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Biomedical subjects

D Sweet

Publications and source records attributed to D Sweet.

At least 19 recordsLinked to original sources
PubMed2002

Determination of the sensitivity and specificity of sibship calculations using AmpF lSTR Profiler Plus.

In circumstances where a known DNA reference sample from the deceased's belongings or biological parents is not available, more complex kinship analyses are possible. The purpose of the work reported here is to determine the sensitivity and specificity of the sibship analysis utilising multiple STR loci. Using all nine Profiler Plus loci, likelihood ratios for biologically-related siblings ranged from slightly less than 1 to over 45,000. When allelic dropout was mimicked, likelihood ratios ranged from less than 1 to over 1,000. Thus, the results of this study have a direct application to forensic laboratories faced with identifications involving sibling comparisons.

British Columbia↗
PubMed2002

The emotional and psychological impact of mass casualty incidents on forensic odontologists.

Motivated by the findings of a previous research project, 38 forensic odontologists with known occupational experience of mass casualty incidents completed a questionnaire designed to elicit both quantitative and qualitative data. The questionnaire sought to provide an insight into the psychological and emotional impact of conducting work of this nature. Two psychometric scales were included in the questionnaire, The Positive and Negative Affect scale (PANAS) and the Impact of Events Scale (IOE). In addition, a number of open-ended questions relating to the personal experiences of the respondent during the mass casualty incident were also included. Quantitative findings indicate that on the whole mass casualty incidents resulted in a positive experience for the respondents, although over a third reported being distressed, upset or irritable at some time during the event. Sense of achievement and camaraderie were among the qualitative themes elicited that help explain the positive reactions. Working conditions, politics and the ictims were cited as sources of negativity.

Canada↗
PubMed2001

Blowout bifurcations and the onset of magnetic activity in turbulent dynamos.

The transition to magnetic-field self-generation in a turbulent, electrically conducting fluid is shown to exhibit intermittent bursting characterized by distinct scaling laws. This behavior is predicted on the basis of prior analysis of a type of bifurcation (called a blowout bifurcation) occurring in chaotic systems with an invariant phase space submanifold. The predicted scalings are shown to be consistent with numerical solutions of the governing magnetohydrodynamic equations, and implications for recently implemented experimental programs are discussed.

Journal Article↗
PubMed2001

A look at forensic dentistry--Part 2: teeth as weapons of violence--identification of bitemark perpetrators.

Teeth are often used as weapons when one person attacks another or when a victim tries to ward off an assailant. It is relatively simple to record the evidence from the injury and the teeth for comparison of the shapes, sizes and pattern that are present. However, this comparative analysis is often very difficult, especially since human skin is curved, elastic, distortable and undergoing oedema. In many cases, though, conclusions can be reached about any role a suspect may have played in a crime. Additionally, traces of saliva deposited during biting can be recovered to acquire DNA evidence and this can be analyzed to determine who contributed this biological evidence. If dentists are aware of the various methods to collect and preserve bitemark evidence from victims and suspects it may be possible for them to assist the justice system to identify and prosecute violent offenders. This paper reviews the recognition and recovery of this evidence and provides insight into modern methods used to investigate bitemark evidence from heinous crimes.

Bites, Human↗
PubMed2001

A look at forensic dentistry--Part 1: The role of teeth in the determination of human identity.

Forensic dentistry can be defined in many ways. One of the more elegant definitions is simply that forensic dentistry represents the overlap between the dental and the legal professions. This two-part series presents the field of forensic dentistry by outlining two of the major aspects of the profession: human identification and bite marks. This first paper examines the use of the human dentition and surrounding structures to enable the identification of found human remains. Conventional and novel techniques are presented.

DNA Fingerprinting↗
PubMed2001

Stagger-and-step method: detecting and computing chaotic saddles in higher dimensions.

Chaotic transients occur in many experiments including those in fluids, in simulations of the plane Couette flow, and in coupled map lattices. These transients are caused by the presence of chaotic saddles, and they are a common phenomenon in higher dimensional dynamical systems. For many physical systems, chaotic saddles have a big impact on laboratory measurements, but there has been no way to observe these chaotic saddles directly. We present the first general method to locate and visualize chaotic saddles in higher dimensions.

Journal Article↗
PubMed2001

The design and assessment of mock mass disasters for dental personnel.

Mass disasters represent a significant challenge for dental personnel who are frequently called upon to provide identifications. Recently-published materials have highlighted the need to prepare such groups for the disaster challenge and to report inadequacies in existing preparation methods with an emphasis on team integration, organization, and the psychological and emotional effects of such work. Many studies have retrospectively reported errors that have been made in disaster situations, but few have addressed the issues proactively. In an effort to provide a prepared team of dental members, a mock disaster exercise (Operation: DENT-ID) is conducted annually in Vancouver, Canada. The present study analyzes the effectiveness of this exercise in relation to team organization, assessment of preparedness, and the emotional and psychological issues. An index of preparedness is developed and described. This index, in the form of a questionnaire, can be given to participants in mock disasters to assess the effectiveness of such exercises. While the focus of this paper is on the assessment of dental personnel, the indices and methods used can be applied to any group working within the disaster team. Results indicate that the increase in preparedness as a result of the exercise was highly significant.

Adaptation, Psychological↗
PubMed2001

Why a dentist for identification?

Identification of humans using the unique features of the teeth and jaws has been used since Roman times. Throughout history, various stories have been recorded in which a person's unusual smile, crowded or fractured teeth, or a single darkened tooth have been used to identify a corpse to the exclusion of all other people. Today, dentists are respected widely as a source of valuable data that can be used to answer questions that arise during a death investigation, and forensic dentists can use these data to provide significant conclusions that can initiate, extend, and substantiate the work of coroners, medical examiners, and detectives. By examining the dental traits and characteristics of one or many bodies, it is possible for the odontologist to provide the corpse with its identity and satisfy a basic societal need.

Adult↗
PubMed2001

Adherence of forensic odontologists to the ABFO bite mark guidelines for suspect evidence collection.

Boards and associations within forensic science have long been accepted as vehicles for the development and dissemination of protocols and recommendations for practice. Recent controversies surrounding bite mark analyses have brought the methods and practices of forensic dentists to the attention of both the courts and the media. In the mid-eighties the American Board of Forensic Odontology developed guidelines for bite mark analysis in response to unfavorable commentaries on the discipline by legal observers. The purpose of this study is to examine the adherence of board certified and noncertified forensic dentists to the guidelines for collection of evidence from bite mark suspects. A questionnaire was employed during an American Academy of Forensic Sciences meeting. Results showed that, in general, when the odontologists collected evidence they did adhere to the guidelines, although collection of salivary samples was not common. Of concern is the large number of odontologists who do not collect their own evidence from suspects. Police officers or other individuals often perform this task and therefore the guidelines must be disseminated to these groups to ensure that the maximum yield is obtained from bite mark evidence. A review of the materials used to collect evidence is also included with details of applications in forensic science.

Bites, Human↗
PubMed2001

Digital bite mark overlays--an analysis of effectiveness.

U.S. courts have stated that witnesses must be able to identify published works that define operational parameters of any tests or procedures that form the basis of scientific conclusions. Such works do not exist within the field of bite mark analysis. As the most commonly employed analytical technique in bite injury assessment. this study defines quantifiable variables for transparent digital overlays. A series of ten simulated, postmortem bites were created on pigskin and, with accompanying overlays, assembled into cases. Using two separate studies with four examiner groups, the study defined values of intra- and inter-examiner reliability, accuracy. sensitivity, specificity, and error rates for transparent overlays. Methods and statistical treatments from medical decision-making and diagnostic test evaluation were employed. Forced decision models and receiver operating characteristic analyses were utilized. Sensitivity and specificity values are described. and the results are consistent with other dental diagnostic systems. It was concluded that the weak inter-examiner reliability values explain the divergence of odontologists' opinions regarding bite mark identifications often stated in court. The effect of training and experience of the examiners was found to have little effect on the effective use of overlays within this study. The authors conclude that further research is required so that the results of the current study can be placed into context, but this represents a significant first step in establishing the scientific basis for this aspect of forensic dentistry.

Animals↗
PubMed2000

Anatomical location of bitemarks and associated findings in 101 cases from the United States.

The purpose of this paper is to update and confirm previous studies that examined the anatomical location of human bitemarks. This information is useful to forensic odontologists and pathologists, physicians, and coroners who must be familiar with the most likely locations of bitemarks. The data are also useful for those involved in bitemark research. Using the legal database "Lexis," 101 bitemark cases were identified from the United States Courts of Appeal. Cases were included in the study if they provided details concerning the bitemark, such as anatomical location, number of injuries, and information concerning the victim. Information on 148 bites was collated. These data are presented in tabular and graphical form to allow comparisons between males and females, victims and perpetrators, adults and children, and the crime types associated with human bites.

Adolescent↗
PubMed1999

Saliva from cheese bite yields DNA profile of burglar: a case report.

Physical evidence in the form of a high quality bite mark was discovered on a piece of yellow cheese found at the scene of a crime. The cheese had been frozen by police for 10 days after recovery and before submission to the laboratory for testing. The double swab technique was used to collect DNA samples. A sample of the suspect's blood was obtained. Using PCR-based DNA typing at ten STR loci, (Profiler Plus, Perkin Elmer-Applied Biosystems) it was determined that the DNA from the cheese originated from the suspect. This case illustrates the importance of a) always considering human bite marks as both physical and biological evidence, and b) attempting DNA recovery in any case in which minute traces of saliva may be present, even in situations involving bacteria-rich foods.

Cheese↗
PubMed1999

Microbial fusion.

Explore the source record for details and available documents.

Bacterial Adhesion↗
PubMed1999

Potential for fraudulent use of digital radiography.

BACKGROUND: Digital radiographic images can be manipulated using personal computers. To test the potential for fraudulent use, the authors altered a series of dental radiographs, printed them to simulate duplicated films and submitted them for authorization of proposed treatment. MATERIALS AND METHODS: The authors obtained periapical radiographs of teeth that contained small restorations or were unrestored from the files of three dental patients at a private dental practice. The authors used a flatbed scanner to digitize and import the radiographs into a computer. Then they added dental caries, large restorations, fractures and periapical pathosis to the radiographs. The authors proposed to the insurance companies that the teeth in question be restored using expensive treatment, such as root-canal therapy and full-coverage crowns. RESULTS: In each case, the insurance companies authorized the proposed treatment based on the appearance of the teeth on the radiographs. The altered images illustrated an apparent need for dental treatment that was not required and that could have led to payment for treatment that was not actually performed. CONCLUSIONS: This study illustrates the potential for the fraudulent use of manipulated digital radiographic images. CLINICAL IMPLICATIONS: Dentistry should be aware of the implications of the potential for such abuse and should develop measures both to prevent it from occurring and to facilitate its detection.

Computer Security↗
PubMed1999

Identification of a skeleton using DNA from teeth and a PAP smear.

Identification of unknown living or deceased persons using dental treatment records is an established forensic technique. However, some cases remain unidentified, especially when antemortem dental records are not available for comparison to postmortem dental records. Cytological smears have been previously reported to be potential sources of DNA reference samples which can be compared to DNA recovered from found human remains. The case described here involves an adult skeleton which exhibited extensive, complex dental restorative treatment. A putative identification of the found skeleton as a missing woman was established using circumstantial evidence found at the scene. However, it became important to establish a positive identification using reliable scientific methods. When it was discovered that antemortem dental records were not available because the treatment was completed in another country and the treating dentist could not be found, cytological smears stained with Papanicolaou (PAP) stain obtained from the putative decedent's medical records were used as a reference DNA sample. DNA was recovered from the teeth of the skeleton using cryogenic grinding. Comparison of the genotypes resulted in the conclusion that the DNA originated from the same source. The use of PAP smears in this way is seen as a valuable resource in cases where positive identification using traditional dental and medical records is not possible.

Adult↗