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101.
102.
Michal Doua 《Chirality》2019,31(3):202-210
A sensitive chiral high performance liquid chromatography (HPLC) method for the determination of aliphatic primary amino alcohol isomers with o‐phthaldialdehyde/mercaptoethanol precolumn derivatization has been developed and validated. Seven chiral columns were tested in a reversed phase mode. Excellent enantioseparation with the resolution more than 2.0 was achieved on Chiralcel OJ‐3R. The effect of various chromatographic conditions including column temperature, acetonitrile content in the mobile phase, buffer pH, buffer concentration, and buffer type in the mobile phase on the retention and the selectivity was investigated. The final mobile phase consisted of binary mixture of 20mM ammonium formate solution with acetonitrile (75:25; v/v). The analyses were performed at mobile phase flow rate of 1.0 mL/min and the column temperature of 40°C. The fluorescence detection was performed at excitation wavelength of 345 nm and emission wavelength of 450 nm. The developed method was fully validated in terms of linearity, sensitivity, accuracy, precision, intermediate precision, and selectivity according to International Council for Harmonisation of Technical Requirements for Pharmaceuticals for Human Use guidelines using internal normalization procedure. The proposed chiral method was proved to be highly sensitive, simple, and rapid and was successfully applied to the determination of D‐Valinol content in commercially available samples of L‐Valinol. 相似文献
103.
Eoghan A. Aston Gareth J. Williams J. A. Mattias Green Andrew J. Davies Lisa M. Wedding Jamison M. Gove Jean‐Baptiste Jouffray Timothy T. Jones Jeanette Clark 《Ecography》2019,42(3):578-590
Understanding and predicting patterns of spatial organization across ecological communities is central to the field of landscape ecology, and a similar line of inquiry has begun to evolve sub‐tidally among seascape ecologists. Much of our current understanding of the processes driving marine community patterns, particularly in the tropics, has come from small‐scale, spatially‐discrete data that are often not representative of the broader seascape. Here we expand the spatial extent of seascape ecology studies and combine spatially‐expansive in situ digital imagery, oceanographic measurements, spatial statistics, and predictive modeling to test whether predictable patterns emerge between coral reef benthic competitors across scales in response to intra‐island gradients in physical drivers. We do this around the entire circumference of a remote, uninhabited island in the central Pacific (Jarvis Island) that lacks the confounding effects of direct human impacts. We show, for the first time, that competing benthic groups demonstrate predictable scaling patterns of organization, with positive autocorrelation in the cover of each group at scales < ~1 km. Moreover, we show how gradients in subsurface temperature and surface wave power drive spatially‐abrupt transition points in group dominance, explaining 48–84% of the overall variation in benthic cover around the island. Along the western coast, we documented ten times more sub‐surface cooling‐hours than any other part of the coastline, with events typically resulting in a drop of 1–4°C over a period of < 5 h. These high frequency temperature fluctuations are indicative of upwelling induced by internal waves and here result in localized nitrogen enrichment (NO2 + NO3) that promotes hard coral dominance around 44% of the island's perimeter. Our findings show that, in the absence of confounding direct human impacts, the spatial organization of coral reef benthic competitors are predictable and somewhat bounded across the seascape by concurrent gradients in physical drivers. 相似文献
104.
105.
Tohno S Tohno Y Masuda M Minami T Moriwake Y Utsumi M Yamada M 《Biological trace element research》1999,70(3):233-241
It is known that a large quantity of magnesium contains bones, and the magnesium contents in spongy bones decrease gradually
with advancing age. To elucidate the relationships between a decrease of mineral contents in human bones and an accumulation
of minerals in the other human tissues, the content of magnesium was analyzed by inductively coupled plasma-atomic emission
spectrometry among human bones, arteries, veins, and cartilages in 27 subjects (17 men and 10 women). These were resected
from the subjects who died in the age range 40–98 yr. Calcanei were chosen for analysis of magnesium contents in contrast
with femoral, popliteal, and common carotid arteries, internal jugular and femoral veins, superior and inferior venae cavae,
and pubic symphyses.
The magnesium contents in the calcanei decreased gradually with aging, whereas they increased progressively in the arteries,
veins, and pubic symphyses with aging. It was found that as the magnesium contents decreased in the calcanei, they increased
in the arteries, such as the femoral, popliteal, and common carotid arteries, whereas they decreased inversely in the veins,
such as the internal jugular and femoral veins and superior and inferior venae cavae. Furthermore, as the magnesium contents
decreased in the calcanei, they hardly changed in the pubic symphyses. These suggest that magnesium released from bones is
accompanied by accumulation of magnesium in the arteries. 相似文献
106.
107.
Naganuma T Tohno Y Yamasaki M Tohno S Azuma C Minami T Morikawa H 《Biological trace element research》2004,101(3):203-210
To elucidate compositional changes of the rami of the internal iliac artery with aging, the authors investigated age-related
changes of the calcium content in the uterine, internal pudendal, umbilical, and obturator arteries by inductively coupled
plasma-atomic emission spectrometry. After an ordinary dissection was finished, the uterine, internal pudendal, umbilical,
and obturator arteries were resected from 10 female subjects, and the internal pudendal, umbilical, and obturator arteries
were resected from 10 male subjects. The female subjects ranged in age from 52 to 96 yr, and the male subjects ranged in age
from 63 to 88 yr. The calcium content in the uterine artery began to increase in the seventies and increased markedly in the
nineties. In the internal pudendal artery, the calcium content hardly increased up to the eighties and increased significantly
in the nineties. In contrast, the calcium content did not change in both the umbilical and obturator arteries with advancing
age. It was found that the average content of calcium was the highest in the uterine artery and decreased in the order internal
pudendal, umbilical, and obturator arteries. The average content of calcium in the uterine arteries corresponded to 46-fold
the amount of the women's obturartor arteries, in which it was the lowest. In the cases of men, the average content of calcium
was higher in the order of the internal pudendal, umbilical, and obturator arteries. Regarding the average content of calcium,
the order internal pudendal, umbilical, and obturator arteries of the men was consistent with that of the women. 相似文献
108.
109.
We studied sequence variation in the nuclear ribosomal internal transcribed spacers (ITS-1 and ITS-2) in 111 individuals from 11 populations/localities of the sponge Crambe crambe across the core species range in the western Mediterranean Sea and Atlantic Ocean. We report the first confirmed instance of intragenomic variation in sponges. Phylogeographical, nested clade and population genetic analyses were used to elucidate the species' evolutionary history. The study revealed highly structured populations affected by restricted gene flow and isolation-by-distance. A contiguous range expansion in the whole distribution area of the sponge was inferred. Phylogenetic analyses indicate a recent origin of most sequence types that could be explained by a recent origin of the species or a by recent bottleneck event in the studied area. A recent expansion of the distribution range to the Macaronesian region from the Mediterranean Sea was also detected, suggesting that C. crambe was recently introduced from the Mediterranean Sea to the Atlantic Ocean via human-mediated transport, and that the pattern observed is not the result of a natural biogeographical relationship between these zones. 相似文献
110.
Nuclear DNA sequence variation of the internal transcribed spacer (ITS) and amplified fragment length polymorphisms (AFLPs) were used to illuminate the evolutionary history of Pritzelago alpina, a herbaceous perennial of (sub)alpine to nival habitats of the European high mountains. Maximum likelihood analysis of ITS sequences of P. alpina, Hornungia petraea and Hymenolobus procumbens (the 'Pritzelago alliance') resolved P. alpina and H. petraea as sister taxa. ITS divergence estimates support an origin for P. alpina in the Late Tertiary, while intraspecific diversification started in the Late Quaternary (0.4-0.9 million years ago). AFLP analysis of 76 individuals of P. alpina, representing 24 localities across its entire west-east distribution, identified four mountain lineages in Cantabria, the Pyrenees, (south-) western Alps, and northeastern Alps/Tatras/Carpathians. In an analysis of molecular variance (amova), 14.3% of the total variation derived from this separation. However, relationships among these lineages remained unresolved in neighbour-joining and principal co-ordinates analyses, suggesting a population history of near simultaneous vicariance. Comparison with our previous ITS/AFLP study of Anthyllis montana (Fabaceae) indicates that the two co-distributed but altitudinally differentiated plant species exhibit temporally concordant but spatially discordant patterns of genetic variation. Moreover, levels of AFLP divergence were significantly lower in P. alpina than in the submediterranean, lower-elevation A. montana. Together, these data are consistent with a 'displacement refugia model', which predicts that European mountain plant species associated with lower- and upper-elevation habitats had a different cycle of range contraction into (long-term) glacial and (short-term) interglacial refugia, respectively. 相似文献