Mathematical Modeling of Encapsulated Buffer Performance in Sand Columns

A one-dimensional mathematical model was developed to simulate pH control using an encapsulated phosphate buffer during denitrification in a sand column. The parameters required for the model were obtained from direct physical measurement, from a tracer study to characterize the dispersion coefficient in the column, and from batch experiments designed to obtain an empirical expression describing the variation of the first-order rate constant for the encapsulated buffer core release with pH. First-order kinetic constants describing the rates of denitrification and ethanol biodegradation were obtained by fitting the model to column runs without the encapsulated buffer. With these parameters, the model was subsequently used to predict the performance of column runs containing the encapsulated buffer. Since denitrification was essentially complete in the sand columns, an increase in the effluent pH was observed. This pH increase was counteracted by the controlled release of the acidic core of the encapsulated buffers added in the columns. The model reasonably predicted the release of the encapsulated buffer core and the performance of the encapsulated buffer for controlling pH in the column.     

Antivitamins for Medicinal Applications

Antivitamins represent a broad class of compounds that counteract the essential effects of vitamins. The symptoms triggered by such antinutritional factors resemble those of vitamin deficiencies, but can be successfully reversed by treating patients with the intact vitamin. Despite being undesirable for healthy organisms, the toxicities of these compounds present considerable interest for biological and medicinal purposes. Indeed, antivitamins played fundamental roles in the development of pioneering antibiotic and antiproliferative drugs, such as prontosil and aminopterin. Their development and optimisation were made possible by the study, throughout the 20th century, of the vitamins' and antivitamins' functions in metabolic processes. However, even with this thorough knowledge, commercialised antivitamin‐based drugs are still nowadays limited to antagonists of vitamins B₉ and K. The antivitamin field thus still needs to be explored more intensely, in view of the outstanding therapeutic success exhibited by several antivitamin‐based medicines. Here we summarise historical achievements and discuss critically recent developments, opportunities and potential limitations of the antivitamin approach, with a special focus on antivitamins K, B₉ and B₁₂.     

Specific factors affecting lead uptake by food from cooking water

Following earlier work, detailed studies have been carried out on the lead uptake of individual foods from soft and hard water containing various amounts of lead. Experiments have also been made to determine whether solutions of lead nitrate in distilled water simulate the behaviour of water containing naturally present lead. The effect of length of cooking time, weight/volume ratio and salt addition have been studied, as well as the depostion of lead on to cooking vessels. In general, green vegetables, carrots, rice and spaghetti were found to take up more lead than do other foods. The difference in uptake observed between hard and soft waters varied according to the particular food being studied. Uptake from lead nitrate solutions showed a very similar pattern to uptake from hard water containing naturally present lead. Equilibrium was reached after only 5 min cooking for cabbage and spaghetti. Varying the solid/volume ratio for cabbage affected the uptake of lead from water, but the addition of sodium chloride or sodium bicarbonate had little effect on lead uptake. There was no sign of saturation in uptake of lead by cabbage from solutions of 11 mg litre^?1 lead as lead nitrate. Deposition of lead occurred on both aluminium and glass saucepans, and cleaning was more effective in removing lead from glass saucepans. Results obtained from the analysis of diets in a small population at Ayr confirmed those obtained previously by laboratory experiments.     

Congruence/genuineness.

Congruence or genuineness is a relational quality that has been highly prized throughout the history of psychotherapy, but of diminished research interest in recent years. In this article, we define and provide examples of this attribute of the therapy relationship and present an original meta-analytic review of the empirical literature showing its relation to improvement. Analysis of 16 studies (k), representing 863 patients (N), resulted in a weighted aggregate ES (r) of .24 (p = .003; 95% CI = .12 to .36). Moderators of the association between congruence and treatment outcome are examined, and limitations of the extant research are discussed as well. In closing, we advance several therapist practices that are likely to foster congruence and thus improve psychotherapy outcomes. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

The effect of anticipatory strategies on the first day of smoking cessation.

The authors tested a model hypothesizing the predictors and the effects of anticipatory strategy use on the 1st day of smoking cessation using data from 63 participants in an ecological momentary assessment study of smoking cessation. Remaining abstinent on the 1st day of cessation was not associated with mean level of urges to smoke during tempting situations but was associated with anticipatory strategy use, which accounted for 18% of the variance. Getting rid of cigarettes contributed the most to this effect (β?=?-.397). Getting rid of cigarettes was itself predicted by 2 variables, lower nicotine dependence (β?=?-.264) and attending a formal smoking cessation class (β?=?.305), which accounted for 15% of its variance. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Development of the First Oral Bioprecursors of Bis‐alkylguanidine Antimalarial Drugs

Plasmodium falciparum is responsible of the most severe form of malaria, and new targets and novel chemotherapeutic scaffolds are needed to fight emerging multidrug‐resistant strains of this parasite. Bis‐alkylguanidines have been designed to mimic choline, resulting in the inhibition of plasmodial de novo phosphatidylcholine biosynthesis. Despite potent in vitro antiplasmodial and in vivo antimalarial activities, a major drawback of these compounds for further clinical development is their low oral bioavailability. To solve this issue, various modulations were performed on bis‐alkylguanidines. The introduction of N‐disubstituents on the guanidino motif improved both in vitro and in vivo activities. On the other hand, in vivo pharmacological evaluation in a mouse model showed that the N‐hydroxylated derivatives constitute the first oral bioprecursors in bis‐alkylguanidine series. This study paves the way for bis‐alkylguanidine‐based oral antimalarial agents targeting plasmodial phospholipid metabolism.     

Simplification of a complex microbial antilisterial consortium to evaluate the contribution of its flora in uncooked pressed cheese

A complex microbial consortium derived from raw milk and composed of populations classified in 4 groups (lactic acid bacteria (A), Gram positive catalase positive bacteria (B), Gram negative bacteria (C) and yeasts (D)) can contribute to the inhibition of Listeria monocytogenes in the core of an uncooked pressed cheese. To identify what groups may be involved in the inhibition, the consortium was simplified by successively omitting one group at a time. Pasteurized milk was inoculated with these more or less complex consortia and their effects on L. monocytogenes count, pH, acids and volatile compounds in the core of uncooked pressed cheese were evaluated. The growth of L. monocytogenes was the highest in cheeses prepared with pasteurized milk and only St. thermophilus. Inhibition in other cheeses was expressed by comparison with growth in these ones. All the consortia containing both lactic acid bacteria (group A) and Gram positive catalase positive bacteria (group B)--ABCD, ABD, ABC, AB--were more inhibitory than those containing lactic acid bacteria on its own (A) or associated only with yeasts (AD) or/and Gram negative (ADC). Consortia without lactic acid bacteria were weakly inhibitory or had no effect. Gram positive catalase positive bacteria alone were not inhibitory although most of the species became established in the cheeses. The Lactobacillus population (Lb. casei, Lb. plantarum, Lb. curvatus and Lb. farciminis) was predominant in cheeses (9 log CFU/g) with a higher count than Leuconostoc (7 log CFU/g) and Enterococcus (7 log CFU/g). Lactobacillus counts were negatively correlated with those of L. monocytogenes (r=-0.84 at 18 days) and with the level of D-lactic acid. There was no correlation between L. monocytogenes and Leuconostoc or Enterococcus counts. Complex consortium ABCD and AB not only had a stronger inhibitory power in cheeses than consortium AD, they were also associated with the highest levels of L-lactic and acetic acids. All cheeses inoculated with lactic acid bacteria differed from those without by higher levels of ethyl formiate, pentane and alcohols (2-butanol, 2-pentanol), and lower levels of ketones (2-hexanone, 2,3-butanedione) and aldehydes (2-methyl-butanal). Levels of 2-methyl-butanal, 2-butanol and 2-pentanol were higher in ABCD and AB cheeses than in AD cheeses. Beside their contribution to the inhibition, their effect on cheese flavour must be evaluated.     

Coping With Downsizing: A Comparison of Executive-Level and Middle Managers.

A longitudinal study compared the reactions of executive-level and middle managers prior to a large-scale downsizing, during initial and final phases, and following the downsizing. Compared with executives, middle managers perceived greater job insecurity, were more likely to use escape coping, and reported lower job performance and higher levels of health symptoms. Over time, both executives and middle managers reported a decline in perceived threat of job loss but an increase in sense of powerlessness, a decrease in the use of control-oriented coping strategies, and reduced job performance in the initial phase of downsizing. Although less so, executive-level managers were also adversely affected by the downsizing, suggesting that this group should be included in stress management interventions. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Development of a psychosocial program on a dialysis unit.

By actively seeking involvement, psychologists were able to develop an intervention program on a dialysis unit. Significant aspects of the program as well as problems encountered are described, and suggestions are made for the application of this approach to other medical settings. (15 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Effect of pre-press treatments of vegetation on the quality of the extracted leaf protein

The effect of various treatments during processing on the quality of extracted leaf protein concentrates from grass and lucerne has been investigated. There was little difference in the N contents of the heat-coagulated leaf proteins from various extracts. The preparations contained only small amounts of extractable phenolic compounds when polyvinylpyrrolidone (PVP) was present during the extraction procedure. Conversely, all leaf proteins made by processes involving treatment with alkali had a larger phenolic content. Some of the phenolic compounds extracted have been tentatively identified. The amino acid composition and in vitro digestibility, with thioglycollic acid-activated papain, of all preparations were similar. These results are discussed in relation to the known in vivo digestibility of extracted leaf protein concentrates.