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Hepatic steatosis is associated with increased insulin resistance and tricarboxylic acid (TCA) cycle flux, but decreased ketogenesis and pyruvate dehydrogenase complex (PDC) flux. This study examined whether hepatic PDC activation by inhibition of pyruvate dehydrogenase kinase 2 (PDK2) ameliorates these metabolic abnormalities. Wild-type mice fed a high-fat diet exhibited hepatic steatosis, insulin resistance, and increased levels of pyruvate, TCA cycle intermediates, and malonyl-CoA but reduced ketogenesis and PDC activity due to PDK2 induction. Hepatic PDC activation by PDK2 inhibition attenuated hepatic steatosis, improved hepatic insulin sensitivity, reduced hepatic glucose production, increased capacity for β-oxidation and ketogenesis, and decreased the capacity for lipogenesis. These results were attributed to altered enzymatic capacities and a reduction in TCA anaplerosis that limited the availability of oxaloacetate for the TCA cycle, which promoted ketogenesis. The current study reports that increasing hepatic PDC activity by inhibition of PDK2 ameliorates hepatic steatosis and insulin sensitivity by regulating TCA cycle anaplerosis and ketogenesis. The findings suggest PDK2 is a potential therapeutic target for nonalcoholic fatty liver disease.

We recently suggested that alveolar interstitial fibroblast-to-myofibroblast transdifferentiation may be a key mechanism underlying in utero nicotine-induced lung injury. However, the effects of in utero nicotine exposure on fetal alveolar type II (ATII) cells have not been fully determined. Placebo, nicotine (1 mg/kg), or nicotine (1 mg/kg) + the peroxisome proliferator-activated receptor (PPAR)-γ agonist prostaglandin J2 (PGJ2, 0.3 mg/kg) was administered intraperitoneally once daily to time-mated pregnant Sprague-Dawley rats from embryonic day 6 until their death on embryonic day 20. Fetal ATII cells were isolated, and ATII cell proliferation, differentiation (surfactant synthesis), and metabolism (metabolic profiling with the stable isotope [1,2-13C2]-d-glucose) were determined after nicotine exposure in utero or in vitro. In utero nicotine exposure significantly stimulated ATII cell proliferation, differentiation, and metabolism. Although the effects on ATII cell proliferation and metabolism were almost completely prevented by concomitant treatment with PGJ2, the effects on surfactant synthesis were not. On the basis of in utero and in vitro data, we conclude that surfactant synthesis is stimulated by nicotine's direct effect on ATII cells, whereas cell proliferation and metabolism are affected via a paracrine mechanism(s) secondary to its effects on the adepithelial fibroblasts. These data provide evidence for direct and indirect effects of in utero nicotine exposure on fetal ATII cells that could permanently alter the “developmental program” of the developing lung. More importantly, concomitant administration of PPAR-γ agonists can effectively attenuate many of the effects of in utero exposure to nicotine on ATII cells.

Iron impurities in bulk silicon are found to getter efficiently at the polysilicon layer by an electric field during isothermal annealing. Experimental results show that iron concentration at the polysilicon layer increases to the level that becomes detectable by total reflection x-ray fluorescence (TXRF) spectroscopy. The improved gettering efficiency for iron is attributed mainly to the directional drift of ionic iron interstitials toward the polysilicon gettering sites, under the influence of the applied potential gradient, thus presenting a more effective method for reducing the iron content in silicon.

Temperature-dependent direct current (dc) and microwave (mw) conductivity, σdc and σmw, electron paramagnetic resonance (EPR), and mechanical properties of sulfonated polyaniline/poly(p-phenylene terephthalamide) (SPAN/PPD-T) composite fibers are presented. Tenacity and modulus are in the range of 15 and 270 g/denier (gpd), respectively, for 30 wt % (weight percent prior to sulfonation) SPAN composite fiber. Room-temperature dc conductivity σRT varies from 7.8 × 10-5 to 1.5 × 10-1 S/cm, increasing with increasing wt % polyaniline (PAn) and spin stretch factor (SSF). The temperature-dependent conductivity follows the quasi-one-dimensional variable range hopping (Q1D VRH) model: σdc(T) = σ0 exp [−(T0/T)γ], where γ ∼ 0.5 and σ0 is a constant. T0 is 4.3 × 104 to 2.9 × 104 K, respectively, for 10 and 30 wt % PAn. The σmw of the fiber with the same SSF 7.0 but a 30/70 PAn/PPD-T ratio shows a typical temperature dependence for materials for which the hopping conduction mechanism is dominant. There is a larger d...

Highly conducting polymers such as polyaniline and polypyrrole in a dielectrical state have unusually strong temperature of dependence of dynamic conductivity. We argue that this strong temperature dependence is due to the low dimensionality of charge transport in the polymers. The hopping network is formed by fast one-dimensional diffusion along the chains and rare interchain hops. Depending on the chain morphology the network is modeled by a quasi-one-dimensional system of randomly linked chains or by a quasi-one-dimensional chain fractal with dimensionality 1+s, where s≪1. We point out the experimental data for dielectric constant and ac-conductivity that supports these two models.

We report that LiCl dopes the emeraldine base (EB) form of polyaniline and produces polyaniline with unusual properties—polyaniline with doping-induced charge localization. Our assignment of Li+ doping is based upon the observation of electronic states in the bandgap and associated spins for EB processed with LiCl. However, even at the maximum doping level, LiCl-doped polyaniline is a strongly localized charged insulator based on the observation of low DC conductivity, low dielectric constant, rapid decrease of the oscillator strength to zero in the infrared, low magnetic susceptibility dominated by a weak Curie component, broad EPR linewidth and predominantly Gaussian lineshape of the EPR signal. Finally, we attribute these properties to the formation of bipolarons or antiferromagnetically coupled polaron pairs in LiCl-doped EB.

A mathematical model is presented to explain the effect of ultraviolet (UV) irradiation on the minority carrier recombination lifetime (LT) and surface barrier observed in thermally oxidized, RCA cleaned, and contaminated silicon wafers. The proposed model assumes that UV photons (4.9 eV) modify the density of two interface traps and the oxide charge density. It considers the conversion between the two species of traps with energy levels E1 and E2, relative to the intrinsic Fermi level (Ei). These modifications directly affect the surface recombination velocity and hence the effective LT. The changes in the effective lifetime and the surface barrier as a result of UV irradiation as simulated by the model was found to be in good agreement with experimental data.

The minority carrier recombination lifetimes of ultraviolet-irradiated silicon wafers were studied using the laser-microwave photoconductance method. These wafers were intentionally surface contaminated with metals. With ultraviolet irradiation, the effective minority carrier recombination lifetimes of these samples are enhanced. The lifetime enhancement occurs at a faster rate for contaminated wafers. These lifetime enhancements are not permanent; with cessation of the ultraviolet radiation, the preirradiation levels can be restored.

The results of the temperature dependence of dc conductivity, microwave dielectric constant, X-ray diffraction, EPR, and NMR experiments are reported for chemically synthesized polypyrrole films soluble in organic solvents. The temperature dependence of dc conductivity of these systems follows the three-dimensional variable range hopping model. The slope of the temperature dependence of dc conductivity varies with dopants and solvents used. Room temperature dc conductivities are in the range of ∼0.2−0.01 S/cm, and the localization lengths are estimated as ≤10 A, which indicates a relatively strong localization of charge. The results of microwave dielectric constant experiments support the strong localization behavior. The X-ray diffraction studies show that soluble polypyrroles are amorphous. From electron paramagnetic resonance experiments, the density of states of polypyrrole doped with naphthalenesulfonic acid in m-cresol solvent is estimated as ∼0.107 states/(eV ring). We obtain the result that the sy...

Testosterone-induced nitrogen retention in castrated male animals and sex-related differences in the size of the muscles in male and female animals have been cited as evidence that testosterone has anabolic effects. However, the effects of testosterone on body composition and muscle size have not been rigorously studied. The objective of this study was to determine the effects of replacement doses of testosterone on fat-free mass and muscle size in healthy hypogonadal men in the setting of controlled nutritional intake and exercise level. Seven hypogonadal men, 19-47 yr of age, after at least a 12-week washout from previous androgen therapy, were treated for 10 weeks with testosterone enanthate (100 mg/week) by im injections. Body weight, fat-free mass measured by underwater weighing and deuterated water dilution, and muscle size measured by magnetic resonance imaging were assessed before and after treatment. Energy and protein intake were standardized at 35 Cal/kg.day and 1.5 g/kg.day, respectively. Body weight increased significantly from 79.2 +/- 5.6 to 83.7 +/- 5.7 kg after 10 weeks of testosterone replacement therapy (weight gain, 4.5 +/- 0.6 kg; P = 0.0064). Fat-free mass, measured by underwater weighing, increased from 56.0 +/- 2.5 to 60.9 +/- 2.2 kg (change, +5.0 +/- 0.7 kg; P = 0.0004), but percent fat did not significantly change. Similar increases in fat-free mass were observed with the deuterated water method. The cross-sectional area of the triceps arm muscle increased from 2421 +/- 317 to 2721 +/- 239 mm2 (P = 0.045), and that of the quadriceps leg muscle increased from 7173 +/- 464 to 7720 +/- 454 mm2 (P = 0.0427), measured by magnetic resonance imaging. Muscle strength, assessed by one repetition maximum of weight-lifting exercises increased significantly after testosterone treatment. L-[1-13C]Leucine turnover, leucine oxidation, and nonoxidative disappearance of leucine did not significantly change after 10 weeks of treatment. There was no significant change in hemoglobin, hematocrit, creatinine, and transaminase levels. Replacement doses of testosterone increase fat-free mass and muscle size and strength in hypogonadal men. Whether androgen replacement in wasting states characterized by low testosterone levels will have similar anabolic effects remains to be studied.

We have previously established Adriamycin-resistant HOB1 cell lines showing the multidrug resistance (MDR) phenotype. For further study, we analyzed the free-radical scavengers glutathione S-transferase (GST) and glutathione peroxidase (GPX) by enzyme assays and Northern blots. Three cell lines, HOB1/ADR0.1, HOB1/ADR1.0, and HOB1/ADR5.0, represented HOB1 cells resistant to 0.1, 1.0, and 5.0 microM Adriamycin, respectively. The mdr1 transcript was overexpressed in HOB1/ADR0.1 cells, and the amount of its expression reached a maximum between HOB1/ADR1.0 and HOB1/ADR5.0 cell lines. The increases in GST activity and GST-pi expression were observed only in high-level-resistant cell line (HOB1/ADR1.0 and HOB1/ADR5.0), which also showed increased GPX activity and expression. For investigation of the cytotoxic effect of Adriamycin on HOB1 cells prior to the mdr1 overexpression, an appropriate number of parental HOB1 cells were treated with 0.1 microM Adriamycin for 7 days, and the viable cells (HOB1/ADR) were isolated and subjected to analyses for mdr1, GST-pi, and GPX expression and for GST and GPX activity. In comparison with HOB1/ADR0.1 cells, HOB1/ADR cells did not show mdr1 overexpression but had significant increases in the activity and expression of GST and GPX. The current study suggests that in the early phase of Adriamycin treatment, GST and GPX are more important than P-glycoprotein for the development in HOB1 cells of resistance against Adriamycin.

We have shown that unesterified, unsaturated long-chain fatty acids inhibit angiotensin II (AII) binding to receptors in adrenal glomerulosa cells. In this report, we show that oleic and arachidonic acids are specific inhibitors of the AT1 subtype of angiotensin receptor, and exert no effect on receptors of the AT2 subtype. By contrast, decanoic acid is a weak inhibitor of the AT2 subtype only. Our previous work on a post-receptor locus of inhibition by fatty acids of aldosterone biosynthesis showed that the 18-oxidase step is uniquely sensitive. In brief, the first and last steps involved in angiotensin-stimulated aldosterone secretion are particularly sensitive to inhibition by fatty acids. These results suggest a specific role for unesterified fatty acids in regulation of salt and water metabolism.

Objective Clonidine is an α 2 -adrenoceptor agonist which, by coupling with G-protein, has been proposed as an alternative treatment for refractory ascites of patients with cirrhosis for several years. Genetic polymorphisms of β-adrenoceptor and angiotensin II type 1 receptor blockers have been reported to affect drug response in patients with cirrhosis. This study evaluated the clonidine–diuretic response rate, favourable predictors and genetic components of the clonidine–diuretic response in patients with cirrhosis with refractory ascites. Methods 270 patients with cirrhosis with refractory ascites were randomised equally into two treatment groups to receive diuretics alone or the clonidine–diuretics association. The primary end point was clonidine–diuretic response rate. Secondary end points were mean daily dose of diuretics, times of paracentesis, ascites-related readmission and 1-year survival rate. Results Good clonidine responders had better natriuresis and diuresis as well as a significant decrease in abdominal circumference, plasma renin, aldosterone and norepinephrine levels. The overall clonidine–diuretics response rate was 55–60%. In patients with cirrhosis, the prevalence of ARDA 2 C WD/DD and GNB3 CT/TT genotypes was 71% and 77%, respectively. Among the responders, 71% of patients with cirrhosis had the ARDA 2 C WD/DD genotype and 67% has the GNB3 CT/TT genotype. Besides higher baseline norepinephrine levels, the presence of both ARDA 2 C WD/DD and GNB3 CT/TT genotypes showed a positive predictive value of 82% and a negative predictive value of 79% for good clonidine response. Conclusions These results suggest that neurohormonal and genetic testing may be used as predictive factors for the additive effects of clonidine on the diuresis and natriuresis effects of diuretics in patients with cirrhosis with refractory ascites.

The rheological properties of mung bean starch pastes were characterised using a co-axial rotational viscometer. The flow curves of pastes were typical of a viscoplastic shear thinning behaviour, no yield value was evident and the pastes showed unusual resistance to high shear forces. The rheological properties of these pastes were thought to result from the combined influence of intact swollen granules and an extensive extragranular network of exuded amylose. Fliesverhalten von Mungbohnenstarke-Pasten. Unter Verwendung eines koaxialen Rotationsviskosimeters wurden die rheologschen Eigenschaften von Mungbohnenstarke-Pasten charakterisiert. Die Flieskurven der Pasten waren typisch fur ein viskoplastisches Scher-Verdunnungsverhalten, kein Ergiebigkeitswert trat auf, und die Pasten zeigten ungewohnlichen Widerstand gegenuber hohen Scherkraften. Die rheologischen Eigenschaften der Pasten wurden auf den kombinierten Einflus von intakten gequollenen Kornern und ein ausgedehntes Netzwerk von exsudierter Amylose auserhalb der Korner zuruckgefuhrt.

Conventionally, wafers are passivated by thermal oxidation at temperatures exceeding 900 °C for about an hour prior to effective minority carrier recombination lifetime measurement. This article discusses a method where a reduced duration and low-temperature (650 °C) oxidation followed by ultraviolet radiation was found to be efficacious in passivating silicon wafers for photoconductive decay measurements. The effective minority carrier recombination lifetimes of wafers deliberately contaminated with iron, measured by the conventional and the present methods were well correlated.

An Atomic Force Microscopy system for nanostructure patterning through local anodic oxidation is designed and constructed. We introduce here a novel method of patterning using motorized high precision XY stages controlled by software to provide precise pattern movements while the tip remains stationery, as opposed to conventional tip movements. A microscope with solid state camera imaging system is integrated to obtain real time images of the cantilever to ‘mark’ the precise location of patterns. We have successfully demonstrated the patterning of nanoscale oxide structures on silicon sample using this system.

Hepatic glucose production (HGP) and glucose carbon recycling are traditionally estimated by the combined use of hydrogen and carbon-labeled glucose tracers. A single-isotope method such as that of Reichard et al. for the determination of HGP and glucose carbon recycling requires the determination of activities in different glucose carbons by chemical degradation. Since the 13C content in the glucose carbon skeleton can be determined from mass fragmentography, the use of 13C-labeled glucose and mass fragmentography can provide a single-isotope method for the quantification of the recycled carbons. Correction for the recycling makes it possible to determine the true HGP. In this study, (1-13C1)glucose and mass fragmentography were used for the determination of HGP and glucose carbon recycling in six colon cancer patients. Molar enrichment of the molecular ion (m/z 328 cluster of glucose aldonitrile pentaacetate) was used to determine 'uncorrected' HGP, which was 1.93 +/- 0.11 mg kg-1 min-1 (mean +/- s.e.m.). The difference in molar enrichment of the molecular ion C1-C6 (m/z 328) and the ion corresponding to C1-C4 fragment (m/z 242) was used to determine the contribution of recycled label carbon. After this correction, the 'corrected' HGP was 2.04 +/- 0.12 mg kg-1 min-1, which is not significantly different from the 'true' HGP rate of 2.05 +/- 0.15 mg kg-1 min-1 determined by using (6-3H)glucose. HGP determined from the enrichment of the molecular ion C1-C6 underestimates true HGP, as expected. The corrected HGPs correlate well with those from 6-3H method (r = 0.86, y = 1.06x - 0.12; p less than 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)

On-line gas chromatography/combustion/isotope ratio mass spectrometry (GC/C/IRMS) was evaluated for use in stable isotope studies of human cholesterol metabolism. Calibration curves were constructed by analyzing underivatized and TMS-cholesterol over a range of 13C abundances from natural abundance to 0.05 mol of [3,4-13C]cholesterol per mole of unlabeled cholesterol (delta 13C -24 to 27/1000). The calibration curves were highly linear (r2 = 0.99) with slopes of 0.98 and 0.88 for underivatized and TMS-cholesterol, respectively. Higher precision of 13C/12C ratio determination was obtained using TMS-cholesterol, with a detection limit (2 SD) of 0.3/1000 or 0.004 mol% of [3,4-13C]cholesterol. By comparison standard GC/MS had a detection limit of 0.06 mol% for [3,4-13C]cholesterol. A 57-day study of cholesterol elimination was conducted in one human subject with oral administration of 50 mg of [3,4-13C]cholesterol. Peak enrichment was 9/1000 above baseline (40 times the detection limit) and could be followed for 40-50 days. The results indicate that GC/C/IRMS provides 15-fold lower detection limits for [3,4-13C]cholesterol than GC/MS and is useful for human studies of cholesterol metabolism.

This paper is written in three parts as following. (1) The maximum conductivity issue of the newly processed polyacetylene is reexamined. (2) The organic fer-romagnetism of the pyrolyzed polyacrylonitrile (Pyro-PAN) has been investigated by the electrical conductivity and thermoelectric power (TEP) as well as the magnetic susceptibility with hysteresis measurements using a SQUID magnetometer. (3) The electrical properties of the alkali metal intercalated bulk C60 has been studied in the normal state.

We have focused recent efforts on developing an understanding of how to optimise the electrical, spectroscopic, electrochemical and physical properties of poly(3,4-alkylenedioxythiophene) (PXDOT) and poly(3,4-alkylenedioxypyrrole) (PXDOP) based conjugated polymers. Here we present the results of the temperature dependence of the dc and microwave conductivity, as well as magnetic susceptibility and reflectance data, for electrochemically synthesized, free standing, PXDOT and PXDOP films doped with different organic anions. The polymers have properties that are characteristic of disordered materials near the insulator-metal transition (IMT). We also investigate the possibility of applying these polymers as the active layer in visible and IR light emissivity control devices.

We present the charge transport and magnetic properties of polyaniline doped with 2-acrylamido-2-methyl sulfonated propanoic acid (PAN-AMSPA) including temperature dependent dc conductivity σ DC (t), thermoelectric power S(T), and electroparamagnetic resonance (EPR). The temperature dependent reduced activation energy W(T) plot from σ DC (T) with σ(300K) ~ 140 S/cm and a(10K)/σ(300K) ~ 0.9 shows that PAN-AMSPA is in the metallic regime of the insulator-metal transition. The analysis of EPR (9.5GHz) Dysonian lineshape results in substantially larger σ MW than σ DC . Results are discussed in terms of inhomogenous disordered materials. U-shaped S(T) with S(300K) ~ + 2.5 ± 0.5 μV/K can be explained in terms of an effective medium model in accord with the inhomogeneous disorder present. For the stretched samples, the temperature dependences of σ DC (t) are stronger than that of unstretched sample with the weak temperature dependent anisotropy, even though the parallel direction room temperature values are higher than that of unstretched sample. This is consistent with expected effects from the inhomogeneous disorder.

Grown-in crystal-originated particles (COPs) on the surface of silicon nitride-doped Czochralski (CZ)-grown silicon wafers were characterized using atomic force microscopy and scanning electron microscopy. These nanometer-scale COPs are categorized into kite-shaped, parallelepiped- plate and needle-shaped COPs, respectively, with unique features distinctively different from the octahedral voids commonly found in conventional CZ-grown silicon wafers. Based on the experimental data obtained, it is postulated that nitrogen dopants in the silicon crystals could influence the formation of these COPs with different morphologies and sizes. This may be supported by a simple analysis of the mapping distribution of COPs on the nitride-doped CZ-grown silicon wafer, which reveals that the densities of the smaller-size parallelepiped- plate and needle-shaped COPs are negligible at the center of the silicon wafer but increase to a significant proportion comparable to that of the kite-shaped COPs at the outer edges of the silicon wafer along the radial directions. These observations are thought to correlate well with the presence of nitrogen dopants and the radial concentrations of the excess free vacancy. (c) 2006 The Electrochemical Society.

We report the results of temperature (T) dependence of dc conductivity (σdc) for polyaniline (PAN) pellet samples with various dopants (BSA, NSA, ISA, and CSA) in organic solvents (m-cresol, CHCl3, BeOH) and the mixtures of PAN-DBSA (CHCl3) and PANBSA (m-cresol). σdc(T) of PAN pellets varies with dopants in the same solvent. However using different solvent, σdc(T) with the same dopant dramatically changes, which indicates that transport properties, can be controlled by both dopants and solvents. The mixture of PAN-DBSA (CHCl3) and PAN-BSA (m-cresol) induces the increase of σdc and the variation from the insulating regime to the critical one.

We report the results of temperature (7) dependence of dc conductivity (σdc), microwave dielectric constant, and EPR experiment for soluble polypyrrole (PPY) samples with different dopants (DBSA and NSA) prepared using various organic solvents (NMP, m-cresol, CHCl3, and DMSO). The three dimensional variable range hopping (VRH) model provides the best fit to the data, while the slope of σdc(T) varies with dopants and solvents used. σdc at room temperature is ~ 0.2 0.01 S/cm and the localization length is estimated as 5 A, which indicates the relatively strong localization of charge for these materials. We discuss the relation between the polarity of solvent and σdc(T). From EPR experiment, the density of states of the systems is estimated.

We present a charge transport study of a newly prepared fully sulfonated polyaniline IN-SPAN) with the sulfur-to-nitrogen (S/N) ratio ∼ 1.0. The temperature dependent dc conductivity is fit by the quasi-1D variable range hopping model: σ dc (T) = σ 0 exp [-(T 0 /T) γ ], where γ ∼ 0.5 with σ RT ∼ 0.02 S/cm and To = 1.5 x 10 4 K. Thermoelectric power measurement shows a weak temperature dependence, which also is consistent with the quasi-1D variable range hopping model. The microwave conductivity follows a typical temperature dependence for materials in which the hopping conduction mechanism is dominant. The density of states at the Fermi level N( eF ) is calculated as ∼ 0.27 states/eV-2 rings for each sign of spin based on EPR measurements. The density of Curie spin is 0.0033 spins/2-rings. The origin of the lower room temperature conductivity, smaller density of states and fewer Curie spin than those of two previously reported SPANs with S/N ratio - 0.5 and 0.75 is suggested to be the larger twist of the phenyl rings relative to one another and increased interchain separation both due to the introduction of methoxy side groups and the higher density of SO 3 - groups. This morphology favors bipolaron formation.

Crystal-originated particle (COP) side-wall angles and rates of change in width were measured after treatment in an SC-1 solution by atomic force microscopy (AFM) to determine the shape, size and type of the particles on a polished (100) Si wafer surface. The etched silicon tip's maximum measurable slope angles were used to determine whether a COP originated from either the upper or the lower portion of an octahedral void. If the COP side-wall angle is equal to the maximum measurable slope angle of around 72°, the COP originated from the upper portion of the void. The lower portion of an octahedral void corresponds to a side-wall angle of 55°. This was confirmed through the study of COP width changes in NH4OH:H2O2:H2O (SC-1) solution. The COP width depends on the rates of change in width and the shape of its void. The rates of change of width of the COP which originated from the lower portion of the void was found to be 0.8 nm/min whereas that of the COP which originated from the upper portion of the void was 2.5 nm/min. It is also shown that a perceived single-type COP could very well be the upper part of a twin-type COP, which reveals its form of a much larger geometry only after the wafers are dipped repeatedly in the SC-1 solution.