749 research outputs found

    Complexation forces in aqueous solution. Calorimetric studies of the association of 2-hydroxypropyl-b-cyclodextrin with monocarboxylic acids or cycloalkanols.

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    The formation of complexes between 2-hydroxypropyl-b-cyclodextrin and monocarboxylic acids or cycloalkanols has been studied calorimetrically at 298 K in phosphate buffer, pH 11.3. The forces involved in the assocn. process are discussed in the light of the signs and values of the thermodn. parameters obtained: assocn. enthalpy, binding const., Gibbs free energy, and entropy. For monocarboxylic acids, hydrophobic interactions are the primary force detg. complexation, as indicated by the small enthalpies and by the high and pos. entropies. For the cycloalkanols, instead, enthalpies are neg. and entropies pos. or neg., depending on the solvent medium employed, namely water or phosphate buffer. The most important requirement for the formation of the complex is a good spatial fit between the two interacting mols. A cavity elongation effect occurs because of the presence of the hydroxypropyl groups on the rim of the macrocycle. The relative contribution of hydrophobic and van der Waals interactions varies with the dimensions of the guest mols. A linear correlation exists between enthalpy and entropy of complexation, underlying that inclusion is a process dominated by hydration phenomena and ascribed to the modifications experienced by the solvent in the hydration shells of the interacting substances

    Non-diagonal open spin-1/2 XXZ quantum chains by separation of variables: Complete spectrum and matrix elements of some quasi-local operators

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    The integrable quantum models, associated to the transfer matrices of the 6-vertex reflection algebra for spin 1/2 representations, are studied in this paper. In the framework of Sklyanin's quantum separation of variables (SOV), we provide the complete characterization of the eigenvalues and eigenstates of the transfer matrix and the proof of the simplicity of the transfer matrix spectrum. Moreover, we use these integrable quantum models as further key examples for which to develop a method in the SOV framework to compute matrix elements of local operators. This method has been introduced first in [1] and then used also in [2], it is based on the resolution of the quantum inverse problem (i.e. the reconstruction of all local operators in terms of the quantum separate variables) plus the computation of the action of separate covectors on separate vectors. In particular, for these integrable quantum models, which in the homogeneous limit reproduce the open spin-1/2 XXZ quantum chains with non-diagonal boundary conditions, we have obtained the SOV-reconstructions for a class of quasi-local operators and determinant formulae for the covector-vector actions. As consequence of these findings we provide one determinant formulae for the matrix elements of this class of reconstructed quasi-local operators on transfer matrix eigenstates.Comment: 40 pages. Minor modifications in the text and some notations and some more reference adde

    Duration of remission after halving of the etanercept dose in patients with ankylosing spondylitis: a randomized, prospective, long-term, follow-up study

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    Fabrizio Cantini, Laura Niccoli, Emanuele Cassarà, Olga Kaloudi, Carlotta NanniniDivision of Rheumatology, Misericordia e Dolce Hospital, Prato, ItalyBackground: The aim of this study was to evaluate the proportion of patients with ankylosing spondylitis maintaining clinical remission after reduction of their subcutaneous etanercept dose to 50 mg every other week compared with that in patients receiving etanercept 50 mg weekly.Methods: In the first phase of this randomized, prospective, follow-up study, all biologic-naïve patients identified between January 2005 and December 2009 as satisfying the modified New York clinical criteria for ankylosing spondylitis treated with etanercept 50 mg weekly were evaluated for disease remission in January 2010. In the second phase, patients meeting the criteria for remission were randomized to receive subcutaneous etanercept as either 50 mg weekly or 50 mg every other week. The randomization allocation was 1:1. Remission was defined as Bath Ankylosing Spondylitis Disease Activity Index < 4, no extra-axial manifestations of peripheral arthritis, dactylitis, tenosynovitis, or iridocyclitis, and normal acute-phase reactants. The patients were assessed at baseline, at weeks 4 and 12, and every 12 weeks thereafter. The last visit constituted the end of the follow-up.Results: During the first phase, 78 patients with ankylosing spondylitis (57 males and 21 females, median age 38 years, median disease duration 12 years) were recruited. In January 2010, after a mean follow-up of 25 ± 11 months, 43 (55.1%) patients achieving clinical remission were randomized to one of the two treatment arms. Twenty-two patients received etanercept 50 mg every other week (group 1) and 21 received etanercept 50 mg weekly (group 2). At the end of follow-up, 19 of 22 (86.3%) subjects in group 1 and 19 of 21 (90.4%) in group 2 were still in remission, with no significant difference between the two groups. The mean follow-up duration in group 1 and group 2 was 22 ± 1 months and 21 ± 1.6 months, respectively.Conclusion: Remission of ankylosing spondylitis is possible in at least 50% of patients treated with etanercept 50 mg weekly. After halving of the etanercept dose, remission is maintained in a high percentage of patients during long-term follow-up, with important economic implications.Keywords: ankylosing spondylitis, anti-tumor necrosis factor, etanercept, remission, dose reductio

    The Effect of Cromolyn Sodium and Nedocromil Sodium Administered by A pressurized Aerosol with A spacer Device on Exercise-Induced Asthma in Children

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    To compare the effectiveness of cromolyn sodium (CS) (10 mg) and nedocromil sodium (NS) (4 mg) administered by a metered dose inhaler (MDI) with a spacer device in preventing exercise-induced asthma (EIA), eight asthmatic children with EIA were studied in a randomized double-blind, cross-over, placebo-controlled study, CS and NS provided significant, comparable protection from EIA and both were better than placebo. We conclude that CS and NS administered by a pressurized aerosol with a spacer device provide equal protection against EIA in children

    Potential pesticide transport in Colorado agriculture: a model comparison

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    .30 September 1989.Includes bibliographical references (pages [50]-52)Grant no. 14-08-0001-1551, Project no. 09; financed in part by the U.S. Department of the Interior, Geological Survey, through the Colorado Water Resources Research Institute

    The role of 18F-FDG PET/CT in endometrial adenocarcinoma: a review of the literature and recent advances

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    Purpose: To provide a substantial coverage on the role of 18F-FDG PET/CT in endometrial cancer (EC), and identify the key issues which make its use recommended with both low level of evidence and low strength of recommendation in accordance with the last consensus conference. Methods: A comprehensive literature computer search was performed on PubMed/MEDLINE and Cochrane Library databases up to June 2020. Included studies had to focus on 18F-FDG PET/CT in EC, with regard to staging, follow-up and prognostic value. Review guidelines, systematic review, meta-analyses and original papers were included. Results: The 18F-FDG PET/CT is affected by suboptimal soft tissue differentiation, with sensitivity and specificity in tumor staging ranged from 77 to 85% and 79 to 96%. The sensitivity and the specificity of 18F-FDG PET/CT performed at staging for lymph node metastases ranged from 63 to 73% and 96 to 97%. For distant metastases, sensitivity and specificity of 18F-FDG PET/CT performed at staging ranged from 63 to 80% and 93 to 96%. After treatment, better performance emerged for EC recurrent with sensitivity ranged from 92 to 98% and specificity ranged from 89 to 94%. Maximum standardized uptake value (SUVmax) and metabolic volumetric parameters, such as total lesion glycolysis (TLG) and metabolic tumor volume (MTV), resulted to be significantly related to prognosis. Conclusion: Despite evidence-based data about the diagnostic performance are increasing, the low sensitivity represents the main limitation of 18F-FDG PET/CT imaging utilization for the detection of primary tumor and lymph node metastases. Better performances were observed for distant metastasis and EC recurrence. Further randomized prospective studies are needed to increase both the low level of evidence and low strength of recommendation for using 18F-FDG PET/CT in EC. Promising results emerged from PET/MRI

    Antiperiodic dynamical 6-vertex model I: Complete spectrum by SOV, matrix elements of the identity on separate states and connections to the periodic 8-vertex model

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    The spin-1/2 highest weight representations of the dynamical 6-vertex and the standard 8-vertex Yang-Baxter algebra on a finite chain are considered in this paper. For the antiperiodic dynamical 6-vertex transfer matrix defined on chains with an odd number of sites, we adapt the Sklyanin's quantum separation of variable (SOV) method and explicitly construct SOV representations from the original space of representations. We provide the complete characterization of eigenvalues and eigenstates proving also the simplicity of its spectrum. Moreover, we characterize the matrix elements of the identity on separated states by determinant formulae. The matrices entering in these determinants have elements given by sums over the SOV spectrum of the product of the coefficients of separate states. This SOV analysis is not reduced to the case of the elliptic roots of unit and the results here derived define the required setup to extend to the dynamical 6-vertex model the approach recently developed in [1]-[5] to compute the form factors of the local operators in the SOV framework, these results will be presented in a future publication. For the periodic 8-vertex transfer matrix, we prove that its eigenvalues have to satisfy a fixed system of equations. In the case of a chain with an odd number of sites, this system of equations is the same entering in the SOV characterization of the antiperiodic dynamical 6-vertex transfer matrix spectrum. This implies that the set of the periodic 8-vertex eigenvalues is contained in the set of the antiperiodic dynamical 6-vertex eigenvalues. A criterion is introduced to find simultaneous eigenvalues of these two transfer matrices and associate to any of such eigenvalues one nonzero eigenstate of the periodic 8-vertex transfer matrix by using the SOV results. Moreover, a preliminary discussion on the degeneracy of the periodic 8-vertex spectrum is also presented.Comment: 36 pages, main modifications in section 3 and one appendix added, no result modified for the dynamical 6-vertex transfer matrix spectrum and the matrix elements of identity on separate states for chains with an odd number of site

    Response to erlotinib in a patient with lung adenocarcinoma harbouring the EML4-ALK translocation: A case report.

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    Lung cancer is the leading cause of cancer-associated mortality worldwide, and the mainstay of treatment remains to be personalised therapy. Tyrosine kinase inhibitors of the epidermal growth factor receptor (EGFR-TKIs) have been reported to exert a significant impact in the treatment of non-small cell lung cancer (NSCLC), particularly in patients harbouring mutations in the EGFR gene. The echinoderm microtubule-associated protein-like 4-anaplastic lymphoma kinase (EML4-ALK) gene translocation has been described in a subset of patients with NSCLC and possesses potent oncogenic activity. This translocation represents one of the most novel molecular targets in the treatment of NSCLC. Patients who harbour the EML4-ALK rearrangement possess lung tumours that lack EGFR or K-ras mutations. The present study reports the case of a patient possessing the EML4-ALK rearrangement that was initially treated with erlotinib and achieved a lasting clinical response. To the best of our knowledge, the current study is the first report of a clinical response to EGFR-TKI in a patient with lung adenocarcinoma harbouring the EML4-ALK fusion gene, but no EGFR mutations. However, as the disease progressed, the ALK gene status of the tumour was investigated, and based upon a positive result, the patient was treated with crizotinib and achieved a complete response. In conclusion, the present study suggests that the EML4-ALK rearrangement is not always associated with resistance to EGFR-TKIs. Further studies are required to clarify the biological features of these tumours and to investigate the mechanisms underlying the primary resistance to EGFR-TKIs when the EML4-ALK rearrangement is present

    C9orf72 repeat expansions cause neurodegeneration in Drosophila through arginine-rich proteins

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    An expanded GGGGCC repeat in C9orf72 is the most common genetic cause of frontotemporal dementia and amyotrophic lateral sclerosis. A fundamental question is whether toxicity is driven by the repeat RNA itself and/or by dipeptide repeat proteins generated by repeat-associated, non-ATG translation. To address this question we developed in vitro and in vivo models to dissect repeat RNA and dipeptide repeat protein toxicity. Expression of pure repeats in Drosophila caused adult-onset neurodegeneration attributable to poly-(glycine-arginine) proteins. Thus, expanded repeats promoted neurodegeneration through neurotoxic proteins. Expression of individual dipeptide repeat proteins with a non-GGGGCC RNA sequence showed both poly-(glycine-arginine) and poly-(proline-arginine) proteins caused neurodegeneration. These findings are consistent with a dual toxicity mechanism, whereby both arginine-rich proteins and repeat RNA contribute to C9orf72-mediated neurodegeneration

    Procedural Impact of a Kissing-Balloon Predilation (Pre-Kissing) Technique in Patients With Complex Bifurcations Undergoing Drug-Eluting Stenting

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    Aim: To assess the impact of lesion predilation with kissing inflation using under-sized balloons (pre-kissing [PK]) on the procedural outcome of percutaneous intervention (PCI) on coronary bifurcation lesions (CBLs). Methods: Patients who underwent PCI with second-generation drug-eluting stenting on a complex CBL (Medina 1,1,1 or 1,0,1 or 0,1,1) were selected. The study population was divided according to the lesion preparation into the PK group and the control group. To adjust for higher anatomic complexity of PK patients, a 2:1 propensity-matched (PM)-control group was selected. The PCI procedural details were assessed to evaluate occurrence of "side-branch trouble" (primary procedural endpoint) after main-vessel (MV) stenting. Angiographic characteristics, including side-branch TIMI flow during PCI, were also systematically evaluated. Results: A total of 538 patients were identified, with 66 patients in the PK group, 472 patients in the control group, and 126 patients in the PM-control group. Side-branch trouble was less common in side-branch PK patients vs the PM-control patients (7.5% vs 18.0%, respectively; P=.03). In multivariable analysis, the absence of PK independently predicted side-branch trouble. Among selected patients with a long side-branch lesion (122 patients), the PK technique improved post-MV stenting side-branch TIMI flow. Conclusions: Use of PK with under-sized balloons may facilitate side-branch management after MV stenting in patients with complex CBL undergoing provisional stenting
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