On-chip indistinguishable photons using III-V nanowire/SiN hybrid integration

We demonstrate on-chip generation of indistinguishable photons based on a nanowire quantum dot. From a growth substrate containing arrays of positioned-controlled single dot nanowires, we select a single nanowire which is placed on a SiN waveguide fabricated on a Si-based chip. Coupling of the quantum dot emission to the SiN waveguide is via the evanescent mode in the tapered nanowire. Post-selected two-photon interference visibilities using continuous wave excitation above-band and into a p-shell of the dot were 100%, consistent with a single photon source having negligible multi-photon emission probability. Visibilities over the entire photon wavepacket, measured using pulsed excitation, were reduced by a factor of 5 when exciting quasi-resonantly and by a factor of 10 for above-band excitation. The role of excitation timing jitter, spectral diffusion and pure dephasing in limiting visibilities over the temporal extent of the photon is investigated using additional measurements of the coherence and linewidth of the emitted photons

Socially-marketed rapid diagnostic tests and ACT in the private sector: ten years of experience in Cambodia.

Whilst some populations have recently experienced dramatic declines in malaria, the majority of those most at risk of Plasmodium falciparum malaria still lack access to effective treatment with artemisinin combination therapy (ACT) and others are already facing parasites resistant to artemisinins.In this context, there is a crucial need to improve both access to and targeting of ACT through greater availability of good quality ACT and parasitological diagnosis. This is an issue of increasing urgency notably in the private commercial sector, which, in many countries, plays an important role in the provision of malaria treatment. The Affordable Medicines Facility for malaria (AMFm) is a recent initiative that aims to increase the provision of affordable ACT in public, private and NGO sectors through a manufacturer-level subsidy. However, to date, there is little documented experience in the programmatic implementation of subsidized ACT in the private sector. Cambodia is in the unique position of having more than 10 years of experience not only in implementing subsidized ACT, but also rapid diagnostic tests (RDT) as part of a nationwide social marketing programme. The programme includes behaviour change communication and the training of private providers as well as the sale and distribution of Malarine, the recommended ACT, and Malacheck, the RDT. This paper describes and evaluates this experience by drawing on the results of household and provider surveys conducted since the start of the programme. The available evidence suggests that providers' and consumers' awareness of Malarine increased rapidly, but that of Malacheck much less so. In addition, improvements in ACT and RDT availability and uptake were relatively slow, particularly in more remote areas.The lack of standardization in the survey methods and the gaps in the data highlight the importance of establishing a clear system for monitoring and evaluation for similar initiatives. Despite these limitations, a number of important lessons can still be learnt. These include the importance of a comprehensive communications strategy and of a sustained and reliable supply of products, with attention to the geographical reach of both. Other important challenges relate to the difficulty in incentivising providers and consumers not only to choose the recommended drug, but to precede this with a confirmatory blood test and ensure that providers adhere to the test results and patients to the treatment regime. In Cambodia, this is particularly complicated due to problems inherent to the drug itself and the emergence of artemisinin resistance

Costs and cost-effectiveness of Plasmodium vivax control

The continued success of efforts to reduce the global malaria burden will require sustained funding for interventions specifically targeting Plasmodium vivax The optimal use of limited financial resources necessitates cost and cost-effectiveness analyses of strategies for diagnosing and treating P. vivax and vector control tools. Herein, we review the existing published evidence on the costs and cost-effectiveness of interventions for controlling P. vivax, identifying nine studies focused on diagnosis and treatment and seven studies focused on vector control. Although many of the results from the much more extensive P. falciparum literature can be applied to P. vivax, it is not always possible to extrapolate results from P. falciparum-specific cost-effectiveness analyses. Notably, there is a need for additional studies to evaluate the potential cost-effectiveness of radical cure with primaquine for the prevention of P. vivax relapses with glucose-6-phosphate dehydrogenase testing

Considering Grand Challenges in Biology Education : Rationales and Proposals for Future Investigations to Guide Instruction and Enhance Student Understanding in the Life Sciences

An international group of biology education researchers offer their views on areas of scholarship that might positively impact our understanding of teaching and learning in biology and potentially inform practices in biology and life science instruction. This article contains a series of essays on topics that include a framework for biology education research, considerations in the preparation of biology teachers, increasing accessibility to biology for all learners, the role and challenges of language in biology teaching, sociocultural issues in biology instruction, and assisting students in coping with scientific innovations. These contributions are framed by a discussion of the value of defining several potential “grand challenges” in biology education

Considering Grand Challenges in Biology Education : Rationales and Proposals for Future Investigations to Guide Instruction and Enhance Student Understanding in the Life Sciences

An international group of biology education researchers offer their views on areas of scholarship that might positively impact our understanding of teaching and learning in biology and potentially inform practices in biology and life science instruction. This article contains a series of essays on topics that include a framework for biology education research, considerations in the preparation of biology teachers, increasing accessibility to biology for all learners, the role and challenges of language in biology teaching, sociocultural issues in biology instruction, and assisting students in coping with scientific innovations. These contributions are framed by a discussion of the value of defining several potential “grand challenges” in biology education

PKA-induced dimerization of the RhoGAP DLC1 promotes its inhibition of tumorigenesis and metastasis

Deleted in Liver Cancer 1 (DLC1) is a tumour suppressor that encodes a RhoGTPase-activating protein (RhoGAP) and is frequently inactivated in many human cancers. The RhoGAP activity of DLC1 against Rho signalling is well documented and is strongly associated with the tumour suppressor functions of DLC1. However, the mechanism by which the RhoGAP activity of DLC1 is regulated remains obscure. Here, we report that phosphorylation of DLC1 at Ser549 by cyclic AMP-dependent protein kinase A contributes to enhanced RhoGAP activity and promotes the activation of DLC1, which suppresses hepatoma cell growth, motility and metastasis in both in vitro and in vivo models. Intriguingly, we found that Ser549 phosphorylation induces the dimerization of DLC1 and that inducible dimerization of DLC1 can rescue the tumour suppressive and RhoGAP activities of DLC1 containing a Ser549 deletion. Our study establishes a novel regulatory mechanism for DLC1 RhoGAP activity via dimerization induced by protein kinase A signalling. © 2013 Macmillan Publishers Limited. All rights reserved.Link_to_subscribed_fulltex

Prevention of Morbidity in sickle cell disease - qualitative outcomes, pain and quality of life in a randomised cross-over pilot trial of overnight supplementary oxygen and auto-adjusting continuous positive airways pressure (POMS2a):Study protocol for a randomised controlled trial

BACKGROUND: Sickle cell anaemia (SCA) is an inherited disorder of haemoglobin. Patients experience long-term health care problems, affecting quality of life (QOL) including frequent acute pain, which is difficult to document in trials except as hospital admissions. Pilot data suggests that overnight respiratory support, either supplementary oxygen or auto-adjusting continuous positive airways pressure (APAP), is safe and may have clinical benefit. This pilot trial aims to determine which intervention is more acceptable to participants and whether there are other advantages of one over the other, e.g. in respiratory function or haematological parameters, before conducting the Phase 2 trial of overnight respiratory support funded by the National Institutes of Health Research.METHODS/DESIGN: This is a pilot cross-over interventional trial with the order of interventions decided by simple randomization. Ten adults (age over 18 years) and 10 children (aged between 8 and 18 years) with homozygous sickle cell disease (haemoglobin SS, HbSS), recruited regardless of symptoms of sleep-disordered breathing, will undergo overnight pulse oximetry and will have two interventions, overnight oxygen and APAP, for a week each in randomised order with a washout week between interventions. Participants will complete online diaries via an iPad throughout the 29 days of the study and will complete QOL questionnaires and have measurement of haematology, biochemistry, spirometry and lung volumes (adults only) at 3 time points, at baseline and after each intervention, as well as in-depth semi-structured qualitative interviews after each intervention, carried out by an experienced psychologist. Both qualitative and statistical methods will be used to analyze the data. The primary outcome is qualitative data looking at participant experience from the transcribed interviews after each intervention. The participant's view on feasibility, acceptability and preference will specifically be explored. The QOL, laboratory and lung function data will be compared with baseline for each arm.DISCUSSION: Patient and public involvement is an integral part of this trial and the key outcome is the qualitative result, which is dependent on obtaining good quality data to advise on participant feasibility, acceptability and preference. This is being addressed by using a standard interview. The development of a pain endpoint is another important outcome and collecting daily measurements is likely to be challenging. Research results will be used to inform design of the Phase 2 trial.TRIAL REGISTRATION: ISRCTN46078697 18 July 2014