753 research outputs found
Domain walls at the spin density wave endpoint of the organic superconductor (TMTSF)2PF6 under pressure
We report the first comprehensive investigation of the organic superconductor
(TMTSF)2PF6 in the vicinity of the endpoint of the spin density wave - metal
phase transition where phase coexistence occurs. At low temperature, the
transition of metallic domains towards superconductivity is used to reveal the
various textures. In particular, we demonstrate experimentally the existence of
1D and 2D metallic domains with a cross-over from a filamentary
superconductivity mostly along the c?-axis to a 2D superconductivity in the
b?c-plane perpendicular to the most conducting direction. The formation of
these domain walls may be related to the proposal of a soliton phase in the
vicinity of the critical pressure of the (TMTSF)2PF6 phase diagram.Comment: 5 page
Lung protection in cardio-pulmonary bypass
Since the invention of the heart-lung machine paediatric cardiac surgery
developed rapidly. For correction of complex cardiac malformations the
application of a cardio-pulmonary bypass (CPB) has become indispensable but
possible negative effects of this technique should not be neglected.
Especially, both bypassed organs i.e. heart and lung are not perfused during
the procedure and therefore are threatened by ischemia and reperfusion injury.
Additionally, CPB was developed with a non-pulsatile flow but there are
clinical observations that pulsatile flow might be superior with improved
patient outcomes. Thus, the aim of our study was to evaluate the effect of CPB
on lung structure and to assess whether different flow modalities (pulsatile
vs. non-pulsatile flow) or application of the antibiotic minocycline might be
advantageous. Thirty five piglets of four weeks age were examined and divided
into five experimental groups: control (no CPB) without or with minocycline,
CPB (non-pulsatile flow) without or with minocycline and CPB with pulsatile
flow. CPB was performed for 90 min followed by a 120 min reperfusion and
recovery phase. Thereafter, adenosine triphosphate-content of lung biopsies
and histology was carried out. We found that CPB was associated with a
significant thickening of alveolar wall accompanied by an infiltration of
neutrophil leucocytes. Moreover, markers for hypoxia, apoptosis, nitrosative
stress, inflammation and DNA damage were significantly elevated after CPB.
These cellular damages could be partially inhibited by minocycline or
pulsatile flow. Both, minocycline and pulsatile flow attenuate lung damage
after CPB
Upper critical field divergence induced by mesoscopic phase separation in the organic superconductor (TMTSF)2ReO4
Due to the competition of two anion orders, (TMTSF)2ReO4, presents a phase
coexistence between semiconducting and metallic (superconducting) regions
(filaments or droplets) in a wide range of pressure. In this regime, the
superconducting upper critical field for H parallel to both c* and b' axes
present a linear part at low fields followed by a divergence above a cross-over
field. This cross-over corresponds to the 3D-2D decoupling transition expected
in filamentary or granular superconductors. The sharpness of the transition
also demonstrates that all filaments are of similar sizes and self organize in
a very ordered way. The distance between the filaments and their cross-section
are estimated.Comment: 4 pages, 4 figure
Ab initio studies of electronic structure of defects in PbTe
Understanding the detailed electronic structure of deep defect states in
narrow band-gap semiconductors has been a challenging problem. Recently,
self-consistent ab initio calculations within density functional theory (DFT)
using supercell models have been successful in tackling this problem. In this
paper, we carry out such calculations in PbTe, a well-known narrow band-gap
semiconductor, for a large class of defects: cationic and anionic
substitutional impurities of different valence, and cationic and anionic
vacancies. For the cationic defects, we study a series of compounds
RPb2n-1Te2n, where R is vacancy or monovalent, divalent, or trivalent atom; for
the anionic defects, we study compounds MPb2nTe2n-1, where M is vacancy, S, Se
or I. We find that the density of states (DOS) near the top of the valence band
and the bottom of the conduction band get significantly modified for most of
these defects. This suggests that the transport properties of PbTe in the
presence of impurities can not be interpreted by simple carrier doping
concepts, confirming such ideas developed from qualitative and
semi-quantitative arguments
Insertion Detection System Employing Neural Network MLP and Detection Trees Using Different Techniques
by addressing intruder attacks, network security experts work to maintain services available at all times. The Intrusion Detection System (IDS) is one of the available mechanisms for detecting and classifying any abnormal behavior. As a result, the IDS must always be up to date with the most recent intruder attack signatures to maintain the confidentiality, integrity, and availability of the services. This paper shows how the NSL-KDD dataset may be used to test and evaluate various Machine Learning techniques. It focuses mostly on the NLS-KDD pre-processing step to create an acceptable and balanced experimental data set to improve accuracy and minimize false positives. For this study, the approaches J48 and MLP were employed. The Decision Trees classifier has been demonstrated to have the highest accuracy rate for detecting and categorizing all NSL-KDD dataset attacks
Adverse drug events associated with vitamin K antagonists: factors of therapeutic imbalance
Nancy El-Helou, Amal Al-Hajje, Rola Ajrouche, Sanaa Awada, Samar Rachidi, Salam Zein, Pascale SalamehClinical and Epidemiological Research Laboratory, Faculty of Pharmacy, Lebanese University, Beirut, LebanonBackground: Adverse drug events (ADE) occur frequently during treatment with vitamin K antagonists (AVK) and contribute to increase hemorrhagic risks.Methods: A retrospective study was conducted over a period of 2 years. Patients treated with AVK and admitted to the emergency room of a tertiary care hospital in Beirut were included. The aim of the study was to identify ADE characterized by a high international normalized ratio (INR) and to determine the predictive factors responsible for these events. Statistical analysis was performed with the SPSS statistical package.Results: We included 148 patients. Sixty-seven patients (47.3%) with an INR above the therapeutic range were identified as cases. The control group consisted of 81 patients (54.7%) with an INR within the therapeutic range. Hemorrhagic complications were observed in 53.7% of cases versus 6.2% of controls (P < 0.0001). No significant difference was noticed between cases and controls regarding the indication and the dose of AVK. Patients aged over 75 years were more likely to present an INR above the therapeutic range (58.2%, P = 0.049). Recent infection was present in 40.3% of cases versus 6.2% of controls (P < 0.0001) and hypoalbuminemia in 37.3% of cases versus 6.1% of controls (P < 0.0001). Treatment with antibiotics, amiodarone, and anti-inflammatory drugs were also factors of imbalance (P < 0.0001).Conclusion: Many factors may be associated with ADE related to AVK. Monitoring of INR and its stabilization in the therapeutic range are important for preventing these events.Keywords: adverse drug events, vitamin K antagonists, bleeding risks, therapeutic imbalanc
Characterization of uncertainties in atmospheric trace gas inversions using hierarchical Bayesian methods
We present a hierarchical Bayesian method for atmospheric trace gas
inversions. This method is used to estimate emissions of trace gases as well
as "hyper-parameters" that characterize the probability density functions
(PDFs) of the a priori emissions and model-measurement covariances. By
exploring the space of "uncertainties in uncertainties", we show that the
hierarchical method results in a more complete estimation of emissions and
their uncertainties than traditional Bayesian inversions, which rely heavily
on expert judgment. We present an analysis that shows the effect of
including hyper-parameters, which are themselves informed by the data, and
show that this method can serve to reduce the effect of errors in assumptions
made about the a priori emissions and model-measurement uncertainties. We
then apply this method to the estimation of sulfur hexafluoride (SF6)
emissions over 2012 for the regions surrounding four Advanced Global
Atmospheric Gases Experiment (AGAGE) stations. We find that improper
accounting of model representation uncertainties, in particular, can lead to
the derivation of emissions and associated uncertainties that are unrealistic
and show that those derived using the hierarchical method are likely to be
more representative of the true uncertainties in the system. We demonstrate
through this SF6 case study that this method is less sensitive to
outliers in the data and to subjective assumptions about a priori emissions
and model-measurement uncertainties than traditional methods
Disruption of the Hippocampal and Hypothalamic Blood-Brain Barrier in a Diet-Induced Obese Model of Type II Diabetes: Prevention and Treatment by the Mitochondrial Carbonic Anhydrase Inhibitor, Topiramate
Background: Type II diabetes is a vascular risk factor for cognitive impairment and increased risk of dementia. Disruption of the blood–retinal barrier (BRB) and blood–brain barrier (BBB) are hallmarks of subsequent retinal edema and central nervous system dysfunction. However, the mechanisms by which diet or metabolic syndrome induces dysfunction are not understood. A proposed mechanism is an increase in reactive oxygen species (ROS) and oxidative stress. Inhibition of mitochondrial carbonic anhydrase (mCA) decreases ROS and oxidative stress. In this study, topiramate, a mCA inhibitor, was examined for its ability to protect the BRB and BBB in diet-induced obese type II diabetic mice.
Methods: BBB and BRB permeability were assessed using 14C-sucrose and 99mTc-albumin in CD-1 mice fed a low-fat (control) or a high-fat diet. Topiramate administration was compared to saline controls in both preventative and efficacy arms examining BRB and BBB disruption. Body weight and blood glucose were measured weekly and body composition was assessed using EchoMRI. Metabolic activity was measured using a comprehensive laboratory animal monitoring system. Brain tissues collected from the mice were assessed for changes in oxidative stress and tight junction proteins.
Results: High-fat feeding caused increased entry of 14C-sucrose and 99mTc-albumin into the brains of diet-induced obese type II diabetic mice. Increased permeability to 14C-sucrose was observed in the hypothalamus and hippocampus, and attenuated by topiramate treatment, while increased permeability to 99mTc-albumin occurred in the whole brain and was also attenuated by topiramate. Treatment with topiramate decreased measures of oxidative stress and increased expression of the tight junction proteins ZO-1 and claudin-12. In the retina, we observed increased entry of 99mTc-albumin simultaneously with increased entry into the whole brain during the preventative arm. This occurred prior to increased entry to the retina for 14C-sucrose which occurred during the efficacy arm. Treatment with topiramate had no effect on the retina.
Conclusions: Blood–brain barrier and blood–retinal barrier dysfunction were examined in a mouse model of diet-induced obese type II diabetes. These studies demonstrate that there are spatial and temporal differences in 14C-sucrose and 99mTc-albumin permeability in the brain and retina of diet-induced obese type II diabetic mice. Topiramate, a mitochondrial carbonic anhydrase inhibitor, is efficacious at both preventing and treating BBB disruption in this diet-induced obese type II diabetic mouse model
Pharmacy education and practice in 13 middle eastern countries
The Arab world has influenced the art and science of pharmacy for centuries. Pharmacy education and practice is continuing to evolve in the Arabic-speaking traditional Middle East countries, although relatively little information has been published in the English press. Our goal was to providea high-level synopsis of conditions in this region.
We selected 13 countries for review. Information was obtained by reviewing the available published literature and individual university and program web sites, as well as contacting with program or country representatives. Seventy-eight active pharmacy schools in 12 countries were identified. At least 14,000 students (over 75% from Egypt) are admitted into baccalaureate degree programs every year. The 5-year baccalaureate degree remains the first professional degree to practice.
While changes in pharmacy education have been relatively rapid over the past decade, the advancement of pharmacy practice, particularly in the private sector, appears to be slower. Hospital pharmacists often possess an advanced degree and tend to have a higher level of practice compared to that of community pharmacists. Despite the adversities that face academics and practitioners alike, there is a strong desire to advance the science and practice of pharmacy in the Middle East
- …