Rationally Designed Vanadium Pentoxide as High Capacity Insertion Material for Mg‐Ion

Owing to high energy density and economic viability, rechargeable Mg batteries are considered alternatives to lithium ion batteries. However besides the chevrel phase, none of the conventional inorganic cathode materials demonstrate reversible intercalation/deintercalation of Mg⁺² ions in an anhydrous electrolyte system. The lack of high voltage and high capacity cathode frustrates the realization of Mg batteries. Previous studies indicate that vanadium pentoxide (V₂O₅) has the potential to reversibly insert/extract Mg ions. However, many attempts to utilize V₂O₅ demonstrate limited electrochemical response, due to hindered Mg ion mobility in solid. Here, monodispersed spherical V₂O₅ with a hierarchical architecture is rationally designed, through a facile and scalable approach. The V₂O₅ spheres exhibit initial discharge capacity of 225 mA h g^?1 which stabilizes at ≈190 mA h g^?1 at 10 mA g^?1, much higher than previous reports. The V₂O₅ spheres exhibit specific discharge capacity of 55 mA h g^?1 at moderate current rate (50 mA g^?1) with negligible fading after 50 cycles (≈5%) and 100 cycle (≈13%), while it retains ≈95% columbic efficiency after 100 cycles demonstrating excellent stability during Mg⁺² ion intercalation/deintercalation. Most interestingly, exact phase and morphology are completely retained even after repeated Mg⁺² ion intercalation/deintercalation at different current rates, demonstrating pronounced electrochemical activity in an anhydrous magnesium electrolyte.     

Preservation of cold‐stored guavas influenced by package materials

The objective of this study was to evaluate the influence of package materials on the preservation of cold‐stored ‘Kumagai’ guavas. The treatments were: PO2, co‐extruded polyolephinic film with gas injection (5% O₂/5% CO₂/N₂); PO3, co‐extruded polyolephinic film with gas injection (5% O₂/5% CO₂/N₂); LDPE, linear low density polyethylene film; LDPE‐gas, linear low density polyethylene film with gas injection (3% O₂/8% CO₂/N₂); PVC, polyvinylchloride stretch film; PO1, co‐extruded polyolephinic film and control: non‐packaged guavas. Guavas were stored at 10 ± 1°C/80–90% RH for 21 days, and then transferred to room temperature. Gas composition within the package headspace was analysed during storage and the physical and chemical characteristics of the guavas were evaluated daily during ripening. The modified atmosphere provided by PO1 film was insufficient to promote the benefit of senescence control. Although PVC provided an atmosphere close to that recommended, it did not preserve the colour and pulp firmness. PO2, PO3, LDPE and LDPE‐gas retarded the senescence process of the guavas during 21 days at 10°C plus 2 days at room temperature, but harmed the normal ripening of guavas in some aspects. This can be explained by reduced O₂ and elevated CO₂ levels within these four packages. None of the packages influenced the titratable acidity and the soluble solids, but they did harm ascorbic acid synthesis. Copyright © 2005 John Wiley & Sons, Ltd.     

A comparison of posttraumatic stress disorder in veterans with and without spinal cord injury.

The authors assessed effects of paraplegic and quadriplegic spinal cord injuries (SCls) on posttraumatic stress disorder (PTSD) by comparing severity and prevalence of PTSD in these groups to a sample of controls who experienced traumatic injuries other than SCI. The authors found that veterans with quadriplegia reported significantly less severe current PTSD symptoms than controls who were not significantly different from veterans with paraplegia. These results suggest that sustaining a quadriplegic SCI decreases risk of current PTSD, whereas sustaining a paraplegic SCI is associated with greater risk of PTSD, although the risk is no greater than that incurred from experiencing the trauma itself. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Electrospun poly(ε-caprolactone)/Ca-deficient hydroxyapatite nanohybrids: Microstructure,mechanical properties and cell response by murine embryonic stem cells

Nanohybrid scaffolds mimicking extracellular matrix are promising experimental models to study stem cell behaviour, in terms of adhesion and proliferation. In the present study, the structural characterization of a novel electrospun nanohybrid and the analysis of cell response by a highly sensitive cell type, embryonic stem (ES) cells, are investigated. Ca-deficient hydroxyapatite nanocrystals (d-HAp) were synthesized by precipitation. Fibrous PCL/d-HAp nanohybrids were obtained by electrospinning, d-HAp content ranging between 2 and 55 wt.%. Electrospun mats showed a non-woven architecture, average fiber size was 1.5 ±0.5 μm, porosity 80–90%, and specific surface area 16 m² g^? 1. Up to 6.4 wt.% d-HAp content, the nanohybrids displayed comparable microstructural, mechanical and dynamo-mechanical properties. Murine ES cell response to neat PCL and to nanohybrid PCL/d-HAp (6.4 wt.%) mats was evaluated by analyzing morphological, metabolic and functional markers. Cells growing on either scaffold proliferated and maintained pluripotency markers at essentially the same rate as cells growing on standard tissue culture plates with no detectable signs of cytotoxicity, despite a lower cell adhesion at the beginning of culture. These results indicate that electrospun PCL scaffolds may provide adequate supports for murine ES cell proliferation in a pluripotent state, and that the presence of d-HAp within the mat does not interfere with their growth.     

Tautomerism and Ionisation of 6-Thioxopurin-8-Ones. A Contribution to the Behaviour of 6-Thiopurines

The neutral molecules of 6-thioxopurin-8-ones are present in aqueous solution as lactams-thiolactams. However, 6-SH-tautomers may be present in the anions of the 1- and 9-methyl derivatives. The sequence of dissociation of the NH-groups is 1 → 9 → 7. Ionisation of the 9-NH-group is greatly facilitated in the 3-methyl derivatives, leading to pK values of about 5. Protonation of the 3-methyl derivatives takes place predominantly at N-1 with the formation of “fixed”, amidinium-like, cations. In all other members of the series, protonation involves mainly the 8-oxo group. In 3,9-dimethyl derivatives, the NMR signals of both methyl substituents are markedly deshielded. The behavior of 6-thioxopurin-8-ones resembles that of 6-thiopurines and 6-thioxanthines.     

On the grain boundary network characteristics in a dual phase steel

Journal of Materials Science - The relative areas of interfaces in dual-phase steel containing an equal fraction of ferrite and martensite have been measured and classified according to five...     

Girls' dating behavior as a function of social context and maturation.

Examined how environmental and physical characteristics contribute to the emergence of adolescent girls' dating behavior. The premise was that one set of individual characteristics, pubertal processes, may have more influence on girls' dating behavior in one context than in another, specifically more in girls who attend dance schools than in those who do not. Seventh to ninth grade girls were seen, 59 who were enrolled in national classical ballet company school and 328 who were not. Body image, dating behavior, career aspirations, pubertal status, and maturational timing were assessed via self-report and maternal report. Dancers were less likely to date than nondancers. A Dance/Nondance Group?×?Pubertal Status interaction was found: Premenarcheal dancers had lower dating scores than postmenarcheal dancers, whereas menarcheal status was not related to dating in nondancers. With regard to body image, a Breast Development?×?Dance/Nondance Group interaction was found, with breast development being negatively related to body image in dancers and unrelated in nondancers. Findings are discussed in terms of interactions between environmental and physical characteristics and the goodness of fit between contextual demands and a girl's particular physical characteristics. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The Photodissociation of Ground and Vibrationally Excited Halogenated Alkanes

The dynamics of photodissociation of small halogenated alkanes, in both their ground and vibrationally excited states, is investigated. The yield of H, Cl(²P_2/3), and Cl(²P_1/2) fragments was measured by (2 + 1) resonance-enhanced multiphoton ionization in a time-of-flight mass spectrometer. We report results from the 193 nm photolysis of ground state CHF₂Cl, CH₃CF₂Cl, CH₃CFCl₂, and OH₃Cl and the 237–243 nm photolysis of CH₃Cl excited to the fourth C–H stretch overtone level. The branching ratios depend on the molecular structure, the accessed excited potential surfaces and, as a consequence, on the dissociation dynamics.     

Induction of certain aroma volatiles in feijoa fruit by postharvest application of acetaldehyde or anaerobic conditions

Postharvest application of acetaldehyde (AA) vapour or anaerobic conditions of N₂ or CO₂ for 24 h to hand-picked feijoa (Feijoa sellowiana Berg) fruits caused the accumulation of volatiles, which increased fruit aroma and flavour. The volatiles, AA, ethanol, ethyl acetate and ethyl butyrate, were produced at high concentrations in treated fruit held for 13 days in storage at 20°C whereas in the control fruits the levels remained very low. A sensory panel judged the treated fruits to be sweeter than the controls, although there was no significant difference in the total soluble solids or acidity between the treated and the non-treated feijoas. Treatment with 98% N₂ for 24 h was most effective for volatile production. Moreover, fruits in the N₂ treatment maintained the best appearance after storage for 13 days at 20°C.