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Dr. Devidas S. Bhagat
Assistant Professor, Chemistry
Dept. of Forensic Chemistry and Toxicology,
Govt. Inst. of Forensic Sci. Aurangabad 431 004
Email:
One of the most common types of physical evidence found at crime scenes is a fingerprint.
Latent Fingerprints (LFPs) continue to play a very important role in personal identification in
criminal forensics. It is found on various objects at the crime scene side and is used to identify the
suspect or criminal and link them to the crime scene, weapon, or object. When the finger touches
any surface, the sweat from these pores gets deposited in form of contours, which are the mirror
image of the ridge patterns. LFPs have the unique impressions of various loops, whorls, and arches
left behind when a finger comes in contact with a surface and it is formed due to the deposition of
colorless sweat. LFPs residues consist of secretions of the eccrine (sweat), sebaceous, and
apocrine glands present on the palm, head, and nose. Sweat contains 98% water, 0.5% minerals,
and 0.5% other organic compounds. Eccrine sweat consists of proteins, urea, amino acids, uric
acid, lactic acid, sugars, creatinine, and choline, while sebaceous sweat consists of glycerides,
fatty acids, wax esters, squalene, and sterol esters. Fingerprint samples also have unique chemical
contents that can be used to extract valuable information about the person or persons of interest.
Fingerprints are developed on the hands of individuals in the time of the embryo's development
stage from the 9th and 24th week.
The science of developing visible representations of LFPs dates back more than a century,
and the number and type of these techniques have steadily increased. From an imaging
perspective, the goal of developing latent fingerprints is to maximize sensitivity, contrast, and
selectivity. The method of choice is often dictated by the nature of the substrate on which the print
is deposited; substrate porosity, reactivity, and other properties must all be taken into consideration
when choosing an existing method or developing a new LFPs on the various surface. Apart from
imaging, another consideration of increasing importance is that the development technique should
not compromise any chemical information that may be contained in the print. An emerging area in
fingerprint development is the application of organic dyes for the development of latent
fingerprints on porous, non-porous, and wet surfaces by powder dusting methods. Most of these
novel methods offer high sensitivity and improved contrast pattern of substrates, and with high
resolution.
The scientific community plays a dynamic role in the development of forensics in various
dimensions. These topics have always been under constant investigation and development of
Latent fingermarks using numerous dyes for the last three to four decades. Every year hundreds of
dyes are reported which have excellent applications in the development of latent fingerprints. The
most common dye like ninhydrin and azo dye is used for the development of latent prints. Also,
The dyes like ninhydrin, Rhodamine, Nitro dye derivatives, ninhydrin, Numerous azo dye
derivatives, acidic dye, dye basic dye, alizarin, triaryl methane dye, and indigo dye are used for the
development of finger marks. The research community every year develop some novel derivatives
having significant application in the visualization of a latent fingerprint.
devidas.bhagat@gov.in
Recent Trends of Dyes in Latent Fingerprint Development
ACT News Letter 18, September - December - 2020ACT News Letter 18, September - December - 2020
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The field of developed chemical fingerprints has been analyzed by empirical
investigations. The chemistry has been investigated out of intellectual curiosity or as an attempt to
improve the protocol. The challenge for chemistry instructors, researchers, forensic experts, and
students is to develop novel dyes having unique properties.
References:
1. J. Brent Friesen, J. Chem. Educ. 2015, 92, 497-504
2. C. Huynha, J. Halamek, Trends Anal. Chem., 2016, 82, 328-336
3. D.S. Bhagat, et. al, Mater. Today, 2020, 29, 1223-1228
A 3D printed lock and key model to aide teachers to teach
Chemistry to visually challenged students
Prof B S Balaji
School of Biotechnology,Jawaharlal Nehru University,
New Delhi 110067
Email ; bsbalaji@mail.jnu.ac.in
According to a report published by the National Programme for Control of Blindness
(NPCB), India is home to a third of the world's blind population (about 10 million).The challenges
faced by the blind people are numerous. Even teachers of such students face various limitations to
teach these children.
In order to alleviate the problems faced by visually challenged people, various support
efforts had been carried out by Government of India. Despite these policy measures, when it comes
to education, the visually impaired are still not adequately benefited. A survey conducted by the
National Council of Educational Research and Training (NCERT) shows, vast majority of the blind
children (around 70 %) are not enrolled in any form of education system.
ACT News Letter 18, September - December - 2020ACT News Letter 18, September - December - 2020