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We’ve built this digital research platform to provide academics everywhere with fast, stable and secure digital access to our library of over 110,000 scholarly books and 800,000 journal articles. We’ve tested the platform in close cooperation with leading academic institutions. If you have any questions or you notice something doesn’t quite work as it should, please visit our Help/FAQ page and let us know.
SUMMARY Performance of the CReSSmicro™ v.2.0.0 portable smoking topography device was evaluated in a controlled laboratory environment using a calibrated smoking machine to generate known, reproducible smoking topographies. Device performance was evaluated using unlit and lit cigarettes over a range of puff volumes (25 to 100 mL) at 2 s puff duration using a sine wave profile. The device missed 93% and 100% of the 25 mL/2 s puffs for unlit and lit cigarettes, respectively. The device underreported puff durations for the entire volume range, i.e., from 40 mL (0.9 ± 0.17 s) to 100 mL (1.6 ± 0.11 s) for both unlit and lit cigarettes. Puff volumes were under reported for lower volumes from 40 mL (25.6 ± 5.5 mL) to 70 mL (68.8 ± 3.7 mL) for both unlit and lit cigarettes and slightly over reported for higher volumes from 85 mL (89.4 ± 7.6 mL) to 100 mL (103.4 ± 9.8 mL) for lit cigarettes. Experimental results indicated that a 12.5–20mL/s (750–1,200 mL/min) flow threshold for puff recognition was responsible for the observed results. This study reinforces the importance of fully understanding device performance prior to performing clinical studies of human smoking topography. [Beitr. Tabakforsch. Int. 26 (2014) 19–25]
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Abstract A method was developed for the isolation of dibenzofuran (DBF) and its four methyl derivatives (MDBF) from cigarette smoke. Since an excess of alkanes was found to inhibit the column chromatographic separation of dibenzofurans, distribution systems had to be developed which, in the initial step of the analysis, would lead to an enrichment of DBF and MDBF with loss of the bulk of the tobacco smoke alkanes. The three distributions which lead to a preliminary concentration of these heterocyclics were the solvent pairs methanol/water (4:1) and n-hexane; n-hexane and dimethylformamide; and water/dimethylformamide (4:1) and n-hexane. The resulting tobacco ''tar" extract was chromatographed on deactivated alumina and subsequently on Sephadex LH-20. The final concentrate of DBF was separated into individual components by gas chromatography. With the aid of this method we separated from cigarette smoke dibenzofuran and 1-, 2-, 3- and 4-methyldibenzofurans. These five dibenzofurans were identified by the retention times in two gas chromatographic systems, ultra-violet absorption spectra, and mass spectral analysis. The final DBF concentrate from cigarette smoke also contains, as major components, acenaphthylene and fluorene. For the quantitative analysis we employed dibenzofuran-1,2,3,4,4a,9b-14C6 as internal standard. This labelled compound was synthesized by the Trippett method on a microscale from phenol and 2-bromocyclohexanone. The mainstream smoke of an 85 mm U.S. nonfilter cigarette contained 106 ng of dibenzofuran, 40 ng of 1-methyldibenzofuran, 100 ng of 2- and 3-methyldibenzofurans, and 52 ng of 4-methyldibenzofuran. The identification of DBF and its four methyl derivatives in cigarette smoke represents their first isolation from a respiratory environmet
We’ve built this digital research platform to provide academics everywhere with fast, stable and secure digital access to our library of over 110,000 scholarly books and 800,000 journal articles. We’ve tested the platform in close cooperation with leading academic institutions. If you have any questions or you notice something doesn’t quite work as it should, please visit our Help/FAQ page and let us know.
We’ve built this digital research platform to provide academics everywhere with fast, stable and secure digital access to our library of over 110,000 scholarly books and 800,000 journal articles. We’ve tested the platform in close cooperation with leading academic institutions. If you have any questions or you notice something doesn’t quite work as it should, please visit our Help/FAQ page and let us know.
Abstract A pipe-smoking machine was constructed which simulates pipe-smoking. A photo-electric cell and a perforated endless belt were used for the time-regulation. The reproducibility of the puff and interval duration was fair: that of the crude and dry condensate of two types of tobacco smoked in this machine requires more investigation
We’ve built this digital research platform to provide academics everywhere with fast, stable and secure digital access to our library of over 110,000 scholarly books and 800,000 journal articles. We’ve tested the platform in close cooperation with leading academic institutions. If you have any questions or you notice something doesn’t quite work as it should, please visit our Help/FAQ page and let us know.
We’ve built this digital research platform to provide academics everywhere with fast, stable and secure digital access to our library of over 110,000 scholarly books and 800,000 journal articles. We’ve tested the platform in close cooperation with leading academic institutions. If you have any questions or you notice something doesn’t quite work as it should, please visit our Help/FAQ page and let us know.
We’ve built this digital research platform to provide academics everywhere with fast, stable and secure digital access to our library of over 110,000 scholarly books and 800,000 journal articles. We’ve tested the platform in close cooperation with leading academic institutions. If you have any questions or you notice something doesn’t quite work as it should, please visit our Help/FAQ page and let us know.
Abstract A two-stage GLC system has been developed to produce a separation of cigarette smoke "semi-volatiles" into several hundred peaks per analysis. Quantitative measurements of the separated peak areas, with correction for baseline drift and an internal standard value, are made by an off-line computer, using a digital output obtained from the GLC system on punched tape. The main features of the computer program used are described, and typical output data are shown. Results of analyses dealing with cigarette smoke composition, and the selective effect of various filters, are presented. The use of neophytadiene as reference compound for the selectivity calculations is described
We’ve built this digital research platform to provide academics everywhere with fast, stable and secure digital access to our library of over 110,000 scholarly books and 800,000 journal articles. We’ve tested the platform in close cooperation with leading academic institutions. If you have any questions or you notice something doesn’t quite work as it should, please visit our Help/FAQ page and let us know.
We’ve built this digital research platform to provide academics everywhere with fast, stable and secure digital access to our library of over 110,000 scholarly books and 800,000 journal articles. We’ve tested the platform in close cooperation with leading academic institutions. If you have any questions or you notice something doesn’t quite work as it should, please visit our Help/FAQ page and let us know.
We’ve built this digital research platform to provide academics everywhere with fast, stable and secure digital access to our library of over 110,000 scholarly books and 800,000 journal articles. We’ve tested the platform in close cooperation with leading academic institutions. If you have any questions or you notice something doesn’t quite work as it should, please visit our Help/FAQ page and let us know.
Field experiments conducted in North Carolina during 1961-65 to compare the residual effectiveness of insecticidal sprays against Epitrix hirtipennis (Melsheimer) on flue-cured tobacco showed that, for the number of days indicated after application, the following treatments provided control similar to that obtained with 1 lb per acre of DDT: (1) for 10 days. 0.5 lb of carbofuran, Dasanit®( O, O -dicthyl O -[ P -(methylsulfinyl) phenyl] phosphorotluoate), dinwthoate. Gardona® (2-chloro-1-(2-4,5-trichlorophenyl) vinyl dimethyl phosphate), Imidan® ( O, O- dimethyl S-phthalimidornethyl phosphorodithioate), and Supracide® (S-((2-methoxy-5-oxo-∆2-1,3,4-thiadiazolin-4-yl) methyl) O, O -dimethyl phosphorodithioate), and 1 lb of aminocarb and MCA-600 (benzo[b]thien-4-yl methylcarbamate), (2) for 6 days, 0.25 lb of azinphosmethyl. 0.5 lb of dicrotophos and phosphamidon, and 1 lb of carbaryl, and (3) for 3 days, 0.25 lb of parathion and 1 lb of carbanolate. One-fourth lb of methyl parathion, 0.5 lb of diazinon, endosulfan, malathion, and naled, and 1 lb of TDE provided control inferior to that of 1 lb of DDT for 3 days and no significant control thereafter. Variable control was obtained with monocrotophos.
We’ve built this digital research platform to provide academics everywhere with fast, stable and secure digital access to our library of over 110,000 scholarly books and 800,000 journal articles. We’ve tested the platform in close cooperation with leading academic institutions. If you have any questions or you notice something doesn’t quite work as it should, please visit our Help/FAQ page and let us know.
Abstract Effects of sucker control chemicals on cell division and differentiation were studied by observing changes in root-tip cells continuously submerged in 5 × 10-3M solutions of MH-30 (maleic hydrazide), fatty ester T-43 (methyl caprate), fatty alcohol T-148 (mixture of 1-octanol and 1-decanol), Penar (dimethyldodecylamine acetate), and surfactants Tween-20 (polyoxyethylene sorbitan monolaurate) and Tween-80 (polyoxyethylene sorbitan monooleate). No adverse cytological effects were induced by surfactants. Meristematic cells treated with MH-30 appeared to be normal but there was no cell division. MH-30 also caused fragmentation or duplication of nuclei on differentiating cells. The effects of fatty materials (T-43 and T-148) include immediate swelling of the nucleus and then a general cessation of cell division. Penar caused enlargement of differentiating cells and nuclear fragmentation or duplication, a higher frequency of binucleate cells was found to be induced by Penar than T-148 or even MH-30. In general, sucker control compounds tested in this study induced a rather low incidence of endomitotic action which was limited to certain differentiating cells.
