116 research outputs found
CERTIFICATION REPORT: The certification of electrophoretic mobility/zeta potential of silica particles in aqueous solution: ERM-FD306/SRM 1993
This report describes the production of ERM-FD306/SRM 1993, silica particles suspended in a borate buffer, certified for electrophoretic mobility and zeta potential by electrophoretic light scattering (ELS). This material was produced following ISO 17034:2016 and is certified in accordance with ISO Guide 35:2017.
The certified reference material (CRM) was jointly produced by the Directorate F - Health, Consumers and Reference Materials of the European Commissionâs Joint Research Centre (JRC) in Geel (Belgium) and the US National Institute of Standards and Technology (NIST), Gaithersburg (USA). The CRM was produced from a buffer-modified and diluted commercial colloidal silica slurry.
Between-ampoule homogeneity was quantified and stability during dispatch and storage were assessed in accordance with ISO Guide 35:2017. The minimum sample intake for the ELS method was determined from the results and information provided by the laboratories that participated in the interlaboratory comparison (ILC) exercise.
The material was characterised by an interlaboratory comparison between laboratories of demonstrated competence and adhering to ISO/IEC 17025. Technically invalid results were removed but no outlier was eliminated solely on statistical grounds.
Uncertainties of the certified values were calculated in accordance with the Guide to the Expression of Uncertainty in Measurement (GUM) and include uncertainties related to possible inhomogeneity, instability and characterisation.
The material is intended for quality control and assessment of method performance. The method-defined certified values are regarded as reliable estimates of the true values and ERM-FD306/SRM 1993 can therefore be used for calibration purposes. The CRM is available in 25 mL pre-scored amber glass ampoules each containing approximately 25 mL of suspension.JRC.F.6-Reference Material
CERTIFICATION REPORT The certification of electrophoretic mobility/zeta potential of silica particles in aqueous solution: ERM-FD305/SRM 1992
This report describes the production of ERM-FD305/SRM 1992, silica particles suspended in a borate buffer, certified for electrophoretic mobility and zeta potential by electrophoretic light scattering (ELS). This material was produced following ISO 17034:2016 and is certified in accordance with ISO Guide 35:2017.
The certified reference material (CRM) was jointly produced by the Directorate F - Health, Consumers and Reference Materials of the European Commissionâs Joint Research Centre (JRC) in Geel (Belgium) and the US National Institute of Standards and Technology (NIST), Gaithersburg (USA). The CRM was produced from a buffer-modified and diluted commercial colloidal silica slurry.
Between-ampoule homogeneity was quantified and stability during dispatch and storage were assessed in accordance with ISO Guide 35:2017. The minimum sample intake for the ELS method was determined from the results and information provided by the laboratories that participated in the interlaboratory comparison (ILC) exercise.
The material was characterised by an interlaboratory comparison between laboratories of demonstrated competence and adhering to ISO/IEC 17025. Technically invalid results were removed but no outlier was eliminated solely on statistical grounds.
Uncertainties of the certified values were calculated in accordance with the Guide to the Expression of Uncertainty in Measurement (GUM) and include uncertainties related to possible inhomogeneity, instability and characterisation.
The material is intended for quality control and assessment of method performance. The CRM is available in 5 mL pre-scored amber glass ampoules each containing approximately 5 mL of suspension.JRC.F.6-Reference Material
Marketing (as) Rhetoric: paradigms, provocations, and perspectives
In this collection of short, invited essays on the topic of marketing (as) rhetoric we deal with a variety of issues that demonstrate the centrality of rhetoric and rhetorical considerations to the pursuit of marketing scholarship, research and practice. Stephen Brown examines the enduring rhetorical power of the 4Ps; Chris Hackley argues for the critical power of rhetorical orientations in marketing scholarship but cautions us on the need to work harder in conceptually connecting rhetorical theory and modern marketing frameworks; Shelby Hunt explains how rhetorical processes are incorporated in his inductive realist model of theory generation, using one of his most successful publications as an illustration; Charles Marsh demonstrates what Isocratesâ broad rhetorical project has to teach us about the importance of reputation cultivation in modern marketing; Nicholas OâShaughnessy uses an analysis of Trumpâs discourse to argue that political marketing as it is currently conceived is ill-equipped to engage effectively with the rhetorical force of Trumpâs âunmarketingâ; Barbara Phillips uses Vygotskyâs work on imagination to investigate the important of pleasure and play in advertising rhetoric; and finally, David Tonks, who in many ways started it all, reiterates the need for marketers to recognise the strength of the relationship between marketing and persuasion
Contextualizing students' alcohol use perceptions and practices within French culture: an analysis of gender and drinking among sport-science college students
Although research has examined alcohol consumption and sport in a variety of contexts, there is a paucity of research on gender and gender dynamics among French college students. The present study addresses this gap in the literature by examining alcohol use practices by men and women among a non-probability sample of French sport science students from five different universities in Northern France. We utilized both survey data (N = 534) and in-depth qualitative interviews (n = 16) to provide empirical and theoretical insight into a relatively ubiquitous health concern: the culture of intoxication. Qualitative data were based on studentsâ perceptions of their own alcohol use; analysis were framed by theoretical conceptions of gender. Survey results indicate gender differences in alcohol consumption wherein men reported a substantially higher frequency and quantity of alcohol use compared to their female peers. Qualitative findings confirm that male privilege and womenâs concern for safety, masculine embodiment via alcohol use, gendering of alcohol type, and gender conformity pressures shape gender disparities in alcohol use behavior. Our findings also suggest that health education policy and educational programs focused on alcohol-related health risks need to be designed to take into account gender category and gender orientation
Revisiting Primary Particles in Layered Lithium TransitionâMetal Oxides and Their Impact on Structural Degradation
Physical characterization of liposomal drug formulations using multidetector asymmetrical-flow field flow fractionation
Liposomal formulations for the treatment of cancer and other diseases are the most common form of nanotechnology enabled pharmaceuticals (NEPs) submitted for market approval and in clinical application today. The accurate characterization of their physical-chemical properties is a key requirement; in particular, size, size distribution, shape, and physical-chemical stability are key among properties that regulators identify as critical quality attributes. Here we develop and validate an optimized method, based on multi-detector asymmetrical flow field flow fractionation (MD-AF4) to accurately and reproducibly separate liposomal drug formulations into their component populations and to characterize their associated size and size distribution, whether monomodal or polymodal in nature. In addition, the results show that the method is suitable to measure liposomes in the presence of serum proteins and can yield information on the shape and physical stability of the structures. The optimized MD-AF4 based method has been validated across different instrument platforms, three laboratories, and multiple drug formulations following a comprehensive analysis of factors that influence the fractionation
process and subsequent physical characterization. Interlaboratory reproducibility and intra-laboratory precision were evaluated, identifying sources of bias and establishing criteria for the acceptance of results. This method meets a documented high priority need in regulatory science as applied to NEPs such as Doxil and can be adapted to the measurement of other NEP forms (such as lipid nanoparticle therapeutics) with some modifications. Overall, this method will help speed up development of NEPS, and facilitate their regulatory review, ultimately leading to faster translation of innovative concepts from the bench to the clinic. Additionally, the approach used in this work (based on international collaboration between leading non-regulatory institutions) can be replicated to address other identified gaps in the analytical characterization of various classes of NEPs. Finally, a plan exists to pursue more extended interlaboratory validation studies to advance this method to a consensus international standard.JRC.F.2-Consumer Products Safet
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