Morning Sickness: Symptoms of NAUSEA and VOMITING in pregnant women that usually occur in the morning during the first 2 to 3 months of PREGNANCY. Severe persistent vomiting during pregnancy is called HYPEREMESIS GRAVIDARUM.Meta-Analysis as Topic: A quantitative method of combining the results of independent studies (usually drawn from the published literature) and synthesizing summaries and conclusions which may be used to evaluate therapeutic effectiveness, plan new studies, etc., with application chiefly in the areas of research and medicine.Randomized Controlled Trials as Topic: Works about clinical trials that involve at least one test treatment and one control treatment, concurrent enrollment and follow-up of the test- and control-treated groups, and in which the treatments to be administered are selected by a random process, such as the use of a random-numbers table.Homoserine O-Succinyltransferase: The first enzyme in the METHIONINE biosynthetic pathway, this enzyme catalyzes the succinylation reaction of L-homoserine to O-succinyl-L-homoserine and COENZYME A using succinyl-CoA.Methylmethacrylates: The methyl esters of methacrylic acid that polymerize easily and are used as tissue cements, dental materials, and absorbent for biological substances.Methacrylates: Acrylic acids or acrylates which are substituted in the C-2 position with a methyl group.Boron Compounds: Inorganic or organic compounds that contain boron as an integral part of the molecule.Catechols: A group of 1,2-benzenediols that contain the general formula R-C6H5O2.Catechol 2,3-Dioxygenase: Catalyzes the oxidation of catechol to 2-hydroxymuconate semialdehyde in the carbazole and BENZOATE degradation via HYDROXYLATION pathways. It also catalyzes the conversion of 3-methylcatechol to cis, cis-2-hydroxy-6-oxohept-2,4-dienoate in the TOLUENE and XYLENE degradation pathway. This enzyme was formerly characterized as EC 22.214.171.124.Rhodopsin: A purplish-red, light-sensitive pigment found in RETINAL ROD CELLS of most vertebrates. It is a complex consisting of a molecule of ROD OPSIN and a molecule of 11-cis retinal (RETINALDEHYDE). Rhodopsin exhibits peak absorption wavelength at about 500 nm.Toluene: A widely used industrial solvent.Resin Cements: Dental cements composed either of polymethyl methacrylate or dimethacrylate, produced by mixing an acrylic monomer liquid with acrylic polymers and mineral fillers. The cement is insoluble in water and is thus resistant to fluids in the mouth, but is also irritating to the dental pulp. It is used chiefly as a luting agent for fabricated and temporary restorations. (Jablonski's Dictionary of Dentistry, 1992, p159)Acrylic ResinsXylenes: A family of isomeric, colorless aromatic hydrocarbon liquids, that contain the general formula C6H4(CH3)2. They are produced by the destructive distillation of coal or by the catalytic reforming of petroleum naphthenic fractions. (From McGraw-Hill Dictionary of Scientific and Technical Terms, 5th ed)Chlorobenzoates: Benzoic acid or benzoic acid esters substituted with one or more chlorine atoms.Congresses as Topic: Conferences, conventions or formal meetings usually attended by delegates representing a special field of interest.