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Seki T, Hsiao YY, Ishizawa F, Sugano Y, Takahashi Y. Establishment of a random forest regression model to estimate the age of bloodstains based on temporal colorimetric analysis. Leg Med (Tokyo) 2024; 69:102343. [PMID: 37923590 DOI: 10.1016/j.legalmed.2023.102343] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2023] [Revised: 10/10/2023] [Accepted: 10/28/2023] [Indexed: 11/07/2023]
Abstract
Bloodstain age estimation is important in forensic science. Although several studies have used spectroscopy to estimate bloodstain ages, this method has not yet been practically applied due to the need for expensive equipment and low reproducibility. Thus, we aimed to develop a bloodstain age estimation model that can be easily performed using a spectrophotometric colorimeter. First, bloodstains were prepared by placing blood obtained from five healthy volunteers on a plastic plate. The bloodstains were kept on conditions with various brightness and temperatures. Then, each bloodstain was dissolved in saline every 24 h to a final concentration of 1%, measured with a spectrophotometric colorimeter, and subjected to machine learning to generate a random forest regression (RFR) model, and finally, the prediction accuracy of the bloodstain age was verified. We also elucidated the mechanism of the color changes utilizing aminoguanidine, which is an inhibitor of Maillard reaction. Finally, we measured the time-dependent color changes of the blood fluids obtained from healthy volunteers and examined if the method could be potentially applied to estimate postmortem interval (PMI). Our results showed that the RFR model estimated the bloodstain age with no substantial assessment, and it was applicable to bloodstains, regardless of the brightness or temperature. The color changes were affected by the addition of aminoguanidine. Furthermore, the method could be applied to blood fluids, suggesting its potential usefulness for PMI estimation. Considering its feasibility, the present method could potentially be introduced to practical forensic sciences in the near future.
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Affiliation(s)
- Tomohiro Seki
- Department of Legal Medicine, Institute of Medicine, University of Tsukuba, Japan
| | - Yi-Yang Hsiao
- Department of Legal Medicine, Institute of Medicine, University of Tsukuba, Japan
| | - Fujio Ishizawa
- Department of Legal Medicine, Institute of Medicine, University of Tsukuba, Japan
| | - Yukiko Sugano
- Department of Legal Medicine, Institute of Medicine, University of Tsukuba, Japan
| | - Yoichiro Takahashi
- Department of Legal Medicine, Institute of Medicine, University of Tsukuba, Japan.
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2
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Lee S, Lee YR, Lee J, Kang HG. Discovery and validation of metabolite markers in bloodstains for bloodstain age estimation. Analyst 2023; 148:4180-4188. [PMID: 37526270 DOI: 10.1039/d3an00603d] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/02/2023]
Abstract
Bloodstain age estimation involves measuring time-dependent changes in the levels of biomolecules in bloodstains. Although several studies have identified bloodstain metabolites as markers for estimating bloodstain age, none have considered sex, age-related metabolomic differences, or long-time bloodstain age. Therefore, we aimed to identify metabolite markers for estimating the age of bloodstains at weekly intervals within 28 days and validate them through multiple reaction monitoring. Adenosine 5'-monophosphate, choline, and pyroglutamic acid were selected as markers. Seven metabolites were validated, including five previously reported metabolites, ergothioneine, hypoxanthine, L-isoleucine, L-tryptophan, and pyroglutamic acid. Choline and hypoxanthine can be used to differentiate bloodstains between days 0 and 14 after deposition at weekly intervals, whereas L-isoleucine and L-tryptophan can help distinguish bloodstains between 7 days before and 14 days after deposition. Evaluation of the changes in metabolite levels according to sex and age revealed that the average levels of all seven metabolites were higher in women on day 0. Moreover, the level of ergothioneine was significantly higher in elderly individuals than in young individuals at all time points. In this study, we confirmed the potential effectiveness of metabolites in bloodstains as forensic markers and provided a new perspective on metabolomic approaches linked to forensic science.
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Affiliation(s)
- Seungyeon Lee
- Department of Senior Healthcare, Graduate School, Eulji University, Uijeongbu, Republic of Korea
| | - You-Rim Lee
- Department of Senior Healthcare, Graduate School, Eulji University, Uijeongbu, Republic of Korea
| | - Jiyeong Lee
- Department of Biomedical Laboratory Science, College of Health Science, Eulji University, Uijeongbu, Republic of Korea.
| | - Hee-Gyoo Kang
- Department of Senior Healthcare, Graduate School, Eulji University, Uijeongbu, Republic of Korea
- Department of Biomedical Laboratory Science, College of Health Sciences, Eulji University, Seongnam, Republic of Korea.
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3
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Arrigo A, Aragona E, Battaglia Parodi M, Bandello F. Quantitative approaches in multimodal fundus imaging: State of the art and future perspectives. Prog Retin Eye Res 2023; 92:101111. [PMID: 35933313 DOI: 10.1016/j.preteyeres.2022.101111] [Citation(s) in RCA: 14] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2022] [Revised: 07/16/2022] [Accepted: 07/19/2022] [Indexed: 02/01/2023]
Abstract
When it first appeared, multimodal fundus imaging revolutionized the diagnostic workup and provided extremely useful new insights into the pathogenesis of fundus diseases. The recent addition of quantitative approaches has further expanded the amount of information that can be obtained. In spite of the growing interest in advanced quantitative metrics, the scientific community has not reached a stable consensus on repeatable, standardized quantitative techniques to process and analyze the images. Furthermore, imaging artifacts may considerably affect the processing and interpretation of quantitative data, potentially affecting their reliability. The aim of this survey is to provide a comprehensive summary of the main multimodal imaging techniques, covering their limitations as well as their strengths. We also offer a thorough analysis of current quantitative imaging metrics, looking into their technical features, limitations, and interpretation. In addition, we describe the main imaging artifacts and their potential impact on imaging quality and reliability. The prospect of increasing reliance on artificial intelligence-based analyses suggests there is a need to develop more sophisticated quantitative metrics and to improve imaging technologies, incorporating clear, standardized, post-processing procedures. These measures are becoming urgent if these analyses are to cross the threshold from a research context to real-life clinical practice.
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Affiliation(s)
- Alessandro Arrigo
- Department of Ophthalmology, IRCCS San Raffaele Scientific Institute, via Olgettina 60, 20132, Milan, Italy.
| | - Emanuela Aragona
- Department of Ophthalmology, IRCCS San Raffaele Scientific Institute, via Olgettina 60, 20132, Milan, Italy
| | - Maurizio Battaglia Parodi
- Department of Ophthalmology, IRCCS San Raffaele Scientific Institute, via Olgettina 60, 20132, Milan, Italy
| | - Francesco Bandello
- Department of Ophthalmology, IRCCS San Raffaele Scientific Institute, via Olgettina 60, 20132, Milan, Italy
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4
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Lee S, Mun S, Lee YR, Lee J, Kang HG. Validation of the Metabolite Ergothioneine as a Forensic Marker in Bloodstains. Molecules 2022; 27:molecules27248885. [PMID: 36558018 PMCID: PMC9786767 DOI: 10.3390/molecules27248885] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2022] [Revised: 12/09/2022] [Accepted: 12/13/2022] [Indexed: 12/15/2022] Open
Abstract
Ergothioneine, which is a naturally occurring metabolite, generally accumulates in tissues and cells subjected to oxidative stress, owing to its structural stability at physiological pH; therefore, it has been attracting attention in various biomedical fields. Ergothioneine has also been suggested as a potential forensic marker, but its applicability has not yet been quantitatively validated. In this study, quantitative analysis of ergothioneine in bloodstains was conducted to estimate the age of bloodstains and that of bloodstain donors. Blood from youth and elderly participants was used to generate bloodstains. After extracting metabolites from the bloodstains under prevalent age conditions, ergothioneine levels were quantified by mass spectrometry via multiple reaction monitoring. The concentration of ergothioneine in day 0 bloodstains (fresh blood), was significantly higher in the elderly group than in the youth group, but it did not differ by sex. Statistically significant differences were observed between the samples from the two age groups on days 0, 5 and 7, and on days 2 and 3 compared with day 0. The findings suggest that ergothioneine can be used to estimate the age of bloodstains and of the donor; it could be useful as a potential marker in reconstructing crime scenes.
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Affiliation(s)
- Seungyeon Lee
- Department of Senior Healthcare, Graduate School, Eulji University, Uijeongbu 11759, Republic of Korea
| | - Sora Mun
- Department of Biomedical Laboratory Science, College of Health Sciences, Eulji University, Seongnam 13135, Republic of Korea
| | - You-Rim Lee
- Department of Senior Healthcare, Graduate School, Eulji University, Uijeongbu 11759, Republic of Korea
| | - Jiyeong Lee
- Department of Biomedical Laboratory Science, College of Health Science, Eulji University, Uijeongbu 11759, Republic of Korea
- Correspondence: (J.L.); (H.-G.K.); Tel.: +82-31-951-3862 (J.L.); +82-31-740-7315 (H.-G.K.)
| | - Hee-Gyoo Kang
- Department of Senior Healthcare, Graduate School, Eulji University, Uijeongbu 11759, Republic of Korea
- Department of Biomedical Laboratory Science, College of Health Sciences, Eulji University, Seongnam 13135, Republic of Korea
- Correspondence: (J.L.); (H.-G.K.); Tel.: +82-31-951-3862 (J.L.); +82-31-740-7315 (H.-G.K.)
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Tian L, Chen H, Ma R, Zhang M. Estimating Time since Deposition of Bloodstains by Scanning Electrochemical Microscopy. ChemElectroChem 2022. [DOI: 10.1002/celc.202200434] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Affiliation(s)
- Lu Tian
- Beijing Key Laboratory for Bioengineering and Sensing Technology School of Chemistry and Biological Engineering University of Science and Technology Beijing 30 Xueyuan Road Beijing 100083 P.R. China
| | - Hongyu Chen
- Beijing Key Laboratory for Bioengineering and Sensing Technology School of Chemistry and Biological Engineering University of Science and Technology Beijing 30 Xueyuan Road Beijing 100083 P.R. China
| | - Rongliang Ma
- Institute of Forensic Science Ministry of Public Security
| | - Meiqin Zhang
- Beijing Key Laboratory for Bioengineering and Sensing Technology School of Chemistry and Biological Engineering University of Science and Technology Beijing 30 Xueyuan Road Beijing 100083 P.R. China
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Short and Long Time Bloodstains Age Determination by Colorimetric Analysis: A Pilot Study. Molecules 2021; 26:molecules26206272. [PMID: 34684853 PMCID: PMC8540217 DOI: 10.3390/molecules26206272] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2021] [Revised: 10/12/2021] [Accepted: 10/13/2021] [Indexed: 11/17/2022] Open
Abstract
Bloodstains found at crime scenes represent a crucial source of information for investigative purposes. However, in forensic practice, no technique is currently used to estimate the time from deposition of bloodstains. This preliminary study focuses on the age estimation of bloodstains by exploiting the color variations over time due to the oxidation of the blood. For this purpose, we used a colorimetric methodology in order to easily obtain objective, univocal and reproducible results. We developed two bloodstain age prediction algorithms: a short-term and a long-term useful model for the first 24h and 60 days, respectively. Both models showed high levels of classification accuracy, particularly for the long-term model. Although a small-scale study, these results improve the potential application of colorimetric analysis in the time-line reconstruction of violent criminal events.
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Identification of different body fluids through novel deep blue autofluorescence. Forensic Sci Int 2021; 327:110976. [PMID: 34478895 DOI: 10.1016/j.forsciint.2021.110976] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2021] [Revised: 08/13/2021] [Accepted: 08/21/2021] [Indexed: 11/22/2022]
Abstract
Identification of different body fluids at crime scene is imperative to know about its source and the type of crime committed. Non-invasive fluorimetric techniques for the identification of body fluids rely upon the aromatic amino acids, which are not always prevalent in many proteins. Novel fluorescence technique, known as deep blue autofluorescence (dbAF), is independent of aromatic amino acids fluorescence, and can differentiate different body fluids. Contributed mainly by carbonyl group of amino acids, this auto fluorescence shows emission in deep blue (~400-600 nm) region after exciting at the edge of the long wavelength UV range (~360--380 nm). The present study demonstrate the first ever report of deep blue autofluorescence in the identification of different body fluids like, urine, saliva, blood, semen and vaginal sample. dbAF of human body fluids were observed to be distinct from the body fluids of dog, and thus provides a prospective alternative to differentiate human and non-human body fluids. We also demonstrated that dbAF decreases over the time window of 7 days, however it was not completely diminished and still detects the different body fluids. Since all body fluids are inherently fluorescent, present technique could be a novel approach for the identification of various body fluids at crime scene during forensic investigation.
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Weber A, Wójtowicz A, Lednev IK. Post deposition aging of bloodstains probed by steady-state fluorescence spectroscopy. JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY B-BIOLOGY 2021; 221:112251. [PMID: 34229147 DOI: 10.1016/j.jphotobiol.2021.112251] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/10/2021] [Revised: 06/19/2021] [Accepted: 06/26/2021] [Indexed: 01/20/2023]
Abstract
Blood is one of the most common body fluids discovered at crime scenes involving violent actions. It is one of the most important types of forensic evidence since it allows for the identification of the individual providing that there is a match with a known DNA profile. Determining the time since deposition (TSD) can assist investigators in establishing when the crime occurred or if a bloodstain present is actually related to the investigated event. To develop a forensically sound method for determining the TSD of a bloodstain, it is necessary to understand the underlying biochemical mechanisms occurring during aging. As biochemical processes occurring in blood are necessary for the continued survival of living organisms, they are important subjects of human biology and biomedicine and are well understood. However, the biochemistry of bloodstain aging ex vivo is primarily of interest to forensic scientists and has not yet been thoroughly researched. This preliminary study utilizes steady-state fluorescence spectroscopy to probe the changes in fluorescence properties of peripheral and menstrual blood up to 24-h post deposition. Peripheral and menstrual blood exhibited similar kinetic changes over time, assigned to the presence of the fluorophores: tryptophan, nicotinamide adenine dinucleotide (NADH), and flavins in both biological fluids. The biochemical mechanism of blood aging ex vivo is discussed.
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Affiliation(s)
- Alexis Weber
- Department of Chemistry, University at Albany, SUNY, 1400 Washington Avenue, Albany, NY 12222, USA
| | - Anna Wójtowicz
- Department of Chemistry, University at Albany, SUNY, 1400 Washington Avenue, Albany, NY 12222, USA; Laboratory for Forensic Chemistry, Department of Analytical Chemistry, Faculty of Chemistry, Jagiellonian University, 2 Gronostajowa St., 30-387 Kraków, Poland
| | - Igor K Lednev
- Department of Chemistry, University at Albany, SUNY, 1400 Washington Avenue, Albany, NY 12222, USA; Laboratory of Laser Molecular Imaging and Machine Learning (LM&ML), Tomsk State University, 36 Lenina Ave., Tomsk 634050, Russian Federation.
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Wójtowicz A, Weber A, Wietecha-Posłuszny R, Lednev IK. Probing menstrual bloodstain aging with fluorescence spectroscopy. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2021; 248:119172. [PMID: 33279406 DOI: 10.1016/j.saa.2020.119172] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/18/2020] [Revised: 10/21/2020] [Accepted: 10/30/2020] [Indexed: 06/12/2023]
Abstract
Menstrual blood (MB) is a common and important type of forensic evidence, especially in sexual assault cases. MB is composed of peripheral blood (PB), vaginal fluid, and endometrial cells of the uterine wall. In forensic investigations, the differentiation of MB and PB can determine whether the blood present is a result of tissue damage from an assault or a natural cause and thus help to reconstruct the event. Understanding how menstrual blood changes is necessary to develop a method for bloodstain aging. Fluorescence spectroscopy, a promising spectroscopic method for bloodstain analysis, was used to probe the biochemical changes that occur over time in menstrual bloodstains. It was found that steady-state fluorescence spectra underwent significant changes over first nine hours post deposition. The underlying mechanism of fluorescence changes was proposed to involve the kinetic transformation of three fluorophores: tryptophan, nicotinamide adenine dinucleotide and flavins.
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Affiliation(s)
- Anna Wójtowicz
- Department of Chemistry, University at Albany, SUNY, 1400 Washington Avenue, Albany, NY 12222, USA; Laboratory for Forensic Chemistry, Department of Analytical Chemistry, Faculty of Chemistry, Jagiellonian University, 2 Gronostajowa St., 30-387 Kraków, Poland
| | - Alexis Weber
- Department of Chemistry, University at Albany, SUNY, 1400 Washington Avenue, Albany, NY 12222, USA
| | - Renata Wietecha-Posłuszny
- Laboratory for Forensic Chemistry, Department of Analytical Chemistry, Faculty of Chemistry, Jagiellonian University, 2 Gronostajowa St., 30-387 Kraków, Poland
| | - Igor K Lednev
- Department of Chemistry, University at Albany, SUNY, 1400 Washington Avenue, Albany, NY 12222, USA.
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10
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Das T, Harshey A, Nigam K, Yadav VK, Srivastava A. Analytical approaches for bloodstain aging by vibrational spectroscopy: Current trends and future perspectives. Microchem J 2020. [DOI: 10.1016/j.microc.2020.105278] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
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12
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Menżyk A, Damin A, Martyna A, Alladio E, Vincenti M, Martra G, Zadora G. Toward a novel framework for bloodstains dating by Raman spectroscopy: How to avoid sample photodamage and subsampling errors. Talanta 2020; 209:120565. [DOI: 10.1016/j.talanta.2019.120565] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2019] [Revised: 11/07/2019] [Accepted: 11/12/2019] [Indexed: 01/22/2023]
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13
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Sauer L, Komanski CB, Vitale AS, Hansen ED, Bernstein PS. Fluorescence Lifetime Imaging Ophthalmoscopy (FLIO) in Eyes With Pigment Epithelial Detachments Due to Age-Related Macular Degeneration. Invest Ophthalmol Vis Sci 2019; 60:3054-3063. [PMID: 31348823 PMCID: PMC6660189 DOI: 10.1167/iovs.19-26835] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Purpose To investigate fluorescence lifetime imaging ophthalmoscopy (FLIO) in neovascular AMD and pigment epithelial detachments (PEDs). Methods A total of 46 eyes with PEDs (>350 μm) as well as age-matched healthy controls were included in this study. We found 28 eyes showed neovascular AMD (nvAMD), and 17 had nonneovascular (dry) AMD (dAMD). The Heidelberg Engineering FLIO excited fluorescence at 473 nm. Fluorescence decays were detected in two spectral channels (498–560 nm; 560–720 nm) to determine fluorescence lifetimes of endogenous fluorophores in their specific spectral emission ranges. Mean fluorescence lifetimes (τm) were investigated. Multimodal imaging was reviewed by two ophthalmologists who circumscribed and classified PEDs as either serous (n = 4), hemorrhagic (n = 4), fibrovascular (n = 16), drusenoid (n = 17), or mixed (n = 5). Blood samples from a healthy subject and a patient with PED were investigated in a quartz cuvette. Results Eyes with nvAMD show similar FLIO patterns to dAMD: ring-shaped prolongations of τm 3 to 6 mm from the fovea. Different PED-forms show characteristic τm, while serous and hemorrhagic PEDs exhibit shortened τm, drusenoid PEDs show prolonged τm, and τm in fibrovascular PEDs is variable. Areas corresponding to sub-/intraretinal fluid display shortened τm. Ex vivo studies of blood also show short τm. Conclusions The previously described dAMD-related FLIO pattern is also present in nvAMD. Short τm in serous, fibrovascular, and hemorrhagic PEDs as well as sub/intraretinal fluid may disrupt this pattern. FLIO appears to differentiate between PEDs, hemorrhage, and fluid. Additionally, ex vivo studies of human blood help to better interpret FLIO images.
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Affiliation(s)
- Lydia Sauer
- Department of Ophthalmology and Visual Sciences, John A. Moran Eye Center, University of Utah, Salt Lake City, Utah, United States
| | - Christopher B Komanski
- Department of Ophthalmology and Visual Sciences, John A. Moran Eye Center, University of Utah, Salt Lake City, Utah, United States
| | - Alexandra S Vitale
- Department of Ophthalmology and Visual Sciences, John A. Moran Eye Center, University of Utah, Salt Lake City, Utah, United States
| | - Eric D Hansen
- Department of Ophthalmology and Visual Sciences, John A. Moran Eye Center, University of Utah, Salt Lake City, Utah, United States
| | - Paul S Bernstein
- Department of Ophthalmology and Visual Sciences, John A. Moran Eye Center, University of Utah, Salt Lake City, Utah, United States
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14
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Nucleic acid carrier composed of a branched fatty acid lysine conjugate—Interaction studies with blood components. Colloids Surf B Biointerfaces 2019; 184:110547. [DOI: 10.1016/j.colsurfb.2019.110547] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2019] [Revised: 09/11/2019] [Accepted: 10/02/2019] [Indexed: 12/19/2022]
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16
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In the pursuit of the holy grail of forensic science – Spectroscopic studies on the estimation of time since deposition of bloodstains. Trends Analyt Chem 2018. [DOI: 10.1016/j.trac.2018.04.009] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
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17
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Estimation of the age of human bloodstains under the simulated indoor and outdoor crime scene conditions by ATR-FTIR spectroscopy. Sci Rep 2017; 7:13254. [PMID: 29038589 PMCID: PMC5643403 DOI: 10.1038/s41598-017-13725-1] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2017] [Accepted: 09/27/2017] [Indexed: 12/16/2022] Open
Abstract
Estimation of the age of human bloodstains is of great importance in forensic practices, but it is a challenging task because of the lack of a well-accepted, reliable, and established method. Here, the attenuated total reflection (ATR)-Fourier transform infrared (FTIR) technique combined with advanced chemometric methods was utilized to determine the age of indoor and outdoor bloodstains up to 107 days. The bloodstain storage conditions mimicked crime scene scenarios as closely as possible. Two partial least squares regression models—indoor and outdoor models with 7–85 days—exhibited good performance for external validation, with low values of predictive root mean squared error (5.83 and 4.77) and high R2 values (0.94 and 0.96) and residual predictive deviation (4.08 and 5.14), respectively. Two partial least squares–discriminant analysis classification models were built and demonstrated excellent distinction between fresh (age ≤1 d) and older (age >1 d) bloodstains, which is highly valuable for forensic investigations. These findings demonstrate that ATR-FTIR spectroscopy coupled with advanced chemometric methods can be employed as a rapid and non-destructive tool for age estimation of bloodstains in real-world forensic investigation.
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18
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Dysli C, Wolf S, Berezin MY, Sauer L, Hammer M, Zinkernagel MS. Fluorescence lifetime imaging ophthalmoscopy. Prog Retin Eye Res 2017; 60:120-143. [PMID: 28673870 PMCID: PMC7396320 DOI: 10.1016/j.preteyeres.2017.06.005] [Citation(s) in RCA: 126] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2017] [Revised: 06/19/2017] [Accepted: 06/29/2017] [Indexed: 12/17/2022]
Abstract
Imaging techniques based on retinal autofluorescence have found broad applications in ophthalmology because they are extremely sensitive and noninvasive. Conventional fundus autofluorescence imaging measures fluorescence intensity of endogenous retinal fluorophores. It mainly derives its signal from lipofuscin at the level of the retinal pigment epithelium. Fundus autofluorescence, however, can not only be characterized by the spatial distribution of the fluorescence intensity or emission spectrum, but also by a characteristic fluorescence lifetime function. The fluorescence lifetime is the average amount of time a fluorophore remains in the excited state following excitation. Fluorescence lifetime imaging ophthalmoscopy (FLIO) is an emerging imaging modality for in vivo measurement of lifetimes of endogenous retinal fluorophores. Recent reports in this field have contributed to our understanding of the pathophysiology of various macular and retinal diseases. Within this review, the basic concept of fluorescence lifetime imaging is provided. It includes technical background information and correlation with in vitro measurements of individual retinal metabolites. In a second part, clinical applications of fluorescence lifetime imaging and fluorescence lifetime features of selected retinal diseases such as Stargardt disease, age-related macular degeneration, choroideremia, central serous chorioretinopathy, macular holes, diabetic retinopathy, and retinal artery occlusion are discussed. Potential areas of use for fluorescence lifetime imaging ophthalmoscopy will be outlined at the end of this review.
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Affiliation(s)
- Chantal Dysli
- Department of Ophthalmology and Department of Clinical Research, Inselspital, Bern University Hospital, University of Bern, Switzerland
| | - Sebastian Wolf
- Department of Ophthalmology and Department of Clinical Research, Inselspital, Bern University Hospital, University of Bern, Switzerland
| | - Mikhail Y Berezin
- Department of Radiology, Washington University School of Medicine, St. Louis, Missouri, United States
| | - Lydia Sauer
- Department of Ophthalmology, University Hospital Jena, Jena, Germany
| | - Martin Hammer
- Department of Ophthalmology, University Hospital Jena, Jena, Germany
| | - Martin S Zinkernagel
- Department of Ophthalmology and Department of Clinical Research, Inselspital, Bern University Hospital, University of Bern, Switzerland.
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19
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Doty KC, McLaughlin G, Lednev IK. A Raman "spectroscopic clock" for bloodstain age determination: the first week after deposition. Anal Bioanal Chem 2016; 408:3993-4001. [PMID: 27007735 DOI: 10.1007/s00216-016-9486-z] [Citation(s) in RCA: 59] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2016] [Revised: 03/04/2016] [Accepted: 03/11/2016] [Indexed: 01/25/2023]
Abstract
Knowing the time since deposition (TSD) of an evidentiary bloodstain is highly desired in forensics, yet it can be extremely complicated to accurately determine in practice. Although there have been numerous attempts to solve this problem using a variety of different techniques, currently, no established, well-accepted method exists. Here, a Raman spectroscopic approach was developed for determining the age of bloodstains up to 1 week old. Raman spectroscopy, along with two-dimensional correlation spectroscopy (2D CoS) and statistical modeling, was used to analyze fresh bloodstains at ten time points under ambient conditions. The 2D CoS results indicate a high correlation between several Raman bands and the age of a bloodstain. A regression model was built to provide quantitative predictions of the TSD, with cross-validated root mean squared error and R (2) values of 0.13 and 0.97, respectively. It was determined that a "new" (1 h) bloodstain could be easily distinguished from older bloodstains, which is very important for forensic science in helping to establish the relevant association of multiple bloodstains. Additionally, all bloodstains were confirmatively identified as blood by comparing the experimentally measured spectra to multidimensional body fluid spectroscopic signatures of blood, saliva, semen, sweat, and vaginal fluid. These results demonstrate that Raman spectroscopy can be used as a nondestructive analytical tool for discriminating between bloodstains on the scale of hours to days. This approach shows promise for immediate practical use in the field to predict the TSD with a high degree of accuracy. Graphical Abstract Bloodstain aging over time illustrating naturally ocurring processes.
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Affiliation(s)
- Kyle C Doty
- Department of Chemistry, University at Albany, 1400 Washington Avenue, Albany, NY, 12222, USA
| | - Gregory McLaughlin
- Department of Chemistry, University at Albany, 1400 Washington Avenue, Albany, NY, 12222, USA
| | - Igor K Lednev
- Department of Chemistry, University at Albany, 1400 Washington Avenue, Albany, NY, 12222, USA.
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