754 research outputs found

    Ultrastructural and Molecular Changes in the Developing Small Intestine of the Toad Bufo regularis

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    The ontogenetic development of the small intestine of the toad Bufo regularis was investigated using twofold approaches, namely, ultrastructural and molecular. The former has been done using transmission electron microscope and utilizing the developmental stages 42, 50, 55, 60, 63, and 66. The most prominent ultrastructural changes were recorded at stage 60 and were more evident at stage 63. These included the appearance of apoptotic bodies/nuclei within the larval epithelium, the presence of macrophages, swollen mitochondria, distorted rough endoplasmic reticulum, chromatin condensation, and irregular nuclear envelop, and the presence of large vacuoles and lysosomes. The molecular investigation involved examining DNA content and fragmentation. The results showed that the DNA content decreased significantly during the metamorphic stages 60 and 63 compared with both larval (50 and 55) and postmetamorphic (66) stages. The metamorphic stages (60 and 63) displayed extensive DNA laddering compared with stages 50, 55, and 66. The percentage of DNA damage was 0.00%, 12.91%, 57.26%, 45.48%, and 4.43% for the developmental stages 50, 55, 60, 63, and 66, respectively. In conclusion, the recorded remodeling of the small intestine represents a model for clarifying the mechanism whereby cell death and proliferation are controlled

    Delocalized states in three-terminal superconductor-semiconductor nanowire devices

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    We fabricate three-terminal hybrid devices with a nanowire segment proximitized by a superconductor, and with two tunnel probe contacts on either side of that segment. We perform simultaneous tunneling measurements on both sides. We identify some states as delocalized above-gap states observed on both ends, and some states as localized near one of the tunnel barriers. Delocalized states can be traced from zero to finite magnetic fields beyond 0.5 T. In the parameter regime of delocalized states, we search for correlated subgap resonances required by the Majorana zero mode hypothesis. While both sides exhibit ubiquitous low-energy features at high fields, no correlation is inferred. Simulations using a one-dimensional effective model suggest that delocalized states may belong to lower one-dimensional subbands, while the localized states originate from higher subbands. To avoid localization in higher subbands, disorder may need to be further reduced to realize Majorana zero modes.Comment: Original data available at https://zenodo.org/record/395824

    A Simplified 8 × 8 Transformation And Quantization Real-Time Ip-Block For MPEG-4 H.264/AVC Applications: A New Design Flow Approach

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    Current multimedia design processes suffer from the excessively large time spent on testing new IP-blocks with references based on large video encoders specifications (usually several thousands lines of code). The appropriate testing of a single IP-block may require the conversion of the overall encoder from software to hardware, which is difficult to complete in the short time required by the competition-driven reduced time-to-market demanded for the adoption of a new video coding standard. This paper presents a new design flow to accelerate the conformance testing of an IP-block using the H.264/AVC software reference model. An example block of the simplified 8 × 8 transformation and quantization, which is adopted in FRExt, is provided as a case study demonstrating the effectiveness of the approach

    Non-linear adsorption characteristics of modified pine wood sawdust optimised for adsorption of Cd(II) from aqueous systems

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    A chemically-modified adsorbent (SDTMA), produced from the treatment of pinewood sawdust with maleic acid, was tested in batch adsorption experiments to remove Cd(II) ions from aqueous solution. SDTMA was characterised for the pH of zero point charge (pHZPC), spectroscopic evaluation of the surface functionalisation, structural and morphological features. Factors affecting adsorption behaviour, such as adsorbent dose, pH of solution, contact time and Cd(II) ion concentration were investigated. Results obtained show that adsorption rate to be comparatively fast, with equilibrium achieved after ~35 min. Subsequent analysis, showed Langmuirian behaviour and a monolayer adsorption capacity of 180.4 mg g-1, at pH 6; while data derived from two-parameter (Langmuir, Freundlich, Temkin and Dubinin-Radushkevich (D-R)) and three-parameter (Redlich-Peterson (R-P), Toth Khan and Sips) isotherm models was evaluated using non-linear regression methods, with error analysis, to determine the most appropriate model and allow prediction of optimum parameters. The Sips isotherm model proved the most appropriate in describing the experimental data obtained in the study. Additionally, the rate of adsorption was analysed using a range of kinetic models (pseudo-first-order, pseudo-second-order, intra-particle diffusion, Bangham and Elovich) in their non-linear forms to provide insight into the adsorption mechanism and showing pseudo-second order behaviour is observed. In conclusion, the SDTMA adsorbent material produced in this study offers high potential for the removal of Cd(II) ions from aqueous solution due to the carboxylic functionalities incorporated into the material, which is optimised by solution pH and adsorbent dose

    Motor system hyperconnectivity in juvenile myoclonic epilepsy: a cognitive functional magnetic resonance imaging study

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    Juvenile myoclonic epilepsy is the most frequent idiopathic generalized epilepsy syndrome. It is characterized by predominant myoclonic jerks of upper limbs, often provoked by cognitive activities, and typically responsive to treatment with sodium valproate. Neurophysiological, neuropsychological and imaging studies in juvenile myoclonic epilepsy have consistently pointed towards subtle abnormalities in the medial frontal lobes. Using functional magnetic resonance imaging with an executive frontal lobe paradigm, we investigated cortical activation patterns and interaction between cortical regions in 30 patients with juvenile myoclonic epilepsy and 26 healthy controls. With increasing cognitive demand, patients showed increasing coactivation of the primary motor cortex and supplementary motor area. This effect was stronger in patients still suffering from seizures, and was not seen in healthy controls. Patients with juvenile myoclonic epilepsy showed increased functional connectivity between the motor system and frontoparietal cognitive networks. Furthermore, we found impaired deactivation of the default mode network during cognitive tasks with persistent activation in medial frontal and central regions in patients. Coactivation in the motor cortex and supplementary motor area with increasing cognitive load and increased functional coupling between the motor system and cognitive networks provide an explanation how cognitive effort can cause myoclonic jerks in juvenile myoclonic epilepsy. The supplementary motor area represents the anatomical link between these two functional systems, and our findings may be the functional correlate of previously described structural abnormalities in the medial frontal lobe in juvenile myoclonic epilepsy

    Single session endoscopic management of intrinsic ureteropelvic junction obstruction and concomitant renal stone disease in a child: a case report

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    BACKGROUND: Percutaneous nephrolithotomy is a well known therapeutic modality for stone diseases of childhood. Antegrade and retrograde endopyelotomies are also well defined options of treatment for secondary ureteropelvic junction obstruction. Yet there are few reports regarding endoscopic therapy of intrinsic ureteropelvic junction obstruction. To our knowledge, there exist only a few reports of endosurgical treatment of children with stone disease and with concomitant intrinsic ureteropelvic junction obstruction, in the literature. CASE PRESENTATION: We present the endoscopic management of stone disease and concomitant intrinsic ureteropelvic junction obstruction of a child in one session. CONCLUSION: Percutaneous nephrolithotomy and antegrade endopyelotomy is combined safely with successful outcome in a child
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