Development,validation, and implementation of capillary gel electrophoresis as a replacement for SDS‐PAGE for purity analysis of IgG2 mAbs

Capillary gel electrophoresis (CGE) methods with UV detection were developed for reduced and non‐reduced mAb analysis. These methods can be used to evaluate mAb purity, offering more reproducible quantitation compared with that of traditional SDS‐PAGE methods. These CGE methods have been utilized as platform technology for bioprocess development, formulation development, mAb characterization, drug substance/drug product release testing as well as a required methodology for stability testing. We have found these CGE methods to be applicable across a platform of mAbs in preclinical and clinical development, with the majority of mAbs requiring no modification to the method conditions. This methodology has been ICH validated and transferred to several supporting organizations. The data presented herein describes the development of CGE methodology, platform application to mAb purity analysis, ICH validation, reliability metrics, and considerations on technology enhancement for improved performance and throughput.     

Noise bandwidth dependence of soliton phase in simulations of stochastic nonlinear Schrödinger equations

We demonstrate that soliton perturbation theory, though widely used, predicts an incorrect phase distribution for solitons of stochastically driven nonlinear Schr?dinger equations in physically relevant parameter regimes. We propose a simple variational model that accounts for the effect of radiation on phase evolution and correctly predicts its distribution.     

Polyfluorinated cycloalkoxyphenyl ether systems as dopants for liquid crystal display applications

The effects on response times of representative commercially available dielectrically negative (−LC) and positive (+LC) type liquid crystal mixtures doped with small quantities of various tetrafluorinated cycloalkoxyphenyl ether derivatives were investigated. The synthesis of various polyfluoroaryl systems by nucleophilic aromatic substitution processes is described and electro-optical measurements concerning the rise and decay times and voltage holding ratios of each doped LC formulation are reported. The response time of the dielectrically negative LC host was improved upon doping with each of the tetrafluorinated cycloalkoxyphenyl ether derivatives, although no improvement in the performance of the dielectrically positive LC host was achieved.     

Shape resonances in slow electron scattering by aromatic molecules. I. Anthraquinone derivatives

A series of anthraquinone (C(14)O(2)H(8)) derivatives has been studied by means of electron capture negative ion mass spectrometry (ECNI-MS), photoelectron spectroscopy (PES), and AM1 quantum chemical calculations. Mean lifetimes of molecular negative ions M(-.) (MNI) have been measured. The mechanism of long-lived MNI formation in the epithermal energy region of incident electrons has been investigated. A simple model of a molecule (a spherical potential well with the repulsive centrifugal term) has been applied for the analysis of the energy dependence of cross sections at the first stage of the electron capture process. It has been shown that a temporary resonance of MNI at the energy approximately 0.5 eV corresponds to a shape resonance with lifetime 1-2.10(-13) s in the f-partial wave (l = 3) of the incident electron. The next resonant state of MNI at the energy approximately 1.7 eV has been associated with the electron excited Feshbach resonance (whose parent state is a triplet npi* transition). In all cases the initial electron state of the MNI relaxes into the ground state by means of a radiationless transition, and the final state of the MNI is a nuclear excited resonance with a lifetime measurable on the mass spectrometry timescale. Copyright 1999 John Wiley & Sons, Ltd.     

Description of chemical ordering in amorphous alloys

Partial coordination numbers $\text{Z}{}_{\mathrm{ij}}{}^1$ for a chemically disordered binary amorphous alloy A_XAB_XB are obtained in terms of total coordination numbers Z_i and average coordination numbers 〈Z〉 $\text{Z}{}_{\mathrm{ij}}{}^1\text{=x}{}_{\mathrm{j}}\text{Z}{}_{\mathrm{i}}\text{Z}{}_{\mathrm{j}}\text{/〈Z〉}$. Departures from complete chemical disorder are characterized by a short-range order coefficient with η_AB^max=x_BZ_B/x_AZ_A for X_BZ_B<x_AZ_A and η_AB^max=x_AZ_A/x_BZ_B for x_BZ_B>x_AZ_A.For complete chemical disorder ν_AB⁰ = 0; for complete chemical order, i.e. with chemical preference for AB nearest neighbor pairs, ν_AB⁰ = 1. For departures from chemical disorder associated with clustering, i.e. chemical preference against AB nearest neighbor pairs, ν_AB⁰ < 0. Experimental results for several amorphous alloys are used to demonstrate the usefulness of these results. A more precise calculation of η_AB^max is necessary to compare the degree of ordering in the metal-metalloid and metal-metal alloys.     

EXAFS studies of arsenic in amorphous silicon

Extended X-ray absorption fine structure measurements were used to determine nearest neighbor coordination numbers and distances for As in amorphous Si prepared by 100 keV As ion-implantation of single crystal Si. In the limit of low As concentration, the average As---Si coordination number was 3.2±0.1 and the As-to-Si distance was 2.37±0.02 Å, compared with 4 and 2.41±0.02 Å, respectively, for As in crystalline Si. It is concluded that 20% of the As atoms are fourfold coordinated and 80% are threefold coordinated in the amorphous Si, and that the lack of electrical doping by the fourfold coordinated As results from electron trapping by dangling bonds or other structural defects.