OBJECTIVETo evaluate the effect of microwave sintering on the translucency of zirconia and to compare these effect with those of conventional sintering. The relationship between the microstructure of specimens and translucency was investigated.

METHODSA total of 10 disc-shaped specimens were fabricated from 2 commercial brands of zirconia, namely, Zenostar and Lava. Each group included 5 discs. Conventional sintering was performed according to the manufacturers' specifications. The maximum temperature for Zenostar was 1,490 °C, whereas that for Lava was 1,500 °C. The dwelling time was 2 h. The sintering temperature for microwave sintering was 1,420 °C, heating rate was 15 °C · min⁻¹, and dwelling time was 30 min. After sintering, the translucency parameter (TP) of the specimens were measured with ShadeEye NCC. The sintered density of the specimens was determined by Archimedes' method. The grain size and microstructure of the specimens were investigated by scanning electron microscopy.

RESULTSDensity and translucency slightly increased by microwave sintering, but no significant difference was found between microwave and conventional sintering (P > 0.05). Small and uniform microstructure were obtained from microwave sintering. The mean TP of Lava was significantly higher than that of Zenostar (P < 0.001).

CONCLUSIONThe translucency of zirconia sintered by microwave sintering is similar to that of the zirconia sintered by conventional sintering.

Ceramics ; chemistry ; Dental Prosthesis Design ; methods ; Heating ; Materials Testing ; Microscopy, Electron, Scanning ; Microwaves ; Surface Properties ; Technology, Dental ; methods ; Zirconium ; chemistry

objective: To observe the variations of stress magnitude in the cervical vertebra exerted by vertical traction force from various angles and different points. Methods: The cervical vertebra model was produced by using elastic material of light (polycarbonate) and silica rubber(1:1). By calculating the arithmetical progression of interference fringe. The author judged the stress magnitude in the posterior edge of the C4-7 vertebral bodies when different kinds of pulling force acted on. Result: The interference pattern was seen clearly on the screen while the force acted on the model. When the pulling force acted on C1 or C2, the force was acting at an angle of 150the maximum of the stress presented in C4-5 and when the force acted at an angle of 25° the maximum stress presented in C5-6 and C6-7. Conclusion: The stress distributed upon the posterior edge of the vertebral joints is closely related to the points that the force aced on and the direction of the force． Appropriate points and direction of the pull should be selected according to the change of the lesion joints when manual manipulation is used for the treatment of cervical vertebral disease.

AIM: To investigate mutations of oncogene k-ras in colorectal cancer tissues and the relationship between mutations of k - ras and biological behavior of colorectal carcinoma. METHODS:The specimens of 123 patients with colorectal cancer were collected. Real - time fluorescence quantitative PCR were performed to detect k-ras mutations at codon 12 and codon 13 of exon 1, and the results were analyzed with the corresponding clinical pathological data. RESULTS: Among 123 colorectal cancer cases, point mutations were detected in 53 cases (40.8% ) , point mutations at codon 12 were found in 42 (34.1 % ) cases, and 11(8.9% ) cases at codon 13.No closely relationship between mutations of k-ras and tumor size, location, invasive depth and differentiation extent was observed. The rate of k-ras mutation in the cases with more invaded lymph nodes was higher than that in the cases without invaded lymph nodes ( P < 0.05 ) , and the rate of k-ras gene mutation in the cases with hepatic metastases was higher than that in no hepatic metastases (P <0.05). The rate of k - ras gene mutation was higher in TNM staging Ⅲ/Ⅳ than that in Ⅰ/Ⅱ( P < 0.05 ). CONCLUSION: Mutation of oncogene k-ras plays an important role in the carcinogenesis and development of colorectal cancer, and it is closely associated with invaded lymph notes and hepatic metastases, suggesting that mutation of k- ras indicates a poor prognosis.

Objective To study the effect of operative modalities on the prognosis of gastric carcinoma patients suffering from various types of intra-abdominal metastasis. Methods In this study, 150 cases of gastric cancer with abdominal metastasis screened from data base, were divided by the location into peritoneal dissemination group (n=106), hepatic metastasis group (n=19) and both peritoneal dissemination and hepatic metastasis group (n=25). The surgical interventions include total resection, palliative resection and no resection. The clinicopathological parameters and prognosis were analyzed. Results The total tumor resection rate in peritoneal dissemination group (48.1%) and hepatic metastasis group (63.2%) was significantly higher than that in both peritoneal and hepatic metastasis group (20.0%), with the mean survival time (months) being 31.1, 12.8, 9.7 respectively (P<0.05). In peritoneal group, the mean survival (months) for tumor total resection, palliative and no resection subgroup was 46.3,1.7,4.8 respectively (P<0.05), whereas in hepatic metastasis group, the mean survival (months) was 17.2,4.0,5.4 respectively (P<0.05), in both peritoneal and hepatic metastasis group, the mean survival (months) was 11.2,8.9,5.0 respectively (P>0.05). Lymph nodes resection significantly prolonged survival in peritoneal dissemination group. Conclusions The prognosis of gastric cancer with peritoneal dissemination is better than with hepatic metastasis. Tumor total resection and lymph node dissection significantly improve the survival of patients suffering from peritoneal or hepatic dissemination.

Objective To explore the comprehensive therapy of infants with urinary calculus induced by melamine.Methods Clinical data of 228 infants(aged from 4 months to 3 years,mean age 11 months)with urinary calculus induced by melamine were analyzed. Bilateral renal calculi were found in 144 cases and one-side renal calculus in 54 cases,of which the diameter ranged from 0.5-2.5 cm.Ureteral calculi with moderate to severe hydronephrosis were found in 15 cases,of which the diameter ranged from 0.4-1.1 cm. Bladder calculi with urinary retention were found in 5 cases and urethral calculi with urinary retention in 10 cases,of which the diameter ranged from 0.5-1.3 cm. All the urinary calculi were confirmed by B-uhrasound examination and CT. Group 1 : Of the 15 cases with acute renal failure, 13 underwent shattering and dissolving renal and ureternal calculus by pelvis clysis with alkalinity drug, detaining double J tubes through ureteroscope. After operation, these patients were treated with alkalinity drugs. Two cases were treated by percutaneous nephrostomy guided by B ultrasound and underwent shattering and dissolving renal calculus by intermittent pelvis clysis with alkinity drug. Group 2:15 cases of ureteral calculus with serious nephrohydrops underwent shattering and detaining double J tubes through ureteroscope, then treated with alkalinity drug. Group 3:15 cases of infant bladder and urethral caleus with acute urinary retention were treated by EMS through ureterscope per urethra. Group 4: The rest 183 cases without urinary obstruction received 1-8 week'surine alkalization therapy. Among them, 113 cases received sodium bicarbonate 0.15 g twice per day,23 cases received potassium sodium hydrogen citrate 2.4g/d, and 47 cases received 10% potassium citrate solution 5 ml 3 times per day. Sixty-one cases who were of no effect with alkalinity drug were treated by extracorporeal shock wave lithotripsy (ESWL) and dissolving calculus with sodium bicarbonate. During treatment with alkalinity drug, urine Ph was observed by urine analysis once per day.When it exceeded 7.5, alkalinity drug. Was withdrawn. All the patients were followed up for 1 to 3 months. Statistical analysis was done with the SPSS 13.0 software. ResultsHyperdiuresis emerged 12-24 h after operation in group 1. The duration of hyperdiuresis was 24-72 h with the urine volume of 800-2500 ml/24h. Urine volume revived gradually 48--96h after operation while serum BUN and Cr revived 1-5 d after operation. Four cases with renal and ureteral calculus became almost stone-free in 1-2 weeks and 14 cases became completely stone-free in 2-4 weeks after operation. Patients of group 2 became completely stone-free in 1-2 weeks. Patients of group 3 were cured by one EMS session through ureterscope per urethra and smooth urination was seen immediately after operation. No retained calculus in the bladder and urethra was found by B ultrasound 3 days later. In the sodium bicarbonate group, 4 cases became completely stone-free in 2 weeks, 18 cases in 4 weeks, 15cases in 13 weeks. The stones lessened and faded in 34 cases and had no changes in 42 cases. In the potassiun sodium hydrogen citrate group, 4 cases became completely stone-free in 1 weeks, 7 cases in 2 weeks, 10 cases in 4 weeks, 2 cases in 6 weeks. In the potassium citrate group, 3 cases became completely stone-free in 1 weeks, 5 cases in 2 weeks, 16 cases in 4 weeks, 11 cases in 8 weeks. The stones lessened and faded in 8 cases in 8 weeks and had no changes in 4 cases. The efficacy of the sodium bicarbonate group was significantly different with the efficacy of the citrate group (P=0. 001). No significant difference was found between the potassium sodium hydrogen citrate group and the potassium citrate solution group(P=0. 372). ConclusionsConservative treatment should be employed mainly in the earlier stage for the infant urinary calculus induced by melamine . When the diagnosis of acute renal failure, moderate to severe hydronephrosis and acute lower urinary tract obstruction are established, surgical intervention should be the main method to relieve obstruction, protect renal function and resume normal rnicturition. With the development of the characteristics of the stones later,the oral dissolution therapy with alkalirtity drug could not dissolve the calculi and ESWL should be employed.

Objective:To analyze the epidemiological characteristics and economic burden of palmoplantar pustulosis (PPP) in China.Methods:A population-based retrospective study was conducted using the data from China′s Urban Basic Medical Insurance data from January 1, 2012, to December 31, 2016. International Classification of Diseases code and diagnoses in Chinese for PPP were used to identify cases and estimate the prevalence, incidence, and cost. Subgroup analyses were performed according to age and sex, and sensitivity analyses were conducted to evaluate the robustness of the results. Age-adjusted prevalence rates were calculated based on the 2010 national census data.Results:The crude prevalence and incidence rate of PPP in 2016 were 2.730/100 000 (95% CI: 2.218/100 000-3.242/100 000) and 1.556/100 000 (95% CI: 1.154/100 000-1.958/100 000), and the prevalence rate of females (2.910/100 000) was higher than that of males (2.490/100 000, χ2=97.48, P=0.001). The incidence rate of females (1.745/100 000) was also higher than that of males (1.418/100 000, χ2=85.02, P=0.001). The age peak of incidence and prevalence of patients with PPP was in the 30-39-year age group and a small peak existed in the 0-3-year age group among people under 20 years old. From 2012 to 2016, the average number of visits was (2.44±0.04) per patient, and the total per-capita cost per year was (982.40±39.19) yuan. Conclusion:In 2016, the prevalence and incidence rate of PPP in China were higher in females than in males, and the highest age peak was in the 30-39-year age group.

Objective:To analyze the epidemiological characteristics and economic burden of palmoplantar pustulosis (PPP) in China.Methods:A population-based retrospective study was conducted using the data from China′s Urban Basic Medical Insurance data from January 1, 2012, to December 31, 2016. International Classification of Diseases code and diagnoses in Chinese for PPP were used to identify cases and estimate the prevalence, incidence, and cost. Subgroup analyses were performed according to age and sex, and sensitivity analyses were conducted to evaluate the robustness of the results. Age-adjusted prevalence rates were calculated based on the 2010 national census data.Results:The crude prevalence and incidence rate of PPP in 2016 were 2.730/100 000 (95% CI: 2.218/100 000-3.242/100 000) and 1.556/100 000 (95% CI: 1.154/100 000-1.958/100 000), and the prevalence rate of females (2.910/100 000) was higher than that of males (2.490/100 000, χ2=97.48, P=0.001). The incidence rate of females (1.745/100 000) was also higher than that of males (1.418/100 000, χ2=85.02, P=0.001). The age peak of incidence and prevalence of patients with PPP was in the 30-39-year age group and a small peak existed in the 0-3-year age group among people under 20 years old. From 2012 to 2016, the average number of visits was (2.44±0.04) per patient, and the total per-capita cost per year was (982.40±39.19) yuan. Conclusion:In 2016, the prevalence and incidence rate of PPP in China were higher in females than in males, and the highest age peak was in the 30-39-year age group.