Elimination Mechanism Research Articles

Scalable Rhodaelectro-Catalyzed Expedient Access to Seven-Membered Azepino[3,2,1- hi ]indoles via [5 + 2] C–H/N–H Annulation

Scalable Rhodaelectro-Catalyzed Expedient Access to Seven-Membered Azepino[3,2,1- <i>hi</i> ]indoles via [5 + 2] C–H/N–H Annulation

Occurrence of polycyclic aromatic compounds and interdomain microbial communities in oilfield soils

Soil polycyclic aromatic compound (PAC) pollution as a result of petroleum exploitation has caused serious environmental problems. The unclear assembly and functional patterns of microorganisms in oilfield soils limits the understanding of microbial mechanisms for PAC elimination and health risk reduction. This study investigated the polycyclic aromatic hydrocarbons (PAHs) and substituted PAHs (SPAHs) occurrence, and their impact on the bacteria-archaea-fungi community diversity, co-occurrence network and functionality in the soil of an abandoned oilfield. The results showed that the PAC content in the oilfield ranged from 3429.03 μg kg−1 to 6070.89 μg kg−1, and risk assessment results suggested a potential cancer risk to children and adults. High molecular weight PAHs (98.9%) and SPAHs (1.0%) contributed to 99.9% of the toxic equivalent concentration. For microbial analysis, the abundantly detected degraders and unigenes indicated the microbial potential to mitigate pollutants and reduce health risks. Microbial abundance and diversity were found to be negatively correlated with health risk. The co-occurrence network analysis revealed nonrandom assembly patterns of the interdomain microbial communities, and species in the network exhibited strong positive connections (59%). The network demonstrated strong ecological linkages and was divided into five smaller coherent modules, in which the functional microbes were mainly involved in organic substance and mineral component degradation, biological electron transfer and nutrient cycle processes. The keystone species for maintaining microbial ecological functions included Marinobacter of bacteria and Neocosmospora of fungi. Additionally, benzo [g,h,i]pyrene, dibenz [a,h]anthracene, indeno [1,2,3-cd]perylene and total phosphorus were the key environmental factors driving the assembly and functional patterns of microbial communities under pollution stress. This work improves the knowledge of the functional pattern and environmental adaptation mechanisms of interdomain microbes, and provides valuable guidance for the further bioremediation of PAC-contaminated soils in oilfields.

Reduction the contamination of patulin during the brewing of apple cider and its characteristics

Patulin is one of the most significant food safety problems in fruit and derived products. The reduction of patulin contamination in food processing has always been the focus of research. In this study, nine yeast strains were applied for the brewing of apple cider and the fate of patulin was determined. In this process, the patulin contamination can be decreased by adsorption onto and degradation of yeast cells in the main fermentation (20.8–49.1%), as well as the adsorption removal during clarification (18.7–58%), inverted cans (21.3–31.4%) and aging (1.0–5.8%). Saccharomyces cerevisiae (1027) was selected to reveal the elimination mechanism of patulin in main fermentation. The decrease of patulin content was mainly due to degradation and the intracellular enzymes played a more important role than extracellular ones. In addition, the synthesis of enzymes was related to the induction of patulin. Furthermore, the degradation product of patulin in the main fermentation was identified as E-ascladiol, which is less toxic than patulin. Based on the representative strain of S. cerevisiae 1027, patulin contamination can be effectively eliminated during apple cider brewing. This study provides a new insight into eliminating patulin contamination in the brewing of apple cider.

Nɛ-(carboxymethyl)lysine, Available Lysine, and Volatile Compound Profile of Biscuits Enriched with Grape by-Product During Storage.

We investigated the changes in Nɛ-(carboxymethyl)lysine (CML) and available lysine content, antioxidant properties, volatiles, and oxidation products of biscuits enriched with grape by-product (GP), stored for six months under a modified atmosphere of 0%/30%/70% O2/CO2/N2 and in air. Fresh GP-formulated biscuits showed lower concentrations of CML (89%), available lysine (40%), and pyrazines (75%), but higher antioxidant capacities (~ sixfold), furans (12-fold), and lipid-derived compounds (three-fold) than the control. Although ~ 15% higher losses of Maillard-type volatiles were identified in the air atmosphere during storage, lipid oxidation was ~ 30% less pronounced in the modified atmosphere. A significant correlation of 0.994 between the reduction in CML and the available lysine suggest further CML reactions with the ɛ-NH2 group of amino acids. Significant correlations (of -0.550 to -0.980) between oxidation products, antioxidant capacities, and changes in CML content during storage suggest that these parameters might be involved in the CML elimination mechanism.

A constrained cooperative adaptive multi-population differential evolutionary algorithm for economic load dispatch problems

Many engineering optimization problems are characterized by large scale and complex constraints. High optimization efficiency and reliable constraint handling are two major challenges. The traditional optimization methods hard to obtain practical and feasible solutions in reasonable time. To get better solutions and enhance the global search capability, a constrained cooperative adaptive multi-population differential evolutionary (CCAM-PDE) algorithm is proposed in this paper. The main contributions of this paper are in three aspects. First, a hyperspace dynamic constraint handling region between feasible region and infeasible region is proposed. Second, according to the feasible rate of population, a “one to one” or “one to many” subpopulation generation scheme is adopted for improving the global searching ability. Third, the selection operation of differential evolution algorithm is replaced by the elimination mechanism through the constraint handling technology. Eight economic load dispatch problems and CEC2017 Benchmark test functions are used to testify the performance of the CCAM-PDE algorithm. The experimental results shown that the CCAM-PDE algorithm has a strong constraint-handling efficiency and better global searching ability, its search accuracy and the speed of convergence against the other state-of-the-art algorithms.

Transformation mechanism of carbamic acid elimination and hydrolysis reaction in microbial self-healing concrete

ABSTRACT Carbamic acid (NH2COOH) plays an important role in microbial induced carbonate precipitation. However, investigations on the reaction mechanisms of NH2COOH elimination and hydrolysis are still lacking. In this work, the transformation mechanism of NH2COOH elimination and hydrolysis in neutral and basic conditions was investigated by quantum chemical calculation. The results showed that NH2COOH mainly existed in the form of trans-NH2COOH configuration in the liquid phase at room temperature. In the neutral condition, the catalysis of NH3 or H2O could reduce the reaction energy barrier of NH2COOH elimination and hydrolysis, and NH2COOH tended to carry out the elimination reaction catalysed by NH3 to generate NH3 and CO2. In the basic condition, reaction energy barriers of NH2COOH elimination and hydrolysis increased and decreased significantly, respectively, indicating that the basic condition was unfavourable for the NH2COOH elimination reaction but rather favourable for the NH2COOH hydrolysis reaction. NH2COOH in the basic condition tended to carry out the hydrolysis reaction to generate NH3 and H2CO3. The transformation mechanism of NH2COOH elimination and hydrolysis in different conditions was examined in this work, which would provide the theoretical guidance for the better healing ability of microbial self-healing concrete in practical engineering.

High pressure-induced elimination of grain size softening in nanocrystalline metals: Grain boundary strengthening overwhelming reduction of intragranular dislocation storage ability

Recent experimental studies indicate that the yield strength of nanocrystalline (NC) metals under high hydrostatic pressure exhibits monotonous strengthening as the grain size decreases. In other words, the softening with decreasing grain size known as the inverse Hall–Petch (HP) behavior is eliminated by high hydrostatic pressure. To reveal the underlying mechanism of inverse HP elimination, here we propose pressure-dependent crystal plasticity constitutive models for both grain boundaries (GBs) and grain interiors (GIs) considering size-dependent intragranular dislocation storage. It is found that the elimination of inverse HP behaviors is facilitated by the hydrostatic pressure-induced GB strengthening and is hindered by GI softening attributed to the reduction of intragranular dislocation storage ability. The tension–compression asymmetry of the yield strength of NC metals becomes remarkable with decreasing grain size and eventually saturates as the grain size decreases down to several nanometers. Moreover, high hydrostatic pressure-induced suppression of GB plastic deformation relieves the shear localization and restricts the coalescence of microcracks and microvoids in adjacent grains with possible crack extension prohibited. Consequently, the ductility and fracture strength of NC metals are enhanced. Our results provide novel and fundamental insights for understanding high-pressure strengthening of NC metals and pave the way for the rational design and fabrication of NC metals of ultra-strength and ultra-ductility via GB engineering.

IMGT® Biocuration and Analysis of the Rhesus Monkey IG Loci.

The adaptive immune system, along with the innate immune system, are the two main biological processes that protect an organism from pathogens. The adaptive immune system is characterized by the specificity and extreme diversity of its antigen receptors. These antigen receptors are the immunoglobulins (IG) or antibodies of the B cells and the T cell receptors (TR) of the T cells. The IG are proteins that have a dual role in immunity: they recognize antigens and trigger elimination mechanisms, to rid the body of foreign cells. The synthesis of the immunoglobulin heavy and light chains requires gene rearrangements at the DNA level in the IGH, IGK, and IGL loci. The rhesus monkey (Macaca mulatta) is one of the most widely used nonhuman primate species in biomedical research. In this manuscript, we provide a thorough analysis of the three IG loci of the Mmul_10 assembly of rhesus monkey, integrating IMGT previously existing data. Detailed characterization of IG genes includes their localization and position in the loci, the determination of the allele functionality, and the description of the regulatory elements of their promoters as well as the sequences of the conventional recombination signals (RS). This complete annotation of the genomic IG loci of Mmul_10 assembly and the highly detailed IG gene characterization could be used as a model, in additional rhesus monkey assemblies, for the analysis of the IG allelic polymorphism and structural variation, which have been described in rhesus monkeys.

Grain boundary elimination by twinning and dislocation nucleation in front of intergranular crack tips in BCC iron

Grain boundary structures with high resistance to intergranular fracture are the target of grain boundary design. In this work, grain boundary elimination in front of crack tip is observed in two special bcc iron bicrystals through molecular dynamics simulations under mode I loading. Grain boundary elimination depends on crack advance direction and enhances resistance to intergranular fracture. Direction-dependent elimination leads to directional anisotropy of intergranular crack propagation. By analytical analysis and molecular dynamics simulation, grain boundary elimination is found to be attributed to the activities of twinning and dislocation. All twinning bands are formed by atomic slip along ordinary twinning direction, but all dislocations are nucleated by atomic slip along anti-twinning direction. Mechanisms of twinning formation and dislocation nucleation are revealed by calculating energy barriers of atomic slip and shear stress field. According to the mechanism of grain boundary elimination, conditions for grain boundary elimination are proposed to find all special grain boundaries. Results show that twist grain boundaries cannot be eliminated under mode I loading, while tilt grain boundaries with axes of 〈110〉 can. This work provides a good reference for grain boundary design.

Inactivation of Escherichia coli and somatic coliphage ΦX174 by oxidation of electrochemically produced Fe2+

Electrochemical ferrous iron (Fe2+) wastewater treatment is gaining momentum for treating municipal wastewater due to its decreasing costs, environmental friendliness and capacity for removal of a wide range of contaminants. Disinfection by iron electrocoagulation (Fe-EC) has been occasionally reported in full scale industrial applications, yet controversy remains regarding its underlying elimination mechanisms and kinetics. In this study, it was demonstrated that substantial inactivation can be achieved for Escherichia coli WR1 (5 log10) and somatic coliphage ΦX174 (2–3 log10). Electrochemically produced Fe2+ yielded similar inactivation as chemical Fe2+. Reactive oxygen species (ROS)-quenching experiments with TEMPOL confirmed that E. coli inactivation was related to the production of Fenton-like intermediates during Fe2+ oxidation. The observed E. coli disinfection kinetics could be mathematically related to Fe-EC current intensity using a Chick-Watson-like expression, in which the amperage is surrogate for the disinfectant's concentration. We hereby show that it is possible to mathematically predict disinfection based on applied Fe dosage and dosage speed. Phage ΦX174 inactivation could not be described in a similar way because at higher Fe dosages (>20 mg/l), little additional inactivation was observed. Also, ROS-quencher TEMPOL did not completely inhibit phage ΦX174 removal, suggesting that additional pathways are relevant for its elimination.

Numerical Analysis Growth Kinetics of Dendrite Tip during Laser Welding Nickel-Based Single-Crystal Superalloy Part I: Supersaturation-Driven Dendrite Growth

When three welding conditions, including welding configuration, welding speed and laser power, are sequentially altered, supersaturation of liquid aluminum is crystallography-dependently determined to limit growth kinetics of dendrite tip with decease of thermo-metallurgical factors for solidification cracking to salvage the weld properties during emerging laser welding repair of multicomponent nickel-based single-crystal superalloy. After comparing growth crystallography between right side and left side of weld, the distribution of supersaturation of liquid aluminum is axis- symmetrically developed by favorite (001)/[100] dendrite growth kinetics, while the distribution is nonaxisymmetrically developed by detrimental (001)/[110] dendrite growth kinetics. High heat input is inappropriately procured by either high laser power or slow welding speed to insidiously boost supersaturation of liquid aluminum, worsen alloying partition and solute copiousness, heterogeneously exacerbate morphology and size of dendrite growth, whereby stray grain formation is strongly produced. In order to ameliorate dendrite growth, low heat input is usefully rendered by either low laser power or high welding speed to attenuate supersaturation of liquid aluminum, narrow solidification temperature range and obviate dendrite tip undercooling alongside columnar interface in order to augment crack-resistant dendrite of epitaxial growth. The overall supersaturation of liquid aluminum is crystallography-dependent. During across whole melt-pool solidification interface, supersaturation of nonsymmetric (001)/[110] welding configuration is not as small as symmetric (001)/[100] welding configuration under well-controlled heat input, thereby fosters the kinetic factors for stray grain development to obstruct columnar dendrite and consequently weaken unidirectional morphology. It is crystallographically favorable for relief of supersaturation with axis- symmetrical dendrite growth. The mechanism of crack-vulnerable dendrite growth elimination through circumspect improvement of supersaturation-controlled growth kinetics is constructively proposed for feasible crackless rejuvenation of laser welding or laser cladding. The theoretical predictions are scrupulously supported by corroborative metallograph observation.

Organizational and legal mechanism of bio-medical emergencies management

This study aims to investigate the features of the concept and practical functioning of the prevention and elimination mechanism of bio-medical emergencies. The biblio-semantic and analytical methods of the set question research are used. The mechanisms of medical and biological character emergencies management depending on the goals of the tools used, as well as recommendations for optimization of this process, were described. According to the study results, we concluded that the provision of sustainable socio-economic society development should go side by side with the creation of a safe environment, ensuring the implementation of modern biosafety systems, and harmonizing with international legislation. There are all conditions for rapid changes in the epidemic situation in many countries with increasing anthropogenic impact on the environment, the resistance of infectious agents to chemotherapeutic and disinfectants, diversity of natural areas and biocoenosis, creating favorable conditions for the long-term existence of focal infections, identification of new forms, increased migration and international trade of food, as well as the spread of natural disasters and catastrophes. One of the ways to strengthen Ukraine's position may be to work on the creation of a risk management system in emergencies and bring legislation into conformity with international and EU legislation.

Symmetrical Resonance Mechanism of Elimination of Parasitic Torques of the Permanent Magnets Generator when Starting and Idling

. “Sticking” and vibrations of the stator of permanent magnet generators cause their increased wear, noise; also, their operation efficiency decreases. The article theoretically considers the possibility of eliminating the starting torque and oscillation of the rotation torque of the generator with permanent magnets without load due to mutual compensation of the interaction of coils with the field of permanent magnets at a certain symmetry of this field. The mentioned pheno-menon is called pi-resonance. For the specified class of model interaction potentials of the field of permanent magnets and coils, it has been shown that full compensation occurs with a certain number of coils (Ns) and magnets (Nr), while for other combinations of {Ns, Nr} the interaction is in the nature of oscillations. The corresponding tables for various classes of potentials are given which can serve as a basis for making design decisions when developing generators. Pi-resonance more probably takes place in the case of even number of stator coils and odd number of magnets, as well as with an increase in the number of stator coils. The cases of both one-sided and two-sided arrangement of the stator relative to the rotor are considered. Numerical modelling has shown that the pi-resonance is easily destroyed if the placement of magnets or coils is inaccurate, as well as by the magnet field potential symmetry breaking. An error in the angular arrangement of the coils of 1° can result in the appearance of a significant “cogging” of the rotor with energy of the order of the interaction energy of an isolated magnet – coil pair. A distortion of the symmetry of the potential yields a result similar in scale which is equivalent to the adding of a rump function with the amplitude of 10 % of the amplitude of the symmetric periodic potential. The patterns that have been discovered can be used in the design of efficient generators with reduced level of noise and vibration.

Quantum-Chemical Study of Reactions between Dimethyl Carbonate and Methylamine Proceeding through an Addition–Elimination Mechanism on Zinc Oxide Catalysts

Quantum-Chemical Study of Reactions between Dimethyl Carbonate and Methylamine Proceeding through an Addition–Elimination Mechanism on Zinc Oxide Catalysts

A Data-Driven Genetic Algorithm for Power Flow Optimization in the Power System With Phase Shifting Transformer

Phase-shifting transformer (PST) is one of the flexible AC transmission technologies to solve the problem of uneven power transmission. Considering that PST can also be used as a regulation means for the economic operation of the system, it is necessary to study the power flow optimization of power systems with PST. In order to find a more efficient power flow optimization method, an improved genetic algorithm including a data-driven module is proposed. This method uses the deep belief network (DBN) to train the sample set of the power flow and obtains a high-precision proxy model. Then, the calculation of the DBN model replaces the traditional adaptation function calculation link which is very time-consuming due to a great quantity of AC power flow solution work. In addition, the sectional power flow reversal elimination mechanism in the genetic algorithm is introduced and appropriately co-designed with DBN to avoid an unreasonable power flow distribution of the grid section with PST. Finally, by comparing with the traditional model-driven genetic algorithm and traditional mathematical programming method, the feasibility and the validity of the method proposed in this paper are verified on the IEEE 39-node system.

Identification and Characterization of in vitro Metabolites of Belinostat by Rat Liver Microsomes using Ultra Performance Liquid Chromatography Coupled with Tandem Mass Spectrometry

Abstract: Objectives: The objective of the present study is to study the in-vitro metabolites of FDA approved anticancer drug, belinostat which is a histone deacetylase inhibitor. Methods: The metabolites were formed by incubating the drug, belinostat with rat liver microsomes, at 37°C for 24 hr. The newly formed metabolites were identified and characterized with the help of ultra-high performance liquid chromatography which is interlinked with tandem quadrupole time-of-flight mass spectrometry. Results: Two Phase-I metabolites were formed which include a belinostat amide (reductive metabolite) and belinostat acid (deaminated belinostat). We then elucidated the structures of the formed metabolites based on LC-MS/MS data which included accurate masses, the fragmentation of ions and chromatographic retention times. Conclusion: This study describes the detailed in-vitro metabolite profiling of belinostat which will be further helpful to predict the in-vivo metabolism of belinostat in the human body. Enzyme kinetic parameters (Km and Vmax) for both the metabolites were also established using different substrate concentrations. The study will be helpful in determining the safety and efficacy of the drug. This will further help in determining the elimination mechanism of belinostat which in turn will assist in predicting the effectiveness and toxicity of the drug. Key words: Belinostat; Rat Liver Microsomes; Characterization; in-vitro Metabolites; Enzyme Kinetics; LC-MS/MS.

Simultaneous adsorption of As(III) and Pb(II) by the iron-sulfur codoped biochar composite: Competitive and synergistic effects

Simultaneous elimination of As(III) and Pb(II) from wastewater is still a great challenge. In this work, an iron-sulfur codoped biochar (Fe/S-BC) was successfully fabricated in a simplified way and was applied to the remediate the co-pollution of As(III) and Pb(II). The positive enthalpy indicated that the adsorption in As-Pb co-pollution was an endothermic reaction. The mechanism of As(III) removal could be illustrated by surface complexation, oxidation and precipitation. In addition to precipitation and complexation, the elimination mechanism of Pb(II) also contained ion exchange and electrostatic interactions. Competitive and synergistic effects existed simultaneously in the co-contamination system. The suppression of As(III) was ascribed to competitive complexation of the two metals on Fe/S-BC, while the synergy of Pb(II) was attributed to the formation of the PbFe2(AsO4)2(OH)2. Batch experiments revealed that Fe/S-BC had outstanding ability to remove As(III) and Pb(II), regardless of pH dependency and interference by various coexisting ions. The maximum adsorption capacities of the Fe/S-BC for As(III) and Pb(II) were 91.2 mg/g and 631.7 mg/g, respectively. Fe/S-BC could be treated as a novel candidate for the elimination of As(III)-Pb(II) combined pollution.

Industry 4.0 Engineering Product Life Cycle Management Based on Multigranularity Access Control Model.

In order to improve the management efficiency of the safety status of Industry 4.0 engineering products, the multigranularity access control model (MGACM) Industry 4.0 engineering product life cycle management (PLM) is adopted to optimize the safety management mode of Industry 4.0 engineering products in this paper. The multigranularity access control model is constructed in this paper, which has strong nonlinearity and better fault tolerance. In addition, the parameters of PLM are optimized through the multiparticle access control model, and PLM search is enabled. Taking into account the slow and easy convergence of the multigranular access control model, a niche technology with full life cycle heterogeneity and elimination mechanism is proposed to solve the premature convergence problem of the multigranular access control model. The final simulation results of this paper show that, compared with traditional algorithms, the proposed multigranularity access control model is more reliable and effective and has faster convergence speed and higher management efficiency.

Nucleophilic Substitution at Heteroatoms-Identity Substitution Reactions at Phosphorus and Sulfur Centers: Do They Proceed in a Concerted (SN2) or Stepwise (A-E) Way?

The mechanisms of three selected identity substitution reactions at phosphorus and sulfur occurring with stereospecific inversion have been investigated using density functional theory (DFT). The first identity reaction between methoxyl anion and methyl ethylphenylphosphinate 1 reported in 1963 has been shown to proceed in a stepwise fashion according to the addition–elimination (A–E) mechanism involving formation of a pentacoordinate phosphorus intermediate (TBI-1). In contrast, the results of DFT studies of the identity chloride exchange reaction in (ethoxy)ethylphosphonochloridothionate 3 in acetone solution provided evidence that it proceeds synchronously according to the classical Ingold’s SN2-P mechanism. DFT calculations of the methoxyl–methoxy exchange reaction at sulfur in methyl p-toluenesulfinate 4 catalyzed by trifluoroacetic acid in methanol revealed that it proceeds stepwise (A–E mechanism), involving the formation of the high-coordinate sulfurane intermediate. In both identity transesterification reactions, 1 and 4, the transiently formed trigonal bipyramidal intermediates with the two methoxyl groups occupying apical positions (TBI-1 and TBI-4) have higher free energy barriers for the Berry-type pseudorotation than those for direct decomposition to starting phosphinate and sulfinate ensuring stereospecific inversion of configuration at the phosphinyl and sulfinyl centers. Thus, the DFT method proved its usefulness in the distinction between both mechanisms that are often indistinguishable by kinetic measurements.

Complexities of Regioselective Ring-Opening vs Transcarbonylation-Driven Structural Metamorphosis during Organocatalytic Polymerizations of Five-Membered Cyclic Carbonate Glucose Monomers.

Rigorous investigations of the organobase-catalyzed ring-opening polymerizations (ROPs) of a series of five-membered cyclic carbonate monomers derived from glucose revealed that competing transcarbonylation reactions scrambled the regiochemistries of the polycarbonate backbones. Regioirregular poly(2,3-α-d-glucose carbonate) backbone connectivities were afforded by 1,5,7-triazabicyclo[4.4.0]dec-5-ene (TBD)-catalyzed ROPs of three monomers having different cyclic acetal protecting groups through the 4- and 6-positions. Small molecule studies conducted upon isolated unimers and dimers indicated a preference for Cx–O2 vs Cx–O3 bond cleavage from tetrahedral intermediates along the pathways of addition–elimination mechanisms when the reactions were performed at room temperature. Furthermore, treatment of isolated 3-unimer or 2-unimer, having the carbonate linkage in the 3- or 2-position as obtained from either Cx–O2 or Cx–O3 bond cleavage, respectively, gave the same 74:26 (3-unimer:2-unimer) ratio, confirming the occurrence of transcarbonylation reactions with a preference for 3-unimer vs. 2-unimer formation in the presence of organobase catalyst at room temperature. In contrast, unimer preparation at −78 °C favored Cx–O3 bond cleavage to afford a majority of 2-unimer, presumably due to a lack of transcarbonylation side reactions. Computational studies supported the experimental findings, enhancing fundamental understanding of the regiochemistry resulting from the ring-opening and subsequent transcarbonylation reactions during ROP of glucose carbonates. These findings are expected to guide the development of advanced carbohydrate-derived polymer materials by an initial monomer design via side chain acetal protecting groups, with the ability to evolve the properties further through later-stage structural metamorphosis.