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P2X7R, β3-integrin and Cx-43 mediate interaction between astrocytes and adjacent autoreactive immune cells
Get PDFAstrocytes form a dense meshwork throughout the central nervous system (CNS) which qualifies them to perform interactive maintenance functions with neighboring cells. In neuroinflammation, this astroglial cell-to-cell interaction varies which can either promote or lessen pathological processes (1,2). In multiple sclerosis (MS), astrocytes engage in an interaction with immune cells which drives neurodegeneration by creating and sustaining an inflammatory CNS environment (3). Previously, we showed that CNS-infiltrated immune cells (CNS-IICs) in the experimental autoimmune encephalomyelitis (EAE) rat, rapidly alter the activity pattern of astrocytes by activating glial P2X7receptor (P2X7R)(4). In the present study, we aimed to identify the properties of astroglial P2X7R in EAE and to identify mechanisms responsible for astrocyte activation in the presence of CNS-IICs (CD4+T cells). In this respect, spinal cords from rats at the peak of EAE and age-matched healthy controls were isolated and protein expression of P2X7R and connexin-43 (Cx-43) were investigated. P2X7R protein expression was decreased in the lumbar spinal cord, while Cx-43 did not change. Next, we found that P2X7R and Cx-43 proteins interact in the lumbar spinal cord since both the monomer and the dimer Cx-43 co-immunoprecipitate with P2X7R. Even though the colocalization of P2X7R and Cx-43 was decreased in EAE compared to the control, the analysis of the distribution of astroglial P2X7R and Cx-43 and their colocalization in the radius of 20 μm from the infiltrated CD4+T cell center showed that astroglial P2X7R and Cx-43 are specifically associated and concentrated in the proximity of CNS-IICs in the EAE spinal cord. Subsequently, to achieve an unambiguous analysis of astrocyte-immune cell interaction, we monitored Ca2+dynamics in Fluo-4 labeled cultured naïve astrocytes following brief bath-application of CNS-IICs isolated and purified from spinal cords of EAE rats. Our data suggest that astroglial αvβ3-integrin acted upstream of P2X7R activation and is likely involved in establishing initial contact of astrocytes with CNS-IICs since astrocytic αvβ3-integrin block reduced the astrocytic Ca2+response to CNS-IIC application. Furthermore, astrocytes challenged with CGP31157 (blocker of mNCLX and HCX) exhibited a prolonged intracellular Ca2+elevation and higher ATP release after brief exposure to CNS-IICs, indicating a regulatory function of mitochondria on this intracellular astrocyte Ca2+response. Collectively these data describing integrin-relevant cellular mechanisms of astroglial P2X7R activation could help to expand integrin-inhibiting therapeutic approaches currently in use for MS treatment toward control ofastrocyte purine-based interaction with immune cells.kategorija M3
The influence of spark plasma sintering temperature on the properties of Sb-doped barium stannate ceramics
Get PDFBarium-stannate (BaSnO3, BSO) is a member of the perovskite-type alkaline
earth stannates ASnO3 (A = Ca, Sr, Ba) with an ideal cubic crystal structure (space
group: ). Doping with antimony (Sb5+) can change this wide band-gap
semiconductor (Eg = 3.1-3.4 eV) into an n-type semiconductor with high electrical
conductivity at room temperature. The major drawbacks in the BSO-based ceramics
synthesis are phase composition and low density of final ceramic materials. These
problems could be solved using spark plasma sintering (SPS), a current and
pressure-assisted technique, which enables the preparation of dense ceramics at
significantly lower temperatures and for a shorter time.
To investigate the influence of spark plasma sintering temperature on the
structural, microstructural and electrical properties of BaSn1-xSbxO3 (BSSO, x =
0.00; 0,04; 0.06; 0.08; and 0.10) ceramics samples, BSSO powders were spark
plasma sintered at 1100 °C, 1200 °C and 1250 °C for 5 min.
X-ray diffraction (XRD) analysis confirmed that all ceramic samples sintered at
1100 °C crystallized in a single-phased cubic BSO structure. Their relative densities
were in the range of 72–82% ρt. Sintering at 1200 °C increased the samples’ relative
densities to 79–96% ρt, but also induced the formation of a barium-rich secondary
phase, Ba2SnO4. Rising the sintering temperature further to 1250 °C induced the
melting of all samples except BaSn0.92Sb0.08O3. Field emission scanning electron
microscopy (FE-SEM) revealed that doping with antimony decreased the grain sizes
in BSSO samples sintered at 1100 °C and 1200 °C up to the concentration x = 0.08.
Electrical measurements revealed the typical semiconductor behavior of the
undoped samples, showing nonlinear current-voltage characteristic and the existence
of one semicircle in their impedance spectra, characteristic for materials with double
Schottky barrier at the grain boundaries. However, samples with higher dopant
concentrations (x = 0.08 and 0.10) showed significantly lower electrical resistivity
and linear current-voltage characteristic. The lowest and almost constant value of
electrical resistivity in the temperature range of 25–150 °C, and complete loss of the
semicircle in its impedance spectrum revealed the metallic-like behavior of sample
BaSn0.92Sb0.08O3 sintered at 1200 °C
Quantum sensors for gas mixture detection
Get PDFNumerous methods have been utilized for molecular detection, including optical, calorimetric, acoustic, and techniques based on changes in electrical properties, such as metal oxide semiconductor sensors [1,2]. Recent research endeavors have led to a significant rise in sensitivity, detecting parts per billion (ppb) [3], but the challenges of selectivity and cross-sensing remain crucial areas of investigation. Developing a gas sensor with high selectivity to efficiently analyze multi-gas mixtures would be of great significance, with potential applications in various fields such as technology, environmental control, biology, and medicine.
Quantum sensors are a promising new technology for the detection of gas mixtures. They offer a number of advantages over traditional methods, including high sensitivity, selectivity, and response time. In the presentation, we propose a new method based on the resonant interaction of dipole molecules with ac fields, in the presence of a dc electric and magnetic field that creates Zeeman and Stark splitting of molecular levels specific to certain molecules, ensuring selectivity [4].
In this talk, we present some preliminary experimental results obtained for the molecule NO on the use of quantum sensors for the detection of gas mixtures. Our results demonstrate the potential of quantum sensors for a variety of applications in gas sensing. We believe that quantum sensors have the potential to revolutionize the field of gas sensing.
1. X. Liu, et al. Sensors (Basel), 12 (2012) 9635–9665.
2. S. Lakkis, R. Younes, Y. Alayli, M. Sawan, Sensor Review, 34 (2014) 24–35.
3. J.-H. Lee, J.-Y. Kim, J.-H. Kim, S. S. Kim, Sensors (Basel), 19 (2019) 726.
4. Z. Branković, Y. Rostovtsev, Sci. Rep., 10 (2020) 1537
Effects of thinning on stand structure and increment of crop trees of silver lime (Tilia tomentosa Moench) in the area of National park ,,Fruška Gora''
Get PDFU okviru ophodnje jednodobnih sastojina, period nege traje najduže, a naročito njegov deo u kojem se primenjuju prorede. Efekti različitih uzgojnih strategija nege sastojina mogu se sagledati samo na osnovu dugoročnih istraživanja na trajnim i komparativnim oglednim površinama. U zavisnosti od godine osnivanja oglednih površina, u tezi je istraživan 25 ili 26-godišnji uticaj dva tretmana proređivanja izdanačkih sastojina bele lipe različitih starosti na području Fruške gore. Prvi tretman je selektivna proreda, usmerena na stabla budućnosti koja su izdvojena 1993/94. godine na trajnim oglednim površinama (tretman E), a drugi je niska proreda na komparativnim, novopodignutim oglednim površinama 2019. godine (tretman P) u istim sastojinama. Istraživan je uticaj sprovedenih tretmana proreda na strukturu sastojina i izdvojenih uporedivih kolektiva stabala — stabala budućnosti na tretmanu E i uporedivih stabala na tretmanu P, izdvojenih po istim kriterijumima kao i stabla budućnosti na tretmanu E, ali 25–26 godina kasnije. Istraživanja su sprovedena u sastojinama starosti 52, 69 i 86 godina na kraju 2019. godine. Na oglednim površinama izvršen je premer prečnika i visina stabala, ocenjivanje stabala po biološkom položaju, stepenu stešnjenosti krošnje i kvalitetu debla, i izvršeno je njihovo kartiranje. Na nivou stabala budućnosti i uporedivih stabala izvršen je premer elemenata vertikalne i horizontalne izgrađenosti krošnji i uzimani su izvrci Presrelovim svrdlom kako bi se utvrdili elementi debljinskog i temeljničnog prirasta stabala u istom posmatranom periodu primene različitih tretmana proreda.
Za posmatrani period, sastojine negovane selektivnom proredom, primarno usmerenom na stabla budućnosti, karakteriše manji broj stabala, manja ukupna temeljnica i zapremina, veća horizontalna i vertikalna strukturna varijabilnost i znatno veće učešće stabala u okviru istog broja uporedivih kolektiva sa prečnikom većim od 35,0 cm bez kore (što je osnovni kriterijum za furnirski trupac) u odnosu na sastojine negovane niskom proredom. Stabla budućnosti karakterišu manje vrednosti stepena vitkosti i pravilnije razvijene krošnje u odnosu na uporedivi kolektiv stabala pod tretmanom niske prorede. U istraživanom periodu u sastojinama različitih starosti, reakcija debljinskog i temeljničnog prirasta je značajno veća kod stabala budućnosti negovanih selektivnom proredom u odnosu na uporedivi kolektiv stabala negovanih niskom proredom. Međutim, kod početka primene selektivne prorede u sastojinama starosti 44 i 61 godinu zabeležen je trend opadanja debljinskog prirasta u odnosu na starost 26 godina. Time je definisana okvirna starosna granica sastojina do koje je izražena prirasna reakcija stabala na primenu selektivne prorede. Iz razloga većih prečnika i većeg učešća zapremine stabala budućnosti u tretmanu E, ciljnog broja 150 stabala po hektaru u oba tretmana, njihove slabije prirasne reakcije posle 44. godine starosti, a uz jaku prirasnu reakciju u 26. godini, potvrđena je mogućnost korišćenja izražene prirasne reakcije stabala lipe, uz primenu selektivne prorede u sastojinama mlađim od 44 godine. Potvrđene su mogućnosti odgajivanja bele lipe sa većim prečnicima u periodu planske ophodnje uz primenu selektivne prorede, za razliku od uobičajene niske prorede, čime potvrđujemo mogućnosti ostvarivanja različitih funkcija šuma u nacionalnom parku kod različito formiranih sastojina lipe pod uticajem proreda.Within a rotation period, tending takes the longest in even-aged stands, especially the part that involves thinning. The effects of different maintenance strategies can only be discerned on the basis of long-term studies on permanent and comparative plots. In this work, the influence of two thinning treatments over a period of 25–26 years in coppice silver lime stands of different ages in the Fruška Gora area was studied. The first treatment is a selective thinning targeting elite trees selected in 1993 and 1994 on permanent sampling plots (treatment type E). The second treatment is thinning from below on comparable, newly established plots in 2019 (treatment P) in the same stands. The effects of treatments on stand structure and selective tree collectives was investigated on treatment E (elite trees) and comparison trees on treatment P that were selected using the same criteria as the elite trees, but 25–26 years later. Surveys were conducted at ages 52, 69, and 86 years at the end of 2019. An inventory of diameters and heights was conducted at the sample plots, which included an assessment of trees by social class, crown insulation, and stem quality. All trees were mapped. A crown inventory was conducted at the elite and comparison tree levels, which included vertical and horizontal crown development parameters. The two groups of trees were also drilled through with an increment borer (Pressler) to determine the diameter and basal area increment of the trees over the 25–26 year period following the application of various thinning methods.
In the 25–26 year period studied, stands where selective thinning was conducted, primarily targeting elite trees, were characterized by a lower number of trees, lower total basal area and volume, and more pronounced vertical and horizontal structure. In addition, a significantly higher number of trees with a mean breast height diameter of 35.0 cm without bark (the main criterion for veneer lumber) was found compared to the comparison trees in the thinning from below. The elite trees are characterized by lower values of the slenderness coefficient and more regularly developed crowns compared to the trees in thinning from below. In the studied period of 25–26 years, in the stands of different ages, the growth response of the trees, expressed in diameter and basal area increment, was significantly higher in the elite trees than in the comparable trees in the thinning from below. However, when selective thinning is initiated in stands at 44 and 61 years of age, there is a trend toward a decrease in growth response compared to initiation at 26 years of age. Therefore, a general age limit for the application of selective thinning was established. Within the target of 150 trees per hectare, the proportion of elite trees with a breast height diameter greater than 35.0 cm without bark was higher in the selective thinning treatment than in the thinning from below treatment. This, together with the decreasing growth response after 44 years and a strong response in the 26-year-old stand, confirms that the growth response of silver lime can be exploited by intensive selective thinning in stands younger than 44 years. It is confirmed that silver lime with higher breast height diameters can be grown in the planned rotation by selective thinning, which is not the case with the commonly used thinning method from below. Therefore, the high quality silver lime stands already established can be used for a number of other forest functions in the National Park
Derivatives in Advanced Oxidation Processes: Experimental and Kinetic DFT Stud
Get PDFCoumarins represent a broad class of compounds with pronounced pharmacological properties and therapeutic potential. The pursuit of the commercialization of these compounds requires the establishment of controlled and highly efficient degradation processes, such as advanced oxidation processes (AOPs). Application of this methodology necessitates a comprehensive understanding of the degradation mechanisms of these compounds. For this reason, possible reaction routes between HO• and recently synthesized aminophenol 4,7-dihydroxycoumarin derivatives, as model systems, were examined using electron paramagnetic resonance (EPR) spectroscopy and a quantum mechanical approach (a QM-ORSA methodology) based on density functional theory (DFT). The EPR results indicated that all compounds had significantly reduced amounts of HO• radicals present in the reaction system under physiological conditions. The kinetic DFT study showed that all investigated compounds reacted with HO• via HAT/PCET and SPLET mechanisms. The estimated overall rate constants (koverall) correlated with the EPR results satisfactorily. Unlike HO• radicals, the newly formed radicals did not show (or showed negligible) activity towards biomolecule models representing biological targets. Inactivation of the formed radical species through the synergistic action of O2/NOx or the subsequent reaction with HO• was thermodynamically favored. The ecotoxicity assessment of the starting compounds and oxidation products, formed in multistage reactions with O2/NOx and HO•, indicated that the formed products showed lower acute and chronic toxicity effects on aquatic organisms than the starting compounds, which is a prerequisite for the application of AOPs procedures in the degradation of compounds
In Vitro and In Vivo Anthelmintic Efficacy of Peppermint (Mentha x piperita L.) Essential Oil against Gastrointestinal Nematodes of Sheep
Get PDFNowadays, the exclusive use of commercial anthelmintics for the treatment of gastrointestinal nematode infections in ruminants is less sustainable due to anthelmintic resistance, as well as the problem of drug residues in animal products and the environment. Therefore, an integrated therapeutic approach is needed, including the search for alternatives to synthetic anthelmintic drugs. The aim of this study was to evaluate the possibility of using the essential oil of peppermint (Mentha x piperita L.) in the control of gastrointestinal nematodes in sheep. For this purpose, the in vitro and in vivo anthelmintic efficacy of this oil and the toxic effects on the hosts were examined. In the in vitro egg hatch test, ovicidal activity varied from 21.0–90.3% depending on the concentration of essential oil used (0.0125, 0.025, 0.049, 0.195, 0.781, 3.125, 12.5, and 50 mg/mL). To some extent, anthelmintic efficacy was confirmed in the in vivo fecal egg count reduction test at a mean dose of 150 mg/kg, with an average reduction of nematode eggs of 26.9 and 46.0% at Days 7 and 14 after treatment, respectively. Furthermore, no toxic effects of applied oil were observed on sheep behavior, kidney, or liver function. The main compounds identified by gas chromatography–mass spectrometry analyzes were menthol (32.6%), menthone (22.0%), menthyl-acetate (10.0%), and isomenthone (9.39%). Due to their complex chemical compositions, numerous bioactive ingredients, and natural origin, herbal formulations represent a potentially valuable alternative for the control of gastrointestinal nematodes in sheep. In this context, the results of the present study showed that peppermint essential oil is one of the promising candidates. Further studies should be performed to collect more data on the safety profile of M. piperita EO in treated animals to find the most appropriate formulation for use in field conditions and to test it against resistant gastrointestinal nematode populations
Flexible composite films with enhanced piezoelectric properties for energy harvesting and wireless ultrasound-powered technology
Get PDFIn the last years, ultrasound energy harvesting has emerged as the most promising technique for wireless power supply of implanted medical devices. These devices require flexible piezoelectric materials with high piezoelectric response in the ultrasonic range. Here we report on bio-compatible NBT-BT/PVDF flexible composites, with variable filler content up to 50 vol%, prepared by a properly designed and optimized process, which incorporates in a complex connectivity pattern fully sintered NBT-BT crystalline powders in a PVDF matrix. The dielectric constant of the flexible composites increased from 10 of pure PVDF polymer to 110 of composite films with 50 vol% NBT-BT content, while the high frequency piezoelectric d33 constant increased from 0.2 pC/N to 33 pC/N for the same samples. The composite with 50 vol% NBT-BT exhibits the figure of merit for the harvested ultrasound energy d33g33 ≅ 1.54 × 10−12 m3/J, which is comparable to the figure of merit for the NBT-BT piezoelectric ceramic (1.8 × 10−12 m3/J) and higher than other reported results for random composites. Based on these results, this study provides an easy method to fabricate random flexible piezoelectric composites with enhanced high frequency piezoelectric response and high energy density harvested from an ultrasound source
BIOCTA: Novel approach to biocontrol of recently described plant tumorogenic Rhizobium spp. using autochthonous microbial solutions
Get PDFIntroduction: A novel group of Rhizobiumspp. strains belonging to the “tumorigenes” clade has recently been described on blackberry in Serbia and Germany and on rhododendron in Germany. The BIOCTA project aimed to characterize efficient plant-associated bacterial strains for biocontrol of crown gall, thus providing an environmentally friendly alternative to pesticides that would contribute to the development of sustainable agriculture.
Methods: Antagonistic potential of 37 biocontrol strains against two R. tumorigenes strains 932 and 1078 and Rhizobium sp. strain rho-6.2 was evaluated in vitro using the “well diffusion” method, as well as in vivo on tomato plants, using two inoculation strategies (co-inoculation and preventive). DNA metabarcoding approach was used to analyze the phytobiome of treated and non-treated tomato plants.
Results: Based on the determined in vitro antagonistic potential, seven strains – Bacillus spp. (B. amyloliquefaciens ID084 and GT28.3, B. velezensis X5-2, and B. subtilis GD1), Pseudomonas sp. (R-6.10 and R11-20) and Agrobacterium rosae rho-6.1 were selected for further in vivo experiments. Of all tested strains/treatments, two Pseudomonas strains were the most efficient, showing up to 92.86%efficacy in suppressing tumors caused by Rhizobiumsp. strain rho-6.2 when applied in a co-inoculation strategy. Based on the DNA metabarcoding analysis, genera Pseudolabrys and Asanoa prevailed in the co-inoculation strategy, while Allorhizobium-Neorhizobium-Pararhizobium-Rhizobium prevailed in positive control.
Conclusion: Crown gall tumors have shown to be a valuable source of antagonistic isolates.
Pseudomonas strains R-6.10 and R11-20 could be proposed for the efferent control of crown gall caused by newly described Rhizobium spp. strains in nurseries
Tunnel junction sensing of TATP explosive at the single-molecule level
No full textTriacetone triperoxide (TATP) is a highly potent homemade explosive commonly used in terrorist
attacks. Its detection poses a significant challenge due to its volatility, and the lack of portability of
current sensing techniques. To address this issue, we propose a novel approach based on singlemolecule TATP detection in the air using a device where tunneling current in N-terminated carbonnanotubes nanogaps is measured. By employing the density functional theory combined with the nonequilibrium Green’s function method, we show that current of tens of nanoamperes passes through
TATP trapped in the nanogap, with a discrimination ratio of several orders of magnitude even against
prevalent indoor volatile organic compounds (VOCs). This high tunneling current through TATP’s highest
occupied molecular orbital (HOMO) is facilitated by the strong electric field generated by N–C polar
bonds at the electrode ends and by the hybridization between TATP and the electrodes, driven by oxygen atoms within the probed molecule. The application of the same principle is discussed for graphene
nanogaps and break-junctions
Photocatalytic Activity of the V2O5 Catalyst toward Selected Pharmaceuticals and Their Mixture: Influence of the Molecular Structure on the Efficiency of the Process
No full textDue to the inability of conventional wastewater treatment procedures to remove organic
pharmaceutical pollutants, active pharmaceutical components remain in wastewater and even reach
tap water. In terms of pharmaceutical pollutants, the scientific community focuses on -blockers due
to their extensive (over)usage and moderately high solubility. In this study, the photocatalytic activity
of V2O5 was investigated through the degradation of nadolol (NAD), pindolol (PIN), metoprolol
(MET), and their mixture under ultraviolet (UV) irradiation in water. For the preparation of V2O5,
facile hydrothermal synthesis was used. The structural, morphological, and surface properties
and purity of synthesized V2O5 powder were investigated by scanning electron microscopy (SEM),
X-ray, and Raman spectroscopy. SEM micrographs showed hexagonal-shaped platelets with welldefined
morphology of materials with diameters in the range of 10–65 μm and thickness of around
a few microns. X-ray diffraction identified only one crystalline phase in the sample. The Raman
scattering measurements taken on the catalyst confirmed the result of XRPD. Degradation kinetics
were monitored by ultra-fast liquid chromatography with diode array detection. The results showed
that in individual solutions, photocatalytic degradation of MET and NAD was relatively insignificant
(<10%). However, in the PIN case, the degradation was significant (64%). In the mixture, the
photodegradation efficiency of MET and NAD slightly increased (15% and 13%). Conversely, it
reduced the PIN to the still satisfactory value of 40%. Computational analysis based on molecular and
periodic density functional theory calculations was used to complement our experimental findings.
Calculations of the average local ionization energy indicate that the PIN is the most reactive of all
three considered molecules in terms of removing an electron from it