Dark conglomerate phases of bent-core liquid crystals

Spontaneous or induced chiral symmetry breaking in achiral systems is unusual and understanding the origin of such a phenomenon has been an important area of research for several years. The optically isotropic mesophases exhibited by unconventional liquid crystals are one of the most interesting systems to investigate spontaneous chiral symmetry breaking in liquid crystal mesophases formed by achiral moieties. The dark conglomerate (DC) phases are one such optically isotropic family of phases. In this paper, a detailed account of the tendency of bent-core mesogens to form a variety of polar smectic phases, the formation of DC phases due to layers deformations and the general optical, electrical, physical properties of the DC phases are given. An example of a DC phase which exhibit distinct electro-optic properties is described with the nature of dynamics of the response and physical reasons responsible for such behaviour. The challenges and prospects of the DC phases are discussed for their potential applications in novel devices

Rapidly rotating plane layer convection with zonal flow

The onset of convection in a rapidly rotating layer in which a thermal wind is present is studied. Diffusive effects are included. The main motivation is from convection in planetary interiors, where thermal winds are expected due to temperature variations on the core-mantle boundary. The system admits both convective instability and baroclinic instability. We find a smooth transition between the two types of modes, and investigate where the transition region between the two types of instability occurs in parameter space. The thermal wind helps to destabilise the convective modes. Baroclinic instability can occur when the applied vertical temperature gradient is stable, and the critical Rayleigh number is then negative. Long wavelength modes are the first to become unstable. Asymptotic analysis is possible for the transition region and also for long wavelength instabilities, and the results agree well with our numerical solutions. We also investigate how the instabilities in this system relate to the classical baroclinic instability in the Eady problem. We conclude by noting that baroclinic instabilities in the Earth's core arising from heterogeneity in the lower mantle could possibly drive a dynamo even if the Earth's core were stably stratified and so not convecting.Comment: 20 pages, 7 figure

Dietary nitrate accelerates postexercise muscle metabolic recovery and O2 delivery in hypoxia.

We tested the hypothesis that the time constants (τ) of postexercise T2* MRI signal intensity (an index of O2 delivery) and muscle [PCr] (an index of metabolic perturbation, measured by (31)P-MRS) in hypoxia would be accelerated after dietary nitrate (NO3 (-)) supplementation. In a double-blind crossover design, eight moderately trained subjects underwent 5 days of NO3 (-) (beetroot juice, BR; 8.2 mmol/day NO3 (-)) and placebo (PL; 0.003 mmol/day NO3 (-)) supplementation in four conditions: normoxic PL (N-PL), hypoxic PL (H-PL; 13% O2), normoxic NO3 (-) (N-BR), and hypoxic NO3 (-) (H-BR). The single-leg knee-extension protocol consisted of 10 min of steady-state exercise and 24 s of high-intensity exercise. The [PCr] recovery τ was greater in H-PL (30 ± 4 s) than H-BR (22 ± 4 s), N-PL (24 ± 4 s) and N-BR (22 ± 4 s) (P 0.05). These findings suggest that the NO3 (-)-NO2 (-)-NO pathway is a significant modulator of muscle energetics and O2 delivery during hypoxic exercise and subsequent recovery.J. Fulford's salary was supported via National Institute of Health Research Grant 50112

On the mechanism by which dietary nitrate improves human skeletal muscle function.

Inorganic nitrate is present at high levels in beetroot and celery, and in green leafy vegetables such as spinach and lettuce. Though long believed inert, nitrate can be reduced to nitrite in the human mouth and, further, under hypoxia and/or low pH, to nitric oxide. Dietary nitrate has thus been associated favorably with nitric-oxide-regulated processes including blood flow and energy metabolism. Indeed, the therapeutic potential of dietary nitrate in cardiovascular disease and metabolic syndrome-both aging-related medical disorders-has attracted considerable recent research interest. We and others have shown that dietary nitrate supplementation lowers the oxygen cost of human exercise, as less respiratory activity appears to be required for a set rate of skeletal muscle work. This striking observation predicts that nitrate benefits the energy metabolism of human muscle, increasing the efficiency of either mitochondrial ATP synthesis and/or of cellular ATP-consuming processes. In this mini-review, we evaluate experimental support for the dietary nitrate effects on muscle bioenergetics and we critically discuss the likelihood of nitric oxide as the molecular mediator of such effects

Protected areas in forest conservation: Challenges and opportunities

Forest ecosystems are important habitats for a vast number of species worldwide [...]</jats:p

Peripheral blood eosinophils: a surrogate marker for airway eosinophilia in stable COPD.

INTRODUCTION: Sputum eosinophilia occurs in approximately one-third of stable chronic obstructive pulmonary disease (COPD) patients and can predict exacerbation risk and response to corticosteroid treatments. Sputum induction, however, requires expertise, may not always be successful, and does not provide point-of-care results. Easily applicable diagnostic markers that can predict sputum eosinophilia in stable COPD patients have the potential to progress COPD management. This study investigated the correlation and predictive relationship between peripheral blood and sputum eosinophils. It also examined the repeatability of blood eosinophil counts. METHODS: Stable COPD patients (n=141) were classified as eosinophilic or noneosinophilic based on their sputum cell counts (≥3%), and a cross-sectional analysis was conducted comparing their demographics, clinical characteristics, and blood cell counts. Receiver operating characteristic curve analysis was used to assess the predictive ability of blood eosinophils for sputum eosinophilia. Intraclass correlation coefficient was used to examine the repeatability of blood eosinophil counts. RESULTS: Blood eosinophil counts were significantly higher in patients with sputum eosinophilia (n=45) compared to those without (0.3×10(9)/L vs 0.15×10(9)/L; P<0.0001). Blood eosinophils correlated with both the percentage (ρ=0.535; P<0.0001) and number of sputum eosinophils (ρ=0.473; P<0.0001). Absolute blood eosinophil count was predictive of sputum eosinophilia (area under the curve =0.76, 95% confidence interval [CI] =0.67-0.84; P<0.0001). At a threshold of ≥0.3×10(9)/L (specificity =76%, sensitivity =60%, and positive likelihood ratio =2.5), peripheral blood eosinophil counts enabled identification of the presence or absence of sputum eosinophilia in 71% of the cases. A threshold of ≥0.4×10(9)/L had similar classifying ability but better specificity (91.7%) and higher positive likelihood ratio (3.7). In contrast, ≥0.2×10(9)/L offered a better sensitivity (91.1%) for ruling out sputum eosinophilia. There was a good agreement between two measurements of blood eosinophil count over a median of 28 days (intraclass correlation coefficient =0.8; 95% CI =0.66-0.88; P<0.0001). CONCLUSION: Peripheral blood eosinophil counts can help identify the presence or absence of sputum eosinophilia in stable COPD patients with a reasonable degree of accuracy

A pilot study evaluating the effects of a 12 week exergaming programme on body mass, size and composition in postpartum females

Introduction: Pregnancy is associated with weight gain, the retention of which contributes to the prevalence of obesity and overweight in adult females. Many new mothers do not achieve the recommendations for physical activity (PA), citing factors such as a lack of time and access to childcare. Exergaming may address some of the barriers to PA and offer an alternative to traditional exercise, thus aiding in weight management. The aim of this pilot study was to evaluate the effects of an exergaming intervention on body composition in postpartum females. Methods: Eight females who had given birth within 1 year completed a 12 week exergaming intervention, which required them to exercise at home for 45 minutes on alternate days, using the Wii Fit. Participants self-reported their pre-pregnancy body weight, and visited the laboratory prior to and following the intervention for evaluation of body weight, size (height, regional circumferences, body mass index [BMI]) and composition (fat mass [FM], lean mass [LM] and bone mineral content [BMC]). Body composition was evaluated via full body full-body dual-energy x-ray absorptiometry scan. Participants completed a three-day weighed food intake at three time-points. Results: Baseline body mass was 8.2 kg greater than self-reported pre-pregnancy values (56.8 ± 5.1 kg). Following the intervention, body mass was significantly lower than baseline values and was similar to pre-pregnancy levels (59.9 ± 7.9 kg). Reductions in BMI (~2 kg·m2 ), waist, hip and bust circumference (3-6%) accompanied the loss of body mass. Food diaries confirmed participants had not altered their energy intake. Discussion: The results of this pilot study indicate that exergaming may offer an alternative to traditional exercise for preventing the retention of gestational weight gain and reducing associated health risks, whilst also maintaining lean mass and bone mineral content

Two weeks of watermelon juice supplementation improves nitric oxide bioavailability but not endurance exercise performance in humans

This is the author accepted manuscript. The final version is available from the publisher via the DOI in this record.This study tested the hypothesis that watermelon juice supplementation would improve nitric oxide bioavailability and exercise performance. Eight healthy recreationally-active adult males reported to the laboratory on two occasions for initial testing without dietary supplementation (control condition). Thereafter, participants were randomly assigned, in a cross-over experimental design, to receive 16 days of supplementation with 300 mL·day(-1) of a watermelon juice concentrate, which provided ∼3.4 g l-citrulline·day(-1) and an apple juice concentrate as a placebo. Participants reported to the laboratory on days 14 and 16 of supplementation to assess the effects of the interventions on blood pressure, plasma [l-citrulline], plasma [l-arginine], plasma [nitrite], muscle oxygenation and time-to-exhaustion during severe-intensity exercise. Compared to control and placebo, plasma [l-citrulline] (29 ± 4, 22 ± 6 and 101 ± 23 μM), [l-arginine] (74 ± 9, 67 ± 13 and 116 ± 9 μM) and [nitrite] (102 ± 29, 106 ± 21 and 201 ± 106 nM) were higher after watermelon juice supplementation (P < 0.01). However, systolic blood pressure was higher in the watermelon juice (130 ± 11) and placebo (131 ± 9) conditions compared to the control condition (124 ± 8 mmHg; P < 0.05). The skeletal muscle oxygenation index during moderate-intensity exercise was greater in the watermelon juice condition than the placebo and control conditions (P < 0.05), but time-to-exhaustion during the severe-intensity exercise test (control: 478 ± 80, placebo: 539 ± 108, watermelon juice: 550 ± 143 s) was not significantly different between conditions (P < 0.05). In conclusion, while watermelon juice supplementation increased baseline plasma [nitrite] and improved muscle oxygenation during moderate-intensity exercise, it increased resting blood pressure and did not improve time-to-exhaustion during severe-intensity exercise. These findings do not support the use of watermelon juice supplementation as a nutritional intervention to lower blood pressure or improve endurance exercise performance in healthy adults

Acidification in the Cairngorms and Lochnagar: a palaeoecological assessment

Sensitive lakes in areas of the United Kingdom with moderate to high sulphur deposition have been acidified since the middle of the nineteenth century- (Battarbee et al. 1988). Regions such as Galloway, south west Scotland (eg. Flower and Battarbee 1983, Flower et al. 1987), Wales (eg. Battarbee et al. 1988, Fritz et aL 1990), Cumbria (eg. Battarbee et al 1988, Atkinson and Haworth 1990), and Rannoch Moor in the central Scottish Highlands (eg. Flower et al 1988) have been affected. This study extends the geographical survey of lake acidification to the Caimgorm and Lochnagar regions of north east Scotland (Figure 1). The Caimgorms and Lochnagar are areas of considerable conservation value, forming the largest single area of land over 1000 m in the UK. The Caimgorm mountain plateau is a National Nature Reserve, noted for its alpine flora and fauna, whilst the Lochnagar range is a Scottish Wildlife Trust reserve. A secondary- aim of the study was to evaluate the 11land-use 11 hypothesis (eg. Rosenqvist 1977, 1978, 1981) as a mechanism for lake acidification by examining high altitude sites with no active land-management. Sites selected are all remote, lie above the tree line and have undisturbed catchments. Lochnagar and the Caimgorms are situated on sensitive granite geology (Kinniburgh and Edmunds 1986, Wells et al. 1986) in an area of moderate acid deposition (c. 0.95 g S yr-1 ). It can be predicted that sensitive lakes in this area (those having Ca2 + values of <60 μeq i-1 ) will have acidified (Battarbee 1989)

Sources of uncertainty in future projections of the carbon cycle

This is the final version of the article. Available from the publisher via the DOI in this record.The inclusion of carbon cycle processes within CMIP5 Earth System Models provides the opportunity to explore the relative importance of differences in scenario and climate model representation to future land and ocean carbon fluxes. A two-way ANOVA approach was used to quantify the variability owing to differences between scenarios and between climate models at different lead times. For global ocean carbon fluxes, the variance attributed to differences between Representative Concentration Pathway scenarios exceeds the variance attributed to differences between climate models by around 2025, completely dominating by 2100. This contrasts with global land carbon fluxes, where the variance attributed to differences between climate models continues to dominate beyond 2100. This suggests that modelled processes that determine ocean fluxes are currently better constrained than those of land fluxes, thus we can be more confident in linking different future socio-economic pathways to consequences of ocean carbon uptake than for land carbon uptake. The apparent agreement in atmosphere-ocean carbon fluxes, globally, masks strong climate model differences at a regional level. The North Atlantic and Southern Ocean are key regions, where differences in modelled processes represent an important source of variability in projected regional fluxesMOHC authors were supported by the Joint DECC / Defra Met Office Hadley Centre Cli- mate Programme (GA01101). SY was supported by the Hong Kong Polytechnic University grant “Bayesian Modelling for Quantifying Uncertainty in Climate Predictions” (1-ZV9Z). We acknowl- edge use of R software package (R Core Team 2013). We acknowledge the World Climate Re- search Programme’s Working Group on Coupled Modelling, which is responsible for CMIP and we thank the climate modelling groups for providing their GCM output (listed in Table 1). Support of this dataset was provided by the Office of Science, U.S. Department of Energy