105 research outputs found

    USING GASEOUS EMISSIONS OF A PROTON ACCELERATOR FACILITY AS TRACER FOR SMALL-SCALE ATMOSPHERIC DISPERSION

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    The gaseous effluents of the proton accelerator facility located in the Western part of the Paul Scherrer Institute, Aargau, Switzerland, contain a mixture of positron emitters (50 % 15O, 20 % 13N and 30 % 11C). For the experimental verification of a future upgrade of the dispersion model in the complex topography of the Aare valley, a measuring campaign using three continuous gamma-spectrometric measuring stations was launched in 2011. The concept of a modified man-made-gross-count (MMGC) ratio yields a clear signal associated with the positron emitters while minimising the influence of radon progeny rain-out events. A dependence of the measured MMGC ratios on the emitted activity and wind direction could be demonstrated using frequency distributions of the modified MMGC ratio measured in 2012 and 2013. A significant fraction of high MMGC-ratio values was found associated with dispersion directions (based on measurements of the wind direction in 70 m above ground) not towards or even against the direction between stack and measuring statio

    Analytical expressions for the conductance noise measured with four circular contacts placed in a square array

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    In the ideal case, noise measurements with four contacts minimize the contribution of the contact interface. There is a need to characterize conductance noise and noise correction factors for the different geometries provided with four contacts, as already is the case for resistivity measurements with van der Pauw structures. Here, we calculate the noise correction factors for two geometries with a pair of sensors and a pair of current driver electrodes placed in a square array. The first geometry investigated is a very large film compared to the distance L between four circular electrodes, which are placed in a square array far away from the borders of the film. The second is a square-shaped conductive film with side length L and provided with four quarter-circle corner contacts with radius l. The effect of the conductance noise in the film can be observed between current free sensors in a four-point measurement or between current carrying drivers in a two-point measurement. Our analytical expressions are based on approximations to solve the integrals (J·)2dA and |J|4dA for the voltage noise measured across a pair of sensors, SVQ, and across the drivers, SVD, respectively. The first and second integrands represent the squared dot product of the current density and adjoint current density and the modulus of the current density to the fourth power, respectively. The current density J in the samples is due to the current I passing through the driver contacts. The calculated expressions are applicable to samples with thickness tl0.1L. Hence, the disturbances in the neighborhood of the sensors on J and of the drivers on are ignored. Noise correction factors for two- and four-point measurements are calculated for sensors on an equipotential (transversal noise) with the driver contacts on the diagonal of a square and for sensors next to each other on one side of the square with the drivers next to each other on the other side of the square (longitudinal noise). In all cases the noise between the sensors is smaller and less sensitive to the contact size 2l/L than the noise between the drivers. The ratio SVQ/SVD becomes smaller with smaller contact radius l. Smaller sensors give a better suppression of interface noise at the contacts. But overly low 2l/L values result in overly high resistance between the sensors and too strong a contribution of thermal noise at the sensors. Therefore, equations are derived to calculate the current level needed to observe 1/f conductance fluctuations on top of the thermal noise. The results from the calculated analytical expressions show good agreement with experimental results obtained from the noise in carbon sheet resistance and numerical results. Transversal noise measurements on a square sample with corner contacts are recommended to characterize the 1/f noise of the layer. This is due to the increased current densities in the sample compared to the open structure, which result in easier detection of the 1/f on top of the thermal noise. ©2007 American Institute of Physic

    Clinical and biochemical effects of a combination botanical product (ClearGuardℱ) for allergy: a pilot randomized double-blind placebo-controlled trial

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    <p>Abstract</p> <p>Background</p> <p>Botanical products are frequently used for treatment of nasal allergy. Three of these substances, <it>Cinnamomum zeylanicum</it>, <it>Malpighia glabra</it>, and <it>Bidens pilosa</it>, have been shown to have a number of anti-allergic properties <it>in-vitro</it>. The current study was conducted to determine the effects of these combined ingredients upon the nasal response to allergen challenge in patients with seasonal allergic rhinitis.</p> <p>Methods</p> <p>Twenty subjects were randomized to receive the combination botanical product, (CBP) 2 tablets three times a day, loratadine, 10 mg once a day in the morning, or placebo, using a randomized, double-blinded crossover design. Following 2 days of each treatment and during the third day of treatment, subjects underwent a nasal allergen challenge (NAC), in which nasal symptoms were assessed after each challenge dose and every 2 hours for 8 hours. Nasal lavage fluid was assessed for tryptase, prostaglandin D2, and leukotriene E4 concentrations and inflammatory cells.</p> <p>Results</p> <p>Loratadine significantly reduced the total nasal symptom score during the NAC compared with placebo (P = 0.04) while the CBP did not. During the 8 hour period following NAC, loratadine and the CBP both reduced NSS compared with placebo (P = 0.034 and P = 0.029, respectively). Analysis of nasal lavage fluid demonstrated that the CBP prevented the increase in prostaglandin D2 release following NAC, while neither loratadine nor placebo had this effect. None of the treatments significantly affected tryptase or leukotriene E4 release or inflammatory cell infiltration.</p> <p>Conclusion</p> <p>The CBP significantly reduced NSS during the 8 hours following NAC and marginally inhibited the release of prostaglandin D2 into nasal lavage fluid, suggesting potential clinical utility in patients with allergic rhinitis.</p

    Nutritional and herbal supplements for anxiety and anxiety-related disorders: systematic review

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    <p>Abstract</p> <p>Background</p> <p>Over the past several decades, complementary and alternative medications have increasingly become a part of everyday treatment. With the rising cost of prescription medications and their production of unwanted side effects, patients are exploring herbal and other natural remedies for the management and treatment of psychological conditions. Psychological disorders are one of the most frequent conditions seen by clinicians, and often require a long-term regimen of prescription medications. Approximately 6.8 million Americans suffer from generalized anxiety disorder. Many also suffer from the spectrum of behavioural and physical side effects that often accompany its treatment. It is not surprising that there is universal interest in finding effective natural anxiolytic (anti-anxiety) treatments with a lower risk of adverse effects or withdrawal.</p> <p>Methods</p> <p>An electronic and manual search was performed through MEDLINE/PubMed and EBSCO. Articles were not discriminated by date of publication. Available clinical studies published in English that used human participants and examined the anxiolytic potential of dietary and herbal supplements were included. Data were extracted and compiled into tables that included the study design, sample population, intervention, control, length of treatment, outcomes, direction of evidence, and reported adverse events.</p> <p>Results</p> <p>A total of 24 studies that investigated five different CAM monotherapies and eight different combination treatments and involved 2619 participants met the inclusion criteria and were analyzed. There were 21 randomized controlled trials and three open-label, uncontrolled observational studies. Most studies involved patients who had been diagnosed with either an anxiety disorder or depression (n = 1786). However, eight studies used healthy volunteers (n = 877) who had normal levels of anxiety, were undergoing surgery, tested at the upper limit of the normal range of a trait anxiety scale, had adverse premenstrual symptoms or were peri-menopausal, reported anxiety and insomnia, or had one month or more of elevated generalized anxiety. Heterogeneity and the small number of studies for each supplement or combination therapy prevented a formal meta-analysis. Of the randomized controlled trials reviewed, 71% (15 out of 21) showed a positive direction of evidence. Any reported side effects were mild to moderate.</p> <p>Conclusions</p> <p>Based on the available evidence, it appears that nutritional and herbal supplementation is an effective method for treating anxiety and anxiety-related conditions without the risk of serious side effects. There is the possibility that any positive effects seen could be due to a placebo effect, which may have a significant psychological impact on participants with mental disorders. However, based on this systematic review, strong evidence exists for the use of herbal supplements containing extracts of passionflower or kava and combinations of L-lysine and L-arginine as treatments for anxiety symptoms and disorders. Magnesium-containing supplements and other herbal combinations may hold promise, but more research is needed before these products can be recommended to patients. St. John's wort monotherapy has insufficient evidence for use as an effective anxiolytic treatment.</p

    The instrument suite of the European Spallation Source

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    An overview is provided of the 15 neutron beam instruments making up the initial instrument suite of the European Spallation Source (ESS), and being made available to the neutron user community. The ESS neutron source consists of a high-power accelerator and target station, providing a unique long-pulse time structure of slow neutrons. The design considerations behind the time structure, moderator geometry and instrument layout are presented. The 15-instrument suite consists of two small-angle instruments, two reflectometers, an imaging beamline, two single-crystal diffractometers; one for macromolecular crystallography and one for magnetism, two powder diffractometers, and an engineering diffractometer, as well as an array of five inelastic instruments comprising two chopper spectrometers, an inverse-geometry single-crystal excitations spectrometer, an instrument for vibrational spectroscopy and a high-resolution backscattering spectrometer. The conceptual design, performance and scientific drivers of each of these instruments are described. All of the instruments are designed to provide breakthrough new scientific capability, not currently available at existing facilities, building on the inherent strengths of the ESS long-pulse neutron source of high flux, flexible resolution and large bandwidth. Each of them is predicted to provide world-leading performance at an accelerator power of 2 MW. This technical capability translates into a very broad range of scientific capabilities. The composition of the instrument suite has been chosen to maximise the breadth and depth of the scientific impact o

    New Pharmacological Agents to Aid Smoking Cessation and Tobacco Harm Reduction: What has been Investigated and What is in the Pipeline?

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    A wide range of support is available to help smokers to quit and aid attempts at harm reduction, including three first-line smoking cessation medications: nicotine replacement therapy, varenicline and bupropion. Despite the efficacy of these, there is a continual need to diversify the range of medications so that the needs of tobacco users are met. This paper compares the first-line smoking cessation medications to: 1) two variants of these existing products: new galenic formulations of varenicline and novel nicotine delivery devices; and 2) twenty-four alternative products: cytisine (novel outside of central and eastern Europe), nortriptyline, other tricyclic antidepressants, electronic cigarettes, clonidine (an anxiolytic), other anxiolytics (e.g. buspirone), selective 5-hydroxytryptamine (5-HT) reuptake inhibitors, supplements (e.g. St John’s wort), silver acetate, nicobrevin, modafinil, venlafaxine, monoamine oxidase inhibitors (MAOI), opioid antagonist, nicotinic acetylcholine receptors (nAChR) antagonists, glucose tablets, selective cannabinoid type 1 receptor antagonists, nicotine vaccines, drugs that affect gamma-aminobutyric acid (GABA) transmission, drugs that affect N-methyl-D-aspartate receptors (NMDA), dopamine agonists (e.g. levodopa), pioglitazone (Actos; OMS405), noradrenaline reuptake inhibitors, and the weight management drug lorcaserin. Six criteria are used: relative efficacy, relative safety, relative cost, relative use (overall impact of effective medication use), relative scope (ability to serve new groups of patients), and relative ease of use (ESCUSE). Many of these products are in the early stages of clinical trials, however, cytisine looks most promising in having established efficacy and safety and being of low cost. Electronic cigarettes have become very popular, appear to be efficacious and are safer than smoking, but issues of continued dependence and possible harms need to be considered

    Preoperative cerebrospinal fluid cytokine levels and the risk of postoperative delirium in elderly hip fracture patients

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    Aging and neurodegenerative disease predispose to delirium and are both associated with increased activity of the innate immune system resulting in an imbalance between pro- and anti-inflammatory mediators in the brain. We examined whether hip fracture patients who develop postoperative delirium have altered levels of inflammatory mediators in cerebrospinal fluid (CSF) prior to surgery. Patients were 75 years and older and admitted for surgical repair of an acute hip fracture. CSF samples were collected preoperatively. In an exploratory study, we measured 42 cytokines and chemokines by multiplex analysis. We compared CSF levels between patients with and without postoperative delirium and examined the association between CSF cytokine levels and delirium severity. Delirium was diagnosed with the Confusion Assessment Method; severity of delirium was measured with the Delirium Rating Scale Revised-98. Mann-Whitney U tests or Student t-tests were used for between-group comparisons and the Spearman correlation coefficient was used for correlation analyses. Sixty-one patients were included, of whom 23 patients (37.7%) developed postsurgical delirium. Concentrations of Fms-like tyrosine kinase-3 (P=0.021), Interleukin-1 receptor antagonist (P=0.032) and Interleukin-6 (P=0.005) were significantly lower in patients who developed delirium postoperatively. Our findings fit the hypothesis that delirium after surgery results from a dysfunctional neuroinflammatory response: stressing the role of reduced levels of anti-inflammatory mediators in this process. The Effect of Taurine on Morbidity and Mortality in the Elderly Hip Fracture Patient.Registration number: NCT00497978. Local ethical protocol number: NL16222.094.0

    Basic theory of the LMS adaptive filter: recent developments

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    In the past few years the theory of LMS filtering has gained a number of new insights. The independence assumption has shown to be dispensable, and an almost tight stability criterion is available. These new developments enable a consistent and convincing teaching of adaptive filtering. I. Introduction In 1959 the LMS adaptive filter was devised by Widrow and Hoff [15]. Although in the subsequent four decades numerous alternative adaptive algorithms have been proposed, it is still one of the most efficient algorithms and, due to its simplicity, in widespread use. Current textbooks on adaptive filtering [3,5,10] deal extensively or even exclusively [13] with the LMS algorithm, and many recent publications are still devoted to its analysis [1,6,9,16]. Despite this huge material, a convincing elementary theory of the LMS algorithm is still lacking, and teaching of the discipline has not yet reached the wanted maturity. Current treatments contain concepts, like the &quot;independence assumpti..
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