ORCID Profile
0000-0001-6180-7666
Current Organisations
Universitätsklinikum Münster
,
Harbin Institute of Technology
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Publisher: Springer Science and Business Media LLC
Date: 18-01-2014
DOI: 10.1007/S12024-013-9515-6
Abstract: Despite their wide use, the limits of presumptive tests can be poorly understood. The aim of this study was to investigate the specificity and sensitivity of conventional, as well as innovative, presumptive tests for blood, semen and saliva. We investigated Kastle-Meyer (KM) and leucomalachite green (LMG) tests for blood with regard to their sensitivity and specificity in the presence of oxidizing (hypochlorite) and anti-oxidizing (ascorbic acid) agents. The suitability and specificity of the red starch paper (RSP) test for saliva was assessed. Finally, the inhibitory effect of detergent on the acid phosphatase (AP) test for semen was investigated along with possible cross reactions to tea stains. Our results confirm previous findings of higher sensitivity and specificity of the KM test compared to LMG test for blood. Contrary to previous studies, no statistically significant difference was observed in the sensitivity of the tests between dry and wet stains. The novel RSP test was found to successfully detect saliva. We demonstrated that acid phosphatase (AP) testing for semen is possible on used RSP. A common multipurpose detergent had an inhibitory effect on AP tests. False positive results were obtained from tea stains. Testing different sorts of tea (black, green and herbal teas) revealed that only Camellia varieties produce positive result with the AP test, due to AP being present in the plants. From our results we conclude that specific knowledge of each test, including substances that may affect the test outcome, is imperative to ensure correct interpretation of presumptive test results.
Publisher: Wiley
Date: 26-07-2021
Abstract: Metasurfaces have shown their unprecedented ability in wavefront shaping and triggered various applications with state‐of‐the‐art performances, e.g., color nanoprinting and metaholograms. Recently, these two functions have been combined into a single metasurface to further expand its capabilities. Despite the progress, the current dual‐mode metasurfaces are mostly static and strongly hinder their practical applications. Herein, the realization of dynamic bifunctional metasurfaces is reported. Five metaholograms at two different wavelengths are multiplexed with structural colors by controlling the spectral and phase response of metasurface. Owing to the destructive interference and the resonance on external environment, the light diffraction at particular wavelengths can be switched between “ON” and “OFF” states, or remain unchanged with the change of surrounding refractive index. Consequently, the encoded metaholograms are selectively turned on and off, making the overall holographic image dynamically switchable. This concept paves a solid step toward practical applications of all‐dielectric metasurfaces.
Publisher: Elsevier BV
Date: 06-2015
DOI: 10.1016/J.FORSCIINT.2015.03.014
Abstract: Current histological investigation of vaginal swabs after alleged sexual assault includes the scoring of spermatozoa (0, + to ++++) and the recording of visible tails. It is a method that is universally employed. Despite this method being used for 40 years, there has never been a study investigating its suitability for forensic science. Here, we investigate the reproducibility and subjectivity of sperm scoring among different investigators. Dilutions of seminal fluid were randomly distributed onto 20 slides, stained with haematoxylin/eosin and assessed by 37 investigators, over 2 years. Slides were assessed for levels of spermatozoa and the presence of tails. Each slide was scored by a minimum of 25 investigators. On no slide was there a consensus between all scores. Standard deviation remained below 1, but relative standard deviation (RSD) ranged from 6 to 105% in a positive correlation as the average score decreased. Spermatozoa were not observed 56 times (9.6%) and 27 investigators (73%) did not observe spermatozoa on at least one slide. Spermatozoa with tails were observed on every slide by at least 10 examiners, but as the average score of the slide decreased, so did the observation of tails. The current sperm scoring method is highly subjective with a particularly high %RSD in slides with low overall sperm counts. Moreover, the recording of tails does not add value to the current technique of sperm scoring. Further research might improve the objectivity of sperm scoring and the reliability of recording of tails.
Publisher: Springer Science and Business Media LLC
Date: 10-11-2016
DOI: 10.1007/S00414-016-1461-X
Abstract: Sexual assault s les are some of the most common s les encountered in forensic analysis. These s les can require a significant time investment due to differential extraction processes. We report on the first record of successful direct lification of semen for STR analysis. Neat seminal fluid, dilutions ranging from 1:5 to 1:160 and GEDNAP s les were successfully lified using a direct method. A mild differential isolation technique to enrich spermatozoa was developed and successfully implemented to separate and directly lify a mixture of semen and female epithelial cells. Aliquots of s les subjected to the differential isolation protocol were stained with Haemotoxylin and Eosin for sperm scoring. S les stained after PCR showed a complete lack of intact spermatozoa demonstrating that the cells are lysed during the PCR process. This paper demonstrates the potential to incorporate direct PCR in cases of sexual assault to more rapidly obtain results and achieve a higher sensitivity.
Location: United Kingdom of Great Britain and Northern Ireland
No related grants have been discovered for Marielle Vennemann.