scholarly journals Thermokinetics and rheology of agarose gel applied to bioprinting technology

2020 ◽  
Vol 24 (1 Part A) ◽  
pp. 347-353
Author(s):  
Boris Pokusaev ◽  
Andrey Vyazmin ◽  
Nikolay Zakharov ◽  
Sergey Karlov ◽  
Dmitry Nekrasov ◽  
...  
Keyword(s):  
Rheological Properties ◽  
Point Of View ◽  
Gel Formation ◽  
Operating Modes ◽  
Preliminary Preparation ◽  
Immobilized Microorganisms ◽  
The Stability ◽  
And Storage ◽  
Kinetics Of ◽  
Selection Of

The paper presents new results on the study of thermokinetics of gel system based on agarose in the process of transition from solution to gel and opposite. This issue is extremely relevant, since the stability and predictability of thermophysical and rheological properties in such transformations, especially in the presence of components of the nutrient medium and immobilized microorganisms, come to the fore in terms of design and selection of modes of operation of the printing device promising 3-D bioprinters, as well as the system of preparation and storage of the presence of the hysteresis effect, both from the point of view of the kinetics of gel formation and from the point of view of the dependence of rheological properties on temperature, at different concentrations of modifying components, is shown. The obtained results allow to draw a conclusion about the possibility of using the scheme with preliminary preparation of the initial biogel for the implementation of bioprinting technology based on agarose, and to recommend the obtained values for modeling the operating modes of devices of this type.

Development of a rapid screening protocol for selection of strains resistant to spray drying and storage in dry powder

2010 ◽  
Vol 1 (2) ◽  
pp. 165-174 ◽  
Author(s):  
S. Reimann ◽  
F. Grattepanche ◽  
C. Baggenstos ◽  
E. Rezzonico ◽  
B. Berger ◽  
...  
Keyword(s):  
Spray Drying ◽  
Bifidobacterium Longum ◽  
Survival Rates ◽  
Screening Method ◽  
Rapid Screening ◽  
Fast Screening ◽  
Screening Protocol ◽  
The Stability ◽  
And Storage ◽  
Selection Of

An efficient screening method for selection of Bifidobacterium longum strains resistant to spray drying and storage was developed based on randomly amplified polymorphic DNA (RAPD) for identification of the best survivors in mixed strains bacterial preparations. Three different primers were used to generate RAPD profiles of 22 B. longum strains. All strains were distinguished according to their RAPD profiles except for the strain NCC2705 and its H2O2 resistant derivative variant. The 22 strains were grouped in 3 batches of 7, 7 and 8 strains and subjected to spray drying and storage at 30 and 37 °C under anaerobic conditions. Batch survival rates after spray drying reached 17.1±4.4%. Strains showing the highest prevalence and/or resistance to storage at 37 °C were selected from individual batches for subsequent spray drying and storage testing. After 67 days of storage, NCC572 was identified as the dominant strain in powder. The stability of strain NCC572 was confirmed by performing single spray drying and storage tests. Out of 22 B. longum strains, a robust strain was identified by combining RAPD with a simultaneous screening test for survival under spray drying and storage. The method allowed a fast screening of B. longum strains in mixture for resistance to spray drying and storage compared to traditional screening procedures carried out with individual strains, in the same conditions. This approach could be applied to other stress conditions.

scholarly journals THE EFFECT OF PLANT PROTEINS ON THE FORMATION OF STRUCTURAL AND RHEOLOGICAL PROPERTIES OF NOUGAT

2020 ◽  
Vol 14 (4) ◽  
Author(s):  
L. Gordiienko ◽  
V. Tolstykh ◽  
K Avetisian
Keyword(s):  
Rheological Properties ◽  
Nutritional Value ◽  
Unsaturated Fatty Acids ◽  
Foam Stability ◽  
Soya Protein ◽  
Plant Proteins ◽  
Plastic Strength ◽  
Calcium Magnesium ◽  
The Stability ◽  
Kinetics Of

This paper considers the problem of increasing  the nutritional value of whipped confectionery such as nougat by using hemp- based and soya-based protein-containing ingredients. The  main  tendencies of obtaining new types of food based on plant proteins with complete amino acid composition are described. The paper presents information on cultivating and using hemp and soya both in Ukraine and in the world, and suggests how products of their processing can be applied to improve the quality and increase the biological value of confectionery. It has been investigated what effect protein-containing ingredients obtained from hemp and soya have on the structural properties of foam in the technology of whipped confectionery such as nougat. It has been  established  that increasing the amount of plant protein additives leads to a decrease in the foaming ability, but the stability of protein foams increases. Adding 10% of protein-containing hemp additives increases the foam stability by 6%, while protein-containing soya additives increase it by 5%. The paper presents the results of studying the structural and rheological properties of nougat mass with protein-containing plant additives in the amount 2.5–10% of the weight of sugar. It has been determined that adding protein-containing hemp and soya ingredients increases the viscosity and plastic strength of the products and stabilises their structure. The effect of different amounts of nuts on the kinetics of nougat crystallisation has been studied. It is recommended to add 5% of hemp and 7.5% of soya protein-containing additives instead of sugar during the whipping of nougat mass, because it reduces the whipping time and has a positive effect on structure formation. The recommended  amount of roasted pistachio kernels in the samples suggested is 25–35% of the total weight of nougat, with the resting time 30–60 minutes and the moulding temperature 50–55°C. The nutritional value of the new products with protein-containing hemp and soya  ingredients and nuts has been calculated. It has been noted that nougat has been enriched with protein, unsaturated  fatty acids, and minerals (potassium, calcium, magnesium, phosphorus).

scholarly journals Stability analysis of the Kosciuszko Mound using terrestrial laser scanner and numerical modelling

2018 ◽  
Vol 66 ◽  
pp. 01018
Author(s):  
Elżbieta Pilecka ◽  
Karolina Tomaszkiewicz
Keyword(s):  
Stability Analysis ◽  
Laser Scanner ◽  
Technical Condition ◽  
Point Of View ◽  
Terrestrial Laser Scanner ◽  
The Finite Element Method ◽  
Anthropogenic Soils ◽  
Differential Model ◽  
The Stability ◽  
Selection Of

Landslides which form in anthropogenic soils are complicated from a geological engineering and geotechnical point of view. Each case requires a detailed investigation and the selection of effective reinforcements is a difficult project issue. The study presents the problem of the stability analysis of landslides occurring in the anthropogenic soils of the Kosciuszko Mound in Cracow. The previously performed protections are discussed to highlight their ineffectiveness and the current technical condition of the mound is also presented. By overlapping the results of displacement measurements made with a terrestrial laser scanner, a differential model of the terrain was created which made it possible to determine the size and direction of the deformation of the slopes of the mound and the tendencies for the development of landslide movements in this area. A cross-section, selected on the basis of the model, was numerically analysed using the finite element method (FEM) in the Midas GTS NX program. As a result of the analysis, the values of the displacements and strains occurring in the Mound were calculated. On the basis of the value of the safety factor obtained, it was also possible to assess the risk of landslide movements.

scholarly journals The Effect of the Antioxidant Activity of Plant Extracts on the Properties of Gold Nanoparticles

Nanomaterials ◽  
2019 ◽  
Vol 9 (12) ◽  
pp. 1655 ◽  
Author(s):  
Natalia Yu. Stozhko ◽  
Maria A. Bukharinova ◽  
Ekaterina I. Khamzina ◽  
Aleksey V. Tarasov ◽  
Marina B. Vidrevich ◽  
...  
Keyword(s):  
Antioxidant Activity ◽  
Gold Nanoparticles ◽  
Sodium Citrate ◽  
Formation Rate ◽  
Leaf Extracts ◽  
Absolute Value ◽  
Transmission Electron ◽  
The Stability ◽  
Kinetics Of ◽  
Selection Of

Synthesis of gold nanoparticles (phyto-AuNPs) with the use of leaf extracts (phytosynthesis) is based on the concept of Green Chemistry. The present study is conducted to discuss how antioxidant activity (AOA) of extracts from plant leaves impacts on the kinetics of phytosynthesis, the size of the formed nanoparticles, and the stability of their nanosuspensions. Results show that the formation rate of phyto-AuNPs suspensions accelerate due to the increase in the AOA of the extracts. Accompanying the use of transmission electron microscopy (TEM), UV-Vis-spectrophotometry and dynamic light scattering (DLS), it also has been found that higher AOA of the extracts leads to a decrease in the size of phyto-AuNPs, an increase in the fraction of small (d ≤ 5 nm), and a decrease in the fraction of large (d ≥ 31–50 nm) phyto-AuNPs, as well as an increase in the zeta potential in absolute value. Phyto-AuNPs suspensions synthesized with the use of extracts are more resistant to destabilizing electrolytes and ultrasound, as compared to suspensions synthesized using sodium citrate. Thus, the AOA of the extract is an important parameter for controlling phytosynthesis and predicting the properties of phyto-AuNPs. The proposed approach can be applied to the targeted selection of plant extract that will be used for synthesizing nanoparticles with desired properties.

scholarly journals Kinetics of Lycopene Degradation in Sunflower and Grape Seed Oils

2018 ◽  
Vol 34 (5) ◽  
pp. 2229-2235 ◽  
Author(s):  
Antonio Zuorro ◽  
Roberto Lavecchia ◽  
Erenio González ◽  
Viatcheslav Kafarov
Keyword(s):  
Seed Oil ◽  
Storage Temperature ◽  
Degradation Kinetics ◽  
Grape Seed ◽  
Antioxidant Compounds ◽  
First Order Kinetics ◽  
Grape Seed Oil ◽  
The Stability ◽  
And Storage ◽  
Kinetics Of

The stability of lycopene in two vegetable oils, sunflower seed oil (SSO) and grape seed oil (GSO), was investigated by analysing the carotenoid degradation kinetics in the temperature range of 10–40°C. A tomato oleoresin containing 6% (w/w) of lycopene was used to prepare lycopene-enriched oil samples. Analysis of kinetic data showed that lycopene degradation follows first-order kinetics, with an apparent activation energy of 70.7 kJ mol–1 in SSO and 69 kJ mol–1 in GSO. The estimated half-life of lycopene was found to depend on oil type and storage temperature. At 20°C, it varied between 59 and 122 days, while at 4°C it was comprised between 302 and 650 days. At all temperatures, lycopene was more stable in SSO than in GSO, which is likely due to the higher content of antioxidant compounds in SSO.

scholarly journals A Fuzzy Method for Joint Resource Allocation and Stable Pairing in D2D Communications with Applications in COVID-19 Patient Information Management

2021 ◽  
Author(s):  
Alireza Pourmoslemi ◽  
Siavash Rajabi ◽  
Mehdi Salimi ◽  
Massimiliano Ferrara
Keyword(s):  
Resource Allocation ◽  
Point Of View ◽  
D2d Communications ◽  
Fuzzy Method ◽  
Random Pairing ◽  
Joint Resource Allocation ◽  
Rate Method ◽  
Sum Rate ◽  
The Stability ◽  
Selection Of

Abstract In this paper, a device-to-device (D2D) communication multiple-metric scenario for resource allocation and pairing is proposed. To improve the stability of the D2D connection, a fuzzy method based on the data-rate and battery levels of potential D2D pairs is studied so that the set of D2D transmitters is considered as a fuzzy set. A single-cell scenario with a cellular user and some co-channel D2D nodes consisting of D2D receivers and transmitters is considered. A stable fuzzy pairing criterion is proposed for the selection of the best D2D transmitter. The proposed method is compared to three other pairing methods: maximum sum-rate, constant, and random pairing methods. The simulation results show that the proposed pairing method outperforms the other three methods in terms of stability and fairness criteria and follows the maximum sum-rate method from the sum-rate criteria point of view.

scholarly journals Solubility, Rheology, and Coagulation Kinetics of Poly-(O-Aminophenylene)Naphthoylenimide Solutions

Polymers ◽  
2020 ◽  
Vol 12 (11) ◽  
pp. 2454
Author(s):  
Ivan. Y. Skvortsov ◽  
Valery G. Kulichikhin ◽  
Igor I. Ponomarev ◽  
Lydia A. Varfolomeeva ◽  
Mikhail S. Kuzin ◽  
...  
Keyword(s):  
Rheological Properties ◽  
Time Window ◽  
Polymer Concentration ◽  
Effect Of Temperature ◽  
Coagulation Bath ◽  
Continuous Polymerization ◽  
Coagulation Kinetics ◽  
The Stability ◽  
First Time ◽  
Kinetics Of

The effect of temperature and storage time at a constant temperature on the stability of poly-(o-aminophenylene)naphthoylenimide solutions in N-methylpyrrolidone has been analyzed using rotational rheometry. A temperature–time window beyond which an irreversible change in the viscoelastic properties of solutions due to cumulative reactions of continuous polymerization and possible intramolecular cyclization has been detected. The influence of polymer concentration and its molecular weight on the rheological properties of solutions determining the choice of methods for their processing into fibers and films has been investigated. The effect of non-solvents (water and ethanol) additives on the rheological properties of solutions and the kinetics of their coagulation has been studied. Dosed addition of non-solvent into the solution promotes a significant increase in the viscoelasticity up to gelation and phase separation. Non-solvent presence in the polymer solutions reduces the activity of the solvent, accelerates the movement of the diffusion front at coagulation, and minimizes the number of macro defects. The combination of parameters under investigation renders it possible for the first time to develop new principles modifying dopes for wet spinning into aqueous or ethanol coagulation bath and finally to obtain a heat- and fire-resistant polynaphthoylenebenzimidazole fibers.

scholarly journals Implementation of Mass Cytometry for Immunoprofiling of Patients with Solid Tumors

2019 ◽  
Vol 2019 ◽  
pp. 1-10
Author(s):  
Ingrid Poláková ◽  
Ondřej Pelák ◽  
Daniel Thürner ◽  
Barbora Pokrývková ◽  
Ruth Tachezy ◽  
...  
Keyword(s):  
Sample Preparation ◽  
Immune Responses ◽  
Immune Cells ◽  
Tumor Tissue ◽  
Important Criterion ◽  
Mass Cytometry ◽  
The Stability ◽  
And Storage ◽  
Selection Of ◽  
Conventional Staging

Monitoring immune responses to solid cancers may be a better prognostic tool than conventional staging criteria, and it can also serve as an important criterion for the selection of individualized therapy. Multiparametric phenotyping by mass cytometry extended possibilities for immunoprofiling. However, careful optimization of each step of such method is necessary for obtaining reliable results. Also, with respect to procedure length and costs, sample preparation, staining, and storage should be optimized. Here, we designed a panel of 31 antibodies which allows for identification of several subpopulations of lymphoid and myeloid cells in a solid tumor and peripheral blood simultaneously. For sample preparation, disaggregation of tumor tissue with two different collagenases combined with DNase I was compared, and removal of dead or tumor cells by magnetic separation was evaluated. Two possible procedures of barcoding for single-tube staining of several samples were examined. While the palladium-based barcoding affected the stability of several antigens, the staining with two differently labeled CD45 antibodies was suitable for cells isolated from a patient’s blood and tumor. The storage of samples in the intercalation solution for up to two weeks did not influence results of the analysis, which allowed the measurement of samples collected within this interval on the same day. This procedure optimized on samples from patients with head and neck squamous cell carcinoma enabled identification of various immune cells including rare subpopulations.

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