Artículos de revistas: "Physico-chemical characterization by fluorescence"

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Daou, Claude, Mervat El Hoz, Amine Kassouf y Bernard Legube. "Multivariate Monitoring of Surface Water Quality: Physico-Chemical, Microbiological and 3D Fluorescence Characterization". Water 12, n.º 6 (11 de junio de 2020): 1673. http://dx.doi.org/10.3390/w12061673.

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The primary objective of this study is to explore a water quality database on two Mediterranean rivers (the Kadisha-Abou Ali and El Jaouz rivers—located in north Lebanon), considering their physicochemical, microbiological and fluorescence characteristics. Principal Component Analysis (PCA) was applied to the matrix gathering physicochemical and microbiological data while the Common Components and Specific Weight Analysis (CCSWA) or ComDim was used for fluorescence excitation-emission matrices (EEMs). This approach provided complementary and valuable information regarding water quality in such complex ecosystem. As highlighted by the PCA and ComDim scores, the Kadisha-Abou Ali River is highly influenced by anthropogenic activities because its watershed districts are intensively populated. This influence reveals the implication of organic and bacteriological parameters. To the contrary, the El Jaouz watershed is less inhabited and is characterized by mineral parameters, which determines its water quality. This work highlighted the relationship between fluorescence EEMs and major water quality parameters, enabling the selection of reliable water quality indicators for the studied rivers. The proposed methodology can surely be generalized to the monitoring of surface water quality in other rivers. Each customized water quality fingerprint should constantly be inspected in order to account for any emerging pollution.

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Staninski, Krzysztof y Stefan Lis. "Photophysical characterization of chosen Ln(III) macromolecular complexes". International Journal of Photoenergy 7, n.º 3 (2005): 147–51. http://dx.doi.org/10.1155/s1110662x0500022x.

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Spectral characterization of N,N′-Bis(2,4-dihydroxobenzylidene)1,2-diaminobenzene (DHDA) complexes with chosen f- and d-metal ions are described. Physico-chemical properties of a series of complexes were studied in methanol solution using UV-VIS, IR and fluorescence spectroscopy. It was found that the excitation and fluorescence spectra of DHDA in water and methanol after being exposed to ultraviolet radiation, show very obvious photochromism. The formation of 1 : 1 complexes between4,4′,4″,4‴-(porphine-5,10,15,20-tetrayl)-tetrakis benzoic acid, (TCPPH2) and La(III), Eu(III) and Yb(III) in methanolic solution, with the use of the spectrophotometric and spectrofluorimetric methods. The conditional stability constants of the complexes were studied by monitoring the spectral changes of energy and intensity of Q bands of the porphyrin.

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Bujor, Alexandru, Victorita Tecuceanu, Anamaria Hanganu y Petre Ionita. "Synthesis and Structural Analysis of a Nitrobenzofurazan Derivative of Dibenzo-18-Crown-6 Ether". Chemistry 4, n.º 4 (9 de diciembre de 2022): 1696–701. http://dx.doi.org/10.3390/chemistry4040110.

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Nitrobenzofurazan derivatives are well known for their fluorescence, whilst crown ethers are known for their complexing capacity toward cationic species. In this study, we present the synthesis and structural characterization of a new derivative containing both nitrobenzofurazan moieties and a crown ether core. The new compound was obtained from dibenzo-18-crown-6 ether, which was first nitrated, reduced to the corresponding amine, and subsequently derivatized with NBD. Structural analyses performed by IR, NMR, UV–Vis, and MS confirmed its structure and physico-chemical behavior toward the complexation of alkaline cations.

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Rabilou Souley Moussa, Zeinabou Mahamadou, Ousmaila Sanda Mamane, Issa Habou, Maman Mousbahou Malam Alma y Ibrahim Natatou. "Physico-chemical, mineralogical and structural characterization of a clay of Tanout (Zinder-Niger)". World Journal of Advanced Research and Reviews 16, n.º 2 (30 de noviembre de 2022): 1077–92. http://dx.doi.org/10.30574/wjarr.2022.16.2.1272.

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The objective of this study is to identify the different mineral phases, the structural and textural properties of natural clay of Tanout in Zinder region (Niger) in order to have mineralogical data allowing its valuation. The methodology is based on a physicochemical characterization by coupling several analysis techniques (preliminary analyses, X-ray fluorescence, X-ray diffraction, thermos- gravimetric analysis, scanning electron microscopy, Brunauer-Emmett-Teller by adsorption of N2 at 77 K). The results from these analyzes show that this clay has a low humidity rate, a low density, a slightly neutral pH in an aqueous medium and a high cation exchange capacity and is mainly composed of SiO2 (68.1%), Al2O3 (17.02%) and Fe2O3 (7.6%) with trace elements, the most important of which are: Zr (4150.6 ppm), Sr (470 ppm), Cu (380.2 ppm) and V (320ppm). It essentially consists of Kaolinite and Montmorillonite with impurities such as quartz and microclines. It has a specific surface of 441.1 m2.g-1 and 2288 m2.g-1 calculated according to the BET and Langmuir methods respectively, with porous volume varying from 0.0157 to 0.2597 cm3.g-1 and of pore size which varies from 1.847 to 6.182 nm calculated according to the methods (Barrett-Joyner-Halenda, Dubinin-Radushkevich, Dubinin-A, Horvath-Kawazoe and Saito-Foley). This clay has an important degree of crystallinity. These characteristics make it a potential material that can be used in water pollution control.

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Sousa, F. K. A., I. A. Silva, W. S. Cavalcanti, Gelmires Araújo Neves y Heber Carlos Ferreira. "Physico-Mineralogical Characterization: Bentonitic Clays Recently Found in Olivedos, Paraíba, Brazil". Materials Science Forum 820 (junio de 2015): 56–59. http://dx.doi.org/10.4028/www.scientific.net/msf.820.56.

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Used in various branches of the industry, bentonitic clays are considered a valuable mineral, used specially in the petroleum industry for manufacturing of fluids used the drilling of petroleum wells in long depth. Recently, a deposit of this valuable mineral was discovered in the town of Olivedos-PB. There are data that prove that this is a very poor and underdeveloped town. So, this work aims at the physico-mineralogical characterization of clays recently discovered and, this way, verify if they present similar characteristics which allow them to replace the clays from Boa Vista-PB, and if they can be used by the industry, thus bringing social development for that town. The characterization was made by means of the analysis of chemical composition by X-ray fluorescence (EDX), thermogravimetric and thermal differential analyses (TG and DTA), X-ray diffraction (XRD), cation-exchange capacity (CEC) and specific area (SA). The results show that the clays recently discovered in Olivedos-PB are polycationic clays, presenting MgO, CaO and K2O content, and that they are constituted by smectitic clay mineral, by quartz and kaolinite.

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Maravelaki, Pagona-Noni, Antonis Theologitis, Meral Budak Unaler, Chrysi Kapridaki, Kali Kapetanaki y James Wright. "Characterization of Ancient Mortars from Minoan City of Kommos in Crete". Heritage 4, n.º 4 (22 de octubre de 2021): 3908–18. http://dx.doi.org/10.3390/heritage4040214.

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This work characterizes ancient mortars used in construction of the Bronze Age Minoan port at Kommos in Crete. The port dates from c. 1850 BCE with port facilities at the harbor and residences on the Central hillside and the Hilltop. A Greek, Phoenician, and Roman sanctuary overlies the administrative center. The first step collected representative samples from the different construction phases, previous conservation interventions, exposure to different environmental factors, and different material composition. From these 10 mortar samples were analyzed using stereo- and digital microscopy, X-ray diffraction (XRD), X-ray Fluorescence (XRF), and Fourier Transform Infrared spectroscopy (FTIR) to determine texture, morphology, mineralogical, and physico-chemical properties. The physico-chemical and mineralogical analyses divided the samples into two groups: lime binder mortars and earthen binder mortars. The main minerals identified in the samples are calcite, quartz, dolomite, illite, albite, kaolinite, and vermiculite. Analysis of local clay showed that local materials were used in the production of these mortars. The analysis of mortar samples with stereomicroscopy, XRF, and FTIR showed that the samples are mainly composed of calcite and silicates in major quantities along with aluminum, magnesium, and iron oxide in minor quantities. A wide variety of local aggregates and ceramic fragments were used in the production of these ancient mortars. The mortar condition resulted in a decay state that needs conservation interventions. This characterization of the ancient mortars was important for the design of compatible restoration mortars.

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Dadi, Nitin Chandra teja, Matúš Dohál, Veronika Medvecká, Juraj Bujdák, Kamila Koči, Anna Zahoranová y Helena Bujdáková. "Physico-Chemical Characterization and Antimicrobial Properties of Hybrid Film Based on Saponite and Phloxine B". Molecules 26, n.º 2 (10 de enero de 2021): 325. http://dx.doi.org/10.3390/molecules26020325.

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This research was aimed at the preparation of a hybrid film based on a layered silicate saponite (Sap) with the immobilized photosensitizer phloxine B (PhB). Sap was selected because of its high cation exchange capacity, ability to exfoliate into nanolayers, and to modify different surfaces. The X-ray diffraction of the films confirmed the intercalation of both the surfactant and PhB molecules in the Sap film. The photosensitizer retained its photoactivity in the hybrid films, as shown by fluorescence spectra measurements. The water contact angles and the measurement of surface free energy demonstrated the hydrophilic nature of the hybrid films. Antimicrobial effectiveness, assessed by the photodynamic inactivation on hybrid films, was tested against a standard strain and against methicillin-resistant bacteria of Staphylococcus aureus (MRSA). One group of samples was irradiated (green LED light; 2.5 h) and compared to nonirradiated ones. S. aureus strains manifested a reduction in growth from 1-log10 to over 3-log10 compared to the control samples with Sap only, and defects in S. aureus cells were proven by scanning electron microscopy. The results proved the optimal photo-physical properties and anti-MRSA potential of this newly designed hybrid system that reflects recent progress in the modification of surfaces for various medical applications.

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Dadi, Nitin Chandra teja, Matúš Dohál, Veronika Medvecká, Juraj Bujdák, Kamila Koči, Anna Zahoranová y Helena Bujdáková. "Physico-Chemical Characterization and Antimicrobial Properties of Hybrid Film Based on Saponite and Phloxine B". Molecules 26, n.º 2 (10 de enero de 2021): 325. http://dx.doi.org/10.3390/molecules26020325.

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This research was aimed at the preparation of a hybrid film based on a layered silicate saponite (Sap) with the immobilized photosensitizer phloxine B (PhB). Sap was selected because of its high cation exchange capacity, ability to exfoliate into nanolayers, and to modify different surfaces. The X-ray diffraction of the films confirmed the intercalation of both the surfactant and PhB molecules in the Sap film. The photosensitizer retained its photoactivity in the hybrid films, as shown by fluorescence spectra measurements. The water contact angles and the measurement of surface free energy demonstrated the hydrophilic nature of the hybrid films. Antimicrobial effectiveness, assessed by the photodynamic inactivation on hybrid films, was tested against a standard strain and against methicillin-resistant bacteria of Staphylococcus aureus (MRSA). One group of samples was irradiated (green LED light; 2.5 h) and compared to nonirradiated ones. S. aureus strains manifested a reduction in growth from 1-log10 to over 3-log10 compared to the control samples with Sap only, and defects in S. aureus cells were proven by scanning electron microscopy. The results proved the optimal photo-physical properties and anti-MRSA potential of this newly designed hybrid system that reflects recent progress in the modification of surfaces for various medical applications.

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9

Ayanda, Fatai Arolu, Mohd Firdaus Mohd Anuar, Syaharudin Zaibon y Shamshuddin Jusop. "The Physico-Chemical and Mineralogical Characterization of Mg-Rich Synthetic Gypsum Produced in a Rare Earth Refining Plant". Sustainability 13, n.º 9 (26 de abril de 2021): 4840. http://dx.doi.org/10.3390/su13094840.

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The physical, chemical and mineralogical characterization of the constituents of magnesium-rich synthetic gypsum produced in a rare earth-refining plant located in Gebeng, Pahang, Malaysia was conducted through elemental chemical analysis, scanning electron microscopy with Energy Dispersive X-ray (EDX)-analyzer, thermal analysis, X-ray fluorescence and X-ray diffraction. The crystalline nature of the by-product was studied using FTIR spectroscopy. Elemental analysis confirmed the presence of Ca and Mg, which are essential macronutrients required by plants and this Ca alongside the high pH (9.17) of MRSG may confer on the material a high acid neutralization capacity. From the result, it was observed that the studied by-product is a heterogeneous crystalline material comprising of gypsum (CaSO4.2H2O) and other major components such as calcium (magnesium) compounds (hydroxide, oxide, silicates, and carbonate) and sulfur. These aggregates may contribute to give an acid neutralization capacity to MRSG. The XRD study of MRSG indicated a high content of gypsum (45.4%), shown by the d-spacing of 7.609 Å (2-theta 11.63) in the diffractogram. The infrared absorption spectra of MRSG indicate close similarities to mined gypsum. The results of the characterization indicated that MRSG has valuable properties that can promote its use in amending soil fertility constraints on nutrient-deficient tropical acid soils.

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Sena, Andressa S., Bacus Nahime, Elton C. Lima, Fausto A. Lobo, Jorge L. Akasaki y Igor S. dos Santos. "Characterization of briquettes produced from eucalyptus wood waste generated in agro-industries". Revista Brasileira de Engenharia Agrícola e Ambiental 25, n.º 11 (noviembre de 2021): 794–98. http://dx.doi.org/10.1590/1807-1929/agriambi.v25n11p794-798.

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ABSTRACT Boilers are widely used by industries and thermoelectric plants to generate renewable energy. However, when biomass is consumed, residues are generated, which for the most part cannot be discarded appropriately. This study investigated the reuse of eucalyptus wood waste with the goal of transforming the residue into resistant and durable briquettes for reuse in furnaces and boilers. The physico-chemical properties of the residue were studied in terms of chemical composition by X-ray fluorescence, and its crystalline structure was evaluated by X-ray diffraction. Both thermogravimetric analysis and differential thermogravimetric analysis were used to characterize the thermal decomposition of the wood waste residue. The residue was compacted in a universal press with sufficient humidity to fabricate briquettes under different conditions of mechanical pressure. Apparent density, durability, and burning tests were carried out on the briquettes. The maximum temperature reached during burning is dependent on the fabrication compaction pressure. The briquettes proved suitable for burning in boilers and furnaces, and their durability is advantageous for handling, reuse, and transportation.

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Chung, Chih Kit, Jomarien García-Couce, Yaima Campos, Dana Kralisch, Katja Bierau, Alan Chan, Ferry Ossendorp y Luis Javier Cruz. "Doxorubicin Loaded Poloxamer Thermosensitive Hydrogels: Chemical, Pharmacological and Biological Evaluation". Molecules 25, n.º 9 (8 de mayo de 2020): 2219. http://dx.doi.org/10.3390/molecules25092219.

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(1) Background: doxorubicin is a potent chemotherapeutic agent, but it has limitations regarding its side effects and therapy resistance. Hydrogels potentially deal with these problems, but several characterizations need to be optimized to better understand how hydrogel assisted chemotherapy works. Poloxamer 407 (P407) hydrogels were mixed with doxorubicin and physico-chemical, biological, and pharmacological characterizations were considered. (2) Methods: hydrogels were prepared by mixing P407 in PBS at 4 °C. Doxorubicin was added upon solutions became clear. Time-to-gelation, hydrogel morphology, and micelles were studied first. The effects of P407-doxorubicin were evaluated on MC-38 colon cancer cells. Furthermore, doxorubicin release was assessed and contrasted with non-invasive in vivo whole body fluorescence imaging. (3) Results: 25% P407 had favorable gelation properties with pore sizes of 30–180 µm. P407 micelles were approximately 5 nm in size. Doxorubicin was fully released in vitro from 25% P407 hydrogel within 120 h. Furthermore, P407 micelles strongly enhanced the anti-neoplastic effects of doxorubicin on MC-38 cells. In vivo fluorescence imaging revealed that hydrogels retained fluorescence signals at the injection site for 168 h. (4) Conclusions: non-invasive imaging showed how P407 gels retained drug at the injection site. Doxorubicin P407 micelles strongly enhanced the anti-tumor effects.

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Ion, Rodica Mariana, Lorena Iancu, Madalina Elena David, Ramona Marina Grigorescu, Bogdan Trica, Raluca Somoghi, Sorina Florentina Vasile, Ioana Daniela Dulama, Anca Irina Gheboianu y Sorin Tincu. "Multi-Analytical Characterization of Corvins’ Castle—Deserted Tower. Construction Materials and Conservation Tests". Heritage 3, n.º 3 (20 de agosto de 2020): 941–64. http://dx.doi.org/10.3390/heritage3030051.

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The aim of this paper is to analyze the construction materials (mortars) of an architectural monument (Deserted Tower (Lilly Tower) from Corvins’ Castle, Romania). The mortars were characterized following a multidisciplinary approach, combining macroscopic observation with petrographic microscopy, mineralogical analysis (X-ray diffraction) and elemental analysis (X-ray fluorescence), hydric properties, and color of representative samples of the monument. The results revealed the use of gypsum mortars (produced by lumps with higher Fe content), with minor concentrations of crystalline dolomites of the Southern Carpathians, calcite, and quartz. The materials’ effective porosity and their water absorption capacity were high. A possible solution to consolidate the damaged area with some consolidation products (hydroxyapatite carbonate and its derivatives with Ag and Sr) was investigated, too. The interactions between the mortar’s specimens and the effectiveness of the consolidation treatments were evaluated by physico-chemical analyses (molecular structure by X-ray powder diffraction (XRPD), wavelength dispersive X-ray fluorescence (WDXRF), dynamic light scattering (DLS)), morphological characterization by microscopic techniques as SEM-EDS, TEM, and physical and mechanical investigations (peeling test and compressive strength). Results were drawn based on historical, in situ observations, and analytical data, and put into evidence the composition, high weathering degree, and the possibility to surface consolidate with Sr-CHAp.

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Uspenskaya, Elena V., Anton V. Syroeshkin, Tatiana V. Pleteneva, Ilaha V. Kazimova, Tatiana V. Grebennikova, Irina T. Fedyakina, Varvara V. Lebedeva et al. "Nanodispersions of Polyelectrolytes Based on Humic Substances: Isolation, Physico-Chemical Characterization and Evaluation of Biological Activity". Pharmaceutics 13, n.º 11 (18 de noviembre de 2021): 1954. http://dx.doi.org/10.3390/pharmaceutics13111954.

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Natural polyelectrolytes, including in the form of complexes with colloidal particles, are increasingly used in pharmacy due to the possibility of regulated attachment of medicinal substances and their targeted delivery to the target organ. However, the formation, stability, and molecular-mass characteristics of polyelectrolyte nanodispersions (ND) vary depending on the nature and composition of the medium of their origin. This is due to the lack of standardized approaches to quality control and regulatory documentation for most natural ND. In this paper, we first introduced the isolation, followed by investigations into their physico-chemical properties and bioactivity. Using the dried droplet method, we were able to detect the “coffee ring effect”. Fractographic studies of the surface structure of EHA and FA dried samples using SEM showed its heterogeneity and the presence of submicron particles encapsulated in the internal molecular cavities of polyelectrolyte. FTIR spectroscopy revealed the ND chemical structure of benzo-α-pyron and benzo-γ-pyron, consisting of nanoparticles and a branched frame part. The main elements detected by X-ray fluorescence in humic substance extract and fulvic acid include Si, P, S, K, Ca, Mn, Fe, Cu, Zn, whereas Fe is in high concentrations. The UV-spectra and fluorescent radiation demonstrated the possibility of studying the effect of the fulvate chromone structure on its optical properties. It is shown that dilution of the initial solutions of polyelectrolytes 1:10 contributes to the detection of smaller nanoparticles and an increase in the absolute value of the negative ζ-potential as a factor of ND stability. A study of the EHS effect on the SARS-CoV-2 virus infectious titer in the Vero E6 cell showed the effective against virus both in the virucidal scheme (the SI is 11.90–22.43) and treatment/prevention scheme (the SI is 34.85–57.33). We assume that polyelectrolyte ND prevent the binding of the coronavirus spike glycoprotein to the receptor. Taking into account the results obtained, we expect that the developed approach can become unified for the standardization of the ND natural polyelectrolytes complex, which has great prospects for use in pharmacy and medicine as a drug with antiviral activity.

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Sarika, Raj y Dhesingh Ravi Shankaran. "Fabrication and Characterization of Multifunctional Curcumin Loaded Poly(methyl methacrylate) Fluorescent Nanofiber Membrane". Journal of Nanoscience and Nanotechnology 21, n.º 4 (1 de abril de 2021): 2246–53. http://dx.doi.org/10.1166/jnn.2021.19070.

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This work aims at the development of curcumin loaded poly(methyl methacrylate) (CC-PMMA) fluorescent nanofiber membrane and the evaluation of its multifunctional characteristics. The nanofibers were created by electrospinning method. The conditions of the spinning were optimized to obtain beadless and smooth nanofibers. The physico-chemical characteristics of the nanofibers were studied by various techniques including, polarizing light microscope, FT-IR, inverted epi fluorescence microscope and HR-TEM. The HR-TEM results confirm the formation of nanofibers with the diameter in the range of 90–200 nm. The average width of PMMA and CC-PMMA nanofibers are ˜90±0.02 nm and ˜110±0.01 nm, respectively. The CC-PMMA nanofibers exhibited the fluorescence shift with an emission around 520 nm. The multifunctional characteristic of CC-PMMA nanofiber was evaluated for sensor and antibacterial applications. The CC-PMMA nanofiber membrane showed a visible color variation from yellow to red on interaction with ammonia. This colorimetric response to ammonia is highly selective and there was no any interference from other related organic vapors. In addition, it showed good antibacterial activities for Gram-positive and Gram-negative bacteria (zone of inhibition of 27 mm for S. aureus). This is the initial research report in the combination of curcumin and PMMA nanofiber. The multifunctionality of the CC-PMMA nanofibers could be exploited for various applications including sensors, antibacterial coatings, air filtration and drug delivery.

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Moacă, Elena-Alina, Claudia Geanina Watz, Daniela Flondor (Ionescu), Cornelia Păcurariu, Lucian Barbu Tudoran, Robert Ianoș, Vlad Socoliuc et al. "Biosynthesis of Iron Oxide Nanoparticles: Physico-Chemical Characterization and Their In Vitro Cytotoxicity on Healthy and Tumorigenic Cell Lines". Nanomaterials 12, n.º 12 (10 de junio de 2022): 2012. http://dx.doi.org/10.3390/nano12122012.

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Iron oxide nanoparticles were synthesized starting from two aqueous extracts based on Artemisia absinthium L. leaf and stems, employing a simplest, eco-friendliness and low toxicity method—green synthesis. The nanoparticles were characterized by powder X-ray diffraction (XRD), Fourier transformed infrared spectroscopy (FT-IR), X-ray fluorescence analysis (XRF), thermal analysis (TG/DSC), and scanning electron microscopy (SEM). Lack of magnetic properties and the reddish-brown color of all the samples confirms the presence of hematite as majority phase. The FTIR bands located at 435 cm−1 and 590 cm−1, are assigned to Fe-O stretching vibration from hematite, confirming the formation of α-Fe2O3 nanoparticles (NPs). The in vitro screening of the samples revealed that the healthy cell line (HaCaT) presents a good viability (above 80%) after exposure to iron oxide NPs and lack of apoptotic features, while the tumorigenic cell lines manifested a higher sensitivity, especially the melanoma cells (A375) when exposed to concentration of 500 µg/mL iron oxide NPs for 72 h. Moreover, A375 cells elicited significant apoptotic markers under these parameters (concentration of 500 µg/mL iron oxide NPs for a contact time of 72 h).

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Mansuriya, Bhargav D. y Zeynep Altintas. "Carbon Dots: Classification, Properties, Synthesis, Characterization, and Applications in Health Care—An Updated Review (2018–2021)". Nanomaterials 11, n.º 10 (27 de septiembre de 2021): 2525. http://dx.doi.org/10.3390/nano11102525.

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Carbon dots (CDs) are usually smaller than 10 nm in size, and are meticulously formulated and recently introduced nanomaterials, among the other types of carbon-based nanomaterials. They have gained significant attention and an incredible interest in the field of nanotechnology and biomedical science, which is merely due to their considerable and exclusive attributes; including their enhanced electron transferability, photobleaching and photo-blinking effects, high photoluminescent quantum yield, fluorescence property, resistance to photo-decomposition, increased electrocatalytic activity, good aqueous solubility, excellent biocompatibility, long-term chemical stability, cost-effectiveness, negligible toxicity, and acquaintance of large effective surface area-to-volume ratio. CDs can be readily functionalized owing to the abundant functional groups on their surfaces, and they also exhibit remarkable sensing features such as specific, selective, and multiplex detectability. In addition, the physico-chemical characteristics of CDs can be easily tunable based on their intended usage or application. In this comprehensive review article, we mainly discuss the classification of CDs, their ideal properties, their general synthesis approaches, and primary characterization techniques. More importantly, we update the readers about the recent trends of CDs in health care applications (viz., their substantial and prominent role in the area of electrochemical and optical biosensing, bioimaging, drug/gene delivery, as well as in photodynamic/photothermal therapy).

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Yuan, Ju Long, Fei Yan Lou, Zhao Zhong Zhou, Zhi Wei Wang y Bing Hai Lv. "Visualized Characterization of Slurry during CMP Based on LIF". Key Engineering Materials 315-316 (julio de 2006): 279–83. http://dx.doi.org/10.4028/www.scientific.net/kem.315-316.279.

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Chemical mechanical polishing has emerged recently as an indispensable processing technique in large scale integration. In chemical and mechanical polishing process, chemical and mechanical principle is the vital factor in the removal process. Little is known about what is occurring beneath a wafer during Chemical Mechanical Polishing (CMP) processes. The paper provides a LIF technology to visualize the fluid flow between the wafer and pad. In this paper, the experiment setup is built. And then, the images of fluorescence intensity excited by LIF have been obtained from CCD. Finally, the relationships between pH, temperature, laser power, film thickness and fluorescence intensity excited by LIF (Laser induced Fluorescence) are studied.

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Noun, Farah, Evelyne Anastasia Jury y Rafik Naccache. "Elucidating the Quenching Mechanism in Carbon Dot-Metal Interactions–Designing Sensitive and Selective Optical Probes". Sensors 21, n.º 4 (17 de febrero de 2021): 1391. http://dx.doi.org/10.3390/s21041391.

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Overexposure to metals has significant adverse effects on human and animal health coupled with nefarious consequences to the environment. Sensitive tools to measure low contaminant levels exist, but often come at a high cost and require tedious procedures. Thus, there exists a need for the development of affordable metal sensors that can offer high sensitivity and selectivity while being accessible on a global scale. Here, carbon dots, prepared in a one-pot synthesis using glutathione and formamide, have been developed as dual fluorescent metal sensing probes. Following extensive characterization of their physico-chemical properties, it is demonstrated that dual fluorescence can be exploited to build a robust ratiometric sensor with low-ppb detection sensitivity in water. This investigation shows that these optical probes are selective for Pb2+ and Hg2+ ions. Using steady-state and dynamic optical characterization techniques, coupled with hard and soft acid-base theory, the underlying reason for this selective behavior was identified. These findings shed light on the nature of metal-carbon dot interactions, which can be used to tailor their properties to target specific metal ions. Finally, these findings can be applicable to other fluorescent nanoparticle systems that are targeted for development as metal sensors.

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Khan, MAA, MS Saha, S. Sultana y AN Ahmed. "Preparation and Characterization of White Carbon Black From Rice Husk". Journal of Environmental Science and Natural Resources 9, n.º 2 (14 de abril de 2017): 1–7. http://dx.doi.org/10.3329/jesnr.v9i2.32135.

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Generally white carbon black in a form of silica is used instead of carbon black as reinforcing filler for rubber compounding. In the present research white carbon black was prepared from rice husks in cost effective method with direct incineration of acid leaching rice husk. The physico-chemical properties of rice husk and the product of white carbon black obtained from rice husk were investigated by Thermogravimetry, Particle size analyzer, Scanning electron microscope; Fourier transformed infrared radiation (FTIR), X-ray fluorescence and X-ray difractometry analyses. It was found that the decomposition of organic constituents of rice husk was revealed by Thermo gravimetric and carbon, hydrogen, nitrogen, sulpher (CHNS) analyses. The FTIR spectrum showed presence of Si-O-Si band with a strong peak at 1085 cm-1. The analysis of particle size and scanning electron microscope demonstrated that the produced white carbon black represent different size of 112 ?m to 0.01 ?m with very small nano-particle and amorphous structure. The amorphous structure of product was also confirmed by XRD pattern. The high pure product as 99.9% was confirmed by XRF analysis. These types of product have potential application as filler in rubber compounding.J. Environ. Sci. & Natural Resources, 9(2): 1-7 2016

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Šuňovská, Anna, Miroslav Horník, Martin Pipíška, Juraj Lesný, Jozef Augustín y Stanislav Hostin. "CHARACTERIZATION OF SOIL ADDITIVE DERIVED FROM SEWAGE SLUDGE". Nova Biotechnologica et Chimica 12, n.º 2 (1 de diciembre de 2013): 141–53. http://dx.doi.org/10.2478/nbec-2013-0016.

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Abstract The aim of the present work is to characterize the soil additive derived from sewage sludge as potentially economically acceptable material for agricultural production as well as for soil and environment protection. The soil additive consisting of sewage sludge obtained from the wastewater treatment plant Pannon-Víz Zrt. (Győr, Hungary) and agricultural byproducts represented by wastes from grain mill industry and crushed corn cobs was prepared using the low-capacity granulator equipment constructed by Energy Agency Public Nonprofit Ltd. (Hungary). The characterization of sewage sludge as primary composite and prepared soil additive includes the determination of physico-chemical parameters such as pH determined in suspension with distilled water, 0.01 mol/dm3 CaCl2 or 1 mol/dm3 KCl solutions, pHzpc predicted by potentiometric titration and ProtoFit software, water holding capacity (WHC), cationexchange capacity (CEC) and total organic carbon (TOC). The elemental analysis by X-ray fluorescence spectrometry revealed that sewage sludge as well as prepared soil additive contain significant amount of Zn and Cu as important microelements in plant nutrition. Also, it was found that prepared soil additive represents the considerable source of a significant proportion, strong bound and in this way gradually released microelements. Obtained results suggest on the application potential of prepared soil additive in agricultural production as well as in remediation and reclamation of contaminated or degraded soil.

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Martin, Georgianna L., Justin A. Ross, Shelley D. Minteer, David M. Jameson y Michael J. Cooney. "Fluorescence characterization of chemical microenvironments in hydrophobically modified chitosan". Carbohydrate Polymers 77, n.º 4 (19 de julio de 2009): 695–702. http://dx.doi.org/10.1016/j.carbpol.2009.02.021.

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Sakurai, Kenji y Atsuo lida. "Near-Surface Chemical Characterization Using Grazing Incidence X-ray Fluorescence". Advances in X-ray Analysis 33 (1989): 205–11. http://dx.doi.org/10.1154/s0376030800019601.

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External X-ray total reflection occurs when collimated X-ray beams impinge on a smooth, flat surface of matter at a small glancing angle, typically a few mrad. With respect to the X-ray fluorescence technique, total reflection experiments have allowed the trace determination of solution samples using an X-ray mirror as a sample support. The grazing incidence X-ray fluorescence technique (GIF) is also suitable for near-surface element analysis of the material, because the penetration depth of X-rays is 10-1000 Å around the critical angle.

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23

Mesrar, Laila, Mariam Akdim, Mohamed Lakrim, Omar El Aroussi, Iatimad Akhrif y Raouf Jabrane. "The Physico-Mechanical Characteristics of the Clays in and After Doping With Metal Oxide Al2O3 in the Region of Fez (Morocco)". Present Environment and Sustainable Development 9, n.º 1 (1 de mayo de 2015): 103–10. http://dx.doi.org/10.1515/pesd-2015-0006.

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Abstract Miocene marl is one of the widespread geological substrates in Fez vicinity (Central Morocco). In this study we proceed by a physicochemical characterization of the marl after doping with metal oxides, by various analytical techniques, namely the X-ray fluorescence, the mineralogical analysis, and dielectric property. The doping of these marl was conducted by solid oxides of Al2O3 at different percentages (5%, 10% and 15%). The results of chemical analysis showed the Al2O3 increase during doping. So, the mineralogical analysis of doped clays shows peaks' increases for kaolin. The marl doped acquired the property of their good electrical conductor compared to crass marl.

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Havrilla, George J. y Thomasin Miller. "Micro X-ray fluorescence in materials characterization". Powder Diffraction 19, n.º 2 (junio de 2004): 119–26. http://dx.doi.org/10.1154/1.1752947.

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Micro X-ray fluorescence (MXRF) offers the analyst a new approach to materials characterization. The range of applications is expanding rapidly. Single point analysis has been demonstrated for nanoliter volumes with detection limits at the 0.5 ng level. MXRF can be used as an element specific detector for capillary electrophoresis. Elemental imaging applications include analysis of sample corrosion and polymers, use as a combinatorial chemistry screening tool, and integration with molecular spectroscopic imaging methods to provide a more comprehensive characterization. Three-dimensional elemental imaging is a reality with the development of a confocal X-ray fluorescence microscope. Stereoview elemental X-ray imaging can provide unique views of materials that flat two-dimensional images cannot achieve. Spectral imaging offers chemical imaging capability, moving MXRF into a higher level of information content. The future is bright for MXRF as a materials characterization tool.

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Hadfi, Abdallah, Said Ben Aazza, M'barek Belattar, Said Mohareb y Ali Driouiche. "Study of the physico-chemical quality of the water of irrigation in Biougra circle along with highlighting the effectiveness of an inhibitor of calcium carbonate precipitation". Mediterranean Journal of Chemistry 7, n.º 4 (21 de noviembre de 2018): 272–85. http://dx.doi.org/10.13171/mjc74181121-hadfi.

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Localized irrigation is characterized by localized frequent and continuous water supply. It ensures the efficient use of water. However, this fertigation system suffers from the problem of clogging of the distributors. The present study aims to study the physico-chemical quality of the water of irrigation within the Biougra circle; analyze of the type of scale deposited in the water pipes and the highlight of the effectiveness of an inhibitor of calcium carbonate precipitation. This study was carried out at a temperature of 25°C, using the technical "LCGE". Indeed, the classification of irrigation water, according to Piper, revealed that the analyzed waters are characterized by calcium and magnesium bicarbonate facies with a slight tendency to migrate to the calcium and magnesium chloride and sulfate facies. The characterization of the scale collected in the irrigation water pipes of Biougra circle by X-ray fluorescence, X-ray diffraction and thermal analysis (ATD-ATG) made it possible to prove that the scale is mainly formed of calcium carbonate with calcite variety. The inhibition of calcium carbonate precipitation by a food inhibitor was obtained with a concentration of 0.6 mg/L.

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Rabilou Souley Moussa, Ousmaila Sanda Mamane, Issa Habou, Maman Mousbahou Malam Alma y Ibrahim Natatou. "Textural, mineralogical and physico-chemical characterization of red clay of Tanout (Zinder-Niger) with a view to its valorization in water treatment". GSC Advanced Research and Reviews 13, n.º 3 (30 de diciembre de 2022): 039–53. http://dx.doi.org/10.30574/gscarr.2022.13.3.0339.

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This study aims to determine the textural (specific surface, pore volume and pore size) and mineralogical characteristics of Tanout red clay of Zinder region (Niger) in order to have textural data allowing its use as an adsorbent. The methodology is based on textural analyzes (adsorption of N2 at 77 K by the Brunauer-Emmett-Teller method), mineralogical (X-ray fluorescence, X-ray diffraction, thermo-gravimetric analysis, scanning electron microscopy) and physicochemical (preliminary analyses). The results obtained show that the red clay has a specific surface of 418.4 m2.g-1 and 967.7 m2.g-1 calculated according to the BET and Langmuir methods respectively and a microporous surface of 540 m2.g- 1, with pore volume varying from 0.0389 to 0.2535 cm3.g-1 and pore size varying from 0.3675 to 5.423 nm calculated according to the methods (Barrett-Joyner-Halenda, Dubinin-Radushkevich, Dubinin -A, Horvath-Kawazoe and Saito-Foley). It has slit and cylindrical micro- pores. It has a slightly neutral pH in an aqueous medium and a high cation exchange capacity with low humidity and density, and is mainly composed of SiO2 (83.2%), Al2O3 (7.04%) and Fe2O3 (3.35%) with trace elements, the main ones being: Zr (2490 ppm), Sr (310.21 ppm), Cu (310.1 ppm), V (290.1 ppm) and Zn (140ppm). It consists essentially of Montmorillonite, illite and Kaolinite with impurities such as quartz and rutile. This clay has a high degree of crystallinity. These characteristics make it a promoter material that can be used as an adsorbent.

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Boutarfa, Fares, Abdelaziz Idres, Zohir Mekti, Radouane Graine, Fahem Tiour, Nadiia Dovbash, Aissa Benselhoub y Stefano Bellucci. "Airborne dust pollution emitted by El Hadjar Metallurgical Complex: quantification, characterization, and occupational health hazards". Technology audit and production reserves 5, n.º 3(73) (23 de octubre de 2023): 20–28. http://dx.doi.org/10.15587/2706-5448.2023.289353.

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The iron deposits of Ouenza and Boukhadra represent one of the main sources of iron ore supply for the Algerian steel industry. Being a fundamental wealth available to Algeria, the exploitation of iron ores and its use causes strong negative consequences on the environment, mainly by the expansion of dust, which will be a source of environmental degradation. The metallurgical industry is an integral part of the Algerian economy. Environmental problems that negatively affect the health of people and the environment is air pollution. These issues are relevant to the site and the town of Annaba, where the metallurgical industry is developed. Environmental awareness is characterized by strong environmental sensitization; especially in urban areas with metallurgical pollution sources. The object of this study is taking samples from sites that generate more dust within the steel complex plant. This study aims to characterize steelmaking dust from different sites of the plant in order to identify the mineral phases and their chemical compositions. The various analytical methods used include physico-chemical analysis, X-ray fluorescence (XRF), crystal phases, crystal size, lattice parameters, microdeformations, laser granulometry analysis, X-ray diffraction, microscopy Electronic Scanning and Analysis (EDS) Energy Dispersion Spectroscopy. It was found that the average monthly quantity of dust released by the dust collectors of the Agglomerated Material Preparation (AMP) unit is 108.45 tons. The results obtained from the dust samples analysis of dust samples from the different points of the site differ in their mineral and chemical composition. The research confirmed the presence of iron oxides, silicon, many different mineral phases. The results of dimensional analysis prove that the two samples are different in their sizes ESP1et and ESP2 is coarser than ESP3 and FF3A, these results can lead to long-term occupational illnesses.

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Pouroutzidou, Georgia K., Liliana Liverani, Anna Theocharidou, Ioannis Tsamesidis, Maria Lazaridou, Evi Christodoulou, Anastasia Beketova et al. "Synthesis and Characterization of Mesoporous Mg- and Sr-Doped Nanoparticles for Moxifloxacin Drug Delivery in Promising Tissue Engineering Applications". International Journal of Molecular Sciences 22, n.º 2 (8 de enero de 2021): 577. http://dx.doi.org/10.3390/ijms22020577.

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Mesoporous silica-based nanoparticles (MSNs) are considered promising drug carriers because of their ordered pore structure, which permits high drug loading and release capacity. The dissolution of Si and Ca from MSNs can trigger osteogenic differentiation of stem cells towards extracellular matrix calcification, while Mg and Sr constitute key elements of bone biology and metabolism. The aim of this study was the synthesis and characterization of sol–gel-derived MSNs co-doped with Ca, Mg and Sr. Their physico-chemical properties were investigated by X-ray diffraction (XRD), scanning electron microscopy with energy dispersive X-ray analysis (SEM/EDX), transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FTIR), X-ray fluorescence spectroscopy (XRF), Brunauer Emmett Teller and Brunauer Joyner Halenda (BET/BJH), dynamic light scattering (DLS) and ζ-potential measurements. Moxifloxacin loading and release profiles were assessed with high performance liquid chromatography (HPLC) cell viability on human periodontal ligament fibroblasts and their hemolytic activity in contact with human red blood cells (RBCs) at various concentrations were also investigated. Doped MSNs generally retained their textural characteristics, while different compositions affected particle size, hemolytic activity and moxifloxacin loading/release profiles. All co-doped MSNs revealed the formation of hydroxycarbonate apatite on their surface after immersion in simulated body fluid (SBF) and promoted mitochondrial activity and cell proliferation.

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Pouroutzidou, Georgia K., Liliana Liverani, Anna Theocharidou, Ioannis Tsamesidis, Maria Lazaridou, Evi Christodoulou, Anastasia Beketova et al. "Synthesis and Characterization of Mesoporous Mg- and Sr-Doped Nanoparticles for Moxifloxacin Drug Delivery in Promising Tissue Engineering Applications". International Journal of Molecular Sciences 22, n.º 2 (8 de enero de 2021): 577. http://dx.doi.org/10.3390/ijms22020577.

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Mesoporous silica-based nanoparticles (MSNs) are considered promising drug carriers because of their ordered pore structure, which permits high drug loading and release capacity. The dissolution of Si and Ca from MSNs can trigger osteogenic differentiation of stem cells towards extracellular matrix calcification, while Mg and Sr constitute key elements of bone biology and metabolism. The aim of this study was the synthesis and characterization of sol–gel-derived MSNs co-doped with Ca, Mg and Sr. Their physico-chemical properties were investigated by X-ray diffraction (XRD), scanning electron microscopy with energy dispersive X-ray analysis (SEM/EDX), transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FTIR), X-ray fluorescence spectroscopy (XRF), Brunauer Emmett Teller and Brunauer Joyner Halenda (BET/BJH), dynamic light scattering (DLS) and ζ-potential measurements. Moxifloxacin loading and release profiles were assessed with high performance liquid chromatography (HPLC) cell viability on human periodontal ligament fibroblasts and their hemolytic activity in contact with human red blood cells (RBCs) at various concentrations were also investigated. Doped MSNs generally retained their textural characteristics, while different compositions affected particle size, hemolytic activity and moxifloxacin loading/release profiles. All co-doped MSNs revealed the formation of hydroxycarbonate apatite on their surface after immersion in simulated body fluid (SBF) and promoted mitochondrial activity and cell proliferation.

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Konale, Ram Ashok, Nilesh Keshavrao Mahale y Sopan Tukaram Ingle. "Nano-zeolite-graphene oxide composite for calcium hardness removal: isotherm and kinetic study". Water Practice and Technology 15, n.º 4 (25 de agosto de 2020): 1011–31. http://dx.doi.org/10.2166/wpt.2020.079.

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Abstract The present study is an attempt to synthesize and explore the applications of the synthetic nano-zeolites (nZ) and its composites with graphene oxide (GO) for water purification. The modified Hummer's method and hydrothermal methods were applied for the synthesis of the graphene oxide and nano zeolites respectively, followed by the preparation of the composite with the ultrasonic method. Scanning electron microscopy, energy dispersive analysis of X-rays, Fourier transform infrared spectroscopy and X-ray fluorescence were used for physico-chemical characterization of the composite. The various parameters of adsorbent dose, contact time, initial and final pH of solution were optimized for the removal of calcium hardness. The results indicate optimum removal (98%) can be reached at pH 7 while the removal is highly adsorbent dose-dependent. The nZGO removal data were investigated by pseudo-first-order, pseudo-second-order, Elovich, and intraparticle diffusion. In that, pseudo-second-order and intraparticle diffusion models are best fitted to the experimental data. The experimental data were also analysed by Langmuir, Freundlich and Temkin isotherms, the experimental data follows the Langmuir isotherm and the determination coefficient is 0.99.

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Dorozhkin, P., E. Kuznetsov, A. Schokin, S. Timofeev y V. Bykov. "AFM + Raman Microscopy + SNOM + Tip-Enhanced Raman: Instrumentation and Applications". Microscopy Today 18, n.º 6 (noviembre de 2010): 28–32. http://dx.doi.org/10.1017/s1551929510000982.

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Atomic Force Microscopy (AFM) has developed into a very powerful tool for characterization of surfaces and nanoscale objects. Many physical properties of an object can be studied by AFM with nanometer-scale resolution. Local stiffness, elasticity, conductivity, capacitance, magnetization, surface potential and work function, friction, piezo response—these and many other physical properties can be studied with over 30 AFM modes. What is typically lacking in information provided by AFM studies is the chemical composition of the sample and information about its crystal structure. To obtain this information other characterization techniques are required, such as Raman and fluorescence microscopy. The Raman effect (inelastic light scattering) provides extensive information about sample chemical composition, quality of crystal structure, crystal orientation, presence of impurities and defects, and so on. Information provided by Raman and fluorescence spectroscopy is complementary to the information obtained by AFM. So it is a natural requirement in many research fields to integrate these techniques in one piece of equipment—to provide comprehensive physical, chemical, and structural characterization of the same object. Of course, for routine studies of various samples, it is important to be able to obtain AFM and Raman/fluorescence images of exactly the same sample area, preferably with the same sample scan.

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Gouisset, E., G. Rioland, F. Bourcier, D. Faye, P. Walter y F. Infante. "Detection and characterization of contamination with fluorescence spectroscopy". IOP Conference Series: Materials Science and Engineering 1287, n.º 1 (1 de agosto de 2023): 012025. http://dx.doi.org/10.1088/1757-899x/1287/1/012025.

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Abstract In the field of failure analysis and in particular molecular and particulate contamination, being able to detect any trace of contaminants during the integration of an orbital spacecraft is crucial. In this context, fluorescence allows not only to detect but also to discriminate contaminants. We studied the fluorescence response of two epoxy adhesives, typical sources of spacecraft contamination in orbit with a portable broadband hyperspectral instrument (UV-Vis-NIR) developed in collaboration with the CNES and Intraspec Technologies, but also with a commercial spectrofluorometer. These measurements had two objectives, evaluate the performance of our hyperspectral instrument in order to identify prospect of improvement, but as well study the pertinence of fluorescence signature study in the contamination field. The first goal brings out that the hyperspectral instrument is capable of imaging the scene and allows us to extract fluorescence spectra from the image, but it still needs development, especially in term of sensitivity in UV range. The second goal shows promising results. Fluorescence studies with the spectrofluorometer emphasize that fluorescence spectra are specific to the chemical nature of the contaminant, which allows us to clearly discriminate them.

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Laucks, M. L. y E. J. Davis. "Chemical characterization of single pollen particles via fluorescence and Raman spectroscopy". Journal of Aerosol Science 29 (septiembre de 1998): S603—S604. http://dx.doi.org/10.1016/s0021-8502(98)00423-6.

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Chotirach, Maslin, Supawan Tantayanon, Duangamol Nuntasri Tungasmita, Junliang Sun y Sukkaneste Tungasmita. "Synthesis and characterizations of TiN–SBA-15 mesoporous materials for CO2 dry reforming enhancement". Pure and Applied Chemistry 92, n.º 4 (28 de abril de 2020): 545–56. http://dx.doi.org/10.1515/pac-2019-0806.

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AbstractA novel approach of titanium nitride (TiN) incorporated into SBA-15 framework was developed using one-step hydrothermal synthesis method. TiN contents up to ~18 wt% were directly dispersed in a synthetic gel under a typical strong acidic condition. The physico-chemical characteristics and the surface properties were investigated by means of X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Fourier transform infrared spectroscopy (FTIR), N2 adsorption-desorption, field emission scanning electron microscope (FESEM) equipped with energy dispersive X-ray spectroscopy (EDS), wavelength dispersive X-ray fluorescence (WDXRF) and CO2-temperature programmed desorption (CO2-TPD). The results indicated that the highly ordered mesostructured was effectively maintained with high specific surface area of 532–685 m2g−1. The basicity of the modified SBA-15 increased with rising TiN loading. These modified materials were applied as a support of Ni catalyst in dry reforming of methane (DRM). Their catalytic behavior possessed superior conversions for both CO2 and CH4 with the highest H2/CO ratio (0.83) as well as 50 % lower carbon formation, compared to bare SBA-15 support.

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Paul, Paola, Essia Belhaj, Cécile Diliberto, Komla Lolonyo Apedo y Françoise Feugeas. "Comprehensive Characterization of Spent Chemical Foundry Sand for Use in Concrete". Sustainability 13, n.º 22 (21 de noviembre de 2021): 12881. http://dx.doi.org/10.3390/su132212881.

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The foundry industry generates large amounts of spent foundry sands, which are stored, available for recovery in other industrial sectors but unfortunately poorly exploited. Different authors have studied the possibility of recovering them in concretes, which would also allow production of more sustainable cementitious materials. The variability of their results highlights the importance of a better understanding of the potential influential parameters of the by-products. Unfortunately, exhaustive characterizations of the materials are rarely performed, especially for chemically bound foundry sands. This article presents a case study for the recovery of a spent chemical foundry sand with an exhaustive physicochemical characterization of the by-product and an analysis of its influence on the workability and mechanical strengths of cementitious materials. The tests recommended by the European standard for aggregates for concrete confirmed the suitability of the by-product. Associated with additional chemical tests (scanning electron microscopy, X-ray fluorescence, X-ray diffraction, etc.) as well as metallic particles characterization, they highlighted possible influential parameters. The workability and mechanical resistance tests carried out on mortars and concretes confirmed the influence of the fineness of the by-product associated with other parameters. Its use at a substitution rate of 30% results in a strength class C 30/37 concrete.

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Itoua, Prince Igor, Daquan Sun, Ping Li y Shihui Shen. "Influence of Waste Toner on Asphalt Binder: Chemical and Rheological Characterization". Molecules 28, n.º 6 (20 de marzo de 2023): 2794. http://dx.doi.org/10.3390/molecules28062794.

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The growing amount of waste toner (WT) has posed a significant environmental challenge. Meanwhile, researchers are interested in the feasibility of utilizing waste toner as an asphalt binder modifier because its primary chemical components (Styrene-acrylic copolymer and carbon black) are known to improve asphalt properties. The objective of this study was to evaluate the chemical and rheological properties of the waste-toner-modified asphalt binder and hence determine the suitability of integrating waste toner for asphalt modification. The waste-toner-modified asphalt (TMA) binders were produced by blending base asphalt with two types of waste toners of different gradation sizes. Microscopic tests such as x-ray fluorescence (XRF), attenuated total reflectance transform infrared spectroscopy (ATR-FTIR), and scanning electron microscopy with energy dispersive X-ray (SEM-EDS) and fluorescence microscope, as well as rheology tests such as multiple stress creep recovery (MSCR) tests, oscillation tests, and bending beam rheometer tests were performed. The FTIR results showed that there was a chemical reaction between waste toners and base asphalt binder. A fluorescence effect was observed on the binders produced with different toners used in this research. The binder modified with an optimal content of 8%WTs revealed better high and low-temperature properties. Additionally, 8%WTs used in this research could change the PG70-22 binder to PG76-22 binder. The rutting properties of asphalt material were improved for its improved elasticity. In addition, the 200-mesh TMA binders were desirable with respect to waste toner particle size. Overall, there is a benefit to using waste toner in the asphalt industry.

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Mesboua, N., K. Benyounes, S. Kennouche, Y. Ammar, A. Benmounah y H. Kemer. "Calcinated Bentonite as Supplementary Cementitious Materials in Cement-Based Mortar". Journal of Applied Engineering Sciences 11, n.º 1 (1 de mayo de 2021): 23–32. http://dx.doi.org/10.2478/jaes-2021-0004.

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Abstract The construction industry consumes a large quantity of cement, which therefore leads to a high CO2 emission due to the cement manufacture. The partial replacement of cement by supplementary cementations materials (SCMs) is considered as the most promising alternative to reduce the environmental impact of this industry. This investigation aims to evaluate the performance of calcinated clay (calcined bentonite at 850 °C) used as partial replacement of cement in cement-based mortar. The evaluated performances include the physico-chemical and mechanical properties, as well as microstructural characteristics.. Various characterization tests, including laser granulometry, X-ray diffraction (XRD), and X-ray fluorescence spectrometry (XRF) have been investigated. In addition, the hardened properties of different mortar mixtures were also investigated. Mortar mixtures incorporating different calcinated clay percentages corresponding to 8, 10, 12, and 14%, by mass of total binder content, were proportioned. Termogravimetric analysis (TGA) and its derivative (DTG), Differential scanning calorimetry (DSC), and microstructural (Scanning electron microscopy (SEM)) analysis were carried out on samples of mortar mixtures. Furthermore, the 28-d hardened properties were assessed to assess the pozzolanic activity of the investigated mixtures. Strength activity index (SAI), DSC, and TGA analyzes are presented. The obtained results showed that all the mixtures exhibited adequate pozzolanic activity conforming to the ASTM C618 specifications.

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Colegial-Gutiérrez, Juan Diego, María Camila Forero-Quintero, María Alejandra Fuentes-Rueda y Sully Gomez Isidro. "Characterization of weathering profiles of the crystal rocks of eastern Bucaramanga and definition of hydrogeological properties". Boletín de Ciencias de la Tierra, n.º 41 (1 de enero de 2017): 16–30. http://dx.doi.org/10.15446/rbct.n41.59347.

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In the process of improving the knowledge of the hydrogeological potential of weathered zones in crystalline rocks and compounds that can behave as aquifers, this article is performed whose area of study is located east of the metropolitan area of Bucaramanga, Santander Massif consists of two main lithological units; the Neis of Bucaramanga and Santander Group plutonic (diorite, granodiorite-tonalite gray quartz monzonite and monzogranite). These rocks have undergone brittle deformation, physico-chemical weathering mainly influenced by the tropical atmosphere of the area also are jointed and fractured creating conditions that facilitate the flow of water and in turn be optimized weathering processes in the region. He appealed to the identification and location of field weathering profiles made a detailed study of outcrops, presenting a thickness of 90.4 m for the profile of the Gneisic rock weathering and 68.5 m for the profile of granodiorite rock, made up 6 steps weathering of which samples each were taken and carry out macroscopic analysis, petrographic and geochemical using thin films, determining the percentage of porosity, humidity, dry unit weight, X-ray fluorescence, electron microscopy Sweeping and Grading; base characterizing weathering profiles and properties, highlighting the potential hydrogeological found in the Range II: Slightly weathered rock and interval V: Completely weathered rock profile of granodiorite rock and Rock Gneisic profile, the interval III : Moderately weathered rock and the range V: Completely weathered rock, since these stages of weathering, moisture peaks present, regular micro fractures and high porosities.

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Abbaker, Ahmed Mohammedelmubarak, Eltahir Mohamed Moslim y Montasir Sabbah El Din Elsalmawy. "Mineralogical and Chemical Characterization of Bajrawia Iron Ore, Sudan". FES Journal of Engineering Sciences 8, n.º 1 (28 de marzo de 2019): 8–14. http://dx.doi.org/10.52981/fjes.v8i1.3.

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In this contribution, the mineralogical and chemical characterization of Bajrawia iron ore is investigated. The chemical analysis was conducted using atomic absorption spectroscopy, X-ray Fluorescence, Energy Dispersive X-ray and titration. The mineralogical characterization was obtained by optical microscopy and X-ray diffraction. The physical properties such as densities, water content and porosity were determined. It was found that Bajrawia iron ore contains about 35.5% Fe and some impurities like phosphorus and silica. Goethite is the major iron mineral associated with minor contents of hematite, kaolinite and quartz. SEM photo showed that the main minerals are goethite, clay minerals and quartz. The ore has low density because it has high porosity degree. This type of iron ore is disseminated in rock matrix and would be difficult to process.

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Sakurai, Kenji, Atsuo Iida y Yohichi Gohshi. "Chemical State Analysis by X-Ray Fluorescence Using Absorption Edges Shifts". Advances in X-ray Analysis 32 (1988): 167–76. http://dx.doi.org/10.1154/s0376030800020437.

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Recently synchrotron radiation (SR) sources have been extensively used for the study of materials science. The high intensity of tunable monochromatic X-rays from SR facilitates many types of spectroscopic/ diffraction studies which have otherwise not been possible. Regarding the X-ray fluorescence technique, significant improvement of the minimum detection limit has been performed and has enabled trace element analysis in the order of tens of ppb or 10-12 g.3-8 SR microanalyzers and near surface analysis using grazing incidence geometry are also attractive applications of synchrotron X-ray fluorescence technique. From a point of materials characterization, chemical state analysis is not less important than ordinary element analysis.

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Vallet, Sylvain D., Martin N. Davis, Anna Barqué, Ali H. Thahab, Sylvie Ricard-Blum y Alexandra Naba. "Computational and experimental characterization of the novel ECM glycoprotein SNED1 and prediction of its interactome". Biochemical Journal 478, n.º 7 (16 de abril de 2021): 1413–34. http://dx.doi.org/10.1042/bcj20200675.

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The extracellular matrix (ECM) is a complex meshwork of proteins and an essential component of multicellular life. We have recently reported the characterization of a novel ECM protein, SNED1, and showed that it promotes breast cancer metastasis and regulates craniofacial development. However, the mechanisms by which it does so remain unknown. ECM proteins exert their functions by binding to cell surface receptors and interacting with other ECM proteins, actions that we can predict using knowledge of protein's sequence, structure, and post-translational modifications. Here, we combined in-silico and in-vitro approaches to characterize the physico-chemical properties of SNED1 and infer its putative functions. To do so, we established a mammalian cell system to produce and purify SNED1 and its N-terminal fragment, which contains a NIDO domain, and demonstrated experimentally SNED1's potential to be glycosylated, phosphorylated, and incorporated into an insoluble ECM. We also determined the secondary and tertiary structures of SNED1 and its N-terminal fragment and obtained a model for its NIDO domain. Using computational predictions, we identified 114 proteins as putative SNED1 interactors, including the ECM protein fibronectin. Pathway analysis of the predicted SNED1 interactome further revealed that it may contribute to signaling through cell surface receptors, such as integrins, and participate in the regulation of ECM organization and developmental processes. Last, using fluorescence microscopy, we showed that SNED1 forms microfibrils within the ECM and partially colocalizes with fibronectin. Altogether, we provide a wealth of information on an understudied yet important ECM protein with the potential to decipher its pathophysiological functions.

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Cloin, Bas M. C., Elke De Zitter, Desiree Salas, Vincent Gielen, Gert E. Folkers, Marina Mikhaylova, Maike Bergeler et al. "Efficient switching of mCherry fluorescence using chemical caging". Proceedings of the National Academy of Sciences 114, n.º 27 (19 de junio de 2017): 7013–18. http://dx.doi.org/10.1073/pnas.1617280114.

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Fluorophores with dynamic or controllable fluorescence emission have become essential tools for advanced imaging, such as superresolution imaging. These applications have driven the continuing development of photoactivatable or photoconvertible labels, including genetically encoded fluorescent proteins. These new probes work well but require the introduction of new labels that may interfere with the proper functioning of existing constructs and therefore require extensive functional characterization. In this work we show that the widely used red fluorescent protein mCherry can be brought to a purely chemically induced blue-fluorescent state by incubation with β-mercaptoethanol (βME). The molecules can be recovered to the red fluorescent state by washing out the βME or through irradiation with violet light, with up to 80% total recovery. We show that this can be used to perform single-molecule localization microscopy (SMLM) on cells expressing mCherry, which renders this approach applicable to a very wide range of existing constructs. We performed a detailed investigation of the mechanism underlying these dynamics, using X-ray crystallography, NMR spectroscopy, and ab initio quantum-mechanical calculations. We find that the βME-induced fluorescence quenching of mCherry occurs both via the direct addition of βME to the chromophore and through βME-mediated reduction of the chromophore. These results not only offer a strategy to expand SMLM imaging to a broad range of available biological models, but also present unique insights into the chemistry and functioning of a highly important class of fluorophores.

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Wentrup-Byrne, E., L. Rintoul, J. L. Smith y P. M. Fredericks. "Comparison of Vibrational Spectroscopic Techniques for the Characterization of Human Gallstones". Applied Spectroscopy 49, n.º 7 (julio de 1995): 1028–36. http://dx.doi.org/10.1366/0003702953964813.

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A suite of human gallstones was investigated by vibrational spectroscopic techniques with a view to developing an effective characterization procedure. Using infrared microscopy, microspectroscopic mapping, infrared photoacoustic spectroscopy (PAS), and FT-Raman spectroscopy, we have examined both the chemical composition and the microstructure of the different categories of human gallstones. We show how infrared microscopy can be used to determine the chemical identity of particular microstructural features of a stone. Infrared mapping produces functional group maps of the surface of a gallstone and shows the actual distribution of the different chemical components. Good fluorescence-free FT-Raman spectra were obtained from all categories of stones except black stones, which gave a fluorescence background with no observable Raman spectrum. Of the vibrational techniques studied, PAS proved the most suited to the spectroscopic categorization of gallstones because data for the whole stone can be obtained with minimal sample preparation. The advantages and disadvantages of each technique are discussed.

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Kataoka, Y. y T. Arai. "Basic Studies of Multi-Layer Thin Film Analysis Using Fundamental Parameter Method". Advances in X-ray Analysis 33 (1989): 213–23. http://dx.doi.org/10.1154/s0376030800019613.

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X-ray fluorescence analysis is the most suitable method, for the characterization of the thickness and the chemical composition of thin film samples. It is non-destructive, rapid, precise, and accurate for both metal and oxide samples.

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Erich, M. Susan y Georgette M. Trusty. "Chemical characterization of dissolved organic matter released by limed and unlimed forest soil horizons". Canadian Journal of Soil Science 77, n.º 3 (1 de agosto de 1997): 405–13. http://dx.doi.org/10.4141/s96-024.

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Liming of forest soils, currently practiced in Europe, may be necessary in the future in North America to counteract calcium (Ca) depletion due to whole tree harvesting. With current concerns over increasing carbon dioxide (CO2) levels in the atmosphere, the effects of forest practices such as liming on carbon (C) cycling in forest ecosystems has been receiving increasing attention. This laboratory study investigated the effect of an increase in pH on dissolved organic matter (DOM) in water extracts of organic horizons. Organic horizons were collected from nine forested sites, some predominantly hardwood and some predominantly softwood stand types. The soils were chemically characterized. Water extracts of limed and unlimed treatments of nine organic horizons were analyzed for pH, Al, Fe, Ca, C, and DOM negative charge density. Total luminescence fluorescence spectra were also obtained for each extract. The addition of lime (CaCO3) to organic horizons caused an average of 55% more C to be released than in unamended samples. Liming caused no significant changes in negative charge density of the DOM. Liming decreased organically-complexed aluminum (Al) and increased organically-complexed Ca. There was a negative correlation between Al concentration of extracts and fluorescence intensity. Chemical changes in the DOM released by liming were suggested by decreased fluorescence emission and excitation wavelengths due to liming. Hardwood samples did not respond differently than softwood samples with respect to DOM concentration, functional group concentration, or spectroscopic characteristics. However, there was a suggestion that particular tree species, such as cedar, may have unique effects on C concentrations and DOM chemistry. Key words: Lime, forest soil, dissolved organic matter, fluorescence

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Caneppele, Taciana Marco Ferraz, Carlos Rocha Gomes Torres y Eduardo Bresciani. "Analysis of the Color and Fluorescence Alterations of Enamel and Dentin Treated With Hydrogen Peroxide". Brazilian Dental Journal 26, n.º 5 (octubre de 2015): 514–18. http://dx.doi.org/10.1590/0103-6440201300249.

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Abstract: The aim of this study was to evaluate the effect of hydrogen peroxide whitening on fluorescence and color of bovine enamel and dentin. Twenty five dentin discs and 25 enamel discs, with 6 mm diameter and 1 mm thick, were obtained. Direct fluorescence (spectrofluorophotometry) and color (spectrophotometry) were assessed. After fluorescence and color baseline measurements, specimens were immersed in a 35% hydrogen peroxide (HP) solution for 1 h. This procedure was repeated after 7 days. Final fluorescence and color measurements were performed after the second immersion. Chemical characterization of 5 additional specimens was also performed. Data were submitted to repeated analysis of variance and Tukey´s test for fluorescence and unpaired t-test for color and chemical components (p<0.05). Fluorescence decreased significantly in dentin specimens after whitening. Enamel presented lower fluorescence than dentin at baseline, but this parameter did not decrease after whitening. Color changes were observed for both substrates, with significantly greater whitening effect in dentin (ΔE=10.37) (p<0.001). Whitening by hydrogen peroxide induced significant decrease in fluorescence of tooth dentin and promoted significant color changes in dentin and enamel with more accentuated outcomes in dentin.

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Vieira, Yasmin, Mara Regina Linck, Delton Luiz Gobbi, Lucas Brandalise Menezes y Fernanda Da Silva Vilasbôas. "Influence of compression on soil characterization by X ray fluorescence". Semina Ciências Exatas e Tecnológicas 39, n.º 2 (29 de diciembre de 2018): 125. http://dx.doi.org/10.5433/1679-0375.2018v39n2p125.

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The study of soil mineralogy has been highlighted in recent years, as well as the search for alternative analytical techniques for soil analysis. The classical methods for determination of total oxides in soil expose the analyst to chemical hazards and require time-consuming sample preparation and decomposition. XRF is being employed for this type of analysis, since it does not requires the use of chemical solvents. However, the technique requires samples with a smooth and homogeneous surface. The objective of this study was to verify if the soil compression (in 5 t, 10 t and 15 t) influenced the determination of the oxides content in soils of different municipalities of the state of Rio Grande do Sul (Passo Fundo and Cruz Alta). The experiments and the analysis of the data showed that the XRF technique presented low coefficients of variation and low standard deviation and did not have statistical difference between the samples of the same type of soil. The lower variations of these analytical criteria were obtained for soil analysed in the form of powder. Therefore, the most suitable form for the analysis of these soils is in the sedimentary form, however, it is still recommended the use of statistical tools to verify the reliability of the data obtained.

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Mu, Taotao, Siying Chen, Yinchao Zhang, He Chen y Pan Guo. "Characterization of edible oils using time-resolved fluorescence". Anal. Methods 6, n.º 3 (2014): 940–43. http://dx.doi.org/10.1039/c3ay41552j.

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Ribeiro, Bruno Teixeira, Sérgio Henrique Godinho Silva, Elen Alvarenga Silva y Luiz Roberto Guimarães Guilherme. "Portable X-ray fluorescence (pXRF) applications in tropical Soil Science". Ciência e Agrotecnologia 41, n.º 3 (junio de 2017): 245–54. http://dx.doi.org/10.1590/1413-70542017413000117.

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ABSTRACT The X-ray fluorescence (XRF) is an analytical technique for determination of elemental composition of different materials. In soils, the XRF has many pedological, environmental and agronomic applications, mainly after the emergence of portable equipments (pXRF). This technique has been recently adopted and successfully used for soil characterization worldwide, but very rare works have been carried out in soils of developing countries. The soil characterization includes the complete elemental composition determination (nutrients, trace and rare-earth elements) and allows estimating some soil physical and chemical properties. In Brazil, this technique is still incipient, mainly the use of pXRF, however, it can greatly contribute to soil characterization in-field or in-lab conditions and also replacing methods of soil analyses considered non-environmentally friendly. This review summarizes the XRF technique including principles and the main applications of pXRF in soils highlighting its potential for tropical Soil Science.

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Li, Shan Shan, Fu Tian Liu, Qun Wang, Xiu Xiu Chen y Ping Yang. "Synthesis and Characterization of Water-Soluble Cu²⁺-Doped ZnSe Quantum Dots". Advanced Materials Research 79-82 (agosto de 2009): 2043–46. http://dx.doi.org/10.4028/www.scientific.net/amr.79-82.2043.

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Cu2+-doped ZnSe quantum dots (ZnSe:Cu) were prepared via a green and simple route, namely the chemical coprecipitation method. Under 365 nm UV excitation, green emission is observed. X-ray powder diffraction (XRD) shows that ZnSe:Cu nanoparticle is cubic zinc blende structure; the transmission electron microscopy (TEM) exhibits that the average diameter of ZnSe:Cu nanocrystals is less than 10 nm. UV-vis spectrophotometer and fluorescence spectrophotometer indicate that ZnSe:Cu nanocrystals have good fluorescence effects.

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