1.Effects of thermal and mechanical cycling on the metal-ceramic bond strength of machine-milled Ti2448 alloy and pure titanium.
West China Journal of Stomatology 2016;34(1):54-58
OBJECTIVETo evaluate the effects of thermal and mechanical cycling on the metal-ceramic bond strength of machine-milled Ti2448 alloy and commercial pure titanium (cp Ti).
METHODSCeramic-cp Ti (n = 30) specimens and ceramic-Ti2448 combinations (n = 30) were prepared in accordance with ISO 9693. The specimens from each metal-ceramic combination were randomly divided into three subgroups. In group A or the control group, the specimens were only stored in distilled water for 24 h at 37 °C; in groups B and C, the specimens were subjected to 3,000 cycles of thermal cycling between 5 and 55 °C for a dwell time of 60 s and to mechanical cycling of 20,000 or 40,000 cycles with 50 N load and 4 Hz in distilled water at 37 °C. A crack initiation test was performed using a universal testing machine in accordance with ISO 9693. Failure types at the metal-ceramic interface and the morphological and elemental composition of this interface were analyzed using a scanning electron microscope and an energy dispersive spectrometer. Statistical analysis was performed via two-way ANOVA and Tukey's adjustment test (α = 0.05).
RESULTSThe bond strength of the ceramic-Ti2448 combination was significantly higher than that of the ceramic-cp Ti combination regardless of fatigue conditions (44.86 MPa ± 1.75 MPa and 29.21 MPa ± 2.20 MPa for Ti2448 and cp Ti, respectively; P < 0.01). The mean bond strengths of ceramic-cp Ti and ceramic-Ti2448 combinations in group C were significantly lower than that of group A (P < 0.01). Although ceramic-cp Ti combination failed adhesively at the metal-ceramic interface without the ceramic on the substrate surface, Ti2448 frameworks exhibited cohesive failure; as a result, large amounts of residual porcelain were retained on the specimens.
CONCLUSIONThe metal-ceramic bond strength of cp Ti and Ti2448 is decreased by thermal and mechanical cycling.
Alloys ; Ceramics ; Dental Porcelain ; Materials Testing ; Metals ; Stress, Mechanical ; Temperature ; Titanium
3.The design and application of fully automatic X-ray exposure control
Yi LIU ; Yong-Bo LIU ;
Chinese Journal of Radiology 2001;0(05):-
Objective To realize fully automatic X-ray exposure controlling,simplify operating processes,and improve the quality of images.Methods We designed 5 or 7 X-ray detectors with silicon batteries,improved film-holding board of the main engine of the X-ray machine,then assembled them by mechanical gearing,and thus made multi-measured-limit,automatically-changed X-ray detectors.Results When choosing film boxes according to the radiographed positions,the detectors will change automatically into measured-limits coinciding with the interested positions.The average density was around 1Ⅴ in 9 randomly selected photographs.High quality was achieved in up to 98% of 10 000 radiographed images for clinic radiography.Conclusion The key of X-ray automatic exposure controlling technology is X-ray detecting technology,by which the quality of image can be improved.
4.Study on T-Cell and T-Helper Cell Subpopulation Function in Children with Recurrent Tonsillitis in Remission Period
Journal of Applied Clinical Pediatrics 1994;0(04):-
Objective To study the state of T-cell and T-helper cell subpopulation in children with recurrent tonsillitis(RT) in remission period and make clear its role on pathogenesis in children with RT.Methods The expression of membrane molecule on T-cell subsets was analyzed in 27 RT children and 21 control health children by using immunofluorescence and flowcytometry,the levels of interferon-?(IFN-?) and interleukin-4(IL-4) in culture supernatant of peripheral blood mononuclear cells(PBMC) were detected by enzyme linked immunoadsorbent assay(ELISA).Results The CD4~+ and CD3~+ cell were significantly lower in RT children than those of the controls(P0.05),a ratio of CD4~+/CD8~+ was disproportion(P0.05),the ratio of Th1/Th2 was disproportion(P
5.Study on inhibitory effect of EGCG on Calcium oxalate nephrolithiasis in rats and its related mechanism.
Yong ZHOU ; Shuo WANG ; Chun-bo TANG
China Journal of Chinese Materia Medica 2015;40(7):1376-1380
In the study, the inhibitory effect of epigallocatechin gallate (EGCG) on Calcium oxalate nephrolithiasis and its possible mechanism were investigated. The rat Calcium oxalate nephrolithiasis model was induced through the combined oral administration of ethylene glycol and ammonium chloride, which was intervened with EGCG. Rat blood samples were collected to detect blood creatinine (Cr), blood urea nitrogen (BUN) and blood calcium. Rat urine samples were collected to observe and compare 24-hour urine volume, oxalic acid (Ox) and calcium in urine. Renal samples were collected to prepare tissue slices and observe the pathological changes in Calcium oxalate nephrolithiasis. The expression of osteopontin (OPN) in renal tissues was evaluated by Real-time PCR and Western blot. According to the results, compared with normal rats, rats in the nephrolithiasis model showed significant increases in Cr, BUN, urine Calcium, urine Ox and renal OPN expression (P < 0.05), but obvious decrease in 24-hour urine volume (P < 0.05); Compared with rats with nephrolithiasis, those processed with EGCG revealed remarkable declines in Cr, BUN, urine Calcium and urine Ox (P < 0.05), with significant rise in 24-hour urine volume (P < 0.05) in a concentration-dependent manner. Additionally, compared with the control group, nephrolithiasis rats showed significant pathological changes in Calcium oxalate calculus. After ECCG treatment, the renal pathological changes and OPN expression attenuated significantly in a concentration-dependent manner. The results showed that EGCG inhibits the formation of calcium oxalate nephrolithiasis in rats and shows a notable protective effect on renal functions.
Animals
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Blood Urea Nitrogen
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Calcium
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blood
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Calcium Oxalate
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metabolism
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Catechin
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administration & dosage
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analogs & derivatives
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Creatinine
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blood
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Disease Models, Animal
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Humans
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Kidney
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drug effects
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metabolism
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Male
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Nephrolithiasis
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blood
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drug therapy
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genetics
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Osteopontin
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genetics
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metabolism
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Rats
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Rats, Wistar
6.Research on the Surface Potential Distribution of Spinal Cord Based on Finite Element Analysis.
Bo HONG ; Xiaoyan SHEN ; Yong LIU
Journal of Biomedical Engineering 2015;32(2):311-315
Finite element analysis can be used to study the change of the structure and the interior field intensity of human and animal body organs and tissues with simulation experiment. We in our research used finite element analysis software to analyze and solve the spinal cord surface potential problems, and investigated the transmission features of signals generated by interneurons in spinal nerves which were related with body motion control and sensory processing. A three dimensional model of electrical source in rat spinal cord was built, and the influence on potential distribution on spinal cord surface caused by position changes of electrical source in transverse direction and dorsoventral direction were analyzed and calculated. We obtained the potential distribution curves of spinal cord surface and found that the potential distribution on spinal cord surface showed monotone. In addition, potentials of some registration points were smaller than that of registration points around.
Action Potentials
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Animals
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Computer Simulation
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Finite Element Analysis
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Humans
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Interneurons
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physiology
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Models, Anatomic
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Rats
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Spinal Cord
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physiology
7.Expression of the hepatitis C virus proteinase isolated in Korean.
Journal of the Korean Society of Virology 1993;23(2):193-202
No abstract available.
Hepacivirus*
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Hepatitis C*
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Hepatitis*
8.A clinical study of the prognostic value of modified Glasgow prognostic score in patients with gas- tric cancer
Journal of Clinical Surgery 2014;(10):746-748
Objective To investigate the prognostic value of modified Glasgow prognostic score(mGPS)in patients with gastric cancer.Methods The clinical data of 600 patients with gastric cancerwho underwent surgical treatment were retrospectively reviewed.These patients were divided into themGPS0 group,mGPS1 group,and mGPS2 group according to the standard of mGPS.Postoperative survivals and risk factors that may affect patient's prognosis were analyzed among the three groups.Results There were 46 (7.7%)cases,33 (5.5%)cases and 521 (86.8%)cases in the mGPS0,mGPS1 andmGPS2 group,respectively.Except for gender(P =0.203),age,BMI,CEA,CA199,CRP,Alb,TNM stageand mGPS affected the over all survivals and there were significant differences among the groups(P <0.01).Gender,age,BMI,CEA,CA199 and TNM stage affected the mGPS and there were significantdifferences among the groups(P <0.01).Multivariate analysis identified that age(OR,1.319,95% CI1.068,1.629,P <0.01),TNMstage(OR,2.909,95% CI 2.616,3.234,P <0.01)and mGPS(OR,1.845,95% CI 1.184,2.875,P =0.007)were correlated with the postoperative death rate and they wererisk factors of poor postoperative prognosis(P <0.01).Conclusion mGPS can be used as an early,simple and effective prognostic predictor of postoperative survival for patients with gastric cancer.
9.Influence of IL-35 on occurrence and development of heart failure
Chinese Journal of cardiovascular Rehabilitation Medicine 2015;24(6):673-676
Heart failure is a syndrom of heart disease with high morbidity and mortality .There are more and more evidence indicating immune activation developing important role in the occurrence and development of heart failure . Interleukin (IL)‐35 ,known as a negative regulatory factor of one of the members of IL‐12 family ,participates pathogenetic process of heart failure .The present article made a review for influence of IL‐35 on heart failure .
10.Percutaneous kyphoplasty with bone cement injection for treatment of spinal metastases: changes of spinal stability and pain
Chinese Journal of Tissue Engineering Research 2015;19(16):2484-2488
BACKGROUND:Patients with spinal metastases may appear different degrees of pain and abnormal spinal stability, and can be treated with percutaneous baloon kyphoplasty combined with bone cement implantation. OBJECTIVE:To explore the effect of percutaneous baloon kyphoplasty with bone cement implantation on spinal stability and pain in patients with spinal metastases. METHODS:Twenty-three patients with metastatic spinal tumor were treated with percutaneous baloon dilatation kyphoplasty with polymethyl methacrylate bone cement. There were 10 females and 13 males, and their age ranged from 23 to 71 years. The visual analogue scale score, anterior and posterior edge height of vertebral body, quality of life, and motor function score of patients were observed before and after treatment. RESULTS AND CONCLUSION: Compared with before treatment, the visual analogue scale score and motor function score were significantly decreased, while anterior and posterior edge height of vertebral body were significantly increased in 23 patients at 24 hours after treatment (P < 0.05). After 12 months of folow-up, no case appeared to have spinal nerve root damage, serious adverse reactions and bone cement embolism. The patient'squality of life was significantly improved, compared with before treatment (P < 0.05). Experimental findings indicate that percutaneous baloon dilatation kyphoplasty with polymethyl methacrylate bone cement can significantly improve the spinal stability, relieve the degree of pain, and exert exact effects in treatment of spinal metastases.