Assessment of renal and hepatic dysfunction by co-exposure to toxic metals (Cd, Pb) and fluoride in people living nearby an industrial zone

Togo's phosphate processing plant at Kpeme discharges waste, containing Cd, Pb, and fluoride, into the sea and on the soil. Heavy metals toxicity on kidneys and the liver has been studied. However, fluoride toxicity on these organs remains to be investigated. The present study deals with the variation in renal and hepatic functioning parameters due to fluoride, Cd and Pb. Totally, 350 volunteers were recruited from five different localities around this phosphate processing plant for sample collection. Cd and Pb contents in blood samples were determined by spectrophotometry and fluoride by the titanium chloride method. Biochemical parameters were measured using Biolab kits. The pollutant contents were elevated in polluted areas where ASAT, ALAT, creatinine, and urea increased, and total protein decreased. Correlation and multivariate tests showed that fluoride is related to the various pathologies mentioned. PCA revealed that phosphate processing in Togo is a source of renal and hepatic toxicity.

Digital technology adoption scale in the blended learning context in higher education: Development, validation and testing of a specific tool

The main aim of the present study was to develop, validate and test an extended Technology Acceptance Model (TAM) that contributes to the overall understanding of students' intention to use digital tools in a blended learning context of higher education. The external bidimensional factor of familiarity with digital tools, which is not usually explained by the TAM, was included, and evaluated. Following a four-stage scale development technique, a seven-dimensional 25-item survey was developed, which includes two external correlated variables: familiarity with high-tech digital tools and familiarity with traditional digital tools, two mediator variables—computer anxiety, and perceived barriers, and three response variables, perceived usefulness, perceived ease of use and intention to use. The initial version of the survey was administered on 250 undergraduate students. Next, for another sample of 206 students, latent dimensions of the survey were tested using exploratory factor analysis. The structure of the survey was validated in two other subsequent stages with one sample of 262 responses of undergraduates and one of 310 responses of master's students from two different universities. All students who agreed to participate in research attended blended learning. The validity, reliability and invariance of the instrument were established by psychometric analyses. Collected data indicated that the survey has an adequate multifactorial structure that is reliable and invariant across degree levels. The scale is recommended for use in higher education studies targeting the promotion of blended learning and reduction of negative attitudes of learners toward digital instruments, supporting university professors to select their own efficient way to teach.

On-chip proteolytic digestion and analysis using "wrong-way-round" electrospray time-of-flight mass spectrometry

Rapid protein digestion and analysis using a hybrid microchip nanoelectrospray device and time-of-flight mass spectrometry detection are reported. The device consists of a planar glass chip with microfabricated channels coupled to a disposable nanospray emitter. Reactions between substrate and enzyme (trypsin), mixed off-chip and then immediately loaded into a sample reservoir on the device, are monitored in real time following the onset of electrospray. Protein cleavage products are determined at the optimum pH for generating tryptic fragments, directly from the digestion buffer using "wrong-way-round" electrospray, i.e., monitoring (MH)+ ions from basic solutions. Intense tryptic peptide ions are observed within a few minutes following sample loading on the microchip. Proteins were identified from low femtomole or even attomole quantities of analyte/spectrum using peptide mass fingerprinting, loading 0.1-2 pmol/microL of sample on the chip. The sequence coverage for analyzed proteins ranged from 70 to 95%. The rapid analysis of human hemoglobin is demonstrated using the technique.

Novel microfabricated device for electrokinetically induced pressure flow and electrospray ionization mass spectrometry

A novel microchip device for electrospray ionization has been fabricated and interfaced to a time-of-flight mass spectrometer. Fluid is electrokinetically transported through the chip to a fine fused-silica capillary inserted directly into a channel at the edge of the device. Electrospray is established at the tip of the capillary, which assures a stable, efficient spray. The electric potential necessary for electrospray generation and the voltage drop for electroosmotic pumping are supplied through an electrically permeable glass membrane contacting the fluidic channel holding the capillary. The membrane is fabricated on the microchip using standard photolithographic and wet chemical etching techniques. Performance relative to other microchip electrospray sources has been evaluated and the device tested for potential use as a platform for on-line electrophoretic detection. Sensitivity was found to be approximately three orders of magnitude better than spraying from the flat edge of the chip. The effect of the capillary on electroosmotic flow was examined both experimentally and theoretically.

Capillary electrophoresis--time-of-flight mass spectrometry of drugs of abuse

The use of capillary electrophoresis (CE) for the determination of drugs of abuse was explored. A commercial CE system was interfaced with a laboratory-built time-of-flight mass spectrometer (TOFMS) which was equipped with a high-speed data acquisition system to provide accurate monitoring of efficient separations. Ionization of the CE eluent was achieved with an electrospray ionization source. Standard mixtures and seized samples were analyzed either by direct infusion of the analyte solutions or after separation by CE. Detection at the low femtomole level was obtained using CE-TOFMS.