BACKGROUND: Most of the dental metal repair materials contacting Ti implants will cause galvanic corrosion and local environment with positive electricity on the implant interface, which directly affects the status of the tissues, especially bone resorption.OBJECTIVE: To evaluate the galvanic corrosion of commercially pure Ti (TA2 type) coupled with Au alloy, CoCr alloy, Ti alloy, and NiCr alloy in vitro. METHODS: Circuit of commercially pure Ti contacting with Au alloy, CoCr alloy, Ti alloy, and NiCr alloy was simulated in vitro in artificial saliva, and the common potential and galvanic current in 15 hours were recorded to draw current-time curves. RESULTS AND CONCLUSION: The galvanic current became stable after 8 hours of contacting. The galvanic current was the greatest in Ti/Au, followed by Ti/CoCr, Ti/Ti alloy, and then Ti/NiCr. Results indicated that the galvanic corrosion of the couple of Ti and Au alloy is the lowest. Au alloy is the most suitable material for implant superstructure. The galvanic corrosion of the couple of Ti and NiCr alloy is the highest, so NiCr alloy is not acceptable for implant superstructure.

BACKGROUND:Domestic scholars use the potentiodynamic polarization technique to determine the corrosion potential of the dental aloys, which is used to evaluate the corrosion performance of the lownoble metal. They have discovered that the main reason affecting corrosion resistance is the content of noble metal. OBJECTIVE:To evaluate the corrosion resistance of Ti, Au aloy, Co-Cr aloy, Ti aloy, and Ni-Cr aloy. METHODS: Five aloys were immersed in synthetic saliva solution. The corrosion potential and corrosion current density of the aloys were determined with potentiadynamic polarization technique. RESULTS AND CONCLUSION:The galvanic series of five kinds of aloys were ranged as folows: Au aloy > pure Ti > Ti aloy > Co-Cr aloy > Ni-Cr aloy. Au aloy and pure Ti had more positive potential that were not easy to produce corrosion; Ti aloy and Co-Cr aloy could form stable oxidation film with a strong ability of anti-pitting and crevice corrosion; Ni-Cr aloy potential was more negative and easy to be dissolved. The corrosion current density of five kinds of aloys was ranged as folows: Au aloy < pure Ti < Ti aloy < Co-Cr aloy < Ni-Cr aloy. Au aloy and pure Ti had lowest current density which was 10-8, indicating that the corrosion rate of Au aloy and pure Ti was lower; in contrast, Ni-Cr aloy possessed the maximum corrosion rate. These findings indicate that Au aloy and pure Ti exhibit a very high corrosion resistance. The corrosion rate of Ni-Cr aloy is the highest; therefore, Ni-Cr aloy is the least acceptable material for implant suprastucture.

Humans ; Infant, Newborn ; Pain ; diagnosis ; etiology ; Pain Management ; Pain Measurement

Irritable bowel syndrome(IBS)is one of the most common functional gastrointestinal disorders,which severely affects the life quality of patients. Currently,the pathogenesis of IBS has not yet been clarified. Visceral hypersensitivity and central algesia abnormality may be involved in the pathogenesis of IBS. Antidepressants can improve abdominal pain,abdominal discomfort,mental disorders and abnormal defecation and enhance the quality of life. This article reviewed the advances in study on antidepressants in treatment of IBS.

Acupuncture Points ; Acupuncture Therapy ; instrumentation ; Aged ; Catgut ; Female ; Humans ; Male ; Middle Aged ; Muscle, Skeletal ; physiopathology ; Spasm ; physiopathology ; therapy ; Treatment Outcome

Humans ; Leukemia, Myelogenous, Chronic, BCR-ABL Positive ; metabolism ; Proto-Oncogene Proteins c-akt ; metabolism ; Signal Transduction

Objective: To understand the medical staff' cognition of medicalethics.Method: Descriptive study and various analysis were performed. Results: Four aspects including the understanding of hospital Ethic Review Committee, the status of medical ethics education, the understanding of medical ethics in clinic and research, the requirement of medical ethics training were surveyed among the medical staff in five hospitals. Conclusion: The influence of medical ethics in clinical practice and medical research were greatly improved. The hospital Ethic Review Committee should be strengthened and a lot of works was needed for medical ethics education.

Objective To study the development of hereditary dystrophic retina of rd mice and photoreceptors apoptosis. Methods Retinal sections of rd mice and their controls at different ages ranging from postnatal days 5 to 40 were examined by morphological(light and electronic microscope), morphometric and TUNEL analysis. Results Compared with age-matched control mice, the retinal dystrophy of rd mice began at postnatal days 10, resulting in rapid loss of photoreceptors and reaching a peak at postnatal days 18. TUNEL postitive nucleus of photoreceptor cells emerged from postnatal days 10 and reached a peak at postnatal days 14 and 16. Ultrastructure of photoreceptor cell layer showed marked nuclear pyknotosis and chromatin margination. Apoptotic bodies of photoreceptor cells were observed.Conclusion Rd mice retina degenerated during the process of maturity. Photoreceptor cell death occurred through apoptosis.

Female ; Follow-Up Studies ; Hearing Loss ; etiology ; Hearing Tests ; Humans ; Infant, Newborn ; Male ; Risk Factors

Micromachining of capillary electrophoresis chips is described.The current in channels was determined versus the voltage applied on the chip.Using laser-induced fluorescence detection,the process of injection and separation on chips was recorded with charge-coupled device(CCD).With defferent voltge of reservoirs on glass chips,profiles of the sample plug were studied. The elctropherogram of hydrolysis product of fluorescein isothiocyanate (FTTC-OH) and arginine labeled by fluorescein isothiocyante(FTTC-Arg) was obtained.