- Détails du magazine
- Première publication
- 01 Jan 1992
- Période de publication
- 4 fois par an
- Accès libre
Pages: 205 - 209
The presence of dioxin-like compounds, such as chlorinated dibenzodioxins, chlorinated dibenzofurans and chlorinated biphenyls, in mainstream cigarette smoke has been investigated for seven cigarette brands covering a range of ‘tar’ deliveries from 1 mg to 14 mg. Adjusted per milligram of total particulate matter (TPM), ultra-light cigarettes had the highest concentrations of toxic equivalents (TEQ) of 10 fg/mg TPM. As the ‘tar’ delivery increased, lower concentration values were found in lights and full-flavor cigarettes. Calculated on the basis of a pack of twenty cigarettes, mainstream smoke from the ultra-lights and lights products produced values around 200 fg TEQ, and the full-flavor brand produced 575 fg TEQ per pack. Levels of TEQ from dioxin-like compounds in the tobacco section of four cigarette brands did not show significant differences and were similar to previous literature findings.
- Accès libre
Pages: 211 - 215
A robust method for the analysis of selected vapour phase (VP) compounds in mainstream smoke (MSS) is described. Cigarettes are smoked on a rotary smoking machine and the VP that passes through the Cambridge filter pad collected in a TedlarA¯ bag. On completion of smoking, the bag contents are sampled onto an adsorption tube containing a mixed carbon bed. The tube is subsequently analysed on an automated thermal desorption (TD) system coupled to a gas chromatography-flame ionization detector (GC-FID) using a PoraPLOT-Q column. Quantification of 14 volatile compounds including the major carbonyls is achieved. Details of the method validation data are included in this paper. This method has been used to analyse the VP of cigarette MSS over a wide range of ‘tar’ deliveries and configurations with excellent repeatability. Results for the University of Kentucky reference cigarette 1R4F are in good agreement with reported values.
- Accès libre
Pages: 216 - 222
In order to clarify the mechanism for the generation of cigarette smoke, the combustion mechanism of a burning cigarette during a puff was investigated by focusing on air transfer. In particular, the air flow distribution outside a burning cigarette was observed and related to the aerodynamic effects of the cigarette paper and the puffing rate. The air flow rate was measured by Particle Image Velocimetry (PIV), using olive oil droplets as the tracer particles. It was found that air does not flow into the tip of the burning cigarette and that the air flow was concentrated at the region -2 to 2 mm around the cigarette paper char-line. This behavior was independent of the cigarette paper basis weight. When the puffing rate was changed from 2.5 to 35 mL/s, the air flow was concentrated at a region close to the cigarette paper char-line and the maximum velocity around the cigarette paper char-line increased with the puffing rate.
- Accès libre
Effect of Water Regime and Nitrogen Fertilisation on Growth Dynamics, Water Status and Yield of Burley Tobacco ( Nicotianatabacum L.)
Pages: 223 - 233
The results of a two-year research project into burley tobacco are reported and discussed. Three irrigation levels (40, 80 and 120% restitution of evapotranspiration (ET)) were factorially combined with four levels of nitrogen fertilisation (0, 80, 160 and 240 kg ha). Leaf area, leaf and stem dry matter and root development were measured. We monitored the water status of the 0-90 cm soil layer, the plants and stomatal resistance. Relations were also studied between leaf turgor pressure and plant growth, between the irrigation regime and plant water status, and between root and shoot development. Finally, water use efficiency (WUE) and quality and quantity of cured leaves yields were evaluated. Nitrogen fertilisation did not affect plant water status, although it promoted plant growth, both in terms of leaf area and leaf and stem dry matter, and induced a yield increase in quantity and quality. Our trial showed little interaction between nitrogen fertilization level and water regime. Under such agronomic condition, the margins for increasing plant growth with nitrogen fertilization are limited, which is why application of nitrogen rates in excess of 160 kg haappear inadvisable. The difference in irrigation volumes led to a different soil water content which affected plant water status, stomatal functioning, plant growth, both in the roots and shoots, yield and quality of the cured leaves. The latter did not vary with the increase in water volume, while yield increased. Water use efficiency increased as the irrigation volume decreased and varied during the cropping cycle, increasing until early bloom, then decreasing. Relations between leaf turgor pressure and plant growth highlighted the different response of plants subjected to water stress compared with non-stressed plants.
- Accès libre
Agronomic Performance of Flue-Cured Tobacco F1 Hybrids Obtained with Different Sources of Male Sterile Cytoplasm
Pages: 235 - 239
Four cytoplasmic male sterile (cms) F1flue-cured hybrids cv. Wiaelica × cv. Virginia Golta (VG), the male fertile analogue and the parental varieties were tested at two locations in Poland in a replicated field trial. The cms sources in the hybrids were
- Accès libre
The Effect of Inhalation Volume and Breath-Hold Duration on the Retention of Nicotine and Solanesol in the Human Respiratory Tract and on Subsequent Plasma Nicotine Concentrations During Cigarette Smoking
Pages: 240 - 249
The influence of inhalation depth and breath-hold duration on the retention of nicotine and solanesol in the human respiratory tract and on nicotine uptake was studied in ten cigarette smokers. In a first series of experiments, the subjects took seven puffs from a 10 mg ‘tar’ yield, test cigarette and a fixed volume of air (0, 75, 250, 500 or 1000 mL, as required by the protocol) was inhaled after each puff in order to give a controlled ‘depth’ of inhalation. The inhalation was drawn from a bag containing the required volume of air. Following a 2 s breath-hold, subjects exhaled normally, with the first exhalation after each puff passing through a single acidified filter pad for collection of the non-retained nicotine and solanesol. Blood samples were taken before and at intervals during and after smoking for the sessions with 0, 75 and 500 mL inhalation volumes for determination of plasma nicotine and carboxyhaemoglobin levels. Another series of experiments was conducted with a fixed inhalation volume (500 mL) and two further breath-hold durations (0 and 10 s) in addition to 2 s from above. Nicotine and solanesol retentions were measured for each breath-hold condition. The amounts of nicotine retained within the respiratory system, expressed as a percentage of the amount taken into the mouth, were consistently higher than the corresponding values for solanesol in all five inhalation conditions (0-1000 mL, 2 s breath-hold). Nicotine retention increased from 46.5% at zero inhalation to 99.5% at 1000 mL inhalation (2 s breath-hold) and from 98.0% at zero breath-hold to 99.9% at 10 s breath-hold (500 mL inhalation). Solanesol retention increased from 34.2% at zero inhalation volume to 71.9% at 1000 mL inhalation (2 s breath-hold) and from 51.8% at zero breath-hold to 87.6% at 10 s breath-hold (500 mL inhalation). Plasma nicotine decreased from pre-smoking levels after zero inhalation indicating that the nicotine retained within the mouth was poorly absorbed into the systemic circulation. After 75 mL inhalation, plasma nicotine levels were significantly greater than for zero inhalation but not significantly less than after 500 mL inhalation except at the time of maximum nicotine concentration. As in every experimental condition, a higher percentage of nicotine than solanesol was retained within the respiratory tract, it was concluded that the difference in retention of the moderately volatile nicotine and the non-volatile solanesol is consistent with the concept of nicotine evaporation from smoke particles and the subsequent efficient retention in the airways of gaseous nicotine. The retention of solanesol followed the expected pattern of particulate deposition i.e., an increase with both increasing depth of inhalation and breath-hold duration. However, nicotine retention was almost complete even at shallow inhalations and short breath-hold durations.
- Accès libre
Pages: 250 - 250
The Smoking Behaviour Sub Group of the Cooperation Centre for Scientific Research Relative to Tobacco (CORESTA) was set up in 1996 with the aims of reviewing information relevant to smoking behaviour, publishing the reviews, identifying gaps in information and suggesting suitable studies. So far three reviews have been published by members of the sub group (1-3) and other reviews are in progress. One aspect of the subject that has become apparent to the sub group is that terms are used inconsistently in various papers on smoking behaviour. We therefore propose that the following terms and their definitions are used in the future.