OC225: Diagnosis of chorionicity at 10-19 weeks by 2D and 3D-4D scan

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P040: Nasal bone visualization: A comparison between 3D and 2D ultrasound in the first-early second trimester

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Ulipristal acetate before in vitro fertilization: Efficacy in infertile women with submucous fibroids

Background: The presence of submucous fibroids strongly impacts on IVF results, therefore, these patients should be considered for surgical or medical treatment. The aim of this study was to assess the role of Ulipristal acetate (UPA), a selective progesterone receptor modulator, in restoring uterine cavity deformation due to submucous fibroids, in infertile patients attempting an IVF treatment. The secondary study outcome was to evaluate the impact of preconception UPA treatment on rate of biochemical pregnancy, ongoing pregnancy, and live birth compared to a control group without fibroids. Methods: Infertile patients with submucosal fibroid (Type 1 and Type 2 according to FIGO classification) were enrolled in the study as fibroids group and received 1 to 3 treatment cycles of UPA, according to their response, as reflected by fibroid volume reduction and restoration of normal uterine cavity. Patients in control group were randomly selected from a general IVF cohort by a ratio of 2:1 with fibroids group, matched by age, BMI, type and cause of infertility and antral follicle count. The impact of UPA on fibroids volume reduction was evaluated. IVF outcome was compared between groups. Results: Twenty-six patients underwent UPA treatment revealed a mean volume reduction of their fibroids of 41%. A total of 15 (57.6%) biochemical pregnancy were obtained, resulting in 13 (50%) ongoing pregnancy and 9 (34.6%) healthy babies were already delivered. Similar results were obtained in control group. Conclusion: Restoration of normal uterine cavity by UPA treatment prior to IVF treatment avoids surgery and establishes a pregnancy rate comparable to a control group without fibroids

Second harmonic generation on self-assembled GaAs/Au nanowires with thickness gradient

Here we investigated the SH generation at the wavelength of 400 nm (pump laser at 800 nm, 120 fs pulses) of a "metasurface" composed by an alternation of GaAs nano-grooves and Au nanowires capping portions of flat GaAs. The nano-grooves depth and the Au nanowires thickness gradually vary across the sample. The samples are obtained by ion bombardment at glancing angle on a 150 nm Au mask evaporated on a GaAs plane wafer. The irradiation process erodes anisotropically the surface, creating Au nanowires and, at high ion dose, grooves in the underlying GaAs substrate (pattern transfer). The SHG measurements are performed for different pump linear polarization angle at different positions on the "metasurface" in order to explore the regions with optimal conditions for SHG efficiency. The pump polarization angle is scanned by rotating a half-wave retarder plate. While the output SH signal in reflection is analyzed by setting the polarizer in s or p configuration in front of the detector. The best polarization condition for SHG is obtained in the configuration where the pump and second harmonic fields are both p polarized, and the experiments show a SH polarization dependence of the same symmetry of bulk GaAs. Thus, the presence of gold contributes only as field localization effect, but do not contributes directly as SH generator

Resonant Absorption in GaAs-Based Nanowires by Means of Photo-Acoustic Spectroscopy

Semiconductor nanowires made of high refractive index materials can couple the incoming light to specific waveguide modes that offer resonant absorption enhancement under the bandgap wavelength, essential for light harvesting, lasing and detection applications. Moreover, the non-trivial ellipticity of such modes can offer near field interactions with chiral molecules, governed by near chiral field. These modes are therefore very important to detect. Here, we present the photo-acoustic spectroscopy as a low-cost, reliable, sensitive and scattering-free tool to measure the spectral position and absorption efficiency of these modes. The investigated samples are hexagonal nanowires with GaAs core; the fabrication by means of lithography-free molecular beam epitaxy provides controllable and uniform dimensions that allow for the excitation of the fundamental resonant mode around 800 nm. We show that the modulation frequency increase leads to the discrimination of the resonant mode absorption from the overall absorption of the substrate. As the experimental data are in great agreement with numerical simulations, the design can be optimized and followed by photo-acoustic characterization for a specific application

Quantitative evaluation of emission properties and thermal hysteresis in the mid-infrared for a single thin film of vanadium dioxide on a silicon substrate

We present a comparative study of the emission properties of a vanadium dioxide thin film (approximately 200 nm) deposited on a silicon wafer in different sub-spectral-ranges of the mid-infrared, with particular attention to the windows of transparency of the atmosphere to the infrared radiation (i.e., 3–5 μm, 8–12 μm). The infrared emission properties of the structure are closely related to the well-known phase transition of the first order, from semiconductor to metal, of the vanadium dioxide around the temperature of 68 °C. The characterization of the emissivity in the sub-regions of the mid-infrared was carried out both in the front configuration, that is on the VO2 film side, and in the rear configuration on the silicon wafer side, and showed a strong difference in the hysteresis thermal bandwidth, in particular between the short wave region and the long wave region. The bandwidth is equal to 12 °C for the front and 15 °C for the rear. The emissivity behaviors as a function of temperature during the semiconductor-metal transition in the mid-infrared subregions were analyzed and explained using the theories of the effective medium of Maxwell Garnett and Bruggeman, highlighting the greater functionality of one theory with respect to the other depending on the spectral detection band

Control of Au nanoantenna emission enhancement of magnetic dipolar emitters by means of VO2 phase change layers

Active, ultra-fast external control of the emission properties at the nanoscale is of great interest for chip-scale, tunable and efficient nanophotonics. Here we investigated the emission control of dipolar emitters coupled to a nanostructure made of an Au nanoantenna, and a thin vanadium dioxide (VO2) layer that changes from semiconductor to metallic state. If the emitters are sandwiched between the nanoantenna and the VO2 layer, the enhancement and/or suppression of the nanostructure’s magnetic dipole resonance enabled by the phase change behavior of the VO2 layer can provide a high contrast ratio of the emission efficiency. We show that a single nanoantenna can provide high magnetic field in the emission layer when VO2 is metallic, leading to high emission of the magnetic dipoles; this emission is then lowered when VO2 switches back to semiconductor. We finally optimized the contrast ratio by considering different orientation, distribution and nature of the dipoles, as well as the influence of a periodic Au nanoantenna pattern. As an example of a possible application, the design is optimized for the active control of an Er3+ doped SiO2 emission layer. The combination of the emission efficiency increase due to the plasmonic nanoantenna resonances and the ultra-fast contrast control due to the phase-changing medium can have important applications in tunable efficient light sources and their nanoscale integration

Enhanced second harmonic generation from resonant GaAs gratings

We study second harmonic generation in nonlinear, GaAs gratings. We find large enhancement of conversion efficiency when the pump field excites the guided mode resonances of the grating. Under these circumstances the spectrum near the pump wavelength displays sharp resonances characterized by dramatic enhancements of local fields and favorable conditions for second harmonic generation, even in regimes of strong linear absorption at the harmonic wavelength. In particular, in a GaAs grating pumped at 1064nm, we predict second harmonic conversion efficiencies approximately five orders of magnitude larger than conversion rates achievable in either bulk or etalon structures of the same material.Comment: 8 page

Gap solitons in a nonlinear quadratic negative index cavity

By integrating the full Maxwell's equations we predict the existence of gap solitons in a quadratic, Fabry-Perot negative index cavity. An intense, fundamental pump pulse shifts the band structure that forms when magnetic and electric plasma frequencies are different so that a weak, second harmonic pulse initially tuned inside the gap is almost entirely transmitted. The process is due cascading, which occurs far from phase matching conditions, and causes pulse compression. A nonlinear polarization spawns a dark soliton, while a nonlinear magnetization produces a bright soliton

A Reappraisal of Lymphadenectomy in Common Gynecological Cancers

Objectives: Lymph node dissection (LND) in gynecological malignancies has always been a cornerstone in the diagnosis of metastasis, it is also considered an important prognostic factor, and a reliable guide to management strategies. However, its incidence of complications, namely lymphedema, vascular injuries and other lesions, has led to a reconsideration of its efficacy and a comparison of the role of systematic vs. sentinel lymph node (SLN) dissection. Mechanism: Review of the literature using keywords such as “lymph nodes”, “sentinel lymph nodes”, “morbidity and mortality”, “gynecological cancers”, “endometrial cancer”, “ovarian cancer”, and “cervical cancer”. Findings in Brief: In the case of endometrial cancer, several studies have investigated the efficacy of SLN compared with systematic LND. Most of the results demonstrated the efficacy of SLN dissection in endometrial cancer, with the added benefit of lower morbidity. In patients with ovarian cancer, the mainstay of treatment is debulking with optimal cytoreductive surgery. Recent studies have compared systematic lymphadenectomy to non-lymphadenectomy, with an additional advantage in the cases of lymphadenectomy. However, since its publication, the lymphadenectomy in ovarian cancers (LIONS) trial, has revolutionized the standard of care for patients with advanced ovarian cancer and has called into question the increased morbidity and mortality in systematic lymphadenectomy. In cervical cancers, lymph node status is considered to be the most important prognostic factor. In this case, limiting lymphadenectomy to the borders of the inferior mesenteric artery seems promising, and studies are currently being carried out to investigate the feasibility of SLN dissection instead of systematic lymph node dissection. Conclusions: SLN dissection is associated with lower morbidity and mortality, and has been shown to be superior to systematic lymphadenectomy in several studies. However, more research and specific guidelines are needed to better select either one or the other method in the management of gynecological cancers. Copyright: © 2023 The Author(s)