Hyaluronic Acid (HA)‐Based Silk Fibroin/Zinc Oxide Core–Shell Electrospun Dressing for Burn Wound Management

Burn injuries represent a major life‐threatening event that impacts the quality of life of patients, and places enormous demands on the global healthcare systems. This study introduces the fabrication and characterization of a novel wound dressing made of core–shell hyaluronic acid–silk fibroin/zinc oxide (ZO) nanofibers for treatment of burn injuries. The core–shell configuration enables loading ZO—an antibacterial agent—in the core of nanofibers, which in return improves the sustained release of the drug and maintains its bioactivity. Successful formation of core–shell nanofibers and loading of zinc oxide are confirmed by transmission electron microscopy, Fourier‐transform infrared spectroscopy, and energy dispersive X‐ray. The antibacterial activity of the dressings are examined against Escherichia coli and Staphylococcus aureus and it is shown that addition of ZO improves the antibacterial property of the dressing in a dose‐dependent fashion. However, in vitro cytotoxicity studies show that high concentration of ZO (>3 wt%) is toxic to the cells. In vivo studies indicate that the wound dressings loaded with ZO (3 wt%) substantially improves the wound healing procedure and significantly reduces the inflammatory response at the wound site. Overall, the dressing introduced herein holds great promise for the management of burn injuries.     

Imprinted polymer particles for selenium uptake: synthesis, characterization and analytical applications

This work reports the preparation of molecularly imprinted polymer (MIP) particles for selective extraction and determination of selenium ions from aqueous media. Polymerization was achieved in a glass tube containing SeO₂, o-phenylenediamine, 2-vinylpyridine (VP), ethyleneglycoldimethacrylate (EDMA), 2,2′-azobisisobutyronitrile (AIBN). The polymer block obtained was ground and sieved (55-75 μm) and the Se-o-phenylenediamine complex was removed from polymer particles by leaching with 2 M of HCl, which leaves a cavity in the polymer particles. The polymer particles both prior to and after leaching have been characterized by IR and thermogravimetric (TG) studies. The effect of different parameters, such as pH, extraction time, type and least amount of eluent for elution of complex from polymer were evaluated. Extraction efficiencies >99% were obtained by elution of the polymers with 15 mL of methanol-acetonitrile mixture (1:2, v/v). The limit of detection of the proposed method followed by hydride generation atomic absorption spectroscopy (HG-AAS) was found to be 3.3 μg L⁻¹ and a dynamic linear range (DLR) of 10-200 μg L⁻¹ was obtained. The relative standard deviations (R.S.D.s) at 30.0 μg L⁻¹ of Se were below than 8.1%. The influence of various cationic interferences on percent recovery of complex was studied. The method was applied to the recovery and determination of selenium in different real samples.     

Synthesis and characterization of new nitrate-bridged polymeric complexes of mercury(II) with phosphorus ylides

Reaction of phosphorus ylides of the type X-C₆H₄-COCHPAr₃ (X = Cl and NO₂; Ar = phenyl and p-tolyl) with Hg(NO₃)₂ · H₂O in equimolar ratios using methanol as solvent are reported. X-ray crystal structure analysis of [Hg(ClC₆H₄C(O)CHPPh₃)(NO₃)(μ-NO₃)]_n · (DMSO)_n shows that the 1:1 complex adopts the noncentrosymmetric polymeric structure in the solid state with NO^-₃ anion bridges. Variation of temperature or concentration in a ³¹P NMR study indicates that the disappearance of satellites, due to coupling to ¹⁹⁹Hg, occurs at increasing temperature or decreasing concentration.     

Quantum stochastic differential equation for squeezed light

In this paper, the quantum stochastic differential equation (QSDE) is derived which is based on explanatory for interaction of open quantum system with squeezed quantum noise. This equation describes the stochastic evolution of unitary operator and is used to compute the evolution of quantum observable and output field. Our QSDE has complete form with respect to previous QSDE for squeezed light, because it bears three fundamental quantum noises for its evolution and the scattering between quantum channels is included. Meanwhile, when squeezed noise reduces to vacuum noise, our QSDE reveals the famous Hudson-Parthasarathy QSDE. Our equations may have application for quantum network analysis of squeezed noise interferometer for gravitational wave detection.     

Three-Component,One-Pot Synthesis of 2,4,5-Trisubstituted Imidazoles Catalyzed by TiCl4-SiO2 Under Conventional Heating Conditions or Microwave Irradiation

In this study, silica-supported titanium tetrachloride was prepared and used as a novel catalyst for rapid and efficient synthesis of 2,4,5-trisubstituted imidazoles by a three-component, one-pot condensation of 1,2-diketones and aryl aldehydes in excellent yield under solvent-free conditions using conventional heating or microwave irradiation.

The effect of surface curvature of aluminum nitride nanotubes on the adsorption of NH3

Our main objectives are to address the following fundamental issues: (1) A density functional theory study on the structural and electronic properties of the zigzag single-walled aluminum nitride nanotubes (AlNNTs) with various diameters, using B3LYP/6-31G* level of theory. (2) An ONIOM study on the curvature effect of AlNNTs on the NH₃ adsorption process using B3LYP/6-31G* and semiempirical AM1 approaches. Furthermore, a potential energy surface is calculated for NH₃ moving toward AlNNT surface. In contrast to semiconducting carbon nanotubes (Louie, Top Appl Phys 80:113, 2001) our calculations confirmed that the HOMO?CLUMO energy gap of AlNNTs increases with an increase of the tube diameter. Additionally, we showed that HOMO/LUMO interaction between NH₃ and AlNNTs becomes stronger as the tube diameter decreases.     

Efficient Synthesis of Urea Derivatives via a Sequential One-Pot Nucleophilic Addition/Ugi Five-Component Reaction Under Solvent-Free Conditions

Urea polyfunctional derivatives were successfully synthesized via a one-pot, five-component nucleophilic addition/Ugi reaction sequence. Simplicity, solvent-free conditions, and good yields of products are advantages of this method.     

A computational study of water adsorption on boron nitride nanotube

The effect of water molecule adsorption on the surface of (5,0) zigzag boron nitride nanotube was studied by density functional theory calculations. Geometrical optimizations were carried out at the B3LYP/6-31+G* level of theory. Six different configurations of water molecule(s) adsorption process including monomer (1WB and 1WN), dimer (2WB, 2WNN, and 2WBN), and trimer (3WB) clusters were obtained. The strengths of interactions were analyzed by the equilibrium geometries, binding energies, and charge transfer. The natural bonding analysis was also performed to investigate electronic properties. The results reveal that the adsorption of water is more favorable as the water cluster size increases.     

Determination of cyanide using a chemiluminescence system composed of permanganate,rhodamine B,and gold nanoparticles

We describe a new chemiluminescence (CL) system based on the oxidation of rhodamine B (RhoB) with alkaline potassium permanganate in the presence of gold nanoparticles (Au-NPs) and anionic detergent sodium dodecyl sulfate. Free RhoB is weakly chemiluminescent when oxidized with permanganate at alkaline pH values. However, a remarkably strong enhancement of CL is observed in the presence of Au-NPs, probably due to a strong interaction between RhoB and the NPs. The possible mechanism was studied via recording the CL emission. It is also found that the intensity of CL gradually decreases in the presence of cyanide due to its interaction with the Au-NPs. The relation between the decreased CL intensity and cyanide concentration was exploited to develop a method for the determination of cyanide in the 0.01–0.5 μM concentration range, with a detection limit of 2.8 nM. The method was used to determine cyanide in spiked water, urine, and serum. Figure

Alkaline permanganate-rhodamine B-SDS CL reaction is dramatically enhanced by gold nanoparticles. Based on the inhibiting effect of cyanide on this system, a sensitive CL method was developed for its determination     

Structural,Theoretical, and Spectroscopic Study of Mercury(II) Complexes of two New Unsymmetric Phosphorus Ylides

Abstract

The reaction of Ph₂PCH₂PPh₂ (dppm) with 4-methylphenacyl bromide and 2-(bromoacetyl)naphthalene in chloroform produce the new phosphonium salts [Ph₂PCH₂PPh₂CH₂C(O)C₆H₄Me]Br (1) and [Ph₂PCH₂PPh₂CH₂C(O)C₁₀H₇]Br (2). Further, by reaction of the monophosphonium salts of dppm with the strong base Et₃N the corresponding bidentate phosphorus ylides, Ph₂PCH₂P(Ph)₂ = C(H)C(O)C₆H₄Me (3) and Ph₂PCH₂P(Ph)₂ = C(H)C(O)C₁₀H₇ (4) were obtained. The reaction of these ligands with mercury(II) halides in dry methanol led to the formation of the mononuclear complexes {HgX ₂[(Ph₂PCH₂PPh₂C(H)C(O)C₆H₄Me)]} [X = Cl (5), Br (6), and I (7)] and {HgX ₂[(Ph₂PCH₂PPh₂C(H)C(O)C₁₀H₇)]} [X = Cl (8), Br (9), and I (10)]. Characterization of the obtained compounds was performed by elemental analysis, IR, ¹H, ³¹P, and ¹³C NMR spectra. The structure of compounds 3 and 10 are unequivocally determined by single crystal X-ray diffraction techniques. X-ray analysis of 10 reveals the presence of mononuclear complex containing Hg atom in a distorted tetrahedral environment. In all complexes, the title ylides are coordinated through the ylidic carbon and the phosphine phosphorus. Computational studies on ligand 4 and complexes 8, 9, and 10 at DFT (B3LYP) level of theory are also reported. It was shown that the formation of P,C-coordinated 1+1 complex 10 is energetically more favored than corresponding P,P-coordinated 1+2 product.

[Supplemental materials are available for this article. Go to the publisher's online edition of Phosphorus, Sulfur, and Silicon and the Related Elements to view the following free supplemental files: Additional figures]