Search results for " determination"
showing 10 items of 538 documents
Fallzahlplanung in referenzkontrollierten Diagnosestudien
2002
Purpose: A tutorial illustration of a flexible approach to determine the sample size in reference-controlled diagnostic trials. Materials and Methods: Assuming the usual setting of a new diagnostic method to be compared with a reference method, the emphasis is on the sensitivity of the new method in comparison with the reference method, using a binary outcome (positive versus negative) for both methods. Based on the confidence interval of the sensitivity, a simple but flexible procedure for determining the sample size is described, which incorporates clinically interpretable information. The procedure is illustrated by the fictious planning of a trial to assess the diagnostic value of MRI v…
Effect of rapid maxillary expansion on sleep apnea-hypopnea syndrome in growing patients. A meta-analysis.
2019
Background Changes produced in the upper airway after rapid maxillary expansion makes this procedure a therapeutic option for treating sleep apnea-hypopnea syndrome (SAHS) in children. The objective of this systematic review and meta-analysis was to analyze the evidence available for the effects of rapid maxillary expansion (RME) on SAHS, analyzing changes produced in oximetric variables: apnea-hypopnea index (AHI); oxygen saturation (SO2); sleep efficiency (SE), total sleep time (TST), percentage of rapid eye movement (REM) phase; and arousal index (AI). Material and Methods An electronic search was conducted in the PubMed, Scopus, Embase, and Cochrane databases, and in grey literature (Op…
Variability of near-surface saturated hydraulic conductivity for the clay soils of a small Sicilian basin
2019
Abstract Proper characterization of saturated hydraulic conductivity, Ks, of clay soils in a hillslope or a basin is still a challenge for soil science. In this investigation, the clay soils of the Maganoce (Sicily, Italy) basin were sampled at 19 sampling sites by the BEST procedure of soil hydraulic characterization. More OM implied less compact conditions (decreasing dry soil bulk density; coefficient of determination, R2 = 0.67), more stability to water of the soil aggregates (increasing water stable aggregates; R2 = 0.83) and, consequently, higher Ks values (R2 = 0.54). Variability of Ks was lower in the steeper zones of the basin than in the flatter ones. A comparison with the Ks data…
Current Bioactive Azole-Containing Natural Products
2010
ARYL-VINYLSULFONE—REAGENTIEN ZUM SCHUTZ UND NACHWEIS VON THIOLFUNKTIONEN
1983
Abstract Aryl vinyl sulfones selectively react with thiol groups to acid-stable compounds which easily are cleaved by mild bases to thiol compounds. Ester and amide groups are not attacked under these conditions. Therefore, these compounds are good protecting groups or labels in peptide chemistry. The following aryl vinyl sulfones were investigated: phenyl vinyl sulfone 1, p-carbethoxyphenyl vinyl sulfone 15 and the fluorescent 5-dimethylaminonaphthyl 1-vinyl sulfone 5 and 5-methoxynaphthyl-1 vinyl sulfone 10. The last two compounds are very useful reagents for the quantitative determination of SH-groups in polypeptides such as enzymes. Aryl-vinylsulfone reagieren selektiv mit Thiolgruppen …
Evidence of the Gluten-Free and Casein-Free Diet in Autism Spectrum Disorders
2014
In autism spectrum disorders, many parents resort to alternative treatments and these are generally perceived as risk free. Among these, the most commonly used is the gluten-free, casein-free diet. The objective of this work was to conduct a systematic review of studies published from 1970 to date related to the gluten-free, casein-free diet in autism spectrum disorder patients. Few studies can be regarded as providing sound scientific evidence since they were blinded randomized controlled trials, and even these were based on small sample sizes, reducing their validity. We observed that the evidence on this topic is currently limited and weak. We recommend that it should be only used after…
Bestimmung von Tri-n-butylphosphat in Plasmapräparaten nach Festphasenextraktion und Kapillar-Gaschromatographie
1988
A simple method for the quantitative determination of tri-n-butylphosphate in blood plasma preparations is described. The sample is passed through an octadecyl extraction column from which tri-n-butylphosphate is eluted with chloroform. By capillary GC 50 micrograms/l tri-n-butylphosphate can be detected with a recovery of more than 90%.
Über die struktur eines räumlich gebauten, aus 2.4.6-Tri(hydroxymethyl)-phenol erhaltenen polykondensates
1960
Bei der Schmelzkondensation von 2.4.6-Tri(hydroxymethyl)-phenol entsteht ein raumlich gebautes Polykondensat, das uber Dimethylenatherbrucken verknupfte Phenolkerne enthalt. Dies kann durch die quantitative Bestimmung der bei der Polykondensation erhaltenen Abspaltungsprodukte gezeigt werden; ferner durch die Bromanalyse der Hydrolyseprodukte aus der quantitativ verfolgten Hydrolyse der Polykondensate mit gasformigem HBr. Setzt man die ublichen Atomabstande und Bindungswinkel in Rechung, so sollten in dem raumlich gebauten Netzwerk Dreikern-, Vierkern-, Funfkern-, Sechskern- und hohere Kernringe vorkommen konnen. Ein Beispiel hierfur ist die Vierkernringverbindung mit der Konstitution IIIβ.…
Triclinic conformational polymorph of N,N,N′,N′-tetrakis(2-cyanoethyl)-1,2-ethylenediamine (TCED)
2018
Abstract The crystal and molecular structures of two polymorphs of N,N,N′,N′-tetrakis(2-cyanoethyl)-1,2-ethylenediamine have been characterized by X-ray diffraction along with density functional theory (DFT) studies. The molecules differ from each other by conformation. N,N,N′,N′-tetrakis(2-cyanoethyl)-1,2-ethylenediamine has been synthesized by cyanoethylation of ethylenediamine. Cyanoethylation of vicinal diamines is important for the synthesis of hyperbranched polymeric materials applied as catalysts, surfactants and encapsulating agents in drug delivery systems. The molecular geometry of N,N,N′,N′-tetracyanoethyl-1,2-ethylenediamine is similar to that of homologous compounds. DFT calcul…