Optimization of Surface Properties for Nanoindentation Studies on Nuclear Structural Materials

2017 ◽  
Vol 891 ◽  
pp. 67-72
Author(s):  
Petra Bublíková ◽  
Hygreeva Kiran Namburi ◽  
Daniela Marušáková
Keyword(s):  
Mechanical Properties ◽  
Sample Preparation ◽  
Radiation Damage ◽  
High Sensitivity ◽  
Structural Materials ◽  
Thin Layers ◽  
Standard Methods ◽  
Electrolytic Polishing ◽  
Preparation Step ◽  
Extent Of Damage

Nanoindentation using static loading of indenter tip is one of versatile methods used for evaluation of materials in smaller volume. It includes investigation of structural phases and thin layers on substrates etc. In the field of nuclear core and structural materials, nanoindentation has become an important tool to assess mechanical properties and correlate to the level of radiation damage at elevated and room temperatures. Nanoindentation, ideally in combination with Transmission Electron Microscopy, can describe the extent of damage and behaviour from the nanoand micro scale. Due to the high sensitivity of nanoindentation system, that typically uses loads in the range of tens of nN up to several tens of mN, the precise sample preparation is challenging and to be performed especially to understand behaviour of bulk materials. In the current study, samples from Austenitic Stainless Steel (ASS) 321, which is the representative structural material used for reactor internals, were prepared by standard methods - fine polishing, chemical etching, electrolytic etching, electrolytic polishing, electrolytic polishing & etching and ion polishing. Firstly, non-irradiated samples were used for optimization of the sample preparation methodology and then it will be applied on irradiated samples to obtain local mechanical properties. After each preparation step, nanoindentation was performed and load was optimized leading to the minimum standard deviation, also taking into account an indent size and pile-up mechanism. Scanning Probe Microscopy (SPM imaging) and nanoindentation results showed the multi-grained austenitic structure with minimal roughness. Local mechanical properties can be measured according to the knowledge of radiation damage type and location, with focus on grain boundaries to be evaluated. This study shows that advanced methods such as ion polishing are not suitable for ASS preparation, but standard methods based on chemical reaction with structure, especially electrolytic polishing and etching, are highly recommended.

Metallic Nanoneedles Arrays for TEM Sample Preparation “Lift-Out”

2012 ◽  
Author(s):  
Romaneh Jalilian ◽  
David Mudd ◽  
Neil Torrez ◽  
Jose Rivera ◽  
Mehdi M. Yazdanpanah ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Electron Microscope ◽  
Sample Preparation ◽  
Focused Ion Beam ◽  
Ion Beam ◽  
Beam System ◽  
Transmission Electron ◽  
Nanoneedle Array ◽  
Superior Mechanical Properties ◽  
And Performance

Abstract The sample preparation for transmission electron microscope can be done using a method known as "lift-out". This paper demonstrates a method of using a silver-gallium nanoneedle array for a quicker sharpening process of tungsten probes with better sample viewing, covering the fabrication steps and performance of needle-tipped probes for lift-out process. First, an array of high aspect ratio silver-gallium nanoneedles was fabricated and coated to improve their conductivity and strength. Then, the nanoneedles were welded to a regular tungsten probe in the focused ion beam system at the desired angle, and used as a sharp probe for lift-out. The paper demonstrates the superior mechanical properties of crystalline silver-gallium metallic nanoneedles. Finally, a weldless lift-out process is described whereby a nano-fork gripper was fabricated by attaching two nanoneedles to a tungsten probe.

scholarly journals A Single LC-MS/MS Analysis to Quantify CoA Biosynthetic Intermediates and Short-Chain Acyl CoAs

Metabolites ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 468
Author(s):  
Anthony E. Jones ◽  
Nataly J. Arias ◽  
Aracely Acevedo ◽  
Srinivasa T. Reddy ◽  
Ajit S. Divakaruni ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Sample Preparation ◽  
Biosynthetic Pathway ◽  
Solid Phase ◽  
High Sensitivity ◽  
Short Chain ◽  
Extraction Column ◽  
Chain Acyl ◽  
Precision And Accuracy ◽  
Mass Spectrometry Mass Spectrometry

Coenzyme A (CoA) is an essential cofactor for dozens of reactions in intermediary metabolism. Dysregulation of CoA synthesis or acyl CoA metabolism can result in metabolic or neurodegenerative disease. Although several methods use liquid chromatography coupled with mass spectrometry/mass spectrometry (LC-MS/MS) to quantify acyl CoA levels in biological samples, few allow for simultaneous measurement of intermediates in the CoA biosynthetic pathway. Here we describe a simple sample preparation and LC-MS/MS method that can measure both short-chain acyl CoAs and biosynthetic precursors of CoA. The method does not require use of a solid phase extraction column during sample preparation and exhibits high sensitivity, precision, and accuracy. It reproduces expected changes from known effectors of cellular CoA homeostasis and helps clarify the mechanism by which excess concentrations of etomoxir reduce intracellular CoA levels.

Investigation of Phenolic Content in Five Different Pine Barks Species Grown in Turkey by HPLC-UV and LC–MS

2021 ◽  
Author(s):  
Mehmet Emin Şeker ◽  
Ali Çelik ◽  
Kenan Dost ◽  
Ayşegül Erdoğan
Keyword(s):  
Sample Preparation ◽  
Orthophosphoric Acid ◽  
Phenolic Content ◽  
Reversed Phase ◽  
Uv Detector ◽  
Epicatechin Gallate ◽  
Rp Hplc ◽  
Phenolic Constituents ◽  
Preparation Step ◽  
Very High

Abstract Investigation of phenolic content from different pine bark species grown in Turkey was performed using a reversed-phase high pressure liquid chromatography with ultraviolet (RP-HPLC-UV) method. All phenolic constituents were separated in <26 min on reversed-phase C18 column with gradient mobile phase that consists of orthophosphoric acid, methanol and acetonitrile. Detections were made on an UV detector at 280 nm and at a flow rate of 1 mL/min. Samples were prepared according to Masqueller’s conventional sample preparation method with slight modifications. To avoid the reduction in extraction efficiency the sample preparation step was carried out under argon atmosphere. The linearity of the method was between 0.9994 and 0.9999. The detection limits for the five phenolic constituents ranged from 0122 to 0.324 mg/L. Catechin and taxifolin were found in all pine barks at a concentration of 0.065 ± 0.002–1.454 ± 0.004 and 0.015 ± 0.001–23.164 ± 0.322 mg/g, respectively. Epicatechin was determined in four pine barks between 0.027 ± 0.001 and 0.076 ± 0.002 mg/g, ferulic acid in two pine barks between 0.010 ± 0.001 and 0.022 ± 0.001 mg/g and epicatechin gallate in only one of the pine barks at 0.025 ± 0.001 mg/g. Finally, the total amount of phenolic compounds and antioxidant capacities of the pine barks were found to be very high.

scholarly journals Author Correction: The influence of different sample preparation on mechanical properties of human iliotibial tract

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Benjamin Fischer ◽  
Sascha Kurz ◽  
Andreas Höch ◽  
Stefan Schleifenbaum
Keyword(s):  
Mechanical Properties ◽  
Sample Preparation ◽  
Iliotibial Tract

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

scholarly journals Rapid and Sensitive Quantification of Intracellular Glycyl-Sarcosine for Semi-High-Throughput Screening for Inhibitors of PEPT-1

Pharmaceutics ◽  
2021 ◽  
Vol 13 (7) ◽  
pp. 1019
Author(s):  
Teresa von Linde ◽  
Gzona Bajraktari-Sylejmani ◽  
Walter E. Haefeli ◽  
Jürgen Burhenne ◽  
Johanna Weiss ◽  
...  
Keyword(s):  
Sample Preparation ◽  
High Throughput ◽  
High Throughput Screening ◽  
Dynamic Range ◽  
High Sensitivity ◽  
Peptide Bond ◽  
Peptide Transporter ◽  
Systemic Absorption ◽  
Screening Assay ◽  
Limit Of Quantification

The peptide transporter PEPT-1 (SLC15A1) plays a major role in nutritional supply with amino acids by mediating the intestinal influx of dipeptides and tripeptides generated during food digestion. Its role in the uptake of small bioactive peptides and various therapeutics makes it an important target for the investigation of the systemic absorption of small peptide-like active compounds and prodrug strategies of poorly absorbed therapeutics. The dipeptide glycyl-sarcosine (Gly-Sar), which comprises an N-methylated peptide bond that increases stability against enzymatic degradation, is widely utilized for studying PEPT-1-mediated transport. To support experiments on PEPT-1 inhibitor screening to identify potential substrates, we developed a highly sensitive Gly-Sar quantification assay for Caco-2 cell lysates with a dynamic range of 0.1 to 1000 ng/mL (lower limit of quantification 0.68 nM) in 50 µL of cell lysate. The assay was validated following the applicable recommendations for bioanalytic method validation of the FDA and EMA. Sample preparation and quantification were established in 96-well cell culture plates that were also used for the cellular uptake studies, resulting in a rapid and robust screening assay for PEPT-1 inhibitors. This sample preparation principle, combined with the high sensitivity of the UPLC-MS/MS quantification, is suitable for screening assays for PEPT-1 inhibitors and substrates in high-throughput formats and holds the potential for automation. Applicability was demonstrated by IC50 determinations of the known PEPT-1 inhibitor losartan, the known substrates glycyl-proline (Gly-Pro), and valaciclovir, the prodrug of aciclovir, which itself is no substrate of PEPT-1 and consequently showed no inhibition in our assay.

Technique development of high-throughput and high-sensitivity sample preparation and separation for proteomics

Bioanalysis ◽  
2021 ◽  
Author(s):  
Zhenbin Zhang ◽  
Minyang Zheng ◽  
Yufen Zhao ◽  
Perry G Wang
Keyword(s):  
Sample Preparation ◽  
High Throughput ◽  
High Sensitivity ◽  
Proteomics Analysis ◽  
Comprehensive Review ◽  
Proteomics Research ◽  
Quantification Accuracy ◽  
Technique Development

Sample preparation and separation methods determine the sensitivity and the quantification accuracy of the proteomics analysis. This article covers a comprehensive review of the recent technique development of high-throughput and high-sensitivity sample preparation and separation methods in proteomics research.

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