Growth and some surface characterization of tin Sulphide (SnS) thin film by two-electrode cell arrangement for photo absorption

This study presented deposition of tin sulphide (SnS) thin film using a two-electrode electrochemical cell arrangement. The bath electrolyte comprised tin sulphate (SnSO4 ), hydrated sodium thiosulphate (Na2S2O3∙5H2O) and sulphuric acid (H2SO4 ). The acid was used to adjust the pH of the bath. The deposited film was characterised using Surface Profilometer, X-Ray Diffractometer (XRD), Uv-Visible Spectrophotometer and four point probe technique. Surface profiling revealed that the film is continuous with thickness of about 60 nm. The XRD result showed that the film has orthorhombic crystal structure. Film's crystallite size was estimated as 0.61 nm and interplanar spacing as 0.29 nm. The Uv-visible Spectrophotometer result reveals that, the film has good absorbance but poor reflectance and transmittance in the visible light region. The film has direct allowed transition with energy band gap of 1.69 eV. Values of surface resistivity and conductivity were deduced from data obtained from Four-point probe studies as 5.12 x 10-4Ω-cm and 1.96 x 103Ω-1cm-1 respectively. The I-V characteristics curve of ITO/SnS/Ag structure is linear indicating an Ohmic contact between the substrate electrode and the deposited layer. It can therefore be suggested that the film can allow pathway for photoabsorption and also aid charge transfer in photovoltaic process. Keywords: tin sulphide, orthorhombic, electrochemical deposition, characterization, photovoltaic and surface resistivity.

A Loss of Nuclear—Cytoskeletal Interactions in Vascular Smooth Muscle Cell Differentiation Induced by a Micro-Grooved Collagen Substrate Enabling the Modeling of an In Vivo Cell Arrangement

Vascular smooth muscle cells (VSMCs) remodel vascular walls actively owing to mechanical cues and dedifferentiate to the synthetic phenotype from contractile phenotype in pathological conditions. It is crucial to clarify the mechanisms behind the VSMC phenotypic transition for elucidating their role in the vascular adaptation and repair and for designing engineered tissues. We recently developed novel micro-grooved collagen substrates with “wavy wrinkle” grooves to induce cell–substrate adhesion, morphological polarization, and a tissue-like cell arrangement with cytoskeletal rearrangements similar to those in vascular tissue in vivo. We found that cultivation with this micro-grooved collagen significantly induced VSMC contractile differentiation. Nonetheless, the detailed mechanism underlying the promotion of such VSMC differentiation by micro-grooved collagen has not been clarified yet. Here, we investigated the detailed mechanism of the cell arrangement into a tissue and contractile-differentiation improvement by our micro-grooved collagen substrates in terms of nuclear–cytoskeletal interactions that possibly affect the nuclear mechanotransduction involved in the activation of transcription factors. We found that VSMCs on micro-grooved collagen manifested significant cell arrangement into a tissue and nucleus slimming with a volume reduction in response to the remodeling of the actin cytoskeleton, with consequent inhibition of nuclear shuttling of a transcriptional coactivator, Yes-associated protein (YAP), and improved contractile differentiation. Furthermore, VSMC nuclei rarely deformed during macroscopic cell stretching and featured a loss of nesprin-1–mediated nuclear–cytoskeletal interactions. These results indicate that our micro-grooved collagen induces a cell alignment mimicking in vivo VSMC tissue and promotes contractile differentiation. In such processes of contractile differentiation, mechanical interaction between the nucleus and actin cytoskeleton may diminish to prevent a nuclear disturbance from the excess mechanical stress that might be essential for maintaining vascular functions.

The extra-embryonic space is a geometric constraint regulating cell arrangement in nematodes

In multicellular systems, cells communicate with adjacent cells to decide their positions and fates. Cellular arrangement in space is thus important for development. Orientation of cell division, cell-cell interaction (i.e., attraction and repulsion), and geometrical constraints are the three major factors that define cell arrangement. Here we found that the amount and location of extra-embryonic space (ES), the empty space within the eggshell not occupied by embryonic cells, are critical to define cell arrangement in the 4-cell stage embryo of nematodes. This discovery was motivated by observations of a T-reversed-type arrangement, which was not explained by a model assuming simplified shapes of the eggshell, in our previous experiments. In this study, we incorporated the precise shape of the C. elegans eggshell in our newly developed multicellular morphology model based on the phase-field method. The new model succeeded in reproducing the T-reverse arrangement, demonstrating the importance of the precise shape of the eggshell. Further analyses revealed that the amount and location of ES is critical to develop various cell arrangements. Overall, our analyses characterized the roles of new geometrical contributors to cell arrangements, which should be considered for any multicellular system.

Validación y análisis de eficiencia en la producción de agua mediante la implementación de celdas Peltier

At present, drought seasons are longer as a result of global warming, which has generated scarcity and rationing of water, these conditions become the main problem in towns far from urban areas and with little infrastructure. Mexico, with 653 aquifers throughout its territory, 106 are overexploited due to agricultural, mining, industrial and urban activities, which projects a possible depletion and contamination of its vital liquid to the country. For this reason, in order to contribute to a solution to the problem of water scarcity, when applying a control system to the technology used by Peltier cells, a moderate flow of water is generated, since it condenses the particles of water suspended in the air. In this way, a prototype was developed in which a Peltier cell arrangement is implemented to obtain as much water as possible under environmental factors, such as humidity and temperature, as well as an analysis of efficiency, cost and viability with a commercial generator system of water with similar capacities.