990 research outputs found
The etiology of esophageal cancer in high- and low- risk areas of Jiangsu province, China
No full text [Background]Esophageal cancer (EC) remains one of the most common and fatal malignancies worldwide. The geographic variation in EC occurrence is striking, and China is an area with one of the highest incidences of EC. A number of epidemiological studies have been conducted toward EC in the past decades, results suggested that tobacco smoking, alcohol drinking, unhealthy dietary factors and chronic injuries of the esophageal mucosa are important in the development of this disease. Genetic polymorphisms in enzymes involved in metabolism of carcinogens may also influence individual susceptibility. However, the effects of major lifestyle and hereditary risk factors on the development of EC remain poorly understood in China. Moreover, little attention has been paid to the etiological heterogeneity between similar areas with great risk gradient. [Methods]From 2003 to 2007, a large population-based case-control study of EC has been conducted in a selected high-risk area and a selected low-risk area of Jiangsu Province, one of the highest cancer incidence areas in China. In total, 1,520 cases and 3,879 controls were recruited. In this thesis, we evaluated the role of major lifestyle factors such as tobacco smoking, alcohol drinking and dietary factors, as well as inherited determinants including family history of cancer and genetic polymorphisms of alcohol-metabolizing related genes on the risk of EC. In addition, we investigated how much of the risk gradient between two areas could be explained by variation in the distributions of major risk factors. [Results] Tobacco smoking and alcohol drinking moderately increased the risk of EC, while the positive associations were only found among men but not among women. Dietary factors were observed to play important roles in the development of EC. Specific dietary habits i.e., fast eating speed, and hot eating and/or drinking substantially elevated EC risk and could explain more than 20% of EC cases each. High intake of salty foods and fried foods, low consumption of raw garlic were also observed to increase the risk of EC. In addition to environmental and lifestyle factors, we confirmed that a positive family history can significantly increase EC risk, and found the inheritance may modify the effect of some unhealthy lifestyles. Moreover, we further explored the relationship between EC and single nucleotide polymorphismsof ADH1B, ADH1C and ALDH2 genes. Results showed that the slow metabolizing ADH1B G allele, ADH1C G allele and ALDH2 A allele significantly increased EC risk among moderate-to-heavy alcohol drinkers, and a significant interaction was observed between ALDH2 gene and alcohol consumption. Lastly, we found that more than 60% of EC cases could be attributable to major lifestyle risk factors in the study population; furthermore, dissimilar distribution of several lifestyle factors, together with variations of hereditary factors may be largely responsible for the incidence difference between two study areas. [Conclusion]The findings in this thesis confirm that unhealthy lifestyles including smoking, alcohol drinking and some dietary factors are the predominant risk factors of EC in China, and a large proportion of incidence difference between regions at varying risk could be attributed to the different prevalence of lifestyle factors. As most of the identified risk factors are modifiable, these could be translated into risk reduction prevention programs in China, and a substantial proportion of new EC cases are expected to be prevented by eliminating or avoiding these risk factors in the population. </p
Quantitative strain analysis of misfit dislocations in a Ge/Si heterostructure interface by geometric phase analysis
No full textMicrobiome profiling reveals a microbial dysbiosis during a natural outbreak of tenacibaculosis (Yellow Mouth) in Atlantic salmon
No full textTenacibaculosis remains a major health issue for a number of important aquaculture species globally. On the west coast of Canada, yellow mouth (YM) disease is responsible for significant economic loss to the Atlantic salmon industry. While Tenacibaculum maritimum is considered to be the primary agent of clinical YM, the impact of YM on the resident microbial community and their influence on the oral cavity is poorly understood. Using a 16s rRNA amplicon sequencing analysis, the present study demonstrates a significant dysbiosis and a reduction in diversity of the microbial community in the YM affected Atlantic salmon. The microbial community of YM affected fish was dominated by two amplicon sequence variants (ASVs) of T. maritimum, although other less abundant ASVs were also found. Interestingly clinically unaffected (healthy) and YM surviving fish also had a high relative abundance of T. maritimum, suggesting that the presence of T. maritimum is not solely responsible for YM. A statistically significant association was observed between the abundance of T. maritimum and increased abundance of Vibrio spp. within fish displaying clinical signs of YM. Findings from our study provide further evidence that YM is a complex multifactorial disease, characterized by a profound dysbiosis of the microbial community which is dominated by distinct ASVs of T. maritimum. Opportunistic taxa, including Vibrio spp., may also play a role in clinical disease progression.Commonwealth Scientific and Industrial Research OrganisationCanada Excellence Research ChairsUniversity of Prince Edward Islan
A class of Frattini-like subgroups of a finite group
No full textAbstractLet G be a finite group and π a set of primes. We consider the families of subgroups of G:F1 = {M: M ⋖ G, |G : M|π = 1}F2 = {M: M ⋖ G, |G : M|π = 1, |G : M| is composite}. Denote Φπ(G) = ∩ {M: M ϵ F1} if F1 is nonempty, otherwise Φπ(G) = G and Sπ (G) = ∩ {M: M ϵ F2} if F2 is nonempty, otherwise Sπ(G) = G. The purpose of this paper is to investigate these subgroups further
Quantitative strain characterization of SiGe heterostructures by high-resolution transmission electron microscopy
No full textWe report the quantitative strain characterization in semiconductor heterostructures of silicon-germaniums (Si(0.76)Geo(0.24)) grown on Si substrate by an ultra-high vacuum chemical vapor deposition system. The relaxed SiGe virtual substrate has been achieved by thermal annealing of the SiGe film with an inserted Ge layer. Strain analysis was performed using a combination of high-resolution transmission electron microscopy and geometric phase analysis
Resonant coupling of a SQUID to a mechanical resonator
No full textWe analyze the properties of a mechanical resonator embedded into a quantum SQUID and analyze under which conditions it is possible to realize a resonant coupling between the SQUID and the resonator. We find, within the present technology, how it is possible to tune the system into the regime where the plasma frequency of the SQUID matches the resonator frequency and maximizes the corresponding coupling. In these conditions the doubly degenerate quantum level of the system is split by the coupling between the SQUID and the resonator.QN/Quantum NanoscienceApplied Science
Detecting phonon blockade with photons
No full textMeasuring the quantum dynamics of a mechanical system, when few phonons are involved, remains a challenge. We show that a superconducting microwave resonator linearly coupled to the mechanical mode constitutes a very powerful probe for this scope. This new coupling can be much stronger than the usual radiation pressure interaction by adjusting a gate voltage. We focus on the detection of phonon blockade, showing that it can be observed by measuring the statistics of the light in the cavity. The underlying reason is the formation of an entangled state between the two resonators. Our scheme realizes a phonotonic Josephson junction, giving rise to coherent oscillations between phonons and photons as well as a self-trapping regime for a coupling smaller than a critical value. The transition from the self-trapping to the oscillating regime is also induced dynamically by dissipation.QN/Quantum NanoscienceApplied Science
Predicting angular-momentum waves based on Yang–Mills equations
No full textAs one of the most elegant theories in physics, Yang–Mills (YM) theory not only incorporates Maxwell’s equations unifying electromagnetism, but also underpins the standard model explaining the electroweak and strong interactions in a succinct way. Whereas the highly nonlinear terms in YM equations involving the interactions between potentials and fields retard the resolution for them. In the U(1) case, the solutions of Maxwell’s equations are the electromagnetic waves, which have been applied extensively in the modern communication networks all over the world. Likewise the operator solutions of the YM equations under the assumptions of weak-coupling and zero-coupling predict the SU(2) angular-momentum waves, which is the staple of this work. Such angular-momentum waves are hopefully realized in the experiments through the oscillation of spin angular momentum, such as the “spin Zitterbewegung” of Dirac’s electron
Improving the engineering strength of heat strengthened glass
No full textAlthough glass is increasingly used as a structural material, glass is not produced to strength standards, like steel and concrete. Of the three types of glass: annealed, heat strengthened and fully tempered, only heat strengthened glass has the properties to function as a safe structural material. These properties are strength, resistance to stress corrosion cracking, and controlled fragmentation. In this paper the factors controlling the strength of heat strengthened glass are assessed. The dominant influence is the spread in compressive pre-strength. Opportunities for quality control of the compressive pre-strength are analysed using experimental results. The consequences for the predictability of the strength and the requirements for quality controlled are discussed
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