The Effect of Surface Stresses on the Critical Debonding Stress Around Nanoparticles

With the aid of an energy analysis and the surface elasticity theory, this work provides a closed form solution for the critical debonding stress of a rigid nanoparticle embedded in an elastic matrix subjected to a remote hydrostatic stress. It is proved that the debonding stress depends on the particle radius, the matrix elastic properties and the fracture energy per unit surface. The solution allows quantifying the effects of surface elastic constants, also showing that the smaller the particle size the more significant those effects are.     

A decentralized kinematic control architecture for collaborative and cooperative multi-arm systems

In this paper a two-layer decentralized framework for kinematic control of cooperative and collaborative multi-robot systems is developed. The motion of the system is specified at the workpiece level, by adopting a task-oriented formulation for cooperative tasks. The first layer computes the motion of the single arms in the system. In detail, the control unit of each robot computes the end-effector motion references in a decentralized fashion on the basis of the knowledge of the assigned cooperative task and the motion references computed by its neighbors. Then, in the second layer, each control unit computes the reference joint motion of the corresponding manipulator from the end-effector reference motion. The approach is, then, tested in simulation on a work-cell composed by several manipulators, and experimentally on a dual-arm kinematically redundant work-cell composed by industrial manipulators.     

Essentialism revisited: Evolutionary theory and the concept of mental disorder.

J. C. Wakefield's (1999) elaboration of his harmful dysfunction analysis (HDA) of mental disorder does little to address previous criticisms (S. O. Lilienfeld & L. Marino, 1995) and instead reveals further conceptual weaknesses in his position. The authors demonstrate that (a) a Roschian analysis can account for the results of all of Wakefield's conceptual experiments and predicts a number of judgments of disorder not predicted by the HDA, (b) the HDA is incapable in many cases of providing a scientifically nonarbitrary distinction between disorder and nondisorder, and (c) the HDA cannot account for failures of cultural exaptations, mismatches between evolutionary design and novel environments, or defenses against threat. The authors argue that the HDA has been convincingly falsified and discuss the failure of essentialistic concepts to resolve controversies in other domains of biological science. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

On fault-tolerant observers

The problem of designing asymptotic observers for multioutput systems with one unreliable output measurement is addressed. It is shown that observers designed on the basis of observability indexes are not fault tolerant, and an observer for linear systems which tolerates failures in one a priori known output is given. The results are extended to nonlinear systems with no inputs: it is pointed out that the proposed design procedure may enlarge the class of nonlinear systems for which a nonlinear observer can be obtained     

On the largest feedback linearizable subsystem

A feedback invariant set of integers is associated with any nonlinear multivariable system which is linear with respect to the inputs: it is shown to be the set of controllability indices of the largest feedback linearizable subsystem, i.e. the largest subsystem which can be made locally linear and controllable by means of nonsingular feedback transformations.     

Efficacy of gene testing for von Hippel-Lindau disease

OBJECTIVE: To determine the efficacy of genetic testing of individuals presenting with features possibly indicative of von Hippel-Lindau (VHL) disease, regardless of other relevant family and clinical details. SETTING AND PARTICIPANTS: Between September 1994 and December 1997, 16 unrelated individuals were referred to Genetic Services of Western Australia by local clinicians and by similar genetic services in other States, for VHL gene mutation analysis because of clinical manifestations suggestive of the diagnosis. METHODS: The subjects were investigated by screening for mutations in the polymerase chain reaction products of the three VHL gene exons using single-stranded conformational polymorphism analysis (SSCP). If no mutations were detected the exons were sequenced, and if no variations were found DNA was examined by Southern analysis for germinal rearrangements. RESULTS: Mutations in the VHL gene were detected in eight of 16 individuals (50%), including 3 individuals with no family history suggestive of VHL disease. Five mutations were detected by SSCP, two by gene sequencing and one by Southern analysis. Each mutation occurred only in a single family and three had not been previously reported. CONCLUSION: Genetic screening of individuals presenting with clinical features suggestive of VHL facilitates confirmation of the diagnosis, accurate genetic counselling and surveillance of at-risk family members. The necessity for costly and time-consuming screening programs can be reduced and screening directed at those carrying the mutation. Our low stringency criteria are justified for screening for VHL mutations.     

Peripheral benzodiazepine receptor expression on leukocytes and neutrophil function during anticonvulsant monotherapy

AIM: To gain a full understanding of the concept of equity and means of promoting and monitoring a more equitable healthservice. BACKGROUND: With previous policy decisions having sidelined equity, a new government is likely to wish to reverse this trend. ORIGINS OF INFORMATION: Government and expert opinion. DATA ANALYSIS: A critical approach to previous literature. KEY ISSUES: Equity is not a unitary concept and so it is explored and dissected using the framework of: Distribution of Resources, Access and Uptake of Healthcare, Standards and Outcomes of Healthcare, Health Status. Means of improving and monitoring equity in these four areas are suggested. CONCLUSIONS: There are a number of ways of considering the concept of equity and for any fruitful discussion to occur there needs to be an agreed working definition. Specific topics are discussed where equity is lacking and a plan of action is suggested which is likely to improve equity in the areas identified.     

The significance of colour velocity and spectral Doppler ultrasound in the differentiation of liver tumours

BACKGROUND: The distinction between malignant mesothelioma (MM) and adenocarcinoma (ACA) in cytologic specimens frequently is difficult, often requiring immunocytochemistry to support the diagnosis. Recent reports have proposed the utilization of antibodies to mesothelial cell clone HBME-1 and thrombomodulin (TM), because they are immunoreactive in MM and less commonly reactive in ACA. Immunoreactivity for the monoclonal antibody CA 19-9 has been observed in many ACAs and reportedly is absent in MM. METHODS: In this study, immunostaining was performed on formalin fixed, paraffin embedded cell blocks from effusions or fine-needle aspirations using the avidin-biotin-peroxidase method. Thirty-eight MMs and 49 ACAs were tested using antibodies to CA 19-9, HBME-1, and TM. RESULTS: Anti-CA 19-9 stained only 1 of the 37 cases of MM tested (3%), but stained 24 of the 49 cases of ACA (49%). Anti-HBME-1 stained 34 of 38 cases of MM (89%), and 28 of 43 cases of ACA tested (65%). Anti-TM stained 24 of 36 cases of MM (67%), and 21 of 40 cases of ACA tested (53%). CONCLUSIONS: CA 19-9 has utility as part of an immunocytochemical panel for distinguishing ACA from MM, because a positive staining reaction would make the diagnosis of MM unlikely. Although HBME-1 and TM can identify MM positively, each frequently is detected in ACA, thus limiting the utility of these antibodies in cytologic specimens.     

Experimental pyeloureterectomy and calyceal neck transection with autotransplantation and bladder advancement

OBJECTIVE: To determine whether Dexon mesh, closely applied to the kidney, provides purchase for sutures to permit bladder/parenchymal apposition on autotransplantation and that, if this line of apposition were some distance from but surrounding renal papillae, urothelium would proliferate to cover exposed parenchyma to form a widely patent lumen; this should facilitate removal of the whole of an upper tract collecting system, retaining renal parenchyma alone. MATERIALS AND METHODS: To test this possibility and explore the practicability of the concept, nine dogs underwent bilateral nephrectomy followed by unilateral autotransplantation: the other kidney was discarded. Because the canine renal pelvis is intrarenal, the ureter was stretched maximally before passing fine scissors into the renal hilum to transect the collecting system as close to the kidney as possible in six of the nine dogs. In the remaining three dogs, partial nephrectomy was performed with division of the calyceal necks under vision. Thinned bladder wall was sutured to Dexon mesh some distance from the collecting tubules; omentum was applied to the suture line. RESULTS: Three dogs were killed prematurely at < 2 weeks because of perioperative complications. Four were killed at 2, 4, 5 and 8 weeks and two at 12 months. Dexon mesh proved to be an effective anchoring fabric, providing close apposition of bladder wall and parenchyma. There was no adhesion of the kidney to peritoneal contents. Urothelial proliferation to cover exposed parenchyma occurred early and by 12 months, a thin stroma was interposed between parenchyma and epithelium. The kidney was preserved in all but one removed electively, this dog having both cystitis and pyelonephritis at 12 months. CONCLUSIONS: This study showed that autotransplantation of a kidney after removal of its collecting system and advancement of thinned bladder wall to renal parenchyma is practicable, with regenerated urothelium bridging the deficiency by covering exposed parenchyma, to create a widely patent lumen.     

Manson's schistosomiasis presenting as a brain tumor. Case report

Neurological complications arising from schistosomiasis are uncommon, and reports of Manson's schistosomiasis presenting as an intracerebral mass lesion are particularly rare. The authors describe the case of a 26-year-old man with a 3-month history of headaches and visual abnormalities. He had immigrated to Canada from Brazil 4 years previously. The patient's general physical and neurological examinations were unremarkable. Magnetic resonance (MR) imaging revealed an enhancing lesion with surrounding edema and mild mass effect in the right occipital lobe. A stereotactic brain biopsy demonstrated intraparenchymal granulomas surrounding Schistosoma masoni eggs. The patient's symptoms resolved following treatment with praziquantel and steroid medications; follow-up MR imaging yielded normal findings. This case demonstrates that neuroschistosomiasis should be considered when an individual presenting with an intracerebral mass has lived in a region in which this disease is endemic.