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

Water sorption properties of functionalized MIL-101(Cr)-X (X = -NH2, -SO3H, H, -CH3, -F) based composites as thermochemical heat storage materials

Thermochemical heat storage based on inorganic salt hydrates is a promising approach to relieve the heat energy supply and demand conflicts, but there exist lots of defects of pure salts when applied to the thermochemical. This paper attempted to use functionalized Metal-Organic Frameworks (MOFs) as the porous matrices to improve the heat storage performance of inorganic salt hydrates. A series of MOFs/CaCl2 composites based on MIL-101(Cr)-X (X = -NH2, -SO3H, H, -CH3, -F) were successfully synthesized and fully characterized by combining multiple techniques (i.e. powder X-ray diffraction, scanning electron microscopy, energy-dispersive X-ray analysis, N-2 adsorption-desorption, Fourier transform infrared spectroscopy, thermogravimetric and differential scanning calorimetry). The water sorption properties of the series of MOFs/CaCl2 composites were studied during the hydration process, and a continuous adsorption/desorption experiment was also performed to investigate the cycle stability of the MOFs/CaCl2 composites. The results show that the hydrophilic MOFs based composites have higher water sorption capacity (0.6 g(H2O)/g(sample) for MIL-101(Cr)-SO3H/CaCl2) accompanied with higher heat storage density (1274 J/g for MIL-101(Cr)-SO3H/CaCl2). Moreover, the series of MOFs all presented excellent cycle performance with little loss after continuous 17 adsorption/desorption cycles

Preparation of smart glass with superhydrophobic and thermochromic properties

The practical application of VO2 smart glass is usually restricted by poor thermochromic property and contaminant. In this study, the VOx/SiO2 composite films were fabricated using magnetron sputtering and sol-gel preparations. Compared with VOx-based films, the VOx/SiO2 composite films showed the superhydrophobic property, and its water contact angle was up to 165 degrees. At the same time, the VOx/SiO2 composite films retained the original excellent thermochromic property with solar regulation of 13.95%, luminous transmittance of 37.34% and the low phase transition temperature around 38 degrees C. This study provided guidance for the combined application of VO2 smart glass and superhydrophobic coating

Mechanically stable superhydrophobic surface on cement-based materials

Superhydrophobic surface is one of the important strategies for the application of water and ice resistance. In this study, we focused on the nano structure of hydration product itself of cement and superhydrophobic surface was created on hardened cement pastes (HCP) without any additive. The surface microstructures and surface chemical composition of ordinary HCP (O-HCP) and superhydrophobic HCP (S-HCP) both were characterized by SEM and FTIR respectively. The results of water absorption and anti-icing tests showed that the prepared S-HCP had lower water permeability, ice-adhesion strength and ice accumulation than O-HCP. Meanwhile, the surface of S-HCP remained superhydrophobic property after a series of mechanical performance tests and weather resistance tests, which indicated that the SCM has great application potential

MLR-1023 Treatment in Mice and Humans Induces a Thermogenic Program, and Menthol Potentiates the Effect

A glucose-lowering medication that acts by a different mechanism than metformin, or other approved diabetes medications, can supplement monotherapies when patients fail to meet blood glucose goals. We examined the actions underlying the effects of an insulin sensitizer, tolimidone (MLR-1023) and investigated its effects on body weight. Diet-induced obesity (CD1/ICR) and type 2 diabetes (db/db) mouse models were used to study the effect of MLR-1023 on metabolic outcomes and to explore its synergy with menthol. We also examined the efficacy of MLR-1023 alone in a clinical trial (NCT02317796), as well as in combination with menthol in human adipocytes. MLR-1023 produced weight loss in humans in four weeks, and in mice fed a high-fat diet it reduced weight gain and fat mass without affecting food intake. In human adipocytes from obese donors, the upregulation of Uncoupling Protein 1, Glucose (UCP)1, adiponectin, Glucose Transporter Type 4 (GLUT4), Adipose Triglyceride Lipase (ATGL), Carnitine palmitoyltransferase 1 beta (CPT1β), and Transient Receptor Potential Melastin (TRPM8) mRNA expression suggested the induction of thermogenesis. The TRPM8 agonist, menthol, potentiated the effect of MLR-1023 on the upregulation of genes for energy expenditure and insulin sensitivity in human adipocytes, and reduced fasting blood glucose in mice. The amplification of the thermogenic program by MLR-1023 and menthol in the absence of adrenergic activation will likely be well-tolerated, and bears investigation in a clinical trial

Highly Active Carbon Supported Pd–Ag Nanofacets Catalysts for Hydrogen Production from HCOOH

Hydrogen is regarded as a future sustainable and clean energy carrier. Formic acid is a safe and sustainable hydrogen storage medium with many advantages, including high hydrogen content, nontoxicity, and low cost. In this work, a series of highly active catalysts for hydrogen production from formic acid are successfully synthesized by controllably depositing Pd onto Ag nanoplates with different Ag nanofacets, such as Ag{111}, Ag{100}, and the nanofacet on hexagonal close packing Ag crystal (Ag­{hcp}). Then, the Pd–Ag nanoplate catalysts are supported on Vulcan XC-72 carbon black to prevent the aggregation of the catalysts. The research reveals that the high activity is attributed to the formation of Pd–Ag alloy nanofacets, such as Pd–Ag{111}, Pd–Ag{100}, and Pd–Ag­{hcp}. The activity order of these Pd-decorated Ag nanofacets is Pd–Ag­{hcp} > Pd–Ag{111} > Pd–Ag{100}. Particularly, the activity of Pd–Ag­{hcp} is up to an extremely high value, i.e., TOF_{hcp} = 19 000 ± 1630 h^–1 at 90 °C (lower limit value), which is more than 800 times higher than our previous quasi-spherical Pd–Ag alloy nanocatalyst. The initial activity of Pd–Ag­{hcp} even reaches (3.13 ± 0.19) × 10⁶ h^–1 at 90 °C. This research not only presents highly active catalysts for hydrogen generation but also shows that the facet on the hcp Ag crystal can act as a potentially highly active catalyst

Elevation of NR4A3 Expression and Its Possible Role in Modulating Insulin Expression in the Pancreatic Beta Cell

<div><p>Background</p><p>NR4A3/NOR-1 is a member of the NR4A orphan nuclear receptor subfamily, which contains early response genes that sense and respond to a variety of stimuli in the cellular environment. The role of NR4A3 in insulin expression in pancreatic beta cells remains unknown.</p><p>Methods</p><p>Dynamic changes in NR4A3 were examined in a pancreatic beta-cell line, MIN6, treated with thapsigargin (TG), palmitate (PA), tunicamycin (TM), and dithiothreitol (DTT), chemicals that produce cell stress and even apoptosis. We exploited virus infection techniques to induce expression of NR4A3 or three deletion mutants, and determined expression of insulin and insulin regulatory genes in MIN6 cells.</p><p>Results</p><p>TG and PA, two endoplasmic reticulum (ER) stress inducers, were able to induce unfolded protein response (UPR) activation and elevation of NR4A3 expression in MIN6 cells, whereas TM and DTT, two other ER stress inducers, were able to induce UPR activation but not NR4A3 elevation. MIN6 cells over-expressing NR4A3 protein after adenoviral infection exhibited reduced transcription of the insulin genes <i>Ins1</i> and <i>Ins2</i>, and reduced insulin protein secretion, which were negatively correlated with NR4A3 expression levels. Functional analysis of different deletion mutants of NR4A3 showed that deleting the activation domain AF1 or the DNA-binding domain abolished the down-regulation of insulin transcription by NR4A3 in MIN6 cells, indicating that this down-regulative role was closely related to the NR4A3 trans-activation activity. Over-expression of NR4A3 in MIN6 cells resulted in reduced mRNA transcription of the insulin positive-regulation genes, <i>Pdx1</i> and <i>NeuroD1</i>.</p><p>Conclusion</p><p>Some ER stress inducers, such as TG or PA, are able to elevate NR4A3 expression in MIN6 cells, while others, such as TM or DTT, are not. Over-expression of NR4A3 in MIN6 cells results in down-regulation of insulin gene transcription and insulin secretion. NR4A3 reduces insulin gene expression by modulating the expression of <i>Pdx1</i> and <i>NeuroD1</i>.</p></div

A model for possible role of NR4A3 in releasing pancreatic beta cells ER stress.

<p>Upon expression and activation of NR4A3 induced by factors such as long-chain free fatty acids (FFA) and thapsigargin (TG), which lead to ER stress, unfolded protein response (UPR) activation, and even apoptosis, this orphan nuclear receptor decreases insulin expression, which indirectly releases the burden of ER.</p

Possible roles of NR4A3 in modulating the expression of insulin genes in MIN6 cell lines.

<p>(A) Diagram of constructed wild-type and deletion forms of NR4A3 cDNA. (B) Verification by western blotting MIN6 cell lines stably over-expressing NR4A3 or its deletion forms. (C) mRNA levels of NR4A3 or two insulin genes (<i>Ins1</i> and <i>Ins2</i>) detected with reverse transcription PCR. Each image is representative of at least three experiments. (D) Semi-quantitative analyses of <i>Ins1</i> and <i>Ins2</i> mRNA levels normalized to beta actin in various stable cell lines (n = 5). ** <i>P</i><0.01 vs. the control cells. Data are representative of three clone lines. Con, cell line transfected with vector encoding GFP; N, cell line expressing the wild-type NR4A3; ΔA, cell line expressing the 2–288 amino acid (aa) deletion of AF1 (activation function-1 domain); ΔD, cell line expressing the 292–364 aa deletion of the DNA binding domain (DBD); ΔL, cell line expressing the 398–626 aa deletion of the ligand binding domain (LBD). The C terminal of all exogenous genes was HA-tagged to facilitate identification with western blotting.</p

Tunicamycin or dithiothreitol treatment resulted in UPR activation but no NR4A3 increase in MIN6 cells.

<p>(A, B) Relative mRNA levels of NR4A3 and <i>Chop</i>, respectively, determined with real-time quantitative PCR in response to different doses of tunicamycin (TM) in MIN6 cells. (D, E) Relative mRNA levels of NR4A3 and <i>Chop</i>, respectively, determined with real-time quantitative PCR in response to different doses of dithiothreitol (DTT) in MIN6 cells. (C, F) Spliced XBP1 (sXBP1) mRNA formation in response to different (C) TM or (D) DTT doses, respectively. Two forms of XBP1 (a UPR molecule) was detected with reverse transcription PCR. Data are shown as mean ± S.E. (n = 4). * p<0.05, ** p<0.01 vs. con (vehicle control group).</p