Continuous computer controlled production of formate dehydrogenase (FDH) and isolation on a pilot scale

A continuous production process has been developed up to pilot scale (300 l) for FDH production with the methylotrophic yeast Candida boidinii. A high cell mass specific FDH activity (50 U/g) is achieved by process computer controlled supply of pure methanol to operate the reactor at an optimum methanol concentration of 10 g/l. The maximum FDH spacetime yield achievable with this process control involves a residence time of 7 h. The FDH space-time yield (STY) and FDH concentration are a function of the oxygen transfer rate (OTR) of the fermenter (maximum STY = 255 U/(l h) at k_La = 870 l/h). For a reasonable compromise between high FDH space-time yield and high FDH concentration, an optimum residence time is adjustable by regulating the supply of nutrient salt solution in relation to the OTR of the fermenter. On a pilot scale (200 l continuously stirred tank reactor) roughly 4 million U of FDH were produced within 10 days at a residence time of 14.3 h. Isolation of intracellular FDH enzyme was performed using extraction with an aqueous two-phase system (PEG/K₂HPO₄). A technical product quality of 1.2 U/mg FDH was achieved without any chromatographic purification step.     

Subcooled boiling heat transfer to R 12 in an annular vertical channel

Detailed knowledge of the physical phenomena involved in subcooled boiling is of great importance for the design of liquid-cooled heat generating systems with high heat fluxes. Experimental heat transfer data were obtained for forced convective boiling of dichloro-difluoroethane (R 12). The flow is circulated upwards through a concentric annular vertical channel. The inner and outer diameters of the annulus are 0.016 m and 0.03 m respectively. The reduced pressures studied were 0.24 ≤ p/p_crit ≤ 0.8, inlet subcooling varied from 10 to 75 K and mass fluxes from 500 to 3000 kg/m²s, which corresponds to Re numbers from 30000 to 300000. The experiments, described in this study, demonstrate that liquid fluorocarbons show certain unusual boiling characteristics in the subcooled flow, such as hysteresis of the boiling curve. These characteristics are attributed to the properties of the fluid, mainly the Pr number and the very low surface tension. The pronounced boiling curve hysteresis can be explained by the fact that large nucleation sites may have been flooded prior to incipient boiling. A dimensionless regression formula is presented which predicts the onset of subcooled boiling as a function of reduced pressure (p/p_crit), Boiling-(Bo), Reynolds-(Re), and a modified Jacob number (Ja), over the whole range of parameters studied, with a good accuracy, including water data from literature.     

Der Einfluß enzymatischer Behandlungen auf die Tränkbarkeit k;einer Fichtenproben

The permeability of spruce wood (Picea abies L. Karst) was considerably improved by pretreatment with enzymes. Sapwood was improved to greater extent than heartwood. The most succesful were commercial preparations of cellulase, hemicellulase and pectinase mixtures. Different concentrations, buffers and temperature ranges were tested. The best results were reached with 1% suspensions in buffer at 25–40 “C.     

Minor Fields of Undergraduate Majors in Psychology.

Undergraduate majors in psychology are admonished to select strong supporting minors such as biology or mathematics. Journal articles remark about the desirability of such supporting minors, and association meetings schedule programs to consider the relative merits of various minor fields. But, at least since 1948, no study has been reported to indicate which subject areas are actually selected for minors. It is the concern of the present report of show the distribution of these minors as reported in the official graduation records in a state university over a 15-year period. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Emotional behavior in feral cats with ablations of prefrontal cortex and subsequent lesions in amygdala.

Bilateral ablations of gyrus proreus in 6 cats did not significantly alter either the intensity or the pattern of flight behavior during confrontation with a human. The scores for defense behavior were reduced in only 2 Ss. Subsequent lesions in the rostral part of the basolateral nuclei of amygdala reduced flight and transiently decreased defense scores in all Ss. It is concluded that the prefrontal cortex does not seem necessary for the flight and defense responding observed in feral cats. The role of amygdala in the regulation of these behaviors is confirmed. (26 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Corticosterone and avoidance in rats with basolateral amygdala lesions.

Produced deficient acquisition of 2-way active and passive avoidance in 15 male Moll-Wistar rats after bilateral electrolytic lesions restricted to the dorsal part of the basolateral nuclei. Other deficits also suggest a general reduction in fear or arousal: less immobility in the open field and during active-avoidance intertrial intervals, and slower escape latencies and less pituitary-adrenal activation during the initial active-avoidance session. Anatomical analysis of the areas producing the greatest deficit suggests that differential involvement of the insula may explain phylogenetic differences between these data from the rat and previous data from the cat, which show only active-avoidance deficiency after basolateral lesions. (26 ref.) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Shannon optimal priors on independent identically distributed statistical experiments converge weakly to Jeffreys' prior

In 1979, J.M. Bernardo argued heuristically that in the case of regular product experiments his information theoretic reference prior is equal to Jeffreys' prior. In this context, B.S. Clarke and A.R. Barron showed in 1994, that in the same class of experiments Jeffreys' prior is asymptotically optimal in the sense of Shannon, or, in Bayesian terms, Jeffreys' prior is asymptotically least favorable under Kullback Leibler risk. In the present paper, we prove, based on Clarke and Barron's results, that every sequence of Shannon optimal priors on a sequence of regular iid product experiments converges weakly to Jeffreys' prior. This means that for increasing sample size Kullback Leibler least favorable priors tend to Jeffreys' prior.