Electromyographic investigation of abdominal exercises and the effects of fatigue

Abdominal exercises are widely used to develop the anterior muscles of the trunk. These exercises can be undertaken without the aid of equipment, but increasingly manufacturers are developing equipment which purportedly enhances the training effect for abdominal muscles. As there are many different products and exercises used for abdominal muscle development, it is likely that some are more effective than others. This study aimed to investigate the effectiveness of five commonly performed abdominal exercises. A second aim was to investigate the effects of fatigue on these exercises. Five different types of abdominal exercise [standard crunch (sit-up) with bent knees, gym ball crunch, crunch with 5 kg weight held behind the head, legs raised crunch and a commercially manufactured roller crunch] were examined using integrated surface electromyography (IEMG). The lower rectus abdominis (LRA), upper rectus abdominis (URA) and obliquus externus abdominis (EO) of 15 healthy male participants [age (mean +/- SD) 22.2 +/- 6.8 years; height 1.77 +/- 0.06 m; mass 79.3 +/- 10.7 kg] were monitored using a four-channel special purpose EMG data logger. Three trials of each exercise were performed in random order and normalized to enable comparisons between muscles and exercises. At a later date, ten participants were then re-tested when fresh and after a 30 min whole-body fatigue protocol that specifically targeted the abdominal muscles. Two exercises were evaluated, the abdominal roller crunch and legs raised crunch, which were judged to be the least and most effective, respectively, of the five exercises previously used. The normalized IEMG showed significant (p < 0.001) differences between exercises (gym ball crunch = 86.0 +/- 7.5%; legs raised crunch = 79.9 +/- 5.1%; 5 kg weight crunch = 65.1 +/- 13.4%; standard crunch = 56.2 +/- 3.2%; and roller crunch = 45.0 +/- 11.4%). Post-fatigue, the normalized mean IEMG for both exercises increased significantly (p < 0.05) for LRA and URA muscles but not for the EO (p > 0.05). It was concluded that exercises can be constructed to provide a greater challenge to abdominal muscles, commercially available roller-type equipment appears to be little different from the standard abdominal crunch with bent knees, and fatiguing exercise results in the LRA and URA being more highly activated. These findings provide more detailed knowledge and understanding of the effects of different forms of abdominal exercise.     

Electrophysiological and chemical analysis of sex pheromone communication system of the mottled umber,Erannis defoliaria (Lepidoptera: Geometridae)

(Z,Z,Z)-3,6,9-nonadecatriene (Z3,Z6,Z9–19Hy) and (Z,Z)-3,9-cis-6,7-epoxy-nonadecadiene (Z3,Z9-cis-6,7-epo-19Hy) were identified in pheromone gland extracts from femaleErannis defoliaria. The two components were found in a 13 ratio, with the main component,Z3,Z9-cis-6,7-epo-19Hy present at an amount of about 1.5 ng per female. The components were identified by means of gas chromatography-mass spectrometry, gas chromatography-electroantennography and gas chromatography-single sensillum recordings. Single sensillum measurements on the male antenna showed two physiological types of sensilla. One type was characterized by a large spike amplitude cell responding toZ3,Z9-cis-6,7-epoxy-19Hy and a small spike amplitude cell responding toZ3,Z6,Z9–19Hy. A second type responded only with a large spike amplitude cell to the epoxide, and this cell was inhibited by the triene. Of the two pheromone components, the epoxide gave the higher response in the EAG tests. Preliminary field tests support the identification of the pheromone components. The epoxide was also found to be present in the extract of the pheromone gland ofColotois pennaria, and males ofC. pennaria andAgriopis marginaria were trapped by the mixture of the identified compounds.     

Family functioning and mood disorders: A comparison between patients with major depressive disorder and bipolar I disorder.

Within a sample of patients with major depressive disorder (MDD; n = 121) and bipolar affective disorder (BPAD; n = 69), the authors examined (a) diagnostic differences in family functioning at acute episode, (b) diagnostic differences in family functioning at episode recovery, (c) within-group changes in family functioning from acute episode to recovery, and (d) whether within-group changes from acute episode to recovery varied by diagnosis. Using a multidimensional model, the authors evaluated interviewer, patient, and family ratings. Overall, patients with MDD and BPAD evidenced similar levels of family impairment at acute episode and recovery. Generally, patients in both groups experienced improvement in family functioning over time, yet mean scores at recovery continued to range from fair to poor. Although certain specific differences emerged, diagnostic groups appeared to be more similar than different in level and pattern of family functioning. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

In-situ X-ray absorption study of evolution of oxidation states and structure of cobalt in Co and CoPt bimetallic nanoparticles (4 nm) under reducing (H2) and oxidizing (O2) environments

In-situ near edge X-ray absorption fine structure spectroscopy was performed to monitor the oxidation states of Co and CoPt nanoparticles (NPs) of 4 nm size in the presence of H(2) and O(2) in the pressure range of 1 bar and 36 Torr respectively. Platinum helps the rapid reduction of cobalt oxides in hydrogen at a rather low temperature (38 °C). In addition, reversible changes of the oxidation states of cobalt in the Co and CoPt NPs as a function of cycling oxygen pressure (in the range of millitorr to 36 Torr) are quantified and compared. The role of Pt in the process of Co reducing and oxidizing was explored. Our findings permit the prediction of the cobalt oxidation states as the reaction conditions are altered. The experimental results also suggest the presence of tetrahedral structure of Cobalt oxide that differs from the Co(3)O(4) spinel structure.     

Size-controlled model Co nanoparticle catalysts for CO₂ hydrogenation: synthesis, characterization, and catalytic reactions

Model cobalt catalysts for CO(2) hydrogenation were prepared using colloidal chemistry. The turnover frequency at 6 bar and at 200-300 °C increased with cobalt nanoparticle size from 3 to 10 nm. It was demonstrated that near monodisperse nanoparticles in the size range of 3-10 nm could be generated without using trioctylphosphine oxide, a capping ligand that we demonstrate results in phosphorus being present on the metal surface and poisoning catalyst activity in our application.     

Lessons from the Use of an Active Production Well for Compliance Monitoring in the Great Artesian Basin, Australia

Wellfield B, in the Great Artesian Basin (GAB), supplies 30 ML/day of fresh groundwater to BHP Billiton’s Olympic Dam mine and the town of Roxby Downs in South Australia. Groundwater use from Wellfield B is regulated according to the regional effects on pressures in the aquifer. Drawdown assessment criteria (allowing a maximum of 5?m as pressure drawdown measured in piezometers) were set at five sites, including two active pastoral production wells that existed prior to the commissioning of Wellfield B. Aquifer pressure in these production wells was measured after a predetermined recovery time. Pastoral flow was eliminated in 2009/10 in one of the wells, providing an opportunity to assess whether antecedent flow had affected the measured pressures and therefore the reported apparent drawdown. In the GAB, the combination of deep wells, high pressures, and hot water make flow and pressure measurements and the calculation of head more challenging than in cold aquifers. Pressures measured at the well head often decrease during recovery, and the influence of temperature has to be incorporated in head calculations. Based on one example, Jackboot Bore, it is clear that recovery times in the order of months are required, which is impractical. Hence, the use of an active production well for assessing compliance with drawdown criteria is not recommended in the GAB.     

Random speckle modulation technique for laser interferometry

In spite of its obvious advantages over conventional contact and immersion techniques, laser interferometry has not yet become a practical tool in ultrasonic nondestructive evaluation since its sensitivity is insufficient in most practical applications. Part of the problem is that the maximum signal-to-noise ratio often cited in scientific publications and manufacturers' specifications cannot be maintained on ordinary diffusely reflecting surfaces. Although these surfaces reflect a fair amount (5–50%) of the incident laser light, this energy is randomly distributed among a large number of bright speckles. Unless the detector happens to see one of these bright speckles, the interferometer's signal-to-noise ratio will be much lower than the optimum. This adverse effect is almost completely eliminated by the suggested random speckle modulation technique. The conventional interferometric technique was modified to assure random occurrence of a few very bright speckles and to move the whole speckle pattern around at an appropriate speed. Random but frequent bright flashes detected from the surface of the specimen resulted. The bright periods are 0.1 ms or longer, sufficient to trigger the ultrasonic pulser and detect the transmitted signals before the flash subsides. As much as 5–10 times improvement of the optical sensitivity was achieved by this novel approach and close to maximum signal-to-noise ratio was maintained everywhere on the surface of a diffuse object.     

Near-infrared probe for in situ characterization of nafion thin films

A near-infrared (NIR)-absorbing cyanine dye was used as a probe for in situ characterization of Nafion thin films. This NIR dye was very sensitive to changes in the hydrophobicity of the environment and proved to be very suitable for probing the Nafion coatings, which involve a two-Phase structure of hydrophobic and hydrophilic zones. Sorption phenomena of water and aqueous alkali salt solutions by Nafion were investigated. For our study systems of thin-coating films prepared from 5% wt alcoholic solution of Nafion 117, the absorption spectrum was dominated by higher-order aggregates when in dry form. In pure water, the absorption maximum of the monomer dye appears at 773 nm and can be used as an indication of the swelling process of the film. The water uptake reaches saturation in only a few seconds. After the swelling process, an additional absorption band with a maximum at 555 nm appears primarily at the expense of the NIR monomer dye absorption band. The peak transition process, which is a very slow process and is a strong function of the water content inside the matrix, can be used as an indication of the establishment of equilibrium between the two-phase structure due to the water uptake. Since the absorption maximum of the study system is around 800 nm, semiconductor lasers can be used. This technique shows high potential in other applications where polymers are used as support material, e.g., in situ thin-film thickness measurements. In the study, the feasibility of this approach was illustrated.