The purpose of this study was to use a wavelet analysis designed specifically for surface mechanomyographic (MMG) signals to examine the MMG responses of the vastus lateralis (VL), rectus femoris ...(RF), and vastus medialis (VM) muscles. Fifteen healthy men age (mean ± SD): 26.4 ± 6.1 years volunteered to perform isometric muscle actions of the dominant leg extensors at 20%, 40%, 60%, 80%, and 100% of the maximum voluntary contraction (MVC). During each muscle action, surface MMG signals were detected from the VL, RF, and VM and processed with the MMG wavelet analysis. The results show that, for the VL and VM muscles, there was compression of the total MMG intensity spectra toward low frequencies for most force levels above 20% MVC. For the RF, however, the peak of the total MMG intensity spectrum occurred at approximately 30–40 HZ for all force levels. Because the VL, RF, and VM are all innervated by the femoral nerve, the discrepancies among the three muscles for total MMG intensity in each wavelet band may have been due to differences in architecture, muscle stiffness, and/or intramuscular pressure. Muscle Nerve 39: 355–363, 2009
Recombinant expression of the aryl hydrocarbon receptor (AhR) yields small amounts of ligand-binding-competent AhR. Therefore,
Spodoptera frugiperda (
Sf9) cells and baculovirus have been evaluated ...for high-level and functional expression of AhR. Rat and human AhR were expressed as soluble protein in significant amounts. Expression of ligand-binding-competent AhR was sensitive to the protein concentration of
Sf9 extract, and coexpression of the chaperone p23 failed to affect the yield of functional ligand-binding AhR. The expression system yielded high levels of functional protein, with the ligand-binding capacity (
B
max) typically 20-fold higher than that obtained with rat liver cytosol. Quantitative estimates of the ligand-binding affinity of human and rat AhR were obtained; the
K
d for recombinant rat AhR was indistinguishable from that of native rat AhR, thereby validating the expression system as a faithful model for native AhR. The human AhR bound TCDD with significantly lower affinity than the rat AhR. These findings demonstrate high-level expression of ligand-binding-competent AhR, and sufficient AhR for quantitative analysis of ligand binding.
Bar trajectory during weightlifting movements is related to the position of the body during the lift and the displacement of the feet during the drop-under phase. The purpose of this study was to ...examine anterior-posterior foot displacement and its relationship with performance in the snatch of collegiate weightlifters. Snatch attempts of men weightlifters from the 1998 U.S.A. Weightlifting Collegiate National Championships were analyzed for horizontal displacement of the feet by video analysis. Lifts were analyzed under 2 conditions: all lifts combined and the heaviest successful attempt for each lifter. Lifts (n = 74) were placed into 4 groups: forward displacement (FD, >2.5 cm); no displacement (ND, +/-2.5 cm); rearward displacement (RD, >2.5 cm); and those that showed asymmetric (AS, >7 cm difference in right and left foot) displacement of the feet. Chi-square revealed no significant difference in success rate between groups for all attempts. No statistically significant differences were noted between groups in body mass to bar mass ratio or Sinclair formula for heaviest successful attempts. Results indicate that foot displacement did not significantly affect snatch success or lifting ability in collegiate national level lifters.
Ghrelin, a 28 amino acid, octanoylated peptide, is an endogenous ligand for the growth hormone secretagogue receptor (GHS-R). In addition to various endocrine functions, including stimulation of GH ...release, ghrelin has been characterized as an important regulator of energy homeostasis. Ghrelin administration has been shown to increase adiposity in rodents and stimulate food intake in humans. Studies suggest that these orexigenic effects are mediated primarily through GHS-R expression in hypothalamic and pituitary neuronal pathways. In this context, GHS-R has been recognized as a potential target for the treatment of GH deficiency and body weight disorders. Cell lines provide convenient in vitro systems to identify and characterize potential pharmacophores and to analyze GHS-R functional activity. While recombinant cell lines that overexpress GHS-R have served as effective research tools for these studies, such cell lines may differ in signaling response to ghrelin compared with hypothalamic or pituitary cells expressing GHS-R. We show here that a cell line derived from a rat anterior pituitary adenoma, RC-4B/C, expresses endogenous GHS-R as judged by reverse transcriptase-PCR. In a Ca(2+)mobilization assay, RC-4B/C cells demonstrate a dose-dependent increase in intracellular Ca(2+) on stimulation with rat ghrelin and a related peptide agonist, hexarelin (EC(50), 1.0 nM and 1.7 nM respectively), but are unresponsive to treatment with inactive des-octanoyl rat ghrelin. A subclone, RC-4B/C.40, with a more robust and stable ghrelin response, was isolated from the parental population of cells to allow further analysis of GHS-R signal transduction. Using pertussis toxin and the phospholipase C inhibitor U-73122, we show that ghrelin signals through the Gq pathway in the RC-4B/C.40 cells. We also demonstrate that the ghrelin-induced rise of intracellular Ca(2+) in RC-4B/C.40 cells involves initial Ca(2+)release from intracellular stores followed by a sustained elevation that occurs via influx of extracellular Ca(2+) through ion channels. In addition, unlike observations reported in recombinant cell systems, the RC-4B/C.40 cells do not exhibit a high level of GHS-R constitutive activity as determined in a phosphatidylinositol hydrolysis assay. Overall, the data presented here suggest that the RC-4B/C parental and RC-4B/C.40 cells provide novel in vitro systems for the characterization of GHS-R pharmacophores and ghrelin signaling.
The charts of 480 patients with secondary bacterial peritonitis were reviewed. The antibiotics used were compared with the culture and sensitivity data obtained at surgery, and the outcomes of ...patients were evaluated. Patients treated with a single broad-spectrum antibiotic had a better outcome than patients treated with multiple drug treatment. Inadequate empiric antibiotic treatment was associated with poorer outcome than any other type of treatment. The outcome of this inadequate treatment group could not be improved by any antibiotic response to culture and sensitivity information after operation. Those patients treated with antibiotic coverage for anticipated organisms and having no cultures taken did as well as patients having cultures taken. Surgeons typically ignore culture data after operation, and only 8.8% of patients in this study had an appropriate change in antibiotic treatment after operation. A benefit from obtaining operative cultures could not be identified.
The sheepshead minnow,
Cyprinodon variegatus, is a widespread fish species that typically inhabits coastal tidal marsh and mangrove swamp environments, ranging from Cape Cod, Massaschusetts to ...northern Mexico and into the Caribbean. This wide range crosses several biogeographic boundaries which are coincident with genetic structuring within numerous species originating in the Pleistocene. In addition, the more northerly reaches of this species range have been further subject to the evolutionary consequences of Pleistocene glaciation due to local extinction and recolonization of formerly glaciated sites.
C. variegatus thus provides an excellent vertebrate model system within which to test the extent of genetic differentiation among populations in a dominant coastal ecosystem and examine patterns of historical demography in populations distributed along a latitudinal gradient. Using mitochondrial control region and ND2 sequence data, we discovered monophyletic clades within
C. variegatus with divergence times within the Pleistocene, and very low gene flow between most sites. Intraspecific genetic breaks appear to correspond broadly to biogeographic or oceanic boundaries. Pleistocene climate change appears to have had dramatic impacts on the size and distribution of populations within and near the glacial margins, but has also affected populations far from formerly glaciated regions.
The solutions to the world's current and future problems require that engineers and scientists design and construct ecologically and socially just systems within the carrying capacity of nature ...without compromising future generations. In addition, as governments move towards policies that promote an international marketplace, educators need to prepare students to succeed in the global economy. Young people entering the workforce in the upcoming decades will also have the opportunity to play a critical role in the eradication of poverty and hunger and facilitation of sustainable development, appropriate technology, beneficial infrastructure, and promotion of change that is environmentally and socially just.
Many universities espouse the idea that discipline integration is a prerequisite for successful implementation of sustainability in education. However, few engineering curriculum have taken the step to integrate concepts of sustainable development with an international experience. This paper discusses the educational and global drivers for curricular change in this important area and demonstrates how several undergraduate and graduate programmes initiated at Michigan Technological University can provide a more interdisciplinary basis for educating engineers on global concepts of sustainability. To date, these programmes have taken place in 21 countries and reached approximately 300 students (49% women) that represent 11 engineering disciplines and nine non-engineering disciplines.
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