Search results for "Analytical"
showing 10 items of 9586 documents
Making sense of women entrepreneurship research : a qualitative meta-analytical review
2016
In this study, we explore how extant literature contributes to the development in women entrepreneurship research in terms of both theoretical and practical perspectives. Accordingly, an ostensible tendency can be seen as women entrepreneurship shifting from a marginalized discipline to a mainstream concept concerning more multi-dimensional attributes. Gender has been used as a lens into studies and it is understood as a socially-constructed process – to simply conduct comparative analysis between sexes cannot lead to more fruitful research results – women entrepreneurs needs a medium to undergo their significant contributions and important roles. Literature materials are chosen with the ke…
Functional investigation and applications of the acetylesterase activity of the Citrus sinensis (L.) Osbeck peel
2020
The hydrolysis of acetyl moieties on a set of commercially relevant substrates was performed by employing the whole tissue of Citrus sinensis (L.) Osbeck peel as an efficient biocatalyst in mild reaction conditions with high degree of regioselectivity. The reaction is done in aqueous media and the product is easily recovered. Optimal reaction conditions were deduced and two practical applications were investigated: the elaboration of acetylglicerols and the preparation of vitamin K1 precursor. Peel waste (flavedo and albedo) from orange juice manufacturing was successfully employed as a biocatalyst.
Incorporation of zeolitic imidazolate framework (ZIF-8)-derived nanoporous carbons in methacrylate polymeric monoliths for capillary electrochromatog…
2017
A series of metal organic frameworks-derived nanoporous carbons originating from zeolitic imidazolate framework-8 (ZIF-8) crystals as precursors have been prepared via varying the preparation conditions. The ZIF-8-derived carbons were subsequently admixed in the methacrylate monomers containing polymerization mixtures and polymerized to obtain monolithic columns for capillary electrochromatography (CEC). The effect of particle size and content of the ZIF-8-derived carbon materials in the polymerization mixture on the performance of the hybrid monolithic columns was investigated in detail. The resulting composites were characterized using scanning electron microscopy. Using short time UV-ini…
Boronate affinity sorbents based on thiol-functionalized polysiloxane-polymethacrylate composite materials in syringe format for selective extraction…
2021
Abstract In this work, two novel boronate affinity monolithic materials able to extract glycopeptides within a polypropylene syringe are described and compared. The first material was synthesized from glycidyl methacrylate (GMA)-based monoliths modified with poly-3-mercaptopropyl-methylsiloxane (PMPMS) followed by attachment of 4-vinylphenylboronic acid (VPBA) via thiol-ene click reaction. The second material was prepared by using gold nanoparticle (AuNP)-modified monoliths as substrate followed by subsequent attachment of PMPMS and VPBA. The resulting materials were used as sorbents for solid-phase extraction (SPE) to selectively preconcentrate glycopeptides from horseradish peroxidase (HR…
Advances in Fourier transform infrared spectroscopy of natural glasses: From sample preparation to data analysis
2014
Fourier transform infrared spectroscopy (FTIR) is an analytical technique utilized to measure the concentrations of H and C species in volcanic glasses. Water and CO2 are the most abundant volatile species in volcanic systems. Water is present in magmas in higher concentrations than CO2 and is also more soluble at lower pressures, and, therefore it is the dominant volatile forming bubbles during volcanic eruptions. Dissolved water affects both phase equilibria and melt physical properties such as density and viscosity, therefore, water is important for understanding magmatic processes. Additionally, quantitative measurements of different volatile species using FTIR can be achieved at high s…
The effect of the pore structure and zeta potential of porous polymer monoliths on separation performance in ion-exchange mode.
2007
Most often, in bioseparations involving charged macromolecules, the chromatographic systems have low Reynolds and high Peclet numbers. For such systems, an expression is developed and presented in this work for evaluating the throughput in polymeric monoliths where ion-exchange adsorption occurs, as a function of (i) the pressure drop along the length of the monolith, (ii) the functional form and width of the throughpore-size distribution of the monolith, and (iii) the magnitude of the zeta potential on the surface of the throughpores of the monolith. Gaussian and log-normal throughpore-size distributions whose mean throughpore-size and standard deviation values are based on experimentally …
Application of field portable EDXRF spectrometry to analysis of pigments of Levantine rock art
2010
The results of the analyses of elemental composition of red and black pigments of Levantine rock art from La Saltadora rock shelters (Valltorta gorge, Castellon, Spain) are presented in this paper. Nondestructive analyses were carried out using a portable energy dispersive X-ray fluorescence (EDXRF) spectrometer developed for in situ analysis. The results revealed the strong presence of calcium in all the analyzed locations due to the contribution of the underlying calcareous bedrock and the overlying crust. Iron is the main element detected in red pigments and manganese in black pigments. Iron and calcium ratios have been found indicative of the degree of preservation of the pictorial laye…
Chemical composition of the essential oil from Pulicaria vulgaris var. graeca (Sch.-Bip.) Fiori (Asteraceae) growing wild in Sicily and its antimicro…
2015
In this study the chemical composition of the essential oil from aerial parts of Pulicaria vulgaris var. graeca (Sch.-Bip.) Fiori collected in Sicily was evaluated by GC and GCâMS. The main components of P. vulgaris var. graeca oil were hexadecanoic acid (21.7%), β-caryophyllene (14.3%) and geranyl propionate (8.2%). The comparison with other studied oils of genus Pulicaria is discussed. Antibacterial activity against several bacteria, including some ones infesting historical art craft, was also determined.
Glyphosate Sensor Based on Nanostructured Water-Gated CuO Field-Effect Transistor
2022
This research presents a comparative analysis of water-gated thin film transistors based on a copper oxide (CuO) semiconductor in the form of a smooth film and a nanostructured surface. A smooth CuO film was deposited through reactive magnetron sputtering followed by annealing in atmosphere at a temperature of 280 (Formula presented.) C. Copper oxide nanostructures were obtained by hydrothermal synthesis on a preliminary magnetron sputtered 2 nm thick CuO precursor followed by annealing at 280 (Formula presented.) C. An X-ray diffraction (XRD) analysis of the samples revealed the presence of a tenorite (CuO) phase with a predominant orientation of (002). Scanning electron microscopy (SEM) a…
Epistemic network analyses of economics students' graph understanding. An eye-tracking study
2020
Learning to solve graph tasks is one of the key prerequisites of acquiring domain-specific knowledge in most study domains. Analyses of graph understanding often use eye-tracking and focus on analyzing how much time students spend gazing at particular areas of a graph&mdash