PAH concentration gradients and fluxes through sand cap test cells installed in situ over river sediments containing coal tar

2013 ◽  
Vol 15 (8) ◽  
pp. 1601 ◽  
Author(s):  
Yong Sang Kim ◽  
Leila M. Nyberg ◽  
Byron Jenkinson ◽  
Chad T. Jafvert
Keyword(s):  
Coal Tar ◽  
River Sediments ◽  
Concentration Gradients ◽  
Test Cells ◽  
Sand Cap

An in Situ Electron Microscope Study of Cellulolytic Bacteria in River Sediments

1972 ◽  
Vol 7 (1) ◽  
pp. 66-70
Author(s):  
G.G. Leppard ◽  
M. Gochnauer ◽  
D.J. Kushner
Keyword(s):  
Electron Microscope ◽  
Microscope Study ◽  
Electron Microscope Study ◽  
River Sediments ◽  
Cellulolytic Bacteria

A novel in-situ model for continuous observation of transient drug concentration gradients across buccal epithelium at the microscopical level

1996 ◽  
Vol 39 (1) ◽  
pp. 71-78 ◽  
Author(s):  
A.J. Hoogstraate ◽  
C. Cullander ◽  
J.F. Nagelkerke ◽  
F. Spies ◽  
J. Verhoef ◽  
...  
Keyword(s):  
Drug Concentration ◽  
Buccal Epithelium ◽  
Continuous Observation ◽  
Concentration Gradients ◽  
Microscopical Level

Assessment of in situ solvent extraction for remediation of coal tar sites: Column studies

1995 ◽  
Vol 67 (1) ◽  
pp. 4-15 ◽  
Author(s):  
Sujoy B. Roy ◽  
David A. Dzombak ◽  
M. Ashraf Ali
Keyword(s):  
Solvent Extraction ◽  
Coal Tar ◽  
Column Studies

In Situ Anaerobic PCB Dechlorination and Aerobic PCB Biodegradation in Hudson River Sediments

2020 ◽  
pp. 27-43
Author(s):  
Daniel A. Abramowicz ◽  
John F. Brown ◽  
Mark R. Harkness ◽  
Michael K. O’Donnell
Keyword(s):  
River Sediments ◽  
Hudson River ◽  
Pcb Dechlorination ◽  
Pcb Biodegradation

Intracellular diffusion gradients of O2 and ATP

1986 ◽  
Vol 250 (5) ◽  
pp. C663-C675 ◽  
Author(s):  
D. P. Jones
Keyword(s):  
Mathematical Modeling ◽  
High Flux ◽  
Concentration Gradients ◽  
Electron Microscopic ◽  
Intracellular Diffusion ◽  
Metabolite Concentrations ◽  
Major Factors ◽  
Atp Supply ◽  
Endogenous Enzymes

Endogenous enzymes with different subcellular localizations provide in situ probes to study O2 and ATP concentration at various sites within cells. Results from this approach indicate that substantial intracellular concentration gradients occur under some O2- and ATP-limited conditions. These studies, along with electron microscopic analyses and mathematical modeling, indicate that clustering and distribution of mitochondria are major factors in determining the magnitude and location of the concentration gradients. The mitochondria appear to be clustered in sites of high ATP demand to maximize ATP supply under conditions of limited production. The size of such clusters is limited by the magnitude of the O2 gradient needed to provide adequate O2 concentrations for mitochondrial function within the clusters. Thus microheterogeneity of metabolite concentrations can occur in cells without membranal compartmentation and may be important in determining the rates of various high-flux processes.

scholarly journals Active transport of brilliant blue FCF across the Drosophila midgut and Malpighian tubule epithelia

2019 ◽  
Author(s):  
Dawson B.H. Livingston ◽  
Hirva Patel ◽  
Andrew Donini ◽  
Heath A. MacMillan
Keyword(s):  
Traumatic Injury ◽  
Malpighian Tubule ◽  
Malpighian Tubules ◽  
Brilliant Blue ◽  
Barrier Dysfunction ◽  
Concentration Gradients ◽  
Barrier Disruption ◽  
Brilliant Blue Fcf ◽  
Summary Statement

AbstractUnder conditions of stress, many animals suffer from epithelial barrier disruption that can cause molecules to leak down their concentration gradients, potentially causing a loss of organismal homeostasis, further injury or death. Drosophila is a common insect model, used to study barrier disruption related to aging, traumatic injury, or environmental stress. Net leak of a non-toxic dye (Brilliant blue FCF) from the gut lumen to the hemolymph is often used to identify barrier failure under these conditions, but Drosophila are capable of actively transporting structurally-similar compounds. Here, we examined whether cold stress (like other stresses) causes Brilliant blue FCF (BB-FCF) to appear in the hemolymph of flies fed the dye, and if so whether Drosophila are capable of clearing this dye from their body following chilling. Using in situ midgut leak and transport assays as well as Ramsay assays of Malpighian tubule transport, we tested whether these ionoregulatory epithelia can actively transport BB-FCF. In doing so, we found that the Drosophila midgut and Malpighian tubules can mobilize BB-FCF via an active transcellular pathway, suggesting that elevated concentrations of the dye in the hemolymph may occur from increased paracellular permeability, reduced transcellular clearance, or both.Summary StatementDrosophila are able to actively secrete Brilliant blue FCF, a commonly used marker of barrier dysfunction

Photothermal Deflection Spectroscopy Investigations of Uranium Electrochemistry - II

1993 ◽  
Vol 333 ◽  
Author(s):  
James D. Rudnicki ◽  
Richard E. Russo
Keyword(s):  
Optical Absorption ◽  
Saturated Calomel Electrode ◽  
Sample Surface ◽  
Oxidation Potential ◽  
Dissolution Mechanism ◽  
Concentration Gradients ◽  
Photothermal Deflection Spectroscopy ◽  
Photothermal Deflection ◽  
Oxide Electrochemistry

ABSTRACTPhotothermal Deflection Spectroscopy (PDS) has been applied to the study of uranium oxide electrochemistry. PDS measures the optical absorption of the sample surface and concentration gradients formed in the electrolyte. Both of these measurements are performed in situ under dynamic conditions. The combination of these two measurements provides information that can be used to infer the mechanism of the UO2 surface chemistry. These studies of the uranium dissolution mechanism are performed in pH 10.5 sodium sulfate electrolytes at 22°C. The electrolytes are free from oxygen, and complexing species. Our results suggest that dissolution of UO2 can occur at oxidizing potentials as low as -300 mV vs. saturated calomel electrode (SCE). The optical absorption and concentration gradient results provide evidence for a substantial surface change that occurs at an oxidation potential of +300 mV. The results show that the surface layer formed by this change dissolves slowly by a non-electrochemical reaction.

scholarly journals Alumina Membrane with Hour-Glass Shaped Nanochannels: Tunable Ionic Current Rectification Device Modulated by Ions Gradient

2014 ◽  
Vol 2014 ◽  
pp. 1-10 ◽  
Author(s):  
Shengnan Hou ◽  
Qinqin Wang ◽  
Xia Fan ◽  
Zhaoyue Liu ◽  
Jin Zhai
Keyword(s):  
Ionic Current ◽  
Concentration Gradients ◽  
Alumina Membrane ◽  
Promising Candidate ◽  
Ion Flow ◽  
Pore Opening ◽  
Current Rectification ◽  
Specific Alumina ◽  
And Diffusion

A new alumina membrane with hour-glass shaped nanochannels is reported using the double-side anodization method and the subsequently in situ pore opening procedure, which is applied to develop the tunable ionic current rectification devices that were modulated by ions gradient. By regulating the pH gradient, tunable ionic current rectification properties which are mainly dependent on the asymmetric surface charge density or polarity distribution on the inner walls of the nanochannels can be obtained. The enhanced ionic current rectification properties were presented due to the synergistic effect of the voltage driven ion flow and diffusion driven ion flow with the application of pH and electrolyte concentration gradients. Therefore, such specific alumina nanochannels would be considered as a promising candidate for building bioinspired artificial ion channel systems.

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