Uganda's "EID Systems Strengthening" model produces significant gains in testing, linkage, and retention of HIV-exposed and infected infants: An impact evaluation.

INTRODUCTION: A review of Uganda's HIV Early Infant Diagnosis (EID) program in 2010 revealed poor retention outcomes for HIV-exposed infants (HEI) after testing. The review informed development of the 'EID Systems Strengthening' model: a set of integrated initiatives at health facilities to improve testing, retention, and clinical care of HIV-exposed and infected infants. The program model was piloted at several facilities and later scaled countrywide. This mixed-methods study evaluates the program's impact and assesses its implementation. METHODS: We conducted a retrospective cohort study at 12 health facilities in Uganda, comprising all HEI tested by DNA PCR from June 2011 to May 2014 (n = 707). Cohort data were collected manually at the health facilities and analyzed. To assess impact, retention outcomes were statistically compared to the baseline study's cohort outcomes. We conducted a cross-sectional qualitative assessment of program implementation through 1) structured clinic observation and 2) key informant interviews with health workers, district officials, NGO technical managers, and EID trainers (n = 51). RESULTS: The evaluation cohort comprised 707 HEI (67 HIV+). The baseline study cohort contained 1268 HEI (244 HIV+). Among infants testing HIV+, retention in care at an ART clinic increased from 23% (57/244) to 66% (44/67) (p < .0001). Initiation of HIV+ infants on ART increased from 36% (27/75) to 92% (46/50) (p < .0001). HEI receiving 1st PCR results increased from 57% (718/1268) to 73% (518/707) (p < .0001). Among breastfeeding HEI with negative 1st PCR, 55% (192/352) received a confirmatory PCR test, a substantial increase from baseline period. Testing coverage improved significantly: HIV+ pregnant women who brought their infants for testing after birth increased from 18% (67/367) to 52% (175/334) (p < .0001). HEI were tested younger: mean age at DBS test decreased from 6.96 to 4.21 months (p < .0001). Clinical care for HEI was provided more consistently. Implementation fidelity was strong for most program components. The strongest contributory interventions were establishment of 'EID Care Points', integration of clinical care, longitudinal patient tracking, and regular health worker mentorship. Gaps included limited follow up of lost infants, inconsistent buy-in/ownership of health facility management, and challenges sustaining health worker motivation. DISCUSSION: Uganda's 'EID Systems Strengthening' model has produced significant gains in testing and retention of HEI and HIV+ infants, yet the country still faces major challenges. The 3 core concepts of Uganda's model are applicable to any country: establish a central service point for HEI, equip it to provide high-quality care and tracking, and develop systems to link HEI to the service point. Uganda's experience has shown the importance of intensively targeting systemic bottlenecks to HEI retention at facility level, a necessary complement to deploying rapidly scalable technologies and other higher-level initiatives.

Probing embedded topological modes in bulk-like GeTe-Sb2Te3 heterostructures.

The interface between topological and normal insulators hosts metallic states that appear due to the change in band topology. While topological states at a surface, i.e., a topological insulator-air/vacuum interface, have been studied intensely, topological states at a solid-solid interface have been less explored. Here we combine experiment and theory to study such embedded topological states (ETSs) in heterostructures of GeTe (normal insulator) and [Formula: see text] [Formula: see text] (topological insulator). We analyse their dependence on the interface and their confinement characteristics. First, to characterise the heterostructures, we evaluate the GeTe-Sb[Formula: see text]Te[Formula: see text] band offset using X-ray photoemission spectroscopy, and chart the elemental composition using atom probe tomography. We then use first-principles to independently calculate the band offset and also parametrise the band structure within a four-band continuum model. Our analysis reveals, strikingly, that under realistic conditions, the interfacial topological modes are delocalised over many lattice spacings. In addition, the first-principles calculations indicate that the ETSs are relatively robust to disorder and this may have practical ramifications. Our study provides insights into how to manipulate topological modes in heterostructures and also provides a basis for recent experimental findings [Nguyen et al. Sci. Rep. 6, 27716 (2016)] where ETSs were seen to couple over thick layers.

"If I had known, I would have applied": poor communication, job dissatisfaction, and attrition of rural health workers in Sierra Leone.

BACKGROUND: Sierra Leone's health outcomes rank among the worst in the world. A major challenge is the shortage of primary healthcare workers (HCWs) in rural areas due to especially high rates of attrition. This study was undertaken to determine the drivers of job dissatisfaction and poor retention among Sierra Leone's rural HCWs. METHODS: Interviews were conducted with 58 rural and 32 urban primary HCWs in Sierra Leone's public health sector, complemented by key informant discussions and review of national policy documents. HCW interviews included (1) semi-structured discussion, (2) questionnaire, (3) card sort about HCW priorities, and (4) free-listing of most pressing challenges and needs. Sampling for HCW interviews was stratified purposive, emphasizing rural HCWs. RESULTS: Among 90 HCWs interviewed, 67% were dissatisfied with their jobs (71% rural vs 52% urban) and 61% intended to leave their post (75% rural vs 38% urban). While working and living conditions and remuneration were significant factors, a major reason for rural HCW disenchantment was their inability to access worker rights, benefits, and advancement opportunities. This was caused by HCWs' lack of knowledge about human resource (HR) policies and procedures, as well as ambiguity in many policies and inequitable implementation. HCWs reported feeling neglected and marginalized and perceived a lack of transparency. These issues can be attributed to the absence of systems for regular two-way communication between the Ministry of Health and HCWs; lack of official national documents with up-to-date, clear HR policies and procedures for HCWs; pay statements that do not provide a breakdown of financial allowances and withholdings; and lack of HCW induction. CONCLUSIONS: HCWs in Sierra Leone lacked accurate information about entitlements, policies, and procedures, and this was a driver of rural HCW job dissatisfaction and attrition. System-oriented, low-cost initiatives can address these underlying structural causes in Sierra Leone. These issues likely apply to other countries facing HCW retention challenges and should be considered in development of global HCW retention strategies.

Retention outcomes and drivers of loss among HIV-exposed and infected infants in Uganda: a retrospective cohort study.

BACKGROUND: Uganda's HIV Early Infant Diagnosis (EID) program rapidly scaled up testing of HIV-exposed infants (HEI) in its early years. However, little was known about retention outcomes of HEI after testing. Provision of transport refunds to HEI caregivers was piloted at 3 hospitals to improve retention. This study was conducted to quantify retention outcomes of tested HEI, identify factors driving loss-to-follow-up, and assess the effect of transport refunds on HEI retention. METHODS: This mixed-methods study included 7 health facilities- retrospective cohort review at 3 hospitals and qualitative assessment at all facilities. The cohort comprised all HEI tested from September-2007 to February-2009. Retention data was collected manually at each hospital. Qualitative methods included health worker interviews and structured clinic observation. Qualitative data was synthesized, analyzed and triangulated to identify factors driving HEI loss-to-follow-up. RESULTS: The cohort included 1268 HEI, with 244 testing HIV-positive. Only 57% (718/1268) of tested HEI received results. The transport refund pilot increased the percent of HEI caregivers receiving test results from 54% (n = 763) to 58% (n = 505) (p = .08). HEI were tested at late ages (Mean = 7.0 months, n = 1268). Many HEI weren't tested at all: at 1 hospital, only 18% (67/367) of HIV+ pregnant women brought their HEI for testing after birth. Among HIV+ infants, only 40% (98/244) received results and enrolled at an ART Clinic. Of enrolled HIV+ infants, only 43% (57/98) were still active in chronic care. 36% (27/75) of eligible HIV+ infants started ART. Our analysis identified 6 categories of factors driving HEI loss-to-follow-up: fragmentation of EID services across several clinics, with most poorly equipped for HEI care/follow-up; poor referral mechanisms and data management systems; inconsistent clinical care; substandard counseling; poor health worker knowledge of EID; long sample-result turnaround times. DISCUSSION: The poor outcomes for HEI and HIV+ infants have highlighted an urgent need to improve retention and linkage to care. To address the identified gaps, Uganda's Ministry of Health and the Clinton Health Access Initiative developed a new implementation model, shifting EID from a lab-based diagnostic service to an integrated clinic-based chronic care model. This model was piloted at 21 facilities. An evaluation is needed.

Fully Printed Organic-Inorganic Nanocomposites for Flexible Thermoelectric Applications.

Thermoelectric materials, capable of interconverting heat and electricity, are attractive for applications in thermal energy harvesting as a means to power wireless sensors, wearable devices, and portable electronics. However, traditional inorganic thermoelectric materials pose significant challenges due to high cost, toxicity, scarcity, and brittleness, particularly when it comes to applications requiring flexibility. Here, we investigate organic-inorganic nanocomposites that have been developed from bespoke inks which are printed via an aerosol jet printing method onto flexible substrates. For this purpose, a novel in situ aerosol mixing method has been developed to ensure uniform distribution of Bi2Te3/Sb2Te3 nanocrystals, fabricated by a scalable solvothermal synthesis method, within a poly(3,4-ethylenedioxythiophene) polystyrene sulfonate matrix. The thermoelectric properties of the resulting printed nanocomposite structures have been evaluated as a function of composition, and the power factor was found to be maximum (∼30 µW/mK2) for a nominal loading fraction of 85 wt % Sb2Te3 nanoflakes. Importantly, the printed nanocomposites were found to be stable and robust upon repeated flexing to curvatures up to 300 m-1, making these hybrid materials particularly suitable for flexible thermoelectric applications.

Structure and Thermoelectric Properties of Bi2-xSbxTe3 Nanowires Grown in Flexible Nanoporous Polycarbonate Templates.

We report the room-temperature growth of vertically aligned ternary Bi2-xSbxTe3 nanowires of diameter ~200 nm and length ~12 µm, within flexible track-etched nanoporous polycarbonate (PC) templates via a one-step electrodeposition process. Bi2-xSbxTe3 nanowires with compositions spanning the entire range from pure Bi2Te3 (x = 0) to pure Sb2Te3 (x = 2) were systematically grown within the nanoporous channels of PC templates from a tartaric-nitric acid based electrolyte, at the end of which highly crystalline nanowires of uniform composition were obtained. Compositional analysis showed that the Sb concentration could be tuned by simply varying the electrolyte composition without any need for further annealing of the samples. Thermoelectric properties of the Bi2-xSbxTe3 nanowires were measured using a standardized bespoke setup while they were still embedded within the flexible PC templates.

Reappearance of linear hole transport in an ambipolar undoped GaAs/AlGaAs quantum well.

We report the results of an investigation of ambipolar transport in a quantum well of 15 nm width in an undoped GaAs/AlGaAs structure, which was populated either by electrons or holes using positive or negative gate voltage V tg, respectively. More attention was focussed on the low concentration of electrons n and holes p near the metal-insulator transition (MIT). It is shown that the electron mobility [Formula: see text] increases almost linearly with increase of n and is independent of temperature T in the interval 0.3 K-1.4 K, while the hole mobility [Formula: see text] depends non-monotonically on p and T. This difference is explained on the basis of the different effective masses of electrons and holes in GaAs. Intriguingly, we observe that at low p the source-drain current (I SD)-voltage (V) characteristics, which become non-linear beyond a certain I SD, exhibit a re-entrant linear regime at even higher I SD. We find, remarkably, that the departure and reappearance of linear behaviour are not due to non-linear response of the system, but due to an intrinsic mechanism by which there is a reduction in the net number of mobile carriers. This effect is interpreted as evidence of inhomogeneity of the conductive 2D layer in the vicinity of MIT and trapping of holes in 'dead ends' of insulating islands. Our results provide insights into transport mechanisms as well as the spatial structure of the 2D conducting medium near the 2D MIT.

Topological states and phase transitions in Sb2Te3-GeTe multilayers.

Topological insulators (TIs) are bulk insulators with exotic 'topologically protected' surface conducting modes. It has recently been pointed out that when stacked together, interactions between surface modes can induce diverse phases including the TI, Dirac semimetal, and Weyl semimetal. However, currently a full experimental understanding of the conditions under which topological modes interact is lacking. Here, working with multilayers of the TI Sb2Te3 and the band insulator GeTe, we provide experimental evidence of multiple topological modes in a single Sb2Te3-GeTe-Sb2Te3 structure. Furthermore, we show that reducing the thickness of the GeTe layer induces a phase transition from a Dirac-like phase to a gapped phase. By comparing different multilayer structures we demonstrate that this transition occurs due to the hybridisation of states associated with different TI films. Our results demonstrate that the Sb2Te3-GeTe system offers strong potential towards manipulating topological states as well as towards controlledly inducing various topological phases.

'Metal'-like transport in high-resistance, high aspect ratio two-dimensional electron gases.

We investigate the striking absence of strong localisation observed in mesoscopic two-dimensional electron gases (2DEGs) (Baenninger et al 2008 Phys. Rev. Lett. 100 016805, Backes et al 2015 arXiv:1505.03444) even when their resistivity [Formula: see text]. In particular, we try to understand whether this phenomenon originates in quantum many-body effects, or simply percolative transport through a network of electron puddles. To test the latter scenario, we measure the low temperature (low-T) transport properties of long and narrow 2DEG devices in which percolation effects should be heavily suppressed in favour of Coulomb blockade. Strikingly we find no indication of Coulomb blockade and that the high-ρ, low-T transport is exactly similar to that previously reported in mesoscopic 2DEGs with different geometries. Remarkably, we are able to induce a 'metal'-insulator transition (MIT) by applying a perpendicular magnetic field B. We present a picture within which these observations fit into the more conventional framework of the 2D MIT.

Consolidating HIV testing in a public health laboratory for efficient and sustainable early infant diagnosis (EID) in Uganda.

Uganda introduced an HIV Early Infant Diagnosis (EID) program in 2006, and then worked to improve the laboratory, transportation, and clinical elements. Reported here are the activities involved in setting up a prospective analysis in which the Ministry of Health, with its NGO partners, determined it would be more effective and efficient to consolidate the initial eight-laboratory system for EID testing of HIV dried blood samples offered by two nongovernmental partners operating research facilities into a single well-equipped and staffed laboratory within the Ministry. A retrospective analysis confirmed that redesign reduced overhead cost per PCR test of HIV dried blood samples from US$22.20 to an average of $5. Along with the revamped system of sample collection, transportation, and result communication, Uganda has been able to vastly increase the HIV diagnosis of babies and engagement of them and their mothers in clinical care, including antiretroviral therapy. Uganda reduced turnaround times for results reporting to clinicians from more than a month in 2006 to just 2 weeks by 2014, even as samples tested increased dramatically. The next challenge is overcoming loss of babies and mothers to follow up.

Uganda's new national laboratory sample transport system: a successful model for improving access to diagnostic services for Early Infant HIV Diagnosis and other programs.

INTRODUCTION: Uganda scaled-up Early HIV Infant Diagnosis (EID) when simplified methods for testing of infants using dried blood spots (DBS) were adopted in 2006 and sample transport and management was therefore made feasible in rural settings. Before this time only 35% of the facilities that were providing EID services were reached through the national postal courier system, Posta Uganda. The transportation of samples during this scale-up, therefore, quickly became a challenge and varied from facility to facility as different methods were used to transport the samples. This study evaluates a novel specimen transport network system for EID testing. METHODS: A retrospective study was done in mid-2012 on 19 pilot hubs serving 616 health facilities in Uganda. The effect on sample-result turnaround time (TAT) and the cost of DBS sample transport on 876 sample-results was analyzed. RESULTS: The HUB network system provided increased access to EID services ranging from 36% to 51%, drastically reduced transportation costs by 62%, reduced turn-around times by 46.9% and by a further 46.2% through introduction of SMS printers. CONCLUSIONS: The HUB model provides a functional, reliable and efficient national referral network against which other health system strengthening initiatives can be built to increase access to critical diagnostic and treatment monitoring services, improve the quality of laboratory and diagnostic services, with reduced turn-around times and improved quality of prevention and treatment programs thereby reducing long-term costs.

Long-lived giant number fluctuations in a swarming granular nematic.

Coherently moving flocks of birds, beasts, or bacteria are examples of living matter with spontaneous orientational order. How do these systems differ from thermal equilibrium systems with such liquid crystalline order? Working with a fluidized monolayer of macroscopic rods in the nematic liquid crystalline phase, we find giant number fluctuations consistent with a standard deviation growing linearly with the mean, in contrast to any situation where the central limit theorem applies. These fluctuations are long-lived, decaying only as a logarithmic function of time. This shows that flocking, coherent motion, and large-scale inhomogeneity can appear in a system in which particles do not communicate except by contact.