Phenomenological study of subsonic turbulent flow over a swept rearward-facing step

The phenomenology of turbulent, subsonic flow over a swept, rearward-facing step was studied. Effects of variations in step height, sweep angle, base geometry, and end conditions on the 3-D separated flow were examined. The separated flow was visualized using smoke wire, oil drop, and surface tuft techniques. Measurements include surface pressure, reattachment distance and swirl angle. Results indicate: (1) model/test section coupling affects the structure of the separated flow, but spanwise end conditions do not; (2) the independence principle is evidently valid for sweep angles up to 38 deg; (3) a sweep angle/swirl angle correlation exists; and (4) base modifications can significantly reduce the reattachment distance

Vapor-screen flow-visualization experiments in the NASA Langley 0.3-m transonic cryogenic tunnel

The vortical flow on the leeward side of a delta-wing model has been visualized at several different tunnel conditions in the NASA Langley 0.3-Meter Transonic Cryogenic Tunnel using a vapor-screen flow-visualization technique. Vapor-screen photographs of the subject flow field are presented and interpreted relative to phenomenological implications. Results indicate that the use of nitrogen fog in conjunction with the vapor-screen technique is feasibile

Clonogenic cell survival in cryopreserved human tumour cells.

Cells from 3 human tumours have been grown in soft agar contained in Millipore diffusion chambers and implanted i.p. in mice. Clonal growth was obtained from fresh biopsy samples, from cryopreserved tissue, and from xenografts of the tissues in immune-suppressed mice. The radiosensitivities of a melanoma and an ovarian carcinoma were evaluated by in vitro irradiation before assay for colony formation. Xenografting did not modify the radiosensitivity of the melanoma. Cells from another tumour were exposed to Adriamycin or cyclophosphamide whilst contained within i.p. diffusion chambers; the sensitivity was similar for cryopreserved and xenografted cells. The results encourage further attempts to quantify the sensitivity of human tumour cells by these methods

A modified technique of orthotopic transplant of the kidney in rabbits

In this study kidneys were harvested from bred-for-research cats weighing 4 to 5 kg. General principles of donor bilateral nephrectomy en bloc with aorta, vena cava, renal vessels, and ureters were followed. After the harvest the grafts were placed in lactated Ringer slush. A cuff was prepared on the renal vein over a 10 French plastic tube. The aorta was divided and left in connection with the renal artery at each side. Twenty female checkered Flemish giant rabbits weighing 4.0-6.0 kg served as recipients. After premedication with 40 mg/kg of ketamine, anesthesia was maintained with repeated doses (every 10-15 min) of a 0.1-mL mixture of 5 parts ketamine and 1 part acepromazine diluted 50% in a normal saline. Arterial pressure, CVP, blood gases, and temperature were monitored. Through a limited midline incision a native left nephrectomy was performed. The venous anastomosis was performed with a cuff technique without clamping the vena cava (which causes severe hemodynamic instability); the anastomotic time was 2-3 min. The arterial anastomosis was performed with an end-to-side aorta-to-aorta anastomosis; the anastomotic time was 5 to 7 min. There were no episodes of venous or arterial thrombosis. The donor procedure took approximately 40 min, and the backtable preparation of the graft an additional 45 to 60 min. Preparation of the recipient for the anastomosis took 15 min and the anastomotic time (warm ischemia) was 13 +/- 5 min. In this model suitable for xenograft research the duration of the surgery in the recipient has been greatly reduced because of (1) the previous backtable preparation of the graft, and (2) the cuff technique used for venous anastomosis. The present anesthesia regimen and careful hemodynamic monitoring were also important in the success of this model

Spontaneous regression of human acute myeloid leukaemia xenografts and phenotypic evidence for maturation.

A population of human AML cells which have a characteristic karyotypic marker was cryopreserved and then grown in short-term liquid culture for 2 weeks, during which time the cells increased about 7-fold in number and progressively acquired characteristics of macrophages. 10(7) cells obtained after 1 day in culture, when they were almost devoid of Fc receptors (Fc-), on inoculation into immune-deprived mice gave rise to tumours in more than 90% of the animals. However, after 13 days of culture, when almost all the cells had Fc receptors (Fc+), a similar inoculum did not grow as tumours. After 7 days in culture the cells were heterogeneous, and divided about equally into Fc+ and Fc- cells, both of which were replicating. The Fc- population was capable of producing tumours, whereas the Fc+ was not. Of 23 assessable xenograft tumours produced by the AML cells, 14 regressed completely, 4 grew progressively and 5 grew progressively after initial regression. Progressive tumours could be further transplanted. The regression may arise as a result of maturation in vivo similar to that seen in vitro