Estrogen plus estrogen receptor antagonists alter mineral production by osteoblasts in vitro.

In early postmenopausal women, estrogen withdrawal is associated with increased bone turnover leading to bone loss and increased risk of fracture. Recent studies have suggested that the remaining bone tissue is significantly stronger, stiffer and has an increased tissue-level mineral content. Such changes may occur to compensate for bone loss or as a direct result of estrogen deficiency. To date many details of the physiology of osteoblastic cells during estrogen deficiency are vague. In this study we test the hypothesis that osteoblastic matrix mineralisation is altered at the onset of estrogen deficiency. In vitro cell culture experiments were carried out up to 28 days to compare the mineral production of MC3T3-E1 osteoblastic cells subject to estrogen deficiency (fulvestrant), enhanced estrogen supplementation (17-β-estradiol) or a combination of both. Mineralisation was detected using von Kossa staining and was quantified with alizarin red absorbance readings. The expression of osteocalcin and osteopontin proteins, markers of osteoblast differentiation and mineralisation, was monitored using immunohistochemistry. Our results demonstrate that estrogen enhancement improves matrix mineralisation by MC3T3 cells in vitro. Furthermore this study found a significant reduction in the level of mineralisation when cells were treated with a combination of estrogen and fulvestrant. In an estrogen deficient environment mineralisation by osteoblastic cells was not altered. These findings suggest that altered tissue mineralisation following estrogen deficiency is not a direct result of estrogen deficiency on osteoblasts. Rather, we propose that altered tissue mineralisation may be a compensatory mechanism by bone to counter bone loss and reduced strength

A Large Atom Number Metastable Helium Bose-Einstein Condensate

We have produced a Bose-Einstein condensate of metastable helium (4He*) containing over 1.5x10^7 atoms, which is a factor of 25 higher than previously achieved. The improved starting conditions for evaporative cooling are obtained by applying one-dimensional Doppler cooling inside a magnetic trap. The same technique is successfully used to cool the spin-polarized fermionic isotope (3He*), for which thermalizing collisions are highly suppressed. Our detection techniques include absorption imaging, time-of-flight measurements on a microchannel plate detector and ion counting to monitor the formation and decay of the condensate.Comment: 4 pages, 3 figures (changed content

Seasonal and Spatial Patterns Differ Between Intracellular and Extracellular Antibiotic Resistance Genes in Urban Stormwater Runoff

Antibiotic resistance is a public health threat that is exacerbated by the dispersion of antibiotic resistance genes (ARGs) into aquatic environments. Urban stormwater runoff has been recognized as a source of and a mechanism by which intracellular ARGs (iARGs) can be transported into receiving environments. The prevalence and behavior of extracellular ARGs (eARGs) in stormwater, however, has yet to be considered. This study quantified four iARGs and eARGs under baseflow and stormflow conditions. Urban stormwater runoff was found to be a source of all the ARGs examined, with the absolute concentration of all iARGs and two eARGs (ermF and tetC) increasing significantly (p \u3c 0.05) between baseflow and stormflow. The occurrence of iARGs and eARGs in stormwater runoff was also investigated across three seasons to differentiate temporal trends. All eARGs were found to be most abundant in the fall, while the iARGs did not display a consistent seasonal trend. Following, spatial patterns of the ARGs were elucidated by targeting four sampling locations, including direct runoff from a curbside storm inlet and a stormwater outfall, and two receiving environments, the Menomonee River and Lake Michigan. Stormwater was found to have the largest impact, in terms of the percent increase in ARG concentrations between baseflow and stormflow, on the outfall location where on average the iARGs and eARGs increased 16% and 12.3%, respectively. The variability in seasonal and spatial trends between the iARGs and eARGs suggests a difference in sources and transport mechanisms of the ARGs into the environment. Moreover, the results of this study revealed that eARGs are relevant contaminants to consider when determining the threat of antibiotic resistance originating from stormwater runoff

Vibrational Coupling in Conjugated π Systems with a view to Optimization of Fluorescence Yield through Phonon Confinement

A series of π conjugated systems were studied by absorption, photoluminescence and vibrational spectroscopy. As is common for these systems, a linear relationship between the positioning of the absorption and photoluminescence maxima plotted against inverse conjugation length is observed. The relationships are in good agreement with the simple particle in a box method, one of the earliest descriptions of the properties of one-dimensional organic molecules. In addition to the electronic transition energies, it was observed that the Stokes shift also exhibited a well-defined relationship with increasing conjugation length, implying a correlation between the electron-vibrational coupling and chain length. This correlation is further examined using Raman spectroscopy, whereby the integrated Raman scattering is seen to behave superlinearly with chain length. There is a clear indication that the vibrational activity and thus nonradiative decay processes are controllable through molecular structure. The correlations between the Stokes energies and the vibrational structure are also observed in a selection of PPV based polymers and a clear trend of increasing luminescence efficiency with decreasing vibrational activity and Stokes shift is observable. The implications of such structure property relationships in terms of materials design are discussed

Implementation of Time-Delay Interferometry for LISA

We discuss the baseline optical configuration for the Laser Interferometer Space Antenna (LISA) mission, in which the lasers are not free-running, but rather one of them is used as the main frequency reference generator (the {\it master}) and the remaining five as {\it slaves}, these being phase-locked to the master (the {\it master-slave configuration}). Under the condition that the frequency fluctuations due to the optical transponders can be made negligible with respect to the secondary LISA noise sources (mainly proof-mass and shot noises), we show that the entire space of interferometric combinations LISA can generate when operated with six independent lasers (the {\it one-way method}) can also be constructed with the {\it master-slave} system design. The corresponding hardware trade-off analysis for these two optical designs is presented, which indicates that the two sets of systems needed for implementing the {\it one-way method}, and the {\it master-slave configuration}, are essentially identical. Either operational mode could therefore be implemented without major implications on the hardware configuration. We then.......Comment: 39 pages, 6 figures, 2 table

Construction of a deep shaft for Crossrail

An 8·2 m diameter, 37·5 m deep shaft has been successfully constructed from within the basement of a new development, Moorhouse, near Moorgate in the City of London. Programme constraints led to the shaft being constructed after completion of the foundations, basements and most of the superstructure for the development. At its closest point the shaft is less than 2 m from the large-diameter piles that support Moorhouse, and the presence of these foundations placed tight constraints on acceptable ground movements associated with construction of the shaft. The depth of the shaft is such that it penetrates through stiff London Clay and is founded at the bottom of the Lambeth Group. The paper describes the contingency measures to deal with potentially difficult ground conditions, including the water-bearing layers of the Lambeth Group. The construction processes included a complex temporary works dewatering system around the shaft, with the option to carry out additional dewatering from within the shaft during excavation. Provision was also made for radial grouting to ‘restress’ the ground, to prevent long-term settlement of the Moorhouse piles, should the need arise. The success of the project was due, in no small part, to the detailed planning and consideration of contingency measures to deal with perceived risk

Fluid Induced Particle Size Segregation in Sheared Granular Assemblies

We perform a two-dimensional molecular-dynamics study of a model for sheared bidisperse granular systems under conditions of simple shear and Poiseuille flow. We propose a mechanism for particle-size segregation based on the observation that segregation occurs if the viscous length scale introduced by a liquid in the system is smaller than of the order of the particle size. We show that the ratio of shear rate to viscosity must be small if one wants to find size segregation. In this case the particles in the system arrange themselves in bands of big and small particles oriented along the direction of the flow. Similarly, in Poiseuille flow we find the formation of particle bands. Here, in addition, the variety of time scales in the flow leads to an aggregation of particles in the zones of low shear rate and can suppress size segregation in these regions. The results have been verified against simulations using a full Navier-Stokes description for the liquid.Comment: 11 pages, REVTEX format, ps figures compressed uuencoded separately or by e-mail from [email protected]. A postscript version of the paper will be available from http://www.ica1.uni-stuttgart.de/local/WWW/papers/papers.htm

Variable stars in the Open Cluster M11 (NGC 6705)

V-band time-series CCD photometric observations of the intermediate-age open cluster M11 were performed to search for variable stars. Using these time-series data, we carefully examined light variations of all stars in the observing field. A total of 82 variable stars were discovered, of which 39 stars had been detected recently by Hargis et al. (2005). On the basis of observational properties such as variable period, light curve shape, and position on a color-magnitude diagram, we classified their variable types as 11 delta Scuti-type pulsating stars, 2 gamma Doradus-type pulsating stars, 40 W UMa-type contact eclipsing binaries, 13 Algol-type detached eclipsing binaries, and 16 eclipsing binaries with long period. Cluster membership for each variable star was deduced from the previous proper motion results (McNamara et al. 1977) and position on the color-magnitude diagram. Many pulsating stars and eclipsing binaries in the region of M11 are probable members of the cluster.Comment: 23 pages, 9 figures, 3 tables, and accepted for publication in PAS