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Nonaqueous organic electrolyte was utilized to etch GaN via photo-electrochemical etching technique. From the point of electrochemical window, the organic electrolyte has wider electrochemical window than conventional aqueous etchants. SEM images show that the pore density is up to 1.2 × 107 per square centimeter. The difference of XPS spectra about survey, Ga 3d and N 1s between the non-etched and freshly etched GaN surface can be explained the formation of Ga(BF4)3. The proposed dissolution mechanism can be broadly applied for explaining the etching process of nonaqueous etchants under the assist of electric field and strong light.

Cyclic GMP-AMP synthase (cGAS) is a double-stranded DNA (dsDNA) sensor that functions in the innate immune system. Upon binding dsDNA in the cytoplasm, cGAS and dsDNA form phase-separated aggregates in which cGAS catalyzes synthesis of 2’3’-cyclic GMP-AMP that subsequently triggers a STING-dependent, type I IFN response. Here, we showed that cytoplasmic RNAs, especially tRNAs, regulate cGAS activity. We discovered that RNAs did not activate cGAS but rather promoted phase separation in vitro. In cells, cGAS colocalized with RNAs and formed phase-separated granules even in the absence of cytoplasmic dsDNA. An Opti-prep gradient analysis of cell lysates showed that the endogenous cGAS was associated with cytoplasmic RNAs in an aggregative form. Further in vitro assays showed that RNAs compete for binding of cGAS with dsDNA and inhibit cGAS activity when the dsDNA concentration is high and promote the formation of phase separations and enhance cGAS activity when the dsDNA concentration is low. Thus, cytoplasmic RNAs regulate cGAS activity by interfering with formation of cGAS-containing aggregates.

Porous gallium nitride (GaN) luminescent materials were fabricated by photoelectrochemical etching using three different 1-ethyl-3-methylimidazolium ([EMIM])-based ionic liquids as the etchants. The as-etched porous GaN presents honeycomb shape, deep gully with some holes in the surroundings, and overlapping hole structure, which are significantly different from the planar GaN. Moreover, photoluminescence (PL) spectra indicates that the porous GaN has more excellent PL performance than the planar GaN. In general, reducing the etching time to 1 min, the PL intensity of porous GaN etched by [EMIM][OTF] is 9.27 times than that of the planar one. These results suggest that porous GaN etched by ionic liquid can be an outstanding substrate in the field of the luminescent material.

Bismuth-modified gallium nitride (Bi/GaN) electrode was fabricated using an in situ plating technique and simultaneously investigated for the detection of Cd2 + by square wave anodic stripping voltammetry (SWASV). Under the optimized conditions, the Bi/GaN electrode showed good linear amperometric responses for Cd2 + in the concentration range from 1 to 150 μg/L. The sensitivity was 0.54418 μA L μg− 1 (i.e., 59.8598 A M− 1) and the limit of detection (LOD) was 0.3 μg/L (i.e., 2.72 nM). Furthermore, the as-prepared Bi/GaN sensor has high repeatability, and retains 95% of its initial stripping peak current after 50 cycles. More importantly, the applicability of the sensor in real samples such as tap water, milk, and fetal bovine serum was researched. The recovery ranges from 92.3 to 106.7%, indicating that the as-fabricated Bi/GaN sensor has potential to monitor Cd2 + in practical environments.

Three-dimensional (3D) metal-semiconductor nanostructures as surface-enhanced Raman scattering (SERS) substrates were designed by in situ electrodeposition of gold nanoparticles (AuNPs) or in situ photodeposition of silver nanoparticles (AgNPs) on gallium nitride (GaN) nanoflowers (NFs) supports fabricated by metal-assisted photochemical etching of single crystalline GaN. 3D AuNPs/GaN NFs and AgNPs/GaN NFs substrates exhibit excellent enhancement effect for Rhodamine 6G (R6G) due to more “hot spots” in the same probing volume compared to 2D GaN based substrates. The enhancement factors of the AuNPs/GaN NFs and AgNPs/GaN NFs substrates are up to 2.1 × 10 7 and 5.9 × 10 7 , respectively, and the corresponding detection limits of R6G are 10 −8 and 10 −10 M, respectively. Moreover, further study reveals both substrates have good reproducibility and long-term stability. The performance of the prepared substrates for biological application was demonstrated by the detection of bovine serum albumin (BSA). A series of characteristic bands of amides suggest BSA can be well adsorbed on the surface of the AuNPs/GaN NFs and AgNPs/GaN NFs substrates, which demonstrates our substrates have good biocompatibility and are promising candidates for SERS biosensors.

In this study, we report for the preparation of nickel phthalocyanine (NiPc) free-standing films on ionic liquid (IL) surface by a physical vapor deposition method. Different from on the solid substrate, the as-obtained film is α phase and with a 2D network structure. In addition, the good transferability of the film make it can be easily transferred onto any substrate for further device applications. The device based on these films shows good photoelectrical property, high stability and high photosensitivity.

Gallium nitride (GaN) nanowires (NWs) were fabricated by metal-assisted photochemical etching (MaPEtch). Gold nanoparticles (AuNPs) as metal catalyst were electrodeposited on the GaN substrate. SEM and HRTEM images show the surface of GaN NWs is smooth and clean without any impurity. SAED and FFT patterns demonstrate GaN NWs have single crystal structure, and the crystallographic orientation of GaN NWs is (0002) face. On the basis of the assumption of localized galvanic cells, combined with the energy levels and electrochemical potentials of reactants in this etching system, the generation, transfer and consumption of electron-hole pairs reveal the whole MaPEtch reaction process. Such easily fabricated GaN NWs have great potential for the assembly of GaN-based single-nanowire nanodevices.

Bismuth nanodendrites (BiNDs) were electrodeposited on planar gallium nitride (GaN) electrode via a differential pulse voltammetric technique to fabricate the non-enzymatic hydrogen peroxide (H2O2) sensor. SEM images revealed that the as-obtained BiNDs had numerous dendrite sub-branches, whose diameters ranged from 136 to 152 nm. The BiNDs/GaN electrode showed linear amperometric responses for H2O2 in the concentration range from 10 µM to 1 mM with the sensitivity of 60.0 μA mM−1 cm−2. Another linear range was from 1 to 10 mM with the sensitivity of 23.3 μA mM−1 cm−2. The limit of detection (LOD) was 5 µM with the signal-to-noise ratio of 3. The applicability of the sensor was investigated to the H2O2 detection in real samples such as fetal bovine serum and milk, and the sensor exhibited excellent anti-interference capacity. The achieved results indicate that the as-prepared BiNDs/GaN sensor with good reproducibility and long-term stability was promising for detecting H2O2 in practical environments.

Gallium nitride (GaN) surface was etched by 0.3 M ethylenediamine tetraacetic acid disodium (EDTA-2Na) via photoelectrochemical etching technique. SEM images reveal the etched GaN surface becomes rough and irregular. The pore density is up to 1.9 × 10 9 per square centimeter after simple acid post-treatment. The difference of XPS spectra of Ga 3d, N 1s and O 1s between the non-etched and freshly etched GaN surfaces can be attributed to the formation of Ga–EDTA complex at the etching interface between GaN and EDTA-2Na. The proposed complexation dissolution mechanism can be broadly applicable to almost all neutral etchants under the prerequisite of strong light and electric field. From the point of view of environment, safety and energy, EDTA-2Na has obvious advantages over conventionally corrosive etchants. Moreover, as the further and deeper study of such nearly neutral etchants, GaN etching technology has better application prospect in photoelectric micro-device fabrication.

Porous gallium nitride (PGaN) layers were fabricated by metal-assisted photochemical etching (MaPCE) using electrodeposited platinum nanoparticles (PtNPs) or gold nanoparticles (AuNPs) as catalysts. After identification of a suitable negative potential and appropriate cyclic voltammetry (CV) conditions, high-density PtNPs or AuNPs were deposited onto a planar GaN substrate. Based on the concrete numerical values of energy levels, the generation, transfer and consumption of electrons and holes, and the assumption that localized galvanic cells are formed, an etching mechanism was proposed which may provide theoretical guidance for future work on etching of GaN and other semiconductor materials. Keywords: Gallium nitride, Metal-assisted photochemical etching, Electrodeposition, Noble metal nanoparticles

Here we report the electrodeposition of gold nanoparticles (AuNPs) onto porous GaN electrode obtained by photoelectrochemical etching planar GaN to fabricate a non-enzymatic hydrogen peroxide (H2O2) sensor. SEM images revealed porous GaN has uniformly high-porosity structure and the diameter of AuNPs is 5–16 nm. The AuNPs/porous GaN electrode exhibited good electrocatalytic activity toward the reduction of H2O2 and performed as amperometric sensor for the detection of H2O2. The AuNPs/porous GaN electrode showed linear amperometric responses for H2O2 in the concentration range from 10 to 100 μM with the sensitivity of 281.5 μA mM−1. The limit of detection (LOD) is 2 μM with a signal-to-noise ratio of 3. In addition, the AuNPs/porous GaN electrode exhibited good repeatability, reproducibility, selectivity and long-term stability for H2O2 detection, in the meanwhile, AuNPs showed excellent adhesive capacity to the porous GaN electrode, which was tested by continually sonicating the AuNPs/porous GaN electrode for 3 h. Above results demonstrated this simply prepared H2O2 sensor has good practicability and is promising to measure the analyte in practical applications.

Here we report an environment-friendly approach to fabricate porous GaN photoelectrode using ionic liquid as the etchant. SEM images revealed photo-assisted electrochemical etching (PECE) has better etching effect than electrochemical etching (ECE). Furthermore, Raman spectra demonstrated porous GaN obtained by PECE has better lattice integrity than that obtained by ECE. The photocurrent of porous GaN prepared by PECE is six times and two times of planar and porous GaN fabricated by ECE, respectively. Above results indicated porous GaN obtained by PECE can be a promising photoelectrode for optoelectronic applications.

We demonstrated a simple method for the fabrication of gold nanoparticles/porous GaN composite by using photo-assisted electrochemical etching and electrochemical deposition methods based on planar GaN film for photocatalytic degradation of methyl orange. Scanning electron microscopy (SEM) images revealed porous GaN has uniformly high-porosity structure and the diameter of gold nanoparticles (AuNPs) is 4–20 nm. Moreover, the pore diameter of porous GaN can be easily adjusted by changing etching time. Uniformly small AuNPs can be obtained by optimized deposition cycles of cyclic voltammetry (CV). The photocatalysis activity under simulated sunlight irradiation was enhanced via electrodepositing AuNPs onto porous GaN substrate. Above results indicated such porous GaN could be an excellent candidate to study the photocatalytic performance of porous wide band-gap semiconductor-based composite materials.

Free-standing films of metal octaethylporphyrins (MOEPs) were prepared for the first time by a physical vapor deposition on surface of an ionic liquid (IL). Different from those on solid surfaces, the as-obtained films were very compact and with plannar structure. The monitoring of time-dependent process indicated that the high surface energy of IL and the strong π…π interaction between MOEP molecules played key roles in forming such films. Furthermore, the as-obtained film showed good transferability, which made it possible to be easily transferred to any substrates for further device application. More importantly, the prototype photodetectors based on free-standing films of MOEP showed ultra flexibility, mechanical stability, and durability.

This study determined the level of phytonutrients in mungbean and soybean sprouts compared to mature mungbean grain and vegetable soybean. The comparison included landraces and improved mungbean and soybean varieties to assess the effect of breeding on the phytonutrient content of both crops. Sprouting mungbean enhanced vitamin C content 2.7-fold compared to mature mungbean grain. Relatively old mungbean accessions were superior in protein, calcium (Ca), iron (Fe), zinc (Zn), carotenoid and vitamin C content compared to improved mungbean lines at the fully mature stage. With regard to nutritional value, the vegetable soybean stage was superior to soybean sprouts in terms of content of protein (14% increase), Zn (45%), Ca (72%), and Fe (151%). Isoflavones, reported to have beneficial effects on human health, are found at high concentrations in soybean sprouts and could easily provide the recommended anticarcinogenic dose range from 1.5 to 2.0mg/kg of body weight per day.

Tungsten oxide thin films were electrochemically deposited onto gallium nitride for the first time and directly used for the fabrication of acetone sensor. This sensor could operate at room temperature and had high sensitivity, fast response, and long-term stability. Moreover, the detection limit of the sensor could reach 0.1 ppm, implying its potential application in non-invasive detection of diabetes.

Background and Aims Hepatocellular carcinoma (HCC) is one of the most common malignancies worldwide. Aberrant activation of sonic hedgehog (Shh) signaling pathway plays important roles in tumorigenesis and progression of several tumors. Cyclopamine, an important inhibitor of Shh signaling pathway, can induce cell apoptosis. However, the mechanisms underlying cyclopamine-induced apoptosis are not well understood. The aim of this study is to determine the expression of the Shh signaling pathway components in HCC and to investigate the mechanisms underlying cyclopamine-induced apoptosis in HCC cells. Methods Shh signaling components (Shh, Ptch, Smo and Gli-1) expression levels were evaluated by immunohistochemistry on tissue microarrays containing 98 HCCs with paired adjacent noncancerous liver tissues. The relationships between sonic hedgehog signal pathway and clinicopathological factors were analyzed in HCC. Cell viability was analyzed by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) assay. Apoptosis was detected by flow cytometry. mRNA and protein levels were analyzed by RT-PCR and Western blot, respectively. Results Shh, Ptch, Smo and Gli-1 were overexpressed in HCC tissues compared with paired adjacent noncancerous liver tissue. Activated Shh signaling pathway was associated with tumor size, capsular invasion and vascular invasion in HCC. Cyclopamine remarkably decreased cell viability, induced apoptosis and downregulated Bcl-2 expression in HCC cells. Conclusions Shh signaling pathway plays an important role in HCC tumorigenesis and progression, indicating that Shh signaling pathway is a potential therapeutic target for HCC. Cyclopamine induces apoptosis through downregulating Bcl-2 in HCC.

alpha-MoO3 whiskers were prepared via an oxidation process of a Mo slice in oxygen. MoO3 vapors condensed to form the alpha-MoO3 whiskers with white color. On surfaces of the MoO3 whiskers, the atom ratio of oxygen to molybdenum was 4.4, which was higher than that of bulk MoO3. (C) 2004 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

The growth behavior and surface morphology of a rough film system, deposited on silicone oil drop surfaces by a r.f. magnetron sputtering method, have been studied. An anomalous film growth relaxation is observed during the deposition process. The relaxation rate is extremely sensitive to the substrate temperature. The surface morphology at the micrometer length scale is very susceptible to the substrate temperature, the incident r.f. capacity, and the nature of the solid substrate on which the oil drop is dripped. A discussion on the physical origins of these phenomena is also presented.

AIM: To investigate the effects of Gli-1 small interference RNA (siRNA) on Huh7 cells, and the change of Bcl-2 expression in Huh7 cells. METHODS: Human hepatocellular carcinoma cells Huh7 were used. Cell viability was analyzed by 3-(4, 5-Dimethylthiazol-2-yl)-2, 5-diphenyl tetrazolium bromide (MTT) assay. The expressions of Gli-1 and Bcl-2 family members were detected by RT-PCR and Western blot. Apoptosis was detected by Flow cytometry using propidium iodide, measured by Hoechst 33258 staining using Advanced Fluorescence Microscopy and caspase-3 enzymatic assay. Cell growth was analyzed after treatment with Gli-1 siRNA and 5-fluorouracil (5-Fu). RESULTS: Inhibition of Gli-1 mRNA in Huh7 cells through Gli-1 siRNA reduced cell viability. Gli-1 siRNA treatment also induced apoptosis by three criteria, increase in the sub-G1 cell cycle fraction, nuclear condensation, a morphologic change typical of apoptosis, and activation of caspase-3. Gli-1 siRNA was also able to down-regulate Bcl-2. However, Gli-1 siRNA resulted in no significant changes in Bcl-xl, Bax, Bad, and Bid. Furthermore, Gli-1 siRNA increased the cytotoxic effect of 5-Fu on Huh7 cell. CONCLUSION: Down-regulation of Bcl-2 plays an important role in apoptosis induced by Gli-1 siRNA in HCC cells. Combination Gli-1 siRNA with chemotherapeutic drug could represent a more promising strategy against HCC. The effects of the strategies need further investigation in vivo and may have potential clinical application.

To investigate the effects of 2-methoxyestradiol (2-ME) on 2 myeloid leukemia cell lines HL-60 and U937, and to explore its mechanisms.Human myeloid leukemia cells HL-60 and U937 were used. Measurement of mitochondrial membrane potential (Dym) was performed using 5,5',6,6'-Tetrachloro-1,1',3,3'- tetraethylbenzimidazolylcarbocyanine iodide ( JC-1). Apoptosis and cellular nitric oxide (NO) were detected by flow cytometry using Annexin V and NO sensor dye. Superoxide anion was measured with a fluorescent plate reader by dihydroethidium (DHE). Cytotoxicity was analyzed by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium assay.2-ME resulted in viability decrease in a dose-dependent manner. 2-ME treatment also generated reactive oxygen species (ROS), including NO and superoxide anions, which resulted in mitochondria damage. 2-ME-induced apoptosis was correlated with an increase in ROS. The quenching of ROS with N-acetyl-L-cysteine protected leukemia cells from 2-ME cytotoxicity and prevented apoptosis induction by 2-ME. Furthermore, the addition of manumycin, a farnesyltransferase inhibitor, significantly enhanced apoptosis induced by 2-ME.Cellular ROS generation plays an important role in the cytotoxic effect of 2-ME. It is possible to use ROS generation agents, such as manumycin, to enhance the antileukemic effect. The combination strategy needs further in vivo justification and may have potential clinical application.