WordNet

ride or float on an inflated tube; "We tubed down the river on a hot summer day"
conduit consisting of a long hollow object (usually cylindrical) used to hold and conduct objects or liquids or gases (同)tubing
electronic device consisting of a system of electrodes arranged in an evacuated glass or metal envelope (同)vacuum_tube, thermionic vacuum tube, thermionic_tube, electron_tube, thermionic_valve
(anatomy) any hollow cylindrical body structure (同)tube-shaped structure
convey in a tube; "inside Paris, they used to tube mail"
place or enclose in a tube
provide with a tube or insert a tube into
the amount that a tub will hold; "a tub of water" (同)tubful
a large open vessel for holding or storing liquids (同)vat
of a tire; having an inner tube

PrepTutorEJDIC

(金属・ガラス・ゴムなどの)管,筒 / (絵の具・歯みがきなどの)チューブ / 《米》(列車・地下鉄の)トンネル / 《英》地下鉄(《米》subway) / (ラジオ・テレビなどの)真空管(vacuum tube) / (動植物の)管状器官
『おけ』,たらい / 《話》'bath 2 / (また tubful)おけ1杯[の量](の…)《+of+名》 / 《話》のろくてぶかっこうな船;《俗》でぶ,太っちょ
〈U〉管状の物 / 《集合的に》管類 / 〈C〉(ある長さの1本の)管

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出典(authority):フリー百科事典『ウィキペディア（Wikipedia）』「2015/05/28 06:01:06」(JST)

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A laboratory centrifuge is a piece of laboratory equipment, driven by a motor, which spins liquid samples at high speed. There are various types of centrifuges, depending on the size and the sample capacity.^[1]

Like all other centrifuges, laboratory centrifuges work by the sedimentation principle, where the centripetal acceleration is used to separate substances of greater and lesser density.

Types

Laboratory centrifuge

There are various types of centrifugation:

Differential centrifugation, often used to separate certain organelles from whole cells for further analysis of specific parts of cells
Isopycnic centrifugation, often used to isolate nucleic acids such as DNA
Sucrose gradient centrifugation, often used to purify enveloped viruses and ribosomes, and also to separate cell organelles from crude cellular extracts

There are different types of laboratory centrifuges:

Microcentrifuges

(devices for small tubes from 0.2 ml to 2.0 ml (micro tubes), up to 96 well-plates, compact design, small footprint; up to 30,000 g)

Clinical centrifuges

(moderate-speed devices used for clinical applications like blood collection tubes)

Multipurpose high-speed centrifuges

(devices for a broad range of tube sizes, high variability, big footprint)

Ultracentrifuges

(analytical and preparative models)

Because of the heat generated by air friction (even in ultracentrifuges, where the rotor operates in a good vacuum), and the frequent necessity of maintaining samples at a given temperature, many types of laboratory centrifuges are refrigerated and temperature regulated.

There are different providers of laboratory centrifuges like Eppendorf, Thermoline Scientific, Thermo-Heraeus, Thermo-Sorvall, Hettich, Beckmann-Coulter, MSE, Sigma and AWEL International.

Centrifuge tubes

Centrifuge tubes are precision-made, high-strength tubes of glass or plastic made to fit exactly in rotor cavities. They may vary in capacity from 50 mL down to much smaller capacities used in microcentrifuges used extensively in molecular biology laboratories. Microcentrifuges typically accommodate disposable plastic microcentrifuge tubes with capacities from 250 μL to 2.0 mL.

Glass centrifuge tubes can be used with most solvents, but tend to be more expensive. They can be cleaned like other laboratory glassware, and can be sterilized by autoclaving. They must be handled with care, since small scratches can cause failure under the strong forces imposed during a run. Glass tubes are inserted into soft rubber sleeves to cushion them during runs. Plastic centrifuge tubes, especially tend to be less expensive and, with care, can be just as durable as glass. Water is preferred when plastic centrifuge tubes are used. They are more difficult to clean thoroughly, and are usually inexpensive enough to be considered disposable.

Disposable plastic "Eppendorf tubes" of 0.5ml to 2ml are commonly used in microcentrifuges. They are molded from a flexible transparent plastic similar to polythene, are semi-conical in shape, with integral, hinged sealing caps.

Larger samples are spun using centrifuge bottles, which range in capacity from 250 to 1000 millilitres. Although some are made of heavy glass, centrifuge bottles are usually made of shatter-proof plastics such as polypropylene or polycarbonate. Sealing closures may be used for added leak-proof assurance.

Safety

An Eppendorf laboratory centrifuge

The load in a laboratory centrifuge must be carefully balanced. This is achieved by using a combination of samples and balance tubes which all have the same weight or by using various balancing patterns without balance tubes.^[2] Small differences in mass of the load can result in a large force imbalance when the rotor is at high speed. This force imbalance strains the spindle and may result in damage to the centrifuge or personal injury. Some centrifuges have an automatic rotor imbalance detection feature that immediately discontinues the run when an imbalance is detected.

Before starting a centrifuge, an accurate check of the rotor and lid locking mechanisms is mandatory. Centrifuge rotors should never be touched while moving, because a spinning rotor can cause serious injury. Modern centrifuges generally have features that prevent accidental contact with a moving rotor as the main lid is locked during the run.

Centrifuge rotors have tremendous kinetic energy during high speed rotation. Rotor failure, caused by mechanical stress from the high forces imparted by the motor, can occur due to manufacturing defects, routine wear and tear, or improper use and maintenance. Such a failure can be catastrophic failure, especially with larger centrifuges, and generally results in total destruction of the centrifuge. While centrifuges generally have safety shielding to contain these failures, such shielding may be inadequate, especially in older models, or the entire centrifuge unit may be propelled from its position, resulting in damage to nearby personnel and equipment. Uncontained rotor failures have shattered laboratory windows and destroyed refrigerators and cabinetry. To reduce the risk of rotor failures, centrifuge manufactures specify operating and maintenance procedures to ensure that rotors are regularly inspected and removed from service or derated (only operated at lower speeds) when they are past their expected lifetime.^[3]

Another potential hazard is the aerosolization of hazardous samples during centrifugation. To prevent contamination of the laboratory, rotor lids with special aerosol-tight gaskets are available. The rotor can be loaded with the samples within a hood and the rotor lid fixed on the rotor. Afterwards, the aerosol-tight system of rotor and lid is transferred to the centrifuge. The rotor can then be fixed within the centrifuge without opening the lid. After the run, the entire rotor assembly, including the lid, is removed from the centrifuge to the hood for further steps, maintaining the samples within a closed system.

A ThermoFisher laboratory bench-top centrifuge.

References

^ Susan R. Mikkelsen & Eduardo Cortón. Bioanalytical Chemistry, Ch. 13. Centrifugation Methods. John Wiley & Sons, Mar 4, 2004, pp. 247-267.
^ Frothingham, R (February 1999). "Centrifugation without a balance tube". American Laboratory (Shelton, CT: International Scientific Communications) 31 (19): 10. ISSN 0044-7749. Retrieved March 18, 2011.
^ Cornell University EH&S. "Centrifuge Accident". Retrieved 29 December 2010.

External links

RCF Calculator and Nomograph
Centrifugation Rotor Calculator
Selection of historical centrifuges in the Virtual Laboratory of the Max Planck Institute for the History of Science

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English Journal

Bactericidal effect of hydroxyl radicals generated from a low concentration hydrogen peroxide with ultrasound in endodontic treatment.

Kobayashi Y1, Hayashi M1, Yoshino F2, Tamura M3, Yoshida A2, Ibi H1, Lee MC4, Ochiai K3, Ogiso B1.
Journal of clinical biochemistry and nutrition.J Clin Biochem Nutr.2014 May;54(3):161-5. doi: 10.3164/jcbn.13-86. Epub 2014 Apr 9.
One approach to enhance the disinfection of root canals in endodontic treatment is ultrasonic irrigation with sodium hypochlorite. Reactive oxygen species, such as hydroxyl radical, are generated by biological defense systems to kill invading bacteria. Ultrasonic irrigation with hydrogen peroxide ma
PMID 24895478

Establishment of a new immunological method for direct detection of Mycobacterium in solution.

Hamzehlou S1, Farajollahi MM2.
Journal of microbiology, immunology, and infection = Wei mian yu gan ran za zhi.J Microbiol Immunol Infect.2014 Apr 21. pii: S1684-1182(14)00037-1. doi: 10.1016/j.jmii.2014.02.007. [Epub ahead of print]
BACKGROUND/PURPOSE: Tuberculosis (TB) is a crucial health problem. Prevention of the disease requires rapid diagnosis. Rapid liquid culture systems, nucleic acid amplification tests, and high-performance liquid chromatography (HPLC) are among the rapid tests used for detecting Mycobacterium species.
PMID 24767420

Passive ultrasonic irrigation in the presence of a low concentration of hydrogen peroxide enhances hydroxyl radical generation and bactericidal effect against Enterococcus faecalis.

Kobayashi Y1, Hayashi M, Yoshino F, Tamura M, Yoshida A, Ibi H, Lee MC, Ochiai K, Ogiso B.
Journal of oral science.J Oral Sci.2014;56(1):35-9.
Chemomechanical procedures can be used to eliminate bacteria from root canals. However, detectable bacteria sometimes remain because of the complexity of the root canal system. Endodontic passive ultrasonic irrigation (PUI) with hydrogen peroxide (H2O2) may be a promising option for increasing bacte
PMID 24739706

Japanese Journal

Bactericidal effect of hydroxyl radicals generated from a low concentration hydrogen peroxide with ultrasound in endodontic treatment

Kobayashi Yoshimi,Hayashi Makoto,Yoshino Fumihiko,Tamura Muneaki,Yoshida Ayaka,Ibi Haruna,Lee Masaichi-Chang-il,Ochiai Kuniyasu,Ogiso Bunnai
Journal of Clinical Biochemistry and Nutrition 54(3), 161-165, 2014
… An ultrasonic tip was submerged in 0.5 or 1.0 M hydrogen peroxide in a microfuge tube. … hydrogen peroxide was irradiated with the ultrasound, the tip of which was maintained centered in the tube to mimic ultrasonic irrigation. …
NAID 130004466753

Passive ultrasonic irrigation in the presence of a low concentration of hydrogen peroxide enhances hydroxyl radical generation and bactericidal effect against Enterococcus faecalis

Kobayashi Yoshimi,Hayashi Makoto,Yoshino Fumihiko,Tamura Muneaki,Yoshida Ayaka,Ibi Haruna,Lee Masaichi-Chang-il,Ochiai Kuniyasu,Ogiso Bunnai
Journal of Oral Science 56(1), 35-39, 2014
… An ultrasonic tip was submerged in 0.45 mol/L (1.5%) H2O2 in a microfuge tube. … H2O2 was activated by an ultrasonic unit, the tip of which was kept centered in the tube, to mimic PUI. …
NAID 130003393076

A Simple Method for Cell Isolation from Paraffin-Embedded Tissue Spscimens for Flow Cyrometric DNA Analysis.

Oga Atsunori,Ohzono Yuko,Yoshizawa Hiroto,Sasaki Kohsuke
The bulletin of the Yamaguchi Medical School 46(3-4), 99-104, 1999-12
… All cell isolation procedures were done in a 1.5-ml microfuge tube without centrifugation. …
NAID 120000865856