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关键词： 类天疱疮   大疱性   天疱疮   光学相干断层扫描   诊断  

摘要： 目的 评估大疱性类天疱疮(BP)和天疱疮的光学相干断层扫描(OCT)成像特征.方法 收集2024年1-6月武汉市第一医院经临床表现、组织病理学和免疫学确诊的BP患者23例和天疱疮患者18例.采用OCT成像对41例患者皮损部位的水疱及其解剖位置(表皮内或表皮下)、疱内炎症细胞和纤维蛋白沉积、真皮上层的扩张血管以及皮损旁皮肤进行评估.结果 23例BP和18例天疱疮(寻常型12例,落叶型6例)患者中,男20例,女21例,发病年龄20～89岁.BP患者水疱OCT成像显示表皮下卵圆形至圆形液性暗区,内伴高折光炎症细胞和纤维蛋白沉积,真皮上层可见扩张的血管;天疱疮患者水疱OCT成像可见表皮内水疱伴少量炎症细胞;二者OCT特征与对应的组织病理特征表现相似.BP患者水疱内炎症细胞和纤维蛋白沉积的检出率(82.61％,19/23;60.87％,14/23)高于天疱疮患者(44.44％,8/18;11.11％,2/18;x2=6.54、10.51,P=0.011、0.001).疱旁正常皮肤OCT成像中,17.39％(8/46)的BP和25.00％(9/36)的天疱疮患者检测到亚临床裂隙.结论 OCT成像可精确定位BP和天疱疮患者的水疱和疱旁正常皮肤潜在的亚临床病变,有助于两种疾病的早期辅助诊断.

关键词： 铀铌合金   神经网络势函数   分子动力学   力学性能  

摘要： 铀铌合金在不同实验环境中呈现出复杂的晶体相和独特的力学性能,但原子尺度的相析出和形变损伤机制尚不清楚,其根本原因是缺乏支撑大尺度分子动力学模拟的精确铀铌合金原子相互作用势.本工作基于自主开发的神经网络势能函数及随机搜索方法,构建了覆盖全化学空间的铀铌合金第一性原理计算数据库,并基于神经网络框架建立了具有较高泛化性能和精度的铀铌二元体系机器学习势函数,其能量和力的测试平均绝对误差分别为5.6 meV/atom和0.095 eV/Å,可以精确地描述不同化学成分铀铌合金的晶体空间结构、状态方程及热力学参量.基于该势函数,我们实现了低温时效下铀铌合金相失稳分解过程的原子尺度模拟,初步阐明了 Nb析出相对其合金力学性能的影响及原子响应机制.

关键词： 渐近展开   渐近幂级数   三角函数   复合函数  

摘要： 本文研究了复合函数f(x)=h(g(x))的渐近幂级数,其中g(x)=∞∑n=0 bnx-n,bn∈ R,h为给定初等函数.当h是指数或对数函数时,复合函数的渐近展开已有结果.利用递推法,本文分别获得了七个三角函数复合的渐近展开式.作为应用,还给出了方程根的渐近展开.计算结果显示,我们的递推公式比拉格朗日逆定理的方法更有效率.

关键词： native poplar clone   arid valleys   venation structure   long-term water use efficiency   anatomical structure of leaves   (sic)(sic)(sic)(sic)(sic)(sic)(sic)   (sic)(sic)(sic)(sic)   (sic)(sic)(sic)(sic)   (sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)   (sic)(sic)(sic)(sic)(sic)(sic)  

摘要： The ecologically fragile arid valleys in western China have low afforestation survival rates, and the lack of adaptable superior variety is key to restricting forestry production and ecological restoration in this region. The native poplar trees are important germplasm resources in this region, with a wide range of taxa, rich genetic variations, and great potential for breeding and utilization. Six clones of native poplars were used in a field trial to investigate variations in survival, growth and adaptation to arid-warm and arid-hot valleys. In the arid-hot valley, clone Y1-2 exhibited the highest survival rate and growth condition, surpassing other clones, while clones B7-4 and P3-6 demonstrated superior survival and growth performance in the arid-warm valley. Clone B7-4 displayed the highest soluble sugar content in leaves across both habitats. Superoxide dismutase and ascorbate peroxidase activities, along with malondialdehyde content in leaves, were higher in the arid-hot valley for all clones compared with the arid-warm valley. Long-term water use efficiency, as indicated by delta 13C in leaves, was significantly higher for all clones in the arid-hot valley, particularly for H1-6, T3-2 and P3-6. Increases in upper epidermis thickness were observed in clones E1, B7-4 and P3-6, while Y1-2 exhibited a higher palisade parenchyma thickness (PT) in the arid-hot valley compared with the arid-warm valley. Vein densities were higher in leaves of clones E-1, B7-4, Y1-2 and P3-6 in both valleys compared with other clones, with B7-4 showing a significant increase in mean vein width in the arid-hot valley. In conclusion, the superior growth performance of clone B7-4 in the arid-warm valley may be attributed to its stronger osmotic adjustment and higher capacity to maintain water transportation through venation. The exceptional performance of clone Y1-2 in the arid-hot valley may be associated with its compact arrangement of PT, as well as its stronger capacity for hydraul

关键词： methods: data analysis   methods: observational   techniques: spectroscopic   planets and satellites: atmospheres   planets and satellites: individual: MASCARA-1b  

摘要： Aims. We present high-resolution emission spectroscopy observations of the ultra-hot Jupiter MASCARA-1b with CRIRES+ in the K-band, covering the post-eclipse phases of the planet's orbit. These observations complement previously published pre-eclipse data. Methods. The stellar and telluric features were removed from the data using the SYSREM algorithm, and the planetary signal was analysed with the cross-correlation technique. After confirming the presence of chemical species in our atmospheric model, we combined the pre- and post-eclipse datasets for a joint analysis. By employing a Bayesian retrieval framework with various parametrisations, this joint retrieval enabled us to constrain the spatially varying temperature-pressure (T-P) profile and the atmospheric carbon-to-oxygen (C/O) ratio. Results. We detected strong emission signatures of CO and H2O in the post-eclipse and the combined datasets. A well-mixed retrieval model results in a super-solar C/O, whereas allowing for vertically varying chemistry by incorporating a chemical model results in C/O values consistent with solar within approximate to 1.1 sigma. The retrieved parameters are not only consistent across the datasets but also across different chemical regimes. We did not identify any significant velocity shifts between the detected species or across the datasets that could otherwise serve as proxies for possible atmospheric dynamics. We also explored potential phase dependence through the model scaling factor and found no substantial changes in the atmospheric properties throughout the observed phases. Conclusions. Due to strong degeneracies between the temperature gradient and chemical abundances, our retrieved temperatures are broadly consistent with either a full redistribution of heat or strong day-night contrasts. While this complicates direct comparisons with recent Spitzer phase curve analyses suggesting inefficient recirculation, we find no clear evidence of spatial variation in the chemical o

摘要： 他们是暗夜的孤勇者,不但跋山涉水昼夜颠倒,有时还得听着蛙声一片坐半天"冷板凳",只为在林间水边不起眼的角落里寻觅一个个神秘的小小身影.他们就是蛙类猎人.