Search

Anaphylaxis; Food hypersensitivity; Latin America Anafilaxi; Hipersensibilitat alimentària; Amèrica Llatina Anafilaxia; Hipersensibilidad alimentaria; América Latina Background Recent data about clinical features, triggers and management of anaphylaxis in Latin America is lacking. Objective To provide updated and extended data on anaphylaxis in this region. Method An online questionnaire was used, with 67 allergy units involved from 12 Latin-American countries and Spain. Among data recorded, demographic information, clinical features, severity, triggering agents, and treatment were received. Results Eight hundred and seventeen anaphylactic reactions were recorded. No difference in severity, regardless of pre-existing allergy or asthma history was found. Drug induced anaphylaxis (DIA) was most frequent (40.6%), followed by food induced anaphylaxis (FIA) (32.9%) and venom induced anaphylaxis (VIA) (12%). FIA and VIA were more common in children-adolescents. Non-steroidal anti-inflammatory drugs (NSAIDs) and beta-lactam antibiotics (BLA) were the most frequent drugs involved. Milk (61.1% of FIA) and egg (15.4% of FIA) in children, and shellfish (25.5% of FIA), fresh fruits (14.2% of FIA), and fish (11.3% of FIA) in adults were the most common FIA triggers. Fire ants were the most frequent insect triggers, and they induced more severe reactions than triggers of FIA and DIA (p < 0.0001). Epinephrine was used in 43.8% of anaphylaxis episodes. After Emergency Department treatment, epinephrine was prescribed to 13% of patients. Conclusions Drugs (NSAIDs and BLA), foods (milk and egg in children and shellfish, fruits and fish in adults) and fire ants were the most common inducers of anaphylaxis. Epinephrine was used in less than half of the episodes emphasizing the urgent need to improve dissemination and implementation of anaphylaxis guidelines.

Reaction of the [HC(CMeNAr)2]SnCl (Ar = 2,4,6-Me3C6H2) with “GaI” in THF provided an unexpected transhalogenation reaction product [HC(CMeNAr)2]SnI. The crystal structure shows a tin(II) ion with a distorted tetrahedral pyramidal geometry. Theoretical calculations, using density functional theory (B3LYP), suggest the probable reaction mechanism for transhalogenation. The activation energy for moving from reactant ([HC(CMeNAr)2]SnCl to product [HC(CMeNAr)2]SnI) is only 10.2 kcal/mol. The chloride ion is displaced by the iodine ion, probably by the help of the gallium atom when it is coordinated to the chlorine atom. Keywords: Transhalogenation reaction, “GaI”, β-Diketiminate, X-ray, DFT

A short set of three new Schiff base chemosensors with high selectivity and sensitivity towards Al3+ over other metal cations in aqueous solution were developed and fully characterized. Compounds (E)-1-(( l -glutamine-imino)methyl)naphthalen-2-ol (A), (E)-1-((glucosamine-imino)methyl)naphthalen-2-ol (B), and (E)-3-hydroxy-4-(((2-hydroxynaphthalen-1-yl)methylene)amino)benzoic acid (C) exhibited a significant fluorescence enhancement in the presence of Al3+ over other competitive metal ions with a low detection limit of 0.103, 0.317 and 0.091 μM respectively, much lower than the WHO acceptable limit (0.05 mg/L or 1.85 μM of Al3+) in drinking water. The Schiff base C, shows high sensitivity in aqueous media (Limit of detection, LOD: 0.091 μM) and with a 38-fold (ϕ = 1.64% for Schiff free base; ϕ = 63.91% for Aluminium complex) fluorescence enhancement in the presence of Al3+. The theoretical research has enabled us to rationalize the behaviours of the three selective-sensors to Al3+ synthesized in this work. Based on the design, the amino acid Schiff bases (A) showed good solubility and compatibility with and without Al3+ and some fluorescent bioimaging (FBI) are reported in human epithelial cells Hs27.

A couple of luminescent organotin compounds derivated from ligands-ONO were obtained by multicomponent microwave assisted synthesis in short time (15 min) and good yields: ((E)-8, 8-8-diphenylbenzo[d] naphtho [1,2-h][1,3,6,2] dioxazastannonine (1) and (E)11, 13- di-tert-butyl, 8- diphenylbenzo [d] naphtho [1,2-h][1,3,6,2] dioxazastannonine (2)). Both compounds were fully characterized by NMR (1H, 13C, and 119Sn; 2D-NMR, HETCOR and COSY), UV–Vis, IR, and high-resolution mass spectrometry. The X-ray structures of two complexes demonstrate that the tin atoms adopt a bipyramidal trigonal geometry. The 119Sn NMR chemical shifts of the tin atom in the complexes are also consistent with the presence of pentacoordinate tin centers. The photophysical properties in solution and solid state, DFT, and voltammetry the two complexes have been determined.

A series of bi-nuclear fluorescent Boron Schiff bases (BOSCHIBAs) bis(1-B)Ph (5), bis(2-B)Ph (6), bis(3-B)Ph (7), and bis(4-B)Ph (8)) have been synthesized and the effects of temperature, pH, viscosity, and pressure on their fluorescence have been investigated. The compound 6 present a high response to various stimuli: shows 18 fold increase in fluorescence quantum yield with the increase in viscosity of the medium due to the restriction rotation at 90% glycerol. The boron compound 6 under basic conditions of pH the emission bands exhibited poor emission intensities and when the pH value is adjusted slightly below of neutral pH value, the fluorescence peak exhibited a hypsochromic shift from 421 to 400 nm. In state solid it compound was exposed to compression at 8t (t: metrics tons), its color changed from yellow to dark yellow and it was gradually lost its fluorescence property; this binuclear exhibit the property of reversible thermochromism. Compounds 5–8 have also been investigated using DFT. Computational work shows that the compound 6 has a free rotation about carbon-boron bond.

Multi-stimuli responsive fluorescent (MSRF) materials can change their photophysical properties upon application of two or more external stimulus such as temperature, mechanical stress, and acid-base vapors. These smart materials have received great attention due to their evident advantages in sensors, probes, displays, data recording, and bioimaging. The synthesis and characterization of (E)-4-hydroxy-N′-(2-hydroxy-4-methoxybenzylidene) benzohydrazide (1) and their two new organoboron compounds are described [4-(10-methoxy-2-phenylbenzo[h] [1,3,5,6,2]dioxadiazaboronin-4-yl)phenol (2) and 4,4′-(2,2′-(1,4-phenylene)bis(10-methoxybenzo[h] [1,3,5,6,2]dioxadiazaboronine-4,2-diyl))diphenol (3)]. The compounds were characterized by NMR (1H, 13C), UV/vis, fluorescence spectroscopy and high-resolution mass spectrometry (HRMS). The photophysical properties of organoboron were investigated; we found low fluorescence emission (Compound 2 ΦF: 0.89%, compound 3 ΦF: 0.93%) but in solid state showed interesting luminescent properties such as reversible thermochromism, piezochromism, vapochromism, and mechanochromism are reported.

The Environment-related parameters, including pH, oxygen level and viscosity play pivotal functions in controlling the physical, chemical and biological performance of local molecules. Irregular modification in these features would cause cellular malfunction can indicate the onset of severe diseases or become a hallmark of the incidence of severe diseases. Recently, luminescent molecules have drawn research interest from the field of fluorescent chemosensors, which have been designed to respond to such parameters and to map their variations in vitro/in vivo. In this review, we have screened a numerous literature of various responsive chemosensors related to fluorescent recognition of pH, oxygen level, and viscosity. The fluorescence-based bio-imaging (FBI) techniques play an important role in advancing the knowledge of cellular processes at the molecular level, both in vitro/in vivo and support medical biology and modern medicine. The mono-, dual and multi-stimuli responsive luminescent materials have the ability to detect changes in several clinically important factors like pH, oxygen level, and viscosity. In contrast, we have surveyed and summarized the literature regarding the use of fluorescence-based materials to detect changes in pH, oxygen level and highlight the low-cost green synthetic method of organometallic complexes, properties, and applications of the main group luminescence-based materials in order to get high yield.

Two new fluorescent organotin compounds bearing C3-symmetric Schiff base were synthesized by microwave irradiation via multicomponent reaction (3-MCR), in one pot in just 30 mins with excellent yields. Both tin complexes were fully characterized by NMR, IR, UV-vis, fluorescence spectroscopy, high-resolution mass spectrometry and by ciclyc voltametry. The δ 119Sn and 3J(1H,119Sn) of new organotin complexes 4 and 5 showed the high molecular symmetry and the trinuclearity through high resolution mass spectrometry. Both Sn-complexes are thermally stable up to 300°C. The small-wide angle X-ray scattering pattern in powder and the 2D monomolecular film by scanning tunneling microscopy (STM) of 5 showed a lamellar like assembly with dimension of 2.38 and 2.80 nm, respectively, meaning that molecules adopt a face-on arrangement, where molecules are flat-lying on the HOPG surface. Monolayer of 5 is mesoporous and rigid but covers large surface areas. The photophysical, electrochemical, and theoretical studies reveal that the three Sn-nuclei do not electronically interact. Since, both organotin complexes exhibit good quantum yield in solution (Φ 4: 52.4 % and 5: 51.7 %), with lifetimes in the range τ =∼3 ns, their emission properties are appealing for OLED applications.

In this paper, we report a series of Schiff bases synthesized by the condensation reaction between 2-hydroxy-1-naphthaldehyde with aniline derivatives as well as their further coordination with diphenylborinic acid for giving the corresponding boron Schiff bases (BOSCHIBAs) ( E )-N-((2-((di-phenylboryl)oxy)naphthalen-1-yl)methylene)pyridin-3-amine ( 1a ), ( E )-N-((2-((di-phenylboryl)oxy)naphthalen-1-yl)methylene)-2,6-di-methylaniline ( 2a ), and ( E )-N-((2-((di-phenylboryl)oxy)naphthalen-1-yl)methylene)-2,6-di-isopropylaniline ( 3a ). The resulting BOSCHIBAs were characterized by NMR ( 1 H, 13 C, and 11 B), FT-IR, and atmospheric pressure ionization time-of-flight mass spectrometry. BOSCHIBA 1a was structurally characterized by single-crystal. Structure analysis indicates that the boron atom adopts a tetrahedral molecular geometry into a six-membered ring with a half-chair conformation. BOSCHIBAs 1a - 3a and their ligands 1 - 3 exhibit relatively low quantum yields in a range from 1 to 3%. In a bioimaging study by using the BOSCHIBAs 2a , and 3a as fluorescent staining dyes, those materials showed enhanced features in terms of low cytotoxicity, simple synthesis, photostability, hydrolytic stability and specific staining for cytoplasm structures.

This paper describes an experimental study of microbial communities of three moving bed biofilm reactors (MBBR) inoculated with nitrifying cultures originated from environments with different salinity; freshwater, brackish (20‰) and seawater. All reactors were run until they operated at a conversion efficiency of >96%. The microbial communities were profiled using 454-pyrosequencing of 16S rRNA gene amplicons. Statistical analysis was used to investigate the differences in microbial community structure and distribution of the nitrifying populations with different salinity environments. Nonmetric multidimensional scaling analysis (NMDS) and the PERMANOVA test based on Bray-Curtis similarities revealed significantly different community structure in the three reactors. The brackish reactor showed lower diversity index than fresh and seawater reactors. Venn diagram showed that 60 and 78% of the total operational taxonomic units (OTUs) in the ammonia-oxidizing bacteria (AOB) and nitrite-oxidizing bacteria (NOB) guild, respectively, were unique OTUs for a given reactor. Similarity Percentages (SIMPER) analysis showed that two-thirds of the total difference in community structure between the reactors was explained by 10 OTUs, indicating that only a small number of OTUs play a numerically dominant role in the nitrification process. Acute toxicity of salt stress on ammonium and nitrite oxidizing activities showed distinctly different patterns, reaching 97% inhibition of the freshwater reactor for ammonium oxidation rate. In the brackish culture, inhibition was only observed at maximal level of salinity, 32‰. In the fully adapted seawater culture, higher activities were observed at 32‰ than at any of the lower salinities.

Here we report a green one-pot microwave-assisted synthesis of four push–pull organotin complexes derived from Schiff bases in good yields, which provides advancement over conventional method as it is simple, cost-effective and reproducible. All compounds were characterized by UV–Vis, TOF-HRMS, TGA-DTA, cyclic voltammetry, theoretical studies and compound 1 by X-ray single-crystal diffraction. Third-order nonlinear susceptibility χ(3) of complexes 1–4; ((E)-N′-(4-(diethylamino)-2-hydroxysalicylidine) nitrobenzohydrazidatediphenyl-tin (IV) (1), (E)-N′-(4-(diethylamino)-2-hydroxysalicylidine) nitrobenzohydrazidate di n-butyl-tin (IV) (2), ((E)-N′-(4-(methoxy)-2-hydroxysalicylidine) nitrobenzohydrazidate diphenyl-tin (IV) (3), (E)-N′-(4-(methoxy)-2-hydroxysalicylidine) nitrobenzohydrazidate di n-butyl-tin (IV) (4)) were measured via Maker-Fringes technique. In particular, compounds 1 and 2 display larger third-order nonlinearities than their methoxilated counterparts.

The expansion of alternative energy sources is one of the most vital goals all over the world to cut down the emission of greenhouse gases. Nowadays, the scientific community is facing the biggest challenge to innovate efficient photovoltaic cells, relatively high thermal stability and non-toxic environmental devices shortly. Currently, perovskites derived from lead, tin having high toxicity with negative environmental implications creating several obstacles to commercialize it. Thus, the key challenge connected with the conventional perovskite is the toxicity of lead and tin (Pb and Sn), which results negative impact on the environment. Currently, remarkable breakthroughs were found on non-toxic perovskites, keeping the major significant challenges in mind. We have focused on synthetic methods of non-toxic perovskites, toxicological information and fabrications of free-lead and tin perovskites (Mn, Sc, Ti, Fe, Cu, Ge, Nb, Ag, Sb, and Bi). This review data is of high impact on the commercialization of non-toxic perovskites in the future.

Synthetic methods for the formation of alkenes usually produce the E-alkene because it is more stable. However, in isomerization reaction (double bond migration) that takes place in α, β−unsaturated carbonyl compounds, when these carbonyl compounds are exposed to strong bases, furnish Z-alkenes highly stereoselective depending on the γ-substituent in the α, β-unsaturated carbonyl. This stereoselectivity can be attributed to the known Syn-effect. The synthetic value of this methodology is the achievement of chiral alcohol bearing an electron rich Z-alkene, as well as substituted, which was accomplished via removal of the oxazolidinone moiety under treatment with NaBH4, THF-H2O.

The multicomponent reaction of the 2-hydroxynaphthaldehyde with 2-aminophenol derivatives and their in situ complexation with diphenyltin oxide in acetonitrile provided, in high yield, the products: (((E)-12-nitro-8,8-diphenylbenzo[d]naphtho[1,2-h][1,3,6,2]dioxazastannonine and (E)-11-nitro-8,8-diphenylbenzo[d]naphtho[1,2-h][1,3,6,2]dioxazastannonine), where tin atom is pentacoordinated. The synthesis of their ligands ((E)-1-(((2-hydroxy-5-nitrophenyl)imino)methyl)naphthalen-2-ol and (E)-1-(((2-hydroxy-4-nitrophenyl)imino)methyl)naphthalen-2-ol) is also reported. The chemical structure of all the compounds has been established by nuclear magnetic resonance (1H, 13C, and 119Sn), infrared spectroscopy, and high resolution mass spectrometry. The 12-nitroanalogue was characterized by single-crystal X-ray structural analysis. The structure indicates that the backbone is essentially planar and the metal center resides in trigonal bipyramid geometry. The photophysical properties of the imines and those of the tin complexes were determined in solution exhibiting quantum yields around 4% with lifetimes in the range 10−10−10−11 s. In a preliminary study, a diode was fabricated by a spun film of the 12-nitroanalogue, the device showed intrinsic electroluminescence properties with a threshold voltage at 13 V, a high current density (500 mA/cm2) but a low luminance (0.03 cd/m2).

The trans-dichloro-trans-bis(dimethylsulfoxide)-trans-dimethyl-tin(IV) resulted from the reaction of dimethyl-tin(IV) dichloride and sodium sulfate in dimethylsulfoxide (DMSO). The tin compound was characterized by IR, NMR, FE-SEM, EDS, and single crystal X-ray diffraction studies. Suitable DMSO single crystals were obtained after 7 months by slow evaporation at room temperature. The crystal structure has a polymeric arrangement with eight-membered rings as a result of intermolecular coordination S O → Sn. The tin atom has an octahedral distorted geometry where the DMSO molecule is coordinated, and also has an infinite arrangement in 2D. Cytotoxicity against A431 cancer cells and MOLT4 leukemic cells and the DNA interaction of the organotin compound were determined. The organotin sulfate derivative showed low biological activity because of the polymeric structure and the saturated tin coordination capability.

The reaction of the tetramethylethylendiamine [(CH3)2NCH2CH2N(CH3)2] with SnCl2 in toluene provided the adduct dichloro-(1,2-bis(dimethylamino)ethane-N,N′)-tin(II) with a tetracoordinate metal center and pseudo-trigonal bipyramidal geometry with a stereochemically active unshared electron pair in its vertex. This compound was characterized by IR, NMR (1H, 13C, and 119Sn) and X-ray studies. The X-ray crystal structure of tin(II) complex shows just one of these three possible isomers. The relative energies of the three different isomers, HOMO and LUMO orbitals, and NMR chemical shifts were calculated, using the density functional theory in order to determine the coordination number. Keywords: Tin(II), TMEDA, X-ray, 119Sn NMR, DFT

A series of substituted 2-hydroxysalicylidine benzohydrazides were converted into their phenyl-boron complexes in good yields upon reaction with phenylboronic acid. All new compounds were characterized by NMR, UV, IR, spectroscopy and mass spectrometry. The X-ray structures of two complexes demonstrate that the boron atoms adopt a tetrahedral geometry. The 11B NMR chemical shifts of the boron atom in the complexes are also consistent with the presence of tetracoordinate boron centres. The photophysical properties of the free benzohydrazide ligands and their boron complexes have been determined and display quantum yields below 1% with lifetimes in the range 10−10–10−11 s.