The thinner the better: SnO2 sheets that are five atomic layers thick are an efficient catalyst for the oxidation of CO (see picture). These sheets, which have 40 % surface atom occupancy and are ...fabricated by a scalable ethylenediamine‐assisted pathway, show remarkably improved catalytic performances compared to other SnO2 species, with the apparent activation energy lowered to 59.2 kJ mol−1 and the full‐conversion‐temperature lowered to 250 °C.
Gold nanoparticles and their arrays are some of the most studied nanomaterials, with promising applications in many fields such as electronics, optoelectronics, catalysis and biology. In order to ...protect bare gold nanoparticles from aggregation, to manipulate the optical, electronic and catalytic properties of the gold core, as well as to control interfacial properties, the gold nanoparticles are generally capped by an organic layer. Previous studies C.D. Bain, G.M. Whitesides, J. Am. Chem. Soc. 110 (1988) 3665–3666 have revealed that many phenomena (e.g., wetting, friction and adhesion), are sensitive to the top few angstroms of a surface. The interfacial properties of a gold surface derivatized with a self-assembled monolayer will thus be dictated by the functionalities present on the outer side of the monolayer. The synthesis, functionalization and surface structure of monolayer-protected gold nanoparticles have been intensively studied in recent times M.-C. Daniel, D. Astruc, Chem. Rev. 104 (2004) 293–346. In addition, the aggregation and dispersion of colloidal nanoparticles is one of the key issues related to their potential applications. The forces that govern the colloid stability of nanoparticle dispersions, and how to control them, have yet to be fully investigated. Here special attention has been paid to control of colloid stability using external stimuli. In this feature article, the following five areas are reviewed: synthesis and applications of nanostructured particles; formation and structure of self-assembled monolayer protected gold nanoparticles; colloid stability—DLVO and non-DLVO forces; photochemistry, photochromism and pyrimidine; and manipulation of colloid stability with external stimuli.
In this study, iron(III) extraction from acidic chloride solutions using undiluted trihexyltetradecylphosphonium chloride (Cyphos IL 101) was carried out in a liquid–liquid extraction process. ...The extraction behaviors under various HCl, chloride, and iron(III) concentrations; selectivity; and extraction isotherm of iron(III) were investigated. It was found that iron(III) was extracted fast and efficiently in a wide chloride concentration range. The highly selective separation of iron(III) from aluminum(III), calcium(II), magnesium(II), and potassium(I) in acidic chloride solutions was achieved with a separation factor of Fe(III) over Al(III) at 11 000 from a 3 M HCl solution. The maximum loading capacity of iron(III) reached 83.2 g·L–1 with a molar ratio of 0.91 for Fe(III)/Cyphos IL 101. Effective stripping of the loaded iron(III) was achieved with a 0.5 M H2SO4 solution. The iron-chloro complexes in both aqueous phase and Cyphos IL 101 phase were characterized using spectroscopic techniques. Ultraviolet–visible and Raman spectra confirmed that iron(III) formed a series of iron-chloro complexes in acidic chloride solutions, while present solely in the form of tetrachloroferrate complex (FeCl4−) in the Cyphos IL 101 phase. An extraction mechanism was proposed in which both FeCl3 ion association and FeCl4− anion exchange with the chloride anion of Cyphos IL 101 play the key role during iron(III) extraction.
The rank of contextuality Horodecki, Karol; Zhou, Jingfang; Stankiewicz, Maciej ...
New journal of physics,
07/2023, Letnik:
25, Številka:
7
Journal Article
Recenzirano
Odprti dostop
Abstract
Quantum contextuality is one of the most recognized resources in quantum communication and computing scenarios. We provide a new quantifier of this resource, the rank of contextuality (RC). ...We define RC as the minimum number of non-contextual behaviors that are needed to simulate a contextual behavior. We show that the logarithm of RC is a natural contextuality measure satisfying several properties considered in the spirit of the resource-theoretic approach. The properties include faithfulness, monotonicity, and additivity under tensor product. We also give examples of how to construct contextual behaviors with an arbitrary value of RC exhibiting a natural connection between this quantifier and the arboricity of an underlying hypergraph. We also discuss exemplary areas of research in which the new measure appears as a natural quantifier.
Agarose gels have been applied as templates for the formation of macroporous metal oxide structures. The preparation of the agarose template is extremely simple, and with variation of the agarose ...content, control over morphology is demonstrated: The average pore size decreases from 180 to 55 nm and the surface area increases from 238 to 271 m2 g-1 with increasing agarose content in the gel. The gelling temperature was also found to influence the final template morphology. Conducting sol−gel chemistry within the template structure followed by removal of the template by heating to 450 °C gives porous inorganic oxides. The technique has been demonstrated for the oxides of titanium, zirconium, niobium, and tin. The final morphology of the metal oxide is homogeneous and results from a coating of the agarose structure. The pore diameter decreased and the specific surface area of the titanium dioxide materials increased from 28 to 66 m2 g-1 as the agarose content in the template is increased from 0.5 to 5.0 wt%. The overall pore size and surface area are lower than the original gel due to shrinkage occurring with the sol−gel process, as well as crystallization and a loss of microporosity in the final material.
Atomically-thin sheet is a new class of two-dimensional materials that bring a wide range of extraordinary properties. However, the lack of intrinsic growth anisotropy makes the synthesis of ...atomically-thin non-layered materials a great challenge. Here, a versatile rapid-heating strategy is proposed and applied, in which the lamellar hybrid intermediate transforms into the clean and freestanding atomically-thin non-layered Cu2O sheet with 4 atomic thicknesses at 300°C in less than 8min. Taking advantage of efficient visible-light harvesting, improved carrier density, and fast interfacial charge transfer as well as facile electrochemical reactions, the ultrathin Cu2O sheets-based photoelectrode yields a photocurrent density up to 3.98mAcm−2, 36 times higher than that of bulk counterpart. Also, the photoelectrode reaches a visible-light-conversion-efficiency of 26.2% that is superior to most existing reports. The rapid-heating strategy guarantees the full exfoliation of lamellar hybrid intermediate into ultrathin Cu2O sheets with the removal of organic component, opening a new way to produce atomically-thin non-layered materials and holding great promise in the applications of visible-light photoelectrochemical water splitting.
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•A versatile rapid-heating strategy is proposed to synthesize atomically-thin non-layered Cu2O sheet with 4-atomic-thicknesses.•First-principles calculations reveal that atomically-thin Cu2O sheets possess increased density-of-states near Fermi level.•The atomically-thin Cu2O sheets exhibit 36 times higher visible-light conversion efficiency.•The high performances attribute to their ultrahigh fraction of surface atoms and increased density-of-states.
A proton-rich POM-type molybdenum phosphate K12Mo8O20(HPO4)8(PO4)Cl was successfully obtained. It crystallizes in a noncentrosymmetric tetragonal space group of P–4 (No. 81) with the unit cell ...parameters of a = 9.6580(4) Å, c = 14.2607(10) Å, and Z = 1. The occurrence and positions of the light element H in the structure are inferred from single-crystal X-ray diffraction and confirmed by DFT calculations. The hydrogen atoms are found to form hydroxyl bonds with O atoms from P(2)O4 and P(3)O4 constituting the Mo4P4O26H44– layers but are only weakly bound to the isolated P(3)O4 group through hydrogen bonds. The title compound presents a POM-type framework of corrugated Mo4P4O26H44– layers with four K+ ions and mixed ions (K4Cl3+ and isolated PO4 3–) orderly imbedding in the interlayer spaces with distances of 5.0396 (1) and 5.5966 (3) Å, respectively. The proton-rich nature and the structure feature were further verified by a series of experiments including 1H, 7Li, and 31P MAS NMR spectra, IR spectroscopy, and thermal analysis. Moreover, the weak bonding and large interlayer spaces make K+ and H+ ions susceptible to exchange with ions of Cs+, Ba2+, Zn2+, Pb2+, Cu2+, and Ni2+ commonly presented in chemical pollutants or nuclear wastes. In addition, the title compound shows a small second-harmonic generation signal, consistent with its noncentrosymmetric structure.
A proton-rich POM-type molybdenum phosphate K
Mo
O
(HPO
)
(PO
)Cl was successfully obtained. It crystallizes in a noncentrosymmetric tetragonal space group of
-4 (No. 81) with the unit cell ...parameters of
= 9.6580(4) Å,
= 14.2607(10) Å, and
= 1. The occurrence and positions of the light element H in the structure are inferred from single-crystal X-ray diffraction and confirmed by DFT calculations. The hydrogen atoms are found to form hydroxyl bonds with O atoms from P(2)O
and P(3)O
constituting the Mo
P
O
H
layers but are only weakly bound to the isolated P(3)O
group through hydrogen bonds. The title compound presents a POM-type framework of corrugated Mo
P
O
H
layers with four K
ions and mixed ions (K
Cl
and isolated PO
) orderly imbedding in the interlayer spaces with distances of 5.0396 (1) and 5.5966 (3) Å, respectively. The proton-rich nature and the structure feature were further verified by a series of experiments including
H,
Li, and
P MAS NMR spectra, IR spectroscopy, and thermal analysis. Moreover, the weak bonding and large interlayer spaces make K
and H
ions susceptible to exchange with ions of Cs
, Ba
, Zn
, Pb
, Cu
, and Ni
commonly presented in chemical pollutants or nuclear wastes. In addition, the title compound shows a small second-harmonic generation signal, consistent with its noncentrosymmetric structure.
Gut microbiota reportedly play a critical role in some autoimmune diseases by maintaining immune homeostasis. Only a few studies have examined the correlation between gut microbiota and the onset of ...primary immune thrombocytopenia (ITP), especially in children. The purpose of this study was to investigate changes in the composition and diversity of the fecal microbiota of children with ITP, as well as the correlation between such microbiota and the onset of ITP.
Twenty-five children newly diagnosed with ITP and 16 healthy volunteers (controls) were selected for the study. Fresh stool samples were collected to identify changes in the composition and diversity of gut microbiota as well as for potential correlation analysis.
In ITP patients, the phyla that were most frequently encountered were Firmicutes (54.3%), followed by Actinobacteria (19.79%), Bacteriodetes (16.06%), and Proteobacteria (8.75%). The phyla that were predominantly found in the controls were, Firmicutes (45.84%), Actinobacteria (40.15%), Bacteriodetes (3.42%), and Proteobacteria (10.23%). Compared with those of the controls, the proportions of Firmicutes and Bacteriodetes in the gut microbiota of ITP patients were increased while the proportions of Actinobacteria and Proteobacteria were decreased. Furthermore, gut microbiota in ITP patients varied by age group, showed specific changes in diversity, and were correlated with antiplatelet antibodies. IgG levels were significantly positively correlated with Bacteroides (
<0.01).
The gut microbiota of children with ITP are imbalanced, as shown by the increase in Bacteroidetes, which was positively correlated with IgG. Thus gut microbiota may contribute to ITP pathogenesis via IgG.
The clinical trial were registered and approved by the Institutional Review Committee of The Affiliated Huaian No.1 People's Hospital of Nanjing Medical University. Ethics number KY-2023-106-01.
