Comparative Assessment (comparative + assessment)

Distribution by Scientific Domains


Selected Abstracts


Comparative Assessment of Coagulation Changes Induced by Two Different Types of Heart,Lung Machine

ARTIFICIAL ORGANS, Issue 1 2010
Niels Rahe-Meyer
Abstract The cardiopulmonary bypass (CPB) used in heart surgery has a deleterious effect on hemostasis. The aim of our study was to assess by means of standard laboratory and point-of-care methods changes induced by CPB in coagulation parameters, particularly in platelet function, and to determine whether these changes differ depending on the type of heart,lung machine (HLM) used: minimal extracorporeal circulation system (MECC) and standard HLM. The study enrolled 88 patients scheduled for coronary artery bypass surgery performed on pump. Forty-four interventions were performed with MECC and 44 with standard HLM. Blood was sampled preoperatively, after 30 min on CPB, after weaning from CPB, and 24 h postoperatively. Coagulation and platelet function were assessed using multiple electrode aggregometry (MEA), rotation thromboelastometry, as well as standard laboratory tests. Rotation thromboelastometry and standard laboratory reflected significantly impaired hemostasis after weaning from CPB but no significant differences between the two groups at different time points. Aggregation decreased significantly in both groups as early as 30 min after the institution of CPB (P < 0.05, Mann,Whitney U -test) and recovered within the first 24 h postoperatively, without reaching the preoperative level. Intraoperatively, aggregometry values reflected a significantly more severe reduction of platelet function in standard HLM group than in the MECC group (P < 0.01, ProcMixed test). Our findings suggest that MEA and thromboelastometry reflect impairment of coagulation in cardiac surgery performed on different types of HLM and that platelet function is less affected by MECC than by standard HLM. [source]


Comparative assessment of time-related bioactive glass and calcium hydroxide effects on mechanical properties of human root dentin

DENTAL TRAUMATOLOGY, Issue 1 2009
Monika Marending
These materials have a disinfecting capacity similar to Ca(OH)2, but bear the advantage of bioactivity. However, because bioactive glasses initially act as alkaline biocides just as Ca(OH)2 does, they may also negatively affect mechanical dentin properties over time. This was assessed in the current study using standardized human root dentin bars. Specimens were immersed in 1:20 (wt vol,1) suspensions of nanometric bioactive glass 45S5 or calcium hydroxide for 1, 10, or 30 days. Control specimens were immersed in pure saline for 30 days (n = 20 per group). Subsequently, modulus of elasticity (E) and flexural strength (FS) of the specimens were determined. Results were compared between groups using one-way anova and Scheffé's post-hoc test. Ca(OH)2 caused a significant (P < 0.001) 35% drop in mean flexural strength values compared to the control treatment after 10 days. No further change was observed between 10 days and 30 days. Bioactive glass caused a 20% drop in mean flexural strength as compared to the control after 10 days. However, this difference did not reach statistical significance (P > 0.05). No effects of either material on dentin modulus of elasticity values were observed. It was concluded that the calcium hydroxide suspension affected the dentin more than the bioactive glass counterpart; however, the effect was self-limiting and probably restricted to superficial dentin layers, as suggested by the mere decrease in flexural strength but not in modulus of elasticity values. [source]


Comparative assessment of two distributed watershed models with application to a small watershed

HYDROLOGICAL PROCESSES, Issue 11 2006
Latif Kalin
Abstract Distributed watershed models are beneficial tools for the assessment of management practices on runoff and water-induced erosion. This paper evaluates, by application to an experimental watershed, two promising distributed watershed-scale sediment models in detail: the Kinematic Runoff and Erosion (KINEROS-2) model and the Gridded Surface Subsurface Hydrologic Analysis (GSSHA) model. The physics behind each model are to some extent similar, though they have different watershed conceptualizations. KINEROS-2 was calibrated using three rainfall events and validated over four separate rainfall events. Parameters estimated by this calibration process were adapted to GSSHA. With these parameters, GSSHA generated larger and retarded flow hydrographs. A 30% reduction in both plane and channel roughness in GSSHA along with the assumption of Green-Ampt conductivity KG-A = Ks, where Ks is the saturated conductivity, resulted in almost identical hydrographs. Sediment parameters not common in both models were calibrated independently of KINEROS-2. A comparative discussion of simulation results is presented. Even though GSSHA's flow component slightly overperformed KINEROS-2, the latter outperformed GSSHA in simulations for sediment transport. In spite of the fact that KINEROS-2 is not geared toward continuous-time simulations, simulations performed with both models over a 1 month period generated comparable results. Copyright © 2006 John Wiley & Sons, Ltd. [source]


Comparative assessment of soybean meal with high and low glucosinolate rapeseed,mustard cake as protein supplement on performance of growing crossbred calves

JOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE, Issue 5 2008
S Ravichandiran
Abstract BACKGROUND: Feeding of high glucosinolate rapeseed,mustard cakes (RMCs) imparts adverse effects on dry matter (DM) intake, health and overall performance of animals. Recently, plant breeding efforts have resulted in many cultivars of RMCs containing low to moderate levels of glucosinolate in India. The feeding value of RMC cultivars with high and low glucosinolate was evaluated relative to commonly used soybean meal as a protein supplement in growing crossbred calves. RESULTS: Eighteen growing crossbred calves (62.9 ± 3.8 kg body weight) were randomly allocated to three dietary treatments SBM, LG and HG containing soybean meal, low glucosinolate B. napus (15 µmol glucosinolates g,1) and high glucosinolate B. juncea (135 µmol glucosinolates g,1), respectively. Although daily intake of total DM and wheat straw did not differ (P > 0.05) among the dietary treatments, intake (g/kgW0.75) of concentrate moiety decreased quadratically (P < 0.01) with increasing glucosinolate levels in diets. Nutrient digestibility and balances of N, Ca and P by calves were similar (P > 0.05) among dietary treatments. However, average daily gain (g) decreased and feed conversion ratio values increased quadratically (P < 0.05) with increasing glucosinolate levels. Serum metabolic profile and triiodothyronine remained within the normal range; however, thyroxine changed quadratically. CONCLUSION: The results suggested that while high glucosinolate RMCs may reduce the palatability and consequently growth rate in crossbred calves, SBM can be replaced completely by low glucosinolate rapeseed without compromising their performance. Copyright © 2008 Society of Chemical Industry [source]


Comparative assessment of the water balance and hydrology of selected Ethiopian and Kenyan Rift Lakes

LAKES & RESERVOIRS: RESEARCH AND MANAGEMENT, Issue 3 2008
Tenalem Ayenew
Abstract The study area is part of the East African Rift system, characterized by a cluster of lakes occupying an extremely faulted rift floor with geothermal manifestations. Some of the lakes illustrated contrasting water levels and size evolution over the last few decennia, believed to have been caused by various natural and anthropogenic factors. The relative importance of these factors, however, is unknown. This study attempts to present the hydrology of the lakes in a broader context, by giving more emphasis to lake water level fluctuations and to the water balance. These factors have far-reaching implications in regard to future management of the lake basin water. It also provides information on the relation of the groundwater with the lakes, and with the local and regional groundwater flow system from the adjacent highlands to the floor of the Rift. The methods utilized in this study include conventional hydrogeological field surveys, and hydrometeorological and data analyses, coupled with digital image processing and spatial analysis under a Geographic Information System environment. Ancillary supporting information has been obtained from environmental isotopes and hydrochemical data. The study results indicate the terminal Ethiopian lakes changed in size and water level significantly over the last half century. In contrast, the Kenyan lakes only exhibited slight changes. The lakes in both countries exhibit a striking similarity in their subsurface hydraulic connection, and are strongly governed by complex rift geological structures. Groundwater plays a vital role in the water balance of the study lakes. The study results indicate that future sustainable use of the study lakes demands that serious attention be given to the role of the groundwater component of the lake water balances. [source]


Comparative assessment of enzyme-linked immunosorbent assay and Western blot for the diagnosis of toxocariasis in patients with skin disorders

BRITISH JOURNAL OF DERMATOLOGY, Issue 1 2010
A-P. Bellanger
Summary Background, The link between various chronic skin disorders and toxocariasis was previously demonstrated by case reports and several case,control studies. However, these previous studies were based only on the Toxocara canis excretory-secretory,enzyme-linked immunosorbent assay (TES,ELISA) serological technique, which is not specific due to cross-reactivity with parasites of the genera Anisakis or Ascaris. Immunoblot analysis is highly specific and can detect very low levels of Toxocara antibodies. Therefore, this technique may be useful in the identification of Toxocara infection in patients with chronic skin disorders. Objectives, Because urticaria and pruritus/prurigo are skin conditions previously associated with toxocariasis, we carried out a prospective study using both TES,ELISA and Toxocara Western blot on 113 patients with either chronic urticaria (n = 84) or chronic pruritus (n = 29). Methods, Patients were matched with controls according to gender, age and residence location (rural or urban area). Data were analysed using a Mantel,Haenszel ,2 test. Results, The proportion of positive TES,ELISA results was not significantly different for patients with chronic skin disorders (urticaria or pruritus/prurigo) from that of control subjects. However, the proportion of positive immunoblot results was significantly higher for patients with chronic urticaria than for control subjects (P = 0·009). Conclusions, Our study demonstrates the need to perform Western blotting immunodiagnosis, whatever the TES,ELISA result, to improve diagnosis of human toxocariasis in patients with chronic urticaria caused by Toxocara infection. [source]


Comparative assessment of S. aureus microbial biofilm inhibition by an N-alkyl-polyethyleneimine covalently attached to PMMA or titanium in the Boston Keratoprosthesis

ACTA OPHTHALMOLOGICA, Issue 2009
I BEHLAU
Purpose Biofilms are matrix-associated microbial communities adherent to either biological surfaces or abiotic surfaces. They account for the majority of device-associated infections. Our goal herein is to minimize bacterial adherence and biofilm formation by comparative analysis of new polycations bound to bio-prosthetic ocular-associated materials, poly (methyl methacrylate) (PMMA) or titanium, using the Boston KPro as a model system. Methods Using S.aureus ocular-associated clinical isolates, a quantitative assessment of microbial biofilm formation by linear N,N-dodecyl,methyl-polyethyleneimine (DMPEI) (217 kDa) covalently bound to PMMA or titanium compared to the parent PMMA or Ti, respectively, has been performed using confocal laser scanning and electron microscopies. In addition, DMPEI-bound materials have been screened for corneal toxicity in both cell tissue culture and rodent models, and as compared to the original materials. Results A marked inhibitory effect in S. aureus biofilm formation on DMPEI-derivatized materials compared to the parent PMMA (3-4 fold) and Ti (2-fold), without conferring additional epithelial cell cytotoxicity in vitro, has been observed. Furthermore, we have found no additional tissue reactivity, and possibly even a protective effect, with DMPEI-derivatized materials in vivo. Conclusion We found that covalent derivatization with DMPEI of PMMA and Ti greatly reduces S. aureus biofilm formation in vitro compared to the parent materials. There was no additional cytotoxicity seen both in vitro and in vivo. Future studies will evaluate DMPEI-derivatized materials for in vivo antimicrobial efficacy. [source]


Quantitation of cytological parameters of malignant lymphocytes using computerized image analysis

INTERNATIONAL JOURNAL OF LABORATORY HEMATOLOGY, Issue 4 2008
S. A. HAMID JAHANMEHR
Summary Computerized image analysis may add to morphological evaluation by turning qualitative data into quantitative values. In this study, image analysis program was used to quantitate cytological parameters of lymphocytes in B-cell lymphoproliferative disorders. Chronic lymphocytic leukemia (CLL), mantle cell lymphoma (MCL) and B-cell prolymphocytic leukemia (B-PLL) were selected to represent typically small, medium, and large-sized lymphocytes, respectively. Image analysis was performed to determine the morphological parameters. A set of measurements was generated for quantitation of total cell area, cell diameter, cytoplasm area, nuclear area, nuclear/cell ratio, and nuclear density. The quantitated parameters substantiated morphological characteristics of the tumor cells. Comparative assessments demonstrated that CLL, MCL, and PLL can be differentiated by the quantitative descriptors. The results from image analysis may assist in defining morphological criteria and in developing quantitative cell morphology. [source]


Reference data for evaluating the growth of common riverine fishes in the UK

JOURNAL OF APPLIED ICHTHYOLOGY, Issue 5 2007
J. R. Britton
Summary Comparative assessments of population mean growth rates in length remain important aspects of stock assessment in river fisheries. To facilitate these assessments, for 15 fish species encountered in UK rivers reference data are provided on their expected lengths at age, maximum theoretical lengths (L,), growth coefficient (K) and instantaneous mortality rate (Z). These data are also transferable to fish populations outside of the UK that experience a similar growth season (approximately April to October, mean water temperatures 12,22°C). Considerable plasticity was observed in the growth of all species examined, with length at age values revealing growth rates from very slow to very fast. Populations considered fast growing against reference data were coincident with a relatively low ultimate length, a high growth coefficient and a high instantaneous mortality rate, suggesting a trade-off exists between growth rate, ultimate length and life span. [source]


Graphical user interfaces in an engineering educational environment

COMPUTER APPLICATIONS IN ENGINEERING EDUCATION, Issue 1 2005
Christopher Depcik
Abstract Graphical user interfaces (GUIs) are being increasingly used in the classroom to provide users of computer simulations with a friendly and visual approach to specifying all input parameters and increased configuration flexibility. In this study, the authors first describe a number of software and language options that are available to build GUIs. Subsequently, a comprehensive comparative assessment of possible alternatives is undertaken in the light of a benchmark educational program used in a course on computational fluid dynamics (CFD) at the University of Michigan. For the GUIs presented, their educational value with respect to flexible data entry and post-processing of results has been demonstrated. In addition, the authors offer recommendations for pros and cons of available options in terms of platform independence, ease of programming, facilitation of interaction with students, and flexibility. © 2005 Wiley Periodicals, Inc. Comput Appl Eng Educ 13: 48,59, 2005; Published online in Wiley InterScience (www.interscience.wiley.com); DOI 10.1002/cae.20029 [source]


Chronic toxicity of five structurally diverse demethylase-inhibiting fungicides to the crustacean Daphnia magna: A comparative assessment

ENVIRONMENTAL TOXICOLOGY & CHEMISTRY, Issue 6 2009
Enken Hassold
Abstract Demethylase inhibitors (DMIs) are broad-spectrum fungicides that are ubiquitously used in agriculture and medicine. They comprise chemically heterogeneous substances that share a common biochemical target in fungi, the inhibition of a specific step in sterol biosynthesis. Several DMIs are suspected to disrupt endocrine-mediated processes in a range of organisms and to inhibit ecdysteroid biosynthesis in arthropods. It is unclear, however, whether and, if so, to what extent different DMI fungicides have a similar mode of action in nontarget organisms, which in turn would lead to a common chronic toxicity profile. Therefore, we selected a representative of each of the major DMI classes,-the piperazine triforine, the pyrimidine fenarimol, the pyridine pyrifenox, the imidazole prochloraz, and the triazole triadimefon,-and comparatively investigated their chronic toxicity to Daphnia magna. No toxicity was detectable up to the limit of solubility of triforine (61 ,mol/L). All other DMIs reduced reproductive success by delaying molting and development and by causing severe developmental abnormalities among offspring. Prochloraz was most toxic (median effective concentration [EC50] for fecundity reduction, 0.76 ,mol/L), followed by fenarimol (EC50, 1.14 ,mol/L), pyrifenox (EC50, 3.15 ,mol/L), and triadimefon (EC50, 5.13 ,mol/L). Mean effect concentrations for fecundity reduction were related to lipophilicity and followed baseline toxicity. However, triadimefon and fenarimol (but none of the other tested DMIs) caused severe eye malformations among exposed offspring. Affected neonates did survive, but a reduced ecological fitness can be assumed. Offspring exposed to fenarimol in mater matured earlier. The investigated different life-history parameters were affected in a substance-specific manner. These qualitatively different toxicity profiles suggest additional, substance-specific mechanisms of action in D. magna that probably are related to an antiecdysteroid action. [source]


Assessing the effects of measurement errors on the estimation of production functions

JOURNAL OF APPLIED ECONOMETRICS, Issue 6 2006
Carmine Ornaghi
This article explores to what extent the poor results that are often found when estimating parameters of production functions can be attributed to measurement errors, due to the use of common price deflators across firms. Because of the lack of detailed micro-economic data, econometricians have to rely on industry-wide deflators when computing outputs and intermediate inputs. A unique feature of the longitudinal data used in this paper is that it reports firm-level prices. This allows for a comparative assessment of production function parameters where the outputs and intermediate inputs are computed using both firm-specific prices and industry-wide deflators. The empirical results presented in this paper show that the use of common deflators across firms leads to lower scale estimates, mainly because of a large downward bias in the estimated coefficients for labour. Copyright © 2006 John Wiley & Sons, Ltd. [source]


Bioactive and mechanically strong Bioglass®-poly(D,L -lactic acid) composite coatings on surgical sutures

JOURNAL OF BIOMEDICAL MATERIALS RESEARCH, Issue 2 2006
Q. Z. Chen
Abstract New coating processes have been investigated for degradable (Vicryl®) and nondegradable (Mersilk®) sutures with the aim to develop Bioglass® coated polymer fibers for wound healing and tissue engineering scaffold applications. First, the aqueous phase of a Bioglass® particle slurry was replaced with a poly(D,L -lactic acid) (PDLLA) polymer dissolved in solvent dimethyle carbonate (DMC) to act as third phase. SEM observations indicated that this alteration significantly improved the homogeneity of the coatings. Second, a new coating strategy involving two steps was developed: the sutures were first coated with a Bioglass®,PDLLA composite film followed by a second PDLLA coating. This two-step process of coating has addressed the problem of poor adherence of Bioglass® particles on suture surfaces. The coated sutures were knotted to determine qualitatively the mechanical integrity of the coatings. The results indicated that adhesion strength of coatings obtained by the two-step method was remarkably enhanced. A comparative assessment of the bioactivity of one-step and two-step produced coatings was carried out in vitro using acellular simulated body fluid (SBF) for up to 28 days. Coatings produced by the two-step process were found to have similar bioactivity as the one-step produced coatings. The novel Bioglass®/PDLLA/Vicryl® and Bioglass®/PDLLA/Mersilk® composite sutures are promising bioactive materials for wound healing and tissue engineering applications. © 2005 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2006 [source]


Review: Microscale methods for high-throughput chromatography development in the pharmaceutical industry

JOURNAL OF CHEMICAL TECHNOLOGY & BIOTECHNOLOGY, Issue 7 2009
Sunil Chhatre
Abstract Demands within the pharmaceutical sector to cut costs and improve process efficiencies have grown considerably in recent years. Major challenges exist for companies trying to establish financially viable and robust manufacturing processes for increasingly complex therapeutics. These issues have driven the investigation of miniaturised process-design techniques by which to identify suitable operating conditions using small volumes of feed material typical of that available in the early stages of bioprocess development. Such techniques are especially valuable for the optimisation of chromatographic separations, which often represent a significant percentage of manufacturing costs and hence for which there is a pressing need to determine the best operating policies. Several methods employing microlitre volumes of sample and resin have been explored recently, which are aimed at the high-throughput and cost-effective exploration of the design space for chromatographic separations. This methodology paper reviews these microscale approaches and describes how they work, gives examples of their application, discusses their advantages and disadvantages and provides a comparative assessment of the different methods, along with a summary of the challenges that remain to be overcome in relation to these techniques. Copyright © 2009 Society of Chemical Industry [source]


An Empirical Assessment of Country Risk Ratings and Associated Models

JOURNAL OF ECONOMIC SURVEYS, Issue 4 2004
Suhejla Hoti
Abstract., Country risk has become a topic of major concern for the international financial community over the last two decades. The importance of country ratings is underscored by the existence of several major country risk rating agencies, namely the Economist Intelligence Unit, Euromoney, Institutional Investor, International Country Risk Guide, Moody's, Political Risk Services, and Standard and Poor's. These risk rating agencies employ different methods to determine country risk ratings, combining a range of qualitative and quantitative information regarding alternative measures of economic, financial and political risk into associated composite risk ratings. However, the accuracy of any risk rating agency with regard to any or all of these measures is open to question. For this reason, it is necessary to review the literature relating to empirical country risk models according to established statistical and econometric criteria used in estimation, evaluation and forecasting. Such an evaluation permits a critical assessment of the relevance and practicality of the country risk literature. The paper also provides an international comparison of risk ratings for twelve countries from six geographic regions. These ratings are compiled by the International Country Risk Guide, which is the only rating agency to provide detailed and consistent monthly data over an extended period for a large number of countries. The time series data permit a comparative assessment of the international country risk ratings, and highlight the importance of economic, financial and political risk ratings as components of a composite risk rating. [source]


Libcitations: A measure for comparative assessment of book publications in the humanities and social sciences

JOURNAL OF THE AMERICAN SOCIETY FOR INFORMATION SCIENCE AND TECHNOLOGY, Issue 6 2009
Howard D. White
Bibliometric measures for evaluating research units in the book-oriented humanities and social sciences are underdeveloped relative to those available for journal-oriented science and technology. We therefore present a new measure designed for book-oriented fields: the "libcitation count." This is a count of the libraries holding a given book, as reported in a national or international union catalog. As librarians decide what to acquire for the audiences they serve, they jointly constitute an instrument for gauging the cultural impact of books. Their decisions are informed by knowledge not only of audiences but also of the book world (e.g., the reputations of authors and the prestige of publishers). From libcitation counts, measures can be derived for comparing research units. Here, we imagine a match-up between the departments of history, philosophy, and political science at the University of New South Wales and the University of Sydney in Australia. We chose the 12 books from each department that had the highest libcitation counts in the Libraries Australia union catalog during 2000 to 2006. We present each book's raw libcitation count, its rank within its Library of Congress (LC) class, and its LC-class normalized libcitation score. The latter is patterned on the item-oriented field normalized citation score used in evaluative bibliometrics. Summary statistics based on these measures allow the departments to be compared for cultural impact. Our work has implications for programs such as Excellence in Research for Australia and the Research Assessment Exercise in the United Kingdom. It also has implications for data mining in OCLC's WorldCat. [source]


Dioxin-like and non-dioxin like effects of polychlorinated biphenyls: Implications for risk assessment

LAKES & RESERVOIRS: RESEARCH AND MANAGEMENT, Issue 3 2002
John P. Giesy
Abstract Polychlorinated biphenyls (PCBs) are persistent, bioaccumulative and toxic contaminants in the environment. Individual PCB congeners exhibit different physicochemical properties and biological activities that result in different environmental distributions and toxicity profiles. The variable composition of PCB residues in environmental matrices and their different mechanisms of toxicity complicate the development of scientifically based regulations for risk assessment. Various approaches for the assessment of risks of PCBs have been critically examined. Recent developments in the toxic equivalency factor (TEF) approach for the assessment of toxic effects due to dioxin-like PCBs have been examined. The PCB exposure studies that describe non-dioxin-like toxic effects, particularly neurobehavioural effects and their effective doses in animals, were compiled. A comparative assessment of effective doses for dioxin-like and non-dioxin-like effects by PCBs has been made to evaluate the relative significance of non- ortho and ortho -substituted PCBs in risk assessment. Using mink as an example, relative merits and implications of using TEF and total PCB approaches for assessing the potential for toxic effects in wildlife were examined. There are several advantages and limitations associated with each method used for PCB risk assessment. Toxic effects due to coplanar PCBs occur at relatively smaller concentrations than those due to non-dioxin-like PCBs and, therefore, the TEF approach derives the risk assessment of PCBs in the environment. The need for the refinement of the TEF approach for more accurate assessment of risks is discussed. [source]


Effect of rubber matrix type on the morphology and reinforcement effects in carbon black-nanoclay hybrid composites,A comparative assessment

POLYMER COMPOSITES, Issue 1 2010
S. Praveen
Carbon black (B),nanoclay (NC) hybrid composites, based on millable polyurethane and brominated isoprene isobutylene rubber (BIIR), were prepared. The carbon black loading was fixed at 20 phr and organically modified sodium montmorillonite clay loading varied from 5 to 20 phr in each rubber compounds. The nanocomposites were prepared in laboratory by mixing two-roll mill. The state of dispersion of the layered silicate was studied by X-ray diffraction (XRD) and transmission electron microscopy (TEM). XRD and TEM results indicated intercalation of PU and BIIR into the silicate interlayers, followed by exfoliation of the silicate layers into the elastomer matrices. However, the level of intercalation and exfoliation varied considerably with the type of elastomer. The reinforcing effects obtained were found to depend strongly on the extent and degree of the dispersion of the carbon black and silicate layers into the rubber matrices. Mechanical and dynamic mechanical properties were evaluated for each composite. POLYM. COMPOS., 2010. © 2009 Society of Plastics Engineers [source]


Metallocene based polyolefin: a potential candidate for the replacement of flexible poly (vinyl chloride) in the medical field

POLYMERS FOR ADVANCED TECHNOLOGIES, Issue 9 2010
M. C. Sunny
Abstract A comparative assessment of the performance properties of metallocene polyolefin (m-PO) with those of plasticized poly (vinyl chloride) (pPVC) and ethylene vinyl acetate (EVA) copolymer having 18% vinyl acetate content (EVA-18), the two common polymers used for flexible medical products, is carried out. The preliminary evaluation of the processability, mechanical properties, and thermal stability of the new material, m-PO is described. The processability parameters like mixing torque and melt viscosity of m-PO are found to be comparable with those of pPVC and EVA-18. Mechanical properties such as tensile strength, elongation at break, and tear strength (TS) of m-PO are much higher than that of pPVC and EVA-18. Thermo gravimetric analysis (TGA) indicates that the thermal degradation of m-PO takes place only at temperatures above 340°C and can be processed at 170°C without much damage. Oxygen and carbon dioxide permeabilities of m-PO at three different temperatures (10, 25, and 40°C) are evaluated and compared with those of pPVC and EVA-18. It could be seen that the permeabilities of both the gases for m-PO at three temperatures were lower than those of pPVC and EVA. Biological evaluation of m-PO is carried out by assessing its cytotoxicity, hemolytic property, and blood clotting initiation. The cytotoxicity studies indicate that m-PO is non-toxic to the monolayer of L929 mammalian fibroblast cell lines on direct contact or the exposure of its extract. Non-hemolytic property of m-PO by direct contact as well as test on extract is revealed both in static and in dynamic conditions. Blood clotting time experiments indicate that the initiation of blood clotting due to m-PO is faster than that of pPVC and EVA-18. Copyright © 2009 John Wiley & Sons, Ltd. [source]


A comparative assessment of psychological and psychosocial characteristics of cancer patients and their caregivers

PSYCHO-ONCOLOGY, Issue 1 2003
S. Rossi Ferrario
We recruited 50 cancer patients and their caregivers with the aim of extending our knowledge of emotional, personality and psychosocial variables, and comparing their reciprocal experience of the disease. The patients and caregivers were administered four of the questionnaires included in the Cognitive Behavioral Assessment 2.0, the Family Strain Questionnaire and the Satisfaction with Life Scale. The patients were characterised by significantly greater emotional disturbances than their caregivers, who were emotionally stable and had a relatively low level of perceived strain despite their high level of hostility and state anxiety. The intra-scale correlations highlighted the fact that the perception of distress depends on neuroticism and the presence of anxiety and depression (which are themselves known to be connected with neuroticism). The everyday life of the caregivers seemed to be characterised by restricted social relationships and interests; a relatively large proportion also declared that they had practical problems related to disease management, economics and some embarrassing and stigmatic aspects of the disease itself. Copyright © 2003 John Wiley & Sons, Ltd. [source]


An analysis on the subjective perception of policy action on peripherality: A comparative assessment in accessible and peripheral areas of six countries of the EU,

REGIONAL SCIENCE POLICY AND PRACTICE, Issue 2 2009
Joan Noguera
peripherality; regional development; policy analysis Abstract The paper presents an analysis of the subjective perception of the policy efficiency on peripherality in 12 regions of six countries of the EU. In each country two regions are selected: one peripheral but relatively dynamic and another accessible but relatively lagging. Public action conditions a range of processes and activities that continuously influence the intensity and direction of development. It can be part of the new factors of territorial development (NFTD) building up or hindering peripherality. The paper has the following aims: to identify what generic types of measures are believed to be more efficient for development; to analyse which measures (spatial or aspatial) are considered more important for development; to rank different NFTD according to preferences of interviewed experts; to identify whether there are differences between accessible and peripheral areas in policy preferences and needs; and to define which influences national contexts. A minimum of 5 experts per study area have been interviewed for this analysis. [source]


Immunohistochemistry of carbonic anhydrase isozymes (CA-I, II and III) in canine salivary glands: a distributional and comparative assessment

ANATOMIA, HISTOLOGIA, EMBRYOLOGIA, Issue 1 2000
M. Asari
The immunohistolocalization of carbonic anhydrase isozymes (CA-I, II, III) in canine salivary glands was studied using antiserum against CA-I, II, III. In parotid glands, immunostaining intensely localized cytosolic CA-II antiserum throughout the cytoplasm of acinar secretory cells and ductal epithelial cells, especially in the striated duct region. CA-III reactivity in the glands was only seen selectively at the intercalated ductal cells. In contrast, no immunoreaction localized CA-I in the gland. In the submandibular and sublingual glands, CA-I, II, and III were all observed in the ductal segments of the glands, whereas serous demilune appeared devoid of all three cytosolic CA isozymes. In contrast, in zygomatic glands (i.e. dorsal buccal glands) all CA isozymes were observed in both serous demilune and ductal segments. In all of the salivary glands examined, no mucous acinar cells were found to be reactive for any CA. [source]


A comparative assessment of molecular marker assays (AFLP, RAPD and SSR) for white yam (Dioscorea rotundata) germplasm characterization

ANNALS OF APPLIED BIOLOGY, Issue 3 2003
H D MIGNOUNA
Summary Several DNA-based marker systems are available for genetic fingerprinting of plants but information on their relative usefulness for yam germplasm characterisation is lacking. The efficiency of RAPD, AFLP and SSR markers for the assessment of genetic relationships, and for cultivar identification and discrimination among 45 West and Central African white yam cultivars belonging to 22 morphotypes/cultivar groups was investigated. Dendrograms were produced based on band pattern scores using the UPGMA method. Results showed that each of the three techniques could unequivocably identify each cultivar, but that techniques differed in the mean number of profiles generated per primer (or primer pair) per cultivar, referred to as genotype index (GI). The order of merit based on this criterion in this study was AFLPs (GI = 2.56), SSRs (GI = 0.39) and RAPDs (GI = 0.35). Yam genotypes classified in the same cultivar group based on morphology were often genetically different, emphasising the need for molecular fingerprinting in yam germplasm characterisation. AFLPs showed the highest efficiency in detecting polymorphism and revealed genetic relationships that most closely reflected morphological classification. [source]


Semantic learning designs: recording assumptions and guidelines

BRITISH JOURNAL OF EDUCATIONAL TECHNOLOGY, Issue 3 2006
Miguel-Angel Sicilia
Recent developments in the standardisation of learning technology have resulted in models of learning activities and resources including descriptive metadata and definitions of conditional flows for multirole activities. Nonetheless, such learning designs are actually representations of the results of the design process and do not provide information about the rationale of the design, ie, about the theoretical standpoints, assumptions or guidelines applied to come up with the concrete arrangement of activities. These latter elements are critical not only for informative reasons, but as a medium towards the end of connecting theories and hypotheses to actual practice and analysing the resulting empirical data as a form of inquiry on the validity of theoretical assumptions. This paper delineates the main aspects of a schema for the recording of such design rationales using an ontological approach. The method for the engineering of the schema was based on connecting the definitions provided with an existing large ontological base, thus reusing a large amount of common sense knowledge. Two paradigmatic example positions of the range of aspects that could be covered by the representation language are described as an illustration. The resulting ontological definitions can be used as a foundation for the refinement of theoretical positions and for their comparative assessment. [source]


Principles for sustainability rating of investment funds

BUSINESS STRATEGY AND THE ENVIRONMENT, Issue 1 2005
Thomas Koellner
During the last decade, the idea of sustainable investments hit the market. Investors both private and institutional started to supplement financial considerations with social and ecological ones. Meanwhile the supply of mutual funds in the ,green' investment sector increased enormously. Currently in Europe about 300 mutual funds are available that are managed according to sustainability and social responsibility. Potential investors face the difficulty of keeping track of the various funds and choosing among them based on a reliable comparative assessment. This paper outlines the basic principles and methods on which such a comparative sustainability rating is based. The method was designed to be analogous to rating of the funds financially. The sustainability rating is based on assessment of the research processes in the fund management as well as investigation of the fund portfolio in terms of composition and sustainability performance. It should support investors in their investment choices by offering them a third party view. Copyright © 2005 John Wiley & Sons, Ltd and ERP Environment. [source]


The importance of exposure estimation in the assessment of skin sensitization risk

CONTACT DERMATITIS, Issue 5 2000
Michael K. Robinson
The development of new ingredients and products for the consumer market requires a thorough assessment of their potential for skin sensitization and the possible clinical manifestation of allergic contact dermatitis. The process by which low molecular weight chemicals induce and elicit skin sensitization reactions is complex and dependent on many factors relevant to the ability of the chemical to penetrate the skin, react with protein, and trigger the cell-mediated immune response. These major factors include inherent potency, chemical dose, duration and frequency of exposure, vehicle or product matrix, and occlusion. The fact that a chemical is a contact allergen does not mean that it cannot be formulated into a consumer product at levels well tolerated by most individuals. Many common ingredients (e.g., fragrances, preservatives) are known skin allergens. However, all allergens show dose-response and threshold characteristics. Therefore, one should be able to incorporate these chemicals into products at levels that produce acceptably low incidences of skin sensitization under foreseeable conditions of exposure. The critical exposure determinant for evaluating skin sensitization risk is dose per unit area of skin exposed. Use of this parameter allows for comparative assessments from different types of skin sensitization tests (including cross-species comparisons), and, at least for known potent allergens, there is remarkable similarity in threshold dose/unit area determinations across species. The dose/unit area calculation enables a judgment of the sensitization risk for different product types. This is illustrated using the chemical preservative methylchloroisothiazolinone/methylisothiazolinone (MCI/MI) as a case study. [source]


Observations on the breeding behaviour of the Stripe-breasted tit (Parus fasciiventer) in Bwindi Impenetrable National Park, Uganda

AFRICAN JOURNAL OF ECOLOGY, Issue 2 2010
Jane Yatuha
Abstract The motivation of this study was to investigate some hitherto unknown information on the breeding ecology of the Stripe-breasted Tit (Parus fasciiventer) in Bwindi Impenetrable National Park, south-western Uganda. Parus fasciiventer is one of the least studied and endemic bird species restricted to the montane forests of the Albertine Rift. Regionally, it is classified as near-threatened. The study was carried out around the Institute of Tropical Forest Conservation Ruhija camp and the period of study was from January to June 2003. Data were generated through direct observation at the nest box sites of three active nests. Each of the nest boxes was monitored from the time of nest building to the time the chicks fledged. Results and comparative assessments from this study demonstrate that P. fasciiventer, compared with its temperate congeners like Great Tits (Parus major), Marsh Tits (Parus palustris), Crested Tits (Parus cristatus), Coal Tits (Parus ater) and Blue Tits (Parus caeruleus), raised small broods and had longer nestling period. The findings further revealed that the species is capable of raising more than one brood in a single breeding season and provide further evidence that it is a cooperative breeder. Parents participated equally in raising the young, an indication of pure parenting in the species. Résumé La raison de cette étude était de rechercher certaines informations jusqu'alors inconnues sur l'écologie de la reproduction de la mésange à ventre strié, Parus fasciiventer, dans le Parc National de la Forêt impénétrable de Bwindi, dans le sud-ouest de l'Ouganda. Parus fasciiventer est une des espèces d'oiseaux endémiques les moins étudiées; elle se limite aux forêts de montagne du Rift Albertin. Au niveau régional, elle est classée comme quasi menacée. L'étude s'est réalisée autour du camp de Ruhija de l'Institute of Tropical Forest Conservation de janvier à juin 2003. Les données furent obtenues par des observations directes sur les sites de trois nichoirs actifs. Chaque nid a été suivi depuis sa construction jusqu'à la mue des oisillons. Les résultats et des évaluations comparatives de cette étude ont montré que P. fasciiventer, comparéà ses congénères des régions tempérées comme la mésange charbonnière Parus major, la mésange nonnette Parus palustris, la mésange huppée Parus cristatus, la mésange noire Parus ater et la mésange bleue Parus caeruleus, élevait de plus petites nichées et avait une plus longue durée de nidification. Les résultats ont aussi révélé que cette espèce est capable d'élever plus d'une nichée au cours d'une même saison de reproduction et apportent de nouvelles preuves du fait que c'est une espèce qui pratique la reproduction coopérative. Les parents participaient de façon équitable à l'élevage des jeunes, un signe de parenté directe chez cette espèce. [source]


Experimental determinations of factors affecting the sink rates of baited hooks to minimize seabird mortality in pelagic longline fisheries

AQUATIC CONSERVATION: MARINE AND FRESHWATER ECOSYSTEMS, Issue 6 2010
Graham Robertson
Abstract 1.An experiment was conducted in Australia's pelagic longline fishery to establish a scientific basis for the introduction of line weighting to reduce seabird mortality. The experiment examined the effects of different bait species (blue mackerel, yellow-tail mackerel and squid), bait life status (dead or alive), weight of leaded swivels (60,g, 100,g and 160,g) and leader length (distance between leaded swivel and hooks: 2,m, 3,m and 4,m) on the sink rates of baited hooks from 0,6,m deep. 2.On average, live bait sank much more slowly than dead bait. The sink rates of individual live bait were highly variable: many were <2,m underwater 18,s after deployment, including some on the heaviest swivels, and some were <10,m deep after 120,s. 3.Within the dead bait group, all three swivel weights on 3,m and 4,m leaders sank at similar rates. Initial sink rates (e.g. 0,2,m) were 2,3 times slower than final rates (e.g. 4,6,m) for all combinations of swivel weight and leader length. The fastest initial and final sink rates were associated with heavy swivels placed close to hooks. 4.The results show that (a) compared with dead bait, live bait greatly increases the exposure of baited hooks to seabirds; (b) initial sink rates of dead bait are increased by placing leaded swivels close to hooks and final rates by increasing the weight of the swivels; (c) adding weight to long leaders makes little difference to sink rates; and (d) the small (incremental) changes to swivel weights and leader lengths typically preferred by industry will be difficult to detect at sea and unlikely to substantially reduce seabird mortality. 5.We suggest that experiments designed to reduce seabird mortality from that associated with 60,g swivels and ,3.5,m leaders (the preferred option by industry) should aim to expedite the initial sink rates as well as rates to deeper depths. This objective could be achieved by including branch lines with ,120,g swivels ,2,m in comparative assessments of the effectiveness of line weighting regimes in reducing seabird mortality. Copyright © 2010 John Wiley & Sons, Ltd. [source]