A twin-mirrored galvanometer laser light sheet generator

A galvanometer mirror-based laser light sheet system has been developed for use in the Basic Aerodynamics Research Tunnel at NASA Langley. This system generates and positions single or multiple light sheets over aeronautical research models being tested in the low speed tunnel. This report describes a twin mirrored galvanometer laser light sheet generator and shows typical light sheet arrangements in use. With this system, illumination of smoke entrained in the flow over a delta wing model reveals the vortical flow produced by the separation of the flow at the leading edge of the model. The light sheet system has proven to be very adaptable and easy to use in sizing and positioning light sheets in wind tunnel applications

Tumour-Associated Transplantation Antigens of Neoplasms Induced by a Naturally Occurring Murine Sarcoma Virus (FBJ-MSV)

FBJ osteosarcoma virus (FBJ-MSV) isolated originally from a spontaneously arising osteosarcoma in a CF1 mouse is the only known naturally occurring murine sarcoma virus (MSV). It is unique among strains of MSV in producing primarily sarcomata in mice. The capacity of tumour cells transformed in vivo by this agent to elicit specific transplantation immunity in syngeneic hosts was investigated. A low level of resistance (104-105 cells) was consistently induced by implantation of x-irradiated (15,000 rad) tumours or surgical excision of developing subcutaneous grafts. By contrast intraperitoneal inoculation of virus containing cellfree extracts of FBJ-MSV sarcomata was a far less effective immunization procedure. Confirmatory evidence for the antigenicity of these neoplasms was obtained in tests in which preincubation of tumour cells with lymphoid cells from specifically immune donors inhibited in vivo outgrowth of the FBJ-MSV cells in untreated syngeneic recipients. The induction of host resistance to FBJ-MSV cells by immunization with identical and independently-induced FBJ-MSV tumours established that FBJ-MSV cells possess common cell surface antigenic specificities in a manner analogous to those of experimental neoplasms induced by other oncogenic DNA and RNA viruses. Since FBJ-MSV cells release infectious virus it was not possible in this system to establish whether the tumour-rejection antigen was cellular or virion in nature. The antigenic weakness of FBJ-MSV cells in syngeneic hosts is comparable with that of virus-induced murine leukaemias of the Gross (G) or “wild” type subgroup to which category FBJ-MSV also belongs. These features suggest that FBJ-MSV exemplifies naturally occurring sarcomagenic viruses more closely than those of the Friend-Moloney-Rauscher-Graffi (FMRGr) subgroup which in general induce highly antigenic neoplasms

Cohomological Constructions of Regular Cyclic Coverings of the Platonic Maps

AbstractIn we described the regular maps and hypermaps which are cyclic coverings of the Platonic maps, branched over the face centers, vertices or midpoints of edges. Here we determine cochains by which these coverings can be explicitly constructed

THE FEDERAL AGRICULTURE IMPROVEMENT AND REFORM ACT OF 1996: COMMODITY AND CONSERVATION PROGRAMS

The Federal Agriculture Improvement and Reform Act contains major revisions in farm commodity programs. This paper summarizes the major provision of legislation. Because many program implementation rules must be developed, program participants are advised to consult their local office of the USDA Farm Service Agency for final program provisions.Agricultural and Food Policy,

A PREVIEW OF THE 1996 FARM PROGRAM PROVISIONS

The U.S. House of Representatives and Senate have written farm bills that contain major revisions in farm commodity programs. Differences in these bills, House bill HR 2854 and Senate bill S 1541, must now be resolved by a Conference Committee, approved by a final vote of both houses of Congress, and signed by the President. Though differences in the bills do exist, the bills contain many similar provisions that appear likely to be included in the final version of the bill. This paper summarizes the major provisions of these bills and identifies areas where differences must be resolved by the Conference Committee.Agricultural and Food Policy,

Zetos: Ein Kulturbelastungssystem für trabekuläre Knochen. Untersuchung eines Belastungssignals mit verschiedenen Intensitäten an bovinen Knochenzylindern

Das Ziel dieses Versuches war es, den Einfluss verschiedener Intensitäten (1000, 1500, 2000, 3000, 4000µstrain) eines physiologischen Belastungssignals (Springen) auf trabekulären Knochen zu untersuchen. Dazu wurde der Zetos: Ein Kultur- und Belastungssystem für trabekulären Knochen verwendet. 48 bovine Knochenexplantate wurden randomisiert und in 6 Gruppen (je 8) eingeteilt. 5 Belastungsgruppen und eine Kontrollgruppe. Die Knochenexplantate wurden für 26 Tage kultiviert (DMEM HighGlucose Medium) und an 23 Tagen mechanisch belastet. Vor jeder Belastung wurde täglich (belastete Gruppen) und alle 3 Tage (Kontrollgruppe) die Steifigkeit (Young's Modulus) gemessen. Bei Auswertung der Steifigkeitsmessung gab es signifikante Unterschiede (p<0,05) zwischen der Kontrollgruppe und den Belastungsgruppen ab 1500µstrain Maximalbelastung. In den Gruppen mit 1500, 2000, 3000µstrain konnte ein kontinuierlicher Steifigkeitsanstieg über den gesamten Versuchszeitraum festgestellt werden. Die Gruppe mit 4000µstrain erreichte schon nach sehr kurzer Zeit (8.Belastungstag) ein Steifigkeitsmaximum. Dies blieb bis zum Versuchende konstant. Die gemessenen Osteoiddicken in dieser Gruppe waren aber nicht größer als in den Gruppen mit 2000 und 3000µstrain. Die Gruppe mit 2000µstrain zeigte den höchsten Anteil neu gebildeten Osteoids. Diese 3 genannten Gruppen unterschieden sich aber signifikant (p<0,05) von der Kontrollgruppe. Zudem konnte eine Korrelation zwischen ansteigender Intensität und Osteoidzunahme beobachtet werden (r = 0,87). Die histologische Auswertung erfolgte an nicht entkalktem Knochen und zeigte gut erhaltene trabekuläre Strukturen sowie ebenso gut erhaltene Zellmorphologien