Enrichment of adeno-associated virus serotype 5 full capsids by anion exchange chromatography with dual salt elution gradients.

Adeno-associated virus-based gene therapies have demonstrated substantial therapeutic benefit for the treatment of genetic disorders. In manufacturing processes, viral capsids are produced with and without the encapsidated gene of interest. Capsids devoid of the gene of interest, or "empty" capsids, represent a product-related impurity.

Observation of small cluster formation in concentrated monoclonal antibody solutions and its implications to solution viscosity.

Monoclonal antibodies (mAbs) are a major class of biopharmaceuticals. It is hypothesized that some concentrated mAb solutions exhibit formation of a solution phase consisting of reversibly self-associated aggregates (or reversible clusters), which is speculated to be responsible for their distinct solution properties. Here, we report direct observation of reversible clusters in concentrated solutions of mAbs using neutron spin echo.

Small-angle neutron scattering characterization of monoclonal antibody conformations and interactions at high concentrations.

Small-angle neutron scattering (SANS) is used to probe the solution structure of two protein therapeutics (monoclonal antibodies 1 and 2 (MAb1 and MAb2)) and their protein-protein interaction (PPI) at high concentrations. These MAbs differ by small sequence alterations in the complementarity-determining region but show very large differences in solution viscosity. The analyses of SANS patterns as a function of different solution conditions suggest that the average intramolecular structure of both MAbs in solution is not significantly altered over the studied protein concentrations and experimental conditions.

Shear-induced metastable states of end-grafted polystyrene.

The in situ molecular scale response of end-grafted polystyrene to shear against a deuterated polystyrene melt was investigated with neutron reflectometry. The derived grafted polystyrene density profiles showed that the grafted polystyrene was retained on the quartz wafer during the measurements. The profiles suggested that the end-grafted polystyrene response to shear results in a series of metastable states, rather than equilibrium states assumed in the current theory.

The Los Alamos Neutron Science Center neutron rheometer in the cone and plate geometry to examine tethered polymers/polymer melt interfaces via neutron reflectivity.

Although several other neutron rheometers have been built to study soft matter under nonequilibrium conditions, none of them have the ability to measure the structure and behavior of the polymeric interfacial regions in highly viscous polymer melts which require high torques/high strain rates and high temperatures. A neutron rheometer in the cone and plate geometry has been constructed at the Los Alamos Neutron Science Center to rectify this lack of experimental instrumentation. It is also the first-of-its-kind to perform neutron reflectivity studies concurrently with rheological measurements.

The Couette configuration of the Los Alamos Neutron Science Center neutron rheometer for the investigation of polymers in the bulk via small-angle neutron scattering.

A neutron rheometer in the Couette geometry has been built at the Los Alamos Neutron Science Center to examine the molecular steady-state and dynamic responses of entangled polymeric materials in the bulk under the application of shear stress via small-angle neutron scattering. Although similar neutron rheometers have been fabricated elsewhere, this new design operates under the extreme conditions required for measuring the structure and behavior of high molecular weight polymer melts. Specifically, the rheometer achieves high torques (200 N m) and shear rates (865 s(-1)) simultaneously, never before attainable with other neutron rheometers at temperatures up to 240 degrees C under an inert gas environment.

5-Aminonaphthalene-1-sulfonic acid and its manganese, nickel and cobalt salts.

5-Ammonionaphthalene-1-sulfonate monohydrate, C10H9NO3S x H2O, contains layers of zwitterionic molecules with the acidic sulfonic acid H atom transferred to the amine N atom. Within each layer, the charged groups (NH3(+) and SO3(-)) are directed to the surface of the layer and are inverted on adjacent molecules. The naphthalene rings in a given layer are all parallel.

Binding of genistein to the estrogen receptor based on an experimental electron density study.

In a continuing effort to determine a relationship between the biological function and the electronic properties of steroidal and nonsteroidal estrogens by analysis of the submolecular properties, an experimental charge density study has been pursued on the nonsteroidal phytoestrogen, genistein. X-ray diffraction data were obtained using a Rigaku R-Axis Rapid high-power rotating anode diffractometer with a curved image plate detector at 20(1) K. The total electron density was modeled using the Hansen-Coppens multipole model.

2,3,10,11-Tetrathiatricyclo[10.4.0.0(4,9)]hexadeca-4,6,8,12,14,16-hexaene (precession camera versus CCD).

The title compound, C(12)H(8)S(4), has crystallographic \overline{1} symmetry, the benzene groups thus being anti with respect to the plane of the four S atoms. The S-S and C-S bond lengths of the sulfur-carbon eight-membered ring were found to be similar to those in other structures containing such sulfur-carbon rings. There is evidence for pi-pi interactions between the aromatic rings of neighboring molecules, linking them into sheets.