Urea

Manufactured by Merck Group

Sourced in United States, Germany, United Kingdom, Italy, India, France, Sao Tome and Principe, China, Australia, Spain, Poland, Belgium, Switzerland, Canada, Mexico, Macao, Pakistan, Croatia, Finland, Czechia, Chile, Sweden

Urea is a chemical compound with the formula CO(NH2)2. It is a colorless, odorless, and crystalline solid that is highly soluble in water. Urea's core function is to serve as a source of nitrogen and a key component in many biochemical processes.

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Lab products found in correlation

Dithiothreitol (dtt), by Merck Group (177 mentions) Iodoacetamide, by Merck Group (148 mentions) Sodium chloride (nacl), by Merck Group (119 mentions) Thiourea, by Merck Group (107 mentions) Formic acid, by Merck Group (94 mentions) Sodium hydroxide (naoh), by Merck Group (92 mentions) Hydrochloric acid (hcl), by Merck Group (80 mentions) Ammonium bicarbonate, by Merck Group (79 mentions) Methanol, by Merck Group (67 mentions) Ethanol, by Merck Group (66 mentions) Trifluoroacetic acid, by Merck Group (57 mentions) Bovine serum albumin (bsa), by Merck Group (55 mentions) Sodium dodecyl sulfate (sds), by Merck Group (54 mentions) Citric acid, by Merck Group (53 mentions) Acetonitrile, by Merck Group (53 mentions) Trypsin, by Promega (53 mentions) Glycerol, by Merck Group (51 mentions) Triton x 100, by Merck Group (51 mentions) Potassium chloride (kcl), by Merck Group (50 mentions) Uric acid, by Merck Group (45 mentions)

1 227 protocols using urea

Urea Sensing Device Characterization

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urease from Jack Beans (Type III, powder, 20,000 units/g), urea (molecular biology grade, powder), phosphate-buffered saline (PBS, pH 7.4), (3-amino-propyl) triethoxysilane (APTES, 99%), glutaraldehyde (50%), glucose, ascorbic acid (AA), KCl, and anhydrous ethanol (200 proof, 99.5%) were purchased from Sigma-Aldrich (Burlington, VT, USA).
Prior to the experiments, a urea solution was prepared by dissolving urea powder in a 1 × PBS solution of pH 6. To test the selectivity of the device, other biomolecules such as glucose, AA, and KCl were also dissolved in the 1 × PBS solution with a pH of 6. The electrical characteristics of the device were measured using a semiconductor parameter analyzer (Keithley 4200, Keithley, Solon, OH, USA). The gate voltage (V_G) was applied in increments of 50 mV through a buffer solution, while the drain current (I_D) was measured with a fixed drain voltage (V_D) of 0.1 V. The source and body voltages (V_S and V_B) were set to 0 V. I_D was limited to 10⁻⁷ A to prevent the degradation of the device. The I_D−V_G characterizations were performed after exposing the target solution of 20 μL for 10 min.

Choi W., Jin B., Shin S., Do J., Son J., Kim K, & Lee J.S. (2023). Highly Sensitive Detection of Urea Using Si Electrolyte-Gated Transistor with Low Power Consumption. Biosensors, 13(5), 565.

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Fabrication of Paclitaxel-Loaded Nylon-12 Coatings

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Experimental DCBs for PTX delivery were prepared using previously described techniques. Briefly, coatings containing PTX (LC Laboratories, MA) and urea (Sigma-Aldrich) (w/w 1:1) were prepared via controlled micropipetting of the drug-excipient solution onto flat Nylon-12 surfaces.^{23 (link)} The coating solution was formed with the agitated (~200 rpm) dissolution of PTX and urea (15 mg/mL of each constituent) in ethanol (200 proof) for 4 h. Nylon-12 films (0.5 mm thickness) were cut into squares (25 × 25 mm²), sonicated in an ethanol bath at 40 °C to remove any potential surface particles, uniformly coated with urea-PTX solution (120 μL), and stored at room temperature and controlled humidity (<5%) for 6 h. This process resulted in coated samples with 3 μg/mm² of each constituent. In an identical fashion, urea-only and PTX-only coatings were prepared (coating density of 3 μg/mm² for each) for comparative analyses. All samples were stored in a desiccator at room temperature until use to prevent rehydration.

Azar D., Lott J.T., Jabbarzadeh E., Shazly T, & Kolachalama V.B. (2020). Surface Modification Using Ultraviolet-Ozone Treatment Enhances Acute Drug Transfer in Drug-Coated Balloon Therapy. Langmuir : the ACS journal of surfaces and colloids, 36(17), 4645-4653.

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Hydrogel Swelling Response to Urea

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After synthesis and washing of the gels with and without the functionalized enzyme Urease, the hydrogel mass m₀ was determined using a balance (Entris 224-1S, Sartorius, Goettingen, Germany) and the pH value of the solution was measured using a pH meter (FiveEasy Plus, Mettler-Toledo, Gießen, Germany). Urea (Sigma Aldrich) was dissolved in PBS buffer and each gel was incubated in 3 mL of the Urea solution for 24 h. After the determination of the hydrogel mass m and the pH value of the surrounding solution, the solution was changed to the next higher Urea concentration. This procedure was repeated several times. In total, the hydrogel sensitivity with regard to Urea was tested in a range from 1 mmol/L up to 100 mmol/L Urea. Based on the measured hydrogel masses, the swelling degree S was calculated according to Equation (1):

Erfkamp J., Guenther M, & Gerlach G. (2019). Enzyme-Functionalized Piezoresistive Hydrogel Biosensors for the Detection of Urea. Sensors (Basel, Switzerland), 19(13), 2858.

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Urea effects on viable and non-viable E. Coli

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Urea (Sigma-Aldrich, St. Louis, MO) was diluted with PBS in to two concentrations; 285 mM, corresponding to the urine Urea level in humans and 1800 mM, corresponding to the urine Urea level in mice (Yang and Bankir, 2005 (link)). Fifty μL of 100% viable or 100% non-viable bacteria, corresponding to 1-2x10⁷ colony-forming units (CFU) of E. Coli was added to 50 μL of the Urea solutions. The DNA of the PMA treated and untreated samples was extracted and amplified as described above.

Lee A.S., Lamanna O.K., Ishida K., Hill E., Nguyen A, & Hsieh M.H. (2022). A Novel Propidium Monoazide-Based PCR Assay Can Measure Viable Uropathogenic E. coli In Vitro and In Vivo. Frontiers in Cellular and Infection Microbiology, 12, 794323.

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Microwave-Assisted Synthesis of Carbon Dots

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Urea and citric acid (Merck, Darmstadt, Germany) were used as the precursors for the synthesis of CDs by a microwave. First, 3 g Urea and 10.5 g citric acid were added to a 50 mL volumetric flask, and then, 18.2 MΩ cm (Milli-Q, Millipore) ultrapure water was added to the volume. After a homogeneous mixture of Urea and citric acid, the solution was transferred to Teflon tubes, which were put in a microwave system (CEM, Mars 6). The synthesis condition of the microwave was set at 800 watts, heated at 200 °C for 15 minutes. After the reaction of the microwave, the Teflon tubes were kept in machine for 30 min for cooling down, and then, the solution was filtered through a 0.22 μm pore size filter. Subsequently, the CDs solution was dialyzed with a dialysis membrane (3500 dalton MW) for 4 h, and all the processes should be performed away from light. Finally, the dialysis CDs solution was stored in the 4 °C refrigerator before use.

Kung J.C., Tseng I.T., Chien C.S., Lin S.H., Wang C.C, & Shih C.J. (2020). Microwave assisted synthesis of negative-charge carbon dots with potential antibacterial activity against multi-drug resistant bacteria. RSC Advances, 10(67), 41202-41208.

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Urea-Formaldehyde Fragrance Microencapsulation

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Example 3

2 grams of Urea (Sigma Aldrich of Milwaukee, Wis.) is dissolved in 20 g deionized water. 1 gram of resorcinol (Sigma Aldrich of Milwaukee, Wis.) is added to the homogeneous Urea solution. 20 g of 37 wt % formaldehyde solution (Sigma Aldrich of Milwaukee, Wis.) is added to the solution, and the pH of the slurry is adjusted to 8.0 using 1M sodium hydroxide solution (Sigma Aldrich of Milwaukee, Wis.). The reactants are allowed to sit at 35° C. for 2 hours. In a separate beaker, 80 grams of fragrance oil is added slowly to the Urea-formaldehyde solution. The mixture is agitated using a Janke & Kunkel Laboretechnik mixer using a pitched, 3-blade agitator to achieve a 12 micron mean oil droplet size distribution, with a standard deviation of 2 microns. The pH of the slurry is adjusted to 3.0 using 1M Hydrochloric Acid to initiate the condensation reaction. The solution is heated to 65° C. and allowed to react in a constant temperature water bath, while slowly agitating the contents of the mixture. The contents are allowed to react for 4 hours at 65° C.

US10154949B2. Personal care compositions and methods (2018-12-18). The Procter & Gamble Company [US]. Inventors: Jonathan Robert Cetti [US], Jiten Odhavji Dihora [US], Steven Edward Witt [US], Eric Shane Henley [US].

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Synthesis of hBN-Urea Composite

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The hBN powder (Sigma Aldrich, St. Louis, MO, USA) and urea (98%, Daejung Chemicals, Siheung, Gyeonggi, Korea) were mixed in a steel container at a weight ratio of 1:100 (hBN 50 mg, urea 5 g), and the mixture was milled with a rotational speed of 700 rpm for 20 h in Ar atmosphere using a planetary ball mill (Pulverisette 7, Fritsch, Idar-Oberstein, RP, Germany). To remove excess urea and disperse it in water at a concentration of 1 mg/ml, a mixed powder of urea and hBN flakes was dissolved in 50 ml of deionized water and dialyzed for 1 week using a dialysis kit (Sigma Aldrich, St. Louis, MO, USA).

Jang W., Han S., Gu T., Chae H, & Whang D. (2021). hBN Flake Embedded Al2O3 Thin Film for Flexible Moisture Barrier. Materials, 14(23), 7373.

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Synthesis of Double-walled Ge-INTs

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Double-walled Ge-INTs were
synthesized using aluminum perchlorate nonahydrate (reagent grade,
Alfa Aesar), tetraethoxygermane (TEOG, ≥99.95%, Sigma-Aldrich),
and urea (>99%, Sigma-Aldrich) following the procedure described
elsewhere.^{32 (link)} TEOG was mixed in a PTFE beaker
with an aqueous
solution of aluminum perchlorate (C = 0.2 mol L^–1) and a urea solution with a molar ratio of [Ge]:[Al]:[urea]
= 1:2:2. After mixing, the PTFE beaker was placed in an acid digestion
bomb (Zeoclave, Maximator, France) for hydrothermal treatment at 140
°C. The solution was recovered after 5 days and then dialyzed
against ultrapure water using semipermeable membranes (Spectra/Por,
cutoff = 10 kDa) until the conductivity of the bath drops below 0.5
mS m^–1.^{37 (link)}

Moore J.F., Paineau E., Launois P, & Shaffer M.S. (2021). Continuous Binder-Free Fibers of Pure Imogolite Nanotubes. ACS Applied Materials & Interfaces, 13(15), 17940-17947.

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Recombinant p24 Protein Purification

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Recombinant p24 proteins were purified from E. coli as previously described (59 (link)) with minor modification. For the expression and purification of the fusion protein, E. coli BL21 strains (RBC Bioscience, Taipei City, Taiwan) were transformed with pET23a-p24. Protein expression was induced by adding 0.4 mM isopropyl β-d-thiogalactoside (Duchefa Biochemie, Haarlem, Netherlands). Bacterial cells were harvested and disrupted by sonication on ice for 10 min. Sonicated lysates were centrifuged at 1,600 × g for 20 min at 4°C, and the pellets containing p24 protein were resuspended in binding buffer containing 4 M urea (Sigma Aldrich, St. Louis, MO, USA). The proteins were purified using Ni-NTA His binding resin (Merck, Darmstadt, Germany) and eluted with elution buffer (300 mM NaCl, 50 mM sodium phosphate buffer, 250 mM imidazole) containing 4 M urea. Purified proteins were dialyzed serially against the elution buffer to remove imidazole, urea, and residual salts. Purity of p24 protein was estimated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE; 12% gel). The gel was visualized using Coomassie brilliant blue staining methods (60 (link)) (Figure S9 in Supplementary Material).

Kim B.J., Kim B.R., Kook Y.H, & Kim B.J. (2018). Development of a Live Recombinant BCG Expressing Human Immunodeficiency Virus Type 1 (HIV-1) Gag Using a pMyong2 Vector System: Potential Use As a Novel HIV-1 Vaccine. Frontiers in Immunology, 9, 643.

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Quantifying α-Synuclein Fibril Disassembly

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Fibril stock preparations (4 to 5 mg/ml in TBS) were diluted to a final concentration of 0.1 mg/ml in TBS. For each guanidine hydrochloride (guanidinium, GdnHCl; Sigma-Aldrich), urea (Sigma-Aldrich), and PK (Sigma-Aldrich) concentration, 10 μl (1 μg) of PFF was mixed 1:1 with 10 μl of stock solutions to make 0, 0.5, 1, 1.5, 2, 2.5, 3, and 3.5 M GdnHCl final concentrations; 0, 0.5, 1, 2, 3, 4, 5, and 6 M urea final concentrations; and 0, 0.5, 1, 1.5, 2, 2.5, 3, and 3.5 μg/ml PK final concentrations. Mixtures were gently vortexed before incubation for 1 hour at room temperature for GdnHCl, 6 hours at room temperature for urea, and 30 min at 37°C for PK. At the end of the incubation period, treatments were stopped by quickly diluting the samples with 500 μl of PBS and directly subjecting them (100 μl per immunoblotting antibody) to filter-trap assay as previously described. The different α-syn species were quantified by immunolabeling with conformation-specific, monomeric, or pan α-syn antibodies (table S1) and expressed as a percentage of related untreated samples, allowing to draw curves of PFF disassembly, denaturation, and proteolysis with GdnHCl, urea, and PK, respectively.

De Giorgi F., Laferrière F., Zinghirino F., Faggiani E., Lends A., Bertoni M., Yu X., Grélard A., Morvan E., Habenstein B., Dutheil N., Doudnikoff E., Daniel J., Claverol S., Qin C., Loquet A., Bezard E, & Ichas F. (2020). Novel self-replicating α-synuclein polymorphs that escape ThT monitoring can spontaneously emerge and acutely spread in neurons. Science Advances, 6(40), eabc4364.

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