Strong exciton–photon coupling in a low-Q all-metal mirror microcavity

Copyright © 2002 American Institute of Physics. This article may be downloaded for personal use only. Any other use requires prior permission of the author and the American Institute of Physics. The following article appeared in Applied Physics Letters 81 (2002) and may be found at http://link.aip.org/link/?APPLAB/81/3519/1We report the experimental observation of strong exciton–photon coupling in a planar microcavity composed of an organic semiconductor positioned between two metallic (silver) mirrors. Via transmission and reflectivity measurements, we observe a very large, room temperature Rabi splitting in excess of 300 meV. We show that the Rabi-splitting is enhanced in all-metal microcavities by a factor of more than 2 compared to an organic film positioned between a silver mirror and a dielectric mirror. This enhancement results from the significantly larger optical fields that are confined within all-metal microcavities

The role of algal organic matter in the separation of algae and cyanobacteria using the novel “Posi” - Dissolved air flotation process

Algae and cyanobacteria frequently require separation from liquid media in both water treatment and algae culturing for biotechnology applications. The effectiveness of cell separation using a novel dissolved air flotation process that incorporates positively charged bubbles (PosiDAF) has recently been of interest but has been shown to be dependent on the algae or cyanobacteria species tested. Previously, it was hypothesised that algal organic matter (AOM) could be impacting the separation efficiency. Hence, this study investigates the influence of AOM on cell separation using PosiDAF, in which bubbles are modified using a commercially available cationic polyelectrolyte poly(N, N-diallyl-N,N-dimethylammonium chloride) (PDADMAC). The separation of Chlorella vulgaris CS-42/7, Mychonastes homosphaera CS-556/01 and two strains of Microcystis aeruginosa (CS-564/01 and CS-555/1), all of which have similar cell morphology but different AOM character, was investigated. By testing the cell separation in the presence and absence of AOM, it was determined that AOM enhanced cell separation for all the strains but to different extents depending on the quantity and composition of carbohydrates and proteins in the AOM. By extracting AOM from the strain for which optimal separation was observed and adding it to the others, cell separation improved from 90%. This was attributed to elevated levels of acidic carbohydrates as well as glycoprotein-carbohydrate conjugations, which in turn were related to the nature and quantity of proteins and carbohydrates present in the AOM. Therefore, it was concluded that process optimisation requires an in-depth understanding of the AOM and its components. If culturing algae for biotechnology applications, this indicates that strain selection is not only important with respect to high value product content, but also for cell separation

Imaging with ultrasound in physical therapy: What is the PT’s scope of practice? A competency-based educational model and training recommendations.

Physical therapists employ ultrasound (US) imaging technology for a broad range of clinical and research purposes. Despite this, few physical therapy regulatory bodies guide the use of US imaging, and there are limited continuing education opportunities for physical therapists to become proficient in using US within their professional scope of practice. Here, we (i) outline the current status of US use by physical therapists; (ii) define and describe four broad categories of physical therapy US applications (ie, rehabilitation, diagnostic, intervention and research US); (iii) discuss how US use relates to the scope of high value physical therapy practice and (iv) propose a broad framework for a competency-based education model for training physical therapists in US. This paper only discusses US imaging— not ’therapeutic’ US. Thus, ’imaging’ is implicit anywhere the term ’ultrasound’ is used.pre-print847 K

Amisulpride augmentation in clozapine-unresponsive schizophrenia: A double-blind, placebo-controlled, randomised trial of clinical and cost-effectiveness.

BACKGROUND: When treatment-refractory schizophrenia shows an insufficient response to a trial of clozapine, clinicians commonly add a second antipsychotic, despite the lack of robust evidence to justify this practice. OBJECTIVES: The main objectives of the study were to establish the clinical effectiveness and cost-effectiveness of augmentation of clozapine medication with a second antipsychotic, amisulpride, for the management of treatment-resistant schizophrenia. DESIGN: The study was a multicentre, double-blind, individually randomised, placebo-controlled trial with follow-up at 12 weeks. SETTINGS: The study was set in NHS multidisciplinary teams in adult psychiatry. PARTICIPANTS: Eligible participants were people aged 18-65 years with treatment-resistant schizophrenia unresponsive, at a criterion level of persistent symptom severity and impaired social function, to an adequate trial of clozapine monotherapy. INTERVENTIONS: Interventions comprised clozapine augmentation over 12 weeks with amisulpride or placebo. Participants received 400 mg of amisulpride or two matching placebo capsules for the first 4 weeks, after which there was a clinical option to titrate the dosage of amisulpride up to 800 mg or four matching placebo capsules for the remaining 8 weeks. MAIN OUTCOME MEASURES: The primary outcome measure was the proportion of 'responders', using a criterion response threshold of a 20% reduction in total score on the Positive and Negative Syndrome Scale. RESULTS: A total of 68 participants were randomised. Compared with the participants assigned to placebo, those receiving amisulpride had a greater chance of being a responder by the 12-week follow-up (odds ratio 1.17, 95% confidence interval 0.40 to 3.42) and a greater improvement in negative symptoms, although neither finding had been present at 6-week follow-up and neither was statistically significant. Amisulpride was associated with a greater side effect burden, including cardiac side effects. Economic analyses indicated that amisulpride augmentation has the potential to be cost-effective in the short term [net saving of between £329 and £2011; no difference in quality-adjusted life-years (QALYs)] and possibly in the longer term. LIMITATIONS: The trial under-recruited and, therefore, the power of statistical analysis to detect significant differences between the active and placebo groups was limited. The economic analyses indicated high uncertainty because of the short duration and relatively small number of participants. CONCLUSIONS: The risk-benefit of amisulpride augmentation of clozapine for schizophrenia that has shown an insufficient response to a trial of clozapine monotherapy is worthy of further investigation in larger studies. The size and extent of the side effect burden identified for the amisulpride-clozapine combination may partly reflect the comprehensive assessment of side effects in this study. The design of future trials of such a treatment strategy should take into account that a clinical response may be not be evident within the 4- to 6-week follow-up period usually considered adequate in studies of antipsychotic treatment of acute psychotic episodes. Economic evaluation indicated the need for larger, longer-term studies to address uncertainty about the extent of savings because of amisulpride and impact on QALYs. The extent and nature of the side effect burden identified for the amisulpride-clozapine combination has implications for the nature and frequency of safety and tolerability monitoring of clozapine augmentation with a second antipsychotic in both clinical and research settings. TRIAL REGISTRATION: EudraCT number 2010-018963-40 and Current Controlled Trials ISRCTN68824876. FUNDING: This project was funded by the National Institute for Health Research (NIHR) Health Technology Assessment programme and will be published in full in Health Technology Assessment; Vol. 21, No. 49. See the NIHR Journals Library website for further project information

Monitoring river periphyton with artificial benthic substrates

The objective of this research was to identify the materials and methods necessary to study the attached algal community on a river bottom in deep water. The study site was the Susquehanna River near Falls, Pennsylvania. Artificial substrates of smooth glass, frosted glass, Vermont slate, ‘sandy slate’ (flagstone) and acrylic plate were placed on the stream bottom in detritus free sample holders by scuba divers. Both monthly and long-term cumulative samples were collected from the plates employing scuba and a Bar-Clamp sampler. River stones (natural substrates) were collected for comparison. Samples were analyzed in a Palmer Cell under a Bausch and Lomb research microscope. Diatoms were the most important colonizers of river stones, with the genera Nitzschia and Navicula most abundant. Highest periphyton densities occurred on natural substrates in winter with a maximum of 2.2 × 10 4 units/ mm 2 . Artificial substrates with one month exposure periods accumulated maximum periphyton density from May through October with relatively low densities in winter. Cumulative artificial substrates were most like river stones in patterns of colonization. Frosted acrylic is recommended for future studies employing benthic artificial periphyton substrates.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/42907/1/10750_2004_Article_BF00046798.pd

Genetic risk and a primary role for cell-mediated immune mechanisms in multiple sclerosis.

Multiple sclerosis is a common disease of the central nervous system in which the interplay between inflammatory and neurodegenerative processes typically results in intermittent neurological disturbance followed by progressive accumulation of disability. Epidemiological studies have shown that genetic factors are primarily responsible for the substantially increased frequency of the disease seen in the relatives of affected individuals, and systematic attempts to identify linkage in multiplex families have confirmed that variation within the major histocompatibility complex (MHC) exerts the greatest individual effect on risk. Modestly powered genome-wide association studies (GWAS) have enabled more than 20 additional risk loci to be identified and have shown that multiple variants exerting modest individual effects have a key role in disease susceptibility. Most of the genetic architecture underlying susceptibility to the disease remains to be defined and is anticipated to require the analysis of sample sizes that are beyond the numbers currently available to individual research groups. In a collaborative GWAS involving 9,772 cases of European descent collected by 23 research groups working in 15 different countries, we have replicated almost all of the previously suggested associations and identified at least a further 29 novel susceptibility loci. Within the MHC we have refined the identity of the HLA-DRB1 risk alleles and confirmed that variation in the HLA-A gene underlies the independent protective effect attributable to the class I region. Immunologically relevant genes are significantly overrepresented among those mapping close to the identified loci and particularly implicate T-helper-cell differentiation in the pathogenesis of multiple sclerosis