Smart Biopolymer-Based Nanocomposite Materials Containing pH-Sensing Colorimetric Indicators for Food Freshness Monitoring

Nanocomposite biopolymer materials containing colorimetric pH-responsive indicators were prepared from gelatin and chitosan nanofibers. Plant-based extracts from barberry and saffron, which both contained anthocyanins, were used as pH indicators. Incorporation of the anthocyanins into the biopolymer films increased their mechanical, water-barrier, and light-screening properties. Infrared spectroscopy and scanning electron microscopy analysis indicated that a uniform biopolymer matrix was formed, with the anthocyanins distributed evenly throughout them. The anthocyanins in the composite films changed color in response to alterations in pH or ammonia gas levels, which was used to monitor changes in the freshness of packaged fish during storage. The anthocyanins also exhibited antioxidant and antimicrobial activity, which meant that they could also be used to slow down the degradation of the fish. Thus, natural anthocyanins could be used as both freshness indicators and preservatives in biopolymer-based nanocomposite packaging materials. These novel materials may therefore be useful alternatives to synthetic plastics for some food packaging applications, thereby improving the environmental friendliness and sustainability of the food supply.     

Nuclear data for the cyclotron production of ~（117）Sb and ~（90）Nb

This presented study is to make comparison of cross sections to produce ¹¹⁷Sb and ⁹⁰Nb via different reactions with particle incident energy up to 70 MeV as a part of systematic studies on particle-induced activations on enriched Sn, Y₂O₃ and ZrO₂ targets, theoretical calculation of production yield, calculation of required thickness of target and suggestion of optimum reaction to produce Antimony-117 and Niobium-90.     

Synthesis and Characterization of a Fluorescent Water-Borne Polyurethane Based on a Novel Naphthalimide Dye

A waterborne-polyurethane (WPU) dye, based on the fluorescent dye 4-diamino propane-N-allyl-1,8- naphthalimide (WPU-DAN), was synthesized by attaching 4-diamino propane-N-allyl-1,8- naphthalimide (DAN) onto both ends of the polyurethane (PU) chains according to a prepolymer?ionomer process. The synthetic process was confirmed by Fourier transform infrared spectroscopy (FTIR) and UV-visible absorption. The glass transition temperature, molecular weight and average particle sizes were measured. The glass transition temperatures of WPU and WPU-DAN were 46.6 and 49.8°C, respectively. In addition, the particle size distributions of WPU-DAN and WPU were 140 and 134 nm, respectively. The thermal behaviour of WPU-DAN showed improvement compared to WPU. The fluorescence intensity of WPU-DAN was enhanced more than DAN due to the naphthalimide groups attached to the chains, and the fluorescence intensity of WPU-DAN and DAN were increased by increasing temperature. Moreover, the fluorescence intensity of WPU-DAN emulsion was stable during 30 days and no loss of fluorescence intensity occurred for these days.     

Determination of H2S,COS, CS2 and SO2 by an aluminium nitride nanocluster: DFT studies

ABSTRACT

Density functional theory calculations were used to investigate the potential application of an AlN nanocluster in the detection of H₂S, COS, CS₂ and SO₂ gases. In overall, the order of strength of interaction of these gases with the nanocluster is as follows: SO₂ (E_ad?=??17.6?kcal/mol)?>?H₂S (E_ad?=??14.0?kcal/mol)?>?COS (E_ad?=??8.4?kcal/mol)?>?CS₂ (E_ad?=??4.5?kcal/mol). This indicates that by increasing the electric dipole moment, the adsorption energy becomes more negative. We found that the Al₁₂N₁₂ nanocluster may be a promising work function-type sensor for SO₂ gas among the studied gases. Also, it is an electronic sensor for both SO₂ and CS₂ gases but selectively acts between them because of their different effects on the electrical conductivity. It is neither work function-type nor electronic sensor for H₂S and COS gases. The AlN nanocluster benefits from a short recovery time about 7.7?s and 18.0?ms for desorption of SO₂ and CS₂ gases from its surface at room temperature, respectively. It is also concluded that this cluster can work at a humid environment.     

Cu/Ni-doped sulfated zirconium oxide immobilized on CdFe2O4 NPs: a cheap,sustainable and magnetically recyclable inorgano-catalyst for the efficient preparation of α-aminonitriles in aqueous media

Research on Chemical Intermediates - A new multifunctional bimetallic nanocatalyst was prepared by immobilization of Cu/Ni-doped sulfated zirconium oxide on magnetic cadmium ferrite...     

A Versatile Compact Parahydrogen Membrane Reactor

We introduce a Spin Transfer Automated Reactor (STAR) that produces continuous parahydrogen induced polarization (PHIP), which is stable for hours to days. We use the PHIP variant called signal amplification by reversible exchange (SABRE), which is particularly well suited to produce continuous hyperpolarization. The STAR is operated in conjunction with benchtop (1.1 T) and high field (9.4 T) NMR magnets, highlighting the versatility of this system to operate with any NMR or MRI system. The STAR uses semipermeable membranes to efficiently deliver parahydrogen into solutions at nano to milli Tesla fields, which enables ¹H, ¹³C, and ¹⁵N hyperpolarization on a large range of substrates including drugs and metabolites. The unique features of the STAR are leveraged for important applications, including continuous hyperpolarization of metabolites, desirable for examining steady-state metabolism in vivo, as well as for continuous RASER signals suitable for the investigation of new physics.     

Quantum conductance investigation on carbon nanotube–based antibiotic sensor

Journal of Solid State Electrochemistry - Nanostructured carbon material (NSCM) based chemiresistive sensors are popular for sensing different analytes because of their high sensitivity, low cost,...     

Temperature-controlled 'breathing' of carbon dioxide bubbles

We report a microfluidic (MF) approach to studies of temperature mediated carbon dioxide (CO(2)) transfer between the gas and the liquid phases. Micrometre-diameter CO(2) bubbles with a narrow size distribution were generated in an aqueous or organic liquid and subsequently were subjected to temperature changes in the downstream channel. In response to the cooling-heating-cooling cycle the bubbles underwent corresponding contraction-expansion-contraction transitions, which we term 'bubble breathing'. We examined temperature-controlled dissolution of CO(2) in four exemplary liquid systems: deionized water, a 0.7 M aqueous solution of NaCl, ocean water extracted from Bermuda coastal waters, and dimethyl ether of poly(ethylene glycol), a solvent used in industry for absorption of CO(2). The MF approach can be extended to studies of other gases with a distinct, temperature-dependent solubility in liquids.     

Efficient RuIII-catalyzed synthesis of 9-aryl-9H-xanthene-3,6-diols as precursors to fluorones

Efficient condensation of resorcinol and various aromatic aldehydes in the presence of RuCl₃nH₂O as a homogeneous catalyst under reflux conditions was investigated.It was found that a very simple method afforded good to excellent yields of the desired products.     

Automated microfluidic platform for studies of carbon dioxide dissolution and solubility in physical solvents

We present an automated microfluidic (MF) approach for the systematic and rapid investigation of carbon dioxide (CO(2)) mass transfer and solubility in physical solvents. Uniformly sized bubbles of CO(2) with lengths exceeding the width of the microchannel (plugs) were isothermally generated in a co-flowing physical solvent within a gas-impermeable, silicon-based MF platform that is compatible with a wide range of solvents, temperatures and pressures. We dynamically determined the volume reduction of the plugs from images that were accommodated within a single field of view, six different downstream locations of the microchannel at any given flow condition. Evaluating plug sizes in real time allowed our automated strategy to suitably select inlet pressures and solvent flow rates such that otherwise dynamically self-selecting parameters (e.g., the plug size, the solvent segment size, and the plug velocity) could be either kept constant or systematically altered. Specifically, if a constant slug length was imposed, the volumetric dissolution rate of CO(2) could be deduced from the measured rate of plug shrinkage. The solubility of CO(2) in the physical solvent was obtained from a comparison between the terminal and the initial plug sizes. Solubility data were acquired every 5 min and were within 2-5% accuracy as compared to literature data. A parameter space consisting of the plug length, solvent slug length and plug velocity at the microchannel inlet was established for different CO(2)-solvent pairs with high and low gas solubilities. In a case study, we selected the gas-liquid pair CO(2)-dimethyl carbonate (DMC) and volumetric mass transfer coefficients 4-30 s(-1) (translating into mass transfer times between 0.25 s and 0.03 s), and Henry's constants, within the range of 6-12 MPa.