Dimer interface of glutathione S-transferase from Arabidopsis thaliana: influence of the G-site architecture on the dimer interface and implications for classification

The three-dimensional structure of glutathione S-transferase from Arabidopsis thaliana has been solved at 2.2 A resolution (Reinemer et al., 1996). The enzyme forms a dimer of two identical subunits. The structure shows a new G-site architecture and a novel and unique dimer interface. Each monomer of the protein forms a separate G-site. Therefore, the requirements on the dimer interface are reduced. As a consequence, the interactions between the monomers are weaker and residues at the dimer interface are more variable. Thus, the dimer interface looses its relevance for a classification of plant glutathione S-transferases and the formation of heterodimers becomes even more difficult to predict.     

Evaluating the impact of CASE: an empirical comparison of retrospective and cross-sectional survey approaches

The purpose of this paper is to evaluate two methods of assessing the productivity and quality impact of Computer Aided Software Engineering (CASE) and Fourth Generation Language (4GL) technologies: (1) by the retrospective method; and (2) the cross-sectional method. Both methods involve the use of questionnaire surveys. Developers' perceptions depend on the context in which they are expressed and this includes expectations about the effectiveness of a given software product. Consequently, it is generally not reliable to base inferences about the relative merits of CASE and 4GLs on a cross-sectional comparison of two separate samples of users. The retrospective method that requires each respondent to directly compare different products is shown to be more reliable. However, there may be scope to employ cross-sectional comparisons of the findings from different samples where both sets of respondents use the same reference point for their judgements, and where numerical rather than verbal rating scales are used to measure perceptions.     

Preferential exclusion of sucrose from recombinant interleukin-1 receptor antagonist: role in restricted conformational mobility and compaction of native state

Understanding the mechanism for sucrose-induced protein stabilization is important in many diverse fields, ranging from biochemistry and environmental physiology to pharmaceutical science. Timasheff and Lee [Lee, J. C. & Timasheff, S. N. (1981) J. Biol. Chem. 256, 7193-7201] have established that thermodynamic stabilization of proteins by sucrose is due to preferential exclusion of the sugar from the protein's surface, which increases protein chemical potential. The current study measures the preferential exclusion of 1 M sucrose from a protein drug, recombinant interleukin 1 receptor antagonist (rhIL-1ra). It is proposed that the degree of preferential exclusion and increase in chemical potential are directly proportional to the protein surface area and that, hence, the system will favor the protein state with the smallest surface area. This mechanism explains the observed sucrose-induced restriction of rhIL-1ra conformational fluctuations, which were studied by hydrogen-deuterium exchange and cysteine reactivity measurements. Furthermore, infrared spectroscopy of rhlL-1ra suggested that a more ordered native conformation is induced by sucrose. Electron paramagnetic resonance spectroscopy demonstrated that in the presence of sucrose, spin-labeled cysteine 116 becomes more buried in the protein's interior and that the hydrodynamic diameter of the protein is reduced. The preferential exclusion of sucrose from the protein and the resulting shift in the equilibrium between protein states toward the most compact conformation account for sucrose-induced effects on rhIL-1ra.     

Identification of novel exons 3'' to the human SNRPN gene

This paper examines the relationship between self-efficacy and social power (expert and referent) and how the application of this relationship, leads to client adherence and compliance. Referent power is defined, including methods that health care professionals may use to develop and apply referent power. Expert power is defined and addressed in the context of referent power, self-esteem and self-efficacy as a means of promoting adherence. Self-efficacy as a concept is defined and explored in the context of social power. The relationships between self-efficacy and social power (expert and referent) are shown as important determinants of adherence and compliance. The theory of the application of referent and expert power in relationship with self-efficacy has been compared with an effective programme, yielding high compliance, at Western Psychiatric Institute and Clinic, showing the theory's relevance and applicability in determining compliance. Explored are the reasons for non-compliance in the elderly population and how the theory model can remedy these detriments for compliance. The empowerment of elderly patients through the application of this theory to medication compliance is examined. The determination of adherence and compliance is shown by the application of the relationship between self-efficacy and both expert and referent power.     

One or two incisions for nephroureterectomy in transitional cell renal pelvis tumours

A retrospective study comprising 18 patients with transitional cell renal pelvis tumours (TCPT) was carried out to evaluate the results after two different surgical procedures for nephroureterectomy. The kidney was removed by a flank incision and the lower part of the ureter by either an incision in the lower part of the abdomen or intussusception of the ureter followed by transurethral resection of the ureteral orifice. Eight patients were subjected to nephroureterectomy by means of two incisions and another eight patients underwent a simple nephrectomy followed by ureteral intus-susception and transurethral resection. Two patients received other treatments. After nephroureterectomy with a separate incision for ureterectomy, the average hospital stay was 12 days, compared with 7.5 days in patients operated upon with only one abdominal incision. Recurrence of tumour or survival was not significantly different in the two groups.     

A biased percolation model for the analysis of electronic-device degradation

The biased percolation model is proposed for investigating device degradation and failure associated with the generation of defects due to local Joule heating. The degradation processes of a thin conducting or semiconducting film is monitored by a set of relevant indicators, such as: the evolution of damage pattern, the current distribution, the film resistance and its fluctuations, the defect concentration, the film lifetime, etc. The conductor-insulator (CI) and conductor-superconductor (CS) like degradation processes are considered. The results can be used to propose non-destructive indicators to test the reliability of samples and to interpret the corresponding experiments.     

Presupposition failure — A comedy of errors

Presuppositions of utterances are the pieces of information you convey with an utterance no matter whether your utterance is true or not. We first study presupposition in a very simple framework of updating propositional information, with examples of how presuppositions of complex propositional updates can be calculated. Next we move on to presuppositions and quantification, in the context of a dynamic version of predicate logic, suitably modified to allow for presupposition failure. In both the propositional and the quantificational case, presupposition failure can be viewed as error abortion of procedures. Thus, a dynamic assertion logic which describes the preconditions for error abortion is the suitable tool for analysing presupposition.     

Error in the UNITY substitution rule for subscripted operators

UNITY, introduced by Chandy and Misra [ChM88], is a programming logic intended to reason about temporal properties of distributed programs. Despite the fact that UNITY does not have the full power of, for example, linear temporal logic, it enjoys popularity due to its simplicity.There was however a serious problem with the Substitution Rule. The logic is incomplete without the rule, and with the rule it is inconsistent.