Academic literature on the topic 'Centrifugation speed'
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Journal articles on the topic "Centrifugation speed"
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Peterson, Brandon W., Prashant K. Sharma, Henny C. van der Mei, and Henk J. Busscher. "Bacterial Cell Surface Damage Due to Centrifugal Compaction." Applied and Environmental Microbiology 78, no. 1 (2011): 120–25. http://dx.doi.org/10.1128/aem.06780-11.
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ABSTRACTCentrifugal damage has been known to alter bacterial cell surface properties and interior structures, including DNA. Very few studies exist on bacterial damage caused by centrifugation because of the difficulty in relating centrifugation speed and container geometry to the damage caused. Here, we provide a simple, versatile method of analysis for describing the compaction of bacteria during centrifugation based on a proposed centrifugation coefficient,C. Values ofCcan be related to different bacterial cell surface properties. Changing the geometry of the centrifugation container or centrifugation speeds changed the value ofCsignificantly. Initial deposition rates ofStaphylococcus aureusATCC 12600 to a glass surface decayed exponentially from 4,217 to 1,478 cm−2s−1with increasingC, while the proportion of staphylococci with a zeta potential of around −15 mV decreased from 97 to 58%. These surface-sensitive parameters were used independently to derive a critical centrifugation coefficient (0.040), above which centrifugation was considered to impact the outcome of surface-sensitive experiments due to cell surface damage. The critical centrifugation coefficient could successfully predict staphylococcal cell surface damage, i.e., a significant change in initial deposition rate or zeta potential distribution, in 84% of all cases included here, whereas the centrifugation speed could predict damage in only 58% of all cases. Moreover, controlling the centrifugation coefficient within narrow limits over a series of experiments yielded 43% smaller standard deviations in initial staphylococcal deposition rates than with centrifugation at fixed speeds for replicate experiments.
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MEROLLA, M., M. A. NARDI, and J. S. BERGER. "Centrifugation speed affects light transmission aggregometry." International Journal of Laboratory Hematology 34, no. 1 (2011): 81–85. http://dx.doi.org/10.1111/j.1751-553x.2011.01360.x.
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Hasanah, Muslimah Uswatun, and Puspitasari Puspitasari. "The Effect Of Centrifugation Speed On The Results Of Urine Sediment Examination." Medicra (Journal of Medical Laboratory Science/Technology) 5, no. 2 (2022): 104–8. http://dx.doi.org/10.21070/medicra.v5i2.1668.
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The process of centrifugation in urine examination is very important because it can be used in the manufacture of urine sediment. The purpose of this study was to determine the effect of centrifugation speed on the results of urine sediment examination. Centrifugation speeds used were 3000 rpm, 3500 rpm, 4000 rpm, and 4500 rpm using pathological urine samples. The samples used were 32. The research method used was an experimental laboratory at the Pusura Yos Sudarso clinical laboratory in Surabaya. The results of the study with a speed of 3000 rpm obtained an average of erythrocytes = 6.63/LPB, leukocytes = 13.63/LPB, and epithelial = 10.50/LPB. At a speed of 3500 rpm the average value of erythrocytes = 7.63/LPB, leukocytes = 15.13/LPB, and epithelium 11.63/PLB. At a speed of 4000 rpm the average value of erythrocytes = 8.63/LPB, leukocytes = 17.75/LPB and epithelial = 13.50/LPB. At a speed of 4500 rpm the average value of erythrocytes = 9.63/LPB, leukocytes = 20.50/LPB, and epithelial = 15.38/LPB. The results of the statistical test One Way Anova obtained p-value results of 0.001 < (0.05) in erythrocyte cells, p-value results for leukocytes 0.025 < (0.05), and p-value results for epithelial cells 0.002 < (0.05) means that there is an effect on the centrifugation speed on the results of urine sediment examination.
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Tsujino, Tetsuhiro, Hideo Masuki, Masayuki Nakamura, et al. "Striking Differences in Platelet Distribution between Advanced-Platelet-Rich Fibrin and Concentrated Growth Factors: Effects of Silica-Containing Plastic Tubes." Journal of Functional Biomaterials 10, no. 3 (2019): 43. http://dx.doi.org/10.3390/jfb10030043.
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Compared with platelet-rich plasma, the preparation of platelet-rich fibrin (PRF) is simple and has not been overly modified. However, it was recently demonstrated that centrifugation conditions influence the composition of PRF and that silica microparticles from silica-coated plastic tubes can enter the PRF matrix. These factors may also modify platelet distribution. To examine these possibilities, we prepared PRF matrices using various types of blood-collection tubes (plain glass tubes and silica-containing plastic tubes) and different centrifugation speeds. The protocols of concentrated growth factors and advanced-PRF represented high- and low-speed centrifugation, respectively. Platelet distribution in the PRF matrix was examined immunohistochemically. Using low-speed centrifugation, platelets were distributed homogeneously within the PRF matrix regardless of tube types. In high-speed centrifugation, platelets were distributed mainly on one surface region of the PRF matrix in glass tubes, whereas in silica-coated tubes, platelet distribution was commonly more diffusive than in glass tubes. Therefore, both blood-collection tube types and centrifugal conditions appeared to influence platelet distribution in the PRF matrix. Platelets distributed in the deep regions of the PRF matrix may contribute to better growth factor retention and release. However, clinicians should be careful in using silica-coated tubes because their silica microparticles may be a health hazard.
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Fallatah, Majed Hashem, Aaied Falah Al Otaibi, Randa Rajallah Aljohani, Waad Jamal Ghabban, and Alaa Ali Alshehri. "Evaluation of Centrifugation Technique and the Effect of Centrifugation Condition on the Laboratory Samples." JOURNAL OF HEALTHCARE SCIENCES 04, no. 12 (2024): 1003–9. https://doi.org/10.52533/johs.2024.41248.
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Centrifugation is a critical laboratory technique used to separate components within a mixture based on density differences. The efficiency and reliability of this process depend on the precise control of variables such as speed, time, temperature, and rotor design. Improper centrifugation settings can compromise sample integrity, leading to analytical inaccuracies. High-speed centrifugation, while effective for rapid separation, often imposes mechanical stress on samples, resulting in hemolysis or cellular damage. Time duration is equally significant, as insufficient centrifugation can cause incomplete separation, while prolonged exposure may induce thermal stress and biochemical degradation. Temperature control plays a pivotal role, particularly for temperature-sensitive biomolecules like enzymes, nucleic acids, and proteins. Unregulated temperatures during high-speed centrifugation can denature proteins and degrade nucleic acids, affecting their utility in downstream applications such as diagnostics and molecular biology. Automated centrifuges equipped with programmable cooling systems have proven effective in mitigating these risks. Centrifugation protocols require customization based on sample type. Blood, urine, and cellular samples exhibit distinct sensitivities to centrifugal force and duration, necessitating tailored approaches. Specialized techniques, such as density-gradient centrifugation, enhance separation precision for applications like exosome isolation. Recent innovations in centrifuge technology, including programmable speed ramps and advanced rotor designs, have significantly improved the reproducibility and reliability of centrifugation processes. Standardization of centrifugation protocols is essential to ensure consistency in laboratory results. Advances in centrifuge design and optimization strategies have enabled better preservation of sample integrity across diverse applications. These developments highlight the need for continuous refinement of protocols to accommodate emerging diagnostic and research requirements, ensuring high-quality outcomes in both clinical and experimental settings.
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Linares, Romain, Sisareuth Tan, Céline Gounou, Nicolas Arraud, and Alain R. Brisson. "High-speed centrifugation induces aggregation of extracellular vesicles." Journal of Extracellular Vesicles 4, no. 1 (2015): 29509. http://dx.doi.org/10.3402/jev.v4.29509.
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Fretwurst, Tobias, Sebastian Grunert, Fabian Duttenhöfer, and Richard Miron. "Platelet Rich Fibrin - Das Low-Speed Centrifugation Concept." ZWR - Das Deutsche Zahnärzteblatt 126, no. 04 (2017): 166–70. http://dx.doi.org/10.1055/s-0043-105256.
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Mateyko, G. M., and M. J. Kopac. "PART II: ISOPYKNOTIC CUSHIONING DURING HIGH-SPEED CENTRIFUGATION." Annals of the New York Academy of Sciences 105, no. 4 (2006): 219–85. http://dx.doi.org/10.1111/j.1749-6632.1963.tb42980.x.
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Sorber, Laure, Karen Zwaenepoel, Julie Jacobs, et al. "Circulating Cell-Free DNA and RNA Analysis as Liquid Biopsy: Optimal Centrifugation Protocol." Cancers 11, no. 4 (2019): 458. http://dx.doi.org/10.3390/cancers11040458.
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The combined analysis of circulating cell-free (tumor) DNA (cfDNA/ctDNA) and circulating cell-free (tumor) RNA (cfRNA/ctRNA) shows great promise in determining the molecular profile of cancer patients. Optimization of the workflow is necessary to achieve consistent and reproducible results. In this study, we compared five centrifugation protocols for the optimal yield of both cfDNA/ctDNA and cfRNA/ctRNA. These protocols varied in centrifugation speed, ambient temperature, time, and number of centrifugation steps. Samples from 33 participants were collected in either BD Vacutainer K2EDTA (EDTA) tubes or cell-free DNA BCT® (Streck) tubes. cfDNA concentration and fragment size, and cfRNA concentration were quantitated in all samples by digital droplet PCR (ddPCR) and quantitative PCR (qPCR). The KRAS-mutated ctDNA and ctRNA fraction was determined via ddPCR. In EDTA tubes, the protocol generating both plasma and platelets was found to produce high quality cfDNA and cfRNA concentrations. Two-step, high-speed centrifugation protocols were associated with high cfDNA but low cfRNA concentrations. High cfRNA concentrations were generated by a one-step, low-speed protocol. However, this coincided with a high amount of genomic DNA (gDNA) contamination. In Streck tubes, two-step, high-speed centrifugation protocols also generated good quality, high cfDNA concentration. However, these tubes are not compatible with cfRNA analysis.
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Kamila, Nadya Permata, and Wisnu Broto. "The Effect of Mixing Red Coconut and Green Coconut on The Manufacture of VCO Using The Centrifugation Method." Journal of Applied Food Technology 9, no. 2 (2022): 30–33. http://dx.doi.org/10.17728/jaft.14892.
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Virgin coconut oil (VCO) can be made from several types of coconuts by using several techniques that potentially result ini clear colour, distinct coconut smell, and long shelf life. In this study, centrifugation method was used in the manufacture of VCO by using green coconuts and red coconuts with a ratio of 1:1 and 2:1. This study aims to determine the ratio of the best raw materials and determine the % yield. This study uses factorial design and a quicker method for calculating the effect of the process variable with eight runs (experimental). The most influential variable was the centrifugation time, where the optimum yield was 35 minutes, the centrifugation speed was 800 rpm, and the ratio of green coconut and red coconut was 4:3. yielded 56.8% yield. It can be concluded that the best way to produce VCO with a high yield is to use a centrifugation method with a ratio of green to red coconuts of 4:3, a centrifugation time of 35 minutes, and a centrifugation speed of 800 rpm.
Dissertations / Theses on the topic "Centrifugation speed"
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Pedro, Mara Simões. "Platelet-rich fibrin membranes resistance to traction comparing A-PRF versus A-PRF+." Master's thesis, 2021. http://hdl.handle.net/10400.14/34572.
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Objetivos: O presente estudo teve como objetivo comparar as propriedades
mecânicas de resistência à tração e estrutura entre as membranas produzidas
por A-PRF (Advanced- Platelet Rich Fibrin) e A-PRF+ (Advanced-Platelet Rich
Fibrin+).
Materiais e métodos: Recorrendo à colheita de sangue de um dador saudável
sem história de uso de anticoagulantes ou imunossupressores, realizou-se a
preparação das membranas seguindo as indicações protocolares definidas na
literatura para A-PRF e A-PRF+. De um N=16/grupo, 13 membranas de A-PRF
e 12 de A-PRF+ foram submetidas ao teste de tração, para a obtenção de valores
referentes à tração máxima e tração média. Os dados obtidos foram analisados
estatisticamente com o teste t não pareado. Após avaliação desta variável, as
membranas foram observadas em MEV (Microscopia Eletrónica de Varredura).
Resultados: Foram obtidos em relação à tração máxima, 0.0020 N.mm-2 para o
A-PRF e 0.0022 N.mm-2 para A-PRF+. Relativamente à tração média, A-PRF
obteve 0.0012 N.mm-2
, enquanto o A-PRF+ obteve 0.0015 N.mm-2
(p˂0,01). Nas
observações de superfície com MEV, A-PRF+ mostrou ser o concentrado
plaquetário mais poroso, com maior abundância de fibras e preservação celular.
Conclusão: Este estudo permitiu concluir que o protocolo A-PRF+ foi capaz de
produzir membranas com valores de tração máxima superiores aos obtidos pelo
A-PRF, sendo os resultados indicativo de que o protocolo apresentou
membranas com maior resistência e capacidade elástica ao serem tracionadas
por duas forças opostas. A este fenómeno acrescenta-se a arquitetura
demonstrada na matriz de A-PRF+ e as propriedades biológicas otimizadas
descritas na literatura.<br>Purpose: This study aimed to formulate a comparison of the mechanical
properties of tensile strength and structural organization between membranes
produced by A-PRF (Advanced Platelet-Rich Fibrin) and A-PRF+ (Advanced
Platelet-Rich Fibrin+).
Materials and Methods: Blood was collected from a healthy donor with no
history of anticoagulant or immunosuppressant use, the membranes were
prepared following the protocol indications defined in the literature for A-PRF and
A-PRF+. From an N=16 for each protocol, 13 membranes of A-PRF and 12 of APRF+ were submitted to the traction test, evaluating maximum and average
traction. Data was statistically analyzed using the unpaired t test. Membranes
were then carefully observed in SEM (Scanning Electron Microscopy).
Results: For maximum traction were obtained 0.0020 for A-PRF and 0.0022 for
A-PRF+. Regarding the average traction, A-PRF scored 0.0012 while A-PRF+
obtained 0.0015 (p=0.01 unpaired t-test). Surface morphology observations with
SEM, A-PRF+ showed to be the most porous platelet concentrate, with greatest
fiber abundance and cell preservation.
Conclusion: This study allowed to conclude that A-PRF+ protocol was able to
produce membranes with higher maximum traction results than those found for
A-PRF, indicating that the protocol with low centrifugation time, presented
membranes with better viscoelastic strength when they are stretched by two
opposed forces. To this phenomenon is added the architecture demonstrated in
the A-PRF+ matrix and the optimized biological properties described in literature.
A-PRF+, by the view of the developed findings in this work, a better option
compared to A-PRF.
Keywords: “Platelet-Rich Fibrin”, “Viscoelastic”, “Tensile Strength”, “Rupture”,
“Porosity”, “Low-Speed Centrifugation Concept”.
Book chapters on the topic "Centrifugation speed"
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Choukroun, Joseph, and Shahram Ghanaati. "Introducing the Low-Speed Centrifugation Concept." In Platelet Rich Fibrin in Regenerative Dentistry: Biological Background and Clinical Indications. John Wiley & Sons, Ltd, 2017. http://dx.doi.org/10.1002/9781119406792.ch3.
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Doyle, I. R., R. L. Ryall, and V. R. Marshall. "The Effect of Low-Speed Centrifugation and Millipore Filtration on the Urinary Protein Content." In Urolithiasis. Springer US, 1989. http://dx.doi.org/10.1007/978-1-4899-0873-5_183.
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Wetzig, Tony, Andreas Baaske, Sven Karrasch, Steffen Dudczig, and Christos G. Aneziris. "Cleanness of Molten Steel—Active and Reactive, Exchangeable Filter Systems for the Continuous Casting of Steel." In Multifunctional Ceramic Filter Systems for Metal Melt Filtration. Springer International Publishing, 2024. http://dx.doi.org/10.1007/978-3-031-40930-1_29.
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AbstractThe filtration of steel melts in the continuous casting of steel is of special interest in order to meet the ever-increasing purity requirements regarding the metal’s purity. Due to the high mass flow and the high casting duration, the application of in-built filters in the tundish system is rather challenging, especially regarding the filter capacity. In the framework of this contribution, a new concept involving the immersion of filters into the steel melt from above the tundish was investigated. This approach allows for the flexible exchange of used filters without interruption of the underlying process. At the Institute of Ceramics, Refractories and Composite Materials, carbon-bonded alumina filters on the basis of established slurry compositions and modified replication techniques were scaled up for the industrial application in continuous casting of steel. The best property profile was observed for a triple coating approach based on centrifugation, dip coating and spray coating. In the tundish of a steel casting simulator, a lab-scale casting test was conducted in order to check the thermos-mechanical behavior of the filter in contact with molten steel. After the successful evaluation in lab scale, the filters were tested in industrial trials in cooperation with the company thyssenkrupp Steel Europe AG. A ladle casting with immersed filter lasted approximately 45 min with a static casting speed of 8 to 10 t/min and a melt temperature of above 1550 °C. The filters were analyzed for inclusions and potential damage at the Institute of Ceramics, Refractories and Composite Materials. Dense clogging layers on the filter surface were identified as in-situ layers as usually observed in lab-scale steel casting simulator tests in consequence of reactive filtration effects. Furthermore, inclusion clusters which were removed at the filter bottom due to the direct inflow in consequence of the buoyancy were observed as signs of active filtration. A further alternative to foam filters is presented by gel-cast spaghetti filter structures with mechanically robust full-strut structure. In the subproject T01K, the gel casting process was optimized in order to realize the necessary upscaling of the components. With the aid of alginate-based gel casting, spaghetti filter with organized lattice structures were manufactured and tested. Steel casting simulator trials showed favorable behavior in contact with the melt.
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Marcoty, Christian, Ernst Heinen, Nadine Antoine, Rikiya Tsunoda, and L. J. Simar. "Rapid and Selective Isolation of Follicular Dendritic Cells by Low Speed Centrifugations on Discontinuous BSA Gradients." In Advances in Experimental Medicine and Biology. Springer US, 1993. http://dx.doi.org/10.1007/978-1-4615-2930-9_71.
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Roth, Hans, and David Rickwood. "Centrifuges and rotors." In Preparative Centrifugation. Oxford University PressOxford, 1992. http://dx.doi.org/10.1093/oso/9780199632084.003.0002.
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Abstract Centrifuges can be classified on the basis of a number of different criteria. However, centrifuges are usually classified on the basis of their speed since this is a fairly good indicator of the centrifugal force (RCF) which can be generated by the machine and hence also indicates the range of possible applications that the centrifuge can be used for. Table 1 gives a summary of some of the principal classes of centrifuge, namely low-speed, high-speed, and ultracentrifuge. While these classes used to be quite distinct, over the years the boundaries have become somewhat more blurred in terms of the size, costs, and applications of the different machines. The primary interest of the user is simply an answer to the question ‘what can I use it for?’. The answer to this question is more complicated than it might seem. As an example, plasmid DNA can be prepared on isopycnic CsCl-ethidium bromide gradients (see Section 3.3.1 of Chapter 4) using one of the high-performance high-speed machines generating 100 000g. However, using such machines gradients need to be centrifuged for at least 30 h while using an ultracentrifuge the same isolation could be done in 2-5 h depending on the type of rotor used. Hence the time available to the researcher can also be a crucial factor in choosing the type of centrifuge for a particular application.
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Mansencal, Rachel, John F. Kadla, and Jennifer L. Braun. "Glycogen." In Polymer Data Handbook. Oxford University PressNew York, NY, 2009. http://dx.doi.org/10.1093/oso/9780195181012.003.0032.
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Abstract Functions Biological function restricted to source of energy. Principal food-reserve materials in animals. Found in cells of vertebrates and invertebrates. No commercial use. Extraction Extraction with hot concentrated alkali. But extensive degradation. Milder extraction with cold trichloroacetic acid solution, dimethyl sulfoxide, or water-phenol mixtures. Purification After extraction, redissolution in distilled water; low speed centrifugation (100 g); precipitation with excess ethanol; high speed centrifugation (1,500 g).
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Sano, Yoh, Ryoy A. Niki, Kaoru Kohy Ama, and Katsuyoshi Nishinari. "Turbidity study of casein micelles." In Gums and stabilisers for the Food industry 6. Oxford University PressOxford, 1992. http://dx.doi.org/10.1093/oso/9780199632848.003.0064.
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Abstract Casein micelles of different sizes were prepared by centrifugation and the distribution of particle sizes was analyzed by turbidity measured with a conventional visible spectrophotometer. The molecular weight and the diameter of casein micelles determined by turbidity correlated fairly well to the centrifugation speeds. The higher the speed the smaller the casein micelles. Aggregation and gelation of casein micelles in the presence of rennet was studied as a function of micelle sizes. The smallest micelle had the shortest gelation time, the largest rate constant and also the largest saturated elastic modulus of three size micelles.
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Lokhande, Yogita. "Centrifuge." In Bio Instrumentation: Tools and Techniques. Iterative International Publishers, Selfypage Developers Pvt Ltd, 2024. http://dx.doi.org/10.58532/nbennurbich2.
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Centrifugation is a process used to separate particles from a solution based on their size, shape, density, medium viscosity and rotor speed using centrifugal force. The denser particles tend to move along the length of the tube to a greater radius of rotation, displacing the lighter particle to the proximal end. It is carried out with an apparatus called centrifuge. A centrifuge is a device for separation of microbes from the suspended fluid using centrifugal force or gravitational force. The word centrifugal force isoriginated from Latin word centrum, meaning ―center‖, and fugere, means ―to flee. The speed of centrifuge is denoted as rpm or revolutions per minute.
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Harding, Stephen E., and Donald J. Winzer. "Sedimentation velocity analytical ultracentrifugation." In Protein-Ligand Interactions: hydrodynamics and calorimetry. Oxford University PressOxford, 2000. http://dx.doi.org/10.1093/oso/9780199637492.003.0004.
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Abstract There has been a general misconception amongst biochemists that the analytical ultracentrifuge does not provide an absolute means of molecular mass determination and hence of the characterization of interaction phenomena. This has arisen from a lack of awareness about the difference between the two types of experiment that can be performed in the analytical ultracentrifuge. (a) Sedimentation velocity: an experiment performed at sufficiently high speed for the centrifugation of solute away from the centre of rotation to be monitored as the rate of movement of a sedimenting boundary. For a given rotor speed, solvent viscosity and solvent density the rate of migration depends upon the overall size and shape of the macromolecule or macromolecule ligand complex.
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Mercader Ruiz, Jon, Maider Beitia, Diego Delgado, et al. "New Formulations of Platelet-Rich Plasma: The Relevance of Extraplatelet Molecules." In Wound Healing - New Frontiers and Strategies [Working Title]. IntechOpen, 2024. http://dx.doi.org/10.5772/intechopen.1004699.
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Platelet-rich plasma (PRP) is a biological product with regenerative capacity. It is used in different fields of medicine such as traumatology, dentistry and dermatology, among others. Classically, PRP has been obtained by centrifugation, which generates a plasma enriched in platelets and their components compared to basal levels. However, this process does not enrich all the biomolecules present outside the platelets. Recently, different collection systems have been developed based on different processes such as filtration, sedimentation, ultrasound, microfluidics or water absorption. These systems often provide a more efficient collection in terms of enrichment or speed of collection. Importantly, some of them also favor the enrichment of extraplatelet components. This is potentially an advantage over other systems, given that extraplatelet factors such as IGF-1 or HGF have been reported to play a key role in contributing to the regenerative capacity of PRP.
Conference papers on the topic "Centrifugation speed"
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Haibo Yu, Wen J. Li, Yanli Qu, et al. "Purification of SWNTs using high-speed centrifugation." In 2008 3rd IEEE International Conference on Nano/Micro Engineered and Molecular Systems. IEEE, 2008. http://dx.doi.org/10.1109/nems.2008.4484390.
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Almorihil, Jawaher, Ahmed Alsmaeil, Ziyad Kaidar, and Abdulkareem AlSofi. "Produced Water Quality: Uncovering the Effects of Centrifugation for Water and Chemical Floods Using a Dispersion Analyzer." In SPE/IATMI Asia Pacific Oil & Gas Conference and Exhibition. SPE, 2021. http://dx.doi.org/10.2118/205534-ms.
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Abstract A second stage of gravity settling with the addition of demulsifiers or clarifiers is commonly used in processing plants to further treat the separated produced water. In previous work, we demonstrated gravity settling lower efficiency in removing oil carryover from produced water compared to other processing techniques. Both centrifugation and filtration were found to significantly improve the separated water quality. In this work, we focus on centrifugation and further evaluate its efficiency in improving the quality of separated water for both water and chemical floods, specifically surfactant/polymer (SP) flooding. Samples were firstly prepared to imitate the separation plant projected feed and operations. Synthetic representative brines were prepared and used with dead crude oil to prepare the oil/water emulsions. Emulsion separation was conducted at different temperatures, as well as different concentrations of SP, and the demulsifier. The kinetics and efficiency of separation were thoroughly studied over two stages of separation: primary gravity settling and secondary centrifugation. We performed gravitational separation using bottle tests in order to firstly obtain the separated produced water for use in secondary water treatment studies and to secondly further investigate gravity settling kinetics and efficiency. Water quality, in terms of oil content, was then assessed through solvent extraction and UV analyses. Samples of the produced water separated by the primary gravity settling were then exposed to secondary centrifugation. Centrifugation was performed at different rotational speeds using a dispersion analyzer. Light transmission evolution in space and time was used to study kinetics, efficiency and mechanisms of secondary centrifugation. The results reconfirmed that a single-stage gravity settling is not sufficient to reduce oil carryover to acceptable levels for disposal and re-injection into oilfields. Secondary centrifugation yielded clear and significant improvement in water quality even in the presence of EOR chemicals. With centrifugation, the separation efficiency was a function of the rotational speed. Higher rotational speeds resulted in higher creaming velocities and faster separation. In addition, creaming velocities indicated that higher temperatures yield favorable effects on oil droplets migration and separation rates. This is possibly due to the lower density and larger bouncy at higher temperatures. Based on these results, we conclude that secondary centrifugation is very efficient and effective in improving the quality of separated water. In terms of the effects of investigated EOR formulations, SP addition caused minor but manageable reduction in separated water quality at a level that would not harm conventional disposal practices.
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Chuan He and Jie Chen. "Study of interactions between cells and microbubbles in high speed centrifugation field for biomolecule delivery." In 2014 36th Annual International Conference of the IEEE Engineering in Medicine and Biology Society (EMBC). IEEE, 2014. http://dx.doi.org/10.1109/embc.2014.6944237.
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Fatimah, Siti, Marisa Asrietd Hafied, Putu Ayu Yuliani Indiasih, et al. "Amylose Isolation of Cassava Starch with the Combination of High Shear Mixer and Centrifugation Treatment to Improve the Quality of Resistant Starch Type 3 (RS-3) Products." In 4th International Seminar on Fundamental and Application of Chemical Engineering. Trans Tech Publications Ltd, 2024. http://dx.doi.org/10.4028/p-xj9zas.
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Cassava starch is a common food ingredient that has a high carbohydrate content. It can be modified into resistant starch type 3 (RS-3) that has lower glycemic index. The common production of RS-3 includes gelatinization to free the amylose from the granule structure, then followed by cooling to induce retrogradation. The granule structure of cassava starch resists the structure disintegration so that it is unable to produce high resistant starch content in the retrogradation process. In this study, High Shear Mixing (HSM) was used to help the gelatinization process to provide cassava starch structure disintegration. The centrifugation was carried out to separate the low free-amylose and high free-amylose liquid layers. This paper examines the relationship between the effect of variations in rotational speed (rpm) of HSM on the amount of resistant starch as a percentage of dietary fiber. A 1:20 starch-water suspension was processed using an HSM with rotational speeds of 9.000, 10.000, 11.000, and 12.000 at a temperature of 95°C for 15 minutes. After the stirring process, the water starch suspension was separated by centrifugation for 30 minutes. Then the samples were cooled in the refrigerator for 24 hours, then dried under freeze-drying method. The product that has been obtained is then analyzed by Total Dietary Fiber (TDF), amylose, and carbohydrate analysis. From the analysis of the result, this method can increase the TDF content of the product up to 14,66% at 12.000 rpm.
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Ali, Farhan, Yazan Mheibesh, Andrea Valori, Mohammed Al-Hamad, and Wael Abdallah. "Innovative Wellsite Porosity Analysis of Tight Cuttings by NMR." In International Petroleum Technology Conference. IPTC, 2024. http://dx.doi.org/10.2523/iptc-23297-ms.
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Abstract Knowledge of petrophysical parameters of a reservoir plays a significant role in reservoir formation evaluation. Most of the current information comes from downhole logging or special core analysis after acquiring reservoir core samples. Drill rock cuttings, however, are available continuously over the entire depth of the drilled well. Such cuttings can be used to obtain petrophysical data which can add a significant value to formation evaluation while drilling the well. In the current study, we introduce a workflow to accurately obtain porosity from irregular shaped and small size cuttings using nuclear magnetic resonance (NMR). A set of 9 drill cuttings were washed-out to remove the mud contamination, sieved in a sand-shaker, and then 25-50 g of each drill cuttings samples were collected for the particle size above 1 mm. The cuttings were stacked before they were centrifuged at elevated speeds, and the produced reservoir fluids were monitored. NMR was used to measure the porosity of the cuttings. However, the main uncertainty in such measurement was always the presence of fluids on the outer surface of the cuttings, making it very difficult to separate or distinguish from the pores’ fluids. Therefore, an additional step was implemented as part of this study, to overcome such difficulties. The stacked rock cuttings were centrifuged, to significantly remove the excess fluids at the cuttings surface, allowing accurate determination of the total porosity. Using the cuttings particle size and the centrifuge arms-length, a threshold capillary pressure value was obtained. At such threshold pressure value, only the excess fluids are removed, without displacing any of the fluids from the pores. It has been observed that only minimal pressure or centrifugal speed is needed to remove the excess water, upon investigation this speed was found to be 730 RPM which was equivalent to 0.016 psi. NMR measurements were performed before and after centrifugation, a clear differentiation in the signal was observed. The measured NMR porosity at the end of centrifugation cycle was found to correlate well with the measured porosity from the reservoir.
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Bandyopadhyay, Madhurima, Supratim Ghosh, and Michael Nickerson. "Extraction and Characterization of Minimally Processed Native Faba Bean (Vicia Faba) Protein Using Mild Fractionation." In 2022 AOCS Annual Meeting & Expo. American Oil Chemists' Society (AOCS), 2022. http://dx.doi.org/10.21748/fyfw1292.
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Pulse proteins are known to be high in protein and have good emulsifying properties. However, to optimize their performance as an emulsifier, the proteins need to be isolated in a manner to preserve their functional attributes. The most common commercial process to extract protein isolates from pulses such as faba bean (Vicia faba) is by alkaline extraction followed by isoelectric precipitation. However, this method relies on high pH (9-10) and spray drying, which can potentially denature the protein to alter its functionality. The present research aimed to extract native faba bean proteins from the flour using a mild aqueous fractionation and then characterize their structure, composition and functionality. The mild process will extract most likely more water-soluble albumin proteins, which would give different functionality. Faba bean flour (10% w/w) was dissolved in deionized water and centrifuged at different conditions by varying the speed (3000 and 4000 rpm) and duration (1.5 – 3.5 min). The extraction yield and purity of the proteins could be tailored by controlling centrifugal forces. Protein yield was found to decrease with an increase in time at a constant centrifugation speed. The soluble fraction obtained by centrifugation at 3000 rpm showed significantly lower interfacial tension for the samples centrifuged for a longer time duration. SDS PAGE analysis of the mildly fractionated soluble fraction revealed the presence of more albumin proteins compared to the globulin proteins. The data obtained in terms of protein composition, yield, purity, denaturation enthalpies and interfacial tension paved the way to understand the effect of the mild fractionation process on the efficiency of the minimally processed protein-rich fraction in emulsion stabilization.
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Oughanem, Rezki, Thomas Gumpenberger, Jean Grégoire Boero-Rollo, et al. "A Core Flood Test-Program Performed with a Pilot-Skid to Quantify the Permeability Decline Induced by Real Treated Produced Waters Also Containing Degraded Polymer or Not." In Abu Dhabi International Petroleum Exhibition & Conference. SPE, 2021. http://dx.doi.org/10.2118/207633-ms.
Full textAbstract:
Abstract A water treatment pilot skid called WaOω has been developed by TotalEnergies to test the efficiency of the centrifugation technology in treating the produced water containing back produced polymer. In case of success, this technology would be implemented on field and the water quality targeted by the technology must allow re-injecting the treated produced water in matrix flow regime for pressure maintain and sweep efficiency. The same interest was expressed by OMV and a partnership project has been built. It was also agreed that OMV builds a second pilot skid called PRT that allows carrying out core flood tests onsite to assess the formation damage and related permeability decline that could be induced by the treated produced water. Both pilot skids have been implemented, connected to each other, and tested during more than one year on the OMV's Matzen oil field nearby Vienna where degraded polymer is already back produced by wells and present in the produced water. More than seventy core flooding tests have been performed in different centrifugation conditions in terms of speed and water qualities, some of them on high permeable sand packs representing the field targeted by TotalEnergies and some others on consolidated sandstone samples of lower permeability representing OMV reservoirs. The effect of adding fresh polymer to the treated produced water for EOR purposes has also been investigated. Some complementary core flood tests have also been performed in TotalEnergies labs using reconstituted sand packs and produced waters with and without polymer to understand the contribution of the degraded polymer alone, the produced water quality alone and both to understand the formation damage and some uncommon results observed with the PRT pilot skid. Core flood tests data often obtained on long injection periods revealed of a high quality, reliable and reproducible. They also showed that even if centrifugation seems to be a good technology, the very clean and transparent water that it delivered induced surprisingly some core permeability declines the origin of which would be discussed in this paper. However, it was clearly established that the presence of degraded polymer has a cleaning effect and limits the formation damage induced by the produced water injected on cores if the Total Suspended Solids in the treated water remains at an acceptable level. Adding fresh polymers limited even more the formation damage because their cleaning effect is more pronounced than with degraded polymer.
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Morhard, Bernd, Constantin Paschold, Thomas Lohner, and Karsten Stahl. "Power Loss and Damage Behavior of Gears Operating Under Loss of Lubrication." In ASME 2023 International Design Engineering Technical Conferences and Computers and Information in Engineering Conference. American Society of Mechanical Engineers, 2023. http://dx.doi.org/10.1115/detc2023-111108.
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Abstract Geared turbofans need to withstand loss of lubrication due to inevitable off-design conditions. Additionally, loss of lubrication specifications that have to be fulfilled are getting stricter. For a loss of lubrication event, today’s geared turbofans are equipped with secondary oil supply systems. Their omission would reduce space and weight, and consequently, carbon emissions. However, this requires geared transmissions to withstand loss of lubrication events. In order to enable this, knowledge of the power loss and damage behavior of gears under loss of lubrication is required first. In this study, power loss and bulk temperature measurements of test gears under loss of lubrication on a FZG gear efficiency test rig are presented. Hertzian pressures in the pitch point up to 1723 N/mm2, and circumferential speeds up to 20 m/s were considered. The experimental results show the characteristics of increasing power loss and bulk temperatures under loss of lubrication depending on load and speed. At moderate operating conditions, no damage occurs within 20 seconds under loss of lubrication, whereas a load increase results in slight scuffing, and a speed increase results in severe scuffing. Oil centrifugation has a strong effect on the loss of lubrication performance. Additional experiments under minimum quantity lubrication demonstrate the impact of the remaining oil on the survivability of gears facing loss of lubrication.
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Fitriyani, L. "Biosurfactant Addition into Solvent Extraction Process of Oily Contaminated Solid Waste." In Digital Technical Conference. Indonesian Petroleum Association, 2020. http://dx.doi.org/10.29118/ipa20-o-435.
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Solvent extraction has been used in industry or many purposes for years, including to recover oil at contaminated soil. Certain solvents and temperature ranges have been chosen to increase the oil recovery rate of extraction process. The Study observed the implementation of biosurfactant at the extraction process to perform reduction of total petroleum hydrocarbon (TPH) concentration of oily contaminated soil. In order to optimize TPH removal, extraction were conducted for multiple stages. Biosurfactant extraction result were also compared to solvent extraction process which acetone and toluene have been selected to extract oil content from contaminated soil by using solvent extraction process. The combination treatments with biosurfactant were also involving variety of centrifugation process with 1000 rpm (1570 g) operational speed. Duration of treatment process was 10 minutes with some variations of solid to solvent ratio. During the experiments comparison result between varies treatment process provides alternatives to treat oily contaminated soil by using extraction process. Compatibility among solvents, biosurfactants, types of oily contaminated solid waste were also observed to seek possibility on large scale of treatment process implementation both insitu at the contaminated site and exsitu at integrated waste treatment facility.
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Howard, M. A., M. Coghlan, and B. G. Firkin. "EFFECT OF ELASTASE INDUCED CLEAVAGE OF VON WILLEBRAND FACTOR (vWf) ON ITS STRUCTURE AND FUNCTION." In XIth International Congress on Thrombosis and Haemostasis. Schattauer GmbH, 1987. http://dx.doi.org/10.1055/s-0038-1644091.
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A proteolytic product of vWf termed fast migrating protein (vWf:FMP) has been identified using crossed immunoelectrophoresis (CIE) in normal serum and in the plasma from patients with disseminated intravascular coagulation (DIC). A fragment of vWf antigen (vWf:Ag) migrating to a similar position on CIE as vWf:FMP results from digestion of vWf:Ag with polymorphonuclear cells (PMNC). Since parallels exist between the conditions for generation of vWf:FMP by PMNC and elastase release by these cells the effect of purified elastase from porcine pancrease on vWf was investigated.VWf was purified from plasma using polyethylene glycol, ammonium sulphate and zinc acetate precipitation, high speed centrifugation and elution from column of Sepharose 4B-CL. A fraction rich in vWf was radiolabelled with 125-Iodine to spike the purified preparation of vWf in order to increase the sensitivity of the protein detecting systems.A mixture of radiolabelled and non-labelled purified vWf was incubated with elastase at concentrations ranging from 2.5 to 40 U/ml for periods of 0-48 hours. Modifications of the structure were assessed by SDS-agarose multimeric analysis, SDS-polyacrylamide electrophoresis and CIE. Alterations of function were quantitated by antigen levels, ristocetin (RCof) and botrocetin (BCoF) cofactor assays and a binding assay to fixed washed platelets in the presence of ristocetin or botrocetin.These investigations show, 1. all but the highest molecular weight multimers of vWf are present when elastase has cleaved vWf such that no intact 240K subunit is present. 2. an intact 240K subunit is not essential for RCoF and BCoF activity or for ristocetin or botrocetin induced binding to platelets.
Reports on the topic "Centrifugation speed"
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Sagaiyaraj, Bernard. Increasing Energy Efficiency of Central Cooling Systems with Engineered Nanofluids. Department of the Built Environment, 2023. http://dx.doi.org/10.54337/aau538344493.
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Buildings consume about 40% of the world’s energy consumption and of that, 65% is dedicated to cooling (or heating) systems. Central building cooling uses water as the main heat transfer medium. The nanoparticle fluid suspension exhibits thermal properties superior to water. The goal was to achieve the highest possible thermal properties with just the right amount of nanoparticles in a uniform and stable dispersion and suspension in water. This engineered nanofluid contains a uniform and stable suspension of graphene nanoparticles (GNP) in water. Using covalent functionalization, centrifugation and high-speed dispersion, the GNP remains in a stable suspension indefinitely. The nanofluid is applied to the closed loop of the chilled water system, where the heat transfer enhancement occurs at the fluid tubes within the evaporator and the tubing in the chilled water coils within the Air Handling Units(AHUs). The Proof of Concept (POC) completed in 2019 using laboratory-derived nanofluid resulted in energy saving that averaged at 32% compared with the baseline fluid (water). In 2022, a Scaled-Up mini plant produced GNP nanofluids in a commercial process environment, showing an average energy savings of 21%. These results were further verified and validated on small chilled water plants outside of the Scaled-Up plant with 25% and 29% average savings.