Flux and Seasonality of Dissolved Organic Matter From the Northern Dvina (Severnaya Dvina) River, Russia

Pan‐Arctic riverine dissolved organic carbon (DOC) fluxes represent a major transfer of carbon from land‐to‐ocean, and past scaling estimates have been predominantly derived from the six major Arctic rivers. However, smaller watersheds are constrained to northern high‐latitude regions and, particularly with respect to the Eurasian Arctic, have received little attention. In this study, we evaluated the concentration of DOC and composition of dissolved organic matter (DOM) via optical parameters, biomarkers (lignin phenols), and ultrahigh resolution mass spectrometry in the Northern Dvina River (a midsized high‐latitude constrained river). Elevated DOC, lignin concentrations, and aromatic DOM indicators were observed throughout the year in comparison to the major Arctic rivers with seasonality exhibiting a clear spring freshet and also some years a secondary pulse in the autumn concurrent with the onset of freezing. Chromophoric DOM absorbance at a350 was strongly correlated to DOC and lignin across the hydrograph; however, the relationships did not fit previous models derived from the six major Arctic rivers. Updated DOC and lignin fluxes were derived for the pan‐Arctic watershed by scaling from the Northern Dvina resulting in increased DOC and lignin fluxes (50 Tg yr−1 and 216 Gg yr−1, respectively) compared to past estimates. This leads to a reduction in the residence time for terrestrial carbon in the Arctic Ocean (0.5 to 1.8 years). These findings suggest that constrained northern high‐latitude rivers are underrepresented in models of fluxes based from the six largest Arctic rivers with important ramifications for the export and fate of terrestrial carbon in the Arctic Ocean

Thermodynamically Important Contacts in Folding of Model Proteins

We introduce a quantity, the entropic susceptibility, that measures the thermodynamic importance-for the folding transition-of the contacts between amino acids in model proteins. Using this quantity, we find that only one equilibrium run of a computer simulation of a model protein is sufficient to select a subset of contacts that give rise to the peak in the specific heat observed at the folding transition. To illustrate the method, we identify thermodynamically important contacts in a model 46-mer. We show that only about 50% of all contacts present in the protein native state are responsible for the sharp peak in the specific heat at the folding transition temperature, while the remaining 50% of contacts do not affect the specific heat.Comment: 5 pages, 5 figures; to be published in PR

The use of LLIF technology in adult patients with degenerative scoliosis: retrospective cohort analysis and literature review

Introduction Incidence of adult degenerative scoliosis (ADS) among individuals over 50 years old reaches 68%. Surgical interventions aimed at correcting the spinal deformity in patients of the older age group are accompanied by a high risk of complications. The use of LLIF is associated with lower complications as compared with open anterior or posterior fusion. Materials and methods Seventy-one patients with ADS (13 men, 58 women) were operated at the Federal Neurosurgical Center. Their average age was 60.4/60 (average/median) [55;64.5] (1: 3 quartile) years. The follow-up was from 12 to 18 months. X-ray study, SCT, MRI of the lumbar spine were used. Questionnaire surveys were conducted using the visual analog pain scale (VAS), Oswestry Disability Index (ODI) and the Short Form-36 (SF-36). Deformity correction was estimated in the frontal plane with Cobb’s method. Scoliosis was classified according to SRS-Schwab classification. Parameters of sagittal balance were estimated: PI (Pelvic incidence), SS (Sacral slope), PT (Pelvic tilt), LL (Lumbar lordosis). SVA, PT and PILL (PI minus LL) were defined adjusted for the age. Results Back pain according to VAS relieved from 6.1/6 [4;8] to 2.2/2 [2;3] points (p < 0.001) and was statistically significant at 12 months after the surgery. Leg pain according to VAS decreased from 5.4/5 [4;8] to 2.1/2 [1;3] points (p < 0.001) and was statistically significant at 12 months after the surgery. Functional adaptation according to ODI improved from 51.2/52.2 [38.6;64.1] to 31.8/33.3 [26.1;35.9] (p < 0.001). According to SF36, PH before the surgery was 25.7/24.3 [21.8;28.9] on average and at 12 months after the surgery - 38.7/38.7 [35.4;41.2] (p < 0.001). SF-36 MH before surgery was 27.1/26.3 [21.8;31.4] on average and 12 months later – 41.3/40.6 [36.5;43.7] (p < 0.001). PT before the surgery was 23.3/22° [17.5;28], 12 months later it was 17.9/17° [15;20] (p < 0.001). PI-LL was 11.5/10 ° [4;17.5], 12 months later – 8.4/8 ° [5.5;11.5] (p = 0.11). Transient paresis of femur flexors on the ipsilateral side was observed in five (7 %) cases; transient hyposthesia on the anterior thigh surface occurred in eight (11.2 %) cases. There were two cases of medial malposition (0.4 %) of pedicle screws (474 screws), pseudoarthrosis at two levels (1.2 %) (Grade 4 Bridwell) out of 166 levels performed, and seven (4.2 %) cases of damage to cortical endplates. Conclusion Restoration of local sagittal balance in ADS patients by short-segment fixation using LLIF technology leads to a statistically significant improvement in the quality of life and increases functional adaptation. Few early and late postoperative complications, less intraoperative blood loss and shorter hospital stay make LLIF in combination with MIS transpedicular fixation a method of choice in determining the surgical tactics for ADS in elderly and old age patients

Unitary and Non-Unitary Matrices as a Source of Different Bases of Operators Acting on Hilbert Spaces

Columns of d^2 x N matrices are shown to create different sets of N operators acting on $d$-dimensional Hilbert space. This construction corresponds to a formalism of the star-product of operator symbols. The known bases are shown to be partial cases of generic formulas derived by using d^2 x N matrices as a source for constructing arbitrary bases. The known examples of the SIC-POVM, MUBs, and the phase-space description of qubit states are considered from the viewpoint of the developed unified approach. Star-product schemes are classified with respect to associated d^2 x N matrices. In particular, unitary matrices correspond to self-dual schemes. Such self-dual star-product schemes are shown to be determined by dequantizers which do not form POVM.Comment: 12 pages, 1 figure, 1 table, to appear in Journal of Russian Laser Researc

Ultra high energy cosmic ray detector KLYPVE on board the Russian Segment of the ISS

International audienceModified KLYPVE is a novel fluorescence detector of ultra high energy cosmic rays (UHECRs, energies & 50 EeV) to be installed on the Russian Segment of the International Space Station. The main goal of the experiment is to register arrival directions and energies of UHECRs but it will be able to register other transient events in the atmosphere as well. The main component of KLYPVE is a segmented two component optical system with a large entrance pupil and a wide field of view, which provides annual exposure approximately twice that of the Pierre Auger Observatory. The project is actively developed by a working group of the JEM-EUSO Collaboration led by Skobeltsyn Institute of Nuclear Physics at Moscow State University (Russia). The current status of KLYPVE with a focus on its scientific tasks, technical parameters and instruments is presented

Diurnal variations of trace metals and heterotrophic bacterioplankton concentration in a small boreal lake of the White Sea basin

This work represents a concerted effort aimed at understanding the microbiological and chemical evolution of a small boreal lake during the diurnal cycle of photosynthesis. We studied diurnal variation of ∼40 dissolved macro- and trace elements, organic carbon and bacterial population dynamics in the surface and bottom water layer of the shallow Vilno Lake in the White Sea basin. Four-days continuous measurements with 6 h sampling steps both at the surface (0.5 m) and on the bottom (4.0 m depth) during no-bloom periods revealed constant concentrations (within ±20–30%) of all major elements (Na, Mg, Si, K, Ca), organic and inorganic carbon and most trace elements (B, V, Cr, Fe, Cu, Ga, As, Rb, Sr, Y, Zr, Sb, Cs, Ba, all REEs, Hf, Pb, Th, U). At the same time, the concentration of some biologically important trace metals (Mo, Mn, Co, Cd) was subjected to variations partially reflecting the change of bacterioplankton concentration. This work enables two types of element behavior to be distinguished during photosynthesis in the water column – constant concentration and sinusoidal variations – depending on their speciation in solution and their affinity to aquatic microorganisms

Is carbonic anhydrase activity of photosystem II required for its maximum electron transport rate?

It is known, that the multi-subunit complex of photosystem II (PSII) and some of its single proteins exhibit carbonic anhydrase activity. Previously, we have shown that PSII depletion of HCO3-/CO2 as well as the suppression of carbonic anhydrase activity of PSII by a known inhibitor of α‑carbonic anhydrases, acetazolamide (AZM), was accompanied by a decrease of electron transport rate on the PSII donor side. It was concluded that carbonic anhydrase activity was required for maximum photosynthetic activity of PSII but it was not excluded that AZM may have two independent mechanisms of action on PSII: specific and nonspecific. To investigate directly the specific influence of carbonic anhydrase inhibition on the photosynthetic activity in PSII we used another known inhibitor of α‑carbonic anhydrase, trifluoromethanesulfonamide (TFMSA), which molecular structure and physicochemical properties are quite different from those of AZM. In this work, we show for the first time that TFMSA inhibits PSII carbonic anhydrase activity and decreases rates of both the photo-induced changes of chlorophyll fluorescence yield and the photosynthetic oxygen evolution. The inhibitory effect of TFMSA on PSII photosynthetic activity was revealed only in the medium depleted of HCO3-/CO2. Addition of exogenous HCO3- or PSII electron donors led to disappearance of the TFMSA inhibitory effect on the electron transport in PSII, indicating that TFMSA inhibition site was located on the PSII donor side. These results show the specificity of TFMSA action on carbonic anhydrase and photosynthetic activities of PSII. In this work, we discuss the necessity of carbonic anhydrase activity for the maximum effectiveness of electron transport on the donor side of PSII

Radiation-induced preparation of metal nanostructures in coatings of interpolyelectrolyte complexes

Copper, silver and gold nanoparticles were obtained by reduction of metal ions under X-ray irradiation of “layer-by-layer” (LbL) coatings in a water-alcohol medium. The precursors for metal polymer composites (metallopolymer complexes) were prepared by sorption of metal ions in polyethyleneimine - poly (styrenesulfonic acid) and polyethyleneimine - poly (acrylic acid) coatings deposited on cotton fibers. EPR spectroscopy was use to characterize the complexation of metal ions in coatings with different chemical structure and variable number of polyanion-polycation layers. The effect of coating structure and thickness on the size and stability of nanoparticles was studied using TEM and microdiffraction measurements. Antibacterial activity was found for composites containing silver nanoparticles.The reported study was funded by RFBR according to the research project № 18-33-01155

Microbiota of Cow’s Milk with Udder Pathologies

Mastitis is the most common disease for cattle, causing great economic losses for the global dairy industry. Recent studies indicate the multi-agent and microbiome diversity of this disease. To understand the nature of mastitis and investigate the role of the microbiome in the development of pathologies in the udder of bovines, we performed NGS sequencing of the 16S rRNA gene of cow’s milk with pathologies of the udder. The obtained data show a significant increase in the Cutibacterium, Blautia, Clostridium sensu stricto 2, Staphylococcus, Streptococcus and Microbacterium genera for groups of cows with udder pathologies. Increasing relative abundance of the Staphylococcus and Streptococcus genera was associated with subclinical mastitis. Our data show that a relative increase in abundance of the Staphylococcus and Microbacterium genera may be an early sign of infection. We have shown, for the first time, an increase in the Colidextribacter, Paeniclostridium and Turicibacter genera in groups of cows with mastitis. These results expand our understanding of the role of the microbiome in the development of bovine mastitis