Freshwater fish as a dietary source of vitamin A in Cambodia

Vitamin A deficiency is a public health problem among children and women. Common Cambodian fish species were sampled and screened for vitamin A content. Contents of vitamin A-active compounds (all-trans retinol, all-trans dehydroretinol, 13-cis retinol, 13-cis dehydroretinol and β-carotene) were determined by high-performance liquid chromatography in samples of raw, whole fish from 29 fish species and in raw, edible parts from 24 species. Replicate samples were analysed in seven selected species. Two species, Parachela siamensis and Rasbora tornieri had very high vitamin A contents >1500 RAE/100 g raw, whole fish, and six species (Barbodes altus, Barbodes gonionatus, Dermogenys pusilla, Puntioplites proctozysron and Thynnichthys thynnoides) had high contents of 500–1500 RAE/100 g raw, whole fish. Two species, Puntioplites proctozysron and Thynnichthys thynnoides had high vitamin A contents in raw, edible parts, after employing traditional cleaning practices. (RAE: The amount of vitamin A active compounds in food is expressed as retinol activity equivalents (RAE), defined as the bioefficacy relative to all-trans-retinol [ West, C. E., & Eilander, A. (2002). Consequences of revised estimates of carotenoid bioefficacy for the control of vitamin A deficiency in developing countries. Journal of Nutrition, 132, 2920S–2926S]. Dehydroretinoids (vitamin A₂) are not converted to all-trans-retinol but have similar metabolic functions. In this paper, RAE refers to the functional bioefficacy as defined by Brouwer et al. [ Brouwer, I. A., Dusseldorp, M. V., West, C. E., & Steegers-Theunissen, R. P. M. (2001). Bioavailability and bioefficacy of folate and folic acid in man. Nutrition Research Review, 14, 267–293]).     

Cost-effective disposable thiourea film modified copper electrode for capacitive immunosensor

Cost-effective disposable electrodes were fabricated from copper clad laminate, usually used for printed circuit board (PCB) in electronic industries, by using dry film photoresist. Electro-oxidation (anodisation) was employed to obtain a good formation of thiourea film on the electrode surface. The affinity binding pair of carcinoembryonic antigen (CEA) and anti-carcinoembryonic antigen (anti-CEA) was used as a model system. Anti-CEA was immobilized on thiourea film via covalent coupling. This modified electrode was incorporated with a capacitive system for CEA analysis. This capacitive immunosensor provided a linear range between 0.01 and 10 ng ml⁻¹ with a detection limit of 10 pg ml⁻¹. When applied to analyze CEA in serum samples, the results agreed well with the enzyme linked fluorescent assay (ELFA) technique (P > 0.05). The proposed strategy for the preparation of disposable modified copper electrode is very cost effective and simple. Moreover, it provides good reproducibility. This technique can easily be applied to immobilize other biological sensing elements for biosensors development.     

g-C3N4 coated SrTiO3 as an efficient photocatalyst for H2 production in aqueous solution under visible light irradiation

A highly active photocatalyst based on g-C₃N₄ coated SrTiO₃ has been synthesized simply by decomposing urea in the presence of SrTiO₃ at 400 °C. The catalyst demonstrates a high H₂ production rate ∼440 μmol h⁻¹/g catalyst in aqueous solution under visible light irradiation, which is much higher than conventional anion doped SrTiO₃ or physical mixtures of g-C₃N₄ and SrTiO₃. The improved photocatalytic activity can be ascribed to the close interfacial connections between g-C₃N₄ and SrTiO₃ where photo-generated electron and holes are effectively separated. The newly synthesized catalyst also exhibited a stable performance in the repeated experiments.     

Round‐robin measurement intercomparison of c‐Si PV modules among Asian testing laboratories

Because of recent advances in the production and installation of photovoltaic (PV) systems, the international conformity of PV module performance measurement has become increasingly important. The increase in PV production sites is particularly significant in the Asian region. The present paper summarizes and discusses the results of a round‐robin intercomparison of crystalline silicon modules among national laboratories and certified testing laboratories in the Asian region conducted from 2009 to 2011. Most of the values of P_max measured at the different laboratories were within a ±2% range, although some P_max results showed differences of up to about 3%. This result is comparable to that obtained in the recent intercomparison among international laboratories. Possible sources of difference in the measured values of I_sc, V_oc, FF, and P_max are discussed, for further improvement of international conformity in PV measurement technologies. Copyright © 2012 John Wiley & Sons, Ltd.     

High magnetic and ferroelectric properties of BZT-LSM multiferroic composites at room temperature

In this research, the effects of La_0.7Sr_0.3MnO₃ additive on the phase evolution, microstructure, dielectric, ferroelectric and magnetic properties of BaZr_0.07Ti_0.93O₃ ceramics were systematically investigated. The (BaZr_0.07Ti_0.93O₃)/x(La_0.7Sr_0.3MnO₃) or BZT/xLSM (where x?=?0, 5, 10 and 20?mol%) ceramics were prepared via a solid state reaction method. A pure perovskite phase is observed for the samples of x?≤?10?mol%. The M-H hysteresis loops also show an improvement in the magnetic behavior for higher LSM content samples as well as the modified ferroelectric properties. However, the 5?mol% sample exhibited the optimum ferroelectric and ferromagnetic properties with remnant magnetization (M_r) and remanent polarization (P_r) of 2.38?emu/g and 10.5?µC/cm², respectively. The dielectric-temperature curves show that the two phase-transition temperatures as observed for the unmodified BZT ceramic merges into a single phase-transition temperature for the 5?mol% sample and then become flat curves for the 10?mol% sample. In addition, the mechanical properties i.e. Knoop hardness and Young's modulus values increase with increasing LSM content, where Knoop hardness and Young's modulus values for the 20?mol% sample are increased by ~ 45% and ~ 104%, respectively, as compared to the unmodified sample.     

Fractal analysis features for weak and single-channel upper-limb EMG signals

Electromyography (EMG) signals are the electrical manifestations of muscle contractions. EMG signals may be weak or at a low level when there is only a small movement in the major corresponding muscle group or when there is a strong movement in the minor corresponding muscle group. Moreover, in a single-channel EMG classification identifying the signals may be difficult. However, weak and single-channel EMG control systems offer a very convenient way of controlling human–computer interfaces (HCIs). Identifying upper-limb movements using a single-channel surface EMG also has a number of rehabilitation and HCI applications. The fractal analysis method, known as detrended fluctuation analysis (DFA), has been suggested for the identification of low-level muscle activations. This study found that DFA performs better in the classification of EMG signals from bifunctional movements of low-level and equal power as compared to other successful and commonly used features based on magnitude and other fractal techniques.     

Excellent dielectric constants observed in heterogeneous conduction Ba(Zr<Subscript>0.25</Subscript>Ti<Subscript>0.75</Subscript>)O<Subscript>3</Subscript> ceramics doped with Sr(Fe<Subscript>0.5</Subscript>Nb<Subscript>0.5</Subscript>)O<Subscript>3</Subscript>

The (1-x)Ba(Zr_0.25Ti_0.75)O₃-xSr(Fe_0.5Nb_0.5)O₃ or (1-x)BZT-xSFN ceramics have been fabricated via a solid-state reaction technique. All ceramics exhibit a pure phase perovskite with cubic symmetry. The addition of a small amount of SFN (x?=?0.1) produces an obvious change in dielectric behavior. Very high dielectric constants (ε_r?>?164,000 at 1 kHz and temperature?>?150°C) are observed and the value is obviously higher than dielectric constants for Ba(Zr_0.25Ti_0.75)O₃ and Sr(Fe_0.5Nb_0.5)O₃ ceramics. The ferroelectric measurement data suggests that the unmodified sample exhibited a ferroelectric behavior. However, a transformation from a ferroelectric to a relaxor-like behavior is noted with increasing x concentration. Impedance Spectroscopy (IS) analysis indicates that the presence of excellent dielectric constants is due to the heterogeneous conduction in the ceramics after adding SFN, which can be explained in terms of the Maxwell-Wagner polarization mechanism.     

Feature reduction and selection for EMG signal classification

Feature extraction is a significant method to extract the useful information which is hidden in surface electromyography (EMG) signal and to remove the unwanted part and interferences. To be successful in classification of the EMG signal, selection of a feature vector ought to be carefully considered. However, numerous studies of the EMG signal classification have used a feature set that have contained a number of redundant features. In this study, most complete and up-to-date thirty-seven time domain and frequency domain features have been proposed to be studied their properties. The results, which were verified by scatter plot of features, statistical analysis and classifier, indicated that most time domain features are superfluity and redundancy. They can be grouped according to mathematical property and information into four main types: energy and complexity, frequency, prediction model, and time-dependence. On the other hand, all frequency domain features are calculated based on statistical parameters of EMG power spectral density. Its performance in class separability viewpoint is not suitable for EMG recognition system. Recommendation of features to avoid the usage of redundant features for classifier in EMG signal classification applications is also proposed in this study.     

Iron content in common Cambodian fish species: Perspectives for dietary iron intake in poor,rural households

Iron deficiency is the most widespread nutritional disorder in Cambodia. Sixteen Cambodian fish species were screened for iron, zinc and calcium contents. Esomus longimanus has a higher iron content (451 mg Fe/kg dry matter, SD = 155, n = 4) than other species. Iron pools were measured as inorganic iron (I-Fe) by the ferrozine method, haem-bound iron (H-Fe) by the acetone method and total iron (T-Fe) by atomic absorption spectrometry. I-Fe + H-Fe accounted for <50% of T-Fe in E. longimanus, indicating a pool of complex bound, probably high-molecular weight non-haem iron (Hm-Fe). In a field study, thirty rural women were interviewed about traditional use of E. longimanus; their cleaning and cooking practices were observed and the amounts of fish consumed were recorded and meal samples were collected for iron analysis. Calculations based on the iron content and a high bioavailability of Hm-Fe showed that a traditional fish meal, sour soup, covered 45% of the daily iron requirement for women.     

High thermal stability of energy storage density and large strain improvement of lead-free Bi0.5(Na0.40K0.10)TiO3 piezoelectric ceramics doped with La and Zr

Properties of lead-free Bi_0.5-xLa_xNa_0.40K_0.10Ti_0.98Zr_0.02O₃ (x?=?0.000–0.040) ceramics were investigated. All ceramics have a pure perovskite structure. A high energy storage density (～1.00?J/cm³) at room temperature (RT) is noted for the x?=?0.030 sample, while x?=?0.020 and 0.040 samples have very high thermal stability of energy storage density of ～3% (at 75–150?°C). Furthermore, the x?=?0.030 and 0.040 samples have the highest energy storage efficiency (η) value of 94% at 125?°C with high thermal stability (η?=?84–95% at 25–150?°C). The x?=?0.005 sample has high electric field-induced strain (S_max?=?0.42%) and high normalized strain coefficient (d^*₃₃?=?S_max/E_max?=?700?pm/V) with large improvements (～200% and 163% for S_max and d^*₃₃, respectively), as compared to the based composition. This ceramic system has potentials for piezoelectric and/or energy storage density applications.