1,686 research outputs found

    Rapid PCR assay for detecting common genetic variants arising in human pluripotent stem cell cultures

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    Human pluripotent stem cells (hPSCs) are prone to acquiring genetic changes upon prolonged culture. Particularly common are copy number changes, including gains of chromosomes 1q, 12p, 17q, and 20q, and/or loss of chromosomes 10p and 18q. The variant cells harboring common genetic changes display altered behaviors compared to their diploid counterparts, thus potentially impacting upon the validity of experimental results and safety of hPSC-derived cellular therapies. Hence, a critical quality attribute in hPSC maintenance should include frequent monitoring for genetic changes arising in cultures. This in turn places large demands on the genotyping assays for detection of genetic changes. Traditional methods for screening cells entail specialized cytogenetic analyses, but their high costs and a lengthy turnaround time make them impractical for high-throughput analyses and routine laboratory use. Here, we detail a protocol for a rapid, accessible, and affordable PCR-based method for detection of frequently occurring copy number changes in hPSCs

    Calibration and High Fidelity Measurement of a Quantum Photonic Chip

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    Integrated quantum photonic circuits are becoming increasingly complex. Accurate calibration of device parameters and detailed characterization of the prepared quantum states are critically important for future progress. Here we report on an effective experimental calibration method based on Bayesian updating and Markov chain Monte Carlo integration. We use this calibration technique to characterize a two qubit chip and extract the reflectivities of its directional couplers. An average quantum state tomography fidelity of 93.79+/-1.05% against the four Bell states is achieved. Furthermore, comparing the measured density matrices against a model using the non-ideal device parameters derived from the calibration we achieve an average fidelity of 97.57+/-0.96%. This pinpoints non-ideality of chip parameters as a major factor in the decrease of Bell state fidelity. We also perform quantum state tomography for Bell states while continuously varying photon distinguishability and find excellent agreement with theory

    Reconfigurable controlled two-qubit operation on a quantum photonic chip

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    Integrated quantum photonics is an appealing platform for quantum information processing, quantum communication and quantum metrology. In all these applications it is necessary not only to be able to create and detect Fock states of light but also to program the photonic circuits that implements some desired logical operation. Here we demonstrate a reconfigurable controlled two-qubit operation on a chip using a multiwaveguide interferometer with a tunable phase shifter. We find excellent agreement between theory and experiment, with a 0.98 \pm 0.02 average similarity between measured and ideal operations

    The Nuclear Ionized Gas in the Radio Galaxy M84 (NGC 4374)

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    We present optical images of the nucleus of the nearby radio galaxy M84 (NGC 4374 = 3C272.1) obtained with the Wide Field/Planetary Camera 2 (WFPC2) aboard the Hubble Space Telescope (HST). Our three images cover the Hα\alpha + [N II] emission lines as well as the V and I continuum bands. Analysis of these images confirms that the Hα\alpha + [N II] emission in the central 5'' (410 pc) is elongated along position angle (P.A.) \approx 72\arcdeg, which is roughly parallel to two nuclear dust lanes.Our high-resolution images reveal that the Hα\alpha + [N II] emission has three components, namely a nuclear gas disk,an `ionization cone', and outer filaments. The nuclear disk of ionized gas has diameter 1=82\approx 1'' = 82 pc and major axis P.A. \approx 58\arcdeg \pm 6\arcdeg. On an angular scale of 0\farcs5, the major axis of this nuclear gas disk is consistent with that of the dust. However, the minor axis of the gas disk (P.A. \approx 148\arcdeg) is tilted with respect to that of the filamentary Hα\alpha + [N II] emission at distances > 2'' from the nucleus; the minor axis of this larger scale gas is roughly aligned with the axis of the kpc-scale radio jets (P.A. \approx 170\arcdeg). The ionization cone (whose apex is offset by \approx 0\farcs3 south of the nucleus) extends 2'' from the nucleus along the axis of the southern radio jet. This feature is similar to the ionization cones seen in some Seyfert nuclei, which are also aligned with the radio axes.Comment: 11 pages plus 4 figure

    Cognitive emotion regulation strategies, alexithymia and dissociation in schizophrenia, a review and meta-analysis.

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    Many individuals with schizophrenia are reported to have maladaptive expression and processing of emotion. This may take the form of conscious and implicit processes. Potential regulatory processes underlying schizophrenia are reviewed. We aimed to estimate effect sizes, potential heterogeneity and publication bias across three areas of measurement: a range of cognitive emotion regulation strategies(1) (CERS), alexithymia and dissociation

    Demonstration of Free-space Reference Frame Independent Quantum Key Distribution

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    Quantum key distribution (QKD) is moving from research laboratories towards applications. As computing becomes more mobile, cashless as well as cardless payment solutions are introduced, and a need arises for incorporating QKD in a mobile device. Handheld devices present a particular challenge as the orientation and the phase of a qubit will depend on device motion. This problem is addressed by the reference frame independent (RFI) QKD scheme. The scheme tolerates an unknown phase between logical states that varies slowly compared to the rate of particle repetition. Here we experimentally demonstrate the feasibility of RFI QKD over a free-space link in a prepare and measure scheme using polarisation encoding. We extend the security analysis of the RFI QKD scheme to be able to deal with uncalibrated devices and a finite number of measurements. Together these advances are an important step towards mass production of handheld QKD devices

    National medicines policies – a review of the evolution and development processes

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    OBJECTIVES: Continuous provision of appropriate medicines of assured quality, in adequate quantities, and at reasonable prices is a concern for all national governments. A national medicines policy (NMP) developed in a collaborative fashion identifies strategies needed to meet these objectives and provides a comprehensive framework to develop all components of a national pharmaceutical sector. To meet the health needs of the population, there is a general need for medicine policies based on universal principles, but nevertheless adapted to the national situation. This review aims to provide a quantitative and qualitative (describing the historical development) study of the development process and evolution of NMPs. METHODS: The number of NMPs and their current status has been obtained from the results of the assessment of WHO Level I indicators. The policy formulation process is examined in more detail with case studies from four countries: Sri Lanka, Australia, former Yugoslav Republic of Macedonia and South Africa. RESULTS: The number of NMPs worldwide has increased in the last 25 years with the highest proportional increase in the last 5–10 years in high-income countries. Higher income countries seem to have more NMP implementation plans available and have updated their NMP more recently. The four case studies show that the development of a NMP is a complex process that is country specific. In addition, it demonstrates that an appropriate political window is needed for the policy to be passed (for South Africa and the FYR Macedonia, a major political event acted as a trigger for initiating the policy development). Policy-making does not stop with the official adoption of a policy but should create mechanisms for implementation and monitoring. The NMPs of the FYR Macedonia and Australia provide indicators for monitoring. CONCLUSIONS: To date, not all countries have a NMP since political pressure by national experts or non-governmental organizations is generally needed to establish a NMP. Case studies in four countries showed that the policy process is just as important as the policy document since the process must create a mechanism by which all stakeholders are brought together and a sense of collective ownership of the final policy may be achieved

    Coping with access barriers to non‐ communicable disease medicines: Qualitative patient interviews in eight counties in Kenya

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    There is rich literature on barriers to medicines access for the treatment of non-communicable diseases (NCDs) in high-income countries. Less is known about low- and middle-income countries, in particular the differences in coping with medicines access barrier by household wealth and disease. The aim of this study was to compare the coping mechanisms of patients with the lack of availability and affordability of cardio-vascular diseases, diabetes and asthma medicines in Kenya. This qualitative study was part of a larger mixed methods evaluation study conducted in eight counties of Kenya from 2016 to 2019. Forty-nine patient interviews at study end line explored their NCD journey, perceptions of availability, stockouts and affordability of NCD medicines, their enrollment in health insurance, and their relationship with the private chemists. Transcribed interviews were coded using Nvivo software. A two-step thematic approach was used, first conducting a priority coding which was followed by coding emerging and divergent theme

    Evaluation of pharmaceutical industry led access programmes: A standardised framework

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    Pharmaceutical industry-led access programmes are increasing in number and scope worldwide. We present a new standardised framework for evaluation of these programmes that includes three components: a taxonomy of 11 access programme strategies; a series of logic models, one for each strategy and a set of measurement indicators. The logic models describe pathways of potential programme impact. Concepts relevant across a broad range of strategies were prioritised for inclusion in logic models to ensure consistency and to facilitate synthesis and learning across programmes. Each concept has at least one corresponding measurement indicator with metadata that includes the definition, details on how it should be measured and recommended data sources. The framework establishes a shared language for the collection and reporting of meaningful industry-led access programme information
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