Blood lead levels in Taiwanese adults: distribution and influencing factors

Five-thousand nine-hundred thirteen Taiwanese adults were selected by multistage sampling methods to investigate environmental lead exposure in Taiwan. The blood specimens were distributed to six laboratories for blood lead levels (BLL) measurement. The mean BLL of the 5913 Taiwanese adults was 8.28 ± 5.39 μg/dl, with a maximum level of 57.6 μg/dl. The median was 7.0 μg/dl and 90th percentile was 15.0 μg/dl. BLLs were associated with gender, ethnic group, education level, smoking, alcohol consumption, herbal drug consumption, milk consumption, sources of drinking water, level of urbanization, and occupational lead exposure. These results showed that BLLs in Taiwanese adults were stable during the 2-year study. Most of the influencing factors were consistent with other studies, while local risk factors, such as Chinese herbal drug consumption are important ways of preventing the general population from overexposure to lead.     

Predictors of systemic embolism in patients with mitral stenosis. A prospective study

BACKGROUND: Most studies of the predictors of systemic embolism in patients with mitral stenosis have been retrospective. OBJECTIVE: To prospectively study factors associated with systemic embolism in mitral stenosis. DESIGN: Prospective cohort study. SETTING: University-affiliated medical institution with 3000 beds. PATIENTS: 534 consecutive patients with a mitral valve area of 2.0 cm2 or less; 132 patients were in sinus rhythm, and 402 were in atrial fibrillation. MEASUREMENTS: Nine clinical and 10 echocardiographic variables were assessed for prediction of systemic embolism over a mean (+/- SD) follow-up of 36.9 +/- 22.5 months. Diagnosis of systemic embolism was based on symptoms and signs (sudden onset of peripheral arterial ischemic or neurologic manifestations without prodromes) and on findings on computed tomography, angiography, and surgery. RESULTS: For patients in sinus rhythm, age (relative risk [RR], 1.12 [95% CI, 1.04 to 1.21]), the presence of a left atrial thrombus (RR, 37.1 [CI, 2.82 to 487.8]), mitral valve area (RR, 16.9 [CI, 1.53 to 187.0]), and the presence of significant aortic regurgitation (RR, 22.4 [CI, 2.72 to 184.8]) were positively associated with embolism. For patients in atrial fibrillation, previous embolism (RR, 3.11 [CI, 1.66 to 5.85]) was positively associated with embolism; percutaneous balloon mitral commissurotomy (RR, 0.37 [CI, 0.18 to 0.79]) was a negative predictor. CONCLUSIONS: It may be prudent to give anticoagulants not only to patients in atrial fibrillation and patients with previous systemic embolism but also to those showing a left atrial thrombus or significant aortic regurgitation on echocardiography. Early percutaneous balloon mitral commissurotomy may also help prevent systemic embolism in patients with mitral stenosis.     

Characterization of Ultrathin Dielectric Films With the Prism-Coupler Method

We demonstrate a technique of applying the prism-coupler method to the characterization of dielectric films that are too thin to support enough guided modes in air for the normal application of the method. The technique is based on applying suitable index-matching liquids on the surface of the thin film to increase the number of effective indexes available for the determination of the refractive index and the thickness of the film. With this technique, even thin films that do not support any guided modes in air can be characterized. We apply the technique to the characterization of polymer thin films as thin as 100-200 nm and discuss its performance and limitation     

Pharmacokinetic and pharmacodynamic evaluation of the potential drug interaction between venlafaxine and ethanol

Venlafaxine is a new antidepressant with a unique mode of action. Because many patients taking antidepressant therapy may self-medicate with ethanol, this study was undertaken to assess the possible pharmacokinetic and pharmacodynamic interactions between venlafaxine and ethanol. This randomized, double-blind, placebo-controlled, two-period crossover study was conducted with 16 healthy men. Multiple doses of venlafaxine (50 mg every 8 hours) or placebo were administered for 7 days. On days 5 and 7 a single dose of 0.5 g/kg of ethanol or a placebo solution was administered in a randomized fashion. Pharmacokinetic data indicated that ethanol administration did not affect the disposition of venlafaxine or O-desmethylvenlafaxine. Similarly, venlafaxine administration did not affect the pharmacokinetic disposition of ethanol. Ethanol produced its expected effects on the eight psychometric tests administered. Venlafaxine produced small effects on the results of the Digit Symbol Substitution Test, the Divided Attention Reaction Time, and the Profile of Mood States. No pharmacodynamic interaction was detected between venlafaxine and ethanol.     

Characterization of a peptide analog of a determinant of type II collagen that suppresses collagen-induced arthritis

Immunization of susceptible strains of mice with type II collagen (CII) elicits an autoimmune arthritis known as collagen-induced arthritis (CIA). One analogue peptide of the immunodominant T cell determinant, A9 (CII245-270 (I260-->A, A261-->B, F263-->N)), was previously shown to induce a profound suppression of CIA when coadministered at the time of immunization with CII. In the present study, A9 peptide was administered i.p., orally, intranasally, or i.v. 2 to 4 wk following CII immunization. We found that arthritis was significantly suppressed even when A9 was administered after disease was induced. To determine the mechanism of action of A9, cytokine responses to A9 and wild-type peptide A2 by CII-sensitized spleen cells were compared. An increase in IL-4 and IL-10, but not in IFN-gamma, was found in A9 culture supernatants. Additionally, cells obtained from A9-immunized mice produced higher amounts of IL-4 and IL-10 when cultured with CII compared with cells obtained from mice immunized with A2, which produced predominantly IFN-gamma. Suppression of arthritis could be transferred to naive mice using A9-immune splenocytes. Lastly, phosphorylation of TCRzeta was not altered in the immunoprecipitates from the lysates of cells exposed to analogue peptides (A9 and A10) together with wild-type A2 in a T cell line and two I-Aq-restricted, CII-specific T hybridomas. We conclude that analogue peptide A9 is effective in suppressing established CIA by inducing T cells to produce a Th2 cytokine pattern in response to CII.     

Low-speed tack measurements of fluids and inks

Low-speed tack measurements (≈ 0.1–6.0 rad/s or ≈ 1–57 RPM) have been determined for polymeric-based solution inks and oil-based dispersion inks, tripropylene glycol (TPG), Igepal (I-530), and N-350 (viscosity calibration standard) fluids using a metal roller/incline method. The inks and fluids were tested under “unaged” or reference conditions at 25°C. The inks were “aged” at 70°C and, subsequently, tack measurements were made at 25°C. The tack (T_i) and angular speed (W_i) for the inks were empirically fitted as functions of incline angle (α) and “aged” time, t_cd. A correlation was also made for tack and percent weight change, ΔW_i. Other factors, such as viscosity, surface tension, humidity, and “aging” temperature, T_cd, were also found to affect the magnitude and variation of tack. Additionally, the results suggest that low-speed tack measurements are quite useful for selecting solution inks containing polymeric substances that possess the desirable spreading, mixing, and pressing properties in high-speed/high-volume printing and the component compatibility necessary for long-term performance. © 1995 John Wiley & Sons, Inc.     

Image formation of alkyl-pendent aromatic polyimide by photocoupling with aromatic ketones

Positive and negative photostructures are formed after the polyimide (PI) of 4,4′-biphthalic anhydride (BPA) and 4,4′-diamino-3,3′-dimethyldiphenylmethane (DADMDPM), PI(BPA/DADMDPM) is doped with Michler′s ketone (MK) and benzophenone (BP), respectively, and is subjected to UV light (400 ± 50 nm) irradiation and solvent development. The principle of positive feature formation is based on the photocoupling of MK with PI, which increases PI solubility and thus enables a positive pattern to be developed. The phenomenon of negative photopatterning results from intermacromolecular H-bonding between the carbonyl group of the imide ring and the hydroxy group which is formed in the photoinduced coupling reaction between BP and PI. Lithographic evaluation shows that the MK-doped positive-acting PI film cannot form useful patterns because UV wavelengths are strongly absorbed by MK, which limits the depth of photocoupling in the film. On the other hand, 2-μm-wide lines can be resolved in the BP-doped negative-acting 0.6-μm-thick PI film.     

Partial eigenstructure assignment and its application to largescale systems

The notion of partial eigenstructure assignment (PEA) via linear state feedback control in linear multivariable systems is introduced. This notion is a natural extension of eigenstructure assignment and partial eigenvalue assignment. Some theoretical basis for PEA is provided, and a parametric expression for feedback gain matrices achieving PEA is derived. An effective numerical algorithm for PEA tailored to large-scale systems is presented. As an extension of the algorithm, a recursive algorithm for eigenstructure assignment is presented. These algorithms possess the following desired properties: (1) compared to existing methods, the presented algorithms significantly reduce the required computation time via transforming high-dimensional matrix computations into low-dimensional matrix computations; (2) they can be implemented in a parallel fashion. The proposed algorithm for PEA is applied to modal control of large flexible space structure systems     

Grain-Boundary Migration in Nonstoichiometric Solid Solutions of Magnesium Aluminate Spinel: II, Effects of Grain-Boundary Nonstoichiometry

The grain-boundary chemistry of magnesium aluminate spinel solid solutions MgO· n Al₂O₃ in which grain growth measurements were reported in part I has been investigated in order to understand the mechanism of grain-boundary migration. It is found that although segregation of impurity Ca and Si is common, much larger deviations in grain-boundary stoichiometry are present. There is an excess of Al and O relative to Mg at grain boundaries in all compositions. Grain-boundary migration appears to be rate-limited by solute drag from intrinsic defects accommodating lattice nonstoichiometry, rather than by extrinsic solutes, consistent with the observed impurity tolerance of grain-boundary mobility. Different rate-limiting defects are proposed for magnesia-rich and alumina-rich spinels.