玻尿酸前驅物 相關
廣告關鍵就在:米蘭時尚診所玻尿酸微整隆鼻,改善臉部輪廓. 就要給你好臉色!玻尿酸+皮秒2合1,快速填補淚溝、蘋果肌,找回紅潤氣色#電洽
搜尋結果
In condensed matter physics, a Bose–Einstein condensate ( BEC) is a state of matter that is typically formed when a gas of bosons at very low densities is cooled to temperatures very close to absolute zero (−273.15 °C or −459.67 °F).
CRISPR (/ ˈ k r ɪ s p ər /) (an acronym for clustered regularly interspaced short palindromic repeats) is a family of DNA sequences found in the genomes of prokaryotic organisms such as bacteria and archaea. These sequences are derived from DNA fragments of bacteriophages that had previously infected the prokaryote. ...
- CRISPR
- Escherichia coli
Sulfuric acid ( American spelling and the preferred IUPAC name) or sulphuric acid ( Commonwealth spelling ), known in antiquity as oil of vitriol, is a mineral acid composed of the elements sulfur, oxygen, and hydrogen, with the molecular formula H2SO4. It is a colorless, odorless, and viscous liquid that is miscible with water. [6]
- Uses
- Side Effects
- Synthesis
- Nomenclature
- Coordination Chemistry Principles
- Environmental Concerns
- Alternatives to EDTA
- Methods of Detection and Analysis
- In Popular Culture
- External Links
Textiles and paper
In industry, EDTA is mainly used to sequester (bind or confine) metal ions in aqueous solution. In the textile industry, it prevents metal ion impurities from modifying colours of dyed products. In the pulp and paper industry, EDTA inhibits the ability of metal ions, especially Mn2+, from catalysing the disproportionation of hydrogen peroxide, which is used in chlorine-free bleaching.
Food
In a similar manner, EDTA is added to some food as a preservativeor stabiliser to prevent catalytic oxidative decolouration, which is catalysed by metal ions.
Water softener
The reduction of water hardness in laundry applications and the dissolution of scale in boilers both rely on EDTA and related complexants to bind Ca2+, Mg2+, as well as other metal ions. Once bound to EDTA, these metal complexes are less likely to form precipitates or to interfere with the action of the soaps and detergents.[citation needed] For similar reasons, cleaning solutions often contain EDTA. In a similar manner EDTA is used in the cement industry for the determination of free lime an...
EDTA exhibits low acute toxicity with LD50 (rat) of 2.0 g/kg to 2.2 g/kg. It has been found to be both cytotoxic and weakly genotoxic in laboratory animals. Oral exposures have been noted to cause reproductive and developmental effects. The same study also found that both dermal exposure to EDTA in most cosmetic formulations and inhalation exposure...
The compound was first described in 1935 by Ferdinand Münz, who prepared the compound from ethylenediamine and chloroacetic acid. Today, EDTA is mainly synthesised from ethylenediamine (1,2-diaminoethane), formaldehyde, and sodium cyanide.This route yields the tetrasodium EDTA, which is converted in a subsequent step into the acid forms: 1. H2NCH2C...
To describe EDTA and its various protonated forms, chemists distinguish between EDTA4−, the conjugate base that is the ligand, and H4EDTA, the precursor to that ligand. At very low pH (very acidic conditions) the fully protonated H6EDTA2+ form predominates, whereas at very high pH or very basic condition, the fully deprotonated EDTA4− form is preva...
In coordination chemistry, EDTA4− is a member of the aminopolycarboxylic acid family of ligands. EDTA4− usually binds to a metal cation through its two amines and four carboxylates, i.e., it is a hexadentate ("six-toothed") chelating agent. Many of the resulting coordination compounds adopt octahedral geometry. Although of little consequence for it...
Abiotic degradation
EDTA is in such widespread use that questions have been raised whether it is a persistent organic pollutant. While EDTA serves many positive functions in different industrial, pharmaceutical and other avenues, the longevity of EDTA can pose serious issues in the environment. The degradation of EDTA is slow. It mainly occurs abioticallyin the presence of sunlight. The most important process for the elimination of EDTA from surface waters is direct photolysis at wavelengths below 400 nm. Depend...
Biodegradation
In many industrial wastewater treatment plants, EDTA elimination can be achieved at about 80% using microorganisms. Resulting byproducts are ED3A and iminodiacetic acid(IDA) – suggesting that both the backbone and acetyl groups were attacked. Some microorganisms have even been discovered to form nitrates out of EDTA, but they function optimally at moderately alkaline conditions of pH 9.0–9.5. Several bacterial strains isolated from sewage treatment plants efficiently degrade EDTA. Specific st...
Interest in environmental safety has raised concerns about biodegradability of aminopolycarboxylates such as EDTA. These concerns incentivize the investigation of alternative aminopolycarboxylates. Candidate chelating agents include nitrilotriacetic acid (NTA), iminodisuccinic acid (IDS), polyaspartic acid, S,S-ethylenediamine-N,N′-disuccinic acid ...
The most sensitive method of detecting and measuring EDTA in biological samples is selected reaction monitoring capillary electrophoresis mass spectrometry (SRM-CE/MS), which has a detection limit of 7.3 ng/mL in human plasma and a quantitation limit of 15 ng/mL.This method works with sample volumes as small as 7–8 nL. EDTA has also been measured i...
In the movie Blade(1998), EDTA is used as a weapon to kill vampires, exploding when in contact with vampire blood.
Oviedo, Claudia; Rodríguez, Jaime (2003). "EDTA: The chelating agent under environmental scrutiny". Química Nova. 26 (6): 901–905. doi:10.1590/S0100-40422003000600020.Hydrogen peroxide is a chemical compound with the formula H 2 O 2. In its pure form, it is a very pale blue [5] liquid that is slightly more viscous than water. It is used as an oxidizer, bleaching agent, and antiseptic, usually as a dilute solution (3%–6% by weight) in water for consumer use, and in higher concentrations for industrial use.
Amphetamine [note 2] (contracted from a lpha - m ethyl ph en et hyl amine) is a central nervous system (CNS) stimulant that is used in the treatment of attention deficit hyperactivity disorder (ADHD), narcolepsy, and obesity. Amphetamine was discovered as a chemical in 1887 by Lazăr Edeleanu, and then as a drug in the late 1920s. [26] .
A representation of the 3D structure of the protein myoglobin showing turquoise α-helices. This protein was the first to have its structure solved by X-ray crystallography. Toward the right-center among the coils, a prosthetic group called a heme group (shown in gray) with a bound oxygen molecule (red). Proteins are large biomolecules and ...