Search results for "position"
showing 10 items of 6771 documents
Conductive Directly Fused Poly(Porphyrin) Coatings by Oxidative Chemical Vapour Deposition - From Single- to Triple-Fused
2019
Addition of organolithium reagents to cinnamic acids
1999
Abstract Reaction of tert -butyllithium with p - and m -substituted cinnamic acids at low temperature affords mixtures of 1,4- and 1,3-addition products, whose composition depend on the nature of the substituents. Electron-donating and electron-withdrawing groups favour 1,4- and 1,3-additions, respectively. Linear correlations are obtained with electronic effect and with radical substituent constants.
ChemInform Abstract: Facile Synthesis of Pyrazoles and Pyrroles via Thermolysis of Tetrazolo[1,5-b]pyridazines, Tetrazolo[1,5-a]pyrimidines and Tetra…
2010
Abstract A simple and high yielding preparation of pyrazoles and pyrroles is described. Thermolysis of tetrazolo[1,5- b ]pyridazines, tetrazolo[1,5- a ]pyrimidines and tetrazolo[1,5- a ]pyridines allowed easy ring contraction thus providing a facile preparation of cyanopyrazole and cyanopyrrole heterocycles. Since the cyano group is a versatile precursor of other functionalities, the reaction appears of particular interest for the construction of a variety of pyrazoles and pyrroles. The simple preparation of the starting tetrazole derivatives, the relatively mild conditions employed, and the very short reaction times make this versatile procedure of great synthetic utility and applicable bo…
Volatile Constituents ofTeucrium poliumL. from Turkey
1998
Abstract The volatile constituents obtained from the aerial parts of Teucrium polium were analyzed by GC and GC/MS. The oil was found to contain 37 components, of which 30 were identified. The major constituents were β-pinene (18.0%), β-caryophyllene (17.8%), α-pinene (12.0%), caryophyllene oxide (10.0%), myrcene (6.8%) and germacrene-D (5.3%)
Associations of age, body size, and maturation with physical activity intensity in different laboratory tasks in children
2021
We investigated the associations of age, sex, body size, body composition, and maturity with measures of physical activity (PA) intensity in children. PA intensity was assessed using VO2 as % of VO2reserve or VO2 at ventilatory threshold (VT), muscle activity measured by textile electromyography, mean amplitude deviation (MAD) measured by accelerometry, and metabolic equivalent of task (MET) during laboratory activities.Age, stature, and muscle mass were inversely associated with VO2 as % of VO2reserve and % of VT, during walking or running on a treadmill for 4, 6, and 8 km/h (Spearman r = -0.645 to -0.358). Age was inversely associated with MAD during walking on treadmill for 4 km/h (r = -…
Reflexivity and therapeutic change in the cognitive-constructive psychotherapy of panic disorder
2000
Mandrel-less fabrication of biomimetic electrospun microfiber wires for tissue engineering applications
2021
This study introduces a novel mandrel-less electrodeposition method and a novel electrode prototypes useful for tissue engineering applications. More specifically, in this study a novel fabrication protocol to electrospun fibers-based chords, with length spanning from 2 cm to virtually no limitations on longitudinal length, is presented. For the first part of this study, Poly(ester urethane) urea (PEUU) was used to fabricate, by electrodeposition technique, continuous microfiber wires with controlled micro-architecture and tunable mechanics. A novel apparatus to process degradable or non-degradable polymers was used. Soft tissue injuries are common in daily clinical and surgical practice. O…
Behavior of Calcium Phosphate–Chitosan–Collagen Composite Coating on AISI 304 for Orthopedic Applications
2022
Calcium phosphate/chitosan/collagen composite coating on AISI 304 stainless steel was investigated. Coatings were realized by galvanic coupling that occurs without an external power supply because it begins with the coupling between two metals with different standard electrochemical potentials. The process consists of the co-deposition of the three components with the calcium phosphate crystals incorporated into the polymeric composite of chitosan and collagen. Physical-chemical characterizations of the samples were executed to evaluate morphology and chemical composition. Morphological analyses have shown that the surface of the stainless steel is covered by the deposit, which has a very r…
Can Physiological and Psychological Factors Predict Dropout from Intense 10-Day Winter Military Survival Training?
2020
Background: In the military context, high levels of physiological and psychological stress together can compromise individual&rsquo
Līdzdalības didaktiskās stratēģijas kā dažādības pedagoģiskais risinājums vidusskolēniem STEM kompetenču iegūšanas procesā
2017
Mūsdienu pasaulē, kur tehnoloģijas nemitīgi turpina attīstīties, skolotājiem ir nepieciešams pielietot šo iespaidīgo rīku, lai rosinātu ieinteresētību skolēnos un motivētu viņus. Viens no Meksikas Vidējās izglītības sistēmas reformas mērķiem ir attīstīt vispārējas un disciplināras kompetences Fizika IV priekšmetā starp dažādiem vidusskolas skolēniem. Lai sasniegtu šo mērķi, tiek izmantotas tādas didaktiskās stratēģijas kā prezentācijas klasē un savstarpēja sadarbība starp skolēniem, kas tiek papildinātas ar Robert Marzano Dimensiju teoriju, konstruktīvisma fokusu un padziļinātu mācību apguvi. Pielietojot šīs stratēģijas, tiek demonstrēts, ka motivēti skolēni strādā labāk, apgūst kompetences…