Frog

An invaluable glossary of over 300 words, from aberration to zoom by way of crippled lead-frog tests and output bus drivers . 

Fig. 1. The time evolution (top) and average cumulative difference (bottom) associated with the central dihedral angle of butane r (defined by the four carbon atoms), for trajectories differing initially in 10 , 10 , and 10 Angstoms of the Cartesian coordinates from a reference trajectory. The leap-frog/Verlet scheme at the timestep At = 1 fs is used in all cases, with an all-atom model comprised of bond-stretch, bond-angle, dihedral-angle, van der Waals, and electrostatic components, a.s specified by the AMBER force field within the INSIGHT/Discover program.

An example of a symplectic/time-reversible method is the Verlet (leap-frog) scheme. This method is applicable to separataP Hamiltonian systems of the... 

HyperChem employs the leap frog algorith m to integrate the et uaLioMs of motion. Th is algoritlim updates the positions of atom s and the velocities for the n e.x 1 time step by tli is ca leu la lion (equation 26). 

The leap-frog algorithm uses the simplest central difference I or-m n la for a derivative... 

A.s described previously, the Ixiap-frog algorithm for molecular dynamics requires an in itial eonfiguration for the atoms and an initial set of velocity vectors v. /2. fh ese in itial velocities can com e... 

Bioactive amines are also widespread in animals Avariety of structures and properties have been found in substances isolated from frogs for example One called epibatidine is a naturally occurring painkiller... 

Isolated from frogs of the Dendrobatidae family Related compounds have also been isolated from certain ants )... 

Animal aquaculture is concentrated on finfish, moUuscs, and cmstaceans. Sponges, echinoderms, tunicates, turtles, frogs, and alligators are being cultured, but production is insignificant in comparison with the three principal groups. Common and scientific names of many of the species of the finfish, moUuscs, and cmstaceans currently under culture are presented in Table 2. Included are examples of bait, recreational, and food animals. 

Health and Safety Factors. The following toxicities have been reported for cyanoacetic acid oral LD q (rat) 1500 mg/kg subcutaneous LD q (rabbit), 1900 mg/kg and subcutaneous LD q (frog) 1300 mg/kg (29). Eor ethyl cyanoacetate the following toxicities have been reported interperitoneal LD q (mice), 750 mg/kg subcutaneous LD q (rabbits), 1500 mg/kg and subcutaneous LD q (frogs), 4000 mg/kg. 

The only reported toxicity data on zinc fluoride in the NIOSH RTECS file is a LD q of 280 mg/kg for subcutaneous adniinistration in frogs. 

Another class of 5-selective peptides, isolated from extracts of frog skin, is the deltorphins. These compounds are based on the stmcture... 

Relative to procaine. Data are derived from isolated frog sciatic nerve. 

Aquatic toxicity is reported in mg/L for Pimepha/espromealas (fathead minnow), 69-h LC q 7650 (17) for Daphnia magna (water flea), 48-h EC q 3310 (18) for Mjriophjllum spicatum (water milfoil), phytotoxicity (EC q for growth) 5962 (19) and for Pana breviceps (frog), no observed effect concentration (NOEC) 400 (20). LC q and EC q are lethal and effect concentrations, respectively, for 50% of the subjects tested. 

The amphibian metamorphosis test is based on the abiUty of thyroid hormones to induce precocious transformation of a tadpole into a frog or of the axolod into a salamander. It is rarely used because of solubiUty problems and the difficulty of applying the results to humans. 

Ringer s Lactate. In 1883, it was discovered that the excised ventricle of the frog would beat for some hours if suppHed with an aqueous solution of sodium, potassium, and calcium salts. The concentration of potassium and calcium was found to be critical, whereas the amounts of the anions had htde effect on the frog heart. The composition of this saline, coined Ringer s solution, is given in Table 1. Many years later it was shown to be very close to that of frog plasma. 

Vapors of both benzal chloride and benzotrichloride are strongly irritating and lacrimatory. Reported toxicides appear in Table 3. Also, for benzotnchlonde, the lowest pubflshed lethal dose (frog) is 2150 mg/kg (69) and the toxic dose level (inhalation rats) is 125 ppm/4 h (69). 

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