Growth and properties of lead iodide thin films by spin coating

In this study, lead iodide (PbI2) thin films were deposited on glass substrates by spin coating a solution of 0.2 M PbI2 dissolved in dimethylformamide, varying the deposition time and the spin speed. The thickness of the thin films decreased with increase in spin speed and deposition time, as examined by profilometry measurements. The structure, morphology, optical and electrical properties of the thin films were analysed using various techniques. X-ray diffraction patterns revealed that the thin films possessed hexagonal structures. The thin films were grown highly oriented to [001] direction of the hexagonal lattice. Raman peaks detected at 96 and 136 cm−1 were corresponding to the characteristic vibration modes of PbI2. The X-ray photoelectron spectroscopy detected the presence of Pb and I with core level binding energies corresponding to that in PbI2. Atomic force microcopy showed smooth and compact morphology of the thin films. From UV–Vis transmittance and reflectance spectral analysis, the bandgap of the thin films ∼2.3 eV was evaluated. The dark conductivity of the thin films was computed and the value decreased as the deposition time and spin speed increase

“Y vienen ofreciéndote de todo, hasta despensas a cambio del voto.” El clientelismo político y la exclusión social en el ámbito rural en Zacatecas

El fenómeno del clientelismo político como objeto de estudio, guarda una conexión simétrica con la desigualdad económica y social, los procesos de exclusión, la democracia y la pobreza. De acuerdo con Ugalde citado en Mata (2019), el clientelismo político es la entrega de prebendas, cargos públicos y recursos por parte de políticos y candidatos a cambio de recibir apoyo político y/o económico; puede generase de dos formas: 1) que sea voluntario —mediante la compra del voto— o involuntario —por la vía de mecanismos de coacción—. Asimismo, Mata (2019) agrega que, en México el clientelismo político se refiere principalmente “a la compra, coacción y movilización del voto, también se suma el condicionamiento de los programas sociales y de concesiones o licencias a cambio del sufragio por un partido” (p.907). El clientelismo político está presente en muchos países, pero con diferentes matices o formas de operar, asimismo, está contextualizado en el ámbito rural como urbano y es durante los últimos años que habido un auge del problema en los países latinoamericanos. Aquí se trata de aproximar, a un entorno cercano a los estudios de América Latina y particularmente en México. En el cual los mecanismos del clientelismo han formado procesos de clientela y jerarquías propias que emanan de las características de la población excluida, primordialmente, en este caso se hace un acercamiento al ámbito rural. Para contextualizar el fenómeno del clientelismo político, en los siguientes párrafos se intentará relacionar éste con la exclusión social y en efecto la existencia de ambos en las localidades de Ex-Hacienda de Gruñidora e Ignacio Allende, ubicadas en el municipio de Mazapil

Development and evaluation of a nanofiber membrane in vitro as a therapeutic alternative for the post treatment in breast cancer cell in a murine model

Worldwide female breast cancer is the most commonly diagnosed cancer, with an estimated 2.3 million new cases in 2020, reason for the need of targeted therapies that can maximize treatment success and minimize toxicity. Nanoparticles of gold (AuNps) exhibit cytotoxic properties against certain types of cancer cell lines. Nanofibers have been use in the drug delivery systems due to its degradability and high surface area. We proposed a membrane with nanometric fibers using polivinilic alcohol (PVA) and chitosan (Qts) loaded with AuNps and Doxorubicin (Doxo) with the purpose of diminish tumor regression. PVA-Qts membrane was develop with electrospinning, the injection, voltage, distance and relative humidity parameters were standardized and it were characterized by Microscopic Atomic Force. The cytotoxicity with a median lethal dose (DL50) in two cell lines, breast adenocarcinoma murine (4T1) and murine fibroblast (NiH3T3) as a healthy control were evaluated. AuNps had a size of 3 nanometers (nm) with a Z potential of 13.2 mVolts and a DL50 of 75 µM in the cell line 4T1. Doxo was decrease in 95% with a final concentration of 0.03 mg/cm2. Both doses were loaded in the PVA-Qts solution. PVA-Qts-Doxo and PVA-Qts-AuNps-Doxo decrease the viability in 4T1 in 24 hours with a 15%, 72 hours with a 28%, the first with 60% and the latter with 82%. PVA-Qts-Doxo and PVA-Qts-AuNps-Doxo in NiH3T3 diminish incrementing with the time reaching a 40% in 120 hours. Finally, The viability for 4T1 cultured on PVA-Qts-Doxo was minor than in NiH3T3. The amount of Doxo in the membrane synthetized was 95% less than the employ doses, demonstrating that the fiber improves the delivery of the chemotherapeutic in a palatine time

Long-term influence of chitin concentration on the resistance of cement pastes determined by atomic force microscopy

The presence of sulfates potentialize damage on cementbased materials, leading to structural failures. Therefore, structures must be designed to compensate for this effect. The mechanical properties of cement–chitin mixtures are investigated with different percentages of chitin (0.5, 1.3, and 2.1 wt.%) and aging of composite in a joint nanoscopic- and macroscopic-scale by experimental study. The objective is to increase the durability of concrete elements at coastal aquifers where concrete structures are in constant exposure to sulfate ions, chloride ions among others. Tapping mode AFM was used to characterize the surface structure and roughness of the cement pastes. To verify the chitin addition and the formation of sulfate-based aggregates Raman and IR spectra were recorded and are presented in this work. Then, force spectroscopy was used to obtain the nanomechanical properties at three different exposure times (1 day, 6 months, and 1 year) into water or a SO4 2 environment. Macroscopic parameters (e.g., compression strength of cylindrical probes) were assessed for comparison following standard guidelines. The results show a decrease of its mechanical properties as a function of the polymer concentration but more importantly, they correlate the elasticity and adhesion at the nanoscale with the behavior of the bulk material

Isolation ofBdellovibriosp. from soil samples in Mexico and their potential applications in control of pathogens

In this study, two strains of Bdellovibrio were isolated from soil samples using the culture-dependent technique and two members of the family Enterobacteriaceae (Klebsiella sp. and Salmonella sp.) as prey. The Bdellovibrio strains were bacteriolytic, plaque-forming, and highly motile gram-negative bacteria. We identified and confirmed the Bdellovibrio strains using microscopy, PCR amplification, and sequencing of the 16S rRNA gene. They were observed to be different strains based on hit locus and prey range analyses. Here, the first report on Bdellovibrio strains isolated from soil in Mexico corroborates earlier report indicating that populations of Bdellovibrio found in soil are heterogeneous thereby the need to identify the various strains

Gelatin-methacryloyl hydrogels containing turnip mosaic virus for fabrication of nanostructured materials for tissue engineering

16 Pág.Current tissue engineering techniques frequently rely on hydrogels to support cell growth, as these materials strongly mimic the extracellular matrix. However, hydrogels often need ad hoc customization to generate specific tissue constructs. One popular strategy for hydrogel functionalization is to add nanoparticles to them. Here, we present a plant viral nanoparticle the turnip mosaic virus (TuMV), as a promising additive for gelatin methacryloyl (GelMA) hydrogels for the engineering of mammalian tissues. TuMV is a flexuous, elongated, tubular protein nanoparticle (700-750 nm long and 12-15 nm wide) and is incapable of infecting mammalian cells. These flexuous nanoparticles spontaneously form entangled nanomeshes in aqueous environments, and we hypothesized that this nanomesh structure could serve as a nanoscaffold for cells. Human fibroblasts loaded into GelMA-TuMV hydrogels exhibited similar metabolic activity to that of cells loaded in pristine GelMA hydrogels. However, cells cultured in GelMA-TuMV formed clusters and assumed an elongated morphology in contrast to the homogeneous and confluent cultures seen on GelMA surfaces, suggesting that the nanoscaffold material per se did not favor cell adhesion. We also covalently conjugated TuMV particles with epidermal growth factor (EGF) using a straightforward reaction scheme based on a Staudinger reaction. BJ cells cultured on the functionalized scaffolds increased their confluency by approximately 30% compared to growth with unconjugated EGF. We also provide examples of the use of GelMA-TuMV hydrogels in different biofabrication scenarios, include casting, flow-based-manufacture of filaments, and bioprinting. We envision TuMV as a versatile nanobiomaterial that can be useful for tissue engineering.EV-L, AIF-S, MJ-LZ, and JAT-N acknowledge funding from scholarships provided by CONACyT (Consejo Nacional de Ciencia y Tecnología, México). EV-L acknowledges the Nuevo Leon Institute for Innovation and Technology Transference for a PhD student grant (No. 459134, CVU 360539). GT-dS and MMA acknowledge the institutional funding received from Tecnológico de Monterrey (Grant 002EICIS01). MMA, GT-dS, and IG-G acknowledge funding provided by CONACyT (Consejo Nacional de Ciencia y Tecnología, México) through several grants (SNI 26048, SNI 256730, and SNI 313028). FP acknowledge the funding received from RTA 2015-00017 from INIA and EU Arimnet-2 Grant Agreement No. 618127. The CBGP was granted “Severo Ochoa” Distinctions of Excellence by the Spanish Ministry of Science and Innovation (SEV-2016-0672 and CEX 2020-000999-S)Peer reviewe

Production of He-4 and (4) in Pb-Pb collisions at root(NN)-N-S=2.76 TeV at the LHC

Results on the production of He-4 and (4) nuclei in Pb-Pb collisions at root(NN)-N-S = 2.76 TeV in the rapidity range vertical bar y vertical bar <1, using the ALICE detector, are presented in this paper. The rapidity densities corresponding to 0-10% central events are found to be dN/dy4(He) = (0.8 +/- 0.4 (stat) +/- 0.3 (syst)) x 10(-6) and dN/dy4 = (1.1 +/- 0.4 (stat) +/- 0.2 (syst)) x 10(-6), respectively. This is in agreement with the statistical thermal model expectation assuming the same chemical freeze-out temperature (T-chem = 156 MeV) as for light hadrons. The measured ratio of (4)/He-4 is 1.4 +/- 0.8 (stat) +/- 0.5 (syst). (C) 2018 Published by Elsevier B.V.Peer reviewe

Azimuthal anisotropy of charged jet production in root s(NN)=2.76 TeV Pb-Pb collisions

We present measurements of the azimuthal dependence of charged jet production in central and semi-central root s(NN) = 2.76 TeV Pb-Pb collisions with respect to the second harmonic event plane, quantified as nu(ch)(2) (jet). Jet finding is performed employing the anti-k(T) algorithm with a resolution parameter R = 0.2 using charged tracks from the ALICE tracking system. The contribution of the azimuthal anisotropy of the underlying event is taken into account event-by-event. The remaining (statistical) region-to-region fluctuations are removed on an ensemble basis by unfolding the jet spectra for different event plane orientations independently. Significant non-zero nu(ch)(2) (jet) is observed in semi-central collisions (30-50% centrality) for 20 <p(T)(ch) (jet) <90 GeV/c. The azimuthal dependence of the charged jet production is similar to the dependence observed for jets comprising both charged and neutral fragments, and compatible with measurements of the nu(2) of single charged particles at high p(T). Good agreement between the data and predictions from JEWEL, an event generator simulating parton shower evolution in the presence of a dense QCD medium, is found in semi-central collisions. (C) 2015 CERN for the benefit of the ALICE Collaboration. Published by Elsevier B.V. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).Peer reviewe

Forward-central two-particle correlations in p-Pb collisions at root s(NN)=5.02 TeV

Two-particle angular correlations between trigger particles in the forward pseudorapidity range (2.5 2GeV/c. (C) 2015 CERN for the benefit of the ALICE Collaboration. Published by Elsevier B. V.Peer reviewe

Event-shape engineering for inclusive spectra and elliptic flow in Pb-Pb collisions at root(NN)-N-S=2.76 TeV

Peer reviewe