23,353 research outputs found
Quantum mechanical formalism of particle beam optics
A general procedure for construction of the formalism of quantum beam optics
for any particle is reviewed. The quantum formalism of spin-1/2 particle beam
optics is presented starting {\em ab initio} with the Dirac equation. As an
example of application the case of normal magnetic quadrupole lens is
discussed. In the classical limit the quantum formalism leads to the well-known
Lie algebraic formalism of classical particle beam optics.Comment: ReVTeX 06 pages, in Proc. of the 18th Advanced ICFA Beam Dynamics
Workshop on Quantum Aspects of Beam Physics (QABP) (15-20 October 2000,
Capri, ITALY) Editor: Pisin Chen (World Scientific, Singapore, 2002)
http://www.pd.infn.it/~khan/ and http://www.imsc.ernet.in/~jagan
The pathogenesis of Acanthamoeba infections: current status and future implications
Acanthamoeba are opportunistic protozoan parasites that can cause painful, visionthreatening
keratitis. However the pathogenesis and pathophysiology of
Acanthamoeba keratitis remain incompletely understood. Most cases of
Acanthamoeba keratitis develop as a result of poor hygiene in contact lens care but it
is unclear how amoebae transmigrate from the environment into the cornea leading to
inflammation, photophobia and blindness. Acanthamoeba keratitis has become
increasingly important in the past few decades due to increasing populations of
contact lens users. The mechanisms associated with the pathogenesis of
Acanthamoeba are highly complex, depending on the virulence properties of the
parasite, host susceptibility and the environmental conditions. Complete
understanding of Acanthamoeba pathogenesis and its associated risks factors should
allow us to design strategies for disease prevention and for the rational development
of therapeutic interventions against these devastating infections.
Acanthamoeba keratitis has become a significant problem in recent years,
especially in contact lens wearers exposed to contaminated water
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