Facile synthesis of titanium dioxide‐cadmium sulfide nanocomposite using pulsed laser ablation in liquid and its performance in photovoltaic and photocatalytic applications

Narrow band gap semiconductors like cadmium sulfide (CdS) are being applied as an agent to reduce the band gap of metal oxide semiconductors like titanium dioxide (TiO₂). In order to obtain a TiO₂/CdS nanocomposite with reduced electron‐hole recombination and improved stability, we coupled 10%, 20%, and 40% by weight of CdS with TiO₂ in this work using pulsed laser ablation in liquid technique. Here, 532 nm wavelength generated from neodymium‐doped yttrium aluminum garnet laser was directed into the TiO₂/CdS mixture prepared in a colloid form to produce the TiO₂/CdS nanocomposites. The effect of the CdS concentration on the performance of the obtained nanocomposite in a dye‐sensitized solar cell and photocatalytic degradation of methyl orange in water was studied in detail. However, the nanocomposite with 10% percentage weight of CdS in anatase TiO₂ showed the best performance as compared with pure TiO₂, and the photoconversion efficiency of the dye‐sensitized solar cell was improved from 0.6% to 4.3%, while the percentage of methyl orange degraded was enhanced from 58% to 82% after 36 min irradiation using ultraviolet–visible light. This improvement in photovoltaic and photodegradation properties is due to limited electron hole recombination rate, higher conduction of charge carriers, their longer lifetime during the photocatalytic process, improved ultraviolet–visible light activity, reduced photocorrosion, and improved pore size. Copyright © 2017 John Wiley & Sons, Ltd.     

Artificial Photosynthesis using LiNbO3 as Photocatalyst for Sustainable and Environmental Friendly Construction and Reduction of Global Warming: A Review

Artificial photosynthesis using LiNbO₃ as a photocatalyst has emerged as an important technology leading to the formation of eco-friendly end products. An interesting part of this technology is its ability to directly convert pollutants into the harmless substances in the contaminant source. This technology possesses enormous potential for the reduction of “global warming.” This article reviews recent developments and future potential applications of this emerging technology and provides information on the parameters that control its process. The effects of the photosynthetic reaction of LiNbO₃ on cementations materials and indoor air conditioning are also reviewed in this article.     

A transgressive brown rice mediates favourable glycaemic and insulin responses

BACKGROUND: We evaluated glycaemic response of a brown rice variant (BR) developed by cross‐breeding. Subjects (n = 9) consumed 50 g carbohydrate equivalents of BR, white rice (WR) and the polished brown rice (PR) in comparison to 50 g glucose reference (GLU) in a cross‐over design. Plasma glucose and insulin at 0, 15, 45, 60, 90, 120 and 180 min were measured and incremental area under the curve (IAUC) and indices for glucose (GI) and insulin (II) calculated. RESULTS: BR compared to PR or WR produced the lowest postprandial glycaemia (GI: 51 vs 79 vs 86) and insulinaemia (II: 39 vs 63 vs 68) irrespective of amylose content (19 vs 23 vs 26.5%). Only BR was significantly different from GLU for both plasma glucose (P = 0.012) and insulin (P = 0.013) as well as IAUC_glu (P = 0.045) and IAUC_ins (P = 0.031). Glycaemic and insulinaemic responses correlated positively (r = 0.550, P < 0.001). Linear trends for IAUC_glu and IAUC_ins indicated a greater secretion of insulin tied in with a greater glycaemic response for WR (r² = 0.848), moderate for PR (r² = 0.302) and weakest for BR (r² = 0.122). CONCLUSION: The brown rice variant had the lowest GI and II values but these advantages were lost with polishing. Copyright © 2011 Society of Chemical Industry     

Impact of environmental stress desiccation, acidity, alkalinity, heat or cold on antibiotic susceptibility of Cronobacter sakazakii

Cronobacter sakazakii is an emerging foodborne pathogen that has been implicated in severe forms of meningitis, septicemia or necrotizing colitis in pre-term neonates. Although illness outbreaks (primarily associated with powdered infant formula, PIF) caused by this pathogen are rare, the case-fatality rate may reach 50%. Successful treatment of C. sakazakii infection is reliant upon clinical use of antibiotics (AB) such as ampicillin. Recent reports showed increased resistance of C. sakazakii to broad-spectrum antibiotics. The objective of this study was to evaluate the effect of extreme pH (3.5 for 30 min or 11.25 for 5 min), cold (4 °C for 24 h), heat (55 °C for 5 min), and desiccation (cells were dried at 40 °C for 2 h and held at 21 °C for 4 d) stresses on susceptibility of five isolated strains of C. sakazakii to streptomycin, gentamicin, kanamycin, neomycin, tetracycline, doxycycline, tilmicosin, florfenicol, ampicillin, amoxicillin, vancomycin, ciprofloxacin and enrofloxacin. All unstressed strains of C. sakazakii were sensitive to streptomycin, gentamycin, kanamycin, ciprofloxacin, enrofloxacin, ampicillin and amoxicillin, but were moderately resistant or resistant to the rest. Exposing cells to alkaline or acidic stress did not change their sensitivity toward streptomycin, gentamycin, kanamycin or ciprofloxacin, but their resistance toward the other AB was increased. Cells stressed by desiccation showed increased sensitivity toward streptomycin, gentamicin, kanamycin, ciprofloxacin, enrofloxacin, ampicillin and doxycycline, but showed resistance toward the others. Cold-stressed cells were more sensitive to streptomycin, gentamicin, kanamycin, and ciprofloxacin compared with heat-stressed cells, but both heat and cold-stressed cells showed increased resistance toward all the other AB. Results obtained will help in understanding the effect of environmental stresses during processing on C. sakazakii susceptibility to AB.     

Structure‐Specific Recognition of Friedreich's Ataxia (GAA)n Repeats by Benzoquinoquinoxaline Derivatives

Expansion of GAA triplet repeats in intron 1 of the FXN gene reduces frataxin expression and causes Friedreich's ataxia. (GAA)_n repeats form non‐B‐DNA structures, including triple helix H‐DNA and higher‐order structures (sticky DNA). In the proposed mechanisms of frataxin gene silencing, central unanswered questions involve the characterization of non‐B‐DNA structure(s) that are strongly suggested to play a role in frataxin expression. Here we examined (GAA)_n binding by triplex‐stabilizing benzoquinoquinoxaline (BQQ) and the corresponding triplex‐DNA‐cleaving BQQ‐1,10‐phenanthroline (BQQ‐OP) compounds. We also examined the ability of these compounds to act as structural probes for H‐DNA formation within higher‐order structures at pathological frataxin sequences in plasmids. DNA‐complex‐formation analyses with a gel‐mobility‐shift assay and sequence‐specific probing of H‐DNA‐forming (GAA)_n sequences by single‐strand oligonucleotides and triplex‐directed cleavage demonstrated that a parallel pyrimidine (rather than purine) triplex is the more stable motif formed at (GAA)_n repeats under physiologically relevant conditions.     

Physics students' conceptions of energy and technological development in energy

There has been strong international interest in students' understanding concerning phenomenon taught in physics. Many studies have been conducted to find out students' conceptions in various concepts in physics. This study was designed to find out students' conceptions of the relationship of energy use and technological development in energy. It was conducted by administering a questionnaire to 133 first year physics students at a university. A questionnaire entitled “Questionnaire On Energy And Technological Development” was used to collect data for this study. The results were analyzed to identify students' conceptions on energy use and technological development in energy. Finally, implications on teaching of energy is discussed in this paper.     

Evaluation of Metal Concentrations in Red Tilapia (Oreochromis spp) from Three Sampling Sites in Jelebu, Malaysia Using Principal Component Analysis

Concentration of V, Mn, Fe, Co, Cu, Zn, As, Se, Cd, and Pb in muscle, liver, and gill tissues of red tilapia (Oreochromis spp) sampled from three different aquaculture sites which include earthen pond, ex-tin mining pool, and concrete tank in Jelebu, Negeri Sembilan, were determined using microwave-assisted digestion–inductively coupled plasma-mass spectrometry. Accumulation patterns relating organs and elements, as well as origins and elements, were evaluated using multivariate statistics. With the aid of principal component analysis, it is possible to visualize the distribution pattern of metals in different organs as well as clustering tendencies of tilapia samples according to the production sites. In general, levels of V, Co, Fe, Cu, Zn, Se, and Cd in liver were higher than those in muscles and gills, whereas Mn and Pb were higher in gills while As in muscles. Results from principal component analysis revealed that there are similar pattern of metal distribution among organs regardless of the production sites. It is also suggested that Cu, As, and Pb are the best describers in characterizing the studied organs, where liver tissues are associated with high Cu, gills with high Pb, and muscles with high As. On the other hand, V, Co, and Pb are observed to be key discriminants for sample origins.     

培养条件对乳酸菌发酵剂抗冷冻干燥性能影响的研究进展

乳酸菌发酵剂应具有高活力、耐贮藏性以及对不同环境的适应性,特别是在冷冻干燥过程中活性的保持。本文从乳酸菌发酵剂菌种的内在特性、培养时间、培养基成分、培养温度及pH值的变化等方面综述了不同培养条件对乳酸菌发酵剂抗冷冻干燥性能影响的研究进展。说明乳酸菌在冷冻干燥中的存活率依赖于它的内在基因,基因差别决定了不同的乳酸菌对冷冻干燥的抗性存在差异;同时与细胞膜成分以及菌株形态有一定的关联;通常生长在稳定期的乳酸菌其抗冷冻干燥能力较强;培养基成分对菌株的影响因菌株不同而异;较低的培养温度和pH值,有助于提高乳酸菌的抗冷冻干燥性能。本文为提高乳酸菌的冻干存活率提供一些参考。     

Utilization of foliar cuticle morphology for the identification of weedy grasses

For the robust identification of weeds of taxonomically complex families like Poaceae, scanning electron microscopy (SEM) and light microscopy (LM) are of significant implications. In this study, SEM and LM methods were used by investigating 12 Pakistani weedy grass species as an example for foliar epidermal micromorphological characters for its role in the identification of grasses species. Qualitative and quantitative foliar micromorphological variations in stomatal type, number, guard cells, subsidiary cells, silica bodies and trichomes were studied. Significant variation was observed in both qualitative and quantitative features and based on this diversity in epidermal characters, a key was drawn to delimitate the species. Variations in stomata, silica bodies (SiO₂·nH₂O), macrohairs, microhairs, hooks, papillae, prickles, and other epidermal structures were used in establishing the taxonomic key. The data were also statistically evaluated by determining its mean, standard deviation, variance, the coefficient of variance, and standard error. Foliar epidermal characters such as silica bodies shape and trichomes were taxonomically more useful than stomatal types, subsidiary, and guard cells. SEM and LM micromorphological characters were of substantial importance in the delimitation of closely related species.