76 research outputs found

    Anti-müllerian hormone is not associated with cardiometabolic risk factors in adolescent females

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    <p>Objectives: Epidemiological evidence for associations of Anti-Müllerian hormone (AMH) with cardiometabolic risk factors is lacking. Existing evidence comes from small studies in select adult populations, and findings are conflicting. We aimed to assess whether AMH is associated with cardiometabolic risk factors in a general population of adolescent females.</p> <p>Methods: AMH, fasting insulin, glucose, HDLc, LDLc, triglycerides and C-reactive protein (CRP) were measured at a mean age 15.5 years in 1,308 female participants in the Avon Longitudinal Study of Parents and Children (ALSPAC). Multivariable linear regression was used to examine associations of AMH with these cardiometabolic outcomes.</p> <p>Results: AMH values ranged from 0.16–35.84 ng/ml and median AMH was 3.57 ng/ml (IQR: 2.41, 5.49). For females classified as post-pubertal (n = 848) at the time of assessment median (IQR) AMH was 3.81 ng/ml (2.55, 5.82) compared with 3.25 ng/ml (2.23, 5.05) in those classed as early pubertal (n = 460, P≤0.001). After adjusting for birth weight, gestational age, pubertal stage, age, ethnicity, socioeconomic position, adiposity and use of hormonal contraceptives, there were no associations with any of the cardiometabolic outcomes. For example fasting insulin changed by 0% per doubling of AMH (95%CI: −3%,+2%) p = 0.70, with identical results if HOMA-IR was used. Results were similar after additional adjustment for smoking, physical activity and age at menarche, after exclusion of 3% of females with the highest AMH values, after excluding those that had not started menarche and after excluding those using hormonal contraceptives.</p> <p>Conclusion: Our results suggest that in healthy adolescent females, AMH is not associated with cardiometabolic risk factors.</p&gt

    Follicle Stimulating Hormone and Anti-Müllerian Hormone per Oocyte in Predicting in vitro Fertilization Pregnancy in High Responders: A Cohort Study

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    Background: Follicle stimulating hormone (FSH) and Anti-Müllerian hormone (AMH) are utilized to differentiate between good and poor response to controlled ovarian hyperstimulation. Their respective roles in defining functional ovarian reserve remain, however, to be elucidated. To better understand those we investigated AMH and FSH per oocyte retrieved (AMHo and FSHo). Methodology/Principal Findings: Three-hundred and ninety-six women, undergoing first in vitro fertilization cycles, were retrospectively evaluated. Women with oocyte yields.75 th percentile for their age group were identified as high responders. In a series of logistic regression analyses, AMHo and FSHo levels were then evaluated as predictive factors for pregnancy potential in high responders. Patients presented with a mean age of 38.065.0 years, mean baseline FSH of 11.868.7 mIU/mL and mean AMH of 1.662.1 ng/mL. Those 88 women, who qualified as high responders, showed mean FSH of 9.766.5 mIU/mL, AMH of 3.163.1 ng/mL and oocyte yields of 15.867.1. Baseline FSH and AMH did not predict pregnancy in high responders. However, a statistically significant association between FSHo and pregnancy was observed in high responders, both after univariate regression (p = 0.02) and when adjusted for age, percentage of usable embryos, and number of embryos transferred (p = 0.03). Rate of useable embryos also significantly affected pregnancy outcome independently of FSHo (p = 0.01). AMHo was also associated with clinical pregnancy chances in high responders (p = 0.03

    Gamma Attenuation Behavior of Some Stainless and Boron Steels

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    In the present work gamma attenuation behavior of some commonly used commercial stainless steels and boron steels were investigated. 303, 304, 310, 316, 430 stainless steels and ZF7B, 27M12C5B, 30MNB5 boron steels were studied against Cs-137 and Co-60 gamma radioisotopes. The linear and mass attenuation coefficients of the samples were measured by using gamma transmission technique. Mass attenuation coefficients were compared with the theoretical values which were calculated by using XCOM computer code. Theoretical and experimental mass attenuations were closed to each other. In addition half-value thickness (HVT) values of the samples were calculated and compared with the results of lead (Pb). European Union has published the directive in 2002 and recast in 2011 about Restriction of Some Hazardous Substances (RoHS) which included Pb. This study shows that 303, 304, 310 and 316 stainless steels and ZF7B, 27M12C5B, 30MNB5 boron steels are some of the candidate materials for using in gamma shielding applications instead of lead

    Comparison of Lead and WC-Co Materials against Gamma Irradiation

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    According to RoHS (Restriction of Hazardous Substances) directive of European Union it is restricted using lead in many equipment and applications. It is possible to enlarge the restriction of lead usage in some other applications which is including some of nuclear applications in the future. Therefore new materials or systems need to be developed instead of lead as radiation shielding materials and/or collimators. In this study pure tungsten, tungsten carbide-cobalt (WC-Co) materials were investigated against gamma radiation. For gamma radiation Cs-137 and Co-60 gamma radioisotope sources were used. The linear and mass attenuations were calculated. The experimental results were compared with XCOM computer code. Usage possibilities of WC-Co instead of lead in nuclear applications as gamma shielding material were discussed. It has been investigated that the linear gamma attenuation coefficients of lead and WC-Co are very close to each other. Therefore it could be said that WC-Co materials is an alternative promising material which could be used instead of lead as gamma shielding material and/or collimator

    Investigation of Gamma Ray and Neutron Attenuation Coefficients for Granites Produced in Turkey

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    In this study, shielding properties of granites which are produced in Turkey were studied for gamma ray and neutrons. Linear and mass attenuation coefficients for gamma ray were measured at 1.17 MeV, 1.33 MeV and 0.662 MeV by gamma spectrometry system containing NaI(Tl) detector. Pu-Be source was used in measuring linear neutron attenuation coefficients of the granite samples. Measurements were carried out by using narrow beam geometry by using gamma and neutron transmission technique. The gamma transmission results have been compared with winXCOM calculations and a good correspondence has been obtained

    Investigation of Gamma Ray and Neutron Attenuation Coefficients for Granites Produced in Turkey

    No full text
    In this study, shielding properties of granites which are produced in Turkey were studied for gamma ray and neutrons. Linear and mass attenuation coefficients for gamma ray were measured at 1.17 MeV, 1.33 MeV and 0.662 MeV by gamma spectrometry system containing NaI(Tl) detector. Pu-Be source was used in measuring linear neutron attenuation coefficients of the granite samples. Measurements were carried out by using narrow beam geometry by using gamma and neutron transmission technique. The gamma transmission results have been compared with winXCOM calculations and a good correspondence has been obtained

    Evaluation of Gamma Penetration through Plain Carbon Steels

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    In this study, 1010, 1040, 1050 and 1090 carbonized steels were investigated against gamma radioisotope sources on their gamma attenuation properties. Co-60, Cs-137 and Ir-192 gamma radioisotopes which are commonly used in industrial applications were used in the experiments. Half-value layers were carried out for studied carbonized steels against all studied gamma radioisotopes. In addition, the linear and mass attenuation coefficients were determined for each carbonized steels at different gamma radioisotope sources. The theoretical mass attenuation coefficients were calculated from XCOM computer code for all samples at specific energies of Co-60, Cs-137 and Ir-192 gamma sources. The theoretical and experimental results were compared with each other

    Evaluation of Gamma Penetration through Plain Carbon Steels

    No full text
    In this study, 1010, 1040, 1050 and 1090 carbonized steels were investigated against gamma radioisotope sources on their gamma attenuation properties. Co-60, Cs-137 and Ir-192 gamma radioisotopes which are commonly used in industrial applications were used in the experiments. Half-value layers were carried out for studied carbonized steels against all studied gamma radioisotopes. In addition, the linear and mass attenuation coefficients were determined for each carbonized steels at different gamma radioisotope sources. The theoretical mass attenuation coefficients were calculated from XCOM computer code for all samples at specific energies of Co-60, Cs-137 and Ir-192 gamma sources. The theoretical and experimental results were compared with each other

    Investigation on the Effects of Boron Carbide Particle Size on Radiation Shielding Properties of Boron Carbide-Titanium Diboride Composites

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    Boron carbide is a material which has wide application areas in industry including nuclear technology. Titanium diboride-boron carbide composites which were produced from different boron carbide particle sizes were studied for searching of the behaviour against the gamma ray. Micron size and submicron size boron carbide were used to produce composite materials. The volume of boron carbide and titanium diboride in the composites are 85% and 15%, respectively. For the investigation of the gamma radiation behaviour of these materials, Cs-137 radioisotope was used as gamma source in the experiments which has a single gamma-peak at 0.662 MeV. Gamma transmission technique was used for the measurements. The effects of boron carbide particle size on radiation attenuation of titanium diboride-boron carbide composites were evaluated in relation with gamma transmission and the results of the experiments were interpreted and compared with each other. It could be understood that decrease of particle size of boron carbide in boron carbide-titanium diboride composites causes higher linear and mass attenuation coefficient values. So, submicron size boron carbide used composite materials are more convenient than micron size boron carbide used composite materials as radiation shielding materials for nuclear applications
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