145 research outputs found

    Validation of a finite element model for fracture mechanics specimens

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    Single parameter formulations have shown to be insufficient to describe constraint effects in fracture mechanics specimens. This has lead researchers to a two parameter approach like the J-Q theory. In order to investigate constraint effects, the authors have developed a generic finite element model. Prior to drawing conclusions this model must first be validated, which is the topic of this paper. This validation has been done by comparing analytical expressions of the J-integral with those obtained from the performed simulations. The compared geometries were center cracked tension (CCT) and double edge notched tension (DENT) fracture mechanics specimens. The results showed good agreement with the analytical expressions and, as such, the model can now be confidently applied to determine values of the J-integral. This is a first step towards evaluating two parameter J-Q constraint

    Kangaroo mother care in the community: practices in southern Rwanda

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    Background: The World Health Organization (WHO) guidelines recommend practicing KMC (Kangaroo Mother Care) continuously for weeks after discharge of preterm newborns. However, little is known about KMC practices in the community in Rwanda and other African countries.Therefore, this study sought to assess KMC practices in Southern Rwanda, primarily after hospitalization and identify barriers to KMC in the community.Methods: A cross-sectional study was performed with data collected through a survey among 124 caregivers of preterm infants and Community Health Workers. The Statistical Package for the Social Sciences SPSS version 22 was used to analyze the data.Results: Among all caregivers interviewed, 86.7% confirmed that they practiced KMC, both in the hospital (KABUTARE District Hospital) as well as after discharge, but there is a large variation in practice time and place. KMC is practiced more during daytime. Working in the fields and lack of support to the caregivers are reported most frequently as barriers to practice KMC in the community.Conclusion: KMC-practice is still sub-optimal in Rwanda. Special attention should be directed towards KMCpractice at night and towards the reported obstacles of practicing KMC in the community, e.g. working in the field, lack of support and equipment, difficulties to sleep and health problems.Keywords: Kangaroo Mother Care - Follow-up - Preterm infants – Rwand

    inv(7)(p15q34) - t(7;7)(p15;q34)

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    Review on inv(7)(p15q34) - t(7;7)(p15;q34), with data on clinics, and the genes involved

    Antibiotic resistance and molecular characteristics of methicillin-resistant Staphylococcus epidermidis recovered from hospital personnel in China

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    Objectives Staphylococcus epidermidis is a major nosocomial pathogen predominantly associated with indwelling medical device infections. Studies reporting on S. epidermidis recovered from hospital personnel in China are scarce. The aim of this study was to evaluate the carriage and antibiotic resistance of S. epidermidis among the hospital personnel in Tianjin, China and provide insights into their genetic diversity. Methods 107 S. epidermidis isolates were recovered from 68 hospital personnel in two public hospitals in Tianjin between March 2018 and May 2018. SCCmec types were determined by the combination of mec and ccr complexes. Multi-locus sequence typing was used to determine the sequence types (ST) of S. epidermidis isolates. Results 62 (76.5%) isolates were determined to be methicillin-resistant S. epidermidis (MRSE). 35 (51%) out of 68 hospital personnel carried S. epidermidis, of which 32 (91%) were carriers of MRSE. All 62 MRSE isolates had high levels of resistance to penicillin (90%) and cefoxitin (100%). 37 (60%) isolates carried SCCmec type IV, followed by 15 (24%) carrying SCCmec V, and 4 (6%) SCCmec II. Novel sequence types were assigned to four S. epidermidis isolates (ST832, ST833, ST834 and ST835). Conclusions In this study, the majority of MRSE belonged to cluster II domain of CC2. The ST59-IV was a dominant clone among isolates recovered from hospital personnel. Determination of new MLST types confirmed the genetic diversity of these isolates. These observations highlight the need to review the infection control strategies to reduce the carriage of MRSE among hospital personnel

    Simulating nutrient release from parental carcasses increases the growth, biomass and genetic diversity of juvenile Atlantic salmon

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    The net transport of nutrients by migratory fish from oceans to inland spawning areas has decreased due to population declines and migration barriers. Restoration of nutrients to increasingly oligotrophic upland streams (that were historically salmon spawning areas) have shown short‐term benefits for juvenile salmon, but the longer term consequences are little known. Here we simulated the deposition of a small number of adult Atlantic salmon Salmo salar carcasses at the end of the spawning period in five Scottish upland streams (‘high parental nutrient’ treatment), while leaving five reference streams without carcasses (‘low parental nutrient’ treatment). All streams received exactly the same number of salmon eggs (n = 3,000) drawn in equal number from the same 30 wild‐origin families, thereby controlling for initial egg density and genetic composition. We then monitored the resulting juvenile salmon and their macroinvertebrate prey, repeating the carcass addition treatment in the next spawning season. Macroinvertebrate biomass and abundance were five times higher in the high parental nutrient streams, even 1 year after the carcass addition, and led to faster growth of juvenile salmon over the next 2 years (but with no change in population density). This faster growth led to more fish exceeding the size threshold that would trigger emigration to sea at 2 rather than 3 years of age. There was also higher genetic diversity among surviving salmon in high parental nutrient streams; genotyping showed that these effects were not due to immigration but to differential survival. Synthesis and applications. This 2‐year field experiment shows that adding nutrients that simulate the presence of small numbers of adult salmon carcasses can have long‐term effects on the growth rate of juvenile salmon, likely increasing the number that will migrate to sea early and also increasing their genetic diversity. However, the feasibility of adding nutrients to spawning streams as a management tool to boost salmon populations will depend on whether the benefits at this stage are maintained over the entire life cycle

    Simulating nutrient release from parental carcasses increases the growth, biomass and genetic diversity of juvenile Atlantic salmon

    Get PDF
    The net transport of nutrients by migratory fish from oceans to inland spawning areas has decreased due to population declines and migration barriers. Restoration of nutrients to increasingly oligotrophic upland streams (that were historically salmon spawning areas) have shown short‐term benefits for juvenile salmon, but the longer term consequences are little known. Here we simulated the deposition of a small number of adult Atlantic salmon Salmo salar carcasses at the end of the spawning period in five Scottish upland streams (‘high parental nutrient’ treatment), while leaving five reference streams without carcasses (‘low parental nutrient’ treatment). All streams received exactly the same number of salmon eggs (n = 3,000) drawn in equal number from the same 30 wild‐origin families, thereby controlling for initial egg density and genetic composition. We then monitored the resulting juvenile salmon and their macroinvertebrate prey, repeating the carcass addition treatment in the next spawning season. Macroinvertebrate biomass and abundance were five times higher in the high parental nutrient streams, even 1 year after the carcass addition, and led to faster growth of juvenile salmon over the next 2 years (but with no change in population density). This faster growth led to more fish exceeding the size threshold that would trigger emigration to sea at 2 rather than 3 years of age. There was also higher genetic diversity among surviving salmon in high parental nutrient streams; genotyping showed that these effects were not due to immigration but to differential survival. Synthesis and applications. This 2‐year field experiment shows that adding nutrients that simulate the presence of small numbers of adult salmon carcasses can have long‐term effects on the growth rate of juvenile salmon, likely increasing the number that will migrate to sea early and also increasing their genetic diversity. However, the feasibility of adding nutrients to spawning streams as a management tool to boost salmon populations will depend on whether the benefits at this stage are maintained over the entire life cycle

    EVI1 overexpression in t(3;17) positive myeloid malignancies results from juxtaposition of EVI1 to the MSI2 locus at 17q22

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    Chromosomal translocations involving the EVI1 locus are a recurrent finding in myeloid leukemia and are associated with poor prognosis. In this study, we performed a detailed molecular characterization of the recurrent translocation t(3;17)(q26;q22) in 13 hematologic malignancies. The EVI1 gene locus was rearranged in all 13 patients and was associated with EVI1 overexpression. In 9 out of 13 patients, the 17q breakpoints clustered in a 250 kb region on band 17q22 encompassing the MSI2 (musashi homologue 2) gene. Expression analyses failed to demonstrate ectopic MSI2 expression or the presence of an MSI2/EVI1 fusion gene. In conclusion, we show for the first time that the t(3;17) is indeed a recurrent chromosomal aberration in myeloid malignancies. In keeping with findings in other recurrent 3q26 rearrangements, overexpression of the EVI1 gene appears to be the major contributor to leukemogenesis in patients with a t(3; 17)

    EVI1 activation in blast crisis CML due to juxtaposition to the rare 17q22 partner region as part of a 4-way variant translocation t(9;22)

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    <p>Abstract</p> <p>Background</p> <p>Variant translocations t(9;22) occur in 5 to 10% of newly diagnosed CMLs and additional genetic changes are present in 60–80% of patients in blast crisis (BC). Here, we report on a CML patient in blast crisis presenting with a four-way variant t(9;22) rearrangement involving the <it>EVI1 </it>locus.</p> <p>Methods</p> <p>Dual-colour Fluorescence In Situ Hybridisation was performed to unravel the different cytogenetic aberrations. Expression levels of <it>EVI1 </it>and <it>BCR/ABL1 </it>were investigated using real-time quantitative RT-PCR.</p> <p>Results</p> <p>In this paper we identified a patient with a complex 4-way t(3;9;17;22) which, in addition to <it>BCR/ABL1 </it>gene fusion, also resulted in <it>EVI1 </it>rearrangement and overexpression.</p> <p>Conclusion</p> <p>This report illustrates how a variant t(9;22) translocation can specifically target a second oncogene most likely contributing to the more aggressive phenotype of the disease. Molecular analysis of such variants is thus warranted to understand the phenotypic consequences and to open the way for combined molecular therapies in order to tackle the secondary oncogenic effect which is unresponsive to imatinib treatment.</p
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