1,289 research outputs found

    Developing a National-Level Concept Dictionary for EHR Implementations in Kenya

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    The increasing adoption of Electronic Health Records (EHR) by developing countries comes with the need to develop common terminology standards to assure semantic interoperability. In Kenya, where the Ministry of Health has rolled out an EHR at 646 sites, several challenges have emerged including variable dictionaries across implementations, inability to easily share data across systems, lack of expertise in dictionary management, lack of central coordination and custody of a terminology service, inadequately defined policies and processes, insufficient infrastructure, among others. A Concept Working Group was constituted to address these challenges. The country settled on a common Kenya data dictionary, initially derived as a subset of the Columbia International eHealth Laboratory (CIEL) / Millennium Villages Project (MVP) dictionary. The initial dictionary scope largely focuses on clinical needs. Processes and policies around dictionary management are being guided by the framework developed by Bakhshi-Raiez et al. Technical and infrastructure-based approaches are also underway to streamline workflow for dictionary management and distribution across implementations. Kenya's approach on comprehensive common dictionary can serve as a model for other countries in similar settings

    Homoleptic complexes of a porphyrinatozinc(II)-2,2’:6’,2’’-terpyridine ligand

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    Three homoleptic complexes containing the metalloligand 7-(4-([2,2′:6′,2′′-terpyridin]-4′-yl)phenyl)-5,10,15,20-tetraphenylporphyrinatozinc(II), 1, have been prepared. [Zn(1)2][PF6]2, [Fe(1)2][PF6]2 and [Ru(1)2][PF6]2 were characterized by 1H and 13C NMR spectroscopy and mass spectrometry, and the electrochemical and photophysical properties of the complexes have been investigated. In solution, each complex undergoes two reversible porphyrin-centred oxidation processes, with an additional reversible metal-centred oxidation for [Fe(1)2][PF6]2 and [Ru(1)2][PF6]2. Solution absorption spectra are dominated by the Soret and Q bands of the metalloligand 1. Spectroelectrochemical data for the complexes are presented. The results of a nanosecond transient absorption spectroscopic investigation of [Zn(1)2][PF6]2, [Fe(1)2][PF6]2 and [Ru(1)2][PF6]2 are presented. For [Zn(1)2][PF6]2, S1 excitation leads to an efficient intersystem-crossing to the T1 state, whilst for [Fe(1)2][PF6]2, excitation of the 1MLCT transition is followed by fast deactivation to the 3MC state followed by thermal decay to the ground state. Excitation of the 1MLCT transition of [Ru(1)2][PF6]2 results in an intersystem crossing to 3MLCT; triplet-to-triplet energy transfer occurs giving the [Zn(TPP)] T1 state which regenerates the ground state of the complex

    The Ionization Fraction in Dense Molecular Gas II: Massive Cores

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    We present an observational and theoretical study of the ionization fraction in several massive cores located in regions that are currently forming stellar clusters. Maps of the emission from the J = 1-> O transitions of C18O, DCO+, N2H+, and H13CO+, as well as the J = 2 -> 1 and J = 3 -> 2 transitions of CS, were obtained for each core. Core densities are determined via a large velocity gradient analysis with values typically 10^5 cm^-3. With the use of observations to constrain variables in the chemical calculations we derive electron fractions for our overall sample of 5 cores directly associated with star formation and 2 apparently starless cores. The electron abundances are found to lie within a small range, -6.9 < log10(x_e) < -7.3, and are consistent with previous work. We find no difference in the amount of ionization fraction between cores with and without associated star formation activity, nor is any difference found in electron abundances between the edge and center of the emission region. Thus our models are in agreement with the standard picture of cosmic rays as the primary source of ionization for molecular ions. With the addition of previously determined electron abundances for low mass cores, and even more massive cores associated with O and B clusters, we systematically examine the ionization fraction as a function of star formation activity. This analysis demonstrates that the most massive sources stand out as having the lowest electron abundances (x_e < 10^-8).Comment: 35 pages (8 figures), using aaspp4.sty, to be published in Astrophysical Journa

    Identification of synaptotagmin effectors via acute inhibition of secretion from cracked PC12 cells

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    T he synaptotagmins (syts) are a family of membrane proteins proposed to regulate membrane traffic in neuronal and nonneuronal cells. In neurons, the Ca2+-sensing ability of syt I is critical for fusion of docked synaptic vesicles with the plasma membrane in response to stimulation. Several putative Ca2+–syt effectors have been identified, but in most cases the functional significance of these interactions remains unknown. Here, we have used recombinant C2 domains derived from the cytoplasmic domains of syts I–XI to interfere with endogenous syt–effector interactions during Ca2+-triggered exocytosis from cracked PC12 cells. Inhibition was closely correlated with syntaxin–SNAP-25 and phosphatidylinositol 4,5-bisphosphate (PIP2)–binding activity. Moreover, we measured the expression levels of endogenous syts in PC12 cells; the major isoforms are I and IX, with trace levels of VII. As expected, if syts I and IX function as Ca2+ sensors, fragments from these isoforms blocked secretion. These data suggest that syts trigger fusion via their Ca2+-regulated interactions with t-SNAREs and PIP2, target molecules known to play critical roles in exocytosis

    The Lesioned Brain: Still a Small-World?

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    The intra-arterial amobarbital procedure (IAP or Wada test) is used to determine language lateralization and contralateral memory functioning in patients eligible for neurosurgery because of pharmaco-resistant epilepsy. During unilateral sedation, functioning of the contralateral hemisphere is assessed by means of neuropsychological tests. We use the IAP as a reversible model for the effect of lesions on brain network topology. Three artifact-free epochs (4096 samples) were selected from each electroencephalogram record before and after amobarbital injection. Functional connectivity was assessed by means of the synchronization likelihood. The resulting functional connectivity matrices were constructed for all six epochs per patient in four frequency bands, and weighted network analysis was performed. The clustering coefficient, average path length, small-world index, and edge weight correlation were calculated. Recordings of 33 patients were available. Network topology changed significantly after amobarbital injection: clustering decreased in all frequency bands, while path length decreased in the theta and lower alpha band, indicating a shift toward a more random network topology. Likewise, the edge weight correlation decreased after injection of amobarbital in the theta and beta bands. Network characteristics after injection of amobarbital were correlated with memory score: higher theta band small-world index and increased upper alpha path length were related to better memory score. The whole-brain network topology in patients eligible for epilepsy surgery becomes more random and less optimally organized after selective sedation of one hemisphere, as has been reported in studies with brain tumor patients. Furthermore, memory functioning after injection seems related to network topology, indicating that functional performance is related to topological network properties of the brain

    Oscillatory Modes of a Prominence-PCTR-Corona Slab Model

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    Oscillations of magnetic structures in the solar corona have often been interpreted in terms of magnetohydrodynamic waves. We study the adiabatic magnetoacoustic modes of a prominence plasma slab with a uniform longitudinal magnetic field, surrounded by a prominence-corona transition region (PCTR) and a coronal medium. Considering linear small-amplitude oscillations, the dispersion relation for the magnetoacoustic slow and fast modes is deduced assuming evanescent-like perturbations in the coronal medium. In the system without PCTR, a classification of the oscillatory modes according to the polarisation of their eigenfunctions is made in order to distinguish modes with fast-like or slow-like properties. Internal and external slow modes are governed by the prominence and coronal properties respectively, and fast modes are mostly dominated by prominence conditions for the observed wavelengths. In addition, the inclusion of an isothermal PCTR does not substantially influence the mode frequencies, but new solutions (PCTR slow modes) are present.Comment: Accepted for publication in Solar Physic

    Reduction in oxidatively generated DNA damage following smoking cessation

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    <p>Abstract</p> <p>Background</p> <p>Cigarette smoking is a known cause of cancer, and cancer may be in part due to effects of oxidative stress. However, whether smoking cessation reverses oxidatively induced DNA damage unclear. The current study sought to examine the extent to which three DNA lesions showed significant reductions after participants quit smoking.</p> <p>Methods</p> <p>Participants (n = 19) in this study were recruited from an ongoing 16-week smoking cessation clinical trial and provided blood samples from which leukocyte DNA was extracted and assessed for 3 DNA lesions (thymine glycol modification [d(T<sup>g</sup>pA)]; formamide breakdown of pyrimidine bases [d(T<sup>g</sup>pA)]; 8-oxo-7,8-dihydroguanine [d(G<sup>h</sup>)]) via liquid chromatography tandem mass spectrometry (LC-MS/MS). Change in lesions over time was assessed using generalized estimating equations, controlling for gender, age, and treatment condition.</p> <p>Results</p> <p>Overall time effects for the d(T<sup>g</sup>pA) (χ<sup>2</sup>(3) = 8.068, p < 0.045), d(P<sup>f</sup>pA) (χ<sup>2</sup>(3) = 8.477, p < 0.037), and d(G<sup>h</sup>) (χ<sup>2</sup>(3) = 37.599, p < 0.001) lesions were seen, indicating levels of each decreased significantly after CO-confirmed smoking cessation. The d(T<sup>g</sup>pA) and d(P<sup>f</sup>pA) lesions show relatively greater rebound at Week 16 compared to the d(G<sup>h</sup>) lesion (88% of baseline for d(T<sup>g</sup>pA), 64% of baseline for d(P<sup>f</sup>pA), vs 46% of baseline for d(G<sup>h</sup>)).</p> <p>Conclusions</p> <p>Overall, results from this analysis suggest that cigarette smoking contributes to oxidatively induced DNA damage, and that smoking cessation appears to reduce levels of specific damage markers between 30-50 percent in the short term. Future research may shed light on the broader array of oxidative damage influenced by smoking and over longer durations of abstinence, to provide further insights into mechanisms underlying carcinogenesis.</p

    Hot, metastable hydronium ion in the Galactic center: Formation pumping in X-ray irradiated gas?

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    With a 3.5-meter diameter telescope passively cooled to ∼80 K and a science payload comprising two direct detection cameras/medium resolution imaging spectrometers, PACS and SPIRE, and a very high spectral resolution heterodyne spectrometer, HIFI, the Herschel Space Observatory is providing extraordinary observational opportunities in the 55-670 µm spectral range. HIFI has opened for the first time to high-resolution spectroscopy the submillimeter band that includes the fundamental rotational transitions of interstellar hydrides, the basic building blocks of astrochemistry. We discuss a recent HIFI discovery of metastable rotational transitions of the hydronium ion (protonated water, H 3 O + ), with rotational level energies up to 1200 K above the ground state, in absorption towards Sagittarius B2(N) in the Galactic center. Hydronium is an important molecular ion in the oxygen chemical network. Earlier HIFI observations have indicated a general deficiency of H 3 O + in the diffuse gas in the Galactic disk. The presence of hot H 3 O + towards Sagittarius B2(N) thus appears to be related to the unique physical conditions and the widespread presence of abundant H + 3 in the Central Molecular Zone. The high rotational temperature characterizing the population of the metastable levels may be indicative of H 3 O + formation pumping in molecular gas irradiated by X-rays emitted by the Galactic center black hole

    Implementing Silicon Nanoribbon Field-Effect Transistors as Arrays for Multiple Ion Detection

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    Ionic gradients play a crucial role in the physiology of the human body, ranging from metabolism in cells to muscle contractions or brain activities. To monitor these ions, inexpensive, label-free chemical sensing devices are needed. Field-effect transistors (FETs) based on silicon (Si) nanowires or nanoribbons (NRs) have a great potential as future biochemical sensors as they allow for the integration in microscopic devices at low production costs. Integrating NRs in dense arrays on a single chip expands the field of applications to implantable electrodes or multifunctional chemical sensing platforms. Ideally, such a platform is capable of detecting numerous species in a complex analyte. Here, we demonstrate the basis for simultaneous sodium and fluoride ion detection with a single sensor chip consisting of arrays of gold-coated SiNR FETs. A microfluidic system with individual channels allows modifying the NR surfaces with self-assembled monolayers of two types of ion receptors sensitive to sodium and fluoride ions. The functionalization procedure results in a differential setup having active fluoride-and sodium-sensitive NRs together with bare gold control NRs on the same chip. Comparing functionalized NRs with control NRs allows the compensation of non-specific contributions from changes in the background electrolyte concentration and reveals the response to the targeted species

    Herschel observations of EXtraordinary Sources: Analysis of the full Herschel/HIFI molecular line survey of Sagittarius B2(N)

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    A sensitive broadband molecular line survey of the Sagittarius B2(N) star-forming region has been obtained with the HIFI instrument on the Herschel Space Observatory, offering the first high-spectral resolution look at this well-studied source in a wavelength region largely inaccessible from the ground (625-157 um). From the roughly 8,000 spectral features in the survey, a total of 72 isotopologues arising from 44 different molecules have been identified, ranging from light hydrides to complex organics, and arising from a variety of environments from cold and diffuse to hot and dense gas. We present an LTE model to the spectral signatures of each molecule, constraining the source sizes for hot core species with complementary SMA interferometric observations, and assuming that molecules with related functional group composition are cospatial. For each molecule, a single model is given to fit all of the emission and absorption features of that species across the entire 480-1910 GHz spectral range, accounting for multiple temperature and velocity components when needed to describe the spectrum. As with other HIFI surveys toward massive star forming regions, methanol is found to contribute more integrated line intensity to the spectrum than any other species. We discuss the molecular abundances derived for the hot core, where the local thermodynamic equilibrium approximation is generally found to describe the spectrum well, in comparison to abundances derived for the same molecules in the Orion KL region from a similar HIFI survey.Comment: Accepted to ApJ. 64 pages, 14 figures. Truncated abstrac
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