Tributyltin-induced oxidative stress causes developmental damage in the cardiovascular system of zebrafish (Danio rerio).

Tributyltin (TBT) can be used as an antifouling agent with anticorrosive, antiseptic and antifungal properties and is widely used in wood preservation and ship painting. However, it has recently been found that TBT can be harmful to aquatic organisms. In this study, to gain insight into the effects of TBT with respect to the development of the cardiovascular system in zebrafish embryos, zebrafish embryos were exposed to different concentrations of TBT solutions (0.2 µg/L, 1 µg/L, and 2 µg/L) at 2 h post-fertilization (hpf) TBT exposure resulted in decreased hatchability and heart rate, deformed features such as pericardial edema, yolk sac edema, and spinal curvature in zebrafish embryos, and impaired heart development. Expression of cardiac development-related genes (vmhc, myh6, nkx2.5, tbx5a, gata4, tbx2b, nppa) is dysregulated. Transgenic zebrafish Tg (fli1: EGFP) were used to explore the effects of TBT exposure on vascular development. It was found that TBT exposure could lead to impaired development of intersegmental vessels (ISVs), common cardinal vein (CCV), subintestinal vessels (SIVs) and cerebrovascular. The expression of vascular endothelial growth factor (VEGF) signaling pathway-related genes (flt1, flt4, kdr, vegfa) was downregulated. Biochemical indices showed that ROS and MDA levels were significantly elevated and that SOD and CAT activities were significantly reduced. The expression of key genes for prostacyclin synthesis (pla2, ptgs2a, ptgs2b, ptgis, ptgs1) is abnormal. Therefore, it is possible that oxidative stress induced by TBT exposure leads to the blockage of arachidonic acid (AA) production in zebrafish embryos, which affects prostacyclin synthesis and consequently the normal development of the heart and blood vessels in zebrafish embryos.

Assessment of the therapeutic potential of probiotics against carbon quantum dots-induced neurotoxicity in common carp (Cyprinus carpio).

Carbon quantum dots (CQDs) have received increasing attention in recent years for their potential toxicity. However, little is known about their neurobehavioral toxicity. This study aimed to investigate the potential mechanisms by which probiotics reduce CQDs neurotoxicity from a brain-gut axis perspective by exposing carp to CQDs and/or probiotics for five weeks. The results showed that CQDs accumulation in the brain reduces the expression of blood-brain-barrier (BBB) related genes in carp, leading to brain damage. In addition, CQDs impaired motor behavior and inhibited acetylcholinesterase activity. These abnormalities were alleviated by probiotic supplementation. Microbiomic analysis showed that probiotics improved the imbalance of intestinal flora caused by CQDs and increased the abundance of Firmicutes. Serum metabolomic analysis showed that probiotic supplementation restored the abnormal metabolic levels associated with neurological, inflammatory, and apoptotic cell death caused by CQDs. Overall, probiotic supplementation improved the CQDs-induced changes in brain damage, gut microbiology, and systemic metabolism. These results suggests that CQDs may cause neurotoxicity via the brain-gut microbial axis.

Iris Recognition Method Based on Parallel Iris Localization Algorithm and Deep Learning Iris Verification.

Biometric recognition technology has been widely used in various fields of society. Iris recognition technology, as a stable and convenient biometric recognition technology, has been widely used in security applications. However, the iris images collected in the actual non-cooperative environment have various noises. Although mainstream iris recognition methods based on deep learning have achieved good recognition accuracy, the intention is to increase the complexity of the model. On the other hand, what the actual optical system collects is the original iris image that is not normalized. The mainstream iris recognition scheme based on deep learning does not consider the iris localization stage. In order to solve the above problems, this paper proposes an effective iris recognition scheme consisting of the iris localization and iris verification stages. For the iris localization stage, we used the parallel Hough circle to extract the inner circle of the iris and the Daugman algorithm to extract the outer circle of the iris, and for the iris verification stage, we developed a new lightweight convolutional neural network. The architecture consists of a deep residual network module and a residual pooling layer which is introduced to effectively improve the accuracy of iris verification. Iris localization experiments were conducted on 400 iris images collected under a non-cooperative environment. Compared with its processing time on a graphics processing unit with a central processing unit architecture, the experimental results revealed that the speed was increased by 26, 32, 36, and 21 times at 4 different iris datasets, respectively, and the effective iris localization accuracy is achieved. Furthermore, we chose four representative iris datasets collected under a non-cooperative environment for the iris verification experiments. The experimental results demonstrated that the network structure could achieve high-precision iris verification with fewer parameters, and the equal error rates are 1.08%, 1.01%, 1.71%, and 1.11% on 4 test databases, respectively.

Theoretical investigation of optical modulators based on graphene-coated side- polished fiber.

The effective mode index (EMI) of a graphene-coated side-polished fiber (GSPF) is calculated numerically. Whereby, the influences of graphene atom layer number, residual radius of SPF, light frequency, scattering rate of graphene, and temperature on the EMI are investigated comprehensively. Two types of mechanisms for the electro-optical absorption modulation are found for such GSPF-based modulator. One mechanism is Pauli blocking effect (PBE) and the other is plasmonic attenuation effect (PAE). With the optimal design parameters, a PBE-based modulator is theoretically predicted to have a 0.0072 dB/µm modulation depth, 2.92 V driving voltage swing, 6.35 nJ/bit power consumption, and 56.2 THz optical modulation bandwidth. It is also predicted that a PAE-based modulator could have a 0.0056 dB/µm modulation depth, 0.6 V driving voltage swing, 0.27 nJ/bit power consumption, and 2.5 THz optical modulation bandwidth. By further optimization, the modulator performance such as the relatively high power consumption and the narrow operation bandwidth can be improved. Owing to their seamless connection to optical fiber networks, the GSPF-based modulators have great potential to be used in fast and high-capacity optical communication systems.

ZnO nanorods/Au hybrid nanocomposites for glucose biosensor.

ZnO nanorods/Au hybrid nanocomposites (ZnO/Au) with Au nanocrystals growing on the surface of ZnO nanorods were synthesized via a simple and facile hydrothermal route. The prepared ZnO/Au nanocomposites were characterized by X-ray diffraction (XRD), scanning electron microscope (SEM) and transmission electron microscopy (TEM) for the morphology study. The composites had a good electron transferring and biocompatibility. The glucose biosensor was fabricated by entrapping glucose oxidase (GOx) in this composite matrix using cross-linking method with glutaraldehyde and Nafion solutions. The proposed biosensor responded to glucose linearly over concentration range of 0.1-33.0 µM (R(2)=0.9956), and the detection limit was 10nM (S/N=3) at an operating potential of +0.55 V in pH 7.4 phosphate buffered solution (PBS). The biosensor exhibited a high and reproducible sensitivity, short response time (within 5s), good storage stability and high affinity to GOx (K(M)(app)=0.41 mM). The effects of electroactive interferents at the testing conditions can be negligible which showed a good selectivity of the biosensor. It is estimated that this ZnO/Au is an attractive material for the fabrication of efficient amperometric biosensors.

Ultrasonic irradiation and its application for improving the corrosion resistance of phosphate coatings on aluminum alloys.

In this paper, ultrasonic irradiation was utilized for improving the corrosion resistance of phosphate coatings on aluminum alloys. The chemical composition and morphology of the coatings were analyzed by X-ray diffraction analysis (XRD) and scanning electron microscopy (SEM). The effect of ultrasonic irradiation on the corrosion resistance of phosphate coatings was investigated by polarization curves and electrochemical impedance spectroscopy (EIS). Various effects of the addition of Nd(2)O(3) in phosphating bath on the performance of the coatings were also investigated. Results show that the composition of phosphate coating were Zn(3)(PO(4))(2).4H(2)O(hopeite) and Zn crystals. The phosphate coatings became denser with fewer microscopic holes by utilizing ultrasonic irradiation treatment. The addition of Nd(2)O(3) reduced the crystallinity of the coatings, with the additional result that the crystallites were increasingly nubby and spherical. The corrosion resistance of the coatings was also significantly improved by ultrasonic irradiation treatment; both the anodic and cathodic processes of corrosion taking place on the aluminum alloy substrate were suppressed consequently. In addition, the electrochemical impedance of the coatings was also increased by utilizing ultrasonic irradiation treatment compared with traditional treatment.

Ultrasound-radiated synthesis of PAMAM-Au nanocomposites and its application on glucose biosensor.

Hybrid nanocomposites of carboxyl-terminated generation 4 (G 4) poly(amidoamine) dendrimers (PAMAM) with gold nanoparticles (AuNPs) encapsulated inside them were synthesized under ultrasound irradiation. The obtained nanocomposites were used to fabricate highly sensitive amperometric glucose biosensor which exhibited a high and reproducible sensitivity of 2.9 mA/mM/cm(2), response time less than 5 s, linear dynamic range from 0.1 to 15.8 microM, correlation coefficient of R(2)=0.9988, and limit of detection (LOD), based on S/N ratio (S/N=3) of 0.05 microM. A value of 2.7 mM for the apparent Michaelis-Menten constant K(M)(app) was obtained. The high sensitivity, wider linear range, good reproducibility and stability make this biosensor a promising candidate for portable amperometric glucose biosensor.

A novel biosensor based on photoelectro-synergistic catalysis for flow-injection analysis system/amperometric detection of organophosphorous pesticides.

In this study, a highly sensitive amperometric biosensor based on photoelectro-synergistic catalysis for detecting organophosphorus pesticides (OPs) in flow-injection analysis (FIA) system has been developed. The acetylcholinesterase enzyme (AChE) was immobilized by adsorption into the nanostructured PbO2/TiO2/Ti, which also acted as the working electrode. This strategy was found to catalyze the oxidative reaction of thiocholine effectively, make the AChE/PbO2/TiO2/Ti biosensor detect the substrate at 0.30 V (vs. SCE), hundreds milli-volts lower than others reported. PbO2/TiO2/Ti and TiO2/Ti electrodes were prepared and investigated with atomic force microscope (AFM). Factors influencing the performance were optimized. The resulting flow system offered a fast, sensitive, and stable response. A value of 1.34 mM for the apparent Michaelis-Menten constant (K(M)(app)) was obtained. A wide linear inhibition response for trichlorfon was observed in the range of 0.01-20 microM with the detection limit of 0.1 nM. The results using this biosensor agreed very well with chromatographic method and we also examined the real samples successfully in this work.

Au-TiO2/Chit modified sensor for electrochemical detection of trace organophosphates insecticides.

In this paper, Au-TiO2/Chit modified electrode was prepared with Au-TiO2 nanocomposite (Au-TiO2) and Chitosan (Chit) as a conjunct. The Au-TiO2 nanocomposite and the films were characterized by electrochemical and spectroscopy methods. A set of experimental conditions was also optimized for the film's fabrication. The electrochemical and electrocatalytic behaviors of Au-TiO2/Chit modified electrode to trace organophosphates (OPs) insecticides such as parathion were discussed in this work. By differential pulse voltammetry (DPV) measurement, the current responses of Au-TiO2/Chit modified electrode were linear with parathion concentration ranging from 1.0 ng/ml to 7.0 x 10(3)ng/ml with the detection limit of 0.5 ng/ml. In order to evaluate the performance of the detection system, we also examined the real samples successfully in this work. It exhibited a sensitive, rapid and easy-to-use method for the fast determination of trace OPs insecticides.