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Potential Methods (potential + methods)
Selected AbstractsA review of potential methods of determining critical effect size for designing environmental monitoring programs,ENVIRONMENTAL TOXICOLOGY & CHEMISTRY, Issue 7 2009Kelly R. Munkittrick Abstract The effective design of field studies requires that sample size requirements be estimated for important endpoints before conducting assessments. This a priori calculation of sample size requires initial estimates for the variability of the endpoints of interest, decisions regarding significance levels and the power desired, and identification of an effect size to be detected. Although many programs have called for use of critical effect sizes (CES) in the design of monitoring programs, few attempts have been made to define them. This paper reviews approaches that have been or could be used to set specific CES. The ideal method for setting CES would be to define the level of protection that prevents ecologically relevant impacts and to set a warning level of change that would be more sensitive than that CES level to provide a margin of safety; however, few examples of this approach being applied exist. Program-specific CES could be developed through the use of numbers based on regulatory or detection limits, a number defined through stakeholder negotiation, estimates of the ranges of reference data, or calculation from the distribution of data using frequency plots or multivariate techniques. The CES that have been defined often are consistent with a CES of approximately 25%, or two standard deviations, for many biological or ecological monitoring endpoints, and this value appears to be reasonable for use in a wide variety of monitoring programs and with a wide variety of endpoints. [source] An Innovative Strategy for Conducting Clinical Research: The Academic Associate ProgramACADEMIC EMERGENCY MEDICINE, Issue 2 2002Judd E. Hollander MD Performance of high-quality clinical research usually requires procurement of substantial funding to support and sustain the research infrastructure. The authors have developed a program to support a research infrastructure that minimizes financial start-up costs and maximizes productivity of clinical-educator faculty with limited protected time. The program integrates clinical research with undergraduate education. The authors report the experience with the academic associate program at two academic institutions. They describe the program, provide measures of program success, and discuss potential methods for other institutions to initiate similar programs. Similar programs can be developed in a variety of outpatient and inpatient settings allowing the performance of high-quality clinical research in a time-efficient and cost-effective manner. [source] ABCG2 (BCRP) expression in normal and malignant hematopoietic cellsHEMATOLOGICAL ONCOLOGY, Issue 3 2003Brian L. Abbott Abstract ABCG2 (BCRP) is a member of the ATP-binding cassette (ABC) family of cell surface transport proteins. ABCG2 expression occurs in a variety of normal tissues, and is relatively limited to primitive stem cells. ABCG2 expression is associated with the side population (SP) phenotype of Hoechst 33342 efflux. The substrate profile of ABCG2 includes the antineoplastic drugs primarily targeting topoisomerases, including anthracyclines and camptothecins. More recently, pheophorbide, a chlorophyll-breakdown product, and protoporhyrin IX have been described as ABCG2 substrates, perhaps indicating a physiologic role of cytoprotection of primitive cells. Also, mice lacking ABCG2 expression have no intrinsic stem cell defects, although there is a remarkable increase in toxicity with antineoplastic drugs that are ABCG2 substrates, and also a photosensitivity resembling protoporphyria. Like other members of the ABC family, such as MDR1 and MRP1, ABCG2 is expressed in a variety of malignancies. Despite numerous reports of ABCG2 expression in AML, there is little evidence that ABCG2 expression is correlated with an adverse clinical outcome. This review will focus on the potential usefulness of ABCG2 as a marker primitive stem cells and possible physiologic roles of ABCG2 in protection of primitive stem cell populations, and potential methods of overcoming ABCG2-associated drug resistance in anticancer therapy. Copyright © 2003 John Wiley & Sons, Ltd. [source] Geothermal-based hydrogen production using thermochemical and hybrid cycles: A review and analysisINTERNATIONAL JOURNAL OF ENERGY RESEARCH, Issue 9 2010M. Tolga Balta Abstract Geothermal-based hydrogen production, which basically uses geothermal energy for hydrogen production, appears to be an environmentally conscious and sustainable option for the countries with abundant geothermal energy resources. In this study, four potential methods are identified and proposed for geothermal-based hydrogen production, namely: (i) direct production of hydrogen from the geothermal steam, (ii) through conventional water electrolysis using the electricity generated through geothermal power plant, (iii) by using both geothermal heat and electricity for high temperature steam electrolysis and/or hybrid processes, and (iv) by using the heat available from geothermal resource in thermochemical processes. Nowadays, most researches are focused on high-temperature electrolysis and thermochemical processes. Here we essentially discuss some potential low-temperature thermochemical and hybrid cycles for geothermal-based hydrogen production, due to their wider practicality, and examine them as a sustainable option for hydrogen production using geothermal heat. We also assess their thermodynamic performance through energy and exergy efficiencies. The results show that these cycles have good potential and attractive overall system efficiencies over 50% based on a complete reaction approach. The copper-chlorine cycle is identified as a highly promising cycle for geothermal-hydrogen production. Copyright © 2009 John Wiley & Sons, Ltd. [source] Assessment and validation of bronchodilation using the interrupter technique in preschool children,PEDIATRIC PULMONOLOGY, Issue 7 2010Laura Mele Abstract Objective To determine and validate a cut-off value for bronchodilation using the interrupter resistance (Rint) in preschool children. Patients and Methods Rint was measured in 60 healthy children (age range 2.7,6.4 years) before and after salbutamol inhalation (200,µg). Four potential methods for assessing BDR were evaluated: percent change from baseline, percent change of predicted values, absolute change in Rint, and change in Z-score. These cut-off values, determined as the fifth percentile of the healthy group, were applied to children referred for the assessment of recurrent wheezing, classified on the basis of acute symptoms and/or abnormal chest examination into symptomatic (n,=,60, age range 2.9,6.1 years) and asymptomatic (n,=,60, age range 2.5,5.7 years) groups. Results The cut-off values for bronchodilation calculated in healthy children were: ,32% baseline; ,33% predicted; ,0.26,kPa L,1 sec; and ,1.25 Z-scores. Assessing BDR in children with a history of wheezing by either a decrease in absolute Rint or a decrease in Z-score gave sensitivity, specificity, negative predictive value, and positive predictive value all >80% for detecting children with current respiratory symptoms. Conclusions Both a decrease in Rint ,0.26,kPa L,1 sec and a decrease in Z-score of ,1.25 are appropriate for assessing BDR in preschool children with a history of recurrent wheezing. As Z-score is a more general solution, we recommend using a change in Z-score to determine BDR in preschool children. Further longitudinal studies will be required to determine the clinical utility of measuring BDR in managing lung disease in such children. Pediatr Pulmonol. 2010; 45:633,638. © 2010 Wiley-Liss, Inc. [source] Ab-initio investigation of thermoactivated directional transport of hydrogen molecules inside narrow carbon nanotubesPHYSICA STATUS SOLIDI (B) BASIC SOLID STATE PHYSICS, Issue 11-12 2009A. S. Fedorov Abstract Using the pseudopotential DFT and the empirical potential methods we calculate the potential acting to the hydrogen molecules in narrow single-wall carbon nanotubes (SWCNT) (6,0),(7,0) and (3,3). The potential forms a goffered potential surface and can be approximated as . We show that in these SWCNTs transport of molecules is given mainly by thermoactivated hoppings between minima of the periodic potential along the tube axis. Taking into account that hydrogen density distribution inside nanotube is stationary and assuming the temperature is changed linearly along the SWCNT length we show that the H2 density is sufficiently variated, especially for the case of (6,0)SWCNT where the density on both SWCNT ends are different at , 30 times when the temperature is changed along the SWCNTf rom 300K to 1200K. Suppose that H2 molecules can penetrate in the both open SWCNT ends, the molecules would move in the direction of the temperature decreasing. This effect may be used potentially to build up a molecular pump driven by the temperature gradient along narrow nanotube. [source] Public Health in the Emergency Department: Overcoming Barriers to Implementation and DisseminationACADEMIC EMERGENCY MEDICINE, Issue 11 2009Mary Pat McKay MD Abstract This article is the outcome of a consensus building workshop entitled, "Overcoming Barriers to Implementation and Dissemination" convened at the 2009 Academic Emergency Medicine Consensus Conference, ,,Public Health in the ED: Surveillance, Screening, and Intervention." The participants were asked to address potential methods for overcoming barriers to the dissemination and implementation in the emergency department (ED) of evidenced-based practices to improve public health. The panel discussed three broad areas of interest including methods for disseminating evidence-based practices, barriers encountered during the process of implementation, and the importance of involvement in activities outside the ED including engagement in policy development and improvement. Four recommendations were discussed in detail and consensus was reached. The recommendations included 1) researchers and advocates should disseminate findings through multiple forums beyond peer-reviewed publications when an ED-based public health intervention has enough evidence to support integration into the routine practice of emergency care; 2) local barriers to implementation of public health interventions should be recognized and well understood from multiple perspectives prior to implementation; 3) innovation must be put into place and adapted based on local institutional context and culture as barriers and the best methods for overcoming them will vary across institutions; and 4) use of legislation, regulation, and incentives outside of the ED should support and strengthen ED-based interventions. For each area of interest, research dimensions to extend the current understanding of methods for effectively and efficiently implementing evidence-based public health interventions in the ED were discussed and consensus was achieved. [source] New insights into pigmentary pathways and skin cancerBRITISH JOURNAL OF DERMATOLOGY, Issue 1 2010A.J. Miller Summary The ability of cells to respond to and to mitigate environmental stress is crucial for their survival. Constitutive and facultative pigmentation have evolved in order for human skin to contend with high levels of terrestrial ultraviolet radiation (UVR). When this melanin ,shield' is compromised, individuals are exposed to increased skin cancer risk. The purpose of this review is to discuss new insights into the genetic basis of phenotypic risk factors for skin cancer, their connection to pigmentation and tanning, the precise molecular connections linking UVR to the tanning response, and potential methods of modulating pigmentation that avoid genotoxic damage. Highly translational implications of this research include a scientific basis on which to counsel patients regarding the carcinogenicity of UVR exposure related to tanning and potential new tanning agents that may actually protect against skin cancer by circumventing the need for UVR exposure. [source] | ||||||||||