Quasi-dark resonances with antiferromagnetic order in silicon metasurfaces.

Quasi-dark resonances exhibiting antiferromagnetic order are theoretically investigated in a near-infrared metasurface composed of square slotted rings etched in a thin silicon layer on glass substrate. Access to the quasi-dark mode is achieved by reducing the symmetry of the metasurface according to the findings of a detailed group theory analysis. A thorough finite-element study reveals the key optical properties of the antiferromagnetic order quasi-dark mode, namely resonant wavelengths, quality factors, angular dispersion, and its robustness against optical extinction losses. It is demonstrated that the thickness of the silicon metasurface can adjust the asymmetry degree of the resonant Fano lineshape without affecting substantially its quality factor. Furthermore, tuning of the resonant wavelength can be achieved without significant modification of the Fano lineshape by controlling the angle of incidence of the impinging planewave. Overall, the work presents an all-dielectric, near-infrared metasurface for the excitation of sharp resonances with antiferromagnetic order, which can find use in emerging applications based on this particular configuration of artificial optical magnetism and/or strong field confinement and light-matter interaction.

The relationship between delivery and the PaO2 /FiO2 ratio in COVID-19: a cohort study.

OBJECTIVE: To study the effect of delivery on the pO2 /FiO2 ratio (P/F ratio) in patients with COVID-19-related acute respiratory distress syndrome (ARDS) and to compare characteristics between delivered and undelivered pregnant patients with COVID-19. DESIGN: Retrospective cohort. SETTING: Four hospitals in Houston, Texas. POPULATION: Pregnant patients admitted to the hospital for COVID-19. METHODS: Among patients with ARDS who were delivered during their hospitalisation for COVID-19, linear mixed models were used to investigate time trends before and after delivery of the P/F ratio. Patient characteristics were compared between patients delivered during their hospitalisation for COVID-19 and those discharged undelivered. MAIN OUTCOME MEASURES: The P/F ratio, age, gestational age, length of stay and severity of illness, RESULTS: Between 4 May 2020 and 26 July 2020, a total of 61 pregnant patients were admitted for COVID-19. Baseline characteristics were similar between the study groups. Delivery occurred in 21 (34%) of patients during their hospitalisation for COVID-19. Delivered patients had more severe disease and were admitted at a later gestational age than patients not delivered. Ten of these 21 patients (48%) were delivered preterm; of these, six were delivered due to complications of COVID-19 and four were delivered for obstetric indications. In patients with ARDS who were delivered (n = 17), the P/F ratio had a negative slope that improved after delivery. CONCLUSIONS: COVID-19-related ARDS in pregnancy requires multidisciplinary care and individualised decision-making, but delivery slows the deterioration of the P/F ratio in these patients. TWEETABLE ABSTRACT: Delivery improves the P/F ratio in COVID-19-related ARDS, though individualised delivery management is needed.

Ultrasound and Doppler findings in pregnant women with SARS-CoV-2 infection.

OBJECTIVES: To describe and compare ultrasound and Doppler findings in pregnant women who were positive for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) with findings in those who were SARS-CoV-2-negative, evaluated during the pandemic period. METHODS: In this retrospective case-control study, we analyzed data from 106 pregnant women who tested positive for SARS-CoV-2 at the time of, or within 1 week of, an ultrasound scan between 1 May and 31 August 2020. Scans were either performed for routine fetal evaluation or indicated due to a positive SARS-CoV-2 test. Forty-nine women were symptomatic and 57 were asymptomatic. For comparison, we analyzed data from 103 pregnant women matched for maternal age, parity, body mass index and gestational age at the time of the ultrasound scan. These control women did not report symptoms of SARS-CoV-2 infection at the time of the ultrasound scan or at the time of admission for delivery and had a negative SARS-CoV-2 test at admission for delivery. Fetal biometry, fetal anatomy, amniotic fluid volume and Doppler parameters, including umbilical and fetal middle cerebral artery pulsatility indices, cerebroplacental ratio and biophysical profile (BPP), were evaluated as indicated. Biometric and Doppler values were converted to Z-scores for comparison. Our primary outcome, an adverse prenatal composite outcome (APCO) included any one or more of: small-for-gestational-age (SGA) fetus, oligohydramnios, abnormal BPP, abnormal Doppler velocimetry and fetal death. Comorbidities, delivery information and neonatal outcome were compared between the two groups. RESULTS: Eighty-seven (82.1%) women who were positive for SARS-CoV-2 had a body mass index > 25 kg/m2 . SARS-CoV-2-positive women had a higher prevalence of diabetes (26/106 (24.5%) vs 13/103 (12.6%); P = 0.03), but not of pre-eclampsia (21/106 (19.8%) vs 11/103 (10.7%); P = 0.08), compared with controls. The prevalence of APCO was not significantly different between SARS-CoV-2-positive women (19/106 (17.9%)) and controls (9/103 (8.7%)) (P = 0.06). There were no differences between SARS-CoV-2-positive women and controls in the prevalence of SGA fetuses (12/106 (11.3%) vs 6/103 (5.8%); P = 0.17), fetuses with abnormal Doppler evaluation (8/106 (7.5%) vs 2/103 (1.9%); P = 0.08) and fetuses with abnormal BPP (4/106 (3.8%) vs 0/103 (0%); P = 0.14). There were two fetal deaths in women who were positive for SARS-CoV-2 and these women had a higher rate of preterm delivery ≤ 35 weeks of gestation (22/106 (20.8%) vs 9/103 (8.7%); odds ratio, 2.73 (95% CI, 1.19-6.3); P = 0.01) compared with controls. CONCLUSIONS: There were no significant differences in abnormal fetal ultrasound and Doppler findings observed between pregnant women who were positive for SARS-CoV-2 and controls. However, preterm delivery ≤ 35 weeks was more frequent among SARS-CoV-2-positive women. © 2021 International Society of Ultrasound in Obstetrics and Gynecology.

Prevalence of comorbidities and the prognostic value of the PROFUND index in a hospital cardiology unit. / Prevalencia de pluripatología y valor pronóstico del índice PROFUND en una unidad de hospitalización de Cardiología.

INTRODUCTION: The aim of this study was to understand the prevalence of comorbidities and the usefulness of the PROFUND index for the prognostic stratification of patients with comorbidities in a hospital cardiology unit. PATIENTS AND METHODS: We consecutively analysed all patients hospitalized in 2012 in the department of cardiology. We recorded the comorbidities, length of stay, hospital mortality, Charlson indices and PROFUND indices. In the patients with comorbidities, we also recorded the readmissions and mortality during a 1-year follow-up. RESULTS: The study included 1,033 patients (mean age, 67±13.1 years; 35% women), 381 (36.9%) of whom had comorbidities, with a mean Charlson index of 6.4±1.7 and a mean PROFUND index of 2.5±2.5. Compared with the other patients, the patients with comorbidities were older (72 vs. 64 years, p<.001), had a higher mortality rate (2.9% vs. 1.1%, p=.046) and longer hospital stays (8±5.5 vs. 6±5.7 days, p<.001) and were more often admitted for heart failure (42.3% vs. 15.8%, p<.001). The PROFUND index was independently associated with overall mortality (hazard ratio [HR], 1.13; 95% CI: 1.01-1.27; p=.034) and with the presence of major adverse events during the 12-month follow-up (HR, 1.09; 95% CI: 1.01-1.18; p=.026). CONCLUSIONS: A high percentage of patients hospitalized in the department of cardiology had comorbidities. These patients had a higher prevalence of cardiovascular risk factors, longer stays and greater hospital mortality. The PROFUND index independently predicted mortality and adverse events during the follow-up.

Experiencia preliminar en el uso del registro de fertilidad en una cohorte de pacientes de infertilidad en un servicio de ginecología y obstetricia / Preliminary experience in the use of fertility charting in a cohort of infertility patients at a department of obstetrics and gynecology / Experiência preliminar no uso do registro de fertilidade em um coorte de pacientes de infertilidade num serviço de ginecologia e obstetrícia

Objetivo: estudiar los resultados de las pacientes con infertilidad tratadas con un enfoque de medicina restaurativa (naprotecnología) en un servicio de ginecología y obstetricia. Metodología: estudio de cohorte retrospectivo realizado por el departamento de obstetricia y ginecología de la Universidad de los Andes (Santiago, Chile) en pacientes con infertilidad de un área suburbana de Santiago de Chile, que recibieron tratamiento entre el 2006 y 2014. Todas las parejas recibieron instrucción para reconocer su período de fertilidad según un modelo local de enseñanza, basado en el modelo Creigthon (Creigthon Model FertilityCare System). Recibieron, además, tratamiento médico para inducción de ovulación, mejoramiento del período fértil o cirugía reparadora. La medición primaria fue el número de embarazos. Resultados: 131 pacientes recibieron la instrucción. El promedio de edad fue de 33.6 años. 78 pacientes (59.5%) consultaron por infertilidad primaria; 53 (40.5%), infertilidad secundaria. El tiempo de infertilidad del grupo fue de 4.1 años. El promedio de uso del método fue de 12.6 meses (mediana, 9 meses). Las causas de infertilidad identificadas fueron anovulación (50.4%), tubo-peritoneal (18.3%), endometriosis (14.5%), uterino (9.2%), cervical (8.4%) y masculino (19.1%). Hubo 33 embarazos (25.2 global). La proporción cruda de embarazos a los 24 meses fue de 22.9% y la ajustada por tabla de vida a los 24 meses fue de 40 por 100 parejas. Conclusiones: el enfoque de medicina restaurativa es efectivo para lograr embarazos pero requiere de un manejo longitudinal a largo plazo. El abandono temprano del uso del registro de fertilidad afecta la eficacia del enfoque. Se requiere de mayor investigación para optimizar el manejo médico.

Objective: to study the results in patients undergoing infertility treatment with a focus on restorative medicine (NaProTechnology) at a department of obstetrics and gynecology. Methodology: retrospective cohort study conducted by the gynecology and obstetrics department at Universidad de los Andes (Santiago, Chile) in infertility patients from a suburban area of Santiago de Chile, who received treatment between 2006 and 2014. All couples received instructions on how to recognize their fertility period according to a local teaching model based on the Creighton Model FertilityCare System. They also received medical treatment to induce ovulation and/or widen their fertile period, or surgical treatment. The main outcome was the number of pregnancies. Results: 131 patients received instructions. The mean age was 33.6 years. Seventyeight patients (59.5%) consulted due to primary infertility; 53 (40.5%) due to secondary infertility. The duration of group infertility was 4.1 years. The mean use of the method was 12.6 months (median, 9 months). The infertility causes identified included anovulation (50.4%), tubo-peritoneal factors (18.3%), endometriosis (14.5%), uterine factors (9.2%), cervical factors (8.4%) and masculine factors (19.1%). There were 33 pregnancies (25.2 global). The crude proportion of pregnancies at 24 months was 22.9% and the proportion adjusted by the life table at 24 months was 40 per 100 couples. Conclusions: the focus on restorative medicine is effective to achieve pregnancy but it requires a long-term longitudinal treatment. Early discontinuation of fertility charting affects the efficacy of this focus. More research is warranted to optimize medical treatment.

Objetivo: estudar os resultados das pacientes com infertilidade tratadas com um enfoque de medicina restaurativa (naprotecnologia) em um serviço de ginecologia y obstetrícia. Metodologia: estudo de coorte retrospectivo realizado pelo departamento de obstetrícia e ginecologia da Universidad de los Andes (Santiago, Chile) em pacientes com infertilidade de uma área suburbana de Santiago de Chile, que receberam tratamento entre 2006 e 2014. Todas os casais receberam instrução para reconhecer seu período de fertilidade segundo um modelo local de ensinamento, baseado no modelo Creigthon (Creigthon Model FertilityCare System). Receberam, ademais, tratamento médico para indução de ovulação, melhoramento do período fértil ou cirurgia reparadora. A medição primária foi o número de gravidez. Resultados: 131 pacientes receberam a instrução. A média de idade foi de 33.6 anos. 78 pacientes (59.5%) consultaram por infertilidade primária; 53 (40.5%), infertilidade secundária. O tempo de infertilidade do grupo foi de 4.1 anos. A média de uso do método foi de 12.6 meses (mediana, 9 meses). As causas de infertilidade identificadas foram anovulação (50.4%), tubo-peritoneal (18.3%), endometriose (14.5%), uterino (9.2%), cervical (8.4%) e masculino (19.1%). Houve 33 gravidezes (25.2 global). A proporção crua de gravidezes aos 24 meses foi de 22.9% e a ajustada por tabela de vida aos 24 meses foi de 40 por 100 casais. Conclusões: o enfoque de medicina restaurativa é efetivo para conseguir gravidezes mas requere de um manejo longitudinal a longo prazo. O abandono precoce do uso do registro de fertilidade afeta a eficácia do enfoque. Se requere de maior investigação para otimizar o manejo médico.

Broadband single-polarization guidance in hybrid photonic crystal fibers.

We present hybrid photonic crystal fibers that provide broadband single-polarization guidance based on two different propagation mechanisms, namely, total internal reflection and the photonic bandgap effect. Experimental results demonstrate polarization dependent loss as high as 26.7 dB and the bandwidth of single-polarization behavior over 225 nm.

Efficient calculation of higher-order optical waveguide dispersion.

An efficient numerical strategy to compute the higher-order dispersion parameters of optical waveguides is presented. For the first time to our knowledge, a systematic study of the errors involved in the higher-order dispersions' numerical calculation process is made, showing that the present strategy can accurately model those parameters. Such strategy combines a full-vectorial finite element modal solver and a proper finite difference differentiation algorithm. Its performance has been carefully assessed through the analysis of several key geometries. In addition, the optimization of those higher-order dispersion parameters can also be carried out by coupling to the present scheme a genetic algorithm, as shown here through the design of a photonic crystal fiber suitable for parametric amplification applications.

Clinical and biochemical improvement of very long-chain acyl-CoA dehydrogenase deficiency in pregnancy.

Very long-chain acyl-CoA dehydrogenase (VLCAD) deficiency is an enzymatic defect of the fatty acid (FA) beta oxidation pathway. In catabolic states, such as labor and early postpartum period, patients are potentially prone to metabolic decompensation and subsequent rhabdomyolysis with increased risk for myoglobinuria and renal insufficiency. We report a 21-year-old primigravida with a previously characterized VLCAD deficiency, who experienced frequent and unprovoked episodes of rhabdomyolysis before pregnancy. As there was no published experience to guide her management, a detailed multidisciplinary care plan was established to minimize the potential morbidity. Although there is little known about the antenatal course of gravidae affected by VLCAD, we predicted that placental and fetal beta-oxidation in an unaffected pregnancy may temporize or even improve maternal FA beta-oxidation. Consistent with our prediction, we observed a significant clinical and biochemical improvement throughout her pregnancy, and she delivered vaginally with an uncomplicated postpartum course. We conclude that although VLCAD deficiency can present a therapeutic challenge during pregnancy, the beneficial placento-maternal metabolic interactions and the implementation of a proper peripartum management reassure a successful antenatal and perinatal outcome.

Ion-exchanged Er3+/Yb3+ co-doped waveguide amplifiers longitudinally pumped by broad area lasers.

A multimode pumping scheme for Er(3+)/Yb(3+) co-doped waveguide amplifiers based on broad area lasers at around 980 nm is presented. The proposed amplifier is fabricated by ion-exchange (IE) technique on silicate and phosphate glasses. The highly efficient energy transfer from Yb(3+) to Er(3+) ions, combined with the use of low cost and high power broad area laser, allows the realization of high performance and cost-effective integrated amplifiers. The structure has been designed and numerically studied using a 3D finite element modelling tool, and over 3 dB/cm small signal gain has been predicted for an optimized amplifier. Preliminary characterization of an amplifier structure provides a first experimental evidence of the novel multimode longitudinal pumping.

Inversion of gradient forces for high refractive index particles in optical trapping.

The unexpected fact that a spherical dielectric particle with refractive index higher than the surrounding medium will not always be attracted towards high intensity regions of the trapping beam is fully demonstrated here using a simple ray optics approach. This unusual situation may happen due to the inversion of gradient forces, as shown here. Therefore, conventional schemes, such the one based on the use of two counter-propagating beams to cancel the scattering forces, will fail to trap the particle. However, effective trapping still can be obtained by adopting suitable incident laser beams.

Trapping double negative particles in the ray optics regime using optical tweezers with focused beams.

The capabilities of optical tweezers to trap DNG (double negative) spherical particles, with both negative permittivity and permeability, are explored in detail by analyzing some interesting theoretical features not seeing in conventional DPS (double positive) particles possessing positive refractive index. The ray optics regime is adopted and, although this regime is quite simple and limited, its validity is already known and tested for DPS particles such as biological cells and molecules trapped by highly focused beams. Simulation results confirm that even for ray optics, DNG particles present unusual and interesting trapping characteristics.

Nonlinear interaction between two different photonic bandgaps of a hybrid photonic crystal fiber.

Nonlinear interaction between spectral components in two different photonic bandgaps is experimentally demonstrated by launching femtosecond pulses near a zero-dispersion wavelength of a hybrid photonic crystal fiber, which guides by a combination of total internal reflection and bandgap effects. It is demonstrated that the initial pulse becomes spectrally broadened, and narrowband resonant radiation is generated in a different bandgap from the one responsible for guiding at the pump wavelength. The spectral intensity of the resonant radiation peaks at 2.7 dB below that of the broadened pulse in the pump-guiding bandgap.

Highly efficient generation of broadband cascaded four-wave mixing products.

We propose a novel way to efficiently generate broadband cascaded Four-Wave Mixing (FWM) products. It consists of launching two strong pump waves near the zero-dispersion wavelength of a very short (of order a few meters) optical fiber. Simulations based on Split Step Fourier Method (SSFM) and experimental data demonstrate the efficiency of our new approach. Multiple FWM products have been investigated by using conventional fibers and ultra-flattened dispersion photonic crystal fibers (UFD-PCFs). Measured results present bandwidths of 300 nm with up to 118 FWM products. We have also demonstrated a flat bandwidth of 110 nm covering the C and L bands, with a small variation of only 1.2 dB between the powers of FWM products, has been achieved using highly nonlinear fibers (HNLFs). The use of UFD-PCFs has been shown interesting for improving the multiple FWM efficiency and reducing the separation between the pump wavelengths.

Study of an efficient longitudinal multimode pumping scheme for Si-nc sensitized EDWAs.

We present an efficient multimode longitudinal pumping scheme which overcomes the main limitations of single-mode longitudinal pumping as well as top pumping in Si-nanoclusters sensitized Erbium-doped waveguide amplifiers. The proposed configuration is based on evanescent pump light coupling from a multimode waveguide to a Si-nanoclusters sensitized Er(3+)-doped active core. Theoretical predictions, based on propagation and population-rate equations for the coupled Er(3+)/Sinanoclusters system, point out that the proposed pumping scheme can provide high pump intensity within the active core, also ensuring good uniformity of the population inversion along the waveguide amplifier. Although longitudinal multimode pumping by high power LEDs in the visible can potentially lead to low cost integrated amplifiers, further material optimization is required. In particular, we show that when dealing with high pump intensities, confined carrier absorption seriously affects the amplifier performance, and an optimization of both Si-nc and Er(3+) concentrations is necessary.

Band gap of hexagonal 2D photonic crystals with elliptical holes recorded by interference lithography.

Two-dimensional hexagonal photonic crystals can be recorded using the simple superimposition of two interference patterns rotated by 60 masculine. Such process generates high contrast masks, however, it generates elliptical cross section structures instead of cylinders. We study the PBG properties of the experimentally feasible geometries, using this technique and we demonstrate that the effect of this asymmetric shape is a reduction in the PBG map area, for TE polarization, in comparison with cylindrical structures. On the other hand, it appears a PBG for TM polarization.