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Tomas Ojeda Deodato Radic Ligia Gargallo Daphne Boys 《Macromolecular chemistry and physics.》1980,181(11):2237-2244
Poly[4-(1,1,3,3-tetramethylbutyl)phenyl methacrylate] ( 1a ) was synthesized and its physicochemical properties were determined in the condensed phase and in dilute solution. The polymerization of 4-(1,1,3,3-tetramethylbutyl)phenyl methacrylate was carried out by radical mechanism in solution with 2,2′-azoisobutyronitrile as initiator. Several samples were characterized by their intrinsic viscosity, by osmometric measurements, differential scanning calorimetry, and X-ray diffraction. The viscometric behaviour of fractions of 1a was studied in good solvents and theta solvents, and the conformational parameters were calculated. Polymer 1a presents an unusual high rigidity in the chain. X-Ray diffraction of this polymer indicates a one-dimensional ordering of a mesomorphic type. 相似文献
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A novel papillomavirus was cloned from hyperkeratotic cutaneous lesions of a Persian domestic cat. The Felis domesticus papillomavirus (FdPV-1) genome counts 8300 bp and has a typical genome structure with an early region (E1, E2, E4, E6, E7), a late region (L1, L2), and a noncoding upstream regulatory region (URR or NCR1) between the end of L1 and the beginning of E6. The FdPV-1 also shows an unusual second noncoding region (NCR2) of 1.3 kb, situated between the end of E2 and the beginning of L2. This NCR2 is uniquely related to a similar region in the canine oral papillomavirus (COPV). Phylogenetic analysis places FdPV-1 together with COPV, the cottontail rabbit papillomavirus, human papillomavirus type 1 (HPV-1), and HPV-63 in the group of the benign cutaneous papillomaviruses. The position of FdPV-1 in the phylogenetic tree allows us to hypothesize that already in an early phase of the papillomavirus molecular evolution, a split occurred into viruses with a dual tropism primarily for cutaneous epithelia but also secondarily for mucosal surfaces, and viruses with a specific monotropism for mucosal surfaces. The close relationship between FdPV-1 and COPV, and between their Canidae and Felidae hosts, supports the hypothesis that papillomaviruses have speciated and coevolved together with their hosts throughout vertebrate evolution. A papillomavirus mutation rate of 0.73 to 0.96 x 10(-8) nucleotide substitutions per base per year was calculated. 相似文献
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Valledor AF 《Immunobiology》2005,210(2-4):127-132
Macrophages play essential roles in infection and resolution of inflammation. This review summarizes recent findings that suggest a relevant role for the nuclear receptor liver X receptor (LXR) in the evolution of immune responses. By exerting both positive and negative regulation of specific macrophage gene expression networks, LXRs display anti-inflammatory activities and promote macrophage survival in bacterial infection settings. Agonists that activate the LXR pathway may be used to enhance innate immunity to highly virulent pathogens that otherwise induce macrophage apoptosis as a means to subvert host immune defense. 相似文献
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This study aimed to quantify the patterns of drug use among a group of participants in the rave scene in Perth, Western Australia. Interviews were conducted with 83 people who had recently been to a 'rave'. The study incorporated a semi-structured qualitative interview and a structured quantitative questionnaire. This paper reports on the quantitative data collected concerning patterns of drug use in association with the last rave attended. Use of 'dance drugs' (ecstasy, amphetamines or LSD) was reported by 86.8% of the 76 respondents who had used at least one drug in association with their last rave. Nearly 80% of these had also used at least one other drug on this occasion (mean number used = 2.4). Cannabis and inhalants were the drugs most commonly combined with the 'dance drugs', several respondents used more than one 'dance drug' concurrently and 16.7% had used alcohol. It seems that a significant proportion of those using 'dance drugs' in association with raves and dance parties are mixing these drugs with other substances despite harm reduction advice to the contrary. The need for more research in this area is discussed. 相似文献
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