9,383 research outputs found

    Preparation and characterization of methacrylate hydrogels for zeta potential control

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    A technique based on the measurement of streaming potentials has been developed to evaluate the effects of hydrophilic coatings on electroosmotic flow. The apparatus and procedure are described as well as some results concerning the electrokinetic potential of glass capillaries as a function of ionic strength, pH, and temperature. The effect that turbulence and entrance flow conditions have on accurate streaming potential measurements is discussed. Various silane adhesion promoters exhibited only a slight decrease in streaming potential. A coating utilizing a glycidoxy silane base upon which methylcellulose is applied affords a six-fold decrease over uncoated tubes. Hydrophilic methacrylate gels show similar streaming potential behavior, independent of the water content of the gel. By introduction of positive or negative groups into the hydrophilic methacrylate gels, a range of streaming potential values are obtained having absolute positive or negative signs

    Hydrodynamics: Fluctuating Initial Conditions and Two-particle Correlations

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    Event-by-event hydrodynamics (or hydrodynamics with fluctuating initial conditions) has been developed in the past few years. Here we discuss how it may help to understand the various structures observed in two-particle correlations.Comment: 7 pages, 9 figures, presented at the Workshop on Saturation, the Color Glass Condensate and Glasma: What Have we Learned from RHIC

    Imaging the postoperative patient: long-term complications of gastrointestinal surgery

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    The objectives of this review are (1) to become acquainted with the long-term complications of surgery of the gastrointestinal tract, and (2) to appreciate the appropriate use of imaging in the assessment of long-term complications

    Aeroallergens sensitization in an allergic paediatric population of Cova da Beira, Portugal.

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    Cova da Beira is an interior central region of Portugal, with a population of 93,000 inhabitants. The first pollen counts performed in Portugal revealed the highest values of the country in this area. The aim of this study was to assess the aeroallergens sensitization in an allergic population, according to the age groups. In a 5 year period (1995-2000) 1790 consecutive outpatients were observed for suspected allergic symptoms. We included in this study all the 557 paediatric (< or = 15 years old) observed patients (317 male (57%) and 240 female (43%) with an average age of 7.6 < or = 4.2 years old). They were divided in three age groups (Group I: < or = 5 yr; Group II: 6-10 yr; Group III: 11-15 yr). 371 patients were submitted to skin prick tests to aeroallergens. 86.5% of these patients were sensitised to at least one allergen extract. The most representative aeroallergens sensitization were grasses mixture (44.9%), D. pteronyssinus (32.5%), D. farinae (29.1%), Olea europea (27.5%), Parietaria judaica (23.4%), cat dander (16.1%), Artemisia vulgaris (17.6%), Robinia pseudoacacia (12.2%), Platanus acerifolia (11.4%), Tilia cordata (11.4%) moulds mixture (11.2%), Plantago lanceolata (10.6%), dog dander (10.4%), and Pinus radiata (7.5%). The sensitisation to indoor aeroallergens, was similar in all age groups and it was less important than that of pollens. The prevalence of sensitisation to grasses was the greatest in all ages and the house dust mites sensitization was the second most prevalent. The highest pollens counts in this region could explain the early sensitisation even in young children

    Design and rationale of a multi-center, pragmatic, open-label randomized trial of antimicrobial therapy - the study of clinical efficacy of antimicrobial therapy strategy using pragmatic design in Idiopathic Pulmonary Fibrosis (CleanUP-IPF) clinical trial

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    Compelling data have linked disease progression in patients with idiopathic pulmonary fibrosis (IPF) with lung dysbiosis and the resulting dysregulated local and systemic immune response. Moreover, prior therapeutic trials have suggested improved outcomes in these patients treated with either sulfamethoxazole/ trimethoprim or doxycycline. These trials have been limited by methodological concerns. This trial addresses the primary hypothesis that long-term treatment with antimicrobial therapy increases the time-to-event endpoint of respiratory hospitalization or all-cause mortality compared to usual care treatment in patients with IPF. We invoke numerous innovative features to achieve this goal, including: 1) utilizing a pragmatic randomized trial design; 2) collecting targeted biological samples to allow future exploration of 'personalized' therapy; and 3) developing a strong partnership between the NHLBI, a broad range of investigators, industry, and philanthropic organizations. The trial will randomize approximately 500 individuals in a 1:1 ratio to either antimicrobial therapy or usual care. The site principal investigator will declare their preferred initial antimicrobial treatment strategy (trimethoprim 160 mg/ sulfamethoxazole 800 mg twice a day plus folic acid 5 mg daily or doxycycline 100 mg once daily if body weight is < 50 kg or 100 mg twice daily if ≥50 kg) for the participant prior to randomization. Participants randomized to antimicrobial therapy will receive a voucher to help cover the additional prescription drug costs. Additionally, those participants will have 4-5 scheduled blood draws over the initial 24 months of therapy for safety monitoring. Blood sampling for DNA sequencing and genome wide transcriptomics will be collected before therapy. Blood sampling for transcriptomics and oral and fecal swabs for determination of the microbiome communities will be collected before and after study completion. As a pragmatic study, participants in both treatment arms will have limited in-person visits with the enrolling clinical center. Visits are limited to assessments of lung function and other clinical parameters at time points prior to randomization and at months 12, 24, and 36. All participants will be followed until the study completion for the assessment of clinical endpoints related to hospitalization and mortality events. TRIAL REGISTRATION: ClinicalTrials.gov identifier NCT02759120

    Structure and Function of a Mycobacterial NHEJ DNA Repair Polymerase

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    Non homologous end-joining (NHEJ)-mediated repair of DNA double-strand breaks in prokaryotes requires Ku and a specific multidomain DNA ligase (LigD). We present crystal structures of the primase/polymerisation domain (PolDom) of Mycobacterium tuberculosis LigD, alone and complexed with nucleotides. The PolDom structure combines the general fold of the archaeo-eukaryotic primase (AEP) superfamily with additional loops and domains that together form a deep cleft on the surface, likely used for DNA binding. Enzymatic analysis indicates that the PolDom of LigD, even in the absence of accessory domains and Ku proteins, has the potential to recognise DNA end-joining intermediates. Strikingly, one of the main signals for the specific and efficient binding of PolDom to DNA is the presence of a 5'-phosphate group, located at the single/double-stranded junction at both gapped and 3'-protruding DNA molecules. Although structurally unrelated, Pol lambda and Pol mu, the two eukaryotic DNA polymerases involved in NHEJ, are endowed with a similar capacity to bind a 5'-phosphate group. Other properties that are beneficial for NHEJ, such as the ability to generate template distortions and realignments of the primer, displayed by Pol lambda and Pol mu, are shared by the PolDom of bacterial LigD. In addition, PolDom can perform non-mutagenic translesion synthesis on termini containing modified bases. Significantly, ribonucleotide insertion appears to be a recurrent theme associated with NHEJ, maximised in this case by the deployment of a dedicated primase, although its in vivo relevance is unknown

    Stochastic Renormalization Group in Percolation: I. Fluctuations and Crossover

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    A generalization of the Renormalization Group, which describes order-parameter fluctuations in finite systems, is developed in the specific context of percolation. This ``Stochastic Renormalization Group'' (SRG) expresses statistical self-similarity through a non-stationary branching process. The SRG provides a theoretical basis for analytical or numerical approximations, both at and away from criticality, whenever the correlation length is much larger than the lattice spacing (regardless of the system size). For example, the SRG predicts order-parameter distributions and finite-size scaling functions for the complete crossover between phases. For percolation, the simplest SRG describes structural quantities conditional on spanning, such as the total cluster mass or the minimum chemical distance between two boundaries. In these cases, the Central Limit Theorem (for independent random variables) holds at the stable, off-critical fixed points, while a ``Fractal Central Limit Theorem'' (describing long-range correlations) holds at the unstable, critical fixed point. This first part of a series of articles explains these basic concepts and a general theory of crossover. Subsequent parts will focus on limit theorems and comparisons of small-cell SRG approximations with simulation results.Comment: 33 pages, 6 figures, to appear in Physica A; v2: some typos corrected and Eqs. (26)-(27) cast in a simpler (but equivalent) for

    An Efficient Local Search for Partial Latin Square Extension Problem

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    A partial Latin square (PLS) is a partial assignment of n symbols to an nxn grid such that, in each row and in each column, each symbol appears at most once. The partial Latin square extension problem is an NP-hard problem that asks for a largest extension of a given PLS. In this paper we propose an efficient local search for this problem. We focus on the local search such that the neighborhood is defined by (p,q)-swap, i.e., removing exactly p symbols and then assigning symbols to at most q empty cells. For p in {1,2,3}, our neighborhood search algorithm finds an improved solution or concludes that no such solution exists in O(n^{p+1}) time. We also propose a novel swap operation, Trellis-swap, which is a generalization of (1,q)-swap and (2,q)-swap. Our Trellis-neighborhood search algorithm takes O(n^{3.5}) time to do the same thing. Using these neighborhood search algorithms, we design a prototype iterated local search algorithm and show its effectiveness in comparison with state-of-the-art optimization solvers such as IBM ILOG CPLEX and LocalSolver.Comment: 17 pages, 2 figure

    The Noncommutative Harmonic Oscillator based in Simplectic Representation of Galilei Group

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    In this work we study symplectic unitary representations for the Galilei group. As a consequence the Schr\"odinger equation is derived in phase space. The formalism is based on the non-commutative structure of the star-product, and using the group theory approach as a guide a physical consistent theory in phase space is constructed. The state is described by a quasi-probability amplitude that is in association with the Wigner function. The 3D harmonic oscillator and the noncommutative oscillator are studied in phase space as an application, and the Wigner function associated to both cases are determined.Comment: 7 pages,no figure

    Perspectives on the Trypanosoma cruzi-host cell receptor interaction

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    Chagas disease is caused by the parasite Trypanosoma cruzi. The critical initial event is the interaction of the trypomastigote form of the parasite with host receptors. This review highlights recent observations concerning these interactions. Some of the key receptors considered are those for thromboxane, bradykinin, and for the nerve growth factor TrKA. Other important receptors such as galectin-3, thrombospondin, and laminin are also discussed. Investigation into the molecular biology and cell biology of host receptors for T. cruzi may provide novel therapeutic targets
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