Channel Secondary Random Process for Robust Secret Key Generation

The broadcast nature of wireless communications imposes the risk of information leakage to adversarial users or unauthorized receivers. Therefore, information security between intended users remains a challenging issue. Most of the current physical layer security techniques exploit channel randomness as a common source between two legitimate nodes to extract a secret key. In this paper, we propose a new simple technique to generate the secret key. Specifically, we exploit the estimated channel to generate a secondary random process (SRP) that is common between the two legitimate nodes. We compare the estimated channel gain and phase to a preset threshold. The moving differences between the locations at which the estimated channel gain and phase exceed the threshold are the realization of our SRP. We simulate an orthogonal frequency division multiplexing (OFDM) system and show that our proposed technique provides a drastic improvement in the key bit mismatch rate (BMR) between the legitimate nodes when compared to the techniques that exploit the estimated channel gain or phase directly. In addition to that, the secret key generated through our technique is longer than that generated by conventional techniques

Ultrastructural and Molecular Changes in the Developing Small Intestine of the Toad Bufo regularis

The ontogenetic development of the small intestine of the toad Bufo regularis was investigated using twofold approaches, namely, ultrastructural and molecular. The former has been done using transmission electron microscope and utilizing the developmental stages 42, 50, 55, 60, 63, and 66. The most prominent ultrastructural changes were recorded at stage 60 and were more evident at stage 63. These included the appearance of apoptotic bodies/nuclei within the larval epithelium, the presence of macrophages, swollen mitochondria, distorted rough endoplasmic reticulum, chromatin condensation, and irregular nuclear envelop, and the presence of large vacuoles and lysosomes. The molecular investigation involved examining DNA content and fragmentation. The results showed that the DNA content decreased significantly during the metamorphic stages 60 and 63 compared with both larval (50 and 55) and postmetamorphic (66) stages. The metamorphic stages (60 and 63) displayed extensive DNA laddering compared with stages 50, 55, and 66. The percentage of DNA damage was 0.00%, 12.91%, 57.26%, 45.48%, and 4.43% for the developmental stages 50, 55, 60, 63, and 66, respectively. In conclusion, the recorded remodeling of the small intestine represents a model for clarifying the mechanism whereby cell death and proliferation are controlled

Autonomous three-dimensional formation flight for a swarm of unmanned aerial vehicles

This paper investigates the development of a new guidance algorithm for a formation of unmanned aerial vehicles. Using the new approach of bifurcating potential fields, it is shown that a formation of unmanned aerial vehicles can be successfully controlled such that verifiable autonomous patterns are achieved, with a simple parameter switch allowing for transitions between patterns. The key contribution that this paper presents is in the development of a new bounded bifurcating potential field that avoids saturating the vehicle actuators, which is essential for real or safety-critical applications. To demonstrate this, a guidance and control method is developed, based on a six-degreeof-freedom linearized aircraft model, showing that, in simulation, three-dimensional formation flight for a swarm of unmanned aerial vehicles can be achieved

Delocalized states in three-terminal superconductor-semiconductor nanowire devices

We fabricate three-terminal hybrid devices with a nanowire segment proximitized by a superconductor, and with two tunnel probe contacts on either side of that segment. We perform simultaneous tunneling measurements on both sides. We identify some states as delocalized above-gap states observed on both ends, and some states as localized near one of the tunnel barriers. Delocalized states can be traced from zero to finite magnetic fields beyond 0.5 T. In the parameter regime of delocalized states, we search for correlated subgap resonances required by the Majorana zero mode hypothesis. While both sides exhibit ubiquitous low-energy features at high fields, no correlation is inferred. Simulations using a one-dimensional effective model suggest that delocalized states may belong to lower one-dimensional subbands, while the localized states originate from higher subbands. To avoid localization in higher subbands, disorder may need to be further reduced to realize Majorana zero modes.Comment: Original data available at https://zenodo.org/record/395824

Does Attention-deficit/hyperactivity Disorder Increase the Risk of Minor Blunt Head Trauma in Children?

PROBLEM: It is unclear if attention-deficit hyperactivity disorder (ADHD) increases the risk of head trauma in children. METHODS: We conducted a multicenter prospective observational study of children with minor blunt head trauma. Guardians were queried, and medical records were reviewed as to whether the patient had previously been diagnosed with ADHD. Enrolled patients were categorized based on their mechanism of injury, with a comparison of those with motor vehicle collision (MVC) versus non-MVC mechanisms. FINDINGS: A total of 3410 (84%) enrolled children had ADHD status available, and 274 (8.0%; 95% confidence interval, CI: 7.1, 9.0%) had been diagnosed with ADHD. The mean age was 9.2 ± 3.5 years and 64% were males. Rates of ADHD for specific mechanisms of injury were: assaults: 23/131 (17.6%; 95% CI 11.5, 25.2%), automobile versus pedestrian 23/173 (13.3%; 95% CI: 8.6, 19.3%), bicycle crashes 26/148 (17.6%; 95% CI: 11.8, 24.7%), falls 107/1651 (6.5%; 95% 5.3, 7.8%), object struck head 31/421 (7.4%; 5.1, 10.3%), motorized vehicle crashes (e.g., motorcycle, motor scooter) 11/148 (7.4%; 3.8, 12.9%), and MVCs 46/704 (6.5%; 95% CI: 4.8, 8.6%). CONCLUSION: Children with ADHD appear to be at increased risk of head trauma from certain mechanisms of injury including assaults, auto versus pedestrian, and bicycle crashes but are not at an increased risk for falls

Heterogeneous Image-based Classification Using Distributional Data Analysis

Diagnostic imaging has gained prominence as potential biomarkers for early detection and diagnosis in a diverse array of disorders including cancer. However, existing methods routinely face challenges arising from various factors such as image heterogeneity. We develop a novel imaging-based distributional data analysis (DDA) approach that incorporates the probability (quantile) distribution of the pixel-level features as covariates. The proposed approach uses a smoothed quantile distribution (via a suitable basis representation) as functional predictors in a scalar-on-functional quantile regression model. Some distinctive features of the proposed approach include the ability to: (i) account for heterogeneity within the image; (ii) incorporate granular information spanning the entire distribution; and (iii) tackle variability in image sizes for unregistered images in cancer applications. Our primary goal is risk prediction in Hepatocellular carcinoma that is achieved via predicting the change in tumor grades at post-diagnostic visits using pre-diagnostic enhancement pattern mapping (EPM) images of the liver. Along the way, the proposed DDA approach is also used for case versus control diagnosis and risk stratification objectives. Our analysis reveals that when coupled with global structural radiomics features derived from the corresponding T1-MRI scans, the proposed smoothed quantile distributions derived from EPM images showed considerable improvements in sensitivity and comparable specificity in contrast to classification based on routinely used summary measures that do not account for image heterogeneity. Given that there are limited predictive modeling approaches based on heterogeneous images in cancer, the proposed method is expected to provide considerable advantages in image-based early detection and risk prediction.Comment: 16, 2 figures, 3 table

Telocytes and Cajal cells distribution in renal pelvis, ureteropelvic junction (UPJ), and proximal ureter in normal upper urinary tract and UPJ obstruction: reappraisal of the etiology of UPJ obstruction

Background: Telocytes and Cajal cells have been described in human urinary tract and reproductive system in women and men. Telocytes and Cajal cells have been differentiated from other interstitial cells and were described to be an element in smooth muscle conductivity. Previous studies examined the ureteropelvic junction (UPJ) segment in patients with UPJ obstruction (UPJO) and attributed the etiology of UPJO to the low density or absence Cajal cells and telocytes. The present work aimed at the demonstration of the presence and the density of telocytes and Cajal cells in the upper urinary tract (UUT) in cases with normal UUT and UPJO. It included UPJ segment, renal pelvis, and proximal ureter. The morphological pattern of distribution of collagen in relation to smooth muscle was investigated in normal and obstructed UUT. Materials and methods: The study was carried out on 12 surgical specimens, 5 of them represented the normal UUT and underwent nephrectomy for oncological reasons. Seven patients underwent dismembered pyeloplasty for UPJO. Surgical specimens included renal pelvis, UPJ segment, and proximal ureter. They were subjected to standard hematoxylin and eosin stain, Gomori’s trichrome stain, immunohistochemistry (IHC) with c-kit, and transmission electron microscopy (TEM). Results: Telocytes and Cajal cells were demonstrated in the muscular layer of both normal UUT and UPJO with high density in the proximal ureter in normal UUT as well as in UPJO. The UPJ segment in normal UUT had moderate density of Cajal cells and telocytes while in UPJO the cells were scanty or absent. Renal pelvis in normal UUT showed excess density of cells while obstructed renal pelvis showed scanty Cajal cells and telocytes. Ultrastructural study showed the presence of Cajal cells, telocytes, stem cells, fibroblasts, smooth muscle cells, and collagen in different densities and distribution in normal and obstructed UUT. Conclusions: Examination of the UPJ segment of UPJO revealed that Cajal cells and telocytes were scanty or absent, collagen to muscle ratio was high. The low density of Cajal cells and telocytes in the renal pelvis of the obstructed UUT, compared to the normal, points out to the role of the renal pelvis in  the pathogenesis of UPJ obstruction

An environmentally benign antimicrobial nanoparticle based on a silver-infused lignin core

Silver nanoparticles have antibacterial properties, but their use has been a cause for concern because they persist in the environment. Here, we show that lignin nanoparticles infused with silver ions and coated with a cationic polyelectrolyte layer form a biodegradable and green alternative to silver nanoparticles. The polyelectrolyte layer promotes the adhesion of the particles to bacterial cell membranes and, together with silver ions, can kill a broad spectrum of bacteria, including Escherichia coli, Pseudomonas aeruginosa and quaternary-amine-resistant Ralstonia sp. Ion depletion studies have shown that the bioactivity of these nanoparticles is time-limited because of the desorption of silver ions. High-throughput bioactivity screening did not reveal increased toxicity of the particles when compared to an equivalent mass of metallic silver nanoparticles or silver nitrate solution. Our results demonstrate that the application of green chemistry principles may allow the synthesis of nanoparticles with biodegradable cores that have higher antimicrobial activity and smaller environmental impact than metallic silver nanoparticles

The steroid and xenobiotic receptor (SXR), beyond xenobiotic metabolism

The steroid and xenobiotic receptor (SXR) (also known as pregnane X receptor or PXR) is a nuclear hormone receptor activated by a diverse array of endogenous hormones, dietary steroids, pharmaceutical agents, and xenobiotic compounds. SXR has an enlarged, flexible, hydrophobic ligand binding domain (LBD) which is remarkably divergent across mammalian species and SXR exhibits considerable differences in its pharmacology among mammals. The broad response profile of SXR has led to the development of "the steroid and xenobiotic sensor hypothesis". SXR has been established as a xenobiotic sensor that coordinately regulates xenobiotic clearance in the liver and intestine via induction of genes involved in drug and xenobiotic metabolism. In the past few years, research has revealed new and mostly unsuspected roles for SXR in modulating inflammation, bone homeostasis, vitamin D metabolism, lipid homeostasis, energy homeostasis and cancer. The identification of SXR as a xenobiotic sensor has provided an important tool for studying new mechanisms through which diet, chemical exposure, and environment ultimately impact health and disease. The discovery and pharmacological development of new PXR modulators might represent an interesting and innovative therapeutic approach to combat various diseases