IR and electrical properties of thin silicon oxynitride films synthesized by ion implantation

Silicon oxynitride (Si_xO_yN_z) layers were synthesized by implanting single-crystal silicon with ¹⁴N₂⁺ and ¹⁶O₂⁺ 30 keV ions in different proportions to doses varying from 1 × 10¹⁷ to 1 × 10¹⁸ ions cm^-2. IR transmission techniques were used to investigate the structural dependence on the total ion dose and on the annealing temperature. Electrical properties, namely the dielectric strength and the current-voltage and capacitance-voltage characteristics, of the ion-beam-synthesized Si_xO_yN_z layers and changes in them after annealing were measured.     

Electrophoretic studies of mixed ligand complexes in solution—copper(II), nickel(II), cobalt(II), uranyl(II) and thorium(IV)—tartarate—nitrilotriacetate

Paper electrophoresis has been used for the study of the equilibria in mixed ligand complex systems in solution. The method is based on the migration of a spot of a metal ion, with the complexants added in the background electrolyte (0.1 M perchloric acid), at a fixed pH. The concentration of one of the complexants [A] is kept constant, while that of second ligand [L] is varied. A graph of—log [L] against mobility is used to obtain information on the formation of the mixed ligand complex, and to calculate the stability constant. Using this technique, the values of overall stability constant of the complex metal—tartarate—nitrilotriacetate have been found to be 10^12.25, 10^5.98, 10^?3.56, and 10^3.74 for Cu(II), Ni(II), Co(II), UO₂(II) and Th(IV) complexes, respectively at μ = 0.1 and temp. = 40°C.     

Influence of the nutrient medium on the total lipid fatty acid composition of Actinomyces canosus

GLC was used to study the composition of endocellular fatty acids of Actinomyces canosus 89 grown on a chemically defined medium and on a complex medium to which various components were added. Total lipids of the culture contain saturated and unsaturated fatty acids, from C13 to C18, with one or two double bonds. Addition of components to the medium stimulated the biosynthesis of myristic, stearic, oleic, and linoleic fatty acids. Changes in the composition of the growth medium modify the ratio between saturated and unsaturated fatty acids of total lipids, increasing the content of unsaturated fatty acids due to a higher rate of synthesis of linoleic and oleic fatty acids. An increase in the content of unsaturated fatty acids is a positive factor because these acids are involved in important physiological functions of both this organism and other living organisms.     

Sodium-restricted diet increases nighttime plasma norepinephrine and impairs sleep patterns in man

Plasma norepinephrine levels in 10 healthy young males were significantly elevated after 3 days of a low sodium (less than 500 mg/day) diet. The low sodium diet was also associated with disturbed sleep patterns: decreased rapid eye movement and slow wave sleep and increased wakefulness. These sleep changes are similar to those seen in normal aged adults, who also undergo elevations of daytime and nighttime plasma norepinephrine. These results suggest the possibility that increased sympathetic nervous system activity may affect sleep patterns, and that therapies altering sympathetic activity may affect sleep.     

In-flash immersion-and-quench of yttria-stabilized zirconia into liquid nitrogen yields an electronic conductor

It is known that once flash has been triggered with furnace heating, specimens can be held in the state of constant flash, or Stage III, outside the furnace at ambient temperature. The flash is maintained by the current flowing through the specimen. We show that this in-flash state is further preserved when the specimen is immersed into liquid nitrogen. Furthermore, we show that the nature of the material existing in Stage III can be quenched by turning off the power to the specimen while it is still in immersion. Normally, during furnace cool, the specimens revert to their original state when the flash is turned off. However, yttria-stabilized zirconia retrieved from in-flash immersion-and-quench is discovered to be electronically conductive at room temperature, at approximately 11 S/m. The conductivity declines somewhat when the specimen is heated slightly above room temperature, suggesting metal-like behavior. These in-flash immersed specimens, with their Stage III structure frozen in place, will enable ex-situ characterization of changes in the crystallographic, chemical, defect and electronic structure induced by flash activation.     

Bicyclic Aziridinium Ions in Azaheterocyclic Chemistry – Preparation and Synthetic Application of 1‐Azoniabicyclo[n.1.0]alkanes

Recent advances in the field of ring‐expansion chemistry, involving 1‐azoniabicyclo[n.1.0]alkane scaffolds (bicyclic aziridinium ions) as key transient intermediates, have made it possible to efficiently construct a broad variety of medium‐ and large‐sized functionalized nitrogen‐containing heterocycles. In this tutorial review, a comprehensive survey of all pathways leading to the generation of 1‐azoniabicyclo[n.1.0]alkanes is provided, as well as a discussion on their subsequent ring expansions to relevant azaheterocycles governed by ring size, substitution pattern, and/or nature of applied nucleophiles.

     

Lymphotactin acts as an innate mucosal adjuvant

Lymphotactin (Lptn) is a C chemokine produced predominantly by NK and CD8-positive (CD8+) T cells including gammadelta TCR-positive (TCR+) intraepithelial lymphocytes. Lptn is chemotactic for NK and T cells and likely plays an important role in maintaining the integrity of the epithelium and in mucosal immune responses. In this study, we characterized the immune responses to OVA given intranasally with Lptn to mice. This regimen enhanced OVA-specific serum Ab responses and Ab titers in mucosal secretions. Lptn also enhanced OVA-specific Ab-forming cells in mucosal and systemic compartments. CD4-positive (CD4+) T cells isolated from mucosal compartments and spleens of mice intranasally immunized with OVA plus Lptn displayed higher OVA-specific proliferative responses and greater synthesis of IFN-gamma, IL-2, IL-4, IL-5, IL-6, and IL-10 than did CD4+ T cells from mice given OVA without Lptn. These studies indicate that Lptn has adjuvant properties and suggest that Lptn present in the mucosa has the potential to enhance mucosal and systemic Ab responses through help provided by Th1- and Th2-type cells to link the initial innate signals of the mucosa with the acquired immune system.     

CuxCo1-xFe2O4 (x = 0.33, 0.67, 1) Spinel Ferrite Nanoparticles Based Thermoplastic Polyurethane Nanocomposites with Reduced Graphene Oxide for Highly Efficient Electromagnetic Interference Shielding

Cu_xCo_1-xFe₂O₄ (x = 0.33, 0.67, 1)-reduced graphene oxide (rGO)-thermoplastic polyurethane (TPU) nanocomposites exhibiting highly efficient electromagnetic interference (EMI) shielding were prepared by a melt-mixing approach using a microcompounder. Spinel ferrite Cu_0.33Co_0.67Fe₂O₄ (CuCoF1), Cu_0.67Co_0.33Fe₂O₄ (CuCoF2) and CuFe₂O₄ (CuF3) nanoparticles were synthesized using the sonochemical method. The CuCoF1 and CuCoF2 exhibited typical ferromagnetic features, whereas CuF3 displayed superparamagnetic characteristics. The maximum value of EMI total shielding effectiveness (SE_T) was noticed to be 42.9 dB, 46.2 dB, and 58.8 dB for CuCoF1-rGO-TPU, CuCoF2-rGO-TPU, and CuF3-rGO-TPU nanocomposites, respectively, at a thickness of 1 mm. The highly efficient EMI shielding performance was attributed to the good impedance matching, conductive, dielectric, and magnetic loss. The demonstrated nanocomposites are promising candidates for a lightweight, flexible, and highly efficient EMI shielding material.     

Multitask Quantum Study of the Curcumin-Based Complex Physicochemical and Biological Properties

Density functional theory (DFT), time-dependent density functional theory (TDDFT), quantum theory of atoms in molecules (QTAIM), and extended transition state natural orbitals for chemical valence (ETS-NOCV) have all been used to investigate the physicochemical and biological properties of curcumin and three complexes, i.e., Cur-M (M = Ni, Cu, and Mg). Based on DFT calculations, the enolic form (Cur-Enol) is more stable than the anti-diketone form (Cur-Anti diketone) favored for complexation. This enolic form stability was explained by the presence of three intramolecular hydrogen bonds according to the QTAIM analysis. Furthermore, the ETS-NOCV technique revealed that the enolic form had more significant antioxidant activity compared with the anti-diketone form. The calculations from the COnductor-like Screening MOdel for Realistic Solvents (COSMO-RS) showed that the dimethyl sulfoxide (DMSO) solvent could dissolve all the curcumin tautomers Cur-Enol, Cur-Anti-diketone and Cur-Cu, Cur-Mg, and Cur-Ni complexes in contrast to benzene, acetone, octanol, ethanol, methanol, and water. Furthermore, except for Cur-Mg, which had a relatively low solubility (14 g/L), all complexes were insoluble in water. Cur-Anti-diketone was considerably more soluble than Cur-Enol in the examined solvents.