9,061 research outputs found
Raman spectroscopy for the in-line polymer-drug quantification and solid state characterization during a pharmaceutical hot-melt extrusion process
A Killing Disease Epidemic Among Displaced Sudanese Population Identified as Visceral Leishmaniasis.
A fatal disease epidemic affected the Bentiu area in southern Sudan and led to a mass migration of the Nuer tribe searching for treatment. The initially available information revealed a high mortality rate due to a possible occurrence of tuberculosis, malaria, enteric fever or visceral leishmaniasis (VL). Serological screening of 53 of the most severely affected patients in an enzyme-linked immunosorbent assay (ELISA) or an improved direct agglutination test (DAT) revealed positivity for VL. In 39 of those patients, diagnosis was confirmed by identification of Leishmania donovani amastigotes in lymph node or bone-marrow aspirates. In a total of 2714 patients observed, 1195 (44.0%) had clinical symptoms suggesting VL: DAT positive titers (1:3200-greater than or equal to 1:12800) were obtained in 654 (24.1%), of whom 325 were confirmed parasitologically. Forty-two VL cases died before or during treatment, giving a mortality rate of 6.4%. Among the intercurrent infections diagnosed in the VL population (654), respiratory involvements (31.7%) and malaria (10.7%) were most prevalent. With the exception of four (0.6%), all other VL patients (509) responded readily to sodium stibogluconate. The factors initiating the outbreak are discussed. Malnutrition and nomadic movements to potential VL endemic areas appeared to be the most important. HIV infection as a possible predisposition seemed remote considering the clinical and epidemiological similarity to VL occurring in East Africa, adequate humoral response in DAT, and immediate positive response to specific anti-Leishmania chemotherapy
Spectra of Homologous Series of Monosubstituted Amides
Infrared spectra of the pure liquid and of dilute solution were observed for Nâmethyl, Nâethyl, Nâpropyl, and Nâbutyl acetamides and propionamides and of Nâdeuterated Nâbutylacetamide. Also infrared spectra of N15âbutylacetamide and Nâdeuterated N15âbutylacetamide and the Raman spectra of Nâbutylacetamide and Nâdeuterated Nâbutylacetamide were observed. In each series a band in the higher members was related to each band of the Nâmethyl compound on the basis of similarity in frequency, intensity, band width, and the influence of dilution. In Nâmethylacetamide and Nâbutylacetamide bands thus related were found to have also similar Raman activities and similar shifts on replacing the peptide hydrogen by deuterium. The extra bands could be related systematically to the extra CH2 groups. The implications of these results in protein spectroscopy and in the spectroscopic study of homologous series is discussed.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/70627/2/JCPSA6-29-5-1097-1.pd
Sicherheitsbeurteilung von Tragwerken mit Fuzzy-Modellen
Die Sicherheit von Tragwerken hĂ€ngt von der zuverlĂ€ssigen Modellierung sĂ€mtlicher Tragwerksparameter ab. Ăblicherweise werden diese Parameter als deterministische oder stochastische GröĂen beschrieben. Stochastische GröĂen sind ZufallsgröĂen, die unscharfe Informationen ĂŒber Tragwerksparameter mit Hilfe von Dichtefunktionen erfassen. Nicht alle unscharfen Tragwerksparameter lassen sich als ZufallsgröĂen darstellen. Sie können jedoch als Fuzzy-GröĂen modelliert werden. Fuzzy-GröĂen beschreiben unscharfe Tragwerksparameter als unscharfe Menge mit Bewertungsfunktion (Zugehörigkeitsfunktion). Die Fuzzy-Modellierung im Bauingenieurwesen umfaĂt die Fuzzifizierung, die Fuzzy-Analyse, die Defuzzifizierung und die Sicherheitsbeurteilung. Sie erlaubt es, Tragwerke mit nicht-stochastischen unscharfen Eingangsinformationen zu untersuchen. Nicht-stochastische Eingangsinformationen treten sowohl bei bestehenden als auch bei neuen Tragwerken auf. Die unscharfen Ergebnisse der Fuzzy-Modellierung gestatten es, das Systemverhalten zutreffender zu beurteilen; sie sind die Ausgangspunkte fĂŒr eine neue Sicherheitsbeurteilung auf der Grundlage der Möglichkeitstheorie. Bei der Fuzzy-Analyse ist die alpha-Diskretisierung vorteilhaft einsetzbar. Bei fehlender Monotonie der deterministischen Berechnungen und unter BerĂŒcksichtigung der NichtlinearitĂ€t wird die Fuzzy-Analyse mit Optimierungsalgorithmen durchgefĂŒhrt. Zwei Beispiele werden diskutiert: die Lösung eines transzendenten Eigenwertproblems und eines linearen Gleichungssystems. Die Systemantworten der Fuzzy-Analyse werden der Sicherheitsbeurteilung zugrunde gelegt. FĂŒr ausgewĂ€hlte physikalische GröĂen werden Versagensfunktionen definiert. Diese bewerten die Möglichkeit des Versagens. Mit Hilfe von Min-max-Operationen der Fuzzy-Set-Theorie erhĂ€lt man aus Versagensfunktion und Fuzzy-Antwort die Versagensmöglichkeit bzw. die Ăberlebensmöglichkeit. Die ermittelte Versagensmöglichkeit reprĂ€sentiert die subjektive Beurteilung der Möglichkeit, daĂ das Ereignis &qout;Versagen&qout; eintritt. Beispiele zeigen die Unterschiede zwischen der Sicherheitsbeurteilung mittels Fuzzy-Modells und mittels deterministischen Modells
Computing Aggregate Properties of Preimages for 2D Cellular Automata
Computing properties of the set of precursors of a given configuration is a
common problem underlying many important questions about cellular automata.
Unfortunately, such computations quickly become intractable in dimension
greater than one. This paper presents an algorithm --- incremental aggregation
--- that can compute aggregate properties of the set of precursors
exponentially faster than na{\"i}ve approaches. The incremental aggregation
algorithm is demonstrated on two problems from the two-dimensional binary Game
of Life cellular automaton: precursor count distributions and higher-order mean
field theory coefficients. In both cases, incremental aggregation allows us to
obtain new results that were previously beyond reach
Big data and diabetes: the applications of big data for diabetes care now and in the future
Aims: Review the current applications of Big Data in diabetes care and consider the future potential.
Methods: Scoping study of the academic literature on Big Data and diabetes care.
Results: Healthcare data are being produced at ever-increasing rates, and this information has the potential to transform the provision of diabetes care. Big Data is beginning to have an impact on diabetes care through data research. The use of Big Data for routine clinical care is still a future application.
Conclusions: Vast amounts of healthcare data are already being produced, and the key is harnessing these to produce actionable insights. Considerable development work is required to achieve these goals
Stress anisotropy in polymer brushes and its effects on wetting
Polymer brushes, coatings consisting of densely grafted macromolecules, have
been known to experience an intrinsic lateral compressive stress, originating
from chain elasticity and excluded volume interactions. This lateral stress
complicates a proper definition of the interface and, thereby, of the
interfacial tension. Moreover, its effect on wettability has remained unclear.
Here, we study the link between grafting-induced compressive lateral stress in
polymer brushes, interfacial tension, and brush wettability using
coarse-grained molecular dynamics simulations. A central result is that the
liquid contact angle is independent of grafting density, which implies that the
strength of the compressive stress inside brush has no influence on the
wettability. Interestingly, though the interfacial tensions lack a proper
definition, the difference in interfacial tension between wet and dry brushes
is perfectly well-defined. We confirm explicitly from Young's law that this
difference offers an accurate description of the brush wettability. It is
demonstrated how these results can be explained from the fact that the
compressive stress appears "symmetrically" in wet and dry brushes. We discuss
our findings in the light of autophobic dewetting and point out the connection
to the Shuttleworth effect for wetting on elastomers
DIRECT METAL LASER SINTERING, USING CONFORMAL COOLING, FOR HIGH VOLUME PRODUCTION TOOLING#
Published ArticleExisting techniques to manufacture conventional tool steel inserts for the plastic injection moulding process are expensive and time-consuming. Complex mould inserts, difficult to manufacture with conventional processes, can be produced using Direct Metal Laser Sintering (DMLS) with Maraging tool steel (MS1). MS1 is an additive manufacturing (AM) material made available by Electro Optical Systems (EOS) GmbH. Contrary to material removal processes, DMLS can produce MS1 tool steel inserts directly from Computer-Aided Design (CAD) files suitable for high volume plastic injection moulding. Through DMLS it is possible to create conformal cooling channels inside the MS1 inserts that have advantages in reducing heat rapidly and evenly. This can result in a reduction of cycle times, cost per product as well as improving part quality by eliminating defects such as warpage and heat sinks.
This paper will present a comparison between Finite Element Analysis (FEA) simulations of the injection mould inserts with actual mould trails of AM and conventional manufactured inserts. It also includes the design and manufacturing of conventional and DMLS inserts and compares the manufacturing costs and lead times. Using FEA simulations, the design of conformal cooling channels is optimised by comparing the mould temperature of different cooling channel layouts.
Bestaande tegnieke vir die vervaardiging van matryse vir die plastiek-inspuit giet tegniek is duur en tyd rowend. Verder is dit nie altyd moontlik om konvensionele metodes vir die vervaardiging van matryse vir geomteries komplekse gietstukke te gebruik nie. Vir sodanige gietsukke kan invoegsels relatief vinnig vervaardig word, deur van direkte laser metal sinterings metodes (DLMS) met Maraging-staal (MS1) gebruik te maak. MS1 is ân laag vervaardings materiaal wat onlangs deur Electro Optical Systems (EOS) GmbH beskikbaar gestel is. Dit is ân pre-allooi, ultra hoĂ« sterkte metaal met goeie meganiese eienskappe. In teenstelling met materiaal verwyderings prosesse (masjienerings prosesse), kan DMLS MS1 staal matryse of insetsels wat vir hoĂ« volume produksie van plastiek gietsukke bruikbaar is, direk vanaf rekenaar-gesteunde ontwerp prosesse vervaardig word. Die gebruik van DMLS kan ook vir die ontwerp en vervaardiging van vorm getroue verkoelings kanale in matryse voorsiening maak, wat tot laer hitte asook die vinnige en eweredige verspreiding daarvan sal lei. Voorgenoemde behoort tot ân aansienlike verlaging in produksie siklus tye te lei met ân dien ooreenkomstige verlaging in die produksie koste asook ân verbetering in die kwaliteit van die vervaardigde produkte a.g.v. die voorkoming van defekte soos kromtrekking en hitte-putte wat normaalweg deur oneweredige hitte verspreiding veroorsaak word
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