435 research outputs found

    Does low-dose aspirin reduce preeclampsia and other maternal-fetal complications?

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    The use of low-dose aspirin during pregnancy decreases the risk of preeclampsia for women considered at increased risk. The effect is smaller for women without risk factors (strength of recommendation [SOR]: A, based on randomized controlled trials [RCTs] and systematic reviews [SRs] of RCTs)

    Ureteral calculi: What should you consider before intervening?

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    The size of the calculi, their location, and complicating factors such as infection should all be considered. Most ureteral calculi smaller than 5 mm pass spontaneously, as do approximately half of calculi between 5 and 10 mm. Calculi larger than 10 mm are unlikely to pass without intervention. Distal calculi are more likely to pass spontaneously than calculi in mid- or proximal ureteral locations; most spontaneous passage occurs within 4 to 6 weeks (strength of recommendation [SOR]: A, prospective cohort studies). All patients with calculi complicated by such factors as obstruction, infection, renal injury, or a single kidney require surgical consultation (SOR: C, expert opinion). Medical expulsion therapy with alpha-blockers (usually tamsulosin) and nifedipine improves passage rates, including for some calculi larger than 10 mm (SOR: A, metaanalysis of prospective cohort studies)

    Shell structure and electron-electron interaction in self-assembled InAs quantum dots

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    Using far-infrared spectroscopy, we investigate the excitations of self-organized InAs quantum dots as a function of the electron number per dot, 1<n<6, which is monitored in situ by capacitance spectroscopy. Whereas the well-known two-mode spectrum is observed when the lowest s - states are filled, we find a rich excitation spectrum for n=3, which reflects the importance of electron-electron interaction in the present, strongly non-parabolic confining potential. From capacitance spectroscopy we find that the electronic shell structure in our dots gives rise to a distinct pattern in the charging energies which strongly deviates from the monotonic behavior of the Coulomb blockade found in mesoscopic or metallic structures.Comment: 4 pages, 3 PostScript figure

    Fibrinogen αC‐regions are not directly involved in fibrin polymerization as evidenced by a "Double‐Detroit" recombinant fibrinogen mutant and knobs‐mimic peptides

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    Background: Fibrin polymerization, following fibrinopeptides A and B (FpA, FpB) cleavage, relies on newly exposed α‐ and ÎČ‐chains N‐termini (GPR, GHR; A‐, B‐knobs, respectively) engaging pre‐existent a and b pockets in other fibrin(ogen) molecules' γ‐ and (B)ÎČ‐chains C‐terminal regions. A role for mostly disordered (A)α‐chains C‐terminal regions "bridging" between fibrin molecules/fibrils has been proposed. Objectives: Fibrinogen Detroit is a clinically observed mutation (AαR19→S) with non‐engaging GPS A‐knobs. By analogy, a similar BÎČ‐chain mutation, BÎČR17→S, should produce non‐engaging GHS B‐knobs. A homozygous “Double‐Detroit” mutant (AαR19→S, BÎČR17→S; DD‐FG) was developed: with A‐a and B‐b engagements endogenously blocked, other interactions would become apparent. Methods: DD‐FG, wild‐type recombinant (WT‐FG), and human plasma (hp‐FG) fibrinogen self‐association was studied by turbidimetry coupled with fibrinopeptides release HPLC/mass spectrometry analyses, and by light‐scattering following size‐exclusion chromatography (SE‐HPLC). Results: In contrast to WT‐FG and hp‐FG, DD‐FG produced no turbidity increase, irrespective of thrombin concentration. The SE‐HPLC profile of concentrated DD‐FG was unaffected by thrombin treatment, and light‐scattering, at lower concentration, showed no intensity and hydrodynamic radius changes. Compared with hp‐FG, both WT‐FG and DD‐FG showed no FpA cleavage difference, while ~50% FpB was not recovered. Correspondingly, SDS‐PAGE/Western‐blots revealed partial BÎČ‐chain N‐terminal and Aα‐chain C‐terminal degradation. Nevertheless, ~70% DD‐FG molecules bearing (A)αC‐regions potentially able to associate were available. Higher‐concentration, nearly‐intact hp‐FG with 500‐fold molar excess GPRP‐NH2/GHRP‐NH2 knobs‐mimics experiments confirmed these no‐associations findings. Conclusions: (A)αC‐regions interactions appear too weak to assist native fibrin polymerization, at least without knobs engagement. Their role in all stages should be carefully reconsidered

    Fidedignidade da versĂŁo em portuguĂȘs do InventĂĄrio de Ansiedade e Fobia Social (SPAI) em amostra heterogĂȘnea de estudantes universitĂĄrios brasileiros

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    Objetivo: Avaliar consistĂȘncia interna e estabilidade temporal, atravĂ©s de fidedignidade teste-reteste, da versĂŁo em portuguĂȘs do InventĂĄrio de Ansiedade e Fobia Social (SPAI), em uma amostra brasileira heterogĂȘnea. MĂ©todos: ApĂłs consentimento informado, a versĂŁo traduzida e adaptada para o portuguĂȘs do SPAI foi testada e re-testada, com 14 dias de intervalo, em uma amostra de 225 estudantes universitĂĄrios de ambos os gĂȘneros, de quatro cursos de graduação. ApĂłs dupla entrada de dados, a anĂĄlise estatĂ­stica incluiu Alfa de Cronbach e os coeficientes de correlação de Pearson e Intra-classe. Resultados: A amostra estudada consistiu de 213 estudantes de quatro sub-amostras: 95 estudantes de Direito, 31 de Comunicação Social, 54 de Engenharia Civil e 33 de Odontologia. A mĂ©dia de idade foi de 23 anos (± 6) e 110 (51,6%) eram do gĂȘnero feminino. O Alpha de Cronbach foi de 0,96, sem diferenças entre os gĂȘneros. O escore diferencial (total) do SPAI portuguĂȘs apresentou coeficiente de Pearson de 0,83 (IC95% 0,78-0,87) e coeficiente Intra-classe de 0,83 (IC95% 0,78-0,86). NĂŁo houve diferença estatĂ­stica nos coeficientes de Pearson entre os gĂȘneros (p = 0,121) ou entre as quatro sub-amostras (p = 0,258). ConclusĂŁo: Os resultados nĂŁo asseguram validade; a versĂŁo do SPAI portuguĂȘs apresentou boa homogeneidade de conteĂșdo com nĂ­vel satisfatĂłrio consistĂȘncia interna. A estabilidade temporal avaliada foi consistente. Os dados demonstram que o SPAI portuguĂȘs apresenta fidedignidade perfeitamente aceitĂĄvel para ambos os gĂȘneros e sugerem sua utilização na população brasileira.Objective: Tto evaluate internal consistency and temporal stability trough test re-test reliability of the Portuguese version of the Social Phobia and Anxiety Inventory (SPAI) in a heterogeneous Brazilian sample. Methods: After informed consent, the translated and adapted version of the SPAI Portuguese was tested and re-tested at a 14-day interval in a sample of 225 university students, both genders, from 4 different undergraduate courses. After double data entry, statistical analysis included Cronbach’s alphas, Pearson and intra-class correlation coefficients. Results: The studied sample consisted of 213 students from 4 sub-samples: 95 law students, 31 social communication students, 54 civil engineering students and 33 dental medicine students. The mean age was 23 (±6) years and 110 (51.6%) were female. The Cronbach’ alpha was 0.96, no difference for both genders. The differential (total) score of the SPAI Portuguese showed Pearson coefficient 0.83 (95% CI 0.78-0.87) and Intra-class coefficient 0.83 (95% CI 0.78-0.86). There was no statistical difference in Pearson coefficients between genders (p = 0.121) and the 4 sub-samples (p = 0.258). Conclusion: The results do not ensure validity, however, the SPAI Portuguese version presented a good content homogeneity with satisfactory level of internal consistency. The temporal stability evaluated was substantial. The results showed that the Portuguese SPAI presents perfectly acceptable reliability for both genders and suggest that it can be used in Brazilian population

    Zero-field spin splitting in InAs-AlSb quantum wells revisited

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    We present magnetotransport experiments on high-quality InAs-AlSb quantum wells that show a perfectly clean single-period Shubnikov-de Haas oscillation down to very low magnetic fields. In contrast to theoretical expectations based on an asymmetry induced zero-field spin splitting, no beating effect is observed. The carrier density has been changed by the persistent photo conductivity effect as well as via the application of hydrostatic pressure in order to influence the electric field at the interface of the electron gas. Still no indication of spin splitting at zero magnetic field was observed in spite of highly resolved Shubnikov- de Haas oscillations up to filling factors of 200. This surprising and unexpected result is discussed in view of other recently published data.Comment: 4 pages, 3 figures, submitted to Phys. Rev.

    Thyroid hormone receptors are required for the melatonin-dependent control of Rfrp gene expression in mice.

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    Mammals adapt to seasons using a neuroendocrine calendar defined by the photoperiodic change in the nighttime melatonin production. Under short photoperiod, melatonin inhibits the pars tuberalis production of TSHÎČ, which, in turn, acts on tanycytes to regulate the deiodinase 2/3 balance resulting in a finely tuned seasonal control of the intra-hypothalamic thyroid hormone T3. Despite the pivotal role of this T3 signaling for synchronizing reproduction with the seasons, T3 cellular targets remain unknown. One candidate is a population of hypothalamic neurons expressing Rfrp, the gene encoding the RFRP-3 peptide, thought to be integral for modulating rodent's seasonal reproduction. Here we show that nighttime melatonin supplementation in the drinking water of melatonin-deficient C57BL/6J mice mimics photoperiodic variations in the expression of the genes Tshb, Dio2, Dio3, and Rfrp, as observed in melatonin-proficient mammals. Notably, we report that this melatonin regulation of Rfrp expression is no longer observed in mice carrying a global mutation of the T3 receptor, TRα, but is conserved in mice with a selective neuronal mutation of TRα. In line with this observation, we find that TRα is widely expressed in the tanycytes. Altogether, our data demonstrate that the melatonin-driven T3 signal regulates RFRP-3 neurons through non-neuronal, possibly tanycytic, TRα.journal article2020 Aug 102020 08 10importe

    Quantitative trait loci conferring grain mineral nutrient concentrations in durum wheat 3 wild emmer wheat RIL population

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    Mineral nutrient malnutrition, and particularly deficiency in zinc and iron, afflicts over 3 billion people worldwide. Wild emmer wheat, Triticum turgidum ssp. dicoccoides, genepool harbors a rich allelic repertoire for mineral nutrients in the grain. The genetic and physiological basis of grain protein, micronutrients (zinc, iron, copper and manganese) and macronutrients (calcium, magnesium, potassium, phosphorus and sulfur) concentration was studied in tetraploid wheat population of 152 recombinant inbred lines (RILs), derived from a cross between durum wheat (cv. Langdon) and wild emmer (accession G18-16). Wide genetic variation was found among the RILs for all grain minerals, with considerable transgressive effect. A total of 82 QTLs were mapped for 10 minerals with LOD score range of 3.2–16.7. Most QTLs were in favor of the wild allele (50 QTLs). Fourteen pairs of QTLs for the same trait were mapped to seemingly homoeologous positions, reflecting synteny between the A and B genomes. Significant positive correlation was found between grain protein concentration (GPC), Zn, Fe and Cu, which was supported by significant overlap between the respective QTLs, suggesting common physiological and/or genetic factors controlling the concentrations of these mineral nutrients. Few genomic regions (chromosomes 2A, 5A, 6B and 7A) were found to harbor clusters of QTLs for GPC and other nutrients. These identified QTLs may facilitate the use of wild alleles for improving grain nutritional quality of elite wheat cultivars, especially in terms of protein, Zn and Fe

    Comparing approaches for numerical modelling of tsunami generation by deformable submarine slides

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    Tsunami generated by submarine slides are arguably an under-considered risk in comparison to earthquake-generated tsunami. Numerical simulations of submarine slide-generated waves can be used to identify the important factors in determining wave characteristics. Here we use Fluidity, an open source finite element code, to simulate waves generated by deformable submarine slides. Fluidity uses flexible unstructured meshes combined with adaptivity which alters the mesh topology and resolution based on the simulation state, focussing or reducing resolution, when and where it is required. Fluidity also allows a number of different numerical approaches to be taken to simulate submarine slide deformation, free-surface representation, and wave generation within the same numerical framework. In this work we use a multi-material approach, considering either two materials (slide and water with a free surface) or three materials (slide, water and air), as well as a sediment model (sediment, water and free surface) approach. In all cases the slide is treated as a viscous fluid. Our results are shown to be consistent with laboratory experiments using a deformable submarine slide, and demonstrate good agreement when compared with other numerical models. The three different approaches for simulating submarine slide dynamics and tsunami wave generation produce similar waveforms and slide deformation geometries. However, each has its own merits depending on the application. Mesh adaptivity is shown to be able to reduce the computational cost without compromising the accuracy of results
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