Electrochemical activity of Li2FeTiO4 and Li2MnTiO4 as potential active materials for Li ion batteries: A comparison with Li2NiTiO4

We demonstrate, for the first time, a considerable electrochemical activity of two members of lithium transition element titanates: Li₂FeTiO₄ and Li₂MnTiO₄. Both materials consist of 10–20 nm particles embedded in a conductive carbon coating. We show that not the coating but the small particle size is decisive for materials’ activity. Li₂FeTiO₄ shows a stable reversible capacity of up to 123 mA hg⁻¹ at C/20 and 60 °C which is 83% of the theoretical value for exchange of 1 electron (148 mA hg⁻¹). Li₂MnTiO₄ could only be prepared in a nanosized form that contained about 30% of impurities. The capacity of the whole material (including impurities) is comparable to that of Li₂FeTiO₄ but the cycling stability is much poorer. In contrast to the Fe and Mn analogues, the third member of the titanate family, Li₂NiTiO₄, shows a good electrochemistry even when the particle size is much larger (about 100 nm). During initial cycles at C/10 and 60 °C, exchange of more than 1 electron per compound formula has been observed. The cycling stability at high temperatures, however, is poor.     

Interplay between nematic ordering and thermomechanical response in a side-chain liquid single crystal elastomer containing pendant azomesogen units

Photoactive materials based on azobenzene derivatives exhibit interesting properties related to the reversible photo-isomerisation between the trans and cis isomers of the azo-compound. In this work we report the preparation and physical-chemical characterization of Liquid Single Crystal Elastomers (LSCEs) containing azobenzene derivative side-chain mesogens as co-monomer. The interplay between the orientational ordering and mechanical response in the nematic phase is investigated by thermomechanical measurements as well as by deuteron NMR spectroscopy. We demonstrate that local nematic order can be reliably probed in azo-LSCEs using low molar mass deuterated cyanobiphenyl nematogen in low concentrations. No phase separation of the dopant is observed. The nematoelastic coupling eav(T)∝Sav(T) between the effective sample deformation and average nematic order parameter is present over a wide temperature range even in the systems with relatively large heterogeneity of the nematic order and misaligned nematic domains.     

A Novel Artificial Hemoglobin Carrier Based on Heulandite-Calcium Mesoporous Aluminosilicate Particles

Tetraethyl-orthosilicate (TEOS)-based nanoparticles are most extensively used as a silica-based hemoglobin carrier system. However, TEOS-based nanoparticles induce adverse effects on the hemoglobin structure. Therefore, a heulandite-calcium-based carrier was investigated as a novel silica-based hemoglobin carrier system. The heulandite-calcium mesoporous aluminosilicate particles (MSPs) were fabricated by a patented tribo-mechanical activation process, according to the manufacturer, and its structure was assessed by X-ray diffraction analysis. Upon hemoglobin encapsulation, alternation in the secondary and tertiary structure was observed. The hemoglobin-particle interactions do not cause heme degradation or decreased activity. Once encapsulated inside the particle pores, the hemoglobin shows increased thermal stability, and higher loading capacity per gram of particles (by a factor of >1.4) when compared to TEOS-based nanoparticles. Futhermore, we introduced a PEGlyted lipid bilayer which significantly decreases the premature hemoglobin release and increases the colloidal stability. The newly developed hemoglobin carrier shows no cytotoxicity to human umbilical vein endothelial cells (HUVEC).     

Extracellular Vesicles and Antiphospholipid Syndrome: State-of-the-Art and Future Challenges

Antiphospholipid syndrome (APS) is a systemic autoimmune disorder characterized by thromboembolism, obstetric complications, and the presence of antiphospholipid antibodies (aPL). Extracellular vesicles (EVs) play a key role in intercellular communication and connectivity and are known to be involved in endothelial and vascular pathologies. Despite well-characterized in vitro and in vivo models of APS pathology, the field of EVs remains largely unexplored. This review recapitulates recent findings on the role of EVs in APS, focusing on their contribution to endothelial dysfunction. Several studies have found that APS patients with a history of thrombotic events have increased levels of EVs, particularly of endothelial origin. In obstetric APS, research on plasma levels of EVs is limited, but it appears that levels of EVs are increased. In general, there is evidence that EVs activate endothelial cells, exhibit proinflammatory and procoagulant effects, interact directly with cell receptors, and transfer biological material. Future studies on EVs in APS may provide new insights into APS pathology and reveal their potential as biomarkers to identify patients at increased risk.     

In diffusion and electronic energy structure in polymer layers on In tin oxide

We have investigated the effect of In diffusion on the electronic structure of a polyethylenedioxythiophene-poly (styrenesulfonate) layer deposited on InSn_xO_1 − x substrate by photoelectron spectroscopy. We observe additional states near the highest occupied molecular orbital of the polymer layer that are generated by In releases from the substrate. Also, we observe that In diffusion continues into an overlayer of a mixture of poly(3-hexylthiophene) and [6,6]-phenyl C61-butyric acid methyl ester. On the basis of the results of the numerical line shape analysis of In 3d_5/2 core level emission, we rule out the presence of metallic In clusters within the organic layers and suggest instead that In/sulfur compounds are present within the organic layers.     

Selenium uptake and species distribution in selenium-enriched bean (<Emphasis Type="Italic">Phaseolus vulgaris</Emphasis> L.) seeds obtained by two different cultivations

In this work, bean plants were cultivated in two different ways using two modes of selenium supplementation in the form of sodium selenate. Each group consisted of the same four cultivars. Group A plants were grown in soil and twice foliarly sprayed at an interval of 10 days with an aqueous solution of 10 mg Se L⁻¹ at flowering time. Group B plants were hydroponically cultivated after the maternal seeds were soaked in nutrient solution containing the same Se content as used for foliar fertilisation. Bean seeds obtained from group A plants accumulated much more Se (around 2 μg g⁻¹ dry weight) than those seeds obtained from group B plants (around 0.6 μg g⁻¹ dry weight). No differences in Se content within each group were found. After enzyme hydrolysis, 85±7% of soluble selenium was found in group A and 65±2% of soluble Se in group B with respect to the total Se content in seeds. In bean seed supernatants SeMeSeCys, SeMet and two unknown species were found. These four species together represented 79±8 and 53±9% of the Se mass fraction of group A and group B, respectively. No differences in the presence of selenium species were found between the four cultivars and cultivation conditions.     

Determination of 210Pb and 210Po in Sediments, Water, and Plants in an Area Contaminated with Mine Waste

We compared the activities of ²¹⁰Pb and ²¹⁰Po in samples of reeds with the concentrations in sediment and water, and estimated the capability of bioaccumulation of these radionuclides in the reeds. The results showed that there are very high levels of ²¹⁰Pb and ²¹⁰Po in sediment from the Boršt stream, where mill tailings were transported. The reeds accumulate ²¹⁰Pb to a slightly higher extent than ²¹⁰Po and in this way help to decontaminate the water, which then flows via a channel into the Todraščica stream. We also observed that the stream possessed a good self-cleaning capability. The Jazbec waste pile, where spoils and lower grade ores were disposed of, is not badly contaminated with ²¹⁰Pb and ²¹⁰Po, and has little influence on the environment.     

Internal oxidation of Ag–VC composites

The internal oxidation (IO) of Ag–VC composites containing 5 vol.% of carbide was examined at three oxidation temperatures (350, 400, 600 °C). Two mechanisms were observed due to the formation of double oxides with relatively low-melting points. At temperatures below the lowest eutectic point in situ, or diffusion less IO, was observed with the formation and growth of oxide layers surrounding the initial carbide. At temperatures above the eutectic point IO resulted in the formation of liquid oxide pools, which grew in size and developed into a network of oxides within the metal matrix. The kinetics confirmed the presence of two distinct mechanisms.     

Li2MnSiO4 as a potential Li-battery cathode material

Recently we synthesized and preliminary characterized a new material for potential use in Li-battery cathodes: Li₂MnSiO₄. Although its theoretical capacity is about 330 mAh g⁻¹, the actual measurements showed a much smaller value (about 120 mAh g⁻¹). One of the reasons for the poor performance could be the poor electronic conductivity (<10⁻¹⁴ S cm⁻¹ at RT) causing a huge polarization during charge–discharge. However, in the present paper we show that reducing the particle size down to the range of 20–50 nm and additional particle embedment into a carbon phase does not significantly improve the electrochemistry of Li₂MnSiO₄. Observations of structural changes during the first charge shows a complete loss of peaks when reaching the nominal composition of ca. Li₁MnSiO₄. The peaks are not recovered during subsequent cycling. It is supposed that extraction of Li causes significant structural changes so that the resulting material is only able to reversibly exchange a limited amount of Li.