Comparing the efficiency of artificial neural networks in sEMG-based simultaneous and continuous estimation of hand kinematics

Surface Electromyography (sEMG) plays a key role in many applications such as control of Human-Machine Interfaces (HMI) and neuromusculoskeletal modeling. It has strongly nonlinear relations to joint kinematics and reflects the subjects’ intention in moving their limbs. Such relations have been traditionally examined by either integrated biomechanics and multi-body dynamics or gesture-based classification approaches. However, these methods have drawbacks that limit their usability. Different from them, joint kinematics can be continuously reconstructed from sEMG via estimation approaches, for instance, the Artificial Neural Networks (ANNs). The Comparison of different ANNs used in different studies is difficult, and in many cases, impossible. The current study focuses on fairly evaluating four types of ANN over the same dataset and conditions in proportional and simultaneous estimation of 15 hand joint angles from 10 sEMG signals. The presented ANNs are Feedforward, Cascade-Forward, Radial Basis Function (RBFNN), and Generalized Regression (GRNN). Each ANN is applied to its special parametric study. All the methods efficiently solved the regression problem of the complex multi-input multi-output bio-system. The RBFNN has the best performance over the others with a 79.80% mean correlation coefficient over all joints, and its accuracy reaches as high as 92.67% in some joints. Interestingly, the highest accuracy over individual joints is 93.46%, which is achieved via the GRNN. The good accuracy suggests that the proposed approaches can be used as alternatives to the previously adopted ones and can be employed effectively to synchronously control multi-degrees of freedom HMI and for general multi-joint kinematics estimation purposes.     

Advances in the Research of Melatonin in Autism Spectrum Disorders: Literature Review and New Perspectives

Abnormalities in melatonin physiology may be involved or closely linked to the pathophysiology and behavioral expression of autistic disorder, given its role in neurodevelopment and reports of sleep-wake rhythm disturbances, decreased nocturnal melatonin production, and beneficial therapeutic effects of melatonin in individuals with autism. In addition, melatonin, as a pineal gland hormone produced from serotonin, is of special interest in autistic disorder given reported alterations in central and peripheral serotonin neurobiology. More specifically, the role of melatonin in the ontogenetic establishment of circadian rhythms and the synchronization of peripheral oscillators opens interesting perspectives to ascertain better the mechanisms underlying the significant relationship found between lower nocturnal melatonin excretion and increased severity of autistic social communication impairments, especially for verbal communication and social imitative play. In this article, first we review the studies on melatonin levels and the treatment studies of melatonin in autistic disorder. Then, we discuss the relationships between melatonin and autistic behavioral impairments with regard to social communication (verbal and non-verbal communication, social interaction), and repetitive behaviors or interests with difficulties adapting to change. In conclusion, we emphasize that randomized clinical trials in autism spectrum disorders are warranted to establish potential therapeutic efficacy of melatonin for social communication impairments and stereotyped behaviors or interests.     

Lipoprotein(a) is an independent risk factor for coronary artery disease in NIDDM patients in South India

OBJECTIVE: Asian Indians have been reported to have very high prevalence rates of coronary artery disease (CAD) in the absence of traditional risk factors. Recently, elevated levels of lipoprotein(a) [Lp(a)] have been reported to be associated with premature CAD in migrant Asian Indians. However, there are very little data regarding Lp(a) in CAD patients from the Indian subcontinent and virtually none in individuals with NIDDM. The objective of this study was to assess the role of Lp(a) as a marker for CAD in South Indian NIDDM patients. RESEARCH DESIGN AND METHODS: We estimated serum Lp(a) in 100 control subjects, 100 NIDDM patients without CAD, and 100 NIDDM patients with CAD. Lp(a) values were transformed into natural logarithms. Statistical analysis included Student's t test, one-way analysis of variance, and chi2 test. Multiple logistic regression analysis was used to identify associations with CAD. RESULTS: Lp(a) levels were significantly higher in NIDDM patients with CAD compared with NIDDM patients without CAD and control subjects (geometric mean 24.6, 15.1, and 19.4 mg/dl, respectively, P < 0.05). Results of logistic regression analysis showed that Lp(a), age, and HDL were associated with CAD. In NIDDM patients with CAD, there was no correlation between Lp(a) and serum cholesterol, triglyceride, or HDL cholesterol levels, but there was a weak association with LDL cholesterol and systolic blood pressure. CONCLUSIONS: The data suggests that serum Lp(a) is an independent risk factor for CAD in NIDDM patients in South India.     

Calcium-fortified beverage supplementation on body composition in postmenopausal women

Background  

We investigated the effects of a calcium-fortified beverage supplemented over 12 months on body composition in postmenopausal women (n = 37, age = 48–75 y).     

Transition metal carbides and nitrides as oxygen reduction reaction catalyst or catalyst support in proton exchange membrane fuel cells (PEMFCs)

Fuel cells are potentially efficient, silent, and environmentally friendly tools for electrical power generation. One of the obstacles facing the development and the commercialization of fuel cells is the dependence on the precious metal catalyst, i.e., Platinum (Pt) and Pt - alloy, especially at the cathode where high catalyst loading used to compensate the sluggish oxygen reduction reaction (ORR). Pt is not only an expensive and rare element but also has insufficient durability. The development of an efficient non-precious catalyst, i.e., electrochemically active, chemically and mechanically stable, and electrically conductive, is one of the basic requirements for the commercialization of fuel cells. The bonding to carbon and nitrogen to form metal carbides and nitrides modify the nature of the d-band of the parent metal, thus improve its catalytic properties relative to the parent metals to be similar to those of group VIII noble metals. In this article, we summarize the progress in the development of the transition metal carbides (TMCs) and transition metals nitrides (TMNs) relative to their application as catalysts for the ORR in fuel cells. The preparation of TMCs and TMNs via different routes which significantly affects its activity is discussed. The ORR catalytic activity of the TMCs and TMNs as a non-precious catalyst or catalyst support in fuel cells is discussed and compared to that of the Pt-based catalyst in this review article. Moreover, the recent progress in the preparation of the nano-sized (which is a critical factor for increasing the activity at low temperature) TMCs and TMNs are discussed.     

Sonochemical assisted preparation of ZnS–ZnO/MCM-41 based on blast furnace slag and electric arc furnace dust for Cr (VI) photoreduction

Iron/steel making industry is a weed that produces large quantities of slag and dust. The objective of the present study was to develop a procedure for obtaining and characterizing photocatalysts derived from this waste for chromium remediation. The MCM-41 was synthesized via sodium silicate (Na₂SiO₃) derived from Blast Furnace Slag (BFS), and ZnO and ZnS were synthesized based on zinc extracted from Electric Arc Furnace Dust (EAFD). Subsequently, ZnO/ZnS were sono-chemically loaded on the MCM-41 and were tested for the Cr (IV) photoreduction. The resultant ZnO, ZnS, MCM-41, and composites were characterized by X-ray diffraction (XRD), Energy-dispersive X-ray spectroscopy (EDX), N2adsorption–desorption isotherms, Fourier-transform infrared (FT-IR) spectrometry, Dynamic Light scattering, and Transmission electron microscopy (TEM), and X-ray photoelectron spectroscopy (XPS). A regular hexagonal structure of typical mesoporous MCM-41 had been proven by small-angle XRD, HRTEM, and N2 adsorption–desorption. The photoreduction activity of ZnS–ZnO/MCM-41 nanocomposite has obvious efficiency compared to ZnO and ZnO/MCM-41, achieving a 94% photoreduction of Cr (VI) in 180 min under UV irradiation. The slight activity loss after 4 cycles (84.7%) reveals the good photoreduction properties of catalysts. Based on these results, ZnS–ZnO/MCM-41 composite material seems to be high efficiency, green, stable, environment, and economical alternative to be used as a photocatalyst for the reduction of Cr (VI).     

Large-vscale hydrogen production and storage technologies: Current status and future directions

Over the past years, hydrogen has been identified as the most promising carrier of clean energy. In a world that aims to replace fossil fuels to mitigate greenhouse emissions and address other environmental concerns, hydrogen generation technologies have become a main player in the energy mix. Since hydrogen is the main working medium in fuel cells and hydrogen-based energy storage systems, integrating these systems with other renewable energy systems is becoming very feasible. For example, the coupling of wind or solar systems hydrogen fuel cells as secondary energy sources is proven to enhance grid stability and secure the reliable energy supply for all times. The current demand for clean energy is unprecedented, and it seems that hydrogen can meet such demand only when produced and stored in large quantities. This paper presents an overview of the main hydrogen production and storage technologies, along with their challenges. They are presented to help identify technologies that have sufficient potential for large-scale energy applications that rely on hydrogen. Producing hydrogen from water and fossil fuels and storing it in underground formations are the best large-scale production and storage technologies. However, the local conditions of a specific region play a key role in determining the most suited production and storage methods, and there might be a need to combine multiple strategies together to allow a significant large-scale production and storage of hydrogen.     

Fluctuations in T cell receptor and pMHC interactions regulate T cell activation

Adaptive immune responses depend on interactions between T cell receptors (TCRs) and peptide major histocompatibility complex (pMHC) ligands located on the surface of T cells and antigen presenting cells (APCs), respectively. As TCRs and pMHCs are often only present at low copy numbers their interactions are inherently stochastic, yet the role of stochastic fluctuations on T cell function is unclear. Here, we introduce a minimal stochastic model of T cell activation that accounts for serial TCR-pMHC engagement, reversible TCR conformational change and TCR aggregation. Analysis of this model indicates that it is not the strength of binding between the T cell and the APC cell per se that elicits an immune response, but rather the information imparted to the T cell from the encounter, as assessed by the entropy rate of the TCR-pMHC binding dynamics. This view provides an information-theoretic interpretation of T cell activation that explains a range of experimental observations. Based on this analysis, we propose that effective T cell therapeutics may be enhanced by optimizing the inherent stochasticity of TCR-pMHC binding dynamics.     

Synthesis of chitosan‐graft‐poly[2‐cyano‐1‐(pyridin‐3‐yl)allyl acrylate] copolymer from a novel monomer,prepared using a Morita–Baylis–Hillman reaction,and characterization of its antimicrobial activity

A novel method has been developed to modify the natural polymer chitosan. The process utilizes a monomer prepared by employing a Morita–Baylis–Hillman (MBH) reaction. Specifically, the vinyl monomer 2‐[hydroxy(pyridin‐3‐yl)methyl]acrylonitrile (HPA) was synthesized using a high‐yielding MBH reaction of acrylonitrile with pyridine‐3‐carboxaldehyde in the presence of 1,4‐diazabicyclo[2.2.2]octane. Conversion of HPA to 2‐cyano‐1‐(pyridin‐3‐yl)allyl acrylate (CPA) was then carried out by reaction of acryloyl chloride. The highly functionalized monomer CPA was grafted onto chitosan through a reaction in 2% acetic acid containing a persulfate and a sulfite (K₂S₂O₈/Na₂SO₃) as redox promoter. An optimal grafting percentage of 123% is obtained when the grafting process is conducted at 60 °C for 4 h employing a 1:0.5 ratio of K₂S₂O₈ and Na₂SO₃ at a concentration of 2.5 × 10^?3 mol L^?1. Chitosan‐graft‐poly[2‐cyano‐1‐(pyridin‐3‐yl)allyl acrylate] graft copolymers, having various grafting percentages, were characterized using Fourier transform infrared, ¹H NMR and ¹³C NMR spectroscopies, X‐ray diffraction, thermogravimetric analysis and scanning electron microscopy. Finally, the results of studies probing the antimicrobial activities of the polymers against selected microorganisms show that the graft copolymers display higher growth inhibition activities against bacteria and fungi than does chitosan. © 2014 Society of Chemical Industry