancer(CRC)is the second most common cause of cancer-related deaths in Europe and other Western countries,mainly due to the lack of wellvalidated clinically useful biomarkers with enough sensitivity and specificity to detect this disease at early *** it is well known that the pathogenesis of CRC is a progressive accumulation of mutations in multiple genes,much less is known at the proteome ***,in the last years many proteomic studies have been conducted to find new candidate protein biomarkers for diagnosis,prognosis and as therapeutic targets for this malignancy,as well as to elucidate the molecular mechanisms of colorectal *** important advantage of the proteomic approaches is the capacity to look for multiple differentially expressed proteins in a single *** review provides an overview of the recent reports describing the different proteomic tools used for the discovery of new protein markers for CRC such as two-dimensional electrophoresis methods,quantitative mass spectrometry-based techniques or protein ***,we will also focus on the diverse biological samples used for CRC biomarker discovery such as tissue,serum and faeces,besides cell lines and murine models,discussing their advantages and disadvantages,and summarize the most frequently identified candidate CRC markers.

关键词： Colorectal cancer Serum Tissue Proteins Biomarkers Proteomics Protein identification Mass spectrometry

Enantioselective Synthesis,(Chir)optical Properties,and Postsynthetic Functionalization of Furan-Containing Oxa[5]-,Oxa[6]-,and Dioxa[6]helicenes

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CCS Chemistry 2024年第10期6卷 2439-2451页

作者： Wei Fu Valentina Pelliccioli Raquel Casares-López Juan M.Cuerva Martin Simon Christopher Golz Manuel Alcarazo Institut für Organische und Biomolekulare Chemie Georg-August-Universität Göttingen37077 Göttingen departamento de química Orgánica Universidad de GranadaUnidad de Excelencia Química Aplicada a Biomedicina y MedioambienteE-18071 Granada

An expedient synthesis of a series of configurationally stable oxa[5]helicenes,oxa[6]helicenes,and dioxa[6]helicenes has been developed using an intramolecular,highly enantioselective,Au-catalyzed,alkyne hydroarylation *** absolute configuration of the newly prepared structures has been established by crystallography,their inversion barriers have been determined theoretically and experimentally,and their chiroptical properties have been *** of these data with those reported for thia-or carbohelicenes sharing an otherwise identical helical framework enables the establishment of comprehensive correlations between the nature of the embedded(hetero)atom(s)and the magnitude of these *** studies on the postsynthetic functionalization of the oxahelicenes obtained are also ***,siteselective bromination at the 15-position in oxa[5]helicene 5d allows its subsequent manipulation into pyridine-containing aza-oxa[7]helicene 13d;while the two termini of oxa[6]helicene 7d have been intramolecularly cyclised into the pleiadeno[1,12,11-bcde]benzofuran derivative 15d by acidic *** transformations take place without erosion of the enantiopurity.

关键词： Au-catalysis enantioselective synthesis oxa[n]helicenes racemization dynamics postsynthetic functionalization

Chromomagnetic dipole moments of light quarks in the bestest little Higgs model

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Chinese Physics C 2024年第10期48卷 125-136页

作者： T.Cisneros-Pérez E.Cruz-Albaro A.Y.Ojeda-Castañeda S.E.Solís-Núñez unidad académica de Ciencias químicas Universidad Autónoma de ZacatecasApartado Postal C-58598060 ZacatecasMexico Facultad de Física Universidad Autónoma de ZacatecasApartado Postal C-58098060 ZacatecasMexico

In this study,we investigated the anomalous Chromomagnetic Dipole Moment(CMDM),denoted as μ_(q)^(BLHM),of light quarks q=(u,c,d,s,b) within the framework of the Bestest Little Higgs Model(BLHM)as an extension of the Standard Model(SM).Our investigation encompassed novel interactions among the light quarks,heavy quark B,and heavy bosons (W'^(±),H^(±),φ^(±),η^(±))incorporating the extended Cabibbo-Kobayashi-Maskawa(CKM)matrix characteristic of the *** thoroughly explored the permissible parameter space,yielding a spectrum of CMDM values ranging from 10^(-10) to 10^(-3).

关键词： beyond standard model flavor physics chromomagnetic dipole light quarks

A Numerical Study Comparing the Effect on Residual Stresses of Two Different Types of Projectiles During Shot Peening

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Computers, Materials & Continua 2016年第3期51卷 203-215页

作者： J.Solórzano-López F.A.García-Pastor Angélica Flores-Luna UNAM Facultad de QuímicaCiudad de MéxicoMéxico Cinvestav unidad Saltillo CoahuilaMéxico TecNM Instituto Tecnológico de Tláhuac IIICiudad de MéxicoMéxico

Shot peening is a widely used technique to improve fatigue life in metallic *** processing technique introduces a subsurface compressive residual stress field through a plastic deformation of the surface caused by the impact of a large number of high-speed *** are a number of parameters that affect the residual stress field depth and *** effects of the impact angle,shot speed and shot geometry are currently being *** particular,substituting spherical cast shots by cylindrical cut wire shots is an attractive option,especially in terms of *** effect of shot geometry on residual stresses,however,needs to be further *** industrial-scale experimentation is costly and cumbersome,mathematical modeling offers a convenient alternative to carry out this type of *** present work shows a comparison between the residual stresses generated by the impact of spherical and cylindrical projectiles on a steel *** threedimensional model was developed using ABAquS finite element commercial software(Release 6.12,Dassault Systémes,France).The results show that cylindrical shots generate residual stress fields t hat a re higher in magnitude than t hose generated by a spherical ***,the residual stress field of cylindrical shots impacting the surface at an oblique angle shows an important degree of *** effect is not found when spherical shots impact the surface at the same oblique angle.

关键词： Shot Peening Finite element method Residual Stresses

The potential of starch-chitosan blends with poloxamer for the preparation of microparticles by spray-drying

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Particuology 2024年第6期89卷 1-10页

作者： Juan Enrique Barranco-García Carolina Caicedo Enrique Javier Jiménez-Regalado Carlos Espinoza-González Graciela Morales Rocio Yaneli Aguirre-Loredo Abril Fonseca-García Tecnológico Nacional de México/Instituto Tecnológico de Oaxaca Departamento de Química y BioquímicaAvenida Ing.Víctor Bravo Ahuja No.125Esquina Calzada Tecnológico68030OaxacaMexico Faculty of Engineering Unidad Central del Valle del Cauca(UCEVA)Carrera 17a 48-144763022TuluáColombia Centro de Investigación en química Aplicada(CIQA) Blvd.Enrique Reyna Hermosillo 14025294SaltilloCoahuilaMexico Investigadoras por México CONAHCYT-CIQA Av.Insurgentes Sur 1562Col.Crédito Constructor03940Alcaldía Benito JuárezCDMXMexico

Using biopolymers as wall materials in spray drying poses challenges,particularly in attaining flowability and thermal stability among their physicochemical *** paper addresses these challenges by preparing microparticles using a blend of starch–chitosan and a poloxamer,commercially named Pluronic®*** aimed to elucidate the effects of varying poloxamer concentrations on the resulting particles through the spray drying *** with a poloxamer concentration of 3%(w/v)demonstrated a notably higher yield,especially when compared to those with 0%and 1%*** with 3%and 5%(w/v)poloxamer displayed a narrower particle size distribution,with the 3%blend showing a superior yield attributed to arrangements of blend components that improve flowability.X-ray diffraction analysis showcased the characteristic peaks of A-type starch form,with shifts suggesting enhanced interactions between *** with increased poloxamer content showed elevated thermal degradation temperatures,with the 3%blend registering a significant rise,opening avenues for encapsulating heat-sensitive *** study primarily focuses on the preparation and basic characterization of *** underscores the potential of blends with optimal poloxamer concentrations in microencapsulation,emphasizing further research to harness their capabilities thoroughly.

关键词： Biopolymer Starch Chitosan Pluronic®F127 Microparticles Spray drying

Contrasting initial events of localized corrosion on surfaces of 2219-T42 and 6061-T6 aluminum alloys exposed in Caribbean seawater

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Transactions of Nonferrous Metals Society of China 2019年第1期29卷 34-42页

作者： Gloria ACOSTA Lucien VELEVA Juan Luis LóPEZ D.A.LóPEZ-SAURI Applied Physics department Research Center for Advanced Studies (CINVESTAV) Unidad Mérida Tecnológico Nacional de México Instituto Tecnológico de Mérida Departamento de Química y Bioquímica

Aluminum alloy samples, 6061-T6 and 2219-T42, were exposed to Caribbean seawater for 90 d. The fluctuations of open circuit potential, considered as electrochemical noise (EN), were used to characterize and compare initial pitting events, which appeared on their surfaces. EN analysis was carried out using the power spectral density (PSD) vs frequency. The decrease of the β exponent in PSD graphs indicated a release of spontaneous energy with the progress of pit formation in seawater. The fluctuations were associated with the breakdown and formation of new corrosion layers. The values of β exponent in PSD graphs suggest that corrosion process of AA2219-T42 alloy occurs as a persistent non-stationary process, the dynamics of which is controlled by fractional Brownian motion (fBm), while on AA6061-T6 alloy the corrosion process was dominated by stationary and weakly persistent features, with the contribution of fractional Gaussian noise (fGn). After the exposure in seawater, SEM-EDX analysis revealed insoluble intermetallic particles on the alloys, rich in Cu or Fe and irregularly distributed. The preferential dissolution of Mg and Al occurs from the S-phase (Al2CuMg) of AA2219-T42 alloy.

关键词： aluminum alloy corrosion electrochemical noise intermetallic particles seawater

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On the Differential Polynomial of a Graph

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Acta Mathematica Sinica,English Series 2019年第3期35卷 338-354页

作者： Ludwin A.BASILIO-HERNáNdeZ Walter CARBALLOSA Jesús LEA?OS José M.SIGARRETA unidad académica de Matemáticas Universidad Autónoma de Zacatecas Calzada Solidaridad entronque Paseo a la Bufa department of Mathematics and Statistics Florida International University department of Mathematics Miami Dade College Facultad de Matemáticas Universidad Autónoma de Guerrero

We introduce the differential polynomial of a graph. The differential polynomial of a graph G of order n is the polynomial B(G; x) :=∑?(G)k=-nB_k(G) x^(n+k), where B_k(G) denotes the number of vertex subsets of G with differential equal to k. We state some properties of B(G;x) and its *** particular, we compute the differential polynomial for complete, empty, path, cycle, wheel and double star graphs. We also establish some relationships between B(G; x) and the differential polynomials of graphs which result by removing, adding, and subdividing an edge from G.

关键词： Graph polynomial differential of a graph

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Hydrothermal synthesis of pyrrhotite(Fex-1S) nanoplates and their antibacterial, cytotoxic activity study

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Progress in Natural Science:Materials International 2018年第4期28卷 447-455页

作者： Liliana Argueta-Figueroa Nayely Torres-Gómez René García-Contreras A.R.Vilchis-Nestor O.Martínez-Alvarez L.S.Acosta-Torres M.C.Arenas-Arrocena Laboratorio de Investigación Interdisciplinaria área de Nanoestructuras y Biomateriales Escuela Nacional de Estudios Superiores Unidad León Universidad Nacional Autónoma de México Centro Conjunto de Investigación en química Sustentable (CCIQS) UEAMex-UNAM departamento de Ingeniería en Energía Universidad Politécnica de Guanajuato

The aim of this study was to synthesize and characterize Fex-1S 2D-nanostructures with pyrrhotite phase,as well as to explore their biological(antibacterial and cytotoxic)properties,namely the expression of reactive oxygen species(ROS)in the exposure of cells and *** on hydrothermal synthesis,the characterization of asprepared 2D-nanostructures was performed by XRD,SEM,EDS,and TEM,in which the single-crystalline pyrrhotite phased Fex-1S nanoplate morphology was *** antibacterial activities of Fex-1S nanoplates against human pathogenic strains such as Staphylococcus aureus,Escherichia coli,and Enterococcus faecalis were *** inhibitory concentration(MIC)and minimum bactericidal concentration(MBC)were determined following the broth microdilution *** and expression of intracellular ROS of pyrrhotite nanoplates on Human Gingival Fibroblast(HGF),Human Pulp Cells(HPC)and Human Osteoblast(HBC)were *** viability was determined by the MTT *** experiments were performed of three independent experiments and data were analyzed by Kruskal-Wallis and Mann-Whitney tests,also Pearson′s Correlation was *** nanoplates exhibited good bactericidal *** types of cells tested showed slight *** was found that intracellular ROS is produced when cells and bacteria tested are exposed to pyrrhotite nanoplates in presence of both air and peroxide *** production levels were higher in the bacteria than the cells exposed to these nanoplates.

关键词： Hydrothermal synthesis Iron sulfide nanoplates Minimal inhibitory concentration Antibacterial effect Cytotoxicity assay