Predicting the thermal inactivation of bacteria in a solid matrix: simulation studies on the relative effects of microbial thermal resistance parameters and process conditions

A combined mathematical model for predicting heat penetration and microbial inactivation in a solid body heated by conduction was tested experimentally by inoculating agar cylinders with Salmonella typhimurium or Enterococcus faecium and heating in a water bath. Regions of growth where bacteria had survived after heating were measured by image analysis and compared with model predictions. Visualisation of the regions of growth was improved by incorporating chromogenic metabolic indicators into the agar. Preliminary tests established that the model performed satisfactorily with both test organisms and with cylinders of different diameter. The model was then used in simulation studies in which the parameters D, z, inoculum size, cylinder diameter and heating temperature were systematically varied. These simulations showed that the biological variables D, z and inoculum size had a relatively small effect on the time needed to eliminate bacteria at the cylinder axis in comparison with the physical variables heating temperature and cylinder diameter, which had a much greater relative effect. (c) 2005 Elsevier B.V All rights reserved.

Cognitive tests used in chronic adult human randomised controlled trial micronutrient and phytochemical intervention studies

In recent years there has been a rapid growth of interest in exploring the relationship between nutritional therapies and the maintenance of cognitive function in adulthood. Emerging evidence reveals an increasingly complex picture with respect to the benefits of various food constituents on learning, memory and psychomotor function in adults. However, to date, there has been little consensus in human studies on the range of cognitive domains to be tested or the particular tests to be employed. To illustrate the potential difficulties that this poses, we conducted a systematic review of existing human adult randomised controlled trial (RCT) studies that have investigated the effects of 24 d to 36 months of supplementation with flavonoids and micronutrients on cognitive performance. There were thirty-nine studies employing a total of 121 different cognitive tasks that met the criteria for inclusion. Results showed that less than half of these studies reported positive effects of treatment, with some important cognitive domains either under-represented or not explored at all. Although there was some evidence of sensitivity to nutritional supplementation in a number of domains (for example, executive function, spatial working memory), interpretation is currently difficult given the prevailing 'scattergun approach' for selecting cognitive tests. Specifically, the practice means that it is often difficult to distinguish between a boundary condition for a particular nutrient and a lack of task sensitivity. We argue that for significant future progress to be made, researchers need to pay much closer attention to existing human RCT and animal data, as well as to more basic issues surrounding task sensitivity, statistical power and type I error.

Predicting fatty acid profiles in blood based on food intake and the FADS1 rs174546 SNP

SCOPE: A high intake of n-3 PUFA provides health benefits via changes in the n-6/n-3 ratio in blood. In addition to such dietary PUFAs, variants in the fatty acid desaturase 1 (FADS1) gene are also associated with altered PUFA profiles. METHODS AND RESULTS: We used mathematical modelling to predict levels of PUFA in whole blood, based on MHT and bolasso selected food items, anthropometric and lifestyle factors, and the rs174546 genotypes in FADS1 from 1,607 participants (Food4Me Study). The models were developed using data from the first reported time point (training set) and their predictive power was evaluated using data from the last reported time point (test set). Amongst other food items, fish, pizza, chicken and cereals were identified as being associated with the PUFA profiles. Using these food items and the rs174546 genotypes as predictors, models explained 26% to 43% of the variability in PUFA concentrations in the training set and 22% to 33% in the test set. CONCLUSIONS: Selecting food items using MHT is a valuable contribution to determine predictors, as our models' predictive power is higher compared to analogue studies. As unique feature, we additionally confirmed our models' power based on a test set.

Closed-loop feedback computation model of dynamical reputation based on the local trust evaluation in business-to-consumer e-commerce

Trust and reputation are important factors that influence the success of both traditional transactions in physical social networks and modern e-commerce in virtual Internet environments. It is difficult to define the concept of trust and quantify it because trust has both subjective and objective characteristics at the same time. A well-reported issue with reputation management system in business-to-consumer (BtoC) e-commerce is the “all good reputation” problem. In order to deal with the confusion, a new computational model of reputation is proposed in this paper. The ratings of each customer are set as basic trust score events. In addition, the time series of massive ratings are aggregated to formulate the sellers’ local temporal trust scores by Beta distribution. A logical model of trust and reputation is established based on the analysis of the dynamical relationship between trust and reputation. As for single goods with repeat transactions, an iterative mathematical model of trust and reputation is established with a closed-loop feedback mechanism. Numerical experiments on repeated transactions recorded over a period of 24 months are performed. The experimental results show that the proposed method plays guiding roles for both theoretical research into trust and reputation and the practical design of reputation systems in BtoC e-commerce.

Pooled analysis of recent studies on magnetic fields and childhood leukaemia

BACKGROUND: Previous pooled analyses have reported an association between magnetic fields and childhood leukaemia. We present a pooled analysis based on primary data from studies on residential magnetic fields and childhood leukaemia published after 2000. METHODS: Seven studies with a total of 10 865 cases and 12 853 controls were included. The main analysis focused on 24-h magnetic field measurements or calculated fields in residences. RESULTS: In the combined results, risk increased with increase in exposure, but the estimates were imprecise. The odds ratios for exposure categories of 0.1-0.2 mu T, 0.2-0.3 mu T and >= 0.3 mu T, compared with <0.1 mu T, were 1.07 (95% Cl 0.81-1.41), 1.16 (0.69-1.93) and 1.44 (0.88-2.36), respectively. Without the most influential study from Brazil, the odds ratios increased somewhat. An increasing trend was also suggested by a nonparametric analysis conducted using a generalised additive model. CONCLUSIONS: Our results are in line with previous pooled analyses showing an association between magnetic fields and childhood leukaemia. Overall, the association is weaker in the most recently conducted studies, but these studies are small and lack methodological improvements needed to resolve the apparent association. We conclude that recent studies on magnetic fields and childhood leukaemia do not alter the previous assessment that magnetic fields are possibly carcinogenic. British Journal of Cancer (2010) 103, 1128-1135. doi: 10.1038/sj.bjc.6605838 www.bjcancer.com (c) 2010 Cancer Research UK

TL, OSL and ESR studies on beryllium oxide

Electron spin resonance (ESR) studies were carried out to identify the defect centres responsible for the thermoluminescence (TL) and optically stimulated luminescence (OSL) processes in BeO phosphor. Two defect centres were identified in irradiated BeO phosphor by ESR measurements, which were carried out at room temperature and these were assigned to an O(-) ion and Al(2+) centre. The O(-) ion (hole centre) correlates with the main 190 degrees C TL peak. The Al(2+) centre (electron centre), which acts as a recombination centre, also correlates to the 190 degrees C TL peak. A third centre, observed during thermal annealing studies, is assigned to an O(-) ion and is related to the high temperature TL at 317 degrees C. This centre also appears to be responsible for the observed OSL process in BeO phosphor. (c) 2010 Elsevier B.V. All rights reserved.

Fragment-Based QSAR and Molecular Modeling Studies on a Series of Discodermolide Analogs as Microtubule-Stabilizing Anticancer Agents

Inhibition of microtubule function is an attractive rational approach to anticancer therapy. Although taxanes are the most prominent among the microtubule-stabilizers, their clinical toxicity, poor pharmacokinetic properties, and resistance have stimulated the search for new antitumor agents having the same mechanism of action. Discodermolide is an example of nontaxane natural product that has the same mechanism of action, demonstrating superior antitumor efficacy and therapeutic index. The extraordinary chemical and biological properties have qualified discodermolide as a lead structure for the design of novel anticancer agents with optimized therapeutic properties. In the present work, we have employed a specialized fragment-based method to develop robust quantitative structure - activity relationship models for a series of synthetic discodermolide analogs. The generated molecular recognition patterns were combined with three-dimensional molecular modeling studies as a fundamental step on the path to understanding the molecular basis of drug-receptor interactions within this important series of potent antitumoral agents.

'Moving On' and Transitional Bridges : Studies on migration, violence and wellbeing in encounters with Somali-born women and the maternity health care in Sweden

During the latest decade Somali-born women with experiences of long-lasting war followed by migration have increasingly encountered Swedish maternity care, where antenatal care midwives are assigned to ask questions about exposure to violence. The overall aim in this thesis was to gain deeper understanding of Somali-born women’s wellbeing and needs during the parallel transitions of migration to Sweden and childbearing, focusing on maternity healthcare encounters and violence. Data were obtained from medical records (paper I), qualitative interviews with Somali-born women (II, III) and Swedish antenatal care midwives (IV). Descriptive statistics and thematic analysis were used. Compared to pregnancies of Swedish-born women, Somali-born women’s pregnancies demonstrated later booking and less visits to antenatal care, more maternal morbidity but less psychiatric treatment, less medical pain relief during delivery and more emergency caesarean sections and small-for-gestational-age infants (I). Political violence with broken societal structures before migration contributed to up-rootedness, limited healthcare and absent state-based support to women subjected to violence, which reinforced reliance on social networks, own endurance and faith in Somalia (II). After migration, sources of wellbeing were a pragmatic “moving-on” approach including faith and motherhood, combined with social coherence. Lawful rights for women were appreciated but could concurrently risk creating power tensions in partner relationships. Generally, the Somali-born women associated the midwife more with providing medical care than with overall wellbeing or concerns about violence, but new societal resources were parallel incorporated with known resources (III). Midwives strived for woman-centered approaches beyond ethnicity and culture in care encounters, with language, social gaps and divergent views on violence as potential barriers in violence inquiry. Somali-born women’s strength and contentment were highlighted, and ongoing violence seldom encountered according to the midwives experiences (IV). Pragmatism including “moving on” combined with support from family and social networks, indicate capability to cope with violence and migration-related stress. However, this must be balanced against potential unspoken needs at individual level in care encounters.With trustful relationships, optimized interaction and networking with local Somali communities and across professions, the antenatal midwife can have a “bridging-function” in balancing between dual societies and contribute to healthy transitions in the new society.

Studies on the cooling minimum quantity and conventional cooling at hardened steels in grinding process

The purpose of this work is to explain the concept of cutting fluids reasonable usage through the fluid minimum quantity in grinding processes. on that purpose, the development of a new nozzle and an own and adequate methodology should be required in order to obtain good results and compare them to the conventional methods. The analysis of the grinding wheel/cutting fluid performance was accomplished from the following input parameters: flow rate variation by nozzle diameter changes (three diameters values: 3mm, 4mm and 5mm), besides the conventional round nozzle already within the machine. Integral oil and a synthetic emulsion were used as cutting fluids and a conventional grinding wheel was employed. The workpieces were made of steel VC 131, tempered and quenched with 60HRc. Thus, as the flow rate and the nozzle diameter changes, keeping steady fluid jet velocity (equal to cutting velocity), attempted to find the best machining conditions, with the purpose to obtain a decrease on the cutting fluid volume, taking into consideration the analysis of the process output variables such as cutting strength, cutting specific energy, grinding wheel wear and surface roughness. It was verified that the 3mm diameter optimized nozzle and the integral oil, in general, was the best combination among all proposed.

Evaluation of mammographic density and Tc-99m-sestamibi scintimammographic uptake in postmenopausal women on hormone replacement therapy

Objective: To evaluate changes in mammographic density and Tc-99m-sestamibi scintimammographic uptake in postmenopausal women on hormone replacement therapy (HRT).Methods: Seventy-five postmenopausal women were prospectively studied and allocated into three groups: 50 women were randomized to either Group 1 (G1, n = 25), which received 2 mg of 17 beta-oestradiol continuously combined with 1 mg of norethisterone acetate (E-2/NETA, Kliogest (R), Medley) or Group 2 (G2), which received 2.5 mg/day of tibolone (Livial (R), Organon). The remaining 25 women, who were asymptomatic and had no desire to undergo HRT, constituted the control group (G3). Each patient was submitted to both mammography and scintimammography at baseline and after six months. Mammographic density was evaluated by using the BI-RADS classification system. The classification system of Barros et al. was used in the interpretation of scintimammography. For statistical analysis, the Chi-square test, ANOVA and Pearson's correlation were used.Results: At six months, increased mammographic density was observed in 48% of G1, 12% of G2 and 16% of G3 patients (p < 0.001). The increase in sestamibi uptake was 56% in G1, 28% in G2 and 24% in G3 (p < 0.001). Increases in both density and uptake were significantly higher in the group on E-2/NETA than among tibolone users and the controls.Conclusion: In postmenopausal women, HRT with E-2/NETA was associated with increased mammographic density and increased Tc-99m-sestamibi scintimammographic uptakes, suggesting greater mithochondrial activity in the cells of the mammary duct. This was not observed in users of 2.5 mg of tibolone, demonstrating that the effects on the breast were reduced. The same was observed in the control group. (c) 2005 Elsevier B.V.. All rights reserved.

Studies on anti-allergic constituents in the leaves and stems of Anchietia salutaris var. martiana (Violaceae)

The anti-allergic active fractionation of hexane extracts of the leaves and stems of Anchietia salutaris,ar. martiana (family Violaceae) nas performed by monitoring their activities with an in vitro bioassay system measuring the inhibitory effects on induced histamine release from guinea pig lung cells. Three known pentacyclic triterpenes (friedelin, alpha-amyrin, beta-amyrin) were isolated, but these compounds were inactive. Aliphatic hydrocarbons and methyl esters of fatty acids (palmitic, oleic, linoleic, linolenic acids) were detected in active fractions. All compounds isolated were detected for the first time in this medicinal plant.

STUDIES ON THE RELATIONSHIP BETWEEN THE PATHOGENICITY OF PARACOCCIDIOIDES-BRASILIENSIS IN MICE AND ITS GROWTH-RATE UNDER DIFFERENT OXYGEN ATMOSPHERES

We performed comparative studies of the pathogenicity of six strains of Paracoccidioides brasiliensis (Bt-9, Bt-4, Pb-9, Pb-18, Bt-7 and B-1183) for young adult male ddY mice and growth rate of each strain under different oxygen atmospheres (aerobic, micro-aerobic and anaerobic atmospheres) at 37-degrees-C. 10(6) units of yeast cells were intravenously injected into each mouse. The pathogenicity of each isolate was determined by a scoring system based on organ culture and histopathological findings. The growth rates under different oxygen atmospheres were determined by a scoring system in which 300 fungal units per strain were counted. The strain Bt-9 showed the greatest pathogenicity, followed by Bt-4. Pb-9 and Pb-18 had on intermediate rank of pathogenicity. Bt-7 and B-1183 were the least pathogenic of the strains tested. Except for strain Bt-7 all strains showed an excellent growth under an aerobic atmosphere. Bt-4 and Bt-9 also showed excellent growth under a micro-aerobic atmosphere, followed by Pb-9, whereas the growth of Pb-18, Bt-7 and B-1183 was limited. There was a correlation between the growth rate under a micro-aerobic atmosphere and the pathogenicity of a strain. The growth rate of P. brasiliensis under a micro-aerobic atmosphere strongly correlated to its pathogenicity.

Denervation supersensitivity to phenylephrine in guinea-pig vas deferens in vivo and in vitro - Functional studies on alpha(1)-adrenoceptors

The objective was to estimate alterations in adrenergic receptor sites of guinea pig vas deferens, in vivo and in vitro, induced by chronic denervation. The denervation process induced an increased sensitivity (3-fold at the EC50 level) without alteration in the maximum response to phenylephrine in vitro. The sensitivity alteration was characterized by the decrease in the dissociation constant of phenylephrine for alpha-adrenoceptor [K-A: normal tissue 3.50 (0.75-16.21) x 10(-5) and denervated tissue 0.43 (0.11-1.67) x 10(-5) M, p < 0.05] without changing the dissociation constant of prazosin. A decrease in pD(2)' value for phenylephrine-phenoxybenzamine, probably due to a qualitative rather than a quantitative alteration in the alpha-adrenoceptor, was also shown in vitro [pD(2)': normal tissue (8.2776 +/- 0.0402) and denervated tissue (8.0051 +/- 0.0442), p < 0.05]. No change in sensitivity and maximum response to phenylephrine was observed in vivo after denervation, although an increased resistance of vas deferens to phenoxybenzamine blockade has been evidenced in this condition. (C) 1999 Elsevier B.V. All rights reserved.

Synthesis and X-ray structure of the dinuclear platinum(II) complex with saccharin {K[Pt(sac)(3)(H2O)] center dot H2O}(2): Studies on its antiproliferative activity in aqueous solution

Synthesis and X-ray structure of a dinuclear platinum(II) complex with the ligand saccharin(sac) are described. The structure shows two approximately square-planar platinum centers. Each platinum atom is coordinated to one water molecule and three N-bonded saccharinate ligands. The two centers are linked through two potassium atoms. Each potassium atom interacts with six oxygen atoms from hydration and coordinated water molecules and from carbonyl and sulfonate groups of the ligands. It is suggested that, in aqueous solution, the dimeric structure of the complex is dissociated and the monomeric species K[Pt(sac)(3)(H2O)] is formed. The complex was dissolved in water and submitted to in vitro cytotoxic analyses using HeLa cells (human cervix cancer). It was shown that the monomeric complex elicited a potent cytotoxic activity when compared to the vehicle-treated cells. The IC50 value for the monomeric complex is 6.8 mu M, a little bit higher than that obtained for cisplatin. (c) 2007 Elsevier B.V. All rights reserved.