206 research outputs found

    Prevalence of scoliosis and impaired pulmonary function in patients with type III osteogenesis imperfecta

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    Purpose: Osteogenesis Imperfecta (OI) is a rare group of congenital genetic disorders that consists of a collagen synthesis defect. The most severe phenotype is type III OI. Characterized by progressive bone deformity, fragility and pulmonary impairment, causing significant morbidity and mortality. Also, multilevel spine deformities are observed, such as scoliosis. The literature on the pathophysiology of pulmonary impairment in relation to scoliosis in these patients is scarce and conflicting. This study aims to determine the prevalence of scoliosis and its relation to pulmonary function in type III OI patients. Methods: This retrospective cohort study took place between April 2020 and November 2021. Forty-two patients with type III OI were included. Anterior–posterior spine radiographs were evaluated for scoliosis. Pulmonary function was assessed using spirometry and partial pressure of carbon dioxide. Results: All 42 patients had scoliosis, with a mean curve of 66° (95% CI of range). Vital lung capacity was decreased, compared to a non-OI population (mean 1.57 L). This was correlated to the degree of scoliosis (st. β − 0.40, P = 0.03), especially in increasing thoracic curves. Restrictive lung pathophysiology was shown in our study population with a mean FEV1/FVC ratio of 0.85. Conclusions: Increasing thoracic scoliosis was correlated with decreased vital lung capacity in our study population of type III OI patients. High FEV1/FVC ratios found in this study population show restrictive lung pathophysiology. Therefore, it is plausible that the pulmonary impairment found in type III OI patients is a combined issue, partly associated to scoliosis and partly intrinsic to OI

    Customizable and scalable automated assessment of C/C++ programming assignments

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    The correction of exercises in programming courses is a laborious task that has traditionally been performed in a manual way. This situation, in turn, delays the access by students to feedback that can contribute significantly to their training as future professionals. Over the years, several approaches have been proposed to automate the assessment of students' programs. Static analysis is a known technique that can partially simulate the process of manual code review performed by lecturers. As such, it is a plausible option to assess whether students' solutions meet the requirements imposed on the assignments. However, implementing a personalized analysis beyond the rules included in existing tools may be a complex task for the lecturer without a mechanism that guides the work. In this paper, we present a method to provide automated and specific feedback to immediately inform students about their mistakes in programming courses. To that end, we developed the CAC++ library, which enables constructing tailored static analysis programs for C/C++ practices. The library allows for great flexibility and personalization of verifications to adjust them to each particular task, overcoming the limitations of most of the existing assessment tools. Our approach to providing specific feedback has been evaluated for a period of three academic years in a course related to object-oriented programming. The library allowed lecturers to reduce the size of the static analysis programs developed for this course. During this period, the academic results improved and undergraduates positively valued the aid offered when undertaking the implementation of assignments.Universidad de Cádiz, Grant/Award Numbers: sol-201500054192-tra, sol-201600064680-tra; Ministerio de Ciencia, Innovación y Universidades, Grant/Award Number: RTI2018-093608-B-C33; European Regional Development Fun

    Repositioning the Catalytic Triad Aspartic Acid of Haloalkane Dehalogenase: Effects on Stability, Kinetics, and Structure

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    Haloalkane dehalogenase (DhlA) catalyzes the hydrolysis of haloalkanes via an alkyl-enzyme intermediate. The covalent intermediate, which is formed by nucleophilic substitution with Asp124, is hydrolyzed by a water molecule that is activated by His289. The role of Asp260, which is the third member of the catalytic triad, was studied by site-directed mutagenesis. Mutation of Asp260 to asparagine resulted in a catalytically inactive D260N mutant, which demonstrates that the triad acid Asp260 is essential for dehalogenase activity. Furthermore, Asp260 has an important structural role, since the D260N enzyme accumulated mainly in inclusion bodies during expression, and neither substrate nor product could bind in the active-site cavity. Activity for brominated substrates was restored to D260N by replacing Asn148 with an aspartic or glutamic acid. Both double mutants D260N+N148D and D260N+N148E had a 10-fold reduced kcat and 40-fold higher Km values for 1,2-dibromoethane compared to the wild-type enzyme. Pre-steady-state kinetic analysis of the D260N+N148E double mutant showed that the decrease in kcat was mainly caused by a 220-fold reduction of the rate of carbon-bromine bond cleavage and a 10-fold decrease in the rate of hydrolysis of the alkyl-enzyme intermediate. On the other hand, bromide was released 12-fold faster and via a different pathway than in the wild-type enzyme. Molecular modeling of the mutant showed that Glu148 indeed could take over the interaction with His289 and that there was a change in charge distribution in the tunnel region that connects the active site with the solvent. On the basis of primary structure similarity between DhlA and other α/β-hydrolase fold dehalogenases, we propose that a conserved acidic residue at the equivalent position of Asn148 in DhlA is the third catalytic triad residue in the latter enzymes.

    Atomic layer deposition of high-k dielectric layers on Ge and III-V MOS channels

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    Ge and III-V semiconductors are potential high performance channel materials for future CMOS devices. In this work, we have studied At. Layer Deposition (ALD) of high-k dielec. layers on Ge and GaAs substrates. We focus at the effect of the oxidant (H2O, O3, O2, O2 plasma) during gate stack formation. GeO2, obtained by Ge oxidn. in O2 or O3, is a promising passivation layer. The germanium oxide thickness can be scaled down below 1 nm, but such thin layers contain Ge in oxidn. states lower than 4+. Still, elec. results indicate that small amts. of Ge in oxidn. states lower than 4+ are not detrimental for device performance. Partial intermixing was obsd. for high-k dielec. and GeO2 or GaAsOx, suggesting possible correlations in the ALD growth mechanisms on Ge and GaAs substrates. [on SciFinder (R)

    Measuring the activity of European and African Countries using Social Accounting Matrices

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    Economic models at the micro, meso and macro levels presuppose the existence of consistent databases that make it possible to quantify the activity of enterprises, sectors, regions, countries or continents. Such models can also be important aids in the policy decision process, since they permit the construction of scenarios resulting from the adoption of policy measures and the consequent changes that they introduce. When consistent with the United Nations System of National Accounts (SNA), the Social Accounting Matrix (SAM) can include all the nominal flows of the measured part of the economy, at the level of both production and the institutions, and therefore satisfies these requirements. Thus, in its numerical version, a SAM constitutes a database and provides a snapshot of the measured reality at a certain moment, whereas its possible algebraic versions, i.e. models that are based upon it, permit the construction of the above-mentioned scenarios. The possibility and usefulness of constructing SAMs for African countries consistent with the SNA will be examined and experimented. The SAM’s basic structure and consistency within the whole system will be studied, as well as any possible disaggregations, extensions, aggregates, indicators and balances that can be calculated. Other aspects beyond that basic structure will also be examined in order to show to what extent the SAM is capable of covering parts of the economy that are not covered by the SNA.info:eu-repo/semantics/publishedVersio

    Socio-economic studies with social accounting and sociodemographic matrices : an application to Portugal.

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    In looking for empirical evidence about the activity of countries, a proposal is made for studying (measuring and modelling) the activity of countries through the use of Social Accounting Matrices (SAMs) and Socio-Demographic Matrices (SDMs). SAMs and SDMs are presented as tools that have specific features for conducting studies in several different areas, as well as for supporting policy decision processes. Based on methodological principles that are derived mainly from the works of Richard Stone, emphasis is placed on the desirability of working in a matrix format, which includes not only people (SDM), but also, at the same time, activities, products, factors of production and institutions (SAM). This is considered to be a way of capturing the relevant network of linkages and the corresponding multiplier effects, which can be used for the subsequent modelling of the activity of the countries studied. A method will be proposed for the construction of these matrices. In the case of the SAMs, it is proposed that their design and construction should adopt, at least as their starting point, the latest version of the System of National Accounts (2008 SNA) and the corresponding results of its adoption/adaptation by different countries. The exposition of this proposal is accompanied by an example applied to Portugal.Financial support provided by FCT (Fundação para a Ciência e a Tecnologia)Portugal for the research and writing of this article, which forms part of the Strategic Project for 2011-13 (PEst- OE/EGE/UI0436/2011)
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