Measurement of chemical emission rates from cigarette butts into air

This study examined airborne emissions from cigarette butts for styrene, 2-methyl-2-cyclopenten-1-one, naphthalene, triacetin, and nicotine. Ten experiments were conducted by placing butts in a stainless steel chamber and measuring the chemical concentrations in chamber air. Emission rates were determined from the concentrations. Triacetin and nicotine concentrations were roughly 50% of initial concentrations after 100 hours, while concentrations of other chemicals decayed to less than 10% of initial concentrations within 24 hours. Initial emission rates per cigarette butt ranged from 200 to 3500 ng h⁻¹. Triacetin and nicotine emission rates at 25°C were 1.6 to 2.2 times higher than the rates at 20°C, while the emission rates of other chemicals at 25°C were 1.1 to 1.3 times higher than the rates at 20°C only during the first sampling period. The chemical concentrations and emission rates at 30°C were comparable or lower than the values at 25°C, possibly due to different batches of cigarettes used. The 24-hours emitted mass of nicotine from a cigarette butt at 25°C could be up to 14% of the literature reported nicotine masses emitted from a burning cigarette.     

The Oregon Land Use Act Implications for Farmland and Open Space Protection

In 1973, Oregon adopted a statewide comprehensive land use management program. It represents an important new approach in land use control and merits careful consideration and examination by land use analysts, policy makers, and the public. By providing statewide standards for land use planning and implementation carried out through an ongoing local administrative process, an important state land use management role has been established and, many argue, without a substantial erosion of local flexibility.

Rural land use management, particularly farmland protection, is an important component of the Oregon program. The combination of state mandated, locally implemented urban growth boundary designations and exclusive farm use zoning represents a unique case in farmland protection policy. The performance of the program is evaluated, and economic trade-offs in the selection of minimum lot size standards are discussed. This program offers the promise of substantially improving rural land use management in Oregon at a modest cost to the public sector.     

Radiation exposure assessment for portsmouth naval shipyard health studies

Occupational radiation exposures of 13,475 civilian nuclear shipyard workers were investigated as part of a retrospective mortality study. Estimates of annual, cumulative and collective doses were tabulated for future dose-response analysis. Record sets were assembled and amended through range checks, examination of distributions and inspection. Methods were developed to adjust for administrative overestimates and dose from previous employment. Uncertainties from doses below the recording threshold were estimated. Low-dose protracted radiation exposures from submarine overhaul and repair predominated. Cumulative doses are best approximated by a hybrid log-normal distribution with arithmetic mean and median values of 20.59 and 3.24 mSv, respectively. The distribution is highly skewed with more than half the workers having cumulative doses <10 mSv and >95% having doses <100 mSv. The maximum cumulative dose is estimated at 649.39 mSv from 15 person-years of exposure. The collective dose was 277.42 person-Sv with 96.8% attributed to employment at Portsmouth Naval Shipyard.     

A comparison of statistical methods for estimation of less than detectable ionising radiation exposures

Methods were developed to estimate the ionising radiation dose below the detection level (DL) of personal monitoring devices for a case-control study of protracted radiation exposure and lung cancer. Exposure data were grouped by dosemeter type and monitoring period. Each group contained dosimetry data that were interval-censored from limitations in measurement precision and included left-censoring of observations below detection. The grouped data were fit to a three parameter hybrid-lognormal distribution by maximum likelihood estimation. Using the fitted distribution, bootstrap samples were either simulated by Monte Carlo or constructed by sampling with replacement. The resulting bootstrap sample distributions were then used to predict the missing dose values and the associated uncertainty in the estimate. Among study subjects, 1357 workers were monitored with film dosimetry. Among the 39,263 dose observations 20,416 were recorded as zero dose, indicating 52% left-censoring. The statistical methods estimated 0.31 person-Sv below the DL or approximately 1% of the total collective dose for this study population.     

Influence of the preparation procedure and chitosan type on physicochemical properties and release behavior of alginate–chitosan microparticles

Background: The potential for use of chitosan-treated alginate microparticles as a vehicle for oral phenytoin delivery has not been thoroughly exploited. Aim: We studied the influence of preparation procedure and chitosan type on physicochemical properties and release behavior of alginate-chitosan microparticles. Method: The total number of 24 microparticles formulations prepared by varying contents of calcium gelling ions and varying contents and type of chitosan was examined. As an additional variable, two different hardening times (1 and 24 hours) were employed. Possible interactions of components, surface morphology of microparticles as well as release profile of phenytoin were studied. Results: Both series of formulations with regard to hardening times, irrespective of the chitosan type and/or concentration employed appeared to be highly loaded with the model drug (above 90%). The drug release studies showed that the kinetics of phenytoin cannot be straightforwardly predicted based on the molecular weight of chitosan alone. On the other hand, prolonging the hardening time from 1 to 24 hours had significantly improved phenytoin kinetics, and gave rise to a formulation with the liberation half-time of about 2.5 hours. Conclusion: This study showed that the latter formulation is eligible for further modifications aimed at improving the regularity of phenytoin absorption.     

Reference range and repeatability of a combined intestinal permeability and function test in clinically healthy Irish setter dogs

We investigated the influence of nutrition and exercise interventions within cognitive/behavioral and public health formats on weight and blood lipid profiles in obese children. Compliance was also examined as well as the relationship of the compliance measures with clinical outcome variables. Three conditions were compared over 16 sessions: nutrition and eating-habit change followed by exercise (NE), exercise followed by nutrition and eating-habit change (EN), and an information control (INFO). NE and EN were presented in a cognitive/ behavioral framework which focused on the development of self-regulation whereas the INFO condition received the same material in a public health/educational model. NE and EN participants evidenced modest, yet significant, reductions in weight and blood lipids, and the impact of these two interventions endured at a five-year follow-up. In contrast, INFO participants displayed stable weight and blood lipids during the course of the program, and most remained morbidly obese at follow-up. Improved nutrition, increased physical activity and fitness were significantly correlated with weight and lipid reductions.     

Cardiac rupture with dobutamine stress echocardiography

Dobutamine stress echocardiography is a safe method for the evaluation of coronary artery disease, myocardial function, and viability. The potential for cardiac rupture exists. Although clinical and electrocardiographic criteria may be helpful in identifying those patients at risk for cardiac rupture, the criteria are neither sensitive nor specific enough to exclude patients or make recommendations regarding which patients should undergo dobutamine stress echocardiography in the post-infarction period. Physicians must be aware of the possibility and be prepared to treat cardiac rupture when performing dobutamine stress echocardiography.     

Choosing input indicators for research managers

This paper focusses on the use of input indicators as a planning tool for research planners and administrators in one research sector. It reviews the experience of a number of developing countries in attempting to develop such indicators for national agricultural research systems. It appears that the more commonality there is in the research subject and environment, the more disaggregated the input data, research managers would find useful. While the paper reviews only one research sector, it concludes with comments on the feasibility of using similar measures in other sectors.The views expressed in this paper are those of the author and do not necessarily represent the views of the International Development Research Centre.