Isomerization in olefin formation in radiation degradation of poly(olefin sulphone)s

Summary Gamma irradiation of poly(3-methyl-1-butene sulphone) in the solid state at 20°C produced a mixture of isomers,viz. 3-methyl-1-butene (61%), 2-methyl-1-butene (2%) and 2-methyl-2-butene (37%). Similarly, poly(1-butene sulphone) yielded 1-butene (65%) and 2-butene (35%). A hydride shift reaction in a polymer cation produced by main-chain scission is proposed to account for the isomerization.     

How do triers of fact infer the accuracy of eyewitness identifications? Using memory for peripheral detail can be misleading.

107 undergraduate eyewitnesses to a staged theft made identifications from a photo spread and then responded to 11 questions that measured their memory for peripheral details. Results indicate that witnesses who accurately identified the thief (n?=?57) averaged fewer correct answers on the peripheral details test than did eyewitnesses who identified an innocent person (n?=?32). The remaining witnesses (n?=?18) made no identification. 94 undergraduates acting as jurors viewed cross-examinations of 47 accurate and 24 inaccurate eyewitnesses and indicated their belief that the witness had or had not properly identified the thief. The cross-examination that scrutinized and documented the witnesses' memory for trivial details lowered Ss' belief of the eyewitnesses' identification accuracy. This discrediting effect was stronger for accurate than for inaccurate eyewitnesses. It is argued that jurors inappropriately assumed a positive correlation between accuracy in identifying the thief and memory for peripheral details. (18 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The use of acoustic emission techniques to monitor fracture processes in high strength precipitation hardened aluminum alloys

The ductile fracture of dispersion hardened aluminum alloy containing brittle intermetallic inclusions is briefly reviewed. The effect of the size, distribution and chemical composition of the inclusions in affecting the matrix fracture behavior is discussed.The potential of acoustic emission techniques in being able to discriminate between different microstructures produced by various thermomechanical treatment is emphasized. It is shown that processes that affect dislocation motion, i.e., cold work, precipitation, solute atom diffusion, etc., also affect the acoustic response, thus making the AE technique extremely useful for the study of flow and fracture behavior of aluminum alloys.     

Chemical vapour deposition of titanium nitride on plasma nitrided steel

Ferritic and austenitic nitriding by the plasma nitriding technique were investigated for the modification of steel substrates prior to the chemical vapour deposition of titanium nitride at 1273 K. It was confirmed that prenitriding enhances the growth of the titanium nitride layer and it was found that a TiN coating can be formed using substrate derived nitrogen only. Control of porosity, arising during austenitic nitriding, was investigated and it was found that in practice this phenomenon could not be avoided.     

Homograft replacement of fungal endocarditic pulmonary valve

Right-sided infective endocarditis is uncommon but is increasingly seen as a reflection of the prevalence of drug abuse, chronic intravenous catheters and associated congenital malformations. Isolated pulmonary valve endocarditis has rarely been reported and there has been only one previous report of isolated pulmonary valve fungal endocarditis. This resolved with antimicrobials. We describe a case of isolated mycotic pulmonary valve endocarditis resistant to existing anti-fungal chemotherapy, which necessitated pulmonary valve resection and replacement with a homograft.     

Review of Behavioral scientists in courts and corrections.

Reviews the book, Behavioral scientists in courts and corrections by James T. Ziegenfuss Jr. (1985). Ziegenfuss has put together a systematic account of the activities of behavioural scientists in courts and corrections in a manner that is both coherent and impressive. The book succeeds in its goal of linking law and behavioural science largely because Ziegenfuss provides powerful examples and numerous case studies that illustrate concretely the applications that are possible in the psychology/law interface. Ziegenfuss had three main objectives for the book: to define the functions of behavioural scientists in courts and corrections, to illustrate how these functions contribute meaningfully to court and correctional organizations, and to provide behavioural scientists with an understanding of their potential contributions. Generally, these three objectives are well met. Nevertheless, there are some omissions that are surprising. Although there are several things that I would like to have seen in this book (e.g., a discussion of the law and economics movement), the most conspicuously absent features are discussions of training and discussions of ethics. In fairness to Ziegenfuss, training and ethical issues were not a part of his explicitly stated purposes in the book. I recommend this book for behavioural scientists who are working or intend to work in the legal system. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Parameters for detection of mutagenesis of 1,2-dimethylhydrazine using an in vitro Bacillus subtilis system

Parameters for detection of mutagenesis of 1,2-dimethylhydrazine (DMH) using a Bacillus subtilis microbial assay are defined. His+ and his met mutations were induced in B. subtilis TKJ6321 in the absence of rat liver S-9 Mix. This B subtilis mutant showed a greater sensitivity to this chemical than did Salmonella typhimurium TA1535. Protein-binding studies with bovine serum albumin showed the capacity for DMH to bind non-specifically to protein. S-9 mix from Aroclor pretreated animals appeared to decrease the mutagenic response. Kinetics of mutagen stability were also shown, thereby demonstrating the need for more complete investigation of known chemical carcinogens which give negative results in the Ames bioassay alone.     

Isolation of a ribozyme with 5'-5' ligase activity

BACKGROUND: Many new ribozymes, including sequence-specific nucleases, ligases and kinases, have been isolated by in vitro selection from large pools of random-sequence RNAs. We are attempting to use in vitro selection to isolate new ribozymes that have, or can be evolved to have, RNA polymerase-like activities. As phosphorimidazolide-activated nucleosides are extensively used to study non-enzymatic RNA replication, we wished to select for a ribozyme that would accelerate the template-directed ligation of 5'-phosphorimidazolide-activated oligonucleotides. RESULTS: Ribozymes selected to perform the desired template-directed ligation reaction instead ligated themselves to the activated substrate oligonucleotide via their 5'-triphosphate, generating a 5'-5' P1,P4-tetraphosphate linkage. Deletion analysis of one of the selected sequences revealed that a 54-nucleotide RNA retained activity; this small ribozyme folds into a pseudoknot secondary structure with an internal binding site for the substrate oligonucleotide. The ribozyme can also synthesize 5'-5' triphosphate and 5'-5' pyrophosphate linkages. CONCLUSIONS: The emergence of ribozymes that accelerate an unexpected 5'-5' ligation reaction from a selection designed to yield template-dependent 3'-5' ligases suggests that it may be much easier for RNA to catalyze the synthesis of 5'-5' linkages than 3'-5' linkages. 5'-5' linkages are found in a variety of contexts in present-day biology. The ribozyme-catalyzed synthesis of such linkages raises the possibility that these 5'-5' linkages originated in the biochemistry of the RNA world.