Analysis Comparative of Methods to Evaluate Consolidation Mechanisms in Plastic and Viscoelastic Materials Used as Direct Compression Excipients

In order to better explain the mechanisms of tablet formation, there is now a greater tendency to investigate particle deformation rather than bulk deformation of the powder bed.

In this sense, measurements of static indentation in tablet to determine compressibility and compactability of powders were used. In this work this method, using as hardness testing a pyramid instead of a ball into the surface of the tablet under test, is compared to Heckel plots using ejected tablet method. Also, bonding index, absolute differences between indentation hardness of tablet surfaces and force-displacement curves were used to establish behaviour of excipients that undergo compression deform plastically and viscoelastic excipients with tendency to deform plastically until applied pressure was exceeded.     

Optimizing surgical backup for multiple simultaneous percutaneous transluminal coronary angioplasty procedures

At busy interventional centers, it may be difficult to coordinate surgical backup for multiple simultaneous PTCA procedures. We sought to determine the actual risk of two simultaneous cases requiring surgery, and to identify a group in which multiple simultaneous PTCA procedures could be performed at low risk. We prospectively applied the ACC/AHA A/B/C lesion classification system and an empiric low/medium/high risk classification (based on patients' overall clinical picture) to 1,128 PTCA procedures over a 9 month period; 22 of these patients (1.9%) went directly from the catheterization laboratory to emergency CABG. The incidence of emergency CABG by groups was A-low 1/166, A-medium 1/71, A-high 0/22, B-low 1/116, B-medium 10/481, B-high 2/52, C-low 2/47, C-medium 3/88, and C-high 2/85. The patients were divided into two groups: minimal risk (A + B-low: 3/375 or 0.8%) and increased risk (B-med/high + C: 19/753 or 2.5%). The difference between the groups was significant using chi square with an alpha < 0.05. The risk of two cases requiring surgery at the same time was calculated as a function of the number of simultaneous PTCA procedures performed. Six or fewer minimal risk PTCA, one increased risk plus up to three minimal risk, and a maximum of two increased risk cases were found to have a risk of < 0.001. We conclude that it is possible to identify a group of patients with minimal risk, in whom multiple simultaneous procedures can be performed with a negligible probability of two cases requiring surgery at the same time.(ABSTRACT TRUNCATED AT 250 WORDS)     

Singularities of sets used in the mesh method

In the paper, sets of nodes leading to singularities in mesh method analysis of problems in mechanics are defined precisely. Forms of singular sets determined by conic curve equations are presented. Examples of such sets are also given.     

Evolution of acid phosphatase activity of honeys from different climates

Acid phosphatase is an enzyme of honey whose values have been related to honey’s fermentation. In this work, we have studied the evolution, throughout thirty months, of acid phosphatase activity on honey samples originating in continental and oceanic areas. We have also researched the influence of induced granulation and pH on acid phosphatase activity evolution. Acid phosphatase activity has been determined by measuring, at 400 nm, 4-nitrophenol formed after the hydrolysis, at acid pH, of 4-nitrophenylphosphate in the presence of acid phosphatase. From the start, acid phosphatase activities have been higher in honeys from oceanic climate. Similar trends of evolution of acid phosphatase activity have been found in both honeys from continental and oceanic climates. In the end of the study, 100% samples showed a decrease of acid phosphatase activity. Induced granulation does not modify the trend of acid phosphatase activity evolution, although this technological process has an influence on the time at which changes within the evolution occurs. pH of samples has demonstrated to have a strong influence on the activity of acid phosphatase, so that the higher the pH, the lower the decrease of acid phosphatase activity. In honeys originated from continental climate area, pH and acid phosphatase activity have been correlated throughout the study.     

Purification and biochemical characterization of chymotrypsin from the viscera of Monterey sardine (Sardinops sagax caeruleus)

Chymotrypsin was isolated from the viscera of Monterey sardine by ammonium sulphate fractionation, gel filtration, and ionic exchange chromatography. The approximate molecular weight was 26,000 and its isoelectric point was about 5. Identity as chymotrypsin was established by its catalytic specificity for amide or ester bonds on the synthetic substrates succinyl-l-ala-ala-pro-l-pheilalanine-p-nitroanilide and benzoyl-l-tyrosine-ethyl-ester, showing esterase activity 3.2-fold higher than amidase. It was inhibited by phenylmethylsulfonyl-fluoride and soybean trypsin inhibitor, partly inhibited by the specific chymotrypsin inhibitor N-toluenesulfonyl-l-phenylalanine chloromethyl-ketone, but not inhibited by EDTA or Benzamidine. Chymotrypsin showed its maximum activity at pH 8.0 and 50 °C for the hydrolysis of SAAPNA. The Michaelis–Menten constant was 0.074 mM with a catalysis constant of 18.6 seg⁻¹, and catalytic efficiency of 252 seg⁻¹ mM⁻¹. Results indicated that Monterey sardine chymotrypsin is a good catalyst and could be used as a biotechnological tool in food processing and using sardine industry wastes as a material for production of fine reagents.     

High temporal, geographic, and income variation in body mass index among adults in Brazil

OBJECTIVES: Population-based data on body mass index for developing countries are scarce. Body mass index data from two Brazilian surveys were examined to determine regional and temporal variations in the prevalences of underweight, overweight, and obesity. METHODS: Nationwide surveys in 1974/75 and 1989 collected anthropometric data in Brazil from 55,000 and 14,455 households, respectively. Trained interviewers used the same methods to measure weight and stature in both surveys, and survey designs were identical. Prevalences of underweight, overweight, and obesity were determined for persons 18 years of age and older. RESULTS: In the 1989 survey, body mass index varied greatly according to region of the country, urbanization, and income. In the wealthier South, the prevalence of overweight/obesity was the highest and the prevalence of underweight was the lowest; in the poorer rural Northeast, these patterns were reversed. For both surveys, overweight/obesity was more common among women than among men and peaked at age 45 to 64 years in both sexes. Over the 15 years between surveys, the prevalence of both overweight and obesity increased strikingly. CONCLUSIONS: In contrast to findings in developed countries, obesity in Brazil was positively associated with income and was much more prevalent among women than among men. For Brazilian women, the overall prevalence of overweight was nearly as high as that among women in the United States.     

Surface phenomena and hydrodynamic effects on the deposition of pseudomonas fluorescens

Biofilm adhesion to metals (copper, aluminium and brass) was studied at two different velocities and pH values of 7 and 9. Both bacteria and metals showed negative surface charges at those values of pH, which tends to slow down adhesion. Film densities increased with the fluid velocity and were also affected by the pH and by the growth rate of the bacteria. Long duration tests based on heat transfer measurements were run at five different fluid velocities and at pH = 7, showing in general an asymptotic behaviour and a control of deposition by adhesion and growth phenomena.