GaN Powders Research Articles

Jian Gan powder ameliorates immunological liver injury in mice by modulating the gut microbiota and metabolic profiles

BackgroundImmunological liver injury (ILI) is a common liver disease associated with the microbiota-gut-liver axis. Jian Gan powder (JGP) exhibits both protective and therapeutic effects on hepatitis virus-induced ILI in the clinic. However, the underlying mechanisms remain elusive. The aim of this study is to investigate the hepatoprotective effects and associated mechanisms of JGP in the context of gut microbiota, utilizing a mouse model of ILI.MethodsThe mouse model was established employing Bacillus Calmette-Guérin (BCG) plus lipopolysaccharide (LPS). Following treatment with JGP (7.5, 15, or 30 g/kg), serum, liver, and fresh fecal samples were analyzed. 16S rRNA gene sequencing and untargeted metabolomics profiling were performed to assess the role of JGP on the gut microbiota and its metabolites.ResultsJGP treatment markedly reduced serum IFN-γ, IL-6, IL-22, and hepatic p-STAT3 (phosphorylated transducer and activator of transcription-3) expression. In contrast, JGP increased the percentage of proliferating cell nuclear antigen-positive liver cells in treated mice. Fecal 16S rRNA gene sequencing revealed that JGP treatment restored the levels of Alloprevotella, Burkholderia-Caballeronia-Paraburkholderia, Muribaculum, Streptococcus, and Stenotrophomonas. Additionally, metabolomics analysis of fecal samples showed that JGP restored the levels of allylestrenol, eplerenone, phosphatidylethanolamine (PE) (P-20:0/0:0), sphingomyelin (SM) d27:1, soyasapogenol C, chrysin, and soyasaponin I.ConclusionsJGP intervention improves ILI by restoring gut microbiota and modifying its metabolic profiles. These results provide a novel insight into the mechanism of JGP in treating ILI and the scientific basis to support its clinical application.

The effect of Jian Gan powder on the proliferation, migration and polarization of macrophages and relative mechanism

Context Jian Gan powder (JGP) is a Chinese medicine compound comprised ginseng, Radix Paeoniae Alba, Radix Astragali, Salvia miltiorrhiza, Yujin, Rhizoma Cyperi, Fructus aurantii, Sophora flavescens, Yinchen, Bupleurum and licorice. Objective This study explored the inhibitory effects, polarization and potential mechanisms associated with JGP in macrophages. Materials and methods RAW264.7 cells were randomly divided into six groups for 24 h: control, lipopolysaccharide (LPS), overexpression, 1% JGP, 2% JGP, 4% JGP, 8% JGP and 16% JGP. The effects of JGP on RAW264.7 cell proliferation were assessed using colony formation assays and cell counting kit-8 (CCK-8) assays. The Transwell assay was used to evaluate its impact on RAW264.7 cell migration. Moreover, we analysed the interleukin-6 (IL-6)/signal transducer and activator of the transcription 3 (IL-6/STAT3) signaling pathway using quantitative real-time PCR and Western blotting. Furthermore, we examined the M1/M2 polarization levels. Results Unlike LPS stimulation, JGP serum treatment markedly suppressed macrophage proliferation and migration capacity, while STAT3 overexpression enhanced RAW264.7 cell proliferation and migration. JGP inhibited the proliferation and migration of RAW264.7 cells by attenuating the IL-6/STAT3 signaling pathway. Furthermore, it inhibited macrophage M1 polarization, promoting M2 polarization. Discussion and conclusions JGP effectively suppressed the cellular function of RAW264.7 cells by down-regulating the IL-6/STAT3 signaling pathway and modulating macrophage M1/M2 polarization. These findings provide valuable theoretical and experimental basis for considering the potential clinical application of JGP in the treatment of immune-mediated liver injury in clinical practice.

Hexagonal Nanocrystal Growth of Mg or Zn from Incorporation in GaN Powders Obtained through Pyrolysis of a Viscous Complex Compound and Its Nitridation

Hexagonal nanocrystals were obtained from Zn-doped GaN powders and Mg-doped GaN powders, which were synthesized via pyrolysis of a viscous complex compound, followed by its nitridation. XRD showed well-defined peaks for hexagonal GaN with an average crystal size of 21.3 nm. Scanning electron microscopy showed an amorphous and porous appearance in surface morphology, which could be related to the combustion process. Energy-dispersive spectroscopy characterization showed contributions of gallium, nitrogen, and small traces of Zn and Mg in the GaN samples. TEM showed the presence of well-defined hexagonal nanocrystals with an area of 75.9 nm2 for the Zn-doped GaN powders and an area of 67.7 nm2 for the Mg-doped GaN powders. The photoluminescence spectra showed an emission energy of 2.8 eV (431.5 nm) for the Zn-doped GaN powders, while the Mg-doped GaN powders showed energies in the range from 2.7 eV to 2.8 eV (460.3 nm–443.9 nm). The Raman scattering showed spectra where the vibration modes A1(TO), E1(TO), and E2(High) could be observed, which are characteristic of hexagonal GaN.

Obtaining of Mg-Zn Co-Doped GaN Powders via Nitridation of the Ga-Mg-Zn Metallic Solution and Their Structural and Optical Properties.

Mg-Zn co-dopedGaN powders via the nitridation of a Ga-Mg-Zn metallic solution at 1000 °C for 2 h in ammonia flow were obtained. XRD patterns for the Mg-Zn co-dopedGaN powders showed a crystal size average of 46.88 nm. Scanning electron microscopy micrographs had an irregular shape, with a ribbon-like structure and a length of 8.63 µm. Energy-dispersive spectroscopy showed the incorporation of Zn (Lα 1.012 eV) and Mg (Kα 1.253 eV), while XPS measurements showed the elemental contributions of magnesium and zinc as co-dopant elements quantified in 49.31 eV and 1019.49 eV, respectively. The photoluminescence spectrum showed a fundamental emission located at 3.40 eV(364.70 nm), which was related to band-to-band transition, besides a second emission found in a range from 2.80 eV to 2.90 eV (442.85-427.58 nm), which was related to a characteristic of Mg-doped GaN and Zn-doped GaN powders. Furthermore, Raman scattering demonstrated a shoulder at 648.05 cm-1, which could indicate the incorporation of the Mg and Zn co-dopants atoms into the GaN structure. It is expected that one of the main applications of Mg-Zn co-doped GaN powders is in obtaining thin films for SARS-CoV-2 biosensors.

Effect of growth temperature on nitrogen incorporation into GaAsN during liquid-phase epitaxy

We studied the growth temperature effect on nitrogen incorporation into GaAsN layers grown by liquid-phase epitaxy (LPE). The growth of dilute nitrides at nearly equilibrium conditions during LPE presents several major challenges: low solubility of nitrogen in Ga-melt, small incorporation efficiency in the solid and high volatility of nitrogen. GaAsN layers are grown from three different initial epitaxy temperatures: 580 °C, 680 °C and 780° C using GaN powder in the melt as a source of nitrogen. The N content in GaAsN is estimated from X-ray diffraction curves applying Vegard’s law. The local microstructure and surface morphology of the grown layers are studied by Fourier-transform infrared spectroscopy and atomic force microscopy measurements, respectively. The absorption edge and the composition dependence of the effective band gap are determined by employing optical transmission and surface photovoltage spectroscopies.

Effects in the Optical and Structural Properties Caused by Mg or Zn Doping of GaN Films Grown via Radio-Frequency Magnetron Sputtering Using Laboratory-Prepared Targets

GaN films doped with Mg or Zn were obtained via radio-frequency magnetron sputtering on silicon substrates at room temperature and used laboratory-prepared targets with Mg-doped or Zn-doped GaN powders. X-ray diffraction patterns showed broadening peaks, which could have been related to the appearance of nano-crystallites with an average of 7 nm. Scanning electron microscopy and transmission electron microscopy showed good adherence to silicon non-native substrate, as well as homogeneity, with a grain size average of 0.14 µm, and 0.16 µm for the GaN films doped with Zn or Mg, respectively. X-ray photo-electron spectroscopy demonstrated the presence of a very small amount of magnesium (2.10 mol%), and zinc (1.15 mol%) with binding energies of 1303.18, and 1024.76 eV, respectively. Photoluminescence spectrum for the Zn-doped GaN films had an emission range from 2.89 to 3.0 eV (429.23–413.50 nm), while Mg-doped GaN films had an energy emission in a blue-violet band with a range from 2.80 to 3.16 eV (443.03–392.56 nm). Raman spectra showed the classical vibration modes A1(TO), E1(TO), and E2(High) for the hexagonal structure of GaN.

Facile method for the synthesis of zinc- or magnesium-doped gallium nitride powders from gallium metal

We describe a facile method for synthesizing high-purity Zn-doped and Mg-doped GaN powders from Ga metal in supercritical ammonia at a moderate reaction temperature using ZnX2 and MgX2 (X = F, Cl, Br, or I) as combined mineralizers and doping agents. Successful doping of Zn or Mg into the GaN matrix was indicated by characteristic bands in the photoluminescence spectra of the crystals at 10 K. The results suggest that the halide ion plays an important role in the transformation of Ga metal to GaN powder.

IR Laser Induced Emission Spectra of GaN Nanoceramic

Currently, the researchers from around the world pay a lot of attention to search new white light generation sources. Such a device would have huge application potential in the lighting industry. The advantage of a broadband white light source is no necessity to mix few emission lines to obtain a white luminescence, as it is in case of the LED devices. Here, we investigate the broadband laser induced emission spectra of GaN nanoceramic measured under three different infrared excitation lines (1064, 975 and 808 nm). The GaN powder was obtained by thermal decomposition method while the nanoceramic was prepared using low temperature high pressure (LTHP) technique. The sample crystallizes in the hexagonal wurtzite structure and theoretical value of their average grain size calculated using Scherrer equation was 12 nm. The optical characterization of LIE spectra of GaN nanoceramic included the measurements of emission intensity as a function of power density, ambient pressure and luminescence kinetics. The emission spectra were recorded in both VIS (400-900 nm) and NIR (1200-2500 nm) regions (Fig. 1a,1b). It was found that the power dependence exhibit threshold behavior typical for avalanche process for all three excitation lines. The luminescence kinetics measurements show that rise and decay times of LIWE are extremely short in comparison to dielectric materials. It turned out that calculated x and y parameters of recorded emissions lie in the warm region of the CIE chromaticity diagram confirming their low color temperature regardless of the excitation wavelength (Fig. 1c). Finally, a general mechanism of LIE spectra in GaN nanoceramic is discussed.Figure 1. The LIWE intensity of GaN nanoceramic under 975 nm as a function of increasing pumping power density in VIS and NIR regions (a,b). The CIE chromaticity diagram of LIWE generated from GaN nanoceramic upon three various excitation wavelengths (c). The image of LIWE during experiment (d). Figure 1

The Manufacture of GaN Powder in Plasma

In this paper, the preparation technology of GaN powder has been studied by using of plasma powder synthesis system, and several properties were improved such as: the morphology, the particle size, structure and optical properties. The result shows that, by applying for plasma method, high purity GaN powder was manufactured; the GaN has a good morphology and a regular spherical shape. The spherical ratio of the GaN powder was more than 95%; The GaN powder can be adjusted with different process parameters to achieve particle size control; The GaN powder has sharp diffraction peak and good crystallinity; The GaN powder has the structure of wurtzite and good luminescent properties.

Structural and luminescence properties of GaN nanowires grown on Si substrate by Au catalyst

The synthesis of hexagonal wurtzite one-dimensional GaN nanowires on Si (111) substrate was investigated using a thermal chemical vapor deposition process. The diameter of the GaN NWs was controlled by varying the growth time using a mixture of GaN powder and gallium metal with the ammonia gas reaction. The grown GaN nanowires exhibited a hexagonal perfect wurtzite structure which has been confirmed by high resolution X-ray diffraction analysis. The morphology and elemental analysis of grown GaN nanowires has been studied by scanning electron microscopy and energy dispersive X-ray analysis. Photoluminescence spectra under the excitation of 244 nm showed a strong near band-edge emission around ~ 372 nm and a broad emission at 450–650 nm related to deep-level defects.

On the Investigations of Chip-on-Board Ultra-Violet Sensor by Screen Printing of GaN Powder

In this work, the characteristics of a chip-on-board screen printed GaN UV sensor was investigated. On the sensing element, GaN powders were obtained through ammonolysis of Ga2O3 at 1000°C under NH3 flow. The UV sensor platform was prepared using soft-lithography method, resulted in patterned circuit board. For the screen printing process, GaN powder is mixed with ethylcellulose/ethanol, subsequently deposited on the electrode pairs. The pure GaN sensor exhibited oscillations and change in amplitude upon UV sensing. This could be ascribed to high intrinsic resistance and parasitic capacitance and inductance. To mitigate this effect, rGO fillers were added and showed discern responds. Both sensors (with and without rGO) showed sensitiviy at 300 and 30% respectively, while the current magnitude for the latter was 54 times higher than that of former.

Preparation of gallium nitride from gallium–magnesium alloy powders

Ga–Mg alloy powders were introduced to synthesise GaN powders with flowing ammonia. When the magnesium percentage in the alloy was 25 wt-% or below and the reaction temperature was about 750°C, all Ga atoms in the alloy were transformed into GaN, and the diameter of the GaN powders was about 40 nm. For the Ga–Mg alloy powders with a diameter ranging from 37 to 75 µm ammoniated at 750°C, only 3 h were spent to transform all the Ga atoms into GaN, indicating that the strategy suggested in this study was effective to produce GaN powders.

Crystalline and luminescence changes due to nitridation of undoped GaN powders obtained by pyrolysis from an organometallic complex

Unannealed GaN material was synthesized by pyrolysis from an organometallic complex, where after a nitridation process at 1000 °C in ammonia flow during 2 h, undoped GaN powders were obtained. X-ray diffraction pattern and Raman spectrum for unannealed GaN material did not show well-defined peaks. After the nitridation process, x-ray diffraction pattern and Raman spectrum, demonstrated defined peaks with reflection planes and vibration modes, characteristics of hexagonal GaN. Scanning electron microscopy showed an amorphous superficial morphology for both materials. On the other hand, energy dispersive spectroscopy showed a higher elemental contribution of oxygen for unannealed GaN material, with respect to undoped GaN powders. Photoluminescence spectrum for unannealed GaN material only showed an energy emission band at 1.8 eV (688 nm), while photoluminescence spectrum for undoped GaN powders demonstrated an emission with a maximum energy of 3.44 eV (360 nm), which was associated to the band-to-band transition for the hexagonal GaN.

Catalytic Oxidative Dehydrogenation of n‐Butane on Gallium Nitride‐Containing Titanosilicate Catalyst

GaN‐containing titanosilicate catalysts were used for the first time for the oxidative dehydrogenation (ODH) of n‐butane at a relatively low reaction temperature (460 °C). Commercially available GaN powder with a wurtzite crystal structure showed superior reactivity and stability for the ODH of n‐butane. The catalytic property of GaN catalyst for ODH strongly depends on the GaN particle size. The effects of the GaN weight percentage and GaN particle size on the catalytic performance are investigated in a fixed bed reactor. Based on the physicochemical properties of the catalyst characterized via TEM, DLS, N2 adsorption‐desorption, XRF, O2‐TPD, XRD, XPS, and in‐situ FTIR, the textural and structural properties of catalyst were obtained. The catalytic results reveal that the presence of GaN increases the activity of the catalysts, indicating that GaN can be used as a new active phase for the ODH of n‐butane. XRD, XPS, O2‐TPD, DLS, TEM, and in‐situ FTIR results show that activated O species exist on the surface of the GaN catalyst and enhance the catalytic performance with a decreasing GaN particle size, suggesting that smaller GaN particles possess a remarkable capability to activate O species in O2 and C‐H bonds in light alkanes.

Hexagonal Nanocrystals into AlGaN Powders Obtained via Pyrolysis from an Organometallic Compound

Hexagonal nanocrystals into Al0.2Ga0.8N and Al0.6Ga0.4N powders via pyrolysis from an organometallic compound, followed by a nitridation process in ammonia flow at 1000 °C for two hours were obtained. X-ray diffraction patterns demonstrated a shift towards greater angles to the right for the AlGaN powders with respect to GaN powders, this shift could indicate the formation of the AlGaN powders. Scanning electron microscopy micrographs showed the obtaining from semi-plates of porous appearance for the Al0.2Ga0.8N powders until well-defined plates for the Al0.6Ga0.4N powders. High resolution transmission electron microscopy micrographs demonstrated the presence of hexagonal nanocrystals into Al0.2Ga0.8N powders with an average crystal size of 10.3 nm, while that for the Al0.6Ga0.4N powders an average crystal size of 9.7 nm was observed. UV-visible spectra showed a transmittance cut-off for the Al0.2Ga0.8N powders of 3.71 eV (334.2 nm) and a transmittance cut-off of 4.53 eV (273.7 nm) for the Al0.6Ga0.4N powders.

Hexagonal Nanocrystals into AlGaN Powders Obtained via Pyrolysis from an Organometallic Compound

Hexagonal nanocrystals into Al0.2Ga0.8N and Al0.6Ga0.4N powders via pyrolysis from an organometallic compound, followed by a nitridation process in ammonia flow at 1000 °C for two hours were obtained. X-ray diffraction patterns demonstrated a shift towards greater angles to the right for the AlGaN powders with respect to GaN powders, this shift could indicate the formation of the AlGaN powders. Scanning electron microscopy micrographs showed the obtaining from semi-plates of porous appearance for the Al0.2Ga0.8N powders until well-defined plates for the Al0.6Ga0.4N powders. High resolution transmission electron microscopy micrographs demonstrated the presence of hexagonal nanocrystals into Al0.2Ga0.8N powders with an average crystal size of 10.3 nm, while that for the Al0.6Ga0.4N powders an average crystal size of 9.7 nm was observed. UV-visible spectra showed a transmittance cut-off for the Al0.2Ga0.8N powders of 3.71 eV (334.2 nm) and a transmittance cut-off of 4.53 eV (273.7 nm) for the Al0.6Ga0.4N powders.

Structural and Optical Changes of Undoped GaN Layers Grown via Radio-frequency Magnetron Sputtering Obtained from GaN Powders

Undoped GaN layers were grown via radio-frequency magnetron sputtering, using a target manufactured with undoped GaN powders. Where the GaN powders were sintetized by nitridation of metallic gallium at 1000 °C in ammonia flow for two hours. X-ray diffraction patterns demonstrated that there are not a significant difference between the diffraction angles of the GaN powders and the GaN layers. The x-ray diffraction patterns for the GaN powders showed narrow peaks with a crystal size of 41 nm, while the GaN layers showed broad peaks with a crystal size of 7.7 nm. Scanning electron microscopy micrographs demonstrated the formation of crystals of irregular size with an average length of 1.56 μm for the GaN powders, while a homogeneous surface morphology with a thickness of 6.6 μm for the GaN layers was observed. Photoluminescence spectra showed a high emission at 3.49 eV (355.13 nm) for the GaN powders and an emission band energy located at 3.42 eV (361.54 nm) for the GaN layers, both emission bands were related to the band-to-band transition for the GaN. Raman spectra for the GaN powders showed the A1(TO), E1(TO), and E2(High) classical vibration modes. The GaN layers only showed the A1(TO) mode.

Structural and Optical Changes of Undoped GaN Layers Grown via Radio-frequency Magnetron Sputtering Obtained from GaN Powders

Undoped GaN layers were grown via radio-frequency magnetron sputtering, using a target manufactured with undoped GaN powders. Where the GaN powders were sintetized by nitridation of metallic gallium at 1000 °C in ammonia flow for two hours. X-ray diffraction patterns demonstrated that there are not a significant difference between the diffraction angles of the GaN powders and the GaN layers. The x-ray diffraction patterns for the GaN powders showed narrow peaks with a crystal size of 41 nm, while the GaN layers showed broad peaks with a crystal size of 7.7 nm. Scanning electron microscopy micrographs demonstrated the formation of crystals of irregular size with an average length of 1.56 ?m for the GaN powders, while a homogeneous surface morphology with a thickness of 6.6 ?m for the GaN layers was observed. Photoluminescence spectra showed a high emission at 3.49 eV (355.13 nm) for the GaN powders and an emission band energy located at 3.42 eV (361.54 nm) for the GaN layers, both emission bands were related to the band-to-band transition for the GaN. Raman spectra for the GaN powders showed the A1(TO), E1(TO), and E2(High) classical vibration modes. The GaN layers only showed the A1(TO) mode.

Synthesis and Optical Property of GaN Powder Using an Ultrasonic Spray Pyrolysis Process and Subsequent Nitridation Treatment

Synthesis and Optical Property of GaN Powder Using an Ultrasonic Spray Pyrolysis Process and Subsequent Nitridation Treatment

Zinc doping of Ga-rich GaN powders obtained by nitridation of the Ga-Zn liquid metallic solution

Zn-doped GaN powders were obtained by supersaturation of the Ga-Zn liquid metallic solution at 440 °C, followed by a nitridation process in ammonia flow at 1000 °C for two hours. Photoluminescence spectrum measured at room temperature for Zn-doped GaN powders, showed an emission band with a maximum energy of 2.89 eV (429 nm), which might be related to the excitons binding to the Zn acceptors. The Raman spectra agree with the incorporation of Zn as dopant into GaN powders, demonstrating a shoulder at 651.89 cm−1 and a slight shift (1.55 cm−1) to low frequency of the vibration mode A1(TO) with respect to undoped GaN powders. The Raman spectra showed a separation between the E1(TO) and E2(High) modes, confirming that Ga-rich GaN was obtained. X-ray diffraction patterns did not show any shift of the peaks of the Zn-doped GaN with respect to the undoped GaN powders. Scanning electron microscopy micrographs demonstrated that the surface morphology of the Zn-doped GaN powders was composed of platelets of irregular structure with an average length of 2.80 μm. Finally, x-ray photo-electron spectroscopy spectra did not show an important elemental contribution of zinc due to the small amount of the dopant element (1.05 mol%).