Sweat Fingerprints Research Articles

Toward multidimensional information: A derivatization-free UHPLC-QqQ MS/MS method for amino acid components of fingerprint.

The analysis of fingerprint chemical composition is a meaningful way to excavate the multidimensional information of fingerprint, including the donor profiling information and the age of a fingerprint, which broadens the evidential values of fingerprint, especially for the partial and distorted fingerprint. But the research remains still in the pilot phases or is ongoing. Amino acids are the dominant organic substances in latent sweat fingerprint and influenced by many donor factors. Hence, their content reflects personal information of donors. Forensic science will be revolutionized if suspects can be individualized by their amino acid content. The diverse nature, distinct physicochemical properties, and ultra-micro levels of amino acids present in fingerprints make it hard to detect. A high sensitivity method for detecting and quantifying multiple amino acid components is required. UHPLC-QqQ MS/MS offers high sensitivity, high separation, simultaneous multicomponents detection, and no derivatization, making it an ideal method for detecting and analyzing amino acids in fingerprints. Therefore, in this study, we propose and validate an efficient UHPLC-QqQ MS/MS method for the extraction and analysis of 13 amino acids from fingerprint. We compared the results of amino acids of 10 different substrates and found that the inherent amino acids in most porous substrates would have been extracted along with the fingerprint amino acids, making them unsuitable for quantitative amino acid analysis. Instead, plastic sheets are ideal substrates for laboratory studies. Then, extensive experiments were conducted among 30 donors for multidimensional information analysis. The type of samples analyzed were eccrine-rich fingerprints. A Binary Logistic Regression (BLR) model was developed, and the female and male donors were successfully differentiated by amino acids in fingerprints. Two other mathematical models were also developed to verify the accuracy, and all three different mathematical models were able to identify donors of different genders with over 90% accuracy. This demonstrates that amino acids have the potential to provide more information for donors as metabolic markers. In the future, we will conduct a series of experiments to analyze more multidimensional information for individual identification by amino acid content in the fingerprint.

Fluorescence spotting of latent sweat fingerprints with zinc oxide carbon dots embedded in a silica gel nanopowder: a green approach

In this research article, the green synthesized CZnO-dots/Si nanopowder is expended as the LFs fluorescent tagging agent by the dust blowing method.

Ultrasound induced synthesis of dual phased hierarchical ZrO2:Eu3+ architectures: Fluorescent based sensor for rapid visualization of latent fingerprints

Red emitting ZrO2:Eu3+ (1–7 mol %) nanophosphors were fabricated via ultrasonication route with Aloe Vera gel as a bio-surfactant. The sonication time engineered both the crystal structure and morphology of the prepared nanophosphor: shorter sonication time leads to the synthesis of tetragonal phase, while -longer sonication time favors the formation of cubic ZrO2 phase. A plausible growth mechanism of the architectures that implies aggregation via oriented attachment followed by an Ostwald ripening was proposed. The photoluminescence results showed the characteristic emission peaks of Eu3+ ions at ˜ 591 nm (5D0 → 7F1), 606 nm (5D0 → 7F2), 661 nm (5D0 → 7F3) and 712 nm (5D0 → 7F4). The photometric results clearly evident that the nanophosphors emit pure red color with high purity, which signify its use as a warm red component in WLEDs applications. The - powder dusting strategy was followed for the visualization of sweat latent fingerprints using optimized ZrO2:Eu3+(5 mol %) nanophosphor on many surfaces. Most essential type 1–3 ridge characteristics were clearly revealed with high sensitivity, selectivity and low background hindrance. The adopted method was simple and environment friendly for sweat fingerprint development, and promising outlook in criminal investigation and forensic science.

Сurrent Issues in Sebaceous Sweat Fingerprint Residue Visualization on Fired Cartridge Cases

This article focuses on issues concerning discovery of hands deposits on cases fred with certain models of fre weapons – 5.45 mm assault rifle АК-74М, 9 mm Makarov gun, 7,62 mm TT gun. Five persons left in turn on each of the above ammunition rounds intentionally qualitative hand traces, following which a shot was fred. After the shot the fre shot cases were collected and packed, avoiding contact between side surfaces and package material. The possibilities of discovery hand deposits on fred cases were determined by using reductive-oxidative and physical-chemical methods. The mechanism of “latent degradation” of hand deposits on cases formed before fring caused by the influence of the shot fact (high temperature, static and dynamic power contact of fred case with gun chamber walls) has been reviewed.

DNA Identification from Sebaceous Sweat Fingerprint Deposits on Corpse Integuments

The paper presents the results of a pilot molecular genetic study of sweat and oil residue left by the fingertips and hand palms of male volunteers (donors) on various regions of the skin surface of dead bodies (recipients) of both sexes. In cases of contact with female recipients donor-specific allele combinations were obtained for only 11.6% of autosomal loci and 12.9% of Y-chromosomal loci. Donor-specific traits were absent in 68.4% of autosomal loci and 87.1% of Y-chromosomal loci. In cases of contact with male recipients the full genetic profile was obtained for 18.6% of autosomal loci, and 64.2% of loci showed a lack of donor-specific alleles. Meanwhile, allelic combinations specific to female recipients were encountered in 40.5% of autosomal loci, and to male recipients – in 34.2% of autosomal loci. Results demonstrate poor adhesion of sweat and oil compounds from donors’ hands to the corpses’ skin, probably due to significant temperature differences between contact surfaces.

Synthesis of benzimidazole sweat fingerprint fluorescent developer and fluorescent effect

In this paper, benzimidazole fluorescent compounds (compound 1 and compound 2) containing hydroxymethyl and carboxyl substituents were synthesized by replacing salicylaldehyde and substituted ortho- phenylenediamine.By measuring the spectral properties of these fluorescent compounds, the influence of different substituents on the fluorescence properties of these fluorescent compounds was investigated and the fluorescence effect of these fluorescent compounds as a fluorescent latent agent for sweat fingerprinting was also investigated.The obtained hydroxymethyl and carboxyl substituted benzimidazole sweat latent fingerprints have good adsorption performance, remarkable fluorescence effect and strong stability, therefore, they can be widely used.This research also expands the research and application range of benzimidazole derivatives and it has very important research value in the field of criminal detection technology.

The Effect of Varying the Composition of Fingerprint Sweat Deposits on the Corrosion of Brass and Fingerprint Visibility.

Corrosion of α-phase brass by sebaceous sweat fingerprint deposits produced identifiable impressions in a majority of samples (n = 40) 4 days after deposition. Combining sebaceous with eccrine sweat yielded a greater percentage of identifiable fingerprint deposits, although this increase was not statistically significant. Production of identifiable fingerprints from eccrine sweat deposits was dependent on the sampling time of year with deposits taken during summer months giving similar percentages of identifiable fingerprints to sebaceous deposits. A statistically significant positive correlation was found between elapsed days after deposition and identifiable eccrine (ρ = 0.787, p < 0.05), sebaceous (ρ = 0.724, p < 0.05), and eccrine/sebaceous mixture (ρ = 0.908, p < 0.01) fingerprints deposited during summer months. The summer increase in the percentage of identifiable eccrine sweat deposits was statistically significant compared to winter eccrine deposits (p < 0.0001). Observations were consistent with results obtained from artificial sebaceous and eccrine sweat.

Visualization of Sweat Fingerprints on Various Surfaces Using a Conjugated Polyelectrolyte.

A conformation-variable conjugated polyelectrolyte responding to oppositely charged biomolecules was examined as an imaging agent for the detection of latent fingerprints (LFPs). Sulfonated poly(diphenylacetylene) (SPDPA) produces high-resolution fluorescence (FL) LFP images by simple wetting of the target objects with the polymer solution without any additional treatment. SPDPA readily interacts with LFP sweat components (especially amino acids) via electrostatic interactions, leading to significantly enhanced FL images in a "turn-on" mode. The FL emission enhancement was examined in a model reaction between SPDPA and an amino acid standard. Visualization with SPDPA is effective on various surfaces, including both rough (paper) and smooth (glass and plastic) ones. Moreover, SPDPA readily interacts with extremely thin sweat LFPs, especially on smooth glass surfaces.

266 nm陶瓷激光器反射照相在指纹显现中的应用

本文研究潜在指纹显现的新技术，用自主研发的266 nm短波紫外陶瓷激光器作为光源照射检材，通过反射照相方法显现各种非渗透性客体表面的潜在指纹。紫外陶瓷激光器能有效显现出光滑客体表面的潜在指纹，并且油脂指纹检出率高于汗液指纹检出率。陶瓷材料由于其良好的化学稳定性、耐高温性、尺寸稳定性、光漫反射特性等优点，利用该266 nm短波紫外陶瓷激光器可以显现非渗透性客体表面的潜在指纹，在刑侦领域上有较好的应用前景。 This paper describes visualization of latent fingerprints by 266 nm ultraviolet ceramic laser. Self-made 266 nm ultraviolet laser with a ceramic gain medium was used to illuminate the latent fingerprints on the non-porous substrates. The images were recorded by ultraviolet camera through reflection photography. The results showed that the marriage of ultraviolet ceramic laser and reflection photography was an effective method on visualization of latent fingerprint on non-porous substrates. The visualization rate of oil fingerprints is higher than the sweat fingerprints. Ceramic materials have the advantages of good chemical stability, high-tem- perature resistance, size stability and light diffuse reflection. The 266 nm ultraviolet ceramic laser could be adopted to the visualized latent fingerprints on the non-porous substrates. The ultraviolet ceramic laser operating at 266 nm has potential application in the field of criminal investigation.

Immunological Multimetal Deposition for Rapid Visualization of Sweat Fingerprints

AbstractA simple method termed immunological multimetal deposition (iMMD) was developed for rapid visualization of sweat fingerprints with bare eyes, by combining the conventional MMD with the immunoassay technique. In this approach, antibody‐conjugated gold nanoparticles (AuNPs) were used to specifically interact with the corresponding antigens in the fingerprint residue. The AuNPs serve as the nucleation sites for autometallographic deposition of silver particles from the silver staining solution, generating a dark ridge pattern for visual detection. Using fingerprints inked with human immunoglobulin G (hIgG), we obtained the optimal formulation of iMMD, which was then successfully applied to visualize sweat fingerprints through the detection of two secreted polypeptides, epidermal growth factor and lysozyme. In comparison with the conventional MMD, iMMD is faster and can provide additional information than just identification. Moreover, iMMD is facile and does not need expensive instruments.

Immunological Multimetal Deposition for Rapid Visualization of Sweat Fingerprints

A simple method termed immunological multimetal deposition (iMMD) was developed for rapid visualization of sweat fingerprints with bare eyes, by combining the conventional MMD with the immunoassay technique. In this approach, antibody-conjugated gold nanoparticles (AuNPs) were used to specifically interact with the corresponding antigens in the fingerprint residue. The AuNPs serve as the nucleation sites for autometallographic deposition of silver particles from the silver staining solution, generating a dark ridge pattern for visual detection. Using fingerprints inked with human immunoglobulin G (hIgG), we obtained the optimal formulation of iMMD, which was then successfully applied to visualize sweat fingerprints through the detection of two secreted polypeptides, epidermal growth factor and lysozyme. In comparison with the conventional MMD, iMMD is faster and can provide additional information than just identification. Moreover, iMMD is facile and does not need expensive instruments.

Studies on the development of latent fingerprints by the method of solid–medium ninhydrin

A new series of fingerprint developing membrane were prepared using ninhydrin as the developing agent, and pressure-sensitive emulsifiers as the encapsulated chemicals. The type of emulsifier, plastic film, concentration of the developing agent, modifying ions and thickness of the membrane were studied in order to get the optimized fingerprint developing effect. The membrane can be successfully applied to both latent sweat fingerprints and blood fingerprint on many different surfaces. The sensitivity of the method toward the latent sweat fingerprint is 0.1mg/L amino acid. The membrane can be applied to both porous and non-porous surfaces. Fingerprints that are difficult to develop on surfaces such as leather, glass and heat-sensitive paper using traditional chemical methods can be successfully developed with this membrane.

Comparative Study on Sweat Fingerprints Photographic Effects between Full-Band CCD and UV Observing Photograph Systems

Using the full-band CCD (PL4240 UV, FLI) and Yunnan Zhihai ultraviolet observation camera system (UVYNZH-II) shoot sweat fingerprints on A4 wrapper and A4 printing paper, to comparatively analyze the effects these two camera systems. The clarity and contrast of ultraviolet image captured from Full-band CCD is better than from UV observation camera system, but both devices are able to reflect the fingerprint ridge characteristics. For sweat fingerprints, it is better for the full-band CCD, but under good conditions for sweat fingerprints bridges, UV observation camera system can basically meet the requirements of sweat fingerprint UV shooting.

Synthesis of Water‐Soluble, Multicolored Fluorescent ZnxCd1−xSe Quantum Dots for Developing Latent Fingerprints

AbstractWater‐soluble ZnxCd1−xSe quantum dots (QDs) with different amounts of Cd dopant are synthesized with 3‐mercaptopropionic acid as a modifier under ambient conditions. Hydrazine hydrate is used as the surface stabilizer and pH adjuster during preparation. The effect of dopant amount, initial pH values, and heating time on the fluorescence properties are systematically studied. Based on the emission wavelength shift of ZnxCd1−xSe QDs from 430 to 578 nm, the colors of these QDs are adjustable from blue to orange. This adjustment is beneficial for developing sweat fingerprints on scotch tape. Fresh blood fingerprints on foil, ceramic tile, black plastic, scotch tape, and old bloody fingerprints on black ceramic tile are developed by the QDs. The results show that Zn0.77Cd0.23Se QDs (calculated composition; measured composition: Zn0.83Cd0.17Se) are the most effective material for developing blood fingerprints and is even superior to the traditional tetramethylbenzidine reagent.

The relationship between anxiety, fatigue and spontaneous recovery in stuttering

There is apparently no formalized hypothesis regarding the antecedents of spontaneous recovery of stuttering. Since adaptation and recovery appear to be functionally related, antecedents of adaptation have been considered to be antecedent to spontaneous recovery. Two disparate hypotheses of adaptation which have experimental support are the anxiety hypothesis and the fatigue hypothesis. The present study was initiated to investigate the relationship of anxiety and/or fatigue, if any, to spontaneous recovery. Twenty-one subjects (stutterers) participated in four conditions. Each condition consisted of eight oral readings of a passage. The experimental variables were introduced into the respective conditions after the fifth oral reading. They were: (I) no rest, same passage; (II) rest, same passage; (III) no rest, different passage; and, (IV) rest, different passage. Palmar sweat fingerprints of anxiety were taken concurrently with the first thirty seconds of trials one, three, five, six, seven and eight for all conditions. The results of the investigation led to the conclusions that: (1) there was no necessary relationship between a change in the frequency of stuttering and a change in the anxiety level ; (2) the Hullian concepts of reactive and conditioned inhibition appeared to provide a meaningful approach to the question of spontaneous recovery of stuttering behaviour.