Abstract: In a weft thread brake mechanism with a controllable braking effect, a controllable braking force is applied to a weft thread as it passes between two lamellar braking members, such as leaf spring members. A servomotor, preferably a stepper motor, rotatingly drives an eccentric brake effect control member that cooperates with at least one of the lamellar brake members. Through the eccentric rotation of the braking effect control member, it presses to a varying degree against at least one of the lamellar braking members. Thus, a varying braking force is applied by the lamellar braking members to the weft thread. A programmable computer control provides control signals for the stepper motor.

Abstract: A mixture of fluorescently-excitable amino acid derivatives suitable for use in quantitative amino acid analysis is provided in which primary amino acids are present as derivatives of a first reagent and secondary amino acids are present as derivatives of a second different reagent. The process for preparing the mixture comprises the steps of derivatization of the primary amino acids of an amino acid sample with ortho-phthalaldehyde (OPA) and of derivatization of the secondary amino acids of the sample with fluorenylmethylchloroformate (FMOC) in the presence of acetonitrile. The mixture can be obtained automatically and is highly suitable for fast analysis by reversed-phase liquid chromatography.