Planar micromachined glass cantilevers utilising integrated Bragg Fabry-Perot cavities

Here we demonstrate a glass cantilever based on a unique micromachining and etching approach, combined with UV written Bragg gratings. We shall also discuss the increase in sensitivity by using two Bragg gratings to form Fabry-Pérot cavity. Cantilevers are in ultra sensitive force sensors used in applications such as Atomic Force Microscopy, mass sensing and acoustic transducers

Fibrinogen E fragment selectively disrupts the vasculature and inhibits the growth of tumours in a syngeneic murine model

We recently demonstrated that a fragment of human fibrinogen, fibrinogen E fragment, inhibits the migration and differentiation of human endothelial cells in vitro. Here we show that it exerts similar effects on murine endothelial cells in vitro, and selectively disrupts tumour endothelium in vivo, causing widespread intravascular thrombosis and retarding the growth of CT26 tumours in a syngeneic murine model

Direct grating writing: single-step Bragg grating and waveguide fabrication for telecommunications and sensing applications

Direct Grating Writing (DGW) has been developed over the past decade as a means of rapidly prototyping waveguides with integrated Bragg grating structures in silica-on-silicon substrates [1]. The technique allows complicated waveguide structures and Bragg grating arrays to be fabricated and characterised in house

Power-efficiency enhanced thermally tunable Bragg grating for silica-on-silicon photonics

A thermally tunable Bragg grating device has been fabricated in a silica-on-silicon integrated optical chip, incorporating a suspended microbeam improving power efficiency. A waveguide and Bragg grating are defined through the middle of the microbeam via direct ultraviolet writing. A tuning range of 0.4 nm (50 GHz) is demonstrated at the telecommunication wavelength of 1550 nm. Power consumption during wavelength tuning is measured at 45 pm/mW, which is a factor of 90 better than reported values for similar bulk thermally tuned silica-on-silicon planar devices. The response time to a step change in heating is longer by a similar factor, as expected for a highly power-efficient device. The fabrication procedure involves a deep micromilling process, as well as wet etching and metal deposition. With this response, the device would be suitable for trimming applications and wherever low modulation frequencies are acceptable. A four-point-probe-based temperature measurement was also done to ascertain the temperature reached during tuning and found an average volume temperature of 48 °C, corresponding to 0.4 nm of tuning. The role of stress-induced buckling in device fabrication is included

Reactome: a knowledgebase of biological pathways

Reactome, located at http://www.reactome.org is a curated, peer-reviewed resource of human biological processes. Given the genetic makeup of an organism, the complete set of possible reactions constitutes its reactome. The basic unit of the Reactome database is a reaction; reactions are then grouped into causal chains to form pathways. The Reactome data model allows us to represent many diverse processes in the human system, including the pathways of intermediary metabolism, regulatory pathways, and signal transduction, and high-level processes, such as the cell cycle. Reactome provides a qualitative framework, on which quantitative data can be superimposed. Tools have been developed to facilitate custom data entry and annotation by expert biologists, and to allow visualization and exploration of the finished dataset as an interactive process map. Although our primary curational domain is pathways from Homo sapiens, we regularly create electronic projections of human pathways onto other organisms via putative orthologs, thus making Reactome relevant to model organism research communities. The database is publicly available under open source terms, which allows both its content and its software infrastructure to be freely used and redistributed

Dark Coupling and Gauge Invariance

We study a coupled dark energy-dark matter model in which the energy-momentum exchange is proportional to the Hubble expansion rate. The inclusion of its perturbation is required by gauge invariance. We derive the linear perturbation equations for the gauge invariant energy density contrast and velocity of the coupled fluids, and we determine the initial conditions. The latter turn out to be adiabatic for dark energy, when assuming adiabatic initial conditions for all the standard fluids. We perform a full Monte Carlo Markov Chain likelihood analysis of the model, using WMAP 7-year data.Comment: 16 pages, 2 figures, version accepted for publication in JCA

Fabrication and characterization of high-contrast mid-infrared GeTe₄ channel waveguides

We report the fabrication and characterization of high index contrast (Δn ~ 0.9) GeTe4 channel waveguides on ZnSe substrate for evanescent-field based biosensing applications in the mid-infrared spectral region. GeTe4 films were deposited by RF sputtering and characterized for their structure, composition, transparency and dispersion. The lift-off technique was used to pattern the waveguide channels. Waveguiding between 2.5-3.7 µm and 6.4-7.5 µm was demonstrated and mode intensity profile and estimated propagation losses are given for the 3.5 µm wavelength

The transmission of vertical vibration through seats: influence of the characteristics of the human body

The transmission of vibration through a seat depends on the impedance of the seat and the apparent mass of the seat occupant. This study was designed to determine how factors affecting the apparent mass of the body (age, gender, physical characteristics, backrest contact, and magnitude of vibration) affect seat transmissibility. The transmission of vertical vibration through a car seat was measured with 80 adults (41 males and 39 females aged 18–65) at frequencies between 0.6 and 20 Hz with two backrest conditions (no backrest and backrest), and with three magnitudes of random vibration (0.5, 1.0, and 1.5 m s-2 rms). Linear regression models were used to study the effects of subject physical characteristics (age, gender, and anthropometry) and features of their apparent mass (resonance frequency, apparent mass at resonance and at 12 Hz) on the measured seat transmissibility. The strongest predictor of both the frequency of the principal resonance in seat transmissibility and the seat transmissibility at resonance was subject age, with other factors having only marginal effects. The transmissibility of the seat at 12 Hz depended on subject age, body mass index, and gender. Although subject weight was strongly associated with apparent mass, weight was not strongly associated with seat transmissibility. The resonance frequency of the seat decreased with increases in the magnitude of the vibration excitation and increased when subjects made contact with the backrest. Inter-subject variability in the resonance frequency and transmissibility at resonance was less with greater vibration excitation, but was largely unaffected by backrest contact. A lumped parameter seat–person model showed that changes in seat transmissibility with age can be predicted from changes in apparent mass with age, and that the dynamic stiffness of the seat appeared to increase with increased loading so as to compensate for increases in subject apparent mass associated with increased sitting weight

On the growth of perturbations in interacting dark energy and dark matter fluids

The covariant generalizations of the background dark sector coupling suggested in G. Mangano, G. Miele and V. Pettorino, Mod. Phys. Lett. A 18, 831 (2003) are considered. The evolution of perturbations is studied with detailed attention to interaction rate that is proportional to the product of dark matter and dark energy densities. It is shown that some classes of models with coupling of this type do not suffer from early time instabilities in strong coupling regime.Comment: 11 pages, 2 figures. v3: minor changes, typos fixe