Time-of-flight spin-echo small-angle neutron scattering applied to biological cell nuclei

The organization of chromatin in the nuclei of rat lymphocyte was studied by time-of-flight spin-echo small-angle neutron scattering (ToF-SESANS). The procedures of the measurements in ToF and monochromatic SESANS modes were compared. It is shown that the sensitivity of the ToF method is significantly higher than that of the monochromatic mode....

The microscopic distribution of hydrophilic polymers in interpenetrating polymer networks (IPNs) of medical grade silicone

By introducing hydrophilic polymers into silicone medical devices, highly beneficial biomedical properties can be realized. An established solution to introduce hydrophilic polymers is to form an interpenetrating polymer network (IPN) by performing the hydrogel synthesis in the presence of silicone swollen in supercritical carbon dioxide. The...

Mesoporous Silica Formation Mechanisms Probed Using Combined Spin-Echo Modulated Small-Angle Neutron Scattering (SEMSANS) and Small-Angle Neutron Scattering (SANS)

The initial formation stages of surfactant-templated silica thin films which grow at the air-water interface were studied using combined spin-echo modulated small-angle neutron scattering (SEMSANS) and small-angle neutron scattering (SANS). The films are formed from either a cationic surfactant or nonionic surfactant (C16EO8) in a dilute...

Evolution of dispersion in the melt compounding of a model polymer nanocomposite system: A multi-scale study

We investigate the morphological development of polystyrene (PS)-C ₆₀ nanocomposites along the length of a prototype co-rotating twin-screw extruder with sampling capabilities. The effects of C ₆₀ concentration and output on the morphological evolution along the extruder are studied employing a suite of characterization...

Small-angle neutron scattering (SANS) and spinecho SANS measurements reveal the logarithmic fractal structure of the large-scale chromatin organization in HeLa nuclei

This paper reports on the two-scale fractal structure of chromatin organization in the nucleus of the HeLa cell. Two neutron scattering methods, small-angle neutron scattering (SANS) and spin-echo SANS, are used to unambiguously identify the large-scale structure as being a logarithmic fractal with the correlation function (r) - ln(r/E). The...

Spin-echo small-angle neutron scattering study of the structure organization of the chromatin in biological cell

Spin-echo small-angle scattering (SESANS) technique is a method to measure the structure of materials from nano- to micrmeter length scales. This method could be important for studying the packaging of DNA in the eukaryotic cell. We measured the SESANS function from chicken erythrocyte nuclei which is well fitted by the exponential function G...

High-strength bacterial cellulose-polyacrylamide hydrogels: Mesostructure anisotropy as studied by spin-echo small-angle neutron scattering and cryo-SEM

Submicron- and micron-scale structures of composite hydrogels based on bacterial cellulose (BC) and polyacrylamide (PAAm) were studied by spin-echo small-angle neutron scattering (SESANS) and cryo-scanning electron microscopy (cryo-SEM). These hydrogels possessing the structure of interpenetrating polymer network were synthesized via free...

Additive scaling law for structural organization of chromatin in chicken erythrocyte nuclei

Small-angle neutron scattering (SANS) on nuclei of chicken erythrocytes demonstrates the cubic dependence of the scattering intensity Q−3 in the range of momentum transfer Q∈10−3–10−2nm−1. Independent spin-echo SANS measurements give the spin-echo function, which is well described by the exponential law in a range of sizes (3×102)–(3×104) nm....

Polarization optimization of spin-echo small angle scattering instruments

The polarization optimization in a small angle scattering spin-echo setup is considered, under the depolarization and phase errors that occur in field transition regions by improper adjustment of inclined magnetized foils as n-flippers. Various correction procedures are discussed. In these setups with precession fields perpendicular to the beam...