Use of nanomaterials in the pretreatment of water samples for environmental analysis

The challenge of providing clean drinking water is of enormous relevance in today’s human civilization, being essential for human consumption, but also for agriculture, livestock and several industrial applications. In addition to remediation strategies, the accurate monitoring of pollutants in water sup-plies, which most of the times are present at low concentrations, is a critical challenge. The usual low concentration of target analytes, the presence of in-terferents and the incompatibility of the sample matrix with instrumental techniques and detectors are the main reasons that renders sample preparation a relevant part of environmental monitoring strategies. The discovery and ap-plication of new nanomaterials allowed improvements on the pretreatment of water samples, with benefits in terms of speed, reliability and sensitivity in analysis. In this chapter, the use of nanomaterials in solid-phase extraction (SPE) protocols for water samples pretreatment for environmental monitoring is addressed. The most used nanomaterials, including metallic nanoparticles, metal organic frameworks, molecularly imprinted polymers, carbon-based nanomaterials, silica-based nanoparticles and nanocomposites are described, and their applications and advantages overviewed. Main gaps are identified and new directions on the field are suggested.publishe

Chapter 5 Analysis of Allele-Specific Gene Expression Using a Target- Oriented Tiling Microarray Assay

Advances in molecular and computational biology in recent years have led to the development or the improvement of methods for analyzing global gene expression. In most of these efforts, it is assumed that alleles of different origins contribute equally to the transcript pool. However, accumulating evidence suggests that many genes are not equally expressed from the paternal and maternal chromosomes. In addition to imprinting, the phenomenon of imbalanced allelic expression is widespread in heterozygous individuals. To distinguish transcript pools derived from different alleles present in the same organism, a number of methods have been developed. Here, we describe an oligonucleotide tiling microarray-based assay for analyzing allele-specific gene expression. Specifically targeting single-nucleotide polymorphisms, this twostep assay offers a high-throughput and multiplex method for detecting and quantifying unequal allelic expression that is readily applicable to many experimental systems

Two-Dimensional Perovskite (PEA)₂PbI₄ Two-Color Blue-Green Photodetector

Perovskite materials have been widely used to fabricate solar cells, laser diodes and other photodevices, owing to the advantage of high absorption coefficient, long carrier life and shallow defect energy levels. However, due to easy hydrolysis, it is difficult to fabricate perovskite micro-nano devices. Herein, we developed a water-free device fabrication technology and fabricated a two-dimensional (C6H5C2H4NH3)2PbI4 ((PEA)2PbI4) two-color blue-green light detector, which exhibits high detection performance under the illumination of two-color lasers (λ = 460 nm, 532 nm). Compared with bulk devices, the dark current of the fabricated devices (10−11 A) was reduced by 2 orders of magnitude. The peak responsivity and detectivity are about 1 A/W and 1011 Jones, respectively. The photodetection performance of the device is basically the same under the two-color lasers. Our results provide a new process to fabricate perovskite microelectronic devices, and the fabricated photodetector shows great application prospects in underwater detection, owing to the blue-green window existing in water

Equivalent stiffness prediction and global buckling analysis using refined analytical model of composite laminated box beam

The analytical model applicable to calculate the equivalent stiffnesses of composite box beam has been refined. The calculation of equivalent stiffness coefficients of composite laminated box beam is simplified and the connection between shear-deformable beam theory and classical laminate theory is established. The equivalent stiffness analytic formulas expressed by beam cross-section geometry and laminate stiffness coefficients are obtained. These analytical formulas are suitable for composite laminated box beam with circumferential uniform stiffness, and accounts for bending- transverse shear and torsiontensile coupling effect. The correctness and precision of refined analytical model is verified by test and finite element method, respectively. The influences of the lay-ups on the elastic coupling of composite structures and their causes are studied. The variation of the equivalent stiffnesses of the laminated box beams with different lay-ups is predicted. The global buckling analysis of composite laminated box beam considering the transverse shear deformation is carried out. The formula of the global buckling critical load is obtained combining with the theoretical formulas of equivalent stiffnesses. The influences of the lay-ups, shear deformation and slenderness ratio on the global buckling critical load are studied

All-Trans Retinoic Acid Improves the Effects of Bone Marrow-Derived Mesenchymal Stem Cells on the Treatment of Ankylosing Spondylitis: An In Vitro Study

Previous studies have demonstrated the immunosuppressive effects of both all-trans retinoic acid (ATRA) and mesenchymal stem cells (MSCs). The present study aimed to assess the immunoregulatory effects of ATRA on MSCs in the treatment of ankylosing spondylitis (AS). Bone marrow-derived MSCs from healthy donors were pretreated with ATRA and cocultured with CD3/28-activated peripheral blood mononuclear cells (PBMCs) derived from AS patients. Frequencies of Th17 and regulatory T (Treg) cells were analyzed using flow cytometry. The secretion and the mRNA level of key cytokines were measured with cytometric bead array and quantitative real-time PCR, respectively. ATRA pretreatment increased interleukin-6 (IL-6) secretion of MSCs. Th17 and Treg subset populations were increased and reduced by ATRA-pretreated MSCs, respectively. ATRA-pretreated MSCs significantly decreased not only the vital pathogenic cytokine in AS, tumor necrosis factor-α (TNF-α), but also AS-boosting factors interleukin-17 (IL-17A) and interferon-γ (IFN-γ). These results indicated that IL-6 may be a potential protective factor in AS and highlighted the promising role of ATRA in improving the efficacy of MSC-based treatment of AS

Experimental and Constitutive Model Study on Dynamic Mechanical Behavior of Metal Rubber under High-Speed Impact Loading

The development of lightweight, impact-resistant, and high energy-consuming materials is of great significance for improving the defense capabilities of military equipment. As a new type of damping material, metal rubber has demonstrated great potential for application in the field of impact protection. In this paper, the dynamic mechanical response of metal rubber under a high strain rate is studied, which provides a new idea for developing high-performance protective materials. The stress-strain curves, energy absorption performance, and wave transmission performance of metal rubber at various strain rates were investigated based on a split-Hopkinson pressure bar (SHPB) device. The dynamic stress-strain curve of metal rubber is divided into three stages: elastic stage, plastic stage, and failure stage. The optimal energy absorption efficiency is greater than 0.5, and the maximum value can reach 0.9. The wave transmittance is less than 0.01. The dynamic mechanical tests have proved that metal rubber has excellent energy absorption capacity and impact resistance property. A constitutive model based on Sherwood–Frost was established to predict the dynamic mechanical behavior of metal rubber. The results of comparison between the calculation and the experiment show that the constitutive model can accurately predict the dynamic mechanical performance of metal rubber

Analytical, Numerical, and Experimental Investigations on Transverse Bending Responses of CFRP Square Tube Filled with Aluminum Foam

In order to explore the transverse bending responses of carbon fiber-reinforced polymer (CFRP) square tubes filled with aluminum foam, the three-point bending tests were carried out on an INSTRON machine, the full-field deformation measurement was performed using a 3D-DIC test system, the numerical model was established by ABAQUS/Explicit, and the bending stiffness was calculated by the improved analytical model based on shear-deformable beam theory. The discrepancies of experimental data, numerical results, and analytical predictions were acceptable, which were within 5%. The failure modes and mechanical properties of the filled tubes were experimentally captured and numerically predicted. Due to the filling effect of aluminum foam, the ultimate load, bending stiffness, and energy absorption of the filled CFRP square tubes increased, comparing to those of the hollow CFRP square tubes. With the increase of the aluminum foam density, the ultimate load, bending stiffness, and energy absorption of the filled tubes increased, while the specific ultimate load, specific bending stiffness, and specific energy absorption decreased