22 research outputs found

    Structure, phase transformations, and defects of HfO₂ and ZrO₂ nanoparticles studied by ^(181)Ta and ^(111)Cd perturbed angular correlations, ^(1) H magic-angle spinning NMR, XPS, and x-ray and electron diffraction

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    Structure, phase transformations, grain growth, and defects of bare and alumina-coated nanoparticles of HfO₂ and ZrO₂ synthesized in a microwave-plasma process have been investigated by x-ray diffraction (XRD), transmission electron microscopy (TEM), and perturbed angular correlation (PAC) spectroscopy. The PAC technique was used to measure the electric quadrupole interactions (QIs) of the nuclear probes ^(181)Ta and ^(111)Cd in nanocrystalline HfO₂ and ZrO₂ as a function of temperature. For comparison, the QI of ^(181)Ta in the bulk oxides was determined in the same temperature range 300 K ≀ T ≀ 1550 K. The oxygen-metal ratio of the as- ynthesized particles was determined by x-ray photoelectron spectroscopy to be in the range 1.4 ≀ x ≀ 1.8. A hydrate surface layer with a hydrogen content of 5–10 wt %, consisting of chemisorbed hydroxyl groups and organic precursor fragments, was detected by ^(1) H magic-angle spinning NMR. XRD and TEM show that bare n-ZrO₂, Al₂O₃-coated n-ZrO₂, and Al₂O₃-coated n-HfO₂ are synthesized in the tetragonal or cubic modification with a particle size d < 5 nm, whereas bare n-HfO₂ is mainly monoclinic. The grain growth activation enthalpy of bare n-ZrO₂ is Q_(A)=32(5)kJ/mol. Coating with Al₂O₃ stabilizes the tetragonal over the monoclinic phase, both in hafnia and zirconia nanoparticles. While TEM micrographs of the native nanoparticles reveal a well-ordered cation sublattice, the observation of a broad QI distribution in the PAC spectra suggests a high degree of disorder of the oxygen sublattice. The gradual transformation of the disordered state and the phase evolution were studied by high-temperature QI measurements. Hafnia nanoparticles persist in the monoclinic (m) phase up to T ≀ 1400 K. In coated n-ZrO₂ /Al₂O₃, the monoclinic and tetragonal (t) phases coexist over a large temperature range, whereas uncoated, initially tetragonal or cubic (t or c) n-ZrO₂ presents a sharp m↔t transition. A “defect” component involving 30%–40% of the probe nuclei appears in the ^(181)Ta PAC spectra of all nanoparticles when these are cooled from high temperatures T ≄ 1200 K. The temperature dependence of this component can be reproduced by assuming that Ta impurities in hafnia and zirconia may trap electrons at low temperatures. The observation that the defect component appears only in nanoparticles with diameter d < 100 nm suggests that mobile electrons are available only in the surface region of the oxide particles, either from oxygen vacancies (Vo) and/or Vo- hydrogen donors at the interface of the nanoparticles and their hydrate layers. This conclusion is supported by the absence of a size effect for ^(111)Cd probes in HfO₂ and ZrO₂. The temperature dependence of the ^(181)Ta defect fraction is consistent with a Ta_(+) impurity level at E_d ~ 0.9 and 0.6 eV below the hafnia and zirconia conduction band, respectively

    Dual checkpoint blockade of CD47 and LILRB1 enhances CD20 antibody-dependent phagocytosis of lymphoma cells by macrophages

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    Antibody-dependent cellular phagocytosis (ADCP) by macrophages, an important effector function of tumor targeting antibodies, is hampered by ‘DonÂŽt Eat Me!’ signals such as CD47 expressed by cancer cells. Yet, human leukocyte antigen (HLA) class I expression may also impair ADCP by engaging leukocyte immunoglobulin-like receptor subfamily B (LILRB) member 1 (LILRB1) or LILRB2. Analysis of different lymphoma cell lines revealed that the ratio of CD20 to HLA class I cell surface molecules determined the sensitivity to ADCP by the combination of rituximab and an Fc-silent variant of the CD47 antibody magrolimab (CD47-IgGσ). To boost ADCP, Fc-silent antibodies against LILRB1 and LILRB2 were generated (LILRB1-IgGσ and LILRB2-IgGσ, respectively). While LILRB2-IgGσ was not effective, LILRB1-IgGσ significantly enhanced ADCP of lymphoma cell lines when combined with both rituximab and CD47-IgGσ. LILRB1-IgGσ promoted serial engulfment of lymphoma cells and potentiated ADCP by non-polarized M0 as well as polarized M1 and M2 macrophages, but required CD47 co-blockade and the presence of the CD20 antibody. Importantly, complementing rituximab and CD47-IgGσ, LILRB1-IgGσ increased ADCP of chronic lymphocytic leukemia (CLL) or lymphoma cells isolated from patients. Thus, dual checkpoint blockade of CD47 and LILRB1 may be promising to improve antibody therapy of CLL and lymphomas through enhancing ADCP by macrophages

    Proceedings of the 3rd Biennial Conference of the Society for Implementation Research Collaboration (SIRC) 2015: advancing efficient methodologies through community partnerships and team science

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    It is well documented that the majority of adults, children and families in need of evidence-based behavioral health interventionsi do not receive them [1, 2] and that few robust empirically supported methods for implementing evidence-based practices (EBPs) exist. The Society for Implementation Research Collaboration (SIRC) represents a burgeoning effort to advance the innovation and rigor of implementation research and is uniquely focused on bringing together researchers and stakeholders committed to evaluating the implementation of complex evidence-based behavioral health interventions. Through its diverse activities and membership, SIRC aims to foster the promise of implementation research to better serve the behavioral health needs of the population by identifying rigorous, relevant, and efficient strategies that successfully transfer scientific evidence to clinical knowledge for use in real world settings [3]. SIRC began as a National Institute of Mental Health (NIMH)-funded conference series in 2010 (previously titled the “Seattle Implementation Research Conference”; $150,000 USD for 3 conferences in 2011, 2013, and 2015) with the recognition that there were multiple researchers and stakeholdersi working in parallel on innovative implementation science projects in behavioral health, but that formal channels for communicating and collaborating with one another were relatively unavailable. There was a significant need for a forum within which implementation researchers and stakeholders could learn from one another, refine approaches to science and practice, and develop an implementation research agenda using common measures, methods, and research principles to improve both the frequency and quality with which behavioral health treatment implementation is evaluated. SIRC’s membership growth is a testament to this identified need with more than 1000 members from 2011 to the present.ii SIRC’s primary objectives are to: (1) foster communication and collaboration across diverse groups, including implementation researchers, intermediariesi, as well as community stakeholders (SIRC uses the term “EBP champions” for these groups) – and to do so across multiple career levels (e.g., students, early career faculty, established investigators); and (2) enhance and disseminate rigorous measures and methodologies for implementing EBPs and evaluating EBP implementation efforts. These objectives are well aligned with Glasgow and colleagues’ [4] five core tenets deemed critical for advancing implementation science: collaboration, efficiency and speed, rigor and relevance, improved capacity, and cumulative knowledge. SIRC advances these objectives and tenets through in-person conferences, which bring together multidisciplinary implementation researchers and those implementing evidence-based behavioral health interventions in the community to share their work and create professional connections and collaborations

    A Phase i Study of an MPS1 Inhibitor (BAY 1217389) in Combination with Paclitaxel Using a Novel Randomized Continual Reassessment Method for Dose Escalation

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    Purpose: Monopolar spindle 1 (MPS1) kinase inhibitor, BAY 1217389 (BAY) synergizes with paclitaxel. This phase I study assessed the combination of BAY with paclitaxel using a novel randomized continuous reassessment method (rCRM) to improve dose determination. Patients and Methods: Patients with solid tumors were randomized to receive oralBAY(twice daily 2-days-on/5-days-off) withweekly paclitaxel (90 mg/m2) or paclitaxel monotherapy in cycle 1. Dose escalation was guided by CRM modeling. Primary objectives were to assess safety, establish the MTD of BAY, and to evaluate the pharmacokinetic profiles for both compounds. Simulations were performed to determine the contribution of the rCRM for dose determination. Results: In total, 75 patients were enrolled. The main doselimiting toxicities were hematologic toxicities (55.6%). The MTD of BAY was established at 64 mg twice daily with paclitaxel. Inclusion of a control arm enabled the definitive attribution of grade ≄3 neutropenia to higher BAY exposure [AUC0-12 (P< 0.001)]. After determining the MTD, we included 19 patients with breast cancer at this dose for dose expansion. Other common toxicities were nausea (45.3%), fatigue (41.3%), and diarrhea (40.0%). Overall confirmed responses were seen in 31.6% of evaluable patients. Simulations showed that rCRM outperforms traditional designs in determining the true MTD. Conclusions: The combination of BAY with paclitaxel was associated with considerable toxicity without a therapeutic window. However, the use of the rCRM design enabled us to determine the exposure-toxicity relation for BAY. Therefore, we propose that the rCRM could improve dose determination in phase I trials that combine agents with overlapping toxicities. _2021 American Association for Cancer Research

    A prospective multicentre study of the epidemiology and outcomes of bloodstream infection in cirrhotic patients

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    ESGBIS/BICHROME Study Group: C. Campoli, G. Siccardi, S. Ambretti, A. Stallmach, M. Venditti, C. Lucidi, S. Ludovisi, M. De Cueto, M. D. Navarro, E. Lopez Cortes, E. Bouza, M. Valerio, A. Eworo, R. Losito, M. Senzolo, E. Nadal, A. Ottobrelli, M. Varguvic, C. Badia, G. Borgia, I. Gentile, A. R. Buonomo, E. Boumis, A. Beteta-Lopez, A. Rianda, G. Taliani, S. Grieco.[Objectives] To describe the current epidemiology of bloodstream infection (BSI) in patients with cirrhosis; and to analyse predictors of 30-day mortality and risk factors for antibiotic resistance.[Methods] Cirrhotic patients developing a BSI episode were prospectively included at 19 centres in five countries from September 2014 to December 2015. The discrimination of mortality risk scores for 30-day mortality were compared by area under the receiver operator risk and Cox regression models. Risk factors for multidrug-resistant organisms (MDRO) were assessed with a logistic regression model.[Results] We enrolled 312 patients. Gram-negative bacteria, Gram-positive bacteria and Candida spp. were the cause of BSI episodes in 53%, 47% and 7% of cases, respectively. The 30-day mortality rate was 25% and was best predicted by the Sequential Organ Failure Assessment (SOFA) and Chronic Liver Failure–SOFA (CLIF-SOFA) score. In a Cox regression model, delayed (>24 hours) antibiotic treatment (hazard ratio (HR) 7.58; 95% confidence interval (CI) 3.29–18.67; p < 0.001), inadequate empirical therapy (HR 3.14; 95% CI 1.93–5.12; p < 0.001) and CLIF-SOFA score (HR 1.35; 95% CI 1.28–1.43; p < 0.001) were independently associated with 30-day mortality. Independent risk factors for MDRO (31% of BSIs) were previous antimicrobial exposure (odds ratio (OR) 2.91; 95% CI 1.73–4.88; p < 0.001) and previous invasive procedures (OR 2.51; 95% CI 1.48–4.24; p 0.001), whereas spontaneous bacterial peritonitis as BSI source was associated with a lower odds of MDRO (OR 0.30; 95% CI 0.12–0.73; p 0.008).[Conclusions] MDRO account for nearly one-third of BSI in cirrhotic patients, often resulting in delayed or inadequate empirical antimicrobial therapy and increased mortality rates. Our data suggest that improved prevention and treatment strategies for MDRO are urgently needed in the liver cirrhosis patients

    Extended Infusion of beta-lactams for bloodstream infection in patients with liver cirrhosis: an observational multicenter study

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    For the ESGBIS/BICHROME study group.[Background] We analyzed the impact of continuous/extended infusion (C/EI) vs intermittent infusion of piperacillin-tazobactam (TZP) and carbapenems on 30-day mortality of patients with liver cirrhosis and bloodstream infection (BSI). [Methods] The BICRHOME study was a prospective, multicenter study that enrolled 312 cirrhotic patients with BSI. In this secondary analysis, we selected patients receiving TZP or carbapenems as adequate empirical treatment. The 30-day mortality of patients receiving C/EI or intermittent infusion of TZP or carbapenems was assessed with Kaplan-Meier curves, Cox-regression model, and estimation of the average treatment effect (ATE) using propensity score matching. [Results] Overall, 119 patients received TZP or carbapenems as empirical treatment. Patients who received C/EI had a significantly lower mortality rate (16% vs 36%, P = .047). In a Cox-regression model, the administration of C/EI was associated with a significantly lower mortality (hazard ratio [HR], 0.41; 95% confidence interval [CI], 0.11–0.936; P = .04) when adjusted for severity of illness and an ATE of 25.6% reduction in 30-day mortality risk (95% CI, 18.9–32.3; P < .0001) estimated with propensity score matching. A significant reduction in 30-day mortality was also observed in the subgroups of patients with sepsis (HR, 0.21; 95% CI, 0.06–0.74), acute-on-chronic liver failure (HR, 0.29; 95% CI, 0.03–0.99), and a model for end-stage liver disease score ≄25 (HR, 0.26; 95% CI, 0.08–0.92). At competing risk analysis, C/EI of beta-lactams was associated with significantly higher rates of hospital discharge (subdistribution hazard [95% CI], 1.62 [1.06–2.47]). [Conclusions] C/EI of beta-lactams in cirrhotic patients with BSI may improve outcomes and facilitate earlier discharge.J. R.-B. and P. R. receive funds for research from Plan Nacional de I+D+i 2013‐2016 and Instituto de Salud Carlos III, SubdirecciĂłn General de Redes y Centros de InvestigaciĂłn Cooperativa, Ministerio de EconomĂ­a, Industria y Competitividad, Spanish Network for Research in Infectious Diseases (REIPI RD16/0016/0001), cofinanced by European Development Regional Fund “A Way to Achieve Europe,” Operative Programme Intelligent Growth 2014–2020
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