5,642 research outputs found

    PIERCE1 is critical for specification of left-right asymmetry in mice.

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    The specification of left-right asymmetry of the visceral organs is precisely regulated. The earliest breakage of left-right symmetry occurs as the result of leftward flow generated by asymmetric beating of nodal cilia, which eventually induces asymmetric Nodal/Lefty/Pitx2 expression on the left side of the lateral plate mesoderm. PIERCE1 has been identified as a p53 target gene involved in the DNA damage response. In this study, we found that Pierce1-null mice exhibit severe laterality defects, including situs inversus totalis and heterotaxy with randomized situs and left and right isomerisms. The spectrum of laterality defects was closely correlated with randomized expression of Nodal and its downstream genes, Lefty1/2 and Pitx2. The phenotype of Pierce1-null mice most closely resembled that of mutant mice with impaired ciliogenesis and/or ciliary motility of the node. We also found the loss of asymmetric expression of Cerl2, the earliest flow-responding gene in the node of Pierce1-null embryos. The results suggest that Pierce1-null embryos have defects in generating a symmetry breaking signal including leftward nodal flow. This is the first report implicating a role for PIERCE1 in the symmetry-breaking step of left-right asymmetry specification.1110Ysciescopu

    Зональные фораминиферовые схемы нижнего карбона западных регионов Украины

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    Запропоновано зональні форамініферові схеми нижнього карбону Придобруджинського прогину та Львівсько-Волинського басейну. У Придобруджинському прогині нараховується вісім зон і дві підзони, з них одна зона і дві підзони виділені вперше. У п'яти зон змінено види-індекси, У Львівсько-Волинському басейні є п’ять зон і дві підзони, з них одна зона нова. Дві колишні зони об'єднано в одну — з двома підзонами. Змінено види-індекси трьох зон. В обох регіонах уточнено обсяг зон та їх межі. Границі зон і підзон проведено за першою появою видів-індексів. Проведено зіставлення цих зональних схем із форамініферовими зонами Доно-Дніпровського регіону і Східно-Європейської платформи.Foraminiferal zonal schemes of the Lower Carboniferous of the Dobrudja Foredeep and Lvov-Volynian basin are proposed in the paper. The first scheme includes eight zones and two subzones; among them one zone and two subzones are specified for the first time. In five zones species-index is changed. The second scheme includes five zones and two subzones; one zone is specified for the first time. Two preceding zones are united into one with two subzones. In three zones species-index is changed. The boundaries of zones and subzones are determined according to the first occurrence of species-index. Correlation of these zones with foraminiferal zones of Dono-Dnieper region and East-European platform is performed

    VIABILITY, FATTY ACID COMPOSITION, AND STRUCTURE OF THE CORALLINE ALGA CORALLINA PILULIFERA

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    The decrease in the seaweed flora in some rocky areas, known as algal whitening or barren ground, is associated with some species of coralline algae. To determine the biological characteristics of a representative species of branched coralline alga, the number of medullary tiers was counted and ranged from 12 to 16. The 18S rDNA, psbA, and rbcL genes were used to confirm the identification of Corallina pilulifera. Measuring viability using triphenyl tetrazolium chloride showed highly viability from December to January. Cultural conditions of 16 C, 16 h light:8 h dark cycle, and 40 mu E m(-2) s(-1) light intensity were optimal for maintaining the viability of the coralline alga for up to three days. The fatty acids included 31.4% omega-3 eicosapentaenoic acid. Scanning electron microscopy of the surface structure revealed unique round wells about 7.9 +/- 1.3 mu m in diameter. The coralline alga, preventing fleshy seaweeds, may be used as a potential template for the creation of new environmentally friendly biomimetic antifouling material against the attachment of soft foulants, especially micro- and macroalgae.X111Ysciescopu

    Genetic contributions to stability and change in intelligence from childhood to old age

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    Understanding the determinants of healthy mental ageing is a priority for society today1,2. So far, we know that intelligence differences show high stability from childhood to old age3,4 and there are estimates of the genetic contribution to intelligence at different ages5,6. However, attempts to discover whether genetic causes contribute to differences in cognitive ageing have been relatively uninformative7–10. Here we provide an estimate of the genetic and environmental contributions to stability and change in intelligence across most of the human lifetime. We used genome-wide single nucleotide polymorphism (SNP) data from 1,940 unrelated individuals whose intelligence was measured in childhood (age 11 years) and again in old age (age 65, 70 or 79 years)11,12. We use a statistical method that allows genetic (co)variance to be estimated from SNP data on unrelated individuals13–17. We estimate that causal genetic variants in linkage disequilibrium with common SNPs account for 0.24 of the variation in cognitive ability change from childhood to old age. Using bivariate analysis, we estimate a genetic correlation between intelligence at age 11 years and in old age of 0.62. These estimates, derived from rarely available data on lifetime cognitive measures, warrant the search for genetic causes of cognitive stability and change

    Structural insights into RNA processing by the human RISC-loading complex.

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    Targeted gene silencing by RNA interference (RNAi) requires loading of a short guide RNA (small interfering RNA (siRNA) or microRNA (miRNA)) onto an Argonaute protein to form the functional center of an RNA-induced silencing complex (RISC). In humans, Argonaute2 (AGO2) assembles with the guide RNA-generating enzyme Dicer and the RNA-binding protein TRBP to form a RISC-loading complex (RLC), which is necessary for efficient transfer of nascent siRNAs and miRNAs from Dicer to AGO2. Here, using single-particle EM analysis, we show that human Dicer has an L-shaped structure. The RLC Dicer's N-terminal DExH/D domain, located in a short 'base branch', interacts with TRBP, whereas its C-terminal catalytic domains in the main body are proximal to AGO2. A model generated by docking the available atomic structures of Dicer and Argonaute homologs into the RLC reconstruction suggests a mechanism for siRNA transfer from Dicer to AGO2

    Influence of prohexadione-calcium, trinexapac-ethyl and hexaconazole on lodging characteristic and gibberellin biosynthesis of rice (Oryza sativa L.)

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    We investigated the influence of prohexadione-calcium (Pro-Ca), trinexapac-ethyl (TNE) and hexaconazole (HX) on lodging and gibberellin (GA) biosynthesis pathway of rice cultivar, Hwayeongbyeo. It was observed that these novel synthetic growth retardants suppressed lodging of rice under field conditions through blocking GA biosynthesis pathway. These growth retarding chemicals were applied at basic (20 uM) and elevated (40 uM) rates either 10 days before heading (10 DBH) or 5 days before heading (5 DBH). We found that Pro-Ca, TNE and their combined application (Pro-Ca + TNE) were most effective in decreasing rice length and lodging index, when applied at 10 DBH. Similarly, the endogenous bioactive GA1 contents of rice significantly declined with application of Pro-Ca, TNE and Pro-Ca + TNE, while they were less effected by basic and elevated rates of HX as compared to the control. The growth retardants were more effective in decreasing rice lodging and blocking GA biosynthesis when applied in elevated rates. The levels of the endogenous gibberellins in rice shoots were measured by GC/MS-SIM using 2H2-labeled gibberellins as internal standards. Effect of these synthetic chemicals on growth and GA inhibition were stronger initially but eroded rapidly under field conditions. It was thus concluded that Pro-Ca and TNE were most effective in reducing plant length and suppressing lodging of rice crop under field conditions, where lodging is a major constraint to higher productivity.Key words: Growth retardants, plant growth, gibberellin biosynthesis, lodging index, rice

    The wavelet-NARMAX representation : a hybrid model structure combining polynomial models with multiresolution wavelet decompositions

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    A new hybrid model structure combing polynomial models with multiresolution wavelet decompositions is introduced for nonlinear system identification. Polynomial models play an important role in approximation theory, and have been extensively used in linear and nonlinear system identification. Wavelet decompositions, in which the basis functions have the property of localization in both time and frequency, outperform many other approximation schemes and offer a flexible solution for approximating arbitrary functions. Although wavelet representations can approximate even severe nonlinearities in a given signal very well, the advantage of these representations can be lost when wavelets are used to capture linear or low-order nonlinear behaviour in a signal. In order to sufficiently utilise the global property of polynomials and the local property of wavelet representations simultaneously, in this study polynomial models and wavelet decompositions are combined together in a parallel structure to represent nonlinear input-output systems. As a special form of the NARMAX model, this hybrid model structure will be referred to as the WAvelet-NARMAX model, or simply WANARMAX. Generally, such a WANARMAX representation for an input-output system might involve a large number of basis functions and therefore a great number of model terms. Experience reveals that only a small number of these model terms are significant to the system output. A new fast orthogonal least squares algorithm, called the matching pursuit orthogonal least squares (MPOLS) algorithm, is also introduced in this study to determine which terms should be included in the final model

    Audit of the change in the on-call practices in neuroradiology and factors affecting it

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    BACKGROUND: On call practices had recently changed at the Newcastle General Hospital to accommodate increasing CT scan requests and reduce the workloads of the radiologists. In the new system, the person responsible for dealing with the out of hours requests for imaging changed from the neuroradiologist to the neuroradiographer. This audit was conducted to assess any change in the departmental workload as a result of this change. METHODS: The audit was carried out over a period of six months and data was collected from the on-call booklets which the neuroradiographers maintained and the log books maintained in the department of neuroradiology. Details of the imaging requested; the source of the request, the reason for the request and the results of the scans were recorded and analysed using Microsoft Excel™. RESULTS: The number of CT scans requested from the A&E went up by 73.4% after the change in practice and majority of these increases were due to increased requests for scans on head injuries which increased by 122%. Although this was not statistically significant due to lack of study power, it is clinically relevant. CONCLUSION: The increase in the number of CT scans for head injuries reflects a general change in practice in management of head injuries in the UK. Changing the gatekeeper from radiologist to radiographer was associated with an increase in CT rate, particularly for head injuries. Other factors such as clinician seniority and a greater awareness of the NICE guidelines may have also contributed

    Composite magnetostrictive materials for advanced automotive magnetomechanical sensors

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    In this paper we present the development of a composite magnetostrictive material for automotive applications. The material is based on cobaltferrite,CoO⋅Fe2O3, and contains a small fraction of metallic matrix phase that serves both as a liquid-phasesintering aid during processing and enhances the mechanical properties over those of a simple sinteredferrite ceramic. In addition the metal matrix makes it possible to braze the material, making the assembly of a sensor relatively simple. The material exhibits good sensitivity and should have high corrosion resistance, while at the same time it is low in cost
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