scholarly journals The Complexity of Tobacco and Tobacco Smoke

2011 ◽  
Vol 24 (5) ◽  
pp. 215-232 ◽  
Author(s):  
TA Perfetti ◽  
A Rodgman
Keyword(s):  
Tobacco Smoke ◽  
Complex Mixture ◽  
Operational Definition ◽  
Biological Properties ◽  
Complex Mixtures ◽  
Chemical Components ◽  
Detailed Knowledge ◽  
Polycyclic Aromatic ◽  
Definition Of ◽  
Risk Potential

AbstractTobacco and tobacco smoke are both complex mixtures. We previously reported 8430 unique chemical components identified in these complex mixtures but two years later our updated number was 8889. Addition of unlisted isomers raised these numbers to 8622 and 9081, respectively. Our previous number of 4994 identified tobacco components is now 5229; our previous number of 5315 identified tobacco smoke components is now 5685. An operational definition of a complex mixture is as follows: A complex mixture is a characterizable substance containing many chemical components (perhaps thousands) in inexact proportions.Detailed knowledge of the amount and type of each component within the substance is uncertain even with today's analytical technology. Although it has been estimated that as many as 100000 components are present in these complex mixtures, their analyses indicate that the vast majority of the mass of each of these complex mixtures accounts for the 8430 compounds reported previously. Over 98.7% of the mass of tobacco has been accounted for in terms of identified components in tobacco. Greater than 99% of the mass of whole smoke has been accounted for based on identified chemical components. Certainly, many more tobacco and tobacco smoke components are present in these complex mixtures but the total mass of these components obviously is quite small.One of the significant challenges we face as a scientific community is addressing the problems of determining the risk potential of complex mixtures. Many issues are associated with toxicological testing of the complex mixture of tobacco smoke. Conducting valid experiments and interpreting the results of those experiments can be quite difficult. Not only is the test agent a complex mixture but also the tests are performed on species that have complicated life-processes. Interpretations of test results are often paradoxical. Significant progress has been made in the toxicological evaluations of complex mixtures in the last 80 years. The challenges we face in terms of testing the biological properties of tobacco smoke are substantial. The statement by DIPPLE et al. in their summary of the research on polycyclic aromatic hydrocarbons from the 1930s through 1980 is equally true today for the cigarette smoke situation:…many important questions remain unanswered…many questions persist despite the considerable progress that has been made.

scholarly journals The Chemical Components Identified in Tobacco and Tobacco Smoke Prior to 1954: A Chronology of Classical Chemistry

2009 ◽  
Vol 23 (5) ◽  
pp. 277-333 ◽  
Author(s):  
A Rodgman ◽  
TA Perfetti
Keyword(s):  
Tobacco Smoke ◽  
Biological Properties ◽  
Complex Mixtures ◽  
Commercial Product ◽  
Chemical Components ◽  
Research Results ◽  
Meaningful Information ◽  
Chemical Techniques ◽  
Early Information ◽  
The Many

AbstractBecause of the excellent fractionation and identification technologies developed during the early-1950s, the compositions of tobacco and tobacco smoke, both classified as highly complex mixtures, have been defined more completely than the composition of any other highly complex commercial product such as coffee. By year-end 1953, the many years of research by scientists using classical chemical techniques to define the composition of tobacco and its smoke provided meaningful information on the nature of over 300 tobacco components and fewer than 100 tobacco smoke components. Those involved in the pre-1954 research not only provided the cornerstone of our knowledge of the two compositions but also deserve the gratitude of their successors for the early information generated on tobacco and its smoke. This article is our tribute to those researchers who generated much meaningful knowledge on the composition of tobacco and tobacco smoke prior to 1954 despite the now known fractionation and analytical limitations of the so-called classical chemical techniques. It also notes the similarity of some of the early and more recent research results obtained on the chemical and biological properties of smoke condensate and several of its components from tobacco with those obtained by Roffo in the 1930s on a destructive distillate of tobacco.

scholarly journals The Composition of Cigarette Smoke. An Historical Perspective of Several Polycyclic Aromatic Hydrocarbons

2009 ◽  
Vol 23 (6) ◽  
pp. 384-410 ◽  
Author(s):  
A Rodgman ◽  
LC Cook
Keyword(s):  
Polycyclic Aromatic Hydrocarbons ◽  
Melting Point ◽  
Cigarette Smoke ◽  
Aromatic Hydrocarbons ◽  
Tobacco Smoke ◽  
Individual Component ◽  
Complex Mixtures ◽  
Polycyclic Aromatic ◽  
The Individual ◽  
Cigarette Mainstream Smoke

AbstractBecause of the significant advancements in fractionation, analytical, and characterization technologies since the early 1960s, hundreds of components of complex mixtures have been accurately characterized without the necessity of actually isolating the individual component. This has been particularly true in the case of the complex mixtures tobacco and tobacco smoke. Herein, an historical account of a mid-1950 situation concerning polycyclic aromatic hydrocarbons (PAHs) in cigarette smoke is presented. While the number of PAHs identified in tobacco smoke has escalated from the initial PAH, azulene, identified in 1947 to almost 100 PAHs identified by late 1963 to more than 500 PAHs identified by the late 1970s, the number of PAHs isolated individually and characterized by several of the so-called classical chemical means (melting point, mixture melting point, derivative preparation and properties) in the mid-1950s and since is relatively few, 14 in all. They were among 44 PAHs identified in cigarette mainstream smoke and included the following PAHs ranging from bicyclic to pentacyclic: Acenaphthylene, 1,2-dihydroacenaphthylene, anthracene, benz[a]anthracene, benzo[a]pyrene, chrysene, dibenz[a, h]anthracene, fluoranthene, 9H-fluorene, naphthalene, 1-methylnaphthalene, 2-methylnaphthalene, phenanthrene, and pyrene. One of them, benzo[a]pyrene, was similarly characterized in another study in 1959 by Hoffmann.

scholarly journals Comparisons of the Composition of Tobacco Smoke and the Smokes from Various Tobacco Substitutes

2007 ◽  
Vol 22 (4) ◽  
pp. 258-289 ◽  
Author(s):  
CR Green ◽  
JN Schumacher ◽  
RA Lloyd ◽  
A Rodgman
Keyword(s):  
Research And Development ◽  
Tobacco Smoke ◽  
Biological Properties ◽  
Consumer Acceptability ◽  
Mainstream Smoke ◽  
Reconstituted Tobacco Sheet ◽  
Considerable Research ◽  
Definition Of ◽  
Smoke Tobacco ◽  
Cigarette Design

AbstractBy the late 1970s, eight technologies in the design of a ‘less hazardous’ cigarette were classified as significant. The eight included: The tobacco blend, the filter tip, filter-tip additives, reconstituted tobacco sheet, paper additives, air dilution via paper porosity, expanded tobacco, and air dilution via filter-tip perforation. In addition to these eight cigarette-design technologies was another proposed technology which involved the incorporation of a substitute for some or all of the tobacco in the cigarette filler. Despite considerable research and development (R&D) effort on various tobacco substitutes that indicated the replacements in most instances fulfilled the definition of a ‘less hazardous’ cigarette with regard to the chemical and biological properties of their mainstream smoke, tobacco substitute-containing cigarettes failed to attain consumer acceptability. As a result, several marketed products containing tobacco substitutes had an extremely brief tenure in the marketplace. Outlined herein is a summary of some detailed research conducted on the composition of the mainstream smokes from cigarettes containing either all-substitute filler or fillers comprising various substitute and tobacco mixtures as well as an all-tobacco cigarette.

The composition of cigarette smoke: a retrospective, with emphasis on polycyclic components

2000 ◽  
Vol 19 (10) ◽  
pp. 573-595 ◽  
Author(s):  
A Rodgman ◽  
C J Smith ◽  
T A Perfetti
Keyword(s):  
Biological Activity ◽  
Cigarette Smoke ◽  
Tobacco Smoke ◽  
Complex Mixture ◽  
Mouse Skin ◽  
Chemical Indicators ◽  
Polycyclic Aromatic ◽  
Mechanistic Basis ◽  
Cigarette Mainstream Smoke ◽  
Aza Arenes

The difficulties encountered in extrapolating biological activity from cigarette smoke composition provide generally applicable lessons as they are representative of the problems encountered with other complex mixtures. Researchers attempting to assess risk are faced with attempting to interpret data from a number of areas including: tobacco science; smoke/aerosol chemistry specific to tobacco; sophisticated analytical chemistry applications and techniques for trapping, collecting, separating, and quantifying very specific compounds at nanogram to picogram levels; numerous biological testing methodologies; and animal models of tumors and carcinogenesis. Numerous hypotheses have been developed over the past five decades and tested with the technology of the day in attempts to interpret the biological activity of cigarette smoke in relation to the chemistry of this complex mixture. These hypotheses fall into several categories discussed in this review: mechanisms of pyrogenesis of polycyclic aromatic hydrocarbons (PAHs) in tobacco smoke; levels of PAHs in cigarette mainstream smoke (MS) and its tumorigenicity in mouse skin-painting experiments; control of PAH levels in MS; chemical indicators of cigarette smoke condensate (CSC) tumorigenicity; control of levels of MS components partitioned between the vapor phase and particulate phase of MS; tumorigenic threshold limits of CSC and many of its components; tumorigenic aza-arenes in tobacco smoke; MS components reported to be ciliastatic to smokers' respiratory tract cilia; anticarcinogenic tobacco-smoke components. Of 52 hypotheses reviewed in this paper, 15 have excellent data supporting the hypothesis based on today's technology. The remaining 37 hypotheses, although originally plausible, have since become insupportable in light of new and contradictory data generated over the years. Such data were generated sometimes by the original authors of the hypotheses and sometimes by other investigators. The hypotheses presented today are less likely to be supplanted because they are well conceived and have a strong mechanistic basis. The challenge for the future is the generation and interpretation of data relating the chemistry and biological activity associated with the dynamic and complex mixture of tobacco smoke.

Understanding functional illiteracy from a policy, adult education, and cognition point of view: Towards a joint referent framework

2019 ◽  
Vol 30 (2) ◽  
pp. 109-122
Author(s):  
Aleksandar Bulajić ◽  
Miomir Despotović ◽  
Thomas Lachmann
Keyword(s):  
Adult Education ◽  
Operational Definition ◽  
Literacy Skills ◽  
Point Of View ◽  
Industrialized Countries ◽  
Functional Illiteracy ◽  
Scale Levels ◽  
Components Of Reading ◽  
The One ◽  
Definition Of

Abstract. The article discusses the emergence of a functional literacy construct and the rediscovery of illiteracy in industrialized countries during the second half of the 20th century. It offers a short explanation of how the construct evolved over time. In addition, it explores how functional (il)literacy is conceived differently by research discourses of cognitive and neural studies, on the one hand, and by prescriptive and normative international policy documents and adult education, on the other hand. Furthermore, it analyses how literacy skills surveys such as the Level One Study (leo.) or the PIAAC may help to bridge the gap between cognitive and more practical and educational approaches to literacy, the goal being to place the functional illiteracy (FI) construct within its existing scale levels. It also sheds more light on the way in which FI can be perceived in terms of different cognitive processes and underlying components of reading. By building on the previous work of other authors and previous definitions, the article brings together different views of FI and offers a perspective for a needed operational definition of the concept, which would be an appropriate reference point for future educational, political, and scientific utilization.

“The Unconscious” in Current Psychology

2010 ◽  
Vol 15 (3) ◽  
pp. 193-201 ◽  
Author(s):  
Elisabeth Norman
Keyword(s):  
Cognitive Psychology ◽  
Verbal Report ◽  
Psychological Research ◽  
Operational Definition ◽  
The Unconscious ◽  
Apparent Lack ◽  
Unconscious Processing ◽  
Unconscious Processes ◽  
Intermediate States ◽  
Definition Of

A series of vignette examples taken from psychological research on motivation, emotion, decision making, and attitudes illustrates how the influence of unconscious processes is often measured in a range of different behaviors. However, the selected studies share an apparent lack of explicit operational definition of what is meant by consciousness, and there seems to be substantial disagreement about the properties of conscious versus unconscious processing: Consciousness is sometimes equated with attention, sometimes with verbal report ability, and sometimes operationalized in terms of behavioral dissociations between different performance measures. Moreover, the examples all seem to share a dichotomous view of conscious and unconscious processes as being qualitatively different. It is suggested that cognitive research on consciousness can help resolve the apparent disagreement about how to define and measure unconscious processing, as is illustrated by a selection of operational definitions and empirical findings from modern cognitive psychology. These empirical findings also point to the existence of intermediate states of conscious awareness, not easily classifiable as either purely conscious or purely unconscious. Recent hypotheses from cognitive psychology, supplemented with models from social, developmental, and clinical psychology, are then presented all of which are compatible with the view of consciousness as a graded rather than an all-or-none phenomenon. Such a view of consciousness would open up for explorations of intermediate states of awareness in addition to more purely conscious or purely unconscious states and thereby increase our understanding of the seemingly “unconscious” aspects of mental life.

An Analysis of the Demand for Reporting on Internal Control

2000 ◽  
Vol 14 (3) ◽  
pp. 325-341 ◽  
Author(s):  
Heather M. Hermanson
Keyword(s):  
Decision Making ◽  
Financial Reporting ◽  
Internal Control ◽  
Operational Definition ◽  
Financial Statement ◽  
Individual Investors ◽  
Internal Auditors ◽  
Additional Information ◽  
User Groups ◽  
Definition Of

The purpose of this study is to analyze the demand for reporting on internal control. Nine financial statement user groups were identified and surveyed to determine whether they agree that: (1) management reports on internal control (MRIC) are useful, (2) MRICs influence decisions, and (3) financial reporting is improved by adding MRICs. In addition, the paper examined whether responses varied based on: (1) the definition of internal control used (manipulated as broad, operational definition vs. narrow, financial-reporting definition) and (2) user group. The results indicate that financial statement users agree that internal controls are important. Respondents agreed that voluntary MRICs improved controls and provided additional information for decision making. Respondents also agreed that mandatory MRICs improved controls, but did not agree about their value for decision making. Using a broad definition of controls, respondents strongly agreed that MRICs improved controls and provided a better indicator of a company's long-term viability. Executive respondents were less likely to agree about the value of MRICs than individual investors and internal auditors.

Shape Dynamics and the Linking Theory

2018 ◽  
Author(s):  
Flavio Mercati
Keyword(s):  
Phase Space ◽  
Degrees Of Freedom ◽  
Line Element ◽  
Hamiltonian Formulation ◽  
Operational Definition ◽  
Extended Phase Space ◽  
Extended Phase ◽  
Problem Of Time ◽  
Definition Of ◽  
Matter Fields

This chapter explains in detail the current Hamiltonian formulation of SD, and the concept of Linking Theory of which (GR) and SD are two complementary gauge-fixings. The physical degrees of freedom of SD are identified, the simple way in which it solves the problem of time and the problem of observables in quantum gravity are explained, and the solution to the problem of constructing a spacetime slab from a solution of SD (and the related definition of physical rods and clocks) is described. Furthermore, the canonical way of coupling matter to SD is introduced, together with the operational definition of four-dimensional line element as an effective background for matter fields. The chapter concludes with two ‘structural’ results obtained in the attempt of finding a construction principle for SD: the concept of ‘symmetry doubling’, related to the BRST formulation of the theory, and the idea of ‘conformogeometrodynamics regained’, that is, to derive the theory as the unique one in the extended phase space of GR that realizes the symmetry doubling idea.

scholarly journals Biological Properties of Essential Oils from Thymus algeriensis Boiss

Plants ◽  
2021 ◽  
Vol 10 (4) ◽  
pp. 786
Author(s):  
Hamza Ouakouak ◽  
Adel Benarfa ◽  
Mohammed Messaoudi ◽  
Samir Begaa ◽  
Barbara Sawicka ◽  
...  
Keyword(s):  
Essential Oils ◽  
Micrococcus Luteus ◽  
Radical Scavenging Activity ◽  
Radical Scavenging ◽  
Cancer Cell Line ◽  
Antimicrobial Activities ◽  
Biological Properties ◽  
Chemical Components ◽  
Bornyl Acetate ◽  
Thymus Algeriensis

This study describes the chemical composition, antitumor, antioxidant, and antimicrobial activities of the plant Thymus algeriensis Boiss. Essential oils (EOs) were collected in different periods (before, during, and after flowering stage) from the El-Guetfa region, M’sila, Algeria. The EOs extraction was achieved using three distinguishing techniques: hydro (Clevenger trap), steam, and microwave distillations, targeting different aerial parts of the plant (stems, flowers, and leaves). The EOs chemical components were estimated using GC-FID and GC-MS apparatuses. The resulting yield of the extracted oil was moderate and ranged between 0.84 and 1.53% (wt/vol). In total, eighty-five components were identified, in which the oxygenated monoterpenes family formed the main portion, starting from 40.56 up to 70.66%. The obtained essential oil was dominated by five major components that varied from low to quite moderate percentages: camphor (17.45–32.56%), borneol (11.16–22.2%), camphene (7.53–12.86%), 1.8-cineole (5.16–11.21%), and bornyl acetate (3.86–7.92%). The biological results of this oil pointed out that the EOs extracted from the leaves part exposed a weak radical scavenging activity afterward using two well-known antioxidant assays DPPH (IC50 = 8.37 mg/mL) and ABTS (10.84 mg/mL). Meanwhile, this oil presented strong inhibition activity against colon cancer cell line HCT116 (LC50 = 39.8 µg/mL) and a moderate inhibitory against hepatocellular cancer cells HePG2 (LC50 > 100 µg/mL). In addition, this oil antimicrobial activity was quite important against Micrococcus luteus (M. luteus), Staphylococcus aureus CIP 7625, Escherichia coli ATCC 10536, Saccharomyces cerevisiae ATCC 4226, Candida albicans IPA200, Candida tropicalis (Ct), and Candida glabrata (Cg) after using Amoxicillin and Itraconazole as references.

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