A randomized trial to assess the impact of an antithrombotic decision aid in patients with nonvalvular atrial fibrillation: the DAAFI trial protocol [ISRCTN14429643]

BACKGROUND: Decision aids are often advocated as a means to assist patient and health care provider decision making when faced with complicated treatment or screening decisions. Despite an exponential growth in the availability of decision aids in recent years, their impact on long-term treatment decisions and patient adherence is uncertain due to a paucity of rigorous studies. The choice of antithrombotic therapy for nonvalvular atrial fibrillation (NVAF) is one condition for which a trade-off exists between the potential risks and benefits of competing therapies, and the need to involve patients in decision making has been clearly identified. This study will evaluate whether an evidence-based patient decision aid for patients with NVAF can improve the appropriateness of antithrombotic therapy use by patients and their family physicians. DESIGN: A multi-center, two-armed cluster randomized trial based in community family practices in which patients with NVAF will be randomized to decision aid or usual care. Patients will receive one of four decision aids depending on their baseline stroke risk. The primary outcome is the provision of "appropriate antithrombotic therapy" at 3 months to study participants (appropriateness defined as per the 2001 American College of Chest Physicians recommendations for NVAF). In addition, the impact of this decision aid on patient knowledge, decisional conflict, well-being, and adherence will be assessed after 3 months, 6 months, and 12 months

Generation of photovoltage in graphene on a femtosecond time scale through efficient carrier heating

Graphene is a promising material for ultrafast and broadband photodetection. Earlier studies addressed the general operation of graphene-based photo-thermoelectric devices, and the switching speed, which is limited by the charge carrier cooling time, on the order of picoseconds. However, the generation of the photovoltage could occur at a much faster time scale, as it is associated with the carrier heating time. Here, we measure the photovoltage generation time and find it to be faster than 50 femtoseconds. As a proof-of-principle application of this ultrafast photodetector, we use graphene to directly measure, electrically, the pulse duration of a sub-50 femtosecond laser pulse. The observation that carrier heating is ultrafast suggests that energy from absorbed photons can be efficiently transferred to carrier heat. To study this, we examine the spectral response and find a constant spectral responsivity between 500 and 1500 nm. This is consistent with efficient electron heating. These results are promising for ultrafast femtosecond and broadband photodetector applications.Comment: 6 pages, 4 figure

Preparation of stable magnetic nanofluids containing Fe3O4@PPy nanoparticles by a novel one-pot route

Stable magnetic nanofluids containing Fe3O4@Polypyrrole (PPy) nanoparticles (NPs) were prepared by using a facile and novel method, in which one-pot route was used. FeCl3·6H2O was applied as the iron source, and the oxidizing agent to produce PPy. Trisodium citrate (Na3cit) was used as the reducing reagent to form Fe3O4 NPs. The as-prepared nanofluid can keep long-term stability. The Fe3O4@PPy NPs can still keep dispersing well after the nanofluid has been standing for 1 month and no sedimentation is found. The polymerization reaction of the pyrrole monomers took place with Fe3+ ions as the initiator, in which these Fe3+ ions remained in the solution adsorbed on the surface of the Fe3O4 NPs. Thus, the core-shell NPs of Fe3O4@PPy were obtained. The particle size of the as-prepared Fe3O4@PPy can be easily controlled from 7 to 30 nm by the polymerization reaction of the pyrrole monomers. The steric stabilization and weight of the NPs affect the stability of the nanofluids. The as-prepared Fe3O4@PPy NPs exhibit superparamagnetic behavior

pncA mutations in clinical Mycobacterium tuberculosis isolates from Korea

BACKGROUND: Pyrazinamide (PZA) is among the first-line drugs for the treatment of tuberculosis. In vitro, it kills semidormant mycobacteria only at low pH. The purpose of this study was to compare PZA resistance with pyrazinamidase (PZase) activity and the genotype to better understand the molecular basis of PZA resistance and to expand the profile of pncA mutations worldwide. RESULTS: Of the 28 tested strains of Mycobacterium tuberculosis, 6 were susceptible to PZA and positive for PZase activity and had no pncA mutations. Twenty-one strains were resistant to PZA and negative for PZase activity and had mutations in the pncA gene, including 15 point mutations, 5 insertions, and 2 deletions. One strain had no mutation in the pncA gene, even though it was resistant to PZA and negative for PZase activity. Three isolates had adenine to guanine point mutations in the -11 upstream region, making this the most common type of pncA mutations in this study, with at least two different RFLP patterns. CONCLUSION: These data help in the understanding of the molecular basis of PZA resistance. An adenine to guanine point mutation in the -11 upstream region was the most common type of pncA mutation in our isolates. The results of pncA mutation analyses should be carefully interpreted for epidemiologic purposes

Severe gastric variceal haemorrhage due to splenic artery thrombosis and consecutive arterial bypass

<p>Abstract</p> <p>Background</p> <p>Upper gastrointestinal haemorrhage is mainly caused by ulcers. Gastric varicosis due to portal hypertension can also be held responsible for upper gastrointestinal bleeding. Portal hypertension causes the development of a collateral circulation from the portal to the caval venous system resulting in development of oesophageal and gastric fundus varices. Those may also be held responsible for upper gastrointestinal haemorrhage.</p> <p>Case presentation</p> <p>In this study, we describe the case of a 69-year-old male with recurrent severe upper gastrointestinal bleeding caused by arterial submucosal collaterals due to idiopathic splenic artery thrombosis. The diagnosis was secured using endoscopic duplex ultrasound and angiography. The patient was successfully treated with a laparoscopic splenectomy and complete dissection of the short gastric arteries, resulting in the collapse of the submucosal arteries in the gastric wall. Follow-up gastroscopy was performed on the 12^thpostoperative week and showed no signs of bleeding and a significant reduction in the arterial blood flow within the gastric wall. Subsequent follow-up after 6 months also showed no further gastrointestinal bleeding as well as subjective good quality of life for the patient.</p> <p>Conclusion</p> <p>Submucosal arterial collaterals must be excluded by endosonography via endoscopy in case of recurrent upper gastrointestinal bleeding. Laparoscopic splenectomy provides adequate treatment in preventing any recurrent bleeding, if gastric arterial collaterals are caused by splenic artery thrombosis.</p

Superconducting instabilities of R-charged black branes

We explore superconducting instabilities of black branes in SO(6) gauged supergravity at finite temperature and finite R-charge densities. We compute the critical temperatures for homogeneous neutral and superconducting instabilities in a truncation of 20 scalars and 15 gauge fields as a function of the chemical potentials conjugate to the three U(1) charges in SO(6). We find that despite the imbalance provided by multiple chemical potentials there is always at least one superconducting black brane branch, emerging at a temperature where the normal phase is locally thermodynamically stable. We emphasise that the three-equal charge solution, Reissner-Nordstrom, is subdominant to a thermodynamically unstable black brane at sufficiently low temperatures --- a feature which is hidden in an equal charge truncation.Comment: 23 pages, 6 figure

Eating Disorder Behaviors Are Increasing: Findings from Two Sequential Community Surveys in South Australia

Background: evidence for an increase in the prevalence of eating disorders is inconsistent. Our aim was to determine change in the population point prevalence of eating disorder behaviors over a 10-year period. \ud \ud Methodology/Principal Findings: eating disorder behaviors were assessed in consecutive general population surveys of men and women conducted in 1995 (n = 3001, 72% respondents) and 2005 (n = 3047, 63.1% respondents). Participants were randomly sampled from households in rural and metropolitan South Australia. There was a significant (all p,0.01) and over two-fold increase in the prevalence of binge eating, purging (self-induced vomiting and/or laxative or diuretic misuse) and strict dieting or fasting for weight or shape control among both genders. The most common diagnosis in 2005 was either binge eating disorder or other ‘‘eating\ud disorders not otherwise specified’’ (EDNOS; n = 119, 4.2%). \ud \ud Conclusions/Significance: in this population sample the point prevalence of eating disorder behaviors increased over the past decade. Cases of anorexia nervosa and bulimia nervosa, as currently defined, remain uncommon

The 2010 Antarctic ozone hole: Observed reduction in ozone destruction by minor sudden stratospheric warmings

Satellite observations show that the 2010 Antarctic ozone hole is characterized by anomalously small amounts of photochemical ozone destruction (40-60% less than the 2005-2009 average). Observations from the MLS instrument show that this is mainly related to reduced photochemical ozone destruction between 20-25 km altitude. Lower down between 15-20 km the atmospheric chemical composition and photochemical ozone destruction is unaffected. The modified chemical composition and chemistry between 20-25 km altitude in 2010 is related to the occurrence of a mid-winter minor Antarctic Sudden Stratospheric Warming (SSW). The measurements indicate that the changes in chemical composition are related to downward motion of air masses rather than horizontal mixing, and affect stratospheric chemistry for several months. Since 1979, years with similar anomalously small amounts of ozone destruction are all characterized by either minor or major SSWs, illustrating that their presence has been a necessary pre-condition for reduced Antarctic stratospheric ozone destruction