Urea

Summary

Urea, also called carbamide (because it is a diamide of Carbamic acid), is an organic compound with chemical formula . This amide has two amino groups (–) joined by a carbonyl functional group (–C(=O)–). It is thus the simplest amide of carbamic acid. Urea serves an important role in the metabolism of nitrogen-containing compounds by animals and is the main nitrogen-containing substance in the urine of mammals. Urea is Neo-Latin, , , itself from Proto-Indo-European *h₂worsom. It is a colorless, odorless solid, highly soluble in water, and practically non-toxic ( is 15 g/kg for rats). Dissolved in water, it is neither acidic nor alkaline. The body uses it in many processes, most notably nitrogen excretion. The liver forms it by combining two ammonia molecules () with a carbon dioxide () molecule in the urea cycle. Urea is widely used in fertilizers as a source of nitrogen (N) and is an important raw material for the chemical industry. In 1828 Friedrich Wöhler discovered that urea can

Official source

https://en.wikipedia.org/wiki/Urea

About this result

This page is automatically generated and may contain information that is not correct, complete, up-to-date, or relevant to your search query. The same applies to every other page on this website. Please make sure to verify the information with EPFL's official sources.

Related publications (21)

Related publications

Related people (2)

Related people

Related units (1)

Related units

Related concepts (158)

Ammonia is an inorganic compound of nitrogen and hydrogen with the formula . A stable binary hydride, and the simplest pnictogen hydride, ammonia is a colourless gas with a distinct pungent smell. B

Nitrogen is the chemical element with the symbol N and atomic number 7. Nitrogen is a nonmetal and the lightest member of group 15 of the periodic table, often called the pnictogens. It is a common el

A fertilizer (American English) or fertiliser (British English) is any material of natural or synthetic origin that is applied to soil or to plant tissues to supply plant nutrients. Fertilizers may

Related concepts

Related courses (16)

The course is an introduction to heterogeneous catalysis for environmental protection and energy production. It focusses on catalytic exhaust gas cleaning as well as catalytic systems relevant for gaseous and liquid fuel production. The course ends with two days of experimental exercises at PSI.

This lecture presents the development of catalytic asymmetric reactions in organic chemistry, including important current topics of research in the field.

The course introduces the main classes of biomaterials used in the biomedical field. The interactions with biological environment are discussed and challenges highlighted. State of the art examples per type of material are discussed. Students will generate a biomaterial and study cell compatibility.

Related courses

Related lectures (25)

Related lectures

Performance and reproducibility of C-13 and N-15 hyperpolarization using a cryogen-free DNP polarizer

Arianna Ferrari, Hikari Ananda Infinity Yoshihara

The setup, operational procedures and performance of a cryogen-free device for producing hyperpolarized contrast agents using dissolution dynamic nuclear polarization (dDNP) in a preclinical imaging center is described. The polarization was optimized using the solid-state, DNP-enhanced NMR signal to calibrate the sample position, microwave and NMR frequency and power and flip angle. The polarization of a standard formulation to yield similar to 4 mL, 60 mM 1-C-13-pyruvic acid in an aqueous solution was quantified in five experiments to P(C-13) = (38 +/- 6) % (19 +/- 1) s after dissolution. The mono-exponential time constant of the build-up of the solid-state polarization was quantified to (1032 +/- 22) s. We achieved a duty cycle of 1.5 h that includes sample loading, monitoring the polarization build-up, dissolution and preparation for the next run. After injection of the contrast agent in vivo, pyruvate, pyruvate hydrate, lactate, and alanine were observed, by measuring metabolite maps. Based on this work sequence, hyperpolarized N-15 urea was obtained (P(N-15) = (5.6 +/- 0.8) % (30 +/- 3) s after dissolution).

NATURE PORTFOLIO2022

High-resolution cryo-EM structure of urease from the pathogen Yersinia enterocolitica

Henning Paul-Julius Stahlberg, Jasenko Zivanov

Urease converts urea into ammonia and carbon dioxide and makes urea available as a nitrogen source for all forms of life except animals. In human bacterial pathogens, ureases also aid in the invasion of acidic environments such as the stomach by raising the surrounding pH. Here, we report the structure of urease from the pathogen Yersinia enterocolitica at 2 Å resolution from cryo-electron microscopy. Y. enterocolitica urease is a dodecameric assembly of a trimer of three protein chains, ureA, ureB and ureC. The high data quality enables detailed visualization of the urease bimetal active site and of the impact of radiation damage. The obtained structure is of sufficient quality to support drug development efforts.

2020

Urea Derivative-Promoted CsPbl(2)Br Perovskite Solar Cells with High Open-Circuit Voltage

Xin Guo, Chen Li, Yang Liu, Bowen Yang

Inorganic perovskite solar cells (PSCs) have witnessed extraordinary advances owing to their prominent stability against thermal aging. However, they suffer from a phase transition from black phase to yellow phase under ambient conditions and serious energy losses relative to the optical bandgap. Herein, urea (Ur) and methyl-substituted urea (Me-Ur) additives are used to modulate the lattice structure and crystallinity of the CsPbI2Br, facilitating phase stability and high device performance. The Me-Ur can attenuate the strong hydrogen bonding networks in the Ur, which leads to stronger coordination of the carbonyl group with undercoordinated Pb2+, more efficiently passivating the defect states and suppressing the lattice distortion of the PbI6 octahedra in the CsPbI2Br perovskite. Consequently, a champion power conversion efficiency of 16.5% with an open-circuit voltage up to 1.33 V is obtained for the CsPbI2Br+Me-Ur-based PSCs, accompanied by enhanced stability under continuous illumination at a temperature of 45 +/- 5 degrees C. These results emphasize the importance of regulating the lattice distortion by the urea derivative to implement efficient and stable inorganic CsPbI2Br PSCs.

WILEY-V C H VERLAG GMBH2022