Rabbit ear

There is little experience with the von Niessen method, but for most molecules the remaining three schemes tend to give very similar LMOs. The main exception is systems containing both a- and vr-bonds, such as ethylene. The Pipek-Mezey procedure preserves the cr/yr-separation, while the Edmiston-Ruedenberg and Boys schemes produce bent banana bonds. Similarly, for planar molecules which contain lone pairs (like water), the Pipek-Mezey method produces one in-plane cr-type lone pair and one out-of-plane yr-type lone pair, while the Edmiston-Ruedenberg and Boys schemes produce two equivalent rabbit ear lone pairs. 

Rabbit Ear Bioassay for Acnegenic Activity. Acnegenic activity of 2-7-DCDD, 1,2,3,4-TCDD, 2,3,7,8-TCDD, HCDD, and OCDD was tested by applying 0.1 ml of either a solvent solution or the supernatant of a solvent suspension of each compound to the inner surface of the rabbit s ears five days a week for four weeks. The ears were examined weekly for signs of chloracne, inflammation, and hyperkeratosis. The responses were divided into five categories (1) none, (2) very slight, (3) slight, (4) moderate, and (5) severe. 

Acnegenic Response. Both 2,3,7,8-TCDD and HCDD produced chloracne in the rabbit ear bioassay as indicated by the formation of comedones. Solutions of 2,3,7,8-TCDD (sample c) in benzene ranging in concentration from 0.04 /xg/ml to 400 ju,g/ml produced a positive response with severity increasing with concentration. A negative response was obtained with a solution of 0.004 ju,g/ml. In contrast, a chloroform solution of 1,2,3,4-TCDD, 50 jug/ml, did not produce a positive response. With HCDD (samples a, b, c, and d), a response was produced by solutions of 10 to 50 ju,g/ml in chloroform and dimethoxyethane. Chloroform extracts from 10% suspensions of 2,7-DCDD or OCDD were negative, indicating that these have a low order or possibly no acnegenic activity. 

There have been recent studies on the importance of NO in modulating skin blood flow in both normal animals and in inflammatory models. Khan etiU. (1993), using laser-Doppler techniques, showed that the NOS inhibitor L-NAME inhibited rabbit ear blood flow. It was possible to do this chronically for up to 2 weeks using implanted osmotic pumps. Pons et id. (1993) also used laser Doppler to show that the vasodilator eflFect of LPS in rabbit skin, which mimics the efiect of Gram-negative bacteria, was likely to involve both i-NOS and IL-1. We have already discussed the damaging eflPects of neutrophils... 

Chronic inhibition of nitric oxide production augments skin vasoconstriction in the rabbit ear. J. Cardiovasc. Pharmacol. 22, 290-296. 

C. Padula, F. Sartori, F. Marra, and P. Santi, The influence of iontophoresis on acyclovir transport and accumulation in rabbit ear skin. Pharmaceutical Res. 22, 1519-1524 (2005). 

Laing, M. 1987. No rabbit ears on water. J. Chem. Educ. 64, 124-128. 

W3. Wood, S., Jr., Pathogenesis of metastasis formation observed in the rabbit ear chamber. Arch. Pathol. 66, 550-558 (1958). 

L. Celesti, C. Murratzu, M. Valoti, G. Sgaragli, and P. Corti. The single-pass perfused rabbit ear as a model for studying percutaneous absorption of clonazepam. I. General characteristics. Methods Find. Exp. Clin. Pharmacol. 14 701-709 (1992). 

Strong, apicai MSG anomaiies were observed above the centre of the conceaied main Cu ore bodies for Bi. Copper, Pb and Zn produced both apicai and rabbit-ear anomaiies over the known buried Cu mineraiization. Siiver yieided weak rabbit-ear anomaiies at either side of the Cu orebodies (Fig. 4). However, in soii oniy the totai concentrations of Ag,Cu,Pb, and Bi increase siightiy. 

At the White Lake Cu-Zn sulfide deposit (near Flin Flon, Manitoba) no geochemical signature had been obtained from conventional soil geochemistry. Where the deposit is overlain by 23m of barren rock and 8m of glacial overburden including an upper 1m of impermeable varved clay, a strong characteristic rabbit-ear H anomaly clearly indicates the location of the orebody, as predicted by the electrochemical model (Govett 1976). 

Soil samples taken at a depth of 2-5 cm showed that where there is only one metre of Campaspe beds the anomalies are as expected very strong Pb and Zn, distinct but low Cu, rabbit-ear conduct-ance, and a triple peak This pattern gradually changes with increasing thickness of Campaspe beds and where there is 50 m of Campaspe beds the Zn anomaly remains strong, there is no Pb anomaly, the Cu anomaly is distinct but low, and there is a well defined rabbit-ear anomaly. EDTA-soluble Zn has exact-ly the same pattern as total Zn. 

In the 1960s and 1970s the use of soil geochemistry in mineral exploration led to the discovery of the now commonly observed twin-peak or rabbit-ear geochemical anomaly (Govett 1976). From the time rabbit-ear anomalies were first described they were attributed to electrochemical processes but the theory proposed at that time could only... 

Queensland, Australia (Govett Atherden 1987). That study showed strong rabbit-ear responses in surface soils in commodity elements and elevated H " in... 

Govett Atherden (1987) show Pb and Zn shallow soil geochemical data collected over the Thalanga Pb-Zn-Cu deposit. Four lines were sampled that represent burial depths of 0, 1, 30 and 50 m. The anomalies display a rabbit-ear pattern centred on the deposit regardless of overburden thickness. The magnitude of the anomalies diminishes with increasing cover and Pb diminishes more rapidly than Zn. 

This was recognized as being similar to a weak or selective extraction. Very often, the pattern of element responses over mineralization was double-peak in form and restricted to the immediate vicinity of the deposits. A few published results illustrate these donut (plan) or rabbit-ear (profile) anomalies (Barringer 1977). 

Topical application to rabbit ears three times/week for 13 weeks caused some local dermal irritation due to defatting action. ... 

Powers MB, Coate WB, Lewis TR Repeated topical applications of 1,2,4-trichlorohenzene. Effects on rabbit ears. Arch Environ Health 30 165-167, 1975... 

Cancer was first recognized as an occupational hazard in 1775 when the prevalence of scrotal cancer among London chimney sweeps was noticed. The chemical origin of this form of cancer was not universally accepted until 1922 when it was demonstrated that tumors could be induced on mouse skin using an etheral soot extract (60). Skin cancer was also noted to be an occupational hazard of workers exposed to pitch dust in the coal-briquetting industry (61) and to workers exposed to cmde tar (62). In 1915, tumors were produced in rabbits ears by prolonged application of cmde coal tar (63). Some 38 cases per year have been reported of cutaneous epithelioma in the tar distilling industry over a 25-year period up to 1945 (64). 

The orbital degeneracies noted in point 3 above and seen in Figure 2.4 reflect the symmetry of the molecule s nuclear framework. Notice that the conventional picture of two equal lone pairs in water, sometimes displayed as rabbit ears, is not supported by the energies of the two highest occupied MOs of water. In fact, the lone pairs resemble the proper group MOs shown in Figure 1.8. 

The velocity of interstitial fluid in solid tumors is often lower than the resolution of experimental techniques, which is 0. lpm/sec, except in some special tumor models. For example, Chary and Jain (1989) have examined interstitial fluid velocity in granulation tissues and VX2 mammary carcinoma grown in rabbit ear chambers, using the fluorescence recovery after photobleaching (FRAP) technique. The average velocities in both tissues are about 0.6 pm/sec. 

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