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Useful Role (useful + role)
Selected AbstractsCan Metal,Organic Framework Materials Play a Useful Role in Large-Scale Carbon Dioxide Separations?CHEMSUSCHEM CHEMISTRY AND SUSTAINABILITY, ENERGY & MATERIALS, Issue 8 2010Seda Keskin Dr. Abstract Metal,organic frameworks (MOFs) are a fascinating class of crystalline nanoporous materials that can be synthesized with a diverse range of pore dimensions, topologies, and chemical functionality. As with other well-known nanoporous materials, such as activated carbon and zeolites, MOFs have potential uses in a range of chemical separation applications because of the possibility of selective adsorption and diffusion of molecules in their pores. We review the current state of knowledge surrounding the possibility of using MOFs in large-scale carbon dioxide separations. There are reasons to be optimistic that MOFs may make useful contributions to this important problem, but there are several critical issues for which only very limited information is available. By identifying these issues, we provide what we hope is a path forward to definitively answering the question posed in our title. [source] Differentiation and integration: guiding principles for analyzing cognitive changeDEVELOPMENTAL SCIENCE, Issue 4 2008Robert S. Siegler Differentiation and integration played large roles within classic developmental theories but have been relegated to obscurity within contemporary theories. However, they may have a useful role to play in modern theories as well, if conceptualized as guiding principles for analyzing change rather than as real-time mechanisms. In the present study, we used this perspective to examine which rules children use, the order in which the rules emerge, and the effectiveness of instruction on water displacement problems. We found that children used systematic rules to solve such problems, and that the rules progress from undifferentiated to differentiated forms and toward increasingly accurate integration of the differentiated variables. Asking children to explain both why correct answers were correct and why incorrect answers were incorrect proved more effective than only requesting explanations of correct answers, which was more effective than just receiving feedback on the correctness of answers. Requests for explanations appeared to operate through helping children notice potential explanatory variables, formulate more advanced rules, and generalize the rules to novel problems. [source] Factors influencing the scope and quality of science and management decisionsFISH AND FISHERIES, Issue 1 2002(The good, the bad, the ugly) Abstract The lecture traces the historical path to overfishing of the world's fish and shellfish stocks, and provides an assessment of marine fish resources in the later half of the 1990s. The basis of overfishing as noted by various fishery scientists is reviewed. Four factors, including institutional paralysis, the rapidity of technological developments, uncertainty of science, and the inability to monitor and enforce regulations are identified as the major problems leading to overfishing. The failure of the world community to deal with extensive overfishing, appears to have motivated managers and scientists to promote a new fishery management paradigm that focuses on a broader set of problems resulting from fishing, and establishes a more conservative decision-making process founded on precautionary principle and uncertainty. The author feels that the evolving paradigm will result in the rebuilding of a number of stocks in the United States, but is less certain of its adoption on a global scale, and whether or not science will play a more useful role in fisheries management. It is noted that the support for fisheries science and the status of fisheries have followed opposite courses. Over the past half century marine science has boomed, diversified and become intellectually and materially enriched, while the number of overfished stocks and ecological disasters has increased. Looking ahead it is expected that fisheries management will move into a more conservative era. The focus of fisheries has moved from full use of ocean resources to establishing yields that take into account the impacts of fisheries on target and non-target species and the ecosystem in general. Although there has been wide-spread abuse in the use of the world's fishery resources and condemnation of the fishing industries, the author feels that the government institutions must bear the primary responsibility for the historical course of fishery management and its failure. [source] Imaging and intervention of retroperitoneal fibrosisJOURNAL OF MEDICAL IMAGING AND RADIATION ONCOLOGY, Issue 1 2007T Geoghegan Summary Retroperitoneal fibrosis is a rare condition characterized by the development of fibrous plaques in the retroperitoneal space. The fibrous plaques characteristically arise distal to the bifurcation of the abdominal aorta and progress to encase the iliac vessels distally and are defined by the associated encasement of one or both ureters. Imaging plays an important role in not only establishing the diagnosis, but also in monitoring disease progression. Historically, the radiological diagnosis was made predominantly by intravenous urography and retrograde pyelography. More recently, advances in cross-sectional imaging with ultrasound and contrast-enhanced CT have allowed for a more precise diagnosis as well as helping to accurately define the extent of the disease. At our institution, we have found ultra-fast MRI to also play a useful role in establishing the diagnosis. In particular, magnetic resonance urography using HASTE (half Fourier-acquired single shot turbo spin-echo) sequences allow a safe alternative to intravenous urography, particularly in patients with poor renal function. The purpose of this article is to describe the role of the various imaging methods available to the radiologist and to emphasize the important role that the interventional radiologist now plays, not only in obtaining tissue for diagnosis, but also in providing treatment of the disease by percutaneous nephrostomy drainage and subsequent stent placement in select cases. [source] Pro,con debate: is codeine a drug that still has a useful role in pediatric practice?PEDIATRIC ANESTHESIA, Issue 2 2010DCHRCP, FRCA, MICHAEL TREMLETT BM First page of article [source] Procyanidins extracted from the lotus seedpod ameliorate scopolamine-induced memory impairment in micePHYTOTHERAPY RESEARCH, Issue 12 2009Jiqu Xu Abstract The major purpose of this study was to determine the effect of procyanidins extracted from the lotus seedpod (LSPC) on the learning and memory impairments induced by scopolamine (1 mg/kg, i.p.) in mice. The capacities of memory and learning were evaluated by the Morris water maze and the step-down avoidance test. LSPC (50, 100, 150 mg/kg BW, p.o.) significantly reversed scopolamine-induced learning and memory impairments in the Morris water maze test, as evaluated by shortened escape latency and swimming distance. In the step-down avoidance test, LSPC (50, 100, 150 mg/kg BW, p.o.) treatment significantly reduced the number of errors and shortened latency compared with that of scopolamine. In addition, LSPC was also found to inhibit acetyl cholinesterase (AChE) activity. These results of this study suggest that LSPC may play a useful role in the treatment of cognitive impairment caused by AD and aging. Copyright © 2009 John Wiley & Sons, Ltd. [source] Millimetre-scale bubble-like dielectric elastomer actuatorsPOLYMER INTERNATIONAL, Issue 3 2010Federico Carpi Abstract Hydrostatic coupling has recently been reported as a means to improve the versatility and safety of electromechanical actuators based on dielectric elastomers (DEs). Hydrostatically coupled DE actuators rely on an incompressible fluid that mechanically couples a DE-based active part to a passive part interfaced to the load. The work reported here was aimed at developing millimetre-scale bubble-like versions of such transducers. Silicone-made oil-filled actuators were manufactured as both single units and arrays of parallel elements. Bubbles had a base diameter of 6 mm and were driven up to a voltage of 2.25 kV, applied across a silicone film with a thickness of 42 µm. Active relative displacements and stresses up to 18% and 2.2 kPa, respectively, were recorded with static driving. Dynamic investigations reported a ,3 dB bandwidth of the order of 100 Hz and a resonance frequency of about 250 Hz. Millimetre-scale hydrostatically coupled DE actuators might play a useful role in several fields of application. Among them, we are currently exploring novel tactile displays and cutaneous stimulators, made of wearable, distributed and flexible devices. Although further miniaturization is required for high-resolution uses, this technology holds promise to properly combine performance with safe and compliant interfaces with users, low specific weight, no acoustic noise and low cost. Copyright © 2009 Society of Chemical Industry [source] Imagining a Shared State in Palestine,IsraelANTIPODE, Issue 1 2010Elizabeth Mavroudi Abstract:, There has been much deliberation over future solutions to the Palestinian,Israeli impasse. These invariably revolve around the two-state solution. However, some have argued that a one-state solution would be preferable because it stresses the need to imagine Palestinians and Israelis as connected rather than as separate. This article examines notions of a one-state solution and highlights the useful role that geographers can play in discussing such notions. In particular, it focuses on the need to re-think relationships between citizenship, national identity and the nation-state in order to emphasise the importance of shared pasts, presents and futures in the region. The article also outlines the relevance of postcolonial, diasporic and transnational theories to geographical discussions on the one-state solution and concludes that the use of such theories potentially allows a more hopeful exploration of the complex identities, lives and performances of people as they struggle to negotiate contested spaces and places. [source] Comparing performances of logistic regression and neural networks for predicting melatonin excretion patterns in the rat exposed to ELF magnetic fieldsBIOELECTROMAGNETICS, Issue 2 2010Samad Jahandideh Abstract Various studies have been reported on the bioeffects of magnetic field exposure; however, no consensus or guideline is available for experimental designs relating to exposure conditions as yet. In this study, logistic regression (LR) and artificial neural networks (ANNs) were used in order to analyze and predict the melatonin excretion patterns in the rat exposed to extremely low frequency magnetic fields (ELF-MF). Subsequently, on a database containing 33 experiments, performances of LR and ANNs were compared through resubstitution and jackknife tests. Predictor variables were more effective parameters and included frequency, polarization, exposure duration, and strength of magnetic fields. Also, five performance measures including accuracy, sensitivity, specificity, Matthew's Correlation Coefficient (MCC) and normalized percentage, better than random (S) were used to evaluate the performance of models. The LR as a conventional model obtained poor prediction performance. Nonetheless, LR distinguished the duration of magnetic fields as a statistically significant parameter. Also, horizontal polarization of magnetic fields with the highest logit coefficient (or parameter estimate) with negative sign was found to be the strongest indicator for experimental designs relating to exposure conditions. This means that each experiment with horizontal polarization of magnetic fields has a higher probability to result in "not changed melatonin level" pattern. On the other hand, ANNs, a more powerful model which has not been introduced in predicting melatonin excretion patterns in the rat exposed to ELF-MF, showed high performance measure values and higher reliability, especially obtaining 0.55 value of MCC through jackknife tests. Obtained results showed that such predictor models are promising and may play a useful role in defining guidelines for experimental designs relating to exposure conditions. In conclusion, analysis of the bioelectromagnetic data could result in finding a relationship between electromagnetic fields and different biological processes. Bioelectromagnetics 31:164,171, 2010. © 2009 Wiley-Liss, Inc. [source] The molecular genetics of the genodermatoses: progress to date and future directionsBRITISH JOURNAL OF DERMATOLOGY, Issue 1 2003A.D. Irvine Summary The Human Genome Mapping Project and allied rapid advances in genetic technology over the past decade have facilitated accurate association of allelic variations in several genes with specific skin phenotypes. Currently the genetic bases of the majority of the more common genodermatoses have been elucidated. In scientific terms this work has been extraordinarily successful and has yielded many new biological insights. These advances, although exciting, have yet to be translated into direct benefit for patients with these diseases. Genetic counselling has been greatly aided by gene identification, by the better understanding of genotype,phenotype correlation and by the disclosure of unexpected genetic mechanisms in some families. Knowledge of the molecular basis of these disorders has also been vital in enabling DNA-based prenatal diagnosis in several conditions and DNA-based preimplantation diagnosis has been used in a selected few. While this successful period of gene mapping is now nearing completion, progress towards the next goal, that of developing therapeutic strategies based on the knowledge of these underlying genetic mechanisms, has proven frustratingly slow. Despite the ready access to the skin compared with solid internal organs, the challenges of cutaneous gene therapy are legion and many technical issues need to be surmounted to enable gene replacement or modification of gene expression to have a useful role in these disorders. In this article we make a comprehensive review of progress to date in gene identification, genotype,phenotype correlation, prenatal diagnosis and cutaneous gene therapy, and we examine future directions for research in this field. [source] | ||||||||||