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Charakterystyki przeplywu materialow sypkich w silosach mają znaczenie dla naporow wywieranych na ściany silosu. Mozna je zmieniac za pomocą roznych wkladek. W pracy omowiono wyniki liczbowe dotyczące ograniczonego przeplywu niespoistego ziarnistego piasku w pelnowymiarowym silosie metalowym z roznymi symetrycznie rozmieszczonymi wkladami, sluzącymi do korekcji wzorca przeplywu (podwojny stozek, stozek w stozku i odwrocony stozek). Do symulacji dynamicznego przeplywu piasku w silosie zastosowano metode punktu materialnego (MPM). Do opisu zachowania plyniecia piasku niespoistego przyjeto hipoplastyczny model konstytutywny. Nacisk polozono na schematy przeplywu i napory na ściany i wkladki silosu. Wyniki liczbowe zostaly bezpośrednio porownane z odpowiednimi eksperymentami w silosie pelnowymiarowym. Osiągnieto zadowalającą zgodnośc wynikow liczbowych i eksperymentalnych. W obliczeniach MPM zbadano rowniez wplyw początkowego wspolczynnika porowatości piasku, kąta tarcia ściany silosu, polozenia wkladki silosowej i rozmiaru komorek siatki MPM.

The aim of this work was to develop new method for the production of chitosan/agarose (CHN/A) film that could serve as a potential artificial skin substitute for regenerative medicine applications. Within this new production method, the concentrations of biomaterial components (chitosan in CH3COOH and agarose in NaOH) were optimized to provide neutralization of the resultant mixture up to pH approx. 6.0 without uncontrolled precipitation (gelation) of chitosan constituent. Produced thin film was subjected to comprehensive evaluation of its biomedical potential by determination of mechanical, physicochemical, and biological properties. It was demonstrated that the developed CHN/A film reveals slightly acidic pH of 5.98 known to support skin regeneration, high exudate absorption capacity, and is prone to biodegradation in simulated enzymatic wound environment. Performed tensile test proved high elastic deformations of the film (Young's modulus = 0.02 MPa, elongation at break = 23%) in a wet state, which would allow suitable stretching after application at the wound site. Moreover, novel biomaterial is non-toxic and supports fibroblast growth on its surface. Based on the obtained results it may be concluded that the produced CHN/A film possesses all necessary features of the artificial skin substitute.

Key points Rhythmic processes in living organisms are controlled by biological clocks. The orexinergic system of the lateral hypothalamus carries circadian information to provide arousal for the brain during the active phase.Here, we show that orexins exert an excitatory action in three parts of the lateral geniculate nucleus (LGN), in particular upon directly retinorecipient neurons in the non‐image forming visual structures.We provide evidence for the high nocturnal levels of orexins with stable circadian expression of predominant orexin receptor 2 in the LGN.Our data additionally establish the convergence of orexinergic and pituitary adenylate cyclase (PAC)‐activating peptide/PAC1 receptor systems (used by melanopsin‐expressing retinal ganglion cells), which directly regulates responses to the retinal input.These results help us better understand circadian orexinergic control over the non‐image forming subcortical visual system, forming the animal's preparedness for the behaviourally active night. Abstract The orexinergic system of the lateral hypothalamus is tightly interlinked with the master circadian clock and displays daily variation in activity to provide arousal‐related excitation for the plethora of brain structures in a circadian manner. Here, using a combination of electrophysiological, optogenetic, histological, molecular and neuronal tracing methods, we explore a particular link between orexinergic and visual systems in rat. The results of the present study demonstrate that orexinergic fibre density at the area of subcortical visual system exerts a clear day to night variability, reaching a maximum at behaviourally active night. We also show pronounced electrophysiological activations of neurons in the lateral geniculate nucleus by orexin A through 24 h, via identified distinct orexin receptors, with the ventrolateral geniculate displaying a daily cycle of responsiveness. In addition, for the first time, we provide a direct evidence for orexins to act on retinorecipient neurons with a high convergence of orexinergic and putatively retinal pituitary adenylate cyclase (PAC)‐activating peptide/PAC1 receptor systems. Altogether, the present study ties orexins to non‐image forming visual structures with implications for circadian orexinergic modulation of neurons, which process information on ambient light levels., Key points Rhythmic processes in living organisms are controlled by biological clocks. The orexinergic system of the lateral hypothalamus carries circadian information to provide arousal for the brain during the active phase.Here, we show that orexins exert an excitatory action in three parts of the lateral geniculate nucleus (LGN), in particular upon directly retinorecipient neurons in the non‐image forming visual structures.We provide evidence for the high nocturnal levels of orexins with stable circadian expression of predominant orexin receptor 2 in the LGN.Our data additionally establish the convergence of orexinergic and pituitary adenylate cyclase (PAC)‐activating peptide/PAC1 receptor systems (used by melanopsin‐expressing retinal ganglion cells), which directly regulates responses to the retinal input.These results help us better understand circadian orexinergic control over the non‐image forming subcortical visual system, forming the animal's preparedness for the behaviourally active night.

A topical application of antibiotic-loaded wound dressings is recommended only for chronically infected wounds with poor vascularization. Thus, more often dressing materials loaded with antibacterial metal ions are produced. In turn, gentamicin sponges are commonly used to prevent surgical site infections. The aim of this study was to produce curdlan-based biomaterials enriched with gentamicin and zinc (Zn)-doped nano-hydroxyapatite to prevent wound and surgical site infections. Developed biomaterials were subjected to basic microstructural characterization, cytotoxicity test against human skin fibroblasts (BJ cell line), and comprehensive microbiological experiments using Staphylococcus aureus and Pseudomonas aeruginosa strains. To evaluate the in vivo healing capacity of the developed biomaterials, severely infected chronic wound in a veterinary patient was treated with the use of gentamicin-loaded dressing. Fabricated biomaterials were characterized by a highly porous microstructure with high plasma absorption capacity (approx. 7 mL/g for Zn-loaded biomaterial and 13 mL/g for gentamicin-enriched dressing) and optimal water vapor transmission rate (approx. 1700 g/m

Many biomaterials for bone regeneration have recently been produced using thermally gelled curdlan (1,3-ß-d-glucan) as a binder for bioceramics. As the human organism does not produce enzymes having the ability to degrade curdlan, it is not clear what is the fate of curdlan gel after its implantation in the bone. To clarify this point, in this research osteoclasts were cultured on the curdlan gel to show its degradation by acidic hydrolysis. The studies clearly demonstrated microstructural (AFM and SEM imaging) and chemical changes (Raman spectroscopy) on the curdlan surface caused by osteoclast culture. Moreover, degradation test in a cell-free system using HCl solution (pH = 4.5), mimicking environment in the resorption lacuna, showed great weight loss of the sample, release of glucose, and chemical changes typical of curdlan degradation. Thus, the presented research for the first time provides a strong evidence of osteoclast-mediated acidic hydrolysis of thermally obtained curdlan gel.

Bioactive dressings are usually produced using natural or synthetic polymers. Recently, special attention has been paid to β-glucans that act as immunomodulators and have pro-healing properties. The aim of this research was to use β-1,3-glucan (curdlan) as a base for the production of bioactive dressing materials (curdlan/agarose and curdlan/chitosan) that were additionally enriched with vitamin C and/or hydrocortisone to improve healing of chronic and burn wounds. The secondary goal of the study was to compressively evaluate biological properties of the biomaterials. In this work, it was shown that vitamin C/hydrocortisone-enriched biomaterials exhibited faster vitamin C release profile than hydrocortisone. Consecutive release of the drugs is a desired phenomenon since it protects wounds against accumulation of high and toxic concentrations of the bioactive molecules. Moreover, biomaterials showed gradual release of low doses of the hydrocortisone, which is beneficial during management of burn wounds with hypergranulation tissue. Among all tested variants of biomaterials, dressing materials enriched with hydrocortisone and a mixture of vitamin C/hydrocortisone showed the best therapeutic potential since they had the ability to significantly reduce MMP-2 synthesis by macrophages and increase TGF-β1 release by skin cells. Moreover, materials containing hydrocortisone and its blend with vitamin C stimulated type I collagen deposition by fibroblasts and positively affected their migration and proliferation. Results of the experiments clearly showed that the developed biomaterials enriched with bioactive agents may be promising dressings for the management of non-healing chronic and burn wounds.

Using a method based on the spectrophotometric analysis of the liquids remaining after washing ceramic granules, the type of impurity was determined, the wavelength for measuring the impurity was established, and the type of cuvette (polystyrene or quartz) was analyzed. The absorbance of the samples was measured at wavelengths between 190 and 1100 nm. The results showed that both cuvette types are useful; however, the greatest absorbances were detected using quartz ones at low wavelengths around 190 nm. The comparison of absorption spectra from the samples, centrifuged and noncentrifuged, enabled us to define the impurities as small apatite particles.

Composite structures exhibiting a periodic arrangement of building blocks can be found in natural systems at different length scales. Recreating such systems in artificial composites using the principles of self-assembly has been a great challenge, especially for 1D microscale systems. Here, we present a purposely designed composite material consisting of gold nanoparticles and a nematic liquid crystal matrix that has the ability to self-create a periodic structure in the form of a one-dimensional photonic lattice through a phase separation process occurring in a confined space. Our strategy is based on the use of a thermoswitchable medium that reversibly and quickly responds to both heating and cooling. We find that the period of the structure is strongly related to the size of the confining space. We believe that our findings will allow us to not only better understand the phase separation process in multicomponent soft/colloid mixtures with useful optical properties but also improve our understanding of the precise assembly of advanced materials into one-dimensional periodic systems, with prospective applications in future photonic technologies.

Single-molecule localization microscopy (SMLM), while well established for cultured cells, is not yet fully compatible with tissue-scale samples. We introduce single-molecule oblique-plane microscopy (obSTORM), which by directly imaging oblique sections of samples with oblique light-sheet illumination offers a deep and volumetric SMLM platform that is convenient for standard tissue samples and small intact animals. We demonstrate super-resolution imaging at depths of up to 66 µm for cells, Caenorhabditis elegans gonads, Drosophila melanogaster larval brain, mouse retina and brain sections, and whole stickleback fish. Single-molecule oblique-plane microscopy (obSTORM) enables deep volumetric super-resolution imaging in a light-sheet microscopy platform that is convenient for standard tissues and small intact animals.

The reaction of monolayer graphene with aryl diazonium salts is a popular approach for functionalizing graphene under ambient conditions. We here apply interference reflection microscopy (IRM), a label-free optical technique, to study the in situ reaction dynamics of the representative diazonium reaction of graphene with 4-nitrobenzenediazonium tetrafluoroborate (4-NBD) at high spatiotemporal resolution and further correlate results with atomic force microscopy, Raman spectroscopy, and infrared scattering scanning near-field optical microscopy. Interestingly, we find the reaction to be significantly promoted by a low (0.5 W/cm2) level of blue visible light, whereas at the same intensity level, red light has negligible effects on reaction rate. We further report rich spatial heterogeneities for the reaction, including enhanced reactivity at graphene edges and an unexpected flake-to-flake variation in reaction rate. Moreover, we demonstrate direct photopatterning for the 4-NBD functionalization, achieving 400 nm patterning resolution.

We unveil the reaction dynamics of monolayer graphene in electrochemical oxidation and reduction processes through interference reflection optical microscopy. At 300 nm spatial resolution and 200 ms temporal resolution, we reveal rapid electrochemical oxidation of graphene, as well as its efficient electrochemical reduction back to the unoxidized state. We identify 1.4 V (vs Ag/AgCl) as the onset voltage for oxidation and show that the process is driven by free radicals generated in the electrolysis of water and so fully suppressible by a radical-trapping molecule. Moreover, we find the oxidation process to be spatially heterogeneous at the nanoscale, defect- and history-dependent, and characterized by a self-limiting effect unique to the two-dimensional system. We further demonstrate that electrochemical reduction rapidly reverses the oxidized graphene back to the unoxidized state in a controlled manner and find strong dependency of reduction speed on the reduction voltage and pH, from which we conclude a one-to-one relationship between protons and electrons in the reduction process. Besides elucidating the electrochemical reaction mechanisms of graphene, our results point to new pathways to the controlled generation and fine-tuning of graphene derivatives through electrochemistry.

Development of bone scaffolds that are nontoxic to eukaryotic cells, while revealing bactericidal activity still remains a huge challenge for the scientific community. It should be noted that only bacteriostatic (the ability of the biomaterial to inhibit the growth of bacteria) and bactericidal (the ability to kill99.9 % bacteria) activities have clinical importance. Unfortunately, many material scientists are confused with the microbiological definition of antibacterial action and consider biomaterials causing reduction in colony-forming units (CFUs) by 50-80 % as promising antibacterial implants. The aim of this study was to synthesize three variants of Zn-doped hydroxyapatite (HA) nanopowder, which were characterized by different content of Zn

Composite, helical nanostructures formed using cooperative interactions of liquid crystals and Au nanoparticles were studied using a scanning transmission electron microscopy (STEM) mode. The investigated helical assemblies exhibit long-range hierarchical order across length scales, as a result of the crystallization (freezing) directed growth mechanism of nanoparticle-coated twisted nanoribbons and their ability to form organized bundles. Here, STEM methods were used to reproduce the 3D structure of the Au nanoparticle double helix.

Osteosarcoma (OSA) is the most common malignant bone neoplasia in humans and dogs. In dogs, treatment consists of surgery in combination with chemotherapy (mostly carboplatin and/or doxorubicin (Dox)). Chemotherapy is often rendered ineffective by multidrug resistance. Previous studies have revealed that Dox conjugated with 4 nm glutathione-stabilized gold nanoparticles (Au-GSH-Dox) enhanced the anti-tumor activity and cytotoxicity of Dox in Dox-resistant feline fibrosarcoma cell lines exhibiting high P-glycoprotein (P-gp) activity. The present study investigated the influence of Au-GSH-Dox on the canine OSA cell line D17 and its relationship with P-gp activity. A human Dox-sensitive OSA cell line, U2OS, served as the negative control. Au-GSH-Dox, compared to free Dox, presented a greater cytotoxic effect on D17 (IC50 values for Au-GSH-Dox and Dox were 7.9 μg/mL and 15.2 μg/mL, respectively) but not on the U2OS cell line. All concentrations of Au-GSH (ranging from 10 to 1000 μg/mL) were non-toxic in both cell lines. Inhibition of the D17 cell line with 100 μM verapamil resulted in an increase in free Dox but not in intracellular Au-GSH-Dox. The results indicate that Au-GSH-Dox may act as an effective drug in canine OSA by bypassing P-gp.

Intervertebral cages made of Ti6Al4V alloy show excellent osteoconductivity, but also higher stiffness, compared to commonly used polyether-ether-ketone (PEEK) materials, that may lead to a stress-shielding effect and implant subsidence. In this study, a metallic intervertebral fusion cage, with improved mechanical behavior, was manufactured by the introduction of a three-dimensional (3D) mesh structure to Ti6Al4V material, using an additive manufacturing method. Then, the mechanical and biological properties of the following were compared: (1) PEEK, with a solid structure, (2) 3D-printed Ti6Al4V, with a solid structure, and (3) 3D-printed Ti6Al4V, with a mesh structure. A load-induced subsidence test demonstrated that the 3D-printed mesh Ti6Al4V cage had significantly lower tendency (by 15%) to subside compared to the PEEK implant. Biological assessment of the samples proved that all tested materials were biocompatible. However, both titanium samples (solid and mesh) were characterized by significantly higher bioactivity, osteoconductivity, and mineralization ability, compared to PEEK. Moreover, osteoblasts revealed stronger adhesion to the surface of the Ti6Al4V samples compared to PEEK material. Thus, it was clearly shown that the 3D-printed mesh Ti6Al4V cage possesses all the features for optimal spinal implant, since it carries low risk of implant subsidence and provides good osseointegration at the bone-implant interface.

Modern bone tissue engineering is based on the use of implants in the form of biomaterials, which are used as scaffolds for osteoprogenitor or stem cells. The task of the scaffolds is to temporarily sustain the function, proliferation and differentiation of bone tissue to enable its regeneration. The aim of this work is to use the macro ATR-FTIR spectroscopic imaging for analysis of the ceramic-based biomaterial (chitosan/β-1,3-glucan/hydroxyapatite). Specifically, during long-term culture of mesenchymal cells derived from adipose tissue (ADSCs) and bone marrow (BMDSCs) on the surface of scaffold. Infrared spectroscopy allows the acquisition of information on both the organic and inorganic parts of the tested composite. This innovative spectroscopic approach proved to be very suitable for studying the formation of new bone tissue and ECM components, sample staining and demineralization are not required and consequently the approach is rapid and cost-effective. The novelty of this study focuses on the innovatory use of ATR-FTIR imaging to evaluate the molecular structure and maturity of collagen as well as mineral matrix formation and crystallization in the context of bone regenerative medicine. Our research has shown that the biomaterial investigated on this work facilitates the formation of valid bone ECM of the stem cells types studied, as a result of the synthesis of type I collagen and mineral content deposition. Nevertheless, ADSC cells have been proven to produce a greater amount of collagen with a lower content of helical secondary structures, at the same time showing a higher mineralization intensity compared to BMDSC cells. Considering the above results, it could be stated that the developed scaffold is a promising material for biomedical applications, including modification of bone implants to increase their biocompatibility.

During meiosis, pairing between homologous chromosomes is stabilized by the assembly of a protein lattice known as the synaptonemal complex (SC). The SC ensures the formation of crossovers between homologous chromosomes and also regulates their distribution. However, how the SC regulates crossover formation remains elusive. We isolated an unusual mutation inC. elegansthat disrupts crossover interference but not the assembly of the SC. This mutation alters the unique C-terminal domain of an essential SC protein, SYP-4, a likely ortholog of the vertebrate SC protein SIX6OS1. To characterize the structure of the SC in wild-type and mutant animals, we use three-dimensional STochastic Optical Reconstruction Microscopy (3D-STORM) to interrogate the molecular architecture of the SC in intact germline tissue fromC. elegans. The approach enabled us to define positions of protein epitopes with respect to the 3D architecture of this complex. Using a probabilistic mapping approach to analyze super-resolution image data, we detect a marked structural transition in wild-type animals that coincides with crossover designation. We also found that oursyp-4mutant subtly perturbs SC architecture. Our findings add to growing evidence that the SC is an active material whose molecular organization contributes to chromosome-wide crossover regulation.

Low-temperature atmospheric pressure plasma was demonstrated to have an ability to generate different reactive oxygen and nitrogen species (RONS), showing wide biological actions. Within this study, mesoporous silica nanoparticles (NPs) and FexOy/NPs catalysts were produced and embedded in the polysaccharide matrix of chitosan/curdlan/hydroxyapatite biomaterial. Then, basic physicochemical and structural characterization of the NPs and biomaterials was performed. The primary aim of this work was to evaluate the impact of the combined action of cold nitrogen plasma and the materials produced on proliferation and osteogenic differentiation of human adipose tissue-derived mesenchymal stem cells (ADSCs), which were seeded onto the bone scaffolds containing NPs or FexOy/NPs catalysts. Incorporation of catalysts into the structure of the biomaterial was expected to enhance the formation of plasma-induced RONS, thereby improving stem cell behavior. The results obtained clearly demonstrated that short-time (16s) exposure of ADSCs to nitrogen plasma accelerated proliferation of cells grown on the biomaterial containing FexOy/NPs catalysts and increased osteocalcin production by the cells cultured on the scaffold containing pure NPs. Plasma activation of FexOy/NPs-loaded biomaterial resulted in the formation of appropriate amounts of oxygen-based reactive species that had positive impact on stem cell proliferation and at the same time did not negatively affect their osteogenic differentiation. Therefore, plasma-activated FexOy/NPs-loaded biomaterial is characterized by improved biocompatibility and has great clinical potential to be used in regenerative medicine applications to improve bone healing process.

International audience; In this article, we show how advanced hierarchical structures of topological defects in the so-called smectic oily streaks can be used to sequentially transfer their geometrical features to gold nanospheres. We use two kinds of topological defects, 1D dislocations and 2D ribbon-like topological defects. The large trapping efficiency of the smectic dislocation cores not only surpasses that of the elastically distorted zones around the cores but also the one of the 2D ribbon-like topological defect. This enables the formation of a large number of aligned NP chains, within the dislocation cores that can be quasi-fully filled without any significant aggregation outside the cores. When the NP concentration is large enough to entirely fill the dislocation cores, the LC confinement varies from 1D to 2D. We demonstrate that the 2D topological defect cores induce a confinement that leads to planar hexagonal networks of NPs. We then draw the phase diagram driven by NP concentration, associated with the sequential confinements induced by these two kinds of topological defects. Owing to the excellent large-scale order of these defect cores, not only the NP chains but also the NP hexagonal networks can be oriented along the desired direction, suggesting a possible new route for the creation of either 1D or 2D highly anisotropic NP networks. In addition, these results open rich perspectives based on the possible creation of coexisting NP assemblies of different kinds, localized in different confining areas of a same smectic film that would thus interact thanks to their proximity but also would interact via the surrounding soft matter matrix.

The article discusses issues related with storage of granular materials in silos made of corrugated sheets and reinforced with vertical ribs. Advantages and disadvantages of these structures are named, and typical technological solutions used by largest silo producers are presented. Moreover, basic assumptions of Eurocode 3 are discussed in the context of determining the buckling load capacity of a ribbed jacket. Alternative methods are indicated to determine the silo stability using analytical and FEM based methods. General conclusions are formulated with respect to designing of silos made of corrugated sheets.

Under ambient conditions, the behavior of a solid surface is often dominated by a molecularly thin adsorbed layer (adlayer) of small molecules. Here we develop an optical approach to unveil the nanoscale structure and composition of small-molecule adlayers on glass surfaces through spectrally resolved super-resolution microscopy. By recording the images and emission spectra of millions of individual solvatochromic molecules that turn fluorescent in the adlayer phase, we obtain ~30 nm spatial resolution and achieve concurrent measurement of local polarity. This allows us to establish that the adlayer dimensionality gradually increases through a sequence of 0D (nanodroplets), 1D (nano-lines), and 2D (films) for liquids of increasing polarity. Moreover, we find that in adlayers, a solution of two miscible liquids spontaneously demixes into nanodroplets of different compositions that correlate strongly with droplet size and location. We thus reveal unexpectedly rich structural and compositional behaviors of surface adlayers at the nanoscale., Characterization of adsorbed molecular layers on surfaces is the key to wide-ranging applications, but elucidating the structure and composition of such adlayers remains challenging. Here the authors develop an approach to unveil the nanoscale structure and composition of adlayers through spectrally resolved super-resolution microscopy.

The paper deals with buckling of cylindrical metal silos with corrugated sheets and columns. Attention was paid to local buckling of cold-formed open-sectional thin-walled columns in metal cylindrical silos with corrugated sheets. The effect of the column profile dimensions, silo height, silo diameter, corrugated wall thickness, column number/column distance, corrugation height and bulk solid's type was comprehensively investigated. Three-dimensional linear bifurcation analyses were performed for silos using the finite element method and compared with analytical formulae of Eurocode 3. Based on calculation outcomes some recommendations for silo dimensioning were elaborated.

Benthic habitat mapping is a rapidly growing field of underwater remote sensing studies. This study provides the first insight for high-resolution hydroacoustic surveys in the Slupsk Bank Natura 2000 site, one of the most valuable sites in the Polish Exclusive Zone of the Southern Baltic. This study developed a quick and transparent, automatic classification workflow based on multibeam echosounder and side-scan sonar surveys to classify benthic habitats in eight study sites within the Slupsk Bank. Different predictor variables, four supervised classifiers, and the generalisation approach, improving the accuracy of the developed model were evaluated. The results suggested a very high significance for the classification performance of specific geomorphometric features that were not used in benthic habitat mapping before. These include, e.g., Fuzzy Landform Element Classification, Multiresolution Index of the Valley Bottom Flatness, and Multiresolution Index of the Ridge Top Flatness. Comparison of classification results with manual maps demonstrated that Random Forest had the highest performance of four tested supervised classifiers. Because the current needs include benthic habitat mapping for the whole area of the Polish Exclusive Economic Zone, the key findings of this study may be further applied to extensive areas in the Polish waters and other vast areas worldwide.

In this paper we present a new environment called MERPSYS that allows simulation of parallel application execution time on cluster-based systems. The environment offers a modeling application using the Java language extended with methods representing message passing type communication routines. It also offers a graphical interface for building a system model that incorporates various hardware components such as CPUs, GPUs, interconnects and easily allows various formulas to model execution and communication times of particular blocks of code. A simulator engine within the MERPSYS environment simulates execution of the application that consists of processes with various codes, to which distinct labels are assigned. The simulator runs one Java thread per label and scales computations and communication times adequately. This approach allows fast coarse-grained simulation of large applications on large-scale systems. We have performed tests and verification of results from the simulator for three real parallel applications implemented with C/MPI and run on real HPC clusters: a master-slave code computing similarity measures of points in a multidimensional space, a geometric single program multiple data parallel application with heat distribution and a divide-and-conquer application performing merge sort. In all cases the simulator gave results very similar to the real ones on configurations tested up to 1000 processes. Furthermore, it allowed us to make predictions of execution times on configurations beyond the hardware resources available to us.

The potential of rising two-dimensional materials, such as graphene, can be substantially expanded through chemistry. However, it has been a challenge to study how chemical reactions of two-dimensional materials progress. Existing techniques offer limited signal contrast and/or spatial-temporal resolution and are difficult to apply to in situ studies. Here we employ an optical approach, namely interference reflection microscopy, to quantitatively monitor the redox reaction dynamics of graphene and graphene oxide (GO) in situ with diffraction-limited (∼300 nm) spatial resolution and video-rate time resolution. Remarkably, we found that the oxidation kinetics of graphene is characterized by a seeded, autocatalytic process that gives rise to unique, wave-like propagation of reaction in two dimensions. The reaction is initially slow and confined to highly localized, nanoscale hot spots associated with structural defects, but then self-accelerates while propagating outward, hence flower-like, micrometer-sized reaction patterns over the entire sample. In contrast, the reduction of GO is spatially homogeneous and temporally pseudo-first-order, and through in situ data, we further identify pH as a key reaction parameter.

The paper describes experimental investigation results on wheat flow in a medium-size steel cylindrical flat bottom silo with horizontally corrugated walls and columns composed of open-sectional thin-walled profiles. Several experiments on silo filling and emptying with wheat were performed by inducing a different flow pattern. The following quantities were measured in the silo: horizontal wall pressures, wall frictional tractions and vertical reaction forces under columns. Horizontal wall pressures and wall frictional tractions were registered along the silo height and silo circumference in the lower silo region during three different flow patterns: mass flow, mixed mass-funnel flow and eccentric flow. Experimental results were compared with Eurocode 1. Some discrepancies between experiments and code formulae were observed.

Highly reactive bioceramics deprive culture medium of Ca 2+ ions which is lethal to the cells in vitro . The aim of this work was to demonstrate that new method for HA/glucan scaffold fabrication, involving calcium as a cross-linker for β-1,3-glucan gel, may support cell survival in vitro when highly reactive bioceramics are the component of the biomaterial. Two composites made of highly reactive hydroxyapatite (HA) and β-1,3-glucan were prepared basing on 2 different methods. Then, ion reactivity of the materials and cell behaviour on their surfaces were compared. Obtained results proved that new method for HA/β-1,3-glucan fabrication protects against Ca 2+ uptake by reactive HA supporting osteoblast growth in vitro .

Correlative microscopy, the integration of two or more microscopy techniques performed on the same sample, produces results that emphasize the strengths of each technique while offsetting their individual weaknesses. Light microscopy has historically been a central method in correlative microscopy due to its widespread availability, compatibility with hydrated and live biological samples, and excellent molecular specificity through fluorescence labeling. However, conventional light microscopy can only achieve a resolution of ∼300 nm, undercutting its advantages in correlations with higher-resolution methods. The rise of super-resolution microscopy (SRM) over the past decade has drastically improved the resolution of light microscopy to ∼10 nm, thus creating exciting new opportunities and challenges for correlative microscopy. Here we review how these challenges are addressed to effectively correlate SRM with other microscopy techniques, including light microscopy, electron microscopy, cryomicroscopy, atomic force microscopy, and various forms of spectroscopy. Though we emphasize biological studies, we also discuss the application of correlative SRM to materials characterization and single-molecule reactions. Finally, we point out current limitations and discuss possible future improvements and advances. We thus demonstrate how a correlative approach adds new dimensions of information and provides new opportunities in the fast-growing field of SRM.

Due to the high toxicity of currently used chemotherapeutics, novel methods of cancer treatment are needed. Gold nanoparticles (AuNPs) seem to be an interesting alternative due to penetration through biological membranes and systemic barriers. AuNPs as carriers of chemotherapeutics allow for reduced concentrations whilst maintaining the expected effect, and thus reducing the costs of therapy and adverse effects. We synthesized AuNPs stabilized with reduced glutathione (GSH) and conjugated with doxorubicin (DOX), gemcitabine (GEM) or cytarabine (CTA). This is the first study in which cytarabine-AuNPs were synthesized and characterized. Transmission electron microscopy (TEM), thermogravimetric analysis (TGA), nuclear magnetic resonance spectroscopy (NMR) and high-performance liquid chromatography (HPLC) were used to chemically characterize obtained nanoparticles. Antitumor activity and safety of application were assessed by MTT assay in in vitro model (human osteosarcoma cells -143B, human osteoblast- hFOB1.19, breast cancer cells - MCF7, breast epithelial cells - MCF10A, pancreatic cancer cells - PANC-1, and pancreatic cells - hTERT-HPNE cells). We have shown that cellular response varies according to the type and concentration of AuNPs. At some concentrations, we were able to show selective cytotoxicity of our AuNPs conjugates only to cancer cell lines. Synthesized nanoparticles were more cytotoxic to tumor cell lines than chemotherapeutics alone.

The availability of helical assemblies of plasmonic nanoparticles with precisely controlled and tunable structures can play a key role in the future development of chiral plasmonics and metamaterials. Here, a strategy to efficiently yield helical structures based on the cooperative interactions of liquid crystals and gold nanoparticles in thin films is developed. These nanocomposites exhibit exceptional long-range hierarchical order across length scales, which results from the growth mechanism of nanoparticle-coated twisted nanoribbons and their ability to form organized bundles. The helical assembly formation is governed by the presence of rationally functionalized nanoparticles. Importantly, the thickness of the achieved nanocomposites can be reversibly reconfigured owing to the polymorphic nature of the liquid crystal. The versatility of the proposed approach is demonstrated by preparing helices assembled from nanoparticles of different geometries and dimensions (spherical and rod-like). The described strategy may become an enabling technology for structuring nanoparticle assemblies with high precision and fabricating optically active materials.

Robust synthesis of large-scale self-assembled nanostructures with long-range organization and a prominent response to external stimuli is critical to their application in functional plasmonics. Here, the first example of a material made of liquid crystalline nanoparticles which exhibits UV-light responsive surface plasmon resonance in a condensed state is presented. To obtain the material, metal cores are grafted with two types of organic ligands. A promesogenic derivative softens the system and induces rich liquid crystal phase polymorphism. Second, an azobenzene derivative endows nanoparticles with photoresponsive properties. It is shown that nanoparticles covered with a mixture of these ligands assemble into long-range ordered structures which exhibit a novel dual-responsivity. The structure and plasmonic properties of the assemblies can be controlled by a change in temperature as well as by UV-light irradiation. These results present an efficient way to obtain bulk quantities of self-assembled nanostructured materials with stability that is unattainable by alternative methods such as matrix-assisted or DNA-mediated organization.

Purpose We studied the effects of silver nanoparticles (AgNPs) on human blood platelet function. We hypothesized that AgNPs, a known antimicrobial agent, can be used as blood-compatible, “ideal material’’ in medical devices or as a drug delivery system. Therefore, the aim of the current study was to investigate if functionalized AgNPs affect platelet function and platelets as well as endothelial cell viability in vitro. Methods AgNPs, functionalized with reduced glutathione (GSH), polyethylene glycol (PEG) and lipoic acid (LA) were synthesized. Quartz crystal microbalance with dissipation was used to measure the effect of AgNPs on platelet aggregation. Platelet aggregation was measured by changes in frequency and dissipation, and the presence of platelets on the sensor surface was confirmed and imaged by phase contrast microscopy. Flow cytometry was used to detect surface abundance of platelet receptors. Lactate dehydrogenase test was used to assess the potential cytotoxicity of AgNPs on human blood platelets, endothelial cells, and fibroblasts. Commercially available ELISA tests were used to measure the levels of thromboxane B2 and metalloproteinases (MMP-1, MMP-2) released by platelets as markers of platelet activation. Results 2 nm AgNPs-GSH, 3.7 nm AgNPs-PEG both at 50 and 100 µg/mL, and 2.5 nm AgNPs-LA at 100 µg/mL reduced platelet aggregation, inhibited collagen-mediated increase in total P-selectin and GPIIb/IIIa, TXB2 formation, MMP-1, and MMP-2 release. The tested AgNPs concentrations were not cytotoxic as they did not affect, platelet, endothelial cell, or fibroblast viability. Conclusion All tested functionalized AgNPs inhibited platelet aggregation at nontoxic concentrations. Therefore, functionalized AgNPs can be used as an antiplatelet agent or in design and manufacturing of blood-facing medical devices, such as vascular grafts, stents, heart valves, and catheters.

In this work, we report a study of two thermotropic liquid crystalline samples showing a not common mesophase behavior. The samples, namely a di-benzyloxy biphenyl derivative labelled 9/2 RS/RS, and a bimesogenic liquid crystal labelled L1, show a direct transition between two isotropic phases followed, at lower temperatures, by the optically isotropic, 3D structured, cubic phase. These systems have been investigated by means of 1H NMR diffusometry and 1H NMR relaxometry in order to characterize their isotropic&ndash, isotropic&rsquo, &ndash, cubic mesophase behavior, mainly on the dynamic point of view. In particular, the temperature trend of the self-diffusion coefficients measured for both samples allowed us to significantly distinguish between the two isotropic phases, while the temperature dependence of the 1H spin-lattice relaxation time (T1) did not show significant discontinuities at the isotropic&ndash, phase transition. A preliminary analysis of the frequency-dependence of 1H T1 at different temperatures gives information about the main motional processes active in the isotropic mesophases.

Summary: Ion channels control sperm navigation within the female reproductive tract and, thus, are critical for their ability to find and fertilize an egg. The flagellar calcium channel CatSper controls sperm hyperactivated motility and is dependent on an alkaline cytoplasmic pH. The latter is accomplished by either proton transporters or, in human sperm, via the voltage-gated proton channel Hv1. To provide concerted regulation, ion channels and their regulatory proteins must be compartmentalized. Here, we describe flagellar regulatory nanodomains comprised of Hv1, CatSper, and its regulatory protein ABHD2. Super-resolution microscopy revealed that Hv1 is distributed asymmetrically within bilateral longitudinal lines and that inhibition of this channel leads to a decrease in sperm rotation along the long axis. We suggest that specific distribution of flagellar nanodomains provides a structural basis for the selective activation of CatSper and subsequent flagellar rotation. The latter, together with hyperactivated motility, enhances the fertility of sperm. : Miller et al. use super-resolution microscopy, electrophysiology, and electron microscopy to show that the sperm proton channel Hv1 forms bilateral lines positioned asymmetrically down the sperm flagellum. Hv1 inhibition leads to a decrease in sperm rotation, suggesting an important role for this channel in sperm motility. Keywords: hydrogen voltage-gated channel 1, Hv1, CatSper, STORM, super-resolution imaging, ion channels, rotation, sperm flagellum

While single-molecule localization microscopy (SMLM) offers superior super-resolution for biology, typical SMLM system using highly-inclined off-axis illumination limits an imaging depth to only a few microns from a coverslip surface. Alternative SMLM system using light-sheet illumination has extended the accessible depth for whole cells or small embryos, but may be less practical as it requires specialized or dedicated sample devices. Furthermore, for typical tissue samples (laterally a few millimeters or wider), the lateral lightsheet illumination is no longer applicable. Here, we demonstrate oblique light-sheet SMLM (obSTORM) that provides a facile and practical platform with a full compatibility with tissue samples. By using a single-objective, inclined lightsheet and directly detecting single molecules along the oblique plane, obSTORM opens new doors for tissue-level super-resolution imaging.

Effective management of chronic wounds with excessive exudate may be challenging for medical doctors. Over the years, there has been an increasing interest in the engineering of biomaterials, focusing on the development of polymer-based wound dressings to accelerate the healing of exuding wounds. The aim of this study was to use curdlan, which is known to support wound healing, as a base for the production of superabsorbent hybrid biomaterials (curdlan/agarose and curdlan/chitosan) with the intended use as wound dressings for highly exuding wound management. To evaluate the biomedical potential of the fabricated curdlan-based biomaterials, they were subjected to a comprehensive assessment of their microstructural, physicochemical, and biological properties. The obtained results showed that foam-like biomaterials with highly porous structure (66–77%) transform into soft gel after contact with the wound fluid, acting as typical hydrocolloid dressings. Novel biomaterials have the superabsorbent ability (1 g of the biomaterial absorbs approx. 15 ml of exudate) with horizontal wicking direction while keeping dry edges, and show water vapor transmission rate of approx. 1700–1800 g/m2/day which is recommended for optimal wound healing. Moreover, they are stable in the presence of collagenases, but prone to biodegradation in lysozyme solution (simulated infected wound environment). Importantly, the developed biomaterials are non-toxic and their surface hinders fibroblast attachment, which is essential during dressing changes to avoid damage to newly formed tissues in the wound bed. All mentioned features make the developed biomaterials promising candidates to be used as the wound dressings for the management of chronic wounds with moderate to high exudate.

There are many modern wound dressings that have promising properties for repairing skin damage. However, due to various types of wounds and the problems they cause, there is still a great demand for new, effective healing strategies. The aim of this study was to create superabsorbent wound dressing made of marine-derived polysaccharides (agarose and chitosan) using the freeze-drying method. The secondary goal was its comprehensive evaluation for potential use as an external superabsorbent bandage for wounds with high exudation. Due to the well-known positive effect of ascorbic acid (vitamin C) on the healing process, biomaterial enriched with vitamin C was prepared and compared to the variant without the addition of ascorbic acid. It was shown that the produced foam-like wound dressing had a very porous structure, which was characterized by hydrophilicity, allowing a large amount of human fluids to be absorbed. According to in vitro tests on human fibroblasts, biomaterial was nontoxic and supportive to cell proliferation. Vitamin C-enriched dressing also had the ability to significantly reduce matrix metalloproteinase-2 production and to promote platelet-derived growth factor-BB synthesis by fibroblasts, which is desired during chronic wound treatment. The material has features of the eco-friendly wound care product since it was made of naturally-derived polysaccharides and was proved to be biodegradable. Importantly, despite degradable character, it was stable in the chronic and infected wound microenvironment, maintaining high integrity after 8-week incubation in the enzymatic solutions containing lysozyme and collagenases. The obtained results clearly showed that developed biomaterial possesses all necessary features of the external dressing for the management of exudate from both acute and chronic non-healing wounds.

Permanent orthopedic/dental implants should reveal good osseointegration, which is defined as an ability of the biomaterial to form a direct connection with the surrounding host bone tissue after its implantation into the living organism. Currently, biomaterial osseointegration is confirmed exclusively with the use of in vivo animal tests. This study presents for the first time ex vivo determination of osseointegration process using human trabecular bone explant that was drilled and filled with the chitosan/curdlan/hydroxyapatite biomaterial, followed by its long-term culture under in vitro conditions. Within this study, it was clearly proved that tested biomaterial allows for the formation of the connection with bone explant since osteoblasts, having ability to produce bone extracellular matrix (type I collagen, fibronectin), were detected at a bone-implant interface by confocal laser scanning microscopy (CLSM) and scanning electron microscopy (SEM). Importantly, in this research it was demonstrated by Live/Dead staining and CLSM imaging that human bone explants may stay alive for a long period of time (at least approx. 50 days) during their culture under in vitro conditions. Therefore, ex vivo bone explant, which is a heterogeneous tissue containing many different cell types, may serve as an excellent model to test biomaterial osseointegration during comparative and preliminary studies, reducing animal tests which is compatible with the principles of ‘3Rs’, aiming to Replace, Reduce and Refine the use of animals wherever possible.