Cytotoxicity and fibroblast properties during in vitro test of biphasic calcium phosphate/poly-dl-lactide-co-glycolide biocomposites and different phosphate materials

Reconstruction of bone defects is one of the major therapeutic goals in various clinical fields. Bone replacement materials must satisfy a number of criteria. Biological criteria are biocompatibility, controlled biodegradability, and osteoconductive or even osteogenic potential. The material should have a three-dimensional structure with an interconnected pore system so as to permit cell growth and transport of substances. The surface must permit cell adhesion and proliferation. Composite biomaterials have enormous potential for natural bone tissue reparation, filling and augmentation. Calcium hydroxyapatite/polymer composite biomaterials belong to this group of composites and, because of their osteoconductive and biocompatible properties, can be successfully implemented within bone tissue reparations. In this study, possible differences between BCP/DLPLG, pure BCP, and Bio-Oss materials were examined in vitro. During overnight incubations, fibroblast and fibroblast-like cells (L929, MRC5) were able to adhere, spread, and remain viable on BCP, BCP/PLGA, and Bio-Oss discs, as was evidenced by using light- and LVSEM-microscopy. Inhibiting influence over the cell growth is more pronounced in the cases of BCP usage on both cell lines--41.29% for L929 and 43.08% for MRC-5 cells. MRC-5 cells are, within the given experimental conditions, less sensitive on inhibiting effects for the materials BCP/PLGA and Bio-Oss (10.13% and 10.76%, respectively) than for the L929 cell lines (23.02% and 15.44%, respectively).     

Degradative side reactions in the syntheses of exactly alternating silarylene-siloxane polymers

Summary Four principal synthetic methods for preparation of exactly alternating silarylene-siloxane polymers: the chlorosilane, the acetoxysilane, the aminosilane and the ureidosilane polymerization reactions, were compared under equivalent experimental conditions. As indicated earlier, polymers with considerably different molecular weights were obtained. The highest molecular weight polymer resulted from the ureidosilane reaction, while the lowest ones were obtained from the chlorosilane and the acetoxysilane routes. Because thorough precautions were taken to ensure equally favorable conditions in all preparations, these results seem to support a hypothesis that the latter two reactions are limited by the occurrence of degradative desilytation side reactions which are inherent to the nature of these polymerization systems.Dedicated to Professor Dragutin Fle on the occasion of his 70th birthday     

Exactly alternating silarylene–siloxane polymers. I. The synthesis and stability of bis(1,1-tetramethylene-3-phenylureido)dimethylsilane

Ureidosilanes have been found to be active monomers for the preparation of siloxane polymers by step-growth polymerization reactions at low temperatures. For this purpose, very high monomer purities are required, and the present investigation was concerned with the purity and stability of bis(1,1-tetramethylene-3-phenylureido)dimethylsilane prepared from the diaminosilane and phenyl isocyanate. Preparation of the monomer by this reaction at ?20°C gave directly a product of very high purity suitable for the preparation of very high molecular weight polymers. Pseudo-first-order rate constants were obtained on the hydrolysis of the monomer during synthesis and storage.     

Single-Walled Carbon Nanotubes Modify Leaf Micromorphology,Chloroplast Ultrastructure and Photosynthetic Activity of Pea Plants

Single-walled carbon nanotubes (SWCNTs) emerge as promising novel carbon-based nanoparticles for use in biomedicine, pharmacology and precision agriculture. They were shown to penetrate cell walls and membranes and to physically interact and exchange electrons with photosynthetic complexes in vitro. Here, for the first time, we studied the concentration-dependent effect of foliar application of copolymer-grafted SWCNTs on the structural and functional characteristics of intact pea plants. The lowest used concentration of 10 mg L⁻¹ did not cause any harmful effects on the studied leaf characteristics, while abundant epicuticular wax generation on both leaf surfaces was observed after 300 mg L⁻¹ treatment. Swelling of both the granal and the stromal regions of thylakoid membranes was detected after application of 100 mg L⁻¹ and was most pronounced after 300 mg L⁻¹. Higher SWCNT doses lead to impaired photosynthesis in terms of lower proton motive force generation, slower generation of non-photochemical quenching and reduced zeaxanthin content; however, the photosystem II function was largely preserved. Our results clearly indicate that SWCNTs affect the photosynthetic apparatus in a concentration-dependent manner. Low doses (10 mg L⁻¹) of SWCNTs appear to be a safe suitable object for future development of nanocarriers for substances that are beneficial for plant growth.     

A new IoT‐based smart energy meter for smart grids

The significant increase in energy consumption by the growth of the population or by the use of new equipment has brought big challenges to the energy security as well as the environment. There is a need that consumers can track their daily use and understand consumption standards for better organizing themselves to obtain financial and energetic efficiency. With the improvement of smart networks technology for better energy supply, a smart meter is not just a simple measurement gadget anymore, but it has additional functions including smart equipment control, bidirectional communication that allows integration of users and networks, and other functionalities. Smart meters are the most fundamental components in smart power grids. Besides, the meters used with a management system can be utilized for monitoring and controlling home appliances and other gadgets according to the users' need. A solution of an integrated and single system should be more efficient and economical. Smart measurement systems allow monitoring the energy consumption of the final consumers while providing useful information about the energy quality. The information provided by these systems is used by the operators to enhance the energy supply, and different techniques can be also applied for this end, such as charge scheduling, management from the demand side, and non‐intrusive load monitoring. The Internet of Things (IoT) is becoming a great ally in the management of smart distribution and energy consumption in smart systems scenarios. To address these issues, this paper proposes and demonstrates a new smart energy meter following an IoT approach and its associated costs and benefits. The developed device incorporates several communication interfaces. In order to easily integrate with any monitoring software solution, the meter has a multi‐protocol connection. Finally, the provided solution is validated and demonstrated in real‐life environments and it is also under use.     

Economic Policy Uncertainty Index Meets Ensemble Learning

Computational Economics - We utilize a battery of ensemble learning techniques [ensemble linear regression (LM), random forest], as well as two gradient boosting techniques [Gradient Boosting...     

Impact of short-term heat pre-treatment at 50 °C on the toxicity of contact insecticides to adults of three Sitophilus granarius (L.) populations

The effect of short-term heat pre-treatment on the toxicity of contact insecticides was tested on Sitophilus granarius adults from three populations in order to examine possible interactions. In the laboratory: (a) weevil paralysis time (PT) after start of direct exposure to 50 °C; (b) the impact of three short-term heat pre-treatments at 50 °C (PT₂₀, PT₅₀ and PT₈₀) on the 24 and 72 h recovery rates of laboratory (Lab) strain adults exposed to one of five insecticides on filter papers; and (c) deltamethrin and dichlorvos toxicity to weevils of two populations with altered insecticide susceptibility after exposure to 50 °C over the PT₈₀ interval, were determined.The PT₉₉ values for weevils after exposure to 50 °C showed that the population selected with pirimiphos-methyl had the longest paralysis time. Previous heat treatments of the Lab strain for the PT₂₀ and PT₅₀ intervals had little impact on the toxicity of the insecticides, chlorpyrifos-methyl being the most toxic with the first interval, deltamethrin with the second, while malathion was the least toxic. However, after heat treatment of the Lab strain over the PT₈₀ and after a 72-h recovery period, deltamethrin and dichlorvos showed reduced toxicity, while chlorpyrifos-methyl was the most toxic insecticide and malathion again the least toxic.For field and selected weevils, heat pre-treatment at 50 °C over the PT₈₀ increased deltamethrin and dichlorvos toxicity to selected populations, but not to field populations when compared to their toxicity without pre-heating. Deltamethrin and dichlorvos toxicity after a 72-h recovery period from heat treatment over the PT₈₀ was higher to the selected population than to the resistant field population. Compared to the Lab strain, deltamethrin demonstrated lower toxicity to selected weevils and especially to a field population, while dichlorvos was considerably more toxic to both populations.