Direct interaction of the U1 snRNP-A protein with the upstream efficiency element of the SV40 late polyadenylation signal

An integral component of the splicing machinery, the U1 snRNP, is here implicated in the efficient polyadenylation of SV40 late mRNAs. This occurs as a result of an interaction between U1 snRNP-A protein and the upstream efficiency element (USE) of the polyadenylation signal. UV cross-linking and immunoprecipitation demonstrate that this interaction can occur while U1 snRNP-A protein is simultaneously bound to U1 RNA as part of the snRNP. The target RNA of the first RRM (RRM1) has been shown previously to be the second stem-loop of U1 RNA. We have found that a target for the second RRM (RRM2) is within the AUUUGURA motifs of the USE of the SV40 late polyadenylation signal. RNA substrates containing the wild-type USE efficiently bind to U1 snRNP-A protein, whereas substrates fail to bind when motifs of the USE were replaced by linker sequences. The addition of an oligoribonucleotide containing a USE motif to an in vitro polyadenylation reaction inhibits polyadenylation of a substrate representing the SV40 late polyadenylation signal, whereas a mutant oligoribonucleotide, a nonspecific oligoribonucleotide, and an oligoribonucleotide containing the U1 RNA-binding site had much reduced or no inhibitory effects. In addition, antibodies to bacterially produced, purified U1 snRNP-A protein specifically inhibit in vitro polyadenylation of the SV40 late substrate. These data suggest that the U1 snRNP-A protein performs an important role in polyadenylation through interaction with the USE. Because this interaction can occur when U1 snRNP-A protein is part of the U1 snRNP, our data provide evidence to support a link between the processes of splicing and polyadenylation, as suggested by the exon definition model.     

Strength failure of spatial reticulated structures under multi-support excitation

Under strong earthquakes, long-span spatial latticed structures may collapse due to dynamic instability or strength failure. The elasto-plastic dynamic behaviors of three spatial latticed structures, including two double-layer cylindrical shells and one spherical shell constructed for the 2008 Olympic Games in Beijing, were quantitatively examined under multi-support excitation (MSE) and uniform support excitation (USE). In the numerical analyses, several important parameters were investigated such as the peak acceleration and displacement responses at key joints, the number and distribution of plastic members, and the deformation of the shell at the moment of collapse. Analysis results reveal the features and the failure mechanism of the spatial latticed structures under MSE and USE. In both scenarios, the double-layer reticulated shell collapses in the "overflow" mode, and the collapse is governed by the number of invalid plastic members rather than the total number of plastic members, beginning with damage to some of the local regions near the supports. By comparing the numbers and distributions of the plastic members under MSE to those under USE, it was observed that the plastic members spread more sufficiently and the internal forces are more uniform under MSE, especially in cases of lower apparent velocities in soils. Due to the effects of pseudo-static displacement, the stresses in the members near the supports under MSE are higher than those under USE.     

Effects of microstructure on inverse fracture occurring during drop-weight tear testing of high-toughness X70 pipeline steels

The effects of microstructure on inverse fracture occurring in the hammer-impacted region were analyzed after conducting a drop-weight tear test (DWTT) on high-toughness pipeline steels. Three kinds of steels were fabricated by varying the alloying elements, and their microstructures were varied by the rolling conditions. The pressed-notch (PN) or chevron-notch (CN) DWTT and Charpy V-notch (CVN) impact tests were conducted on the rolled steel specimens, and the results were discussed in comparison with the data obtained from CVN tests of prestrained specimens. In the hammer-impacted region of the DWTT specimens, abnormal inverse fracture having a cleavage fracture mode appeared, and the inverse fracture area correlated well with the upper-shelf energy (USE) obtained from the CVN test and with the grain size. The steel specimens having a higher USE or having coarse polygonal ferrite tended to have a larger inverse fracture area than those having a lower USE or having fine acicular ferrite. This was because steels having a higher impact absorption energy required higher energy for fracture initiation and propagation during the DWTT. These results were confirmed by the CVN data of prestrained steel specimens.     

Correlation of microstructure and fracture properties of API X70 pipeline steels

Effects of microstructure on fracture toughness and transition temperature of high-toughness X70 pipeline steels were investigated in this study. Three types of steels were fabricated by varying alloying elements such as C, Cu, and Mo, and their microstructures were varied by rolling conditions such as finish rolling temperature and finish cooling temperature. Charpy V-notch (CVN) impact tests and pressed notch drop-weight tear tests (DWTT) were conducted on the rolled steel specimens. The Charpy impact test results indicated that the specimens rolled in the single-phase region of the steel containing a reduced amount of C and Mo had the highest upper shelf energy (USE) and the lowest energy transition temperature (ETT) because of the appropriate formation of acicular, quasipolygonal, or polygonal ferrite and the decreased fraction of martensite-austenite constituents. Most of the specimens rolled in the single-phase region also showed excellent DWTT properties as the percent shear area (pct SA) well exceeded 85 pct, irrespective of finish cooling temperatures, while their USE was higher than that of the specimens rolled in the two-phase region. Thus, overall fracture properties of the specimens rolled in the single-phase region were better than those of the specimens rolled in the two-phase region, considering both USE and pct SA.     

Effects of Microstructure on CVN Impact Toughness in Thermomechanically Processed High Strength Microalloyed Steel

Investigation on the correlation between microstructure and CVN impact toughness is of practical importance for the microstructure design of high strength microalloyed steels. In this work, three steels with characteristic microstructures were produced by cooling path control, i.e., steel A with granular bainite (GB), steel B with polygonal ferrite (PF) and martensite-austenite (M-A) constituent, and steel C with the mixture of bainitic ferrite (BF), acicular ferrite (AF), and M-A constituent. Under the same alloy composition and controlled rolling, similar ductile-to-brittle transition temperatures were obtained for the three steels. Steel A achieved the highest upper shelf energy (USE), while large variation of impact absorbed energy has been observed in the ductile-to-brittle transition region. With apparently large-sized PF and M-A constituent, steel B shows the lowest USE and delamination phenomenon in the ductile-to-brittle transition region. Steel C exhibits an extended upper shelf region, intermediate USE, and the fastest decrease of impact absorbed energy in the ductile-to-brittle transition region. The detailed CVN impact behavior is studied and then linked to the microstructural features.     

AN ANALYSIS-OF-VARIANCE MODEL FOR THE ASSESSMENT OF CONFIGURAL CUE UTILIZATION IN CLINICAL JUDGMENT.

INTRODUCES AN ANALYSIS-OF-VARIANCE TECHNIQUE TO ASSESS CONFIGURAL CUE UTILIZATION IN CLINICAL JUDGMENT. USE OF THE MODEL IS ILLUSTRATED BY AN EXPERIMENT IN WHICH 9 RADIOLOGISTS JUDGED THE MALIGNANCY OF GASTRIC ULCERS ON THE BASIS OF ROENTGENOLOGICAL SYMPTOMS. THE MODEL PROVED CAPABLE OF DESCRIBING LINEAR AND CONFIGURAL CUE USE IN A PRECISE QUANTITATIVE MANNER. ALTHOUGH THERE WERE A SUBSTANTIAL NUMBER OF INSTANCES IN WHICH A JUDGE COMBINED THE SYMPTOMS CONFIGURALLY, MOST OF THE VARIATION IN A JUDGE'S RESPONSES WAS ACCOUNTED FOR BY THE NONCONFIGURAL USE OF INDIVIDUAL SYMPTOMS. IMPLICATIONS OF THE TECHNIQUE FOR THE STUDY OF DIAGNOSTIC EXPERTS ARE DISCUSSED. (27 REF.) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Correlation of microstructure and fracture properties of API X70 pipeline steels

Effects of microstructure on fracture toughness and transition temperature of high-toughness X70 pipeline steels were investigated in this study. Three types of steels were fabricated by varying alloying elements such as C, Cu, and Mo, and their microstructures were varied by rolling conditions such as finish rolling temperature and finish cooling temperature. Charpy V-notch (CVN) impact tests and pressed notch drop-weight tear tests (DWTT) were conducted on the rolled steel specimens. The charpy impact test results indicated that the specimens rolled in the single-phase region of the steel containing a reduced amount of C and Mo had the highest upper shelf energy (USE) and the lowest energy transition temperature (ETT) because of the appropriate formation of acicular, quasipolygonal, or polygonal ferrite and the decreased fraction of martensite-austenite constituents. Most of the specimens rolled in the single-phase region also showed excellent DWTT properties as the percent shear area (pct SA) well exceeded 85 pct, irrespective of finish cooling temperatures, while their USE was higher than that of the specimens rolled in the two-phase region. Thus, overall fracture properties of the specimens rolled in the single-phase region were better than those of the specimens rolled in the two-phase region, considering both USE and pct SA. are jointly appointed with the Materials Science and Engineering Department, Pohang University of Science and Technology.     

ABBREVIATED FORM OF THE WISC FOR USE WITH BRAIN-DAMAGED AND MENTALLY RETARDED CHILDREN.

DISCUSSES THE USE OF AN ABBREVIATED FORM OF THE WISC TO INCLUDE BRAIN-DAMAGED AND MENTALLY RETARDED GROUPS OF CHILDREN. THIS ABBREVIATED FORM MAKES USE OF PART OF THE ITEMS IN EACH SUBTEST, THEREBY NOT ONLY SHORTENING THE TEST BUT ALSO PERMITTING THE TEST TO RETAIN ALL OF ITS SUBTESTS. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

离心萃取机在铼回收中的运行研究

离心萃取机具有效率高、稳定性好、分离速度快、自动化程度高等优势,在生物医药及化工领域应用广泛。介绍了离心萃取机的结构、工作原理和性能,重点对使用离心萃取机新设备替代传统萃取槽回收钼精矿中的铼进行了试验研究和工业化试生产,获得较好的结果,实现了铼和其它元素的有效分离。该设备的运行对其它行业铼回收具有一定的借鉴作用。     

RESEARCH FOR PSYCHOLOGISTS AT THE INTERFACE OF THE SCIENTIST AND HIS INFORMATION SYSTEM.

SUMMARIZES "REPRESENTATIVE FINDINGS ON SCIENTISTS' USE OF INFORMATION . . . (COMMENTS) ON CONCEPTUALIZATION AND THEORY CONCERNING INFORMATION USE . . . (DISCUSSES) 7 METHODOLOGIES THAT PROMISE CONTINUED UTILITY FOR INVESTIGATIONS IN THIS AREA, AND . . . (SUGGESTS) FURTHER RESEARCH THAT PARTICULARLY NEEDS THE ATTENTION OF PSYCHOLOGISTS." (54 REF.) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Does It Matter What You Call It? The Relationship Between Labeling Unwanted Sexual Experiences and Distress.

Using cross-sectional data from 2 samples of women attending a university (N = 1,395), the author examined the relationship among women's labeling of their unwanted sexual experiences (USEs) with dating partners and a variety of psychological and school-related outcomes. Three competing path analysis models were tested to determine whether the distress associated with sexual victimization stems from the USE itself, from the woman's self-definition as a victim, or from both. The best-fitting model indicates that labeling is irrelevant to the determination of negative outcomes and that it is the USE itself that is associated with psychological and school-related distress. These results suggest that labeling cannot be considered a valid criterion for determining who has experienced sexual victimization. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Effects of Ti addition on cleavage fracture in Nb-Cr-Ti solid-solution alloys

The fracture toughness of Nb-Cr-Ti solid-solution alloys has been shown to be greatly improved by Ti addition, but the mechanism of toughness enhancement has not been established. In this study, critical experiments were performed on the tough Nb-Cr-Ti alloy to characterize the crack-tip fracture process and to investigate the origin of fracture toughness. In addition, theoretical calculations of the unstable stacking energy (USE) and the Peierls-Nabarro (P-N) energy and stress were performed as a function of Ti content in the Nb-Cr-Ti alloys. The experimental results indicate that the fracture toughness in the tough Nb-Cr-Ti alloy originates from extensive dislocation emission that suppresses cleavage crack propagation from the crack tip. The theoretical calculation indicates that Ti addition lowers the P-N energy and stress, but has little effect on the USE. These results are used to elucidate the effects of Ti addition on cleavage fracture in Nb-Cr-Ti alloys by considering the influence of the P-N energy and stress values on (1) dislocation mobility, (2) crack-tip dislocation emission, (3) fracture toughness, and (4) brittle-to-ductile fracture transition. It is concluded that dislocation emission in the Nb-Cr-Ti alloys appears to be controlled by the P-N energy, which influences dislocation mobility, rather than by the USE, which influences dislocation nucleation. Ti increases the fracture toughness of Nb-Cr-Ti alloys by increasing dislocation mobility and dislocation emission from the crack tip through a reduction of the P-N energy and stress. An erratum to this article is available at .     

圆筒式离心萃取器在锆铪分离中的应用

应用圆筒式离心萃取器对锆铪进行了分离,锆铪皆达到核反应堆可用的纯度。介绍了圆筒式离心萃取器的操作原理,并与混合澄清槽进行了比较,显示了其快速萃取的优点。     

利用矮型斜底箱式混合澄清器从含铀煤灰酸浸矿浆中萃取铀以及降低有机相损

介绍了新型萃取器－矮型斜底箱式混合澄清器及利用此萃取器从含铀煤灰酸浸矿浆中萃取铀的小型试验与连续台架试验结果及影响溶剂损失的主要因素。试验结果表明,处理１ｔ含铀煤灰,损失胺１５６ｇ;生产１ｋｇ铀,实际损失胺５４ｇ。推测,若使用晚小的三脂肪胺,可能会取得更满意的结果。     

从钨矿苏打浸出液中直接萃取钨的连续运转试验

采用工业实际钨矿苏打浸出液在离心萃取系统中进行了季铵盐直接萃取钨的连续运转试验。结果表明,过程运行稳定;当料液中Mo/WO3在4%左右时,在优化的操作条件下,WO3的萃取率大于97%,反萃液WO3浓度大于160g/L,杂质P、Si的除去率大于97%。长期运转试验表明,有机相在累计运转1000h后萃取-反萃取性能保持不变。试验结果为碱性介质萃取钨新工艺的工业化铺平了道路。     

国内稀土行业中应用的萃取器

介绍了稀土行业中应用的各式萃取器,重点介绍了混合澄清器的结构和原理,并针对稀土分离的特点提出了萃取器的研究方向.     

Study on Transfer and Interfacial Kinetics of Neodymium and Samarium in Membrane Based Extraction

Ｔｈｅｅｘｔｒａｃｔｉｏｎｔｅｃｈｎｏｌｏｇｙｏｆｈｏｌｌｏｗｆｉｂｂｅｒｍｅｍｂｒａｎｅ (ＨＦＭ ) ,ｗｈｉｃｈｗａｓｄｅｖｅｌｏｐｅｄｉｎｅａｒｌｙ 1 980ｓ ,ｉｓａｎｅｗｋｉｎｄｏｆｓｅｐａｒａｔｉｏｎｍｅｔｈｏｄｃｏｍｂｉｎｅｄｐｒｏｃｅｓｓｅｓｏｆｌｉｑｕｉｄ -ｌｉｑｕｉｄａｎｄｍｅｍｂｒａｎｅｅｘｔｒａｃｔｉｏｎ .Ｔｈｉｓｍｅｔｈｏｄｃａｎｏｆ ｆｅｒｓｅｖｅｒａｌａｄｖａｎｔａｇｅｓｃｏｍｐａｒｅｄｗｉｔｈｃｏｎｖｅｎ ｔｉｏｎａｌｅｘｔｒａｃｔｏｒｓ[1～ 2 ] .Ｉｔｃａｎａｌｓｏｐｒｏｖ…