Particulate matter and ultrafine particles in urban air pollution and their effect on the nervous system.

According to the World Health Organization, both indoor and urban air pollution are responsible for the deaths of around 3.5 million people annually. During the last few decades, the interest in understanding the composition and health consequences of the complex mixture of polluted air has steadily increased. Today, after decades of detailed research, it is well-recognized that polluted air is a complex mixture containing not only gases (CO, NOx, and SO2) and volatile organic compounds but also suspended particles such as particulate matter (PM). PM comprises particles with sizes in the range of 30 to 2.5 µm (PM30, PM10, and PM2.5) and ultrafine particles (UFPs) (less than 0.1 µm, including nanoparticles). All these constituents have different chemical compositions, origins and health consequences. It has been observed that the concentration of PM and UFPs is high in urban areas with moderate traffic and increases in heavy traffic areas. There is evidence that inhaling PM derived from fossil fuel combustion is associated with a wide variety of harmful effects on human health, which are not solely associated with the respiratory system. There is accumulating evidence that the brains of urban inhabitants contain high concentrations of nanoparticles derived from combustion and there is both epidemiological and experimental evidence that this is correlated with the appearance of neurodegenerative human diseases. Neurological disorders, such as Alzheimer's and Parkinson's disease, multiple sclerosis, and cerebrovascular accidents, are among the main debilitating disorders of our time and their epidemiology can be classified as a public health emergency. Therefore, it is crucial to understand the pathophysiology and molecular mechanisms related to PM exposure, specifically to UFPs, present as pollutants in air, as well as their correlation with the development of neurodegenerative diseases. Furthermore, PM can enhance the transmission of airborne diseases and trigger inflammatory and immune responses, increasing the risk of health complications and mortality. Therefore, understanding the different levels of this issue is important to create and promote preventive actions by both the government and civilians to construct a strategic plan to treat and cope with the current and future epidemic of these types of disorders on a global scale.

Plasmonic Spherical Nanoparticles Coupled with Titania Nanotube Arrays Prepared by Anodization as Substrates for Surface-Enhanced Raman Spectroscopy Applications: A Review.

As surface-enhanced Raman spectroscopy (SERS) continues developing to be a powerful analytical tool for several probes, four important aspects to make it more accessible have to be addressed: low-cost, reproducibility, high sensibility, and recyclability. Titanium dioxide nanotubes (TiO2 NTs) prepared by anodization have attracted interest in this field because they can be used as safe solid supports to deposit metal nanoparticles to build SERS substrate nanoplatforms that meet these four desired aspects. TiO2 NTs can be easily prepared and, by varying different synthesis parameters, their dimensions and specific features of their morphology can be tuned allowing them to support metal nanoparticles of different sizes that can achieve a regular dispersion on their surface promoting high enhancement factors (EF) and reproducibility. Besides, the TiO2 photocatalytic properties enable the substrate's self-cleaning property for recyclability. In this review, we discuss the different methodological strategies that have been tested to achieve a high performance of the SERS substrates based on TiO2 NTs as solid support for the three main noble metal nanoparticles mainly studied for this purpose: Ag, Au, and Pt.

Simple in situ functionalization of carbon nanospheres.

Functionalized carbon nanospheres have been synthesized in situ via a facile chemical vapor deposition strategy, fabricated by the pyrolysis of toluene/ethanol mixtures at different percentages (0, 1, 2, 3, 4, and 5 wt% of ethanol). The as-grown nanospheres have been characterized using transmission electron microscopy, scanning electron microscopy, Raman and Fourier transform infrared spectroscopy, x-ray diffraction, nitrogen adsorption, zeta potential measurements and x-ray photoelectron spectroscopy. Results indicate that the incorporation of ethanol in the precursor solution reflected in the presence of oxygen and hydrogen functional groups, the highest functionalized nanospheres without compromising the morphology of the sample were yielded at 3 wt% concentration. These in situ added functional groups rendered the carbon nanostructures enhancedly dispersible and stable in water, avoiding post-synthesis and harsh chemicals processing; envisaging thus applications of the nanospheres in the biomedical field where hydrophilicity of the nanomaterials is mandatory.

Synthesis, Crystal Structure, and Computational Methods of Vanadium and Copper Compounds as Potential Drugs for Cancer Treatment.

Transition metal-based compounds have shown promising uses as therapeutic agents. Among their unique characteristics, these compounds are suitable for interaction with specific biological targets, making them important potential drugs to treat various diseases. Copper compounds, of which Casiopeinas® are an excellent example, have shown promising results as alternatives to current cancer therapies, in part because of their intercalative properties with DNA. Vanadium compounds have been extensively studied for their pharmacological properties and application, mostly in diabetes, although recently, there is a growing interest in testing their activity as anti-cancer agents. In the present work, two compounds, [Cu(Metf)(bipy)Cl]Cl·2H2O and [Cu(Impy)(Gly)(H2O)]VO3, were obtained and characterized by visible and FTIR spectroscopies, single-crystal X-ray diffraction, and theoretical methods. The structural and electronic properties of the compounds were calculated through the density functional theory (DFT) using the Austin-Frisch-Petersson functional with dispersion APFD, and the 6-311 + G(2d,p) basis set. Non-covalent interactions were analyzed using Hirshfeld surface analysis (HSA) and atom in molecules analysis (AIM). Additionally, docking analysis to test DNA/RNA interactions with the Casiopeina-like complexes were carried out. The compounds provide metals that can interact with critical biological targets. In addition, they show interesting non-covalent interactions that are responsible for their supramolecular arrangements.

Efficient anchoring of nanostructured cadmium selenide on different kinds of carbon nanotubes.

We report a method for the efficient anchoring of cadmium selenide (CdSe) nanoparticles on the surface of different types of multi-walled carbon nanotubes (purified, N-doped, O-doped and exfoliated). Characterization using different types of electron microscopies (SEM, STEM, and TEM), energy dispersive spectroscopy (EDS) and x-ray diffraction showed well anchored CdSe nanoparticles (NP) on the nanotube surfaces, NP shapes and sizes varied with temperature and other synthesis conditions, and formed with good yields. The method here reported does not require previous activation of the carbon nanotube surface by chemical functionalization, nor the use of organic solvents, and the reaction proceeded in aqueous solutions, making this process simpler and more environmentally friendly than others.

High yield and simple one-step production of carbon black nanoparticles from waste tires.

Carbon black (CB), a material consisting of finely divided particles, can be obtained by the partial combustion of heavy petroleum feedstock. The commercial preparation of CB nanoparticles require sophisticated equipment, chemical pre-treatment, and combination of complex separation and purification techniques. CB nanoparticles can also be recovered from scrubbed rubber, but yields are modest and the process is technically complex. Here, we report the development of a simple and inexpensive method for the preparation of CB nanoparticles from waste tires. Under optimal conditions, the yield of recovered CB nanoparticles (∼22 nm) was of approximately 81%; the nanomaterial presents good thermal stability and conductivity, and forms chain-like agglomerates; chemical composition analysis and solubility tests indicates that it is partly oxidized (C, 84.9%; S, 10.21%; O, 4.9%). The product was fully characterized by FTIR, Raman, TGA, BET, SEM and TEM. This preparation method could become a viable alternative to reduce the large amount of waste tires and decreasing their negative environmental impact, producing good quality CB nanoparticles useful for batteries, sensors, electronic devices, catalysis, pigments, concrete, and plastics, among many other applications.

Respiratory immune system and consequences due to particulate matter in air pollution / Sistema inmune respiratorio y consecuencias de contaminación aérea por materia particulada

The respiratory system is commonly known for being responsible for gaseous exchange. However, chronic exposure to air born pollution increases each year the number of asthma, chronic obstructive pulmonary disease (COPD), and lung cancer cases, which compels us to view the lung as a vulnerable organ due to the fact that because of its nature it enters in contact with substances present in the environment. Fortunately, the immune response mechanism acts locally in the lung in order to modulate the inflammatory response and to facilitate the clearance of inhaled pathogens, as well as volatile organic compounds (VOCs), metals, sulphur and nitrogen oxides, ozone and particulate matter (PM). Expanding our understanding of the molecular mechanisms underlying inflammation and pathology induced by airborne contaminant particles in the long term can help to develop strategies to reduce the risks of exposure to some of the most hazardous air pollutants, as well as to reduce the toxicity of nanomaterials and may also help to identify therapeutic targets to be used in the preventive treatment of susceptible groups.

El sistema respiratorio es comúnmente conocido por ocuparse del intercambio gaseoso; sin embargo, la exposición crónica a contaminantes del aire aumenta cada año el número de casos nuevos de asma, enfermedad pulmonar obstructiva crónica (EPOC) y cáncer de pulmón, lo que nos obliga a ver el pulmón como un órgano vulnerable, ya que por su naturaleza entra en contacto con sustancias presentes en el medio ambiente. Afortunadamente, el mecanismo de respuesta inmune actúa localmente en el pulmón para modular respuestas inflamatorias y para facilitar el aclaramiento de patógenos inhalados, así como de compuestos orgánicos volátiles (VOCs, por sus siglas en inglés), metales, óxidos de azufre y nitrógeno, ozono y materia particulada (PM, por sus siglas en inglés). Ampliar nuestra comprensión de los mecanismos moleculares que subyacen a la inflamación y a la patología inducida por partículas contaminantes en las vías respiratorias a largo plazo puede ayudar a desarrollar estrategias para reducir los riesgos de exposición a algunos de los contaminantes atmosféricos más peligrosos, así como a reducir la toxicidad de los nanomateriales y quizás pueda también ayudar a identificar objetivos terapéuticos que se puedan utilizar en el tratamiento preventivo de grupos susceptibles.

Carboxymethyl cellulose coated magnetic nanoparticles transport across a human lung microvascular endothelial cell model of the blood-brain barrier.

Sustained and safe delivery of therapeutic agents across the blood-brain barrier (BBB) is one of the major challenges for the treatment of neurological disorders as this barrier limits the ability of most drug molecules to reach the brain. Targeted delivery of the drugs used to treat these disorders could potentially offer a considerable reduction of the common side effects of their treatment. The preparation and characterization of carboxymethyl cellulose (CMC) coated magnetic nanoparticles (Fe3O4@CMC) is reported as an alternative that meets the need for novel therapies capable of crossing the BBB. In vitro assays were used to evaluate the ability of these polysaccharide coated biocompatible, water-soluble, magnetic nanoparticles to deliver drug therapy across a model of the BBB. As a drug model, dopamine hydrochloride loading and release profiles in physiological solution were determined using UV-Vis spectroscopy. Cell viability tests in Human Lung Microvascular Endothelial (HLMVE) cell cultures showed no significant cell death, morphological changes or alterations in mitochondrial function after 24 and 48 h of exposure to the nanoparticles. Evidence of nanoparticle interactions and nanoparticle uptake by the cell membrane was obtained by electron microscopy (SEM and TEM) analyses. Permeability through a BBB model (the transwell assay) was evaluated to assess the ability of Fe3O4@CMC nanoparticles to be transported across a densely packed HLMVE cell barrier. The results suggest that these nanoparticles can be useful drug transport and release systems for the design of novel pharmaceutical agents for brain therapy.

Trends in Materials Science for Ligament Reconstruction.

The number of ligament injuries increases every year and concomitantly the need for materials or systems that can reconstruct the ligament. Limitations imposed by autografts and allografts in ligament reconstruction together with the advances in materials science and biology have attracted a lot of interest for developing systems and materials for ligament replacement or reconstruction. This review intends to synthesize the major steps taken in the development of polymer-based materials for anterior cruciate ligament, their advantages and drawbacks and the results of different in vitro and in vivo tests. Until present, there is no successful polymer system for ligament reconstruction implanted in humans. The developing field of synthetic polymers for ligament reconstruction still has a lot of potential. In addition, several nano-structured materials, made of nanofibers or in the form of ceramic/polymeric nanocomposites, are attracting the interest of several groups due to their potential use as engineered scaffolds that mimic the native environment of cells, increasing the chances for tissue regeneration. Here, we review the last 15 years of literature in order to obtain a better understanding on the state-of-the-art that includes the usage of nano- and poly-meric materials for ligament reconstruction, and to draw perspectives on the future development of the field.

Heavy periodane.

The potential energy surface of the hypothetical NaMgAlSiPSCl system (heavy periodane) is exhaustively analyzed via the gradient embedded genetic algorithm (GEGA) in combination with density functional theory (DFT) computations. The electronegativity differences among the elements in both the second and third rows of the periodic table indicate that low-energy heavy periodane structures are obtained when highly electronegative and electropositive elements are bound together, but the global minimum of the heavy periodane system is completely different to its second-row analog (LiBeBCNOF).

2-Sulfanylidene-1,3-dithiolo[4,5-b]naphtho-[2,3-e][1,4]dithiine-5,10-dione.

The title mol-ecule, C(13)H(4)O(2)S(5), is folded by 47.83 (6)° along the S⋯S vector of the [1,4]dithiine six-membered ring, with the naphtho-quinone and [1,3]dithiole-2-thione moieties being nearly planar [largest deviations from least-squares planes = 0.028 (2) and 0.016 (1) Å, respectively]. This boat conformation is close to that observed in the analogous compound [Mendez-Rojas et al. (2001). J. Chem. Crystallogr.31, 17-28] including a 2-oxo group [folding angle: 42.3 (1)° at 213 (2) K]. Both compounds are indeed isomorphous, and the small difference in the folding angle probably results from the involvement of the thioxo group of the title compound in inter-molecular S⋯S contacts [3.5761 (13) Å]. In the crystal structure, mol-ecules are stacked in the [100] direction, with dithiole rings making π-π inter-actions. In a stack, alternating short and long separations are observed between the centroids of dithiole rings, 3.5254 (17) and 4.7010 (18) Å.

A helicoid ferrocene.

Here, we address the problem of stabilizing a new helicoid ferrocene. Of course, to obtain a helical complex, it is essential to design suitable organic ligands. The ligands should possess the correct symmetry to match the geometrical requirement of the metal center. We propose in silico a beautiful helix that consists of one polycyclic hydrocarbon composed of 10 fused cyclopentadiene rings bound on opposite sides of an iron atom. The nature of the metal-ligand interactions between Fe(2+) and the ligand was investigated with energy decomposition analysis. Our results provide strong evidence for the viability of the hitherto unknown helicoid ferrocene as a target for synthesis.

Planar tetracoordinate carbons in cyclic hydrocarbons.

[structure: see text] A series of cyclic hydrocarbons containing a planar tetracoordinate carbon atom is proposed. To rationalize the electronic factors contributing to the stability of these molecules, an analysis of the molecular orbitals and the induced magnetic field is presented.

Planar tetracoordinate carbon in extended systems.

A recently proposed system with a central planar tetracoordinate carbon linking two three-membered rings, C(5)(2-), lends itself to extension in one, two, and three dimensions. Our construction of potential realizations begins with an analysis of the electronic structure of C(5)(2-). Dimers such as C(10)Li(3-), C(10)Li(4), and a trimer C(15)Li(6) are then examined, and their geometries are optimized to find clues for ways the C(5)(2-) unit may polymerize in the presence of countercations. Coordination through the terminal carbons is favored in the oligomers and polymers; several electronically and structurally reasonable systems of the stoichiometry C(5)M(x) (M = Li, x = 2; M = Be, Pt, Zn, x = 1) emerge from band structure calculations and energetic considerations.