Sustainable treatment of sewage sludge via plasma-electrolytic liquefaction for bio-friendly production of polyurethane foam.

Safe and green disposal or utilization of sewage sludge (SS) has attracted significant attention as SS is increasingly produced worldwide and emerges as an environmental burden if without proper treatment. In this study, efficient and sustainable treatment of SS was achieved using plasma-electrolytic liquefaction (PEL) with alkaline catalysts including sodium hydroxide (NaOH), sodium carbonate (Na2CO3), and sodium acetate (NaAc) and renewable solvents including polyethylene glycol (PEG) 200 and glycerol. Furthermore, the obtained bio-oil with abundant hydroxyl groups could partially replace polyols derived from fossil energy to synthesize bio-based polyurethane foams (BPUFs) for oil adsorption. The results showed that the Na2CO3 catalyst exhibited better performance and yielded bio-oil with a higher heating value (HHV) of 26.26 MJ/kg, very low nitrogen content (0.14%) and metal ions, and a nearly neutral pH of 7.41, under the optimized conditions. Compared with conventional oil bath liquefaction, PEL can significantly improve the liquefaction efficiency, promote the transfer of metal ions in SS to the solid residue (SR), and facilitate the transfer of nitrogen to the gas phase and SR, thereby upgrading the bio-oil to a certain extent. The BPUFs showed excellent oil adsorption capacity, reusability, and desorption and can play an important role in combating oil spills. The PEL method may provide a green avenue for SS valorization and the comprehensive utilization of the obtained products.

Acid Leaching Vermiculite: A Multi-Functional Solid Catalyst with a Strongly Electrostatic Field and Brönsted Acid for Depolymerization of Cellulose in Water.

Vermiculite is a natural mineral. In this study, vermiculite and acid-activated vermiculite was used as a solid acid catalyst for the hydrolysis of cellulose in water. The catalysts were characterized by XRD, FT-IR, and BET. The effects of time, temperature, mass ratio and water amount on the reaction were investigated in the batch reactor. The results showed that the highest total reducing sugars (TRS) yield of 40.1% could be obtained on the vermiculite activated by 35 (wt)% H2SO4 with the mass ratio of catalyst to cellulose of 0.18 and water to cellulose of 16 at 478 K for 3.5 h. The acid-activated vermiculite was a stable catalyst through calcination at 628 K and the yield of TRS decreased to 36.2% after three times reuse. The results showed that the crystal structure of vermiculite was destroyed and the surface -OH groups increased after the acid treatment. However, the synergistic effect of a strongly electrostatic polarization and Brönsted acid was responsible for the efficient conversion of cellulose. The mechanism of cellulose hydrolysis on the acid-activated vermiculite was suggested. This work provides a promising strategy to design an efficient solid catalyst for the cellulose hydrolysis, and expands the use of vermiculite in a new field.

Cold atmospheric plasma coupled with air abrasion in liquid medium for the treatment of peri-implantitis model grown with a complex human biofilm: an in vitro study.

OBJECTIVE: Treatment of implants with peri-implantitis is often unsuccessful due to residual microbial biofilm hindering re-osseointegration. The aim of this study was to treat biofilm-grown titanium (Ti) implants with different modalities involving air abrasion (AA) and cold atmospheric plasma (CAP) to compare the effectiveness in surface decontamination and the alteration/preservation of surface topography. MATERIALS AND METHODS: Saliva collected from a peri-implantitis patient was used to in vitro develop human biofilm over 35 implants with moderately rough surface. The implants were then mounted onto standardized acrylic blocks simulating peri-implantitis defects and treated with AA (erythritol powder), CAP in a liquid medium, or a combination (COM) of both modalities. The remaining biofilm was measured by crystal violet (CV). Surface features and roughness before and after treatment were assessed by scanning electron microscope (SEM). The data were statistically analyzed using Kruskal-Wallis followed by Tukey's multiple comparison test. RESULTS: In the present peri-implantitis model, the human complex biofilm growth was successful as indicated by the statistical significance between the negative and positive controls. All the treatment groups resulted in a remarkable implant surface decontamination, with values very close to the negative control for AA and COM. Indeed, statistically significant differences in the comparison between the positive control vs. all the treatment groups were found. SEM analysis showed no post-treatment alterations on the implant surface in all the groups. CONCLUSIONS: Decontamination with AA delivering erythritol with or without CAP in liquid medium demonstrated compelling efficacy in the removal of biofilm from implants. All the tested treatments did not cause qualitative alterations to the Ti surface features. No specific effects of the CAP were observed, although further studies are necessary to assess its potential as monotherapy with different settings or in combination with other decontamination procedures. CLINICAL RELEVANCE: CAP is a promising option in the treatment of peri-implantitis because it has potential to improve the elimination of bacterial plaque from implant surfaces, in inaccessible pockets or during open-flap debridement, and should stimulate the process of the re-osseointegration of affected dental implants by not altering surface features and roughness.

[Study on fatigue resistance of mechanical nickel-titanium files by phase-locked infrared flaw detection method].

PURPOSE: The movement trend of the posterior teeth and the distribution of the periodontal membrane stress were studied by using three-dimensional digital technology. METHODS: CBCT data of 88 patients admitted to our hospital from June 2017 to June 2022 were selected, and input into Mimics20.0 software for preliminary extraction of all parts and stored with STL files; then the data were repaired and optimized through Geomagic Studio 2014 software. With the help of normal phase extension, the invisible appliance and periodontal membrane were constructed. Finally, the six FEM models were simulated and observed by the current teeth in different groups. Statistical analysis was performed with SPSS 21.0 software package. RESULTS: The effect force of the largest periodontal membrane was distributed in the neck of the tooth, followed by the apical area, with the maximum effect force value in the NA group. In all accessory groups, the periodontal membrane maximum paradigm isoeffect force values of all patients in the accessory vertical rectangular group were significantly smaller than the values obtained in the horizontal rectangular group. CONCLUSIONS: The design of orthodontic tooth accessories has a strong inhibition effect on the position movement of anterior teeth during recovery, which improves the accuracy of tooth three-dimensional movement to a certain extent. Meanwhile, the normal equivalent stress of the periodontal membrane of patients in the initial application of the invisible appliance without brackets is large.

Comparison of Powered versus Manual Tooth Brushing for Safety and Efficacy in Patients with Gingivitis: A Randomised, Multicentre Clinical Trial in China.

OBJECTIVE: To evaluate the effects of powered and manual tooth brushing on gingival inflammation in a Chinese population with mild to moderate gingivitis. METHODS: The present randomised, single-blind, parallel clinical trial was conducted in five cities in China. Generally healthy participants aged 18 to 65 years, who were non-smokers and had at least 20 sites of gingival bleeding, were included as eligible subjects. The subjects were randomly assigned to either the powered tooth brushing (PTB) group or standard manual tooth brushing (MTB) group. All subjects were supplied with a fluoride-containing toothpaste, Gingival Bleeding Index (GBI), Modified Gingival Index (MGI) and the Turesky modification of the Quigley-Hein Plaque Index (MPI) were used to evaluate the outcomes. RESULTS: A total of 235 subjects completed the study, 118 in the PTB group and 117 in the MTB group. The mean age and sex distribution for the PTB and MTB groups were 34.40 ± 9.99 years, 89 women and 29 men, and 34.20 ± 10.14 years, 82 women and 35 men, respectively. After 6 months, the percentage decrease in MGI was 26.150% ± 26.897% for the PTB group and 14.768% ± 38.544% for the MTB group (P = 0.0092). Statistically significant differences between types of tooth brushing were also observed at 6 months for GBI, and at all time points for MPI. CONCLUSION: Tooth brushing with a powered toothbrush twice a day was shown to be more effective than use of a manual toothbrush in reducing gingival inflammation, gingival bleeding and surface plaque after a 6-month period. Both kinds of toothbrushes were safe for the oral tissues.

Novel technique using cold atmospheric plasma coupled with air-polishing for the treatment of titanium discs grown with biofilm: An in-vitro study.

OBJECTIVES: The aim of the present study was to assess the decontamination efficacy and titanium surface alterations of erythritol based air abrasion (AA) and cold atmospheric plasma (CAP) targeting a human complex biofilm. METHODS: Saliva collected from a peri-implantitis patient was used to develop in vitro human biofilm over titanium discs with machined (group A) and moderately rough (group B) surface. The discs were treated with AA, experimental CAP or a combination of both treatments (COM). The amount of biofilm on the discs was measured by crystal violet (CV). Surface features and roughness before and after treatment were assessed by SEM and laser profilometry, respectively. The data were statistically analyzed using Kruskal Wallis followed by Dunn's multiple comparison test after being checked for normality by Shapiro-Wilk test. RESULTS: All the discs in group A performed better to treatments compared to group B. In both groups, CV data showed significantly lower amount of biofilm after AA treatment compared to CAP (p<0.05). Cleaning efficacy revealed relevant decontamination of both the surfaces following AA and COM treatments and almost complete biofilm removal after AA application on group A (99.92%). SEM analysis demonstrated no post-treatment alterations on the discs and laser profilometry did not show statistically significant changes in Sa and Sdr values. SIGNIFICANCE: Decontamination with AA delivering erythritol with or without CAP is highly effective in biofilm removal from different titanium surfaces. All the tested treatments, including CAP showed no noticeable alterations of the titanium discs surface features. Further in vivo studies are necessary to understand the potential of CAP technology in implant surface decontamination.

Power-to-chemicals: Low-temperature plasma for lignin depolymerisation in ethanol.

Lignin valorisation into renewable fuels and platform chemicals is desirable but still encounters major challenges due to lignin's recalcitrant structure, and the lack of cost-, energy-, and material efficient conversion processes. Herein, we report a low-temperature plasma-based route to lignin depolymerisation at mild conditions. The discharge over ethanol surface locally creating a high-energy and reactive environment rich in free electrons, energetic H radicals, and other reactive species, is well suited for lignin depolymerisation. Furthermore, assisted with a Fenton reaction (by adding Fe2O3 and H2O2) to sustain a more oxidative environment, the lignin conversion yield increases from 42.6% to 66.0%. Thus-obtained renewable chemicals are rich in aromatics and dicarboxylic acid derivatives. The proposed strategy on intensifying reactive chemistry by high-power plasmas enables an effective power-to-chemicals conversion of lignin and may provide useful guidelines for modern biorefineries.

[Precise investigation of digital guide plates applied to implant surgery of anterior teeth].

OBJECTIVE: To study the precision of digital guide plates applied to the implant surgery of anterior teeth. METHODS: Fifty patients scheduled to receive implant restoration treatment in anterior teeth were enrolled in this study and divided into two groups (n=25, each group): those who were given routine implant restoration treatment (control group, 45 implants) and those who received implant restoration treatment using a digital guide plate (test group, 51 implants). After implantation, planned and placed implants were superimposed using digital software, and deviations (corona, apex, depth, degree) were analyzed. Esthetic parameters were assessed at 1 week (baseline), 6 month, and 1 year post final restoration. Pink esthetic (PES) and white esthetic (WES) scores were respectively used to evaluate the soft tissue and restoration esthetic outcome. RESULTS: The deviation parameters in the test group were significantly lower than those in the control group (P<0.05). PES and WES values recorded for the control group at 1 week, 6 month, and 1 year post final restoration were significantly lower than those in the test group (P<0.05). CONCLUSIONS: The digital guide plate can improve the accuracy of the three-dimensional position of implants in the maxillary esthetic zone. As such, this device may play an important role in obtaining the ideal aesthetic effects of maxillary anterior teeth.

Bioinspired Shear-Flow-Driven Layer-by-Layer in Situ Self-Assembly.

Layer-by-layer (LbL) assembly is widely applied as a coating technique for the nanoscale control of architecture and related properties. However, its translational applications are limited by the time-consuming and laborious nature of the process. Inspired by the blood-clotting process, herein, we develop a shear-flow-driven LbL (SF-LbL) self-assembly approach that accelerates the adsorption rate of macromolecules by mechanically configuring the polymer chain via a coil-stretch transition, which effectively simplifies and speeds the diffusion-controlled assembly process. The structural characteristics and surface homogeneity of the SF-LbL films are improved, and diverse three-dimensional structures can be achieved. Functional SF-LbL-assembled surfaces for corneal modification are successfully fabricated, and the surface of wounded rat corneas and skin can be directly decorated in situ with SF-LbL nanofilms due to the advantages of this approach. Furthermore, in situ SF-LbL self-assembly has promise as a simple approach for the wound dressing for interventional therapeutics in the clinic, as illustrated by the successful in situ fabrication of drug-free layers consisting of chitosan and heparin on the dorsal skin of diabetic mice to rescue defective wound healing. This bioinspired self-assembly approach is expected to provide a robust and versatile platform with which to explore the surface engineering of nanofilms in science, engineering, and medicine.

[Distribution Characteristics and Risk Assessment of Heavy Metals in the Sediments of the Estuary of the Tributaries in the Three Gorges Reservoir, SW China].

To investigate the pollution status of sediments at the junction of the Three Gorges Reservoir area, sediment samples were collected over four seasons from the junction of the estuary located at a tributary of the Ruxi River and the Yangtze River. The content of eight heavy metals (HMs), including Cr, Zn, Mn, Ni, Cu, As, Cd, and Pb, in sediments was determined by ICP-MS. The results showed the average levels of investigated HMs (in mg·kg-1) were Cr (45.24), Zn (46.46), Mn (406.14), Ni (20.885), Cu (12.49), As (7.02), Cd (0.253), and Pb (11.042). The distribution analysis indicated that the levels of HMs at the river mouth were higher than that of the tributaries of the middle reaches and the two sections nearby. The seasonal distribution shows that the heavy metal content in the spring sediment is higher than in summer, autumn and winter. In addition, the correlation analysis indicated that the eight HMs possessed similar homologous characteristics and had common exogenous inputs. The assessment of the Geo Accumulation Index showed slight Cd pollution in the estuary of Ruxi River, and the Potential Ecological Risk index showed that Cd presented moderate ecological risks. The toxic effect of benthonic organisms was possibly correlated to Ni contamination at the intersection of the tributary and main stream, which was supported by the evidence from the sediment quality criteria. In conclusion, the rating of ecological risk at the mouth of the Ruxi River tributary is slight.

The universality of lignocellulosic biomass liquefaction by plasma electrolysis under acidic conditions.

In this research, we compared the discharge characteristics and catalytic efficiency of sulfuric acid, p-toluenesulfonic acid, and their respective sodium salts (sodium sulfate and sodium p-toluenesulfonate) in sawdust liquefaction and found that sulfuric acid was the optimal catalyst when glycerol was used as solvent during the plasma electrolytic liquefaction (PEL) process. When sodium p-toluenesulfonate was used as the only catalyst, the liquefaction yield reached 83.51% after 25 min. This yield was higher than that obtained using sodium sulfate as the catalyst (60.63%) because different concentrations of H ions were produced in PEL. Cellulose, lignin, and holocellulose were extracted from sawdust and successfully liquefied in PEL, illustrating the universality of PEL. The optical emission spectra of the different biomass during the PEL process were similar, indicating that the kinds of free radicals produced were similar, which can accelerate the liquefaction of sawdust.

[Pegylated interferon alpha 2a in treating chronic hepatitis B patients].

OBJECTIVE: To evaluate the efficacy and safety of pegylated interferon alpha 2a (PEG-IFN alpha-2a) in treating patients with chronic hepatitis B. METHOD: Seventy-two patients with chronic hepatitis B were assigned to a PEG-IFN alpha-2a (experimental) group (n=42) and an interferon alpha (control) group (n=30) randomly. Each patient in the experimental group received 180 microg PEG-IFN alpha-2a every week. Each patient in the control group received 500 MU interferon alpha every day. All the patients were treated for 48 weeks, and then were followed for another 48 weeks with no treatment. RESULTS: At the end of the 12th week, the rate of HBeAg negative cases was 30% in the PEG-IFN alpha-2a group, which was much higher than in the control group (x2 = 4.162, P < 0.05). The values of HBeAg and the log value of HBV DNA in the PEG-IFN alpha-2a group were much lower than the values before the treatment (t = 2.689, t = 4.080, P <0.01), but there was no difference between before and after treatment in the control group ( t = 1.229, t = 1.009, P > 0.05). At the end of the 24th week, the rate of HBeAg negative cases in the PEG-IFN alpha-2a group was much higher than that in the control group (x2=6.190, P < 0.05). The value of HBeAg and the log value of HBV DNA in the PEG-IFN alpha-2a group were much lower than in the control group (t=2.215, t=2.122, P < 0.05). At the end of the 48th week, besides the reduction mentioned above, the rate of cases with HBeAg/antiHBe seroconversion and normalization of ALT and complete responsiveness in the PEG-IFN alpha-2a group were all much higher than those in the control group (x2=5.771, x2=5.617, x2=5.308, P < 0.05). At the end of 48 weeks with no treatment, all the parameters mentioned above in the PEG-IFN alpha-2a group were much better than those in the control group and they remained so, but they were different in the control group (x2=11.943, t=3.439, t=6.111, x2=9.930, x2=9.522, x2=7.920, P < 0.01). Nine patients in the PEG-IFN alpha-2a group had liver biopsies before their treatment and also at the end of their treatment. The expressions of HBsAg and HBcAg were decreased at the end of the treatment. The rate of expression of HBsAg in the liver tissues before the treatment was 88.9% but only 22.2% at the end of the treatment (x2=8.001, P < 0.01). The rate of expression of HBcAg in the livers before treatment was 66.7% but only 33.3% at the end of the treatment. Before and at the end of the PEG-IFN alpha-2a treatment, there were no significant changes in the degrees of inflammation and fibrosis and the quantity of collagen in the liver tissues. Three patients in the PEG-IFN alpha-2a group (10%) were HbsAg negative. Two of them were found so at the end of 32 weeks with treatment and one patient was found at the end of 24 weeks with no treatment, but there were no HBsAg negative patients in the control group. The adverse reactions that occurred in the PEG-IFN alpha-2a and in the control groups were similar. CONCLUSION: PEG-IFN alpha-2a was effective in inhibiting HBV replication. The effect of PEG-IFN alpha-2a was lasting. PEG-IFN alpha-2a was well tolerated during our treatment.

Preparation and chiral separation of a novel immobilized cellulose-based chiral stationary phase in high-performance liquid chromatography.

The chiral selector 6-azido-2, 3-di(p-chlorophenylcarbamoylated) cellulose was synthesized and further chemically immobilized onto 5-µm amino functionalized spherical porous silica gel. It was used as chiral stationary phase in high-performance liquid chromatography. Thirty racemates were successfully separated into enantiomers in either normal phase mode or reversed-phase mode. Good reproducibility and stability of the chiral stationary phase have been demonstrated.

[Enhanced role of the co-culture of thermophilic anaerobic bacteria on cellulosic ethanol].

Fermentation of the type of cellulosic materials to ethanol was evaluated in batch system of mono-cultures of cellulolytic ethanol producing strains (Clostridium thermocellum strain LQRI), and co-cultures of LQRI in combination with one of the non-cellulolytic ethanol producing strains (Thermoanaerobacter pseudoethanolicus strains X514 or Thermoanaerobacter ethanolicus 39E). Results showed that ethanol yields and cellulose degradation abilities were significantly improved by the establishment of co-cultures consisting of LQRI and Thermoanaerobacter ethanolicus partner. A factorial experimental comparison revealed that the co-culture of LQRI + X514 provided the higher ethanol yield than the co-culture of LQRI + 39E, but no significant difference on cellulose degradation by LQRI was found in these co-cultures. In the absence of yeast extract, the highest ethanol concentrations in the co-cultures of LQRI + X514 and LQRI + 39E were about 71 mmol/L and 36.5 mmol/L, which were approximately 5-11 and 3-5 times higher than that of the mono-culture LQRI under the same concentration substrate, respectively. In the presence of 0.6% yeast extract, the highest ethanol concentrations in the co-cultures of LQRI + X514 and LQRI + 39E were rapidly improved and reached 263.5 mmol/L and 143.5 mmol/L, which were approximately 8-22 and 8-12 times higher than that of the mono-culture LQRI under the same concentrations substrate, respectively. The maximum ethanol concentration reached about 263.5 mmol/L (1.2%) in the co-culture of LQRI + X514 grown on 5% Solka Floc in the presence of 0.6% yeast extract, while the maximum ethanol concentration reached 143.5 mmol/L (1.2%) in the co-culture of LQRI + 39E grown on 2% Solka Floc in the presence of 0.6% yeast extract.

[Cellulose degradation and ethanol production of different Clostridium strain].

Cellulose degradation and ethanol production of two types of cellulosic materials with different concentration were evaluated in batch system of mono-cultures of cellulolytic ethanol producing strains (Clostridium thermocellum strain LQRI and Clostridium thermocellum strain VPI), and co-cultures of LQRI or VPI in combination with one of the non-cellulolytic ethanol producing strains (Thermoanaerobacter ethanolicus strains X514 or Thermoanaerobacter ethanolicus 39E). Results demonstrated that higher cellulose degradation abilities about 1.2 times were detected in LQRI mono-culture than in VPI mono-culture, while no significant difference of ethanol yields was found between the two mono-cultures. Abilities of cellulose degradation and ethanol production decreased significantly with the increasing of substrate cellulose concentration (1%, 2%, 5%). In the co-culture system, cellulose degradation abilities of LQRI were also significantly higher than VPI, the former is 1.28-1.58 times of the latter. Cellulose degradation rate of LQRI + Thermoanaerobacter and VPI + Thermoanaerobacter decreased gradually with the increasing of substrate cellulose concentration, while the absolute value of cellulose degradation was also affected by the partner Thermoanaerobacter strain. Additionally, the ethanol yields in the co-cultures of LQRI + Thermoanaerobacter were significantly higher than that in the co-cultures of VPI + Thermoanaerobacter with same Thermoanaerobaeter partner, the former is 1.27-1.77 times of the latter. However, ethanol yields in the co-cultures have not significantly declined with the increasing of substrate cellulose concentration.

Analysis of cyclosporine A and its metabolites in rat urine and feces by liquid chromatography-tandem mass spectrometry.

A sensitive and specific liquid chromatography-tandem mass spectrometry (LC-MS/MS) method was developed and validated for the quantification of cyclosporine A (CyA) and the identification of its metabolites in rat urine and feces. The analytes were extracted from waste samples via liquid-liquid extraction. A Turboionspray source was used as a detector. It was operated in a positive ion mode with transitions of m/z 1225-->m/z 1112 for CyA and in a selected multiple reactions monitoring (MRM) mode with transitions of m/z 1239-->m/z 1099 for the internal standard (cyclosporine D, CyD). Linear calibration curves were obtained for CyA concentration ranges of 12.5-250 ng mL(-1) in urine and 2.5-375 ng mg(-1) in feces. The intra- and inter-day precision values (relative standard deviation) obtained were less than 8%, and the accuracy was within +/-15% for each of the analytes. Extraction recoveries of CyA and CyD were both over 80%. The identification of the metabolites and elucidation of their structure were performed on the basis of their retention times and mass spectrometry fragmentation behaviors. A total of seven metabolites in rat feces were identified as dimethyl CyA, hydroxy CyA, and dihydroxy CyA after the oral administration of cyclosporine A-Eudragit S100 nanoparticles (CyA-NP). Six of these metabolites were also detected in rat urine. A possible metabolic pathway was also proposed. The newly developed method was proven to be sensitive, simple, reproducible, and suitable for the rapid determination of CyA. It was successfully employed to study the excretion of CyA in rats and could be used to better understand the in vivo metabolism of CyA-NP, a potentially effective nanoparticle system.

[Treatment of skeletal Class II adult patients with microscrew implant anchorage and multi-loop edgewise arch wire].

OBJECTIVE: To evaluate the effects and mechanisms of the microscrew implant anchorage (MIA) combined with multi-loop edgewise arch wire (MEAW) technique in the treatment of skeletal Class II adult patients. METHODS: Eleven adult patients with skeletal Class II high-angle malocclusions were treated with fixed appliances. The spaces were closed by the springs from the MIA to the hook on the archwire. The height of the hook and the direction of the force were different according to the intrusion and retraction of upper anterior teeth. In the finishing stage, MEAW technique and modified class II elastics (from the first loop of MEAW to the MIA) were used for final detailing. Cephalometric analysis was used to evaluate the effect after treatment. RESULTS: After treatment, the decrease of SNA, ANB and FMA were (2.86 +/- 1.05) degrees , (2.82 +/- 0.96) degrees and (2.95 +/- 1.35) degrees , respectively. The torque control of upper anterior teeth was good. The protrusion of lower incisors and the molar extrusion were avoided. The upper molars were moved distally by (3.00 +/- 2.19) mm. CONCLUSIONS: The treatment of adult patients with skeletal Class II high angle malocclusions with MIA and MEAW technique could not only improve the facial esthetics but also avoided the common side effects of traditional Class II elastics.

Functional expression of thermo-transient receptor potential channels in dental primary afferent neurons: implication for tooth pain.

Temperature signaling can be initiated by members of transient receptor potential family (thermo-TRP) channels. Hot and cold substances applied to teeth usually elicit pain sensation. This study investigated the expression of thermo-TRP channels in dental primary afferent neurons of the rat identified by retrograde labeling with a fluorescent dye in maxillary molars. Single cell reverse transcription-PCR and immunohistochemistry revealed expression of TRPV1, TRPM8, and TRPA1 in subsets of such neurons. Capsaicin (a TRPV1 agonist), menthol (a TRPM8 agonist), and icilin (a TRPM8 and TRPA1 agonist) increased intracellular calcium and evoked cationic currents in subsets of neurons, as did the appropriate temperature changes (>43 degrees , <25 degrees , and <17 degrees C, respectively). Some neurons expressed more than one TRP channel and responded to two or three corresponding stimuli (ligands or thermal stimuli). Immunohistochemistry and single cell reverse transcription-PCR following whole cell recordings provided direct evidence for the association between the responsiveness to thermo-TRP ligands and expression of thermo-TRP channels. The results suggest that activation of thermo-TRP channels expressed by dental afferent neurons contributes to tooth pain evoked by temperature stimuli. Accordingly, blockade of thermo-TRP channels will provide a novel therapeutic intervention for the treatment of tooth pain.

[Experimental study of the transferred keratinocytes transplanted on biomembrane].

OBJECTIVE: To search an ideal carrier of transferred keratinocytes for transplantation. METHODS: The transferred keratinocytes were seeded on the surfaces of the artificial dermis and the silicone membrane and cultured in vitro for 2 weeks. The growth of the keratinocytes was observed by microscope and scanning electron microscope. RESULTS: The keratinocytes implanted on the artificial dermis began to rupture and died after 2 to 3 days. While the keratinocytes adhered well on the surface of silicone membrane with pseudopodia formation after 1 week under scanning electron microscope, and the cells kept normal morphological and proliferative properties 2 weeks later. CONCLUSION: The silicone membrane can be applied as an useful carrier for the keratinocytes transplantation.