Home About us Contact
|
Home About us Contact | ||
|
|
||
Studied Parameters (studied + parameter)
Selected AbstractsMODELING OF TEXTURE EVOLUTION OF CAKES DURING STORAGEJOURNAL OF TEXTURE STUDIES, Issue 1 2010MANUEL GÓMEZ ABSTRACT The aim of this work is to model the variation of texture parameters in cakes during staling. The evolution was studied in layer cakes (cake A) and sponge cakes (cake B). The effect of storage temperature and the addition of fiber, xanthan gum (cake A) and emulsifier (cake B) were also studied. The best model to adjust the texture parameters variation during storage in both kinds of cakes was square root x (y = a + b * x1/2), except for firmness and springiness in cakes B. Firmness and springiness were adjusted the best to the linear model. In the model, y stood for the textural parameters and x for the time. a and b were related to the initial value of the studied parameter and with its change over time respectively. In both kinds of cakes, A and B, the firmness and gumminess increased, and the cohesiveness, springiness and resilience decreased, as the storage time increased. The increase in the storage temperature and the addition of fiber minimized the firmness changes in both kinds of cakes. PRACTICAL APPLICATIONS This methodology simplifies the study of cake textural parameters during storage and the result interpretation. Moreover, the correlation analysis has demonstrated that the number of textural parameters of cakes to study can be reduced. [source] Sedimentological, modal analysis and geochemical studies of desert and coastal dunes, Altar Desert, NW MexicoEARTH SURFACE PROCESSES AND LANDFORMS, Issue 4 2007J. J. Kasper-Zubillaga Abstract Sedimentological, compositional and geochemical determinations were carried out on 54 desert and coastal dune sand samples to study the provenance of desert and coastal dunes of the Altar Desert, Sonora, Mexico. Grain size distributions of the desert dune sands are influenced by the Colorado River Delta sediment supply and wind selectiveness. The desert dune sands are derived mainly from the quartz-rich Colorado River Delta sediments and sedimentary lithics. The dune height does not exert a control over the grain size distributions of the desert dune sands. The quartz enrichment of the desert dune sands may be due to wind sorting, which concentrates more quartz grains, and to the aeolian activity, which has depleted the feldspar grains through subaerial collisions. The desert dune sands suffer from little chemical weathering and they are chemically homogeneous, with chemical alteration indices similar to those found in other deserts of the world. The desert sands have been more influenced by sedimentary and granitic sources. This is supported by the fact that Ba and Sr concentration values of the desert sands are within the range of the Ba and Sr concentration values of the Colorado River quartz-rich sediments. The Sr values are also linked to the presence of Ca-bearing minerals. The Zr values are linked to the sedimentary sources and heavy mineral content in the desert dunes. The Golfo de Santa Clara and Puerto Peñasco coastal dune sands are influenced by long shore drift, tidal and aeolian processes. Coarse grains are found on the flanks whereas fine grains are on the crest of the dunes. High tidal regimens, long shore drift and supply from Colorado Delta River sediments produce quartz-rich sands on the beach that are subsequently transported into the coastal dunes. Outcrops of Quaternary sedimentary rocks and granitic sources increase the sedimentary and plutonic lithic content of the coastal dune sands. The chemical index of alteration (CIA) values for the desert and coastal dune sands indicate that both dune types are chemically homogeneous. The trace element values for the coastal dune sands are similar to those found for the desert dune sands. However, an increase in Sr content in the coastal dune sands may be due to more CaCO3 of biogenic origin as compared to the desert dune sands. Correlations between the studied parameters show that the dune sands are controlled by sedimentary sources (e.g. Colorado River Delta sediments), since heavy minerals are present in low percentages in the dune sands, probably due to little heavy mineral content from the source sediment; grain sizes in the dune sands are coarser than those in which heavy minerals are found and/or the wind speed might not exert a potential entrainment effect on the heavy mineral fractions to be transported into the dune. A cluster analysis shows that the El Pinacate group is significantly different from the rest of the dune sands in terms of the grain-size parameters due to longer transport of the sands and the long distance from the source sediment, whereas the Puerto Peñasco coastal dune sands are different from the rest of the groups in terms of their geochemistry, probably caused by their high CaCO3 content and slight decrease in the CIA value. Copyright © 2006 John Wiley & Sons, Ltd. [source] Transient thermal modelling of heat recovery steam generators in combined cycle power plantsINTERNATIONAL JOURNAL OF ENERGY RESEARCH, Issue 11 2007Sepehr Sanaye Abstract Heat recovery steam generator (HRSG) is a major component of a combined cycle power plant (CCPP). This equipment is particularly subject to severe thermal stress especially during cold start-up period. Hence, it is important to predict the operational parameters of HRSGs such as temperature of steam, water, hot gas and tube metal of heating elements as well as pressure change in drums during transient and steady-state operation. These parameters may be used for estimating thermal and mechanical stresses which are important in HRSG design and operation. In this paper, the results of a developed thermal model for predicting the working conditions of HRSG elements during transient and steady-state operations are reported. The model is capable of analysing arbitrary number of pressure levels and any number of elements such as superheater, evaporator, economizer, deaerator, desuperheater, reheater, as well as duct burners. To assess the correct performance of the developed model two kinds of data verification were performed. In the first kind of data verification, the program output was compared with the measured data collected from a cold start-up of an HRSG at Tehran CCPP. The variations of gas, water/steam and metal temperatures at various sections of HRSG, and pressure in drums were among the studied parameters. Mean differences of about 3.8% for temperature and about 9.2% for pressure were observed in this data comparison. In the second kind of data verification, the steady-state numerical output of the model was checked with the output of the well-known commercial software. An average difference of about 1.5% was found between the two latter groups of data. Copyright © 2007 John Wiley & Sons, Ltd. [source] Daily pattern of some fatty acids in the athletic horseJOURNAL OF ANIMAL PHYSIOLOGY AND NUTRITION, Issue 1 2009G. Piccione Summary In the sport field, non-esterified fatty acids (NEFA) are important for the physical performance during the aerobic exercise of short intensity and long duration. In man, rat, goat and in the sedentary horse studies on the chronometabolism showed the presence of a circadian rhythm of the plasmatic concentration of NEFA while data for the athletic horse are lacking. To define a chronogram helpful for a specific planning and the differentiation of the training programmme in the athletic horse, the circadian pattern of some fatty acids (NEFA, palmitic, stearic, oleic, linoleic and linolenic acids) was studied in five Sella Italiana horses. These horses trained following a daily model of activity consisting of walk, trot, gallop and jump of obstacles of different heights. Blood samples were collected from the jugular vein every 4 h, starting at 08:00 hours, for 2 days to assess the concentrations of total NEFA (by spectrophotometry), palmitic, stearic, oleic, linoleic and linolenic acids (by gas chromatography). anova for repeated measures showed a statistical significant effect of the time of the day in NEFA, oleic and linolenic acids. The application of the periodic model showed the periodic pattern of NEFA, oleic, linoleic and linolenic acids. Acrophases were in the afternoon for all parameters. The results obtained showed a different trend of the circadian pattern of the studied parameters in the athletic horse than in the sedentary one because the physical activity and the post-prandial metabolism acted as zeitgebers. [source] Effects of long-term administration of N-3 polyunsaturated fatty acids (PUFA) and selective estrogen receptor modulator (SERM) derivatives in ovariectomized (OVX) miceJOURNAL OF CELLULAR BIOCHEMISTRY, Issue 2 2003L. Zeitlin Abstract We studied the beneficial effects of dietary consumption of n-3 polyunsaturated fatty acids (PUFA) and two selective estrogen receptor modulator (SERM) derivatives (SERM-I and SERM-II) and their combined effect on serum lipids, skin dermis and adipose layers, bone marrow adipogenesis, and cytokine secretion in mice. Two different ovariectomized (OVX) models were studied: treatment began immediately post-OVX in one and 3 months post-OVX in the other. Our results showed that n-3 PUFA and both SERMs decreased triglyceride levels in the serum, and that SERMs also decreased serum cholesterol levels while n-3 PUFA had no similar effect. SERMs had no effect on IL-6, IL-1 beta, or IL-10 levels, but they decreased ex vivo tumor necrosis factor (TNF-,). N-3 PUFA decreased secretion of non-induced IL-6 and TNF-, from cultured BMC and IL-1 beta levels in vivo (i.e., in bone marrow plasma), but its main effect was a significant elevation in the secretion of IL-10, a known anti-inflammatory cytokine. OVX-induced B-lymphopoiesis was not affected by LY-139481 (SERM-I) while LY-353381 (SERM-II) exhibited an estrogen-antagonistic effect in sham and OVX mice and elevated the amount of B-cells in bone marrow. Fish oil consumption prevented the elevation in B-lymphopoiesis caused by OVX, but had no curative effect on established augmented B-lymphopoiesis. This activity could be mediated via the elevation of IL-10 which was shown to suppress B-lymphopoiesis. Both SERMs and n-3 PUFA inhibited the increase in adipose tissue thickness caused by OVX in mice. Our results showed that n-3 PUFA, could prevent some of the deleterious outcomes of estrogen deficiency that were not affected by SERMs. We observed no significant beneficial effects of the combined administration of SERM-I, SERM-II, and PUFA on the studied parameters. The exact mechanism by which polyunsaturated fatty acids exert their activities is still not clear, but peroxisome proliferator-activated receptors (PPARs) might be involved in processes which are modulated by n-3 PUFA. J. Cell. Biochem. 90: 347,360, 2003. © 2003 Wiley-Liss, Inc. [source] Splenectomy and thrombosis: the case of thalassemia intermediaJOURNAL OF THROMBOSIS AND HAEMOSTASIS, Issue 10 2010A. T. TAHER See also Mannucci PM. Red cells playing as activated platelets in thalassemia intermedia. This issue, pp 2149,51. Summary.,Background:,Hypercoagulability in splenectomized patients with thalassemia intermedia (TI) has been extensively evaluated. However, clinical and laboratory characteristics of patients who eventually develop overt thromboembolic events (TEE) are poorly studied. Patients/Methods:,Three Groups of TI patients (n = 73 each) were retrospectively identified from a registry involving six centers across the Middle East and Italy: Group I, all splenectomized patients with a documented TEE; Group II, age- and sex-matched splenectomized patients without TEE; and Group III, age- and sex-matched non-splenectomized patients without TEE. Retrieved data included demographics, laboratory parameters, clinical complications, and received treatments that may influence TEE development, and reflected the period prior to TEE occurrence in Group I. Results:,The mean age of Group I patients at development of TEE was 33.1 ± 11.7 years, with a male to female ratio of 33:40. TEE were predominantly venous (95%) while four patients (5%) had documented stroke. Among studied parameters, Group I patients were more likely to have a nucleated red blood cell (NRBC) count , 300 × 106 L,1, a platelet count , 500 × 109 L,1 and evidence of pulmonary hypertension (PHT), or be transfusion naïve. The median time to thrombosis following splenectomy was 8 years. Patients with an NRBC count , 300 × 106 L,1, a platelet count , 500 × 109 L,1, or who were transfusion naive also had a shorter time to thrombosis following splenectomy. Conclusion:,Splenectomized TI patients who will develop TEE may be identified early on by high NRBC and platelet counts, evidence of PHT, and transfusion naivety. [source] Developing a novel alkaline anion exchange membrane derived from poly(ether-imide) for improved ionic conductivityPOLYMERS FOR ADVANCED TECHNOLOGIES, Issue 8 2010Guigui Wang Abstract We have developed a novel alkaline anion exchange membrane derived from poly(ether-imide) for improved ionic conductivity. The effects of several important parameters on the chloromethylation of the membrane were investigated. These parameters included reaction temperature, reaction time, concentration of chloromethylation agent, concentration of polymer, and the amount of catalyst. The quaternization of the synthesized chloromethylated polymer was studied as well. The results show that all the studied parameters exhibited significant impacts on chloromethylation. Among them, the concentration of the chloromethylation agent played a key role in increasing the chloromethyl functional group attachment onto the polymer. It was found that the gelation could be avoided if these reaction parameters were controlled. It was also found that using an appropriate quaternization approach could significantly improve the ionic conductivity and optimize the conductivity of the membrane even though the functional chloromethyl groups attached to the polymer are limited. Copyright © 2009 John Wiley & Sons, Ltd. [source] Contributions of folding cores to the thermostabilities of two ribonucleases HPROTEIN SCIENCE, Issue 2 2002Srebrenka Robic Abstract To investigate the contribution of the folding cores to the thermodynamic stability of RNases H, we used rational design to create two chimeras composed of parts of a thermophilic and a mesophilic RNase H. Each chimera combines the folding core from one parent protein and the remaining parts of the other. Both chimeras form active, well-folded RNases H. Stability curves, based on CD-monitored chemical denaturations, show that the chimera with the thermophilic core is more stable, has a higher midpoint of thermal denaturation, and a lower change in heat capacity (,Cp) upon unfolding than the chimera with the mesophilic core. A possible explanation for the low ,Cp of both the parent thermophilic RNase H and the chimera with the thermophilic core is the residual structure in the denatured state. On the basis of the studied parameters, the chimera with the thermophilic core resembles a true thermophilic protein. Our results suggest that the folding core plays an essential role in conferring thermodynamic parameters to RNases H. [source] Effects of oral alpha-tocopherol on lung response in rat model of allergic asthmaRESPIROLOGY, Issue 4 2006Jana SUCHANKOVA Objective and background: Asthma is a chronic inflammatory disease in which an oxidant/antioxidant imbalance plays an important role. d -alpha-tocopherol (biologically the most active form of vitamin E) has redox properties and by scavenging the free radicals can act as an antioxidant. The aim of this study was to examine the effects of orally administered alpha-tocopherol in a rat model of allergic asthma. Methodology: Actively sensitized rats (OA) were treated with alpha-tocopherol (400 mg/kg/day for 10 days) or vehicle; 1 h after the last dose, they were challenged with antigen aerosol. The antigen-induced airway hyperresponsiveness to direct bronchoconstrictor (serotonin), the inflammatory cell infiltrate and histological changes were determined 1 or 24 h after the antigen challenge. Results: Alpha-tocopherol pretreatment was not significantly effective at reducing the studied parameters when compared with controls, even though there was a tendency to a reduction in bronchial responsiveness and in eosinophil and neutrophil infiltration. Conclusion: Alpha-tocopherol when administered in the chosen study design in an animal model of asthma had no major effect on airway inflammation. The effect of antioxidants deserves further evaluation. [source] Changes in the nutritional parameters of muscles of the common carp (Cyprinus carpio) and the silver carp (Hypophthalmichthys molitrix) following environmental exposure to cyanobacterial water bloomAQUACULTURE RESEARCH, Issue 2 2009Jan Mares Abstract The present study evaluated the effect of naturally developing cyanobacteria on the composition of muscles of two commercially important freshwater fish species. Fish were exposed to cyanobacterial biomass including Microcystis aeruginosa and Microcystis ichthyoblabe for 4 weeks. Then, they were transferred to dechlorinated potable water without any cyanobacteria for another 4-week period, thus modelling their preparation for consumers. Samples of muscles were collected every week during exposure and subsequent stay in dechlorinated potable water. The cyanobacterial water bloom of 3.9,6 × 105 cells mL,1 (133,383 ,g g,1 of total MC DW) induced statistically significant effects only in the content of fatty acids (P<0.05; P<0.01) in the common carp (Cyprinus carpio), while all studied parameters including the content of dry matter and fat (P<0.01), proteins (P<0.05), fatty acid composition (P<0.05; P<0.01) and some amino acids (P<0.05) were affected in the silver carp (Hypophthalmichthys molitrix). This study has shown that cyanobacteria in the environment of commercially produced fish may decrease the dietetic value of fish muscles. [source] Fine Root Distribution in a Lower Montane Rain Forest of PanamaBIOTROPICA, Issue 3 2009Dirk Hölscher ABSTRACT In a Panamanian lower montane rain forest we: (1) analyzed the vertical and horizontal distribution of fine roots; and (2) assessed the relationship of fine root mass to thickness of the soil organic layer, soil pH, and soil-extractable nitrogen. The soil in the study area has developed on volcanic ash deposits and was classified as Hapludand. In randomly distributed samples, the median fine root mass (biomass and necromass, diam , 2 mm) to a depth of 100 cm mineral soil was 544 g/m2, 41 percent of which was found in the organic layer. Fine root mass was approximately twice as high in the vicinity of stems of the tree species Oreomunnea mexicana (1069 g/m2) and the palm species Colpothrinax aphanopetala (1169 g/m2) and was associated with thick organic layers. The median thickness of the soil organic layer in a larger random sample (N= 64) was 8 cm with a considerable variation (interquartile range: 7 cm). In these samples, the density of fine root biomass was correlated with the concentration of extractable nitrogen (r= 0.33, P= 0.011), and on an areal basis, fine root biomass in the organic layer increased with increasing thickness of the organic layer (r= 0.63, P < 0.001) and decreasing pHKCl (r=,0.33, P < 0.01). Fine root biomass in the upper mineral soil did not show significant correlations with any of the studied parameters. RESUMEN En un bosque panameño bajo montano tropical (1) analizamos la distribución horizontal y vertical de las raíces finas, y (2) evaluamos la relación de la masa de las raíces finas con el espesor de la capa de suelo orgánico, pH del suelo, y nitrógeno extraíble del suelo. El suelo del área de estudio se ha desarrollado en depósitos de ceniza volcánica y fue clasificado como Hapludand. En muestras distribuidas aleatoriamente, la media de la masa de raíces finas (biomasa y masa necrosada, diámetro , 2 mm) a una profundidad de 100 cm del suelo mineral fue 544 g/m2, 41 por ciento de las cuales fueron encontradas en suelo orgánico. La masa de raíces finas fue aproximadamente el doble en la vecindad entre los pies de especies de árboles Oreomunnea mexicana (1069 g/m2) y especies de palmera Colpothrinax aphanopetala (1169 g/m2) y fue asociada con el espesor de capa orgánica. El espesor mediano de la capa de suelo orgánico en una amplia muestra aleatoria (N= 64) fue 8 cm con una considerable variación (intervalo entre cuartilas: 7 cm). En estas muestras, la densidad de raíces finas fue correlacionada con la concentración de nitrógeno extraíble (r= 0.33, P= 0.011), y en base al área, la biomasa de raíces finas en la capa orgánica aumentó con el incremento del espesor de la capa orgánica (r= 0.63, P < 0.001) y decrecimiento del pHKCl (r=,0.33, P < 0.01). La biomasa de raíces finas en el suelo mineral superior no mostró ninguna significante correlación con los parámetros estudiados. [source] New classification of oesophageal and gastric carcinomasBRITISH JOURNAL OF SURGERY (NOW INCLUDES EUROPEAN JOURNAL OF SURGERY), Issue 3 2001K. Dolan Background: The current International Classification of Diseases (ICD)-O classification of carcinomas of the oesophagus and stomach causes epidemiological and clinical confusion, particularly the use of the term cardia and the overlapping subsites described in the stomach. This study compared the epidemiological and clinical features of each subtype and subsite of carcinoma of the oesophagus and stomach to assess requirements for a new classification of these carcinomas. Methods: Data were extracted with appropriate validity checks on all cases of oesophageal and gastric carcinoma identified throughout the period 1974,1993 by the Merseyside and Cheshire Cancer Registry, which covers a population of 2·5 million. Comparison of all identifiable epidemiological and clinical features of adenocarcinomas at four different subsites, namely the upper two-thirds of the oesophagus, the lower third of the oesophagus, cardia and subcardia of the stomach, was performed. Results: There were 5322 primary carcinomas of the oesophagus and 10 535 carcinomas of the stomach registered between 1974 and 1993. The incidence of adenocarcinoma of the lower oesophagus and cardia trebled in males and doubled in females, whereas adenocarcinoma of the subcardia region of the stomach declined in both sexes. The incidence of adenocarcinoma of the lower oesophagus and of the cardia was similar for median age at diagnosis, male: female ratio, percentage of patients who smoked, and survival; both were significantly different from values for carcinoma of the subcardia in these respects. Conclusion: These data suggest that there is considerable overlap between adenocarcinomas of the lower oesophagus and adenocarcinomas currently classified as of the cardia. The authors believe this is due to the group of carcinomas classified as cardia consisting mainly of carcinomas that traverse the gastro-oesophageal junction. These carcinomas were different in all studied parameters from carcinomas of the stomach and should be classified separately from gastric carcinomas. A new subsite classification of oesophageal and gastric carcinomas is proposed that includes the gastro-oesophageal junction as a subsite of the oesophagus and that simplifies the subsite classification of the stomach into proximal, distal and overlapping. © 2001 British Journal of Surgery Society Ltd [source] | |||||||||||||||||||