Separation of sperm and epithelial cells based on fluorescence-activated cell sorting

The detection and separation of spermatozoa is crucial in the forensic investigation of alleged sexual assault cases. Differential lysis and microscopy-based techniques are conventional methods for the isolation of spermatozoa, though are time-consuming and frequently fail with samples containing an unfavourable sperm/epithelial cell ratio. Successful separation by means of fluorescence-activated cell sorting (FACS) has previously been reported, yet little efforts have been dedicated towards the further improvement or routine implementation of this technique. With this ongoing research, a methodology is being developed to sort sperm from epithelial cells by combining the Sperm Hy-Liter™ staining kit and FACS. Sorted sperm cells are then subjected to a direct lysis and low volume PCR (LV-PCR) protocol. Preliminary results demonstrate the successful separation of both cell types at a sperm/epithelial cell ratio of up to 1:500. The direct lysis and LV-PCR protocol allows to produce full haploid profiles from single sperm cells and mostly full diploid profiles from 10 spermatozoa. These data suggest that the proposed methods are potentially viable for forensic casework, yet additional testing is required for validation purposes.     

How many DNA analyses are performed on adult sexual assault victims in Milan (Italy): A ten-year review

The aim of this study is to evaluate the actual use of serological/DNA analyses in the investigations carried out on adult sexual violence victims in Italy during the years 2006–2015.The victims were assisted in the largest Italian rape center, in Milan (Soccorso Violenza Sessuale e Domestica – SVSeD - Service for Sexual and Domestic Violence).The total number of sexual violence victims examined during the years 2006–2015 (adults and minors) was 3521, in 1697 of cases, biological evidence had been collected, while the number of adult victims (>18 y.o.) examined was 2300, in 1211 of cases biological evidence had been collected.Biological evidence was collected from the victims’ bodies using two swabs in five anogenital areas (labia maiora, labia minora, perineum, perianal and anal/rectum regions) and two swabs in all other skin areas suggested by the victims as areas of possible contact (double swab technique). Clothes were also collected on a case by case basis for the search of biological stains. Despite the proper collection, handling and chain of custody for all the swabs/items collected, serological/DNA analyses were requested in 86 cases out of 1211 only (710%). This percentage dropped to 190% when considering adolescent victims (13–19 y.o.).The reason why Italian Magistrates make little use of the powerful tool of DNA analyses in sexual assault cases, still remains unclear. Legal and procedural aspects are therefore also discussed.     

Autonomous weapon system: Law of armed conflict (LOAC) and other legal challenges

The legality of autonomous weapon systems (AWS) under international law is a swiftly growing issue of importance as technology advances and machines acquire the capacity to operate without human control. This paper argues that the existing laws are ineffective and that a different set of laws are needed. This paper examines several issues that are critical for the development and use of AWS in warfare. It argues that a preemptive ban on AWS is irrelevant at this point and urges the appropriate authorities to develop a modern legal framework that is tailored to embrace these state-of-the-art weapons as the Law of Armed Conflict (LOAC) develops. First, this paper explores the myriad of laws designed to govern the potential future development and deployment of artificial intelligence and AWS in the context of International Humanitarian Law or LAOC. Second, the paper argues that it will be challenging for AWS to fulfill the requirements laid out under the International Committee of the Red Cross and LOAC for the rules of humanity, military necessity, distinction, proportionality and precaution, especially as it is related to noncombatants. Third, the paper discusses command responsibility and argues that states should establish accountability for wrongful acts committed by the AWS. Finally, this paper contends that there is an urgent need for a new legal framework to regulate these AWS and presents different solutions for the legal framework of AWS.     

Y-STRs in forensic medicine: DNA analysis in semen samples of azoospermic individuals

ABSTRACT: The incidence of rape has increased, especially in metropolitan areas, such as the city of São Paulo. In Brazil, studies about it have shown that the majority of this type of crime is committed by the relatives and persons close to the victim. This has made the crime more difficult to be denounced, as only 10% of the cases are reported to competent police authorities. Usually, cytological exams are carried out in sex crime investigations. The difficulty in showing the presence of spermatozoa is frequent, but it does not exclude the presence of male DNA. The absence of spermatozoa in material collected from rape victims can be due to several factors, including the fact that the agressor suffers from azoospermia. This condition can be the result of a successful vasectomy. As the majority of DNA in the ejaculation sample is from spermatozoa, there is much less DNA to be analyzed. This study presents the application of Y‐STRs (DYS19, DYS389I, DYS389II, DYS390, DYS391, DYS392, and DYS393) in DNA analysis of sperm samples from 105 vasectomized men. The study demonstrated a great variation in DNA concentration. DNA extraction and amplification was possible in all sperm samples even in the absence of spermatozoa. The same profile was observed, for each individual, from DNA extracted from blood, pre‐ and postvasectomy semen samples. The use of markers specific for Y chromosome in sex crime cases, especially in the absence of spermatozoa, is very important, mainly because in most situations there is a small quantity of the agressor's DNA in the medium and a large quantity of the victim's DNA.     

Co-occurring serious mental illnesses and substance use disorders as predictors of assaultive infraction charges among adult male jail inmates

This study used self-report data from 4642 adult male jail inmates to test the hypothesis that inmates with co-occurring serious mental illnesses (SMIs) and substance use disorders (SUDs) (i.e. co-occurring disorders) would report having been officially charged for assaulting staff or inmates more often than inmates without co-occurring disorders. Negative binomial regression indicated that relative to inmates with neither SMI nor SUDs, assault charges were most likely to be reported by inmates with co-occurring SMI and substance abuse, co-occurring SMI and substance dependence, and only substance abuse, respectively (ps ≤ .01). Having been charged with assault was also strongly associated with assault victimization before and while incarcerated (ps ≤ .05). This article concludes with recommendations for jail policies and future research.     

Single source DNA profile recovery from single cells isolated from skin and fabric from touch DNA mixtures in mock physical assaults

The ability to obtain DNA profiles from trace biological evidence is routinely demonstrated with so-called ‘touch DNA evidence’, which is generally perceived to be the result of DNA obtained from shed skin cells transferred from a donor's hands to an object or person during direct physical contact. Current methods for the recovery of trace DNA employ swabs or adhesive tape to sample an area of interest. While of practical utility, such ‘blind-swabbing’ approaches will necessarily co-sample cellular material from the different individuals whose cells are present on the item, even though the individuals' cells are principally located in topographically dispersed, but distinct, locations on the item. Thus the act of swabbing itself artifactually creates some of the DNA mixtures encountered in touch DNA samples. In some instances involving transient contact between an assailant and victim, the victim's DNA may be found in such significant excess as to preclude the detection and typing of the perpetrator's DNA. In order to circumvent the challenges with standard recovery and analysis methods for touch DNA evidence, we reported previously the development of a ‘smart analysis’ single cell recovery and DNA analysis method that results in enhanced genetic analysis of touch DNA evidence. Here we use the smart single cell analysis method to recover probative single source profiles from individual and agglomerated cells from various touched objects and clothing items belonging to known donors. We then use the same approach for the detection of single source male donor DNA in simulated physical contact/assault mixture samples (i.e. male ‘assailant’ grabbing the wrist, neck or clothing from the female ‘victim’, or being in transient contact with bedding from the ‘victim’). DNA profiles attributable to the male or female known donors were obtained from 31% and 35% of the single and agglomerated bio-particles (putative cells) tested. The known male donor ‘assailant’ DNA profile was identified in the cell sampling from every mixture type tested. The results of this work demonstrate the efficacy of an alternative strategy to recover single source perpetrator DNA profiles in physical contact/assault cases involving trace perpetrator/victim cellular admixtures.     

Differentiating sexual violence: A comparison of sexual homicide and rape

Abstract

The present study sought to identify consistent patterns in the actions of sexually violent offenders to determine whether sexual homicide and rape reflect different behavioral emphasis of a single thematic model of sexual assault. Crime scene behaviors of 74 (37 sexual homicides and 37 rapes) solved cases of sexual assaults were compared, and results of a multi-dimensional analysis revealed three thematic styles of interacting with the victim during a sexual assault (Exploit, Control, and Violent). Further analysis indicated that offender–victim interactions in sexual homicide and rape are predominantly distinguished by the degree of violence, such that behaviors associated with each type of offense were found to occur in two discrete areas along a single continuum. Findings are discussed in terms of producing a general framework for understanding sexual violent interactions.     

The impact of increasing vs. decreasing harassing behaviours on perceptions of hypothetical instances of repeated sexual harassment

ABSTRACT

Sexual harassment is a traditionally underreported crime. One factor that might affect perceptions and willingness to report harassment is its occurrence over time: harassing behaviours that gradually increase or decrease in severity over time might impact its perception. In the present research, 177 female participants read a series of daily scenarios about increasing, decreasing, or steady harassment, and completed measures regarding their perceptions of and willingness to report it. Participants displayed increases and decreases in negative reactions as harassment increased and decreased, respectively, suggesting that each instance of sexual harassment is interpreted independently of earlier harassing behaviours, and that early, strongly harassing behaviours have little impact on how subsequent instances of harassment are perceived. This explanation is supported by the similar ratings in the midpoint (day 4) of the scenario series, regardless of whether harassment was increasing or decreasing.     

The efficiency of Y-chromosome markers in forensic trace analysis and their inclusion in the Austrian National DNA Database

Y-STR markers are a valuable tool in the analysis of biological traces in which a mixture of male and female trace material is to be expected. It is possible to generate a Y-chromosome DNA profile, even if all the prior sperm tests are negative and no sign of any male component is found in amelogenin. In 38 of a total of 239 sexual offences a perpetrator trace was identified solely using Y-STR analysis. Based on these findings, the Austrian National DNA Database was expanded to include Y-STRs in 2012 with the primary objective to identify serial sexual offences.