Optimization of magnetic actuation protocol to enhance mass transfer in solid/liquid microfluidic systems

This paper was presented at the 4th Micro and Nano Flows Conference (MNF2014), which was held at University College, London, UK. The conference was organised by Brunel University and supported by the Italian Union of Thermofluiddynamics, IPEM, the Process Intensification Network, the Institution of Mechanical Engineers, the Heat Transfer Society, HEXAG - the Heat Exchange Action Group, and the Energy Institute, ASME Press, LCN London Centre for Nanotechnology, UCL University College London, UCL Engineering, the International NanoScience Community, www.nanopaprika.eu.The dynamic properties of a 250 m magnetic microparticle in a time varying magnetic field have been studied in a PDMS microreactor with a diameter of 13 mm using a dual coupled quadrupolar arrangement of electromagnets. A sinusoidal applied magnetic field has dictated a circular motion of the particles in the microreactor in the frequency range below 0.6 Hz. Different circular motion modes have been observed at higher frequencies of the applied field. The particular symmetric arrangement of the magnets has allowed a non-steady-state motion with variation in velocity between magnetic poles. The motion of magnetic particle has been described in terms of average velocity and mean square deviation from average velocity. The effect of actuation protocol parameters (frequency, magnetic field strength and phase shift) on particle velocity and acceleration has been investigated. The maximum average velocity of 0.016 m/s has been observed under an optimized actuation protocol. The mass transfer rate towards the particle surface is mainly influenced by the average velocity while the effect of acceleration/deceleration of the particle has an order of magnitude less influence

Magnetic actuation of microparticles for mass transfer enhancement

This paper was presented at the 4th Micro and Nano Flows Conference (MNF2014), which was held at University College, London, UK. The conference was organised by Brunel University and supported by the Italian Union of Thermofluiddynamics, IPEM, the Process Intensification Network, the Institution of Mechanical Engineers, the Heat Transfer Society, HEXAG - the Heat Exchange Action Group, and the Energy Institute, ASME Press, LCN London Centre for Nanotechnology, UCL University College London, UCL Engineering, the International NanoScience Community, www.nanopaprika.eu.The motion of magnetic microparticles (250μm diameter) in a circular microfluidic reactor with a diameter of 10 mm under time dependent magnetic field has been studied using CFD code COMSOL. The effect of actuation protocol on the local and average particle velocity has been investigated. The local Sh numbers were obtained as a function of angular particle position in the range of Re numbers between 0.05 and 10 while the particle velocity was changed over two orders of magnitude. Under time dependent magnetic field, the thickness of the boundary layer continuously changes which results in an increased mass transfer towards the particle surface under periodic particle velocity conditions as compared to steady state velocity conditions. A good agreement between numerical and experimental data has been observed

Not Perfect, but Better: Primary Care Providers’ Experiences with Electronic Referrals in a Safety Net Health System

BackgroundElectronic referrals can improve access to subspecialty care in safety net settings. In January 2007, San Francisco General Hospital (SFGH) launched an electronic referral portal that incorporated subspecialist triage, iterative communication with referring providers, and existing electronic health record data to improve access to subspecialty care.ObjectiveWe surveyed primary care providers (PCPs) to assess the impact of electronic referrals on workflow and clinical care.DesignWe administered an 18-item, web-based questionnaire to all 368 PCPs who had the option of referring to SFGH.MeasurementsWe asked participants to rate time spent submitting a referral, guidance of workup, wait times, and change in overall clinical care compared to prior referral methods using 5-point Likert scales. We used multivariate logistic regression to identify variables associated with perceived improvement in overall clinical care.ResultsTwo hundred ninety-eight PCPs (81.0%) from 24 clinics participated. Over half (55.4%) worked at hospital-based clinics, 27.9% at county-funded community clinics, and 17.1% at non-county-funded community clinics. Most (71.9%) reported that electronic referrals had improved overall clinical care. Providers from non-county-funded clinics (AOR 0.40, 95% CI 0.14-0.79) and those who spent > or =6 min submitting an electronic referral (AOR 0.33, 95%CI 0.18-0.61) were significantly less likely than other participants to report that electronic referrals had improved clinical care.ConclusionsPCPs felt electronic referrals improved health-care access and quality; those who reported a negative impact on workflow were less likely to agree. While electronic referrals hold promise as a tool to improve clinical care, their impact on workflow should be considered

Energy Reallocation to Breeding Performance through Improved Nest Building in Laboratory Mice.

Mice are housed at temperatures (20-26°C) that increase their basal metabolic rates and impose high energy demands to maintain core temperatures. Therefore, energy must be reallocated from other biological processes to increase heat production to offset heat loss. Supplying laboratory mice with nesting material may provide sufficient insulation to reduce heat loss and improve both feed conversion and breeding performance. Naïve C57BL/6, BALB/c, and CD-1breeding pairs were provided with bedding alone, or bedding supplemented with either 8g of Enviro-Dri, 8g of Nestlets, for 6 months. Mice provided with either nesting material built more dome-like nests than controls. Nesting material improved feed efficiency per pup weaned as well as pup weaning weight. The breeding index (pups weaned/dam/week) was higher when either nesting material was provided. Thus, the sparing of energy for thermoregulation of mice given additional nesting material may have been responsible for the improved breeding and growth of offspring

Fosmidomycin Uptake into Plasmodium and Babesia-Infected Erythrocytes Is Facilitated by Parasite-Induced New Permeability Pathways

., a mouse malaria parasite. and related parasites. Our data provide further evidence that parasite-induced new permeability pathways may be exploited as routes for drug delivery

Facilitators and barriers to implementing electronic referral and/or consultation systems: a qualitative study of 16 health organizations

BACKGROUND: Access to specialty care remains a challenge for primary care providers and patients. Implementation of electronic referral and/or consultation (eCR) systems provides an opportunity for innovations in the delivery of specialty care. We conducted key informant interviews to identify drivers, facilitators, barriers and evaluation metrics of diverse eCR systems to inform widespread implementation of this model of specialty care delivery. METHODS: Interviews were conducted with leaders of 16 diverse health care delivery organizations between January 2013 and April 2014. A limited snowball sampling approach was used for recruitment. Content analysis was used to examine key informant interview transcripts. RESULTS: Electronic referral systems, which provide referral management and triage by specialists, were developed to enhance tracking and operational efficiency. Electronic consultation systems, which encourage bi-directional communication between primary care and specialist providers facilitating longitudinal virtual co-management, were developed to improve access to specialty expertise. Integrated eCR systems leverage both functionalities to enhance the delivery of coordinated, specialty care at the population level. Elements of successful eCR system implementation included executive and clinician leadership, established funding models for specialist clinician reimbursement, and a commitment to optimizing clinician workflows. CONCLUSIONS: eCR systems have great potential to streamline access to and enhance the coordination of specialty care delivery. While different eCR models help solve different organizational challenges, all require institutional investments for successful implementation, such as funding for program management, leadership and clinician incentives. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1186/s12913-015-1233-1) contains supplementary material, which is available to authorized users

Identification of Intracellular and Plasma Membrane Calcium Channel Homologues in Pathogenic Parasites

Ca2+ channels regulate many crucial processes within cells and their abnormal activity can be damaging to cell survival, suggesting that they might represent attractive therapeutic targets in pathogenic organisms. Parasitic diseases such as malaria, leishmaniasis, trypanosomiasis and schistosomiasis are responsible for millions of deaths each year worldwide. The genomes of many pathogenic parasites have recently been sequenced, opening the way for rational design of targeted therapies. We analyzed genomes of pathogenic protozoan parasites as well as the genome of Schistosoma mansoni, and show the existence within them of genes encoding homologues of mammalian intracellular Ca2+ release channels: inositol 1,4,5-trisphosphate receptors (IP3Rs), ryanodine receptors (RyRs), two-pore Ca2+ channels (TPCs) and intracellular transient receptor potential (Trp) channels. The genomes of Trypanosoma, Leishmania and S. mansoni parasites encode IP3R/RyR and Trp channel homologues, and that of S. mansoni additionally encodes a TPC homologue. In contrast, apicomplexan parasites lack genes encoding IP3R/RyR homologues and possess only genes encoding TPC and Trp channel homologues (Toxoplasma gondii) or Trp channel homologues alone. The genomes of parasites also encode homologues of mammalian Ca2+ influx channels, including voltage-gated Ca2+ channels and plasma membrane Trp channels. The genome of S. mansoni also encodes Orai Ca2+ channel and STIM Ca2+ sensor homologues, suggesting that store-operated Ca2+ entry may occur in this parasite. Many anti-parasitic agents alter parasite Ca2+ homeostasis and some are known modulators of mammalian Ca2+ channels, suggesting that parasite Ca2+ channel homologues might be the targets of some current anti-parasitic drugs. Differences between human and parasite Ca2+ channels suggest that pathogen-specific targeting of these channels may be an attractive therapeutic prospect

Civil society leadership in the struggle for AIDS treatment in South Africa and Uganda

Includes abstract.Includes bibliographical references.This thesis is an attempt to theorise and operationalise empirically the notion of ‘civil society leadership’ in Sub-Saharan Africa. ‘AIDS leadership,’ which is associated with the intergovernmental institutions charged with coordinating the global response to HIV/AIDS, is both under-theorised and highly context-specific. In this study I therefore opt for an inclusive framework that draws on a range of approaches, including the literature on ‘leadership’, institutions, social movements and the ‘network’ perspective on civil society mobilisation. This framework is employed in rich and detailed empirical descriptions (‘thick description’) of civil society mobilisation around AIDS, including contentious AIDS activism, in the key case studies of South Africa and Uganda. South Africa and Uganda are widely considered key examples of poor and good leadership (from national political leaders) respectively, while the Treatment Action Campaign (TAC) and The AIDS Support Organisation (TASO) are both seen as highly effective civil society movements. These descriptions emphasise ‘transnational networks of influence’ in which civil society leaders participated (and at times actively constructed) in order to mobilise both symbolic and material resources aimed at exerting influence at the transnational, national and local levels