Pre-pregnancy obesity and non-adherence to multivitamin use: findings from the National Pregnancy Risk Assessment Monitoring System (2009–2011)

Background Although adequate folic acid or multivitamins can prevent up to 70 % of neural tube defects, the majority of U.S. non-pregnant women of childbearing age do not use multivitamins every day. Factors influencing consistent multivitamin use are not fully explored. This study aims to investigate the association between pre-pregnancy body mass index (BMI) and multivitamin use before pregnancy using a large, nationally representative sample of women with recent live births. Methods The national 2009–2011 Pregnancy Risk Assessment Monitoring System data were analyzed. The sample included women with recent singleton live births (N = 104,211). The outcome of interest was multivitamin use which was categorized as no multivitamin use, 1–3 times/week, 4–6 times/week, and daily use. Maternal BMI was examined as underweight (\u3c18.50 kg/m2), normal weight (18.50–24.99 kg/m2), overweight (25.00–29.99 kg/m2), and obese (≥30.00 kg/m2). Multinomial logistic regression was conducted, and adjusted odds ratios and 95 % confidence intervals were calculated. Results Compared to women with normal weight, overweight and obese women had significantly increased odds of not taking multivitamins after adjusting for confounding factors. Further, the lack of multivitamin use increased in magnitude with the level of BMI (ORoverweight = 1.2, 95 % CI = 1.1–1.3; ORobese = 1.4, 95 % CI = 1.2–1.5). Conclusions Obese and overweight women were less likely to follow the recommendation for preconception multivitamin use compared to normal weight women. All health care professionals must enhance preconception care with particular attention to overweight and obese women. Preconception counseling may be an opportunity to discuss healthy eating and benefits of daily multivitamin intake before pregnancy

Simulation of a phosphene field based visual prosthesis

Journal ArticleA visual prosthesis for the blind based upon electrical stimulation of the visual cortex requires the development of an array of electrodes. To establish design specifications for such an electrode array, we have conducted psychophysical experiments with normally sighted subjects wearing a portable 'phosphene' simulator. The simulator consists of a small video camera, a monitor masked by an opaque perforated film, and optical lenses. The visual angle subtended by the masked monitor is 1.7" or less. We measured visual acuity and reading rate as a function of the number of pixels and their spacing. Our results indicate that a phosphene image produced by 600 electrodes implanted in a 1 cmz area near the foveal projection on the visual cortex should provide a limited but useful visual sense for the profoundly blind

Postpartum Visit Attendance Increases the Use of Modern Contraceptives

Background. Delays in postpartum contraceptive use may increase risk for unintended or rapid repeat pregnancies. The postpartum care visit (PPCV) is a good opportunity for women to discuss family planning options with their health care providers. This study examined the association between PPCV attendance and modern contraceptive use using data from a managed care organization. Methods. Claims and demographic and administrative data came from a nonprofit managed care organization in Virginia (2008–2012). Information on the most recent delivery for mothers with singleton births was analyzed (N = 24,619). Routine PPCV (yes, no) and modern contraceptive use were both dichotomized. Descriptive analyses provided percentages, frequencies, and means. Multiple logistic regression was conducted and ORs and 95% CIs were calculated. Results. More than half of the women did not attend their PPCV (50.8%) and 86.9% had no modern contraceptive use. After controlling for the effects of confounders, women with PPCV were 50% more likely to use modern contraceptive methods than women with no PPCV (OR = 1.50, 95% CI = 1.31, 1.72). Conclusions. These findings highlight the importance of PPCV in improving modern contraceptive use and guide health care policy in the effort of reducing unintended pregnancy rates

BRST Quantization of the Proca Model based on the BFT and the BFV Formalism

The BRST quantization of the Abelian Proca model is performed using the Batalin-Fradkin-Tyutin and the Batalin-Fradkin-Vilkovisky formalism. First, the BFT Hamiltonian method is applied in order to systematically convert a second class constraint system of the model into an effectively first class one by introducing new fields. In finding the involutive Hamiltonian we adopt a new approach which is more simpler than the usual one. We also show that in our model the Dirac brackets of the phase space variables in the original second class constraint system are exactly the same as the Poisson brackets of the corresponding modified fields in the extended phase space due to the linear character of the constraints comparing the Dirac or Faddeev-Jackiw formalisms. Then, according to the BFV formalism we obtain that the desired resulting Lagrangian preserving BRST symmetry in the standard local gauge fixing procedure naturally includes the St\"uckelberg scalar related to the explicit gauge symmetry breaking effect due to the presence of the mass term. We also analyze the nonstandard nonlocal gauge fixing procedure.Comment: 29 pages, plain Latex, To be published in Int. J. Mod. Phys.

High Performance Electrocatalysts Based on Pt Nanoarchitecture for Fuel Cell Applications

Fuel cells, converting chemical energy from fuels into electricity directly without the need for combustion, are promising energy conversion devices for their potential applications as environmentally friendly, energy efficient power sources. However, to take fuel cell technology forward towards commercialization, we need to achieve further improvements in electrocatalyst technology, which can play an extremely important role in essentially determining cost-effectiveness, performance, and durability. In particular, platinum- (Pt-) based electrocatalyst approaches have been extensively investigated and actively pursued to meet those demands as an ideal fuel cell catalyst due to their most outstanding activity for both cathode oxygen reduction reactions and anode fuel oxidation reactions. In this review, we will address important issues and recent progress in the development of Pt-based catalysts, their synthesis, and characterization. We will also review snapshots of research that are focused on essential dynamics aspects of electrocatalytic reactions, such as the shape effects on the catalytic activity of Pt-based nanostructures, the relationships between structural morphology of Pt-based nanostructures and electrochemical reactions on both cathode and anode electrodes, and the effects of composition and electronic structure of Pt-based catalysts on electrochemical reaction properties of fuel cells.</jats:p

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