Evaluation of Suppressiveness of chernozem upon the intake of organic fertilizers under the conditions of a model experiment

The problem of maintaining the sanitary function of soils of agroecosystems is one of the main ones, since it determines the danger for reproduction of various types of microorganisms, including human and animal pathogens. Within the study, the authors assessed the number of bacteria (Salmonella enterica and Escherichia coli) in samples of chernozem with introduction of organic fertilizers. The dynamics of the number of Salmonella enterica shows that organic matter in soils contributes to a sharp decrease in their number at the initial stages of biological pollution, and in the long term it contributes to total loss. By the 60th day, Salmonella was found only in the control option of the experiment, but continuation of the experiment showed their total loss on the 80th day. Introduction of organic ameliorants into the chernozem samples led to a decrease in the number of E. coli by the 80th day, but their total loss was not noted.

Bioaccessibility of Antioxidants in Blackcurrant Juice After Treatment Using Supercritical Carbon Dioxide

Blackcurrant juice (Ribes nigrum L.) was subjected to supercritical carbon dioxide (SCCD) at 10, 30 and 60 MPa for 10 min at 45°C as well as thermally treated at 45°C and 85°C for 10 min to determine the stability, antioxidant capacity (AC) and bioaccessibility (BAc) of vitamin C, total anthocyanins and their individual monomers. An in vitro gastrointestinal digestion model completed with dialysis was used to assess BAc. The use of SCCD at each of the pressures applied improved the stability of vitamin C, total anthocyanins, and AC before in vitro digestion. As a result of digestion, L-ascorbic acid was oxidized to L-dehydroascorbic acid, and finally, the total content of vitamin C, anthocyanins, and AC decreased. SCCD did not significantly improve the BAc of vitamin C and total anthocyanins. The highest BAc of vitamin C was noted in fresh juice (FJ) (40%) and after mild heat treatment at 45°C (T45) (46%). The highest BAc of total anthocyanins was also noted in the FJ (4.4%). The positive effect of the application of SCCD on the BAc of the delphinidin-3-O-glycosides was observed compared to T45 and thermal pasteurization at 85°C (T85). Moreover, cyanidins were generally more bioaccessible than delphinidins in all samples. AC after digestion was higher in SCCD samples compared to thermally treated measured using ABTS+• and DPPH• assays, whereas in dialysate similar trends were observed only for AC measured using the ABTS+• assay. This phenomenon was justified by the formation of individual metabolites detected by UPLC-PDA-MS / MS in the model experiment with delphinidin-3-O-rutinoside. The protocatechuic acid which is well known as a strong antioxidant was detected in the model experiment after digestion. Further research is needed to better understand the metabolic pathway of anthocyanins and the possible uses of SCCD to improve the health properties of fruit products.

Noise analysis in a model experiment for measuring ice loads using ice free water run

Модельный эксперимент в ледовом бассейне позволяет выяснить ледовые качества проектируемого ледостойкого морского сооружения, в том числе – получить представление о возможных ледовых нагрузках путем измерений глобальных нагрузок многокомпонентным динамометром. Чувствительность применяемого оборудования приводит к появлению шумовых помех в измеренном сигнале, вызванных действиями людей, обслуживающих эксперимент, работой машин и механизмов, гидродинамическими эффектами, а также явлениями в электросети. Отделение шумовых помех от полезного сигнала на этапе обработки данных является важной задачей, успешное решение которой позволит повысить достоверность результатов испытаний в ледовом бассейне. В настоящей работе изложен подход к очистке от шума результатов измерений многокомпонентного динамометра, применяемого в ледовом бассейне Крыловского государственного научного центра (Санкт-Петербург), с использованием амплитудно-частотного анализа участков пробега модели по чистой воде в пределах технологического окна во льду. Предложенный метод показал свою эффективность, в особенности – для экспериментов с моделью больших размеров. A model experiment in an ice tank allows to examine ice qualities of a designed ice-resistant marine structure, namely possible ice loads by measuring global loads with a multicomponent dynamometer. The sensitivity of the equipment leads to the noise interference in the measured signal caused by people's actions carrying out the experiment, by the operation of machines and mechanisms, hydrodynamic effects, as well as the phenomenae in the electrical power grid. It is important to separate noise interference from the relevant signal at the data processing stage, which will increase the reliability of ice tank experiments. This paper describes a method for denoising measurement results of a multicomponent dynamometer used in the ice tank of the Krylov State Scientific Center (St. Petersburg); the approach implies an amplitude-frequency analysis of model run areas in ice-free water within the technological window in the ice. The proposed method has demonstrated its effectiveness, especially for experiments with large models.

An Investigation on the Migration and Settlement Law of Temporary Plugging Particles in Horizontal Wellbore

Migration and settlement of temporary plugging particles of different sizes affect the effect of temporary plugging, which in turn affect the effect of reservoir reconstruction. However, the migration and settlement laws of temporary plugging particles in horizontal wellbore are still unclear. In order to study the migration and settlement laws of temporary plugging particles in horizontal wellbore, a set of multicluster perforation physical model experiment device for horizontal wells was built. Based on this experimental device, the effects of mass ratio, pumping rate, and adding sequence on the migration and settlement laws of temporary plugging particles were studied, respectively. The experimental results show that the 3 mm temporary plugging particles move forward in a leaping manner at the bottom of the horizontal wellbore and the 1 mm particles are distributed in layers in the horizontal wellbore, and the particles are less in the upper part of the wellbore and more in the bottom of the wellbore. The migration trajectory of the two mixed particles is similar to the single. Under different mass ratio, the settlement mass of particles in the perforation clusters at the outlet end is greater than that in the entrance end. When the 3 mm particles account for a relatively large amount ( m 3 mm : m 1 mm = 5 : 1 ), the settlement mass of the particles in the two perforation clusters is greater than other mass ratio conditions. For the same perforation, the settlement mass becomes greater as the proportion of 3 mm increases. When only 3 mm particles are considered, with the increasing of displacement, the mass of particles in the perforation clusters at the inlet end increases, and the mass of particles in the clusters at the outlet end decreases. With the increase of displacement, the sedimentation mass of particles in high angle perforations decreases, while the sedimentation mass in other perforations increases. Adding 3 mm first and then 1 mm particles, the particle settlement mass in the perforation cluster at the outlet end is twice the mass of the particles in the perforation cluster at the inlet end. Reversing the sequence, the settlement masses of the particles in the two clusters are almost equal. The particle distribution in the perforation at different angles has obvious gradation. The smaller the angle, the greater the settlement mass of the temporary plugging particles. This research results will provide reference for temporary plugging and fracturing construction.

Dual Effects of NV-CoV-2 Biomimetic Polymer: An Antiviral regimen against COVID-19

Remdesivir (RDV) is the only antiviral drug so far approved for COVID-19 therapy by the FDA. However its efficacy is limited in vivo due to its low stability in presence of plasma. This paper compared the stability of RDV encapsulated with our platform technology based polymer NV-387 (NV-CoV-2), in presence of plasma in vitro and in vivo . Furthermore, a non-clinical pharmacology studies of NV-CoV-2 (Polymer) and NV-CoV-2-R (Polymer encapsulated Remdesivir ) in both NL-63 infected and uninfected rats were done. In an in vitro cell culture model experiment, antiviral activity of NV-CoV-2 and NV-CoV-2-R are also compared with RDV.

Temperature-induced reorganisation of Schistocephalus solidus (Cestoda) proteome during the transition to the warm-blooded host

ABSTRACT The protein composition of the cestode Schistocephalus solidus was measured in an experiment simulating the trophic transmission of the parasite from a cold-blooded to a warm-blooded host. The first hour of host colonisation was studied in a model experiment, in which sticklebacks Gasterosteus aculeatus infected with S. solidus were heated at 40°C for 1 h. As a result, a decrease in the content of one tegument protein was detected in the plerocercoids of S. solidus. Sexual maturation of the parasites was initiated in an experiment where S. solidus larvae were taken from fish and cultured in vitro at 40°C for 48 h. Temperature-independent changes in the parasite proteome were investigated by incubating plerocercoids at 22°C for 48 h in culture medium. Analysis of the proteome allowed us to distinguish the temperature-induced genes of S. solidus, as well as to specify the molecular markers of the plerocercoid and adult worms. The main conclusion of the study is that the key enzymes of long-term metabolic changes (glycogen consumption, protein production, etc.) in parasites during colonisation of a warm-blooded host are induced by temperature.