Megapixel Resolution Research Articles

High-speed scanning stereoscopic PIV for 3D vorticity measurement in liquids

A scanning stereo particle image velocimetry (SSPIV) system was developed to measure the three-dimensional (3D) distribution of three-component (3C) velocity in a turbulent round jet. A laser light sheet produced with a high-repetition-rate pulsed Nd:YLF laser was scanned by an optical scanner in a direction normal to the sheet. Two high-speed mega-pixel resolution C-MOS cameras captured the particle images illuminated by the light sheet, and the stereoscopic PIV method was adopted to acquire the 3D-3C velocity distribution of turbulent water flow. A water jet formed by a round nozzle with an exit diameter of D = 5 mm was diagnosed by the current technique. The jet Reynolds number was set at Re ≈ 1000, and the streamwise location of the measurement was fixed at approximately x = 45D. A measurement volume (∼100 × 100 × 100 mm3) containing 50 velocity planes was scanned in 0.22 s, which was sufficiently short to capture the instantaneous vortical structures. The residue of the continuity equation (divergence) was approximately 7% of rms vorticity on the centreline of the jet. The iso-vorticity surfaces clearly depict vortical structures in the jet shear layer.

A Simple Way to Take Pictures During Endoscopic Procedures

We describe a new method of taking pictures from endoscopic images using a digital photo camera coupled to the endoscopic lens without an adapter. We used a digital camera with 3.3 megapixel resolution and 6 x optical zoom. The camera was coupled to the endoscopic lens with no special adapter. The image was accompanied through the LCD (liquid crystal display) visor, and the picture was taken with the flash button on and with no macro resource. The image was then enlarged by optical and digital zoom before being easily stored in photo files at the personal computer. The quality of the photos obtained by this method was at least similar to that of traditional photos, and the data were promptly stored. We describe a simple method of taking pictures from endoscopic images with the additional advantage of a facility to edit and store the photographs.

A204 スキャニング・ステレオPIVによる軸対称噴流の三次元渦度計測

A scanning stereo particle image velocimetry (SSPIV) system was developed to measure the three-dimensional (3D) distribution of three-component (3C) velocity in a turbulent round jet. A laser sheet produced with a high-repetition-rate pulsed Nd:YLF laser was scanned by an optical scanner in a direction normal to the sheet. Two high-speed mega-pixel resolution C-MOS cameras captured the particle images illuminated by the light sheet, and the stereoscopic PIV method was adopted to acquire the 3D-3C velocity distribution of turbulent water flow. A water jet formed by a round nozzle with an exit diameter of D=5 mm was diagnosed by the current technique. The jet Reynolds number was set at Re ?? 1000, and streamwise locations of measurement were fixed at x=40D. A measurement volume (-100 × 100 × 100 mm 3) containing 50 velocity planes was scanned in 0.208 s, which was sufficiently short to capture the instantaneous vortical structures. The iso-vorticity surfaces clearly depict vortical structures in the jet shear layer. Development of the vortical structure was also observed by continuous laser sheet scanning.

Inhibition of chondrocyte apoptosis in vivo following acute osteochondral injury

In spite of advances and refinements in surgical technique, the development of post-traumatic arthritis following osteochondral injury remains one of the major unsolved problems faced by orthopedic surgeons. Of particular interest is the possibility that chondrocyte programmed cell death (PCD), or ‘apoptosis’, contributes to the subsequent development of post-traumatic arthritis 1–5 . Recent studies have shown that inhibitors of caspases, key enzymes in the apoptosis pathway, can block chondrocyte PCD in vitro 4–7 . The goal of the presented study was to test the hypothesis that short-term, intra-articular caspase inhibitor treatment can limit chondrocyte PCD in vivo following acute osteochondral injury. Adult New Zealand white rabbits underwent experimental osteochondral injury. One group of rabbits received daily intra-articular injections of the broadspectrum caspase inhibitor Z-VAD-fmk. A control group of rabbits received daily intra-articular injections of vehicle alone. After four days of treatment, the articular cartilage was analyzed for chondrocyte PCD. Treatment with Z-VADfmk resulted in a marked reduction in the percentage of chondrocytes undergoing PCD compared to controls [treated=7.4±1.8%; controls=32.5±8.6% (P<0.0001 by student’s t-test)]. The degree of PCD inhibition was dependent upon the distance from the site of injury, with levels of PCD reduced to background levels in areas beyond 1 mm from the drill hole. These results suggest that the intraarticular administration of PCD inhibitors may be a useful strategy for the treatment of osteochondral injury by limiting the extent of articular chondrocyte loss due to apoptosis. For these experiments, a drill with a cooled 2 mm bit was used to create osteochondral injuries in the hind limb femoral condyles of adult rabbits. The injuries were created in the weight bearing portions of the condyles and penetrated into the subchondral bone. Following surgery, five animals received daily intra-articular injections of the caspase inhibitor Z-VAD-fmk (100 µM in 0.1% DMSO, 0.5 cc; Calbiochem, CA) delivered via an indwelling catheter. A control group of five rabbits received daily intra-articular injections of vehicle alone. The knee tissue was harvested on post-injury day 4, decalcified in EDTA, embedded in paraffin, and then sectioned in the sagittal plane at 5 µm thickness for further analysis. Chondrocyte apoptosis was quantified by TUNEL analysis using the ApopTag ® Direct in situ apoptosis detection kit (Intergen, NY) with DAPI used as a counterstain. Fluorescence images were captured using appropriate filters with an Axiocam digital camera (Zeiss, NJ) at 1 megapixel resolution. Each captured field was subdivided into three ‘Zones’ with Zone 1 encompassing the full thickness of articular cartilage extending from 0 to 0.5 mm away from the drill hole; Zone 2 extending from 0.5 to 1 mm away from the drill hole; and Zone 3 extending from 1 to 1.5 mm away from the drill hole (Fig. 1). Semi-automated data collection and analysis were performed using custom

A 1.3 Megapixel Resolution Portable CCD Electronic Still Camera

ABSTRACT Portable electronic still cameras have been available for some years although, in general, the imagequality has fallen short of the 35 mmfilm quality benchmark. To obtain improved image capture andreproduction, higher resolution CCD imagers with wider dynamic ranges must be employed in thesecameras.A camera system composed of a 35 mmNikon F3 camera body, a camera back containing a CCI)-imager, and a portable hard drive for storing digitiZed images was constructed and employed to acquireimages distributed over photospace. This paper describes the camera's hardware and capabilities, the software post-processing, the camera's characteristics, and a method for evaluating the camera's performance. 1. INTRODUCTION Portable electronic still cameras possess numerous advantages as well as disadvantages compared to film-based cameras. Among the advantages are rapid image availability without the chemical processing step required by film, and direct input capability to computers for applications requiringimage data. However, while the image quality obtainable with these cameras may be acceptable fordisplay on a video monitor, their overall quality has proven to be too low for many applications. A