Search

This work presents the polarization‐dependent behavior of the anapole state in stacked amorphous silicon (a‐Si) nanodisks with elliptical geometries. Using SiO2 as a spacer layer between the a‐Si disks, the high index contrast between these materials can be used to significantly reduce the fabrication complexity of the system compared to traditional methods that require additional etching of the spacers. A novel way of continuous tuning of the electric dipole anapole excitation within elliptical stacked a‐Si nanoresonators is demonstrated. By rotating the incident electric field's polarization angle, the anapole state can be selectively excited at two distinct wavelength positions separated by 80 nm. Experimental results show characteristic dips in the reflectance of the fabricated elliptical a‐Si stacks with wavelength positions between 1135 and 1217 nm depending on the polarization angle of the incident field which is corroborated by FDTD simulations. Through simulating the internal electric field in the resonators and using multipole decomposition, it is shown that the reflectance dips are due to anapole excitation in the individual disks. The capability to excite anapoles at two distinct wavelengths in the same structure has promising implications for the development of tunable sensors, frequency converters, and quantum memory applications.

Purpose: Sex classification is a major benchmark of previous work in learning on the structural connectome, a naturally occurring brain graph that has proven useful for studying cognitive function and impairment. While graph neural networks (GNNs), specifically graph convolutional networks (GCNs), have gained popularity lately for their effectiveness in learning on graph data, achieving strong performance in adult sex classification tasks, their application to pediatric populations remains unexplored. We seek to characterize the capacity for GNN models to learn connectomic patterns on pediatric data through an exploration of training techniques and architectural design choices. Methods: Two datasets comprising an adult BRIGHT dataset (N = 147 Hodgkin's lymphoma survivors and N = 162 age similar controls) and a pediatric Human Connectome Project in Development (HCP-D) dataset (N = 135 healthy subjects) were utilized. Two GNN models (GCN simple and GCN residual), a deep neural network (multi-layer perceptron), and two standard machine learning models (random forest and support vector machine) were trained. Architecture exploration experiments were conducted to evaluate the impact of network depth, pooling techniques, and skip connections on the ability of GNN models to capture connectomic patterns. Models were assessed across a range of metrics including accuracy, AUC score, and adversarial robustness. Results: GNNs outperformed other models across both populations. Notably, adult GNN models achieved 85.1% accuracy in sex classification on unseen adult participants, consistent with prior studies. The extension of the adult models to the pediatric dataset and training on the smaller pediatric dataset were sub-optimal in their performance. Using adult data to augment pediatric models, the best GNN achieved comparable accuracy across unseen pediatric (83.0%) and adult (81.3%) participants. Adversarial sensitivity experiments showed that the simple GCN remained the most robust to perturbations, followed by the multi-layer perceptron and the residual GCN. Conclusions: These findings underscore the potential of GNNs in advancing our understanding of sex-specific neurological development and disorders and highlight the importance of data augmentation in overcoming challenges associated with small pediatric datasets. Further, they highlight relevant tradeoffs in the design landscape of connectomic GNNs. For example, while the simpler GNN model tested exhibits marginally worse accuracy and AUC scores in comparison to the more complex residual GNN, it demonstrates a higher degree of adversarial robustness. [ABSTRACT FROM AUTHOR]

Background and Aims: No studies have compared the effects of ketamine and dexmedetomidine on bowel recovery. We evaluated the effects of intraoperative low-dose ketamine or dexmedetomidine infusion on postoperative bowel recovery in patients undergoing gastrointestinal (GI) malignancy surgeries. Material and Methods: This placebo-controlled, randomized study was carried out in 84 American Society of Anesthesiologists II patients, aged 18–70 years, of either gender, undergoing elective open GI malignancy surgeries. Patients received intraoperative infusion of ketamine @ 0.1 mg kg-1 h-1 (KET), dexmedetomidine @ 0.25 μg kg-1 h-1 (DEX), or normal saline (placebo). Primary outcome was the time to first flatus and/or stool. Secondary outcomes included time to extubation, total analgesic requirement, postoperative pain scores, time to feeds, duration of intensive care unit (ICU) and hospital stay, and the incidence of adverse events. Continuous data were analyzed by the one-way analysis of variance (ANOVA) or the Kruskal–Wallis test. Categorical data were analyzed by the Chi-square test or the Fisher's exact test. Results: Median time to passage of flatus and/or stool was 3 [interquartile range (IQR) 2–3] days in the KET group, 2 [IQR 2–3] days in the DEX group, and 2 [IQR 2–3] days in the placebo group (P = 0.53 for placebo vs. KET, 0.81 for placebo vs. DEX, and 0.99 for KET vs. DEX). Pain scores and analgesic consumption were significantly less in the intervention groups versus placebo (P < 0.001). No difference was seen in other secondary outcomes. Conclusion: Low-dose ketamine or dexmedetomidine did not result in early bowel recovery despite lower pain scores and opioid consumption in patients undergoing open GI malignancy surgeries. [ABSTRACT FROM AUTHOR]

Si thin films with holes are composite materials with interesting optical properties that can be fabricated and modified by state-of-the-art Si process technologies. Adjusting the volumetric air fraction of these films allows control over their effective refractive indices. This work demonstrates a novel scalable method that combines charged sphere colloidal lithography (CSCL) and dry etching to pattern spatially disordered nanoholes in Si thin films. The method can also be adapted to dielectric materials other than silicon. We show controlled tuning of the effective refractive index by lateral dry-etching of the holes. Utilizing this process, a progressive widening of the average hole diameter was obtained, expanding from initial diameters of 60 nm and 100 nm to dimensions reaching 118 nm and 168 nm, respectively. Consequently, the refractive index of the holey films decreased to approximately 2.1 determined via ellipsometry and Bruggeman's model in the near-infrared (NIR) - mid-infrared (MIR) range, in contrast to the unstructured Si refractive index of 3.42. The systematic optical modification was also observed in the reflection spectra of the fabricated films using Fourier-transform infrared spectroscopy (FTIR). Dielectric holey thin films can be attractive for potential applications in MIR photonic devices such as filters and waveguides.

Nuclear receptors function as ligand-regulated transcription factors whose ability to regulate diverse physiological processes is closely linked with conformational changes induced upon ligand binding. Understanding how conformational populations of nuclear receptors are shifted by various ligands could illuminate strategies for the design of synthetic modulators to regulate specific transcriptional programs. Here, we investigate ligand-induced conformational changes using a reconstructed, ancestral nuclear receptor. By making substitutions at a key position, we engineer receptor variants with altered ligand specificities. We combine cellular and biophysical experiments to characterize transcriptional activity, as well as elucidate mechanisms underlying altered transcription in receptor variants. We then use atomistic molecular dynamics (MD) simulations with enhanced sampling to generate ensembles of wildtype and engineered receptors in combination with multiple ligands, followed by conformational analysis and correlation of MD-based predictions with functional ligand profiles. We determine that conformational ensembles accurately describe ligand responses based on observed population shifts. These studies provide a platform which will allow structural characterization of physiologically-relevant conformational ensembles, as well as provide the ability to design and predict transcriptional responses in novel ligands.

Arundo donax L. (Arundinoideae subfamily, Poaceae family) is a sub-tropical and temperate climate reed that grows in arid and semi-arid environmental conditions, from eastern China to the Mediterranean basin, suggesting potential adaptations at the epicuticular level. A thorough physical-chemical examination of the adaxial and abaxial surfaces of A. donax leaf was performed herein in an attempt to track such chemophenetic adaptations. This sort of approach is of the utmost importance for the current debate about the hypothetical invasiveness of this species in the Mediterranean basin versus its natural colonization along the Plio-Pleistocene period. We concluded that the leaf surfaces contain, apart from stomata, prickles, and long, thin trichomes, and silicon-rich tetralobate phytolits. Chemically, the dominating elements in the leaf ashes are oxygen and potassium; minor amounts of calcium, silicon, magnesium, phosphorous, sulphur, and chlorine were also detected. In both surfaces the epicuticular waxes (whose density is higher in the adaxial surface than in the abaxial surface) form randomly orientated platelets, with irregular shape and variable size, and aggregated rodlets with variable diameter around the stomata. In the case of green mature leaves, the dominating organic compounds of the epicuticular waxes of both surfaces are triterpenoids. Both surfaces feature identical hydrophobic behaviour, and exhibit the same total transmittance, total reflectance, and absorption of incident light. The above findings suggest easy growth of the plant, remarkable epidermic robustness of the leaf, and control of water loss. These chemophenetic characteristics and human influence support a neolithization process of this species along the Mediterranean basin.

Urinary tract infections (UTIs) present a significant health challenge for women globally, particularly due to high recurrence rates. This randomized, double-blinded, placebo-controlled study conducted at AIIMS Bhubaneswar, India, evaluated the effectiveness of a multi-strain lactobacilli probiotic formulation as an adjunct to standard antibiotic therapy in preventing recurrent UTIs. Fifty-one adult women (18–50 years) with recurrent UTIs received either the probiotic or a placebo for 24 weeks. The primary outcome was UTI recurrence, while secondary outcomes included the number of UTI episodes and changes in urinary nerve growth factor (NGF) and serum macrophage colony-stimulating factor (M-CSF) levels. The results showed a significant reduction in UTI recurrence in the probiotic group, with 75% remaining recurrence-free, compared to 33% in the placebo group (p = 0.007). The relative risk for recurrence absence was 2.67 (95% CI: 1.19–5.99). Although the mean number of UTI episodes decreased in the probiotic group, the difference was not statistically significant (p = 0.379). The urinary NGF and serum M-CSF levels significantly decreased from baseline in both groups, but there were no significant differences between them. This study suggests probiotics may be a valuable adjunct therapy for preventing recurrent UTIs. [ABSTRACT FROM AUTHOR]

Classically, vicariant phenomena have been essentially identified on the basis of biogeographical and ecological data. Here, we report unequivocal evidences that demonstrate that a physical–chemical characterization of the epicuticular waxes of the surface of plant leaves represents a very powerful strategy to get rich insight into vicariant events. We found vicariant similarity between Cercis siliquastrum L. (family Fabaceae, subfamily Cercidoideae) and Ceratonia siliqua L. (family Fabaceae, subfamily Caesalpinoideae). Both taxa converge in the Mediterranean basin (C. siliquastrum on the north and C. siliqua across the south), in similar habitats (sclerophyll communities of maquis) and climatic profiles. These species are the current representation of their subfamilies in the Mediterranean basin, where they overlap. Because of this biogeographic and ecological similarity, the environmental pattern of both taxa was found to be very significant. The physical–chemical analysis performed on the epicuticular waxes of C. siliquastrum and C. siliqua leaves provided relevant data that confirm the functional proximity between them. A striking resemblance was found in the epicuticular waxes of the abaxial surfaces of C. siliquastrum and C. siliqua leaves in terms of the dominant chemical compounds (1-triacontanol (C30) and 1-octacosanol (C28), respectively), morphology (intricate network of randomly organized nanometer-thick and micrometer-long plates), wettability (superhydrophobic character, with water contact angle values of 167.5 ± 0.5° and 162 ± 3°, respectively), and optical properties (in both species the light reflectance/absorptance of the abaxial surface is significantly higher/lower than that of the adaxial surface, but the overall trend in reflectance is qualitatively similar). These results enable us to include for the first time C. siliqua in the vicariant process exhibited by C. canadensis L., C. griffithii L., and C. siliquastrum.

Abstract Recent studies argue that inhalation of respiratory droplets in indoor environments is one of the significant routes of COVID-19 infection. In many cases, patients are isolated in hospitals and quarantine centers to minimize the spread. However, the rooms allocated to these patients are accessed by health care and sanitization workers a couple of times in a day. Since the expiratory activities release airborne droplets with certain viral load, there is a greater need to study the survival of these droplets in the room of a patient to control the exposure to the accessing people. A bi-compartment and bi-component numerical model is developed to study the survival of these droplets in a room, taking into consideration the deposition rates of the droplets and the ventilation rates in the room. The vital aspects related to the survival of the droplets, such as the effect of the severity of the infection, types of releases, size-dependent deposition and role of ventilation are discussed.