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Potential Replacement (potential + replacement)
Selected AbstractsDirect and indirect effects of a potential aquatic contaminant on grazer,algae interactionsENVIRONMENTAL TOXICOLOGY & CHEMISTRY, Issue 2 2009Michelle A. Evans-White Abstract Contaminants have direct, harmful effects across multiple ecological scales, including the individual, the community, and the ecosystem levels. Less, however, is known about how indirect effects of contaminants on consumer physiology or behavior might alter community interactions or ecosystem processes. We examined whether a potential aquatic contaminant, an ionic liquid, can indirectly alter benthic algal biomass and primary production through direct effects on herbivorous snails. Ionic liquids are nonvolatile organic salts being considered as an environmentally friendly potential replacement for volatile organic compounds in industry. In two greenhouse experiments, we factorially crossed four concentrations of 1-N-butyl-3-methylimidazolium bromide (bmimBr; experiment 1: 0 or 10 mg/L; experiment 2: 0, 1, or 100 mg/L) with the presence or absence of the snail Physa acuta in aquatic mesocosms. Experimental results were weighted by their respective control (no bmimBr or P. acuta) and combined for statistical analysis. When both bmimBr and snails were present, chlorophyll a abundance and algal biovolume were higher than would be expected if both factors acted additively. In addition, snail growth rates, relative to those of controls, declined by 41 to 101% at 10 and 100 mg/L of bmimBr. Taken together, these two results suggest that snails were less efficient grazers in the presence of bmimBr, resulting in release of algae from the grazer control. Snails stimulated periphyton primary production in the absence, but not in the presence, of bmimBr, suggesting that bmimBr also can indirectly alter ecosystem function. These findings suggest that sublethal contaminant levels can negatively impact communities and ecosystem processes via complex interactions, and they provide baseline information regarding the potential effects of an emergent industrial chemical on aquatic systems. [source] Activated B cells modified by electroporation of multiple mRNAs encoding immune stimulatory molecules are comparable to mature dendritic cells in inducing in vitro antigen-specific T-cell responsesIMMUNOLOGY, Issue 2 2008Jaewoo Lee Summary Ex-vivo -activated B cells are an alternative source of antigen-presenting cells (APCs) and a potential replacement for dendritic cells (DCs) in immunotherapy. However, the ability of ex-vivo -activated B cells to function as potent APCs has been a concern, especially when compared to DCs. Our study investigated whether modification of activated B cells with immune stimulatory molecules could enhance the ability of activated B cells to stimulate T cells. We show that murine splenic B cells, activated with a combination of Toll-like receptor agonist and agonistic anti-CD40, stimulated antigen-specific CD8+ T cells more efficiently than cells activated with Toll-like receptor agonist or anti-CD40 alone, probably by down-regulation of the immune regulatory cytokine interleukin-10 (IL-10). However, the activated B cells were still poor T-cell stimulators compared to mature DCs. Therefore, we modified the activated B cells by simultaneous electroporation of multiple messenger RNAs encoding costimulatory molecules (OX40L and 4-1BBL), cytokines (IL-12p35 and IL-12p40) and antigen. We found that de novo expression or overexpression of OX40L, 4-1BBL and IL-12p70 on activated B cells synergistically enhanced proliferation as well as IL-2 and interferon-, production by CD8+ T cells. Furthermore, the RNA-modified activated B cells induced antigen-specific cytotoxic T lymphocyte responses as efficiently as mature DCs in vitro. Unexpectedly, modified activated B cells were inferior to mature DCs at in vivo induction of CD8+ T-cell responses. In summary, activated B cells modified to express immune stimulatory molecules are a potent alternative to DCs in immunotherapy. [source] A collaborative study to establish the 7th International Standard for Factor VIII ConcentrateJOURNAL OF THROMBOSIS AND HAEMOSTASIS, Issue 1 2005S. Raut Summary., A candidate concentrate, preparation N (99/678), was assayed and calibrated, as a potential replacement, against four established factor (F) VIII concentrate standards: the current WHO 6th International Standard (IS) (97/616), the previous 5th IS (88/640), the Mega 1 standard and Ph. Eur. BRP Batch 2 standard, in a collaborative study involving 38 laboratories. All laboratories were instructed to use the ISTH/SSC recommendations, including predilution of concentrates in FVIII-deficient plasma. Several laboratories performed more than one assay method and altogether there were 27 sets of assays with the one-stage method, 31 with the chromogenic method, and 18 with both methods. There was good agreement between laboratories using each of the two methods for comparison of preparation N against the four established standards, with overall potencies by one-stage and chromogenic methods differing only by less than 2%. However, there were significant differences in potencies relative to the different standards, ranging from 10.1 IU per ampoule against the Ph. Eur.BRP2 to 11.4 against the WHO 6th IS. Accelerated degradation studies showed that the proposed standard is very stable, with a predicted loss of activity per year of less than 0.001% at the recommended storage temperature of ,20 °C. Various options for potency of preparation N were considered by the participants and by members of the ISTH/SSC FVIII/FIX Subcommittee. In November 2003, preparation N (NIBSC 99/678) was proposed to and accepted by the Expert Committee on Biological Standardization of the World Health Organization to be the 7th International Standard for Factor VIII Concentrate with an assigned potency of 11.0 IU per ampoule. [source] Potential of laparoscopic ultrasonography as an alternative to operative cholangiography in the detection of bile duct stonesBRITISH JOURNAL OF SURGERY (NOW INCLUDES EUROPEAN JOURNAL OF SURGERY), Issue 1 2001S. E. Tranter Background: Intraoperative cholangiography (IOC) is time consuming, requires radiation and sometimes fails. In contrast, laparoscopic ultrasonography (LUS) is a comparatively quick, safe and non-invasive technique. The aim of this study was to assess the potential of LUS as an alternative to IOC. Methods: LUS was performed on 367 patients undergoing laparoscopic cholecystectomy. Laparoscopic duct exploration was performed in the presence of duct stones. Data were collected prospectively. The presence or absence and number of duct stones detected by LUS were recorded. The maximum bile duct diameter determined by LUS was compared with a preoperative ultrasonographic measurement according to age and the presence of duct stones. The final arbiter was the demonstration of stones removed at laparoscopic duct exploration (59 patients) or subsequently by endoscopic retrograde cholangiopancreatography (two patients). Results: LUS visualized the CBD in 99 per cent of patients and the common hepatic duct in 92 per cent. It identified stones in 56 of the 61 patients with duct stones. No stones were demonstrated in the remaining 306 patients (sensitivity 92 per cent, specificity 100 per cent, positive predictive value 100 per cent, negative predictive value 98 per cent). LUS underestimated the total number of stones in 18 per cent of patients with common duct stones. The mean common bile duct diameter was 5·0 mm before operation and 5·9 mm during the procedure in patients without duct stones, rising significantly to a mean of 9·2 mm before operation and 11·2 mm at LUS in those with duct stones (P < 0·0001). Conclusion: The combination of the demonstration of duct stones and bile duct diameter measurement makes LUS a potential replacement for IOC. Improved demonstration of the common hepatic duct would be advantageous. © 2001 British Journal of Surgery Society Ltd [source] Microwave-Assisted Combustion Synthesis of Tantalum Nitride in a Fluidized BedJOURNAL OF THE AMERICAN CERAMIC SOCIETY, Issue 2 2003Akhil Jain Combustion synthesis experiments in a fluidized bed have been conducted using nitrogen as the fluidizing gas for the formation of transition-metal nitrides that are potential replacements for traditional hydrodenitrogenation and hydrodesulfurization catalysts. The microwave-assisted ignition of reaction has been investigated for its potential to produce nitride overlayers on two different sizes of tantalum particle substrates. Various characterization techniques,X-ray diffractometry, energy dispersive spectroscopy, scanning electron microscopy, and high-resolution transmission electron microscopy,have been used to study the presence of nitride overlayers. The results indicate that microwave assistance can permit controlled formation of tantalum nitride (Ta2N) overlayers. [source] Reactivity of alkylated phosphorothionates with steel: a tribological and surface-analytical studyLUBRICATION SCIENCE, Issue 2 2008Roman Heuberger Abstract Phosphorothionates are anti-wear lubricant additives and potential replacements for zinc dialkyldithiophosphates. In this study, ball-on-disc tests have been carried out combinatorially under extreme pressure (EP) conditions (100,350,MPa at 10,N load). The tests were performed in oil containing triphenyl phosphorothionates substituted with alkyl chains of different lengths. Imaging, small-area and angle-resolved X-ray photoelectron spectroscopy were performed following the tribotest to probe the modification, removal and growth of the surface film. The films were composed, depending on the test conditions, of (i) iron phosphate, (ii) iron phosphates with sulphates or (iii) a mixture of iron phosphates with sulphides and sulphates. With increasing load, the dimensional wear coefficients decreased. Upon increasing temperature from 30 to 150°C, the wear became more severe. These findings suggest the formation of a tribochemical film with some EP performance, despite the severe tribological test conditions applied in this work. Copyright © 2008 John Wiley & Sons, Ltd. [source] 15N NMR spectroscopy as a method for comparing the rates of imidization of several diamines,POLYMER COMPOSITES, Issue 6 2006James C. Johnston The relative rates of the conversion of amide-acid to imide were measured for a series or aromatic diamines that have been identified as potential replacements for 4,4,-methylene dianiline (MDA) in high-temperature polyimides and polymer composites. These rates were compared with the 15N NMR resonances of the unreacted amines. The initial rates of imidization track with the difference in chemical shift between the amine nitrogens in MDA and those in the subject diamines. This comparison demonstrated that 15N NMR spectroscopy is appropriate for the rapid screening of candidate diamines to determine their reactivity relative to MDA, and can serve to provide guidance to the process of creating the time,temperature profiles used in processing these materials into polymer matrix composites. POLYM. COMPOS. 27:723,729, 2006. © 2006 Society of Plastics Engineers [source] | |||||||||||||