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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

Maturation of pig oocytes in vitro in a medium with pyruvate.

The aim of in vitro maturation oocyte systems is to produce oocytes of comparable quality to those derived in vivo. The present study was designed to examine the surface morphological changes of the cumulus-oocyte complex (COC) and nuclear maturation in a culture system containing pyruvate. Ovaries were obtained from a slaughterhouse and transported to the laboratory within 2 h at 35-39 degrees C,and rinsed three times in 0.9% NaCl. The COCs were harvested from the ovaries and in vitro maturation was evaluated in San Marcos (SM) medium, a chemically defined culture system containing 22.3 mM sodium pyruvate. Oocytes were cultured in SM, SM + porcine follicular fluid (pFF) and in SM + pFF + gonadotropins (eCG and hCG) for 20-22 h and then without hormonal supplements for an additional 20-22 h. After culture, the degree of cumulus expansion and frequency of nuclear maturation were determined. Oocytes matured in SM (40.9%) and SM + pFF (42.9%) showed moderate cumulus expansion, whereas oocytes matured in SM + pFF + gonadotropins (54.6%) showed high cumulus expansion. The maturation rate of cultured oocytes, measured in function of the presence of the polar corpuscle, did not differ significantly between SM (40.9 +/- 3.6%) and SM + pFF (42.9 +/- 3.7%). These results indicate that pig oocytes can be successfully matured in a chemically defined medium and suggest a possible bifunctional role of pyruvate as an energy substrate and as an antioxidant protecting oocytes against the stress of the in vitro environment.

Effects of thalidomide on HIV-associated wasting syndrome: a randomized, double-blind, placebo-controlled clinical trial.

OBJECTIVE: To evaluate the efficacy of thalidomide in treating wasting syndrome in patients with advanced HIV disease, and to assess the effects of thalidomide on circulating CD4+ T cells, and on HIV viral burden in peripheral blood mononuclear cells (PBMC). DESIGN: Randomized, double-blind placebo-controlled clinical trial. SETTING: Public tertiary care hospital in Mexico City. PATIENTS: Twenty-eight adults with advanced HIV disease being treated with antiretroviral therapy, and who had received antiretrovirals for at least 6 months, who did not have an active opportunistic infection, and who had 10% weight loss in the previous 6 months. INTERVENTIONS: Patients received thalidomide (100 mg by mouth, four times daily) or a matching placebo for the duration of the study (12 weeks). MAIN OUTCOME MEASURES: The main clinical endpoint for efficacy of thalidomide was weight gain or no progression of wasting. Secondary endpoints were Karnofsky performance status, CD4+ cell counts, and HIV viral burden in PBMC. RESULTS: Both groups were comparable in their baseline status. Therapeutic failure occurred in 10 out of 14 patients from the placebo group and in three out of 14 from the thalidomide group (P = 0.021). Weight gain occurred in one patient on placebo and in eight given thalidomide. The Karnofsky index was significantly higher by the end of the study in the thalidomide group (P = 0.003). Mild and transient somnolence and erythematous macular skin lesions were significantly more common in the thalidomide group. CD4+ T cell counts and HIV viral burden in PBMC did not change in either group. CONCLUSIONS: Results suggest that thalidomide not only impeded but also reverted the wasting syndrome, preserving the Karnofsky index in patients with advanced HIV disease. Thalidomide, at the dosage used in this study, had no effect on peripheral CD4+ T cells nor on HIV viral burden in PBMC.

Novel numerical method for the analysis of 2D photonic crystals: the cell method.

The Cell Method, a new efficient numerical method suitable for working with periodic structures having anisotropic inhomogeneous media with curved shapes, is proposed in order to calculate the band gap of 2D photonic crystals for in-plane propagation of TM and TE waves. Moreover some numerical comparisons with other numerical methods will be provided.

Early formation of the nodule in Guatemalan onchocerciasis.

Thirty-eight nodules containing adults of Onchocerca volvulus were removed from 36 patients who had no detectable microfilariae in skin snips. Worms were digested from nodules in collagenase solution, maintained alive in vitro, and the number, sex, and state of fecundity were recorded. A total of 48 female and 8 male worms were recovered; 39 females were in the nodules without the presence of a male. Eleven females (22.9%) had microfilariae in utero or produced microfilariae in vitro; seven of these were found together with males in the nodules while four were not. No nodules were found around male worms unless a female was also present. These observations indicate that the nodule forms only around female worms and that mating probably occurs before or early during nodule formation. Furthermore, the production of microfilariae by the the female is not essential for nodule formation since many nodules contained non-fecund, living females.

Diagnosis of Onchocerca volvulus infection in Guatemalan children.

Nodule examination, the Mazzotti test (a provocative challenge with diethylcarbamazine), and the enzyme-linked immunosorbent assay (ELISA) were compared for diagnostic efficacy in children who were born in an area endemic for onchocerciasis in Guatemala and were skin-biopsy negative for microfilaria of Onchocerca volvulus. Four groups of children under 16 years of age were formed based upon the possible combinations of nodule positivity or negativity and ELISA positivity or negativity. Only those children with a positive (greater than or equal to 1:160) ELISA titer had a positive Mazzotti test (9 of 20 tested), regardless of the presence or absence of nodules. These results suggest that the current ELISA serology is highly sensitive for low density infections, and should be considered in surveys for the incidence of new Onchocerca infections.

Novel combination of c-myc, N-myc and N-ras oncogene alteration in brain tumors.

We have examined forty human brain tumors (neoplasias presenting an important incidence in Mexico), for cellular myc (c-myc), N-myc and N-ras proto-oncogene alterations. An elevated amplification and/or rearrangement of the oncogenes was detected in most samples (60% presenting alteration for c-myc, 54% for N-myc, 6% for N-ras and 60% for ras-related genes). The tumors were of different histological types and for some of them we detected either amplification and/or rearrangement of the oncogenes. We describe, for the first time, the alterations of two related genes (c-myc and N-myc) in the same tumor samples; in 64% of the analyzed samples, oncogene alterations were accompanied by enhanced expression of N-myc and ras-related genes. These results suggest an important role for c-myc, N-myc and N-ras oncogenes, in the development and progression of brain tumors.

Sowda-type onchocerciasis in Guatemala.

The usual pattern of onchocercal dermatitis in Africans and Guatemalans is a generalized and symmetrical dermatitis located on legs, arms and trunk. These patients appear to be anergic, with depressed immune responses and numerous microfilariae in the skin. In contrast, "sowda" is an unusual type of onchocercal dermatitis found in Yemenites and in a minority of African patients. Here the dermatitis is localized and asymmetrical - typically confined to one limb or one region of the body. Patients with sowda appear to be hypergic, with active humoral and cellular immune responses; microfilariae are rare or absent. This study describes two Guatemalan patients with sowda-type dermatitis. The diagnosis in these two patients is based on the asymmetrical papular pruritic dermatitis, rare or absent microfilariae, a positive Mazzotti reaction, and histopathologic changes characteristic of the sowda-type onchocercal dermatitis.