3D documentation of footwear impressions and tyre tracks in snow with high resolution optical surface scanning

The three-dimensional documentation of footwear and tyre impressions in snow offers an opportunity to capture additional fine detail for the identification as present photographs. For this approach, up to now, different casting methods have been used. Casting of footwear impressions in snow has always been a difficult assignment. This work demonstrates that for the three-dimensional documentation of impressions in snow the non-destructive method of 3D optical surface scanning is suitable. The new method delivers more detailed results of higher accuracy than the conventional casting techniques. The results of this easy to use and mobile 3D optical surface scanner were very satisfactory in different meteorological and snow conditions. The method is also suitable for impressions in soil, sand or other materials. In addition to the side by side comparison, the automatic comparison of the 3D models and the computation of deviations and accuracy of the data simplify the examination and delivers objective and secure results. The results can be visualized efficiently. Data exchange between investigating authorities at a national or an international level can be achieved easily with electronic data carriers.

Aortic rupture in high-speed skiing crashes

BACKGROUND: New equipment and techniques in winter sports, such as carving skis and snowboards, have brought up new trauma patterns into the spectrum of leisure trauma. The injuries resemble high-energy trauma known from road crashes. The aim of the present study was to assess the incidence of acute traumatic descending aortic rupture in recreational skiing-crashes. MATERIAL: Between January 1995 and December 2004, 22 patients were admitted to our hospital for aortic rupture. Four patients had skiing crashes (18.2%). Mean age was 31 years, all patients were male. In two cases, aortic rupture was associated with fractures of the upper and lower extremities. One patient additionally had a cerebral contusion with an initial Glasgow Coma Scale score of 13. In two patients, isolated aortic rupture was diagnosed. RESULTS: Two patients were treated by graft interposition, and one by endograft. One patient arrived under mechanical resuscitation without blood pressure. He died at admission. He had been observed for 5 hours in another hospital, complaining of severe intrascapular back pain, before transport to our trauma unit for unknown bleeding. In the other three cases, treatment was successful. CONCLUSION: Rescue services and paramedics should be aware of this new type of injury. Acute aortic rupture has to be considered as possible injury in high velocity skiing crashes.

In vivo measurement of central corneal thickness in normal chicks (Gallus gallus domesticus) with the optical low-coherence reflectometer

OBJECTIVE To determine the practicability and accuracy of central corneal thickness (CCT) measurements in living chicks utilizing a noncontact, high-speed optical low-coherence reflectometer (OLCR) mounted on a slit lamp. ANIMALS STUDIED Twelve male chicks (Gallus gallus domesticus). Procedures  Measurements of CCT were obtained in triplicate in 24 eyes of twelve 1-day-old anaesthetized chicks using OLCR. Every single measurement taken by OLCR consisted of the average result of 20 scans obtained within seconds. Additionally, corneal thickness was determined histologically after immersion fixation in Karnovsky's solution alone (20 eyes) or with a previous injection of the fixative into the anterior chamber before enucleation (4 eyes). RESULTS Central corneal thickness measurements using OLCR in 1-day-old living chicks provide a rapid and feasible examination technique. Mean CCT measured with OLCR (189.7 ± 3.34 μm) was significantly lower than histological measurements (242.1 ± 47.27 μm) in eyes with fixation in Karnovsky's solution (P = 0.0005). In eyes with additional injection of Karnovsky's fixative into the anterior chamber, mean histologically determined CCT was 195.2 ± 8.25 μm vs. 191.9 ± 8.90 μm with OLCR. A trend for a lower variance was found compared to the eyes that had only been immersion fixed. CONCLUSION Optical low-coherence reflectometry is an accurate examination technique to measure in vivo CCT in the eye of newborn chicks. The knowledge of the thickness of the chick cornea and the ability to obtain noninvasive, noncontact measurements of CCT in the living animal may be of interest for research and development of eye diseases in chick models.

Structure determination of channel and transport proteins by high-resolution microscopy techniques

High-resolution microscopy techniques provide a plethora of information on biological structures from the cellular level down to the molecular level. In this review, we present the unique capabilities of transmission electron and atomic force microscopy to assess the structure, oligomeric state, function and dynamics of channel and transport proteins in their native environment, the lipid bilayer. Most importantly, membrane proteins can be visualized in the frozen-hydrated state and in buffer solution by cryo-transmission electron and atomic force microscopy, respectively. We also illustrate the potential of the scintillation proximity assay to study substrate binding of detergent-solubilized transporters prior to crystallization and structural characterization.

High-speed rotational atherectomy before paclitaxel-eluting stent implantation in complex calcified coronary lesions: the randomized ROTAXUS (Rotational Atherectomy Prior to Taxus Stent Treatment for Complex Native Coronary Artery Disease) trial

OBJECTIVES This study sought to determine the effect of rotational atherectomy (RA) on drug-eluting stent (DES) effectiveness. BACKGROUND DES are frequently used in complex lesions, including calcified stenoses, which may challenge DES delivery, expansion, and effectiveness. RA can adequately modify calcified plaques and facilitate stent delivery and expansion. Its impact on DES effectiveness is widely unknown. METHODS The ROTAXUS (Rotational Atherectomy Prior to TAXUS Stent Treatment for Complex Native Coronary Artery Disease) study randomly assigned 240 patients with complex calcified native coronary lesions to RA followed by stenting (n = 120) or stenting without RA (n = 120, standard therapy group). Stenting was performed using a polymer-based slow-release paclitaxel-eluting stent. The primary endpoint was in-stent late lumen loss at 9 months. Secondary endpoints included angiographic and strategy success, binary restenosis, definite stent thrombosis, and major adverse cardiac events at 9 months. RESULTS Despite similar baseline characteristics, significantly more patients in the standard therapy group were crossed over (12.5% vs. 4.2%, p = 0.02), resulting in higher strategy success in the rotablation group (92.5% vs. 83.3%, p = 0.03). At 9 months, in-stent late lumen loss was higher in the rotablation group (0.44 ± 0.58 vs. 0.31 ± 0.52, p = 0.04), despite an initially higher acute lumen gain (1.56 ± 0.43 vs. 1.44 ± 0.49 mm, p = 0.01). In-stent binary restenosis (11.4% vs. 10.6%, p = 0.71), target lesion revascularization (11.7% vs. 12.5%, p = 0.84), definite stent thrombosis (0.8% vs. 0%, p = 1.0), and major adverse cardiac events (24.2% vs. 28.3%, p = 0.46) were similar in both groups. CONCLUSIONS Routine lesion preparation using RA did not reduce late lumen loss of DES at 9 months. Balloon dilation with only provisional rotablation remains the default strategy for complex calcified lesions before DES implantation.

Assessment of ultra-high resolution optical coherence tomography for monitoring tissue effects caused by laser photocoagulation of ex-vivo porcine retina

Retinal laser photocoagulation is an established and successful treatment for a variety of retinal diseases. While being a valuable treatment modality, laser photocoagulation shows the drawback of employing high energy lasers which are capable of physically destroying the neural retina. For reliable therapy, it is therefore crucial to closely monitor the therapy effects caused in the retinal tissue. A depth resolved representation of optical tissue properties as provided by optical coherence tomography may provide valuable information about the treatment effects in the retinal layers if recorded simultaneously to laser coagulation. Therefore, in this work, the use of ultra-high resolution optical coherence tomography to represent tissue changes caused by conventional and selective retinal photocoagulation is investigated. Laser lesions were placed on porcine retina ex-vivo using a 577 nm laser as well as a pulsed laser at 527 nm built for selective treatment of the retinal pigment epithelium. Applied energies were varied to generate lesions best representing the span from under- to overtreatment. The lesions were examined using a custom-designed optical coherence tomography system with an axial resolution of 1.78 μm and 70 kHz Ascan rate. Optical coherence tomography scans included volume scans before and after irradiation, as well as time lapse scans (Mscan) of the lesions. Results show OCT lesion visibility thresholds to be below the thresholds of ophthalmoscopic inspection. With the ultra-high resolution OCT, 42% - 44% of ophthalmoscopically invisible lesions could be detected and lesions that were under- or overexposed could be distinguished using the OCT data.

Optical Light Curve Observations to Determine Attitude States of Space Debris

The currently proposed space debris remediation measures include the active removal of large objects and “just in time” collision avoidance by deviating the objects using, e.g., ground-based lasers. Both techniques require precise knowledge of the attitude state and state changes of the target objects. In the former case, to devise methods to grapple the target by a tug spacecraft, in the latter, to precisely propagate the orbits of potential collision partners as disturbing forces like air drag and solar radiation pressure depend on the attitude of the objects. Non-resolving optical observations of the magnitude variations, so-called light curves, are a promising technique to determine rotation or tumbling rates and the orientations of the actual rotation axis of objects, as well as their temporal changes. The 1-meter telescope ZIMLAT of the Astronomical Institute of the University of Bern has been used to collect light curves of MEO and GEO objects for a considerable period of time. Recently, light curves of Low Earth Orbit (LEO) targets were acquired as well. We present different observation methods, including active tracking using a CCD subframe readout technique, and the use of a high-speed scientific CMOS camera. Technical challenges when tracking objects with poor orbit redictions, as well as different data reduction methods are addressed. Results from a survey of abandoned rocket upper stages in LEO, examples of abandoned payloads and observations of high area-to-mass ratio debris will be resented. Eventually, first results of the analysis of these light curves are provided.