4,801 research outputs found

    Phylogeographic analyses of an epiphytic foliose lichen show multiple dispersal events westward from the Hengduan Mountains of Yunnan into the Himalayas.

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    Lobaria pindarensis is an endemic species of the Himalayas and the Hengduan Mountains. Little information is available on the phylogeography genetics and colonization history of this species or how its distribution patterns changed in response to the orographic history of the Himalayas and Hengduan Mountains. Based on samples covering a major part of the species' distribution range, we used 443 newly generated sequences of nine loci for molecular coalescent analyses in order to reconstruct the evolutionary history of L. pindarensis, and to reconstruct the species' ancestral phylogeographic distributions using Bayesian binary MCMC analyses. The results suggest that current populations originated from the Yunnan region of the Hengduan Mountains in the middle Pliocene, and that the Himalayas of Bhutan were colonized by a lineage that diverged from Yunnan ca. 2.72 Ma. The analysis additionally indicates that the Nepal and Xizang areas of the Himalayas were colonized from Yunnan as well, and that there was later a second dispersal event from Yunnan to Bhutan. We conclude that the change in climate and habitat related to the continuous uplift of the Himalayas and the Hengduan Mountains in the late Pliocene and middle Pleistocene influenced the geographic distribution pattern of L. pindarensis

    Combination of capecitabine and ludartin inhibits colon cancer growth in mice

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    Purpose: To investigate the efficacy of capecitabine and ludartin in the treatment of colon cancer in mice.Methods: Mice model of colon cancer was used in this study. Quantitative real-time polymerase chain reaction (Qrt-PCR) was used to quantify the expression of vascular endothelial growth factor (VEGF) mRNA. Micro-vessel density was assessed using immunohistochemical analysis.Results: When administered separately, capecitabine and ludartin treatments significantly suppressed tumor growth in the mice model of colon cancer for 4 weeks, compared to control group. Coadministration of capecitabine and ludartin significantly inhibited tumor growth for 6 weeks (p < 0.05). Symptoms of colon cancer such as weight loss, skin discoloration and leukopenia were observed in untreated control group. However, these symptoms were completely absent in the group treated with combination of capecitabine and ludartin. The combined treatment also prevented colon cancer-induced increase in white blood cell (WBC) count, and increased median survival time of colon cancer mice from 38 to 55 days. Expression of VEGF in combination (capecitabine + ludartin) treatment group was significantly lower than in the control, i.e., untreated group (p ˂ 0.05). The combination treatment group also had significantly lower micro-vessel density in the tumor tissues, compared to the  ntreated control mice (p < 0.05).Conclusion: These results show that a combination treatment of capecitabine and ludartin effectively inhibits colon tumor growth and angiogenesis in mice via a mechanism involving suppression of VEGF expression. Thus, capecitabine and ludartin combination is a potentially  uitable treatment for colon cancer.Keywords: Colon cancer, Mice, Ludartin, Leukopenia, VEGF expression, Angiogenesi

    Improved performance of diatomite-based dental nanocomposite ceramics using layer-by-layer assembly

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    To fabricate high-strength diatomite-based ceramics for dental applications, the layer-by-layer technique was used to coat diatomite particles with cationic [poly(allylamine hydrochloride)] and anionic [poly(sodium 4-styrenesulfonate)] polymers to improve the dispersion and adsorption of positively charged nano-ZrO2 (zirconia) as a reinforcing agent. The modified diatomite particles had reduced particle size, narrower size distribution, and were well dispersed, with good adsorption of nano-ZrO2. To determine the optimum addition levels for nano-ZrO2, ceramics containing 0, 20, 25, 30, and 35 wt% nano-ZrO2 were sintered and characterized by the three-point bending test and microhardness test. In addition to scanning electron microscopy, propagation phase-contrast synchrotron X-ray microtomography was used to examine the internal structure of the ceramics. The addition of 30 wt% nano-ZrO2 resulted in the highest flexural strength and fracture toughness with reduced porosity. Shear bond strength between the core and veneer of our diatomite ceramics and the most widely used dental ceramics were compared; the shear bond strength value for the diatomite-based ceramics was found to be significantly higher than for other groups (P < 0.05). Our results show that diatomite-based nanocomposite ceramics are good potential candidates for ceramic-based dental materials

    Rapid screening mutations of first-line-drug-resistant genes in Mycobacterium tuberculosis strains by allele-specific real-time quantitative PCR

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    Tuberculosis (TB) is a worldwide health, economic, and social burden, especially in developing countries. Drug-resistant TB is the most serious type of this burden. Thus, it is necessary to screen drug-resistant mutations by using a simple and rapid detection method. A total of 32 pairs of allele-specific PCR (AS-PCR) primers were designed to screen mutation and/or wild-type alleles of 16 variations in four first-line drug-resistant genes (katG, rpoB, rpsL, and embB) of TB strains. A pair of primers was designed to amplify 16S rRNA gene and to verify successful amplification. Subsequently, we tested the specificity and sensitivity of these AS-PCR primers. The optimized condition of these AS-PCR primers was first confirmed. All mutations could be screened in general AS-PCR, but only 13 of 16 variations were intuitively investigated by using real-time quantitative PCR (qPCR) and AS-PCR primers. The results of specificity assay suggested that the AS-PCR primers with mutation and/or wildtype alleles could successfully amplify the corresponding allele under optimized PCR conditions. The sensitivity of nine pairs of primers was 500 copy numbers, and the other seven pairs of primers could successfully amplify correct fragments with a template comprising 103 or 104 copy numbers template. An optimized AS-qPCR was established to screen drug-resistant mutations in TB strains with high specificity and sensitivity

    Application of diaminium iodides in binary ionic liquid electrolytes for dye-sensitized solar cells

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    N-(2-hydroxyethyl)ethylenediaminium iodides (HEEDAIs) and N-(2-hydroxyethyl)piperazinium iodides (HEPIs) were synthesized, and their thermal properties were analysed. The influence of HEEDAI and HEPI on I 3 − /I − redox behavior in binary ionic liquid was investigated. The result revealed that HEEDAI can suppress the recombination between I 3 − and the injected electrons in TiO 2 conduction band and be used as the alternative of 4-tert-butylpyridine in the electrolyte of dye-sensitized solar cells. The electrolyte C, 0.15 mol·L −1 I 2 , HEEDAI and MPII with mass ratio of 1 : 4, gave the short-circuit photocurrent density of 9.36 mA·cm −2 , open-circuit photovoltage of 0.67 V, fill factor of 0.52, and the corresponding photoelectric conversion efficiency of 3.24% at the illumination (air mass 1.5, 100 mW·cm −2 , active area 0.25 cm 2 )

    Leukotriene B4, administered via intracerebroventricular injection, attenuates the antigen-induced asthmatic response in sensitized guinea pigs

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    <p>Abstract</p> <p>Background</p> <p>Despite intensive studies focused on the pathophysiology of asthmatic inflammation, little is known about how cross-talk between neuroendocrine and immune systems regulates the inflammatory response during an asthmatic attack. We recently showed corresponding changes of cytokines and leukotriene B<sub>4 </sub>(LTB<sub>4</sub>) in brain and lung tissues of antigen-challenged asthmatic rats. Here, we investigated how LTB<sub>4 </sub>interacts with the neuroendocrine-immune system in regulating antigen-induced asthmatic responses in sensitized guinea pigs.</p> <p>Methods</p> <p>Ovalbumin-sensitized guinea pigs were challenged by inhalation of antigen. Vehicle, LTB<sub>4 </sub>or U75302 (a selective LTB<sub>4 </sub>BLT1 receptor inhibitor) was given via intracerebroventricular injection (i.c.v.) 30 min before challenge. Airway contraction response was evaluated using Penh values before and after antigen challenge. The inflammatory response in lung tissue was evaluated 24 h after challenge. The LTB<sub>4 </sub>content of lung and brain homogenate preparations was detected by reversed phase high-performance liquid chromatography (RP-HPLC). Plasma levels of adrenocorticotropic hormone (ACTH) and corticosterone (CORT) were measured using ELISA kits.</p> <p>Results</p> <p>Antigen challenge impaired pulmonary function and increased inflammatory cell infiltration in lung tissue. These responses could be significantly suppressed by LTB<sub>4</sub>, 30 ng i.c.v., in ovalbumin-sensitized guinea pigs. LTB<sub>4 </sub>content of lung and brain homogenates from antigen-challenged guinea pigs was significantly increased. In addition, administration of LTB<sub>4 </sub>via i.c.v. markedly increased CORT and ACTH level in plasma before antigen challenge, and there were further increases in CORT and ACTH levels in plasma after antigen challenge. U75302, 100 ng i.c.v., completely blocked the effects of LTB<sub>4</sub>. In addition, U75302, 100 ng via i.c.v. injection, markedly decreased LTB<sub>4 </sub>content in lung homogenates, but not in brain homogenates.</p> <p>Conclusions</p> <p>Increased LTB<sub>4 </sub>levels in brain during asthmatic attacks down-regulates airway contraction response and inflammation through the BLT1 receptor. Stimulation of the hypothalamic-pituitary-adrenal axis by LTB<sub>4 </sub>may result in an increase in systemic glucocorticoids which, in turn, would feed back to suppress the asthmatic response.</p

    排卵功能障碍性不孕症患者的中医五态人格及焦虑分析

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    Objective: Finding out the relationship between five-pattern personality and anxiety 、depression characteristics of the DOI patients. Methods: 200 DOI patients were selected in the Infertility Specialist of Guangzhou Liwan District Hospital of Chinese Medicine,at the same time, researchers choose normal women as controls. Respondents filled in the Five-pattern Personality Scales、SAS、SDS and general information questionnaire. Results: The proportion of shaoyin personality of the DOI patients(50%) is significantly higher than the normal women(22%). And no yin and yang personality was observed in patients with DOI. The SAS and SDS score of the DOI patients, listed in descending order, is as follow, taiyin personality、shaoyin personality、taiyang personality、shaoyang personality、yin and yang personality. Conclusion: The main five-pattern personality of DOI is shaoyin personality. The patients of the taiyin and shaoyin personality are more likely to have the characteristics of anxiety and depression.目的  探究排卵功能障碍性不孕症患者不同中医五态人格类型与焦虑、抑郁情绪的关联性。方法  确诊为排卵功能障碍性不孕症患者200例,同时在本院选择正常已育妇女作为对照组。采用《五态人格量表》、《焦虑自评量表(SAS)》、《抑郁自评量表(SDS)》及一般资料问卷进行调查。结果  排卵功能障碍性不孕症组中少阴型中医人格(50%)明显高于正常妇女组(22%),且没有出现阴阳平和型中医人格。不孕症组中太阳、少阳、少阴、太阴型中医人格的焦虑、抑郁总分4组间不全相等(P<0.001)。结论  排卵功能障碍性不孕症患者以少阴型中医人格为主,且太阴、少阴型中医人格的患者更易出现高焦虑、高抑郁

    Effects of electron beam radiation on trait mutation in azuki bean (Vigna angularisi)

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    Dry seeds of azuki bean (Vigna angularisi), Jingnong 6 and Hebei 801 varieties were irradiated by electron beam of 100, 300, 600, 700 and 900 Gy, respectively. Mutations of leaf shape and color, seed size and shape, trailing, more branching, dwarfing, early or late flowering time and high yield were created in M2 and M3 generations. There were richest variations in Jinnong 6 treated with 600 Gy. Heibei 801 was more sensitive to electron beam radiation than Jingnong 6; more mutation types were produced at 100, 300 and 600 Gy. The pod number per plant, seed number and yield per plant of Jinnong 6 displayed a strikingly negative correlation to radiation dose, while the pod length, pod width, and 100-seeds weight of progenies from Hebei 801 had a significantly negative correlation with the radiation dose, but pod number per plants showed significantly positive correlation. Few of the normal phenotype plant in M2 generation derived mutants of new leaf yellowing, narrow leaf, clustering flower and leaf, kidney or sword leaf in M3 generation. Mutants of kidney and sword leaf, early flowering time from M2 generation could be stably inherited in M3 generation.Keywords: Azuki bean (Vigna angularisi), electron beam radiation, trait mutatio
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