Chromatographic behavior of a polyclonal antibody mixture on a strong cation exchanger column. Part II: Adsorption modelling

The adsorption of a polyclonal IgG mixture on a strong cation exchanger column is characterized using a detailed multi-component pore model. This model is explicit in all transport parameters and includes salt dependent isotherms. As discussed in the first part of this work, the IgG mixture can be simplified by considering two pseudo-variants only. Linear gradient experiments are used to fit the salt dependent adsorption isotherms and the mass transport parameters for the two pseudo-variants. Using the model, breakthrough curves are predicted with good accuracy. The model is also implemented to visualize the axial and radial concentration profiles of the two pseudo-variants in the column during a loading experiment.     

Preparative weak cation-exchange chromatography of monoclonal antibody variants I. Single-component adsorption

The retention behavior of a monoclonal antibody has been characterized on a weak cation exchanger, Fractogel EMD COO(-)(s). This new generation of resin materials comprise of a higher mechanical strength compared to softer gel-type matrices while maintaining elevated capacities, resulting in higher productivity and longer lifetimes. These parameters are extremely important when working with large bio-molecules such as proteins, and in particular monoclonal antibodies. In the first part of this work a parameter estimation strategy is presented to fully characterize the retention behavior of a single monoclonal antibody and determine suitable model parameters. Literature correlations were used for the estimation of mass transfer rates. The transport limiting parameter, pore diffusion, was regressed experimentally. Various methods for the adsorption isotherm determination have been applied, their combinations resulting in little experimental effort and accurate predictions of elution profiles. The process has been modelled with a complete pore diffusion model and the agreement between experimental and predicted profiles is good in general. However, a very marked sensitivity to changes in the effective pore diffusion coefficient has been observed. A correlation describing the effect of the separation conditions on the diffusion rate is therefore needed in order to have a fully predictive mathematical model.     

Morphosynthesis of strontianite nanowires using polyacrylate templates tethered onto self-assembled monolayers

Strontianite nanowires have been synthesized on self-assembled monolayers (SAM) in the presence of polyacrylate templates. The morphology of this product exhibits characteristic differences from that of products obtained in the absence of polyacrylate. It is demonstrated that the template-induced crystallization process involves the interaction between the SAM surface, polyacrylate (a dissolved polyelectrolyte), and the cations/anions in solution. By the combination of these components, hierarchically ordered mineral hybrid structures are formed.     

Evidence for Bs* Bs* production at the Gamma(5S) resonance

We use data collected by the CLEO III detector at the Cornell Electron Storage Ring to measure the inclusive yields of D(s) mesons as B(Y(5S) --> D(s)X) = (44-7 +/- 4.2 +/- 9.9)% and B(Y(4S) --> D(s)X) = (18.1 +/- 0.5 +/- 2.8)%. From these measurements, we make a model dependent estimate of the ratio of B(s)*B(s)* to the total bb quark pair production of (16.0 +/- 2.6 +/- 5.8)% at the Y(5S) energy.     

Search for X(3872) in gammagamma fusion and radiative production at CLEO

We report on a search for the recently reported X(3872) state using 15.1 fb(-1) of e(+)e(-) data taken in the sqrt[s] = 9.46-11.30 GeV region. Separate searches for the production of the X(3872) in untagged gammagamma fusion and e(+)e(-) annihilation following initial state radiation are made by taking advantage of the unique angular correlation between the leptons from the decay J/psi --> l(+)l(-) in X(3872) decay to pi(+)pi(-)J/psi. No signals are observed in either case, and 90% confidence upper limits are established as (2J+1)Gamma(gammagamma)(X(3872))B(X --> pi(+)pi(-)J/psi) < 12.9 eV and Gamma(ee)(X(3872))B(X- -> pi(+)pi(-)J/psi) < 8.3 eV.     

Production potential of medical isotopes from natural uranium fission processes

Journal of Radioanalytical and Nuclear Chemistry - We present the results of gamma ray yield measurements from the neutron induced fission of natural uranium at a low power research reactor. Our...     

Study of oxidation of alloy 1.4306S (SS-304L) in air and steam at 1200°C using the Mössbauer technique

The Mössbauer technique has been used to study the oxidation of alloy 1.4306S (SS-304L) at 1200°C exposed in atmospheres of air and steam, for, 1, 6, 24, 100 and 400 hours. By oxidation in air the major products are -FE₂O₃, -FE₂O₃, and Fe₃O₄ while, during oxidation in steam they are -FeOOH, -Fe₂O₃ and Fe₃O₄. A minor phase detected following both kinds of oxidation may be ascribed to MnCrFeO₄, Cr₂FeO₄, -FeOOH and -FeOOH produced in steam only while the base material is found following air oxidation. The proportion of Fe₃O₄ on the scale remains constant for all exposure durations in air oxidation, while it becomes constant in steam oxidation only in cases where the entire sample has been oxidized.