Effective optical properties of absorbing nanoporous and nanocomposite thin films

This paper aims at developing numerically validated models for predicting the through-plane effective index of refraction and absorption index of nanocomposite thin films. First, models for the effective optical properties of such materials are derived from previously reported analysis applying the volume averaging theory (VAT) to the Maxwell's equations. The transmittance and reflectance of nanoporous thin films are computed by solving the Maxwell's equations and the associated boundary conditions at all interfaces using finite element methods. The effective optical properties of the films are retrieved by minimizing the root mean square of the relative errors between the computed and theoretical transmittance and reflectance. Nanoporous thin films made of SiO2 and TiO2 consisting of cylindrical nanopores and nanowires are investigated for different diameters and various porosities. Similarly, electromagnetic wave transport through dielectric medium with embedded metallic nanowires are simulated. The numerical results are compared with predictions from widely used effective property models including (1) the Maxwell-Garnett Theory, (2) the Bruggeman effective medium approximation, (3) the parallel, (4) series, (5) Lorentz-Lorenz, and (6) the VAT models. Very good agreement is found with the VAT model for both the effective index of refraction and absorption index. Finally, the effect of volume fraction on the effective index of refraction and absorption index predicted by the VAT model is discussed. For certain values of wavelengths and volume fractions, the effective index of refraction or absorption index of the composite material can be smaller than that of both the continuous and dispersed phases. These results indicate guidelines for designing nanocomposite materials with desired optical properties

The effect of adopting the IADPSG screening guidelines on the risk profile and outcomes of the gestational diabetes population

Abstract Objective:: To compare characteristics and outcomes of women diagnosed with gestational diabetes mellitus (GDM) by the newer one-step glucose tolerance test and those diagnosed with the traditional two-step method. Research design and methods: This was a retrospective cohort study of women with GDM who delivered in 2010–2011. Data are reported as proportion or median (interquartile range) and were compared using a Chi-square, Fisher's exact or Wilcoxon rank sum test based on data type. Results:: Of 235 women with GDM, 55.7% were diagnosed using the two-step method and 44.3% with the one-step method. The groups had similar demographics and GDM risk factors. The two-step method group was diagnosed with GDM one week later [27.0 (24.0–29.0) weeks versus 26.0 (24.0–28.0 weeks); p = 0.13]. The groups had similar median weight gain per week before diagnosis. After diagnosis, women in the one-step method group had significantly higher median weight gain per week [0.67 pounds/week (0.31–1.0) versus 0.56 pounds/week (0.15–0.89); p = 0.047]. In the one-step method group more women had suspected macrosomia (11.7% versus 5.3%, p = 0.07) and more neonates had a birth weight >4000 g (13.6% versus 7.5%, p = 0.13); however, these differences were not statistically significant. Other pregnancy and neonatal complications were similar. Conclusions:: Women diagnosed with the one-step method gained more weight per week after GDM diagnosis and had a non-statistically significant increased risk for suspected macrosomia. Our data suggest the one-step method identifies women with at least equally high risk as the two-step method

The Effect of a Universal Cervical Length Screening Program on Antepartum Management and Birth Outcomes

Objective: The objective of this study was to evaluate the effect of a universal cervical length screening program on the incidence of antepartum interventions. Study Design This retrospective cohort study included women delivering ≥ 20 weeks of gestation with singleton pregnancies before and after implementing universal cervical length screening. Antepartum interventions included admission for threatened preterm birth, ≥ 2 cervical length measurements, cervical cerclage, neonatology consultation, betamethasone, antibiotic administration for preterm premature rupture of membranes, and tocolysis. Results: There were 1,131 women—506 before the screening program (unexposed) and 625 afterward (exposed). The screening program resulted in significantly more women screened (3.0 vs. 69.9%, p < 0.0001). The exposed group was more likely to undergo ≥ 1 intervention (20.0 vs. 9.5%, p < 0.0001); specifically, admission for threatened preterm birth (3.8 vs. 1.8%, p = 0.04) and ≥ 2 cervical measurements (11.2 vs. 2.0%, p < 0.001). Other interventions were similar between groups (all p ≥ 0.06). Median gestation length was significantly longer in the exposed (39.6 weeks [interquartile, IQR: 38.6–40.4] vs. 39.0 weeks [IQR: 38.0–40.0, p < 0.001]); however, preterm delivery incidence was unaffected (9.4 vs. 10.9%, p = 0.43). Remaining neonatal outcomes were similar (all p ≥ 0.14). Conclusion: Implementing universal cervical length screening significantly increased the proportion of women undergoing ≥ 1 antepartum intervention. With the exception of a modestly prolonged gestation, other outcomes were unaffected

Association between body mass index and pain following transobturator sling

We aimed to prospectively evaluate the association between body mass index (BMI) and development of postoperative-onset pain in women undergoing transobturator midurethral sling procedures. We conducted a prospective, observational cohort study of women undergoing inside-to-out transobturator midurethral sling. At preoperative visit, height, weight, self-reported activity level and baseline pain were documented. At postoperative visits, patients indicated pain location and severity, procedure success, and satisfaction. We used log binomial regression to calculate risk ratios, controlling for potential confounders. For the 129 women included, median age was 50.0 years and BMI was 27.2 kg/m2. Adjusting for age and activity level, overweight and obese women had significantly increased risk of postoperative-onset pain compared to normal BMI women. Overweight women were at 1.70 (95%CI 1.05–2.75) times the risk compared to leaner counterparts, whereas obese women were at 1.76 times the risk (95%CI 1.04–2.89). Neither success nor satisfaction was associated with BMI.Impact statement Over three million midurethral slings have been placed worldwide for the treatment or prevention of stress urinary incontinence. The procedure has been studied in lean, overweight and obese populations, and found to have similar efficacy regardless of BMI. Similarly, the risks of midurethral sling have been well-documented, including the risk of pain after transobturator sling. Little attention has been given to whether this risk of postoperative pain varies based on patient BMI. Our previous work suggesting that leaner patients might be at increased risk of postoperative pain following transobturator sling was limited by the shortcomings of a retrospective study design. In this prospective study, we were able to adjust for age and activity level, finding that higher BMI women were at increased risk of postoperative pain, while reporting similar levels of satisfaction with the procedure. Future research is needed to find what differences in anatomy or physiology can explain this finding. From a clinical standpoint, thorough counselling of all patients but particularly those with elevated BMI, is required so that appropriate expectations regarding recovery can be set preoperatively