Natural photosensitizers for dye sensitized solar cells

Dye-sensitized solar cells (DSSCs) were constructed by using the Lawsonia inermis leaves, Sumac/Rhus fruits, and Curcuma longa roots as natural sensitizers of anatase-based nanostructure TiO2 thin film Paint-coated on ITO conducting glass. The orange-red Lawsone, red purple anthocyanin and yellow Curcumin are the main components in the natural dyes obtained from these natural products. A blend of 50 wt% chitosan and 50 wt% polyethylene oxide (PEO) was used as a solid state thin film electrolyte. The polymer blend was complexed with ammonium iodide (NH4I) and some iodine crystals were added to the polymer–NH4I solution to provide I-/I3- redox couple. The ionic conductivity of the polymer electrolyte is 1.18x10-5 S cm-1 at room temperature. Structural and optical properties of the semiconductor thin films were characterized by X-ray diffractometer and UV-VIS spectrophotometer. The XRD shows nanocrystalline structures for TiO2 thin films (D=13nm). The photovoltaic properties of the cell have been studied and the best overall solar energy conversion efficiency of 1.75% was obtained, under AM 1.5 irradiation, with the red purple Sumac/Rhus extract, that showed a reasonable current density (Jsc = 0.93 mA/cm2)

Acetylation of C-terminal lysines modulates protein turnover and stability of Connexin-32

Background The gap junction protein, Connexin32 (Cx32), is expressed in various tissues including liver, exocrine pancreas, gastrointestinal epithelium, and the glia of the central and peripheral nervous system. Gap junction-mediated cell-cell communication and channel-independent processes of Cx32 contribute to the regulation of physiological and cellular activities such as glial differentiation, survival, and proliferation; maintenance of the hepatic epithelium; and axonal myelination. Mutations in Cx32 cause X-linked Charcot–Marie–Tooth disease (CMT1X), an inherited peripheral neuropathy. Several CMT1X causing mutations are found in the cytoplasmic domains of Cx32, a region implicated in the regulation of gap junction assembly, turnover and function. Here we investigate the roles of acetylation and ubiquitination in the C-terminus on Cx32 protein function. Cx32 protein turnover, ubiquitination, and response to deacetylase inhibitors were determined for wild-type and C-terminus lysine mutants using transiently transfected Neuro2A (N2a) cells. Results We report here that Cx32 is acetylated in transfected N2a cells and that inhibition of the histone deacetylase, HDAC6, results in an accumulation of Cx32. We identified five lysine acetylation targets in the C-terminus. Mutational analysis demonstrates that these lysines are involved in the regulation of Cx32 ubiquitination and turnover. While these lysines are not required for functional Cx32 mediated cell-cell communication, BrdU incorporation studies demonstrate that their relative acetylation state plays a channel-independent role in Cx32-mediated control of cell proliferation. Conclusion Taken together these results highlight the role of post translational modifications and lysines in the C-terminal tail of Cx32 in the fine-tuning of Cx32 protein stability and channel-independent functions

The effect of preventive, therapeutic and protective exercises on hippocampal memory mediators in stressed rats

Background: Exercise plays a significant role in learning and memory. The present study focuses on the hippocampal corticosterone (CORT), interleukin-1 beta(IL-1β), glucose, and brain derived neurotrophic factor (BDNF) levels in preventive, therapeutic, and protective exercises in stressful conditions. Methods: Forty male rats were randomly divided into four groups: the control group and the preventive, therapeutic, and protective exercise groups. The treadmill running was applied at a speed of 20-21m/min and a chronic stress of 6 hours/day for 21 days. Subsequently, the variables were measured in the hippocampus. Results: The findings revealed that the hippocampal CORT levels in the preventive exercise group had a significant enhancement compared to the control group. In the protective and particularly the therapeutic exercise groups, the hippocampal CORT levels declined. Furthermore, the hippocampal BDNF levels in the preventive and the therapeutic exercise groups indicated significantly decreased and increased, respectively, in comparison with the control group. In the preventive exercise group, however, the hippocampal glucose level turned out to be substantially higher than that in the control group. Conclusion: It appears that the therapeutic exercise group had the best exercise protocols for improving the hippocampal memory mediators in the stress conditions. By contrast, the preventive exercise group could not improve these mediators that had been altered by stress. It is suggested that exercise time, compared to stress, can be considered as a crucial factor in the responsiveness of memory mediators. � Penerbit Universiti Sains Malaysia, 2016

Substitutional doping of Cu in diamond: Mott physics with pp orbitals

Discovery of superconductivity in the impurity band formed by heavy doping of boron into diamond (C:B) as well as doping of boron into silicon (Si:B) has provided a rout for the possibility of new families of superconducting materials. Motivated by the special role played by copper atoms in high temperature superconducting materials where essentially Cu $d$ orbitals are responsible for a variety of correlation induced phases, in this paper we investigate the effect of substitutional doping of Cu into diamond. Our extensive first principle calculations averaged over various geometries based on density functional theory, indicates the formation of a mid-gap band, which mainly arises from the $t_{2g}$ and $4p$ states of Cu. For impurity concentrations of more than $\sim 1$2p$bands of neighboring carbon atoms can be ignored. Based on our detailed analysis, we suggest a two band model for the mid-gap states consisting of a quarter-filled hole like$t_{2g}$band, and a half-filled band of$4p$states. Increasing the concentration of the Cu impurity beyond$\sim 5%, completely closes the spectral gap of the host diamond.Comment: 5 figure