Quantitative analysis of α-mangostin in hydrophilic ointment using near-infrared spectroscopy

The objective of this research was to quantify the α-mangostin content in mangosteen pericarp (MP) ointment as a colloidal dispersion using near-infrared (NIR) spectroscopy. Various concentrations of MP (IP and EP) ointments containing both internal and external pericarps were prepared and the NIR spectra of these ointments were measured. The NIR spectrum of each ointment was correlated with α-mangostin concentration by partial least square (PLS) regression. Validation of the models was performed and their predictive ability was also investigated. The equation and R² value for the prediction of α-mangostin concentration in IP ointment were y?=?0.9843x?+?0.4441 and 0.9730 and those in EP ointment were y?=?0.9569x?+?0.1142 and 0.9136, respectively. The biases of the IP and EP ointment models were 0.23 and 0.00, respectively. The results showed that NIR could be a useful tool for the quality control of herbal medicine in hydrophilic ointment without any sample preparation. It could predict α-mangostin content in hydrophilic ointment at very low concentration with sufficient accuracy.     

离子筛MnO_2·0.4H_2O的固相法制备及特性研究

以单水氢氧化锂和四氧化三锰为原料,用固相法制备出锂离子筛锰酸锂,改变n(锂)/n(锰)之后,用同样的方法制备出另一物质Li1.33Mn1.67O4,经硝酸洗涤脱锂后制备了锂离子筛MnO2·0.4H2O。测定了酸洗时前驱体的锂洗脱率、锰溶损率,研究了锂离子筛MnO2·0.4H2O的饱和吸附量、稳定性、pH滴定曲线。结果表明,前驱体Li1.33Mn1.67O4经硝酸二次酸洗后,锂洗脱率和锰溶损率分别为62.7%和6.0%。在含0.1 mol/L氢氧化钠和10 mmol/L氯化锂的溶液中,经固相法制备的锂离子筛MnO2·0.4H2O对锂离子的饱和吸附量达到24.6 mg/g,并且具有较好的稳定性,pH滴定曲线表明锂离子筛对锂离子具有很好的选择性。     

Network copolyesters from benzenepolycarboxylic acids and 1,6-hexanediol

Network copolyesters were prepared from trimesic (Y), pyromellitic (X) or mellitic (Y_H) acids and 1,6-hexanediol (6G). Prepolymers prepared by meltpolycondensation were cast from dimethylformamide solution and postpolymerized at 260°C for 6h to form a network. The resultant films were transparent, flexible and insoluble in any organic solvents. Degree of reaction estimated from the infrared absorbance of ester and methylene groups was almost the same for all films, 94–96%. X-ray diffraction intensity curves and densities showed that the ordering of networks was decreased by the copolymerization, which was remarkable for 6G–X/Y_H copolymer films and was consistent with the higher decreases of heat-distortion temperature for these copolymer films. The copolymerization also caused decrease of thermal stability, tensile properties and alkali resistance and increase of dye absorption.     

Optimum design of integrated tandem-type a-Si solar cell submodule

A new optimum design, in which the actual daily spectral data under outdoor conditions over a year were considered, was developed for the integrated tandem-type a-Si solar cell submodule with a structure of glass/TCO/a-Si: H(pinpin)/metal. It was found by this design that the optimum cell number connected in series, at which maximum total annual output power was obtained, was small compared with that obtained by the conventional optimum design under standard conditions (AM1.5, 100 mW cm⁻²). It was also found that when light-induced degradation was considered, the thickness of the i-layer for the second pin cell was thinner than that by the conventional optimum design.     

Fluorescent in situ hybridization analysis of open lactic acid fermentation of kitchen refuse using rRNA-targeted oligonucleotide probes

Reproducible amounts of lactic acid accumulate in minced kitchen refuse under open conditions with intermittent pH neutralization [Sakai et al., Food Sci. Technol. Res., 6, 140 (2000)]. Here, we showed that such pH-controlled open fermentation of kitchen refuse reproducibly resulted a selective proliferation of a major lactic acid bacterial (LAB) species. In one experiment, the predominant microorganisms isolated during the early phase (6 h) were Gammaproteobacteria. In contrast, those that predominated during the late phase (48 h) were always Lactobacillus plantarum in three independent experiments. To further quantify the microbial community within open lactic acid fermentation, we performed fluorescent in situ hybridization (FISH) analysis targeting 16S (23S) rRNA. We designed two new group-specific DNA probes: LAC722(L) was active for most LAB including the genera Lactobacillus, Pediococcus, Leuconostoc and Weisella, whereas Lplan477 was specific for L. plantarum and its related species. We then optimized sample preparation using lysozyme and hybridization conditions including temperature, as well as the formamide concentration and the salt concentration in the washing buffer. We succeeded in quantification of microorganisms in semi-solid, complex biological materials such as minced kitchen refuse by taking color microphotographs in modified RGB balance on pre-coated slides. FISH analysis of the fermentation of kitchen refuse indicated that control of the pH swing leads to domination by the LAB population in minced kitchen refuse under open conditions. We also confirmed that L. plantarum, which generates lactic acid in high quantities but with low optical activity, became the dominant microorganism in kitchen refuse during the late phase of open fermentation.     

A novel hemiacetal dehydrogenase activity involved in ethyl acetate synthesis in Candida utilis

Acetate ester synthesis was studied in vitro with the ethyl acetate-producing yeast Candida utilis. The level of enzyme activity observed for the NAD+-dependent hemiacetal dehydrogenase acting on hemiacetal, which was produced non-enzymatically from an alcohol and an aldehyde, was much greater than that for the other enzyme involved in ester synthesis, alcohol acetyltransferase. The level of ethyl acetate synthesis in vivo approximately paralleled the hemiacetal dehydrogenase (HADH) activity. The results suggest that the main pathway for ethyl acetate synthesis in C. utilis involves a novel hemiacetal dehydrogenase activity.     

Open dumping site in Asian developing countries: a potential source of polychlorinated dibenz-p-dioxins and polychlorinated dibenzofurans

Open landfill dumping areas for municipal wastes in Asian developing countries have recently received particular attention with regard to environmental pollution problems. Because of the uncontrolled burning of solid wastes, elevated contamination by various toxic chemicals including dioxins and related compounds in these dumping sites has been anticipated. In this study, concentrations of polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs), and coplanar polychlorinated biphenyls (PCBs) were determined in soils from dumping sites in the Philippines, Cambodia, India, and Vietnam. Residue concentrations of PCDD/Fs and coplanar PCBs in dumping site soils were apparently greater than those in soils collected in agricultural or urban areas far from dumping sites, suggesting that dumping sites are potential sources of PCDD/Fs and related compounds. Observed PCDD/F concentrations in soils from dumping sites in the Philippines and Cambodia were comparable or higher than those reported for dioxin-contaminated locations in the world (e.g., near the municipal waste incinerators and open landfill dumping sites). Homologue profiles of PCDD/Fs in dumping site soils from the Philippines and, to a lesser extent, from Cambodia and India reflected patterns of samples representing typical emissions, while profiles of agricultural or urban soils were similar to those of typical environmental sinks. This result suggests recent formation of PCDD/Fs in dumping site areas and that open dumping sites are a potential source of dioxins in Asian developing countries. Uncontrolled combustions of solid wastes by waste pickers, generation of methane gas, and low-temperature burning can be major factors for the formation of dioxins in dumping sites. Elevated fluxes of PCDD/Fs to soils in dumping sites were encountered in the Philippines, Cambodia, India, and Vietnam-Hanoi, and these levels were higher than those reported for other countries. Considerable loading rates of PCDD/Fs in the dumping sites of these countries were observed, ranging from 20 to 3900 mg/yr (0.12-35 mg TEQ/yr). PCDD/F concentrations in some soil samples from the Philippines, Cambodia, India, and Vietnam-Hanoi exceeded environmental guideline values, suggesting potential health effects on humans and wildlife living near these dumping sites. The estimated intakes of dioxins via soil ingestion and dermal exposure for children were higher than those for adults, suggesting greater risk of dioxin exposure for children in dumping sites. To our knowledge, this is the first comprehensive study on PCDD/Fs contamination in open dumping sites of Asian developing countries. On the basis of the result of this study, we have addressed a new environmental issue that open dumping sites are potential sources of PCDD/Fs and related compounds, and dioxin contamination in dumping sites may become a key environmental problem in developing countries.     

Subcellular localization of fructosyl amino acid oxidases in peroxisomes of Aspergillus terreus and Penicillium janthinellum

Fructosyl amino acid oxidase (FAOD) is the enzyme catalyzing the oxidative deglycation of Amadori compounds, such as fructosyl amino acids, yielding the corresponding amino acids, glucosone, and H(2)O(2). In a previous report, we determined the primary structures of cDNAs coding for FAODs from two fungal strains Aspergillus terreus AP1 and Penicillium janthinellum and we found that both fungal FAODs included the putative peroxisome targeting signal 1 (PTS1) at the carboxyl terminal (Yoshida, N. et al., Eur. J. Biochem., 242, 499-505, 1996). In this study, we determined the intracellular localization of FAODs in these two fungi. Subcellular fractionation experiments and immuno-electronmicroscopic observations, together with the previous findings indicated that the FAODs were localized in peroxisomes of A. terreus AP1 and P. janthinellum. These FAODs were also found to belong to a new member of "peroxisomal sarcosine oxidase family protein" in eucaryotic cells.