Trends of biofuel cells for smart biomedical devices

Due to the increasing demand for monitoring diseases such as rising heart rate, diabetes, and ocular disorders wearable and implantable biomedical devices seems too essential for patients not only in the hospital but also at home or during working time. Researchers mostly try to offer valuable information on the conditions of patients as non-invasive, by using comfort biomedical device with a minimum side effect. So, small and self-powered with high sensitivity biomedical devices are recommended, among different power sources that introduced for devices, biofuel cells would be produced as power source for a range of medical devices because of its capability to generate sufficient power output compared to the primary power source. The nature of the electrode reaction and the nature of the biochemical reactions are some of the important parameters that are considered for the classification of fuel cells. Enzymatic biofuel cells due to high activity at mild conditions widely applied in pacemaker; glucometer; and smart contact lenses when compared to other kinds of biofuel cells. On the other hand, short lifespan is one of important limitations in this type of biofuel cells. So, the easiest way to overcome these challenges is to apply non-enzymatic ones. Recent studies have attempted to issue novel method for fabrication of non-enzymatic biofuel cell in order to produce a new generation which are inexpensive, disposable, selective, and sensitive in properties. However, consideration of researchers to the development of self-powered biomedical devices by using body fluids or providing electricity storage is rising.     

Cane molasses fermentation for continuous ethanol production in an immobilized cells reactor by Saccharomyces cerevisiae

Sodium-alginate immobilized yeast was employed to produce ethanol continuously using cane molasses as a carbon source in an immobilized cell reactor (ICR). The immobilization of Saccharomyces cerevisiae was performed by entrapment of the cell cultured media harvested at exponential growth phase (16 h) with 3% sodium alginate. During the initial stage of operation, the ICR was loaded with fresh beads of mean diameter of 5.01 mm. The ethanol production was affected by the concentration of the cane molasses (50, 100 and 150 g/l), dilution rates (0.064, 0.096, 0.144 and 0.192 h^?1) and hydraulic retention time (5.21, 6.94, 10.42 and 15.63 h) of the media. The pH of the feed medium was set at 4.5 and the fermentation was carried out at an ambient temperature. The maximum ethanol production, theoretical yield (Y_E/S), volumetric ethanol productivity (Q_P) and total sugar consumption was 19.15 g/l, 46.23%, 2.39 g l^?1 h^?1 and 96%, respectively.     

Gasoline permeation behavior and mechanical properties of polyamide 6/nanoclay,polyamide 6/PE‐g‐maleic anhydride blend,and polyamide 6/PE‐g‐maleic anhydride/clay nanocomposite

In this article, polyamide 6 (PA6)/clay nanocomposites, PA6/polyethylene grafted maleic anhydride (PE‐g‐MA) blends, and PA6/PE‐g‐MA/clay nanocomposites were prepared and their gasoline permeation behavior and some mechanical properties were investigated. In PA6/clay nanocomposites, cloisite 30B was used as nanoparticles, with weight percentages of 1, 3, and 5. The blends of PA6/PE‐g‐MA were prepared with PE‐g‐MA weight percents of 10, 20, and 30. All samples were prepared via melt mixing technique using a twin screw extruder. The results showed that the lowest gasoline permeation occurred when using 3 wt % of nanoclay in PA6/clay nanocomposites, and 10 wt % of PE‐g‐MA in PA6/PE‐g‐MA blends. Therefore, a sample of PA6/PE‐g‐MA/clay nanocomposite containing 3 wt % of nanoclay and 10 wt % of PE‐g‐MA was prepared and its gasoline permeation behavior was investigated. The results showed that the permeation amount of PA6/PE‐g‐MA/nanoclay was 0.41 g m^?2 day^?1, while this value was 0.46 g m^?2 day^?1 for both of PA6/3wt % clay nanocomposite and PA6/10 wt % PE‐g‐MA blend. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40150.     

Effect of cigarette smoke exposure on the growth of Streptococcus mutans and Streptococcus sanguis: an in vitro study.

The aim of the present study was to determine the effect of cigarette smoke on the growth of Streptococcus mutans and Streptococcus sanguis. The standard strains of S. mutans (ATCC 25175) and S. sanguis (ATCC 10556) were cultured on blood agar and incubated for 48 hr in three main environments: atmospheric air, carbon dioxide, and cigarette smoke. Kent gold 1(nicotine: 0.1 mg, tar: 1 mg), Kent lights (nicotine: 0.8 mg, tar: 9 mg) and Bahman (nicotine: 1 mg, tar: 13 mg) were the brands used in the present study. Afterwards, digital photographs of the colonies were taken and the diameter of colonies was measured. Data were analyzed using Post Hoc and General Linear Model statistical tests. Cigarette smoke and carbon dioxide environments significantly increased the growth of S. mutans. However, high nicotine/tar content cigarette smoke (Bahman) had the greatest impact on S. mutans and S. sanguis. The mutans/sanguis ratio, which was 0.71 in atmospheric air, increased to 1.07 in the presence of carbon dioxide. Kent gold 1, Kent lights, and Bahman demonstrated a mutans/sanguis ratio of 1, 0.84, and 0.98 respectively. In conclusion, it seems that the growth of S. sanguis and S. mutans is accelerated in the vicinity of cigarette smoke.     

What Computing with Words Means to Me [Discussion Forum]

Computing with words (CWW) means different things to different people. This article is the start of a position paper, written by some of the members of the CIS Fuzzy Systems Technical Committee Task Force on CWW, that answers the question "What does CWW mean to me?"     

Copper (hydr)oxide modified copper electrode for electrocatalytic oxidation of hydrazine in alkaline media

Stable copper (hydr)oxide modified copper electrode was prepared by cyclic voltammetry in 0.1 M NaOH solution in the potential range of −300 to 800 mV. In the first cycle the oxidation peaks of copper were observed but in the second and next cycles, they were omitted and a clean background was obtained. This indicates that an irreversible electrochemical transformation has been achieved during the first cycle and a stable layer of hydr(oxide) formed on the surface of the copper electrode. This layer protects the electrode from corrosion. This electrode can be used for electrochemical studies in the potential range of −300 to 800 mV without any interfering effects by the oxidation peaks of copper. The modified electrode was used for electrocatalytic oxidation of hydrazine. Results showed that on the bare copper electrode the oxidation peak of 10 mM hydrazine appear at 380 mV while on the copper (hydr)oxide modified copper electrode, it appear at 260 mV. About 120 mV negative shift of the peak potential indicated the catalytic activity of (hydr)oxide layer for hydrazine. The kinetic parameters were investigated by using cyclic voltammetry and chronoamperometry.     

Daily Outflow Prediction by Multi Layer Perceptron with Logistic Sigmoid and Tangent Sigmoid Activation Functions

This paper discusses the use of artificial neural network (ANN) models for predicting daily flows from Khosrow Shirin watershed located in the northwest part of Fars province in Iran. A Multi-Layer Perceptron (MLP) neural network was developed using five input vectors leading to five ANN models: MLP1, MLP2, MLP3, MLP4, and MLP5. Two activation functions were used and they were logistic sigmoid and tangent sigmoid. The MLP_Levenberg–Marquardt (LM) algorithm was used for the training of ANN models. A 5-year data record, selected randomly, was used for ANN training and testing. The predicted outflow showed that the tangent sigmoid activation function performed better than did the logistic sigmoid activation function. The values of R ² and RMSE for MLP4 with the tangent sigmoid activation function for the validation period were equal to 0.89 and 1.7 m³/s, respectively. Appropriate input vectors for MLPs were determined by correlation analysis. It was found that antecedent precipitation and discharge with 1 day time lag as an input vector best predicted daily flows. Also, comparison of MLPs showed that an increase in input data was not always useful.     

Hyperelastic model analysis of stress‐strain behavior in polybutadiene/ethylene‐propylene diene terpolymer nanocomposites

Micromechanics of elastomer nanocomposite samples based on polybutadiene (BR), ethylene‐propylene diene terpolymer (EPDM) hyperelastic matrixes prepared via melt compounding was investigated using uniaxial tensile analysis. Constitutive hyperelastic models, including Polynomial, Yeoh, Ogden, Arruda‐Boyce, and Van der Waals were used to determine material parameters in incompressible isotropic elastic strain‐energy functions on the basis of a nonlinear least squares optimization method by fitting the data obtained from uniaxial classic experiments. Effect of nanoclay (0, 3, 5, 7, and 10 phr) content on the simulation accuracy was investigated. Simulation results compared with the experimental data suggested that the Ogden model as the most consistent model investigated here. J. VINYL ADDIT. TECHNOL., 23:21–27, 2017. © 2015 Society of Plastics Engineers     

Association of coronary artery calcium score and vascular dysfunction in long‐term hemodialysis patients

Long‐term hemodialysis patients are prone to an exceptionally high burden of cardiovascular disease and mortality. The novel temperature‐based technology of digital thermal monitoring (DTM) of vascular reactivity appears associated with the severity of coronary artery disease in asymptomatic population. We hypothesized that in hemodialysis patients, the DTM and coronary artery calcium (CAC) score have a gradient association that follows that of subjects without kidney disease. We examined the cross‐sectional DTM‐CAC associations in a group of long‐term hemodialysis patients, and their 1:1 matched normal counterpart. Area under the curve for temperature (TMP‐AUC), the surrogate of the DTM index of vascular function, was assessed after a 5‐minute arm‐cuff reactive hyperemia test. Coronary calcium score was measured via electron beam computed tomography or multidetector computed tomography scan. We studied 105 randomly recruited hemodialysis patients (age: 58 ± 13 years, 47% men) and 105 age‐ and gender‐matched controls. In hemodialysis patients vs. controls, TMP‐AUC was significantly worse (114 ± 72 vs. 143 ± 80, P = 0.001) and CAC score was higher (525 ± 425 vs. 240 ± 332, P < 0.001). Hemodialysis patients were 14 times more likely to have CAC score >1000 as compared with controls. After adjustment for known confounders, the relative risk for case vs. control for each standard deviation decrease in TMP‐AUC was 1.46 (95% confidence interval: 1.12–1.93, P = 0.007). Vascular reactivity measured via the novel DTM technology is incrementally worse across CAC scores in hemodialysis patients, in whom both measures are even worse than their age‐ and gender‐matched controls. The DTM technology may offer a convenient and radiation‐free approach to risk‐stratify hemodialysis patients.     

Sol–gel synthesis of silicon carbide on silicon pyramids: a promising candidate for supercapacitor electrodes

In this study, Si porous pyramids nanostructures were synthesized by the metal-assisted chemical etching technique. Different KOH concentrations were used to develop high surface area Si porous pyramids for application as supercapacitor electrodes. Field-emission scanning electron microscope (FE-SEM) studies showed that 5% KOH solution will lead to high surface area Si pyramids with a specific capacitance of 90.3 F/cm². Silicon carbide (SiC) thin film was coated on Si pyramids (SiC@Si) using a facile sol–gel method followed by a carbothermal reduction process. Tetraethylorthosilicate and sugar were used as carbon sources. X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR) and FE-SEM analysis were used to characterize the developed SiC@Si samples. The developed SiC@ Si electrode exhibited a high specific capacitance of 135.5 F/cm² at a scan rate of 10 mV/s (in 1 M NaOH electrolyte). The supercapacitor capability of this SiC@Si structure is significantly higher than classical materials. Because of its facile, controllable and efficient synthesis technique, this novel SiC@Si can be considered a very promising candidate for power sources applications.