Kinetics of Self-decomposition of Peroxydiphosphate in Aqueous Sulphuric Acid Medium

35-3

Kinetics of Oxidation of Acetaldehyde, Propionaldehyde & n-Butyraldehyde by Peroxydiphosphate

420-42

High performance thin-layer chromatography and in vitro cytotoxic studies on ethanol extract of Matricaria chamomilla L (Asteraceae) flowers

Purpose: To develop a high performance thin-layer chromatography (HPTLC procedure for quantitation of apigenin in ethanol extract of Matricaria chamomilla (Babunaj) flowers, and to evaluate the extract for in vitro cytotoxic effect on MCF-7 cell lines. Methods: Quantification of apigenin was carried out using a CAMAG TLC system. A combination of toluene, ethyl acetate and formic acid (4.5:3.5:0.2 v/v/v) was used as mobile phase, with densitometry detection at 336 nm. The HPTLC procedure was subjected to validation as per ICH guidelines. The cytotoxicity of the extract was assessed by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) assay. Results: A sharp apigenin band at Rf of 0.51 was obtained, and the content of apigenin in the extract was 0.062 % w/w. The detection limit (LOD) and quantification limit (LOQ) were 0.19 and 0.57 ng/band, respectively. MTT assay results indicate that M. chamomilla was cytotoxic to Michigan Cancer Foundation-7 (MCF-7) cells, with half-maximal concentration (IC50) of 74 µg/mL. Conclusion: The developed HPTLC method is linear, precise, accurate and specific for the determination of apigenin. M. chamomilla exerts cytotoxic effect on MCF-7 cell line via induction of apoptosis

Optimization of antireflection coating design using pc1d simulation for c − si solar cell application

Minimizing the photon losses by depositing an anti-reflection layer can increase the conversion efficiency of the solar cells. In this paper, the impact of anti-reflection coating (ARC) for enhancing the efficiency of silicon solar cells is presented. Initially, the refractive indices and reflectance of various ARC materials were computed numerically using the OPAL2 calculator. After which, the reflectance of SiO2, TiO2, SiNx with different refractive indices (n) were used for analyzing the performance of a silicon solar cells coated with these materials using PC1D simulator. SiNx and TiO2 as single-layer anti-reflection coating (SLARC) yielded a short circuit current density (Jsc ) of 38.4 mA/cm2 and 38.09 mA/cm2 respectively. Highest efficiency of 20.7% was obtained for the SiNx ARC layer with n = 2.15. With Double-layer anti-reflection coating (DLARC), the Jsc improved by ∼0.5 mA/cm2 for SiO2 /SiNx layer and hence the efficiency by 0.3%. Blue loss reduces significantly for the DLARC compared with SLARC and hence increase in Jsc by 1 mA/cm2 is observed. The Jsc values obtained is in good agreement with the reflectance values of the ARC layers. The solar cell with DLARC obtained from the study showed that improved conversion efficiency of 21.1% is obtained. Finally, it is essential to understand that the key parameters identified in this simulation study concerning the DLARC fabrication will make experimental validation faster and cheaper

A highly efficient green synthesis of 1, 8-dioxo-octahydroxanthenes

SmCl3 (20 mol%) has been used as an efficient catalyst for reaction between aromatic aldehydes and 5,5-dimethyl-1,3-cyclohexanedione at 120°C to give 1,8-dioxo-octahydroxanthene derivatives in high yield. The same reaction in water, at room temperature gave only the open chain analogue of 1,8-dioxo-octahydroxanthene. Use of eco-friendly green Lewis acid, readily available catalyst and easy isolation of the product makes this a convenient method for the synthesis of either of the products

Restricted Morphological and Behavioral Abnormalities following Ablation of β-Actin in the Brain

The local translation of β-actin is one mechanism proposed to regulate spatially-restricted actin polymerization crucial for nearly all aspects of neuronal development and function. However, the physiological significance of localized β-actin translation in neurons has not yet been demonstrated in vivo. To investigate the role of β-actin in the mammalian central nervous system (CNS), we characterized brain structure and function in a CNS-specific β-actin knock-out mouse (CNS-ActbKO). β-actin was rapidly ablated in the embryonic mouse brain, but total actin levels were maintained through upregulation of other actin isoforms during development. CNS-ActbKO mice exhibited partial perinatal lethality while survivors presented with surprisingly restricted histological abnormalities localized to the hippocampus and cerebellum. These tissue morphology defects correlated with profound hyperactivity as well as cognitive and maternal behavior impairments. Finally, we also identified localized defects in axonal crossing of the corpus callosum in CNS-ActbKO mice. These restricted defects occurred despite the fact that primary neurons lacking β-actin in culture were morphologically normal. Altogether, we identified novel roles for β-actin in promoting complex CNS tissue architecture while also demonstrating that distinct functions for the ubiquitously expressed β-actin are surprisingly restricted in vivo

Mechanisms and in vivo functions of contact inhibition of locomotion

Contact inhibition of locomotion (CIL) is a process whereby a cell ceases motility or changes its trajectory upon collision with another cell. CIL was initially characterized more than half a century ago and became a widely studied model system to understand how cells migrate and dynamically interact. Although CIL fell from interest for several decades, the scientific community has recently rediscovered this process. We are now beginning to understand the precise steps of this complex behaviour and to elucidate its regulatory components, including receptors, polarity proteins and cytoskeletal elements. Furthermore, this process is no longer just in vitro phenomenology; we now know from several different in vivo models that CIL is essential for embryogenesis and in governing behaviours such as cell dispersion, boundary formation and collective cell migration. In addition, changes in CIL responses have been associated with other physiological processes, such as cancer cell dissemination during metastasis

A mechanically active heterotypic E-cadherin/N-cadherin adhesion enables fibroblasts to drive cancer cell invasion

Cancer-associated fibroblasts (CAFs) promote tumour invasion and metastasis. We show that CAFs exert a physical force on cancer cells that enables their collective invasion. Force transmission is mediated by a heterophilic adhesion involving N-cadherin at the CAF membrane and E-cadherin at the cancer cell membrane. This adhesion is mechanically active; when subjected to force it triggers β-catenin recruitment and adhesion reinforcement dependent on α-catenin/vinculin interaction. Impairment of E-cadherin/N-cadherin adhesion abrogates the ability of CAFs to guide collective cell migration and blocks cancer cell invasion. N-cadherin also mediates repolarization of the CAFs away from the cancer cells. In parallel, nectins and afadin are recruited to the cancer cell/CAF interface and CAF repolarization is afadin dependent. Heterotypic junctions between CAFs and cancer cells are observed in patient-derived material. Together, our findings show that a mechanically active heterophilic adhesion between CAFs and cancer cells enables cooperative tumour invasion

A possible role for phototrophic sulphur bacteria in the promotion of anaerobic metal corrosion

Bacteria associated with the biological sulphur cycle play a particularly dominant role in the process of metallic corrosion. This is largely due to the ubiquitous presence of these bacteria in natural environments1,2. Unsurprisingly, sulphatereducing bacteria have been the main highlight in numerous bio-corrosion investigations. A vast number of mechanisms3–8 have been proposed in the literature to explain the rather multifarious process of anaerobic corrosion. The deterioration of iron and concrete by aerobic sulphur bacteria (thiobacilli) is more straightforward. These bacteria oxidize sulphur and/or sulphide to sulphuric acid9