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Functional nanocomposites have been widely studied in recent years. Because of its non-toxic and inexpensive properties, titanium dioxide has pervasive application value in the chemical industry. Nano-sized antimony-doped tin oxide (ATO) metallic oxide was developed and combined with a pure titanium dioxide substrate by the effective co-precipitation method. The obtained powder had good conductibility, and its carriers were supplied by the infiltrated Sb atoms in tin oxide crystal. In the present work, the calcination temperatures and molar ratio of tin (IV) chloride pentahydrate (SnCl4·5H2O) and antimony (III) chloride (SbCl3) were optimized for achieving excellent electrical performances. As a result, the sheet resistivity of Sb-SnO2/TiO2 was in the range from 9 kΩ·cm to 15 kΩ·cm. By mixing method, the resistance of Sb-SnO2/TiO2/PDMS could be as low as 2 MΩ.

Pure SiO2 aerogel has a strong light transmittance in the infrared wavebands from 3.0 to 8.0 μm, and an opacifier could efficiently reduce aerogel's radiative thermal conductivity (λr), especially at high temperatures (>400 K). Consequently, the λr of different core/shell structured opacifiers is proposed, including micron hollow sphere opacifier (MHSOP), i.e., hollow carbon black/SiC/TiO2, and phase change material (PCM)/opacifier, i.e., VO2/SiO2, and Ge2Sb2Te5/SiC; further, their conductive λ model has also been established. The results showed that MHSOP could reduce MHSOPs-SiO2 aerogel composite's λ compared to traditional solid structure opacifiers; the effect of MHSOPs with a certain core–shell ratio on suppressing thermal radiation is equivalent to their solid structure opacifier at high-temperature. Adding SiC MHSOPs reduces aerogel composites' weight and thermal conductivity by 42.19 and 26.29%, while the shading effect of a core–shell ratio of over 0.75 is equivalent to the solid structure. Specifically, rutile-phased VO2/SiO2's λr is smaller than TiO2 MHOSP, and crystalline Ge2Sb2Te5/SiC doped aerogel exhibits good thermal insulation. The proposed micron hollow sphere opacifier and PCM/opacifier provide a novelty, lightweight, and high-efficiency method to restrain aerogel's infrared radiation and improve insulation performance at high temperatures.

BackgroundAcute kidney injury (AKI) is a common complication after thoracoscopic lobectomy in high-risk patients due to insufficient intraoperative infusion. Goal-directed fluid therapy (GDFT) is an individualized fluid infusion strategy; the fluid infusion strategy is adjusted according to the patient’s fluid response. GDFT during operation can reduce the incidence of AKI after major surgery. Enhanced recovery after surgery (ERAS) protocol optimizes perioperative interventions to decrease the postoperative complications after surgery. In ERAS protocol of lobectomy, intraoperative restrictive fluid therapy is recommended. In this study, we will compare the effects of intraoperative GDFT with restrictive fluid therapy combined with an ERAS protocol on the incidence of AKI after thoracoscopic lobectomy in high-risk patients.Methods/designThis is a prospective single-center single-blind randomized controlled trial. Two hundred seventy-six patients scheduled for thoracoscopic lobectomy are randomly allocated to receive either GDFT or restrictive fluid therapy combined with an ERAS protocol at a 1:1 ratio. The primary outcome is the incidence of AKI after operation. The secondary outcomes include (1) the incidence of renal replacement therapy, (2) the length of intensive care unit stay after operation, (3) the length of hospital stay after operation, and (4) the incidence of other complications including infection, acute lung injury, pneumonia, arrhythmia, heart failure, myocardial injury after noncardiac surgery, and cardiac infarction.DiscussionThis is the first study to compare intraoperative GDFT with restrictive fluid therapy combined with an ERAS protocol on the incidence of AKI after thoracoscopic lobectomy in high-risk patients. The hypothesis is that the restrictive fluid therapy is noninferior to GDFT in reducing the incidence of AKI, but restrictive fluid therapy is simpler to apply than GDFT.Trial registrationClinicalTrials.govNCT04302467. Registered on 26 February 2020

Background The goal of this study was to review relevant randomized controlled trials in order to determine the efficacy of continuous positive airway pressure (CPAP) versus mandibular advancement device (MAD) in the treatment of obstructive sleep apnea (OSA). Methods Using appropriate keywords, we identified relevant studies using PubMed, the Cochrane Library, and Embase. Key pertinent sources in the literature were also reviewed, and all articles published through October 2019 were considered for inclusion. For each study, we used odds ratios (ORs), mean difference (MD), and 95% confidence interval (95% CI) to assess and synthesize outcomes. Results We included 14 RCTs, for a total of 249 patients in the CPAP group and 247 in the MAD group. Compared with MAD, CPAP significantly decreased apnea hypopnea index (AHI) (WMD: −7.08, 95%CI: −9.06∼-5.10) and the percentage of stage 1 and 2 after therapy (WMD: −3.728, 95%CI: −6.912∼-0.543). However, compared with MAD, CPAP significantly decreased the SF-36-social function score (WMD: −3.381, 95%CI: −6.607∼-0.154).There was no significant difference in Epworth sleepiness scale score after therapy between the two groups. Conclusion CPAP has better therapeutic efficacy in OSA patients than MAD.

OBJECTIVE The purpose of this study was to assess the fibrinolytic status after cardiopulmonary bypass in rheumatic valvular heart disease patients, and detect the associated factors of post-cardiopulmonary bypass hyperfibrinolysis. METHODS According to the fibrinolytic status after cardiopulmonary bypass, 203 rheumatic valvular heart disease patients were divided into two groups: hyperfibrinolysis group (H group, n = 78) and non-hyperfibrinolysis group (NH group, n = 125). The demographic characteristics, operative variables, and postoperative follow-ups were compared between these two groups. RESULTS The incidence of hyperfibrinolysis was 38.4% after cardiopulmonary bypass. Patients in the H group had a significant higher incidence of preoperative atrial fibrillation than patients in the NH group (92.3% vs. 55.2%, P

Carbon fiber reinforced polymer (CFRP) laminates have been widely employed in the manufacturing of airplane. Usually, hole-making is the final machining process to join CFRP laminates with other components. However, CFRP laminates are considered as hard-to-machine materials, which results in some serious failures during hole-making process such as fiber pull-out, fiber break, and matrix delamination. To improve the hole-making quality, a tilted orbital grinding (TOG) method was proposed in this study. In the proposed TOG method, a grinding wheel was used as the machining tool and its axis was set as tilted against the axis of the hole with a small angle. Through replacing the revolving motion of the tool in conventional helical milling with conical pendulum motion of the grinding wheel, a hole could be made by a grinding process. The thrust forces, cutting temperatures, and the quality of the holes in the proposed TOG process were investigated by experimental methods. The results show that the thrust forces and cutting temperatures in TOG process are greatly less than those in the conventional orbital milling process. Scanning electron microscope (SEM) images of the hole that made by TOG method show that there is no crack generated in the entrance side of the hole, and the pull-out delamination in the exit side of the hole is significantly reduced. The experimental results indicate that the proposed TOG method has a potential application in the hole-making of CFRP laminates.

This study aimed to elucidate the effect of miR-1306–3p on metastasis of hepatocellular carcinoma (HCC) and potential mechanism involved. miR-1306–3p promoted migration and invasion of HCC in vivo and in vitro. Moreover, miR-1306–3p inhibited snail to enhance its expression via directly targeting FBXL5, thus inducing the epithelial-mesenchymal transition (EMT) in HCC. Intriguingly, miR-1306–3p expression was transcriptionally enhanced by FoxM1. Consistently, miR-1306–3p was upregulated in HCC compared with paracarcinoma and correlated with poor prognosis of HCC patients. Our researches suggest that miR-1306–3p is a tumor enhancer in regulating of HCC metastasis, and miR-1306–3p may be clinically utilized as a factor for the clinical diagnosis and prognosis of HCC.

Yb2SiO5/mullite bi-layered coatings are promising environmental barrier coatings, but its molten salt corrosion mechanism is unclear. In this work, Yb2SiO5/mullite bi-layered coatings are fabricated by combining plasma spraying and dip-coating techniques. Residual stresses in the coatings caused by thermo-mechanical interaction are investigated by a nondestructive Raman spectrum method under high-temperature molten salt corrosion. In the as-deposited coatings, the stress in the mullite layer is compressive and the value near Si3N4 substrate is minimum. During high-temperature corrosion test, the residual stress near mullite-substrate interface changes sharply while the stress near mullite-Yb2SiO5 interface is concentrated without large fluctuation. An interfacial phase, YbAlO3, which is formed because of the inter diffusion of Al in the mullite layer and Yb in the Yb2SiO5 layer, causes the stress concentration. The change of SiO2 component in the mullite layer leads to the sharp change of residual stress near the mullite-substrate interface.

BACKGROUND: The balance of oxygen delivery and consumption is essential in patients who are critically ill. Mixed venous oxygen saturation (SvO2) is a standard method to evaluate oxygen delivery and consumption during anesthesia. However, SvO2 is monitored through a pulmonary artery catheter, which is invasive. Regional cerebral oxygenation (rScO2) reflects oxygen saturation in a small region of the frontal lobes and is monitored noninvasively through near-infrared spectroscopy. In the present study, the correlation between rScO2 and SvO2 was calculated during off-pump coronary artery bypass grafting surgery to determine whether a positive correlation exists between rScO2 and SvO2. METHODS: A total of 56 subjects were consecutively enrolled in the study. Then rScO2 and SvO2 were simultaneously monitored. The parameters were recorded at 5 time points: T1, 10 min after intubation (1.0 FIO2 for 10 min); T2, 20 min after intubation (0.60 FIO2 for 10 min); T3, at the end of the revascularization of the left anterior descending artery (0.60 FIO2); T4, after protamine infusion (0.60 FIO2); and T5, 10 min after protamine infusion (1.0 FIO2 for 10 min). The correlation between rScO2 and SvO2 and the variation trend between rScO2 and SvO2 when FIO2 increased from 0.60 to 1.0 were analyzed. RESULTS: There was a significant positive correlation between rScO2 and SvO2 at these 5 time points (r2 = 0.77, 0.81, 0.70, 0.83, and 0.92, respectively). There also was a significant positive correlation between Δ rScO2 and Δ SvO2 (n = 112, r2 = 0.72, P CONCLUSIONS: There was a positive correlation between rScO2 and SvO2 during off-pump coronary artery bypass grafting surgery, and there also was a positive correlation in the variation trend between rScO2 and SvO2.

Background The long-term pulmonary function and related physiological characteristics of COVID-19 survivors have not been studied in depth, thus many aspects are not understood. Methods COVID-19 survivors were recruited for high resolution computed tomography (HRCT) of the thorax, lung function and serum levels of SARS-CoV-2 IgG antibody tests 3 months after discharge. The relationship between the clinical characteristics and the pulmonary function or CT scores were investigated. Findings Fifty-five recovered patients participated in this study. SARS-CoV-2 infection related symptoms were detected in 35 of them and different degrees of radiological abnormalities were detected in 39 patients. Urea nitrogen concentration at admission was associated with the presence of CT abnormalities (P = 0.046, OR 7.149, 95% CI 1.038 to 49.216). Lung function abnormalities were detected in 14 patients and the measurement of D-dimer levels at admission may be useful for prediction of impaired diffusion defect (P = 0.031, OR 1.066, 95% CI 1.006 to 1.129). Of all the subjects, 47 of 55 patients tested positive for SARS-CoV-2 IgG in serum, among which the generation of Immunoglobulin G (IgG) antibody in female patients was stronger than male patients in infection rehabilitation phase. Interpretation Radiological and physiological abnormalities were still found in a considerable proportion of COVID-19 survivors without critical cases 3 months after discharge. Higher level of D-dimer on admission could effectively predict impaired DLCO after 3 months discharge. It is necessary to follow up the COVID-19 patients to appropriately manage any persistent or emerging long-term sequelae. Funding Key Scientific Research Projects of Henan Higher Education Institutions

Though therapy that promotes anti-tumor response about CD8

Water-soluble phosphorescent nanoparticles are highly desirable for biomedical applications. However, the phosphorescence of nanoparticles is usually quenched in aqueous solutions due to the nonradiative deactivation of triplet excitons by the oxygen in water, thus it is a huge challenge to realize water-soluble phosphorescent nanoparticles. Herein, ultralong and efficient phosphorescence has been achieved from water-soluble carbon nanodots (CNDs) by confine CNDs in a nanospace. Silica capsulation layer is used to ensure the solublity of the CNDs, isolate the CNDs from the surrounding oxygen in the aqueous solution. Furthermore, the motion and vibration of covalent bonds in the CNDs are limited. In this way, the nonradiative deactivation rates of triplet excitons has been decreased, and efficient phosphorescence is achieved from water-soluble CNDs. The lifetime and phosphorescence quantum yield of the CNDs are 1.86 s and 11.6 %, both of which are the best values ever reported for water-soluble phosphorescent nanoparticles. In terms of the efficient phosphorescence of the CNDs in aqueous solution, in vivo/vitro afterglow imaging is also been demonstrated.

The lungs are one of the most common target organs of diabetic injury in patients with diabetes. Long non-coding RNA (lncRNA) smoke and cancer-associated lncRNA 1 (SCAL1), also known as lung cancer associated transcript 1 (LUCAT1), is known to have a pivotal role in lung cancer. The aim of the current study was to investigate the potential involvement of SCAL1 in diabetic lung disease. The expression levels of SCAL1 were determined by reverse transcription-quantitative PCR in serum samples from healthy controls (n=40), diabetic patients without lung disease (n=56) and diabetic patients with diabetic lung disease (n=44). Receiver operating characteristic analysis was used to evaluate the diagnostic value of serum SCAL1 in discriminating diabetic patients with diabetic lung disease from diabetic patients without lung disease and healthy controls. Pearson's correlation analysis was performed to examine the correlation between SCAL1 and inducible nitric oxide synthase (iNOS) mRNA expression levels in blood and lung tissue samples. Expression levels of iNOS and NO production following treatment with high (30 mM) glucose were examined by western blot analysis and NO assay, respectively. The expression levels of SCAL1 were significantly downregulated in diabetic patients with diabetic lung disease, and downregulated serum expression levels of SCAL1 effectively distinguished diabetic patients with diabetic lung disease from diabetic patients without lung disease and healthy controls. Treatment with high glucose significantly upregulated SCAL1 expression in normal lung cells. Furthermore, the overexpression of SCAL1 inhibited iNOS protein expression and reduced NO production in cells treated with high glucose. In conclusion, the current study demonstrated that lncRNA SCAL1 inhibits iNOS protein expression in lung cells under high-glucose conditions, which suggests that SCAL1 may have potential in the treatment of patients with diabetic lung disease.

Aims. To examine the association between 4 single nucleotide polymorphisms (SNPs) of peroxisome proliferator-activated receptorsδ(PPARδ) polymorphisms and C-reactive protein (CRP) level and additional gene-gene interaction.Methods. Line regression analysis was performed to verify polymorphism association between SNP and CRP levels. Generalized multifactor dimensionality reduction (GMDR) was employed to analyze the interaction.Results. A total of 1028 subjects (538 men, 490 women) were selected. The carriers of the C allele (TC or CC) of rs2016520 were associated with a significant decreased level of CRP, regression coefficients was −0.338, and standard error was 0.104 (p=0.001). The carriers of the G allele (CG or GG) of rs9794 were also significantly associated with decreased level of CRP, regression coefficients was −0.219, and standard error was 0.114 (p=0.012). We also found a potential gene-gene interaction between rs2016520 and rs9794. Subjects with rs2016520-TC or CC, rs9794-CG or GG genotypes have lowest CRP level, difference (95% CI) = −0.50 (−0.69 to −0.21) (p<0.001), compared to subjects with rs2016520-TT and rs9794-CC genotypes.Conclusions. rs2016520 and rs9794 minor allele of PPARδand combined effect between the two SNP were associated with decreased CRP level.

The transient traveling waves generated by linghting can be used to linghting location, in order to improve fault identifiaction ability of current traveling wave location device, an identification method of lightning strike and short circuit fault based wavelet energy spctrum and transient waveform characteristics was presented in this paper. Through researched the current signals generated by non-fault lightning strike, fault lightning strike and short-circuit fault on 220kV transmission line, compared of the energy distribution of different transient signals in each prequence band, realized the identification of lightning strike and short-circuit fault; for lightning identification, by waveform characteristics calculated obtaining eigenvalue to identify the non-fault and fault linghtning. PSCAD/EMTDC simulation results identicate that the proposed method is correct and effective.

By using part of speech information to similarity calculation of paraphrase sentences, the similarity calculation method is improved. The improved method includes multi information of paraphrase text, such as, matching words information and part of speech information. A small-scale comparing experiment of double negation sentence paraphrase for two method of similarity calculation has been done, and the experimental results indicated effect of improvement method.

In order to improve the fault location accuracy, and eliminate the influence of spectral leakage in power transmission line fault location, we proposed a novel fault location scheme for transmission lines based on multi-measurements and phase comparison with Kaiser self-convolution windows FFT, which can locate the fault between two adjacent towers in the fault-prone segment. It is based Kaiser self-convolution window's excellent performance of leakage suppression, which can effectively solve the phase current fault component is relatively large errors due to spectral leakage problem. Firstly, this paper analyzes the causes of the phase spectrum leakage, then elaborates the sidelobe characteristics of Kaiser self-convolution window, and lists phase comparative fault location using steps, finally, verifies the correctness of the proposed method by simulation. The results show that the proposed method can effectively suppress spectral leakage, has a high location accuracy, a wide applicability and its solving of phase difference is precise.

The present paper describes the compulsively short circuiting transfer phenomenon of welding current in rotational arc MAG welding. Based on a previously reported model of spray transfer welding, a mathematical model of the short circuiting transfer of rotational arc welding is proposed. A series of welding experiments had been conducted and it’s results show that short circuiting transfer would take place when the welding gun electrode rotating to the sides of V groove. The relationship between the short circuiting transfer frequency and the arc rotational frequency also had been studied.

With high pressure spraying refinement technology of explosive, we obtain ultrafine powder of TATB and HMX. The middle diameter of them is 746 and 242 , that is to say those two kinds explosives belong to ultrafine explosive. Impact test indicate that the impact sensitivity of ultrafine TATB and HMX is decreasing in some degree. However the shock sensitivity is increased and the increased range is big. The end, we analyze this phenomenon and explain the reason that the ultrafine explosives` sensitivity is different form usual explosive in theory.

The characteristics of welding current in rotational arc GMAW were analyzed in this paper. It was found that the compulsively short circuiting transfer would take place when the electrode rotating to the sides of V groove. During the period of short circuiting transfer, the welding currents would sharply increase, so as to affect the average value of welding current in one rotational cycle. A novel method was proposed to detect the height of welding gun in this paper. The method use of least-square fitting method to fit the welding currents into a plane in three dimensions, and then through compute the distance between origin of coordinates and the plane to detect the height of welding gun. In the last, the validity of the method was proved through experiments.

Based on the principle of chaos suppression with the piecewise periodic perturbation, detection of weak periodic signals in strong noise is realized with controlled NBS (Novel butterfly-shaped) model. First, according to the parametric equivalent relationship obtained using segment control mechanism, the parameter range is determined in different periodic states of the chaotic system. Second, combined with Lyapunov exponent criterion, the critical values of detection parameters are determined, which lead to a sudden change of the system dynamical behavior from chaotic state to periodic 3. Finally, the numerical simulation and the measured signals experiment are performed. The results show that the method reacts sensitively for weak signals, possesses the better inhibitory action on the noise, and can effectively improve the signal-to-noise ratio.

Since there were a few articles to report the treatment of severe pulmonary vasoconstriction induced by protamine in cardiac surgery, we described the use of epoprostenol to reverse this condition. A total of 5 cases of severe pulmonary vasoconstriction induced by protamine in cardiac surgery were reviewed. The demographic, clinical data and treatment process were obtained. All the patients were followed up. Severe pulmonary vasoconstriction was occurred 4 to 10 minutes after protamine infusion. The primary sign was sudden hypotension, the pulmonary artery pressure was increased gradually, the arterial oxygen partial pressure was decreased in all the patients. Epoprostenol was infused via pulmonary artery catheter at dosage of 20 to 40 ng/kg·min in all the patients, 2 patients were underwent re-cardiac pulmonary bypass assistance. The hemodynamic instability status lasted 40 to 65 minutes respectively. All the patients were recovered uneventfully. All physicians should alert to the incidence of severe pulmonary vasoconstriction induced by protamine in cardiac surgery. Use epoprostenol through pulmonary artery catheter could treat pulmonary artery vasoconstriction effectively and safely.

Titanium alloys are extensively applied in the aircraft manufacturing due to their excellent mechanical and physical properties. At present, the α + β alloy Ti6Al4V is the most commonly used titanium alloy in the industry. However, the highest temperature that it can be used only up to 300 °C. BTi-6431S is one of the latest developed high temperature titanium alloys, which belongs to the near-α alloy group and has considerably high tensile strength at 650 °C. This paper investigates the machinability of BTi-6431S in the terms of cutting forces, chip formation and tool wear. The experiments are carried out in a range of cutting parameters and the results had been investigated and analyzed. The investigation shows that: (1) the specific cutting forces in the machining of BTi-6431S alloy are higher than in the machining of Ti6Al4V alloy; (2) the regular saw-tooth chips more easily formed and the shear bands are narrower in the machining of BTi-6431S; (3) SEM and EDS observations of the worn tools indicate that more cobalt elements diffuse into the workpiece from tool inserts during machining of BTi-6431S alloy, which significantly aggravates tool wear rate. The experimental results indicate that the machinability of BTi-6431S near alpha titanium alloy is significantly lower than Ti-6Al-4V alloy.

The identification of novel cytotoxic T lymphocyte (CTL) epitopes is important to analysis of the involvement of CD8+ T cells in Mycobacterium tuberculosis infection as well as to the development of peptide vaccines. In this study, a novel CTL epitope from region of difference 11 encoded antigen Rv3425 was identified. Epitopes were predicted by the reversal immunology approach. Rv3425‐p118 (LIASNVAGV) was identified as having relatively strong binding affinity and stability towards the HLA‐A*0201 molecule. Peripheral blood mononuclear cells pulsed by this peptide were able to release interferon‐γ in healthy donors (HLA‐A*02+ purified protein derivative+). In cytotoxicity assays in vitro and in vivo, Rv3425‐p118 induced CTLs to specifically lyse the target cells. Therefore, this epitope could provide a subunit component for designing vaccines against Mycobacterium tuberculosis.

To study the effects of L-arginine (L-Arg) on human colon carcinoma cell line LS174 through NO pathway and the mechanism.LS174 cells were cultured in the presence of L-Arg at different concentrations for different time. MTT assay was employed to evaluate the cell proliferation, and the cell morphological changes were observed by optical and electron microscopy. The apoptosis of L-Arg-treated cells was observed by the Annexin V/PI staining. The expression levels of VEGF, COX-2, p53, bcl-2 and bax in the cells were determined using Western blotting and immunocytochemical staining.L-Arg promoted the growth of LS174 cells at a low concentration (0.125 mmol/L) and inhibited the cell growth at higher concentrations (0.5, 2, 8, and 32 mmol/L). Under electron microscope, ultrastructual changes in the cytoplasm and nuclei of LS174 cells were observed 48 h after exposure to L-Arg. Some of the cells showed morphological changes characteristic of cell apoptosis such as cell size reduction, condensation and margination of the nuclear chromatin. Low concentration of L-Arg resulted in a cell apoptosis rate of 2.29%, as compared with the rate of 2.84% in the control group; at higher concentrations, L-Arg caused significantly increased cell apoptosis rates to 26.88%, 28.95%, 63.36%, and 84.51%, respectively. In cells treated with a low concentration of L-Arg, the expressions of VEGF and COX-2 were increased as compared with those in the control cells; higher concentrations of L-Arg obviously decreased the expressions of p53 and bcl-2 and increased the expression of bax.Low-concentration L-Arg can promote the growth of LS174 cells probably by up-regulating VEGF and COX-2 protein under the influence of NO, the metabolite of L-Arg. The inhibitory effect of high concentrations of L-Arg is probably mediated by inducing cell apoptosis via NO. The mechanism of L-Arg- induced cell apoptosis may be related to the up-regulation of bax protein and the down-regulation of p53 and bcl-2 proteins.

A novel and biomimetic restoration method for teeth by soaking in a simulated oral environment was reported. A biocompatible polydopamine (PDA) layer was deposited on the surface of dentin via dopamine polymerization to function- alize the surface to induce deposition of hydroxyapatite crystals. The samples were characterized by means of XPS, XRD, SEM and EDS. Results show that the coating of polydopamine layer induces the growth of hydroxyl apatite crystal on dentin surface, and improve the binding force between the hydroxyl apatite layer and the dentin surface. The optimized concentra- tion of dopamine solution is 2 mg/mL for the uniform deposition of PDA layer on the dentin surface.

In the present study, it was found that intraperitoneal (i.p.) pre-injection of N(G)-nitro-L-arginine methyl ester (L-NAME) significantly influenced the endomorphin-1 (EM-1) and endomorphin-2 (EM-2) induced antinociception. These effects could be inhibited or reversed by L-Arg or naloxone. Our results suggest that the modulatory effect of NO system on the mu-receptor evoked analgesia is different between the two mu receptor subtypes.