NM2:噪声地图和监测

噪声地图被公认是城市规划和管理的得力工具.不过它的可靠性和大众对它的信心在很大程度上取决于噪声地图是否可以通过利用噪声监测数据来校正和更新.此外,噪声地图应能反映因不断变化的交通情况而产生的噪声水平.通过回顾噪声地图在世界上在制作和应用上面对的问题,讨论其拥有噪卢监测功能的必要性,与作为协助决策者和广大群众做出合适决定...     

Salivary fluoride levels in overdenture wearers after topical fluoride gel application

This study describes salivary fluoride levels after topical fluoride gel application on overdenture abutments. Fluoride levels were evaluated separately for the subjects with normal unstimulated salivary flow rate (n = 16) and for those with a low flow rate (n = 8). One drop of fluoride gel (Karigel-N, Lorvic) was placed in two abutment depressions of the duplicated overdenture, after which unstimulated whole saliva was collected for 30 minutes. Samples for fluoride analysis were taken at 5-minute intervals. Two additional samples were taken at 45 and 60 minutes. Fluoride concentration at the abutment-denture interface (remaining fluoride concentration) was measured at the end of the study. Salivary fluoride concentrations decreased gradually in both groups of subjects, but after 1 hour they remained at a higher level in subjects with low flow rates. Subjects' salivary flow rates correlated negatively with remaining fluoride concentration at the denture-tissue interface. Consequently, mean remaining fluoride concentration was significantly higher in subjects with low flow rate than in their normal counterparts.     

Effects of a permanent magnetic field on 45Ca2+ ion influx in excitable and inexcitable cells and proliferative activity of rat spleen cells

When experimental animals were exposed to Permanent Magnetic Fields with magnetic induction (B = 0.2 T), the influx of 45Ca2+ ions into brain cells was activated, but the influx of 45Ca2+ ions into spleen cells was depressed. Similar effect was observed upon incubation of brain and spleen tissues in magnetized physiological solution. Incorporation of 3H-thymidine into spleen cells increased upon direct exposition to magnetic field and upon exposition of the spleen in magnetized physiological solution as well.     

SIDS cases have increased levels of interleukin-6 in cerebrospinal fluid

Cerebrospinal fluid (CSF) from 20 infants who died of sudden infant death syndrome (SIDS), 7 cases of infectious death and 5 cases of violent death were examined with respect to concentrations of interleukin-6 (IL-6). The measurements were performed by ELISA. IL-6 levels in SIDS were significantly lower than in infectious death (p < 0.02), but significantly higher than in violent death (p < 0.02). Since IL-6 plays an important role in immune responses and may induce fever, the findings may suggest that immune activation plays a role in SIDS. The presence of cytokines in the central nervous system (CNS) may cause respiratory depression, especially in vulnerable infants.     

Why do adults with mucoviscidosis refuse a medically recommended course of intravenous antibiotic therapy?

OBJECTIVE: To better understand the needs of spouses who provide care to spinal cord injury (SCI) survivors, by comparing their self-perceptions and complaints with those of their partners with disabilities and with those of spouses who do not provide care. DESIGN: Survey, including demographics, health concerns questionnaire, and administration of the Center for Epidemiologic Studies Depression Scale (CES-D), the Perceived Stress Scale (PSS), the Life Satisfaction Index (LSI-Z), and the Quality of Life and Individual Needs Questionnaire. SETTING: Two British SCI treatment centers, serving a defined population-based catchment area. PARTICIPANTS: One hundred twenty-four spouses of a longitudinally followed sample of SCI survivors, all of whom had been injured 23 or more years when the study was conducted in 1993. OUTCOME MEASURES: Scores on the above standardized tests, and responses to survey questions. RESULTS: Spouses had more depressive affect (p < .001) than their partners with disabilities, as measured by the CES-D. On the PSS, they exhibited no significant differences. Compared with spouses who were not caregivers, the caregiving spouses reported more physical stress (p = .005), emotional stress (p = .011), burnout (p = .007), fatigue (p = .002), and anger and resentment (p = .029). On the CES-D, they had more symptoms of depressive affect (p = .004) and somatic depression (p = .005). CONCLUSIONS: Spouses of long-term SCI survivors who fulfill a caregiving role report more symptoms of stress and depression than their partners with disabilities and other spouses who are not caregivers.     

On the Stress Intensity Factor for the Elliptical Crack

Stress intensity factor (SIF) for the elliptical crack under polynomial (uniform, as a special case) loading was first given by Kassir and Sih (1975). However, their expressions contain an error, corrected by Fabrikant (1987). This correction appears to have gone largely unnoticed, and some authors still use the incorrect result. We demonstrate, on the limiting case of a very elongated crack, that the correct expression is indeed the one of Fabrikant. This is hoped to resolve the controversy. It is also pointed out how to correct other results of Kassir and Sih for various loadings. This revised version was published online in August 2006 with corrections to the Cover Date.     

Effective mechanisms of ATX-S10, a new photosensitizer, on HeLa tumors in nude mice

Photodynamic therapy (PDT) is a treatment modality that utilizes a photosensitizing drug activated by laser generated light. PDT is effective for oncologic applications. Many cancer patients have undergone a hematoporphyrin derivative (HpD)-mediated PDT. The HpD showed a side effect causing prolonged cutaneous photosensitivity. But ATX-S10, a new photosensitizer, provides rapid plasma and tissue clearance, comparable photoactivation efficiency, and superior light absorption of visible red. In this study, the tumor rejection mechanisms of PDT using ATX-S10 on HeLa tumors in nude mice were investigated with morphological and fluorometric methods. The mice were intracutaneously inoculated with HeLa cells, 5 x 10(5) or 1 x 10(7) cells. When tumors grew to about 10-12 mm in diameter, mice were intraperitoneally administered ATX-S10, 30 mg/kg, and 2 hours later the ATX-S10 in tumors was indirectly measured by a fluorometric machine, PMA-10 (Hamamatsu Photonics K. K.) and the tumors were irradiated by Optical Parametric Oscillator (Hamamatsu Photonics K. K.) tuned to a wave length at 670 nm, 5 mJ/pulse, 100 J/tumor. Before and after the irradiation, the effective mechanisms of PDT with ATX-S10 were studied by histological and ultrastructural approaches. The results showed occlusive thrombi in the microvasculature of the tumors and tumor cell death. These occlusive thrombi were observed within one hour after PDT at both light and electron microscopy levels, and were more remarkable as time passed after PDT. Therefore, the morphological studies of PDT with ATX-S10 suggested that the rejection mechanisms occurred mainly as a result of the destructive changes of the microvasculature in the tumors first, and secondly or simultaneously, tumor cells were destroyed through necrosis, and finally the tumors were rejected.