A lot of interesting and sophisticated examples of nanoparticle (NP) self-assembly (SA) are known. From both fundamental and technological standpoints, this field requires advancements in three ...principle directions: (a) understanding the mechanism and driving forces of three-dimensional (3D) SA with both nano- and microlevels of organization; (b) understanding disassembly/deconstruction processes; and (c) finding synthetic methods of assembly into continuous superstructures without insulating barriers. From this perspective, we investigated the formation of well-known star-like PbS superstructures and found a number of previously unknown or overlooked aspects that can advance the knowledge of NP self-assembly in these three directions. The primary one is that the formation of large seemingly monocrystalline PbS superstructures with multiple levels of octahedral symmetry can be explained only by SA of small octahedral NPs. We found five distinct periods in the formation PbS hyperbranched stars: (1) nucleation of early PbS NPs with an average diameter of 31 nm; (2) assembly into 100–500 nm octahedral mesocrystals; (3) assembly into 1000–2500 nm hyperbranched stars; (4) assembly and ionic recrystallization into six-arm rods accompanied by disappearance of fine nanoscale structure; (5) deconstruction into rods and cuboctahedral NPs. The switches in assembly patterns between the periods occur due to variable dominance of pattern-determining forces that include van der Waals and electrostatic (charge–charge, dipole–dipole, and polarization) interactions. The superstructure deconstruction is triggered by chemical changes in the deep eutectic solvent (DES) used as the media. PbS superstructures can be excellent models for fundamental studies of nanoscale organization and SA manufacturing of (opto)electronics and energy-harvesting devices which require organization of PbS components at multiple scales.
Cobalt oxides, CoO and Co3O4, were obtained from Co (II) acetate tetrahydrate. The thermal decomposition pathway of the starting product was followed by combining thermogravimetric analysis and in ...situ X-ray thermodiffraction. Under a nitrogen atmosphere, cobalt monoxide with Zn-blende and rocksalt polymorphs could be obtained almost as single phases at 330 and 400 °C, respectively. In addition to these oxides, a Co (II) oxyacetate, Co3O(CH3COO)4, was stabilized as an intermediate phase. Under an air atmosphere, Co3O4 (spinel structure type) was obtained as the only final product. The involved phases in this thermal decomposition process were characterized with scanning and transmission electron microscopy (SEM and TEM, respectively).
An easy, inexpensive urea-melt assisted route was designed for the synthesis of ∼10 nm-sized Ni/NiO nanoparticles (NPs). The method consists of the thermal decomposition of a urea-melted medium ...containing a Ni2+-salt and involves the olygomerization and self-combustion of the organic matrix and the formation of the Ni/NiO NPs within it in a two stepped process of Ni2+ reduction yielding Ni crystallization and subsequent inward oxidation. Control over the microstructural features of the NPs within three typical regimes was accomplished by means of the initial urea quantity. Type A samples (0.2 g urea/0.2908 g nickel nitrate) consists of NiO nanostructures which might contain dispersed Ni nuclei of a few atoms; B NPs (2 g urea/0.2908 g nickel nitrate) are made of proper small Ni cores, in the limit of the coherence length of XRD, surrounded by thick NiO shells, while C (20 g urea/0.2908 g nickel nitrate) NPs correspond to relative big Ni cores and thin NiO shells. Further control over the thickness of the NiO shell was achieved within each regime by means of the calcination time of the organic matrix, painting a whole palette of Nicore−NiOshell NPs. Magnetic characterization revealed large (for A and B) and common (C) shifts of the hysteresis loops, which were ascribed to the high disorder of the (A, B and C) NPs obtained by quenching as well as to exchange bias (EB) effects (B and C). A thorough characterization of the reaction pathway is reported.
The influence of particle size in both the structure and thermochromic behavior of 4H-SrMnO3 related perovskite is described. Microsized SrMnO3 suffers a structural transition from hexagonal ...(P63/mmc) to orthorhombic (C2221) symmetry at temperature close to 340 K. The orthorhombic distortion is due to the tilting of the corner-sharing Mn2O9 units building the 4H structural type. When temperature decreases, the distortion becomes sharper reaching its maximal degree at ∼125 K. These structural changes promote the modification of the electronic structure of orthorhombic SrMnO3 phase originating the observed color change. nano-SrMnO3 adopts the ideal 4H hexagonal structure at room temperature, the orthorhombic distortion being only detected at temperature below 170 K. A decrease in the orthorhombic distortion degree, compared to that observed in the microsample, may be the reason why a color change is not observed at low temperature (77 K).
BaFeCl0.13(2)O2.48(2) has been synthesized and studied. A proper tuning of the synthetic route has been designed to stabilize this compound as a single phase. The thermal stability and evolution, ...along with the magnetic and structural properties are reported here. The crystal structure has been refined from neutron powder diffraction data, and it is of the type (hhchc)2-10H. It is stable up to a temperature of 900 °C, where the composition reads BaFeCl0.13(2)O2.34(2). The study by electron microscopy shows that the crystal structure suffers no changes in the whole BaFeCl0.13(1)O3–y (2.34 ≤ 3 – y ≤ 2.48) compositional range. Refinement of the magnetic structure shows that the Fe is antiferromagneticaly ordered, with the magnetic moment parallel to the ab plane of the hexagonal structure. At higher temperature, a nonreversible phase transition into a (hchc)-4H structure type takes place with overall composition BaFeCl0.13(1)O2.26(1). Microstructural characterization shows that, in some crystals, this phase intergrows with a seemingly cubic related phase. Differences between these two crystalline phases reside in the chlorine content, which keeps constant through the phase transition for the former and disappears for the latter.
The main cause of serious ophthalmological injuries, includingviolent eye amputations in the context of so-called less lethalweapons, is the use of blunt objects, such as batons or extendablesticks ...and the use of kinetic energy projectiles (rubber bullets,pellets, foam projectiles or others). Such injuries in the contextof population control have been considered to constitute cruel,inhuman or degrading treatment or even torture when they arecarried out, intentionally or unintentionally, by State officials(or with their acquiescence or protection) and involve any of thepurposes contemplated in the Convention against Torture. Dueto their special characteristics, they constitute rights violationsthat entail unique difficulties and complexity from both a legaland forensic point of view. This paper addresses some of thesedifficulties with practical legal and forensic recommendations.It is structured in two parts: First, legal, where we considerlegal difficulties and provide suggestions on elements for obtainingevidence are given. Second, medico-psychological andforensic where we review the elements to be considered in theinterview, the medical and ophthalmological evaluation, andthe psychometric, psychological and psychiatric evaluation.
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•An innovative ternary composite, BiOCl-1/Bi12O17Cl2/Bi2O3, has been fabricated as a sustainable visible light-active photocatalyst.•Formation of an intimate heterojunction with high ...carrier separation efficiency and enhanced electronic and ionic conduction.•The photocatalytic activity of the ternary composite was tested on both single pollutants and binary mixtures.
The presence of pollutants in aquatic environments is causing severe health effects on both humans and animals. To address this issue, it has become crucial to develop more efficient and environmentally friendly photocatalysts for the removal of persistent pollutant mixtures from water. In this context, photocatalysts containing more than two bismuth-based materials have rarely been explored for water remediation. With this in mind, we propose an innovative ternary composite, BiOCl-1/Bi12O17Cl2/Bi2O3, as a potentially sustainable visible light-active photocatalyst. Firstly, bismuth oxychloride has been prepared in the presence of ionic liquid, leading to the formation of BiOCl-1 with highly reactive {110} facets. Subsequently, the construction of the ternary composite has been accomplished using a facile and soft hydrothermal approach. The as-prepared BiOCl-1/Bi12O17Cl2/Bi2O3 composite has been successfully used in degrading binary mixtures of contaminants (i.e. ciprofloxacin, methylparaben or methyl orange), achieving an improved visible-light photocatalytic activity compared to single BiOCl-1 and other previously reported bismuth-based photocatalysts. In addition, the photocatalytic mechanism and degradation pathways have been elucidated through scavenger and electrochemical experiments, as well as chromatography-mass spectrometry (LC-MS) analysis, respectively.
State violence against protesters McEvoy, Matthew; Corney, Neil; Parras, Marina ...
Torture,
05/2024, Letnik:
34, Številka:
1
Journal Article
Introduction: In recent years mass protest movements have taken to the streets in many countries across the world. Despite strong international and domestic legal protections for the right to freedom ...of peaceful assembly and other fundamental human rights, entire assemblies are frequently labelled violent and less lethal weapons are used to disperse them. Methods: This article examines the weapons often used by police against public assemblies. Focusing on striking weapons (batons), chemical irritants, kinetic impact projectiles and stun grenades, the article uses examples from various countries to illustrate how these weapons are being used and the associated human rights and health impacts. Results: Worrying trends identified include the use of dangerous or untested equipment, such as thermal foggers to deploy chemical irritants; the use of inherently abusive weapons, such as whips or sjamboks; and the increasing use of certain types of munitions, specifically indiscriminate kinetic impact projectiles. Discussion: The article seeks to support medical and legal professionals becoming more familiar with the weapons being used in the countries they practice in, the effects of those weapons, and clinical aspects in the presentation and care of those exposed.
In recent years mass protest movements have taken to the streets in many countries across the world. Despite strong international and domestic legal protections for the right to freedom of peaceful ...assembly and other fundamental human rights, entire assemblies are frequently labelled violent and less lethal weapons are used to disperse them.INTRODUCTIONIn recent years mass protest movements have taken to the streets in many countries across the world. Despite strong international and domestic legal protections for the right to freedom of peaceful assembly and other fundamental human rights, entire assemblies are frequently labelled violent and less lethal weapons are used to disperse them.This article examines the weapons often used by police against public assemblies. Focusing on striking weapons (batons), chemical irri-tants, kinetic impact projectiles and stun grenades, the article uses examples from various countries to illustrate how these weapons are being used and the associated human rights and health impacts. Re-sults: Worrying trends identified include the use of dangerous or untested equipment, such as thermal foggers to deploy chemical irritants; the use of inherently abusive weapons, such as whips or sjam-boks; and the increasing use of certain types of munitions, specifically indiscriminate kinetic impact projectiles.METHODSThis article examines the weapons often used by police against public assemblies. Focusing on striking weapons (batons), chemical irri-tants, kinetic impact projectiles and stun grenades, the article uses examples from various countries to illustrate how these weapons are being used and the associated human rights and health impacts. Re-sults: Worrying trends identified include the use of dangerous or untested equipment, such as thermal foggers to deploy chemical irritants; the use of inherently abusive weapons, such as whips or sjam-boks; and the increasing use of certain types of munitions, specifically indiscriminate kinetic impact projectiles.The article seeks to support medical and legal professionals becoming more familiar with the weapons being used in the countries they practice in, the effects of those weapons, and clinical aspects in the presentation and care of those exposed.DISCUSSIONThe article seeks to support medical and legal professionals becoming more familiar with the weapons being used in the countries they practice in, the effects of those weapons, and clinical aspects in the presentation and care of those exposed.
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