In the particular study, the micropatterning of the Ti5Al4V alloy in as-received, solution treated and solution and precipitated condition was done using electron beam surface modification (EBSM) by ...scanning electron beam. The nanostructured TiN/TiO2 films were deposited over the EBSM Ti5Al4V substrates using dc magnetron sputtering and cathodic arc and glow-discharge methods. The electrochemical potentiodynamic tests were performed in Ringer saline at 37±0.05 °C and a pH of 5.7 in order to determine the corrosion resistance behavior of the coated and uncoated EBSM substrates as compared with the bare as-received, solution treated and solution and precipitated samples. The presented results gave an idea of the corrosion behavior of the examined implant systems in aggressive environment and external conditions close to the body right.
In order to obtain a proper and accelerated osseointegration process, continuous efforts for improving the surface of the implants have been made. The physical texture, structure and mechanical ...properties of the implant surface are known to be an important factor in bone-implant interaction. Trying to find a solution for weak osseointegration, new modification techniques should be used and examined. In the particular study, the Ti5Al4V and Ti6Al4V alloys with different initial structure and composition were vacuum heat treated at different technological parameters in order to obtain maximum strengthening. One and the same electron beam surface modified (EBSM) by scanning electron beam was subsequently carried out for both alloys and their surface characteristics and mechanical properties were revealed by metallographic analysis, roughness, XRD and hardness measurements. The results revealed that under the selected conditions of treatment, a specific wave-like topography was obtained. The mean grains' sizes, depth of the structural changes after the surface modification and hardness and crystal lattices' changes of both alloys was assessed depending on the differences in the composition, initial structural and mechanical characteristics of the alloys in the different heat-treated conditions.
In photosynthesis, water is oxidized at a protein-bound Mn4Ca complex. Artificial water-oxidation catalysts that are similarly efficient and based on inexpensive and abundant materials are of great ...interest. Recently, assembly of a catalyst as an amorphous layer on inert cathodes by electrodeposition starting from an aqueous solution of cobalt ions and potassium phosphate has been reported. X-ray absorption spectroscopy on the cobalt catalyst film (CoCF) suggests that its central structural unit is a cluster of interconnected complete or incomplete CoIII−oxo cubanes. Potassium ligation to Co-bridging oxygens could result in Co3K(μ-O)4 cubanes, in analogy to the Mn3Ca(μ-O)4 cubane motif proposed for the photosynthetic Mn complex. The similarities in function and oxidative self-assembly of CoCF and the catalytic Mn complex in photosynthesis are striking. Our study establishes a close analogy also with respect to the metal−oxo core of the catalyst.
The cost of genome-wide association (GWA) studies can be prohibitively high when large samples are genotyped. We conducted a GWA study on schizophrenia (SZ) and to reduce the cost, we used DNA ...pooling. We used a parent-offspring trios design to avoid the potential problems of population stratification. We constructed pools from 605 unaffected controls, 574 SZ patients and a third pool from all the parents of the patients. We hybridized each pool eight times on Illumina HumanHap550 arrays. We estimated the allele frequencies of each pool from the averaged intensities of the arrays. The significance level of results in the trios sample was estimated on the basis of the allele frequencies in cases and non-transmitted pseudocontrols, taking into account the technical variability of the data. We selected the highest ranked SNPs for individual genotyping, after excluding poorly performing SNPs and those that showed a trend in the opposite direction in the control pool. We genotyped 63 SNPs in 574 trios and analysed the results with the transmission disequilibrium test. Forty of those were significant at P<0.05, with the best result at P=1.2 x 10(-6) for rs11064768. This SNP is within the gene CCDC60, a coiled-coil domain gene. The third best SNP (P=0.00016) is rs893703, within RBP1, a candidate gene for schizophrenia.
Context. The BL Lac object 3C 371 was observed by the Transiting Exoplanet Survey Satellite (TESS) for approximately a year, between July 2019 and July 2020, with an unmatched two-minute imaging ...cadence. In parallel, the Whole Earth Blazar Telescope (WEBT) Collaboration organized an extensive observing campaign, providing three years of continuous optical monitoring between 2018 and 2020. These datasets allow for a thorough investigation of the variability of the source. Aims. The goal of this study is to evaluate the optical variability of 3C 371. Taking advantage of the remarkable cadence of TESS data, we aim to characterize the intra-day variability (IDV) displayed by the source and identify its shortest variability timescale. With this estimate, constraints on the size of the emitting region and black hole mass can be calculated. Moreover, WEBT data are used to investigate long-term variability (LTV), including in terms of the spectral behavior of the source and the polarization variability. Based on the derived characteristics, we aim to extract information on the origin of the variability on different timescales. Methods. We evaluated the variability of 3C 371 by applying the variability amplitude tool, which quantifies variability of the emission. Moreover, we employed common tools, such as ANOVA (ANalysis Of VAariance) tests, wavelet and power spectral density (PSD) analyses to characterize the shortest variability timescales present in the emission and the underlying noise affecting the data. We evaluated the short- and long-term color behavior to understand its spectral behavior. The polarized emission was analyzed, studying its variability and possible rotation patterns of the electric vector position angle (EVPA). Flux distributions of the IDV and LTV were also studied with the aim being to link the flux variations to turbulent and/or accretion-disk-related processes. Results. Our ANOVA and wavelet analyses reveal several entangled variability timescales. We observe a clear increase in the variability amplitude with increasing width of the time intervals evaluated. We are also able to resolve significant variations on timescales of as little as ∼0.5 h. The PSD analysis reveals a red-noise spectrum with a break at IDV timescales. The spectral analysis shows a mild bluer-when-brighter (BWB) trend on long timescales. On short timescales, mixed BWB, achromatic and redder-when-brighter signatures can be observed. The polarized emission shows an interesting slow EVPA rotation during the flaring period, where a simple stochastic model can be excluded as the origin with a 3 σ significance. The flux distributions show a preference for a Gaussian model for the IDV, and suggest it may be linked to turbulent processes, while the LTV is better represented by a log-normal distribution and may have a disk-related origin.
Podophyllotoxin (PPT) is used in the industrial production of efficient anticancer, antiviral and other drugs.
or
are natural sources of PPT, but at present they are considered as endangered species. ...Their PPT content is variable, depending on the growing conditions. Searching for new sources of PPT, some representatives of the genus
were found to exhibit efficient PPT biosynthesis. However, PPT is highly toxic and poorly soluble in water compound, which limits its clinical applications. In this connection, amphiphilic polymer micelles are considered to be suitable PPT carriers, aimed at increase in water solubility and decrease in toxicity. The present research deals with the evaluation of MPEG-polycarbonate block copolymer micelles loaded with PPT or juniper extracts. The active component-loaded polymer nanocarriers were characterized by dynamic and electrophoretic light scattering, as well as by transmission electron microscopy. The active component loading efficiency and loading capacity were also determined. Highly efficient antiproliferative activity of the loaded micelles was determined in a panel of cancer cell lines. The obtained amphiphilic nanocarriers, loaded with PPT-containing bioactive components, have application in future in vivo preclinical trials of their pharmacokinetics and pharmacodynamics as potential therapeutical agents in the prospective nanomedicine.
ABSTRACT
In 2021 BL Lacertae underwent an extraordinary activity phase, which was intensively followed by the Whole Earth Blazar Telescope (WEBT) Collaboration. We present the WEBT optical data in ...the BVRI bands acquired at 36 observatories around the world. In mid-2021 the source showed its historical maximum, with R = 11.14. The light curves display many episodes of intraday variability, whose amplitude increases with source brightness, in agreement with a geometrical interpretation of the long-term flux behaviour. This is also supported by the long-term spectral variability, with an almost achromatic trend with brightness. In contrast, short-term variations are found to be strongly chromatic and are ascribed to energetic processes in the jet. We also analyse the optical polarimetric behaviour, finding evidence of a strong correlation between the intrinsic fast variations in flux density and those in polarization degree, with a time delay of about 13 h. This suggests a common physical origin. The overall behaviour of the source can be interpreted as the result of two mechanisms: variability on time-scales greater than several days is likely produced by orientation effects, while either shock waves propagating in the jet, or magnetic reconnection, possibly induced by kink instabilities in the jet, can explain variability on shorter time-scales. The latter scenario could also account for the appearance of quasi-periodic oscillations, with periods from a few days to a few hours, during outbursts, when the jet is more closely aligned with our line of sight and the time-scales are shortened by relativistic effects.
A synthetic procedure combining high energy ball-milling and calcination at 900 °C was applied to obtain mixed metal oxides of the type Zn
1−x
Ni
x
Fe
2
O
4
(x = 0.25; 0.5; 0.75). The formation of ...spinel-like structures and the phase composition were confirmed by XRD in combination with Mössbauer, IR and Raman spectroscopy. The crystallite size was analysed from X-ray diffraction data revealing nanometric crystallites with an average size in the interval 20–60 nm. The IR spectra showed two fundamental absorption bands in the range 650–400 cm
−1
, which are characteristics of the metal-oxygen vibrations in tetrahedral and octahedral configurations. The mixed metal oxides were tested as catalysts for the decomposition of methanol to syngas and the degradation of the water pollutant malachite green in model solutions under UV light irradiation. Both the catalytic and photocatalytic activities were found to increase with increasing content of Ni(II) in the mixed metal oxides. The reduction behaviour of the samples was characterized by temperature-programmed reduction—thermogravimetric analysis and related to the catalytic conversion of methanol in the presence of the oxides. The most active samples for malachite degradation had the lowest band gap energy of 1.43 and 1.45 eV. The measurements of the reaction liquor by atomic absorption spectroscopy verified the stability of the samples tested as photocatalysts during the photocatalytic test.
Graphic Abstract
Zn/Ni ferrites of the type Zn
1−x
Ni
x
Fe
2
O
4
(x = 0.25; 0.5; 0.75) active both as catalysts for methanol conversion (a) and malachite green decomposition in model solutions under UV light irradiation (b)
The development of molecular psychiatry in the last few decades identified a number of candidate genes that could be associated with schizophrenia. A great number of studies often result with ...controversial and non-conclusive outputs. However, it was determined that each of the implicated candidates would independently have a minor effect on the susceptibility to that disease. Herein we report results from our replication study for association using 255 Bulgarian patients with schizophrenia and schizoaffective disorder and 556 Bulgarian healthy controls. We have selected from the literatures 202 single nucleotide polymorphisms (SNPs) in 59 candidate genes, which previously were implicated in disease susceptibility, and we have genotyped them. Of the 183 SNPs successfully genotyped, only 1 SNP, rs6277 (C957T) in the DRD2 gene (P=0.0010, odds ratio=1.76), was considered to be significantly associated with schizophrenia after the replication study using independent sample sets. Our findings support one of the most widely considered hypotheses for schizophrenia etiology, the dopaminergic hypothesis.
Coxiella burnetii in ticks and wild birds Tokarevich, N.K.; Panferova, Yu.A.; Freylikhman, O.A. ...
Ticks and tick-borne diseases,
February 2019, 2019-02-00, 20190201, Volume:
10, Issue:
2
Journal Article
Peer reviewed
The study objective was to get more information on C. burnetii prevalence in wild birds and ticks feeding on them, and the potentialities of the pathogen dissemination over Europe by both.
Blood, ...blood sera, feces of wild birds and ticks removed from those birds or from vegetation were studied at two sites in Russia: the Curonian Spit (site KK), and the vicinity of St. Petersburg (site SPb), and at two sites in Bulgaria: the Atanasovsko Lake (site AL), and the vicinity of Sofia (site SR).
C. burnetii DNA was detected in blood, feces, and ticks by PCR (polymerase chain reaction). All positive results were confirmed by Sanger's sequencing of 16SrRNA gene target fragments. The antibodies to C. burnetii in sera were detected by CFR (complement fixation reaction).
Eleven of 55 bird species captured at KK site hosted Ixodes ricinus.
C. burnetii DNA was detected in three I. ricinus nymphs removed from one bird (Erithacus rubecula), and in adult ticks flagged from vegetation: 0.7% I. persulcatus (site SPb), 0.9% I. ricinus (site KK), 1.0% D. reticulatus (AL site). C. burnetii DNA was also detected in 1.4% of bird blood samples at SPb site, and in 0.5% of those at AL site. Antibodies to C. burnetii were found in 8.1% of bird sera (site SPb). C. burnetii DNA was revealed in feces of birds: 0.6% at AL site, and 13.7% at SR site.
Both molecular-genetic and immunological methods were applied to confirm the role of birds as a natural reservoir of C. burnetii. The places of wild bird stopover in Russia (Baltic region) and in Bulgaria (Atanasovsko Lake and Sofia region) proved to be natural foci of C. burnetii infection. Migratory birds are likely to act as efficient “vehicles” in dispersal of C. burnetii -infested ixodid ticks.
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