Articoli di riviste: "Phase quantification"

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Döbelin, Nicola. "Validation of XRD phase quantification using semi-synthetic data". Powder Diffraction 35, n. 4 (13 ottobre 2020): 262–75. http://dx.doi.org/10.1017/s0885715620000573.

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Validating phase quantification procedures of powder X-ray diffraction (XRD) data for an implementation in an ISO/IEC 17025 accredited environment has been challenging due to a general lack of suitable certified reference materials. The preparation of highly pure and crystalline reference materials and mixtures thereof may exceed the costs for a profitable and justifiable implementation. This study presents a method for the validation of XRD phase quantifications based on semi-synthetic datasets that reduces the effort for a full method validation drastically. Datasets of nearly pure reference substances are stripped of impurity signals and rescaled to 100% crystallinity, thus eliminating the need for the preparation of ultra-pure and -crystalline materials. The processed datasets are then combined numerically while preserving all sample- and instrument-characteristic features of the peak profile, thereby creating multi-phase diffraction patterns of precisely known composition. The number of compositions and repetitions is only limited by computational power and storage capacity. These datasets can be used as input files for the phase quantification procedure, in which statistical validation parameters such as precision, accuracy, linearity, and limits of detection and quantification can be determined from a statistically sound number of datasets and compositions.

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Takehara, L., M. A. Z. Vasconcellos, R. Hinrichs, J. B. M. da Cunha e F. Chemale Jr. "Phase quantification in iron ore". Mineral Processing and Extractive Metallurgy 118, n. 3 (settembre 2009): 168–74. http://dx.doi.org/10.1179/174328509x431445.

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Hall, Caitrín, Ji Chul Kim e Alexandra Paxton. "Multidimensional recurrence quantification analysis of human-metronome phasing". PLOS ONE 18, n. 2 (23 febbraio 2023): e0279987. http://dx.doi.org/10.1371/journal.pone.0279987.

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Perception-action coordination (also known as sensorimotor synchronization, SMS) is often studied by analyzing motor coordination with auditory rhythms. The current study assesses phasing—a compositional technique in which two people tap the same rhythm at varying phases by adjusting tempi—to explore how SMS is impacted by individual and situational factors. After practice trials, participants engaged in the experimental phasing task with a metronome at tempi ranging from 80–140 beats per minute (bpm). Multidimensional recurrence quantification analysis (MdRQA) was used to compare nonlinear dynamics of phasing performance. Varying coupling patterns emerged and were significantly predicted by tempo and linguistic experience. Participants who successfully phased replicated findings from an original case study, demonstrating stable tapping patterns near in-phase and antiphase, while those unsuccessful at phasing showed weaker attraction to in-phase and antiphase.

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Harnett, L., M. Stennett, E. Maddrell e N. Hyatt. "Characterisation of glass ceramic wasteforms using quantitative image analysis of electron micrographs". MRS Advances 7, n. 5-6 (9 febbraio 2022): 86–89. http://dx.doi.org/10.1557/s43580-022-00227-0.

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Abstract Multi-phase material systems make up a significant proportion of the currently proposed and researched wasteforms for sequestration of heterogeneous nuclear material feeds. Quantification of the components for such multi-phase assemblages is typically performed using diffraction-based Rietveld methods, many of which necessitate long measurement times of several hours. Furthermore, careful additions of an internal standard are typically required, to facilitate inclusion of amorphous phases in the quantification. The application of an image analysis method has been investigated, using the z-contrast greyscale of back-scattered electron micrographs to determine the relative quantities of component phases in a suite of monolithic phosphate glass ceramic wasteforms. This work demonstrates an alternate methodology for accelerated quantification which could be applied to other heterogeneous wasteforms and multi-phase materials. Graphical abstract

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Ergin, F. Gökhan. "Accuracy Improvement Quantification Using Phase-Separated PIV Measurements". Proceedings of the International Symposium on the Application of Laser and Imaging Techniques to Fluid Mechanics 21 (8 luglio 2024): 1–7. http://dx.doi.org/10.55037/lxlaser.21st.4.

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This paper aims to quantify the Particle Image Velocimetry (PIV) measurement accuracy improvement along the phase boundaries of two-phase flows, due to the use of phase-separated PIV analysis, compared to conventional PIV analysis without separating the phases. To compute the true error produced by PIV analysis, a patchwork of synthetic image pair with a known displacement is used (ground truth). As real flows might have arbitrary flow direction and magnitude across the phase boundary, the patchwork of image-pair includes a variety of direction combinations, i.e. flows running into each other or away from one another, shear flow, sink flow, flow towards a wall and flow away from a wall, flow running into a stagnant phase, flows with perpendicular directions, and flows that are 45° to each other. The relative error distribution along the boundaries reveals that the relative error level depends on the flow direction on each side of the boundary. Results also indicate that phase-separated PIV measurements can bring the relative error level from ~200% down to ~5% along the boundaries.

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Sheiati, Shohreh, Hoang Nguyen, Paivo Kinnunen e Navid Ranjbar. "Cementitious phase quantification using deep learning". Cement and Concrete Research 172 (ottobre 2023): 107231. http://dx.doi.org/10.1016/j.cemconres.2023.107231.

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Reddy, K. Chiranjeevi, e Kolluru V. L. Subramaniam. "Quantitative phase analysis of slag hydrating in an alkaline environment". Journal of Applied Crystallography 53, n. 2 (13 marzo 2020): 424–34. http://dx.doi.org/10.1107/s1600576720001399.

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An X-ray diffraction (XRD)-based evaluation of the crystalline and amorphous phases in slag hydrating in an alkaline environment is presented. A method is developed for the quantification of the amorphous phases present in hydrating slag in a sodium hydroxide solution. In hydrating slag, the amorphous reaction product is identified as calcium aluminosilicate hydrate. A water-soluble sodium-based amorphous reaction product is also produced. The XRD-based quantification method relies on the direct decomposition of the XRD intensity pattern of the total amorphous phase present in partially hydrated slag into the intensity patterns of the amorphous unreacted slag, the hydrate and the sodium-based product. The unreacted slag content in partially hydrated slag is also determined from the decomposition of the intensity signature of the total amorphous phase. An independent verification of the amorphous unreacted slag content in hydrating slag is obtained from measurements of blends of unhydrated and partially hydrated slag. The XRD-based phase-quantification procedure developed here provides a basis for evaluating the extent of reaction in hydrating slag.

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Hagni, Ann M. "Phase identification, phase quantification, and phase association determinations utilizing automated mineralogy technology". JOM 60, n. 4 (aprile 2008): 33–37. http://dx.doi.org/10.1007/s11837-008-0045-8.

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Wininger, Michael, Alex Krasner, Nam Hun Kim e William Craelius. "Phase plane quantification of single-joint smoothness". Journal of Biomedical Engineering and Informatics 4, n. 1 (15 maggio 2018): 40. http://dx.doi.org/10.5430/jbei.v4n1p40.

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We report a metric of single joint movement smoothness based on phase plane analysis of trajectories of the wrist about the elbow. Overall smoothness was quantified as the Phase Area Ratio (PAR), comparing the total area circumscribed by the acceleration-velocity (A-V) curve, to the area of its convex hull; PAR ranges from 0 (perfectly smooth) to 1 (gross motor impairment). Elbow flexion records obtained from a cohort study showed that PAR was significantly different in intact (PAR = 9.4x10-4 ± 6.6x10-4, group average, N = 18) versus chronic stroke patients (0.11 ± 0.15, N = 9; Wilcoxon rank-sum on group means: P < .0001). Separate simulations showed that PAR was appropriately insensitive to velocity asymmetry and to scale factors, e.g. range of motion, peak- and average velocity, and movement duration. We conclude that PAR is an attractive smoothness measure, as it accomplishes four objectives: 1) insensitivity to scale factors unrelated to trajectory shape, 2) discrimination of an intact versus impaired cohort, 3) reporting a near-zero impairment for healthy actors, responding appropriately to asymmetries commonly observed in human movement, and 4) operation on a fixed, closed scale.

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Ilbagi, A., H. Henein e A. B. Phillion. "Phase quantification of impulse atomized Al68.5Ni31.5 alloy". Journal of Materials Science 46, n. 19 (2 novembre 2010): 6235–42. http://dx.doi.org/10.1007/s10853-010-4972-8.

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Forero, Manuel G., Carlos A. Jacanamejoy, Maximiliano Machado e Karla L. Penagos. "Generalized Quantification Function of Monogenic Phase Congruency". Mathematics 11, n. 17 (4 settembre 2023): 3795. http://dx.doi.org/10.3390/math11173795.

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Edge detection is a technique in digital image processing that detects the contours of objects based on changes in brightness. Edges can be used to determine the size, orientation, and properties of the object of interest within an image. There are different techniques employed for edge detection, one of them being phase congruency, a recently developed but still relatively unknown technique due to its mathematical and computational complexity compared to more popular methods. Additionally, it requires the adjustment of a greater number of parameters than traditional techniques. Recently, a unique formulation was proposed for the mathematical description of phase congruency, leading to a better understanding of the technique. This formulation consists of three factors, including a quantification function, which, depending on its characteristics, allows for improved edge detection. However, a detailed study of the characteristics had not been conducted. Therefore, this article proposes the development of a generalized function for quantifying phase congruency, based on the family of functions that, according to a previous study, yielded the best results in edge detection.

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Sobanska, Anna W., e Jaroslaw Pyzowski. "Quantification of Sunscreen Ethylhexyl Triazone in Topical Skin-Care Products by Normal-Phase TLC/Densitometry". Scientific World Journal 2012 (2012): 1–6. http://dx.doi.org/10.1100/2012/807516.

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Ethylhexyl triazone (ET) was separated from other sunscreens such as avobenzone, octocrylene, octyl methoxycinnamate, and diethylamino hydroxybenzoyl hexyl benzoate and from parabens by normal-phase HPTLC on silica gel 60 as stationary phase. Two mobile phases were particularly effective: (A) cyclohexane-diethyl ether 1 : 1 (v/v) and (B) cyclohexane-diethyl ether-acetone 15 : 1 : 2 (v/v/v) since apart from ET analysis they facilitated separation and quantification of other sunscreens present in the formulations. Densitometric scanning was performed at 300 nm. Calibration curves for ET were nonlinear (second-degree polynomials), withR> 0.998. For both mobile phases limits of detection (LOD) were 0.03 and limits of quantification (LOQ) 0.1 μg spot−1. Both methods were validated.

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Benyahia, Anis, Soraya Tebbal, Bouthayna Chiboub, Mourad Sadelaoud, Hocine Bouncer, Amira Housna Ameghchouche e Assia Aouachria. "Interest of the quantification of HBsAg in the chronic carrier of the hepatitis B virus". Batna Journal of Medical Sciences (BJMS) 7, n. 2 (9 novembre 2020): 137–41. http://dx.doi.org/10.48087/bjmsoa.2020.7216.

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La quantification de l’AgHBs a montré un intérêt dans la classification du patient dans les différentes phases de l’infection chronique B. Pour évaluer l’impact de celle-ci, nous avons mené une étude prospective chez les porteurs chroniques du VHB, sur une période de 5 ans. Nous avons colligé 210 patients (114 hommes ; 96 femmes), avec un âge moyen de 43 ans (18 – 80 ans), une cytolyse dans 12% des cas (25/210) et 90% des patients AgHBe négatif (189/210). L’ADN-VHB moyen est de 3,25 ± 2 Log UI/ml. Une fibrose modérée à sévère (F2, F3, F4) est noté dans 21,42% (45/210). Le taux moyen de l’AgHBs est de 2,84 ± 1,1 Log UI/ml, il est de 4,36 LogUI/ml chez le sujet jeune versus 3 LogUI/ml pour le sujet âgé. Nous avons noté une corrélation entre le taux de l’AgHBs et celui de l’ADN VHB (r=0,40, p<0,001). Ce taux est plus élevé pour l’AgHBe positif (3,81 LogUI/ml vs 2,77 LogUI/ml). Les taux moyens d’AgHBs sont de 4,33 ; 3,13 ; 2,87 et 3,19 logUI/ml aux phases 1, 2, 3 et 4 respectivement. Entre phase 1 et phase 3, il est de 3,6 ± 1,5 vs 2,07 ± 1 (p< 0,001). Entre phase active (2 et 4) et phase inactive (3), il est de 3,35 ± 0,7 vs 2,07 ± 1 (p<0,00001). Pour un taux d’ADN VHB < 2000 UI/ml et d’AgHBs < 1000 UI/ml, la proportion de porteurs inactifs est de 43% (90/210) contre 59% (124/210) par la définition usuelle (ADN VHB (<2000 UI/ml).

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14

Feret, Frank R. "Selected applications of Rietveld-XRD analysis for raw materials of the aluminum industry". Powder Diffraction 28, n. 2 (2 maggio 2013): 112–23. http://dx.doi.org/10.1017/s088571561300016x.

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In the last few decades, X-ray diffraction (XRD) systems have been paramount and irreplaceable in controlling bauxite exploration, as well as Bayer and reduction processes. XRD quantitative phase analysis in the aluminum industry witnessed a steady deployment of the Rietveld method, which at present progressively replaces existing methodologies in research and plant laboratories. Rietveld analysis not only helped to surpass traditional XRD calibration methods, it also opened the door for new applications previously not possible. The use of the Rietveld method to characterize selected materials unique to the aluminum industry, such as bauxite, red mud, and alumina is demonstrated and discussed. This paper also presents how synchrotron-based diffractograms obtained for bauxite and red mud samples allowed a much better understanding of mineralogical representation, and made it possible to leverage their Rietveld quantification. Despite clear advantages, the Rietveld method also has limitations that are revealed. For alumina phase quantification, a dedicated Rietveld analytical program was built with structure data for eight alumina mineralogical phases: alpha, beta (β-Al2O3 = Na2O•11Al2O3), delta, gamma (2), kappa, sigma, and theta. The paper gives unique examples of phase quantification in aluminas of various origins and phase composition.

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Ulrich, Johann F., Melina S. Gräfe, Seema Dhiman, Paul Wienecke, Hans-Dieter Arndt e Thomas Wichard. "Thallusin Quantification in Marine Bacteria and Algae Cultures". Marine Drugs 20, n. 11 (1 novembre 2022): 690. http://dx.doi.org/10.3390/md20110690.

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Thallusin, a highly biologically active, phytohormone-like and bacterial compound-inducing morphogenesis of the green tide-forming macroalga Ulva (Chlorophyta), was determined in bacteria and algae cultures. A sensitive and selective method was developed for quantification based on ultra-high-performance liquid chromatography coupled with electrospray ionization and a high-resolution mass spectrometer. Upon C18 solid phase extraction of the water samples, thallusin was derivatized with iodomethane to inhibit the formation of Fe–thallusin complexes interfering with the chromatographic separation. The concentration of thallusin was quantified during the relevant phases of the bacterial growth of Maribacter spp., ranging from 0.16 ± 0.01 amol cell−1 (at the peak of the exponential growth phase) to 0.86 ± 0.13 amol cell−1 (late stationary phase), indicating its accumulation in the growth medium. Finally, we directly determined the concentration of thallusin in algal culture to validate our approach for monitoring applications. Detection and quantification limits of 2.5 and 7.4 pmol L−1, respectively, were reached, which allow for quantifying ecologically relevant thallusin concentrations. Our approach will enable the surveying of thallusin in culture and in nature and will thus contribute to the chemical monitoring of aquaculture.

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Bezerra, U. T., A. E. Martinelli, D. M. A. Melo, M. A. F. Melo e F. M. Lima. "A correlation between Bogue's equations and Taylor's procedure for the evaluation of crystalline phases in special class Portland oilwell cement clinker". Cerâmica 57, n. 341 (marzo 2011): 122–28. http://dx.doi.org/10.1590/s0366-69132011000100016.

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The crystalline composition of Portland cement clinker is commonly established by Bogue's equations, which are based on a series of assumptions that seldom apply to oilwell cements. This is probably due to the presence of additional oxides and phase reconversion upon cooling of the clinker from the calcination temperature. Important differences are therefore observed between the numerical values yielded by the mathematical equations and image analysis quantification. In this study, the concentration of crystalline phases in oilwell cement was determined using Taylor's procedure, which consists in a system of linear equations corresponding to each one of the four main clinker phases. The results revealed an adequate relationship between this method and phase quantification by optical micrography, especially concerning the contents of aluminate and ferrite.

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Zweck, J., M. Herrmann e H. Hoffmann. "Quantification of micromagnetic structure from Lorentz micrographs". Proceedings, annual meeting, Electron Microscopy Society of America 52 (1994): 894–95. http://dx.doi.org/10.1017/s0424820100172206.

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Defocused imaging of magnetic domain structures is a well-known technique to observe the micromagnetic structures in ferromagnetic thin films. Nevertheless, Lorentz microscopy images are rarely subject to a quantitative evaluation of micromagnetic parameters. In this paper, we offer a new method for quantitative evaluation of ripple wavelengths and ripple angle from Lorentz microscopy images carried out on soft magnetic Ni81Fe19 films. The work was carried out using a Philips CM30 electron microscope with a combined Twin/Lorentz lens.The experiments were performed on thin ferromagnetic films of a Ni81Fe19 alloy. Due to the internal magnetic induction within the specimens, the partial electron waves experience a phase shift proportional to the local in-plane magnetic induction , the specimen's thickness t and the lateral distance x from an arbitrarily chosen point of zero phase shift on the specimen. This phase shift can then be imaged using phase contrast methods similar to HREM. Since the phase shifts and the corresponding deflection angles can be very small, a large defocus is necessary to obtain contrast. This large defocus gives rise to an oscillating phase contrast transfer function for the spatial frequencies under observation as well as to a damping envelope for higher spatial frequencies.

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Breda, M., S. A. Ontiveros Vidal, Jacopo Basoni e Irene Calliari. "Phases Quantification in Duplex Stainless Steels Weldments". Applied Mechanics and Materials 698 (dicembre 2014): 209–14. http://dx.doi.org/10.4028/www.scientific.net/amm.698.209.

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Duplex Stainless Steels (DSS) are very attractive steels and their application is presently of increasing interest, especially as structural materials in aggressive environments. DSS are austeno-ferritic biphasic steels, having an austenite-to-ferrite phase ratio of about one, giving the best combination of mechanical and corrosion-resistance properties. However, these steels must be handled with extreme care, especially if thermal cycles are involved, owing to the formation of dangerous secondary compounds that highly worsen their excellent properties.The production of big pipes requires manufacturing welding operations on steel plates or sheets and the final products must satisfy specific requirements in terms of material properties. DSS approximately contain equal volume fraction of the phases that, in practice, cover a slightly wider range within 40/60 and 60/40. Therefore, since DSS properties depend on phase ratio, ferrite quantification on an industrial scale represents a topic of great interest, which must be as reliable as possible and, at the same time, quickly executable.The present paper gives a comparison of different methods currently employed for ferrite determination in DSS weldments, in order to understand the limits derived from the specific employed technique.

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AL-Farhan, Khalid A. "farhan—a qualitative and quantitative PC program for X-ray powder diffraction". Powder Diffraction 14, n. 1 (marzo 1999): 16–21. http://dx.doi.org/10.1017/s0885715600010241.

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FARHAN is a PC interactive, graphically oriented search–match–identification–quantification computer program for X-ray powder diffraction, which uses a variable intensity-error window (IEW). Both the intensity scale factor and the IEW for each standard phase are estimated by a simple iterative procedure. A new tunable combined figure-of-merit (agreement function) is suggested for estimating the goodness-of-fit of matches. The concentrations of the identified phases may be determined by normalized or generalized RIR quantification methods, if the RIRs of the identified phases are known.

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Liu, Y., R. M. German e R. G. Iacocca. "Microstructure quantification procedures in liquid-phase sintered materials". Acta Materialia 47, n. 3 (febbraio 1999): 915–26. http://dx.doi.org/10.1016/s1359-6454(98)00395-4.

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González-González, Mirna, Karla Mayolo-Deloisa, Marco Rito-Palomares e Robert Winkler. "Colorimetric protein quantification in aqueous two-phase systems". Process Biochemistry 46, n. 1 (gennaio 2011): 413–17. http://dx.doi.org/10.1016/j.procbio.2010.08.026.

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Cai, Xiaomei, Tingping Lei, Daoheng Sun e Liwei Lin. "A critical analysis of the α, β and γ phases in poly(vinylidene fluoride) using FTIR". RSC Advances 7, n. 25 (2017): 15382–89. http://dx.doi.org/10.1039/c7ra01267e.

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A universal but simple procedure for identifying the α, β and γ phases in PVDF using FTIR is proposed and validated. An integrated quantification methodology for individual β and γ phase in mixed systems is also proposed.

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Döbelin, Nicola. "Interlaboratory study on the quantification of calcium phosphate phases by Rietveld refinement". Powder Diffraction 30, n. 3 (11 agosto 2015): 231–41. http://dx.doi.org/10.1017/s088571561500038x.

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An interlaboratory study (ILS, round robin) was conducted to assess the accuracy and precision of the phase quantification of calcium phosphate (CaP) bioceramics by X-ray diffraction (XRD) and Rietveld refinement. For that purpose, a mixture of hydroxyapatite and β-tricalcium phosphate, two CaP phases commonly used in synthetic bone graft substitutes, was prepared and sent to 12 laboratories for XRD analysis. Results from 26 different instruments were received and evaluated statistically according to ASTM E691 – 13. The statistical analysis revealed that the reproducibility standard deviation of phase quantities was approximately two times greater than the repeatability standard deviation, which is obtained by repeating the analysis on a single instrument configuration multiple times. The 95% reproducibility limit for phase quantities was R = ±1.67 wt%. The study also demonstrated that several participants overinterpreted their data in an attempt to refine crystallite sizes of the minor phase.

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Butler, M. A., e D. J. Dyson. "The Quantification of Different Forms of Cristobalite in Devitrified Alumino-Silicate Ceramic Fibres". Journal of Applied Crystallography 30, n. 4 (1 agosto 1997): 467–75. http://dx.doi.org/10.1107/s0021889897001672.

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When heat treated, amorphous alumino-silicate fibres will devitrify into crystalline phases which on cooling become stable at room temperature. X-ray diffraction has been used to identify and quantify the phases present in such products; mullite and two distinct forms of cristobalite have been observed. One form of cristobalite has been identified as α-cristobalite, the second form has been designated as α′-cristobalite. An internal standard approach was used to enable calibration curves to be obtained for the three crystallite phases, including the α′- cristobalite for which no commercially available standard exists. The accuracy of the methods was estimated as ± 5 wt% for all three crystalline phases present. This was achieved by quantifying the proportion of α′-cristobalite in a standard alumino-silicate fibre after heat treatment for 48 h at 1773 K and then using this material as the `standard' for α′-cristobalite. This `standard' contained 32.9 wt% α′-cristobalite, 1.6 wt% α-cristobalite and 65.5 wt% mullite. The exact nature of the α′- cristobalite phase has also been examined using high-temperature X-ray diffraction and differential scanning calorimetry. It has been shown to be more similar in nature to α-cristobalite than β-cristobalite since it undergoes an α′ → β phase transition on heating. Compared with α-cristobalite it has a different lattice size, and both the temperature and enthalpy of the α′ → β phase transition are lower than for the α → β phase transition. It has been proposed that the α′-cristobalite observed is a defect form of α-cristobalite but with a constant amount of defects/substituted cations which gives it a well defined and consistent structure.

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Lindquist, Beth A., e Ryan B. Jadrich. "Uncertainty quantification for a multi-phase carbon equation of state model". Journal of Applied Physics 131, n. 15 (21 aprile 2022): 155104. http://dx.doi.org/10.1063/5.0087210.

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Many physics models have tunable parameters that are calibrated by matching the model output to experimental or calculated data. However, given that calibration data often contain uncertainty and that different model parameter sets might result in a very similar simulated output for a finite calibration data set, it is advantageous to provide an ensemble of parameter sets that are consistent with the calibration data. Uncertainty quantification (UQ) provides a means to generate such an ensemble in a statistically rigorous fashion. In this work, we perform UQ for a multi-phase equation of state (EOS) model for carbon containing the diamond, graphite, and liquid phases. We use a Bayesian framework for the UQ and introduce a novel strategy for including phase diagram information in the calibration. The method is highly general and accurately reproduces the calibration data without any material-specific prior knowledge of the EOS model parameters.

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Goedhart, Joachim, Jean-Jacques Bono e Theodorus W. J. Gadella. "Rapid Colorimetric Quantification of Lipo-chitooligosaccharides from Mesorhizobium loti and Sinorhizobium meliloti". Molecular Plant-Microbe Interactions® 15, n. 9 (settembre 2002): 859–65. http://dx.doi.org/10.1094/mpmi.2002.15.9.859.

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Nod factors are lipids with a chitinlike headgroup produced by gram-negative Rhizobium bacteria. These lipo-chitooligosaccharides (LCOs) are essential signaling molecules for accomplishing symbiosis between the bacteria and roots of legume plants. Despite their important role in the Rhizobium-legume interaction, no fast and sensitive Nod factor quantification methods exist. Here, we report two different quantification methods. The first is based on the enzymatic hydrolysis of Nod factors to release N-acetylglucosamine (GlcNAc), which can subsequently be quantified. It is shown that the degrading enzyme, glusulase, releases exactly two GlcNAc units per pentameric nodulation factor from Mesorhizobium loti factor, allowing quantification of LCOs from Mesorhizobium loti. The second method is based on a specific type of Nod factors that are sulfated on the reducing GlcNAc, allowing quantification analogous to the quantification of sulfolipids. Here, a two-phase extraction method is used in the presence of methylene blue, which specifically forms an ion pair with sulfated lipids. The blue ion pair partitions into the organic phase, after which the methylene blue signal can be quantified. To enable Nod factor quantification with this method, the organic phase was modified and the partitioning was evaluated using fluorescent and radiolabeled sulfated Nod factors. It is shown that sulfated LCOs can be quantified with this method, using sodium dodecyl sulfate for calibration. Both methods allow Nod factor quantification in parallel enabling a fast and easy detection of nanomole quantities of Nod factors. Accurate Nod factor quantification will be crucial for characterization and cross-comparison of the affinity for Nod factors of newly identified Nod factor binding proteins or putative Nod factor receptors.

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Reid, Joel W., e Jason A. Hendry. "Rapid, accurate phase quantification of multiphase calcium phosphate materials using Rietveld refinement". Journal of Applied Crystallography 39, n. 4 (15 luglio 2006): 536–43. http://dx.doi.org/10.1107/s0021889806020395.

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Rietveld refinement has been employed to estimate the crystalline phase compositions of multiphase calcium phosphate mixtures containing calcium hydroxyapatite [Ca5(PO4)3OH], and alpha and beta tricalcium phosphate [Ca3(PO4)2]. Two methods were employed using fixed structural models for all three phases and refining the zero offset, scale factors, lattice parameters and one peak breadth parameter using either a constant background (method A) or a background with two refined parameters (method B). Analysis of a matrix of quantitative standards across a broad spectrum of phase compositions indicates that method A results in small systematic deviations of the Rietveld phase compositions (< 1 wt%) from the nominal values, but the systematic deviations are eliminated by refining the background (method B). The methods require approximately 10 min to complete, and are suitable for quality control of calcium phosphate production (and potentially other multiphase systems) when accuracy, precision and time are all significant considerations.

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Westhuizen, Josiasvd, e J. Prieur Du Plessis. "Quantification of Unidirectional Fiber Bed Permeability". Journal of Composite Materials 28, n. 7 (maggio 1994): 619–37. http://dx.doi.org/10.1177/002199839402800703.

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A new approach to the closed form quantification of the permeability of a bed of unidirectional fibers is proposed. The methodology is founded on the phase average form of the Navier-Stokes equation and is applied here to low Reynolds number laminar flow of an isotropic non-homogeneous Newtonian fluid through a bed of randomly packed unidirectional fibers. Permeability in both the longitudinal and transverse directions is shown to be a function of fiber volume fraction and fiber diameter only. The results are combined in a flow resistance tensor through which the phase-average Navier-Stokes equation is transformed into a practical tool for the numerical analysis of macroscopic flow in geometrically complex composite moldings. Encouraging agreement between the presented analytical solutions and published experimental results is demonstrated.

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Zhong, Qiang, Fazle Hussain e Harindra J. S. Fernando. "Quantification of turbulent mixing in colliding gravity currents". Journal of Fluid Mechanics 851 (19 luglio 2018): 125–47. http://dx.doi.org/10.1017/jfm.2018.488.

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Collision between two identical counterflowing gravity currents was studied in the laboratory with the goal of understanding the fundamental turbulent mixing physics of flow collisions in nature, for example katabatic flows and thunderstorm outflows. The ensuing turbulent mixing is a subgrid process in mesoscale forecasting models, and needs to be parameterized using eddy diffusivity. Laboratory gravity currents were generated by simultaneously removing two identical locks, located at both ends of a long rectangular tank, which separated dense and lighter water columns with free surfaces of the same depth $H$. The frontal velocity $u_{f}$ and the velocity and density fields of the gravity currents were monitored using time-resolved particle image velocimetry and planar laser-induced fluorescence imaging. Ensemble averaging of identical experimental realizations was used to compute turbulence statistics, after removing inherent jitter via phase alignment of successive data realizations by iteratively maximizing the cross-correlation of each realization with the ensemble average. Four stages of flow evolution were identified: initial (independent) propagation of gravity currents, their approach while influencing one another, collision and resulting updraughts, and postcollision slumping of collided fluid. The collision stage, in turn, involved three phases, and produced the strongest turbulent mixing as quantified by the rate of change of density. Phase I spanned $-0.2\leqslant tu_{f}/H<0.5$, where collision produced a rising density front (interface) with strong shear and intense turbulent kinetic energy production ($t$ is a suitably defined time coordinate such that gravity currents make the initial contact at $tu_{f}/H=-0.2$). In Phase II ($0.5\leqslant tu_{f}/H<1.2$), the interface was flat and calm with negligible vertical velocity. Phase III ($1.2\leqslant tu_{f}/H<2.8$) was characterized by slumping which led to hydraulic bores propagating away from the collision area. The measurements included root mean square turbulent velocities and their decay rates, interfacial velocity, rate of change of fluid-parcel density, and eddy diffusivity. These measures depended on the Reynolds number $Re$, but appeared to achieve Reynolds number similarity for $Re>3000$. The eddy diffusivity $K_{T}$, space–time averaged over the spatial extent ($H\times H$) and the lifetime ($t\approx 3H/u_{f}$) of collision, was $K_{T}/u_{f}H=0.0036$ for $Re>3000$, with the area $A$ of active mixing being $A/H^{2}=0.037$.

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Bihan, Dominique G., Thomas Rydzak, Madeleine Wyss, Keir Pittman, Kathy D. McCoy e Ian A. Lewis. "Method for absolute quantification of short chain fatty acids via reverse phase chromatography mass spectrometry". PLOS ONE 17, n. 4 (20 aprile 2022): e0267093. http://dx.doi.org/10.1371/journal.pone.0267093.

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Short chain fatty acids (SCFAs; including acetate, propionate, and butyrate) are an important class of biological molecules that play a major role in modulating host-microbiome interactions. Despite significant research into SCFA-mediated biological mechanisms, absolute quantification of these molecules in their native form by liquid chromatography mass spectrometry is challenging due to their relatively poor chromatographic properties. Herein, we introduce SQUAD, an isotope-based strategy for absolute quantification of SCFAs in complex biological samples. SQUAD uses aniline derivatization in conjunction with isotope dilution and analysis by reverse-phase liquid chromatography mass spectrometry. We show that SQUAD enables absolute quantification of biologically relevant SCFAs in complex biological samples with a lower limit of detection of 40 nM and a lower limit of quantification ranging from 160 nM to 310 nM. We observed an intra- and inter-day precision under 3% (relative standard deviation) and errors in intra- and inter-day accuracy under 10%. To demonstrate this quantification strategy, we analyzed SCFAs in the caecal contents of germ free versus conventionally raised specific pathogen free (SPF) mice. We showed that acetate was the most abundant SCFA in both types of mice and was present at 200-fold higher concentration in the SPF mice. We also illustrated the use of our quantification strategy in in vitro microbial cultures from five different species of bacteria grown in Mueller Hinton media. This study illustrates the diverse SCFA production rates across microbial taxa with acetate production serving as one of the key differentiating factors across the species. In summary, we introduce an isotope dilution strategy for absolute quantification of aniline-dativized SCFAs and illustrate the utility of this approach for microbiome research.

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Murakami, Katsura, Yoshie Sugimoto e Naofumi Umigai. "Quantification of Crocetin in Foods by Solid-Phase Extraction". Nippon Shokuhin Kagaku Kogaku Kaishi 65, n. 8 (15 agosto 2018): 393–400. http://dx.doi.org/10.3136/nskkk.65.393.

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32

Polavaram, Krishna C., e Nishant Garg. "Enabling phase quantification of anhydrous cements via Raman imaging". Cement and Concrete Research 150 (dicembre 2021): 106592. http://dx.doi.org/10.1016/j.cemconres.2021.106592.

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33

HATTORI, Renta, Daisuke MINATO, Suguru GOTO e Toyoharu NAWA. "QUANTIFICATION OF AN INTERMEDIATE PHASE DURING HYDRATION OF CEMENT". Cement Science and Concrete Technology 65, n. 1 (2011): 46–53. http://dx.doi.org/10.14250/cement.65.46.

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34

de Haan, Michiel W., Jos M. A. van Engelshoven, Alphons J. H. M. Houben, Dave W. Kaandorp, Alfons G. H. Kessels, Abraham A. Kroon e Peter W. de Leeuw. "Phase-Contrast Magnetic Resonance Flow Quantification in Renal Arteries". Hypertension 41, n. 1 (gennaio 2003): 114–18. http://dx.doi.org/10.1161/01.hyp.0000047466.98321.9d.

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35

Wei, Y., S. Liang e X. Gao. "Phase quantification in cementitious materials by dynamic modulus mapping". Materials Characterization 127 (maggio 2017): 348–56. http://dx.doi.org/10.1016/j.matchar.2017.02.029.

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36

Lee, Jung Min, Z. U. Shin, Gafurjon T. Mavlonov, Ibrokhim Y. Abdurakhmonov e Tae-Hoo Yi. "Solid-Phase Colorimetric Method for the Quantification of Fucoidan". Applied Biochemistry and Biotechnology 168, n. 5 (18 agosto 2012): 1019–24. http://dx.doi.org/10.1007/s12010-012-9837-y.

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37

Takeoka, Tsuneyuki, Yukito Shinohara, Kosuke Mori e Koichi Furumi. "Solid-phase immunofluorometric assay for quantification of CSF immunoglobulins". Journal of the Neurological Sciences 96, n. 2-3 (maggio 1990): 229–40. http://dx.doi.org/10.1016/0022-510x(90)90135-a.

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38

Somer, A., J. G. Camilotti, A. Gonçalves, C. Bonardi, G. K. Cruz, F. L. Beltrame, F. Sato, N. G. C. Astrath e A. Novatski. "Polyvinylpyrrolidone Quantification in Paracetamol Using Phase-Resolved Photoacoustic Method". Spectroscopy Letters 48, n. 6 (21 gennaio 2015): 427–30. http://dx.doi.org/10.1080/00387010.2014.902853.

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39

Xue, Yujia, Shiyi Cheng, Yunzhe Li e Lei Tian. "Reliable deep-learning-based phase imaging with uncertainty quantification". Optica 6, n. 5 (7 maggio 2019): 618. http://dx.doi.org/10.1364/optica.6.000618.

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40

Niknazar, Hamid, Ali Motie Nasrabadi e Mohammad Bagher Shamsollahi. "Volumetric behavior quantification to characterize trajectory in phase space". Chaos, Solitons & Fractals 103 (ottobre 2017): 294–306. http://dx.doi.org/10.1016/j.chaos.2017.06.018.

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41

McAuley, Grant, Matthew Schrag, Pál Sipos, Shu-Wei Sun, Andre Obenaus, Jaladhar Neelavalli, E. Mark Haacke, Barbara Holshouser, Ramóna Madácsi e Wolff Kirsch. "Quantification of punctate iron sources using magnetic resonance phase". Magnetic Resonance in Medicine 63, n. 1 (1 dicembre 2009): 106–15. http://dx.doi.org/10.1002/mrm.22185.

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42

Yamada, Tesshi. "Quantification of Biomarker Proteins Using Reverse‐Phase Protein Arrays". PROTEOMICS – Clinical Applications 14, n. 4 (28 febbraio 2020): 1900120. http://dx.doi.org/10.1002/prca.201900120.

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43

Korcakova, Leona, John Hald e Marcel A. J. Somers. "Quantification of Laves phase particle size in 9CrW steel". Materials Characterization 47, n. 2 (agosto 2001): 111–17. http://dx.doi.org/10.1016/s1044-5803(01)00159-0.

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44

Kachhiya, Hetaben, Rutvik Pandya, Krunal Solanki, Jinal Tandel, Usmangani Chhalotiya e Dimal Shah. "Reversed phase-HPLC-PDA method for quantification of Desidustat". Journal of Chemical Metrology, n. 1 (9 novembre 2023): 1–10. http://dx.doi.org/10.25135/jcm.95.2307.2839.

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45

Gummadi, Sowjanya, e Rajya Lakshmi Nimmagadda. "Quantification of Pitolisant: A RP - HPLC study". YMER Digital 21, n. 06 (26 giugno 2022): 896–907. http://dx.doi.org/10.37896/ymer21.06/89.

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Abstract (sommario):

Objective An attempt was made to develop a simple, isocratic and robust reverse phase high performance liquid chromatographic method for Pitolisant. Material and methods An Inertsil octa decyl silane column and photo diode array detector were employed for the quantification of Pitolisant at 268 nm using a mobile phase consisting of acetonitrile and 0.1 % v/v formic acid (90:10 % v/v) at a flow rate of 1.0 mL/min. for the efficient elution of Pitolisant. Results The developed method was validated for various parameters and the linearity range was observed at 25-150 µg/mL. The correlation coefficient, limit of detection and limit of quantification calculated from the calibration curve were 0.9998, 0.3 µg/mL and 1.0 µg/mL respectively. The mean percentage recovery was 99.9 %. The formulation was subjected to stress at various conditions resulting in minor degradants at different retention times. Conclusion An isocratic, fast, robust reverse phase – high performance liquid chromatographic method was developed which can be exploited for the estimation of Pitolisant in bulk and tablets. Key words: Pitolisant, High performance liquid chromatography, Photo diode array detector, Limit of detection, Degradation studies

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46

Kipura, Tobias, Madlen Hotze, Alexa Hofer, Anna-Sophia Egger, Lea E. Timpen, Christiane A. Opitz, Paul A. Townsend, Lee A. Gethings, Kathrin Thedieck e Marcel Kwiatkowski. "Automated Liquid Handling Extraction and Rapid Quantification of Underivatized Amino Acids and Tryptophan Metabolites from Human Serum and Plasma Using Dual-Column U(H)PLC-MRM-MS and Its Application to Prostate Cancer Study". Metabolites 14, n. 7 (30 giugno 2024): 370. http://dx.doi.org/10.3390/metabo14070370.

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Amino acids (AAs) and their metabolites are important building blocks, energy sources, and signaling molecules associated with various pathological phenotypes. The quantification of AA and tryptophan (TRP) metabolites in human serum and plasma is therefore of great diagnostic interest. Therefore, robust, reproducible sample extraction and processing workflows as well as rapid, sensitive absolute quantification are required to identify candidate biomarkers and to improve screening methods. We developed a validated semi-automated robotic liquid extraction and processing workflow and a rapid method for absolute quantification of 20 free, underivatized AAs and six TRP metabolites using dual-column U(H)PLC-MRM-MS. The extraction and sample preparation workflow in a 96-well plate was optimized for robust, reproducible high sample throughput allowing for transfer of samples to the U(H)PLC autosampler directly without additional cleanup steps. The U(H)PLC-MRM-MS method, using a mixed-mode reversed-phase anion exchange column with formic acid and a high-strength silica reversed-phase column with difluoro-acetic acid as mobile phase additive, provided absolute quantification with nanomolar lower limits of quantification within 7.9 min. The semi-automated extraction workflow and dual-column U(H)PLC-MRM-MS method was applied to a human prostate cancer study and was shown to discriminate between treatment regimens and to identify metabolites responsible for discriminating between healthy controls and patients on active surveillance.

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47

Li, Xiaohu, Sergio Soria, Weimin Gan, Michael Hofmann, Michael Schulz, Markus Hoelzel, Heinz-Günter Brokmeier e Winfried Petry. "Multi-scale phase analyses of strain-induced martensite in austempered ductile iron (ADI) using neutron diffraction and transmission techniques". Journal of Materials Science 56, n. 8 (10 dicembre 2020): 5296–306. http://dx.doi.org/10.1007/s10853-020-05619-x.

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AbstractThe content of strain-induced martensite in austempered ductile iron has been quantitatively determined using three different kinds of neutron methods: (1) high-resolution powder diffraction with subsequent standard Rietveld refinement, (2) phase quantification using pole figure measurements and (3) Bragg edge neutron transmission. The accuracy and scope of applications of these neutron diffraction and imaging techniques for phase quantification have been compared and discussed in detail. Combination of these methods has been confirmed as effective for dealing with problems like peak overlap in multi-phase materials and texture formation after plastic deformation. Further, the results highlight the potential of using single peak pole figure data for quantitative phase analysis with high accuracy.

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48

Clauss, R. P., e M. M. Sathekge. "Criteria and Quantification of Fibrous Dysplasia on MDP Scanning". Nuklearmedizin 34, n. 06 (1995): 229–31. http://dx.doi.org/10.1055/s-0038-1629719.

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SummaryEleven patients with histologically proven fibrous dysplasia (biopsy) were imaged with 3-phase bone scanning, using 99mTc-MDP. Ten had monostotic and one had polyostotic fibrous dysplasia. The perfusion (phase I) and uptake (phase III) of monostotic lesions was compared to the normal contralateral side and the rest of the skeleton was inspected for other abnormalities. Lesions presented with slightly increased perfusion (1.65 normal ± 0.907) and markedly increased uptake of tracer (6.0 normal ± 2.58). Other features that were noted are high spinal and scapula and poor renal tracer uptake.

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Larionova, D., I. Goryacheva, C. Van Peteghem e S. De Saeger. "Thin-layer chromatography of aflatoxins and zearalenones with β-cyclodextrins as mobile phase additives". World Mycotoxin Journal 4, n. 2 (1 gennaio 2011): 113–17. http://dx.doi.org/10.3920/wmj2010.1267.

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The conditions of thin-layer chromatography separation of related aflatoxins and zearalenones in the presence of β-cyclodextrin and 2-hydroxypropyl-β-cyclodextrin were studied. Effects of the stationary phase and mobile phase composition were investigated. Analytical conditions for the separation and simultaneous semi-quantitative fluorescence detection of aflatoxins B1, B2, G1 and G2, zearalenone and α-zearalenol on normal-phase plates (silica gel, polyamide) and reversed-phase plates (C18) with cyclodextrin modified mobile phase were optimised. The limit of quantification was found 2 ng per spot for aflatoxin G1 and aflatoxin B2, 3.5 ng for aflatoxin B1 and aflatoxin G2 and 100 ng per spot for zearalenone and α-zearalenol. Addition of cyclodextrins to the mobile phase allowed a decrease in the amount of toxic solvents, and improved separation characteristics, but did not improve the limit of quantification.

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Saeed, Muhammad Asad, Muhammad Tayyab Ansari, Bashir Ahmad Ch e Muhammad Zaman. "RP-HPLC Method for the Determination and Quantification of Artesunate". Journal of Chromatographic Science 58, n. 8 (28 luglio 2020): 695–99. http://dx.doi.org/10.1093/chromsci/bmaa037.

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Abstract A simple, rapid and cost-effective reverse phase high-performance liquid chromatographic (RP-HPLC) method was developed for the quantification of artesunate. C18 Promosil (ODS, 150 × 4.6 mm, 5 μm) column was used as stationary phase to separate the drug. Mobile phase comprised of ethanol: water (65:35) having pH 4.5 was run isocratically at a flow rate of 1 mL/min at 27°C. The method was validated according to ICH guidelines for linearity, precision, accuracy, robustness, specificity, limit of detection (LOD) and limit of quantification (LOQ). The method was found accurate, precise and robust with an average retention time of 4.509 min and 0.5357 %RSD. Good linearity was observed in the concentration range of 2–10 mg/ml with regression coefficient R2 value of 0.9995 and slope value of 369,928. Conclusively, as per ICH norms, the developed method was successfully validated and used for the quantification of artesunate in fast dissolving tablets (FDTs).

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