Evaluation of deep eutectic solvents in the synthesis of molecularly imprinted fibers for the solid-phase microextraction of triazines in soil samples.

Nowadays, molecularly imprinted polymers (MIPs) are well established and are considered excellent materials for performing selective extractions. However, with the progressive implementation of the principles of green chemistry, it is necessary to find greener alternatives for both the synthesis and further use of MIPs in sample preparation. Accordingly, in the present work, different deep eutectic solvents (DES, both hydrophilic and hydrophobic), as an alternative to conventional organic solvents (i.e., toluene), were evaluated as porogens for the synthesis of imprinted fibers (monoliths), using fused silica capillaries as molds, for solid-phase microextraction (SPME). From this study, the polymer prepared with propazine (dummy template), methacrylic acid (monomer), ethylene glycol dimethacrylate (cross-linker), and a formic acid:L-menthol (1:1) DES (porogen) showed the best performance for selective rebinding of triazines. After optimization of the different variables involved in SPME, the new imprinted fibers were successfully applied to the extraction of target analytes (desisopropylatrazine, desethylatrazine, simazine, and atrazine) from soil sample extracts, providing relative recoveries ranging from 75.7 to 120.1%, reaching limits of detection within the range of 6.2-15.7 ng g-1, depending upon the analyte.

Modulation of central synapse remodeling after remote peripheral injuries by the CCL2-CCR2 axis and microglia.

Microglia-mediated synaptic plasticity after CNS injury varies depending on injury severity, but the mechanisms that adjust synaptic plasticity according to injury differences are largely unknown. This study investigates differential actions of microglia on essential spinal motor synaptic circuits following different kinds of nerve injuries. Following nerve transection, microglia and C-C chemokine receptor type 2 signaling permanently remove Ia axons and synapses from the ventral horn, degrading proprioceptive feedback during motor actions and abolishing stretch reflexes. However, Ia synapses and reflexes recover after milder injuries (nerve crush). These different outcomes are related to the length of microglia activation, being longer after nerve cuts, with slower motor-axon regeneration and extended expression of colony-stimulating factor type 1 in injured motoneurons. Prolonged microglia activation induces CCL2 expression, and Ia synapses recover after ccl2 is deleted from microglia. Thus, microglia Ia synapse removal requires the induction of specific microglia phenotypes modulated by nerve regeneration efficiencies. However, synapse preservation was not sufficient to restore the stretch-reflex function.

Recent advances and future trends in molecularly imprinted polymers-based sample preparation.

Molecular imprinting technology is a well-established technique for the obtainment of tailor-made polymers, so-called molecularly imprinted polymers, with a predetermined selectivity towards a target analyte or structurally related compounds. Accordingly, molecularly imprinted polymers are considered excellent materials for sample preparation providing unprecedented selectivity to analytical methods. However, the use of molecularly imprinted polymers in sample preparation still presents some shortcomings derived from the synthesis procedure itself limiting its general applicability. In this regard, molecularly imprinted polymers use to display binding sites heterogeneity and slow diffusion mass transfer of analytes to the imprinted sites affecting their overall performance. Besides, the performance of molecularly imprinted polymers in organic solvents is excellent, but their selective binding ability in aqueous media is considerably reduced. Accordingly, the present review pretends to provide an updated overview of the recent advances and trends of molecularly imprinted polymers-based extraction, focusing on those strategies proposed for the improvement of mass transfer and selective recognition in aqueous media. Besides, with the progressive implementation of Green Chemistry principles, the different steps and strategies for the preparation of molecularly imprinted polymers are reviewed from a green perspective.

Dynamic Feature Dataset for Ransomware Detection Using Machine Learning Algorithms.

Ransomware-related cyber-attacks have been on the rise over the last decade, disturbing organizations considerably. Developing new and better ways to detect this type of malware is necessary. This research applies dynamic analysis and machine learning to identify the ever-evolving ransomware signatures using selected dynamic features. Since most of the attributes are shared by diverse ransomware-affected samples, our study can be used for detecting current and even new variants of the threat. This research has the following objectives: (1) Execute experiments with encryptor and locker ransomware combined with goodware to generate JSON files with dynamic parameters using a sandbox. (2) Analyze and select the most relevant and non-redundant dynamic features for identifying encryptor and locker ransomware from goodware. (3) Generate and make public a dynamic features dataset that includes these selected parameters for samples of different artifacts. (4) Apply the dynamic feature dataset to obtain models with machine learning algorithms. Five platforms, 20 ransomware, and 20 goodware artifacts were evaluated. The final feature dataset is composed of 2000 registers of 50 characteristics each. This dataset allows for a machine learning detection with a 10-fold cross-evaluation with an average accuracy superior to 0.99 for gradient boosted regression trees, random forest, and neural networks.

Security in V2I Communications: A Systematic Literature Review.

Recently, the number of vehicles equipped with wireless connections has increased considerably. The impact of that growth in areas such as telecommunications, infotainment, and automatic driving is enormous. More and more drivers want to be part of a vehicular network, despite the implications or risks that, for instance, the openness of wireless communications, its dynamic topology, and its considerable size may bring. Undoubtedly, this trend is because of the benefits the vehicular network can offer. Generally, a vehicular network has two modes of communication (V2I and V2V). The advantage of V2I over V2V is roadside units' high computational and transmission power, which assures the functioning of early warning and driving guidance services. This paper aims to discover the principal vulnerabilities and challenges in V2I communications, the tools and methods to mitigate those vulnerabilities, the evaluation metrics to measure the effectiveness of those tools and methods, and based on those metrics, the methods or tools that provide the best results. Researchers have identified the non-resistance to attacks, the regular updating and exposure of keys, and the high dependence on certification authorities as main vulnerabilities. Thus, the authors found schemes resistant to attacks, authentication schemes, privacy protection models, and intrusion detection and prevention systems. Of the solutions for providing security analyzed in this review, the authors determined that most of them use metrics such as computational cost and communication overhead to measure their performance. Additionally, they determined that the solutions that use emerging technologies such as fog/edge/cloud computing present better results than the rest. Finally, they established that the principal challenge in V2I communication is to protect and dispose of a safe and reliable communication channel to avoid adversaries taking control of the medium.

Evaluation of 2-hydroxyethyl methacrylate as comonomer in the preparation of water-compatible molecularly imprinted polymers for triazinic herbicides.

In this work, the preparation and evaluation of water-compatible molecularly imprinted polymers for triazines using 2-hydroxyethyl methacrylate and methacrylic acid as comonomers is described. Four sets of molecularly imprinted and non-imprinted polymers for propazine were prepared at varying monomer molar ratios (from 4:0 to 1:3), and evaluated for the recognition of several triazines directly in aqueous media. The evaluation was performed by loading 1 mL of an aqueous solution containing 500 ng of each selected triazine, washing with 500 µL of acetonitrile, and eluting with 500 µL of methanol followed by 2 × 500 µL of a solution of methanol containing 10% of acetic acid. Final determinations were performed by high-performance liquid chromatography-ultraviolet detection. Improvement in molecular recognition of triazines in water was obtained on those molecularly imprinted polymers incorporating 2-hydroxyethyl methacrylate in 3:1 or 2:2 molar ratios, being the former selected as optimum providing recoveries for propazine up to 80%. A molecularly imprinted solid-phase extraction protocol was developed to ensure that triazines-selective recognition takes place inside selective binding sites in pure water media. Finally, the developed method was successfully applied to the determination of the selected triazines in environmental waters providing limits of detection from 0.16 and the 0.5 µg/L concentration range.

Infección por SARS-CoV-2 en neonatos menores de 28 días. Serie de casos multicéntrica / SARS-CoV-2 infection in infants aged 28 days and younger. A multicentre case series

No disponible

Preparation of Monolithic Fibers in Fused Silica Capillary Molds for Molecularly Imprinted Solid-Phase Microextraction.

In the last three decades, the use of molecularly imprinted polymers (MIPs) in sample preparation has continuously increased due to the high selectivity that they provide to this critical step. Of particular interest is the combination of molecular imprinting polymers and solid-phase microextraction (SPME) that allows the development of rapid and environmental friendly analytical methods, with high sensitivity and selectivity. The protocol herein presented describes a very simple strategy for the direct preparation of monolithic MIPs using silica capillaries as molds by the copolymerization of methacrylic acid and ethylene glycol dimethacrylate in the presence of propazine as template. The main factors affecting the polymer synthesis (e.g., porogen, monomer, cross-linker, polymerization mixture proportions, polymerization time, and fiber thickness) are described in detail. The proposed strategy is easy to perform in any laboratory without special equipment and allows precise control of the fiber thickness, overcoming this very common drawback in MIP-based fiber preparation.

Síndrome de Joubert / Joubert syndrome

El síndrome de Joubert es una enfermedad multisistémica poco frecuente. Se caracteriza por una malformación congénita del tronco cerebral e hipoplasia del vermis cerebeloso. Estas alteraciones provocan, entre otros, problemas respiratorios, hipotonía y retraso del desarrollo psicomotor. Puede asociar alteraciones a nivel renal, hepático u ocular, entre otros. No existe un tratamiento curativo de la enfermedad; por ello es importante un diagnóstico precoz, para ofrecer un seguimiento multidisciplinar y así poder mejorar el pronóstico y la calidad de vida de los pacientes y sus familias. (AU)

Joubert syndrome is a rare neurological disorder. It is characterized by the absence or underdevelopment of the cerebellar vermis and a malformed brain stem. These abnormalities cause signs and symptoms that include abnormal breathing patterns, hypotonia and development delay. It may associate kidney, liver or eye abnormalities. Treatment is supportive and depends on the symptoms in each person. This is why early diagnosis is so important, to offer a multidisciplinary strategy for improving the prognosis and quality of life. (AU)

Molecularly Imprinted Polymer-Quantum Dot Materials in Optical Sensors: An Overview of Their Synthesis and Applications.

In the last decades analytical methods have focused on the determination of target analytes at very low concentration levels. This has been accomplished through the use of traditional analytical methods that usually require high reagent consumption, expensive equipment and long pretreatment steps. Thus, there is a demand for simple, rapid, highly selective and user-friendly detection procedures. Quantum dots (QDs) are semiconductor fluorescent nanomaterials with unique optoelectronic properties that have shown great potential for the development of fluorescence probes. Besides, the combination of QDs with molecularly imprinted polymer (MIPs), synthetic materials with selective recognition, have been proposed as useful materials in the development of optical sensors. The resulting MIP-QDs optical sensors integrate the advantages of both techniques: the high sensitivity of QDs-based fluorescence sensors and the high selectivity of MIPs. This review gives a brief overview of the strategies for the synthesis of MIPs-QDs based optical sensors, highlighting the modifications in the synthesis procedure that improve the sensor performance. Finally, a revision of recent applications in sensing and bioimaging is presented.

Miniaturized analytical methods for determination of environmental contaminants of emerging concern - A review.

The determination of contaminants of emerging concern (CECs) in environmental samples has become a challenging and critical issue. The present work focuses on miniaturized analytical strategies reported in the literature for the determination of CECs. The first part of the review provides brief overview of CECs whose monitoring in environmental samples is of particular significance, namely personal care products, pharmaceuticals, endocrine disruptors, UV-filters, newly registered pesticides, illicit drugs, disinfection by-products, surfactants, high technology rare earth elements, and engineered nanomaterials. Besides, an overview of downsized sample preparation approaches reported in the literature for the determination of CECs in environmental samples is provided. Particularly, analytical methodologies involving microextraction approaches used for the enrichment of CECs are discussed. Both solid phase- and liquid phase-based microextraction techniques are highlighted devoting special attention to recently reported approaches. Special emphasis is placed on newly developed materials used for extraction purposes in microextraction techniques. In addition, recent contributions involving miniaturized analytical flow techniques for the determination of CECs are discussed. Besides, the strengths, weaknesses, opportunities and threats of point of need and portable devices have been identified and critically compared with chromatographic methods coupled to mass chromatography. Finally, challenging aspects regarding miniaturized analytical methods for determination of CECs are critically discussed.

EEG-Based BCI Emotion Recognition: A Survey.

Affecting computing is an artificial intelligence area of study that recognizes, interprets, processes, and simulates human affects. The user's emotional states can be sensed through electroencephalography (EEG)-based Brain Computer Interfaces (BCI) devices. Research in emotion recognition using these tools is a rapidly growing field with multiple inter-disciplinary applications. This article performs a survey of the pertinent scientific literature from 2015 to 2020. It presents trends and a comparative analysis of algorithm applications in new implementations from a computer science perspective. Our survey gives an overview of datasets, emotion elicitation methods, feature extraction and selection, classification algorithms, and performance evaluation. Lastly, we provide insights for future developments.

Fluorescent carbonaceous materials isolated from cigarette ashes for the determination of iron(iii) in water samples.

In the present work, ready-to-use fluorescent carbonaceous materials (CMs) were isolated from cigarette ashes by following a simple procedure based on the dispersion of ashes in water and subsequent filtration. The isolated raw material was characterized by fluorescence microscopy, Fourier transform infrared (FT-IR) spectroscopy, and dynamic light scattering (DLS) analysis. The isolated CMs displayed excitation-dependent fluorescence emission, which enables them to be used as a fluorescent probe. The developed fluorescent probe possesses high potential for sensitive and selective detection of Fe(iii) via a quenching mechanism. The decrease in fluorescence intensity was in linear relationship with the concentrations of Fe(iii) within the range of 0-89.6 µM. The fluorescent probe was successfully applied to the determination of Fe(iii) in tap and well waters with an average recovery of 87% with an excellent relative standard deviation (RSD) of 0.63%, regardless of the water sample analyzed. Besides, fluorescence variation in the presence of Fe(iii) was evaluated by analyzing red, green, and blue (RGB) channels of the fluorescence colors. Finally, the possibility of semi-quantitative determination of Fe(iii) in water by the naked eye using the proposed fluorescent probe was also evaluated.

Surface modified-magnetic nanoparticles by molecular imprinting for the dispersive solid-phase extraction of triazines from environmental waters.

Magnetic nanoparticles have been surface modified by molecular imprinting and evaluated as selective sorbents for the extraction of triazines from environmental waters. The use of propazine as template allowed us to synthesize a selective material able to simultaneously recognize and selective extract not only the template but also several other herbicides of the same family. A magnetic molecularly imprinted-based dispersive solid-phase extraction procedure was developed and fully optimized. Magnetic molecularly imprinted polymer particles can be easily collected and separated from liquid solvents and samples with the help of an external magnetic field, avoiding in that way any centrifugation or filtration steps, which represents a remarkable advantage over traditional procedures. Under optimum conditions, selective extraction of several triazines (cyanazine, simazine, atrazine, propazine, and terbutylazine) from environmental water samples was performed prior to final determination by high-performance liquid chromatography with diode-array detection. Recoveries for the studied triazines were within the range of 75.2-94.1%, with relative standard deviations lower than 11.3% (n = 3). The limits of detection were within 0.16-0.51 µg/L, depending upon the triazine and the type of sample analyzed.

Infección por SARS-CoV-2 en neonatos menores de 28 días. Serie de casos multicéntrica / SARS-CoV-2 infection in infants aged 28 days and younger. A multicentre case series

No disponible

The application of the supported liquid membrane and molecularly imprinted polymers as solid acceptor phase for selective extraction of biochanin A from urine.

An efficient sample clean-up and preconcentration procedure for phytoestrogens analysis in urine has been developed. It was based on a combination of solid phase extraction with hollow-fiber supported liquid membrane and molecularly imprinted beads (MIPs-HF-SLM-SPE). The molecularly imprinted polymers (MIPs) were synthesized by precipitation polymerization technique with biochanin A (BCA) as a template, giving narrowly dispersed microspheres with a regular shape. As the functional monomer, (dimethylamino)ethyl methacrylate (-DEM) turned out to be better than methacrylic acid (MAA) to get the best-imprinted effects. The MIPs used as sorbents in the MIPs-HF-SLM-SPE extraction process exhibited excellent binding selectivity for BCA, in comparison to non-imprinted polymers as well as its structural analogs (genistein and daidzein). Finally, the developed method was used to detect BCA in urine. Under optimal extraction conditions, the recovery of BCA in urine samples (using 4.5 mL sample spiked with 10 µg L-1) was over 41%, with a coefficient of variation (CV) < 6.6% (n = 5). The detection limit (LOD) and quantification limit (LOQ) for BCA analysis in urine were 0.41 and 1.36 µg L-1, respectively.

Molecularly imprinted polymer monolith containing magnetic nanoparticles for the stir-bar sorptive extraction of thiabendazole and carbendazim from orange samples.

In this work, a novel molecularly imprinted stir-bar was developed for the stir-bar sorptive extraction (SBSE) of thiabendazole (TBZ) and carbendazim (CBZ) from orange samples. Magnetic nanoparticles were surface modified with oleic acid and then encapsulated by a silica shell using a conventional sol-gel procedure. Subsequently, nanoparticles were functionalized with methacrylate functionalities by grafting onto the particles surface. Finally, the modified magnetic nanoparticles were entrapped in a polymer monolith synthetized by copolymerization with the imprinting polymerization mixture using a glass vial insert as a mold. Variables affecting the polymerization and rebinding conditions of target analytes were optimized. The uptake capacity for the template (TBZ) was evaluated as well as the cross-reactivity for the related compound CBZ by rebinding experiments. Finally, the proposed magnetic imprinted monolith was applied to the SBSE of TBZ and CBZ from orange sample extracts providing a remarkable clean-up ability. The calculated detection limit were 0.13 and 0.10 mg kg-1 for CBZ and TBZ respectively, low enough to satisfactory analysis of both compounds in orange samples according to current European Union regulations.