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We propose a simple, efficient, and reliable procedure for implicit time stepping, regarding a special case of the viscoplasticity model proposed by Simo and Miehe (1992). The kinematics of this popular model is based on the multiplicative decomposition of the deformation gradient tensor, allowing for a combination of Newtonian viscosity and arbitrary isotropic hyperelasticity. The algorithm is based on approximation of precomputed solutions. Both Lagrangian and Eulerian versions of the algorithm with equivalent properties are available. The proposed numerical scheme is non‐iterative, unconditionally stable, and first order accurate. Moreover, the integration algorithm strictly preserves the inelastic incompressibility constraint, symmetry, positive definiteness, and w‐invariance. The accuracy of stress calculations is verified in a series of numerical tests, including non‐proportional loading and large strain increments. In terms of stress calculation accuracy, the proposed algorithm is equivalent to the implicit Euler method with strict inelastic incompressibility. The algorithm is implemented into MSC.MARC and a demonstration initial‐boundary value problem is solved. [ABSTRACT FROM AUTHOR]

The article discusses the polymerization scheme of benzoxazine monomer based on 4,4′‐diaminodiphenylmethane (P‐ddm) and the chemical structure of polybenzoxazine based on it poly(P‐ddm). The polymerization behavior of benzoxazine P‐ddm is studied using differential scanning calorimetry (DSC). Solid‐state 13C MAS NMR is used to determine the chemical structure of poly(P‐ddm). It is revealed that the сhemical structure of poly(P‐ddm) predominantly consists not of phenolic Mannich bridges, as expected, but of methylene bridges, which indicates the process of deamination of phenolic Mannich bridges. However, no weight loss associated with the expected release of free amine during this process is detected. This may indicate the incorporation of a diamine moiety into the polymer chain through the formation of imine bonds, the signal of which is detected in the 13C MAS NMR and FTIR spectra of the poly(P‐ddm), and on the 1H and 13C NMR spectra of model polybenzoxazine based on p‐cresol and 4,4′‐diaminodiphenylmethane poly(pC‐ddm). Based on the data obtained, a hypothesis is put forward about the formation of a network polymer, the structure of which consists mainly of methylene and imine units. [ABSTRACT FROM AUTHOR]

This paper provides new experimental data regarding inelastic strain accumulation in structural steel samples. The samples are subjected to stress‐controlled cyclic loading with positive mean stress within each cycle; the loading blocks are combined in a complex pattern to study the effect of load history. A large‐strain ratcheting model is constructed based on a material law with a nonlinear kinematic and isotropic hardening. A new rule of ductile damage accumulation is suggested and a class of models with hardening stagnation is introduced. We show that models which include the hardening stagnation describe the experimental data more accurately. Unfortunately, due to a large spread of mechanical properties from sample to sample, it is impossible to describe the entire set of experiments using a single set of parameters. To address this challenge, we have developed novel mathematical tools for parameter identification in the context of stochastic variations in mechanical properties. These tools include the concept of a collar of model responses and the notion of protrusion. We propose an extended parameter identification problem that rethinks the standard error functional. We demonstrate that the extended identification problem effectively accounts for the large spread observed in experimental data when applied to the developed ratcheting model. [ABSTRACT FROM AUTHOR]

We studied a reaction of chromone‐containing acrylonitriles and cyanoacrylates with acid hydrazides. This reaction turned out to be a method for the synthesis of salicyloyl‐substituted 1,2,4‐triazolo[1,5‐a]pyridines. The synthesis developed is a tandem ring‐opening/double ring‐closing process. This synthetic approach is characterized by low toxic solvents (ethanol, butanol) and mediator (Et3N), 37–84% yields, non‐chromatographic isolation of products, and substrate tolerance (59 examples). [ABSTRACT FROM AUTHOR]

We report the development of a convenient organocatalytic method for the synthesis of 5H‐pyrano[3,2‐c]chromenes from chromone‐containing acrylates and ethyl cyanoacetate. The synthesis is characterized by simple conditions (ethanol, basic catalysis) and good yields (up to 90 %). The synthesized pyrano[3,2‐c]chromenes are a promising new class of fluorescent compounds. They have intense fluorescence in the yellow‐green region of the spectrum (495–554 nm) with high quantum yields (up to 72 %) and exhibit large Stokes shifts (3514–5856 cm−1). We have demonstrated the possible application of the obtained pyrano[3,2‐c]chromenes as selective "turn‐off" sensors for nucleophilic anions, such as cyanide, sulfide and sulfite. [ABSTRACT FROM AUTHOR]

BACKGROUND: Downstream processing is an important part of industrial steroid biotechnology. The traditional recovery methods require significant amounts of the organic solvents which are associated with environmental risks. There is a need for environmentally friendly downstream processing which also may open the prospects for regeneration and repeated use of the costly materials. RESULTS: Microbial conversion of phytosterol to C17‐ketosteroids in methylated cyclodextrin (mCD) solutions was studied as a model bioprocess. Quantitative aspects of competitive complexation of mCD and natural β‐CD (β‐CD) with steroids were studied under different temperature modes and CD concentrations. The method of steroid recovery based on precipitation of insoluble β‐CD complexes ensured the complete isolation of androst‐4‐ene‐3,17‐dione, androsta‐1,4‐diene‐3,17‐dione, 9α‐hydroxyandrost‐4‐ene‐3,17‐dione, 20‐hydroxymethyl‐pregna‐1,4‐dien‐3‐one and 3β‐hydroxyandrost‐5‐en‐17‐one from aqueous media. Analysis of the 1H nuclear magnetic resonance (NMR) spectra showed a constant molar ratio of β‐CD to steroid equal to 2 in the obtained steroid β‐CD complexes. The extraction of the steroid from the β‐CD complex by small volumes of organic solvent provided a quantitative yield. The method developed ensures regeneration and repeated use of the mCDs without decrease of the basic bioconversion outputs, as was demonstrated in a series of phytosterol to androsta‐1,4‐diene‐3,17‐dione bioconversions by Mycolicibacterium neoaurum VKM Ac‐1816D. CONCLUSIONS: Downstream processing based on manipulation of steroid solubility in aqueous cyclodextrin solutions is a promising alternative to traditional steroid extraction with organic solvents. This environmentally friendly approach ensures re‐use of materials without decrease in bioconversion outputs. © 2023 Society of Chemical Industry (SCI). [ABSTRACT FROM AUTHOR]

Simulations utilizing local constitutive equations for strain‐softening materials are known to be pathologically mesh‐dependent. The rational solution to this problem is to use nonlocal material models. In this paper, we discuss the application of the integral‐based approach to the simulation of non‐local damage accumulation and fracture. Various combinations of non‐localities with common spatial symmetries are analysed analytically and numerically. The symmetries include the plane strain and the axisymmetric cases, as well as the presence of symmetry planes and cyclic symmetries. Although not a symmetry, the practically important case of thin plates is also analysed. We show that the delocalization procedure should be executed using symmetry‐adapted averaging kernels. For the considered spatial symmetries, analytical closed‐form expressions are obtained. Moreover, a new easy‐to‐use averaging kernel is suggested, the same for 3D, plane strain and plane stress applications. To showcase the delocalization procedures, we consider a ductile damage model, based on the multiplicative decomposition of the deformation gradient, as well as hyperelastic relations between stresses and strains. FEM solutions for a series of problems are presented, including graduate damage accumulation, crack initiation and fracture. [ABSTRACT FROM AUTHOR]

Growth forms of tilings are an interesting invariant of tilings. They are fully understood in the periodic case but there are very few examples in the quasiperiodic case. Here this problem is studied for quasiperiodic tilings obtained by the grid method. It is proven that such tilings have polygonal/polyhedral growth forms that can be obtained as projections of central sections of orthoplexes. Furthermore, properties of the obtained growth forms in 2D and 3D cases are studied. This work contributes to a wider understanding of growth forms which can be used to study coordination numbers of grid tilings and in the calculation of topological densities. [ABSTRACT FROM AUTHOR]

BACKGROUND Laccase mediator systems (LMS) possess great potential in organic synthesis for selective oxidation in mild conditions. However, their usage in steroid synthetic chemistry is limited by low aqueous solubility of the substrates. In this study, the effect of steroid complexation with methylated cyclodextrin (mCD) on LMS oxidation has been studied. RESULTS: LMS consisted of Trametes versicolor laccase and 1‐hydroxybenzotriazole or TEMPO as redox mediators were used. The only product, ‐ 3β‐hydroxyandrost‐5‐en‐7,17‐dione (7‐keto‐DHEA) was detected during LMS oxidation of 3β‐hydroxyandrost‐5‐en‐17‐one (DHEA) at substrate concentrations within solubility. The formation of mCD complex with DHEA led to a decrease in the concentration of the reaction form of the substrate and inhibited bioconversion. When DHEA concentrations over its aqueous solubility was used, 3β,7α‐ and 3β,7β‐dihydroxyandrost‐5‐en‐17‐one (7α‐ and 7β‐OH‐DHEA) along with 7‐keto‐DHEA were formed. Both isomeric 7α‐ and 7β‐OH‐DHEA were efficiently converted to 7‐keto‐DHEA by LMS in the presence of mCD. LMS‐catalyzed oxidation of 20‐hydroxymethylpregn‐4‐en‐3‐one (HMP) in the presence of mCD resulted in a single product, pregn‐4‐en‐3‐one‐20‐carbaldehyde (20‐POA) and the reaction rate increased under elevated mCD concentrations. A preparative biochemical synthesis of 20‐POA was carried out, which has not been so far reported. CONCLUSIONS: mCD affects LMS‐catalyzed oxidation of steroid alcohols. The mechanism includes formation of steroid‐mCD inclusion complexes that could inhibit, or facilitate oxidation depending on the structure of steroid‐CD complex and accessibility of the hydroxyl functions to the LMS action. © 2021 Society of Chemical Industry (SCI). [ABSTRACT FROM AUTHOR]

Polypropylene (PP) random copolymers are an important class of commercial materials that can be tuned for a wide range of different applications. The structure–property relations are mainly discussed in this article focusing on two major influencing factors, the catalyst system and the type and amount of comonomer. Ziegler–Natta (ZN) catalyst systems still dominate the production of polypropylene and todays sixth‐generation ZN catalysts are based on postphthalate donor systems. Metallocene (MC) catalysts offer possibilities to exactly control the microstructure of the polymer even better. Mostly, ethylene is used as comonomer being randomly distributed for up to 7.3 mol% when using ZN catalysts. For single site catalysts, homogenous (single phase) materials can be achieved up to ethylene contents of 20.8 mol%. The incorporated comonomer reduces the crystallization speed and the lamellar thickness of the polymer thus affording soft and highly transparent materials. Random copolymers and terpolymers with higher α‐olefins only play a minor role but offer an additional possibility for property adjustments. PP random copolymers can also be varied in their performance through multistage polymerizations, altering the comonomer content and or the molecular weight in the different polymerization reactors. [ABSTRACT FROM AUTHOR]

We report a flexible approach to the synthesis of phenanthrene‐like heterocycles through organocatalytic ANRORC (Addition of the Nucleophile, Ring Opening, and Ring Closure) reaction of electron‐deficient 3‐vinylchromones with cyanoacetamide. Addition of highly basic DBU (1,8‐diazabicyclo[5.4.0]undec‐7‐ene) or tetramethylguanidine (TMG) at 80 °C leads to chromeno[4,3‐b]pyridines in good yields, whereas Et3N at 20 °C made it possible to obtain the less accessible pyrano[3,2‐c]chromenes and their 2‐imines. The synthesis proceeds in mild conditions (EtOH, 20–80 °C), is versatile and applicable for a wide scope of reactants. The obtained compounds show bright fluorescence in the range 460–595 nm with high quantum yields (up to 0.84) in various solvents (MeCN, DMSO, EtOH, H2O). [ABSTRACT FROM AUTHOR]

Peptide toxins of arthropods are one of the potential sources of bioactive substances. Toxins are able to bind to calcium channels and block them. Ca2+ ions play an important role in many cell processes, in particular, in apoptosis. In this work, we study the effect of some arthropod toxins on intracellular processes associated with the induction of apoptosis. Synthetic analogs of U5‐scytotoxin‐Sth1a, ω‐hexatoxin‐Hv1a, ω‐theraphotoxin‐Hhn2a, and μ‐agatoxin‐Aa1a toxins—inhibitors of calcium L, P, and Q channels and sodium channels were used in the study. Apoptosis was induced by AC‐1001 H3 peptide. We study the effect of toxins on the level of apoptosis, ROS, mitochondrial potential, GSH, and ATP in CHO‐K1 cells. We show that all the tested toxins are able to dose dependently block the induction of apoptosis triggered by AC‐1001 H3 and reduce the level of natural apoptosis in CHO‐K1 cells. Cell incubation with apoptosis inducer AC‐1001 H3 in the presence and absence of toxins causes an increase in the intracellular concentrations of ROS, ATP, and mitochondrial potential and decreases the GSH concentration. The present study reveals the antiapoptotic effect of a number of arthropod peptide toxins. The toxins studied can represent a novel approach used in the treatment of pathologies associated with the activation of apoptotic mechanisms. [ABSTRACT FROM AUTHOR]

Catalyst development for advanced isotactic polypropylene copolymer grades cannot be considered without parallel work on the polymerization process, especially when multi‐phase high‐impact ethylene‐propylene copolymers (also called heterophasic copolymers, HECOs) of complex composition are considered. Using a Ziegler–Natta type catalyst produced in an emulsion process and using citraconate ester as internal donor, a series of such high‐impact copolymers is first produced in a bench‐scale reactor. At this stage, the content of ethylene‐propylene copolymer (EPC) phase is varied in a wide range for understanding the catalyst performance as well as the resulting structure‐property relations, using three‐stage polymerization to emulate multiple reactors. Selected compositions are subsequently scaled up to a multi‐reactor pilot plant, demonstrating composition effects on mechanical performance. Both stages are accompanied by structural investigations using 13C‐NMR spectroscopy and atomic force microscopy. The novel catalyst is found to be capable of synthesizing HECOs in a wide range of elastomer (EPC) content, achieving free‐flowing polymer powders up to an elastomer content as expressed by the xylene cold soluble fraction of 37 wt%. [ABSTRACT FROM AUTHOR]

A new phenomenological model of cyclic creep, which is suitable for applications involving finite creep deformations of the material, is proposed. The model accounts for the effect of the transient increase of the creep strain rate upon the load reversal. In order to extend the applicability range of the model, the creep process is fully coupled to the classical Kachanov-Rabotnov damage evolution. As a result, the proposed model describes all the three stages of creep. Large strain kinematics is described in a geometrically exact manner using the assumption of a nested multiplicative split, originally proposed by Lion for finite strain plasticity. The model is thermodynamically admissible, objective, and w-invariant. The implicit time integration of the proposed evolution equations is discussed. The corresponding numerical algorithm is implemented into the commercial FEM code MSC.Marc. The model is validated using this code; the validation is based on real experimental data on cyclic torsion of a thick-walled tubular specimen made of the D16T aluminium alloy. The numerically computed stress distribution exhibits a 'skeletal point' within the specimen, which simplifies the analysis of test data. [ABSTRACT FROM AUTHOR]

The vertex graph of the Ammann–Beenker tiling is a well‐known quasiperiodic graph with an eightfold rotational symmetry. The coordination sequence and coordination shells of this graph are studied. It is proved that there exists a limit growth form for the vertex graph of the Ammann–Beenker tiling. This growth form is an explicitly calculated regular octagon. Moreover, an asymptotic formula for the coordination numbers of the vertex graph of the Ammann–Beenker tiling is also proved. [ABSTRACT FROM AUTHOR]

The first example of an unusual addition of chromone‐substituted acrylic acid to enamines is described. The process shows high versatility concerning both enamines and chromones. The reaction is catalyzed by tertiary amines and is highly likely of Morita–Baylis–Hillman‐type. The described compounds show combined moderate inhibitory action on BChE and antagonism towards NMDA receptors which makes them a perspective group for the development of anti‐Alzheimer drugs. An unusual addition of enamines to chromone‐substituted acrylic acid is an efficient and versatile method of synthesis of allylamine derivatives. The reaction is catalyzed by amines and is highly likely of Morita–Baylis–Hillman‐type. The described compounds show combined moderate inhibitory action on BChE and antagonism towards NMDA receptors [ABSTRACT FROM AUTHOR]

Properties of matrices manufactured by electrospinning from solutions of polyurethane Tecoflex EG-80A with gelatin in 1,1,1,3,3,3-hexafluoroisopropanol were studied. The concentration of gelatin added to the electrospinning solution was shown to influence the mechanical properties of matrices: the dependence of matrix tensile strength on protein concentration is described by a bell-shaped curve and an increase in gelatin concentration added to the elasticity of the samples. SEM, FTIR spectroscopy, and mechanical testing demonstrate that incubation of matrices in phosphate buffer changes the structure of the fibers and alters the polyurethane-gelatin interactions, increasing matrix durability. The ability of the matrices to maintain adhesion and proliferation of human endothelial cells was studied. The results suggest that matrices made of 3% polyurethane solution with 15% gelatin (wt/wt) and treated with glutaraldehyde are the optimal variant for cultivation of endothelial cells. [ABSTRACT FROM AUTHOR]

Summary: A popular version of the finite‐strain Maxwell fluid is considered, which is based on the multiplicative decomposition of the deformation gradient tensor. The model combines Newtonian viscosity with hyperelasticity of the Mooney‐Rivlin type; it is a special case of the viscoplasticity model proposed by Simo and Miehe in 1992. A simple, efficient, and robust implicit time‐stepping procedure is suggested. Lagrangian and Eulerian versions of the algorithm are available, with equivalent properties. The numerical scheme is iteration free, unconditionally stable, and first order accurate. It exactly preserves the inelastic incompressibility, symmetry, and positive definiteness of the internal variables and w‐invariance. The accuracy of the stress computations is tested using a series of numerical simulations involving a nonproportional loading and large strain increments. In terms of accuracy, the proposed algorithm is equivalent to the modified Euler backward method with exact inelastic incompressibility; the proposed method is also equivalent to the classical integration method based on exponential mapping. Since the new method is iteration free, it is more robust and computationally efficient. The algorithm is implemented into MSC.MARC, and a series of initial boundary value problems is solved to demonstrate the usability of the numerical procedures. [ABSTRACT FROM AUTHOR]

A new approach to study coordination shells and coordination sequences of quasiperiodic graphs is suggested. The structure of the coordination shells in the vertex graph of a Penrose tiling is described. An asymptotic formula for its coordination numbers is obtained. An essentially different behaviour of the coordination numbers for even and odd shells is revealed. [ABSTRACT FROM AUTHOR]

Planetary physics research is an important part of the high energy density ( HED) physics programme at the Facility for Antiprotons and Ion Research ( FAIR) at Darmstadt. In this paper, we report numerical simulations of a proposed experiment named LAboratory PLAnetary Sciences ( LAPLAS). These simulations show that in such experiments, an Fe sample can be imploded to extreme physical conditions that are expected to exist in the interior of the Earth and in the interior of more massive rocky planets named, super-Earths. The LAPLAS experiments will thus provide very valuable information on the equation-of-state ( EOS) and transport properties of HED Fe, which will help the scientists to understand the structure and evolution of the planets in our solar system and of the extrasolar system planets. [ABSTRACT FROM AUTHOR]

This paper presents numerical simulations of the thermodynamic and hydrodynamic response of a solid copper cylindrical target that is subjected to the full impact of one future circular collider (FCC) ultra-relativistic proton beam. The target is facially irradiated so that the beam axis coincides with the cylinder axis. The simulations have been carried out employing an energy deposition code, FLUKA, and a 2D hydrodynamic code, BIG2, iteratively. The simulations show that, although the static range of a single FCC proton and its shower in solid copper is ∼1.5 m, the full beam may penetrate up to 350 m into the target as a result of hydrodynamic tunnelling. Moreover, simulations also show that a major part of the target is converted into high energy density ( HED) matter, including warm dense matter ( WDM) and strongly coupled plasma. [ABSTRACT FROM AUTHOR]

The [4+2] cycloaddition of chromone-fused dienes with enamines was found to be an efficient method for the synthesis of 4,4a- and 3,4-dihydroxanthone derivatives. Either product type could be obtained by choosing the proper conditions [reaction time and addition of La(NO3)3 as a Lewis acid]. Calculations using density functional theory and Møller-Plesset perturbation theory showed that the isomerization of 4,4a-dihydroxanthones to 3,4-dihydroxanthones occurred through a base-assisted sigmatropic rearrangement. The described reaction provides a convenient route to a natural-product-inspired group of 4,4a-dihydroxanthones with cytotoxic activity. [ABSTRACT FROM AUTHOR]

Early Experiments at FAIR in 2018 - 2022 suggested by the HEDgeHOB collaboration in the field of non-ideal plasma physics are discussed. Specific energies of 5-10 kJ/g, pressures of 1-2 GPa and temperatures of 1-2 eV are expected to be reached in the substance at the first experiments with a U+28 beam with the energy of 0.2 AGeV and maximal intensity 3 · 1010 per impulse. It will provide the possibility to investigate the two phase region including the critical point of several metals in HIHEX (Heavy Ion Heating and EXpansion) experiments with the plane and cylindrical geometry, realizing regimes of quasi-isochoric heating, isentropic expansion and compression when the flow strikes the target. Analysis of thermal radiation transfer will give information on the vaporization dynamics. Measurements of electrical conductivity and optical properties on the supercritical adiabat will disclose information on the insulator to metal transition under these conditions. (© 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [ABSTRACT FROM AUTHOR]

A new and efficient route for the synthesis of derivatives of the poorly investigated pyrano[2,3- d][1,3]thiazine heterocyclic system is disclosed. These compounds were prepared via of 2-aryl-4-hydroxy-6 H-1,3-thiazine-6-ones with aliphatic and aromatic aldehydes in the presence of pyridine. The method is general and versatile, and the interaction is independent on the nature of the aldehyde, the only exceptions being formaldehyde and salicylaldehydes. [ABSTRACT FROM AUTHOR]

Key points The first sensory synapse formed between the central processes of primary afferents and dorsal horn neurons plays an important role in controlling the flow of nociceptive information from the periphery to the CNS, and plasticity at this synapse contributes to centrally mediated pain hypersensitivity., Although exocytosis and synaptic plasticity are regulated by presynaptic Ca2+, the mechanisms underlying presynaptic Ca2+ signalling at the first sensory synapse are not well understood., In this study we show that the plasma membrane Ca2+-ATPase and mitochondria are the major regulators of presynaptic Ca2+ signalling in capsaicin-sensitive dorsal root ganglion neurons accounting for ∼47 and ∼40% of presynaptic Ca2+ clearance, respectively., Quantitative analysis of changes in cytosolic and mitochondrial Ca2+ concentrations demonstrates that the mitochondrial Ca2+ uniporter is highly sensitive to cytosolic Ca2+ at this synapse., These results help us understand presynaptic mechanisms at the first sensory synapse., Abstract The central processes of primary nociceptors form synaptic connections with the second-order nociceptive neurons located in the dorsal horn of the spinal cord. These synapses gate the flow of nociceptive information from the periphery to the CNS, and plasticity at these synapses contributes to centrally mediated hyperalgesia and allodynia. Although exocytosis and synaptic plasticity are controlled by Ca2+ at the release sites, the mechanisms underlying presynaptic Ca2+ signalling at the nociceptive synapses are not well characterized. We examined the presynaptic mechanisms regulating Ca2+ clearance following electrical stimulation in capsaicin-sensitive nociceptors using a dorsal root ganglion (DRG)/spinal cord neuron co-culture system. Cytosolic Ca2+ concentration ([Ca2+]i) recovery following electrical stimulation was well approximated by a monoexponential function with a τ∼2 s. Inhibition of sarco-endoplasmic reticulum Ca2+-ATPase did not affect presynaptic [Ca2+]i recovery, and blocking plasmalemmal Na+/Ca2+ exchange produced only a small reduction in the rate of [Ca2+]i recovery (∼12%) that was independent of intracellular K+. However, [Ca2+]i recovery in presynaptic boutons strongly depended on the plasma membrane Ca2+-ATPase (PMCA) and mitochondria that accounted for ∼47 and 40%, respectively, of presynaptic Ca2+ clearance. Measurements using a mitochondria-targeted Ca2+ indicator, mtPericam, demonstrated that presynaptic mitochondria accumulated Ca2+ in response to electrical stimulation. Quantitative analysis revealed that the mitochondrial Ca2+ uptake is highly sensitive to presynaptic [Ca2+]i elevations, and occurs at [Ca2+]i levels as low as ∼200-300 n m. Using RT-PCR, we detected expression of several putative mitochondrial Ca2+ transporters in DRG, such as MCU, Letm1 and NCLX. Collectively, this work identifies PMCA and mitochondria as the major regulators of presynaptic Ca2+ signalling at the first sensory synapse, and underlines the high sensitivity of the mitochondrial Ca2+ uniporter in neurons to cytosolic Ca2+. [ABSTRACT FROM AUTHOR]

High Energy Density (HED) physics spans over numerous areas of basic and applied physics, for example, astrophysics, planetary physics, geophysics, inertial fusion and many others. Due to this reason, it has been a subject of very active research over the past many decades. Static as well as dynamic methods have been applied to generate samples of HED matter in the laboratory. The most commonly used tool in the static techniques is the diamond anvil cell while the dynamic methods involve shock compression of matter. During the past fifteen years, great progress has been made on the development of bunched intense particle beams that have emerged as an additional new tool for studying HED physics. In this paper we present two experiment designs that have been worked out for HED physics studies at the Facility for Antiprotons and Ion Research (FAIR) at Darmstadt. This facility has entered into construction phase and will provide one of the largest and most powerful particle accelerators in the world. (© 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [ABSTRACT FROM AUTHOR]

The need to change the reference configuration can naturally appear during the numerical simulation of multi-stage metal forming processes. In the current work, a refined approach to the consideration of previously induced plastic anisotropy is discussed, which is based on such configuration change. The model of finite strain viscoplasticity proposed by Shutov and Kreißig is considered in this study as a practical tool, suitable to capture the evolution of mechanical properties of material during inelastic deformation. The initial plastic anisotropy can be considered within this model by a special choice of initial conditions imposed on the relevant internal variables. A simple transformation law which is based on the isochoric change of the reference configuration is obtained in the current study. This transformation allows to obtain relevant initial conditions with respect to a new reference configuration. Thus, the initial conditions are formulated using the simulation results from the foregoing loading. The advocated approach is exemplified by the numerical simulation of equal channel angular pressing of cylindrical billets. The plastic anisotropy accumulated during a single ECAP pass is estimated using a series of virtual tension tests. These tests were performed on samples cut from processed billet with their gage lengths in different directions. Finally, the impact of the plastic anisotropy on the rotation of the workpiece within the output channel during ECAP is numerically estimated. [ABSTRACT FROM AUTHOR]

In this paper we suggest a thermodynamically consistent approach to the simulation of a rate dependent material response at finite strains. The nonlinear mechanical phenomena which are covered by the proposed material model include distortional, kinematic, and isotropic hardening. Firstly, we present a new two-dimensional rheological model of distortional hardening, which predicts the yield curve in the stress space to be a limac¸on of Pascal. Such effects like the distortion of the yield surface in the stress space andits orientation depending on the loading path are captured by the rheological model in a vivid way. Next, the rheological model serves as a guideline for the construction of the constitutive equations. In particular, the kinematic assumptions, the ansatz for the free energy, and the form of the yield function are motivated by the rheological model. Further, two types of flow rules are considered in this study: a normality rule and a radial rule, both thermodynamically consistent. Moreover, we formulate explicitly the constraints on the material parameters, which guarantee the convexity of the yield surface. Furthermore, implicit time-stepping methods are considered which exactly preserve the incompressibility of the inelastic flow. Finally, the basic features of the predicted material response are illustrated by a series of numerical simulations. In particular, the simulation results are compared to the real experimental data. [ABSTRACT FROM AUTHOR]

A class of quasiperiodic tilings of the complex plane is discussed. These tilings are based on β‐expansions corresponding to cubic irrationalities. There are three classes of tilings: Q3, Q4 and Q5. These classes consist of three, four and five pairwise similar prototiles, respectively. A simple algorithm for construction of these tilings is considered. This algorithm uses greedy expansions of natural numbers on some sequence. Weak and strong parameterizations for tilings are obtained. Layerwise growth, the complexity function and the structure of fractal boundaries of tilings are studied. The parameterization of vertices and boundaries of tilings, and also similarity transformations of tilings, are considered. [ABSTRACT FROM AUTHOR]

We analyze a coordinate-free tensor setting in ℝ3 within the context of the classical tensor analysis. To this end, we formulate in a basis-free manner the notions of second- and fourth-rank tensors in ℝ3, and corresponding operations on tensors. Among the large number of different approaches to the tensor setting, we give the preference to the convenient ones, concerning the specific needs of computational solid mechanics. We use the well-known Fréchet derivative to define the derivative of a function with respect to its tensor argument in a natural way. Furthermore, such aspects as the derivative with respect to a symmetric tensor argument and its uniqueness are covered in this paper. For the sake of completeness we present the coordinate representation of tensors and tensor operations. This representation is obtained in a straight-forward manner from the coordinate-free one. In particular, we elaborate the computation of the inverse of a fourth-rank tensor and the inverse of a linear transformation on the space of symmetric second-rank tensors. The tensor formalism is applied to the analysis of a nonlinear system of differential and algebraic equations governing visoplastic material response. An implicit time-stepping algorithm is formulated and the numerical treatment of the algorithm is discussed. [ABSTRACT FROM AUTHOR]

This article theoretically researches the magnetic field distribution within HGMS matrix free space - a stack of orderly placed cylinder bars. It is shown that, in near vicinity of any matrix bar, the distribution of the magnetic field practically coincides with the field distribution around a single cylinder. Relative differences of force distribution characteristic f ( x , y ) = H |grad H| are calculated for the bar stack and single cylinders depending upon the relative distance between a given field point and the axis of the bar. [ABSTRACT FROM AUTHOR]

Bchavioural contact feeding responses to various chemical incentives were studied in hybrid beluga x Russian sturgeon (Huso huso × Acipenser gueldenstaedtii) fry. Solutions of 29 amino-acids (10-2 M); aqueous extracts of various vegetable, animal and microbiological components of commercial fish diets (30 min infusion of 100 mg in 100 ml), and various artificial and natural substances were tested. The most attractive amino-acids were lysine, methionine and alanine. Most of the dietary extracts tested did not stimulate feeding behaviour, indicating that widespread commercial sturgeon diets (such as ST-07 or ST04Az) consist of components with little attractiveness for sturgeon fry. In most cases extruded diet components stimulated more bites than granulated ones. Among the diet components, only fish protein concentrate (FPC), dry milk and krill meal stimulated feeding behaviour. Flavour enhancers such as concentrated low molecular weight nitrogenous substancs (CLMNS), sodium glutamate, and ...Finnstim... all stimulated feeding behaviour of fry. Some of these substances are recommended as flavour enhancers in sturgeon diets. [ABSTRACT FROM AUTHOR]

Abstract: A new material model of finite strain metal creep is proposed. Transient effects occurring shortly after abrupt changes of the applied stress are captured by the model using the concept of nonlinear kinematic hardening. The evolution of the backstress tensor is affected by the static and dynamic recovery. In order to broaden the applicability range, the model includes the classical Kachanov‐Rabotnov damage evolution. Large strain kinematics is described using the assumption of a nested multiplicative split. The model is thermodynamically consistent, objective, and w‐invariant. The model is validated in MSC.MARC, basing on experimental data for the D16T aluminium alloy. (© 2017 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim) [ABSTRACT FROM AUTHOR]

The formation of a relatively stable high-molecular-mass product on trypsin hydrolysis of glycinin (glycinin-T) is interpreted to be a result of ‘zipper’ proteolysis. Evidence of parallel one-by-one degradation of glycinin occurring after the formation of glycinin-T is presented. At a relatively low concentration of the substrate, the one-by-one proteolysis proceeds as a first-order reaction. A method of determination of the changes in the molecular mass of a protein during the mixed-type proteolysis and some other parameters of this process is developed on the basis of the analysis of the proteolysis kinetics. The value of the molecular mass of glycinin-T calculated by means of this method makes up 70% of the initial molecular mass and coincides with the result of direct determination by gradient gel electrophoresis. [ABSTRACT FROM AUTHOR]