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L Reimer

Publications and source records attributed to L Reimer.

25 records · Page 2Linked to original sources
PubMed1975

Superposition of chromatic error and beam broadening in transmission electron microscopy of thick carbon and organic specimens.

The chromatic error is calculated using our scattering cross sections obtained from contrast experiments and a distribution function of energy losses from Misell and Burge. The assumed ratio of total inelastic and elastic cross sections was 3.5. Monte-Carlo calculations were performed for the multiple scattering problem of thick carbon specimens using these values for single scattering. As expected, a minimum confusion of the chromatic error disc exists at underfocusing. The half width broadening of an edge is in good agreement with experiments at 100 keV if the experimental method of determining the half width is also taken into consideration theoretically. The lateral displacements of electron paths normal to the direction of the electron incidence, which give rise to poorer resolution at the bottom of a thick specimen in scanning transmission electron microscopy, cannot simply be added to the chromatic error in the normal mode of transmission electron microscopy. Calculations show that there is no difference in edge resolution at 100 keV to be expected, in agreement with experiment. With increasing energy, the influence of beam broadening increases relative to the chromatic error. Considering only the chromatic error (1-2 nm), at 1 MeV and optimum defocus details on the top of a 2 micron specimen will be imaged with nearly twice the value of edge half width as they will at the bottom.

Carbon↗
PubMedDate not supplied

Infectious diarrhea: pathogens and treatment.

Infectious diarrhea is the most common infectious disease syndrome worldwide resulting in more than five million deaths annually. The greatest morbidity and mortality is seen among children younger than two years of age. A variety of bacterial, viral and parasitic pathogens are responsible for the various syndromes. A combination of host susceptibility and organism virulence factors is responsible for disease. Most episodes of gastroenteritis are self-limited. The hallmark of patient management is strict attention to fluid and electrolyte disturbances. Antimotility agents should be used with caution if at all in children, but may be helpful in adults with travelers' diarrhea. Antimicrobial therapy may shorten the duration of diarrhea in some illnesses, but use is restricted due to emergence of resistance or due to lack of availability in some countries. Newer strategies for prevention include vaccine development.

Anti-Infective Agents↗