scholarly journals Highly Stretchable Bacterial Cellulose Produced by Komagataeibacter hansenii SI1

Polymers ◽  
2021 ◽  
Vol 13 (24) ◽  
pp. 4455
Author(s):  
Izabela Cielecka ◽  
Małgorzata Ryngajłło ◽  
Waldemar Maniukiewicz ◽  
Stanisław Bielecki
Keyword(s):  
Vitamin C ◽  
Patent Application ◽  
Nitrogen Sources ◽  
Mechanical Tests ◽  
Bacterial Nanocellulose ◽  
Initial Ph ◽  
Method Of Production ◽  
Komagataeibacter Hansenii ◽  
Static Conditions ◽  
The Impact

A new strain of bacteria producing cellulose was isolated from Kombucha and identified as Komagataeibacter hansenii, named SI1. In static conditions, the strain synthesises bacterial nanocellulose with an improved ability to stretch. In this study, utilisation of various carbon and nitrogen sources and the impact of initial pH was assessed in terms of bacterial nanocellulose yield and properties. K. hansenii SI1 produces cellulose efficiently in glycerol medium at pH 5.0–6.0 with a yield of 3.20–3.60 g/L. Glucose medium led to the synthesis of membrane characterised by a strain of 77%, which is a higher value than in the case of another Komagataeibacter species. Supplementation of medium with vitamin C results in an enhanced porosity and improves the ability of bacterial nanocellulose to stretch (up to 123%). The properties of modified membranes were studied by scanning electron microscopy, Fourier transform infrared spectroscopy, X-ray diffraction and mechanical tests. The results show that bacterial nanocellulose produced in SH medium and vitamin C-supplemented medium has unique properties (porosity, tensile strength and strain) without changing the chemical composition of cellulose. The method of production BNC with altered properties was the issue of Polish patent application no. P.431265.

scholarly journals Conventional and Organic Honeys as a Source of Water- and Ethanol Soluble Molecules with Nutritional and Antioxidant Characteristics

Molecules ◽  
2021 ◽  
Vol 26 (12) ◽  
pp. 3746
Author(s):  
Magdalena Polak-Śliwińska ◽  
Małgorzata Tańska
Keyword(s):  
Antioxidant Activity ◽  
Immune System ◽  
Vitamin C ◽  
Geographical Area ◽  
Production Method ◽  
Climatic Conditions ◽  
Organic Production ◽  
Organoleptic Characteristics ◽  
Nutritional Characteristics ◽  
The Impact

The benefits of natural honeybee products (e.g., honey, royal jelly, beeswax, propolis, beevenom and pollen) to the immune system are remarkable, and many of them are involved in the induction of antibody production, maturation of immune cells and stimulation of the immune system. The type of plants in the geographical area, climatic conditions and production method have a significantly influence on the nutritional quality of honey. However, this variability can influence consumer liking by the sensory attributes of the product. The aim of this work was to compare the most popular honeys from Poland in terms of nutritional value, organoleptic properties and antioxidant activity. In the study, five varieties of honey (honeydew, forest, buckwheat, linden and dandelion) from conventional and organic production methods were tested. The nutritional characteristics of honey samples included acidity, content of water, sugars, vitamin C, HMF and phenolics (total and flavonoids), while honey color, taste, aroma and consistency were investigated in the organoleptic characteristics. The antioxidant activity was determined in water- and ethanol-soluble honey extracts using DPPH and ORAC tests. The results showed that organoleptic and nutritional characteristics of popular Polish honeys differ significantly in relation to plant source and production method. The significant effect of honey variety on the content of HMF, saccharose and phenolics, as well as acidity and antioxidant capacity were noted. The impact of variety and variety × production method interaction was significant in the case of the content of vitamin C, glucose and fructose. A visible difference of buckwheat and forest honeys from other samples was observed. The highest content of total phenolics with antioxidant activity based on the SET mechanism was found in buckwheat honeys, while forest honeys were richer in flavonoids.

Impaired Platelet Function in Sept8-Deficient Mice In Vitro

2020 ◽  
Author(s):  
Kerstin Jurk ◽  
Katharina Neubauer ◽  
Victoria Petermann ◽  
Elena Kumm ◽  
Barbara Zieger
Keyword(s):  
Platelet Function ◽  
Thrombin Generation ◽  
Human Platelets ◽  
Platelet Surface ◽  
Integrin Αiibβ3 ◽  
Glycoprotein Vi ◽  
Fibrinogen Receptor ◽  
Static Conditions ◽  
The Impact

AbstractSeptins (Septs) are a widely expressed protein family of 13 mammalian members, recognized as a unique component of the cytoskeleton. In human platelets, we previously described that SEPT4 and SEPT8 are localized surrounding α-granules and move to the platelet surface after activation, indicating a possible role in platelet physiology. In this study, we investigated the impact of Sept8 on platelet function in vitro using Sept8-deficient mouse platelets. Deletion of Sept8 in mouse platelets caused a pronounced defect in activation of the fibrinogen receptor integrin αIIbβ3, α-granule exocytosis, and aggregation, especially in response to the glycoprotein VI agonist convulxin. In contrast, δ-granule and lysosome exocytosis of Sept8-deficient platelets was comparable to wild-type platelets. Sept8-deficient platelet binding to immobilized fibrinogen under static conditions was diminished and spreading delayed. The procoagulant activity of Sept8-deficient platelets was reduced in response to convulxin as determined by lactadherin binding. Also thrombin generation was decreased relative to controls. Thus, Sept8 is required for efficient integrin αIIbβ3 activation, α-granule release, platelet aggregation, and contributes to platelet-dependent thrombin generation. These results revealed Sept8 as a modulator of distinct platelet functions involved in primary and secondary hemostatic processes.

Dynamic Ultimate Strength Characteristics of Stiffened Plates Subjected to the In-Plane Impact Load and Lateral Pressure

2021 ◽  
Author(s):  
Qiang Zhong ◽  
De-yu Wang
Keyword(s):  
Finite Element ◽  
Ultimate Strength ◽  
Lateral Pressure ◽  
Impact Load ◽  
Strength Characteristics ◽  
Stiffened Plates ◽  
Strength Theory ◽  
Explicit Finite Element ◽  
Static Conditions ◽  
The Impact

Abstract Dynamic capacity is totally different from quasi-static capacity of ship structural components, although most ultimate strength analyses at present by researchers are performed under quasi-static conditions. To investigate the dynamic ultimate strength characteristics, the dynamic ultimate strength analyses of stiffened plates subjected to impact load were studied based on a 3-D nonlinear explicit finite element method (FEM) in this paper. The impact load in the present work is characterized as a half-sine function. A series of nonlinear finite element analyses are carried out using Budiansky-Roth (B-R) criterion. The influence of impact durations, model ranges, boundary conditions, initial imperfections and impact loads on the dynamic ultimate strength of stiffened plates are discussed. In addition, the ultimate strength of stiffened plates under the in-plane impact combined with lateral pressure was also calculated, which shows lateral pressure has a negligible effect on the dynamic ultimate strength of stiffened plates subjected to the impact load with short durations. Other important conclusions can be obtained from this paper, which are useful insights for the development of ultimate strength theory of ship structures and lay a good foundation for the study of dynamic ultimate strength in the future.

scholarly journals Ultra-High Temperature Effect on Bioactive Compounds and Sensory Attributes of Orange Juice Compared with Traditional Processing

2017 ◽  
Vol 71 (6) ◽  
pp. 486-491
Author(s):  
Gaļina Zvaigzne ◽  
Daina Kārkliņa ◽  
Joerg-Thomas Moersel ◽  
Sasha Kuehn ◽  
Inta Krasnova ◽  
...  
Keyword(s):  
High Temperature ◽  
Vitamin C ◽  
Bioactive Compounds ◽  
Orange Juice ◽  
Sensory Attributes ◽  
Heat Treated ◽  
C 30 ◽  
Traditional Processing ◽  
The Impact ◽  
Ultra High Temperature

Abstract Orange juices are an important source of bioactive compounds. Because of its unique combination of sensory attributes and nutritional value, orange juice is the world’s most popular fruit juice. Orange (Citrus sinensis) juice of Greek Navel variety was used in this study. The impact of Conventional Thermal Pasteurisation (94 °C/30') (CTP) and alternative Ultra-High Temperature (UHT) (130 °C/2') processing on bioactive compounds and antioxidant capacity changes of fresh Navel orange juice was investigated. Sensory attributes of processed juices were evaluated. Results showed that using technologies CTP and UHT orange juice Navel significantly changed vitamin C concentration in comparison with fresh orange juice. The highest concentration of antioxidants (vitamin C, total phenols, hesperidin and carotenoids) was observed in orange juice Navel produced by UHT technology. Sensory results indicated that characteristics of the orange juice obtained using UHT technology were more liked than the CTP heat treated juice. UHT technology emerges as an advantageous alternative process to preserve bioactive compounds in orange juice.

scholarly journals A Theoretical and Experimental Study of Electrochemical pH Control at Gold Interdigitated Microband Arrays

2021 ◽  
Author(s):  
Bernardo Patella ◽  
Robert Daly ◽  
Ian Seymour ◽  
Pierre Lovera ◽  
James Rohan ◽  
...  
Keyword(s):  
Electrode Array ◽  
Ph Control ◽  
Reduction Peak ◽  
Solution Ph ◽  
Ph Indicator ◽  
Ph Change ◽  
Initial Ph ◽  
The Impact ◽  
Strong Acids

In electroanalysis, solution pH is a critical parameter that often needs to be adjusted and controlled for the detection of particular analytes. This is most commonly performed by the addition of chemicals, such as strong acids or bases. Electrochemical in-situ pH control offers the possibility for the local adjustment of pH at the point of detection, without additional reagents. FEA simulations have been performed to guide experimental design for both electroanalysis and in-situ control of solution pH. No previous model exists that describes the generation of protons at an interdigitated electrode array in buffered solution with one comb acting as a protonator, and the other as the sensor. In this work, FEA models are developed to provide insight into the optimum conditions necessary for electrochemical pH control. The magnitude of applied galvanostatic current has a direct relation to the flux of protons generated and subsequent change in pH. Increasing the separation between the electrodes increases the time taken for protons to diffuse across the gap. The final pH achieved at both, protonators and sensor electrodes, after 1 second, was shown to be largely uninfluenced by the initial pH of the solution. The impact of buffer concentration was modelled and investigated. In practice, the pH at the electrode surface was probed by means of cyclic voltammetry, i.e., by cycling a gold electrode in solution and identifying the potential of the gold oxide reduction peak. A pH indicator, methyl red, was used to visualise the solution pH change at the electrodes, comparing well with the model’s prediction

scholarly journals Impact of the Emerging COVID-19 Pandemic on the Consumption of Multivitamins (C, D and Zinc) by the Saudi Arabian Population

2021 ◽  
pp. 11-20
Author(s):  
Duaa Mohamed Bakhshwin ◽  
Abdulaziz Bakhshwin
Keyword(s):  
Vitamin D ◽  
Vitamin C ◽  
World Health ◽  
Saudi Population ◽  
Viral Spread ◽  
Significant Difference ◽  
Before And After ◽  
Zinc Supplements ◽  
Vitamin D Supplements ◽  
The Impact

Background: On March 11, 2020, the World Health Organization (WHO) announced the Coronavirus outbreak officially as a pandemic. This pandemic has led to new measurements to prevent viral spread. The measures included decreasing the person’s mobility outside homes with subsequent changes in the lifestyles, particularly in physical activity and eating habits. It has been noticed that consumption of some vitamins may help in preventing or reducing the symptoms of viral infection. Those vitamins include vitamin C, D and zinc. There is a common observation that the general public believes that the use of vitamins, especially vitamins C, D and zinc, reduces the chance of acquiring COVID-19. Objectives: The aim of this study was to determine the impact of COVID-19 pandemic on taking vitamins supplements by the Saudi general population in order to explore their believes regarding the protective value of these vitamins against COVID-19 infection. Subjects and Methods: This cross-sectional study was conducted using a self-administrated questionnaire that was designed, uploaded to the Google form and distributed online to the general Saudi population through the social media (Whatsapp, Twitter) as well as through email between August and December 2020. Statistical Packaged of Social Sciences program (SPSS) for Windows (version 17.0., Chicago: SPSS Inc) was used to analyze the data. A significant difference was considered when the p value is < 0.05. Student t-test and Chi-square (χ2) test were used to compare the studied variables as appropriate. Results: A total of 1043 participants were included in this study (64.9% females, 35.1% males). The mean age for them was 35.3±14.78 years. Only 9.3% (97 participants) were diagnosed to have COVID-19. About 28% of the participants were in contact with COVID-19 cases. Among participants diagnosed to have COVID-19 infection, (13% versus 29%) were taking vitamin C and (2% versus 15%) were taking zinc supplements daily during the 6 months before and after the pandemic, respectively, while (20% versus 25%) were taking vitamin D supplements weekly during the 6 months before and after the pandemic, respectively. Among participants who were in contact with COVID-19 cases, (8% versus 20%) and (3% versus 11%) were taking vitamin C and zinc supplements daily during the 6 months before and after the pandemic, respectively, while (14% versus 16%) were taking vitamin D supplements weekly during the 6 months before and after the pandemic Conclusion: The interest of taking multivitamin by Saudi population, such as vitamins C and D, zinc increased during and after the pandemic compared to that before it. There is no scientific evidence based on previous studies confirmed the role of dietary supplementation and multivitamins in preventing COVID-19 infection, therefore, effective education on the rationale use of vitamins during COVID-19 pandemic should be emphasized at local and/or national levels.

scholarly journals Mechanical Performance Under Various Conditions of 3D Printed Polylactide Composites With Natural Fibers

2021 ◽  
Author(s):  
Karolina E. Mazur ◽  
Aleksandra Borucka ◽  
Paulina Kaczor ◽  
Szymon Gądek ◽  
Stanislaw Kuciel
Keyword(s):  
Elevated Temperatures ◽  
Mechanical Performance ◽  
Natural Fibers ◽  
Crystallization Rate ◽  
Mechanical Tests ◽  
Hydrothermal Degradation ◽  
3D Printed ◽  
The Impact ◽  
Different Levels ◽  
Additive Methods

Abstract In the study, polylactide-based (PLA) composites modified with natural particles (wood, bamboo, and cork) and with different levels of infilling (100%, 80%, and 60%) obtained by additive methods were tested. The effect of type fiber, infill level and crystallization rate on the mechanical properties were investigated by using tensile, flexural, and impact tests. The materials were subjected to mechanical tests carried out at 23 and 80 °C. Furthermore, hydrothermal degradation was performed, and its effect on the properties was analyzed. The addition of natural fillers and different level of infilling result in a similar level of reduction in the properties. Composites made of PLA are more sensitive to high temperature than to water. The decrease in Young's modulus of PLA at 80 °C was 90%, while after 28 days of hydrodegradation ~ 9%. The addition of fibers reduced this decrease at elevated temperatures. Moreover, the impact strength has been improved by 50% for composites with cork particles and for other lignocellulosic composites remained at the same level as for resin.

scholarly journals The Use of the Collocation Algorithm for Estimating the Deformations of Soil-Shell Objects Made of Corrugated Sheets

2020 ◽  
Vol 0 (0) ◽  
Author(s):  
Czesław Machelski
Keyword(s):  
Strain Gauges ◽  
Boundary Constraints ◽  
Axial Forces ◽  
Collocation Points ◽  
Geodetic Measurements ◽  
Significant Divergence ◽  
Internal Forces ◽  
Support Conditions ◽  
Static Conditions ◽  
The Impact

AbstractThe algorithm presented in this paper is intended for the analysis of deformations of shells in the construction phase of soil-shell objects when strain gauges and geodetic measurements are used. During the construction of such an object, large displacement values occur and the impact of axial forces on the displacement of a corrugated metal sheet is small. Internal forces (strain gauges), as well as the displacements of a selected circumferential band of the shell are determined directly from such observations.The paper presents two examples of the analysis of large span shell structures of constructed objects, as well as the assessment of the effectiveness of the finite difference method (FDM) in beam schemes. Good deformation mapping was indicated using the collocation algorithm and the differential approach to the solution when there is a dense mesh and regular distribution of measuring points. In the analysed examples, a significant divergence between the support conditions adopted in the FEM calculation models and the actual static conditions in the objects was indicated. The collocation algorithm is especially designed for such situations. Collocation points in such a solution are used to consider a beam – separated from a structure and without boundary constraints, but with specific changes in curvature – as a reference system, which is determined from the geodetic measurements of two collocation points.

scholarly journals Effect of adding TiO2 nanoparticles on the SEM morphology and mechanical properties of conventional heat-cured acrylic resin

2019 ◽  
Vol 13 (3) ◽  
pp. 234-240
Author(s):  
Elnaz Moslehifard ◽  
Mahmood Robati Anaraki ◽  
Saeed Shirkavand
Keyword(s):  
Impact Strength ◽  
Tio2 Nanoparticles ◽  
Cross Sections ◽  
Average Particle Size ◽  
Acrylic Resin ◽  
Mechanical Tests ◽  
Average Particle ◽  
Sem Images ◽  
Tio2 Nps ◽  
The Impact

Background. The current study evaluated the compressive, flexural and impact strengths of heat-cured acrylic resins reinforced by TiO2 nanoparticles (NPs). Methods. TiO2 NPs were provided and characterized using scanning electron microscopy (SEM) to determine their morphology and crystalline structure. For three mechanical tests, 12 acrylic resin groups (n=9), totaling 108 specimens, were prepared using a special mold for each test, with TiO2 nanoparticle contents of 0, 0.5, 1 or 2 wt% in different groups. After curing, the compressive, flexural and impact strengths of the specimens were examined according to ISO 1567. Results. In the SEM and XRD study of TiO2 NPs, anatase was identified as the major crystalline phase followed by rutile (average particle size: 20.4 nm). SEM images showed that the nanocomposite with 1 wt% NPs had a more homogenized blend. 1 wt% TiO2 nanocomposite exhibited a higher, but non-significant, impact strength compared to the controls. ANOVA showed significant differences in the impact and flexural strengths between nanocomposites with various contents of TiO2 NPs. Conclusion. The nanocomposite with 1 wt% TiO2 NPs exhibited fewer micro-pores and micro-cracks in the SEM cross-sections. A non-significant increase was also observed in the impact strength with TiO2 NPs at 1 wt%. Further increase in TiO2 NPs decreased both the impact and flexural strengths. The compressive strength of the heat-cured acrylic resin was not affected by the incorporation of NPs.

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