Main Structural Constituents Research Articles

Thoracic aortic pseudoaneurysm: Inside its pathophysiology.

Our aim was to investigate pathophysiology of pseudoaneurysm of the thoracic aorta, an acute or chronic pathology, respectively, secondary to blunt thoracic trauma and aortitis, or complicating a deep penetrating aortic ulcer, intraparietal hematoma, aortic aneurysm, and even aortic graft, often with atherosclerosis as a common background. Given the relative rarity of this disease, an "inductive" retrospective method made it possible to retrieve clinical, radiological, and histopathological elements, which were mutually compared and validated through a "deductive" process of reinterpretation. We have identified three main structural constituents of this disease: a cavity, a single blood entry port, communicating with the aortic lumen, and a pseudocapsule. It is often caused by a chronic degenerative pathology of the intima and medial layers of the aorta, typically involving elastic fibers and smooth muscle cells, with possible intermediate stages of deep aortic ulcer or intraparietal hematoma. Otherwise, the acute onset may be secondary to acute aortitis or aortic injury. Today, thanks to the current angiographic tools represented by 3-D high resolution multidetector CT and MRI angiography, the diagnosis of thoracic aortic pseudoaneurysm is easier, as well as its surgical indications.

<i>Ab initio</i> modelling of the interface energy α-Fe/Fe<sub>3</sub>c with the Bagaryatskii type orientation

Perlite is one of the main structural constituents of carbon and low-alloy steels. In it, between the bcc ferritic and orthoboric cementite phases of Fe3C, the orientational relation (OR) of Bagaryatskii, Isaichev, and Pitch can be observed. The first two, which are close to each other and are not always, repeated in the experiment, predominate in low-temperature pearlite, which has the highest strength. In this study, the simulation "from first principles" by the DFT method in the WIEN2k software package of the structure and energy of coherent α-Fe/Fe3C interfaces was carried out. The supercells were subjected to structural and volume optimization. Calculations of the surface energy of the interphase boundaries gave the values of 0.383 J/m2 for the Bagaryatskii OR and 0.594 J/m2 for the Isaichev OR. This agrees well with the existing experimental values and the results of other molecular dynamics and first-principles calculations. The difference in surface energy can play a significant role for low-temperature pearlite with a small thickness of ferrite and cementite plates and a large area of interfacial boundaries per unit volume.

Effect of carbon-fluorine additive to flux on the structure, defective substructure and fracture surface of electric arc surfacing of low-carbon wire

By the methods of transmission and scanning electron microscopy the effect of a carbon-fluorine containing additive in a flux of a silicomanganese slag with a low content of manganese oxide on the structural-phase state, defect substructure and fracture surface of an electric arc surfacing of low-alloy steel is investigated. A quantitative analysis of the parameters of structure, phase composition, dislocation substructure of the surfacing with the additive into a flux and without it is made. It is shown that the deposited metal with the additive into a flux has a layer surface structure. It is detected that a predominant fracture mechanism is a ductile fracture with a formation of the pit structure of the fracture. The areas of a quasibrittle fracture are much more rarely detected. The main structural constituent of the deposited metal are the α-phase grains. The second structural constituent of the surfacing is the pearlite grains of lamellar morphology whose relative content in the surfacing with the carbon-fluorine containing additive to a flux is three-fold higher than in the surfacing to a flux without it. In most cases the α-phase grains are fragmentary. The particles of iron carbide of a round shape of 20–80 nm in size are revealed in the α-phase grains of the deposited metal with the carbon-fluorine containing additive to a flux. The metal of the surfacing with the additive to a flux is characterized by the higher values of scalar and excess dislocation density and the amplitude of curvature-torsion of a crystal lattice.

Necessity and Feasibility of Logistics Informatization in Ceramic Industry

During past decade, following the increase in the diversity of the patterns of client expectations and its consequent rise of industrial competition for better productions and services, organizations increasingly paved the ground for higher flexibility in production lines and product development to meet the costumers' needs. But managers of many industries learned that in order to survive in the market, improving internal procedures and company's flexibility is not solely enough but material and parts suppliers must also match the company's market development policies. Competitive environment faced companies with several challenges such as reduction of production cycles, decrease in distribution time, decrease in inventories and also waiting time, which are all of high importance to maintain profitability in the market. In order to solve these problems, the process which is now referred to as Supply Chain Management was introduced; meanwhile the notion was soon spread that the real competition was not between companies but was between supply chains indeed and logistic as a part of it was remarked. In the first step, through a critical review of the literature the constituent elements of logistics costs were integrally identified and content classified. The output of this stage developed a model that represents the main structural constituent of logistics costs with associated variables. By using a questionnaire and interviewing elites the general model was then turned into a native model in the ceramic and tile industry. Then based on conceptual cost model, consisting of structures and variables, a case study on Khayyam Ceramic and Tile Company was conducted and using financial statements and interviewing relevant units within the company, a cost framework was extracted and following results were obtained. According to the study, 11% of the total costs of the company accounted for logistics costs of which, 33% was transportation costs , 39% inventory costs, 16% storage and handling costs, and 12% costumer related services and order processing.

Bioprospecting microbial hosts to valorize lignocellulose biomass – Environmental perspectives and value-added bioproducts

Current biorefinery approaches comprehend diverse biomass feedstocks and various conversion techniques to produce a variety of high-value biochemicals and biofuels. Lignocellulose is among the most abundant, bio-renewable, and sustainable bioresources on earth. It is regarded as a prodigious alternative raw feedstock to produce a large number of chemicals and biofuels. Producing biofuels and platform chemicals from lignocellulosic biomasses represent advantages in terms of energy and environmental perspectives. Lignocellulose is a main structural constituent of non-woody and woody plants consisting of lignin, cellulose, and hemicellulose. Efficient exploitation of all these components is likely to play a considerable contribution to the economic viability of the processes since lignocellulosic biomass often necessitate pretreatment for liberating fermentable sugars and added value products that might serve as feedstocks for microbial strains to produce biofuels and biochemicals. Developing robust microbial culture and advancements in metabolic engineering approaches might lead to the rapid construction of cell factories for the effective biotechnological transformation of biomass feedstocks to produce biorefinery products. In this comprehensive review, we discuss the recent progress in the valorization of agro-industrial wastes as prospective microbial feedstocks to produce a spectrum of high-value products, such as microbial pigments, biopolymers, industrial biocatalysts, biofuels, biologically active compounds, bioplastics, biosurfactants, and biocontrol agents with therapeutic and industrial potentialities. Lignocellulosic biomass architecture, compositional aspects, revalorization, and pretreatment strategies are outlined for efficient conversion of lignocellulosic biomass. Moreover, metabolic engineering approaches are briefly highlighted to develop cell factories to make the lignocellulose biorefinery platforms appealing.

Compositional Assessment of Selected Plant-based Substrates for Biogas Production

Enormous quantities of plant biomass are generated annually, as agricultural wastes. Lignocellulose is the main structural constituent of plants and represents the primary source of renewable organic matter on earth. This study was carried out to evaluate the lignocellulose composition, proximate and selected physicochemical characteristics of some selected plant-based substrates for biogas production. The substrates were: Corn cobs, Rice straw and Water hyacinth (Eichhorniacrassipes). They were collected, cut, dried for 72 hours at 320C, milled and subjected to hemicellulose, lignin and cellulose compositional analyses, using the standard Sox let extraction method. Standard methods were employed for proximate and physicochemical analyses. Results of the compositional evaluation showed that corn cob has the highest percentages of cellulose (42.0%), while extractives content was least (2.18%) in Rice straw. For the proximate analysis, the percentage carbohydrates (24.22) and ash (24.40) were highest in rice straw, while fat content had the least values of 0.65% recorded in corn cobs. The results of the physicochemical analysis showed that Rice straw had the highest values of TS (94.55%) and phosphorus (928.57mg/kg), Corn cob had the highest TVS (85.53%) and organic carbon (50.46%) while Water hyacinth recorded the highest Nitrogen content (2.33%). They are good substrates for energy generation, and lignocellulosic biomass holds a huge potential to meet the current energy demand of the modern world. The knowledge of the lignocellulosic composition of the biomass would help in choosing appropriate pretreatment measures to achieve better hydrolysis which would translate to higher biogas yield.

Rift Systems of the East Siberian Continental Margin

The structures and geological history of the shelf of the East Siberian continental margin are considered on the basis of the interpretation of seismic data along with geological data. The main structural constituents of the East Siberian Sea that were formed under the Barremian–Aptian rifting processes are described: the New Siberian rift; the Mansky, North Melville, and Drumhead rifts in the north of the East Siberian Basin; as well as the Melville depression in the south. The rifts are considered in combination with volcanic zones and the main elevations (De Long, Wrangell, Kotelnich, and Baranov). It is assumed that the rifting thinned the crust of the Podvodnikov Basin to form a large midland sedimentary basin.

Size effects in random fiber networks controlled by the use of generalized boundary conditions

Materials with a stochastic fiber network as the main structural constituent are broadly encountered in engineering and in biology. These materials are characterized by multiscale heterogeneity and hence their properties evaluated numerically or experimentally are generally dependent on the size of the sample considered. In this work we evaluate the size effect on the linear and non-linear mechanical response of three-dimensional stochastic fiber networks and determine its dependence on material parameters and on the degree of affinity of network deformation. The size effect is more pronounced in non-affine networks than in affine networks and decreases slowly when the model size increases. In order to eliminate this effect, models lager than can be effectively solved with current computers have to be considered. To address this issue, we propose a method that allows using relatively small models, while accurately predicting the small and large strain behaviors of the network. The method is based on the generalized boundary conditions introduced in (Glüge 2013, Computational Materials Science 79, 408–416), which are being adapted here to the requirements imposed by fibrous materials.

Deterministic and Explicit: A Quantitative Characterization of the Matrix and Collagen Influence on the Stiffening of Peripheral Nerves Under Stretch

The structural organization of peripheral nerves enables them to adapt to different body postures and movements by varying their stiffness. Indeed, they could become either compliant or stiff in response to the amount of external solicitation. In this work, the global response of nerves to axial stretch was deterministically derived from the interplay between the main structural constituents of the nerve connective tissue. In particular, a theoretical framework was provided to explicitly decouple the action of the ground matrix and the contribution of the collagen fibrils on the macroscopic stiffening of stretched nerves. To test the overall suitability of this approach, as a matter of principle, the change of the shape of relevant curves was investigated for changes of numerical parameters, while a further sensitivity study was performed to better understand the dependence on them. In addition, dimensionless stress and curvature were used to quantitatively account for both the matrix and the fibril actions. Finally, the proposed framework was used to investigate the stiffening phenomenon in different nerve specimens. More specifically, the proposed approach was able to explicitly and deterministically model the nerve stiffening of porcine peroneal and canine vagus nerves, closely reproducing (R2>0.997) the experimental data.

Detection of Alkali-Labile Sites on Satellite DNA by DNA Breakage Coupled with Fluorescence in Situ Hybridization (DNA-FISH) Monitor DNA Damage in Cervical Epithelial Cells

Satellite DNA is the main component of functional centromeres and forms the main structural constituent of heterochromatin. The presence of alkali-labile sites (ALSs) is a feature inherent to chromatin structure. Here we aimed to characterize ALSs in different satellite DNA loci in cervical epithelial cells using DNA breakage detection coupled with fluorescence in situ hybridization (DBD–FISH). Cervical epithelial cells embedded in an agarose matrix were deproteinized and exposed to alkaline denaturation, which generated single-stranded DNA (ssDNA) starting from the ends of spontaneous basal DNA breaks and ALSs. The amount of ssDNA produced within a specific sequence area could be detected by DBD–FISH using specific probes. The DBD–FISH signals, which were corrected for respective FISH signals during metaphase, were remarkably stronger in the 5 bp classical satellite DNA domains analyzed (D1Z1, D9Z3, and D16Z3) compared with alphoid satellite regions (D3Z1, D8Z2, and DXZ1). D1Z1 locus of chromome-1 being the most affected by alkali denaturation, and contrary, D3Z1 locus of chromosome–3 was the least sensitive to alkali treatment. These findings suggest a high density of constitutive ALSs—probably abasic sites—within the 5 bp satellite DNA sequences in cervical epithelial cells. The presence and relative abundance of ALSs might help explain the high frequency of spontaneous breakage and rearrangements in the pericentromeric heterochromatin of chromosomes 1, 9, and 16 when this chromatin region is undercondensed spontaneously or via induction, such as following viral infections. ALSs in these sequences could be useful tools to monitor DNA damage in cases of cervical carcinogenesis. ALSs on these sequences could be useful tools to monitor DNA damage in cases of cervical carcinogenesis.

Guidelines for the manufacture of heavy ductile iron castings

This study is devoted to the analysis of the impact that the basic constituents of ductile iron (carbon and silicon) and spheroidising treatment combined with inoculation exert on the final properties of heavy ductile iron castings. To evaluate the possibility of the application of ductile iron technology in the manufacture of castings for wind power plants, simulations were conducted on cast hubs of the rotor blades for wind turbines. For this type of product, it is necessary to produce castings characterised by a ferritic matrix (over 90% ferrite) and to reduce the amount of pearlite and graphite to a minimum, both of which are considered as the main structural constituents that affect the casting properties. The key guidelines for the manufacture of heavy castings from ductile iron, wind turbines included, were discussed, with particular emphasis placed on the process of spheroidising treatment and inoculation, both of which are aimed at producing in the structure of castings a spheroidal graphite of a size from 5 to 12 mm (class V to VI) and a ferritic structure in an amount exceeding 90%. This article is the result of the work done by Krakodlew S.A to implement research project No. POIG 01.04.00-12-116/12, supported by the National Centre for Research and Development and financed by the European Regional Development Fund, measure 1.4 POIG (Execution of industrial research and development in the company Krakodlew S.A., 2014).

Phytochemical analysis, nutritional profile and immunostimulatory activity of aqueous extract from Malpighia emarginata DC leaves

Abstract The research of new natural compounds known as biomolecules increasingly demonstrates the importance of the correlation between ethnopharmacological use and the scientific evidence of its therapeutic efficacy. In this study, we investigated the main structural constituents of the plant and analyzed the phytochemical profile, antioxidant activity, antimicrobial and immunostimulatory effects on Balb/c mice splenocytes promoted by the aqueous extract obtained from leaves of Malpighia emarginata DC. The nutritional analysis of the vitamins present in the aqueous extract was performed by high performance liquid chromatography (HPLC) and colorimetric methods were used for the quantification of C vitamin, elimination of ABTS radicals, nitric oxide radicals and lipid peroxidation assays. The antibiofilm assay was performed by atomic absorbance spectrophotometry, using clinically important species of Candida spp. The measurement of cytokine levels was performed by CBA technique in flow cytometry. Results showed a high presence of glucose (0.4 g/L), lignin (20%) and pectin (21%) in organic material, as well as the prevalence of Fe2+ (103.10 μg/100 g) and Mn (10.33 μg/100 g). The aqueous extract showed the presence of C and B3 Vitamins and induced a reduction of biofilm production of C. kurei and C. parapsilosis. The immunological assay demonstrated that the extract promotes an immunostimulatory and anti-inflammatory profile, with significant production of Th2 type cytokines (IL-4, IL-10 and IL-6) and a significant reduction of nitric oxide release. The aqueous extract of leaves from M. emarginata has biological potential to be used in several diseases, as well as for future pharmacological and nutritional studies.

Detection of anti-non bilayer phospholipids arragements antibodies and genotyping in patients with systemic lupus erythematosus and secondary antiphospholipid syndrome

Abstract Phospholipids are the main structural constituents of all cell membranes, their form the smooth bilayer matrix that delimited cells in which membrane proteins are located. However, some anionic phospholipids can lead to the formation of nonbilayer phospholipid arrangements (NPA) within the bilayer. NPA are transient but when they are stabilized by the drugs chlorpromazine, procainamide or hydralazine, which produced lupus-like disease in humans, they induce a disease resembling human lupus in mice. Mice present IgM and IgG antibodies against NPA which appear 4 weeks before that autoantibodies against cardiolipin, histones, nuclear and lupus anticoagulant antibodies. Mice also present histopathological abnormalities in the skin and kidneys similar to those observed in systemic lupus erythematosus (SLE). We proposed that the recognition of NPA by anti-NPA antibodies and after by the classical complement pathway causes cell lysis exposing intracellular antigens with the consequent formation of autoantibodies. Antibodies against NPA have been described in patients with SLE, lepromatous leprosy and hypertensive disorders of pregnancy. The present investigation is a clinical study not randomized, prospective, in Mexican mestizos patients of any sex and age, with SLE or with secondary antiphospholipid syndrome in which we found that the elevated levels of anti-NPA antibodies could trigger autoimmunity in these diseases and we determined that high titers lead to increased activity and correlate with the expression of HLA-DR, HLA-DQ, HLA-A, HLA-B, IL-10 (-1082G/A, -819C/T, -592C/A) and PTPN22 (+1858C/T) alleles. All clinic assays were approved by the Committee of Bioethics of our Institutions.

Microstructure of Mg-5Al-0.4Mn-xRE (x = 3 and 5 wt.%) alloys in as-cast conditions and after annealing

The microstructure investigations of two AME503 and AME505 experimental alloys in as-cast conditions and after long-time annealing were presented. The investigated materials were fabricated on the basis of the AM50 commercial magnesium alloy with 3 and 5 wt.% cerium rich mish metal. Analyses of the alloy microstructures were carried out by light microscopy, XRD, scanning and transmission electron microscopy. In as-cast conditions both the alloys were mainly composed of α-Mg, Al11RE3 and Al10RE2Mn7 intermetallic phases. Additionally, due to non-equilibrium solidification conditions, a small amount of α + γ divorced eutectic and Al2RE intermetallic phase were revealed. Long-time annealing at 473 K for 1000 h did not change the above main structural constituents. During annealing, the γ (Mg17Al12) secondary precipitation process took place in areas enriched in aluminium during solidification. The γ secondary precipitates were mainly observed in the interdendritic regions and around the α + γ eutectic.

Roasting of a sulfide polymetallic concentrate in a fluidized bed furnace

Three series of experiments on oxidizing roasting of sulfide polymetallic concentrates in a laboratory fluidized bed furnace are performed to develop an economically efficient technology of processing the sulfide polymetallic ore concentrate of the Artem’evsk deposit (Kazakhstan). The composition of the initial concentrate and the products of its oxidizing roasting are studied. The mineral composition of the concentrate is determined, and it demonstrates that this material tends toward intense spinel formation under oxidizing roasting conditions. The main structural constituents of the cinder are found to be sulfate-spinel conglomerates and oxide and sulfide particles. The possible ways of formation of these constituents are discussed using the obtained experimental data, the existing theoretical concepts, and the results of thermodynamic analysis. The calculations are performed using the FactSage software package and database. The formation of oxide and spinel components are found to be caused by both direct oxidation of sulfide minerals (primary processes) and the interaction of primary products with sulfuric anhydride and each other (secondary processes). In turn, all sulfates in the cinder are the products of secondary processes, and primary sulfate formation does not take place in roasting under the chosen conditions. Spinels cannot be completely removed from the cinder using their sulfation because of predominant consumption of sulfuric anhydride for interaction with oxide components. The optimum roasting conditions that ensure the formation of the best cinder for subsequent hydrometallurgical processing are chosen on the basis of the obtained data. The degree of extraction of nonferrous metals achieved upon leaching of the cinder is 94–96 wt %.

Uranium(VI) complex with m-hydroxybenzoic acid. Synthesis, crystal structure, and spectral properties

A new U(VI) compound with m-hydroxybenzoic acid, HIm[(UO2)(C7H5O3)3]·2H2O, was prepared. Its structure was determined by X-ray diffraction analysis and confirmed by the visible and IR spectra. The coordination number of the U atom is 8, with the hydroxyl O atom not involved in coordination with the metal ion. The main structural constituents of the compound are [(UO2)(C7H5O3)3]− anions formed by the sixcoordinate uranyl ion and three hydroxybenzoate ions acting as bidentate ligands. The imidazolium cations participate in hydrogen bonding, linking the adjacent [(UO2)(C7H5O3)3]− anions. The compound contains water molecules of crystallization, also participating in H bonding.

UV–visible and infrared absorption spectra of lead boro-phosphate glasses containing lithium oxide

Lead boro-phosphate glasses containing lithium oxide of the system xLi2O-(50-x)B2O3-40PbO-10P2O5 mol% were prepared by melt quenching technique. The infrared absorption spectra of the studied phosphate glasses indicate the presence of phosphate units with metaphosphate groups, triangular borate groups together with the sharing of PbO vibrations as the main structural constituents. The optical absorption spectra of these glasses were measured at room temperature in the wavelength range between 190 and 1100 nm. The optical band gap decreases with gradual increasing of Li2O mole content and Urbach energy of the tested glass samples increased with the increase in Li2O mol%. Density and molar volume is discussed and correlated with the structural changes within the glassy matrix.

Modulation of Neural Plasticity as a Basis for Stroke Rehabilitation

Current understanding of the mechanisms underlying neural plasticity changes after stroke stems from experimental models as well as clinical studies and provides the foundation for evidence-based neurorehabilitation. In this review, we first describe the main structural and functional constituents of neural plasticity that are believed to contribute to recovery of function after stroke. Next, we discuss selected behavioral manipulations and adjuvant therapies that can stimulate neural plasticity and improve recovery of function, particularly when applied in combination with task-specific physiotherapy and in a stimulating environment. ### Experience-Dependent Plasticity of the Cerebral Cortex Cerebral cortex is an assembly of neuronal cells that are highly interconnected. The morphology as well as function of these complex and spatially distributed networks are modulated or even controlled by the glial component of the central nervous system (CNS). The ability to adapt in response to the changing environment is the most fundamental property of the nervous tissue and constitutes the basis for learning. Neural plasticity is the neurobiological basis for the ability to adapt and learn in an experience-dependent manner.1 At the structural level, neural plasticity could be defined in terms of dendritic and axonal arborization, spine density, synapse number and size, receptor density, and in some brain regions also the number of neurons. These structural constituents of neural plasticity jointly determine the complexity of neuronal networks and their activity and contribute to recovery of function after stroke and other CNS injury. ### Spontaneous Recovery of Function After Stroke Loss of function attributable to stroke is caused by cell death in the infarcted region as well as cell dysfunction in the areas surrounding the infarct. In addition, the function of remote brain regions, including the contralateral areas that are connected to the area of tissue damage, is compromised because of hypometabolism, neurovascular uncoupling, and aberrant neurotransmission, jointly called diaschisis.1 Some recovery of function occurs spontaneously after stroke in …

Phase transformations in a corrosion-resistant high-chromium nitrogen-bearing steel

The structure, phase composition, and mechanical properties of an austenitic corrosion-resistant high-chromium nitrogen-bearing (∼0.5% N) steel are studied in the as-cast state and after homogenizing heat treatment (HT) followed by quenching. The main structural constituents of the as-cast steel are austenite and the σ phase (12%), which forms as an interdendritic metal during solidification, and δ ferrite and M 23C6-type chromium carbides are absent. Homogenizing HT at 1100–1200°C leads to the σ → γ transformation through the stage of the formation of intermediate δ ferrite via the restructuring of the tetragonal into the bcc lattice. Upon long-term homogenizing HT, the chromium concentration in ferrite decreases due to diffusion chromium redistribution and the δ → γ transformation takes place. The austenite in both the as-cast steel and the steel subjected to homogenizing HT followed by water quenching contains numerous (Cr, V)N nanoparticles. The twofold yield strength of this steel (∼400 MPa) as compared to nitrogen-free 18Cr-10Ni-type steels can be explained by not only the solid-solution hardening of austenite by nitrogen but also by precipitation hardening.

Caveolin-1 inhibits TrkA-induced cell death by influencing on TrkA modification associated with tyrosine-490 phosphorylation

Caveolin-1, a main structural protein constituent of caveolae, plays an important role in the signal transduction, endocytosis, and cholesterol transport. In addition, caveolin-1 has conflictive role in the regulation of cell survival and death depending on intracellular signaling pathways. The receptor tyrosine kinase TrkA has been known to interact with caveolin-1, and exploits multiple functions such as cell survival, death and differentiation. In this report, we investigated how TrkA-induced cell death signaling is regulated by caveolin-1 in both TrkA and caveolin-1 overexpressing stable U2OS cells. Here we show that TrkA co-localizes with caveolin-1 mostly as a large aggresome around nucleus by confocal immunofluorescence microscopy. Interestingly, TrkA-mediated Bak cleavage was suppressed by caveolin-1, indicating an inhibition of TrkA-induced cell death signaling by caveolin-1. Moreover, caveolin-1 altered TrkA modification including tyrosine-490 phosphorylation and unidentified cleavage(s), resulting in the inhibition of TrkA-induced apoptotic cell death. Our results suggest that caveolin-1 could suppress TrkA-mediated pleiotypic effects by altering TrkA modification via functional interaction.