Combustion of hydrogen injected into a supersonic airstream (a guide to the HISS computer program)

A computer program based on a finite-difference, implicit numerical integration scheme is described for the prediction of hydrogen injected into a supersonic airstream at an angle ranging from normal to parallel to the airstream main flow direction. Results of calculations for flow and thermal property distributions were compared with 'cold flow data' taken by NASA/Langley and show excellent correlation. Typical results for equilibrium combustion are presented and exhibit qualitatively plausible behavior. Computer time required for a given case is approximately one minute on a CDC 7600. A discussion of the assumption of parabolic flow in the injection region is given which demonstrates that improvement in calculation in this region could be obtained by a partially-parabolic procedure which has been developed. It is concluded that the technique described provides an efficient and reliable means for analyzing hydrogen injection into supersonic airstreams and the subsequent combustion

Effect of continuous gamma-ray exposure on performance of learned tasks and effect of subsequent fractionated exposures on blood-forming tissue

Sixteen monkeys trained to perform continuous and discrete-avoidance and fixed-ratio tasks with visual and auditory cues were performance-tested before, during, and after 10-day gamma-ray exposures totaling 0, 500, 750, and 1000 rads. Approximately 14 months after the performance-test exposures, surviving animals were exposed to 100-rad gamma-ray fractions at 56-day intervals to observe injury and recovery patterns of blood-forming tissues. The fixed-ratio, food-reward task performance showed a transient decline in all dose groups within 24 hours of the start of gamma-ray exposure, followed by recovery to normal food-consumption levels within 48 to 72 hours. Avoidance tasks were performed successfully by all groups during the 10-day exposure, but reaction times of the two higher dose-rate groups in which animals received 3 and 4 rads per hour or total doses of 750 and 1000 rads, respectively, were somewhat slower

The structure of triphenylgermanium hydroxide

C18H~6GeO, Mr = 320.9, triclinic, Pi, a = 15.408 (6), b = 19.974 (7), c = 23.264 (11) A, a = 107.78 (4), 13 = 1.03.54 (4), y= 101.51 (3) °, V = 6338 (5)/~3, Z = 16, Dx = 1.34 g cm -3, a(Mo Ka) = 0.71073A, /z = 19.1cm-1, F(000)=2624, T= 293 K, R = 0.055 for 6846 observed reflections. The eight independent molecules in the asymmetric unit form two independent O--H...O hydrogen-bonded tetramers with the O atoms in a flattened tetrahedral arrangement [hydrogen-bond distances in the range 2.609 (11) to 2.657 (11)A]. The Ge atoms are tetrahedrally coordinated with mean Gc O 1.791 (7) and Gc C 1.931 (8) A

Twisted [(R3P)PdX] groups above dicarbaborane ligands: 4-dimethylsulfido-3-iodo-3-triphenylphosphine-closo-3-pallada-1,2-dicarbadodecaborane and 3-dimethylphenylphosphine-3-chloro-4-dimethylsulfido-closo-3-pallada-1,2-dicarbadodecaborane

The structural analyses of [3-(PPh₃)-3-I-4-(SMe₂)-closo-3,1,2-PdC₂B₉H₁₀] or [Pd(C₄H₁₆B₉S)I(C₁₈H₁₅P)], (I), and [3-(PPhMe₂)-3-Cl-4-(SMe₂)-closo-3,1,2-PdC₂B₉H₁₀] or [Pd(C₄H₁₆B₉S)Cl(C₈H₁₁P)], (II), show that in comparison with [3-(PR₃)2-closo-3,1,2-PdC₂B₉H₁₁] the presence of the 4-SMe₂ group causes the [PdX(PR₃)] unit (X = halogen) to twist about an axis passing through the Pd atom and the directly opposite B atom of the carbaborane ligand. The halogen atoms are located almost directly above a C atom in the C₂B₃ face, and the conformations of the [PdX(PR₃)] units above the C₂B₃ faces are not those predicted from molecular orbital calculations of the closo-3,1,2-PdC₂B₉ system. The fact that the variation from the predicted conformation is greater in the case of (I) than in (II) may be ascribed to the greater steric interactions induced by the I atom in (I) compared with the Cl atom in (II)

Autologous Bone Marrow Stem Cells in the Treatment of Chronic Liver Disease

Chronic liver disease (CLD) is increasing worldwide yet there has been no major advance in effective therapies for almost five decades. There is mounting evidence that adult haematopoietic stem cells (HSC) are capable of differentiating into many types of tissue, including skeletal and cardiac muscle, neuronal cells, pneumocytes and hepatocytes. These recent advances in regenerative medicine have brought hope for patients with liver cirrhosis awaiting transplantation. New findings in adult stem cell biology are transforming our understanding of tissue repair raising hopes of successful regenerative hepatology. Although all clinical trials to date have shown some improvement in liver function and CD34(+) cells have been used safely for BM transplantation for over 20 years, only randomised controlled clinical trials will be able to fully assess the potential clinical benefit of adult stem cell therapy for patients with CLD. This article focuses on the potential of bone marrow stem cells (BMSCs) in the management of CLD and the unresolved issues regarding their role. We also outline the different mechanisms by which stem cells may impact on liver disease

[8,8-(PPh3)2-9-(OEt)-8,7-RhSB9H9].0.95(CH2Cl2)

9-Ethoxy-8,8-di(triphenylphosphine)-9,10- tz H-8-rhoda-7-thia-nido-undecaborane( l O) dichloromethane solvate, C38Ha4B9OP2RhS.0.95(CH2C12), Mr = 891.7, triclinic, Pi, a = 10.271 (4), b = 11.401 (3), c = 19.426 (4)/~, a = 74.86 (2), 13 = 88.51 (3), y = 83.51 (3) °, V= 2182 (2)/~3, Z= 2, Dx = 1.357 g cm-3, graphite-monochromated Mo Ka radiation, a = 0.71073 A, /z = 6.5 cm-1, F(000) = 912, T= 294 K, R = 0.038 for 3984 observed reflections. The title compound contains an l 1-atom RhSB9 nido-structured cage with Rh and S atoms adjacent in the open RhSB3 face. An ethoxy group is bonded to the B atom adjacent to Rh in the open face with Rh--B9 2.119 (6) and B9--O 1.387 (9)A. The phosphine ligands are bonded to the Rh atom with one Rh--P bond [2.278 (2)A] trans to the S atom and the other [2.417 (1) A] located perpendicular to the open face of the cage