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971.
Background
Increased Al concentration causes reduction of mitotic activity, induction of nucleolar alteration, increase of the production of ROS and alteration of several antioxidant enzyme activities in plant cells. Allium cepa is an excellent plant and a useful biomarker for environmental monitoring. Limited information is available about the effects of Al on nucleoli, antioxidant enzyme system, contents of MDA and soluble protein in A. cepa. Therefore, we carried out the investigation in order to better understand the effects of Al on the growth, nucleoli in root tip cells and selected physiological and biochemical characters. 相似文献972.
Ricardo Ribeiro Silva Carlos Renato Corso Dácio Roberto Matheus 《World journal of microbiology & biotechnology》2010,26(5):841-846
Estimating fungal growth is important in processes of soil bioremediation. It has been demonstrated that ergosterol is a good
indicator of fungal biomass in solid substrata. In the present study were evaluated the effects upon the ergosterol rate of
Lentinus crinitus Berk. and Psilocybe castanella Peck through the culture conditions of these fungi, which are evaluated for the bioremediation of soils contaminated by organochlorates.
A good correlation between fungal biomass and ergosterol was observed for both species. The culture conditions did not influence
the ergosterol rate of L. crinitus. Yet the ergosterol rate of P. castanella was influenced from 35 days of culture and when grown in the presence of 15.00 g hexachlorobenzene l−1 of culture medium. So it is possible to estimate growth of both species using ergosterol as indicator in processes of soil
bioremediation since the influences observed in the ergosterol rate of P. castanella are considered. 相似文献
973.
Estimating stand volume in broad-leaved forest using discrete-return LiDAR: plot-based approach 总被引:1,自引:0,他引:1
Keiko Ioki Junichi Imanishi Takeshi Sasaki Yukihiro Morimoto Katsunori Kitada 《Landscape and Ecological Engineering》2010,6(1):29-36
Quantitative assessment of forests is important at a variety of scales for forest planning and management. This study investigated
the use of small-footprint discrete-return lidar for estimating stand volume in broad-leaved forest at plot level. Field measurements
were conducted at 20 sample plots in the study area in western Japan, composed of temperate broad-leaved trees. Five height
variables and two density variables were derived from the lidar data: 25th, 50th, 75th, and 100th percentiles, and mean of
laser canopy heights as height variables (h
25, h
50, h
75, h
100, h
mean); and ground fraction and only-and-vegetation fraction (d
GF, d
OVF) as density variables, defined respectively as the proportion of laser returns that reached the ground, and the proportion
of only echoes (i.e., single pulse returns for which the first and last pulses returned from the same point) within vegetation
points. In addition, the normalized difference vegetation index (NDVI), which is often used as an estimator for leaf area
index (LAI) and above-ground biomass, was derived from multispectral digital imagery as an alternative density variable (d
NDVI). Nonlinear least-square regression with cross-validation analysis was performed with single variables and combinations;
a total of 23 models were studied. The best prediction was found when h
75 and d
OVF were used as independent variables, resulting in adjusted R
2 of 0.755 and root-mean-square error (RMSE) of 41.90 m3 ha−1, corresponding to 16.4% of the mean stand volume, better than or comparable to the prediction models of previous studies. 相似文献
974.
Shari L. Laprise 《Molecular biotechnology》2010,45(2):187-197
The “holy grail” of regenerative medicine is the identification of an undifferentiated progenitor cell that is pluripotent,
patient specific, and ethically unambiguous. Such a progenitor cell must also be able to differentiate into functional, transplantable
tissue, while avoiding the risks of immune rejection. With reports detailing aberrant genomic imprinting associated with assisted
reproductive technologies (ART) and reproductive cloning, the idea that human embryonic stem cells (hESCs) derived from surplus
in vitro fertilized embryos or nuclear transfer ESCs (ntESCs) harvested from cloned embryos may harbor dangerous epigenetic
errors has gained attention. Various progenitor cell sources have been proposed for human therapy, from hESCs to ntESCs, and
from adult stem cells to induced pluripotent stem cells (iPS and piPS cells). This review highlights the advantages and disadvantages
of each of these technologies, with particular emphasis on epigenetic stability. 相似文献
975.
There is a special emphasis today on integrating traditional healing within health services. However, most areas in which
there is a system of traditional healing have undergone colonization and a number of pressures suppressing tradition for hundreds
of years. The question arises as to how one can understand today’s tradition in light of earlier traditions. This article
is based on material collected in Sámi areas of Finnmark and Nord-Troms Norway; it compares local healing traditions with
what is known of earlier shamanic traditions in the area. The study is based on 27 interviews among healers and their patients.
The findings suggest that although local healing traditions among the Sámi in northern Norway have undergone major transformations
during the last several hundred years, they may be considered an extension of a long-standing tradition with deep roots in
the region. Of special interest are also the new forms tradition may take in today’s changing global society. 相似文献
976.
K Königsson K Törneke IV Engeland K Odensvik H Kindahl 《Acta veterinaria Scandinavica》2003,44(4):153
The pharmacokinetics and the prostaglandin (PG) synthesis inhibiting effect of flunixin were determined in 6 Norwegian dairy
goats. The dose was 2.2 mg/kg body weight administered by intravenous (i.v.), intramuscular (i.m.) and oral (p.o.) routes
using a cross-over design. Plasma flunixin content was analysed by use of liquid chromatography and the PG synthesis was evaluated
by measuring plasma 15-ketodihydro-PGF2α by a radioimmuno-assay. Results are presented as median (range). The elimination half-lives (t1/2·λ) were 3.6 (2.0–5.0), 3.4 (2.6–6.8) and 4.3 (3.4–6.1) h for i.v., i.m. and p.o. administration, respectively. Volume of distribution
at steady state (Vdss) was 0.35 (0.23–0.41) L/kg and clearance (CL), 110 (60–160) mL/h/kg. The plasma concentrations after oral administration
showed a double-peak phenomenon with the two peaks occurring at 0.37 (0.25–1) and 3.5 (2.5–5.0) h, respectively. Both peaks
were in the same order of magnitude. Bioavailability was 79 (53–112) and 58 (35%–120)% for i.m. and p.o. administration, respectively.
15-Ketodihydro-PGF2α plasma concentrations decreased after flunixin administration independent of the route of administration. 相似文献
977.
Subspecific relationships of the European beaverCastor fiber have been obscured by failure to follow the rules of the International Code of Zoological Nomenclature and remain an open
issue. Inconsequence in the use of subspecies names caused a nomenclatural as well as a taxonomic confusion. We discuss these
controversial and incorrect nomenclatural decisions, and recognize 9 nominal subspecies of European beaver, bearing 9 available
names:C. f. fiber Linnaeus, 1758,C. f. galliae Geoffroy, 1803, C. f. albicus Matschie, 1907,C. f. vistulanus Matschie, 1907,C. f. pohlei Serebrennikov, 1929,C. f. birulai Serebrennikov, 1929,C. f. tuvinicus Lavrov, 1969,C. f. belorussicus Lavrov, 1981, andC. f. orientoeuropaeus Lavrov, 1981. 相似文献
978.
979.
Lysek N Kinscherf R Claus R Lindel T 《Zeitschrift für Naturforschung. C, Journal of biosciences》2003,58(7-8):568-572
The intertidal sponge Hymeniacidon heliophila which survives under intense sunlight contains the antioxidant amino acid L-5-hydroxytryptophan (L-5-HTP) as major constituent. The content of L-5-HTP was determined as (0.45 +/- 0.23)% of the dry weight by quantitative NMR-spectroscopical analysis with an internal standard. Other known antioxidants such as flavonoids, carotenoids or tocopherol derivatives were absent. Both the oxidation potential and the concentration of L-5-HTP in H. heliophila correspond to the values observed for flavonoids being major antioxidants in plants. It was shown that L-5-HTP suppresses UV-induced apoptosis in human monocytes at the same concentrations as it occurs in the sponge tissue. 相似文献
980.
Soil carbon saturation: concept,evidence and evaluation 总被引:20,自引:0,他引:20
Catherine E. Stewart Keith Paustian Richard T. Conant Alain F. Plante Johan Six 《Biogeochemistry》2007,86(1):19-31
Current estimates of soil C storage potential are based on models or factors that assume linearity between C input levels
and C stocks at steady-state, implying that SOC stocks could increase without limit as C input levels increase. However, some
soils show little or no increase in steady-state SOC stock with increasing C input levels suggesting that SOC can become saturated with respect to C input. We used long-term field experiment data to assess alternative hypotheses of soil carbon storage
by three simple models: a linear model (no saturation), a one-pool whole-soil C saturation model, and a two-pool mixed model
with C saturation of a single C pool, but not the whole soil. The one-pool C saturation model best fit the combined data from
14 sites, four individual sites were best-fit with the linear model, and no sites were best fit by the mixed model. These
results indicate that existing agricultural field experiments generally have too small a range in C input levels to show saturation
behavior, and verify the accepted linear relationship between soil C and C input used to model SOM dynamics. However, all
sites combined and the site with the widest range in C input levels were best fit with the C-saturation model. Nevertheless,
the same site produced distinct effective stabilization capacity curves rather than an absolute C saturation level. We conclude
that the saturation of soil C does occur and therefore the greatest efficiency in soil C sequestration will be in soils further
from C saturation.
相似文献
Catherine E. StewartEmail: |