Spin amplification, reading, and writing in transport through anisotropic magnetic molecules

Inelastic transport through a single magnetic molecule weakly coupled to metallic leads is studied theoretically. We consider dynamical processes that are relevant for writing, storing, and reading spin information in molecular memory devices. Magnetic anisotropy is found to be crucial for slow spin relaxation. In the presence of anisotropy we find giant spin amplification: The spin accumulated in the leads if a bias voltage is applied to a molecule prepared in a spin-polarized state can be made exponentially large in a characteristic energy divided by temperature. For one ferromagnetic and one paramagnetic lead the molecular spin can be reversed by applying a bias voltage even in the absence of a magnetic field. We propose schemes for reading and writing spin information based on our findings.Comment: 5+ pages with 5 figure

Off-Shell Electromagnetic Form Fators of the Nucleon in Chiral Perturbation Theory

We study the electromagnetic form factors of a nucleon in next-to-leading order chiral perturbation theory (CPT) in the case where one of the nucleons is off its mass shell. We calculate the leading nonanalytic contributions to relevant measures for the off-shell dependence in the limited kinematical range allowed.Comment: 3 pages LaTeX with worldsci.sty (available by mailing [email protected] and typing "get worldsci.sty" in the subject line), invited talk given at the International Symposium on Medium Energy Physics, Beijing, August 199

An open source LABVIEW platform for simulating image series of fluorescent microtubules in gliding assays

We describe an open-source LabVIEW software platform for generating simulated images of microtubules in gliding motility assays. We describe how the software works and how to obtain the software

Remotely operated gripper provides vertical control rod movement

Remote actuation of a gripper shaft affects vertical engagement between a drive shaft and control rod. A secondary function of the gripper is to provide remote indication of positive completion of the gripping or ungripping operation

Dynamic Moment Analysis of the Extracellular Electric Field of a Biologically Realistic Spiking Neuron

Based upon the membrane currents generated by an action potential in a biologically realistic model of a pyramidal, hippocampal cell within rat CA1, we perform a moment expansion of the extracellular field potential. We decompose the potential into both inverse and classical moments and show that this method is a rapid and efficient way to calculate the extracellular field both near and far from the cell body. The action potential gives rise to a large quadrupole moment that contributes to the extracellular field up to distances of almost 1 cm. This method will serve as a starting point in connecting the microscopic generation of electric fields at the level of neurons to macroscopic observables such as the local field potential

Computer aided processing using laser measurements

The challenge exists of processing the STS and its cargo through KSC facilities in the most timely and cost effective manner possible. To do this a 3-D computer graphics data base was established into which was entered the STS, payloads, and KSC facilities. The facility drawing data are enhanced by laser theodolite measurements into an as-built configuration. Elements of the data base were combined to study orbiter/facility interfaces payload/facility access problems and design/arrangement of various GSE to support processing requirements. With timely analysis/design utilizing the 3-D computer graphics system, costly delays can be avoided. Better methodology can be analyzed to determine procedures for cost avoidance

Recall of Group Tasks as a Function of Group Cohesiveness and Interruption of Tasks

The paper demonstrates that the motivational concepts underlying the Zeigarnik effect pertaining to individuals attempting to achieve their personal goals can be applied to individuals who are working to attain the group goals. However, this is true only for individuals in cohesive groups as opposed to noncohesive groups

Effect of 2-H and 18-O water isotopes in kinesin-1 gliding assay

We show here the effects of heavy-hydrogen water (^2^H~2~O) and heavy-oxygen water (H~2~^18^O) on the gliding speed of microtubules on kinesin-1 coated surfaces. Increased fractions of isotopic waters used in the motility solution decreased the gliding speed of microtubules by a maximum of 21% for heavy-hydrogen and 5% for heavy-oxygen water. We discuss possible interpretations of these results and the importance for future studies of water effects on kinesin and microtubules. We also discuss the implication for biomolecular devices incorporating molecular motors

Versatile Control System for Automated Single-Molecule Optical Tweezers Investigations

We present a versatile control system to automate single-molecule biophysics experiments. This method combines low-level controls into various functional, user-configurable modules, which can be scripted in a domain-specific instruction language. The ease with which the high-level parameters can be changed accelerates the development of a durable experiment for the perishable single-molecule samples. Once the experimental parameters are tuned, the control system can be used to repeatedly manipulate other single molecules in the same way, which is necessary to accumulate the statistics needed to report results from single-molecule studies. This system has been implemented for an optical tweezers instrument for single-molecule manipulations, with real-time point-by-point feedback at a loop rate of 10-20 kHz