954 resultados para 4-23
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采用乙酸地衣红染色技术(Acetic orcein staining technique)较系统地研究了长牡蛎 Crassostrea gigas (Thunberg)三倍体产生的卵子在受精且第一极体释放受抑制后的减数分裂过及染色体的分离行为以阐明可存活四倍体的产生体的机制。用浓度为0.5 mg/L的细胞松驰素B (CB)处理受卵以抑制其第一极体的释放。在观察到个别受精卵出现第一极体时开始CB处理,持续至对照组中50%的受精卵出现的第一极体。对处理组和对照组的受精卵从受精后隔5分钟取样一次,用卡诺氏液(Carnoy's fixative, 冰醋酸和甲醇按1:3的体积比充分混合)固家样品。采用0.5%的乙酸-地衣红染料进行受精卵的染色,而后压片观察受精卵染色体行为。长牡蛎三倍体产生的卵子,中期I同源染色体构型呈现单价体(Univalents),二价体(Bivalents)、三价体(Trivalents)以及大于三价体的多价体(Multivalents)混合出更的特征。在第一极体释放受抑制的受精卵的第二次减数分裂过程中,可确认四种染色体分离类型:三极分离(Tripolar segregation) (54.5%)、联合二极分离(United bipolar segregation) (12%)、独立二级分离(Incomplete united bipolar segregation)(4%)。其余卵子的染色体分离行为(23%)不规律,呈现不同程度的紊乱,但总体看来介于上述四种分离类型之间。此外,某些特定的独立二级也可能是四位体形成的最主要的细胞遗传学体制。此外,某些特定的独立二极分离也可能产生四倍体。轻细胞体驰素B 处理的受精卵的减数分裂过程具有显著的不同步性,表现在三个方面:第一,在两个重复组之间,即两个雌体之间,存在第二次减数分裂的时间进程的不同步性;第二,同一个雌体产生的卵子之间的发育速度不同步性,表现为不同的卵子进入第一次减数分裂的时间不同;第三,同一卵子内的染色体之间,其行为有时存在的不同步性。另外,探讨了中心类在支配第二减数分裂时各种染色体分离行为的可能机制。以长牡蛎二倍体与近江牡蛎二倍体的染交作为对照,探讨了能长牡蛎四倍体与近江牡蛎二倍体杂并诱导异源三倍体的可行性。长牡蛎Crassostrea gigas (Thunberg)四倍体和二倍体与近江牡蛎Crassostrea rivularis (Gould)二倍体的杂交以及相应的对照组共进行了三批重复实验,杂交实验采用高密度的精子。研究结果表明,自交组平均受精率依次为94%(GG)、77% (RR),88% (G/GG)和85% (GG/G)。双方差分析(ANOVA)表明,各自交组之间受精率没有显著差异(F=3.118, P=0.132)。在杂交组,直接授精后180分钟,尚未观察到受精迹象,因而无法估计受精率。授精后48小时的孵化率各组之间差异很大,并经双方差分析(ANOVA)表明存在显著性差异,(F=3.188, P=0.018)。其中GGR和RGG组的孵化率相近似,产生的幼虫数量明显少于对照组。在四种类型的杂交实验中,二倍体C. gigas (雌体) * 二倍体 C. rivularis (雌体)(GR)早最成功的。虽基GR组幼虫的生长率低于对照组,但其存活率接近于对照组。长牡蛎四倍体与近江牡蛎二倍体杂交组(GR),在授精后两天的孵化率较低,但幼虫的生长状况与对照组接近。另外两个杂交组,即近江牡蛎二倍体与长牡蛎四倍体(RGG),二倍体近江牡蛎江与二倍体长牡蛎(RG),授精后两天的孵化率很低,幼虫生长得缓慢。三个重复组的GR杂交组和一个重复组的GGR杂交组获得稚贝。聚合酶链式反应/限制性酶切片段长度的多态性(PCR/PFLP)检支分析结果证实这些稚贝均是杂交种;流式细胞术分析结果证明GGR获得的稚贝是三倍体,从而证明获得了长牡蛎与近江牡蛎的异源三倍体。有迹象表明三倍体与二倍体杂交种之间(GGR对GR)存在生长上的差异。首先,GGR的眼点幼虫大约比GR组早出现5-7天即仅次于对照组GG,G/GG,和GG/G;第二,尽管仅获得少量GGR幼贝,这些幼贝在授精后90天的大小显著大于GR组的个体。在RGG和RG组中,幼虫没能存活到眼点幼点阶段。细胞学检查结果表明,杂交组的绝大多数卵子发育停滞在第一次减数分裂中期(Metaphase I),这一过程至少持续到授精后180分钟。仅有2%的GGR 组的卵子在授精后180分钟进入第一次减数分裂后期)(Anaphase I). 而在此时期,GR,RGG和RG组的卵子中,仍只观察到10第二价体(Bivalents).
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通过对青海省8个农气观测站的土壤表面始冻期和解冻期连续观测资料的分析,结果表明:青海各地土壤表面始冻期和解冻期存在着明显的地域差异,多数站点的封冻期呈现出缩短的趋势,互助、德令哈略有延长.始冻期变化受气候变化的明显影响,当3-9月平均气温升高1℃,除贵德、诺木洪、互助站响应不明显外,其余站点的始冻期推迟1.5~7.5d,平均推迟2.3d;当3-9月日照时数增多10h,诺木洪地区始冻期提早0.5d,其余站点的响应不明显;当上年10月至当年2月平均气温升高1℃,除门源、德令哈站的解冻期响应不明显外,其余站点提前2~13d,平均提早2.5d;降水量增多10mm,除诺木洪推迟12d,其余站点推迟2~6d,平均推迟2.3d;当上年10月至当年2月平均气温升高1℃,封冻期日数除河南、门源、贵德响应不明显外,其余缩短2.4~23.1d,平均缩短1.8d.
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We measured the stable carbon isotope ratios for muscle of the upland buzzards (Buteo hemilasius), plateau pika (Ochotoma curzoniae), root vole (Microtus oeconomus), plateau zokor (Myospalax fontanierii) and passerine bird species at the Haibei Alpine Meadow Ecosystem Research Station (HAMERS), and provided diet information of upland buzzards with the measurement of stable carbon isotopes in tissues of these consumers. The results showed that δ~(13)C values of small mammals and passerine bird species ranged from -25.57‰ to -25.78‰ (n = 12), and from -24.81‰ to -22.51% (n = 43), respectively, δ~(13)C values of the upland buzzards ranged from -22.60‰ to -23.10‰ when food was not available. The difference in δ~(13)C values (2.88‰±0.31‰) between upland buzzards and small mammals was much larger than the differences reported previously, 1‰-2‰, and showed significant difference, while 1.31‰±0.34‰ between upland buzzard and passerine bird species did not differ from the previously reported trophic fractionation difference of 1‰-2‰. Estimation of trophic position indicated that upland buzzards stand at trophic position 4.23, far from that of small mammals, i.e., upland buzzards scarcely captured small mammals as food at the duration of food shortage. According to isotope mass balance model, small mammals contributed 7.89% to 35.04% of carbon to the food source of the upland buzzards, while passerine bird species contributed 64.96% to 92.11%. Upland buzzards turned to passerine bird species as food during times of shortage of small mammals. δ~(13)C value, a useful indicator of diet, indicates that the upland buzzards feed mainly on passerine bird species rather than small mammals due to "you are what you eat" when small mammal preys are becoming scarce.
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南山种羊场的育种方案是根据育种目标的4个选择标准,加权综合而形成。计算出的选择指数为:净毛质量+21.08;毛束长度+0.58;平均纤维直径-4.23;育成羊体质量+1.47。估测该方案每世代遗传进展为1.6~2.1,选择指数标准差依MOET功率而定,与传统的育种改良方案(每世代遗传进展约为选择指数标准差)相比非常有益。
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大平掌矿区细碧岩-石英角斑岩建造为典型的双峰式火山岩组合,缺失SiO_2为52%~61%之间的中性火山岩。火山岩的TiO_2含量低及其它岩石化学特征、稀土元素地球化学特征均表明这套火山岩很可能形成于岛弧环境。不相容元素N-MORB标准化型式以Ba、Nd、Sm相对富集和Nb、Sr、Ti的相对亏损为特征,其中Ba 富集和Nb亏损更是岛弧火山作用的主要特征之一。大平掌矿区细碧岩具非常低的 Nb/Y(<0.15)和Zr/TiO_2(<0.01)比值,石英角斑岩的低Zr/TiO_2和Nb/Y特征以及Zr/Y比值(3.34~4.23)、(La/Yb)_N比值(0.47~2.50)变化范围都可以反映出火山岩形成于岛弧环境。大平掌火山岩的Sr、Nd同位素特征与世界上典型岛弧火山岩的Sr、Nd特征相似,其岩浆来源于亏损地幔,且经受地壳混染和(或)海水热液蚀变的影响。岩石中富含的放射成因铅也与岛弧环境密切相关。因此,大平掌铜多金属矿床的形成很可能受岛弧环境下的双峰式火山作用控制。
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BACKGROUND: The Notch signaling pathway is constitutively activated in human cutaneous melanoma to promote growth and aggressive metastatic potential of primary melanoma cells. Therefore, genetic variants in Notch pathway genes may affect the prognosis of cutaneous melanoma patients. METHODS: We identified 6,256 SNPs in 48 Notch genes in 858 cutaneous melanoma patients included in a previously published cutaneous melanoma genome-wide association study dataset. Multivariate and stepwise Cox proportional hazards regression and false-positive report probability corrections were performed to evaluate associations between putative functional SNPs and cutaneous melanoma disease-specific survival. Receiver operating characteristic curve was constructed, and area under the curve was used to assess the classification performance of the model. RESULTS: Four putative functional SNPs of Notch pathway genes had independent and joint predictive roles in survival of cutaneous melanoma patients. The most significant variant was NCOR2 rs2342924 T>C (adjusted HR, 2.71; 95% confidence interval, 1.73-4.23; Ptrend = 9.62 × 10(-7)), followed by NCSTN rs1124379 G>A, NCOR2 rs10846684 G>A, and MAML2 rs7953425 G>A (Ptrend = 0.005, 0.005, and 0.013, respectively). The receiver operating characteristic analysis revealed that area under the curve was significantly increased after adding the combined unfavorable genotype score to the model containing the known clinicopathologic factors. CONCLUSIONS: Our results suggest that SNPs in Notch pathway genes may be predictors of cutaneous melanoma disease-specific survival. IMPACT: Our discovery offers a translational potential for using genetic variants in Notch pathway genes as a genotype score of biomarkers for developing an improved prognostic assessment and personalized management of cutaneous melanoma patients.
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OBJECTIVE: To investigate the influence of culture with G-CSF GM-CSF and TNFalpha on neutrophil apoptosis, comparing neutrophils from SLE patients with rheumatoid arthritis (RA) patients and healthy control subjects. METHODS: Neutrophils were isolated from SLE (n= 10), RA (n= 10) and healthy control subjects (n= 10), and cultured with two different concentrations of G-CSF, GM-CSF and TNFalpha. Proportion of apoptotic neutrophils at T=0, T=2hrs and T=24hrs was measured using FITC-labelled annexinV and flow cytometry. RESULTS: Significantly more neutrophils were apoptotic at T=0 in the SLE subjects than in the other groups (median, range--Control 3.5% (0.3-7.9) SLE 9.5% (2.9-29.1) RA 3.0% (0.4-23.0) p
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The stars 51 Pegasi and tau Bootis show radial velocity variations that have been interpreted as resulting from companions with roughly Jovian mass and orbital periods of a few days. Gray and Gray & Hatzes reported that the radial velocity signal of 51 Peg is synchronous with variations in the shape of the line lambda 6253 Fe I; thus, they argue that the velocity signal arises not from a companion of planetary mass but from dynamic processes in the atmosphere of the star, possibly nonradial pulsations. Here we seek confirming evidence for line shape or strength variations in both 51 Peg and tau Boo, using R = 50,000 observations taken with the Advanced Fiber Optic Echelle. Because of our relatively low spectral resolution, we compare our observations with Gray's line bisector data by fitting observed line profiles to an expansion in terms of orthogonal (Hermite) functions. To obtain an accurate comparison, we model the emergent line profiles from rotating and pulsating stars, taking the instrumental point-spread function into account. We describe this modeling process in detail. We find no evidence for line profile or strength variations at the radial velocity period in either 51 Peg or in tau Boo. For 51 Peg, our upper limit for line shape variations with 4.23 day periodicity is small enough to exclude with 10 sigma confidence the bisector curvature signal reported by Gray & Hatzes; the bisector span and relative line depth signals reported by Gray are also not seen, but in this case with marginal (2 sigma ) confidence. We cannot, however, exclude pulsations as the source of 51 Peg's radial velocity variation because our models imply that line shape variations associated with pulsations should be much smaller than those computed by Gray & Hatzes; these smaller signals are below the detection limits both for Gray & Hatzes's data and for our own. tau Boo's large radial velocity amplitude and v sin i make it easier to test for pulsations in this star. Again we find no evidence for periodic line shape changes, at a level that rules out pulsations as the source of the radial velocity variability. We conclude that the planet hypothesis remains the most likely explanation for the existing data.
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There is an urgent need to replace the injection currently used for low molecular weight heparin (LMWH) multidose therapy with a non- or minimally invasive delivery approach. In this study, laser-engineered dissolving microneedle (DMN) arrays fabricated from aqueous blends of 15% w/w poly(methylvinylether-co-maleic anhydride) were used for the first time in active transdermal delivery of the LMWH nadroparin calcium (NC). Importantly, an array loading of 630 IU of NC was achieved without compromising the array mechanical strength or drug bioactivity. Application of NC-DMNs to dermatomed human skin (DHS) using the single-step 'poke and release' approach allowed permeation of approximately 10.6% of the total NC load over a 48-h study period. The cumulative amount of NC that permeated DHS at 24 h and 48 h attained 12.28 ± 4.23 IU/cm and 164.84 ± 8.47 IU/cm , respectively. Skin permeation of NC could be modulated by controlling the DMN array variables, such as MN length and array density as well as application force to meet various clinical requirements including adjustment for body mass and renal function. NC-loaded DMN offers great potential as a relatively low-cost functional delivery system for enhanced transdermal delivery of LMWH and other macromolecules. © 2012 Elsevier B.V. All rights reserved.
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Aim - To evaluate the reproducibility of the background fundus autofluorescence measurements obtained using a confocal scanning laser ophthalmoscope. Methods - 10 normal volunteers and 10 patients with retinal disease were included in the study. One eye per subject was chosen randomly. Five images of the same eye of each individual were obtained, after pupillary dilatation, by two investigators using a confocal scanning laser ophthalmoscope. Background fundus autofluorescence was measured at 7 degrees temporal to the fovea in normal volunteers and between 7 and 15 degrees temporal to the fovea in patients. Within session reproducibility of the measurements obtained by each investigator and interobserver reproducibility were evaluated. Results - For investigator 1 the median values of fundus autofluorescence obtained were 31.9 units for normal volunteers and 27.3 units for patients. The median largest difference in readings in normal volunteers was 5.7 units (range 1.4-13.5 units) and in patients 4.2 units (1.5-15.1 units). For investigator 2 the median values of fundus autofluorescence obtained were 28.9 units for normal volunteers and 27.4 units for patients. The median largest difference in readings in normal volunteers was 3.6 units (2.7-11.7 units), and in patients 4.1 units (1.5-9.3 units). The median interobserver difference in readings in normal volunteers was 3.3 units and for patients 6.6 units. The median greatest interobserver difference in measurements obtained for normal volunteers was 8.8 units (8.4-23.0 units) and for patients 11.1 units (7.1-40.8 units). Conclusion - Within session reproducibility of the measurements of background fundus autofluorescence was satisfactory. Although interobserver reproducibility was moderate, the variability of the measurements of fundus autofluorescence between observers appears to be small when compared with variation in fundus autofluorescence with age and disease.
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Glaucoma is a leading cause of blindness. It is a multifactorial condition, the risk factors for which are increasingly well defined from large-scale epidemiological studies. One risk factor that remains controversial is the presence of diabetes. It has been proposed that diabetic eyes are at greater risk of injury from external stressors, such as elevated intraocular pressure. Alternatively, diabetes may cause ganglion cell loss, which becomes additive to a glaucomatous ganglion cell injury. Several clinical trials have considered whether a link exists between diabetes and glaucoma. In this review, we outline these studies and consider the causes for their lack of concordant findings. We also review the biochemical and cellular similarities between the two conditions. Moreover, we review the available literature that attempts to answer the question of whether the presence of diabetes increases the risk of developing glaucoma. At present, laboratory studies provide robust evidence for an association between diabetes and glaucoma.
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There are strong links between childhood trauma and the risk of violence (Ford et al., 2007). Despite evidence that people with psychotic disorders are at a higher risk of violence than the general population (Witt et al., 2013) there have been few studies that have examined the trauma-violence link in this population (Spidel et al., 2010). This study explored the association between a history of childhood trauma (abuse, neglect and conflict-related trauma) and the risk of violence in adults with psychotic disorders. The strongest associations with the risk of violence were found for sexual abuse (r = .32, p < .05) and the impact of community conflict (r = .32, p < .05). An accumulative effect of trauma was found using a hierarchical regression (adjusted R2 = .14, F(2,37) = 4.23, p < .05). There are implications for applying models of violence to psychosis, risk assessment and treatment of people with psychotic disorders as well as informing trauma models and protective factors for children in conflict-affected regions.
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BACKGROUND AND PURPOSE: Stereotactic ablative radiotherapy (SABR) has become standard for inoperable early-stage non-small cell lung cancer (NSCLC). However, there is no randomized evidence demonstrating benefit over more fractionated radiotherapy. We compared accelerated hypofractionation (AH) and SABR using a propensity score-matched analysis.
MATERIALS AND METHODS: From 1997-2007, 119 patients (T1-3N0M0 NSCLC) were treated with AH (48-60Gy, 12-15 fractions). Prior to SABR, this represented our institutional standard. From 2008-2012, 192 patients (T1-3N0M0 NSCLC) were treated with SABR (48-52Gy, 4-5 fractions). A total of 114 patients (57 per cohort) were matched (1:1 ratio, caliper: 0.10) using propensity scores.
RESULTS: Median follow-up (range) for the AH cohort was 36.3 (2.5-109.1) months, while that for the SABR group was 32.5 (0.3-62.6)months. Three-year overall survival (OS) and local control (LC) rates were 49.5% vs. 72.4% [p=0.024; hazard ratio (HR): 2.33 (1.28, 4.23), p=0.006] and 71.9% vs. 89.3% [p=0.077; HR: 5.56 (1.53, 20.2), p=0.009], respectively. On multivariable analysis, tumour diameter and PET staging were predictive for OS, while the only predictive factor for LC was treatment cohort.
CONCLUSIONS: OS and LC were improved with SABR, although OS is more closely related to non-treatment factors. This represents one of the few studies comparing AH to SABR for early-stage lung cancer.
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A planta do amendoim é um prodígio da natureza. Conhecido pelo cidadão comum como um fruto seco semelhante às nozes, amêndoas, avelãs, pistácios e outros, o amendoim tem uma origem completamente diferente. Todos os outros crescem em árvores ou arbustos. O amendoim é produzido por uma planta herbácea, rasteira e ainda tem a particularidade de crescer enterrado no chão. Parece que a planta esconde aquele fruto extraordinário, saboroso e delicado. Fruto que é utilizado na alimentação humana, essencialmente torrado, mas que também serve como matériaprima para a extracção de óleo, para a produção de plástico ou no fabrico de rações para animais. Cultivado em muitos países, precisa de verões quentes e gosta de terrenos arenosos. Não sendo uma cultura importante em Portugal, chegou a sê-lo em Aljezur, zona onde encontrou tudo aquilo de que necessitava. Surgiu e desapareceu, como as suas flores amarelas que rapidamente se transformam em fruto escondido na terra.
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Tese apresentada para cumprimento dos requisitos necessários à obtenção do grau de Doutor em Ciências Musicais, na especialidade de Ensino e Psicologia da Música