Search results for " sample"

Trace analysis by ion mobility spectrometry: From conventional to smart sample preconcentration methods. A review.

2018

Ion mobility spectrometry (IMS) is a rapid and high sensitive technique widely used in security and forensic areas. However, a lack of selectivity is usually observed in the analysis of complex samples due to the scarce resolution of the technique. The literature concerning the use of conventional and novel smart materials in the pretreatment and preconcentration of samples previous to IMS determinations has been critically reviewed. The most relevant strategies to enhance selectivity and sensitivity of IMS determinations have been widely discussed, based in the use of smart materials, as immunosorbents, aptamers, molecularly imprinted polymers (MIPs), ionic liquids (ILs) and nanomaterial. …

Brief report - "Every little thing gonna be all right" (at least for me): Dispositional optimists display higher optimistic bias for infection during…

2020

Dispositional optimism (DO) and optimistic bias (OB) in risk perception are two distinct phenomena and previous studies about their reciprocal relationship report contrasting results. In the present study, we focused on the relationship between DO and OB when reporting the personal and the other persons' risk about COVID-19. We hypothesized that, when facing a largely uncontrollable risky situation (like the recent pandemic), dispositional optimists would defensively increase their OB about the current risks. A convenience sample of 414 Italian participants aged 18 or older were recruited. They completed a questionnaire investigating past protective behaviors, DO, perceived personal and oth…

Oxygen isotope and salinity measurements of coastal surface waters in the Gulf of Maine

2020

These data include salinity and oxygen isotope measurements of water samples collected from coastal sites along the Gulf of Maine between 2003 and 2015. In particular, a suite of samples were collected along the coast of Maine, east of Penobscot Bay, on a monthly basis between April 2014 and March 2015. These data also include several freshwater samples collected from the Kennebec and Penobscot Rivers on a semi-monthly basis in 2014 and 2015. For the water samples with sample IDs starting with DSW, JSW, NSW, or OSW: The water samples were collected by hand from shore or boat using French square glass bottles with phenolic polycone lined caps. Salinity was measured using a Oakton SALT 6+ han…

On-line in-tube solid phase microextraction coupled to capillary liquid chromatography-diode array detection for the analysis of caffeine and its met…

2019

Abstract In-tube solid phase microextraction (IT-SPME) coupled on-line to capillary liquid chromatography with diode array detection provides a simple and fast analytical methodology for the simultaneous quantitation of caffeine and its three primary metabolites (theobromine, paraxanthine and theophylline) in micro samples of serum, saliva and urine matrices. The sample amount required for one analysis was only 2.5 μL of saliva, 6.25 μL of serum or 40 μL of urine, a requirement for its implementation in a hospital laboratory for preterm newborns, where sample availability is a major problem. In standard conditions, 25 μL of diluted saliva or serum (or 100 μL of urine) were processed by IT-S…

Estimation of Pyruvic acid in serum and saliva among healthy and potentially malignant disorder subjects – a stepping stone for cancer screening?

2014

Background: According to Warburg’s effect, the rate of glycolysis increases in cancerous cells. This will increase overall levels of pyruvic acid. The present on-going study was conducted to estimate the levels of pyruvic acid in saliva and serum in normal, oral PMD subjects. Material and Methods: A total of 50 subjects in healthy, PMD of the oral cavity individuals were selected based on clinical and histological criteria. Collected saliva and serum samples were subjected to pyruvic acid level estimation using biochemical analysis. Results: Of the 50 participants 25 (13: Males; 12: Females) & 25 (16: Males; 9: Females) were PMD group. Independent samples t test showed statistically signifi…

Photochemical sample treatment for extracts clean up in PCB analysis from sediments.

2013

Sample purification can be considered the most polluting step of the whole analytical process for PCBs determination in sediment samples. The use of photochemical sample treatment represents an alternative methodology for extracts clean up allowing for a reduction of the used amount of organic solvents. The first application of a photochemical sample treatment for the selective removal or reduction of organic substances interfering with PCBs analyses in sediments is reported. The method's efficiency and robustness were compared with currently used chromatographic purification. Quality parameters such as recovery, linearity and reproducibility were studied. The entire procedure was validated…

A new method for fluoride determination by using fluorophores and dyes anchored onto MCM-41

2002

A new colourimetric and fluorimetric method for fluoride determination in aqueous samples based on the specific reaction between fluoride and silica has been developed and applied on real samples. Descalzo Lopez, Ana Belen, adeslo@alumni.uv.es ; El Haskouri, Jamal, Jamal.Haskouri@uv.es ; Beltran Porter, Daniel, Daniel.Beltran@uv.es ; Amoros del Toro, Pedro Jose, Pedro.Amoros@uv.es

Revista electrónica de investigación y evaluación educativa

2014

Resumen basado en el de la publicación Título, resumen y palabras clave en inglés y español Se analiza el estatus del género existente en los equipos o consejos editoriales de las revistas científicas españolas de Educación. A priori, se indaga el estatus de la eminencia científica en el campo de la Educación; con el fin de detectar los posibles sesgos de género. Como análisis complementario se considera la nacionalidad o procedencia de los miembros de los consejos editoriales de las revistas de Educación. El hallazgo principal testimonia un fuerte sesgo contra las mujeres cuando éstas son consideradas editoras. Valencia ESP

2016

Abstract. Various geoscientific applications require a fast prediction of fracture permeability for an optimal workflow. Hence, the objective of the current study is to introduce and validate a practical method to characterize and approximate single flow in fractures under different stress conditions by using a core-flooding apparatus, in situ X-ray computed tomography (CT) scans and a finite-volume method solving the Navier–Stokes–Brinkman equations. The permeability of the fractured sandstone sample was measured stepwise during a loading–unloading cycle (0.7 to 22.1 MPa and back) to validate the numerical results. Simultaneously, the pressurized core sample was imaged with a medical X-ray…

From the Beehives: Identification and Comparison of Physicochemical Properties of Algerian Honey

2021

In this study, the authors aimed at characterizing 11 Algerian kinds of honey taken from various geographical locations (beehives located at Djelfa (Medjbara and Dzaira), Laghouat, Aflou, Medea, Tiaret, Sidi bel-Abbes, Tiaret, Ain-Safra, Mostaganem, El Bayadh, and Ghardïa). The authors investigated the physicochemical parameters of these honey samples, including density, water content, electrical conductivity, ash content, pH, hydroxymethylfurfural (HMF) content, free acidity, and color. The physicochemical parameters obtained were found to be within acceptable ranges according to the international standards (Codex Alimentarius) for 9 out of 11 analyzed samples: density 1.38–1.50 g/cm3 (the…