Objective:To explore the value of reading report in upbringing the integrated faculties of medical students.Methods:To give the training of reading report to the Seven-year and the five-year program medical students in their last year.Results:Such a training stirred the students' learning interests,improved their abilities in independent study,promoted their ability in collecting and dealing with information and widened their knowledge.Medical students grasped of the essential methods in writing reading report,which settled the groundwork for research abilities in the future.Conclusions:Reading report writing is instrumental in de- veloping students' integrated faculties and worthy advocating in medical teaching.

Objective To investigate the influence of in vitro low-temperature degradation(LTD)treatment on the structural stability of 5 kinds of Y2O3 stabilized tetragonal zirconia polycrystals(Y-TZP)dental ceramics.Methods TZ-3YS powder was compacted at 200 MPa using cold isostatic pressure and pre-sintered at 1050℃for 2 h forming presintered blocks.Specimens were sectioned into 15 mm×15 mm×1.5 mm slices from blocks of TZ-3YS,Vita In-Ceram YZ,Ivoclar,Cercon Smart.and Kavo Y-TZP presintered blocks,18 slices for each brand,and then densely sintered.Specimens were divided into 6 groups and subjected to an accelerated aging test carried out in an autoclave in steam at 134℃,0.2 MPa,for 0,1,2,3,4,and 5 h.X-ray diffraction(XRD)was used to identify crystal phases and relative content of monoclinic phase was calculated.Specimens for three-point bending test were fabricated using TZ-3YS ceramics according to the ISO 6872 standard and bending strength was tested before and after aging.The polished and aging specimens of TZ-3YS and Cercon Smart zirconia ceramics were observed by atomic force microscopy(AFM)to evaluate surface microstructure. Resuits Tetragonal-to-monoclinic phase transformation was detected for specimens of TZ-3YS,Vita In-Ceram YZ,Ivoclar,and Kavo zirconia ceramics except for Cercon Smart ceramics after aging,and the relative content of monoclinic phase was increasing with the prolonged aging time.TZ-3YS was the most affected material,Kavo took the second,and Vita and Ivoclar were similar.Aging had no significant negative effects on flexural strength of TZ-3YS with average bending strength being over 1100 MPa.The nucleation and growth of monoclinic phase were detected by AFM in surface of Cercon Smart zirconia in which monoclinic phase was not detected by XRD.Conclusions The results suggest that LTD of dental Y-TZP is time dependent,but the aging test does not reduce the flexural strength of TZ-3YS.The long-term clinical serviceability of dental Y-TZP needs further observation.

OBJECTIVETo study the bonding characteristic of Titanium and RG experiment porcelain.

METHODS5 specimens with a size of 10 mm x 5 mm x 1.4 mm were cast from pure titanium. Then 1 mm of RG experiment opaque and body porcelain were fused on the surface of the titanium specimens. The interface of titanium and porcelain was analyzed with a scanning electron microscope with energy-despersive spectrometry; 6 metal specimens with the size of 25 mm x 3 mm x 0.5 mm were cast from Ni-Cr alloy and a uniform thickness of 1 mm of VMK 99 porcelain was veneered on the central area of 8 mm x 3 mm 18 metal specimens as the same size were cast from pure titanium. The uniform thickness of 1 mm of VITA TITANKERAMIK porcelain, of Noritake super porcelain Ti-22 and of RG experiment porcelain were veneered on every 6 specimens respectively in the central area of 8 mm x 3 mm. The specimens were subjected to a three-point bending test on a load-test machine with a span of 20 mm, then the failure loads were recorded and statistically analysised. The RG porcelain/titanium crown was fabricated by fusing RG opaque porcelain and body porcelain to cast titanium substrate crown.

RESULTSThe SEM results show no porosity and crackle were found in the interface. The energy-dispersive spectrometry show that there are Si, Ti and O in the 1 micro m layer between porcelain and titanium, which suggesting titanium and experiment porcelain bonding well. The three point test showed the fracture force for the combinations of titanium/VITA TITANKERAMIK porcelain, titanium/Noritake super porcelain Ti-22 and titanium/RG experiment porcelain were (7.233 +/- 2.539) N, (5.533 +/- 1.199) N and (6.316 +/- 1.433) N respectively. There were not statistically significant differences among them (t test, P < 0.01). The fracture force for the Ni-Cr alloy/VMK99 porcelain combination (12.733 +/- 3.297) N was significantly greater than those of the cast titanium/porcelain (t test, P > 0.05). The crown was translucent with no crack.

CONCLUSIONRG porcelain is well compatible with titanium.

Dental Porcelain ; chemistry ; Metal Ceramic Alloys ; chemistry ; Titanium ; chemistry

OBJECTIVETo obtain and investigate the chromaticity properties of colored dental 3Y-TZP ceramics with different colorant combinations.

METHODSColorant combinations were mixed with TZ-3Y-S powder, then the mixtures were compacted at 200 MPa using cold isostatic pressure, densely sintered at 1500 degrees C for 2 h forming 5 graded colored dental zirconia ceramics. Specimen were sectioned into 10 mm x 10 mm x 0.5 mm and 10 mm x l0 mmx 1 mm slices from the sintered blocks. Color measurement was performed under black background using spectrophotometer. The chromaticity properties were compared with that of the VITA In-Ceram YZ shade guide.

RESULTSFive colored dental zirconia ceramics were obtained. The lightness decreased gradually, and the chroma value increased gradually. The color differences of the two thickness specimens were little. The parameters of the color space were L*: 67.76-77.78; a*: -2.19-3.80; b*: 12.13-25.01, which was similar with that of the VITA In-Ceram YZ shade guide, while the lowest value of lightness was relatively higher than that of the VITA In-Ceram YZ shade guide.

CONCLUSIONColored 3Y-TZP dental ceramics are suitable for clinical use. There is a need to develop more darkness shaded zirconia dental ceramics.

Aluminum Oxide ; Ceramics ; Color ; Dental Porcelain ; Humans ; Zirconium

OBJECTIVETo investigate the structure, mechanical and low temperature aging properties of colored dental zirconia ceramics.

METHODS5 graded colored dental zirconia ceramics were made by adding colorants and their combinations into a 3Y-TZP (tetragonal zirconia stabilized by 3mol% yttrium) powder, the green body were compacted at 200 MPa, pre-sinter at 1,050 degrees C and maintained for 2 h, then densely sintered at 1,500 degrees C for 2 h. Specimens were cut from each of the 5 graded colored blocks. Physical, mechanical properties as well as chemical stability were tested, microstructure were observed, crystalline phase were identified by X-ray diffraction (XRD), aging properties were assessed by measurement of the relative content of monoclinic phase and bending strength testing.

RESULTSThe overall density of colored zirconia ceramics was over 99.7%, linear shrinkage was about 20%, while thermal expansion coefficient was about 11 x 10(-6) x degrees C(-1), the crystalline phase was tetragonal, bending strength was over 900 MPa which was slightly lowered than that of the uncolored zirconia, fracture toughness was slightly higher. Good chemical stability in acetic acid was observed. After aging treatment, tetragonal-to-monoclinic phase transformation was detected up to 40%, while bending strength was not significantly degraded.

CONCLUSIONThe results showed that colored 3Y-TZP ceramics presented good mechanical properties even after aging treatments, and was suitable for dental clinical use.

Ceramics ; Materials Testing ; X-Ray Diffraction ; Yttrium ; Zirconium

OBJECTIVEAn intrinsically colored machinable glass-ceramic containing tetrasilicic fluormica as the predominant crystal phase was studied, which was used in molar crown in dental CAD/CAM system.

METHODSOrthogonal design analysis was used to select appropriate base formula, coloration and heat treatment process.

RESULTSFactors influencing the color appearance of mica glass ceramic were nucleation agent and the ratio of Mg(2+) to K(+) in base formula; Cerium oxide (CeO(2)) was used as the main coloration; The preferred heat treatment was 650 degrees C for 1 h and 1,000 degrees C or 1,050 degrees C for 3 h - 4 h.

CONCLUSIONSThis mica glass-ceramic could provide 4 to 5 color appearance for dental use, it showed excellent machinability which was eminently suitable for use in dental CAD/CAM system.

Aluminum Silicates ; chemistry ; Color ; Computer-Aided Design ; Crowns ; Dental Porcelain ; chemistry ; Glass ; chemistry ; Molar

Objective To observe the effect of Bushen Jianpi Prescription,a prescription with the actions of tonifying the kidney and strengthening the spleen,combined with short-term intensive insulin therapy on dedifferentiation of pancreatic beta-cells in patients with type 2 diabetes mellitus(T2DM)of spleen and kidney deficiency type.Methods Seventy patients with T2DM of spleen and kidney deficiency type were randomly divided into control group and observation group,with 35 cases in each group.The control group was treated with intensive insulin therapy,and the observation group was treated with Bushen Jianpi Prescription on the basis of treatment for the control group.The course of treatment lasted for 2 weeks.The changes of TCM syndrome score,and levels of blood glucose,serum high mobility group protein B1(HMGB1),interleukin 1β(IL-1β),tumor necrosis factor α(TNF-α)and the ratio of proinsulin to insulin(PI/I)in the two groups were observed before and after treatment.Results(1)During the treatment,one case in the control group and 2 cases in the observation group fell off.Eventually,34 cases in the control group and 33 cases in the observation group were included in the efficacy statistics.(2)After treatment,the scores of TCM syndromes in the two groups were significantly lower than those before treatment(P＜0.05),and the decrease in the observation group was significantly superior to that in the control group(P＜0.05).(3)After treatment,the levels of fasting plasma glucose(FPG)and 2-hour postprandial plasma glucose(2hPG)in the two groups were significantly lower than those before treatment(P＜0.05),and the decrease in the observation group was significantly superior to that in the control group(P＜0.05).(4)After treatment,the level of HMGB1 in the two groups was significantly lower than that before treatment(P＜0.05),and the decrease in the observation group was significantly superior to that in the control group(P＜0.05).(5)After treatment,the serum levels of inflammatory factors of IL-1β and TNF-α in the two groups were significantly lower than those before treatment(P＜0.05),and the decrease in the observation group was significantly superior to that in the control group(P＜0.05).(6)After treatment,the PI/I ratio of the two groups was significantly lower than that before treatment(P＜0.05),and the decrease of the observation group was significantly superior to that of the control group(P＜0.05).Conclusion Bushen Jianpi Prescription combined with short-term intensive insulin therapy can effectively improve the islet function of patients with T2DM of spleen and kidney deficiency type.The mechanism may be related to the relief of high-glucose toxicity and the decrease of the inflammatory factor levels,thus to inhibit the dedifferentiation of pancreatic beta-cells.

OBJECTIVETo fabricate biomimetic biphasic calcium phosphate BCP ceramic scaffolds using three-dimensional (3D) gel-lamination technology and evaluated their structure with 3D parameters and related method.

METHODSSeries two-dimensional images of femoral head's specimen of dogs were obtained by micro-computed tomography (Micro-CT). According to these images, porous biomimetic biphasic calcium phosphate (BCP) ceramic scaffolds with oriented trabecular structure were fabricated by three-dimensional (3D) gel-lamination technology. And then, the three-dimensional structure of the scaffolds were reconstructed by computer according to Micro-CT images of these scaffolds and evaluated by three-dimensional parameters. These parameters included bone volume fraction (BVF, BV/TV), bone surface/bone volume (BS/BV) ratio, trabecular thickness (Tb.Th), trabecular number (Tb.N), trabecular spacing (Tb.Sp) and structure model index (SMI). The biomechanical properties and biocompatibility of these scaffolds were also evaluated in the study. Six scaffolds, which were combined with BMCs (bone mesenchymal cells, BMCs), were planted into the bone defect of six dogs' femoral head respectively.

RESULTSThere was no significant difference between trabecular samples and BCP scaffolds in BV/TV, Tb.Th, Tb.N, and Tb.Pf (P > 0.05). The trabecular system of the scaffold, which had some orientation, represented plate-like model. With a micro-porous porosity of 62%, the average compressive modulus and ultimate strength along the axis of the scaffolds reached (464.0 +/- 36.0) MPa and (5.6 +/- 0.8) MPa respectively. The results of animal test indicated that the trabeculae of these scaffolds were covered by a layer of new bone after 10 weeks of operation.

CONCLUSIONPorous BCP scaffolds have been produced with oriented microarchitectural features designed to facilitate vascular invasion and cellular attachment and with initial mechanical properties comparable to those of trabecular bone.

Animals ; Biomimetics ; methods ; Bone Substitutes ; chemistry ; Calcium Phosphates ; chemistry ; Dogs ; Female ; Male ; Materials Testing ; Prosthesis Implantation ; Structure-Activity Relationship ; Tissue Engineering

OBJECTIVETo investigate the effect of two methods of pigmentation on the flexural strength of dental Y-TZP/porcelain layered structure.

METHODSKaVo zirconia substructures were pigmented by dipping presintered blocks in the coloring solution VITA LL1 and LL5, and colored TZ-3YS zirconia substructures were fabricated by adding pigments before isostatic pressing. The colors No.1 and No.5 were used for the test. The specimens were made in monolithic or bilayered forms, and the flexural strength was tested. XRD and SEM with EDX were used to analyze the characteristics of the surface structure.

RESULTSIn KaVo group, no significant differences were found in the flexural strength between white and LL1 and LL5 colored monoclinic materials, nor in bilayered structures. While in TZ-3YS group, significant differences were noted in the flexural strength between color No.5 white and color No.1 monoclinic materials, but not between the latter two subgroups. The flexural strength was significantly lowered by veneering with porcelain in both zirconia groups, and similar findings were observed with the monoclinic materials. Only the tetragonal phase was detected in both of the zirconia groups.

CONCLUSIONPigmentation has no apparent effects on the bonding strength between the veneering porcelain and zirconia. Both coloring methods are appropriate when the concentration of the pigments is under deliberate control.

Dental Bonding ; Dental Materials ; Dental Porcelain ; chemistry ; Dental Stress Analysis ; Dental Veneers ; Materials Testing ; Pigmentation ; Tensile Strength ; Yttrium ; chemistry ; Zirconium ; chemistry

Hepatitis C virus (HCV) core protein is considered to be an attractive candidate for development of protective HCV vaccines. However, this protein may attenuate the induction of systemic immune responses due to its immunomodulatory properties. In this study, we constructed a HCV core gene-containing eukaryotic expression plamid pCI-C, and an in vivo-inducible prokaryotic expression plasmid pZW-C, and transformed the recombinant plasmids into an attenuated Salmonella typhimurium aroA strain SL7207. The resulting bacterial strains SL7207/pCI-C and SL7207/pZW-C were used to orally immunize BALB/c mice, and the immune responses specific to HCV core protein were assessed. Immunization with the recombinant bacteria SL7207/pCI-C led to a persistent drop in percentage of CD3 CD4 T cells, and induced a weak anti-core IgG production. Splenocytes from SL7207/pCI-C immunized mice developed a relatively weak proliferation response and inferior cytotoxic activity compared to those from the mice immunized with bacteria SL7207/pZW-C. Boost immunization with SL7207/ pCI-C yielded limited improvement in immune strength, while the boost with bacteria SL7207/pZW-C significantly enhanced the immune response. These results suggest that de novo synthesis of native HCV core protein may blunt the induction of immune responses. Attenuated S. typhimurium carrying HCV core protein could efficiently activate systemic cellular and humoral responses, and may be a promising strategy for the development of core-based HCV vaccines.
Animals ; Hepacivirus ; genetics ; immunology ; Mice ; Plasmids ; genetics ; Salmonella typhimurium ; genetics ; metabolism ; Vaccines, DNA ; immunology ; Viral Core Proteins ; genetics ; immunology ; Viral Hepatitis Vaccines ; genetics ; immunology