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71.
Podsiadlo P Kaushik AK Arruda EM Waas AM Shim BS Xu J Nandivada H Pumplin BG Lahann J Ramamoorthy A Kotov NA 《Science (New York, N.Y.)》2007,318(5847):80-83
Nanoscale building blocks are individually exceptionally strong because they are close to ideal, defect-free materials. It is, however, difficult to retain the ideal properties in macroscale composites. Bottom-up assembly of a clay/polymer nanocomposite allowed for the preparation of a homogeneous, optically transparent material with planar orientation of the alumosilicate nanosheets. The stiffness and tensile strength of these multilayer composites are one order of magnitude greater than those of analogous nanocomposites at a processing temperature that is much lower than those of ceramic or polymer materials with similar characteristics. A high level of ordering of the nanoscale building blocks, combined with dense covalent and hydrogen bonding and stiffening of the polymer chains, leads to highly effective load transfer between nanosheets and the polymer. 相似文献
72.
全面推行学分制是高校教学改革的深化, 是教育和教学改革的一个发展阶段。但由于学分制所带来的思想教育、学生党建等新情况、新问题, 应值得所有教育者认真思考和研究的。本文围绕学分制实行后给学生党建工作带来的“四难”以及如何应对提出了一些理论和实践的思考。 相似文献
73.
Sullim Lee Geum Jin Kim Hyukbean Kwon Joo-Won Nam Ji Yun Baek Sang Hee Shim Hyukjae Choi Ki Sung Kang 《Marine drugs》2021,19(4)
Menopause, caused by decreases in estrogen production, results in symptoms such as facial flushing, vaginal atrophy, and osteoporosis. Although hormone replacement therapy is utilized to treat menopausal symptoms, it is associated with a risk of breast cancer development. We aimed to evaluate the estrogenic activities of Spartina anglica (SA) and its compounds and identify potential candidates for the treatment of estrogen reduction without the risk of breast cancer. We evaluated the estrogenic and anti-proliferative effects of extracts of SA and its compounds in MCF-7 breast cancer cells. We performed an uterotrophic assay using an immature female rat model. Among extracts of SA, belowground part (SA-bg-E50) had potent estrogenic activity. In the immature female rat model, the administration of SA-bg-E50 increased uterine weight compared with that in the normal group. Among the compounds isolated from SA, 1,3-di-O-trans-feruloyl-(-)-quinic acid (1) had significant estrogenic activity and induced phosphorylation at serine residues of estrogen receptor (ER)α. All extracts and compounds from SA did not increase MCF-7 cell proliferation. Compound 1 is expected to act as an ERα ligand and have estrogenic effects, without side effects, such as breast cancer development. 相似文献
74.
Joonseok?KohEmail author Ik?Soo?Kim Sung?Soo?Kim Woo?Sub?Shim Jae?Pil?Kim 《Fibers and Polymers》2004,5(1):44-51
Three bi-functional reactive dyes such as Bis(vinylsulphone) type, Bis(monochlorotriazine) type and Bis(mononicotinotriazine) type were applied to regular viscose rayon and new regenerated cellulosic fiber (enVix®) which was prepared from cellulose acetate fiber by the hydrolysis of acetyl groups, and their dyeing properties and fastness properties were compared.enVix exhibited better dyeability and fastness than regular viscose rayon and these results were also explained by the differences in the supramolecular structure of these two fibers. 相似文献
75.
enVix is a novel regenerated cellulosic fiber, which is prepared from cellulose diacetate fiber using environmentally friendly
manufacturing process. Vat dyeing properties of the enVix were investigated and compared with those of regular viscose rayon.
The enVix exhibited better dyeability than viscose rayon. The colour yields of vat dyes on the enVix were found to be dependent
on dyeing temperature as well as the amount of levelling agent and salt. Good build-up and good to excellent fastness properties
were obtained on the enVix fabric. 相似文献
76.
Poly(ethylene terephthalate) (PET) and poly(ethylene glycol) (PEG) copolymers cross-linked with pentaerythritol, a four-way
cross-linker, are prepared to compare their mechanical and shape memory properties with the one cross-linked by glycerol.
Composition of PEG and pentaerythritol is varied to search for the one with the best mechanical and shape memory properties.
The highest shape recovery rate is observed for the copolymer composed of 30 mol% PEG-200 and 2.5 mol% pentaerythritol. Four-way
cross-linking by pentaerythritol significantly improves shape recovery rate and retention of high shape recovery rate after
repeated use compared to the one cross-linked by glycerol, a three-way cross-linker, and difference and advantage of additional
cross-linking point are discussed. 相似文献
77.
SH. Golzar Adabi M. Ahbab A. R. Fani A. Hajbabaei N. Ceylan R. G. Cooper 《Journal of animal physiology and animal nutrition》2013,97(1):27-38
Lipids are an important nutritional component of the avian egg. A review of the literature was completed to determine the fatty acid compositions in egg yolk from some avian species. Additionally, the nutritional influence of lipid and lipoprotein content on the plasma of male participants during 30‐day feeding was discussed. The ostrich eggs had the highest unsaturated fatty acid and the lowest cholesterol content in relation to other avian species. Ostrich had a higher proportion of 18:3n‐3 (p < 0.01) compared with other species. Chicken yolk numerically contained much higher levels of 22:6n‐3 than those found in turkeys, quails and geese, but the amount of 22:6n‐3 in ostrich egg was lower by comparison with other species (p < 0.01). After the storage of eggs at the room temperature, there was a notable loss of vitamin E (vitE) in the yolks of all species and this decrease was marginal (p < 0.01) in ostrich compared with other species. There were significant (p < 0.05) increases in plasma low‐density lipoprotein (LDL) level in all male subjects. Plasma high‐density lipoprotein (HDL) level decreased (p < 0.05) only in men who were fed chicken or ostrich eggs daily. Consumption of different species’ eggs had no influence on the total male plasma cholesterol and triglyceride levels. LDL‐C:HDL‐C ratio increased (p < 0.05) after goose and turkey egg consumption. Consumption of one egg/month by healthy human subjects had no effect on serum total cholesterol and triglyceride. The LDL‐C:HDL‐C ratio (which is a strong predictor of coronary heart disease risk) increased, although non‐significantly, by consuming chicken, quail and ostrich eggs. 相似文献
78.
Junghyun Shim Olivier Panaud Clémentine Vitte Merlyn S. Mendioro Darshan S. Brar 《Euphytica》2010,176(2):269-279
Molecular markers have been successfully used in rice breeding however available markers based on Oryza
sativa sequences are not efficient to monitor alien introgression from distant genomes of Oryza. We developed O. minuta (2n = 48, BBCC)-specific clones comprising of 105 clones (266–715 bp) from the initial library composed of 1,920 clones against
O. sativa by representational difference analysis (RDA), a subtractive cloning method and validated through Southern blot hybridization.
Chromosomal location of O. minuta-specific clones was identified by hybridization with the genomic DNA of eight monosomic alien additional lines (MAALs). The
37 clones were located either on chromosomes 6, 7, or 12. Different hybridization patterns between O. minuta-specific clones and wild species such as O. punctata, O. officinalis, O. rhizomatis, O. australiensis, and O. ridleyi were observed indicating conservation of the O. minuta fragments across Oryza spp. A highly repetitive clone, OmSC45 hybridized with O. minuta and O. australiensis (EE), and was found in 6,500 and 9,000 copies, respectively, suggesting an independent and exponential amplification of the
fragment in both species during the evolution of Oryza. Hybridization of 105 O. minuta specific clones with BB- and CC-genome wild Oryza species resulted in the identification of 4 BB-genome-specific and 14 CC-genome-specific clones. OmSC45 was identified as a fragment of RIRE1, an LTR-retrotransposon. Furthermore this clone was introgressed from O. minuta into the advanced breeding lines of O. sativa. 相似文献
79.
Bo-Young Jeon Seung-Cheol Kim Sungmo Je Jeongyeon Kwak Jang-Eun Cho Jong-Tae Woo Sangkyo Seo Hang-Sub Shim Byoung-Ok Park Sung-Sik Lee Sang-Nae Cho 《Research in veterinary science》2010,88(3):390-393
An enzyme-linked immunosorbent assay (ELISA) using bulk tank milk samples was evaluated as a screening test for bovine tuberculosis (TB), a contagious chronic disease of cattle. An ELISA with MPB70, a major antigen of Mycobacterium bovis was performed using paired sets of milk and sera samples from 33 tuberculin-positive and 43 tuberculin-negative cattle. Anti-MPB70 antibodies were detected in milk samples and there was a significant correlation between seroreactivities of milk and sera samples (R2 = 0.83). Using the tuberculin skin test as the reference test, the sensitivities of ELISA using milk and sera samples were 87.8% and 81.8%, respectively, and the specificities were 97.7% and 100%, respectively.In the screening test using bulk tank milk samples from 931 dairy herds in Whasung, Gyeonggi-do, Korea, the positive rate for anti-MPB70 antibody was 4.5% (42/931) and the tuberculin-positive rate was 2.8% (26/931). Individual milk samples (n = 253) were collected from randomly selected 8 problematic and 3 negative herds (positive and negative in the screening test by MPB70 ELISA using bulk tank milk samples, respectively) and tested by MPB70 milk ELISA. In the problematic herds, positive rates were 10.5% (20/190) for anti-MPB70 antibodies in milk ELISA and 2.1% (4/190) in the tuberculin skin test. More than one dairy cows were positive by milk ELISA among the problematic herds, and all tuberculin-positive dairy cows were positive in the milk ELISA. Further, no positive cows were detected in negative herds both by milk ELISA and tuberculin skin test. These results suggest that an ELISA, using bulk tank milk samples, might be a potential efficient screening test for bovine TB of dairy cows. 相似文献
80.
Kang Bo Shim Seong Hyu Shin Ji Young Shon Shin Gu Kang Woon Ho Yang Sung Gi Heu 《Journal of Crop Science and Biotechnology》2016,19(2):151-155
Sesame (Sesamum indicum L.) is an important edible oil crop. Meteorological factors such as temperature, rainfall, and the amount of solar radiation determine the yield potential of sesame. To identify phenotypic diversity and to infer genotypic backgrounds in a collection of 250 sesame germplasm accessions, we classified the germplasm based on variation in morphological traits using principal component (PC) and cluster analysis. The sesame germplasm was grouped based on five PCs, which accounted for 82.3% of total variation. The first PC (PC1) was positively correlated with days to flowering, days to maturity, and number of capsules per plant, whereas the second PC (PC2) was negatively correlated with all characteristics except capsule-bearing stem length. The third component (PC3) was highly positively correlated with capsule length and plant height. We constructed a scatter diagram of the first two PCs (PC1 vs. PC2), revealing four distinct groups of eigenvectors. Most sesame germplasm was widely distributed among Groups I, II, III, and IV. Group III showed a wide range of distribution in the diagram. Otherwise, the distribution of the 250 germplasm accessions was more compact in a scatter diagram of PC1 vs. PC3 compared with PC1 vs. PC2. Groups I, II, III, and IV contained 142, 102, 2, and 3 sesame germplasm accessions, respectively. The two germplasm in Group III were collected from different regions, as were the three germplasm in Group IV. The results show that the distribution of sesame origin is wider than the regions examined in view of phenotypic diversity. 相似文献