Peroxisome proliferator-activated receptor α activation attenuates the inflammatory response to protect the liver from acute failure by promoting the autophagy pathway

Peroxisome proliferator-activated receptor α (PPARα) has been reported to induce a potent anti-inflammatory response. Autophagy is a recently recognized rudimentary cellular response to inflammation and injury. The aim of the present study was to test the hypothesis that PPARα activation mediates autophagy to inhibit liver inflammation and protect against acute liver failure (ALF). PPARα expression during ALF and the impact of PPARα activation by Wy-14 643 on the hepatic immune response were studied in a D-galactosamine/lipopolysaccharide-induced mouse model. Autophagy was inhibited by 3-methyladenine or small interfering RNA (siRNA) against Atg7. In both the mouse model and human ALF subjects, PPARα was significantly downregulated in the injured liver. PPARα activation by pretreatment with Wy-14 643 protected against liver injury in mice. The protective effect of PPARα activation relied on the suppression of inflammatory mechanisms through the induction of autophagy. This hypothesis is supported by the following evidence: first, PPARα activation suppressed proinflammatory responses and inhibited phosphorylated NF-κBp65, phosphorylated JNK and phosphorylated ERK pathways in vivo. Second, protection by PPARα activation was due to the induction of autophagy because inhibition of autophagy by 3-methyladenine or Atg7 siRNA reversed liver protection and inflammation. Third, PPARα activation directly induced autophagy in primary macrophages in vitro, which protected cells from a lipopolysaccharide-induced proinflammatory response. Here, for the first time, we have demonstrated that PPARα-mediated induction of autophagy ameliorated liver injury in cases of ALF by attenuating inflammatory responses, indicating a potential therapeutic application for ALF treatment.

Elevated plasma sphingomyelin (d18:1/22:0) is closely related to hepatic steatosis in patients with chronic hepatitis C virus infection

Hepatic steatosis affects disease progression in patients with chronic hepatitis C virus (HCV) infection. We investigated the plasma sphingolipid profile in patients with chronic hepatitis C (CHC) and whether there was an association between HCV-related steatosis and plasma sphingolipids. We used high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) to analyze plasma sphingolipids in 120 interferon-naïve, non-diabetic, and non-obese CHC patients. Hepatic steatosis was defined as ≥5 % hepatocytes with fat based on histopathological analysis. Blood biochemical indicators and HCV load and genotype were also determined. Thirty-six (30.0 %) of 120 patients presented with hepatic steatosis Grades 1-3. Forty-four plasma sphingolipids were detected. Plasma sphingomyelin (SM) (d18:1/22:0) and ceramide (Cer) (d18:1/24:0)-1-P correlated with steatosis grade (r = 0.22, p = 0.015; r = -0.23, p = 0.012, respectively). SM (d18:1/22:0) [odds ratio (OR) = 1.12] and Cer (d18:1/24:0)-1-P (OR = 0.88) were independent factors for the presence of hepatic steatosis in CHC patients. The area under the curve (AUC) of SM (d18:1/22:0) and Cer (d18:1/24:0)-1-P was 0.637 and 0.638, respectively, to identify the presence of steatosis. Further analysis for genotype 2 CHC showed that only SM (d18:1/22:0) was independently linked to steatosis (OR = 1.21). The AUC of SM (d18:1/22:0) to identify hepatic steatosis in genotype 2 CHC was 0.726. Its sensitivity and negative predictive value reached 0.813 and 0.886, respectively. This study suggested that altered plasma SM (d18:1/22:0) was closely related to hepatic steatosis in chronic HCV infection, especially with genotype 2. Experimental studies are needed to determine further the underlying mechanisms responsible for these associations.

Band offsets in YSZ/InGaZnO4 heterostructure system

The energy discontinuity in the valence band (deltaE(v)) of Y2O3-stabilized ZrO2 (YSZ)/InGaZnO4 (IGZO) heterostructures was obtained from X-ray photoelectron spectroscopy (XPS) measurements. The YSZ exhibited a bandgap of 4.4 eV from absorption measurements. A value of deltaE(v) = 0.57 +/- 0.12 eV was obtained by using Ga 2P3/2, Zn 2p3/2 and In 3d5/2 energy levels as references. This implies a conduction band offset (deltaE(c)) of 0.63 eV in YSZ/InGaZnO4 heterostructures and a nested interface band alignment.

Lactobacillus salivarius Ren prevent the early colorectal carcinogenesis in 1, 2-dimethylhydrazine-induced rat model

AIMS

The objective of this study was to investigate the impact of Lactobacillus salivarius Ren (LS) on modulating colonic micro flora structure and influencing host colonic health in a rat model with colorectal precancerous lesions.

METHODS AND RESULTS

Male F344 rats were injected with 1, 2-dimethylhydrazine (DMH) and treated with LS of two doses (5 × 10(8) and 1 × 10(10) CFU kg(-1) body weight) for 15 weeks. The colonic microflora profiles, luminal metabolites, epithelial proliferation and precancerous lesions [aberrant crypt foci (ACF)] were determined. A distinct segregation of colonic microflora structures was observed in LS-treated group. The abundance of one Prevotella-related strain was increased, and the abundance of one Bacillus-related strain was decreased by LS treatment. These changes were accompanied by increased short-chain fatty acid levels and decreased azoreductase activity. LS treatment also reduced the number of ACF by c. 40% and suppressed epithelial proliferation.

CONCLUSIONS

Lactobacillus salivarius Ren improved the colonic microflora structures and the luminal metabolisms in addition preventing the early colorectal carcinogenesis in DMH-induced rat model.

SIGNIFICANCE AND IMPACT OF THE STUDY

Colonic microflora is an important factor in colorectal carcinogenesis. Modulating the structural shifts of microflora may provide a novel option for preventing colorectal carcinogenesis. This study suggested a potential probiotic-based approach to modulate the intestinal microflora in the prevention of colorectal carcinogenesis.

In situ Raman scattering study on a controllable plasmon-driven surface catalysis reaction on Ag nanoparticle arrays

Control of the plasmon-driven chemical reaction for the transformation of 4-nitrobenzenethiol to p,p'-dimercaptoazobenzene by Ag nanoparticle arrays was studied. The Ag nanoparticle arrays were fabricated by means of nanosphere lithography. By changing the PS particle size, the localized surface plasmon resonance (LSPR) peaks of the Ag nanoparticle arrays can be tailored from 460 to 560 nm. The controlled reaction process was monitored by in situ surface-enhanced Raman scattering. The reaction can be dramatically influenced by varying the duration of laser exposure, Ag nanoparticle size, laser power and laser excitation wavelength. The maximum reaction speed was achieved when the LSPR wavelength of the Ag nanoparticle arrays matched the laser excitation wavelength. The experimental results reveal that the strong LSPR can effectively drive the transfer of the 'hot' electrons that decay from the plasmon to the reactants. The experimental results were confirmed by theoretical calculations.

Ion Milling and Reactive Ion Etching of III-V Nitrides

Dry patterning of GaN, InN, AlN and InGaN grown by MOMBE on GaP, Al2 O3 or GaAs substrates was performed with 100–500 eV Ar+ ions at beam angles of incidence ranging from 0–75° from the normal, or with ECR discharges of BCl3/Ar, CH4/H2 or Cl2/H2. The mill rates normalized to the Ar+ beam current were typically a factor of 2 lower than for GaAs and InP (i.e. maximum values of 300–500 Å·min-1·mA-1·cm-2 at 400eV Ar+ beam energy and 60° angle with respect to the beam normal). The surface morphology of the ion milled nitrides was smooth even at 500 eV Ar+ energy, with no evidence for preferential sputtering of N as determined by AES. The ECR dry etch rates were fastest with elevated temperature Cl2/H2discharges, although both of the other chemistries investigated provide smooth, anisotropie pattern transfer. Since the ion mill rates are slow for single-crystal nitrides and less than the mill rates of common masking materials (SiO2, SiNx, photoresist) it appears this technique is useful only for shallow-mesa applications, and that dry etching methods involving an additional chemical component or ion implantation isolation are more practical alternatives for device patterning.

Dielectrics for GaN Based MIS-Diodes

GaN MIS diodes were demonstrated utilizing AIN and Ga2O3(Gd2O3) as insulators. A 345 Åof AIN was grown on the MOCVD grown n-GaN in a MOMBE system using trimethylamine alane as Al precursor and nitrogen generated from a wavemat ECR N2 plasma. For the Ga2O3(Gd2O3) growth, a multi-MBE chamber was used and a 195 Å oxide is E-beam evaporated from a single crystal source of Ga5Gd3O12. The forward breakdown voltage of AlN and Ga2O3( Gd2O3) diodes are 5V and 6V, respectively, which are significantly improved from ˜1.2 V of schottky contact. From the C-V measurements, both kinds of diodes showed good charge modulation from ccumulation to depletion at different frequencies. The insulator/GaN interface roughness and the thickness of the insulator were measured with x-ray reflectivity.

Ecr Etching of GaP, GaAs, InP, and InGaAs in Cl2/Ar, Cl2/N2, BCl3/Ar, and BCl3/N2

Electron cyclotron resonance (ECR) etching of GaP, GaAs, InP, and InGaAs are reported as a function of percent chlorine-containing gas for Cl2/Ar, Cl2/N2, BCl3/Ar, and BCl3/N2 plasma chemistries. GaAs and GaP etch rates were faster than InP and InGaAs, independent of plasma chemistry due to the low volatility of the InClx, etch products. GaAs and GaP etch rates increased as %Cl2 was increased for Cl2/Ar and Cl2/N2 plasmas. The GaAs and GaP etch rates were much slower in BCl3-based plasmas due to lower concentrations of reactive Cl, however enhanced etch rates were observed in BCl3/N2 at 75% BCl3. Smooth etched surfaces were obtained over a wide range of plasma chemistries.

Development of Low Temperature Silicon Nitride and Silicon Dioxide Films by Inductively-Coupled Plasma Chemical Vapor Deposition

High-density plasma technology is becoming increasingly attractive for the deposition of dielectric films such as silicon nitride and silicon dioxide. In particular, inductively-coupled plasma chemical vapor deposition (ICPCVD) offers a great advantage for low temperature processing over plasma-enhanced chemical vapor deposition (PECVD) for a range of devices including compound semiconductors. In this paper, the development of low temperature (< 200°C) silicon nitride and silicon dioxide films utilizing ICP technology will be discussed. The material properties of these films have been investigated as a function of ICP source power, rf chuck power, chamber pressure, gas chemistry, and temperature. The ICPCVD films will be compared to PECVD films in terms of wet etch rate, stress, and other film characteristics. Two different gas chemistries, SiH4/N2/Ar and SiH4/NH3/He, were explored for the deposition of ICPCVD silicon nitride. The ICPCVD silicon dioxide films were prepared from SiH4/O2/Ar. The wet etch rates of both silicon nitride and silicon dioxide films are significantly lower than films prepared by conventional PECVD. This implies that ICPCVD films prepared at these low temperatures are of higher quality. The advanced ICPCVD technology can also be used for efficient void-free filling of high aspect ratio (3:1) sub-micron trenches.

High-Density Plasma-Induced Etch Damage of GaN

Anisotropic, smooth etching of the group-Ill nitrides has been reported at relatively high rates in high-density plasma etch systems. However, such etch results are often obtained under high dc-bias and/or high plasma flux conditions where plasma induced damage can be significant. Despite the fact that the group-III nitrides have higher bonding energies than more conventional III–V compounds, plasma-induced etch damage is still a concern. Attempts to minimize such damage by reducing the ion energy or increasing the chemical activity in the plasma often result in a loss of etch rate or anisotropy which significantly limits critical dimensions and reduces the utility of the process for device applications requiring vertical etch profiles. It is therefore necessary to develop plasma etch processes which couple anisotropy for critical dimension and sidewall profile control and high etch rates with low-damage for optimum device performance. In this study we report changes in sheet resistance and contact resistance for n- and p-type GaN samples exposed to an Ar inductively coupled plasma (ICP). In general, plasma-induced damage was more sensitive to ion bombardment energies as compared to plasma flux. In addition, p-GaN was typically more sensitive to plasma-induced damage as compared to n-GaN.

Wet Chemical Etching Survey Of III-Nitrides

Wet chemical etching of GaN, InN, AIN, InAlN and InGaN was investigated in various acid and base solutions at temperatures up to 75°C. Only KOH-based solutions were found to etch AIN and InAlN. No etchants were found for the other nitrides, emphasizing their extreme lack of chemical reactivity. The native oxide on most of the nitrides could be removed in potassium tetraborate at 75°C, or HCl/H2O at 25°C.

AlGaN/GaN Structures Grown by HVPE: Growth and Characterization

This letter reports on multi-layer submicron epitaxial device structures grown by hydride vapor phase epitaxy (HVPE). This is the first demonstration of both high electron mobility transistor (HEMT) devices and ultraviolet light emitting diodes (LED) emitting in the wavelength range from 305 to 340 nm based on AlGaN/GaN and AlGaN/AlGaN heterostructures grown by HVPE. Two unique aspects of this technological approach are the growth of Al-containing epitaxial material by HVPE and use of HVPE to form submicron multi-layer epitaxial structures. The high performance of HVPE grown devices presented in this report demonstrates the significant potential that exists for HVPE growth technology for mass production of device epitaxial wafers.

Comparative serum proteomic analysis of patients with acute-on-chronic liver failure: alpha-1-acid glycoprotein maybe a candidate marker for prognosis of hepatitis B virus infection

The acute-on-chronic liver failure (AoCLF) caused by hepatitis B virus (HBV) infection remains to be a challenge in clinics with a high mortality rate in China, and it is important to identify biomarkers to foresee the prognosis of patients with HBV. The current study analysed serum proteome changes of acute-on-chronic liver failure as a result of acute exacerbation of chronic hepatitis B infection. Serum samples were collected from normal subjects (NS, n = 8), patients with chronic hepatitis B (CHB, n = 12) and patients with AoCLF (n = 12). After removal of albumin/IgG and ultramembrane centrifugation, serum proteins were separated by two-dimensional gel electrophoresis. Differentially expressed spots were identified by matrix-associated laser desorption ionization time-of-flight tandem mass spectrometry. Through the removal of albumin/IgG and ultramembrane centrifugation, the well-resolved and reproducible two-dimensional gel electrophoresis (2-DE) profiles were obtained. A total of 23 proteins were identified on 2-DE profiles by their differential expression between the three cohorts. Mass spectrometry analysis resulted in the identification of 12 proteins unambiguously. Western blot analysis confirmed the proteomics results that the α1-acid glycoprotein (α1-AGP) levels decrease significantly in plasma of patients with AoCLF, but somewhat decreased in patients with chronic HBV. Further α1-AGP levels in bulk serum samples were measured by immune turbidimetry including normal subjects group (n = 25), acute hepatitis group (n = 36), chronic hepatitis group (n = 52) and AoCLF group (n = 48), the level of α1-AGP in AoCLF groups sharply decrease than other groups. Our study shows that α1-AGP may be a potential plasma biomarker for AoCLF diagnosis because of acute exacerbation of chronic hepatitis B infection.

Antibacterial silver-containing silica glass prepared by ion implantation

Recently, there is much interest in nanocomposites consisting of metal nanoparticles dispersed in dielectric matrix. Silver is the first candidate used in antibacterial research. In the present study, sliver-containing silica glass is prepared by ion implantation. The bactericidal properties of Ag-implanted samples are investigated using E. coli. The implanted samples are characterized by optical absorption spectroscopy, atomic force microscopy and transmission electron microscopy. The size and position of the silver nanoparticles formed by ion implantation can be optimized by adjusting the implanted process parameters. All the implanted samples show antibacterial properties. But the samples with silver nanoparticle-enriched surfaces possess excellent antibacterial properties in comparison with other implanted samples. This indicates that ion implantation is a potential method for synthesizing antibacterial biomaterials.

Caspase-8 and p38MAPK in DATS-induced apoptosis of human CNE2 cells

Nasopharyngeal carcinoma is a common malignancy in Southern China of uncertain etiologic origin. Diallyl trisulfide (DATS), one of the major components of garlic (Allium sativum), is highly bactericidal and fungicidal. In this study, we investigated the function of p38 mitogen-activated protein kinase (MAPK) and caspase-8 in DATS-induced apoptosis of human CNE2 cells using MTT [3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide], flow cytometry assay, and Western blotting. After CNE2 cells were treated with DATS (50, 100, or 150 μM) for 24 h, cell viability rates were 75.9, 63.4 and 39.6%, and apoptosis rates were 24.5, 36.9, and 62.4%, respectively. The data showed that DATS induced CNE2 cell death in a dose-dependent manner. After human CNE2 cells were treated with 100 μM DATS and inhibitors (10 μM SB203580 and Z-LETD-FMK for p38MAPK and caspase-8, respectively), changes in cell viability and apoptosis and in p38MAPK and caspase-8 activity were detected. Cell viability rates were 66.5 and 68.1% and decreased 9.9 and 11.5% compared with inhibitor treatment alone. Apoptosis rates were 31.53 and 29.98% and increased 9.1 and 10% compared with inhibitor treatment alone. The results indicated that DATS activates p38MAPK and caspase-8, but both inhibitors have an effect on P38MAPK and caspase-8 activity. In conclusion, our data indicate that p38MAPK and caspase-8 are involved in the process of DATS-induced apoptosis in human CNE2 cells and interact with each other.

Synthesis, characterization and ab initio simulation of magnesium-substituted hydroxyapatite

The substitution of magnesium in hydroxyapatite (HA) was examined in HA nano-crystals synthesized by the wet-chemical precipitation method at 90 degrees C. Comprehensive characterization techniques, including X-ray diffraction, X-ray fluorescence, field emission scanning electron microscopy, high-resolution transmission electron microscopy, thermogravimetric analysis and Rietveld refinement, provided experimental evidence of the effects of Mg substitution on the phase, crystallinity, chemical composition, crystal size, morphology, thermal stability and crystal lattice structure of HA. A computational study using ab initio generalized gradient approximation density functional theory was performed to reveal changes in lattice parameters and preferential calcium sites for Mg substitution in HA. The experimental results showed that a limited amount of Mg (Mg/(Mg+Ca) between 5 and 7 mol.%) could successfully substitute for Ca in HA. HA crystallites became smaller and more irregular, and they formed greater agglomerates with Mg substitution. Mg substitution resulted in decreases in the crystallinity and thermal stability of HA. The lattice constants, a and c, decreased with increasing Mg substitution. The simulation results revealed that the Ca(1) sites in HA lattices were energetically favored sites for Mg substitution.

Synthesis and Magnetic Properties of Maghemite (gamma-Fe(2)O(3)) Short-Nanotubes

We report a rational synthesis of maghemite (gamma-Fe(2)O(3)) short-nanotubes (SNTs) by a convenient hydrothermal method and subsequent annealing process. The structure, shape, and magnetic properties of the SNTs were investigated. Room-temperature and low-temperature magnetic measurements show that the as-fabricated gamma-Fe(2)O(3) SNTs are ferromagnetic, and its coercivity is nonzero when the temperature above blocking temperature (T(B)). The hysteresis loop was operated to show that the magnetic properties of gamma-Fe(2)O(3) SNTs are strongly influenced by the morphology of the crystal. The unique magnetic behaviors were interpreted by the competition of the demagnetization energy of quasi-one-dimensional nanostructures and the magnetocrystalline anisotropy energy of particles in SNTs.