Search

Background The protein expressions of brain-derived neurotrophic factor (BDNF) can be elevated by transcranial ultrasound stimulation in the rat brain. Objective The purpose of this study was to investigate the effects and underlying mechanisms of BDNF enhancement by low-intensity pulsed ultrasound (LIPUS) on traumatic brain injury (TBI). Methods Mice subjected to controlled cortical impact injury were treated with LIPUS in the injured region daily for a period of 4 days. Western blot analysis and immunohistochemistry were performed to assess the effects of LIPUS. Results The results showed that the LIPUS treatment significantly promoted the neurotrophic factors BDNF and vascular endothelial growth factor (VEGF) at day 4 after TBI. Meanwhile, LIPUS also enhanced the phosphorylation of Tropomyosin-related kinase B (TrkB), Akt, and cAMP-response element binding protein (CREB). Furthermore, treatment with LIPUS significantly decreased the level of cleaved caspase-3. The reduction of apoptotic process was inhibited by the anti-BDNF antibody. Conclusions In short, post-injury LIPUS treatment increased BDNF protein levels and inhibited the progression of apoptosis following TBI. The neuroprotective effects of LIPUS may be associated with enhancements of the protein levels of neurotrophic factors, at least partially via the TrkB/Akt-CREB signaling pathway. [ABSTRACT FROM AUTHOR]

Trace levels of antibiotics in water bodies could present a public health risk. However, advanced oxidation can potentially transform trace antibiotics; therefore, this study investigates the degradation of typical pharmaceuticals such as ofloxacin (OFL) in aqueous solution by the UV/H2O2 advanced oxidation process. The results show that OFL could be rapidly degraded by UV/H2O2, and that the degradation process is dependent on the H2O2 concentration and on the initial concentrations of OFL. The pseudo-first-order rate constant (k) of OFL is significantly improved by ·OH generated by H2O2; however, with an increased OFL concentration, the k declines. In actual water bodies, the rate constant of OFL is lower than that in ultrapure water. Further analysis has indicated that the acidic and basic environments or the existence of natural organic matter and chloride ion inhibit the degradation of OFL. The experimental results indicate that the laboratory results could not be extended directly to actual water treatment without further consideration. Six degradation products of OFL were determined by ultra-performance liquid chromatography-high resolution mass spectrometry. The degradation pathways mainly encompass ring openings at both the piperazinyl substituent and the quinolone moiety. [ABSTRACT FROM AUTHOR]

High speed stamping process is used to high strength and high electrical conductivity phosphor bronze with extremely high strain rates more than 10³ s-1. This study on the dynamic tensile behaviour and deformational mechanism is to optimise the high speed stamping processes and improve geometrical precision in finished products. Thus, the tensile properties and deformation behaviour of C5191 phosphor bronze under quasi-static tensile condition at a strain rate of 0.001 s-1 by electronic universal testing machine, and dynamic tensile condition at strain rate of 500, 1000 and 1500 s-1 by split Hopkinson tensile bar (SHTB) apparatus were studied. The effects of strain rate and the deformation mechanism were investigated by means of SEM and TEM. The results showed that the yield strength and tensile strength of C5191 phosphor bronze under high strain rates deformation increased by 32.77% and 11.07% respectively compared with quasi-static condition, the strain hardening index increases from 0.075 to 0.251, and the strength of the material strain rates sensitivity index change from 0.005 to 0.022, which presented a clear sensitive to strain rates. Therefore, it is claimed that the dominant deformation mechanism was changed by the dislocation motion under different strain rates, and the ability of plastic deformation of C5191 phosphor bronze increased due to the number of movable dislocations increased significantly, started multi-line slip, and the soft effect of adiabatic temperature rise at the strain rate ranging from 500 to 1500 s-1. [ABSTRACT FROM AUTHOR]

Graphene hybrids comprised of diverse functional materials have shown exceptional performance. However, only 2D composites were widely studied, the understanding of graphene hybridization behavior with complex 3D nanostructures remains unclear. In this work, we investigate how the graphene hybridization is affected by the presence of 3D nanovoids, and the corresponding influence on the electrocatalysis of hydrogen peroxide reduction. The 3D nanovoids of the cobalt manganese oxide (CMO) increase the amount of graphene captured in the composites for the higher surface areas, uniform porosity, and improved electrocatalytic activities. The formation of graphene/CMO interfaces contributes to the efficient H 2 O 2 reduction at the more positive onset potentials than graphene or CMO material alone. Controls of the inhomogeneous distribution and void-filling behavior of graphene on CMO surface are critical to achieve optimal, synergistic electrocatalysis. The graphene/CMO hybrids with full graphene coverage exhibit the greatly enhanced H 2 O 2 sensitivity by 2900 and 48 times greater than commercial products and bare CMO, respectively. [ABSTRACT FROM AUTHOR]

In this study, the K6509 cobalt-base superalloy were heat treated at different temperatures and the microstructure was detected by scanning electrical microscopy and electrical probe micro-analyzer. In as-cast K6509, the MC carbides are present as a discrete, blocky dispersion with a well-distributed Chinese script morphology and the eutectics (γ+M23C6) and (γ+M7C3) can be seen. With the temperature increasing, the MC arise degeneration. Below 1150 o C, the script-like MC is dominant; reaching 1200 o C, the particle and block of MC are dominant; reaching 1250 o C, few script-like MC is present. In as-cast alloy, the M23C6 and M7C3 carbides are lamellar eutectic with matrix. When temperature is up to 1150 o C, the eutectic (γ+M23C6) disappears; however, much eutectic (γ+M7C3) can be found. When the temperature reaches 1200 o C, a large amount of eutectic M7C3 is dissolved, and some pores form in the matrix, and some zones rich in Cr form around the pores. When the temperature is above 1250 o C, many pores form in the matrix, the cause of pores is need to be studied further. [ABSTRACT FROM AUTHOR]

This paper describes a high-performance thin-film transistor (TFT) fabricated using TiO2 and InGaZnO semiconducting layers. Favorable transistor characteristics, including a low threshold voltage of 0.45 V, a small subthreshold swing of 174 mV/decade, and a high field effect mobility of 19 cm²/V s at a low drive voltage of <2 V, were achieved. This favorable performance mainly resulted from the combined effect of the high-dielectric-constant gate dielectric and the TiO2-InGaZnO active semiconductor bilayer, which reduced the operating voltage, enhanced the device mobility, and improved the transistor gate swing. This TiO2-InGaZnO TFT exhibits great potential for future high-speed and high-resolution display applications. [ABSTRACT FROM AUTHOR]

Caveolin-1 (Cav-1) interacts with and mediates protein trafficking and various cellular functions. Derlin-1 is a candidate for the retrotranslocation channel of endoplasmic reticulum proteins. However, little is known about how Derlin-1 mediates glycosylated protein degradation. Here, we identified Cav-1 as a key player in Derlin-1- and p97-mediated cyclooxygenase 2 (COX-2) ubiquitination and degradation. Derlin-1 augmented the interaction of Cav-1 and COX-2 and mediated the degradation of COX-2 in a COX-2 C terminus-dependent manner. Suppression of Cav-1 decreased the ubiquitination of COX-2, and mutation of Asn-594 to Ala to disrupt N-glycosylation at the C terminus of COX-2 reduced the interaction of COX-2 with Cav-1 but not Derlin-1. Moreover, suppression of p97 increased the ubiquitination of COX-2 and up-regulated COX-2 but not COX-1. Cav-1 enhanced the interaction of p97 with Ufd1 and Derlin-1 and collaborated with p97 to interact with COX-2. Cav-1 may be a cofactor in the interaction of Derlin-1 and N-glycosylated COX-2 and may facilitate Derlin-1- and p97 complex-mediated COX-2 ubiquitination, retrotranslocation, and degradation. [ABSTRACT FROM AUTHOR]

Excitotoxicity mediated by overactivation of A-methyl-D-aspartate receptors (NMDARs) has been implicated in a variety of neuropathological conditions in the central nervous system (CNS). It has been suggested that N-methyl-D-aspartate (NMDA) neurotoxicity is developmentally regulated, but the definite pattern of the regulation has been controversial, and the underlying mechanism remains largely unknown. Here, we show that NMDA treatment leads to significant cell death in mature (9 and 12 days in vitro) hippocampal neurons or hippocampi of young postnatal day 12 and adult rats but not in immature (3 and 6 days in vitro) neurons or embryonic day 18 and neonatal rat hippocampi. In contrast, NMDA promotes survival of immature neurons against tropic deprivation. Interestingly, it is found that NMDA preferentially activates p38 MAPK in mature neuron and adult rat hippocampus, but it favors ERK½ activation in immature neuron and postnatal day 0 rat hippocampus. Moreover, it is shown that NMDA neurotoxicity in mature neuron is mediated via p38 MAPK activation, and neuroprotection in immature neuron is mediated via ERK½ activation, whereas all these effects are NR2B-containing NMDAR-dependent, as well as Ca2+-dependent. We also revealed that mature and immature neurons showed no difference in the amplitude of NMDA-induced intracellular calcium ([Ca2+]i) increase. However, the basal level of [Ca2+]i is shown to elevate with the maturation of neuron, and this elevation is attributable to the changes in NMDA neurotoxicity but not to the switch of the NMDAR signaling pathway. Taken together, our results suggest that a switch of NMDA receptor-favorite intracellular signal pathways from ERK½ to p38 MAPK and the elevated basal level of [Ca2+]i with age might be critical for the developmental changes in NMDA neurotoxicity in the hippocampal neuron. [ABSTRACT FROM AUTHOR]

Abstract: In this paper, ultra-high vacuum chemical vapor deposition (UHV/CVD) was employed to synthesize silicon–germanium (SiGe), and sequence to endure annealing treatment. Morphological characterization, roughness, and microstructural morphology were observed by means of scanning electron microscopy (SEM), atomic force microscopy (AFM), and transmission electron microscopy (TEM). The elements distribution, crystallographic, and nanomechanical behavior were carried out using energy-dispersive X-ray spectroscopy (EDS) mapping technique, X-ray diffraction (XRD), and nanoindentation technique. The annealing treated SiGe leads to the 2D germanium segregation on the surface. The phenomenon is interpreted in terms of dislocation-induced structural changes in annealing treatment. Thus, the dislocation propagation in the microstructure was observed. Subsequently hardness and elastic modulus were increased because of a comparatively unstable microstructure after annealing treatment. [Copyright &y& Elsevier]

A new adsorbent, ordered mesoporous Fe-modified ZrO2, was prepared and applied for the adsorption of arsenite [As(III)] and arsenate [As(V)] from water. The adsorbent showed higher efficiency for the removal of As(III) and As(V) than that of unmodified mesoporous ZrO2, especially of As(III) without pre-oxidation. The maximum uptake at pH 7.0 was 80 mg g-1 for As(III) and 45 mg g-1 for As(V). The behavior of arsenic adsorption onto Fe-modified ZrO2 was investigated by adsorption isotherms, adsorption kinetics, and the effect of pH on adsorption. The adsorption equilibrium of arsenite was rapid, with 90% adsorption within 1 h. Furthermore, the interactions of As(V) and As(III) with adsorbent were investigated using electrophoretic mobility (EM) measurements and Fourier transform infrared (FTIR) spectroscopy. The adsorption of As(V) and As(III) decreased the isoelectric point of Fe-modified ZrO2 from 6.00 to 3.00 and 4.51, respectively, suggesting the formation of negatively charged inner-sphere complexes for both arsenic species. The results of FTIR suggested that the -OH band on the surface was the adsorption sites. The more adsorption sites were formed on mesoporous ZrO2 modified with Fe, which possessed abundant surface hydroxyl groups, resulting higher efficiency for arsenic removal. [ABSTRACT FROM AUTHOR]

CuOx-doped α-FeOOH (CuOx–FeOOH) nanorods were synthesized by controlling the reaction between ferrous sulfate, cupric sulfate and sodium borohydride at ambient atmosphere. The resulting materials were characterized by transmission electron microscopy, X-ray powder diffraction, Fourier transform infrared spectroscopy, and X-ray photoelectron spectroscopy. CuOx–FeOOH was mainly composed of α-FeOOH and CuOx (CuO and Cu2O). The catalyst was found to be highly effective for the degradation of endocrine disruptors, including dimethyl phthalate, 2,4-dichlorophenoxyacetic acid, and 2,4-dichlorophenol in the presence of H2O2 and UVA at neutral pH. By the total organic carbon and GC–MS analysis, the degradation process of DMP was shown to proceed with the cleavage of C–O bond in ester linkages and the phenyl ring opening into organic acids and CO2. The studies of ꔷOH formation and cyclic voltammetry revealed that the H2O2 was decomposed into ꔷOH or O2 by the promotion of metal oxide. The obtained results showed that the synergistic effect between CuOx and α-FeOOH markedly enhanced the H2O2 decomposition into ꔷOH in CuOx–FeOOH suspension, causing the higher catalytic reactivity. A possible reaction mechanism was proposed. [Copyright &y& Elsevier]

SiO2–C2H4–ferrocene (SiCFe) was synthesized by covalent grafting of ferrocene on functionalized silica gel with a –C2H4– linkage. On the basis of characterization by diffuse reflectance UV–vis spectra (DRS) and Fourier transform infrared spectra (FT-IR), ferrocene has been successfully anchored on the silica gel. Under UVA (λmax = 365 nm) irradiation, the catalyst exhibited high photocatalytic activity in the degradation of Acid Red B (ARB), especially in the presence of H2O2. Meanwhile, the catalytic activity of SiCFe was maintained effectively even after reused for 4 times without any significant destruction of ferrocene. The influence of initial solution pH and wavelength of UV light on the catalyst''s activity was also investigated. Electron spin resonance (ESR) studies revealed that both ·OH and HO2·/O2·− radicals were involved as the active species in the ARB degradation process. Furthermore, results of total organic carbon (TOC) and FT-IR analysis indicated that ARB degradation proceeded by the cleavage of —N=N—,followed by hydroxylation and opening of phenyl rings to form aliphatic acids and further oxidization of the aliphatic acids to produce carbon dioxide and water. A possible reaction mechanism was proposed on the basis of all the information obtained under various experimental conditions. [Copyright &y& Elsevier]