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Objectives: To describe the appearance and size of the ganglionic eminence (GE) in normal fetuses on midtrimester three‐dimensional (3D) neurosonography and to report on the association between GE alterations (cavitation or enlargement) and malformation of cortical development (MCD). Methods: This was a prospective multicenter cohort study of normal fetuses and a retrospective analysis of pathological cases with MCD. From January 2022 to June 2022, patients attending our tertiary centers for an expert fetal brain scan were recruited for the purpose of the study. A 3D volume of the fetal head, starting from the sagittal plane, was acquired in apparently normal fetuses using a transabdominal or transvaginal approach. Stored volume datasets were then evaluated independently by two expert operators. Two measurements (longitudinal diameter and transverse diameter) of the GE in the coronal view were obtained twice by each operator. Intra‐ and interobserver measurement variation was calculated. Reference ranges for GE measurements were calculated in the normal population. A previously stored volume dataset of 60 cases with MCD was also analyzed independently by the two operators using the same method in order to assess if GE abnormalities (cavitation or enlargement) were present. Postnatal follow‐up was obtained in all cases. Results: In the study period, 160 normal fetuses between 19 and 22 weeks of gestation were included in the study. The GE was visible in the coronal plane on 3D neurosonography in 144 (90%) cases and was not clearly visible in the remaining 16 (10%) cases. The intra‐ and interobserver agreement was almost perfect for the longitudinal diameter, with an intraclass correlation coefficient (ICC) of 0.90 (95% CI, 0.83–0.93) and 0.90 (95% CI, 0.86–0.92), respectively, and substantial for the transverse diameter, with an ICC of 0.80 (95% CI, 0.70–0.87) and 0.64 (95% CI, 0.53–0.72), respectively. A retrospective analysis of 50 cases with MCD in the second trimester showed that GE enlargement was present in 12 cases and GE cavitation was present in four cases. Conclusions: Systematic assessment of the GE in fetuses at 19–22 weeks of gestation is feasible on 3D neurosonography, with good reproducibility in normal cases. Cavitation or enlargement of the GE can be demonstrated in fetuses with MCD. © 2023 The Authors. Ultrasound in Obstetrics & Gynecology published by John Wiley & Sons Ltd on behalf of International Society of Ultrasound in Obstetrics and Gynecology. [ABSTRACT FROM AUTHOR]

Studies of angiosperms have associated the mechanical design of petioles with leaf form and the occurrence of simple and compound leaves. Petiole anatomy can respond differently, according to different leaf forms, to maintain plant architecture. The present study evaluated whether this premise applies to fern leaf architecture. Leaves of five ferns (Blechnum binervatum (Poir.) C.V. Morton & Lellinger, Ctenitis falciculata (Raddi) Ching, Megalastrum connexum (Kaulf.) A.R. Smith & R.C. Moran, Microgramma squamulosa (Kaulf.) de la Sota, and Serpocaulon catharinae (Langsd. & Fisch.) A.R. Sm.) from a remnant of an Araucaria Forest in southern Brazil were collected and their morphological and anatomical traits were analyzed. Results indicate that the biomechanical patterns of these terrestrial and epiphytic ferns are similar to those reported for angiosperms, except for the presence of subepidermal sclerenchyma in fern petioles. Independently of leaf form, the rigid structure of fern petioles appears to be an important adaptation to biomechanically support leaf position for maximum light interception in forest understories. Key words: Atlantic Forest, fern ecology, leaf morphology, petiole anatomy, sclerenchyma. Resume: Les etudes sur les angiospermes ont associe la structure mecanique des petioles avec la forme de la feuille ainsi que la presence de feuilles simples et composees. L'anatomie du petiole peut reagir differemment selon les differentes formes de feuille pour maintenir l'architecture de la plante. Les auteurs ont verifie si cette premices s'applique a l'architecture des feuilles de fougere. Les observations ont porte sur les feuilles de cinq especes de fougeres (Blechnum binervatum (Poir.) C.V. Morton & Lellinger, Ctenitis falciculata (Raddi) Ching, Megalastrum connexum (Kaulf.) A.R. Smith & R.C. Moran, Microgramma squamulosa (Kaulf.) de la Sota et Serpocaulon catharinae (Langsd. & Fisch.) A.R. Sm.) provenant d'une foret vestigiale d'Araucaria du sud du Bresil; les auteurs en ont recolte les feuilles et analyse leurs caracteres morphologiques et anatomiques. Les resultats indiquent que les patrons biomecaniques de ces fougeres epiphytes terrestres se confondent avec ceux rapportes pour des angiospermes, sauf pour la presence de sclerenchyme subepidermique dans les petioles de fougere. Independamment de la forme foliaire, la structure rigide des petioles de fougere semble constituer une importante adaptation comme support biomecanique de la position de la feuille afin d'intercepter un maximum de lumiere dans les sous-bois des forets. [Traduit par la Redaction] Mots-cles: foret atlantique, ecologie des fougeres, morphologie foliaire, anatomie du petiole, sclerenchyme., Introduction Limitations to the establishment of species are intimately related to their patterns of biomass allocation in different organs or structures, including the whole plant or its leaves. Such patterns [...]

This article, published in the journal Ultrasound in Obstetrics & Gynecology, describes a study conducted at two referral Fetal Medicine units to examine the sonographic features of the caudo-thalamic (CT) groove in the third trimester of pregnancy. The study included a cohort of normal fetuses who underwent 3D ultrasound of the fetal brain, and the results showed that the CT groove was consistently visible in the majority of cases. Additionally, the researchers found five cases with abnormal appearance of the groove, which suggests that abnormal findings at this level can be detected during antenatal brain ultrasound. The study provides valuable insights into fetal neurosonography and its potential for detecting abnormalities. [Extracted from the article]

Charge transport and Random Telegraph Noise (RTN) are measured successfully at the nanoscale on a thin polycrystalline HfO2 film using room temperature Scanning Tunneling Microscopy (STM). STM is used to scan the surface of the sample with the aim of identifying grains and grain boundaries, which show different charge transport characteristics. The defects responsible for charge transport in grains and grain boundaries are identified as positively charged oxygen vacancies by matching the localized I-V curves measured at the nanoscale with the predictions of physics-based multi-scale simulations. The estimated defect densities at grains and grain boundaries agree with earlier reports in the literature. Furthermore, the current-time traces acquired by STM at fixed bias voltages on grains show characteristic RTN fluctuations. The high spatial resolution of the STM-based RTN measurement allows us to detect fluctuations related to individual defects that typically cannot be resolved by the conventional device-level probe station measurement. The same physical framework employed to reproduce the I-V conduction characteristics at the grains also successfully simulates the RTN detected at the nanoscale. We confirm that charge trapping at defects not directly involved in charge transport can induce significant current fluctuations through Coulombic interactions with other defects in the proximity that support charge transport. [ABSTRACT FROM AUTHOR]

Recent developments of ultra-low heat capacity nanostructured materials revived the interest in the thermo-acoustic (TA) loudspeaker technology, which shows important advantages compared to the classical dynamic loudspeakers as they feature a lower cost and weight, flexibility, conformability to the surface of various shapes, and transparency. The development of the TA loudspeaker technology requires accurate physical models connecting the material properties to the thermal and acoustic speaker’s performance. We present here a combined theoretical and experimental analysis of TA loudspeakers, where the electro-thermal and the thermo-acoustic transductions are handled separately, thus allowing an in-depth description of both the pressure and temperature dynamics. The electro-thermal transduction is analyzed by accounting for all the heat flow processes taking place between the TA loudspeaker and the surrounding environment, with focus on their frequency dependence. The thermo-acoustic conversion is studied by solving the coupled thermo-acoustic equations, derived from the Navier-Stokes equations, and by exploiting the Huygens-Fresnel principle to decompose the TA loudspeaker surface into a dense set of TA point sources. A general formulation of the 3D pressure field is derived summing up the TA point source contributions via a Rayleigh integral. The model is validated against temperature and sound pressure level measured on the TA loudspeaker sample made of a Silver Nanowire random network deposited on a polyimide substrate. A good agreement is found between measurements and simulations, demonstrating that the model is capable of connecting material properties to the thermo-acoustic performance of the device, thus providing a valuable tool for the design and optimization of TA loudspeakers. [ABSTRACT FROM AUTHOR]

Despite extensive experimental and theoretical studies, the atomistic mechanisms responsible for dielectric breakdown (BD) in amorphous (a)-SiO2 are still poorly understood. A number of qualitative physical models and mathematical formulations have been proposed over the years to explain experimentally observable statistical trends. However, these models do not provide clear insight into the physical origins of the BD process. Here, we investigate the physical mechanisms responsible for dielectric breakdown in a-SiO2 using a multi-scale approach where the energetic parameters derived from a microscopic mechanism are used to predict the macroscopic degradation parameters of BD, i.e., time-dependent dielectric breakdown (TDDB) statistics, and its voltage dependence. Using this modeling framework, we demonstrate that trapping of two electrons at intrinsic structural precursors in a-SiO2 is responsible for a significant reduction of the activation energy for Si-O bond breaking. This results in a lower barrier for the formation of O vacancies and allows us to explain quantitatively the TDDB data reported in the literature for relatively thin (3-9 nm) a-SiO2 oxide films. [ABSTRACT FROM AUTHOR]

Single ions impacting on Si[O.sub.2] layers generate tracks of defects which may result in a Radiation Induced Leakage Current (RILC). This current is usually studied as the cumulative effect of ion-induced defects in capacitors with ultra-thin oxides. We are demonstrating and modeling this phenomenon in 10 nm oxides by using Floating Gate memories. The impact of a single, high-LET ion can result in severe retention problems, due to several electrically active defects, which cooperate to slowly discharge the FG. We are also proposing innovative simulation tools to reproduce this phenomenon. Results from simulations fully explain our results, and also agree with existing data on thinner (4 nm) oxides. Index Terms--Floating gate memories, radiation induced leakage current, single event effects.