Shelf-Life Extension of Fresh Ginger (Zingiberofficinale) by Gamma Irradiation

ABSTRACT: Gamma irradiation was found to extend the shelf life of farm fresh ginger. A 5-kGy radiation dose and 10 °C storage temperature were found to keep peeled ginger samples microbe free and acceptable until 70 d of storage, whereas nonirradiated (control) peeled ginger spoiled within 40 d under similar storage conditions. The decrease in 6-gingerol, the compound responsible for the pungency of ginger, was found to be insignificant after irradiation.     

Modification of Free Volume in Epoxy Adhesive Formulations

Additives are described which modify the free volume available for segmental motion in epoxy adhesives. Such a mechanism can produce an increase in the tensile modulus of conventional epoxy-amine systems of>60% (e.g. to>4.1 GPa) and in tensile strength of>50% (e.g. to 125 MPa), while also producing a ductile mode of failure (stress-strain curve has negative slope before failure). At low strains, a reduction in free volume hinders polymer segmental motion and so increases the modulus. However, these materials also exhibit a very low Poisson's ratio and strains of ca. 5% cause a sufficient increase in free volume that ductile failure can occur. Improvements in low temperature cure properties (e.g. 118 MPa tensile strength at 60°C cure) together with reductions in the coefficient of thermal expansion and water uptake are also reported. These improvements in bulk adhesive properties are shown to translate into improved adhesive joint performance.     

An improved vertical-axis water-current turbine incorporating a channelling device

Water-Current Turbines (WCTs) are non-polluting electricity generation plants that harness the kinetic energy of natural water courses, using several kinds of rotors. At the School of Engineering of the University of Buenos Aires, researchers are developing a WCT whose particular characteristics improve technical and economic performance. A channelling device, integrated into the flotation system, is used to modify flow conditions in the neighbourhood of the rotor. This system was developed from theoretical modelling and small-scale model testing in a hydrodynamic test canal. The principal advantages of this kind of machine include reduced need for fixed civil works, ease of transport and relocation and autonomous, self-regulated operation, and it is expected to be a low-cost and long-lifetime system.     

Locking-free compressible quadrilateral finite elements: Poisson’s ratio-dependent vector interpolants

In any high-quality viscoplastic calculation, the objectivity related to shape and constitutive parameter indifference is desirable, especially when a continuous deformation into concavity is tracked. In the physical x?y frame, quadratic displacement vectors—explicitly coupled via Poisson’s ratio—encompass bar and Euler–Bernoulli beam modes. Analytically, the unique set of shape functions yields nodal loads and the element stiffness matrix from its area and the first and second area moments. Closed-form Mathematica results exhibit full compliance with all requirements of Iron’s patch tests.     

The electrical delivery of a sublimable II–VI compound by vapor transport in carbon nanotubes

Progress in the field of femtogram (10⁻¹⁵ g) mass delivery relies on finding dependable transport vehicles and uncomplicated methods to tailor the deposition of active substances. Here, current-conductive containers consisting of turbostratic carbon nanotubes were used to store a light-emitting ternary alloy and guide its delivery on demand. We found that the electrically-activated delivery process of this sublimable compound, performed inside a transmission electron microscope, was highly dependent on factors such as the substrate type and current injection mode. Furthermore, our observations suggest that the alleged “missing matter” problem is not solely due to surface migration. Besides extending the field of electrical delivery to the realm of functional materials, the extrusion and mass transport of a sublimable II–VI compound demonstrates that it is possible to guide vapor migration using a carbon nanotube support.     

EFFECTS OF COAL SURFACE CHARGE ON THE ADSORPTION AND GASIFICATION ACTIVITIES OF CALCIUM AND POTASSIUM

ABSTRACT

The electrokinetic properties of lignite, subbituminous and bituminous coal particles and their demineralized derivatives have been measured as a function of pH. Compared to the raw coals, demineTalization generally increased the net negative surface charge densities on the coals. Calcium or potassium adsorption (by ion-exchange) onto the demineralized coals was strongly dependent on pH and the surface charge properties of the coals. Metals uptake was very low (0,1-0.4% wt.) in strongly acidic media (～pHl) but increased dramatically as the net negative charge on the coals was increased by increasing the pHs of the coal suspensions to pH 6 or 10. The reactivities of the calcium- ot potassium-loaded chars in carbon dioxide at 800^°C were similarly dependent upon the pHs at which the catalysts were ion-exchanged onto the coals. For the calcium-containing chars, the reactivities increased in the order: pH 6 > “pH 10 > pH 1 while the variation of the gasification rates with potassium loading pH was: pH 6 ～ pH 10 ? pH I. These findings are attributed to differences in the extent of electrostatic interaction between the calcium or potassium ions and the charged coal surface during catalyst loading from solution.     

Identification of residues in the class II-associated Ii peptide (CLIP) region of invariant chain that affect efficiency of MHC class II-mediated antigen presentation in an allele-dependent manner

Invariant chain (Ii) associates with class II MHC molecules and is crucial for Ag presentation by class II molecules. A general explanation for how invariant chain (Ii) associates with polymorphic MHC class II molecules has been suggested by the crystallographic structure of CLIP (class II-associated Ii peptide) complexed with an HLA class II molecule, HLA-DR3. We show here that methionine residues at positions 93 and 99 in Ii are important in MHC class II-mediated Ag presentation, but function in an allele-dependent manner. Introduction of a Met-->Ala mutation at position 99 in Ii (M99AIi) impaired presentation of peptides derived from exogenous proteins by I-Ad and I-Au class II molecules. Mutating Met-->Ala in Ii at position 93 (M93AIi) abrogated presentation by I-Au molecules, but not by I-Ad. Impaired Ag presentation was associated with conformationally altered expression of I-A molecules on the surface of cells expressing mutated Ii. Cell surface CLIP staining and immunoprecipitation studies showed that both I-Ad and I-Au molecules were associated with an increased abundance of Ii peptides, CLIP, in cells expressing mutated Ii. These results show that methionine 93 and methionine 99 play an important physiologic role in Ii association with class II molecules by regulating release of CLIP from class II in the endocytic compartments to allow binding of cognate peptides.     

Microbial Decontamination of Tea (Camellia sinensis) by Gamma Radiation

ABSTRACT:  Processed dry tea leaves are prone to microbial contamination during post-processing handling and storage. The dry tea leaves may thus carry bacteria and fungi of potential health risk to consumers. Also, during storage under high humidity, absorption of moisture may encourage fungal growth and result in caking of the product. Gamma radiation processing was tried as a method for microbial decontamination. A radiation dose of 5 kGy was found to be effective for this purpose. No significant effect was observed on total phenolics in radiation-processed tea leaves. The antioxidant and biological properties of tea such as free radical scavenging activity, inhibition of xanthine oxidase and lipid peroxidation, and superoxide and nitrite scavenging activities were not affected due to radiation treatment within a dose of 10 kGy. The antimicrobial and sensory properties were also unaffected by the radiation treatment.