Preparation and characterization of edible films composed of Dioscorea opposita Thunb. mucilage and starch

With the goals of reducing negative environmental impacts and improving the novel food packaging industry, edible films composed of Chinese yam mucilage (DOM) and starch were prepared via a casting method. The films were characterized by analysing the physical, morphological, mechanical and barrier properties, performing a thermal analysis, and finally performing an acute toxicity analysis in rats that ingested the film-forming solutions. Four film samples (F1, F2, F3 and F4) were prepared to evaluate the effects of ultrasound and the addition of sodium carboxymethyl cellulose (CMC) on DOM. DOM films presented a compact and uniform structure without toxicological responses, and the optimal DOM film-forming solution contained 20.0% mucilage, 10.0% starch, 1.0% glycerol, and 2.0% CMC after a 1 h ultrasound treatment. The solubility, swelling degree and water vapour permeability (WVP) of DOM film were 41.11%, 95.03% and 55.30 g mm/m²·d·kPa, respectively. The functional groups analysed by FT-IR and thermal degradation were not affected by the different formulations. Therefore, the non-toxic and bio-degradable films prepared using DOM have the great potential to be used in applications in food packaging.     

Molar volumes of LiI in H2O and D2O solutions; Structural hydration interactions

According to a recent study of the H₂O and D₂O molar volume isotope effect (MVIE) of the alkali metal chloride solutions, neither the standard nor the excess MVIE of the LiCl corresponds to the usual hydrophilic hydration characteristics of the inorganic ions above room temperatures. This phenomenon can not be rationalized by electrostriction, with the collapse of the “loose” tetrahedral (“ice-like”) water structure due to the electrostatic (ion + dipole) interaction.It seemed possible that this unique hydration behaviour of the Li⁺ would be stronger and could reveal further structural information with a less hydrophilic anion than the chloride. Therefore we have determined the MVIE of the LiI as a function of temperature and concentration. The densities of normal and heavy water solutions of LiI have been measured with six-figure precision at T = (288.15, 298.15, and 308.15) K from (0.03 to 4) molal, m, using a vibrating-tube densitometer. The solvent isotope effect on the apparent molar volume, as well as on the solute and solvent partial molar volumes, was evaluated.As expected, with the rationalization of the MVIE of LiI instead of the geometric structural differences of the isotopic solvents, the energetic contributions have to be considered at all the temperatures investigated. At infinite dilution, a high degree of compensation between the reversed influences of the Li⁺ and I^? on the activities of the isotopic solvents determines the MVIE. By increasing concentration, the highly asymmetric energetic interactions of the Li⁺ and the I^? with the solvent apparently result in a “mutual salting-out” effect. At a concentration ≈0.7m, a uniquely abrupt structural rearrangement results in a “solvent-separated ion-pair” solution structure.     

Monitoring of the electrochemical degradation of PEDOT films on gold using the bending beam method

Electrochemical and mechanical properties of thin poly(3,4-ethylenedioxythiophene) films deposited on gold have been investigated in aqueous sulfuric acid and sodium-sulfate solutions. It has been shown that at sufficiently positive electrode potentials, overoxidation of the polymer takes place. In some cases, only small changes could be observed in the shape of cyclic voltammograms taken in the “stability region” before and after overoxidation. In contrast to this, the impedance spectra recorded after overoxidation differed considerably from the impedance spectra of a freshly made electrode. Morphological changes of the polymer caused by overoxidation (degradation) could be detected by using the bending beam method.

     

A model ladder polymer physisorbed on a Lennard-Jones surface

The ladder or band polymer considered here differs from “ordinary” main chain polymers through its strongly elongated cross section as opposed to the usually assumed cylindrical cross section of the latter. This cross sectional shape anisotropy and the attendant anisotropy of the bending stiffness give rise to a competition between the polymer's adsorption energy and its undulation entropy. Following the self-consistent field approach the present work studies the effects due to this competition in terms of the orientation order parameter of the ladder plane and the normal distribution of the polymer with respect to a smooth Lennard-Jones surface. In particular, we show that it is possible to induce abrupt orientation changes of the ladder-plane by only slight variations of the torsion and bending persistence lengths of the polymer or the polymer-surface interaction.     

Biodegradable Multiphase Systems Based on Plasticized Starch: A Review

Abstract

The aim of this review is to show the relationships between the structure, the process, and the properties of biodegradable multiphase systems based on plasticized starch (PLS), the so‐called “thermoplastic starch.” These mutiphase materials are obtained when associating association between plasticized starches and other biodegradable materials, such as biodegradable polyesters [polycaprolactone (PCL), polyhydroxyalkanoates (PHAs), polylactic acid (PLA), polyesteramide (PEA), aliphatic, and aromatic copolyesters], or agro‐materials (ligno‐cellulosic fiber, lignin etc.). Depending on materials (soft, rigid) and the plastic processing system used, various structures (blends, composites, multilayers) can be obtained. The compatibility problematic between these hetero‐materials is analyzed. These starchy products show some interesting properties and have some applications in different fields: packaging, sports, catering, agriculture and gardening, or hygiene.     

A Critique of Literature on Thickeners in Textile Printing

Abstract

“Thickeners” [1,2] used in textile printing are high molecular weight compounds, giving viscous pastes in water. These impart stickiness and plasticity to the printing paste so that it can be applied to a fabric surface without spreading and be capable of maintaining the design outlines even under high pressure. Their main function is to hold or adhere the dye particles in the desired place on the fabric until the transfer of dye into the fabric and its fixation are complete.     

“Electrocapillary” curve on solid metal obtained by holographic interferometry

A new very sensitive method was developed for obtaining the “electrocapillary” curve of a solid metal. The method is based on the measurement of small elastic deformations of a strip caused by the changes of the surface tension forces. For the precise measurement of the strip bending (the radius of curvature) holographic interferometry was applied. It is shown that a change of the surface tension ±0.1 mN m^?1 can be registered. The “electrocapillary” curve of platinum in 0.05 M H₂SO₄ solution was obtained. It was found that the zero charge potential is +0.25 V versus normal hydrogen electrode. The double layer capacity was evaluated. The method is not very sensitive to temperature changes and can be applied in any case when the working electrode (metal strip) is mounted in a transparent glass cell.     

Novel photosensitive resin simultaneously with outstanding cryogenic strength and toughness for digital light processing three-dimensional Printing

With the increased demand for three-dimensional (3D) printing technology in various fields, it is important to develop high-performance resin that could withstand temperature changes to expand their application potential. A new photosensitive oligomer (BDM–DDM–ETPS–GMA) based on epoxy-terminated polyether siloxane (ETPS) and bismaleimide diphenylmethane/4, 4′-diaminodiphenylmethane (BDM–DDM) resin was synthesized and then mixed with other oligomers, reactive diluents, and photoinitiators to prepare a novel 3D printing resin. The results show that the resulting resins exhibit good fluidity and rapid photopolymerization ability, which satisfies the rheological prerequisites of 3D printing resin. Moreover, the incorporation of BDM–DDM–ETPS–GMA can simultaneously improve the cryogenic stiffness and toughness of commercial resin. Specifically, the tensile strength, elongation at break, flexural strength, impact strength, and storage modulus at ?30 °C of modified resin with 15% BDM–DDM–ETPS–GMA are 151.2 MPa, 10.9%, 146.2 MPa, 9.8 kJ/m², and 4,131 MPa, respectively, which are about 2.81, 1.70, 1.37, 1.81, and 1.54 times of that of commercial resin. A synergistic enhancement mechanism is believed to be attributed to these results, which includes the introduced flexible siloxane chain and the rigid bismaleimide structure as well as decreased cross-linking density. These attractive features of modified resins suggest that the method proposed herein is a new approach to develop high-performance 3D printing photosensitive resin simultaneously with outstanding cryogenic strength and toughness and thus has wide application potential in the aerospace, military industry, and other cutting-edge fields.     

On vibrational bonding of IHI

The vibrational bond of IHI is described in analogy to the covalent bond of H₂⁺ by a Born—Oppenheimer-type separation of light (“hydrogenic” ≡ “electronic”) and heavy (“iodines” ≡ “protons”) particle degrees of freedom. Competing potential energy decreases and hydrogen zero-point energy increases (for the IHI antisymmetric stretching and bending modes) yield a minimum in the iodine symmetric stretching mode's potential energy which supports one bound vibrational IHI state.     

Enhancing the performance of a linear Fresnel reflector using nanofluids and internal finned absorber

The objective of this paper is to investigate thermal efficiency enhancement methods in a linear Fresnel reflector (LFR) with evacuated tube receiver. The primary reflectors of the collector are flat mirrors of 27 m² total net aperture, while the secondary reflector has a parabolic shape. The working fluid is Syltherm 800, and the analysis is performed for temperatures up to 650 K. The use of nanofluids and internal fins is the investigated thermal enhancement methods in the receiver of the LFR. The examined nanofluid is Syltherm/CuO for concentrations 2, 4 and 6%, while the examined internal fins are 8 longitudinal fins which are symmetrically located in the absorber. The LFR is examined using nanofluids and pure thermal oil in smooth or finned absorber. According to the final results, the maximum thermal efficiency enhancement is up to 1% and it is greater for higher operating temperature levels. The use of internal fins is better enhancement method compared to the use of nanofluids, while the combination of these two techniques leads to the highest possible performance. For the inlet temperature of 600 K with 200 L min^?1 flow rate, the thermal efficiency enhancement with 4% nanofluid and finned absorber is found 0.82%, while it is found 0.61 and 0.28% with finned absorber with pure oil and 4% nanofluid with smooth absorber, respectively.

     

Features of the Current Sustainment in a Low-Current Discharge in Airflow

The paper relates to the investigations of a low-current discharge in a vortex airflow with the electrode configuration corresponding to classical coaxial plasmatron. The gas flow rate is varied from 0.1 to 0.3 g/s at an inner diameter of the plasmatron nozzle of 5 mm. The discharge is powered by dc voltage via a ballast resistor. Typical averaged current is changed from 0.06 to 0.15 A so that a maximum averaged power dissipated in the discharge amounts to 160 W. In these conditions, a luminous gas region at the plasmatron exit, which in most publications is associated with a plasma jet, is observed. The method for the jet diagnostics based on a usage of the additional electrodes at the plasmatron exit has been proposed. The main idea of the experiments is the elucidation of the problem whether the jet actually represents the plasma area or we have to apply the term “plasma” with care. In particular, in the case under discussion the main charged particles in the jet are electrons that are emitted from a plasma column located in the plasmatron nozzle. The model that describes the formation of electron flow in the jet has been proposed. Typical electron density in the jet estimated with a usage of the model is at a level of 10⁹ cm^?3.

     

Exposure to underground radon in and around Kolkata Municipal Corporation area: an exhaustive study

Air radon survey was carried out at different underground locations at Kolkata using radon monitor. Average radon concentration for basements was found to be 22.70 ± 1.12 Bq/m³ with maximum 59.00 ± 7.18 Bq/m³ and minimum 8.50 ± 3.14 Bq/m³. Average level for sub-ways was 23.05 ± 2.59 Bq/m³ fluctuating between maximum 39.00 ± 1.24 Bq/m³ and minimum 13.50 ± 1.78 Bq/m³. In comparison, open air background at basement entrance was 19.44 ± 1.06 Bq/m³ and subway entrance was 18.58 ± 1.14 Bq/m³. Annual effective dose was calculated to assess probable health risk. Radon concentration level and annual effective dose were found well below safe levels recommended by International Agencies WHO and UNSCEAR.

     

Radical Polymerization of Vinyl Monomers by Hydrophilic Macromolecules. I. Uncatalyzed Polymerization in the Absence of Copper(ll) Ions

Abstract

In 1962 Kimura, Takitani, and Imoto [1] found that an aqueous solution of starch could easily polymerize methyl methacrylate (MMA), and about one-half of the polymerized MMA was grafted on to starch. This novel polymerization was called “uncatalyzed polymerization.” Since then, a large number of macromolecules other than starch have been studied, and many of them are effective for initiating the radical polymerization of MMA.     

Measurement of production date (age) of nanogram amount of uranium

JRC-Karlsruhe obtained a swipe sample from a highly enriched uranium seizure, which had taken place in 2011. Due to the very low amount of uranium (nanograms) a new method needed to be developed to determine the U production date (age). The particles on the swipe were collected on a pyrolytic graphite planchet using a vacuum impactor and they were subsequently leached with ccHNO₃. The “bulk” U isotopic composition (²³⁵U: 72.51?±?0.03 wt%) and the production date (December 1992?±?1 year) determined by MC-ICP-MS indicated that the material showed similarity with two other HEU cases seized earlier in Europe.

     

Degradation of munition wastes byPhanerochaete chrysosporium

“Pink water” is a waste-water stream generated by munitions LAP (loading, assembly, and packing) operations. The major components of this waste water are trinitrotoluene (TNT) and cyclotrimethylene trinitramine (RDX) at concentrations of 120-175 mg/L and 25 mg/L, respectively. Currently, pink water is treated by activated carbon adsorption. Removal efficiencies of >99.5% have been reported. However, this treatment method suffers a serious limitation in that the carbon cannot be safely regenerated. Loaded carbon is disposed of by incineration after a single use.

We have demonstrated that TNT, RDX, simulated, and actual pink water can be effectively treated byPhanerochaete chrysosporium immobilized on the disks of a rotating biological contractor (RBC) in both batch and continuous modes. Greater than 90% removal of TNT from a simulated pink water was observed in a continuous RBC with a residence time of about 24 h. The disk area required was about 10,000 ft²/gpm (4091 m²/m³h) feed. RDX was amenable to treatment, but RDX removal rates were somewhat slower. A full-scale treatment system was designed on the basis of laboratory data, and a cost analysis was performed. This analysis has shown that biotreatment of pink water can be a cost-effective alternative to carbon adsorption.

     

P,N Codoped carbon dots as an efficient “off-on” fluorescent probe for lipoic acid detection and its cellular dual-color imaging

A facile single hydrothermal method was developed to synthetize P,N codoped carbon dots (P,N/CDs), which show strong and stable fluorescence, good water solubility, low toxicity and good biocompatibility. Hence, a novel and efficient “off-on” P,N/CDs fluorescent probe was developed for the highly sensitive detection of lipoic acid (LA) for the first time. The fluorescence of the P,N/CDs was quenched by Cu²⁺ forming a P,N/CDs-Cu²⁺ complex, which acted as the “off” process, but Cu²⁺ could be removed by LA, due to stronger chelating between LA and Cu²⁺, forming a more stable complex, which recovered the fluorescence of the P,N/CDs, in order to achieve the “on” process. Under optimal conditions, the concentration of LA and the increased fluorescence intensity of the P,N/CDs-Cu²⁺ complex displayed a good linear relationship within the range of 0.05–28 μM, with a detection limit (S/N = 3) of 0.02 μM. The established “off-on” fluorescent probe was successfully applied to the analysis of LA in urine samples. The average recoveries were in the range of 98.3–101.5%, with a relative standard deviations of less than 3.1%. In addition, the P,N/CDs were also successfully applied to cellular dual-color imaging of live T24 cells. The results show that the P,N/CDs have great application potential in clinical diagnosis, bioassay and bioimaging.

Graphical abstract

     

Light-Based 3D Printing of Gelatin-Based Biomaterial Inks to Create a Physiologically Relevant In Vitro Fish Intestinal Model

To provide prominent accessibility of fishmeal to the European population, the currently available, time- and cost-extensive feeding trials, which evaluate fish feed, should be replaced. The current paper reports on the development of a novel 3D culture platform, mimicking the microenvironment of the intestinal mucosa in vitro. The key requirements of the model include sufficient permeability for nutrients and medium-size marker molecules (equilibrium within 24 h), suitable mechanical properties (G' < 10 kPa), and close morphological similarity to the intestinal architecture. To enable processability with light-based 3D printing, a gelatin-methacryloyl-aminoethyl-methacrylate-based biomaterial ink is developed and combined with Tween 20 as porogen to ensure sufficient permeability. To assess the permeability properties of the hydrogels, a static diffusion setup is utilized, indicating that the hydrogel constructs are permeable for a medium size marker molecule (FITC-dextran 4 kg mol⁻¹). Moreover, the mechanical evaluation through rheology evidence a physiologically relevant scaffold stiffness (G' = 4.83 ± 0.78 kPa). Digital light processing-based 3D printing of porogen-containing hydrogels results in the creation of constructs exhibiting a physiologically relevant microarchitecture as evidenced through cryo-scanning electron microscopy. Finally, the combination of the scaffolds with a novel rainbow trout (Oncorhynchus mykiss) intestinal epithelial cell line (RTdi-MI) evidence scaffold biocompatibility.     

Fire hazard and heat of combustion of sunflower seed hull pellets

This study is concerned with the investigation of the impact of heat flux on the fire hazard and the effective heat of combustion of sunflower seed hull pellets. Pellets produced by pressing common sunflower seed hulls (Helianthus annuus L.) were investigated. The samples were dried on water content of 0 mass% at a temperature of 103 ± 2 °C. The fire hazard and the heat of combustion have been determined via the cone calorimeter and by the testing procedure per ISO 5660-1:2015 at three heat fluxes (25, 35 and 50 kW m⁻²). The peak heat release rate increases with the increasing of the heat flux from 446 (at a heat flux of 25 kW m⁻²) to 601 kW m⁻² (at a heat flux of 50 kW m⁻²). The carbon monoxide yield lies in the interval from 82.50 (at a heat flux of 25 kW m⁻²) to 154.15 g kg⁻¹ (at a heat flux of 50 kW m⁻²). The effective heat of combustion decreases with the increasing of the heat flux from 15.84 (at a heat flux of 25 kW m⁻²) to 14.58 MJ kg⁻¹ (at a heat flux of 50 kW m⁻²).

     

Spectrophotometric Determination of Palladium with Sodium Ethylene-Bis-Selendglycollate

Abstract

SUMMARY

Palladium was determined spectrophotometrically with sodium ethylene-bis-selenoglycollate in acid medium. The system obeys Beer' law in the range 0.25–0, 3 5 μg.ml^?1 and the molar absorptivity is 2.4 × 10⁴ 1. mol^?1 .cm^?1. Determination of palladium in the presence of many ions is reported.

In spite of the fact that selenium compounds have rarely been used as organic analytical reagents and one finds many palladium determination methods in the literature, this paper fits into the general Purpose reported before ^1,2 :systematic comparison of organic sulphur, sellenium and tellurium compounds as analytical reagents in agreement with propositions made some years agp ^3,4

In previous work⁵ the behaviour of the ethylseleno glycollic (L₁), selenodiglycollic (L₂) and ethylene-bis-selenoglycollic (L₃) anions in acidic solutions of some “soft”, “borderline” and “hard” cations was studied.

The results obtained for Pd(II) afforded evidences that its determination could be run with the three mentioned ligands.

Nevertheless, L₃ was selected because it provides the most sensitive signal and its synthesis is very simple and its overall yield is excellent⁶

From the qualitative study⁵ the foreseen selectivity could present some restrictions, but there is little doubt about the usefulness of the method that will be proposed, in various schemes of determination. Similar comments Beamish have been made about EDTA method for Pd(II) determination⁸