Liver stiffness change with HCV cure in HIV-infected patients on non-nucleoside analogues.

BACKGROUND: Liver stiffness (LS) at sustained viral response (SVR) is strongly associated with a lower incidence of subsequent hepatic events. HIV NNRTIs may have a beneficial impact on fibrogenesis. OBJECTIVES: Our aim was to analyse the influence of NNRTI-based therapy on the change in LS from starting direct-acting antiviral (DAA) therapy to achieving SVR in HIV/HCV-coinfected patients. METHODS: Three hundred and thirteen HIV/HCV-coinfected patients who fulfilled the following criteria were included: (i) had achieved SVR with an IFN-free, DAA-including regimen; (ii) LS ≥9.5 kPa before therapy; (iii) LS measurement available at SVR; (iv) seronegative for HBsAg; and (v) ART containing 2 NRTIs plus either 1 NNRTI or 1 integrase inhibitor (INI) or 1-2 NRTIs plus 1 PI. LS changes were assessed. RESULTS: Seventy-four patients received NNRTI-based combinations [53 (71.6%) rilpivirine and 16 (21.6%) efavirenz] and 239 patients received other regimens. At baseline, the median (IQR) LS was 16.7 kPa (11.8-25.6) in the NNRTI group and 17.3 kPa (11.9-27.4) in the non-NNRTI group (P = 0.278). The median (IQR) percentage of LS decrease from baseline to SVR was 35.2% (18.2%-52.3%) for NNRTI-based therapy and 29.5% (10%-45.9%) for PI- or INI-based therapy (P = 0.018). In multivariate analysis, adjusted for sex, age, HCV genotype, NRTI backbone and propensity score for HIV therapy, NNRTI-based regimen use was associated with a higher LS decrease [ß = 11.088 (95% CI = 1.67-20.51); P = 0.021]. CONCLUSIONS: Treatment with NNRTI plus 2 NRTI combinations is associated with a higher LS decline than other ART combinations in HIV/HCV-coinfected patients receiving DAA-based therapy.

Graphene and carbon nanotubes as solid phase extraction sorbents for the speciation of chromium: A review.

In the last decades, the extensive use of chromium in industrial activities has led to the discharge of different chromium species into the biosphere. The two stable chromium forms are Cr(III) and Cr(VI), which have dramatically different properties. While the first one is essential, the second is harmful and carcinogenic, even at very low concentration. Therefore, the appropriate analysis of chromium in environmental, biological, food and other kind of samples need a reliable separation and subsequent quantification of both Cr species. The present paper provides a critical review of chromium speciation methods in which solid phase extraction was employed as sample pretreatment using graphene and carbon nanotubes (and their diverse oxidized, functionalized and magnetic derivatives) as sorbents. The different published methods for the speciation of Cr(III), Cr(VI) or both species are described and classified on the basis of the separation strategy employed: (i) the selective retention of only one of the two species by the sorbent, (ii) the retention of a Cr-chelate formed by using a ligand selective for only one of the Cr-species, or (iii) the sorption of both Cr(III) and Cr(VI) species. In addition, the distinct applied SPE modes (on-column, dispersive or magnetic) and their automation possibilities, the analytical techniques utilized for measurement of the Cr-species after separation, as well as the analytical figures of merit of the methods developed up to date are evaluated. Finally, the expected future trends of solid phase extraction for Cr speciation based on carbon nanomaterials such as graphene, carbon nanotubes and their derivatives as sorbents are commented.

Structural and microstructural characterization and properties of new phases in the Nd-Sr-Co-(Fe/Mn)-O system as air-electrodes in SOFCs.

New oxides of the (NdSr)n+1MO3n+1 (M = Co and Mn or Fe) series are reported. Compounds of composition NdSrCo0.75Fe0.25O4.10, NdSrCo0.75Mn0.25O4.08 and Nd0.5Sr1.5Co0.75Mn0.25O3.86 are the n = 1 members of the Ruddlesden-Popper homologous series (K2NiF4 structural type) as determined by X-ray diffraction and different transmission electron microscopy techniques. Their crystal structure consists of connected (Co-Fe/Mn)O6 octahedra blocks separated by (Nd/Sr)O rock-salt like layers along the c-axis. Interstitial oxygen atoms or anion vacancies are induced depending on composition. Oxides with interstitial oxygen show good performances as intermediate temperature solid oxide fuel cell (IT-SOFC) cathode. The area-specific resistance values of electrodes made of these oxides at 973 K in air are 0.18 Ω cm2 for NdSrCo0.75Fe0.25O4.10 and NdSrCo0.75Mn0.25O4.08 (comparable to the one of the state-of-the-art materials proposed as cathodes in IT-SOFC), and 1.38 Ω cm2 for Nd0.5Sr1.5Co0.75Mn0.25O3.86.

Magnetic solid-phase extraction using carbon nanotubes as sorbents: a review.

Magnetic solid-phase extraction (M-SPE) is a procedure based on the use of magnetic sorbents for the separation and preconcentration of different organic and inorganic analytes from large sample volumes. The magnetic sorbent is added to the sample solution and the target analyte is adsorbed onto the surface of the magnetic sorbent particles (M-SPs). Analyte-M-SPs are separated from the sample solution by applying an external magnetic field and, after elution with the appropriate solvent, the recovered analyte is analyzed. This approach has several advantages over traditional solid phase extraction as it avoids time-consuming and tedious on-column SPE procedures and it provides a rapid and simple analyte separation that avoids the need for centrifugation or filtration steps. As a consequence, in the past few years a great deal of research has been focused on M-SPE, including the development of new sorbents and novel automation strategies. In recent years, the use of magnetic carbon nanotubes (M-CNTs) as a sorption substrate in M-SPE has become an active area of research. These materials have exceptional mechanical, electrical, optical and magnetic properties and they also have an extremely large surface area and varied possibilities for functionalization. This review covers the synthesis of M-CNTs and the different approaches for the use of these compounds in M-SPE. The performance, general characteristics and applications of M-SPE based on magnetic carbon nanotubes for organic and inorganic analysis have been evaluated on the basis of more than 110 references. Finally, some important challenges with respect the use of magnetic carbon nanotubes in M-SPE are discussed.

Characterization of carbon nanotubes and analytical methods for their determination in environmental and biological samples: a review.

In the present paper, a critical overview of the most commonly used techniques for the characterization and the determination of carbon nanotubes (CNTs) is given on the basis of 170 references (2000-2014). The analytical techniques used for CNT characterization (including microscopic and diffraction, spectroscopic, thermal and separation techniques) are classified, described, and illustrated with applied examples. Furthermore, the performance of sampling procedures as well as the available methods for the determination of CNTs in real biological and environmental samples are reviewed and discussed according to their analytical characteristics. In addition, future trends and perspectives in this field of work are critically presented.

Solid phase extraction for the speciation and preconcentration of inorganic selenium in water samples: a review.

Selenium is an essential element for the normal cellular function of living organisms. However, selenium is toxic at concentrations of only three to five times higher than the essential concentration. The inorganic forms (mainly selenite and selenate) present in environmental water generally exhibit higher toxicity (up to 40 times) than organic forms. Therefore, the determination of low levels of different inorganic selenium species in water is an analytical challenge. Solid-phase extraction has been used as a separation and/or preconcentration technique prior to the determination of selenium species due to the need for accurate measurements for Se species in water at extremely low levels. The present paper provides a critical review of the published methods for inorganic selenium speciation in water samples using solid phase extraction as a preconcentration procedure. On the basis of more than 75 references, the different speciation strategies used for this task have been highlighted and classified. The solid-phase extraction sorbents and the performance and analytical characteristics of the developed methods for Se speciation are also discussed.

A fast chemometric procedure based on NIR data for authentication of honey with protected geographical indication.

In this work, information contained in near infrared (NIR) spectra of honeys with protected geographical indication (PGI) "Mel de Galicia" was processed by means of different chemometric techniques to develop an authentication system for this high quality food product. Honey spectra were obtained in a fast and single way, and they were pretreated by means of standard normal variate transformation in order to remove the influence of particle size, scattering and other factors, and prior to their use as input data. As the first step in chemometric study, display techniques such as principal component analysis and cluster analysis were applied in order to demonstrate that the NIR data contained useful information to develop a pattern recognition classification system to authenticate honeys with PGI. The second step consisted in the application of different pattern recognition techniques (such as D-PLS: Discriminant partial least squares regression; SIMCA: Soft independent modelling of class analogy; KNN: K-nearest neighbours; and MLF-NN: Multilayer feedforward neural networks) to derive diverse models for PGI-honey class with the objective of detecting possible falsification of these high-quality honeys. Amongst all the classification chemometric procedures, SIMCA achieved to be the best PGI-model with 93.3% of sensitivity and 100% of specificity. Therefore, the combination of NIR information data with SIMCA developed a single and fast method in order to differentiate between genuine PGI-Galician honey samples and other commercial honey samples from other origins that, due to their lower price, could be used as substrates for falsification of genuine PGI ones.

Carbon nanotubes as solid-phase extraction sorbents prior to atomic spectrometric determination of metal species: a review.

New materials have significant impact on the development of new methods and instrumentation for chemical analysis. From the discovery of carbon nanotubes in 1991, single and multi-walled carbon nanotubes--due to their high adsorption and desorption capacities--have been employed as sorption substrates in solid-phase extraction for the preconcentration of metal species from diverse matrices. Looking for successive improvements in sensitivity and selectivity, in the past few years, carbon nanotubes have been utilized as sorbents for solid phase extraction in three different ways: like as-grown, oxidized and functionalized nanotubes. In the present paper, an overview of the recent trends in the use of carbon nanotubes for solid phase extraction of metal species in environmental, biological and food samples is presented. The determination procedures involved the adsorption of metals on the nanotube surface, their quantitative desorption and subsequent measurement by means of atomic spectrometric techniques such as flame atomic absorption spectrometry, electrothermal atomic absorption spectrometry or inductively coupled plasma atomic emission spectrometry/mass spectrometry, among others. Synthesis, purification and types of carbon nanotubes, as well as the diverse chemical and physical strategies for their functionalization are described. Based on 140 references, the performance and general properties of the applications of solid phase extraction based on carbon nanotubes for metal species atomic spectrometric determination are discussed.

Determination of Cr and Ni in Orujo spirit samples by ETAAS using different chemical modifiers.

Several analytical methods are proposed for chromium and nickel determination in Orujo spirit samples using ETAAS. Permanent chemical modifiers such as W, Ir, Ru, W-Ir and W-Ru were comparatively studied in relation to the common chemical modifier employed, Pd(NO3)2-Mg(NO3)2. Taking into account the analytical performance, the method based on the use of Ru as a permanent modifier was selected for further direct Cr determinations in Orujo samples. In the case of Ni, after comparison among the different methods developed, a method with no modifier which allows the direct interpolation in calibration graphs was chosen. Detection limits of 0.13µgL(-1) and 0.30µgL(-1) were obtained for Cr and Ni, respectively. For all methods developed, recoveries (ranged 98.6-102%) and precision (RSD<10%) were acceptable. The selected methods were applied for the determination of the Cr and Ni contents in 80 representative Orujo Galician samples. The Cr concentrations ranged from

Direct determination of cadmium in Orujo spirit samples by electrothermal atomic absorption spectrometry: comparative study of different chemical modifiers.

In this work, several analytical methods are proposed for cadmium determination in Orujo spirit samples using electrothermal atomic absorption spectrometry (ETAAS). Permanent chemical modifiers thermally coated on the platforms inserted in pyrolytic graphite tubes (such as W, Ir, Ru, W-Ir and W-Ru) were comparatively studied in relation to common chemical modifier mixtures [Pd-Mg(NO3)2 and (NH4)H2PO4-Mg(NO3)2] for cadmium stabilization. Different ETAAS Cd determination methods based on the indicated modifiers have been developed. In each case, pyrolysis and atomization temperatures, atomization shapes, characteristic masses and detection limits as well as other analytical characteristics have been determined. All the assayed modifiers (permanent and conventional) were capable of achieving the appropriate stabilization of the analyte, with the exception of Ru and W-Ru. Moreover, for all developed methods, recoveries (99-102%) and precision (R.S.D. lower than 10%) were acceptable. Taking into account the analytical performance (best detection limit LOD = 0.01 microg L(-1)), the ETAAS method based on the use of W as a permanent modifier was selected for further direct Cd determinations in Orujo samples from Galicia (NW Spain). The chosen method was applied in the determination of the Cd content in 38 representative Galician samples. The cadmium concentrations ranged

Comparison of different permanent chemical modifiers for lead determination in Orujo spirits by electrothermal atomic absorption spectrometry.

Different analytical methods for the determination of lead in Orujo spirits by electrothermal atomic absorption spectrometry (ETAAS) were developed using permanent modifiers (W, Ir, Ru, W-Ir and W-Ru) thermally deposited on platforms inserted in pyrolitic graphite tubes and Pd-Mg(NO(3))(2) conventional modifier mixture. In all cases, the Pb determination was performed without any sample pretreatment or preconcentration steps. The comparison between the chemical modifiers employed has been made in terms of pyrolysis and atomization temperatures, characteristic masses, detection limits, and atomization and background signal shapes. The limits of detection obtained were 0.375, 0.387, 0.109, 0.251 and 0.267ngmL(-1) for W, Ir, Ru, W-Ir and W-Ru, respectively and 0.710ngmL(-1) for Pd-Mg(NO(3))(2). The characteristic masses were 14.1, 11.2, 5.6, 8.3 and 9.3pg for W, Ir, Ru, W-Ir and W-Ru, respectively and 22.2pg for Pd-Mg(NO(3))(2). For all the developed procedures using the different modification systems, the relative standard deviations (<10%) and the analytical recoveries (95-103%) were acceptable. The more suitable methods for Pb determination in distillate spirits were those using permanent modifiers in contrast with classical Pd-Mg(NO(3))(2). The best analytical performance was achieved for W, Ir and W-Ir methods, which were applied to lead determination in Orujo spirit samples from Galicia (NW Spain). The Pb concentrations found in the analyzed samples were comprised in the range (

Direct and combined methods for the determination of chromium, copper, and nickel in honey by electrothermal atomic absorption spectroscopy.

In the present work, direct methods for the determination of chromium, copper, and nickel in honey by electrothermal atomic absorption spectroscopy were developed using experimental design as an optimization tool. Once the optimum conditions for the individual methods were established, a direct method for the combined determination of the three elements was optimized using the response surface tool. Palladium was used as chemical modifier in all cases. Honey was diluted in water, hydrogen peroxide, and nitric acid. Triton X-100 was added to minimize the matrix effect and the viscosity of the sample. The RSD (better than 10%) and the analytical recovery (98-103%) were acceptable for all of the developed methods. Calibration graphs were used in the four methods to determine the concentration of the analytes in the sample. The detection limits of the combined method (0.21, 0.35, and 0.37 microg L(-)(1) for Cr, Cu, and Ni, respectively) were similar to those obtained for the individual methods (LOD = 0.17, 0.21, 0.33 microg L(-)(1) for Cr, Cu, and Ni, respectively). The direct-combined proposed method has been applied to the determination of chromium, copper, and nickel content in representative honey samples from Galicia (northwestern Spain). The concentrations found in the analyzed samples were in the range of (5.75 +/- 0.64)-(26.4 +/- 0.38) ng g(-)(1) of Cr, (79 +/- 7.8)-(2049 +/- 80) ng g(-)(1) of Cu, and (12.6 +/- 1.36)-(172 +/- 6.88) ng g(-)(1) of Ni.

Comparison of palladium-magnesium nitrate and ammonium dihydrogenphosphate modifiers for cadmium determination in honey samples by electrothermal atomic absorption spectrometry.

The occurrence of certain trace elements, such as cadmium, in honey bee can be considered as an indication of environmental pollution. In the present work, two methods for Cd determination in honey by electrothermal atomic absorption spectrometry, using palladium-magnesium nitrate and ammonium dihydrogenphosphate as chemical modifiers, have been developed. In none of these cases honey samples required pretreatment. Honey was diluted in water (20% w/v), and hydrogen peroxide, nitric acid, and Triton X-100 were added to minimize the matrix effect. For the first method, 21.6 microg of palladium and 4.5 microg of magnesium were added as chemical modifier; for the second method, 60 microg of ammonium dihydrogenphosphate were employed. The limits of detection obtained were 0.32 ng g(-1) for ammonium dihydrogenphosphate method and 0.54 ng g(-1) for palladium-magnesium nitrate method. The characteristic mass was 0.7 and 1.0 pg for ammonium dihydrogenphosphate and palladium-magnesium nitrate methods, respectively. The relative standard deviation (<10%) and the analytical recovery (98-105%) were comparable in both methods. The optimised methods were applied to the determination of the cadmium content in unpolluted Galician honey samples. Cd has been detected the analysed samples in the range (n.d.-4.3 ng g(-1)).