A Blue Spectral Shift of the Hemoglobin Soret Band Correlates with the Age (Time Since Deposition) of Dried Bloodstains

The ability to determine the time since deposition of a bloodstain found at a crime scene could prove invaluable to law enforcement investigators, defining the time frame in which the individual depositing the evidence was present. Although various methods of accomplishing this have been proposed, none has gained widespread use due to poor time resolution and weak age correlation. We have developed a method for the estimation of the time since deposition (TSD) of dried bloodstains using UV-VIS spectrophotometric analysis of hemoglobin (Hb) that is based upon its characteristic oxidation chemistry. A detailed study of the Hb Soret band (λmax = 412 nm) in aged bloodstains revealed a blue shift (shift to shorter wavelength) as the age of the stain increases. The extent of this shift permits, for the first time, a distinction to be made between bloodstains that were deposited minutes, hours, days and weeks prior to recovery and analysis. The extent of the blue shift was found to be a function of ambient relative humidity and temperature. The method is extremely sensitive, requiring as little as a 1 µl dried bloodstain for analysis. We demonstrate that it might be possible to perform TSD measurements at the crime scene using a portable low-sample-volume spectrophotometer

Counter models and dependent renewal point processes related to neuronal firing

The mechanism of formation of neuronal spike trains is studied on the basis of some counter models as well as the dependent models proposed by ten Hoopen and Reuver. The statistical properties of the response-yielding events are explicitly obtained and some theorems dealing with the criteria for the response-yielding events to be distributed exponentially are deduced

Facile enolate alkylation of norbornenones

A facile direct enolate aikylation of norbornenones with various alkyl halides using HMPA as co-solvent is reported

Renewal point processes and neuronal spike trains

The interaction between a recurrent process and another point process generated by the former is considered in the light of a model proposed by ten Hoopen and Reuver. It is shown that the results of ten Hoopen and Reuver can be generalized in a direct manner using the techniques of point processes

Acid catalyses fragmentation of 7,7-dimethoxy norborneols. A rapid entry to 5-substituted 2-cyclopentenones

A facile method for the synthesis of 2-cyclopentenones from the acid catalysed fragmentation of 7,7-dimethoxy 5-norbornen-2-ols and their derivatives is reported