Image-analysis-based assessment of the effects of the "Ca2+-jump" technique on sarcomere uniformity

A new image analysis-based technique was used to quantitatively examine the effects of the "Ca2+-jump" activation protocol on the maintenance of fiber quality in skinned rabbit psoas muscle fiber segments. Specifically, contractions in pCa 4.6 were preceded by short-duration "preactivation" soaks in a solution in which EGTA was replaced with the low-Ca2+ buffering capacity analog hexamethylenediamine-N, N, N', N'-tetraacetate, which facilitated rapid Ca2+ equilibration within the fiber segments. Fiber quality was assessed by examining the Fourier spectra of the muscle fiber images before, during, and after activation. Segment lengths were typically below 500 micrometer, thus allowing the majority of the sarcomeres to be visualized in the field of view (x200 and x400 magnification). The preactivation protocol resulted in less deterioration of fiber quality with repetitive activation. In addition, there was also a significant reduction in the time required to reach the 50% level of maximum tension, with no significant change in the maximum tension level.     

Numerical modelling and characterization of nanofiltration membranes for the separation of carbohydrate mixtures

The results of an experimental and computational investigation of the selective separation of carbohydrates on nano‐membranes in cross‐flow filtration are reported. Two commercial membranes (NF270‐400 and TFC‐SR3) were characterised in terms of permeability and rejection of carbohydrate solutions. It is shown that the membranes can be used to recover glucose and galactose from their mixtures with lactose. The permeate flux is shown to depend on sugar concentration, with permeate flux decreasing as the concentration increases. Quantitative evaluation using numerical analysis of the above flow and separation process showed that the performance of nano‐membranes can be captured and reproduced with sufficient accuracy, thereby reducing the number of experiments require to evaluate the suitability of membranes in different applications. A Fickian approach is adopted to model the separation, and is shown to be effective.     

Isolation and initial characterization of a newfound hantavirus from California

A fatal case of hantavirus pulmonary syndrome (HPS) in northern California prompted our attempt to isolate viruses from local rodents. From tissues of two deer mice, Peromyscus maniculatus, two hantaviruses (Convict Creek virus 107 and 74, CC107 and CC74) were established in cell culture. Viral antigens, proteins, and RNAs of the first and archetypical isolate (CC107) were examined, and portions of the medium (M) and small (S) genome segments of both isolates were sequenced. Antigenically, CC107 virus and the second isolate, CC74 virus, were more closely related to Puumala virus than Hantaan (HTN) virus, though distinct from both. Northern blots of viral RNAs showed the large and M segments of CC107 to be the same size as those of HTN virus, whereas the S segment was larger. Protein gels did not reveal CC107 to have a substantially larger nucleocapsid protein than HTN virus. Partial nucleotide sequence comparisons of CC107 and CC74 viruses revealed their M segments to be highly similar to one another, while their S segments differed by more than 10%. Nucleotide and deduced amino acid sequence comparisons showed the California isolates to be closely related to the newfound hantaviruses first detected in the Four Corners area and since incriminated in HPS through wide areas of the United States.     

Episodic multiregional cortical coherence at multiple frequencies during visual task performance

The way in which the brain integrates fragmentary neural events at multiple locations to produce unified perceptual experience and behaviour is called the binding problem. Binding has been proposed to involve correlated activity at different cortical sites during perceptuomotor behaviour, particularly by synchronization of narrow-band oscillations in the gamma-frequency range (30-80 Hz). In the rabbit olfactory system, inhalation induces increased gamma-correlation between sites in olfactory bulb and cortex. In the cat visual system, coherent visual stimuli increase gamma-correlation between sites in both the same and different visual cortical areas. In monkeys, some groups have found that gamma-oscillations transiently synchronize within striate cortex, superior temporal sulcus and somatosensorimotor cortex. Others have reported that visual stimuli produce increased broad-band power, but not gamma-oscillations, in several visual cortical areas. But the absence of narrow-band oscillations in itself does not disprove interregional synchronization, which may be a broad-band phenomenon. We now describe episodes of increased broad-band coherence among local field potentials from sensory, motor and higher-order cortical sites of macaque monkeys performing a visual discrimination task. Widely distributed sites become coherent without involving other intervening sites. Spatially selective multiregional cortical binding, in the form of broad-band synchronization, may thus play a role in primate perceptuomotor behaviour.     

The Impact of Dietary Interventions on the Symptoms of Inflammatory Bowel Disease: A Systematic Review

Diet may be a successful part of the treatment plan for improving outcome in patients with inflammatory bowel disease (IBD). This study aimed to systematically review all published clinical trials evaluating the effects of a regular diet on symptoms of IBD. Three medical databases were searched for clinical trials evaluating an intervention that involved dietary manipulation using a regular diet on adults with IBD whose symptoms were objectively measured before and after the intervention. The most common types of regular diet interventions that we observed in the literature fell into the following three categories: low residue/low fiber diets, exclusion diets, or other specific diets. Of all included studies, the few that were of higher quality and that observed a statistically significant improvement in symptoms in the diet group compared to the control group fell under the exclusion diet group or the other specific diet group. We were able to identify several high quality clinical trials evaluating dietary manipulations on symptoms of IBD. Exclusion diets and the low FODMAP diet are two areas identified in this review that show promise for having therapeutic benefits for patients with IBD.     

Changes in electrical activity of rabbit olfactory bulb and cortex to conditioned odor stimulation.

Rabbits with chronically implanted electrodes in olfactory bulb and cortex were classically conditioned to give an increase in relative frequency of sniffing to odor stimuli (CS+) reinforced with mild electric shock. Electroencephalographic high-frequency (35–85 Hz) bursts were recorded from an ensemble of nine bulbar depth electrodes and a second ensemble of 50 cortical surface electrodes. The olfactory cortex responded to the CS+ with sustained elevation of burst amplitude even though the olfactory bulb, from which it receives its primary centripetal input, underwent a marked decline in burst amplitude during the same time period. The amplitude reduction was not spatially uniform: The burst of the bulbar region that declined most in amplitude had the greatest phase lag with respect to the bulbar ensemble average burst. These effects were learning related because they did not occur for CS+ trials at the beginning of conditioning or for unreinforced control trials at any time. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Engaging middle school students in scientific practice with a collaborative mobile game

Previous research using collaborative mobile augmented reality games in science education revealed that such games can be used to promote learner engagement and have found that engagement in such mobile games is related to flow. This study investigated whether player's flow experience differed by achievement track, gender, or gender composition of working groups. In an urban school district, 202 students from two eighth‐grade science classes participated in a collaborative mobile science game. Data included a self‐report survey collected after the game that measured player's flow experience. Using a regression model, the relationship of flow experience with achievement track and gender was explored while controlling for group composition and teacher effects. The study found that gender was related to flow experience; specifically, girls reported higher flow experience scores (d = 0.30). Flow experience did not have a statistically significant relationship with achievement track showing that the activity engaged all observed students similarly.     

Use of Direct Viable Count Methodology With Ozonation in Drinking Water

Viable cells were detected by direct viable count methodology on ozonated anthracite taken from an active dual media rapid sand filter. Also, at least a thousand fold more cells were determined to be viable by direct viable count methodology than by the heterotrophic plate count in raw water which had been exposed to ozone. This suggests that bacterial cells were not killed as quickly by ozone as previously thought, and that the direct viable count may have a place in assessing the effectiveness of killing bacteria by ozone.