CT dose reduction factors in the thousands using X-ray phase contrast

Phase-contrast X-ray imaging can improve the visibility of weakly absorbing objects (e.g. soft tissues) by an order of magnitude or more compared to conventional radiographs. Previously, it has been shown that combining phase retrieval with computed tomography (CT) can increase the signal-to-noise ratio (SNR) by up to two orders of magnitude over conventional CT at the same radiation dose, without loss of image quality. Our experiments reveal that as radiation dose decreases, the relative improvement in SNR increases. We discovered this enhancement can be traded for a reduction in dose greater than the square of the gain in SNR. Upon reducing the dose 300 fold, the phase-retrieved SNR was still almost 10 times larger than the absorption contrast data. This reveals the potential for dose reduction factors in the tens of thousands without loss in image quality, which would have a profound impact on medical and industrial imaging applications

ZACCAROBOL / ZBOL – UM OLHAR HISTÓRICO, TÉCNICO E FISIOLÓGICO DA MODALIDADE

O objetivo deste estudo foi apresentar o Zaccarobol como modalidade esportiva presente no contexto dos esportes nacionais, seu contexto histórico e suas especificidades a nível metabólico. A pesquisa caracteriza-se como qualitativa e bibliográfica, além de apresentar comparações com o Voleibol, devido a suas proximidades. O Zbol apresenta-se como modalidade esportiva para fins de ganho de qualidade de vida e de cunho de alto rendimento. Criado na década de 90, pelo professor Sérgio Plaster Zaccaro, o esporte veio se desenvolvendo e se aprimorando até os dias atuais, bem como seu formato de jogo similar ao voleibol. Essa comparação se dá por uma grande aproximação de demandas motoras, padrão de jogo e via metabólica requisitada se comparada com o sistema de jogo de ambos os esportes. Zbol e Voleibol apresentam capacidades condicionantes e coordenativas equivalentes, bem como o uso predominante da via anaeróbica alática como produtora de energia, analisando períodos de esforços intensos de curta duração precedidos de pausas com movimentos de menor intensidade que possibilitam a recuperação. O estudo contempla aspectos fisiológicos pertinentes ao uso da modalidade devidamente comparados e relatados literariamente

Nachweis und Quantifizierung von Drogen und anderen Fremdstoffen in Blutspuren auf verschiedenen Trägermaterialien

Es wurde ein gaschromatographisch-massenspektrometrisches (GC/MS)-Verfahren zum Screening und Nachweis von Morphin (4,5alpha-Epoxy-17-methyl-7-morphinen-3,6alpha-diol), Codein (4,5alpha-Epoxy-3-methoxy-17-methyl-7-morphinen-6alpha-ol), Heroin (4,5alpha-Epoxy-17-methyl-7-morphinen-3,6alpha-diyldiacetat), Kokain ((-)-Methyl-[3beta-benzoyloxy-2beta(1alphaH,5alphaH)-tropancarboxylat]), Benzoylecgonin (Tropin-2-carbonsäure-benzoylester, Methylecgonin (Tropin-3-carbonsäure-methylester), Cocethylen ((-)-Ethyl-[3beta-benzoyloxy-2beta(1alphaH,5alphaH)-tropancarboxylat]), THC (Delta-9-tetrahydrocannabinol), THC-Carbonsäure (11-Nor-9-carboxy-delta-9-tetrahydrocannabinol),, 11-OH-THC (11-hydroxy-delta-9-tetrahydrocannabinol), Amphetamin ((±)-alpha-Methylphenethylamin), Methamphetamin (N,alpha-Dimethylphenethylamin), MDA (Methylendioxyamphetamin; Tenamfetamin, alpha-Methyl-3,4-methylendioxy-phenethylamin), MDMA (Methylendioxymethamphetamin; N,alpha-Dimethyl-3,4-methylendioxy-phenethylamin) und MBDB (N-Methylbenzodioxazolylbutanamin) in kleinen Blutproben und Blutspuren unter Verwendung von Festphasen-SPE-Säulen und einem Pipettierroboter (Gilson Aspec XL) beschrieben. Die Nachweisgrenzen liegen zwischen 1,62 und 4,10 ng / 50 µl Spot (Amphetaminderivate), 0,15 und 0,82 ng / 50 µl Spot (Cannabinoide), 1,67 – 4,70 ng / 50 µl Spot (Kokain und dessen Derivate) sowie 4,53 und 4,91 ng / 50 µl Spot (Opiate) und die Korrelationsfaktoren zwischen 0,9957 und 0,9999. Weiterhin wurde die Nachweisbarkeit auf verschiedenen Spurenträgern (Holz, Stoff (Textil), Metall, Fliesen und Glas) untersucht. Dabei ergab sich, dass ein qualitativer Nachweis noch nach mindestens 64 Tagen möglich war, die quantitative Bestimmung jedoch auf Schwierigkeiten stieß. Ursachen hierfür sind beispielsweise Chargenunterschiede der Säulenmaterialien und andere Effekte, die beim Arbeiten im spurenanalytischen Bereich in der Nähe der Nachweis- und unteren Bestimmungsgrenze von großem Einfluss sind. Mit Hilfe der im Rahmen dieser Arbeit entwickelten Methode konnten 2 spektakuläre Kriminalfälle aufgeklärt werden.A GC/MS-method is developed for the screening and detection of morphine (4,5a-epoxy-17-methyl-7-morphinen-3,6a-diol), codeine (4,5a-epoxy-3-methoxy-17-methyl-7-morphinen-6a-ol), heroin (4,5a-epoxy-17-methyl-7-morphinen-3,6a-diyldiacetate), cocaine ((-)-methyl-[3beta-benzoyloxy-2ß(1alphaH,5alphaH)-tropancarboxylate]), benzoylecgonine (tropin-2-carboxylic acid-benzoylester, methylecgonin (tropin-3-carboxylic acid-methylester), cocethylene ((-)-ethyl-[3beta-benzoyloxy-2beta(1alphaH,5alphaH)-tropancarboxylate]), THC (delta-9-tetrahydrocannabinol), THC-carbonic acid (11-Nor-9-carboxy-delta-9-tetrahydrocannabinol), 11-OH-THC (11-hydroxy-delta-9-tetrahydrocannabinol), amphetamine ((±)-alpha-methylphenethylamine), methamphetamin (N,alpha-dimethylphenethylamine), MDA (methylendioxyamphetamine; tenamfetamine, alpha-methyl-3,4-methylendioxy-phenethylamine), MDMA (methylenedioxymethamphetamine; N,alpha-dimethyl-3,4-methylendioxy-phenethylamine) und MBDB (N-methylbenzodioxazolylbutanamine) in small blood samples and bloodstains using solid phase SPE columns and a pipetting robot (Gilson Aspec XL). The detection limits are in the order of 1.62 – 4.10 ng / 50 µl spot (amphetamines), 0.15 – 0.82 ng / 50 µl spot (cannabinoids), 1.67 – 4.70 ng / 50 µl spot (cocaine and derivatives) and 4.53 – 4.91 ng / 50 µl spot (opiates) and the correlation factors are between 0.9957 and 0.9999. The method has proven useful in forensic cases with only small sample volumes or bloodstains. Furthermore the detectability was tested using different trace-carriers (wood, textiles, metal, floor-tiles und glass). These investigations resulted in qualitative detectabilities within at least 64 days. The quantitative determination however raised difficulties, mainly caused by different brands of columns and other effects which are of important influence when working in the analytical range near the detection- and lower determination limit, respectively. By means of the methods developed within the scope of this study, two spectacular crime cases could be cleared up

Increasing Respiratory Effort With 100% Oxygen During Resuscitation of Preterm Rabbits at Birth

Background: Spontaneous breathing is essential for successful non-invasive respiratory support delivered by a facemask at birth. As hypoxia is a potent inhibitor of spontaneous breathing, initiating respiratory support with a high fraction of inspired O2 may reduce the risk of hypoxia and increase respiratory effort at birth. Methods: Preterm rabbit kittens (29 days gestation, term ~32 days) were delivered and randomized to receive continuous positive airway pressure with either 21% (n = 12) or 100% O2 (n = 8) via a facemask. If apnea occurred, intermittent positive pressure ventilation (iPPV) was applied with either 21% or 100% O2 in kittens who started in 21% O2, and remained at 100% O2 for kittens who started the experiment in 100% O2. Respiratory rate (breaths per minute, bpm) and variability in inter-breath interval (%) were measured from esophageal pressure recordings and functional residual capacity (FRC) was measured from synchrotron phase-contrast X-ray images. Results: Initially, kittens receiving 21% O2 had a significantly lower respiratory rate and higher variability in inter-breath interval, indicating a less stable breathing pattern than kittens starting in 100% O2 [median (IQR) respiratory rate: 16 (4–28) vs. 38 (29–46) bpm, p = 0.001; variability in inter-breath interval: 33.3% (17.2–50.1%) vs. 27.5% (18.6–36.3%), p = 0.009]. Apnea that required iPPV, was more frequently observed in kittens in whom resuscitation was started with 21% compared to 100% O2 (11/12 vs. 1/8, p = 0.001). After recovering from apnea, respiratory rate was significantly lower and variability in inter-breath interval was significantly higher in kittens who received iPPV with 21% compared to 100% O2. FRC was not different between study groups at both timepoints. Conclusion: Initiating resuscitation with 100% O2 resulted in increased respiratory activity and stability, thereby reducing the risk of apnea and need for iPPV after birth. Further studies in human preterm infants are mandatory to confirm the benefit of this approach in terms of oxygenation. In addition, the ability to avoid hyperoxia after initiation of resuscitation with 100% oxygen, using a titration protocol based on oxygen saturation, needs to be clarified

Salmonella enterica Serovar Typhimurium Exploits Inflammation to Compete with the Intestinal Microbiota

Most mucosal surfaces of the mammalian body are colonized by microbial communities (“microbiota”). A high density of commensal microbiota inhabits the intestine and shields from infection (“colonization resistance”). The virulence strategies allowing enteropathogenic bacteria to successfully compete with the microbiota and overcome colonization resistance are poorly understood. Here, we investigated manipulation of the intestinal microbiota by the enteropathogenic bacterium Salmonella enterica subspecies 1 serovar Typhimurium (S. Tm) in a mouse colitis model: we found that inflammatory host responses induced by S. Tm changed microbiota composition and suppressed its growth. In contrast to wild-type S. Tm, an avirulent invGsseD mutant failing to trigger colitis was outcompeted by the microbiota. This competitive defect was reverted if inflammation was provided concomitantly by mixed infection with wild-type S. Tm or in mice (IL10−/−, VILLIN-HACL4-CD8) with inflammatory bowel disease. Thus, inflammation is necessary and sufficient for overcoming colonization resistance. This reveals a new concept in infectious disease: in contrast to current thinking, inflammation is not always detrimental for the pathogen. Triggering the host's immune defence can shift the balance between the protective microbiota and the pathogen in favour of the pathogen

The organisation and delivery of health improvement in general practice and primary care: a scoping study

Background This project examines the organisation and delivery of health improvement activities by and within general practice and the primary health-care team. The project was designed to examine who delivers these interventions, where they are located, what approaches are developed in practices, how individual practices and the primary health-care team organise such public health activities, and how these contribute to health improvement. Our focus was on health promotion and ill-health prevention activities. Aims The aim of this scoping exercise was to identify the current extent of knowledge about the health improvement activities in general practice and the wider primary health-care team. The key objectives were to provide an overview of the range and type of health improvement activities, identify gaps in knowledge and areas for further empirical research. Our specific research objectives were to map the range and type of health improvement activity undertaken by general practice staff and the primary health-care team based within general practice; to scope the literature on health improvement in general practice or undertaken by health-care staff based in general practice and identify gaps in the evidence base; to synthesise the literature and identify effective approaches to the delivery and organisation of health improvement interventions in a general practice setting; and to identify the priority areas for research as defined by those working in general practice. Methods We undertook a comprehensive search of the literature. We followed a staged selection process involving reviews of titles and abstracts. This resulted in the identification of 1140 papers for data extraction, with 658 of these papers selected for inclusion in the review, of which 347 were included in the evidence synthesis. We also undertook 45 individual and two group interviews with primary health-care staff. Findings Many of the research studies reviewed had some details about the type, process or location, or who provided the intervention. Generally, however, little attention is paid in the literature to examining the impact of the organisational context on the way services are delivered or how this affects the effectiveness of health improvement interventions in general practice. We found that the focus of attention is mainly on individual prevention approaches, with practices engaging in both primary and secondary prevention. The range of activities suggests that general practitioners do not take a population approach but focus on individual patients. However, it is clear that many general practitioners see health promotion as an integral part of practice, whether as individual approaches to primary or secondary health improvement or as a practice-based approach to improving the health of their patients. Our key conclusion is that there is currently insufficient good evidence to support many of the health improvement interventions undertaken in general practice and primary care more widely. Future Research Future research on health improvement in general practice and by the primary health-care team needs to move beyond clinical research to include delivery systems and be conducted in a primary care setting. More research needs to examine areas where there are chronic disease burdens – cancer, dementia and other disabilities of old age. Reviews should be commissioned that examine the whole prevention pathway for health problems that are managed within primary care drawing together research from general practice, pharmacy, community engagement, etc

Dietary advice for reducing cardiovascular risk

Background Changes in population diet are likely to reduce cardiovascular disease and cancer, but the effect of dietary advice is uncertain. This review is an update of a previous review published in 2007. Objectives To assess the effects of providing dietary advice to achieve sustained dietary changes or improved cardiovascular risk profile among healthy adults. Search methods We searched the Cochrane Central Register of Controlled Trials, the Database of Abstracts of Reviews of Effects (DARE) and the HTA database on The Cochrane Library (Issue 4, 2010). We searched MEDLINE (Ovid) (1950 to week 2 October 2010) and EMBASE (Ovid) (1980 to Week 42 2010). Additional searches were done on CAB Health (1972 to December 1999), CVRCT registry (2000), CCT (2000) and SIGLE (1980 to 2000). Dissertation abstracts and reference lists of articles were checked and researchers were contacted. Selection criteria Randomised studies with no more than 20% loss to follow-up, lasting at least three months and involving healthy adults comparing dietary advice with no advice or minimal advice. Trials involving children, trials to reduce weight or those involving supplementation were excluded. Data collection and analysis Two review authors independently assessed trial quality and extracted data. Study authors were contacted for additional information. Main results Forty-four trials with 52 intervention arms (comparisons) comparing dietary advice with no advice were included in the review; 18,175 participants or clusters were randomised. Twenty-nine of the 44 included trials were conducted in the USA. Dietary advice reduced total serum cholesterol by 0.15 mmol/L (95% CI 0.06 to 0.23) and LDL cholesterol by 0.16 mmol/L (95% CI 0.08 to 0.24) after 3 to 24 months. Mean HDL cholesterol levels and triglyceride levels were unchanged. Dietary advice reduced blood pressure by 2.61 mm Hg systolic (95% CI 1.31 to 3.91) and 1.45 mm Hg diastolic (95% CI 0.68 to 2.22) and 24-hour urinary sodium excretion by 40.9 mmol (95% CI 25.3 to 56.5) after 3 to 36 months but there was heterogeneity between trials for the latter outcome. Three trials reported plasma antioxidants, where small increases were seen in lutein and β-cryptoxanthin, but there was heterogeneity in the trial effects. Self-reported dietary intake may be subject to reporting bias, and there was significant heterogeneity in all the following analyses. Compared to no advice, dietary advice increased fruit and vegetable intake by 1.18 servings/day (95% CI 0.65 to 1.71). Dietary fibre intake increased with advice by 6.5 g/day (95% CI 2.2 to 10.82), while total dietary fat as a percentage of total energy intake fell by 4.48% (95% CI 2.47 to 6.48) with dietary advice, and saturated fat intake fell by 2.39% (95% CI 1.4 to 3.37). Two trials analysed incident cardiovascular disease (CVD) events (TOHP I/II). Follow-up was 77% complete at 10 to 15 years after the end of the intervention period and estimates of event rates lacked precision but suggested that sodium restriction advice probably led to a reduction in cardiovascular events (combined fatal plus non-fatal events) plus revascularisation (TOHP I hazards ratio (HR) 0.59, 95% CI 0.33 to 1.08; TOHP II HR 0.81, 95% CI 0.59 to 1.12). Authors' conclusions Dietary advice appears to be effective in bringing about modest beneficial changes in diet and cardiovascular risk factors over approximately 12 months, but longer-term effects are not known

The Zinc-Dependent Protease Activity of the Botulinum Neurotoxins

The botulinum neurotoxins (BoNT, serotypes A-G) are some of the most toxic proteins known and are the causative agents of botulism. Following exposure, the neurotoxin binds and enters peripheral cholinergic nerve endings and specifically and selectively cleaves one or more SNARE proteins to produce flaccid paralysis. This review centers on the kinetics of the Zn-dependent proteolytic activities of these neurotoxins, and briefly describes inhibitors, activators and factors underlying persistence of toxin action. Some of the structural, enzymatic and inhibitor data that are discussed here are available at the botulinum neurotoxin resource, BotDB (http://botdb.abcc.ncifcrf.gov)