166 research outputs found

    Spectroscopy and dissociative recombination of the lowest rotational states of H3+

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    The dissociative recombination of the lowest rotational states of H3+ has been investigated at the storage ring TSR using a cryogenic 22-pole radiofrequency ion trap as injector. The H3+ was cooled with buffer gas at ~15 K to the lowest rotational levels, (J,G)=(1,0) and (1,1), which belong to the ortho and para proton-spin symmetry, respectively. The rate coefficients and dissociation dynamics of H3+(J,G) populations produced with normal- and para-H2 were measured and compared to the rate and dynamics of a hot H3+ beam from a Penning source. The production of cold H3+ rotational populations was separately studied by rovibrational laser spectroscopy using chemical probing with argon around 55 K. First results indicate a ~20% relative increase of the para contribution when using para-H2 as parent gas. The H3+ rate coefficient observed for the para-H2 source gas, however, is quite similar to the H3+ rate for the normal-H2 source gas. The recombination dynamics confirm that for both source gases, only small populations of rotationally excited levels are present. The distribution of 3-body fragmentation geometries displays a broad part of various triangular shapes with an enhancement of ~12% for events with symmetric near-linear configurations. No large dependences on internal state or collision energy are found.Comment: 10 pages, 9 figures, to be published in Journal of Physics: Conference Proceeding

    Dietary phytase effects on copper requirements of broilers

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    Information on the availability of Cu from plant feedstuffs for broilers in the presence of phytase is scarce. The present research has been conducted with the objective of evaluating the Cu requirements of broilers when fed corn-soy diets with or without phytase. A total of 640 one-day-old male Cobb x Cobb 500, allocated into 80 battery cages with 8 chicks in each, were fed a low Cu content diet (formulated with 8.58 ± 0.21 mg/kg Cu) without phytase from placement to day 7. Starting on day 8, battery cages were distributed into a 2 × 5 factorial arrangement (phytase-added diets X 5 with graded increases of supplemental Cu) until day 28. Feeding treatments (feeds added or not with phytase and 5 graded increases of Cu) were randomly distributed with 8 cages of 8 chicks. The basal non-supplemented feeds were formulated with corn and soybean meal (SBM) without any other significant Cu contributors. Supplemental Cu was from laboratory-grade Cu sulfate pentahydrate (CuSO5H20) which was increasingly added to the feeds. Phytase was added in excess to the producer recommendation (2,500 FYT) and had average analyzed values of 2,768 ± 135.2 FYT/kg whereas analyzed Cu values were: 8.05 ± 0.25, 11.25 ± 0.15, 14.20 ± 0.40, 16.55 ± 0.05, and 19.45 ± 0.45 mg/kg. Statistics were conducted using linear and quadratic polynomial regression models. No interactions occurred between dietary Cu and phytase (p > 0.05) for any response and no effects were found for the individual factors (phytase or dietary Cu) for Ht, Hb, varus, valgus, rotated tibia, and tibia breaking strength, as well as for Cu contents in breast, gastrocnemius tendon, and kidney (p > 0.05). However, the phytase-added diets led to higher BWG, lower FCR, and increased ileal digestible Cu (p < 0.05). The gradual increase in dietary Cu produced linear increases in Cu content in livers, as well as in excreta and retention (p < 0.05). Supplementing phytase at levels expected to maximize phytate degradation was demonstrated to improve BWG and FCR; however, no effects were observed when dietary Cu was increased to a maximum of 19.45 mg/kg. An increase of 8.8% in ileal digestible Cu was observed when birds were fed phytase

    L1CAM Expression is Related to Non-Endometrioid Histology, and Prognostic for Poor Outcome in Endometrioid Endometrial Carcinoma

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    The majority of endometrial carcinomas are classified as Type I endometrioid endometrial carcinomas (EECs) and have a good prognosis. Type II non-endometrioid endometrial carcinomas (NEECs) have a significant worse outcome. Yet, 20 % of the EECs are associated with an unexplained poor outcome. The aim of this study was to determine if L1CAM expression, a recently reported biomarker for aggressive tumor behavior in endometrial carcinoma, was associated with clinicopathological features of EECs. A total of 103 patients diagnosed as EEC at the Radboud University Medical Centre, based on the pathology report were selected. L1CAM status of these tumors was determined, and histologic slides were reviewed by two expert pathologists. L1CAM-positivity was observed in 17 % (18/103). Review of the diagnostic slides revealed that 11 out of these 18 L1CAM-positive tumors (61 %) contained a serous- or mixed carcinoma component that was not initially mentioned in the pathology report. L1CAM-expression was associated with advanced age, poor tumor grade, and lymphovascular space invasion. A worse five year progression free survival rate was observed for patients with L1CAM-positive tumors (55.6 % for the L1CAM-positive group, compared to 83.3 % for the L1CAM-negative group P = 0.01). L1CAM expression carries prognostic value for histologically classified EEC and supports the identification of tumors with a NEEC component. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1007/s12253-016-0047-8) contains supplementary material, which is available to authorized users

    Protocol for a systematic review of guidelines for rigour in the design, conduct and analysis of biomedical experiments involving laboratory animals

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    Objective: Within the last years, there has been growing awareness of the negative repercussions of unstandardized planning, conduct and reporting of preclinical and biomedical research. Several initiatives have set the aim of increasing validity and reliability in reporting of studies and publications, and publishers have formed similar groups. Additionally, several groups of experts across the biomedical spectrum have published experience and opinion-based guidelines and guidance on potential standardized reporting. While all these guidelines cover reporting of experiments, an important step prior to this should be rigours planning and conduction of studies. The aim of this systematic review is to identify and harmonize existing experimental design, conduct and analysis guidelines relating to internal validity and reproducibility of preclinical animal research. The review will also identify literature describing risks of bias pertaining to the design, conduct and analysis of preclinical biomedical research. Search strategy: PubMed, Embase and Web of Science will be searched systematically to identify guidelines published in English language in peer-reviewed journals before January 2018 (box 1). All articles or systematic reviews in English language that describe or review guidelines on the internal validity and reproducibility of animal studies will be included. Google search for guidelines published on the websites of major funders and professional organisations can be found in (Box 2). Screening and annotation: Unique references will be screened in two phases: screening for eligibility based on title and abstract, followed by screening for definitive inclusion based on full text. Screening will be performed in SyRF (http://syrf.org.uk). Each reference will be randomly presented to two independent reviewers. Disagreements between reviewers will be resolved by additional screening of the reference by a third, senior researcher. Data management and reporting: All data, including extracted text and guidelines, will be stored in the SyRF platform. Elements of the included guidelines will be identified using a standardized extraction form. Reporting will follow the PRISMA guidelines as far as applicable

    Resonant structure of low-energy H3+ dissociative recombination

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    New high-resolution dissociative recombination rate coefficients of rotationally cool and hot H3+ in the vibrational ground state have been measured with a 22-pole trap setup and a Penning ion source, respectively, at the ion storage ring TSR. The experimental results are compared with theoretical calculations to explore the dependence of the rate coefficient on ion temperature and to study the contributions of different symmetries to probe the rich predicted resonance spectrum. The break-up energy was investigated by fragment imaging to derive internal temperatures of the stored parent ions under differing experimental conditions. A systematic experimental assessment of heating effects is performed which, together with a survey of other recent storage-ring data, suggests that the present rotationally cool rate-coefficient measurement was performed at 380^{+50}_{-130} K and that this is the lowest rotational temperature so far realized in storage-ring rate-coefficient measurements on H3+. This partially supports the theoretical suggestion that higher temperatures than assumed in earlier experiments are the main cause for the large gap between the experimental and theoretical rate coefficients. For the rotationally hot rate-coefficient measurement a temperature of below 3250K is derived. From these higher-temperature results it is found that increasing the rotational ion temperature in the calculations cannot fully close the gap between the theoretical and experimental rate coefficients.Comment: 12 pages, 7 figures (11 subfigures), 3 table

    Assignment of resonances in dissociative recombination of HD+ ions: high-resolution measurements compared with accurate computations

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    The collision-energy resolved rate coefficient for dissociative recombination of HD+ ions in the vibrational ground state is measured using the photocathode electron target at the heavy-ion storage ring TSR. Rydberg resonances associated with ro-vibrational excitation of the HD+ core are scanned as a function of the electron collision energy with an instrumental broadening below 1 meV in the low-energy limit. The measurement is compared to calculations using multichannel quantum defect theory, accounting for rotational structure and interactions and considering the six lowest rotational energy levels as initial ionic states. Using thermal equilibrium level populations at 300 K to approximate the experimental conditions, close correspondence between calculated and measured structures is found up to the first vibrational excitation threshold of the cations near 0.24 eV. Detailed assignments, including naturally broadened and overlapping Rydberg resonances, are performed for all structures up to 0.024 eV. Resonances from purely rotational excitation of the ion core are found to have similar strengths as those involving vibrational excitation. A dominant low-energy resonance is assigned to contributions from excited rotational states only. The results indicate strong modifications in the energy dependence of the dissociative recombination rate coefficient through the rotational excitation of the parent ions, and underline the need for studies with rotationally cold species to obtain results reflecting low-temperature ionized media.Comment: 15 pages, 10 figures. Paper to appear in Phys. Rev. A (version as accepted

    Pathologic and Phenotypic Alterations in a Mouse Expressing a Connexin47 Missense Mutation That Causes Pelizaeus-Merzbacher–Like Disease in Humans

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    Gap junction channels are intercellular conduits that allow diffusional exchange of ions, second messengers, and metabolites. Human oligodendrocytes express the gap junction protein connexin47 (Cx47), which is encoded by the GJC2 gene. The autosomal recessive mutation hCx47M283T causes Pelizaeus-Merzbacher–like disease 1 (PMLD1), a progressive leukodystrophy characterized by hypomyelination, retarded motor development, nystagmus, and spasticity. We introduced the human missense mutation into the orthologous position of the mouse Gjc2 gene and inserted the mCx47M282T coding sequence into the mouse genome via homologous recombination in embryonic stem cells. Three-week-old homozygous Cx47M282T mice displayed impaired rotarod performance but unchanged open-field behavior. 10-15-day-old homozygous Cx47M282T and Cx47 null mice revealed a more than 80% reduction in the number of cells participating in glial networks after biocytin injections into oligodendrocytes in sections of corpus callosum. Homozygous expression of mCx47M282T resulted in reduced MBP expression and astrogliosis in the cerebellum of ten-day-old mice which could also be detected in Cx47 null mice of the same age. Three-month-old homozygous Cx47M282T mice exhibited neither altered open-field behavior nor impaired rotarod performance anymore. Adult mCx47M282T expressing mice did not show substantial myelin alterations, but homozygous Cx47M282T mice, additionally deprived of connexin32, which is also expressed in oligodendrocytes, died within six weeks after birth and displayed severe myelin defects accompanied by astrogliosis and activated microglia. These results strongly suggest that PMLD1 is caused by the loss of Cx47 channel function that results in impaired panglial coupling in white matter tissue

    Interaction and uptake of exosomes by ovarian cancer cells

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    <p>Abstract</p> <p>Background</p> <p>Exosomes consist of membrane vesicles that are secreted by several cell types, including tumors and have been found in biological fluids. Exosomes interact with other cells and may serve as vehicles for the transfer of protein and RNA among cells.</p> <p>Methods</p> <p>SKOV3 exosomes were labelled with carboxyfluoresceine diacetate succinimidyl-ester and collected by ultracentrifugation. Uptake of these vesicles, under different conditions, by the same cells from where they originated was monitored by immunofluorescence microscopy and flow cytometry analysis. Lectin analysis was performed to investigate the glycosylation properties of proteins from exosomes and cellular extracts.</p> <p>Results</p> <p>In this work, the ovarian carcinoma SKOV3 cell line has been shown to internalize exosomes from the same cells via several endocytic pathways that were strongly inhibited at 4°C, indicating their energy dependence. Partial colocalization with the endosome marker EEA1 and inhibition by chlorpromazine suggested the involvement of clathrin-dependent endocytosis. Furthermore, uptake inhibition in the presence of 5-ethyl-N-isopropyl amiloride, cytochalasin D and methyl-beta-cyclodextrin suggested the involvement of additional endocytic pathways. The uptake required proteins from the exosomes and from the cells since it was inhibited after proteinase K treatments. The exosomes were found to be enriched in specific mannose- and sialic acid-containing glycoproteins. Sialic acid removal caused a small but non-significant increase in uptake. Furthermore, the monosaccharides D-galactose, α-L-fucose, α-D-mannose, D-N-acetylglucosamine and the disaccharide β-lactose reduced exosomes uptake to a comparable extent as the control D-glucose.</p> <p>Conclusions</p> <p>In conclusion, exosomes are internalized by ovarian tumor cells via various endocytic pathways and proteins from exosomes and cells are required for uptake. On the other hand, exosomes are enriched in specific glycoproteins that may constitute exosome markers. This work contributes to the knowledge about the properties and dynamics of exosomes in cancer.</p

    Emergency department triage: an ethical analysis

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    <p>Abstract</p> <p>Background</p> <p>Emergency departments across the globe follow a triage system in order to cope with overcrowding. The intention behind triage is to improve the emergency care and to prioritize cases in terms of clinical urgency.</p> <p>Discussion</p> <p>In emergency department triage, medical care might lead to adverse consequences like delay in providing care, compromise in privacy and confidentiality, poor physician-patient communication, failing to provide the necessary care altogether, or even having to decide whose life to save when not everyone can be saved. These consequences challenge the ethical quality of emergency care. This article provides an ethical analysis of "routine" emergency department triage. The four principles of biomedical ethics - viz. respect for autonomy, beneficence, nonmaleficence and justice provide the starting point and help us to identify the ethical challenges of emergency department triage. However, they do not offer a <it>comprehensive </it>ethical view. To address the ethical issues of emergency department triage from a more comprehensive ethical view, the care ethics perspective offers additional insights.</p> <p>Summary</p> <p>We integrate the results from the analysis using four principles of biomedical ethics into care ethics perspective on triage and propose an integrated clinically and ethically based framework of emergency department triage planning, as seen from a comprehensive ethics perspective that incorporates both the principles-based and care-oriented approach.</p
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