331 research outputs found
SALT TOLERANCE OF TURFGRASS Puccinellia dirtans: II. IONIC INTERACTION IN THE ROOTS
In this study, multi-compartment transport boxes were used to determine the mobility of ions in the execised roots. For measuring Na uptake, the concentrations of 1, 50 and 150 mM NaCI were used in the external medium, whilst Ca were 0 and 2. 0 mM. The uptake of K was measured from 1.0 mM KCI in the presence of Na (0.50 and 150 mM) and Ca (0.50 and 2.0 mM). In the present study, 22 Na and 86 Rb were used to label Na and K in the external medium, respectively. Addition of Ca inhibited Na uptake in the roots exposed to 1.0 mM and 50 mM NaCI, thought Ca was relatively less effective in 150 mM. High concentrations of NaCI brought about the reduction of K uptake. Calcium, however, did not show any importance in recovering the uptake of K from the adverse effect of Na when the roots were exposed 10 50 mM NaCI, thought stimulating effect of Ca was observed at 150 mM NaCI. The results revealed that the pattern of ionic interactions in Puccinellia distans differs much with that generally found in most of halophyte plants
Lagrangian description of the fluid flow with vorticity in the relativistic cosmology
We develop the Lagrangian perturbation theory in the general relativistic
cosmology, which enables us to take into account the vortical effect of the
dust matter. Under the Lagrangian representation of the fluid flow, the
propagation equation for the vorticity as well as the density is exactly
solved. Based on this, the coupling between the density and vorticity is
clarified in a non-perturbative way. The relativistic correspondence to the
Lagrangian perturbation theory in the Newtonian cosmology is also emphasized.Comment: 14 pages (RevTeX); accepted for publication in Phys. Rev.
Age of the Universe: Influence of the Inhomogeneities on the global Expansion-Factor
For the first time we calculate quantitatively the influence of
inhomogeneities on the global expansion factor by averaging the Friedmann
equation. In the framework of the relativistic second-order
Zel'dovich-approximation scheme for irrotational dust we use observational
results in form of the normalisation constant fixed by the COBE results and we
check different power spectra, namely for adiabatic CDM, isocurvature CDM, HDM,
WDM, Strings and Textures. We find that the influence of the inhomogeneities on
the global expansion factor is very small. So the error in determining the age
of the universe using the Hubble constant in the usual way is negligible. This
does not imply that the effect is negligible for local astronomical
measurements of the Hubble constant. Locally the determination of the
redshift-distance relation can be strongly influenced by the peculiar velocity
fields due to inhomogeneities. Our calculation does not consider such effects,
but is contrained to comparing globally homogeneous and averaged inhomogeneous
matter distributions. In addition we relate our work to previous treatments.Comment: 10 pages, version accepted by Phys. Rev.
Association of angiopoietin-like protein 3 with hepatic triglyceride lipase and lipoprotein lipase activities in human plasma
éæȹ性ćŠć»ćŠçł»ç 究ç§Background: The relationship between plasma angiopoietin-like protein 3 (ANGPTL3), and lipoprotein lipase (LPL) activity and hepatic triglyceride lipase (HTGL) activity has not been investigated in the metabolism of remnant lipoproteins (RLPs) and high-density lipoprotein (HDL) in human plasma. Methods: ANGPTL3, LPL activity, HTGL activity, RLP-C and RLP-TG and small, dense LDL-cholesterol (sd LDL-C) were measured in 20 overweight and obese subjects in the fasting and postprandial states. Results: Plasma TG, RLP-C, RLP-TG and sd LDL-C were inversely correlated with LPL activity both in the fasting and postprandial states, but not correlated with HTGL activity and ANGPTL3. However, plasma HDL-C was positively correlated with LPL activity both in the fasting and postprandial states, while inversely correlated with HTGL activity. ANGPTL3 was inversely correlated with HTGL activity both in the fasting and postprandial states, but not correlated with LPL activity. Conclusion: HTGL plays a major role in HDL metabolism, but not RLP metabolism. These findings suggest that ANGPTL3 is strongly associated with the inhibition of HTGL activity and regulates HDL metabolism, but not associated with the inhibition of LPL activity for the metabolism of RLPs in human plasma
The development of a knowledge base for basic active structures: an example case of dopamine agonists
<p>Abstract</p> <p>Background</p> <p>Chemical compounds affecting a bioactivity can usually be classified into several groups, each of which shares a characteristic substructure. We call these substructures "basic active structures" or BASs. The extraction of BASs is challenging when the database of compounds contains a variety of skeletons. Data mining technology, associated with the work of chemists, has enabled the systematic elaboration of BASs.</p> <p>Results</p> <p>This paper presents a BAS knowledge base, BASiC, which currently covers 46 activities and is available on the Internet. We use the dopamine agonists D1, D2, and Dauto as examples and illustrate the process of BAS extraction. The resulting BASs were reasonably interpreted after proposing a few template structures.</p> <p>Conclusions</p> <p>The knowledge base is useful for drug design. Proposed BASs and their supporting structures in the knowledge base will facilitate the development of new template structures for other activities, and will be useful in the design of new lead compounds via reasonable interpretations of active structures.</p
The Zel'dovich-type approximation for an inhomogeneous universe in general relativity: second-order solutions
The gravitational instability of inhomogeneities in the expanding universe is
studied by the relativistic second-order approximation. Using the tetrad
formalism we consider irrotational dust universes and get equations very
similar to those given in the Lagrangian perturbation theory in Newtonian
cosmology. Neglecting the cosmological constant and assuming a flat background
model we give the solutions of the nonlinear dynamics of cosmological
perturbations. We present the complete second-order solutions, which extend and
improve earlier works.Comment: 20 pages, LaTeX, no figure
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