A novel method for linking between a 3D printer and printed objects using toolmark comparison techniques.

Rapid advances and decreased production costs in 3D printing (3DP) have resulted in its accelerated implementation in criminal activities. Fused Deposition Modeling (FDM (3DP and Polylactic Acid (PLA) filament were chosen for the current research because they are widely used in commodity 3DP, particularly in documented criminal activities. This study shows how specific features of 3DP along with classical toolmark comparison techniques using Stereo-Microscopy and Comparison Microscopy can be used to link between two 3DP objects as well as between a printed object and a suspected 3D printer. Links are determined based on random fine marks found on the 3DP's heated stage (bed) that are replicated to the base face of the printed object. Melted filament that extrudes from the nozzle of the FDM 3DP constructs the base face of the printed object. This melted filament functions as a "casting material" after it cools down and solidifies, enabling replication of the fine marks. The observed resolution of these marks is as high as the resolution of casting material dedicated for toolmark replications. Overall, this study demonstrates a novel forensic method based on toolmark comparison for linking between a 3D printer and its printed objects.

A novel technology for reversible fallopian tubal occlusion using a reverse thermo-responsive polymer-Preliminary results from a rabbit animal study.

OBJECTIVES: To determine if PF-88, a reverse thermo-responsive polymer designed to create a gel at body temperature and liquefy at a lower temperature (21°C) can reversibly occlude the fallopian tubes in rabbits. STUDY DESIGN: Mature female New Zealand White rabbits underwent laparotomy and placement of 22-gage catheter into the lumen of the distil uterine horns for evaluation of tubal patency by fluoroscopy using radio opaque contrast and treatment with PF-88. In the Acute Phase group (n = 5) after PF-88 treatment we immediately cooled the serosal surface of the tube with ice for 90 seconds to liquify the gel then reassessed patency. In the Survival Phase groups, animals recovered from the initial surgery and then underwent a second procedure for evaluation of tubal occlusion and reversibility at 4 (n = 3), 14 (n = 2), and 28 (n = 3) weeks after the initial procedure. We compared the histologic appearance of the treated fallopian tubes to untreated controls (n = 3). RESULTS: In the Acute Phase, we found all 10 fallopian tubes patent on initial evaluation, occluded following treatment with PF88, and patent following re-liquification by chilling. Animals in the Survival Group, all but one of the treated tubes appeared blocked at follow-up and patent following chilling. The treatment failure occurred in an animal in the 4-week group. Tubes treated with PF88 showed no histologic evidence of residual material or damage after removal of the polymer. CONCLUSION: The PF-88 reverse thermo-responsive polymer demonstrated the ability to reversibly block fallopian tubes for up to 28 weeks. IMPLICATIONS: The demonstration of reversible occlusion of the fallopian tube of rabbits using PF-88, a thermo-responsive reverse polymer, support additional studies to evaluate the potential of this polymer as a contraceptive in women.

In Situ Generated Medical Devices.

Medical devices play a major role in all areas of modern medicine, largely contributing to the success of clinical procedures and to the health of patients worldwide. They span from simple commodity products such as gauzes and catheters, to highly advanced implants, e.g., heart valves and vascular grafts. In situ generated devices are an important family of devices that are formed at their site of clinical function that have distinct advantages. Among them, since they are formed within the body, they only require minimally invasive procedures, avoiding the pain and risks associated with open surgery. These devices also display enhanced conformability to local tissues and can reach sites that otherwise are inaccessible. This review aims at shedding light on the unique features of in situ generated devices and to underscore leading trends in the field, as they are reflected by key developments recently in the field over the last several years. Since the uniqueness of these devices stems from their in situ generation, the way they are formed is crucial. It is because of this fact that in this review, the medical devices are classified depending on whether their in situ generation entails chemical or physical phenomena.