Comprehensive Seepage Assessment: Beaver Dam, Arkansas

A general philosophy of the role of engineering geology and engineering geophysics in seepage assessment is presented. Practical application of this philosophy is illustrated by a case history. A large dike continues to have anomalous seepage in spite of pre-construction and postconstruction grouting. The dike is founded over a graben of cavernous limestone with about a 200-ft. vertical offset along the bounding fault zones, which are horizontally separated by about 1000 ft. Objectives of the seepage assessment program were to define the geological and hydrological conditions beneath the dike in sufficient detail to allow rational remedial planning. Integration of results of a geophysical investigation with the overall assessment program is emphasized: preliminary interpretation of the geophysical results is used to site new piezometers; detailed analysis of the geophysical results is used to site exploratory borings; feedback from exploratory borings and new piezometers is used to refine geophysical interpretation

Characterization of Protein Metabolism in Undifferentiated and Differentiated Murine Muscle Tissue

The emergence of cell culture experiments have greatly expanded the understanding of skeletal muscle physiology. However, there is a paucity of data regarding the behaviors of cells grown in culture at various stages versus in vivo. This preliminary set of studies was designed to assess alterations of anabolic responses between undifferentiated and differentiated muscle tissue in [high] and [low] glucose media along with varying dosages of insulin. Purpose: Determine if there is a disparity in fractional synthesis rates (FSR) between C2C12 myoblasts and myotubes with varying levels of insulin and in [high] (4.5g/L) and [low] glucose (2.75 g/L) media. Methods: All cells that were going to be differentiated were started on a [high] glucose differentiation media for 48 hours. The [high] glucose differentiation media was continually applied for the [high] glucose group until harvest of the cells. The [low] glucose media group had the [high] glucose differentiation media removed and [low] glucose differentiation media was applied for 48 hours until the cells were harvested. Both [low] and [high] glucose groups received three different levels of insulin. T-25’s received either 75 µL, 150 µL, or 300 µL. T-75’s 195 µL, 390 µL, and 780 µL. Deuterium oxide was applied 24 hours prior to harvest of the cells at a level of 4%. Results: Preliminary data demonstrates that differentiated murine myotubes have slightly elevated FSR than undifferentiated myoblasts (p\u3c0.013). When insulin was added to the growth media, FSR was found to be elevated in undifferentiated cells compared to controls (p\u3c0.05). Within the differentiated myotubes, the [low] glucose myotubes had higher FSR than myotubes that were incubated in [high] glucose myotubes (p\u3c0.001). There was also no difference in FSR based on flask size for either the undifferentiated (p\u3e0.181) or differentiated (p\u3e0.464) C2C12’s. Conclusion: Future investigators must be aware of the ratio of undifferentiated cells and differentiated myotubes as this ratio could confound results as myoblasts are still present even at later stages of differentiation. Current protocols for differentiation media, regarding insulin addition, provide for optimal anabolic responses. Elevated FSR rates in the myotubes fed [low] glucose media could be explained by the cells having a higher turnover rate of cellular proteins

Partial or Complete Unloading of Skeletal Muscle Leads to Specific Alterations of Anabolic Signal Transduction

Consequences of disuse atrophy of skeletal muscle observed during spaceflight on astronaut health and performance are a focal point of space research. Decrements of both muscle mass and protein synthesis rates have been observed with exposure to varying muscle loading environments (1G \u3e partial loading \u3e 0G), and most of the reduced muscle mass can be attributed to diminished rates of synthesis. However, specific mechanisms behind unloading-dependent reductions of protein synthesis are not well defined. PURPOSE: To determine whether or not alterations of anabolic signal transduction was responsible for the changes previously observed in fractional synthesis rates with specific gravitational loading paradigms. METHODS: Female BALB/cByJ were normalized by bodyweight and assigned to normal cage ambulation (1G), partial weight bearing suspension titrated to approximately 33% bodyweight (G/3), partial weight bearing titrated to 16% bodyweight (G/6) and full unloading of hind limbs (0G) in specially designed cages. All mice were subjected to that loading environment for 21d prior to tissue harvest, and monitored daily. Immunoblotting of the gastrocnemius (n=23) was carried out to analyze alterations of anabolic signal transduction. Although numerous signaling intermediates were assessed, the focus of this abstract will be on ribosomal protein S6 kinase (p70-S6K). This important protein has served as a marker of protein synthesis signal transduction as well as the anabolic capacity in skeletal muscle. RESULTS: Regardless of loading paradigm, no differences were detected among groups for the activation of p70-S6K (as indicated by the phospho: total protein content). Total protein content, however, was ~27% lower than control in 0G and G/3 (P=0.008) with G/6 not being different from control (P\u3e0.05). CONCLUSION: In combination with previous data (unpublished observations), Partial gravitational fields at least partially rescues anabolic signaling, suggesting that a threshold level of stimulus is necessary to maintain anabolic capacity in muscle. These results may have important implications towards the development of strategies designed to counter the effects of partial/complete unloading on skeletal muscle based on how the anabolic capacity of muscle is affected

Two-dimensional Bose-Einstein Condensation in Cuprate Superconductors

Transition temperatures $T_{c}$ calculated using the BCS model electron-phonon interaction without any adjustable parameters agree with empirical values for quasi-2D cuprate superconductors. They follow from a two-dimensional gas of temperature-dependent Cooper pairs in chemical and thermal equilibrium with unpaired fermions in a boson-fermion (BF) statistical model as the Bose-Einstein condensation (BEC) singularity temperature is approached from above. The {\it linear} (as opposed to quadratic) boson dispersion relation due to the Fermi sea yields substantially higher $T_{c}$'s with the BF model than with BCS or pure-boson BEC theories.Comment: 7 pages including 2 figure

One-dimensional Cooper pairing

We study electron pairing in a one-dimensional (1D) fermion gas at zero temperature under zero- and finite-range, attractive, two-body interactions. The binding energy of Cooper pairs (CPs) with zero total or center-of-mass momentum (CMM) increases with attraction strength and decreases with interaction range for fixed strength. The excitation energy of 1D CPs with nonzero CMM display novel, unique properties. It satisfies a dispersion relation with \textit{two} branches: a\ phonon-like \textit{linear }excitation for small CP CMM; this is followed by roton-like \textit{quadratic} excitation minimum for CMM greater than twice the Fermi wavenumber, but only above a minimum threshold attraction strength. The expected quadratic-in-CMM dispersion \textit{in vacuo }when the Fermi wavenumber is set to zero is recovered for \textit{any% } coupling. This paper completes a three-part exploration initiated in 2D and continued in 3D.Comment: 12 pages, 6 figure

Autophagy is Required for the Anabolic Response to Muscle Contraction

Exercise is a key stimulus in regulating the behavior and metabolism of skeletal muscle, with exercise inducing muscular growth through activation of the anabolic mechanistic target of rapamycin kinase (mTOR). Separately, there is mounting evidence that exercise increases autophagy (one of the main routes by which intracellular proteins are degraded) and that the autophagic process may indeed be required for adaptations to exercise training. PURPOSE: To investigate the effects of autophagy inhibition on mTOR signaling and cellular anabolism after muscular contraction. METHODS: Cultured L6 myotubes were to exposed to electrical pulse stimulation using a stimulator set to deliver bipolar pulses of 30V at 100 Hz for 200 ms every fifth second for 60 minutes. Subsequently, cells received either vehicle control, or 100 μM NSC-185058, an antagonist of the key autophagy protein ATG4B and known inhibitor of autophagy. All groups were also exposed to 4% deuterium oxide, a stable isotopic tracer for measurements of protein synthesis. 24 hours post “exercise” bout, cells were lysed in ice-cold Norris buffer, and prepared for Western immunoblot of protein expression, or determination of protein fractional synthesis rate (FSR) of the myofibrillar fraction via mass-spectrometry analysis. Non-stimulated cells receiving vehicle control treatment served as controls, with a one-way analysis of variance and Tukey’s post-hoc test used to test for any differences between groups. RESULTS: We found that phosphorylation of a key downstream target of mTOR, P70S6 kinase, was roughly seven times greater in cells subjected to EPS and vehicle control (710.3%) relative to control (p0.05). While there was a trend for EPS treatment to increase expression of ATG4B, along with a reduction of ATG4B content as a result of NSC-185058 treatment, this finding did not rise to the level of statistical significance. There were no differences in FSR between cells exposed to EPS; however, NSC-185058 treatment significantly reduced FSR in EPS treated cells relative to controls (0.8712 %/hr vs 1.193 %/hr). CONCLUSION: These findings present two conclusions: high-intensity EPS as an in vitro model of exercise elevates mTOR signaling through P70S6K 24 hours post exercise, and mTOR activation as a result of muscular contraction is reliant upon autophagy in skeletal muscle. Further work will be required to elucidate the dynamics of this relationship, and the interplay between skeletal muscle autophagy and anabolism

West-Central Asia: a comparative analysis of students’ trajectories in Russia (Moscow) from the 1980s and China (Yiwu) from the 2000s

Through an exploration of oral history and ethnographic material, this article makes a comparative examination of the life-trajectories of students from Yemen, Iraq, and Afghanistan who studied in Russia (Moscow) during the late 1980s, and from Tajikistan, Iran, Azerbaijan and Saudi Arabia who studied in China in the 2000s. In contrast to the cohort of students in Moscow who were mainly men from places with relatively amicable relations with the USSR, the female students of Muslim background from West and Central Asia regarded China as a place where they could pursue fulfilling forms of economic and personal autonomy. By comparing these two groups of international students, this article sheds light into the nature of historical, geographical and geopolitical connections and disconnections between West-Central Asia, Eurasia (especially Russia) and East Asia (especially China). By centring its attention to the demise of Soviet/Russian education and the emergence of China as a figure of economic prosperity, the article theorises West-Central Asia as a particular arena of interaction suitable to comprehend the networks, ‘third spaces’ or zones of interaction (e.g. Moscow and Yiwu), and forms of connection fostered by these students’ trajectories

A New Interpretation of Flux Quantization

We study the effect of Aharonov-Bohm flux on the superconducting state in metallic cylinders. Although Byers and Yang attributed flux quantization to the flux-dependent minimum of kinetic energies of the Cooper pairs, it is shown that kinetic energies do not produce any discernible oscillations in the free energy of the superconducting state (relative to that of normal state) as a function of the flux. This result is indeed anticipated by the observation of persistent current in normal metal rings at low temperature. Instead, we have found that pairing interaction depends on the flux, leading to flux quantization. When the flux $(\Phi$) is given by $\Phi=n\times hc/2e$ (with integer n), the pairing interaction and the free energy become unchanged (even n) or almost unchanged (odd n), due to degenerate-state pairing resulting from the energy level crossing. As a result, flux quantization and Little-Parks oscillations follow.Comment: Revtex, 10 pages, 6 figures, For more information, send me an e-mail at [email protected]

Dilation of the Giant Vortex State in a Mesoscopic Superconducting Loop

We have experimentally investigated the magnetisation of a mesoscopic aluminum loop at temperatures well below the superconducting transition temperature $T_{c}$. The flux quantisation of the superconducting loop was investigated with a $\mu$-Hall magnetometer in magnetic field intensities between $\pm 100 {Gauss}$. The magnetic field intensity periodicity observed in the magnetization measurements is expected to take integer values of the superconducting flux quanta $\Phi_{0}=h/2e$. A closer inspection of the periodicity, however, reveal a sub flux quantum shift. This fine structure we interpret as a consequence of a so called giant vortex state nucleating towards either the inner or the outer side of the loop. These findings are in agreement with recent theoretical reports.Comment: 12 pages, 5 figures. Accepted for publication in Phys. Rev.