紫外诱变酿酒酵母筛选耐高温菌株     

李艾  李云凯  程磊 《唐山学院学报》2013,26(3):35-37

以实验室保存的酿酒酵母为初始菌株,采用紫外分光光度法测定菌株浓度,绘制出菌株生长曲线,由此确定出最佳诱变菌龄为3～10h,在此期间利用紫外线对菌株进行诱变,筛选出一株适于在高温下发酵的菌株,紫外线诱变条件为：紫外灯功率10w,照射距离30cm,照射时间3min。此菌株在37℃下培养72h,其成熟发酵醪酒精产率为3．837％。  相似文献   

High-resolution mapping of brain vasculature and its impairment in the hippocampus of Alzheimer's disease mice     

Xiaochuan Zhang  Xianzhen Yin  Jingjing Zhang  Anan Li  Hui Gong  Qingming Luo  Haiyan Zhang  Zhaobing Gao  Hualiang Jiang 《国家科学评论(英文版)》2019,6(6):1223

Accumulating evidence indicates the critical importance of cerebrovascular dysfunction in the pathogenesis of Alzheimer''s disease (AD). However, systematic comparative studies on the precise brain vasculature of wild-type and AD model mice are still rare. Using an image-optimization method for analysing Micro-Optical Sectioning Tomography (MOST) data, we generated cross-scale whole-brain 3D atlases that cover the entire vascular system from large vessels down to smallest capillaries at submicron resolution, for both wild-type mice and a transgenic (APP/PS1) mouse model of AD. In addition to distinct vascular patterns in different brain regions, we found that the main vessels of the molecular layer of the hippocampal dentate gyrus (DG-ml) undergo abrupt changes in both diameter and branch angle, spreading a unique comb-like pattern of capillaries. By using a quantitative analysis workflow, we identified in the hippocampus of AD mice an overall reduction of the mean vascular diameter, volume fraction and branch angle, with most significant impairment in the DG-ml. In addition, virtual endoscopy revealed irregular morphological features in the vessel lumen of the AD mice, potentially contributing to the impairment of blood flow. Our results demonstrate the capability of high-resolution cross-scale evaluation of brain vasculature and underscore the importance of studying hippocampal microcirculation for understanding AD pathogenesis.  相似文献   

提高小学数学学困生成绩点滴谈     

魏敦姬 《教育教学论坛》2020,(3):315-316

通过“心与心的交流和方法与方式的优化”两个方面来阐述如何轻松、愉快、有效、合理地提高小学数学学困生的教学质量。  相似文献   

宽容结构的三个层次     

宋新军 《南通师范学院学报》2008,(4):12-15

谅解、宽容、和谐,是整个宽容结构的三个层次,其中有一个逻辑递进关系。谅解,是实现稳定社会的前提;宽容,是实现稳定社会的环境;和谐,是实现稳定社会的最高境界。这三个层次决定了宽容的可能性与必然性;同时,个人与个人、个人与他人、个人与社会之间的既独立又联系的辩证关系,决定着宽容而和谐的社会环境．以及对个人价值实现的重要作用。  相似文献   

流动注射化学发光葡萄糖生物传感器     

彭友元 《泉州师范学院学报》2001,19(4):32-35

本文提出了一种将酶及所有试剂均加以固定的新型葡萄糖生物传感器 .利用酶促反应产生H2 O2 ,与Luminol-K3 Fe(CN) 6 -H2 O2 化学发光反应相偶合 ,从而可以进行葡萄糖的测定 .线性范围为 5× 10 - 7—— 5× 10 - 4M ,检出限为 2× 10 - 7M ,相对标准偏差RSD为 3.6% (c =4× 10 - 6 M ,n =7) ,单次测定可在 1分钟内完成 .该传感器具有简单、快速 ,灵敏度高等特点 ,已成功应用于血清中葡萄糖的测定 .  相似文献   

In these uncertain times: Educators build cultural awareness through planned international experiences   总被引：1，自引：0，他引：1  

John Kambutu  Lydiah W. Nganga 《Teaching and Teacher Education》2008

This narrative inquiry explored the effectiveness of planned international experiences in promoting cultural awareness, understanding and appreciation among American educators. Participating educators (n=12) were immersed in foreign cultures for 2–3 weeks during three different summers. To document the effectiveness of cultural immersion, participants completed pre- and post-visit surveys. Pre-visit data showed lack of cultural awareness. After the visit, however, participants had gained broader awareness, understanding and appreciation of host cultures such that familiar cultural practices were rarely used as the only point of reference. Follow-up interviews showed possible sustained acculturation.  相似文献   

Genuine Religious Tolerance: Is It a Thing of the Past in Public Schools?     

Paul A. Wagner  Lillian Benavente-McEnery 《Interchange》2008,39(3):327-350

The so-called Culture Wars have made the issue of religious tolerance in schools more confusing than ever. Where once free speech trumped nearly every concern in these wars in the public schools, there is now great concern about whether messages put out are politically correct. The preoccupation teachers now have with avoiding speech or themes likely to get them into trouble has led to a new form of censorship. The authors explain that free speech in the educational forum requires respect for every earnest attempt to get at a legitimate truth claim. In matters religious, this epistemic openness is no longer respected. The argument below does not encourage teachers to engage in debate among students in matters religious, or even to encourage it. Nor are the arguments below aimed at introducing religious discourse as a means of developing skills of critical thinking as the feminist, moral philosopher Nel Noddings has previously recommended. The argument simply concludes with the modest recommendation that teachers be more conscientious about indirectly censoring or trivializing student religious speculations.  相似文献   

Improving network service performance and reliability via links trunking technologies     

GUO Hui WANG Yun-peng WANG Zhi-guang ZHOU Jing-li 《浙江大学学报(A卷英文版)》2006,7(6):1001-1007

INTRODUCTION Because of the critical role that computing sys-tems and networks play in today’s business envi-ronment, it is not surprising that business success often goes to the company with the best information and the most efficient process for delivering that in-formation. As the principal tool for business col-laboration, corporate LANs are a vital resource in enabling today’s enterprises to adopt competitive strategies. The number of users wanting to share and access data across…  相似文献   

Mathematical model of cylindrical form tolerance     

蔡敏  杨将新  吴昭同 《浙江大学学报(A卷英文版)》2004,5(7):890-895

Tolerance is essential for integration of CAD and CAM.Unfortunately,the meaning of tolerances in the national standard is expressed in graphical and language forms and is not adaptable for expression,processing and data transferring with computers.How to interpret its semantics is becoming a focus of relevant studies.This work based on the mathematical definition of form tolerance in ANSI Y 14.5.1 M-1994,established the mathematical model of form tolerance for cylindrical feature.First,each tolerance in the national standard was established by vector equation.Then on the foundation of tolerance's mathematical definition theory,each tolerance zone's mathematical model was established by inequality based on degrees of feature.At last the variance area of each tolerance zone is derived.This model can interpret the semantics of form tolerance exactly and completely.  相似文献   

Comparison of two test methods for VIS: paper-pencil test and CAT*     

Selma Şenel  Ömer Kutlu 《欧洲特需教育杂志》2018,33(5):631-645

This paper examines listening comprehension skills of visually impaired students (VIS) using computerised adaptive testing (CAT) and reader-assisted paper-pencil testing (raPPT) and student views about them. Explanatory mixed method design was used in this study. Sample is comprised of 51 VIS, in 7th and 8th grades. 9 of these students were interviewed for determining student views about tests. Results indicated that scores obtained from CAT are significantly lower than scores obtained from raPPT. Additionally, a positive and high correlation was found between scores of CAT and raPPT. This result suggests that similar ability estimations were made by CAT and raPPT. Another finding is CAT made more reliable predictions, and was completed in shorter duration using fewer items. In qualitative part, student views were gathered through interviews and content analysis revealed three themes as technical features, test features, and psychological effects. In general, students reported positive views about CAT. VIS prefer CAT due to its listening/control options, shorter test durations, clarity of reading, and fairness of test, elimination of dependency to reader. Study provides implications for test developers and test-users to consider CAT as a multi-accommodation for VIS through its advantages.  相似文献