Ultrasound effect on physical properties of corn starch

High power ultrasound (HPU) represents a non-thermal processing method that has been rapidly researched and used in the last 10 years. The application of power ultrasound offers the opportunity to modify and improve some technologically important compounds which are often used in food products. One of them is starch. The aim of this research was to examine the effect of the high power ultrasound of 24 kHz frequency on rheological and some physical properties of corn starch. Various ultrasound treatments were used; an ultrasound probe set with different intensities (34, 55, 73 W cm⁻²) and treatment times (15 and 30 min) and ultrasound bath of 2 W cm⁻² intensity and treatment times (15 and 30 min). Rheological parameters, turbidity and swelling power of corn starch suspensions were determined for native and ultrasonically treated corn starch suspensions. Differential scanning calorimetry was used in order to examine the pasting properties of corn starch. The results have shown that the ultrasound treatment of corn starch distorts the crystalline region in starch granules. The results of differential scanning calorimetry measurements have shown a decrease in enthalpy of gelatinization. A significant decrease in consistency coefficient (k) has also been observed. The consistency coefficient decreases stepwise jointly with the increasing ultrasound power. The increase in the swelling power is associated with water absorption capacity and corn starch granules solubility, respectively.     

A Phase II,Randomized, Double-Blind,Placebo Controlled,Dose-Response Trial of the Melatonin Effect on the Pain Threshold of Healthy Subjects

Background

Previous studies have suggested that melatonin may produce antinociception through peripheral and central mechanisms. Based on the preliminary encouraging results of studies of the effects of melatonin on pain modulation, the important question has been raised of whether there is a dose relationship in humans of melatonin on pain modulation.

Objective

The objective was to evaluate the analgesic dose response of the effects of melatonin on pressure and heat pain threshold and tolerance and the sedative effects.

Methods

Sixty-one healthy subjects aged 19 to 47 y were randomized into one of four groups: placebo, 0.05 mg/kg sublingual melatonin, 0.15 mg/kg sublingual melatonin or 0.25 mg/kg sublingual melatonin. We determine the pressure pain threshold (PPT) and the pressure pain tolerance (PPTo). Quantitative sensory testing (QST) was used to measure the heat pain threshold (HPT) and the heat pain tolerance (HPTo). Sedation was assessed with a visual analogue scale and bispectral analysis.

Results

Serum plasma melatonin levels were directly proportional to the melatonin doses given to each subject. We observed a significant effect associated with dose group. Post hoc analysis indicated significant differences between the placebo vs. the intermediate (0.15 mg/kg) and the highest (0.25 mg/kg) melatonin doses for all pain threshold and sedation level tests. A linear regression model indicated a significant association between the serum melatonin concentrations and changes in pain threshold and pain tolerance (R² = 0.492 for HPT, R² = 0.538 for PPT, R² = 0.558 for HPTo and R² = 0.584 for PPTo).

Conclusions

The present data indicate that sublingual melatonin exerts well-defined dose-dependent antinociceptive activity. There is a correlation between the plasma melatonin drug concentration and acute changes in the pain threshold. These results provide additional support for the investigation of melatonin as an analgesic agent. Brazilian Clinical Trials Registry (ReBec): (U1111-1123-5109). IRB: Research Ethics Committee at the Hospital de Clínicas de Porto Alegre.     

Distribution of Recombination Hotspots in the Human Genome – A Comparison of Computer Simulations with Real Data

Recombination is the main cause of genetic diversity. Thus, errors in this process can lead to chromosomal abnormalities. Recombination events are confined to narrow chromosome regions called hotspots in which characteristic DNA motifs are found. Genomic analyses have shown that both recombination hotspots and DNA motifs are distributed unevenly along human chromosomes and are much more frequent in the subtelomeric regions of chromosomes than in their central parts. Clusters of motifs roughly follow the distribution of recombination hotspots whereas single motifs show a negative correlation with the hotspot distribution. To model the phenomena related to recombination, we carried out computer Monte Carlo simulations of genome evolution. Computer simulations generated uneven distribution of hotspots with their domination in the subtelomeric regions of chromosomes. They also revealed that purifying selection eliminating defective alleles is strong enough to cause such hotspot distribution. After sufficiently long time of simulations, the structure of chromosomes reached a dynamic equilibrium, in which number and global distribution of both hotspots and defective alleles remained statistically unchanged, while their precise positions were shifted. This resembles the dynamic structure of human and chimpanzee genomes, where hotspots change their exact locations but the global distributions of recombination events are very similar.     

Development of secondary sexual characters in the seabob shrimp Xiphopenaeus kroyeri (Heller 1862) (Crustacea,Decapoda, Penaeidae): a scanning electron microscope study

The development of secondary sexual characters, the petasma, and thelycum growth were studied in Xiphopenaeus kroyeri. In adult females, the thelycum is a single plate and its anterolateral portion is characterized by a reduced hood. The aperture resembles a transverse ridge. In immature stages, the ridge has a space between the plates, which becomes narrower as it reaches the end of development. The female gonopore is ‘comma’ shaped. In adult males, the endopods of the petasma are linked at the dorsomedial margin by a large quantity of cincinnuli. In juveniles, cincinnuli gradually increase in number until they join both endopods. At the end of development the petasma is T-shaped. The male gonopore is C-shaped. The relative growth of the petasma total length versus juvenile body length showed a highly positive allometry, whereas in adults the growth was isometric. For the relationship carapace length versus thelycum width, the juvenile phase of females is characterized by an isometry and the adult phase by a negative allometry.     

Bone-marrow mononuclear cell therapy of severe ischemic heart failure

We describe cell therapy for severe ischemic heart failure using transendocardial injection of autologous bone-marrow-derived mononuclear cells. The treated patients had significantly less heart failure and angina, sustained significant improvement of pumping power, exercise capacity, cardiac muscle irrigation, and blood supply to the body. Electrical and mechanical mappings of the myocardium before and after the therapy, and anatomopathological examination of the myocardium of one of the patients that had deceased of a stroke eleven months after the treatment indicated sustained neoangiogenesis and improvement of activity and quantity of cardiomyocytes in the injected regions. Post-hoc analyses of injected cell phenotype and improvement of myocardial function indicate that presence of CD8+ and CD56+ cells does not correlate with good prognostics, suggesting a possibility of cell selection. For 'no-option' severe cardiac patients, significant benefits of cell therapy and absence of adverse effects may justify the application of bone-marrow-derived cell therapy.     

Scaling of brain metabolism with a fixed energy budget per neuron: implications for neuronal activity, plasticity and evolution

It is usually considered that larger brains have larger neurons, which consume more energy individually, and are therefore accompanied by a larger number of glial cells per neuron. These notions, however, have never been tested. Based on glucose and oxygen metabolic rates in awake animals and their recently determined numbers of neurons, here I show that, contrary to the expected, the estimated glucose use per neuron is remarkably constant, varying only by 40% across the six species of rodents and primates (including humans). The estimated average glucose use per neuron does not correlate with neuronal density in any structure. This suggests that the energy budget of the whole brain per neuron is fixed across species and brain sizes, such that total glucose use by the brain as a whole, by the cerebral cortex and also by the cerebellum alone are linear functions of the number of neurons in the structures across the species (although the average glucose consumption per neuron is at least 10× higher in the cerebral cortex than in the cerebellum). These results indicate that the apparently remarkable use in humans of 20% of the whole body energy budget by a brain that represents only 2% of body mass is explained simply by its large number of neurons. Because synaptic activity is considered the major determinant of metabolic cost, a conserved energy budget per neuron has several profound implications for synaptic homeostasis and the regulation of firing rates, synaptic plasticity, brain imaging, pathologies, and for brain scaling in evolution.