193 research outputs found

    Trace-gas metabolic versatility of the facultative methanotroph Methylocella silvestris

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    The climate-active gas methane is generated both by biological processes and by thermogenic decomposition of fossil organic material, which forms methane and short-chain alkanes, principally ethane, propane and butane1, 2. In addition to natural sources, environments are exposed to anthropogenic inputs of all these gases from oil and gas extraction and distribution. The gases provide carbon and/or energy for a diverse range of microorganisms that can metabolize them in both anoxic3 and oxic zones. Aerobic methanotrophs, which can assimilate methane, have been considered to be entirely distinct from utilizers of short-chain alkanes, and studies of environments exposed to mixtures of methane and multi-carbon alkanes have assumed that disparate groups of microorganisms are responsible for the metabolism of these gases. Here we describe the mechanism by which a single bacterial strain, Methylocella silvestris, can use methane or propane as a carbon and energy source, documenting a methanotroph that can utilize a short-chain alkane as an alternative to methane. Furthermore, during growth on a mixture of these gases, efficient consumption of both gases occurred at the same time. Two soluble di-iron centre monooxygenase (SDIMO) gene clusters were identified and were found to be differentially expressed during bacterial growth on these gases, although both were required for efficient propane utilization. This report of a methanotroph expressing an additional SDIMO that seems to be uniquely involved in short-chain alkane metabolism suggests that such metabolic flexibility may be important in many environments where methane and short-chain alkanes co-occur

    Transurethral resection of the prostate in Northern Nigeria, problems and prospects

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    <p>Abstract</p> <p>Background</p> <p>Benign prostatic hyperplasia (BPH) is the commonest disease of the urinary tract afflicting the ageing male and is the commonest neoplastic disease in men aged 50 years and above.</p> <p>Transurethral prostatectomy (TURP) is the ultimate treatment of choice for benign prostatic hyperplasia (BPH) due mainly to the preference of minimally invasive surgery, long term relief of symptoms and cost effectiveness. It is however not available to the majority of Nigerians in need of prostatic surgery in Public Health Institutions.</p> <p>Methods</p> <p>The records of patients who underwent prostatectomy in Aminu Kano Teaching Hospital, over the period June 2001 to July 2007 were examined. The bio data of patients and laboratory investigations performed were retrieved.</p> <p>Results</p> <p>Five Hundred and forty two patients were operated upon, out of which 40 were excluded due to open prostatectomy (22 patients), bladder neck stenosis (16 patients) or bladder tumour around the trigon (2 patients). The age range of the patients was 47–110 years with a mean of 67.2 years. 289 patients (80.1%) had urethral catheter in situ at presentation and 11 (3%) patients had suprapubic cystostomy of which only 3 (0.85%) had combined urethral stricture and BPH.</p> <p>Only 131 (26%) had their PSA measured which ranged from 2–100 ng/ml out of which 39(29.8% n = 131) patients had more than 4 ng/ml and cancer of the prostate and 1(0.8%, n = 131) patient had a PSA level of 4 ng/ml and malignant prostate.</p> <p>Hospital stay was 1–32 days (mean 7.9) and the mean follow up period was 5.6 months (range 0–60) and there were 17.5% complications comprising of urinary tract infection (UTI) 7.2%, Orchitis 2.2%, urinary incontinence 0.6%, atonic bladder 1%, erectile dysfunction 0.6%, cerebrovascular accident 0.4%, myocardial infarction 0.4%, deep vein thrombosis 0.4% and disseminated intravascular coagulopathy (DIC) 0.6% and 1.2% mortality. The cost of treatment inclusive of pre-admission investigations was US615.00(rangeUS 615.00 (range US 300–1,300)</p> <p>Conclusion</p> <p>Despite advances in minimally invasive therapy for LUTH/BPH, TURP is the optimum treatment of choice for the ageing male of sub-Saharan Africa. It is however not available to the majority of patients in this region due to poor health allocation and inadequate facilities and training.</p

    Attentional modulations of the early and later stages of the neural processing of visual completion

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    The brain effortlessly recognizes objects even when the visual information belonging to an object is widely separated, as well demonstrated by the Kanizsa-type illusory contours (ICs), in which a contour is perceived despite the fragments of the contour being separated by gaps. Such large-range visual completion has long been thought to be preattentive, whereas its dependence on top-down influences remains unclear. Here, we report separate modulations by spatial attention and task relevance on the neural activities in response to the ICs. IC-sensitive event-related potentials that were localized to the lateral occipital cortex were modulated by spatial attention at an early processing stage (130–166 ms after stimulus onset) and modulated by task relevance at a later processing stage (234–290 ms). These results not only demonstrate top-down attentional influences on the neural processing of ICs but also elucidate the characteristics of the attentional modulations that occur in different phases of IC processing

    Parental attributions of control for child behaviour and their relation to discipline practices in parents of children with and without developmental delays

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    Children with developmental delays (DD) are at risk for developing behavior problems. Research suggests that parents’ causal attributions for child behavior are related to parenting. This study investigated this association in parents of children with DD compared to parents of typically developing (TD) children. It specifically focused on attributions of child control by separating these from attributions of responsibility, blame and intent, and from attributions of parent control and responsibility. Fifty-one parents of children with DD and 69 parents of TD children completed two questionnaires. The Written Analogue Questionnaire measured causal attributions. The Parenting Scale measured dysfunctional discipline practices. Parents of children with DD viewed the child’s role in problematic behavior more positively while also viewing misbehavior as more fixed than parents of TD children. Parents of TD children who viewed their child as more in control over misbehavior used less dysfunctional discipline, but this association was not found for parents of children with DD. The results advance understanding of how parents perceive behavior problems in children with DD and the important role these perceptions play in parental behavior management strategies. More importantly, these perceptions relate to discipline practices differently for parents of children with DD compared to parents of TD children, highlighting that parent interventions should be adapted to the specific needs of parents of children with DD

    High density of peritumoral lymphatic vessels is a potential prognostic marker of endometrial carcinoma: a clinical immunohistochemical method study

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    <p>Abstract</p> <p>Background</p> <p>The lymphatic system is a major route for cancer cell dissemination and also a potential target for antitumor therapy. To investigate whether increased lymphatic vessel density (LVD) is a prognostic factor for nodal metastasis and survival, we studied peritumoral LVD (P-LVD) and intratumoral LVD (I-LVD) in samples from 102 patients with endometrial carcinoma;</p> <p>Methods</p> <p>Endometrial carcinoma tissues were analyzed for lymphatic vessels by immunohistochemical staining with an antibody against LYVE-1. Univariate analysis was performed with Kaplan-Meier life-table curves to estimate survival, and was compared using the log rank test. Prognostic models used multivariate Cox regression analysis for multivariate analyses of survival;</p> <p>Results</p> <p>Our study showed that P-LVD, but not I-LVD, was significantly correlated with lymph vascular space invasion (LVSI), lymph node metastasis, tumor stage, and CD44 expression in endometrial carcinoma. Moreover, P-LVD was an independent prognostic factor for progression-free survival and overall survival of endometrial carcinoma;</p> <p>Conclusions</p> <p>P-LVD may serve as a prognostic factor for endometrial carcinoma. The peritumoral lymphatics might play an important role in lymphatic vessel metastasis.</p

    Search for ZZ and ZW Production in ppbar Collisions at sqrt(s) = 1.96 TeV

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    We present a search for ZZ and ZW vector boson pair production in ppbar collisions at sqrt(s) = 1.96 TeV using the leptonic decay channels ZZ --> ll nu nu, ZZ --> l l l' l' and ZW --> l l l' nu. In a data sample corresponding to an integrated luminosity of 194 pb-1 collected with the Collider Detector at Fermilab, 3 candidate events are found with an expected background of 1.0 +/- 0.2 events. We set a 95% confidence level upper limit of 15.2 pb on the cross section for ZZ plus ZW production, compared to the standard model prediction of 5.0 +/- 0.4 pb.Comment: 7 pages, 2 figures. This version is accepted for publication by Phys. Rev. D Rapid Communication

    Measurement of the Cross Section for Prompt Diphoton Production in p-pbar Collisions at sqrt(s) = 1.96 TeV

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    We report a measurement of the rate of prompt diphoton production in ppˉp\bar{p} collisions at s=1.96 TeV\sqrt{s}=1.96 ~\hbox{TeV} using a data sample of 207 pb1^{-1} collected with the upgraded Collider Detector at Fermilab (CDF II). The background from non-prompt sources is determined using a statistical method based on differences in the electromagnetic showers. The cross section is measured as a function of the diphoton mass, the transverse momentum of the diphoton system, and the azimuthal angle between the two photons and is found to be consistent with perturbative QCD predictions.Comment: 7 pages, 3 figures,revtex4. Version accepted by PRL, but with cross section tables i

    Consensus Paper: Cerebellum and Social Cognition.

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    The traditional view on the cerebellum is that it controls motor behavior. Although recent work has revealed that the cerebellum supports also nonmotor functions such as cognition and affect, only during the last 5 years it has become evident that the cerebellum also plays an important social role. This role is evident in social cognition based on interpreting goal-directed actions through the movements of individuals (social "mirroring") which is very close to its original role in motor learning, as well as in social understanding of other individuals' mental state, such as their intentions, beliefs, past behaviors, future aspirations, and personality traits (social "mentalizing"). Most of this mentalizing role is supported by the posterior cerebellum (e.g., Crus I and II). The most dominant hypothesis is that the cerebellum assists in learning and understanding social action sequences, and so facilitates social cognition by supporting optimal predictions about imminent or future social interaction and cooperation. This consensus paper brings together experts from different fields to discuss recent efforts in understanding the role of the cerebellum in social cognition, and the understanding of social behaviors and mental states by others, its effect on clinical impairments such as cerebellar ataxia and autism spectrum disorder, and how the cerebellum can become a potential target for noninvasive brain stimulation as a therapeutic intervention. We report on the most recent empirical findings and techniques for understanding and manipulating cerebellar circuits in humans. Cerebellar circuitry appears now as a key structure to elucidate social interactions
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