4种香茶菜属植物微性状特征研究

目的 研究香茶菜及同属植物微性状鉴别特征。方法 采用500万像素电子摄像目镜,应用景深合成技术合成微性状鉴别图片,观察4种香茶菜属植物的新鲜及干燥叶片的微性状特征。结果 在叶尖突起程度、毛茸的长短与分布方面,4种香茶菜属植物叶片的微性状有明显不同：岐伞香茶菜和显脉香茶菜密被较长毛茸,叶尖极度突起或明显突起;香茶菜和大萼香茶菜稀被较短毛茸,毛茸多分布在叶脉、叶缘,叶尖微凹或突起。结论 微性状鉴别方法简便,可以区别香茶菜属不同植物。     

H5亚型禽流感病毒核蛋白基因重组质粒的构建及其在Hela细胞的瞬时表达

采用PCR技术从重组质粒pMel-NP扩增得到了禽流感病毒(AIV)A/Goose/Guang-dong/1/96(H5N1)株的核蛋白(NP)基因,将其亚克隆至真核表达载体pVAX1上。将提取的pVAX-NP阳性克隆转染Hela细胞,48 h后经间接免疫荧光试验和Western-blotting检测,NP基因在Hela细胞中已成功瞬时表达。表达产物的分子质量约为57 ku,它与H5N1亚型AIV多克隆抗血清有较好的免疫反应。     

禽多杀性巴氏杆菌C48-1成熟外膜蛋白H重组亚单位设苗免疫效果的研究

将融合表达禽多杀性巴氏杆菌成熟外膜蛋白H(OmpmH)的重组菌pGEX-ompmH/BL21大量培养,在最佳诱导条件下诱导表达,表达产物经蛋白酶剪切及亲和层析纯化,得到OmpmH基因的原核表达产物,将其与弗氏完全佐剂混合制成油乳剂亚单位疫苗,用该疫苗肌肉注射接种5周龄鸡,首免后每周采血检测抗体,二免后第2周用10 LD50禽多杀性巴氏杆菌强毒菌株C48-1进行攻击.结果显示,OmpmH具有良好的免疫原性,能诱导鸡体产生特异性抗体,可抵抗强毒菌株C48-1的致死性攻击,免疫效果优于禽多杀性巴氏杆菌弱毒疫苗.     

徐迟和梭罗:以《瓦尔登湖》的翻译为中心

徐迟与梭罗《瓦尔登湖》之间的情缘持续了几十年时间。徐迟初译和复译《瓦尔登湖》的时间跨度极大,其间先后经历了新中国的成立、建国后的一系列政治运动和1980年以后的改革开放。徐迟对梭罗《瓦尔登湖》的翻译认知,经历了一个肯定——否定——再次肯定的历程,从整体上呈现出一种螺旋式上升的态势。在1940年代末和1950年代初,徐迟对梭罗和《瓦尔登湖》的态度之所以出现阴阳两重天的巨变,基本上可以归结为是在政治和个人双重因素的制约下,译者对作者和原作本身的体悟有所变动。到了1980年代和1990年代之后,晚年的徐迟对梭罗及其《瓦尔登湖》的欣赏依旧,但更多时候徐迟是在借梭罗和《瓦尔登湖》来巧妙地剖白心迹,进行自我言说。     

致病性大肠杆菌O_(157):H_7基因分型的研究进展

就目前的大肠杆菌O157:H7基因分型方法进行了综述,将其归纳为3类:基于DNA的限制性酶切技术、基于特异靶标的PCR扩增技术、基于基因组特定位点的DNA多态性分析技术,阐述和分析了这些技术所涉及的方法和技术特点。认为,大肠杆菌O157:H7具有重要的公共卫生学意义,开展流行病学调查和病原溯源追踪是防控大肠杆菌病的重要手段,而基因分型是大肠杆菌O157:H7鉴定和示踪的重要技术。     

2009 H1N1 Fatalities: The New Mexico Experience

Abstract: Histopathologic features of New Mexico 2009 H1N1 fatalities have not been representative of those reported nationwide. We retrospectively reviewed medical records of all New Mexico 2009 pandemic influenza A (pH1N1) fatalities (n = 50). In cases in which autopsy was performed (n = 12), histologic sections and culture results were examined. In contrast to previously published studies, the majority of our fatalities did not have diffuse alveolar damage (DAD) (2/12; 16.7%). Common findings included pulmonary interstitial inflammation and edema, tracheobronchitis, and pneumonia. Two cases had significant extra‐pulmonary manifestations: myocarditis and cerebral edema with herniation. The majority had a rapid disease course: range from 1 to 12 days (median, 2 days), and Native Americans were disproportionately represented among fatalities. These findings suggest that New Mexico H1N1 fatalities generally did not survive long enough to develop the classic picture of DAD. Pathologists should be aware that H1N1 may cause extra‐pulmonary pathology and perform postmortem cultures and histologic sampling accordingly.     

道德善、理性化与法的规范性——以哈特理论为中心的反省

法律的规范性是法律理论中最为重要的法律概念之一,并且学者通常以“应当”作为规范性的核心含义。然而,如果进一步追问何谓“应当”,那么就会逐渐引出“可辩护性”的概念。哈特的法律理论之所以是重要的,就因为是他首先意识到可辩护性的重要意义。不过,可辩护性背后隐含着“道德善”的概念,那么这是否意味着法律实证主义主张是错误的？并不必然,要想系统说明应当、可辩护性与道德善这三个概念,就必须借助对于“理性化框架”的整体说明,而法律实证主义在这其中就存在着诸种成立的可能性。     

Being Positive About Positivism

Book reviewed in this article:
Matthew H. Kramer, In Defense of Legal Positivism: Law Without Trimmings     

Let Them Eat Lunch: The Impact of Universal Free Meals on Student Performance

This paper investigates the impact of extending free school lunch to all students, regardless of income, on academic performance in New York City middle schools. Using a difference-in-differences design and unique longitudinal, student-level data, we derive credibly causal estimates of the impacts of “Universal Free Meals” (UFM) on test scores in English Language Arts (ELA) and mathematics, and participation in school lunch. We find UFM increases academic performance by as much as 0.083 standard deviations in math and 0.059 in ELA for non-poor students, with smaller, statistically significant effects of 0.032 and 0.027 standard deviations in math and ELA for poor students. Further, UFM increases participation in school lunch by roughly 11.0 percentage points for non-poor students and 5.4 percentage points for poor students. We then investigate the academic effects of school lunch participation per se, using UFM as an instrumental variable. Results indicate that increases in school lunch participation improve academic performance for both poor and non-poor students; an additional lunch every two weeks increases test scores by roughly 0.08 standard deviations in math and 0.07 standard deviations in ELA. Finally, we explore potential unintended consequences for student weight outcomes, finding no evidence that UFM increases the probability that students are obese or overweight. We also find no evidence of increases in average body mass index (BMI). Instead, we find some evidence that participation in school lunch improves weight outcomes for non-poor students. Results are robust to an array of alternative specifications and assumptions about the sample.