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In this section of Resonance, we invite readers to pose questions likely to be raised in a classroom situation. We may suggest strategies for dealing with them, or invite responses, or both. "Classroom" is equally a forum for raising broader issues and sharing personal experiences and viewpoints on matters related to teaching and learning science. The tartaric acid—glacial acetic acid system is found to be a simple, inexpensive and environmentally benign catalyst for the N-acetylation of primary aromatic amines. [ABSTRACT FROM AUTHOR]

Objective: To update the analysis of mortality of a cohort of dyestuff workers, in northern Italy, heavily exposed to carcinogenic aromatic amines. Methods: We updated to 2018 overall and cause-specific mortality in a cohort of 590 male workers heavily exposed to carcinogenic aromatic amines in a dyestuff factory from 1922 to 1972. Workers were censored at age 85. Expected cases for the period 1946-2018 were computed using Piedmont mortality rates and standardized mortality ratios (SMR) were computed. Results: Between 1946 and 2018, 470 deaths were reported. The overall SMR from all causes was 1.59 (95% confidence interval [CI] 1.45-1.74) and the SMR from all cancers was 2.05 (95% CI = 1.77-2.37); compared to a previous report, there were 4 additional deaths from bladder cancer, for a total of 60 deaths compared with 4.0 expected (SMR 14.86, 95% CI 11.34-19.12). The SMR for bladder cancer increased with younger age at first exposure and longer duration of exposure, while it decreased with time since last exposure, albeit it was still 3.5, 30, or more years since last exposure. An increased risk was observed among workers exposed to fuchsine or ortho-toluidine (SMR=16.3; 95% CI = 6.0-35.5). Conclusions: This 73-year follow-up confirms the results from previous analyses, with increased overall mortality, and increased mortality from all cancers and especially for bladder cancer. The excess risk of bladder cancer persisted several decades after stopping exposure. [ABSTRACT FROM AUTHOR]

Copyright of Polimery is the property of Industrial Chemistry Research Institute and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Revista de la Sociedad Química del Perú is the property of Sociedad Quimica del Peru and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Environmental aspects and ecological production has become a great challenge for leather industry. In this study, the possibility to regain of leathers consisting highly rate of harmful azo colorants were investigated. Sodium perborate, sodium percarbonate and hydrogen peroxide as oxidative bleaches were used for the removal of azo dyes in leather. Leathers were firstly bleached at the pilot scale. Color measurements of the leathers were carried out with spectrophotometric method following the bleaching processes. As a result of the calculation of color differences (ΔE), 7% sodium perborate were elicited as optimum parameter on the bleaching effect. After determining the optimal bleach at the pilot scale, bleaching and re-dyeing processes were performed on the batch production. With the bleaching process, 35 ppm of azo dye content in leather according to ISO 17234-1 standard method was reduced under 5 ppm. Chromium( VI) formation on bleached leather samples have been examined with UV-Visible spectrophotometer at 540 nm according to EN ISO 17075 standard. Textural changes on the leathers after bleaching process were also observed by strength tests and scanning electron microscope (SEM) analysis. According to the findings of the research, Cr(VI) contents were detected under 3 ppm and strength properties of leathers showed slightly decreases not in the statistically remarkable levels. By this practically applicable way in the industrial scale, resellability of the leathers was ensured and thus, the potential danger of banned arylamine compounds which are an important problem in ecological production and eco-labeling of leather has been eliminated. [ABSTRACT FROM AUTHOR]

As a chiral precursor for the important anticoagulant Edoxaban, enantioselective synthesis of (S)-3-cyclohexene-1-carboxylic acid is of great significance. The complicated procedures and generation of massive solid waste discourage its chemical synthesis, and the alternative biocatalysis route calls for an enzyme capable of asymmetric hydrolysis of racemic methyl-3-cyclohexene-1-carboxylate. To this end, we engineered the E. coli esterase BioH for improved S-enantioselectivity via rational design. By combinatorial modulation of steric and aromatic interactions, a positive mutant Mu3 (L24A/W81A/L209A) with relatively high S-selectivity in hydrolyzing racemic methyl-3-cyclohexene-1-carboxylate was obtained, improving the enantiomeric excess from 32.3% (the wild type) to 70.9%. Molecular dynamics simulation was conducted for both (R)- or (S)- complexes of the wild type and Mu3 to provide hints for the mechanism behind the increased S-selectivity. Moreover, the reaction conditions of Mu3 in methyl-3-cyclohexene-1-carboxylate hydrolysis was optimized to improve the conversion rate to 2 folds. Rational design of BioH with enhanced enantioselectivity towards methyl (S)-3-cyclohexene-1-carboxylate. [ABSTRACT FROM AUTHOR]

In this study, we examined the polymerization performance of methyl methacrylate (MMA) initiated with partially oxidized tri-nbutylborane (TBBO) compared to that initiated with benzoyl peroxide and aromatic tertiary amine (BPO/amine) system. In the bulk polymerization of MMA at 37°C, conversion initiated with TBBO after 3 h was nearly quantitative, whereas the conversion with the BPO/amine system was low (~20%). The number-averaged and weight-averaged molecular weight of the TBBO-initiated polymer was more than twice as high as that of the BPO/amine-initiated polymer. Electron spin resonance (ESR) analysis of MMA polymerization indicated that the TBBO-initiated system maintained its radical intensities for a longer period than the BPO/amine-initiated system. Furthermore, the radical fragments in the TBBO-initiated PMMA after 72 h were still active as a polymerization initiator for MMA. These findings suggest that the polymerization mechanism of MMA initiated by TBBO functions as a living-like polymerization initiator. [ABSTRACT FROM AUTHOR]

Highlights • Overview of why amines containing aromatic functionality should be considered as CO 2 absorbents. • A combination of calculation and pilot plant results highlight the performance of aromatic amines. • Overall, aromatic amines (as defined here) combine capture performance and stability along with low toxicity and biodegradability. Abstract Aqueous amines are the most common and technically mature class of chemical absorbents used for CO 2 separation applications. They have been developed over decades and have the capability to be tuned to operate under a range of gas compositions and achieve very high levels of CO 2 removal. Previously non-cyclic and some cyclic aliphatic amine molecules have been used. Aromatic amines have not received significant consideration. In this work it is argued that the structural rigidity and stability that aromaticity affords gives these amines a unique set of properties in terms of absorption performance, stability and biodegradability that means they should be considered as a promising class of amine for CO 2 absorption applications. [ABSTRACT FROM AUTHOR]

Copyright of Polimery is the property of Industrial Chemistry Research Institute and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Kobunshi Ronbunshu is the property of Society of Polymer Science and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Aromatic amines (AAs) are polar organic chemicals with a wide environmental distribution originating from various sources, such as tobacco smoke, diesel exhaust, and dermal absorption from textile products with azo dyes. The toxicity profile of AAs is directly related to the amino group's metabolic activation and the generation of the reactive intermediate, forming DNA adducts and potential carcinogenicity. Urinary levels of 8-hydroxy-2′-deoxyguanosine (8OHdG) are an important biomarker of DNA damage. Since AAs have been shown to cross the placental barrier, being a risk factor for adverse birth outcomes, prenatal exposure is a great public health concern. The present study aimed to measure the urinary levels of 58 AAs in Brazilian pregnant women (n = 300) and investigated the impact of this exposure on DNA damage by quantifying 8OHdG levels. The influence of tobacco smoke exposure and dermal absorption of AAs by clothes on urinary levels was also assessed. The results showed a 100% detection rate for eight AAs, two of them regulated by the European Union (2,6-dimethylaniline and 2,4-diaminotolune). Hundreds of AAs may be derived from aniline, which here showed a median of 1.38 ng/mL. Aniline also correlated positively with 2,6-dimethylaniline, p -aminophenol, and other AAs, suggesting exposure to multiple sources. The present findings suggest that both tobacco smoke and dermal contact with clothes containing azo dyes are potential sources that might strongly influence urinary levels of AAs in Brazilian pregnant women. A multiple regression linear model (R2 = 0.772) suggested that some regulated AAs (i.e., 2-naphthylamine and 4-aminobiphenyl), nicotine, smoke habit, age, and Brazilian region could induce DNA damage occurrence, increasing the levels of 8OHdG. Given the limited available data on human exposure to carcinogenic AAs, as well as the lack of toxicological information on those non-regulated, further studies focused on measuring their levels in human fluids and the potential exposure sources are clearly essential. [Display omitted] • Results showed a detection rate of 100% for eight aromatic amines (two regulated). • Aniline correlates with other aromatic amines, suggesting exposure to multiple sources. • Tobacco smoke and dermal contact with clothes are potential sources of aromatic amines. • Regulated aromatic amines and nicotine can induce DNA damage occurrence. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • CMOEDA can describe the basicities of amines and related compounds. • Polarization, not induction, determines the alkyl effect on amines basicities. • Electrostatics interactions determines substituent effects in aromatic amines. • Hydridization/geometry does not influences basicities of endocyclic and heterocyclics. Abstract Acidities and basicities are normally rationalized with the help of concepts like inductive and delocalization effects. There are, however, difficulties in estimating these quantities for most of systems. In this work, energy decomposition analysis has been used to interpret the basicity of a series of nitrogen compounds. With the help of CMOEDA (LMOEDA) partitioning scheme, the increase of basicities with the increasing alkyl chain length of amines was attributed mainly to polarization (orbital rearrangement) interactions. The variation in basicites among cyclic amines, which has been interpreted as a consequence of geometry/hybridization, was also attributed mainly to polarization, with electrostatic interactions also playing an important role in some cases. The effect of the substituent (electron attractor or electron donor) on the basicity of aniline was studied as a model to aromatic compounds. In this case, electrostatic is the most important factor. Finally, some simple conjugated nitrogen compounds were investigates, namely, formamide, thioformamide and enamine. The smaller basicity of formamide compared to methylamine is attributed mainly to electrostatic interactions, as is explained in detail. Geometrical changes (from a planar to a pyramidal structure) plays a secondary role. Combination of EDA results with a solvent model allows the interpretation of p K a values. [ABSTRACT FROM AUTHOR]

Microbes have potential to convert non-toxic azo dyes into hazardous products in the environment. However, the role of microbes in biotransforming such presumably non-toxic dyes has not been given proper attention, thereby, questions the environmental safety of such compounds. The present study assessed salinity driven microbial degradation of an unregulated azo dye, Acid orange 7 (AO7), under moderately halophilic conditions of textile effluent. The halophilic microbial consortium from effluent decolorized ~97% AO7 (50–500 mg L −1 ). The consortium efficiently decolorized the dye at different pH (5–8) and salinity (5–18% NaCl). The 16S rRNA sequence analyses confirmed the presence of Halomonas and Escherichia in the consortium. The FTIR and GC-MS analyses suggested microbial consortium degrade AO7 following symmetric and asymmetric cleavage and yield carcinogenic/mutagenic aromatic byproducts viz. aniline, 1-amino-2-naphthol, naphthalene, and phenyldiazene. In contrast to AO7, the biodegraded products caused molecular, cellular and organism level toxicity. The degraded products significantly reduced: radicle length in root elongation assay; shoot length/biomass in plant growth assays; and caused chromosomal abnormalities and reduced mitotic index in Allium cepa bioassay. We demonstrated that under saline conditions of textile effluent, halophilic microbes convert a presumably non-toxic azo dye into hazardous products. The study calls to review the current toxicity classification of azo dyes and develop environmentally sound regulatory policies by incorporating the role of environmental factors in governing dye toxicity, for environmental safety. [ABSTRACT FROM AUTHOR]

Aromatic amines (AA) are a group of industrial and environmental pollutants with high thermodynamic stability and carcinogenicity. Their toxicity has raised concern worldwide and calls for the development of effective elimination methods based on nanomaterials. Recently, the high adsorbing and photocatalytic efficiency of widely used metal hexacyanoferrates was observed. To confirm this, potential of potassium zinc hexacyanoferrate (ZnHCF) and potassium copper hexacyanoferrate (CuHCF) were evaluated in remediation of simulated water containing selected hazardous AAs. Highly crystralline and sharp nanocubes of ZnHCF (∼50 nm) and distorted nanocubes of CuHCF (∼100 nm) were synthesized via green route using sapindus mukorossi (raw ritha) as a biosurfactant. Under optimized conditions—concentration of amine(1.0 × 10 −4 M), catalyst (25 mg) and neutral pH, ZnHCF was found better with maximum degradation efficiency (90% of p-anisidine, 76% of p-toluidine, 71% of aniline and 70% of p-chloroaniline) followed by CuHCF (88%, 72%, 69% and 64%, respectively). This might be because of its higher zeta potential and BET surface area of ZnHCF. The highest adsorption (%) of p-anisidine on acidic surface of catalysts is probably due to its highest basicity. Statistical treatment of data fitted to various adsorption isotherms indicated the monolayer adsorption of AAs over surface of catalyst i.e., Langmuir with highest regression coefficient values (R 2 more than 0.98 for all AAs). GC–MS analysis confirmed the formation of small, non-toxic by-products such as benzoquinone, hydroquinone, but-2-enal, 4-oxobut-2-enoic acid and malealdehyde. The potential of MHCF nanoparticles can be explored more effectively in removal of organic pollutants for solving the water pollution problems. [ABSTRACT FROM AUTHOR]

Azo dyes are one of the most widely used synthetic dyes, not only for printing and dyeing textiles, but also for dyeing leather, paper, and food. The removal of azo dyes is a major challenge to the environment. Under certain conditions, azo dyes can generate aromatic amines, which can covalently bind to human DNA bases through activation, causing human lesions and inducing cancer. Among them, Congo red (CR) is the most representative azo anion dyes. In this study, a hydrothermal method assisted by ultrasound was used to create superparamagnetic Fe 3 O 4 @Al-based metal-organic framework (Fe 3 O 4 @Al-MOF) nanocomposite for the removal of CR from water. According to characterization, Fe 3 O 4 @Al-MOF was a stable nanocomposite with high specific surface area (526.73 m2·g−1) and superparamagnetic. The experimental results showed that Fe 3 O 4 @Al-MOF could remove CR efficiently within 10 min and reach equilibrium within 50 min, and the adsorption capacity was as high as 2543.6 mg·g−1 under acidic and 313 K conditions, which was higher and faster than previously reported literature. The adsorption process was consistent with the pseudo-second-order model and the adsorption data were consistent with the Langmuir monolayer adsorption isotherm. After five cycles, the removal efficiency was still up to 83.7%, indicating the commercial potential of Fe 3 O 4 @Al-MOF. The adsorption mechanism was investigated using FTIR and zeta potential, which revealed that the synergistic interplay of electrostatic interaction, π-π interaction, hydrogen bonding, and high porosity (56.7%) is the adsorption mechanism for CR removal by Fe 3 O 4 @Al-MOF. Thus, Fe 3 O 4 @Al-MOF nanocomposite is a promising material for removing CR. • Design and synthesis of a novel superparamagnetic nanocomposite Fe 3 O 4 @Al-MOF. • The nanocomposite can rapidly remove the anionic azo dye Congo Red compared with other dyes. • Maximum adsorption capacity of Congo Red was up to 2543.6 mg·g−1. • The removal rate was still higher than 83.7% after five cycles. • Fe 3 O 4 @Al-MOF can be used in green chemistry. [ABSTRACT FROM AUTHOR]

Bio-degradation is the most affordable method of azo dye decontamination, while its drawbacks such as aromatic amines accumulation and low degradation efficiency must be overcome. In this study, a novel mechanism of azo dye degradation by a fungus was discovered. At a concentration of 400 mg/L, the decolorization efficiency of Acid Red 73 (AR73) by Aspergillus tabacinus LZ-M was 90.28%. Metabolite analysis and transcriptome sequencing analysis revealed a self-redox process of AR73 degradation, where the electrons generated in carbon oxidation were transferred to the reduction of -C-N = and –N N. The metabolites, 2-hydroxynaphthalene and N-phenylnitrous amide were mineralized into CO 2 through catechol pathway and a glycolytic process. Furthermore, the mineralization ratio of dye was computed to be 31.8% by the carbon balance and electron balance. By using comparative transcriptome, a novel decoloring enzyme Ord95 was discovered in unknown genes through gene cloning. It hydrolyzed AR73 into 2-hydroxynaphthalene and N-phenylnitrous amide, containing a glutathione S-transferase domain with three arginines as key active sites. Here the new mechanism of azo dye degradation was discovered with identification of a novel enzyme in Aspergillus tabacinus LZ-M. [Display omitted] • AcId red 73 (AR73) was mineralized by A. tabacinus LZ-M under anaerobic condition. • The self-redox mechanism of AR73 degradation was revealed firstly. • New hydrolase Ord95 was found for cleaving -C-N = in AR73 at initial step. • Intermediate metabolites were degraded via catechol pathway and glycolysis process. [ABSTRACT FROM AUTHOR]

The selective catalytic reduction of nitroaromatics towards aromatic amines under mild reaction condition is an important approach to reduce the toxicity of waste effluents from industry and afterwards utilize the product as important fine organic chemical raw materials. P-nitrophenol (PNP) is chosen as the probe molecule of nitroaromatics in this study. A Fe-embedded N-doped Carbon (Fe-N-C) catalyst prepared using ZIF-8 has been identified as a highly active, selective and stable catalyst in the selective catalytic reduction of PNP. The Fe-N-C catalyst is for the first time applied in PNP reduction and found to present 100% conversion and 100% product selectivity. A mechanism investigation has been carried out to conclude that in the PNP reduction on Fe-N-C, water acts as the main hydrogen provider and sodium borohydride is the electron donator. Furthermore, the Fe-N-C catalyst works well when it is applied in PNP degradation in real water samples, which further indicates its applicability in industrial wastewater treatment. This work offers a simple and useful strategy to design robust catalysts for the selective catalytic reduction of nitroaromatics. [Display omitted] • Fe-N-C is highly active, selective, and stable in p-nitrophenol reduction. • An isotope experiment has been designed to reveal the reaction mechanism. • Fe-N-C is still robust for p-nitrophenol degradation in real water treatment. [ABSTRACT FROM AUTHOR]

The catalytic fixation of greenhouse gas CO 2 has been a hot topic of research, in which the reduction and functionalization of CO 2 is important for application. In present work, cheap and readily available alkanolamines were used as efficient catalysts with phenylsilanes as reducing agents to achieve the N-formylation reaction by constructing C-N bonds via the reaction between CO 2 and amines (aliphatic or aromatic amines) under mild conditions (40℃and 0.1 MPa). Further studies showed that present catalytic system has wide substrates application. Mono-N-formylated compounds were obtained as main products with good to high yields for all amines. It is worthy noted that for p-aminobenzylamine containing two amino groups as substrate, both amino groups are formylated and N-formylation reaction occurs mainly in aliphatic amine with high electron cloud density. Scale-up research has been performed effectively with high conversion of amine (80%) to obtain the mono-formylated product selectively. Finally, the mechanism of the reaction between amine and CO 2 is proposed via control experiments and spectra verification. Systematic mechanism studies have revealed that after polarization by polar solvent DMSO, N-methyldiethanolamine activates CO 2 by forming internal salts, which are subsequently reduced by phenylsilanes to formoxysilane intermediates and finally to form N-formylated products. [Display omitted] • Cheap alcohol amines were proved to be efficient catalysts for CO 2 reduction. • N-formylation reactions were carried out under 40 ℃ and 0.1 MPa with high selectivity. • These catalysts exhibited wide substrates application (aliphatic or aromatic amines). • Scale-up research has been performed effectively with high conversion and selectivity. • The mechanism is proposed via control experiments and spectra verification. [ABSTRACT FROM AUTHOR]

Heterocyclic aromatic amines (HAAs) were not only present in cooked foods and cigarette smoke, but also measured in airborne particles and diesel-exhaust particles. Typical HAAs have been reported to induce carcinogenicity and metabolic disturbances, but how these hazardous compounds interfere with metabolic networks by regulating metabolic pathways and fingerprinting signature metabolites as biomarkers remains ambiguous. We developed an advanced strategy that adopted chemical isotope labeling ultrahigh-performance liquid chromatography coupled to quadrupole-Orbitrap high-resolution mass spectrometry for urinary nontargeted metabolomics analysis to gain new insight into in vivo physiological responses stimulated by exposure to typical HAAs. Rats were orally administered with a single dose of 2-amino-1-methyl-6-phenylimidazo[4,5- b ]pyridine (PhIP) or 2-amino-3,8-dimethylimidazo[4,5- f ]quinoxaline (MeIQx) (1 and 10 mg/kg bw) and their D 3 -isotopic compounds, respectively, and urine samples were then continuously collected within 36 h. Metabolomics data were acquired and processed by classical multivariate statistical analysis, while urinary metabolites were further identified and characterized according to mass spectrometric fragmentation rules, time- and dose-dependent profiles, and calibration of synthesized standards. We monitored 23 and 37 urinary metabolites as the biotransformation products of PhIP and MeIQx, respectively, and first identified demethylated metabolites of PhIP, tentatively named 2-amino-6-phenylimidazo[4,5- b ]pyridine, and dihydroxylation products of classical HAAs as short-term biomarkers of exposure to further unravel the metabolic networks. In addition, our findings revealed that both HAAs significantly disturb histidine metabolism, arginine and proline metabolism, tryptophan metabolism, pyrimidine metabolism, tricarboxylic acid cycle, etc. Furthermore, we found that histamine, methionine, alanine, and 4-guanidinobutanoic acid could be considered potential characteristic biomarkers for the oncogenicity or carcinogenicity of both PhIP and MeIQx and screened their specific key pivotal metabolites. The current metabolomics approach is applicable in mapping updated urinary metabolic fingerprints and identifying potential specific biomarkers for HAAs-induced early tumorigenesis. [Display omitted] • We firstly identified N1-demethylated biotransformation products of PhIP. • We provided updated evidence for unraveling metabolic networks of HAAs in vivo. • We innovatively mapped urinary metabolic fingerprints from the exposure to HAAs. • We discovered amino acid metabolic pathways significantly affected by HAAs. • Potential characteristic biomarkers for the carcinogenicity of HAAs were screened. [ABSTRACT FROM AUTHOR]

[Display omitted] • Five modelling approaches are combined to construct a reasonable 3D structure of BaAADC. • The dynamic behaviour of BaAADC at high temperatures is demonstrated by comparative molecular dynamics simulations. • Dynamics calculations identify a range of highly flexible residues in BaAADC. • Salt bridge analysis provides information on thermally unstable ion pairs that can be used for further modifications. • This study reveals the mechanism of poor heat resistance of BaAADC for the first time at the molecular level. As an excellent biocatalyst, aromatic l -amino acid decarboxylase from Bacillus atrophaeus (Ba AADC) catalyzes the production of various vital aromatic biogenic amines. However, its weak heat resistance makes Ba AADC unsuitable for industrial production. Here, we generated the three-dimensional structure of Ba AADC and used molecular dynamics simulations to investigate the dynamic behavior of Ba AADC at different temperatures (303–343 K) to investigate the association between its thermal stability and internal residues. We have shown that the natural structure of Ba AADC is altered at high temperatures, with more striking alterations in secondary structure at the active site, fewer internal hydrogen bonding, and greater amino acid flexibility in the active pocket. Based on the root mean square fluctuations, the residues ASN46, GLU54, ALA113, ASP324, VAL329, and GLU332 were confirmed to be the most flexible. Salt bridge analysis revealed ion pairs ASP182-ARG197, ASP299-ARG347, GLU121-ARG344, GLU326-ARG316, GLU337-ARG316, GLU341-ARG347, and GLU470-ARG427 were partially responsible for the inactivation of Ba AADC at high temperatures. In addition, strategies to improve the thermostability of Ba AADC were discussed. This research might provide light on the development and modification of thermostable Ba AADC. [ABSTRACT FROM AUTHOR]

In this work, the effect of cyclic anaerobic/aerobic conditions on the biodegradative capability of the mixed microbial culture for the azo dye Acid Red 18 was investigated in the sequencing batch reactors. For this purpose, five anaerobic/aerobic sequencing batch reactors were operated under the same operation conditions at different anaerobic/aerobic reaction times. The whole reaction time was 22-h with anaerobic/aerobic periods of 6/16, 10/12, 14/8, 18/4 and 22/0 (h/h) in An/ASBR1 to 5, respectively. The results of this study indicated that the increase in the duration of the anaerobic phase had no significant effect on COD removal and sludge characteristics in all reactors except full anaerobic conditions. Increase in duration of anaerobic phases (6 to 22 hour) caused increase in the averages of dye removal efficiencies (36 to 96%) and decrease in oxidation-reduction potential (40 to -188 mV). The kinetics data of dye removal showed that the increase in duration of anaerobic phases caused increase in first-order kinetic rate constants (2.4×10-2 to 25×10-2 h-1). HPLC analysis indicated that metabolites formed during anaerobic phases were metabolized aerobically and formed less aromatic, more polar compounds. In addition, decrease in duration of aeration phases caused decrease the removal of metabolites during these phases. [ABSTRACT FROM AUTHOR]

In this work, three aromatic amines (p-toluidine, p-nitroaniline and p-chloroaniline) were chosen as bases for the repatriation of some nonionic polyesters. These amines were ethoxylated with different total number of ethylene oxide units 6, 12, 18. The prepared ethoxylated amine diols were polyesterified with maleic anhydride and polypropylene oxide polyethylene oxide block copolymers in polyesterification reaction. The demulsification efficiency of these demulsifiers was investigated using the bottle test. The effects of the molecular weight, concentration, asphaltene content, water content, Hydrophile Lipophile Balance (HLB) and temperature on the demulsification efficiency were investigated. The surface active properties were correlated with their demulsification efficiency. It was found that, NAE 18 D gave the best result in the demulsification process. The demulsification efficiency was discussed on the light of surface active properties, interfacial tension and the factors affecting the demulsification. The surface-active properties of the prepared demulsifiers were measured at 60 °C. [ABSTRACT FROM AUTHOR]

Clothes may contain a large range of chemical additives and other toxic substances, which may eventually pose a significant risk to human health. Since they are associated with pigments, polychlorinated biphenyls (PCBs) may be especially relevant. On the other hand, infants are very sensitive to chemical exposure and they may wear some contact and colored textiles for a prolonged time. Consequently, a specific human health risk assessment is required. This preliminary study was aimed at analyzing the concentrations of PCBs in ten bodysuits purchased in on-line stores and local retailers. The concentrations of 12 dioxin-like and 8 non-dioxin-like PCB congeners were determined by gas chromatography coupled to high resolution mass spectrometry, with detection limits ranging between 0.01 and 0.13 pg/g. The dermal absorption to PCBs of children at different ages (6 months, 1 year and 3 years old) was estimated, and the non-cancer and cancer risks were evaluated. Total levels of PCBs ranged from 74.2 to 412 pg/g, with a mean TEQ concentration of 13.4 pg WHO-TEQ/kg. Bodysuits made of organic cotton presented a total mean PCB concentration substantially lower than clothes made of regular cotton (11.0 vs. 15.8 pg WHO-TEQ/kg). The dermal absorption to PCBs for infants was calculated in around 3·10−5 pg WHO-TEQ/kg·day, regardless the age. This value is > 10,000-fold lower than the dietary intake of PCBs, either through breastfeeding or food consumption. Furthermore, this exposure value would not pose any health risks for the infants wearing those bodysuits. Anyhow, as it is a very preliminary study, this should be confirmed by analyzing larger sets of textile samples. Further investigations should be also focused on the co-occurrence of PCBs and other toxic chemicals (i.e., formaldehyde, bisphenols and aromatic amines) in infant clothes. [Display omitted] • Children's bodysuits may contain traces of polychlorinated biphenyls (PCBs). • Organic cotton clothes showed lower levels of PCBs than items made of regular cotton. • Dermal absorption of PCBs through clothing is much lower than their dietary intake. [ABSTRACT FROM AUTHOR]

This study reports a deep eutectic solvent based dispersive liquid-liquid microextraction (DES-DLLME) to extract aromatic amines (4-chloroaniline, 3-nitroaniline, 2-naphtylamine) in environmental water samples before their HPLC-UV determination. The hydrophobic deep eutectic solvent (DES) was prepared by mixing bis(2-ethylhexyl) phosphate (BEHP) as a hydrogen bond acceptor and phenol as a hydrogen bond donor. Affecting factors on the extraction of the aromatic amines were investigated and optimized. Optimum conditions were: DES type: BHHP-Ph ratio: 1 to 2; pH of solution: 8.0; DES volume: 80 µL, salt amount: 10% (w/v). Under optimum conditions, the developed method showed a wide linear range of 0.2–200 µg L−1 (R2 ≥ 0.99) with satisfactory recoveries (≥90.0%). The limit of detections (LODs) and limit of quantifications (LOQs) were in the range of 0.07–0.17 µg L−1 and 0.2–0.5 µg L−1, respectively. The enrichment factors were 170, 180 and 190 for 4-chloroaninile, 3-nitroaniline, 2-naphtylamine, respectively. Based on obtained results, the proposed method is straightforward, efficient, sensitive, and eco-friendly for the extracting and determining of the aromatic amines in environmental water samples. [ABSTRACT FROM AUTHOR]

The real-time textile dyes wastewater contains hazardous and recalcitrant chemicals that are difficult to degrade by conventional methods. Such pollutants, when released without proper treatment into the environment, impact water quality and usage. Hence, the textile dye effluent is considered a severe environmental pollutant. It contains mixed contaminants like dyes, sodium bicarbonate, acetic acid. The physico-chemical treatment of these wastewaters produces a large amount of sludge and costly. Acceptance of technology by the industry mandates that it should be efficient, cost-effective and the treated water is safe for reuse. A sequential anaerobic-aerobic plant-microbe system with acclimatized microorganisms and vetiver plants, was evaluated at a pilot-scale on-site. At the end of the sequential process, decolorization and total aromatic amine (TAA) removal were 78.8% and 69.2% respectively. Analysis of the treated water at various stages using Fourier Transform Infrared (FTIR), High Performance Liquid Chromatography (HPLC)) Gas Chromatography-Mass Spectrometry (GC-MS) Liquid Chromatography-Mass Spectrometry (LC-MS) indicated that the dyes were decolourized and the aromatic amine intermediates formed were degraded to give aliphatic compounds. Scanning Electron Microscope (SEM) and Atomic Force Microscopy (AFM) analysis showed interaction of microbe with the roots of vetiver plants. Toxicity analysis with zebrafish indicated the removal of toxins and teratogens. • Pilot scale plant-microbe sequential anaerobic – aerobic treatment demonstrated. • Real-time textile industry wastewaters treated. • The HRT optimized to 28 h. • Degradation of mixture of dyes and other pollutants observed. • Zebrafish embryos showed less teratogenic effects in the treated water. [ABSTRACT FROM AUTHOR]

Aromatic amines, the widely used raw materials in industry, cause long-term exposure to human bodies. They can be metabolized by cytochrome P450 enzymes to form active electrophilic compounds, which will potentially react with nucleophilic DNA to exert carcinogenesis. The short lifetime and versatility of the oxidant (a high-valent iron (IV)-oxo species, compound I) of P450 enzymes prompts us to use theoretical methods to investigate the metabolism of aromatic amines. In this work, the density functional theory (DFT) has been employed to simulate the hydroxylation metabolism through H-abstraction and to calculate the activation energy of this reaction for 28 aromatic amines. The results indicate that the steric effects, inductive effects and conjugative effects greatly contribute to the metabolism activity of the chemicals. The further correlation reveals that the dissociation energy of -NH 2 (BDE N-H) can successfully predict the time-consuming calculated activation energy (R 2 for aromatic and heteroaromatic amines are 0.93 and 0.86, respectively), so BDE N-H can be taken as a key parameter to characterize the relative stability of aromatic amines in P450 enzymes and further to quickly assess their potential toxicity. The validation results prove such relationship has good statistical performance (q cv 2 for aromatic and heteroaromatic amines are 0.95 and 0.90, respectively) and can be used to other aromatic amines in the application domain, greatly reducing computational cost and providing useful support for experimental research. [Display omitted] • The N-hydroxylation of 28 aromatic amines mediated by P450s has been simulated. • The activation energies of H-abstraction (Δ Ε) have been calculated by DFT method. • The steric, inductive and conjugative effects contribute to the metabolism reactivity. • A linear correlation between the bond energy (BDE N-H) and Δ Ε has been built. • The models can quickly predict the metabolism activity of aromatic amines. [ABSTRACT FROM AUTHOR]

The impact of different woodchips (beech, oak, pear, and apple) on the contents of heterocyclic aromatic amines (HAAs) and quality characteristics of smoked bacon was investigated. The results indicated that the contents of total HAAs and non-polar HAAs in beech- and oak-smoked bacon were lower than that in pear- and apple-smoked bacon (P < 0.05). There were no HAAs detectable in control (non-smoking) sample. The smoking process promoted the formation of free amino acids (FAA) in the smoked bacon. The total contents of FAA in beech- and oak-smoked bacon were higher than these in the pear- and apple-smoked bacons (P < 0.05). The beech-smoked bacon had the highest L *-value (P < 0.05), and oak-smoked bacon had the lowest thiobarbituric acid-reactive substance (TBARS) value and carbonyl content (P < 0.05). Additionally, woodchip types had no significant influence on a *-value, b *-value, moisture content, a w , T 20 , T 21 and T 22 (P > 0.05). PCA of the HAA contents and quality characteristics could effectively differentiate that were unsmoked and smoked bacon. Therefore, woodchip types had a great influence on HAA contents and quality of smoked bacon. • Woodchip type had a significant impact on HAA contents and quality in bacon. • Non-polar HAA contents were higher than polar HAA contents in bacon samples. • HAA contents in pear- and apple-smoked bacon were higher than in other samples. • The beech- and oak-smoked bacon had similar HAA content and quality characteristics. [ABSTRACT FROM AUTHOR]

Highlights: [•] Increasing methylene groups in aryl amines results in higher cation–π interactions. [•] There is good correlation between proton affinities and Hammett’s parameters. [•] Hydrogen atom of ammonium group is responsible for making cation–π interactions. [Copyright &y& Elsevier]

• Highly dispersed Ag NPs on carbon decorated hollow TiO2 with high catalytic activity. • The complete degradation of phenolic pollutants under simulated solar light. • Ag/C-TiO2 exhibited efficient and selective hydrogenation of nitroaromatics to aromatic amines. • The possible degradation/hydrogenation mechanisms were proposed. The excellent photocatalytic degradation/catalytic reduction of phenolic pollutants still is a challenge. Here, we report a new silver/carbon co-decorated hollow TiO 2 photocatalyst (Ag/C-TiO 2) by depositing Ag NPs on the surface of carbon decorated hollow TiO 2 sphere. This preparation process mainly involves in the synthesis of CPS@TiO 2 template, the immobilization of silver ions, the preparation of carbon co-decorated hollow TiO 2 , and the formation of Ag/C-TiO 2 photocatalyst. The as-synthesized Ag/C-TiO 2 photocatalyst exhibits a complete removal (100%) of phenolic pollutants (phenol or 4-nitrophenol) under simulated sunlight due to the synergistic effect of silver decoration and carbon species. Notably, corresponding 4-aminophenol is achieved almost quantitatively towards the hydrogenation of 4-nitrophenol. Especially, the Ag/C-TiO 2 photocatalyst exhibits a good stability and recyclability towards the photocatalytic degradation/reduction of 4-NP. Therefore, this work presents a rational design concept of highly efficient photocatalysts for environmental remediation. [Display omitted] [ABSTRACT FROM AUTHOR]

In this article, the author discusses a research related to strategies for decolorizing high concentrations of methyl orange by using growing cells of Lactobacillus casei TISTR 1500. Topics discussed include batch, fed-batch, and continuous fermentation was used in the processing of methyl orange decolorization, methyl orange is an important commercial and anionic azo dye with good stability and special color characteristics, and azo dyes are carcinogens as they decompose to aromatic amines.

Highlights: [•] N–H bond dissociation enthalpies calculated for 42 mono-substituted anilines. [•] DFT/B3LYP and DFT/PBE0 results more reliable than SCC-DFTB ones. [•] Comparison of substituent effect in anilines with phenols and thiophenols. [•] Geometry-based descriptors of substituent effect investigated. [Copyright &y& Elsevier]

The present work is concerned with studying the effect of some new aliphatic and aromatic diamines as additives in combination with the effect of other parameters such as current density and temperature on the rate of electrodeposition, energy consumption, and morphology of nickel deposited from sulphate solutions. Current efficiency of Ni deposition ranged from 6·13 to 84·00% depending on the operating conditions while energy consumption ranged from 0·25 to 11·58 kWh kg-1 depending on the operating conditions. A scanning electron microscopy study revealed that from among the different amines examined, diphenyl amine gave the highest degree of deposit brightness. The mechanism of action of different amines has been discussed. Possible application of the present results in different electrometallurgical processes involving Ni deposition such as electrowinning, recovery of Ni from waste solutions, electroforming, electrorefining and electroplating was noted. [ABSTRACT FROM AUTHOR]

Abstract: In the field of dye industries, heterocyclic compounds can play the important role to synthesis the various acid and mordent dyes which can give the variety of shades to different fabrics. Here, new heterocyclic acid and mordent acid dyes were synthesized by the coupling of diazonium salt solution of different aromatic amines having acidic groups with derivatives of dihydrobenzofuran and the obtained heterocyclic acid dyes were analyzed by various spectral techniques and the dyeing assessment of all the dyes was evaluated on wool and silk fabrics and the dyeing of chrome pre-treated wool and silk fabrics showed better shades on mordented fabrics due to chrome complex and it shows good shades with excellent depth and level ness and the dyed fabrics showed excellent fastness properties. [Copyright &y& Elsevier]

Aromatic amines are environmental pollutants and represent one of the most important classes of industrial and natural chemicals. Some types of complex effluents containing these chemical species, mainly those originated from chemicals plants are not fully efficiently treated by conventional processes. In this work, the use of electrochemical technology through an electrolytic pilot scale flow reactor is considered for treatment of wastewater of a chemical industry manufacturer of antioxidant and anti-ozonant substances used in rubber. Experimental results showed that was possible to remove between 65% and 95% of apparent colour and chemical oxygen demand removal between 30 and 90% in 60 min of treatment, with energy consumption rate from 26 kWh m³ to 31 kWh m³. Absorbance, total organic carbon and toxicity analyses resulted in no formation of toxic by-products. The results suggest that the presented electrochemical process is a suitable method for treating this type of wastewater, mainly when pre-treated by aeration. [ABSTRACT FROM AUTHOR]

Copyright of Polimery is the property of Industrial Chemistry Research Institute and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The corrosion inhibitor efficiency of aromatic amines for mild steel in 0.5 M sulfuric acid (H2SO4) was investigated using polarization and weight-loss measurements. The results revealed that these inhibitors exhibit good corrosion inhibition even at a very low concentration. Polarization curves showed that all of the compounds are mixed-type inhibitors. The adsorption of inhibitors is found to obey the Langmuir isotherm. Molecular parameters that are directly related to the corrosion inhibition properties of any compound are investigated using the density functional theory (DFT) quantum chemical method. These results show that the electron pair on oxygen atoms of the nitro group are the preferred site for adsorption of these compounds on an iron surface. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Medical Mycology / Journal de Mycologie Médicale is the property of Elsevier B.V. and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Abstract: New voltammetric DNA biosensor based on a microcrystalline natural graphite–polystyrene composite film in the role of a transducer was used for the investigation of the interaction between model carcinogenic substance (2-aminofluorene; one of the most extensively studied examples of the aromatic amine class of carcinogens) and calf thymus double-stranded DNA (dsDNA). The layer of dsDNA immobilized at the electrode surface was utilized as a biocomponent responsive interface. The biosensor was characterized regarding the detection of DNA damage (induced by direct interaction with 2-aminofluorene) using square wave voltammetric responses of the guanine and adenine moieties and cyclic voltammetric responses of the anionic redox indicator [Fe(CN)6]4–/3– present in the solution. [Copyright &y& Elsevier]

In order to determine the residual aromatic compounds in electromagnetic shielding textiles, the followed pretreatment parameters should be clear and optimized: the pressure of rotary vacuum evaporator, water-bath vibration shake and the pH value of buffer solution. It is found that, when the pressure of rotary vacuum evaporator is 300 mbar, highest recovery of the aromatic amines and experiment efficiency will be gained. The investigation also points out that with waterbath vibration shaking and the pH value of buffer solution between 5.5 and 6.1 , relatively ideal detection results can be got. [ABSTRACT FROM AUTHOR]

Abstract: Potential biologically active derivatives of arylhydrazotriazole (3a–l) were prepared by the condensation reaction of diazonium salts using various aromatic amines (1a–l) and 1-(2,4-difluorophenyl)-2-(1H-1,2,4-triazol-1-yl) ethanones (2). The synthesized products were obtained in 75–85% yield. All the synthesized products were having good-excellent antifungal activity as compared with standard (Fluconazole and Ketoconazole) drugs. [Copyright &y& Elsevier]

We demonstrated a planar heterojunction organic photovoltaic (PHJ-OPV) device with open-circuit-voltage (Voc) of 1.03 V, utilizing bis(4-(N-(1-naphthyl)phenylamino) phenyl)fumaronitrile (NPAFN) as the donor material in combination with the conventional fullerene (C60) as the acceptor. Compared with conventional copper phthalocyanine (CuPC)/C60 PHJ-OPV, Voc increased 100%. Although the short-circuit-current was slightly reduced from 4.85 to 3.65 mA/cm², due to the lower absorption depth of NPAFN, the overall power conversion efficiency of our NPAFN-based OPV device was 1.97%, much higher than that of a typical CuPC-based device (1.31%). Besides, under forward bias (1.5V), red emission was observed from this PHJ-OPV, arising from the recombination from the non-doped red emitter, NPAFN. [ABSTRACT FROM AUTHOR]

Abstract: The nonlinear optical (NLO) properties of a series of anilines and N,N-dimethylanilines are studied with second-order Møller–Plesset perturbation theory (MP2). The effect of solvents on the calculated NLO properties is investigated by considering a wide range of solvent systems within the polarizable continuum model. In order to identify systems with high first-order hyperpolarizability, the effects of four basic variations to the molecules on the calculated NLO properties are studied. The modifications comprise changes to the donor strength (NH2 to N(CH3)2), changes to the acceptor strength (NO2, CN and CHO), variation of additional substituents (H, CH3, Br, OCH3), and changes in the conjugation length. It is found that the first-order hyperpolarizability increases when the compounds have N,N-dimethyl as donor, vinyl nitro group as acceptor at the 4-position, and a methoxy group as substituent at the 2-position. [Copyright &y& Elsevier]

Abstract: The addition-diketonization mechanism of aniline and phenylacetylene activated with O2, CuBr2 and 2,2,6,6-tetramethylpiperadine-1-oxyl (TEMPO) were elucidated at B3LYP/6-31G(d,p) level with Gaussian 03 package. It is found that the C–H bond scission bears the lowest energy barrier, but the barrier of the succedent H-shifting process is too large to overcome. However, TEMPO can accept the dissociated hydrogen atom, and the generated TEMPOH will aid the H-shifting process and the O–O breakage. It may be TEMPOH that makes the diketonization energetically favorable, rather than TEMPO. [ABSTRACT FROM AUTHOR]

New optically active aromatic poly(amide-imide)s (PAIs) were prepared from newly synthesized N,N?-(bicyclo[2,2,2]oct-7-ene-2,3,5,6-tetracrboxylic)-bis-L-valine diacid (4) via polycondensation with various aromatic diamines. The diacid (4) was synthesized by the condensation reaction of bicyclo[2,2,2]oct-7-ene-2,3,5,6-tetracarboxylic dianhydride (1) with L-valine (2) in acetic acid. All polymers were obtained in quantitative (high) yields with inherent viscosities of 0.24-0.36 dL/g. All of these polymers were highly organosoluble in solvents like N-methyl-2-pyrrolidone (NMP), dimethylformamide (DMF), N,N'-dimethylacetamide (DMAc) and dimethylsulfoxide (DMSO) at room temperature and were fully characterized by means of NMR spectroscopy, FTIR spectroscopy, elemental analyses, inherent viscosity, solubility test, specific rotation and thermal properties of the poly(amide-imide)s were investigated using TGA/DTG. [ABSTRACT FROM AUTHOR]

Abstract: Introduction: The combination of sodium hypochlorite (NaOCl) and chlorhexidine (CHX) results in the formation of a precipitate. In a previous study, we demonstrated the formation of 4-chloraniline (PCA) in the precipitate in an amount directly related to the concentration of NaOCl used. Aims and Methods: The aim of the present study was to use a diazotization technique to confirm the presence of an aromatic amine (like PCA) in the NaOCl/CHX precipitate and also in the 2.0% CHX at different temperatures (37°C and 45°C). Results: The results corroborated the presence of the aromatic amine in the precipitate and in the CHX at 45°C. Conclusions: Further investigations of the precipitate should address the bioavailability of PCA leaching out from dentin and its cytotoxicity. Until the precipitate is studied further, it would appear prudent to minimize its formation. [Copyright &y& Elsevier]

In this paper, a H202 biosensor was propose~1. At first, an organic conductive material, 3,4,9,1 0-perylenetetracarboxylic acid- toluidine blue (P1'ATB), was synthesized by 3,4,9,10-perylenetetracarboxylic dianhydride and toluidine blue. Then the prepared PTATB was dispersed into Ti02 solution and dropped on a glassy carbon electrode to form a stable Ti02-PTATB composite film with efficient redox activity. Later, gold nanoparticles (GNPs) were carbonylated by O-carboxymethyl chitosan (CMCS) to obtain functionalized gold nanoparticles (CMCS-GNPs), which were adsorbed on the Ti02-PTATB film with positive charge via elec- trostatic interaction. Finally, hemoglobin, as a model enzyme, was covalently immobilized onto the electrode modified with CMCS-GNPs/Ti02-PTATB matrix to construct a new H202 biosensor. The proposed biosensor displays a high sensitivity, fast analytical time, and broader linear response to H202 in the range from 1.4 X lO6 to 1.6 X lO~ M with a limit of detection of 3.7 X lO~ M at 3 times the background noise. The apparent Michaelis-Menten constant (Ky) and the maximum current density (1'max) for the proposed biosensor were estimated to be 0.62 mM and 211 p~A/cm2, respectively. This work provided a new avenue for the electrochemical investigation of enzyme immobilization. [ABSTRACT FROM AUTHOR]