Clinical assessment research with older adults.

Methodological issues in geropsychological assessment research are discussed and exemplified with recent investigations. Increased use of short-term longitudinal designs, more diverse and representative sampling, and routine inclusion of measures of health are among the recommendations made for future studies. Caution is urged in the application of new tests or screening batteries until sufficient independent validation studies are completed. Research contrasting neuropsychological performance of older persons from different racial and ethnic groups is briefly reviewed, and applications of geropsychological assessment to practical arenas such as competency determination are critiqued. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

High-electric-field effects and degradation of AlGaAs/GaAs power HFETs: a numerical study

This work presents a numerical study of high-field degradation and reliability issues of AlGaAs/GaAs power HFETs. A commercial two-dimensional drift–diffusion tool is used to investigate electric-field distributions, the effects of electron capture at the device surface under hot-carrier conditions, and the impact of drain recess scaling on such effects. Wherever experimental data are available for direct comparison, a good match is observed with our simulations. The main results of this study are (1) a validation of the hypothesis that attributes the main high-field degradation effects to electron capture over the gate–drain access region, and (2) design indications pointing out to the possibility of a reverse correlation between the gate–drain breakdown voltage and the device hot-carrier reliability.     

A VSWR-protected silicon bipolar RF power amplifier with soft-slope power control

This paper presents the design and measured performance of a 1.8-GHz power amplifier featuring load mismatch protection and soft-slope power control. Load-mismatch-induced breakdown can be avoided by attenuating the RF power to the final stage during overvoltage conditions. This was accomplished by means of a feedback control system, which detects the peak voltage at the output collector node and clamps its value to a given threshold by varying the circuit gain. The issue of output power control has been addressed as well. To this end, a temperature-compensated bias network is proposed, which allows a moderate power control slope (dB/V) to be achieved by varying the circuit quiescent current according to an exponential law. The nonlinear power amplifier was fabricated using a low-cost silicon bipolar process with a 6.4-V breakdown voltage. It delivers a 33.5-dBm saturated output power with 46% maximum power-added efficiency and 36-dB gain at a nominal 3.5-V supply voltage. The device is able to tolerate a 10:1 load standing-wave ratio up to a 5.1-V supply voltage. Power control slope is lower than 80 dB/V between -15 dBm and the saturated output power level.     

异步电机性能微机测试系统设计

结合工程实际介绍了异步电机计算机辅助测试（CAT）系统的硬件、软件组成、技术方案确定以及设计原则。现场运行表明，该系统稳定可靠，且具有较高的性能价格比。     

Erythrocyte Na/K ATPase activity and diabetes: relationship with C-peptide level

The purpose of this study is to clarify the volume effect of epidural saline injection 20 min after spinal anesthesia. Thirty patients undergoing combined spinal and epidural anesthesia for orthopedic surgery were randomly divided into two groups: a control group (n = 15) and a saline group (n = 15). In the control group, 2% lidocaine 3 ml with 0.4% tetracaine was injected into the subarachnoid space from L 4-5 interspace using Durasafe (Becton Dickinson, USA) and saline was not injected into the epidural space. In the saline group, saline 10 ml was injected through an epidural catheter 20 min after spinal anesthesia. The levels of analgesia 20 min after spinal anesthesia were not significantly different between the groups. However, the levels of analgesia 3, 5, 10, 40 and 100 min after epidural saline injection in the saline group were significantly higher than those in the control group (P < 0.05). The highest analgesic level was obtained 10 min after epidural saline injection and reached to T 4.3 +/- 1.1. In conclusion, epidural saline injection increases the analgesic level 20 min after spinal anesthesia because of the volume effect.     

Body weight and risk of nonfatal acute myocardial infarction among women: a case-control study from northern Italy

BACKGROUND: The relationship between nonfatal acute myocardial infarction (AMI) and self-reported body weight and body mass index (BMI; Quetelet index, kg/m2) has been investigated. METHODS: A case-control study was conducted between 1983 and 1992 in northern Italy on 432 women with nonfatal AMI and 867 controls in hospital for acute, noncardiovascular, nonneoplastic, nondigestive, non-hormone-related conditions. Odds ratios (OR), with their 95% confidence intervals (CI), were computed by unconditional multiple logistic regression analysis, including terms for age, education, and smoking, plus history of selected diseases. RESULTS: Women with body weight and BMI in the highest quartile had an increased risk of AMI after allowance for age, education, and smoking status (OR 1.5, 95% CI 1.0 to 2.2, and OR 1.7, 95% CI 1.2 to 2.4, respectively). Compared with leaner women, the risk was higher among women with BMI above the median, in association with a history of diabetes (OR 5.2) or hyperlipidemia (OR 6.0). Hypertensive women had similar OR in the two strata of BMI (OR 5.1 and 4.8). The association of BMI with risk of AMI was apparently stronger among women younger than 50 years and among less educated women, but was similar among smokers and never smokers. CONCLUSIONS: The results of this study confirm that AMI among women is related to excess BMI, with a population attributable risk of 17%. The excess risk was substantial among overweight women with history of diabetes or hyperlipidemia, stressing the importance of controlling body weight among these women.     

Establishment of human parotid pleomorphic adenoma cells in culture: morphological and biochemical characterization

This study reports the establishment of alpha-amylase-producing human parotid pleomorphic adenoma cell lines (2HP and 2HP1) which have been maintained in culture for over 1 yr. The procedures required preparation of cellular clumps from tumor tissue and plating them on plasma clot or precoated dishes. During the initial phase of growth they required modified MCDB-153 medium without serum. When cells showed signs of degeneration they were changed to MCDB-153 medium containing first 2% and then 10% heat inactivated fetal bovine serum. Although cells grew well in MCDB-153 containing 10% serum, the epithelial cell morphology was not distinct. Therefore, the growth and morphology of cells grown in MCDB-10% serum were compared with those in RPMI growth medium containing 10% fetal bovine serum and F12 containing 10% agammaglobulin newborn bovine serum. Although the growth of cells was a little slower in F12 medium than those in MCDB and RPMI, the epithelial cell morphology was maintained better than in other growth media. The cells of 2HP and 2HP1 produce low levels of alpha-amylase and relatively high levels of alpha-amylase mRNAs of 1176 and 702 bp and contain neurofilament-160, a neuronal-specific marker. The cells of 2HP1 are tumorigenic when tested in athymic mice, but the cells of 2HP are not. The establishment of amylase-producing human parotid adenoma cell lines of different characteristics in culture provides a new opportunity to study the mechanisms of differentiation and transformation, and regulation of alpha-amylase in these cells.     

Electrochemical,FTIR and morphological study of polypyrrole—Polystyrenesulphonate conducting films

The electrochemical behaviour, FTIR spectrum and the morphology of polypyrrole-polystyrenesulphonate (PPy-PSS) films obtained potentiostatically at 0.6 V in a 0.05m Py + 1.7 × 10^?2m NaPSS medium have been analysed. Different electrochemical parameters have been modified in order to establish the first polaron formation, the reversibility of the redox process and the doping mechanism. The FTIR spectrum confirms the existence of C?O groups in the film structure and two possible explanations are suggested. SEM reveals a higher homogeneity in these films than in PPy films doped with smaller counterions.