61 research outputs found
Peculiarities of gamma-quanta distribution at 20 TeV energy
The angular distribution of protons from the fragmentational region is analyzed. The gamma-quanta families are generated in a dense target by cosmic ray particles at 20 Tev energy. Families were found which had dense groups (spikes) of gamma-quanta where the rapidity/density is 3 times more than the average value determined for all registered families. The experimental data is compared with the results of artificial families simulation
Factors that contribute to faecal cyclooxygenase-2 mRNA expression in subjects with colorectal cancer
æ”æŸć»ç§ć€§ćŠćŠäœè«æăć»ć珏600ć·ïŒćčłæ23ćčŽ3æ16æ„
The Int7G24A variant of transforming growth factor-beta receptor type I is a risk factor for colorectal cancer in the male Spanish population: a case-control study
Background: The Int7G24A variant of transforming growth factor-beta receptor type I (TGFBR1) has been shown to increase the risk for kidney, ovarian, bladder, lung and breast cancers. Its role in colorectal cancer (CRC) has not been established. The aims of this study were to assess the association of TGFBR1*Int7G24A variant with CRC occurrence, patient age, gender, tumour location and stage. Methods: We performed a case-control study with 504 cases of sporadic CRC; and 504 non-cancerous age, gender and ethnically matched controls. Genotyping analysis was performed using allelic discrimination assay by real time PCR. Results: The Int7G24A variant was associated with increased CRC incidence in an additive model of inheritance (P for trend = 0.005). No significant differences were found between Int7G24A genotypes and tumour location or stage. Interestingly, the association of the Int7G24A variant with CRC risk was significant in men (odds ratio 4.10 with 95% confidence intervals 1.41-11.85 for homozygous individuals; P for trend = 0.00023), but not in women. We also observed an increase in susceptibility to CRC for individuals aged less than 70 years. Conclusion: Our data suggest that the Int7G24A variant represents a risk factor for CRC in the male Spanish population.Research supported in part by grants from the Generalitat Valenciana in Spain (AP106/06) and the Biomedical Research Foundation from the Hospital of Elche, Spain (FIBElx-02/2007). T.M-B is recipient of a fellowship from the Spanish Society of Medical Oncology (SEOM)
Genetic variants associated with fasting blood lipids in the U.S. population: Third National Health and Nutrition Examination Survey
<p>Abstract</p> <p>Background</p> <p>The identification of genetic variants related to blood lipid levels within a large, population-based and nationally representative study might lead to a better understanding of the genetic contribution to serum lipid levels in the major race/ethnic groups in the U.S. population.</p> <p>Methods</p> <p>Using data from the second phase (1991-1994) of the Third National Health and Nutrition Examination Survey (NHANES III), we examined associations between 22 polymorphisms in 13 candidate genes and four serum lipids: high-density lipoprotein cholesterol (HDL-C), low-density lipoprotein cholesterol (LDL-C), total cholesterol (TC), and triglycerides (TG). Univariate and multivariable linear regression and within-gene haplotype trend regression were used to test for genetic associations assuming an additive mode of inheritance for each of the three major race/ethnic groups in the United States (non-Hispanic white, non-Hispanic black, and Mexican American).</p> <p>Results</p> <p>Variants within <it>APOE </it>(rs7412, rs429358), <it>PON1 </it>(rs854560), <it>ITGB3 </it>(rs5918), and <it>NOS3 </it>(rs2070744) were found to be associated with one or more blood lipids in at least one race/ethnic group in crude and adjusted analyses. In non-Hispanic whites, no individual polymorphisms were associated with any lipid trait. However, the <it>PON1 </it>A-G haplotype was significantly associated with LDL-C and TC. In non-Hispanic blacks, <it>APOE </it>variant rs7412 and haplotype T-T were strongly associated with LDL-C and TC; whereas, rs5918 of <it>ITGB3 </it>was significantly associated with TG. Several variants and haplotypes of three genes were significantly related to lipids in Mexican Americans: <it>PON1 </it>in relation to HDL-C; <it>APOE </it>and <it>NOS3 </it>in relation to LDL-C; and <it>APOE </it>in relation to TC.</p> <p>Conclusions</p> <p>We report the significant associations of blood lipids with variants and haplotypes in <it>APOE</it>, <it>ITGB3, NOS3</it>, and <it>PON1 </it>in the three main race/ethnic groups in the U.S. population using a large, nationally representative and population-based sample survey. Results from our study contribute to a growing body of literature identifying key determinants of plasma lipoprotein concentrations and could provide insight into the biological mechanisms underlying serum lipid and cholesterol concentrations.</p
Unexpected diversity in socially synchronized rhythms of shorebirds
The behavioural rhythms of organisms are thought to be under strong selection, influenced by the rhythmicity of the environment. Such behavioural rhythms are well studied in isolated individuals under laboratory conditions, but free-living individuals have to temporally synchronize their activities with those of others, including potential mates, competitors, prey and predators. Individuals can temporally segregate their daily activities (for example, prey avoiding predators, subordinates avoiding dominants) or synchronize their activities (for example, group foraging, communal defence, pairs reproducing or caring for offspring). The behavioural rhythms that emerge from such social synchronization and the underlying evolutionary and ecological drivers that shape them remain poorly understood. Here we investigate these rhythms in the context of biparental care, a particularly sensitive phase of social synchronization where pair members potentially compromise their individual rhythms. Using data from 729 nests of 91 populations of 32 biparentally incubating shorebird species, where parents synchronize to achieve continuous coverage of developing eggs, we report remarkable within-and between-species diversity in incubation rhythms. Between species, the median length of one parent's incubation bout varied from 1-19 h, whereas period length-the time in which a parent's probability to incubate cycles once between its highest and lowest value-varied from 6-43 h. The length of incubation bouts was unrelated to variables reflecting energetic demands, but species relying on crypsis (the ability to avoid detection by other animals) had longer incubation bouts than those that are readily visible or who actively protect their nest against predators. Rhythms entrainable to the 24-h light-dark cycle were less prevalent at high latitudes and absent in 18 species. Our results indicate that even under similar environmental conditions and despite 24-h environmental cues, social synchronization can generate far more diverse behavioural rhythms than expected from studies of individuals in captivity. The risk of predation, not the risk of starvation, may be a key factor underlying the diversity in these rhythms.</p
NAT1 and NAT2 genetic polymorphisms and environmental exposure as risk factors for oesophageal squamous cell carcinoma: a case-control study
Abstract
Background
Tobacco smoking and red meat consumption are some of the known risk factors associated with the development of oesophageal cancer. N-acetytransferases (NAT1 and NAT2) play a key role in metabolism of carcinogenic arylamines present in tobacco smoke and overcooked red meat. We hypothesized that NAT1 and NAT2 genetic polymorphisms may influence the risk of oesophageal cancer upon exposure to environmental carcinogens.
Methods
Single nucleotide polymorphisms (SNPs) in the NAT1 and NAT2 genes were investigated by genotyping 732 cases and 768 healthy individuals from two South African populations to deduce the acetylator phenotype (slow, intermediate or rapid) from the combination of the genotyped SNPs.
Results
The 341 CC genotype (rs1801280) was significantly associated with a reduced risk for oesophageal cancer in the Mixed Ancestry population (ORâ=â0.31; 95% CI 0.11-0.87). The NAT2 slow/intermediate acetylator status significantly increased the risk among cigarette smokers in the Black population (ORâ=â2.76; 95% CI 1.69-4.52), as well as among alcohol drinkers in the Mixed Ancestry population (ORâ=â2.77; 95% CI 1.38-5.58). Similarly, the NAT1 slow/intermediate acetylator status was a risk factor for tobacco smokers in the Black population (ORâ=â3.41; 95% CI 1.95-5.96) and for alcohol drinkers in the Mixed Ancestry population (ORâ=â3.41; 95% CI 1.70-6.81). In a case-only analysis, frequent red meat consumption was associated with a significantly increased cancer risk for NAT2 slow/intermediate acetylators in the Mixed Ancestry population (ORâ=â3.55; 95% CI 1.29-9.82;âPâ=â0.019), whereas daily white meat intake was associated with an increased risk among NAT1 slow/intermediate acetylators in the Black population (ORâ=â1.82; 95% CI 1.09-3.04; Pâ=â0.023).
Conclusions
Our findings indicate that N-acetylation polymorphisms may modify the association between environmental risk factors and oesophageal cancer risk and that N-acetyltransferases may play a key role in detoxification of carcinogens. Prevention strategies in lifestyle and dietary habits may reduce the incidence of oesophageal cancer in high-risk populations
Unexpected diversity in socially synchronized rhythms of shorebirds
The behavioural rhythms of organisms are thought to be under strong selection, influenced by the rhythmicity of the environment1, 2, 3, 4. Such behavioural rhythms are well studied in isolated individuals under laboratory conditions1, 5, but free-living individuals have to temporally synchronize their activities with those of others, including potential mates, competitors, prey and predators6, 7, 8, 9, 10. Individuals can temporally segregate their daily activities (for example, prey avoiding predators, subordinates avoiding dominants) or synchronize their activities (for example, group foraging, communal defence, pairs reproducing or caring for offspring)6, 7, 8, 9, 11. The behavioural rhythms that emerge from such social synchronization and the underlying evolutionary and ecological drivers that shape them remain poorly understood5, 6, 7, 9. Here we investigate these rhythms in the context of biparental care, a particularly sensitive phase of social synchronization12 where pair members potentially compromise their individual rhythms. Using data from 729 nests of 91 populations of 32 biparentally incubating shorebird species, where parents synchronize to achieve continuous coverage of developing eggs, we report remarkable within- and between-species diversity in incubation rhythms. Between species, the median length of one parentâs incubation bout varied from 1â19âh, whereas period lengthâthe time in which a parentâs probability to incubate cycles once between its highest and lowest valueâvaried from 6â43âh. The length of incubation bouts was unrelated to variables reflecting energetic demands, but species relying on crypsis (the ability to avoid detection by other animals) had longer incubation bouts than those that are readily visible or who actively protect their nest against predators. Rhythms entrainable to the 24-h lightâdark cycle were less prevalent at high latitudes and absent in 18 species. Our results indicate that even under similar environmental conditions and despite 24-h environmental cues, social synchronization can generate far more diverse behavioural rhythms than expected from studies of individuals in captivity5, 6, 7, 9. The risk of predation, not the risk of starvation, may be a key factor underlying the diversity in these rhythms
Temporal Resolution of Input Weather Data Strongly Affects an Off-Grid PV System Layout and Reliability
Renewable energy systems design using average year weather data is a standard approach that works well for grid-tied systems, but for stand-alone ones, it leads to dramatic mistakes. We considered the effect of meteorological data temporal resolution (5, 10, 15, 20, 30 min; 1, 2, 3, 4 h) on a stand-alone hybrid system’s layout in terms of equipment cost, power supply reliability and maximum duration of interruption for monitoring equipment in the Alps. We have shown that lifecycle costs could be strongly (order of magnitude) underestimated for off-grid systems, as well as their reliability overestimated. Lower temporal resolution data lead to the underestimation of energy storage charge–discharge cycles (considering depth of discharge too)—real batteries are to be replaced more often, which matches our practical experience as well. Even a 5 to 10 min decrease in weather data temporal resolution leads to the estimated annual expenses being halved. In general, we recommend using 30 min resolution
- âŠ