Details about molecular membrane dynamics in living cells, such as lipid-protein interactions, are often hidden from the observer because of the limited spatial resolution of conventional far-field ...optical microscopy. The superior spatial resolution of stimulated emission depletion (STED) nanoscopy can provide new insights into this process. The application of fluorescence correlation spectroscopy (FCS) in focal spots continuously tuned down to 30 nm in diameter distinguishes between free and anomalous molecular diffusion due to, for example, transient binding of lipids to other membrane constituents, such as lipids and proteins. We compared STED-FCS data recorded on various fluorescent lipid analogs in the plasma membrane of living mammalian cells. Our results demonstrate details about the observed transient formation of molecular complexes. The diffusion characteristics of phosphoglycerolipids without hydroxyl-containing headgroups revealed weak interactions. The strongest interactions were observed with sphingolipid analogs, which showed cholesterol-assisted and cytoskeleton-dependent binding. The hydroxyl-containing headgroup of gangliosides, galactosylceramide, and phosphoinositol assisted binding, but in a much less cholesterol- and cytoskeleton-dependent manner. The observed anomalous diffusion indicates lipid-specific transient hydrogen bonding to other membrane molecules, such as proteins, and points to a distinct connectivity of the various lipids to other membrane constituents. This strong interaction is different from that responsible for forming cholesterol-dependent, liquid-ordered domains in model membranes.
DANSS is a highly segmented 1 m3 plastic scintillator detector. Its 2500 one meter long scintillator strips have a Gd-loaded reflective cover. The DANSS detector is placed under an industrial 3.1 ...GWth reactor of the Kalinin Nuclear Power Plant 350 km NW from Moscow. The distance to the core is varied on-line from 10.7 m to 12.7 m. The reactor building provides about 50 m water-equivalent shielding against the cosmic background. DANSS detects almost 5000 ν˜e per day at the closest position with the cosmic background less than 3%. The inverse beta decay process is used to detect ν˜e. Sterile neutrinos are searched for assuming the 4ν model (3 active and 1 sterile ν). The exclusion area in the Δm142,sin22θ14 plane is obtained using a ratio of positron energy spectra collected at different distances. Therefore results do not depend on the shape and normalization of the reactor ν˜e spectrum, as well as on the detector efficiency. Results are based on 966 thousand antineutrino events collected at three different distances from the reactor core. The excluded area covers a wide range of the sterile neutrino parameters up to sin22θ14<0.01 in the most sensitive region.
•1,3-dichorobenzene is an occupationally relevant noxious agent in silicone rubber industry.•First method to quantify urinary mercapturates of 1,3-dichlorobenzene using online-SPE LC-MS/MS.•Authentic ...mercapturate standards and labelled analogues were self-synthesized.•The method is fully automated, precise, sensitive and accurate.•Post-shift urine of exposed workers shows that mercapturates are suitable biomarkers.
1,3-dichlorobenzene (1,3-DCB) is an aromatic solvent that might be formed during thermal decomposition of bis(2,4-dichlorobenzoyl)peroxide used as initiator in silicone rubber production with many workers exposed worldwide. During metabolism of 1,3-DCB, two isomeric mercapturic acids can be formed from ring oxidation of 1,3-DCB in the liver, namely 2,4-dichlorophenylmercapturic acid (24CPhMA) and 3,5-dichlorophenylmercapturic acid (35CPhMA). These urinary mercapturic acids might serve as biomarkers of the toxicologically relevant absorbed dose of 1,3-DCB and have not been determined so far. Thus, we were aimed to develop an analytical method for quantification of these biomarkers.
Authentic standards of both mercapturic acids as well as deuterium-labelled analogues were self-synthesized. A method for the quantification of both CPhMAs in human urine using online-SPE LC/MS/MS was developed and validated with an LOQ of 0.1 ng mL−1 for both CPhMAs. The analytes were extracted from urine by online-SPE on a restricted access material phase, transferred to the analytical column and quantified by tandem mass spectrometry. Interday (n = 6) and Intraday (n = 10) precision for both CPhMAs ranged from 1.7 to 4.3 % with accuracies between 99.4 and 109.9 % at concentrations of 0.6 and 3 ng mL−1. We applied the method on post-shift urine samples of 16 workers of the silicone rubber industry with occupational exposure to 1,3-DCB. Both CPhMAs were above LOQ in 15 of 16 urine samples with median levels (range) for 24CPhMA and 35CPhMA of 1.64 ng mL−1 (<0.1 – 8.2 ng mL−1) and 3.98 ng mL−1 (0.36 – 24.1 ng mL−1), respectively.
This is the first report on specific urinary mercapturic acids of 1,3-DCB in humans. Our results show that ring oxidation of 1,3-DCB is considered to be a toxicologically relevant metabolic pathway in humans. This might improve risk assessment of 1,3-DCB-emissions in silicone rubber industry.
STARE2: Detecting Fast Radio Bursts in the Milky Way Bochenek, Christopher D.; McKenna, Daniel L.; Belov, Konstantin V. ...
Publications of the Astronomical Society of the Pacific,
03/2020, Letnik:
132, Številka:
1009
Journal Article
Recenzirano
Odprti dostop
There are several unexplored regions of the short-duration radio transient phase space. One such unexplored region is the luminosity gap between giant pulses (from pulsars) and cosmologically located ...fast radio bursts (FRBs). The Survey for Transient Astronomical Radio Emission 2 (STARE2) is a search for such transients out to 7 Mpc. STARE2 has a field of view of 3.6 steradians and is sensitive to 1 millisecond transients above ∼300 kJy. With a two-station system we have detected and localized a solar burst, demonstrating that the pilot system is capable of detecting short duration radio transients. We found no convincing non-solar transients with duration between 65 s and 34 ms in 200 days of observing, limiting with 95% confidence the all-sky rate of transients above ∼300 kJy to <40 sky−1 yr−1. If the luminosity function of FRBs could be extrapolated down to 300 kJy for a distance of 10 kpc, then one would expect the rate to be ∼2 sky−1 yr−1.
The germplasm collection of 87 wheat-wheatgrass hybrids developed in Tsitisin Main Botanical Garden (Russia, Moscow) was evaluated for resistance to pre-harvest sprouting (PHS) by spike sprouting ...(SS) and germination index (GI) assays as well as for spike and grain features. The PHS resistance variation and haplotype polymorphism of the wheatgrass ThVp-1 and wheat TaVp-1B genes orthologues of Vp-1 was revealed in the studied collection. Four haplotypes of ThVp-1 were revealed: ThVp-1a (41% of the entries), ThVp-1b (13%), ThVp-1c (29%), and ThVp-1d (15%). The association between the allelic state of ThVp-1 and PHS resistance in the wheat-wheatgrass hybrids was shown: haplotype ThVp-1d of the wheatgrass Vp-1 gene is significantly associated with reduced PHS in the wheat-wheatgrass hybrids (mean SS 0.33, mean GI 0.64). The resistant entries may be perspective as a source of PHS resistance in the development of commercial cultivars of perennial wheat.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Germany’s transition to a climate-neutral economy, the main parameters of which were determined by the European Green Exchange Rate (December 2019) and clarified in the updated Law on Climate ...Protection of Germany (June 2021) and the EU Fit-for-55 program (July 2021), leads to the abandonment of the use of primary energy sources, including their importation from Russia. The energy transformation of the German market economy presumed a gradual restructuring of the existing model of German–Russian cooperation in the energy sector, including its transfer to priority cooperation in the field of energy efficiency and renewable energy sources. Brussels and Berlin responded to the special military operation of the Russian Federation on the territory of Ukraine with large-scale economic and political sanctions, which included significant restrictions on the import of Russian coal and oil. At the same time, the German federal authorities outlined the necessity to abandon Russian pipeline gas and petroleum products, as well as the deprivation of ownership of the two main players from the Russian Federation in the German oil and gas market—Gazprom and Rosneft. Their German partners have frozen participation in Russian projects. At the end of February, the certification of the Nord Stream-2 offshore gas pipeline was stopped. Interdepartmental state interaction and scientific and technical cooperation in the energy sector have been terminated. These events indicated the readiness of the government coalition in the short term to replace the previous model of energy cooperation, which has performed well for half a century, and to move to independence from Russian fossil resources and their derivatives. The author analyzes the reasons and content of the current measures taken by Berlin, as well as their medium- and long-term consequences for German–Russian cooperation.
The search for new forms of already known drug compounds is an urgent problem of high relevance as more potent drugs with fewer side effects are needed. The trifluoromethyl group in flufenamic acid ...renders its chemical structure differently from other fenamates. This modification is responsible for a large number of conformational polymorphs. Therefore, flufenamic acid is a promising structural modification of well-known drug molecules. An effective approach in this field is micronization, employing "green" supercritical fluid technologies. This research raises some key questions to be answered on how to control polymorphic forms during the micronization of drug compounds. The results presented in this work demonstrate the ability of two-dimensional nuclear Overhauser effect spectroscopy to determine conformational preferences of small molecular weight drug compounds in solutions and fluids, which can be used to predict the polymorphic form during the micronization. Quantitative analysis was carried out to identify the conformational preferences of flufenamic acid molecules in dimethyl sulfoxide-d6 medium at 25 °C and 0.1 MPa, and in mixed solvent medium containing supercritical carbon dioxide at 45 °C and 9 MPa. The data presented allows predictions of the flufenamic acid conformational preferences of poorly soluble drug compounds to obtain new micronized forms.
The study presents a thorough and detailed analysis of bicalutamide’s structural and conformational properties. Quantum chemical calculations were employed to explore the conformational properties of ...the molecule, identifying significant energy differences between conformers. Analysis revealed that hydrogen bonds stabilise the conformers, with notable variations in torsion angles. Conformers were classified into ‘closed’ and ‘open’ types based on the relative orientation of the cyclic fragments. NOE spectroscopy in different solvents (CDCl3 and DMSO-d6) was used to study the conformational preferences of the molecule. NOESY experiments provided the predominance of ‘closed’ conformers in non-polar solvents and a significant presence of ‘open’ conformers in polar solvents. The proportions of open conformers were 22.7 ± 3.7% in CDCl3 and 59.8 ± 6.2% in DMSO-d6, while closed conformers accounted for 77.3 ± 3.7% and 40.2 ± 6.2%, respectively. This comprehensive study underscores the solvent environment’s impact on its structural behaviour. The findings significantly contribute to a deeper understanding of conformational dynamics, stimulating further exploration in drug development.
An atmospheric correction algorithm is proposed for the reconstruction of the ground surface reflectance from the data of satellite measurements. A distinctive feature of the algorithm is that it ...takes into account the influence of the ground surface inhomogeneity on the adjacency effect and additional illumination of the ground surface by reflected radiation. These factors are important for the reconstruction of the reflectance of ground surface fragments with sharp reflectance changes and high atmospheric turbidity. The algorithm is based on Monte Carlo programs developed by the authors. To reduce the computing time, we have proposed some original criteria and approaches. To estimate the capabilities of the developed algorithm, its results have been validated by comparing with the results of the MOD09 algorithm for four MODIS bands and measurements for the Portugal surface fragment with coordinates 38.829 N, 8.791 W. Good agreement of the results obtained by the proposed algorithm with the surface measurements and the data obtained by the MOD09 algorithm demonstrates the efficiency of the proposed algorithm in the reconstruction of the ground surface reflectance.
Herein, we describe the nonlinear processes for the formation of thin films of the PbS-CdS system using chemical bath deposition with a gradual change in the cadmium nitrate content in the reaction ...mixture. The morphology of films was studied
via
scanning electron microscopy and atomic force microscopy. The mechanism for the formation of thin-film compounds can be considered as cluster-particle aggregation (diffusion-limited aggregation). X-ray diffraction confirmed the formation of single-phase layers of substitutional
B
1-type Cd
x
Pb
1−
x
S solid solutions (space group
Fm
3&cmb.macr;
m
) when the concentration of cadmium nitrate in the reaction bath increased up to Cd(NO
3
)
2
= 0.08 M. The maximum cadmium content in Cd
x
Pb
1−
x
S solid solutions was determined to be
x
= 0.094. At the concentration of Cd(NO
3
)
2
= 0.10 M, a two-phase film was formed, where the film consisted of crystallites of cubic Cd
x
Pb
1−
x
S with
x
= 0.071 (lower compared to the film obtained at Cd(NO
3
)
2
= 0.08 M) and fine-crystalline hexagonal
B
4-type Cd
1−
δ
S (space group
P
6
3
mc
). The texture of grains forming films was observed; where a predominant orientation with the (111) plane along substrate in PbS changed to the (200) plane in Cd
x
Pb
1−
x
S films, the portion of (200) oriented grains increased with an increase in cadmium nitrate content up to Cd(NO
3
)
2
= 0.08 M, and at 0.10 M of cadmium nitrate, a radical change in the type of texture to the (111) type occurred. The concentration Cd(NO
3
)
2
= 0.10 M is called the critical concentration, where under this condition, the deposition process occurs due to the excess Gibbs energy. The higher cadmium content
x
in films determined by the energy-dispersive X-ray analysis and Auger spectroscopy compared with that estimated from the crystal lattice parameter is associated with the presence of an additional amorphous CdS phase formed as a sublayer distributed in intercrystalline spaces and island formations. Optical studies showed a nonlinear change in the band gap (
E
g
) of obtained films from 0.53 to 0.76 eV, whereas at the critical cadmium salt concentration (0.10 M), two crystalline phases with
E
g
equal to 0.73 and 2.47 eV were observed.
Nonlinear change in composition, structure, and optical properties is shown for the films of supersaturated substitutional solid solutions Cd
x
Pb
1−
x
S (
x
≤ 0.094) during chemical bath deposition with adding cadmium nitrate.