Polyhydroxyalkanoates in Bacterial Cells - More Than just Storage Materials

2016 ◽  
Vol 851 ◽  
pp. 20-25 ◽  
Author(s):  
Stanislav Obruca ◽  
Leos Doskocil ◽  
Vladislav Krzyzanek ◽  
Kamila Hrubanova ◽  
Petr Sedlacek ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Carbon Sources ◽  
Chemical Properties ◽  
Dry Weight ◽  
Natural Environments ◽  
Bacterial Cells ◽  
Surface Absorption ◽  
Storage Materials ◽  
Physico Chemical ◽  
Bacterial Cytoplasm

Since polyhydroxyalkanoates (PHAs) belong among the most widespread storage materials within bacteria genus, it can be assumed that the ability of PHAs accumulation represent significant advantage in the natural environments. Of course, probably the most obvious is the possibility to utilize PHAs when external carbon sources are depleted. Nevertheless, it is likely that PHAs play much more complex role in the stress response of bacteria. Therefore, the aim of this work was to investigate possible influence of PHA accumulation in bacteria on physical properties of the cells and their cytoplasm with respect to possible stress survival. Cells of bacteria Cupriavidus necator H16 with various poly(3-hydroxybutyrate) (PHB) content (25 – 91 % of cell dry weight) were subjected to analytical centrifugation employing LUMiSizer. We observed that slope of index instability of bacterial culture increased with rise of PHB content in cells. It indicates that accumulation of PHB granules in bacterial cells affects overall physico-mechanical properties of the cells in particular sedimentation potential and density which might influence their behavior in natural environment such as sedimentation, surface absorption and subsequent biofilm formation. Furthermore, when investigated by Cryo-SEM, the PHB containing cells showed needle-type plastic deformations while these structures were absent in the cells without polymer. This suggests that native intracellular PHB granules reveal completely different mechanical and physico-chemical properties than any other component of bacterial cytoplasm and their flexibility even in deeply-frozen state is significantly higher than that of PHB isolated from bacterial cells. Based on these observations, it can be expected that, aside from their involvement in metabolism, presence of PHB granules dramatically changes physico-mechanical properties of cytoplasm and overall properties of cells which might represent important advantage when cells are exposed to stress conditions.

scholarly journals Mechanical Properties of U-Cu Intermetallic Compound Measured by Nanoindentation

Materials ◽  
2018 ◽  
Vol 11 (11) ◽  
pp. 2215 ◽  
Author(s):  
Ruiwen Li ◽  
Chuan Mo ◽  
Yichuan Liao
Keyword(s):  
Mechanical Properties ◽  
Intermetallic Compound ◽  
Chemical Properties ◽  
Element Distribution ◽  
Treatment Temperature ◽  
Diffusion Method ◽  
Vacuum Furnace ◽  
Young’S Moduli ◽  
Pressure Diffusion ◽  
Physico Chemical

The physico-chemical properties of the Uranium intermetallic compound are of technological importance for improvement of the safety and compatibility of nuclear engineering systems. Diffusion couple samples with U and Cu were assembled and U-Cu intermetallic compounds were fabricated at interface by hot pressure diffusion method at a treatment temperature of 350 °C to 650 °C and at a pressure of 168 MPa in a vacuum furnace. The microstructure and element distribution of the compound phase have been studied by means of SEM, EDS, and XRD. The result showed that a new phase was developed to a thickness of approximately 10 μm with a ration of U:Cu with 1:5. Mechanical properties such as elastic moduli and hardness of the compound have been studied by means of nanoindentation. The nanoindentation testing on sample indicated that hardness of Uranium intermetallic compound are higher than that of metal U and Cu. Uranium intermetallic compound and U have a Young’s moduli with 121 GPa, 160 GPa respectively. The elastic/plastic responses of U-Cu intermetallic compound and U under nanoindentation tests were also discussed in detail.

Strain Energy and Behaviour of Overconsolidated Soils

1967 ◽  
Vol 4 (3) ◽  
pp. 326-333 ◽  
Author(s):  
Elmer W Brooker
Keyword(s):  
Mechanical Properties ◽  
Strain Energy ◽  
Large Scale ◽  
Chemical Properties ◽  
Earth Pressure ◽  
Quantitative Evidence ◽  
Physico Chemical ◽  
Overconsolidated Clays ◽  
Overconsolidated Soils

Bjerrum recently presented a strain energy hypothesis which explains qualitatively the behaviour of overconsolidated clays and the phenomena of long-term slope failures in these soils. Quantitative evidence, gathered from a series of large-scale consolidation tests, is presented here which supports the strain energy hypothesis. The coefficient of earth pressure at rest was found to be a function of strain energy at a given value of OCR. It is also shown that the degree of disintegration of overconsolidated soils during a slaking test is related to strain energy. It is inferred from the results that mineralogy and the capacity of a soil to adsorb strain energy are related. The evidence suggests that certain physico-chemical properties may be quantitatively related to mechanical properties through the concept of strain energy.

scholarly journals Evolution of an alumina-magnesia/self-forming spinel castable. Part II: physico-chemical and mechanical properties

Cerâmica ◽  
1999 ◽  
Vol 45 (295) ◽  
pp. 146-149
Author(s):  
D. Gutiérrez-Campos ◽  
J. I. Diaz ◽  
R. M. Rodriguez
Keyword(s):  
Mechanical Properties ◽  
Bulk Density ◽  
Chemical Properties ◽  
Microstructural Characteristics ◽  
Crushing Strength ◽  
Physico Chemical ◽  
Cold Crushing Strength

This study was carried out in conjunction with the investigation, reported in Part I, on the microstructural characteristics of an alumina-spinel castable with several percentages of MgO content. Bulk density and cold crushing strength of samples were evaluated dried and at three fired states (1000, 1200, 1400 °C). Results indicate little influence of MgO additions on physico-chemical properties of the alumina-magnesia/self-forming spinel castable. Characteristics compared with those reported for conventional alumina-spinel castables did not show large difference in values. Therefore, the alumina-magnesia/self-forming spinel castable could be a possible material for substitution of the conventional alumina-spinel castable.

scholarly journals Investigations on physico-chemical properties of TSPCU nonwoven for application as prosthetic venous valve

2021 ◽  
Vol 7 (2) ◽  
pp. 613-616
Author(s):  
Julia Schubert ◽  
Daniela Arbeiter ◽  
Andreas Götz ◽  
Kerstin Lebahn ◽  
Wolfram Schmidt ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Chemical Properties ◽  
Storage Conditions ◽  
Valve Leaflet ◽  
Venous Valve ◽  
Sem Images ◽  
Venous Valves ◽  
Prosthetic Valves ◽  
Physico Chemical ◽  
3D Printed

Abstract Electrospinning is used for producing nonwovens for medical polymer-based implants, such as prosthetic valves or covered scaffolds. In this study, nonwovens for prosthetic venous valves are investigated regarding their morphology and mechanics in physiological medium. Spinning molds were developed based on previous venous valve leaflet designs, 3D printed in different sizes and covered with electrospun nonwovens. Samples were stored in a physiological 0.9% saline at 37°C to investigate the influence of fiber rearrangement and swelling in medium for several weeks. Two different nonwovens of thermoplastic silicone-based polycarbonaturethane (TSPCU) were compared. Tensile test results show that storage in medium has a relevant influence on the mechanical properties. SEM images of TSPCU show substantially increased fiber diameters after 8 days stored in medium. After detaching the valve leaflet nonwovens from the molds, shrinkage of the material of approximately 12% was detected. A suitable valve size could be identified for joining with the stent structure into an interventional prosthetic venous valve. The results demonstrate the influence of storage conditions on the morphological and mechanical properties of electrospun TSPCU nonwovens. For development and dimensioning of venous valve leaflets, this change in mechanical behavior and possible shrinkage of the material has to be considered.

Analysis of Effluents and Receiving Waters Arising from the Coal Fired Kasimpur Thermal Power Plant

1983 ◽  
Vol 15 (10) ◽  
pp. 227-236 ◽  
Author(s):  
Mohammad Ajmal ◽  
Azhar A Nomani ◽  
Mujahid A Khan
Keyword(s):  
Power Plant ◽  
Thermal Power Plant ◽  
Thermal Power ◽  
Cooling Water ◽  
Chemical Properties ◽  
Oxygen Demand ◽  
Dry Weight ◽  
Total Alkalinity ◽  
Physico Chemical ◽  
Nitrite Nitrate

The waters of the upper Ganga canal, discharged cooling water and the machine washings of 530 MW Kasimpur coal fired thermal power plant were analysed for different parameters like colour, turbidity, pH, total alkalinity, total dissolved solids, chloride, sulphate, nitrite, nitrate, nitrate-ammonia, dissolved oxygen, biochemical oxygen demand and chemical oxygen demand. Metals zinc, lead, cadmium, iron, chromium, copper, nickel, cobalt and manganese were also determined in upstream, down stream, discharged cooling water, machine washings, sediment, plant and fish of the canal. The concentrations of Zn, Pb, Cd, Fe, Cr, Cu, Ni, Co and Mn in the upstream, downstream, cooling effluent and machine washings were found in the range 44.4-204, 1.33-26, 0.27-1.7, 49-208, 13.52-176. 11.5-79, 4.1-9, 4-8.1 and 42-68 µg/l; in the sediments 56.4-133, 1.22-28, 0.8-1.6, 9438-10595, 14.2-128, 13.6-15.0, 18.4-21, 7.3-16 and 320.7-392.2 µg/g; in the plants 21-25, 1.3-2.3, 0.05-0.08, 422-504, 3.5-11, 6.7-11.6, 3.3-7.9, 5.1-10.7 and 81-119 µg/g and in the fish 129.2-141.4, 2.1-3.82, 0.023-0.028, 234-242.1, 1.3-2, 7.8-11.3, 2.2-2.9, 2.6-3.0 and 108-114.6 ég/g on a dry weight basis. The sediments of the canal were analysed for pH, calcium carbonate, organic matter, potassium and phosphorus. In addition, the effects of influent and effluent water on the physico-chemical properties of soil, germination of seeds and growth pattern of the plants were observed but the results were found to be insignificant.

scholarly journals Comparison of Microstructure and Mechanical Properties of Induction and Vacuume Brazed Joint of Titanium Via Copper and Ag-Cu Eutectic Filler Metal / Mikrostruktura I Właściwości Mechaniczne Połączeń Tytanu Lutowanych Indukcyjnie I Próżniowo Z Użyciem Spoiwa Miedzianego I Eutektycznego Ag-Cu

2015 ◽  
Vol 60 (4) ◽  
pp. 2593-2598 ◽  
Author(s):  
M. Różański ◽  
D. Majewski ◽  
K. Krasnowski
Keyword(s):  
Mechanical Properties ◽  
Filler Metal ◽  
Chemical Properties ◽  
Metallographic Examination ◽  
Air Atmosphere ◽  
Microstructure And Mechanical Properties ◽  
Physico Chemical ◽  
Brazed Joints ◽  
Brazed Joint

This study presents the basic physico-chemical properties and describes the brazeability of titanium. The work contains the results of macro and microscopic metallographic examination as well as the results of strength-related tests of vacuum and induction brazed joints made of Grade 2 technical titanium using the Cu 0.99 and Ag 272 filler metal interlayers and F60T flux intended for titanium brazing in the air atmosphere.

Species diversity of keratinophilic fungi in various soil types

2012 ◽  
Vol 7 (2) ◽  
pp. 259-266 ◽  
Author(s):  
Justyna Bohacz ◽  
Teresa Korniłłowicz-Kowalska
Keyword(s):  
Species Diversity ◽  
Chemical Properties ◽  
Morphological Characters ◽  
Keratinophilic Fungi ◽  
Ecological Group ◽  
Natural Environments ◽  
Dead Animal ◽  
Physico Chemical ◽  
Chrysosporium Keratinophilum ◽  
Geophilic Dermatophytes

AbstractKeratinophilic fungi are a highly specialized, keratin-degrading ecological group. They live in natural environments, mostly in the keratinrich remains of dead animal in the soil. We investigated species diversity in four types of soils with different physico-chemical properties. The strain material was identified based on morphological characters. Different representatives of Chrysosporium and geophilic dermatophytes dominated depending on soil pH. Geophilic dermatophytes were represented by one species, Trichophyton ajelloi, and the Chrysosporium group was represented by Chrysosporium keratinophilum. The frequency of Trichophyton ajelloi increased with an increase in pH, and it reached the maximum in strongly acidic soil (podzol), unlike the Chrysosporium group. The frequency of Chrysosporium keratinophilum was positively correlated with the content of humus, nitrogen, CaCO3 and phosphorus in the soils.

Investigation of Physico-Chemical Properties and Microstructure of HA/316L Asymmetrical Functionally Gradient Biomaterial

2011 ◽  
Vol 239-242 ◽  
pp. 1062-1067 ◽  
Author(s):  
Jian Peng Zou
Keyword(s):  
Mechanical Properties ◽  
Hot Pressing ◽  
Phase Interface ◽  
Chemical Properties ◽  
Fracture Modes ◽  
Gradient Layer ◽  
Functionally Gradient ◽  
Physico Chemical ◽  
Two Phases

By using of hot pressing(HP) technique, HA/316L powder asymmetrical functionally gradient biomaterial (FGM) with 316L’s content changing as 100vol%→80vol%→60vol%→40vol%→20vol%→0vol% was prepared successfully. The results show obvious macroscopic gradient changes in the FGM. While the components change continuously in microcosmic, the interfaces among all gradient layers integrate tightly. The addition of 316L powder changes the fracture modes of the composites and improves their mechanical properties. HA contents in HA/316L biological FGM change regularly with different gradient layer, which is responding to the components design. Combining circumstance of phase interface is considerably well and both phase bite into each other at the interface. The two phases of HA and 316L powder dissolve into each other in some degree during hot pressing and the combining mechanism is dissolving behavior.

scholarly journals Rhodococcus as Biofactories for Microbial Oil Production

Molecules ◽  
2021 ◽  
Vol 26 (16) ◽  
pp. 4871
Author(s):  
Héctor M. Alvarez ◽  
Martín A. Hernández ◽  
Mariana P. Lanfranconi ◽  
Roxana A. Silva ◽  
María S. Villalba
Keyword(s):  
Molecular Mechanisms ◽  
Carbon Sources ◽  
Oil Production ◽  
Dry Weight ◽  
Industrial Wastes ◽  
Natural Environments ◽  
Microbial Oil ◽  
Qualitative And Quantitative ◽  
Physiological Properties ◽  
Wide Range

Bacteria belonging to the Rhodococcus genus are frequent components of microbial communities in diverse natural environments. Some rhodococcal species exhibit the outstanding ability to produce significant amounts of triacylglycerols (TAG) (>20% of cellular dry weight) in the presence of an excess of the carbon source and limitation of the nitrogen source. For this reason, they can be considered as oleaginous microorganisms. As occurs as well in eukaryotic single-cell oil (SCO) producers, these bacteria possess specific physiological properties and molecular mechanisms that differentiate them from other microorganisms unable to synthesize TAG. In this review, we summarized several of the well-characterized molecular mechanisms that enable oleaginous rhodococci to produce significant amounts of SCO. Furthermore, we highlighted the ability of these microorganisms to degrade a wide range of carbon sources coupled to lipogenesis. The qualitative and quantitative oil production by rhodococci from diverse industrial wastes has also been included. Finally, we summarized the genetic and metabolic approaches applied to oleaginous rhodococci to improve SCO production. This review provides a comprehensive and integrating vision on the potential of oleaginous rhodococci to be considered as microbial biofactories for microbial oil production.

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