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  • 1
    Electronic Resource
    Electronic Resource
    Syntheses of well-defined star-shaped poly(tetrahydrofuran) polyols by the ion-coupling method (1997)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 35 (1997), S. 3403-3408 
    Details
    ISSN: 0887-624X
    Keywords: star-shaped ; poly(THF) ; ion-coupling ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The prepoly(tetrahydrofuran) [poly(THF)] capped with hydroxyl and tetrahydrothiophenium groups was prepared using tetrahydrothiophene to terminate the living cationic polymerization of THF initiated by BF3·OEt2 and epichlorohydrin (ECH) at low conversion. Well-defined star-shaped poly(THF) polyols were synthesized by an ion-coupling reaction of the prepoly(THF) with tri- or tetrafunctional benzenecarboxylates, respectively, and this process proceeded by precipitation when the solution of the prepolymer in THF was added to an aqueous solution containing an excess of the corresponding coupling reagent. GPC studies showed that all of the carboxylate groups of every coupling reagent molecule took part in the ion-coupling reaction simultanously. This was confirmed by IR spectra. Almost all of the prepolymers were coupled to form star polymers after repeating the precipitation four times. 1H-NMR illustrated that both the star-shaped polymers and the prepolymers contained primary and secondary hydroxyl end groups. © 1997 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 35: 3403-3408, 1997
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
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    Paper (German National Licenses)
  • 2
    Electronic Resource
    Electronic Resource
    Cationic polymerization of 1,3-dioxepane in the presence of 2,2-bis(hydroxymethyl)butanol (1998)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 36 (1998), S. 2899-2903 
    Details
    ISSN: 0887-624X
    Keywords: cationic ring-opening polymerization ; poly(1,3-dioxepane) triol ; 2,2-bis(hydroxymethyl)butanol ; transacetalization ; activated monomer mechanism ; activated chain mechanism ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Cationic polymerization of 1,3-dioxepane (DOP) initiated by triflic acid was carried out in the presence of 2,2-bis(hydroxymethyl)butanol (BHMB). The structure and molecular weight of the products were characterized by GPC and NMR spectra. The results showed that molecular weight of the polyacetal obtained could be controlled by the initial mole ratio of DOP/BHMB. GPC showed that as the mole ratio of BHMB/DOP increased, the content of cyclic oligomers also increased. Proton, 13C and 2D HMQC-fg NMR demonstrated that no hydroxymethyl group of BHMB appeared as an end group. It was also illustrated by proton NMR that some BHMB units existed in cyclic oligomers. The mechanism of formation of cyclic oligomers was discussed. © 1998 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 36: 2899-2903, 1998
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
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    Paper (German National Licenses)
  • 3
    Electronic Resource
    Electronic Resource
    Gas permeabilities and permselectivity of photochemically crosslinked polyimides (1995)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 58 (1995), S. 485-489 
    Details
    ISSN: 0021-8995
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Photosensitive polyimide BTDA-3MPDA was modified by UV irradiation. The structure of UV-irradiated polyimides was investigated by FTIR and gel fraction measurements. The results showed that longer UV exposure time resulted in a higher extent of crosslinking. The gas permeabilities of hydrogen, oxygen and nitrogen through UV-irradiated polyimides were characterized in a temperature range from 30°C to 90°C. Photocrosslinking resulted in a sharp decline in gas permeability for hydrogen, oxygen, and nitrogen through polyimide in the initial stage of photocrosslinking. Then, as the crosslinked benzophenone percentage amounted to 28-38% for hydrogen, 17-31% for oxygen and 3-28% for nitrogen, the gas permeabilities showed another sharp decline. Gas permselectivity increased significantly with the progress of photocrosslinking, and it can be adjusted in a wide range by controlling the extent of crosslinking. Arrhenius plots of gas permeability for hydrogen and oxygen through UV-irradiated polyimides are straight lines; for nitrogen, however, change in the slope of the straight line is observed and activation energies for hydrogen and oxygen permeation show abrupt increases when crosslinked benzophenone percentage amounts to about 30%. UV-irradiated polyimides with simultaneous high gas permeability and permselectivity make them ideal candidate materials for gas separation. © 1995 John Wiley & Sons, Inc.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1995.070580301
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  • 4
    Electronic Resource
    Electronic Resource
    Study on the cationic polymerization mechanism of 1,3-dioxepane in the presence of ethylene glycol (1997)
    Weinheim : Wiley-Blackwell
    Macromolecular Chemistry and Physics 198 (1997), S. 2613-2622 
    Details
    ISSN: 1022-1352
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The cationic polymerization of 1,3-dioxepane (DOP) initiated with trifluoromethanesulfonic acid (I) in the presence of ethylene glycol (EG) was investigated. At sufficiently low concentration of the initiator ([I] 〉 0.01 mol/L vs. [EG] 〈 0.20 mol/L), the molecular weights of the obtained polyacetal oligodiols are controlled by the mole ratio of consumed DOP to initial EG. Gel-permeation chromatography studies revealed that the concentration of cyclic oligomers in the products are negligible. The mechanism of the polymerization was investigated by means of kinetic studies. The results showed that the polymerization proceeds according to the active chain end mechanism (ACF) in combination with the activated monomer mechanism (AM); thus the cyclic oligomer in the obtained polymer is reduced, and intermolecular chain transfer to EG in ACE is dominant. It was also demonstrated that as [DOP]2[I]/[EG] decreases the contribution of ACE to the polymerization decreases and that of AM increases. In addition, 1H and 13C NMR data illustrated that each macromolecule of polyDOP oligodiols contained one EG unit on average and that no EG end groups exist.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/macp.1997.021980819
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  • 5
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    Amyloid beta1-42 (Aβ42) up-regulates the expression of sortilin via the p75NTR/RhoA signaling pathway (2013)
    Wiley-Blackwell
    Details
    Publication Date: 2013-07-31
    Description: Sortilin, a Golgi sorting protein and a member of the VPS10P family, is the co-receptor for proneurotrophins, regulates protein trafficking, targets proteins to lysosomes and regulates low density lipoprotein metabolism. The aim of this study was to investigate the expression and regulation of sortilin in Alzheimer's disease (AD). A significantly increased level of sortilin was found in human AD brain and in the brains of 6-month-old APPswe/PS1dE9 transgenic mice. Aβ 42 enhanced the protein and mRNA expression levels of sortilin in a dose- and time-dependent manner in SH-SY5Y APP695 cells, but had no effect on sorLA. In addition, proBDNF also significantly increased the protein and mRNA expression of sortilin in these cells. The recombinant extracellular domain of p75 NTR (P75ECD-FC), or the antibody against the extracellular domain of p75 NTR , blocked the upregulation of sortilin induced by Aβ, suggesting that Aβ 42 increased the expression level of sortilin and mRNA in SH-SY5Y via the p75 NTR receptor. Inhibition of ROCK, but not JNK, suppressed constitutive and Aβ 42 -induced expression of sortilin. In conclusion, this study shows that sortilin expression is increased in the AD brain in human and mice and that Aβ 42 oligomer increases sortilin gene and protein expression through p75 NTR and RhoA signaling pathways, suggesting a potential physiological interaction of Aβ 42 and sortilin in Alzheimer's disease. This article is protected by copyright. All rights reserved.
    Print ISSN: 0022-3042
    Electronic ISSN: 1471-4159
    Topics: Medicine
    Published by Wiley-Blackwell on behalf of The International Society for Neurochemistry.
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  • 6
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    Association between CHEK2 H371Y mutation and response to neoadjuvant chemotherapy in women with breast cancer (2015)
    BioMed Central
    Details
    Publication Date: 2015-03-29
    Description: Background: Our previous study suggested that the recurrent CHEK2 H371Y mutation is a novel pathogenic mutation that confers an increased risk of breast cancer. The purpose of this study was to investigate whether breast cancer patients with CHEK2 H371Y mutation were more likely to respond to neoadjuvant chemotherapy. Methods: We screened a cohort of 2334 Chinese women with operable primary breast cancer who received a neoadjuvant chemotherapy regimen for CHEK2 H371Y germline mutations. Pathologic complete response (pCR) was defined as the absence of tumor cells in the breast after the completion of neoadjuvant chemotherapy. Results: Thirty-nine patients (1.7%) with CHEK2 H371Y germline mutation were identified in this cohort of 2334 patients. CHEK2 H371Y mutation carriers had a significantly higher pCR rate than non-carriers (33.3% versus 19.5%, P = 0.031) in the entire study population, and CHEK2 H371Y mutation-positive status remained an independent favorable predictor of pCR in a multivariate analysis (odds ratio [OR] = 3.01; 95% confidence interval [CI]: 1.34- 6.78, P = 0.008). CHEK2 H371Y carriers had a slightly worse distant recurrence-free survival than non-carriers (adjusted hazard ratio [HR] =1.24, 95% CI: 0.59-2.63). Conclusions: CHEK2 H371Y mutation carriers are more likely to respond to neoadjuvant chemotherapy than are non-carriers.
    Electronic ISSN: 1471-2407
    Topics: Medicine
    Published by BioMed Central
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  • 7
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    Effects of dietary omega-3/omega-6 fatty acid ratios on reproduction in the young breeder rooster (2015)
    BioMed Central
    Details
    Publication Date: 2015-03-23
    Description: Background: Polyunsaturated fatty acids (PUFAs) are necessary for the body's metabolism, growth and development. Although PUFAs play an important role in the regulation of reproduction, their role in testis development in the rooster is unknown. The present study was conducted to investigate the effects of omega-3/omega-6 (n-3/n-6, PUFAs) ratios on reproductive performance in young breeder roosters. Plasma levels of reproductive hormones, testis development, and reproductive hormone receptor and StAR mRNA expression were also assessed. Results: Although PUFAs (n-3/n-6: 1/4.15) had no significant effect on the testis index (P 〉 0.05), the spermatogonial development and germ cell layers were increased. Moreover, serum levels of hormones (GnRH, FSH, LH and T) on day 35 were also significantly increased by PUFAs (n-3/n-6: 1/4.15). To investigate whether PUFAs regulate the expression of hormone receptors and StAR, real time-PCR was used to measure GnRHR, FSHR, LHR and StAR mRNA levels. PUFAs significantly increased the mRNA levels of all of these genes. Conclusions: These results indicate that PUFAs enhance the reproductive performance of young roosters by increasing hormone secretion and function, the latter by up-regulating receptor expression. These findings provide a sound basis for a balanced n-3/n-6 PUFA ratio being beneficial to young rooster reproduction.
    Electronic ISSN: 1746-6148
    Topics: Medicine
    Published by BioMed Central
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  • 8
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    Characterization and analysis of an infectious bronchitis virus strain isolated from southern China in 2013 (2016)
    BioMed Central
    Details
    Publication Date: 2016-03-11
    Description: Infectious bronchitis is a severe disease caused by infectious bronchitis virus (IBV) that affects fowl flocks worldwide. The understanding of the mechanisms involved in IBV evolution and variation would provi...
    Electronic ISSN: 1743-422X
    Topics: Medicine
    Published by BioMed Central
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  • 9
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    Genetic analysis and molecular characterization of Chinese sesame (Sesamum indicum L.) cultivars using Insertion-Deletion (InDel) and Simple Sequence Repeat (SSR) markers (2014)
    BioMed Central
    Details
    Publication Date: 2014-03-20
    Description: Background: Sesame is an important and ancient oil crop in tropical and subtropical areas. China is one of the most important sesame producing countries with many germplasm accessions and excellent cultivars. Domestication and modern plant breeding have presumably narrowed the genetic basis of cultivated sesame. Several modern sesame cultivars were bred with a limited number of landrace cultivars in their pedigree. The genetic variation was subsequently reduced by genetic drift and selection. Characterization of genetic diversity of these cultivars by molecular markers is of great value to assist parental line selection and breeding strategy design. Results: Three hundred and forty nine simple sequence repeat (SSR) and 79 insertion-deletion (InDel) markers were developed from cDNA library and reduced-representation sequencing of a sesame cultivar Zhongzhi 14, respectively. Combined with previously published SSR markers, 88 polymorphic markers were used to assess the genetic diversity, phylogenetic relationships, population structure, and allele distribution among 130 Chinese sesame accessions including 82 cultivars, 44 landraces and 4 wild germplasm accessions. A total of 325 alleles were detected, with the average gene diversity of 0.432. Model-based structure analysis revealed the presence of five subgroups belonging to two main groups, which were consistent with the results from principal coordinate analysis (PCA), phylogenetic clustering and analysis of molecular variance (AMOVA). Several missing or unique alleles were identified from particular types, subgroups or families, even though they share one or both parental/progenitor lines. Conclusions: This report presented a by far most comprehensive characterization of the molecular and genetic diversity of sesame cultivars in China. InDels are more polymorphic than SSRs, but their ability for deciphering genetic diversity compared to the later. Improved sesame cultivars have narrower genetic basis than landraces, reflecting the effect of genetic drift or selection during breeding processes. Comparative analysis of allele distribution revealed genetic divergence between improved cultivars and landraces, as well as between cultivars released in different years. These results will be useful for assessing cultivars and for marker-assisted breeding in sesame.
    Electronic ISSN: 1471-2156
    Topics: Biology
    Published by BioMed Central
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  • 10
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    A New Instrument for Testing Wind Erosion by Soil Surface Shape Change (2011)
    Hindawi
    Details
    Publication Date: 2011-03-02
    Description: Wind erosion, a primary cause of soil degeneration, is a problem in arid and semiarid areas throughout the world. Many methods are available to study soil erosion, but there is no an effective method for making quantitative measurements in the field. To solve this problem, we have developed a new instrument that can measure the change in the shape of the soil surface, allowing quick quantification of wind erosion. In this paper, the construction and principle of the new instrument are described. Field experiments are carried out using the instrument, and the data are analyzed. The erosion depth is found to vary by 11% compared to the average for measurement areas ranging from 30×30 cm2 to 10×10 cm2. The results show that the instrument is convenient and reliable for quantitatively measuring wind erosion in the field.
    Print ISSN: 1687-7667
    Electronic ISSN: 1687-7675
    Topics: Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Published by Hindawi
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