This article illustrates the impact of basalt filler, both in the form of basalt flakes and basalt fibers, on thermal and mechanical properties, as well as on the fire hazard, of silicone rubber (SR) composites, including ceramizable composites. In addition to basalt filler, ceramizable composites contain mineral fillers in their composition in the form of silica and calcium carbonate, inorganic fluxes such as zinc borate and glass frit, and melamine cyanurate as a flame retardant. The obtained composites were analyzed from the point of view of their morphology, rheological and thermal properties, flammability, and mechanical properties before and after the ceramization process. The obtained research results indicate that the basalt filler has an unambiguous impact on the improvement of thermal properties and the reduction of flammability in the analyzed composites. The results of morphological analyses of ceramizable composites before and after the process of their ceramization indicate a definite impact of the basalt filler on the structure of the formed ceramic layer. An increase in its homogeneity exerts a direct impact on the improvement of its mechanical parameters. Ceramizable composites are new polymer materials that are either non-flammable or characterized by a reduced flammability and are intended, above all, to protect copper wires in electrical cables against melting resulting from fire or high temperature by forming a protective ceramic layer. During regular usage, they are characterized by properties similar to conventional elastomer composites, whereas in the case of fire they are transformed into an insulating ceramic layer of a specific porosity and mechanical durability, which ensures the integrity of the electrical circuits for a minimum period of 120 min from the point at which flame appears. Although ceramizable materials may be obtained through the application of various polymers, e.g., EVA , PE 4],,4], SBR The review of the source literature on the subject leads to the conclusion that the high resistance of silicones to fire is mainly related to the formation, during their thermal decomposition, of a boundary layer composed of silica with a high thermal capacity, which to a considerable degree makes conducting heat between the flame and the sample difficult. On the other hand, the cohesive forces between the particles of silica are insufficient for the formation of an effective barrier impeding the mass flow between the sample and the flame ,13. HencThere are numerous mechanisms responsible for the ceramization process. The most important ones include:Formation of physical connections between thermally stable particles of mineral fillers, which are performed by low-temperature fluxes, such as: glass frits, which are characterized by a melting point at a level of 374–525 °C ,15, boroFormation of silicate bridges between the particles of silica, resulting, among other things, from the decomposition of silicone rubber, and other mineral fillers introduced into the SR matrix. In this mechanism, the key role is played by a good adhesion between silica particles and thermally stable particles of mineral fillers.Sintering of mineral filler particles occurs through the condensation of hydroxyl groups present on their surface. This mechanism takes place when the content of the mineral fillers in the SR rubber matrix is high.“In situ” formation of new mineral phases as a result of chemical reactions takes place between the particles of mineral fillers. This mechanism can be exemplified by the reaction between calcium oxide and silica, leading to the formation of calcium silicates, which positively influence the mechanical parameters of the formed ceramic structure .The basic problem that limits the industrial application of ceramizable composites is not only their reduced resistance to fire and elevated temperatures, but also the insufficient mechanical parameters (mainly compression strength) of the formed ceramic structure. It can be seen in the source literature that the existing research works were intended to both increase the fire resistance of ceramizable composites and to improve the mechanical parameters of the ceramic layer formed as a result of their thermal decomposition .3 takes place within the temperature range of 300–600 °C, forming new products, i.e., AlPO4 and NH4AlP2O7, which, when subsequently reacted with mica at a temperature of 800 °C, are responsible for the formation of KAlP2O3 and Al2O3 × 2SiO2. An increase in the temperature above 1000 °C leads to the formation of KAlSi3O8, which imparts a specific bending resistance to the formed ceramic layer [From the literature review, it follows that Hu et al., when analyzing the impact of the combination ammonium polyphosphate/aluminum hydroxide/mica, stated that the decomposition of APP (ammonium polyphosphate) and Al(OH)ic layer . Lou et ic layer . In our ic layer . We alsoic layer .The present article illustrates the results of research regarding the impact of the basalt filler, both in the form of basalt flakes and basalt fiber, on the properties of silicone rubber ceramizable composites.The literature on the subject comprises a few papers regarding the impact of the basalt fiber on the properties of epoxy resin ,23 or po−1). The rubber was cross-linked with the use of dicumyl peroxide from Sigma Aldrich  in a quantity of 2.5 parts by wt./100 parts by wt. of the rubber.The polymer matrix was methylvinylsilicone rubber (SR), made by Silikony Polskie  with a vinyl group content of 0.05–0.09% ); melamine cyanurate (MC) ; calcium carbonate anhydrous, free-flowing, reagent ≥99% . The ceramization-promoting glass frits “A 2120” with chemical composition (wt.%): 7.3CaO-25Na2O-2.1K2O-4.2Al2O3-61.4SiO2 and a softening point temperature of 540 °C was obtained from from Reimbold & Strick GmbH, Cologne, Germany; zinc borate ZnO ≥ 45%, B2O ≥ 36% was obtained from Sigma-Aldrich ; basalt flakes (BLF) and basalt fibers (BFS) ) (The following compounds were used as fillers in the rubber blends: Aerosil 200 fumed silica (BET specific surface area 175–225 melgium)) .The composite mixes  were prePhotographs of BFL and BFS were obtained through the use of a TPL Trino stereoscopic microscope equipped with a DLT-Cam PRO 5 MP camera and a scanning electron microscope (SEM), model TM3000 from Hitachi . −1.The thermal properties of the rubber composites were tested under air atmosphere at temperatures ranging from 25 to 700 °C with the use of a thermal analyzer . The weighted portions amounted to about 5–10 mg. The investigated samples were analyzed at a heating rate of 10 °C min−2. During the tests, the following parameters were recorded: initial sample weight, time to ignition (TTI), sample weight during testing, total heat released (THR), effective combustion heat (EHC), average weight loss rate (MLR), heat release rate (HRR), final sample weight.The flammability of the composites was determined using a cone calorimeter . Composite samples with dimensions of (100 × 100 ± 1) mm and thicknesses of (2 ± 0.5) mm were tested in a horizontal position with a heat radiant flux density of 35 kWmCeramization of the vulcanizates was performed in a laboratory furnace by Nabertherm with the P320 controller . Cylindrical samples  of the ceramizable composites were heated in 3 different conditions: (1) 1100 °C—from room temperature to 1100 °C in 30 min (heating rate 35 °C/min); (2) 950 °C—from room temperature to 950 °C in 120 min , and (3) 550–1000 °C—from room temperature to 550 °C in 53 min (heating rate 10 °C/min), 10 min of isothermal conditions at 550 °C, and end heating from 550 to 1000 °C in 27 min at the (heating rate 16 °C/min)—total time 90 min.The micromorphology of the composites was examined before and after ceramization by means of scanning electron microscopy (SEM) Joel JSM-6400  with Noran energy-dispersive X-ray spectroscope unit (EDS) . The sample cross-sections were prepared by crushing in liquid nitrogen and gold sputtering directly before measurement.The mechanical properties of the composites were tested by means of a Zwick/Roell 1435 static testing machine , measuring stress at different degrees of elongation , tensile strengths (Ts), and elongations at break (Eb).The compression strength of the composites after their ceramization  was tested in the diameter direction by means of a Zwick/Roell Z 2.5 device.05 and t09) of the SR composites, including the ceramizable composites.The introduction of the basalt filler, both in the form of basalt flakes (BFL) and basalt fiber (BFS) has practically no influence on the values of scorch time of the SR rubber composites. On the basis of the data shown in 09 of the SR-4 compound, with reference to the other samples, is related to the specific behavior of the rubber and the long fibers during testing. At the beginning of the kinetic of vulcanization test, only uncured viscous rubber responds to the externals stress applied by the rheometer. Uncured rubber of low viscosity moves easily around the large fibers, which do not take part in carrying stress. When the rubber starts to cure, it is no longer able to flow viscously, and starts to transfer the stress to the long and stiff fibers, resulting in a significant increase of torque. This effect gives a much higher torque value than the hydrodynamic effect of the dispersed particulate fillers  undergoes a clear two-step thermal decomposition. The first step, which begins at a temperature of T = 335 °C, and whose maximum rate of thermal decomposition at a temperature of T = 383 °C amounts to 0.98%/min, is related above all to the reactions of depolymerization and degradation of SR rubber to low-molecular-weight cyclic volatile compounds. The second step of thermal decomposition, whose beginning is registered at a temperature of T = 420 °C, and whose maximum rate at a temperature of T = 516 °C amounts to 7.15%/min, is related to the reactions of both degradation and thermal destruction  13,25,2,225,26.The radical mechanism constitutes the dominant mechanism of decomposition of the cross-linked silicone rubber. An increase in temperature results in homolytic random dissociation of the Si-C bonds in the backbone polymer chain, as a consequence of which the resulting macroradicals, undergoing the subsequent reactions of recombination and cross-linking, reduce the elasticity of the polysiloxane chain, and hence the efficiency of formation of low-molecular-weight cyclic compounds, with reference to the first step of thermal decomposition.Both the first and the second step of thermal decomposition of the cross-linked SR rubber are accompanied by a strong exothermic effect registered on the curve DSC . The intIt should be clearly emphasized that only 15 parts by weight of the basalt filler definitely increases thermal stability of the cross-linked SR, expressed both by the temperature of the sample at 5 and 50% mass loss, and by the maximum temperature of the first and second steps of thermal decomposition, the maximum rate of the sample mass loss, and the residue after thermal decomposition at a temperature of T = 650 °C , Table 4650 also increases. Thermally stable basalt, not undergoing any thermal transformations, positively influences the structure of the boundary layer which is formed during the thermal decomposition and combustion of the analyzed composites, and which efficiently impedes the flow of mass and energy between the sample and the flame. A higher value of the parameter P650 of the composite SR-4, which contains basalt fiber, with reference to the composite SR-3 containing the same number of basalt flakes, is due to a larger size, and hence worse distribution of BFS in relation to BFL in the polymer matrix.It is also worth noting that, together with an increasing content of the basalt filler in the composite, the value of the parameter PThe introduction of mineral fillers into the silicone rubber matrix—ceramizable composites SR-5÷SR-9—does not, in principle, change the nature of thermal decomposition of the SR rubber .exo- to endothermic  is accompanied by radical extension of the time to flameout (parameter tf-o), which indirectly confirms the intensity of the combustion process of a given material  and basalt fiber (BFS), clearly reduces the fire hazard of those vulcanizates that contain them. The introduction of only 15 parts by weight of basalt flakes into the silicone rubber matrix leads to an increase in the time to ignition from 115 to 145 s. Increasing the concentration of the basalt filler to 20 parts by weight, both in the form of basalt flakes and basalt fiber, extends the time to as much as 190 s. An increase in the value of the parameter tmaterial .max (maximum heat release rate) is a key magnitude illustrating the rate of thermal decomposition and combustion of the marked composites. It should be clearly noted that the introduction of 15 parts by weight of BFL into the silicone rubber matrix results in a reduction of the value of the parameter HRRmax from 134.7 kW/m2 to 96.2 kW/m2. An increase in the content of BFL in the SR matrix to 20 parts by weight causes a reduction of the value of the parameter HRRmax by as much as 63.9%, i.e., to a value 48.5 kW/m2  and 66.7% (EHC) was obtained with regard to the reference composite SR-1 .max, AMLR (average mass loss rate of the sample with respect to its surface), FIGRA (fire growth rate) or MARHE (maximum average rate of heat emission).At present, from the point of view of fire hazard, a lot of attention is being paid to the parameters directly reflecting the rate of fire development, i.e., tHRRmax parameter as compared with the reference sample SR-1. The FIGRA parameter, determined as a quotient of the value of HRRmax and the time necessary to obtain the maximum heat release rate HRRmax, which is a typical indicator illustrating the fire growth rate for a specific material exposed to a defined heat flux, in the case of composites containing both BFL and BFS assumes decisively lower values in comparison with the composite SR-1.The composites containing 30 parts by weight of both BFL (SR-3) and BFS (SR-4) are characterized by a considerably higher tHRRThe data included in The parameters AMLR and MARHE also indicate an effective flame retardant effect of the basalt filler.It should be emphasized with clarity that slightly worse values of the fire hazard parameters of the composite containing BLS (SR-4), with reference to BFL (SR-3), are related to their larger size of fibers in comparison to basalt flakes, and thus their worse dispersion in the silicone rubber matrix . A more i. A reduction of flammability of the composites of silicone rubber containing the basalt filler is, however, a result of the high thermal stability of basalt and its suitability for the formation of an insulating boundary layer, effectively reducing the flow of mass and energy between the sample and the flame.The flame retardant activity of the basalt filler is a result of both its high heat capacity and high thermal stability. Basalt, by absorbing heat radiation energy, acts as a thermal shield protecting the polymer against the subsequent reactions of degradation and thermal destruction, which is proved, among other things, by an increase in the value of the parameter time to ignition tThe images illustrating the remains after the burning of the composites SR-1, SR-3 and SR-4, respectively, clearly indicate that under the white residue consisting of silica, there exists a homogenous basalt layer .Reviewing the source literature on the subject leads to the conclusion that the forces of cohesive interactions between silica particles resulting from the decomposition of SR are insufficient for the formation of a condensed boundary layer ,25. Thismax of the composite SR-8 was reduced by 45.4% in comparison to the reference ceramizable composite SR-5, while the parameter tHRRmax increased from 410 s in the case of the composite SR-5 to 990 s for the composite SR-8. It is worth emphasizing that an increase in the value of the parameter tHRRmax is proportional to the content of the basalt filler in the composite. Also, the other parameters of fire hazard, such as THR, EHC, AMLR, FIGRA, MARHE, are closely correlated with the amount of BFL in the SR rubber matrix  than in the SR rubber matrix alone (composite SR-4)  .max, THR and FIGRA for the composite SR-8 in comparison to SR-9 result from smaller sizes and, consequently, better distribution of BFL in relation to BFS , it was concluded that in the presence of basalt flakes, the degrees of aggregation of silica, calcium oxide, zinc borate and aluminum oxide are considerably lower. It is probably that the basalt filler, which is characterized by both high heat capacity and large particle size, reduces the processes of formation of so-called filler islands, thus contributing towards the formation of a homogeneous solid ceramic layer .b. It should also be noted that, in contrast to BFL, basalt fibers considerably worsen the mechanical parameters TS and Eb of composite SR-4 relative to the reference composite SR-0. This is, above all, related to the large size of the fiber and its poor distribution in the SR rubber matrix.The introduction of the basalt filler, both in the form of basalt flakes (BFL) and basalt fibers (BFS), into the silicone rubber matrix ambiguously influences the mechanical parameters of the obtained SR composites . In the b (%) of ceramizable composites. In the presence of mineral fillers, which increase the distances between the basalt particles dispersed in the rubber matrix, no spatial structures are formed that could strengthen the studied ceramizable composites.The basalt filler has practically no impact on the values of the parameters TS (MPa) and EIt should be noted that the basalt filler, both in the form of BFL and BFS, considerably strengthens the formed ceramic structure . The comIt cannot be excluded that the basalt filler, due to its high thermal capacity, catalyzes the processes of melting and flowing of both zinc borate and glass frit, as well as the sintering of mineral fillers contained in the composite .Extreme conditions of ceramization (heating to 1100 °C) result in the studied composites swelling strongly under the influence of the released gaseous products of thermal decomposition. However, the formed ‘honeycomb’-type ceramic structure is characterized by a very high degree of hardness. These samples could not be examined, owing to the limited measurement range of the durometer.The obtained research results regarding compressive strength of the ceramic structure are compatible with the results obtained by Mansour et al. The ceramic layer formed as a result of the decomposition of ceramizable composites of SR rubber, at a temperature of T = 1000 °C, is characterized by a higher value of the force at bending than that obtained at T = 600 °C . SimilarAn improvement of the thermal properties of the composites containing basalt is related to both the adsorption of polymer chains on the basalt surface and the high thermal capacity of basalt.Increased polymer–filler interactions lead to a considerable reduction in the segment mobility of the polymer chains, and thus a reduction in the efficiency of the reaction of decomposition and chain transfer. In addition to this, basalt, by absorbing significant amounts of heat, acts as a thermal shield, which protects the composite against the processes of both degradation and destruction.The reduction in the flammability of the silicone rubber composites containing basalt filler is, above all, a result of its high thermal stability and suitability for the formation of an insulating boundary layer that effectively reduces the flow of mass and energy between the sample and the flame.The introduction of basalt flakes does not significantly influence the image of ceramic structures obtained using the SEM method. In the presence of basalt flakes, however, the degree of aggregation of silica, calcium oxide, zinc borate or aluminum oxide is considerably lower. It is probably that the basalt filler, which is characterized by high thermal capacity and large particle size, decreases the processes of the formation of the so-called filler islands, thus contributing towards the formation of a homogeneous solid ceramic layer, characterized by considerably better mechanical parameters in comparison to the reference composite.


The role of the ligaments is fundamental in determining the spine biomechanics in physiological and pathological conditions. The anterior longitudinal ligament (ALL) is fundamental in constraining motions especially in the sagittal plane. The ALL also confines the intervertebral discs, preventing herniation. The specific contribution of the ALL has indirectly been investigated in the past as a part of whole spine segments where the structural flexibility was measured. The mechanical properties of isolated ALL have been measured as well. The strain distribution in the ALL has never been measured under pseudo-physiological conditions, as part of multi-vertebra spine segments. This would help elucidate the biomechanical function of the ALL. The aim of this study was to investigate in depth the biomechanical function of the ALL in front of the lumbar vertebrae and of the intervertebral disc. Five lumbar cadaveric spine specimens were subjected to different loading scenarios  using a state-of-the-art spine tester. The full-field strain distribution on the anterior surface was measured using digital image correlation (DIC) adapted and validated for application to spine segments. The measured strain maps were highly inhomogeneous: the ALL was generally more strained in front of the discs than in front of the vertebrae, with some locally higher strains both imputable to ligament fibers and related to local bony defects. The strain distributions were significantly different among the loading configurations, but also between opposite directions of loading . This study allowed for the first time to assess the biomechanical behaviour of the anterior longitudinal ligament for the different loading of the spine. We were able to identify both the average trends, and the local effects related to osteophytes, a key feature indicative of spine degeneration. The anterior longitudinal ligament (ALL) is a fundamental component of the spine. It covers the anterior aspect of the spine running along the entire length of the spine . To elucin vitro in detail [in vitro tests [The biomechanical function and strain distribution in the vertebrae and IVD have been investigated n detail –7. Oftenn detail  whereas ro tests  for the ro tests –12 and/oro tests –15 underThe investigations on the spinal ligaments are somehow limited. Specifically, the ALL, which is one of the strongest ligamentous structure in the spine, has only partially been investigated so far. Generally, the ALL was tested separately at the tissue level: evaluating the mechanical properties of dissected tissue specimens –18, and In this work, the evaluation of multi-vertebra spine segments  through flexibility tests was integrated with a full-field measurement of the strain distribution of the anterior surface –26. The Specifically, we aimed measuring the strain distribution in the ALL for different directions of motions under pure moments, and so understanding how the strain distribution changes through the progression of the loading cycle analyzing discrete steps.We hypothesized the ALL undergoes non-uniform strain distribution when the spine segment is subjected to pure moments, potentially related to the unique specimens’ anatomy/morphology (e.g.: presence of osteophytes); moreover, opposite loading directions  translate to non-mirrored strain distributions.This study was approved by the Institutional Review Board (Ethikkommission) of Ulm University, . In order to investigate the strain distribution on the anterior longitudinal ligament in the lumbar region, cadaveric multi-vertebra spinal segments were subjected to non-destructive pure moments in different directions, with a state-of-the-art spine tester. The tests were performed twice on each specimen under identical conditions. Preliminarily, the range of motion was measured, with an optical motion tracking system, to allow comparisons of the tests results. Subsequently, the strain distributions on the anterior surface of the L3-L5 region, were measured by means of digital image correlation (DIC) with a recently validated protocol, for identifying stretched/compressed regions. The strain distributions were analyzed firstly qualitatively, and then quantitatively.Five fresh-frozen human thoracolumbar spine segments were obtained through an ethically-approved international donation program . The donors were all Caucasian, three males and two females . InclusiThe volumetric CT reconstructions of the specimens are available in the The soft tissues  on the anterior side of the spines were carefully removed to expose the anterior longitudinal ligament and the lateral side of the vertebral bone and of the intervertebral discs; the posterior elements were left in place . The uppAll specimens were tested at room temperature (ca. 23°C) and the hydration was preserved spraying saline solution during the tests. In order to mount the specimens in a universal spine tester, flanges were fixed to the PMMA blocks ,29 so thThe coordinate system of  was usedIn order to confirm that the overall kinematics of the specimens was consistent with the literature, the mechanical tests were first performed with a motion tracking system. Each single vertebra was equipped with three spherical reflective markers, which were attached frontally and laterally to the vertebral body. The motion of the single vertebrae was simultaneously captured with six cameras of the optical system , synchronized with the mechanical loading apparatus. After evaluating the relative intervertebral motions using the software Nexus 1.8.5 (Vicon Motion Systems Ltd.), the kinematic data were matched with the moment data to analyze the resulting load-deformation curves. The global range of motion (ROM) as well as the global neutral zone (NZ) of each motion segment between T12 and the sacrum were quantified using dedicated scripts .In order to measure the full-field strain distribution on the anterior spinal ligaments, the same mechanical tests were performed while a 3D DIC system was used. A white-on-black speckle pattern was prepared before the test on the anterior surface of the specimens following an optimized procedure . The darThe DIC system  was configured with two 5 Mpixels cameras  equipped with high-quality metrology-standard 17 mm lens  to acquire images of the specimens providing a stereoscopic vision. A directional custom system of LEDs  was placed to light up the specimen with oblique light minimizing the glares on the specimen typical of direct illumination. The cameras were placed at a distance of 540 mm from the specimen. The cameras were aligned vertically in order to take advantage of the sensor shape in framing the region of interest (ROI) of the spine segment  without scarifying the measurement spatial resolution, 1) and minimum (eps2) engineering principal strains, as well as their direction, were computed using a facet size between 39 and 59 pixels, a grid spacing between the facets of 4 pixels and contour smoothing with a kernel size of 5x5 facets.To enable the stereoscopic reconstruction within the measurement volume and correct the distortion of the lenses, a calibration was performed before each acquisition using a proprietary calibration target . The analysis of displacements and strains through correlation of the images was achieved using the proprietary software Istra 4D . The maximum  range of motion (ROM) was defined as the maximum deflection of the respective motion segment at full load (7.5 Nm). The global neutral zone (NZ) was evaluated as the difference of the angle at 0 Nm of the hysteresis cycle. The NZ specifies the motion of the specimen in the unloaded region, representing the laxity .1 and eps2 maps were computed by the DIC system during the entire load cycle (https://doi.org/10.6084/m9.figshare.11397951). For a qualitative analysis, the strain maps, in the region of interest from L3 to L5 were reported for each loading scenario during the progression of the load.The full-field eps1 and eps2, for each specimen. Similarly, to describe how the principal strains were distributed in the cranio-caudal direction of the ALL in front of the vertebra and in front of the IVD, the median over circumferential  lines were computed, separately, over the vertebra and over the IVDs. Then, the data from the five specimens were pooled and the median trend plotted together with the standard deviation. As the sub-ROIs were dimensionally different in the different specimens and the number of measurement points is connected with the physical dimension of the spine segments, the data were re-sampled over the same number of points. In order to assess the significance of alterations of such distribution of strain in relation to the different loading scenarios, a two-sample Kolmogorov-Smirnov test was applied both to the circumferential and cranio-caudal strain distributions of the L4 vertebra and the caudal IVD, discriminating the opposite directions of loading.For a quantitative analysis, two sub-regions of interest (sub-ROIs): in front of the L4 vertebra and in front of the L4-L5 IVD, were defined. For each sub-ROIs, the strain field at the maximum load was analyzed through a MatLab script computing the principal strains medians. To assess the significance of the difference between the strains in front of the vertebra and in front of the IVD, the medians over such areas were compared with the two-sample Mann-Whitney test for each loading scenario. To describe how the principal strains were distributed in the circumferential direction of the ALL in front of the L4 vertebra and in front of the L4-L5 IVD, the median over cranio-caudal  lines were computed, separately, over the vertebra and over the IVD, both for epsAll the tests were successfully performed with no visible damage of the specimens. A preliminary check of the bending moment-rotation plots from the spine tester confirmed that the difference between the two series of loading cycles  were smaller than 5° with a rotation of 33° at full load. The only problems encountered was the poor correlation for flexion-extension for specimen #1 and the loss of the dataset of specimen #4 for extension.An in-house validation showed that the motion tracking system has an accuracy of better than 0.1 mm and better than 0.1°. The zero-strain tests, before each test, indicated that DIC-measured strains had a systematic error lower than 20 microstrain and a random error lower than 60 microstrain.The median global ROM between T12 and the sacrum at 7.5 Nm was 12.0° in flexion-extension (range: 9.7°–14.6°), 13.6° (range: 12.4°–24.9°) in lateral bending and 7.8° in axial torsion (range: 4.6°–9.3°). The global NZ between T12 and the sacrum was 3.7° in flexion-extension (range: 1.9°–5.9°), 6.2° in lateral bending (range: 4.4°–20.1°) and 0.8° in axial torsion (range: 0.2°–1.8°).The full-field strain maps showed a non-homogeneous distribution in the ALL Figs –7. The pWhile common trends were visible in all specimens, inter-specimen differences were found in association with specific bony-defects and individual defects highlighted by the CT images .1 and eps2 over the portion of the ALL in front of the L4 vertebra were respectively 3910 microstrain and -15170 microstrain (median between 5 specimens); in front of the IVDs eps1 and eps2 were respectively 19160 and -23020 microstrain. At the maximum extension, the median eps1 and eps2 in the ALL in front of L4 were respectively 13890 microstrain and -1890 microstrain (median between 5 specimens); in front of the IVDs eps1 and eps2 were respectively 18730 and -10710 microstrain. The only significant difference was found for flexion between eps1 in front of the IVDs and in front of the L4 vertebra  and longitudinal direction in the tensile side .During the application of lateral bending , strains1 circumferentially the vertebra; the distribution over the IVD were significantly different, with the exception of eps2 circumferentially the IVD , which could act as strain concentrators cranially, while shielding the strains in the ALL surrounding them. The L4-L5 segment had a score for the osteophyte formation of 11 points, equivalent to a Grade 2. The DIC analysis showed an intensification of the strains in front of L3-L4 and L4-L5 IVDs, in the most cranial portion of the disc, and areas with much lower strains caudal to these spots.Specimen #4: this specimen was mildly scoliotic with a Cobb angle T12-L5 of 10° and concavity on the right side. The DIC analysis showed a non-mirrored strain pattern between right and left lateral bending, and between clockwise and counterclockwise torsion. Furthermore, it had several osteophytes at all endplates. The L4-L5 segment had a score for the osteophyte formation of 15 points, equivalent to a Grade 2. The DIC analysis revealed strain concentrations near such osteophytes. The largest osteophyte projected upwards from the central-left margin of the superior endplate of L5 partially covering the caudal portion of the L4-L5 IVD. In this area a strain attenuation was visible in the area where the osteophyte covered the IVD, especially for flexion.Specimen #5: the CT images showed that this specimen had prominent osteophytes on the right and left sides of the cranial endplates of L5. The L4-L5 segment had a score for the osteophyte formation of 17 points, equivalent to a Grade 3. The strain distributions showed an intensification in the right and left areas circumferentially the L4-L5 IVD in flexion.More details about the individual specimens, the distribution of strains of the vertebrae and IVD in the circumferential and cranio-caudal directions can be found in the The aim of this work was to explore the biomechanical behaviour of the most superficial layer of the anterior longitudinal ligament focusing on the anterior aspect of the lumbar vertebrae and intervertebral disc, applying a new paradigm. Structural flexibility tests and local strain analysis were performed on the anterior surface of spine segments loaded in flexion/extension, lateral bending and torsion. The hypotheses of the work were that: (i) the strain field on the surface of the ALL is not homogeneous between different regions ; (ii) the strain distribution is not homogenous within each such region, possibly due to specific bony-defects; (iii) inside the same region the strain field depends on the different loading scenarios; and (iv) opposite directions of loading translate to non-mirrored strain distributions.In order to test these hypotheses, segments of multi-vertebra human spine segments, to reproduce a better loading transmission on the ALL, were used. Each specimen was tested in flexion/extension, lateral bending and axial torsion up to 7.5 Nm with a state-of-the-art spine tester . The gloThe global range of motion under load and the evaluation of the neutral zone, for the different loading scenarios, confirmed the typical trend and values for human lumbar spine, as reported in the Busscher et al. work ,35. Theyin vivo depending on the region where it is attached (IVD or vertebra) [The most strained portion of the ALL superficial layers was in front of the IVDs with a strain magnitude that was between 1.15 and 8.12 times larger than in front of the vertebrae Figs  and 6; tertebra) ,16. As tAlso in extension the ALL in front of the IVD and of L4 underwent an appreciable longitudinal strain, confirming the important mechanical role of ALL in constraining extension, in conjunction with the action of the facet joints .Lateral bending seemed to be the loading scenario that strained less the ALL in terms of absolute values of strains. This is due because the ALL covers the regions in proximity of the neutral axis for lateral bending. Nevertheless, the strain distribution during right and left lateral bending was rather mirrored with respect to the vertical axis in front of the disc but not in front of the vertebra Figs . While tThe torsional scenario was associated with large strains in the ALL, with smaller differences between the regions in front of the vertebrae and of the IVD . The lacin situ under pure tension, after removal of the IVD. The evaluation of the tensile strain was performed on macro-regions of the ALL: insertions and free-length, in the cranio-caudal direction of the ALL; outer and central regions, circumferentially the ALL. They showed larger strain in the substance and outer regions of the ligaments, similar to the present study. [To the best authors’ knowledge, this is the first work where the full-field strain distributions were computed on the ALL in lumbar spine segments. Previous works explored the mechanical behaviour of ALL through strain analysis. ,21 measut study. ,23,43 evOther works studied the mechanical properties of the ALL removing it from the spine and testing it in pure tensile tests. These conditions were far from the scenarios implemented in the present study; nevertheless some qualitative comparisons are possible. –18 reveaA limitation of the present work is the sample size: five specimens have a limited statistical power. It worth noticing that the results here reported are in agreement with the kinematics data reported for a larger specimens’ cohort . As thisSome specimens showed some typical defects of elderly donors, such as osteophytes and consequent disc degeneration. Our detailed DIC strain investigation on the region of interest allowed identifying the associated perturbations on the strain distributions. However, some of the results may be biased by a relatively high BMI of the donors, and a relatively low BMD. While the present findings are directly applicable to spines of subjects with similar BMI, an extension to cases with normal BMI is possible because the donors were physically active until death, and therefore their ALL can be expected to have normal mechanical properties. Conversely, slightly different behaviour would possibly be observed in healthier spines with different BMD: the bone/ligaments insertions would play a fundamental role, in particular their stiffness could modify the local behaviour of the ALL.in vitro reproducing relevant loading conditions [The experimental setup had intrinsic limitations such as the reduced loading rate, which is far from physiological . This wanditions . Furthernditions –48.The accuracy and precision of the DIC was optimized for each acquisition; however, testing fresh specimens entailed leakages of biological fluid that can lead to some local loss of correlation . In the This is the first time that the distribution of strain in the anterior longitudinal ligament was measured in multi-vertebra intact spine segments. The obtained results showed the non-uniform strain distribution, under the different loading scenarios. The vertebrae and intervertebral discs, with their peculiar defects  played a fundamental role in defining the behaviour of the ALL. The current analysis including a spine tester and an unpreceded measurement of the strain distribution is so detailed that not only we could investigate the average effects of the different loading scenarios, but also the local effect that subject-specific defects may have on strain distribution. These results suggested again the importance of a full-field strain analysis to understand the biomechanics of the human spine and the interaction between different tissue types. This work could be the starting point for future studies where the effect of surgical procedures will be compared with intact spines.S1 FigFor each specimen  the following are reported:• Left: An image of the specimen with an indication of the vertebrae and disc under consideration, and of the sub-ROIs where strains were computed along and around the ALL in front of the L4 vertebra and in front of the L4-L5 IVD.1) and minimum (eps2) engineering principal strains are shown in the top images. Below each loading scenario, the distributions of the maximum (eps1) and minimum (eps2) strains are plotted around and along the ALL, both in front of the L4 vertebra and of the L4-L5 IVD.• For each loading scenario, the maps of the maximum , 2  or 3  according to 1) and minimum (eps2) engineering principal strains) both in front of the L4 vertebra and in front of the L4-L5 IVD, for each loading scenario .The table at the bottom right reports the median strains (maximum (eps(PDF)Click here for additional data file.S1 DatasetThe maximum (eps1) and minimum (eps2) principal strains measured through the Digital Image Correlation on each specimen were reported with their spatial coordinates.(XLSX)Click here for additional data file.S2 DatasetThe spatial coordinates of the regions of interest in front of the vertebra and the in front of the intervertebral disc were reported for each specimen for each loading condition in both the directions.(XLSX)Click here for additional data file.


It is established that the diffusion permeability of AEMs increases with dilution of the ampholyte solutions, while it decreases in the case of the strong electrolyte solution. The factors causing the unusual form of concentration dependencies of AEMs in the ampholyte solutions are considered: (1) the enrichment of the internal AEM solution with multiply charged counterions and (2) the increase in the pore size of AEMs with dilution of the external solution. The enrichment of the internal solution of AEMs with multiply charged counterions is caused by the Donnan exclusion of protons, which are the products of protolysis reactions. The increase in the pore size is conditioned by the stretching of the elastic polymer matrix due to the penetration of strongly hydrated anions of carbonic, phosphoric, and tartaric acids into the AEMs.The concentration dependencies of diffusion permeability of homogeneous (AMX-Sb and AX) and heterogeneous (MA-41 and FTAM-EDI) anion-exchange membranes (AEMs) is obtained in solutions of ampholytes (sodium bicarbonate, NaHCO The extraction of valuable components and nutrients from urban and industrial sewage and liquid animal wastes, as well as from wastewater of food and pharmaceutical industries, is one of the main trends in modern membrane technology ,2,3. The2, Na2SO4, etc.). A review of these work is given in [The development of such technologies is constrained by several challenges. The first of them is related to fouling and destruction of ion-exchange membranes during their long-term operation ,12,13,14given in .+ form or the AEM is in the OH– form, the zwitterionic forms of the amino acid acquire an electric charge opposite to the charge of the fixed groups of the membrane and are easily transported through the membrane as counterions [It is known that the permselectivity of membranes is mainly determined by their electrical conductivity and diffusion permeability ,19,20,21nterions . This phnterions  or assisnterions  of aminonterions ,31.3 and NaH2PO4) and compare them with similar dependencies obtained in solutions of sodium chloride (NaCl) and discuss the reasons for the different behavior of membranes in solutions of strong electrolytes and ampholytes.In this paper, we analyze the concentration dependencies of the integral coefficient of diffusion permeability of homogeneous and heterogeneous AEMs in solutions of potassium hydrotartrate (KHT) and sodium salts of carbonic and phosphoric acids (NaHCOThe homogeneous (AX and AMX-Sb) and heterogeneous (MA-41 and FTAM-EDI) anion-exchange membranes are studied. Some of their characteristics are shown in Prior to conducting the investigation, the membranes underwent the pre-test salt treatment  and were–1; pH = 5.7 ± 0.2). Crystalline sodium chloride (NaCl), sodium bicarbonate (NaHCO3), monosodium phosphate (NaH2PO4·2H2O), and potassium hydrotartrate  of analytical grade  were used. The pH values of the investigated aqueous solutions are summarized in The solutions were prepared using deionized water  of the membranes was determined by substituting chloride ions with nitrate ions [The ate ions .thickness of the membranes (d) was measured using the high-precision digital micrometer Filetta, IP54 0–25/0.001 mm.The water content of the membranes was determined by the method of hot air drying [sw − mdry)/mdryW =  samples and samples swollen (sw) in the 0.02 M NaCl solution were found using the moisture analyzer, MB25 (Ohaus).The r drying  using thpH of the membrane internal solution was evaluated by the color indication method using the ability of anthocyanins to change their structure and color depending on the pH of the medium [–1) to various buffer solutions. The color of these solutions and the resin AV-17-2P, which has the same ion-exchange matrix and fixed groups as the studied membranes, was registered at constant luminous intensity (ensured by the constant electric power 14 W ± 5% consumed by the light source) and an optical path length of 225 mm. The resin underwent the prior salt treatment and was in contact with the studied 0.01 M NaCl or KHT solution, which contained the color indicator (2 mg L−1), for 48 h. AV-17-2P is a convenient object for the color indication method due to having sufficiently large pores that allow large indicator molecules to enter them. In addition, this resin has a pure white color in the air-dried state and when immersed in transparent solutions, i.e., it does not distort the colors of the indicator with additional shades, as it can happen with the studied membranes.The e medium . The colintegral coefficient of diffusion permeability (P) of the membranes was measured in a two-compartment flow cell. The scheme of the cell and the experimental technique are described in detail in [The etail in . Prior t2PO4 solution for 150 h, was equilibrated with the 0.05 M NaCl solution. The measurements were carried out in NaCl solutions at a temperature of 25 °C.In a separate experiment, the sample of MA-41, which was in contact with the 0.02 M NaHvolume fraction of the intergel spaces (f2) of the membranes was determined by treating the concentration dependences of membranes electrical conductivity in NaCl solutions [The olutions .Standard contact porosimetry was used to determine the integral volume of sorbed water per gram of dry membrane  or the number of water molecules per fixed group of AEM  as functions of the pore effective radius  and the binding energy of water . The method consists of measuring the equilibrium curve of the integral volume of sorbed water (or other liquid) of the test sample, which is sandwiched between two reference porous samples with a known pore distribution. Porosimetry curves for reference samples are obtained in independent experiments, for example, by using the mercury porosimetry method. A controlled change in the water content in the samples is carried out by evaporation into a closed volume. The fundamental details of this method are described in [ribed in ,54.wn) is determined by the equation:Q is the ion-exchange capacity of the dry membrane, mmol g–1dry.The number of moles of water per one mole of fixed groups of dry membrane (3 mol–1), −1 [The binding energy of water is calculated as follows:72 N m−1 ), and θ 3, NaH2PO4, and KHT for 150 h and then properly rinsed with deionized water. The rinsing was repeated until the electrical conductivity and pH of water equilibrated with the samples differed from those of initial deionized water by less than 5%.Prior to the experiments, the studied samples were immersed in 0.1 M solutions of NaCl, NaHCOP, of the studied membranes in solutions of NaCl, NaHCO3, NaH2PO4, and KHT. In the case of the heterogeneous membranes, the values of P in all the studied solutions turned out to be higher compared with the homogeneous membranes. Similar patterns were noted in many studies, e.g., [P values decreased with dilution of the external solution. In the case of NaHCO3, NaH2PO4, and KHT, on the contrary, a decrease in the salt concentration in the external solution almost always led to an increase in the diffusion permeability. Moreover, this increase intensified in the following sequence: NaHCO3 < NaH2PO4 < KHT.s, e.g., ,38. Diffs, e.g., ,55. AnotP* is determined by the diffusion permeability of the membrane gel phase, D, located in the intergel spaces.i in the gel phase and in the electrolyte are i has the values 1 (counterion) and A (co-ion). The gel phase, whose volume fraction in the membrane equals f1, is a microporous swollen medium. It includes the polymer matrix and the polar fixed groups attached to it, as well as the solution of mobile counterions and, to a lesser extent, co-ions, which compensate the charge of the fixed groups. The concentration of the electrolyte in the intergel spaces, which occupy the central parts of the mesopores, macropores, and various structural defects of the membrane and are filled with the electrically neutral solution, is equal to the concentration of the external solution. The volume fraction of intergel spaces in the membrane equals f2, f1+ f2= 1.The reasons for the increase in the diffusion permeability of the heterogeneous membranes as compared with the homogeneous membranes, as well as the decrease in the diffusion permeability of the membranes with the decrease in the concentration of strong electrolyte (NaCl) solutions are well known. In the framework of the microheterogeneous model ,19,56, tf2, the volume fraction of the solution, which is equivalent to the external solution, increases. Thus, the diffusion permeability of heterogeneous membranes, whose f2 is higher than that of homogeneous membranes Pstimates ,56,58,59stimates ,58 allowembranes , increasDK is the Donnan constant. This equation is deduced from the Donnan relation considering that the concentration of co-ions in the gel phase of the membrane is much lower than the ion-exchange capacity To assess the effect of the external solution concentration on the ion-exchange capacity of the membrane and the effect of charges of co-ions and counterions on the diffusion permeability of the membrane, it is convenient to use the following equation ,57:(5)cAAccording to Equation (5), for a given value of ar, NaCl .Another parameter that affects the diffusion permeability of the gel phase is the ratio If the values 3, NaH2PO4, and KHT. In the next section, we show that the internal solution of membranes immersed in NaHCO3, NaH2PO4, and KHT solutions is enriched with doubly charged counterions. The fraction of such ions in the membrane grows with dilution of the external solution; therefore, the number of co-ions in AEM rises, and Note, that in all the studied solutions, the electric charges of counterions and co-ions were the same and equaled to unity; however, diluting the external solution decreased the diffusion permeability of the membranes in the case of NaCl and increased the diffusion permeability in the case of NaHCO3, NaH2PO4, and KHT from NaCl is that these electrolytes contain acid anions that go into protonation/deprotonation chemical reactions with water. pK), as well as the distribution of molar fractions of the carbonic, phosphoric, and tartaric acid species depending on pH, which are calculated using these constants.The main difference of NaHCOf1 = 1). They were calculated considering the equilibrium constants of the protonation/deprotonation reactions of water (wK), the stepwise equilibrium constants (K1 and K2) for the corresponding acids, as well as the conditions of electroneutrality and ion-exchange equilibrium in the AEM and external solution. The pH values of external solutions corresponding to the maximum concentration of a singly charged anion were used for the calculations.The calculations are made in accordance with the following equations:Substituting Equations (11) and (12) into Equation (9) gives the following quadratic equation:The solution of Equation (13) is:Here,i and j counterions. A bar indicates the membrane phase. The presented equations consider the case of KHT. They are similar for the other electrolytes. The deduction of these equations is described in detail in [The etail in . The conc ≈ 1 M , 8.30 and 0.00 (NaHCO3), and 3.60 and 0.15 (KHT), respectively. At the same time, the pH and molar fraction values inside the AEM were 6.58 and 0.19 (NaH2PO4), 10.10 and 0.38 (NaHCO3), and 4.92 and 0.79 (KHT), respectively. Enrichment of the gel phase with doubly charged counterions led to an increase in the concentration of co-ions in it. Estimations in accordance with Equation (5) showed that the decrease in the concentrations of the external solutions from 0.01 to 0.001 M led to the decrease in the co-ion concentrations in the gel phase by a factor of 100 in the case of NaCl and only by a factor of 25 in the case of KHT. All other conditions being the same, the concentration of co-ions in the gel phase, which was in the form of a doubly charged ion, will be 10 times higher than in the case of singly charged anions. In this case, a 7-fold to 8-fold increase in the diffusion permeability of the gel phase can be expected.The calculations in accordance with Equations (9)–(14) demonstrated that the pH of the AEM internal solution was close to the pH of the external solution, when c ≈ 1 M . If 0.4 −3 mM lower than in the external solution. A small number of weakly basic fixed groups in AV-17-2P apparently caused such a slight difference in the pH in the case of NaCl.The calculation results were in good agreement with the data obtained from the color indication method . Indeed,42− < HCO32− << HT2−. This led to the fact that, when diluting the external solution, the co-ion concentration in the membrane gel phase decreased to a lesser extent than in the case of the strong electrolyte. The increase in the concentration of co-ions in the gel phase of the membrane increased its diffusion permeability. The higher the fraction of doubly charged ions in the gel phase of the membrane, the stronger the manifested effect.Thus, the pH of the internal solution of anion-exchange membranes (and resins) was higher than the pH of the external solution. Diluting the external solution increased these differences. At the same time, the AEM internal solution was enriched with doubly charged counterions, and the molar fraction of these ions at a given concentration of the external solution increased in the following sequence: HPOP in the range of dilute solutions were higher in the case of NaH2PO4 than in the case of NaHCO3, for which our theoretical estimates predicted a higher concentration of doubly charged counterions in the gel phase. The reason for the decrease in the diffusion permeability of the AEM in diluted NaHCO3 solution, apparently, was the alkalinity of the AEM internal solution , while the thickness of AMX-Sb increased by 7.6% (KHT) and 8.4% (NaH2PO4) relative to the NaCl solution. In the case of MA-41, which has the regularly crosslinked matrix, the value of the thickness stopped changing after about 50 h. In the case of AMX-Sb, which is composed of the randomly crosslinked polymer, the growth of the thickness did not stop during the entire observation period. Apparently, prolonged contact with strongly hydrated counterions leads to the rupture of some –C–C– bonds in the most weakly crosslinked parts of the matrix of this membrane. This causes an increase in the swelling of AMX-Sb and similar membranes up to their destruction, observed, for example, during prolonged electrodialysis of liquid media of the food industry, which contain highly hydrated substances [Electrostatic repulsive forces between neighbouring fixed groups contribute to the stretching of the elastic matrix and compensate for its liability to compress . Crosslibstances .More detailed information on the behavior of the membranes in solutions of different electrolytes was provided by the results of standard contact porosimetry and are presented in V–logr coordinates. The distribution of water over the ranges of the pore effective radii (ΔV) can be estimated from the difference of the values of V in the sections of the curve plateau that follow the inflection points. The total water content in the test sample (tV) was found by the difference in weight of a completely swollen and completely dry membrane. tV, in the studied samples, as well as the distribution of water in micro-, meso-, and macro-pores. These results were obtained by processing the curves presented in The effective radii of the pores that dominate the studied membranes were found from the values recorded at the inflection points of the curves presented in 3, NaH2PO4, or KHT solutions  increases when passing from NaCl to other studied electrolytes.According to the literature ,56, suchR3 = 1.7 ) and couwn in pores whose effective radii did not exceed 13 nm , 400 J mol−1 (NaHCO3), and 650 J mol−1 (NaH2PO4), i.e., the values of A increased in the sequence: NaCl < KHT < NaHCO3 < NaH2PO4. It can be assumed that the amount of bound water in micro- and meso-pores, whose presence contributes to the stretching of the ion-exchange matrix of membranes, also increased in the same sequence. This sequence was very similar to the sequence of the Gibbs hydration energy growth: 3 solution was less than expected due to the phenomenon already discussed in 2PO4 solutions, in which the gel phase have acidic or close to neutral pH values.A comparison of binding energies of water at a given GCO32−0, , though The fact that, in all the examined ranges of the pore size, the water content (expressed as a percentage) was a little dependent on the type of electrolyte  allows c3, KHT, and NaH2PO4 solutions indeed leads to an increase in bound water in micro- and meso-pores. Therefore, the contact of AEM with anions of carbonic, phosphoric, and tartaric acids causes the stretching of the ion-exchange matrix. Since doubly charged ions are more hydrated than singly charged ions, the degree of stretching of the ion-exchange matrix and pore size should increase with dilution of the external solution because the proportion of doubly charged counterions increases with dilution of the external solution (see f2). Apparently, the swelling process leads to a decrease in adhesion between the ion-exchange material, the inert binder, and the reinforcing cloth of MA-41. As a result, the macropores size of this membrane grows and volume fraction of the intergel spaces, f2, grows more than in the case of the studied homogeneous membranes.Thus, substituting a NaCl solution with NaHCOtion see . The conf2, of the AMX-Sb and MA-41 membranes that were immersed in NaH2PO4 and KHT solutions for 150 h increased by about 20 and 30%, respectively, compared with f2 of AEMs that were immersed only in the NaCl solution , this increase in  of NaCl .3; monosodium phosphate, NaH2PO4; and potassium hydrogen tartrate, KHT) and a strong electrolyte .The analysis of concentration dependencies of diffusion permeability of homogeneous (AMX-Sb and AX) and heterogeneous (MA-41 and FTAM-EDI) anion-exchange membranes (AEMs) was carried out in solutions of ampholytes  the enrichment of the internal solution of AEM with multiply charged counterions and (2) the increase in the pore size of AEM.When diluting ampholyte solutions, the diffusion permeability of the membranes, on the contrary, increased, despite the fact that the concentration of co-ions decreased with dilution of the external solution. This increase intensified in the sequence: NaHCOThe enrichment of the internal solution of AEMs with multiply charged counterions was caused by the Donnan exclusion of protons, which are the products of protolysis reactions. The results of the calculations and experiments showed that the pH of the internal solution of the AEMs was higher than the pH of the external solution. This difference increased with dilution of the external solution. At the same time, diluting the external solution resulted in enriching the internal solution of AEM with doubly charged counterions. This led to the fact that, with dilution of the external solution, the concentration of co-ions in the gel phase of the membrane decreased to a lesser extent than in the case of the strong electrolyte.The measured membrane thicknesses, standard contact porosimetry data, as well as the obtained values of the volume fraction of the AEM intergel spaces allowed to conclude that the penetration of strongly hydrated anions of carbonic, phosphoric, and tartaric acids into the AEMs led to the stretching of the ion-exchange matrix in all the studied membranes.


The purpose of this study is to scrutiny the Dynamics of heart rate variability (HRV) in patients with PICS with 2nd type DM against the background of Taurine (TN) and meldonium (ME). The results of the investigations prove the decrease of the oxidative stress, which is basis of DACN, under the influence of sulfur-containing amino acid taurine (TN), and meldonium (ME) — a competitive inhibitor of gamma-butyrobetaine hydroxylase. Biochemical mechanisms of synergistic action of ME and TN are also described. The results of the studies of 98 patients with PICS and concomitant 2nd type diabetes mellitus were analyzed. They were distributed by simple randomization method into two groups, comparable according to age and sex: the main group (MG) (n = 68): and group of comparison (GoC) (n = 30). HRV was evaluated twice daily at the Cardiosense HMEGG system: at baseline and after 12 weeks of treatment. For the assessment of HRV the frequency and spectral parameters were used. While evaluating the different methods of treatment, their influence on the range of spectral and time indices of HRV was determined . It was learned that the combined application of ME and TN gives a statistically significant (p <0.01) increase of SDNN, HF at night, pNN — on 50% by day , and statistically significant decrease in LF at night, compared to GHG. Low heart rate variability (HRV) as a manifestation of diabetic autonomic cardiac neuropathy (DACN) has a high correlation with the risk of sudden coronary death. –4. SympaAll antiarrhythmic drugs classified by Voughan-Williams have a number of side effects and contraindications, and a significant amount is characterized by a proarrhythmogenic effect –18.A promising direction may be the use of drugs that affect the energy metabolism of the myocardium (M).Ability of metabolic therapy (MT) to increase the stability of the nervous system (NS) to adverse factors of different origin, activate plastic processes in the central nervous system (CNS), normalize the energy status of nerve cells is proven. In addition, the peculiar feature of MT is the practical absence of complications and side effects and the possibility of their combination with other drugs.Important predictors of endogenous response to the treatment are amino acids (AMAs). –24. The TN is a sulfur-containing amino acid, which remains in free form, unlike other amino acids that can be used as substrates for the formation of other proteins. It is proved that TH is one of the main regulatory substances that restore the neurodynamic and sympathetic-parasympathetic balance (SPB). ,26. In tME is a competitive inhibitor of gamma-butyrobateine hydroxylase, which inhibits intracellular synthesis of carnitine. The latter is responsible for the transport of fatty acids (FA) through the membrane of mitochondrias. The results of the investigations confirm the tonic effect of ME on the CNS and the vividly expressed antiarrhythmic activity –32.It was proved that inhibition of the stearoyl-CoA desaturase enzyme (SCD-1) suppresses oxidation of the FAs and increases the tissue’s sensitivity to insulin. And this very enzyme is a connecting link between AMAs and FA. Expression of this enzyme is proved in the relation to TN. The synergistic effect of ME and TN can be explained by above mentioned Biochemical interactions .Consequently, the multiple use of ME and TN in patients with PICS and 2nd type diabetes is not described in previous studies, but a significant amount of such the data on their isolated effects on HRV and mutual action potentiation has been accumulated.Purpose: to learn the Dynamics of HRV indices in patients with PICS and 2nd type DM against the background of the use of taurine (TN) and meldonium (ME).The results of a survey of 98 patients with PICS and concomitant 2nd type DM were analyzed, which were distributed by simple method of randomization into two groups: main group (MG), (n = 68): 36 women and 32 men, median age of patients — 65.5 years (IQR (interquartile range) — 61-68 years), and the group of comparison (GH) (n = 30): 17 women and 13 men, median age - 64.7 years (IQR — 64-68 years). The investigations involved patients with PICS and associated 2nd type DM who were informed and agreed to the experiment. The control group (CG) was represented by 30 persons, age and gender were in comparison with PICS and 2nd type DM patients.Criteria for exclusion from the study: chronic heart failure IIB-III stage according to Strazhesko-Vasilenko classification, acute coronary syndrome during the last 12 months, congenital and acquired heart defects, complete blockade of LBBB, implanted pacemaker, AV-blocks II-III of II-III stage, atrial fibrillation, autoimmune diseases, malignant oncological diseases, expressed renal, hepatic, respiratory failures, endocrine diseases (except 2nd type DM).The general clinical characteristics of patients is shown in the Patients from main group received basic treatment (BT), which included an ACE inhibitor, beta-adrenoblocker, statin, antiaggregant, oral hypoglycemic therapy, and additionally 1 capsule 500 mg 2 times per day of ME and additionally 1 capsule 400 mg of ME 3 times per day and 1 capsule 400 mg of TN. 3 times per day. Patients from GoC received only BT PICS and 2nd type DM drugs. In order to study the complex and isolated effects of TN and ME on the frequency of ADR, MG was divided into 3 subgroups according to the additional BT treatment BT. The 1st subgroup (GoC 1st) included 22 patients, who received TN, 2nd subgroup (GoC 2nd) — 23 patients, receiving ME, 3rd subgroup (GH 3) — 23 patients, who received combined ME and TN in addition to BT.HRV was evaluated twice daily at the Cardiosense HMEGG system: at baseline and after 12 weeks of treatment. For the assessment of HRV was used the frequency and spectral parameters. We studied the following frequency characteristics of HRV: SDNN(MS) – standard deviation of all intervals R-R; RMSSD (MS) – the square root of the mean sum of squares of differences between adjacent intervals R-R; pNN50 (%)- the number of pairs of neighboring intervals R-R ,which differ more than 50 MS in the entire recording. Among the following spectral indices: TP – Total power (MS2) total power of HRV spectrum, LF (MS2) – slow wave (low frequency) part of the spectrum in the frequency range from 0.04 to 0.15 Hz, VLF (MS2) very low frequency part of the spectrum in the range of 0.0033–0.04 Hz, VLF (MS2) very low frequency part of the spectrum in the range of 0.0033-0.04 Hz, UVLF (MS2) ultra low frequency component with the frequency of the wave to 0.0033 Hz, HF (MS2) – high frequency component in the frequency range from 0.15 to 0.5 Hz, the ratio LF/HF sympatho-wagusnye of balance. Used software allowed to carry out a dynamic assessment of frequency and spectral indices of HRV in the daytime and during sleep. In order to exclude the influence of defects of record, artifacts, noise in the analysis of HRV parameters was carried out a thorough analysis of all the unidentified QRS complexes and artifacts. In measuring and evaluating the results of the ECG EC, the recommendations of the Task Force of the European Society of Cardiology and the North American Society of Cardiac Stimulation and Electrophysiology were followed . StatistThus, according to the HRV analysis, there was a significant decrease of one of the most sensitive indicators of HRV-SDNN compared with CG patients with PICS and 2nd type DM (p <0.05). The latter characterizes the total effect of vegetative regulation of blood circulation. At the same time, it was monitored a significant (p <0.05) decrease in RMSSD compared to GOC in patients with PICS and DM, indicating a decrease in the activity of the parasympathetic nervous system (PNS).Relative (p <0.05) decrease in mRR in patients shows a relative increase in the effects of the sympathetic nervous system (SNA) during the day. This is also confirmed by the probable (p <0.05) decrease in the circadian index in these patients compared with GOC patients. Rigidity of HRV appeared in a peculiar way in patients with PICS and DM 2 as a result of weakening of vagal influences. The latter fact indicates the presence of autonomic myocardial denervation .While the spectral analysis of HRV conducting, a significant decrease in the total spectral power  was found in patients with PICS with concomitant 2nd type DM, as compared with those of GOC patients. It is characterized by a decrease in ТР in the daytime due mainly to very slow  and slow  waves, which determine the activity of the SNA and humoral and metabolic effects. At night, changes in ТР were due to a decrease in power and fast waves , which characterizes the activity of PNS. The growth of the LF / HF index in the examined patients compared with the GOC patients indicates a relative prevalence of the SNA in patients with PICS and 2nd type DM. It can be the result of a decrease in the sensitivity of the sinus node to the nerve regulation due to the steady activation of the SNA.In the study of the effectiveness of the multiple treatment of ME and TN, a significant (p <0.01) increase in SDNN was observed against the background of the use of ME and TN in the night period in all subgroups of MG, especially expressed in SG3. At the beginning of investigations, before the appointment of ME and TN, all subgroups of MG and GOC were comparable according to the values of time and spectral indices of the HVR (STI HRV). Thus, the multiple treatment of ME and TH contributed to reducing the tension in the functioning of the SNA. Normalization of RMSSD was noted, and pNN increase on 50% by day. The most vivid in comparison with the initial stage of the study was the change in SG 3.While analyzing the spectral indices of HRV, it was learned that the multiple treatment of ME and TH contributed to the decrease of VI. These results were reflected in a significant (p <0.01) decrease of LF and increase of HF at night, vividly expressed in patients with SG3 .While evaluating the different methods of treatment, their effect on the STI HRV indices was proved . It was found that the multiple treatment of ME and TN gives statistically significantly higher growth of SDNN, HF at night, pNN – on 50% by day , and a statistically significant decrease in LF at night, compared with SG.Statistically significant differences in growth of SDNN, HF at night, pNN – on 50% in the afternoon and LF decrease in night PG1 and PG2 between themselves and with GOC were not detected (p> 0.05).The violation of autonomic regulation of cardiac activity in patients with PICS and 2nd type DM is characterized by vegetative imbalance and weakening of humoral, metabolic and vagal influences, relative sympathysation, decreased PNS activity. While evaluating the influence of various methods of treatment on the value of STI HRV It was learned, that the multiple treatment of TN and ME in addition to BT during 12 weeks in patients with PICS and 2nd type DM positively affects the STI HRV and also normalizes the vegetative balance by reducing the tension in the functioning of the SNA and activating parasympathetic rhythm regulation. Statistically significant differences STI HRV changes while comparing separate 12-week appointment of ME in addition to BT and a separate appointment of TN in addition to BT within 12 weeks, with each other and with BT treatment was not detected (p> 0.05).The authors confirm that there are no conflicts of interest


The data provided in this article supplements the data information provided in “Techno-economic analysis of electricity and heat production by co-gasification of coal, biomass and waste tyre in South Africa” [1]. The generation of the data considered co-generation of a coal sample  with pine sawdust, sugarcane bagasse, corn cob, and waste tyre at a blend ratio of 1:1, 3:2, and 4:1. The cost evaluation of the use of the feedstocks was considered with feedstock costing (WFC) and without feedstock costing (WOFC). Profitability assessment tools for the case study included NPV, IRR and PBP. The data as contained in this article could be useful for a quick decision making on a similar project by the government and stakeholders in the sector. Specifications tableValue of the data•2 emission in the country is the highest in the whole of Africa. In this regard, the use of this data article could be instrumental to the reduction in the rapid depletion of the coal reserve, and emissions.South African coal reserve depletes very fast, and the CO•As for as could be ascertained, data describing the electrical and thermal power production in a 5 MW CHP plant using South African feedstock is not available in the open literature; thus, a set of data provided in this article, could be used as a platform for decision making and further R&D in this area.•With the provided dataset, investors can have a good understanding of the techno-economic analysis of the power generation in the plant before embarking on the investment, meaning that the dataset provides a working guide for interested investors.•Policy-making in energy, economic and environmental sectors could consider the dataset, for the modification of existing policies.1The dataset provided in this article supplements the data information provided in 2South African feedstocks comprising coal and solid waste  were pre-treated by milling and sieving and kept in air-tight bags for analysis. Characterization of the feedstocks was carried out using CHNS-O Organic Elemental Analyzer (FLASH 2000), TGA-SDT (600), Oxygen-bomb calorimeter 203 M 1241) for the ultimate, and proximate analysis and heating value determinations, respectively, and using coal-to-solid waste ratios of 1:1, 3:2, and 4:1. The result from characterization analysis was used in the empirical model Eq. ) to obta M 1241 fFig. 2The economic evaluation of electricity and thermal power generation from the plant was then carried out using the net present value (NPV), internal rate of return (IRR), and payback period (PBP) as the project tools at 10th, 11th, 17th and 18th investment years based on two financial situations namely: with feedstock costing (WFC) and without feedstock costing (WOFC). The appraisal tools and emission models used are provided in Eqs. [5]SD is the standard deviation of the sensitivity analysis variables;


The thicknesses of WO3 (around 50~60 nm) and Ag (10~20 nm) films were mainly the changeable factors to achieve the optimal transparent conductivity attempting to replace the indium tin oxide (ITO) in cost consideration. The prepared films were cardinally subjected to physical and electrical characteristic analyses by means of X-ray diffraction analysis (XRD), field-emission scanning electron microscope (FE-SEM), and Keithley 4200 semiconductor parameter analyzer. The experimental results show as the thickness of the Ag layer increases from 10 nm to 20 nm, the resistance becomes smaller. While the thickness of the WO3 layer increases from 50 nm to 60 nm, its electrical resistance becomes larger.In this work, three layers of transparent conductive films of WO The transparent conductive film (TCF) offers versatile and cost-effective applications with a light transmittance of 80% or more in visible light range (400 to 800 nm) and low resistivity , sometim2O3). Furthermore, it is inferred that the conductivity of this film is a crystal defect derived from the film structure itself. In 1968, Philip found that the doping of Sn ions in the indium oxide film enhanced the conductivity of the overall film, and then produced In2O3:Sn film [Most of metal thin films such as Au, Ag, Cu, Pt, and Al are, basically, good infrared reflectors. If the optical transparency in the tunable region is strongly enhanced, the preferred thickness of the metal film layer is less than 10–20 nm. Theoretically, the metal thin film can be treated as a good transparent conductive film, but when the thickness of the metal thin film is less than 10 nm, it is easy to form discontinuous island-like films, so that the resistivity of the thin film increases and the scattering incidence light in turn reduces the transparency of the film itself [:Sn film , now wid3 according to the present experiment is usually an n-type semiconductor material and has a work function (Φs) around 5.7 V.The transparent conductive oxide of the metal is transparent in the visible region. For electrical properties, these oxides are usually doped with some metal impurities, doped with metal ions that are more than one cation of the original compound to form an n-type semiconductor, or doped with a non-metal ions less than its anion to form a p-type semiconductor. It is also probable to generate a compound having an incomplete oxidation state, so that an anion void is contained in the material, and WO3), a semiconductor material with a large energy gap, it has a chance to form a transparent conductive film mainly composed of tungsten oxide and a silver metal layer in the middle. According to different characteristics of the WO3/Ag/WO3 transparent conductive film, it is expected to develop different application components and products in the future. Tungsten oxide (WO3) generally proposes a molecular weight of 231.838 g/mol, a density of 7.2 g/cm3, and a melting point of about 1473 °C and is soluble in water and ammonia, but slightly soluble in hydrofluoric acid, and, however, insoluble in acid. Tungsten compounds can usually exhibit five different ionization states, W2+, W3+, W4+, W5+, and W6+. There are also cases where codons of different valences coexist. WO3 is the highest valence oxide of tungsten. As usual, the oxygen content in tungsten oxide does not exactly meet the full stoichiometric ratio of O:W = 3:1, so that the chemical formula is often expressed as WO3−x. The conductive mechanism of the tungsten oxide is chiefly via oxygen vacancies. Oxygen vacancies are mainly formed because of the large number of tungsten oxides arranged, and the oxygen atoms in the structure are vacant due to defects in the material itself. In this case, the chemical formula of tungsten oxide should be WO3−x, and the sporadic oxygen vacancies will generate a new energy level below the conduction band. At the generated energy level, the active electrons are able to be transited to the upper energy levels. The conduction band generates free electrons and is thus electrically conductive [Among many metal materials, silver (Ag) material is a good choice in conductivity and relatively good photoelectric characteristics. Accompanying tungsten oxide  orbital, the conduction band is localized in the t2g orbital of the central metal W6+, and the Fermi level is between the O(2p) band and the W(t2g) band [2. The Fermi level (EF) of WO2 is generally in the conduction band, so that active electrons do not need much energy to look for the quantum state of the vacancy for jumping and inducing current conduction. The bandgap of WO2 is not remarkably observed.As shown in 2g) band ,12,13,14The chosen substrate in this work is a glass substrate, which is a level of sodium glass. The selected target of tungsten is a 2-inch circle type with the integrity 4N. In the experiment, the flowing gases are pure argon and oxygen. Before the sputtering, the glass substrate must be cleaned well with acetone, de-ionized (DI) water, and alcohol in the operation of ultra-sonic equipment. After that, the de-dry process with nitrogen is subsequently executed. Before the beginning of sputtering, the glass substrate required for the experiment must be cleaned, placed in a beaker containing acetone, deionized water, and alcohol, and then in an ultrasonic oscillator for 10 min. The function of acetone is to remove the organic matters on the surface of the substrate. Deionized water can take out the dust and chemicals on the substrate surface. Alcohol takes the surface moisture of the substrate away. After cleaning, the residual alcohol on the surface of the glass substrate should be fully dried out by a nitrogen gun.–5 torr for tungsten oxide deposition the gas introduced into the chamber was argon (flow rate: 30 sccm) and oxygen (flow rate: 24 sccm), and the working pressure was 7 × 10–3 torr. For deposition of a silver layer, the gas was argon (flow rate: 30 sccm), and the working pressure was 6 × 10–3 torr, and the tunable rotation speed was set to 300 rpm. Subsequently, the metal target must be pre-sputtered for 15 min before the start of sputtering to remove impurities from the target surface. After the plasma environment stabilized, the baffle between the target and the stage was slowly removed, and the procedure of film deposition was begun. Continuously, after the sputtering completed, the test piece was taken out. Ultimately, the plating analysis and the property test for the deposited films were performed. During the sputtering process, the thicknesses of the silver (10 or 20 nm) and the tungsten oxide (50 or 60 nm) and the RF power to generate the plasma were the main changeable factors, as shown in 3/Ag/WO3 film, as shown in 3 film is represented in 2 is in the range from 4.41 to 4.6 V.After the cleaned substrate was placed in the sputtering chamber, the magnetron sputtering system was step by step turned on for sputtering, following the standard operation procedures, and the mechanical pump was used to pump the chamber. When the pressure of the chamber reached 0.05 torr, the diffusion pump was added and pumped up to the background pressure of 2 × 10In order to probe how adding electrodes influences the electrical characteristics of WAW films, the metal electrodes providing the different work functions, as shown in In the measurement results, we discuss the electrical and physical performance of the WAW film stack. The optical transparency of the WAW film at wavelength = 550 nm is slightly investigated.3 with 50-nm thickness was deposited. Then, the silver (Ag) layer was sputtered up to 10 nm. During this time, the surface of this Ag film demonstrated fine black holes, which means that the Ag film was not sufficiently thick to form a continuous film. Nevertheless, as the thickness of the silver was increased up to 20 nm, the pores completely disappeared and the silver film became uniform, as shown in First of all, the bottom WO3/Ag/WO3 (WAW) sample was coated without a sacrificial layer W before sputtering the upper layer of tungsten oxide, the Ag film was easily oxidized as silver oxidation (AgO) decreasing the conductivity, which is not desired in applications. To prevent Ag film from the oxidation depicted in As WO3 (50 nm) and Ag (10 nm) films were measured separately. It can be found that the diffraction peak of tungsten oxide was not observed in 3 film formed by sputtering with the W target during sputtering, to verify whether there was oxidative unevenness, three XRD points at different locations were measured. The XRD characteristics expressed the same, and all of them were amorphous structures. In In the XRD pattern analysis, the WOThe quality of Ag films on glass substrate, besides the observation with SEM photos in the material view, also can be evaluated with I–V characteristics, as shown in 3 film is tremendously improved, as shown in If the WAW film is deposited with a metal electrode such as gold metal, the voltage drop at the starting voltage for a single WO3 layer treated as an anti-reflective layer was deposited with 50 nm thickness, the transmittance in WA(10)W could be increased. If there were only two layers, bottom WO3 with fixed 50 nm thickness and silver layer, the thickness of the silver layer was increased and the transmittance performance was reduced. Reversely, the conductivity of the silver layer was increased according to the previous analysis. Using the wavelength = 550 nm as an example, the transmittance with the variables of silver thickness is represented at According to the UV-Vis spectrum of WA films, as shown in 3 thicknesses as an anti-reflective layer is also important for the transparent conductive film. Following the previous section, the manufacturing process for the bottom WO3 (W(50)) and silver layers (A(10)) was identical, but the thicknesses of the top WO3 layer were changeable. The measurement results with UV-Vis spectrum are shown in Understanding the transmittance versus the top WOTransparent conductive films (TCF)  have a wFollowing the analysis of XRD results and SEM images to examine the crystallinity of silver film or tungsten oxide can provide a suitable growth thickness of the silver layer or tungsten oxide. With the electrical measurement and optical spectrum scanned, the optimal sputtering parameters in thickness control of the top and bottom of the tungsten oxide and silver layer can be wholly extracted and confirmed. The tunable thickness of the top tungsten oxide as an anti-reflective layer is intensely related to the transmittance. Summarizing these sensed consequences, the optimal thicknesses of WAW film should be W(50)/A(20)/W(50) in this experiment.In this work, a thin barrier layer of tungsten on the silver film was necessarily deposited to prevent this film from oxidation and keep great conductivity for the full WAW film. In the electrical measurement, if the metal electrode is deposited, the probe resistance between the tungsten oxide and probe needle can be diminished more and the parasitic resistance confusing the measurement error also declined.