Global burden of disease due to smokeless tobacco consumption in adults : analysis of data from 113 countries

BACKGROUND: Smokeless tobacco is consumed in most countries in the world. In view of its widespread use and increasing awareness of the associated risks, there is a need for a detailed assessment of its impact on health. We present the first global estimates of the burden of disease due to consumption of smokeless tobacco by adults. METHODS: The burden attributable to smokeless tobacco use in adults was estimated as a proportion of the disability-adjusted life-years (DALYs) lost and deaths reported in the 2010 Global Burden of Disease study. We used the comparative risk assessment method, which evaluates changes in population health that result from modifying a population's exposure to a risk factor. Population exposure was extrapolated from country-specific prevalence of smokeless tobacco consumption, and changes in population health were estimated using disease-specific risk estimates (relative risks/odds ratios) associated with it. Country-specific prevalence estimates were obtained through systematically searching for all relevant studies. Disease-specific risks were estimated by conducting systematic reviews and meta-analyses based on epidemiological studies. RESULTS: We found adult smokeless tobacco consumption figures for 115 countries and estimated burden of disease figures for 113 of these countries. Our estimates indicate that in 2010, smokeless tobacco use led to 1.7 million DALYs lost and 62,283 deaths due to cancers of mouth, pharynx and oesophagus and, based on data from the benchmark 52 country INTERHEART study, 4.7 million DALYs lost and 204,309 deaths from ischaemic heart disease. Over 85 % of this burden was in South-East Asia. CONCLUSIONS: Smokeless tobacco results in considerable, potentially preventable, global morbidity and mortality from cancer; estimates in relation to ischaemic heart disease need to be interpreted with more caution, but nonetheless suggest that the likely burden of disease is also substantial. The World Health Organization needs to consider incorporating regulation of smokeless tobacco into its Framework Convention for Tobacco Control

Cold rolled texture and microstructure in types 304 and 316L austenitic stainless steels

Two grades of austenitic stainless steel (ASS), types 304 (UNS S 30400) and 316L (UNS S 31603), were cold rolled to different reductions by unidirectional and by cross-rolling. The steels had reasonable difference in stacking fault energy (estimated respectively as 15 and 61 mJ/m(2) in types 304 and 316L) and also in starting (or pre-deformation) crystallographic texture-being relatively weak and reasonably strong in types 304 and 316L respectively. The cold rolling increased texturing in type 304, but not in type 316L ASS. The more significant effect of cold rolled texture development was in the relative increase of Brass ({011}) against Copper ({112}) and S ({231}) orientations. In type 304 the increase in Brass was significant, while in type 316L the increase in Copper and S was stronger. This effect could be captured by Taylor type deformation texture simulations considering stronger twinning contributions in type 304-for example the respective 'best-fits' (in terms of matching the changes in the volume fractions of Brass against Copper and S) were obtained by full constraint Taylor model with 1 : 100 and 1 : 10 slip: twin activities in types 304 and 316L ASS respectively. Microstructural developments during cold rolling were generalized as strain induced martensite formation and developments of dislocation substructure. The former, as estimated by vibrating sample magnetometer (VSM), increased with cold reduction, being significantly more in type 304 and was also noticeably stronger in both grades under cross-rolling. The most significant aspect of substructural developments was the formation of strain localizations. These were observed as dense dislocation walls (DDWs), micro-bands (MBs) and twin lamellar structures (TLS). The TLS contribution gained significance at higher reductions and during cross-rolling, especially in type 304. Large misorientation development and the accompanying grain splittings were always associated with such strain localizations. Efforts to relate Taylor factor (M) and textural softening (dM/depsilon) values (of ideal texture components) with relative misorientation developments was, however, unsuccessful. No consistent trend could be established for any unique combination(s) of slip-twin in the respective alloys

Precipitation stages in a 316L austenitic stainless steel

Detailed studies of precipitation in type 316L (UNS S31603) austenitic stainless steel were carried out by using a combination of differential scanning calorimetry, electrical resistivity measurement and transmission electron microscopy. Four distinct stages of precipitation were identified-coherent precipitation, its coarsening and initiation of grain boundary precipitation, a phase and finally M23C6 precipitation. (C) 2003 Acta Materialia Inc. .

Effects of overall grain boundary nature on localized corrosion in austenitic stainless steels

Thermo-mechanical processing of type 304 and type 316L stainless steels done by (a) cold rolling to a reduction in thickness of 20 to 80 percent and (b) solution annealing to obtain a medium size of grains led to a considerable improvement in resistance to both sensitization and intergranular corrosion. The nature of the resultant grain boundaries was examined in a scanning electron microscope using orientation imaging microscopy in electron back scattered diffraction mode. Fraction of random and special grain boundaries were established for each set of thermo-mechanical processing. After appropriate sensitization treatments, the degrees of sensitization of these stainless steels were evaluated by double loop electrochemical potentiokinetic reactivation tests. Standard ASTM tests were used to evaluate susceptibility to intergranular corrosion (IGC) and intergranular stress corrosion cracking (IGSCC). These studies showed that a particular combination of thermomechanical processing led to formation of over 75 percent random grain boundaries in the steels and this imparted resistance to sensitization and to IGC and IGSCC. This opens a new concept in grain boundary (GB) engineering of a high fraction of random GB increasing the resistance to localized corrosion like IGC and IGSCC. Textural studies were carried out with the help of X-ray and MTM-FHM software. It showed significant change of texture in type 304 stainless steel, while no change in the texture of type 316L stainless steel after cold rolling and annealing

Resistance to sensitization and intergranular corrosion through extreme randomization of grain boundaries

Two grades of austenitic stainless steel, type 304 and 316L, were cold rolled to different reductions by unidirectional and by cross rolling. Subsequent solutionizing of the cold rolled samples produced noticeable textural differences in type 304, but insignificant differences in type 316L. Both the solutionized materials had however the same trend in grain boundary character distribution (GBCD): an increasing fraction of random boundaries with an increasing presolutionizing reduction percentage. The degree of sensitization (DOS) was measured by the double loop electrochemical potentiokinetic reactivation (DL-EPR) test in both the alloys. The susceptibility to intergranular corrosion was assessed by the standard weight loss technique (practice B, A262 ASTM) in type 304 alloy. These increased with increase in random boundary concentration, but then dropped significantly beyond a 'critical' concentration-a pattern observed in both the grades. Such a pattern may be explained from a balance between nucleation rate of Cr-carbides and grain boundary Cr-flux, though postulating an exact model is premature at this stage. The present study, however, demonstrates a clear possibility of remarkable improvement in DOS and IGC through extreme grain boundary randomization. (C) 2002 Acta Materialia Inc. Published by Elsevier Science Ltd. All rights reserved.status: publishe

TiN coatings modified by an interlayer of electroplated chromium on mild steel

TiN films on mild steel were deposited by reactive d.c. magnetron sputtering; electroplated chromium was incorporated as an interlayer. Surface hardness, measured by the Knoop indentation method under a load of 25 gf. phase analysis by the X-ray diffraction method and corrosion behaviour by the potentiodynamic measurement technique of these coatings have been evaluated. Surface hardness values were found to increase from about 1000-1100 for TiN coatings on mild steel to about 1800-1900 (HK25) for TiN coatings with chromium as interlayer. Potentiodynamic corrosion tests, performed in 1N H2SO4 solutions, have shown that with chromium interlayer the corrosion resistance increases significantly as compared to TiN only sputtered coatings on mild steel samples. No spalling of TiN coatings was observed during full sweep voltage of -1000 mV to +1000 mV when they were tested with a chromium interlayer

Controlling grain boundary energy to make austenitic stainless steels resistant to intergranular stress corrosion cracking

Intergranular corrosion and intergranular stress corrosion cracking are the two localized corrosion mechanisms that are of concern to the typical applications of austenitic stainless steels in industries. Until recently, the common understanding was that a higher frequency of random boundaries increases the susceptibility, caused by a sensitization heat treatment or by operating temperatures, of austenitic stainless steels to both intergranular corrosion and intergranular stress corrosion cracking. A recent study([1]) demonstrated that extreme randomization of grain boundaries leads to a considerable improvement of resistance to both sensitization and intergranular corrosion. This work is a continuation of Ref. I and relates the effects of grain boundary randomization to intergranular stress corrosion cracking: the results show a trend consistent with earlier observations on intergranular corrosion. It is shown that there is improvement in resistance to intergranular stress corrosion cracking with extreme randomization of grain boundaries

Grain boundary nature and localized corrosion in 304 austenitic stainless steel

The present study had one broad objective - to systematically characterize effects of overall grain boundary nature on localized corrosion, intergranular corrosion (IGC) and stress corrosion cracking (IGSCC), of type 304 (UNS S 30400) austenitic stainless steel. Various combinations of cold rolling and solution annealing, were applied to alter relative the relative concentrations of 'special' or low CSL boundaries and to relate them with the local corrosion resistance, IGC and IGSCC, after respective sensitization treatments. It has been shown that both extreme high and low concentration of random (or high energy) boundaries can provide an effective means of control for localized corrosion, degree of sensitization (DOS), IGC and IGSCC, - the improvement in localized corrosion resistance at extreme grain boundary randomization being more effective