16 research outputs found

    Dispersive liquid–liquid microextraction combined with laser-induced breakdown spectrometry and inductively coupled plasma optical emission spectrometry to elemental analysis

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    In this paper, two analytical methodologies based on the combination of dispersive liquid–liquid microextraction with inductively coupled plasma optical emission spectrometry and laser-induced breakdown spectrometry, respectively, were evaluated for simultaneous preconcentration and detection of Cd, Co, Ni, Pb and Zn. The microextraction procedure was based on the injection of appropriate quantities of 1-undecanol and methanol into the sample solution containing the complexes formed between metal ions and 1-(2-pyridylazo) 2-naphtol (PAN). The main experimental factors affecting the complexation and the extraction of metals (pH, PAN concentration, salt addition and extractant solvent and disperser solvent volume) were optimized using a multivariate analysis consisting of two steps: a Plackett-Burman design followed by a Circumscribed Central Composite Design (CCCD). Under optimum microextraction conditions, the analytical features of the proposed methodologies were assessed. Accuracy was evaluated by analyzing two certified reference materials, yielding results in agreement with the certified values. Both methodologies were applied to the analysis of a number of beverage samples.National Council for Scientific and Technological Development (Brazil) (CNPq – Science without Borders project no. 245782/2012-5). São Paulo Foundation Research (FAPESP project no. 2011/19730-3). This research has been supported by Government of Spain (CTQ2011-23968) and Regional Government of Valencia (Spain) (ACOMP/2013/072)

    Relation between Chlamydia trachomatis, the trophoblast and preterm delivery

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    There is a connection between preterm labor and intrauterie infections which is well established in up to 40% of cases. Success of the interaction between the invading trophoblast at the maternal-fetal interface and the maternal immune system is an immunologically unique fact. In this process the trophoblast participates in both the immune suppression which is necessary for tolerance to the semialogenic fetus and the immune activation against damaging factors such as infections. Alterations in this type of cross-talk, as in the cases of infection-triggered inflammation by Chlamydia species, could result in pregnancy complications such as prematurity or spontaneous abortion.Related articles and clinical cases have been gathered and reviewed to establish the main mechanisms and to confirm the relationship between preterm labor and Chlamydia trachomatis infection

    Vortex-assisted dispersive liquid–liquid microextraction for the determination of molybdenum in plants by inductively coupled plasma optical emission spectrometry

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    A new procedure for determining trace concentrations of Mo in plants combining dispersive liquid–liquid microextraction and inductively coupled plasma optical emission spectrometry is proposed here. An automated discrete sample introduction system using a Flow BlurringÂź multiple nebulizer (FBMN) and a solenoid valve were used to insert an organic rich phase into the plasma. The experimental conditions for the microextraction procedure were: 0.5% m v−1 of 8-hydroxyquinoline, pH 3.6 and 50 ÎŒL of 1-undecanol as the extractant. A limit of detection of the instrument of 0.20 ÎŒg L−1, a limit of detection of the procedure of 17 ÎŒg kg−1 and an enhancement factor of 246 were obtained employing the developed procedure. Three certified reference materials were used to check the accuracy and no significant differences were found at the 95% confidence level between certified and determined values. The developed procedure was also successfully applied to the determination of Mo in three different varieties of sugar cane leaves samples.The authors express their gratitude to the Coordenação de Aperfeiçoamento de Pessoal de NĂ­vel Superior CAPES (Grant CAPES-DGU 243/11) for the research fellowship provided to J.A.V.A.B. J.A.N. is thankful to Conselho Nacional de Desenvolvimento CientĂ­fico e TecnolĂłgico (CNPq, Brazil) for financial support. The authors are grateful to the Government of Spain (CTQ2011-23968 and PHB2010-0018-PC) and the Regional Government of Valencia (Spain) (ACOMP/2013/072) for the financial support, Agilent Technologies Inc. for the loan of the ICP-OES spectrometer and OneNebÂź (Division of Ingeniatrics TecnologĂ­as S.L.) for the FBMN prototype provided

    Elemental speciation by capillary electrophoresis with inductively coupled plasma spectrometry: A new approach by flow focusingÂź nebulization

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    A novel system for Capillary Electrophoresis (CE) and Inductively Coupled Plasma (ICP) sample introduction that incorporates a dedicated Flow-FocusingÂź based nebulizer as aerosol generation unit is presented, aiming to provide high signal sensitivity and low detection limits for element speciation at short analysis times. To prove its viability, the system prototype constructed has been coupled to an inductively coupled plasma - optical emission spectrometer (ICP-OES) and an inductively coupled plasma - mass spectrometer (ICP-MS) for Cr(III) and Cr(VI) speciation. Separation - nebulization system and operation parameters (i.e., capillary length, nebulizer geometry, carrier flow, carrier ionic strength, separation potential and sample injection volume) have been considered and studied, and the analytical figures of merit obtained for model samples in ICP-MS are presented. The results obtained show that the developed instrumental system permits Cr speciation in less than two minutes with detection limits of 0.1, 0.2 and 0.03 ÎŒg/L for Cr(III), Cr(VI) and total Cr, respectively.The authors are grateful to the Spanish Government (project CTQ2008-06730-C02-01), the Valencian Government (project ACOMP/2010/047), the NSF of Bulgaria (project DO 02-07 GAMMA) and the European Commission (EC FP7 24588 BioSupport project) for the financial support

    Analysis of metals and phosphorus in biodiesel B100 from different feedstock using a Flow BlurringÂź multinebulizer in inductively coupled plasma-optical emission spectrometry

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    A simple and fast method for determining the content of Na, K, Ca, Mg, P, and 20 heavy metals in biodiesel samples with inductively coupled plasma optical emission spectrometry (ICP OES) using a two-nozzle Flow BlurringÂź multinebulizer prototype and on-line internal standard calibration, are proposed. The biodiesel samples were produced from different feedstock such as sunflower, corn, soybean and grape seed oils, via a base catalyst transesterification. The analysis was carried out without any sample pretreatment. The standards and samples were introduced through one of the multinebulizer nozzles, while the aqueous solution containing yttrium as an internal standard was introduced through the second nozzle. Thus, the spectral interferences were compensated and the formation of carbon deposits on the ICP torch was prevented. The determination coefficients (R2) were greater than 0.99 for the studied analytes, in the range 0.21–14.75 mg kg−1. Short-term and long-term precisions were estimated as relative standard deviation. These were acceptable, their values being lower than 10%. The LOQ for major components such as Ca, K, Mg, Na, and P, were within a range between 4.9 ng g−1 for Mg (279.553 nm) and 531.1 ng g−1 for Na (588.995 nm), and for the other 20 minor components they were within a range between 1.1 ng g−1 for Ba (455.403 nm) and 2913.9 ng g−1 for Pb (220.353 nm). Recovery values ranged between 95% and 106%.The authors gratefully acknowledge Universidad Nacional del Sur (UNS) and Instituto de QuĂ­mica del Sur – Universidad Nacional del Sur – Consejo Nacional de Investigaciones CientĂ­ficas y TĂ©cnicas (INQUISUR-UNS-CONICET) from Argentina for the financial support. FDAO acknowledges Universidad de Alicante (UA) for his short visit fellowship. Ministerio de Asuntos Exteriores y de CooperaciĂłn (MAEC) and DirecciĂłn de Relaciones Culturales y CientĂ­ficas (AECID) from Spain for the financial support. The authors wish to thank the Spanish Government (CTQ2011-23968) for the financial support

    Goodbye Hartmann trial: a prospective, international, multicenter, observational study on the current use of a surgical procedure developed a century ago

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    Background: Literature suggests colonic resection and primary anastomosis (RPA) instead of Hartmann's procedure (HP) for the treatment of left-sided colonic emergencies. We aim to evaluate the surgical options globally used to treat patients with acute left-sided colonic emergencies and the factors that leading to the choice of treatment, comparing HP and RPA. Methods: This is a prospective, international, multicenter, observational study registered on ClinicalTrials.gov. A total 1215 patients with left-sided colonic emergencies who required surgery were included from 204 centers during the period of March 1, 2020, to May 31, 2020. with a 1-year follow-up. Results: 564 patients (43.1%) were females. The mean age was 65.9 ± 15.6 years. HP was performed in 697 (57.3%) patients and RPA in 384 (31.6%) cases. Complicated acute diverticulitis was the most common cause of left-sided colonic emergencies (40.2%), followed by colorectal malignancy (36.6%). Severe complications (Clavien-Dindo ≄ 3b) were higher in the HP group (P < 0.001). 30-day mortality was higher in HP patients (13.7%), especially in case of bowel perforation and diffused peritonitis. 1-year follow-up showed no differences on ostomy reversal rate between HP and RPA. (P = 0.127). A backward likelihood logistic regression model showed that RPA was preferred in younger patients, having low ASA score (≀ 3), in case of large bowel obstruction, absence of colonic ischemia, longer time from admission to surgery, operating early at the day working hours, by a surgeon who performed more than 50 colorectal resections. Conclusions: After 100 years since the first Hartmann's procedure, HP remains the most common treatment for left-sided colorectal emergencies. Treatment's choice depends on patient characteristics, the time of surgery and the experience of the surgeon. RPA should be considered as the gold standard for surgery, with HP being an exception

    Infected pancreatic necrosis: outcomes and clinical predictors of mortality. A post hoc analysis of the MANCTRA-1 international study

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    : The identification of high-risk patients in the early stages of infected pancreatic necrosis (IPN) is critical, because it could help the clinicians to adopt more effective management strategies. We conducted a post hoc analysis of the MANCTRA-1 international study to assess the association between clinical risk factors and mortality among adult patients with IPN. Univariable and multivariable logistic regression models were used to identify prognostic factors of mortality. We identified 247 consecutive patients with IPN hospitalised between January 2019 and December 2020. History of uncontrolled arterial hypertension (p = 0.032; 95% CI 1.135-15.882; aOR 4.245), qSOFA (p = 0.005; 95% CI 1.359-5.879; aOR 2.828), renal failure (p = 0.022; 95% CI 1.138-5.442; aOR 2.489), and haemodynamic failure (p = 0.018; 95% CI 1.184-5.978; aOR 2.661), were identified as independent predictors of mortality in IPN patients. Cholangitis (p = 0.003; 95% CI 1.598-9.930; aOR 3.983), abdominal compartment syndrome (p = 0.032; 95% CI 1.090-6.967; aOR 2.735), and gastrointestinal/intra-abdominal bleeding (p = 0.009; 95% CI 1.286-5.712; aOR 2.710) were independently associated with the risk of mortality. Upfront open surgical necrosectomy was strongly associated with the risk of mortality (p < 0.001; 95% CI 1.912-7.442; aOR 3.772), whereas endoscopic drainage of pancreatic necrosis (p = 0.018; 95% CI 0.138-0.834; aOR 0.339) and enteral nutrition (p = 0.003; 95% CI 0.143-0.716; aOR 0.320) were found as protective factors. Organ failure, acute cholangitis, and upfront open surgical necrosectomy were the most significant predictors of mortality. Our study confirmed that, even in a subgroup of particularly ill patients such as those with IPN, upfront open surgery should be avoided as much as possible. Study protocol registered in ClinicalTrials.Gov (I.D. Number NCT04747990)

    Speciation of chromium by dispersive liquid–liquid microextraction followed by laser-induced breakdown spectrometry detection (DLLME–LIBS)

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    In this study, an analytical methodology based on a combination of dispersive liquid–liquid microextraction with laser-induced breakdown spectrometry was evaluated for simultaneous pre-concentration, speciation and detection of Cr. The microextraction procedure was based on the injection of appropriated quantities of 1-undecanol and ethanol into a sample solution containing the complexes formed between Cr(VI) and diethyldithiocarbamate (DDTC). The main experimental factors affecting the complexation and the extraction of metal (pH, DDTC concentration, extractant and volume of disperser solvents) were optimized using a multivariate analysis consisting of two steps: a Plackett–Burman design followed by a Circumscribed Central Composite Design (CCCD). Under optimum microextraction conditions, the analytical figures of merit of the proposed methodology were assessed. The method was finally applied to the analysis of a certified reference material hard drinking water (ERM¼ CA011a), yielding results in good agreement with the certified value.National Council for Scientific and Technological Development (Brazil) (CNPq - Science without Borders project no. 245782/2012-5) and São Paulo Foundation Research (FAPESP project no. 2011/19730-3) are acknowledged. This study has been supported by the Government of Spain (CTQ2011-23968) and the Regional Government of Valencia (Spain) (ACOMP/2013/072)
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