Real-Time Arabic Sign Language Recognition Using a Hybrid Deep Learning Model.

Sign language is an essential means of communication for individuals with hearing disabilities. However, there is a significant shortage of sign language interpreters in some languages, especially in Saudi Arabia. This shortage results in a large proportion of the hearing-impaired population being deprived of services, especially in public places. This paper aims to address this gap in accessibility by leveraging technology to develop systems capable of recognizing Arabic Sign Language (ArSL) using deep learning techniques. In this paper, we propose a hybrid model to capture the spatio-temporal aspects of sign language (i.e., letters and words). The hybrid model consists of a Convolutional Neural Network (CNN) classifier to extract spatial features from sign language data and a Long Short-Term Memory (LSTM) classifier to extract spatial and temporal characteristics to handle sequential data (i.e., hand movements). To demonstrate the feasibility of our proposed hybrid model, we created a dataset of 20 different words, resulting in 4000 images for ArSL: 10 static gesture words and 500 videos for 10 dynamic gesture words. Our proposed hybrid model demonstrates promising performance, with the CNN and LSTM classifiers achieving accuracy rates of 94.40% and 82.70%, respectively. These results indicate that our approach can significantly enhance communication accessibility for the hearing-impaired community in Saudi Arabia. Thus, this paper represents a major step toward promoting inclusivity and improving the quality of life for the hearing impaired.

The Efficacy of Intercostal Nerve Block in the Management of Postoperative Pain After Costal Cartilage Harvest for Craniofacial Reconstruction Systematic Review and Meta-analysis.

INTRODUCTION: Autologous costal cartilage harvest is a common procedure in craniofacial reconstruction due to its stability, dependability, and diversity. However, such a procedure is associated with severe donor-site pain postoperatively. Therefore, we aim through this study to compare the efficacy of intercostal nerve block in the management of postoperative pain in patients undergoing costal cartilage harvest for craniofacial reconstruction. METHOD: This systematic review was reported according to the Preferred Reporting Items for Systematic Reviews and Meta-analysis (PRISMA) guidelines. The study systematically reviewed MEDLINE, Cochrane, and EMBASE databases without time-limitation. RESULTS: As a result of reviewing the literature, 33 articles were screened by full-text resulting in 14 articles which met our inclusion/exclusion criteria. However, only four high-quality RCT articles were included in the quantitative synthesis (meta-analysis). The findings of this study suggest that there is no significant difference in pain scores between ICNB and control groups at 12, 24, and 48 h postoperatively, both at rest and with coughing. Therefore, both techniques are considered safe and effective. CONCLUSION: Our results show evidence of favorable outcome of preventive donor-site analgesia with ICNB for harvesting autologous costal cartilage in multiple studies. However, the overall outcomes were insignificant between the two arms. NO LEVEL ASSIGNED: This journal requires that authors assign a level of evidence to each submission to which Evidence-Based Medicine rankings are applicable. This excludes Review Articles, Book Reviews, and manuscripts that concern Basic Science, Animal Studies, Cadaver Studies, and Experimental Studies. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266.

Stationary distribution and probability density function of a stochastic SVIS epidemic model with standard incidence and vaccination strategies.

Considering the great effect of vaccination and the unpredictability of environmental variations in nature, a stochastic Susceptible-Vaccinated-Infected-Susceptible (SVIS) epidemic model with standard incidence and vaccination strategies is the focus of the present study. By constructing a series of appropriate Lyapunov functions, the sufficient criterion R 0 s > 1 is obtained for the existence and uniqueness of the ergodic stationary distribution of the model. In epidemiology, the existence of a stationary distribution indicates that the disease will be persistent in a long term. By taking the stochasticity into account, a quasi-endemic equilibrium related to the endemic equilibrium of the deterministic system is defined. By means of the method developed in solving the general three-dimensional Fokker-Planck equation, the exact expression of the probability density function of the stochastic model around the quasi-endemic equilibrium is derived, which is the key aim of the present paper. In statistical significance, the explicit density function can reflect all dynamical properties of an epidemic system. Next, a simple result of disease extinction is obtained. In addition, several numerical simulations and parameter analyses are performed to illustrate the theoretical results. Finally, the corresponding results and conclusions are discussed at the end of the paper.

High Performance Quasi-2D Perovskite Sky-Blue Light-Emitting Diodes Using a Dual-Ligand Strategy.

For quasi-2D perovskite light-emitting diodes, the introduction of insulating bulky cation reduces the charge transport property, leading to lowered brightness and increased turn-on voltage. Herein, a dual-ligand strategy is adopted to prepare perovskite films by using an appropriate ratio of i-butylammonium (iBA) and phenylethylammonium (PEA) as capping ligands. The introduction of iBA enhances the binding energy of the ligands on the surface of the quasi-2D perovskite, and effectively controls the proportion of 2D perovskite to allow more efficient energy transfer, resulting in the great enhancement of the electric and luminescent properties of the perovskite. The photoluminescence (PL) mapping of the perovskite films exhibits that enhanced photoluminescence performance with better uniformity and stronger intensity can be achieved with this dual-ligand strategy. By adjusting the proportion of the two ligands, sky-blue perovskite light-emitting diodes (PeLEDs) with electroluminescence (EL) peak located 485 nm are achieved with a maximum luminance up to 1130 cd m-2 and a maximum external quantum efficiency (EQE) up to 7.84%. In addition, the color stability and device stability are significantly enhanced by using a dual-ligand strategy. This simple and feasible method paves the way for improving the performance of quasi-2D PeLEDs.

Colloidal Behaviors of Two-Dimensional Titanium Carbide in Natural Surface Waters: The Role of Solution Chemistry.

Although two-dimensional titanium carbide (Ti3C2Tx MXene) has emerged as a shining star material in various communities, its environmental behaviors and fate remain unknown. Herein, the colloidal properties and stability of Ti3C2Tx MXene are explored in aquatic systems for the first time, considering the roles of solution chemistry conditions (e.g., pH, ionic types, and strength). It was found that pH had no effect on the stability of Ti3C2Tx in the range of 5.0-11.0, whereas ionic valence and concentrations displayed significant effects on the aggregation behavior of Ti3C2Tx. By employing time-resolved dynamic light scattering measurements, the critical coagulation concentration (CCC) value of Ti3C2Tx was determined to be 12 mM for NaCl. The divalent cations Ca2+ and Mg2+ exhibited higher destabilizing capacity to Ti3C2Tx, as evidenced by the lower CCC values (0.3 and 0.4 mM for CaCl2 and MgCl2, respectively) and faster coagulation rates. Long-term stability studies implied that Ti3C2Tx MXene was less likely to be transported over long distances in the synthetic or natural waters. These findings provided significant insights into the fate and transport of Ti3C2Tx in the aquatic environment.

Stationary distribution and extinction of a stochastic staged progression AIDS model with staged treatment and second-order perturbation.

Focusing on deterministic AIDS model proposed by Hyman (2000) and the detailed data from the World Health Organization (WHO), there are three stages of AIDS process which are described as Acute infection period, Asymptomatic phase and AIDS stage. Our paper is therefore concerned with a stochastic staged progression AIDS model with staged treatment. In view of the complexity of random disturbances, we reasonably take second-order perturbation into consideration for realistic sense. By means of our creative transformation technique and stochastic Lyapunov method, a critical value R 0 H > 1 is firstly obtained for the existence and uniqueness of ergodic stationary distribution to the stochastic system. Not only does it respectively reveal the corresponding dynamical effects of the linear and second-order perturbations to the model, but the unified form of second-order and linear fluctuations is derived. Next, some sufficient conditions about extinction of stochastic system are established in view of the basic reproduction number R 0 . Finally, some examples and numerical simulations are introduced to illustrate our analytical results. In addition, some advantages of our new method and theory are highlighted by comparison with other existing results at the end of this paper.

Dynamical behavior of a higher order stochastically perturbed SIRI epidemic model with relapse and media coverage.

This paper is intended to explore a higher order stochastically perturbed SIRI epidemic model with relapse and media coverage. Firstly, we derive sufficient criteria for the existence and uniqueness of an ergodic stationary distribution of positive solutions to the system by establishing a suitable stochastic Lyapunov function. Then we obtain adequate conditions for complete eradication and wiping out of the infectious disease. In a biological interpretation, the existence of a stationary distribution implies that the disease will prevail and persist in the long term. Finally, the theoretical results are illustrated by computer simulations, including two examples based on real-life disease.

Convincing Synthesis of Atomically Thin, Single-Crystalline InVO4 Sheets toward Promoting Highly Selective and Efficient Solar Conversion of CO2 into CO.

Atomically thin, single-crystalline InVO4 sheets with the uniform thickness of ∼1.5 nm were convincingly synthesized, which was identified with strong, low-angle X-ray diffraction peaks. The InVO4 atomic layer corresponding to 3 unit cells along [110] orientation exhibits highly selective and efficient photocatalytic conversion of CO2 into CO in the presence of water vapor. Surface potential change measurement and liquid photoluminescence decay spectra confirm that the atomically ultrathin structure can shorten the transfer distance of charge carriers from the interior onto the surface and decrease the recombination in body. It thus allows more electrons to survive and accumulate on the surface, which is beneficial for activation and reduction of CO2. In addition, exclusively exposed {110} facet of the InVO4 atomic layer was found to bind the generating CO weakly, facilitating quick desorption from the catalyst surface to form free CO molecules, which provides an ideal platform to catalytically selective CO product.

Metal-organic framework-based materials: superior adsorbents for the capture of toxic and radioactive metal ions.

Highly efficient removal of metal ion pollutants, such as toxic and nuclear waste-related metal ions, remains a serious task from the biological and environmental standpoint because of their harmful effects on human health and the environment. Recently, highly porous metal-organic frameworks (MOFs), with excellent chemical stability and abundant functional groups, have represented a new addition to the area of capturing various types of hazardous metal ion pollutants. This review focuses on recent progress in reported MOFs and MOF-based composites as superior adsorbents for the efficient removal of toxic and nuclear waste-related metal ions. Aspects related to the interaction mechanisms between metal ions and MOF-based materials are systematically summarized, including macroscopic batch experiments, microscopic spectroscopy analysis, and theoretical calculations. The adsorption properties of various MOF-based materials are assessed and compared with those of other widely used adsorbents. Finally, we propose our personal insights into future research opportunities and challenges in the hope of stimulating more researchers to engage in this new field of MOF-based materials for environmental pollution management.

Nanoscale zero-valent iron/magnetite carbon composites for highly efficient immobilization of U(VI).

Nanoscale zerovalent iron/magnetic carbon (NZVI/MC) composites were successfully synthesized by simply calcining yellow pine and iron precursors. NZVI/MC pyrolyzed at 800°C (NZVI/MC800) had a higher percentage of NZVI and displayed better resistance to aggregation and oxidation of NZVI than samples prepared at other temperatures. The NZVI/MC800 material was applied for the elimination of U(VI) from aqueous solutions. The results suggested that the NZVI/MC800 displayed excellent adsorption capacity (203.94 mg/g) toward U(VI). The significant adsorption capacity and fast adsorption kinetics were attributed to the presence of well-dispersed NZVI, which could quickly reduce U(VI) into U(IV), trapping the guest U(IV) in the porous biocarbon matrix. The removal of U(VI) on the NZVI/MC samples was strongly affected by solution pH. The NZVI/MC samples also displayed outstanding reusability for U(VI) removal after multiple cycles. These findings indicate that NZVI/MC has great potential for remediation of wastewater containing U(VI).

Exploring the Aggregation Mechanism of Graphene Oxide in the Presence of Radioactive Elements: Experimental and Theoretical Studies.

In this study, the aggregation kinetics, aggregate morphology, and aggregation mechanisms of graphene oxide (GO) in the presence of Cs+, Sr2+, UO22+, Eu3+, or Th4+ are characterized by using time-resolved dynamic light scattering, transmission electron microscopy (TEM)-element mapping, redispersion of GO aggregates, and density functional theory (DFT) calculations. The destabilization capability of Cs+, Sr2+, UO22+, Eu3+, and Th4+ and the corresponding values of the critical coagulation concentration (CCC) are obtained for the first time. Polyacrylic acid is used as a dispersant to investigate the reversion of GO aggregates induced by various radioactive elements. The combined results of the poly(acrylic acid) effect and TEM-element mapping show that Cs+ induces the aggregation of GO through electric double-layer suppression and weak binding with oxygen-containing functional groups. By employing DFT calculations, we find that the electrostatic potential distribution and the charge transfer rather than coordination with oxygen-containing functional groups control the destabilizing ability of radioactive elements with a higher valence. A comprehensive process of experimental and theoretical studies is considered to better elucidate the colloidal behavior, self-assembly process, application as a novel adsorbent, and environmental risks of GO.

Broadening the Photoresponse to Near-Infrared Region by Cooperating Fullerene and Nonfullerene Acceptors for High Performance Ternary Polymer Solar Cells.

Ternary polymer solar cells (PSCs) based on multiple materials with level matching and complementary absorptions are regarded as an efficient way to overcome the light-harvesting restriction to surpass high-performance binary PSCs. This study introduces the third component, nonfullerene acceptor IEICO, into binary PSC-based PBDTBDD:PC71 BM to fabricate ternary PSC with one donor and two acceptors. By carefully tuning the third component ratio and cathode engineering, the resulting ternary PSC shows a power conversion efficiency of 10.51%, greatly improved in comparison with binary PSCs-based PBDTBDD:PC71 BM (7.86%) and PBDTBDD:IEICO (5.19%). In addition to extended light absorption, the third component IEICO could accelerate charge-carrier transfer, decrease charge recombination, and increase electron collection, resulting from cascade energy levels, and ameliorate the device morphology to increase the contact area of the active layer and cathode buffer layer. This work demonstrates that ternary PSC incorporated with IEICO is a promising structure for producing high performance PSCs.

Low-temperature solution-processed vanadium oxide as hole transport layer for efficient and stable perovskite solar cells.

In recent years, great progress has been achieved in improving the power conversion efficiency (PCE) of organic-inorganic hybrid perovskite solar cells (PSCs), but the stability of PSCs is still an obstacle in their commercialization due to the limitation of efficient and stable hole transport materials. Herein, we demonstrate an alcohol-solution-based low-temperature-processed vanadium oxide (VOx) hole transport layer (HTL) for planar heterojunction PSCs. The good crystallinity and morphology of CH3NH3PbI3 grown on this amorphous VOx film is investigated by scanning electron microscopy (SEM) and X-ray diffraction (XRD) techniques. Due to the suitable and matching energy levels of VOx and CH3NH3PbI3, the holes generated in CH3NH3PbI3 can efficiently transfer to VOx HTL. Furthermore, VOx-HTL-based PSCs yield a PCE value of 14.5% with better stability in comparison with PEDOT:PSS-HTL-based PSCs. These results reveal that the low-temperature-processed VOx films can be employed as the HTL for efficient and stable PSCs.

l-cysteine intercalated layered double hydroxide for highly efficient capture of U(VI) from aqueous solutions.

l-cysteine intercalated Mg/Al layered double hydroxide (Cys-LDH) composites were fabricated and applied for treating the U(VI) contaminated wastewater under various conditions. Interaction mechanisms and adsorption properties were investigated by using batch experiments with spectroscopy analysis. The adsorption isotherms and kinetics were fitted perfectly with the Langmuir isotherm and the pseudo-second-order model, respectively. The significant maximum adsorption capacity of Cys-LDH (211.58 mg/g) compared to LDH was attributed to the larger number of functional groups on Cys-LDH. The presence of humic acid (HA) decreased U(VI) elimination on Cys-LDH at high pH but increased U(VI) removal at low pH. Typically, the presence of various anions (such as NO3-, Cl-, ClO4- and SO42-) did not obviously affect U(VI) adsorption on Cys-LDH, while the coexisted CO32- significantly affected U(VI) elimination. The predominate adsorption were determined to be the formation of Cys-U(VI)-Cys complexes with cysteine in the Cys-LDH interlayers. The results demonstrated that the Cys-LDH are promising adsorbents for efficient elimination and extraction of radionuclides in actual environmental contamination management.

The General Solution of Singular Fractional-Order Linear Time-Invariant Continuous Systems with Regular Pencils.

This paper introduces a general solution of singular fractional-order linear-time invariant (FoLTI) continuous systems using the Adomian Decomposition Method (ADM) based on the Caputo's definition of the fractional-order derivative. The complexity of their entropy lies in defining the complete solution of such systems, which depends on introducing a method of decomposing their dynamic states from their static states. The solution is formulated by converting the singular system of regular pencils into a recursive form using the sequence of transformations, which separates the dynamic variables from the algebraic variables. The main idea of this work is demonstrated via numerical examples.

Lag Synchronization Criteria for Memristor-Based Coupled Neural Networks via Parameter Mismatches Analysis Approach.

This letter focuses on lag synchronization control analysis for memristor-based coupled neural networks with parameter mismatches. Due to the parameter mismatches, lag complete synchronization in general cannot be achieved. First, based on the [Formula: see text]-measure method, generalized Halanay inequality, together with control algorithms, some sufficient conditions are obtained to ensure that coupled memristor-based neural networks are in a state of lag synchronization with an error. Moreover, the error level is estimated. Second, we show that memristor-based coupled neural networks with parameter mismatches can reach lag complete synchronization under a discontinuous controller. Finally, two examples are given to illustrate the effectiveness of the proposed criteria and well support theoretical results.

Macroscopic, Spectroscopic, and Theoretical Investigation for the Interaction of Phenol and Naphthol on Reduced Graphene Oxide.

Interaction of phenol and naphthol with reduced graphene oxide (rGO), and their competitive behavior on rGO were examined by batch experiments, spectroscopic analysis and theoretical calculations. The batch sorption showed that the removal percentage of phenol or naphthol on rGO in bisolute systems was significantly lower than those of phenol or naphthol in single-solute systems. However, the overall sorption capacity of rGO in bisolute system was higher than single-solute system, indicating that the rGO was a very suitable material for the simultaneous elimination of organic pollutants from aqueous solutions. The interaction mechanism was mainly π-π interactions and hydrogen bonds, which was evidenced by FTIR, Raman and theoretical calculation. FTIR and Raman showed that a blue shift of C═C and -OH stretching modes and the enhanced intensity ratios of ID/IG after phenols sorption. The theoretical calculation indicated that the total hydrogen bond numbers, diffusion constant and solvent accessible surface area of naphthol were higher than those of phenol, indicating higher sorption affinity of rGO for naphthol as compared to phenol. These findings were valuable for elucidating the interaction mechanisms between phenols and graphene-based materials, and provided an essential start in simultaneous removal of organics from wastewater.

Plasma-Facilitated Synthesis of Amidoxime/Carbon Nanofiber Hybrids for Effective Enrichment of 238U(VI) and 241Am(III).

Plasma- and chemical-grafted amidoxime/carbon nanofiber hybrids (p-AO/CNFs and c-AO/CNFs) were utilized to remove 238U(VI) and 241Am(III) from aqueous solutions, seawater, and groundwater. Characteristic results indicated more nitrogen-containing groups in p-AO/CNFs compared to c-AO/CNFs. The maximum adsorption capacities of p-AO/CNFs at pH 3.5 and T = 293 K (588.24 mg of 238U(VI)/g and 40.79 mg of 241Am(III)/g from aqueous solutions, respectively) were significantly higher than those of c-AO/CNFs (263.18 and 22.77 mg/g for 238U(VI) and 241Am(III), respectively), which indicated that plasma-grafting was a highly effective, low-cost, and environmentally friendly method. Adsorption of 238U(VI) on AO/CNFs from aqueous solutions was significantly higher than that of 238U(VI) from seawater and groundwater; moreover, AO/CNFs displayed the highest effective selectivity for 238U(VI) compared to the other radionuclides. Adsorption of 238U(VI) onto AO/CNFs created inner-sphere complexes (e.g., U-C shells) as shown by X-ray absorption fine structure analysis, which was supported by surface complexation modeling. Three inner-sphere complexes gave excellent fits to pH-edge and isothermal adsorption of 238U(VI) on the AO/CNFs. These observations are crucial for the utilization of plasma-grafted, AO-based composites in the preconcentration and immobilization of lanthanides and actinides in environmental remediation.

Synchronization stability and pattern selection in a memristive neuronal network.

Spatial pattern formation and selection depend on the intrinsic self-organization and cooperation between nodes in spatiotemporal systems. Based on a memory neuron model, a regular network with electromagnetic induction is proposed to investigate the synchronization and pattern selection. In our model, the memristor is used to bridge the coupling between the magnetic flux and the membrane potential, and the induction current results from the time-varying electromagnetic field contributed by the exchange of ion currents and the distribution of charged ions. The statistical factor of synchronization predicts the transition of synchronization and pattern stability. The bifurcation analysis of the sampled time series for the membrane potential reveals the mode transition in electrical activity and pattern selection. A formation mechanism is outlined to account for the emergence of target waves. Although an external stimulus is imposed on each neuron uniformly, the diversity in the magnetic flux and the induction current leads to emergence of target waves in the studied network.

The Effects of Heteroatoms Si and S on Tuning the Optical Properties of Rhodamine- and Fluorescein-Based Fluorescence Probes: A Theoretical Analysis.

The effects of the incorporated heteroatoms Si and S on tuning the optical properties of rhodamine- and fluorescein-based fluorescence probes is investigated using DFT and time-dependent DFT with four different functionals. As previously proposed, the large redshift (90 nm) produced by a Si atom in both the absorption and emission spectra can be attributed to the σ*-π* conjugation between the σ* orbital of the Si atom and the π* orbital of the adjacent carbon atoms. However, the presence of a Si atom does not alter the fluorescence quenching mechanism of the nonfluorescent forms of the investigated compounds. For the first time, these theoretical results indicate that the n orbital of the S atom plays an important role in determining the optical properties of the nonfluorescent form of rhodamine-based fluorescence probes. It alters the fluorescence quenching mechanism by lowering the energy of the dark nπ* state, which is due to breakage of the C10-S52 bond upon photoexcitation.