Protein and energy intake, nitrogen balance and nitrogen losses in patients treated with continuous ambulatory peritoneal dialysis

Protein and energy intake, nitrogen balance and nitrogen losses in patients treated with continuous ambulatory peritoneal dialysis. The aim of this investigation was to analyze factors which influence the dietary protein intake (DPI), the energy intake and the utilization of ingested protein, and to determine the relationship between various types of nitrogen losses in stable continuous ambulatory peritoneal dialysis (CAPD) patients. We performed 23 nitrogen balance (NB) studies of 6 to 11 days duration in 12 CAPD patients. One study was performed in all patients 3.4 ± 1.2 months after starting CAPD (early studies). The study was then repeated in nine patients after 12.1 ± 2.6 months, and two of these patients were studied again after 16 and 24 months, respectively (late studies). Before each NB study, the dietary intakes prior to the study were assessed in diaries and interviews. During a few days preceding the NB periods and during the NB periods each patient received an individualized diet composed so as to resemble the patients' spontaneously chosen diet regarding DPI and dietary energy intake (DEI). Total nitrogen, protein, urea and creatinine were analyzed in the dialysate and urine collected daily. Total nitrogen was also analyzed in the feces, collected over the whole NB period. Total nitrogen appearance (TNA), non-protein nitrogen appearance (NPNA) and urea nitrogen appearance (UNA) were calculated by correcting total nitrogen output, non-protein nitrogen output, that is, TNA minus the total protein losses (PL) and urea nitrogen output for changes in total body urea nitrogen. Glucose was determined in the collected dialysate and the daily glucose absorption was calculated. DPI varied between 0.62 and 2.09 g/kg/day, DEI between 21 and 42 kcal/kg/day and the peritoneal energy (glucose) intake (PEI) between 4 and 13 kcal/kg/day. DPI (but not DEI) correlated with Kt/Vurea and Kt/VCr and with total and renal clearances for urea and creatinine. NB (not corrected for “unmeasured” nitrogen losses) was positive in most studies, and it correlated with DPI and the total energy intake (TEI) in the early studies, but only with TEI in the late studies. DPI correlated with TNA, NPNA, UNA, non-protein-non-urea nitrogen loss and fecal nitrogen loss. UNA was highly correlated with TNA and NPNA (r = 0.95). We used data from 33 NB studies in CAPD patients (our present data combined with data from the literature) to calculate regression equations describing the relationship between TNA and NPNA, respectively, and UNA. Equations were derived by which the protein equivalent of TNA (PNA), that is, 6.25 TNA, and the protein equivalent of NPNA (PNPNA), that is, 6.25 NPNA, may be calculated from UNA which is directly measured. In stable CAPD patients, who are not strongly catabolic or anabolic, PNA may be used to estimate DPI and PNPNA may be used to estimate the net protein intake (DPI – PL)

The role of marketing in new ventures: How marketing activities should be organized in firms’ infancy

Although marketing activities are vital for new ventures (NVs) to ensure growth and survival, previous research is silent on how to organize them in firms’ infancy. The entrepreneurship literature focuses on which marketing activities to perform in NVs but not on how to organize these activities, whereas the marketing literature concentrates on how to organize marketing activities in established firms but not in NVs, which face specific opportunities and challenges in their early stage of development. This article aims to tackle this research gap by examining marketing’s role within NVs’ organization. Drawing on in-depth interviews with managers, we identify two key organizational dimensions: marketing’s dispersion (related to the proliferation and, thus, wide anchoring of marketing responsibilities) and marketing’s structuration (related to the manifestation and, thus, deep anchoring of marketing responsibilities). Through a field survey and archival data, we show that marketing’s dispersion enhances NV profitability, while marketing’s structuration decreases it, and that with increasing marketing influence (i.e., power of marketing actors) in NVs and NV maturity (i.e., age and size), this diametrical pattern of effects becomes less pronounced. Overall, the findings provide novel theoretical and practical insights into the organizational design of marketing in firms’ infancy.© The Author(s) 2023. This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made. The images or other third party material in this article are included in the article's Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article's Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit http://creativecommons.org/licenses/by/4.0/.fi=vertaisarvioitu|en=peerReviewed

Coupling hydrodynamics with comoving frame radiative transfer: II. Stellar wind stratification in the high-mass X-ray binary Vela X-1

CONTEXT: Vela X-1, a prototypical high mass X-ray binary (HMXB), hosts a neutron star (NS) in a close orbit around an early-B supergiant donor star. Accretion of the donor star's wind onto the NS powers its strong X-ray luminosity. To understand the physics of HMXBs, detailed knowledge about the donor star winds is required. AIMS: To gain a realistic picture of the donor star in Vela X-1, we constructed a hydrodynamically consistent atmosphere model describing the wind stratification while properly reproducing the observed donor spectrum. To investigate how X-ray illumination affects the stellar wind, we calculated additional models for different X-ray luminosity regimes. METHODS: We use the recently updated version of the PoWR code to consistently solve the hydrodynamic equation together with the statistical equations and the radiative transfer. RESULTS: The wind flow in Vela X-1 is driven by ions from various elements with Fe III and S III leading in the outer wind. The model-predicted mass-loss rate is in line with earlier empirical studies. The mass-loss rate is almost unaffected by the presence of the accreting NS in the wind. The terminal wind velocity is confirmed at $v_\infty \approx 600$ km/s. On the other hand, the wind velocity in the inner region where the NS is located is only $\approx 100$ km/s, which is not expected on the basis of a standard $\beta$-velocity law. In models with an enhanced level of X-rays, the velocity field in the outer wind can be altered. If the X-ray flux is too high, the acceleration breaks down because the ionization increases. CONCLUSIONS: Accounting for radiation hydrodynamics, our Vela X-1 donor atmosphere model reveals a low wind speed at the NS location, and it provides quantitative information on wind driving in this important HMXB.Comment: 19 pages, 10 figures, accepted for publication in Astronomy & Astrophysic

Atrial Natriuretic Peptide Protects against Histamine-Induced Endothelial Barrier Dysfunction in Vivo

Endothelial barrier dysfunction is a hallmark of many severe pathologies, including sepsis or atherosclerosis. The cardiovascular hormone atrial natriuretic peptide (ANP) has increasingly been suggested to counteract endothelial leakage. Surprisingly, the precise in vivo relevance of these observations has never been evaluated. Thus, we aimed to clarify this issue and, moreover, to identify the permeability-controlling subcellular systems that are targeted by ANP. Histamine was used as important pro-inflammatory, permeability-increasing stimulus. Measurements of fluorescein isothiocyanate (FITC)-dextran extravasation from venules of the mouse cremaster muscle and rat hematocrit values were performed to judge changes of endothelial permeability in vivo. It is noteworthy that ANP strongly reduced the histamine-evoked endothelial barrier dysfunction in vivo. In vitro, ANP blocked the breakdown of transendothelial electrical resistance (TEER) induced by histamine. Moreover, as judged by immunocytochemistry and Western blot analysis, ANP inhibited changes of vascular endothelial (VE)-cadherin, β-catenin, and p120ctn morphology; VE-cadherin and myosin light chain 2 (MLC2) phosphorylation; and F-actin stress fiber formation. These changes seem to be predominantly mediated by the natriuretic peptide receptor (NPR)-A, but not by NPR-C. In summary, we revealed ANP as a potent endothelial barrier protecting agent in vivo and identified adherens junctions and the contractile apparatus as subcellular systems targeted by ANP. Thus, our study highlights ANP as an interesting pharmacological compound opening new therapeutic options for preventing endothelial leakage

The accretion environment in Vela X-1 during a flaring period using XMM-Newton

We present analysis of 100 ks contiguous XMM-Newton data of the prototypical wind accretor Vela X-1. The observation covered eclipse egress between orbital phases 0.134 and 0.265, during which a giant flare took place, enabling us to study the spectral properties both outside and during the flare. This giant flare with a peak luminosity of $3.92^{+0.42}_{-0.09} \times 10^{37}$ erg s$^{-1}$ allows estimates of the physical parameters of the accreted structure with a mass of $\sim$ $10^{21}$ g. We have been able to model several contributions to the observed spectrum with a phenomenological model formed by three absorbed power laws plus three emission lines. After analysing the variations with orbital phase of the column density of each component, as well as those in the Fe and Ni fluorescence lines, we provide a physical interpretation for each spectral component. Meanwhile, the first two components are two aspects of the principal accretion component from the surface of the neutron star, and the third component seems to be the \textit{X-ray light echo} formed in the stellar wind of the companion.Comment: Accepted. Astronomy and Astrophysics, 201

An 8.56 keV Absorption Line in the Hyperluminous X-Ray Source in NGC 4045: Ultrafast Outflow or Cyclotron Line?

© 2022. The Author(s). Published by the American Astronomical Society. This work is licenced under the terms of the Creative Commons license. https://creativecommons.org/licenses/by/4.0/We report on the discovery of an absorption line at E=8.56−0.11+0.05 keV detected with a significance of >3.3σ in the NuSTAR and XMM-Newton spectra of a newly discovered hyperluminous X-ray source (L X > 1041 erg s−1) in the galaxy NGC 4045 at a distance of 32 Mpc. The source was first discovered serendipitously in a Swift/XRT observation of the galaxy, and Swift monitoring reveals a highly variable source changing by over an order of magnitude from maximum to minimum. The origin of the absorption line appears likely to be from highly ionized iron with a blueshift of 0.19c, indicating an ultrafast outflow. However, the large equivalent width of the line ( EW=−0.22−0.09+0.08 keV) paired with the lack of other absorption lines detected is difficult to reconcile with models. An alternative explanation is that the line is due to a cyclotron resonance scattering feature produced by the interaction of X-ray photons with the powerful magnetic field of a neutron star.Peer reviewe

Looking at A 0535+26 at low luminosities with NuSTAR

We report on two NuSTAR observations of the HMXB A 0535+26 taken toward the end of its normal 2015 outburst at very low $3-50$ keV luminosities of ${\sim}1.4\times10^{36}$ erg/s and ${\sim}5\times10^{35}$ erg/s which are complemented by 9 Swift observations. The data clearly confirm indications seen in earlier data that the source's spectral shape softens as it becomes fainter. The smooth, exponential rollover at high energies present in the first observation evolves to a much more abrupt steepening of the spectrum at $20-30$ keV. The continuum evolution can be well described with emission from a magnetized accretion column, modeled using the compmag model modified by an additional Gaussian emission component for the fainter observation. Between the two observations, the optical depth changes from $0.75\pm0.04$ to $0.56^{+0.01}_{-0.04}$, the electron temperature remains constant, and there is an indication that the column decreases in radius. Since the energy resolved pulse profiles remain virtually unchanged in shape between the two observations, the emission properties of the accretion column, however, reflect the same accretion regime. This conclusion is also confirmed by our result that the energy of the cyclotron resonant scattering feature (CRSF) at ${\sim}45$ keV is independent of the luminosity, implying that the magnetic field in the region in which the observed radiation is produced is the same in both observations. Finally, we also constrain the evolution of the continuum parameters with rotational phase of the neutron star. The width of the CRSF could only be constrained for the brighter observation. Based on Monte-Carlo simulations of CRSF formation in single accretion columns, its pulse phase dependence supports a simplified fan beam emission pattern. The evolution of the CRSF width is very similar to that of the CRSF depth, which is in disagreement with expectations.Comment: 14 pages, 11 figures, 3 tables, accepted for publication in A&

Self-rated quality of life and school performance in relation to helminth infections: case study from Yunnan, People's Republic of China

Background: Expert opinion-derived disability weights are widely employed for estimating the global burden of diseases and injuries. For chronic diseases such as soil-transmitted helminthiasis and schistosomiasis, it has been suggested that a patient-based quality of life (QoL) approach should be considered for a more accurate appraisal of disability weights. METHODS AND RESULTS: We carried out a cross-sectional survey and assessed the prevalence and intensity of soil-transmitted helminth infections as well as self-rated QoL indicators among 252 students attending grades 5-8 in two schools (Bulangshan and Pu'er) in Yunnan province, People's Republic of China. Each student provided a single stool sample, which was subjected to duplicate Kato-Katz thick smear readings and a single FLOTAC examination for parasitological diagnosis. Prevalence rates for hookworm, Trichuris trichiura and Ascaris lumbricoides were high in Bulangshan (75.9%, 70.0% and 68.2%), while the respective prevalence rates in Pu'er were 66.9%, 56.5% and 9.2%. Students were interviewed with two standardised questionnaires, the EuroQoL-5 Dimensions (EQ-5D) and ShortForm-12 (SF-12) Health Survey. Impairment in any of the five dimensions of the EQ-5D was reported by 87% of the students. However, no clear differences could be observed between individuals with and those without helminth infections, and there were discrepancies between the two schools. A multivariate logistic regression model revealed no differences between students with varying infection status in the domains of the SF-12 (odds ratio close to 1.0). Somewhat more pronounced, yet not statistically significant differences were observed when end-of-school-term marks were compared with students' helminth infection status: infected individuals had lower marks in Chinese, English and mathematics, but not in sports, compared to their helminth-free counterparts. CONCLUSIONS: Our results point to unresolved issues and challenges regarding the cultural appropriateness of the widely used standard QoL questionnaires. Hence, new research is needed to further develop these instruments and to validate them in connection with chronic parasitic disease