Effects of Heat Treatments on the Ethylene Forming Enzyme System in Papayas

Heat inactivation studies were conducted on the ethylene-forming enzyme system (EFE) in papayas. Heat inactivation of the papaya EFE was biphasic and both phases followed first order kinetics. The activation energies E, for the thermal inactivation of the heat resistant (HR) and the heat susceptible (HS) EFEs were 68.3 and 51.2 Kcal/ mole, respectively. The thermodynamic constants for the heat inactivation of both EFEs were; enthalapy, 5 1.2 kcal/mole for HS and 66.7 kcal/mole for HR; free energy, 22.5 kcal/mole for HS and 23.3 kcal/mole for HR; entropy, 87.2 cal/deg-mole for HS and 137.8 call degmole for HR. The heat resistant EFE appeared to compromise about 25% of the total EFE activity. Commercial heat treatments used for quarantine treatments affected mainly the heat susceptible portion which comprised the remaining 75% of the total EFE activity.     

Color Centers and Point Defects in Irradiated Thoria

The optical absorbance of commercially pure thoria single crystals was measured after oxidizing and reducing treatments, irradiation by 18-MeV protons, 48-MeV ¹⁶O ions, and ⁶⁰Co gamma photons, and thermal annealing at temperatures up to 950° C. For unirradiated specimens, absorption bands previously observed at 2.80, 3.03, and 4.03 eV were confirmed, and additional bands were identified at 1.67, 2.04, 2.45, 3.61, and 4.52 eV. Reduction and irradiation enhanced the 3.03 and 3.61 eV bands but diminished the 2.80, 4.03, and 4.52 eV bands. The centers responsible for the two groups of bands are thus presumed to be electron-type and hole-type, respectively. Impurity atoms, also, are probably involved in the centers. Ion irradiation produced an intense blue color in the exposed volume of the specimens, and additional absorption bands appeared at 1.49, 1.80, 2.03, and 2.32 eV. The behavior of these bands on annealing and on subsequent low-exposure gamma irradiation indicated that the corresponding centers are combinations of impurity atoms and oxygen interstitials.     

PREDICTION OF ADULT PSYCHOLOGICAL HEALTH IN A LONGITUDINAL STUDY.

PSYCHOLOGICAL HEALTH IN YOUNG ADULTHOOD WAS PREDICTED FROM PERSONALITY EVALUATIONS THROUGHOUT DEVELOPMENT IN A LONGITUDINAL SAMPLE OF 31 MEN AND 33 WOMEN. CLUSTERS OF BEHAVIORALLY DEFINED RATINGS OF OVER 30 PERSONALITY CHARACTERISTICS, SPANNING THE AGES OF 5-16 YR., WERE DERIVED SEPARATELY FOR EACH SEX. ADULT HEALTH WAS DEFINED BY THE CORRELATION OF A COMPOSITE Q-SORT DESCRIPTION OF EACH S (BASED ON THE ADULT ASSESSMENT MATERIAL), WITH A STANDARD Q SORT BASED ON A HYPOTHETICAL PSYCHOLOGICALLY HEALTHY ADULT. 4 DEVELOPMENTAL PERIODS WERE USED; ONLY 1 (AGES 11, 12, AND 13) HAD SIGNIFICANT MULTIPLE CORRELATIONS WITH ADULT HEALTH. THIS HELD TRUE FOR BOTH SEXES ALTHOUGH THE SPECIFIC PREDICTORS DIFFERED FOR MEN AND WOMEN. (18 REF.) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Papaya Polygalacturonase and its Role in Thermally Injured Ripening Fruit

The polygalacturonase (E.C. 3.2.1.15) (PGase) activity in papayas increased with fruit ripeness. PGase activity was highest in the placenta with the activity decreasing outwardly from the placenta to the exocarp. Extended hot water treatments (46°C for 65 and 90 min) caused delayed softening of the fruit tissue which was correlated to a decrease in PGase activity. The decrease in PGase activity after the heat treatments was more severe in the riper fruits (quarter and half ripe) than the less ripe fruits (colorbreak stage).     

Partial Purification and Characterization of an Acid Phosphatase from Papaya

A phosphatase in papaya was extracted, partially purified, and characterized. With p-nitrophenyl phosphate as substrate, the enzyme had a pH optimum of 6.0, which categorized it as an acid phosphatase, a temperature optimum of 37°C, and a Km of 1.0 mM. Heat inactivation of papaya acid phosphatase was biphasic, and the kinetics of both phases were first order reactions. D values at 60°, 65°, 70°C for the heat resistant phase were 21.0, 11.7, and 4.0 min, respectively. For the heat labile and heat resistant isozymes of papaya acid phosphatase, the activation energies, E_a, for thermal inactivation were 60.0 Kcal/mole and 37.8 Kcal/mole, respectively. The apparent molecular weight of the enzyme as determined by gel filtration was 120,000 daltons.     

Optical Absorption Spectroscopy of ThO2

The optical absorption spectra from 200 to 2700 nm were determined for arc-fused ThO₂ crystals of much higher purity than any available hitherto. The fundamental absorption edge for these crystals lies at a much higher energy (∼5.9 eV) than the apparent edge reported previously for less pure specimens. This apparent edge is shown to result from one or more prominent high-energy absorption bands superimposed on the true edge for such specimens. By comparing the spectra for different specimens subjected to thermal and γ-irradiation treatments, 31 distinct absorption bands were revealed in the ThO₂ spectrum. A full analysis of certain crystals by spark-source mass spectrometry gave no strong correlation between specific band areas and individual impurity-element concentrations. Most of the bands, however, are believed to be associated with the impurity content.     

Transmission Electron Microscopy of Boundary-Lubricated Bearing Surfaces. Part II: Mineral Oil Lubricant with Sulfur-and Phosphorus-Containing Gear Oil Additives

Transmission electron microscopy (TEM) was performed on cross-sectional samples of tapered roller bearing cone surfaces that were tested at two levels of local boundary lubrication severity, Λ ～ 1.1 and 0.3. Unlike our previously reported work in which a base mineral oil was used, the bearing tests were conducted in mineral oil with sulfur- and phosphorus-containing gear oil additives. Structural and compositional characterization of undetached antiwear surface layers on the base steel (cone raceway) revealed that the films contained crystalline and amorphous regions. A sharp interface (<～10 nm) that separated the surface layer and base steel was imaged. The surface layer for the cone tested at Λ ～ 1.1 consisted of Fe, O, and P, whereas that for the cone tested at Λ ～ 0.3 consisted of Fe, O, P, C, Ca, and S. Various TEM analytical techniques were used to study the segregation of these elements throughout the antiwear surface layer volume.