Although thrombin has an important role in both central and peripheral nerve diseases, characterization of the anatomical distribution of its proteolytic activity has been limited by available methods. This study presents the development, challenges, validation and implementation of a novel histochemical method for visualization of thrombin activity in the nervous system. The method is based on the cleavage of the substrate, Boc-Asp(OBzl)-Pro-Arg-4MβNA by thrombin to liberate free 4-methoxy-2-naphthylamine (4MβNA). In the presence of 5-nitrosalicylaldehyde, free 4MβNA is captured, yielding an insoluble yellow fluorescent precipitate which marks the site of thrombin activity. The sensitivity of the method was determined in vitro using known concentrations of thrombin while the specificity was verified using a highly specific thrombin inhibitor. Using this method we determined the spatial distribution of thrombin activity in mouse brain following transient middle cerebral artery occlusion (tMCAo) and in mouse sciatic nerve following crush injury. Fluorescence microscopy revealed well-defined thrombin activity localized to the right ischemic hemisphere in cortical areas and in the striatum compared to negligible thrombin activity contralaterally. The histochemical localization of thrombin activity following tMCAo was in good correlation with the infarct areas per triphenyltetrazolium chloride staining and to thrombin activity measured biochemically in tissue punches (85 ± 35 and 20 ± 3 mU/ml, in the cortical and striatum areas respectively, compared to 7 ± 2 and 13 ± 2 mU/ml, in the corresponding contralateral areas; mean ± SEM; p < 0.05). In addition, 24 h following crush injury, focal areas of highly elevated thrombin activity were detected in teased sciatic fibers. This observation was supported by the biochemical assay and western blot technique. The histochemical method developed in this study can serve as an important tool for studying the role of thrombin in physiological and pathological conditions

Less... See referencing data here

---

Herein, we report the unsymmetric effect on the functional (piezoelectric and semiconducting) properties of cadmium-doped 1D-ZnO nanorods (NRs), which have a higher ionic radius (0.97 Å). The growth of Cd-ZnO NRs, which have a hexagonal wurtzite structure without any secondary CdO phases, along the c-axis was confirmed by the XRD patterns, and oxidation states observed from XPS analyses verified the diffusion of Cd2+ into ZnO NRs. A one-fold reduction in the piezoelectric properties was determined by the fabrication of a nanogenerator, and enhancement in the semiconducting properties was studied using an Ag/Cd-ZnO NRs/Ag device with various wt% of Cd doped into the ZnO NRs lattice. Cd-ZnO NRs improve the photogenerated charge carriers (Iph ∼ 330 μA) compared to pure ZnO NRs (Iph ∼ 213 μA), obtained at a bias voltage of 10 V, a wavelength of 365 nm and a light intensity of 8 mW cm−2. The Cd-ZnO NRs (1 wt%) based sensor shows good photoresponse with a detectivity (D*) limit of 1 × 1011 cm H1/2 W−1 compared to that of pure ZnO NRs (D* = 5.4 × 1010 cm H1/2 W−1). We also demonstrate a self-powered UV sensor (SPUV-S) connected parallel to the ZnO NRs based nanogenerator as an independent power source to drive the Cd-ZnO NRs UV sensor. The low-temperature hydrothermal synthesis of Cd-ZnO NRs is simple, cost-effective, and scalable for industrial applications.

Less... See referencing data here

In this work, a mechanochemical high energy ball milling approach was used to synthesize monoclinic BiVO4 (m-BiVO4) nanoparticles in an attempt to simultaneously reduce the particle size and improve the throughput for practical photocatalytic applications. The effect of annealing to eliminate the induced defects and thus enhance the reactivity was studied on the mechanochemically synthesized BiVO4 nanoparticles. Besides using the conventional characterization tools of XRD, Raman, FE-SEM, HRTEM, XPS and UV-vis diffuse reflectance to examine the crystalline structure, morphology, chemical states and visible light absorption, a customized Kelvin probe coupled with an LED light source was developed as a non-contact tool to study the surface photovoltage (SPV) response for understanding charge generation and separation. The photocatalytic performance was finally evaluated for the degradation of Rhodamine B (RhB) under visible light irradiation to correlate with these physicochemical properties.

Less... See referencing data here