Ekspansi Termal, Oxygen Content, dan Sifat Elektrokimia Oksida SmBa0.5Sr0.5Co2O5+δ (70%) + SDC (30%) Sebagai Katoda SOFC

The thermal properties of the double perovskite SmBa0.5Sr0.5Co2O5+δ (70%) + SDC (30%) have been investigated as potential cathodes for intermediate-temperature solid oxide fuel cells (IT-SOFC). This study also includes the oxygen content and electrochemical performance of long-term tests carried out to evaluate the electrochemical stability. Cathode powder is fabricated by a simple and relatively inexpensive solid-state reaction. Oxygen content decreased gradually from room temperature to 800oC by 18.3%. Doping 30% SDC into SBSC oxide can reduce the thermal expansion coefficients (TEC) value from 19.80 x 10-6 (K-1) to 18.17 x 10-6 (K-1) or a decrease of 8.23%. The activation energy (Ea) identified by the electrochemical impedance spectroscopy (EIS), low field (LF), and high field (HF) techniques were 125.3 kJ mol-1, 60.6 kJ mol-1, and 62.5 kJ mol-1, respectively. The SBSC73|SDC|SBSC73 symmetric cell test for 96 hours at 600oC showed an increase in the average polarization resistance value of 0.30% h-1. The cathode grains are evenly distributed with a size of 2-3 µm and tend to be porous. These results exhibit that SmBa0.5Sr0.5Co2O5+δ (70%) + SDC (30%) is a promising cathode material for IT-SOFCs

Structural and Electrochemical Analysis of SmBa0.8Sr0.2Co2O5+δ Cathode Oxide for IT-SOFCs

The double perovskite SmBa0.8Sr0.2Co2O5+δ (SBSC82) was prepared using a conventional technique and evaluated as solid oxide fuel cells (SOFCs) cathode material which operates at intermediate temperatures. The SBSC82 cathode powder was produced using the solid-state reaction technique and an alumina ball as a grinder. XRD was used to determine the cathode powder structure, and the microstructure was analyzed using SEM. The oxygen content (δ) for the SBSC82 cathode was recorded by a thermogravimetric analyzer. Powder patterns and lattice parameters were detected using General Structure Analysis System (GSAS) software. The symmetrical cell was examined using a Voltalab PGZ 301 potentiostat. The δ of SBSC82 cathode reached 5.68, 5.43, and 5.22 at 400 oC, 600 oC, and 800 oC. It was found that SBSC82 oxide shows a simple perovskite-type structure with tetragonal P4/mmm. The polarization resistance (Rp) of the symmetrical cell with SDC|SBCS82|SDC configuration reached of 0.420 Ωcm2, 0.091 Ωcm2, and 0.041 Ωcm2 at 650 oC, 750 oC, and 850 oC, respectively. Single cell specimen achieves a power density of 377 mW/cm2 under humidified air/hydrogen

Structural and Electrochemical Analysis of SmBa0.8Sr0.2Co2O5+δ Cathode Oxide for IT-SOFCs

The double perovskite SmBa0.8Sr0.2Co2O5+δ (SBSC82) was prepared using a conventional technique and evaluated as solid oxide fuel cells (SOFCs) cathode material which operates at intermediate temperatures. The SBSC82 cathode powder was produced using the solid-state reaction technique and an alumina ball as a grinder. XRD was used to determine the cathode powder structure, and the microstructure was analyzed using SEM. The oxygen content (δ) for the SBSC82 cathode was recorded by a thermogravimetric analyzer. Powder patterns and lattice parameters were detected using General Structure Analysis System (GSAS) software. The symmetrical cell was examined using a Voltalab PGZ 301 potentiostat. The δ of SBSC82 cathode reached 5.68, 5.43, and 5.22 at 400 oC, 600 oC, and 800 oC. It was found that SBSC82 oxide shows a simple perovskite-type structure with tetragonal P4/mmm. The polarization resistance (Rp) of the symmetrical cell with SDC|SBCS82|SDC configuration reached of 0.420 Ωcm2, 0.091 Ωcm2, and 0.041 Ωcm2 at 650 oC, 750 oC, and 850 oC, respectively. Single cell specimen achieves a power density of 377 mW/cm2 under humidified air/hydrogen

Zinc Sulfide Buffer Layer for CIGS Solar Cells Prepared by Chemical Bath Deposition

In this study, ZnS thin films were successfully synthesized by chemical bath deposition (CBD) with starting materials of NH2-NH2, SC(NH2)2, and ZnSO4‧7H2O. ZnS thin films were deposited with different time on glass substrates by CBD at 80oC and pH=9. Based on X-ray diffraction (XRD) patterns, it is found that the ZnS thin films exhibit cubic polycrystalline phase. It was found that the optimum deposition time is 90 min for preparing ZnS thin film that is suitable as buffer layer for CuIn1-xGaxSe2 solar cells. The thin film deposited for 90 min has high transmittance up to 80% in the spectra range from 350 nm to 800 nm, and the optical band gap is about 3.59 eV

Oxidation Pond for Municipal Wastewater Treatment

This literature review examines process, design, and cost issues related to using oxidation ponds for wastewater treatment. Many of the topics have applications at either full scale or in isolation for laboratory analysis. Oxidation ponds have many advantages. The oxidation pond treatment process is natural, because it uses microorganisms such as bacteria and algae. This makes the method of treatment cost-effective in terms of its construction, maintenance, and energy requirements. Oxidation ponds are also productive, because it generates effluent that can be used for other applications. Finally, oxidation ponds can be considered a sustainable method for treatment of wastewater

Tequila Regulates Insulin-Like Signaling and Extends Life Span in Drosophila melanogaster

The aging process is a universal phenomenon shared by all living organisms. The identification of longevity genes is important in that the study of these genes is likely to yield significant insights into human senescence. In this study, we have identified Tequila as a novel candidate gene involved in the regulation of longevity in Drosophila melanogaster. We have found that a hypomorphic mutation of Tequila (Teq(f01792)), as well as cell-specific downregulation of Tequila in insulin-producing neurons of the fly, significantly extends life span. Tequila deficiency-induced life-span extension is likely to be associated with reduced insulin-like signaling, because Tequila mutant flies display several common phenotypes of insulin dysregulation, including reduced circulating Drosophila insulin-like peptide 2 (Dilp2), reduced Akt phosphorylation, reduced body size, and altered glucose homeostasis. These observations suggest that Tequila may confer life-span extension by acting as a modulator of Drosophila insulin-like signaling

Sequence variants of the aging gene CISD2 and the risk for Alzheimer's disease

Background/PurposeThe CISD2 gene has been related to life span control and mitochondrial dysfunction in animals. In addition, inhibition of mitochondrial enzymes due to an accumulation of beta-amyloid peptide has been related to Alzheimer's disease (AD). This study aimed to explore the association between sequence variants of the CISD2 gene and risk for AD, which has not been explored previously.MethodsThis was a case–control study involving a total of 276 patients with AD who were recruited from three teaching hospitals in Taiwan from 2007 to 2010; 460 controls were recruited from elderly individuals attending for health check-ups and volunteers in the hospital during the same period of time. All participants were aged 60 years or older. Two haplotype-tagging single nucleotide polymorphisms (htSNPs), rs223330 and rs223331, were selected from the CISD2 gene to test the association between their polymorphisms and the risk for dementia, and how ApoE ɛ4 status, sex, hypertension, and type 2 diabetes mellitus might modify this association.Resultsrs223330 variant carriage was not associated with risk for AD [TT versus CC: adjusted odds ratio (AOR) = 0.98, 95% confidence interval (CI) = 0.59–1.62; TC versus CC: AOR = 0.72, 95% CI = 0.47–1.11]. Similar findings were observed for rs223331 (AA versus TT: AOR = 1.12; AT versus TT: AOR = 0.99). In addition, hypertension significantly modified the association between rs223331 and risk for AD (p = 0.005).Three common haplotypes (with a frequency of 99.8%) were observed for CISD2. Common CISD2 haplotypes were not associated with the risk for AD.ConclusionOur findings suggested that CISD2 htSNPs are not associated with AD risk

Serotonin receptor HTR6-mediated mTORC1 signaling regulates dietary restriction-induced memory enhancement

Dietary restriction (DR; sometimes called calorie restriction) has profound beneficial effects on physiological, psychological, and behavioral outcomes in animals and in humans. We have explored the molecular mechanism of DR-induced memory enhancement and demonstrate that dietary tryptophan-a precursor amino acid for serotonin biosynthesis in the brain-and serotonin receptor 5-hydroxytryptamine receptor 6 (HTR6) are crucial in mediating this process. We show that HTR6 inactivation diminishes DR-induced neurological alterations, including reduced dendritic complexity, increased spine density, and enhanced long-term potentiation (LTP) in hippocampal neurons. Moreover, we find that HTR6-mediated mechanistic target of rapamycin complex 1 (mTORC1) signaling is involved in DR-induced memory improvement. Our results suggest that the HTR6-mediated mTORC1 pathway may function as a nutrient sensor in hippocampal neurons to couple memory performance to dietary intake

Diversity of the association of serum levels and genetic variants of MHC class I polypeptide-related chain A with liver fibrosis in chronic hepatitis C

Background/Aims Genetic variants of MHC class I polypeptide-related chain A (MICA) at rs2596542 have been associated with hepatocellular carcinoma. The linkage between serum MICA (sMICA) and liver fibrosis in chronic hepatitis C is elusive. Results: Linear regression analysis revealed that sMICA were independently correlated to α-fetoprotein (β: 0.149; 95% confidence interval [CI]: 0.001, 0.003; P = 0.007)and MICA rs2596542 GG genotype (β: 0.209; 95% CI: 0.153, 0.483; P 50 pg/mL provided a positive predictive value of 72 % in predicting advanced liver fibrosis (F3-4) and of 90% in significant fibrosis (> F2) in MICA rs2596542 A allele carriers. Materials and Methods Serum level and single nucleotide polymorphism at rs2596542 of MICA were tested for the association with liver fibrosis in 319 biopsy proven chronic hepatitis C patients. Conclusions: Levels of sMICA were highly correlated to liver disease severity in chronic hepatitis C patients who carried the MICA rs738409 A allele. Patients possessing the genetic predisposition had a higher likelihood of progressed liver fibrosis if they expressed higher sMICA levels