3,017 research outputs found
Recombinant lignin peroxidase-catalyzed decolorization of melanin using in-situ generated H2O2 for application in whitening cosmetics
Lignin peroxidase has high potential as ingredient in skin whitening cosmetics due to its high redox potential to oxidize recalcitrant melanin. Currently crude mixtures of lignin peroxidase from fungal fermentation are usually applied to cosmetics due to the intrinsic difficulties of expression and purification. However, the present study focused on heterologous expression and purification of lignin peroxidase isozyme H8 (LiPH8) from Phanerochaete chrysosporium and was further used for melanin decolorization. Results revealed that the optimum pH for melanin decolorization using LiPH8 was obtained at pH???4.0. The intermittent feeding of hydrogen peroxide (H2O2) was effectively elevating melanin decolorization efficiency up to 73%, since excessive H2O2 inactivated LiPH8. For cosmetic application, intermittent feeding of H2O2 is not feasible, thus glucose oxidase (GOx) from Aspergillus niger was employed for in-situ generation of H2O2. By optimizing the GOx and glucose concentrations, a melanin decolorization efficiency up to 63.3????????2.4% was obtained within 1???h and continued to 84.0????????1.8% in 8???h. Conclusively, lignin peroxidase-catalyzed decolorization of melanin with in-situ generated H2O2 revealed a promising approach for whitening cosmetics applications
Titanium oxide Films Prepared by Sputtering, Sol Gel and Dip Coating Methods for Photovoltaic Application
AbstractDye-sensitized solar cells (DSCs) without using transparent conducting oxides (TCO) electrode can be produced at much lower cost with a flexible structure. A new type of DSCs using flexible stainless steel mesh sheets based electrode is reported in this research. The working electrode of DSCs is processed with conductive and flexible stainless mesh coated with metal oxides (TiO2) layer either by sputtering, sol gel or dip coating methods. Structures of the TCO-less DSCs sample is a stainless mesh for working electrode/dye sensitized TiO2 layer/liquid type electrolyte with polymer film/Pt doped Ti plate for counter electrode. The metal oxide coated stainless mesh sample showed higher photo-current conversion efficiency in general. The best cell performance in this experiment showed the efficiency of 3.11% (Voc = 0.58V, Jsc = 11.98mA/cm2, ff = 0.45)
Low-Power Complementary Inverter Based on Graphene/Carbon-Nanotube and Graphene/MoS<sub>2</sub> Barristors
The recent report of a p-type graphene(Gr)/carbon-nanotube(CNT) barristor facilitates the application of graphene barristors in the fabrication of complementary logic devices. Here, a complementary inverter is presented that combines a p-type Gr/CNT barristor with a n-type Gr/MoS2 barristor, and its characteristics are reported. A sub-nW (~0.2 nW) low-power inverter is demonstrated with a moderate gain of 2.5 at an equivalent oxide thickness (EOT) of ~15 nm. Compared to inverters based on field-effect transistors, the sub-nW power consumption was achieved at a much larger EOT, which was attributed to the excellent switching characteristics of Gr barristors
Role of G{alpha}12 and G{alpha}13 as Novel Switches for the Activity of Nrf2, a Key Antioxidative Transcription Factor
G{alpha}12 and G{alpha}13 function as molecular regulators responding to extracellular stimuli. NF-E2-related factor 2 (Nrf2) is involved in a protective adaptive response to oxidative stress. This study investigated the regulation of Nrf2 by G{alpha}12 and G{alpha}13. A deficiency of G{alpha}12, but not of G{alpha}13, enhanced Nrf2 activity and target gene transactivation in embryo fibroblasts. In mice, G{alpha}12 knockout activated Nrf2 and thereby facilitated heme catabolism to bilirubin and its glucuronosyl conjugations. An oligonucleotide microarray demonstrated the transactivation of Nrf2 target genes by G{alpha}12 gene knockout. G{alpha}12 deficiency reduced Jun N-terminal protein kinase (JNK)-dependent Nrf2 ubiquitination required for proteasomal degradation, and so did G{alpha}13 deficiency. The absence of G{alpha}12, but not of G{alpha}13, increased protein kinase C {delta} (PKC {delta}) activation and the PKC {delta}-mediated serine phosphorylation of Nrf2. G{alpha}13 gene knockout or knockdown abrogated the Nrf2 phosphorylation induced by G{alpha}12 deficiency, suggesting that relief from G{alpha}12 repression leads to the G{alpha}13-mediated activation of Nrf2. Constitutive activation of G{alpha}13 promoted Nrf2 activity and target gene induction via Rho-mediated PKC {delta} activation, corroborating positive regulation by G{alpha}13. In summary, G{alpha}12 and G{alpha}13 transmit a JNK-dependent signal for Nrf2 ubiquitination, whereas G{alpha}13 regulates Rho-PKC {delta}-mediated Nrf2 phosphorylation, which is negatively balanced by G{alpha}12
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Splenectomy is associated with an aggressive tumor growth pattern and altered host immunity in an orthotopic syngeneic murine pancreatic cancer model.
The purpose of this study was to investigate whether splenectomy influences the tumor growth and metastatic pattern in an orthotopic syngeneic murine pancreatic cancer model. Murine pancreatic cancer cells (PAN02) were subcutaneously injected into the flanks of nude mice. A small tumor fragment (3 mm2), harvested from a subcutaneous tumor. was orthotopically implanted in the tail of the pancreas of C57/BL6 mice without splenectomy (control group, n=15) or with simultaneous splenectomy (splenectomy group, n=15). Tumor growth and metastatic patterns were analyzed by laparotomy at 21 days after surgery. No tumor growth was found in 5 mice (33.3%) of the control group and 1 mouse (6.7%) of the splenectomy group (p=0.169). Tumor volume was significantly larger in splenectomy group (p=0.013). Peritoneal seeding was more frequently observed in the splenectomy group (11 (73.3%) vs. 4 (26.7%), p=0.011). There were no differences in the number of liver and kidney metastasis between the two groups. The ratios of tumor-infiltrating CD4+ to FoxP3+ and CD8+ to FoxP3+ were significantly higher in the control group compared to the splenectomy group (8.2 Β± 9.3 vs. 2.4 Β± 1.5, p=0.046; 2.5 Β± 1.4 vs. 1.5 Β± 0.4, p=0.031, respectively). Splenectomy enhanced tumor growth and peritoneal seeding in an orthotopic syngeneic murine pancreatic cancer mouse model. The ramification of these results are discussed for pancreatic cancer treatment
Crude Extracts of Caenorhabditis elegans Suppress Airway Inflammation in a Murine Model of Allergic Asthma
Epidemiological studies suggest an inverse relationship between helminth infections and allergic disease, and several helminth-derived products have been shown to suppress allergic responses in animals. This study was undertaken to evaluate the effect of a crude extract of Caenorhabditis elegans on allergic airway inflammation in a murine model of asthma. Allergic airway inflammation was induced in BALB/c mice by sensitization with ovalbumin. The effect of the C. elegans crude extract on the development of asthma and on established asthma was evaluated by analyzing airway hyperresponsiveness, serum antibody titers, lung histology and cell counts and cytokine levels in the bronchoalveolar lavage fluid. The role of IFN-Ξ³ in the suppression of asthma by the C. elegans crude extract was investigated in IFN-Ξ³ knockout and wild-type mice. When mice were sensitized with ovalbumin together with the crude extract of C. elegans, cellular infiltration into the lung was dramatically reduced in comparison with the ovalbumin-treated group. Treatment of mice with the C. elegans crude extract significantly decreased methacholine-induced airway hyperresponsiveness and the total cell counts and levels of IL-4, IL-5 and IL-13 in the bronchoalveolar lavage fluid but increased the levels of IFN-Ξ³ and IL-12. Sensitization with the C. elegans crude extract significantly diminished the IgE and IgG1 responses but provoked elevated IgG2a levels. However, the suppressive effect of the C. elegans crude extract was abolished in IFN-Ξ³ knockout mice, and the Th2 responses in these mice were as strong as those in wild-type mice sensitized with ovalbumin. The crude extract of C. elegans also suppressed the airway inflammation associated with established asthma. This study provides new insights into immune modulation by the C. elegans crude extract, which suppressed airway inflammation in mice not only during the development of asthma but also after its establishment by skewing allergen-induced Th2 responses to Th1 responses
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