bluuebunny/crossref_metadata_2025_split huggingface dataset:
The Composition of Cigarette Smoke: Problems with Lists of Tumorigens
Authors: Rodgman A 
Published: July 2016

Abstract
Since the mid-1960s, various investigators, agencies, and institutions have disseminated lists of cigarette mainstream smoke (MSS) components reported to be tumorigenic on the basis of laboratory bioassays conducted under conditions significantly different from those encountered by the smoker during exposure to the components in the cigarette MSS aerosol. Since 1990, numerous lists of cigarette MSS components, defined as significant tumorigens, have been compiled by American Health Foundation personnel, Occupational Safety and Health Administration (OSHA), Fowles and Bates, and R.J. Reynolds R&D personnel. The purpose of most of the reports was to define human risk assessment and to dissuade smokers from smoking. Various investigators and agencies have frequently cited the earlier and/or the more recent lists of tumorigenic entities. The recent compilations, involving nearly 80 MSS components, suffer from serious deficiencies including: a) Use of per cigarette delivery ranges for specified components which often include analytical data from cigarettes manufactured in the 1950s and 1960s which are not comparable to lower-'tar’ yield cigarettes manufactured since the mid-1970s. b) Absence of standard analytical procedures for most of the listed components. c) Methodological considerations regarding bioassays used to determine tumorigenicity of the listed MSS components. d) Difficulty in extrapolating in vivo bioassay data obtained by non-inhalation modes of administration of a single compound to the human smoking situation involving inhalation of a complex aerosol containing that compound. e) Inhalation data inadequacies regarding the tumorigenicity of many of the components. f) Several tobacco smoke components are listed despite the fact their presence has not been confirmed, their MSS level has not been defined, or their MSS level is no longer relevant. g) Insufficient consideration of inhibitors of tumorigenesis and mutagenesis found in MSS. h) Difficulty in extrapolation of inhibition/anticarcinogenesis/antimutagenesis observed in a one-on-one in vivo situation to the complex MSS aerosol situation. j) Alternate exposures to many of the listed smoke components. k) Discrepancies among the lists. l) Discrepancies within the lists.A more appropriate use of the listing process is the identification of potential chemical targets for removal from, or inhibition in cigarette MSS.
Role of Oxides of Nitrogen in Tobacco-Specific Nitrosamine Formation in Flue-Cured Tobacco
Authors: Nestor TB , Gentry JS , Riddick MG , Conner BT , Peele DM , Edwards ME 
Published: July 2016

Abstract
Tobacco is known to contain a class of nitrosamines known as tobacco-specific nitrosamines or TSNA. Nitrosation of naturally occurring tobacco alkaloids is commonly accepted as the mechanism of TSNA formation in tobacco. Because green and freshly harvested tobaccos are virtually free of TSNA, formation and accumulation of TSNA are generally considered to occur during the curing process. Most recent hypotheses have focused on microbial reduction of nitrate to nitrite and other oxides of nitrogen (NOcompounds) that react with tobacco alkaloids to form TSNA during curing. This natural microbial process remains the prevalent hypothesis for TSNA formation in burley and other air-cured tobaccos. However, a different mechanism for the formation of TSNA in flue-cured tobacco, independent of microbial activity, is documented in this paper. It is common practice to flue-cure Virginia or blonde tobacco in bulk barns that incorporate forced air ventilation and temperature control. For the last thirty-five years, many modern bulk barns in North America generally have used liquid propane gas (LPG) with direct-fired burners that exhaust combustion gases directly into the barn where the tobacco is exposed to those gases. Our studies indicate that LPG combustion by-products in the exhaust stream, namely NO, react with naturally occurring tobacco alkaloids to form TSNA. Heat exchange curing methods preclude exposure of the tobacco to combustion gases and by-products, thereby eliminating this significant source of TSNA formation, without degrading leaf quality or smoking character. Research findings from 1998 and 1999 are presented to demonstrate the role of NOgases in TSNA formation and the significance of direct-fired curing as a primary source of TSNA formation in flue-cured tobacco. Also, data from an extensive barn conversion program in 2000, which resulted in a 94% average reduction in TSNA levels in cured flue-cured leaf, are presented.
Application of Nanoparticle Iron Oxide in Cigarette for Simultaneous CO and NO Removal in the Mainstream Smoke
Authors: Li P , Rasouli F , Hajaligol MR 
Published: July 2016

Abstract
Based on the unique temperature and oxygen profiles in a burning cigarette, a novel approach is proposed in this paper to use a single oxidant/catalyst in the cigarette filler for simultaneous removal of carbon monoxide (CO) and nitric oxide (NO) in mainstream smoke. A nanoparticle iron oxide is identified as a very active material for this application due to its multiple functions as a CO catalyst, as a CO oxidant, and in its reduced forms as a NO catalyst. The multiple functions of the nanoparticle iron oxide are characterized in a flow tube reactor and the working mechanisms of these multiple functions for CO and NO removal in a burning cigarette are explained. The effect of smoke condensate on the catalyst are examined and discussed. The advantage of in situ generation of the catalyst during the cigarette burning process is illustrated. The test results of nanoparticle iron oxide for CO and NO removal in cigarettes are presented.
Diffusion of Moisture in a Cigarette Tobacco Column at Room Conditions
Authors: Oh IH , Jheong GR 
Published: July 2016

Abstract
The moisture content of cigarettes has a significant impact on the shelf life and the taste of the products as well as various physical properties of cigarettes including loose ends, burning rate, hardness, and pressure drop. To prepare better products it would be helpful to develop proper mathematical models for the simulation of moisture diffusion characteristic dynamics in a cigarette. In this work, four mathematical models have been developed with appropriate assumptions adequate to analyze the dynamics of moisture diffusion in cigarettes. The simulation of the derived models was also carried out in this work. When the theoretical values produced from each model were compared with the corresponding experimental data, it was found that three models (I-II, II, III) can be used to explain the behavior of moisture in cigarettes. Convective mass transfer coefficients and effective moisture diffusivities that fit best were obtained by a regression analysis of the model using the experimental values. The simulation of the models revealed that there is no significant positional dependence of moisture content inside a tobacco column because most of the moisture dries out radially through the cigarette wrapper. The drying rate of moisture in a tobacco column is rarely affected by effective moisture diffusivity, but strongly influenced by convective mass transfer. To prevent quality deterioration of the cigarettes during long-term storage, it is concluded that improvement of the cigarette wrapper and air tightness of the package, which are directly related to the convective mass transfer, is very important.
Analysis of Sidestream Smoke VOCs and Characterization of their Odor Profiles by VOC Preconcentrator-GC-O Techniques
Authors: Higashi N , Shikata H , Shimoda M , Hayakawa I 
Published: July 2016

Abstract
Various techniques have been employed in the analysis of volatile organic compounds (VOCs). However, these techniques are insufficient for the precise analysis of tobacco smoke VOCs because of the complexity of the operating system, system instability, or poor sensitivity. To overcome these problems, a combined system of VOC preconcentrator, gas chromatograph, and olfactometer has been developed. The performance of this new system was evaluated in the analysis of VOCs in tobacco smoke and applied to the odor profiling of sidestream smoke (SSS) that has not been sufficiently investigated in the past.
A VOC sample in a gas-sampling bag was injected into a gas chromatograph through a preconcentrator, where it was concentrated, dehydrated, and cryo-focused. Separated VOCs were introduced into a mass spectrometer (for qualitative and quantitative analysis) and a sniffing port (for odor profiling) by a splitting device. In addition to the conventional Gas Chromatography-Olfactometry (GC-O) technique that was used for describing the odor quality of each compound, the odor intensity was estimated based on the dilution ratio of the sample, Aroma Direct Dilution Analysis (ADDA). Also, the contribution of each VOC to the overall SSS odor was estimated by sensory evaluation.
This system permitted adequate characterization of the VOCs. The reproducibility of quantification was also good enough with Coefficient of Variation (CV) values less than about 5% (n = 5). With the GC-O technique, we obtained an SSS odor profile composed of over 30 odorants. ADDA indicated that seven odorants were sufficient to characterize SSS odor. In addition, the omit-test revealed that three odor attributes, (‘metallic’, ‘potato-like’, and ‘popcorn-like’) were most important for the characterization of SSS odor.
The UK Smoke Constituents Testing Study. Summary of Results and Comparison with Other Studies
Authors: Gregg E , Hill C , Hollywood M , Kearney M , McLaughlin D , McAdam K , Williams M , Purkis S 
Published: July 2016

Abstract
At the request of the UK Department of Health, samples of 25 commercial UK cigarette brands were provided to LGC Ltd a for smoke analysis. The brands reflected a high market share (58% in July 2001) and included a wide range of blend and product styles manufactured and imported into the UK.= 0.76), suggesting a minor role of other design features on constituents yield variability. This was confirmed by the application of multiple regression analysis to the data. A subset of five brands, retested at another laboratory, gave between-laboratory differences in mean constituent yields of as much as 2.5-fold. Consideration of these results, other likely sources of analytical variation in this study and a review of other studies, clearly indicates that any tolerance values to be associated with individual smoke constituent measurements will be greater than those for NFDPM, and in some cases, much greater. Consistent with the reported results from other large studies it is concluded that, under ISO smoking conditions, smoke constituent yields are largely predictable, if NFDPM and CO yields are known, for a standard cigarette. Given these observations and the likely limitations of analytical determination, the need for routine measurement of smoke constituent yields, other than NFDPM, nicotine or CO, on standard cigarettes, is questionable.
An Experimental and Numerical Analysis of Puff Hydrodynamics
Authors: Saidi MS , Hajaligol MR , Rasouli F 
Published: July 2016

Abstract
The permeability of a tobacco rod in a cigarette increases as it converts into char and ash in the coal. The hot coal introduces a significant resistance to the air flow when air passes through. Through a series of experiments, the cigarette burn line and burn rate, the centerline temperature, and the pressure drop were measured for continuous puffing conditions. The gas viscosity was calculated from the temperature distribution inside the cigarette and applying Sutherland's law. Then, the experimental setup was mathematically modeled from a commercially available CFD (Computational Fluid Dynamics) code and, by matching the numerical and experimental results, the changes in coal and filter permeability during puffing were estimated. The numerical simulation successfully reproduced the results of experiments on the air flow through the coal, ventilation holes and paper wrapper.
Measurement of Air Flow Outside a Burning Cigarette during a Puff using Particle Image Velocimetry
Authors: Nagao A , Miura K , Kitao S , Horio M 
Published: July 2016

Abstract
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.
Agronomic Performance of Flue-Cured Tobacco F1 Hybrids Obtained with Different Sources of Male Sterile Cytoplasm
Authors: Berbec A , Laskowska D 
Published: July 2016

Abstract
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 wereN. suaveolens,N. amplexicaulis,N. bigeloviiand aN. tabacumcms mutant. Under the slight to moderate pressure from black root rot present at the trial sites the hybrids showed a moderate tolerance of the disease characteristic of VG as opposed to medium strong susceptibility of Wislica. Apart from the effect of black root rot tolerance the vegetative vigor of the hybrids (plant height, leaf size, earliness) was affected by cytoplasm source. The F1hybrid withN. suaveolens cytoplasm flowered approximately three days later than the remaining hybrids. Of the cms hybrids tested cmsN. bigelovii produced the tallest plants with largest mid-position leaves. Yields of cured leaves were largely influenced by black root rot and were generally higher in VG and in the hybrids than in Wislica. Leaf yields and curability were generally little affected by cms source under low pressure from black root rot. At the site with a relatively high level of black root rot infestation the yields of cmsN. suaveolens were slightly lower but the percentage of light grades slightly higher compared to those of other cms hybrids. CmsN. suaveolens was the best hybrid in terms of money returns at the low black root rot field but it was the poorest hybrid performer under high pressure from the disease. Contents of nitrogen, sugars, nicotine and ash was little affected by source of cms. There was an increased incidence of potato virus Y (PVY) and white spots in cmsN. suaveolens and, to a lesser extent, in cmsN. bigelovii as compared to the remaining disease-free entries.
Measurement of Gas Diffusion Capacity of Cigarette Papers
Authors: Norman AB , Caudle JC , Henderson CW 
Published: July 2016

Abstract
Apparatus suitable for measuring gas diffusion capacity of cigarette paper was assembled and evaluated. The apparatus provides semi-automated means for measuring the concentration of carbon dioxide diffusing through a small area of the paper, and computation of a paper thickness-dependent diffusion capacity of the sample. Measurements are rapid and can be made in about 30 s. Diffusion capacity measurements were repeatable and reproducible to within about 1%. Variability of the diffusion capacity values was much lower than that observed for permeability measurements. For these reasons, the apparatus is useful for quality assessment and research applications. Diffusion capacity was measured for cigarette papers of inherent permeability ranging from 6 to 62 cm/min. As expected from prevailing theory, the diffusion capacity values generally increased with permeability. The diffusion capacity measured for electrostatically perforated papers was only slightly higher (about 6-11%) than the unperforated base paper despite large increases in permeability. This result indicates that diffusion capacity is governed by small pores in the paper. The apparatus is capable of measuring banded areas of papers designed for reduced ignition propensity. Diffusion capacity values for banded areas were lower than those of non-banded paper of similar permeability, suggesting that the band material preferentially occludes small pores in the paper.
Smoking Behavior: How Close to the Tipping Do Consumers Actually Smoke?
Authors: St. Charles FK , Kabbani AA , Ogden MW 
Published: July 2016

Abstract
When smoked by the Federal Trade Commission (FTC) method, the standard butt length for filtered cigarettes is specified as tipping plus 3 mm. One of the criticisms of this standard is that the tipping overlap hides some of the tobacco column and that consumers actually smoke cigarettes past the tipping.
The objective of this study was to determine how consumers actually smoke their usual brand when smoking in their everyday environment. A portable device was designed to collect and preserve cigarettes from consumers after smoking. In use, the smoldering cigarette is dropped into the device and it is closed. Upon closing, the cigarette is extinguished, the mouth end of the filter is cut and separated for further analysis, and the date and time are recorded.
Fifty adult smokers per brand were recruited across 5 US cities (10 smokers/city). A wide range of brands was studied: menthol and non-menthol, 1 mg to 18 mg FTC ‘tar’ yield, 17 to 25 mm circumference, and both 85 and 100 mm lengths. A total of 10528 cigarettes from 803 subjects covering 17 brands was measured.
The subjects were provided with one pack of their usual brand, as well as a collection device, and were instructed on how to use the device. The devices were collected on subsequent days. The cigarettes were then removed and the distance from the tipping to the char line was measured. The overall median butt length was tipping plus 6.7 mm with an overall average of tipping plus 8.4 mm. There was no significant effect of FTC ‘tar’ yield on either mean (p = 0.72) or median (p = 0.92) butt length.
A Simulation Study of Self-Extinguishing Cigarettes
Authors: Eitzinger B 
Published: July 2016

Abstract
In some parts of the USA and in Canada smouldering cigarettes are required to extinguish if placed on a certain number of layers of filter paper. This is usually achieved by the use of bands on the cigarette paper, which reduce oxygen diffusion into the cigarette. From a smoker's perspective, however, it is desirable that a cigarette does not extinguish if left to smoulder, for example, in an ash tray. To facilitate the design of papers for such cigarettes the influence of various cigarette parameters on self-extinguishment is investigated by numerical simulation of a one-dimensional cigarette model, which describes the main thermodynamic behaviour of smouldering cigarettes. The tobacco density, the tobacco heat capacity, the width of the bands on the cigarette paper and the heat released during combustion are chosen as parameters whose influence on the required oxygen diffusion constant of the bands on the cigarette paper is investigated. As these parameters are subject to a certain variation, it is assumed that the parameters are independently normally distributed. Based on this assumption the probability that a cigarette with given mean parameter values will extinguish, is calculated numerically.
The results show that the admissible range of diffusion constants for the bands on the cigarette paper is in general quite small and it is reduced even further if statistical variations of the cigarette parameters are considered.
The results provide guidelines for the appropriate choice of the diffusion constant of the bands on the cigarette paper such that the cigarettes comply with legal requirements and do not extinguish during normal smoking.
Low-Temperature Oxidation of CO in Smoke: A Review
Authors: Dyakonov AJ , Robinson EA 
Published: July 2016

Abstract
The low-temperature catalytic oxidation of CO has been reviewed, targeting its possible application to cigarette smoke. The treatment of CO in smoke by using a filter-packed catalyst is extremely complicated by the presence of a variety of chemically active gaseous compounds, a particulate phase, the high velocity of pulsing smoke flow, and ambient temperature. The relevant mechanisms of catalysis and the catalyst preparation variables that could help to overcome these problems are considered. Possible contributors to the overall kinetics that must include variety of diffusion processes were briefly discussed. The chemisorption of O2, CO and CO2 on Pd, Pt and Au and on partially reducible supports, surface reactions and oscillations of the CO oxidation rate were analyzed. The effects of the surface structure and electronic properties of the catalyst support, preparation conditions and presence of a second transition metal on the projected CO oxidation activity of the catalysts in smoke are also discussed. The reviewed catalyst preparation approaches can solve the low-temperature catalyst activity problem. However, more work is required to stabilize this activity of an air-exposed catalyst to provide a necessary shelf life for a cigarette. The greatest challenge seems to be a particular phase - exclusive selectivity that would not contradict with the necessary fast diffusion of gases through the catalyst pores.
Study of Growing Flue-cured Tobacco in Croatia under Various Conditions of Irrigation and Nitrogen Nutrition
Authors: Cavlek M , Tursic I , Cosic T 
Published: July 2016

Abstract
Three field experiments were conducted at the experimental station of the Tobacco Institute Zagreb in Pitomaca during the years 1990 and 1992, 1993-1996 and 1999-2000 to determine the effects of irrigation at different soil moisture levels [40-100%, 60-100%, 80-100% of plant available water, (PAW)], of different starting times of irrigation (vegetative phase, early flowering stage, continuously), and of irrigation combined with nitrogen nutrition (0, 20, 40, 60 kg/ha N) on the yields and quality of flue-cured tobacco. The first two experiments involved block methods, the third involved the split-plot method.
In the first experiment, irrigation led to an increase in yield (3-38%), in price/kg (15-69%) and in reducing sugar content (18-89%) and a reduction of nicotine content (20-39%) in the flue-cured leaves. Additional irrigation at the early flowering stage and constant maintenance of soil moisture at a higher level resulted in somewhat lower yields but better visually estimated tobacco quality and, as expected, had a marked influence on the contents of nicotine and reducing sugars.
In the second experiment, irrigated tobacco gave higher yields in two of the four trial years, which were significant in 1995 (13-21%), higher reducing sugar levels in 1994 (20-34%) and a marked reduction of nicotine content in cured leaves in all years (11-56%). Under conditions identical with or similar to those used in this research, irrigation may be started at the early flowering stage.
In the third experiment, in both years irrigated tobacco showed significantly higher yields, price/kg and reducing sugar levels and significantly lower nicotine content. Averaging the two years indicated increases of 17%, 12% and 26% and a decrease of 29%, respectively. Higher amounts of nitrogen fertilizer promoted yield (up to 32%) and nicotine content (up to 76%), while decreasing reducing sugar levels (by up to 52%). Also, the price/kg of tobacco fertilized with more than 20 kg/ha of nitrogen dropped by as much as 26%.