Reaction Matrix Research Articles

Porous β-Mo2C nanoparticle clusters supported on walnut shell powders derived carbon matrix for hydrogen evolution reaction

Herein, we choose the waste walnut shell as the carbon source, and ammonium heptamolybdate as the molybdenum source to prepare the β-Mo2C catalyst supported on carbon matrix (Mo2C@C) by the calcination method for hydrogen evolution reaction (HER). The open pores in the porous Mo2C nanoparticle clusters can facilitate electrolyte permeation and hydrogen molecules release as well as the carbon matrix can enhance the conductivity. As a result, the optimal Mo2C exhibits an efficient HER performance, with an overpotential of 140 mV at 10 mA cm−2 and a Tafel slope of 63 mV dec−1 as well as excellent electrochemical stability. The strategy changing waste walnut shell into the effective catalysts sets an example for the searching and designing rational energy materials.

The Therapeutic Potential and Role of miRNA, lncRNA, and circRNA in Osteoarthritis.

Osteoarthritis (OA) is a disease characterized by progressive degeneration, joint hyperplasia, narrowing of joint spaces, and extracellular matrix metabolism. Recent studies have shown that the pathogenesis of OA may be related to non-coding RNA, and its pathological mechanism may be an effective way to reduce OA. The purpose of this review was to investigate the recent progress of miRNA, long noncoding RNA (lncRNA) and circular RNA (circRNA) in gene therapy of OA, discussing the effects of this RNA on gene expression, inflammatory reaction, apoptosis and extracellular matrix in OA. The following electronic databases were searched, including PubMed, EMBASE, Web of Science, and the Cochrane Library, for published studies involving the miRNA, lncRNA, and circRNA in OA. The outcomes included the gene expression, inflammatory reaction, apoptosis, and extracellular matrix. With the development of technology, miRNA, lncRNA, and circRNA have been found in many diseases. More importantly, recent studies have found that RNA interacts with RNA-binding proteins to regulate gene transcription and protein translation, and is involved in various pathological processes of OA, thus becoming a potential therapy for OA. In this paper, we briefly introduced the role of miRNA, lncRNA, and circRNA in the occurrence and development of OA and as a new target for gene therapy.

A robust, hand-powered, instrument-free sample preparation system for point-of-care pathogen detection

Here, we describe a simple, universal protocol for use in nucleic acid testing-based pathogen diagnostics, which requires only hand-powered sample preparation, including the processes of pathogen enrichment and nucleic acid isolation. The protocol uses low-cost amine-functionalized diatomaceous earth with a 1-μm Teflon filter as a reaction matrix in both stages of the process, using homobifunctional imidoesters. Using a simple syringe as a pump, the capture efficiency for a large sample volume (<50 mL) was enhanced by up to 98.3%, and the detection limit was 1 CFU/mL, 100-fold better than that of common commercial nucleic acid isolation kit. This protocol can also be combined with commercialized 96-well filter plates for robust sample preparation. Our proposed system is robust, simple, low-cost, universal, and rapid (taking <20 min), and it works regardless of the ambient environment and sample pretreatment, requiring no electricity or instruments. Its benefits include the simplicity of producing its components and its ease of operation, and it can be readily integrated with other assays for point-of-care diagnostics.

Investigation of the Wigner Reaction Matrix of Microwave Networks Simulating Quantum Graphs with Broken Time Reversal Symmetry-One-Port Investigation

Investigation of the Wigner Reaction Matrix of Microwave Networks Simulating Quantum Graphs with Broken Time Reversal Symmetry-One-Port Investigation

Application of matrix semi-tensor product in chaotic image encryption

This paper proposes a new image encryption method based on matrix semi-tensor product theory. Using Hyperchaotic Lorenz system to generate chaotic sequences, and then using this chaotic sequence to generate two fixed scrambling matrices. The plain image is scrambled by chaotic positioning sort scrambled method. Analogous to a chemical reaction, the plain image scrambled image is one of the reactant, then add a matrix which is related to the plain image information and extracted from the chaotic sequence (this matrix can be differ in size from the plain image matrix, different matrices can be intercepted and generated according to different plain image). This matrix is scrambled as another reactant, Apply the method of semi-tensor product to carry on the reaction (diffusion), finally get the product (encryption image). This method breaks the shackles of the traditional matrix operation and makes the reaction matrix have more forms. Compared with other experimental results, the proposed algorithm is more secure and available.

May a natural lake behave as an efficient Fenton reactor under dark conditions?

Phenol degradation experiments were performed to study the potential behavior of the acidic Lake Caviahue (LC) as a dark Fenton reactor under natural conditions and upon H2O2 addition at doses typically used for technological applications. In both cases, to assess the influence of dissolved organic matter present in the lake, control experiments were carried out under identical initial conditions (pH, concentrations of phenol, iron, and H2O2), but in the absence of organic matter. A first set of experiments was performed to test the feasibility of dark Fenton processes under environmental conditions. Lake water samples were used as reaction matrix and catalyst source, whereas phenol and H2O2 were added as model pollutant and oxidant, respectively. H2O2 concentrations used were similar to those reported for rainwater. Results show that phenol can be degraded under all conditions studied and that the amount of phenol consumed depends on both the H2O2 concentration added and the matrix composition LC A second set of experiments was designed to characterize the lake behavior as a natural Fenton reactor upon the addition of H2O2 concentrations typically used for technological applications. Although phenol concentration profiles obtained for LC and the artificial solution show the characteristic behavior of Fenton-like systems, the trends are rather different, since for LC, the lag phase is much longer than that for the artificial matrix. Overall, the results suggest that the Fe(III)-chelating effect of the organic matter present in LC slows down reaction rates, but it does not block phenol degradation through Fenton-like processes.

Oxidative Breakers Can Stimulate Halogenation and Competitive Oxidation in Guar-Gelled Hydraulic Fracturing Fluids.

A number of flowback samples derived from horizontally drilled hydraulic fracturing (HDHF) operations reveal consistent detections of halogenated organic species, yet the source of these compounds remains uncertain. Studies simulating subsurface conditions have found that oxidative "breakers" can halogenate certain additives, but these pathways are unverified in the presence of cross-linked-gels, common features of HDHF operations. Using a high-throughput custom reactor system, we implemented a reaction matrix to test the capacity for halogenation of two frequently disclosed compounds with demonstrated halogenation pathways (cinnamaldehyde and citric acid) across guar gels with varied types and concentrations of cross-linkers and oxidative breakers. Cinnamaldehyde halogenation proceeded most readily in borate cross-linked gels at high ammonium persulfate dosages. Citric acid formed trihalomethanes (THMs) broadly across the matrix, generating brominated THMs at higher levels of hypochlorite breaker. Isolated removals of cross-linker or guar enhanced or diminished certain product formations, highlighting additional capacities for relevant ingredients to influence halogenation. Finally, we analyzed flowback samples from the Denver-Julesberg Basin, finding that additions of oxidant enhanced halogenation. As a more realistic subsurface simulation, this work demonstrates strict criteria for the subsurface halogenation of cinnamaldehyde and the broad capacity for THM formation due to systematic oxidant usage as gel breakers in HDHF operations.

Investigation of the diagonal elements of the Wigner\u2019s reaction matrix for networks with violated time reversal invariance

The distributions of the diagonal elements of the Wigner’s reaction hat{K} matrix for open systems with violated time reversal T invariance in the case of large absorption are for the first time experimentally studied. The Wigner’s reaction matrix links the properties of chaotic systems with the scattering processes in the asymptotic region. Microwave networks consisting of microwave circulators were used in the experiment to simulate quantum graphs with violated T invariance. The distributions of the diagonal elements of the reaction hat{K} matrix were experimentally evaluated by measuring of the two-port scattering matrix hat{S}. The violation of T invariance in the networks with large absorption was demonstrated by calculating the enhancement factor W of the matrix hat{S}. Our experimental results are in very good agreement with the analytic ones attained for the Gaussian unitary ensemble in the random matrix theory. The obtained results suggest that the distributions P(ʋ) and P(u) of the imaginary and the real parts of the diagonal elements of the Wigner’s reaction hat{K} matrix together with the enhancement factor W can be used as a powerful tool for identification of systems with violated T symmetry and quantification of their absorption.

The use of artificial intelligence’s elements to block the manifestations of individuals’ behavioral activity going beyond the quasi-stable states

The monitoring of the metastable states of individuals as a bifurcation point of development of intellectual dynamics of behavioural activity allows us to identify a set of characteristics of coherent-resonant clusters of manifestations of biophysical factors and information-cognitive nature. Conscious changes in the functioning modes of brain and human nervous system can be achieved by electromagnetic influence or purely informational influence as well as by the combined effect of both these factors. The arrangement of complex processes of informational influence is required to penetrate to the level of conscious (semantic) and unconscious (mental, emotional, meditative) interpretation of events when it is necessary to ensure sufficiently stable cognitive-behavioural stereotypes of individuals and their groups. Convergent informational and electromagnetic effects facilitate the effect on the brain, including the use of neuro-linguistic programming for this element with correction or even a complete change of the reflexive matrix (matrix of key reflexive reactions) with a corresponding change and fixation of the personality-style in the personality events to block the release of behavioural activity of individuals beyond quasi-stable states.

Ultrafine iron-cobalt nanoparticles embedded in nitrogen-doped porous carbon matrix for oxygen reduction reaction and zinc-air batteries

Oxygen reduction reaction (ORR) is a key process in renewable energy conversion and storage technologies, including fuel cells and metal-air batteries. Pt is a highly efficient ORR electrocatalyst, but its large-scale application is severely prohibited by the high cost. In the pursuit of cost-effective electrocatalysts, it is urgent to develop non-noble metal ORR catalysts. Herein, we report a facile strategy for synthesizing an ORR electrocatalyst based on ultrafine bimetallic FeCo nanoparticles (NPs) anchoring on N-doped porous carbon matrix (FeCo-NC). By optimizing the ratio of Fe and Co, the FeCo-NC-1 catalyst exhibits excellent performance for ORR with the half-wave potential of 0.84 V and limiting current density of −5.3 mA cm−2, which is comparable to the commercial Pt/C catalyst. When applied to Zn-air batteries, FeCo-NC-1 catalyst possesses a high open-circuit potential (1.50 V) and large specific capacity (726.2 mA h g−1) with a good long-term stability and methanol-tolerant capability, which are even superior to the commercial Pt/C catalyst. The first-principle calculations indicate the bimetallic FeCo-NC has stronger O2 adsorption than the single metal nitrogen-doped carbon catalysts (Fe-NC and Co-NC), which is the primary reason for the better ORR performance. We believe this work can be helpful for the development of inexpensive and high-efficient ORR electrocatalysts.

Integrating energy transferability into the connection-detail of coastal bridges using reinforced interfacial epoxy-polyurea reaction matrix composite

A new Carbon-fiber Interfacial Epoxy-Polyurea Matrix (C-IEPM) composite is investigated as a potential retrofit option for vulnerable girder-to-cap connection-details in coastal highway bridges. IEPM is a reaction of cross-linking epoxy with functional groups of pre-polymerized polyurea, producing an energy-transfer mechanism inherently absent in conventional carbon-fiber reinforced epoxy (CF/E) that drastically reduces the serviceability limit state during extreme hurricane events. IEPM is a covalently bonded interface, produced as a reaction of migrating epoxy species (epoxide and amine-based hardener), controlled as a function of their curing time (tc), with highly reactive isocyanate and amine polyurea moieties. To demonstrate IEPM effectiveness, six scaled concrete girders were tested using a modified simulated storm surge and slamming wave force function, derived using regional maps for a 100-year return-period Hurricane Katrina. Two girders, designed using current AASHTO field connection-details, failed catastrophically (concrete shear failure) in less than one-half load cycle. The CF/E-strengthened girder, failing in less than one load cycle, experienced severe damage to its girder-to-cap connection, including fiber and epoxy matrix breakage, delamination, unsustainable girder-end rotations, and transient force-displacement hystereses loops. However, after 12 load cycles, the C-IEPM-strengthened girder, providing substantial energy transferability (material damping) through its connection-details, experienced only local cracking.

Performance of hybrid systems coupling advanced oxidation processes and ultrafiltration for oxytetracycline removal

In this study, the efficiency of three different hybrid systems coupling ultrafiltration (UF) with (i) UVC/H2O2, (ii) UVC/TiO2, and (iii) UVC was evaluated for the treatment of a secondary effluent (SE) from a municipal wastewater treatment plant and a surface water (SW) from Miedwie Lake, both spiked with 5 mg L−1 of oxytetracycline (OTC). A ceramic membrane made of TiO2 was tested. The effect of H2O2 concentration (30 to 120 mg L-1) on the UVC/H2O2-UF system and of P25-TiO2 loading (0.5 to 1.5 g L-1) in suspension on the photocatalytic UVC/TiO2-UF system were investigated. A photonic flux of 5.1 J s-1 was provided in all systems. The maximum pure water flux (PWF) was 111 L m-2 h-1. Adsorption on the photocatalyst particles and/or on the membrane surface was found to be an important contribution for the removal of OTC and dissolved organic carbon (DOC). The UF membrane contributed significantly to photocatalyst and pollutants rejection in the photocatalytic membrane reactor (PMR) with the UVC/TiO2 system; whereas when using the UVC/H2O2 process, with the highest H2O2 dose, the membrane effect was negligible. Using SE as reaction matrix in the UVC/TiO2-UF system with 1.0 g L-1 of TiO2, the complete OTC removal was achieved in 5 h with a mineralization of 49%. For the same reaction period, a DOC removal of 52% was achieved with the UVC/H2O2-UF system (120 mg H2O2 L-1). A similar permeate flux decrease (ca. 40%) was observed in both cases. Furthermore, the highest reduction of permeate flux (60%) was observed when using the UVC-UF system. Using SW as reaction matrix, higher OTC degradation rates and percentage of mineralization were reached for the same reaction period, when compared with SE, due to the lower COD and inorganic salts concentration present in the surface water.

Incorporating Brueckner-Hartree-Fock correlations in energy density functionals

Recently, a microscopically motivated nuclear energy density functional was derived by applying the density matrix expansion to the Hartree-Fock (HF) energy obtained from long-range chiral effective field theory two- and three-nucleon interactions. However, the HF approach cannot account for all many-body correlations. One class of correlations is included by Brueckner-Hartree-Fock (BHF) theory, which gives an improved definition of the one-body HF potential by replacing the interaction by a reaction matrix $G$. In this paper, we find that the difference between the $G$-matrix and the nucleon-nucleon potential $V_{\mathrm{NN}}$ can be well accounted for by a truncated series of contact terms. This is consistent with renormalization group decoupling generating a series of counterterms as short-distance physics is integrated out. The coefficients $C_{n}$ of the power series expansion $\sum C_{n}q^{n}$ for the counterterms are examined for two potentials at different renormalization group resolutions and at a range of densities. The success of this expansion for $G-V_{\mathrm{NN}}$ means we can apply the density matrix expansion at the HF level with low-momentum interactions and density-dependent zero-range interactions to model BHF correlations.

Controlled alloying of Pt-Rh nanoparticles by the polyol approach

We report on a facile synthesis strategy for the reaction matrix platinum(II)-acetylacetonate − rhodium(III)-acetylacetonate − polyvinylpyrrolidone − 1,4-butanediol and show that phase pure Pt-Rh alloyed nanoparticles can be achieved with compositional control based on simultaneous decomposition of Pt- and Rh-metal precursors. By combining data from powder X-ray diffraction, (high-resolution) transmission electron microscopy [(HR)TEM], energy dispersive X-ray spectroscopy (EDS) and kinetic experiments, we describe key parameters for compositional control. Powder X-ray diffraction suggests a crystallite size of around 4 nm, less than the size of polycrystalline particles, of around 7 nm in average and with different morphologies, as imaged by TEM. High-Angle Annular Dark Field Scanning TEM and EDS show some compositional fluctuations between and within in the received Pt-Rh nanoparticles. Based on insight to the reaction kinetics of the individual Pt and Rh metal precursors, recipes are fine-tuned to provide bimetallic nanoparticles with controlled average composition, including achieving the identical Pt/Rh molar ratio for the resulting nanoparticles as defined by the precursor mixture prior to the simultaneous reduction step. The adopted approach adds value beyond the Pt-Rh system and shows that control of precursor reactivity is essential to provide exact metal compositions of bimetallic nanoparticles for use in fundamental studies and applications.

Markov model of representation of sensual images for the formation of the model of the outside world

The aim of the studyis a probabilistic description of the functioning of the cognitive system, taking into account its internal logic and interaction with the external environment.Such concepts of cognitive theory as sensory imaginative representations, models, systems are the most common, so the attempt to formalize them is by obtaining the most common results. One of the key concepts of cognitive theory is Gestalt, which is understood in this work as a kind of holistic perception of the sensual image, as well as the sensual image. Formalization (mathematical description) of Gestalt, as well as other concepts of cognitive theory meets the natural difficulties associated with the uncertainty of these concepts. On the other hand, there are well-developed mathematical models of behavior of quite specific organizational systems, allowing obtaining meaningful results. In this regard, the mathematical description of a wide class of cognitive systems, not limited to the specific content of their functioning, is an urgent task. In this study, it is assumed that sensory images occur at random times and affect the cognitive system with certain probabilities. In this regard, one of the adequate mathematical tools are, apparently, probability-theoretic methods, in particular, the application of the theory of Markov processes. The methodof research within the framework of the adopted model is the application of the theory of Markov processes developing at fixed points in time, i.e. Markov chains. It is believed that the functioning of the cognitive system is described by abstract probabilities of changes in the system states. This approach allows formalizing the processes of representation of sensory images in the cognitive system, taking into account both the internal logic of the system and the interaction of the system with the outside world. The main attention is paid to the study of the influence on the behavior of the system external to her sensual images.As a resultof the study shows that the inclusion of the interactions of the system is achieved by introducing the stochastic matrix of probabilities of the system response to external influences. Taking into account the well-developed theory of Markov chains, analytical expressions for the probabilities of the system in each of the possible states are obtained. The influence on the behavior of the system of elements of the matrix of probability reactions of the system is investigated, the corresponding graphs are presented. The asymptotic behavior of the system is studied with an unlimited increase in the number of steps that change the state of the system, as well as the average characteristics of the system. It is noted that the presented description is formal, operates only with probabilistic characteristics of the system and does not take into account specific signals that can enter the system from its sensors, and generally sensitive elements. In this regard, the further development of the model may be associated with the assessment of the probability of the system response to external influences, taking into account the characteristics of these specific signals, as well as the development of optimal algorithms for decision-making about the presence or absence of impacts on the system from the outside world.

Low-energy collisions between electrons and hydrogen fluoride cations

We have studied slow electron collisions with hydrogen fluoride cations in the framework of multi-channel quantum defect theory. Assuming energy-independent interactions, the short-range reaction matrix has been evaluated in the second order of the Born expansion of the Lippmann–Schwinger equation. The isotopic effects on the cross sections and thermal rate coefficients for dissociative recombination, vibrational excitation and de-excitation have been investigated.

Mechanistic Insights into Interactions between Bacterial Class I P450 Enzymes and Redox Partners

Cytochrome P450 enzymes are highly diversified biocatalysts associated with steroid biosynthesis, xenobiotic metabolism, biosynthesis of natural products, and industrial oxidation reactions. A typical P450 catalytic cycle requires sequential transfer of two electrons from NAD(P)H to the heme-iron reactive center for O2 activation. For the most abundant bacterial Class I P450 systems, this important process is usually mediated by two redox partner proteins including an FAD-containing ferredoxin reductase (FdR) and a small iron–sulfur protein, ferredoxin (Fdx). However, it is often unclear which pair of Fdx and FdR among multiple redox partners is the optimal one for a specific Class I P450 enzyme. To address this important but underexplored question, herein, a reaction matrix network with 16 Fdxs, 8 FdRs, and 6 P450s (against 7 substrates) was constituted. By analyzing the reactivity profiles of 896 P450 reactions, together with phylogenetic analysis, redox potential measurements, structural simulations, a...

Development of the Reaction/Distillation matrix to include more complicated Reaction/Distillation systems and performance evaluation using an ethylene hydration case study

Reaction/Separation systems are very important in chemical industries and synthesis of all possible configurations for these systems is necessary for finding the best process alternative. An algorithm for synthesis of different alternatives for reaction–distillation systems is presented in this paper. The presented algorithm is a developed version of the Separation Matrix which has been introduced for generation of different distillation sequences. An initial version of the Reaction/Distillation matrix for a two-component reaction prevailing within a four-component system has already been introduced by the authors. The current research is the expansion of the previous work to include multiple reactions in a system containing any number of reactive and non-reactive components. This algorithm can also generate the sequences including components forming binary azeotropes. For performance evaluation purposes, a case study including two reactions is presented in which a binary azeotrope is formed between two components. The possible sequences for the system are generated using the introduced algorithm and the obtained sequences are simulated and compared in terms of total annual cost.

Synthesis of passive fractional‐order LCn‐port with three element orders

Fractional-order circuits find a widespread use in different engineering applications. The problem of realising fractional-order circuits has been discussed by several authors, however, it is far from being solved. Realising fractional-order resistorless passive network with three element orders is been studied. At first, this study extends the two-variable reactance matrix synthesis method to three-variable case, and then proposes a synthesis method of fractional-order reactance matrix with three element orders by variable substitution. The process in above methods mainly involves variable substitution, decomposition of three-variable reactance matrix, extraction of unit inductors, Laurent series expansion, spectral factorisation of two-variable positive semidefinite Hermitian matrix and synthesis of univariable reactance matrix. Then the above-mentioned synthesis process is illustrated by two examples.

Insights Into the Sunlight-Driven Water Oxidation by Ce and Er-Doped ZrO 2.

In the present work, the activity of Ce and Er-doped ZrO2 nanopowders for sun-driven photocatalytic water oxidation has been investigated. ZrO2 powders with tunable amounts of tetragonal, monoclinic and cubic polymorphs have been synthesized by introducing Ce and Er (from 0.5 to 10 mol % on an oxide basis) through hydrothermal method. The aim of this work is to investigate the role of rare earth (RE) ions rich of electrons (Er3+) and with entirely empty levels (Ce4+) in the ZrO2 matrix for the sun-driven photocatalytic water oxidation reaction. The samples have been characterized by means of UV-Vis spectroscopy, X-Ray diffraction (XRD), N2 adsorption, X-ray photoelectron spectrophotometry (XPS) and transmission electronic microscopy (TEM) with energy dispersive spectroscopy (EDS). With respect to the bare ZrO2 mainly containing monoclinic (m-) phase, an increasing amount of rare-earth (RE) dopant was found to improve the specific BET surface area and to stabilize the tetragonal (t-) or cubic (c-) polymorphs of ZrO2 at room temperature. XRD data confirmed that dopants were mainly inserted in the t-ZrO2 phase. The photocatalytic O2 evolution from water under AM 1.5 G simulated sunlight illumination of the prepared samples have been correlated with their optical, structural and chemical properties. The effect of the dopant concentration on the chemical-physical and photocatalytic properties of the Er- and Ce-doped ZrO2 materials was elucidated. The samples with 5% of RE oxide were the most active, i.e., three times more than pure zirconia. Their superior photocatalytic activity was found to be mainly correlated to two factors: (i) an optimal surface concentration of RE ions of about 3.7%, which increased charge carriers separation in the photocatalysts surface due more superficial defects of the t-ZrO2 and a higher surface area, thus enhancing the reaction kinetics, (ii) a controlled amount of monoclinic vs. tetragonal (or cubic) polymorphs of zirconia with an optimum ratio of about 70/30 of t-ZrO2/m-ZrO2. Instead, the increased ability of the RE-doped ZrO2 to harvest visible light was found to have a secondary role on the photocatalytic activity of the Ce-doped ZrO2 material.