Analysis of local strain in aluminium interconnects by energy filtered CBED

Energy filtered convergent beam electron diffraction (CBED) was used to investigate localised strain in aluminium interconnects. The quantitative analysis of the experimental patterns is based on a multi-step evaluation procedure which is the main subject of the present paper. The improvements which were made to the analysis method aim at increasing both the automation and the accuracy. The detection of the higher order Laue zone (HOLZ) line positions is performed by means of the Hough transform. The required sub-pixel resolution can be achieved routinely and the achievable accuracy is only limited by the line width and the amount of noise in the patterns. The determination of the strain state is performed via a refinement algorithm which is based on varying the strain state in the sample coordinate system and simulating the patterns for the individual grains until a best fit with the experiment is obtained. For the simulation we have developed a new correction scheme in which the dynamical effects are treated separately for each individual HOLZ line. The results show that the main source of the observed strains is the difference in thermal expansion coefficients. The strain is substantially reduced underneath a hillock in the interconnect. Asymmetries in the strain distribution around the hillock show that the unidirectional diffusion during electromigration tests causes peak strains in areas next to the hillock which may be possible failure sites.     

The role of prostaglandins in the natriuresis of acutely salt-loaded rats

Mechanisms determining the natriuresis in ECV expansion are not yet completely known. The present study was therefore performed to investigate (1) the extent to which prostaglandins (PG) are involved in the natriuresis of ECV expansion and (2) by which mechanisms PG may affect renal Na absorption. In nonexpanded rats the prostaglandin synthetase inhibitor indomethacin (INDO) had no effect on renal function. In 16 Sprague-Dawley rats EVC expansion with isotonic saline corresponding to an increase in body weight of 10% was induced and maintained for 60 min. Ten animals received an oral dose of 10 mg/kg BW of INDO prior to ECV expansion. Six animals served as controls (C). Blood pressure (INDO: 132 +/- 4 (SE); C: 130 +/- 3 mm Hg), GFR (INDO: 12.5 +/- 1.0; C: 10.5 +/- 0.9 ml/min/kg BW), fractional K excretion (INDO: 32.1 +/- 2.6; C: 43.4 +/- 4.8%), CH2O and Na-k-ATPase activities in renal cortex, medulla and papilla did not significantly differ in either group. Significant differences were observed in urinary flow rate (INDO: 0.82 +/- 0.8; C: 1.82 +/- 0.23 ml/min/kg KG) and fractional Na absorption (INDO: 91.9 +/- 1.1; C: 81.7 +/- 1.2%). The results indicate that PG are involved in the natriuresis following acute expansion of the ECV and suggest that PG may inhibit the intrinsic tubular capacity for Na absorption in the rat.     

Excitotoxic spinal cord injury: behavioral and morphological characteristics of a central pain model

The involvement of tyrosine protein phosphorylation in the regulation of endothelial cell (EC) contraction and barrier function is poorly understood. We have previously shown that myosin light chain (MLC) phosphorylation catalyzed by a novel 214 kDa EC myosin light chain kinase (MLCK) isoform is a key event in EC contraction and barrier dysfunction [Garcia et al. (1995): J Cell Physiol 163:510-522; Garcia et al. (1997): Am J Respir Cell Mol Biol 16:487-491]. In this study, we tested the hypothesis that tyrosine phosphatases participate in the regulation of EC contraction and barrier function via modulation of MLCK activity. The tyrosine phosphatase inhibitor, sodium orthovanadate (vanadate), significantly decreased electrical resistance across bovine EC monolayers and increased albumin permeability consistent with EC barrier impairment. Vanadate significantly increased EC MLC phosphorylation in a time-dependent manner (maximal increase observed at 10 min) and augmented both the MLC phosphorylation and permeability responses produced by thrombin, an agonist which rapidly increases tyrosine kinase activities. The vanadate-mediated increase in MLC phosphorylation was not associated with alterations in either phosphorylase A Ser/Thr phosphatase activities or in cytosolic [Ca2+] but was strongly associated with significant increases in EC MLCK phosphotyrosine content. These data suggest that tyrosine phosphatase activities may participate in EC contractile and barrier responses via the regulation of the tyrosine phosphorylation status of EC MLCK.     

Dissipative states in a current-carrying superconducting film

The system of the generalized time-dependent Ginzburg-Landau equations (GTDGLE) describing dirty superconductors nearT _c is solved numerically for a thin quasi-two-dimensional, current-carrying layer. In a certain current range one has superconducting states with dissipation which should lead to a step structure in the current voltage characteristic as observed in experiments.¹ Depending on the parameters one either has phase slip line (PSL) solutions, which are the two-dimensional analogs of the one-dimensional phase slips (PSCs) or vortex street (VS) solutions, where vortices which are nucleated spontaneously in pairs move perpendicular to the direction of the current. We discuss the range of stable existence of these states and transitions between different states.Dedicated to L. Tewordt on the occasion of his 65th birthday.     

The expression of Huntingtin-associated protein (HAP1) mRNA in developing, adult and ageing rat CNS: implications for Huntington's disease neuropathology

Using radioactive in situ hybridization, we have mapped the expression of Huntingtin-associated protein (HAP1) mRNA in rat brain at developmental stages (E12-E19, PO-P21), in adult rats (3 months) and in 'aged' (19-21 months) rats. Using two pairs of 45mer oligonucleotide probes specific for HAP1A and a probe which recognizes regions of both the HAP1A and HAP1B mRNA sequences (panHAP1), we find that the expression of HAP1 mRNA is specific to the CNS and restricted predominantly to anatomically connected limbic structures, particularly the amygdala (medial and corticomedial nuclei), the hypothalamus (arcuate, preoptic, paraventricular and lateral hypothalamic area), bed nucleus of the stria terminalis (BNST) and the lateral septal nuclei. HAP1 mRNA was detected in embryos at E12 and displayed a prevalent distribution in the developing limbic structures by E15. In aged, 19-21-months-old, rats there is a downregulation of HAP1 mRNA expression across all CNS loci where HAP1 was previously abundant. The lowest levels of HAP1 mRNA expression corresponded with the areas of greatest pathological cell loss in Huntington's disease (HD); the caudate putamen, globus pallidus and neocortex. These observations support the suggestion that HAP1 plays an important role in the neuropathology of HD.     

Stepwise transformation of a cholera toxin and a p24 (HIV-1) epitope into D-peptide analogs

BACKGROUND: The evidence suggests that personality traits are hierarchically organized with more specific or lower-order traits combining to form more generalized higher-order traits. Agreement exists across studies regarding the lower-order traits that delineate personality disorder but not the higher-order traits. This study seeks to identify the higher-order structure of personality disorder by examining the phenotypic and genetic structures underlying lower-order traits. METHODS: Eighteen lower-order traits were assessed using the Dimensional Assessment of Personality Disorder-Basic Questionnaire in samples of 656 personality disordered patients, 939 general population subjects, and a volunteer sample of 686 twin pairs. RESULTS: Principal components analysis yielded 4 components, labeled Emotional Dysregulation, Dissocial Behavior, Inhibitedness, and Compulsivity, that were similar across the 3 samples. Multivariate genetic analyses also yielded 4 genetic and environmental factors that were remarkably similar to the phenotypic factors. Analysis of the residual heritability of the lower-order traits when the effects of the higher-order factors were removed revealed a substantial residual heritable component for 12 of the 18 traits. CONCLUSIONS: The results support the following conclusions. First, the stable structure of traits across clinical and nonclinical samples is consistent with dimensional representations of personality disorders. Second, the higher-order traits of personality disorder strongly resemble dimensions of normal personality. This implies that a dimensional classification should be compatible with normative personality. Third, the residual heritability of the lower-order traits suggests that the personality phenotypes are based on a large number of specific genetic components.