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排序方式: 共有572条查询结果,搜索用时 46 毫秒
21.
Moshe Shokeid 《Ethnic and racial studies》2013,36(2):198-212
Panethnicity ‐ the development of bridging organizations and the generalization of solidarity among ethnic subgroups ‐ is important theoretically because it focuses attention on ethnic change, and allows one to assess the relative importance of structural and cultural factors. In this article we present a framework for the study of panethnicity, generate research questions from this framework, and then test these questions by examining panethnicity within four broad racial/ethnic groupings: Asian Americans, Native Americans, Indo Americans and Latinos in the United States. A review of these four cases demonstrates that those groups with the greatest cross‐subgroup structural similarity (Asian Americans and Indo Americans) also display the greatest panethnic development and potential, despite their considerable cultural diversity. This suggests that structural factors are more important for understanding the development of panethnicity and, by extension, for understanding ethnic change generally. 相似文献
22.
Dispersed from a dry film into buffer (5 mM phosphate, 0.15 M NaCl, pH 7.4), the liponucleotide 1-β-d-arabinofuranosylcytosine 5′-diphosphate l-1,2-diacylglycerol (ara-CDPdiacylglycerol) spontaneously forms vesicles which are several microns in diameter and probably unilamellar. Their average size immediately begins to decrease, and after 2 h none can be seen in the light microscope. During 1–2 days in unstirred solutions at 25°C, the vesicles are transformed to spherical or nearly spherical micelles having an apparent partial specific volume of 0.835 ml·g?1, a maximum possible aggregation number of about 150, and an anhydrous radius of about 37 Å. The critical micelle concentration (CMC) is about 10 μM in buffer and 20 μM in distilled water, but micelle-monomer equilibration requires at least 1 week at a total concentration of 66 μM. This exceedingly slow equilibration is unique among reported detergents. The standard enthalpy and entropy of micellization are ?13 kJ·mol?1 and 87 J·mol?1·K?1, respectively. These values are within the range reported for other detergents. Sonication accelerates the vesicle-micelle transformation to 30 min. 相似文献
23.
《Bioorganic & medicinal chemistry letters》2020,30(13):127234
Here we report the synthesis and biological evaluation of a series of new 2-hydroxybenzylphosphonium salts (QPS) with antimicrobial and antitumor dual action. The most active compounds exhibit antimicrobial activity at a micromolar level against Gram-positive bacteria Sa (ATCC 209p and clinical isolates), Bc (1–2 μM) and fungi Tm and Ca, and induced no notable hemolysis at MIC. The change in nature of substituents of the same length led to a drastic change of biological activity. Self-assembly behavior of the octadecyl and oleyl derivatives was studied. QPS demonstrated self-assembly within the micromolar range with the formation of nanosized aggregates capable of the solubilizing hydrophobic probe. The synthesized phosphonium salts were tested for cytotoxicity. The most potent salt was active against on M−Hela cell line with IC50 on the level of doxorubicin and good selectivity. According to the cytofluorimetry analysis, the salts induced mitochondria-dependent apoptosis. 相似文献
24.
目的:探讨连续性血液净化在危重病人抢救中的应用及效果评价.方法:选取2010年1月~2012年11月我院收治的危重病人共26例,均采用连续性静脉-静脉血液滤过方法治疗,比较治疗前后的心脏血流动力学参数、肾功能与电解质的变化,观察全部患者治疗前后的临床症状改善情况及临床转归.结果:治疗前后的心率、中心静脉压、平均动脉压、心指数及心排出量差异均存在统计学意义(P<0.05);治疗后患者的血尿素氮、肌酐及钾水平均明显低于治疗前(P<0.05);治疗后患者的低血压、低血氧、昏迷改善率分别为66.67%、71.43%及62.50%;26例患者中死亡14例(53.85%),存活12例(46.15%).结论:连续性血液净化可以积极有效地治疗危重病患者,选择治疗的时候需要针对患者的情况进行综合判断和全面评估. 相似文献
25.
Oscar Zúñiga Alberto Olivares Manuel Rojo María Eugenia Chimal Fernando Díaz Iker Uriarte Carlos Rosas 《Journal of thermal biology》2013
Octopus mimus is an important cephalopod species in the coastal zone of Peru and Chile that is exposed to temperature variations from time to time due to El Niño/Southern Oscillation (ENSO) episodes when surface temperatures can reach 24 °C, 6 °C above typical temperatures in their habitat. The relationships between temperature and food availability are important factors that determine the recruitment of juveniles into the O. mimus population. The present study was to evaluate the relationship between thermoregulatory behavior and the age of paralarvae (summer population) to determine whether changes in this behavior occur during internal yolk consumption, making larvae more vulnerable to environmental temperature change. Oxygen consumption of paralarvae when 1–4 d old was determined to establish if respiration could be used to monitor the physiological changes that occur during yolk consumption. Horizontal thermal selection (17–30 °C), critical thermal maxima (CTMax), minima (CTMin), and oxygen consumption experiments were conducted with fasting paralarvae 1–4 d old at 20 °C. Preferred temperatures were dependent on the age of O. mimus paralarvae. One day old paralarvae selected a temperature 1.1 °C (23·4 °C) higher than 2 – 4 d old paralarvae (22·3 °C). The CTMax of paralarvae increased with age with values of 31·9±1.1 °C in 1-d-olds and 33·4±0.3 to 4-d-olds. CTMin also changed with age with low values in 2-d-old paralarvae (9.1±1·3 °C) and 11·9±0·9 °C in 4-d-old animals. The temperature tolerance range of paralarvae was age-dependent (TTD=difference between CTMax and CTMin) with higher values in 2 and 3 d old paralarvae (25–26 °C) as compared to 1 d old (23·1 °C) and 4 d old animals (22.7 °C). Oxygen consumption was not affected by the age of paralarvae, suggesting that mechanisms exist that compensate their metabloism until at least 4 d of age. The temperature tolerance range of a planktonic paralarvae of octopus species is presented for the first time. This range was dependent on the age of paralarvae, and so rendered the paralarvae more vunerable to a combination of high temperature and food deprivation during first days of life. Results in the present study provide evidence that O. mimus could be under ecological pressure if a climate change causes increased or decreased temperatures into their distribution range. 相似文献
26.
Abstract Structural aspects of BaB2O4 liquids have been investigated by the molecular dynamics simulation including the determination on the parameters of the interatomic potential applicable to BaB2O4 in both crystalline and molten states. The structure and physical properties of BaB2O4 crystals were successfully reproduced by the MD simulation for both α and β phases. The simulated interference function in the liquid state was also in good agreement with the experimental one. Several interesting features on the relaxation phenomena just after melting were reproduced by the simulation that the structure factors of simulated liquid maintain the characteristic features of the original crystal structure for more than 40ps after melting, and the variation of the number of rings formed by B-O bondings was found to increase after melting. 相似文献
27.
Sayali C. Ranade Sarfaraz Nawaz Arnab Chakrabarti Pierre Gressens Shyamala Mani 《Hormones and behavior》2013
"The goal of this study was to examine the effect of maternal iron deficiency on the developing hippocampus in order to define a developmental window for this effect, and to see whether iron deficiency causes changes in glucocorticoid levels. The study was carried out using pre-natal, post-natal, and pre + post-natal iron deficiency paradigm. Iron deficient pregnant dams and their pups displayed elevated corticosterone which, in turn, differentially affected glucocorticoid receptor (GR) expression in the CA1 and the dentate gyrus. Brain Derived Neurotrophic Factor (BDNF) was reduced in the hippocampi of pups following elevated corticosterone levels. Reduced neurogenesis at P7 was seen in pups born to iron deficient mothers, and these pups had reduced numbers of hippocampal pyramidal and granule cells as adults. Hippocampal subdivision volumes also were altered. The structural and molecular defects in the pups were correlated with radial arm maze performance; reference memory function was especially affected. Pups from dams that were iron deficient throughout pregnancy and lactation displayed the complete spectrum of defects, while pups from dams that were iron deficient only during pregnancy or during lactation displayed subsets of defects. These findings show that maternal iron deficiency is associated with altered levels of corticosterone and GR expression, and with spatial memory deficits in their pups." 相似文献
28.
S. de Campeneere L. O. Fiems J. L. de Boever J. M. Vanacker D. L. de Brabander 《Archives of animal nutrition》2013,67(1):1-12
The critical roughage part (CRP) of 2 diet types was determined in a cross-over design with 6 double-muscled and 6 normally conformated Belgian Blue bulls fitted with rumen cannulae. The roughage:concentrate ratio was lowered weekly until signs of a lack of physical structure were observed. For diet 1, consisting of maize silage and concentrates, the initial proportion of maize silage was 25% of DM but it decreased weekly with 5% units of DM. For the second diet, consisting of wheat straw and concentrate, 12% straw (DM basis) was provided during the first week and thereafter the proportion of straw decreased weekly with 3% units of DM. Several directly observable parameters (rumen pH, feed intake, bloat, faecal consistency) were evaluated weekly for each bull. Apart from these direct indicators of acidosis, also other parameters, whose results were only available after the end of the trial, were determined (volatile fatty acid profile, lactic acid concentration, chewing time). The roughage part between the part fed when signs of a lack of physical structure was first observed and the part that was fed the week before, was considered as the CRP. Most animals showed no acute signs of clinical acidosis (directly observable parameters) and finished the trial on a 100% concentrate diet. However, in sacco rumen DM-degradabilities of maize silage, grass silage and wheat grain was depressed considerably when low roughage diets were fed. Based on all observed parameters, the mean CRP was calculated to be 14.7% for diet 1 and 8.1% for diet 2. The beef type (double-muscled or not) had no influence on the CRP. 相似文献
29.
MS Y?ld?r?m S Ozyurek O? Tosun S Uzer N Gelecek 《Biology of sport / Institute of Sport》2016,33(1):89-94
The aim of this study was to compare the effects of static stretching, proprioceptive neuromuscular facilitation (PNF) stretching and Mulligan technique on hip flexion range of motion (ROM) in subjects with bilateral hamstring tightness. A total of 40 students (mean age: 21.5±1.3 years, mean body height: 172.8±8.2 cm, mean body mass index: 21.9±3.0 kg · m-2) with bilateral hamstring tightness were enrolled in this randomized trial, of whom 26 completed the study. Subjects were divided into 4 groups performing (I) typical static stretching, (II) PNF stretching, (III) Mulligan traction straight leg raise (TSLR) technique, (IV) no intervention. Hip flexion ROM was measured using a digital goniometer with the passive straight leg raise test before and after 4 weeks by two physiotherapists blinded to the groups. 52 extremities of 26 subjects were analyzed. Hip flexion ROM increased in all three intervention groups (p<0.05) but not in the no-intervention group after 4 weeks. A statistically significant change in initial–final assessment differences of hip flexion ROM was found between groups (p<0.001) in favour of PNF stretching and Mulligan TSLR technique in comparison to typical static stretching (p=0.016 and p=0.02, respectively). No significant difference was found between Mulligan TSLR technique and PNF stretching (p=0.920). The initial–final assessment difference of hip flexion ROM was similar in typical static stretching and no intervention (p=0.491). A 4-week stretching intervention is beneficial for increasing hip flexion ROM in bilateral hamstring tightness. However, PNF stretching and Mulligan TSLR technique are superior to typical static stretching. These two interventions can be alternatively used for stretching in hamstring tightness. 相似文献
30.
Kamichika Hayashi Takeshi Onda Hirona Honda Natsuo Ozawa Hitoshi Ohata Nobuo Takano Takahiko Shibahara 《Biochemistry and Biophysics Reports》2019
No effective, reliable treatment for stomatitis associated with cancer therapy has been established. This study focused on the its effectiveness of ozone nano-bubble water (ONBW) for the treatment of chemotherapy-induced stomatitis. Oral mucositis was induced in 14-week-old male Sprague-Dawley rats (N = 21). The animals were randomly divided into 3 groups: 7 without treatment (control); 7 treated with physiological salt solution (saline); and 7 treated with ONBW. Animals were weighed on Days 7, 9, 11, and 16. Stomatitis grade evaluation and bacterial count measurements were performed before rinsing in all animals 3, 5, and 10 days after acetic acid irritation (Days 9, 11, and 17 respectively). Weight loss after stomatitis creation was observed in all groups, with significant differences between the control and ONBW groups and between the saline and ONBW groups on Day 16. The stomatitis grade did not worsen during the experimental period in any group, with the lowest grades in the ONBW group on Days 11 and 16. Significant differences were identified between the control and ONBW groups and between the saline and ONBW groups on Days 11 and 16. Oral bacterial counts tended to decrease over time in all three groups, with the greatest decrease in the ONBW group, followed by the saline group. The decrease in the bacterial count was steepest in the ONBW group. Rinsing out the oral cavity with ONBW decreased bacterial counts and encouraged the healing of oral chemotherapy-induced stomatitis. ONBW may be an effective treatment for chemotherapy-induced stomatitis. 相似文献