Spectrometer baseline control via spatial filtering.

An absorptive half-moon aperture mask is experimentally explored as a broad-bandwidth means of eliminating spurious spectral features arising from reprocessed radiation in an infrared Fourier transform spectrometer. In the presence of the spatial filter, an order of magnitude improvement in the fidelity of the spectrometer baseline is observed. The method is readily accommodated within the context of commonly employed instrument configurations and leads to a factor of two reduction in optical throughput. A detailed discussion of the underlying mechanism and limitations of the method are provided.

Large-aperture wide-bandwidth antireflection-coated silicon lenses for millimeter wavelengths.

The increasing scale of cryogenic detector arrays for submillimeter and millimeter wavelength astrophysics has led to the need for large aperture, high index of refraction, low loss, cryogenic refracting optics. Silicon with n=3.4, low loss, and high thermal conductivity is a nearly optimal material for these purposes but requires an antireflection (AR) coating with broad bandwidth, low loss, low reflectance, and a matched coefficient of thermal expansion. We present an AR coating for curved silicon optics comprised of subwavelength features cut into the lens surface with a custom three-axis silicon dicing saw. These features constitute a metamaterial that behaves as a simple dielectric coating. We have fabricated silicon lenses as large as 33.4 cm in diameter with micromachined layers optimized for use between 125 and 165 GHz. Our design reduces average reflections to a few tenths of a percent for angles of incidence up to 30° with low cross polarization. We describe the design, tolerance, manufacture, and measurements of these coatings and present measurements of the optical properties of silicon at millimeter wavelengths at cryogenic and room temperatures. This coating and lens fabrication approach is applicable from centimeter to submillimeter wavelengths and can be used to fabricate coatings with greater than octave bandwidth.

A broadband micro-machined far-infrared absorber.

The experimental investigation of a broadband far-infrared meta-material absorber is described. The observed absorptance is >0.95 from 1 to 20 THz (300-15 µm) over a temperature range spanning 5-300 K. The meta-material, realized from an array of tapers ≈100 µm in length, is largely insensitive to the detailed geometry of these elements and is cryogenically compatible with silicon-based micro-machined technologies. The electromagnetic response is in general agreement with a physically motivated transmission line model.

Redirecting traditional professional values to support safety: changing organisational culture in health care.

Professionals in healthcare organisations who seek to enhance safety and quality in an increasingly demanding industry environment often identify culture as a barrier to change. The cultural focus on individual autonomy, for example, seems to conflict with desired norms of teamwork, problem reporting, and learning. We offer a definition and explication of why culture is important to change efforts. A cultural analysis of health care suggests professional values that can be redirected to support change. We offer examples of organisations that drew upon cultural strengths to create new ways of working and gradually shifted the culture.

Targeting striatal metabotropic glutamate receptor type 5 in Parkinson's disease: bridging molecular studies and clinical trials.

Metabotropic glutamate (mGlu) receptors are G protein-coupled receptors expressed primarily on neurons and glial cells modulating the effects of glutamatergic neurotransmission. The pharmacological manipulation of these receptors has been postulated to be valuable in the management of some neurological disorders. Accordingly, the targeting of mGlu5 receptors as a therapeutic approach for Parkinson's disease (PD) has been proposed, especially to manage the adverse symptoms associated to chronic treatment with classical PD drugs. Thus, the specific pharmacological blocking of mGlu5 receptors constitutes one of the most attractive non-dopaminergic-based strategies for PD management in general and for the L-DOPA-induced dyskinesia (LID) in particular. Overall, we provide here an update of the current state of the art of these mGlu5 receptor-based approaches that are under clinical study as agents devoted to alleviate PD symptoms.

[Comparative study of Uromiron and 38% Lipiodol in sialography]. / Estudio comparativo de Uromiron y Lipiodol al 38% en sialografia.

A comparative study was undertaken to assess the properties of uromiron and lipiodol 38%, which are used as radiopaque materials in sialographic techniques, on 25 young adult outpatients of both sexes that were seen at the Dental School, University of Chile, Santiago. It was found that, although the radiopaque properties of uromiron were less than lipiodol 38%, the can be improved by increasing the amount of material injected into the duct system of the salivary glands. Likewise, uromiron exhibited a proper biological tolerance and a rapid emptying time, therefore the use of uromiron in sialographic techniques seems to be a proper alternative to lipiodol 38%.