409 research outputs found

    Fast wavelength switching lasers using two-section slotted Fabry-PĂŠrot structures

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    Fast wavelength switching of a two-section slotted Fabry–PÉrot laser structure is presented. The slot design enables operation at five discrete wavelength channels spaced by 10 nm by tuning one section of the device. These wavelengths operate with sidemode suppression ratio in excess of 35 dB, and switching times between these channels of approximately 1 ns are demonstrated

    Lasing from semiconductor microring on the end of an optical fiber

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    Isolated InGaAsP microrings with an outer diameter of 5.8 mum, a width of 1 mum, and a thickness of 0.41 mum were fabricated by epitaxial separation. Individual devices were bonded to multimode optical fiber using Van der Waals forces and optically pumped through the fiber. Lasing around 1505 nm was measured under pulsed and cw pumping at room temperature. The threshold pump power for pulsed operation was estimated to be 38 and 80 muW for cw operation. Multiple radial and azimuthal modes were present due to strong, three-dimensional confinement. Under strong pulsed pumping thermal effects caused the emission wavelength to chirp. (C) 2002 American Institute of Physics. (DOI: 10.1063/1.1496496

    Il tema del “doppio” nel romanzo di A. Skaldin Stranstvia i priključenija Nikodima Staršego

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    L’«inspiegabile divisione» (неизъяснимое разделение) psicofisica della personalità sperimentata dal giovane barin Nikodim Michajlovič Ipat’ev, protagonista del romanzo filosofico di Aleksej Skaldin Stranstvija i priključenija Nikodima Staršego [Peregrinazioni e avventure di Nikodim il Vecchio]4, va certamente letta come un tributo dell’ultimo (in ordine cronologico) dei simbolisti russi ad un tema di antica memoria, caro alla mitologia e alla classicità – quello del “doppio” –, che, a partire da Pogorel’skij, passando per Puškin, Odoevskij, Gogol’ e Dostoevskij, aveva imperversato nell’Ottocento russo e, prima ancora, nell’ambiente letterario europeo barocco e romantico, confermandosi nel Novecento, secolo del relativismo e della crisi dell’io, come il tratto distintivo della modernità. Eppure lo sdoppiamento, a detta di Pasolini «la più grande delle invenzioni letterarie», se ricollega Skaldin alla grande tradizione culturale otto-novecentesca, è un Leitmotiv che l’autore desume non da fonti esterne ma dall’intimo della propria esperienza personale. La mia analisi della scissione identitaria del Nikodim skaldiniano si basa appunto sull’ipotesi di una totale o parziale identificazione dello scrittore con il suo personaggio, nella convinzione che solo un accurato esame del substratum autobiografico dell’opera ci possa restituire il significato e la funzione che in essa riveste il topos della destrutturazione e moltiplicazione dell’io

    A brief cognitive behavioural intervention for regular amphetamine users. A treatment guide.

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    A brief intervention using motivational and cognitive behavioural approaches to help change drug use. Also offer alternative brief interventions for clients not suited to the current approach. This manual is divided into five sections: Section 1. Context • Key points from the National Drug Strategy Monograph No 51. Models of Intervention and Care for Psychostimulant Users are included to present the evidence supporting this type of intervention for regular amphetamine users. • A flow-chart to place the intervention in a treatment context. Section 2. Brief background to the study and summary of results of evaluation • A brief description of how the study was developed, undertaken and evaluated. • A brief description of the evaluation outcome data (detailed results will be published separately). Section 3. The intervention • The CBT intervention is presented in a clear and easy to use format for practitioners. Section 4. Suggested alternative brief interventions for those not suitable for the current intervention • This section provides an overview of recommendations for alternative interventions for psychostimulant users who are unsuitable for the CBT intervention (e.g. those who are not considering change, experimental users etc). Section 5. Other available resources • This section lists a range of other resources that are currently available for practitioners working with psychostimulant users. This treatment guide has not been designed to stand alone. Rather, practitioners are encouraged to: 1. Acquaint themselves with the current research and clinical literature. The recently completed monograph Models of Intervention and Care for Psychostimulant Users is an excellent resource for current evidence supporting practice in this area. 2. Undertake training in CBT and motivational enhancement techniques if unfamiliar with these approaches. 3. Obtain ongoing clinical supervision

    The effect of influenza virus on the human oropharyngeal microbiome

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    Š The Author(s) 2018. Background. Secondary bacterial infections are an important cause of morbidity and mortality associated with influenza infections. As bacterial disease can be caused by a disturbance of the host microbiome, we examined the impact of influenza on the upper respiratory tract microbiome in a human challenge study. Methods. The dynamics and ecology of the throat microbiome were examined following an experimental influenza challenge of 52 previously-healthy adult volunteers with influenza A/Wisconsin/67/2005 (H3N2) by intranasal inoculation; 35 healthy control subjects were not subjected to the viral challenge. Serial oropharyngeal samples were taken over a 30-day period, and the V1-V3 region of the bacterial 16S ribosomal RNA sequences were amplified and sequenced to determine the composition of the microbiome. The carriage of pathogens was also detected. Results. Of the 52 challenged individuals, 43 developed proven influenza infections, 33 of whom became symptomatic. None of the controls developed influenza, although 22% reported symptoms. The diversity of bacterial communities remained remarkably stable following the acquisition of influenza, with no significant differences over time between individuals with influenza and those in the control group. Influenza infection was not associated with perturbation of the microbiome at the level of phylum or genus. There was no change in colonization rates with Streptococcus pneumoniae or Neisseria meningitidis. Conclusions. The throat microbiota is resilient to influenza infection, indicating the robustness of the upper-airway microbiome

    Episodic Radiations in the Fly Tree of Life

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    Flies are one of four superradiations of insects (along with beetles, wasps, and moths) that account for the majority of animal life on Earth. Diptera includes species known for their ubiquity (Musca domestica house fly), their role as pests (Anopheles gambiae malaria mosquito), and their value as model organisms across the biological sciences (Drosophila melanogaster). A resolved phylogeny for flies provides a framework for genomic, developmental, and evolutionary studies by facilitating comparisons across model organisms, yet recent research has suggested that fly relationships have been obscured by multiple episodes of rapid diversification. We provide a phylogenomic estimate of fly relationships based on molecules and morphology from 149 of 157 families, including 30 kb from 14 nuclear loci and complete mitochondrial genomes combined with 371 morphological characters. Multiple analyses show support for traditional groups (Brachycera, Cyclorrhapha, and Schizophora) and corroborate contentious findings, such as the anomalous Deuterophlebiidae as the sister group to all remaining Diptera. Our findings reveal that the closest relatives of the Drosophilidae are highly modified parasites (including the wingless Braulidae) of bees and other insects. Furthermore, we use micro-RNAs to resolve a node with implications for the evolution of embryonic development in Diptera. We demonstrate that flies experienced three episodes of rapid radiation—lower Diptera (220 Ma), lower Brachycera (180 Ma), and Schizophora (65 Ma)—and a number of life history transitions to hematophagy, phytophagy, and parasitism in the history of fly evolution over 260 million y

    Assessment of function and clinical utility of alcohol and other drug web sites: An observational, qualitative study

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    Background The increasing popularity and use of the internet makes it an attractive option for providing health information and treatment, including alcohol/other drug use. There is limited research examining how people identify and access information about alcohol or other drug (AOD) use online, or how they assess the usefulness of the information presented. This study examined the strategies that individuals used to identify and navigate a range of AOD websites, along with the attitudes concerning presentation and content. Methods Members of the general community in Brisbane and Roma (Queensland, Australia) were invited to participate in a 30-minute search of the internet for sites related to AOD use, followed by a focus group discussion. Fifty one subjects participated in the study across nine focus groups. Results Participants spent a maximum of 6.5 minutes on any one website, and less if the user was under 25 years of age. Time spent was as little as 2 minutes if the website was not the first accessed. Participants recommended that AOD-related websites should have an engaging home or index page, which quickly and accurately portrayed the site’s objectives, and provided clear site navigation options. Website content should clearly match the title and description of the site that is used by internet search engines. Participants supported the development of a portal for AOD websites, suggesting that it would greatly facilitate access and navigation. Treatment programs delivered online were initially viewed with caution. This appeared to be due to limited understanding of what constituted online treatment, including its potential efficacy. Conclusions A range of recommendations arise from this study regarding the design and development of websites, particularly those related to AOD use. These include prudent use of text and information on any one webpage, the use of graphics and colours, and clear, uncluttered navigation options. Implications for future website development are discussed

    CD10−/ALDH− cells are the sole cisplatin-resistant component of a novel ovarian cancer stem cell hierarchy

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    It is long established that tumour-initiating cancer stem cells (CSCs) possess chemoresistant properties. However, little is known of the mechanisms involved, particularly with respect to the organisation of CSCs as stem-progenitor-differentiated cell hierarchies. Here we aimed to elucidate the relationship between CSC hierarchies and chemoresistance in an ovarian cancer model. Using a single cell-based approach to CSC discovery and validation, we report a novel, four-component CSC hierarchy based around the markers cluster of differentiation 10 (CD10) and aldehyde dehydrogenase (ALDH). In a change to our understanding of CSC biology, resistance to chemotherapy drug cisplatin was found to be the sole property of CD10−/ALDH− CSCs, while all four CSC types were sensitive to chemotherapy drug paclitaxel. Cisplatin treatment quickly altered the hierarchy, resulting in a three-component hierarchy dominated by the cisplatin-resistant CD10−/ALDH− CSC. This organisation was found to be hard-wired in a long-term cisplatin-adapted model, where again CD10−/ALDH− CSCs were the sole cisplatin-resistant component, and all CSC types remained paclitaxel-sensitive. Molecular analysis indicated that cisplatin resistance is associated with inherent- and adaptive-specific drug efflux and DNA-damage repair mechanisms. Clinically, low CD10 expression was consistent with a specific set of ovarian cancer patient samples. Collectively, these data advance our understanding of the relationship between CSC hierarchies and chemoresistance, which was shown to be CSC- and drug-type specific, and facilitated by specific and synergistic inherent and adaptive mechanisms. Furthermore, our data indicate that primary stage targeting of CD10−/ALDH− CSCs in specific ovarian cancer patients in future may facilitate targeting of recurrent disease, before it ever develops

    A host transcriptional signature for presymptomatic detection of infection in humans exposed to influenza H1N1 or H3N2.

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    There is great potential for host-based gene expression analysis to impact the early diagnosis of infectious diseases. In particular, the influenza pandemic of 2009 highlighted the challenges and limitations of traditional pathogen-based testing for suspected upper respiratory viral infection. We inoculated human volunteers with either influenza A (A/Brisbane/59/2007 (H1N1) or A/Wisconsin/67/2005 (H3N2)), and assayed the peripheral blood transcriptome every 8 hours for 7 days. Of 41 inoculated volunteers, 18 (44%) developed symptomatic infection. Using unbiased sparse latent factor regression analysis, we generated a gene signature (or factor) for symptomatic influenza capable of detecting 94% of infected cases. This gene signature is detectable as early as 29 hours post-exposure and achieves maximal accuracy on average 43 hours (p = 0.003, H1N1) and 38 hours (p-value = 0.005, H3N2) before peak clinical symptoms. In order to test the relevance of these findings in naturally acquired disease, a composite influenza A signature built from these challenge studies was applied to Emergency Department patients where it discriminates between swine-origin influenza A/H1N1 (2009) infected and non-infected individuals with 92% accuracy. The host genomic response to Influenza infection is robust and may provide the means for detection before typical clinical symptoms are apparent
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