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1.
Int J Legal Med ; 137(2): 545-549, 2023 Mar.
Article in English | MEDLINE | ID: mdl-36625885

ABSTRACT

Serious games (computer-based learning games) are increasingly used in medical education at various levels, as user access is independent of location and time and promotes non-linear learning. In legal medicine, interactive digital media are still scarce. The freely accessible online serious game "Adventure Legal Medicine" was developed as part of the "Hamburg Open Online University". The goal was to teach the basics of forensic casework in a point-and-click adventure setting consisting of five cases. During development, 40 medical students were asked to evaluate the game anonymously. The System Usability Scale (SUS) resulted in a mean score of 86.7 (SD 8.3), which corresponds to above-average usability. Further specific evaluations revealed a good to very good rating of the game with no differences in terms of gender (p = 0.214), first-year versus advanced students (p = 0.393) and students who never/rarely or sometimes/often played computer games (p = 0.780). Since there are only a few digital media so far that allow curricular integration into undergraduate teaching in legal medicine, this serious game represents a possibility to integrate digital media into both face-to-face teaching and distance learning and to use it as a supplement to the medical school's own teaching offer, encouraging users to actively engage with the subject.


Subject(s)
Education, Medical, Undergraduate , Education, Medical , Humans , Education, Medical, Undergraduate/methods , Internet , Learning , Education, Medical/methods , Forensic Medicine
2.
Int J Legal Med ; 133(6): 1751-1759, 2019 Nov.
Article in English | MEDLINE | ID: mdl-31511983

ABSTRACT

Post-mortem DNA degradation is still the real challenge of DNA-based identification in forensic practise. It is a complicated multifactorial process occurring as a result of the combination of several different environmental effects along with the crucial effect of the elapsed post-mortem interval (PMI). The main purpose of the present study is to evaluate the effect of ante- and post-mortem factors on dental DNA in real forensic cases. Ninety-five teeth extracted from 39 corpses, whose bodies were subject to 6 different post-mortem conditions, were used to evaluate dental DNA amount. In total, 179 DNA extracts isolated from the root of the teeth were examined after removing the crown and sectioning each root into apical and cervical portions. DNA concentration was measured using real-time polymerase chain reaction DNA quantitation kit (PowerQuant™ System/Promega). Our results indicate that the post-mortem interval (PMI) is the most important influential factor on dental DNA quantification (p < 0.001). However, in the actual data set, it was confounded with several ante- and post-mortem factors, rendering its actual net effect difficult. The time period of the first 10 days after death yielded the best DNA results from all analysed dental samples. Afterwards, a dramatic decrease in dental DNA was observed in the following time period. Teeth extracted from burnt and fresh corpses yielded the highest amount of DNA, while skeletonized exhumed corpses resulted in the lowest DNA amount. Indeed, dry and indoor conditions demonstrated better results than those in water, outdoors, or buried in the ground. On the other hand, ante-mortem factors including sex, age, tooth type, and tooth root portions did not reveal significant effect on dental DNA yield. We suggest that ante-mortem factors are considerably more subjected to individual variations. Post-mortem factors including PMI, post-mortem conditions, and the relevant surrounding environments have substantial influence on the dental DNA amount yielded.


Subject(s)
DNA/analysis , Postmortem Changes , Tooth Apex/chemistry , Tooth Root/chemistry , Adult , Aged , Aged, 80 and over , DNA Fingerprinting , Exhumation , Female , Fires , Forensic Dentistry , Humans , Male , Middle Aged , Real-Time Polymerase Chain Reaction , Young Adult
3.
Forensic Sci Int ; 302: 109926, 2019 Sep.
Article in English | MEDLINE | ID: mdl-31444040

ABSTRACT

Missing, ineligible or delayed reference data to establish conventional dental or DNA identification are common scenarios in forensic practice. Therefore, it is worthwhile to explore new avenues that facilitate human identification. Due to the recent remarkable evolution in the prosthetic dental restorations based on dental implants and the emergence of novel DNA technologies utilized to infer the biological profile, the identification process has become easier than ever before. We report on a characteristic case, which highlights the particular importance of dental implants and DNA approaches in the prospective investigations for human identification. The aim of this publication is to focus on the possibility of identifying the batch numbers, even if they were not engraved in dental implants, making antemortem dental records of dental implants more easily accessible to establish a comparative dental identification. In addition, the reported case presents the supplementary data yielded through estimating the epigenetic age using DNA methylation as well as the biogeographical origin using Y-Haplotype and mitochondrial DNA analyses. Our results demonstrate that expanded oral implant investigations that also include implants extraction and comprehensive microscopic measurements can lead to identifying their batch numbers despite the numerous number of implants systems manufactured and distributed worldwide. Data saved by dental implant manufacturers can be very supportive and represent additional reference data for dental identification, when antemortem dental records are still missing. Furthermore, DNA methylation and mitochondrial DNA analyses can support the progress of investigation.


Subject(s)
DNA Fingerprinting , Dental Implants , Microsatellite Repeats , Aged , Aged, 80 and over , CpG Islands/genetics , DNA Methylation , Dental Abutments , Forensic Dentistry , Forensic Genetics , Genotype , Humans , Male , Middle Aged , Radiography, Panoramic
4.
Int J Legal Med ; 133(5): 1567-1574, 2019 Sep.
Article in English | MEDLINE | ID: mdl-31020398

ABSTRACT

In cases of crimes involving blood, the perpetrators often attempt to remove the traces they have left behind. Setting fire to the crime scene, aside from cleaning measures, seems to achieve this goal and presents a major challenge for crime scene investigators. There is only very little published information available on the effect of fire and extreme heat on blood and the detection thereof. After exposure to high temperatures of or exceeding 1.000 °C, blood is deemed to be undetectable. This study exposed 11 different potentially crime-relevant objects using a standardized and controlled procedure to temperatures of 300 °C, 700 °C, and 1.000 °C documenting the influence of heat on bloodstains and the detection of blood. The results of the forensic collection of blood traces with and without liquid latex confirmed the advantage of using the latex method. Almost all objects showed a clear luminescence-caused visualization of traces of blood after removing the soot with a latex lift. There were also fewer false positive results than in tests not using latex.


Subject(s)
Blood Stains , Fires , Hot Temperature , Latex/chemistry , Luminescence , Luminescent Agents/chemistry , Luminol/chemistry , Blood Specimen Collection/methods , Crime , Forensic Sciences , Humans , Temperature
5.
J Forensic Leg Med ; 54: 76-81, 2018 Feb.
Article in English | MEDLINE | ID: mdl-29328966

ABSTRACT

Each forensic case is characterized by its own uniqueness. Deficient forensic cases require additional sources of human identifiers to assure the identity. We report on two different cases illustrating the role of teeth in answering challenging forensic questions. The first case involves identification of an adipocere male found in a car submersed in water for approximately 2 years. The second scenario, which involves paternity DNA testing of an exhumed body, was performed approximately 2.8 years post-mortem. The difficulty in anticipating the degradation of the DNA is one of the main obstacles. DNA profiling of dental tissues, DNA quantification by using real-time PCR (PowerQuant™ System/Promega) and a histological dental examination have been performed to address the encountered impediments of adverse post-mortem changes. Our results demonstrate that despite the adverse environmental conditions, a successful STR profile of DNA isolated from the root of teeth can be generated with respect to tooth type and apportion. We conclude that cementocytes are a fruitful source of DNA. Cementum resists DNA degradation in comparison to other tissues with respect to the intra- and inter-individual variation of histological and anatomical structures.


Subject(s)
DNA Fingerprinting/methods , DNA/isolation & purification , Dental Cementum/chemistry , Dental Cementum/diagnostic imaging , Exhumation , Humans , Male , Microsatellite Repeats , Multiplex Polymerase Chain Reaction , Paternity , Postmortem Changes , Real-Time Polymerase Chain Reaction , X-Ray Microtomography
7.
Arch Kriminol ; 233(5-6): 203-9, 2014.
Article in German | MEDLINE | ID: mdl-25004622

ABSTRACT

The article reports on the exhumation and subsequent DNA analysis of the skeletal remains of an unknown male newborn from 1988. Molecular biological methods confirmed the maternity of a woman who was already convicted of infanticide. Since homicide could not be clearly proven and manslaughter becomes barred by the statute of limitation after 20 years, the woman cannot be held accountable for the alleged killing of her first child.


Subject(s)
Asphyxia Neonatorum/pathology , DNA Fingerprinting , Exhumation/legislation & jurisprudence , Forensic Anthropology/legislation & jurisprudence , Infanticide/legislation & jurisprudence , Postmortem Changes , Humans , Infant, Newborn , Male , Paternity
8.
Arch Kriminol ; 234(5-6): 183-92, 2014.
Article in German | MEDLINE | ID: mdl-26548020

ABSTRACT

Myiasis is known as the infestation of living organisms with maggots. It is often caused by (self-) neglect. Eight cases of myiasis have been examined at the Institute of Legal Medicine in Hamburg between 2002 and 2014. It is important that the medical examiner compares the maggots' stage of development with the alleged time of death. Especially in cases of home care, myiasis and neglect are suspicious and deserve special attention.


Subject(s)
Elder Abuse/classification , Elder Abuse/diagnosis , Forensic Medicine/methods , Myiasis/diagnosis , Aged , Aged, 80 and over , Diagnosis, Differential , Elder Abuse/legislation & jurisprudence , Female , Germany , Humans , Male
9.
Org Lett ; 7(6): 1063-6, 2005 Mar 17.
Article in English | MEDLINE | ID: mdl-15760139

ABSTRACT

[structure: see text] A strategy for the synthesis of ajudazol A, an unusual, pharmacologically active metabolite from myxobacteria, based on the Stille cross-coupling of a 2-stannyl-oxazole with a vinyl iodide unit is described; the vinyl halide unit containing a (Z,Z)-diene was prepared in one pot by the double acetylene carbocupration of a functionalized alkyl cuprate followed by trapping with 2,3-dibromopropene.


Subject(s)
Acetylene/chemistry , Coumarins/chemical synthesis , Coumarins/chemistry , Molecular Structure , Myxococcales/chemistry , Stereoisomerism
11.
J Org Chem ; 68(6): 2420-5, 2003 Mar 21.
Article in English | MEDLINE | ID: mdl-12636411

ABSTRACT

The intramolecular and intermolecular kinetic isotope effects (KIE) have been determined for the nitrosoarene ene reaction with deuterium-stereolabeled 2,3-dimethyl-2-butenes (TME). trans-TME-d(6) (k(H)/k(D) = 3.0) and gem-TME-d(6) (k(H)/k(D) = 4.0) show large intramolecular primary isotope effects. In contrast, the intramolecular competition in cis-TME-d(6) (k(H)/k(D) = 1.5) and the intermolecular competition for the TME-d(0)/TME-d(12) pair (k(H)/k(D) = 1.98) show considerably smaller, but mechanistically significant kinetic isotope effects. The latter fact is rationalized in terms of reversible formation of a three-membered-ring intermediate, namely the aziridine N-oxide, or a similar unsymmetrical, polarized diradical in the first step of the reaction. Such reversibility has also been implied earlier for triazolinedione (TAD) and singlet oxygen ((1)O(2)) with deuterium-stereolabeled 2-butenes, but of the three enophiles, ArNO is the most sensitive toward reversibility, which is due to its moderate reactivity and its high steric demand.

12.
J Org Chem ; 67(25): 8758-63, 2002 Dec 13.
Article in English | MEDLINE | ID: mdl-12467386

ABSTRACT

The regioselectivity for the intrazeolite photooxygenation of several trisubstituted alkenes with geminal dimethyl groups was examined. The length of the alkyl chain at the lone position was varied, and as end groups, the phenyl or the cyclohexyl functionalities were chosen. The general trend for all alkenes is a significant increase of the reactivity at the twin position compared to the photooxygenation in solution. For the cyclohexyl-substituted alkenes, it was found that the regioselectivity is nearly independent of the alkyl chain length. However, for the phenyl-substituted alkenes, the ene reactivity of the allylic methylene hydrogen atoms at the lone position and the twix/twin regioselectivity depend significantly on the distance of the phenyl group from the double bond. These trends are discussed in terms of cation-pi interactions and conformational effects. Intramolecular and intermolecular isotope effects in the intrazeolite photooxygenation of deuterium-labeled alkenes suggest that a perepoxide-type intermediate is formed in the rate-determining step. Type I photooxygenation that involves reaction of the radical cations of the alkenes with superoxide ion are unlikely.

13.
J Am Chem Soc ; 124(48): 14403-9, 2002 Dec 04.
Article in English | MEDLINE | ID: mdl-12452715

ABSTRACT

The ene reaction of singlet oxygen ((1)O(2)), triazolinedione (TAD), and nitrosoarene, specifically 4-nitronitrosobenzene (ArNO), with the tetrasubstituted 1,3-allylically strained, chiral allylic alcohol 3,4-dimethylpent-3-en-2-ol (2) leads to the threo-configured ene products in high diastereoselectivity, a consequence of the hydroxy-group directivity. Hydrogen bonding favors formation of the threo-configured encounter complex threo-EC in the early stage of ene reaction. For the analogous twix deuterium-labeled allylic alcohol Z-2-d(3), a hitherto unrecognized dichotomy between (1)O(2) and the ArNO and TAD enophiles is disclosed in the regioselectivity of the tetrasubstituted alcohol: Whereas for ArNO and TAD, hydrogen bonding with the allylic hydroxy group dictates the regioselectivity (twix selectivity), for (1)O(2), the cis effect dominates (twin/trix selectivity). From the interdependence between the twix/twin regioselectivity and the threo/erythro diastereoselectivity, it has been recognized that the enophile also attacks the allylic alcohol from the erythro pi face without assistance by hydrogen bonding with the allylic hydroxy functionality.

14.
J Org Chem ; 67(24): 8395-9, 2002 Nov 29.
Article in English | MEDLINE | ID: mdl-12444616

ABSTRACT

For the ene reaction of 4-nitronitrosobenzene (ArNO) with a variety of primary and secondary lone alkyl-substituted substrates, the twix/twin regioselectivity is constant at about 85:15. In contrast, for the lone tert-butyl group and for lone aryl substituents, the twix regioisomer is obtained exclusively. These regioselectivities have been rationalized in terms of steric interactions and coordination between the enophile and the substrates in the transition states of the first reaction step.

15.
J Am Chem Soc ; 124(44): 12938-9, 2002 Nov 06.
Article in English | MEDLINE | ID: mdl-12405807

ABSTRACT

The ene reaction of 4-nitronitrosobenzene (ArNO), N-phenyl-1,2,4-triazoline-3,5-dione (PTAD), and singlet oxygen (1O2) with the optically active tiglic-acid derivatives of Oppolzer's bornane-derived sultam affords the respective ene products regioselectively in excellent diastereoselectivity (de up to 99%) and in good yield (55-90%). The enophiles ArNO and PTAD give with the methyl-substituted substrate exclusively the like-configured ene adduct, while 1O2 leads to an 83:17 diastereomeric mixture. With the sterically more demanding isopropyl-substituted derivative even the smallest enophile 1O2 forms exclusively the like diastereomer. The high diastereoselectivity is rationalized in terms of the proper conformational alignment of the substrate and a preferred enophilic attack from the C(beta)-re face of the double bond. This concept offers an efficient synthetic route to enantiomerically pure nitrogen- and oxygen-functionalized acrylic acid derivatives.


Subject(s)
Acrylates/chemical synthesis , Alkenes/chemistry , Amino Acids/chemical synthesis , Camphanes/chemistry , Nitroso Compounds/chemistry , Singlet Oxygen/chemistry , Triazoles/chemistry , Acrylates/chemistry , Stereoisomerism
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