Different current intensities of anodal transcranial direct current stimulation do not differentially modulate motor cortex plasticity

Transcranial direct current stimulation (tDCS) is a noninvasive technique that modulates the excitability of neurons within the motor cortex (M1). Although the aftereffects of anodal tDCS on modulating cortical excitability have been described, there is limited data describing the outcomes of different tDCS intensities on intracortical circuits. To further elucidate the mechanisms underlying the aftereffects of M1 excitability following anodal tDCS, we used transcranial magnetic stimulation (TMS) to examine the effect of different intensities on cortical excitability and short-interval intracortical inhibition (SICI). Using a randomized, counterbalanced, crossover design, with a one-week wash-out period, 14 participants (6 females and 8 males, 22–45 years) were exposed to 10 minutes of anodal tDCS at 0.8, 1.0, and 1.2 mA. TMS was used to measure M1 excitability and SICI of the contralateral wrist extensor muscle at baseline, immediately after and 15 and 30 minutes following cessation of anodal tDCS. Cortical excitability increased, whilst SICI was reduced at all time points following anodal tDCS. Interestingly, there were no differences between the three intensities of anodal tDCS on modulating cortical excitability or SICI. These results suggest that the aftereffect of anodal tDCS on facilitating cortical excitability is due to the modulation of synaptic mechanisms associated with long-term potentiation and is not influenced by different tDCS intensities.

The effect of Mn-rich precipitates on the strength of AZ31 extrudates

The commercial magnesium alloy AZ31 has been subjected to a range of solution treatment regimes. These have then been extruded and their microstructure, texture, and precipitate populations characterized along with their mechanical properties. During the solution treatment, Mn-enriched particles develop and these remain largely unchanged throughout subsequent processing steps. A direct link between grain size and texture has been found, with coarser-grained specimens showing sharper textures. VPSC modeling has been used to quantify the effect of texture on the tensile yield strength, and it has been found that sharper textures have larger tensile yield strengths. Since coarser grain sizes have reduced Hall–Petch hardening, but have an additional texture-strengthening component, a region on the Hall–Petch plot for tension has been identified in which there is an insensitivity of strength to grain size. This has been quantitatively modeled and a texture-modified Hall–Petch plot for tension has been developed. The Mn-rich particles have also been shown to provide precipitate strengthening to the alloy of up to 40 MPa. The compressive behavior was clearer, with the compressive yield strength being directly correlated to grain size and unaffected by texture or precipitation hardening.

Mediated and direct effects of general control beliefs on obsessive compulsive symptoms

Although control-related cognitions have often been implicated in discussions of obsessive compulsive disorder (OCD), empirical investigations of the relationship between control constructs and OCD symptoms have been relatively limited. This article investigated the hypothesis that OCD symptoms may be linked with a higher desire for control (DC), but a lower sense of control (SC) over the self and environment, leading to motivation for compulsive symptoms. It also investigated whether this effect was direct, or mediated through other OCD-related cognitions. This hypothesis was investigated in a nonclinical population, using path analyses controlling for depression. It was found that higher levels of DC and lower levels of SC were associated with higher levels of OCD-related beliefs, and with symptoms via higher OCD-related beliefs. SC was also directly linked with higher OCD symptoms. Control beliefs regarding both the internal (emotions) and external (threat) environment were related to OCD symptoms. Implications for therapy and research are discussed.

Design and analysis of an antenna for batteryless transcranial direct current stimulation devices

The purpose of this study is to design a low-cost planar Archimedean dipole antenna for batteryless transcranial direct current stimulation devices. The antenna parameters including resonance frequency, radiation efficiency, radiation pattern, and gain are simulated using finite difference time domain based electromagnetic simulation software XFdtd. The proposed antenna is simulated with low-cost FR4 PCB substrate of thickness of 1.6 mm. The antenna is designed with half wavelength of resonant frequency and fed with a matching line. The target frequency band is the industrial, scientific and medical (ISM) band of 915 MHz which is in the simulated band width of 31 MHz (903-934MHz). Moreover, since the bio-effect of specific absorption rate by radio frequency electromagnetic wave for power harvesting is an important concern, we try to find out the safety limit. Thus a quantitative analysis of distributions of electric field and power absorption in anatomical human head model by the far field radio frequency energy received by our designed antenna has been presented.

A longitudinal study of the effect of psychosocial factors on exclusive breastfeeding duration

Objective
to examine the effect of psychosocial factors on exclusive breastfeeding duration to six months postpartum

Design
longitudinal, prospective questionnaire based study.

Setting
participants were recruited from a publically funded antenatal clinic located in the western metropolitan region of Melbourne, Victoria, Australia and asked to complete questionnaires at three time points; 32 weeks pregnancy, two months postpartum and six months postpartum.

Participants
the participants were 125 pregnant women aged 22–44 years.

Measurements and findings
psychosocial variables such as breastfeeding self-efficacy, body attitude, psychological adjustment, attitude towards pregnancy, intention, confidence and motivation to exclusively breastfeed and importance of exclusive breastfeeding were assessed using a range of psychometrically validated tools. Exclusive breastfeeding behaviour up to six months postpartum was also measured. At 32 weeks gestation a woman׳s confidence to achieve exclusive breastfeeding was a direct predictor of exclusive breastfeeding duration to six months postpartum. At two months postpartum, psychological adjustment and breastfeeding self-efficacy were predictive of exclusive breastfeeding duration. Finally, at six months postpartum, psychological adjustment, breastfeeding self-efficacy, confidence to maintain and feeling fat were directly predictive of exclusive breastfeeding duration.

Urban surface temperature behaviour and heat island effect in a tropical planned city

 Putrajaya is a model city planned with concepts of a "city in the garden" and an "intelligent city" in the tropics. This study presents the behaviour of the surface temperature and the heat island effect of Putrajaya. Findings show that heat island intensity is 2 °C on average at nighttime and negligible at daytime. But high surface temperature values were recorded at the main boulevard due to direct solar radiation incident, street orientation in the direction of northeast and southwest and low building height-to-street width ratio. Buildings facing each other had cooling effect on surfaces during the morning and evening hours; conversely, they had a warming effect at noon. Clustered trees along the street are effective in reducing the surface temperature compared to scattered and isolated trees. Surface temperature of built up areas was highest at noon, while walls and sidewalks facing northwest were hottest later in the day. Walls and sidewalks that face northwest were warmer than those that face southeast. The surface temperatures of the horizontal street surfaces and of vertical façades are at acceptable levels relative to the surface temperature of similar surfaces in mature cities in subtropical, temperate and Mediterranean climates. © 2014 Springer-Verlag Wien.

Effect of heat on firefighters' work performance and physiology

Wildland firefighters often perform their duties under both hot and mild ambient temperatures. However, the direct impact of different ambient temperatures on firefighters' work performance has not been quantified. This study compared firefighters' work performance and physiology during simulated wildland firefighting work in hot (HOT; 32°C, 43% RH) and temperate (CON; 19°C, 56% RH) conditions. Firefighters (n=38), matched and allocated to either the CON (n=18) or HOT (n=20) condition, performed simulated self-paced wildland fire suppression tasks (e.g., hose rolling/dragging, raking) in firefighting clothing for six hours, separated by dedicated rest breaks. Task repetitions were counted (and converted to distance or area). Core temperature (Tc), skin temperature (Tsk), and heart rate were recorded continuously throughout the protocol. Urine output was measured before and during the protocol, and urine specific gravity (USG) analysed, to estimate hydration. Ad libitum fluid intake was also recorded. There were no differences in overall work output between conditions for any physical task. Heart rate was higher in the HOT (55±2% HRmax) compared to the CON condition (51±2% HRmax) for the rest periods between bouts, and for the static hose hold task (69±3% HRmax versus 65±3% HRmax). Tc and Tsk were 0.3±0.1°C and 3.1±0.2°C higher in the HOT compared to the CON trial. Both pre- and within- shift fluid intake were increased two-fold in the heat, and participants in the heat recorded lower USG results than their CON counterparts. There was no difference between the CON and HOT conditions in terms of their work performance, and firefighters in both experimental groups increased their work output over the course of the simulated shift. Though significantly hotter, participants in the heat also managed to avoid excessive cardiovascular and thermal strain, likely aided by the frequent rest breaks in the protocol, and through doubling their fluid intake. Therefore, it can be concluded that wildland firefighters are able to safely and efficiently perform their duties under hot conditions, at least over six hours.

Foreign direct investment and economic growth: A real relationship or wishful thinking?

Several theories have been advanced on the beneficial effect of foreign direct investment (FDI) on economic growth. However, mixed empirical findings have resulted in a long-standing debate. This study explores the global FDI-growth relationship through an 'informed' econometric analysis predicated on substantial guidance obtained from a detailed investigation of 880 estimates reported in 108 published studies. With model uncertainties alleviated and the core specification benchmarked against the aforementioned assessment, our econometric analysis, utilising a global sample of 140 countries in the period 1970 to 2009, conclusively documents that FDI positively affects economic growth. Moreover, we find that this association holds globally as strongly as in the developing world. Further, it is regional variation rather than within-country variation, and contemporaneous FDI rather than past FDI, which matters for growth. Finally, appropriate absorptive capacity indicators for positive growth are identified to be trade openness and financial development rather than schooling.

Effect of cooling rate on phase transformations in a high-strength low-alloy steel studied from the liquid phase

The phase transformation and precipitation in a high-strength low-alloy steel have been studied over a large range of cooling rates, and a continuous cooling transformation (CCT) diagram has been produced. These experiments are unique because the measurements were made from samples cooled directly from the melt, rather than in homogenized and re-heated billets. The purpose of this experimental design was to examine conditions pertinent to direct strip casting. At the highest cooling rates which simulate strip casting, the microstructure was fully bainitic with small regions of pearlite. At lower cooling rates, the fraction of polygonal ferrite increased and the pearlite regions became larger. The CCT diagram and the microstructural analysis showed that the precipitation of NbC is suppressed at high cooling rates, and is likely to be incomplete at intermediate cooling rates.

Potential degrading effect of sodium hypochlorite on exhibits containing DNA

The use of a sodium hypochlorite solution as a cleaning reagent is common practice among many laboratories for contamination minimisation purposes. Whilst its effectiveness in the decontamination of tools and surfaces has been verified at specific concentrations, it has not yet been established whether any residual sodium hypochlorite potentially remaining on tools/surfaces following cleaning has a detrimental effect if direct contact is made with an exhibit containing DNA. To investigate the effect of residual hypochlorite, surfaces were treated with 10% hypochlorite (air-dried or wiped dry), 1% hypochlorite (air-dried or wiped dry), or 1% hypochlorite (wiped dry) followed by the application of water (wiped dry). Treated surfaces came into contact with surfaces carrying 200. ng of DNA within 100. μL, or 20. ng within 20. μL. To observe the potential degrading effects of sodium hypochlorite, the quantity and quality of DNA within DNA deposits following contact with treated and untreated surfaces were compared. Overall, no degrading effect on DNA quantity/quality was observed, with the exception of DNA deposits that came into contact with surfaces treated with 10% hypochlorite and air-dried. It is therefore recommended that surfaces cleaned with high concentrations of hypochlorite be wiped dry or rinsed with an appropriate agent (water) following application.