This study examines the ability of P450cam to catalyze the formation of 2-ethylhexanoic acid from 2-ethylhexanol relative to its activity on the natural substrate camphor. As is the case for camphor, the P450cam exhibits stereoselectivity for binding (R)- and (S)-2-ethylhexanol. Kinetic studies indicate (R)-2-ethylhexanoic acid is produced 3.5 times as fast as the (S)-enantiomer. In a racemic mixture of 2-ethylhexanol, P450cam produces 50% more (R)-2-ethylhexanoic acid than (S)-2-ethylhexanoic acid. The reason for stereoselective 2-ethylhexanoic acid production is seen in regioselectivity assays, where (R)-2-ethylhexanoic acid comprises 50% of total products while (S)-2-ethylhexanoic acid comprises only 13%. (R)- and (S)-2-ethylhexanol exhibit similar characteristics with respect to the amount of oxygen and reducing equivalents consumed, however, with (S)-2-ethylhexanol turnover producing more water than the (R)-enantiomer. Crystallographic studies of P450cam with (R)- or (S)-2-ethylhexanoic acid suggest that the (R)-enantiomer binds in a more ordered state. These results indicate that wild-type P450cam displays stereoselectivity toward 2-ethylhexanoic acid synthesis, providing a platform for rational active site design.

Certain fractures and/or dislocations of the femoral head are known to cause arterial injury and result in post-traumatic osteonecrosis. However, the more complex etiology of non-traumatic osteonecrosis is multifactorial and includes chemotherapy, radiotherapy, thermal injuries, and especially coagulopathies, which are now commonly observed in these patients. Intravascular coagulation with fibrin thrombosis begins in the capillaries and sinusoids of the intraosseous microcirculation, and residual venous thrombosis is more likely to occur if there is coexistent hypofibrinolysis. Coagulopathies are intermediary events, which are always activated by some underlying etiologic risk factor(s). Conditions capable of triggering intravascular coagulation include familial thrombophilia (resistance to activated protein C, decreased protein C, protein S, or antithrombin III, and hyperhomocystinemia), hyperlipemia and embolic lipid (alcoholism and hypercortisonism), hypersensitivity reactions (allograft organ rejection, immune complexes, and antiphospholipid antibodies), bacterial endotoxic (Shwartzman) reactions and various viral infections, proteolytic enzymes (pancreatitis), tissue factor release (inflammatory bowel disease, malignancies, neurotrauma, and pregnancy), and other thrombophilic and hypofibrinolytic disorders. Currently known risk factors for non-traumatic osteonecrosis of the femoral head are described briefly in this review article.

It is demonstrated that an AT-cut quartz crystal driven in the thickness-shear-wave mode and typically used as a sensor to monitor the viscoelastic shear-wave properties of a fluid also produce longitudinal pressure waves. Unlike the shear wave, these waves are capable of long-range propagation through the fluid and of reflection at its boundaries, notably at an outer fluid-air interface. They introduce a component into the measured electrical impedance and resonance frequency shift of the crystal, which reflects the setting up of cyclic pressure-wave resonances in the fluid. This has important implications for the practical employment of these crystal as sensors. Under appropriate conditions, as demonstrated for water and n-octane, it is possible to determine the propagating properties of sound waves in a fluid simultaneously with the viscoelastic shear-wave properties. These experiments are supported by an analysis of the appropriate hydrodynamic equations for waves in the crystal-fluid system, which predicts electrical characteristics in close agreement with those found experimentally.

The direct electrochemistry of the flavin-containing monooxygenase, pentachlorophenol hydroxylase (PCPH), at an edge plane graphite electrode was observed and a catalytic response, linear with concentration, was found with the substrate pentachlorophenol (PCP).

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