Hydrogen-Doping-Enabled Boosting of the Carrier Mobility and Stability in Amorphous IGZTO Transistors.

This study investigated the effect of hydrogen (H) on the performance of amorphous In-Ga-Zn-Sn oxide (a-In0.29Ga0.35Zn0.11Sn0.25O) thin-film transistors (TFTs). Ample H in plasma-enhanced atomic layer deposition (PEALD)-derived SiO2 can diffuse into the underlying a-IGZTO film during the postdeposition annealing (PDA) process, which affects the electrical properties of the resulting TFTs due to its donor behavior in the a-IGZTO. The a-In0.29Ga0.35Zn0.11Sn0.25O TFTs at the PDA temperature of 400 °C exhibited a remarkably higher field-effect mobility (µFE) of 85.9 cm2/Vs, a subthreshold gate swing (SS) of 0.33 V/decade, a threshold voltage (VTH) of -0.49 V, and an ION/OFF ratio of ∼108; these values are superior compared to those of unpassivated a-In0.29Ga0.35Zn0.11Sn0.25O TFTs (µFE = 23.3 cm2/Vs, SS = 0.36 V/decade, and VTH = -3.33 V). In addition, the passivated a-In0.29Ga0.35Zn0.11Sn0.25O TFTs had good stability against the external gate bias duration. This performance change can be attributed to the substitutional H doping into oxygen sites (HO) leading to a boost in ne and µFE. In contrast, the beneficial HO effect was barely observed for amorphous indium gallium zinc oxide (a-IGZO) TFTs, suggesting that the hydrogen-doping-enabled boosting of a-IGZTO TFTs is strongly related to the existence of Sn cations. Electronic calculations of VO and HO using density functional theory (DFT) were performed to explain this disparity. The introduction of SnO2 in a-IGZO is predicted to cause a conversion from shallow VO to deep VO due to the lower formation energy of deep VO, which is effectively created around Sn cations. The formation of HO by H doping in the IGZTO facilitates the efficient connection of atomic states forming the conduction band more smoothly. This reduces the effective mass and enhances the carrier mobility.

Boosting carrier mobility and stability in indium-zinc-tin oxide thin-film transistors through controlled crystallization.

We investigated the effect of film thickness (geometrical confinement) on the structural evolution of sputtered indium-zinc-tin oxide (IZTO) films as high mobility n-channel semiconducting layers during post-treatment at different annealing temperatures ranging from 350 to 700 °C. Different thicknesses result in IZTO films containing versatile phases, such as amorphous, low-, and high-crystalline structures even after annealing at 700 °C. A 19-nm-thick IZTO film clearly showed a phase transformation from initially amorphous to polycrystalline bixbyite structures, while the ultra-thin film (5 nm) still maintained an amorphous phase. Transistors including amorphous and low crystalline IZTO films fabricated at 350 and 700 °C show reasonable carrier mobility (µFE) and on/off current ratio (ION/OFF) values of 22.4-35.9 cm2 V-1 s-1 and 1.0-4.0 × 108, respectively. However, their device instabilities against positive/negative gate bias stresses (PBS/NBS) are unacceptable, originating from unsaturated bonding and disordered sites in the metal oxide films. In contrast, the 19-nm-thick annealed IZTO films included highly-crystalline, 2D spherulitic crystallites and fewer grain boundaries. These films show the highest µFE value of 39.2 cm2 V-1 s-1 in the transistor as well as an excellent ION/OFF value of 9.7 × 108. Simultaneously, the PBS/NBS stability of the resulting transistor is significantly improved under the same stress condition. This promising superior performance is attributed to the crystallization-induced lattice ordering, as determined by highly-crystalline structures and the associated formation of discrete donor levels (~ 0.31 eV) below the conduction band edge.

Scopoletin from Cirsium setidens Increases Melanin Synthesis via CREB Phosphorylation in B16F10 Cells.

In this study, we isolated scopoletin from Cirsium setidens Nakai (Compositae) and tested its effects on melanogenesis. Scopoletin was not toxic to cells at concentrations less than 50 µM and increased melanin synthesis in a dose-dependent manner. As melanin synthesis increased, scopoletin stimulated the total tyrosinase activity, the rate-limiting enzyme of melanogenesis. In a cell-free system, however, scopoletin did not increase tyrosinase activity, indicating that scopoletin is not a direct activator of tyrosinase. Furthermore, Western blot analysis showed that scopoletin stimulated the production of microphthalmia-associated transcription factor (MITF) and tyrosinase expression via cAMP response element-binding protein (CREB) phosphorylation in a dose-dependent manner. Based on these results, preclinical and clinical studies are needed to assess the use of scopoletin for the treatment of vitiligo.

Menadione (Vitamin K3) decreases melanin synthesis through ERK activation in Mel-Ab cells.

Menadione is a synthetic vitamin K3 derivative. Here, we examined the effects of menadione on melanogenesis and its related signaling pathways. Our results showed that melanin content was significantly reduced after menadione treatment in a dose-dependent manner. However, menadione treatment did not reduce tyrosinase activity directly. Wnt signaling is known to play a major role in the control of melanin synthesis. Thus, we tested the effects of menadione treatment on GSK3ß and ß-catenin signaling, but found that menadione did not influence either of these signaling pathways. We also investigated changes in the phosphorylation of ERK, which is related to melanin regulation. These results indicated that menadione treatment led to the phosphorylation of ERK. Additionally, menadione treatment reduced both MITF and tyrosinase protein levels. Treatment with PD98059, a specific ERK pathway inhibitor, restored menadione-induced melanin reduction and also prevented MITF and tyrosinase downregulation by menadione. These results suggest that the hypopigmentary action of menadione is due to MITF and tyrosinase downregulation by ERK activation.

Geranylgeranylacetone inhibits melanin synthesis via ERK activation in Mel-Ab cells.

AIMS: Geranylgeranylacetone (GGA) has shown cytoprotective activity through induction of a 70-kDa heat shock protein (HSP70). Although HSP70 is reported to regulate melanogenesis, the effects of GGA on melanin synthesis in melanocytes have not been previously studied. Therefore, this study investigated the effects of GGA on melanogenesis and the related signaling pathways. MAIN METHODS: Melanin content and tyrosinase activities were measured in Mel-Ab cells. GGA-induced signal transduction pathways were investigated by western blot analysis. KEY FINDINGS: Our results showed that GGA significantly decreased melanin content in a concentration-dependent manner. Similarly, GGA reduced tyrosinase activity dose-dependently, but it did not directly inhibit tyrosinase. Western blot analysis indicated that GGA downregulated microphthalmia-associated transcription factor (MITF) and tyrosinase protein expression, whereas it increased the phosphorylation of extracellular signal-regulated kinase (ERK) and mammalian target of rapamycin (mTOR). Furthermore, a specific ERK pathway inhibitor, PD98059, blocked GGA-induced melanin reduction and then prevented downregulation of MITF and tyrosinase by GGA. However, a specific mTOR inhibitor, rapamycin, only slightly restored inhibition of melanin production by GGA, indicating that mTOR signaling is not a key mechanism regulating the inhibition of melanin production. SIGNIFICANCE: These findings suggest that activation of ERK by GGA reduces melanin synthesis in Mel-Ab cells through downregulation of MITF and tyrosinase expression.

Dipeptides Inhibit Melanin Synthesis in Mel-Ab Cells through Down-Regulation of Tyrosinase.

This study investigated the effects of proline-serine (PS) and valine-serine (VS) dipeptides on melanogenesis in Mel-Ab cells. Proline-serine and VS significantly inhibited melanin synthesis in a concentration-dependent manner, though neither dipeptide directly inhibited tyrosinase activity in a cell-free system. Both PS and VS down-regulated the expression of microphthalmia-associated transcription factor (MITF) and tyrosinase. In a follow-up study also described here, the effects of these dipeptides on melanogenesis-related signal transduction were quantified. Specifically, PS and VS induced ERK phosphorylation, though they had no effect on phosphorylation of the cAMP response element binding protein (CREB). These data suggest that PS and VS inhibit melanogenesis through ERK phosphorylation and subsequent down-regulation of MITF and tyrosinase. Properties of these dipeptides are compatible with application as skin-whitening agents.

Transplantation of human adipose-derived stem cells in a rabbit model of traumatic degeneration of lumbar discs.

OBJECTIVE: The purpose of the present study is to assess the possibility of disc regeneration by treatment with adipose-derived stem cells (ADSCs) in a rabbit model of degenerative disc disease, and to evaluate the efficacy of a percutaneous technique for constructing a model of degenerative disc disease in rabbits. METHODS: The study sample consisted of 20 mature male New Zealand white rabbits. Intervertebral discs were injured in each rabbit by a percutaneous technique at L2-3, L3-4, and L4-5 under C-arm guidance with a 19-gauge spinal needle. Magnetic resonance images (MRI) were checked at 6, 9, 12, and 15 weeks after injury to evaluate disc degeneration. Nineteen weeks after injury, ADSCs were injected into the L4-5 disc space, with saline injected into the L3-4 disc as a control, using a 21-gauge spinal needle. Histologic confirmations of degenerated discs were performed at 10 and 18 weeks after injury with safranin O and trichrome stains. RESULTS: MRI revealed intervertebral disc degeneration from 9 weeks after injury, and full degeneration at 15 weeks after injury, when compared with uninjured control discs. We confirmed the proliferation of ADSCs at the L4-5 level in 10-week rabbits after cell injection. Histologically, the ADSC-injected discs exhibited elevated extracellular matrix secretion and little ossification of damaged cartilage in the nucleus pulposus compared with degenerative control discs. CONCLUSIONS: These results suggest that the injection of ADSCs into injured lumbar discs could be an effective treatment for degenerative disc disease by promoting the cartilage regeneration.

Farnesoid X receptor protects hepatocytes from injury by repressing miR-199a-3p, which increases levels of LKB1.

BACKGROUND & AIMS: Hepatocyte injury occurs during liver fibrogenesis. MicroRNAs (miRNA) regulate some of these processes, and some are regulated by the farnesoid X receptor (FXR). We investigated the effect of repression of specific miRNAs by FXR in hepatocyte injury using fibrotic liver tissue from patients and hepatocytes. METHODS: We used immunohistochemistry or real-time polymerase chain reaction to analyze proteins and miRNAs in human and mouse liver samples. HepG2 cells were transfected with pre-miRNA, antisense oligonucleotides, small interfering RNAs, the 3'-untranslated region of liver kinase B1 (LKB1) (STK11), or constructs for overexpression, and analyzed. RESULTS: Liver tissue from patients with severe fibrosis had lower levels of FXR and greater amounts of hepatocyte death than samples from patients with mild disease. Levels of several miRNAs changed when FXR expression was disrupted in the liver; one of these, miR-199a-3p, was significantly up-regulated in patients with severe fibrosis. Activation of FXR by its ligand reduced the level of miR-199a-3p in HepG2 cells. LKB1 messenger RNA was identified as a target of miR-199a-3p, and its expression was reduced in human fibrotic liver tissue. Overexpression of FXR or incubation of cultured hepatocytes with the FXR ligand up-regulated LKB1; LKB1 was not induced in cells transfected with miR-199a-3p. Incubation of HepG2 cells with FXR ligand, or injection of the ligand into mice, protected hepatocytes from injury and increased levels of LKB1; levels of miR-199a-3p were reduced compared with cells that were not incubated with the FXR ligand. Activation of FXR reduced mitochondrial dysfunction and oxidative stress and increased hepatocyte survival. CONCLUSIONS: In hepatocytes, FXR represses production of miR-199a-3p. In fibrotic livers of humans and mice, FXR expression is reduced, increasing levels of miR-199a-3p, which reduces levels of LKB1. FXR therefore protects hepatocytes from injury by repressing miR-199a-3p and thereby increasing levels of LKB1.

Effects of statin and deferoxamine administration on neurological outcomes in a rat model of intracerebral hemorrhage.

Deferoxamine (DFX), a potent iron-chelating agent, reduces brain edema and neuronal cell injury that develop due to the hemolysis cascade. Statins have neuroprotective effects via anti-inflammatory action and increment of cerebral blood flow after intracerebral hemorrhage (ICH). The purpose of this study was to identify the effects of combined DFX and statins treatment in an experimental ICH rat model. The treatments were: intraperitoneal (i.p.) injection of DFX (group I), combined treatment of i.p. DFX and oral statins (group II), statins only (group III) and treatment with vehicle (group IV). Induction of ICH was performed with injection of bacterial collagenase type IV into the left striatum. After removal of the brain, hematoma volume, water content and brain atrophy were measured. Immunohistochemistry in the perihematomal region was performed for identification of microglial infiltration, astrocyte expression and apoptotic cell presence. Statistical analysis was performed using the non-parametric Kruskal-Wallis test and significance was evaluated when the p value was less than 0.05. According to behavioral tests, significant differences among treatment groups were noted 4 weeks after ICH induction (p < 0.05). However, there were no significant differences among treatment groups in hematoma volume, brain water content or brain atrophy. In the perihematomal area, the activated microglial cells were reduced in the combined treatment group. Among the four groups, a significant difference in immunohistochemical staining was identified (p < 0.05). These results suggest that combined treatment with DFX and statins improves neurologic outcomes after ICH through reduction of microglial infiltration, apoptosis, inflammation and brain edema.

Validation of a simple computerized tool for measuring spinal and pelvic parameters.

OBJECT: Recent studies have emphasized measuring the sagittal vertical axis (SVA) and pelvic parameters (pelvic incidence, sacral slope, and pelvic tilt) when evaluating spinal disorders. An accurate and reproducible measurement is important for a reliable result. Although computerized measurement is more consistent than manual measurement, computerized measurement requires an expensive software program, the need to transfer images to a workstation, and additional education for users. An inexpensive and convenient computerized measurement program is desirable and necessary. The object of this study was to propose a computerized tool for measuring spinal and pelvic parameters and to evaluate the efficacy of this new tool compared with manual measurement. METHODS: The authors devised a tool that provides computerized measurements of the SVA and pelvic parameters in a picture archiving and communication system (PACS) without transferring images to another program. This tool was created by merging functions in the PACS. The resulting tool is easy to implement by merging functions (indicate the center of 2 points, plot a vertical and a horizontal line from a point, and measure the angles between lines) in any image viewer. The tool was made into icons on a toolbar in the PACS. Measurements of distance and angle were computerized by identifying crucial points after selecting the icon. For SVA, 4 points were identified around each corner of the C-7 body and a fifth point at the superior/posterior corner of the S-1 body. For pelvic parameters, 4 points were identified at the centers of each femoral head and at the anterior/superior and posterior/superior corners of S-1. Thirty-three whole-spine lateral radiographs were randomly selected from the radiographic database. To evaluate inter- and intraobserver variability between observers and method, skilled (2 years of experience) and unskilled (1 week of experience) observers measured SVA and pelvic parameters 3 times with a 7-day interval between each time using both computerized and manual measurement methods. The reliability was measured using the intraclass correlation coefficient. RESULTS: The computerized method showed better congruity than the manual method in both skilled and unskilled observers (p < 0.05), and the intraclass correlation coefficients were > 0.9. The skilled observer showed better agreement than the unskilled observer with both computerized and manual methods, and this difference was prominent in measuring pelvic parameters (p < 0.05). The computerized method required less time than the manual method, especially for the unskilled observer (p < 0.05). CONCLUSIONS: A computerized measurement of pelvic parameters may be a more reliable and efficacious approach than manual measurements. This benefit is more prominent in the unskilled observer, and adding this simple function to an image viewer may be recommended in future studies.

The expression of corticotropin-releasing factor and its receptors in the spinal cord and dorsal root ganglion in a rat model of neuropathic pain.

Corticotropin-releasing factor (CRF) is a peptide involved in the activation of the hypothalamic-pituitary-adrenal (HPA) axis. CRF is distributed not only along the HPA axis but also throughout pain-relevant anatomical sites. CRF elicits potent antinociception at the three main levels of pain transmissions: namely, the brain, spinal cord, and peripheral sensory neurons. The widespread distribution of CRF receptors 1 and 2 in the brain offers several targets wherein CRF could alter pain, some of which may be independent of the HPA axis. In this study, we assessed the expression of CRF and its receptors, CRF receptor type (CRFR)1 and CRFR2, in the spinal dorsal horn and dorsal root ganglion (DRG) in a rat model of neuropathic pain induced by spinal nerve injury (SNI). CRF was expressed in a few DRG neurons and primary afferent fibers in the dorsal horns of naїve rats, and the CRF-positive neurons in DRG and fibers in the spinal dorsal horn were found to have increased after SNI. CRFR1 was not expressed in DRG or the dorsal horn and CRFR2 was expressed weakly in the small neurons in DRG in the naїve rats. After SNI, CRFR1 was expressed in the activated microglia in the ipsilateral dorsal horn, and immunoreaction for CRFR2 was increased in the contralateral DRG following SNI. Consequently, it has been suggested that the increased expression of CRF and CRFR2 in DRG neurons and primary afferent fibers in dorsal horn, and CRFR1 in the activated microglia, may be involved in the mediation of stress responses as well as in microglial activation in the neuropathic pain state following SNI.

Ajoene, a stable garlic by-product, inhibits high fat diet-induced hepatic steatosis and oxidative injury through LKB1-dependent AMPK activation.

Hepatic steatosis, a hepatic component of metabolic syndrome, is common and may progress to steatohepatitis and cirrhosis. The liver X receptor-α (LXRα)-sterol regulatory element binding protein-1c (SREBP-1c) pathway plays a key role in hepatic steatosis. This study investigated the potential of ajoene, a stable garlic by-product, to inhibit high fat diet (HFD)-induced hepatic steatosis and the underlying mechanism. Ajoene treatment attenuated fat accumulation and induction of lipogenic genes in the liver of HFD-fed mice. Blood biochemical analyses and histopathologic examinations showed that ajoene prevented liver injury with the inhibition of oxidative stress, as evidenced by thiobarbituric acid reactive substances formation and nitrotyrosinylation. Moreover, ajoene treatment inhibited LXRα agonist (T0901317)-mediated SREBP-1c activation, and transactivation of the lipogenic target genes in hepatocytes. Ajoene was found to activate AMP-activated protein kinase (AMPK) via LKB1, responsible for the inhibition of p70 ribosomal S6 kinase-1 (S6K1). The ability of ajoene to repress T0901317-induced SREBP-1c expression was antagonized by inhibition of AMPK or activation of S6K1, supporting the role of these kinases in the antisteatotic effect. Our results demonstrate that ajoene has an effect of activating AMPK through LKB1 and inhibit S6K1 activity, contributing to the prevention of SREBP-1c-mediated hepatic lipogenesis via the inhibition of LXRα activity.

E-cadherin antagonizes transforming growth factor ß1 gene induction in hepatic stellate cells by inhibiting RhoA-dependent Smad3 phosphorylation.

UNLABELLED: Cadherins mediate cell-cell adhesion and catenin (ctn)-related signaling pathways. Liver fibrosis is accompanied by the loss of E-cadherin (ECAD), which promotes the process of epithelial-mesenchymal transition. Currently, no information is available about the inhibitory role of ECAD in hepatic stellate cell activation. Because of ECAD's potential for inhibiting the induction of transforming growth factor ß1 (TGFß1), we investigated whether ECAD overexpression prevents TGFß1 gene induction; we also examined what the molecular basis could be. Forced expression of ECAD decreased α-smooth muscle actin and vimentin levels and caused decreases in the constitutive and inducible expression of the TGFß1 gene and its downstream genes. ECAD overexpression decreased Smad3 phosphorylation, weakly decreased Smad2 phosphorylation, and thus inhibited Smad reporter activity induced by either treatment with TGFß1 or Smad3 overexpression. Overexpression of a dominant negative mutant of ras homolog gene family A (RhoA) diminished the ability of TGFß1 to elicit its own gene induction. Consistently, transfection with a constitutively active mutant of RhoA reversed the inhibition of TGFß1-inducible or Smad3-inducible reporter activity by ECAD. Studies using the mutant constructs of ECAD revealed that the p120-ctn binding domain of ECAD was responsible for TGFß1 repression. Consistently, ECAD was capable of binding p120-ctn, which recruited RhoA; this prevented TGFß1 from increasing RhoA-mediated Smad3 phosphorylation. In the liver samples of patients with mild or severe fibrosis, ECAD expression reciprocally correlated with the severity of fibrosis. CONCLUSION: Our results demonstrate that ECAD inhibits Smad3/2 phosphorylation by recruiting RhoA to p120-ctn at the p120-ctn binding domain, whereas the loss of ECAD due to cadherin switching promotes the up-regulation of TGFß1 and its target genes, and facilitates liver fibrosis.

Neurochemical Characterization of the TRPV1-Positive Nociceptive Primary Afferents Innervating Skeletal Muscles in the Rats.

OBJECTIVE: Transient receptor potential vanilloid subfamily type 1 (TRPV1), a most specific marker of the nociceptive primary afferent, is expressed in peptidergic and non-pepetidergic primary afferents innervating skin and viscera. However, its expression in sensory fibers to skeletal muscle is not well known. In this study, we studied the neurochemical characteristics of TRPV1-positive primary afferents to skeletal muscles. METHODS: Sprague-Dawley rats were injected with total 20 microl of 1% fast blue (FB) into the gastrocnemius and erector spinae muscle and animals were perfused 4 days after injection. FB-positive cells were traced in the L4-L5 (for gastrocnemius muscle) and L2-L4 (for erector spinae muscle) dorsal root ganglia. The neurochemical characteristics of the muscle afferents were studied with multiple immunofluorescence with TRPV1, calcitonin gene-related peptide (CGRP) and P2X(3). To identify spinal neurons responding to noxious stimulus to the skeletal muscle, 10% acetic acids were injected into the gastrocnemius and erector spinae muscles and expression of phospho extracellular signal-regulated kinase (pERK) in spinal cords were identified with immunohistochemical method. RESULTS: TRPV1 was expressed in about 49% of muscle afferents traced from gastrocnemius and 40% of erector spinae. Sixty-five to 60% of TRPV1-positive muscles afferents also expressed CGRP. In contrast, expression of P2X(3) immnoreaction in TRPV1-positive muscle afferents were about 20%. TRPV1-positive primary afferents were contacted with spinal neurons expressing pERK after injection of acetic acid into the muscles. CONCLUSION: It is consequently suggested that nociception from skeletal muscles are mediated by TRPV1-positive primary afferents and majority of them are also peptidergic.