Silver nanoparticles (AgNP) are emerging pollutants. The use of novel materials such as Cu-(benzene 1,3,5-tricarboxylate, BTC) Metal-Organic Framework (MOFs), for AgNP adsorption and their removal from aqueous solutions has been studied.... more
Silver nanoparticles (AgNP) are emerging pollutants. The use of novel materials such as Cu-(benzene 1,3,5-tricarboxylate, BTC) Metal-Organic Framework (MOFs), for AgNP adsorption and their removal from aqueous solutions has been studied. The effect of different parameters was followed and isotherm model was suggested. MOFs adsorbed fast and efficiently AgNP in the range C0 < 10 mg L(-1), being Freundlich isotherm (R = 0.993) these data fitted to. Among studied parameters a remarkable effect of chloride on sorption was found, thus their possible interactions were considered. The high adsorption efficiency of AgNP was achieved and it was found to be very fast. The feasibility of adsorption on Cu-(BTC) was proved in spiked waters. The results showed the potential interest of new material as adsorbent for removing AgNP from environment.
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A new Cotton@Fe-BTC composite formed by Fe-BTC (BTC-H3 : trimesic acid) metal framework (Fe-BTC MOF loading as high 38 wt %) supported by cellulose fibre is synthesised in aqueous media using a simple and green preparation method,... more
A new Cotton@Fe-BTC composite formed by Fe-BTC (BTC-H3 : trimesic acid) metal framework (Fe-BTC MOF loading as high 38 wt %) supported by cellulose fibre is synthesised in aqueous media using a simple and green preparation method, described for the first time in this manuscript. This new strategy relies on the synergetic effect of the pure cellulose and MOFs frameworks resulting in hybrid nanofibers of MOFs@cellulose composite. A complete characterization of the composite material reveals its structural similarity to MIL-100(Fe), a Fe-BTC material. The Cotton@Fe-BTC composite potential use as an eco-friendly and low-cost adsorbent was evaluated for its adsorptive performance for the removal of dyes belonging to the triarylmethane dye family (Malachite Green (MQ), Brilliant Green (BG), Pararosaniline (PR), Basic Fuchsine (BF), Crystal Violet (CV), Methyl Green (Met-G), Victoria Blue B (VB), Acid Fuchsin (AF) and Aniline Blue (AB)) in aqueous solution. The fast kinetics and high dye removal efficiencies ( > 90%) obtained in aqueous solutions. The structure of Cotton@Fe-BTC netwok, contributed to the remarkable adsorption properties towards a variety of triphenylmethanedyes. The interparticle studies showed two main steps in the dye’s adsorption processes, with the exception of AF and BG. The equilibrium adsorption capacities qe (mg/g) follow the order: AF (3.64) < Met-G (3.70) < AB (4.87) < PR (5.52) < BF (5.76) < Met-G (7.22) < CV (9.63) < BG (16.34). However, going insight the adsorption mechanisms, it was remarkable the finding that the reaction paths taking into account the influence of water molecules on the anionic dye adsorption, through the so-called solvation/desolvation penalty processes, may not be ignored. The easy preparation and manipulation of Cotton@Fe-BTC network as well as its stability and excellent performance for the adsorption makes this material a good candidate for a broad range of applications.
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Research Interests: Engineering, Computer Science, Principal Component Analysis, Biology, Neural Network, and 15 moreMedicine, Discriminant Analysis, Classification, Cluster Analysis, Cultivar, Plant Roots, CHEMICAL SCIENCES, Phenols, Plant extracts, Agricultural and Food Chemistry, Onions, Polyphenol, Artificial Neural Network, Pungency, and Allium
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Abstract The direct synthesis of nano-{Fe-BTC} MOFs was performed following green chemistry rules. This nanomaterial has been characterized by several techniques showing structural similarities with commercial Fe-BTC MOFs, although it has... more
Abstract The direct synthesis of nano-{Fe-BTC} MOFs was performed following green chemistry rules. This nanomaterial has been characterized by several techniques showing structural similarities with commercial Fe-BTC MOFs, although it has greater porosity due to the presence of mesopores and micropores, that can make it an efficient adsorbent for fluorescent anionic dyes through electrostatic and π-π interactions between dye and nano-{Fe-BTC}. The adsorption isotherms fit the Freundlich model: tetrabromo-fluorescein(Br-FL) has the highest KF value, followed by dichloro-fluorescein(Cl-FL) and fluorescein(FL). The kinetic study suggests that the adsorption onto nano-{Fe-BTC} follows the pseudo-second-order model and the adsorption capacities follow the order Br-FL (qe 0.836 mg·g−1) > FL (qe 0.106 mg·g−1) ~Cl-FL (qe 0.100 mg·g−1), pH = 4. The use of methanol (5% NH3) allows recoveries of the dyes from nano-{Fe-BTC} ranging from 90% to100%. The presence of inorganic ions and organic substances in the water solution does not affect the adsorption of the dyes even when possible interfering species were present at concentrations that were up to 109 times higher than that of the dyes. The method was successfully applied to remove the target dyes from spiked water samples, showing the potential of high porous nano-{Fe-BTC} MOFs as a promising adsorbent for the effective removal of dyes from waters.
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a Departamento de Química. Unidad Departamental de Química Analítica, Facultad de Ciencias, Universidad de La Laguna, Tenerife, Spain. b Inorganic Chemistry Area, Section of Chemistry Faculty of Science; Instituto Universitario de... more
a Departamento de Química. Unidad Departamental de Química Analítica, Facultad de Ciencias, Universidad de La Laguna, Tenerife, Spain. b Inorganic Chemistry Area, Section of Chemistry Faculty of Science; Instituto Universitario de BioOrgánica “Antonio González”, University of La Laguna, Tenerife, Spain. c Department de Química. Facultat de Ciències, Universitat de Girona, C/ Ma Aurèlia Capmany, 69, 17003 Girona, Spain d Department of Chemistry, Faculty of Science, Masaryk University, Kamenice 5/A14, 625 00 Brno, Czech Republic.
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ABSTRACT Capillary zone electrophoresis (CZE) was used for the separation of humic acids. The influence of the buffer solution on the separation of a commercial humic acid was studied. The use of an 8 mmol l−1 HCl-59.8 mmol l−1l-alanine... more
ABSTRACT Capillary zone electrophoresis (CZE) was used for the separation of humic acids. The influence of the buffer solution on the separation of a commercial humic acid was studied. The use of an 8 mmol l−1 HCl-59.8 mmol l−1l-alanine buffer (pH 3.17) leads to the separation of humic acids into two fractions. The composition and pH of this buffer and some instrumental parameters such as voltage, injection volume and wavelength of detection were optimized and the quality parameters of the method were determined. Two further commercial humic acids were assayed. The one that showed the highest peak signal was used as a reference for the rough quantification of the others.
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This contribution presents a comparative study of the use of PLS and ANNs to analyze A and C mixtures using UV-Vis derivative spectra. The optimum ANN architecture enabling to model the system was established by means of TRAJAN 6.0... more
This contribution presents a comparative study of the use of PLS and ANNs to analyze A and C mixtures using UV-Vis derivative spectra. The optimum ANN architecture enabling to model the system was established by means of TRAJAN 6.0 program. Several algorithms (Back propagation, Conjugate gradients, Quick propagation, and Delta-Bar Delta algorithm) were used for the training of the ANN to obtain a reliable model. With help of a suitable experimental design in combination with soft ANN modelling, the concentration of both A and C in mixtures can be quantified with an excellent accuracy (about 1 %). The quality of the testing set was evaluated on the basis of the average root mean square error for prediction (RMSEP) calculated from true and found values of A and C concentrations (RMSEP = 0.07 for A and 0.09 for C). It was found that ANN gives better results for the first and second derivative spectra than for original spectra. Furthermore, in comparison with PLS the ANN provides a more reliable and precise approach in the multicomponent analysis of A and C mixtures, where a number of different interactions take place.
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The chemistry of gold nanoparticles (GNPs) represents fascinating interdisciplinary field of research with applications in physics, chemistry, nanotechnology, and medicine, especially. GNPs are also used for the synthesis of novel... more
The chemistry of gold nanoparticles (GNPs) represents fascinating interdisciplinary field of research with applications in physics, chemistry, nanotechnology, and medicine, especially. GNPs are also used for the synthesis of novel nano-structured materials such as nanocomposites with graphene, carbon nano-tubes and/or fullerenes. Nanodiamonds (NDs) show unique mechanical, thermal and electrical properties which make them promising molecular building blocks in nanotechnology. Because of their biocompatibility and non-toxicity [1], NDs are used as drug carriers and building blocks e.g., for the fabrication of tissue scaffolds and surgical implants, etc. Metal carbides are extensively applied in industry. For a long time it was believed that gold is not forming carbides. Matthew in 1900 reported for the first time gold carbide (Au2C2) [2]. The formation of gold carbides via laser ablation synthesis was preliminarily indicated in our laboratory [3, 4]. Nowadays, it is known that i) gold forms not only carbides but also aurides and ii) gold-carbon interaction is important for development of electronic devices. The aim of this work is to study the formation of gold carbides via laser ablation synthesis (LAS) using as a precursor a kind of nanocomposite of GNPs with NDs. The GNPs-NDs nanocomposite (Fig. 1 a) was prepared and characterized by atomic force and transmission electron microscopy, energy dispersive X-ray spectroscopy and mass spectrometry. Laser ablation synthesis of gold carbides (Fig. 2) was carried out by laser desorption ionisation time-of-flight mass spectrometry (LDI-TOF-MS). Example of mass spectrum indicating the formation of singly charged AumCn+ clusters is given in Fig. 1 b. Gold carbides AuCn+ (n = 1-11), Au2Cn+ (n = 1-16) and Au3Cn+ (n = 1-10) and also some gold aurides were observed. The structure of observed AumCn clusters most probably corresponds to gold carbides, but also endohedral supramolecular complex formation, e.g., Au@C10 is not excluded (Fig. 3) [5]. Such possibility was supported by modelling via semi-empirical approach using the HYPERCHEMTM program (release 5.1, 1998) from Hyper-cube Inc. (Gainesville, FL, USA). The confirmation of diamond doped structure with gold atom would mean the first experimental evidence of gold-doped NDs. Concluding, laser ablation of GNPs-NDs nanocomposite leads to synthesis of Au-C clusters. Stoichiometry of altogether 37 gold carbides was established while also some gold aurides were formed probably from partially hydrogenated NDs. It is suggested that some “gold carbides” might be gold-modified diamonds or gold-diamond endohedral complexes. Results concerning the synthesis via laser ablation might initiate development of new Au-C materials with specific properties.
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Using PCA and CA humic acids can be classified and differences in Antarctica samples from the others can be seen.
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Supramolecular chemistry deals with the study of organized molecular systems in which the molecules or ions are held together by non-covalent interactions [1, 2, 3]. The reversibility of such interactions makes supramolecular “dynamic”... more
Supramolecular chemistry deals with the study of organized molecular systems in which the molecules or ions are held together by non-covalent interactions [1, 2, 3]. The reversibility of such interactions makes supramolecular “dynamic” systems. This is the key principle on which the design of new molecular machines is based. Examples are given in Fig. 1-2.Also, the labile interactions between particular molecules and drug molecule are the way to develop new drug carriers which is nowadays topic of a high importance in medicine. The formation of supramolecular complexes is usually assisted by carrying out their synthesis preparing sufficient amount of the products and examining them by nuclear magnetic resonance (NMR) or other classical analytical techniques. This can be tedious and laborious process and might require rather high quantity of the reagents. Matrix Assisted Laser Desorption Ionisation (MALDI) and/or Surface Assisted Laser Desorption Ionisation (SALDI) Time Of Flight (TOF) mass spectrometry are traditionally used in Proteomics and Bio-Analytics. We have applied MALDI and SALDI for the fast screening to find out the formation of supramolecular complexes and/or to search for drug carriers. For this purpose, mass spectrometric analysis was used in combination with combinatorial experiments mixing the reactants, either in aqueous or organic phase and the products were then examined. Reactions can also be done directly on a MS target. In some cases, experimental design (ED) was also used in order to reduce the number of combinatorial experiments. In this work several examples of supramolecular complex formation using as hosts cyclic ethers, cyclodextrines, cucurbit[n]urils etc., and as guests fullerenes, nanoparticles, or drugs like antivirals, cisplatin, etc., will be given and discussed. The advantage is that the experiments can be done using minimal amount of the chemicals (such as 10-5 moles or less) which is important for scarce or expensive substances and materials. The proposed application of MALDI and SALDI TOF mass spectrometry with ED represents an efficient and economic way to search for the formation of new supramolecular complexes and/or for possible drug carriers.
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A fast and simple method for the diagnosis of multiple myeloma by the analysis of peripheral blood plasma mass spectra has been developed. It is based on recording the Matrix Assisted Laser Desorption Ionisation Time Of Flight (MALDI TOF)... more
A fast and simple method for the diagnosis of multiple myeloma by the analysis of peripheral blood plasma mass spectra has been developed. It is based on recording the Matrix Assisted Laser Desorption Ionisation Time Of Flight (MALDI TOF) mass spectra of low mass metabolites/compounds (below 2000 Daltons) and the evaluation of these data using Artificial Neural Networks (ANNs). The method, which does not require the identification of biomarkers, has been verified using clinical database of myeloma positive and negative patients.
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It was found by spectrophotometric kinetic study that the reduction of Au(III) with HA is relatively fast in wide pH range. The redox reaction proceeds at least in two main steps and formed nanogold is stabilized in HA solution similar... more
It was found by spectrophotometric kinetic study that the reduction of Au(III) with HA is relatively fast in wide pH range. The redox reaction proceeds at least in two main steps and formed nanogold is stabilized in HA solution similar like with citrate but at elevated gold concentration a kind of {Aun, HA} aggregate is anyway precipitated. The interaction of nanogold with HA as studied by electrophoresis was found to be relatively weak. But the formation of several peaks indicates the complexicity of the reaction mixture. Mass spectrometry indicates that nanogold is forming adducts of gold with some low molecular weight compounds. Possible explanation is that supramolecular {Aun, HA} aggregates might be decomposed in the process of laser desorption ionization. Taking into account available literature data and the results achieved we can conclude that the both reaction of Au(III) with HA and interaction of nanogold with HA are quite complex. We suggest that reduction of Au(III) with HA goes in several steps via Au(III) and Au(II) and Au(I) to at least 2 different size of Aun clusters. Complexation reaction with Au(II) and Au(I) with HA fractions is not excluded. However, to prove that and to prove also possible formation of {Aun, HA}supramolecules needs further intensive research.
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The contribution shows a comparative study of the use of partial least squares (PLS) and artificial neural networks (ANNs) to analyze nucleic acid bases (adenine - A, cytosine - C, thymine -T) in mixtures by UV-Vis spectrophotometry.... more
The contribution shows a comparative study of the use of partial least squares (PLS) and artificial neural networks (ANNs) to analyze nucleic acid bases (adenine - A, cytosine - C, thymine -T) in mixtures by UV-Vis spectrophotometry. Multivariate calibration based on a suitable experimental design (ED) and soft modeling for the quantitative analysis of fully overlapped ultraviolet spectra of A+C binary and/or A+C+T ternary systems were employed. The optimal ANN architecture, enabling to model the system, was established by means of TRAJAN program. Using the multivariate statistical method SIMCA the linearity of the PLS model for dilute solutions containing two or three bases in acetate buffer (pH 4.7) was proved. A combination of the chemometric methods and derivative spectrophotometry was applied. The ability of ANN and PLS to model binary and ternary systems was evaluated on the basis of the root means square error for prediction (RMSEP) and the agreement factor (AF). For the determination of A, C, and T concentrations in binary and/or ternary mixtures, the relative standard deviation was less than 1 %. High predictive potentials of both chemometric methods have been demonstrated.
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Retinoic acid (RA) is a vitamin A (retinol)-derived, small lipophilic molecule, involved in cell proliferation, differentiation or histogenesis, with important clinical applications, e.g. in leukemia treatment. In this work, we have... more
Retinoic acid (RA) is a vitamin A (retinol)-derived, small lipophilic molecule, involved in cell proliferation, differentiation or histogenesis, with important clinical applications, e.g. in leukemia treatment. In this work, we have analyzed retinoic acid by Laser Desorption Ionization (LDI), Surface Assisted Laser Desorption Ionization (SALDI) or Matrix Assisted Laser Desorption Time Of Flight Mass spectrometry (MALDI TOF MS). A formation of cation radical RA•+ using LDI or the protonated form RA.H+ in MALDI was observed. In addition, we developed and optimized SALDI of RA using various forms of gold nano-particles.[1] Applying SALDI or combination of nano-particles and common matrices (SALDI-MALDI) allowed a highly sensitive determination of RA. In summary, analysis and determination of RA by MS was optimized, allowing for subsequent studies in cells or tissues.
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Laser Desorption Ionisation Time Of Flight Mass Spectrometry (LDI TOFMS) was applied for (i) laser ablation synthesis and (ii) to elucidate structure of chalcognides via analysis of clusters formed via LDI of chalcogenide glasses. E.g.,... more
Laser Desorption Ionisation Time Of Flight Mass Spectrometry (LDI TOFMS) was applied for (i) laser ablation synthesis and (ii) to elucidate structure of chalcognides via analysis of clusters formed via LDI of chalcogenide glasses. E.g., nanogold-Te nano-composite was found as a suitable precursor for laser ablation generation of new gold tellurides. On the other hand, the clusters generated via LDI from chalcogenide glasses, especially from Ge-As-Te and Ge-Sb-Se systems, possess to a certain extend part of the original structure - the following bond were identified in the structures: Ge-As, Ge-Sb, Ge-Se, Ge-Te, As-Te, Sb-Se, Sb-Sb, Se-Se, and Te-Te. Concluding, LDI TOFMS is destructive method but it was proved that it is useful tool for structure elucidation of this kind of inorganic materials.
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Formation of gold carbides from various carbon forms like nanodiamond, graphite, fulleren, carbon nanotubes and nanogold was studied.
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Only a few arsenic phosphides are known. High potential for the generation of new compounds is offered by Laser Ablation Synthesis (LAS) and when Laser Desorption Ionisation (LDI) is coupled with simultaneous Time of Flight Mass... more
Only a few arsenic phosphides are known. High potential for the generation of new compounds is offered by Laser Ablation Synthesis (LAS) and when Laser Desorption Ionisation (LDI) is coupled with simultaneous Time of Flight Mass Spectrometry (TOFMS), immediate identification of the clusters can be achieved. LAS was used for the generation of arsenic phosphides via laser ablation of phosphorus-arsenic mixtures while quadrupole ion trap time-of-flight mass spectrometry (QIT-TOFMS) was used to acquire the mass spectra. Many new AsPclusters (479 binary and 369 mono-elemental) not yet described in the literature were generated in the gas phase and their stoichiometry determined. The likely structures for some of the observed clusters arbitrary selected (20) were computed by DFT optimization. LAS is an advantageous approach for the generation of new AsPclusters, while mass spectrometry was found to be an efficient technique for the determination of cluster stoichiometry. The results achie...
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The content of Cu, Fe, Mn, Zn, Co, Cr, Ni, and Pb were determined in 496 samples of heat-treated canned liver pastes by atomic absorption spectrometry. Canned samples were classified according to the presence or absence of coated varnish... more
The content of Cu, Fe, Mn, Zn, Co, Cr, Ni, and Pb were determined in 496 samples of heat-treated canned liver pastes by atomic absorption spectrometry. Canned samples were classified according to the presence or absence of coated varnish on the inner side of the can. For each sample, two subsamples were taken: one from the area in contact with the side of the can, the other from the center of the container. Univariate (correlation, box and whisker) and multivariate (quality control charts, principal component analysis, and factor analysis) statistical techniques were applied to detect the presence of outliers and for exploratory data analysis. No significant differences (P < 0.05) were found between the subsamples considered, presence or absence of coated varnish, the sampling areas, or countries of origin. The multivariate analysis allows for the interpretation of grouping tendencies in samples. Cr, Ni, and Pb were associated with presence or absence of oxide in the can, and the...
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ABSTRACT Humic acids (HAs) extracted from different organic compost and soil from Argentina have been characterized by capillary electrophoresis (CE) and mass spectrometry. The chemical properties of HAs show changes depending on their... more
ABSTRACT Humic acids (HAs) extracted from different organic compost and soil from Argentina have been characterized by capillary electrophoresis (CE) and mass spectrometry. The chemical properties of HAs show changes depending on their origin (compost, soil). Capillary electrophoresis analyses were carried out using a background electrolyte consisting of boric acid, TRIS and EDTA (BTE). BTE was also modified with cyclodextrins. After optimization of BTE, the best results were obtained when b-cyclodextrin was used. Under optimized separation conditions, the characteristics CE fingerprints of compost derived HAs (CHAs) were studied. CE fingerprints show differences in the composition of the different CHAs. Mass spectra obtained by laser desorption ionization time of flight mass spectrometry show differences between the CHAs and HAs extracted from Argentinean soil. A comparison with the soil standard HAs (International Humic Substances Society) was made. CHAs show mostly compounds in the mass spectra with low m/z values. The typical patterns exhibited in soil HAs of different origin are present in the Argentinean soil HA, i.e. groups of peaks around mass-to-charge (m/z) 800.
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ABSTRACT Trace metals and major cations (Cu, Zn, Fe, Na, K, Ca and Mg) were determined in fish Chromis limbatus by flame and graphite furnace atomic absorption spectrometry. The application of principal component analysis and factor... more
ABSTRACT Trace metals and major cations (Cu, Zn, Fe, Na, K, Ca and Mg) were determined in fish Chromis limbatus by flame and graphite furnace atomic absorption spectrometry. The application of principal component analysis and factor analysis to the data matrix seems to discriminate between major cations and trace metals, accounting for 80% of the total variability. The plot of the scores of metals in the muscle samples on the first two principal components pointed out a differentiation of two groups belonging to different seasons. Cluster analysis (K-nearest neighbor) confirmed the separation between the two season&#39;s groups of samples.
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Artificial Neural Networks (ANN) belonging to the Artificial Intelligence methods play an ever increasing role in modern science. Developed in the 1950s, inspired by the neuron structure and the way how human brain works they have been... more
Artificial Neural Networks (ANN) belonging to the Artificial Intelligence methods play an ever increasing role in modern science. Developed in the 1950s, inspired by the neuron structure and the way how human brain works they have been finding increasingly powerful and exciting applications in all branches of science. The book deals with fundamentals and basic principles of ANN, how to use them, and commented survey of selected examples and/or applications of ANN in Science.
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Se estudian los niveles de contaminacion por hidrocarburos del petroleo en especies marinas endemicas de las costas canarias. Al mismo tiempo se estudia la posibilidad de utilizar dichas especies como organismos indicadores de la... more
Se estudian los niveles de contaminacion por hidrocarburos del petroleo en especies marinas endemicas de las costas canarias. Al mismo tiempo se estudia la posibilidad de utilizar dichas especies como organismos indicadores de la contaminacion. A los resultados obtenidos se aplica el analisis multivariante con el fin de estudiar las relaciones existentes entre las muestras en funcion de sus similitudes y consecuentemente obtener conclusiones en funcion de sus localizaciones geograficas, situacion de vertidos y otras fuentes de contaminacion. A la vista de los resultados obtenidos parece que la aplicacion conjunta del analisis de componentes principales, analisis de factores y de agrupamientos, permite asociar la contaminacion petrogenica con los crudos de procedencia.
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Influence of agronomic variables on quality of tomato
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On selecting a constituent part of MU the "Overview of publishing activities" page will be displayed with information relevant to the selected constituent part. The "Overview of publishing activities" page is not... more
On selecting a constituent part of MU the "Overview of publishing activities" page will be displayed with information relevant to the selected constituent part. The "Overview of publishing activities" page is not available for non-activated items. ... RAMÍREZ GALICIA, Guillermo - ...
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ABSTRACT Correct assessment of tissue histopathology is a necessary prerequisite for any clinical diagnosis. Nowadays, classical methods of histochemistry and immunohistochemistry are complemented by various techniques adopted from... more
ABSTRACT Correct assessment of tissue histopathology is a necessary prerequisite for any clinical diagnosis. Nowadays, classical methods of histochemistry and immunohistochemistry are complemented by various techniques adopted from molecular biology and bioanalytical chemistry. Mass spectrometry profiling or imaging offered a new level of tissue visualization in the last decade, revealing hidden patterns of tissue molecular organization. It can be adapted to diagnostic purposes to improve decisions on complex and morphologically not apparent diagnoses. In this work, we successfully combined tissue profiling by mass spectrometry with analysis by artificial neural networks to classify normal and diseased liver and kidney tissues in a mouse model of primary hyperoxaluria type 1. Lack of the liver l-alanine:glyoxylate aminotransferase catalyzing conversion of l-alanine and glyoxylate to pyruvate and glycine causes accumulation of oxalate salts in various tissues, especially urinary system, resulting in compromised renal function and finally end stage renal disease. As the accumulation of oxalate salts alters chemical composition of affected tissues, it makes it available for examination by bioanalytical methods. We demonstrated that the direct tissue MALDI-TOF MS combined with neural computing offers an efficient tool for diagnosis of primary hyperoxaluria type I and potentially for other metabolic disorders altering chemical composition of tissues.
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Currently, a limited number of gold arsenides have been described, some of which have important industrial applications, Laser ablation synthesis (LAS) has been employed in an attempt to generate some novel gold arsenide compounds. LAS of... more
Currently, a limited number of gold arsenides have been described, some of which have important industrial applications, Laser ablation synthesis (LAS) has been employed in an attempt to generate some novel gold arsenide compounds. LAS of gold arsenides was performed using nano-gold (NG) and arsenic as precursors. The clusters formed during laser desorption ionisation (LDI) were analysed by mass spectrometry using a quadrupole ion trap and reflectron time-of-flight analyser to determine the stoichiometry. UV/VIS spectrophotometry was used to follow possible hydrothermal synthesis of gold arsenides. LAS of NG yielded singly charged gold clusters Aum (+(-)) (m = 1-35). LAS of bulk arsenic and nano-arsenic produced Asn (+(-)) clusters with n = 2-10 and n = 2-20, respectively. Laser ablation of Au-As nano-composites or NG-As mixtures generated Aum (+(-)) (m = 1-12), Asn (+(-)) (n = 3-4), and several series of Aum Asn (+(-)) (m = 1-60, n = 1-18) clusters. Over 450 species of gold arsenide clusters and 212 mixed chlorinated Aum Asn Clx clusters were detected and their stoichiometry determined. Many new gold arsenides were synthesised via LAS for the first time with Au-As composites and NG-As mixtures of different Au:As ratios using mass spectrometry to determine cluster stoichiometry. The resolved stoichiometry of Aum Asn clusters determined in this study could accelerate the development of advanced Au-As nano-materials.
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In supramolecular complexes the molecules or ions are held together by non-covalent interactions: Host + Guest {Host, Guest}. Usually, compounds like cyclic ethers, cyclodextrines, or other macrocycles might act as hosts while various... more
In supramolecular complexes the molecules or ions are held together by non-covalent interactions: Host + Guest {Host, Guest}. Usually, compounds like cyclic ethers, cyclodextrines, or other macrocycles might act as hosts while various organic/inorganic cations, anions, neutral molecules etc. are playing the role of guests. The paper deals with the application of mass spectrometry (MS) for fast screening of variour host-guests combinations in order to find out the formation of supramolecular complexes and/or to search for new potential drug carriers or to decrease their toxicity. MS was done using either matrices, laser desorption ionization (LDI) or surface assisted LDI. Mass spectrometric analysis was used because the reactions can also be done directly on the MS target and several combinations can be examined with the minimum amount of often scarce and expensive reagents. Several examples of supramolecular complex formation using different types of macrocycles (cyclodextrins, cucu...
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Several gold selenium complexes are known (e.g., [Au 2 (Se 2 )(Se 3 )] 2- , [Au 2 (Se 2 )(Se 4 )] 2- and [Au 2 Se 2 (Se 4 ) 2 ] 2- ). Minerals such as fischesserite (Ag 3 AuSe 2 ), kurilite ((Au,Ag) 2 (Te,Se,S) 2 ) and petrovskite... more
Several gold selenium complexes are known (e.g., [Au 2 (Se 2 )(Se 3 )] 2- , [Au 2 (Se 2 )(Se 4 )] 2- and [Au 2 Se 2 (Se 4 ) 2 ] 2- ). Minerals such as fischesserite (Ag 3 AuSe 2 ), kurilite ((Au,Ag) 2 (Te,Se,S) 2 ) and petrovskite ((AuAg)(S,Se)) are found in nature. Laser desorption ionisation time-of-flight mass spectrometry (LDI TOF MS) is powerful technique to generate and study clusters formed during laser ablation of various materials leading to metal chalcogenides [1] or gold carbides [2], for example. The aim of this work is to study the generation of Au m Se n clusters via laser ablation synthesis (LAS) using mixtures of GNPs (or auric acid) with selenium in various molar ratios as precursors. We have found that GNPs are chemisorbed on selenium surface leading to the formation of a kind of nano-composite as confirmed by scanning electron microscope (SEM) analysis. The LAS from various precursors and nano-composites leads to the generation of several series of Au m Se n clust...