Biopsy and Tissue Processing Artifacts in Oral Mucosal Tissues

ABSTRACT Artifact refers to an artificial structure or tissue alteration on a prepared microscopic slide—the result of an extraneous factor. It can result in alteration of normal morphologic and cytologic features that may occur as a result of the way the tissue has been handled, right from the time the biopsy, which is surgically obtained till the entire histopathological procedures of fixation, processing, embedding, sectioning and staining are performed on it. The procedures themselves subject to human and material errors resulting in an artifact may interfere with an adequate diagnosis or render the tissue to be undiagnosable. The present review provides in depth knowledge on the mismanagement of tissue during different biopsy sampling techniques and various processing procedures leading to the appearance of artifacts. Such familiarization in turn will contribute to knowledge of the material and instruments required for correct biopsy performance in dentistry, as well as of the material required for correct sample storage, transport and processing thereby necessitating stringent precision in technique at every step to enable an accurate diagnosis. How to cite this article Kumar K, Shetty DC, Dua M. Biopsy and Tissue Processing Artifacts in Oral Mucosal Tissues. Int J Head Neck Surg 2012;3(2):92-98.

Extension of the Two Parametric Approach to Fatigue Crack Growth in Intermetallics

Fatigue crack growth in intermetallics and their composites published in the literature have been examined in the light of the new concepts developed by the authors. It is shown that the two parametric approach can adequately account for the observed behavior without resorting to an extraneous factor such as crack closure. Implication of the two parametric approach in design is discussed.

BIOASSAY OF ANTIBIOTIC P-9 BY THE DIRECT RESPONSE OF STEM RUST OF WHEAT

A simple medium was found for the production of antibiotic P-9 used in experiments for the control of stem rust of wheat.A rust-infection bioassay method for the estimation of the potency of different production lots of filtrate was developed; potency was measured as the proportionate inhibition of stem rust (Puccinia graminis Pers. f. sp. tritici Erikss. & Henn. race 15B) infection on wheat seedlings in relation to log concentration of the material under test. The data from the bioassays took the form of a sigmoid curve when the concentrations were plotted arithmetically and of a straight line when they were plotted logarithmically. The slope of a weighted mean regression line based on 11 assays was regarded tentatively as characterizing pure antibiotic P-9.When the data of the 11 assays were adjusted for differences in potency between assays, the weighted mean regression line was statistically significant at the 1% point of probability. It is hoped that the slope of this line characterizes the pure antibiotic P-9 sufficiently well to be a useful tool in estimations of the relative purity of fractions obtained in the progressive purification of the antibiotic. Regression lines that differ from it substantially in slope may be suspected of influence from some extraneous factor.

The Eliminant of a Set of Quaternary Quadrics

1. The “dialytic” method of elimination, in the case of more than one variable, is not without its drawbacks, as most mathematicians know. The requisite derived equations are not always easily obtained, the difficulty being due as often to the existence of too many as of too few; and, when this has been got over, it not unfrequently happens that the order of the resulting determinant is alarmingly high, and unaccompanied by any hope of a successful guess as to the character of the extraneous factor. The discoverer's original paper affords sufficient testimony of this, and very little has been done since its appearance to put matters on a sounder footing. The most noteworthy improvement, due to Cayley, is more interesting theoretically than practically, his main object being the detection of the extraneous factor when there is an over-plus of equations. Nothing, indeed, will be found more conducive to an understanding of the limitations of the method than a careful comparison of the application of this process of Cayley's to the problem of eliminating x, y, z from the three ternary quadricswith Sylvester's original treatment of the same problem, and the latter especially as commented on in footnotes by the author himself.2. The want of definiteness in the mode of arriving at the exact number of derived equations is not without its compensating advantage, as it leaves that scope for the exercise of ingenuity which is half the charm of mathematical work.