Vitamin B6 In Ready-To-Eat Cereals: Analysis By High Performance Liquid Chromatography

Twenty-four ready-to-eat cereals obtained locally were analyzed for their vitamin B₆ content by a recently developed high performance liquid chromatographic (HPLC) procedure. The method uses sulfo-salicylic acid as an extraction agent with subsequent qualitative and quantitative analysis by anion exchange chromatography. All six forms of vitamin B₆ plus their metabolite, pyridoxic acid, can be identified and quantified. Spot checks of the results obtained with this method and with a radiometric-microbiological assay give agreement to within 5%. On the other hand, disagreements of up to 38% are found on comparison with the standard AOAC microbiological procedure used by a commercial laboratory. The results indicate no significant variations between boxes within the same lot, but in one-third of the cereals tested, significant variations were found from lot to lot.     

Transfer of antibiotics between the udder quarters of dairy cows treated for clinical mastitis

Milk samples from all quarters of 13 dairy cows, each treated with an antibiotic preparation for clinical mastitis in one quarter, were collected at each milking during treatment and for at least six milkings thereafter. After storage at —25 °C, these were tested for the presence of antibiotics. Transfer to untreated quarters was found in eight of the 13 cases studied, although in only two cases was the level in untreated quarters greater than 0.01 μ/ml. The main factor affecting transfer was found to be a history of infection in the treated quarter. This was observed in all but one case where transfer had occurred. During the period of study incorporation of milk from untreated quarters would not have raised the antibiotic level in the bulk supply to a level which would have incurred a financial penalty.     

The system generator concept for FMS research and analysis

In the research area of FMS, much past work has concentrated upon unique systems analysing production control strategies. In some cases, no physical system was available as reference, necessitating a variety of system assumptions by researchers. It has been very difficult to compare control strategy effectiveness among applications or among researchers due to many different system assumptions and a general lack of standardization among system definitions.

This paper discusses development of a system generator procedure, which would greatly enhance generic control strategy research by allowing rapid generation of test system environments. The basic issues and considerations involved in development of a system generator are discussed. Considering these issues, an implementation of a system generator procedure is presented along with an example of output system representations for given inputs to the generator procedure.     

Physical-Chemical Characteristics of Partially Clarified Guava Juice and Concentrate

Partially clarified guava juice concentrate was prepared from single strength guava puree (5.5°Brix) by treatment with pectinase (2 hr at 50°C), extraction of juice with a rack-and-cloth press, and vacuum concentration to 23°Brix. The concentrate had the following characteristics: density, 1.10; pH, 3.16; total acids, 4.67%; ash, 1.51%; moisture, 72.4%; ascorbic acid, 867 mg%; viscosity, 4.4 cp; and CIE L* 39.2, CIE a* 10.33, CIE b* 27.11.     

SOLUBILITY AND EMULSIFYING PROPERTIES OF BETACASEIN MODIFIED ENZYMATICALLY BY TRYPSIN

Beta A1-casein was treated with TPCK-trypsin to give 3.2, 5.0, 5.8 and 7.4% hydrolysis of the peptide bonds. By sodium dodecyl sulfate-polyacrylamide gel electrophoresis the resulting peptides had apparent molecular weights in the range 8,000–4,000. Size-exclusion chromatography of hydrolyzed samples showed four major peaks near 15,000, 5,500, 3,500 and 2,500 molecular weights, representing 17, 15, 7 and 14% of the material, respectively, after 3.2% hydrolysis and 9, 6, 14 and 52% of the material, respectively, after 7.4% hydrolysis. Between the extremes 3.2% and 7.4% hydrolysis, a peak near 8,500 molecular weight was present until 5.8% hydrolysis then disappeared after 7.4% hydrolysis to be replaced by a peak near 12,000 molecular weight. Peptides recovered from reversed-phase high performance liquid chromatography were analyzed by determination of their amino acid composition and identified in the sequence of β-casein. After trypsin treatment, the solubility of β-casein hydrolysates was largely increased at pH 4.0–7.5. The emulsifying activity of the hydrolysates was higher than that of β-casein in the range of pH 1.5–3.5 and 6.5–10.0, but all the emulsions obtained with trypsin-treated β-casein were less stable than those obtained with original β-casein.     

Chemical Durability of Fluoride Glasses: I, Reaction of Fluorozirconate Glasses with Water

The chemical durability of five flouarozirconate glass compositions was studied. Measurements of leachant composition and solution chemistry by plasma emission spettroscopy, pH, and fluoride analysis are reported. Changes in surface structure were monitored by scanning electron microscopy, electron-probe X-ray analysis, and X-ray diffraction. The modifer additives with high aqueous solubility (A1F₃, NaF, LiF, PbF₂) exhibited the highest leach rates with ZrF₄, BaFs₂, and LaF₃ exhibiting lower rates. The leaching order of Zr > Ba > La was maintained for all samples. The leaching process consists of the dissolution of the glass matrix, leaving a thick and porous layer containing Zr, Ba, La, and molecular water. Hydroxylation of the Zr species to form a hydroxyfluoride complex in solution dominated a decrease in pH to moderately acidic values. The resulting increase in component solubility (particularly zirconium fluoride) in the acidic solutions accelerated the glass dissolution rate and demonstrated that, if no buffer is present to avert the pH drift, the chemical durability of these glasses in aqueous environments is extremely poor, being roughly equivalent to that of Na₂O 2SiO₂.     

Hadrian and the Frontiers of Form

Architecture often stands in its own sculptural right, but how much richer we are to explore its genesis The emperor Hadrian, ruling a kingdom much like our United States in its cultural diversity and strength of influence, realized a design of marvelous paradox in his Villa at Tivoli. This paper seeks to knit together the formal elements of the villa with the human sensibilities of Hadrian by presenting notes from several seminal works, including Mémoires d'Hadrien by Marguerite Yourcenar (Librarie Plon, 1958), and Hadrian's Villa and Its Legacy by William L. MacDonald and John A. Pinto (Yale University Press, 1995).     

The near field of an antenna surrounded by a dielectric with two teeth

The near field of an antenna surrounded by a dielectric with two teeth is studied when the ambient medium is dissipative. We use the continuity of radial power flux and the boundary conditions at each interface, but not near the discontinuity, to express this field.     

Formulations of the capacity planning problem considering manufacturing flexibility

This paper addresses the problem of determining the capacity requirements for a manufacturing system that consists of versatile metal removing machines, each of which may be configured to perform several different operations at varying levels of efficiency and cost. The number of each machine type required and the assignment of each machine type to different processes are determined by minimizing the sum of machine amortization costs and operating costs. Alternative formulations are presented to address non-splitting of a batch and non-splitting of the processing of a part. The formulations are illustrated using numerical examples.