Search Results (6)

The 70% polyvinyl alcohol/30% polyvinyl pyrrolidone (PVA/PVP) polymer blends, with different weight ratios of tetrapropylammonium iodide (TPAI) or tetrahexylammonium iodide (THAI) salt, were prepared using dimethyl sulfoxide (DMSO) as a solvent. The X-ray diffraction technique was used to trace the crystalline nature of the formed blends. The SEM and EDS techniques were applied to figure out the morphology of the blends. The variation in the FTIR vibrational bands was used to investigate the chemical composition and the effect of different salt doping on the functional groups of the host blend. The influence of the salt type (TPAI or THAI) and its ratio on the linear and nonlinear optical parameters for the doped blends were investigated in detail. Absorbance and reflectance are highly enhanced in the UV region reaching a maximum for the blend with 24% TPAI or THAI; so, it can be employed as shielding materials for UVA and UVB types. The direct (5.1 eV) and indirect (4.8 eV) optical bandgaps were reduced continuously to (3.52, 3.63 eV) and (3.45, 3.51 eV) while increasing the content of TPAI or THAI, respectively. The blend doped with 24% wt TPAI exhibited the highest refractive index (around 3.5 in 400–800 nm). The DC conductivity is affected by the content and type of salt, its dispersion, and blend-salt interaction. The activation energies of different blends were obtained by applying the Arrhenius formula. Full article

Solvent evaporation and leakage of liquid electrolytes that restrict the practicality of dye-sensitized solar cells (DSSCs) motivate the quest for the development of stable and ionic conductive electrolyte. Gel polymer electrolyte (GPE) fits the criteria, but it still suffers from low efficiency due to insufficient segmental motion within the electrolytes. Therefore, incorporating metal oxide nanofiller is one of the approaches to enhance the performance of electrolytes due to the presence of cross-linking centers that can be coordinated with the polymer segments. In this research, polymer composite gel electrolytes (PCGEs) employing poly (vinyl butyral-co-vinyl alcohol-co-vinyl acetate) (P(VB-co-VA-co-VAc)) terpolymer as host polymer, tetrapropylammonium iodide (TPAI) as dopant salt, and copper oxide (CuO) nanoparticles as the nanofillers were produced. The CuO nanofillers were synthesized by sonochemical method and subsequently calcined at different temperatures (i.e., 200, 350, and 500 °C), denoted as CuO-200, CuO-350, and CuO-500, respectively. All CuO nanoparticles have different shapes and sizes that are connected in a chain which impact the amorphous phase and the roughness of the surface, proven by the structural and the morphological analyses. It was found that the PCGE consisting of CuO-350 exhibited the highest ionic conductivity of 2.54 mS cm⁻¹ and apparent diffusion coefficient of triiodide of 1.537 $\times$ 10⁻⁴ cm² s⁻¹. The enhancement in the electrochemical performance of the PCGEs is correlated with the change in shape (rod to sphere) and size of CuO particles which disrupted the structural order of the polymer chain, facilitating the redox couple transportation. Additionally, a DSSC was fabricated and achieved the highest power conversion efficiency of 7.05% with J_SC of 22.1 mA cm⁻², V_OC of 0.61 V, and FF of 52.4%. Full article

Pseudomonas viridiflava was originally reported as a bean pathogen, and subsequently as a wide-host range pathogen affecting numerous plants species. In addition, several authors have reported the epiphytic presence of this bacterium in “non-host plants”, which may act as reservoir of P. viridiflava and source of inoculum for crops. A new biotype of this bacterium, showing an atypical LOPAT profile, was found in Asturias, a Northern region of Spain, causing significant damage in beans, kiwifruit, lettuce, and Hebe. In order to investigate the involvement of weeds in bean disease, samples were collected from beans and weeds growing in the same fields. A total of 48 isolates of P. viridiflava were obtained, 39 from weeds and 9 from beans. 48% and 52% of them showed typical (L− O− P+ A− T+) and atypical (L+ O− P v A− T+) LOPAT profiles, and they displayed high biochemical diversity. Regarding virulence factors, the T-PAI and S-PAI pathogenicity islands were found in 29% and 70.8% of the isolates, 81.2% displayed pectinolytic activity on potato slices, and 59% of the weed isolates produced symptoms after inoculation on bean pods. A phylogenetic tree based on concatenated rpoD, gyrB, and gltA sequences separated the strains carrying S-PAI and T-PAI into different clusters, both containing isolates from beans and weeds, and pathogenic as well as non-pathogenic strains. Closely related strains were found in the two hosts, and more than half of the weed isolates proved to be pathogenic in beans. This is consistent with the role of weeds as a reservoir and source of inoculum for bean infection. Detection of P. viridiflava in weeds throughout the year further supports these roles. Full article

The progression of nonalcoholic fatty liver disease (NAFLD) to nonalcoholic steatohepatitis (NASH) is linked to systemic inflammation. Currently, two of the aspects that need further investigation are diagnosis and treatment of NASH. In this sense, the aim of this study was to assess the relationship between circulating levels of cytokines, hepatic expression of toll-like receptors (TLRs), and degrees of NAFLD, and to investigate whether these levels could serve as noninvasive biomarkers of NASH. The present study assessed plasma levels of cytokines in 29 normal-weight women and 82 women with morbid obesity (MO) (subclassified: normal liver (n = 29), simple steatosis (n = 32), and NASH (n = 21)). We used enzyme-linked immunosorbent assays (ELISAs) to quantify cytokine and TLR4 levels and RTqPCR to assess TLRs hepatic expression. IL-1β, IL-8, IL-10, TNF-α, tPAI-1, and MCP-1 levels were increased, and adiponectin levels were decreased in women with MO. IL-8 was significantly higher in MO with NASH than in NL. To sum up, high levels of IL-8 were associated with the diagnosis of NASH in a cohort of women with morbid obesity. Moreover, a positive correlation between TLR2 hepatic expression and IL-8 circulating levels was found. Full article

This work is a pioneer attempt to fabricate quasi-solid dye-sensitized solar cell (QSDDSC) based on organosoluble starch derivative. Rheological characterizations of the PhSt-HEC blend based gels exhibited viscoelastic properties favorable for electrolyte fabrication. From amplitude sweep and tack test analyses, it was evident that the inclusion of LiI improved the rigidity and tack property of the gels. On the other hand, the opposite was true for TPAI based gels, which resulted in less rigid and tacky electrolytes. The crystallinity of the gels was found to decline with increasing amount of salt in both systems. The highest photoconversion efficiency of 3.94% was recorded upon addition of 12.5 wt % TPAI and this value is one of the highest DSSC performance recorded for starch based electrolytes. From electrochemical impedance spectroscopy (EIS), it is deduced that the steric hindrance imposed by bulky cations aids in hindering recombination between photoanode and electrolyte. Full article

The selection of vascular grafts for coronary artery bypass surgery is crucial for a positive outcome. This study aimed to establish a novel line of vascular endothelial cells with a potent anticoagulant effect. A lentiviral vector was used to stably transfect human umbilical vein endothelial cells (HUVECs) with PGI2S alone (HUVEC-PGI2S) or both PGI2S and tPA (HUVEC-PGI2S-tPA). Both HUVEC-PGI2S and HUVEC-PGI2S-tPA cells over-expressing PGI2S and tPA were compared to mock-transfected cells. The enzyme-linked immuno sorbent assay (ELISAs) demonstrated that the anticoagulation components, ATIII and PLG, were up-regulated and coagulation factor FVIII was down-regulated in both cell lines. QRT-PCR and western blotting demonstrated the vasodilation and platelet disaggregation proteins PKA, PKC, and PTGIR were up-regulated in both cell lines, but MAPK expression was not altered in either cell line. However, cell viability and colony formation assays and cell cycle analysis demonstrated that both cell lines had a lower rate of cell growth and induced G1 phase arrest. HUVEC-PGI2S and HUVEC-PGI2S-tPA cells have a potent anticoagulant effect and their use in vascular heterografts may decrease the risk of thrombosis. Full article