Search

The purpose of this study was to enhance the antimicrobial activity of bagasse paper by coating the paper with bismuth oxide (Bi 2 O 3 ) and using it to accelerate the process of wound healing. Paper sheets were prepared from sugarcane waste (bagasse). First, the paper sheets were coated with different Bi 2 O 3 concentrations to improve the antimicrobial activity of the paper. After that, the paper sheets were allowed to dry in an oven at 50 °C for 3 h. Then, in vitro antimicrobial activity was evaluated against different microbial species, including Gram-negative bacteria (i.e., Klebsiella pneumonia, Escherichia coli) and Gram-positive bacteria (i.e., Staphylococcus aureus, Streptococcus pyogenes). The obtained results showed that the paper coated with 25% and 100% Bi 2 O 3 had activity against all models of bacteria; however, the paper coated with 100% Bi 2 O 3 composite had the strongest inhibitory effect. Then, bagasse paper was coated with 100% Bi 2 O 3 and different antibiotics, to investigate their wound-healing potency in a wounded rat model for 14 days. Moreover, the paper coated with 100% Bi 2 O 3 inhibited the cellular migration in vitro. Conclusively, coating paper with Bi 2 O 3 enhances the wound-healing potential when applied to wounds. This impact could be ascribed to Bi 2 O 3 's broad antibacterial activity, which reduced infection and accelerated the healing process.

A new series of N'-substituted benzylidene-2-(4-oxo-2-phenyl-1,4-dihydroquinazolin-3(2H)-yl)acetohydrazide ( 5a-5h ) has been synthesized, characterized by FT-IR, NMR spectroscopy and mass spectrometry and tested against human monoamine oxidase (MAO) A and B. Only (4-hydroxy-3-methoxybenzylidene) substituted compounds gave submicromolar inhibition of MAO-A and MAO-B. Changing the phenyl substituent to methyl on the unsaturated quinazoline ring ( 12a-12d ) decreased inhibition, but a less flexible linker ( 14a-14d ) resulted in selective micromolar inhibition of hMAO-B providing insight for ongoing design., Competing Interests: There are no conflicts to declare., (© 2020 The Authors.)

This study was conducted to determine what effects nanoparticles (NPs) like TiO 2 , ZnO, and Ag may pose on natural attenuation processes of petroleum hydrocarbons in contaminated soils. The solid NPs used were identified using x-ray diffraction technique and their average size was certified as 18.2, 16.9, and 18.3 nm for Ag-NPs, ZnO-NPs, and TiO 2 -NPs, respectively. NPs in soil microcosms behave differently where it was dissolved as in case of Ag-NPs, partially dissolved as in ZnO-NPs or changed into other crystalline phase as in TiO 2 -NPs. In this investigation, catabolic gene encoding catechol 2,3 dioxygenase (C23DO) was selected specifically as biomarker for monitoring hydrocarbon biodegradation potential by measuring its transcripts by RT-qPCR. TiO 2 -NPs amended microcosms showed almost no change in C23DO expression profile or bacterial community which were dominated by Bacillus sp., Mycobacterium sp., Microbacterium sp., Clostridium sp., beside uncultured bacteria, including uncultured proteobacteria, Thauera sp. and Clostridia. XRD pattern suggested that TiO 2 -NPs in microcosms were changed into other non-inhibitory crystalline phase, consequently, showing the maximum degradation profile for most low molecular weight oil fractions and partially for the high molecular weight ones. Increasing ZnO-NPs concentration in microcosms resulted in a reduction in the expression of C23DO with a concomitant slight deteriorative effect on bacterial populations ending up with elimination of Clostridium sp., Thauera sp., and uncultured proteobacteria. The oil-degradation efficiency was reduced compared to TiO 2 -NPs amended microcosms. In microcosms, Ag-NPs were not detected in the crystalline form but were available in the ionic form that inhibited most bacterial populations and resulted in a limited degradation profile of oil, specifically the low molecular weight fractions. Ag-NPs amended microcosms showed a significant reduction (80%) in C23DO gene expression and a detrimental effect on bacterial populations including key players like Mycobacterium sp., Microbacterium sp., and Thauera sp. involved in the biodegradation of petroleum hydrocarbons., (© 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Different weathering factors act to change petroleum composition once it is spilled into the environment. n-Alkanes, biomarkers, low-molecular weight polyaromatic hydrocarbons and sulfur heterocycles compositional changing in the environment have been extensively studied by different researchers and many parameters have been used for oil source identification and monitoring of weathering and biological degradation processes. In this work, we studied the fate of medium-molecular weight polycyclic aromatic disulfur heterocycles (PAS2Hs), up to ca. 900Da, of artificially weathered Flotta North Sea crude oil by ultra high-resolution Fourier transform ion cyclotron resonance mass spectrometry. It was found that PAS2Hs in studied crude oil having double bond equivalents (DBE) from 5 to 8 with a mass range from ca 316 to 582Da were less influenced even after six months artificial weathering experiment. However, compounds having DBEs 12, 11 and 10 were depleted after two, four and six months weathering, respectively. In addition, DBE 9 series was more susceptible to weathering than those of DBE 7 and 8., (Copyright © 2014 Elsevier Ltd. All rights reserved.)

Biomarkers and low-molecular weight polyaromatic compounds have been extensively studied for their fate in the environment. They are used for oil spill source identification and monitoring of weathering and degradation processes. However, in some cases, the absence or presence of very low concentration of such components restricts the access of information to spill source. Here we followed the resistance of high-molecular weight sulfur-containing aromatics to the simulated weathering condition of North Sea crude oil by ultra high-resolution Fourier transform ion cyclotron resonance mass spectrometry. The sulfur aromatics in North Sea crude having double bond equivalents (DBE) from 6 to 14 with a mass range 188-674Da were less influenced even after 6 months artificial weathering. Moreover, the ratio of dibenzothiophenes (DBE 9)/naphthenodibenzothiophenes (DBE 10) was 1.30 and 1.36 in crude oil and 6 months weathered sample, respectively reflecting its weathering stability. It also showed some differences within other oils. Hence, this ratio can be used as a marker of the studied crude and accordingly may be applied for spilled oil source identification in such instances where the light components have already been lost due to environmental influences., (Copyright © 2012 Elsevier Ltd. All rights reserved.)

Polycyclic aromatic hydrocarbons (PAHs) play a huge role in environmental analytical chemistry, both as pollutants and as markers for many processes. On the other hand, polycyclic aromatic sulfur heterocycles (PASHs; heterocyclic compounds related to PAHs) have been studied far less intensely, but such studies may lead to a great deal of information not available through the study of PAHs. Here we discuss analytical aspects of PASHs in environmental matrices and their use as information carriers. Since PASHs accompany PAHs in sampling and work-up, it is not necessary to expend much extra analytical effort in order to analyze them. This work reviews how they can provide information on diverse processes such as petroleum, industrial and vehicular pollution, and sources of air and marine pollution.

5-Benzylidene-2-thiobarbituric acid (BzTBA), a pyrimidine derivative, was used to modify the surface of silica gel-chloropropyltrimethoxysilane (Si-Cl) via chemical immobilization to produce a new pyrimidine silica phase (Si-BzTBA). Identification of the surface modification was characterized and performed on the basis of infrared as well as elemental analysis. Thermal desorption method was found to give 0.129-0.143 mmol g(-1) as surface coverage values. Metal sorption properties of Si-BzTBA were also studied and the evaluated results refer to the high metal sorption of Si-BzTBA for copper(II), mercury(II), cadmium(II), and lead(II) with the same order. These four Si-BzTBA-metal complexes were also synthesized and the stoichiometric ratios were identified as 1:1 except lead complex was found to give a 1:2 ratio. Electron impact-mass spectrometric analysis (EI-MS) with 70 eV ionization energy was used as a potential thermal method for the confirmation of surface modification of Si-BzTBA and its metal complexes based on fragmentation elucidation of thermally desorbed ion peaks. The EI-MS of Si-BzTBA was found to show several characteristic fragment ion peaks that are directly related to the chemical binding of BzTBA to SiCl phase. Differential scanning calorimetry study (DSC) was also performed to evaluate the various kinetic and thermodynamic parameters of thermal degradation processes and have been enumerated. The results of EI-MS and DSC are very similar in many respects.

This study represents a forensic chemical analysis to define the liability for the coastal bitumens polluting the beaches of the Mediterranean city of Alexandria. Six tar balls collected from several locations along the coast of the city were analyzed for their acyclic and polycyclic hydrocarbons as well as sulfur heterocycles using GC/FID, GC/AED and gas chromatography/mass spectrometry techniques. The analysis of one Egyptian crude oil is also included as a possible source oil. The tar ball samples were at early stages of weathering. Based on the GC traces and biomarker signatures, the tar balls could be genetically different. One sample collected from the Eastern Harbor region appears to be a Bunker C type fuel produced from Egyptian crudes. The refining process has removed the low molecular weight components. On the other hand, the wide n-alkane distribution together with the absence of an unresolved complex mixture suggests that crude oils probably from tank washings, ballast discharges or accident spills from tankers could have contributed significantly to the other tar ball samples. The distribution of source specific hopane and sterane markers revealed that the tar samples probably originate from different oil fields.