Presence Of Acetic Acid Research Articles

Glycosaminoglycan Metabolism by Commensal and Pathogenic Bacteria of the Urinary Tract

Urinary tract infections (UTIs) are among the most common adult bacterial infections. When a patient suffers ≥3 UTIs per year, it is defined as recurrent UTI (rUTI). Current rUTI therapies rely on antimicrobials to achieve sterility in the urinary tract (UT). However, research has shown that urine is not sterile in healthy individuals and that the urinary microbiota has not been fully characterized. A constant flux of urine containing electrolytes, osmolytes, amino acids, and carbohydrates supply nutrients to support urinary microbiota. An overlooked carbon source in the UT is the glycosaminoglycan (GAG) layer lining the urothelium. GAGs are linear heteropolysaccharides containing repeating disaccharide units composed of uronic acid (or galactose) and amino sugars. Previous studies have determined that species belonging to the genera Lactobacillus, Bifidobacterium, and Bacteroides derived from the human gut express enzymes that degrade GAGs into metabolizable disaccharides. However, the ability of the urinary microbiota and invading uropathogens to metabolize GAGs has not been assessed. To fill this knowledge gap, we screened a library of urinary bacteria clinically isolated from women with and without rUTI for the ability to degrade and utilize GAGs such as chondroitin sulfate (CS), heparan sulfate (HS), and hyaluronic acid (HA). To test this, we developed a plate-based, semi-quantitative GAG degradation and growth assay. Briefly, isolates were inoculated in modified MRS lacking carbohydrates and supplemented with CS, HS, HA, glycogen, glucose, or maltose. The resuspension was added to a microtiter plate and incubated at 35°C for 72 hours in microaerophilic conditions. Optical density at 600nm (OD600) was measured to record growth. Plates were centrifuged and the cell-free supernatant was added to 1% bovine serum albumin (BSA), which complexes with GAGs to form a white precipitate in the presence of acetic acid. To calculate percent GAG degradation, OD600 was recorded after addition of acetic acid and compared to bacteria-free controls. Using this method, we screened 16 representative isolates of four Lactobacillus species (L. crispatus, L. gasseri, L. delbrueckii, L. vaginalis), Streptococcus agalactiae, and Escherichia coli. Preliminary results show that all urinary Lactobacilli and E. coli exhibited no GAG degradation. However, all 4 Lactobacillus species were able to utilize maltose as a sole carbon source. Two S. agalactiae strains were able to degrade HA, but no other GAGs. Although urinary Lactobacilli were unable to degrade GAGs in vitro, these findings suggest that urinary Lactobacilli may rely on a bacterial consortia or host enzymes to degrade and utilize GAGs. Future work will focus on screening more common urinary microbiota species and analyzing the ability of urinary Lactobacilli to utilize GAGs in the presence of host GAG degradative enzymes and in co-culture with S. agalactiae. Upon completion, this work will define the metabolic requirements of key urinary microbiota and elucidate metabolic interactions between the urinary microbiota, host environment, and invading uropathogens.

How Small Molecules Affect the Thermo-Oxidative Aging Mechanism of Polypropylene: A Reactive Molecular Dynamics Study.

Understanding the aging mechanism of polypropylene (PP) is fundamental for the fabrication and application of PP-based materials. In this paper, we present our study in which we first used reactive molecular dynamics (RMD) simulations to explore the thermo-oxidative aging of PP in the presence of acetic acid or acetone. We studied the effects of temperature and oxygen on the aging process and discussed the formation pathways of typical small molecule products (H2, CO, CO2, CH4, C2H4, and C2H6). The effect of two infection agents, acetic acid and acetone, on the aging reaction was analyzed emphatically. The simulation results showed that acetone has a weak impact on accelerating the aging process, while acetic acid has a significant effect, consistent with previous experimental studies. By tracking the simulation trajectories, both acetic acid and acetone produced small active free radicals to further react with other fragment products, thus accelerating the aging process. The first reaction step of acetic acid is often the shedding of the H atom on the hydroxyl group, while the reaction of acetone is often the shedding of the H atom or the methyl. The latter requires higher energy at lower temperatures. This is why the acceleration effect of acetone for the thermo-oxidative aging of PP was not so significant compared to acetic acid in the experimental temperature (383.15 K).

Synthesis of Phosphonomethylated Bromoacetylfurans and Their\t\t\tReactions with 1,3-Dicarbonyl Compounds

Bromination of (diethoxyphosphorylmethyl)acetylfurans with dioxane dibromide\t\t\t\t\tin the mixture of chloroform and acetic acid in presence of traces of hydrogen\t\t\t\t\tbromide at room temperature proceeds selectively at the methyl group of ketone\t\t\t\t\tdoes not involving phosphonate group. Obtained bromoacetyl derivatives were used\t\t\t\t\tfor alkylation of acetoacetic ester and cyclohexan-1,3-dione. Reaction of\t\t\t\t\t1,4-diketone prepared from acetoacetic ester with hydrazine hydrate in ethanol\t\t\t\t\tat room temperature leads to formation of furylpyrazines due to aromatization of\t\t\t\t\tintermediate azines by means of air oxygen.

Understanding Acid-Promoted Polymerization of the N-Substituted Glycine N-Thiocarboxyanhydride in Polar Solvents.

Polymerization of N-substituted glycine N-thiocarboxyanhydrides (NNTAs) is a promising pathway to prepare functional polypeptoids benefiting from their tolerance to nucleophilic impurities. However, controlled NNTA polymerization is hard to achieve in amide polar solvents, including N,N-dimethylacetamide (DMAc), N,N-dimethylformamide (DMF), and N-methyl pyrrolidone (NMP), the only aprotic solvents for many biomacromolecules and polypeptoids. In the present work, we successfully achieve controlled NNTA polymerization in amide polar solvents by adding acetic acid as a promoter. The promotion is applied to the polymerization of sarcosine NTA, N-ethyl glycine NTA, and N-butyl glycine NTA. DMAc, DMF, and NMP are suitable solvents to prepare polypeptoids with designable molecular weights and low dispersities (1.06-1.21). The polysarcosines with high molecular weights are prepared up to 35.2 kg/mol. A kinetic investigation quantitatively reveals that the presence of acetic acid not only accelerates the polymerization, but also suppresses H2S-catalyzed decomposition of NNTAs by decreasing the concentration of H2S dissolved in polar solvents. Benzoic acid is also able to promote the polymerization, while trifluoroacetic acid, phosphoric acid, and phenol are not appropriate promoters. The moderate acidity of acids is essential. l-Methionine, l-tryptophan, and l-phenylalanine, which are dissolved in DMF, initiate the controlled polymerization of sarcosine-NTA in the presence of acetic acid and introduce functional end groups to polysarcosines quantitatively. In DMAc, hydrophilic vancomycin is grafted by poly(N-butyl glycine). The amphiphilic product dissolves in dichloromethane and stabilizes water-in-oil emulsion.

Synthesis and Electrochemical Investigations of the [FeFe]‐Hydrogenase H‐Cluster Mimics Mediated by Bicyclic Dithiols Derivative

AbstractBiomimic of the active site of [FeFe]‐hydrogenase containing bicyclic dithiols as bridging linker has been synthesized and characterized using different spectroscopic methods. The influence of this linker on the redox properties and the catalytic behavior of the resulted binuclear complex was investigated using cyclic voltammetry, showing that it can catalyze the reduction of protons to H2 in the presence of acetic acid (AcOH). Moreover, the results revealed that the bicyclic dithiolene linker has improved the chemical stability of the reduced species and caused a shift to less negative potential in comparison to the synthetic models that mimic the active site of [FeFe]‐hydrogenase reported in the literature. In addition, the structure of the resulted binuclear complex mediated by bicyclic dithiols as bridging linker was confirmed by X‐ray diffraction analysis.

Development of an Ion-Pair Dispersive Liquid-Liquid Microextraction Method Based on a Ternary Deep Eutectic Solvent for Determination of Some Herbicide Residues in Edible Oil Samples.

An ion-pair deep eutectic solvent (DES)-based dispersive liquid-liquid microextraction method was introduced and applied for the extraction of some acidic herbicides from edible oil samples prior to their determination by high performance liquid chromatography. First, a ternary DES composed of decanoic acid, dichloroacetic acid, and phosphocholine chloride is prepared under mild conditions. Then, the analytes are extracted into an alkaline solution from the oil samples by deprotonation of the herbicides. Afterward, the deprotonated analytes are extracted into the prepared DES with the aid of tri-butyl amine (as an ion-pair agent) in the presence of acetic acid (as a pH adjustment agent and dispersive solvent). The validation parameters indicated that the method has low limits of detection (0.09-0.72ngmL-1) and quantification (0.30-2.3ngmL-1), an acceptable percision (relative standard deviation≤ 9.0%) and high extraction recoveries (85-94%), and enrichment factors (566-626). The method was used in the analysis of 35 edible oil samples to assessment the studied analytes and the presence of haloxyfop was confirmed in three corn oils.

SYNTHESIS OF ORGANIC–INORGANIC HYBRID COATINGS FOR THE PROTECTION OF ALUMINUM SUBSTRATES

A silica-based organic–inorganic hybrid coating has been developed for corrosion protection of aluminum substrates by dip-coating technique. The hybrid sols were prepared by hydrolysis and condensation of trimethoxy(7-octen-1-yl)silane (TMOS) and tetraethyl orthosilicate (TEOS) in the presence of acetic acid. Structural characterization of the hybrid coatings was performed using powder X-ray diffraction analysis (PXRD). The morphology of the coating has been studied by scanning electron microscope (SEM). Electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization (PDP) tests have been performed, and the results showed that the silane coatings had high corrosion resistance. The heat treatment of the coatings at various temperatures have been investigated, and the results show that 130∘C is an optimized temperature. The results expose that the hybrid coating enhanced the corrosion protection of aluminum in aqueous 3.5% NaCl solution.

Dihydroquinazolin-4(1H)-one derivatives as novel and potential leads for diabetic management.

A variety of dihydroquinazolin-4(1H)-one derivatives (1-37) were synthesized via "one-pot" three-component reaction scheme by treating aniline and different aromatic aldehydes with isatoic anhydride in the presence of acetic acid. Chemical structures of compounds were deduced by different spectroscopic techniques including EI-MS, HREI-MS, 1H-, and 13C-NMR. Compounds were subjected to α-amylase and α-glucosidase inhibitory activities. A number of derivatives exhibited significant to moderate inhibition potential against α-amylase (IC50 = 23.33 ± 0.02-88.65 ± 0.23μM) and α-glucosidase (IC50 = 25.01 ± 0.12-89.99 ± 0.09μM) enzymes, respectively. Results were compared with the standard acarbose (IC50 = 17.08 ± 0.07μM for α-amylase and IC50 = 17.67 ± 0.09μM for α-glucosidase). Structure-activity relationship (SAR) was rationalized by analyzing the substituents effects on inhibitory potential. Kinetic studies were implemented to find the mode of inhibition by compounds which revealed competitive inhibition for α-amylase and non-competitive inhibition for α-glucosidase. However, in silico study identified several important binding interactions of ligands (synthetic analogues) with the active site of both enzymes.

One-pot approach: Tandem consecutive Ugi-4CR/ACM-type reaction towards the synthesis of functionalised quinoline-2(1H)-one scaffolds

We report the synthesis of functionalised quinolin-2-(1H)-one analogues by a one-pot approach through a tandem consecutive Ugi-4CR/intramolecular alkyne-carbonyl metathesis (ACM) type reaction, in which Pd(OAc)2 is used as a catalyst in the presence of acetic acid. The first step is the preparation of an Ugi-4CR intermediate using simple precursors 2′-aminoacetophenone and cyclohexyl isocyanide with various propiolic acids and aldehydes.

Mitigation of top‐ and bottom‐of‐the‐line CO2 corrosion in the presence of acetic acid (I): pH control using methyl diethanolamine

AbstractTemperature differences between the top and the base of pipelines can, in specific circumstances, drive severe corrosion due to condensed fluids at the top‐of‐the‐line. Here, we measure corrosion at the top‐of‐the‐line in the condensate phase and, simultaneously, in the immersed phase at the bottom‐of‐the‐line using an electrochemical approach. With CO2‐saturated chloride brine, corrosion at the top‐of‐the‐line increased with fluid temperature (due to increased condensation rates), whereas at the bottom‐of‐the‐line, the corrosion rate decreased (due to ferrous carbonate precipitation). The addition of acetic acid increased the corrosion rate at both top and bottom of the line, with any ferrous carbonate films being removed by dissolution. The addition of methyl diethanolamine (MDEA) reduced corrosion rates significantly because of the increased pH in both the condensate at the top‐of‐the‐line and under immersion at the bottom‐of‐the‐line, reducing the solubility of FeCO3. Overall, the addition of acetic acid was confirmed to damage and remove protective FeCO3 films. However, continuous films were not re‐established after MDEA additions, rather porous and generally unprotective films were formed.

Eradication of Acinetobacter baumannii Planktonic and Biofilm Cells Through Erythrosine-Mediated Photodynamic Inactivation Augmented by Acetic Acid and Chitosan.

Photodynamic inactivation (PDI) is an attractive treatment modality for multidrug-resistant bacterial infections. The effectiveness of photosensitization by anionic photosensitizers such as erythrosine B can be further enhanced by the addition of biological or chemical molecules. This study aimed to investigate of the enhancement effect of acetic acid and chitosan on erythrosine-mediated PDI of Acinetobacter baumannii in planktonic and biofilm forms. The planktonic cell growth of three A. baumannii strains was subjected to PDI by using erythrosine B (50 µM) in 0.01% acetic acid and green laser light (530 nm) at fluence of 40 J/cm2. The phototoxic effect of erythrosine B (100 µM) in combination with chitosan (12.5 mg/ml) (in a solution of acetic acid) at fluence of 80 J/cm2 on biofilms was also evaluated. Finally, the cytotoxicity and phototoxicity of the mentioned mixture were assessed on human fibroblasts. Planktonic cells of all three studied A. baumannii strains were almost eradicated by erythrosine B-mediated PDI in the presence of acetic acid. Also, PDI combined with chitosan resulted in a marked decrease in the number of viable biofilm cells (> 3 log10 CFU). At the same experimental conditions, only 15% of the fibroblasts were photoinactivated. The results showed that PDI by using erythrosine B in acetic acid is very effective against A. baumannii planktonic cells and could eliminate them significantly. Also, chitosan enhanced the anti-biofilm efficacy of erythrosine B-mediated PDI against A. baumannii, suggesting that combination therapy may be useful in targeting biofilms.

Top-of-line corrosion in the presence of carbon dioxide for gas production facilities

Aspects of the development of corrosion processes under conditions of moisture condensation in the gas phase (top-of-line corrosion) in the presence of carbon dioxide, which lead to the formation of local damages, have been investigated. The influence of various factors on corrosion processes under conditions of moisture condensation (top-of-line corrosion) was studied: the acidity of the media (presence of acetic acid), the presence of alcohol (methanol is used in gas production as an inhibitor of hydrate formation), temperature, type of steel and the presence of a weld. In addition to the listed factors, the moisture content in the gas is the determining factor for the development of this type of corrosion under CO2 conditions. The rate of development of corrosion processes depends on the amount and composition of the liquid condensing on the metal surface. The rate of local carbon dioxide corrosion at top-of-line corrosion can reach several mm / year.

Influence of the Ni-Co/Al-Mg Catalyst Loading in the Continuous Aqueous Phase Reforming of the Bio-Oil Aqueous Fraction

The effect of catalyst loading in the Aqueous Phase Reforming (APR) of bio-oil aqueous fraction has been studied with a Ni-Co/Al-Mg coprecipitated catalyst. Because of the high content of water in the bio-oil aqueous fraction, APR could be a useful process to convert this fraction into valuable products. Experiments of APR with continuous feeding of aqueous solution of acetol, butanol and acetic acid as the only compound, together with a simulated and a real aqueous fraction of bio-oil, were carried out. Liquid products in the liquid effluent of the APR model compounds were quantified and the reaction pathways were revised. The increase of catalyst loading produced an increase of gas production and a gas with higher alkanes content. Acetol was the compound with the highest reactivity while the conversion of acetic acid was very low. The presence of acetic acid in the feed caused catalyst deactivation.

Vinyl sulfone synthesis via copper-catalyzed three-component decarboxylative addition.

The synthesis of vinyl sulfone derivatives via the reaction of arylpropiolic acids, K2S2O5, and aryl boronic acids is reported. The CuBr2/1,10-phenanthroline catalytic system in the presence of acetic acid provides the desired vinyl sulfones in moderate to good yield. Furthermore, the methodology features excellent functional group tolerance.

A facile and efficient route to one-pot synthesis of new cyclophanes using vinamidinium salts.

In this study, an efficient method for the synthesis of new cyclophanes (5a–f, 6a–g) through the condensation of 1,4-phenylenedimethanamine (3) or 2,3,5,6-tetramethylbenzene-1,4-diamine (4) with 2-substituted vinamidiniums (2a–g) is described. The cyclophane derivatives are obtained in good to excellent yields in the presence of acetic acid in refluxing acetonitrile after 15 h. The structure of new compounds was validated based on their spectral data (1H NMR, 13C NMR, IR) and elemental analysis.

Visible-light-driven reductive coupling of aromatic ketones using perylene derivatives as photoredox catalysts: Improvement of reaction efficiency by the addition of acetic acid

The photoredox-catalyzed reductive coupling of aromatic ketones using perylene as a simple organic photoredox catalyst was improved significantly by the addition of acetic acid. For example, the reductive coupling of acetophenone in the absence of acetic acid gave the corresponding 1,2-diol in only 12% yield, whereas that in the presence of acetic acid (10 eq relative to acetophenone) gave the 1,2-diol in 67% yield. The addition of acetic acid also effectively improved the reductive coupling of other aromatic ketones. The effect of acetic-acid addition was also remarkable in catalytic processes using P-perylene, a perylene derivative bearing a polymethacrylate moiety, as a polymer-type photoredox catalyst in place of perylene.

Theoretical Molecular Properties Prediction, Docking and Antimicrobial Studies on Anisidine-Isatin Schiff Bases

The continuous intake of a specific antibiotic for diseases is continuously reducing the immunity of the human in course of time, which includes Covid-19 treatment. Recent research on Schiff bases shows the promising biological activities and good antibacterial results. In this study, three Schiff bases with lactam ring using isatin and three different anisidines in presence of acetic acid were synthesized and characterized. Drug likeness was examined using Molsoft and docking against the target proteins such as 5J6R, 3L9L, 5HVY, covid main protease and 3ZBO proteins for drug suitability. The experimental antibacterial activity against Gram-positive strains like Staphylococcus aureus, Bacillus subtilis and Staphylococcus epidermidis. Among the synthesized compounds, three Schiff bases ortho and meta substituted compounds exhibited good results when compared to para compound, where the methoxyl group position effect was observed.

Encapsulating Keggin‐H 3 PW 12 O 40 into UIO‐66(Zr) for manufacturing the biodiesel

In the presence of acetic acid as modulated agent, Keggin-H3PW12O40 (K-PW12) has been encapsulated into UIO-66(Zr) by the solvothermal method. The as-synthesized K-PW12@UIO-66(Zr) composite has further been characterized by PXRD, TG, FTIR, ICP-AES, N2 isothermal adsorption, SEM and TEM. The results exhibit that Keggin-H3PW12O40 is entrapped into the interior cage of UIO-66(Zr) framework which is enlarged by losing terephthalic acid linker in the presence of acetic acid. K-PW12@UIO-66(Zr) composite can efficiently catalyse the esterification of methanol and oleic acid into biodiesel.

Synthesis, in vivo biological assessment and molecular docking study of some newer indole derivatives as COX 1/2 inhibitors

BackgroundDue to the presence of several serious side effects such as erosion and bleeding in the gastric mucosal layer which are linked with Non-steroidal anti-inflammatory agents and a lot of these adverse effects may be dangerous for life and may cause numerous mortalities, demand for new antiinflammatory and analgesic agents has become an important task in medicinal chemistry to improve therapeutic efficacy as well as safety. MethodIn the search for new anti-inflammatory and analgesic molecules with greater potency, some novel indole derivatives (SK-1 to SK-9) were attained by chloroacetylation process of indole after that reaction through some aromatic aldehydes with the presence of acetic acid in absolute ethyl alcohol. IR, 1H NMR, and 13C NMR spectra were used for the structure elucidation of obtained chemical compounds. In this context, the analgesic and anti-inflammatory activity were evaluated for synthetically obtained new chemical compounds. Furthermore, the molecular docking studies were performed to elucidate the binding modes of synthesized ligands in the active pockets of Cox-1 / 2 enzymes. ResultAmong the compounds assessed, SK-2 and SK-8 demonstrated potent analgesic & anti-inflammatory activities when compared to ibuprofen and diclofenac sodium as reference drugs. Compound SK-4 has exhibited significant anti-inflammatory activity while compounds SK-1 and SK-5 have shown significant analgesic action when compared to the control. Molecular docking studies indicated that SK2 compound exhibited appreciable binding affinity (-9.16 kcal/mol) towards the COX-2 enzyme and mandatory interactions for COX-2 enzyme inhibition. ConclusionIt might be established from the present study that prepared compounds are unique in terms of their structure and noticeable biological action. In search of and initiation of a novel group of antiinflammatory and analgesic molecules, these compounds might be helpful.

Catalytic Four-Electron Reduction of Dioxygen by Ferrocene Derivatives with a Nonheme Iron(III) TAML Complex.

A mononuclear nonheme iron(III) complex with a tetraamido macrocyclic ligand (TAML), [(TAML)FeIII]- (1), is a selective precatalyst for four-electron reduction of dioxygen by ferrocene derivatives in the presence of acetic acid (CH3COOH) in acetone. This is the first work to show that a nonheme iron(III) complex catalyzes the four-electron reduction of O2 by one-electron reductants. An iron(V)-oxo complex, [(TAML)FeV(O)]- (2), was produced by oxygenation of 1 with O2 via the formation of triacetone triperoxide (TATP), acting as an autocatalyst that shortened the induction time for the generation of 2. Decamethylferrocene (Me10Fc) and octamethylferrocene (Me8Fc) reduced 2 to 1 by two electrons in the presence of CH3COOH to produce decamethylferrocenium cation (Me10Fc+) and octamethylferrocenium cation (Me8Fc+), respectively. Then, 1 was oxygenated by O2 to regenerate 2 via the formation of TATP. In the cases of ferrocene (Fc), bromoferrocene (BrFc) and 1,1'-dibromoferrocene (Br2Fc), initial electron transfer from ferrocene derivatives to 2 occurred; however, neither a second proton-coupled electron transfer from ferrocene derivatives to 2 nor a catalytic four-electron reduction of O2 occurred.