291 research outputs found

    Effect of Pulsed or Continuous Delivery of Salt on Sensory Perception Over Short Time Intervals

    Get PDF
    Salt in the human diet is a major risk factor for hypertension and many countries have set targets to reduce salt consumption. Technological solutions are being sought to lower the salt content of processed foods without altering their taste. In this study, the approach was to deliver salt solutions in pulses of different concentrations to determine whether a pulsed delivery profile affected sensory perception of salt. Nine different salt profiles were delivered by a Dynataste device and a trained panel assessed their saltiness using time–intensity and single-score sensory techniques. The profile duration (15 s) was designed to match eating conditions and the effects of intensity and duration of the pulses on sensory perception were investigated. Sensory results from the profiles delivered in either water or in a bouillon base were not statistically different. Maximum perceived salt intensities and the area under the time– intensity curves correlated well with the overall perceived saltiness intensity despite the stimulus being delivered as several pulses. The overall saltiness scores for profiles delivering the same overall amount of sodium were statistically not different from one another suggesting that, in this system, pulsed delivery did not enhance salt perception but the overall amount of salt delivered in each profile did affect sensory perception

    Neither a Nitric Oxide Donor Nor Potassium Channel Blockage Inhibit RBC Mechanical Damage Induced by a Roller Pump

    Get PDF
    Red blood cells (RBC) are exposed to various levels of shear stresses when they are exposed to artificial flow environments, such as extracorporeal flow circuits and hemodialysis equipment. This mechanical trauma affects RBC and the resulting effect is determined by the magnitude of shear forces and exposure time. It has been previously demonstrated that nitric oxide (NO) donors and potassium channel blockers could prevent the sub-hemolytic damage to RBC, when they are exposed to 120 Pa shear stress in a Couette shearing system. This study aimed at testing the effectiveness of NO donor sodium nitroprussid (SNP, 10-4 M) and non-specific potassium channel blocker tetraethylammonium (TEA, 10-7 M) in preventing the mechanical damage to RBC in a simple flow system including a roller pump and a glass capillary of 0.12 cm diameter. RBC suspensions were pumped through the capillary by the roller pump at a flow rate that maintains 200 mmHg hydrostatic pressure at the entrance of the capillary. An aliquot of 10 ml of RBC suspension of 0.4 L/L hematocrit was re-circulated through the capillary for 30 minutes. Plasma hemoglobin concentrations were found to be significantly increased (~7 folds compared to control aliquot which was not pumped through the system) and neither SNP nor TEA prevented this hemolysis. Alternatively, RBC deformability assessed by laser diffraction ektacytometry was not altered after 30 min of pumping and both SNP and TEA had no effect on this parameter. The results of this study indicated that, in contrast with the findings in RBC exposed to a well-defined magnitude of shear stress in a Couette shearing system, the mechanical damage induced by a roller pump could not be prevented by NO donor or potassium channel blocker

    Impact of altering proximity on snack food intake in individuals with high and low executive function: study protocol.

    Get PDF
    BACKGROUND: Despite attempts to improve diet at population level, people living in material and social deprivation continue to consume unhealthy diets. Executive function - the ability to regulate behaviour and resist impulses - is weaker in individuals living in deprivation. Dietary interventions that educate and persuade people to reflect on and actively change behaviour may therefore disproportionately benefit individuals who are socioeconomically advantaged and have stronger executive function, thus exacerbating inequalities in health resulting from unhealthy diets. In contrast, manipulating environmental cues, such as how far away a food is placed, does not appeal to reasoned action and is thought to operate largely outside of awareness to influence behaviour. People eat more of a food when it is placed closer to them, an effect seemingly robust to context, food quality and body-weight status. However, previous studies of this 'proximity effect' are limited by small samples consisting mainly of university staff or students, biased towards higher socio-economic position and therefore likely stronger executive function. This study aims to test the hypothesis that placing food further away from a person decreases intake of that food regardless of executive function. METHODS/DESIGN: 156 members of the general public, recruited from low and high socio-economic groups, will be randomised to one of two conditions varying in the proximity of a snack food relative to their position: 20 cm or 70 cm. Participants are told they will be taking part in a relaxation study - and are fully debriefed at the conclusion of the session. The primary outcome is the proportion of participants eating any amount of snack food and the secondary outcome is the mean amount eaten. Executive function is assessed using the Stroop task. DISCUSSION: The proposed study takes a novel step by investigating the effect of proximity on snack food intake in a general population sample consisting of those with high and low executive function, appropriately powered to detect the predicted proximity effect. If this effect occurs irrespective of executive function and socio-economic position, it may have potential to reduce inequalities patterned by socio-economic position if implemented in real-world settings such as shops or restaurants. TRIAL REGISTRATION: Registered with the ISRCTN registry: ISRCTN46995850 on 07 October 2015.This study is supported by the Medical Research Council (MRC) and Sackler Prize, a doctoral training grant awarded to JAH. The study was also partially funded by the Department of Health Policy Research Program (Policy Research Unit in Behavior and Health [PR-UN-0409-10109]).This is the final version of the article. It first appeared from BioMed Central via http://dx.doi.org/10.1186/s12889-016-3184-

    Hemodynamic effects of red blood cell aggregation

    No full text
    25-31The influence of red blood cell (RBC) aggregation on blood flow in vivo has been under debate since early 1900’s, yet a full understanding has still has not been reached. Enhanced RBC aggregation is well known to increase blood viscosity measured in rotational viscometers. However, it has been demonstrated that RBC aggregation may decrease flow resistance in cylindrical tubes, due to the formation of a cell-poor zone near the tube wall which results from the enhanced central accumulation of RBC. There is also extensive discussion regarding the effects of RBC aggregation on in vivo blood flow resistance. Several groups have reported increased microcirculatory flow resistance with enhanced RBC aggregation in experiments that utilized intravital microscopy. Alternatively, whole organ studies revealed that flow resistance may be significantly decreased if RBC aggregation is enhanced. Recently, new techniques have been developed to achieve well-controlled, graded alterations in RBC aggregation without influencing suspending phase properties. Studies using this technique revealed that the effects of RBC aggregation are determined by the degree of aggregation changes, and that this relationship can be explained by different hemodynamic mechanisms
    corecore