Chain Reduction of CHCl3 Photocatalyzed by SPEEK/PVA Films Swollen in Air-Saturated HCO2Na Solutions.

Thin cross-linked films containing sulfonated poly(ether etherketone), SPEEK, and poly(vinyl alcohol), PVA, served as efficient photocatalysts for the reduction of CHCl3 when swollen in air-saturated solutions of formate buffers were photolyzed with 350 nm photons. The phototransformation generated CH2Cl2, CO2 and Cl- as products. The utilization of the continuous extraction method coupled with in situ potentiometry enabled kinetic determinations of the reaction progress. Quantum yields of halide ion formation, ϕ(Cl-), larger than 1 were obtained in the presence of air. These findings, together with the occurrence of a post-irradiation Cl- formation, indicated that the photoreduction took place via a chain process. Reductions photoinitiated by swollen films exhibited ϕ(Cl-) values between 3 and 20 times higher than the reactions induced in solutions containing the two polymers. Also, the dependencies of ϕ(Cl-) on CHCl3 or HCO2- concentration diverged significantly from the trends observed using solutions. Most findings are consistent with the occurrence of a reaction mechanism involving SPEEK radicals, •CO2- and •CHCl2 as chain carriers.

Natural radioactivity and its radiological implications from soils and rocks in Jaintiapur area, North-east Bangladesh.

Natural radioactivity concentrations in recent alluvial soils from swampy areas and Tertiary rocks from Jaintiapur were measured using gamma-ray spectrometer equipped with HPGe detector. The average radioactivity concentration of 226Ra, 232Th and 40K were 47 ± 6, 64 ± 5 and 762 ± 40 Bqkg-1 in soils, whereas, 25 ± 2, 37 ± 4 and 884 ± 41 Bqkg-1 in rock samples, respectively. Average radioactivity concentrations of studied soil and rock samples exceeded the world average except 226Ra for rocks. Radio-elemental ratios suggest that an oxic depositional environment with low uranium and high thorium content. Regarding radiological hazard indices, radium equivalent activities (Raeq), external hazard index (H ex) and internal hazard index (H in) was found to be below the world permissible limits. Whereas, absorbed dose rate (D), and annual effective dose equivalent (AEDE) averages exceeded the world admissible values. Statistical studies show that radioactivity for 226Ra and 232Th linked to a source enriched in radioactive minerals and 40K related to a different sources high in K enriched minerals.

Light absorption properties of brown carbon from biomass burning emissions.

A laboratory-scale experiment was conducted to determine the light absorption properties of brown carbon (BrC) produced from the incomplete combustion of 14 different biomasses. Particulate matters (PM) emitted from biomass burning were collected on the quartz fiber filters with a low volume sampler. BrC from filter samples was extracted with two different solvents (methanol and water), and absorption characteristics of BrC were determined using a UV-Vis spectrophotometer. The absorption coefficient (babs-BrC), mass absorption efficiency (MAEBrC), absorption angstrom exponent (AAEBrC), and absorbing portion of refractive index (kabs-BrC) were calculated for each biomass from the absorbance of the extracted solution. Methanol-soluble BrC (MeS-BrC) showed higher absorbance than water-soluble BrC (WS-BrC) in all biomasses. MeS-BrC has higher babs-BrC than WS-BrC, suggesting that the rate of light absorption on BrC extracted in methanol was higher. The absorption coefficients (babs-BrC) were varied among biomasses-rain tree had the highest value of babs-BrC, whereas jute stick had the lowest. The mass absorption efficiency of BrC (MAEBrC) was evaluated in both water and methanol extracts, and it was found that the MAEBrC for MeS-BrC in the biomasses was greater than that of WS-BrC. The highest MAEBrC value (13.02 m2g-1) was identified in the jackfruit tree, whereas the lowest MAEBrC value (0.1 m2g-1) was observed in the jute stick. The absorption angstrom exponent (AAE) of both WS-BrC and MeS-BrC was determined which represents the light absorption capacity of the aerosol particles. The highest AAE value was found in cow dung, and the lowest was found in rain tree. The increasing pH of the WS-BrC solution increased its optical absorption. However, this study revealed that the light absorption properties of brown carbon emitted from commonly used biomasses were varied significantly.

Genetic Polymorphism of miR-218-2 (rs11134527) in Cervical Cancer: A Case-Control Study on the Bangladeshi Women.

BACKGROUND: The prevalence of Cervical Cancer (CC) is disproportionately higher in developing countries. It is the second most frequent cancer type among Bangladeshi women and the major cause of morbidity and mortality. However, no previous data reported the association of miR-218-2 gene polymorphisms in Bangladeshi cervical cancer patients. AIM: This case-control study was designed to find the link between the rs11134527 polymorphism in miR-218-2 and CC. METHODS: A total of 488 subjects were recruited, comprising 256 cervical cancer patients and 232 healthy females. Genotyping was conducted with the tetra-primer ARMS-PCR technique to detect the association. RESULTS: The results of genotype data showed that rs11134527 was in the Hardy-Weinberg equilibrium in both CC cases and controls (P >0.05). Overall, the polymorphism was found to be significantly associated with an increased risk of cervical cancer with AG genotype (AG vs. GG: OR = 2.26, 95% Cl = 1.40-3.66, P = 0.0008), AA genotype (AA vs. GG: OR = 3.64, 95% Cl = 2.17-6.10, P <0.0001), dominant model (AG+AA vs. GG: OR = 2.75, 95% Cl = 1.75-4.31, P <0.0001), recessive model (AA vs. GG+AG: OR = 2.08, 95% Cl = 1.41-3.08, P = 0.0002), and A allele (A vs. G: OR = 1.94, 95% Cl = 1.51-2.51, P <0.0001). All of these correlations remained statistically significant after performing Bonferroni correction (P <0.008). CONCLUSION: Our study suggests that the rs11134527 polymorphism in the miR-218-2 gene contributes to the susceptibility of CC in Bangladeshi women.

Sirtuin 7 is involved in the consolidation of fear memory in mice.

Sirtuin 7 (SIRT7) is an NAD+-dependent deacetylase/deacylase, and is involved in a variety of biological processes relevant to the transcription of rRNA, the DNA damage response, tumorigenesis, and metabolism. SIRT7 mRNA is expressed ubiquitously, including in the brain, but there is no detailed information about the anatomical distribution and functional role of SIRT7 in the brain. Here, we demonstrated that SIRT7 is widely expressed in the mouse brain, including in the cortex, striatum, thalamus, hippocampus, and amygdala. Behavioral examinations revealed that Sirt7 knockout (KO) and control mice showed similar levels of freezing behavior immediately after a fear response, but a significant decrease of freezing behavior at 24 h after fear conditioning was observed in Sirt7 KO mice. Histological analysis revealed that there is no apparent structural abnormality of the amygdala and hippocampus, which are regions involved in fear memory consolidation, in Sirt7 KO mice. Our results indicate that SIRT7 is involved in the consolidation of fear memory.