Encapsulation of Nanoparticles Using Nitrilotriacetic Acid End‐Functionalized Polystyrenes and Their Application for the Separation of Proteins

The use of nitrilotriacetic acid end‐functionalized polystyrenes (NTA‐PS) as a multifunctional nanocarrier for the aqueous dispersion of CdSe, γ‐Fe₂O₃ and gold nanoparticles (NPs) is described. When the amphiphilic end‐ functionalized polystyrenes and NPs are dissolved together in tetrahydrofuran, the addition of water causes the spontaneous formation of micellar aggregates, resulting in the successful encapsulation and aqueous dispersion of NPs. Transmission electron microscopy (TEM), scanning electron microscopy (SEM), photoluminescence (PL) spectroscopy, and vibrating sample magnetometer (VSM) are used to characterize the structure and properties of the NPs‐containing micellar aggregates (nanocarrier). After complexation of Ni²⁺ with NTA on the surface of the nanocarrier containing γ‐Fe₂O₃, specific binding between Ni‐NTA complex and histidine‐tagged (His‐tagged) proteins enables selective separation of His‐tagged proteins using a magnet.     

Effects of ultrasound on growth, bioconversion of isoflavones and probiotic properties of parent and subsequent passages of Lactobacillus fermentum BT 8633 in biotin-supplemented soymilk

This study aimed to evaluate the effects of ultrasound on Lactobacillus fermentum BT 8633 in parent and subsequent passages based on their growth and isoflavone bioconversion activities in biotin-supplemented soymilk. The treated cells were also assessed for impact of ultrasound on probiotic properties. The growth of ultrasonicated parent cells increased (P < 0.05) by 3.23-9.14% compared to that of the control during fermentation in biotin-soymilk. This was also associated with enhanced intracellular and extracellular (8.4-17.0% and 16.7-49.2%, respectively; P < 0.05) β-glucosidase specific activity, leading to increased bioconversion of isoflavones glucosides to aglycones during fermentation in biotin-soymilk compared to that of the control (P < 0.05). Such traits may be credited to the reversible permeabilized membrane of ultrasonicated parent cells that have facilitated the transport of molecules across the membrane. The growing characteristics of first, second and third passage of treated cells in biotin-soymilk were similar (P > 0.05) to that of the control, where their growth, enzyme and isoflavone bioconversion activities (P > 0.05) were comparable. This may be attributed to the temporary permeabilization in the membrane of treated cells. Ultrasound affected probiotic properties of parent L. fermentum, by reducing tolerance ability towards acid (pH 2) and bile; lowering inhibitory activities against selected pathogens and reducing adhesion ability compared to that of the control (P < 0.05). The first, second and third passage of treated cells did not exhibit such traits, with the exception of their bile tolerance ability which was inherited to the first passage (P < 0.05). Our results suggested that ultrasound could be used to increase bioactivity of biotin-soymilk via fermentation by probiotic L. fermentum FTDC 8633 for the development of functional food.     

Least-Square Collaborative Beamforming Linear Array for Steering Capability in Green Wireless Sensor Networks

This paper presents a collaborative beamforming (CB) technique to organize the sensor node's location in a linear array for green wireless sensor network (WSN) applications. In this method, only selected clusters and active CB nodes are needed each time to perform CB in WSNs. The proposed least-square linear array (LSLA) manages to select nodes to perform as a linear antenna array (LAA), which is similar to and as outstanding as the conventional uniform linear array (ULA). The LSLA technique is also able to solve positioning error problems that exist in the random nodes deployment. The beampattern fluctuations have been analyzed due to the random positions of sensor nodes. Performances in terms of normalized power gains are given. It is demonstrated by a simulation that the proposed technique gives similar performances to the conventional ULA and at the same time exhibits lower complexity.     

Silica aerogel–poly(ethylene‐co‐vinyl acetate) composite for transparent heat retention films

Poly(ethylene‐co‐vinyl acetate) (EVA) plastic films are widely used for solar coverings including photovoltaic modules and commercial greenhouse films, but are poor at controlling heat flow. In this work, silica aerogel (SA) nanogels were examined for preparing transparent heat retention EVA films that block far infrared spectra radiation to maintain heat, without compromising the optical performance of the films. SA nanogels were melt‐mixed using a mini twin‐screw extruder with EVA pellets to form SA/EVA composite, which were pressed into thin films with controlled thickness. The composite films were characterized in terms of optical properties using a variety of analytical methods including FTIR, UV–Vis spectroscopy, electron, confocal, and atomic force microscopy. Both thermicity and thermal conductivity of commercial and experimental SA/EVA films were measured. The results demonstrated that the SA/EVA films gave improved infrared retention compared to commercial thermal plastic films without compromising visible light transmission, showing the potential for this approach in next generation heat retention films. © 2014 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2014 , 52, 927–935     

Quantification of Cannabinoids in Cultivars of Cannabis sp. by Gas Chromatography–Mass Spectrometry

Chromatographia - In the chemical characterization of medically valued Cannabis, the present work has used a gas chromatography (GC) method coupled with mass spectrometry (MS) for identification...     

Low operating temperature of oxygen gas sensor based on undoped and Cr-doped ZnO films

Undoped and doped ZnO with 1 at.% (atomic percentage) chromium (Cr) was synthesized by RF reactive co-sputtering for oxygen gas sensing applications. The prepared films showed a highly c-oriented phase with a dominant (0 0 2) peak at a Bragg angle of around 34.2°. The operating temperature of the prepared ZnO sensor was around 350 °C and shifted to around 250 °C for the doped ZnO sensor which is lower than that of previously reported work. The sensitivity of the sensor toward oxygen gas was enhanced by doping ZnO with 1 at.% Cr. Good stability and repeatability of the sensor were demonstrated when tested under different concentration of oxygen atmosphere.     

Synthesis of primary amines: first homogeneously catalyzed reductive amination with ammonia

[reaction: see text] The synthesis of primary amines via reductive amination of the corresponding carbonyl compounds with aqueous ammonia is achieved for the first time with soluble transition metal complexes. Up to an 86% yield and a 97% selectivity for benzylamines were obtained in the case of various benzaldehydes by using a Rh-catalyst together with water-soluble phosphine and ammonium acetate. In the case of aliphatic aldehydes, a bimetallic catalyst based on Rh/Ir gave improved results.     

Enhanced Ratiometric pH Sensing Using SNAFL-2 on Silver Island Films: Metal-enhanced Fluorescence Sensing

We have explored the opportunities for enhanced ratiometric pH sensing using the well-known carboxy seminaphthofluorescein (SNAFL-2) and silver island films (SiFs). Our results show that the metallic surfaces can provide up to a 40-fold increase in probe fluorescence intensity as compared to nonmetallic surfaces with the same probe coverage. However, while the S/N is significantly better for pH sensing, the emission wavelength ratiometric values are similar to that obtained in solution, due to the fact that the emission of both the acidic and basic forms of the probe are enhanced to similar extents. To the best of our knowledge this is the first report of enhanced ratiometric fluorescence sensing on metallic surfaces.     

Synthesis and structure of Zn7(mu4-O)2(OAc)10(Pz)2(OAc = acetate; Pz = pyrazine)

Reaction of Zn(OAc)(2).2H(2)O with pyrazine in refluxing ethanol gives the unusual heptanuclear complex Zn7(mu4-O)(2)(OAc)(10)(Pz)(2) (1) (OAc = acetate, Pz = pyrazine) in 46% yield. A single-crystal X-ray diffraction study of revealed a central Zn(7) core in which two pseudo-tetrahedral Zn(4) units are joined at a common vertex. The two pyrazine molecules are bound as terminal (eta1) ligands.