centrifugation method
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Author(s):  
Aditya Rahma Mudhana ◽  
Anasthasia Pujiastuti

Tomatoes contain lycopene which is an antioxidant. Antioxidant preparations can be made in the form of a cream with components of an oil phase, a water phase and an emulsifier. Emulsifiers that can be used are triethanolamine (TEA) and stearic acid. This study aims to determine the effect of triethanolamine and stearic acid as emulsifiers on the physical quality and mechanical stability of tomatoes extract cream. The use of triethanolamine and stearic acid with a ratio of 2%:5%; 3%:10%; 4%:15%. The test are the physical characteristics of tomatoes extract cream included organoleptic, homogeneity, cream type, pH, viscosity, spreadability, adhesion, protection and mechanical stability using the centrifugation method. The results of the phytochemical screening of tomatoes extract were positive for triterpenoids. The test results of the three cream formulas are odorless, semi-solid form, light orange to white color, homogeneous, cream type M/A, pH 5.25 - 6.26; viscosity 5,376 cP - 14,370 cP, spreadability 4 - 5,067 cm, adhesion 4 - 11.6 seconds, protection power 2 - 5.2 seconds. The three cream formulas did not undergo phase separation. The higher concentration of TEA and stearic acid had an effect on viscosity, pH value, adhesion, dispersibility and protection, but had no effect on organoleptic, homogeneity, cream type, and stability. tomatoes extract cream with a concentration of TEA:stearic acid 2%:5% gave the best physical quality.


2021 ◽  
Author(s):  
Mikel Urrutikoetxea-Gutiérrez ◽  
Mónica S Montiel ◽  
Matxalen Vidal-Garcia ◽  
Miren Basaras ◽  
Ramón C Cancer ◽  
...  

Background: Fast diagnosis of bloodstream infections remains the most important challenge for clinical microbiologists. The introduction of the mass-spectrometry represents a breakthrough, although several methods are already commonly used for the direct identification from positive blood cultures we present a faster method (ultra fast) for Lytic anaerobic flasks. Methods: We compare the ultra-fast (UF) method with the extensively employed differential centrifugation method (DC) and both to routine identification after 18–24 h of incubation. UF and DC method correlation rates to the gold standard were calculated, and statistical significance was proved with the Z test. Results: UF performed better overall than DC, with this difference being statistically significant. This tendency was observed in every subanalysis.


2021 ◽  
Vol 2064 (1) ◽  
pp. 012105
Author(s):  
Nay Win Aung ◽  
M A Pugachevskii ◽  
A P Kuzmenko ◽  
Myo Min Than

Abstract The article discusses the results of ordering a composite of carbon nanoparticles (CNPs) coated copper oxide (CuO) on the silicon substrate by the electrophoresis method and, particles size and chemical composition have analyzed by Raman spectroscopy, an Atomic Force Microscope, and Scanning Electron Microscope. Carbon nanoparticles from Single-walled Carbon Nanotubes (SWCNTs) using the centrifugation method are applied by a pipette (by the drop method) on the silicon substrate with copper electrodes under the direct electric field to obtain CNPs-CuO nanocomposite films. It has been shown that carbon nanoparticles in solutions upon dispersion in an ultrasonic bath and subsequent centrifugation have a limiting particle size of 38 nm and CNPs solution can be controlled to obtain the nanocomposite films by the electrophoretic forces.


Materials ◽  
2021 ◽  
Vol 14 (15) ◽  
pp. 4181
Author(s):  
Paweł Droździel ◽  
Tetiana Vitenko ◽  
Viktor Voroshchuk ◽  
Sergiy Narizhnyy ◽  
Olha Snizhko

The efficient use of supplied energy is the basis of the discrete-impulse energy supply (DIES) concept. In order to explore the possibility of using DIES to intensify the hydromechanical processes, the emulsification of milk fat (homogenization of milk, preparation of spreads) and, in particular, the processing of cream cheese masses, were studied. Whole non-homogenized milk, fat emulsions, and cream cheese mass were the object of investigation. To evaluate the efficiency of milk homogenization, the homogenization coefficient change was studied, which was determined by using the centrifugation method, as it is the most affordable and accurate one. To provide the proper dispersion of the milk emulsion, six treatment cycles must be carried out under the developed cavitation mode in a static-type apparatus, here resulting in a light grain-like consistency, and exhibiting the smell of pasteurized milk. The emulsions were evaluated according to the degree of destabilization, resistance and dispersion of the fat phase. On the basis of the obtained data with respect to the regularities of fat dispersion forming in the rotor-type apparatus, the proper parameters required to obtain technologically stable fat emulsion spreads, possessing a dispersion and stability similar to those of plain milk creams, were determined. It was determined that under the DIES, an active dynamic effect on the milk globules takes place. The rheological characteristics of cheese masses were evaluated on the basis of the effective change in viscosity. The effect of the mechanical treatment on the structure of the cheese masses was determined. 


Author(s):  
T. Susilawati ◽  
W.O. Bustari ◽  
I.P.B. Crisara ◽  
Kuswati . ◽  
A.N. Huda ◽  
...  

Background: Productivity of existing cattles in Indonesia is necessarily to be increase to balance meat consumption in this country. Determination of offspring of certain sex can be obtained from Percoll gradient density centrifugation.The purpose of this research was to elucidate the proportion of male calves that can result from artificial insemination using single and double doses of sexed semen in Ongole crossbred cows. Methods: The sexed semen samples were obtained through Percoll gradient density centrifugation performed by the Artificial Insemination Center. The artificial insemination method adopted here was deep insemination. As much as 10 ml of BIO ATP® (Rheinvet) was injected in each cow before immediately insemination. Further, as much as 3 kg/day of additional feed was given over three days after insemination, with a protein level of about 12%. Result: Our results showed the proportion of Y-bearing sperm among non-sexed semen was 52.77% and among sexed semen, was 80.79%. Further, 54.17% of the non-sexed semen, 42.11% of the single-dose sexed semen and 78.95% of the double-dose sexed semen treatments yielded male calves.


NANO ◽  
2021 ◽  
pp. 2150074
Author(s):  
Bo Huang ◽  
Huichao Zhang

As heavy-metal-free alternatives to Cd- and Pb-containing semiconductor nanocrystals (NCs), ternary I–III–VI2 compounds NCs have been actively studied, especially the CuInS2 NCs. Recently, it has been found that thick ZnS shelling can greatly improve the photochemical stability of such NCs, which undoubtedly enhances their application potential although it is still limited by the development of synthetic methods. This paper provides a facile method for preparation of thick-shell CuInS2/ZnS NCs. The effects of reaction temperatures ([Formula: see text]C and [Formula: see text]C) and sulfur precursors (dodecanethiol and sulfur powder) on the shell overgrowth are discussed in detail. When low reaction temperature ([Formula: see text]C) and inactive sulfur precursor are used, the overgrowth of ZnS shell is considerably slow and raising temperature have a limited impact on the particles’ size. On the contrary, high reaction temperature and reactive sulfur precursor can effectively improve the overgrowth rate of ZnS shell, and then thick-shell CuInS2/ZnS NCs can be received. Furthermore, a high-speed centrifugation method is used to screen out product NCs with a relatively uniform size.


Author(s):  
Pawel Droździel ◽  
Tetiana Vitenko ◽  
Viktor Voroshchuk ◽  
Sergiy Narizhnyy ◽  
Olha Snizhko

The basis of the discrete-impulse energy supply (DIES) concept is the efficient use of supplied energy. The references describe in detail the general principles of DIES, examine the energy and thermodynamic aspects and the main mechanisms of intensification that can be initiated on the basis of this principle. DIES mechanisms conveniently can be divided into hard and soft ones. The former should be used to stimulate hydromechanical processes, and the latter to accelerate the processes of phase heat and mass transfer, or for the purpose of intensive mixing of multicomponent media. The authors have studied the possibility of using DIES to intensify the hydromechanical processes, in particular emulsification of milk fat (homogenization of milk, preparation of spreads), processing of cream cheese masses. Objects of research were whole non-homogenized milk, fat emulsions, cream cheese mass. In order to evaluate the efficiency of milk homogenization the homogenization coefficient change was studied, which was determined by centrifugation method as the most affordable and accurate one. Emulsions were evaluated according to the degree of destabilization, resistance and dispersion of the fat phase. The rheological characteristics of cheese masses were evaluated by the effective viscosity change.


Author(s):  
Natalia P. Fadeeva ◽  
Svetlana V. Saikova ◽  
Elena V. Pikurova ◽  
Anton S. Voronin ◽  
Yuri V. Fadeev ◽  
...  

In the work, sedimentation-stable sols of indium (III) and tin (IV) hydroxides were obtained by the Anion Resin Exchange Precipitation, which consists of the exchange reaction between the OH ions of the anion exchange resin and the anions of metal-containing solutions. The synthesized hydrosols were used to obtain conducting films of indium (III) In2O3 oxide and indium oxide doped with Tin In2O3: Sn, with a surface resistance of 4 kOhm/sq, thicknesses of 200–500 nm and a transparency of more than 85 %. The modes of applying precursors to glass substrates by the modified spray method and centrifugation method are selected. Films were studied using XRD, SEM, optical microscopy and spectrophotometry


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Annamaria Nigro ◽  
Annamaria Finardi ◽  
Marzia M. Ferraro ◽  
Daniela E. Manno ◽  
Angelo Quattrini ◽  
...  

AbstractMicrovesicles (MVs) are large extracellular vesicles differing in size, cargo and composition that share a common mechanism of release from the cells through the direct outward budding of the plasma membrane. They are involved in a variety of physiological and pathological conditions and represent promising biomarkers for diseases. MV heterogeneity together with the lack of specific markers had strongly hampered the development of effective methods for MV isolation and differential centrifugation remains the most used method to purify MVs. In this study, we analysed the capacity of the differential centrifugation method to isolate MVs from cell-conditioned medium using flow cytometry and TEM/AFM microscopy. We found that the loss of MVs (general population and/or specific subpopulations) represents a major and underestimate drawback of the differential centrifugation protocol. We demonstrate that the choice of the appropriate rotor type (fixed-angle vs swinging-bucket) and the implementation of an additional washing procedure to the first low-speed centrifugation step of the protocol allow to overcome this problem increasing the total amount of isolated vesicles and avoiding the selective loss of MV subpopulations. These parameters/procedures should be routinely employed into optimized differential centrifugation protocols to ensure isolation of the high-quantity/quality MVs for the downstream analysis/applications.


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