82 research outputs found
Information storing by biomagnetites
Since the discovery of the presence of biogenic magnetites in living
organisms, there have been speculations on the role that these biomagnetites
play in cellular processes. It seems that the formation of biomagnetite
crystals is a universal phenomenon and not an exception in living cells. Many
experimental facts show that features of organic and inorganic processes could
be indistinguishable at nanoscale levels. Living cells are quantum "devices"
rather than simple electronic devices utilizing only the charge of conduction
electrons. In our opinion, due to their unusual biophysical properties, special
biomagnetites must have a biological function in living cells in general and in
the brain in particular. In this paper we advance a hypothesis that while
biomagnetites are developed jointly with organic molecules and cellular
electromagnetic fields in cells, they can record information about the Earth's
magnetic vector potential of the entire flight in migratory birds.Comment: 17 pages, 3 figure
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
Multi-ancestry genome-wide association meta-analysis of Parkinson’s disease
\ua9 2023, This is a U.S. Government work and not under copyright protection in the US; foreign copyright protection may apply. Although over 90 independent risk variants have been identified for Parkinson’s disease using genome-wide association studies, most studies have been performed in just one population at a time. Here we performed a large-scale multi-ancestry meta-analysis of Parkinson’s disease with 49,049 cases, 18,785 proxy cases and 2,458,063 controls including individuals of European, East Asian, Latin American and African ancestry. In a meta-analysis, we identified 78 independent genome-wide significant loci, including 12 potentially novel loci (MTF2, PIK3CA, ADD1, SYBU, IRS2, USP8, PIGL, FASN, MYLK2, USP25, EP300 and PPP6R2) and fine-mapped 6 putative causal variants at 6 known PD loci. By combining our results with publicly available eQTL data, we identified 25 putative risk genes in these novel loci whose expression is associated with PD risk. This work lays the groundwork for future efforts aimed at identifying PD loci in non-European populations
Predicting the tensile strength, impact toughness, and hardness of friction stir-welded AA6061-T6 using response surface methodology
In this research, an attempt has been made to develop mathematical models for predicting mechanical properties including ultimate tensile strength, impact toughness, and hardness of the friction stir-welded AA6061-T6 joints at 95 % confidence level. Response surface methodology with central composite design having four parameters and five levels has been used. The four parameters considered were tool pin profile, rotational speed, welding speed, and tool tilt angle. Three confirmation tests were performed to validate the empirical relations. In addition, the influence of the process parameters on ultimate tensile strength, impact toughness, and hardness were investigated. The results indicated that tool pin profile is the most significant parameter in terms of mechanical properties; tool with simple cylindrical pin profile produced weld with high ultimate tensile strength, impact toughness, and hardness. In addition to tool pin profile, rotational speed was more significant compared to welding speed for ultimate tensile strength and impact toughness, whereas welding speed showed dominancy over rotational speed in case of hardness. Optimum conditions of process parameters have been found at which tensile strength of 92 %, impact toughness of 87 %, and hardness of 95 % was achieved in comparison to the base metal. This research will contribute to expand the scientific foundation of friction stir welding of aluminum alloys with emphasis on AA6061-T6. The results will aid the practitioners to develop a clear understanding of the influence of process parameters on mechanical properties and will allow the selection of best combinations of parameters to achieve desired mechanical properties
Investigation of enterocolitis incidence due to Clostridium Difficile from the referred to Tehran hospitals
Pseudomembrane colitis (PMC) and antibiotic associated colitis (AAC) are acute disease of the colon. In the case of in adequate treatment, the disease will often become chronic and my lead to the dysplasia of the epithelial cells of the infected areas. Previously because of poor knowledge. Treatment in this case, one of the method for treatment was surgical ablation of the large intestine while the patients could have been treated with oral vancomycin. In this study the following results were obtained: Out of 2517 enterocolitis patients under study, 1384 were men and 1133 women. By anaerobic culture method, 132 cases C.Difficile were isolated from the total samples and Hela cell culture method, toxin was determined in 36 samples (1.43%)
Evaluating the effect of Die spacer on crown retention in fixed prosthesis
Crown retention is related to its adaptation
with tooth while there is always a gap between the crown and prepared tooth.
Although this gap is filled with cements but the mechanical retention between
axial walls and internal surfaces is decreased. Therefore, what is the relation
between die spacer and crown retention? Does it affect retention? And if so,
what is the best thickness of it? It has been a long time that various
techniques are recommended and used to improve the adaptation of crowns.
According to Fusayama and based on some other researches, it can be concluded
that by using die spacer we can noticeably decrease the thickness of cement and
improve the adaptation of cement. In addition, many studies on thickness and
amount of die spacer concluded that by using die spacers, in %55 of cases crown
retention was increased while in 30% decreased and 10-15% have not changed.
Hence, it seems that using die spacer is generally beneficial and the best
thickness of it according to our research is 2-4 layers that can improve
retention by 41%
"Rate of Chlamydia trachomatis, Mycoplasma hominis and Ureaplasma urealyticum in Infertile Females and Control Group"
Infertility in famale is one of the most important sequela of genital infection with Chlamydia trachomatis, Mycoplasma hominis and Ureaplasma urealyticum. In the present study the frequency of these bacteries was studied in 125 infertile female by direct and indirect immunofluorscence tests and culture method and compared with 250 normal population. Mycoplasma hominis was isolated from 32 (35.6%) of infertile females compare with 18 (7.2%) of normal population. Ureaplasma urealyticum was isolated from 41 (32.8%) of infertile females compare to 48 (19.2%) of normal population. Chlamydia trachomatis was detected by direct IF in 11 (8.8%) of infertile and 2 (0.8%) control group. The antibody titer against D-K serotypes of Chlamydia trachomatis was also measured in both groups of infertile and normal population and a positive titer of 1/16 and above was detected in 26 (20.8%) of infertile cases and in 8 (3.2%) of control group. The rate of Chlamydia trachomatis, Mycoplasma hominis and Ureaplasma urealyticum in case and control groups was significant (respectively P<0.0001, P<0.0001, p= 0.0018)
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