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Objectives Spinal cord ischemia (SCI) is one of the major concerns of postoperative paraplegia during major vascular or aortic surgery. Since mitochondrial dysfunction develops at the early stage of SCI, this study tested the neuronal protective effect of transplantation of viable mitochondria to the ischemic cord in rats. Methods SCI was induced by crossclamping of thoracic aorta at T6 level for 25 minutes, followed by release of vascular clip to restore aortic blood flow in the anesthetized rats. Mitochondria (100 μg) were isolated from freshly harvested soleus muscle and delivered via the internal jugular vein before releasing of vascular clip. The motor function was assessed independently up to 7 days after reperfusion. Spinal cords were harvested and analyzed for molecular and histological changes. Results Whole-body in vivo images acquired by an in vivo imaging system confirmed the enhancement of MitoTracker fluorescence at the regions below crossclamping and in the ischemic cord. Compared with control vehicles, transplantation of mitochondria significantly improved the lower-limb locomotor function of rats subjected to cord ischemia up to 7 days after surgery. Mitochondrial transplantation suppressed the regional endoplasmic reticulum stress in the ischemic cord by attenuating CCAAT-enhancer-binding protein homologous protein expression and restoring binding immunoglobulin protein levels. In accordance, tissue levels of interleukin-6, tumor necrosis factor-α, and caspase-3 were attenuated in the mitochondrial transplanted group. Histologic examination also showed significant increase in numbers of Nissls bodies in the neurons at the ventral horn of ischemic cord following mitochondrial transplantation. Conclusions Our study showed that transplantation of freshly isolated mitochondria during the early stage of spinal cord ischemia–reperfusion injury suppressed the oxidative stress in endoplasmic reticulum of the injured cord, thereby reducing neuroapoptosis and improving locomotor function of rats with SCI.

Interferons (IFNs) are cytokines secreted by infected cells that can interfere with viral replication. Besides activating antiviral defenses, type I IFNs also exhibit diverse biological functions. IFN-β has been shown to have a protective effect against neurotoxic and inflammatory insults on neurons. Therefore, we aimed to investigate the possible role of IFN-β in reducing mechanical allodynia caused by Complete Freund’s Adjuvant (CFA) injection in rats. We assessed the antinociceptive effect of intrathecal IFN-β in naïve rats and the rats with CFA–induced inflammatory pain. After the behavioral test, the spinal cords of the rats were harvested for western blot and immunohistochemical double staining. We found that intrathecal administration of IFN-β in naïve rats can significantly increase the paw withdrawal threshold and paw withdrawal latency. Further, the intrathecal injection of a neutralizing IFN-β antibody can reduce the paw withdrawal threshold and paw withdrawal latency, suggesting that IFN-β is produced in the spinal cord in normal conditions and serves as a tonic inhibitor of pain. In addition, intrathecal injection of IFN-β at dosages from 1000 U to 10000 U demonstrates a significant transient dose-dependent inhibition of CFA-induced inflammatory pain. This analgesic effect is reversed by intrathecal naloxone, suggesting that IFN-β produces an analgesic effect through central opioid receptor-mediated signaling. Increased expression of phospho-µ-opioid receptors after IFN-β injection was observed on western blot, and immunohistochemical staining showed that µ-opioids co-localized with IFN-α/βR in the dorsal horn of the spinal cord. The findings of this study demonstrate that the analgesic effect of IFN-β is through µ-opioid receptors activation in spial cord.

Recent studies using microarray-based approaches have demonstrated that microRNAs (miRNAs) are involved in pain processing pathways. However, a significant proportion of computational predictions of miRNA targets are false-positive interactions. To increase the chance of identifying biologically relevant targets, we performed an integrated analysis of both miRNA and mRNA expression profiles in the rat spinal cord during complete Freund's adjuvant (CFA)-induced inflammatory pain. We generated miRNA and mRNA arrays from the same corresponding samples on days 5 and 14 after CFA injection. Five miRNAs and 1096 mRNAs in the CFA 5d group and 16 miRNAs and 647 mRNAs in the CFA 14d group were differentially expressed based on a filter of at least a 1.5-fold change in either direction. An integrated analysis revealed 54 mRNA targets with an inverse correlation to the expression patterns of three miRNAs in the CFA 5d group. Seventy-five targets were inversely correlated to six miRNAs in the CFA 14d group. The miRNA-mRNA interaction networks revealed significant changes in miR-124, miR-149, miR-3584 and their target genes, IL-6R, ADAM19, LAMC1 and CERS2, in the CFA 5d group. In the CFA 14d group, significant changes were noted in miR-124, miR-29, miR-34, miR-30, miR-338 and their target genes, TIMP2, CREB5 and EFNB1. We also investigated an interaction pair, miR-124-3p and IL-6R, and the results showed that miR-124-3p could attenuate inflammatory pain and decrease IL-6R expression in the spinal cord. These specific miRNAs and their target genes provide possible avenues for the diagnosis and treatment of inflammatory pain.

Background. Light-emitting diode (LED) phototherapy has been reported to relieve pain and enhance tissue repair through several mechanisms. However, the analgesic effect of LED on incised wounds has never been examined.Objectives. We examined the analgesic effect of LED therapy on incision pain and the changes in cyclooxygenase 2 (COX-2), prostaglandin E2 (PGE2), and the proinflammatory cytokines interleukin 6 (IL-6), IL-1β, and tumor necrosis factorα(TNF-α).Methods. Rats received LED therapy on incised skin 6 days before incision (L-I group) or 6 days after incision (I-L group) or from 3 days before incision to 3 days after incision (L-I-L group). Behavioral tests and analysis of skin tissue were performed after LED therapy.Results. LED therapy attenuated the decrease in thermal withdrawal latency in all the irradiated groups and the decrease in the mechanical withdrawal threshold in the L-I group only. The expression levels of COX-2, PGE2, and IL-6 were significantly decreased in the three LED-treated groups, whereas IL-1βand TNF-αwere significantly decreased only in the L-I group compared with their levels in the I groups (p<0.05).Conclusions. LED therapy provides an analgesic effect and modifies the expression of COX-2, PGE2, and proinflammatory cytokines in incised skin.

A three-dimensional simulation model is used to study the oxygen concentration distribution in silicon crystal during the Czochralski growth process under a transverse uniform magnetic field. The flow, temperature, and oxygen concentration distributions inside the furnace are calculated for different crystal lengths. There is significant variation in the flow structure in the melt with the growth length. The results show that in the initial stages, there is a decrease in the oxygen concentration at the crystal-melt interface as the length of the growing crystal increases. As the crystal lengthens further, a minimum value is reached after which the oxygen concentration increases continuously. This trend is consistent with that shown in the experimental results. The variation of the oxygen concentration with the growth length is strongly related to the depth of the melt in the crucible and the flow structure inside the melt. Better uniformity of the axial oxygen concentration can be achieved by proper adjustment of the crucible rotation rate during the growth process.

A numerical simulation has been performed to investigate the effect of a cusp magnetic field on the melt flow, thermal field and oxygen concentration during the Czochralski silicon crystal growth process. The results show a decrease in the oxygen concentration due to the reduction in size of the secondary flow cell that formed between the Taylor–Proudman vortex and the buoyancy-driven one. There is a significant reduction in the size of the secondary flow cell when the magnetic field is applied. As a consequence of the higher strength of the magnetic field there is a significant decrease in the oxygen concentration along the melt-crystal surface. The oxygen concentration is also very sensitive to the crucible rotation rate. There is an optimum crucible rotation rate for obtaining the lowest oxygen concentration. The oxygen concentration is lower for higher argon flow rate. The oxygen concentration decreases as the zero-Gauss plane (ZGP) moves from the free surface towards crucible bottom. When the ZGP is far from the free surface, the secondary flow cell appears and then the oxygen concentration increases. There is an optimum position of the ZGP to obtain the lowest the oxygen concentration.

A novel method to prepare the copper bonding on alumina substrate was presented. The cuprous Cu2O on the surface of Cu foil was prepared by covering cupric oxide (CuO) powder on Cu foil and treating at 600°C in N2 atmosphere. Then eutectic process was executed at 1075°C in N2 atmosphere to bond the Cu and alumina substrate. The cuprous grew on copper foil and bonding between Cu foil-alumina substrate were identified by XRD spectrum and SEM micrographs.

ZrN thin films were successfully deposited by DC magnetron sputtering on die steel substrates. The objective of this study was to investigate heat treatment on the microstructure, morphology, nanohardness properties determined by X-ray diffraction, field-emission scanning electron microscope (FE-SEM), nanoindentation, and pin-on-disk, respectively. The XRD result shows that ZrN has intensity of (111) and (200) peak after 400 °C for 1 h at lower nitrogen flow rates. The surface of coatings revealed smaller grains and smooth surface under heat treatment. ZrN coatings consisted of lower nitrogen flow rate had much lower friction coefficient, better mechanical properties by annealing treatment process.

ZrN films were prepared by magnetron sputtering on die steel substrates. The objective of this study was to investigate the effect of nitrogen flow rate on the microstructure ,morphology, nanohardness properties determined by X-ray diffraction, field-emission scanning electron microscope, nanoindentation, and pin-on-disk, respectively. The XRD shows that ZrN has (111) and (200) preferred orientation under lower nitrogen flow rates. The surface of coatings revealed smaller grains and uniform dense under lower nitrogen flow rates. With increasing the nitrogen flow rates, this result showed ZrN films lead to poor mechanical properties and hardness values. However, films consisted of up high ernitrogen flow rate had much lower friction coefficient.

Vanadium oxide films were deposited on ITO (Indium Tin oxide) glass substrates at room temperature byreactive DC magnetron sputtering.The Vanadium oxide films were varied the nitrogen flow rateto investigate composition, microstructure, optical properties, and electrochromic properties determined by X-ray diffraction, field-emission scanning electron microscope (FE-SEM), UV-visible spectrometer, andcyclic voltammetry. Experimental results indicatedthat V2O5filmsreactively sputtered at oxygen flow rates of 15 sccm had better electrochromic property and optimalperformance.

The NMDA receptor plays an important role in induction of pain hyperalgesia and allodynia by tissue trauma. Although the analgesic effect of NMDA receptor antagonists has been well reported in various experimental study and clinical pain trial, serious side effects were reported and limited their use in clinical medication. To obtain NMDA receptor antagonist with less side effects, an alternative approach is to use subtype-selective NMDA receptor antagonists. However, the effects of current available NMDA receptor antagonist’s drug are not absolute specific for antagonizing specific NMDA receptor subtypes.

It is well known that interferons (IFNs), such as type-I IFN (IFN-α) and type-II IFN (IFN-γ) are produced by immune cells to elicit antiviral effects. IFNs are also produced by glial cells in the CNS to regulate brain functions. As a proinflammatory cytokine, IFN-γ drives neuropathic pain by inducing microglial activation in the spinal cord. However, little is known about the role of IFN-α in regulating pain sensitivity and synaptic transmission. Strikingly, we found that IFN-α/β receptor (type-I IFN receptor) was expressed by primary afferent terminals in the superficial dorsal horn that co-expressed the neuropeptide CGRP. In the spinal cord IFN-α was primarily expressed by astrocytes. Perfusion of spinal cord slices with IFN-α suppressed excitatory synaptic transmission by reducing the frequency of spontaneous excitatory postsynaptic current (sEPSCs). IFN-α also inhibited nociceptive transmission by reducing capsaicin-induced internalization of NK-1 and phosphorylation of extracellular signal-regulated kinase (ERK) in superficial dorsal horn neurons. Finally, spinal (intrathecal) administration of IFN-α reduced inflammatory pain and increased pain threshold in naïve rats, whereas removal of endogenous IFN-α by a neutralizing antibody induced hyperalgesia. Our findings suggest a new form of neuronal-glial interaction by which IFN-α, produced by astrocytes, inhibits nociceptive transmission in the spinal cord.

Vanadium oxide films were deposited on ITO (Indium Tin oxide) glass substrates at room temperature by reactive DC magnetron sputtering. The effect of annealing temperature on composition, microstructure, optical properties, and electrochromic properties of vanadium oxide films were investigated by X-ray diffraction, field-emission scanning electron microscope (FE-SEM), UV-visible spectrometer, and cyclic voltammetry. These films showed (110) crystalline orientation after annealing at 300 °C. V2O5 films with more porosity had better electrochromic property and optimal performance after heat treatments.

Electrochromism have been widely investigated due to their potential applications such as automobile and building window. In this study, tantalum oxide thin films used as ion conducting layer were deposited on WO3/ITO at room temperature by magnetron sputtering. The thickness of tantalum oxide films were varied to investigate their effects on composition, microstructure, optical properties, and electrochromic properties determined by X-ray diffraction, UV-visible spectrometer, Atomic force microscope (AFM), and field-emission scanning electron microscope (FE-SEM). Experimental results indicated Ta2O5at thickness of 300 nm with low packing density were favorable for ions transmission deposited on WO3/ITO had better electrochromic property.

Multilayers of CrN/Si3N4 coatings were prepared by magnetron sputtering on die steel substrates. The layers of CrN/Si3N4 films were varied to investigate their effects on microstructure, morphology, nano-hardness properties determined by X-ray diffraction, field-emission scanning electron microscope (FE-SEM), nanoindentation, and pin-on-disk, respectively. The result shows that CrN has highly (111) preferred orientation and Si3N4 exhibits amorphous phase at working temperature of 200 oC. The surface of coatings revealed smaller grains and uniform dense with higher layers. The number of layers increased with enhancing of the mechanical properties, and hardness values. At 64 layers films had the largest nano-hardness. Besides, the highest layers of CrN/Si3N4 multilayers have been achieved the lowest friction coefficient for against steel ball.

Objective Premature infants are more prone to cardiorespiratory complications after surgery than term infants. Risk factors for postoperative apnea include post-conception age, gestational age, postnatal age, birth weight, history of respiratory distress syndrome, bronchopulmonary dysplasia, anemia, necrotizing enterocolitis, use of opioids or nondepolarizing muscle relaxants, aminophylline use, history of apnea, body weight at operation, and pre-existing disease. The aim of this study was to identify the most important factors associated with postoperative extubation and respiratory outcomes among premature infants undergoing cryotherapy for retinopathy of prematurity (ROP). Methods We retrospectively analyzed the clinical records of 62 premature infants, with mean ± standard deviation gestational age of 26.4 ± 2.3 weeks, birth weight of 914.8 ± 208.5 g, postconception age of 37.0 ± 2.8 weeks, and body weight at the time of operation of 1970.0 ± 446.8 g, who underwent cryotherapy for ROP. Results Only 17 infants were successfully extubated within 2 hours after operation. The most predictive factor for successful or unsuccessful extubation was body weight at the time of operation. Conclusion Body weight at the time of operation was the most important factor associated with postoperative ventilatory support among premature infants under-going cryotherapy for ROP.

We hypothesized that optimal laryngeal mask airway (LMA) insertion conditions might be achieved with topical lidocaine and a smaller dose of propofol. In this study, insertion conditions after topical lidocaine 40 mg followed by propofol 2 mg.kg(-1) were compared with propofol 2 mg.kg(-1) or propofol 3 mg.kg(-1) alone.Ninety patients were recruited for this randomized prospective double-blind study. One group received four sprays of topical lidocaine (40 mg) over the posterior pharyngeal wall followed by propofol 2 mg.kg(-1) (Group 2PL; n = 30). The other two groups received four sprays of 0.9% normal saline followed by propofol 2 mg.kg(-1) (Group 2P; n = 30) or by propofol 3 mg.kg(-1) (Group 3P; n = 30). The frequency of optimal insertion conditions (successful insertion at the first attempt without adverse responses) and side effects were recorded.The frequency of optimal insertion conditions was greater in Group 2PL (20/30, 67%) and Group 3P (22/30, 73%) than in Group 2P (11/20, 37%) (P = 0.009). In Group 3P, the mean blood pressure was lower than in the other groups prior to LMA-Classic insertion (P = 0.003) but was similar after insertion. The incidence of apnea was greater in Group 3P patients (17/30, 57%) than in Group 2P (2/30, 7%) or Group 2PL patients (1/30, 3%) (P0.001).Topical lidocaine 40 mg followed by propofol 2 mg.kg(-1) can provide optimal insertion conditions of the LMA-Classic comparable to those of propofol 3 mg.kg(-1), with fewer hemodynamic changes and a lower incidence of apnea.

High-current level ZnO thin-film transistors (TFTs) on transparent substrates are demonstrated using low-temperature RF sputtering. Oxygen passivation induced fill of oxygen vacancies within the sputtered n-type ZnO thin films on glass substrates is investigated to manipulate the performance of top-gate ZnO TFTs. The surface oxygen passivation effectively enlarges grain size of the ZnO on glass substrates from 7 nm to 20 nm and increases the oxygen composition ratio from 30% to 35%, which essentially yields a TFT with its significantly increase of drain-source current and Ion/Ioff ratio, as compared with a typical ZnO based TFT. The optimum duration of oxygen passivation in this study yields a device with a drain-source current level 0.87 mA under a bias condition VGS = 5 V and VDS = 15 V, Ion/Ioff ratio 1.4 times 106. We further demonstrate high-performance top-gate ZnO TFTs by applying similar low-temperature process on a flexible polymer substrate. The device shows an IDS 26 muA under a bias condition VGS = 15 V and VDS = 25 V with gate size W/L = 600 mum/300 mum. The average optical transmission of the entire flexible TFT structure in the visible spectrum range is about 82% while the transmission at 550 nm is 88%.

Long-time evolution of the electrical characteristics for two-terminal and transistor of poly(3-hexylthiophene) film with various gate dielectric interfaces are measured. The oxygen doping is found to depend sensitively on the amount of hydroxyl groups of the interface and irreversible after long time in vacuum except for quartz. For a given interface, dip-coated film always has a higher doping level and slower de-doping than spin-coated films because of higher porosity. With careful control of the oxygen level transistor with mobility of 0.12 cm 2 /V s and on–off ratio of 29,000 are obtained for dip-coated film on glass substrate.

In this paper, we successfully fabricate polycrystalline silicon films with very large and uniform-size grains by the method of nanometer thick aluminum induced crystallization (nano-AIC) on the a-Si:H film deposited by plasma enhanced chemical vapor deposition (PECVD). The effect of annealing ramp-up time is discussed. Four different annealing ramp-up time, 1,5,10,20 hours, are tested. The results show the maximum average grain size obtained in this paper is about 60 μm under the condition of 20-hour annealing ramp-up time. The nano-AIC specimens show a much better leakage current characteristics than the AIC specimens since the Al layer in AIC process is much thicker and was not removed completely from the polycrystalline silicon film during Al wet selective etching process.

ZnO-based thin film transistors (TFTs) fabricated on both glass and flexible substrates are investigated. The ZnO thin film mentioned in this entire work is deposited by RF magnetron sputtering with the presence of O2 at low deposition rate and low temperature. For TFT on glass, the IDS is as high as 1 mA when biased at the saturation region VDS = 10-20 V and VGS = 5 V without any post thermal anneal. The Ion/Ioff ratio is . We believe the results are among the best ZnO TFTs ever obtained. For TFT on plastic, all the patterns are defined by standard photolithography. The IDS - VDS and IDS - VGS curves along with optical transmission of the whole structure are presented in this paper.

The effects of TiN addition to Si3N4 on its mechanical and wear properties were investigated. The size and content of TiN particles were found having effects on the strength and toughness of Si3N4-based composites. The friction and wear behavior of Si3N4 based composites against AISI-52100 steel were investigated in the ball -on- disc mode in a non-lubrication reciprocation motion. It has been found that under the conditions used all the ceramic components exhibited rather low friction and wear coefficients. For monolithic silicon nitride materials, high friction coefficients between 0.6 and 0.7 and wear coefficients between 1.63 × 10-8 and 1.389 × 10-6 mm3/N.m were measured. The contact load was varied from 100 to 300 N. By adding titanium nitride, the friction coefficients was reduced to a value between 0.4 and 0.5 and wear coefficients between 1.09×10-8 and 0.32×10-6 mm3/N.m at room temperature.

Thermal residual stress analysis and failure simulation of particle-reinforced composites are performed based on thermomechanics and the finite element method (FEM) to investigate the effects of particles on strength and toughness. It is discovered that the residual stresses in matrix are controlled mainly by adjacent particles via stress superposition, and an expression for the residual stress is derived. The size of the residual stress zone in the matrix is found to increase with the particle size. The FEM failure simulation in uniaxial tension reveals two features: (i) the residual stress caused by the second phase particles in ceramic matrix would lead to strength degradation due to the weakest link theory; (ii) the second phase particles in the composite may enhance the fracture toughness because of the crack arrest and crack-deflection caused by residual compressive stress. These features have been confirmed by experimental results of TiN/Si3N4 composite.

Background: Animal and human studies indicate that genetics may contribute to the variability of morphine efficacy. A recent report suggested that cancer patients homozygous for the 118G allele caused by the single nucleotide polymorphism at nucleotide position 118 in the -opioid receptor gene require higher doses of morphine to relieve pain. The purpose of the current study was to investigate whether this polymorphism contributes to the variability of morphine efficacy in women who undergo abdominal total hysterectomy. Methods: After informed consent was obtained, 80 female patients (American Society of Anesthesiologist physical status I or II) scheduled to undergo elective total hysterectomy surgery were enrolled in this study. All patients received general anesthesia and were screened for A118G polymorphism by blood sample. Intravenous morphine patient-controlled analgesia was provided postoperatively for satisfactory analgesia. The authors recorded the morphine consumption doses and demand times. Pain at rest and side effects were measured with rating scales. Results: Forty-three women were A118 homozygous, 19 were heterozygous, and 18 were G118 homozygous. Patients homozygous for G118 required more morphine doses (33 10 mg) to achieve adequate pain relief compared with patients homozygous for A118 (27 10 mg) in the first 24 h (P 0.02). However, there was no statistically significant difference for morphine consumption at 48 h. Conclusion: Genetic variation of the -opioid receptor may contribute to interindividual differences in postoperative morphine consumption. In the future, identifying single nucleotide polymorphisms of patients may provide information to modulate the analgesic dosage of opioid for better pain control. IT has been known for a long time that the effects of morphine as an agent for pain control vary in different individuals. Morphine produces its clinical effects mainly through -opioid receptors. Polymorphisms in the -opioid receptor gene may be associated with the clinical effects of opioid analgesics, 1–3 which encourages research into human genetic polymorphisms and their clinical consequences. Several single nucleotide polymorphisms (SNPs) have been identified in the human -opioid receptor gene. The A118G mutation is the most common one leading to a change in the gene product in the human -opioid receptors, which is an A to G substitution in exon 1 and results in an amino acid exchange at position 40 from asparagine to aspartate (N40D). 4 Functional effects of the A118G polymorphism have been demonstrated both in vitro and in vivo. In vitro, -endorphin has been shown to bind three times more tightly at the receptor of homozygous G allele than at that of homozygous A allele. 4 A recent report also suggested that cancer patients who were homozygous for the G118 variant required higher doses of oral morphine for long-term treatment of their pain. 2 Romberg et al. 5,6 studied the pharmacokinetics and pharmacodynamics of morphine-6-glucuronide (M6G), a -opioid agonist, and also found that A118G mutation of the human -opioid receptor gene reduced analgesic responses to M6G. The effect of -opioid receptor genotype on acute postoperative morphine requirements has not been reported; therefore, we decided to determine morphine consumption with intravenous patient-controlled analgesia in women undergoing total abdominal hysterectomy according to A118G polymorphism.

Background: Epidural anesthesia is widely used in the obstetric setting for providing not only labor pain relief, but also surgical analgesia for cesarean section and postoperative pain relief. However, the side effect of pruritus is of great concern for its high occurrence rate. The aim of our study was to compare and analyze the effectiveness of different regimens of epidural morphine analgesia for postcesarean section patients experiencing pruritus. Methods: We had retrospectively studied from June 2003 to April 2004 144 subjects undergoing cesarean section who agreed to accept postoperative pain relief via epidural route. Visual analogue scales (VAS) were compared between subjects not experiencing pruritus (Group I) and subjects experiencing pruritus (Group II) with modified regimens. Results: Thirty six subjects (Group II) out of 144 patients (25%) suffered from pruritus. Six different regimens were prescribed by anesthesiologists in these subjects. The characteristic of most different regim...

Conductive TiN/Si3N4 ceramic composites were processed by electrical discharge machining (EDM) and their microstructure and conductivity investigated. A low electrical resistivity of 1.25×10-3Ω.cm was obtained in 40vol%TiN/Si3N4 composite. The whole process of tool electrode wear is evaluated by sinker-EDM. The machined surfaces of TiN/Si3N4 ceramic composites were examined by scanning electron microscopy (SEM) and profilometry to determine the surface finish. Micropores of 700µm in depth and 70µm in diameter were successfully machined in TiN/ Si3N4 composites by the micro-EDM method.

A sintered Si 3 N 4 matrix has been characterized by TEM. The film thickness distribution of Si 3 N 4 was measured by high resolution transmission electron microscopy (HREM). Surface grinding is performed on two table speeds of 0.08 and 0.25 m s −1 with different depth of cut. The ground surfaces were observed with scanning electron microscopy (SEM). The surface texture was found to have greater dependence on depth of cut and table speed. The surface roughness is improved after smaller depth of cut. The flexural strength of ground specimens were measured by four-point flexure tests. The effect of depth of cut during grinding on the flexural strength and reliability of silicon nitride is investigated. The large depth of cut of 30 μm/pass resulted in a further decreased in strength of 540 MPa and a Weibull modulus of 7.5. When the depth of cut of 5 μm/pass were subjected to the ground specimens, the average strength was increased to 670 MPa and Weibull modulus to 9.1.

The friction and wear behavior of Si3N4-based composites against AISI-52100 steel were investigated in the ball-on-disk mode in a nonlubrication reciprocation motion. It has been found that under the conditions used, all the ceramic components exhibited rather low friction and wear coefficients. For monolithic silicon nitride materials, high friction coefficients between 0.6 and 0.7 and wear coefficients between 1.63 × 10−8 and 1.389 × 10−6 mm3/N · m were measured. The contact load was varied from 100 to 300 N. By adding titanium nitride, the friction coefficients were reduced to a value between 0.4 and 0.5 and wear coefficients between 1.09 × 10−8 and 0.32 × 10−6 mm3/ N · m at room temperature. All materials and worn surfaces as well as wear debris were investigated by means of scanning electron microscopy, energy dispersive spectroscopy, x-ray diffraction, and transmission electron microscopy (TEM) before or after the tribological tests. The TEM micrographs of wear track revealed plastic deformation through twins and cracking along grain boundary which play an important role in the fracture mechanism.

Conductive TiN/Si3N4 ceramic composites were processed by electrical discharge machining (EDM) and their microstructure and conductivity were investigated. The whole process of tool electrode wear is evaluated by sinker-EDM. The machined surfaces of TiN/Si3N4 ceramic composites were examined by scanning electron microscopy (SEM) and profilometry to determine the surface finish. The electrode wear rate of brass is higher than copper electrode for all EDMed tests. The surface texture was found to have greater dependence on pulse energy. It was observed that the sinker-EDM at higher pulse energy caused severe microdamage in the surface. The surface roughness (Ra) values also increase with increasing pulse energy.

The starting α-Si 3 N 4 powders with or without the addition of β-phase seeds using Y 2 O 3 and Al 2 O 3 as sintering aids were gas-pressure-sintered with the conditions, 0.9 MPa nitrogen gas at 1850 °C for 1 h. The microscopic evidence indicates that β-Si 3 N 4 seeds incorporated in the starting α-Si 3 N 4 powders play an important role in microstructural development and mechanical properties for silicon nitride. The growth of β-Si 3 N 4 grains is initiated from the seeds, resulting in a core/shell microstructure was observed in the abnormal grain growth. As a result, the fracture toughness of silicon nitride was improved from 5.5 to 7.6 MPa m 1/2 by adding β-phase seeds.

Conductive TiN/Si3N4 hot pressed composites were processed by electrical discharge machining (EDM) and their microstructure and conductivity investigated. The dependence of surface texture, surface roughness, and materials removal rate on electrical discharge machining conditions including working voltage and feed rate were also analyzed. The flexural strength and strength reliability in terms of Weibull modulus of TiN/ Si3N4 processed by EDM and conventional cutting and polishing are compared. Higher working voltage and current, as well as higher content of TiN result in greater material removal rate. Comparison of the flexural strength and Weibull modulus of the composites processed by EDM with conventional polished samples revealed that the surface with low roughness lead to an increase in strength and reliability for electrical discharge machining.

In this study, multilayers of TiN/NbN were deposited by d.c. magnetron sputtering on die steel substrates. The structure, morphology and nano-hardness were assessed using X-ray diffraction, atomic force microscopy (AFM), stylus profiler (XP-2 stylus profiler) and nanoindentation, respectively. Wear tests were performed on pin-on-disk configuration and dry sliding conditions, at 5N load by using hardened steel ball. The result shows TiN with highly (111) preferred orientation. On mechanical properties, Young’s modulus and hardness values increase for layers number increase. At 64 layers films had the highest nano-hardness, Young’s modulus values. The TiN/NbN multilayer films presented changes in its morphology becoming more granulated and density after heating up to 500°C. A significant decrease in friction coefficient has been achieved for TiN/NbN multilayers against steel ball.

Particulate ceramic composites composed of Si 3 N 4 matrix and dispersing MoSi 2 particles were sintered in 1 MPa N 2 atmosphere at 1850°C for 1 h. The physical and mechanical properties of these composites containing 10, 20, 30, 40 and 50 vol% MoSi 2 were evaluated. The microstructure, strength, fracture toughness and electrical resistivity for the composite of MoSi 2 /Si 3 N 4 were investigated. The electrical resistivity of the composites decreases with increasing amount of dispersoids and reaches a minimum (∼10 -2 Ω.cm) in the 50 vol% MoSi 2 /Si 3 N 4 composite. Such a conductivity could be machined by wire electric discharge machining (WEDM). The removal rate of MoSi 2 /Si 3 N 4 composite was found to be dependent on electrical conductivity for constant working voltage. This result demonstrated the feasibility of machining structural ceramics using EDM method through the incorporation of MoSi 2 conductive phase into ceramic matrix composite.

TiN/NbN multilayers on steel substrates (SKD11) are produced using DC magnetron sputtering process. The multilayer obtained are characterized in composition by means of X-ray diffraction techniques, Microhardness and adhesion to the substrate were studied by atomic force microscopy and scratch tests. The morphological analysis and coating structure are studied using scanning electron microscopy, and atomic force microscopy. The film thickness is measured by a stylus profiler (XP-2 stylus profiler). Wear tests were performed on pin-on-disk configuration and dry sliding conditions, at 5N load by using hardened steel ball. On mechanical properties, higher Young’s modulus and hardness values follow to increase the TiN/NbN layers number. The multilayer films of 64 layers at 500°C 1h annealing indicated that the microhardness and Young’s modulus had the highest values.

Electrolytic nickel powder and water-atomized Fe36Ni alloy powder were consolidated into combined compacts with the “two-layer pressing” technique. The compacts, 1.6 mm thick, were sintered at 1200 and 1300‡C in hydrogen, and then rolled into strips 0.8 mm thick. The rolled and annealed strips were fixed at one end as a cantilever beam,and heated gradually from room temperature to 200‡C, in order to measure the thermal deflection of the free end. The measured displacement was always less than the theoretically calculated value, due to the existence of pores in the sintered products. The effect of the temperature and time of sintering on the thermal deflection of the bimetal strips was investigated. It was found that the proper degree of sintering is essential for the bimetal strip to exhibit the largest displacement upon heating. The microstructure and chemical composition across the nickel layer, the contact interface, and the Fe36Ni layer were examined with a SEM and EPMA.

MicroRNAs (miRNAs) are small noncoding RNA molecules of 18-25 nucleotides in length that regulate gene expression involved in fundamental cell processes. The induction and chronification of pain is associated with many expressional changes in pain-related proteins. miRNA has the potential to regulate gene and protein expression associated with the induction and chronification of pain. Thus, miRNAs might have promise in therapy and as a diagnostic and prognostic biomarker in pain medicine. The application of miRNA has been an emerging field in pain research in recent years. Many studies focusing on the regulation of miRNAs under different tissue and nociceptive stimuli have been performed in recent years. In this review, we intend to introduce the most recent research in the field of miRNA related with pain medicine such as the expression and function of miRNA in different animal pain model, the challenge of application and delivery of miRNA in vivo, the potential toxic effects of miRNA and future problems in clinical application that need to be resolved. This review focuses on the results of miRNA in animal studies and the prospect for future success.

Background and Purpose RNA polymerase II promoters that drive the expression of rationally designed primary microRNA-based shRNA, for example, shRNAmir, can produce more potent gene knockdown than RNA polymerase III promoters. Antagonists of peripheral N methyl-D-aspartate (NMDA) receptors that do not interfere with central glutamate processing would prevent the development of adverse central nervous system effects. Thus, in this study, we examined the effects of gene silencing and antinociception on formalin- and Complete Freund's adjuvant (CFA)-induced pain in rats by subcutaneously injecting a lentiviral vector encoding a shRNAmir that targets the NR1 subunit of the NMDA receptor. Methods Rats received intradermal injections of different doses of NR1 shRNAmir at different time points before injection of formalin. Pain behavior was assessed by monitoring the paw flinch response, paw withdrawal threshold, and thermal withdrawal latency. We then analyzed NR1 messenger RNA and protein expression in skin and the L5 dorsal root ganglion (DRG). Results We found that intradermal injection of 1, 5, and 10 μg of shRNAmir significantly inhibited flinch responses (p