Coffee, Alcohol, Smoking, Physical Activity and QT Interval Duration: Results from the Third National Health and Nutrition Examination Survey

Abnormalities in the electrocardiographic QT interval duration have been associated with an increased risk of ventricular arrhythmias and sudden cardiac death. However, there is substantial uncertainty about the effect of modifiable factors such as coffee intake, cigarette smoking, alcohol consumption, and physical activity on QT interval duration.We studied 7795 men and women from the Third National Health and Nutrition Survey (NHANES III, 1988-1994). Baseline QT interval was measured from the standard 12-lead electrocardiogram. Coffee and tea intake, alcohol consumption, leisure-time physical activities over the past month, and lifetime smoking habits were determined using validated questionnaires during the home interview.In the fully adjusted model, the average differences in QT interval comparing participants drinking ≥6 cups/day to those who did not drink any were -1.2 ms (95% CI -4.4 to 2.0) for coffee, and -2.0 ms (-11.2 to 7.3) for tea, respectively. The average differences in QT interval duration comparing current to never smokers was 1.2 ms (-0.6 to 2.9) while the average difference in QT interval duration comparing participants drinking ≥7 drinks/week to non-drinkers was 1.8 ms (-0.5 to 4.0). The age, race/ethnicity, and RR-interval adjusted differences in average QT interval duration comparing men with binge drinking episodes to non-drinkers or drinkers without binge drinking were 2.8 ms (0.4 to 5.3) and 4.0 ms (1.6 to 6.4), respectively. The corresponding differences in women were 1.1 (-2.9 to 5.2) and 1.7 ms (-2.3 to 5.7). Finally, the average differences in QT interval comparing the highest vs. the lowest categories of total physical activity was -0.8 ms (-3.0 to 1.4).Binge drinking was associated with longer QT interval in men but not in women. QT interval duration was not associated with other modifiable factors including coffee and tea intake, smoking, and physical activity

COMPUTER-FOCUSING FOR AREA SCANS

Scintillation area scanning is a relatively new diag nostic method in clinical medicine and its use has progressed rapidly over the years. Because the method is used to visualize the spatial distribution of radioactivity in internal organs, one would like to be able to detect and display the smallest possible lesions. Many methods using a wide range of in struments and radiopharmaceuticals have been advo cated to increase the resolving power of the scanner. At the present time, however, the resolution of area scanners is not sufficiently sharp. A multichan nel focusing collimator consisting of a honeycomb of hexagonal holes is usually used, but even with this focusing collimator the region of response is broad and has a circular cross section at the focal distance. The sensitivity in scanning must also be increased, but at present this can be achieved only by sacrificing spatial resolution. In a previous paper (/) we reported that a correc tion method based on iterative approximation which had been used to correct distortion in beta and gamma spectra (2) could be used to extract true information from the observed data; with this method corrected profiles obtained with a wholebody linear scanner showed a more detailed struc ture than did the original. We felt that a similar correction method could be used in the image of area scans. At present a wide variety of analog techniques are used to record area-scanning data. These analog techniques, however, appear to offer less accurate recording and result in a loss of information. More over, they are not adaptable to computer analysis. To use digital-computer processing, it is necessary to use digital recording in which all original information in an unmodified form is collected and recorded as an array of actual numbers. The purpose of this paper is to show how digital information suitable for computer processing can be used and how more information can be obtained from computer-corrected area scans than from the original digital scan or conventional analog data presentation. METHODS The data-collection system consisted of a commer cial scanner with a Nal(Tl) crystal, 2 in. in diam eter and 2 in. thick, and a 19-hexagonal-hole honeycomb collimator. Pulses from a single-channel pulse-height analyser were fed into a 128-channel multichannel analyser used in the multiscaling mode. Because a bidimensional multiscaler was not avail able, the single-dimensional 128-channel multiscaler was used to present a numerical profile for each scan sweep. One-way scanning was done at a speed of 2.7 mm/sec, and 1-mm spacing was selected. The pre set counting time in each channel of the multiscaler was 0.38 sec. Consequently each channel corre sponded to the accumulation of counts from a length of 1 mm of scan sweep at the scanning speed se lected. The recording of the counts for each sweep was started just when the reference point of the de tector passed over the scan registration line which met the scan sweep direction at right angles in order to include precise positional information. After each scan sweep, the counts accumulated in each of the 128 channels were printed with a Hewlett Packard fast printer. During the printing the detector returned to the next starting point but spaced 1 mm perpen dicular to the sweep direction. Then the multiscaler started to accumulate counts for the next scan sweep. A channel number corresponded to the position of the detector in each scan sweep, and the number of the sweep corresponded to the position in the space direction. Thus to provide a two-dimensional array of numbers representing area scanning data

STILBENOID CONSTITUENTS IN WELWITSCHIA MIRABILIS

Welwitschia mirabilis is an endangered and unique gymnosperm of the Namibian Desert of South West Africa. It is a monotypic member of the Genus Welwitschia. Since its discovery about 140 years ago, very little is known about its chemical constituents. In the present study we report the isolation and structure elucidation of 10 new stilbenoids from the stem and root of the plant along with some known compounds. The structures of the compounds were assigned by spectroscopic analysi

Size distributions of polycyclic aromatic hydrocarbons in urban atmosphere: sorption mechanism and source contributions to respiratory deposition

Current knowledge on atmospheric particle-phase polycyclic aromatic hydrocarbons (PAHs) size distribution remains incomplete. Information is missing on sorption mechanisms and the influence of the PAHs' sources on their transport in human respiratory system. Here we present the studies systematically investigating the modal distribution characteristics of the size-fractioned PAHs and calculating the source contribution to adverse health effects through inhalation. Aerosol samples with nine size fractions were collected from Shanghai urban air over one year period 2012–2013. A high correlation coefficient existed between measured and predicted values (<i>R</i>²= 0.87), indicated that the data worked very well in current study. Most PAHs were observed on the small particles followed with seasonality differences. When normalized by PAHs across particle diameters, the size distribution of PAHs exhibited bimodal patterns, with a peak (0.4–2.1 &mu;m) in fine mode and another peak (3.3–9.0 &mu;m) in coarse mode, respectively. Along with the increasing ring number of PAHs, the intensity of the fine mode peak increased, while coarse mode peak decreased. Plotting of log(PAH/PM) against log(<i>D</i>_<i>p</i>) showed that all slope values were above −1 with the increase towards less-ring PAHs, suggesting that multiple mechanisms, i.e. adsorption and absorption controlled the PAHs on particles, but adsorption played a much stronger role for 5- and 6-ring than 3- and 4-ring PAHs. The mode distribution behavior of PAHs showed that fine particles were major carriers for the more-ring PAHs. Further calculations using inhaling PAHs data showed the total deposition fluxes in respiratory tract were 8.8 ± 2.0 ng h^-1. Specifically, fine particles contributed 10–40 % of PAHs deposition fluxes to the alveolar region, while coarse particles contributed 80–95 % of ones to the head region. Estimated lifetime cancer risk (LCR) for people exercised in haze days (1.5 &times; 10^-6) was bigger than the cancer risk guideline value (10^-6). The largest PAHs contribution for LCR mainly came from the accumulation particles. Based on source apportionment results generated by positive matrix factorization (PMF), it was found that the cancer risk caused in accumulated mode mainly resulted from biomass burning (24 %), coal combustion (25 %) and vehicular emission (27 %). The present results contribute to a mechanistic understanding of PAHs size distribution causing adverse health effects and will help develop some source control strategies or policies by relying on respiratory assessment data