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In a companion paper we examined whether combinations of K

We examined whether combinations of K

This article introduces the dental investigator to the basic concepts of digital imaging techniques as they apply to crime scene photographic evidence. In all aspects of forensic dentistry, analytical comparison methods demand rigorous attention to scale dimensions and the detection of photographic distortion in images of forensic interest. Dental radiographs, photographic slides, negatives, prints, and digital images are all amenable to digital techniques that are useful in controlling quality and expanding the abilities of the forensic dentist to compare known and questioned evidence. The intent of this article is to show accurate means of measuring physical parameters of dental evidence, correction of common photographic distortion and size discrepancies, elimination of examiner subjectivity, better control of image visualization, and standardization of comparison procedures.

This article exposes the dental profession in the legal environment and the rules that control the acceptance or rejection of expert witness testimony. Written by a practicing dentist and attorney, the author believes that the new forensic dentistry aspirant should develop mentoring relationships with more experienced medico-legal professionals to supplement traditional dental education.

Three photosynthetic complexes, light-harvesting complex 2 (LH2), light-harvesting complex 1 (LH1), and the reaction centre-light-harvesting complex 1 photounit (RC-LH1), were purified from a single species of a purple bacterium, Rhodobacter sphaeroides, and reconstituted into two-dimensional (2-D) crystals. Vesicular 2-D crystals of LH1 and RC-LH1 were imaged in negative stain and projection maps at 25 A resolution were produced. The rings formed by LH1 have approximately the same mean diameter as the LH1 rings from Rhodospirillum rubrum ( approximately 90 A) and therefore are likely to be composed of 15 to 17 alphabeta subunits. In the projection map calculated from the RC-LH1 2-D crystals, the reaction centre is represented by an additional density in the centre of the ring formed by the LH1 subunits. The marked improvement of shape and fine structure after a rotational pre-alignment of the RC-LH1 unit cells before averaging strongly suggests that the RC is not in a unique orientation within the LH1 rings. Tubular crystals of LH2 showed a high degree of order and allowed calculation of a projection map at 6 A resolution from glucose-embedded specimens. The projection structure shows a ring of nine alphabeta subunits. Variation of the alpha-helical projection densities suggests that the 9-fold symmetry axis is tilted with respect to the membrane normal.

The aging of bitemarks through the subjective interpretation of visual signs has created an area of controversy in the forensic science community. The healing dynamics of these bite wounds has been insufficiently studied and is poorly understood. A review of the literature related to bitemark aging was undertaken in an effort to summarize the currently published information on this misunderstood subject.

This is a case study in the application of a laboratory technique first described by Dr. Brion C. Smith in the Journal of Forensic Sciences in January 1992. Our study evaluated a human skull that showed perimortem and/or postmortem tooth loss. It was discovered in 1991 and deemed to have no usable dental information due to severe alveolar bone destruction. In 1994, using minor modifications of Dr. Smith's technique, we sealed off the open tooth sockets and injected a radiopaque material which, after radiographic analysis, revealed previously unobserved dental information. This report demonstrates that root morphology can be reconstructed. This yields radiographic information that may be useful in the identification of unknown human remains.

Patients with diffuse pulmonary infiltrates often require biopsy for a diagnosis. Standard operative therapy, open wedge resection via thoracotomy, is associated with known morbidity. We hypothesized that closed thoracoscopic wedge resection may result in reduced morbidity and decreased duration of hospital stay. This retrospective study compares open resection with thoracoscopic wedge resection in patients with diffuse pulmonary infiltrates.Seventy-five patients with diffuse pulmonary infiltrates underwent diagnostic lung biopsy. Patients requiring mechanical ventilation and high levels of pressure support before biopsy were excluded from the study. Between March 1987 and September 1991, a total of 28 patients underwent open wedge resection via lateral thoracotomy. Since April 1991, a total of 47 patients underwent thoracoscopic resection.There was no difference between the groups in age, sex, presence of immunosuppression, or final pathologic diagnosis. Adequate tissue was obtained for pathologic diagnosis in all patients of both groups. All surgeons believed that thoracoscopic biopsy provided better visualization of the entire lung than did a limited thoracotomy. Mean operative time was 69 minutes for open biopsies and 93 minutes for thoracoscopic biopsies [p = 0.038]. Mean duration of chest tube drainage was not significantly different between the two groups. Duration of hospital stay was significantly less for thoracoscopic biopsy (4.9 days) than for open biopsy (12.2 days) (p = 0.018). Fourteen of 28 open biopsies resulted in complications compared with 9 of 47 closed biopsies (p = 0.009). There were 6 deaths among patients having open biopsies and 3 deaths among those having closed biopsies (p = not significant).A significant decrease in hospital stay was noted with thoracoscopic biopsy when compared with lung biopsy via the standard open approaches. Thoracoscopy provided excellent visualization and allowed for wedge resection that provided adequate tissue for diagnosis in patients with diffuse pulmonary interstitial disease.

Physical comparison of a suspect's teeth to a bite mark injury using hollow volume comparison overlays is a common forensic odontology technique. Several methods are used to record characteristics of the size, shape and position of the teeth and to generate overlays. These include computer-based, radiographic, xerographic and hand-traced methods. Five common overlay production methods were compared using digital images of dental study casts as a reference standard. Area of the biting edges of the anterior teeth and relative rotation of each anterior tooth were measured and compared. The computer-based production method was determined to be the most accurate of those studied. It produced accurate representations of the biting edges of the teeth in an objective manner. The radiographic method was determined to be more accurate than the xerographic method with respect to tooth area measurement. The opposite is true with respect to tooth rotation. Hand-traced methods, from either wax impressions of teeth or directly from study casts, were determined to be inaccurate and subjective. It is recommended that forensic odontologists discontinue the use of hand-traced overlays in bite mark comparison cases.