ABSTRACT
In this paper we report quantitative measurements of the imaging performance for the current generation of hybrid pixel detector, Medipix3, used as a direct electron detector. We have measured the modulation transfer function and detective quantum efficiency at beam energies of 60 and 80keV. In single pixel mode, energy threshold values can be chosen to maximize either the modulation transfer function or the detective quantum efficiency, obtaining values near to, or exceeding those for a theoretical detector with square pixels. The Medipix3 charge summing mode delivers simultaneous, high values of both modulation transfer function and detective quantum efficiency. We have also characterized the detector response to single electron events and describe an empirical model that predicts the detector modulation transfer function and detective quantum efficiency based on energy threshold. Exemplifying our findings we demonstrate the Medipix3 imaging performance recording a fully exposed electron diffraction pattern at 24-bit depth together with images in single pixel and charge summing modes. Our findings highlight that for transmission electron microscopy performed at low energies (energies <100keV) thick hybrid pixel detectors provide an advantageous architecture for direct electron imaging.
ABSTRACT
A database has been established that contains confidential information, together with publicly available data, on various aspects of the development of 1106 new chemical entities and biological compounds (including products of biotechnology) first marketed as medicines since 1970 on one or more of 20 major international markets. These data have been used to examine the performance of the European, U.S., and Japanese pharmaceutical industries by examining the numbers and types of new medicines reaching the marketplace from 1970 to 1992 and the companies responsible for introducing them. Although the European marketing companies dominate in total numbers first marketed over this period, there has been a significant decline in their annual output. In contrast, the Japanese companies have shown a significant increase in the number of new compounds marketed annually. However, European marketing companies remain the most successful in terms of sales because they are responsible for first marketing approximately 50% of the top 50 products by international sales in 1992. The main therapeutic areas of output by all three regions have remained relatively unchanged over the 23-year period: cardiovascular system (21%), nervous system (18%), and anti-infectives (16%). This article provides insight into the changing status of the international pharmaceutical industry over the last 23 years in terms of output from research and development.
Subject(s)
Databases, Factual , Drugs, Investigational , Pharmaceutical Preparations , Drug Industry , Europe , Japan , United StatesSubject(s)
Birth Weight/physiology , Diet , Fishes , Pregnancy/physiology , Adult , Animals , Body Height , Female , Gestational Age , Humans , Infant, Newborn , Male , Maternal Age , Scotland , SmokingSubject(s)
Peer Review , Australia , Confidentiality , Education , Hospital Administration , Humans , Models, Theoretical , Outcome and Process Assessment, Health Care , Quality Assurance, Health Care/legislation & jurisprudence , Quality Assurance, Health Care/organization & administration , United StatesABSTRACT
In recent studies in this laboratory employing normal hydropenic rats we have demonstrated that the reduction in absolute proximal reabsorption that attends the experimental reduction of single nephron glomerular filtration rate (SNGFR) (glomerulotubular balance) is mediated, at least in part, by the accompanying decline in postglomerular vascular protein concentration, and therefore, postglomerular colloid osmotic pressure (piEA). The present study was undertaken to define the quantitative contribution of these changes in piEA to the changes in absolute proximal reabsorption measured under these conditions. A protocol was employed which enabled us to examine the effects on absolute proximal reabsorption of reductions in filtered load brought about under conditions in which piEA remained essentially unchanged. Thus, after partial aortic constriction in 16 plasma-loaded rats, near constancy of piEA was observed in 10 (a change in efferent arteriolar protein concentration of 0.4 g/100 ml or less) and in these, uniform reductions in SNGFR averaging 16.7 nl/min were attended by reductions in absolute proximal reabsorption averaging only 1.7 nl/min, or 7% of preconstriction values. These findings, taken together with previous observations from this laboratory, suggest that the proximal reabsorptive adjustment that characterizes glomerulotubular balance in the rat is markedly blunted when changes in piEA are prevented. In the remaining six rats, a mean reduction in filtered load comparable to that observed in the above group was attended by slightly to moderately greater reductions in efferent arteriolar protein concentration, thereby fulfilling less well the stated aim of this study. Nevertheless, in accord with the above conclusion, these relatively greater reductions in piEA were accompanied by correspondingly greater reductions in absolute proximal reabsorption.
