126,352 research outputs found
Going Beyond Counting First Authors in Author Co-citation Analysis
No full textThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Dispelling the Myths Behind First-author Citation Counts
No full textWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
IMS: The New Generation of Internet-Protocol-Based Multimedia Services
No full textLegacy networks, both fixed and mobile, which were originally designed for voice communications, are progressively migrating to new infrastructures that promise to revolutionize the services offered. In this paper, we will cover this new generation of personal communication services, with an emphasis on the family of Internet protocol (IP)-based multimedia subsystem (IMS)-aided infrastructure that relies on the session initiation protocol (SIP). As a benefit, the end users will enjoy a new generation of personal communications services that are accessible anywhere and anytime. These services are timedia subsystem (IMS)-aided infrastructure that relies on the directly related to the end users rather than to their diverse devices. It is anticipated that the new deployments of next-of the IMS technology. generation networks (all-IP based) will accelerate the adoptio
DESIGN OF EXPERIMENTS AND RESPONSE SURFACE METHODOLOGY AS POWERFUL TOOLS FOR THE OPTIMIZATION OF SAMPLE PREPARATION AND INSTRUMENTAL ANALYSIS
No full textThe Design of Experiments (DoE) is a multivariate approach aimed at a rational plan of the experiments, which allows to compute mathematical models able to describe our system. It permits to understand how the variables influence a response and interact among each other, avoiding the costly and long “one variable at a time” strategy [1]. Depending on the purpose, it is possible to choose among a selection of experimental designs, such as Plackett-Burman, Box-Behnken and central composite designs. In our lab, DoE has been successfully implemented to both sample treatment and instrumental analysis, in different applications, herein presented.
If several variables are involved in complex problems, a first screening followed by a response surface design may be necessary. This was the case of the optimization of the analysis of five phytoestrogens in soy-food. A Plackett-Burman design allowed to select the significant variables affecting the accuracy; then, Box-Behnken design was employed to build the response surfaces and find the optimal experimental conditions.
In the analysis of 21 bioactive compounds by non-aqueous reverse phase chromatography, a simple central composite design allowed to see how flow, temperature and gradient velocity influenced chromatographic separation. Just seventeen runs (less than one day of analyses) were necessary to gather the data and then define the best compromise to separate coeluted peaks.
The optimization of a dispersive solid phase extraction for polycyclic aromatic hydrocarbons (PAHs) in seawater was rapidly achieved thanks to the Plackett-Burman design. This screening design (just 12 experiments) allowed to reveal that only one variable out of 9 significantly affected the recovery, thus avoiding the performance of a large number of experiments. In a similar application to botanical supplements, the D-optimal design was employed for optimization. The knowledge acquired in the previous study permitted to select only 4 variables: their effect on the PAHs recovery was studied by performing 18 experiments. The response surfaces allowed to rapidly identify the significant variables and optimal conditions.
In all these case studies DoE demonstrated to be a powerful tool to obtain the maximum information with the minimum experimental effort
Phytoestrogens in soy‐based meat substitutes: Comparison of different extraction methods for the subsequent analysis by liquid chromatography‐tandem mass spectrometry
No full textThis paper presents the development of an efficient extraction procedure followed by a high performance liquid chromatography‐tandem mass spectrometry (HPLC‐MS/MS) method for the determination of five phytoestrogens (genistein, daidzein, formononetin, biochanin A, and coumestrol) in soy‐based meat substitutes. The HPLC‐MS/MS method, with electrospray ionization (ESI) source, was optimized to obtain high specificity and sensitivity, as well as rapidity of the analysis. Three extraction techniques were applied to soy burgers and compared: ultrasound assisted extraction, ultrasound assisted extraction followed by solid phase extraction and the Quick Easy Cheap Effective Rugged and Safe (QuEChERS) methodology. Both ultrasound assisted extraction and QuEChERS proved to be suitable for the determination of phytoestrogens, showing high recoveries, in the range of 86% to 99% and 75% to 105%, respectively. Matrix effect was evaluated, and ion suppression was observed for coumestrol and formononetin, demonstrating the importance of matrix effect
assessment when complex samples are analyzed by HPLC‐ESI‐MS.
The complete analytical protocols provided limits of detection and quantitation in soyburgers
at the ng g−1 level for all the considered phytoestrogens. Some soy burger samples
were analyzed by both ultrasound assisted extraction and QuEChERS followed by
HPLC‐MS/MS. High concentration levels of daidzein and genistein (2‐59 μg g−1 and 2‐
72 μg g−1, respectively) were found; formononetin was in the range of 5 to 26 ng g−1,
while biochanin A and coumestrol were under the limit of quantitation in all samples.
The results obtained with the two different sample treatment were in good agreement,
proving the precision and accuracy of the described techniques
The experimental design approach to the optimization of a simple quick easy cheap effective rugged and safe method for the analysis of phytoestrogens in complex soy‐based food
No full textThe present paper deals with the multivariate optimization of an extraction-purification strategy for the determination of phytoestrogens (daidzein, genistein,coumestrol, formononetin, and biochanin A) in soy-based meat substitutes by highperformance liquid chromatography with tandem mass spectrometry. For a reliablequantitation of these new concerning compounds in such a complex matrix, recov-ery and matrix effect must be carefully evaluated. Therefore, two sequential experi-mental designs were used to optimize the sample-pretreatment of soy-based burgers:the chosen technique was the quick, easy, cheap, effective, rugged and safe method-ology, which does not require any particular facility or instrumentation. Thanks tothe first screening design (Plackett-Burman), the significant factors influencing thestudied responses were identified and further investigated through a response surfacedesign (Box-Behnken). The optimal values of the variables (volume of extraction sol-vent mix/sample mass ratio and two clean-up sorbents) led to quantitative recoveries(97–104%) and low ion suppression (matrix effect 60–93%) for all analytes. This opti-mized method was characterized by low detection limits (0.2–1.5 ng/g) and excellentintraday precision (RSD 2–4%). It was applied to the determination of the consideredcompounds in several soy-burgers from the Italian market, detecting low ng/g levels(up to 40 ng/g) of coumestrol, formononetin, and biochanin A, and high concentra-tions (7.9–78μg/g) of genistein and daidzein
From Roots to Leaves: The Capacity of <i>Micromonospora</i> to Colonize Different Legume Tissues
No full textsponsorship: This research was supported by the Ministerio de Ciencia e Innovacion (Ministry of Science, Innovation and Universities) under project PGC2018-096185-B-I00 (M. E. Trujillo). P. Benito received an FPI scholarship from the Spanish Ministry of Science and Innovation (MICINN), L. Carro received a postdoctoral fellowship from the University of Salamanca, and M. Ortuzar received a Ph.D. grant from the Junta de Castilla y Leon (Spain). (Ministerio de Ciencia e Innovacion (Ministry of Science, Innovation and Universities)|PGC2018-096185-B-I00, Spanish Ministry of Science and Innovation (MICINN), University of Salamanca, Junta de Castilla y Leon (Spain))status: Publishe
Converting a Moka-Pot into a Green Extraction Tool for the Analysis of Performance Enhancing Drugs via HPLC-MS/MS in Dietary Supplements.
No full textIn recent years, quick, green and effective extraction strategies became a need in analytical laboratories to support environmental sustainability. Along with the development of more powerful hyphenated instrumental techniques, this led to advanced technologies enabling extremely efficient procedures to be achieved with very low limits of detection. Moka-Pot Extraction (MPE) is a new strategy based on the use of a Moka pot, that consists of three principal aluminium parts: the boiling chamber, which is filled in water; the funnel filter, in which ground coffee is added; and the collecting chamber, where the drink is collected [1]. MPE works at slightly higher pressure than the atmospheric and at high temperatures, and the extraction encompasses two different mechanisms: (i) during the normal phase a solid-liquid extraction occurs, then (ii) the volcanic phase involves a solid-liquid-vapour extraction, thus allowing a higher extraction yield [1]. This consideration led to the conception of the use of a Moka pot as a device for sample preparation for extracting targeted compounds in Dietary Supplements (DS) [2]. DS are widely used worldwide; however, they are often the cause of unintended doping for professional athletes due to the presence of prohibited substances, sometimes not declared in the product information label [3,4]. This study aimed to optimise the extraction efficiency of MPE (including performance enhancing compounds - PECs) and applying the methodology to several DS samples.
As a first proof-of-concept, MPE conditions for the extraction of polar compounds from DS were optimised. A 24-1 fractional factorial design of experiments was implemented, considering the following factors: heating temperature; solvent pH; content of organic modifier (acetonitrile); amount of sample within the funnel filter. The multivariate approach allowed easy determination of the most influential variables (which resulted in the amount of sample, and the interaction between temperature and organic modifier content). From the response surface plots, potentially optimal conditions were suggested [2]. These were firstly validated for 17 target analytes by processing a spiked matrix which did not present any of them, and both the recoveries (between 52 and 134 %) and matrix effects (always negligible or moderate at 100-fold dilution) were calculated from the peak areas obtained after filtration, dilution and analysis. These conditions were applied to real samples: (i) through Hydrophilic Interaction Liquid Chromatography – tandem Mass Spectrometry (MS) 7 of the 17 tested compounds, including artificial sweeteners, methylxanthines and taurine, were detected and quantified [2]; (ii) via a Liquid Chromatography - High Resolution MS analysis the extracts were further screened for more than a hundred PECs.
The obtained concentrations were then compared to those declared on the labels (when available) to check for any possible mislabelling, and to the maximum recommended doses for caffeine and taurine, considering also the daily servings. Interestingly, one DS sample contained caffeine and taurine above the permitted limits [2]. To evaluate the performances of this method, the results were compared with those of a Salt-Assisted Liquid-Liquid Extraction (SALLE) previously developed [5], both in terms of extraction efficiencies and greenness. The two methodologies were quite comparable, even if the MPE was much more efficient in the extraction of taurine, which was not included in the subset of analytes for which SALLE has been optimized [5]. Regarding the greenness, MPE produced higher amounts of waste, but if a smaller Moka was available (e.g. 10 times smaller), it would be even greener than the SALLE [2]. To sum up, this work proved that a Moka-pot, a simple household product, could be used as an effective extraction tool. After the optimization of the method for a few compounds belonging to different classes, the list of targeted analytes was widened, focusing on PECs included in the World Anti-Doping Agency’s prohibited list. Thanks to the promising results, the application of such a simple household device could be encouraged, by exploring the extraction of different classes of compounds in other matrices.
References
[1] L. Navarini, E. Nobile, F. Pinto, A. Scheri, F. Suggi-Liverani, Experimental investigation of steam pressure coffee extraction in a stove-top coffee maker, Applied Thermal Engineering 29 (2009) 998–1004.
[2] M. Baglietto, B. Benedetti, M. Di Carro, E. Magi, Assessing the potentialities of an easy-to-use sample treatment strategy: Multivariate investigation on “Moka extraction” of typical ingredients from dietary supplements, Advances in Sample Preparation 10 (2024) 100110.
[3] J.M. Martínez-Sanz, I. Sospedra, C.M. Ortiz, E. Baladía, A. Gil-Izquierdo, R. Ortiz-Moncada, Intended or Unintended Doping? A Review of the Presence of Doping Substances in Dietary Supplements Used in Sports, Nutrients 9 (2017) 1093.
[4] S. Odoardi, E. Castrignanò, S. Martello, M. Chiarotti, S. Strano-Rossi, Determination of anabolic agents in dietary supplements by liquid chromatography-high-resolution mass spectrometry. Food Additives & Contaminants: Part A, 32(5), (2015) 635–647.
[5] M. Baglietto, B. Benedetti, M. Di Carro, E. Magi, Polar licit and illicit ingredients in dietary supplements: chemometric optimization of extraction and HILIC-MS/MS analysis, Anal Bioanal Chem 416 (2024) 1679–1695
Pragmatic Case Studies as a Source of Unity in Applied Psychology
No full textTo unify or not to unify applied psychology: that is the question. In this article we review pendulum swings in the historical efforts to answer this question—from a comprehensive, positivist, “top-down,” deductive yes between the 1930s and the early 60s, to a postmodern no since then. A rationale and proposal for a limited, “bottom-up,” inductive yes in applied psychology is then presented, employing a case-based paradigm that integrates both positivist and postmodern themes and components. This paradigm is labeled “pragmatic psychology” and, its specific use of case studies, the “Pragmatic Case Study Method” (“PCS Method”). We call for the creation of peer-reviewed journal-databases of pragmatic case studies as a foundational source of unifying applied knowledge in our discipline. As one example, the potential of the PCS Method for unifying different angles of theoretical regard is illustrated in an area of applied psychology, psychotherapy, via the case of Mrs. B. The article then turns to the broader historical and epistemological arguments for the unifying nature of the PCS Method in both applied and basic psychology.Peer reviewe
Fast derivatization procedure for the analysis of phytoestrogens in soy milk by gas chromatography tandem mass spectrometry
No full textIn this work an optimized GC–MS/MS method, based on a simple and fast derivatization procedure, is proposed for the determination of five phytoestrogens (formononetin, daidzein, coumestrol, genistein and biochanin A) in soy milk. A systematic study of the instrumental analysis conditions was carried out, optimizing different MS acquisition parameters. At the same time, the derivatization procedure was optimized testing three silylating reagents. Among them, N,O-bis-(trimethylsilyl) trifluoroacetamide (BSTFA) was chosen as the most suitable derivatization reagent and an experimental design was performed to find the best conditions for the silylation reaction. The results showed the independence of the derivatization efficiency from the heating treatment applied before analysis, enabling the derivatization directly in the injection port; moreover, the use of a temperature programmed injection enhanced sensitivity and precision of the analysis. The described optimization steps allowed a significant gain in the sensitivity of the overall method, leading to detection limits of 0.1–17.7 μg L− 1, which are lower or comparable to values reported in the literature for GC–MS analysis of these analytes. High specificity was reached as well, thanks to the careful study of the conditions for tandem MS detection. Precision was good for formononetin, daidzein and coumestrol, with coefficients of variance of 4.7–6.1%; on the contrary, the analysis of genistein and biochanin A was characterized by low precision, probably due to poor stability of the corresponding derivatives. The method was tested on some soy milk samples from the Italian market, proving its suitability for the analysis of phytoestrogens in this complex matrix
- …
