Allergologia et Immunopathologia
- The relationship between second-hand smoke and wheezing in infants from Córdoba, ArgentinaPublication date: Available online 16 October 2019Source: Allergologia et ImmunopathologiaAuthor(s): A. Teijeiro, M.N. Cuello, M.G. Raiden, R.E. Vieyra, D. Solé, P. Ellwood, R.M. GomezAbstractBackgroundWheezing constitutes a common respiratory symptom in children, and several risk factors have been associated with the prevalence of recurrent wheezing (RW) and its severity, especially viral respiratory infections and second-hand smoke (SHS) exposu
Angewandte Chemie International Edition
- Acyl Migration versus Epoxidation in Gold Catalysis: Facile, Switchable and Atom‐Economic Synthesis of Acylindoles and Quinoline DerivativesWe report a switchable synthesis of acylindoles and quinoline derivatives via gold‐catalyzed annulations of anthranils and ynamides. With an N,O‐ligand on a gold(III) catalyst α‐imino gold carbenes, in situ generated from anthranils, could undergo electrophilic attack to the aryl π‐bond followed by unexpected and highly selective 1,4‐ or 1,3‐acyl migrations to form 6‐acylindoles or 5‐acylindoles. With the JohnPhos ligand gold(I) carbenes experien
- Polymorphism of L‐TryptophanA new polymorph of L‐tryptophan has been prepared by crystallization from the gas phase, with structure determination carried out directly from powder XRD data augmented by periodic DFT‐D calculations. The new polymorph (denoted β) and the previously reported polymorph (denoted α) are both based on alternating hydrophilic and hydrophobic layers, but with substantially different hydrogen‐bonding arrangements. The β polymorph exhibits the energetic
- The electron spin as a chiral reagentIn contrast to the notion that enantiospecific chemical reactions require a chiral reagent molecule or catalyst, this work shows that enantioselective chemical transformations can be induced by the electron spin itself. As electrons are injected from a magnetized electrode into an adsorbed molecule, they have a distinct spin orientation relative to their velocity; i.e., they have a well‐defined helicity. Thus, it is possible to replace a conventi
- Chemoenzymatic posttranslational modification reactions for the synthesis of Ψ[CH2NH]‐containing peptidesThe Ψ[CH2NH] reduced amide bond is a peptide isostere widely used in the development of bioactive pseudopeptides. Here we report a method of chemoenzymatic posttranslational modification for the synthesis of Ψ[CH2NH]‐containing peptides converted from ribosomally expressed peptides. The posttranslational conversion composed of an enzymatic cyclodehydration and facile 2‐step chemical reduction achieves deoxygenation of a specific amide bond presen
- LiMII(IO3)3 (MII=Zn and Cd): Two Promising Nonlinear Optical Crystals Derived from a Tunable Structure Model of α‐LiIO33D structure: Two promising nonlinear optical (NLO) crystals LiMII(IO3)3 (MII=Zn and Cd) are rationally designed by the aliovalent substitution strategy. They achieve a suitable balance of excellent properties of larger second‐harmonic generation (SHG) response, wider energy band‐gap and optical transparency window, high large optical‐damage thresholds (LDT) and good stability. Abstract Excellent nonlinear optical materials simultaneously m
- Trapping and Reactivity of a Molecular Aluminium Oxide IonPolar opposites: A molecular aluminium oxide anion bearing a highly polarised Al−O bond is found to heterolytically cleave H2 at room temperature and ambient pressure. Abstract Aluminium oxides constitute an important class of inorganic compound that are widely exploited in the chemical industry as catalysts and catalyst supports. Due to the tendency for such systems to aggregate via Al‐O‐Al bridges, the synthesis of well‐defined, soluble,
- The Origin of Superhydrophobicity for Intrinsically Hydrophilic Metal Oxides: A Preferential O2 Adsorption Dominated by Oxygen VacanciesThe wettability of intrinsically hydrophilic rough‐textured metal oxides is related to oxygen‐vacancy‐dominated gas adsorption. Rough‐textured metal oxides show superhydrophobicity in oxygen but superhydrophilicity in nitrogen. Superhydrophobicity and superhydrophilicity can be achieved on the same metal oxide by tuning the proportion of planes defective in oxygen vacancies. Abstract The superhydrophobicity of intrinsically hydrophilic mate
- Controlling the Reactivity of the [P8W48O184]40− Inorganic Ring and Its Assembly into POMZite Inorganic Frameworks with Silver IonsSilver is the key: A polyoxometalate cluster based on the superlacunary heteropolyanion [P8W48O184]40− (abbreviated as {P8W48}) reacts with silver ions to self‐assemble three new all‐inorganic metal–oxide porous materials that expand the family of zeolitic polyoxometalate frameworks. The silver ions both enable reactions on the clusters as well as link them together. Abstract The construction of pure‐inorganic framework materials with well‐
- Metal‐Chelated Polymer Nanodiscs for NMR StudiesSpeeding up data acquisition: Design of a polymer nanodisc containing a DOTA chelator enables the utilization of the PRE effect in studies using lipid nanodiscs. This new technique can be applied to water‐soluble biomolecules such as G‐quadruplexes. Abstract Paramagnetic relaxation enhancement (PRE) is commonly used to speed up spin lattice relaxation time (T1) for rapid data acquisition in NMR structural studies. Consequently, there is sig
- Engineering of Ruthenium–Iron Oxide Colloidal Heterostructures: Improved Yields in CO2 Hydrogenation to HydrocarbonsRuthenium promotes reduction of iron oxide in ruthenium–iron oxide heterodimers by a proximal hydrogen spillover effect, leading to the formation of ruthenium–iron core–shell structures active for CO2 hydrogenation to hydrocarbons. Tuning the shell thickness leads to a fourfold increase in hydrocarbon yield. Abstract Catalytic CO2 reduction to fuels and chemicals is a major pursuit in reducing greenhouse gas emissions. One approach utilizes
- Exploring the Trans‐Cleavage Activity of CRISPR‐Cas12a (cpf1) for the Development of a Universal Electrochemical BiosensorAn electrochemical biosensor based on CRISPR‐Cas12a (cpf1), termed E‐CRISPR, is reported. Utilizing the trans‐cleavage activity of Cas12a, E‐CRISPR delivers a cost‐effective and portable biosensing platform for the detection of nucleic acids and proteins. Abstract An accurate, rapid, and cost‐effective biosensor for the quantification of disease biomarkers is vital for the development of early‐diagnostic point‐of‐care systems. The recent di
- Suk Bong Hong“If I could be any age I would be 20, the most unstable, but the most dynamic moment in my life. My favorite saying is: you can try …” Find out more about Suk Bong Hong in his Author Profile.
- Constrained Peptides with Fine‐Tuned Flexibility Inhibit NF‐Y Transcription Factor AssemblySet Me Free: A peptide‐derived inhibitor of the NF‐Y transcription factor was developed by constraining the conformation of an epitope through hydrocarbon stapling and then fine‐tuning its flexibility. In the initial set of constrained peptides, a non‐interacting α‐methyl group was observed to have a detrimental effect on complex stability. Adaption of the methylation pattern gave a peptide that inhibits transcription factor assembly and subseque
- Efficient Non‐dissociative Activation of Dinitrogen to Ammonia over Lithium‐Promoted Ruthenium Nanoparticles at Low PressureLithium treatment: Introduction of Li+ on Ru based catalysts can polarize and stabilize adsorbed dinitrogen on the metal surface, which facilitates the non‐dissociative pathway to produce ammonia under mild conditions. The Li–Ru catalysts are suitable for new green ammonia synthesis at lower pressure, and many times better than the commercial Fe counterparts. Abstract There is an exciting possibility to decentralize ammonia synthesis for fe
- Radial Hetero[5]catenanes: Peripheral Isomer Sequences of the Interlocked MacrocyclesLock on: A pair of radial [5]catenane isomers with different sequences of the peripheral macrocycles, β‐cyclodextrin and cucurbit[6]uril units, was obtained in high yield. Given the marked difference in binding strength and interlocking sequence of the peripheral macrocycles, interesting sequence‐dependent properties, characteristic of mechanically bonded macrocycles, were realized. Abstract A pair of radial [5]catenanes, with either an iso
- Trans‐selective Insertional Dihydroboration of a cis‐Diborene: Synthesis of Linear sp3‐sp2‐sp3‐Triboranes and Subsequent CationizationThe reaction of aryl‐ and amino(dihydro)boranes with dibora[2]ferrocenophane 1 leads to the formation 1,3‐ trans ‐dihydrotriboranes by formal hydrogenation and insertion of a borylene unit into the B=B bond. The aryltriborane derivatives undergo reversible photoisomerization to the cis ‐1,2‐ μ ‐H‐3‐hydrotriboranes, while hydride abstraction affords cationic triboranes, which represent the first doubly base‐stabilized B 3 H 4 + analog
- Reactions of Bromine Fluoride Dioxide, BrO2F,A reliable synthesis for unstable and highly reactive BrO 2 F is reported. This is converted into BrO 2 + SbF 6 ‐ , BrO 2 + AsF 6 ‐ , and BrO 2 + AsF 6 ‐ * BrO 2 F. The latter decomposes into the mixed valent Br 3 O 4 *Br 2 + AsF 6 ‐ with five, three, one, and zero valent bromine. BrO 2 + H(SO 3 CF 3 ) 2 ‐ is formed with HSO 3 CF 3 . Excess BrO 2 F yields mixed valent Br 3 O 6 + OSO 3 CF 3
- A novel meta‐stable pentavalent plutonium solid phase on the pathway from aqueous Pu(VI) to PuO2 nanoparticlesWe report here experimental evidence that the formation of PuO 2 nanoparticles from oxidized Pu(VI) under alkaline conditions proceeds through the formation of an intermediate Pu(V) solid phase, similar to NH 4 PuO 2 CO 3 , which is stable over a period of several months. For the first time, state‐of‐the‐art experiments at Pu M 4 and at L 3 absorption edges combined with theoretical calculations unambiguously allowed to determine the
- In‐situ Observation of Dynamic Galvanic Replacement Reactions in Twined Metallic Nanowires via Liquid Cell Transmission Electron MicroscopyGalvanic replacement is a versatile approach to prepare hollow nanostructures with controllable morphology and elemental composition for wide applications on catalysts and biomedicines. Towards a full understanding of galvanic replacement, the primary issue is to identify its fundamental mechanism. In this study, in‐situ liquid cell transmission electron microscopy was employed to monitor the dynamic reaction process and to explore the mechanism
- Lattice Distortion in Hollow Multi‐shelled Structures for Efficient Visible Light CO2 Reduction with SnS2/SnO2 JunctionPrecisely control the micro‐/nanostructures of nanomaterials, such as hollow multi‐shelled structure (HoMS), has shown its great advantages in various applications. In this paper, we moved forward our research direction to control the crystal structure of building blocks of HoMS, i.e., introducing the lattice distortion in HoMS, for the first time. The lattice distortion located at the nanoscale interface of SnS 2 /SnO 2 can provide additiona
- Tackling the World’s Phosphate Problem: Synthetic Humic Acids solubilize otherwise insoluble Phosphates for FertilizationArtificial humic acids (A‐HA) made from biomass in a hydrothermal process turn otherwise highly insoluble phosphates (e.g. iron phosphate as a model) into highly available phosphorus, which contributes to the fertility of soils and the coupled plant growth. A detailed electron microscopy study revealed etching of the primary iron phosphate crystals by the ‐COOH and phenolic groups of humic acids, but also illustrated the importance of the redox p
- In‐depth TEM Investigation on Structural Inhomogeneity within a Primary LixNi0.835Co0.15Al0.015O2 Particle: Origin of Capacity Decay during High‐rate DischargeThe structural stability of cathode materials during electrochemical reactions, in particular, under high‐rate discharge, is pertinent to the design and development of new electrode materials that can satisfy the stringent requirements of high energy and power density for electric vehicles. This study investigates the structural inhomogeneity that develops within a single LiNi 0.835 Co 0.15 Al 0.015 O 2 (NCA83) particle during a fast discharg
Δεν υπάρχουν σχόλια:
Δημοσίευση σχολίου