Two-step sinter-crystallization of K2O–CaO–P2O5–SiO2 (45S5-K) bioactive glass

Bioactive glasses and glass-ceramics (GCs) effectively regenerate bone tissue, however most GCs show improved mechanical properties. In this work, we developed and tested a rarely studied bioactive glass composition (24.4K₂O-26.9CaO-46.1SiO₂-2.6P₂O₅ mol%, identified as 45S5-K) with different particle sizes and heating rates to obtain a sintered GC that combines good fracture strength, low elastic modulus, and bioactivity. We analyzed the influence of the sintering processing conditions in the elastic modulus, Vickers microhardness, density, and crystal phase formation in the GC. The best GC shows improved properties compared with its parent glass. This glass achieves a good densification degree with a two-step viscous flow sintering approach and the resulting GC shows as high bioactivity as that of the standard 45S5 Bioglass®. Furthermore, the GC elastic modulus (56 GPa) is relatively low, minimizing stress shielding. Therefore, we unveiled the glass sintering behavior with concurrent crystallization of this complex bioactive glass composition and developed a potential GC for bone regeneration.     

Covalent Linkage and Macrocylization Preserve and Enhance Synergistic Interactions in Catalytic Amyloids

The self-assembly of short peptides into catalytic amyloid-like nanomaterials has proven to be a powerful tool in both understanding the evolution of early proteins and identifying new catalysts for practically useful chemical reactions. Here we demonstrate that both parallel and antiparallel arrangements of β-sheets can accommodate metal ions in catalytically productive coordination environments. Moreover, synergistic relationships, identified in catalytic amyloid mixtures, can be captured in macrocyclic and sheet-loop-sheet species, that offer faster rates of assembly and provide more complex asymmetric arrangements of functional groups, thus paving the way for future designs of amyloid-like catalytic proteins. Our findings show how initial catalytic activity in amyloid assemblies can be propagated and improved in more-complex molecules, providing another link in a complex evolutionary chain between short, potentially abiotically produced peptides and modern-day enzymes.     

Foliar Spraying of Silicon Associated with Salicylic Acid Increases Silicon Absorption and Peanut Growth

Silicon - Silicon (Si) combined with foliar spraying of salicylic acid (SA) can affect the absorption of this beneficial element. A study with Si non-accumulators plants (soybean and bean) observed...     

Ozonated Mineral Oil: Preparation,Characterization and Evaluation of the Microbicidal Activity

The ozonation of vegetable oils has been studied, since the produced ointments have antibacterial and fungicidal activities. However, the ozonation of mineral oils has not been reported in the literature yet, opening an interesting field for examination. In this work, we have shown the ozonation of a commercial mineral oil (Nujol). The main goal was to produce oils containing free ozone, so that this gas could act as antimicrobial agent. It was found that in Nujol, ozone remains for at least 40 days and in the sample ozonized for 15 h its concentration was 7.5 mg mL^?1. Neat Nujol showed no antimicrobial activity against the tested microorganisms, however, when ozonated it showed antimicrobial activity against Enterococcus faecalis, Staphylococcus aureus and Escherichia coli.     

Stability of rigid blocks exposed to single-pulse excitation

This paper proposes a numerical procedure that can predict the minimum duration of a rectangular, half-cycle sine wave, linearly increasing and triangular single-pulse excitation required to overturn the rigid block resting on a moving base. Since the linearization assumption in the derivation of an analytical solution, which has already been used by Housner and other researchers, cannot be valid for a block with various slenderness ratios and dimensions, a derivation of numerical solutions which would be valid for all types of block is necessary. The proposed numerical procedure takes into account the possibility of sliding and uplifting of the block from the base. The numerical algorithm for the proposed numerical procedure in a commercial code C++ is given in the “Appendix.”     

Mechanochemical Synthesis and Characterization of Nanocrystalline Copper-Cobalt Ferrites

Nanocrystalline copper-cobalt ferrites with composition Cu_(1-x)Co_xFe_2O_4,where x = 0.2 and 0.8,were synthesized by mechanochemical treatment of co-precipitated precursors.The ferrite powders were characterized by XRD and Mossbauer spectroscopy.Results proved obtaining of spinel ferrites with crystallite size smaller than 10 nm.Increasing of crystallite size of samples with increasing of mechanochemical treatment duration was established,too.Catalytic properties of obtained ferrites were tested in reactions of oxidation of CO,methanol and dimethyl ether.High catalytic activity of nanocrystalline copper-cobalt ferrites toward CO and CH_3OH(about 100% conversions of CO and CH_3OH at 160 ℃)and moderate activity toward(CH_3)_2O oxidation were established.The results obtained revealed that the Co/Cu atomic ratio is an important factor determinant the behavior of catalysts toward methanol and DME oxidation.     

State-space ARIMA for supply-chain forecasting

ARIMA is seldom used in supply chains in practice. There are several reasons, not the least of which is the small sample size of available data, which restricts the usage of the model. Keeping in mind this restriction, we discuss in this paper a state-space ARIMA model with a single source of error and show how it can be efficiently used in the supply-chain context, especially in cases when only two seasonal cycles of data are available. We propose a new order selection algorithm for the model and compare its performance with the conventional ARIMA on real data. We show that the proposed model performs well in terms of both accuracy and computational time in comparison with other ARIMA implementations, which makes it efficient in the supply-chain context.     

An approach for evaluating collaboration attributes in cluster-based companies

This paper presents an approach for evaluating collaboration attributes in companies operating in industrial clusters. From the literature review, we identified governance, geographic proximity, and trust as the main collaboration attributes in industrial clusters. For each of them, there is a set of related sub-attributes that composed the evaluation model. For developing the model, we used the graph theoretic approach (GTA), a methodology for multi-attribute assessment that considers interdependencies among elements of a system to provide an overall evaluation. We applied the model to five companies of a furniture cluster. The results showed the model allows for systematizing relationship management because it highlights the collaboration attributes that need to be improved. Furthermore, the application of the model may contribute to encouraging companies to develop collaborative practices.