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901.
Alternative normalization method of atmospheric polycyclic aromatic hydrocarbons pollution level recorded by tree bark 总被引:1,自引:0,他引:1
Zhao Y Wang Q Yang L Li Z Satake K Tsunoda K 《Environmental science & technology》2006,40(19):5853-5859
An alternative normalization method was developed for evaluating atmospheric polycyclic aromatic hydrocarbons (PAHs) pollution level when using tree bark as a passive sampling medium. Perylene (PER), which mainly stems from natural biogenic processes, was proposed as a "natural internal compound" (NIC) of atmospheric PAHs accumulation processes from air into the bark, and a concentration ratio of target PAH to PER (RPAH/PER) was used to minimize the uncertainty in the evaluation of atmospheric PAHs pollution level. Systematic investigation of the effects of intrinsic bark characteristics and extrinsic seasonal meteorological conditions on the partition processes of atmospheric PAHs indicated that RPAH/PER is as an alternative index as compared to bark mass concentration (BMCPAH, ng/g dry bark), lipid mass concentration (LMCPAH, ng/g lipid of bark), and area mass concentration (AMCPAH, ng/m2 surface area of bark) for the evaluation of atmospheric PAHs pollution and that it allows more flexible sampling of tree barks. Clearly, the methodology should be expected to be useful for the objective evaluation of atmospheric pollution levels of other persistent organic pollutants when using tree bark and other passive sampling media if corresponding NICs are found in the future. 相似文献
902.
Kanno S Kawamura Y Mutsuga M Tanamoto K 《Shokuhin eiseigaku zasshi. Journal of the Food Hygienic Society of Japan》2006,47(4):196-199
Epoxidized soybean oil (ESBO) was surveyed in the 103 samples of cap sealing for bottled foods on the Japanese market. Most of the sealings were made of polyvinyl chloride, while a few were made of polyethylene or acrylic resin. All the sealings contained ESBO in the range of 0.006-42.4%. Sealings for baby food, jam, etc. contained higher levels of ESBO, though those for beverages contained lower levels. Sealings in lug caps and press-on twist caps contained higher levels of ESBO, though that in pilfer-proof caps contained lower levels. Some sealings in screw caps and lug caps also contained other plasticizers, for example, di-2-ethylhexyl phthalate and diisononyl phthalate, and their ESBO contents were 1/10 of those in sealings containing only ESBO. In this survey, ESBO was the most common plasticizer in cap sealing resin for bottled foods on the Japanese market. 相似文献
903.
Kitamura Y Iwasaki T Saito M Mifune M Saito Y Sato K Yomota C Tanamoto K 《Shokuhin eiseigaku zasshi. Journal of the Food Hygienic Society of Japan》2006,47(5):232-236
The infrared absorption (IR) spectrum is often used as a standard reference in identification tests of food additives in Japan. In the case of betaine, many different IR spectra have been reported and, therefore, it is necessary to establish an IR spectrum that is reproducible and reliable enough to be used as a standard for identification. In the present study, suitable conditions to obtain a standard IR spectrum were examined from various viewpoints, including pretreatment, selection of method, and measuring technique. The KBr disk method, which has generally been used to identify betaine, was found to be humidity-dependent, and there was also an interaction between betaine and KBr. A reproducible IR spectrum suitable as a standard could be obtained by drying betaine at 105 degrees C for 3 hours over phosphorus pentoxide, and then measuring the IR spectrum by the liquid paraffin (Nujol) paste method. 相似文献
904.
Kanno S Kawamura Y Mutsuga M Tanamoto K 《Shokuhin eiseigaku zasshi. Journal of the Food Hygienic Society of Japan》2006,47(3):89-94
A determination method was developed for epoxidized soybean oil (ESBO) and epoxidized linseed oil (ELO), which are used as plasticizers and/or stabilizers, in wrapping film and cap sealings. The ESBO method reported by Castle et al. was improved. Samples were extracted with acetone-hexane (3: 7), transmethylated under alkaline conditions, then derivatized to the 1,3-dioxolanes and analyzed by GC/MS. The recoveries of spiked ESBO and ELO were between 92.6% and 104.4%. The determination limits were 0.01 mg/g for ESBO and 0.02 mg/g for ELO in the wrapping film, and 0.04 mg/g and 0.08 mg/g in the cap sealing. ESBO and ELO were surveyed in 10 samples each of wrapping film and cap sealings currently available on the Japanese market. ESBO was found at 34.7-82.8 mg/g in polyvinyl chloride (PVC) wrapping films and at 5.47-399 mg/g in cap sealings. ELO was detected at 8.6-11.4 mg/g in polyvinylidene chloride (PVDC) wrapping films, and at 46.4 mg/g in a PVC wrapping film. 相似文献
905.
Fujimoto Y Uchida K Oyaizu M Hamano Y 《Shokuhin eiseigaku zasshi. Journal of the Food Hygienic Society of Japan》2007,48(4):118-123
The differences among the small spines of 6 species of puffers have been clarified by means of microscopic observation. Small spines of puffers arise from the basement, which is composed of spines protruding from the surface skin, with roots extending horizontally in all directions in the layer under the surface skin. Using the characteristic shapes of the basement, we have classified the puffer group of "Sansaifugu" (Takifugu flavidus) and "Mefugu" (T. obscurus) as Type I and the group of "Shirosabafugu" (Lagocephalus wheeleri), "Kurosabafugu" (L. gloveri), "Dokusabafugu" (L. lunaris) and "Motosabafugu" (L. spadiceus) as Type II. The number of fore and back roots, including the branches at the ends, further varies in each group. The length and width of each root were measured. As a result, similar species within the group comprising "Sansaifugu" (T. flavidus) and "Mefugu" (T. obscurus) and 4 species of the "Sabafugu" (Lagocephalus) group including "Dokusabafugu" (L. lunaris) have been clearly distinguished. We conclude that examination of the shape of the basement of small spines can be an effective identification index. 相似文献
906.
Charalampos Konstantinou Giovanna Biscontin Ning-Jun Jiang Kenichi Soga 《岩石力学与岩土工程学报(英文版)》2021,13(3):579-592
It is difficult to collect and characterise well-preserved samples of weakly-cemented granular rocks as conventional sampling techniques o ften result in destruction of the cementation.An alternative approach is to prepare synthetic geomaterials to match required specifications.This paper introduces microbially induced carbonate precipitation(MICP) as a method to reliably deliverartificially cemented specimens with customised properties,closely resembling those of so ft carbonate sandstones.The specimens are generated from materials with two highly different particle size distributions(PSDs) to access a range of achievable combinations of strengths and porosities.The MICP parameters are kept constant across all samples to obtain similar calcium carbonate characteristics(size of individual crystals,type,etc.),while injected volume is varied to achieve different cementation levels.Although uniform cementation of very coarse sands has been considered very difficult to achieve,the results show that both the fine and coarse sand specimens present high degrees of uniformity and a good degree of repeatability.The unconfined compressive strengths(UCSs)(less than 3000 kPa) and porosities(0.25-0.4) of the artificial specimens fall in the same range of values reported for natural rocks.The strength gain was greater in the fine sand than that in the coarse sand,as the void size in the latter was significantly larger compared to the calcium carbonate crystals' size,resulting in precipitation on less effective locations,away from contacts between particles.The strengths and porosities obtained for the two sands in this work fall within ranges reported in the literature for natural soft rocks,demonstrating the MICP technique is able to achieve realistic properties and may be used to produce a full range of properties by varying the grain sizes,and possibly the width of PSD. 相似文献
907.
908.
Mayu Shono Gen Honda Miho Yanagisawa Kenichi Yoshikawa Akihisa Shioi 《Small (Weinheim an der Bergstrasse, Germany)》2023,19(38):2302193
In this study, a one-step method is discussed for producing uniform cell-sized microgels using glass capillaries filled with a binary polymer blend of polyethylene glycol (PEG) and gelatin. Upon decreasing temperature, phase separation of the PEG/gelatin blends and gelation of gelatin occur, and then the polymer blend forms linearly aligned, uniformly sized gelatin microgels in the glass capillary. When DNA is added to the polymer solution, gelatin microgels entrapping DNA are spontaneously formed, and the DNA prevents the coalescence of the microdroplets even at temperatures above the melting point. This novel method to form uniform cell-sized microgels may be applicable to other biopolymers. This method is expected to contribute to diverse materials science via biopolymer microgels and biophysics and synthetic biology through cellular models containing biopolymer gels. 相似文献
909.
Dr. Yanan Du Dr. Anyarat Thanapipatsiri Prof. Kenichi Yokoyama 《Chembiochem : a European journal of chemical biology》2023,24(17):e202300342
Nucleoside natural products show diverse biological activities and serve as leads for various application purposes, including human and veterinary medicine and agriculture. Studies in the past decade revealed that these nucleosides are biosynthesized through divergent mechanisms, in which early steps of the pathways can be classified into two types (C5' oxidation and C5' radical extension), while the structural diversity is created by downstream tailoring enzymes. Based on this biosynthetic logic, we investigated the genome mining discovery potentials of these nucleosides using the two enzymes representing the two types of C5' modifications: LipL-type α-ketoglutarate (α-KG) and Fe-dependent oxygenases and NikJ-type radical S-adenosyl-L-methionine (SAM) enzymes. The results suggest that this approach allows discovery of putative nucleoside biosynthetic gene clusters (BGCs) and the prediction of the core nucleoside structures. The results also revealed the distribution of these pathways in nature and implied the possibility of future genome mining discovery of novel nucleoside natural products. 相似文献
910.
Shinya Sekizaki Teruyuki Kato Ichiro Nishizaki Tomohiro Hayashida Kazuhisa Hikoyama Tomoaki Nonoyama 《Electrical Engineering in Japan》2023,216(3):e23442
The service restoration to sound sections within a short period as much as possible, performed after the permanent fault occurs in a distribution system, is significant for maintaining power supply reliability. This paper proposes an efficient method to find service restoration procedures based on fault searching and the optimal work scheduling of crews, considering the power supply priorities of loads and the probability of occurrence of faults. The proposed method is composed of two-stage problems to reduce the outage sections efficiently: (i) the problem to find a series of searching procedures for unknown fault locations in the first stage and (ii) the optimization problem of work schedules of crews in the second stage. In the first stage, the order of operation of switches opened for searching for the fault direction is determined, constituting the searching tree. After that, the proposed optimization method can efficiently solve the work scheduling problem by formulating it as a mixed-integer linear programming problem in the second stage. The computational experiments using a large-scale distribution system model with many remote and manual switches show that the proposed method can provide efficient service restoration procedures within a reasonable computational time. 相似文献