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We investigate constraints on neutron star structure arising from the assumptions that neutron stars have crusts, that recent calculations of pure neutron matter limit the equation of state of ...neutron star matter near the nuclear saturation density, that the high-density equation of state is limited by causality and the largest high-accuracy neutron star mass measurement, and that general relativity is the correct theory of gravity. We explore the role of prior assumptions by considering two classes of equation of state models. In a first, the intermediate- and high-density behavior of the equation of state is parameterized by piecewise polytropes. In the second class, the high-density behavior of the equation of state is parameterized by piecewise continuous line segments. The smallest density at which high-density matter appears is varied in order to allow for strong phase transitions above the nuclear saturation density. We critically examine correlations among the pressure of matter, radii, maximum masses, the binding energy, the moment of inertia, and the tidal deformability, paying special attention to the sensitivity of these correlations to prior assumptions about the equation of state. It is possible to constrain the radii of
neutron stars to be larger than 10km, even without consideration of additional astrophysical observations, for example, those from photospheric radius expansion bursts or quiescent low-mass X-ray binaries. We are able to improve the accuracy of known correlations between the moment of inertia and compactness as well as the binding energy and compactness. We also demonstrate the existence of a correlation between the neutron star binding energy and the moment of inertia.
Neutrino fluxes from proto-neutron stars with and without quarks are studied. Observable differences become apparent after 10-20 s of evolution. Sufficiently massive stars containing negatively ...charged, strongly interacting, particles collapse to black holes during the first minute of evolution. Since the neutrino flux vanishes when a black hole forms, this is the most obvious signal that quarks (or other types of strange matter) have appeared. The metastability time scales for stars with quarks are intermediate between those containing hyperons and kaon condensates.
BACKGROUND
To evaluate the safety of ICSI with epididymal sperm, this study compared children born after ICSI treatment with epididymal sperm and children conceived after IVF and ICSI with ejaculated ...sperm. Additionally, the results of a multidisciplinary, multicentre follow-up of the children conceived with epididymal sperm at 2 years of age are described.
METHODS
This follow-up study included 378 children conceived after ICSI with epididymal sperm (percutaneous epididymal sperm aspiration: PESA group) and a control group of 1192 IVF and 1126 ICSI (with ejaculated sperm) children, all with a gestational age of 20 weeks or more. Questionnaires were sent at birth, 1 year and 4 years of age, collecting data on parental, pregnancy and child factors. A total of 148 PESA children were assessed at 2 years of age for motor performance, mental- and language development and compared with the Dutch norms.
RESULTS
PESA children showed no increased risks for stillbirths, total deaths and malformations. They also did not differ from IVF and ICSI children in gender rate, birthweight and gestational age. The mental Bayley score was higher (P < 0.05) for PESA singletons and parents reported fewer (P < 0.05) behavioural problems in the PESA group than the Dutch reference group. The scores for syntactic and lexical development for the PESA singletons were better (P < 0.05) than the Dutch standards.
CONCLUSIONS
ICSI with epididymal sperm does not lead to more stillbirths or congenital malformations in comparison to IVF and ICSI with ejaculated sperm and does not lead to poor development in comparison with the Dutch reference group.
An involvement of the transient receptor potential vanilloid (TRPV) 1 channel in the regulation of body temperature (T(b)) has not been established decisively. To provide decisive evidence for such ...an involvement and determine its mechanisms were the aims of the present study. We synthesized a new TRPV1 antagonist, AMG0347 (E)-N-(7-hydroxy-5,6,7,8-tetrahydronaphthalen-1-yl)-3-(2-(piperidin-1-yl)-6-(trifluoromethyl)pyridin-3-yl)acrylamide, and characterized it in vitro. We then found that this drug is the most potent TRPV1 antagonist known to increase T(b) of rats and mice and showed (by using knock-out mice) that the entire hyperthermic effect of AMG0347 is TRPV1 dependent. AMG0347-induced hyperthermia was brought about by one or both of the two major autonomic cold-defense effector mechanisms (tail-skin vasoconstriction and/or thermogenesis), but it did not involve warmth-seeking behavior. The magnitude of the hyperthermic response depended on neither T(b) nor tail-skin temperature at the time of AMG0347 administration, thus indicating that AMG0347-induced hyperthermia results from blockade of tonic TRPV1 activation by nonthermal factors. AMG0347 was no more effective in causing hyperthermia when administered into the brain (intracerebroventricularly) or spinal cord (intrathecally) than when given systemically (intravenously), which indicates a peripheral site of action. We then established that localized intra-abdominal desensitization of TRPV1 channels with intraperitoneal resiniferatoxin blocks the T(b) response to systemic AMG0347; the extent of desensitization was determined by using a comprehensive battery of functional tests. We conclude that tonic activation of TRPV1 channels in the abdominal viscera by yet unidentified nonthermal factors inhibits skin vasoconstriction and thermogenesis, thus having a suppressive effect on T(b).
The human spleen contracts in response to stress‐induced catecholamine secretion, resulting in a temporary rise in haemoglobin concentration (Hb). Recent findings highlighted enhanced splenic ...response to exercise at high altitude in Sherpa, possibly due to a blunted splenic response to hypoxia. To explore the potential blunted splenic contraction in Sherpas at high altitude, we examined changes in spleen volume during hyperoxic breathing, comparing acclimatized Sherpa with acclimatized individuals of lowland ancestry. Our study included 14 non‐Sherpa (7 female) residing at altitude for a mean continuous duration of 3 months and 46 Sherpa (24 female) with an average of 4 years altitude exposure. Participants underwent a hyperoxic breathing test at altitude (4300 m; barrometric pressure = ∼430 torr; PO2${P_{{{\mathrm{O}}_{\mathrm{2}}}$ = ∼90 torr). Throughout the test, we measured spleen volume using ultrasonography and monitored oxygen saturation (SpO2${S_{{\mathrm{p}}{{\mathrm{O}}_{\mathrm{2}}}$). During rest, Sherpa exhibited larger spleens (226 ± 70 mL) compared to non‐Sherpa (165 ± 34 mL; P < 0.001; effect size (ES) = 0.95, 95% CI: 0.3–1.6). In response to hyperoxia, non‐Sherpa demonstrated 22 ± 12% increase in spleen size (35 ± 17 mL, 95% CI: 20.7–48.9; P < 0.001; ES = 1.8, 95% CI: 0.93–2.66), while spleen size remained unchanged in Sherpa (−2 ± 13 mL, 95% CI: −2.4 to 7.3; P = 0.640; ES = 0.18, 95% CI: −0.10 to 0.47). Our findings suggest that Sherpa and non‐Sherpas of lowland ancestry exhibit distinct variations in spleen volume during hyperoxia at high altitude, potentially indicating two distinct splenic functions. In Sherpa, this phenomenon may signify a diminished splenic response to altitude‐related hypoxia at rest, potentially contributing to enhanced splenic contractions during physical stress. Conversely, non‐Sherpa experienced a transient increase in spleen size during hyperoxia, indicating an active tonic contraction, which may influence early altitude acclimatization in lowlanders by raising Hb.
What is the central question of this study?
Indigenous Sherpa exhibit greater spleen size and enhanced exercise‐induced contraction at high altitude compared to lowlanders: how does spleen size of Sherpa and lowlanders respond to hyperoxic breathing at high altitude?
What is the main finding and its importance?
Sherpa do not experience any changes in spleen size when subjected to hyperoxic breathing at high altitude, whereas lowlanders show a 20% increase in spleen size under similar conditions. This may represent adaptive traits in Sherpa, potentially enhancing the spleen's capacity for contractions during increased metabolic demands.
Intravenous gammaglobulin (i.v.IG) contains anti-idiotypic antibodies that are potent inhibitors of HLA-specific alloantibodies in vitro and in vivo. In addition, highly HLA-allosensitized patients ...awaiting transplantation can have HLA alloantibody levels reduced dramatically by i.v.IG infusions, and subsequent transplantation can be accomplished successfully with a crossmatch-negative, histoincompatible organ.
In this study, we investigated the possible use of i.v.IG to reduce donor-specific anti-HLA alloantibodies arising after transplantation and its efficacy in treating antibody-mediated allograft rejection (AR) episodes. We present data on 10 patients with severe allograft rejection, four of whom developed AR episodes associated with high levels of donor-specific anti-HLA alloantibodies.
Most patients showed rapid improvements in AR episodes, with resolution noted within 2-5 days after i.v.IG infusions in all patients. i.v.IG treatment also rapidly reduced donor-specific anti-HLA alloantibody levels after i.v.IG infusion. All AR episodes were reversed. Freedom from recurrent rejection episodes was seen in 9 of 10 patients, some with up to 5 years of follow-up. Results of protein G column fractionation studies from two patients suggest that the potential mechanism by which i.v.IG induces in vivo suppression is a sequence of events leading from initial inhibition due to passive transfer of IgG to eventual active induction of an IgM or IgG blocking antibody in the recipient.
I.v.IG appears to be an effective therapy to control posttransplant AR episodes in heart and kidney transplant recipients, including patients who have had no success with conventional therapies. Vascular rejection episodes associated with development of donor-specific cytotoxic antibodies appears to be particularly responsive to i.v.IG therapy.
Pulmonary metastasis (M1-PUL) as first site of dissemination in pancreatic ductal adenocarcinoma (PDAC) is a rare event and may define a distinct biological subgroup.
Arbeitsgemeinschaft ...Internistische Onkologie-Young Medical Oncologists-Pankreas-0515 study (AIO-YMO-PAK-0515) was a retrospective German multicenter study investigating clinical and molecular characteristics of M1-PUL PDAC patients; 115 M1-PUL PDAC patients from 7 participating centers were included. Clinical characteristics and potential prognostic factors were defined within the M1-PUL cohort. Archival tumor samples were analyzed for Her2/neu, HNF1A and KRT81 expression. Additionally, messenger RNA (mRNA) expression analysis (using a 770-gene immune profiling panel) was carried out in the M1-PUL and in a control cohort (M1-ANY).
Median overall survival in the entire M1-PUL cohort was 20 months; the most favorable prognosis (median survival: 28 months) was observed in the subgroup of 66 PDAC patients with metachronous lung metastases after previous curative-intent surgery. The number of metastatic lesions, uni- or bilateral lung involvement as well as metastasectomy were identified as potential prognostic factors. Her2/neu expression and PDAC subtyping (by HNF1A and KRT81) did not differ between the M1-PUL and the M1-ANY cohort. mRNA expression analysis revealed significant differentially expressed genes between both cohorts: CD63 and LAMP1 were among the top 20 differentially expressed genes and were identified as potential mediators of organotropism and favorable survival outcome of M1-PUL patients.
M1-PUL represents a clinically favorable cohort in PDAC patients. Site of relapse might already be predetermined at the time of surgery and could potentially be predicted by gene expression profiling.
•The retrospective multicenter AIO-YMO-PAK-0515 study defines M1-PUL as a clinically favorable subgroup in PDAC.•The number of metastatic lesions, bilateral lung involvement and surgical metastasectomy may serve as prognostic factors.•Immune-related gene expression differs between patients with isolated pulmonary relapse versus other sites of relapse.
Strange star surface: a crust with nuggets Jaikumar, Prashanth; Reddy, Sanjay; Steiner, Andrew W
Physical review letters,
02/2006, Letnik:
96, Številka:
4
Journal Article
Recenzirano
Odprti dostop
We reexamine the surface composition of strange stars. Strange quark stars are hypothetical compact stars which could exist if strange quark matter was absolutely stable. It is widely accepted that ...they are characterized by an enormous density gradient (10(26) g/cm4) and large electric fields at the surface. By investigating the possibility of realizing a heterogeneous crust, comprised of nuggets of strange quark matter embedded in an uniform electron background, we find that the strange star surface has a much reduced density gradient and negligible electric field. We comment on how our findings will impact various proposed observable signatures for strange stars.
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