1,144 research outputs found
Homotransplantation of multiple visceral organs
It was technically possible to perform simultaneous homotransplantation of multiple visceral organs including the liver, spleen, pancreas, omentum and the entire gastrointestinal tract. Arterialization of the cooled graft was accomplished through the donor aorta which was removed with the graft and attached to that of the recipient dog. Gastrointestinal hemorrhage after surgery accounted for a high operative mortality and was thought to be due to denervation of the graft. The five dogs which survived the immediate trauma of surgery lived for five and a half to nine days. After the second day, these animals were physically active and able to resume oral alimentation. In three dogs, there was metabolic evidence of rejection of the liver. In two others, jaundice did not develop. These observations were compared with chemical, hematologic and pathologic data obtained in previous experiments involving homotransplantation of the liver alone. In some cases, there was less evidence of host versus graft rejection after the multiple organ transplants. Other data in the present study suggested the possibility that a significant graft versus host reaction may have been an important contributory cause of death. Β© 1962
Effects of Substituents on the Length of Central C(sp^3)-C(sp^3) Bond in Anthracene Photodimers and Related Molecules
Effects of substituents on the lengths of the central CβC single bond in the butterfly-shaped anthracene photodimers (1)β(7) and lepidopterenes (8) are studied. X-Ray analysis of the photodimer (10) of 9,10-difluoroanthracene gave a C(9)βC(10β²) bond length of 1.631 (3)Γ
. An attempt to re-determine molecular structure of the photoisomer (5) of [2.2](9,10) anthracenophane (12) by neutron diffraction analysis is also reported [C(9)βC(10β²): obs. 1.64(1), calc. 1.63(1)Γ
]. The D_2 structure that had been proposed for the minimum-energy conformation of (5) is questioned and the D_(2h) symmetric conformation is suggested on the basis of the diffraction results and MNDO calculations. The experimentally determined distances of the long central CβC bonds in these butterfly compounds including dianthronyl (9) are well reproduced by MNDO calculations with a standard deviation of 0.013 Γ
. Small but significant further elongation of the central CβC bond by up to 0.07 Γ
resulting from annulation of cyclobutane or cyclopentane ring in anthracene photodimers and from remote chlorine substitution in lepidopterene are interpreted in terms of the increased ΟβΟ^* orbital interaction
Analysis of geologic terrain models for determination of optimum SAR sensor configuration and optimum information extraction for exploration of global non-renewable resources. Pilot study: Arkansas Remote Sensing Laboratory, part 1, part 2, and part 3
Computer-generated radar simulations and mathematical geologic terrain models were used to establish the optimum radar sensor operating parameters for geologic research. An initial set of mathematical geologic terrain models was created for three basic landforms and families of simulated radar images were prepared from these models for numerous interacting sensor, platform, and terrain variables. The tradeoffs between the various sensor parameters and the quantity and quality of the extractable geologic data were investigated as well as the development of automated techniques of digital SAR image analysis. Initial work on a texture analysis of SEASAT SAR imagery is reported. Computer-generated radar simulations are shown for combinations of two geologic models and three SAR angles of incidence
The steering gaits of sperm
Sperm are highly specialized cells, which have been subject to substantial evolutionary pressure. Whereas some sperm features are highly conserved, others have undergone major modifications. Some of these variations are driven by adaptation to mating behaviours or fitness at the organismic level. Others represent alternative solutions to the same task. Sperm must find the egg for fertilization. During this task, sperm rely on long slender appendages termed flagella that serve as sensory antennas, propellers and steering rudders. The beat of the flagellum is periodic. The resulting travelling wave generates the necessary thrust for propulsion in the fluid. Recent studies reveal that, for steering, different species rely on different fundamental features of the beat wave. Here, we discuss some examples of unity and diversity across sperm from different species with a particular emphasis on the steering mechanisms. This article is part of the Theo Murphy meeting issue βUnity and diversity of cilia in locomotion and transportβ
Investigation of Molecular Iridium Fluorides IrFn (n=1β6): A Combined Matrix-Isolation and Quantum-Chemical Study
The photo-initiated defluorination of iridium hexafluoride (IrF6) was investigated in neon and argon matrices at 6β
K, and their photoproducts are characterized by IR and UV-vis spectroscopies as well as quantum-chemical calculations. The primary photoproducts obtained after irradiation with Ξ»=365β
nm are iridium pentafluoride (IrF5) and iridium trifluoride (IrF3), while longer irradiation of the same matrix with Ξ»=278β
nm produced iridium tetrafluoride (IrF4) and iridium difluoride (IrF2) by IrβF bond cleavage or F2 elimination. In addition, IrF5 can be reversed to IrF6 by adding a F atom when exposed to blue-light (Ξ»=470β
nm) irradiation. Laser irradiation (Ξ»=266β
nm) of IrF4 also generated IrF6, IrF5, IrF3 and IrF2. Alternatively, molecular binary iridium fluorides IrFn (n=1β6) were produced by co-deposition of laser-ablated iridium atoms with elemental fluorine in excess neon and argon matrices under cryogenic conditions. Computational studies up to scalar relativistic CCSD(T)/triple-ΞΆ level and two-component quasirelativistic DFT computations including spin-orbit coupling effects supported the formation of these products and provided detailed insights into their molecular structures by their characteristic IrβF stretching bands. Compared to the Jahn-Teller effect, the influence of spin-orbit coupling dominates in IrF5, leading to a triplet ground state with C4v symmetry, which was spectroscopically detected in solid argon and neon matrices
ΠΡΠΎΠ±Π»Π΅ΠΌΡ Π³Π΅ΠΎΠ»ΠΎΠ³ΠΈΠΈ ΠΈ ΠΎΡΠ²ΠΎΠ΅Π½ΠΈΡ Π½Π΅Π΄Ρ. Π’. 2
Π ΡΠ±ΠΎΡΠ½ΠΈΠΊΠ΅ ΠΎΡΡΠ°ΠΆΠ΅Π½Ρ ΠΏΡΠΎΠ±Π»Π΅ΠΌΡ ΠΏΠ°Π»Π΅ΠΎΠ½ΡΠΎΠ»ΠΎΠ³ΠΈΠΈ, ΡΡΡΠ°ΡΠΈΠ³ΡΠ°ΡΠΈΠΈ, ΡΠ΅ΠΊΡΠΎΠ½ΠΈΠΊΠΈ, ΠΈΡΡΠΎΡΠΈΡΠ΅ΡΠΊΠΎΠΉ ΠΈ ΡΠ΅Π³ΠΈΠΎΠ½Π°Π»ΡΠ½ΠΎΠΉ Π³Π΅ΠΎΠ»ΠΎΠ³ΠΈΠΈ, ΠΌΠΈΠ½Π΅ΡΠ°Π»ΠΎΠ³ΠΈΠΈ, Π³Π΅ΠΎΡ
ΠΈΠΌΠΈΠΈ, ΠΏΠ΅ΡΡΠΎΠ»ΠΎΠ³ΠΈΠΈ, Π»ΠΈΡΠΎΠ»ΠΎΠ³ΠΈΠΈ, ΠΏΠΎΠ»Π΅Π·Π½ΡΡ
ΠΈΡΠΊΠΎΠΏΠ°Π΅ΠΌΡΡ
, ΠΌΠ΅ΡΠ°Π»Π»ΠΎΠ³Π΅Π½ΠΈΠΈ, Π³ΠΈΠ΄ΡΠΎΠ³Π΅ΠΎΠ»ΠΎΠ³ΠΈΠΈ, Π³ΠΈΠ΄ΡΠΎΠ³Π΅ΠΎΡ
ΠΈΠΌΠΈΠΈ, ΠΈΠ½ΠΆΠ΅Π½Π΅ΡΠ½ΠΎΠΉ Π³Π΅ΠΎΠ»ΠΎΠ³ΠΈΠΈ, Π³Π΅ΠΎΡΠΈΠ·ΠΈΠΊΠΈ, Π½Π΅ΡΡΡΠ½ΠΎΠΉ Π³Π΅ΠΎΠ»ΠΎΠ³ΠΈΠΈ, Π³Π΅ΠΎΠΈΠ½ΡΠΎΡΠΌΠ°ΡΠΈΠΎΠ½Π½ΡΡ
ΡΠΈΡΡΠ΅ΠΌ Π² Π³Π΅ΠΎΠ»ΠΎΠ³ΠΈΠΈ, ΡΠ°Π·ΡΠ°Π±ΠΎΡΠΊΠΈ Π½Π΅ΡΡΡΠ½ΡΡ
ΠΈ Π³Π°Π·ΠΎΠ²ΡΡ
ΠΌΠ΅ΡΡΠΎΡΠΎΠΆΠ΄Π΅Π½ΠΈΠΉ, ΠΏΠ΅ΡΠ΅ΡΠ°Π±ΠΎΡΠΊΠΈ ΡΠ³Π»Π΅Π²ΠΎΠ΄ΠΎΡΠΎΠ΄Π½ΠΎΠ³ΠΎ ΠΈ ΠΌΠΈΠ½Π΅ΡΠ°Π»ΡΠ½ΠΎΠ³ΠΎ ΡΡΡΡΡ, Π½Π΅ΡΡΠ΅Π³Π°Π·ΠΎΠΏΡΠΎΠΌΡΡΠ»ΠΎΠ²ΠΎΠ³ΠΎ ΠΎΠ±ΠΎΡΡΠ΄ΠΎΠ²Π°Π½ΠΈΡ, Π±ΡΡΠ΅Π½ΠΈΡ Π½Π΅ΡΡΡΠ½ΡΡ
ΠΈ Π³Π°Π·ΠΎΠ²ΡΡ
ΡΠΊΠ²Π°ΠΆΠΈΠ½, ΡΠ΅Ρ
Π½ΠΈΠΊΠΈ ΠΈ ΡΠ΅Ρ
Π½ΠΎΠ»ΠΎΠ³ΠΈΠΈ ΡΠ°Π·Π²Π΅Π΄ΠΊΠΈ ΠΈ Π΄ΠΎΠ±ΡΡΠΈ, ΡΡΠ°Π½ΡΠΏΠΎΡΡΠ° ΠΈ Ρ
ΡΠ°Π½Π΅Π½ΠΈΡ Π½Π΅ΡΡΠΈ ΠΈ Π³Π°Π·Π°, Π³ΠΎΡΠ½ΠΎΠ³ΠΎ Π΄Π΅Π»Π°, ΡΠ΅Ρ
Π½ΠΎΠ»ΠΎΠ³ΠΈΠΈ ΠΈ ΡΠ΅Ρ
Π½ΠΈΠΊΠΈ ΡΠ°Π·Π²Π΅Π΄ΠΊΠΈ ΠΌΠ΅ΡΡΠΎΡΠΎΠΆΠ΄Π΅Π½ΠΈΠΉ ΠΏΠΎΠ»Π΅Π·Π½ΡΡ
ΠΈΡΠΊΠΎΠΏΠ°Π΅ΠΌΡΡ
, Π³Π΅ΠΎΡΠΊΠΎΠ»ΠΎΠ³ΠΈΠΈ, Π³ΠΈΠ΄ΡΠΎΠ³Π΅ΠΎΡΠΊΠΎΠ»ΠΎΠ³ΠΈΠΈ, ΠΎΡ
ΡΠ°Π½Ρ ΠΈ ΠΈΠ½ΠΆΠ΅Π½Π΅ΡΠ½ΠΎΠΉ Π·Π°ΡΠΈΡΡ ΠΎΠΊΡΡΠΆΠ°ΡΡΠ΅ΠΉ ΡΡΠ΅Π΄Ρ, ΠΊΠΎΠΌΠΏΠ»Π΅ΠΊΡΠ½ΠΎΠ³ΠΎ ΠΈΡΠΏΠΎΠ»ΡΠ·ΠΎΠ²Π°Π½ΠΈΡ ΠΌΠΈΠ½Π΅ΡΠ°Π»ΡΠ½ΠΎΠ³ΠΎ ΡΡΡΡΡ, Π·Π΅ΠΌΠ»Π΅ΡΡΡΡΠΎΠΉΡΡΠ²Π°, ΡΠΊΠΎΠ½ΠΎΠΌΠΈΠΊΠΈ ΠΌΠΈΠ½Π΅ΡΠ°Π»ΡΠ½ΠΎΠ³ΠΎ ΡΡΡΡΡ ΠΈ Π³ΠΎΡΠ½ΠΎΠ³ΠΎ ΠΏΡΠ°Π²Π°
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