Characterization and sequence of the Escherichia coli panBCD gene cluster

A 4589 bp DNA segment containing the Escherichia coli panBCD gene cluster was sequenced, and found to contain 6 complete open reading frames. panB, panC, and panD were identified by subcloning and insertional mutagenesis. The orientation of panD was also confirmed by orientation-specific expression of asparate-1-decarboxylase. panB and panC lie adjacent to one another, but are separated from panD by orf3, which is oriented in the opposite direction. Interruptions in the remaining open reading frames did not affect growth on glucose-minimal medium. No significant similarity to sequences in databases was found for orf1 and orf2. Orf3 contained extensive similarity to reading frames defined by E. coli yjiP, yjiQ, yhgA, and yafD. The function of these amino acid sequences is as yet undefined.     

The short of it: Abbreviating the temporal discounting procedure.

A typical temporal discounting procedure determines the present, subjective value (indifference point) of a delayed outcome at 5 to 8 different delays to that outcome. These indifference points are used to determine a single index of discounting called a discounting rate. One concern that remains in the collection of this data is the high number of trials or choices, resulting in participant fatigue or other factors that may affect the validity of the data. In this report, we propose an abbreviated alternative to the more comprehensive and time-consuming discounting procedure. Specifically, we propose that fewer indifference points can be used to determine statistically equivalent discount rates with no loss in data sensitivity. We reanalyzed temporal discounting data obtained with 7 indifference points, and estimated discount rates from all combinations of 2, 3, and 4 of the 7 indifference points. Results indicate that valid and sensitive discounting indices can be obtained with fewer indifference points, and the most appropriate sets of indifference points are highlighted. The proposed abbreviated procedure is likely to be particularly useful when time constraints or participant fatigue is a concern as well as in repeated-measures contexts. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Response of dermal fibroblast cultures from patients with unusually severe responses to radiotherapy and from ataxia telangiectasia heterozygotes to fractionated radiation

We examined the cytotoxic effects of radiation delivered in daily fractions at clinically relevant doses in plateau phase cultures of skin fibroblast cell strains derived from ataxia telangiectasia (AT) heterozygotes, patients with unusually sensitive responses to radiotherapy, apparently normal patients, and cell bank controls. A gradual linear reduction in surviving fraction versus total dose was observed in the control group, comprised of apparently normal individuals and one patient with a normal clinical response to radiotherapy, after exposure to daily fractions of 2.0 Gy. There was a much steeper decline in surviving fraction among the AT heterozygotes and the group with sensitive responses to radiotherapy, such that after six daily fractions of 2.0 Gy (12 Gy total dose), the mean surviving fraction of the control group was significantly different from that of the AT heterozygotes (P = 0.0009) and that of the patients with unusually sensitive responses to radiotherapy (P = 0.0002). We propose that this assay may be a useful means of identifying cell strains from AT heterozygotes. Based on these results, the hypothesis is discussed that patients who suffer unusually sensitive clinical reactions to radiotherapy may be AT heterozygotes.     

低终轧温度对St15深冲性能的影响及采取的1+3”工艺

分析了低终轧温度对冷轧冲压钢板（St15）成品深冲性能的影响。提出了采和“1＋3”粗轧工艺,经理论计算和现场试验,解决了冷轧深冲钢板在热轧时终轧温度偏低的问题。试验结果表明：粗轧出口温度提高80℃左右,终轧温度提高37℃左右,并且精轧机的电机、主传动能力能够适应1＋3方式轧制。     

船用热轧钢板焊接性能研究

建立了热轧钢板焊接热影响区（HAZ）的连续冷却转变曲线（焊接CCT曲线）,以研究船用热轧钢板的焊接性能。根据所建立的焊接CCT曲线,选择了合理的焊接工艺对10mm厚的船用热轧钢板进行了手工电弧焊,并对焊后的焊接接头进行了宏观检验和X射线探伤、力学性能试验及冲击试验。借助金相显微镜和扫描电镜分析了CCT图中不同冷速条件下的显微组织和焊接接头的显微组织以及冲击断口形貌。试验结果表明：根据建立的焊接CCT曲线,所选择的手工电弧焊的焊接工艺是合理的,焊缝质量良好,焊接接头具有良好的综合性能。     

攀钢纯净钢生产实践与探讨

介绍了攀钢纯净钢生产工艺和试验结果,对纯净钢生产的脱磷、脱硫以及氧氢氮的去除工艺进行了分析,建立了以半钢炼钢技术为代表的攀钢纯净钢生产工艺。     

攀钢连铸高效化技术

介绍了高效连铸以及相关技术在攀钢的应用及效果。通过对钢包精炼的改进和中间包冶金技术的优化,提高了钢水洁净度;结合复合辊、低过热度浇注技术的采用和二冷技术与高速连铸保护渣的研制等新技术、新工艺的研究与应用,全面改善了高拉速条件下的铸坯质量,使攀钢板坯连铸机的铸坯产量、质量以及铸机作业率均有较大的提高。