Matrix Fragments Research Articles

Specific Features of the Structure of Various Coal Ranks at the Nano Level

Structural factors and functions of radial distribution of atoms of different coal ranks have been calculated by X-ray diffraction analysis. This made it possible to establish that the main structural component is the clusters with graphite-like packing of atoms. The predominant size of these clusters (calculated from the peaks of small-angle X-ray scattering at 5° in CoKα-radiation) for coals with a carbon content of 83--95 % is within 2--3 nm. Fossil coal is an amorphous carbonaceous substance consisting of polymorphic modifications in the sp2- and sp3-states. According to the results obtained using Raman scattering spectroscopy, the physical properties of amorphous natural coals are strongly dependent on the ratio of sp2- and sp3-hybridization of atomic orbitals. Moreover, studies have shown that the carbon atoms of the coal matrix in the sp2-state are represented by both aromatic and aliphatic conjugated chain fragments. It was found that the degree of ordering in rank LF coals is higher than in coals of a higher stage of metamorphism. This is possible if the hydrocarbon matrix in rank LF coals can be represented as a polymer consisting of conjugated chains with periodicity. With an increase in the stage of coal metamorphism, starting with coal rank G, the transformation of the coal structure occurs with a violation of the periodicity of the conjugated fragments of the polymer matrix connecting graphite-like clusters, a decrease in their length, and an increase in randomness in their arrangement

A condensation origin for the mass-dependent silicon isotopic variations in Allende components: implications for complementarity

Primitive chondrites have bulk compositions close to that of the solar photosphere, with however significant variations of elemental ratio relative to the solar composition, depending on the volatility of the elements considered. This is classically understood as indicating a primary geochemical signature due to the formation of the components of chondrites (refractory inclusions, chondrules and matrix), or of their precursors, through condensation of a gas of near solar composition, plus secondary variations due to processes such as (i) incomplete volatilization of presolar components, (ii) complex high-temperature exchanges between condensed phases and the nebular gas, and (iii) sorting and transport of grains in the accretion disk before accretion of chondrite parent bodies. Because most of the mass of chondrites is made by elements which condense at high temperatures, equilibrium condensation produces in general little isotopic fractionation for these elements. Silicon is however an exception with per mil level equilibrium isotopic fractionation at high temperature between the SiO gas and condensed silicates, allowing to use silicon isotopes in chondrites to constrain the origin of their components and to put at test scenarios of condensation.Individual components (chondrule fragments, isolated olivines in the matrix, and matrix fragments) of the carbonaceous chondrite Allende were separated and analysed at high-precision for their silicon isotopic composition. Large variations have been found among chondrules (δ30Si from -0.86 ± 0.16‰ 2 s.e. to +0.04 ± 0.03‰ for 11 chondrules), isolated olivines (δ30Si from -0.51 ± 0.12‰ 2 s.e. to +0.20 ± 0.10 ‰ for 12 olivines), and matrix (δ30Si from -0.95 ± 0.08‰ 2 s.e. to -0.41 ± 0.01 ‰ for 17 matrix fragments). These variations distribute on both sides of the bulk δ30Si value of Allende (-0.43 ± 0.03‰ 2 s.e., Armytage et al., 2011; Pringle et al., 2013, 2014; Savage and Moynier, 2013). There is a global positive trend between δ30Si values and Mg/Fe ratio for chondrules and isolated olivines. This systematics appears in agreement with what can be modeled for producing Allende components, or their precursors, from fractionated condensation of a single gaseous reservoir having initially the silicon isotopic composition of bulk Allende. Mass balance taking into account the mean abundances and δ30Si values of Allende components is consistent with their accretion in the Allende parent body in the proportions produced by the condensation of the parent parcel of nebular gas. This supports complementarity between chondrules, olivines and matrix as being a primary feature. However, this conclusion cannot be definitive because of the uncertainties in defining mean δ30Si values for Allende components.

Strong genetic differentiation on a small geographic scale in the Neotropical rainforest understory tree Paypayrola blanchetiana (Violaceae)

Self-incompatible plants as well as common plant species are expected to be especially vulnerable to the deleterious effects of fragmentation on genetic diversity. Paypayrola blanchetiana (Violaceae) is a common, self-incompatible understory tree in the East Brazilian Atlantic forest. Its autochorous seed dispersal and occurrence in dense, well-separated clusters makes it an interesting model for studies of gene flow and genetic structuring on a small geographic scale. A previous study has found remarkably low fruit set and frequent seed abortions in this species in several populations situated in forest fragments. We tested the hypothesis that P. blanchetiana is affected by inbreeding and loss of genetic diversity in a fragmented landscape. Nine nuclear and three plastid microsatellite loci were genotyped for 285 individuals (149 adult trees and 136 saplings) across seven populations in five forest fragments in a 240-km2 sugarcane-rainforest matrix. We found a low to moderate genetic diversity in nuclear loci of P. blanchetiana, population structuring on a small geographical scale and high levels of inbreeding. Haplotype distributions confirmed that seed dispersal is very limited. There were, however, no signs for lower genetic diversity or higher inbreeding in populations situated in the smallest forest fragments. Furthermore, genetic diversity was not lower in the sapling cohort, which was created in post-fragmentation condition. Therefore, we may be witnessing the genetic consequences of this species’ biology, rather than immediate effects of fragmentation.

Modeling of light propagation in a wood polymer-sand composite

The subject of the research is wood polymer-sand composite (WPSC) and study of its physical and mechanical properties. In this case it is propagation of light in the material using simulation and development of a computer program to simulate the propagation of UV radiation in WPSC block. A separate computer program in the Object Pascal language was compiled to study the model. The program is designed to simulate two-dimensional approximation of infrared, visible, ultraviolet radiation propagation in wood polymer-sand composite. The program is applicable in a wide range of concentrations of the composite components, for different optical absorption coefficients of the components, depending on the wavelength of the radiation. Concentrations, optical properties of the components, and lighting conditions can be specified in the text of the program. The results of the program are the structure of the composite as a random uniform distribution of wood and sand fragments in a polymer matrix, a cartogram and a graph of the intensity distribution in the composite specimen. The result has been obtained: penetration depth of destructive UV radiation is about 1.5 mm at an optimal concentration of the components CW=45%, CPI=35%, CSa = 20%.

Use of bioactive extracellular matrix fragments as a urethral bulking agent to treat stress urinary incontinence

Injection of urethral bulking agents is a low-risk, minimally invasive surgical procedure to treat stress urinary incontinence (SUI). In this study, we developed a promising injectable bulking agent comprising extracellular matrix fragments of adipose-derived stem cell sheets (ADSC ECM) and investigated its effectiveness in urethral bulking therapy. The structural integrity and proteins of ADSC sheet ECM were well retained in decellularized ADSC ECM fragments. To locate transplanted ADSC ECM fragments, they were labeled with ultrasmall super-paramagnetic iron oxide nanoparticles, which enabled in vivo monitoring after implantation in a SUI rat model for up to 4 weeks. When ADSC ECM fragments were injected into the rat urethra, they became fully integrated with the surrounding tissue within 1 week. Four weeks after transplantation, host cells had regenerated within the ADSC ECM fragment injection area. Moreover, new smooth muscle tissue had formed around the ADSC ECM fragments, as confirmed by positive staining of myosin. These results indicate that injection of ECM fragments may be a promising minimally invasive approach for treating SUI.

Urban divide: predictors of bird communities in forest fragments and the surrounding urban matrix

ABSTRACT Over 50% of the world’s human population lives in cities, and the rate of urbanisation continues to increase globally. Consequences of urbanisation, such as noise pollution and land use change, impact bird communities and movement dynamics. Furthermore, cities are fragmented and heterogeneous, so it is pertinent to assess how birds respond to urbanisation at different scales. We quantified avian community composition in relation to environmental variables at 1) a city scale across an urbanisation gradient, and 2) a smaller spatial scale, within urban forest fragments. In the gradient study, species richness was highest in the peri-urban zone and declined with urbanisation. Bird density peaked at a moderate level of urbanisation, with medium housing density. Native species were more likely to be recorded where there were more shrubs and trees, less noise pollution and fewer impermeable surfaces. Within urban forest fragments, bird communities were less likely to be dominated by a few introduced species, and had high native species richness relative to counts in the urban matrix. Increased native bird richness and abundance within fragments were primarily associated with less noise and lower neighbouring human density. Differences in bird composition between the urban matrix and urban fragments suggest the matrix can be improved to facilitate the dominance of native bird species by reducing noise and adding vegetation. Understanding how birds use urban environments not only allows us to measure changes as a result of urban intensification but also allows for management of cities to improve the status of urban bird communities.

Home range of the mouse Phyllotis osilae in forest fragments of Polylepis subtusalbida with different habitat matrix

Home range is an aspect of ecology that allows us to understand the mechanisms and spatial relationships that underlie habitat choice and animal responses to environmental change. However, studies on this subject have been focused mainly on medium and large mammals, while those on small mammals are scarce. Small mammals play important roles in maintaining ecological processes, such as the survival of several plant species. Phyllotis osilae is a phyllotine rodent, which functions as a potential seed disperser for Polylepis subtusalbida , a tree that is endemic and categorized as Vulnerable (VU) for Bolivia. The forests of P. subtusalbida are highly fragmented, with reforestation with introduced species such as Pinus radiata and Eucalyptus globulus . The question we pose for this study is: how does the home range of P. osilae vary between fragments of P. subtusalbida with different types of matrix (natural grassland and exotic tree plantations)? The study was carried out on four fragments of P. subtusalbida in Tunari National Park in the city of Cochabamba, Bolivia: two fragments in the exotic tree plantation matrix (Pajcha locality) and two in the natural grassland matrix (San Miguel locality). For telemetry purposes, radio collars were installed on 16 individuals. The home ranges were calculated using the Minimun Convex Polygon (MCP) at 95 %, in the same way the Kernel density (KDE) was estimated at 95 %. The percentage of presence of P. subtusalbida and matrix trees within each home range was determined, with an area interval between 50.5 m 2 and 3,010 m 2 . No significant differences were found between both matrices regard to the area of activity; however, in the comparison of the percentages of presence of P. subtusalbida trees and matrix, significant differences were found. Our results for home ranges show that the matrix would not have an effect on the area, but on its mobility; this is evidenced by the absence of movements of P. osilae from the fragments to the exotic matrix. In this case, the exotic tree matrix is operating as a barrier and is reflected in the almost total absence of this vegetation matrix in the home range. P. osilae may be playing an important role in the recovery and conservation of these ecosystems, so knowing aspects of their natural history as well as their responses to fragmentation is of great importance in understanding the fate of the Polylepis forests.

Luminescent Properties of Mixed-Ligand Neodymium β-Diketonates Obtained in Supercritical Carbon Dioxide in Polymer Matrices of Various Nature

Diverse-ligand phosphor complexes of neodymium acetylacetonate with phenanthroline have been synthesized in polymer matrices (oligourethanmethacrylate, fluoroplast, and polycarbonate) in the medium of supercritical carbon dioxide, while the role of one of the ligands in such complexes is performed by the polymer matrix fragments. The luminescence spectra of the obtained triple systems have been described and it has been shown that the position of the luminescence maxima is bathochromically shifted relative to the Nd(Acac)3/polymer double systems obtained in a similar way and the shift magnitude depends on the polymer matrix nature. It has been shown that when these components are introduced into polymers from a solution, such phosphor diverse-ligand neodymium complexes are not formed. The formation of new Nd(Acac)3/1,10-phenanthroline/polymer structures at the impregnation of oligourethane methacrylate by neodymium β-diketonate and phenanthroline in the supercritical CO2, which are not formed by the introduction of these components from solution, has been confirmed by differential thermal analysis.

On the formation of ridges and burnished debris along internal fatigue crack propagation in 42CrMo4 steel

AbstractA detailed microscopic analysis of fracture surfaces of 42CrMo4‐hardened steel after ultrasonic fatigue testing revealed globular and cylindrical particles located in ridges along the crack propagation direction. Observed particles could be easily taken for non‐metallic inclusions; however, chemical analysis showed that they are of the same composition as the steel matrix. The formation of such round‐shaped debris was found to be a result of cutting out the matrix fragments by ‘en passant’ cracks interaction and their subsequent fretting burnishing. Possible correlation of the parameters of ridges and debris with cyclic plastic zone width and martensite structure is discussed.

Combining surface-sensitive microscopies for analysis of biological tissues after neural device implantation.

In order to address the complexity of chemical analysis of biological systems, time-of-flight secondary ion mass spectrometry (ToF-SIMS), x-ray photoelectron spectroscopy (XPS), and x-ray photoemission electron microscopy (XPEEM) were used for combined surface imaging of a biological tissue formed around a surface neural device after implantation on a nonhuman primate brain. Results show patterns on biological tissue based on extracellular matrix (ECM) and phospholipid membrane (PM) molecular fragments, which were contrasted through principal component analysis of ToF-SIMS negative spectrum. This chemical differentiation may indicate severe inflammation on tissue with an early case of necrosis. Quantification of the elemental composition and the chemical bonding states on both ECM-rich and PM-rich features was possible through XPS analysis from survey and high-resolution spectra, respectively. Variable amounts of carbon (68%-80.5%), nitrogen (10%-2.4%), and oxygen (20.8%-16.5%) were detected on the surface of the biological tissue. Chlorine, phosphorous sodium, and sulfur were also identified in lower extends. Besides that, analysis of the C 1s high-resolution spectra for the same two regions (ECM and PM ones) showed that a compromise between C-C (41.8 at. %) and C-N/C-O (35.6 at. %) amounts may indicate a strong presence of amino acids and proteoglycans on the ECM fragment-rich region, while the great amount of C-C (70.1 at. %) on the PM fragment-rich region is attributed to the large chains of fatty acids connected to phospholipid molecules. The micrometer-scale imaging of these chemical states on tissue was accomplished through XPEEM analysis. The C-C presence was found uniformly distributed across the entire analyzed area, while C-N/C-O and C=O were in two distinct regions. The combination of ToF-SIMS, XPS, and XPEEM is shown here as a powerful, noninvasive approach to map out elemental and chemical properties of biological tissues, i.e., identification of chemically distinct regions, followed by quantification of the surface chemical composition in each distinct region.

Individual behavioral differences and health of golden-headed lion tamarins (Leontopithecus chrysomelas).

Individual behavioral differences may influence how animals cope with altered environments. Depending on their behavioral traits, individuals may thus vary in how their health is affected by environmental conditions. We investigated the relationship between individual behavior of free-living golden-headed lion tamarins (Leontopithecus chrysomelas) responding to a novel object (to assess exploration-avoidance), and their habitat use and health status (endoparasitism; clinical measures: biometric data, heart rate, respiratory frequency, and temperature; fecal glucocorticoid metabolites). As parasite transmission can be affected by individual variation in social contact and social grooming, we also evaluated whether more sociable individuals show higher endoparasite loads compared with less sociable animals. Four groups living in landscapes with different levels of human disturbance were investigated: two in degraded forest fragments in an agricultural matrix (DFAM-higher disturbance), and two in a cocoa agroforestry system (cabruca-lower disturbance) in the Atlantic forest of South Bahia, Brazil. Using a subjective ratings approach, highly correlated adjective descriptors were combined to produce z-score ratings of one derived variable ("confidence"), which was selected to characterize the tamarins' exploration/avoidance responses during a novel object test. The higher the confidence score, the longer female tamarins spent foraging for prey independent of landscape, and the greater their body mass independent of sex and landscape. Only DFAM individuals showed intestinal parasite infection. Endoparasite loads were positively correlated with the number of grooming partners, suggesting an association between social grooming and transmission (more groomers = more endoparasites). Individual behavior, including in a test situation, may thus have some predictive value for behavior in a free-living context, and for its health consequences.

Umur Relatif Batuan Asal Sedimen Olisostrom Formasi Karangsambung, Kebumen, Jawa Tengah

The Karangsambung Formation in Kebumen, Central Java is olisostrome deposit that composed of floating rock fragments in the claystone matrix. The age of this formation is still debatable, and it is even unclear that the present age was the age of the formation or the age of the source rock of the olisostrome sediment. In this study, the relative age of the source rock of the olisostrome sediment was identified by using foraminifera data. The relative age identification of the olisostrome source rocks are very important as the identification of olisostrome sediment age is very difficult. The relative age of Karangsambung Formation can be assumed younger than the age of the olisostrome source rocks. Result of Karangsambung Formation age identification with regard to the olisostrome concep will have implications to the regional tectonic model of Java.Keywords: Karangsambung Formation, relative age, source rock, foraminifera, olisostrome.

Improvement of m/z accuracy for linear matrix‐assisted laser desorption/ionization time‐of‐flight mass spectrometer

RATIONALE Linear MALDI-TOF MS is a widely used in analytical and biomedical applications. The use of delayed extraction increases the resolution, but the roughness of the matrix crystals and the target plate misalignment in order of a few μm cause substantial spread in the ion time-of-flight values and decrease mass accuracy. METHODS: The method of mass spectra correction based on the correlation of matrix fragments peaks in MALDI mass spectra was used. The experiments were performed with the MALDI-TOF instrument CMI-1600 built by Guangzhou Hexin Instrument Co., Ltd. SIMION 8.1 and MATLAB were used for ion motion simulations. Data analysis was done using the home built custom developed software and MATLAB. RESULTS: It was shown that the drift of peak position in the MALDI-TOF MS mass spectra depends linearly on the time-of-flight in a wide mass range. While using the linear correction of the time-of-flight scale, an increase in m/z accuracy of more than 10 times was achieved. The mass accuracy is limited by the resolution of the fast ADC used. CONSLUSION It is expected that the proposed method will significantly increase the dynamic range, since it becomes possible to sum up corrected individual mass spectra without significant loss of resolution. The time scale adjusting can be used both for the linear time-of-flight instruments and for the reflector systems of various configurations.

Люминесцентные свойства разнолигандных beta-дикетонатов неодима, полученных в среде сверхкритического диоксида углерода в полимерных матрицах различной природы

Multi-ligand phosphor complexes of neodymium acetylacetonate with phenanthroline are synthesized in polymer matrices (oligourethane methacrylate, fluoroplast, polycarbonate) in supercritical carbon dioxide medium. At the same time the role of one of the ligands in such complexes is played by fragments of the polymer matrix. The luminescence spectra of the obtained ternary systems are described. It was shown that the position of the luminescence maxima is bathochromically shifted relative to the binary systems Nd(Acac)3/polymer obtained in a similar way and the magnitude of the shift depends on the nature of the polymer matrix. It was shown that upon the introduction of these components into polymers from a solution, similar phosphor mixed-ligand neodymium complexes do not form. The formation of new structures Nd(Acac)3/Phen/polymer upon impregnation of oligourethane methacrylate with neodymium β-diketonate and phenanthroline in a supercritical CO2 medium was confirmed by the method of differential thermal analysis. The same method confirmed that with the introduction of these components from the solution of the above systems do not form.

Wietrzenie mrozowe wybranych skał tatrzańskich w świetle badań laboratoryjny = Frost weathering of selected Tatra rocks in the light of laboratory tests

The aim of the work described here was to determine the rate of frost weathering for selected types of rock, and the manner in which this proceeds. The authors attempts to answer questions regarding progress with the disintegration of a given type of rock over time; the size and shape of weathered grains; the role played by fissures in rock and rock texture; and further relevant properties like compressive and tensile strength, porosity and water absorption. The rock samples used in laboratory testing were collected in the catchment area of the Chochołowski Stream in the Western Tatra Mountains of Poland. The seven types of rock analysed were white and brown granite, organodetric limestone, fine-grained conglomerate, dolomite breccia, quartzite sandstone and amphibolite. Samples were subjected to simulated frost weathering via the impact of repeated thermal cycles across a temperature range of -5 to +10°C. The simulation was carried out at the Low Temperatures Laboratory of the Institute of Geography and Spatial Management of Kraków’s Jagiellonian University, using a CI/1400/LT/2D cooling device. As testing was in progress, changes in the states of samples were determined through the measurement of dry and saturated mass and water absorption, as well as the speed at which an ultrasonic wave passed through. By reference to results for these measures, it was possible to calculate the frost weathering index after Matsuoke, i.e.:Rf= (Vp0-Vpk)/(Vp0*k) [cykle -1],where Vp0 is wave speed at cycle 0 (in km/s), Vpk is wave speed at cycle k (km/s) and k is the number of cycles. Rock dissolution tests and measurements of the products of weathering were also carried out. Values obtained for the index were used to rank the rocks tested for their resistance to frost weathering, as was the percentage of material in the initial mass that became subject to rock weathering. The least-resistant rock proved to be dolomite breccia, and the most-resistant amphibolites and quartzite sandstones. The rankings of other rocks varied in line with the indicative parameter referred to. The testing of physical properties suggested several reasons for high resistance to frost weathering among the analysed types of rock from the Western Tatras, i.e. the limited (<5%) open porosity noted for all types, limited water absorption, high compressive and tensile strength, compactness and homogeneity, low densities of fissures in samples in their initial state, almost complete filling of pores with matrix (e.g. in sandstone and conglomerate), re-filling of cracks (e.g. in limestone), and a significant component of resistant quartz. No effect of rock texture on resistance to frost weathering could be observed, but the presence of carbon matrix and carbonate rock fragments is important. The latter dissolve steadily, creating more favourable conditions for physical weathering (e.g. of amphibolites and conglomerates). The occurrence of mineral veins within rocks determines disintegration routes (e.g. in conglomerates). Given that rocks were subjected to an average of 850 repeated thermal cycles in the laboratory, the simulation achieved was of approx. 50 years of frost weathering under natural conditions in the study area. Experiments of this kind thus offer insight into processes running very slowly under natural conditions.

A onça no condomínio: o papel dos corredores ecológicos urbanos

Espaços livres podem proporcionar habitat para fauna nativa em áreas urbanas, mas espécies de maior porte são raramente avistadas. Uma onça parda (Puma concolor) foi capturada em vídeo em Piracicaba, SP, o que despertou o interesse em investigar quais padrões paisagísticos (formas, dimensões, relações espaciais entre a matriz urbana, corredores e fragmentos de habitats, vegetação etc.) possibilitaram os deslocamentos da zona rural para uma cidade de aproximadamente 400 mil habitantes. Utilizaram-se imagens de satélite, fotografias e mapas interpretativos. A onça foi avistada em dois pontos próximos, dos quais foram traçadas rotas para identificar prováveis percursos e refúgios. Os possíveis corredores ecológicos identificados incluem espaços sob linhas de transmissão de energia elétrica cercados por muros de condomínios, matas ciliares ao longo de córregos e do rio Piracicaba ou mesmo avenidas arborizadas que permeiam a cidade, conectam a matriz urbana com áreas rurais e dão acesso a fontes de alimentos (capivaras, animais domésticos). A presença do felino na área urbana pode decorrer de condições que o expulsaram de seus habitats, mas também de elementos atrativos e de padrões paisagísticos que criaram corredores ecológicos e propiciaram seus deslocamentos pela cidade.

Three‐dimensional soft tissue preservation revealed in the skin of a non‐avian dinosaur

AbstractThe most commonly preserved soft tissues associated with ornithischian dinosaurs are skin remains. The apparent resistance of hadrosaur skin to decay, and its abundance in the fossil record relative to that of other tetrapods, has been attributed to factors such as thickness and composition. Here we report additional intrinsic factors within hadrosaur skin: 3D‐preserved eumelanin‐bearing bodies, dermal cells and blood vessel fragments in an organic matrix composed of protein fossilization products. The skin is much thinner than that of living mammals of similar size. It is likely that the preservation of hadrosaur skin is related to the arrangement of the layers composing it.

Bone Tissue Regeneration in the Oral and Maxillofacial Region: A Review on the Application of Stem Cells and New Strategies to Improve Vascularization.

Bone tissue engineering techniques are a promising alternative for the use of autologous bone grafts to reconstruct bone defects in the oral and maxillofacial region. However, for successful bone regeneration, adequate vascularization is a prerequisite. This review presents and discusses the application of stem cells and new strategies to improve vascularization, which may lead to feasible clinical applications. Multiple sources of stem cells have been investigated for bone tissue engineering. The stromal vascular fraction (SVF) of human adipose tissue is considered a promising single source for a heterogeneous population of essential cells with, amongst others, osteogenic and angiogenic potential. Enhanced vascularization of tissue-engineered grafts can be achieved by different mechanisms: vascular ingrowth directed from the surrounding host tissue to the implanted graft, vice versa, or concomitantly. Vascular ingrowth into the implanted graft can be enhanced by (i) optimizing the material properties of scaffolds and (ii) their bioactivation by incorporation of growth factors or cell seeding. Vascular ingrowth directed from the implanted graft towards the host tissue can be achieved by incorporating the graft with either (i) preformed microvascular networks or (ii) microvascular fragments (MF). The latter may have stimulating actions on both vascular ingrowth and outgrowth, since they contain angiogenic stem cells like SVF, as well as vascularized matrix fragments. Both adipose tissue-derived SVF and MF are cell sources with clinical feasibility due to their large quantities that can be harvested and applied in a one-step surgical procedure. During the past years, important advancements of stem cell application and vascularization in bone tissue regeneration have been made. The development of engineered in vitro 3D models mimicking the bone defect environment would facilitate new strategies in bone tissue engineering. Successful clinical application requires innovative future investigations enhancing vascularization.

Generation of block-and-ash flows at the onset of silicic volcanism in the Paraná Magmatic Province (Brazil): evidence from photoanalysis of Caxias do Sul breccias

In this work, we perform textural analysis on volcanic breccias related to the silicic magmatism in the region of Sao Marcos (southern Brazil), Parana Magmatic Province. The breccias are matrix-supported, coarse-grained, poorly sorted with angular to rounded fragments in a fine-grained matrix. Juvenile fragments are dense to pumiceous, massive to banded dacites; lithic fragments were not recognised. The analyses were performed on field photographs. Grain size distribution (GSD) analysis showed maximum fragment sizes between − 8 and − 9.5 ϕ and smallest recognised sizes between − 3 and 1.5 ϕ. Due to the spatial resolution limit of the photographs and the weathered condition of the matrix, the fine fragments from the matrix were not analysed. The GSD fractality could be quantified by a single power law, with low/moderate D values of 1.9–2.3. Vesicle size distribution (VSD) and shape parameters of both fragments and vesicles were also measured. The fragments are typically low vesicularity, with median vesicle area fractions around 5% for all samples, but pumiceous fragments with up to 43% area are found. VSDs exhibit single exponential, concave upwards curves, with vesicles becoming more deformed/complex with increasing size, suggesting a single continuous process of nucleation and growth under low degrees of shear. Regarding the fragments’ shape parameters, all samples have high values of solidity which, together with the low-vesicularity of the fragments, suggest brittle fragmentation of poorly vesicular material and the operation of secondary fragmentation processes during transport that round and smooth the clasts. However, field evidence for local conduit systems together with the GSD fractality suggest that these may be proximal deposits, without substantial transport history. Based on a comparison of the deposits’ characteristics with several types of volcanic breccias, we propose a block and ash flow source for these breccias that indicate the presence of nearby lava domes, providing evidence for high-viscosity low-flux dacitic volcanism in the Parana Magmatic Province.

A conceptual approach to the formation of paramagnetic nanospecies of noble metals

Abstract The general concepts are analyzed regarding the approach for the formation of paramagnetic species of noble metals, with a non-rigid (labile) molecule being used as a supporting matrix. The formation of the metal nanospecies follows three stages: (i) the metal ions are captured by the matrix, (ii) the reducing agent causes formation of individual atoms separated by the matrix fragments, (iii) the individual atoms agglomerate due to conformational transformations of the labile molecule-matrix. This algorithm is realized in two distinct systems: Ag-containing nanospecies embedded within the system of polyacrylic acid (PAA) chains grafted to the film of fluorinated ethylene propylene copolymer (FEP) and Au-containing nanospecies in the free matrix of tannin-citrate- oxo-hydroxo aluminate. The evolution of the electron paramagnetic resonance (EPR) spectra while cooling down demonstrates the appearance of the exchange interaction which is suppressed at higher temperatures by the vibrational modes of the molecule-matrix. The role of the oxo-hydroxo aluminate form is one of a molecular motor sorting the individual nanospecies by their size and charge state.