The concentration of eco-toxic zinc oxide nanoparticles (nZnO) in aquatic ecosystems is increasing, and an effective method for their removal is needed. We hypothesize that microalgal cells may act as nZnO vehicles—if the nZnO concentration does not affect their swimming ability—enabling Zn diffusion and sedimentation. We conducted experiments using flasks connected via a U-type vessel; the first flask contained nZnO suspensions and second flask contained artificial seawater, respectively. We added microalgae to the first flask and illuminated the second. The microalgae appeared to promote sedimentation. However, only a few microalgal cells passed via phototaxis into the second flask, so the detection of nZnO or Zn ions in the second flask was not possible. Therefore, to confirm whether the microalgae affect Zn transportation, a more accurate method to detect nZnO or Zn ions at very low concentrations is needed.
We report the prevalence rates for dementia and Alzheimer's disease (AD) obtained from a probability sample survey of 5,055 noninstitutionalized older persons in Shanghai, China. A two-stage procedure was used for case finding and case identification. A Chinese version of the Mini-Mental State Examination was used to determine cases of possible dementia. Three different cutoff points on this mental status test were used depending on the respondent's level of education. Clinical evaluations, based on functional assessments and psychiatric interview, medical and neurological examinations, three standardized mental status tests, and a selected group of psychometric tests, were made in the second stage of the study to ascertain the clinical diagnosis of dementia and AD utilizing the Diagnostic and Statistical Manual for Mental Disorders, edition 3 and National Institute of Neurological and Communicative Disorders and Stroke-Alzheimer's Disease and Related Disorders Association criteria, respectively. The prevalence rate of dementia in persons 65 years and older was 4.6%. Clinically diagnosed AD accounted for 65% of the subjects with dementia. These findings indicate that the prevalence of dementia in Shanghai is very much higher than figures published earlier for China and Japan, and at the lower part of the range of values reported for community residents in the United States and other Western countries, but less than half of that reported in the recently published survey of the elderly in East Boston. Increasing age, gender (female), and low education are each highly significant and independent risk factors for dementia. One hypothesis to explain the increased prevalence in elderly women who had received no formal education invokes the possibility of an effect of early deprivation, perhaps lowering brain "reserve," allowing the symptoms of dementia to appear at an earlier date during disease progression. 相似文献
OBJECTIVE: To get the objective acoustic parameters of the voice of Beijing Opera actors and set a foundation for the training and protection of the special professional voice. METHODS: Seventy-three (age 16-57 years) professional actors and students were asked to produce sustained comfortable vowels /a/ and /i/, and to sing two pieces of songs which were in the category of Xipi and Erhuang respectively. Dr. Speech for windows version 3.0 was used to get the acoustic parameters of the vowels and the songs. RESULTS: F0 of the vowels /a/ and /i/ of different Hangdangs were Chou (272.6 +/- 42.0) Hz (mean +/- s), (304.2 +/- 22.1) Hz; Xiaosheng (499.3 +/- 34.0) Hz, (485.4 +/- 18.7) Hz; Laosheng (335.6 +/- 60.0) Hz, (317.9 +/- 45.1) Hz; Hualian (319.0 +/- 61.3) Hz, (340.1 +/- 68.8) Hz; Laodan (427.6 +/- 47.2) Hz, (437.7 +/- 45.8) Hz; Huadan (535.8 +/- 48.8) Hz, (561.6 +/- 29.2) Hz; Qingyi (548.0 +/- 69.5) Hz, (543.5 +/- 79.3) Hz; these and other acoustic parameters of vowels such as Jitter, Shimmer and NNE were all within the normal range given by the software. The vocal range of Beijing Opera actors was from 1.7 to 2.8 oct, and most of the highest and the lowest pitches were higher than that of tenor or soprano. CONCLUSIONS: These findings may help to provide insight regarding the acoustic characteristics of the voice of Beijing Opera actors. 相似文献
This study was aimed at the angiotensin converting enzyme (ACE) gene insertion/deletion(I/D) polymorphism distribution in Chinese and its relationship with serum ACE activity(SACE). SACE activity and ACE gene polymorphism in 90 healthy persons in Chengdu region were investigated using a spectrophotometric assay and the PCR technique, respectively. The results showed that, in the Hans, DD genotype of ACE gene was 18%, DI genotype 44%, and II genotype 38%. Allele frequencies were 0.40 for the D allele and 0.60 for the I allele. There were significant relationships between ACE I/D polymorphism and SACE activity. The results suggest that ACE genotype distribution be different between races, that II genotype and I allele be more frequent in Chinese, and that SACE activity be under the influence of a genetic polymorphism of ACE in Chinese. 相似文献