595 research outputs found

    Quality of ultrasound biometry obtained by local health workers in a refugee camp on the Thai-Burmese border.

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    Objective: In a refugee camp on the Thai–Burmese border, accurate dating of pregnancy relies on ultrasound measurements obtained by locally trained health workers. The aim of this study was to substantiate the accuracy of fetal biometry measurements performed by locally trained health workers by comparing derived reference equations with those published for Asian and European hospitals. Methods: This prospective observational study included 1090 women who had a dating crown–rump length (CRL) scan and one study-appointed ultrasound biometry scan between 16 and 40 weeks of gestation. The average of two measurements of each of biparietal diameter, head circumference, abdominal circumference and femur length was used in a polynomial regression model for the mean and SD against gestational age (GA). The biometry equations obtained were compared with published equations of professional sonographers from Asian and European hospitals by evaluation of the SD and Z-scores of differences between models. Results: Reference equations of biometric parameters were found to fit cubic polynomial models. The observed SD values, for any given GA, of fetal biometric measurements obtained by locally trained health workers were lower than those previously reported by centers with professional sonographers. For nearly the entire GA range considered, the mean values of the Asian and European equations for all four biometric measurements were within the 90% expected range (mean ± 1.645 SD) of our equations. Conclusion: Locally trained health workers in a refugee camp on the Thai–Burmese border can obtain measurements that are associated with low SD values and within the normal limits of published Asian and European equations. The fact that the SD values were lower than in other studies may be explained by the use of the average of two measurements, CRL dating or motivation of the locally trained sonographer

    A [4Fe-4S]-Fe(CO)(CN)-L-cysteine intermediate is the first organometallic precursor in [FeFe] hydrogenase H-cluster bioassembly.

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    Biosynthesis of the [FeFe] hydrogenase active site (the 'H-cluster') requires the interplay of multiple proteins and small molecules. Among them, the radical S-adenosylmethionine enzyme HydG, a tyrosine lyase, has been proposed to generate a complex that contains an Fe(CO)2(CN) moiety that is eventually incorporated into the H-cluster. Here we describe the characterization of an intermediate in the HydG reaction: a [4Fe-4S][(Cys)Fe(CO)(CN)] species, 'Complex A', in which a CO, a CN- and a cysteine (Cys) molecule bind to the unique 'dangler' Fe site of the auxiliary [5Fe-4S] cluster of HydG. The identification of this intermediate-the first organometallic precursor to the H-cluster-validates the previously hypothesized HydG reaction cycle and provides a basis for elucidating the biosynthetic origin of other moieties of the H-cluster

    A comparison of fresh and used aircraft oil for the identification of toxic substances linked to aerotoxic syndrome

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    Fresh and used aircraft engine lubricants (Mobil Jet Oil II) were analysed using a Fourier Transform Ion Cyclotron Resonance Mass Spectrometer (FTICRMS) and comprehensive two dimensional gas chromatography with high resolution time of flight mass spectrometry (GCxGC-HRTOFMS). The composition of the fresh oil was established, with special focus to its tricresyl phosphate (TCP) content as this has formed the focus for most investigations into aerotoxic syndrome. The results showed that only four TCP isomers were present at detectable levels in the fresh oil: mmm-TCP, mmp-TCP, ppm-TCP and ppp-TCP. The results indicate that the formulation of Mobile Jet Oil II does not contain the more toxic ortho substituted TCP isomers at concentrations above 0.0005%. The temperatures of jet engines during operation are greater than 200 °C which creates the potential to alter the composition of the original oil and create other toxic compounds. The results show there may be a significant risk from alkylated cresyl phosphates, which were identified in the used oils at concentrations calculated in the range of 0.13–0.69%. w/w. Several xylenyl and ethylphenyl phosphates have been shown to exhibit a similar toxicity to ortho substituted TCP isomers which makes there discovery in used oil significant. These compounds should be included in future aircraft air quality studies and when assessing the risks and causes of aerotoxic syndrome

    Till death (or an intruder) do us part: intrasexual-competition in a monogamous Primate

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    Polygynous animals are often highly dimorphic, and show large sex-differences in the degree of intra-sexual competition and aggression, which is associated with biased operational sex ratios (OSR). For socially monogamous, sexually monomorphic species, this relationship is less clear. Among mammals, pair-living has sometimes been assumed to imply equal OSR and low frequency, low intensity intra-sexual competition; even when high rates of intra-sexual competition and selection, in both sexes, have been theoretically predicted and described for various taxa. Owl monkeys are one of a few socially monogamous primates. Using long-term demographic and morphological data from 18 groups, we show that male and female owl monkeys experience intense intra-sexual competition and aggression from solitary floaters. Pair-mates are regularly replaced by intruding floaters (27 female and 23 male replacements in 149 group-years), with negative effects on the reproductive success of both partners. Individuals with only one partner during their life produced 25% more offspring per decade of tenure than those with two or more partners. The termination of the pair-bond is initiated by the floater, and sometimes has fatal consequences for the expelled adult. The existence of floaters and the sporadic, but intense aggression between them and residents suggest that it can be misleading to assume an equal OSR in socially monogamous species based solely on group composition. Instead, we suggest that sexual selection models must assume not equal, but flexible, context-specific, OSR in monogamous species.Wenner-Gren Foundation, L.S.B. Leakey Foundation, the National Geographic Society, National Science Foundation (BCS- 0621020), the University of Pennsylvania Research Foundation and the Zoological Society of San Diego, German Science Foundation (HU 1746-2/1

    Specific MRI Abnormalities Reveal Severe Perrault Syndrome due to CLPP Defects

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    In establishing a genetic diagnosis in heterogeneous neurological disease, clinical characterization and whole exome sequencing (WES) go hand-in-hand. Clinical data are essential, not only to guide WES variant selection and define the clinical severity of a genetic defect but also to identify other patients with defects in the same gene. In an infant patient with sensorineural hearing loss, psychomotor retardation, and epilepsy, WES resulted in identification of a novel homozygous CLPP frameshift mutation (c.21delA). Based on the gene defect and clinical symptoms, the diagnosis Perrault syndrome type 3 (PRLTS3) was established. The patient's brain-MRI revealed specific abnormalities of the subcortical and deep cerebral white matter and the middle blade of the corpus callosum, which was used to identify similar patients in the Amsterdam brain-MRI database, containing over 3000 unclassified leukoencephalopathy cases. In three unrelated patients with similar MRI abnormalities the CLPP gene was sequenced, and in two of them novel missense mutations were identified together with a large deletion that covered part of the CLPP gene on the other allele. The severe neurological and MRI abnormalities in these young patients were due to the drastic impact of the CLPP mutations, correlating with the variation in clinical manifestations among previously reported patients. Our data show that similarity in brain-MRI patterns can be used to identify novel PRLTS3 patients, especially during early disease stages, when only part of the disease manifestations are present. This seems especially applicable to the severely affected cases in which CLPP function is drastically affected and MRI abnormalities are pronounce

    Antibody-Neutralized Reovirus Is Effective in Oncolytic Virotherapy

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    Immunotherapy is showing promise for otherwise incurable cancers. Oncolytic viruses (OVs), developed as direct cytotoxic agents, mediate their antitumor effects via activation of the immune system. However, OVs also stimulate antiviral immune responses, including the induction of OV-neutralizing antibodies. Current dogma suggests that the presence of preexisting antiviral neutralizing antibodies in patients, or their development during viral therapy, is a barrier to systemic OV delivery, rendering repeat systemic treatments ineffective. However, we have found that human monocytes loaded with preformed reovirus–antibody complexes, in which the reovirus is fully neutralized, deliver functional replicative reovirus to tumor cells, resulting in tumor cell infection and lysis. This delivery mechanism is mediated, at least in part, by antibody receptors (in particular FcγRIII) that mediate uptake and internalization of the reovirus/antibody complexes by the monocytes. This finding has implications for oncolytic virotherapy and for the design of clinical OV treatment strategies

    Executive function and IQ predict mathematical and attention problems in very preterm children

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    Objective of this study was to examine the impact of executive function (EF) on mathematical and attention problems in very preterm (gestational age ≤ 30 weeks) children. Participants were 200 very preterm (mean age 8.2 ± 2.5 years) and 230 term children (mean age 8.3 ± 2.3 years) without severe disabilities, born between 1996 and 2004. EFs assessed included verbal fluency, verbal working memory, visuospatial span, planning, and impulse control. Mathematics was assessed with the Dutch Pupil Monitoring System and parents and teachers rated attention problems using standardized behavior questionnaires. The impact of EF was calculated over and above processi

    Prevalence and risk factors for HIV-1 infection in rural Kilimanjaro region of Tanzania: Implications for prevention and treatment

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    BACKGROUND: Variability in stages of the HIV-1 epidemic and hence HIV-1 prevalence exists in different areas in sub-Saharan Africa. The purpose of this study was to investigate the magnitude of HIV-1 infection and identify HIV-1 risk factors that may help to develop preventive strategies in rural Kilimanjaro, Tanzania. METHODS: A cross-sectional study was conducted between March and May of 2005 involving all individuals aged between 15–44 years having an address in Oria Village. All eligible individuals were registered and invited to participate. Participants were interviewed regarding their demographic characteristics, sexual behaviors, and medical history. Following a pre-test counseling, participants were offered an HIV test. RESULTS: Of the 2 093 eligible individuals, 1 528 (73.0%) participated. The overall age and sex adjusted HIV-1 prevalence was 5.6%. Women had 2.5 times higher prevalence (8.0% vs. 3.2%) as compared to men. The age group 25–44 years, marriage, separation and low education were associated with higher risk of HIV-1 infection for both sexes. HIV-1 infection was significantly associated with >2 sexual partners in the past 12 months (women: Adjusted odds ratio [AOR], 2.5 (95%CI: 1.3–4.7), and past 5 years, [(men: AOR, 2.2 (95%CI:1.2–5.6); women: AOR, 2.5 (95%CI: 1.4–4.0)], unprotected casual sex (men: AOR,1.8 95%CI: 1.2–5.8), bottled alcohol (Men: AOR, 5.9 (95%CI:1.7–20.1) and local brew (men: AOR, 3.7 (95%CI: 1.5–9.2). Other factors included treatment for genital ulcers and genital discharge in the past 1 month. Health-related complaints were more common among HIV-1 seropositive as compared to seronegative participants and predicted the presence of HIV-1 infection. CONCLUSION: HIV-1 infection was highly prevalent in this population. As compared to our previous findings, a shift of the epidemic from a younger to an older age group and from educated to uneducated individuals was observed. Women and married or separated individuals remained at higher risk of infection. To prevent further escalation of the HIV epidemic, efforts to scale up HIV prevention programmes addressing females, people with low education, lower age at marriage, alcohol consumption, condom use and multiple sexual partners for all age groups remains a top priority. Care and treatment are urgently needed for those infected in rural areas

    Tunable Frohlich Polarons in Organic Single-Crystal Transistors

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    In organic field effect transistors (FETs), charges move near the surface of an organic semiconductor, at the interface with a dielectric. In the past, the nature of the microscopic motion of charge carriers -that determines the device performance- has been related to the quality of the organic semiconductor. Recently, it has been appreciated that also the nearby dielectric has an unexpectedly strong influence. The mechanisms responsible for this influence are not understood. To investigate these mechanisms we have studied transport through organic single crystal FETs with different gate insulators. We find that the temperature dependence of the mobility evolves from metallic-like to insulating-like with increasing the dielectric constant of the insulator. The phenomenon is accounted for by a two-dimensional Frohlich polaron model that quantitatively describes our observations and shows that increasing the dielectric polarizability results in a crossover from the weak to the strong polaronic coupling regime
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