bluuebunny/crossref_metadata_2025_split huggingface dataset:
Guest Editorial
Authors: Klus H 
Published: July 2016

Abstract
In June 2001, the European Commission passed a new Directive for tobacco products, which, in addition to other regulations, obliges the manufacturers and importers of tobacco products in the EU to disclose the ingredients used in their products and also to submit data on the toxicological properties of these ingredients in burnt and unburnt form. The idea of monitoring and regulating additives used for tobacco products is rather old. Almost 200 years ago, C.F. Hareless in Nuremberg [cited in P.J. Schneider: Über die Gifte; Tübingen, 1821] established 12 rules for the correct use of ingredients in manufacturing tobacco products and vinegar. These rules cover almost all aspects for a consumer-friendly, responsible and safe use of additives for tobacco products and could, therefore, have served as an example for the present EU Tobacco Directive. For instance, Hareless states in Rule 4 that the manufacturer submits to the health department the prescriptions of all added ingredients in snuff and smoking tobacco. It was also planned that the responsible authority can perform unannounced “empirical” and “chemical” tests of the finished products (Rules 7 and 8). Although these rules call for strong regulation of ingredients, they do not challenge the use of additives in snuff and smoking tobacco because ingredients may contribute to the quality, acceptability and also the safety of the product. The Directive rightly asks for toxicological data of ingredients in burnt form, in order to be sure that the use of additives does not increase the biological effects of tobacco products. The review of Paschke, Scherer and Heller in this issue of BeiträgezurTabakforschung International/Contributions to Tobacco Research has compiled data from published papers on the toxicological effects of ingredients in burnt form. The authors did not intend to evaluate the presented methods and data, therefore, this review is more a reference work rather than a scientific article. It is obvious from the material presented that there is a lack of Standard Methods for testing the toxicological properties of tobacco ingredients in burnt form. The huge number of different approaches presented in this review points to the difficulties in defining suitable methods for this purpose. Despite these limitations, it is justified to state that the data so far available give no evidence that ingredients in use today increase the toxicity of tobacco smoke.
Mainstream Smoke Gas Phase Filtration Performance of Adsorption Materials Evaluated With A Puff-by-Puff Multiplex GC-MS Method
Authors: Xue L , Thomas CE , Koller KB 
Published: July 2016

Abstract
The mainstream smoke filtration performance of activated carbon, silica gel and polymeric aromatic resins for gas-phase components was evaluated using a puff-by-puff multiplex gas chromatography-mass spectrometry (GC-MS) analysis method (1). The sample 1R4F Kentucky reference cigarettes were modified by placing the adsorbents in a plug/space/plug filter configuration. Due to differences in surface area and structural characteristics, the adsorbent materials studied showed different levels of filtration activities for the twenty-six constituents monitored. Activated carbon had significant adsorption activity for all the gas-phase smoke constituents observed except ethane and carbon dioxide, while silica gel had significant activities for polar components such as aldehydes, acrolein, ketones, and diacetyl. XAD-16 polyaromatic resins showed varied levels of activity for aromatic compounds, cyclic dienes and ketones.
A Puff-by-Puff Delivery Model for Cigarettes
Authors: Chen P , Dwyer RW 
Published: July 2016

Abstract
Materials generated by combustion and pyrolysis in a lit cigarette move through the tobacco rod and filter sections in two phases, the particulate phase and the gas phase. Some particles are removed while moving through the rod and filter sections. The gas-phase materials include the vapor of many volatile compounds. While moving through the rod and filter sections, part of the vapor are removed by adsorption and condensation.
In this study, a puff-by-puff delivery model for cigarettes is developed to calculate “tar”, water, and nicotine in smoke on a puff-by-puff basis. A number of parameters can be obtained by the best fit to the experimental results of some cigarettes with different filter lengths. The parameters include the materials generated at the coal for each puff, the particle and vapor removal constants for tobacco rods and filters. The parameters may be useful in understanding some characteristics of cigarette smoke.
Transfer of Maleic Hydrazide into Mainstream Cigarette Smoke
Authors: Wood W , Dooly GL , Moldoveanu SC 
Published: July 2016

Abstract
This report presents the results of a study regarding the transfer of maleic hydrazide (MH) into mainstream cigarette smoke. Cigarettes with different levels of MH were used in this study. This included cigarettes with MH preexistent in the tobacco due to the agronomical practice, and with spiked MH. Because the MH can be present in tobacco as bound and free forms, both levels of MH were measured in the tobacco section. The cigarette designs covered a range of possibilities, including Plain, Filter King Size (KS), Lights 100’s, Ultra Lights, etc. The results showed that the amount of MH in smoke, on the one hand, is a function of the total particulate matter (TPM) of the cigarette, and higher TPM levels lead to more MH in smoke. On the other hand, the transferred level of MH depends on the total amount of MH (both bound and free) in the tobacco. The relative % transfer is higher for lower MH levels than for higher MH levels in tobacco. When normalized by TPM, the transfer as an average is about 0.24% per mg of TPM from the amount of MH in 1 g of tobacco, and as high as 0.46% per mg of TPM from the amount of MH in 1 g tobacco for a nonfilter low MH level cigarette. The resulting MH transfer for a nonfilter cigarette with low tobacco MH is therefore about 8.3% from the total MH in the cigarette. For filter full flavor (FF) cigarettes with high tobacco levels of MH, the transfer is about 5.8%. This relative transfer rate appears to be lower from higher MH levels in tobacco.
Thermal Emissivity and Cigarette Coal Temperature During Smolder
Authors: Lyman CS , Perfetti TA , Riggs DM , Morgan WT 
Published: July 2016

Abstract
Coal temperatures affect the burn properties of cigarettes. Thermal imaging was used to determine the average maximum surface coal temperatures during smolder of cigarettes of different tobacco types. The thermal imaging camera was calibrated against a reference blackbody. An emissivity correction was necessary since the set point temperatures of the reference blackbody did not correspond to the measured temperatures of the reference blackbody. A 0.87 camera emissivity was applied to provide accurate coal temperatures at a corrected emissivity of approximately 1. The average maximum surface coal temperatures during smolder of unfiltered single-tobacco-type cigarettes and a commercial blend cigarette were determined (with the camera lens focused parallel to the cigarette), and no discernible differences among them were found. The calculated average maximum surface coal temperature during smolder for all cigarettes was 584 AA± 15 °C. During smolder, thermocouples were used to measure the temperature of the gas phase (along the central axis of coal), and the thermal imaging camera was used to measure the temperature of the solid phase of the coal's surface. Using thermocouples, the peak coal temperatures in the center of the coal during smolder for three filtered single-tobacco-type cigarettes were 736-744 °C. Peak coal temperatures, measured by thermal imaging, on the surface of the coal (with the camera lens focused coaxially with the coal and the ash removed) for the same three single-tobacco-type cigarettes had a range of 721-748 °C. There was good correspondence between the two techniques. These results confirm that during smolder the gas-phase temperature inside the coal (as measured with the thermocouple) and the solid-phase temperatures beneath the ash (as measured with the camera) are in near thermal equilibrium. With proper calibration, a thermal imaging system is a good alternative to thermocouples for measuring cigarette coal temperatures.
Evolution of Tobacco-Specific Nitrosamines and Microbial Populations During Flue-Curing of Tobacco Under Direct and Indirect Heating
Authors: Morin A , Porter A , Joly J , Ratavicius A 
Published: July 2016

Abstract
Canadian tobacco was flue-cured using two different heating systems: direct-fired in which the exhaust gases were in contact with the tobacco and indirect in which only hot air, via a heat exchanger, contacted the tobacco. The concentrations of tobacco-specific nitrosamines (TSNAs) in tobacco cured by indirect heating did not increase during curing and were in the range 0.25-0.35 ppm. There were no changes in TSNA concentrations (range 0.13-0.3 ppm) in tobacco cured by direct firing during the first six days (0-144 h) of curing. However between 168 and 264 h, significant increases in TSNAs occurred (up to 1.91 ppm). TSNA concentrations in leaves at the bottom of the plant were significantly higher than in those found at higher plant position. There were no significant differences in TSNA concentrations in tobacco cured on different farms. The TSNA concentrations in tobacco cured by indirect heat were 87% ± 5% lower than in tobacco cured by direct heat. Subsequent processing of tobacco did not change the relative concentrations of TSNAs.
Chemistry of Cigarette Burning Processes
Authors: Chen P 
Published: July 2016

Abstract
Cigarette-burning and the smoke-formation processes and smoke composition are important topics for understanding cigarette performance. This paper proposes the molecular formulas representing the active components of bright, burley, and Oriental tobaccos and a basic chemistry model of the cigarette burning processes. Previous knowledge of the cigarette burning processes and smoke formation helped to establish parameters in deriving the basic chemistry equations. The proposed chemistry provides a brief view of the mechanisms of the cigarette burning during puffing and interpuff smoldering, and can be used to interpret and predict the smoke composition for cigarettes made from bright, burley, and Oriental tobaccos. Based on the proposed chemistry, the effect of ventilation on smoke component deliveries is discussed and the reaction heat of the puffing process is estimated.
Glycerol Transfer in Cigarette Mainstream Smoke
Authors: Liu C 
Published: July 2016

Abstract
Experiments have been conducted to examine the effect of different levels of blend glycerol (0 to 11.4 wt% on cigarette mainstream smoke (MSS) yields. The glycerol transfer is generally found to be proportional to the blend glycerol level with the maximum glycerol contribution to the nicotine-free-dry-particulate-matter (NFDPM or ‘tar’) per cigarette at 36% for a 11.4% blend glycerol. For cigarettes with different designs the glycerol in NFDPM may also depend on the glycerol loading per unit rod length. The tobacco rod filtration did not change significantly within the glycerol range investigated and hence plays a relatively minor role. Significant glycerol condensation ahead of the burning coal after a puff was measured. This condensation may have implications on glycerol levels in the sidestream smoke during inter-puff smouldering.
An Approach to Modeling a Burning Cigarette
Authors: Muramatsu M 
Published: July 2016

Abstract
The temperature and smoke components distributions inside a burning cigarette have been briefly reviewed. Then, focusing on our mathematical model to explain the natural smoldering mechanism of a cigarette and new mathematical models recently published by other authors, an approach to modeling a burning cigarette has been outlined.
It has been more than forty years since modeling the burning process of a cigarette was first attempted. Although the modeling work, which has been adopted as a means to research the burning mechanism of a cigarette, has seen a certain degree of progress in the last forty years, almost all mathematical models published are restricted to a burning cigarette under a free convection or a steady draw condition. No realistic model has been published yet to explain the processes occurring inside a burning cigarette under an intermittent puffing cycle.
A Profile of the Heat Generation Inside a Cigarette During Puffing
Authors: Nagao A , Yamada Y , Miura K , Horio M 
Published: July 2016

Abstract
The transient temperature distribution inside a burning cigarette during a 2-second constant-draw single puff was measured to determine the heat generation rate at various positions. The calculation of the heat generation was applied only to a vertically positioned cigarette. The solid-phase temperature was measured by an infrared thermometer with an optical fiber probe, and the gas-phase temperature was measured by a thermocouple. Heat generation rates at various positions inside the burning cigarette were obtained from the temperature distribution profile based on the heat balance equations. Heat generation was found to be concentrated within a region 2 to 3 mm behind the paper char line. The maximum heat generation rate was observed during the initial period of puffing and the heat generation rate decreased significantly in the interval during the middle unsteady period. Steady heat generation was observed in the latter period. The puffing volume as well as the properties of cigarette paper affected the heat generation rate during the unsteady period. The amount of the heat generated during the unsteady period was more than half of the total regardless of the cigarette paper basis weight and the puffing volume.
Factors Influencing the Formation of Tobacco-Specific Nitrosamines in French Air-Cured Tobaccos in Trials and at the Farm Level
Authors: deRoton C , Wiernik A , Wahlberg I , Vidal B 
Published: July 2016

Abstract
Several trials the results of which are compiled in this paper, were carried out at the Tobacco Institute of Bergerac (ITB) and in the area nearby from 1996 to 2003. The objective was to study the formation of tobacco-specific nitrosamines (TSNA) in dark air-cured and burley tobaccos during curing and post-curing treatment under the conditions of cultivation, curing and storage commonly applied by the growers in the south-western part of France. For experimental purposes special treatments were performed in certain trials.
The results showed that the main genetic trait involved in the formation of TSNA is the propensity of a variety to convert nicotine to nornicotine (NN). In addition, the ability of a variety to lose water rapidly limits the formation of nitrite and hence also the formation of TSNA. Furthermore, agricultural practices that led to an increase of alkaloid concentrations in the tobacco leaves also led to an increase of TSNA concentration. Priming, a mode of harvest which speeds up the cure, as compared to stalk-cutting, as well as low temperatures during curing, limit the formation of TSNA, but do not yield tobaccos of the best quality. Ventilation in the barn plays a major role, and the leaves cured in well ventilated curing structures, such as plastic sheds, generally contained smaller amounts of TSNA than leaves cured in a conventional curing barn. The results also indicated that the TSNA concentrations may increase after the end of cure, if the cured tobaccos were kept hanging in the barn under humid conditions. The concentration of TSNA may also continue to increase, whereas nitrite concentrations tend to decrease, when the leaves are kept in bales.
It can be concluded that the French climatic conditions with moderate temperatures and low relative humidity at the time of curing, are favourable for the production of air-cured tobaccos with a good quality and low TSNA concentrations (1.5-3.5 µg/g), provided that the variety has low NN content, the nitrogen fertilization is moderate, the curing is performed in a well ventilated environment, the tobacco is taken down and stripped as soon as it is cured, and the bales are stored as briefly as possible before the leaves are threshed and stabilized.
Formation of Tobacco-Specific Nitrosamines (TSNA) During Air-Curing: Conditions and Control
Authors: Staaf M , Back S , Wiernik A , Wahlberg I , Long RC , Young JH 
Published: July 2016

Abstract
The present review deals with studies performed during several consecutive years on the effect of air-curing on tobacco-specific nitrosamine (TSNA) formation and quality of tobacco. Temperature, relative humidity, water content and water activity data were collected during curing of dark tobacco in traditional air-curing barns and bulk-curing barns of different sizes, and chemical analysis of the cured tobacco were performed.
On an Optimal Choice of Pre-Perforated Tipping Paper and Porous Plug Wrap Paper
Authors: Eitzinger B 
Published: July 2016

Abstract
To minimize the effect of permeability variations of tipping and plug wrap paper on the degree of filter ventilation and consequently on the smoke yields, a mathematical model for the flow through a layered structure of perforated tipping paper and porous plug wrap paper was derived. The output of the model was compared to experimental data and a very good agreement was found.
A statistical investigation revealed that measured permeability values of tipping and plug wrap papers are normally distributed. Furthermore, it was shown that the statistical distribution of the total permeability of the layered structure cannot be distinguished from a normal distribution at reasonable levels of statistical significance.
Based on these investigations and on the mathematical model, expressions for the expected value and the coefficient of variation of the total permeability were derived. It was shown that in spite of the non-linear model the difference between the exact expected total permeability and a simple estimate calculated from the expected permeabilities of tipping and plug wrap is sufficiently small, such that for all practical purposes this estimate can be used.
The coefficient of variation of the total permeability was then minimized. The solution of this optimisation problem delivered practically applicable design rules for the permeabilities of tipping and plug wrap papers. It was shown that the minimal coefficient of variation of the total permeability is lower than the coefficient of variation of the permeability of tipping and plug wrap paper. Typically an optimal design can be achieved by choosing the tipping paper permeability between 10% and 50% higher than the total permeability. A simple example demonstrated the usefulness of this approach.
Analysis of Minor Alkaloids in Tobacco: A Collaborative Study
Authors: Chen PX , Qian N , Burton HR , Moldoveanu SC 
Published: July 2016

Abstract
A collaborative study regarding the analysis of minor alkaloids in tobacco and tobacco products was initiated by the Analytical Methods Committee of the Tobacco Science Research Conference (TSRC). One purpose of the study was to assess the reliability of methods used for the analysis of minor alkaloids and nicotine in tobacco and tobacco products, as practiced in different laboratories. A second purpose was to select a preferred method or to develop a hybrid method based on the best elements from the procedures currently used for the analysis of minor alkaloids. A hybrid method was developed and its results compared with the values from existing methods. The hybrid method proves to be reliable, has good repeatability, and is easy to implement. This new method can be used as a reference procedure for minor alkaloids and nicotine analysis using either flame ionization (FID) or mass spectrometric (MS) detection. A comparison with the older techniques shows that the hybrid method considerably improved the repeatability, but only marginally increased the reproducibility for different laboratories. This may be, in part, because any new method requires some time to become fully standardized and reliable. Also, the contribution of other sources of variation such as different standards and different equipment may have limited the improvement in reproducibility.
Numerical Simulation of a Cigarette during Smoking
Authors: Eitzinger B , Pirker S 
Published: July 2016

Abstract
A mathematical model for a lit cigarette is derived, which predicts pressure, flow velocity, temperature and gas concentrations inside and outside the cigarette. It consists of a continuum-mechanical model for the flow and a discrete model for the chemical reactions occurring in the tobacco particles.
The cigarette model is simulated for a cigarette in a vertical position by methods known as computational fluid dynamics (CFD). Calculated temperature and gas concentration profiles are compared to measured data from the literature for smouldering, puffing and steady-draw. For thermo-physical properties, such as temperature fields and burn rates, a good correspondence with experimental data was found. The correspondence with measured gas concentration profiles was also acceptable, even though the reaction model is rather simple. The results show the importance of including the surroundings of the cigarette in the computational domain.
Secondly, a cigarette in a horizontal position is simulated both for free smouldering and for smouldering on a substrate, as occurs, for example, during the ignition strength test. The results show certain qualitative differences between the two smouldering regimes in the flow pattern outside the cigarette and in the transfer of heat to the surroundings and to the substrate.
The proposed model offers two main advantages. Firstly, it does not need the input of any data, that can only be measured if the cigarette has been lit, such as temperature fields or burn rates. Secondly, with this model all types of smoking regimes such as smouldering, puffing and steady-draw can be simulated without making any modifications to the mathematical model or its parameters. Only the boundary conditions need to be adapted.
Analysis of Protein Amino Acids in Tobacco Using Microwave Digestion of Plant Material
Authors: Moldoveanu SC 
Published: July 2016

Abstract
This paper describes a technique using microwave digestion and gas chromatography-mass spectrometry (GC-MS), which makes possible the analysis of protein amino acids in tobacco. The technique involves first the measurement of free amino acids, a hydrolysis using microwave digestion, and a measurement of total resulting amino acids. The content of protein amino acids is determined from the difference of total and free amino acids. The digestion is performed with aqueous 6 N HCl (with 1% phenol) for two hours in a microwave at 120°C in sealed vials. The GC-MS analysis is performed after the amino acids are derivatized with N-methyl-N-(t-butyldimethylsilyl)trifluoroacetamide (MTBSTFA). The technique provides reliable results with less than 10% relative standard deviation (RSD) for most amino acids. Only the determination of very low level amino acids is affected by larger errors. The method provides results for free amino acids that are in very good agreement with those obtained by high performance liquid chromatography (HPLC), and also results for protein levels in tobacco in agreement with data previously reported in the literature. Results are given for several single grade tobaccos and for tobacco blends from four Kentucky reference cigarettes.