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排序方式: 共有925条查询结果,搜索用时 625 毫秒
101.
Md. Shaheed Reza Nanami Mizusawa Ayaka Kumano Chiharu Oikawa Daisuke Ouchi Atsushi Kobiyama Yuichiro Yamada Yuri Ikeda Daisuke Ikeda Kazuho Ikeo Shigeru Sato Takehiko Ogata Toshiaki Kudo Mitsuru Jimbo Ko Yasumoto Kazutoshi Yoshitake Shugo Watabe 《Fisheries Science》2018,84(3):563-577
In an effort to determine genus- or species-level taxonomic profiles and diversity of bacterial consortia in the Tama River around urban Tokyo, next-generation sequencing technology targeting a 16S ribosomal RNA (rRNA) gene amplicon was employed. Metagenomic analysis performed by an Ion Personal Genome Machine after sequentially filtering samples through 5-, 0.8- and 0.2-μm filters yielded 1.48 Gb of 16S sequences (average 2.38 M reads/sample). The results indicated that half of the bacterial sequences belonged to Proteobacteria, followed by Bacteroidetes, Actinobacteria and Cyanobacteria. Flavobacterium (Bacteroidetes), possibly including a potential fish pathogen, was the most numerous genera in the Tama River metagenome, and accounted for?~?16% of assigned 16S reads, followed by Mycobacterium. Other dominant bacterial genera including Zoogloea, Sediminibacterium, Hyphomicrobium, Sphingopyxis, Thiothrix and Lysobacter, were thought to be associated with waste water and sludge. MiSeq metagenomic analysis revealed that environmental factors, particularly water temperature, influenced the bacterial composition throughout the year, with a strong negative correlation observed for Proteobacteria and a positive correlation for Bacteroidetes. In terms of bacterial genera, Flavobacterium was positively correlated with temperature, while Polaromonas, Pseudomonas and Bradyrhizobium were negatively correlated with this, suggesting dynamic change in the free-living bacterial population throughout the year and versatile adaptation strategies in relation to environmental factors. 相似文献
102.
Fatemeh RAJAEI Abbas E SARI Abdolrassoul SALMANMAHINY Timothy O RANDHIR Majid DELAVAR Reza D BEHROOZ Alireza M BAVANI 《干旱区科学》2018,10(3):457-469
Conversion of forest land to farmland in the Hyrcanian forest of northern Iran increases the nutrient input, especially the phosphorus(P) nutrient, thus impacting the water quality. Modeling the effect of forest loss on surface water quality provides valuable information for forest management. This study predicts the future impacts of forest loss between 2010 and 2040 on P loading in the Tajan River watershed at the sub-watershed level. To understand drivers of the land cover, we used Land Change Modeler(LCM) combining with the Soil Water Assessment Tool(SWAT) model to simulate the impacts of land use change on P loading. We characterized priority management areas for locating comprehensive and cost-effective management practices at the sub-watershed level. Results show that agricultural expansion has led to an intense deforestation. During the future period 2010–2040, forest area is expected to decrease by 34,739 hm~2. And the areas of pasture and agriculture are expected to increase by 7668 and 27,071 hm~2, respectively. In most sub-watersheds, P pollution will be intensified with the increase in deforestation by the year 2040. And the P concentration is expected to increase from 0.08 to 2.30 mg/L in all of sub-watersheds by the year 2040. It should be noted that the phosphorous concentration exceeds the American Public Health Association′s water quality standard of 0.2 mg/L for P in drinking water in both current and future scenarios in the Tajan River watershed. Only 30% of sub-watersheds will comply with the water quality standards by the year 2040. The finding of the present study highlights the importance of conserving forest area to maintain a stable water quality. 相似文献
103.
M. Khataar M. R. Mosaddeghi Reza Amiri Chayjan A. A. Mahboubi 《Paddy and Water Environment》2018,16(3):631-641
This study was conducted to investigate the impact of water salinity (ECw) and sodicity (SARw) on saturated (Ks) and relative (Kr) hydraulic conductivities in two clay (C) and sandy clay loam (SCL) soils. The results showed that the Ks decreased with increasing SARw, and in all of water quality treatments, the Ks of SCL soil was higher than that of the C soil. Sodicity effect (even at high SARw) on the Kr of clay soil was minimized by high salinity. Although Kr of both soils similarly responded to ECw and SARw, microstructure of clay soil was more sensitive to water quality. Effect of ECw on soil structure was greater than that of SARw. In order to assess the applicability of artificial neural networks (ANNs) in estimating Ks and Kr, two types of FFBP and CFBP ANNs and two training algorithms, namely Levenberg–Marquardt (LM) and Bayesian regulation, were employed with two strategies of uniform threshold and different threshold functions. Multiple linear regressions were also used for Ks and Kr prediction. Based on the ANN results of second strategy, best topology (4–5–4–1) was belonged to CFBP network with LM algorithm, LOGSIG–LOGSIG–TANSIG threshold functions, and values of MAE and R2 are equal to 0.1761 and 0.9945, respectively. Overall, the efficacy of ANNs is much greater than regression method for Ks prediction. 相似文献
104.
Yasaman Etemadian Zohreh Ramzanpour Amir Reza Shaviklo Moazameh Kordjazi 《Journal Of Aquatic Food Product Technology》2018,27(2):219-235
Sirophysalis trinodis and Polycladia myrica, two brown seaweeds present on the southeast coast of Iran, were evaluated for their nutritional and functional properties after drying. Fourier transform-infrared spectroscopy (FTIR) analysis of crude polysaccharides revealed the characteristic absorption bands of phenol, O–H, C–H, C–O–S, C–O, C=O, C–H groups, and β-glycosidic linkages from cellulose, with the sulfate contents estimated as 4.89 ± 0.11% and 6.96 ± 0.05% of SO4?2. Results of nutritional profiles revealed all of the essential amino acids, especially methionine, isoleucine, leucine, lysine, threonine, valine, phenyl alanine, and arginine. In addition, important fatty acids such as linolenic acid, palmitic acid, and oleic acid were found in high amounts. The other nutritional components present in high amounts were proline and minerals such as calcium, magnesium, iron, manganese, copper, and zinc. The antibacterial activity was weak, but the result of antioxidant activities (hydroxyl and superoxide radicals scavenging and ferrous-ion chelating ability) of crude polysaccharides was considerable. In general, the findings of this study recommend that S. trinodis and P. myrica dried seaweeds have a potent nutritional value and might be used as a valuable source of nutrient supplements for humans and animals. 相似文献
105.
Mikhail Novikov Kwai Lin Thong Nur Izzurianna Mohd Zazali Sharifah Bee Abd Hamid 《Fibers and Polymers》2018,19(3):548-560
The efficacy of antimicrobial treatment of cotton fabrics depends on various parameters of the coating process, such as the chemical nature and concentration of the antimicrobial agent, the composition of the crosslinking formulation, and the curing temperature. The inclusion complex of triclosan with β-cyclodextrin (βCD) was synthesized and characterized by FTIR, XRD, NMR, Raman, SEM, and TGA. The minimum inhibitory concentration and minimum bactericidal concentration of the complex against Klebsiella pneumoniae and Staphylococcus aureus were compared to those of its precursor. A multifactorial study included an evaluation of the effects of triclosan complexation with β-cyclodextrin, a comparison between the glyoxal and tetracarboxylic acid as crosslinkers, an investigation of the effect of crosslinker and catalyst concentrations, and a comparison of curing at 120°C and 180°C. The cotton was characterized by FTIR-ATR, the micrographs of treated samples were obtained by SEM and the weight add-on was calculated. The bactericidal properties were determined according to AATCC-147. The correlation between the coating process parameters and the antimicrobial efficacy was determined. The optimal combination leading to the highest weight add-on and the antimicrobial coating that was most durable to multiple detergent washes at an elevated temperature was the use of complexed triclosan grafted onto the cotton in the presence of tetracarboxylic acid, followed by curing at 180°C. The curing temperatures were 120°C (P=0.002) and 180°C (P=0.008), catalysts were 1 % and 2 % aluminium sulfate and sodium hypophosphite (P<0.001), and the crosslinkers were 5 % and 10 % glyoxal and butanetetracarboxylic acid (P<0.001); these parameters significantly enhanced the antimicrobial properties of the treated fabrics. The study showed that βCD did not have antimicrobial activity, while the βCD/triclosan-treated textile exhibited potential antimicrobial properties. Overall, the bactericidal activity of fabrics can be enhanced by using βCD/triclosan with 10 % butanetetracarboxylic acid as a cross-linker and 5 % sodium hypophosphite as a catalyst at a curing temperature of 180°C. 相似文献
106.
Mohamad Nurul Azman Mohammad Taib Wageeh Abdulhadi Yehye Nurhidayatullaili Muhd Julkapli Sharifah Bee O. A. Abdul Hamid 《Fibers and Polymers》2018,19(2):383-392
Novel acetylation process by substitution of acetic anhydride substitution with hydroxyl groups on nanocellulose (NCC) has been explored to increase its dispersion and interaction in nitrile butadiene (NBR) matrix. The crystallinity index was increased after modification when compared to unmodified NCC, but no significant different with increases of treatment time from 1 hour to 3 hours treatments proven by X-ray diffraction (XRD) results. The Fourier transform infra-red (FTIR) showed the existent of acetyl groups on surface of the NCC after treatment by existent of the peak 1736 cm-1 that attributed to carbonyl groups some peaks were observed at 1430, 1361 and 1248 cm-1 and confirmed on the acetylation process. The nuclear magnetic resonance (NMR) also show the present of acetyl groups by existent of the signal of proton methyl group at 1.90 ppm and new peaks at 5.42, 4.70 and 4.34 ppm, for all ACN samples. The thermal results by thermo gravimetric analysis (TGA) and differential scanning calorimetry (DSC) showed that the acetylated NCCs were 10 % more thermally stable. Transmission electron microscopic (TEM) results showed that no significant changes were observed due to the acetylation process. The results also showed well distributed of individual NCC after acetylation, this improvement was primarily attributed to uniform dispersion of the ACN-NCC and less aggregated occurred. Due to its hydrophobic characteristics, highly crystalline and nano size, ACN-NCC brought a significant improvement up to 25 % on the mechanical properties of nitrile butadiene (NBR) rubber composites. 相似文献
107.
A novel optical chemical sensor based on a transparent electrospun nanofibrous scaffold, composed of polycaprolactam (PA6) and 1,10-phenanthroline (Phen), deposited on a glass slide and impregnated with polyvinyl alcohol (PVA) was coupled with UV-vis spectrophotometry and used for colorimetric determination of ferrous ion (Fe2+) and ascorbic acid (AA). The electrospun nanofibers were characterized using scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FT-IR) techniques. The main factors affecting performance of the optical sensor (PA6-Phen/PVA@glass) including Phen dosage, pH of sample solution, electrospinning time, polymer solution flowrate, electrospinning voltage, and PVA amount were investigated and the related optimum values were obtained. The analytical merits of the sensor for quantitative determination of Fe2+ and ascorbic acid was evaluated. The limit of detection (LOD) and limit of quantification (LOQ) for Fe2+ were 1 and 3 μg mL-1, respectively. The linear dynamic range (LDR) was 3–150 μg mL-1 with the determination coefficient (R2) of 0.991. The relative standard deviation (RSD %, n=3) for a solution of 60 μg mL-1 was 5.4 %. For determination of AA, LOD and LOQ were obtained equal to 0.5 and 2 μg mL-1, respectively. The linear dynamic range was in the 2–200 μg mL-1 range with a R2 of 0.994. The RSD % at 100 μg mL-1, n=3) was equal to 7.0 %. The sensor was applied successfully to the detection of Fe(II) and AA in real water samples and aspirin tablets. 相似文献
108.
Wangbingfei Chen Weiwei Wang Xiaodong Ge Qufu Wei Reza Arman Ghiladi Qingqing Wang 《Fibers and Polymers》2018,19(8):1687-1693
Towards the goal of developing anti-infective textiles based on a photodynamic inactivation mechanism, here we present the design, dyeing procedure, characterization, substrate photooxidation studies, and antibacterial efficacy of methylene blue-dyed polyester fabrics, termed MB-polyester. Dye-uptake and apparent K/S (absorption and scattering coefficient) values as a function of MB concentration % (o.w.f) were determined, and were found to correlate. Photooxidation studies employing the model substrate 1,5-dihydroxynaphthalene (1,5-DHN) revealed that the MB-polyester fabrics were able to generate singlet oxygen in an illumination time-dependent manner. Antibacterial efficacy was evaluated against Staphylococcus aureus (ATCC-29213), with our best results achieving a 99.89 % (~3 log units) reduction in Colony-Forming Units (CFU)/mL after only 30 min illumination (Xenon lamp, 3500 mW/cm2, 420–780 nm). On the basis of these results with MB-polyester, we subsequently designed patterned dual-dyed polyester/cotton fabrics, wherein an alternating pattern of MBdyed polyester was combined with direct dyes-dyed cotton, and showed that their ability to sensitize singlet oxygen (1O2) in the photooxidation reaction of 1,5-DHN was maintained. Taken together, these findings suggest that MB is a suitable photosensitizer (PS) against S. aureus for the practical development of low-cost polyester-based antimicrobial textiles, and can potentially be used in the production of diverse form-patterned textiles that possess a photodynamic antimicrobial inactivation mechanism. 相似文献
109.
110.
Maryam Ahmadi Narges Damavandi Mohammad Reza Akbari Fatemeh Davami 《Iranian Biomedical Journal》2016,20(2):68-76
Mammalian expression systems, due to their capacity in post-translational modification, are preferred systems for biopharmaceutical protein production. Several recombinant protein systems have been introduced to the market, most of which are under clinical development. In spite of significant improvements such as cell line engineering, introducing novel expression methods, gene silencing and process development, expression level is unpredictable and unstable because of the random location of integration in the genome. Site-specific recombination techniques are capable of producing stable and high producer clonal cells; therefore, they are gaining more importance in the biopharmaceutical production. Site-specific recombination methods increase the recombinant protein production by specifically inserting a vector at a locus with specific expression trait. The present review focused on the latest developments in site-specific recombination techniques, their specific features and comparisons. 相似文献