729 research outputs found

    Heat Transfer Analysis and Assessment of Kinetics Systems for PBX 9501

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    The study of thermal decomposition in high explosive (HE) charges has been an ongoing process since the early 1900s. This work is specifically directed towards the analysis of PBX 9501. In the early 1970s, Dwight Jaeger of Los Alamos National Laboratory (LANL) developed a single-step, two-species kinetics system that was used in the development of one of the first finite element codes for thermal analyses known as EXPLO. Jaeger's research focused on unconfined spherical samples of HE charges to determine if varied heating ramps would cause detonation or deflagration. Tarver and McGuire of Lawrence Livermore National Laboratory (LLNL) followed soon after with a three-step, four-species kinetics system that was developed for confined spheres under relatively fast heating conditions. Peter Dickson et al. of LANL then introduced a kinetics system with four steps and five species that included bimolecular products to capture the effects of the endothermic phase change that the HE undergoes. The results of four experiments are examined to study the effectiveness of these kinetics systems. The experiments are: (1) The LLNL scaled thermal explosion (STEX) experiments on confined cylindrical charges with long heating ramps in the range of 90 hours. (2) The LLNL one-dimensional time to explosion (ODTX) experiments on spherical charges that include confined, partially confined, and aged HE experiments. (3) The LANL unconfined one-dimensional experiments for small spheres. (4) The Naval Air Warfare Center Weapons Division at China Lake experiments on small confined cylinders. The three kinetics systems are applied to each of the four experiments with the use of the finite element analysis (FEA) heat conduction solver COYOTE. The numerical results using the kinetics systems are compared to each other and to the experimental data to determine which kinetics systems are best suited for analyzing conditions such as time to ignition, containment, heating time, and location of ignition

    Generalized Seizure in a Mauritian Woman Taking Bupropion

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    A 24-y-old woman was admitted to the emergency department having had a generalized seizure (acute loss of consciousness, convulsive movements of her arms and legs, and confusion on regaining consciousness). She was on the sixth day of treatment with 300 mg daily of slow-release bupropion (Zyban SR) as an aid to smoking cessation. She had a past medical history of tonsillectomy and hay fever, for which she was taking budesonide nasal drops (two drops daily, each drop 200 mcg). She was on no other medication. There was no history of head trauma, liver disease, or alcohol withdrawal. Clinical examination, including neurological examination, was normal. The patient's weight was 48 kg. Her blood pressure was 130/80 mm Hg. Electrocardiogram showed a sinus tachycardia at 102 beats per minute. Radiography of the skull and a computed tomography scan of the brain without contrast were both normal. The patient's blood glucose, urea, electrolytes, and liver function tests were all normal. Her serum calcium was 2.01 mmol/l (normal range, 2.0–2.6 mmol/l) and her hemoglobin was 116 g/l (normal range, 120–140 g/l). The bupropion was discontinued, and the patient recovered without any further seizures or other neurological sequelae

    Is a combination of varenicline and nicotine patch more effective in helping smokers quit than varenicline alone? A randomised controlled trial

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    This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited

    Real World Study to Evaluate the Effectiveness of Varenicline and Cognitive-Behavioural Interventions for Smoking Cessation

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    A prospective pragmatic interventional study was conducted to evaluate the effectiveness of varenicline for smoking cessation among a cohort of motivated smokers attending two smoking cessation clinics. Smokers between 18 and 65 years who had smoked 10 or more cigarettes per day were included. All participants received cognitive-behavioural varenicline according to approved dose and prescriptions. Continuous abstinence, validated by exhaled CO levels, was assessed in each control. A total of 264 smokers – 155 males (58.7%) and 109 females (41.3%) – were included. Mean age was 43.7, amount smoked was 23 cigarettes per day and 61.4% had at least one prior attempt to quit. The continuous abstinence rate at end of treatment (12 wks) was 58.3%. Conclusions: varenicline and cognitive-behavioural intervention are effective for smoking cessation with high continuous abstinence rates when are used in a clinical setting

    Use of a liquid nicotine delivery product to promote smoking cessation

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    <p>Abstract</p> <p>Background</p> <p>Despite access to various pharmacotherapies and counseling support to aid cessation, smokers typically demonstrate quit rates below 50%. This report describes the results of a Phase 2a study exploring the efficacy of a liquid nicotine delivery system as an aid to smoking cessation assessed after 12 weeks of therapy.</p> <p>Methods</p> <p>A single-arm Phase 2a study was conducted. Community-based smokers (ages 18+ years, smoking at least 10 cigarettes daily for the past year and interested in making a quit attempt) were recruited and completed clinic visits at 2 week intervals over the 12 week study period where carbon monoxide levels were assessed and the Smoke-Break product was rated on taste and overall satisfaction. Participants were provided with a supply of liquid nicotine cigarettes (e.g., Smoke-Break) at each clinic visit. A total of 69 smokers were enrolled and received the intervention product (intention to treat group, ITT) and 52 smokers verified participation (according to protocol group, ATP).</p> <p>Results</p> <p>The cessation rate at 12 weeks after the baseline visit, assessed as the bioverified point prevalence of abstinence, was 71.1% (95% confidence interval [CI] 58.8%-83.5%) in the ATP group and 53.6% (41.8%-65.4%) in the ITT group. Participants rated the liquid nicotine delivery system highly and also expressed general satisfaction. Few adverse events were identified with no serious adverse events.</p> <p>Conclusions</p> <p>These results support the efficacy of the liquid nicotine delivery system in smoking cessation. If this nicotine delivery product proves to be effective in larger trials, it could represent an inexpensive, readily accessible and well-tolerated agent to promote smoking cessation.</p> <p>Trial Registration</p> <p>This trial is registered at clinicaltrials.gov as study NCT00715871.</p

    Visual hallucinations associated with varenicline: a case report

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    <p>Abstract</p> <p>Introduction</p> <p>Varenicline is widely used for smoking cessation. It has shown efficacy over placebo and bupropion in manufacturer-sponsored trials. Those with mental illness were excluded from these trials. There are case reports of exacerbation of mental illness and development of psychiatric symptoms with varenicline use.</p> <p>Case presentation</p> <p>A 61-year-old male Caucasian being treated for post-traumatic stress disorder, depression not otherwise specified and alcohol dependence, was prescribed varenicline while he was in a post-traumatic stress disorder/alcohol dual diagnosis treatment program. He developed visual hallucinations, which became worse with titration of the medication. These symptoms resolved upon discontinuation of varenicline.</p> <p>Conclusion</p> <p>Patients with mental illness have a higher incidence of nicotine dependence, and attempts should be made for smoking cessation. Varenicline has not been widely tested in this population. There are reports of exacerbation of mental illness, and probable causation of psychiatric symptoms in the mentally ill. Providers should be aware of this possibility and advise their patients appropriately.</p
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