- Methyl cellulose
chembox verifiedrevid 476994062 ImageFile Methyl cellulose.png ImageSize 200px IUPACName OtherNames Cellulose, methyl ether methylated cellulose methylcellulose E461 Section1 Chembox Identifiers CASNo Ref cascite correct CAS CASNo 9004 67 5 PubChem ChemSpiderID Ref chemspidercite correct chemspider ChemSpiderID NA SMILES ATCCode prefix A06 ATCCode suffix AC06 Section2 Chembox Properties Formula variable MolarMass variable Appearance Density MeltingPt BoilingPt Solubility Section3 Chembox Hazards MainHazards FlashPt Autoignition Methyl cellulose or methylcellulose is a chemical compound derived from cellulose . It is a hydrophile hydrophilic white powder in pure form and dissolves in cold but not in hot water, forming a clear viscous solution or gel. It is sold under a variety of trade names and is used as a thickener and emulsifier in various food and cosmetic products, and also as a treatment of constipation . Like cellulose, it is not digestible, not toxic, and not an allergen . Chemistry Methyl cellulose does not occur naturally and is synthetically produced by heating cellulose with caustic solution e.g. a solution of sodium hydroxide and treating it with methyl chloride . In the substitution reaction that follows, the hydroxyl residues OH functional groups are replaced by methoxide OCH sub 3 sub groups . Different kinds of methyl cellulose can be prepared depending on the number of hydroxyl groups substituted. Cellulose is a polymer consisting of numerous linked glucose molecules, each of which exposes three hydroxyl groups. The Degree of Substitution DS of a given form of methyl cellulose is defined as the average number of substituted hydroxyl groups per glucose. The theoretical maximum is thus a DS of 3.0, however more typical values are 1.3 2.6. Different methyl cellulose preparations can also differ in the average length of their polymer backbones. Solubility and temperature Methyl cellulose has a lower critical solution temperature LCST between 40 C and 5 ... more details
|
- Fascin
structure with pseudo 2 fold symmetry. It is stabilized by a hydrophobe hydrophobic core and a hydrophile ... more details
|
- PEGylation
Image Polyethylene glycol.png thumb Polyethylene glycol PEGylation is the process of covalent attachment of polyethylene glycol polymer chains to another molecule, normally a drug or therapeutic protein. PEGylation is routinely achieved by incubation of a reactive derivative of PEG with the target macromolecule. The covalent attachment of PEG to a drug or therapeutic protein can mask the agent from the host s immune system reduced immunogenicity and antigenicity , and increase the hydrodynamic size size in solution of the agent which prolongs its circulatory time by reducing renal clearance. PEGylation can also provide water solubility to hydrophobic drugs and proteins. History Around 1970, Dr. Frank F. Davis, a professor of biochemistry at Rutgers University, became interested in developing a process to render usable bioactive proteins of potential medical value. After considerable study, he concluded that the attachment of an inert and Hydrophile hydrophilic polymer might extend blood life and control immunogenicity of the proteins . ref Davis, F. F. 2002 The origin of pegnology , Advanced Drug Delivery Reviews 54 4 457 458, http dx.doi.org 10.1016 S0169 409X 02 00021 2 ref Polyethylene glycol PEG was chosen as the polymer. A team of Dr. Davis, Dr. Theodorus Van Es and Dr. Nicholas C. Palczuk conducted animal studies and found that PEG attachment greatly extended blood life and controlled immunogenicity of the proteins. A patent was obtained. ref Davis, F. F., Van Es, T., and Palczuk, N. C. 1979 United States Patent 4,179,337. Originally filed in 1973 . http patft.uspto.gov netacgi nph Parser?Sect1 PTO1&Sect2 HITOFF&d PALL&p 1&u 2Fnetahtml 2FPTO 2Fsrchnum.htm&r 1&f G&l 50&s1 4179337.PN.&OS PN 4179337&RS PN 4179337 ref Dr. Abraham Abuchowski conducted extensive additional PEGylation studies on various enzymes. ref Abuchowski, A. McCoy, J. R. Palczuk, N. C. van Es, T. Davis, F. F. 1977 , Effect of covalent attachment of polyethylene glycol on immunogenicity and circ ... more details
|
- Scoring functions for docking
hydrophobe hydrophobic hydrophobic contacts favorable , hydrophobic hydrophile hydrophilic contacts ... more details
|
- In vitro compartmentalization
emulsion formation, a mixture of Hydrophilic lipophilic balance HLB hydrophile lipophile balance ... more details
|
- Finishing (textiles)
by polymer deposition on coating as a fine film. Hydrophile Hydrophilic finishes compensate for lower ... more details
|
- Graphite oxide
1 and 5 10 sup 3 sup S cm at a Biasing bias voltage of 10 V. ref name gomez However, being Hydrophile ... more details
|
- Glycine
. It can fit into Hydrophile hydrophilic or Hydrophobe hydrophobic environments, due to its two hydrogen ... more details
|
- Fluorescence recovery after photobleaching
Image Frap diagram.svg right thumb 320px Principle of FRAP A The bilayer is uniformly labeled with a fluorescent tag B This label is selectively photobleached by a small 30 micrometre fast light pulse C The intensity within this bleached area is monitored as the bleached dye diffuses out and new dye diffuses in D Eventually uniform intensity is restored Fluorescence recovery after photobleaching FRAP denotes an optical technique capable of quantifying the two dimensional lateral diffusion of a molecularly thin film containing fluorescently labeled probes, or to examine single cells. This technique is very useful in biological studies of cell membrane diffusion and protein binding. In addition, surface deposition of a fluorescing phospholipid bilayer or monolayer allows the characterization of hydrophile hydrophilic or hydrophobe hydrophobic surfaces in terms of surface structure and free energy. Similar, though less well known, techniques have been developed to investigate the 3 dimensional diffusion and binding molecular binding of molecules inside the cell they are also referred to as FRAP. Experimental Setup The basic apparatus comprises an optical microscope , a List of light sources light source and some fluorescent probe. Fluorescence Fluorescent emission is contingent upon absorption of a specific optical wavelength or color which restricts the choice of lamps. Most commonly, a broad spectrum mercury element mercury or xenon source is used in conjunction with a color filter. The technique begins by saving a background image of the sample before photobleaching. Next, the light source is focused onto a small patch of the viewable area either by switching to a higher magnification microscope objective or with laser light of the appropriate wavelength. The fluorophores in this region receive high intensity illumination which causes their fluorescence lifetime to quickly elapse limited to roughly 10 sup 5 sup photons before extinction . Now the image in the micros ... more details
|
- Xenobiotic metabolism
the extracellular mixture. This selective uptake means that most hydrophile hydrophilic molecules ... more details
|
- Tremors (TV series)
near where the cloud is, deduces that it is a Hydrophile hydrophilic bacteria that was a project ... more details
|
- Lacritin
appears to be amphipathic with hydrophobe hydrophobic and hydrophile hydrophilic residues on opposite ... more details
|
- Potential applications of carbon nanotubes
for example, gallium nitride nanotubes are hydrophile hydrophilic , while CNTs are hydrophobe hydrophobic ... more details
|
- Parts cleaning
Parts cleaning is essential to many List of industrial processes industrial processes , as a prelude to surface finishing or to protect sensitive components. Electroplating is particularly sensitive to part cleanliness, since molecular layers of oil can prevent adhesion of the coating . ASTM B322 is a standard guide for cleaning metal s prior to electroplating. Cleaning processes include solvent cleaning, hot alkali ne detergent cleaning, electrocleaning, and Industrial etching acid etch . The most common industrial test for cleanliness is the waterbreak test, in which the surface is thoroughly rinsed and held vertical. Hydrophobe Hydrophobic contaminants such as oils cause the water to bead and break up, allowing the water to drain rapidly. Perfectly clean metal surfaces are Hydrophile hydrophilic and will retain an unbroken sheet of water that does not bead up or drain off. ASTM F22 describes a version of this test. This test does not detect hydrophilic contaminants, but the electroplating process can displace these easily since the solutions are water based. Surfactant s such as soap reduce the sensitivity of the test, so these must be thoroughly rinsed off. Definitions and classifications For the activities described here the following terms are often found metal cleaning, metal surface cleaning, component cleaning, degreasing, parts washing, parts cleaning. These are well established in technical language usage but they have their shortcomings. Metal cleaning can easily be mixed up with refinement of unpurified metals. Metal surface cleaning and metal cleaning do not consider the increasing usage of plastic s and composite material s in this sector. The term component cleaning leaves out the cleaning of steel sections and sheets and finally degreasing only describes a part of the topic as in most cases also chips, fines, particles, salts etc. have to be removed. The terms commercial and industrial parts cleaning , parts cleaning in craft and industry or commerc ... more details
|
- Statin development
polar methane Sulfonamide chemistry sulfonamide group, which is quite Hydrophile hydrophilic and confers ... more details
|
- Janus particles
of Oil Droplets in Water journal J. Am. Chem. Soc. year 2005 ref In 2009, hydrophile hydrophilic ... more details
|
- Organic chemistry
tend to be somewhat hydrophile hydrophilic , usually form esters , and usually can be converted ... more details
|
- Blood?brain barrier
File 10.1371 journal.pbio.0050169.g001 O.jpg 250px right thumb Part of a network of capillary capillaries supplying brain cell s File Blood Brain Barriere.jpg thumb right The astrocytes type 1 surrounding capillaries in the brain The blood brain barrier BBB is a separation of circulating blood from the brain extracellular fluid BECF in the central nervous system CNS . It occurs along all capillaries and consists of tight junctions around the capillaries that do not exist in normal circulation. Endothelial cell s restrict the diffusion of microscopic objects e.g. bacteria and large or Hydrophile hydrophilic molecules into the cerebrospinal fluid CSF , while allowing the diffusion of small Hydrophobe hydrophobic molecules O sub 2 sub , CO sub 2 sub , hormones . Cells of the barrier actively transport metabolism metabolic products such as glucose across the barrier with specific proteins. This barrier also includes a thick basement membrane and Astrocyte astrocytic endfeet. History Paul Ehrlich was a bacteriology bacteriologist studying staining , a procedure that is used in many microscopic studies to make fine biological structures visible using chemical dyes. When Ehrlich injected some of these dyes notably the aniline dye s that were then widely used , the dye would stain all of the organ anatomy organs of some kinds of animals except for their brain s. At that time, Ehrlich attributed this lack of staining to the brain s simply not picking up as much of the dye citation needed date February 2012 . However, in a later experiment in 1913, Edwin Goldmann one of Ehrlich s students injected the dye into the cerebro spinal fluid s of animals brains directly. He found that in this case the brains did become dyed, but the rest of the body did not. This clearly demonstrated the existence of some sort of compartmentalization between the two. At that time, it was thought that the blood vessel s themselves were responsible for the barrier, since no obvious membrane could be f ... more details
|
- Poly(methyl methacrylate)
hydroxyl hydroxyl group s make them hydrophile hydrophilic . In orthopedic surgery , PMMA bone cement ... more details
|
- LSm
between Hydrophile hydrophilic amino acid side chains around the periphery of the contact area. RNA ... more details
|
- Temperature-responsive polymer
transition will occur sooner. Under LCST, the hydrophile hydrophilic surfaces of polymer chains interact ... more details
|
- Carbon nanotubes in photovoltaics
phenyl C sub 61 sub butyric acid methyl ester PCBM Al solar cell. By dip coating from a Hydrophile hydrophilic ... more details
|
- Discovery and development of integrase inhibitors
ions in a rather Hydrophile hydrophilic region, anchoring the inhibitor onto the protein surface ... more details
|
- Amino acid
base , and a hydrophile if the side chain is polar molecule polar or a hydrophobe if it is nonpolar ... more details
|
- Material properties of diamond
carbon atoms terminate with a hydrogen atom and Hydrophile hydrophilic when the surface atoms ... more details
|
Encyclopedia
top
