1,747 research outputs found

    Electrochemical cardiac troponin I immunosensor based on nitrogen and boron-doped graphene quantum dots electrode platform and Ce-doped SnO2/SnS2 signal amplification

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    The detection of acute myocardial infarction directly depends on the concentration of the cardiac troponin I (CTnI) in human blood plasma. In this study, the sensitive, selective, and fast sandwich-type electrochemical CTnI immunosensor was developed by using nitrogen and boron-dopped graphene quantum dots -as electrode platform and two-dimensional Ce-dopped SnO2/SnS2 (Ce–SnO2/SnS2) as signal amplification. In preparation of electrochemical CTnI immunosensor, the coordinated covalent bond between capture antibody (anti-CTnI-Ab1) and nitrogen and boron-dopped graphene quantum dots as electrode platform led to immobilization of anti-CTnI-Ab1, and the strong esterification between the secondary antibody (anti-CTnI-Ab2) and thioglycolic acid-modified Ce–SnO2/SnS2 resulted in anti-CTnI-Ab2 conjugation. Finally, the resultant electrochemical CTnI immunosensor was formed via antigen-antibody interaction. High-resolution transmission electron microscopy, X-ray photoelectron spectroscopy, X-ray diffraction, Fourier transform infrared spectroscopy, UV–Vis spectroscopy and Raman spectroscopy, as well as some electrochemical characterization techniques, including cyclic voltammetry, differential pulse voltammetry and electrochemical impedance spectroscopy were used to characterize the prepared immunosensor. The detection limit of CTnI in plasma samples was calculated as 2.00 fg mL−1, making it an effective tool for acute myocardial infarction testing. © 2021 Elsevier Lt

    Fixed-point realization of fast nonlinear Fourier transform algorithm for FPGA implementation of optical data processing

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    The nonlinear Fourier transform (NFT) based signal processing has attracted considerable attention as a promising tool for fibre nonlinearity mitigation in optical transmission. However, the mathematical complexity of NFT algorithms and the noticeable distinction of the latter from the “conventional” (Fourier-based) methods make it difficult to adapt this approach for practical applications. In our work, we demonstrate a hardware implementation of the fast direct NFT operation: it is used to map the optical signal onto its nonlinear Fourier spectrum, i.e. to demodulate the data. The main component of the algorithm is the matrix-multiplier unit, implemented on field-programmable gate arrays (FPGA) and used in our study for the estimation of required hardware resources. To design the best performing implementation in limited resources, we carry out the processing accuracy analysis to estimate the optimal bit width. The fast NFT algorithm that we analyse, is based on the FFT, which leads to the O(N log^{2}_{2} N) method’s complexity for the signal consisting of N samples. Our analysis revealed the significant demand in DSP blocks on the used board, which is caused by the complex-valued matrix operations and FFTs. Nevertheless, it seems to be possible to utilise further the parallelisation of our NFT-processing implementation for the more efficient NFT hardware realisation

    Age Estimation Based on Computed Tomography Analysis of the Scapula.

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    Background and Objectives: Age estimation from skeletal remains and in living individuals is an important issue for human identification, and also plays a critical role in judicial proceedings for migrants. Forensic analysis of ossification centers is the main evaluation method for age estimation, and ossification degree can be determined using computed tomography analysis. The purpose of this study is to investigate the applicability of CT (computed tomography) in the analysis of left scapula ossification centers, for forensic age estimation in Turkish society. Materials and Methods: We analyzed six ossification centers of the left scapula and these ossification centers are the coracoid, subcoracoid, coracoid apex, acromial, glenoid, and inferior angle ossification centers. A pediatric radiologist analyzed these six ossification centers of the scapula by using a staging method defined by Schmeling et al. in 2004. Two months after the first assessment, 20 randomly selected cases was reanalyzed by the first observer and by another pediatric radiologist. Correlation between the age and ossification stage was assessed using Spearman's nonparametric correlation test. Linear regression analysis was performed using a backwards model. Cohen's kappa coefficient was used for evaluating interobserver and intraobserver variability. Results: In this retrospective study, 397 (248 male and 149 female) cases were evaluated. Ages ranged between 7.1 and 30.9. The mean age was 19.83 ± 6.49. We determined a positive significant correlation between the age and the ossification stages of ossification centers analyzed in both sexes. In each ossification center, except inferior angle, all of the stage 1 and 2 cases in both sexes were under 18 years old. Intraobserver and interobserver evaluations showed that reproducibility and consistency of the method was relatively good. Conclusions: The present study indicated that CT analysis of scapula ossification centers might be helpful in forensic age assessment of living individuals and dry bones

    Ultrafast Hot-Carrier Dynamics in Ultrathin Monocrystalline Gold

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    Applications in photodetection, photochemistry, and active metamaterials and metasurfaces require fundamental understanding of ultrafast nonthermal and thermal electron processes in metallic nanosystems. Significant progress has been recently achieved in synthesis and investigation of low-loss monocrystalline gold, opening up opportunities for its use in ultrathin nanophotonic architectures. Here, we reveal fundamental differences in hot-electron thermalisation dynamics between monocrystalline and polycrystalline ultrathin (down to 10 nm thickness) gold films. Comparison of weak and strong excitation regimes showcases a counterintuitive unique interplay between thermalised and non-thermalised electron dynamics in mesoscopic gold with the important influence of the X-point interband transitions on the intraband electron relaxation. We also experimentally demonstrate the effect of hot-electron transfer into a substrate and the substrate thermal properties on electron-electron and electron-phonon scattering in ultrathin films. The hot-electron injection efficiency from monocrystalline gold into TiO2, approaching 9% is measured, close to the theoretical limit. These experimental and modelling results reveal the important role of crystallinity and interfaces on the microscopic electronic processes important in numerous applications.Comment: 9 pages, 4 figure

    Generalized reactive amyloidosis in a gazelle (gazella gazella)

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    Bu raporda 1.5 yaşında, erkek bir dağ ceylanında saptanan generalize reaktif amiloidozis tanımlandı. Makroskobik incelemede karın boşluğundaki serozalarda hiperemi ve rumende ise kenarları kanamalı 7 cm çapında ülser belirlendi. Her iki böbreğin yüzeyinde 1-2 mm büyüklüğünde boz-beyaz renkte odaklar gözlendi. Mikroskobik incelemelerde böbreklerde glomerulus, tubulus ve akıtıcı kanal bazal membranları ve damar duvarlarında, dalakta foliküllerde, karaciğerde Disse aralığında ve ince barsaklarda lamina propriyada pembe renkte, homojen ve amorf yapıda birikimler gözlendi. Bu birikimlerin Kongo kırmızısı ile tuğla kırmızısı renkte boyandıkları, potasyum permanganat ile muamele edildikten sonra Kongo kırmızısı ile boyanmadıkları görülerek AA-amiloidoz (sekonder amiloidozis) olduğu kanısına varıldı. %10"luk formaldehitte bulunan stok doku parçalarının Lugol ve sülfirik asitle muamele edilmeleri sonucunda amiloid birikimlerinin koyu mavi renkte oldukları gözlendi. Rumende ülserasyonla birlikte generalize amiloidoz saptanan bu olguda, amiloid birikimlerinin makroskobik olarak sadece taze dokularda değil formaldehit solüsyonunda tespit edildikten sonra da gösterilebileceğine dikkat çekilmiştir

    Interfacial Hot Carrier Collection Controls Plasmonic Chemistry

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    Harnessing non-equilibrium hot carriers from plasmonic metal nanostructures constitutes a vibrant research field. It promises to enable control of activity and selectivity of photochemical reactions, especially for solar fuel generation. However, a comprehensive understanding of the interplay of plasmonic hot carrier-driven processes in metal/semiconducting heterostructures has remained elusive. In this work, we reveal the complex interdependence between plasmon excitation, hot carrier generation, transport and interfacial collection in plasmonic photocatalytic devices, uniquely determining the charge injection efficiencies at the solid/solid and solid/liquid interfaces. Interestingly, by measuring the internal quantum efficiency of ultrathin (14 to 33 nm) single-crystalline plasmonic gold (Au) nanoantenna arrays on titanium dioxide substrates, we find that the performance of the device is governed by hot hole collection at the metal/electrolyte interface. In particular, by combining a solid- and liquid-state experimental approach with ab initio simulations, we show a more efficient collection of high-energy d-band holes traveling in [111] orientation, resulting in a stronger oxidation reaction at the {111} surfaces of the nanoantenna. These results thus establish new guidelines for the design and optimization of plasmonic photocatalytic systems and optoelectronic devices

    Effect of simulated gastric acid on aesthetical restorative CAD-CAM materials' microhardness and flexural strength

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    Background: Gastric acid, which is among erosive substances, gradually rises to the mouth in individuals with reflux and bulimia nervosa disorders, and this causes various effects on dental restorations. Aim: The objective of this study is in vitro investigation of gastric acid's effect on flexural strength and hardness on aesthetic restorative computer-aided design and computer-aided manufacturing (CAD-CAM) materials. Materials and Methods: For this study, four materials have been used, namely Enamic (Vita), Superfect Zir (Aidite) Zirconia, IPS e.max CAD (Ivoclar Vivadent), and Mark II (Vita). From these four different materials, 24 samples with 14 × 4 × 1 dimensions in rectangular prism form are used, which makes a total of 96 samples. One group was separated as the control group, while the rest was allowed to wait at 37°C, 5 ml gastric acid for 96 hours. Hardness value and flexural strengths were measured as pre-exposure and post-exposure to gastric acid. Results: There is a statistically significant difference between the groups in terms of the amount of decrease in the mean hardness after exposure to gastric acid compared to pre-exposure values (p: 0,000; P 0.05). There is a statistically significant difference between the groups in terms of the average flexural strength after exposure to the acid. Conclusions: According to the data obtained, it was concluded that exposure to gastric acid affects the hardness and flexural strength properties of dental restorative ceramic materials

    In vitro Radioprotective Activity of the Bryozoan Hyalinella punctata

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    The objective of the present study was in vitro evaluation of radioprotective activity of the freshwater bryozoan Hyalinella punctata on cultured human peripheral blood lymphocytes after irradiation with 2 gy of Co-60 gamma-rays. Since its water extract at concentration 0.001 mg/mL reduced the incidence of radiation-induced micronuclei for almost 30 %, it could be considered as a promising source of new natural products with the aforementined activity. Both the content of sulphur (1.17%) determined by gravimetric method and infrared absorption frequences (76 % similarity with those of bacitracin) of the investigated extract indicate the presence of organic sulphur compound(s) such as cyclic peptides and polypeptides which might be responsible for the observed radioprotectio
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