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Do biological motors move with regular steps? To address this question, we constructed instrumentation with the spatial and temporal sensitivity to resolve movement on a molecular scale. We deposited silica beads carrying single molecules of the motor protein kinesin on microtubules using optical tweezers and analysed their motion under controlled loads by(More)
The force produced by a single molecule of Escherichia coli RNA polymerase during transcription was measured optically. Polymerase immobilized on a surface was used to transcribe a DNA template attached to a polystyrene bead 0.5 micrometer in diameter. The bead position was measured by interferometry while a force opposing translocation of the polymerase(More)
We studied fluctuations in the displacement of silica beads driven by single molecules of the motor protein kinesin, moving under low mechanical loads at saturating ATP concentrations. The variance in position was significantly smaller than expected for the case of stepwise movement along a regular lattice of positions with exponentially distributed(More)
Biomolecular membranes display rich statistical mechanical behavior. They are classified as liquid in the absence of shear elasticity in the plane of the membrane and tethered (solid) when the neighboring molecules or subunits are connected and the membranes exhibit solid-like elastic behavior in the plane of the membrane. The spectrin skeleton of red blood(More)
BACKGROUND Central neurocytoma (CN) represents a rare, relatively recently described primary central nervous system tumor. It ranks among intraventricular tumors due to its predominant location within the lateral brain ventricles. CN occurs mostly in young adults around the 3rd decade of life; almost a fifth of the cases are children under 18 years of age.(More)
OBJECTIVE To compare the reliability and validity of two classification systems used to evaluate the quality of mammograms: PGMI ('perfect', 'good', 'moderate' and 'inadequate') and EAR ('excellent', 'acceptable' and 'repeat'). SETTING New South Wales (Australia) population-based mammography screening programme (BreastScreen NSW). METHODS Thirty sets of(More)
(81)—poorly understood. Although complex, a mechanistic, cellular-level explanation of S1 map plasticity appears increasingly tractable and would constitute a major step toward understanding cortical information storage. Language acquisition is one of the most fundamental human traits, and it is obviously the brain that undergoes the developmental changes.(More)
(81)—poorly understood. Although complex, a mechanistic, cellular-level explanation of S1 map plasticity appears increasingly tractable and would constitute a major step toward understanding cortical information storage. Language acquisition is one of the most fundamental human traits, and it is obviously the brain that undergoes the developmental changes.(More)