Some relations between the structure and the antibacterial activity of natural coumarins

Zusammenfassung Von 15 untersuchten natürlichen Cumarinen und Furocumarinen besitzen Ammoresinol und Ostruthin stärkste Wirkung auf Gram-positive Mikroorganismen. Zur Ammoresinolwirkung ist die Erhaltung der freien -OH-Gruppen notwendig, während bei Ostruthin durch Vitamin K₂ die Wirksamkeit vermindert wird.     

Hypolipidemic action of onion and garlic unsaturated oils in sucrose fed rats over a two-month period

Summary The feeding of a high-sucrose diet to normal rats for a period of 2 months increased serum and tissue cholesterol and triglycerides very significantly. Simultaneous feeding of the unsaturated oils of onion or garlic with the sucrose diet counterated these effects of sucrose. However, along with the lipid-reducing effects, a small but significant tissue-protein reducing effect of the oils were also observed. The hypolipidemic action of the oils may be related to their action on both lipid and protein synthesis.The authors acknowledge with thanks Prof. J. K. Sen Gupta, and the authorities of the University of Maiduguri for the award of a grant to this project. Authors, to whom reprint requests should be addressed.     

Selective population inversion in NMR

Population inversion of a selected region of a spectrum is a concept which has wide application in both NMR spectroscopy and imaging. While inversion of population at any one frequency is a trivial matter, ensuring an accurate inversion over a specified bandwidth, with negligible perturbation of the magnetization outside that bandwidth, is a major problem. However, by using as a driving function a complex radiofrequency (r.f.) pulse with an envelope of the form (sech beta t)1+5i where 1/beta is the temporal width and t is time, we have found that above a critical r.f. power threshold, magnetization is accurately inverted over a very sharply defined bandwidth, while outside that region, magnetization is returned to its initial position, and population is unaffected. Within the broad limits imposed by our equipment, we have also discovered that the phenomenon is independent of the incident r.f. power.     

Late Cenozoic high-resolution magnetostratigraphy in the Kunlun Pass Basin and its implications for the uplift of the northern Tibetan Plateau

The Kunlun Pass Basin, located in the middle of the eastern Kunlun Mountains, received relatively continuous late Cenozoic sediments from the surrounding mountains, archiving great information to understand the deformation and uplift histories of the northern Tibetan Plateau. The Kunlun-Yellow River Movement, identified from the tectonomorphologic and sedimentary evolution of the Kunlun Pass Basin by Cui Zhijiu et al. （1997, 1998）, is roughly coincident with many important global and Plateau climatic and environmental events, becoming a crucial time interval to understand tectonic-climatic interactions. However, the ages used to constrict the events remain great uncertainty. Here, we present the results of detailed magnetostratigraphy of the late Cenozoic sediments in the Kunlun Pass Basin, which show the basin sediments were formed between about 3.6 Ma and 0.5 Ma and the Kunlun-Yellow River Movement occurred at 1.2 to ～0.78 Ma. The lithology, sedimentary facies and lithofacies associations divide the basin into five stages of tectonosedimentary evolution, indicating the northern Tibetan Plateau having experienced five episodes of tectonic uplifts at ～3.6, 2.69-2.58, 1.77, 1.2, 0.87 and ～0.78 Ma since the Pliocene.