Prevalence of vitamin d deficiency amongwomen of reproductive age: A multi centric study in tehran

Background and Objectives: The aim of this study was to determine the prevalence of vitaminDdeficiency among Iranianwomenof reproductive age. Methods: In this multicentric cross-sectional study, 300 women aged 15 - 45 years referring to Tehran branch of Islamic Azad university hospitals from 2013 to 2015 were recruited. The collected data included the demographic characteristics of the participants, including age, body mass index (BMI), parity, and serum level of vitamin D. Serum levels of 25-dihydroxy vitamin D were measured by radioimmunoassay. Vitamin D was defined as deficient < 20 nmol/L, mild 25 nmol/L, moderate 12.5 - 25 nmol/L and severe12.5 nmol/L. Statistical analysis was performed, using Excel software. Results: Amongthe300patients, 257 caseshadvitaminDdeficiency;amongwhom,122 caseshadsevere, 96hadmoderateand38hadmild deficiency. Conclusions: According to the results of this study, only 14.8 of the study population had normal serum vitamin D levels, indicating that the majority of Iranian women in the reproductive age have vitamin D deficiency. © 2016, Shiraz University of Medical Sciences

Hot deformation behavior of a Fe3Al Ta alloy in the B2 order regime

In the present work, the hot deformation behavior and the corresponding microstructure evolution of an Fe 25Al 1.5Ta at. alloy in the B2 phase field were investigated. Uniaxial compression tests were carried out in a strain rate range from 0.0013 s amp; 8722;1 to 1 s amp; 8722;1 and in a temperature range from 800 C to 850 C, where an ordered B2 FeAl matrix phase along with a C14 Fe, Al 2Ta Laves phase was confirmed by X ray diffraction. A dynamic material model was applied to predict the safe and damaging processing windows. The underlying flow softening mechanisms were characterized using scanning electron microscopy and electron backscatter diffraction. The flow stress strain curves mostly showed a broad maximum followed by a slight decrease in stress until a steady stress was reached. The optimum processing window for the studied alloy was located at 850 C 0.0013 s amp; 8722;1, where the e amp; 64259;ciency of power dissipation amp; 951; and strain rate sensitivity m reached 50 and 0.25, respectively. The processing map also showed a domain of amp; 64258;ow instability, resulting from cracking, in the range of lower temperatures and higher strain rates 800 C 1 s amp; 8722;1 . The microstructural analyses confirmed a combination of dynamic recovery DRV and dynamic recrystallization DRX over the entire range of deformation conditions tested. The current study reveals a well suited parameter range to achieve a high degree of hot deformability in Fe Al alloys at significantly lower temperatures than those typically used. This may contribute to optimizing the thermomechanical processing of Fe Al alloys and reducing energy consumption in industrial forging operation

A Lab-Scale Mold Simulator Employing an Optical-Fiber-Instrumented Mold to Characterize Initial Steel Shell Growth Phenomena

A mold simulator was developed to replicate the mold oscillation and casting speed conditions of a continuous caster on the lab scale. A mold was designed incorporating fiber optics to capture internal temperature gradients and transient heat transfer phenomena during the initial solidification of steel. Casting parameters (casting speed, oscillation stroke and oscillation frequency) were investigated using the mold simulator. Solidified steel shells and mold thermal data were collected and characterized after initial solidification to investigate the impacts of mold oscillation on shell growth and mold heat transfer

On the Hot Deformation of a Fe Al Ta Iron Aluminide Prepared via Laser Powder Bed Fusion

In the present work, a combined process of laser powder bed fusion LPBF and hot working in terms of microstructure refinement was investigated for Fe 25Al 1.5Ta alloy samples. Uniaxial compression tests were carried out parallel and perpendicular to the building direction BD at 1000 C, where BCC A2 phase was stable, at a strain rate of 0.0013 s amp; 8722;1. The true stress true strain curves indicated a broad flow stress peak followed by a slight decrease, which is typical for dynamic recrystallization DRX of conventional BCC metals such as ferritic iron. A negligible dependence in the flow stress behavior on the compression direction was observed. DRX initiated at a stress of 18.7 MPa for the sample compressed parallel to the BD, corresponding to a true strain of 0.011, and at 18.1 MPa for the samples compressed normal to the BD, which corresponded to a true strain of 0.010. The microstructural investigations by electron backscatter diffraction EBSD showed that the relatively coarse and elongated grains of the as LPBF builds were significantly refined after hot working. The microstructure of the compressed samples mainly consisted deformed grains. These were fragmented by sub grains bounded by low angle boundaries independent of the compression axis, indicating the occurrence of dynamic recovery DRV during hot working. In addition, a few equiaxed, small grains were observed in the pre existing grain boundaries, which formed due to DRX. Most pores in the as LPBF builds were closed after hot compression, particularly in the central region of the deformed specimens where the compressive stress state is dominant. In summary, hot compression reveals a practical thermomechanical post processing treatment for Fe Al Ta iron aluminides built by LPBF. The hot working refines the epitaxially elongated microstructure of the as LPBF builds by DRV DRX and reduces the porosit

Mechanisms of necklace recrystallization in a BCC Fe Al Ta alloy with strengthening Laves phase precipitates

A necklace structure composed of fine grains formed by dynamic recrystallization was uncommonly observed at the pre existing grain boundaries during the hot compression of a BCC Fe 25Al 1.5Ta alloy containing C14 Fe, Al 2Ta Laves phase precipitates. Two possible mechanisms for necklace formation were proposed; particle stimulated nucleation and grain boundary bulging, depending on whether the original grain boundaries are occupied by C14 particles, or they are free of them. Recrystallization was initiated preferentially around the clusters of large particles at the boundaries containing particles. In contrast, the bulging of the original grain boundaries by strain induced boundary migration was observed as a preliminary stage for necklace formation at the particle free boundaries. The necklace structure expanded into the deformed volume in such a way that low angle subgrain boundaries decorating the necklace layers transformed into grains with increasing deformation strai

Five-Year Follow-Up of Parapapillary Atrophy: The Beijing Eye Study

Purpose: To assess longitudinal changes in parapapillary atrophy in the adult population of Greater Beijing. Methods: The population-based Beijing Eye Study 2006 included 3251 subjects who had participated in the Beijing Eye Study 2001 and returned for re-examination. The mean age was 60.4610.1 years. Using optic disc photographs, we measured parapapillary atrophy which was divided into alpha zone and beta zone. Results: Overall progression rate of alpha zone was seen in 0.660.1 % (95 % confidence interval (CI):0.3,0.9) of the subjects and of beta zone in 8.260.5 % (95%CI:7.2,9.1) of the subjects. In binary regression analysis, rate of progression of alpha zone was significantly associated higher age (P = 0.04) and the co-progression of zone Beta (P,0.001). Rate of progression of beta zone was significantly associated with higher age (P,0.001; odds ratio (OR):1.11;95%CI:1.10,1.14), higher intraocular pressure (P,0.001;OR:1.10;95%CI:1.05,1.14), higher myopic refractive error (P,0.001;OR:0.71; 95%CI:0.67,0.75), rural region of habitation (P = 0.002;OR: 0.58; 95%CI:0.41,0.82), presence of glaucomatous optic nerve damage (P,0.001;OR:2.89; 95%CI:1.62,5.14), co-progression of alpha zone (P,0.001;OR:7.13;95%CI:2.43,20.9), absence of arterial hypertension (P = 0.03;OR: 0.70; 95%CI:0.51,0.96), and thicker central corneal thickness (P = 0.02;OR:1.01;95%CI:1.00,1.01). Subjects with a non-glaucomatous optic nerve damage (n = 22) as compared to the remaining subjects did not vary in the progression rate of alpha zone (0.0 % versus 0.660.1%; P = 1.0) and beta zone (8.260.5 % versus 6.360.6%;P = 1.0)

Determining the Stress Intensity Factor in a Cracked Plate Under Tensile Stresses using the Finite Element Method

: Numerical methods, especially the Finite Element method, are increasingly being used for solving different problems. Due to fact that these methods are approximate, having a good understanding and judgment about the errors and their distribution is very important. Hence education of users of engineering analysis and design software is necessary and inattention to it may result in catastrophe.  As regards this issue, the problem of determining the stress intensity factor in a cracked plate under tensile stresses, by using the finite element method together with error estimation and adaptivity, is the subject of this article. For this purpose, an academic FORTRAN code has been developed which is able to estimate the finite element solution error by using the superconvergent patch stress recovery method. In addition, an adaptive solution with remeshings in each step is carried out to improve the quality of the employed finite element mesh. Comparing the obtained results with the analytical solution, as well as the ANSYS commercial software, it is observed that the employed algorithm for error estimation has a better performance and can be used for determination of the stress intensity factor in complex structures with arbitrary cracks