498 research outputs found
Yoga \u27Holistic\u27 Exercise in Ohio
Yoga is depicted in U.S. popular culture as the sacred practice of an ancient tradition, guaranteed to initiate the western participant into the secrets of health and well being, i.e. a low-impact exercise regimen. However, the yoga that is practiced in the U.S. is often removed from its actual history. The physical practices are regularly isolated from the holistic philosophy and come to be understood as the entirety of yoga and marketed as a spiritual form of exercise. This paper will explore literature relevant to these themes and examine the reasons for yoga\u27s popularity and the manner in which it is incorporated into the lives of those who practice it
Identification and quantification of cannabinol as a biomarker for local hemp retting in an ancient sedimentary record by HPTLC-ESI-MS
Cannabis products have been used in various fields of everyday life for many centuries, and applications in folk medicine and textile production have been well-known for many centuries. For traditional textile production, hemp fibers were extracted from the stems by water retting in stagnant or slow-moving waters. During this procedure, parts of the plant material‚ among them phytocannabinoids‚ are released into the water. Cannabinol (CBN) is an important degradation product of the predominant phytocannabinoids found in Cannabis species. Thus, it is an excellent indicator for present as well as ancient hemp water retting. In this study, we developed and validated a simple and fast method for the determination of CBN in sediment samples using high-performance thin-layer chromatography (HPTLC) combined with electrospray ionization mass spectrometry (ESI-MS), thereby testing different extraction and cleanup procedures‚ as well as various sorbents and solvents for planar chromatography. This method shows a satisfactory overall analytical performance with an average recovery rate of 73%. Our protocol enabled qualitative and quantitative analyses of CBN in samples of a bottom sediment core‚ having been obtained from a small lake in Northern India, where intense local retting of hemp was suggested in the past. The analyses showed a maximum CBN content in pollen zone 4 covering a depth range of 262–209 cm, dating from approximately 480 BCE to 1050 CE. These findings correlate with existing records of Cannabis-type pollen. Thus, the method we propose is a helpful tool to track ancient hemp retting activities
Ein pädagogischer Synergieeffekt für Praxis und Theorie: Themenzentrierte Medienarbeit
Rezension zu: Keilhauer, Jan, und Bernd Schorb, Hrsg. 2010. Themenzentrierte Medienarbeit mit Jugendlichen: ein Modellprojekt mit deutschen und tschechischen Jugendlichen zum Thema Präimplantationsdiagnostik. München: Kopaed
Valence Virtual Orbitals: An unambiguous ab initio quantification of the LUMO concept
Many chemical concepts hinge on the notion of an orbital called the lowest unoccupied molecular orbital, or LUMO. This hypothetical orbital and the much more concrete highest occupied molecular orbital (HOMO) constitute the two “frontier orbitals”, which rationalize a great deal of chemistry. A viable LUMO candidate should have a sensible energy value, a realistic shape with amplitude on those atoms where electron attachment or reduction or excitation processes occur, and often an antibonding correspondence to one of the highest occupied MOs. Unfortunately, today’s quantum chemistry calculations do not yield useful empty orbitals. Instead, the empty canonical orbitals form a large sea of orbitals, where the interesting valence antibonds are scrambled with the basis set’s polarization and diffuse augmentations. The LUMO is thus lost within a continuum associated with a detached electron, as well as many Rydberg excited states. A suitable alternative to the canonical orbitals is proposed, namely, the valence virtual orbitals. VVOs are found by a simple algorithm based on singular value decomposition, which allows for the extraction of all valence-like orbitals from the large empty canonical orbital space. VVOs are found to be nearly independent of the working basis set. The utility of VVOs is demonstrated for construction of qualitative MO diagrams, for prediction of valence excited states, and as starting orbitals for more sophisticated calculations. This suggests that VVOs are a suitable realization of the LUMO, LUMO + 1, ... concept. VVO generation requires no expert knowledge, as the number of VVOs sought is found by counting s-block atoms as having only a valence s orbital, transition metals as having valence s and d, and main group atoms as being valence s and p elements. Closed shell, open shell, or multireference wave functions and elements up to xenon may be used in the present program
Bis(NHC)-Pincerliganden und deren Metallkomplexe
Die vorliegende Arbeit beschäftigt sich mit dem Bis(NHC)-Pincerliganden Bimca (3,6-Di-tert-butyl-1,8-bis(imidazolin-2-yliden)-9H-carbazolid). Es wird eine optimierte Syntheseroute zur Darstellung des Grundgerüsts 3 entwickelt und davon ausgehend wird eine Derivatisierung des Bimca-Liganden zu verschiedenen Ligandklassen beschrieben. In einem Teil der Arbeit konnte das Bimca-Grundgerüst 3 in ein macrocyclisches System überführt werden. Es wurden die Ligandvorstufen H2(bimcacyPy)·2HX (4) und H(bimcacyMPy)·2HI (6) synthetisiert. Die Darstellung von Metallkomplexen mit dem Pyrrol-verknüpften Bimcaliganden H2(bimcacyPy)·2HX (4) erweist sich als nicht trivial, da sich das Ligandsystem unter basischen Bedingungen leicht zersetzt. Durch die Einführung einer Methylschutzgruppe am Pyrrol-Stickstoffatom, wie in dem Ligandsystem H(bimcacyMPy)·2HI (6), konnte die Zersetzung verhindert und im Anschluss die Darstellung des Rhodium- 6-2 und Iridiumkomplexes 6-3 durchgeführt werden. Durch die Einführung von Hydroxyethyl- beziehungsweise Bromoethylketten konnten die zwei Ligandsysteme H(bimcaEtOH)·2HBr (7) und H(bimcaEtBr)·2HBr (8) synthetisiert werden. Bei der Darstellung der zugehörigen Metallkomplexe konnte gezeigt werden, dass diese sich durch Reaktionen, wie beispielsweise eine Eliminierungsreaktion, weiter funktionalisieren lassen. Bei der dritten synthetisierten Ligandklasse handelt es sich um doppelte Pincerliganden. Durch die Reaktion von zwei Grundeinheiten 3 mit 1,2 Dibromethan konnte gezeigt werden, dass das Carbazolgrundgerüst je nach eingesetztem Verhältnis von 1,2 Dibromethan zu einem doppelten Pincerliganden, mit einer oder zwei verknüpfenden Ethylketten umgesetzt werden kann ((11) und (10)). Das Ligandsystem (10) eignet sich gut zur Darstellung von dinuclearen Metallkomplexen, wobei in Lösung zwei Spezies beobachtet werden können, welche mit großer Wahrscheinlichkeit von einem in Lösung vorliegenden Gleichgewicht zwischen einer anti- und einer syn-verknüpften Spezies stammen
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