Development and potential use of an Edwardsiella ictaluri wzz mutant as a live attenuated vaccine against enteric septicemia in Pangasius hypophthalmus (Tra catfish).

Edwardsiella ictaluri is a causative agent of enteric septicemia of catfish (ESC), a seriously lethal disease in Vietnamese catfish (Pangasius hypophthalmus). A safe and effective vaccine against ESC is currently an urgent demand due to antibiotic overuse in pangasius farms has led to an alarming antimicrobial resistance. In this study, two E.

Protein Motion and Configurations in a Form-Fitting Nanopore: Avidin in ClyA.

We probe the molecular dynamics and states of an avidin protein as it is captured and trapped in a voltage-biased cytolysin A nanopore using time-resolved single-molecule electrical conductance signals. The data for very large numbers of single-molecule events are analyzed and presented by a new method that provides clear visual insight into the molecular scale processes. Avidin in cytolysin A has surprisingly rich conductance spectra that reveal transient and more permanently trapped protein configurations in the pore and how they evolve into one another.

Field ionization of cold atoms near the wall of a single carbon nanotube.

We observe the capture and field ionization of individual atoms near the side wall of a single suspended nanotube. Extremely large cross sections for ionization from an atomic beam are observed at modest voltages due to the nanotube's small radius and extended length. The effects of the field strength on both the atomic capture and the ionization process are clearly distinguished in the data, as are prompt and delayed ionizations related to the locations at which they occur.

Creation of long-term coherent optical memory via controlled nonlinear interactions in Bose-Einstein condensates.

A Bose-Einstein condensate confined in an optical dipole trap is used to generate long-term coherent memory for light, and storage times of more than 1 s are observed. Phase coherence of the condensate as well as controlled manipulations of elastic and inelastic atomic scattering processes are utilized to increase the storage fidelity by several orders of magnitude over previous schemes. The results have important applications for creation of long-distance quantum networks and for generation of entangled states of light and matter.

Electro-optical nanotraps for neutral atoms.

We propose a new class of nanoscale electro-optical traps for neutral atoms. A prototype is the toroidal trap created by a suspended, charged carbon nanotube decorated with a silver nanosphere dimer. An illuminating laser field, blue detuned from an atomic resonance frequency, is strongly focused by plasmons induced in the dimer and generates both a repulsive potential barrier near the nanostructure surface and a large viscous damping force that facilitates trap loading.

Coherent control of optical information with matter wave dynamics.

In recent years, significant progress has been achieved in manipulating matter with light, and light with matter. Resonant laser fields interacting with cold, dense atom clouds provide a particularly rich system. Such light fields interact strongly with the internal electrons of the atoms, and couple directly to external atomic motion through recoil momenta imparted when photons are absorbed and emitted.

Detection and quantized conductance of neutral atoms near a charged carbon nanotube.

We describe a novel single atom detector that uses the high electric field surrounding a charged single-walled carbon nanotube to attract and subsequently field-ionize neutral atoms. A theoretical study of the field-ionization tunneling rates for atomic trajectories in the attractive potential near a nanowire shows that a broadly applicable, high spatial resolution, low-power, neutral-atom detector with nearly 100% efficiency is realizable with present-day technology. Calculations also show that the system can provide the first opportunity to study quantized conductance phenomena when detecting cold neutral atoms with mean velocities less than 15 m/s.

Observation of hybrid soliton vortex-ring structures in Bose-Einstein condensates.

We present the experimental discovery of compound structures comprising solitons and vortex rings in Bose-Einstein condensates. We examine both their creation via soliton-vortex collisions and their subsequent development, which is largely governed by the dynamics of interacting vortex rings. A theoretical model in three-dimensional cylindrical symmetry is also presented.

Enhancement of microcavity lifetimes using highly dispersive materials.

We show analytically and numerically that highly dispersive media can be used to drastically increase lifetimes of high- Q microresonators. In such a resonator, lifetime is limited either by undesired coupling to radiation, or by intrinsic absorption of the constituent materials. The presence of dispersion weakens coupling to the undesired radiation modes and also effectively reduces the material absorption.

Observation of quantum shock waves created with ultra- compressed slow light pulses in a Bose-Einstein condensate.

We have used an extension of our slow light technique to provide a method for inducing small density defects in a Bose-Einstein condensate. These sub- resolution, micrometer-sized defects evolve into large-amplitude sound waves. We present an experimental observation and theoretical investigation of the resulting breakdown of superfluidity, and we observe directly the decay of the narrow density defects into solitons, the onset of the "snake" instability, and the subsequent nucleation of vortices.

Observation of coherent optical information storage in an atomic medium using halted light pulses.

Electromagnetically induced transparency is a quantum interference effect that permits the propagation of light through an otherwise opaque atomic medium; a 'coupling' laser is used to create the interference necessary to allow the transmission of resonant pulses from a 'probe' laser. This technique has been used to slow and spatially compress light pulses by seven orders of magnitude, resulting in their complete localization and containment within an atomic cloud. Here we use electromagnetically induced transparency to bring laser pulses to a complete stop in a magnetically trapped, cold cloud of sodium atoms.