BACKGROUND:Except for mechanical properties and physical and chemical properties, corrosion resistance testing is necessary for a variety of biomedical materials applied in the oral environment to ensure the biocompatibility of materials. OBJECTIVE:To explore the corrosion resistance of titanium abutment and different titanium aloysin vitro. METHODS:Corrosion environment byin vitroartificial saliva was constructed with pH=6.0 at (37±0.5)℃. Potentiodynamic polarization technique, scanning electron microscope and X-ray diffraction methods were employed to assess the corrosion resistance of titanium aloy, gold aloy, nickel-chromium aloy, and titanium abutment immersed in the artificial saliva for 24 hours. RESULTS AND CONCLUSION:Different aloys had different steady-state potentials, and the range of passivation region was the largest for gold aloy, folowed by titanium abutments and titanium aloys, and the smalest for nickel-chromium aloy. After 24 hours of immersion in the artificial saliva, passivation films appeared on the surface of different materials. under the scanning electron microscope, the nickel-chromium aloy surface showed obvious traces of corrosion and there were a large number of large-diameter deep pits, but no corrosion occurred on the surface of the remaining three kinds of aloys; on the surface of nickel-chromium aloy, the contents of chromium, molybdenum and aluminum were decreased, and the contents of nickel and oxygen were increased, but there were stil no changes on the surface of the remaining aloys. Cr2O3 was found on the surfaceof nickel-chromium aloy, TiO2 was generated on the surface of titanium abutment and titanium aloy, but Au and Pt stil existed in a single phase on the surface of gold aloy. These findings indicate that titanium aloy and titanium abutment have similar corrosion resistance that is inferior to the gold aloy, but better than the nickel-chromium aloy.

Objective To investigate the neuroprotective effect of panaxynol on primary cultured cortical neuron against oxidative stress. Methods Viability of panaxynol acted on neuron oxidative stress was monitored by MTT assay and FCM method. Scavenging effects of panaxynol on free radicals were observed in vitro. Effects of panaxynol on SOD activity and GSH-Px, and MDA content in primary neuron injured by H_2O_2 were also determined. Results Panaxynol (2—16 ?mol/L) could dose-dependently protect neuron from oxidative stress induced by H_2O_2; 8 ?mol/L of panaxynol could decrease necrosis and apoptosis rate of neuron significantly (P

Aim To evaluate neuroprotective effects of stearic acid on primarily cultured hippocampal neurons and to study the mechanism of neuroprotection afforded by stearic acid.Methods Primarily cultured hippocampal neurons were insulted by OGD(oxygen-glucose deprivation),H_2O_2,glutamate and NaN_3;MTT assay was utilized to evaluate cell viability;Inhibitors of PPAR?and PI-3K signal pathway were used to study mechanisms of neuroprotection of stearic acid.Results Compared with control neurons,A_(570) in MTT assay were increased significantly by stearic acid in hippocampal neurons insulted by OGD(oxygen-glucose deprivation),H_2O_2 and glutamate(P

Objective To study the enhancing effect of ultrasound plus microbubble on small interference RNA(siRNA)transfection in vitro and in vivo.Methods Human vascular epithelial growth factor(VEGF)siRNA with 2'deoxy modification(VEGF 2'-eoxy siRNA,VdsR)was used.The human CNE cells(fromnasopharyngeal carcinoma)line was used for in vitro cell-based experiments and in vivo mouse xenograft model.Two different microbubble agents.BR14 and Levovist.were used together with the RNA transfection reagent RNA-mate.ELISA and RT-PCR assays were used to assess VEGF gene expression.Immunohistochemical staining (IHC)was performed to assess CD31 expression in xenograft tumors.Results VdsR transfection in CNE cells abolished VEGF expression as determined by ELISA experiments.In the first mouse xenograft experiment,ultrasound exposure dramatically enhanced VdsR-mediated tumor inhibition.In the second mouse xenograft experiment,when VdsR was mixed with the microbubble reagents and then injected into xenografts,ultrasoundexposure significantly reduced tumor growth in BR14-mixed VdsR group but not in the Levovist-mixed VdsR group compared to the control.RT-PCR experiments demonstrated that VEGF expression in ultrasound-exposed tumors was significantly lower than that in the control.Meanwhile,VEGF expression in the tumor tissue treated by BRl4-mixed VdsR declined as compared with the controls.Tumor vascular density as measured by CD31 immunostaining was significantly decreased in ultrasound-exposed tumors compared to the control.Conclusions Ultrasound exposure and/or microbubble can significantly enhance delivery and the efficiency of VdsR-mediated anti-tumor effects,and should be a location-specific enhancement approach for siRNA-based anti-cancer therapy.

A new method was established for the direct, rapid and quantitative analysis of pesticide residues, dimethoate chlorothalonil and malathion by low temperature plasma ( LTP) ionization miniature ion trap mass spectrometer. The LTP ionization probe and sample inlet of ion trap mass spectrometry were enclosed in a metal cavity. With non-contact heating, the samples placed on the sample platform were desorbed into gaseous phase and ionized by LTP ionization probe. The results showed that closed ionization had an edge over the opened ionization. The quantitative analysis of 3 pesticides within the range of 0. 5-10 mg/L was realized by optimizing heating time and flow rate of air, and the relative standard deviations of signal intensity is less than 11%. LODs of pesticide, which were obtained within 5 s, were as low as several hundred pictograms. The results showed that the method could be used for the analysis of pesticide residue on green and organic fruits or vegetables.

BACKGROUNDTo isolate and identify the genes related to cancer metastasis by comparison of two cell strains with different metastasis potentials subcloned from human lung giant cell carcinoma cell line.

METHODSSuppression subtractive hybridization (SSH) was used to compare the levels of gene expression between the two cell strains and SSH library was constructed. After screening the library by gene chip, the expressed sequence tags (ESTs) with different expressing level were sequenced and blasted with GenBank.

RESULTSSeventy-nine genes were obtained that were expressed much higher in PLA-801D than in PLA-801C, including two full-length cDNA. GenBank Accession numbers of the two cDNA, named MAG-1 and MAG-2, were BC006236 and BC002420, the 8.5 kb MAG-1 gene was composed of four exons and located on the chromosome of 4q21. The MAG-2 gene, which was made up by 9 exons, had a length of 5.2 kb and its location was 2q35. Both sequences had open reading frames (ORF) and promoters before the theoretical transcription start points. Using special software, the secondary structure of theoretical products of the two cDNAs was prognosticated, α-helix was the main proportion, but β-pleated sheet and random coil were also included.

CONCLUSIONSThe expression of MAG-1 and MAG-2 has significant differences in these two cell strains, so they might impact tumor metastasis in some ways that are still uncharted.

OBJECTIVETo establish a reasonable protocol for interventional treatment of hepatocellular carcinoma (HCC).

METHODSThe data of 1 000 HCC patients treated by different kinds of interventional treatment were reviewed with their results of biochemistry, imaging, pathology and survival rate evaluated. The value as well as the pros and cons of these various kinds of interventional treatment were compared in order to find an optimum protocol.

RESULTSSegmental-transcatheter oil chemoembolization (S-TOCE) was much effective eradicate the tumor yet inflicting less damage on the noncancerous hepatic tissue and giving much higher survival rate than the conventional transcatheter oil chemoembolization (C-TOCE). Percutaneous ethanol injection (PEI) played an important role in eradicating the residual tumor and improving the survival rate without damaging the noncancerous hepatic tissue. The survival quality or survival rate could be improved by choosing different ways of interventional treatments to cut down the complications.

CONCLUSIONThe selection of different interventional treatments should be done according to the size and type of HCC. Active management is indicated for different complications presenting along with HCC.

Carcinoma, Hepatocellular ; mortality ; therapy ; Chemoembolization, Therapeutic ; Humans ; Liver Neoplasms ; mortality ; therapy ; Retrospective Studies ; Survival Rate

Objective:To explore any differential effect of training wearing a unilateral exoskeleton on the lower-limb motor function of stroke survivors.Methods:Forty stroke survivors were randomly divided into an exoskeleton group ( n=20) and a control group ( n=20). The control group performed conventional lower extremity exercise training while the exoskeleton group received exoskeleton-assisted lower-limb physical therapy. Each participant received eighteen 40-minute training sessions over three weeks. Before and after the intervention, the walking ability, lower-limb function, balance and ability in the activities of daily living of both groups were evaluated. Integrated electromyography (iEMG) of the rectus femoris and tibialis anterior of both legs was also recorded during sit-to-stand transitions to assess the activation of the affected muscles and the symmetry of bilateral muscle activation. Results:After the three weeks, significant improvement was observed in all of the measurements in both groups, but with the exoskeleton group scoring significantly better on average in functional ambulation category grading (1.63±0.72). Both groups′ iEMGs had also improved significantly compared with before treatment, but the exoskeleton group′s average result was by that time significantly better than the control group′s average.Conclusions:A wearable exoskeleton can effectively improve the rehabilitation of walking, lower limb movement, balance and skill in the activities of daily living of persons with subacute stroke. It better activates the affected lower limb muscles and improves the symmetry of bilateral lower limb muscle activation.

Objective: To analyze implant survival rate and incidence rate of complications after All-on-4 implantation, and to discuss the technical points and consideration of All-on-4. Methods : According to the criteria of inclusion and exclusion, 23 cases treated with All-on-4 immediate restoration were referred, from January 2007 to December 2015, including 5 cases of edentulous maxillary, 14 cases of edentulous mandibular and 4 cases of both maxillary and mandibular were edentulous. All the patients received immediate function with provisional prostheses at the surgery day. Definitive prostheses were delivered to patients after 3-6 months post operation and follow-up visits were performed up to 9 years (average 3 years) after placement of definitive prostheses. Results : In this study, the rate of implant retention of 108 implants and 27 final restorations was 100% until the last review. Among the 23 patients, 3 patients had complications and the incidence of complications was 13.0%. Conclusion All-on-4 is an effective and reliable method in the treatment of dentures denture. The incidence of complications is low. All-on-4 is a practical method.