714 research outputs found

    Synthesis of type A zeolites from natural kaolinite for their application in CO2 capture processes

    Get PDF
    Climate change is the greatest environmental threat of the 21st century, with major economic, social and environmental consequences. The level of carbon dioxide (CO2) emissions has increased by 31%, therefore, both governments and the scientific community are taking steps to mitigate emissions into the atmosphere. The most economically sustainable method is the use of low cost adsorbents that perform a selective adsorption of CO2 with respect to other inert gases such as N2. Clay minerals are highly available materials on the planet, are a low cost raw material and have great versatility for various processes in the field of adsorption and catalysis. The present work describes the synthesis of type A zeolite from a hydrothermal process in basic medium using metacaolinite as a starting material. Several parameters such as temperature and time were modified to evaluate the relationship between the formation conditions of the zeolite and its CO2 adsorption capacity. Synthesized catalysts were characterized by X-ray diffraction (XRD), N2 adsorption-desorption at -196 ºC, nuclear magnetic resonance of solids (NMR) and infrared spectroscopy (IR). In addition, the absorption capacity of CO2 with type A zeolites has been evaluated, and all the results were compared with the commercial zeolites. With respect to the results obtained, it can be said that the bands obtained by IR for the synthesized Zeolites are similar to those of the commercial Zeolite. On the other hand, the NMR results show that the synthesized and commercial zeolite present the same chemical environment. Finally, the textural parameters corroborate that in all cases the surface area is low from 12 m2g-1 for kaolinite to 7 m2g-1 for commercial zeolite AUniversidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

    Omeprazole Impairs Vascular Redox Biology And Causes Xanthine Oxidoreductase-mediated Endothelial Dysfunction

    Get PDF
    Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Proton pump inhibitors (PPIs) are widely used drugs that may increase the cardiovascular risk by mechanisms not entirely known. While PPIs increase asymmetric dimethylarginine (ADMA) levels and inhibit nitric oxide production, it is unknown whether impaired vascular redox biology resulting of increased xanthine oxidoreductase (XOR) activity mediates PPIs-induced endothelial dysfunction (ED). We examined whether increased XOR activity impairs vascular redox biology and causes ED in rats treated with omeprazole. We also examined whether omeprazole aggravates the ED found in hypertension. Treatment with omeprazole reduced endothelium-dependent aortic responses to acetylcholine without causing hypertension. However, omeprazole did not aggravate two-kidney, one-clip (2KIC) hypertension, nor hypertension-induced ED. Omeprazole and 2K1C increased vascular oxidative stress as assessed with dihydroethidium (DHE), which reacts with superoxide, and by the lucigenin chemiluminescence assay. The selective XOR inhibitor febuxostat blunted both effects induced by omeprazole. Treatment with omeprazole increased plasma ADMA concentrations, XOR activity and systemic markers of oxidative stress. Incubation of aortic rings with ADMA increased XOR activity, DHE fluorescence and lucigenin chemiluminescence signals, and febuxostat blunted these effects. Providing functional evidence that omeprazole causes ED by XOR-mediated mechanisms, we found that febuxostat blunted the ED caused by omeprazole treatment. This study shows that treatment with omeprazole impairs the vascular redox biology by XOR-mediated mechanisms leading to ED. While omeprazole did not further impair hypertension-induced ED, further studies in less severe animal models are warranted. Our findings may have major relevance, particularly to patients with cardiovascular diseases taking PPIs. (C) 2016 The Authors. Published by Elsevier B.V.9134143Fundacao de Amparo a Pesquisa do Estado de Sao Paulo (FAPESP) [2014-23946-0]Conselho Nacional de Desenvolvimento Cientifico e Tecnologico (CNPq)CAPES (Coordenadoria de Aperfeicoamento de Pessoal de Nivel Superior)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES

    Microfluidic flow injection immunoassay system for algal toxins determination: a case of study

    Get PDF
    A novel flow injection microfluidic immunoassay system for continuous monitoring of saxitoxin, a lethal biotoxin, in seawater samples is presented in this article. The system consists of a preimmobilized G protein immunoaffinity column connected in line with a lab-on-chip setup. The detection of saxitoxin in seawater was carried out in two steps: an offline incubation step (competition reaction) performed between the analyte of interest (saxitoxin or Ag, as standard or seawater sample) and a tracer (an enzyme-conjugated antigen or Ag*) toward a specific polyclonal antibody. Then, the mixture was injected through a "loop" of a few mu L using a six-way injection valve into a bioreactor, in line with the valve. The bioreactor consisted of a small glass column, manually filled with resin upon which G protein has been immobilized. When the mixture flowed through the bioreactor, all the antibody-antigen complex, formed during the competition step, is retained by the G protein. The tracer molecules that do not interact with the capture antibody and protein G are eluted out of the column, collected, and mixed with an enzymatic substrate directly within the microfluidic chip, via the use of two peristaltic pumps. When Ag* was present, a color change (absorbance variation, Delta Abs) of the solution is detected at a fixed wavelength (655 nm) by an optical chip docking system and registered by a computer. The amount of saxitoxin, present in the sample (or standard), that generates the variation of the intensity of the color, will be directly proportional to the concentration of the analyte in the analyzed solution. Indeed, the absorbance response increased proportionally to the enzymatic product and to the concentration of saxitoxin in the range of 3.5 x 10(-7)-2 x 10(-5) ng ml(-1) with a detection limit of 1 x 10(-7) ng ml(-1) (RSD% 15, S N-1 equal to 3). The immunoanalytical system has been characterized, optimized, and tested with seawater samples. This analytical approach, combined with the transportable and small-sized instrumentation, allows for easy in situ monitoring of marine water contaminations

    Safety, efficacy, and patient acceptability of single-dose fosaprepitant regimen for the prevention of chemotherapy-induced nausea and vomiting

    Get PDF
    Control of chemotherapy-induced nausea and vomiting (CINV) is a crucial factor in ensuring that patients undergoing cancer chemotherapy can get the full benefit of therapy. Current antiemetic guidelines recommend that the neurokinin-1 receptor (NK-1R) antagonist aprepitant should be used as part of a combination regimen with dexamethasone and a serotonin receptor antagonist for the prevention of CINV in patients receiving highly emetogenic chemotherapy (HEC). Fosaprepitant is a water-soluble N-phosphoryl derivative of aprepitant that, when infused, is rapidly metabolized back to an active aprepitant. The existing literature in PubMed about fosaprepitant was screened and selected in order to address the emerging data from two randomized clinical trials evaluating the efficacy and safety of a single-dose fosaprepitant regimen. These phase III trials demonstrated that fosaprepitant given as a single intravenous dose of 150 mg was either noninferior to the conventional 3-day aprepitant or significantly superior to placebo for the prevention of acute and delayed CINV in patients receiving high-dose cisplatin. In both trials, fosaprepitant was well tolerated although more frequent infusion-site adverse events were observed with fosaprepitant. The new dosage regimen of fosaprepitant, therefore, would be an option for CINV control in patients receiving cisplatin-based chemotherapy. The clinical efficacy is consistent with the findings from a time-on-target, positron-emission tomography study evaluating the NK-1R occupancy in the central nervous system (CNS) over 5 days after a single-dose infusion of 150 mg fosaprepitant in healthy participants. The single-dose regimen is capable of blocking more than 90% of the NK-1Rs in the CNS for at least 48 hours after infusion, which is sufficient to control delayed CINV for 2 to 5 days after HEC. The new dosage regimen of fosaprepitant can provide a simplified treatment option that maintains high protection while ensuring adherence to scheduled antiemetic medication throughout most of the 5-day period encompassing the major risk for CINV

    Understanding reasons and factors for participation and non-participation to a medication adherence program for patients with diabetic kidney disease in Switzerland: a mixed methods study.

    Get PDF
    An interprofessional medication adherence intervention led by pharmacists, combining motivational interviews and feedback with electronic monitor (EM) drug assessment, was offered to all consecutive patients with diabetic kidney disease (DKD) (estimated glomerular filtration rate < 60 mL/min/1.73 m <sup>2</sup> ) visiting their nephrologist or endocrinologist. Approximately 73% (202/275) of eligible patients declined to participate, and the factors and reasons for refusal were investigated. Sociodemographic and clinical data of included patients and those who refused were collected retrospectively for those who had previously signed the general consent form. Multivariate logistic regression analysis was performed to identify independent variables associated with non-participation. Patients who refused or accepted the adherence study were invited to participate in semi-structured interviews. Verbatim transcription, thematic analysis, and inductive coding were performed. Patients who refused to participate were older (n = 123, mean age 67.7 years, SD:10.4) than those who accepted (n = 57, mean age 64.0 years, SD:10.0, p = 0.027) and the proportion of women was higher among them than among patients who accepted it (30.9% vs 12.3%, p = 0.007). The time from diabetes diagnosis was longer in patients who refused than in those who accepted (median 14.2 years IQR 6.9-22.7 vs. 8.6 years, IQR 4.5-15.9, p = 0.003). Factors associated with an increased risk of non-participation were female sex (OR 3.8, 95% CI 1.4-10.0, p = 0.007) and the time from diabetes diagnosis (OR 1.05, 95% CI 1.01-1.09, p = 0.019). The included patients who were interviewed (n = 14) found the interprofessional intervention useful to improve their medication management, support medication literacy, and motivation. Patients who refused to participate and who were interviewed (n = 16) explained no perceived need, did not agree to use EM, and perceived the study as a burden and shared that the study would have been beneficial if introduced earlier in their therapeutic journey. Other barriers emerged as difficult relationships with healthcare providers, lack of awareness of the pharmacist's role, and negative perception of clinical research. Investigating the factors and reasons for participation and non-participation in a study helps tailor intervention designs to the needs of polypharmacy patients. Patients who refused the adherence intervention may not be aware of the benefits of medication management and medication literacy. There is an urgent need to advocate for interprofessional outpatient collaborations to support medication adherence in patients with DKD. Trial registration Clinicaltrials.gov NCT04190251_PANDIA IRIS

    Measurement of the tensor Ayy and vector Ay analyzing powers of the deuteron inelastic scattering off berillium at 5.0 GeV/c and 178 mr

    Full text link
    Tensor Ayy and vector Ay analyzing powers in the inelastic scattering of deuterons with the momentum of 5.0 GeV/c on beryllium at an angle of 178 mr in the vicinity of the excitation of baryonic resonances with masses up to 1.8 GeV/c^2 have been measured. The Ayy data are in a good agreement with the previous data obtained at 4.5 and 5.5 GeV/c. The results of the experiment are compared with the predictions of the plane wave impulse approximation and \omega-meson exchange models.Comment: 18 pages, 9 figure

    Should clinicians always administer dexamethasone beyond 24 h after chemotherapy to control delayed nausea and vomiting caused by moderately emetogenic regimens? : insight from the re-evaluation of two randomized studies

    Get PDF
    Purpose Data from two noninferiority trials of a dexamethasone-sparing regimen were assessed for the impact of acute nausea and vomiting on delayed outcome in patients undergoing moderately emetogenic chemotherapy (MEC) or anthracycline plus cyclophosphamide (AC). Methods Chemo-naive patients were randomized to receive palonosetron (0.25 mg IV) plus dexamethasone (8 mg IV) on day 1 of chemotherapy, or the same regimen followed by oral dexamethasone on days 2 and 3 in the MEC (n = 237) and AC (n = 380) cohorts. Patients were divided into two groups according to whether or not they experienced vomiting and/or moderate-to-severe nausea during the acute phase (high- and low-risk groups, respectively). Primary efficacy endpoint was the complete protection (CP) against delayed vomiting and moderate-to-severe nausea. Patient's satisfaction (0-100 mm visual analog scale) was also analyzed. Results Among the 209 low-risk patients undergoing MEC, delayed CP occurred in 82.9 % of those who received single-dose dexamethasone and 89.8 % of those who received 3-day dexamethasone (P = 0.165). Of the 271 low-risk patients undergoing AC, CP was achieved in 71.7 % of those treated with single-dose dexamethasone and 84.2 % treated with 3-day dexamethasone (P = 0.019). In spite of these observations, the patient satisfaction data was not influenced by dexamethasone regimen. In both cohorts, occurrence of acute vomiting or moderate-to-severe nausea was the key independent-predictor for delayed vomiting or nausea, respectively. Conclusions The dexamethasone-sparing regimen provides adequate delayed protection in patients undergoing MEC who are at low risk for delayed symptoms, and can still be discussed for low-risk AC patients as the daily difference in control is modest. Additional dexamethasone doses can be customized on the basis of occurrence or absence of acute symptoms in the first cycle of MEC and even AC
    corecore