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Y2O3:Eu thin films were deposited on p-type (100)-oriented silicon wafers by using the radiofrequency (RF) magnetron sputter deposition technique and then post-annealed in an air ambient at various temperatures and holding times. X-ray diffraction data showed that the as-deposited films had a cubic Y2O3 structure textured with the (222) plane. The as-deposited films were found to be under internal compressive stress, and the annealing treatment led to relaxation of the stress in the films. Photoluminescence (PL) was observed from the films annealed at temperatures ≥ 400°C, and the strongest peak occurred at 613 nm in the red range. The PL intensity increased as the annealing temperature was increased, resulting from the improved crystalline quality of the Y2O3:Eu films annealed at higher temperatures. The PL intensity reached a maximum at 1200°C and then decreased due to the formation of the Y2SiO5 phase. The Y2O3:Eu films were also annealed at 1200°C for different periods of time from 1 to 10 h. The PL intensity of the 1200°C-annealed films was decreased for longer holding time resulting from the formation of the Y2SiO5 phase.

This study was designed to investigate (i) extracellular matrix to specify adhesive substrates to human dura mater cell (hDMC); (ii) the alteration on adhesion-related molecules in hDMC; and (iii) secreted matrix metalloproteinases (MMPs) linked with extracellular matrix remodeling after exposure to inflammation. The hDMC was cultured from human dura mater tissue, and the studies were performed with hDMC after co-culturing with macrophage like THP-1 cells (Mϕ). The adhesion of co-cultured hDMC through collagen I increased 6.4-fold and through collagen IV increased 5.0-fold compared with the adhesion of naive cells (p < 0.001). Integrin subtype α2 β1 expression was increased 6.3-fold (p < 0.001) and α1 expression was decreased 2.0-fold (p < 0.001) in the co-cultured cells compared with the naive cells. Co-culturing induced significant increases in MMP-1 (13.9-fold, p < 0.01), MMP-3 (7.6-fold, p < 0.01), and VEGF (VEGF: 3.8-fold, p < 0.05) expression and decreases in MMP-9 (0.1-fold, p < 0.01) compared with the sum of naive hDMC and Mϕ values. Increased hDMC adhesion under inflammatory conditions is caused by an increased cellular affinity for collagen I and IV mediated by increased hDMC levels of integrin subtype α2 β1 and environmental MMP-1, -3 and decreased MMP-9. Selective integrin subtype α2 β1 inhibition assay showed 37.8% and 35.7% reduction in adhesion of co-cultured hDMC to collagen I (p < 0.001) and IV (p = 0.057), respectively. The present study provides insight into the pathological conditions related to dura mater adhesion in inflammation. © 2018 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 9999:1-11, 2019.

To evaluate dominant cell-to-cell paracrine interactions, including those of human annulus fibrosus (AF), nucleus pulposus (NP), and endothelial cells (ECs), in the production of inflammatory mediators and catabolic enzymes, ECs was cultured in soluble factors derived from AF or NP cells (AFCM or NPCM, respectively) and vice versa. We analysed IL-6 and -8, vascular endothelial growth factor (VEGF), matrix metalloproteinase (MMP)-1 and -3, nerve growth factor (NGF)-β, and brain-derived neurotrophic factors (BDNFs) with qRT-PCR and ELISA. We implement a microfluidic platform to analyse migration properties of AF and NP cells and ECs in 3D cultures. Our results show that IL-1β-stimulated AF cells produced significantly higher levels of IL-6 and -8, VEGF, and MMP-1 than IL-1β-stimulated NP cells. However, production of IL-6 and -8, VEGF, and MMP-3 was significantly higher in NP cells than in AF cells, under the presence of ECs conditioned medium. We observed considerable migration of NP cells co-cultured with ECs through the microfluidic platform. These results suggest that AF cells may play a major role in the initial degeneration of intervertebral disc. Furthermore, it was found that interactions between NP cells and ECs may play a significant role in the development or progression of diseases.

Highly transparent yttrium oxide thin films doped with europium (Y2O3:Eu) were fabricated and their optical, luminescent, and structural properties were investigated. Thin films of Y2O3:Eu were deposited on fused quartz substrates by using a radio-frequency (RF) magnetron sputtering method and subsequently annealed at 1000 °C for 1 hour in air atmosphere. The resultant Y2O3:Eu films showed a high optical transmittance, greater than 82%, in the visible wavelength range above 400 nm and up to 92% transmittance in the near-infrared range. The optical band gap of the films was determined to be approximately 5.77 eV. The refractive index of the films ranged between 1.854 and 1.767 in the visible wavelength region from 400 to 700 nm. X-ray diffraction (XRD) measurements revealed that the films had a cubic crystal structure of Y2O3 and were strongly textured along the [100] direction. The Y2O3:Eu films exhibited a red photoluminescence emission with a dominant peak centered at around 612 nm due to the 5D0 → 7F2 transition of Eu3+ ion. The excitation spectrum showed a broad band in the ultraviolet (UV) wavelength region corresponding to the O2−−Eu3+ charge transfer band.

Electrical stimulation of cells and tissues for therapeutic benefit is a well-established method. Although animal studies can emulate the complexity of an organism’s physiology, lab-on-a-chip platforms provide a suitable primary model for follow-up animal studies. Thus, inexpensive and easy-to-use platforms for in vitro human cell studies are required. In the present study, we designed a micro-electrical impulse (micro-EI)-on-a-chip (micro-EI-chip), which can precisely control electron density and adjust the frequency based on a micro-EI. The micro-EI-chip can stimulate cells at various micro-EI densities (0–500 mV/mm) and frequencies (0–300 Hz), which enables multiple co-culture of different cell types with or without electrical stimulation. As a proof-of-concept study, a model involving degenerative inflamed human annulus fibrosus (hAF) cells was established in vitro and the effects of micro-EI on inflamed hAF cells were evaluated using the micro-EI-chip. Stimulation of the cells (150 mV/mm at 200 Hz) inhibited the secretion of inflammatory cytokines and downregulated the activities of extracellular matrix-modifying enzymes and matrix metalloproteinase-1. These results show that micro-EI stimulation could affect degenerative diseases based on inflammation, implicating the micro-EI-chip as being useful for basic research of electroceuticals.

Destruction of extracellular matrix (ECM) leads to degeneration of the intervertebral disk (IVD), which is a major contributor to many spine disorders. IVD degeneration is induced by pro-inflammatory cytokines, such as tumor necrosis factor-alpha (TNF-α) and interleukin-1 beta (IL-1β), which are secreted by immune cells, including macrophages and neutrophils. The cytokines modulate ECM-modifying enzymes such as matrix metalloproteinases (MMPs) and tissue inhibitors of metalloproteinases (TIMPs) in human annulus fibrosus (AF) cells. The resulting imbalance in catabolic and anabolic enzymes can cause generalized back, neck, and low back pain (LBP). Photobiomodulation (PBM) is known to regulate inflammatory responses and wound healing. The aim of this study was to mimic the degenerative IVD microenvironment, and to investigate the effect of a variety of PBM conditions (wavelength: 635, 525, and 470 nm; energy density: 16, 32, and 64 J/cm(2)) on the production of ECM-modifying-enzymes by AF cells under degenerative conditions induced by macrophage-conditioned medium (MCM), which contains pro-inflammatory cytokines such as TNF-α and IL-β secreted by macrophage during the development of intervertebral disk inflammation. We showed that the MCM-stimulated AF cells express imbalanced ratios of TIMPs (TIMP-1 and TIMP-2) and MMPs (MMP-1 and MMP-3). PBM selectively modulated the production of ECM-modifying enzymes in AF cells. These results suggest that PBM can be a therapeutic tool for degenerative IVD disorders.

Intervertebral disc (IVD) degeneration is associated with imbalances between catabolic and anabolic responses, regulated by extracellular matrix (ECM)-modifying enzymes such as matrix metalloproteinases (MMPs) and their endogenous tissue inhibitors of metalloproteinases (TIMPs). Potential contributing factors, such as interleukin (IL)-1β and tumor necrosis factor (TNF)-α, derived from infiltrated, activated macrophages within IVD tissues, can trigger abnormal production of ECM-modifying enzymes and progression of IVD degeneration. Novel therapies for regulating ECM-modifying enzymes can prevent or ameliorate IVD degeneration. Photobiomodulation (PBM), known to regulate wound repair, exhibits regenerative potential by modulating biological molecules. This study examined the effects of PBM, administered at various wavelengths (630, 525, and 465 nm) and energy densities (16, 32, and 64 J/cm2), on the production of ECM-modifying enzymes in replicated degenerative IVD. Our results showed that PBM selectively inhibited the production of ECM-modifying enzymes in a dose- and wavelength-dependent manner, suggesting that it could be a novel tool for treating symptomatic IVD degeneration.

BACKGROUND Biochemical alterations associated with mechanical stress have been explored as an initiating step in the pathological progression of ligamentum flavum hypertrophy (LFH); however, this mechanism remains poorly understood. Recently, the inflammation induced after mechanical stress and the subsequent response of ligamentum flavum (LF) cells have been implicated in LFH pathology. OBJECTIVE To investigate the hypothesis that angiogenesis may be a critical link between hypertrophy and a series of stimulating events, including mechanical stress. METHODS LF from 20 lumbar spinal canal stenosis (LSCS) patients and 16 non-LSCS patients (control group) were collected during surgery. Patient demographic and radiographic data were obtained. The levels of angiogenic factors (vascular endothelial growth factor [VEGF], angiopoietin-1, vascular cell adhesion molecule, and basic fibroblast growth factor) in the LF were investigated by using an enzyme-linked immunosorbent assay. Angiogenesis was also quantified by immunohistochemical detection of CD34-positive capillaries. The correlations among clinical factors, including radiographic factors, angiogenic factors, and angiogenesis, were statistically analyzed. RESULTS The LSCS group was older and exhibited a longer symptom duration, wider segmental motion, and thicker LF than the control group. The LSCS group showed significantly higher tissue concentrations of VEGF (P < .001) that positively correlated with LF thickness (r = 0.557, P < .001) and segmental motion (r = 0.586, P < .001). The LSCS group showed significantly more CD34-positive capillaries than the control group (P = .004). CONCLUSION The LSCS group showed greater segmental motion, higher VEGF concentrations, and more CD34-positive capillaries than the control group. These data indicate that VEGF-mediated angiogenesis following mechanical stress may be a critical step within the series of pathological events in LFH.

Intervertebral disc degeneration (IVD) is one of the important causes of low back pain and is associated with inflammation induced by interaction between macrophages and the human annulus fibrosus (AF) cells. Low-level light therapy (LLLT) has been widely known to regulate inflammatory reaction. However, the effect of LLLT on macrophage-mediated inflammation in the AF cells has not been studied till date. The aim of this study is to mimic the inflammatory microenvironment and to investigate the anti-inflammatory effect of LLLT at a range of wavelengths (405, 532 and 650 nm) on the AF treated with macrophage-like THP-1 cells conditioned medium (MCM) containing proinflammatory cytokines and chemokines (interleukin-1beta, tumor necrosis factor-alpha, interleukin-6 and 8). We observed that AF cells exposed to MCM secrete significantly higher concentrations of IL-6, IL-8, IL-1β and TNF-α. LLLT markedly inhibited secretion of IL-6 at 405 nm in a time-dependent manner. Level of IL-8 was significantly decreased at all wavelengths in a time-dependent manner. We showed that MCM can induce the inflammatory microenvironment in AF cells and LLLT selectively suppressed IL-6 and 8 levels. The results indicate that LLLT is a potential method of IVD treatment and provide insights into further investigation of its anti-inflammation effect on IVD.

The etiology of intervertebral disc (IVD) degeneration accompanied by low back pain (LBP) is largely unknown, and there are no curative therapies. Painful IVD degeneration is associated with infiltrated macrophage-mediated inflammatory response of human nucleus pulposus (NP) cells. The present study aimed to address the hypothesis that pro-inflammatory cytokines derived from macrophages lead to the altered molecular phenotype of human NP cells and to investigate the effects of phototherapy (630, 525, 465 nm with 16, 32, 64 J/cm2) on pain-related cytokine interleukin (IL)-6 and chemokine IL-8 under inflammatory conditions in human NP cells. Human NP cells were treated with soluble factors derived from macrophages in an inflammatory microenvironment, similar to that found in degenerative IVD. Human NP cells were also treated with phototherapy (630, 525, 465 nm with 16, 32, 64 J/cm2), and their cytokine and chemokine levels were detected. The soluble factors caused modulated expression of IL-6, IL-8, and matrix metalloproteinases (MMPs) at the gene and protein levels, causing a shift toward matrix catabolism through the expression of MMPs and increased pain-related factors via preferential activation of the nuclear factor-kappa B (NF-κB) p50 protein. Importantly, phototherapy attenuated the protein and gene expression of pain-related factor IL-6 at all doses and wavelengths. Interestingly, phototherapy also modulated the protein and gene expression of IL-8, which is responsible for the anabolic response, at a wavelength of 465 nm at all doses, in human NP cells. These findings suggested that phototherapy, at an optimal dose and wavelength, might be a useful therapeutic tool to treat IVD degeneration.

The structure and the properties of gallium nitride (GaN) thin films prepared by using a radiofrequency (RF) magnetron sputtering method are reported. The GaN thin films were deposited on p-type (111)-oriented silicon substrates at room temperature in a pure nitrogen atmosphere. X-ray photoelectron spectra showed that the films were mainly composed of gallium and nitrogen. An oxygen impurity was found to be incorporated into the films during the deposition. The refractive index of the GaN films was measured to be 2.36 at a wavelength of 633 nm. The optical bandgap of the GaN films was determined to be approximately 3.31 eV. From the grazing incidence X-ray reflectivity measurements, the density and the surface roughness of the GaN films were estimated to be 5.827 g/cm3 and 2.95 nm, respectively. The X-ray diffraction analysis revealed that the crystalline phase of the GaN films changed from wurtzite to zinc-blende as the working gas pressure was reduced. The observed phase change was found to be independent of the orientation of the Si substrate, but to be strongly correlated with the biaxial compressive stress.

Background The intervertebral disc (IVD) is an avascular structure, and is therefore stable under hypoxic conditions. Previous studies have demonstrated that hypoxia might be related to symptomatic degenerative disc diseases (DDDs); however, the pathomechanism is still poorly understood. Objective To identify the effect of hypoxia on the production of inflammatory mediators, angiogenic factors, and extracellular matrix-regulating enzymes of IVD cells during inflammatory reactions. Methods Human nucleus pulposus (NP) and annulus fibrosus (AF) cells harvested during surgery for DDDs were cultured in macrophage conditioned media or interleukin (IL)-1β-stimulated media under hypoxic (2%) and normoxic (21%) conditions. Hypoxia-inducible factor-1α transcription factor activation was analyzed by western blotting. IL-6, IL-8, vascular endothelial growth factor (VEGF), vascular cell adhesion molecule (VCAM), matrix metalloproteinase (MMP)-1, MMP-3, tissue inhibitor of metalloprotease (TIMP)-1, and TIMP-2 in conditioned media were measured by an enzyme-linked immunosorbent assay. Results NP cells expressed higher hypoxia-inducible factor-1α in the IL-1β-stimulated group under hypoxic condition. MMP-1 was significantly increased in the AF cells under hypoxic condition; TIMP-1 and TIMP-2 were significantly decreased in both naive NP and AF cells during hypoxia. Both cells in macrophage conditioned media significantly diminished the production of IL-6 and VCAM, while VEGF significantly increased during hypoxia. After 1 ng/mL IL-1β stimulation, IL-8, VEGF, MMP-1, and MMP-3 were significantly increased in both cell types during hypoxia, while VCAM, TIMP-1, and TIMP-2 were decreased. Conclusion We found that hypoxia can enhance the angiogenic ability of IVD during inflammatory reactions, and cause progress in development of DDD via extracellular matrix regulation in this in vitro study.

Study design In vitro study about angiogenic potentiality of ligamentum flavum (LF) cells using coculture of human lumbar LF cells and activated macropage-like THP-1 cells. Objective To test our hypothesis that activated LF, which was exposed to inflammation, induces angiogenesis, thus resulting in hypertrophy. Summary of background data Inflammatory reactions after mechanical stress produce fibrosis and scarring of the LF that result in hypertrophy, a major pathological feature of spinal stenosis. This study evaluated the roles of LF cells in the pathomechanism of hypertrophy, focusing on angiogenesis. Methods To determine their response to the inflammatory reaction, human LF cells were cocultured with phorbol myristate acetate-stimulated macrophage-like THP-1 cells. The conditioned media were assayed for tumor necrosis factor (TNF)-α, interleukin (IL)-1β, IL-6, IL-8, vascular endothelial growth factor (VEGF), and transforming growth factor (TGF)-β1. Naive and macrophage-exposed LF cells that responded to TNF-α/IL-1β were compared using the same outcome measures. Hypertrophied LF tissue was stained by TGF-β1 primary antibody using immunohistochemical method. Results Larger quantities of IL-6, IL-8, and VEGF were secreted by cocultured cells than by macrophages alone and LF cells alone combined. Prior macrophage exposure increased the secretion of IL-8 and VEGF in response to TNF-α/IL-1β stimulation whereas IL-6 production was increased in response to IL-1β. The coculture appeared to increase TGF-β1 secretion but the level was lower than that for macrophage-like cells alone and LF cells alone combined. Conclusion LF cells interact with macrophage-like cells to produce angiogenesis-related factors except TGF-β1. Activated LF cells that have been exposed to macrophage, can impact the inducement of angiogenesis-related factors, suggesting that fibrosis and scarring during inflammatory reaction is the major pathomechanism of LF hypertrophy.

Thin films of zinc germanate doped with manganese (Zn 2 GeO 4 :Mn) were fabricated by radio frequency magnetron sputtering, and their structural characteristics and luminescent properties were studied. The Zn 2 GeO 4 :Mn films exhibited a pronounced absorption edge at around 271 nm and a high optical transparency in the visible wavelength region with a peak transmittance of 0.927 at 691 nm. While the as-deposited Zn 2 GeO 4 :Mn films had an amorphous structure, the annealed films possessed a rhombohedral polycrystalline structure with a random crystallographic orientation of grains. The broad-band photoluminescence (PL) emission was observed from the annealed Zn 2 GeO 4 :Mn films. The PL emission spectrum showed a peak maximum at around 537 nm in the green range, which was accounted for by the intrashell transition of 3 d 5 orbital electrons from the 4 T 1 lowest excitation state to the 6 A 1 ground state in the divalent manganese ions. Two discrete peaks were observed in the PL excitation spectrum at 256 and 296 nm, which are considered to be associated with the band-to-band absorption of the host and the sub-band absorption from defect states, respectively. The green cathodoluminescence (CL) emission was obtained from the annealed Zn 2 GeO 4 :Mn films with a peak centered at around 534 nm, analogous to the PL emission spectrum.

Thin films of Ga2O3:Mn have been deposited on silicon (100) substrates without intentional heating by radio frequency (RF) planar magnetron sputtering from a Mn-doped Ga2O3 target in an oxygen-argon mixture atmosphere. Microstructure and properties of the deposited Ga2O3:Mn films were systematically investigated as a function of the post-deposition annealing temperature in the range between 500 °C and 1200 °C. X-ray diffraction (XRD) measurements showed that the as-deposited Ga2O3:Mn films were of an amorphous structure in nature. The Ga2O3:Mn films became crystalline by the post-deposition annealing above 800 °C and the crystallinity of the films was continuously improved up to the annealing temperature of 1200 °C. It was shown that the annealed Ga2O3:Mn films possessed a monoclinic β-Ga2O3 phase having a textured structure with (400) and (−401) crystallographic planes oriented preferentially parallel to the substrate surface. The lattice parameters of the monoclinic β-Ga2O3 phase in the 1200 °C annealed Ga2O3:Mn films were measured to be a = 12.152 A, b = 3.043 A, and c = 5.785 A.

Four new dopant materials containing a monostyrylamine moiety, 4-(1,2-diphenylvinyl)-4′-(N,N-diphenylamino)biphenyl (TP-BP), 4-(1,2-diphenylvinyl)-4′-(N,N-ditolylamino)biphenyl (TP-MP), 4-(1,2-diphenylvinyl)-4′-(N-naphthyl-N-phenylamino)biphenyl (TP-NP) and 4-[1-phenyl-2-(4-biphenyl)vinyl]-4′-(N,N-diphenylamino)biphenyl (TP-BiP) were synthesized by the Wittig–Horner reaction, followed by an amination reaction with various aromatic diamines. Blue OLEDs were obtained from the distyrylarylene host materials TPM-BP, TPM-MP and TPM-BiP. The structure of the device is an ITO/DNTPD/NPB/TPM host, TP dopant/Alq3/Al–LiF. Here, NPB is used as the hole transport layer, DNTPD as the hole injection layer, the TPM series host as the blue emitting host, TP series as dopant, Alq3 as the electron transport layer, and Al as the cathode. Their photophysical and electroluminescent properties, including efficiency, current density, and CIE coordinates were examined.

Cubic gallium nitride (GaN) thin films were grown at room temperature on silicon (100)-oriented substrates by radio frequency (rf) planar magnetron sputtering of a GaN target in a pure nitrogen atmosphere. The rf power applied to the GaN cathode target was varied in order to determine the influence of film growth rate on the texture and properties of cubic GaN films. The growth rate of the GaN films was an approximately linear function of the rf cathode target power. X-ray diffraction θ–2θ and pole-figure scans revealed that all the GaN films possess a predominant cubic zinc-blende phase having a textured structure with (111) crystallographic planes oriented preferentially parallel to the surface. The a lattice parameter of the cubic GaN was determined to be approximately 4.59 A. X-ray rocking curve analysis showed that the degree of [111] preferred orientation is higher for the GaN films grown at lower growth rates (∼16 A/min). Higher concentration of oxygen impurity was present in the GaN films grown at...

The present study describes a dual-stage electroplating method developed to construct numerous active nucleation sites on a target surface for the purpose of enhancing the pool boiling heat transfer performance. Electroplating with high current densities (0.17 ∼ 1.2 A/cm2) builds micro-scale copper dendrites and nodules on the base surface (oxygen free copper) and low current density electroplating (fixed, 0.05 A/cm2) follows to achieve the strong bonding strength of the micro-structures, which enable the coating to be robust in terms of corrosion and endurance. Pool boiling experiments show that the electroplated surfaces extend the boiling critical heat flux by 40∼70% for two working fluids tested and augment the boiling heat transfer coefficients by ∼700% and ∼600% in saturated R-123 and FC-72, respectively, at atmospheric pressure over a baseline (plain surface).Copyright © 2014 by ASME

STUDY DESIGN: Human annulus fibrosus (AF) cells were stimulated in vitro with interleukin (IL)-1β and exposed to biphasic electrical currents. OBJECTIVE: To identify the effect of biphasic electrical currents on the production of the extracellular matrix-modifying enzymes and inflammatory mediators in IL-1β-stimulated AF cells. SUMMARY OF BACKGROUND DATA: Symptomatic disc degeneration is an important cause of chronic intractable lumbar pain and is associated with macrophage-mediated inflammation in the AF. The inflammatory reaction relationship has not been studied in the AF. METHODS: Human AF cells were treated with 1 ng/mL IL-1β and cultured in a microcurrent generating chamber system. The levels of matrix metalloproteinase (MMP)-1, MMP-3, tissue inhibitor of metalloproteinase (TIMP)-1, TIMP-2, IL-6, IL-8, vascular endothelial growth factor (VEGF), insulin-like growth factor, and nitric oxide (NO) were measured. Expression of cyclooxygenase 2 and type I collagen mRNA was analyzed. RESULTS: Compared with unstimulated cells, IL-1β-stimulated AF cells produced significantly higher levels of MMP-1, MMP-3, IL-6, IL-8, NO, and VEGF, and lower levels of TIMP-1 and TIMP-2. Exposure to a 250-mV/mm field induced time-dependent increases in IL-6, NO, MMP-1, TIMP-1, VEGF, and insulin-like growth factor-1 production. The cells exposed to 500-mV/mm field produced significantly less MMP-1, TIMP-1, IL-6, and VEGF than unexposed cells (MMP-1, 17.2 ± 4.7 ng/mL vs. 27.3 ± 3.9 ng/mL, P< 0.05; TIMP-1, 12.4 ± 3.3 ng/mL vs. 22.3 ± 2.1 ng/mL, P< 0.02; IL-6, 2.5 ± 0.9 ng/mL vs. 6.39 ± 1.90 ng/mL, P< 0.05; and VEGF, 0.1 ± 0.04 ng/mL vs. 0.44 ± 0.15 ng/mL, P< 0.03). NO production was markedly increased at 500 mV/mm (P< 0.0001). CONCLUSION: We showed that exposure of IL-1β-stimulated AF cells to a 500 mV/mm inhibited MMP-1, IL-6, VEGF, and TIMP-1 production. The results suggest that biphasic electrical current stimulation may have efficacy in diminishing symptomatic disc degeneration. LEVEL OF EVIDENCE: N/A.

Strong near-infrared (NIR) electroluminescence (EL) at room temperature from neodymium (Nd)-doped gallium nitride (GaN) thin films is reported. The Nd-doped GaN films were grown by radio-frequency planar magnetron cosputtering of separate GaN and metallic Nd targets in a pure nitrogen ambient. X-ray diffraction data did not identify the presence of any secondary phases and revealed that the Nd-doped GaN films had a highly textured wurtzite crystal structure with the c-axis normal to the surface of the film. The EL devices were fabricated with a thin-film multilayered structure of Al∕Nd-doped GaN∕Al2O3–TiO2∕indium-tin oxide and tested at room temperate. Three distinct NIR EL emission peaks were observed from the devices at 905, 1082, and 1364nm, arising from the radiative relaxation of the F3∕24 excited-state energy level to the I9∕24, I11∕24, and I13∕24 levels of the Nd3+ ion, respectively. The threshold voltage for all the three emission peaks was ∼150V. The external power efficiency of the fabricated EL...

Enhancement of cathodoluminescence of manganese-activated zinc gallate (ZnGa2O4:Mn) thin-film phosphor by energetic particle bombardment is reported. The ZnGa2O4:Mn thin-film phosphor was grown at room temperature on silicon (100) substrates by rf magnetron sputter deposition from a 2 mol % Mn-doped ZnGa2O4 target in an oxygen–argon mixture. After the deposition, the films were annealed at 800 °C for 3 h in air. The influence of energetic particle bombardment on cathodoluminescent (CL) properties of ZnGa2O4:Mn films was investigated by varying a gas pressure during the sputter growth. Our results have shown that CL brightness from ZnGa2O4:Mn films grown at 2 mTorr was more than eight times higher than that of films grown at 20 mTorr. The remarkable improvement in CL brightness from ZnGa2O4:Mn films grown at a low pressure is presumably due to the energetic particle bombardment of the growing film surface yielding a densely packed microstructure and a better crystalline quality with a highly [110]-textured...

The phase transition in gallium nitride (GaN) thin films at room temperature from the thermodynamically stable wurtzite to the metastable zinc-blende structure is studied. The GaN films were grown at room temperature on (100)-oriented silicon substrates by radio-frequency planar magnetron sputtering of a GaN target in pure nitrogen atmosphere. As the nitrogen gas pressure during the film growth is decreased from 30 to 10 mTorr, the crystalline phase of GaN films changed from a hexagonal wurtzite to a cubic zinc-blende structure with (111) crystallographic planes oriented preferentially parallel to the film surface. The mechanisms responsible for the formation of the nonequilibrium cubic zinc-blende GaN phase at room temperature are suggested, in which the impact of the hyperthermal species impinging on the surface of growing films plays a key role in stabilizing the zinc-blende phase of GaN.

A demonstration of visible and near-infrared (NIR) alternating-current electroluminescence from sputter-grown GaN thin films doped with Er is reported. The alternating-current thin-film electroluminescent (ACTFEL) devices were constructed using a standard single-insulating structure, Al/GaN:Er/aluminum–titanium–oxide/indium–tin–oxide/Corning 7059 glass. Visible emissions peaked at 550 and 665 nm as well as NIR emissions centered at 1000 and 1550 nm were observed from the fabricated ACTFEL devices operating at room temperature. The visible and NIR emissions at 550, 665, 1000, and 1550 nm were attributed to the Er3+ 4f–4f intrashell transitions from the 4S3/2, 4F9/2, 4I11/2, and 4I13/2 excited-state levels to the 4I15/2 ground state, respectively. The green 550 nm emission had a larger dI/dV and a higher threshold voltage, Vth than the NIR 1550 nm emission, which could result from the need for higher electron impact energy to impact-excite the Er ion into the higher-energy excited-states for emission of green light.

Erbium doped gallium nitride (GaN) thin films were deposited on Si substrates by reactive rf magnetron cosputtering of a commercial GaN target, together with a metallic erbium target. Nitrogen was employed as the reactive sputtering gas. The gallium nitride doped erbium (GaN:Er) films thus obtained, exhibited the characteristic 525, 540, 660, and 1550 nm photoluminescence emission associated with the Er+3 ion 4f–4f intraband transitions. In addition, 1550 nm IR electroluminescence (EL) emission was observed from the sputter deposited GaN:Er phosphor films. The EL device was an inverted half-stack ac thin-film EL device structure. The 1550 nm EL emission is consistent with impact excitation and subsequent 4I13/2→4I15/2 radiative relaxation of Er+3 ions. Impact excitation requires conduction electrons with sufficient energy from electrical field acceleration, to excite the transition.

We report active-matrix organic polymer light-emitting displays (LEDs) based on a three hydrogenated amorphous silicon (a-Si:H) thin-film transistor (TFT) pixel electrode circuit that supplies a continuous output current to organic polymer light-emitting devices. The output current level drift induced by either process variations or device aging can be reduced in this design by adjusting the driver TFT operating point with the active resistor. Our first green light-emitting engineering prototype had a brightness of 120 cd/m/sup 2/ and fill factor of about 45%.

Study design We hypothesized that AF/neuron interactions during annular injury were involved in neovascularization and nerve ingrowth, the pathologic hallmarks of symptomatic disc degeneration. Objective To identify growth factors and inflammatory cytokines related to AF/neuron interactions using in vitro model. Summary of background data Discogenic pain is the chronic intractable pain initiated by tears in the outer annulus fibrosus (AF); this is a unique structure with free nerve endings at outer one-third, located beside dorsal root ganglia. The relationship between AF and neuron cells in annular injury has not been extensively investigated. Methods Human AF cells were cocultured with a retinoic acid (RA)-treated SH-SY5Y human neuroblastoma cell line (neuron-like cells). Conditioned media from cells cultured alone or in coculture were assayed for growth factors and inflammatory cytokines using enzyme-linked immunosorbent assays. The responses of the neuron-like cells, the AF cells, and the cocultured group to IL-1β/TNF-α were compared using the same outcome measures. Results RA-treated SH-SY5Y cells showed significant neurite outgrowth on the 7th day; this is a typical morphologic finding of neuron-like cells. Neuron-like cells produced vascular endothelial growth factor (VEGF) and IGF-1 under basal conditions and dose-dependently secreted small amounts of IL-8 in response to TNF-α. Coculturing enhanced the secretion of VEGF, TGF-β1, and β-NGF, and suppressed the production of IGF-1. VEGF in the coculture group and the AF cells was downregulated by IL-1β/TNF-α stimulation. IL-1β/TNF-α stimulation enhanced the production of large amounts of IL-6 and IL-8 from AF cells; IL-1β produced a greater response than TNF-α. The neuron-like cells did not produce detectable amounts of IL-6 or IL-8. Conclusion These studies suggest that AF cells are involved in an inflammatory reaction and that the interactions between AF and neuron-like cells enhance the production of growth factors responsible for neovascularization and nerve ingrowth. AF injury has the potential to initiate neovascularization/nerve ingrowth and an inflammatory reaction through the interactions of AF and neural tissues.

Transient recovery (TR) of evoked synaptic potentials and ATP depletion during the late stage of hypoxic hypoglycemic insults were investigated in rat hippocampal slices. TR was observed not only in the late stage of insult, but also during recovery. The concentration of ATP corresponded to the appearance (27% of control) and disappearance (15% of control) of TR. Paired pulse studies showed the presynaptic nature of the release of inhibition of synaptic transmission during TR. Both N- and P/Q-type voltage-dependent calcium channels were involved in the appearance of TR. This evidence suggests that underlying mechanisms of TR appearance during hypoxic hypoglycemic insult might be related to ATP depletion and release of A1 adenosine receptor mediated inhibition of presynaptic voltage-dependent calcium channels.

This investigation conducts pool boiling experiments under saturated conditions (Tsat = 60 °C) using nanofluids as the coolants. Three different nanofluids were tested including zinc oxide (ZnO)-water, aluminum oxide (Al2 O3 )-water and aluminum oxide (Al2 O3 )-water+ethylene glycol (ethylene glycol solution). At saturation (Tsat = 60°C), the pool boiling performance of the two pure water based nanofluids were similar. The maximum CHF enhancement as compared to the predicted Zuber’s [1] CHF evaluated at an equivalent saturation temperature is ∼180% for Al2 O3 -water nanofluids and ∼240% for ZnO-water nanofluids. In both cases, no degradation in the boiling heat transfer rate was observed for lower nanoparticle concentrations. However, higher nanoparticle concentrations demonstrate nucleate boiling heat transfer degradation at high heat fluxes. The dispersion of Al2 O3 nanoparticles in various ethylene glycol solutions is also found to enhance CHF by as much as ∼130%. A significant difference in the diameter of individual grains/particles (27 ± 16.3 nm) and the volume weighted average diameter of particles in solution (155 ± 80 nm) indicates that the Al2 O3 -water nanofluids consist primarily of nanoparticle agglomerates. Gravimetric fractionation of the nanofluid produced nanofluids with particle/particle aggregate average diameters that ranged from 69–346 nm. Over the size range tested, there was no significant CHF dependence on the average particle diameter.Copyright © 2005 by ASME

The expression of vascular endothelial growth factor (VEGF) and fibroblast growth factor (FGF)2 in the irradiated brain was examined to test how a single high dose radiation, similar to that used for intraoperative radiation therapy given to the normal cerebrum, can affect the vascular endothelium. After a burr hole trephination in the rat skull, the cerebral hemisphere was exposed to a single 10 Gy dose of gamma rays, and the radiation effect was assessed at 1, 2, 4, 6, and 8 weeks after irradiation. His-tological changes, such as reactive gliosis, inflammation, vascular proliferation and necrosis, were correlated with the duration after irradiation. Significant VEGF and FGF2 expression in the 2- and 8-week were detected by enzyme-linked immunosorbent assay quantification in the radiation group. Immunohistochemical study for VEGF was done and the number of positive cells gradually increased over time, compared with the sham operation group. In conclusion, the radiation injuries consisted of radiation necrosis associated with the expression of VEGF and FGF2. These findings indicate that VEGF and FGF2 may play a role in the radiation injuries after intraoperative single high-dose irradiation.

Simultaneous recordings of orthodromic PS, fEPSP and antidromic PS revealed EPSP/spike (E-S) dissociation, indicating a conversion of input/output relations from early and brief excitability to a late and prolonged depression during the recovery from depolarization induced by high levels of potassium. E-S potentiation was partially attenuated by pre-treating the slices with BAPTA-AM and lidocaine and totally eliminated by a submaximal concentration of muscimol. The time lag for recovery was decreased by the GABA(A) antagonist and completely eliminated by the A(1) antagonist. From these observations, we conclude that Ca(2+) dependent inhibitory suppression is the main cause of a brief period of E-S potentiation, and accumulation of adenosine is the mechanism responsible for prolonged depression of synaptic transmission

We have developed three hydrogenated amorphous silicon (a-Si:H) thin-film transistors (TFTs)-based pixel electrode circuits for active-matrix organic polymer light-emitting displays (AM-OP-LEDs). Our 3- a-Si:H TFTs voltage driven pixel electrode circuits can supply a continuous output current for AM-OP-LEDs. Each pixel circuit has compensation circuits that can adjust for the OP-LED and a-Si:H TFTs electrical characteristics shift. This pixel electrode circuit fabricated in our laboratory had the driving output current level of 1.13 (mu) A that is equivalent to a pixel current density of over 20 mA/cm2. The display brightness of ~4500 cd/m2 for green light (540 nm) can be achieved with this type of pixel electrode circuits for the organic polymer light-emitting devices having an external quantum efficiency of 5%.© (2002) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

Total excision is a treatment of choice in preventing the relapse of craniopharyngioma, but for tumors involving an extensive area, it is often associated with an increased risk of complications. We have performed a partial or subtotal tumor removal followed by repeated injection of bleomycin into the remaining tumor through a subcutaneous reservoir as postoperative adjuvant therapy. A retrospective review of clinical, radiological, and surgical data was performed for 10 patients (5 males and 5 females; age, 3-65 yr; follow-up duration, 12-79 months) with cystic craniopharyngiomas. The measurements of lactate dehydrogenase (LDH) level at each aspiration were performed. The shrinkage and/or stabilization of tumor was initially noted in all cases. The recurrence of tumor was seen in 4 cases (40%). The decreased or increased level of LDH was interpreted as tumor shrinkage or recurrence, respectively. The transient toxic reactions were observed in 3 patients (30%). Our study demonstrates that postoperative bleo-mycin injection for cystic craniopharyngioma, although does not appear to eradicate the tumor, decreases and stabilizes the tumor size, when used as an adjuvant therapy in young patients.

Aluminum metallization incorporating the anodic aluminum oxide has been optimized for high-performance amorphous silicon thin film transistors (a-Si:H TFTs). For such a device, the off-current is less than the picoampere and the ON-OFF current ratio is ∼2×107, the field effective mobility is about 1.25 cm /Vsec in the linear region and the subthreshold swing is about 0.38 V/decade. These electrical performances are acceptable for high-definition AMLCDs.

The influence of ion bombardment on the mechanical stress and microstructure of sputtered silicon nitride (SiNx) films has been systematically investigated. Applied substrate bias voltage was used to control the bombardment energy in a radio frequency (rf) reactive magnetron sputtering system. The resultant films were characterized by transmission electron microscopy (TEM), atomic force microscopy (AFM), Fourier transform infrared spectroscopy (FT-IR), Rutherford backscattering spectrometry (RBS), stress and chemical etch rate measurements. As the bias voltage was increased, the internal stress in SiNx films became increasingly compressive and reached a value of about 18.3 × 109 dyne/cm2 at higher bias voltages. These correlated well with the transition of the film microstructure from a porous microcolumnar structure containing large void to the more densely packed one. The obtained results can be explained in terms of atomic peening by energetic particles, leading to densification of the microstructure. It was also found that the amount of argon incorporated in the film is increased with increasing bias voltage, whereas the oxygen content is decreased. The lowest etch rate in buffered HF solution, approximately 1.2 Å/sec, was observed with the application of a substrate bias of -50 V.

As the oxide TFT-oriented simulator, the subgap density of states- based amorphous oxide TFT simulator (DAOTS) is proposed, implemented, and demonstrated for a-InGaZnO TFTs. It consists of the parameters having their physical meanings. Moreover, concrete techniques for parameter extraction are supplied. Most preferably, the quantitative self-consistency with experimental data is guaranteed in DAOTS.

We developed amorphous hafnium-indium-zinc oxide (HIZO) thin films as oxide semiconductors and investigated the films electrically and physically. Adding of hafnium (Hf) element can suppress growing the columnar structure and drastically decrease the carrier concentration and hall mobility in HIZO films. The thin film transistors (TFTs) with amorphous HIZO active channel exhibit good electrical properties with field effect mobility of around 10 cm2/Vs, S of 0.23 V/decade, and high Ion/off ratio of over 108, enough to operate the next electronic devices. In particular, under bias-temperature stress test, the HIZO TFTs with 0.3 mol % (Hf content) showed only 0.46 V shift in threshold voltage, compared with 3.25 V shift in HIZO TFT (0.1 mol %). The Hf ions may play a key role to improve the instability of TFTs due to high oxygen bonding ability. Therefore, the amorphous HIZO semiconductor will be a prominent candidate as an operation device for large area electronic applications.

Background and Objective:Oxygen-derived free radicals (OFRs), produced as myocardium is reperfused after ischemic injury, contribute to reversible and irreversible cellular injury. KATP channels, activated by ischemia, have been reported to participate in the arrhythmogenic response to acute myocardial ischemia. Therefore, we examined the effects of OFRs on the regulation of KATP channel activity. Materials and Methods: Isolated mice (ICR) hearts were perfused with Tyrode’s solution on a Langendorff apparatus. Single ventricular myocytes were isolated using enzymatic digestion with collagenase and protease. Single channel currents in the inside-out patch mode were recorded. OFRs were applied by mixing hypoxanthine and xanthine oxidase. The currents were recorded in the patch membrane at a holding potential of -60 mV. Results:OFRs generated by 0.1 U/mL xanthine oxidase and 0.5 mM hypoxanthine had no effects on the activities of KATP channels before and after treatment with 200 μM ATP. OFRs generated with 0.2 U/mL xanthine oxidase and 1.0 mM hypoxanthine reactivated the channel activities which had been attenuated by 100 μM ATP. In the presence of 100 U/mL superoxide dismutase and 122 U/mL catalase, which are OFRs scavengers, OFRs did not affect the KATP channels activities. Conclusion:OFRs generated by the reaction of hypoxanthine and xanthine oxidase increased the KATP channel activities in the inside-out patch. (Korean Circulation J 2003;33 (12):1140-1146)

In this paper, we describe hydrogenated amorphous silicon (a-Si:H) thin-film transistor (TFT)-based active-matrix arrays for active-matrix organic light-emitting displays (AM-OLEDs). The proposed pixel electrode circuits based on three a-Si:H TFTs can supply a continuous output current for AM-OLEDs. Each pixel circuit has compensation circuits that can adjust for the OLED and a-Si:H TFTs electrical characteristics shifts.

Summary Objectives Recent data have suggested that macrophages are involved in the pathogenesis of discogenic back pain and enhance the secretion of inflammatory mediators in co-cultured annulus fibrosus (AF) cells. The purpose of these studies is to determine the role of p38 mitogen-activated protein kinase (p38 MAPK) signaling in the interactions between macrophage and AF cells. Methods Human AF cells were co-cultured with phorbol myristate acetate-stimulated macrophage-like THP-1 cells with and without p38 MAPK inhibition. Conditioned media from co-cultured cells were assayed for interleukin (IL)-6, IL-8, prostaglandin E2 (PGE2), PGF2α, and vascular endothelial growth factor (VEGF). Naive and macrophage-exposed AF cell responses to 10ng/ml tumor necrosis factor-α (TNF-α) were compared using the same outcome measures. Results IL-6, IL-8, PGE2, PGF2α, and VEGF were secreted in greater quantities by cells maintained in co-culture compared to macrophages or AF cells cultured alone. SB202190 blunted IL-6, PGE2, and PGF2α production in a dose-dependent manner in co-culture. However, it did not suppress IL-8 and VEGF production. TNF-α-stimulated AF cell inflammatory mediators were up-regulated by macrophage exposure. SB202190 successfully suppressed IL-6, IL-8, PGE2, and PGF2α secretion in macrophage-exposed AF cells in response to TNF-α. Conclusions Annular injury can result in macrophage infiltration, and this can cause enhanced inflammatory mediator and VEGF production by AF cells. The p38 MAPK pathway signals are responsible for much of IL-6 and PG secretion from AF cells with macrophage-like cells, suggesting that blockade of this signal may serve as a therapeutic approach to discogenic pain.