2,295 research outputs found

    Tomography of quantum dots in a non-hermitian photonic chip

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    © 2019 IEEE. Quantum optical information systems offer the potential for secure communication and fast quantum computation. To fully characterise a quantum optical system one has to use quantum tomography [1]. Integration of quantum optics onto photonic chips provides advantages such as miniaturisation and stability, and also significantly improves quantum tomography using both re-configurable [2], and more recently, simpler static designs [3,4]. These on-chip designs have, so far, only used probabilistic single photon sources. Here we are working towards quantum tomography using a true deterministic source - a quantum dot. The scheme of the proposed experiment is shown in Fig. 1A. So far we have fabricated and characterised the performance of an InGaAs quantum dot monolithically integrated into a microlens [5], and completed the design, fabrication and classical characterisation of a photonic chip for quantum tomography

    Feasibility of hydraulic separation in a novel anaerobic-anoxic upflow reactor for biological nutrient removal

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    ABSTRACT : This contribution deals with a novel anaerobic-anoxic reactor for biological nutrient removal (BNR) from wastewater, termed AnoxAn. In the AnoxAn reactor, the anaerobic and anoxic zones for phosphate removal and denitrification are integrated in a single continuous upflow sludge blanket reactor, aiming at high compactness and efficiency. Its application is envisaged in those cases where retrofitting of existing wastewater treatment plants for BNR, or the construction of new ones, is limited by the available surface area. The environmental conditions are vertically divided up inside the reactor with the anaerobic zone at the bottom and the anoxic zone above. The capability of the AnoxAn configuration to establish two hydraulically separated zones inside the single reactor was assessed by means of hydraulic characterization experiments and model simulations. Residence time distribution (RTD) experiments in clean water were performed in a bench-scale (48.4 L) AnoxAn prototype. The required hydraulic separation between the anaerobic and anoxic zones, as well as adequate mixing in the individual zones, was obtained through selected mixing devices. The observed behaviour was described by a hydraulic model consisting of continuous stirred tank reactors and plug-flow reactors. The impact of the denitrification process in the anoxic zone on the hydraulic separation was subsequently evaluated through model simulations. The desired hydraulic behaviour proved feasible, involving little mixing between the anaerobic and anoxic zones (mixing flowrate 40.2% of influent flowrate) and negligible nitrate concentration in the anaerobic zone (less than 0.1 mgN L-1) when denitrification was considered

    Microdevices for extensional rheometry of low viscosity elastic liquids : a review

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    Extensional flows and the underlying stability/instability mechanisms are of extreme relevance to the efficient operation of inkjet printing, coating processes and drug delivery systems, as well as for the generation of micro droplets. The development of an extensional rheometer to characterize the extensional properties of low viscosity fluids has therefore stimulated great interest of researchers, particularly in the last decade. Microfluidics has proven to be an extraordinary working platform and different configurations of potential extensional microrheometers have been proposed. In this review, we present an overview of several successful designs, together with a critical assessment of their capabilities and limitations

    Practical three color live cell imaging by widefield microscopy

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    Live cell fluorescence microscopy using fluorescent protein tags derived from jellyfish and coral species has been a successful tool to image proteins and dynamics in many species. Multi-colored aequorea fluorescent protein (AFP) derivatives allow investigators to observe multiple proteins simultaneously, but overlapping spectral properties sometimes require the use of sophisticated and expensive microscopes. Here, we show that the aequorea coerulescens fluorescent protein derivative, PS-CFP2 has excellent practical properties as a blue fluorophore that are distinct from green or red fluorescent proteins and can be imaged with standard filter sets on a widefield microscope. We also find that by widefield illumination in live cells, that PS-CFP2 is very photostable. When fused to proteins that form concentrated puncta in either the cytoplasm or nucleus, PSCFP2 fusions do not artifactually interact with other AFP fusion proteins, even at very high levels of over-expression. PSCFP2 is therefore a good blue fluorophore for distinct three color imaging along with eGFP and mRFP using a relatively simple and inexpensive microscope

    Tomography of quantum dots in a non-hermitian photonic chip

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    © COPYRIGHT SPIE. Downloading of the abstract is permitted for personal use only. Quantum optical information systems offer the potential for secure communication and fast quantum computation. To fully characterise a quantum optical system one has to use quantum tomography.1 The integration of quantum optics onto photonic chips provides advantages such as miniaturisation and stability, significantly improving quantum tomography using both re-configurable, and more recently, simpler static designs. These on-chip designs have, so far, only used probabilistic single photon sources. Here we are working towards quantum tomography using a true deterministic source-an InGaAs quantum dot

    The importance of baseline viral load when assessing relative efficacy in treatment-naïve HBeAg-positive chronic hepatitis B: a systematic review and network meta-analysis.

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    BACKGROUND: To date no network meta-analysis (NMA) has accounted for baseline variations in viral load when assessing the relative efficacy of interventions for chronic hepatitis B (CHB). We undertook baseline-adjusted and unadjusted analyses using the same data to explore the impact of baseline viral load (BVL) on CHB treatment response. METHODS: We searched Embase, Medline, Medline in Process and the Cochrane CENTRAL databases for randomised clinical trials (RCTs) of monotherapy interventions at licensed doses for use in CHB. Search strategies comprised CHB disease and drug terms (a combination of controlled vocabulary and free text terms) and also a bespoke RCT filter.The NMA was undertaken in WinBUGs using fixed and random effects methods, using data obtained from a systematic review. Individual patient data (IPD) from an entecavir clinical trial were used to quantify the impact of different baseline characteristics (in particular undetectable viral load (UVL) at 1 year) on relative treatment effect. Study level mean baseline values from all identified studies were used. Results were generated for UVL and presented as relative risks (RRs) and 95% credible intervals (CrIs) using entecavir as reference treatment. RESULTS: Overall, for all eight relevant interventions we identified 3,000 abstracts. Following full text review a total of 35 (including the contents of six clinical study reports) met the inclusion critera; 19 were in hepatitis B e antigen (HBeAg)-positive patients and 14 of the 19 contained outcome information of relevance to the NMA.Entecavir and tenofovir studies had heterogeneous patient populations in terms of BVL (mean values 9.29 and 8.65 log10 copies/ml respectively). After adjusting UVL for BVL using an informative prior based on the IPD analysis, the difference between entecavir and tenofovir was not statistically significant (RR 1.27, 95% CrI 0.96 to 1.47-fixed effects). A similar conclusion was found in all sensitivity analyses. Adjusted tenofovir results were more consistent with observed clinical trial response rates. CONCLUSIONS: This study demonstrates the importance of adjusting for BVL when assessing the relative efficacy of CHB interventions in achieving UVL. This has implications for both clinical and economic decision making

    An open-label, multicenter study to evaluate the safe and effective use of the single-use autoinjector with an Avonex® prefilled syringe in multiple sclerosis subjects

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    <p>Abstract</p> <p>Background</p> <p>The ability to self-inject in patients with multiple sclerosis (MS) has been associated with a reduced risk of missed injections and drug discontinuation, and a beneficial effect on patients' independence. However, injection anxiety, needle phobia and disease-related disability are major barriers to a patient's ability to self-administer treatment. Use of an autoinjector may improve patients' ability to self-inject. This study evaluated the safe and effective use of Avonex Pen™ (prefilled pen), a single use autoinjector, for intramuscular delivery of interferon beta-1a (IM IFNβ-1a, Avonex) in MS patients.</p> <p>Methods</p> <p>This was a Phase IIIb, open-label, single-country, multicenter trial in MS patients currently using IM IFNβ-1a prefilled syringes. Patients received weekly 30 mcg IM IFNβ-1a treatment over 4 weeks. On Day 1, patients self-administered IM IFNβ-1a using a prefilled syringe at the clinic. On Day 8, patients received training on the prefilled pen and self-administered IM IFNβ-1a using the device. On Day 15, patients self-administered IM IFNβ-1a at home using the prefilled pen. A final injection occurred at the clinic on Day 22 when patients self-administered IM IFNβ-1a using the prefilled pen while clinic staff observed and completed a detailed questionnaire documenting patients' ability to self-inject with the device. Serum neopterin levels were evaluated pre and post-injection on Days 1 and 8. Adverse events were monitored throughout.</p> <p>Results</p> <p>Seventy-one (96%) patients completed the study. The overall success rate in safely and effectively using the prefilled pen was 89%. No device malfunctions occurred. One unsuccessful administration occurred at Day 22 due to patient error; no patient injury resulted. Patients gave the prefilled pen high ratings (8.7-9.3) on a 10-point scale for ease of use (0 = extremely difficult, 10 = extremely easy). Ninety-four percent of patients preferred the prefilled pen over the prefilled syringe. Induction of serum neopterin levels, serving as a biomarker for type 1 interferon action, was similar to that of the prefilled syringe. The prefilled pen demonstrated a safety profile comparable to the prefilled syringe.</p> <p>Conclusions</p> <p>The prefilled pen is a safe and effective device for administration of IM IFNβ-1a and represents an alternative method for self-injection for MS patients using this therapy.</p> <p>Trial registration</p> <p>This study is registered at clinicaltrials.gov, identifier: <a href="http://www.clinicaltrials.gov/ct2/show/NCT00828204">NCT00828204</a></p

    A Multicentre Molecular Analysis of Hepatitis B and Blood-Borne Virus Coinfections in Viet Nam

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    Hepatitis B (HBV) infection is endemic in Viet Nam, with up to 8.4 million individuals estimated to be chronically infected. We describe results of a large, multicentre seroepidemiological and molecular study of the prevalence of HBV infection and blood-borne viral coinfections in Viet Nam. Individuals with varying risk factors for infection (n = 8654) were recruited from five centres; Ha Noi, Hai Phong, Da Nang, Khanh Hoa and Can Tho. A mean prevalence rate of 10.7% was observed and levels of HBsAg were significantly higher in injecting drug users (IDUs) (17.4%, n = 174/1000) and dialysis patients (14.3%, n = 82/575) than in lower-risk groups (9.4%; p<0.001). Coinfection with HIV was seen in 28% of HBV-infected IDUs (n = 49/174) and 15.2% of commercial sex workers (CSWs; n = 15/99). HCV infection was present in 89.8% of the HBV-HIV coinfected IDUs (n = 44/49) and 40% of HBV-HIV coinfected CSWs (n = 16/40). Anti-HDV was detected in 10.7% (n = 34/318) of HBsAg positive individuals. Phylogenetic analysis of HBV S gene (n = 187) showed a predominance of genotype B4 (82.6%); genotypes C1 (14.6%), B2 (2.7%) and C5 (0.5%) were also identified. The precore mutation G1896A was identified in 35% of all specimens, and was more frequently observed in genotype B (41%) than genotype C (3%; p<0.0001). In the immunodominant ‘a’ region of the surface gene, point mutations were identified in 31% (n = 58/187) of sequences, and 2.2% (n = 4/187) and 5.3% (n = 10/187) specimens contained the major vaccine escape mutations G145A/R and P120L/Q/S/T, respectively. 368 HBsAg positive individuals were genotyped for the IL28B SNP rs12979860 and no significant association between the IL28B SNP and clearance of HBsAg, HBV viral load or HBeAg was observed. This study confirms the high prevalence of HBV infection in Viet Nam and also highlights the significant levels of blood-borne virus coinfections, which have important implications for hepatitis-related morbidity and development of effective management strategies
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