Visualization of dyes on thin-layer chromatography plates by means of the argon ion laser.

A simple method for the detection of nanogram amounts of dyes by means of their fluorescence in the visible region of the spectrum is described. To stimulate the fluorescence, an argon ion laser with principal lines of 514.5 nm and 488.0 nm is used. The sensitivity of the technique allows the visualization of an amount of dye smaller than could be detected with either visible absorbance or ultraviolet stimulated fluorescence.

Close proximity gunshot residues.

Intuitively, a hand held in close proximity to a firearm at the instant of discharge will intercept a significant amount of gunshot residue, even though the hand did not actually come into contact with the weapon. There is, however, little information specifically described in the forensic science literature concerning the residue levels which might be encountered in such an instance. The present work confirms that antimony levels consistent with an individual having fired or handled a firearm may be intercepted by a hand held in close proximity.

The effect of tempered glass on bullet trajectory.

It was determined that tempered glass automobile windows may severely influence the trajectory of .38 Special projectiles. In replicating an actual case situation, deflections as great as 26.4 degrees were observed with jacketed hollow-point ammunition, and as high as 10.8 degrees for lead ammunition.

The interpretation of impact fractures in glassy polymers.

While this study was not exhaustive of the area of impact fractures in glassy polymers, it does demonstrate that there are some significant differences between fractures in polymers and those encountered with glass. Those differences can be summarized as follows: (1) the occurrence of pronounced, highly curved hackle marks, which could in many instances be mistaken for conchoidal marks;(2)the appearance of the beveled edges bordering the cratering on the side opposite origin of force; and (3) a more apparent tendency toward an inverse relationship of muzzle velocity and energy to radial fracture length and degree of curving along crater boundaries. The physical laws applicable to the fracture of glass are identical to those extant in the fracture of glassy polymers; no new forces are at play. All of the differences are capable of being explained in terms of the differences in flexibility and flow between glass and polymers, and the resulting differences in tension development and fracture propagation.

Enhancement of the luminol test by means of light amplification.

The type of device commonly referred to as a "starlight scope" will amplify available light by a factor of approximately 17 000. The use of this device will permit an image to be formed by exceedingly small amounts of blood when reacted with luminol reagent. Modification of the apparatus is necessary to permit focusing at short distances.

Visual Color Comparisons in Forensic Science.

Color is used extensively in forensic science for the characterization and comparison of physical evidence, and should thus be well understood. Fundamental elements of color perception and color comparison systems are first reviewed. The second portion of this article discusses instances in which defects in color perception may occur, and the recognition of opportunities by means of which color perception and color discrimination may be expressed and enhanced. Application and limitations of color comparisons in forensic science, including soil, paint, and fibers comparisons and color tests, are reviewed.

Kinetics of heroin deacetylation in aqueous alkaline solution and in human serum and whole blood.

A kinetic study of heroin hydrolysis in alkaline aqueous solution at room temperature was conducted by a gas chromatographic method to measure the consecutive reactions of diacetylmorphine to monoacetylmorphine and of monoacetylmorphine to morphine. A first-order reaction was observed in both instances, and the rate for the deacetylation of heroin was greater than that of monoacetylmorphine. The rates of in vitro hydrolysis of diacetylmorphine in human whole blood and in serum were compared by the same method. Diacetylmorphine was hydrolyzed twice as rapidly in blood as in serum. While morphine was an end product of hydrolysis in the blood, it was absent in the serum.