APPLICATION OF CHRONIC IN-SITU TOXICITY TESTING TO SUPPORT AN INNOVATIVE SITE-SPECIFIC AMMONIA CRITERION FOR SALT CREEK, NEBRASKA

2001 ◽  
Vol 2001 (12) ◽  
pp. 714-719
Author(s):  
W.J. Rue ◽  
R. Connelly ◽  
K. Dixon ◽  
W. McCulloch ◽  
L. Christensen ◽  
...  
Keyword(s):  
Toxicity Testing ◽  
Site Specific ◽  
Salt Creek

To Eliminate Curtain Effect of FIB TEM Samples by a Combination of Sample Dicing and Backside Milling

2014 ◽  
Author(s):  
Jian-Shing Luo ◽  
Hsiu Ting Lee
Keyword(s):  
Sample Preparation ◽  
Focused Ion Beam ◽  
Preparation Method ◽  
Low Cost ◽  
Ion Beam ◽  
Sample Preparation Method ◽  
Site Specific ◽  
Dual Beam ◽  
Transmission Electron

Abstract Several methods are used to invert samples 180 deg in a dual beam focused ion beam (FIB) system for backside milling by a specific in-situ lift out system or stages. However, most of those methods occupied too much time on FIB systems or requires a specific in-situ lift out system. This paper provides a novel transmission electron microscopy (TEM) sample preparation method to eliminate the curtain effect completely by a combination of backside milling and sample dicing with low cost and less FIB time. The procedures of the TEM pre-thinned sample preparation method using a combination of sample dicing and backside milling are described step by step. From the analysis results, the method has applied successfully to eliminate the curtain effect of dual beam FIB TEM samples for both random and site specific addresses.

Molecular modulation of calcium oxalate crystallization

2006 ◽  
Vol 291 (6) ◽  
pp. F1123-F1132 ◽  
Author(s):  
James J. De Yoreo ◽  
S. Roger Qiu ◽  
John R. Hoyer
Keyword(s):  
Molecular Modeling ◽  
Calcium Oxalate ◽  
Stone Formation ◽  
Energy Levels ◽  
Critical Role ◽  
Specific Interactions ◽  
Crystal Surfaces ◽  
Site Specific

Calcium oxalate monohydrate (COM) is the primary constituent of the majority of renal stones. Osteopontin (OPN), an aspartic acid-rich urinary protein, and citrate, a much smaller molecule, are potent inhibitors of COM crystallization at levels present in normal urine. Current concepts of the role of site-specific interactions in crystallization derived from studies of biomineralization are reviewed to provide a context for understanding modulation of COM growth at a molecular level. Results from in situ atomic force microscopy (AFM) analyses of the effects of citrate and OPN on growth verified the critical role of site-specific interactions between these growth modulators and individual steps on COM crystal surfaces. Molecular modeling investigations of interactions of citrate with steps and faces on COM crystal surfaces provided links between the stereochemistry of interaction and the binding energy levels that underlie mechanisms of growth modification and changes in overall crystal morphology. The combination of in situ AFM and molecular modeling provides new knowledge that will aid rationale design of therapeutic agents for inhibition of stone formation.

scholarly journals Prohormone convertases 1/3 and 2 together orchestrate the site-specific cleavages of progastrin to release gastrin-34 and gastrin-17

2008 ◽  
Vol 415 (1) ◽  
pp. 35-43 ◽  
Author(s):  
Jens F. Rehfeld ◽  
Xiaorong Zhu ◽  
Christina Norrbom ◽  
Jens R. Bundgaard ◽  
Anders H. Johnsen ◽  
...  
Keyword(s):  
Structural Factors ◽  
Cleavage Sites ◽  
Wild Type ◽  
Prohormone Convertases ◽  
Site Specific ◽  
G Cells ◽  
Processing Site ◽  
Vitro Effect

Cellular synthesis of peptide hormones requires PCs (prohormone convertases) for the endoproteolysis of prohormones. Antral G-cells synthesize the most gastrin and express PC1/3, 2 and 5/6 in the rat and human. But the cleavage sites in progastrin for each PC have not been determined. Therefore, in the present study, we measured the concentrations of progastrin, processing intermediates and α-amidated gastrins in antral extracts from PC1/3-null mice and compared the results with those in mice lacking PC2 and wild-type controls. The expression of PCs was examined by immunocytochemistry and in situ hybridization of mouse G-cells. Finally, the in vitro effect of recombinant PC5/6 on progastrin and progastrin fragments containing the relevant dibasic cleavage sites was also examined. The results showed that mouse G-cells express PC1/3, 2 and 5/6. The concentration of progastrin in PC1/3-null mice was elevated 3-fold. Chromatography showed that cleavage of the Arg36Arg37 and Arg73Arg74 sites were grossly decreased. Accordingly, the concentrations of progastrin products were markedly reduced, α-amidated gastrins (-34 and -17) being 25% of normal. Lack of PC1/3 was without effect on the third dibasic site (Lys53Lys54), which is the only processing site for PC2. Recombinant PC5/6 did not cleave any of the dibasic processing sites in progastrin and fragments containing the relevant dibasic processing sites. The complementary cleavages of PC1/3 and 2, however, suffice to explain most of the normal endoproteolysis of progastrin. Moreover, the results show that PCs react differently to the same dibasic sequences, suggesting that additional structural factors modulate the substrate specificity.

scholarly journals 3D magnetic patterning in additive manufacturing via site-specific in-situ alloy modification

2020 ◽  
Vol 18 ◽  
pp. 100512 ◽  
Author(s):  
Ariyan Arabi-Hashemi ◽  
Xavier Maeder ◽  
Renato Figi ◽  
Claudia Schreiner ◽  
Seth Griffiths ◽  
...  
Keyword(s):  
Additive Manufacturing ◽  
Site Specific

scholarly journals Site Specific Cryo-FIB Preparations Aimed at in situ Cryo-Electron Tomography

2017 ◽  
Vol 23 (S1) ◽  
pp. 250-251
Author(s):  
Julia Mahamid ◽  
Jan Arnold ◽  
Jurgen M. Plitzko
Keyword(s):  
Electron Tomography ◽  
Site Specific ◽  
Cryo Electron Tomography

Efficacy of soluble sodium tripolyphosphate amendments for the in-situ immobilisation of uranium

2007 ◽  
Vol 4 (5) ◽  
pp. 293 ◽  
Author(s):  
Dawn M. Wellman ◽  
Eric M. Pierce ◽  
Michelle M. Valenta
Keyword(s):  
United States ◽  
Drinking Water ◽  
Sodium Tripolyphosphate ◽  
The United States ◽  
Water Soluble ◽  
Column Experiments ◽  
Site Specific ◽  
Water Saturated ◽  
Phosphate Compounds

Environmental context. Contamination of groundwater and sediments by heavy metals and radioactive metals is a significant problem within the United States Department of Energy complex as a result of past nuclear operations. One way to remediate these metals is through reaction with phosphate compounds, which can immobilise the metals by forming highly stable metal phosphate compounds. Long-chain, water-soluble phosphate compounds provide a means to inject phosphate into subsurface contaminant plumes, to precipitate metal ions from solution. Results presented here illustrate that application of a soluble sodium tripolyphosphate to sediment contaminated with uranium will rapidly reduce the concentration of uranium in the pore water to concentrations near or below drinking water limits under water-saturated and unsaturated conditions. Abstract. A series of conventional water-saturated and pressurised unsaturated flow column experiments were conducted to evaluate the effects of using soluble polyphosphate amendments for in-situ, subsurface remediation of uranium. Experiments were conducted under mildly alkaline, calcareous conditions, representative of conditions commonly encountered at sites across the arid western United States. Results presented here illustrate that application of a soluble polyphosphate amendment to sediment contaminated with uranium will rapidly reduce the concentration of uranium released to the porewater to near or below drinking water limits under water-saturated and -unsaturated conditions. Column experiments conducted in the absence of polyphosphate illustrate sustained release of aqueous uranium at concentrations well above drinking water standards in excess of over 25 pore volumes under water-saturated conditions and over 50 pore volumes under unsaturated conditions. In the presence of tripolyphosphate, the concentration of aqueous uranium released from the sediment was below drinking water limits within 10 to 35 pore volumes under water-saturated and unsaturated conditions, respectively. Moreover, results indicate the necessity of conducting site-specific dynamic tests to tailor phosphate-based remediation technology to site specific geochemical and hydrological conditions.

scholarly journals Investigating temporal field sampling strategies for site-specific calibration of three soil moisture–neutron intensity parameterisation methods

2015 ◽  
Vol 19 (7) ◽  
pp. 3203-3216 ◽  
Author(s):  
J. Iwema ◽  
R. Rosolem ◽  
R. Baatz ◽  
T. Wagener ◽  
H. R. Bogena
Keyword(s):  
Remote Sensing ◽  
Soil Moisture ◽  
Satellite Remote Sensing ◽  
Cosmic Ray ◽  
Sampling Strategies ◽  
Site Specific ◽  
Neutron Intensity ◽  
Soil Wetness ◽  
Semi Arid

Abstract. The Cosmic-Ray Neutron Sensor (CRNS) can provide soil moisture information at scales relevant to hydrometeorological modelling applications. Site-specific calibration is needed to translate CRNS neutron intensities into sensor footprint average soil moisture contents. We investigated temporal sampling strategies for calibration of three CRNS parameterisations (modified N0, HMF, and COSMIC) by assessing the effects of the number of sampling days and soil wetness conditions on the performance of the calibration results while investigating actual neutron intensity measurements, for three sites with distinct climate and land use: a semi-arid site, a temperate grassland, and a temperate forest. When calibrated with 1 year of data, both COSMIC and the modified N0 method performed better than HMF. The performance of COSMIC was remarkably good at the semi-arid site in the USA, while the N0mod performed best at the two temperate sites in Germany. The successful performance of COSMIC at all three sites can be attributed to the benefits of explicitly resolving individual soil layers (which is not accounted for in the other two parameterisations). To better calibrate these parameterisations, we recommend in situ soil sampled to be collected on more than a single day. However, little improvement is observed for sampling on more than 6 days. At the semi-arid site, the N0mod method was calibrated better under site-specific average wetness conditions, whereas HMF and COSMIC were calibrated better under drier conditions. Average soil wetness condition gave better calibration results at the two humid sites. The calibration results for the HMF method were better when calibrated with combinations of days with similar soil wetness conditions, opposed to N0mod and COSMIC, which profited from using days with distinct wetness conditions. Errors in actual neutron intensities were translated to average errors specifically to each site. At the semi-arid site, these errors were below the typical measurement uncertainties from in situ point-scale sensors and satellite remote sensing products. Nevertheless, at the two humid sites, reduction in uncertainty with increasing sampling days only reached typical errors associated with satellite remote sensing products. The outcomes of this study can be used by researchers as a CRNS calibration strategy guideline.

Photochemically-Driven Methods for the In Situ and Site-Specific Fabrication of Monolithic-Based Electrochromatographic Microsystems

2013 ◽  
Vol 543 ◽  
pp. 227-230
Author(s):  
Violetta Georgiadou ◽  
Mohamed Guerrouache ◽  
Claudia Zlotea ◽  
Catherine Dendrinou-Samara ◽  
M. Latroche ◽  
...  
Keyword(s):  
Surface Functionalization ◽  
Site Specific ◽  
Capillary Channel ◽  
Free Radical Photopolymerization ◽  
Ethylene Dimethacrylate ◽  
On Line ◽  
Synthesis Methodology ◽  
Line Analysis ◽  
Grafting Procedure

This paper reports on the in-situ synthesis of reactive polymeric monolith and its subsequent surface functionalization. Poly (N-acryloyloxysuccinimide-co-ethylene dimethacrylate) was prepared through free radical photopolymerization of the respective monomers. The grafting procedure is based on the preliminary grafting of alkyne units on the monolith surface and the further radical photoaddition of functional thiol molecules. Implementation of UV-driven polymerization and grafting methods enabled the locally controlled immobilization of generic monolith within the confines of the capillary channel, and the site-specific immobilization of ligands on the pore surface of the monolith. Our results suggest that such a synthesis methodology is promising for integrating multiple analytical modules within microstructures for on-line analysis.

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