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Biomedical subjects

J Lower

Publications and source records attributed to J Lower.

10 recordsLinked to original sources
PubMed2006

Electron-impact ionization and excitation of helium to the n=1-4 ionic states.

We present high-precision (e,2e) measurements and calculations for the e-He four-body Coulomb breakup problem. Cross-section ratios for ionization and excitation of the first three excited states of He+ relative to the ground state have been measured for incident energies between 112 and 319 eV. Comparing the data with predictions from a state-of-the-art hybrid distorted-wave+convergent R matrix with pseudostates (close coupling) approach shows that treating the projectile-target interaction at least to second order is crucial to obtain reasonable agreement between theory and experiment. Nevertheless, our benchmark studies reveal significant theoretical problems for the symmetric energy-sharing cases, thus indicating the need for further improvement.

Journal Article↗
PubMed2005

Triple coincidence (e,gamma2e) experiment for simultaneous electron impact ionization excitation of helium.

Simultaneous ionization and excitation of helium atoms by 500 eV electron impact is observed by a triple coincidence of an ionized slow electron, the recoiling He+ ion, and the radiated vacuum ultraviolet photon (lambda< or =30.4 nm). Kinematically complete differential cross sections are presented for the He+(2p)2P final ionic state, demonstrating the feasibility of a quantum mechanically complete experiment. The experimental data are compared to predictions from state-of-the-art numerical calculations. For large momentum transfers, a first-order treatment of the projectile-target interaction can reproduce the experimental angular dependence, but a second-order treatment is required to obtain consistent magnitudes.

Journal Article↗
PubMed2001

Magnetic and orbital dichroism in (e,2e) ionization of sodium.

We present the first measurement of (e,2e) ionization cross sections for a laser oriented atomic target by spin polarized electrons. Cross sections are presented as a function of target orientation and polarization direction of the incident electron beam. This study provides insight into mechanisms by which angular momentum is transferred from the valence electron to the two final-state continuum electrons in both singlet and triplet spin channels, by comparing measurement with distorted wave Born approximation and the dynamically screened three Coulomb wave calculations.

Journal Article↗
PubMed1986

Maxillofacial trauma.

Maxillofacial trauma runs the full gamut from minor discomfort to life-threatening injuries. Principles of airway management, adequate breathing, and circulation are paramount in the initial management. Health care professionals must anticipate problems based on a knowledge of anatomy and the pathophysiology of facial trauma and initiate treatment measures that decrease morbidity and mortality. Creative nursing approaches, based on a knowledge of physiologic needs and pathophysiologic consequences of facial trauma, are the keys in the convalescent phase as the patients struggle with alterated anatomy, sensory losses, and fear.

Airway Obstruction↗