A Fault-Tolerant Software Architecture for Component-Based Systems

Component-based software built from reusable software components is being used in a wide range of applications that have high dependability requirements. In order to achieve the required levels of dependability, it is necessary to incorporate into these complex systems means for coping with software faults. However, the problem is exacerbated if we consider the current trend of integrating off-the-shelf software components, from independent sources, which allow neither code inspection nor changes. To leverage the dependability properties of these systems, we need solutions at the architectural level that are able to guide the structuring of unreliable components into a fault-tolerant architecture. In this paper, we present an approach for structuring fault-tolerant component-based systems based on the C2 architectural style

A new methodology for the improvement of diagnostic immunohistochemistry in canine veterinary pathology: automated system using human monoclonal and polyclonal antibodies Uma nova metodologia para melhora do diagnóstico imunoistoquímico em patologia veterinária canina: sistema automático usando anticorpos humanos monoclonais e policlonais

The authors describe their experience with an automated immunohistochemical system applied to canine tissue samples. Twenty human cellular markers specific monoclonal and polyclonal antibodies and two different antigen retrieval methods were used in normal and neoplastic breast tissue, as well as skin samples obtained from female dogs of pure and mixed breeds. The antibodies tested were the most frequently used in human and veterinary medicine studies, employed with diagnostic purposes in breast pathology, as well as in cancer research. Most of them may be used to study other normal and abnormal tissues and included cytokeratins, progesterone receptor, c-erbB2, p53, MIB-1, PCNA, EMA, vimentin, desmin, alpha-actin, S-100, pan-cadherin, and E-cadherin. The results demonstrated that using an automated staining system it is possible to use different human markers in veterinary pathology. The advantages of automated immunohistochemistry are improved quality, reproducibility, speed, and standardisation.<br>Os autores descrevem sua experiência com um sistema automático de imunoistoquímica aplicada à amostras de tecido canino. Foram utilizados 20 anticorpos humanos monoclonais e policlonais e dois diferentes métodos de recuperação antigênica em tecido mamário normal e neoplásico, bem como em amostras de pele obtidas de cadelas. Os anticorpos testados estão entre os mais usados em estudos de medicina humana e veterinária, com finalidade de diagnóstico em patologia mamária, bem como na pesquisa do câncer. Muitos deles podem ser usados para estudar outros tecidos normais e com alterações e incluem citoqueratinas, receptor de progesterona, c-erbB2, p53, MIB-1, PCNA, EMA, vimentina, desmina, alfa-actina, S-100, pan-caderina e E-caderina. Os resultados demonstraram que usando um sistema automático de imunoistoquímica é possível usar diferentes marcadores humanos em patologia veterinária. As vantagens da imunoistoquímica automatizada são melhora da qualidade, reprodutibilidade, rapidez e padronização

Therapeutic efficacy and toxicity of ²²⁵Ac-labelled vs. ²¹³Bi-labelled tumour-homing peptides in a preclinical mouse model of peritoneal carcinomatosis.

PURPOSE: Targeted delivery of alpha-particle-emitting radionuclides is a promising novel option in cancer therapy. We generated stable conjugates of the vascular tumour-homing peptide F3 both with (225)Ac and (213)Bi that specifically bind to nucleolin on the surface of proliferating tumour cells. The aim of our study was to determine the therapeutic efficacy of (225)Ac-DOTA-F3 in comparison with that of (213)Bi-DTPA-F3. METHODS: ID(50) values of (213)Bi-DTPA-F3 and (225)Ac-DOTA-F3 were determined via clonogenic assays. The therapeutic efficacy of both constructs was assayed by repeated treatment of mice bearing intraperitoneal MDA-MB-435 xenograft tumours. Therapy was monitored by bioluminescence imaging. Nephrotoxic effects were analysed by histology. RESULTS: ID(50) values of (213)Bi-DTPA-F3 and (225)Ac-DOTA-F3 were 53&nbsp;kBq/ml and 67&nbsp;Bq/ml, respectively. The median survival of control mice treated with phosphate-buffered saline was 60&nbsp;days after intraperitoneal inoculation of 1&thinsp;&times;&thinsp;10(7) MDA-MB-435 cells. Therapy with 6&thinsp;&times;&thinsp;1.85&nbsp;kBq of (225)Ac-DOTA-F3 or 6&thinsp;&times;&thinsp;1.85&nbsp;MBq of (213)Bi-DTPA-F3 prolonged median survival to 95&nbsp;days and 97&nbsp;days, respectively. While F3 labelled with short-lived (213)Bi (t (1/2) 46&nbsp;min) reduced the tumour mass at early time-points up to 30&nbsp;days after treatment, the antitumour effect of (225)Ac-DOTA-F3 (t (1/2) 10&nbsp;days) increased at later time-points. The difference in the fraction of necrotic cells after treatment with (225)Ac-DOTA-F3 (43%) and with (213)Bi-DTPA-F3 (36%) was not significant. Though histological analysis of kidney samples revealed acute tubular necrosis and tubular oedema in 10-30% of animals after treatment with (225)Ac-DOTA-F3 or (213)Bi-DTPA-F3, protein casts were negligible (2%), indicating only minor damage to the kidney. CONCLUSION: Therapy with both (225)Ac-DOTA-F3 and (213)Bi-DTPA-F3 increased survival of mice with peritoneal carcinomatosis. Mild renal toxicity of both constructs favours future therapeutic application

Solving Fair Exchange with Mobile Agents

. Mobile agents have been advocated to support electronic commerce over the Internet. While being a promising paradigm, many intricate problems need to be solved to make this vision reality. The problem of fair exchange between two agents is one such fundamental problem. Informally speaking, this means to exchange two electronic items in such a way that neither agent suffers a disadvantage. We study the problem of fair exchange in the mobile agent paradigm. We show that while existing protocols for fair exchange can be substantially simplified in the context of mobile agents, there are still many problems related to security which remain difficult to solve. We propose three increasingly flexible solutions to the fair exchange problem and show how to implement them using existing agent technology. The basis for ensuring the security properties of fair exchange is a tamper-proof hardware device called a trusted processing environment. 1 Introduction Ever since their emergenc..

A Theory of Fault Recovery for Component-Based Models

International audienceThis paper introduces a theory of fault recovery for component-based models. In our framework, a model is specified in terms of a set of atomic components that are incrementally composed and synchronized by a set of glue operators. We define what it means for such models to provide a recovery mechanism, so that the model converges to its normal behavior in the presence of faults. We identify \emph{corrector} (atomic or composite) components whose presence in a model is essential to guarantee recovery after the occurrence of faults. We also formalize component-based models that effectively \emph{separate} recovery from functional concerns

A Theory of Fault Recovery for Component-Based Models

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(Im)Possibilities of predicate detection in crash-affected systems

In an asynchronous system, where processes can crash, perfect predicate detection for general predicates is difficult to achieve. A general predicate thereby is of the form , where and refer to a normal process variable and to the operational state of that process, respectively. Indeed, the accuracy of predicate detection largely depends on the quality of failure detection. In this paper, we investigate the predicate detection semantics that are achievable for general predicates using either failure detector classes . For this purpose, we introduce weaker variants of the predicate detection problem, which we call stabilizing and infinitely often accurate. We show that perfect predicate detection is impossible using the aforementioned failure detectors. Rather, only allow stabilizing predicate detection. Consequently, we explore alternative approaches to perfect predicate detection: introducing a stronger failure detector, called ordered perfect, or restricting the general nature of predicates