Cluster Formation in Laser-Induced Ablation and Evaporation of Solids Observed by Laser Ionization Time-Offlight Mass-Spectrometry and Scanning Tunneling Microscopy

Laser ionization time-of-flight mass analysis (LIMA) used pulses (5ns) of a frequency- quadrupled Nd-YAG laser (266 nm) focused onto spots of 4–100 μm diameter to ablate material, and a reflectron time of flight tube to mass-analyze the plume. The observed mass spectra for Si, Pt, SiC, and UO2 varied in the distribution of ablation products among atoms, molecules and clusters, depending on laser power density and target material.

Cleaved surfaces of highly oriented pyrolytic graphite (HOPG) positioned at room temperature either 10 cm away from materials ablated at 10−5 Torr by 1–3 excimer laser (308 nm) pulses of 20 ns duration or 1 m away from materials vaporized at 10−8 Torr by 10 Nd-Glass laser pulses of 1 ms duration were analyzed by Scanning Tunneling Microscopy (STM) in air with Ångstrom resolution. Clusters up to 30 Å in diameter were observed.

Heating, Laser Irradiation and Passivation Study on the Light-Emitting Porous Silicon

For light-emitting porous Si there has been a severe problem with instability and degradation of the light emission. We report that a stabilization of the emission intensity and the peak energy can be achieved in air by a proper laser irradiation, In-situ photoluminescence measurements were performed to monitor the degradation and stabilization process under different conditions and parameters, such as laser power, laser wavelength and environment (ambient atmosphere of certain gas or ultra high vacuum). We found oxygen is the major cause for the emission degradation in this laser enhanced adsorption process, and the laser heating effect can be excluded. For a comparison we study the reversible thermal heating and quenching process. We also discuss microwave and ECR plasma passivation results.

Light-Emitting Porous Silicon in High Magnetic Fields

Photoluminescence from porous silicon was studied in a helium atmosphere and at high magnetic fields. In a magnetic field, the spectral peak had a negligible shift, amounting to +0.2 ±0.5 meV at B= 18T. If quantum confinement is the major effect, then the conduction electron would be confined to a diameter of less than 3.5 nm.

Oxidation Resistant Dilute Copper (Boron) Alloy Films Prepared by DC-Magnetron Cosputtering

To enhance the corrosion resistance and reliability of the proposed copper interconnections in silicon integrated circuits, alloying with small amounts thermodynamically favorable elements has been pursued. In the present investigation dilute copper (boron) alloy thin films (in boron concentration range of 0-4 at % in copper) were deposited by DC magnetron co-sputtering using a high purity copper and Cu-4 at % B targets. Films were then annealed in Ar-3% H2, pure Ar, vacuum, and air ambients in the temperature range of 200–500°C. Sheet resistance, Rutherford backscattering, x-ray diffraction measurements were made to characterize the films. The residual resistivity of the as-deposited alloy films was found to be 5.3 μΩ-cm/at %. To obtain sufficiently low working resistivity, an alloy content below 0.5 at % is suggested for application as a potential “metallization material. The addition of boron, which is the common dopant in Si, to the copper films offers considerable oxidation protection. The resulting oxidation rates are considerably lower than that for pure copper films. All this will be presented and discussed.

Characterization of a novel HLA allele, HLA-B*40:128, in a Chinese individual

Nucleotide sequence of HLA-B*40:128 has a single nucleotide difference at position 539 T>G compared with that of HLA-B*40:01:01, with an amino acid change from Leu to Arg at codon 156.

Co-adjuvant effects of retinoic acid and IL-15 induce inflammatory immunity to dietary antigens

Under physiological conditions the gut-associated lymphoid tissues not only prevent the induction of a local inflammatory immune response, but also induce systemic tolerance to fed antigens. A notable exception is coeliac disease, where genetically susceptible individuals expressing human leukocyte antigen (HLA) HLA-DQ2 or HLA-DQ8 molecules develop inflammatory T-cell and antibody responses against dietary gluten, a protein present in wheat. The mechanisms underlying this dysregulated mucosal immune response to a soluble antigen have not been identified. Retinoic acid, a metabolite of vitamin A, has been shown to have a critical role in the induction of intestinal regulatory responses. Here we find in mice that in conjunction with IL-15, a cytokine greatly upregulated in the gut of coeliac disease patients, retinoic acid rapidly activates dendritic cells to induce JNK (also known as MAPK8) phosphorylation and release the proinflammatory cytokines IL-12p70 and IL-23. As a result, in a stressed intestinal environment, retinoic acid acted as an adjuvant that promoted rather than prevented inflammatory cellular and humoral responses to fed antigen. Altogether, these findings reveal an unexpected role for retinoic acid and IL-15 in the abrogation of tolerance to dietary antigens.

Bandtail Limits to Solar Conversion Efficiencies in Amorphous Silicon Solar Cells

We describe a model for a-Si:H based pin solar cells derived primarily from valence bandtail properties. We show how hole drift-mobility measurements and measurements of the temperature-dependence of the open-circuit voltage VOC can be used to estimate the parameters, and we present VOC(T) measurements. We compared the power density under solar illumination calculated with this model with published results for as-deposited a-Si:H solar cells. The agreement is within 4% for a range of thicknesses, suggesting that the power from as-deposited cells is close to the bandtail limit.

Tissue-specific dysregulation of hexose-6-phosphate dehydrogenase and glucose-6-phosphate transporter production in db/db mice as a model of type 2 diabetes

AIMS/HYPOTHESIS

Tissue-specific amplification of glucocorticoid action through 11β-hydroxysteroid dehydrogenase type 1 (11β-HSD1) affects the development of the metabolic syndrome. Hexose-6-phosphate dehydrogenase (H6PDH) mediates intracellular NADPH availability for 11β-HSD1 and depends on the glucose-6-phosphate transporter (G6PT). Little is known about the tissue-specific alterations of H6PDH and G6PT and their contributions to local glucocorticoid action in db/db mice.

METHODS

We characterised the role of H6PDH and G6PT in pre-receptor metabolism of glucocorticoids by examining the production of the hepatic 11β-HSD1-H6PDH-G6PT system in db/db mice.

RESULTS

We observed that increased production of hepatic H6PDH in db/db mice was paralleled by upregulation of hepatic G6PT production and responded to elevated circulating levels of corticosterone. Treatment of db/db mice with the glucocorticoid antagonist RU486 markedly reduced production of both H6PDH and 11β-HSD1 and improved hyperglycaemia and insulin resistance. The reduction of H6PDH and 11β-HSD1 production by RU486 was accompanied by RU486-induced suppression of hepatic G6pt (also known as Slc37a4) mRNA. Incubation of mouse primary hepatocytes with corticosterone enhanced G6PT and H6PDH production with corresponding activation of 11β-HSD1 and PEPCK: effects that were blocked by RU486. Knockdown of H6pd by small interfering RNA showed effects comparable with those of RU486 for attenuating the corticosterone-induced H6PDH production and 11ß-HSD1 reductase activity in these intact cells. Addition of the G6PT inhibitor chlorogenic acid to primary hepatocytes suppressed H6PDH production.

CONCLUSIONS/INTERPRETATION

These findings suggest that increased hepatic H6PDH and G6PT production contribute to 11β-HSD1 upregulation of local glucocorticoid action that may be related to the development of type 2 diabetes.

Comparison of the 6th and 7th editions of the UICC TNM staging system for gastric cancer: Results of a Chinese single-institution study of 1,503 patients

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Background: To evaluate the prognostic efficacy of the 7th edition TNM classification compared to the 6th edition in gastric cancer patients.

Methods: A total of 1,503 gastric cancer patients undergoing surgical resection were staged using the 6th and 7th edition staging systems. Homogeneity, discriminatory ability, and monotonicity of gradients of the two systems were compared using linear trend X2, likelihood ratio X2 statistics, and Akaike information criterion (AIC) calculations.

Results: Significant differences in five-year survival rates were observed for the “T,” “N,” and “M” subgroups using the 7th edition system, except for stage N2 and N3 patients in the 6th edition system. There were no significant differences in survival between IB and IIA in the 7th edition system. Patients with stage IV disease due to T4/N3 in the 6th edition system who were downstaged to stage III in the 7th edition system had significantly better survival than those who remained at stage IV. The 7th edition system had higher linear trend and likelihood ratio X2 scores, and smaller AIC values compared with those for the 6th edition, which represented the optimum prognostic stratification.

Conclusions: Our study suggested that the 7th edition system performs superior to the 6th edition in several aspects.

No significant financial relationships to disclose.

Engagement of activated Notch signalling in collagen II-specific T helper type 1 (Th1)- and Th17-type expansion involving Notch3 and Delta-like1

Our previous study demonstrated that T helper (Th) cells from patients with rheumatoid arthritis (RA) display an altered expression profile of Notch receptors and enhanced activation of Notch signalling. The aim of this study was to investigate the role of distinct Notch receptors and ligands in the activation and differentiation of collagen II (CII)-reactive Th cells upon antigen-specific restimulation. Spleen mononuclear cells (SMNCs) from CII-immunized DBA/1J mice were restimulated by culturing with CII. CII-specific proliferation and differentiation of T cells were determined by tritiated thymidine ((3) [H]-TdR) incorporation and flow cytometric analysis, respectively. The mRNA expression of Notch receptors and Hes1 was assessed by real-time polymerase chain reaction (PCR). There was a clear increase in the percentage of Th1 cells and Th17 cells after CII restimulation. No significant difference was observed in the percentage of regulation T cells (T(reg) ) in SMNCs with or without CII restimulation. CII restimulation induced up-regulated transcript levels of Hes1 in CII-reactive CD4(+) T cells. The mRNA level of Notch3 was also up-regulated significantly, while the levels of the other three Notch receptors were not increased. Inhibition of Notch signalling by N-[N-(3,5-difluorophenacetyl)-L-alanyl]-S-phenylglycine t-butyl ester (DAPT) and Notch3 antibody decreased the collagen-specific T cell proliferation and attenuated Th1- and Th17-type responses, while treatment with Notch ligand Delta-like 1 promoted such a response. The present study demonstrates that Notch signalling is engaged in CII-specific Th1- and Th17-type expansion in which Notch3 and Delta-like1 were involved. Selective inhibition of Notch signalling mediated by Notch3 or Delta-like1 may offer a new strategy for the treatment of RA.

Invasive pulmonary aspergillosis in patients with HBV-related liver failure

Invasive pulmonary aspergillosis (IPA) has been increasingly frequent in severe liver disease. We aim to investigate the clinical presentation, predisposing factors, and treatment of IPA in patients with liver failure caused by hepatitis B virus (HBV) infection. Medical records from 798 patients with HBV-related liver failure were reviewed. A total of 43 patients with probable IPA were selected as the case group, another 43 patients with bacterial infection and 43 patients without any infections were selected, for whose age, sex, date of admission, and the disease onset were matched with the case group. We evaluated the risk factors, clinical manifestations, treatment, and subsequent outcome of IPA in patients with HBV-related liver failure. Multivariate logistic regression models were used to demonstrate risk factors associated with IPA. Compared with patients with bacterial infection and those without any infection, patients with probable IPA used more antibiotics and steroids, and had poorer conditions and the highest mortality (P < 0.0001). Multiple antibiotics use and frequent invasive procedures were independent factors associated with the occurrence of IPA in patients with HBV-related liver failure. Patients with HBV-related liver failure are predisposed to IPA and may have a more severe condition and poorer prognosis.

Pharmacokinetics of lipoyl vildagliptin, a novel dipeptidyl peptidase IV inhibitor after oral administration in rats

The pharmacokinetics of lipoyl vildagliptin, a novel dipeptidyl peptidase IV (DPP IV) inhibitor, was studied in rats after oral administration for developing it as an antidiabetic agent. A liquid chromatography-tandem mass spectroscopy (LC-MS/MS) method was developed to determine lipoyl vildagliptin in rat plasma. After an overnight fasting, rats were orally given lipoyl vildagliptin. Following a single oral dose of 25, 50, and 100 mg x kg(-1), T(max) values were from 1.25 to 1.84 h, CL/F values were around 100 l h(-1) kg(-1). In the dose range, C(max) values (63.9-296 μg x l(-1)) and AUC(0-∞)values (260-1214 μg x h x l(-1)) were proportional to the doses. In conclusion, this LC-MS/MS method for the determination of lipoyl vildagliptin in rat plasma was selective and sensitive. In rats, lipoyl vildagliptin displayed linear pharmacokinetics after a single oral dose in the range of 25-100 mg x kg(-1). Lipoyl vildagliptin might have very high CL/F values and V(d)/F values, which indicated that the bioavailability of this drug might be low or lipoyl vildagliptin might distribute extensively or accumulate in tissues in view of its high liposolubility.