Structural studies of ambient temperature plastic crystal ion conductors

A number of novel organic ionic compounds based on the pyrrolidinium cation are described which have been found to be ion conductors in their solid states around room temperature. The properties of the compounds are consistent with their exhibiting plastic crystal phases. In order to understand some of the molecular origins of the plastic crystal behaviour and the ion conductivity that it promotes, a number of related compounds based on the imidazolium and ammonium cations are also described which have structural elements in common with the pyrrolidinium cation, but which do not show the plastic behaviour. It is found therefore that the nature of the cation is quite critical to the development of this behaviour. The alkyl methyl pyrrolidinium cation is found to produce plastic crystal phases when the alkyl chains are short, thereby preserving the ability of the cation to rotate with minimal steric hindrance. The ammonium and imidazolium cations of comparable size and structure are less able to produce these plastic phases, in many cases because the low temperature phase proceeds to melt rather than forming a stable rotator phase.

Conductivity, NMR and crystallographic study of N,N,N,N-tetramethylammonium dicyanamide plastic crystal phases : an archetypal ambient temperature plastic electrolyte material

N,N,N,N-Tetramethylammonium dicyanamide (Me₄NDCA) has been examined via differential scanning calorimetry (DSC), thermogravimetric analysis, conductivity, single crystal X-ray diffraction and ¹H nuclear magnetic resonance (NMR) analyses, and was found to be highly conductive in the solid state (σ =10−3 S cm⁻² at 420 K) and to also exhibit unusual plastic crystal behaviour. To investigate the correlation between such behaviour and the occurrence of molecular rotations in the crystal, ¹H NMR second moment measurements are compared with calculated values predicted from the crystal structure. While DSC analysis indicates a number of solid–solid transitions at ambient temperatures, subsequent ¹H NMR analysis of the Me₄N⁺ cation shows that a variety of rotational motions become active at low (<240 K) temperatures, and that such transitions in rotational states occur over a range of temperatures rather than in a sharp transition. Conductivity analysis reveals that between 320 K and 420 K the conductivity increases by more than six orders of magnitude in the solid state, in line with the transition of the Me₄N⁺ cation to a diffusive state, and that other phase transitions observed in this temperature range have no marked effect on the conductivity. Conduction in this solid state is therefore envisaged to involve a vacancy-diffusion model, involving Me₄N⁺ cation vacancies.

Synthesis and properties of ambient temperature molten salts based on the quaternary ammonium ion

The synthesis of 16 tetraalkyl ammonium bis(trifluoromethane sulfonyl) imide salts, (C_nH_2n+1)₄ +N -N (SO₂CF₃)₂ (n = 1, 2, 3, 4),  (C₂H₅)₂(i-C₃H₇)₂ +N -N(SO₂CF₃)₂, (C₂H₅)(CH₃)(i-C₃H₇)₂+N-N(SO₂CF₃)₂, (n-C₇H₁₅)(C₂H₅)i-C₃H₇)₂+N-N(SO₂CF₃)₂ and (C_nH_2n+1)(C_mH_2m+1)₃+N-N(SO₂CF₃)₂ (n = 6,7,8; m = 1, 2, 4) are reported in this paper. Trends in properties of these salts are discussed. The symmetrical tetraalkyl ammonium salts with the bis(trifluoromethyl sulfonyl) imide anion exhibited a lower melting point than that of corresponding ammonium halides. The salts with low symmetry ammonium cations were found to be of generally lower melting point, and many were stable liquids at room temperature. Several of these did not crystallize during cooling below room temperature and exhibited glass transition temperatures in the region of −60 °C∼−80 °C. A comparison of properties between the ammonium imide salts and corresponding trifluoromethane sulfonates is also presented.

N,N-Dimethylpyrrolidinium hydroxide : a highly conductive solid material at ambient temperature

N,N-Dimethylpyrrolidinium hydroxide (P₁₁OH·4H₂O) was found to exhibit high ionic conductivity in the solid state (7 × 10⁻³ S cm⁻¹ at 25°C) and unusual thermal properties, and ²H solid state NMR measurements indicate liquid-like mobility of the deuterium species in the solid state of P₁₁OD·4.5D₂O.

Ambient temperature plastic crystal electrolyte for efficient, all-solid-state dye-sensitized solar cell

Doping the molecular plastic crystal of succinonitrile with solid N-methyl-N-butylpyrrolidinium iodide salt and iodine has produced a highly conductive solid iodide/triiodide conductor. Furthermore, it was employed for a highly efficient, all-solid-state dye-sensitized solar cell.

CoQ10 conveys protection from oxidative stress in plasma but not skeletal muscle

Coenzyme Q10 (CoQ10) is commonly consumed as an antiaging supplement at doses of 30–210 mg/day. The aim of the study was to determine if CoQ10 alters markers of antioxidant status, oxidative damage, and gene expression in aging skeletal muscle. Female guinea pigs aged 26 months were supplemented for 6 weeks with CoQ10 at a human equivalent dose of 10 mg/kg/day. Body weight, plasma CoQ10 concentration, and WBC DNA abasic sites were measured at weeks 0, 2, 4, and 6 of the supplementation period. At the end of supplementation, concentrations of skeletal muscle CoQ10, glutathione, malondialdehyde, protein carbonyls, DNA abasic sites, activities of catalase and glutathione peroxidase, and the gene expression of cyctochrome c oxidase subunits were measured. Dietary supplementation with CoQ10 elevated plasma CoQ10 levels (pre 73 ± 3 nmol/L, post 581 ± 15 nmol/L, P < 0.05) and decreased abasic sites in WBC DNA (pre 16.8 ± 0.5 Ap/100000 bp, post 9.7 ± 0.4 Ap/100000 bp, P < 0.05). In contrast, all of the measures made in skeletal muscle were not different between groups (P > 0.05). These results indicate that dietary supplementation with CoQ10 at a dose of 10 mg/kg/day may be capable of increasing antioxidant protection and reducing oxidative damage in the plasma, but may have no effect in skeletal muscle.

Pervasive limitations : innovating with ambient intelligence (AmI) technologies and restricted absorptive capacity in Australian SME manufacturers

The last 25 years have seen rapid increases in the number and sophistication of technological and process innovations in large manufacturers, producing dramatic improvements in productivity and efficiency. However, smaller manufacturers’ adoption of such innovations has been uneven. Ambient Intelligence (AmI) technologies are being positioned as the next performance and productivity enhancing purchase for manufacturers. This paper defines and gives examples of AmI technologies in current use, summarises AmI technologies of potential interest to small and medium enterprise (SME) manufacturers, and identifies potential impacts of restricted absorptive capacity in SMEs on the adoption of AmI technologies. Comparing two SME manufacturers, one from Germany and one from Australia illustrates a potential application of generic AmI technology based business solutions to a range of SME manufacturers.

Annual high-dose vitamin D3 and mental well-being: randomised controlled trial

Background Epidemiological evidence supports a relationship between vitamin D and mental well-being, although evidence from large-scale placebo-controlled intervention trials is lacking.

Aims To examine if vitamin D supplementation has a beneficial effect on mood in community-dwelling older women; if a single annual large dose of vitamin D has a role in the prevention of depressive symptoms; and if there is an association between serum 25-hydroxyvitamin D levels and mental health.

Method A double-blind, randomised, placebo-controlled trial of women aged 70 or older (the Vital D Study: ISRCTN83409867 and ACTR12605000658617). Participants were randomly assigned to receive 500 000 IU vitamin D3 (cholecalciferol) orally or placebo every autumn/winter for 3–5 consecutive years. The tools utilised at various time points were the General Health Questionnaire, the 12-item Short Form Health Survey, the Patient Global Impression–Improvement scale and the WHO Well-Being Index. Serum 25-hydroxyvitamin D levels were measured in a subset of 102 participants.

Results In this non-clinical population, no significant differences between the vitamin D and placebo groups were detected in any of the measured outcomes of mental health. Serum 25-hydroxyvitamin D levels in the vitamin D group were 41% higher than the placebo group 12 months following their annual dose. Despite this difference, scores from the questionnaires did not differ. Furthermore, there was no interaction between those on antidepressant/anxiety medication at baseline and the treatment groups.

Conclusions The lack of improvement in indices of mental well-being in the vitamin D group does not support the hypothesis that an annual high dose of vitamin D3 is a practical intervention to prevent depressive symptoms in older community-dwelling women.

Effect of CHO ingestion on exercise metabolism and performance in different ambient temperatures

Two series of experiments were conducted to examine the effect of ingesting beverages with differing carbohydrate (CHO) concentrations and osmolalities on metabolism and performance during prolonged exercise in different environmental conditions. In series 1, 12 subjects performed three cycling exercise trials to fatigue at 70% ·VO_2peak in either 33°C(N = 6) (HT1) or 5°C (N = 6) (CT). Subjects ingested either a 14% CHO solution (osmolality = 390 mosmol·l^-1) (HCHO); a 7% CHO solution (330 mosmol·l^-1) (NCHO) or a placebo (90 mosmol·l^-1) (CON1). In series 2, six subjects performed the same three trials at 33°C (HT2), while ingesting either NCHO, a 4.2% CHO solution (240 mosmol·l^-1) (LCHO) or a placebo) (240 mosmol·l^-1) (CON2). Plasma glucose was higher (P < 0.05) in HCHO than NCHO, which in turn was higher (P < 0.05) than CON1 in both CT and HT1. Plasma glucose was lower (P < 0.05) in CON2 compared with NCHO and LCHO in HT2. The fall in plasma volume was greater(P < 0.05) in HCHO than other trials in both CT and HT1 but was not different when comparing the three trials in HT2. Exercise time was not different when comparing the trials in either HT1 or HT2 but was longer(P < 0.05) in NCHO compared with HCHO, which, in turn, was longer(P < 0.05) than CON1 in CT. These data demonstrate that, during prolonged exercise in the heat, fatigue is related to factors other than CHO availability. In addition, during exercise in 5°C a 7% CHO solution is more beneficial for exercise performance than a 14% CHO solution.

Exhaled air temperature as a function of ambient temperature in flying and resting ducks

Exhaled air temperature (T exh) has a paramount effect on respiratory water loss during flight. For migratory birds, low T exh potentially reduces water loss and increases flight range. However, only three studies provide empirical data on T exh during flight. The aim of this study was to record T exh of birds during rest and flight at a range of controlled ambient temperatures (T amb). One wigeon and two teal flew a total of 20 times in a wind tunnel at T amb ranging from 1° to 24°C. T exh during flight did not differ between the two species and was strongly correlated with T amb (T exh=1.036 T amb + 13.426; R²=0.58). In addition, body temperature had a weak positive effect on T exh. At a given T amb, T exh was about 5°C higher during flight than at rest.