434 research outputs found

    Simulation of weather-driven deterioration of clay embankments

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    Clay embankments used for road, rail, and flood defense infrastructure experience several weather-driven deterioration processes that lead to a progressive degradation in their hydromechanical performance. This paper presents a numerical modeling approach that accounts for the development of desiccation cracking in clay embankments. Specifically, a bimodal soil water retentivity model was adopted to capture the long-term hydraulic behavior of clay embankments prone to weather-driven desiccation cracking. A numerical model was developed for a heavily instrumented and monitored full-scale research embankment with long-term field data. The model was able to capture the variation of near-surface soil moisture and matric suction over a monitored period of nine years in response to weather cycles. The developed and validated numerical modeling approach enables forecasting of the long-term performance of clay embankments under a range of future climate scenarios

    Chromosomal Rearrangements Formed by rrn Recombination Do Not Improve Replichore Balance in Host-Specific Salmonella enterica Serovars

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    operons. One hypothesis explaining these rearrangements suggests that replichore imbalance introduced from horizontal transfer of pathogenicity islands and prophages drives chromosomal rearrangements in an attempt to improve balance.This hypothesis was directly tested by comparing the naturally-occurring chromosomal arrangement types to the theoretically possible arrangement types, and estimating their replichore balance using a calculator. In addition to previously characterized strains belonging to host-specific serovars, the arrangement types of 22 serovar Gallinarum strains was also determined. Only 48 out of 1,440 possible arrangement types were identified in 212 host-specific strains. While the replichores of most naturally-occurring arrangement types were well-balanced, most theoretical arrangement types had imbalanced replichores. Furthermore, the most common types of rearrangements did not change replichore balance.The results did not support the hypothesis that replichore imbalance causes these rearrangements, and suggest that the rearrangements could be explained by aspects of a host-specific lifestyle

    Power grip, pinch grip, manual muscle testing or thenar atrophy - which should be assessed as a motor outcome after carpal tunnel decompression? A systematic review

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    <p>Abstract</p> <p>Background</p> <p>Objective assessment of motor function is frequently used to evaluate outcome after surgical treatment of carpal tunnel syndrome (CTS). However a range of outcome measures are used and there appears to be no consensus on which measure of motor function effectively captures change. The purpose of this systematic review was to identify the methods used to assess motor function in randomized controlled trials of surgical interventions for CTS. A secondary aim was to evaluate which instruments reflect clinical change and are psychometrically robust.</p> <p>Methods</p> <p>The bibliographic databases Medline, AMED and CINAHL were searched for randomized controlled trials of surgical interventions for CTS. Data on instruments used, methods of assessment and results of tests of motor function was extracted by two independent reviewers.</p> <p>Results</p> <p>Twenty-two studies were retrieved which included performance based assessments of motor function. Nineteen studies assessed power grip dynamometry, fourteen studies used both power and pinch grip dynamometry, eight used manual muscle testing and five assessed the presence or absence of thenar atrophy. Several studies used multiple tests of motor function. Two studies included both power and pinch strength and reported descriptive statistics enabling calculation of effect sizes to compare the relative responsiveness of grip and pinch strength within study samples. The study findings suggest that tip pinch is more responsive than lateral pinch or power grip up to 12 weeks following surgery for CTS.</p> <p>Conclusion</p> <p>Although used most frequently and known to be reliable, power and key pinch dynamometry are not the most valid or responsive tools for assessing motor outcome up to 12 weeks following surgery for CTS. Tip pinch dynamometry more specifically targets the thenar musculature and appears to be more responsive. Manual muscle testing, which in theory is most specific to the thenar musculature, may be more sensitive if assessed using a hand held dynamometer – the Rotterdam Intrinsic Handheld Myometer. However further research is needed to evaluate its reliability and responsiveness and establish the most efficient and psychometrically robust method of evaluating motor function following surgery for CTS.</p

    Classic Kaposi's sarcoma in morocco: clinico -epidemiological study at the national institute of oncology

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    <p>Abstract</p> <p>Background</p> <p>Classic Kaposi's sarcoma (CKS) is a rare disease likely associated with human herpes virus 8 (HHV-8) infection, and occurs predominantly in Jewish, Mediterranean and middle eastern men .There is a dearth of data in Moroccan patients with CKS regarding epidemiology, clinical characteristics and outcomes. This report examines a cohort of patients with CKS evaluated at the national institute of oncology over 11-year period.</p> <p>Methods</p> <p>A retrospective analysis of patients referred to the national institute of oncology with classical Kaposi sarcoma, between January 1998 and February 2008, was performed. Reviewed information included demographics, clinical and pathological staging, death or last follow-up.</p> <p>Results</p> <p>During the study period, 56 patients with a diagnosis of CKS have been referred to our hospital. There were 11(19,7%) females and 45 (80,3%) males (male-to-female ratio: 4:1). Mean age at diagnosis was 61,7 ± 15 (range: 15- 86 years). Nodules and/or plaques were the most frequent type of lesion. The most common location was the lower limbs, particularly the distal lower extremity (90%). In addition to skin involvement, visceral spread was evident in 9 cases. The most common visceral involvement sites were lymph nodes (44%), lung (22%), and gastrointestinal tract (22%). Associated lymphoedema was seen in 24 (42%) of the patients. There were 18 stage I patients (32,14%), 8: stage II (14,28%), 21 stage III(37,5%) and 9 stage IV (16,07%). A second primary malignancy was diagnosed in 6 cases (10,7%), none of the reticuloendothelial system.</p> <p>With a median follow-up of 45 months, 38 (67,8) patients are alive, of whom 25 (65,78%) patients with stable disease, five with progressive disease currently under systemic chemotherapy and 8(21,05%) are alive and free of disease, over a mean interval of 5 years.</p> <p>Conclusion</p> <p>This is the largest reported series in our context. In Morocco, CKS exhibits some special characteristics including a disseminated skin disease at diagnosis especially in men, a more common visceral or lymph node involvement and a less frequent association with second malignancies.</p

    Virtual interactive musculoskeletal system (VIMS) in orthopaedic research, education and clinical patient care

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    The ability to combine physiology and engineering analyses with computer sciences has opened the door to the possibility of creating the "Virtual Human" reality. This paper presents a broad foundation for a full-featured biomechanical simulator for the human musculoskeletal system physiology. This simulation technology unites the expertise in biomechanical analysis and graphic modeling to investigate joint and connective tissue mechanics at the structural level and to visualize the results in both static and animated forms together with the model. Adaptable anatomical models including prosthetic implants and fracture fixation devices and a robust computational infrastructure for static, kinematic, kinetic, and stress analyses under varying boundary and loading conditions are incorporated on a common platform, the VIMS (Virtual Interactive Musculoskeletal System). Within this software system, a manageable database containing long bone dimensions, connective tissue material properties and a library of skeletal joint system functional activities and loading conditions are also available and they can easily be modified, updated and expanded. Application software is also available to allow end-users to perform biomechanical analyses interactively. Examples using these models and the computational algorithms in a virtual laboratory environment are used to demonstrate the utility of these unique database and simulation technology. This integrated system, model library and database will impact on orthopaedic education, basic research, device development and application, and clinical patient care related to musculoskeletal joint system reconstruction, trauma management, and rehabilitation

    TRY plant trait database - enhanced coverage and open access

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    Plant traits-the morphological, anatomical, physiological, biochemical and phenological characteristics of plants-determine how plants respond to environmental factors, affect other trophic levels, and influence ecosystem properties and their benefits and detriments to people. Plant trait data thus represent the basis for a vast area of research spanning from evolutionary biology, community and functional ecology, to biodiversity conservation, ecosystem and landscape management, restoration, biogeography and earth system modelling. Since its foundation in 2007, the TRY database of plant traits has grown continuously. It now provides unprecedented data coverage under an open access data policy and is the main plant trait database used by the research community worldwide. Increasingly, the TRY database also supports new frontiers of trait-based plant research, including the identification of data gaps and the subsequent mobilization or measurement of new data. To support this development, in this article we evaluate the extent of the trait data compiled in TRY and analyse emerging patterns of data coverage and representativeness. Best species coverage is achieved for categorical traits-almost complete coverage for 'plant growth form'. However, most traits relevant for ecology and vegetation modelling are characterized by continuous intraspecific variation and trait-environmental relationships. These traits have to be measured on individual plants in their respective environment. Despite unprecedented data coverage, we observe a humbling lack of completeness and representativeness of these continuous traits in many aspects. We, therefore, conclude that reducing data gaps and biases in the TRY database remains a key challenge and requires a coordinated approach to data mobilization and trait measurements. This can only be achieved in collaboration with other initiatives

    A bi-articular model for scapular-humeral rhythm reconstruction through data from wearable sensors

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    Patient-specific performance assessment of arm movements in daily life activities is fundamental for neurological rehabilitation therapy. In most applications, the shoulder movement is simplified through a socket-ball joint, neglecting the movement of the scapular-thoracic complex. This may lead to significant errors. We propose an innovative bi-articular model of the human shoulder for estimating the position of the hand in relation to the sternum. The model takes into account both the scapular-toracic and gleno-humeral movements and their ratio governed by the scapular-humeral rhythm, fusing the information of inertial and textile-based strain sensors

    Advantages of a Polycentric Approach to Climate Change Policy

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    Lack of progress in global climate negotiations has led scholars to reconsider polycentric approaches to climate policy. Several examples of subglobal mechanisms to reduce greenhouse-gas emissions have been touted, but it remains unclear why they might achieve better climate outcomes than global negotiations alone. Decades of work conducted by researchers associated with the Vincent and Elinor Ostrom Workshop in Political Theory and Policy Analysis at Indiana University have emphasized two chief advantages of polycentric approaches over monocentric ones: they provide more opportunities for experimentation and learning to improve policies over time, and they increase communications and interactions — formal and informal, bilateral and multilateral — among parties to help build the mutual trust needed for increased cooperation. A wealth of theoretical, empirical and experimental evidence supports the polycentric approach

    Lumazine Synthase Protein Nanoparticle-Gd(III)-DOTA Conjugate as a T1 contrast agent for high-field MRI

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    With the applications of magnetic resonance imaging (MRI) at higher magnetic fields increasing, there is demand for MRI contrast agents with improved relaxivity at higher magnetic fields. Macromolecule-based contrast agents, such as protein-based ones, are known to yield significantly higher r(1) relaxivity at low fields, but tend to lose this merit when used as T-1 contrast agents (r(1)/r(2) = 0.5 similar to 1), with their r(1) decreasing and r(2) increasing as magnetic field strength increases. Here, we developed and characterized an in vivo applicable magnetic resonance (MR) positive contrast agent by conjugating Gd(III)-chelating agent complexes to lumazine synthase isolated from Aquifex aeolicus (AaLS). The r(1) relaxivity of Gd(III)-DOTA-AaLS-R108C was 16.49 mM(-1)s(-1) and its r(1)/r(2) ratio was 0.52 at the magnetic field strength of 7 T. The results of 3D MR angiography demonstrated the feasibility of vasculature imaging within 2 h of intravenous injection of the agent and a significant reduction in T-1 values were observed in the tumor region 7 h post-injection in the SCC-7 flank tumor model. Our findings suggest that Gd(III)-DOTA-AaLS-R108C could serve as a potential theranostic nanoplatform at high magnetic field strength.open0
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