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In this paper, we propose and analyse a predator-prey model with disease in prey. We assume that a portion of healthy prey takes refuge to avoid predation. We find the biologically feasible equilibrium points and their stability criteria by using linearization technique. We also perform Hopf bifurcation analysis around the co-existing equilibrium point. We use substantial numerical simulation to verify our theoretical results and to investigate rich dynamics that are not possible to achieve analytically. We illustrate rich dynamics such as Hopf bifurcation. chaos, bistability, and others using one and two parameter bifurcation diagrams. We find that disease invasion in prey can produce chaos by inducing period-doubling bifurcation. but refuge can reduce chaos by causing period-halving bifurcation. We also observe that refuge can reduce the prevalence of disease in the Prey population. [ABSTRACT FROM AUTHOR]

1. (2R,3S)-[U-14C,³H1]- and (2R,3R)-[U-14C,2,3-³H2] Cysteine hydrochlorides have been separately synthesized. The latter compound has been shown to have uniform distribution of tritium between C-2 and C-3. 2. The above cysteines and (2R)-[U-14C,3,3,3′,3′-³H4]cystine have been converted to samples of penicillin G by Penicillium chrysogenum. 3. Incorporation results indicate that all but 14% of the tritium is lost from the (2R,3S)-[3-³H1]isomer; that 42% of tritium is retained by the non-stereospecifically C-3 tritiated cystine; and that 58% of tritium is retained by the (2R, 3R)-[2,3-³H2]cysteine hydrochloride has indicated that in fact about 87% of the original C-3 tritium of cysteine is retained at C-5 of penicillin G. 5. The results indicate stereospecificity in the cyclisation giving rise to the β-lactam ring in penicillin G in nature with loss of the 3-pro-S-hydrogen and retention of the 3-pro-R-hydrogen of cysteine. Thus there is net retention of stereochemistry in the cyclisation. [ABSTRACT FROM AUTHOR]