Spatial and Temporal Dynamics in the Relationship of Phytoplankton Biomass and Limnological Variables in a Small Artificial Lake

2010 ◽  
Author(s):  
Feipeng Li ◽  
Haiping Zhang ◽  
Yiping Zhu ◽  
Ling Chen ◽  
Jianfu Zhao ◽  
...  
Keyword(s):  
Phytoplankton Biomass ◽  
Temporal Dynamics ◽  
Artificial Lake ◽  
Spatial And Temporal Dynamics ◽  
Relationship Of ◽  
The Relationship

scholarly journals Relationship of the BOLD Signal with VEP for Ultrashort Duration Visual Stimuli (0.1 to 5 ms) in Humans

2009 ◽  
Vol 30 (2) ◽  
pp. 449-458 ◽  
Author(s):  
Barış Yeşilyurt ◽  
Kevin Whittingstall ◽  
Kâmil Uğurbil ◽  
Nikos K Logothetis ◽  
Kâmil Uludağ
Keyword(s):  
Brain Function ◽  
Temporal Dynamics ◽  
Visual Stimulation ◽  
Impulse Response Function ◽  
Blood Oxygenation ◽  
Context Dependency ◽  
Oxygenation Level ◽  
Relationship Of ◽  
The Relationship ◽  
The Brain

There is currently a great interest to combine electroencephalography (EEG) and functional magnetic resonance imaging (fMRI) to study brain function. Earlier studies have shown different EEG components to correlate well with the fMRI signal arguing for a complex relationship between both measurements. In this study, using separate EEG and fMRI measurements, we show that (1) 0.1 ms visual stimulation evokes detectable hemodynamic and visual-evoked potential (VEP) responses, (2) the negative VEP deflection at ∼80 ms (N2) co-varies with stimulus duration/intensity such as with blood oxygenation level-dependent (BOLD) response; the positive deflection at ∼120 ms (P2) does not, and (3) although the N2 VEP–BOLD relationship is approximately linear, deviation is evident at the limit of zero N2 VEP. The latter finding argues that, although EEG and fMRI measurements can co-vary, they reflect partially independent processes in the brain tissue. Finally, it is shown that the stimulus-induced impulse response function (IRF) at 0.1 ms and the intrinsic IRF during rest have different temporal dynamics, possibly due to predominance of neuromodulation during rest as compared with neurotransmission during stimulation. These results extend earlier findings regarding VEP–BOLD coupling and highlight the component- and context-dependency of the relationship between evoked potentials and hemodynamic responses.

scholarly journals Tryptophan metabolic profile in term and preterm breast milk: implications for health

2018 ◽  
Vol 7 ◽  
Author(s):  
Louise O'Rourke ◽  
Gerard Clarke ◽  
Aoife Nolan ◽  
Claire Watkins ◽  
Timothy G. Dinan ◽  
...  
Keyword(s):  
Breast Milk ◽  
Temporal Dynamics ◽  
Maternity Hospital ◽  
Meso Scale Discovery ◽  
Tnf Α ◽  
Expressed Breast Milk ◽  
Infant Neurodevelopment ◽  
Relationship Of ◽  
The Relationship ◽  
Breast Fed

AbstractBreast milk is the only source of the essential amino acid tryptophan (TRP) in breast-fed infants. Low levels of TRP could have implications for infant neurodevelopment. The objectives of the present study were to compare the relationship of TRP and its neuroactive pathway metabolites kynurenine (Kyn) and kynurenic acid (KynA) in preterm and term expressed breast milk (EBM) in the first 14 d following birth, and the relationship of TRP metabolism to maternal stress and immune status. A total of twenty-four mothers were recruited from Cork University Maternity Hospital: twelve term (>38 weeks) and twelve preterm (<35 weeks). EBM samples were collected on days 7 and 14. Free TRP, Kyn and KynA were measured using HPLC, total TRP using MS, cytokines using the Meso Scale Discovery (MSD) assay system, and cortisol using a cortisol ELISA kit. Although total TRP was higher in preterm EBM in comparison with term EBM (P< 0·05), free TRP levels were lower (P< 0·05). Kyn, KynA and the Kyn:TRP ratio increased significantly in term EBM from day 7 to day 14 (P< 0·05), but not in preterm EBM. TNF-α, IL-6 and IL-8 were higher in day 7 preterm and term EBM in comparison with day 14. There were no significant differences between term and preterm EBM cortisol levels. Increased availability of total TRP, lower levels of free TRP and alterations in the temporal dynamics of TRP metabolism in preterm compared with term EBM, coupled with higher EBM inflammatory markers on day 7, may have implications for the neurological development of exclusively breast-fed preterm infants.

scholarly journals SPECTROPHOTOPOLARIMETRY AS A METHOD FOR DETERMINING THE TIME DYNAMICS OF CHANGES IN THE MORPHOLOGICAL STRUCTURE OF MUSCLE TISSUE

2021 ◽  
Vol 2 ◽  
pp. 41-46
Author(s):  
Olexandr Harazdiuk ◽  
Nataliia Kozan ◽  
Viktor Kryvetskyi ◽  
Oleksandr Dunaiev
Keyword(s):  
Muscle Tissue ◽  
Temporal Dynamics ◽  
Morphological Structure ◽  
Biological Tissues ◽  
Human Muscle ◽  
Optical Parameters ◽  
Tissue Samples ◽  
Time Dynamics ◽  
Relationship Of ◽  
The Relationship

Introduction: The article presents the current state of issues regarding the diagnosis of pathological conditions for forensic medical experts, in particular the study of normal muscle tissue and in the presence of hemorrhages. Particular attention is paid to biophysical research methods with evidence-based accuracy, objectivity, reproducibility, and rapid results. Objectives: The purpose of the research was to study the possibilities of using spectrophotopolyarimetric methods to analyze and determine the relationship of morphological structure of biological tissues with the temporal dynamics of changes in their optical parameters, to establish the possibility of differentiating necrotic changes and signs of damage by applying Mueller matrices of human muscle tissue samples. Results: During the study, we found a number of features and patterns of change in the properties of the laser beam as a result of passing through biological tissue. Polarization-correlation methods provide new, objective information about the dynamics of change in laser polarimetric imaging of morphological structure of biological tissues. By analyzing the statistical distributions of the ellipticity of polarization of laser images of normal human muscle tissue and in the presence of hemorrhages, the possibility of identifying the relationship between the development of statistically significant changes with increasing time of death and the possibility of differentiating them are considered. Conclusion: Based on these results, we can conclude that employing laser polarization methods will allow us to open new doors in the study of the biological tissues of the human body. The results showed the effectiveness of the studied methodology and the prospect of further research in this direction.

Cosmopolitan Place, Postcolonial Time, and the Politics of Modernism in Teju Cole’s Open City

2017 ◽  
Vol 65 (1) ◽  
Author(s):  
Jens Elze
Keyword(s):  
Temporal Dynamics ◽  
Stylistic Analysis ◽  
Spatial And Temporal Dynamics ◽  
The Relationship

AbstractThis paper sets out to address larger questions about the relationship between postcolonialism, cosmopolitanism, and modernism from a stylistic analysis of the spatial and temporal dynamics of Teju Cole’s

The relationship of the scleractinian corals to the rugose corals

Paleobiology ◽  
1980 ◽  
Vol 6 (02) ◽  
pp. 146-160 ◽  
Author(s):  
William A. Oliver
Keyword(s):  
Critical Points ◽  
Scleractinian Corals ◽  
Convincing Evidence ◽  
Early Triassic ◽  
Rugose Corals ◽  
History Of ◽  
The Subject ◽  
Relationship Of ◽  
The Relationship ◽  
Biologic Factors

The Mesozoic-Cenozoic coral Order Scleractinia has been suggested to have originated or evolved (1) by direct descent from the Paleozoic Order Rugosa or (2) by the development of a skeleton in members of one of the anemone groups that probably have existed throughout Phanerozoic time. In spite of much work on the subject, advocates of the direct descent hypothesis have failed to find convincing evidence of this relationship. Critical points are:(1) Rugosan septal insertion is serial; Scleractinian insertion is cyclic; no intermediate stages have been demonstrated. Apparent intermediates are Scleractinia having bilateral cyclic insertion or teratological Rugosa.(2) There is convincing evidence that the skeletons of many Rugosa were calcitic and none are known to be or to have been aragonitic. In contrast, the skeletons of all living Scleractinia are aragonitic and there is evidence that fossil Scleractinia were aragonitic also. The mineralogic difference is almost certainly due to intrinsic biologic factors.(3) No early Triassic corals of either group are known. This fact is not compelling (by itself) but is important in connection with points 1 and 2, because, given direct descent, both changes took place during this only stage in the history of the two groups in which there are no known corals.

Skeletal elements of crinoid echinoderms: High-resolution structural and microanalytical results

1983 ◽  
Vol 41 ◽  
pp. 194-195
Author(s):  
D. F. Blake ◽  
L. F. Allard ◽  
D. R. Peacor
Keyword(s):  
High Resolution ◽  
Marine Invertebrates ◽  
Sea Urchins ◽  
Structural Features ◽  
Sea Stars ◽  
High Resolution Tem ◽  
Relationship Of ◽  
The Relationship ◽  
Insight Into

Echinodermata is a phylum of marine invertebrates which has been extant since Cambrian time (c.a. 500 m.y. before the present). Modern examples of echinoderms include sea urchins, sea stars, and sea lilies (crinoids). The endoskeletons of echinoderms are composed of plates or ossicles (Fig. 1) which are with few exceptions, porous, single crystals of high-magnesian calcite. Despite their single crystal nature, fracture surfaces do not exhibit the near-perfect {10.4} cleavage characteristic of inorganic calcite. This paradoxical mix of biogenic and inorganic features has prompted much recent work on echinoderm skeletal crystallography. Furthermore, fossil echinoderm hard parts comprise a volumetrically significant portion of some marine limestones sequences. The ultrastructural and microchemical characterization of modern skeletal material should lend insight into: 1). The nature of the biogenic processes involved, for example, the relationship of Mg heterogeneity to morphological and structural features in modern echinoderm material, and 2). The nature of the diagenetic changes undergone by their ancient, fossilized counterparts. In this study, high resolution TEM (HRTEM), high voltage TEM (HVTEM), and STEM microanalysis are used to characterize tha ultrastructural and microchemical composition of skeletal elements of the modern crinoid Neocrinus blakei.

Studies on Leukemogenic and Sarcomagenic Viruses

1970 ◽  
Vol 28 ◽  
pp. 156-157
Author(s):  
Leon Dmochowski
Keyword(s):  
Electron Microscopy ◽  
Electron Microscope ◽  
Morphological Properties ◽  
Mode Of Development ◽  
Relationship Of ◽  
The Relationship

Electron microscopy has proved to be an invaluable discipline in studies on the relationship of viruses to the origin of leukemia, sarcoma, and other types of tumors in animals and man. The successful cell-free transmission of leukemia and sarcoma in mice, rats, hamsters, and cats, interpreted as due to a virus or viruses, was proved to be due to a virus on the basis of electron microscope studies. These studies demonstrated that all the types of neoplasia in animals of the species examined are produced by a virus of certain characteristic morphological properties similar, if not identical, in the mode of development in all types of neoplasia in animals, as shown in Fig. 1.

The relationship of IGE receptor topography to signaling activity in RBL-2H3 mast cells

1991 ◽  
Vol 49 ◽  
pp. 236-237
Author(s):  
J.R. Pfeiffer ◽  
J.C. Seagrave ◽  
C. Wofsy ◽  
J.M. Oliver
Keyword(s):  
Mast Cells ◽  
Protein A ◽  
Scattered Electron ◽  
Ige Receptor ◽  
Receptor Complexes ◽  
Ige Binding ◽  
Electron Imaging ◽  
Small Clusters ◽  
Relationship Of ◽  
The Relationship

In RBL-2H3 rat leukemic mast cells, crosslinking IgE-receptor complexes with anti-IgE antibody leads to degranulation. Receptor crosslinking also stimulates the redistribution of receptors on the cell surface, a process that can be observed by labeling the anti-IgE with 15 nm protein A-gold particles as described in Stump et al. (1989), followed by back-scattered electron imaging (BEI) in the scanning electron microscope. We report that anti-IgE binding stimulates the redistribution of IgE-receptor complexes at 37“C from a dispersed topography (singlets and doublets; S/D) to distributions dominated sequentially by short chains, small clusters and large aggregates of crosslinked receptors. These patterns can be observed (Figure 1), quantified (Figure 2) and analyzed statistically. Cells incubated with 1 μg/ml anti-IgE, a concentration that stimulates maximum net secretion, redistribute receptors as far as chains and small clusters during a 15 min incubation period. At 3 and 10 μg/ml anti-IgE, net secretion is reduced and the majority of receptors redistribute rapidly into clusters and large aggregates.

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