scholarly journals Assessing analytical convolution effects in diffusion studies: Applications to experimental and natural diffusion profiles

PLoS ONE ◽  
2020 ◽  
Vol 15 (11) ◽  
pp. e0241788
Author(s):  
Michael C. Jollands
Keyword(s):  
Analytical Techniques ◽  
Analytical Technique ◽  
Matlab Code ◽  
Beam Geometry ◽  
True Profile ◽  
Diffusion Studies ◽  
Concentration Changes ◽  
User Friendly ◽  
Diffusion Profiles

Given that all in-situ analytical techniques have a non-zero beam size, all measured profiles, resulting from diffusion or otherwise, will be artefactually elongated to some degree. Profiles where the total length over which the concentration changes approaches the resolution of the analytical technique likely suffer from serious convolution; the measured profiles may be considerably elongated relative to the true profile. Resolving this effect is non-trivial, except for some specific combinations of profile type and beam geometry. In this study, a versatile method for numerically deconvoluting diffusion profiles acquired using techniques with Gaussian, Lorentzian, (pseudo-)Voigt, circular/elliptical or square/rectangular interaction volumes, is presented. A MATLAB code, including a user-friendly interface (PACE-the Program for Assessing Convolution Effects in diffusion studies), is also provided, and applied to several experimental and natural profiles interpreted as resulting from diffusion, showing various degrees of convolution.

EDXRF Spectrometry and Complementary Non-Destructive Analytical Techniques in the Archaeometric Study of Copper Artefacts

2019 ◽  
Vol 15 (7) ◽  
pp. 776-787 ◽  
Author(s):  
Christos S. Katsifas ◽  
George A. Zachariadis
Keyword(s):  
Analytical Techniques ◽  
Molecular Techniques ◽  
In Situ Analysis ◽  
Related Case ◽  
Analytical Technique ◽  
Non Invasive ◽  
Portable Instruments ◽  
Non Destructive

Background: For more than a decade, Energy Dispersive X-Ray Fluorescence (EDXRF) spectrometry is the primary analytical technique in archaeometric research and especially in the study of ancient copper artefacts. EDXRF has established itself as the fundamental archaeometric analytical technique because of features like: the ability to analyze samples in a non destructive or non invasive way, no requirements for sample preparation, portability, in situ analysis, simultaneous determination of many elements and finally its easy in use. At the same time there is an explosion of related research publications which provide new possibilities to museums and archaeology scientists. On the other hand, due to its limitations it cannot provide information for every analytical question. Objective: The goal of this article is to present an overview of the capabilities of the contemporary EDXRF spectrometry for the study of ancient copper artifacts and the necessity to be implemented, depending on the analytical question, in correlation with complementary analytical techniques which are presented through related case studies. Conclusion: The demand for studying artefacts in situ, the evolution of the instrumentation and the access of more scientists (historians, archaeologists, curators etc.) to archaeometry will maintain EDXRF spectrometry as the central analytical technique. Limitations like inability for light elements detection, penetration depth, low (relatively) sensitivity can be partially overcome with the implementation of other analytical techniques which will provide complementary information. Moreover, progress in non-invasive analysis and new portable instruments combining elemental and molecular techniques expand significantly the capabilities of in situ analysis.

The Use of Advanced Analytical Techniques for Characterization of the Chemical, Physical, and Crystallographic Nature of a Surface

1973 ◽  
Vol 31 ◽  
pp. 132-133 ◽  
Author(s):  
R. E. Herfert
Keyword(s):  
Surface Characterization ◽  
Analytical Techniques ◽  
X Ray Diffraction ◽  
Depth Of Penetration ◽  
X Ray ◽  
The Past ◽  
Transmission Electron ◽  
Scanning Electron

Studies of the nature of a surface, either metallic or nonmetallic, in the past, have been limited to the instrumentation available for these measurements. In the past, optical microscopy, replica transmission electron microscopy, electron or X-ray diffraction and optical or X-ray spectroscopy have provided the means of surface characterization. Actually, some of these techniques are not purely surface; the depth of penetration may be a few thousands of an inch. Within the last five years, instrumentation has been made available which now makes it practical for use to study the outer few 100A of layers and characterize it completely from a chemical, physical, and crystallographic standpoint. The scanning electron microscope (SEM) provides a means of viewing the surface of a material in situ to magnifications as high as 250,000X.

A very rapid in situ Kikuchi technique to determine relative crystal misorientation

1988 ◽  
Vol 46 ◽  
pp. 830-831
Author(s):  
J. I. Bennetch
Keyword(s):  
Electron Beam ◽  
Analytical Techniques ◽  
Superplastic Forming ◽  
The Other ◽  
Kikuchi Pattern ◽  
Kikuchi Line ◽  
Line Analysis

In a recent study of the superplastic forming (SPF) behavior of certain Al-Li-X alloys, the relative misorientation between adjacent (sub)grains proved to be an important parameter. It is well established that the most accurate way to determine misorientation across boundaries is by Kikuchi line analysis. However, the SPF study required the characterization of a large number of (sub)grains in each sample to be statistically meaningful, a very time-consuming task even for comparatively rapid Kikuchi analytical techniques.In order to circumvent this problem, an alternate, even more rapid in-situ Kikuchi technique was devised, eliminating the need for the developing of negatives and any subsequent measurements on photographic plates. All that is required is a double tilt low backlash goniometer capable of tilting ± 45° in one axis and ± 30° in the other axis. The procedure is as follows. While viewing the microscope screen, one merely tilts the specimen until a standard recognizable reference Kikuchi pattern is centered, making sure, at the same time, that the focused electron beam remains on the (sub)grain in question.

Justifying the data analytical choice in single case research in relation to the expected data pattern

2019 ◽  
Author(s):  
Rumen Manolov
Keyword(s):  
Data Analysis ◽  
Visual Analysis ◽  
Multilevel Models ◽  
Single Case ◽  
Analytical Techniques ◽  
Real Data ◽  
Small Scale ◽  
Data User ◽  
Single Case Research ◽  
User Friendly

The lack of consensus regarding the most appropriate analytical techniques for single-case experimental designs data requires justifying the choice of any specific analytical option. The current text mentions some of the arguments, provided by methodologists and statisticians, in favor of several analytical techniques. Additionally, a small-scale literature review is performed in order to explore if and how applied researchers justify the analytical choices that they make. The review suggests that certain practices are not sufficiently explained. In order to improve the reporting regarding the data analytical decisions, it is proposed to choose and justify the data analytical approach prior to gathering the data. As a possible justification for data analysis plan, we propose using as a basis the expected the data pattern (specifically, the expectation about an improving baseline trend and about the immediate or progressive nature of the intervention effect). Although there are multiple alternatives for single-case data analysis, the current text focuses on visual analysis and multilevel models and illustrates an application of these analytical options with real data. User-friendly software is also developed.

Recent Developments in CE-MS Based Metabolomics

2020 ◽  
Vol 16 ◽  
Author(s):  
Mustafa Çelebier ◽  
Merve Nenni
Keyword(s):  
Sample Preparation ◽  
Scientific Information ◽  
Analytical Techniques ◽  
Living Organism ◽  
Analytical Technique ◽  
Ionic Compounds ◽  
Recent Sample ◽  
Recent Developments ◽  
Endogenous Metabolites ◽  
Preparation Techniques

Background: Metabolomics has gained importance in clinical applications over the last decade. Metabolomics studies are significant because the systemic metabolome is directly affected by disease conditions. Metabolome-based biomarkers are actively being developed for early diagnosis and to indicate the stage of specific diseases. Additionally, understanding the effect of an intervention on a living organism at the molecular level is a crucial strategy for understanding novel or unexpected biological processes. Results: The simultaneous improvements in advanced analytical techniques, sample preparation techniques, computer technology, and databank contents has enabled more valuable scientific information to be gained from metabolomics than ever before. With over 15,000 known endogenous metabolites, there is no single analytical technique capable of analyzing the whole metabolome. However, capillary electrophoresis-mass spectrometry (CE-MS) is a unique technique used to analyze an important portion of metabolites not accessible by liquid chromatography or gas chromatography techniques. The analytical capability of CE, combined with recent sample preparation techniques focused on extracting polar-ionic compounds, make CE-MS a perfect technique for metabolomic studies. Conclusion: Here, previous reviews of CE-MS based metabolomics are evaluated to highlight recent improvements in this technique. Specifically, we review papers from the last two years (2018 and 2019) on CE-MS based metabolomics. The current situation and the challenges facing metabolomic studies are discussed to reveal the high potential of CE-MS for further studies, especially in biomarker development studies.

In situ Fe isotopic analyses of fourteen reference materials using a synthetic Cr standard for mass bias and isobaric interference corrections by femtosecond LA-MC-ICP-MS

2021 ◽  
Author(s):  
Lei Xu ◽  
Wen Zhang ◽  
Tao Luo ◽  
Jin-Hui Yang ◽  
Zhaochu Hu
Keyword(s):  
Reference Materials ◽  
Isotope Ratios ◽  
Isobaric Interference ◽  
Analytical Technique ◽  
Mass Bias ◽  
Icp Ms ◽  
Isotopic Analyses

High precise and accurate measurements of Fe isotope ratios for fourteen reference materials from the USGS, MPI-DING and CGSG were successfully carried out using a developed analytical technique by fs...

scholarly journals Mycotoxin Analysis: New Proposals for Sample Treatment

2014 ◽  
Vol 2014 ◽  
pp. 1-12 ◽  
Author(s):  
Natalia Arroyo-Manzanares ◽  
José F. Huertas-Pérez ◽  
Ana M. García-Campaña ◽  
Laura Gámiz-Gracia
Keyword(s):  
Raw Materials ◽  
Animal Health ◽  
Analytical Techniques ◽  
Sample Treatment ◽  
Analytical Technique ◽  
Chemical Structures ◽  
Technical Developments ◽  
Food And Feed ◽  
Ultrahigh Performance Liquid Chromatography ◽  
Food Commodities

Mycotoxins are toxic secondary metabolites produced by different fungi, with different chemical structures. Mycotoxins contaminate food, feed, or raw materials used in their production and cause diseases and disorders in humans and livestock. Because of their great variety of toxic effects and their extreme heat resistance, the presence of mycotoxins in food and feed is considered a high risk to human and animal health. In order to ensure food quality and health consumers, European legislation has set maximum contents of some mycotoxins in different matrices. However, there are still some food commodities susceptible to fungal contamination, which were not contemplated in this legislation. In this context, we have developed new analytical techniques for the multiclass determination of mycotoxins in a great variety of food commodities (some of them scarcely studied), such as cereals, pseudocereals, cereal syrups, nuts, edible seeds, and botanicals. Considering the latest technical developments, ultrahigh performance liquid chromatography coupled to tandem mass spectrometry has been chosen as an efficient, fast, and selective powerful analytical technique. In addition, alternative sample treatments based on emerging methodologies, such as dispersive liquid-liquid microextraction and QuEChERS, have been developed, which allow an increased efficiency and sample throughput, as well as reducing contaminant waste.

scholarly journals Commentary on Ivancic et al.: Enzyme kinetics from circular dichroism of insulin reveals mechanistic insights into the regulation of insulin-degrading enzyme

2018 ◽  
Vol 38 (6) ◽  
Author(s):  
Giuseppe Grasso
Keyword(s):  
Analytical Techniques ◽  
Label Free ◽  
Insulin Degrading Enzyme ◽  
Degrading Enzyme ◽  
Analytical Technique ◽  
Biochemical Pathways ◽  
New Methods ◽  
The World ◽  
Free Environment ◽  
Enormous Number

Despite the enormous number of therapeutic advances in medicine, nowadays many diseases are still incurable, mainly due to the lack of knowledge of the pathological biochemical pathways triggering those diseases. For this reason, it is compulsory for the scientific community to investigate and unveil the biomolecular mechanisms responsible for the development of those diseases, such as Alzheimer’s disease and diabetes, which are widespread all over the world. In this scenario, it is of paramount importance to develop new analytical techniques and experimental procedures that are capable to make the above-mentioned investigations feasible. These new methods should allow easy performable analysis carried out in a label-free environment, in order to give reliable answers to specific biochemical questions. A recent paper published on Bioscience Reports by Ivancic et al. (https://doi.org/10.1042/BSR20181416) proposes a new analytical technique capable to reveal some mechanistic insights into the regulation of insulin-degrading enzyme (IDE), a protein involved in the above-mentioned diseases. IDE is a multifaceted enzyme having different and not well-defined roles in the cell, but it is primarily a proteolytic enzyme capable to degrade several different amyloidogenic substrates involved in different diseases. Moreover, many molecules are responsible for IDE activity modulation so that understanding how IDE activity is regulated represents a very challenging analytical task. The new analytical approach proposed by Ivancic et al. reports on the possibility to study IDE activity in an unbiased and label-free manner, representing a valid alternative assay for the investigation of any proteases degradative activity.

Near-infrared spectroscopy as a potential method for routine sediment analysis to improve rapidity and efficiency

1998 ◽  
Vol 37 (6-7) ◽  
pp. 181-188 ◽  
Author(s):  
Diane F. Malley
Keyword(s):  
Near Infrared ◽  
Organic Matter Content ◽  
Aggregate Size ◽  
Clay Content ◽  
Analytical Techniques ◽  
Matter Content ◽  
Near Infrared Reflectance ◽  
Organic C ◽  
Analytical Technique ◽  
Sediment Analysis

The potential for improvement in the rapidity, cost-effectiveness, and efficiency of sediment analysis by the application of near-infrared reflectance spectroscopy (NIRS) is recognized. The rapid (<2 min), non-chemical, non-destructive analytical technique of near-infrared (700–2500 nm) spectroscopy combines applied spectroscopy and complex statistics. It has been used for the experimental analysis of various constituents and functions of soils since the 1960s, and applications for the analysis of sediments are currently being explored. For application of NIRS, sediment samples require little preparation, other than drying, and the samples are not subject to the manipulations of conventional analytical techniques. The spectral information recorded in a 2 min scan can be used to predict numerous constituents and parameters on the samples once appropriate calibration equations have been prepared from sets of samples analyzed by both NIRS and conventional analytical techniques. Constituents and properties of soil and/or sediment analyzed by NIRS technology include moisture, organic matter content, organic C, CO3=, N, P, S, K, Ca, Mg, clay content, humic acids, lignin, cellulose, metal oxides, heavy metals, aggregate size, and inferred past pH of lakes. Several areas are identified where further research is needed to prepare for the application of NIRS to the routine analysis of sediments.

scholarly journals Formulation and evaluation of in-situ gels enriched with Tropicamide loaded solid lipid nanoparticles

2018 ◽  
Vol 9 (1) ◽  
pp. 216
Author(s):  
Jayachandra Reddy Peddappi Reddigari ◽  
Yerikala Ramesh ◽  
Chandrasekhar B. Kothapalli
Keyword(s):  
Solid Lipid Nanoparticles ◽  
Research Work ◽  
Particle Morphology ◽  
Entrapment Efficiency ◽  
Adhesive Force ◽  
Lipid Nanoparticles ◽  
Solid Lipid ◽  
Diffusion Studies

The present research work “Formulation and Evaluation of In-situ gels enriched with Tropicamide loaded solid lipid nanoparticles”. To overcome the problems of side effects and to increase the bioavailability of tropicamide loaded solid lipid nanoparticles are containing with suitable lipids (glycerin trimyristate, Tristearin, Phosphatidylcholine & soyabean lecithin) with stabilizers (poloxamer 188) and surfactant like polysorbate 80. The interaction between drug, lipids & polymer by performing with FTIR no incompatibility with each other. The particle morphology was carried out by SEM & AFM in solid lipid nanoparticle formulation. The particle size was ranges from 213.6 ± 2.16nm to 538.0 ± 6.53 nm. The zeta potential ranges form -18.3mV to 25.6mV. The entrapment efficiency of free tropicamide was ranges from 74.13 % to 90.17%. The drug content was ranges from 0.212mg/ml to 0.912mg/ml. The SLN formulations must be transparent white colour and semi solid consistency. The pH 7.0 to 8.0 in all formulation. The gelling strength of gels TSLNGF1 to TSLNGF12 was ranges from 72 ± 1 sec to 117 ± 2 sec. The bio adhesive force was ranges from 10.12 ±1.01 dynes/cm2 to 23.12 ± 1.91 dynes/cm2. The viscosity of prepared formulation ranges from 415 ± 1.94 cps to 652 ± 1.41 cps. The spread ability studies of all formulation were ranges from 09 gms/sec to 18 gms/sec. The Accelerated stability the formulations does not undergo any chemical Changes. In vitro Franz’s diffusion studies of SLN enriched in gels TSLNGF1 to TSLNGF12 among the various formulation best formulations was TSLNGF6; its follows first order kinetics. Keywords: Solid Lipid Nanoparticles; Tropicamide; In- situ gels; In vitro diffusion studies

Sign in / Sign up

Export Citation Format

Share Document