bluuebunny/crossref_metadata_2025 huggingface dataset:
Globalization and legal change: The “Americanization” of European law?
Authors: Kagan Robert A.
Published: May 2007

Intensified global economic competition, economic liberalization, and the rise of EU governance have led some observers to argue that there has been a trend toward the “Americanization” of the European “way of law.” This article addresses that contention, focusing on legal change in European member states. It first describes ways in which the American legal tradition has differed most sharply from the national legal systems of Western Europe (including Great Britain) and the political and economic factors that account for this “American legal distinctiveness.” Similar political and economic factors currently are at work in Europe, the article acknowledges, creating incentives for legal convergence. But it also argues that European legal culture and the political organization of European national states generate path‐dependent forces that impede European movement toward American ways of law, and it discusses six important differences between European and American law that remain entrenched and are unlikely to disappear.
Casino Cities
Authors: Hannigan John
Published: May 2007

The recent upsurge in licensed, themed gambling emporiums in Macao, South Africa, and Britain signals the emergence of the casino city as a global model of urban development and consumer culture. Casino cities thrive at the intersection of three complementary commercial spheres: the luxury goods and services industry, the corporate gaming (gambling) sector, and the international tourist trade. Critics have expressed concern that the casino city is encased in a straightjacket of blandness and predictability. Furthermore, it tends to steamroll indigenous culture and heritage, or alternately, co‐opt it in order to create the illusion of the exotic. Finally, the casino city is a dual city where enclaves of conspicuous consumption and spectatorship are juxtaposed to areas of poverty and despair.
Modeling Pre‐ and Post‐Dam Removal Sediment Dynamics: The Kalamazoo River, Michigan1
Authors: Wells Robert R. , Langendoen Eddy J. , Simon Andrew
Published: May 2007

Abstract:  The state of Michigan is interested in removing two low‐head dams in an 8.8 km reach of the Kalamazoo River between Plainwell and Otsego, Michigan, while minimizing impacts locally and to downstream reaches. The study was designed to evaluate the erosion, transport, and deposition of sediments over a 37.3‐year period using the channel evolution model CONCEPTS for three simulation scenarios: Dams In (DI), Dams Out (DO), and Design (D). The total mass of sediment emanating from the channel boundary, for the DI case, shows net deposition of 4,100 T/y for the study reach, with net transport (suspended and bed load) of 10,500 T/y passing the downstream boundary. For the DO case, net erosion is 19,200 T/y with net transport of 30,100 T/y (187% increase) passing the downstream boundary. For the D case, net deposition is 2,570 T/y (37% decrease) with transport of 14,200 T/y (35% increase) passing the downstream boundary. The most significant findings were: (1) removal of the low‐head dams will cause significant erosion of sediments stored behind the dams and increased sediment loads passing the downstream boundary and (2) sediment loads for the proposed channel design are similar to existing conditions and offer reduced fine‐sediment loadings.
TRPM7 channel is sensitive to osmotic gradients in human kidney cells
Authors: Bessac Bret F. , Fleig Andrea
Published: May 2007

TRPM7 (transient‐receptor‐potential melastatin 7) is an ion channel with α‐kinase function. TRPM7 is divalent‐selective and regulated by a range of receptor‐stimulated second messenger pathways, intracellular Mg‐nucleotides, divalent and polyvalent cations and pH. TRPM7 is ubiquitously found in mammalian cells, including kidney, the responsible organ for osmolyte regulation, posing the question whether the channel is osmosensitive. Recent reports investigated the sensitivity of native TRPM7‐like currents to cell swelling with contradictory results. Here, we assess the sensitivity of TRPM7 to both hypo‐ and hyperosmotic conditions and explored the involvement of the channel's kinase domain. We find that hypotonicity facilitates TRPM7 at elevated intracellular magnesium and Mg·ATP (3–4 mm), but has no effect in the absence of these solutes. Hypertonic conditions, in contrast, inhibit TRPM7 with an IC50 of 430 mosmol l−1. This inhibitory effect is maintained in the complete absence of intra‐ and extracellular divalent ions, although shifted to higher osmolarities (IC50= 510 mosmol l−1). TRPM7 senses osmotic gradients rather than ionic strength and this is independent of cAMP or not affected by cytochalasin D treatment. Furthermore, the kinase‐domain deletion mutant of TRPM7 shows a similar behaviour to osmolarity as the wild‐type protein, both in the presence and absence of divalent ions. This indicates that at least part of the osmosensitivity resides in the channel domain. Physiologically, TRPM7 channels do not seem to play an active role in regulatory volume changes, but rather those volume changes modulate TRPM7 activity through changes in the cytosolic concentrations of free Mg, Mg‐nucleotides and a further unidentified factor. We conclude that TRPM7 senses osmotically induced changes primarily through molecular crowding of solutes that affect channel activity.
Maternal oxygen delivery is not related to altitude‐ and ancestry‐associated differences in human fetal growth
Authors: Zamudio Stacy , Postigo Lucrecia , Illsley Nicholas P. , Rodriguez Carmelo , Heredia Gladys , Brimacombe Michael , Echalar Lourdes , Torricos Tatiana , Tellez Wilma , Maldonado Ivan , Balanza Elfride , Alvarez Tatiana , Ameller Julio , Vargas Enrique
Published: May 2007

Fetal growth is reduced at high altitude, but the decrease is less among long‐resident populations. We hypothesized that greater maternal uteroplacental O2delivery would explain increased fetal growth in Andean nativesversusEuropean migrants to high altitude. O2delivery was measured with ultrasound, Doppler and haematological techniques. Participants (n= 180) were pregnant women of self‐professed European or Andean ancestry living at 3600 m or 400 m in Bolivia. Ancestry was quantified using ancestry‐informative single nucleotide polymorphims. The altitude‐associated decrement in birth weight was 418 g in Europeanversus236 g in Andean women (P< 0.005). Altitude was associated with decreased uterine artery diameter, volumetric blood flow and O2delivery regardless of ancestry. But the hypothesis was rejected as O2delivery was similar between ancestry groups at their respective altitudes of residence. Instead, Andean neonates were larger and heavier per unit of O2delivery, regardless of altitude (P< 0.001). European admixture among Andeans was negatively correlated with birth weight at both altitudes (P< 0.01), but admixture was not related to any of the O2transport variables. Genetically mediated differences in maternal O2delivery are thus unlikely to explain the Andean advantage in fetal growth. Of the other independent variables, only placental weight and gestational age explained significant variation in birth weight. Thus greater placental efficiency in O2and nutrient transport, and/or greater fetal efficiency in substrate utilization may contribute to ancestry‐ and altitude‐related differences in fetal growth. Uterine artery O2delivery in these pregnancies was 99 ± 3 ml min−1, ∼5‐fold greater than near‐term fetal O2consumption. Deficits in maternal O2transport in third trimester normal pregnancy are unlikely to be causally associated with variation in fetal growth.
Optical imaging of Ca2+‐evoked fluid secretion by murine nasal submucosal gland serous acinar cells
Authors: Lee Robert J. , Limberis Maria P. , Hennessy Michael F. , Wilson James M. , Foskett J. Kevin
Published: May 2007

Airway submucosal glands are sites of high expression of the cystic fibrosis transmembrane conductance regulator (CFTR) Cl− channel and contribute to fluid homeostasis in the lung. However, the molecular mechanisms of gland ion and fluid transport are poorly defined. Here, submucosal gland serous acinar cells were isolated from murine airway, identified by immunofluorescence and gene expression profiling, and used in physiological studies. Stimulation of isolated acinar cells with carbachol (CCh), histamine or ATP was associated with marked decreases in cell volume (20 ± 2% within 62 ± 5 s) that were tightly correlated with increases in cytoplasmic Ca2+ concentration ([Ca2+]i) as revealed by simultaneous DIC and fluorescent indicator dye microscopy. Simultaneous imaging of cell volume and the Cl−‐sensitive fluorophore SPQ indicated that the 20% shrinkage was associated with a fall of [Cl−]i from 65 mm to 28 mm, reflecting loss of 67% of cell Cl− content, accompanied by parallel efflux of K+. Upon agonist removal, [Ca2+]i relaxed and the cells swelled back to resting volume via a bumetanide‐sensitive Cl− influx pathway, likely to be NKCC1. Accordingly, agonist‐induced serous acinar cell shrinkage and swelling are caused by activation of solute efflux and influx pathways, respectively, and cell volume reflects the secretory state of these cells. In contrast, elevation of cAMP failed to elicit detectible volume responses, or enhance those induced by submaximal [CCh], because the magnitude of the changes were likely to be below the threshold of detection using optical imaging. Finally, when stimulated with cholinergic or cAMP agonists, cells from mice that lacked CFTR, as well as wild‐type cells treated with a CFTR inhibitor, exhibited identical rates and magnitudes of shrinkage and Cl− efflux compared with control cells. These results provide insights into the molecular mechanisms of salt and water secretion by lung submucosal glands, and they suggest that while murine submucosal gland fluid secretion in response to cholinergic stimulation can originate from CFTR‐expressing serous acinar cells, it is not dependent upon CFTR function.
Synaptic influences on rat ganglion‐cell photoreceptors
Authors: Wong Kwoon Y. , Dunn Felice A. , Graham Dustin M. , Berson David M.
Published: May 2007

The intrinsically photosensitive retinal ganglion cells (ipRGCs) provide a conduit through which rods and cones can access brain circuits mediating circadian entrainment, pupillary constriction and other non‐image‐forming visual functions. We characterized synaptic inputs to ipRGCs in rats using whole‐cell and multielectrode array recording techniques. In constant darkness all ipRGCs received spontaneous excitatory and inhibitory synaptic inputs. Light stimulation evoked in all ipRGCs both synaptically driven (‘extrinsic’) and autonomous melanopsin‐based (‘intrinsic’) responses. The extrinsic light responses were depolarizing, about 5 log units more sensitive than the intrinsic light response, and transient near threshold but sustained to brighter light. Pharmacological data showed that ON bipolar cells and amacrine cells make the most prominent direct contributions to these extrinsic light responses, whereas OFF bipolar cells make a very weak contribution. The spatial extent of the synaptically driven light responses was comparable to that of the intrinsic photoresponse, suggesting that synaptic contacts are made onto the entire dendritic field of the ipRGCs. These synaptic influences increase the sensitivity of ipRGCs to light, and also extend their temporal bandpass to higher frequencies. These extrinsic ipRGC light responses can explain some of the previously reported properties of circadian photoentrainment and other non‐image‐forming visual behaviours.
Outward stabilization of the S4 segments in domains III and IV enhances lidocaine block of sodium channels
Authors: Sheets Michael F. , Hanck Dorothy A.
Published: May 2007

The anti‐arrhythmic drug lidocaine has been shown to have a lower affinity for block of voltage‐gated sodium channels at hyperpolarized potentials compared to depolarized potentials. Concomitantly, lidocaine reduces maximum gating charge (Qmax) by 40% resulting from the complete stabilization of the S4 in domain III in an outward, depolarized position and partial stabilization of the S4 in domain IV in wild‐type Na+ channels (NaV1.5). To investigate whether the pre‐positioning of the S4 segments in these two domains in a depolarized conformation increases affinity for lidocaine block, a cysteine residue was substituted for the 3rd outermost charged residue in the S4 of domain III (R3C‐DIII) and for the 2nd outermost Arg in S4 of domain IV (R2C‐DIV) in NaV1.5. After biotinylation by exposure to extracellular MTSEA‐biotin the mutated S4s became stabilized in an outward, depolarized position. For Na+ channels containing both mutations (R3C‐DIII + R2C‐DIV) the IC50 for rested‐state lidocaine block decreased from 194 ± 15 μm in control to 28 ± 2 μm after MTSEA‐biotin modification. To determine whether an intact inactivation gate (formed by the linker between domains III and IV) was required for local anaesthetic drugs to modify Na+ channel gating currents, a Cys was substituted for the Phe in the IFM motif of the inactivation gate (ICM) and then modified by intracellular MTSET (WT‐ICMMTSET) before exposure to intracellular QX‐222, a quarternary amine. Although WT‐ICMMTSET required higher concentrations of drug to block INa compared to WT, Qmax decreased by 35% and the V1/2 shifted leftward as previously demonstrated for WT. The effect of stabilization of the S4s in domains III and IV in the absence of an intact inactivation gate on lidocaine block was determined for R3C‐DIII + ICM, R2C‐DIV + ICM and R3C‐DIII + R2C‐DIV + ICM, and compared to WT‐ICM. IC50 values were 1360 ± 430 μm, 890 ± 70 μm, 670 ± 30 μm and 1920 ± 60 μm, respectively. Thermodynamic mutant‐cycle analysis was consistent with additive (i.e. independent) contributions from stabilization of the individual S4s in R3C‐DIII + ICM and R2C‐DIV + ICM. We conclude that the positions of the S4s in domains III and IV are major determinants of the voltage dependence of lidocaine affinity.
Membrane cholesterol modulates Kv1.5 potassium channel distribution and function in rat cardiomyocytes
Authors: Abi‐Char Joëlle , Maguy Ange , Coulombe Alain , Balse Elise , Ratajczak Philippe , Samuel Jane‐Lise , Nattel Stanley , Hatem Stéphane N.
Published: May 2007

Membrane lipid composition is a major determinant of cell excitability. In this study, we assessed the role of membrane cholesterol composition in the distribution and function of Kv1.5‐based channels in rat cardiac membranes. In isolated rat atrial myocytes, the application of methyl‐β‐cyclodextrin (MCD), an agent that depletes membrane cholesterol, caused a delayed increase in the Kv1.5‐based sustained component, Ikur, which reached steady state in ∼7 min. This effect was prevented by preloading the MCD with cholesterol. MCD‐increased current was inhibited by low 4‐aminopyridine concentration. Neonatal rat cardiomyocytes transfected with Green Fluorescent Protein (GFP)‐tagged Kv1.5 channels showed a large ultrarapid delayed‐rectifier current (IKur), which was also stimulated by MCD. In atrial cryosections, Kv1.5 channels were mainly located at the intercalated disc, whereas caveolin‐3 predominated at the cell periphery. A small portion of Kv1.5 floated in the low‐density fractions of step sucrose‐gradient preparations. In live neonatal cardiomyocytes, GFP‐tagged Kv1.5 channels were predominantly organized in clusters at the basal plasma membrane. MCD caused reorganization of Kv1.5 subunits into larger clusters that redistributed throughout the plasma membrane. The MCD effect on clusters was sizable 7 min after its application. We conclude that Kv1.5 subunits are concentrated in cholesterol‐enriched membrane microdomains distinct from caveolae, and that redistribution of Kv1.5 subunits by depletion of membrane cholesterol increases their current‐carrying capacity.
Radio-Frequency Ablation in a Realistic Reconstructed Hepatic Tissue
Authors: Hariharan Prasanna , Chang Isaac , Myers Matthew R. , Banerjee Rupak K.
Published: May 2007

This study uses a reconstructed vascular geometry to evaluate the thermal response of tissue during a three-dimensional radiofrequency (rf) tumor ablation. MRI images of a sectioned liver tissue containing arterial vessels are processed and converted into a finite-element mesh. A rf heat source in the form of a spherically symmetric Gaussian distribution, fit from a previously computed profile, is employed. Convective cooling within large blood vessels is treated using direct physical modeling of the heat and momentum transfer within the vessel. Calculations of temperature rise and thermal dose are performed for transient rf procedures in cases where the tumor is located at three different locations near the bifurcation point of a reconstructed artery. Results demonstrate a significant dependence of tissue temperature profile on the reconstructed vasculature and the tumor location. Heat convection through the arteries reduced the steady-state temperature rise, relative to the no-flow case, by up to 70% in the targeted volume. Blood flow also reduced the thermal dose value, which quantifies the extent of cell damage, from ∼3600min, for the no-flow condition, to 10min for basal flow (13.8cm∕s). Reduction of thermal dose below the threshold value of 240min indicates ablation procedures that may inadequately elevate the temperature in some regions, thereby permitting possible tumor recursion. These variations are caused by vasculature tortuosity that are patient specific and can be captured only by the reconstruction of the realistic geometry.
Numerical Stability Analysis of a Forced Two-D.O.F. Oscillator With Bilinear Damping
Authors: Szabó Zsolt , Lukács Attila
Published: May 2007

The current paper investigates the nonlinear stationary oscillations of a quarter vehicle model with two degrees of freedom subjected to a vertical road excitation. The damping of the wheel suspension has a bilinear characteristic, so that the damping strength is larger during compression than during restitution of the damper. For the optimization of the damping behavior the peak-to-peak swings have to be as small as possible. The unevenness of the road was approximated by filtered white noise which was modelled numerically using pseudorandom sequences. The first order form of the governing equations was transformed to hyperspherical representation. The stability was determined according to the largest Liapunov exponents obtained from the numerical simulation. For a chosen parameter range stability charts were constructed both in the stochastic and harmonic case (for comparison).
Reconstruction and Separation in a Semi-Free Field by Using the Distributed Source Boundary Point Method-Based Nearfield Acoustic Holography
Authors: Bi C. X. , Chen X. Z. , Zhou R. , Chen J.
Published: May 2007

In a semi-free field, the acoustic field is composed of two components: the direct sound and the reflected sound. Because it is difficult to separate the direct sound from the acoustic field, conventional nearfield acoustic holography (NAH) methods cannot reconstruct an acoustic source and predict the acoustic field directly. Through utilization of the distributed source boundary point method (DSBPM)-based NAH, a treatment method for a semi-free field is proposed. In the method, the source in a semi-free field can be reconstructed correctly, and the acoustic field can be predicted and separated. An experiment on a speaker in a semi-anechoic chamber is carried out to verify the proposed method. By comparing the reconstructed and predicted results in DSBPM-based NAH with and without the proposed method, the proposed method is validated. The disadvantages of NAH without any treatment method in a semi-free field are demonstrated.
Vibrations of Complete Spherical Shells With Imperfections
Authors: Duffey Thomas A. , Pepin Jason E. , Robertson Amy N. , Steinzig Michael L. , Coleman Kimberly
Published: May 2007

Numerous theoretical investigations on the natural frequencies for complete spherical shells have been reported over the past four decades. However, attempts at correlating the theoretical results with either experimental or simulated results (both for axisymmetric and nonaxisymmetric modes of vibration) are almost completely lacking. In this paper, natural frequencies and mode shapes obtained from axisymmetric and nonaxisymmetric theories of vibration of complete spherical shells and from finite element computer simulations of the vibrations, with and without geometrical imperfections, are presented. Modal tests reported elsewhere on commercially available, thin spherical marine floats (with imperfections) are then utilized as a basis for comparison of frequencies to both the theoretical and numerical results. Because of the imperfections present, “splitting” of frequencies of nonaxisymmetric modes is anticipated. The presence of this frequency splitting phenomenon is demonstrated. In addition, results of a “whole field” measurement on one of the imperfect shells using dynamic holography are presented.
Surface Friction Guiding for Reduced High-Frequency Lateral Vibration of Moving Media
Authors: Kartik V. , Wickert J. A.
Published: May 2007

The free and forced vibration of a moving medium is examined in an application where distributed friction guiding is used to control lateral position passively. Subambient pressure features formed in the guides intentionally modify the naturally occurring self-pressurized air bearing and increase the contact force between the medium and the guide’s surface. These features increase friction to a level beyond that achievable based on the nominal wrap pressure. The moving medium is modeled as a beam that is transported over frictional regions and subjected to prescribed boundary disturbances arising from runout of a supply or take-up roll. For axial transport at a speed that is high compared to the velocity of lateral vibration, Coulomb friction between the guides and the moving medium can be well approximated by a derived expression for equivalent viscous damping. The equation of motion is developed for the cases of a single cylindrical guide and of a multiplicity of guides having arbitrary placement. The level of equivalent damping for each mode decreases with transport speed, and critical speeds exist where each vibration mode transitions between the overdamped and underdamped regimes. Parameter studies in the contact pressure, transport speed, and guide geometry identify preferred design configurations for maximizing dissipation in particular modes and for attenuating high-frequency response.
A New Software Approach for the Simulation of Multibody Dynamics
Authors: Vlasenko Dmitry , Kasper Roland
Published: May 2007

This paper introduces a new modular software approach combining symbolical and numerical methods for the simulation of the dynamics of mechanical systems. It is based on an exact, noniterative object-oriented algorithm, which is applicable to mechanisms with any joint type and any topology, including branches and kinematic loops. The simulation of big well-partitioned systems has complexity O(N), where N is the total number of simulated bodies. A new design software Virtual System Designer (VSD) integrates this method with the three-dimensional computer aided design tool Autodesk Inventor, which minimizes the cost of the development of models and the training of design engineers. The most time-expensive routine of the simulation process in VSD is the calculation of the accelerations of each body, which needs to find the roots of matrix equations. Accounting for the sparsity of matrices can significantly improve the numerical efficiency of the routine. The preprocessing module, developed using Maple software, performs the symbolic simplification of the matrix multiplication’s and QR decomposition’s procedures. The new coordinate projection method is demonstrated. The results of the simulation of the dynamics of a double insulator chain example show the method’s stability and effectiveness.
A Theoretical and Experimental Investigation of Lateral Deformations in a Unilateral External Fixator
Authors: Ün Kerem , Akçalı İbrahim D. , Gülşen Mahir
Published: May 2007

The objective of this work is to set up, validate, and analyze a theoretical model of an external fixator for its deformation characteristics in order to draw reliable conclusions relevant to the design and effective clinical implementation of such medical devices. External fixators are mechanical devices widely used in the treatment of fractured bones and correction of limb deformities. Lateral deformation at the fracture site is known to delay bone healing, and investigation of lateral deformation characteristics of such devices experiencing forces acting perpendicular to the bone axis is important from the standpoint of their design as well as their clinical effectiveness. A mathematical model of a three-dimensional (3D) unilateral fixator with multipin fragment attachments has been developed using Castigliano’s method. The relative lateral deformations of the fragment ends at the fracture site induced by loads applied perpendicular to bone axes are calculated with the model. The model has been subjected to experimental verification for a uniplanar unilateral external fixator under comparable conditions with the theory. It has been found out that the effects of fixator size, shape, and geometry on the level of relative lateral displacement of the fracture site are similar in both the theoretical and experimental models. Stiffness is a maximum if the force is applied in the same plane as the proximal pin plane. Placing the distal pin group at a 90deg position relative to the proximal pin plane has been observed to increase the stiffness about 10%. In loading directions perpendicular to proximal the pin plane, stiffness is minimum. The angle difference between the load direction and the resulting displacement direction follows a sinusoidal pattern with an amplitude of 10deg for loading angles in the 0–180deg range. Selecting the distance of proximal pins to the fracture site smaller than the distance of distal pins to the fracture site has been found to decrease relative lateral deformation. The model and the experiment have simultaneously demonstrated that lower values of effective pin lengths and higher values of pin connector lengths lead to higher stiffness. Increasing the number of pins also contributes to the higher values of fixator stiffness.
Flexible Prosthetic Vein Valve
Authors: Sathe Rahul D. , Ku David N.
Published: May 2007

Over 7 million Americans suffer from chronic venous insufficiency (CVI), a disease that affects the venous system of the lower extremities. Problems associated with CVI include ulcerations, bleeding, swelling, and varicose veins, as well as deep vein thrombosis and pulmonary embolism. The presence of CVI is the result of incompetent, or malfunctioning, one-way vein valves in leg veins. There are few effective clinical therapies for treating CVI and there are currently no prosthetic vein valves commercially available. The purpose of this study was to define clinically relevant design requirements, develop functional tests for assessing a prosthetic vein valve, and design and fabricate a functional prosthetic vein valve for eventual clinical use. Engineering design methods were used to develop the valve, building a product based on well-defined consumer needs and design specifications. Emphasis was placed on creating a valve with potential clinical functionality. This clinical functionality was distilled into three major design criteria: that the valve (1) withstand backpressure of 300mmHg with less than 1.0mL∕min of leakage; (2) open with distal pressure gradients less than 5mmHg; and (3) meet criteria 1 and 2 after 500,000cycles of opening and closing. Hydrostatic testing was conducted to measure the opening pressure and reflux leak rate of the valve. Cyclic life functionality was assessed using a cyclic flow loop simulating physiologic conditions of cyclic flow and pressure found in leg veins. The valve opened with a pressure of 2.6mmHg±0.7mmHg, which matches physiologic vein valve function. The valve also withstood 300mmHg of backpressure with less than 0.5mL∕min of leakage, and maintained this performance even after 508,000cycles of opening and closing in simulated physiologic conditions. The valve’s burst pressure was a minimum of 530mmHg±10mmHg, six times greater than physiologic pressure natural vein valves experience. The valve continued to function well in an environment of vein-like tube expansion. The newly designed bi-leaflet prosthetic valve is comprised of a flexible, biocompatible material. Bench test results have shown that the valve is hydrodynamically functional and meets the mechanical design criteria for backpressure competency and opening pressure after 500,000cycles. Finally, the valve can be manufactured easily with low cost.
Locating the Two Black Holes in NGC 6240
Authors: Max Claire E. , Canalizo Gabriela , de Vries Willem H.
Published: May 2007

Mergers play an important role in galaxy evolution and are key to understanding the correlation between central–black hole mass and host-galaxy properties. We used the new technology of adaptive optics at the Keck II telescope to observe NGC 6240, a merger between two disk galaxies. Our high-resolution near-infrared images, combined with radio and x-ray positions, revealed the location and environment of two central supermassive black holes. Each is at the center of a rotating stellar disk, surrounded by a cloud of young star clusters. The brightest of these young clusters lie in the plane of each disk, but surprisingly are seen only on the disks' receding side.
Response to Comments on "A Centrosome-Independent Role for γ-TuRC Proteins in the Spindle Assembly Checkpoint"
Authors: Müller Hannah , Fogeron Marie-Laure , Lehmann Verena , Lehrach Hans , Lange Bodo M. H.
Published: May 2007

Weaver and Cleveland and Taylor
et al
. contend that our data on the involvement of the γ-tubulin ring complex (γ-TuRC) in the spindle assembly checkpoint (SAC) can be fully explained by kinetochore-derived checkpoint signaling. We maintain that (i) the interactions of γ-TuRC with Cdc20 and BubR1, and (ii) the activation of SAC by γ-TuRC depletion, in addition to the abrogation of kinetochore-microtubule interactions, argue for a more complex mechanism of SAC signaling.
Far-Field Optical Nanoscopy
Authors: Hell Stefan W.
Published: May 2007

In 1873, Ernst Abbe discovered what was to become a well-known paradigm: the inability of a lens-based optical microscope to discern details that are closer together than half of the wavelength of light. However, for its most popular imaging mode, fluorescence microscopy, the diffraction barrier is crumbling. Here, I discuss the physical concepts that have pushed fluorescence microscopy to the nanoscale, once the prerogative of electron and scanning probe microscopes. Initial applications indicate that emergent far-field optical nanoscopy will have a strong impact in the life sciences and in other areas benefiting from nanoscale visualization.
Response to Comment on "Dispersal Limitations Matter for Microbial Morphospecies"
Authors: Telford Richard J. , Vandvik Vigdis , Birks H. J. B.
Published: May 2007

Pither argues that the relationship we found between regional species-richness maxima and modal lake pH is expected because both values are constrained by the regional pH range and therefore cannot be interpreted as a signal of regional metacommunity dynamics. However, the null model he uses sets inappropriate parameters, generating unrealistic simulated data. We confirm our previous conclusions using a more appropriate null model.
Stress Control of Deep Rift Intrusion at Mauna Loa Volcano, Hawaii
Authors: Amelung Falk , Yun Sang-Ho , Walter Thomas R. , Segall Paul , Kim Sang-Wan
Published: May 2007

Mauna Loa volcano, Hawaii, deforms by a combination of shallow dike intrusions in the rift zones and earthquakes along the base of the volcano, but it is not known how the spreading is accommodated in the lower part of the volcanic edifice. We present evidence from interferometric synthetic aperture radar data for secular inflation of a dike-like magma body at intermediate depth in the southwest rift zone during 2002 to 2005. Magma accumulation occurred in a section of the rift zone that was unclamped by previous dikes and earthquakes, suggesting that stress transfer plays an important role in controlling subsurface magma accumulation.
Molecular Basis of the Shish-Kebab Morphology in Polymer Crystallization
Authors: Kimata Shuichi , Sakurai Takashi , Nozue Yoshinobu , Kasahara Tatsuya , Yamaguchi Noboru , Karino Takeshi , Shibayama Mitsuhiro , Kornfield Julia A.
Published: May 2007

In the rich and long-standing literature on the flow-induced formation of oriented precursors to polymer crystallization, it is often asserted that the longest, most extended chains are the dominant molecular species in the “shish” of the “shish-kebab” formation. We performed a critical examination of this widely held view, using deuterium labeling to distinguish different chain lengths within an overall distribution. Small-angle neutron-scattering patterns of the differently labeled materials showed that long chains are not overrepresented in the shish relative to their concentration in the material as a whole. We observed that the longest chains play a catalytic role, recruiting other chains adjacent to them into formation of the shish.
Bose-Einstein Condensation of Microcavity Polaritons in a Trap
Authors: Balili R. , Hartwell V. , Snoke D. , Pfeiffer L. , West K.
Published: May 2007

We have created polaritons in a harmonic potential trap analogous to atoms in optical traps. The trap can be loaded by creating polaritons 50 micrometers from its center that are allowed to drift into the trap. When the density of polaritons exceeds a critical threshold, we observe a number of signatures of Bose-Einstein condensation: spectral and spatial narrowing, a peak at zero momentum in the momentum distribution, first-order coherence, and spontaneous linear polarization of the light emission. The polaritons, which are eigenstates of the light-matter system in a microcavity, remain in the strong coupling regime while going through this dynamical phase transition.
More Means of Regulating Genes
Authors: Corpet Armelle , Almouzni Geneviève
Published: May 2007

Epigenetics
.
C. David Allis, Thomas Jenuwein, and Danny Reinberg, Eds.
. Cold Spring Harbor Laboratory Press, Cold Spring Harbor, NY, 2007. 512 pp. $150, £85. ISBN 9780879697242.

The contributors offer an up-to-date survey of perspectives on the mechanisms and consequences of epigenetics.
The Structure of Ferrihydrite, a Nanocrystalline Material
Authors: Michel F. Marc , Ehm Lars , Antao Sytle M. , Lee Peter L. , Chupas Peter J. , Liu Gang , Strongin Daniel R. , Schoonen Martin A. A. , Phillips Brian L. , Parise John B.
Published: May 2007

Despite the ubiquity of ferrihydrite in natural sediments and its importance as an industrial sorbent, the nanocrystallinity of this iron oxyhydroxide has hampered accurate structure determination by traditional methods that rely on long-range order. We uncovered the atomic arrangement by real-space modeling of the pair distribution function (PDF) derived from direct Fourier transformation of the total x-ray scattering. The PDF for ferrihydrite synthesized with the use of different routes is consistent with a single phase (hexagonal space group
P
6
3
mc
;
a
= ∼5.95 angstroms,
c
= ∼9.06 angstroms). In its ideal form, this structure contains 20% tetrahedrally and 80% octahedrally coordinated iron and has a basic structural motif closely related to the Baker-Figgis δ-Keggin cluster. Real-space fitting indicates structural relaxation with decreasing particle size and also suggests that second-order effects such as internal strain, stacking faults, and particle shape contribute to the PDFs.
Diversity Paradoxes
Authors: Tetlock Philip E.
Published: May 2007

The Difference
. How the Power of Diversity Creates Better Groups, Firms, Schools, and Societies.
By Scott E. Page
. Princeton University Press, Princeton, NJ, 2007. 448 pp. $27.95, £17.95. ISBN 9780691128382.

From a consideration of how humans think in groups, Page argues for the advantages of diversity.
Effect of static stretching of muscles surrounding the knee on knee joint position sense
Authors: Ghaffarinejad Farahnaz , Taghizadeh Shohreh , Mohammadi Farshid
Published: May 2007

Background:

Muscle stretching is widely used in sport training and in rehabilitation. Considering the important contribution of joint position sense (JPS) to knee joint stability and function, it is legitimate to question if stretching might alter the knee JPS.

Objective:

To evaluate if a stretch regimen consisting of three 30 s stretches alters the knee JPS.

Design and setting:

A blinded, randomised design with a washout time of 24 h was used.

Subjects:

39 healthy students (21 women, 18 men) volunteered to participate in this study.

Methods and main outcome measures:

JPS was estimated by the ability to reproduce the two target positions (20° and 45° of flexion) in the dominant knee. The absolute angular error (AAE) was defined as the absolute difference between the target angle and the subject perceived angle of knee flexion. AAE values were measured before and immediately after the static stretch. Measurements were repeated three times. The static stretch comprised a 30 s stretch followed by a 30 s pause, three times for each muscle.

Results:

The AAE decreased significantly after the stretching protocols for quadriceps (3.5 (1.3) vs 0.7 (2.4); p<0.001), hamstring (3.6 (2.2) vs 1.6 (3.1); p = 0.016) and adductors (3.7 (2.8) vs 1.7 (2.4); p = 0.016) in 45° of flexion, but no differences were found for values of the gastrocnemius and popliteus muscles in this angle and for the values of all muscles in 20° of flexion (p>0.05).

Conclusion:

The accuracy of the knee JPS in 45° of flexion is improved subsequent to a static stretch regimen of quadriceps, hamstring and adductors in healthy subjects.
Salbutamol exhibits androgenic activity in vitro
Authors: von Bueren André O , Ma Risheng , Schlumpf Margret , Lichtensteiger Walter
Published: May 2007

Background:

Salbutamol has been shown to mediate anabolic effects after intravenous administration. However, the mechanism responsible for the anabolic actions of salbutamol remains unknown.

Aim:

To investigate the potential mechanism by which salbutamol mediates anabolic effects in vitro.

Methods:

The potential androgenic activity of salbutamol was investigated in vitro by the A-Screen assay that measures androgen-dependent inhibition of proliferation of the androgen receptor (AR)-positive human mammary carcinoma cell line, MCF7-AR1.

Results:

The assay was validated with three known androgens; methyltrienolone (R1881), 5α-dihydrotestosterone (DHT) and danazol. IC50values of R1881, DHT and danazol, 4.41×10−11, 4.44×10−11and 1.08×10−8M, respectively, were in the ranges known from earlier studies. Our results demonstrate that salbutamol exhibits androgenic activity, with an IC50value of 8.93×10−6M. Anti-estrogenic or cytotoxic effects, which might have interfered with the assay, were excluded by additional experiments on wild-type MCF7 and MCF7-AR1 cells, respectively.

Conclusion:

These data indicate that salbutamol exerts anabolic effects through androgen receptor agonistic activity in vitro.
Conjugated linoleic acid increases skeletal muscle ceramide content and decreases insulin sensitivity in overweight, non-diabetic humans
Authors: Thrush A. Brianne , Chabowski Adrian , Heigenhauser George J. , McBride Brian W. , Or-Rashid Mamun , Dyck David J.
Published: May 2007

The effect of conjugated linoleic acid (CLA), a popular weight-loss supplement, on insulin sensitivity in humans is controversial and has notbeen extensively studied. To date no studies have examined the effects of CLA supplementation on human skeletal muscle metabolism or lipid content. It is also unknown whether CLA accumulates in human skeletal muscle with supplementation. In the present study, 9 overweight, non-diabetic individuals received 4 g/d of mixed CLA isomers in the form of 1 g supplements, for 12 weeks. CLA isomers significantly increased in both plasma and skeletal muscle following supplementation. Skeletal muscle ceramide content was also significantly increased, although there was no consistent change in muscle diacylglycerol or triacylglycerol content. Insulin sensitivity was significantly decreased (p ≤ 0.05) following CLA supplementation, with a significant increase in glucose and insulin area under the curve during an oral glucose tolerance test (p ≤ 0.005). The protein content of PPARα, for which CLA is a potent ligand, was unchanged following supplementation. Accordingly, there was no change in markers of muscle oxidative capacity. In conclusion, mixed-isomer CLA supplementation in overweight non-diabetic humans results in the accumulation of CLA and ceramide in skeletal muscle, and decreases insulin sensitivity.
The influence of velocity of stretch–shortening contractions on muscle performance during chronic exposure: age effects
Authors: Cutlip Robert G. , Baker Brent A. , Geronilla Ken B. , Kashon Michael L. , Wu John Z.
Published: May 2007

Aging increases injury susceptibility and impairs the ability to adapt to repetitive exposures of mechanical loading. The objective of this research was to investigate if movement velocity affects muscle response to a chronic administration of stretch–shortening cycles (SSCs) differently in young vs. old rats. Dorsiflexor muscles of old (30 months, n = 5) and young rats (12 weeks, n = 6) were exposed 3 times/week for 4.5 weeks to a protocol of 80 maximal SSCs per exposure in vivo. Skeletal muscle response was characterized by high- (500°/s) and low- (60°/s) velocity dynamic performance, which was evaluated using peak eccentric force, isometric pre-stretch force, eccentric force enhancement above the isometric pre-stretch force, negative work, and positive work. The performance of the young and old groups was not statistically different at the start of the exposure. By the end of the exposure, however, a statistical difference was noted—performance increased significantly in the young animals and decreased significantly in the old animals. The SSC velocity had a profound effect on muscle response. The young animals’ high- and low-velocity performances increased during the chronic exposure period, whereas the old animals’ performances declined. High-velocity performance increased more than low-velocity performance in young animals. In contrast, old animals suffered the most loss in high-velocity performance over the chronic exposure period. A chronic exposure of SSCs results in a significant performance increase in young animals, and a significant performance decrease in old animals. These differences are more profound during high-velocity movements. These findings suggest that age may impair the ability of skeletal muscle to adapt to repetitive mechanical loading, particularly during high-velocity movements.
Neither gender nor menstrual cycle phase influences exercise-induced lymphocyte apoptosis in untrained subjects
Authors: Navalta James W. , Sedlock Darlene A. , Park Kyung-Shin , McFarlin Brian K.
Published: May 2007

Lymphocyte apoptosis increases following maximal exercise. Estrogen hormones (E2) have been shown to protect lymphocytes from apoptosis in vitro, but it is unknown whether they can attenuate the apoptotic response to maximal exercise. The purpose of this study was to examine the effect of menstrual cycle variation on exercise-induced lymphocyte apoptosis in humans following exercise. Untrained healthy young men and regularly menstruating women not using hormonal contraceptives volunteered for the study. Women performed a maximal effort treadmill test for VO2 max once in the follicular phase (FOL) and once in the mid-luteal phase (ML) of their cycles. Men completed two VO2 max tests with periods of time between tests matched to those of the female subjects. Blood was collected before (PRE) and immediately after exercise (POST), and analyzed for apoptotic lymphocytes and estradiol. E2 concentrations in women were significantly greater during ML versus during FOL, both PRE and POST (p < 0.0001). The percent of exercise-induced lymphocyte apoptosis was similar between women (23.2% ± 1.0%) and men (21.5% ± 0.4%). In women, the apoptotic response to maximal exercise was similar regardless of menstrual cycle phase (FOL = 23.7% ± 0.9%, ML = 22.7% ± 1.1%). Although elevated female sex hormones in vitro may exert anti-apoptotic effects, these data suggest that in vivo concentrations confer no protection to lymphocytes during exhaustive exercise.
The effect of exercise, training, and inactivity on insulin sensitivity in diabetics and their relatives: what is new?
Authors: Østergård Torben , Jessen Niels , Schmitz Ole , Mandarino Lawrence J.
Published: May 2007

Insulin resistance is a hallmark characteristic of type 2 diabetes. However, in healthy first-degree relatives of type 2 diabetics, insulin resistance is often present years before glucose intolerance or diabetes becomes clinically manifest. The mechanisms of insulin resistance involve conditions leading to an increased supply of fatty acids (e.g., high energy intake, obesity) and conditions in which the degradation/oxidation of muscular fatty acids is impaired. Several large-scale studies have documented the fact that increased physical activity can reduce or at least postpone the development of type 2 diabetes, and low physical fitness is a clear independent risk factor for the development of type 2 diabetes. The mechanisms responsible for the improvement in insulin sensitivity after exercise training have been studied extensively, but are not fully understood. This review focuses on insulin resistance in skeletal muscle and, in particular, its relation to changes in aerobic fitness in type 2 diabetics and their first-degree relatives.
The behavioural response of lactating Weddell seals (Leptonychotes weddellii) to over-snow vehicles: a case study
Authors: van Polanen Petel T.D. , Giese M.A. , Wotherspoon S. , Hindell M.A.
Published: May 2007

Over-snow vehicles are used extensively at Antarctic scientific research stations. Adult female Weddell seals ( Leptonychotes weddellii (Lesson, 1826)) also utilise the fast-ice and are therefore often exposed to vehicular activity, with the potential of affecting their behaviour. Guidelines for vehicular travel have been developed to minimise disturbance to Antarctic wildlife; however, these guidelines have not yet been scientifically tested. To examine the efficiency and sensitivity of existing guidelines used within the Australian Antarctic Territory (AAT), we conducted drive-by experiments of two types of over-snow vehicles. The results of these experiments showed that the probability of a lactating Weddell seal looking at the vehicles and the duration of the seals’ looking at the vehicles were dependent on the distance between vehicles and seals, the position of the pups in relation to its mother, and the distance the adult female was from the water. Although the seals apparently perceived the vehicles to be a threat, no seals fled in response to vehicle activity. We propose that the existing guidelines used in the AAT could be amended to increase separation distances between vehicles and breeding Weddell seals if the goal of management is to ensure that Weddell seal behaviour is unaffected by vehicle travel.