Three-dimensional charge transport mapping by two-photon absorption edge transient-current technique in synthetic single-crystalline diamond

We demonstrate the application of two-photon absorption transient current technique to wide bandgap semiconductors. We utilize it to probe charge transport properties of single-crystal Chemical Vapor Deposition (scCVD) diamond. The charge carriers, inside the scCVD diamond sample, are excited by a femtosecond laser through simultaneous absorption of two photons. Due to the nature of two-photon absorption, the generation of charge carriers is confined in space (3-D) around the focal point of the laser. Such localized charge injection allows to probe the charge transport properties of the semiconductor bulk with a fine-grained 3-D resolution. Exploiting spatial confinement of the generated charge, the electrical field of the diamond bulk was mapped at different depths and compared to an X-ray diffraction topograph of the sample. Measurements utilizing this method provide a unique way of exploring spatial variations of charge transport properties in transparent wide-bandgap semiconductors.Comment: This article may be downloaded for personal use only. Any other use requires prior permission of the author and AIP Publishing. The following article appeared in Applied Physics Letters and may be found at https://doi.org/10.1063/1.509085

Processed meat and the risk of selected digestive tract and laryngeal neoplasms in Switzerland

Background: Processed meat has been related to the risk of digestive tract neoplasms but the evidence remains inconclusive. We examined data from a network of case-control studies conducted between 1992 and 2002 in the Swiss Canton of Vaud. Patients and methods: We studied 316 patients with incident, histologically confirmed oral and pharyngeal cancer, 138 patients with oesophageal cancer, 91 patients with laryngeal cancer and 323 patients with colorectal cancer. Controls were 1271 subjects admitted to the same hospital for a wide spectrum of acute non-neoplastic conditions, unrelated to long-term modification of diet. Results: There were strong direct trends in risk between consumption of processed meat and the various neoplasms considered: the multivariate odds ratios for the highest quartile of intake compared to the lowest were 4.7 for oral and pharyngeal cancer, 4.5 for oesophageal cancer, 3.4 for laryngeal cancer and 2.5 for colorectal cancer. The association was stronger in younger subjects, in moderate drinkers and in non-smokers. Conclusion: Processed meat represents a strong indicator of unfavourable diet for digestive tract and laryngeal cancer risk in this populatio

Lung cancer mortality in European women: recent trends and perspectives

Background: Lung cancer mortality in men has been declining since the late 1980s in most European countries. In women, although rates are still appreciably lower than those for men, steady upward trends have been observed in most countries. To quantify the current and future lung cancer epidemic in European women, trends in lung cancer mortality in women over the last four decades were analyzed, with specific focus on the young. Patients and methods: Age-standardized (world standard) lung cancer mortality rates per 100 000 women—at all ages, and truncated 35-64 and 20-44 years—were derived from the WHO for the European Union (EU) as a whole and for 33 separate European countries. Joinpoint regression analysis was used to identify points where a significant change in trends occurred. Results: In the EU overall, female lung cancer mortality rates rose by 23.8% between 1980-1981 and 1990-1991 (from 7.8 to 9.6/100 000), and by 16.1% thereafter, to reach the value of 11.2/100 000 in 2000-2001. Increases were smaller in the last decade in several countries. Only in England and Wales, Latvia, Lithuania, Russia and Ukraine did female lung cancer mortality show a decrease over the last decade. In several European countries, a decline in lung cancer mortality in young women (20-44 years) was observed over the last decade. Conclusions: Although female lung cancer mortality is still increasing in most European countries, the more favorable trends in young women over recent calendar years suggest that if effective interventions to control tobacco smoking in women are implemented, the lung cancer epidemic in European women will not reach the levels observed in the US

Continuing declines in cancer mortality in the European Union

Background: From 1988 to 1997 age-standardised total cancer mortality rates in the European Union (EU) fell by around 9% in both sexes. Available cancer mortality data in Europe up to 2002 allow a first check of the forecast of further declines in cancer mortality. Patients and methods: We considered trends in age-standardised mortality from major cancer sites in the EU during the period 1980-2002. Results: For men, total cancer mortality, after a peak of 191.1/100 000 in 1987 declined to 177.8 in 1997 (−7%), and to 166.5 in 2002. Corresponding figures for females were 107.9/100 000, 100.5 and 95.2, corresponding to falls of 7% from 1987 to 1997, and to 5% from 1997 to 2002. Over the last 5 years, lung cancer declined by 1.9% per year in men, to reach 44.4/100 000, but increased by 1.7% in women, to reach 11.4. In 2002, for the first year, lung cancer mortality in women was higher than that for intestinal cancer (11.1/100 000), and lung cancer became the second site of cancer deaths in women after breast (17.9/100 000). From 1997 to 2002, appreciable declines were observed in mortality from intestinal cancer in men (−1.6% per year, to reach 18.8/100 000), and in women (−2.5%), as well as for breast (−1.7% per year) and prostate cancer (−1.4%). Conclusions: Despite the persisting rises in female lung cancer, the recent trends in cancer mortality in the EU are encouraging and indicate that an 11% reduction in total cancer mortality from 2000 to 2015 is realistic and possibl

Declining mortality from kidney cancer in Europe

Mortality rates from kidney cancer increased throughout Europe up until the late 1980s or early 1990s. Trends in western European countries, the European Union (EU) and selected central and eastern European countries have been updated using official death certification data for kidney cancer abstracted from the World Health Organisation (WHO) database over the period 1980-1999. In EU men, death rates increased from 3.92 per 100 000 (age standardised, world standard) in 1980-81 to 4.63 in 1994-95, and levelled off at 4.15 thereafter. In women, corresponding values were 1.86 in 1980-81, 2.04 in 1994-95 and 1.80 in 1998-99. Thus, the fall in kidney cancer mortality over the last 5 years was over 10% for both sexes in the EU. The largest falls were in countries with highest mortality in the early 1990s, such as Germany, Denmark and the Netherlands. Kidney cancer rates levelled off, but remained very high, in the Czech Republic, Baltic countries, Hungary, Poland and other central European countries. Thus, in the late 1990s, a greater than three-fold difference in kidney cancer mortality was observed between the highest rates in the Czech Republic, the Baltic Republics and Hungary, and the lowest ones in Romania, Portugal and Greece. Tobacco smoking is the best recognised risk factor for kidney cancer, and the recent trends in men, mainly in western Europe, can be related to a reduced prevalence of smoking among men. Tobacco, however, cannot account for the recent trends registered in wome

Food groups and colorectal cancer risk

Most studies of diet and colorectal cancer have considered nutrients and micronutrients, but the role of foods or food groups remains open to debate. To elucidate the issue, we examined data from a case–control study conducted between 1992 and 1997 in the Swiss canton of Vaud. Cases were 223 patients (142 men, 81 women) with incident, histologically confirmed colon (n = 119) or rectal (n = 104) cancer (median age 63 years), linked with the Cancer Registry of the Swiss Canton of Vaud, and controls were 491 subjects (211 men, 280 women, median age 58 years) admitted to the same university hospital for a wide spectrum of acute non-neoplastic conditions unrelated to long-term modifications of diet. Odds ratios (OR) were obtained after allowance for age, sex, education, smoking, alcohol, body mass index, physical activity and total energy intake. Significant associations were observed for refined grain (OR = 1.32 for an increase of one serving per day), and red meat (OR = 1.54), pork and processed meat (OR = 1.27), alcohol (OR = 1.28), and significant protections for whole grain (OR = 0.85), raw (OR = 0.85) and cooked vegetables (OR = 0.69), citrus (OR = 0.86) and other fruits (OR = 0.85), and for coffee (OR = 0.73). Garlic was also protective (OR = 0.32 for the highest tertile of intake). These findings in a central European population support the hypothesis that a diet rich in refined grains and red meat increases the risk of colorectal cancer; they, therefore, support the recommendation to substitute whole grains for refined grain, to limit meat intake, and to increase fruit and vegetable consumption. © 1999 Cancer Research Campaig

Effects of fuel cetane number on the structure of diesel spray combustion: An accelerated Eulerian stochastic fields method

An Eulerian stochastic fields (ESF) method accelerated with the chemistry coordinate mapping (CCM) approach for modelling spray combustion is formulated, and applied to model diesel combustion in a constant volume vessel. In ESF-CCM, the thermodynamic states of the discretised stochastic fields are mapped into a low-dimensional phase space. Integration of the chemical stiff ODEs is performed in the phase space and the results are mapped back to the physical domain. After validating the ESF-CCM, the method is used to investigate the effects of fuel cetane number on the structure of diesel spray combustion. It is shown that, depending of the fuel cetane number, liftoff length is varied, which can lead to a change in combustion mode from classical diesel spray combustion to fuel-lean premixed burned combustion. Spray combustion with a shorter liftoff length exhibits the characteristics of the classical conceptual diesel combustion model proposed by Dec in 1997 (http://dx.doi.org/10.4271/970873), whereas in a case with a lower cetane number the liftoff length is much larger and the spray combustion probably occurs in a fuel-lean-premixed mode of combustion. Nevertheless, the transport budget at the liftoff location shows that stabilisation at all cetane numbers is governed primarily by the auto-ignition process