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Treatment of liver fibrosis is very limited as there is currently no effective anti-fibrotic therapy. Spirulina platensis (SP) is a blue-green alga that is widely supplemented in healthy foods. The objective of this study was to determine whether SP supplementation can prevent obesity-induced liver fibrosis in vivo. Male C57BL/6J mice were randomly assigned to a low-fat or a high-fat (HF)/high-sucrose/high-cholesterol diet or an HF diet supplemented with 2·5 % SP (w/w) (HF/SP) for 16 or 20 weeks. There were no significant differences in body weight, activity, energy expenditure, serum lipids or glucose tolerance between mice on HF and HF/SP diets. However, plasma alanine aminotransferase level was significantly reduced by SP at 16 weeks. Expression of fibrotic markers and trichrome stains showed no differences between HF and HF/SP. Splenocytes isolated from HF/SP fed mice had lower inflammatory gene expression and cytokine secretion compared with splenocytes from HF-fed mice. SP supplementation did not attenuate HF-induced liver fibrosis. However, the expression and secretion of inflammatory genes in splenocytes were significantly reduced by SP supplementation, demonstrating the anti-inflammatory effects of SP in vivo. Although SP did not show appreciable effect on the prevention of liver fibrosis in this mouse model, it may be beneficial for other inflammatory conditions.
This paper presents the fabrication technology and initial characterization of electrolyte-gated field effect transistor (FET) arrays based on CVD grown graphene on copper. We show that the graphene FET (GFET), when immersed in electrolytes, exhibit a transconductance around 5 mS/mm. From preliminary pH sensing experiments, a pH sensitivity of 24 mV/pH has been demonstrated.
This is a copy of the slides presented at the meeting but not formally
written up for the volume.
Recent advancements in various industries have necessitated the
development of new engineering materials exhibiting superior properties
of different character. For example, composite electroplating renders
excellent corrosion- and wear-resistant materials with good lubrication
behavior and chemical stability. Nanometer-sized diamond particles are
expected to be good dispersion materials in electro-less composite
plating. However, the processing conditions and characteristics of
metal/diamond composites are not well understood so far. In this
investigation, we developed new processes for co-deposition of
Ni-P/diamond composite films on steel plates using the commercial
electrolyte composed of nickel sulfate and sodium hypophosphite. No
additives were applied in this process as in the conventional methods for
the efficient dispersion of diamond particles. The diamond particles of a
few hundred nanometer size were dispersed in an ultrasonic bath of
de-ionized water. The zeta potential of the diamond solution was measured
prior to the incorporation into the electrolyte. The morphology of the
prepared films was characterized by FESEM. Based on the FESEM images, the
size distribution of the diamond particles was determined using an image
analyzer program. The micro-hardness, the coefficient of friction, and
the corrosion potential were measured by Vickers hardness tester,
tribometer and potentiometer, respectively. The present experimental
results revealed remarkable differences in the values of the
micro-hardness, the coefficient of friction, and the corrosion potential,
compared to those of conventional diamond-free electro-less Ni-P plates.
Process conditions were optimized in terms of the concentration of
diamond particles, ultrasonic dispersion time, and pH of the electrolyte.
As the concentration of diamond particles increased from 0.5to 3g/l, the
zeta potential was decreasing with more particles aggregated. The higher
the diamond concentration, the higher the volume fraction of diamond
particles co-deposited in the nickel matrix. In turn, the coefficient of
friction and corrosion potential increasd with the increasing diamond
concentration. The particle size distribution was the most uniform in the
samples prepared at the concentration of 1.0g/l. The best mechanical
properties were obtained when the dispersion time was 30min. and the pH
RF MEMS(Micro-Electro-Mechanical-System) switch technology is one of powerful solution for future RF systems. This technology provides low insertion loss, High linearity and broad bandwidth. Wide driving membrane used MEMS switch can reduce driving voltage but it is easy to bend because of the stress gradient. In order to solve this problem we fabricated Au cantilever in various sputtering condition and various substrate materials. As a result of this experiment, we fabricated cantilever which was bent within 1 um, with 2 um thickness and 340 um length. We applied this condition to RF MEMS switch and we fabricated switch membrane within 1 um bend, under 10MPa stress gradient.
High performance poly-Si thin film transistors were fabricated by using a new crystallization method, Metal-Induced Lateral Crystallization (MILC). The process temperature was kept below 500°C throughout the fabrication. After the gate definition, thin nickel films were deposited on top of the TFT's without an additional mask, and with a one-step annealing at 500°C, the activation of the dopants in source/drain/gate a-Si films was achieved simultaneously with the crystallization of the a-Si films in the channel area. Even without a post-hydrogenation passivation, mobilities of the MILC TFT's were measured to be as high as 120cm2/Vs and 90cm2/Vs for n-channel and p-channel, respectively. These values are much higher than those of the poly-Si TFT's fabricated by conventional solid-phase crystallization at around 6001C.
A novel processing sequence for the formation of gated diamond field emitter arrays (triode system) is proposed and the feasibility is tested by investigating the field emission property. The processing scheme is based on the selective deposition of diamond using the well established nucleation enhanced process on silicon substrate, so called bias enhanced nucleation (BEN). Selective deposition of diamond using the same process was also demonstrated on titanium nitride (TIN) electrode layer. Our preliminary results show that the diamond field emitter is turned on at around 97 V/μm with the current level of about several μA.
The film properties of WNxCy films deposited by atomic layer deposition (ALD) using WF6, NH3, and triethylboron source gases were characterized as diffusion barrier for Cu metallization. It is noted that the as-deposited film shows an extremely low resistivity of about 350 μΔ-cm with a film density of 15.37 g/cm3. The film composition measured from Rutherford backscattering spectrometry shows W, C, and N of approximately 48, 32, and 20 at.%, respectively. Transmission electron microscopy analyses show that the as-deposited film is composed of face-centered-cubic phase with a lattice parameter similar to both β-WC1-x and β-W2N with an equiaxed microstructure. The barrier property of this ALD-WNxCy film at a nominal thickness of 12 nm deposited between Cu and Si fails only after annealing at 700°C for 30 minutes while the sputter-deposited Ta (12 nm) and ALD-TiN (20 nm) fail at 650 and 600°C, respectively. It is thought that the superior diffusion barrier performance of ALD-WNxCyfilm is the consequence of both nanocrystalline equiaxed grain structure and the formation of high density film.
Conventional Ge2Sb2Te5 (GST) was modified by adding up a small amount of SiOx, using co-sputtering technique from multiple targets. The SiOx content was gradually increased by increasing the power applied to SiOx target, up to 8 volume percent. The sheet resistance of SiOx-containing GST exponentially increased, when the room-temperature-deposited samples were annealed at 300 °C. Transmission electron microscopy images revealed that no SiOx particulates were formed, which was confirmed by Gattan image filtering. It was indicated by x-ray diffraction patterns that the grain size of SiOx-containing GST is smaller than normal GST with lattice locally distorted at its crystalline state, suggesting that molecular SiOx is homogeneously distributed throughout the GST matrix. We observed that the crystallization temperature of SiOx-containing GST is gradually elevated by increasing the SiOx content, while the melting point decreased. These observations led to the reset current reduction, which is a critical requirement for the high density PRAM.
The hydrophobicity of poly Si is reported to introduce different polishing behavior with careful control of post CMP cleaning process. The purpose of this study was to investigate the effect of poly Si wettability on its CMP behavior. The adhesion force of polymeric particle on the poly Si wafer surfaces was measured in the KOH solution (pH 11) as a function of solution A concentration. Adhesion force decreased and saturated as a function of concentration of solution A. The change of surface wettability affects not only the polishing rates but also the level of contamination on wafer because the interactions between particles and substrates are dependent on the wettability of the surface. Also, hydrophobic poly Si surfaces attracted much more pad particles with water marks than hydrophilic
Polyimides thin films, which are the most commonly used group of sensing materials for capacitive humidity sensors, were cured locally using MEMS microhotplates. The polyimide locally cured at temperature over 350 °C for 1 hour was fully cured. There were no significant differences in the polyimide thin films between cured in convection ovens and locally cured on microhotplate. The locally cured polyimide humidity sensor showed a linearity of 0.9995, a sensitivity of 0.766pF/%RH, a hysteresis of 0.6%RH, and a time response of 3 s. These results show the possibility of locally-cured polyimide films as high speed, high-sensitivity humidity sensors.
Sol-gel derived photosensitive inorganic-organic hybrid materials (Photo-HYBRIMER) containing a large quantity of photoactive molecules exhibit the large changes in both refractive index (over 10-2) and volume (over 30%) on UV exposure. The materials could be used for direct fabrication of micro-optical devices using holographic interference. With the change of the beam number for holographic interference (1-beam, 2-beam, 3-beam and 4-beam interference), various typed micro-optical devices (Fresnel-type lens, 1D- and 2D-typed diffraction gratings) could be easily fabricated. Importantly, the fabricated micro-optical devices exhibited the very homogeneous surface structures and good optical performance.
We investigate boron transient enhanced diffusion (TED) and series resistance in SiGe/Si heterojunction channel pMOSFET. The stress gradient at the SiGe/Si interface near the gate edge in high Ge concentrations are found to determine boron TED as well as extension junction shape, which has a significant impact on the parasitic LDD and source/drain (S/D) series resistance. In addition, high Ge concentrations in the epitaxial SiGe layer on top of Si substrate result in a high sheet resistance during a 1000°C/5s rapid thermal processing (RTP), which is mainly due to alloy scattering and interface roughness scattering.
Cocoa polyphenols have antioxidant and anti-inflammatory effects. TNF-α is a pro-inflammatory cytokine that has a vital role in the pathogenesis of inflammatory diseases such as cancer and psoriasis. Vascular endothelial growth factor (VEGF) expression is associated with tumorigenesis, CVD, rheumatoid arthritis and psoriasis. We tested whether cocoa polyphenol extract (CPE) inhibited TNF-α-induced VEGF expression in promotion-sensitive JB6 mouse epidermal cells. CPE significantly inhibited TNF-α-induced up-regulation of VEGF via reducing TNF-α-induced activation of the nuclear transcription factors activator protein-1 (AP-1) and NF-κB, which are key regulators of VEGF expression. CPE also inhibited TNF-α-induced phosphorylation of protein kinase B (Akt) and extracellular signal-regulated kinase. CPE blocked activation of their downstream kinases, p70 kDa ribosomal protein S6 kinase and p90 kDa ribosomal protein S6 kinase. CPE suppressed phosphoinositide 3-kinase (PI3K) activity via binding PI3K directly. CPE did not affect TNF-α-induced phosphorylation of mitogen-activated protein kinase kinase-1 (MEK1) but suppressed TNF-α-induced MEK1 activity. Collectively, these results indicate that CPE reduced TNF-α-induced up-regulation of VEGF by directly inhibiting PI3K and MEK1 activities, which may contribute to its chemopreventive potential.
We evaluated the effects of the two main kiwifruit cultivars (gold kiwifruit (GOK) and green kiwifruit (GRK)) and their active phenolic compound, quercetin, on H2O2-induced inhibition of gap-junction intercellular communication (GJIC) in WB-F344 rat liver epithelial cells. We found that both GOK and GRK protect WB-F344 cells from H2O2-induced inhibition of GJIC. The extracellular signal-regulated protein kinase 1/2 (ERK1/2)–connexin 43 (Cx43) signalling pathway is crucial for the regulation of GJIC, and both GOK and GRK blocked the H2O2-induced phosphorylation of Cx43 and ERK1/2 in WB-F344 cells. Quercetin alone attenuated the H2O2-mediated ERK1/2–Cx43 signalling pathway and consequently reversed H2O2-mediated inhibition of GJIC in WB-F344 cells. A free radical-scavenging assay using 1,1-diphenyl-2-picrylhydrazyl showed that the scavenging activity of quercetin was higher than that of a synthetic antioxidant, butylated hydroxytoluene, per mol, suggesting that the chemopreventive effect of quercetin on H2O2-mediated inhibition of ERK1/2–Cx43 signalling and GJIC may be mediated through its free radical-scavenging activity. Since the carcinogenicity of reactive oxygen species such as H2O2 is attributable to the inhibition of GJIC, GOK, GRK and quercetin may have chemopreventive potential by preventing the inhibition of GJIC.
The sap of Acer mono has been called ‘bone-benefit-water’ in Korea because of its mineral and sugar content. In particular, the calcium concentration of the sap of A. mono is 37·5 times higher than commercial spring water. In the current study, we examined whether A. mono sap could improve or prevent osteoporosis-like symptoms in a mouse model. Male mice (3 weeks old) were fed a low-calcium diet supplemented with 25, 50 or 100 % A. mono sap, commercial spring water or a high calcium-containing solution as a beverage for 7 weeks. There were no differences in weekly weight gain and food intake among all the groups. Mice that were given a low-calcium diet supplemented with commercial spring water developed osteoporosis-like symptoms. To assess the effect of sap on osteoporosis-like symptoms, we examined serum calcium concentration, and femur density and length, and carried out a histological examination. Serum calcium levels were significantly lower in mice that received a low-calcium diet supplemented with commercial spring water (the negative control group), and in the 25 % sap group compared to mice fed a normal diet, but were normal in the 50 and 100 % sap and high-calcium solution groups. Femur density and length were significantly reduced in the negative control and 25 % sap groups. These results indicate that a 50 % sap solution can mitigate osteoporosis-like symptoms induced by a low-calcium diet. We also examined the regulation of expression of calcium-processing genes in the duodenum and kidney. Duodenal TRPV6 and renal calbindin-D9k were up-regulated dose-dependently by sap, and the levels of these factors were higher than those attained in the spring water-treated control. The results demonstrate that the sap of A. mono ameliorates the low bone density induced by a low-calcium diet, most likely by increasing calcium ion absorption.
To evaluate the clinical features of ciprofloxacin-resistant Enterobacter bacteremia and to examine the risk factors for ciprofloxacin resistance in Enterobacter species isolates causing bacteremia.
A case-control study.
A 1,500-bed, tertiary-care university hospital and referral center.
All patients older than 16 years with Enterobacter species isolated from blood were enrolled. The medical records of 183 patients with clinically significant Enterobacter bacteremia from January 1998 to December 2002 were identified. We compared patients with bacteremia caused by ciprofloxacin-susceptible isolates with patients with bacteremia caused by ciprofloxacin-resistant isolates.
Twenty-three (12.6%) of the patients had bacteremia caused by isolates resistant to ciprofloxacin. There were no significant differences in age, gender, underlying diseases, primary site of infection, or Acute Physiology and Chronic Health Evaluation II score between the ciprofloxacin-resistant and the ciprofloxacin-susceptible groups. Broad-spectrum cephalosporin resistance, defined as resistance to cefotaxime or ceftazidime in vitro, was detected in 21 (91.3%) of 23 ciprofloxacin-resistant isolates compared with 65 (40.6%) of 160 ciprofloxacin-susceptible isolates (P < .001). Multivariate analysis revealed that independent risk factors for ciprofloxacin resistance were the prior receipt of fluoroquinolones (P < .001) and broad-spectrum cephalosporin resistance (P < .001).
In Enterobacter species isolates causing bacteremia, ciprofloxacin resistance was closely associated with the prior receipt of fluoroquinolones and broad-spectrum cephalosporin resistance. The close relationship between ciprofloxacin resistance and broad-spectrum cephalosporin resistance is particularly troublesome because it severely restricts the therapeutic options for Enterobacter species infection.
This paper describes the growth kinetics of an interfacial MgO layer as well as those of an MgB2 layer during ex situ annealing of the evaporated amorphous boron (a-B) film under Mg vapor overpressure. A thin MgO layer is formed at the interface between a-B and Al2O3 substrate before the formation of crystalline MgB2 layer and the interfacial layer is epitaxially related with Al2O3 substrate (MgO (111) // Al2O3 (0001)). The interfacial MgO layer continues to grow during the annealing, and its apparent growth rate is about 0.1 nm/min. The analysis of MgB2 layer growth kinetics using cross-sectional transmission electron microscopy reveals that there exist two distinct growth fronts at both sides of an MgB2 layer. The growth kinetics of the lower MgB2 layer obeys the parabolic rate law during the entire annealing time. The growth of the upper MgB2 layer is controlled by the surface reaction between out-diffused boron and Mg vapor up to 10 min, resulting in a rough surface morphology of MgB2 layer. By considering the mass balance of Mg and boron during ex situ annealing, we obtained the diffusivities of Mg and boron in MgB2 layer which were in the same order range of approximately 10−12 cm2/s.
To evaluate risk factors and treatment outcomes of bloodstream infections caused by extended-spectrum beta-lactamase-producing Klebsiella pneumoniae (ESBL-KP).
Retrospective case-control study. Stored blood isolates of K. pneumoniae were tested for ESBL production by NCCLS guidelines, double-disk synergy test, or both.
A 1,500-bed, tertiary-care university hospital and referral center.
Sixty case-patients with bacteremia due to ESBL-KP were compared with 60 matched control-patients with non-ESBL-KP.
There were no significant differences in age, gender, APACHE II score, or underlying diseases between the groups. Independent risk factors for infections caused by ESBL-KP were urinary catheterization, invasive procedure within the previous 72 hours, and an increasing number of antibiotics administered within the previous 30 days. Complete response rate, evaluated 72 hours after initial antimicrobial therapy, was higher among control-patients (13.3% vs 36.7%; P = .003). Treatment failure rate was higher among case-patients (35.0% vs 15%; P = .011). Overall 30-day mortality rate was 30% for case-patients and 28.3% for control-patients (P = .841). Case-patients who received imipenem or ciprofloxacin as a definitive antibiotic had 10.5% mortality. The mortality rate for initially ineffective therapy was no higher than that for initially effective therapy (9.1% vs 11.1%; P = 1.000), but statistical power was low for evaluating mortality in the absence of septic shock.
For K. pneumoniae bacteremia, patients with ESBL-KP had a higher initial treatment failure rate but did not have higher mortality if antimicrobial therapy was appropriately adjusted in this study with limited statistical power.
The reaction sequence and microstructure evolution of a crystalline MgB2 layer were examined during ex situ annealing of evaporated amorphous boron (a-B) with Mg vapor. Mg was found to migrate rapidly into the a-B layer in the initial stage of reaction with a uniform concentration of about 12 at.%. A thin layer of crystalline MgO was observed at the interface between a-B and the Al2O3 substrate. It was identified that an MgB2 layer started to form at the surface by the nucleation and growth process in polycrystalline form. It appears that there exists two distinct growth fronts in the MgB2 layer: one lying at the surface and the other lying at the interface between the MgB2 layer and the a-B. The microstructural evolution of this layer showed significant differences depending on the location of these two growth fronts.