OBJECTIVES/SPECIFIC AIMS: The study aimed to determine the effects of bilateral frontal active transcranial direct current stimulation (tDCS) at 2 mA for 12 minute Versus sham stimulation on functional connectivity of the working memory network during an fMRI N-Back task. METHODS/STUDY POPULATION: Stimulation was delivered over bilateral frontal dorsolateral prefrontal cortex via and MRI-compatible tDCS device during an fMRI working memory task in healthy older adults in a within-subject design. RESULTS/ANTICIPATED RESULTS: Active stimulation compared with sham resulted in significant increases in functional connectivity in working memory related brain regions during the N-Back task. DISCUSSION/SIGNIFICANCE OF IMPACT: Older adults typically have reduced functional connectivity compared with young adults. Our findings demonstrate that a single session of tDCS can increase functional connectivity of the working memory network in older adults. Based on this mechanism of effect, tDCS may serve as an adjunctive method for interventions aiming to enhance cognitive processes in older adults.

Linear relationships between the mass of sediment present in a cryoconite hole and the hole area are described for a range of glacier and ice-sheet surfaces. The strong relationships found indicate that some mechanism regulates the thickness of the layer of sediment occupying the ‘floor’ of the hole. We find that this regulation process responds immediately to the addition of new debris to a hole and infer that it is caused by lateral thermal conduction from the debris to the hole wall. This causes hole widening by melt, and a redistribution of the debris within then takes place, usually resulting in 0.04–0.20 gcm−2 of debris in a layer of single cryoconite grains. The thinning of the debris layer during hole widening also reduces self-shading and thus maximizes the exposure of cryoconite to solar radiation. We explore the implications of the hole widening for biological production. Net photosynthesis (CO2 fixation) is shown to be favoured by thin debris layers, whilst net heterotrophy (CO2 respiration) occurs when debris layers are in excess of 2–4 mm. We conclude that the carbon balance of cryoconite holes is sensitive to the thickness of the debris and that the thermodynamic equilibration of the debris thickness helps the ecosystem to maximize primary production during the summer.

Photosynthesis by microbes on the surfaces of glaciers and ice sheets has the potential to fix carbon, alter the albedo of ice surfaces via the production of organic matter and so enhance ice melt. It could also be important for supplying labile organic matter and nutrients to in situ and downstream ecosystems. This study compares in situ 24 hour incubation methods for measuring rates of gross photosynthesis, respiration and net community production (NCP) in cryoconite holes on three Svalbard valley glaciers. Rates of gross photosynthesis and respiration measured by the ΔCO2 method were closely balanced, resulting in rates of NCP close to the detection limit (mean of –1.3 μg C g−1 d–1) consistent with previous measurements in Arctic cryoconite holes. This suggests that organic matter within cryoconite holes may be derived largely from allochthonous sources. The molar ratio of ΔO2 to ΔCO2 in incubations gave mean respiratory and photosynthetic quotients of 0.80 ± 0.17 (1 × SD) and 1.24 ± 0.20 (1 × SD), respectively. The 14C method typically underestimated rates of gross photosynthesis (ΔCO2 method) by more than one order of magnitude and measured a rate closer to NCP.

Microbially mediated carbon fluxes on the surface of the Greenland ice sheet (GrIS) were recently quantified by Hodson and others (2010) using measurements of the surface coverage of debris (cryoconite) and rates of biological production associated with debris near the ice-sheet margin. We present updated models that do not assume the same spatial uniformity in key parameters employed by Hodson and others (2010) because they make use of biomass distribution and biological production data from a 79 km transect of the GrIS. Further, the models presented here also include for the first time biomass associated with both cryoconite holes and surficial algae. The predicted annual carbon flux for a small (1600 km2) section of ice surrounding the field transect is about four times that estimated using spatially uniform biomass and production in this area. When surficial algae are included, the model predicts about 11 times more carbon fixation via photosynthesis per year than the cryoconite-only models. We therefore suggest that supraglacial carbon fluxes from the GrIS have previously been underestimated by more than an order of magnitude and that the hitherto overlooked surficial algal ecosystem can be the most crucial contributor. The GrIS is shown to be in a relatively stable state of net autotrophy according to our model and so a strong link between bare-ice area and total carbon fluxes is evident. The implication is a biomass feedback to surface albedo and enhanced ablation as a result. Climate predictions for the year 2100 show that greater carbon fixation could also result from climate warming.

Streptococcus pneumoniae (Spn) is a leading cause of community-acquired pneumonia (CAP), yet existing diagnostic tools remain inadequate. We aimed to evaluate laboratory and radiological methods for detecting pneumococcal aetiology in CAP patients and to estimate Spn prevalence in this group. All-aged patients hospitalized with clinically defined CAP in northern Togo were enrolled during 2010–2013. Latent class analysis pooled results of semi-automated blood culture (SABC), whole blood lytA real-time polymerase chain reaction (rt-PCR), serum C-reactive protein (CRP), and chest radiography (CXR) and categorized patients as likely pneumococcal or non-pneumococcal CAP. We enrolled 1684 patients; 1501 had results for all tests. CXR, SABC, lytA rt-PCR and CRP >71·2 mg/l had sensitivities of 94% [95% confidence interval (CI) 87–100], 13% (95% CI 10–16), 17% (95% CI 14–21) and 78% (95% CI 75–80), and specificities of 88% (95% CI 84–93), 100% (95% CI 99–100), 97% (95% CI 96–99) and 77% (95% CI 75–79), respectively. Pneumococcal attributable proportion was 34% (95% CI 32–37), increasing with age and in men. We estimated that Spn caused one third of CAP. Whole blood lytA rt-PCR was more sensitive than SABC; both had low sensitivity and high specificity. Conversely CXR was highly sensitive and reasonably specific; it could be a useful tool for epidemiological studies aiming to define Spn pneumonia incidence across all ages.

The healthy Nordic diet has been previously shown to have health beneficial effects among subjects at risk of CVD. However, the extent of food changes needed to achieve these effects is less explored. The aim of the present study was to investigate the effects of exchanging a few commercially available, regularly consumed key food items (e.g. spread on bread, fat for cooking, cheese, bread and cereals) with improved fat quality on total cholesterol, LDL-cholesterol and inflammatory markers in a double-blind randomised, controlled trial. In total, 115 moderately hypercholesterolaemic, non-statin-treated adults (25–70 years) were randomly assigned to an experimental diet group (Ex-diet group) or control diet group (C-diet group) for 8 weeks with commercially available food items with different fatty acid composition (replacing SFA with mostly n-6 PUFA). In the Ex-diet group, serum total cholesterol (P<0·001) and LDL-cholesterol (P<0·001) were reduced after 8 weeks, compared with the C-diet group. The difference in change between the two groups at the end of the study was −9 and −11 % in total cholesterol and LDL-cholesterol, respectively. No difference in change in plasma levels of inflammatory markers (high-sensitive C-reactive protein, IL-6, soluble TNF receptor 1 and interferon-γ) was observed between the groups. In conclusion, exchanging a few regularly consumed food items with improved fat quality reduces total cholesterol, with no negative effect on levels of inflammatory markers. This shows that an exchange of a few commercially available food items was easy and manageable and led to clinically relevant cholesterol reduction, potentially affecting future CVD risk.

The tetracyclines (TTC) and sulfonamides are among the most common residues found in bulk raw milk samples. Detection of drug residues in bulk milk (BM) tankers demonstrates that the product is not suitable for human consumption. Discarding BM with residue-contaminated milk is a waste of a valuable commodity, and a repurposing for consumption at calf ranches is a way to recapture some value. However, if calves consuming milk with drug residues are slaughtered for veal, their meat could contain drug residues. The objective of this review is to provide a residue avoidance strategy for TTC and sulfonamide residues in veal. To determine the pharmacokinetic properties of each drug a structured review of the literature was performed and the study inclusion criteria were that the publication used dairy breed calves, with body weight <330 kg or <6 months of age. The most pertinent parameters were determined to be plasma, tissue elimination half-lives, and systemic bioavailability. The results of this review were integrated with milk and tissue testing levels of quantification and tissue tolerances to formulate a recommended withdrawal interval for calves ingesting this milk. The suggested withdrawal interval of 20 days will ensure that no veal calves will test positive for residues from being fed this milk.

Vigabatrin (ɣ-vinyl GABA; GVG), an irreversible inhibitor of GABA-transaminase, at a daily dose of 2-4 g, and a placebo were each administered orally for 4 months to 14 patients with cerebellar ataxia (9 with Friedreich's ataxia, 5 with olivopontocerebellar atrophy), in a double-blind, placebo-controlled crossover study. For the group as a whole, there was no significant difference between the GVG and placebo periods in any of the parameters of cerebellar symptomatology measured. Individually, one patient showed some improvement after 3 months of treatment with 2 g/day GVG. Tolerance to 4 g/day GVG was poor, whereas 2 g/day was well tolerated. The results suggest that agents which increase central GABA concentrations are not likely to be of benefit to patients with Friedreich's ataxia or olivopontocerebellar atrophy.

Vitamins B2 and B6 are cofactors in the kynurenine pathway. Many of the kynurenines are neuroactive compounds with immunomodulatory effects. In the present study, we aimed to investigate plasma concentrations of vitamins B2 and B6 as determinants of kynurenines and two markers of interferon-γ-mediated immune activation (kynurenine:tryptophan ratio (KTR) and neopterin). We measured the concentrations of vitamins B2 and B6 vitamers, neopterin, tryptophan and six kynurenines (i.e. kynurenine, anthranilic acid, kynurenic acid, 3-hydroxykynurenine, 3-hydroxyanthranilic acid and xanthurenic acid) in plasma from 7051 individuals. Dietary intake of vitamins B2 and B6 was assessed using a validated FFQ. Associations were investigated using partial Spearman's correlations, generalised additive models, and segmented or multiple linear regression. The B2 vitamer, riboflavin, was positively associated with 3-hydroxyanthranilic acid and xanthurenic acid, with correlation coefficients, as obtained by segmented regression, of 0·20 (95 % CI 0·16, 0·23) and 0·24 (95 % CI 0·19, 0·28), at riboflavin concentrations below the median value (13·0 nmol/l). The vitamin B6 vitamer, pyridoxal 5′-phosphate (PLP), was positively associated with most kynurenines at PLP concentrations < 39·3–47·0 nmol/l, and inversely associated with 3-hydroxykynurenine with the association being more prominent at PLP concentrations < 18·9 nmol/l. Riboflavin and PLP were associated with xanthurenic acid only at relatively low, but normal concentrations of both vitamers. Lastly, PLP was negatively correlated with neopterin and KTR. These results demonstrate the significant and complex determination of kynurenine metabolism by vitamin status. Future studies on B-vitamins and kynurenines in relation to chronic diseases should therefore integrate data on relevant biomarkers related to B-vitamins status and tryptophan metabolism.

A combination of high folate with low vitamin B12 plasma status has been associated with cognitive impairment in a population exposed to mandatory folic acid fortification. The objective of the present study was to examine the interactions between plasma concentrations of folate and vitamin B12 markers in relation to cognitive performance in Norwegian elderly who were unexposed to mandatory or voluntary folic acid fortification. Cognitive performance was assessed by six cognitive tests in 2203 individuals aged 72–74 years. A combined score was calculated using principal component analysis. The associations of folate concentrations, vitamin B12 markers (total vitamin B12, holotranscobalamin (holoTC) and methylmalonic acid (MMA)) and their interactions in relation to cognitive performance were evaluated by quantile regression and least-squares regression, adjusted for sex, education, apo-ɛ4 genotype, history of CVD/hypertension and creatinine. Cross-sectional analyses revealed an interaction (P= 0·009) between plasma concentrations of folate and vitamin B12 in relation to cognitive performance. Plasma vitamin B12 concentrations in the lowest quartile ( < 274 pmol/l) combined with plasma folate concentrations in the highest quartile (>18·5 nmol/l) were associated with a reduced risk of cognitive impairment compared with plasma concentrations in the middle quartiles of both vitamins (OR 0·22, 95 % CI 0·05, 0·92). The interaction between folate and holoTC or MMA in relation to cognitive performance was not significant. In conclusion, this large study population unexposed to mandatory folic acid fortification showed that plasma folate, but not plasma vitamin B12, was associated with cognitive performance. Among the elderly participants with vitamin B12 concentrations in the lower range, the association between plasma folate and cognitive performance was strongest.

Multiwalled carbon nanotube (MWCNT)/Nylon-6 nanohybrids were prepared by in situ polymerization under microwave irradiation. The effect of time and power of irradiation on the surface conductivity of the nanohybrid was studied. It was observed that the resistivity increases with irradiation time at low microwave power (200W). On the other hand, at high power (600W) an opposite behavior was observed. And at intermediate power (400W) the resistivity was independent of the irradiation time. Resistivity values range from 102 to 101 Ω/sq. This behavior was associated with the polymer nanocoating covering the surface of the carbon nanotubes.

The effect of four temperatures (18, 20, 25 and 30°C) on pupa development and sexual maturity of Anastrepha obliqua adults was investigated under laboratory conditions. The results showed that the duration of the pupal stage decreased with an increase in temperature (29, 25, 13 and 12 days, respectively), and maintaining the pupae at 18°C and 20°C results in a low percentage of pupation, pupa weight loss and lesser flying ability. However, it significantly favored sexual behavior, a higher proportion of sexual calls and matings. While enhanced pupa development was observed at a temperature of 30°C, adults had low sexual efficiency, as well as a lower proportion of calls and matings. Gas chromatography-mass spectrometry (GC-MS) analysis of male volatiles showed that the amount of (Z,E)-α-farnesene did not vary among males from pupae reared at different temperatures; however, less (E,E)-α-farnesene was emitted by males obtain from pupa reared at 30°C. Male flies kept at 30°C during their larval stage had more (Z)-3-nonenol and, also, an unknown compound was detected. The fecundity of the females was higher at low temperatures. Regarding fertility, no significant differences were found between temperatures. The optimal temperature on pupa development was 25°C when males displayed ideal attributes for rearing purposes.

Equipment for the sterilization of air by heat with capacities of 140 l./min., and 1700 l./min. respectively is described. An improved method for testing sterility is given.

In the last decade, a declining prevalence of HCV infection has been described in injecting drug users (IDUs) in different countries. This study is the first to assess temporal trends in drug-injecting patterns, HCV infection rates and viral genotype distribution in 770 Brazilian IDUs, recruited by two cross-sectional studies (1994–1997 and 1999–2001). A substantial decline in the prevalence of HCV infection was found over the years (75% in 1994 vs. 20·6% in 2001, P<0·001) that may be a consequence of the significant reduction in the overall frequencies of drug injection and needle-sharing, as well as the participation of IDUs in initiatives aimed at reducing drug-related harm. No trend was found in terms of viral genotype distribution. Despite the favourable scenario, preventive measures must be maintained, especially in vulnerable subgroups such as young or new injectors, where risky behaviours through direct and indirect sharing practices remain common.

We have previously shown that adult female rats exposed to intra-uterine malnutrition were normophagic, although obese and resistant to insulin-induced hypophagia. The present study aimed at examining aspects of another important catabolic component of energy homeostasis control, the hypothalamic serotonergic function, which inhibits feeding and stimulates energy expenditure. Pregnant dams were fed ad libitum or were restricted to 50 % of ad libitum intake during the first 2 weeks of pregnancy. Control and restricted 4-month-old progeny were studied. The restricted rats had increased body adiposity with normal daily food intake but failed to respond with hypophagia to an intracerebroventricular injection of serotonin (5-hydroxytryptamine; 5-HT). Stimulation, by food ingestion, of extracellular levels of serotonin in medial hypothalamus microdialysates was more pronounced and lasted longer in the restricted than in the control rats. In the restricted group, hypothalamic levels of 5-HT2C receptor protein tended to be reduced (P = 0·07) while the levels of 5-HT1B receptor and serotonin transporter proteins were significantly elevated (36 and 79 %, respectively). In conclusion, female rats undernourished in utero had normophagic obesity as adults but had an absence of serotonin-induced hypophagia and low hypothalamic levels of the 5-HT2C receptor. Compensatory adaptations for the functional serotonergic impairment were evidenced, such as an enhanced release of serotonin in response to a meal allied to up-regulated hypothalamic 5-HT1B and transporter expression. Whether these compensations will persist in later life warrants further investigation. Moreover, it cannot be ruled out that the serotonergic component of energy expenditure was already impaired, thus contributing to the observed body-fat phenotype.

Blue compact dwarf (BCD) galaxies are low-metallicity objects undergoing violent star formation (Searle & Sargent 1972). We present our ongoing work on integral field spectroscopy (IFS) of the two prototypical BCD galaxies IIZw70 and IZw18 (Papaderos et al. 2002). Two-dimensional spectroscopy allows us to collect simultaneously the spectra of many different regions of an extended object, combining photometry and spectroscopy in the same data set. The great advantage of using IFS for the investigation of galaxies is that it allows us to obtain data on the galaxies' positions, velocity fields and star-forming properties all in one data cube. The observations were taken with the instruments INTEGRAL/WYFFOS at the WHT (ORM, La Palma) and PMAS installed on the 3.5m telescope at the CAHA, covering a spectral range from λ 3600 to 6800 Å. The data are mainly used to study the ionized gas and stellar clusters. Our main goal is to investigate the presence of spatial variations in ionization structure indicators, physical conditions and gaseous metal abundances, in these galaxies (Vílchez & Iglesias-Páramo 1998). We also study the kinematical properties of the ionized gas, as well as systematic variations of ionization structure and physical-chemical parameters as a function of the surface-brightness in Hα emission. Maps of the relevant emission lines are presented.

We present a detailed spectroscopic study of a sample of 34 star-forming dwarf galaxies, ranging from the blue to near-infrared (λ3700Å-1μm) (Kehrig et al. 2006). The metal enrichment in this kind of objects has been operating typically at low metallicity enviroments. The spectra were observed with the 1.52m telescope at La Silla/ESO. We derive fundamental parameters for HII regions and ionizing sources in our star-forming galaxies, as well as gaseous metal abundances. All the spectra include the nebular[SIII]λλ9069,9532Å lines, that are of crucial importance in the derivation of the S/H abundances, and relevant ionization diagnostics. We study the relative hardness of their ionizing sources using the η' parameter (Vílchez & Pagel 1988), and exploring the roles played by metallicity and age. The ionic and total O/H was also derived using direct determinations of the te[OIII]. The mean S/O ratio derived in this work is constant and slightly below the solar (S/O)⊙ value (see fig 1). The data presented here are consistent with the conclusion that S/O remains constant as O/H varies among the sample of HII galaxies. Variations in S/O along the whole O/H abundance range may be present, but the scatter in S/O (due mainly to observational errors) is still large to constrain them. The assumption that the S/O ratio remains constant for all abundances is still an open question and should be explored further (Pérez-Montero et al. 2006).