Wide range and tunable linear TMR sensor using two exchange pinned electrodes

A magnetic tunnel junction sensor is proposed, with both the detection and the reference layers pinned by IrMn. Using the differences in the blocking temperatures of the IrMn films with different thicknesses, crossed anisotropies can be induced between the detection and the reference electrodes. The pinning of the sensing electrode ensures a linear and reversible output. It also allows tuning both the sensitivity and the linear range of the sensor. The authors show that the sensitivity varies linearly with the ferromagnetic thickness of the detection electrode. It is demonstrated that an increased thickness leads to a rise of sensitivity and a reduction of the operating range

The Sum of lts Parts-Effects of Gastric Distention, Nutrient Content and Sensory Stimulation on Brain Activation

During food consumption the brain integrates multiple interrelated neural and hormonal signals involved in the regulation of food intake. Factors influencing the decision to stop eating include the foods' sensory properties, macronutrient content, and volume, which in turn affect gastric distention and appetite hormone responses. So far, the contributions of gastric distention and oral stimulation by food on brain activation have not been studied. The primary objective of this study was to assess the effect of gastric distention with an intra-gastric load and the additional effect of oral stimulation on brain activity after food administration. Our secondary objective was to study the correlations between hormone responses and appetite-related ratings and brain activation. Fourteen men completed three functional magnetic resonance imaging sessions during which they either received a naso-gastric infusion of water (stomach distention), naso-gastric infusion of chocolate milk (stomach distention + nutrients), or ingested chocolate-milk (stomach distention + nutrients + oral exposure). Appetite ratings and blood parameters were measured at several time points. During gastric infusion, brain activation was observed in the midbrain, amygdala, hypothalamus, and hippocampus for both chocolate milk and water, i.e., irrespective of nutrient content. The thalamus, amygdala, putamen and precuneus were activated more after ingestion than after gastric infusion of chocolate milk, whereas infusion evoked greater activation in the hippocampus and anterior cingulate. Moreover, areas involved in gustation and reward were activated more after oral stimulation. Only insulin responses following naso-gastric infusion of chocolate milk correlated with brain activation, namely in the putamen and insula. In conclusion, we show that normal (oral) food ingestion evokes greater activation than gastric infusion in stomach distention and food intake-related brain areas. This provides neural evidence for the importance of sensory stimulation in the process of satiation

Spatial and seasonal dynamics of water physical-chemical parameters of an Argentine Patagonian basin

Se analizaron las principales características físicas, químicas y biológicas de los cuerpos de agua de la cuenca del río Senguer para establecer sus variaciones espaciales y estacionales. En cada estación del año se midió la concentración de clorofila a (cl a), sedimentos en suspensión (SST), salinidad (S), pH, oxígeno disuelto (OD) y profundidad de disco de Secchi (en lagos). Los parámetros físico-químicos de los ríos y lagos de la cuenca varían espacial y estacionalmente, relacionado con las condiciones climáticas, litológicas y de cobertura y uso del suelo. Entre los dos extremos de la cuenca el lago Fontana (FO, en la cordillera de los Andes) y el lago Musters (MU, en la meseta patagónica) observamos importantes diferencias en OD (FO = 9,4 ± 0,7 mg L-1; Mu2 = 8,9 ± 3,8 mg L-1), SST (FO = 0.4± 0.2 mg L-1; Mu2 = 4,3 ± 2,6 mg L-1), S (FO = 14 ± 1 1 mg L-1; Mu2 = 278 ± 9 mg L-1) y Cl a (FO = 0,4 ± 0,6 μg L-1; Mu2 = 4,1 ± 6,2 mg L-1).Centro de Investigaciones Geológica

Spatial and seasonal dynamics of water physical-chemical parameters of an Argentine Patagonian basin

Se analizaron las principales características físicas, químicas y biológicas de los cuerpos de agua de la cuenca del río Senguer para establecer sus variaciones espaciales y estacionales. En cada estación del año se midió la concentración de clorofila a (cl a), sedimentos en suspensión (SST), salinidad (S), pH, oxígeno disuelto (OD) y profundidad de disco de Secchi (en lagos). Los parámetros físico-químicos de los ríos y lagos de la cuenca varían espacial y estacionalmente, relacionado con las condiciones climáticas, litológicas y de cobertura y uso del suelo. Entre los dos extremos de la cuenca el lago Fontana (FO, en la cordillera de los Andes) y el lago Musters (MU, en la meseta patagónica) observamos importantes diferencias en OD (FO = 9,4 ± 0,7 mg L-1; Mu2 = 8,9 ± 3,8 mg L-1), SST (FO = 0.4± 0.2 mg L-1; Mu2 = 4,3 ± 2,6 mg L-1), S (FO = 14 ± 1 1 mg L-1; Mu2 = 278 ± 9 mg L-1) y Cl a (FO = 0,4 ± 0,6 μg L-1; Mu2 = 4,1 ± 6,2 mg L-1).Centro de Investigaciones Geológica

Interactions between metabolic, reward and cognitive processes in appetite control:Implications for novel weight management therapies

Traditional models of appetite control have emphasised the role of parallel homeostatic and hedonic systems, but more recently the distinction between independent homeostatic and hedonic systems has been abandoned in favour of a framework that emphasises the cross talk between the neurochemical substrates of the two systems. In addition, evidence has emerged more recently, that higher level cognitive functions such as learning, memory and attention play an important role in everyday appetite control and that homeostatic signals also play a role in cognition. Here, we review this evidence and present a comprehensive model of the control of appetite that integrates cognitive, homeostatic and reward mechanisms. We discuss the implications of this model for understanding the factors that may contribute to disordered patterns of eating and suggest opportunities for developing more effective treatment approaches for eating disorders and weight management

Can we predict real-time fMRI neurofeedback learning success from pretraining brain activity?

Neurofeedback training has been shown to influence behavior in healthy participants as well as to alleviate clinical symptoms in neurological, psychosomatic, and psychiatric patient populations. However, many real-time fMRI neurofeedback studies report large inter-individual differences in learning success. The factors that cause this vast variability between participants remain unknown and their identification could enhance treatment success. Thus, here we employed a meta-analytic approach including data from 24 different neurofeedback studies with a total of 401 participants, including 140 patients, to determine whether levels of activity in target brain regions during pretraining functional localizer or no-feedback runs (i.e., self-regulation in the absence of neurofeedback) could predict neurofeedback learning success. We observed a slightly positive correlation between pretraining activity levels during a functional localizer run and neurofeedback learning success, but we were not able to identify common brain-based success predictors across our diverse cohort of studies. Therefore, advances need to be made in finding robust models and measures of general neurofeedback learning, and in increasing the current study database to allow for investigating further factors that might influence neurofeedback learning

Neural correlates of top-down guidance of attention to food: an fMRI study

We investigated the neural correlates of working memory guided attentional selection of food versus non-food stimuli in young women. Participants were thirty-two women, aged 20.6y (± 0.5) who were presented with a cue (food or non-food item) to hold in working memory. Subsequently, they had to search for a target in a 2-item display where target and distractor stimuli were each flanked by a picture of a food or a non-food item. The behavioural data showed that attention is particularly efficiently drawn to food stimuli when thinking about food. Using fMRI, we found that holding a non-food versus food stimulus in working memory was associated with increased activity in occipital gyrus, fusiform, inferior and superior frontal gyrus. In the posterior cingulum, retrosplenial cortex, a food item that re-appeared in the search array when it was held in memory led to a reduced response, compared to when it did not re-appear. The reverse effect was found for non-food stimuli. The extent of the reappearance effect correlated with the attentional capture of food as measured behaviourally. In conclusion, these results suggest that holding food in mind may bias attention because thinking of food facilitated neuronal responses to sensory input related to food stimuli and because holding food-related information in mind is less taxing on memory

The effect of intranasal insulin on appetite and mood in women with and without obesity: an experimental medicine study

Background/Objectives Intranasal (IN) administration of insulin decreases appetite in humans, but the underlying mechanisms are unclear, and it is unknown whether IN insulin affects the food intake of women with obesity. Subjects/Methods In a double-blind, placebo-controlled, crossover design, participants (35 lean women and 17 women with obesity) were randomized to receive 160 IU/1.6 mL of IN insulin or placebo in a counterbalanced order in the post prandial state. The effects of IN insulin on cookie intake, appetite, mood, food reward, cognition and neural activity were assessed. Results IN insulin in the post prandial state reduced cookie intake, appetite and food reward relative to placebo and these effects were more pronounced for women with obesity compared with lean women. IN insulin also improved mood in women with obesity. In both BMI groups, IN insulin increased neural activity in the insula when viewing food pictures. IN insulin did not affect cognitive function. Conclusions These results suggest that IN insulin decreases palatable food intake when satiated by reducing food reward and that women with obesity may be more sensitive to this effect than lean women. Further investigation of the therapeutic potential of IN insulin for weight management in women with obesity is warranted