92 research outputs found
Electromagnetic Polarizabilities and Charge Radii of the Nucleons in the Diquark-model
The diquark model is used to calculate the electromagnetic polarizabilities
and charge radii of the nucleons for three different potentials. Making the
scalar diquark lower in mass introduces a mixing angle between the
and states ,which allows an
improvement in value of all 6 properties. Generalizing the Gamov-Teller matrix
and the magnetic moment operator to the diquark model gives constraints on this
mixing. We obtain for the Richardson potential
Additional pion cloud contributions could
improve on all six results.Comment: 15 Pages, Latex, Figs on request, to be published Phys.Lett.B. Minor
errors corrected and eqn 5,6,8,9 correcte
Der Einfluss der LÀnge von BeobachtungszeitrÀumen auf die Identifizierung von Subgruppen in Online Communities
Die Verbreitung von Social Media und damit verbunden die entstehenden und wachsenden Communities im Internet fĂŒhren zu einer Zunahme von auswertbaren, digitalen Spuren, die hĂ€ufig öffentlich zugĂ€nglich sind. Diese lassen sich durch verschiedene analytische Verfahren wie z.B. die Methode der Sozialen Netzwerkanalyse [1] auswerten. Insbesondere AnsĂ€tze fĂŒr âCommunity Detectionâ erfreuen sich besonderer Beliebtheit, wodurch sich unter anderem innovative Untergemeinschaften und Subgruppen beispielsweise in groĂen âOpen Sourceâ-Projekten identifizieren lassen [2]. Im Rahmen dieser Anwendungen ergeben sich neue methodische und grundlegende Fragen, darunter die nach der Rolle der von Zeit in solchen Analysen. WĂ€hrend die Darstellung dynamischer Effekte (z.B. durch Animationen) die Zeit als expliziten Parameter enthĂ€lt, geht die Wahl der Zeitintervalle fĂŒr die Aggregation von Daten, aus denen dann Netzwerke gewonnen werden, nur implizit in die PrĂ€missen des Verfahrens ein. Diese Effekte wurden im Gegensatz zur Analyse von Dynamik bisher kaum untersucht. Im Fall der Sozialen Netzwerkanalyse ist die ZielreprĂ€sentation selbst nicht mehr zeitbehaftet sondern sozusagen ein âstatischer Schnappschussâ, wodurch etwa zeitabhĂ€ngige Interaktionsmuster nicht erkannt werden können.
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Community detection for access-control decisions: Analysing the role of homophily and information diffusion in Online Social Networks
Access-Control Lists (ACLs) (a.k.a. âfriend listsâ) are one of the most important privacy features of Online Social Networks (OSNs) as they allow users to restrict the audience of their publications. Nevertheless, creating and maintaining custom ACLs can introduce a high cognitive burden on average OSNs users since it normally requires assessing the trustworthiness of a large number of contacts. In principle, community detection algorithms can be leveraged to support the generation of ACLs by mapping a set of examples (i.e. contacts labelled as âuntrustedâ) to the emerging communities inside the userâs ego-network. However, unlike usersâ access-control preferences, traditional community-detection algorithms do not take the homophily characteristics of such communities into account (i.e. attributes shared among members). Consequently, this strategy may lead to inaccurate ACL configurations and privacy breaches under certain homophily scenarios. This work investigates the use of community-detection algorithms for the automatic generation of ACLs in OSNs. Particularly, it analyses the performance of the aforementioned approach under different homophily conditions through a simulation model. Furthermore, since private information may reach the scope of untrusted recipients through the re-sharing affordances of OSNs, information diffusion processes are also modelled and taken explicitly into account. Altogether, the removal of gatekeeper nodes is further explored as a strategy to counteract unwanted data dissemination
Quantum Corrections to Baryon Properties in Chiral Soliton Models
We present a procedure to calculate 1-loop graphs in the soliton sector of
chiral Lagrangians and use it to calculate quantum corrections to certain
baryon observables in Skyrme-type models. Results generally show an improvement
over the values obtained in tree approximation except for the case of the axial
coupling g_A.Comment: Chapters on magnetic polarizabilities and e.m. properties of Delta
isobar added, 90 pages, Latex, 9 Postscript figure
CMV Late Phase-Induced mTOR Activation Is Essential for Efficient Virus Replication in Polarized Human Macrophages : Antiviral Effects of mTOR Inhibitors
Human cytomegalovirus (CMV) remains one of the
most important pathogens following solid-organ
transplantation. Mounting evidence indicates that
mammalian target of rapamycin (mTOR) inhibitors
may decrease the incidence of CMV infection in solid-
organ recipients. Here we aimed at elucidating the
molecular mechanisms of this effect by employing
a human CMV (HCMV) infection model in human
macrophages, since myeloid cells are the principal
in
vivo
targets of HCMV. We demonstrate a highly di-
vergent host cell permissiveness for HCMV with opti-
mal infection susceptibility in M2 but not M1 polarized
macrophages. Employing an ultrahigh purified HCMV
stock we observed rapamycin-independent viral entry
and induction of IFN-b transcripts, but no proinflam-
matory cytokines or mitogen-activated protein kinases
and mTOR activation early after infection. However,
in the late infection phase, sustained mTOR activa-
tion was observed in HCMV-infected cells and was
required for efficient viral protein synthesis including
the viral late phase proteins pUL-44 and pp65. Accord-
ingly, rapamycin strongly suppressed CMV replication
3 and 5 days postinfection in macrophages. In conclu-
sion, these data indicate that mTOR is essential for
virus replication during late phases of the viral cycle in
myeloid cells and might explain the potent anti-CMV
effects of mTOR inhibitors after organ transplantatio
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Tumoral PD-L1 expression defines a subgroup of poor-prognosis vulvar carcinomas with non-viral etiology
Vulvar cancer is rare but incidence rates are increasing due to an aging population and higher frequencies of young women being affected. In locally advanced, metastatic or recurrent disease prognosis is poor and new treatment modalities are needed. Immune checkpoint blockade of the PD-1/PD-L1 pathway is one of the most important advancements in cancer therapy in the last years. The clinical relevance of PD-L1 expression in vulvar cancer, however, has not been studied so far. We determined PD-L1 expression, numbers of CD3+ T cells, CD20+ B cells, CD68+ monocytes/macrophages, Foxp3+ regulatory T cells and CD163+ tumor-associated macrophages by immunohistochemistry in 103 patients. Correlation analysis with clinicopathological parameters was undertaken; the cause-specific outcome was modeled with competing risk analysis; multivariate Cox regression was used to determine independent predictors of survival. Membranous PD-L1 was expressed in a minority of tumors, defined by HPV-negativity. Its presence geographically correlated with immunocyte-rich regions of cancer islets and was an independent prognostic factor for poor outcome. Our data support the notion that vulvar cancer is an immunomodulatory tumor that harnesses the PD-1/PD-L1 pathway to induce tolerance. Accordingly, immunotherapeutic approaches might have the potential to improve outcome in patients with vulvar cancer and could complement conventional cancer treatment
A randomized, placebo-controlled, double-blind, prospective trial to evaluate the effect of vildagliptin in new-onset diabetes mellitus after kidney transplantation
<p>Abstract</p> <p>Background</p> <p>New-onset diabetes mellitus after transplantation (NODAT), a frequent and serious complication after transplantation, is associated with decreased graft and patient survival. Currently, it is diagnosed and treated primarily according to existing guidelines for type II diabetes. To date, only a few trials have studied antidiabetic drugs in patients with NODAT. Vildagliptin is a novel dipeptidyl peptidase-4 (DPP-4) inhibitor that improves pancreatic islet function by enhancing both α- and ÎČ-cell responsiveness to increased blood glucose. Experimental data show potential protective effects of DPP-4 inhibitors on islet function after exogenous stress stimuli including immunosuppressants. Therefore, the therapy of NODAT with this class of compounds seems attractive. At present, vildagliptin is used to treat type II diabetes as monotherapy or in combination with other antidiabetic drugs, since that it efficiently decreases glycated hemoglobin (HbA1c) values. Additionally, vildagliptin has been shown to be safe in patients with moderately impaired kidney function. This study will evaluate the safety and efficacy of vildagliptin monotherapy in renal transplant recipients with recently diagnosed NODAT.</p> <p>Methods/Design</p> <p>This study is a randomized, placebo-controlled, double-blind, prospective phase II trial. Using the results of routinely performed oral glucose tolerance tests (OGTT) in stable renal transplant patients at our center, we will recruit patients without a history of diabetes and a 2 h glucose value surpassing 200 mg/dl (11.1 mmol/l). They are randomized to receive either 50 mg vildagliptin or placebo once daily. A total of 32 patients with newly diagnosed NODAT will be included. The primary endpoint is the difference in the 2 h glucose value between baseline and the repeated OGTT performed 3 months after treatment start, compared between the vildagliptin- and the placebo-group. Secondary endpoints include changes in HbA1c and fasting plasma glucose (FPG). The safety of vildagliptin in renal transplant patients will be assessed by the number of symptomatic hypoglycemic episodes (glucose <72 mg/dl or 4 mmol/l), the number of adverse events, and possible medication-associated side-effects.</p> <p>Discussion</p> <p>NODAT is a severe complication after kidney transplantation. Few trials have assessed the safety and efficacy of antidiabetic drugs for these patients. The purpose of this study is to assess the safety and efficacy of vildagliptin in renal transplant patients with NODAT.</p> <p>Trial Registration</p> <p>ClinicalTrials.gov NCT00980356</p
Camostat Mesylate Versus Lopinavir/Ritonavir in Hospitalized Patients With COVID-19âResults From a Randomized, Controlled, Open Label, Platform Trial (ACOVACT)
Background: To date, no oral antiviral drug has proven to be beneficial in hospitalized patients with COVID-19.Methods: In this randomized, controlled, open-label, platform trial, we randomly assigned patients â„18Â years hospitalized with COVID-19 pneumonia to receive either camostat mesylate (CM) (considered standard-of-care) or lopinavir/ritonavir (LPV/RTV). The primary endpoint was time to sustained clinical improvement (â„48Â h) of at least one point on the 7-category WHO scale. Secondary endpoints included length of stay (LOS), need for mechanical ventilation (MV) or death, and 29-day mortality.Results: 201 patients were included in the study (101 CM and 100 LPV/RTV) between 20 April 2020 and 14 May 2021. Mean age was 58.7Â years, and 67% were male. The median time from symptom onset to randomization was 7Â days (IQR 5â9). Patients in the CM group had a significantly shorter time to sustained clinical improvement (HR = 0.67, 95%-CI 0.49â0.90; 9 vs. 11Â days, p = 0.008) and demonstrated less progression to MV or death [6/101 (5.9%) vs. 15/100 (15%), p = 0.036] and a shorter LOS (12 vs. 14Â days, p = 0.023). A statistically nonsignificant trend toward a lower 29-day mortality in the CM group than the LPV/RTV group [2/101 (2%) vs. 7/100 (7%), p = 0.089] was observed.Conclusion: In patients hospitalized for COVID-19, the use of CM was associated with shorter time to clinical improvement, reduced need for MV or death, and shorter LOS than the use of LPV/RTV. Furthermore, research is needed to confirm the efficacy of CM in larger placebo-controlled trials.Systematic Review Registration: [https://clinicaltrials.gov/ct2/show/NCT04351724, https://www.clinicaltrialsregister.eu/ctr-search/trial/2020-001302-30/AT], identifier [NCT04351724, EUDRACT-NR: 2020â001302-30]
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