151 research outputs found
Statistical modeling of ground motion relations for seismic hazard analysis
We introduce a new approach for ground motion relations (GMR) in the
probabilistic seismic hazard analysis (PSHA), being influenced by the extreme
value theory of mathematical statistics. Therein, we understand a GMR as a
random function. We derive mathematically the principle of area-equivalence;
wherein two alternative GMRs have an equivalent influence on the hazard if
these GMRs have equivalent area functions. This includes local biases. An
interpretation of the difference between these GMRs (an actual and a modeled
one) as a random component leads to a general overestimation of residual
variance and hazard. Beside this, we discuss important aspects of classical
approaches and discover discrepancies with the state of the art of stochastics
and statistics (model selection and significance, test of distribution
assumptions, extreme value statistics). We criticize especially the assumption
of logarithmic normally distributed residuals of maxima like the peak ground
acceleration (PGA). The natural distribution of its individual random component
(equivalent to exp(epsilon_0) of Joyner and Boore 1993) is the generalized
extreme value. We show by numerical researches that the actual distribution can
be hidden and a wrong distribution assumption can influence the PSHA negatively
as the negligence of area equivalence does. Finally, we suggest an estimation
concept for GMRs of PSHA with a regression-free variance estimation of the
individual random component. We demonstrate the advantages of event-specific
GMRs by analyzing data sets from the PEER strong motion database and estimate
event-specific GMRs. Therein, the majority of the best models base on an
anisotropic point source approach. The residual variance of logarithmized PGA
is significantly smaller than in previous models. We validate the estimations
for the event with the largest sample by empirical area functions. etc
TRAF4 is a novel phosphoinositide-binding protein modulating tight junctions and favoring cell migration
Tumor necrosis factor (TNF) receptor-associated factor 4 (TRAF4) is frequently overexpressed in carcinomas, suggesting a specific role in cancer. Although TRAF4 protein is predominantly found at tight junctions (TJs) in normal mammary epithelial cells (MECs), it accumulates in the cytoplasm of malignant MECs. How TRAF4 is recruited and functions at TJs is unclear. Here we show that TRAF4 possesses a novel phosphoinositide (PIP)-binding domain crucial for its recruitment to TJs. Of interest, this property is shared by the other members of the TRAF protein family. Indeed, the TRAF domain of all TRAF proteins (TRAF1 to TRAF6) is a bona fide PIP-binding domain. Molecular and structural analyses revealed that the TRAF domain of TRAF4 exists as a trimer that binds up to three lipids using basic residues exposed at its surface. Cellular studies indicated that TRAF4 acts as a negative regulator of TJ and increases cell migration. These functions are dependent from its ability to interact with PIPs. Our results suggest that TRAF4 overexpression might contribute to breast cancer progression by destabilizing TJs and favoring cell migration
A large topographic feature on the surface of the trans-Neptunian object (307261) 2002 MS measured from stellar occultations
This work aims at constraining the size, shape, and geometric albedo of the
dwarf planet candidate 2002 MS4 through the analysis of nine stellar
occultation events. Using multichord detection, we also studied the object's
topography by analyzing the obtained limb and the residuals between observed
chords and the best-fitted ellipse. We predicted and organized the
observational campaigns of nine stellar occultations by 2002 MS4 between 2019
and 2022, resulting in two single-chord events, four double-chord detections,
and three events with three to up to sixty-one positive chords. Using 13
selected chords from the 8 August 2020 event, we determined the global
elliptical limb of 2002 MS4. The best-fitted ellipse, combined with the
object's rotational information from the literature, constrains the object's
size, shape, and albedo. Additionally, we developed a new method to
characterize topography features on the object's limb. The global limb has a
semi-major axis of 412 10 km, a semi-minor axis of 385 17 km, and
the position angle of the minor axis is 121 16. From
this instantaneous limb, we obtained 2002 MS4's geometric albedo and the
projected area-equivalent diameter. Significant deviations from the fitted
ellipse in the northernmost limb are detected from multiple sites highlighting
three distinct topographic features: one 11 km depth depression followed by a
25 km height elevation next to a crater-like depression with an
extension of 322 39 km and 45.1 1.5 km deep. Our results present an
object that is 138 km smaller in diameter than derived from thermal
data, possibly indicating the presence of a so-far unknown satellite. However,
within the error bars, the geometric albedo in the V-band agrees with the
results published in the literature, even with the radiometric-derived albedo
Global overview of the management of acute cholecystitis during the COVID-19 pandemic (CHOLECOVID study)
Background: This study provides a global overview of the management of patients with acute cholecystitis during the initial phase of the COVID-19 pandemic. Methods: CHOLECOVID is an international, multicentre, observational comparative study of patients admitted to hospital with acute cholecystitis during the COVID-19 pandemic. Data on management were collected for a 2-month study interval coincident with the WHO declaration of the SARS-CoV-2 pandemic and compared with an equivalent pre-pandemic time interval. Mediation analysis examined the influence of SARS-COV-2 infection on 30-day mortality. Results: This study collected data on 9783 patients with acute cholecystitis admitted to 247 hospitals across the world. The pandemic was associated with reduced availability of surgical workforce and operating facilities globally, a significant shift to worse severity of disease, and increased use of conservative management. There was a reduction (both absolute and proportionate) in the number of patients undergoing cholecystectomy from 3095 patients (56.2 per cent) pre-pandemic to 1998 patients (46.2 per cent) during the pandemic but there was no difference in 30-day all-cause mortality after cholecystectomy comparing the pre-pandemic interval with the pandemic (13 patients (0.4 per cent) pre-pandemic to 13 patients (0.6 per cent) pandemic; P = 0.355). In mediation analysis, an admission with acute cholecystitis during the pandemic was associated with a non-significant increased risk of death (OR 1.29, 95 per cent c.i. 0.93 to 1.79, P = 0.121). Conclusion: CHOLECOVID provides a unique overview of the treatment of patients with cholecystitis across the globe during the first months of the SARS-CoV-2 pandemic. The study highlights the need for system resilience in retention of elective surgical activity. Cholecystectomy was associated with a low risk of mortality and deferral of treatment results in an increase in avoidable morbidity that represents the non-COVID cost of this pandemic
The effects of gender and menopause on serum lidocaine levels in smokers
it has been established that human cytochrome P450 (CYP) enzymatic activity is affected by gender, or by hormonal factors such as the menopause in women. Gender differences have a more pronounced effect on cytochrome (CYP) 3A4 isoenzyme activity, whereas cytochrome (CYP) 1A2 isoenzyme activity is mainly induced by chronic smoking. Lidocaine is frequently used in the treatment of hemodynamic changes following laryngoscopy and tracheal intubation during general anesthesia, and is metabolized by CYP3A4 and CYP1A2 isoenzymes in the liver
Clinical overview of children with mucopolysaccharidosis type III A and effect of Risperidone treatment on children and their mothers psychological status
PubMed ID: 19217229Mucopolysaccharidosis IIIA (MPS IIIA) is a lysosomal storage disorder characterized by progressive mental deterioration and severe behavioral problems. We conducted an open-label, crossover study of the efficacy and safety of Risperidone on behavioral disorder in children with MPS IIIA. A total of 12 patients (5.5 ± 2.2 years) with enzymatic diagnosis of MPS IIIA were randomly assigned to receive Risperidone (0.125-2 mg/d) for 6 months. The hyperactivity and disruptive behavior level of children before and after treatment was evaluated regarding the scores from Turgay DSM IV Based Child and Adolescent Behavior Disorders Screening and Rating Scale (T-DSM-IV-S). Clinic Global Impression Scale - Severity (CGIS-S) was used for all cases for determining the psychiatric disorder severity. The anxiety and depression levels of mothers before and after treatment were evaluated using Hamilton Anxiety Scale (HAM-A) and Beck Depression Inventory (BDI). The adverse effects were evaluated by monitoring weight, serum prolactin, glucose and lipid levels. The response to the treatment was measured by decrease in values of CGI-S (from 6 ± 1.12 to 2.91 ± 0.66, p = 0.001). According to T-DSM-IV-S scores the best improvement was observed in hyperactivity scores (16.25 ± 8.57/11.58 ± 7.26, p = 0.001), followed by opposition/defiance (6.66 ± 5.92/5.08 ± 4.88, p = 0.032), and conduct disorder scores (1.00 ± 1.85/0.41 ± .99, p = 0.67). No clinically relevant elevations in weight and serum prolactin, glucose or lipid levels have been documented (p > 0.05). There was a significant decrease in anxiety and depression scores of mothers (HAM-A: 20.33 ± 8.28/17.91 ± 6.89, BDI: 23.58 ± 7.14/20.5 ± 5.93, p < 0.001). To our knowledge, research on the pharmacological treatment of MPS IIIA with Risperidone has not been reported. According to our data, Risperidone appeared to be safe and effective in MPS IIIA patients. © 2008 Elsevier B.V. All rights reserved
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