1,720,989 research outputs found
Innovative miniaturized approach by MicroNIR and chemometrics for the monitoring of the occupational exposure of workers
Full text linkInnovative preparation strategies for nanomaterial functionalization were proposed to provide novel tool to be used as drug delivery vectors for biomedical applications. In particular, three different carbon nanotubes were considered in this study such as the very small CNTs, the carboxylated CNTs (CNT-COOH) and the buckypapers and two polymers were used to study the functionalization. Different preparation procedures were investigated by thermogravimetric analysis (TGA), including the selection of the most performing polymer to be linked to the nanomaterial between PEI and PAMAM, the percentage of the polymer and the time of suspension. To simultaneously evaluate all these variables, an experimental design was planned and the recorded data were processed by chemometrics to identify the preparing procedure providing new nanomaterials able to conjugate microRNAs and to transfect efficiently endothelial cells
MicroNIR/chemometrics assessement of occupational exposure to hydroxyurea
Full text linkPortable Near Infrared spectroscopy (NIRs) coupled to chemometrics was investigated for the first time as a novel entirely on-site approach for occupational exposure monitoring in pharmaceutical field. Due to a significant increase in the number of patients receiving chemotherapy, the development of reliable, fast, and on-site analytical methods to assess the occupational exposure of workers in the manufacture of pharmaceutical products, has become more and more required. In this work, a fast, accurate, and sensitive detection of hydroxyurea, a cytotoxic antineoplastic agent commonly used in chemotherapy, was developed. Occupational exposure to antineoplastic agents was evaluated by collecting hydroxyurea on a membrane filter during routine drug manufacturing process. Spectra were acquired in the NIR region in reflectance mode by the means of a miniaturized NIR spectrometer coupled with chemometrics. This MicroNIR instrument is a very ultra-compact portable device with a particular geometry and optical resolution designed in such a manner that the reduction in size does not compromise the performances of the spectrometer. The developed method could detect up to 50 ng of hydroxyurea directly measured on the sampling filter membrane, irrespective of complexity and variability of the matrix; thus extending the applicability of miniaturized NIR instruments in pharmaceutical and biomedical analysis
The detection of cannabinoids in veterinary feeds by microNIR/chemometrics: A new analytical platform
No full textIn this work, the capabilities of a novel miniaturized and portable microNIR spectrometer were investigated in order to propose a practical and intelligible test allowing the rapid and easy screening of cannabinoids in veterinary feeds. In order to develop a predictive model that could identify and simultaneously quantify the residual amounts of cannabinoids, specimens from popular veterinary feeds were considered and spiked with increasing amounts of cannabidiol (CBD), Δ9-tetrahydrocannabinol (THC), and cannabigerol (CBG). Partial least squares discriminant analysis (PLS-DA) and partial least squares regression (PLSr) were applied for the simultaneous detection and quantification of cannabinoids. The results demonstrated that the microNIR/chemometric platform could statistically identify the presence of CBD, THC and CBG in the simulated samples containing cannabinoids from 0.001 to 0.01%w/w, with the accuracy and sensitivity of the official reference methods actually proposed. The method was checked against false positive and true positive responses, and the results proved to be those required for confirmatory analyses, permitting to provide a fast and accurate method for monitoring cannabinoids in veterinary feeds
Sol–gel synthesis and thermal behavior of bioactive ferrous citrate–silica hybrid materials
Full text linkImbalance of the iron level in the body causes several diseases. In particular, the low level of iron, during pregnancy, is
responsible for the iron deficiency anemia, and even of neurodegenerative diseases. Although the treatment of iron
deficiency anemia with oral iron supplements has been known, this problem still afflicts many people. The aim of this work
was the development of a system able to release ferrous ions in a controlled manner. Controlled drug release for medical
applications, indeed, appears to be a very interesting alternative to a systemic therapy because it is assurance of treatment
continuity and drug stability and optimizes drug absorption. For this purpose, ferrous citrate (Fe(II)C) was synthesized by a
redox reaction between iron powder and citric acid. Fourier transform infrared spectroscopy (FTIR), 1,10-phenanthroline
and sodium thiocyanate colorimetric assays confirmed that only Fe(II)C was obtained by redox reaction. Afterward,
obtained Fe(II)C was embedded within a SiO2 matrix in different mass percentage, by means of a sol–gel route. FTIR
spectroscopy and simultaneous thermogravimetry/first-order derivative of thermogravimetry were used to confirm the
Fe(II)C presence in the silica matrix and to investigate the thermal behavior of the sol–gel materials, respectively. The
bioactivity test carried out by soaking the synthesized drug delivery systems in a simulated body fluid showed that the
biological properties of the silica matrix are not modified by the presence of Fe(II)C
TGA/Chemometrics addressing innovative preparation strategies for functionalized carbon nanotubes
Full text linkIn this work, functionalized carbon nanotubes (CNTs) using two polyamine polymers, polyethyleneimine (PEI) and polyamidoamine dendrimer (PAMAM), were investigated by thermal analysis in order to address preparation strategies to obtain low cytotoxic compounds with the ability to conjugate microRNAs and, at the same time, to transfect efficiently endothelial cells. Thermogravimetric analysis (TGA) was coupled to chemometrics as a novel analytical strategy to characterize functionalized CNTs from different preparation conditions. In particular, two starting materials were considered: very small CNTs and carboxylated CNTs (CNT-COOH) in order to examine the affinity with polymers. Chemometrics permitted to compare results from TGA and to investigate the effect of a number of factors affecting the synthesis of coated nanotubes including a different amount of involved polymer and the time required for the suspension for a satisfactory and reproducible preparation procedure. The results demonstrated the effectiveness of TGA as a tool able to address synthesis of coated CNTs to be employed as efficient drug delivery vectors in biomedical applications. (C) 2020 Xi'an Jiaotong University. Production and hosting by Elsevier B.V
MicroNIR/Chemometrics: a new analytical platform for fast and accurate detection of Δ9-Tetrahydrocannabinol (THC) in oral fluids
No full textBackground: Δ9-Tetrahydrocannabinol (THC) is already considered one of the most addictive substances since an increasing number of consumers/abusers of THC and THC based products are observed worldwide. In this work, the capabilities of a novel miniaturized and portable MicroNIR spectrometer were investigated in order to propose a practical and intelligible test allowing the rapid and easy screening of Δ9-Tetrahydrocannabinol (THC) oral fluids without any pretreatment. Methods: Specimens from volunteers were collected in order to consider any sources of variability in the spectral response and spiked with increasing amount of THC in order to realize predictive models to be used in real cases. Partial Least Square-Discriminant Analysis (PLS-DA) and Partial Least Square regression (PLSr) for the simultaneously detection and quantification of THC, were applied to baseline corrected spectra pre-treated by first derivative transform. Results: Results demonstrated that MicroNIR/Chemometric platform is statistically able to identify THC abuse in simulated oral fluid samples containing THC from 10 to 100 ng/ml, with a precision and a sensitivity of about 1.51% and 0.1% respectively. Conclusions: The coupling MicroNIR/Chemometrics permits to simplify THC abuse monitoring for roadside drug testing or workplace surveillance and provides the rapid interpretation of results, as once the model is assessed, it can be used to process real samples in a “click-on” device
Development of a "single-click" analytical platform for the detection of cannabinoids in hemp seed oil
No full textIn this work, an innovative screening platform is developed and validated for the on site detection of cannabinoids in hemp seed oil, for food safety control of commercial products. The novelty of this completely automated tool consists of a miniaturized NIR spectrometer operating in a wireless mode that permits processing samples in a rapid and accurate way and to obtain in a single click the early detection of a residual amount of cannabinoids in oil, including cannabidiol (CBD), the psychoactive Δ9-tetrahydrocannabinol (THC) and the Δ9-tetrahydrocannabinolic acid (THCA). Simulated samples were realized to instruct the platform and prediction models were developed by chemometric analysis of the NIR spectra using partial least square regression algorithms. Once calibrated, the platform was used to predict samples acquired in the market and on websites. Validation of the system was achieved by comparing results with those obtained from GC-MS analyses and a good correlation was observed
Hemorheological Alterations and Oxidative Damage in Sickle Cell Anemia
No full textSickle cell anemia (SCA) is the most common hereditary disorder of hemoglobin (Hb) characterized by a mutation in the β globin gene, which leads to synthesis of HbS a hemoglobin which, under hypoxic conditions, gels and leading to the sickling of the red blood cells (RBC). The dehydration of the RBC increases the concentration of the intracellular Hb with an increase in the internal viscosity and consequently a decrease in the erythrocyte deformability. Sickle red blood cells due to their difficulty to flow through the microcirculation cause frequent vaso-occlusive episodes, tissue ischemia, and infarctions. Moreover, the reduced RBC deformability causes cell fragility leading to hemolysis and recently a key role of hemolysis and oxidative stress in the development of vascular dysfunction has been demonstrated. The aim of this study was to evaluate the hemorheological profiles of patients with SCA in order to point out new indices of vascular impairment, and to characterize the membrane oxidative damage of sickled RBC. Blood viscosities, erythrocyte aggregation, and viscoelastic profiles of SCA patients were determined, and the RBC oxidative damage was investigated by comparing metabolic capability and RBC membrane proteins from SCA patients with and without transfusion dependence. The hemorheological profile of SCA subjects demonstrated high blood viscosity, increased RBC aggregation, and decreased RBC deformability. These impaired flow properties were associated with RBC membrane protein oxidation, with degradation of spectrin and increased membrane-bound globin. The comparison between SCA patients with and without transfusion dependence showed metabolic and structural RBC oxidative damage significantly different
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe 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
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