Variation Of Functional Groups Research Articles

SYNTHESIS, CHARACTERIZATION AND SKELETAL MUSCLE RELAXANT ACTIVITY FOR NOVEL [1,4]DIAZEPINO[2,3-G]QUINOXALINE DERIVATIVES

Novel [1,4]diazepino[2,3-g]quinoxaline derivatives 5a-5i were designed, synthesized and characterized by spectroscopic method and elemental analysis. The title compounds were screened for skeletal muscle relaxant. Among the synthesized analogs, compound 5g and compound 5h revealed significant skeletal muscle relaxant activity. The relationship between the functional group variation and the biological activity of the synthesized compounds is discussed.

Dual active 1, 4-dihydropyridine derivatives: Design, green synthesis and in vitro anti-cancer and anti-oxidant studies

The present work describes the design of 1,4-dihydropyridines (1,4-DHPs) with diverse variations in structural and functional groups. The physico-chemical properties and drug-like molecule nature evaluations were carried out using SWISSADME. A simple, economical, eco-friendly, water-mediated and Para-Toluene sulfonic acid catalysed multicomponent and one-pot synthetic method from nitroketene N, S- acetals (NMSM) and corresponding aldehydes has been developed. All compounds (6a-u and 13a-h) were subjected to in vitro assays against two important human cancer cell lines Viz. are Laryngeal carcinoma (Hep2) and Lung adenocarcinoma (A549) cells. The reduction level of DPPH (%) used to evaluate the anti-oxidant properties. The 1,4-DHP derivatives, 6o, 6u and 6l displayed the potent anti-cancer activity with IC50 value of 10 µM, 14 µM and 10 µM against the Hep2 and 8 µM, 9 µM and 50 µM against the A549 cells. Similarly, the anti-oxidant properties of 6o, 6l and 6u at a standard concentration of 50 µg, are found to be 70.12%, 63.90% and 59.57% respectively favours the 1,4-DHP derivatives dual activity potentials. The compounds, 6o and 6l found to be equivalent with standard drug, Doxorubicin.

Facile synthesis of sludge-based mesoporous carbon with flocculants: Effect of template on the synthetic behavior and improved phenol capture

Based on the self-assembly of materials and pyrolysis technology, the template-like method was developed to construct sewage sludge-based mesoporous carbons (SSMCs) by employing sewage sludge as precursor of carbon source, and three different flocculants including cationic polyacrylamide, anionic polyacrylamide and chitosan as template. During the preparation, the flocculant played roles of nucleation, pore formation and surface group modification. Different types of templates have similar self-assembly behavior with sludge particles and endow various properties of SSMCs. The appropriate template concentration strengthens the adsorption bridging effect between template and sludge, thereby promoting the more stable assemblies among precursors. Potential physicochemical changes during thermal evolution are recorded to reveal its preparation mechanism from the aspects of mass loss, variation of functional groups and component change, showing that obvious difference in thermal stability between sludge and flocculant lays a foundation for the mesoporous regeneration of SSMCs. Simultaneous improvement of surface acidic-alkaline group content, mesoporous structure and adsorption performance can be achieved by template-like method. Compared with other SSMCs, product prepared from anionic polyacrylamide displayed higher affinity to phenol due to its higher abundant amide group and π−π interactions. This work provides new insight into the development of utilization of excess sludge in sewage treatment plant.

Enhancing detection and characterization of lipids using charge manipulation in electrospray ionization-tandem mass spectrometry

Heightened awareness regarding the implication of disturbances in lipid metabolism with respect to prevalent human-related pathologies demands analytical techniques that provide unambiguous structural characterization and accurate quantitation of lipids in complex biological samples. The diversity in molecular structures of lipids along with their wide range of concentrations in biological matrices present formidable analytical challenges. Modern mass spectrometry (MS) offers an unprecedented level of analytical power in lipid analysis, as many advancements in the field of lipidomics have been facilitated through novel applications of and developments in electrospray ionization tandem mass spectrometry (ESI-MS/MS). ESI allows for the formation of intact lipid ions with little to no fragmentation and has become widely used in contemporary lipidomics experiments due to its sensitivity, reproducibility, and compatibility with condensed-phase modes of separation, such as liquid chromatography (LC). Owing to variations in lipid functional groups, ESI enables partial chemical separation of the lipidome, yet the preferred ion-type is not always formed, impacting lipid detection, characterization, and quantitation. Moreover, conventional ESI-MS/MS approaches often fail to expose diverse subtle structural features like the sites of unsaturation in fatty acyl constituents or acyl chain regiochemistry along the glycerol backbone, representing a significant challenge for ESI-MS/MS. To overcome these shortcomings, various charge manipulation strategies, including charge-switching, have been developed to transform ion-type and charge state, with aims of increasing sensitivity and selectivity of ESI-MS/MS approaches. Importantly, charge manipulation approaches afford enhanced ionization efficiency, improved mixture analysis performance, and access to informative fragmentation channels. Herein, we present a critical review of the current suite of solution-based and gas-phase strategies for the manipulation of lipid ion charge and type relevant to ESI-MS/MS.

Analysis of intermolecular interactions in homologous molecular crystals of energetic materials

Crystal packing modes determine the energy and safety performance of energetic materials (EMs) to some extent. To deepen the understanding of the intermolecular interactions in the crystal packings, the homologous molecular crystals of energetic materials were first defined according to the packing similarities in this study, and four groups of energetic homologous crystals with the same packing structures were found from the large experimentally available data. Several computational approaches were employed to comparatively probe the intermolecular interactions at molecular and crystal levels. The results of the analysis show that the common organic skeleton of two molecular conformations in each homologous packing structure remains the same or becomes mirror-symmetrical with a minor variation of functional groups, resulting in the local change of molecular electrostatic potentials, while the overall distribution of electrostatic potentials can be largely maintained. Compared with the other groups of homologous crystals, interestingly, the differences in intermolecular interactions in Group 4 are relatively large according to two-dimensional fingerprint plots and energy frameworks, indicating that the crystal packing of energetic materials is predominately caused by some types of intermolecular interactions. The results reported here are expected to inspire the constructions of energetic crystals with specific packing modes to improve performances, such as a minor modification to the molecular structure while keeping original crystal packing style. The homologous molecular crystals in energetic materials were first proposed based on the packing similarities to comparatively explore the intermolecular interactions in the same packing structures, with the goal of improving the understanding of crystal construction of energetic materials with specific packing modes.

Synthesis and characterization of iron oxide superparticles with various polymers

Iron oxide superparticles referring to a cluster of smaller nanoparticles have recently attracted much attention because of their enhanced magnetic moments but maintaining superparamagnetic behavior. In this study, iron oxide superparticles have been synthesized using a solvothermal method in the presence of six different polymers (e.g., sodium polyacrylate, pectin sodium alginate, chitosan oligosaccharides, polyethylene glycol, and polyvinylpyrrolidine). The functional group variation in these polymers affected their interactions with precursor iron ions, and subsequently influenced crystalline grain sizes within superparticles and their magnetic properties. These superparticles were extensively characterized by transmission electron microscopy, dynamic light scattering, x-ray diffraction, Fourier transform infrared spectroscopy, and vibrating sample magnetometry.

Improving the surface insulating performance of epoxy resin/Al 2 O 3 composite materials by extending chain of liquid epoxy resin with Me‐THPA

Basin-type insulators are made by epoxy resin composite materials. Curing defects are easily formed in basin-type insulators, and degrade their insulating performances. High curing exothermic rates of epoxy resin composite materials have deemed as the main cause of curing defects formation. In this study, methyl tetrahydrophthalic anhydride (Me-THPA) was used to extend the molecular chain of liquid epoxy resin to prepare epoxy resin composite materials with low curing exothermic rates. Curing exothermic properties, molecular weight distribution, curing stress, microstructures, and surface flashover characteristics of the composite materials were investigated. The results showed that chain-extended epoxy resin had low curing exothermic rates. The curing stress of the chain-extended epoxy resin composite materials was small. The curing defects forming in the composite materials were inhibited. Negative DC surface flashover characteristics of these composite materials were improved. Furthermore, variation of functional groups of the composite materials was studied before and after surface flashover tests. Results showed that the content of carbon–oxygen single bonds (–C–O) in the chain-extended epoxy resin composite materials was observed to decrease. The –C–O bonds also affect the voltage withstand capability of the epoxy resin composite materials.

Variation of gas phase combustion properties of complex fuels during vaporization: Comparison for distillation and droplet scenarios

Surrogate mixtures for modeling real fuels are formulated based on gaseous combustion property targets and liquid physical properties. A batch distillation model was developed to evaluate the vaporization characteristics of some existing surrogates for Jet-A. Chinese aviation fuel RP-3 was then used as a target to experimentally obtain distillation curves and variation of chemical functional groups. A 24-component surrogate was formulated mainly to capture the distillation behavior of RP-3. This surrogate was then used in two droplet vaporization models (Finite Thermal Conductivity/Finite Diffusivity (FTC/FD), Infinite Thermal Conductivity/Infinite Diffusivity (ITC/ID)) to investigate the effects of preferential vaporization on gaseous combustion properties of a complex real fuel. The results obtained from FTC/FD and ITC/ID provide regional bounds for droplets in a vaporizing spray. Four combustion property targets (Molecular Weight (MW), Hydrogen to Carbon ratio (H/C), Derived Cetane Number (DCN) and Threshold Sooting Index (TSI)) were employed as indicators of gas combustion properties. It was found that due to a wide distribution of compounds’ volatility, gaseous combustion properties vary significantly during droplet vaporization. The results suggest development of vaporization models that well capture preferential vaporization of a target real fuel for further spray modeling.

Proton uptake behaviors of organic and inorganic matters in biochars prepared under different pyrolytic temperatures

As an important part of biochar, surface functional group is the key interface between biochars and other phases, as well as an essential source of biochar's alkalinity and buffer abilities. However, due to the intricate organic and inorganic structures within biochars, the contribution from organic and inorganic matters to the functional groups remains unknown. In this work, the proton uptake curves were applied to study the functional groups of biochars via titration. Pine needle (PN) derived biochars with low inorganic content was selected for analyzing the organic functional groups variation under different pyrolysis temperatures. While rice straw (RS) derived biochars and the double-acid treated rice straw (DRS) derived biochars were compared for understanding the contributions from inorganic matters. The results indicate that the sorption behavior of proton onto biochars is surface adsorption, and the functional groups variation within PN biochars keeps consistent with reactions happened during pyrolysis. The inorganic matters within RS biochars contributed significantly to the buffering ability of biochars, and it is noteworthy to find that the contribution of inorganic matters of RS350, RS500, and RS700 on the total proton uptake stabilized at 67%, 84%, and 84% in the pH range of 2–8, respectively. As far as we know, this is the first report on separating the proton uptake ability of the organic and inorganic matters for biochars. The study on the interaction between biochars and proton will improve the estimation of the fate of ionizable pollutants, and the differentiation on the organic and inorganic matter contributions would benefit the understanding of biochar organic structures and inorganic structures.

Effect of Water-immersion and Air-drying Period on Spontaneous Combustion Characteristics for Long-flame Coal

ABSTRACT During the mining of coal seam groups, the physical and chemical properties of the residual coal in goaf will be changed after undergoing water leaching and air-drying, affecting the oxidation characteristics of the coal. To examine the effect of the water immersion and air-drying times on the oxidative combustion characteristics of long-flame coal, this paper uses thermal gravimetric (TG) analysis and infrared spectral analysis to analyze coal samples with different immersion and air-drying times. The change in activation energy (AE), which is associated with the change in the functional groups, was analyzed for the coal-oxygen chain reaction process under coal immersion and air-drying conditions. The results show that coal samples soaked in air-dried for 10 days after water for 20 days have a lower AE (39.14 kJ/mol) than coal samples that underwent other treatment times and have a higher oxygen absorption rate and a higher tendency to undergo spontaneous combustion. According to the TG-DSC test, a range of weight loss and exothermic strengths are observed during the longest immersion and air-drying times. Additionally, during the longest immersion and air-drying times, the variations in the different functional groups are more obvious, the aliphatic hydrocarbon chain breaks and the coal rank is lower. The period of immersion and air-drying can change the spontaneous combustion oxidation characteristics of coal. After being soaked in water for 20 days and air-dried for 10 days, the coal sample was looser and the chain reaction process was accelerated, which promoted the oxidation and spontaneous combustion of coal.

UV-B priming enhances specific secondary metabolites in Oryza sativa (L.) empowering to encounter diverse abiotic stresses

Plants are exposed to various abiotic stresses and there exists sophisticated mechanisms within them for tolerating these stresses. The present study clearly revealed the efficacy of UV-B priming at both seed and seedling stage in tolerant (Kanchana) and sensitive (Aiswarya) rice varieties, to tolerate UV-B stress, polyethylene glycol-6000 (PEG) and NaCl stresses. Increase in UV stress specific characters such as accumulation of UV absorbing compounds [flavonoids (242–368%) and anthocyanin (367–386%) content],increased activity of phenylalanine ammonia lyase (116–210%) and increased leaf cuticular wax content (382–403%) was observed in UV-B primed seedlings of rice subjected to UV-B, NaCl and PEG stresses. The increase in the levels shown as percent increase were highest in seedlings subjected to UV-B stress followed by NaCl and PEG stresses. The influence of priming imprints was more effective in seeds and seedlings of the tolerant rice variety (Kanchana) than the sensitive variety (Aiswarya). Functional groups variation in wax content was more prominent in PEG stress conditions than UV-B and NaCl stresses and it was mainly observed in Aiswarya than in Kanchana. Additionally our results suggests the UV-priming mediated enhancement of the stress tolerance potential of a tolerant variety seems to be more successful than the sensitive variety.

Insight into papermaking characteristics of D0EPD1-bleached soda, soda-AQ and kraft pulps of citronella grass (Cymbopogon winterianus Jowitt)

Grasses have emerged as potential alternative raw materials which can replace wood for pulp and paper products. Various species of grasses have been explored previously for pulp and paper production. This study is aimed to investigate pulp and papermaking characteristics of a grass species namely Cymbopogon winterianus Jowitt which is commonly known as citronella grass. This grass was subjected to proximate chemical characterisation; fibre morphology analysis; soda, soda-AQ (soda-anthraquinone), and kraft pulping; elemental chlorine free bleaching using D0EPD1 (D = ClO2 in acidic medium; EP = alkaline extraction with addition of H2O2; 0 and 1 = initial and final stage) sequence; and evaluation of physical strength properties of paper hand sheets. The pulp and paper hand sheets were also examined through SEM (scanning electron microscope) and FTIR (Fourier-transform infrared) spectroscopy to observe the structural and functional group variations. The proximate chemical analysis of citronella grass was found superior in terms of α-cellulose (38.10%), pentosans (22.30%) and alkali solubility (28.20%) while inferior in terms of ash (8.20%), lignin (25.10%) and alcohol benzene solubility (6.31%) with respect to some other grass species used for pulp and papermaking. Fibre length (0.69–0.74 mm) and fibre width (13.8–15.1 μm) were also comparable to other grass species. Brown pulp characteristics such as screened yield (44.67%), brightness (~24 %ISO) and kappa number (~20) revealed superiority of soda-AQ pulping among all the pulping processes while the kraft pulp exhibited the highest brightness (83.05 %ISO) and intrinsic viscosity (17.6 cP) after D0EPD1 bleaching. Tear index, tensile index and burst index of paper hand sheets obtained from bleaching of soda-AQ and kraft pulps were almost similar but higher to that of bleached soda pulp. The citronella grass was found suitable for producing writing and printing grade paper based on processes and optimised parameters described in this study.

Responses of phytoplankton functional groups to environmental factors in the Pearl River, South China.

The variations of phytoplankton functional groups and their correlation with environmental factors, as well as the applicability of phytoplankton functional groups to serve as biological water quality indicator in the Pearl River, South China, were studied in the present study. A total of 96 samples were collected and divided into 21 functional groups from September 2016 to July 2017. The phytoplankton functional groups P and G were dominant during the investigation, and their biomass contributing was ranged 0.06 to 89.07%, the average 30.73%, and ranged 1.47 to 62.40%, the average 9.33% of the total biomass, respectively. The results showed environmental estrogens-BPA (bisphenol A), E2 (17β-estradiol), E1 (estrone), 4-t-OP (4-tert-octylphenol), 4-NP (nonylphenol), TCS (triclosan), and TCC (triclocarban)-in the Pearl River were significantly different, and with average values of 269.30ngL-1, 2.76ngL-1, 4.24ngL-1, 53.68ngL-1, 952.72ngL-1, 16.79ngL-1, and 8.61ngL-1, respectively. This was likely responsible for the differences in the phytoplankton functional groups. We observed positive correlations between P and A, and G and J. Functional groups P biomass decreased significantly with functional groups LM increased, and functional groups M and J with X2. We found positive correlations between functional group G and concentrations of E1 and TCC; functional group A and total nitrogen (TN), 4-NP, 4-t-OP, and E2; functional groups LM and L1 and total suspended particles, BPA, and TCS; and functional group G and negative total phosphorus (TP), pH, and TCS. The study showed that TN, TP, and the environmental estrogens in the aquatic ecosystems were correlation with phytoplankton functional groups type, and affected the ecological balance in aquatic environments.

Explanation of anomalous rate capability enhancement by manganese oxide incorporation in carbon nanofiber electrodes for electrochemical capacitors

Electrochemical capacitors (ECs) can provide ultra-long cycle life and ultra-fast energy delivery, characteristics which most battery technologies lack. Making composites out of carbon and pseudocapacitive materials is a popular strategy directed on narrowing the gap in energy density with regard to batteries. Usually, the incorporation of pseudocapacitive materials leads to a decrease in power performance compared to a pure carbon matrix, due to inferior electrical conductivity. This work, however, presents significant improvement in rate capability demonstrated by a composite electrode containing carbon nanofibers (NCNF) and manganese oxides (MnO2). The NCNF/MnO2 is prepared with a common method through the reaction with permanganate. The material has excellent performance metrics, especially a 78.2% rate capability (capacitance retention at 15 A g−1 relative to 0.5 A g−1), more than 10 times that for the NCNF carbon matrix. The exceptional enhancement can be explained by the development of micropores and surface area of NCNF, thus alleviating the “pore starvation” issue, and surface functional groups variation that enhances capacitive performance. This work highlights the importance of paying attention to the modification of carbon substrate when investigating carbon composite electrodes e.g. carbon/MnO2 networks.

Synthesis, Characterization & Antimicrobial Activities of New Isoxazole Substituted Mannich and Schiff Bases of 5-Nitroisatin Analogs

A sequence of new isoxazole substituted Schiff base and Mannich base of 5-nitroisatin are synthesized by a multi-step synthesis from 5-nitroisatin. Whole synthesized analogs were characterized using IR, NMR, Mass spectroscopy and microanalyses. All the Schiff and Mannich bases were tested for their antimicrobial potencies against some human pathogenic microorganism using agar well diffusion technique. The relationship between the biological activity and the functional group variation of the Schiff and Mannich bases were analyzed. Standard ciprofloxacin and ketoconazole were used to compare the antimicrobial activities of novel isatin coupled isoxazole derivatives.

Corncob-derived activated carbon for roxarsone removal from aqueous solution: isotherms, kinetics, and mechanism.

In this study, the adsorption of roxarsone (ROX) onto corncob-derived activated carbon (AC) was optimized using response surface methodology (RSM). Following this, the AC was comprehensively characterized by FT-IR, SEM, and EDS analysis. The results showed that the highest ROX adsorption efficiency of 304.34mg/g was obtained at the contact time of 262min, initial pH of 2.5, adsorbent dosage of 0.4g/L, and initial concentration of 240mg/L. Besides, it was found that the adsorption equilibrium data was fitted well to the Langmuir and Sips isotherm models. The thermodynamic parameters (e.g., ΔG, ΔH, and ΔS) revealed the spontaneous and exothermic nature of ROX adsorption. As indicated by pseudo second-order kinetics model, the adsorption of ROX onto AC could be achieved through the hydrogen bond, π-π adsorbate-adsorbent interaction, and electrostatic interaction between AC surface functional group and molecular species variations of ROX at different pH values. Overall, it can be concluded that corncob-derived AC is an alternative option for removing ROX from aqueous solution.

Acid and alkali resistance of Acrylic polyurethane/R‐SiO2 nanocomposite coating

AbstractThe purpose of this study is to assess the influence of R‐SiO2 nanoparticles on acid and alkali resistance of acrylic polyurethane coating. The resistance of the coatings with and without 2.5 wt.% R‐SiO2 nanoparticles in 5 % HCl solution and 5 % NaOH solution was investigated by monitoring the variations in functional groups of the coatings using IR spectroscopic analysis and the changes in their morphology using FE‐SEM analysis, as well as their weight loss analysis. The results showed that R‐SiO2 nanoparticles at content of 2.5 wt.% significantly increased the acid and alkali resistance of acrylic polyurethane coating. After 20 days of immersion in 5 % HCl solution and 5 % NaOH solution, the nanocomposite coating containing 2.5 % R‐SiO2 nanoparticles changed negligibly with a weight loss of about 1 % while the coating not containing R‐SiO2 nanoparticles was deformed seriously with a weight loss of about 3 %.

Hydrothermal co-carbonization of sewage sludge and high concentration phenolic wastewater for production of solid biofuel with increased calorific value

Hydrothermal carbonization has proven to be an effective method to convert sewage sludge into solid carbon-rich hydrochar, of which the high ash content is generally regarded as limiting factor for energy-related potential application. Hydrothermal co-carbonization of sewage sludge and high concentration phenolic wastewater was firstly investigated in this study as a scenario for production of clean solid biofuel with increased calorific value and decreased ash content, by means of polycondensation reactions between phenols and highly reactive intermediates of biopolymers in sewage sludge. Results showed that addition of phenolic wastewater into sewage sludge led to a substantial increase of hydrochar yield (1.83–31.11%) and higher heating value (1.01–10.01%) and a remarkable decrease of ash content (1.39–25.68%). The reaction temperature and residence time had a complicated impact on the contribution of phenol to hydrochar production. An increase in phenol mixing ratio was beneficial to the improvement of mass yield and higher heating value but showed a less influence on the reduction of ash content. The synergistic effects between phenols and sewage sludge on the production of solid biofuel were closely related to the phenolic species, which followed the order in the aspects of hydrochar yield increase and ash content decrease: phloroglucinol > p-nitrophenol > m-cresol > phenol. The changes of phenols content in liquid phase and variations of functional groups in hydrochars implied that phenols interacted with sewage sludge and incorporated into hydrochars during the hydrothermal co-carbonization. TG-DSC confirmed the improved combustion reactivity of the phenols-sludge-derived hydrochars.

Salmonella enterica Serovar Typhi exposure elicits deliberate physiological alterations and triggers the involvement of ubiquitin mediated proteolysis pathway in Caenorhabditis elegans

Involvement of several candidate immune regulatory players at transcriptomic levels during microbial interactions were reported by involving C. elegans as a model system for the past few years. In the present study, we have identified a wide range of phenotypical, physiological and biochemical alterations in C. elegans triggered due to S. Typhi infection using standard approaches. We performed several behavioural studies and molecular studies such as liquid-phase IEF, MALDI-MS and bioinformatics analyses. S. Typhi exerted a slow killing against C. elegans and prompted several phenotypical changes such as egg laying defects, pharyngeal arresting, and triggered functional group variations which were disclosed using FT-IR. Proteome analysis using liquid phase IEF and MALDI-ToF-Mass Spectrometry ended up with the identification of 123 proteins which contains human orthologs. Bioinformatics analysis of the MS identified proteins revealed the involvement of ubiquitination pathway which was then validated using immunoblotting. Extensive studies similar to our study with the utility of high-throughput OMICS technologies during host pathogen interactions may pave a way for the identification of biomarkers against bacterial diseases.

Structural characteristics and flammability of low-order coal pyrolysis semi-coke

This study focused on the effects of pyrolysis temperature on the structural characteristics and combustion properties of low rank coal. The combustion performance of semi-coke at different temperatures was studied by using low-temperature pyrolysis technology and non-isothermal thermogravimetric analysis. The variation of functional groups and carbon structure was quantitatively analyzed. The results show that the temperature has a significant effect on the semi-coke structure and flammability. In the middle and low temperature pyrolysis stage, the removal of water, volatile matter and functional groups is mainly carried out, and the degree of condensation and graphitization of carbon atoms is not obvious. The semi-coke performance with a pyrolysis temperature of 1023K is close to that of anthracite. The pyrolysis process is accompanied by the destruction of carbonaceous and the formation of mesopores, which affects the combustion performance. As the temperature increases, the flammability of the semi-coke is lowered, and the chemical structure of the semi-coke is a major factor affecting the flammability. The method of Coast-Redfern integration was used to calculate the kinetic parameters of the semi-coke. As the pyrolysis temperature increases, the activation energy of the combustion reaction increases, which is consistent with the trend of combustion performance change.