The Fc effector functions of immunoglobulin G (IgG) antibodies are in part determined by structural features of carbohydrates linked to each of the paired gamma heavy chains in the antibody constant domain (C(H)2). One glycoform that has been shown to be advantageous is G2, where both arms of complex bi-antennary N-glycans terminate in galactose. In vitro treatment with glycosyltransferases can remodel heterogeneous IgG glycoforms, enabling preparation of IgG molecules with homogeneous glycan chains. Here we describe optimization of conditions for use of a soluble recombinant galactosyltransferase in vitro to remodel glycans of human serum IgG, and we demonstrate a scaled-up reaction in which >98% of neutral glycans attached to 1 kg IgG are converted to the G2 glycoform. Removal of glycosylation reagents from the product is achieved in one step by affinity chromatography on immobilized Protein A.

No abstract

Sweep Frequency Response Analysis (SFRA) is a powerful technique to detect mechanical damage in transformer windings, such as deformations and displacements, as well as other failures, helping to prevent severe damage. Since SFRA is a sensitive diagnostic technique, there are nowadays several commercially available measurement instruments to perform the tests, but the failure interpretation is usually based on expert opinion. One of the most advisable ways to face the task of interpretation of SFRA test results is the use of mathematical indexes to detect abnormalities along with an interpretation scheme. The failure interpretation methodology of SFRA tests must establish the possible relationships between frequency ranges and specific failures, because different failure types can be detected in different frequency ranges of the SFRA trace. This article proposes a new methodology for power transformer failure diagnosis using the relationships between the different decomposition levels of the original trace obtained by the use of the Discrete Wavelet Transform and the definition of frequency regions with variable limits, according the shape of the trace. Moreover, an interpretation map and a vector fitting analysis are also proposed in order to establish a specific failure.

No abstract