Association of Loss of Occlusal Pairs of Teeth with Sarcopenia in a Chinese Population of Community-Dwelling Elderly.

OBJECTIVES: Tooth loss, which usually leads to malnutrition, is common in the elderly. However, limited information is available regarding its association with sarcopenia. This study aimed to investigate the relationship between loss of occlusal pairs of tooth and sarcopenia. DESIGN: A cross-sectional retrospective study was performed. SETTING: The elderly who participated in the National Basic Public Health Project in the Maigaoqiao Community Medical Center in Nanjing, Jiangsu Province, China. PARTICIPANTS: A total of 2850 individuals aged ≥60 years were enrolled. MEASUREMENTS: Sarcopenia was defined according to the criteria proposed by the Asian Working Group for Sarcopenia. A trained dentist assessed oral health status and counted the number of present teeth. Logistic regression analyses were performed to evaluate the association between the loss of occlusal pairs and sarcopenia. RESULTS: The prevalence of sarcopenia was 7.1% (201/2850). Univariate logistic regression analysis showed that loss of occlusal pairs was associated with sarcopenia [anterior occlusal pairs (AOPs): odd ratio (OR) = 1.292, 95% confidence interval (CI) = 1.158-1.442; posterior occlusal pairs (POPs): OR = 1.147, 95% CI = 1.018-1.221]. Multivariate logistic regression analysis indicated that loss of POPs was still an independent risk for sarcopenia (OR = 1.108, 95% CI = 1.007-1.220) after adjustment for traditional confounders. Subgroup analysis showed that loss of POPs was more significantly linked to sarcopenia in those with advanced age (≥80years) (OR = 1.307, 95% CI = 1.116-1.532) and in females (OR = 1.165, 95%CI = 1.038-1.308). Compared to individuals with ≥5 occluding pairs of POPs, those with <5 occluding pairs of POPs had a higher incidence of sarcopenia. CONCLUSIONS: Loss of POPs is associated with an increased risk of sarcopenia in the elderly in a Chinese population. Further research on the mechanism of the observed causal relationship is needed.

Optics of ion beams for the neutral beam injection system on HL-2A Tokamak.

The ion beam optics for the neutral beam injection system on HL-2A Tokomak is studied by two- dimensional numerical simulation program firstly, where the emitting surface is taken at 100 Debye lengths from the plasma electrode. The mathematical formulation, computation techniques are described. Typical ion orbits, equipotential contours, and emittance diagram are shown. For a fixed geometry electrode, the effect of plasma density, plasma potential and plasma electron temperature on ion beam optics is examined, and the calculation reliability is confirmed by experimental results. In order to improve ion beam optics, the application of a small pre-acceleration voltage (∼100 V) between the plasma electrode and the arc discharge anode is reasonable, and a lower plasma electron temperature is desired. The results allow optimization of the ion beam optics in the neutral beam injection system on HL-2A Tokomak and provide guidelines for designing future neutral beam injection system on HL-2M Tokomak.

The dependence of extracted current on discharge gas pressure in neutral beam ion sources on HL-2A tokamak.

The discharge gas pressure is a key factor to influence the extracted current of ion source. In this paper, the dependence of extracted current on discharge gas pressure was investigated in detail at different arc discharge currents. The discharge gas pressure with a very broad range (0.1 Pa-2.7 Pa) was scanned for the first time. It is turned out that, with the increasing of discharge gas pressure, the extracted current increases and the arc voltage decreases at different arc currents; however, when the discharge gas pressure exceeds a certain value, the extracted current decreases. For the same discharge gas pressure, the higher the arc current, the higher the arc voltage and the extracted current are. The arc efficiency was also calculated, and its dependence on gas pressure was almost the same with the dependence of extracted current on gas pressure, but at the same discharge gas pressure, the lower the arc current, the higher the arc efficiency is and the lower the extracted current is.