AFM tip-sample convolution effects for cylinder protrusions

Science.gov (United States)

Shen, Jian; Zhang, Dan; Zhang, Fei-Hu; Gan, Yang

2017-11-01

A thorough understanding about the AFM tip geometry dependent artifacts and tip-sample convolution effect is essential for reliable AFM topographic characterization and dimensional metrology. Using rigid sapphire cylinder protrusions (diameter: 2.25 μm, height: 575 nm) as the model system, a systematic and quantitative study about the imaging artifacts of four types of tips-two different pyramidal tips, one tetrahedral tip and one super sharp whisker tip-is carried out through comparing tip geometry dependent variations in AFM topography of cylinders and constructing the rigid tip-cylinder convolution models. We found that the imaging artifacts and the tip-sample convolution effect are critically related to the actual inclination of the working cantilever, the tip geometry, and the obstructive contacts between the working tip's planes/edges and the cylinder. Artifact-free images can only be obtained provided that all planes and edges of the working tip are steeper than the cylinder sidewalls. The findings reported here will contribute to reliable AFM characterization of surface features of micron or hundreds of nanometers in height that are frequently met in semiconductor, biology and materials fields.

Nonlinear Phenomena in the Single-Mode Dynamics in an AFM Cantilever Beam

KAUST Repository

Ruzziconi, Laura

2016-12-05

profiles and integrity charts are drawn. The curves of constant percentage of integrity measure are detected, highlighting that they provide valuable quantitative information about the changes in the structural safety. Robustness as well as vulnerability to disturbances is examined. The practical range of existence of each branch is observed to be smaller, and sometimes remarkably smaller than the theoretical one. The issue of the dynamical integrity analysis in the AFM design is addressed, showing that these curves may be used to establish safety factors in order to operate the AFM according to the desired outcome, depending on the expected disturbances. Physical meaning and practical relevance of the nonlinear phenomena in the AFM engineering design are discussed.

PREFACE: Non-contact AFM Non-contact AFM

Science.gov (United States)

Giessibl, Franz J.; Morita, Seizo

2012-02-01

This special issue is focussed on high resolution non-contact atomic force microscopy (AFM). Non-contact atomic force microscopy was established approximately 15 years ago as a tool to image conducting and insulating surfaces with atomic resolution. Since 1998, an annual international conference has taken place, and although the proceedings of these conferences are a useful source of information, several key developments warrant devoting a special issue to this subject. In the theoretic field, the possibility of supplementing established techniques such as scanning tunneling microscopy (STM) and Kelvin probe microscopy with atomically resolved force micrsoscopy poses many challenges in the calculation of contrast and contrast reversal. The surface science of insulators, self-assembled monolayers and adsorbates on insulators is a fruitful field for the application of non-contact AFM: several articles in this issue are devoted to these subjects. Atomic imaging and manipulation have been pioneered using STM, but because AFM allows the measurement of forces, AFM has had a profound impact in this field as well. Three-dimensional force spectroscopy has allowed many important insights into surface science. In this issue a combined 3D tunneling and force microscopy is introduced. Non-contact AFM typically uses frequency modulation to measure force gradients and was initially used mainly in a vacuum. As can be seen in this issue, frequency modulation is now also used in ambient conditions, allowing better spatial and force resolution. We thank all of the contributors for their time and efforts in making this special issue possible. We are also very grateful to the staff of IOP Publishing for handling the administrative aspects and for steering the refereeing process. Non-contact AFM contents Relation between the chemical force and the tunnelling current in atomic point contacts: a simple model Pavel Jelínek, Martin Ondrácek and Fernando Flores Theoretical simulation of

Noise in NC-AFM measurements with significant tip–sample interaction

Directory of Open Access Journals (Sweden)

Jannis Lübbe

2016-12-01

Full Text Available The frequency shift noise in non-contact atomic force microscopy (NC-AFM imaging and spectroscopy consists of thermal noise and detection system noise with an additional contribution from amplitude noise if there are significant tip–sample interactions. The total noise power spectral density DΔf(fm is, however, not just the sum of these noise contributions. Instead its magnitude and spectral characteristics are determined by the strongly non-linear tip–sample interaction, by the coupling between the amplitude and tip–sample distance control loops of the NC-AFM system as well as by the characteristics of the phase locked loop (PLL detector used for frequency demodulation. Here, we measure DΔf(fm for various NC-AFM parameter settings representing realistic measurement conditions and compare experimental data to simulations based on a model of the NC-AFM system that includes the tip–sample interaction. The good agreement between predicted and measured noise spectra confirms that the model covers the relevant noise contributions and interactions. Results yield a general understanding of noise generation and propagation in the NC-AFM and provide a quantitative prediction of noise for given experimental parameters. We derive strategies for noise-optimised imaging and spectroscopy and outline a full optimisation procedure for the instrumentation and control loops.

Visual characterization and quantitative measurement of artemisinin-induced DNA breakage

Energy Technology Data Exchange (ETDEWEB)

Cai Huaihong [Bionanotechnology Lab, and Department of Chemistry, Jinan University, Guangzhou 510632 (China); Yang Peihui [Bionanotechnology Lab, and Department of Chemistry, Jinan University, Guangzhou 510632 (China)], E-mail: typh@jnu.edu.cn; Chen Jianan [Bionanotechnology Lab, and Department of Chemistry, Jinan University, Guangzhou 510632 (China); Liang Zhihong [Experiment and Technology Center, Jinan University, Guangzhou 510632 (China); Chen Qiongyu [Institute of Genetic Engineering, Jinan University, Guangzhou 510632 (China); Cai Jiye [Bionanotechnology Lab, and Department of Chemistry, Jinan University, Guangzhou 510632 (China)], E-mail: tjycai@jnu.edu.cn

2009-05-01

DNA conformational change and breakage induced by artemisinin, a traditional Chinese herbal medicine, have been visually characterized and quantitatively measured by the multiple tools of electrochemistry, UV-vis absorption spectroscopy, atomic force microscopy (AFM), and DNA electrophoresis. Electrochemical and spectroscopic results confirm that artemisinin can intercalate into DNA double helix, which causes DNA conformational changes. AFM imaging vividly demonstrates uneven DNA strand breaking induced by QHS interaction. To assess these DNA breakages, quantitative analysis of the extent of DNA breakage has been performed by analyzing AFM images. Basing on the statistical analysis, the occurrence of DNA breaks is found to depend on the concentration of artemisinin. DNA electrophoresis further validates that the intact DNA molecules are unwound due to the breakages occur at the single strands. A reliable scheme is proposed to explain the process of artemisinin-induced DNA cleavage. These results can provide further information for better understanding the anticancer activity of artemisinin.

AFM Surface Roughness and Topography Analysis of Lithium Disilicate Glass Ceramic

Directory of Open Access Journals (Sweden)

M. Pantić

2015-12-01

Full Text Available The aim of this study is presenting AFM analysis of surface roughness of Lithium disilicate glass ceramic (IPS e.max CAD under different finishing procedure (techniques: polishing, glazing and grinding. Lithium disilicate glass ceramics is all-ceramic dental system which is characterized by high aesthetic quality and it can be freely said that properties of material provide all prosthetic requirements: function, biocompatibility and aesthetic. Experimental tests of surface roughness were investigated on 4 samples with dimensions: 18 mm length, 14 mm width and 12 mm height. Contact surfaces of three samples were treated with different finishing procedure (polishing, glazing and grinding, and the contact surface of the raw material is investigated as a fourth sample. Experimental measurements were done using the Atomic Force Microscopy (AFM of NT-MDT manufacturers, in the contact mode. All obtained results of different prepared samples are presented in the form of specific roughness parameters (Rа, Rz, Rmax, Rq and 3D surface topography.

AFM imaging and fractal analysis of surface roughness of AlN epilayers on sapphire substrates

Energy Technology Data Exchange (ETDEWEB)

Dallaeva, Dinara, E-mail: dinara.dallaeva@yandex.ru [Brno University of Technology, Faculty of Electrical Engineering and Communication, Physics Department, Technická 8, 616 00 Brno (Czech Republic); Ţălu, Ştefan [Technical University of Cluj-Napoca, Faculty of Mechanical Engineering, Department of AET, Discipline of Descriptive Geometry and Engineering Graphics, 103-105 B-dul Muncii Street, Cluj-Napoca 400641, Cluj (Romania); Stach, Sebastian [University of Silesia, Faculty of Computer Science and Materials Science, Institute of Informatics, Department of Biomedical Computer Systems, ul. Będzińska 39, 41-205 Sosnowiec (Poland); Škarvada, Pavel; Tománek, Pavel; Grmela, Lubomír [Brno University of Technology, Faculty of Electrical Engineering and Communication, Physics Department, Technická 8, 616 00 Brno (Czech Republic)

2014-09-01

Graphical abstract: - Highlights: • We determined the complexity of 3D surface roughness of aluminum nitride layers. • We used atomic force microscopy and analyzed their fractal geometry. • We determined the fractal dimension of surface roughness of aluminum nitride layers. • We determined the dependence of layer morphology on substrate temperature. - Abstract: The paper deals with AFM imaging and characterization of 3D surface morphology of aluminum nitride (AlN) epilayers on sapphire substrates prepared by magnetron sputtering. Due to the effect of temperature changes on epilayer's surface during the fabrication, a surface morphology is studied by combination of atomic force microscopy (AFM) and fractal analysis methods. Both methods are useful tools that may assist manufacturers in developing and fabricating AlN thin films with optimal surface characteristics. Furthermore, they provide different yet complementary information to that offered by traditional surface statistical parameters. This combination is used for the first time for measurement on AlN epilayers on sapphire substrates, and provides the overall 3D morphology of the sample surfaces (by AFM imaging), and reveals fractal characteristics in the surface morphology (fractal analysis)

Synthesis and AFM visualization of DNA nanostructures

International Nuclear Information System (INIS)

Mizuno, Rika; Haruta, Hirotaka; Morii, Takashi; Okada, Takao; Asakawa, Takeshi; Hayashi, Kenshi

2004-01-01

We propose a novel bottom-up approach for the fabrication of various desired nanostructures, based on self-assembly of oligonucleotides governed by Watson-Crick base pairing. Using this approach, we designed Y-shaped, closed Y-shaped, H-shaped, and hexagonal structures with oligonucleotides. These structures were autonomously fabricated simply by mixing equimolar solutions of oligonucleotides and performing hybridization. After synthesis of the nanostructures, we confirmed their validity by agarose gel electrophoresis and atomic force microscope (AFM) visualization. We detected bands of the desired molecular sizes in the gel electrophoresis and observed the desired structures by AFM analysis. We concluded that the synthesized structures were consistent with our intended design and that AFM visualization is a very useful tool for the observation of nanostructures

Multifractural analysis of AFM images of Nb thin film surfaces

International Nuclear Information System (INIS)

Altajskij, M.V; Chernenko, L.P.; Balebanov, V.M.; Erokhin, N.S.; Moiseev, S.S.

2000-01-01

The multifractal analysis of the atomic Force Microscope (AFM) images of the Niobium (Nb) thin film surfaces has been performed. These Nb films are being used for the measurements of the London penetration depth of stationary magnetic field by polarized neutron reflectometry. The analysis shows the behavior of Renyi dimensions of images (in the range of available scales 6-2000 nm), like the known multifractal p-model, with typical Hausdorff dimension of prevalent color in the range of 1.6-1.9. This indicates the fractal nature of film landscape on those scales. The perspective of new mechanism of order parameter suppression on superconductor-vacuum boundary, manifested in anomalous magnetic field penetration in discussed

Neutron detection using CR-39 and Atomic Force Microscopy (AFM)

International Nuclear Information System (INIS)

Vazquez L, C.; Fragoso, R.; Felix, R.; Golzarri, J.I.; Espinosa, G.; Castillo, F.

2007-01-01

AFM has been applied in many CR-39 track formation analyses. In this paper, the use of AFM in the neutron detection and analysis of the track formation is reported. The irradiation was made with an 1.5 GBq (0.5 Ci) 241 Am-Be neutron source, with and without a polyethylene radiator. The surface analysis was made to the CR-39 fresh material without irradiation, after the irradiation, and after a very short etching time. The results show important differences between the irradiation, with and without polyethylene radiator, and the latent tracks of the neutron in the CR-39 polycarbonate. The development of track formation after very short etching time and pits characterization were measured too using the AFM facilities. (Author)

Surface features on Sahara soil dust particles made visible by atomic force microscope (AFM) phase images

OpenAIRE

G. Helas; M. O. Andreae

2008-01-01

We show that atomic force microscopy (AFM) phase images can reveal surface features of soil dust particles, which are not evident using other microscopic methods. The non-contact AFM method is able to resolve topographical structures in the nanometer range as well as to uncover repulsive atomic forces and attractive van der Waals' forces, and thus gives insight to surface properties. Though the method does not allow quantitative assignment in terms of chemical compound description, it clearly...

Accuracy optimization of high-speed AFM measurements using Design of Experiments

DEFF Research Database (Denmark)

Tosello, Guido; Marinello, F.; Hansen, Hans Nørgaard

2010-01-01

Atomic Force Microscopy (AFM) is being increasingly employed in industrial micro/nano manufacturing applications and integrated into production lines. In order to achieve reliable process and product control at high measuring speed, instrument optimization is needed. Quantitative AFM measurement...... results are influenced by a number of scan settings parameters, defining topography sampling and measurement time: resolution (number of profiles and points per profile), scan range and direction, scanning force and speed. Such parameters are influencing lateral and vertical accuracy and, eventually......, the estimated dimensions of measured features. The definition of scan settings is based on a comprehensive optimization that targets maximization of information from collected data and minimization of measurement uncertainty and scan time. The Design of Experiments (DOE) technique is proposed and applied...

Sequential electrochemical oxidation and site-selective growth of nanoparticles onto AFM probes.

Science.gov (United States)

Wang, Haitao; Tian, Tian; Zhang, Yong; Pan, Zhiqiang; Wang, Yong; Xiao, Zhongdang

2008-08-19

In this work, we reported an approach for the site-selective growth of nanoparticle onto the tip apex of an atomic force microscopy (AFM) probe. The silicon AFM probe was first coated with a self-assembled monolayer (SAM) of octadecyltrichlorosilane (OTS) through a chemical vapor deposition (CVD) method. Subsequently, COOH groups were selectively generated at the tip apex of silicon AFM probes by applying an appropriate bias voltage between the tip and a flat gold electrode. The transformation of methyl to carboxylic groups at the tip apex of the AFM probe was investigated through measuring the capillary force before and after electrochemical oxidation. To prepare the nanoparticle terminated AFM probe, the oxidized AFM probe was then immersed in an aqueous solution containing positive metal ions, for example, Ag+, to bind positive metal ions to the oxidized area (COOH terminated area), followed by chemical reduction with aqueous NaBH 4 and further development (if desired) to give a metal nanoparticle-modified AFM probe. The formation of a metal nanoparticle at the tip apex of the AFM probe was confirmed by scanning electron microscopy (SEM) and energy dispersive X-ray analysis (EDXA).

An AFM-based pit-measuring method for indirect measurements of cell-surface membrane vesicles

International Nuclear Information System (INIS)

Zhang, Xiaojun; Chen, Yuan; Chen, Yong

2014-01-01

Highlights: • Air drying induced the transformation of cell-surface membrane vesicles into pits. • An AFM-based pit-measuring method was developed to measure cell-surface vesicles. • Our method detected at least two populations of cell-surface membrane vesicles. - Abstract: Circulating membrane vesicles, which are shed from many cell types, have multiple functions and have been correlated with many diseases. Although circulating membrane vesicles have been extensively characterized, the status of cell-surface membrane vesicles prior to their release is less understood due to the lack of effective measurement methods. Recently, as a powerful, micro- or nano-scale imaging tool, atomic force microscopy (AFM) has been applied in measuring circulating membrane vesicles. However, it seems very difficult for AFM to directly image/identify and measure cell-bound membrane vesicles due to the similarity of surface morphology between membrane vesicles and cell surfaces. Therefore, until now no AFM studies on cell-surface membrane vesicles have been reported. In this study, we found that air drying can induce the transformation of most cell-surface membrane vesicles into pits that are more readily detectable by AFM. Based on this, we developed an AFM-based pit-measuring method and, for the first time, used AFM to indirectly measure cell-surface membrane vesicles on cultured endothelial cells. Using this approach, we observed and quantitatively measured at least two populations of cell-surface membrane vesicles, a nanoscale population (<500 nm in diameter peaking at ∼250 nm) and a microscale population (from 500 nm to ∼2 μm peaking at ∼0.8 μm), whereas confocal microscopy only detected the microscale population. The AFM-based pit-measuring method is potentially useful for studying cell-surface membrane vesicles and for investigating the mechanisms of membrane vesicle formation/release

Molecular dynamics simulation of AFM studies of a single polymer chain

International Nuclear Information System (INIS)

Wang Wenhai; Kistler, Kurt A.; Sadeghipour, Keya; Baran, George

2008-01-01

Single polymer chain force-extension behavior measured by Atomic Force Microscopy (AFM) was interpreted by molecular dynamics (MD) simulation performed by applying a bead-spring (coarse-graining) model in which the bond potential function between adjacent beads is described by a worm-like chain (WLC) model. Simulation results indicate that caution should be applied when interpreting experimental AFM data, because the data vary depending on the point of AFM tip-polymer chain attachment. This approach offers an effective way for eventual analysis of the mechanical behavior of complex polymer networks

Molecular dynamics simulation of AFM studies of a single polymer chain

Energy Technology Data Exchange (ETDEWEB)

Wang Wenhai [Center for Bioengineering and Biomaterials, College of Engineering, Temple University, 1947 N. 12th Street, Philadelphia, PA 19122 (United States); Kistler, Kurt A. [Department of Chemistry, Temple University, 1901 N. 13th Street, Philadelphia, PA 19122 (United States); Sadeghipour, Keya [Center for Bioengineering and Biomaterials, College of Engineering, Temple University, 1947 N. 12th Street, Philadelphia, PA 19122 (United States); Baran, George [Center for Bioengineering and Biomaterials, College of Engineering, Temple University, 1947 N. 12th Street, Philadelphia, PA 19122 (United States)], E-mail: grbaran@temple.edu

2008-11-24

Single polymer chain force-extension behavior measured by Atomic Force Microscopy (AFM) was interpreted by molecular dynamics (MD) simulation performed by applying a bead-spring (coarse-graining) model in which the bond potential function between adjacent beads is described by a worm-like chain (WLC) model. Simulation results indicate that caution should be applied when interpreting experimental AFM data, because the data vary depending on the point of AFM tip-polymer chain attachment. This approach offers an effective way for eventual analysis of the mechanical behavior of complex polymer networks.

Resonance frequencies of AFM cantilevers in contact with a surface

Energy Technology Data Exchange (ETDEWEB)

Verbiest, G.J., E-mail: Verbiest@physik.rwth-aachen.de [JARA-FIT and II. Institute of Physics, RWTH Aachen University, 52074 Aachen (Germany); Rost, M.J., E-mail: Rost@physics.leidenuniv.nl [Huygens-Kamerlingh Onnes Laboratory, Leiden University, P.O. Box 9504, 2300 RA Leiden (Netherlands)

2016-12-15

To make the forces in an Atomic Force Microscope that operates in a dynamic mode with one or multiple vibrations applied to the cantilever, quantitative, one needs to relate a change in resonance frequency of the cantilever to a specific tip–sample interaction. Due to the time dependence of the force between the tip and sample caused by the vibrations, this task is not only difficult, but in fact only possible to solve for certain limiting cases, if one follows common theoretical approaches with a Taylor expansion around the deflection point. Here, we present an analytical method for calculating the resonance frequencies of the cantilever that is valid for any tip–sample interaction. Instead of linearizing the tip–sample interaction locally, we calculate an averaged, weighted linearization taking into account all positions of the tip while vibrating. Our method bridges, therefore, the difficult gap between a free oscillating cantilever and a cantilever that is pushed infinitely hard into contact with a surface, which describes a clamped-pinned boundary condition. For a correct description of the cantilever dynamics, we take into account both the tip mass and the tip moment of inertia. Applying our model, we show that it is possible to calculate the modal response of a cantilever as a function of the tip–sample interaction strength. Based on these modal vibration characteristics, we show that the higher resonance frequencies of a cantilever are completely insensitive to the strength of the tip–sample interaction. - Highlights: • A method to calculate the resonances of AFM cantilevers under any force is proposed. • The analytical model is based on Euler-beam theory. • The shift in resonance frequency due to forces decrease with increasing mode number. • The proposed method enables quantitative ultrasound AFM experiments. • Our results explain also the applicability of the higher modes in SubSurface-AFM.

Towards easy and reliable AFM tip shape determination using blind tip reconstruction

International Nuclear Information System (INIS)

Flater, Erin E.; Zacharakis-Jutz, George E.; Dumba, Braulio G.; White, Isaac A.; Clifford, Charles A.

2014-01-01

Quantitative determination of the geometry of an atomic force microscope (AFM) probe tip is critical for robust measurements of the nanoscale properties of surfaces, including accurate measurement of sample features and quantification of tribological characteristics. Blind tip reconstruction, which determines tip shape from an AFM image scan without knowledge of tip or sample shape, was established most notably by Villarrubia [J. Res. Natl. Inst. Stand. Tech. 102 (1997)] and has been further developed since that time. Nevertheless, the implementation of blind tip reconstruction for the general user to produce reliable and consistent estimates of tip shape has been hindered due to ambiguity about how to choose the key input parameters, such as tip matrix size and threshold value, which strongly impact the results of the tip reconstruction. These key parameters are investigated here via Villarrubia's blind tip reconstruction algorithms in which we have added the capability for users to systematically vary the key tip reconstruction parameters, evaluate the set of possible tip reconstructions, and determine the optimal tip reconstruction for a given sample. We demonstrate the capabilities of these algorithms through analysis of a set of simulated AFM images and provide practical guidelines for users of the blind tip reconstruction method. We present a reliable method to choose the threshold parameter corresponding to an optimal reconstructed tip shape for a given image. Specifically, we show that the trend in how the reconstructed tip shape varies with threshold number is so regular that the optimal, or Goldilocks, threshold value corresponds with the peak in the derivative of the RMS difference with respect to the zero threshold curve vs. threshold number. - Highlights: • Blind tip reconstruction algorithms have been implemented and augmented to determine the optimal input parameters. • We demonstrate the capabilities of the algorithms using a simulated AFM

Implementing atomic force microscopy (AFM) for studying kinetics of gold nanoparticle's growth

DEFF Research Database (Denmark)

Georgiev, P.; Bojinova, A.; Kostova, B.

2013-01-01

In a novel experimental approach Atomic Force Microscopy (AFM) was applied as a tool for studying the kinetics of gold nanoparticle growth. The gold nanoparticles were obtained by classical Turkevich citrate synthesis at two different temperatures. From the analysis of AFM images during...... the synthesis process the nanoparticle s' sizes were obtained. To demonstrate the applicability and the reliability of the proposed experimental approach we studied the nanoparticles growth at two different temperatures by spectrophotometric measurements and compared them with the results from AFM experimental...

The AFm phase in Portland cement

International Nuclear Information System (INIS)

Matschei, T.; Lothenbach, B.; Glasser, F.P.

2007-01-01

The AFm phase of Portland cements refers to a family of hydrated calcium aluminates based on the hydrocalumite-like structure of 4CaO.Al 2 O 3 .13-19 H 2 O. However OH - may be replaced by SO 4 2- and CO 3 2- . Except for limited replacement (50 mol%, maximum) of sulfate by hydroxide, these compositions do not form solid solutions and, from the mineralogical standpoint, behave as separate phases. Therefore many hydrated cements will contain mixtures of AFm phases. AFm phases have been made from precursors and experimentally-determined phase relationships are depicted at 25 deg. C. Solubility data are reported and thermodynamic data are derived. The 25 deg. C stability of AFm phases is much affected by the nature of the anion: carbonate stabilises AFm and displaces OH and SO 4 at species activities commonly encountered in cement systems. However in the presence of portlandite, and as carbonate displaces sulfate in AFm, the reaction results in changes in the amount of both portlandite and ettringite: specimen calculations are presented to quantify these changes. The scheme of phase balances enables calculation of the mineralogical balances of a hydrated cement paste with greater accuracy than hitherto practicable

Characterisation of tissue factor-bearing extracellular vesicles with AFM: comparison of air-tapping-mode AFM and liquid Peak Force AFM

Directory of Open Access Journals (Sweden)

Julie Hardij

2013-08-01

Full Text Available Introduction: Extracellular vesicles (EVs are shed from cells and carry markers of the parent cells. Vesicles derived from cancer cells reach the bloodstream and locally influence important physiological processes. It has been previously shown that procoagulant vesicles are circulating in patients’ fluids. These EVs are therefore considered as promising biomarkers for the thrombotic risk. Because of their small size, classical methods such as flow cytometry suffer from limitation for their characterisation. Atomic force microscopy (AFM has been proposed as a promising complementary method for the characterisation of EVs. Objectives: The objectives of this study are: (a to develop and validate AFM with specific antibodies (anti-TF and (b to compare air and liquid modes for EVs’ size and number determination as potential biomarkers of the prothrombotic risk. Methods: AFM multimode nanoscope III was used for air tapping mode (TM. AFM catalyst was used for liquid Peak Force Tapping (PFT mode. Vesicles are generated according to Davila et al.'s protocol. Substrates are coated with various concentrations of antibodies, thanks to ethanolamine and glutaraldehyde. Results: Vesicles were immobilised on antibody-coated surfaces to select tissue factor (TF-positive vesicles. The size range of vesicles observed in liquid PFT mode is 6–10 times higher than in air mode. This corresponds to the data found in the literature. Conclusion: We recommend liquid PFT mode to analyse vesicles on 5 µg/ml antibody-coated substrates.

AFM annual report 1983 (Petroleum Industry). [Export Federation for Mineral Oil, Federal Republic of Germany]. AFM Jahresbericht 1983

Energy Technology Data Exchange (ETDEWEB)

1983-01-01

The annual report 1983 of the Export Federation for Mineral Oil (AFM) contains informations about the mineral oil economics, the market development for selected main products and the environmental protection. The AFM terms (standard conditions for barge transactions) for the mineral oil industry are given. The AFM Oil Market Report Daily has extended the frame of its reports in 1983.

Quantitative analysis chemistry

International Nuclear Information System (INIS)

Ko, Wansuk; Lee, Choongyoung; Jun, Kwangsik; Hwang, Taeksung

1995-02-01

This book is about quantitative analysis chemistry. It is divided into ten chapters, which deal with the basic conception of material with the meaning of analysis chemistry and SI units, chemical equilibrium, basic preparation for quantitative analysis, introduction of volumetric analysis, acid-base titration of outline and experiment examples, chelate titration, oxidation-reduction titration with introduction, titration curve, and diazotization titration, precipitation titration, electrometric titration and quantitative analysis.

Interactions between chitosan and cells measured by AFM

Energy Technology Data Exchange (ETDEWEB)

Hsiao, Sheng-Wen; Thien, Doan Van Hong; Ho, Ming-Hua [Department of Chemical Engineering, National Taiwan University of Science and Technology, Taipei 10617, Taiwan (China); Hsieh, Hsyue-Jen [Department of Chemical Engineering, National Taiwan University, Taipei 10617, Taiwan (China); Li, Chung-Hsing [Division of Orthodontics and Pediatric Dentistry, Department of Dentistry, Tri-Service General Hospital, Taipei, Taiwan (China); Hung, Chang-Hsiang [Department of Dentistry, Kinmen Hospital Department of Health, Taiwan (China); Li, Hsi-Hsin, E-mail: mhho@mail.ntust.edu.t [Deputy Superintendent, Kinmen Hospital Department of Health, Taiwan (China)

2010-10-01

Chitosan, a biocompatible material that has been widely used in bone tissue engineering, is believed to have a high affinity to osteoblastic cells. This research is the first to prove this hypothesis. By using atomic force microscopy (AFM) with a chitosan-modified cantilever, quantitative evaluation of the interforce between chitosan and cells was carried out. A chitosan tip functionalized with Arg-Gly-Asp (RGD) was also used to measure the interforce between RGD-chitosan and osteoblastic cells. This research concluded by examining cell adhesion and spreading of chitosan substrates as further characterization of the interactions between cells and chitosan. The force measured by AFM showed that the interforce between chitosan and osteoblasts was the highest (209 nN). The smallest adhesion force (61.8 nN) appeared between chitosan and muscle fibroblasts, which did not demonstrate any osteoblastic properties. This result proved that there was a significant interaction between chitosan and bone cells, and correlated with the observations of cell attachment and spreading. The technique developed in this research directly quantified the adhesion between chitosan and cells. This is the first study to demonstrate that specific interaction exists between chitosan and osteoblasts.

Interactions between chitosan and cells measured by AFM

International Nuclear Information System (INIS)

Hsiao, Sheng-Wen; Thien, Doan Van Hong; Ho, Ming-Hua; Hsieh, Hsyue-Jen; Li, Chung-Hsing; Hung, Chang-Hsiang; Li, Hsi-Hsin

2010-01-01

Chitosan, a biocompatible material that has been widely used in bone tissue engineering, is believed to have a high affinity to osteoblastic cells. This research is the first to prove this hypothesis. By using atomic force microscopy (AFM) with a chitosan-modified cantilever, quantitative evaluation of the interforce between chitosan and cells was carried out. A chitosan tip functionalized with Arg-Gly-Asp (RGD) was also used to measure the interforce between RGD-chitosan and osteoblastic cells. This research concluded by examining cell adhesion and spreading of chitosan substrates as further characterization of the interactions between cells and chitosan. The force measured by AFM showed that the interforce between chitosan and osteoblasts was the highest (209 nN). The smallest adhesion force (61.8 nN) appeared between chitosan and muscle fibroblasts, which did not demonstrate any osteoblastic properties. This result proved that there was a significant interaction between chitosan and bone cells, and correlated with the observations of cell attachment and spreading. The technique developed in this research directly quantified the adhesion between chitosan and cells. This is the first study to demonstrate that specific interaction exists between chitosan and osteoblasts.

Pathogen identification using peptide nanotube biosensors and impedance AFM

Science.gov (United States)

Maccuspie, Robert I.

Pathogen identification at highly sensitive levels is crucial to meet urgent needs in fighting the spread of disease or detecting bioterrorism events. Toward that end, a new method for biosensing utilizing fluorescent antibody nanotubes is proposed. Fundamental studies on the self-assembly of these peptide nanotubes are performed, as are applications of aligning these nanotubes on surfaces. As biosensors, these nanotubes incorporate recognition units with antibodies at their ends and fluorescent signaling units at their sidewalls. When viral pathogens were mixed with these antibody nanotubes in solution, the nanotubes rapidly aggregated around the viruses. The size of the aggregates increased as the concentration of viruses increased, as detected by flow cytometry on the order of attomolar concentrations by changes in fluorescence and light scattering intensities. This enabled determination of the concentrations of viruses at trace levels (102 to 106 pfu/mL) within 30 minutes from the receipt of samples to the final quantitative data analysis, as demonstrated on Adenovirus, Herpes Simplex Virus, Influenza, and Vaccinia virus. As another separate approach, impedance AFM is used to study the electrical properties of individual viruses and nanoparticles used as model systems. The design, development, and implementation of the impedance AFM for an Asylum Research platform is described, as well as its application towards studying the impedance of individual nanoparticles as a model system for understanding the fundamental science of how the life cycle of a virus affects its electrical properties. In combination, these approaches fill a pressing need to quantify viruses both rapidly and sensitively.

Two-dimensional dopant profiling for shallow junctions by TEM and AFM

International Nuclear Information System (INIS)

Yoo, K.

2000-01-01

The present work concerns the development of the Etch/TEM and Etch/AFM methods to obtain quantitative 2-D dopant profiles for the ultra shallow p-n junctions of the next generation of metal-oxide-semiconductor field effect transistors (MOSFETs). For these methods, thin foil (TEM) or bulk (AFM) cross-sectional specimens were etched using a dopant selective chemical so that local areas of the dopant implanted source/drain (S/D) regions were etched to different depths. The surface topography of the S/D regions was determined from the thickness fringes for the TEM method and by the direct measurement for the AFM method. The local etched depths were converted to etch rates, and these were then converted to corresponding 1-D and 2-D dopant profiles by the experimentally independent etch rate calibration curves. Shallow junction MOSFET samples were designed and fabricated with junction depths 60nm (n + /p), 80nm (n + /p) and 120nm (p + /n) using 0.25μm process technology. A new method using SOG (Spin-on-Glass) contributed to the high quality XTEM thin foil specimens. Controlled stirring of the etchant increased the dopant concentration selectivity and etching consistency. Computer modelling simulated the isotropic etching behaviours, which can introduce the significant error in dopant profiling for shallow and abrupt junction samples. Comprehensive quantitative results enabled the optimum etching time to be determined for the first time. Etch/TEM method gave 1-D dopant profiles that showed good agreement with 1-D Spreading Resistance Probe (SRP) dopant profiles for determining junction depths. 2-D dopant profiles gave L eff , i.e. the shortest lateral distance between the S/D junctions, of major importance for MOSFET performance. Values for L eff of 161, 159 and 123nm were determined from 60, 80 and 120nm junction depth samples respectively, compared with the 215nm MOSFET gate length. The resolution and accuracy of the Etch/TEM method are estimated as 2 and 10nm

Nano Mechanical Machining Using AFM Probe

Science.gov (United States)

Mostofa, Md. Golam

Complex miniaturized components with high form accuracy will play key roles in the future development of many products, as they provide portability, disposability, lower material consumption in production, low power consumption during operation, lower sample requirements for testing, and higher heat transfer due to their very high surface-to-volume ratio. Given the high market demand for such micro and nano featured components, different manufacturing methods have been developed for their fabrication. Some of the common technologies in micro/nano fabrication are photolithography, electron beam lithography, X-ray lithography and other semiconductor processing techniques. Although these methods are capable of fabricating micro/nano structures with a resolution of less than a few nanometers, some of the shortcomings associated with these methods, such as high production costs for customized products, limited material choices, necessitate the development of other fabricating techniques. Micro/nano mechanical machining, such an atomic force microscope (AFM) probe based nano fabrication, has, therefore, been used to overcome some the major restrictions of the traditional processes. This technique removes material from the workpiece by engaging micro/nano size cutting tool (i.e. AFM probe) and is applicable on a wider range of materials compared to the photolithographic process. In spite of the unique benefits of nano mechanical machining, there are also some challenges with this technique, since the scale is reduced, such as size effects, burr formations, chip adhesions, fragility of tools and tool wear. Moreover, AFM based machining does not have any rotational movement, which makes fabrication of 3D features more difficult. Thus, vibration-assisted machining is introduced into AFM probe based nano mechanical machining to overcome the limitations associated with the conventional AFM probe based scratching method. Vibration-assisted machining reduced the cutting forces

AFM analysis of bleaching effects on dental enamel microtopography

Energy Technology Data Exchange (ETDEWEB)

Pedreira de Freitas, Ana Carolina, E-mail: anacarolfreitas@usp.br [Departamento de Dentistica, Faculdade de Odontologia da Universidade de Sao Paulo, Av. Prof. Lineu Prestes, 2227 - Cidade Universitaria, CEP 05508-000, Sao Paulo (Brazil); Cardoso Espejo, Luciana, E-mail: luespejo@hotmail.com [Departamento de Dentistica, Faculdade de Odontologia da Universidade de Sao Paulo, Av. Prof. Lineu Prestes, 2227 - Cidade Universitaria, CEP 05508-000, Sao Paulo (Brazil); Brossi Botta, Sergio, E-mail: sbbotta@usp.br [Departamento de Dentistica, Faculdade de Odontologia da Universidade de Sao Paulo, Av. Prof. Lineu Prestes, 2227 - Cidade Universitaria, CEP 05508-000, Sao Paulo (Brazil); Sa Teixeira, Fernanda de, E-mail: nandast@if.usp.br [Laboratorio de Filmes Finos, Instituto de Fisica da Universidade de Sao Paulo, Rua do Matao, Travessa R, 187 - Cidade Universitaria, CEP 05314-970, Sao Paulo (Brazil); Cerqueira, Luz Maria Aparecida A., E-mail: maacluz@usp.br [Departamento de Dentistica, Faculdade de Odontologia da Universidade de Sao Paulo, Av. Prof. Lineu Prestes, 2227 - Cidade Universitaria, CEP 05508-000, Sao Paulo (Brazil); Garone-Netto, Narciso, E-mail: ngarone@usp.br [Departamento de Dentistica, Faculdade de Odontologia da Universidade de Sao Paulo, Av. Prof. Lineu Prestes, 2227 - Cidade Universitaria, CEP 05508-000, Sao Paulo (Brazil); Bona Matos, Adriana, E-mail: bona@usp.br [Departamento de Dentistica, Faculdade de Odontologia da Universidade de Sao Paulo, Av. Prof. Lineu Prestes, 2227 - Cidade Universitaria, CEP 05508-000, Sao Paulo (Brazil); Barbosa da Silveira Salvadori, Maria Cecilia, E-mail: mcsalva@if.usp.br [Laboratorio de Filmes Finos, Instituto de Fisica da Universidade de Sao Paulo, Rua do Matao, Travessa R, 187 - Cidade Universitaria, CEP 05314-970, Sao Paulo (Brazil)

2010-02-15

The purpose of this in vitro study was to test a new methodology to evaluate the effects of 35% hydrogen peroxide agent on the microtopography of sound enamel using an atomic force microscope (AFM). The buccal sound surfaces of three extracted human lower incisors were used, without polishing the surfaces to maintain them with natural morphology. These unpolished surfaces were subjected to bleaching procedure with 35% hydrogen peroxide that consisted of 4 applications of the bleaching agent on enamel surfaces for 10 min each application. Surface images were obtained in a 15 {mu}m x 15 {mu}m area using an AFM. The roughness (Ra and RMS) and the power spectral density (PSD) were obtained before and after the bleaching treatment. As results we could inquire that the PSD analyses were very suitable to identifying the morphological changes on the surfaces, while the Ra and RMS parameters were insufficient to represent the morphological alterations promoted by bleaching procedure on enamel. The morphological wavelength in the range of visible light spectrum (380-750 nm) was analyzed, showing a considerable increase of the PSD with the bleaching treatment.

AFM analysis of bleaching effects on dental enamel microtopography

International Nuclear Information System (INIS)

Pedreira de Freitas, Ana Carolina; Cardoso Espejo, Luciana; Brossi Botta, Sergio; Sa Teixeira, Fernanda de; Cerqueira, Luz Maria Aparecida A.; Garone-Netto, Narciso; Bona Matos, Adriana; Barbosa da Silveira Salvadori, Maria Cecilia

2010-01-01

The purpose of this in vitro study was to test a new methodology to evaluate the effects of 35% hydrogen peroxide agent on the microtopography of sound enamel using an atomic force microscope (AFM). The buccal sound surfaces of three extracted human lower incisors were used, without polishing the surfaces to maintain them with natural morphology. These unpolished surfaces were subjected to bleaching procedure with 35% hydrogen peroxide that consisted of 4 applications of the bleaching agent on enamel surfaces for 10 min each application. Surface images were obtained in a 15 μm x 15 μm area using an AFM. The roughness (Ra and RMS) and the power spectral density (PSD) were obtained before and after the bleaching treatment. As results we could inquire that the PSD analyses were very suitable to identifying the morphological changes on the surfaces, while the Ra and RMS parameters were insufficient to represent the morphological alterations promoted by bleaching procedure on enamel. The morphological wavelength in the range of visible light spectrum (380-750 nm) was analyzed, showing a considerable increase of the PSD with the bleaching treatment.

Reconstruction Algorithms in Undersampled AFM Imaging

DEFF Research Database (Denmark)

Arildsen, Thomas; Oxvig, Christian Schou; Pedersen, Patrick Steffen

2016-01-01

This paper provides a study of spatial undersampling in atomic force microscopy (AFM) imaging followed by different image reconstruction techniques based on sparse approximation as well as interpolation. The main reasons for using undersampling is that it reduces the path length and thereby...... the scanning time as well as the amount of interaction between the AFM probe and the specimen. It can easily be applied on conventional AFM hardware. Due to undersampling, it is then necessary to further process the acquired image in order to reconstruct an approximation of the image. Based on real AFM cell...... images, our simulations reveal that using a simple raster scanning pattern in combination with conventional image interpolation performs very well. Moreover, this combination enables a reduction by a factor 10 of the scanning time while retaining an average reconstruction quality around 36 dB PSNR...

LET spectrum measurements in Cr-39 PNTD with AFM

Energy Technology Data Exchange (ETDEWEB)

Johnson, Carl Edward [Los Alamos National Laboratory; De Witt, Joel M [OSU, PHYSICS; Benton, Eric R [OSU, PHYSICS; Yasuda, Nakahiro [NIRS, HIMAC; Benton, Eugene V [UNIV OF SAN FRANCISCO

2010-01-01

Energetic protons, neutrons, and heavy ions undergoing collisions with target nuclei of varying Z can produce residual heavy recoil fragments via intra-nuclear cascade/evaporation reactions. The particles produced in these non-elastic collisions generally have such extremely short range ({approx}< 10 {mu}m) that they cannot be directly observed by conventional detection methods including CR-39 plastic nuclear track detector (PNTD) that has been chemically etched for analysis by standard visible light microscopy. However, high-LET recoil fragments having range on the order of several cell diameters can be produced in tissue during radiotherapy using proton and carbon beams. We have developed a method to analyze short-range, high-LET tracks in CR-39 plastic nuclear track detector (PNTD) using short duration chemical etching ({approx}< 1 {mu}m) followed by automated atomic force microscope (AFM) scanning. The post-scan data processing used in this work was based on semi-automated matrix analysis opposed to traditional grey-scale image analysis. This method takes advantage of the 3-D data obtained via AFM to achieve robust discrimination of nuclear tracks from other features. Through automation of AFM scanning, sufficient AFM scan frames were obtained to attain an LET spectrum spanning the LET range from 200-1500 keV/{mu}m. In addition to our experiments, simulations were carried out with the Monte Carlo transport code, FLUKA. To demonstrate this method, CR-39 PNTD was exposed to the proton therapy beam at Loma Linda University Medical Center (LLUMC) at 60 and 230 MeV. Additionally, detectors were exposed to I GeV protons at the NASA Space Radiation Laboratory (NSRL) at Brookhaven National Laboratory (BNL). For these exposures CR-39 PNTD, Al and Cu target foils were used between detector layers.

LET spectrum measurements in Cr-39 PNTD with AFM

International Nuclear Information System (INIS)

Johnson, Carl Edward; DeWitt, Joel M.; Benton, Eric R.; Yasuda, Nakahiro; Benton, Eugene V.

2010-01-01

Energetic protons, neutrons, and heavy ions undergoing collisions with target nuclei of varying Z can produce residual heavy recoil fragments via intra-nuclear cascade/evaporation reactions. The particles produced in these non-elastic collisions generally have such extremely short range (∼< 10 μm) that they cannot be directly observed by conventional detection methods including CR-39 plastic nuclear track detector (PNTD) that has been chemically etched for analysis by standard visible light microscopy. However, high-LET recoil fragments having range on the order of several cell diameters can be produced in tissue during radiotherapy using proton and carbon beams. We have developed a method to analyze short-range, high-LET tracks in CR-39 plastic nuclear track detector (PNTD) using short duration chemical etching (∼< 1 μm) followed by automated atomic force microscope (AFM) scanning. The post-scan data processing used in this work was based on semi-automated matrix analysis opposed to traditional grey-scale image analysis. This method takes advantage of the 3-D data obtained via AFM to achieve robust discrimination of nuclear tracks from other features. Through automation of AFM scanning, sufficient AFM scan frames were obtained to attain an LET spectrum spanning the LET range from 200-1500 keV/μm. In addition to our experiments, simulations were carried out with the Monte Carlo transport code, FLUKA. To demonstrate this method, CR-39 PNTD was exposed to the proton therapy beam at Loma Linda University Medical Center (LLUMC) at 60 and 230 MeV. Additionally, detectors were exposed to I GeV protons at the NASA Space Radiation Laboratory (NSRL) at Brookhaven National Laboratory (BNL). For these exposures CR-39 PNTD, Al and Cu target foils were used between detector layers.

A comparison of atomic force microscopy (AFM) and dynamic light scattering (DLS) methods to characterize nanoparticle size distributions

International Nuclear Information System (INIS)

Hoo, Christopher M.; Starostin, Natasha; West, Paul; Mecartney, Martha L.

2008-01-01

This paper compares the accuracy of conventional dynamic light scattering (DLS) and atomic force microscopy (AFM) for characterizing size distributions of polystyrene nanoparticles in the size range of 20-100 nm. Average DLS values for monosize dispersed particles are slightly higher than the nominal values whereas AFM values were slightly lower than nominal values. Bimodal distributions were easily identified with AFM, but DLS results were skewed toward larger particles. AFM characterization of nanoparticles using automated analysis software provides an accurate and rapid analysis for nanoparticle characterization and has advantages over DLS for non-monodispersed solutions.

Crystallization of Probucol in Nanoparticles Revealed by AFM Analysis in Aqueous Solution.

Science.gov (United States)

Egami, Kiichi; Higashi, Kenjirou; Yamamoto, Keiji; Moribe, Kunikazu

2015-08-03

The crystallization behavior of a pharmaceutical drug in nanoparticles was directly evaluated by atomic force microscopy (AFM) force curve measurements in aqueous solution. A ternary spray-dried sample (SPD) was prepared by spray drying the organic solvent containing probucol (PBC), hypromellose (HPMC), and sodium dodecyl sulfate (SDS). The amorphization of PBC in the ternary SPD was confirmed by powder X-ray diffraction (PXRD) and solid-state 13C NMR measurements. A nanosuspension containing quite small particles of 25 nm in size was successfully prepared immediately after dispersion of the ternary SPD into water. Furthermore, solution-state 1H NMR measurements revealed that a portion of HPMC coexisted with PBC as a mixed state in the freshly prepared nanosuspension particles. After storing the nanosuspension at 25 °C, a gradual increase in the size of the nanoparticles was observed, and the particle size changed to 93.9 nm after 7 days. AFM enabled the direct observation of the morphology and agglomeration behavior of the nanoparticles in water. Moreover, AFM force-distance curves were changed from (I) to (IV), depending on the storage period, as follows: (I) complete indentation within an applied force of 1 nN, (II) complete indentation with an applied force of 1-5 nN, (III) partial indentation with an applied force of 5 nN, and (IV) nearly no indentation with an applied force of 5 nN. This stiffness increase of the nanoparticles was attributed to gradual changes in the molecular state of PBC from the amorphous to the crystal state. Solid-state 13C NMR measurements of the freeze-dried samples demonstrated the presence of metastable PBC Form II crystals in the stored nanosuspension, strongly supporting the AFM results.

Temperature-Controlled High-Speed AFM: Real-Time Observation of Ripple Phase Transitions.

Science.gov (United States)

Takahashi, Hirohide; Miyagi, Atsushi; Redondo-Morata, Lorena; Scheuring, Simon

2016-11-01

With nanometer lateral and Angstrom vertical resolution, atomic force microscopy (AFM) has contributed unique data improving the understanding of lipid bilayers. Lipid bilayers are found in several different temperature-dependent states, termed phases; the main phases are solid and fluid phases. The transition temperature between solid and fluid phases is lipid composition specific. Under certain conditions some lipid bilayers adopt a so-called ripple phase, a structure where solid and fluid phase domains alternate with constant periodicity. Because of its narrow regime of existence and heterogeneity ripple phase and its transition dynamics remain poorly understood. Here, a temperature control device to high-speed atomic force microscopy (HS-AFM) to observe dynamics of phase transition from ripple phase to fluid phase reversibly in real time is developed and integrated. Based on HS-AFM imaging, the phase transition processes from ripple phase to fluid phase and from ripple phase to metastable ripple phase to fluid phase could be reversibly, phenomenologically, and quantitatively studied. The results here show phase transition hysteresis in fast cooling and heating processes, while both melting and condensation occur at 24.15 °C in quasi-steady state situation. A second metastable ripple phase with larger periodicity is formed at the ripple phase to fluid phase transition when the buffer contains Ca 2+ . The presented temperature-controlled HS-AFM is a new unique experimental system to observe dynamics of temperature-sensitive processes at the nanoscopic level. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

AFM measurements on ferrous materials

Directory of Open Access Journals (Sweden)

Ros Yáñez, T.

2000-08-01

Full Text Available The Atomic Force Microscope (AFM has been successfully used for the characterisation of the surface topography of a very wide range of materials. The AFM is an interesting technique to study the surface of materials and specifically to study surface effects in steel, e.g. after polishing and/or after etching. This technique allows not only to study the topography of the samples, but it is also a useful tool to obtain structural details of surfaces and for the identification of different phases. In this paper, some applications are shown concerning the study of the microstructure of multiphase-steels.

El Microcopio de Fuerza Atómica (AFM es utilizado en la caracterización topográfica de una gran variedad de materiales. El AFM es una interesante técnica para el estudio de la superficie de los aceros, ya sea con ataque químico o no. Esta técnica es también una útil herramienta para obtener detalles estructurales en las superficies y en la identificación de fases. En este trabajo algunas de estas aplicaciones son mostradas en el estudio de la microestructura de aceros multifásicos.

Structural analysis of radiation-induced chromosome aberrations by atomic force microscope (AFM) before and after Giemsa staining

International Nuclear Information System (INIS)

Murakami, M.; Kanda, R.; Minamihisamatsu, M.; Hayata, I.

2003-01-01

Full text: We have studied structures of chromosome aberration induced by ionizing radiation by an atomic force microscope (AFM). The AFM could visualize the fine structure of chromosomes on Giemsa stained or unstained samples, although it was difficult to visualize unstained chromosomes by light microscope. The height data of chromosomes obtained by AFM provided useful information to describe detailed structure of chromatid gaps induced by heavy ion irradiation. A fibrous structure was observed on the unstained chromosome and these structures were considered to be the 30nm fibers on the chromosome. These types of structures were observed in the gaps as well as on surface of the chromosome. Further more, other types of chromosome aberration induced by ionizing radiation visualized by AFM will be presented

Single cell adhesion force measurement for cell viability identification using an AFM cantilever-based micro putter

Science.gov (United States)

Shen, Yajing; Nakajima, Masahiro; Kojima, Seiji; Homma, Michio; Kojima, Masaru; Fukuda, Toshio

2011-11-01

Fast and sensitive cell viability identification is a key point for single cell analysis. To address this issue, this paper reports a novel single cell viability identification method based on the measurement of single cell shear adhesion force using an atomic force microscopy (AFM) cantilever-based micro putter. Viable and nonviable yeast cells are prepared and put onto three kinds of substrate surfaces, i.e. tungsten probe, gold and ITO substrate surfaces. A micro putter is fabricated from the AFM cantilever by focused ion beam etching technique. The spring constant of the micro putter is calibrated using the nanomanipulation approach. The shear adhesion force between the single viable or nonviable cell and each substrate is measured using the micro putter based on the nanorobotic manipulation system inside an environmental scanning electron microscope. The adhesion force is calculated based on the deflection of the micro putter beam. The results show that the adhesion force of the viable cell to the substrate is much larger than that of the nonviable cell. This identification method is label free, fast, sensitive and can give quantitative results at the single cell level.

Surface features on Sahara soil dust particles made visible by atomic force microscope (AFM phase images

Directory of Open Access Journals (Sweden)

M. O. Andreae

2008-10-01

Full Text Available We show that atomic force microscopy (AFM phase images can reveal surface features of soil dust particles, which are not evident using other microscopic methods. The non-contact AFM method is able to resolve topographical structures in the nanometer range as well as to uncover repulsive atomic forces and attractive van der Waals' forces, and thus gives insight to surface properties. Though the method does not allow quantitative assignment in terms of chemical compound description, it clearly shows deposits of distinguishable material on the surface. We apply this technique to dust aerosol particles from the Sahara collected over the Atlantic Ocean and describe micro-features on the surfaces of such particles.

AFM-based identification of the dynamic properties of globular proteins: simulation study

International Nuclear Information System (INIS)

Kim, Deok Ho; Park, Jung Yul; Kim, Moon K.; Hong, Keum Shik

2008-01-01

Nowadays a mathematical model-based computational approach is getting more attention as an effective tool for understanding the mechanical behaviors of biological systems. To find the mechanical properties of the proteins required to build such a model, this paper investigates a real-time identification method based on an AFM nanomanipulation system. First, an AFM-based bio-characterization system is introduced. Second, a second-order time-varying linear model representing the interaction between an AFM cantilever and globular proteins in a solvent is presented. Finally, we address a real-time estimation method in which the results of AFM experiments are designed to be inputs of the state estimator proposed here. Our attention is restricted to a theoretical feasibility analysis of the proposed methodology. We simply set the mechanical properties of the particular protein such as mass, stiffness, and damping coefficient in the system model prior to running the simulation. Simulation results show very good agreement with the preset properties. We anticipate that the realization of the AFM-based bio-characterization system will also provide an experimental validation of the proposed identification procedure in the future. This methodology can be used to determine a model of protein motion for the purpose of computer simulation and for a real-time modification of protein deformation

Neural network approximation of tip-abrasion effects in AFM imaging

International Nuclear Information System (INIS)

Bakucz, Peter; Dziomba, Thorsten; Koenders, Ludger; Krüger-Sehm, Rolf; Yacoot, Andrew

2008-01-01

The abrasion (wear) of tips used in scanning force microscopy (SFM) directly influences SFM image quality and is therefore of great relevance to quantitative SFM measurements. The increasing implementation of automated SFM measurement schemes has become a strong driving force for increasing efforts towards the prediction of tip wear, as it needs to be ensured that the probe is exchanged before a level of tip wear is reached that adversely affects the measurement quality. In this paper, we describe the identification of tip abrasion in a system of SFM measurements. We attempt to model the tip-abrasion process as a concatenation of a mapping from the measured AFM data to a regression vector and a nonlinear mapping from the regressor space to the output space. The mapping is formed as a basis function expansion. Feedforward neural networks are used to approximate this mapping. The one-hidden layer network gave a good quality of fit for the training and test sets for the tip-abrasion system. We illustrate our method with AFM measurements of both fine periodic structures and randomly oriented sharp features and compare our neural network results with those obtained using other methods

Neural network approximation of tip-abrasion effects in AFM imaging

Science.gov (United States)

Bakucz, Peter; Yacoot, Andrew; Dziomba, Thorsten; Koenders, Ludger; Krüger-Sehm, Rolf

2008-06-01

The abrasion (wear) of tips used in scanning force microscopy (SFM) directly influences SFM image quality and is therefore of great relevance to quantitative SFM measurements. The increasing implementation of automated SFM measurement schemes has become a strong driving force for increasing efforts towards the prediction of tip wear, as it needs to be ensured that the probe is exchanged before a level of tip wear is reached that adversely affects the measurement quality. In this paper, we describe the identification of tip abrasion in a system of SFM measurements. We attempt to model the tip-abrasion process as a concatenation of a mapping from the measured AFM data to a regression vector and a nonlinear mapping from the regressor space to the output space. The mapping is formed as a basis function expansion. Feedforward neural networks are used to approximate this mapping. The one-hidden layer network gave a good quality of fit for the training and test sets for the tip-abrasion system. We illustrate our method with AFM measurements of both fine periodic structures and randomly oriented sharp features and compare our neural network results with those obtained using other methods.

AFM image of an entire polygene chromosome

International Nuclear Information System (INIS)

Li Minqian; Takeuchi; Ikai, A.

1994-01-01

The author present AFM images of an entire polygene chromosome of Drosophila for the first time. Comparing with conventional optical microscope, the AFM image of the polygene chromosomes provides much higher resolution and 3-D measurement capability which will lead to finer scale gene mapping and identification

MetaRep, an extended CMAS 3D program to visualize mafic (CMAS, ACF-S, ACF-N) and pelitic (AFM-K, AFM-S, AKF-S) projections

Science.gov (United States)

France, Lydéric; Nicollet, Christian

2010-06-01

MetaRep is a program based on our earlier program CMAS 3D. It is developed in MATLAB ® script. MetaRep objectives are to visualize and project major element compositions of mafic and pelitic rocks and their minerals in the pseudo-quaternary projections of the ACF-S, ACF-N, CMAS, AFM-K, AFM-S and AKF-S systems. These six systems are commonly used to describe metamorphic mineral assemblages and magmatic evolutions. Each system, made of four apices, can be represented in a tetrahedron that can be visualized in three dimensions with MetaRep; the four tetrahedron apices represent oxides or combination of oxides that define the composition of the projected rock or mineral. The three-dimensional representation allows one to obtain a better understanding of the topology of the relationships between the rocks and minerals and relations. From these systems, MetaRep can also project data in ternary plots (for example, the ACF, AFM and AKF ternary projections can be generated). A functional interface makes it easy to use and does not require any knowledge of MATLAB ® programming. To facilitate the use, MetaRep loads, from the main interface, data compiled in a Microsoft Excel ™ spreadsheet. Although useful for scientific research, the program is also a powerful tool for teaching. We propose an application example that, by using two combined systems (ACF-S and ACF-N), provides strong confirmation in the petrological interpretation.

Atomic Force Microscopy for Soil Analysis

Science.gov (United States)

gazze, andrea; doerr, stefan; dudley, ed; hallin, ingrid; matthews, peter; quinn, gerry; van keulen, geertje; francis, lewis

2016-04-01

Atomic Force Microscopy (AFM) is a high-resolution surface-sensitive technique, which provides 3-dimensional topographical information and material properties of both stiff and soft samples in their natural environments. Traditionally AFM has been applied to samples with low roughness: hence its use for soil analysis has been very limited so far. Here we report the optimization settings required for a standardization of high-resolution and artefact-free analysis of natural soil with AFM: soil immobilization, AFM probe selection, artefact recognition and minimization. Beyond topography, AFM can be used in a spectroscopic mode to evaluate nanomechanical properties, such as soil viscosity, stiffness, and deformation. In this regards, Bruker PeakForce-Quantitative NanoMechanical (QNM) AFM provides a fast and convenient way to extract physical properties from AFM force curves in real-time to obtain soil nanomechanical properties. Here we show for the first time the ability of AFM to describe the topography of natural soil at nanometre resolution, with observation of micro-components, such as clays, and of nano-structures, possibly of biotic origin, the visualization of which would prove difficult with other instrumentations. Finally, nanomechanical profiling has been applied to different wettability states in soil and the respective physical patterns are discussed.

AFM ve farmaceutické technologii 3.

OpenAIRE

Ščuryová, Veronika

2015-01-01

Charles University in Prague Faculty of Pharmacy in Hradec Králové Department of Pharmaceutical Technology Student: Veronika Ščuryová Supervisor: doc. RNDr. Pavel Doležal, CSc. Title of thesis: AFM in Pharmaceutical Technology 3 The theoretical part deals first with the construction of AFM microscope, the principle of the method, determining the surface topography and regimes which can be used. Described therein are distinct advantages over previous traditional methods but also its pitfalls. ...

Quantitative measurements of shear displacement using atomic force microscopy

International Nuclear Information System (INIS)

Wang, Wenbo; Wu, Weida; Sun, Ying; Zhao, Yonggang

2016-01-01

We report a method to quantitatively measure local shear deformation with high sensitivity using atomic force microscopy. The key point is to simultaneously detect both torsional and buckling motions of atomic force microscopy (AFM) cantilevers induced by the lateral piezoelectric response of the sample. This requires the quantitative calibration of torsional and buckling response of AFM. This method is validated by measuring the angular dependence of the in-plane piezoelectric response of a piece of piezoelectric α-quartz. The accurate determination of the amplitude and orientation of the in-plane piezoelectric response, without rotation, would greatly enhance the efficiency of lateral piezoelectric force microscopy.

High-speed AFM of human chromosomes in liquid

Energy Technology Data Exchange (ETDEWEB)

Picco, L M; Dunton, P G; Ulcinas, A; Engledew, D J; Miles, M J [H H Wills Physics Laboratory and IRC in Nanotechnology, University of Bristol, Tyndall Avenue, Bristol BS8 1TL (United Kingdom); Hoshi, O; Ushiki, T [Division of Microscopic Anatomy and Bio-Imaging, Department of Cellular Function, Niigata University Graduate School of Medical and Dental Sciences, Asahimachi-Dori 1, Niigata, 951-8150 (Japan)], E-mail: m.j.miles@bristol.ac.uk

2008-09-24

Further developments of the previously reported high-speed contact-mode AFM are described. The technique is applied to the imaging of human chromosomes at video rate both in air and in water. These are the largest structures to have been imaged with high-speed AFM and the first imaging in liquid to be reported. A possible mechanism that allows such high-speed contact-mode imaging without significant damage to the sample is discussed in the context of the velocity dependence of the measured lateral force on the AFM tip.

Quantitative assessment of contact and non-contact lateral force calibration methods for atomic force microscopy

Energy Technology Data Exchange (ETDEWEB)

Tran Khac, Bien Cuong; Chung, Koo-Hyun, E-mail: khchung@ulsan.ac.kr

2016-02-15

Atomic Force Microscopy (AFM) has been widely used for measuring friction force at the nano-scale. However, one of the key challenges faced by AFM researchers is to calibrate an AFM system to interpret a lateral force signal as a quantifiable force. In this study, five rectangular cantilevers were used to quantitatively compare three different lateral force calibration methods to demonstrate the legitimacy and to establish confidence in the quantitative integrity of the proposed methods. The Flat-Wedge method is based on a variation of the lateral output on a surface with flat and changing slopes, the Multi-Load Pivot method is based on taking pivot measurements at several locations along the cantilever length, and the Lateral AFM Thermal-Sader method is based on determining the optical lever sensitivity from the thermal noise spectrum of the first torsional mode with a known torsional spring constant from the Sader method. The results of the calibration using the Flat-Wedge and Multi-Load Pivot methods were found to be consistent within experimental uncertainties, and the experimental uncertainties of the two methods were found to be less than 15%. However, the lateral force sensitivity determined by the Lateral AFM Thermal-Sader method was found to be 8–29% smaller than those obtained from the other two methods. This discrepancy decreased to 3–19% when the torsional mode correction factor for an ideal cantilever was used, which suggests that the torsional mode correction should be taken into account to establish confidence in Lateral AFM Thermal-Sader method. - Highlights: • Quantitative assessment of three lateral force calibration methods for AFM. • Advantages and disadvantages of three different lateral force calibration method. • Implementation of Multi-Load Pivot method as non-contact calibration technique. • The torsional mode correction for Lateral AFM Thermal-Sader method.

Quantitative assessment of contact and non-contact lateral force calibration methods for atomic force microscopy

International Nuclear Information System (INIS)

Tran Khac, Bien Cuong; Chung, Koo-Hyun

2016-01-01

Atomic Force Microscopy (AFM) has been widely used for measuring friction force at the nano-scale. However, one of the key challenges faced by AFM researchers is to calibrate an AFM system to interpret a lateral force signal as a quantifiable force. In this study, five rectangular cantilevers were used to quantitatively compare three different lateral force calibration methods to demonstrate the legitimacy and to establish confidence in the quantitative integrity of the proposed methods. The Flat-Wedge method is based on a variation of the lateral output on a surface with flat and changing slopes, the Multi-Load Pivot method is based on taking pivot measurements at several locations along the cantilever length, and the Lateral AFM Thermal-Sader method is based on determining the optical lever sensitivity from the thermal noise spectrum of the first torsional mode with a known torsional spring constant from the Sader method. The results of the calibration using the Flat-Wedge and Multi-Load Pivot methods were found to be consistent within experimental uncertainties, and the experimental uncertainties of the two methods were found to be less than 15%. However, the lateral force sensitivity determined by the Lateral AFM Thermal-Sader method was found to be 8–29% smaller than those obtained from the other two methods. This discrepancy decreased to 3–19% when the torsional mode correction factor for an ideal cantilever was used, which suggests that the torsional mode correction should be taken into account to establish confidence in Lateral AFM Thermal-Sader method. - Highlights: • Quantitative assessment of three lateral force calibration methods for AFM. • Advantages and disadvantages of three different lateral force calibration method. • Implementation of Multi-Load Pivot method as non-contact calibration technique. • The torsional mode correction for Lateral AFM Thermal-Sader method.

Quantitative investment analysis

CERN Document Server

DeFusco, Richard

2007-01-01

In the "Second Edition" of "Quantitative Investment Analysis," financial experts Richard DeFusco, Dennis McLeavey, Jerald Pinto, and David Runkle outline the tools and techniques needed to understand and apply quantitative methods to today's investment process.

Hydration states of AFm cement phases

Energy Technology Data Exchange (ETDEWEB)

Baquerizo, Luis G., E-mail: luis.baquerizoibarra@holcim.com [Innovation, Holcim Technology Ltd., CH-5113 Holderbank (Switzerland); Matschei, Thomas [Innovation, Holcim Technology Ltd., CH-5113 Holderbank (Switzerland); Scrivener, Karen L. [Laboratory of Construction Materials, Ecole Polytechnique Fédérale de Lausanne, CH-1015 Lausanne (Switzerland); Saeidpour, Mahsa; Wadsö, Lars [Building Materials, Lund University, Box 124, 221 000 Lund (Sweden)

2015-07-15

The AFm phase, one of the main products formed during the hydration of Portland and calcium aluminate cement based systems, belongs to the layered double hydrate (LDH) family having positively charged layers and water plus charge-balancing anions in the interlayer. It is known that these phases present different hydration states (i.e. varying water content) depending on the relative humidity (RH), temperature and anion type, which might be linked to volume changes (swelling and shrinkage). Unfortunately the stability conditions of these phases are insufficiently reported. This paper presents novel experimental results on the different hydration states of the most important AFm phases: monocarboaluminate, hemicarboaluminate, strätlingite, hydroxy-AFm and monosulfoaluminate, and the thermodynamic properties associated with changes in their water content during absorption/desorption. This data opens the possibility to model the response of cementitious systems during drying and wetting and to engineer systems more resistant to harsh external conditions.

Tip-Enhanced Raman Voltammetry: Coverage Dependence and Quantitative Modeling.

Science.gov (United States)

Mattei, Michael; Kang, Gyeongwon; Goubert, Guillaume; Chulhai, Dhabih V; Schatz, George C; Jensen, Lasse; Van Duyne, Richard P

2017-01-11

Electrochemical atomic force microscopy tip-enhanced Raman spectroscopy (EC-AFM-TERS) was employed for the first time to observe nanoscale spatial variations in the formal potential, E 0' , of a surface-bound redox couple. TERS cyclic voltammograms (TERS CVs) of single Nile Blue (NB) molecules were acquired at different locations spaced 5-10 nm apart on an indium tin oxide (ITO) electrode. Analysis of TERS CVs at different coverages was used to verify the observation of single-molecule electrochemistry. The resulting TERS CVs were fit to the Laviron model for surface-bound electroactive species to quantitatively extract the formal potential E 0' at each spatial location. Histograms of single-molecule E 0' at each coverage indicate that the electrochemical behavior of the cationic oxidized species is less sensitive to local environment than the neutral reduced species. This information is not accessible using purely electrochemical methods or ensemble spectroelectrochemical measurements. We anticipate that quantitative modeling and measurement of site-specific electrochemistry with EC-AFM-TERS will have a profound impact on our understanding of the role of nanoscale electrode heterogeneity in applications such as electrocatalysis, biological electron transfer, and energy production and storage.

Scanning transmission ion microscopy mass measurements for quantitative trace element analysis within biological samples and validation using atomic force microscopy thickness measurements

Energy Technology Data Exchange (ETDEWEB)

Deves, Guillaume [Laboratoire de chimie nucleaire analytique et bioenvironnementale, UMR 5084, CNRS-Universite de Bordeaux 1, BP 120 Chemin du solarium, F33175 Gradignan cedex (France)]. E-mail: deves@cenbg.in2p3.fr; Cohen-Bouhacina, Touria [Centre de Physique Moleculaire Optique et Hertzienne, Universite de Bordeaux 1, 351, cours de la Liberation, F33405 Talence cedex (France); Ortega, Richard [Laboratoire de chimie nucleaire analytique et bioenvironnementale, UMR 5084, CNRS-Universite de Bordeaux 1, BP 120 Chemin du solarium, F33175 Gradignan cedex (France)

2004-10-08

We used the nuclear microprobe techniques, micro-PIXE (particle-induced X-ray emission), micro-RBS (Rutherford backscattering spectrometry) and scanning transmission ion microscopy (STIM) in order to perform the characterization of trace element content and spatial distribution within biological samples (dehydrated cultured cells, tissues). The normalization of PIXE results was usually expressed in terms of sample dry mass as determined by micro-RBS recorded simultaneously to micro-PIXE. However, the main limit of RBS mass measurement is the sample mass loss occurring during irradiation and which could be up to 30% of the initial sample mass. We present here a new methodology for PIXE normalization and quantitative analysis of trace element within biological samples based on dry mass measurement performed by mean of STIM. The validation of STIM cell mass measurements was obtained in comparison with AFM sample thickness measurements. Results indicated the reliability of STIM mass measurement performed on biological samples and suggested that STIM should be performed for PIXE normalization. Further information deriving from direct confrontation of AFM and STIM analysis could as well be obtained, like in situ measurements of cell specific gravity within cells compartment (nucleolus and cytoplasm)

Simultaneous AFM and fluorescence imaging: A method for aligning an AFM-tip with an excitation beam using a 2D galvanometer

Science.gov (United States)

Moores, A. N.; Cadby, A. J.

2018-02-01

Correlative fluorescence and atomic force microscopy (AFM) imaging is a highly attractive technique for use in biological imaging, enabling force and mechanical measurements of particular structures whose locations are known due to the specificity of fluorescence imaging. The ability to perform these two measurements simultaneously (rather than consecutively with post-processing correlation) is highly valuable because it would allow the mechanical properties of a structure to be tracked over time as changes in the sample occur. We present an instrument which allows simultaneous AFM and fluorescence imaging by aligning an incident fluorescence excitation beam with an AFM-tip. Alignment was performed by calibrating a 2D galvanometer present in the excitation beam path and using it to reposition the incident beam. Two programs were developed (one manual and one automated) which correlate sample features between the AFM and fluorescence images, calculating the distance required to translate the incident beam towards the AFM-tip. Using this method, we were able to obtain beam-tip alignment (and therefore field-of-view alignment) from an offset of >15 μm to within one micron in two iterations of the program. With the program running alongside data acquisition for real-time feedback between AFM and optical images, this offset was maintained over a time period of several hours. Not only does this eliminate the need to image large areas with both techniques to ensure that fields-of-view overlap, but it also raises the possibility of using this instrument for tip-enhanced fluorescence applications, a technique in which super-resolution images have previously been achieved.

Amyloid and membrane complexity: The toxic interplay revealed by AFM.

Science.gov (United States)

Canale, Claudio; Oropesa-Nuñez, Reinier; Diaspro, Alberto; Dante, Silvia

2018-01-01

Lipid membranes play a fundamental role in the pathological development of protein misfolding diseases. Several pieces of evidence suggest that the lipid membrane could act as a catalytic surface for protein aggregation. Furthermore, a leading theory indicates the interaction between the cell membrane and misfolded oligomer species as the responsible for cytotoxicity, hence, for neurodegeneration in disorders such as Alzheimer's and Parkinson's disease. The definition of the mechanisms that drive the interaction between pathological protein aggregates and plasma membrane is fundamental for the development of effective therapies for a large class of diseases. Atomic force microscopy (AFM) has been employed to study how amyloid aggregates affect the cell physiological properties. Considerable efforts were spent to characterize the interaction with model systems, i.e., planar supported lipid bilayers, but some works also addressed the problem directly on living cells. Here, an overview of the main works involving the use of the AFM on both model system and living cells will be provided. Different kind of approaches will be presented, as well as the main results derived from the AFM analysis. Copyright © 2017 Elsevier Ltd. All rights reserved.

An AFM-SIMS Nano Tomography Acquisition System

Science.gov (United States)

Swinford, Richard William

An instrument, adding the capability to measure 3D volumetric chemical composition, has been constructed by me as a member of the Sanchez Nano Laboratory. The laboratory's in situ atomic force microscope (AFM) and secondary ion mass spectrometry systems (SIMS) are functional and integrated as one instrument. The SIMS utilizes a Ga focused ion beam (FIB) combined with a quadrupole mass analyzer. The AFM is comprised of a 6-axis stage, three coarse axes and three fine. The coarse stage is used for placing the AFM tip anywhere inside a (13x13x5 mm3) (xyz) volume. Thus the tip can be moved in and out of the FIB processing region with ease. The planned range for the Z-axis piezo was 60 microm, but was reduced after it was damaged from arc events. The repaired Z-axis piezo is now operated at a smaller nominal range of 18 microm (16.7 microm after pre-loading), still quite respectable for an AFM. The noise floor of the AFM is approximately 0.4 nm Rq. The voxel size for the combined instrument is targeted at 50 nm or larger. Thus 0.4 nm of xyz uncertainty is acceptable. The instrument has been used for analyzing samples using FIB beam currents of 250 pA and 5.75 nA. Coarse tip approaches can take a long time so an abbreviated technique is employed. Because of the relatively long thro of the Z piezo, the tip can be disengaged by deactivating the servo PID. Once disengaged, it can be moved laterally out of the way of the FIB-SIMS using the coarse stage. This instrument has been used to acquire volumetric data on AlTiC using AFM tip diameters of 18.9 nm and 30.6 nm. Acquisition times are very long, requiring multiple days to acquire a 50-image stack. New features to be added include auto stigmation, auto beam shift, more software automation, etc. Longer term upgrades to include a new lower voltage Z-piezo with strain-gauge feedback and a new design to extend the life for the coarse XY nano-positioners. This AFM-SIMS instrument, as constructed, has proven to be a great proof

Quantitative measurements of electromechanical response with a combined optical beam and interferometric atomic force microscope

Energy Technology Data Exchange (ETDEWEB)

Labuda, Aleksander; Proksch, Roger [Asylum Research an Oxford Instruments Company, Santa Barbara, California 93117 (United States)

2015-06-22

An ongoing challenge in atomic force microscope (AFM) experiments is the quantitative measurement of cantilever motion. The vast majority of AFMs use the optical beam deflection (OBD) method to infer the deflection of the cantilever. The OBD method is easy to implement, has impressive noise performance, and tends to be mechanically robust. However, it represents an indirect measurement of the cantilever displacement, since it is fundamentally an angular rather than a displacement measurement. Here, we demonstrate a metrological AFM that combines an OBD sensor with a laser Doppler vibrometer (LDV) to enable accurate measurements of the cantilever velocity and displacement. The OBD/LDV AFM allows a host of quantitative measurements to be performed, including in-situ measurements of cantilever oscillation modes in piezoresponse force microscopy. As an example application, we demonstrate how this instrument can be used for accurate quantification of piezoelectric sensitivity—a longstanding goal in the electromechanical community.

Application of focused ion beam for the fabrication of AFM probes

Science.gov (United States)

Kolomiytsev, A. S.; Lisitsyn, S. A.; Smirnov, V. A.; Fedotov, A. A.; Varzarev, Yu N.

2017-10-01

The results of an experimental study of the probe tips fabrication for critical-dimension atomic force microscopy (CD-AFM) using the focused ion beam (FIB) induced deposition are presented. Methods of the FIB-induced deposition of tungsten and carbon onto the tip of an AFM probe are studied. Based on the results obtained in the study, probes for the CD-AFM technique with a tip height about 1 μm and radius of 20 nm were created. The formation of CD-AFM probes by FIB-induced deposition allows creating a high efficiency tool for nanotechnology and nanodiagnostics. The use of modified cantilevers allows minimizing the artefacts of AFM images and increasing the accuracy of the relief measurement. The obtained results can be used for fabrication of AFM probes for express monitoring of the technological process in the manufacturing of the elements for micro- and nanoelectronics.

Analysis of aflatoxin M1 in milk and yogurt and AFM1 reduction by lactic acid bacteria used in Lebanese industry

International Nuclear Information System (INIS)

El Khoury, A.; Yaghi, J.; Atoui, A.

2011-01-01

In this study a screening survey was undertaken to determine the presence and levels of aflatoxin M1 (AFM1) in locally produced dairy products. For this purpose, a total of 138 dairy samples (milk and yogurt) were analyzed to quantify AFM1 levels in these products. Results obtained showed that AFM1 was found in 40.62% and 32.81% of milk and yogurt samples respectively. The range of contamination levels varied between lower and higher than European regulation limit. Lactic acid bacteria (Lactobacillus bulgaricus and Streptococcus thermophilus) used in the Lebanese traditional industry were screened for their ability to reduce the level of AFM1. Due to the lack in data on the natural occurrence of AFM1 in Lebanese dairy products, the aim of this work was to report some information and to state these products according to EC regulations. (author)

Fracture Mechanics Testing of Titanium 6AL-4V in AF-M315E

Science.gov (United States)

Sampson, J. W.; Martinez, J.; McLean, C.

2016-01-01

The Green Propellant Infusion Mission (GPIM) will demonstrate the performance of AF-M315E monopropellant on orbit. Flight certification requires a safe-life analysis of the titanium alloy fuel tank to ensure inherent processing flaws will not cause failure during the design life of the tank. Material property inputs for this analysis require testing to determine the stress intensity factor for environment-assisted cracking (KEAC) of Ti 6Al-4V in combination with the AF-M315E monopropellant. Testing of single-edge notched, or SE(B), specimens representing the bulk tank membrane and weld material were performed in accordance with ASTM E1681. Specimens with fatigue pre-cracks were loaded into test fixtures so that the crack tips were exposed to AF-M315E at 50 C for a duration of 1,000 hours. Specimens that did not fail during exposure were opened to inspect the crack surfaces for evidence of crack growth. The threshold stress intensity value, KEAC, is the highest applied stress intensity that produced neither a failure of the specimen during the exposure nor showed evidence of crack growth. The threshold stress intensity factor for environment-assisted cracking of the Ti 6Al-4V forged tank material was found to be at least 22 ksivin and at least 31 ksivin for the weld material when exposed to AF-M315E monopropellant.

Improving the speed of AFM by mechatronic design and modern control methods

International Nuclear Information System (INIS)

Schitter, Georg

2009-01-01

In Atomic Force Microscopy (AFM) high-performance and high-precision control of the AFM scanner and of the imaging forces is crucial. Particularly at high imaging speeds the dynamic behaviour of the scanner may cause imaging artifacts and limit the maximum imaging rate. This contribution discusses and presents recent improvements in AFM instrumentation for faster imaging by means of mechatronic design and utilizing modern control engineering methods. Combining these improvements enables AFM imaging at more than two orders of magnitudes faster than conventional AFMs. (orig.)

AFM imaging and analysis of local mechanical properties for detection of surface pattern of functional groups

Energy Technology Data Exchange (ETDEWEB)

Knotek, Petr, E-mail: petr.knotek@upce.cz [University of Pardubice, Faculty of Chemical Technology, Joint Laboratory of Solid State Chemistry of IMC ASCR and University of Pardubice, Studentska 573, 532 10 Pardubice (Czech Republic); Chanova, Eliska; Rypacek, Frantisek [Institute of Macromolecular Chemistry, Academy of Sciences of the Czech Republic, Heyrovskeho sq. 2, 162 06 Prague (Czech Republic)

2013-05-01

In this work we evaluate the applicability of different atomic force microscopy (AFM) modes, such as Phase Shift Imaging, Atomic Force Acoustic Microscopy (AFAM) and Force Spectroscopy, for mapping of the distribution pattern of low-molecular-weight biomimetic groups on polymer biomaterial surfaces. Patterns with either random or clustered spatial distribution of bioactive peptide group derived from fibronectin were prepared by surface deposition of functional block copolymer nano-colloids and grafted with RGDS peptide containing the sequence of amino acids arginine–glycine–aspartic acid–serine (conventionally labeled as RGDS) and carrying biotin as a tag. The biotin-tagged peptides were labeled with 40 nm streptavidin-modified Au nanospheres. The peptide molecules were localized through the detection of bound Au nanospheres by AFM, and thus, the surface distribution of peptides was revealed. AFM techniques capable of monitoring local mechanical properties of the surface were proved to be the most efficient for identification of Au nano-markers. The efficiency was successfully demonstrated on two different patterns, i.e. random and clustered distribution of RGDS peptides on structured surface of the polymer biomaterial. Highlights: ► Bioactive peptides for cell adhesion on PLA-b-PEO biomimetic surface were visualized. ► The biotin-tagged RGDS peptides were labeled with streptavidin-Au nanospheres. ► The RGDS pattern was detected using different atomic force microscopy (AFM) modes. ► Phase Shift Image was proved to be suitable method for studying peptide distribution.

Changes in surface characteristics of two different resin composites after 1 year water storage: An SEM and AFM study.

Science.gov (United States)

Tekçe, Neslihan; Pala, Kansad; Demirci, Mustafa; Tuncer, Safa

2016-11-01

To evaluate changes in surface characteristics of two different resin composites after 1 year of water storage using a profilometer, Vickers hardness, scanning electron microscopy (SEM), and atomic force microscopy (AFM). A total of 46 composite disk specimens (10 mm in diameter and 2 mm thick) were fabricated using Clearfil Majesty Esthetic and Clearfil Majesty Posterior (Kuraray Medical Co, Tokyo, Japan). Ten specimens from each composite were used for surface roughness and microhardness tests (n = 10). For each composite, scanning electron microscope (SEM, n = 2) and atomic force microscope (AFM, n = 1) images were obtained after 24 h and 1 year of water storage. The data were analyzed using two-way analysis of variance and a post-hoc Bonferroni test. Microhardness values of Clearfil Majesty Esthetic decreased significantly (78.15-63.74, p = 0.015) and surface roughness values did not change after 1 year of water storage (0.36-0.39, p = 0.464). Clearfil Majesty Posterior microhardness values were quite stable (138.74-137.25, p = 0.784), and surface roughness values increased significantly (0.39-0.48, p = 0.028) over 1 year. One year of water storage caused microhardness values for Clearfil Majesty Esthetic to decrease and the surface roughness of Clearfil Majesty Posterior increased. AFM and SEM images demonstrated surface detoration of the materials after 1 year and ensured similar results with the quantitative test methods. SCANNING 38:694-700, 2016. © 2016 Wiley Periodicals, Inc. © Wiley Periodicals, Inc.

Vacuolar structures can be identified by AFM elasticity mapping

International Nuclear Information System (INIS)

Riethmueller, Christoph; Schaeffer, Tilman E.; Kienberger, Ferry; Stracke, Werner; Oberleithner, Hans

2007-01-01

Fluid-filled organelles like vesicles, endosomes and pinosomes are inevitable parts of cellular signalling and transport. Endothelial cells, building a barrier between blood and tissue, can form vacuolar organelles. These structures are implicated in upregulated fluid transport across the endothelium under inflammatory conditions. Vacuolar organelles have been described by transmission electron microscopy so far. Here, we present a method that images and mechanically characterizes intracellular structures in whole cells by atomic force microscopy (AFM). After crosslinking the cellular proteins with the fixative glutaraldehyde, plasma membrane depressions become observable, which are scattered around the cell nucleus. Nanomechanical analysis identifies them as spots of reduced stiffness. Scanning electron microscopy confirms their pit-like appearance. In addition, fluorescence microscopy detects an analogous pattern of protein-poor spots, thereby confirming mechanical rigidity to arise from crosslinked proteins. This AFM application opens up a mechanical dimension for the investigation of intracellular organelles

Quantitative analysis of dynamic adhesion properties in human hepatocellular carcinoma cells with fullerenol.

Science.gov (United States)

Liu, Yang; Wang, Zuobin; Wang, Xinyue; Huang, Yanhong

2015-12-01

In this study, the effect of fullerenol (C60(OH)24) on the cellular dynamic biomechanical behaviors of living human hepatocellular carcinoma (SMCC-7721) cancer cells were investigated by atomic force microscope (AFM) nanoindentation. As an important biomarker of cellular information, the cell adhesion is essential to maintain proper functioning as well as links with the pathogenesis and canceration. Nonetheless, it is challenging to properly evaluate the complex adhesion properties as all the biomechanical parameters interfere with each other. To investigate the dynamic adhesion changes, especially in the case of the fullerenol treatment, the detachment force and work, adhesion events, and membrane tether properties were measured and analyzed systematically with the proposed quantitative method. The statistical analyses suggest that, under the same operating parameters of AFM, the dependence of adhesion energy on the tip-cell contact area is weakened after the fullerenol treatment and the probability of adhesion decreases significantly from 30.6% to 4.2%. In addition, the disruption of the cytoskeleton resulted in a 34% decrease of the average membrane tether force and a 21% increase of the average tether length. Benefiting from the quantitative method, this work contributes to revealing the effects of fullerenol on the cellular biomechanical properties of the living SMCC-7721 cells in a precise and rigorous way and additionally is further instructive to interpret the interaction mechanism of other potential nanomedicines with living cells. Copyright © 2015 Elsevier Ltd. All rights reserved.

Analysis of effect of nanoporous alumina substrate coated with polypyrrole nanowire on cell morphology based on AFM topography.

Science.gov (United States)

El-Said, Waleed Ahmed; Yea, Cheol-Heon; Jung, Mi; Kim, Hyuncheol; Choi, Jeong-Woo

2010-05-01

In this study, in situ electrochemical synthesis of polypyrrole nanowires with nanoporous alumina template was described. The formation of highly ordered porous alumina substrate was demonstrated with Atomic Force Microscopy (AFM) and Scanning Electron Microscopy (SEM). In addition, Fourier transform infrared analysis confirmed that polypyrrole (PP) nanowires were synthesized by direct electrochemical oxidation of pyrrole. HeLa cancer cells and HMCF normal cells were immobilized on the polypyrrole nanowires/nanoporous alumina substrates to determine the effects of the substrate on the cell morphology, adhesion and proliferation as well as the biocompatibility of the substrate. Cell adhesion and proliferation were characterized using a standard MTT assay. The effects of the polypyrrole nanowires/nanoporous alumina substrate on the cell morphology were studied by AFM. The nanoporous alumina coated with polypyrrole nanowires was found to exhibit better cell adhesion and proliferation than polystyrene petridish, aluminum foil, 1st anodized and uncoated 2nd anodized alumina substrate. This study showed the potential of the polypyrrole nanowires/nanoporous alumina substrate as biocompatibility electroactive polymer substrate for both healthy and cancer cell cultures applications.

Qualitative and Quantitative Analysis of ROS-Mediated Oridonin-Induced Oesophageal Cancer KYSE-150 Cell Apoptosis by Atomic Force Microscopy.

Directory of Open Access Journals (Sweden)

Jiang Pi

Full Text Available High levels of intracellular reactive oxygen species (ROS in cells is recognized as one of the major causes of cancer cell apoptosis and has been developed into a promising therapeutic strategy for cancer therapy. However, whether apoptosis associated biophysical properties of cancer cells are related to intracellular ROS functions is still unclear. Here, for the first time, we determined the changes of biophysical properties associated with the ROS-mediated oesophageal cancer KYSE-150 cell apoptosis using high resolution atomic force microscopy (AFM. Oridonin was proved to induce ROS-mediated KYSE-150 cell apoptosis in a dose dependent manner, which could be reversed by N-acetylcysteine (NAC pretreatment. Based on AFM imaging, the morphological damage and ultrastructural changes of KYSE-150 cells were found to be closely associated with ROS-mediated oridonin-induced KYSE-150 cell apoptosis. The changes of cell stiffness determined by AFM force measurement also demonstrated ROS-dependent changes in oridonin induced KYSE-150 cell apoptosis. Our findings not only provided new insights into the anticancer effects of oridonin, but also highlighted the use of AFM as a qualitative and quantitative nanotool to detect ROS-mediated cancer cell apoptosis based on cell biophysical properties, providing novel information of the roles of ROS in cancer cell apoptosis at nanoscale.

Automated image analysis of atomic force microscopy images of rotavirus particles

International Nuclear Information System (INIS)

Venkataraman, S.; Allison, D.P.; Qi, H.; Morrell-Falvey, J.L.; Kallewaard, N.L.; Crowe, J.E.; Doktycz, M.J.

2006-01-01

A variety of biological samples can be imaged by the atomic force microscope (AFM) under environments that range from vacuum to ambient to liquid. Generally imaging is pursued to evaluate structural features of the sample or perhaps identify some structural changes in the sample that are induced by the investigator. In many cases, AFM images of sample features and induced structural changes are interpreted in general qualitative terms such as markedly smaller or larger, rougher, highly irregular, or smooth. Various manual tools can be used to analyze images and extract more quantitative data, but this is usually a cumbersome process. To facilitate quantitative AFM imaging, automated image analysis routines are being developed. Viral particles imaged in water were used as a test case to develop an algorithm that automatically extracts average dimensional information from a large set of individual particles. The extracted information allows statistical analyses of the dimensional characteristics of the particles and facilitates interpretation related to the binding of the particles to the surface. This algorithm is being extended for analysis of other biological samples and physical objects that are imaged by AFM

Automated image analysis of atomic force microscopy images of rotavirus particles

Energy Technology Data Exchange (ETDEWEB)

Venkataraman, S. [Life Sciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831 (United States); Department of Electrical and Computer Engineering, University of Tennessee, Knoxville, TN 37996 (United States); Allison, D.P. [Life Sciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831 (United States); Department of Biochemistry, Cellular, and Molecular Biology, University of Tennessee, Knoxville, TN 37996 (United States); Molecular Imaging Inc. Tempe, AZ, 85282 (United States); Qi, H. [Department of Electrical and Computer Engineering, University of Tennessee, Knoxville, TN 37996 (United States); Morrell-Falvey, J.L. [Life Sciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831 (United States); Kallewaard, N.L. [Vanderbilt University Medical Center, Nashville, TN 37232-2905 (United States); Crowe, J.E. [Vanderbilt University Medical Center, Nashville, TN 37232-2905 (United States); Doktycz, M.J. [Life Sciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831 (United States)]. E-mail: doktyczmj@ornl.gov

2006-06-15

A variety of biological samples can be imaged by the atomic force microscope (AFM) under environments that range from vacuum to ambient to liquid. Generally imaging is pursued to evaluate structural features of the sample or perhaps identify some structural changes in the sample that are induced by the investigator. In many cases, AFM images of sample features and induced structural changes are interpreted in general qualitative terms such as markedly smaller or larger, rougher, highly irregular, or smooth. Various manual tools can be used to analyze images and extract more quantitative data, but this is usually a cumbersome process. To facilitate quantitative AFM imaging, automated image analysis routines are being developed. Viral particles imaged in water were used as a test case to develop an algorithm that automatically extracts average dimensional information from a large set of individual particles. The extracted information allows statistical analyses of the dimensional characteristics of the particles and facilitates interpretation related to the binding of the particles to the surface. This algorithm is being extended for analysis of other biological samples and physical objects that are imaged by AFM.

A comprehensive modeling and vibration analysis of AFM microcantilevers subjected to nonlinear tip-sample interaction forces

International Nuclear Information System (INIS)

Eslami, Sohrab; Jalili, Nader

2012-01-01

Precise and accurate representation of an Atomic Force Microscopy (AFM) system is essential in studying the effects of boundary interaction forces present between the probe's tip and the sample. In this paper, a comprehensive analytical model for the AFM system utilizing a distributed-parameters based approach is proposed. More specifically, we consider two important attributes of these systems; namely the rotary inertia and shear deformation when compared with the Euler–Bernoulli beam theory. Moreover, a comprehensive nonlinear interaction force is assumed between probe's and sample in order to reveal the response of the system more realistically. This nanoscale interaction force is based on a general form consisting of both attractive and repulsive components as well as a function of the tip-sample distance and the microcantilever's base and sample oscillations. Mechanical properties of the sample could interact with the nanomechanical coupling field between the probe' tip and sample and be implemented in studying the composition information of the sample and the ultra-small features inside it. Therefore, by modulating the dynamics of the AFM system such as the driving amplitude of the microcantilever the procedure for the subsurface imaging is described. The presented approach here could be implemented for designing the AFM probes by examining the tip-sample interaction forces dominant by the van der Waals forces. Several numerical case studies are presented and the force–distance diagram reveals that the proposed nonlinear nanomechanical force along with the distributed-parameters model for the microcantilever is able to fulfill the mechanics of the Lennard–Jones potential. -- Highlights: ► We present a comprehensive distributed-parameters model for AFM microcantilever. ► Assuming a nonlinear and implicit interaction force between tip and sample. ► Timoshenko beam is compared with the Euler–Bernoulli having the same force model. ► Frequency

Analysis of DNA interactions using single-molecule force spectroscopy.

Science.gov (United States)

Ritzefeld, Markus; Walhorn, Volker; Anselmetti, Dario; Sewald, Norbert

2013-06-01

Protein-DNA interactions are involved in many biochemical pathways and determine the fate of the corresponding cell. Qualitative and quantitative investigations on these recognition and binding processes are of key importance for an improved understanding of biochemical processes and also for systems biology. This review article focusses on atomic force microscopy (AFM)-based single-molecule force spectroscopy and its application to the quantification of forces and binding mechanisms that lead to the formation of protein-DNA complexes. AFM and dynamic force spectroscopy are exciting tools that allow for quantitative analysis of biomolecular interactions. Besides an overview on the method and the most important immobilization approaches, the physical basics of the data evaluation is described. Recent applications of AFM-based force spectroscopy to investigate DNA intercalation, complexes involving DNA aptamers and peptide- and protein-DNA interactions are given.

Atom-resolved AFM imaging of calcite nanoparticles in water

Energy Technology Data Exchange (ETDEWEB)

Imada, Hirotake; Kimura, Kenjiro [Department of Chemistry, School of Science, Kobe University, Rokko-dai, Nada, Kobe 657-8501 (Japan); Onishi, Hiroshi, E-mail: oni@kobe-u.ac.jp [Department of Chemistry, School of Science, Kobe University, Rokko-dai, Nada, Kobe 657-8501 (Japan)

2013-06-20

Highlights: ► An advanced frequency-modulation AFM (FM-AFM) was applied for imaging particles. ► Atom-resolved topography of nano-sized particles of calcite was observed in water. ► Locally ordered structures were found and assigned to a (104) facet of calcite. ► A promising ability of FM-AFM was demonstrated in imaging nano-sized particles. - Abstract: The atom-resolved topography of calcite nanoparticles was observed in water using a frequency-modulation atomic force microscope. Locally ordered structures were found and assigned to a (104) facet of crystalline calcite.

Atom-resolved AFM imaging of calcite nanoparticles in water

International Nuclear Information System (INIS)

Imada, Hirotake; Kimura, Kenjiro; Onishi, Hiroshi

2013-01-01

Highlights: ► An advanced frequency-modulation AFM (FM-AFM) was applied for imaging particles. ► Atom-resolved topography of nano-sized particles of calcite was observed in water. ► Locally ordered structures were found and assigned to a (104) facet of calcite. ► A promising ability of FM-AFM was demonstrated in imaging nano-sized particles. - Abstract: The atom-resolved topography of calcite nanoparticles was observed in water using a frequency-modulation atomic force microscope. Locally ordered structures were found and assigned to a (104) facet of crystalline calcite

The spin-3/2 Ising model AFM/AFM two-layer lattice with crystal field

International Nuclear Information System (INIS)

Yigit, A.; Albayrak, E.

2010-01-01

The spin-3/2 Ising model is investigated for the case of antiferromagnetic (AFM/AFM) interactions on the two-layer Bethe lattice by using the exact recursion relations in a pairwise approach for given coordination numbers q=3, 4 and 6 when the layers are under the influences of equal external magnetic and equal crystal fields. The ground state (GS) phase diagrams are obtained on the different planes in detail and then the temperature dependent phase diagrams of the system are calculated accordingly. It is observed that the system presents both second- and first-order phase transitions for all q, therefore, tricritical points. It was also found that the system exhibits double-critical end points and isolated points. The model also presents two Neel temperatures, TN, and the existence of which leads to the reentrant behavior.

High-resolution AFM structure of DNA G-wires in aqueous solution.

Science.gov (United States)

Bose, Krishnashish; Lech, Christopher J; Heddi, Brahim; Phan, Anh Tuân

2018-05-17

We investigate the self-assembly of short pieces of the Tetrahymena telomeric DNA sequence d[G 4 T 2 G 4 ] in physiologically relevant aqueous solution using atomic force microscopy (AFM). Wire-like structures (G-wires) of 3.0 nm height with well-defined surface periodic features were observed. Analysis of high-resolution AFM images allowed their classification based on the periodicity of these features. A major species is identified with periodic features of 4.3 nm displaying left-handed ridges or zigzag features on the molecular surface. A minor species shows primarily left-handed periodic features of 2.2 nm. In addition to 4.3 and 2.2 nm ridges, background features with periodicity of 0.9 nm are also observed. Using molecular modeling and simulation, we identify a molecular structure that can explain both the periodicity and handedness of the major G-wire species. Our results demonstrate the potential structural diversity of G-wire formation and provide valuable insight into the structure of higher-order intermolecular G-quadruplexes. Our results also demonstrate how AFM can be combined with simulation to gain insight into biomolecular structure.

Multiple regimes of operation in bimodal AFM: understanding the energy of cantilever eigenmodes

Directory of Open Access Journals (Sweden)

Daniel Kiracofe

2013-06-01

Full Text Available One of the key goals in atomic force microscopy (AFM imaging is to enhance material property contrast with high resolution. Bimodal AFM, where two eigenmodes are simultaneously excited, confers significant advantages over conventional single-frequency tapping mode AFM due to its ability to provide contrast between regions with different material properties under gentle imaging conditions. Bimodal AFM traditionally uses the first two eigenmodes of the AFM cantilever. In this work, the authors explore the use of higher eigenmodes in bimodal AFM (e.g., exciting the first and fourth eigenmodes. It is found that such operation leads to interesting contrast reversals compared to traditional bimodal AFM. A series of experiments and numerical simulations shows that the primary cause of the contrast reversals is not the choice of eigenmode itself (e.g., second versus fourth, but rather the relative kinetic energy between the higher eigenmode and the first eigenmode. This leads to the identification of three distinct imaging regimes in bimodal AFM. This result, which is applicable even to traditional bimodal AFM, should allow researchers to choose cantilever and operating parameters in a more rational manner in order to optimize resolution and contrast during nanoscale imaging of materials.

AFM indentation study of breast cancer cells

International Nuclear Information System (INIS)

Li, Q.S.; Lee, G.Y.H.; Ong, C.N.; Lim, C.T.

2008-01-01

Mechanical properties of individual living cells are known to be closely related to the health and function of the human body. Here, atomic force microscopy (AFM) indentation using a micro-sized spherical probe was carried out to characterize the elasticity of benign (MCF-10A) and cancerous (MCF-7) human breast epithelial cells. AFM imaging and confocal fluorescence imaging were also used to investigate their corresponding sub-membrane cytoskeletal structures. Malignant (MCF-7) breast cells were found to have an apparent Young's modulus significantly lower (1.4-1.8 times) than that of their non-malignant (MCF-10A) counterparts at physiological temperature (37 deg. C), and their apparent Young's modulus increase with loading rate. Both confocal and AFM images showed a significant difference in the organization of their sub-membrane actin structures which directly contribute to their difference in cell elasticity. This change may have facilitated easy migration and invasion of malignant cells during metastasis

Phase shifting-based debris effect detection in USV-assisted AFM nanomachining

Energy Technology Data Exchange (ETDEWEB)

Shi, Jialin [State Key Laboratory of Robotics, Shenyang Institute of Automation, Chinese Academy of Sciences (CAS), Shenyang, Liaoning 110016 (China); University of the Chinese Academy of Sciences, Beijing 100049 (China); Beijing Advanced Innovation Center for Imaging Technology, Capital Normal University, Beijing 100049 (China); Liu, Lianqing, E-mail: lianqingliu@sia.cn [State Key Laboratory of Robotics, Shenyang Institute of Automation, Chinese Academy of Sciences (CAS), Shenyang, Liaoning 110016 (China); Yu, Peng; Cong, Yang [State Key Laboratory of Robotics, Shenyang Institute of Automation, Chinese Academy of Sciences (CAS), Shenyang, Liaoning 110016 (China); Li, Guangyong [Department of Electrical and Computer Engineering, University of Pittsburgh, Pittsburgh, PA 15213 (United States)

2017-08-15

Highlights: • The mechanism of the debris effect on machining depth in force control mode operation is analyzed. • The relationship between phase shifting and pile-up of debris is investigated. • The phase shifting-based method is hardly affected by the pile-up of debris. • Debris effect detection by phase shifting-based method is achived. - Abstract: Atomic force microscopy (AFM) mechanical-based lithography attracts much attention in nanomanufacturing due to its advantages of low cost, high precision and high resolution. However, debris effects during mechanical lithography often lead to an unstable machining process and inaccurate results, which limits further applications of AFM-based lithography. There is a lack of a real-time debris detection approach, which is the prerequisite to eventually eliminating the influence of the debris, and of a method that can solve the above problems well. The ultrasonic vibration (USV)-assisted AFM has the ability to sense the machining depth in real time by detecting the phase shifting of cantilever. However, whether the pile-up of debris affect the phase response of cantilever is still lack of investigation. Therefore, we analyzed the mechanism of the debris effect on force control mode and investigated the relationship between phase shifting and pile-up of debris. Theoretical analysis and experimental results reveal that the pile-up of debris have negligible effect on phase shifting of cantilever. Therefore, the phase shifting-based method can detect the debris effect on machining depth in force control mode of AFM machining.

AFM (Atomic force microscope and its use in studying the surface

Directory of Open Access Journals (Sweden)

Škvarla Jiří

1996-06-01

Full Text Available The paper summarizes the present knowledge about the use of AFM in the mineral processing research. First, the development and fundamentals of the AFM imaging are presented in relation to other imaging techniques (especially STM, Scanning tunneling microscope. Further, the role of the sensing tip-surface interactions is mentioned. Finally, the surface force measurements in the AFM force calibration mode are diskussed.

Helium ion beam induced growth of hammerhead AFM probes

NARCIS (Netherlands)

Nanda, G.; Veldhoven, E. van; Maas, D.J.; Sadeghian Marnani, H.; Alkemade, P.F.A.

2015-01-01

The authors report the direct-write growth of hammerhead atomic force microscope (AFM) probes by He+ beam induced deposition of platinum-carbon. In order to grow a thin nanoneedle on top of a conventional AFM probe, the authors move a focused He+ beam during exposure to a PtC precursor gas. In the

Immobilisation of living bacteria for AFM imaging under physiological conditions

International Nuclear Information System (INIS)

Louise Meyer, Rikke; Zhou, Xingfei; Tang, Lone; Arpanaei, Ayyoob; Kingshott, Peter; Besenbacher, Flemming

2010-01-01

Atomic force microscopy (AFM) holds great potential for studying the nanoscale surface structures of living cells, and to measure their interactions with abiotic surfaces, other cells, or specific biomolecules. However, the application of AFM in microbiology is challenging due to the difficulty of immobilising bacterial cells to a flat surface without changing the cell surface properties or cell viability. We have performed an extensive and thorough study of how to functionalise surfaces in order to immobilise living bacteria for AFM studies in liquid environments. Our aim was to develop a scheme which allows bacterial cells to be immobilised to a flat surface with sufficient strength to avoid detachment during the AFM scanning, and without affecting cell surface chemistry, structure, and viability. We compare and evaluate published methods, and present a new, reproducible, and generally applicable scheme for immobilising bacteria cells for an AFM imaging. Bacterial cells were immobilised to modified glass surfaces by physical confinement of cells in microwells, physisorption to positively charged surfaces, covalent binding to amine- or carboxyl-terminated surfaces, and adsorption to surfaces coated with highly adhesive polyphenolic proteins originating from the mussel Mytilus edulis. Living cells could be immobilised with all of these approaches, but many cells detached when immobilised by electrostatic interactions and imaged in buffers like PBS or MOPS. Cells were more firmly attached when immobilised by covalent binding, although some cells still detached during AFM imaging. The most successful method revealed was immobilisation by polyphenolic proteins, which facilitated firm immobilisation of the cells. Furthermore, the cell viability was not affected by this immobilisation scheme, and adhesive proteins thus provide a fast, reproducible, and generally applicable scheme for immobilising living bacteria for an AFM imaging.

Optimization of specimen preparation of thin cell section for AFM observation

Energy Technology Data Exchange (ETDEWEB)

Li Xinhui [Nanobiology Laboratory, Bio-X Life Science Research Center, School of Life Science and Biotechnology, Shanghai Jiao Tong University, 800 Dongchuan Road, Minhang District, Shanghai 200240 (China); Ji Tong [Department of Oral and Maxillofacial Surgery, School of Stomatology, Affiliated Ninth People' s Hospital, Medical School, Shanghai Jiao Tong University, Shanghai 200011 (China); Hu Jun [Nanobiology Laboratory, Bio-X Life Science Research Center, School of Life Science and Biotechnology, Shanghai Jiao Tong University, 800 Dongchuan Road, Minhang District, Shanghai 200240 (China); Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201800 (China); Sun Jielin [Nanobiology Laboratory, Bio-X Life Science Research Center, School of Life Science and Biotechnology, Shanghai Jiao Tong University, 800 Dongchuan Road, Minhang District, Shanghai 200240 (China)], E-mail: jlsun@sjtu.edu.cn

2008-08-15

High resolution imaging of intracellular structures of ultrathin cell section samples is critical to the performance of precise manipulation by atomic force microscopy (AFM). Here, we test the effect of multiple factors during section sample preparation on the quality of the AFM image. These factors include the embedding materials, the annealing process of the specimen block, section thickness, and section side. We found that neither the embedding materials nor the temperature and speed of the annealing process has any effect on AFM image resolution. However, the section thickness and section side significantly affect the surface topography and AFM image resolution. By systematically testing the image quality of both sides of cell sections over a wide range of thickness (40-1000 nm), we found that the best resolution was obtained with upper-side sections approximately 50-100 nm thick. With these samples, we could observe precise structure details of the cell, including its membrane, nucleoli, and other organelles. Similar results were obtained for other cell types, including Tca8113, C6, and ECV-304. In brief, by optimizing the condition of ultrathin cell section preparation, we were able to obtain high resolution intracellular AFM images, which provide an essential basis for further AFM manipulation.

Accurate Calibration and Uncertainty Estimation of the Normal Spring Constant of Various AFM Cantilevers

Directory of Open Access Journals (Sweden)

Yunpeng Song

2015-03-01

Full Text Available Measurement of force on a micro- or nano-Newton scale is important when exploring the mechanical properties of materials in the biophysics and nanomechanical fields. The atomic force microscope (AFM is widely used in microforce measurement. The cantilever probe works as an AFM force sensor, and the spring constant of the cantilever is of great significance to the accuracy of the measurement results. This paper presents a normal spring constant calibration method with the combined use of an electromagnetic balance and a homemade AFM head. When the cantilever presses the balance, its deflection is detected through an optical lever integrated in the AFM head. Meanwhile, the corresponding bending force is recorded by the balance. Then the spring constant can be simply calculated using Hooke’s law. During the calibration, a feedback loop is applied to control the deflection of the cantilever. Errors that may affect the stability of the cantilever could be compensated rapidly. Five types of commercial cantilevers with different shapes, stiffness, and operating modes were chosen to evaluate the performance of our system. Based on the uncertainty analysis, the expanded relative standard uncertainties of the normal spring constant of most measured cantilevers are believed to be better than 2%.

High-speed AFM for Studying Dynamic Biomolecular Processes

Science.gov (United States)

Ando, Toshio

2008-03-01

Biological molecules show their vital activities only in aqueous solutions. It had been one of dreams in biological sciences to directly observe biological macromolecules (protein, DNA) at work under a physiological condition because such observation is straightforward to understanding their dynamic behaviors and functional mechanisms. Optical microscopy has no sufficient spatial resolution and electron microscopy is not applicable to in-liquid samples. Atomic force microscopy (AFM) can visualize molecules in liquids at high resolution but its imaging rate was too low to capture dynamic biological processes. This slow imaging rate is because AFM employs mechanical probes (cantilevers) and mechanical scanners to detect the sample height at each pixel. It is quite difficult to quickly move a mechanical device of macroscopic size with sub-nanometer accuracy without producing unwanted vibrations. It is also difficult to maintain the delicate contact between a probe tip and fragile samples. Two key techniques are required to realize high-speed AFM for biological research; fast feedback control to maintain a weak tip-sample interaction force and a technique to suppress mechanical vibrations of the scanner. Various efforts have been carried out in the past decade to materialize high-speed AFM. The current high-speed AFM can capture images on video at 30-60 frames/s for a scan range of 250nm and 100 scan lines, without significantly disturbing week biomolecular interaction. Our recent studies demonstrated that this new microscope can reveal biomolecular processes such as myosin V walking along actin tracks and association/dissociation dynamics of chaperonin GroEL-GroES that occurs in a negatively cooperative manner. The capacity of nanometer-scale visualization of dynamic processes in liquids will innovate on biological research. In addition, it will open a new way to study dynamic chemical/physical processes of various phenomena that occur at the liquid-solid interfaces.

Adhesion forces in AFM of redox responsive polymer grafts: Effects of tip hydrophilicity

NARCIS (Netherlands)

Feng, Xueling; Kieviet, B.D.; Song, Jing; Schön, Peter Manfred; Vancso, Gyula J.

2014-01-01

The adherence between silicon nitride AFM tips and redox-active poly(ferrocenylsilanes) (PFS) grafts ongold was investigated by electrochemical AFM force spectroscopy. Before the adhesion measurementssilicon nitride AFM probes were cleaned with organic solvents (acetone and ethanol) or piranha

Biophysical analysis of bacterial and viral systems. A shock tube study of bio-aerosols and a correlated AFM/nanosims investigation of vaccinia virus

Energy Technology Data Exchange (ETDEWEB)

Gates, Sean Damien [Stanford Univ., CA (United States)

2013-05-01

The work presented herein is concerned with the development of biophysical methodology designed to address pertinent questions regarding the behavior and structure of select pathogenic agents. Two distinct studies are documented: a shock tube analysis of endospore-laden bio-aerosols and a correlated AFM/NanoSIMS study of the structure of vaccinia virus.

Analysis of Nanodomain Composition in High-Impact Polypropylene by Atomic Force Microscopy-Infrared.

Science.gov (United States)

Tang, Fuguang; Bao, Peite; Su, Zhaohui

2016-05-03

In this paper, compositions of nanodomains in a commercial high-impact polypropylene (HIPP) were investigated by an atomic force microscopy-infrared (AFM-IR) technique. An AFM-IR quantitative analysis method was established for the first time, which was then employed to analyze the polyethylene content in the nanoscopic domains of the rubber particles dispersed in the polypropylene matrix. It was found that the polyethylene content in the matrix was close to zero and was high in the rubbery intermediate layers, both as expected. However, the major component of the rigid cores of the rubber particles was found to be polypropylene rather than polyethylene, contrary to what was previously believed. The finding provides new insight into the complicated structure of HIPPs, and the AFM-IR quantitative method reported here offers a useful tool for assessing compositions of nanoscopic domains in complex polymeric systems.

Micromechanical Characterization of Complex Polypropylene Morphologies by HarmoniX AFM

Directory of Open Access Journals (Sweden)

S. Liparoti

2017-01-01

Full Text Available This paper examines the capability of the HarmoniX Atomic Force Microscopy (AFM technique to draw accurate and reliable micromechanical characterization of complex polymer morphologies generally found in conventional thermoplastic polymers. To that purpose, injection molded polypropylene samples, containing representative morphologies, have been characterized by HarmoniX AFM. Mapping and distributions of mechanical properties of the samples surface are determined and analyzed. Effects of sample preparation and test conditions are also analyzed. Finally, the AFM determination of surface elastic moduli has been compared with that obtained by indentation tests, finding good agreement among the results.

tRNA conjugation with chitosan nanoparticles: An AFM imaging study.

Science.gov (United States)

Agudelo, D; Kreplak, L; Tajmir-Riahi, H A

2016-04-01

The conjugation of tRNA with chitosan nanoparticles of different sizes 15,100 and 200 kDa was investigated in aqueous solution using multiple spectroscopic methods and atomic force microscopy (AFM). Structural analysis showed that chitosan binds tRNA via G-C and A-U base pairs as well as backbone PO2 group, through electrostatic, hydrophilic and H-bonding contacts with overall binding constants of KCh-15-tRNA=4.1 (±0.60)×10(3)M(-1), KCh-100-tRNA=5.7 (±0.8)×10(3)M(-1) and KCh-200-tRNA=1.2 (±0.3)×10(4)M(-1). As chitosan size increases more stable polymer-tRNA conjugate is formed. AFM images showed major tRNA aggregation and particle formation occurred as chitosan concentration increased. Even though chitosan induced major biopolymer structural changes, tRNA remains in A-family structure. Copyright © 2015 Elsevier B.V. All rights reserved.

Direct manipulation of intracellular stress fibres using a hook-shaped AFM probe

International Nuclear Information System (INIS)

Machida, Shinichi; Watanabe-Nakayama, Takahiro; Harada, Ichiro; Afrin, Rehana; Nakayama, Tomonobu; Ikai, Atsushi

2010-01-01

Atomic force microscopy (AFM) is a highly successful technique for imaging nanometre-sized samples and measuring pico- to nano-newton forces acting between atoms and molecules. When it comes to the manipulation of larger samples with forces of tens and hundreds of nano-newtons, however, the present chemistry-based modification protocols for functionalizing AFM cantilevers to achieve the formation of covalent/non-covalent linkages between the AFM probe and the sample surface do not produce strong enough bonds. For the purpose of measuring the fracture strength and other mechanical properties of stress fibres (SFs) in living as well as semi-intact fibroblast cells, we fabricated an AFM probe with a hooking function by focused ion beam technology and used the AFM probe hook to capture, pull and eventually sever a chosen SF labelled with green or red fluorescent protein.

Optimization of functionalization conditions for protein analysis by AFM

Energy Technology Data Exchange (ETDEWEB)

Arroyo-Hernández, María, E-mail: maria.arroyo@ctb.upm.es [Centro de Tecnología Biomédica, Universidad Politécnica de Madrid, 28223 Pozuelo de Alarcón, Madrid (Spain); Departamento de Ciencia de Materiales, ETSI Caminos, Canales y Puertos, Universidad Politécnica de Madrid, 28040 Madrid (Spain); Daza, Rafael; Pérez-Rigueiro, Jose; Elices, Manuel; Nieto-Márquez, Jorge; Guinea, Gustavo V. [Centro de Tecnología Biomédica, Universidad Politécnica de Madrid, 28223 Pozuelo de Alarcón, Madrid (Spain); Departamento de Ciencia de Materiales, ETSI Caminos, Canales y Puertos, Universidad Politécnica de Madrid, 28040 Madrid (Spain)

2014-10-30

Highlights: • Highest fluorescence is obtained for central conditions. • Largest primary amine contribution is obtained for central conditions. • RMS roughness is smaller than 1 nm for all functional films. • Selected deposition conditions lead to proper RMS and functionality values. • LDH proteins adsorbed on AVS-films were observed by AFM. - Abstract: Activated vapor silanization (AVS) is used to functionalize silicon surfaces through deposition of amine-containing thin films. AVS combines vapor silanization and chemical vapor deposition techniques and allows the properties of the functionalized layers (thickness, amine concentration and topography) to be controlled by tuning the deposition conditions. An accurate characterization is performed to correlate the deposition conditions and functional-film properties. In particular, it is shown that smooth surfaces with a sufficient surface density of amine groups may be obtained with this technique. These surfaces are suitable for the study of proteins with atomic force microscopy.

Quantitative analysis of receptor imaging

International Nuclear Information System (INIS)

Fu Zhanli; Wang Rongfu

2004-01-01

Model-based methods for quantitative analysis of receptor imaging, including kinetic, graphical and equilibrium methods, are introduced in detail. Some technical problem facing quantitative analysis of receptor imaging, such as the correction for in vivo metabolism of the tracer and the radioactivity contribution from blood volume within ROI, and the estimation of the nondisplaceable ligand concentration, is also reviewed briefly

Diagnostic performance of semi-quantitative and quantitative stress CMR perfusion analysis: a meta-analysis.

Science.gov (United States)

van Dijk, R; van Assen, M; Vliegenthart, R; de Bock, G H; van der Harst, P; Oudkerk, M

2017-11-27

Stress cardiovascular magnetic resonance (CMR) perfusion imaging is a promising modality for the evaluation of coronary artery disease (CAD) due to high spatial resolution and absence of radiation. Semi-quantitative and quantitative analysis of CMR perfusion are based on signal-intensity curves produced during the first-pass of gadolinium contrast. Multiple semi-quantitative and quantitative parameters have been introduced. Diagnostic performance of these parameters varies extensively among studies and standardized protocols are lacking. This study aims to determine the diagnostic accuracy of semi- quantitative and quantitative CMR perfusion parameters, compared to multiple reference standards. Pubmed, WebOfScience, and Embase were systematically searched using predefined criteria (3272 articles). A check for duplicates was performed (1967 articles). Eligibility and relevance of the articles was determined by two reviewers using pre-defined criteria. The primary data extraction was performed independently by two researchers with the use of a predefined template. Differences in extracted data were resolved by discussion between the two researchers. The quality of the included studies was assessed using the 'Quality Assessment of Diagnostic Accuracy Studies Tool' (QUADAS-2). True positives, false positives, true negatives, and false negatives were subtracted/calculated from the articles. The principal summary measures used to assess diagnostic accuracy were sensitivity, specificity, andarea under the receiver operating curve (AUC). Data was pooled according to analysis territory, reference standard and perfusion parameter. Twenty-two articles were eligible based on the predefined study eligibility criteria. The pooled diagnostic accuracy for segment-, territory- and patient-based analyses showed good diagnostic performance with sensitivity of 0.88, 0.82, and 0.83, specificity of 0.72, 0.83, and 0.76 and AUC of 0.90, 0.84, and 0.87, respectively. In per territory

AFM topographies of densely packed nanoparticles: a quick way to determine the lateral size distribution by autocorrelation function analysis

International Nuclear Information System (INIS)

Fekete, L.; Kůsová, K.; Petrák, V.; Kratochvílová, I.

2012-01-01

The distribution of sizes is one of the basic characteristics of nanoparticles. Here, we propose a novel way to determine the lateral distribution of sizes from AFM topographies. Our algorithm is based on the autocorrelation function and can be applied both on topographies containing spatially separated and densely packed nanoparticles as well as on topographies of polycrystalline films. As no manual treatment is required, this algorithm can be easily automatable for batch processing. The algorithm works in principle with any kind of spatially mapped information (AFM current maps, optical microscope images, etc.), and as such has no size limitations. However, in the case of AFM topographies, the tip/sample convolution effects will be the factor limiting the smallest size to which the algorithm is applicable. Here, we demonstrate the usefulness of this algorithm on objects with sizes ranging between 20 nm and 1.5 μm.

AFM picking-up manipulation of the metaphase chromosome fragment by using the tweezers-type probe

International Nuclear Information System (INIS)

Yamanaka, Keiichiro; Saito, Masato; Shichiri, Motoharu; Sugiyama, Sigeru; Takamura, Yuzuru; Hashiguchi, Gen; Tamiya, Eiichi

2008-01-01

We have studied the development of a new procedure based on atomic force microscopy (AFM) for the analysis of metaphase chromosome. The aim of this study was to obtain detailed information about the specific locations of genes on the metaphase chromosome. In this research, we performed the manipulation of the metaphase chromosome by using novel AFM probes to obtain chromosome fragments of a smaller size than the ones obtained using the conventional methods, such as glass microneedles. We could pick up the fragment of the metaphase chromosome dissected by the knife-edged probe by using our tweezers-type probe

Self-assembled silver nanoparticles monolayers on mica-AFM, SEM, and electrokinetic characteristics

International Nuclear Information System (INIS)

Oćwieja, Magdalena; Morga, Maria; Adamczyk, Zbigniew

2013-01-01

A monodisperse silver particle suspension was produced by a chemical reduction method in an aqueous medium using sodium citrate. The average particle size determined by dynamic light scattering (DLS), transmission electron microscopy (TEM), and atomic force microscopy (AFM) was 28.5 nm. The DLS measurements confirmed that the suspension was stable for the ionic strength up to 3 × 10 −2 M NaCl. The electrophoretic mobility measurements revealed that the electrokinetic charge of particles was negative for pH range 3–10, assuming −50 e for pH = 9 and 0.01 M NaCl. Using the suspension, silver particle monolayers on mica modified by poly(allylamine hydrochloride) were produced under diffusion-controlled transport. Monolayer coverage, quantitatively determined by AFM and SEM, was regulated within broad limits by adjusting the nanoparticle deposition time. This allowed one to uniquely express the zeta potential of silver monolayers, determined by the in situ streaming potential measurements, in terms of particle coverage. Such dependencies obtained for various ionic strengths and pH, were successfully interpreted in terms of the 3D electrokinetic model. A universal calibrating graph was produced in this way, enabling one to determine silver monolayer coverage from the measured value of the streaming potential. Our experimental data prove that it is feasible to produce uniform and stable silver particle monolayers of well-controlled coverage and defined electrokinetic properties.

Modification of AFM Tips for Facilitating Picking-up of Nanoparticles

International Nuclear Information System (INIS)

Peng, Wang; Hai-Jun, Yang; Hua-Bin, Wang; Hai, Li; Xin-Yan, Wang; Ying, Wang; Jun-Hong, Lü; Bin, Li; Yi, Zhang; Jun, Hu

2008-01-01

The radius of atomic force microscope (AFM) tip is a key factor that influences nonspecific interactions between AFM tip and nanoparticles. Generally, a tip with larger radius contributes to a higher efficiency of picking up nanoparticles. We provide two methods for modifying the AFM tip: one is to wear a tip apex on a solid substrate and the other is to coat a tip with poly (dimethylsiloxane) (PDMS). Both the approaches can enhance the adhesion force between the tip and nanoparticles by increasing tip radius. The experimental results show that a modified tip, compared to an unmodified one, achieves six-fold efficiency improvement in the capture of targeted colloidal gold nanoparticles. (general)

A Multifunctional Frontloading Approach for Repeated Recycling of a Pressure-Controlled AFM Micropipette.

Directory of Open Access Journals (Sweden)

Phillip Roder

Full Text Available Fluid force microscopy combines the positional accuracy and force sensitivity of an atomic force microscope (AFM with nanofluidics via a microchanneled cantilever. However, adequate loading and cleaning procedures for such AFM micropipettes are required for various application situations. Here, a new frontloading procedure is described for an AFM micropipette functioning as a force- and pressure-controlled microscale liquid dispenser. This frontloading procedure seems especially attractive when using target substances featuring high costs or low available amounts. Here, the AFM micropipette could be filled from the tip side with liquid from a previously applied droplet with a volume of only a few μL using a short low-pressure pulse. The liquid-loaded AFM micropipettes could be then applied for experiments in air or liquid environments. AFM micropipette frontloading was evaluated with the well-known organic fluorescent dye rhodamine 6G and the AlexaFluor647-labeled antibody goat anti-rat IgG as an example of a larger biological compound. After micropipette usage, specific cleaning procedures were tested. Furthermore, a storage method is described, at which the AFM micropipettes could be stored for a few hours up to several days without drying out or clogging of the microchannel. In summary, the rapid, versatile and cost-efficient frontloading and cleaning procedure for the repeated usage of a single AFM micropipette is beneficial for various application situations from specific surface modifications through to local manipulation of living cells, and provides a simplified and faster handling for already known experiments with fluid force microscopy.

Analysis the effect of different geometries of AFM's cantilever on the dynamic behavior and the critical forces of three-dimensional manipulation

International Nuclear Information System (INIS)

Korayem, Moharam Habibnejad; Saraie, Maniya B.; Saraee, Mahdieh B.

2017-01-01

An important challenge when using an atomic force microscope (AFM) is to be able to control the force exerted by the AFM for performing various tasks. Nevertheless, the exerted force is proportional to the deflection of the AFM cantilever, which itself is affected by a cantilever's stiffness coefficient. Many papers have been published so far on the methods of obtaining the stiffness coefficients of AFM cantilevers in 2D; however, a comprehensive model is yet to be presented on 3D cantilever motion. The discrepancies between the equations of the 2D and 3D analysis are due to the number and direction of forces and moments that are applied to a cantilever. Moreover, in the 3D analysis, contrary to the 2D analysis, due to the interaction between the forces and moments applied on a cantilever, its stiffness values cannot be separately expressed for each direction; and instead, a stiffness matrix should be used to correctly derive the relevant equations. In this paper, 3D stiffness coefficient matrices have been obtained for three common cantilever geometries including the rectangular, V-shape and dagger-shape cantilevers. The obtained equations are validated by two methods. In the first approach, the Finite Element Method is combined with the cantilever deflection values computed by using the obtained stiffness matrices. In the second approach, by reducing the problem's parameters, the forces applied on a cantilever along different directions are compared with each other in 2D and 3D cases. Then the 3D manipulation of a stiff nanoparticle is modeled and simulated by using the stiffness matrices obtained for the three cantilever geometries. The obtained results indicate that during the manipulation process, the dagger-shaped and rectangular cantilevers exert the maximum and minimum amounts of forces on the stiff nanoparticle, respectively. Also, by examining the effects of different probe tip geometries, it is realized that a probe tip of cylindrical geometry exerts the

Single molecule transcription profiling with AFM

International Nuclear Information System (INIS)

Reed, Jason; Mishra, Bud; Pittenger, Bede; Magonov, Sergei; Troke, Joshua; Teitell, Michael A; Gimzewski, James K

2007-01-01

Established techniques for global gene expression profiling, such as microarrays, face fundamental sensitivity constraints. Due to greatly increasing interest in examining minute samples from micro-dissected tissues, including single cells, unorthodox approaches, including molecular nanotechnologies, are being explored in this application. Here, we examine the use of single molecule, ordered restriction mapping, combined with AFM, to measure gene transcription levels from very low abundance samples. We frame the problem mathematically, using coding theory, and present an analysis of the critical error sources that may serve as a guide to designing future studies. We follow with experiments detailing the construction of high density, single molecule, ordered restriction maps from plasmids and from cDNA molecules, using two different enzymes, a result not previously reported. We discuss these results in the context of our calculations

The formation of liquid bridge in different operating modes of AFM

Science.gov (United States)

Wei, Zheng; Sun, Yan; Ding, WenXuan; Wang, ZaiRan

2016-09-01

The liquid bridge is one of the principal factors that cause artifacts in ambient-pressure atomic force microscope (AFM) images. Additionally, it is the main component of the adhesion force in ambient conditions. To understand the AFM imaging mechanism and the sample characteristics, it is essential to study the liquid bridge. This study interprets the physical mechanism involved in liquid bridge formation, which is composed of three different physical processes: the squeezing process, capillary condensation, and liquid film flow. We discuss the contributions of these three mechanisms to the volume and the capillary force of the liquid bridge in different AFM operation modes.

Noncontact AFM Imaging of Atomic Defects on the Rutile TiO2 (110) Surface

DEFF Research Database (Denmark)

Lauritsen, Jeppe Vang

2015-01-01

The atomic force microscope (AFM) operated in the noncontact mode (nc-AFM) offers a unique tool for real space, atomic-scale characterisation of point defects and molecules on surfaces, irrespective of the substrate being electrically conducting or non-conducting. The nc-AFM has therefore in rece...

Fabrication of cone-shaped boron doped diamond and gold nanoelectrodes for AFM-SECM

Energy Technology Data Exchange (ETDEWEB)

Avdic, A; Lugstein, A; Bertagnolli, E [Solid State Electronics Institute, Vienna University of Technology, Floragasse 7, 1040 Vienna (Austria); Wu, M; Gollas, B [Competence Centre for Electrochemical Surface Technology, Viktor Kaplan Strasse 2, 2700 Wiener Neustadt (Austria); Pobelov, I; Wandlowski, T [Department of Chemistry and Biochemistry, University of Bern, Freiestrasse 3, 3012 Bern (Switzerland); Leonhardt, K; Denuault, G, E-mail: alois.lugstein@tuwien.ac.at [School of Chemistry, University of Southampton, Highfield, Southampton SO17 1BJ (United Kingdom)

2011-04-08

We demonstrate a reliable microfabrication process for a combined atomic force microscopy (AFM) and scanning electrochemical microscopy (SECM) measurement tool. Integrated cone-shaped sensors with boron doped diamond (BDD) or gold (Au) electrodes were fabricated from commercially available AFM probes. The sensor formation process is based on mature semiconductor processing techniques, including focused ion beam (FIB) machining, and highly selective reactive ion etching (RIE). The fabrication approach preserves the geometry of the original AFM tips resulting in well reproducible nanoscaled sensors. The feasibility and functionality of the fully featured tips are demonstrated by cyclic voltammetry, showing good agreement between the measured and calculated currents of the cone-shaped AFM-SECM electrodes.

AFM study of structure influence on butterfly wings coloration

OpenAIRE

Dallaeva, Dinara; Tománek, Pavel

2012-01-01

This study describes the structural coloration of the butterfly Vanessa Atalanta wings and shows how the atomic force microscopy (AFM) can be applied to the study of wings morphology and wings surface behavior under the temperature. The role of the wings morphology in colors was investigated. Different colors of wings have different topology and can be identified by them. AFM in semi-contact mode was used to study the wings surface. The wing surface area, which is close to the butterfly body,...

Transient Tip-Sample Interactions in High-Speed AFM Imaging of 3D nano structures

NARCIS (Netherlands)

Keyvani Janbahan, A.; Sadeghian Marnani, H; Goosen, H.; Keulen, F. van

2015-01-01

The maximum amount of repulsive force applied to the surface plays a very important role in damage of tip or sample in Atomic Force Microscopy(AFM). So far, many investigations have focused on peak repulsive forces in tapping mode AFM in steady state conditions. However, it is known that AFM could

AFM imaging of functionalized carbon nanotubes on biological membranes

International Nuclear Information System (INIS)

Lamprecht, C; Danzberger, J; Rangl, M; Gruber, H J; Hinterdorfer, P; Kienberger, F; Ebner, A; Liashkovich, I; Neves, V; Heister, E; Coley, H M; McFadden, J; Flahaut, E

2009-01-01

Multifunctional carbon nanotubes are promising for biomedical applications as their nano-size, together with their physical stability, gives access into the cell and various cellular compartments including the nucleus. However, the direct and label-free detection of carbon nanotube uptake into cells is a challenging task. The atomic force microscope (AFM) is capable of resolving details of cellular surfaces at the nanometer scale and thus allows following of the docking of carbon nanotubes to biological membranes. Here we present topographical AFM images of non-covalently functionalized single walled (SWNT) and double walled carbon nanotubes (DWNT) immobilized on different biological membranes, such as plasma membranes and nuclear envelopes, as well as on a monolayer of avidin molecules. We were able to visualize DWNT on the nuclear membrane while at the same time resolving individual nuclear pore complexes. Furthermore, we succeeded in localizing individual SWNT at the border of incubated cells and in identifying bundles of DWNT on cell surfaces by AFM imaging.

Near-Field Spectroscopy with Nanoparticles Deposited by AFM

Science.gov (United States)

Anderson, Mark S.

2008-01-01

An alternative approach to apertureless near-field optical spectroscopy involving an atomic-force microscope (AFM) entails less complexity of equipment than does a prior approach. The alternative approach has been demonstrated to be applicable to apertureless near-field optical spectroscopy of the type using an AFM and surface enhanced Raman scattering (SERS), and is expected to be equally applicable in cases in which infrared or fluorescence spectroscopy is used. Apertureless near-field optical spectroscopy is a means of performing spatially resolved analyses of chemical compositions of surface regions of nanostructured materials. In apertureless near-field spectroscopy, it is common practice to utilize nanostructured probe tips or nanoparticles (usually of gold) having shapes and dimensions chosen to exploit plasmon resonances so as to increase spectroscopic-signal strengths. To implement the particular prior approach to which the present approach is an alternative, it is necessary to integrate a Raman spectrometer with an AFM and to utilize a special SERS-active probe tip. The resulting instrumentation system is complex, and the tasks of designing and constructing the system and using the system to acquire spectro-chemical information from nanometer-scale regions on a surface are correspondingly demanding.

Dynamic behavior of RNA nanoparticles analyzed by AFM on a mica/air interface.

Science.gov (United States)

Sajja, Sameer; Chandler, Morgan; Federov, Dmitry; Kasprzak, Wojciech K; Lushnikov, Alexander Y; Viard, Mathias; Shah, Ankit; Dang, Dylan; Dahl, Jared; Worku, Beamlak; Dobrovolskaia, Marina A; Krasnoslobodtsev, Alexey; Shapiro, Bruce A; Afonin, Kirill A

2018-04-18

RNA is an attractive biopolymer for engineering self-assembling materials suitable for biomedical applications. Previously, programmable hexameric RNA rings were developed for the controlled delivery of up to six different functionalities. To increase the potential for functionalization with little impact on nanoparticle topology, we introduce gaps into the double-stranded regions of the RNA rings. Molecular dynamic simulations are used to assess the dynamic behavior and the changes in the flexibility of novel designs. The changes suggested by simulations, however, cannot be clearly confirmed by the conventional techniques such as non-denaturing polyacrylamide gel electrophoresis (native-PAGE) and dynamic light scattering (DLS). Also, an in vitro analysis in primary cultures of human peripheral blood mononuclear cells does not reveal any discrepancy in immunological recognition of new assemblies. To address these deficiencies, we introduce a computer-assisted quantification strategy. This strategy is based on an algorithmic atomic force microscopy (AFM)-resolved deformation analysis of the RNA nanoparticles studied on a mica/air interface. We validate this computational method by manual image analysis and fitting it to the simulation-predicted results. The presented nanoparticle modification strategy and subsequent AFM-based analysis are anticipated to provide a broad spectrum approach for the future development of nucleic acid-based nanotechnology.

Self-assembled silver nanoparticles monolayers on mica-AFM, SEM, and electrokinetic characteristics.

Science.gov (United States)

Oćwieja, Magdalena; Morga, Maria; Adamczyk, Zbigniew

2013-03-01

A monodisperse silver particle suspension was produced by a chemical reduction method in an aqueous medium using sodium citrate. The average particle size determined by dynamic light scattering (DLS), transmission electron microscopy (TEM), and atomic force microscopy (AFM) was 28.5 nm. The DLS measurements confirmed that the suspension was stable for the ionic strength up to 3 × 10 -2  M NaCl. The electrophoretic mobility measurements revealed that the electrokinetic charge of particles was negative for pH range 3-10, assuming -50  e for pH = 9 and 0.01 M NaCl. Using the suspension, silver particle monolayers on mica modified by poly(allylamine hydrochloride) were produced under diffusion-controlled transport. Monolayer coverage, quantitatively determined by AFM and SEM, was regulated within broad limits by adjusting the nanoparticle deposition time. This allowed one to uniquely express the zeta potential of silver monolayers, determined by the in situ streaming potential measurements, in terms of particle coverage. Such dependencies obtained for various ionic strengths and pH, were successfully interpreted in terms of the 3D electrokinetic model. A universal calibrating graph was produced in this way, enabling one to determine silver monolayer coverage from the measured value of the streaming potential. Our experimental data prove that it is feasible to produce uniform and stable silver particle monolayers of well-controlled coverage and defined electrokinetic properties.

Coalescence and movement of nanobubbles studied with tapping mode AFM and tip-bubble interaction analysis

International Nuclear Information System (INIS)

Bhushan, Bharat; Wang Yuliang; Maali, Abdelhamid

2008-01-01

Imaging of a polystyrene (PS) coated silicon wafer immersed in deionized (DI) water was conducted using atomic force microscopy (AFM) in the tapping mode (TMAFM). As reported earlier, spherical cap-like domains, referred to as nanobubbles, were observed to be distributed on the PS surface. Experiments reveal that, in addition to the well-known parameter of scan load, scan speed is also an important parameter which affects nanobubble coalescence. The process of nanobubble coalescence was studied. It was found that during coalescence, small nanobubbles were easily moved and merged into bigger ones. Based on the interaction between the AFM cantilever tip and a bubble in the so-called force modulation mode of TMAFM, bubble height and adhesive force information for a given bubble was extracted. A viscoelastic model is used to obtain the interaction stiffness and damping coefficient, which provides a method to obtain the mechanical properties of nanobubbles. The model was further used to study the effect of surface tension force on attractive interaction force and contact angle hysteresis on the changes of the interaction damping coefficient during tip-bubble interaction.

Fracture Growth Testing of Titanium 6AL-4V in AF-M315E

Science.gov (United States)

Sampson, Jeffrey W.; Martinez, Jonathan; McLean, Christopher

2015-01-01

The Green Propellant Infusion Mission (GPIM) will demonstrate the performance of AF-M315E monopropellant in orbit. Flight certification requires a safe-life analysis of the titanium alloy fuel tank to ensure inherent flaws will not cause failure during the design life. Material property inputs for this analysis require testing to determine the stress intensity factor for environmentally-assisted cracking (K (sub EAC)) of Ti 6Al-4V in combination with the AF-M315E monopropellant. Testing of single-edge notched specimens SE(B) representing the bulk tank membrane and weld material were performed in accordance with ASTM E1681. Specimens with fatigue pre-cracks were loaded into test fixtures so that the crack tips were exposed to the monopropellant at 50 degrees Centigrade for a duration of 1,000 hours. Specimens that did not fail during exposure were opened to inspect the crack surfaces for evidence of crack growth. The threshold stress intensity value, KEAC, is the highest applied stress intensity that produced neither a failure of the specimen during the exposure nor showed evidence of crack growth. The threshold stress intensity factor of the Ti 6Al-4V forged tank material when exposed to AF-M315E monopropellant was found to be at least 22.0 kilopounds per square inch. The stress intensity factor of the weld material was at least 31.3 kilopounds per square inch.

Nanomechanical characterization of nanostructured bainitic steel: Peak Force Microscopy and Nanoindentation with AFM.

Science.gov (United States)

Morales-Rivas, Lucia; González-Orive, Alejandro; Garcia-Mateo, Carlos; Hernández-Creus, Alberto; Caballero, Francisca G; Vázquez, Luis

2015-11-25

The full understanding of the deformation mechanisms in nanostructured bainite requires the local characterization of its mechanical properties, which are expected to change from one phase, bainitic ferrite, to another, austenite. This study becomes a challenging process due to the bainitic nanostructured nature and high Young's modulus. In this work, we have carried out such study by means of the combination of AFM-based techniques, such as nanoindentation and Peak Force Quantitative Nanomechanical Mapping (PF-QNM) measurements. We have addressed critically the limits and advantages of these techniques and been able to measure some elastoplastic parameters of both phases. Specifically, we have analyzed by PF-QNM two nanostructured bainitic steels, with a finer and a coarser structure, and found that both phases have a similar Young's modulus.

Beyond topography - enhanced imaging of cometary dust with the MIDAS AFM

Science.gov (United States)

Bentley, M. S.; Torkar, K.; Jeszenszky, H.; Romstedt, J.

2013-09-01

The MIDAS atomic force microscope (AFM) onboard the Rosetta spacecraft is primarily designed to return the 3D shape and structure of cometary dust particles collected at comet 67P/Churyumov-Gerasimenko [1]. Commercial AFMs have, however, been further developed to measure many other sample properties. The possibilities to make such measurements with MIDAS are explored here.

Binding behavior of CRP and anti-CRP antibody analyzed with SPR and AFM measurement

International Nuclear Information System (INIS)

Lee, Soo-Keun; Kim, Hyun-Chul; Cho, Sang-Joon; Jeong, Sang Won; Jeon, Won Bae

2008-01-01

Atomic force microscope (AFM) was exploited to take picture of the molecular topology of C-reactive protein (CRP) in phosphate-buffered saline (PBS) solution. An explicit molecular image of CRP demonstrated a pentagonal structure composed of five subunits. Dimensions of the doughnut-shaped CRP molecule measured by AFM were about 25 nm in outside diameter and 10 nm in central pore diameter, and the height of CRP molecule was about 4 nm which was comparable to the value determined by X-ray crystallography. Bis(N-succinimido)-11,11'-dithiobis (undecyl succinate) (DSNHS) was synthesized for use as a linker for immobilizing anti-CRP antibody (anti-CRP) onto the gold surface of a surface plasmon resonance (SPR) sensor chip. DSNHS formed self-assembled monolayer (SAM) on the gold surface. By use of an AFM tip, a pattern of ditch was engraved within the SAM of DSNHS, and anti-CRP was immobilized on the engraved SAM through replacement of N-hydroxysuccinimide group on the outside surface of DSNHS by the amine group of anti-CRP. Formation of CRP/anti-CRP complex on the gold surface of SPR sensor chip was clearly demonstrated by measuring SPR angle shift. A consecutive series of SAM, SAM/anti-CRP, and SAM/anti-CRP/CRP complexes was generated on a SPR sensor chip, and the changes in depth of the ditch were monitored by taking AFM images of the complexes. Comparative analysis of the depth differences indicates that binding of CRP to anti-CRP occurs in a planar mode

AFM tip characterization by using FFT filtered images of step structures

Energy Technology Data Exchange (ETDEWEB)

Yan, Yongda, E-mail: yanyongda@hit.edu.cn [Key Laboratory of Micro-systems and Micro-structures Manufacturing of Ministry of Education, Harbin Institute of Technology, Harbin, Heilongjiang 150001 (China); Center For Precision Engineering, Harbin Institute of Technology, Harbin, Heilongjiang 150001 (China); Xue, Bo [Key Laboratory of Micro-systems and Micro-structures Manufacturing of Ministry of Education, Harbin Institute of Technology, Harbin, Heilongjiang 150001 (China); Center For Precision Engineering, Harbin Institute of Technology, Harbin, Heilongjiang 150001 (China); Hu, Zhenjiang; Zhao, Xuesen [Center For Precision Engineering, Harbin Institute of Technology, Harbin, Heilongjiang 150001 (China)

2016-01-15

The measurement resolution of an atomic force microscope (AFM) is largely dependent on the radius of the tip. Meanwhile, when using AFM to study nanoscale surface properties, the value of the tip radius is needed in calculations. As such, estimation of the tip radius is important for analyzing results taken using an AFM. In this study, a geometrical model created by scanning a step structure with an AFM tip was developed. The tip was assumed to have a hemispherical cone shape. Profiles simulated by tips with different scanning radii were calculated by fast Fourier transform (FFT). By analyzing the influence of tip radius variation on the spectra of simulated profiles, it was found that low-frequency harmonics were more susceptible, and that the relationship between the tip radius and the low-frequency harmonic amplitude of the step structure varied monotonically. Based on this regularity, we developed a new method to characterize the radius of the hemispherical tip. The tip radii estimated with this approach were comparable to the results obtained using scanning electron microscope imaging and blind reconstruction methods. - Highlights: • The AFM tips with different radii were simulated to scan a nano-step structure. • The spectra of the simulation scans under different radii were analyzed. • The functions of tip radius and harmonic amplitude were used for evaluating tip. • The proposed method has been validated by SEM imaging and blind reconstruction.

Visualising the Micro World of Chemical/Geochemical Interactions Using Atomic Force Microscopy (AFM)

Energy Technology Data Exchange (ETDEWEB)

Graham, G M; Sorbie, K S

1997-12-31

Scanning force microscopy, in particular AFM (Atomic Force Microscopy), provides a particular useful and interesting tool for the examination of surface structure at the near-atomic level. AFM is particularly well suited to the study of interactions at the surface in aqueous solutions using real time in-situ measurements. In this paper there is presented AFM images showing in situ crystal growth from supersaturated BaSO{sub 4} solutions onto the surface of barite. Growth structures in the form of spiral crystal growth features, presumably originating from screw dislocations, are illustrated. AFM images of novel scale crystal growth inhibition experiments are presented. Examination of the manner in which generically different species adsorb onto growth structures may help to explain mechanistic differences in the way which different inhibitor species perform against barium sulphate scale formation. Adsorption of polyacrylamide species onto mica surfaces have been viewed. The general utility of AFM to a number of other common surface interactions in oil field chemistry will be discussed. 17 refs., 3 figs.

AFM-CMM integrated instrument user manual

DEFF Research Database (Denmark)

Marinello, Francesco; Bariani, Paolo

This manual gives general important guidelines for a proper use of the integrated AFM-CMM instrument. More information can be collected reading: • N. Kofod Ph.D thesis [1]; • P. Bariani Ph.D thesis [2]; • Dualscope DME 95-200 operation manuals [3]; • SPIP help [4] • Stitching software user manual...

Temperature-dependent imaging of living cells by AFM

International Nuclear Information System (INIS)

Espenel, Cedric; Giocondi, Marie-Cecile; Seantier, Bastien; Dosset, Patrice; Milhiet, Pierre-Emmanuel; Le Grimellec, Christian

2008-01-01

Characterization of lateral organization of plasma membranes is a prerequisite to the understanding of membrane structure-function relationships in living cells. Lipid-lipid and lipid-protein interactions are responsible for the existence of various membrane microdomains involved in cell signalization and in numerous pathologies. Developing approaches for characterizing microdomains associate identification tools like recognition imaging with high-resolution topographical imaging. Membrane properties are markedly dependent on temperature. However, mesoscopic scale topographical information of cell surface in a temperature range covering most of cell biology experimentation is still lacking. In this work we have examined the possibility of imaging the temperature-dependent behavior of eukaryotic cells by atomic force microscopy (AFM). Our results establish that the surface of living CV1 kidney cells can be imaged by AFM, between 5 and 37 deg. C, both in contact and tapping modes. These first temperature-dependent data show that large cell structures appeared essentially stable at a microscopic scale. On the other hand, as shown by contact mode AFM, the surface was highly dynamic at a mesoscopic scale, with marked changes in apparent topography, friction, and deflection signals. When keeping the scanning conditions constant, a progressive loss in the image contrast was however observed, using tapping mode, on decreasing the temperature

Ultra-large scale AFM of lipid droplet arrays: investigating the ink transfer volume in dip pen nanolithography

International Nuclear Information System (INIS)

Förste, Alexander; Pfirrmann, Marco; Sachs, Johannes; Gröger, Roland; Walheim, Stefan; Brinkmann, Falko; Hirtz, Michael; Fuchs, Harald; Schimmel, Thomas

2015-01-01

There are only few quantitative studies commenting on the writing process in dip-pen nanolithography with lipids. Lipids are important carrier ink molecules for the delivery of bio-functional patters in bio-nanotechnology. In order to better understand and control the writing process, more information on the transfer of lipid material from the tip to the substrate is needed. The dependence of the transferred ink volume on the dwell time of the tip on the substrate was investigated by topography measurements with an atomic force microscope (AFM) that is characterized by an ultra-large scan range of 800 × 800 μm 2 . For this purpose arrays of dots of the phospholipid1,2-dioleoyl-sn-glycero-3-phosphocholine were written onto planar glass substrates and the resulting pattern was imaged by large scan area AFM. Two writing regimes were identified, characterized of either a steady decline or a constant ink volume transfer per dot feature. For the steady state ink transfer, a linear relationship between the dwell time and the dot volume was determined, which is characterized by a flow rate of about 16 femtoliters per second. A dependence of the ink transport from the length of pauses before and in between writing the structures was observed and should be taken into account during pattern design when aiming at best writing homogeneity. The ultra-large scan range of the utilized AFM allowed for a simultaneous study of the entire preparation area of almost 1 mm 2 , yielding good statistic results. (paper)

Ultra-large scale AFM of lipid droplet arrays: investigating the ink transfer volume in dip pen nanolithography

Science.gov (United States)

Förste, Alexander; Pfirrmann, Marco; Sachs, Johannes; Gröger, Roland; Walheim, Stefan; Brinkmann, Falko; Hirtz, Michael; Fuchs, Harald; Schimmel, Thomas

2015-05-01

There are only few quantitative studies commenting on the writing process in dip-pen nanolithography with lipids. Lipids are important carrier ink molecules for the delivery of bio-functional patters in bio-nanotechnology. In order to better understand and control the writing process, more information on the transfer of lipid material from the tip to the substrate is needed. The dependence of the transferred ink volume on the dwell time of the tip on the substrate was investigated by topography measurements with an atomic force microscope (AFM) that is characterized by an ultra-large scan range of 800 × 800 μm2. For this purpose arrays of dots of the phospholipid1,2-dioleoyl-sn-glycero-3-phosphocholine were written onto planar glass substrates and the resulting pattern was imaged by large scan area AFM. Two writing regimes were identified, characterized of either a steady decline or a constant ink volume transfer per dot feature. For the steady state ink transfer, a linear relationship between the dwell time and the dot volume was determined, which is characterized by a flow rate of about 16 femtoliters per second. A dependence of the ink transport from the length of pauses before and in between writing the structures was observed and should be taken into account during pattern design when aiming at best writing homogeneity. The ultra-large scan range of the utilized AFM allowed for a simultaneous study of the entire preparation area of almost 1 mm2, yielding good statistic results.

Association between Urinary Aflatoxin (AFM1 and Dietary Intake among Adults in Hulu Langat District, Selangor, Malaysia

Directory of Open Access Journals (Sweden)

Siti Husna Sulaiman

2018-04-01

Full Text Available Aflatoxin is a food contaminant and its exposure through the diet is frequent and ubiquitous. A long-term dietary aflatoxin exposure has been linked to the development of liver cancer in populations with high prevalence of aflatoxin contamination in foods. Therefore, this study was conducted to identify the association between urinary aflatoxin M1 (AFM1, a biomarker of aflatoxin exposure, with the dietary intake among adults in Hulu Langat district, Selangor, Malaysia. Certain food products have higher potential for aflatoxin contamination and these were listed in a Food Frequency Questionnaire, which was given to all study participants. This allowed us to record consumption rates for each food product listed. Concomitantly, urine samples were collected, from adults in selected areas in Hulu Langat district, for the measurement of AFM1 levels using an ELISA kit. Of the 444 urine samples collected and tested, 199 were positive for AFM1, with 37 of them exceeding the limit of detection (LOD of 0.64 ng/mL. Cereal products showed the highest consumption level among all food groups, with an average intake of 512.54 g per day. Chi-square analysis showed that consumption of eggs (X2 = 4.77, p = 0.03 and dairy products (X2 = 19.36, p < 0.01 had significant associations with urinary AFM1 but both food groups were having a phi and Cramer’s V value that less than 0.3, which indicated that the association between these food groups’ consumption and AFM1 level in urine was weak.

Combination and Integration of Qualitative and Quantitative Analysis

Directory of Open Access Journals (Sweden)

Philipp Mayring

2001-02-01

Full Text Available In this paper, I am going to outline ways of combining qualitative and quantitative steps of analysis on five levels. On the technical level, programs for the computer-aided analysis of qualitative data offer various combinations. Where the data are concerned, the employment of categories (for instance by using qualitative content analysis allows for combining qualitative and quantitative forms of data analysis. On the individual level, the creation of types and the inductive generalisation of cases allow for proceeding from individual case material to quantitative generalisations. As for research design, different models can be distinguished (preliminary study, generalisation, elaboration, triangulation which combine qualitative and quantitative steps of analysis. Where the logic of research is concerned, it can be shown that an extended process model which combined qualitative and quantitative research can be appropriate and thus lead to an integration of the two approaches. URN: urn:nbn:de:0114-fqs010162

Joint Research on Scatterometry and AFM Wafer Metrology

Science.gov (United States)

Bodermann, Bernd; Buhr, Egbert; Danzebrink, Hans-Ulrich; Bär, Markus; Scholze, Frank; Krumrey, Michael; Wurm, Matthias; Klapetek, Petr; Hansen, Poul-Erik; Korpelainen, Virpi; van Veghel, Marijn; Yacoot, Andrew; Siitonen, Samuli; El Gawhary, Omar; Burger, Sven; Saastamoinen, Toni

2011-11-01

Supported by the European Commission and EURAMET, a consortium of 10 participants from national metrology institutes, universities and companies has started a joint research project with the aim of overcoming current challenges in optical scatterometry for traceable linewidth metrology. Both experimental and modelling methods will be enhanced and different methods will be compared with each other and with specially adapted atomic force microscopy (AFM) and scanning electron microscopy (SEM) measurement systems in measurement comparisons. Additionally novel methods for sophisticated data analysis will be developed and investigated to reach significant reductions of the measurement uncertainties in critical dimension (CD) metrology. One final goal will be the realisation of a wafer based reference standard material for calibration of scatterometers.

AFM plough YBCO micro bridges: substrate effects

CSIR Research Space (South Africa)

Elkaseh, A

2009-04-01

Full Text Available AFM nanolithography was used as a novel cutting technique to define micro-size YBCO superconducting constrictions. Researchers studied the substrate effects on MgO and STO substrates and showed that the observed Shapiro steps from the bridges on STO...

Analysis the effect of different geometries of AFM's cantilever on the dynamic behavior and the critical forces of three-dimensional manipulation

Energy Technology Data Exchange (ETDEWEB)

Korayem, Moharam Habibnejad, E-mail: hkorayem@iust.ac.ir; Saraie, Maniya B.; Saraee, Mahdieh B.

2017-04-15

An important challenge when using an atomic force microscope (AFM) is to be able to control the force exerted by the AFM for performing various tasks. Nevertheless, the exerted force is proportional to the deflection of the AFM cantilever, which itself is affected by a cantilever's stiffness coefficient. Many papers have been published so far on the methods of obtaining the stiffness coefficients of AFM cantilevers in 2D; however, a comprehensive model is yet to be presented on 3D cantilever motion. The discrepancies between the equations of the 2D and 3D analysis are due to the number and direction of forces and moments that are applied to a cantilever. Moreover, in the 3D analysis, contrary to the 2D analysis, due to the interaction between the forces and moments applied on a cantilever, its stiffness values cannot be separately expressed for each direction; and instead, a stiffness matrix should be used to correctly derive the relevant equations. In this paper, 3D stiffness coefficient matrices have been obtained for three common cantilever geometries including the rectangular, V-shape and dagger-shape cantilevers. The obtained equations are validated by two methods. In the first approach, the Finite Element Method is combined with the cantilever deflection values computed by using the obtained stiffness matrices. In the second approach, by reducing the problem's parameters, the forces applied on a cantilever along different directions are compared with each other in 2D and 3D cases. Then the 3D manipulation of a stiff nanoparticle is modeled and simulated by using the stiffness matrices obtained for the three cantilever geometries. The obtained results indicate that during the manipulation process, the dagger-shaped and rectangular cantilevers exert the maximum and minimum amounts of forces on the stiff nanoparticle, respectively. Also, by examining the effects of different probe tip geometries, it is realized that a probe tip of cylindrical geometry

Energy Dispersive Spectrometry and Quantitative Analysis Short Course. Introduction to X-ray Energy Dispersive Spectrometry and Quantitative Analysis

Science.gov (United States)

Carpenter, Paul; Curreri, Peter A. (Technical Monitor)

2002-01-01

This course will cover practical applications of the energy-dispersive spectrometer (EDS) to x-ray microanalysis. Topics covered will include detector technology, advances in pulse processing, resolution and performance monitoring, detector modeling, peak deconvolution and fitting, qualitative and quantitative analysis, compositional mapping, and standards. An emphasis will be placed on use of the EDS for quantitative analysis, with discussion of typical problems encountered in the analysis of a wide range of materials and sample geometries.

Application of Contact Mode AFM to Manufacturing Processes

Science.gov (United States)

Giordano, Michael A.; Schmid, Steven R.

A review of the application of contact mode atomic force microscopy (AFM) to manufacturing processes is presented. A brief introduction to common experimental techniques including hardness, scratch, and wear testing is presented, with a discussion of challenges in the extension of manufacturing scale investigations to the AFM. Differences between the macro- and nanoscales tests are discussed, including indentation size effects and their importance in the simulation of processes such as grinding. The basics of lubrication theory are presented and friction force microscopy is introduced as a method of investigating metal forming lubrication on the nano- and microscales that directly simulates tooling/workpiece asperity interactions. These concepts are followed by a discussion of their application to macroscale industrial manufacturing processes and direct correlations are made.

Inspection, visualisation and analysis of quantitative proteomics data

OpenAIRE

Gatto, Laurent

2016-01-01

Material Quantitative Proteomics and Data Analysis Course. 4 - 5 April 2016, Queen Hotel, Chester, UK Table D - Inspection, visualisation and analysis of quantitative proteomics data, Laurent Gatto (University of Cambridge)

Quantitative Moessbauer analysis

International Nuclear Information System (INIS)

Collins, R.L.

1978-01-01

The quantitative analysis of Moessbauer data, as in the measurement of Fe 3+ /Fe 2+ concentration, has not been possible because of the different mean square velocities (x 2 ) of Moessbauer nuclei at chemically different sites. A method is now described which, based on Moessbauer data at several temperatures, permits the comparison of absorption areas at (x 2 )=0. (Auth.)

AFM Study of Structure Influence on Butterfly Wings Coloration

Directory of Open Access Journals (Sweden)

Dinara Sultanovna Dallaeva

2012-01-01

Full Text Available This study describes the structural coloration of the butterfly Vanessa Atalanta wings and shows how the atomic force microscopy (AFM can be applied to the study of wings morphology and wings surface behavior under the temperature. The role of the wings morphology in colors was investigated. Different colors of wings have different topology and can be identified by them. AFM in semi-contact mode was used to study the wings surface. The wing surface area, which is close to the butterfly body, has shiny brown color and the peak of surface roughness is about 600 nm. The changing of morphology at different temperatures is shown.

Systematic UHV-AFM experiments on Na nano-particles and nano-structures in NaCl

OpenAIRE

Sugonyako, A.V.; Turkin, A.A.; Gaynutdinov, R.; Vainshtein, D.I.; Hartog, H.W. den; Bukharaev, A.A.

2005-01-01

Results of systematic AFM (atomic force microscopy) experiments on heavily and moderatly irradiated NaCl samples are presented. The sodium nanoparticles and structures of nanoparticles are poduced in sodium chloride during irradiation. The AFM images of the nanoparticles have been obtained in ultra high vacuum (UHV) in the non-contact mode with an Omicron UHV AFM/STM system. The sizes and arrangements of the observed particles depend on the irradiation conditions. The melting behaviour of the...

Quantitative Data Analysis--In the Graduate Curriculum

Science.gov (United States)

Albers, Michael J.

2017-01-01

A quantitative research study collects numerical data that must be analyzed to help draw the study's conclusions. Teaching quantitative data analysis is not teaching number crunching, but teaching a way of critical thinking for how to analyze the data. The goal of data analysis is to reveal the underlying patterns, trends, and relationships of a…

Localized Quantitative Characterization of Chemical Functionalization Effects on Adhesion Properties of SWNT

Directory of Open Access Journals (Sweden)

Hao Lu

2011-01-01

Full Text Available Chemical modification of single-walled carbon nanotubes (SWNT has been found to be an excellent method to promote SWNT dispersion, and possibly to improve interaction with matrices via covalent bonding. It is thus a quite promising technique to enhance the mechanical properties of SWNT-reinforced nanocomposites. However, the underlying mechanism of SWNT chemical functionalization effects on interfacial strength is not quantitatively understood, limiting their usefulness in the design of nanocomposites. In this work, an atomic force microscopy (AFM- based adhesive force mapping technique combined with a statistical analysis method were developed and implemented to study adhesive interactions of small SWNT bundles functionalized by amino, epoxide, and hydroperoxide groups as compared to SDS-treated SWNT in controlled environment. Finally, the importance of such localized quantitative measurements in SWNT-reinforced nanocomposites design and fabrication was also discussed.

Charge storage in mesoscopic graphitic islands fabricated using AFM bias lithography

Energy Technology Data Exchange (ETDEWEB)

Kurra, Narendra; Basavaraja, S; Kulkarni, G U [Chemistry and Physics of Materials Unit and DST Unit on Nanoscience, Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur PO, Bangalore 560 064 (India); Prakash, Gyan; Fisher, Timothy S; Reifenberger, Ronald G, E-mail: kulkarni@jncasr.ac.in, E-mail: reifenbr@purdue.edu [Birck Nanotechnology Center, Purdue University, West Lafayette, IN 47907 (United States)

2011-06-17

Electrochemical oxidation and etching of highly oriented pyrolytic graphite (HOPG) has been achieved using biased atomic force microscopy (AFM) lithography, allowing patterns of varying complexity to be written into the top layers of HOPG. The graphitic oxidation process and the trench geometry after writing were monitored using intermittent contact mode AFM. Electrostatic force microscopy reveals that the isolated mesoscopic islands formed during the AFM lithography process become positively charged, suggesting that they are laterally isolated from the surrounding HOPG substrate. The electrical transport studies of these laterally isolated finite-layer graphitic islands enable detailed characterization of electrical conduction along the c-direction and reveal an unexpected stability of the charged state. Utilizing conducting-atomic force microscopy, the measured I(V) characteristics revealed significant non-linearities. Micro-Raman studies confirm the presence of oxy functional groups formed during the lithography process.

Finite element modeling of trolling-mode AFM.

Science.gov (United States)

Sajjadi, Mohammadreza; Pishkenari, Hossein Nejat; Vossoughi, Gholamreza

2018-06-01

Trolling mode atomic force microscopy (TR-AFM) has overcome many imaging problems in liquid environments by considerably reducing the liquid-resonator interaction forces. The finite element model of the TR-AFM resonator considering the effects of fluid and nanoneedle flexibility is presented in this research, for the first time. The model is verified by ABAQUS software. The effect of installation angle of the microbeam relative to the horizon and the effect of fluid on the system behavior are investigated. Using the finite element model, frequency response curve of the system is obtained and validated around the frequency of the operating mode by the available experimental results, in air and liquid. The changes in the natural frequencies in the presence of liquid are studied. The effects of tip-sample interaction on the excitation of higher order modes of the system are also investigated in air and liquid environments. Copyright © 2018 Elsevier B.V. All rights reserved.

Original methods of quantitative analysis developed for diverse samples in various research fields. Quantitative analysis at NMCC

International Nuclear Information System (INIS)

Sera, Koichiro

2003-01-01

Nishina Memorial Cyclotron Center (NMCC) has been opened for nationwide-common utilization of positron nuclear medicine (PET) and PIXE since April 1993. At the present time, nearly 40 subjects of PIXE in various research fields are pursued here, and more than 50,000 samples have been analyzed up to the present. In order to perform quantitative analyses of diverse samples, technical developments in sample preparation, measurement and data analysis have been continuously carried out. Especially, a standard-free method for quantitative analysis'' made it possible to perform analysis of infinitesimal samples, powdered samples and untreated bio samples, which could not be well analyzed quantitatively in the past. The standard-free method'' and a ''powdered internal standard method'' made the process for target preparation quite easier. It has been confirmed that results obtained by these methods show satisfactory accuracy and reproducibility preventing any ambiguity coming from complicated target preparation processes. (author)

Piezoelectric tuning fork biosensors for the quantitative measurement of biomolecular interactions

International Nuclear Information System (INIS)

Gonzalez, Laura; Maria Benito, Angel; Puig-Vidal, Manel; Otero, Jorge; Rodrigues, Mafalda; Pérez-García, Lluïsa

2015-01-01

The quantitative measurement of biomolecular interactions is of great interest in molecular biology. Atomic force microscopy (AFM) has proved its capacity to act as a biosensor and determine the affinity between biomolecules of interest. Nevertheless, the detection scheme presents certain limitations when it comes to developing a compact biosensor. Recently, piezoelectric quartz tuning forks (QTFs) have been used as laser-free detection sensors for AFM. However, only a few studies along these lines have considered soft biological samples, and even fewer constitute quantified molecular recognition experiments. Here, we demonstrate the capacity of QTF probes to perform specific interaction measurements between biotin–streptavidin complexes in buffer solution. We propose in this paper a variant of dynamic force spectroscopy based on representing adhesion energies E (aJ) against pulling rates v (nm s"–"1). Our results are compared with conventional AFM measurements and show the great potential of these sensors in molecular interaction studies. (paper)

Electrospray deposition from fountain pen AFM probes

NARCIS (Netherlands)

Geerlings, J.; Sarajlic, Edin; Berenschot, Johan W.; Abelmann, Leon; Tas, Niels Roelof

2012-01-01

In this paper we present for the first time electrospraying from fountain pen probes. By using electrospray contactless deposition in an AFM setup becomes possible. Experiments on a dedicated setup were carried out as first step towards this goal. Spraying from 8 and 2 µm apertures was observed. For

Fast and controlled fabrication of porous graphene oxide: application of AFM tapping for mechano-chemistry

Science.gov (United States)

Chu, Liangyong; Korobko, Alexander V.; Bus, Marcel; Boshuizen, Bart; Sudhölter, Ernst J. R.; Besseling, Nicolaas A. M.

2018-05-01

This paper describes a novel method to fabricate porous graphene oxide (PGO) from GO by exposure to oxygen plasma. Compared to other methods to fabricate PGO described so far, e.g. the thermal and steam etching methods, oxygen plasma etching method is much faster. We studied the development of the porosity with exposure time using atomic force microscopy (AFM). It was found that the development of PGO upon oxygen-plasma exposure can be controlled by tapping mode AFM scanning using a Si tip. AFM tapping stalls the growth of pores upon further plasma exposure at a level that coincides with the fraction of sp2 carbons in the GO starting material. We suggest that AFM tapping procedure changes the bond structure of the intermediate PGO structure, and these stabilized PGO structures cannot be further etched by oxygen plasma. This constitutes the first report of tapping AFM as a tool for local mechano-chemistry.

AFM of metallic nano-particles and nano-structures in heavily irradiated NaCl

NARCIS (Netherlands)

Gaynutdinov, R; Vainshtein, DI; Hak, SJ; Tolstikhina, A; Den Hartog, HW

2003-01-01

AFM investigations are reported for heavily, electron irradiated NaCl crystals in ultra high vacuum (UHV) in the non-contact mode-with an UHV AFM/STM Omicron system. To avoid chemical reactions between the radiolytic Na and oxygen and water, the irradiated samples were cleaved and prepared for the

Evaluation of defect density by top-view large scale AFM on metamorphic structures grown by MOVPE

Energy Technology Data Exchange (ETDEWEB)

Gocalinska, Agnieszka, E-mail: agnieszka.gocalinska@tyndall.ie; Manganaro, Marina; Dimastrodonato, Valeria; Pelucchi, Emanuele

2015-09-15

Highlights: • Metamorphic buffer layers of In{sub x}Ga{sub 1−x}As were grown by MOVPE and characterised by AFM and TEM. • It was found that AFM provides sufficient information to estimate threading defect density in metamorphic structures, even when significant roughness is present. • When planar-view TEM is lacking, a combination of cross-sectional TEM and large scale AFM can provide good evaluation of the material quality. • It is fast, cheap and non-destructive – can be very useful in development process of complicated structures, requiring multiple test growths and characterisation. - Abstract: We demonstrate an atomic force microscopy based method for estimation of defect density by identification of threading dislocations on a non-flat surface resulting from metamorphic growth. The discussed technique can be applied as an everyday evaluation tool for the quality of epitaxial structures and allow for cost reduction, as it lessens the amount of the transmission electron microscopy analysis required at the early stages of projects. Metamorphic structures with low surface defectivities (below 10{sup 6}) were developed successfully with the application of the technique, proving its usefulness in process optimisation.

Superparamagnetism in AFM Cr2O3 nanoparticles

International Nuclear Information System (INIS)

Tobia, D.; Winkler, E.L.; Zysler, R.D.; Granada, M.; Troiani, H.E.

2010-01-01

In this work we report the size effects on the magnetic properties of AFM Cr 2 O 3 nanoparticles. From transmission electron microscopy we determined that the system presents high crystallinity and narrow lognormal size distribution centred at = 7.8 nm with σ = 0.3. The magnetic properties of the nanoparticles were studied by magnetization and electron paramagnetic resonance (EPR) experiments. By EPR spectroscopy we established that the AFM order temperature, T N , shifted to ∼270 K when the size is reduced (T N (Bulk) ∼ 308 K). From the zero-field-cooling and the field-cooling magnetization curves we determined the blocking temperature T B = 28 K. Below T B the system presents exchange bias effect. We discuss the results by using recent models in terms of the internal magnetic structures of the nanoparticles.

Comparison of different aminofunctionalization strategies for attachment of single antibodies to AFM cantilevers

Energy Technology Data Exchange (ETDEWEB)

Ebner, Andreas [Institute of Biophysics, University of Linz, 4040 Linz (Austria)], E-mail: andreas.ebner@jku.at; Hinterdorfer, Peter; Gruber, Hermann J. [Institute of Biophysics, University of Linz, 4040 Linz (Austria)

2007-10-15

Atomic force microscopy (AFM) has developed into a key technique for elucidation of biological systems on the single molecular level. In particular, molecular recognition force microscopy has proven to be a powerful tool for the investigation of biological interactions under near physiological conditions. For this purpose, ligands are tethered to AFM tips and the interaction forces with cognate receptors on the sample surface are measured with pico-Newton accuracy. In the first step of tip functionalization, amino groups are typically introduced on the initially inert AFM tip. Several methods have been developed to reproducibly adjust the desired low density of amino groups on the tip surface, i.e. esterification with ethanolamine, gas-phase silanization with aminopropyl-triethoxysilane (APTES), or treatment with aminophenyl-trimethoxysilane (APhS) in toluene solution. In the present study, the usefulness of these methods for attachments of antibodies to AFM tips was characterized by a standardized test system, in which biotinylated IgG was bound to the tip and a dense monolayer of avidin on mica served as test sample. All three methods of aminofunctionalization were found fully satisfactory for attachment of single antibodies to AFM tips, only in a parallel macroscopic assay on silicon nitride chips a minor difference was found in that APTES appeared to yield a slightly lower surface density of amino groups.

Immobilizing live Escherichia coli for AFM studies of surface dynamics

International Nuclear Information System (INIS)

Lonergan, N.E.; Britt, L.D.; Sullivan, C.J.

2014-01-01

Atomic force microscopy (AFM) is a probe-based technique that permits high resolution imaging of live bacterial cells. However, stably immobilizing cells to withstand the probe-based lateral forces remains an obstacle in AFM mediated studies, especially those of live, rod shaped bacteria in nutrient media. Consequently, AFM has been under-utilized in the research of bacterial surface dynamics. The aim of the current study was to immobilize a less adherent Escherichia coli strain in a method that both facilitates AFM imaging in nutrient broth and preserves overall cell viability. Immobilization reagents and buffers were systematically evaluated and the cell membrane integrity was monitored in all sample preparations. As expected, the biocompatible gelatin coated surfaces facilitated stable cell attachment in lower ionic strength buffers, yet poorly immobilized cells in higher ionic strength buffers. In comparison, poly-L-lysine surfaces bound cells in both low and high ionic strength buffers. The benefit of the poly-L-lysine binding capacity was offset by the compromised membrane integrity exhibited by cells on poly-L-lysine surfaces. However, the addition of divalent cations and glucose to the immobilization buffer was found to mitigate this unfavorable effect. Ultimately, immobilization of E. coli cells on poly-L-lysine surfaces in a lower ionic strength buffer supplemented with Mg 2+ and Ca 2+ was determined to provide optimal cell attachment without compromising the overall cell viability. Cells immobilized in this method were stably imaged in media through multiple division cycles. Furthermore, permeability assays indicated that E. coli cells recover from the hypoosmotic stress caused by immobilization in low ionic strength buffers. Taken together, this data suggests that stable immobilization of viable cells on poly-L-lysine surfaces can be accomplished in lower ionic strength buffers that are supplemented with divalent cations for membrane stabilization while

Influence of the tip mass and position on the AFM cantilever dynamics: Coupling between bending, torsion and flexural modes

Energy Technology Data Exchange (ETDEWEB)

Mokhtari-Nezhad, F. [Department of Mechanical Engineering, Shahid Bahonar University of Kerman, Kerman (Iran, Islamic Republic of); Saidi, A.R., E-mail: saidi@mail.uk.ac.ir [Department of Mechanical Engineering, Shahid Bahonar University of Kerman, Kerman (Iran, Islamic Republic of); Ziaei-Rad, S. [Department of Mechanical Engineering, Isfahan University of Technology (IUT), Isfahan 84156-83111 (Iran, Islamic Republic of)

2009-08-15

The effects of the geometrical asymmetric related to tip position as a concentrated mass, on the sensitivity of all three vibration modes, lateral excitation (LE), torsional resonance (TR) and vertical excitation (VE), of an atomic force microscopy (AFM) microcantilever have been analyzed. The effects of the tip mass and its position are studied to report the novel results to estimating the vibration behavior of AFM such as resonance frequency and amplitude of the microcantilever. In this way, to achieve more accurate results, the coupled motion in all three modes is considered. In particular, it is investigated that performing the coupled motion in analysis of AFM microcantilever is almost necessary. It is shown that the tip mass and its position have significant effects on vibrational responses. The results show that considering the tip mass decreases the resonance frequencies particularly on high-order modes. However, dislocating of tip position has an inverse effect that causes an increase in the resonance frequencies. In addition, it has been shown that the amplitude of the AFM microcantilever is affected by the influences of tip and its position. These effects are caused by the interaction between flexural and torsional motion due to the moment of inertia of the tip mass.

Influence of the tip mass and position on the AFM cantilever dynamics: Coupling between bending, torsion and flexural modes

International Nuclear Information System (INIS)

Mokhtari-Nezhad, F.; Saidi, A.R.; Ziaei-Rad, S.

2009-01-01

The effects of the geometrical asymmetric related to tip position as a concentrated mass, on the sensitivity of all three vibration modes, lateral excitation (LE), torsional resonance (TR) and vertical excitation (VE), of an atomic force microscopy (AFM) microcantilever have been analyzed. The effects of the tip mass and its position are studied to report the novel results to estimating the vibration behavior of AFM such as resonance frequency and amplitude of the microcantilever. In this way, to achieve more accurate results, the coupled motion in all three modes is considered. In particular, it is investigated that performing the coupled motion in analysis of AFM microcantilever is almost necessary. It is shown that the tip mass and its position have significant effects on vibrational responses. The results show that considering the tip mass decreases the resonance frequencies particularly on high-order modes. However, dislocating of tip position has an inverse effect that causes an increase in the resonance frequencies. In addition, it has been shown that the amplitude of the AFM microcantilever is affected by the influences of tip and its position. These effects are caused by the interaction between flexural and torsional motion due to the moment of inertia of the tip mass.

Association between Urinary Aflatoxin (AFM1) and Dietary Intake among Adults in Hulu Langat District, Selangor, Malaysia

Science.gov (United States)

Sulaiman, Siti Husna

2018-01-01

Aflatoxin is a food contaminant and its exposure through the diet is frequent and ubiquitous. A long-term dietary aflatoxin exposure has been linked to the development of liver cancer in populations with high prevalence of aflatoxin contamination in foods. Therefore, this study was conducted to identify the association between urinary aflatoxin M1 (AFM1), a biomarker of aflatoxin exposure, with the dietary intake among adults in Hulu Langat district, Selangor, Malaysia. Certain food products have higher potential for aflatoxin contamination and these were listed in a Food Frequency Questionnaire, which was given to all study participants. This allowed us to record consumption rates for each food product listed. Concomitantly, urine samples were collected, from adults in selected areas in Hulu Langat district, for the measurement of AFM1 levels using an ELISA kit. Of the 444 urine samples collected and tested, 199 were positive for AFM1, with 37 of them exceeding the limit of detection (LOD) of 0.64 ng/mL. Cereal products showed the highest consumption level among all food groups, with an average intake of 512.54 g per day. Chi-square analysis showed that consumption of eggs (X2 = 4.77, p = 0.03) and dairy products (X2 = 19.36, p food groups were having a phi and Cramer’s V value that less than 0.3, which indicated that the association between these food groups’ consumption and AFM1 level in urine was weak. PMID:29642443

AFM characterization of nonwoven material functionalized by ZnO sputter coating

International Nuclear Information System (INIS)

Deng Bingyao; Yan Xiong; Wei Qufu; Gao Weidong

2007-01-01

Sputter coatings provide new approaches to the surface functionalization of textile materials. In this study, polyethylene terephthalate (PET) nonwoven material was used as a substrate for creating functional nanostructures on the fiber surfaces. A magnetron sputter coating was used to deposit functional zinc oxide (ZnO) nanostructures onto the nonwoven substrate. The evolution of the surface morphology of the fibers in the nonwoven web was examined using atomic force microscopy (AFM). The AFM observations revealed a significant difference in the morphology of the fibers before and after the sputter coating. The AFM images also indicated the effect of the sputtering conditions on the surface morphology of the fibers. The increase in the sputtering time led to the growth of the ZnO grains on the fiber surfaces. The higher pressure in the sputtering chamber could cause the formation of larger grains on the fiber surfaces. The higher power used also generated larger grains on the fiber surfaces

The Use of Atomic Force Microscopy for 3D Analysis of Nucleic Acid Hybridization on Microarrays.

Science.gov (United States)

Dubrovin, E V; Presnova, G V; Rubtsova, M Yu; Egorov, A M; Grigorenko, V G; Yaminsky, I V

2015-01-01

Oligonucleotide microarrays are considered today to be one of the most efficient methods of gene diagnostics. The capability of atomic force microscopy (AFM) to characterize the three-dimensional morphology of single molecules on a surface allows one to use it as an effective tool for the 3D analysis of a microarray for the detection of nucleic acids. The high resolution of AFM offers ways to decrease the detection threshold of target DNA and increase the signal-to-noise ratio. In this work, we suggest an approach to the evaluation of the results of hybridization of gold nanoparticle-labeled nucleic acids on silicon microarrays based on an AFM analysis of the surface both in air and in liquid which takes into account of their three-dimensional structure. We suggest a quantitative measure of the hybridization results which is based on the fraction of the surface area occupied by the nanoparticles.

Quantitative analysis of untreated bio-samples

International Nuclear Information System (INIS)

Sera, K.; Futatsugawa, S.; Matsuda, K.

1999-01-01

A standard-free method of quantitative analysis for untreated samples has been developed. For hair samples, measurements were performed by irradiating with a proton beam a few hairs as they are, and quantitative analysis was carried out by means of a standard-free method developed by ourselves. First, quantitative values of concentration of zinc were derived, then concentration of other elements was obtained by regarding zinc as an internal standard. As the result, values of concentration of sulphur for 40 samples agree well with the average value for a typical Japanese and also with each other within 20%, and validity of the present method could be confirmed. Accuracy was confirmed by comparing the results with those obtained by the usual internal standard method, too. For the purpose of a surface analysis of a bone sample, a very small incidence angle of the proton beam was used, so that both energy loss of the projectile and self-absorption of X-rays become negligible. As the result, consistent values of concentration for many elements were obtained by the standard-free method

Systematic UHV-AFM experiments on Na nano-particles and nano-structures in NaCl

NARCIS (Netherlands)

Sugonyako, A.V.; Turkin, A.A.; Gaynutdinov, R.; Vainshtein, D.I.; Hartog, H.W. den; Bukharaev, A.A.

2005-01-01

Results of systematic AFM (atomic force microscopy) experiments on heavily and moderatly irradiated NaCl samples are presented. The sodium nanoparticles and structures of nanoparticles are poduced in sodium chloride during irradiation. The AFM images of the nanoparticles have been obtained in ultra

Quantitative analysis of boron by neutron radiography

International Nuclear Information System (INIS)

Bayuelken, A.; Boeck, H.; Schachner, H.; Buchberger, T.

1990-01-01

The quantitative determination of boron in ores is a long process with chemical analysis techniques. As nuclear techniques like X-ray fluorescence and activation analysis are not applicable for boron, only the neutron radiography technique, using the high neutron absorption cross section of this element, can be applied for quantitative determinations. This paper describes preliminary tests and calibration experiments carried out at a 250 kW TRIGA reactor. (orig.) [de

AFM cantilever with in situ renewable mercury microelectrode

NARCIS (Netherlands)

Schön, Peter Manfred; Geerlings, J.; Tas, Niels Roelof; Sarajlic, Edin

2013-01-01

We report here first results obtained on a novel, in situ renewable mercury microelectrode integrated into an atomic force microscopy (AFM) cantilever. Our approach is based on a fountain pen probe with appropriate dimensions enabling reversible filling with(nonwetting) mercury under changing the

FRAME (Force Review Automation Environment): MATLAB-based AFM data processor.

Science.gov (United States)

Partola, Kostyantyn R; Lykotrafitis, George

2016-05-03

Data processing of force-displacement curves generated by atomic force microscopes (AFMs) for elastic moduli and unbinding event measurements is very time consuming and susceptible to user error or bias. There is an evident need for consistent, dependable, and easy-to-use AFM data processing software. We have developed an open-source software application, the force review automation environment (or FRAME), that provides users with an intuitive graphical user interface, automating data processing, and tools for expediting manual processing. We did not observe a significant difference between manually processed and automatically processed results from the same data sets. Copyright © 2016 Elsevier Ltd. All rights reserved.

Ultra-high aspect ratio replaceable AFM tips using deformation-suppressed focused ion beam milling

DEFF Research Database (Denmark)

Savenko, Alexey; Yildiz, Izzet; Petersen, Dirch Hjorth

2013-01-01

Fabrication of ultra-high aspect ratio exchangeable and customizable tips for atomic force microscopy (AFM) using lateral focused ion beam (FIB) milling is presented. While on-axis FIB milling does allow high aspect ratio (HAR) AFM tips to be defined, lateral milling gives far better flexibility...

Optimization of Easy Atomic Force Microscope (ezAFM) Controls for Semiconductor Nanostructure Profiling

Science.gov (United States)

2017-09-01

ARL-MR-0965 ● SEP 2017 US Army Research Laboratory Optimization of Easy Atomic Force Microscope (ezAFM) Controls for... Optimization of Easy Atomic Force Microscope (ezAFM) Controls for Semiconductor Nanostructure Profiling by Satwik Bisoi Science and...REPORT TYPE Memorandum Report 3. DATES COVERED (From - To) 2017 July 05–2017 August 18 4. TITLE AND SUBTITLE Optimization of Easy Atomic Force

Quantitative image analysis of synovial tissue

NARCIS (Netherlands)

van der Hall, Pascal O.; Kraan, Maarten C.; Tak, Paul Peter

2007-01-01

Quantitative image analysis is a form of imaging that includes microscopic histological quantification, video microscopy, image analysis, and image processing. Hallmarks are the generation of reliable, reproducible, and efficient measurements via strict calibration and step-by-step control of the

Quantitative Auger analysis of Nb-Ge superconducting alloys

International Nuclear Information System (INIS)

Buitrago, R.H.

1980-01-01

The feasibility of using Auger electron analysis for quantitative analysis was investigated by studying Nb 3 Ge thin-film Auger data with different approaches. A method base on elemental standards gave consistent quantitative values with reported Nb-Ge data. Alloy sputter yields were also calculated and results were consistent with those for pure elements

Tip-enhanced Raman mapping with top-illumination AFM.

Science.gov (United States)

Chan, K L Andrew; Kazarian, Sergei G

2011-04-29

Tip-enhanced Raman mapping is a powerful, emerging technique that offers rich chemical information and high spatial resolution. Currently, most of the successes in tip-enhanced Raman scattering (TERS) measurements are based on the inverted configuration where tips and laser are approaching the sample from opposite sides. This results in the limitation of measurement for transparent samples only. Several approaches have been developed to obtain tip-enhanced Raman mapping in reflection mode, many of which involve certain customisations of the system. We have demonstrated in this work that it is also possible to obtain TERS nano-images using an upright microscope (top-illumination) with a gold-coated Si atomic force microscope (AFM) cantilever without significant modification to the existing integrated AFM/Raman system. A TERS image of a single-walled carbon nanotube has been achieved with a spatial resolution of ∼ 20-50 nm, demonstrating the potential of this technique for studying non-transparent nanoscale materials.

Tip-enhanced Raman mapping with top-illumination AFM

Energy Technology Data Exchange (ETDEWEB)

Chan, K L Andrew; Kazarian, Sergei G, E-mail: s.kazarian@imperial.ac.uk [Department of Chemical Engineering, Imperial College London, SW7 2AZ (United Kingdom)

2011-04-29

Tip-enhanced Raman mapping is a powerful, emerging technique that offers rich chemical information and high spatial resolution. Currently, most of the successes in tip-enhanced Raman scattering (TERS) measurements are based on the inverted configuration where tips and laser are approaching the sample from opposite sides. This results in the limitation of measurement for transparent samples only. Several approaches have been developed to obtain tip-enhanced Raman mapping in reflection mode, many of which involve certain customisations of the system. We have demonstrated in this work that it is also possible to obtain TERS nano-images using an upright microscope (top-illumination) with a gold-coated Si atomic force microscope (AFM) cantilever without significant modification to the existing integrated AFM/Raman system. A TERS image of a single-walled carbon nanotube has been achieved with a spatial resolution of {approx} 20-50 nm, demonstrating the potential of this technique for studying non-transparent nanoscale materials.

Tip-enhanced Raman mapping with top-illumination AFM

International Nuclear Information System (INIS)

Chan, K L Andrew; Kazarian, Sergei G

2011-01-01

Tip-enhanced Raman mapping is a powerful, emerging technique that offers rich chemical information and high spatial resolution. Currently, most of the successes in tip-enhanced Raman scattering (TERS) measurements are based on the inverted configuration where tips and laser are approaching the sample from opposite sides. This results in the limitation of measurement for transparent samples only. Several approaches have been developed to obtain tip-enhanced Raman mapping in reflection mode, many of which involve certain customisations of the system. We have demonstrated in this work that it is also possible to obtain TERS nano-images using an upright microscope (top-illumination) with a gold-coated Si atomic force microscope (AFM) cantilever without significant modification to the existing integrated AFM/Raman system. A TERS image of a single-walled carbon nanotube has been achieved with a spatial resolution of ∼ 20-50 nm, demonstrating the potential of this technique for studying non-transparent nanoscale materials.

Topographical heterogeneity in transparent PVA hydrogels studied by AFM

Energy Technology Data Exchange (ETDEWEB)

Pramanick, Ashit Kumar; Gupta, Siddhi, E-mail: siddhigupta@nmlindia.org; Mishra, Trilochan; Sinha, Arvind

2012-02-01

Physically crosslinked poly (vinyl alcohol) (PVA) hydrogels have a wide range of biomedical applications. Transparent and stable PVA hydrogels synthesized by freeze-thawing method are potential candidates to be used as tissue engineering scaffolds provided they exhibit suitable topographical roughness and surface energy. The effect of processing parameters i.e., polymer concentration and number of freeze-thaw cycles on the resulting topography of the freeze-thawed transparent hydrogels has been studied and quantified using non-contact mode of an atomic force microscope (AFM) and image analysis. Simultaneously captured phase contrast images have revealed significant information about morphological changes in the topographical features and crystallinity of the hydrogels. Topographical roughness was found to decrease as a function of number of freeze-thaw cycles.

The influence of aminophylline on the nanostructure and nanomechanics of T lymphocytes: an AFM study

Science.gov (United States)

Huang, Xun; He, Jiexiang; Liu, Mingxian; Zhou, Changren

2014-09-01

Although much progress has been made in the illustration of the mechanism of aminophylline (AM) treating asthma, there is no data about its effect on the nanostructure and nanomechanics of T lymphocytes. Here, we presented atomic force spectroscopy (AFM)-based investigations at the nanoscale level to address the above fundamental biophysical questions. As increasing AM treatment time, T lymphocytes' volume nearly double increased and then decreased. The changes of nanostructural features of the cell membrane, i.e., mean height of particles, root-mean-square roughness (Rq), crack and fragment appearance, increased with AM treatment time. T lymphocytes were completely destroyed with 96-h treatment, and they existed in the form of small fragments. Analysis of force-distance curves showed that the adhesion force of cell surface decreased significantly with the increase of AM treatment time, while the cell stiffness increased firstly and then decreased. These changes were closely correlated to the characteristics and process of cell oncosis. In total, these quantitative and qualitative changes of T lymphocytes' structure and nanomechanical properties suggested that AM could induce T lymphocyte oncosis to exert anti-inflammatory effects for treating asthma. These findings provide new insights into the T lymphocyte oncosis and the anti-inflammatory mechanism and immune regulation actions of AM.

AFM-based force spectroscopy measurements of mature amyloid fibrils of the peptide glucagon

DEFF Research Database (Denmark)

Dong, M. D.; Hovgaard, M. B.; Mamdouh, W.

2008-01-01

We report on the mechanical characterization of individual mature amyloid fibrils by atomic force microscopy (AFM) and AFM-based single-molecule force spectroscopy (SMFS). These self-assembling materials, formed from the 29-residue amphiphatic peptide hormone glucagon, were found to display...... a reversible elastic behaviour. Based on AFM morphology and SMFS studies, we suggest that the observed elasticity is due to a force-induced conformational transition which is reversible due to the beta-helical conformation of protofibrils, allowing a high degree of extension. The elastic properties...... of such mature fibrils contribute to their high stability, suggesting that the internal hydrophobic interactions of amyloid fibrils are likely to be of fundamental importance in the assembly of amyloid fibrils and therefore for the understanding of the progression of their associated pathogenic disorders...

Feasibility of multi-walled carbon nanotube probes in AFM anodization lithography

International Nuclear Information System (INIS)

Choi, Ji Sun; Bae, Sukjong; Ahn, Sang Jung; Kim, Dal Hyun; Jung, Ki Young; Han, Cheolsu; Chung, Chung Choo; Lee, Haiwon

2007-01-01

Multi-walled carbon nanotube (CNT) tips were used in atomic force microscope (AFM) anodization lithography to investigate their advantages over conventional tips. The CNT tip required a larger threshold voltage than the mother silicon tip due to the Schottky barrier at the CNT-Si interface. Current-to-voltage curves distinguished the junction property between CNTs and mother tips. The CNT-platinum tip, which is more conductive than the CNT-silicon tip, showed promising results for AFM anodization lithography. Finally, the nanostructures with high aspect ratio were fabricated using a pulsed bias voltage technique as well as the CNT tip

[Quantitative data analysis for live imaging of bone.

Science.gov (United States)

Seno, Shigeto

Bone tissue is a hard tissue, it was difficult to observe the interior of the bone tissue alive. With the progress of microscopic technology and fluorescent probe technology in recent years, it becomes possible to observe various activities of various cells forming bone society. On the other hand, the quantitative increase in data and the diversification and complexity of the images makes it difficult to perform quantitative analysis by visual inspection. It has been expected to develop a methodology for processing microscopic images and data analysis. In this article, we introduce the research field of bioimage informatics which is the boundary area of biology and information science, and then outline the basic image processing technology for quantitative analysis of live imaging data of bone.

Controlled AFM detachments and movement of nanoparticles: gold clusters on HOPG at different temperatures.

Science.gov (United States)

Tripathi, Manoj; Paolicelli, Guido; D'Addato, Sergio; Valeri, Sergio

2012-06-22

The effect of temperature on the onset of movement of gold nanoclusters (diameter 27 nm) deposited on highly oriented pyrolytic graphite (HOPG) has been studied by atomic force microscopy (AFM) techniques. Using the AFM with amplitude modulation (tapping mode AFM) we have stimulated and controlled the movement of individual clusters. We show how, at room temperature, controlled detachments and smooth movements can be obtained for clusters having dimensions comparable to or smaller than the tip radius. Displacement is practically visible in real time and it can be started and stopped easily by adjusting only one parameter, the tip amplitude oscillation. Analysing the energy dissipation signal at the onset of nanocluster sliding we evaluated a detachment threshold energy as a function of temperature in the range 300-413 K. We also analysed single cluster thermal induced displacement and combining this delicate procedure with AFM forced movement behaviour we conclude that detachment threshold energy is directly related to the activation energy of nanocluster diffusion and it scales linearly with temperature as expected for a single-particle thermally activated process.

Investigations of environmental induced effects on AlQ3 thin films by AFM phase imaging

International Nuclear Information System (INIS)

Shukla, Vivek Kumar; Kumar, Satyendra

2007-01-01

Tris(8-hydroxyquinoline) metal complex (AlQ 3 ) is a widely used light-emitting material in organic light emitting devices (OLEDs). The environmental stability is still a major problem with OLEDs and needs further improvement. In this report, an additional feature of Atomic Force Microscopy (AFM) was exploited with the aim to understand the environmental induced effects and physical phenomenon involved on AlQ 3 thin films. We have used phase imaging to identify the presence of other aggregation phases formed after annealing the thin film in different ambient and after white light exposure. An enhanced photoluminescence intensity is observed for the samples annealed in oxygen near 100 deg. C. The enhanced photoluminescence is understood in terms of formation of a new aggregation phase. The phase change and the fraction of new phase is estimated by phase images taken by atomic force microscopy (AFM). Light induced effects on AlQ 3 films exposed to white light in air and vacuum are characterized by atomic force microscopy (AFM) for surface morphology and phases present. The AFM images indicate enhanced crystallinity for the vacuum exposed samples. The phase with increased lifetime and hence enhanced crystallinity for vacuum exposed films has also been found by time correlated single photon counting (TCSPC) measurements. To the best of our knowledge, this study is applied for the first time on this material with the combination of topography and phase imaging in atomic force microscopy (AFM). The major aim was to take advantage of the additional feature of AFM-mode over the conventionally used

Quantitative phase analysis by neutron diffraction

Energy Technology Data Exchange (ETDEWEB)

Lee, Chang Hee; Song, Su Ho; Lee, Jin Ho; Shim, Hae Seop [Korea Atomic Energy Research Institute, Taejon (Korea)

1999-06-01

This study is to apply quantitative phase analysis (QPA) by neutron diffraction to the round robin samples provided by the International Union of Crystallography(IUCr). We measured neutron diffraction patterns for mixed samples which have several different weight percentages and their unique characteristic features. Neutron diffraction method has been known to be superior to its complementary methods such as X-ray or Synchrotron, but it is still accepted as highly reliable under limited conditions or samples. Neutron diffraction has strong capability especially on oxides due to its scattering cross-section of the oxygen and it can become a more strong tool for analysis on the industrial materials with this quantitative phase analysis techniques. By doing this study, we hope not only to do one of instrument performance tests on our HRPD but also to improve our ability on the analysis of neutron diffraction data by comparing our QPA results with others from any advanced reactor facilities. 14 refs., 4 figs., 6 tabs. (Author)

A Study of Moisture Damage in Plastomeric Polymer Modified Asphalt Binder Using Functionalized AFM Tips

Directory of Open Access Journals (Sweden)

Rafiqul Tarefder

2011-12-01

Full Text Available In this study, moisture damage in plastomeric polymer modified asphalt binder is investigated using Atomic Force Microscopy (AFM with chemically functionalized AFM tips. Four different percentages of plastomeric polymers and two antistripping agents such as Kling Beta and Lime are used to modify a base asphalt binder. Chemical functional groups such as -COOH, -CH3, -NH3, and –OH, that are commonly present in plastomeric polymer modified asphalt system, are used to functionalize the AFM tips. The force distance mode of AFM is used to measure the adhesion forces between a modified asphalt sample surface and the functionalized AFM tips. This enables the measurement of adhesion within an asphalt binder system. It is shown that the adhesion force values in dry sample changed substantially from that in wet conditioned samples. It is evident from this study that plastomeric modification does not help reduce moisture damage in asphalt. The percentage change in adhesion forces due to moisture is about 20 nN for the lime modified samples, and about 50 nN for the Kling Beta modified samples. This indicates that lime is more effective than Kling Beta for reducing moisture damage in plastomeric polymer modified asphalt.

Restoration of high-resolution AFM images captured with broken probes

Science.gov (United States)

Wang, Y. F.; Corrigan, D.; Forman, C.; Jarvis, S.; Kokaram, A.

2012-03-01

A type of artefact is induced by damage of the scanning probe when the Atomic Force Microscope (AFM) captures a material surface structure with nanoscale resolution. This artefact has a dramatic form of distortion rather than the traditional blurring artefacts. Practically, it is not easy to prevent the damage of the scanning probe. However, by using natural image deblurring techniques in image processing domain, a comparatively reliable estimation of the real sample surface structure can be generated. This paper introduces a novel Hough Transform technique as well as a Bayesian deblurring algorithm to remove this type of artefact. The deblurring result is successful at removing blur artefacts in the AFM artefact images. And the details of the fibril surface topography are well preserved.

Electrical characterisation of semiconductor structures using AFM techniques

International Nuclear Information System (INIS)

Kovac jr, J.; Kovac, J.; Hotovy, J.; Novotny, I.; Skriniarova, J.; Dutkova, E.; Balaz, P.

2011-01-01

The microscopic dimensions appear to be a fundamental limitation to many common measurement techniques. The use of Current-Atomic Force Microscopy (I-AFM) bids a possibility to acquire topography image along with the current flow mappings which can be lapped over in resulting image as presented in this paper. A current distribution on the ZnO surface of p-Si/n- ZnO diode structure with CdS or ZnS nanocrystalline quantum dot clusters at the interface has been measured. The resulting images show a conductivity mapping different from topography what induces a conductive channels at the edges of the ZnO grains. We have successfully used I-AFM method where conductive AFM tip is scanning over the surface of the sample to create a topography image along with a current flow mapping of p-Si substrate covered with CdS or ZnS nanocrystalline clusters overlapped by 100 nm thick n-ZnO layer. The measured current mappings of both samples revealed a formation of conductive channels between the clusters of quantum dots when the sample is forward biased. We are able to create 3D topography images of combined with the forward biased current mapping textures which gives complex information about local conductivity and using this method it should be possible to find hidden current leaks in the samples for example defects in most semiconductor materials. A drift current generated in p-n junction was recorded when the sample was reverse biased while the sample has been exposed to light. Possible UV light source should cause a higher reverse current due to high bandgap of ZnS clusters which is a motivation to further research. The devices fabricated from these structures have the potential applications for solar cells or broadband photodetectors. (authors)

Metrological AFMs and its application for versatile nano-dimensional metrology tasks

Science.gov (United States)

Dai, Gaoliang; Dziomba, T.; Pohlenz, F.; Danzebrink, H.-U.; Koenders, L.

2010-08-01

Traceable calibrations of various micro and nano measurement devices are crucial tasks for ensuring reliable measurements for micro and nanotechnology. Today metrological AFM are widely used for traceable calibrations of nano dimensional standards. In this paper, we introduced the developments of metrological force microscopes at PTB. Of the three metrological AFMs described here, one is capable of measuring in a volume of 25 mm x 25 mm x 5 mm. All instruments feature interferometers and the three-dimensional position measurements are thus directly traceable to the metre definition. Some calibration examples on, for instance, flatness standards, step height standards, one and two dimensional gratings are demonstrated.

Quantitative standard-less XRF analysis

International Nuclear Information System (INIS)

Ulitzka, S.

2002-01-01

Full text: For most analytical tasks in the mining and associated industries matrix-matched calibrations are used for the monitoring of ore grades and process control. In general, such calibrations are product specific (iron ore, bauxite, alumina, mineral sands, cement etc.) and apply to a relatively narrow concentration range but give the best precision and accuracy for those materials. A wide range of CRMs is available and for less common materials synthetic standards can be made up from 'pure' chemicals. At times, analysis of materials with varying matrices (powders, scales, fly ash, alloys, polymers, liquors, etc.) and diverse physical shapes (non-flat, metal drillings, thin layers on substrates etc.) is required that could also contain elements which are not part of a specific calibration. A qualitative analysis can provide information about the presence of certain elements and the relative intensities of element peaks in a scan can give a rough idea about their concentrations. More often however, quantitative values are required. The paper will look into the basics of quantitative standardless analysis and show results for some well-defined CRMs. Copyright (2002) Australian X-ray Analytical Association Inc

Nanomechanical probing of soft matter through hydrophobic AFM tips fabricated by two-photon polymerization

International Nuclear Information System (INIS)

Suriano, Raffaella; De Marco, Carmela; Turri, Stefano; Zandrini, Tommaso; Osellame, Roberto; Bragheri, Francesca

2016-01-01

Atomic force microscopy (AFM) nanoindentation of soft materials is a powerful tool for probing mechanical properties of biomaterials. Though many results have been reported in this field over the last decade, adhesion forces between the tip and the sample hinder the elastic modulus measurement when hydrophilic soft samples are investigated. Here, two-photon polymerization (2PP) technology was used to fabricate hydrophobic perfluoropolyether-based AFM tips. The hydrophobic 2PP tips allowed us to overcome the limitations of commercial and functionalized tips as well as to successfully measure the elastic modulus of medically relevant soft materials in air. Our results obtained in the characterization of poly(dimethyl siloxane) and polyethylene glycol hydrogels showed lower adhesion forces over a larger measurement range when compared to measurements performed with commercial tips. The elastic moduli measured by means of hydrophobic 2PP AFM tips were also found to be comparable to those obtained using conventional techniques for macroscopic samples. We successfully showed that the hydrophobic AFM tips developed by this highly versatile technology enable the study of mechanical properties of soft matter, benefiting from reduced sample–tip interactions, and a custom-made shape and dimension of the tips. (paper)

High Throughput Nanofabrication of Silicon Nanowire and Carbon Nanotube Tips on AFM Probes by Stencil-Deposited Catalysts

DEFF Research Database (Denmark)

Engstrøm, Daniel Southcott; Savu, Veronica; Zhu, Xueni

2011-01-01

scale nanostencil lithography. Individual vertical SiNWs were grown epitaxially by a catalytic vapor−liquid−solid (VLS) process and MWNTs were grown by a plasma-enhanced chemical vapor (PECVD) process on the AFM probes. The AFM probes were tested for imaging micrometers-deep trenches, where...... they demonstrated a significantly better performance than commercial high aspect ratio tips. Our method demonstrates a reliable and cost-efficient route toward wafer scale manufacturing of SiNW and MWNT AFM probes....

Reactor applications of quantitative diffraction analysis

International Nuclear Information System (INIS)

Feguson, I.F.

1976-09-01

Current work in quantitative diffraction analysis was presented under the main headings of: thermal systems, fast reactor systems, SGHWR applications and irradiation damage. Preliminary results are included on a comparison of various new instrumental methods of boron analysis as well as preliminary new results on Zircaloy corrosion, and materials transfer in liquid sodium. (author)

AFM measurements of novel solar cells. Studying electronic properties of Si-based radial junctions

Czech Academy of Sciences Publication Activity Database

Hývl, Matěj

-, č. 1 (2014), s. 52-53 ISSN 1439-4243 R&D Projects: GA ČR GA13-25747S; GA ČR GA13-12386S; GA MŠk(CZ) LM2011026 Institutional support: RVO:68378271 Keywords : AFM measurements * conductive cantilever * electronic properties * nanowires * PF TUNA Subject RIV: BM - Solid Matter Physics ; Magnetism http://www.imaging-git.com/science/scanning-probe-microscopy/afm-measurements-novel-solar- cells

Analysis of atomic force microscopy data for surface characterization using fuzzy logic

International Nuclear Information System (INIS)

Al-Mousa, Amjed; Niemann, Darrell L.; Niemann, Devin J.; Gunther, Norman G.; Rahman, Mahmud

2011-01-01

In this paper we present a methodology to characterize surface nanostructures of thin films. The methodology identifies and isolates nanostructures using Atomic Force Microscopy (AFM) data and extracts quantitative information, such as their size and shape. The fuzzy logic based methodology relies on a Fuzzy Inference Engine (FIE) to classify the data points as being top, bottom, uphill, or downhill. The resulting data sets are then further processed to extract quantitative information about the nanostructures. In the present work we introduce a mechanism which can consistently distinguish crowded surfaces from those with sparsely distributed structures and present an omni-directional search technique to improve the structural recognition accuracy. In order to demonstrate the effectiveness of our approach we present a case study which uses our approach to quantitatively identify particle sizes of two specimens each with a unique gold nanoparticle size distribution. - Research Highlights: → A Fuzzy logic analysis technique capable of characterizing AFM images of thin films. → The technique is applicable to different surfaces regardless of their densities. → Fuzzy logic technique does not require manual adjustment of the algorithm parameters. → The technique can quantitatively capture differences between surfaces. → This technique yields more realistic structure boundaries compared to other methods.

Quantitative analysis of myocardial tissue with digital autofluorescence microscopy

Directory of Open Access Journals (Sweden)

Thomas Jensen

2016-01-01

Full Text Available Background: The opportunity offered by whole slide scanners of automated histological analysis implies an ever increasing importance of digital pathology. To go beyond the importance of conventional pathology, however, digital pathology may need a basic histological starting point similar to that of hematoxylin and eosin staining in conventional pathology. This study presents an automated fluorescence-based microscopy approach providing highly detailed morphological data from unstained microsections. This data may provide a basic histological starting point from which further digital analysis including staining may benefit. Methods: This study explores the inherent tissue fluorescence, also known as autofluorescence, as a mean to quantitate cardiac tissue components in histological microsections. Data acquisition using a commercially available whole slide scanner and an image-based quantitation algorithm are presented. Results: It is shown that the autofluorescence intensity of unstained microsections at two different wavelengths is a suitable starting point for automated digital analysis of myocytes, fibrous tissue, lipofuscin, and the extracellular compartment. The output of the method is absolute quantitation along with accurate outlines of above-mentioned components. The digital quantitations are verified by comparison to point grid quantitations performed on the microsections after Van Gieson staining. Conclusion: The presented method is amply described as a prestain multicomponent quantitation and outlining tool for histological sections of cardiac tissue. The main perspective is the opportunity for combination with digital analysis of stained microsections, for which the method may provide an accurate digital framework.

Ultra-high aspect ratio replaceable AFM tips using deformation-suppressed focused ion beam milling

International Nuclear Information System (INIS)

Savenko, Alexey; Yildiz, Izzet; Petersen, Dirch Hjorth; Bøggild, Peter; Bartenwerfer, Malte; Krohs, Florian; Oliva, Maria; Harzendorf, Torsten

2013-01-01

Fabrication of ultra-high aspect ratio exchangeable and customizable tips for atomic force microscopy (AFM) using lateral focused ion beam (FIB) milling is presented. While on-axis FIB milling does allow high aspect ratio (HAR) AFM tips to be defined, lateral milling gives far better flexibility in terms of defining the shape and size of the tip. Due to beam-induced deformation, it has so far not been possible to define HAR structures using lateral FIB milling. In this work we obtain aspect ratios of up to 45, with tip diameters down to 9 nm, by a deformation-suppressing writing strategy. Several FIB milling strategies for obtaining sharper tips are discussed. Finally, assembly of the HAR tips on a custom-designed probe as well as the first AFM scanning is shown. (paper)

High-stress study of bioinspired multifunctional PEDOT:PSS/nanoclay nanocomposites using AFM, SEM and numerical simulation

Directory of Open Access Journals (Sweden)

Alfredo J. Diaz

2017-10-01

Full Text Available Bioinspired design has been central in the development of hierarchical nanocomposites. Particularly, the nacre-mimetic brick-and-mortar structure has shown excellent mechanical properties, as well as gas-barrier properties and optical transparency. Along with these intrinsic properties, the layered structure has also been utilized in sensing devices. Here we extend the multifunctionality of nacre-mimetics by designing an optically transparent and electron conductive coating based on PEDOT:PSS and nanoclays Laponite RD and Cloisite Na+. We carry out extensive characterization of the nanocomposite using transmittance spectra (transparency, conductive atomic force microscopy (conductivity, contact-resonance force microscopy (mechanical properties, and SEM combined with a variety of stress-strain AFM experiments and AFM numerical simulations (internal structure. We further study the nanoclay’s response to the application of pressure with multifrequency AFM and conductive AFM, whereby increases and decreases in conductivity can occur for the Laponite RD composites. We offer a possible mechanism to explain the changes in conductivity by modeling the coating as a 1-dimensional multibarrier potential for electron transport, and show that conductivity can change when the separation between the barriers changes under the application of pressure, and that the direction of the change depends on the energy of the electrons. We did not observe changes in conductivity under the application of pressure with AFM for the Cloisite Na+ nanocomposite, which has a large platelet size compared with the AFM probe diameter. No pressure-induced changes in conductivity were observed in the clay-free polymer either.

AFM lateral force calibration for an integrated probe using a calibration grating

International Nuclear Information System (INIS)

Wang, Huabin; Gee, Michelle L.

2014-01-01

Atomic force microscopy (AFM) friction measurements on hard and soft materials remain a challenge due to the difficulties associated with accurately calibrating the cantilever for lateral force measurement. One of the most widely accepted lateral force calibration methods is the wedge method. This method is often used in a simplified format but in so doing sacrifices accuracy. In the present work, we have further developed the wedge method to provide a lateral force calibration method for integrated AFM probes that is easy to use without compromising accuracy and reliability. Raw friction calibration data are collected from a single scan image by continuous ramping of the set point as the facets of a standard grating are scanned. These data are analysed to yield an accurate lateral force conversion/calibration factor that is not influenced by adhesion forces or load deviation. By demonstrating this new calibration method, we illustrate its reliability, speed and ease of execution. This method makes accessible reliable boundary lubrication studies on adhesive and heterogeneous surfaces that require spatial resolution of frictional forces. - Highlights: • We develop a simple and accurate method for lateral force calibration in AFM friction measurements. • We detail the basis of the method and illustrate how to use it and its reliability with example data. • Our method is easy, accurate and accounts for the affects of adhesion on friction measurements. • The method is applicable to integrated probes, as opposed to colloidal probes. • This allows accurate AFM friction measurements on spatially heterogeneous and adhesive surfaces

Direct AFM observation of an opening event of a DNA cuboid constructed via a prism structure.

Science.gov (United States)

Endo, Masayuki; Hidaka, Kumi; Sugiyama, Hiroshi

2011-04-07

A cuboid structure was constructed using a DNA origami design based on a square prism structure. The structure was characterized by atomic force microscopy (AFM) and dynamic light scattering. The real-time opening event of the cuboid was directly observed by high-speed AFM.

AFM of metallic nano-particles and nano-structures in heavily irradiated NaCl

OpenAIRE

Gaynutdinov, R; Vainshtein, DI; Hak, SJ; Tolstikhina, A; Den Hartog, HW

2003-01-01

AFM investigations are reported for heavily, electron irradiated NaCl crystals in ultra high vacuum (UHV) in the non-contact mode-with an UHV AFM/STM Omicron system. To avoid chemical reactions between the radiolytic Na and oxygen and water, the irradiated samples were cleaved and prepared for the experiments in UHV At the surface of freshly cleaved samples, we have observed sodium nano-precipitates with shapes, which depend on the irradiation dose and the volume fraction of the radiolytic Na...

High precision attachment of silver nanoparticles on AFM tips by dielectrophoresis.

Science.gov (United States)

Leiterer, Christian; Wünsche, Erik; Singh, Prabha; Albert, Jens; Köhler, Johann M; Deckert, Volker; Fritzsche, Wolfgang

2016-05-01

AFM tips are modified with silver nanoparticles using an AC electrical field. The used technique works with sub-micron precision and also does not require chemical modification of the tip. Based on the electrical parameters applied in the process, particle density and particle position on the apex of the tip can be adjusted. The feasibility of the method is proven by subsequent tip-enhanced Raman spectroscopy (TERS) measurements using the fabricated tips as a measurement probe. Since this modification process itself does not require any lithographic processing, the technique can be easily adapted to modify AFM tips with a variety of nanostructures with pre-defined properties, while being parallelizable for a potential commercial application.

Custom AFM for X-ray beamlines: in situ biological investigations under physiological conditions

Energy Technology Data Exchange (ETDEWEB)

Gumí-Audenis, B. [ESRF, The European Synchrotron, Grenoble (France); Institute for Bioengineering of Catalonia (IBEC), Barcelona (Spain); Physical Chemistry Department, Universitat de Barcelona, Barcelona (Spain); Networking Biomedical Research Center on Bioengineering, Biomaterials and Nanomedicine (CIBER-BBN), Madrid (Spain); Carlà, F. [ESRF, The European Synchrotron, Grenoble (France); Vitorino, M. V. [University of Lisboa, Falculty of Science, Biosystems and Integrative Sciences Institute - BIOISI, Lisbon (Portugal); Panzarella, A. [ESRF, The European Synchrotron, Grenoble (France); Porcar, L. [Institut Laue-Langevin, Grenoble (France); Boilot, M. [ORTEC, Marseille (France); Guerber, S. [CEA, LETI Grenoble (France); Bernard, P. [ESRF, The European Synchrotron, Grenoble (France); Rodrigues, M. S. [University of Lisboa, Falculty of Science, Biosystems and Integrative Sciences Institute - BIOISI, Lisbon (Portugal); Sanz, F.; Giannotti, M. I. [Institute for Bioengineering of Catalonia (IBEC), Barcelona (Spain); Physical Chemistry Department, Universitat de Barcelona, Barcelona (Spain); Networking Biomedical Research Center on Bioengineering, Biomaterials and Nanomedicine (CIBER-BBN), Madrid (Spain); Costa, L., E-mail: luca.costa@esrf.fr [ESRF, The European Synchrotron, Grenoble (France)

2015-09-30

The performance of a custom atomic force microscope for grazing-incidence X-ray experiments on hydrated soft and biological samples is presented. A fast atomic force microscope (AFM) has been developed that can be installed as a sample holder for grazing-incidence X-ray experiments at solid/gas or solid/liquid interfaces. It allows a wide range of possible investigations, including soft and biological samples under physiological conditions (hydrated specimens). The structural information obtained using the X-rays is combined with the data gathered with the AFM (morphology and mechanical properties), providing a unique characterization of the specimen and its dynamics in situ during an experiment. In this work, lipid monolayers and bilayers in air or liquid environment have been investigated by means of AFM, both with imaging and force spectroscopy, and X-ray reflectivity. In addition, this combination allows the radiation damage induced by the beam on the sample to be studied, as has been observed on DOPC and DPPC supported lipid bilayers under physiological conditions.

Direct comparison of AFM and SEM measurements on the same set of nanoparticles

International Nuclear Information System (INIS)

Delvallée, A; Feltin, N; Ducourtieux, S; Trabelsi, M; Hochepied, J F

2015-01-01

This article is the first step in the development of a hybrid metrology combining AFM and SEM techniques for measuring the dimensions of a nanoparticle population in 3D space (X,Y,Z). This method exploits the strengths of each technique on the same set of nanoparticles. AFM is used for measuring the nanoparticle height and the measurements along X and Y axes are deduced from SEM images. A sampling method is proposed in order to obtain the best deposition conditions of SiO 2 and gold nanoparticles on mica or silicon substrates. Only the isolated nanoparticles are taken into account in the histogram of size distribution. Moreover, a semi-automatic Matlab routine has also been developed to process the AFM and SEM images, measure and count the nanoparticles. This routine allows the user to exclusively select the isolated nanoparticles through a control interface. The measurements have been performed on spherical-like nanoparticles to test the method by comparing the results obtained with both techniques. (paper)

Surface electrical properties of stainless steel fibres: An AFM-based study

International Nuclear Information System (INIS)

Yin, Jun; D’Haese, Cécile; Nysten, Bernard

2015-01-01

Highlights: • Surface electrical conductivity of stainless steel fibre is measured and mapped by CS-AFM. • Surface potential of stainless steel fibre is measured and mapped by KPFM. • Surface electronic properties are governed by the chromium oxide passivation layer. • Electron tunnelling through the passivation layer is the dominant mechanisms for conduction. - Abstract: Atomic force microscopy (AFM) electrical modes were used to study the surface electrical properties of stainless steel fibres. The surface electrical conductivity was studied by current sensing AFM and I–V spectroscopy. Kelvin probe force microscopy was used to measure the surface contact potential. The oxide film, known as passivation layer, covering the fibre surface gives rise to the observation of an apparently semiconducting behaviour. The passivation layer generally exhibits a p-type semiconducting behaviour, which is attributed to the predominant formation of chromium oxide on the surface of the stainless steel fibres. At the nanoscale, different behaviours are observed from points to points, which may be attributed to local variations of the chemical composition and/or thickness of the passivation layer. I–V curves are well fitted with an electron tunnelling model, indicating that electron tunnelling may be the predominant mechanism for electron transport

Quantitative risk analysis of a space shuttle subsystem

International Nuclear Information System (INIS)

Frank, M.V.

1989-01-01

This paper reports that in an attempt to investigate methods for risk management other than qualitative analysis techniques, NASA has funded pilot study quantitative risk analyses for space shuttle subsystems. The authors performed one such study of two shuttle subsystems with McDonnell Douglas Astronautics Company. The subsystems were the auxiliary power units (APU) on the orbiter, and the hydraulic power units on the solid rocket booster. The technology and results of the APU study are presented in this paper. Drawing from a rich in-flight database as well as from a wealth of tests and analyses, the study quantitatively assessed the risk of APU-initiated scenarios on the shuttle during all phases of a flight mission. Damage states of interest were loss of crew/vehicle, aborted mission, and launch scrub. A quantitative risk analysis approach to deciding on important items for risk management was contrasted with the current NASA failure mode and effects analysis/critical item list approach

Uncertainty of quantitative microbiological methods of pharmaceutical analysis.

Science.gov (United States)

Gunar, O V; Sakhno, N G

2015-12-30

The total uncertainty of quantitative microbiological methods, used in pharmaceutical analysis, consists of several components. The analysis of the most important sources of the quantitative microbiological methods variability demonstrated no effect of culture media and plate-count techniques in the estimation of microbial count while the highly significant effect of other factors (type of microorganism, pharmaceutical product and individual reading and interpreting errors) was established. The most appropriate method of statistical analysis of such data was ANOVA which enabled not only the effect of individual factors to be estimated but also their interactions. Considering all the elements of uncertainty and combining them mathematically the combined relative uncertainty of the test results was estimated both for method of quantitative examination of non-sterile pharmaceuticals and microbial count technique without any product. These data did not exceed 35%, appropriated for a traditional plate count methods. Copyright © 2015 Elsevier B.V. All rights reserved.

Quantification of the number of EP3 receptors on a living CHO cell surface by the AFM

International Nuclear Information System (INIS)

Kim, Hyonchol; Arakawa, Hideo; Hatae, Noriyuki; Sugimoto, Yukihiko; Matsumoto, Osamu; Osada, Toshiya; Ichikawa, Atsushi; Ikai, Atsushi

2006-01-01

The distribution of EP3 receptors on a living cell surface was quantitatively studied by atomic force microscopy (AFM). Green fluorescent protein (GFP) was introduced to the extracellular region of the EP3 receptor on a CHO cell. A microbead was used as a probe to ensure certain contact area, whose surface was coated with anti-GFP antibody. The interactions between the antibodies and GFP molecules on the cell surface were recorded to observe the distribution of the receptors. The result indicated that EP3 receptors were distributed on the CHO cell surface not uniformly but in small patches coincident with immunohistochemical observation. Repeated measurements on the same area of cell surface gave confirmation that it was unlikely that the receptors were extracted from the cell membrane during the experiments. The measurement of single molecular interaction between GFP and the anti-GFP antibody was succeeded on the cell surface using compression-free force spectroscopy. The value of separation work required to break a single molecular pair was estimated to be about 1.5x10 -18 J. The number of EP3 receptor on the CHO cell surface was estimated using this value to be about 1x10 4 under the assumption that the area of the cell surface was about 5000 μm 2 . These results indicated that the number of receptors on a living cell surface could be quantified through the force measurement by the AFM

Influence of the surface chemistry on the nanotribological behaviour of (AFM tip/graphite) couples

International Nuclear Information System (INIS)

Jradi, Khalil; Schmitt, Marjorie; Bistac, Sophie

2012-01-01

The development of the nanotechnology has made essential the knowledge of the tribological behaviour of carbonaceous materials, and more particularly of graphite. Atomic force microscopy (AFM) is thus used to study the friction properties at this nanoscopic scale. In this work, results concerning the friction of AFM tips against graphite pins are presented, with a particular emphasis on the effect of the chemical modification of these tips on the tribological behaviour of graphite.

AFM Structural Characterization of Drinking Water Biofilm ...

Science.gov (United States)

Due to the complexity of mixed culture drinking water biofilm, direct visual observation under in situ conditions has been challenging. In this study, atomic force microscopy (AFM) revealed the three dimensional morphology and arrangement of drinking water relevant biofilm in air and aqueous solution. Operating parameters were optimized to improve imaging of structural details for a mature biofilm in liquid. By using a soft cantilever (0.03 N/m) and slow scan rate (0.5 Hz), biofilm and individual bacterial cell’s structural topography were resolved and continuously imaged in liquid without loss of spatial resolution or sample damage. The developed methodology will allow future in situ investigations to temporally monitor mixed culture drinking water biofilm structural changes during disinfection treatments. Due to the complexity of mixed culture drinking water biofilm, direct visual observation under in situ conditions has been challenging. In this study, atomic force microscopy (AFM) revealed the three dimensional morphology and arrangement of drinking water relevant biofilm in air and aqueous solution. Operating parameters were optimized to improve imaging of structural details for a mature biofilm in liquid. By using a soft cantilever (0.03 N/m) and slow scan rate (0.5 Hz), biofilm and individual bacterial cell’s structural topography were resolved and continuously imaged in liquid without loss of spatial resolution or sample damage. The developed methodo

Nano-Electrochemistry and Nano-Electrografting with an Original Combined AFM-SECM

Directory of Open Access Journals (Sweden)

Ammar Ben Brahim

2013-05-01

Full Text Available This study demonstrates the advantages of the combination between atomic force microscopy and scanning electrochemical microscopy. The combined technique can perform nano-electrochemical measurements onto agarose surface and nano-electrografting of non-conducting polymers onto conducting surfaces. This work was achieved by manufacturing an original Atomic Force Microscopy-Scanning ElectroChemical Microscopy (AFM-SECM electrode. The capabilities of the AFM-SECM-electrode were tested with the nano-electrografting of vinylic monomers initiated by aryl diazonium salts. Nano-electrochemical and technical processes were thoroughly described, so as to allow experiments reproducing. A plausible explanation of chemical and electrochemical mechanisms, leading to the nano-grafting process, was reported. This combined technique represents the first step towards improved nano-processes for the nano-electrografting.

Controlled AFM manipulation of small nanoparticles and assembly of hybrid nanostructures

International Nuclear Information System (INIS)

Kim, Suenne; Shafiei, Farbod; Ratchford, Daniel; Li Xiaoqin

2011-01-01

We demonstrate controlled manipulation of semiconductor and metallic nanoparticles (NPs) with 5-15 nm diameters and assemble these NPs into hybrid structures. The manipulation is accomplished under ambient environment using a commercial atomic force microscope (AFM). There are particular difficulties associated with manipulating NPs this small. In addition to spatial drift, the shape of an asymmetric AFM tip has to be taken into account in order to understand the intended and actual manipulation results. Furthermore, small NPs often attach to the tip via electrostatic interaction and modify the effective tip shape. We suggest a method for detaching the NPs by performing a pseudo-manipulation step. Finally, we show by example the ability to assemble these small NPs into prototypical hybrid nanostructures with well-defined composition and geometry.

Nano-Electrochemistry and Nano-Electrografting with an Original Combined AFM-SECM

Science.gov (United States)

Ghorbal, Achraf; Grisotto, Federico; Charlier, Julienne; Palacin, Serge; Goyer, Cédric; Demaille, Christophe; Ben Brahim, Ammar

2013-01-01

This study demonstrates the advantages of the combination between atomic force microscopy and scanning electrochemical microscopy. The combined technique can perform nano-electrochemical measurements onto agarose surface and nano-electrografting of non-conducting polymers onto conducting surfaces. This work was achieved by manufacturing an original Atomic Force Microscopy-Scanning ElectroChemical Microscopy (AFM-SECM) electrode. The capabilities of the AFM-SECM-electrode were tested with the nano-electrografting of vinylic monomers initiated by aryl diazonium salts. Nano-electrochemical and technical processes were thoroughly described, so as to allow experiments reproducing. A plausible explanation of chemical and electrochemical mechanisms, leading to the nano-grafting process, was reported. This combined technique represents the first step towards improved nano-processes for the nano-electrografting. PMID:28348337

Quantitative Analysis of cardiac SPECT

International Nuclear Information System (INIS)

Nekolla, S.G.; Bengel, F.M.

2004-01-01

The quantitative analysis of myocardial SPECT images is a powerful tool to extract the highly specific radio tracer uptake in these studies. If compared to normal data bases, the uptake values can be calibrated on an individual basis. Doing so increases the reproducibility of the analysis substantially. Based on the development over the last three decades starting from planar scinitigraphy, this paper discusses the methods used today incorporating the changes due to tomographic image acquisitions. Finally, the limitations of these approaches as well as consequences from most recent hardware developments, commercial analysis packages and a wider view of the description of the left ventricle are discussed. (orig.)

Optical Beam Deflection Based AFM with Integrated Hardware and Software Platform for an Undergraduate Engineering Laboratory

Directory of Open Access Journals (Sweden)

Siu Hong Loh

2017-02-01

Full Text Available Atomic force microscopy (AFM has been used extensively in nanoscience research since its invention. Recently, many teaching laboratories in colleges, undergraduate institutions, and even high schools incorporate AFM as an effective teaching tool for nanoscience education. This paper presents an optical beam deflection (OBD based atomic force microscope, designed specifically for the undergraduate engineering laboratory as a teaching instrument. An electronic module for signal conditioning was built with components that are commonly available in an undergraduate electronic laboratory. In addition to off-the-shelf mechanical parts and optics, the design of custom-built mechanical parts waskept as simple as possible. Hence, the overall cost for the setup is greatly reduced. The AFM controller was developed using National Instruments Educational Laboratory Virtual Instrumentation Suite (NI ELVIS, an integrated hardware and software platform which can be programmed in LabVIEW. A simple yet effective control algorithm for scanning and feedback control was developed. Despite the use of an educational platform and low-cost components from the undergraduate laboratory, the developed AFM is capable of performing imaging in constant-force mode with submicron resolution and at reasonable scanning speed (approximately 18 min per image. Therefore, the AFM is suitable to be used as an educational tool for nanoscience. Moreover, the construction of the system can be a valuable educational experience for electronic and mechanical engineering students.

AFM Nanotools for Surgery of Biological Cells

Energy Technology Data Exchange (ETDEWEB)

Beard, J D; Gordeev, S N [Department of Physics, Claverton Down, University of Bath, Bath, BA2 7AY (United Kingdom); Guy, R H, E-mail: jdb28@bath.ac.uk [Department of Pharmacy and Pharmacology, Claverton Down, University of Bath, Bath, BA2 7AY (United Kingdom)

2011-03-01

Using a method of electron-beam induced deposition, we have been able to fabricate specialized AFM probes with application as 'nanotools' for the manipulation of biological structures ('nanosurgery'). We describe several such tools, including a 'nanoscalpel', 'nanoneedles' for probing intracellular structures, and a 'nanotome' which can separate surface layers from a biological structure. These applications are demonstrated by performing nanomanipulation on corneocyte cells from the outer layer of human skin.

Tumor suppressor protein SMAR1 modulates the roughness of cell surface: combined AFM and SEM study

Directory of Open Access Journals (Sweden)

Mamgain Hitesh

2009-10-01

Full Text Available Abstract Background Imaging tools such as scanning electron microscope (SEM and atomic force microscope (AFM can be used to produce high-resolution topographic images of biomedical specimens and hence are well suited for imaging alterations in cell morphology. We have studied the correlation of SMAR1 expression with cell surface smoothness in cell lines as well as in different grades of human breast cancer and mouse tumor sections. Methods We validated knockdown and overexpression of SMAR1 using RT-PCR as well as Western blotting in human embryonic kidney (HEK 293, human breast cancer (MCF-7 and mouse melanoma (B16F1 cell lines. The samples were then processed for cell surface roughness studies using atomic force microscopy (AFM and scanning electron microscopy (SEM. The same samples were used for microarray analysis as well. Tumors sections from control and SMAR1 treated mice as well as tissues sections from different grades of human breast cancer on poly L-lysine coated slides were used for AFM and SEM studies. Results Tumor sections from mice injected with melanoma cells showed pronounced surface roughness. In contrast, tumor sections obtained from nude mice that were first injected with melanoma cells followed by repeated injections of SMAR1-P44 peptide, exhibited relatively smoother surface profile. Interestingly, human breast cancer tissue sections that showed reduced SMAR1 expression exhibited increased surface roughness compared to the adjacent normal breast tissue. Our AFM data establishes that treatment of cells with SMAR1-P44 results into increase in cytoskeletal volume that is supported by comparative gene expression data showing an increase in the expression of specific cytoskeletal proteins compared to the control cells. Altogether, these findings indicate that tumor suppressor function of SMAR1 might be exhibited through smoothening of cell surface by regulating expression of cell surface proteins. Conclusion Tumor suppressor

Modular design of AFM probe with sputtered silicon tip

DEFF Research Database (Denmark)

Rasmussen, Peter; Thaysen, Jacob; Bouwstra, Siebe

2001-01-01

of the thin films constituting the cantilever. The AFM probe has an integrated tip made of a thick sputtered silicon layer, which is deposited after the probe has been defined and just before the cantilevers are released. The tips are so-called rocket tips made by reactive ion etching. We present probes...

Application of atomic force microscopy as a nanotechnology tool in food science.

Science.gov (United States)

Yang, Hongshun; Wang, Yifen; Lai, Shaojuan; An, Hongjie; Li, Yunfei; Chen, Fusheng

2007-05-01

Atomic force microscopy (AFM) provides a method for detecting nanoscale structural information. First, this review explains the fundamentals of AFM, including principle, manipulation, and analysis. Applications of AFM are then reported in food science and technology research, including qualitative macromolecule and polymer imaging, complicated or quantitative structure analysis, molecular interaction, molecular manipulation, surface topography, and nanofood characterization. The results suggested that AFM could bring insightful knowledge on food properties, and the AFM analysis could be used to illustrate some mechanisms of property changes during processing and storage. However, the current difficulty in applying AFM to food research is lacking appropriate methodology for different food systems. Better understanding of AFM technology and developing corresponding methodology for complicated food systems would lead to a more in-depth understanding of food properties at macromolecular levels and enlarge their applications. The AFM results could greatly improve the food processing and storage technologies.

Good practices for quantitative bias analysis.

Science.gov (United States)

Lash, Timothy L; Fox, Matthew P; MacLehose, Richard F; Maldonado, George; McCandless, Lawrence C; Greenland, Sander

2014-12-01

Quantitative bias analysis serves several objectives in epidemiological research. First, it provides a quantitative estimate of the direction, magnitude and uncertainty arising from systematic errors. Second, the acts of identifying sources of systematic error, writing down models to quantify them, assigning values to the bias parameters and interpreting the results combat the human tendency towards overconfidence in research results, syntheses and critiques and the inferences that rest upon them. Finally, by suggesting aspects that dominate uncertainty in a particular research result or topic area, bias analysis can guide efficient allocation of sparse research resources. The fundamental methods of bias analyses have been known for decades, and there have been calls for more widespread use for nearly as long. There was a time when some believed that bias analyses were rarely undertaken because the methods were not widely known and because automated computing tools were not readily available to implement the methods. These shortcomings have been largely resolved. We must, therefore, contemplate other barriers to implementation. One possibility is that practitioners avoid the analyses because they lack confidence in the practice of bias analysis. The purpose of this paper is therefore to describe what we view as good practices for applying quantitative bias analysis to epidemiological data, directed towards those familiar with the methods. We focus on answering questions often posed to those of us who advocate incorporation of bias analysis methods into teaching and research. These include the following. When is bias analysis practical and productive? How does one select the biases that ought to be addressed? How does one select a method to model biases? How does one assign values to the parameters of a bias model? How does one present and interpret a bias analysis?. We hope that our guide to good practices for conducting and presenting bias analyses will encourage

Quantitative phase analysis in industrial research

International Nuclear Information System (INIS)

Ahmad Monshi

1996-01-01

X-Ray Diffraction (XRD) is the only technique able to identify phase and all the other analytical techniques give information about the elements. Quantitative phase analysis of minerals and industrial products is logically the next step after a qualitative examination and is of great importance in industrial research. Since the application of XRD in industry, early in this century, workers were trying to develop quantitative XRD methods. In this paper some of the important methods are briefly discussed and partly compared. These methods are Internal Standard, Known Additions, Double Dilution, External Standard, Direct Comparison, Diffraction Absorption and Ratio of Slopes

High-field magnetoconductance in La-Sr manganites of FM and AFM ground states

Science.gov (United States)

Jirák, Zdeněk; Kaman, Ondřej; Knížek, Karel; Levinský, Petr; Míšek, Martin; Veverka, Pavel; Hejtmánek, Jiří

2018-06-01

Large-grain La1-xSrxMnO3 ceramic samples of compositions x = 0.45 and 0.55, representing the ferromagnetic (FM) and A-type antiferromagnetic (AFM) ground states, were produced via classical sintering at 1500 °C of cold-pressed sol-gel prepared single-phase nanoparticles. Using the same precursors, nanogranular forms of both manganite ceramics were prepared by fast spark plasma sintering at low temperature of 900 °C, which limits the growth of crystal grains. The magnetotransport of both the bulk and nanogranular forms was investigated in a broad range of magnetic fields up to 130 kOe and analyzed on the basis of detailed magnetic measurements. Both the large-grain and nanogranular systems with x = 0.45, possessing a pure FM state with similar Curie tempereature TC ≈ 345 K), show nearly the same conductivity enhancement in external fields when expressed relatively to the zero-field values. This positive magnetoconductance (MC) can be separated into two terms: (i) the hysteretic low-field MC that reflects the field-induced orientation of magnetic moments of individual grains, and (ii) the high-field MC that depends linearly on external field. In the case of large-grain ceramics with x = 0.55, a partially ordered FM state formed below TC = 264 K is replaced by pure A-type AFM ground state below 204 K. This A-type AFM state is characterized by positive magnetoconductance that is essentially of quadratic dependence on external field in the investigated range up to 130 kOe. On contrary, the nanogranular product with x = 0.55 exhibits a mixed FM/AFM state at low temperatures, and, as a consequence, its magnetotransport combines the features of FM and A-type AFM systems, in which the quadratic term is much enhanced and clearly dominates at high fields. For interpretation of observed behaviors, the theory of grain-boundary tunneling is revisited.

Using XAFS, EDAX and AFM in comparative study of various natural and synthetic emeralds

International Nuclear Information System (INIS)

Parikh, P.; Saini, N.L.; Dalela, S.; Bhardwaj, D.M.; Fernandes, S.; Gupta, R.P.; Garg, K.B.

2003-01-01

We have performed XAFS, EDAX and AFM studies on some natural and synthetic emeralds. While the XAFS results yield information on changes in the valence of the Cr ion and the n-n distance the AFM is used to determine the areal atomic density on surface of the crystals. It is a pilot study to explore if the three techniques can offer a possible way of distinguishing between the natural and synthetic emeralds and the results are promising

Recombinant albumin adsorption on mica studied by AFM and streaming potential measurements.

Science.gov (United States)

Kujda, Marta; Adamczyk, Zbigniew; Morga, Maria; Sofińska, Kamila

2015-03-01

Recombinant human serum albumin (rHSA) in monomeric state is widely used in pharmaceutical industry as a drug excipient and for preparing coatings for medical devices. In this work the adsorption process of rHSA on model mica surface at pH 3.5 was studied using the atomic force microscopy (AFM) and in situ streaming potential measurements. The kinetics of albumin adsorption was determined by a direct enumeration of single molecules over various substrate areas. These results were consistent with streaming potential measurements carried out for the parallel-plate channel flow and with theoretical predictions derived from the random sequential adsorption (RSA) model. Desorption kinetics of albumin under flow conditions was also evaluated via the streaming potential measurements. In this way, the amount of irreversibly bound albumin was quantitatively evaluated to be 0.64 and 1.2 mg m(-2) for ionic strength of 0.01 and 0.15 M, respectively. This agrees with previous results obtained for HSA and theoretical calculations derived from the RSA model. Additionally, it was demonstrated that there existed a fraction of reversibly bound albumin that can be fully eluted within a few hours. The binding energy of these fraction of molecules was -18 kT that is consistent with the electrostatic controlled adsorption mechanism of albumin at this pH. It was concluded that the rHSA monolayers of well-defined coverage can find applications for quantitatively analyzing ligand binding and for performing efficient biomaterials and immunological tests. Copyright © 2015 Elsevier B.V. All rights reserved.

Probing lipid membrane electrostatics

Science.gov (United States)

Yang, Yi

The electrostatic properties of lipid bilayer membranes play a significant role in many biological processes. Atomic force microscopy (AFM) is highly sensitive to membrane surface potential in electrolyte solutions. With fully characterized probe tips, AFM can perform quantitative electrostatic analysis of lipid membranes. Electrostatic interactions between Silicon nitride probes and supported zwitterionic dioleoylphosphatidylcholine (DOPC) bilayer with a variable fraction of anionic dioleoylphosphatidylserine (DOPS) were measured by AFM. Classical Gouy-Chapman theory was used to model the membrane electrostatics. The nonlinear Poisson-Boltzmann equation was numerically solved with finite element method to provide the potential distribution around the AFM tips. Theoretical tip-sample electrostatic interactions were calculated with the surface integral of both Maxwell and osmotic stress tensors on tip surface. The measured forces were interpreted with theoretical forces and the resulting surface charge densities of the membrane surfaces were in quantitative agreement with the Gouy-Chapman-Stern model of membrane charge regulation. It was demonstrated that the AFM can quantitatively detect membrane surface potential at a separation of several screening lengths, and that the AFM probe only perturbs the membrane surface potential by external field created by the internai membrane dipole moment. The analysis yields a dipole moment of 1.5 Debye per lipid with a dipole potential of +275 mV for supported DOPC membranes. This new ability to quantitatively measure the membrane dipole density in a noninvasive manner will be useful in identifying the biological effects of the dipole potential. Finally, heterogeneous model membranes were studied with fluid electric force microscopy (FEFM). Electrostatic mapping was demonstrated with 50 nm resolution. The capabilities of quantitative electrostatic measurement and lateral charge density mapping make AFM a unique and powerful

AFM studies on heavy ion irradiated YBCO single crystals

International Nuclear Information System (INIS)

Lakhani, Archana; Marhas, M.K.; Saravanan, P.; Ganesan, V.; Srinivasan, R.; Kanjilal, D.; Mehta, G.K.; Elizabeth, Suja; Bhat, H.L.

2000-01-01

Atomic Force Microscopy (AFM) is extensively used to characterise the surface morphology of high energy ion irradiated single crystals of high temperature superconductor - YBCO. Our earlier systematic studies on thin films of YBCO under high energy and heavy ion irradiation shows clear evidence of ion induced sputtering or erosion, even though the effect is more on the grain boundaries. These earlier results were supported by electrical resistance measurements. In order to understand more clearly, the nature of surface modification at these high energies, AFM studies were carried out on single crystals of YBCO. Single crystals were chosen in order to see the effect on crystallites alone without interference from grain boundaries. 200 MeV gold ions were used for investigation using the facilities available at Nuclear Science Centre, New Delhi. The type of ion and the range of energies were chosen to meet the threshold for electronically mediated defect production. The results are in conformity with our earlier studies and will be described in detail in the context of electronic energy loss mediated sputtering or erosion. (author)

Micro-computer system for quantitative image analysis of damage microstructure

International Nuclear Information System (INIS)

Kohyama, A.; Kohno, Y.; Satoh, K.; Igata, N.

1984-01-01

Quantitative image analysis of radiation induced damage microstructure is very important in evaluating material behaviors in radiation environment. But, quite a few improvement have been seen in quantitative analysis of damage microstructure in these decades. The objective of this work is to develop new system for quantitative image analysis of damage microstructure which could improve accuracy and efficiency of data sampling and processing and could enable to get new information about mutual relations among dislocations, precipitates, cavities, grain boundaries, etc. In this system, data sampling is done with X-Y digitizer. The cavity microstructure in dual-ion irradiated 316 SS is analyzed and the effectiveness of this system is discussed. (orig.)

Joint Research on Scatterometry and AFM Wafer Metrology

OpenAIRE

Bodermann, B.; Buhr, E.; Danzebrink, H.U.; Bär, M.; Scholze, F.; Krumrey, M.; Wurm, M.; Klapetek, P.; Hansen, P.E.; Korpelainen, V.; Van Veghel, M.; Yacoot, A.; Siitonen, S.; El Gawhary, O.; Burger, S.

2011-01-01

Supported by the European Commission and EURAMET, a consortium of 10 participants from national metrology institutes, universities and companies has started a joint research project with the aim of overcoming current challenges in optical scatterometry for traceable linewidth metrology. Both experimental and modelling methods will be enhanced and different methods will be compared with each other and with specially adapted atomic force microscopy (AFM) and scanning electron microscopy (SEM) m...

Cuticle scale measurement of animal fibers by SEM and AFM

CSIR Research Space (South Africa)

Notayi, M

2013-12-01

Full Text Available -1 51st Microscopy Society of Southern Africa (MSSA) Conference, Farm Inn, Pretoria, 3-6 December 2013 Cuticle scale measurement of animal fibers by SEM and AFM Notayi M, Engelbrechts JAA, Lee ME, Goosen WE, Hunter L and Botha AF Abstract...

An AFM and XPS study of corrosion caused by micro-liquid of dilute sulfuric acid on stainless steel

International Nuclear Information System (INIS)

Wang Rongguang

2004-01-01

Micro-liquid of dilute sulfuric acid deposited on SUS304 steel surface were observed with the ac non-contact mode of an atomic force microscopy (AFM), and the detail of the corrosion process caused by them was investigated with the contact mode of the AFM, X-ray photoelectron spectroscopy (XPS) and wavelength dispersive X-ray spectroscopy (WDXS). As a result, even not applying bias voltages between the tip of the cantilever and the specimen, micro-liquid of sulfuric acid can be successfully imaged using the ac non-contact mode of AFM. Two shapes of micro-acid, i.e., micro-droplets and micro-films, were found to co-exist on the specimen surface. On areas covered by micro-films of acid, only small corrosion product particles appeared and no corrosion pits were found. Beneath micro-droplets, corrosion reaction continue to produce pits until they were all consumed to form a corrosion product (mainly iron oxides) with almost the same shape with the droplet. The total corrosion reaction time was speculated to be between 690 and 1500 ks. The corrosion product formed from micro-droplets was believed to be a process of accumulating small corrosion product particles from the liquid/substrate interface to the surface of the formerly produced corrosion product. The XPS and WDXS analysis also supports the above results

Combining adhesive contact mechanics with a viscoelastic material model to probe local material properties by AFM.

Science.gov (United States)

Ganser, Christian; Czibula, Caterina; Tscharnuter, Daniel; Schöberl, Thomas; Teichert, Christian; Hirn, Ulrich

2017-12-20

Viscoelastic properties are often measured using probe based techniques such as nanoindentation (NI) and atomic force microscopy (AFM). Rarely, however, are these methods verified. In this article, we present a method that combines contact mechanics with a viscoelastic model (VEM) composed of springs and dashpots. We further show how to use this model to determine viscoelastic properties from creep curves recorded by a probe based technique. We focus on using the standard linear solid model and the generalized Maxwell model of order 2. The method operates in the range of 0.01 Hz to 1 Hz. Our approach is suitable for rough surfaces by providing a defined contact area using plastic pre-deformation of the material. The very same procedure is used to evaluate AFM based measurements as well as NI measurements performed on polymer samples made from poly(methyl methacrylate) and polycarbonate. The results of these measurements are then compared to those obtained by tensile creep tests also performed on the same samples. It is found that the tensile test results differ considerably from the results obtained by AFM and NI methods. The similarity between the AFM results and NI results suggests that the proposed method is capable of yielding results comparable to NI but with the advantage of the imaging possibilities of AFM. Furthermore, all three methods allowed a clear distinction between PC and PMMA by means of their respective viscoelastic properties.

Quantitative Structure-Activity Relationship Analysis of the ...

African Journals Online (AJOL)

Erah

Quantitative Structure-Activity Relationship Analysis of the Anticonvulsant ... Two types of molecular descriptors, including the 2D autocorrelation ..... It is based on the simulation of natural .... clustering anticonvulsant, antidepressant, and.

Imaging and quantitative data acquisition of biological cell walls with Atomic Force Microscopy and Scanning Acoustic Microscopy

Energy Technology Data Exchange (ETDEWEB)

Tittmann, B. R. [Penn State; Xi, X. [Penn State

2014-09-01

This chapter demonstrates the feasibility of Atomic Force Microscopy (AFM) and High Frequency Scanning Acoustic Microscopy (HF-SAM) as tools to characterize biological tissues. Both the AFM and the SAM have shown to provide imaging (with different resolution) and quantitative elasticity measuring abilities. Plant cell walls with minimal disturbance and under conditions of their native state have been examined with these two kinds of microscopy. After descriptions of both the SAM and AFM, their special features and the typical sample preparation is discussed. The sample preparation is focused here on epidermal peels of onion scales and celery epidermis cells which were sectioned for the AFM to visualize the inner surface (closest to the plasma membrane) of the outer epidermal wall. The nm-wide cellulose microfibrils orientation and multilayer structure were clearly observed. The microfibril orientation and alignment tend to be more organized in older scales compared with younger scales. The onion epidermis cell wall was also used as a test analog to study cell wall elasticity by the AFM nanoindentation and the SAM V(z) feature. The novelty in this work was to demonstrate the capability of these two techniques to analyze isolated, single layered plant cell walls in their natural state. AFM nanoindentation was also used to probe the effects of Ethylenediaminetetraacetic acid (EDTA), and calcium ion treatment to modify pectin networks in cell walls. The results suggest a significant modulus increase in the calcium ion treatment and a slight decrease in EDTA treatment. To complement the AFM measurements, the HF-SAM was used to obtain the V(z) signatures of the onion epidermis. These measurements were focused on documenting the effect of pectinase enzyme treatment. The results indicate a significant change in the V(z) signature curves with time into the enzyme treatment. Thus AFM and HF-SAM open the door to a systematic nondestructive structure and mechanical property

Measuring protein isoelectric points by AFM-based force spectroscopy using trace amounts of sample

Science.gov (United States)

Guo, Shifeng; Zhu, Xiaoying; Jańczewski, Dominik; Lee, Serina Siew Chen; He, Tao; Teo, Serena Lay Ming; Vancso, G. Julius

2016-09-01

Protein charge at various pH and isoelectric point (pI) values is important in understanding protein function. However, often only trace amounts of unknown proteins are available and pI measurements cannot be obtained using conventional methods. Here, we show a method based on the atomic force microscope (AFM) to determine pI using minute quantities of proteins. The protein of interest is immobilized on AFM colloidal probes and the adhesion force of the protein is measured against a positively and a negatively charged substrate made by layer-by-layer deposition of polyelectrolytes. From the AFM force-distance curves, pI values with an estimated accuracy of ±0.25 were obtained for bovine serum albumin, myoglobin, fibrinogen and ribonuclease A over a range of 4.7-9.8. Using this method, we show that the pI of the ‘footprint’ of the temporary adhesive proteins secreted by the barnacle cyprid larvae of Amphibalanus amphitrite is in the range 9.6-9.7.

Soft colloidal probes for AFM force measurements between water droplets in oil

KAUST Repository

Vakarelski, Ivan Uriev; Li, Erqiang; Thoroddsen, Sigurdur T

2014-01-01

Here we introduce an extension of the atomic force microscopy (AFM) colloidal probe technique, as a simple and reliable experimental approach to measure the interaction forces between small water droplets (~80-160. μm) dispersed in oil. Small water droplets are formed by capillary breakup of a microscale water jet in air, which is forced out of a fine capillary nozzle, and deposited on a superhydrophobic substrate immersed in tetradecane oil medium. In these conditions the water droplets are very loosely attached to the superhydrophobic substrate and are easily picked up with a hydrophobic AFM cantilever to form a soft colloidal probe. Sample force measurements are conducted to demonstrate the capability of the technique.

Soft colloidal probes for AFM force measurements between water droplets in oil

KAUST Repository

Vakarelski, Ivan Uriev

2014-11-01

Here we introduce an extension of the atomic force microscopy (AFM) colloidal probe technique, as a simple and reliable experimental approach to measure the interaction forces between small water droplets (~80-160. μm) dispersed in oil. Small water droplets are formed by capillary breakup of a microscale water jet in air, which is forced out of a fine capillary nozzle, and deposited on a superhydrophobic substrate immersed in tetradecane oil medium. In these conditions the water droplets are very loosely attached to the superhydrophobic substrate and are easily picked up with a hydrophobic AFM cantilever to form a soft colloidal probe. Sample force measurements are conducted to demonstrate the capability of the technique.

Characterization of deep nanoscale surface trenches with AFM using thin carbon nanotube probes in amplitude-modulation and frequency-force-modulation modes

International Nuclear Information System (INIS)

Solares, Santiago D

2008-01-01

The characterization of deep surface trenches with atomic force microscopy (AFM) presents significant challenges due to the sharp step edges that disturb the instrument and prevent it from faithfully reproducing the sample topography. Previous authors have developed AFM methodologies to successfully characterize semiconductor surface trenches with dimensions on the order of tens of nanometers. However, the study of imaging fidelity for features with dimensions smaller than 10 nm has not yet received sufficient attention. Such a study is necessary because small features in some cases lead to apparently high-quality images that are distorted due to tip and sample mechanical deformation. This paper presents multi-scale simulations, illustrating common artifacts affecting images of nanoscale trenches taken with fine carbon nanotube probes within amplitude-modulation and frequency-force-modulation AFM (AM-AFM and FFM-AFM, respectively). It also describes a methodology combining FFM-AFM with a step-in/step-out algorithm analogous to that developed by other groups for larger trenches, which can eliminate the observed artifacts. Finally, an overview of the AFM simulation methods is provided. These methods, based on atomistic and continuum simulation, have been previously used to study a variety of samples including silicon surfaces, carbon nanotubes and biomolecules

Gum tragacanth stabilized green gold nanoparticles as cargos for Naringin loading: A morphological investigation through AFM.

Science.gov (United States)

Rao, Komal; Imran, Muhammad; Jabri, Tooba; Ali, Imdad; Perveen, Samina; Shafiullah; Ahmed, Shakil; Shah, Muhammad Raza

2017-10-15

Gold nanoparticles (AuNPs) have attracted greater scientific interests for the construction of drugs loading cargos due to their biocompatibility, safety and facile surface modifications. This study deals with the fabrication of gum tragacanth (GT) green AuNPs as carrier for Naringin, a less water soluble therapeutic molecule. The optimized AuNPs were characterized through UV-vis spectroscopy, FT-IR and atomic force microscope (AFM). Naringin loaded nanoparticles were investigated for their bactericidal potentials using Tetrazolium Microplate assay. Morphological studies conducted via AFM revealed spherical shape for AuNPs with nano-range size and stabilized by GT multi-functional groups. The AuNPs acted as carrier for increased amount of Naringin. Upon loading in AuNPs, Naringin An increased in the bactericidal potentials of Naringin was observed after loading on AuNPs against various tested bacterial strains. This was further authenticated by the surface morphological analysis, showing enhanced membrane destabilizing effects of loaded Naringin. The results suggest that GT stabilized green AuNPs can act as effective delivery vehicles for enhancing bactericidal potentials of Naringin. Copyright © 2017 Elsevier Ltd. All rights reserved.

Data from quantitative label free proteomics analysis of rat spleen

Directory of Open Access Journals (Sweden)

Khadar Dudekula

2016-09-01

Full Text Available The dataset presented in this work has been obtained using a label-free quantitative proteomic analysis of rat spleen. A robust method for extraction of proteins from rat spleen tissue and LC-MS-MS analysis was developed using a urea and SDS-based buffer. Different fractionation methods were compared. A total of 3484 different proteins were identified from the pool of all experiments run in this study (a total of 2460 proteins with at least two peptides. A total of 1822 proteins were identified from nine non-fractionated pulse gels, 2288 proteins and 2864 proteins were identified by SDS-PAGE fractionation into three and five fractions respectively. The proteomics data are deposited in ProteomeXchange Consortium via PRIDE PXD003520, Progenesis and Maxquant output are presented in the supported information. The generated list of proteins under different regimes of fractionation allow assessing the nature of the identified proteins; variability in the quantitative analysis associated with the different sampling strategy and allow defining a proper number of replicates for future quantitative analysis. Keywords: Spleen, Rat, Protein extraction, Label-free quantitative proteomics

Quantitative data analysis in education a critical introduction using SPSS

CERN Document Server

Connolly, Paul

2007-01-01

This book provides a refreshing and user-friendly guide to quantitative data analysis in education for students and researchers. It assumes absolutely no prior knowledge of quantitative methods or statistics. Beginning with the very basics, it provides the reader with the knowledge and skills necessary to be able to undertake routine quantitative data analysis to a level expected of published research. Rather than focusing on teaching statistics through mathematical formulae, the book places an emphasis on using SPSS to gain a real feel for the data and an intuitive grasp of t

Quantitative analysis of mechanical and electrostatic properties of poly(lactic) acid fibers and poly(lactic) acid—carbon nanotube composites using atomic force microscopy

International Nuclear Information System (INIS)

Iqbal, Qais; Bernstein, Peter; Zhu, Yazhe; Rahamim, Joseph; Cebe, Peggy; Staii, Cristian

2015-01-01

We use atomic force microscopy (AFM) to perform a systematic quantitative characterization of the elastic modulus and dielectric constant of poly(L-lactic acid) electrospun nanofibers (PLLA), as well as composites of PLLA fibers with 1.0 wt% embedded multiwall carbon nanotubes (MWCNTs–PLLA). The elastic moduli are measured in the fiber skin region via AFM nanoindentation, and the dielectric constants are determined by measuring the phase shifts obtained via electrostatic force microscopy (EFM). We find that the average value for the elastic modulus for PLLA fibers is (9.8 ± 0.9) GPa, which is a factor of 2 larger than the measured average elastic modulus for MWCNT–PLLA composites (4.1 ± 0.7) GPa. We also use EFM to measure dielectric constants for both types of fibers. These measurements show that the dielectric constants of the MWCNT–PLLA fibers are significantly larger than the corresponding values obtained for PLLA fiber. This result is consistent with the higher polarizability of the MWCNT–PLLA composites. The measurement methods presented are general, and can be applied to determine the mechanical and electrical properties of other polymers and polymer nanocomposites. (paper)

Quantitative analysis method for ship construction quality

Directory of Open Access Journals (Sweden)

FU Senzong

2017-03-01

Full Text Available The excellent performance of a ship is assured by the accurate evaluation of its construction quality. For a long time, research into the construction quality of ships has mainly focused on qualitative analysis due to a shortage of process data, which results from limited samples, varied process types and non-standardized processes. Aiming at predicting and controlling the influence of the construction process on the construction quality of ships, this article proposes a reliability quantitative analysis flow path for the ship construction process and fuzzy calculation method. Based on the process-quality factor model proposed by the Function-Oriented Quality Control (FOQC method, we combine fuzzy mathematics with the expert grading method to deduce formulations calculating the fuzzy process reliability of the ordinal connection model, series connection model and mixed connection model. The quantitative analysis method is applied in analyzing the process reliability of a ship's shaft gear box installation, which proves the applicability and effectiveness of the method. The analysis results can be a useful reference for setting key quality inspection points and optimizing key processes.

EUV blank defect and particle inspection with high throughput immersion AFM with 1nm 3D resolution

NARCIS (Netherlands)

Es, M.H. van; Sadeghian Marnani, H.

2016-01-01

Inspection of EUV mask substrates and blanks is demanding. We envision this is a good target application for massively parallel Atomic Force Microscopy (AFM). We envision to do a full surface characterization of EUV masks with AFM enabling 1nm true 3D resolution over the entire surface. The limiting

Quantitative X-ray analysis of pigments

International Nuclear Information System (INIS)

Araujo, M. Marrocos de

1987-01-01

The 'matrix-flushing' and the 'adiabatic principle' methods have been applied for the quantitative analysis through X-ray diffraction patterns of pigments and extenders mixtures, frequently used in paint industry. The results obtained have shown the usefulness of these methods, but still ask for improving their accuracy. (Author) [pt

High Resolution and Differential PIXE combined with RBS, EBS and AFM analysis of magnesium titanate (MgTiO3) multilayer structures

International Nuclear Information System (INIS)

Reis, M.A.; Alves, L.C.; Barradas, N.P.; Chaves, P.C.; Nunes, B.; Taborda, A.; Surendran, K.P.; Wu, A.; Vilarinho, P.M.; Alves, E.

2010-01-01

Thorough structural characterization of deep laying thin film, including the inference of interdiffusion profiles is frequently a complex problem. The use of RBS/PIXE holistic approaches, already shown to represent a powerful method, sometimes faces difficulties if standard experimental procedures are used. In this work, following a series of 4 He Rutherford backscattering and 1 H elastic backscattering experiments, carried out to study the influence of SrTiO 3 as a possible cladding layer between Pt/TiO 2 /SiO 2 /(1 0 0)Si substrates and MgTiO 3 films, a simple holistic RBS-PIXE is shown to be not enough for the solution of such a problem. Establishing of the Sr depth profile, was only possible after AFM, High-Resolution EDS PIXE and differential PIXE analysis were carried out. Results, problems faced and conclusions obtained are presented.

Novel approach in quantitative analysis of shearography method

International Nuclear Information System (INIS)

Wan Saffiey Wan Abdullah

2002-01-01

The application of laser interferometry in industrial non-destructive testing and material characterization is becoming more prevalent since this method provides non-contact full-field inspection of the test object. However their application only limited to the qualitative analysis, current trend has changed to the development of this method by the introduction of quantitative analysis, which attempts to detail the defect examined. This being the design feature for a ranges of object size to be examined. The growing commercial demand for quantitative analysis for NDT and material characterization is determining the quality of optical and analysis instrument. However very little attention is currently being paid to understanding, quantifying and compensating for the numerous error sources which are a function of interferometers. This paper presents a comparison of measurement analysis using the established theoretical approach and the new approach, taken into account the factor of divergence illumination and other geometrical factors. The difference in the measurement system could be associated in the error factor. (Author)

Measurement of nanosize etched pits in SiO2 optical fiber conduit using AFM

International Nuclear Information System (INIS)

Espinosa, G.; Golzarri, J.I.; Vazquez, C.; Fragoso, R.

2003-01-01

Fission fragment tracks from 252 Cf have been observed in SiO 2 optical fiber, using an atomic force microscope (AFM), after a very short chemical etching in hydrofluoric acid solution at normal temperature. The nuclear track starting and evolution process is followed by the AFM direct measurements on the material surface and beyond a fine layer of the surface material. The images of the scanned cones were determined observing the two predominant energies from 252 Cf fission fragments and the development of the tracks in the 150 μm diameter optical fiber conduit

A novel dog-bone oscillating AFM probe with thermal actuation and piezoresistive detection.

Science.gov (United States)

Xiong, Zhuang; Mairiaux, Estelle; Walter, Benjamin; Faucher, Marc; Buchaillot, Lionel; Legrand, Bernard

2014-10-31

In order to effectively increase the resonance frequency and the quality factor of atomic force microscope (AFM) probes, a novel oscillating probe based on a dog-bone shaped MEMS resonator was conceived, designed, fabricated and evaluated. The novel probe with 400 μm in length, 100 μm in width and 5 μm in thickness was enabled to feature MHz resonance frequencies with integrated thermal actuation and piezoresistive detection. Standard silicon micromachining was employed. Both electrical and optical measurements were carried out in air. The resonance frequency and the quality factor of the novel probe were measured to be 5.4 MHz and 4000 respectively, which are much higher than those (about several hundreds of kHz) of commonly used cantilever probes. The probe was mounted onto a commercial AFM set-up through a dedicated probe-holder and circuit board. Topographic images of patterned resist samples were obtained. It is expected that the resonance frequency and the measurement bandwidth of such probes will be further increased by a proper downscaling, thus leading to a significant increase in the scanning speed capability of AFM instruments.

On the nonlinear dynamics of trolling-mode AFM: Analytical solution using multiple time scales method

Science.gov (United States)

Sajjadi, Mohammadreza; Pishkenari, Hossein Nejat; Vossoughi, Gholamreza

2018-06-01

Trolling mode atomic force microscopy (TR-AFM) has resolved many imaging problems by a considerable reduction of the liquid-resonator interaction forces in liquid environments. The present study develops a nonlinear model of the meniscus force exerted to the nanoneedle of TR-AFM and presents an analytical solution to the distributed-parameter model of TR-AFM resonator utilizing multiple time scales (MTS) method. Based on the developed analytical solution, the frequency-response curves of the resonator operation in air and liquid (for different penetration length of the nanoneedle) are obtained. The closed-form analytical solution and the frequency-response curves are validated by the comparison with both the finite element solution of the main partial differential equations and the experimental observations. The effect of excitation angle of the resonator on horizontal oscillation of the probe tip and the effect of different parameters on the frequency-response of the system are investigated.

Electrostatic nanopatterning of PMMA by AFM charge writing for directed nano-assembly

International Nuclear Information System (INIS)

Ressier, L; Nader, V Le

2008-01-01

Electrostatic nanopatterning of poly(methylmethacrylate) (PMMA) thin films by atomic force microscopy (AFM) charge writing was investigated using Kelvin force microscopy (KFM). The lateral size of the electrostatic patterns and the amount of injected charges are closely correlated and can be controlled by the height of the voltage pulses applied to the AFM tip and the tip-sample separation during the writing process. Charge retention measurements show that PMMA has excellent charge storage properties in air under relative humidities from 1% to 60% and withstands immersion in ultra-pure water. This study thus reveals that PMMA is a very promising electret to create efficient electrostatic nanopatterns for directed self-assembly of nanoscale objects, including the broad range of colloidal particles or molecules in aqueous solutions

Influence of smectite suspension structure on sheet orientation in dry sediments: XRD and AFM applications.

Science.gov (United States)

Zbik, Marek S; Frost, Ray L

2010-06-15

The structure-building phenomena within clay aggregates are governed by forces acting between clay particles. Measurements of such forces are important to understand in order to manipulate the aggregate structure for applications such as dewatering of mineral processing tailings. A parallel particle orientation is required when conducting XRD investigation on the oriented samples and conduct force measurements acting between basal planes of clay mineral platelets using atomic force microscopy (AFM). To investigate how smectite clay platelets were oriented on silicon wafer substrate when dried from suspension range of methods like SEM, XRD and AFM were employed. From these investigations, we conclude that high clay concentrations and larger particle diameters (up to 5 microm) in suspension result in random orientation of platelets in the substrate. The best possible laminar orientation in the clay dry film, represented in the XRD 001/020 intensity ratio of 47 was obtained by drying thin layers from 0.02 wt.% clay suspensions of the natural pH. Conducted AFM investigations show that smectite studied in water based electrolytes show very long-range repulsive forces lower in strength than electrostatic forces from double-layer repulsion. It was suggested that these forces may have structural nature. Smectite surface layers rehydrate in water environment forms surface gel with spongy and cellular texture which cushion approaching AFM probe. This structural effect can be measured in distances larger than 1000 nm from substrate surface and when probe penetrate this gel layer, structural linkages are forming between substrate and clay covered probe. These linkages prevent subsequently smooth detachments of AFM probe on way back when retrieval. This effect of tearing new formed structure apart involves larger adhesion-like forces measured in retrieval. It is also suggested that these effect may be enhanced by the nano-clay particles interaction. 2010 Elsevier Inc. All

Assembly of live micro-organisms on microstructured PDMS stamps by convective/capillary deposition for AFM bio-experiments

International Nuclear Information System (INIS)

Dague, E; Jauvert, E; Laplatine, L; Thibault, C; Viallet, B; Ressier, L

2011-01-01

Immobilization of live micro-organisms on solid substrates is an important prerequisite for atomic force microscopy (AFM) bio-experiments. The method employed must immobilize the cells firmly enough to enable them to withstand the lateral friction forces exerted by the tip during scanning but without denaturing the cell interface. In this work, a generic method for the assembly of living cells on specific areas of substrates is proposed. It consists in assembling the living cells within the patterns of microstructured, functionalized poly-dimethylsiloxane (PDMS) stamps using convective/capillary deposition. This versatile approach is validated by applying it to two systems of foremost importance in biotechnology and medicine: Saccharomyces cerevisiae yeasts and Aspergillus fumigatus fungal spores. We show that this method allows multiplexing AFM nanomechanical measurements by force spectroscopy on S. cerevisiae yeasts and high-resolution AFM imaging of germinated Aspergillus conidia in buffer medium. These two examples clearly demonstrate the immense potential of micro-organism assembly on functionalized, microstructured PDMS stamps by convective/capillary deposition for performing rigorous AFM bio-experiments on living cells.

SU-8 hollow cantilevers for AFM cell adhesion studies

Science.gov (United States)

Martinez, Vincent; Behr, Pascal; Drechsler, Ute; Polesel-Maris, Jérôme; Potthoff, Eva; Vörös, Janos; Zambelli, Tomaso

2016-05-01

A novel fabrication method was established to produce flexible, transparent, and robust tipless hollow atomic force microscopy (AFM) cantilevers made entirely from SU-8. Channels of 3 μm thickness and several millimeters length were integrated into 12 μm thick and 40 μm wide cantilevers. Connected to a pressure controller, the devices showed high sealing performance with no leakage up to 6 bars. Changing the cantilever lengths from 100 μm to 500 μm among the same wafer allowed the targeting of various spring constants ranging from 0.5 to 80 N m-1 within a single fabrication run. These hollow polymeric AFM cantilevers were operated in the optical beam deflection configuration. To demonstrate the performance of the device, single-cell force spectroscopy experiments were performed with a single probe detaching in a serial protocol more than 100 Saccharomyces cerevisiae yeast cells from plain glass and glass coated with polydopamine while measuring adhesion forces in the sub-nanoNewton range. SU-8 now offers a new alternative to conventional silicon-based hollow cantilevers with more flexibility in terms of complex geometric design and surface chemistry modification.

SU-8 hollow cantilevers for AFM cell adhesion studies

International Nuclear Information System (INIS)

Martinez, Vincent; Behr, Pascal; Vörös, Janos; Zambelli, Tomaso; Drechsler, Ute; Polesel-Maris, Jérôme; Potthoff, Eva

2016-01-01

A novel fabrication method was established to produce flexible, transparent, and robust tipless hollow atomic force microscopy (AFM) cantilevers made entirely from SU-8. Channels of 3 μm thickness and several millimeters length were integrated into 12 μm thick and 40 μm wide cantilevers. Connected to a pressure controller, the devices showed high sealing performance with no leakage up to 6 bars. Changing the cantilever lengths from 100 μm to 500 μm among the same wafer allowed the targeting of various spring constants ranging from 0.5 to 80 N m −1 within a single fabrication run. These hollow polymeric AFM cantilevers were operated in the optical beam deflection configuration. To demonstrate the performance of the device, single-cell force spectroscopy experiments were performed with a single probe detaching in a serial protocol more than 100 Saccharomyces cerevisiae yeast cells from plain glass and glass coated with polydopamine while measuring adhesion forces in the sub-nanoNewton range. SU-8 now offers a new alternative to conventional silicon-based hollow cantilevers with more flexibility in terms of complex geometric design and surface chemistry modification. (paper)

Magnetotransport measurements on AFM structured two-dimensional electron gases on cleaved edges of GaAs/AlGaAs; Magnetotransportmessungen an AFM-strukturierten zweidimensionalen Elektronengasen auf GaAs/AlGaAs-Spaltkanten

Energy Technology Data Exchange (ETDEWEB)

Reinwald, Elisabeth

2009-06-25

In this thesis a two dimensional electron gas (2DEG) on a (110) cleavage plane of a GaAs/AlGaAs(001) heterostructure was produced by means of cleaved edge overgrowth (CEO) and modulated in two dimensions. The 2DEG was modulated in one direction by a superlattice of the subjacent GaAs/AlGaAs(001) heterostructure. A second modulation, perpendicular to the first was realized by local anodic oxidation (LAO) with an atomic force microscope (AFM). For the process of LAO an electric voltage is applied between the tip of the AFM and the surface of the GaAs. The natural water film on the surface acts as electrolyte so that the GaAs surface is locally oxidized underneath the AFM tip. This oxide leads to a band bending so that the 2DEG underneath the oxide is locally depleted. On these systems magnetotransport measurements revealed that it is actually possible to modulate 2DEGs on a sufficient large area by local anodic oxidation. On the cleaved surfaces the influence of the two dimensional modulation on the electron gas has been demonstrated. (orig.)

Statistical flaw strength distributions for glass fibres: Correlation between bundle test and AFM-derived flaw size density functions

International Nuclear Information System (INIS)

Foray, G.; Descamps-Mandine, A.; R’Mili, M.; Lamon, J.

2012-01-01

The present paper investigates glass fibre flaw size distributions. Two commercial fibre grades (HP and HD) mainly used in cement-based composite reinforcement were studied. Glass fibre fractography is a difficult and time consuming exercise, and thus is seldom carried out. An approach based on tensile tests on multifilament bundles and examination of the fibre surface by atomic force microscopy (AFM) was used. Bundles of more than 500 single filaments each were tested. Thus a statistically significant database of failure data was built up for the HP and HD glass fibres. Gaussian flaw distributions were derived from the filament tensile strength data or extracted from the AFM images. The two distributions were compared. Defect sizes computed from raw AFM images agreed reasonably well with those derived from tensile strength data. Finally, the pertinence of a Gaussian distribution was discussed. The alternative Pareto distribution provided a fair approximation when dealing with AFM flaw size.

Quantitative methods for the analysis of electron microscope images

DEFF Research Database (Denmark)

Skands, Peter Ulrik Vallø

1996-01-01

The topic of this thesis is an general introduction to quantitative methods for the analysis of digital microscope images. The images presented are primarily been acquired from Scanning Electron Microscopes (SEM) and interfermeter microscopes (IFM). The topic is approached though several examples...... foundation of the thesis fall in the areas of: 1) Mathematical Morphology; 2) Distance transforms and applications; and 3) Fractal geometry. Image analysis opens in general the possibility of a quantitative and statistical well founded measurement of digital microscope images. Herein lies also the conditions...

Parameter determination for quantitative PIXE analysis using genetic algorithms

International Nuclear Information System (INIS)

Aspiazu, J.; Belmont-Moreno, E.

1996-01-01

For biological and environmental samples, PIXE technique is in particular advantage for elemental analysis, but the quantitative analysis implies accomplishing complex calculations that require the knowledge of more than a dozen parameters. Using a genetic algorithm, the authors give here an account of the procedure to obtain the best values for the parameters necessary to fit the efficiency for a X-ray detector. The values for some variables involved in quantitative PIXE analysis, were manipulated in a similar way as the genetic information is treated in a biological process. The authors carried out the algorithm until they reproduce, within the confidence interval, the elemental concentrations corresponding to a reference material

Mechanism of high-resolution STM/AFM imaging with functionalized tips

Czech Academy of Sciences Publication Activity Database

Hapala, Prokop; Kichin, G.; Wagner, C.; Tautz, F.S.; Temirov, R.; Jelínek, Pavel

2014-01-01

Roč. 90, č. 8 (2014), "085421-1"-"085421-9" ISSN 1098-0121 R&D Projects: GA ČR(CZ) GC14-16963J Grant - others:AVČR(CZ) M100101207 Institutional support: RVO:68378271 Keywords : AFM * STM * high resolution Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 3.736, year: 2014

Measuring the force of single protein molecule detachment from surfaces with AFM.

Science.gov (United States)

Tsapikouni, Theodora S; Missirlis, Yannis F

2010-01-01

Atomic force microscopy (AFM) was used to measure the non-specific detachment force of single fibrinogen molecules from glass surfaces. The identification of single unbinding events was based on the characteristics of the parabolic curves, recorded during the stretching of protein molecules. Fibrinogen molecules were covalently bound to Si(3)N(4) AFM tips, previously modified with 3-aminopropyl-dimethyl-ethoxysilane, through a homobifunctional poly(ethylene glycol) linker bearing two hydroxysulfosuccinimide esters. The most probable detachment force was found to be 210 pN, when the tip was retracting with a velocity of 1400 nm/s, while the distribution of the detachment distances indicated that the fibrinogen chain can be elongated beyond the length of the physical conformation before detachment. The dependence of the most probable detachment force on the loading rate was examined and the dynamics of fibrinogen binding to the surface were found amenable to the simple expression of the Bell-Evans theory. The theory's expansion, however, by incorporating the concept of the rupture of parallel residue-surface bonds could only describe the detachment of fibrinogen for a small number of such bonds. Finally, the mathematical expression of the Worm-Like Chain model was used to fit the stretching curves before rupture and two interpretations are suggested for the description of the AFM curves with multiple detachment events.

Quantitative morphological and compositional evaluation of laboratory prepared aluminoborosilicate glass surfaces

Energy Technology Data Exchange (ETDEWEB)

Gong, Yuxuan, E-mail: yg4@alfred.edu; Wren, Anthony W.; Mellott, Nathan P.

2015-01-01

Graphical abstract: - Highlights: • Aluminoborosilicate glass surfaces were prepared through both melting and polishing/etching and the surface composition and morphology were quantified as a function of processing method. • Glass surface morphology was quantified using PSD analysis, followed by both fractal and ABC model fitting, resulting in a comprehensive description of the spatial distribution of roughness. • All melt surfaces showed a depletion in Na, Ca, and B with respect to the bulk composition. Polished/etched surfaces showed a depletion in Na, B, and Al with respect to the bulk composition. • It was found that increasing heat treatment temperature of melt surfaces lead to a decrease in equivalent roughness and an increased spatial homogeneity of roughness while etching of polished ISG glass surfaces decreases the roughness and spatial distribution homogeneity of roughness. - Abstract: Surface finishing techniques including polishing, etching and heat treatment can modify the topography and the surface chemical composition of glasses. It is widely acknowledged that atomic force microscopy (AFM) can be used to quantify the morphology of surfaces, providing various parameters including average, peak-to-valley, and apparent root-mean-square roughness. Furthermore advanced power spectral density (PSD) analysis of AFM-derived surface profiles offers quantification of the spatial homogeneity of roughness values along different wavelengths, resulting in parameters including equivalent RMS, Hurst exponent, and fractal dimension. Outermost surface (∼8 nm) chemical composition can be quantitatively measured by X-ray photoelectron spectroscopy. In this paper, we first developed a series of surface finishing methods for an aluminoborosilicate glass system by polishing, etching or heat treatment. The chemical composition and environment of prepared glass surfaces were quantified by XPS and topographical analysis was carried out by fractal and k

AFM topographies of densely packed nanoparticles: a quick way to determine the lateral size distribution by autocorrelation function analysis

Czech Academy of Sciences Publication Activity Database

Fekete, Ladislav; Kůsová, Kateřina; Petrák, Václav; Kratochvílová, Irena

2012-01-01

Roč. 14, č. 8 (2012), s. 1-10 ISSN 1388-0764 R&D Projects: GA AV ČR KAN200100801; GA TA ČR TA01011165; GA ČR(CZ) GAP304/10/1951; GA ČR GPP204/12/P235 Institutional research plan: CEZ:AV0Z10100520 Keywords : lateral grain size distribution * AFM * autocorrelation function * nanodiamond Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 2.175, year: 2012

Characteristics of a single-channel superconducting flux flow transistor fabricated by an AFM modification technique

Energy Technology Data Exchange (ETDEWEB)

Ko, Seokcheol [Jeonnam Regional Innovation Agency, 1000 Namak-Ri, Samhyang-Myun, Muan-Gun, Jeollanam-Do 534-700 (Korea, Republic of)], E-mail: suntrac@jina.re.kr; Kim, Seong-Jong [Mokpo Maritime University, Chukkyo-Dong, Mokpo City, Cheonnam 530-729 (Korea, Republic of)

2007-11-01

The demand for high performance, integrity, and miniaturization in the area of electronic and mechanic devices has drawn interest in the fabrication of nanostructures. However, it is difficult to fabricate the channel with nano-scale using a conventional photography techniques. AFM anodization technique is a maskless process and effective method to overcome the difficulty in fabricating a nano-scale channel. In this paper, we first present a new fabrication of a single-channel SFFT using a selective oxidation process induced by an AFM probe. The modified channel was investigated by electron probe microanalyzer (EPMA) to find the compositional variation of the transformed region. In order to confirm the operation of a single-channel SFFT, we measured the voltage-current characteristics at the temperature of liquid nitrogen by an I-V automatic measurement system. Our results indicate that the single-channel SFFT having effect as a weak link is effectively fabricated by an AFM lithography process.

Characteristics of a single-channel superconducting flux flow transistor fabricated by an AFM modification technique

International Nuclear Information System (INIS)

Ko, Seokcheol; Kim, Seong-Jong

2007-01-01

The demand for high performance, integrity, and miniaturization in the area of electronic and mechanic devices has drawn interest in the fabrication of nanostructures. However, it is difficult to fabricate the channel with nano-scale using a conventional photography techniques. AFM anodization technique is a maskless process and effective method to overcome the difficulty in fabricating a nano-scale channel. In this paper, we first present a new fabrication of a single-channel SFFT using a selective oxidation process induced by an AFM probe. The modified channel was investigated by electron probe microanalyzer (EPMA) to find the compositional variation of the transformed region. In order to confirm the operation of a single-channel SFFT, we measured the voltage-current characteristics at the temperature of liquid nitrogen by an I-V automatic measurement system. Our results indicate that the single-channel SFFT having effect as a weak link is effectively fabricated by an AFM lithography process

The substructure of immunoglobulin G resolved to 25 kDa using amplitude modulation AFM in air

International Nuclear Information System (INIS)

Thomson, Neil H.

2005-01-01

Amplitude modulation (or tapping-mode) atomic force microscopy (AM AFM or TM AFM) in air can reveal sub-molecular details of isolated multi-subunit proteins, such as immunoglobulin G (IgG) antibodies, on atomically flat support surfaces such as mica [A. San Paulo, R. Garcia, Biophys. J. 78(3) (2000) 1599]. This is achieved by controlling the microscope imaging parameters (e.g. cantilever drive frequency and set-point amplitude) to keep the AFM tip predominantly in the attractive force regime. Under these conditions, the 50 kDa F c and F ab subunits can be resolved when the molecule has the appropriate orientation on the surface. The presence of a water layer on hydrophilic mica is an important factor affecting imaging contrast, a consequence of capillary neck formation between tip and surface [L. Zitzler, S. Herminghaus, F. Mugele, Phys. Rev. B 66(15) (2002) 155436]. Desiccation of samples to remove surface bound water layers can yield reproducible imaging of the IgG substructure [N.H. Thomson, J. Microsc. (Oxford) 217(3) (2004) 193]. This approach has also given higher resolution than previously achieved, down to about 25 kDa, and these data are detailed here. These subdomains are formed as two immunoglobulin folds from the light and heavy peptide chains of the IgG crossover. This result has been validated by comparing the AFM images with X-ray crystallography data from the protein data bank. These data show that the AFM can obtain 25 kDa resolution on isolated protein molecules with commercially available silicon tips, but, as expected for a local probe technique, resolution is highly dependent on the macromolecular orientation on the support surface

Enhancing local absorption within a gold nano-sphere on a dielectric surface under an AFM probe

International Nuclear Information System (INIS)

Talebi Moghaddam, Sina; Ertürk, Hakan; Mengüç, M. Pınar

2016-01-01

This study considers enhancing localized absorption by a gold nanoparticle (NP) placed over a substrate where an atomic force microscope (AFM) tip is in close proximity of the particle. The gold NP and AFM tip are interacting with a surface evanescent wave, resulting a near-field coupling between the tip and NP and consequently enhances the absorption. This concept can be used for selective heating of NPs placed over a surface that enables precise manufacturing at nanometer scales. Different tip positions are considered to identify the optimal tip location and the corresponding enhancement limits. The effects of these interactions on the absorption profiles of dielectric core/gold shell NPs are also studied. It is observed that using core–shell nanoparticles with a dielectric core leads to further enhancement of the absorption efficiency and a more uniform distribution of absorption over the shell. Discrete dipole approximation coupled with surface interactions (DDA-SI) is employed throughout the study, and it is vectorized to improve its computational efficiency. - Highlights: • Plasmonic coupling between solid or core-shell nanoparticles, dielectric surface and Si AFM tip is investigated for achieving localized heating for nano-manufacturing. • Absorption efficiency enhancement limits for core-shell and solid nanoparticles are identified using an AFM tip for surface evanescent wave heating. • The effect of tip location, relative to surface wave direction is outlined, identifying optimal locations, and heat absorption distribution over core-shell and solid nanoparticles. • While using a Si AFM tip enhances absorption, using a dielectric core result in further enhancement in absorption with a more uniform distribution. • DDA-SI-v developed by vectorizing the formulations of DDA-SI for improved computational efficiency.

Application of AFM in microscopy and fabrication of micro/nanostructures

Czech Academy of Sciences Publication Activity Database

Lopour, F.; Kalousek, R.; Škoda, D.; Spousta, J.; Matějka, František; Šikola, T.

2002-01-01

Roč. 34, č. 1 (2002), s. 352 - 355 ISSN 0142-2421 R&D Projects: GA MŠk ME 334; GA MŠk ME 480 Institutional research plan: CEZ:AV0Z2065902 Keywords : AFM fabrication * local anodic oxidation * oxide nanostructures Subject RIV: JA - Electronics ; Optoelectronics, Electrical Engineering Impact factor: 1.071, year: 2002

SEM and AFM studies of dip-coated CuO nanofilms.

Science.gov (United States)

Dhanasekaran, V; Mahalingam, T; Ganesan, V

2013-01-01

Cupric oxide (CuO) semiconducting thin films were prepared at various copper sulfate concentrations by dip coating. The copper sulfate concentration was varied to yield films of thicknesses in the range of 445-685 nm by surface profilometer. X-ray diffraction patterns revealed that the deposited films were polycrystalline in nature with monoclinic structure of (-111) plane. The surface morphology and topography of monoclinic-phase CuO thin films were examined using scanning electron microscopy (SEM) and atomic force microscopy (AFM), respectively. Surface roughness profile was plotted using WSxM software and the estimated surface roughness was about ∼19.4 nm at 30 mM molar concentration. The nanosheets shaped grains were observed by SEM and AFM studies. The stoichiometric compound formation was observed at 30 mM copper sulfate concentration prepared film by EDX. The indirect band gap energy of CuO films was increased from 1.08 to 1.20 eV with the increase of copper sulfate concentrations. Copyright © 2012 Wiley Periodicals, Inc.

Force and Compliance Measurements on Living Cells Using Atomic Force Microscopy (AFM

Directory of Open Access Journals (Sweden)

Wojcikiewicz Ewa P.

2004-01-01

Full Text Available We describe the use of atomic force microscopy (AFM in studies of cell adhesion and cell compliance. Our studies use the interaction between leukocyte function associated antigen-1 (LFA-1/intercellular adhesion molecule-1 (ICAM-1 as a model system. The forces required to unbind a single LFA-1/ICAM-1 bond were measured at different loading rates. This data was used to determine the dynamic strength of the LFA-1/ICAM-1 complex and characterize the activation potential that this complex overcomes during its breakage. Force measurements acquired at the multiple- bond level provided insight about the mechanism of cell adhesion. In addition, the AFM was used as a microindenter to determine the mechanical properties of cells. The applications of these methods are described using data from a previous study.

Carbon nanotube/carbon nanotube composite AFM probes prepared using ion flux molding

Science.gov (United States)

Chesmore, Grace; Roque, Carrollyn; Barber, Richard

The performance of carbon nanotube-carbon nanotube composite (CNT/CNT composite) atomic force microscopy (AFM) probes is compared to that of conventional Si probes in AFM tapping mode. The ion flux molding (IFM) process, aiming an ion beam at the CNT probe, aligns the tip to a desired angle. The result is a relatively rigid tip that is oriented to offset the cantilever angle. Scans using these probes reveal an improvement in image accuracy over conventional tips, while allowing higher aspect ratio imaging of 3D surface features. Furthermore, the lifetimes of CNT-CNT composite tips are observed to be longer than both conventional tips and those claimed for other CNT technologies. Novel applications include the imaging of embiid silk. Supported by the Clare Boothe Luce Research Scholars Award and Carbon Design Innovations.

Quantitative analysis of γ-oryzanol content in cold pressed rice bran oil by TLC-image analysis method.

Science.gov (United States)

Sakunpak, Apirak; Suksaeree, Jirapornchai; Monton, Chaowalit; Pathompak, Pathamaporn; Kraisintu, Krisana

2014-02-01

To develop and validate an image analysis method for quantitative analysis of γ-oryzanol in cold pressed rice bran oil. TLC-densitometric and TLC-image analysis methods were developed, validated, and used for quantitative analysis of γ-oryzanol in cold pressed rice bran oil. The results obtained by these two different quantification methods were compared by paired t-test. Both assays provided good linearity, accuracy, reproducibility and selectivity for determination of γ-oryzanol. The TLC-densitometric and TLC-image analysis methods provided a similar reproducibility, accuracy and selectivity for the quantitative determination of γ-oryzanol in cold pressed rice bran oil. A statistical comparison of the quantitative determinations of γ-oryzanol in samples did not show any statistically significant difference between TLC-densitometric and TLC-image analysis methods. As both methods were found to be equal, they therefore can be used for the determination of γ-oryzanol in cold pressed rice bran oil.

A surface evolution scheme to identify nanoscale intrinsic geometry from AFM experimental data

International Nuclear Information System (INIS)

Jang, Hong-Lae; Kim, Hyun-Seok; Park, Youmie; Cho, Seonho

2013-01-01

The geometrical properties of metallic nanoparticles such as the size and morphology have significant impacts on the structure and stability of the adsorbed biological entities as well as the nanoscale structural performances. To identify the nanoscale intrinsic geometry from the height images by atomic force microscopy (AFM), we developed a curvature-dependent evolution scheme that can eliminate the noise and smoothen the surfaces. The principal curvatures are computed directly from the first and second derivatives of the discrete AFM height data. The principal curvatures and directions correspond to the eigenvalues and eigenvectors of shape operator matrix, respectively. The evolution equation using the principal curvature flows smoothens the images in the corresponding principal directions. For an idealized model, κ 2 flow successfully identifies the major valley lines to represent the boundary of nanoparticles without referring to the phase information, whereas the mean curvature flow eliminates all the minor ones leaving only the major feature of the boundary. To demonstrate the capability of noise removal, smoothing surfaces, the identification of ridge and valley lines, and the extraction of intrinsic geometry, the developed numerical scheme is applied to real AFM data that include the silver nanoparticles of 24 nm diameter and the gold nanoparticles of 33–56 nm diameters

Surface analysis of glass fibres using XPS and AFM: case study of glass fibres recovered from the glass fibre reinforced polymer using chemical recycling

Science.gov (United States)

Nzioka, A. M.; Kim, Y. J.

2018-01-01

In this study, we present the results of an experimental study of the use of the X-ray photoelectron spectroscopy (XPS) and atomic force microscopy (AFM) to characterise the coatings of the recovered E - glass fibres. The recovered E - glass fibres were obtained using chemical recycling process coupled with ultrasound cavitation. The objective of this study was to analyse the impact of chemical recycling and the ultrasound cavitation process on the sizing properties of the recovered fibres. We obtained the recovered fibres and sized using 1 wt% 3 - aminopropyltriethoxysilane (APS). Part of the sized fibres was washed with acetone and analysed all the sample fibres using AFM and XPS. Results showed the different composition of sizing after extraction using acetone. We compared the results of this study with that of virgin clean glass fibres.

Quantitative nanohistological investigation of scleroderma: an atomic force microscopy-based approach to disease characterization

Directory of Open Access Journals (Sweden)

Strange AP

2017-01-01

Full Text Available Adam P Strange,1 Sebastian Aguayo,1 Tarek Ahmed,1 Nicola Mordan,1 Richard Stratton,2 Stephen R Porter,3 Susan Parekh,4 Laurent Bozec1 1Department of Biomaterials and Tissue Engineering, UCL Eastman Dental Institute, 2Centre for Rheumatology and Connective Tissue Diseases, Royal Free Hospital, UCL Medical School, 3UCL Eastman Dental Institute, 4Department of Pediatrics, UCL Eastman Dental Institute, London, UK Abstract: Scleroderma (or systemic sclerosis, SSc is a disease caused by excess crosslinking of collagen. The skin stiffens and becomes painful, while internally, organ function can be compromised by the less elastic collagen. Diagnosis of SSc is often only possible in advanced cases by which treatment time is limited. A more detailed analysis of SSc may provide better future treatment options and information of disease progression. Recently, the histological stain picrosirius red showing collagen register has been combined with atomic force microscopy (AFM to study SSc. Skin from healthy individuals and SSc patients was biopsied, stained and studied using AFM. By investigating the crosslinking of collagen at a smaller hierarchical stage, the effects of SSc were more pronounced. Changes in morphology and Young’s elastic modulus were observed and quantified; giving rise to a novel technique, we have termed “quantitative nanohistology”. An increase in nanoscale stiffness in the collagen for SSc compared with healthy individuals was seen by a significant increase in the Young’s modulus profile for the collagen. These markers of stiffer collagen in SSc are similar to the symptoms experienced by patients, giving additional hope that in the future, nanohistology using AFM can be readily applied as a clinical tool, providing detailed information of the state of collagen. Keywords: rheumatology, adjunct diagnosis, picrosirius red, collagen, nanohistology

Quantitative scenario analysis of low and intermediate level radioactive repository

International Nuclear Information System (INIS)

Lee, Keon Jae; Lee, Sang Yoon; Park, Keon Baek; Song, Min Cheon; Lee, Ho Jin

1998-03-01

Derivation of hypothetical radioactive waste disposal facility os conducted through sub-component characteristic analysis and conceptual modeling. It is studied that quantitative analysis of constructed scenario in terms of annual effective dose equivalent. This study is sequentially conducted according to performance assessment of radioactive waste disposal facility such as : ground water flow analysis, source term analysis, ground water transport, surface water transport, dose and pathways. The routine program module such as VAM2D-PAGAN-GENII is used for quantitative scenario analysis. Detailed data used in this module are come from experimental data of Korean territory and default data given within this module. Is case of blank data for code execution, it is estimated through reasonable engineering sense

Magnetic force microscopy : Quantitative issues in biomaterials

NARCIS (Netherlands)

Passeri, D.; Dong, C.; Reggente, M.; Angeloni, L.; Barteri, M.; Scaramuzzo, F.A.; De Angelis, F.; Marinelli, F.; Antonelli, F.; Rinaldi, F.; Marianecci, C.; Carafa, M.; Sorbo, A.; Sordi, D.; Arends, I.W.C.E.; Rossi, M.

2014-01-01

Magnetic force microscopy (MFM) is an atomic force microscopy (AFM) based technique in which an AFM tip with a magnetic coating is used to probe local magnetic fields with the typical AFM spatial resolution, thus allowing one to acquire images reflecting the local magnetic properties of the samples

Microchromatography of hemoglobins. VIII. A general qualitative and quantitative method in plastic drinking straws and the quantitative analysis of Hb-F.

Science.gov (United States)

Schroeder, W A; Pace, L A

1978-03-01

The microchromatographic procedure for the quantitative analysis of the hemoglobin components in a hemolysate uses columns of DEAE-cellulose in a plastic drinking straw with a glycine-KCN-NaCl developer. Not only may the method be used for the quantitative analysis of Hb-F but also for the analysis of the varied components in mixtures of hemoglobins.

Direct visualization of glutamate transporter elevator mechanism by high-speed AFM.

Science.gov (United States)

Ruan, Yi; Miyagi, Atsushi; Wang, Xiaoyu; Chami, Mohamed; Boudker, Olga; Scheuring, Simon

2017-02-14

Glutamate transporters are essential for recovery of the neurotransmitter glutamate from the synaptic cleft. Crystal structures in the outward- and inward-facing conformations of a glutamate transporter homolog from archaebacterium Pyrococcus horikoshii , sodium/aspartate symporter Glt Ph , suggested the molecular basis of the transporter cycle. However, dynamic studies of the transport mechanism have been sparse and indirect. Here we present high-speed atomic force microscopy (HS-AFM) observations of membrane-reconstituted Glt Ph at work. HS-AFM movies provide unprecedented real-space and real-time visualization of the transport dynamics. Our results show transport mediated by large amplitude 1.85-nm "elevator" movements of the transport domains consistent with previous crystallographic and spectroscopic studies. Elevator dynamics occur in the absence and presence of sodium ions and aspartate, but stall in sodium alone, providing a direct visualization of the ion and substrate symport mechanism. We show unambiguously that individual protomers within the trimeric transporter function fully independently.

Quantitative genetic analysis of total glucosinolate, oil and protein ...

African Journals Online (AJOL)

Quantitative genetic analysis of total glucosinolate, oil and protein contents in Ethiopian mustard ( Brassica carinata A. Braun) ... Seeds were analyzed using HPLC (glucosinolates), NMR (oil) and NIRS (protein). Analyses of variance, Hayman's method of diallel analysis and a mixed linear model of genetic analysis were ...

Design of a micro-cartridge system for the robotic assembly of exchangeable AFM-probe tips

DEFF Research Database (Denmark)

Bartenwerfer, Malte; Eichhorn, Volkmar; Fatikow, Sergej

2013-01-01

demand an even higher lateral resolution of the measurements. The atomic force microscope (AFM) is a common tool for this characterization and a standard instrument for all kinds of research and development disciplines. However, the characterization of three dimensional high-aspect ratio and sidewall...... structures remains a hardly accomplishable task. Novel exchangeable and customizable scanning probe tips, so-called NanoBits, can be attached to standard AFM cantilevers offering unprecedented freedom in adapting the shape and size of the tips to the surface topology of the specific application. The ultimate...

Quantiprot - a Python package for quantitative analysis of protein sequences.

Science.gov (United States)

Konopka, Bogumił M; Marciniak, Marta; Dyrka, Witold

2017-07-17

The field of protein sequence analysis is dominated by tools rooted in substitution matrices and alignments. A complementary approach is provided by methods of quantitative characterization. A major advantage of the approach is that quantitative properties defines a multidimensional solution space, where sequences can be related to each other and differences can be meaningfully interpreted. Quantiprot is a software package in Python, which provides a simple and consistent interface to multiple methods for quantitative characterization of protein sequences. The package can be used to calculate dozens of characteristics directly from sequences or using physico-chemical properties of amino acids. Besides basic measures, Quantiprot performs quantitative analysis of recurrence and determinism in the sequence, calculates distribution of n-grams and computes the Zipf's law coefficient. We propose three main fields of application of the Quantiprot package. First, quantitative characteristics can be used in alignment-free similarity searches, and in clustering of large and/or divergent sequence sets. Second, a feature space defined by quantitative properties can be used in comparative studies of protein families and organisms. Third, the feature space can be used for evaluating generative models, where large number of sequences generated by the model can be compared to actually observed sequences.

A Novel Dog-Bone Oscillating AFM Probe with Thermal Actuation and Piezoresistive Detection †

Science.gov (United States)

Xiong, Zhuang; Mairiaux, Estelle; Walter, Benjamin; Faucher, Marc; Buchaillot, Lionel; Legrand, Bernard

2014-01-01

In order to effectively increase the resonance frequency and the quality factor of atomic force microscope (AFM) probes, a novel oscillating probe based on a dog-bone shaped MEMS resonator was conceived, designed, fabricated and evaluated. The novel probe with 400 μm in length, 100 μm in width and 5 μm in thickness was enabled to feature MHz resonance frequencies with integrated thermal actuation and piezoresistive detection. Standard silicon micromachining was employed. Both electrical and optical measurements were carried out in air. The resonance frequency and the quality factor of the novel probe were measured to be 5.4 MHz and 4000 respectively, which are much higher than those (about several hundreds of kHz) of commonly used cantilever probes. The probe was mounted onto a commercial AFM set-up through a dedicated probe-holder and circuit board. Topographic images of patterned resist samples were obtained. It is expected that the resonance frequency and the measurement bandwidth of such probes will be further increased by a proper downscaling, thus leading to a significant increase in the scanning speed capability of AFM instruments. PMID:25365463

A concept for automated nanoscale atomic force microscope (AFM) measurements using a priori knowledge

International Nuclear Information System (INIS)

Recknagel, C; Rothe, H

2009-01-01

The nanometer coordinate measuring machine (NCMM) is developed for comparatively fast large area scans with high resolution. The system combines a metrological atomic force microscope (AFM) with a precise positioning system. The sample is moved under the probe system via the positioning system achieving a scan range of 25 × 25 × 5 mm 3 with a resolution of 0.1 nm. A concept for AFM measurements using a priori knowledge is implemented. The a priori knowledge is generated through measurements with a white light interferometer and the use of CAD data. Dimensional markup language is used as a transfer and target format for a priori knowledge and measurement data. Using the a priori knowledge and template matching algorithms combined with the optical microscope of the NCMM, the region of interest can automatically be identified. In the next step the automatic measurement of the part coordinate system and the measurement elements with the AFM sensor of the NCMM is done. The automatic measurement involves intelligent measurement strategies, which are adapted to specific geometries of the measurement feature to reduce measurement time and drift effects

The usefulness of 3D quantitative analysis with using MRI for measuring osteonecrosis of the femoral head

International Nuclear Information System (INIS)

Hwang, Ji Young; Lee, Sun Wha; Park, Youn Soo

2006-01-01

We wanted to evaluate the usefulness of MRI 3D quantitative analysis for measuring osteonecrosis of the femoral head in comparison with MRI 2D quantitative analysis and quantitative analysis of the specimen. For 3 months at our hospital, 14 femoral head specimens with osteonecrosis were obtained after total hip arthroplasty. The patients preoperative MRIs were retrospectively reviewed for quantitative analysis of the size of the necrosis. Each necrotic fraction of the femoral head was measured by 2D quantitative analysis with using mid-coronal and mid-sagittal MRIs, and by 3D quantitative analysis with using serial continuous coronal MRIs and 3D reconstruction software. The necrotic fraction of the specimen was physically measured by the fluid displacement method. The necrotic fraction according to MRI 2D or 3D quantitative analysis was compared with that of the specimen by using Spearman's correlation test. On the correlative analysis, the necrotic fraction by MRI 2D quantitative analysis and quantitative analysis of the specimen showed moderate correlation (r = 0.657); on the other hand, the necrotic fraction by MRI 3D quantitative analysis and quantitative analysis of the specimen demonstrated a strong correlation (r = 0.952) (ρ < 0.05). MRI 3D quantitative analysis was more accurate than 2D quantitative analysis using MRI for measuring osteonecrosis of the femoral head. Therefore, it may be useful for predicting the clinical outcome and deciding the proper treatment option

What Really Happens in Quantitative Group Research? Results of a Content Analysis of Recent Quantitative Research in "JSGW"

Science.gov (United States)

Boyle, Lauren H.; Whittaker, Tiffany A.; Eyal, Maytal; McCarthy, Christopher J.

2017-01-01

The authors conducted a content analysis on quantitative studies published in "The Journal for Specialists in Group Work" ("JSGW") between 2012 and 2015. This brief report provides a general overview of the current practices of quantitative group research in counseling. The following study characteristics are reported and…

Quantitative proteomic analysis of post-translational modifications of human histones

DEFF Research Database (Denmark)

Beck, Hans Christian; Nielsen, Eva C; Matthiesen, Rune

2006-01-01

, and H4 in a site-specific and dose-dependent manner. This unbiased analysis revealed that a relative increase in acetylated peptide from the histone variants H2A, H2B, and H4 was accompanied by a relative decrease of dimethylated Lys(57) from histone H2B. The dose-response results obtained...... by quantitative proteomics of histones from HDACi-treated cells were consistent with Western blot analysis of histone acetylation, cytotoxicity, and dose-dependent expression profiles of p21 and cyclin A2. This demonstrates that mass spectrometry-based quantitative proteomic analysis of post-translational...

Characterization and analysis of weld lines on micro-injection moulded parts using atomic force microscopy (AFM)

DEFF Research Database (Denmark)

Tosello, Guido; Gava, Alberto; Hansen, Hans Nørgaard

2009-01-01

In recent years plastic moulding techniques, such as injection moulding, have been developed to fulfil the needs of micro-components fabrication. Micro-injection moulding (SLIM) is the process which enables the mass production of polymer micro-systems such as micro-mechanical parts, micro...... the two original flows will generate and a weld line is formed on the surface of the micro-moulded part. This phenomenon has to be avoided or at least reduced, since in the weld line area the mechanical properties are poorer than in the bulk part, creating strength problems on the final part. Although...... injection moulding parameters on the weld lines' dimensions is presented, using an atomic force microscope (AFM). Depth and width of weld lines were chosen as parameters to be optimized....

Data from quantitative label free proteomics analysis of rat spleen.

Science.gov (United States)

Dudekula, Khadar; Le Bihan, Thierry

2016-09-01

The dataset presented in this work has been obtained using a label-free quantitative proteomic analysis of rat spleen. A robust method for extraction of proteins from rat spleen tissue and LC-MS-MS analysis was developed using a urea and SDS-based buffer. Different fractionation methods were compared. A total of 3484 different proteins were identified from the pool of all experiments run in this study (a total of 2460 proteins with at least two peptides). A total of 1822 proteins were identified from nine non-fractionated pulse gels, 2288 proteins and 2864 proteins were identified by SDS-PAGE fractionation into three and five fractions respectively. The proteomics data are deposited in ProteomeXchange Consortium via PRIDE PXD003520, Progenesis and Maxquant output are presented in the supported information. The generated list of proteins under different regimes of fractionation allow assessing the nature of the identified proteins; variability in the quantitative analysis associated with the different sampling strategy and allow defining a proper number of replicates for future quantitative analysis.

Quantitative analysis of some brands of chloroquine tablets ...

African Journals Online (AJOL)

Quantitative analysis of some brands of chloroquine tablets marketed in Maiduguri using spectrophotometric ... and compared with that of the standard, wavelength of maximum absorbance at 331nm for chloroquine. ... HOW TO USE AJOL.

Accurate quantitative XRD phase analysis of cement clinkers

International Nuclear Information System (INIS)

Kern, A.

2002-01-01

Full text: Knowledge about the absolute phase abundance in cement clinkers is a requirement for both, research and quality control. Traditionally, quantitative analysis of cement clinkers has been carried out by theoretical normative calculation from chemical analysis using the so-called Bogue method or by optical microscopy. Therefore chemical analysis, mostly performed by X-ray fluorescence (XRF), forms the basis of cement plan control by providing information for proportioning raw materials, adjusting kiln and burning conditions, as well as cement mill feed proportioning. In addition, XRF is of highest importance with respect to the environmentally relevant control of waste recovery raw materials and alternative fuels, as well as filters, plants and sewage. However, the performance of clinkers and cements is governed by the mineralogy and not the elemental composition, and the deficiencies and inherent errors of Bogue as well as microscopic point counting are well known. With XRD and Rietveld analysis a full quantitative analysis of cement clinkers can be performed providing detailed mineralogical information about the product. Until recently several disadvantages prevented the frequent application of the Rietveld method in the cement industry. As the measurement of a full pattern is required, extended measurement times made an integration of this method into existing automation environments difficult. In addition, several drawbacks of existing Rietveld software such as complexity, low performance and severe numerical instability were prohibitive for automated use. The latest developments of on-line instrumentation, as well as dedicated Rietveld software for quantitative phase analysis (TOPAS), now make a decisive breakthrough possible. TOPAS not only allows the analysis of extremely complex phase mixtures in the shortest time possible, but also a fully automated online phase analysis for production control and quality management, free of any human interaction

SNOM and AFM microscopy techniques to study the effect of non-ionizing radiation on the morphological and biochemical properties of human keratinocytes cell line (HaCaT).

Science.gov (United States)

Rieti, S; Manni, V; Lisi, A; Giuliani, L; Sacco, D; D'Emilia, E; Cricenti, A; Generosi, R; Luce, M; Grimaldi, S

2004-01-01

In this study we have employed atomic force microscopy (AFM) and scanning near-field optical microscopy (SNOM) techniques to study the effect of the interaction between human keratinocytes (HaCaT) and electromagnetic fields at low frequency. HaCaT cells were exposed to a sinusoidal magnetic field at a density of 50 Hz, 1 mT. AFM analysis revealed modification in shape and morphology in exposed cells with an increase in the areas of adhesion between cells. This latter finding was confirmed by SNOM indirect immunofluorescence analysis performed with a fluorescent antibody against the adhesion marker beta4 integrin, which revealed an increase of beta4 integrin segregation in the cell membrane of 50-Hz exposed cells, suggesting that a higher percentage of these cells shows a modified pattern of this adhesion marker.

Global scaling for semi-quantitative analysis in FP-CIT SPECT.

Science.gov (United States)

Kupitz, D; Apostolova, I; Lange, C; Ulrich, G; Amthauer, H; Brenner, W; Buchert, R

2014-01-01

Semi-quantitative characterization of dopamine transporter availability from single photon emission computed tomography (SPECT) with 123I-ioflupane (FP-CIT) is based on uptake ratios relative to a reference region. The aim of this study was to evaluate the whole brain as reference region for semi-quantitative analysis of FP-CIT SPECT. The rationale was that this might reduce statistical noise associated with the estimation of non-displaceable FP-CIT uptake. 150 FP-CIT SPECTs were categorized as neurodegenerative or non-neurodegenerative by an expert. Semi-quantitative analysis of specific binding ratios (SBR) was performed with a custom-made tool based on the Statistical Parametric Mapping software package using predefined regions of interest (ROIs) in the anatomical space of the Montreal Neurological Institute. The following reference regions were compared: predefined ROIs for frontal and occipital lobe and whole brain (without striata, thalamus and brainstem). Tracer uptake in the reference region was characterized by the mean, median or 75th percentile of its voxel intensities. The area (AUC) under the receiver operating characteristic curve was used as performance measure. The highest AUC of 0.973 was achieved by the SBR of the putamen with the 75th percentile in the whole brain as reference. The lowest AUC for the putamen SBR of 0.937 was obtained with the mean in the frontal lobe as reference. We recommend the 75th percentile in the whole brain as reference for semi-quantitative analysis in FP-CIT SPECT. This combination provided the best agreement of the semi-quantitative analysis with visual evaluation of the SPECT images by an expert and, therefore, is appropriate to support less experienced physicians.

Quantitative possibility analysis. Present status in ESCA

International Nuclear Information System (INIS)

Brion, D.

1981-01-01

A short review of the recent developments in quantification of X-ray photoelectron spectroscopy or ESCA is presented. The basic equations are reminded. Each involved parameter (photoionisation, inelastic mean free paths, 'response function' of the instruments, intensity measurement) is separately discussed in relation with the accuracy and the precision of the method. Other topics are considered such as roughness, surface contamination, matrix effect and inhomogeneous composition. Some aspects of the quantitative ESCA analysis and AES analysis are compared [fr

Uncertainties in elemental quantitative analysis by PIXE

International Nuclear Information System (INIS)

Montenegro, E.C.; Baptista, G.B.; Paschoa, A.S.; Barros Leite, C.V.

1979-01-01

The effects of the degree of non-uniformity of the particle beam, matrix composition and matrix thickness in a quantitative elemental analysis by particle induced X-ray emission (PIXE) are discussed and a criterion to evaluate the resulting degree of uncertainty in the mass determination by this method is established. (Auth.)

Quantitative analysis of γ-oryzanol content in cold pressed rice bran oil by TLC-image analysis method

OpenAIRE

Sakunpak, Apirak; Suksaeree, Jirapornchai; Monton, Chaowalit; Pathompak, Pathamaporn; Kraisintu, Krisana

2014-01-01

Objective: To develop and validate an image analysis method for quantitative analysis of γ-oryzanol in cold pressed rice bran oil. Methods: TLC-densitometric and TLC-image analysis methods were developed, validated, and used for quantitative analysis of γ-oryzanol in cold pressed rice bran oil. The results obtained by these two different quantification methods were compared by paired t-test. Results: Both assays provided good linearity, accuracy, reproducibility and selectivity for dete...

Evaluation of breast lesions by contrast enhanced ultrasound: Qualitative and quantitative analysis

International Nuclear Information System (INIS)

Wan Caifeng; Du Jing; Fang Hua; Li Fenghua; Wang Lin

2012-01-01

Objective: To evaluate and compare the diagnostic performance of qualitative, quantitative and combined analysis for characterization of breast lesions in contrast enhanced ultrasound (CEUS), with histological results used as the reference standard. Methods: Ninety-one patients with 91 breast lesions BI-RADS 3–5 at US or mammography underwent CEUS. All lesions underwent qualitative and quantitative enhancement evaluation. Receiver operating characteristic (ROC) curve analysis was performed to evaluate the diagnostic performance of different analytical method for discrimination between benign and malignant breast lesions. Results: Histopathologic analysis of the 91 lesions revealed 44 benign and 47 malignant. For qualitative analysis, benign and malignant lesions differ significantly in enhancement patterns (p z1 ), 0.768 (A z2 ) and 0.926(A z3 ) respectively. The values of A z1 and A z3 were significantly higher than that for A z2 (p = 0.024 and p = 0.008, respectively). But there was no significant difference between the values of A z1 and A z3 (p = 0.625). Conclusions: The diagnostic performance of qualitative and combined analysis was significantly higher than that for quantitative analysis. Although quantitative analysis has the potential to differentiate benign from malignant lesions, it has not yet improved the final diagnostic accuracy.

AFM surface imaging of AISI D2 tool steel machined by the EDM process

International Nuclear Information System (INIS)

Guu, Y.H.

2005-01-01

The surface morphology, surface roughness and micro-crack of AISI D2 tool steel machined by the electrical discharge machining (EDM) process were analyzed by means of the atomic force microscopy (AFM) technique. Experimental results indicate that the surface texture after EDM is determined by the discharge energy during processing. An excellent machined finish can be obtained by setting the machine parameters at a low pulse energy. The surface roughness and the depth of the micro-cracks were proportional to the power input. Furthermore, the AFM application yielded information about the depth of the micro-cracks is particularly important in the post treatment of AISI D2 tool steel machined by EDM

AFM surface imaging of AISI D2 tool steel machined by the EDM process

Science.gov (United States)

Guu, Y. H.

2005-04-01

The surface morphology, surface roughness and micro-crack of AISI D2 tool steel machined by the electrical discharge machining (EDM) process were analyzed by means of the atomic force microscopy (AFM) technique. Experimental results indicate that the surface texture after EDM is determined by the discharge energy during processing. An excellent machined finish can be obtained by setting the machine parameters at a low pulse energy. The surface roughness and the depth of the micro-cracks were proportional to the power input. Furthermore, the AFM application yielded information about the depth of the micro-cracks is particularly important in the post treatment of AISI D2 tool steel machined by EDM.

New Approach to Quantitative Analysis by Laser-induced Breakdown Spectroscopy

International Nuclear Information System (INIS)

Lee, D. H.; Kim, T. H.; Yun, J. I.; Jung, E. C.

2009-01-01

Laser-induced breakdown spectroscopy (LIBS) has been studied as the technique of choice in some particular situations like screening, in situ measurement, process monitoring, hostile environments, etc. Especially, LIBS can fulfill the qualitative and quantitative analysis for radioactive high level waste (HLW) glass in restricted experimental conditions. Several ways have been suggested to get quantitative information from LIBS. The one approach is to use the absolute intensities of each element. The other approach is to use the elemental emission intensities relative to the intensity of the internal standard element whose concentration is known already in the specimen. But these methods are not applicable to unknown samples. In the present work, we introduce new approach to LIBS quantitative analysis by using H α (656.28 nm) emission line as external standard

Crystallinity and compositional changes in carbonated apatites: Evidence from 31P solid-state NMR, Raman, and AFM analysis

Science.gov (United States)

McElderry, John-David P.; Zhu, Peizhi; Mroue, Kamal H.; Xu, Jiadi; Pavan, Barbara; Fang, Ming; Zhao, Guisheng; McNerny, Erin; Kohn, David H.; Franceschi, Renny T.; Holl, Mark M. Banaszak; Tecklenburg, Mary M. J.; Ramamoorthy, Ayyalusamy; Morris, Michael D.

2013-10-01

Solid-state (magic-angle spinning) NMR spectroscopy is a useful tool for obtaining structural information on bone organic and mineral components and synthetic model minerals at the atomic-level. Raman and 31P NMR spectral parameters were investigated in a series of synthetic B-type carbonated apatites (CAps). Inverse 31P NMR linewidth and inverse Raman PO43-ν1 bandwidth were both correlated with powder XRD c-axis crystallinity over the 0.3-10.3 wt% CO32- range investigated. Comparison with bone powder crystallinities showed agreement with values predicted by NMR and Raman calibration curves. Carbonate content was divided into two domains by the 31P NMR chemical shift frequency and the Raman phosphate ν1 band position. These parameters remain stable except for an abrupt transition at 6.5 wt% carbonate, a composition which corresponds to an average of one carbonate per unit cell. This near-binary distribution of spectroscopic properties was also found in AFM-measured particle sizes and Ca/P molar ratios by elemental analysis. We propose that this transition differentiates between two charge-balancing ion-loss mechanisms as measured by Ca/P ratios. These results define a criterion for spectroscopic characterization of B-type carbonate substitution in apatitic minerals.

Protein analysis by 31p NMR spectroscopy in ionic liquid: quantitative determination of enzymatically created cross-links.

Science.gov (United States)

Monogioudi, Evanthia; Permi, Perttu; Filpponen, Ilari; Lienemann, Michael; Li, Bin; Argyropoulos, Dimitris; Buchert, Johanna; Mattinen, Maija-Liisa

2011-02-23

Cross-linking of β-casein by Trichoderma reesei tyrosinase (TrTyr) and Streptoverticillium mobaraense transglutaminase (Tgase) was analyzed by (31)P nuclear magnetic resonance (NMR) spectroscopy in ionic liquid (IL). According to (31)P NMR, 91% of the tyrosine side chains were cross-linked by TrTyr at high dosages. When Tgase was used, no changes were observed because a different cross-linking mechanism was operational. However, this verified the success of the phosphitylation of phenolics within the protein matrix in the IL. Atomic force microscopy (AFM) in solid state showed that disk-shaped nanoparticles were formed in the reactions with average diameters of 80 and 20 nm for TrTyr and Tgase, respectively. These data further advance the current understanding of the action of tyrosinases on proteins on molecular and chemical bond levels. Quantitative (31)P NMR in IL was shown to be a simple and efficient method for the study of protein modification.

Nanospot soldering polystyrene nanoparticles with an optical fiber probe laser irradiating a metallic AFM probe based on the near-field enhancement effect.

Science.gov (United States)

Cui, Jianlei; Yang, Lijun; Wang, Yang; Mei, Xuesong; Wang, Wenjun; Hou, Chaojian

2015-02-04

With the development of nanoscience and nanotechnology for the bottom-up nanofabrication of nanostructures formed from polystyrene nanoparticles, joining technology is an essential step in the manufacturing and assembly of nanodevices and nanostructures in order to provide mechanical integration and connection. To study the nanospot welding of polystyrene nanoparticles, we propose a new nanospot-soldering method using the near-field enhancement effect of a metallic atomic force microscope (AFM) probe tip that is irradiated by an optical fiber probe laser. On the basis of our theoretical analysis of the near-field enhancement effect, we set up an experimental system for nanospot soldering; this approach is carried out by using an optical fiber probe laser to irradiate the AFM probe tip to sinter the nanoparticles, providing a promising technical approach for the application of nanosoldering in nanoscience and nanotechnology.

BOREAS AFM-6 Boundary Layer Height Data

Science.gov (United States)

Wilczak, James; Hall, Forrest G. (Editor); Newcomer, Jeffrey A. (Editor); Smith, David E. (Technical Monitor)

2000-01-01

The Boreal Ecosystem-Atmosphere Study (BOREAS) Airborne Fluxes and Meteorology (AFM)-6 team from National Oceanic and Atmospheric Adminsitration/Environment Technology Laboratory (NOAA/ETL) operated a 915-MHz wind/Radio Acoustic Sounding System (RASS) profiler system in the Southern Study Area (SSA) near the Old Jack Pine (OJP) site. This data set provides boundary layer height information over the site. The data were collected from 21 May 1994 to 20 Sep 1994 and are stored in tabular ASCII files. The boundary layer height data are available from the Earth Observing System Data and Information System (EOSDIS) Oak Ridge National Laboratory (ORNL) Distributed Active Archive Center (DAAC). The data files are available on a CD-ROM (see document number 20010000884).

A low-cost AFM setup with an interferometer for undergraduates and secondary-school students

International Nuclear Information System (INIS)

Bergmann, Antje; Feigl, Daniela; Kuhn, David; Schaupp, Manuel; Quast, Günter; Busch, Kurt; Eichner, Ludwig; Schumacher, Jens

2013-01-01

Atomic force microscopy (AFM) is an important tool in nanotechnology. This method makes it possible to observe nanoscopic surfaces beyond the resolution of light microscopy. In order to provide undergraduate and secondary-school students with insights into this world, we have developed a very robust low-cost AFM setup with a Fabry–Perot interferometer as a detecting device. This setup is designed to be operated almost completely manually and its simplicity gives access to a profound understanding of the working principle. Our AFM is operated in a constant height mode, i.e. the topography of the sample surface is represented directly by the deflection of the cantilever. Thus, the measuring procedure can be understood even by secondary-school students; furthermore, it is the method with the lowest cost, totalling not more than 10–15 k Euros. Nevertheless, we are able to examine a large variety of sample topographies such as CD and DVD surfaces, IC structures, blood cells, butterfly wings or moth eyes. Furthermore, force–distance curves can be recorded and the tensile moduli of some materials can be evaluated. We present our setup in detail and describe its working principles. In addition, we show various experiments which have already been performed by students. (paper)

Surface study of irradiated sapphires from Phrae Province, Thailand using AFM

Science.gov (United States)

Monarumit, N.; Jivanantaka, P.; Mogmued, J.; Lhuaamporn, T.; Satitkune, S.

2017-09-01

The irradiation is one of the gemstone enhancements for improving the gem quality. Typically, there are many varieties of irradiated gemstones in the gem market such as diamond, topaz, and sapphire. However, it is hard to identify the gemstones before and after irradiation. The aim of this study is to analyze the surface morphology for classifying the pristine and irradiated sapphires using atomic force microscope (AFM). In this study, the sapphire samples were collected from Phrae Province, Thailand. The samples were irradiated by high energy electron beam for a dose of ionizing radiation at 40,000 kGy. As the results, the surface morphology of pristine sapphires shows regular atomic arrangement, whereas, the surface morphology of irradiated sapphires shows the nano-channel observed by the 2D and 3D AFM images. The atomic step height and root mean square roughness have changed after irradiation due to the micro-structural defect on the sapphire surface. Therefore, this study is a frontier application for sapphire identification before and after irradiation.

Automatic determination of the size of elliptical nanoparticles from AFM images

International Nuclear Information System (INIS)

Sedlář, Jiří; Zitová, Barbara; Kopeček, Jaromír; Flusser, Jan; Todorciuc, Tatiana; Kratochvílová, Irena

2013-01-01

The objective of this work was to develop an accurate method for automatic determination of the size of elliptical nanoparticles from atomic force microscopy (AFM) images that would yield results consistent with results of manual measurements by experts. The proposed method was applied on phenylpyridyldiketopyrrolopyrrole (PPDP), a granular organic material with a wide scale of application and highly sensitive particle-size properties. A PPDP layer consists of similarly sized elliptical particles (c. 100 nm × 50 nm) and its properties can be estimated from the average length and width of the particles. The developed method is based on segmentation of salient particles by the watershed transform and approximation of their shapes by ellipses computed by image moments; it estimates the lengths and widths of the particles by the major and minor axes, respectively, of the corresponding ellipses. Its results proved to be consistent with results of manual measurements by a trained expert. The comparison showed that the developed method could be used in practice for precise automatic measurement of PPDP particles in AFM images

Multicomponent quantitative spectroscopic analysis without reference substances based on ICA modelling.

Science.gov (United States)

Monakhova, Yulia B; Mushtakova, Svetlana P

2017-05-01

A fast and reliable spectroscopic method for multicomponent quantitative analysis of targeted compounds with overlapping signals in complex mixtures has been established. The innovative analytical approach is based on the preliminary chemometric extraction of qualitative and quantitative information from UV-vis and IR spectral profiles of a calibration system using independent component analysis (ICA). Using this quantitative model and ICA resolution results of spectral profiling of "unknown" model mixtures, the absolute analyte concentrations in multicomponent mixtures and authentic samples were then calculated without reference solutions. Good recoveries generally between 95% and 105% were obtained. The method can be applied to any spectroscopic data that obey the Beer-Lambert-Bouguer law. The proposed method was tested on analysis of vitamins and caffeine in energy drinks and aromatic hydrocarbons in motor fuel with 10% error. The results demonstrated that the proposed method is a promising tool for rapid simultaneous multicomponent analysis in the case of spectral overlap and the absence/inaccessibility of reference materials.

ImatraNMR: Novel software for batch integration and analysis of quantitative NMR spectra

Science.gov (United States)

Mäkelä, A. V.; Heikkilä, O.; Kilpeläinen, I.; Heikkinen, S.

2011-08-01

Quantitative NMR spectroscopy is a useful and important tool for analysis of various mixtures. Recently, in addition of traditional quantitative 1D 1H and 13C NMR methods, a variety of pulse sequences aimed for quantitative or semiquantitative analysis have been developed. To obtain actual usable results from quantitative spectra, they must be processed and analyzed with suitable software. Currently, there are many processing packages available from spectrometer manufacturers and third party developers, and most of them are capable of analyzing and integration of quantitative spectra. However, they are mainly aimed for processing single or few spectra, and are slow and difficult to use when large numbers of spectra and signals are being analyzed, even when using pre-saved integration areas or custom scripting features. In this article, we present a novel software, ImatraNMR, designed for batch analysis of quantitative spectra. In addition to capability of analyzing large number of spectra, it provides results in text and CSV formats, allowing further data-analysis using spreadsheet programs or general analysis programs, such as Matlab. The software is written with Java, and thus it should run in any platform capable of providing Java Runtime Environment version 1.6 or newer, however, currently it has only been tested with Windows and Linux (Ubuntu 10.04). The software is free for non-commercial use, and is provided with source code upon request.

In situ QCM and TM-AFM investigations of the early stages of degradation of silver and copper surfaces

International Nuclear Information System (INIS)

Kleber, Ch.; Hilfrich, U.; Schreiner, M.

2007-01-01

The early stages of atmospheric corrosion of pure copper and pure silver specimens were investigated performing in situ tapping mode atomic force microscopy (TM-AFM), in situ quartz crystal microbalance (QCM) and X-ray photoelectron spectroscopy (XPS). The information obtained by TM-AFM is the change of the topography of the sample surfaces with emphasis on the shape and lateral distribution of the corrosion products grown within the first hours of weathering. The simultaneously performed in situ QCM measurements are indicating the mass changes due to possibly occurring corrosive processes on the surface during weathering and are therefore a valuable tool for the determination of corrosion rates. Investigations were carried out in synthetic air at different levels of relative humidity (RH) with and without addition of 250 ppb SO 2 as acidifying agent. On a polished copper surface the growth of corrosion products could be observed by TM-AFM analysis at 60% RH without any addition of acidifying gases [M. Wadsak, M. Schreiner, T. Aastrup, C. Leygraf, Surf. Sci. 454-456 (2000) 246-250]. On a weathered copper surface the addition of SO 2 to the moist air stream leads to the formation of additional features as already described in the literature [M. Wadsak, M. Schreiner, T. Aastrup, C. Leygraf, Surf. Sci. 454-456 (2000) 246-250; Ch. Kleber, J. Weissenrieder, M. Schreiner, C. Leygraf, Appl. Surf. Sci. 193 (2002) 245-253]. Exposing a silver specimen to humidity leads to the degradation of the surface structure as well as to a formation of corrosion products, which could be detected by in situ QCM measurements. After addition of 250 ppb SO 2 to the moist gas stream an increase of the formed feature's volume on the silver surface could be observed by TM-AFM measurements. The results obtained additionally from the in situ QCM measurements confirm the influence of SO 2 due to a further increase of the mass of the formed corrosion layer (and therefore an increase of the

Observation of Shapiro-steps in AFM-plought micron-size YBCO planar construction

CSIR Research Space (South Africa)

Elkaseh, AAO

2009-01-01

Full Text Available Using an Atomic Force Microscope (AFM), micron size planar constriction type junctions was successfully ploughed on YBa2Cu3O7-x thin films. The 100 nanometer (nm) thin films are deposited on MgO substrates by an Inverted Cylindrical Magnetron (ICM...

Laser-damage susceptibility of nodular defects in dielectric mirror coatings: AFM measurements and electric-field modeling

International Nuclear Information System (INIS)

Kozlowski, M.R.; DeFord, J.F.; Staggs, M.C.

1993-01-01

Atomic force microscopy (AFM) and electromagnetic field modeling were used to study the influence of nodular coating defects on laser-induced damage of multilayer dielectric coatings. In studies of HfO 2 /SiO 2 mirrors with 1.06 μm illumination, AFM results showed that nodular defects with high dome heights (>0.6 μm) were most susceptible to laser damage. Crater defects, formed by nodules ejected from the coating prior to illumination, were not damaged when illuminated over the same range of fluences. A finite-difference time-domain electromagnetic modeling code was used to study the influence of 3-D nodule defects on the E-field distribution within the interference coating. The modeling results show that Enfield enhancements as large as a factor of 4 can be present at the defects. Crater defects, however, result in minimal enhancement of the E-fields within the coating. These modeling results are consistent with the AFM experimental data, indicating that E-field enhancement is a contributing mechanism in defect-dominated laser damage of optical coatings

Quantitative subsurface analysis using frequency modulated thermal wave imaging

Science.gov (United States)

Subhani, S. K.; Suresh, B.; Ghali, V. S.

2018-01-01

Quantitative depth analysis of the anomaly with an enhanced depth resolution is a challenging task towards the estimation of depth of the subsurface anomaly using thermography. Frequency modulated thermal wave imaging introduced earlier provides a complete depth scanning of the object by stimulating it with a suitable band of frequencies and further analyzing the subsequent thermal response using a suitable post processing approach to resolve subsurface details. But conventional Fourier transform based methods used for post processing unscramble the frequencies with a limited frequency resolution and contribute for a finite depth resolution. Spectral zooming provided by chirp z transform facilitates enhanced frequency resolution which can further improves the depth resolution to axially explore finest subsurface features. Quantitative depth analysis with this augmented depth resolution is proposed to provide a closest estimate to the actual depth of subsurface anomaly. This manuscript experimentally validates this enhanced depth resolution using non stationary thermal wave imaging and offers an ever first and unique solution for quantitative depth estimation in frequency modulated thermal wave imaging.

Determination of Morphological Parameters of Supported Gold Nanoparticles: Comparison of AFM Combined with Optical Spectroscopy and Theoretical Modeling versus TEM

Directory of Open Access Journals (Sweden)

Frank Hubenthal

2012-07-01

Full Text Available The morphology of small gold particles prepared by Volmer–Weber growth on sapphire substrates have been investigated by two different characterization techniques. First, by non-extensive atomic force microscopy (AFM in combination with optical spectroscopy and modeling of the optical properties using a theoretical model, recently developed in our group. Second, by extensive transmission electron microscopy (TEM. Comparing the results obtained with both techniques demonstrate that for small gold nanoparticles within the quasistatic limit, the morphological properties can be precisely determined by an appropriate theoretical modeling of the optical properties in combination with simple AFM measurements. The apparent mean axial ratio of the nanoparticles, i.e., the axial ratio that corresponds to the center frequency of the ensemble plasmon resonance, is obtained easily from the extinction spectrum. The mean size is determined by the nanoparticle number density and the amount of deposited material, measured by AFM and a quartz micro balance, respectively. To extract the most probable axial ratio of the nanoparticle ensemble, i.e., the axial ratio that corresponds to the most probable nanoparticle size in the ensemble, we apply the new theoretical model, which allows to extract the functional dependence of the nanoparticle shape on its size. The morphological parameters obtained with this procedure will be afterwards compared to extensive TEM measurements. The results obtained with both techniques yield excellent agreement. For example, the lateral dimensions of the nanoparticles after deposition of 15.2 × 1015 atoms/cm2 of gold has been compared. While a mean lateral diameter of (13 ± 2 nm has been extracted from AFM, optical spectroscopy and modeling, a value of (12 ± 2 nm is derived from TEM. The consistency of the results demonstrate the precision of our new model. Moreover, since our theoretical model allows to extract the functional

Quantitative analysis by nuclear magnetic resonance spectroscopy

Energy Technology Data Exchange (ETDEWEB)

Wainai, T; Mashimo, K [Nihon Univ., Tokyo. Coll. of Science and Engineering

1976-04-01

Recent papers on the practical quantitative analysis by nuclear magnetic resonance spectroscopy (NMR) are reviewed. Specifically, the determination of moisture in liquid N/sub 2/O/sub 4/ as an oxidizing agent for rocket propulsion, the analysis of hydroperoxides, the quantitative analysis using a shift reagent, the analysis of aromatic sulfonates, and the determination of acids and bases are reviewed. Attention is paid to the accuracy. The sweeping velocity and RF level in addition to the other factors must be on the optimal condition to eliminate the errors, particularly when computation is made with a machine. Higher sweeping velocity is preferable in view of S/N ratio, but it may be limited to 30 Hz/s. The relative error in the measurement of area is generally 1%, but when those of dilute concentration and integrated, the error will become smaller by one digit. If impurities are treated carefully, the water content on N/sub 2/O/sub 4/ can be determined with accuracy of about 0.002%. The comparison method between peak heights is as accurate as that between areas, when the uniformity of magnetic field and T/sub 2/ are not questionable. In the case of chemical shift movable due to content, the substance can be determined by the position of the chemical shift. Oil and water contents in rape-seed, peanuts, and sunflower-seed are determined by measuring T/sub 1/ with 90 deg pulses.

Stable Isotope Quantitative N-Glycan Analysis by Liquid Separation Techniques and Mass Spectrometry.

Science.gov (United States)

Mittermayr, Stefan; Albrecht, Simone; Váradi, Csaba; Millán-Martín, Silvia; Bones, Jonathan

2017-01-01

Liquid phase separation analysis and subsequent quantitation remains a challenging task for protein-derived oligosaccharides due to their inherent structural complexity and diversity. Incomplete resolution or co-detection of multiple glycan species complicates peak area-based quantitation and associated statistical analysis when optical detection methods are used. The approach outlined herein describes the utilization of stable isotope variants of commonly used fluorescent tags that allow for mass-based glycan identification and relative quantitation following separation by liquid chromatography (LC) or capillary electrophoresis (CE). Comparability assessment of glycoprotein-derived oligosaccharides is performed by derivatization with commercially available isotope variants of 2-aminobenzoic acid or aniline and analysis by LC- and CE-mass spectrometry. Quantitative information is attained from the extracted ion chromatogram/electropherogram ratios generated from the light and heavy isotope clusters.

Quantitative analysis of myocardial tissue with digital autofluorescence microscopy

DEFF Research Database (Denmark)

Jensen, Thomas; Holten-Rossing, Henrik; Svendsen, Ida M H

2016-01-01

to that of hematoxylin and eosin staining in conventional pathology. This study presents an automated fluorescence-based microscopy approach providing highly detailed morphological data from unstained microsections. This data may provide a basic histological starting point from which further digital analysis including...... staining may benefit. METHODS: This study explores the inherent tissue fluorescence, also known as autofluorescence, as a mean to quantitate cardiac tissue components in histological microsections. Data acquisition using a commercially available whole slide scanner and an image-based quantitation algorithm......BACKGROUND: The opportunity offered by whole slide scanners of automated histological analysis implies an ever increasing importance of digital pathology. To go beyond the importance of conventional pathology, however, digital pathology may need a basic histological starting point similar...

Fabrication of tuning-fork based AFM and STM tungsten probe

KAUST Repository

Al-Falih, Hisham

2011-12-01

We compare the sharpness of tungsten probe tips produced by the single-step and two-step dynamic electrochemical etching processes. A small radius of curvature (RoC) of 25 nm or less was routinely obtained when the two-step electrochemical etching (TEE) process was adopted, while the smallest achievable RoC was ∼10 nm, rendering it suitable for atomic force microscopy (AFM) or scanning tunneling microscopy (STM) applications. © 2011 IEEE.

CHARACTERIZATION OF SURFACE OF THE (010 FACE OF BORAX CRYSTALS USING EX SITU ATOMIC FORCE MICROSCOPY (AFM:

Directory of Open Access Journals (Sweden)

Suharso Suharso

2010-06-01

Full Text Available The surface topology of borax crystals grown at a relative supersaturation of 0.21 has been investigated using ex situ atomic force microscopy (AFM. It was found that the cleavage of borax crystals along the (010 face planes has features of the cleavage of layered compounds, exhibiting cleavage steps of low heights. The step heights of the cleavage of the (010 face of borax crystal are from one unit cell to three unit cells of this face.   Keywords: AFM, cleavage, borax.

Quantitative analysis of target components by comprehensive two-dimensional gas chromatography

NARCIS (Netherlands)

Mispelaar, V.G. van; Tas, A.C.; Smilde, A.K.; Schoenmakers, P.J.; Asten, A.C. van

2003-01-01

Quantitative analysis using comprehensive two-dimensional (2D) gas chromatography (GC) is still rarely reported. This is largely due to a lack of suitable software. The objective of the present study is to generate quantitative results from a large GC x GC data set, consisting of 32 chromatograms.

Role of image analysis in quantitative characterisation of nuclear fuel materials

International Nuclear Information System (INIS)

Dubey, J.N.; Rao, T.S.; Pandey, V.D.; Majumdar, S.

2005-01-01

Image analysis is one of the important techniques, widely used for materials characterization. It provides the quantitative estimation of the microstructural features present in the material. This information is very much valuable for finding out the criteria for taking up the fuel for high burn up. Radiometallurgy Division has been carrying out development and fabrication of plutonium related fuels for different type of reactors viz. Purnima, Fast Breeder Test Reactor (FBTR), Prototype Fast Breeder Reactor (PFBR), Boiling Water Reactor (BWR), Advanced Heavy Water Reactor (AHWR), Pressurised Heavy Water Reactor (PHWR) and KAMINI Reactor. Image analysis has been carried out on microstructures of PHWR, AHWR, FBTR and KAMINI fuels. Samples were prepared as per standard ASTM metallographic procedure. Digital images of the microstructure of these specimens were obtained using CCD camera, attached to the optical microscope. These images are stores on computer and used for detection and analysis of features of interest with image analysis software. Quantitative image analysis technique has been standardised and used for finding put type of the porosity, its size, shape and distribution in the above sintered oxide and carbide fuels. This technique has also been used for quantitative estimation of different phases present in KAMINI fuel. Image analysis results have been summarised and presented in this paper. (author)

Micro photometer's automation for quantitative spectrograph analysis

International Nuclear Information System (INIS)

Gutierrez E, C.Y.A.

1996-01-01

A Microphotometer is used to increase the sharpness of dark spectral lines. Analyzing these lines one sample content and its concentration could be determined and the analysis is known as Quantitative Spectrographic Analysis. The Quantitative Spectrographic Analysis is carried out in 3 steps, as follows. 1. Emulsion calibration. This consists of gauging a photographic emulsion, to determine the intensity variations in terms of the incident radiation. For the procedure of emulsion calibration an adjustment with square minimum to the data obtained is applied to obtain a graph. It is possible to determine the density of dark spectral line against the incident light intensity shown by the microphotometer. 2. Working curves. The values of known concentration of an element against incident light intensity are plotted. Since the sample contains several elements, it is necessary to find a work curve for each one of them. 3. Analytical results. The calibration curve and working curves are compared and the concentration of the studied element is determined. The automatic data acquisition, calculation and obtaining of resulting, is done by means of a computer (PC) and a computer program. The conditioning signal circuits have the function of delivering TTL levels (Transistor Transistor Logic) to make the communication between the microphotometer and the computer possible. Data calculation is done using a computer programm

[Rapid analysis of suppositories by quantitative 1H NMR spectroscopy].

Science.gov (United States)

Abramovich, R A; Kovaleva, S A; Goriainov, S V; Vorob'ev, A N; Kalabin, G A

2012-01-01

Rapid analysis of suppositories with ibuprofen and arbidol by quantitative 1H NMR spectroscopy was performed. Optimal conditions for the analysis were developed. The results are useful for design of rapid methods for quality control of suppositories with different components

Quantitative EDXS analysis of organic materials using the ζ-factor method

International Nuclear Information System (INIS)

Fladischer, Stefanie; Grogger, Werner

2014-01-01

In this study we successfully applied the ζ-factor method to perform quantitative X-ray analysis of organic thin films consisting of light elements. With its ability to intrinsically correct for X-ray absorption, this method significantly improved the quality of the quantification as well as the accuracy of the results compared to conventional techniques in particular regarding the quantification of light elements. We describe in detail the process of determining sensitivity factors (ζ-factors) using a single standard specimen and the involved parameter optimization for the estimation of ζ-factors for elements not contained in the standard. The ζ-factor method was then applied to perform quantitative analysis of organic semiconducting materials frequently used in organic electronics. Finally, the results were verified and discussed concerning validity and accuracy. - Highlights: • The ζ-factor method is used for quantitative EDXS analysis of light elements. • We describe the process of determining ζ-factors from a single standard in detail. • Organic semiconducting materials are successfully quantified

A study of AFM-based scratch process on polycarbonate surface and grating application

International Nuclear Information System (INIS)

Choi, Chul Hyun; Lee, Dong Jin; Sung, Jun-Ho; Lee, Min Woo; Lee, Seung-Gol; Park, Se-Geun; Lee, El-Hang; O, Beom-Hoan

2010-01-01

We report on the possibility of applying atomic force microscope (AFM) lithography to draw micro/nano-structures on the surface of a polycarbonate (PC) substrate. We also fabricated a grating structure on the PC surface using the scratch method. An AFM silicon tip coated with a diamond layer was utilized as a cutting tool to scratch the surface of the sample. In order to obtain pattern depth deeper than the control method of interaction force, we used a scanner movement method which the sample scanner moves along the Z-axis. A grating of 100 μm x 150 μm was fabricated by the step and repeat method wherein the sample stage is moved in the direction of the XY-axis. The period and the depth of the grating are 500 and 50 nm, respectively. Light of 632.8 nm wavelength was diffracted on the surface of the PC substrate.

AFM-based detection of glycocalyx degradation and endothelial stiffening in the db/db mouse model of diabetes.

Science.gov (United States)

Targosz-Korecka, Marta; Jaglarz, Magdalena; Malek-Zietek, Katarzyna E; Gregorius, Aleksandra; Zakrzewska, Agnieszka; Sitek, Barbara; Rajfur, Zenon; Chlopicki, Stefan; Szymonski, Marek

2017-11-21

Degradation of the glycocalyx and stiffening of endothelium are important pathophysiological components of endothelial dysfunction. However, to our knowledge, these events have not been investigated in tandem in experimental diabetes. Here, the mechanical properties of the glycocalyx and endothelium in ex vivo mouse aorta were determined simultaneously in indentation experiments with an atomic force microscope (AFM) for diabetic db/db and control db/+ mice at ages of 11-19 weeks. To analyze highly heterogeneous aorta samples, we developed a tailored classification procedure of indentation data based on a bi-layer brush model supplemented with Hertz model for quantification of nanomechanics of endothelial regions with and without the glycocalyx surface. In db/db mice, marked endothelial stiffening and reduced glycocalyx coverage were present already in 11-week-old mice and persisted in older animals. In contrast, reduction of the effective glycocalyx length was progressive and was most pronounced in 19-week-old db/db mice. The reduction of the glycocalyx length correlated with an increasing level of glycated haemoglobin and decreased endothelial NO production. In conclusion, AFM nanoindentation analysis revealed that stiffening of endothelial cells and diminished glycocalyx coverage occurred in early diabetes and were followed by the reduction of the glycocalyx length that correlated with diabetes progression.

XPS, UV–vis spectroscopy and AFM studies on removal mechanisms of Si-face SiC wafer chemical mechanical polishing (CMP)

International Nuclear Information System (INIS)

Zhou, Yan; Pan, Guoshun; Shi, Xiaolei; Xu, Li; Zou, Chunli; Gong, Hua; Luo, Guihai

2014-01-01

Highlights: • CMP removal mechanism of Si-face SiC wafer is investigated through XPS analysis. • UV–vis spectroscopy is used to study CMP removal mechanisms. • CMP removal model of Si-face SiC wafer is proposed. • The variations of atomic step morphology on ultra-smooth surface via AFM is studied. - Abstract: Chemical mechanical polishing (CMP) removal mechanisms of on-axis Si-face SiC wafer have been investigated through X-ray photoelectron spectroscopy (XPS), UV–visible (UV–vis) spectroscopy and atomic force microscopy (AFM). XPS results indicate that silicon oxide is formed on Si-face surface polished by the slurry including oxidant H 2 O 2 , but not that after immersing in H 2 O 2 solution. UV–vis spectroscopy curves prove that • OH hydroxyl radical could be generated only under CMP polishing by the slurry including H 2 O 2 and abrasive, so as to promote oxidation of Si-face to realize the effective removal; meanwhile, alkali KOH during CMP could induce the production of more radicals to improve the removal. On the other side, ultra-smooth polished surface with atomic step structure morphology and extremely low Ra of about 0.06 nm (through AFM) is obtained using the developed slurry with silica nanoparticle abrasive. Through investigating the variations of the atomic step morphology on the surface polished by different slurries, it's reveals that CMP removal mechanism involves a simultaneous process of surface chemical reaction and nanoparticle atomic scale abrasion

Quantitative analysis by computer controlled X-ray fluorescence spectrometer

International Nuclear Information System (INIS)

Balasubramanian, T.V.; Angelo, P.C.

1981-01-01

X-ray fluorescence spectroscopy has become a widely accepted method in the metallurgical field for analysis of both minor and major elements. As encountered in many other analytical techniques, the problem of matrix effect generally known as the interelemental effects is to be dealt with effectively in order to make the analysis accurate. There are several methods by which the effects of matrix on the analyte are minimised or corrected for and the mathematical correction is one among them. In this method the characteristic secondary X-ray intensities are measured from standard samples and correction coefficients. If any, for interelemental effects are evaluated by mathematical calculations. This paper describes attempts to evaluate the correction coefficients for interelemental effects by multiple linear regression programmes using a computer for the quantitative analysis of stainless steel and a nickel base cast alloy. The quantitative results obtained using this method for a standard stainless steel sample are compared with the given certified values. (author)

PIQMIe: A web server for semi-quantitative proteomics data management and analysis

NARCIS (Netherlands)

A. Kuzniar (Arnold); R. Kanaar (Roland)

2014-01-01

textabstractWe present the Proteomics Identifications and Quantitations Data Management and Integration Service or PIQMIe that aids in reliable and scalable data management, analysis and visualization of semi-quantitative mass spectrometry based proteomics experiments. PIQMIe readily integrates

Issues in Quantitative Analysis of Ultraviolet Imager (UV) Data: Airglow

Science.gov (United States)

Germany, G. A.; Richards, P. G.; Spann, J. F.; Brittnacher, M. J.; Parks, G. K.

1999-01-01

The GGS Ultraviolet Imager (UVI) has proven to be especially valuable in correlative substorm, auroral morphology, and extended statistical studies of the auroral regions. Such studies are based on knowledge of the location, spatial, and temporal behavior of auroral emissions. More quantitative studies, based on absolute radiometric intensities from UVI images, require a more intimate knowledge of the instrument behavior and data processing requirements and are inherently more difficult than studies based on relative knowledge of the oval location. In this study, UVI airglow observations are analyzed and compared with model predictions to illustrate issues that arise in quantitative analysis of UVI images. These issues include instrument calibration, long term changes in sensitivity, and imager flat field response as well as proper background correction. Airglow emissions are chosen for this study because of their relatively straightforward modeling requirements and because of their implications for thermospheric compositional studies. The analysis issues discussed here, however, are identical to those faced in quantitative auroral studies.

Critical appraisal of semi-quantitative analysis of 2-deoxyglucose autoradiograms

Energy Technology Data Exchange (ETDEWEB)

Kelly, P T; McCulloch, J [Glasgow Univ. (UK)

1983-06-13

Semi-quantitative analysis (e.g. optical density ratios) of (/sup 14/C)2-deoxyglucose autoradiograms is widely used in neuroscience research. The authors demonstrate that a fixed ratio of /sup 14/C-concentrations in the CNS does not yield a constant optical density ratio but is dependent upon the exposure time in the preparation of the autoradiograms and the absolute amounts of /sup 14/C from which the concentration ratio is derived. The failure of a fixed glucose utilization ratio to result in a constant optical density ratio represents a major interpretative difficulty in investigations where only semi-quantitative analysis of (/sup 14/C)2-deoxyglucose autoradiograms is undertaken.

Quantitative-genetic analysis of wing form and bilateral asymmetry ...

Indian Academy of Sciences (India)

Unknown

lines; Procrustes analysis; wing shape; wing size. ... Models of stochastic gene expression pre- dict that intrinsic noise ... Quantitative parameters of wing size and shape asymmetries ..... the residuals of a regression on centroid size produced.

Quantitative Analysis of Complex Tropical Forest Stands: A Review ...

African Journals Online (AJOL)

FIRST LADY

The importance of data analysis in quantitative assessment of natural resources .... Data collection design is an important process in complex forest statistical ... Ideally, the sample size should be equal among groups and sufficiently large.

Transportation and quantitative analysis of socio-economic development of relations

Science.gov (United States)

Chen, Yun

2017-12-01

Transportation has a close relationship with socio-economic. This article selects the indicators which can measure the development of transportation and socio-economic, using the method of correlation analysis, regression analysis, intensity of transportation analysis and transport elastic analysis, to analyze the relationship between them quantitatively, so that it has the fact guiding sense in the national development planning for the future.

Multivariate data analysis approach to understand magnetic properties of perovskite manganese oxides

International Nuclear Information System (INIS)

Imamura, N.; Mizoguchi, T.; Yamauchi, H.; Karppinen, M.

2008-01-01

Here we apply statistical multivariate data analysis techniques to obtain some insights into the complex structure-property relations in antiferromagnetic (AFM) and ferromagnetic (FM) manganese perovskite systems, AMnO 3 . The 131 samples included in the present analyses are described by 21 crystal-structure or crystal-chemical (CS/CC) parameters. Principal component analysis (PCA), carried out separately for the AFM and FM compounds, is used to model and evaluate the various relationships among the magnetic properties and the various CS/CC parameters. Moreover, for the AFM compounds, PLS (partial least squares projections to latent structures) analysis is performed so as to predict the magnitude of the Neel temperature on the bases of the CS/CC parameters. Finally, so-called PLS-DA (PLS discriminant analysis) method is employed to find out the most influential/characteristic CS/CC parameters that differentiate the two classes of compounds from each other. - Graphical abstract: Statistical multivariate data analysis techniques are applied to detect structure-property relations in antiferromagnetic (AFM) and ferromagnetic (FM) manganese perovskites. For AFM compounds, partial least squares projections to latent structures analysis predict the magnitude of the Neel temperature on the bases of structural parameters only. Moreover, AFM and FM compounds are well separated by means of so-called partial least squares discriminant analysis method

Quantitative high-resolution genomic analysis of single cancer cells.

Science.gov (United States)

Hannemann, Juliane; Meyer-Staeckling, Sönke; Kemming, Dirk; Alpers, Iris; Joosse, Simon A; Pospisil, Heike; Kurtz, Stefan; Görndt, Jennifer; Püschel, Klaus; Riethdorf, Sabine; Pantel, Klaus; Brandt, Burkhard

2011-01-01

During cancer progression, specific genomic aberrations arise that can determine the scope of the disease and can be used as predictive or prognostic markers. The detection of specific gene amplifications or deletions in single blood-borne or disseminated tumour cells that may give rise to the development of metastases is of great clinical interest but technically challenging. In this study, we present a method for quantitative high-resolution genomic analysis of single cells. Cells were isolated under permanent microscopic control followed by high-fidelity whole genome amplification and subsequent analyses by fine tiling array-CGH and qPCR. The assay was applied to single breast cancer cells to analyze the chromosomal region centred by the therapeutical relevant EGFR gene. This method allows precise quantitative analysis of copy number variations in single cell diagnostics.

Quantitative Proteomic Analysis of Sulfolobus solfataricus Membrane Proteins

NARCIS (Netherlands)

Pham, T.K.; Sierocinski, P.; Oost, van der J.; Wright, P.C.

2010-01-01

A quantitative proteomic analysis of the membrane of the archaeon Sulfolobus solfataricus P2 using iTRAQ was successfully demonstrated in this technical note. The estimated number of membrane proteins of this organism is 883 (predicted based on Gravy score), corresponding to 30 % of the total

Quantitative X-ray analysis of biological fluids: the microdroplet technique

International Nuclear Information System (INIS)

Roinel, N.

1988-01-01

X-ray microanalysis can be used to quantitatively determine the elemental composition of microvolumes of biological fluids. This article describes the various steps in preparation of microdroplets for analysis: The manufacturing of micropipettes, the preparation of the specimen support, the deposition of droplets on the support, shock-freezing, and lyophilization. Examples of common artifacts (incomplete rehydration prior to freezing or partial rehydration after lyophilization) are demonstrated. Analysis can be carried out either by wavelength-dispersive analysis, which is the most sensitive method, or by energy-dispersive analysis, which is more commonly available. The minimum detectable concentration is 0.05 mmol.liter-1 for 0.1-nl samples analyzed by wavelength-dispersive spectrometry and 0.5-1 mmol.liter-1 for samples analyzed by energy-dispersive spectrometry. A major problem, especially in wavelength-dispersive analysis, where high beam currents are used, is radiation damage to the specimen; in particular chloride (but also other elements) can be lost. Quantitative analysis requires the use of standard solutions with elemental concentration in the same range as those present in the specimen

BOREAS AFM-06 Mean Wind Profile Data

Science.gov (United States)

Wilczak, James; Hall, Forrest G. (Editor); Newcomer, Jeffrey A. (Editor); Smith, David E. (Technical Monitor)

2000-01-01

The Boreal Ecosystem-Atmosphere Study (BOREAS) Airborne Fluxes and Meteorology (AFM)-6 team from the National Oceanic and Atmospheric Administration/Environment Technology Laboratory (NOAA/ETL) operated a 915-MHz wind/Radio Acoustic Sounding System (RASS) profiler system in the Southern Study Area (SSA) near the Old Jack Pine (OJP) tower from 21 May 1994 to 20 Sep 1994. The data set provides wind profiles at 38 heights, containing the variables of wind speed; wind direction; and the u-, v-, and w-components of the total wind. The data are stored in tabular ASCII files. The mean wind profile data are available from the Earth Observing System Data and Information System (EOSDIS) Oak Ridge National Laboratory (ORNL) Distributed Active Archive Center (DAAC). The data files are available on a CD-ROM (see document number 20010000884).

Polymorphism of amyloid fibrils formed by a peptide from the yeast prion protein Sup35: AFM and Tip-Enhanced Raman Scattering studies

Energy Technology Data Exchange (ETDEWEB)

Krasnoslobodtsev, Alexey V., E-mail: akrasnos@unomaha.edu [Department of Pharmaceutical Sciences, University of Nebraska Medical Center, 986025 Nebraska Medical Center, Omaha, NE 68198 (United States); Department of Physics, University of Nebraska Omaha, Omaha, NE 68182 (United States); Deckert-Gaudig, Tanja [IPHT-Leibniz Institute of Photonic Technology, Albert-Einstein-Str. 9, D-07745 Jena (Germany); Zhang, Yuliang [Department of Pharmaceutical Sciences, University of Nebraska Medical Center, 986025 Nebraska Medical Center, Omaha, NE 68198 (United States); Deckert, Volker [IPHT-Leibniz Institute of Photonic Technology, Albert-Einstein-Str. 9, D-07745 Jena (Germany); Institute for Physical Chemistry and Abbe Center of Photonics, University of Jena, Helmholtzweg 4, D-07743 Jena (Germany); Lyubchenko, Yuri L., E-mail: ylyubchenko@unmc.edu [Department of Pharmaceutical Sciences, University of Nebraska Medical Center, 986025 Nebraska Medical Center, Omaha, NE 68198 (United States)

2016-06-15

Aggregation of prion proteins is the cause of various prion related diseases. The infectious form of prions, amyloid aggregates, exist as multiple strains. The strains are thought to represent structurally different prion protein molecules packed into amyloid aggregates, but the knowledge on the structure of different types of aggregates is limited. Here we report on the use of AFM (Atomic Force Microscopy) and TERS (Tip-Enhanced Raman Scattering) to study morphological heterogeneity and access underlying conformational features of individual amyloid aggregates. Using AFM we identified the morphology of amyloid fibrils formed by the peptide (CGNNQQNY) from the yeast prion protein Sup35 that is critically involved in the aggregation of the full protein. TERS results demonstrate that morphologically different amyloid fibrils are composed of a distinct set of conformations. Fibrils formed at pH 5.6 are composed of a mixture of peptide conformations (β-sheets, random coil and α-helix) while fibrils formed in pH~2 solution primarily have β-sheets. Additionally, peak positions in the amide III region of the TERS spectra suggested that peptides have parallel arrangement of β-sheets for pH~2 fibrils and antiparallel arrangement for fibrils formed at pH 5.6. We also developed a methodology for detailed analysis of the peptide secondary structure by correlating intensity changes of Raman bands in different regions of TERS spectra. Such correlation established that structural composition of peptides is highly localized with large contribution of unordered secondary structures on a fibrillar surface. - Highlights: • Amyloid polymorphs were characterized by AFM and TERS. • A mixture of peptide secondary structures in fibrils were identified using TERS. • TERS recognizes packing arrangement (parallel versus antiparallel) of peptides. • TERS is a powerful tool for high resolution structural analysis of fibrils.

Method of quantitative x-ray diffractometric analysis of Ta-Ta2C system

International Nuclear Information System (INIS)

Gavrish, A.A.; Glazunov, M.P.; Korolev, Yu.M.; Spitsyn, V.I.; Fedoseev, G.K.

1976-01-01

The syste86 Ta-Ta 2 C has beemonsidered because of specific features of diffraction patterns of the components, namely, overlapping of the most intensive reflexes of both phases. The method of standard binary system has been used for quantitative analysis. Because of overlapping of the intensive reflexes dsub(1/01)=2.36(Ta 2 C) and dsub(110)=2.33(Ta), the other, most intensive, reflexes have been used for quantitative determination of Ta 2 C and Ta: dsub(103)=1.404 A for tantalum subcarbide and dsub(211)=1.35A for tantalum. Besides, the TaTa 2 C phases have been determined quantitatively with the use of another pair of reflexes: dsub(102)=1.82 A for Ta 2 C and dsub(200)=1.65 A for tantalum. The agreement between the results obtained while performing the quantitative phase analysis is good. To increase reliability and accuracy of the quantitative determination of Ta and Ta 2 C, it is expedient to carry out the analysis with the use of two above-mentioned pairs of reflexes located in different regions of the diffraction spectrum. Thus, the procedure of quantitative analysis of Ta and Ta 2 C in different ratios has been developed taking into account the specific features of the diffraction patterns of these components as well as the ability of Ta 2 C to texture in the process of preparation

A Quantitative Analysis of the Behavioral Checklist of the Movement ABC Motor Test

Science.gov (United States)

Ruiz, Luis Miguel; Gomez, Marta; Graupera, Jose Luis; Gutierrez, Melchor; Linaza, Jose Luis

2007-01-01

The fifth section of the Henderson and Sugden's Movement ABC Checklist is part of the general Checklist that accompanies The Movement ABC Battery. The authors maintain that the analysis of this section must be mainly qualitative instead of quantitative. The main objective of this study was to employ a quantitative analysis of this behavioural…

Quantitative assessment of in-solution digestion efficiency identifies optimal protocols for unbiased protein analysis

DEFF Research Database (Denmark)

Leon, Ileana R; Schwämmle, Veit; Jensen, Ole N

2013-01-01

a combination of qualitative and quantitative LC-MS/MS methods and statistical data analysis. In contrast to previous studies we employed both standard qualitative as well as data-independent quantitative workflows to systematically assess trypsin digestion efficiency and bias using mitochondrial protein...... conditions (buffer, RapiGest, deoxycholate, urea), and two methods for removal of detergents prior to analysis of peptides (acid precipitation or phase separation with ethyl acetate). Our data-independent quantitative LC-MS/MS workflow quantified over 3700 distinct peptides with 96% completeness between all...... protocols and replicates, with an average 40% protein sequence coverage and an average of 11 peptides identified per protein. Systematic quantitative and statistical analysis of physicochemical parameters demonstrated that deoxycholate-assisted in-solution digestion combined with phase transfer allows...

Investigation of the resistive switching in Ag{sub x}AsS{sub 2} layer by conductive AFM

Energy Technology Data Exchange (ETDEWEB)

Zhang, Bo [Department of General and Inorganic Chemistry, Faculty of Chemical Technology, University of Pardubice, Studentska 573, Pardubice, 532 10 Czech Republic (Czech Republic); Kutalek, Petr [Joint Laboratory of Solid State Chemistry of Institute of Macromolecular Chemistry Academy of Sciences of Czech Republic, v.v.i., and University of Pardubice, University of Pardubice, Studentska 573, Pardubice, 532 10 (Czech Republic); Knotek, Petr [Department of General and Inorganic Chemistry, Faculty of Chemical Technology, University of Pardubice, Studentska 573, Pardubice, 532 10 Czech Republic (Czech Republic); Hromadko, Ludek; Macak, Jan M. [Center of Materials and Nanotechnologies, Faculty of Chemical Technology, University of Pardubice, Nam. Cs. Legii 565, Pardubice, 53002 (Czech Republic); Wagner, Tomas, E-mail: tomas.wagner@upce.cz [Department of General and Inorganic Chemistry, Faculty of Chemical Technology, University of Pardubice, Studentska 573, Pardubice, 532 10 Czech Republic (Czech Republic); Center of Materials and Nanotechnologies, Faculty of Chemical Technology, University of Pardubice, Nam. Cs. Legii 565, Pardubice, 53002 (Czech Republic)

2016-09-30

Highlights: • The resistive switching was studied from topological maps and spread current maps by conductive AFM. • Both surface particles and filaments were created under bias from conductive AFM. • The combination of topological map and spread current map proves the current did not flow through surface particles. • A model, consisting of interactions between charge carriers and Ag ions, were introduced to explain the experiment phenomena. - Abstract: In this paper, a study of resistive switching in Ag{sub x}AsS{sub 2} layer, based on a utilization of conductive atomic force microscope (AFM), is reported. As the result of biasing, two distinct regions were created on the surface (the conductive region and non-conductive region). Both were analysed from the spread current maps. The volume change, corresponding to the growth of Ag particles, was derived from the topological maps, recorded simultaneously with the current maps. Based on the results, a model explaining the mechanism of the Ag particle and Ag filament formation was proposed from the distribution of charge carriers and Ag ions.

Chemical Fingerprint Analysis and Quantitative Analysis of Rosa rugosa by UPLC-DAD

Directory of Open Access Journals (Sweden)

Sanawar Mansur

2016-12-01

Full Text Available A method based on ultra performance liquid chromatography with a diode array detector (UPLC-DAD was developed for quantitative analysis of five active compounds and chemical fingerprint analysis of Rosa rugosa. Ten batches of R. rugosa collected from different plantations in the Xinjiang region of China were used to establish the fingerprint. The feasibility and advantages of the used UPLC fingerprint were verified for its similarity evaluation by systematically comparing chromatograms with professional analytical software recommended by State Food and Drug Administration (SFDA of China. In quantitative analysis, the five compounds showed good regression (R2 = 0.9995 within the test ranges, and the recovery of the method was in the range of 94.2%–103.8%. The similarities of liquid chromatography fingerprints of 10 batches of R. rugosa were more than 0.981. The developed UPLC fingerprint method is simple, reliable, and validated for the quality control and identification of R. rugosa. Additionally, simultaneous quantification of five major bioactive ingredients in the R. rugosa samples was conducted to interpret the consistency of the quality test. The results indicated that the UPLC fingerprint, as a characteristic distinguishing method combining similarity evaluation and quantification analysis, can be successfully used to assess the quality and to identify the authenticity of R. rugosa.

Phase analysis in duplex stainless steel: comparison of EBSD and quantitative metallography methods

International Nuclear Information System (INIS)

Michalska, J; Chmiela, B

2014-01-01

The purpose of the research was to work out the qualitative and quantitative analysis of phases in DSS in as-received state and after thermal aging. For quantitative purposes, SEM observations, EDS analyses and electron backscattered diffraction (EBSD) methods were employed. Qualitative analysis of phases was performed by two methods: EBSD and classical quantitative metallography. A juxtaposition of different etchants for the revealing of microstructure and brief review of sample preparation methods for EBSD studies were presented. Different ways of sample preparation were tested and based on these results a detailed methodology of DSS phase analysis was developed including: surface finishing, selective etching methods and image acquisition. The advantages and disadvantages of applied methods were pointed out and compared the accuracy of the analysis phase performed by both methods

Comparative study of standard space and real space analysis of quantitative MR brain data.

Science.gov (United States)

Aribisala, Benjamin S; He, Jiabao; Blamire, Andrew M

2011-06-01

To compare the robustness of region of interest (ROI) analysis of magnetic resonance imaging (MRI) brain data in real space with analysis in standard space and to test the hypothesis that standard space image analysis introduces more partial volume effect errors compared to analysis of the same dataset in real space. Twenty healthy adults with no history or evidence of neurological diseases were recruited; high-resolution T(1)-weighted, quantitative T(1), and B(0) field-map measurements were collected. Algorithms were implemented to perform analysis in real and standard space and used to apply a simple standard ROI template to quantitative T(1) datasets. Regional relaxation values and histograms for both gray and white matter tissues classes were then extracted and compared. Regional mean T(1) values for both gray and white matter were significantly lower using real space compared to standard space analysis. Additionally, regional T(1) histograms were more compact in real space, with smaller right-sided tails indicating lower partial volume errors compared to standard space analysis. Standard space analysis of quantitative MRI brain data introduces more partial volume effect errors biasing the analysis of quantitative data compared to analysis of the same dataset in real space. Copyright © 2011 Wiley-Liss, Inc.

Statistical shape analysis using 3D Poisson equation--A quantitatively validated approach.

Science.gov (United States)

Gao, Yi; Bouix, Sylvain

2016-05-01

Statistical shape analysis has been an important area of research with applications in biology, anatomy, neuroscience, agriculture, paleontology, etc. Unfortunately, the proposed methods are rarely quantitatively evaluated, and as shown in recent studies, when they are evaluated, significant discrepancies exist in their outputs. In this work, we concentrate on the problem of finding the consistent location of deformation between two population of shapes. We propose a new shape analysis algorithm along with a framework to perform a quantitative evaluation of its performance. Specifically, the algorithm constructs a Signed Poisson Map (SPoM) by solving two Poisson equations on the volumetric shapes of arbitrary topology, and statistical analysis is then carried out on the SPoMs. The method is quantitatively evaluated on synthetic shapes and applied on real shape data sets in brain structures. Copyright © 2016 Elsevier B.V. All rights reserved.

In situ EC-AFM study of the effect of nanocrystals on the passivation and pit initiation in an Al-based metallic glass

International Nuclear Information System (INIS)

Zhang, S.D.; Liu, Z.W.; Wang, Z.M.; Wang, J.Q.

2014-01-01

Highlights: • The nanoscale corrosion on Al-rich glass was characterised by in situ EC-AFM. • The nanocrystals were identified from amorphous matrix by tapping mode AFM. • The formation of corrosion products is associated with the galvanic coupling. • The nanocrystals changed the local structure and component of the passive film. - Abstract: The effect of nanocrystals on pit initiation in metallic glasses is an unresolved issue. The passive film formation and pit initiation in the Al–Ni–Ce metallic glass were investigated using in situ electrochemical atomic force microscope (EC-AFM). The α-Al nanophases were identified from the amorphous matrix based upon the phase imaging in the tapping mode AFM. In the early stage of the passive film formation, the corrosion products Al(OH) 3 formed on the α-Al nanoparticles due to the galvanic coupling. The corrosion products incorporated into the passive film changed the local structure and component of the passive film, lowering its stability

Laser activation-modification of semiconductor surfaces (LAMSS) of 1-alkenes on silicon: A ToF-SIMS, chemometrics, and AFM analysis

International Nuclear Information System (INIS)

Pei Lei; Jiang Guilin; Davis, Robert C.; Shaver, Jeremy M.; Smentkowski, Vincent S.; Asplund, Matthew C.; Linford, Matthew R.

2007-01-01

Laser-activation-modification of semiconductor surfaces (LAMSS) was carried out on silicon with a series of 1-alkenes. These laser spots were studied by time of flight secondary ion mass spectrometry (ToF-SIMS). The resulting spectra were analyzed using the multivariate curve resolution (MCR) method within the Automated eXpert Spectral Image Analysis (AXSIA) toolkit, and also by MCR and cluster analysis using commercially available toolboxes for Matlab: the PLS T oolbox and the MIA T oolbox, respectively. AXSIA based MCR generally finds three components for the spectral images: one for the background and two for the laser-activated spots, for both the positive and negative ion images. The negative ion component spectra from the spots show increased carbon and hydrogen signals compared to oxygen. They also show reduced chlorine and fluorine (contamination) peaks. In order to compare AXSIA-MCR results from different images, the AXSIA component spectra of different spots were further analyzed by principal components analysis (PCA). PCA of all of the negative ion components shows that component 1 is chemically distinct from components 2 and 3. PCA of all of the positive ion components yields the same result. The loadings plots of this PCA analysis confirm that component 1 generally contains fragments expected from the substrate, while components 2 and 3 contain fragments expected from an overlayer composed of alkyl chains in the spots. A comparison of the two MCR analyses suggests that roughly the same information can be obtained from AXSIA, which is not commercially available, and the PLS T oolbox. Cluster analysis of the data also clearly separates the spots from the backgrounds. A key finding from these analyses is that the degree of surface functionalization in a LAMSS spot appears to decrease radially from the center of the spot. Finally, a comparison of atomic force microscopy (AFM) of the spots versus the AXSIA analysis of the ToF-SIMS data produced another

Laser activation-modification of semiconductor surfaces (LAMSS) of 1-alkenes on silicon: A ToF-SIMS, chemometrics, and AFM analysis

Energy Technology Data Exchange (ETDEWEB)

Pei Lei [Department of Chemistry and Biochemistry, Brigham Young University, Provo, UT 84602 (United States); Jiang Guilin [Department of Chemistry and Biochemistry, Brigham Young University, Provo, UT 84602 (United States); Department of Bioengineering, University of Washington, Seattle, WA (United States); Davis, Robert C. [Department of Physics and Astronomy, Brigham Young University, Provo, UT 84602 (United States); Shaver, Jeremy M. [Eigenvector Research Inc., Wenatchee, WA 98801 (United States); Smentkowski, Vincent S. [GE Global Research, 1 Research Circle, Niskayuna, NY (United States); Asplund, Matthew C. [Department of Chemistry and Biochemistry, Brigham Young University, Provo, UT 84602 (United States); Linford, Matthew R. [Department of Chemistry and Biochemistry, Brigham Young University, Provo, UT 84602 (United States)]. E-mail: mrlinford@chem.byu.edu

2007-04-15

Laser-activation-modification of semiconductor surfaces (LAMSS) was carried out on silicon with a series of 1-alkenes. These laser spots were studied by time of flight secondary ion mass spectrometry (ToF-SIMS). The resulting spectra were analyzed using the multivariate curve resolution (MCR) method within the Automated eXpert Spectral Image Analysis (AXSIA) toolkit, and also by MCR and cluster analysis using commercially available toolboxes for Matlab: the PLS{sub T}oolbox and the MIA{sub T}oolbox, respectively. AXSIA based MCR generally finds three components for the spectral images: one for the background and two for the laser-activated spots, for both the positive and negative ion images. The negative ion component spectra from the spots show increased carbon and hydrogen signals compared to oxygen. They also show reduced chlorine and fluorine (contamination) peaks. In order to compare AXSIA-MCR results from different images, the AXSIA component spectra of different spots were further analyzed by principal components analysis (PCA). PCA of all of the negative ion components shows that component 1 is chemically distinct from components 2 and 3. PCA of all of the positive ion components yields the same result. The loadings plots of this PCA analysis confirm that component 1 generally contains fragments expected from the substrate, while components 2 and 3 contain fragments expected from an overlayer composed of alkyl chains in the spots. A comparison of the two MCR analyses suggests that roughly the same information can be obtained from AXSIA, which is not commercially available, and the PLS{sub T}oolbox. Cluster analysis of the data also clearly separates the spots from the backgrounds. A key finding from these analyses is that the degree of surface functionalization in a LAMSS spot appears to decrease radially from the center of the spot. Finally, a comparison of atomic force microscopy (AFM) of the spots versus the AXSIA analysis of the ToF-SIMS data produced

AFM assessment of the surface nano/microstructure on chemically damaged historical and model glasses

International Nuclear Information System (INIS)

Carmona, Noemi; Kowal, Andrzej; Rincon, Jesus-Maria; Villegas, Maria-Angeles

2010-01-01

Surface chemical damage on selected historical glasses from 13th to 19th centuries was evaluated by means of atomic force microscopy (AFM). Nano- and microstructure, roughness and topography of ancient glass samples have been compared with those of model glasses prepared by conventional melting at the laboratory with similar compositions to those most frequently found in historical glass pieces. The results obtained allow discussing the chemical degradation mechanisms in terms of the acid and/or basic chemical attack carried out by the combination of gaseous pollutants and environmental humidity. Even though deep corrosion features escape to the observation order of magnitude of the AF microscope used, the AFM technique proves to be quite useful for the study and evaluation of the most common surface pathologies of historical glasses with different compositions once submitted to natural weathering.

AFM assessment of the surface nano/microstructure on chemically damaged historical and model glasses

Energy Technology Data Exchange (ETDEWEB)

Carmona, Noemi [Centro Nacional de Investigaciones Metalurgicas, CSIC, Avda. Gregorio del Amo, 8, 28040 Madrid (Spain); Kowal, Andrzej [Institute of Catalysis and Surface Chemistry, PAN, ul. Niezapominajek 8, 30239 Cracow (Poland); Rincon, Jesus-Maria [Instituto Eduardo Torroja de Ciencias de la Construccion, CSIC, C. Serrano Galvache s/n, 28033 Madrid (Spain); Villegas, Maria-Angeles, E-mail: mariangeles.villegas@cchs.csic.es [Centro Nacional de Investigaciones Metalurgicas, CSIC, Avda. Gregorio del Amo, 8, 28040 Madrid (Spain); Instituto de Historia, Centro de Ciencias Humanas y Sociales, CSIC, C. Albasanz, 26-28, 28037 Madrid (Spain)

2010-01-15

Surface chemical damage on selected historical glasses from 13th to 19th centuries was evaluated by means of atomic force microscopy (AFM). Nano- and microstructure, roughness and topography of ancient glass samples have been compared with those of model glasses prepared by conventional melting at the laboratory with similar compositions to those most frequently found in historical glass pieces. The results obtained allow discussing the chemical degradation mechanisms in terms of the acid and/or basic chemical attack carried out by the combination of gaseous pollutants and environmental humidity. Even though deep corrosion features escape to the observation order of magnitude of the AF microscope used, the AFM technique proves to be quite useful for the study and evaluation of the most common surface pathologies of historical glasses with different compositions once submitted to natural weathering.

Quantitative analysis of background parenchymal enhancement in whole breast on MRI: Influence of menstrual cycle and comparison with a qualitative analysis.

Science.gov (United States)

Jung, Yongsik; Jeong, Seong Kyun; Kang, Doo Kyoung; Moon, Yeorae; Kim, Tae Hee

2018-06-01

We quantitatively analyzed background parenchymal enhancement (BPE) in whole breast according to menstrual cycle and compared it with a qualitative analysis method. A data set of breast magnetic resonance imaging (MRI) from 273 breast cancer patients was used. For quantitative analysis, we used semiautomated in-house software with MATLAB. From each voxel of whole breast, the software calculated BPE using following equation: [(signal intensity [SI] at 1 min 30 s after contrast injection - baseline SI)/baseline SI] × 100%. In total, 53 patients had minimal, 108 mild, 87 moderate, and 25 marked BPE. On quantitative analysis, mean BPE values were 33.1% in the minimal, 42.1% in the mild, 59.1% in the moderate, and 81.9% in the marked BPE group showing significant difference (p = .009 for minimal vs. mild, p quantitative BPE (r = 0.63, p Quantitative analysis of BPE correlated well with the qualitative BPE grade. Quantitative BPE values were lowest in the second week and highest in the fourth week. Copyright © 2018 Elsevier B.V. All rights reserved.

Towards quantitative laser-induced breakdown spectroscopy analysis of soil samples

International Nuclear Information System (INIS)

Bousquet, B.; Sirven, J.-B.; Canioni, L.

2007-01-01

A quantitative analysis of chromium in soil samples is presented. Different emission lines related to chromium are studied in order to select the best one for quantitative features. Important matrix effects are demonstrated from one soil to the other, preventing any prediction of concentration in different soils on the basis of a univariate calibration curve. Finally, a classification of the LIBS data based on a series of Principal Component Analyses (PCA) is applied to a reduced dataset of selected spectral lines related to the major chemical elements in the soils. LIBS data of heterogeneous soils appear to be widely dispersed, which leads to a reconsideration of the sampling step in the analysis process

Quantitative high-resolution genomic analysis of single cancer cells.

Directory of Open Access Journals (Sweden)

Juliane Hannemann

Full Text Available During cancer progression, specific genomic aberrations arise that can determine the scope of the disease and can be used as predictive or prognostic markers. The detection of specific gene amplifications or deletions in single blood-borne or disseminated tumour cells that may give rise to the development of metastases is of great clinical interest but technically challenging. In this study, we present a method for quantitative high-resolution genomic analysis of single cells. Cells were isolated under permanent microscopic control followed by high-fidelity whole genome amplification and subsequent analyses by fine tiling array-CGH and qPCR. The assay was applied to single breast cancer cells to analyze the chromosomal region centred by the therapeutical relevant EGFR gene. This method allows precise quantitative analysis of copy number variations in single cell diagnostics.

Quantitative risk analysis as a basis for emergency planning

Energy Technology Data Exchange (ETDEWEB)

Yogui, Regiane Tiemi Teruya [Bureau Veritas do Brasil, Rio de Janeiro, RJ (Brazil); Macedo, Eduardo Soares de [Instituto de Pesquisas Tecnologicas (IPT), Sao Paulo, SP (Brazil)

2009-07-01

Several environmental accidents happened in Brazil and in the world during the 70's and 80's. This strongly motivated the preparation for emergencies in the chemical and petrochemical industries. Environmental accidents affect the environment and the communities that are neighbor to the industrial facilities. The present study aims at subsidizing and providing orientation to develop Emergency Planning from the data obtained on Quantitative Risk Analysis, elaborated according to the Technical Standard P4.261/03 from CETESB (Sao Paulo Environmental Agency). It was observed, during the development of the research, that the data generated on these studies need a complementation and a deeper analysis, so that it is possible to use them on the Emergency Plans. The main issues that were analyzed and discussed on this study were the reevaluation of hazard identification for the emergency plans, the consequences and vulnerability analysis for the response planning, the risk communication, and the preparation to respond to the emergencies of the communities exposed to manageable risks. As a result, the study intends to improve the interpretation and use of the data deriving from the Quantitative Risk Analysis to develop the emergency plans. (author)

A Strategy for Identifying Quantitative Trait Genes Using Gene Expression Analysis and Causal Analysis

Directory of Open Access Journals (Sweden)

Akira Ishikawa

2017-11-01

Full Text Available Large numbers of quantitative trait loci (QTL affecting complex diseases and other quantitative traits have been reported in humans and model animals. However, the genetic architecture of these traits remains elusive due to the difficulty in identifying causal quantitative trait genes (QTGs for common QTL with relatively small phenotypic effects. A traditional strategy based on techniques such as positional cloning does not always enable identification of a single candidate gene for a QTL of interest because it is difficult to narrow down a target genomic interval of the QTL to a very small interval harboring only one gene. A combination of gene expression analysis and statistical causal analysis can greatly reduce the number of candidate genes. This integrated approach provides causal evidence that one of the candidate genes is a putative QTG for the QTL. Using this approach, I have recently succeeded in identifying a single putative QTG for resistance to obesity in mice. Here, I outline the integration approach and discuss its usefulness using my studies as an example.

A Strategy for Identifying Quantitative Trait Genes Using Gene Expression Analysis and Causal Analysis.

Science.gov (United States)

Ishikawa, Akira

2017-11-27

Large numbers of quantitative trait loci (QTL) affecting complex diseases and other quantitative traits have been reported in humans and model animals. However, the genetic architecture of these traits remains elusive due to the difficulty in identifying causal quantitative trait genes (QTGs) for common QTL with relatively small phenotypic effects. A traditional strategy based on techniques such as positional cloning does not always enable identification of a single candidate gene for a QTL of interest because it is difficult to narrow down a target genomic interval of the QTL to a very small interval harboring only one gene. A combination of gene expression analysis and statistical causal analysis can greatly reduce the number of candidate genes. This integrated approach provides causal evidence that one of the candidate genes is a putative QTG for the QTL. Using this approach, I have recently succeeded in identifying a single putative QTG for resistance to obesity in mice. Here, I outline the integration approach and discuss its usefulness using my studies as an example.

Quantitative analysis of patient-specific dosimetric IMRT verification

International Nuclear Information System (INIS)

Budgell, G J; Perrin, B A; Mott, J H L; Fairfoul, J; Mackay, R I

2005-01-01

Patient-specific dosimetric verification methods for IMRT treatments are variable, time-consuming and frequently qualitative, preventing evidence-based reduction in the amount of verification performed. This paper addresses some of these issues by applying a quantitative analysis parameter to the dosimetric verification procedure. Film measurements in different planes were acquired for a series of ten IMRT prostate patients, analysed using the quantitative parameter, and compared to determine the most suitable verification plane. Film and ion chamber verification results for 61 patients were analysed to determine long-term accuracy, reproducibility and stability of the planning and delivery system. The reproducibility of the measurement and analysis system was also studied. The results show that verification results are strongly dependent on the plane chosen, with the coronal plane particularly insensitive to delivery error. Unexpectedly, no correlation could be found between the levels of error in different verification planes. Longer term verification results showed consistent patterns which suggest that the amount of patient-specific verification can be safely reduced, provided proper caution is exercised: an evidence-based model for such reduction is proposed. It is concluded that dose/distance to agreement (e.g., 3%/3 mm) should be used as a criterion of acceptability. Quantitative parameters calculated for a given criterion of acceptability should be adopted in conjunction with displays that show where discrepancies occur. Planning and delivery systems which cannot meet the required standards of accuracy, reproducibility and stability to reduce verification will not be accepted by the radiotherapy community

Fluorescent foci quantitation for high-throughput analysis

Directory of Open Access Journals (Sweden)

Elena Ledesma-Fernández

2015-06-01

Full Text Available A number of cellular proteins localize to discrete foci within cells, for example DNA repair proteins, microtubule organizing centers, P bodies or kinetochores. It is often possible to measure the fluorescence emission from tagged proteins within these foci as a surrogate for the concentration of that specific protein. We wished to develop tools that would allow quantitation of fluorescence foci intensities in high-throughput studies. As proof of principle we have examined the kinetochore, a large multi-subunit complex that is critical for the accurate segregation of chromosomes during cell division. Kinetochore perturbations lead to aneuploidy, which is a hallmark of cancer cells. Hence, understanding kinetochore homeostasis and regulation are important for a global understanding of cell division and genome integrity. The 16 budding yeast kinetochores colocalize within the nucleus to form a single focus. Here we have created a set of freely-available tools to allow high-throughput quantitation of kinetochore foci fluorescence. We use this ‘FociQuant’ tool to compare methods of kinetochore quantitation and we show proof of principle that FociQuant can be used to identify changes in kinetochore protein levels in a mutant that affects kinetochore function. This analysis can be applied to any protein that forms discrete foci in cells.

AFM lithography of aluminum for fabrication of nanomechanical systems

DEFF Research Database (Denmark)

Davis, Zachary James; Abadal, G.; Hansen, Ole

2003-01-01

Nanolithography by local anodic oxidation of surfaces using atomic force microscopy (AFM) has proven to be more reproducible when using dynamic, non-contact mode. Hereby, the tip/sample interaction forces are reduced dramatically compared to contact mode, and thus tip wear is greatly reduced....... Anodic oxidation of Al can be used for fabricating nanomechanical systems, by using the Al oxide as a highly selective dry etching mask. In our experiments, areas as large as 2 mum x 3 mum have been oxidized repeatedly without any sign of tip-wear. Furthermore, line widths down to 10 nm have been...

A simple approach to quantitative analysis using three-dimensional spectra based on selected Zernike moments.

Science.gov (United States)

Zhai, Hong Lin; Zhai, Yue Yuan; Li, Pei Zhen; Tian, Yue Li

2013-01-21

A very simple approach to quantitative analysis is proposed based on the technology of digital image processing using three-dimensional (3D) spectra obtained by high-performance liquid chromatography coupled with a diode array detector (HPLC-DAD). As the region-based shape features of a grayscale image, Zernike moments with inherently invariance property were employed to establish the linear quantitative models. This approach was applied to the quantitative analysis of three compounds in mixed samples using 3D HPLC-DAD spectra, and three linear models were obtained, respectively. The correlation coefficients (R(2)) for training and test sets were more than 0.999, and the statistical parameters and strict validation supported the reliability of established models. The analytical results suggest that the Zernike moment selected by stepwise regression can be used in the quantitative analysis of target compounds. Our study provides a new idea for quantitative analysis using 3D spectra, which can be extended to the analysis of other 3D spectra obtained by different methods or instruments.

Combination of atomic force microscopy and mass spectrometry for the detection of target protein in the serum samples of children with autism spectrum disorders

Science.gov (United States)

Kaysheva, A. L.; Pleshakova, T. O.; Kopylov, A. T.; Shumov, I. D.; Iourov, I. Y.; Vorsanova, S. G.; Yurov, Y. B.; Ziborov, V. S.; Archakov, A. I.; Ivanov, Y. D.

2017-10-01

Possibility of detection of target proteins associated with development of autistic disorders in children with use of combined atomic force microscopy and mass spectrometry (AFM/MS) method is demonstrated. The proposed method is based on the combination of affine enrichment of proteins from biological samples and visualization of these proteins by AFM and MS analysis with quantitative detection of target proteins.

Ultrasonically synthesized organic liquid-filled chitosan microcapsules: part 2: characterization using AFM (atomic force microscopy) and combined AFM-confocal laser scanning fluorescence microscopy.

Science.gov (United States)

Mettu, Srinivas; Ye, Qianyu; Zhou, Meifang; Dagastine, Raymond; Ashokkumar, Muthupandian

2018-04-25

Atomic Force Microscopy (AFM) is used to measure the stiffness and Young's modulus of individual microcapsules that have a chitosan cross-linked shell encapsulating tetradecane. The oil filled microcapsules were prepared using a one pot synthesis via ultrasonic emulsification of tetradecane and crosslinking of the chitosan shell in aqueous solutions of acetic acid. The concentration of acetic acid in aqueous solutions of chitosan was varied from 0.2% to 25% v/v. The effect of acetic acid concentration and size of the individual microcapsules on the strength was probed. The deformations and forces required to rupture the microcapsules were also measured. Three dimensional deformations of microcapsules under large applied loads were obtained by the combination of Laser Scanning Confocal Microscopy (LSCM) with Atomic Force Microscopy (AFM). The stiffness, and hence the modulus, of the microcapsules was found to decrease with an increase in size with the average stiffness ranging from 82 to 111 mN m-1 and average Young's modulus ranging from 0.4 to 6.5 MPa. The forces required to rupture the microcapsules varied from 150 to 250 nN with deformations of the microcapsules up to 62 to 110% relative to their radius, respectively. Three dimensional images obtained using laser scanning confocal microscopy showed that the microcapsules retained their structure and shape after being subjected to large deformations and subsequent removal of the loads. Based on the above observations, the oil filled chitosan crosslinked microcapsules are an ideal choice for use in the food and pharmaceutical industries as they would be able to withstand the process conditions encountered.

3D investigation of dynamic behavior and sensitivity analysis of the parameters of spherical biological particles in the first phase of AFM-based manipulations with the consideration of humidity effect.

Science.gov (United States)

Korayem, M H; Mahmoodi, Z; Mohammadi, M

2018-01-07

The imaging and manipulation tools being the same in an AFM has necessitated the modeling and simulation of the AFM-based manipulation processes. In earlier studies, the dynamic behavior of biological particles in the course of manipulation has been modeled and simulated two-dimensionally. Now, with the advancements made in the modeling techniques, a 3D model of the manipulation of biological particles is more accurate than its 2D counterpart. In this paper, the effect of humidity has been taken into consideration in the three-dimensional modeling of the manipulation. By employing this model, the equations for the motion modes of particles (sliding, rolling, and spinning) at the onset of movement have been derived and the critical force magnitude has been obtained. In order to reduce the potential damage to the manipulated biological particle, the maximum radius of the tip has been determined. The effective parameters in this process have been extracted by performing sensitivity analysis using the Sobol method. In comparison to the results obtained for a dry environment, the results obtained by simulating the manipulation of a yeast particle in a wet environment shows that the critical force for the onset of particle movement diminishes by considering the moisture effect (high humidity levels). The parameters influencing the magnitude of the critical force include the particle radius, particle material, surface energy of the chosen substrate, amount of preload and the contact angle. Also, the results of the performed sensitivity analysis indicate a very high influence of particle radius on the critical manipulation force and a very low impact of cantilever width on the critical force. Copyright © 2017 Elsevier Ltd. All rights reserved.

Single particle transfer for quantitative analysis with total-reflection X-ray fluorescence spectrometry

International Nuclear Information System (INIS)

Esaka, Fumitaka; Esaka, Konomi T.; Magara, Masaaki; Sakurai, Satoshi; Usuda, Shigekazu; Watanabe, Kazuo

2006-01-01

The technique of single particle transfer was applied to quantitative analysis with total-reflection X-ray fluorescence (TXRF) spectrometry. The technique was evaluated by performing quantitative analysis of individual Cu particles with diameters between 3.9 and 13.2 μm. The direct quantitative analysis of the Cu particle transferred onto a Si carrier gave a discrepancy between measured and calculated Cu amounts due to the absorption effects of incident and fluorescent X-rays within the particle. By the correction for the absorption effects, the Cu amounts in individual particles could be determined with the deviation within 10.5%. When the Cu particles were dissolved with HNO 3 solution prior to the TXRF analysis, the deviation was improved to be within 3.8%. In this case, no correction for the absorption effects was needed for quantification

Force Spectroscopy of Hyaluronan by AFM; From H-bonded Networks Towards Single Chain Behavior

NARCIS (Netherlands)

Giannotti, M.I.; Rinaudo, Marguerite; Vancso, Gyula J.

2007-01-01

The conformational behavior of hyaluronan (HA) polysaccharide chains in aqueous NaCl solution was characterized directly at the single-molecule level. This comunication reports on one of the first single-chain atomic force microscopy (AFM) experiments performed at variable temperatures,

Quantitative analysis of thallium-201 myocardial scintigraphy

International Nuclear Information System (INIS)

Kanemoto, Nariaki; Hoer, G.; Johost, S.; Maul, F.-D.; Standke, R.

1981-01-01

The method of quantitative analysis of thallium-201 myocardial scintigraphy using computer assisted technique was described. Calculated indices are washout factor, vitality index and redistribution factor. Washout factor is the ratio of counts at certain period of time after exercise and immediately after exercise. This value is neccessary for the evaluation of redistribution to the ischemic areas in serial imagings to correct the Tl-201 washout from the myocardium under the assumption that the washout is constant in the whole myocardium. Vitality index is the ratio between the Tl-201 uptake in the region of interest and that of the maximum. Redistribution factor is the ratio of the redistribution in the region of interest in serial imagings after exercise to that of immediately after exercise. Four examples of exercise Tl-201 myocardial scintigrams and the quantitative analyses before and after the percutaneous transluminal coronary angioplasty were presented. (author)

Capillary force on a tilted cylinder: Atomic Force Microscope (AFM) measurements.

Science.gov (United States)

Kosgodagan Acharige, Sébastien; Laurent, Justine; Steinberger, Audrey

2017-11-01

The capillary force in situations where the liquid meniscus is asymmetric, such as the one around a tilted object, has been hitherto barely investigated even though these situations are very common in practice. In particular, the capillary force exerted on a tilted object may depend on the dipping angle i. We investigate experimentally the capillary force that applies on a tilted cylinder as a function of its dipping angle i, using a home-built tilting Atomic Force Microscope (AFM) with custom made probes. A micrometric-size rod is glued at the end of an AFM cantilever of known stiffness, whose deflection is measured when the cylindrical probe is dipped in and retracted from reference liquids. We show that a torque correction is necessary to understand the measured deflection. We give the explicit expression of this correction as a function of the probes' geometrical parameters, so that its magnitude can be readily evaluated. The results are compatible with a vertical capillary force varying as 1/cosi, in agreement with a recent theoretical prediction. Finally, we discuss the accuracy of the method for measuring the surface tension times the cosine of the contact angle of the liquid on the probe. Copyright © 2017 Elsevier Inc. All rights reserved.

Probing of miniPEGγ-PNA-DNA Hybrid Duplex Stability with AFM Force Spectroscopy.

Science.gov (United States)

Dutta, Samrat; Armitage, Bruce A; Lyubchenko, Yuri L

2016-03-15

Peptide nucleic acids (PNA) are synthetic polymers, the neutral peptide backbone of which provides elevated stability to PNA-PNA and PNA-DNA hybrid duplexes. It was demonstrated that incorporation of diethylene glycol (miniPEG) at the γ position of the peptide backbone increased the thermal stability of the hybrid duplexes (Sahu, B. et al. J. Org. Chem. 2011, 76, 5614-5627). Here, we applied atomic force microscopy (AFM) based single molecule force spectroscopy and dynamic force spectroscopy (DFS) to test the strength and stability of the hybrid 10 bp duplex. This hybrid duplex consisted of miniPEGγ-PNA and DNA of the same length (γ(MP)PNA-DNA), which we compared to a DNA duplex with a homologous sequence. AFM force spectroscopy data obtained at the same conditions showed that the γ(MP)PNA-DNA hybrid is more stable than the DNA counterpart, 65 ± 15 pN vs 47 ± 15 pN, respectively. The DFS measurements performed in a range of pulling speeds analyzed in the framework of the Bell-Evans approach yielded a dissociation constant, koff ≈ 0.030 ± 0.01 s⁻¹ for γ(MP)PNA-DNA hybrid duplex vs 0.375 ± 0.18 s⁻¹ for the DNA-DNA duplex suggesting that the hybrid duplex is much more stable. Correlating the high affinity of γ(MP)PNA-DNA to slow dissociation kinetics is consistent with prior bulk characterization by surface plasmon resonance. Given the growing interest in γ(MP)PNA as well as other synthetic DNA analogues, the use of single molecule experiments along with computational analysis of force spectroscopy data will provide direct characterization of various modifications as well as higher order structures such as triplexes and quadruplexes.

AFM characterization of protein net formation on a fibrous medium

Directory of Open Access Journals (Sweden)

Assis O.B.G.

2000-01-01

Full Text Available Lysozyme protein net is set on a glass fiber support using the self-assembly technique. Enzymatic film formation is followed by surface imaging via atomic force microscopy (AFM. Change in roughness as a function of deposition time is used as an indirect indicator of film formation. The objective was to form a protein film that would have no effect on the permeability of the medium, aiming at its application as a bioactive membrane or reactor suitable for bacteria and chemical interactions in aqueous media.

In-situ investigation of adsorption of dye and coadsorbates on TiO 2 films using QCM-D, fluorescence and AFM techniques

KAUST Repository

Harms, Hauke A.

2013-09-11

Simultaneous adsorption of dye molecules and coadsorbates is important for the fabrication of high-efficiency dyesensitized solar cells, but its mechanism is not well understood. Herein, we use a quartz crystal microbalance with dissipation technique (QCM-D) to study dynamically and quantitatively the sensitization of TiO2 in situ. We investigate dye loading for a ruthenium(II) polypyridyl complex (Z907), of a triphenylamine-based D-π-A dye (Y123), and of a ullazine sensitizer (JD21), as well as the simultaneous adsorption of the latter two with the coadsorbate chenodeoxycholic acid. By combining the QCM-D technique with fluorescence measurements, we quantify molar ratios between the dye and coadsorbate. Furthermore, we will present first studies using liquid-phase AFM on the adsorbed dye monolayer, thus obtaining complementary microscopic information that may lead to understanding of the adsorption mechanism on the molecular scale. © 2013 SPIE.

Investigation of lateral forces in dynamic mode using combined AFM/STM

OpenAIRE

Atabak, Mehrdad

2007-01-01

Ankara : The Department of Physics and The Institute of Engineering and Science of Bilkent University, 2007. Thesis (Ph.D.) -- Bilkent University, 2007. Includes bibliographical references leaves 114-126. In this Ph.D. work, we constructed a ¯ber optic interferometer based non-contact Atomic Force Microscope (nc-AFM) combined with Scanning Tunneling Micro- scope(STM) to study lateral force interactions on Si(111)-(77) surface. The in- terferometer has been built in such a wa...

Tuning adhesion forces between functionalized gold colloidal nanoparticles and silicon AFM tips: role of ligands and capillary forces.

Science.gov (United States)

Oras, Sven; Vlassov, Sergei; Berholts, Marta; Lõhmus, Rünno; Mougin, Karine

2018-01-01

Adhesion forces between functionalized gold colloidal nanoparticles (Au NPs) and scanning probe microscope silicon tips were experimentally investigated by atomic force microscopy (AFM) equipped with PeakForce QNM (Quantitative Nanoscale Mechanics) module. Au NPs were synthesized by a seed-mediated process and then functionalized with thiols containing different functional groups: amino, hydroxy, methoxy, carboxy, methyl, and thiol. Adhesion measurements showed strong differences between NPs and silicon tip depending on the nature of the tail functional group. The dependence of the adhesion on ligand density for different thiols with identical functional tail-group was also demonstrated. The calculated contribution of the van der Waals (vdW) forces between particles was in good agreement with experimentally measured adhesive values. In addition, the adhesion forces were evaluated between flat Au films functionalized with the same molecular components and silicon tips to exclude the effect of particle shape on the adhesion values. Although adhesion values on flat substrates were higher than on their nanoparticle counterparts, the dependance on functional groups remained the same.

Quantitative pulsed eddy current analysis

International Nuclear Information System (INIS)

Morris, R.A.

1975-01-01

The potential of pulsed eddy current testing for furnishing more information than conventional single-frequency eddy current methods has been known for some time. However, a fundamental problem has been analyzing the pulse shape with sufficient precision to produce accurate quantitative results. Accordingly, the primary goal of this investigation was to: demonstrate ways of digitizing the short pulses encountered in PEC testing, and to develop empirical analysis techniques that would predict some of the parameters (e.g., depth) of simple types of defect. This report describes a digitizing technique using a computer and either a conventional nuclear ADC or a fast transient analyzer; the computer software used to collect and analyze pulses; and some of the results obtained. (U.S.)

Quantitative surface analysis using deuteron-induced nuclear reactions

International Nuclear Information System (INIS)

Afarideh, Hossein

1991-01-01

The nuclear reaction analysis (NRA) technique consists of looking at the energies of the reaction products which uniquely define the particular elements present in the sample and it analysis the yield/energy distribution to reveal depth profiles. A summary of the basic features of the nuclear reaction analysis technique is given, in particular emphasis is placed on quantitative light element determination using (d,p) and (d,alpha) reactions. The experimental apparatus is also described. Finally a set of (d,p) spectra for the elements Z=3 to Z=17 using 2 MeV incident deutrons is included together with example of more applications of the (d,alpha) spectra. (author)

Evaluation of shear wave elastography for differential diagnosis of breast lesions: A new qualitative analysis versus conventional quantitative analysis.

Science.gov (United States)

Ren, Wei-Wei; Li, Xiao-Long; Wang, Dan; Liu, Bo-Ji; Zhao, Chong-Ke; Xu, Hui-Xiong

2018-04-13

To evaluate a special kind of ultrasound (US) shear wave elastography for differential diagnosis of breast lesions, using a new qualitative analysis (i.e. the elasticity score in the travel time map) compared with conventional quantitative analysis. From June 2014 to July 2015, 266 pathologically proven breast lesions were enrolled in this study. The maximum, mean, median, minimum, and standard deviation of shear wave speed (SWS) values (m/s) were assessed. The elasticity score, a new qualitative feature, was evaluated in the travel time map. The area under the receiver operating characteristic (AUROC) curves were plotted to evaluate the diagnostic performance of both qualitative and quantitative analyses for differentiation of breast lesions. Among all quantitative parameters, SWS-max showed the highest AUROC (0.805; 95% CI: 0.752, 0.851) compared with SWS-mean (0.786; 95% CI:0.732, 0.834; P = 0.094), SWS-median (0.775; 95% CI:0.720, 0.824; P = 0.046), SWS-min (0.675; 95% CI:0.615, 0.731; P = 0.000), and SWS-SD (0.768; 95% CI:0.712, 0.817; P = 0.074). The AUROC of qualitative analysis in this study obtained the best diagnostic performance (0.871; 95% CI: 0.825, 0.909, compared with the best parameter of SWS-max in quantitative analysis, P = 0.011). The new qualitative analysis of shear wave travel time showed the superior diagnostic performance in the differentiation of breast lesions in comparison with conventional quantitative analysis.

Effect of TMAH Etching Duration on the Formation of Silicon Nano wire Transistor Patterned by AFM Nano lithography

International Nuclear Information System (INIS)

Hutagalung, S.D.; Lew, K.C.

2012-01-01

Atomic force microscopy (AFM) lithography was applied to produce nano scale pattern for silicon nano wire transistor fabrication. This technique takes advantage of imaging facility of AFM and the ability of probe movement controlling over the sample surface to create nano patterns. A conductive AFM tip was used to grow the silicon oxide nano patterns on silicon on insulator (SOI) wafer. The applied tip-sample voltage and writing speed were well controlled in order to form pre-designed silicon oxide nano wire transistor structures. The effect of tetra methyl ammonium hydroxide (TMAH) etching duration on the oxide covered silicon nano wire transistor structure has been investigated. A completed silicon nano wire transistor was obtained by removing the oxide layer via hydrofluoric acid etching process. The fabricated silicon nano wire transistor consists of a silicon nano wire that acts as a channel with source and drain pads. A lateral gate pad with a nano wire head was fabricated very close to the channel in the formation of transistor structures. (author)

MCM - 2 and Ki - 67 as proliferation markers in renal cell carcinoma: A quantitative and semi - quantitative analysis.

Science.gov (United States)

Mehdi, Muhammad Zain; Nagi, Abdul Hanan; Naseem, Nadia

2016-01-01

Fuhrman nuclear grade is the most important histological parameter to predict prognosis in a patient of renal cell carcinoma (RCC). However, it suffers from inter-observer and intra-observer variation giving rise to need of a parameter that not only correlates with nuclear grade but is also objective and reproducible. Proliferation is the measure of aggressiveness of a tumour and it is strongly correlated with Fuhrman nuclear grade, clinical survival and recurrence in RCC. Ki-67 is conventionally used to assess proliferation. Mini-chromosome maintenance 2 (MCM-2) is a lesser known marker of proliferation and identifies a greater proliferation faction. This study was designed to assess the prognostic significance of MCM-2 by comparing it with Fuhrman nuclear grade and Ki-67. n=50 cases of various ages, stages, histological subtypes and grades of RCC were selected for this study. Immunohistochemical staining using Ki-67(MIB-1, Mouse monoclonal antibody, Dako) and MCM-2 (Mouse monoclonal antibody, Thermo) was performed on the paraffin embedded blocks in the department of Morbid anatomy and Histopathology, University of Health Sciences, Lahore. Labeling indices (LI) were determined by two pathologists independently using quantitative and semi-quantitative analysis. Statistical analysis was carried out using SPSS 20.0. Kruskall-Wallis test was used to determine a correlation of proliferation markers with grade, and Pearson's correlate was used to determine correlation between the two proliferation markers. Labeling index of MCM-2 (median=24.29%) was found to be much higher than Ki-67(median=13.05%). Both markers were significantly related with grade (p=0.00; Kruskall-Wallis test). LI of MCM-2 was found to correlate significantly with LI of Ki-67(r=0.0934;p=0.01 with Pearson's correlate). Results of semi-quantitative analysis correlated well with quantitative analysis. Both Ki-67 and MCM-2 are markers of proliferation which are closely linked to grade. Therefore, they

Quantitative Myocardial Perfusion Imaging Versus Visual Analysis in Diagnosing Myocardial Ischemia: A CE-MARC Substudy.

Science.gov (United States)

Biglands, John D; Ibraheem, Montasir; Magee, Derek R; Radjenovic, Aleksandra; Plein, Sven; Greenwood, John P

2018-05-01

This study sought to compare the diagnostic accuracy of visual and quantitative analyses of myocardial perfusion cardiovascular magnetic resonance against a reference standard of quantitative coronary angiography. Visual analysis of perfusion cardiovascular magnetic resonance studies for assessing myocardial perfusion has been shown to have high diagnostic accuracy for coronary artery disease. However, only a few small studies have assessed the diagnostic accuracy of quantitative myocardial perfusion. This retrospective study included 128 patients randomly selected from the CE-MARC (Clinical Evaluation of Magnetic Resonance Imaging in Coronary Heart Disease) study population such that the distribution of risk factors and disease status was proportionate to the full population. Visual analysis results of cardiovascular magnetic resonance perfusion images, by consensus of 2 expert readers, were taken from the original study reports. Quantitative myocardial blood flow estimates were obtained using Fermi-constrained deconvolution. The reference standard for myocardial ischemia was a quantitative coronary x-ray angiogram stenosis severity of ≥70% diameter in any coronary artery of >2 mm diameter, or ≥50% in the left main stem. Diagnostic performance was calculated using receiver-operating characteristic curve analysis. The area under the curve for visual analysis was 0.88 (95% confidence interval: 0.81 to 0.95) with a sensitivity of 81.0% (95% confidence interval: 69.1% to 92.8%) and specificity of 86.0% (95% confidence interval: 78.7% to 93.4%). For quantitative stress myocardial blood flow the area under the curve was 0.89 (95% confidence interval: 0.83 to 0.96) with a sensitivity of 87.5% (95% confidence interval: 77.3% to 97.7%) and specificity of 84.5% (95% confidence interval: 76.8% to 92.3%). There was no statistically significant difference between the diagnostic performance of quantitative and visual analyses (p = 0.72). Incorporating rest myocardial

Cell visco-elasticity measured with AFM and optical trapping at sub-micrometer deformations.

Directory of Open Access Journals (Sweden)

Schanila Nawaz

Full Text Available The measurement of the elastic properties of cells is widely used as an indicator for cellular changes during differentiation, upon drug treatment, or resulting from the interaction with the supporting matrix. Elasticity is routinely quantified by indenting the cell with a probe of an AFM while applying nano-Newton forces. Because the resulting deformations are in the micrometer range, the measurements will be affected by the finite thickness of the cell, viscous effects and even cell damage induced by the experiment itself. Here, we have analyzed the response of single 3T3 fibroblasts that were indented with a micrometer-sized bead attached to an AFM cantilever at forces from 30-600 pN, resulting in indentations ranging from 0.2 to 1.2 micrometer. To investigate the cellular response at lower forces up to 10 pN, we developed an optical trap to indent the cell in vertical direction, normal to the plane of the coverslip. Deformations of up to two hundred nanometers achieved at forces of up to 30 pN showed a reversible, thus truly elastic response that was independent on the rate of deformation. We found that at such small deformations, the elastic modulus of 100 Pa is largely determined by the presence of the actin cortex. At higher indentations, viscous effects led to an increase of the apparent elastic modulus. This viscous contribution that followed a weak power law, increased at larger cell indentations. Both AFM and optical trapping indentation experiments give consistent results for the cell elasticity. Optical trapping has the benefit of a lower force noise, which allows a more accurate determination of the absolute indentation. The combination of both techniques allows the investigation of single cells at small and large indentations and enables the separation of their viscous and elastic components.

A critical appraisal of semi-quantitative analysis of 2-deoxyglucose autoradiograms

International Nuclear Information System (INIS)

Kelly, P.T.; McCulloch, J.

1983-01-01

Semi-quantitative analysis (e.g. optical density ratios) of [ 14 C]2-deoxyglucose autoradiograms is widely used in neuroscience research. The authors demonstrate that a fixed ratio of 14 C-concentrations in the CNS does not yield a constant optical density ratio but is dependent upon the exposure time in the preparation of the autoradiograms and the absolute amounts of 14 C from which the concentration ratio is derived. The failure of a fixed glucose utilization ratio to result in a constant optical density ratio represents a major interpretative difficulty in investigations where only semi-quantitative analysis of [ 14 C]2-deoxyglucose autoradiograms is undertaken. (Auth.)

Quantitative analysis of culture using millions of digitized books.

Science.gov (United States)

Michel, Jean-Baptiste; Shen, Yuan Kui; Aiden, Aviva Presser; Veres, Adrian; Gray, Matthew K; Pickett, Joseph P; Hoiberg, Dale; Clancy, Dan; Norvig, Peter; Orwant, Jon; Pinker, Steven; Nowak, Martin A; Aiden, Erez Lieberman

2011-01-14

We constructed a corpus of digitized texts containing about 4% of all books ever printed. Analysis of this corpus enables us to investigate cultural trends quantitatively. We survey the vast terrain of 'culturomics,' focusing on linguistic and cultural phenomena that were reflected in the English language between 1800 and 2000. We show how this approach can provide insights about fields as diverse as lexicography, the evolution of grammar, collective memory, the adoption of technology, the pursuit of fame, censorship, and historical epidemiology. Culturomics extends the boundaries of rigorous quantitative inquiry to a wide array of new phenomena spanning the social sciences and the humanities.

Quantitative analysis of culture using millions of digitized books

Science.gov (United States)

Michel, Jean-Baptiste; Shen, Yuan Kui; Aiden, Aviva P.; Veres, Adrian; Gray, Matthew K.; Pickett, Joseph P.; Hoiberg, Dale; Clancy, Dan; Norvig, Peter; Orwant, Jon; Pinker, Steven; Nowak, Martin A.; Aiden, Erez Lieberman

2011-01-01

We constructed a corpus of digitized texts containing about 4% of all books ever printed. Analysis of this corpus enables us to investigate cultural trends quantitatively. We survey the vast terrain of ‘culturomics’, focusing on linguistic and cultural phenomena that were reflected in the English language between 1800 and 2000. We show how this approach can provide insights about fields as diverse as lexicography, the evolution of grammar, collective memory, the adoption of technology, the pursuit of fame, censorship, and historical epidemiology. ‘Culturomics’ extends the boundaries of rigorous quantitative inquiry to a wide array of new phenomena spanning the social sciences and the humanities. PMID:21163965

Quantitative mass spectrometric analysis of glycoproteins combined with enrichment methods.

Science.gov (United States)

Ahn, Yeong Hee; Kim, Jin Young; Yoo, Jong Shin

2015-01-01

Mass spectrometry (MS) has been a core technology for high sensitive and high-throughput analysis of the enriched glycoproteome in aspects of quantitative assays as well as qualitative profiling of glycoproteins. Because it has been widely recognized that aberrant glycosylation in a glycoprotein may involve in progression of a certain disease, the development of efficient analysis tool for the aberrant glycoproteins is very important for deep understanding about pathological function of the glycoprotein and new biomarker development. This review first describes the protein glycosylation-targeting enrichment technologies mainly employing solid-phase extraction methods such as hydrizide-capturing, lectin-specific capturing, and affinity separation techniques based on porous graphitized carbon, hydrophilic interaction chromatography, or immobilized boronic acid. Second, MS-based quantitative analysis strategies coupled with the protein glycosylation-targeting enrichment technologies, by using a label-free MS, stable isotope-labeling, or targeted multiple reaction monitoring (MRM) MS, are summarized with recent published studies. © 2014 The Authors. Mass Spectrometry Reviews Published by Wiley Periodicals, Inc.

Tribological behavior of micro/nano-patterned surfaces in contact with AFM colloidal probe

International Nuclear Information System (INIS)

Zhang Xiaoliang; Wang Xiu; Kong Wen; Yi Gewen; Jia Junhong

2011-01-01

In effort to investigate the influence of the micro/nano-patterning or surface texturing on the nanotribological properties of patterned surfaces, the patterned polydimethylsiloxane (PDMS) surfaces with pillars were fabricated by replica molding technique. The surface morphologies of patterned PDMS surfaces with varying pillar sizes and spacing between pillars were characterized by atomic force microscope (AFM) and scanning electron microscope (SEM). The AFM/FFM was used to acquire the friction force images of micro/nano-patterned surfaces using a colloidal probe. A difference in friction force produced a contrast on the friction force images when the colloidal probe slid over different regions of the patterned polymer surfaces. The average friction force of patterned surface was related to the spacing between the pillars and their size. It decreased with the decreasing of spacing between the pillars and the increasing of pillar size. A reduction in friction force was attributed to the reduced area of contact between patterned surface and colloidal probe. Additionally, the average friction force increased with increasing applied load and sliding velocity.

Tribological behavior of micro/nano-patterned surfaces in contact with AFM colloidal probe

Energy Technology Data Exchange (ETDEWEB)

Zhang Xiaoliang; Wang Xiu; Kong Wen [State Key Laboratory of Solid Lubrication, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou 730000 (China); Graduate University of Chinese Academy of Sciences, Beijing 100049 (China); Yi Gewen [State Key Laboratory of Solid Lubrication, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou 730000 (China); Jia Junhong, E-mail: jhjia@licp.cas.cn [State Key Laboratory of Solid Lubrication, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou 730000 (China)

2011-10-15

In effort to investigate the influence of the micro/nano-patterning or surface texturing on the nanotribological properties of patterned surfaces, the patterned polydimethylsiloxane (PDMS) surfaces with pillars were fabricated by replica molding technique. The surface morphologies of patterned PDMS surfaces with varying pillar sizes and spacing between pillars were characterized by atomic force microscope (AFM) and scanning electron microscope (SEM). The AFM/FFM was used to acquire the friction force images of micro/nano-patterned surfaces using a colloidal probe. A difference in friction force produced a contrast on the friction force images when the colloidal probe slid over different regions of the patterned polymer surfaces. The average friction force of patterned surface was related to the spacing between the pillars and their size. It decreased with the decreasing of spacing between the pillars and the increasing of pillar size. A reduction in friction force was attributed to the reduced area of contact between patterned surface and colloidal probe. Additionally, the average friction force increased with increasing applied load and sliding velocity.

Characterization of opto-electrical enhancement of tandem photoelectrochemical cells by using photoconductive-AFM

Science.gov (United States)

Park, Sun-Young; Elbersen, Rick; Huskens, Jurriaan; Gardeniers, Han; Lee, Joo-Yul; Mul, Guido; Heo, Jinhee

2017-07-01

Solar-to-hydrogen conversion by water splitting in photoelectrochemical cells (PECs) is a promising approach to alleviate problems associated with intermittency in solar energy supply and demand. Several interfacial resistances in photoelectrodes limit the performance of such cells, while the properties of interfaces are not easy to analyze in situ. We applied photoconductive-AFM to analyze the performance of WO3/p+n Si photoanodes, containing an ultra-thin metal interface of either Au or Pt. The Au interface consisted of Au nanoparticles with well-ordered interspacing, while Pt was present in the form of a continuous film. Photoconductive-AFM data show that upon illumination significantly larger currents are measured for the WO3/p+n Si anode equipped with the Au interface, as compared to the WO3/p+n Si anode with the Pt interface, in agreement with the better performance of the former electrode in a photoelectrochemical cell. The remarkable performance of the Au-containing electrode is proposed to be the result of favorable electron-hole recombination rates induced by the Au nanoparticles in a plasmon resonance excited state.

Sensing inhomogeneous mechanical properties of human corneal Descemet's membrane with AFM nano-indentation.

Science.gov (United States)

Di Mundo, Rosa; Recchia, Giuseppina; Parekh, Mohit; Ruzza, Alessandro; Ferrari, Stefano; Carbone, Giuseppe

2017-10-01

The paper describes a highly space-resolved characterization of the surface mechanical properties of the posterior human corneal layer (Descemet's membrane). This has been accomplished with Atomic Force Microscopy (AFM) nano-indentation by using a probe with a sharp tip geometry. Results indicate that the contact with this biological tissue in liquid occurs with no (or very low) adhesion. More importantly, under the same operating conditions, a broad distribution of penetration depth can be measured on different x-y positions of the tissue surface, indicating a high inhomogeneity of surface stiffness, not yet clearly reported in the literature. An important contribution to such inhomogeneity should be ascribed to the discontinuous nature of the collagen/proteoglycans fibers matrix tissue, as can be imaged by AFM when the tissue is semi-dry. Using classical contact mechanics calculations adapted to the specific geometry of the tetrahedral tip it has been found that the elastic modulus E of the material in the very proximity of the surface ranges from 0.23 to 2.6 kPa. Copyright © 2017 Elsevier Ltd. All rights reserved.

Quantitative analysis of macro-ARG using IP system

International Nuclear Information System (INIS)

Nakajima, Eiichi; Kawai, Kenji; Furuta, Yoshitake

1997-01-01

Recent progress in imaging plate (IP) system allow us to analyze autoradiographic images quantitatively. In the 'whole-body autoradiography', a method clarify the distribution of radioisotope or labeled compounds in the tissues and organs in a freeze-dried whole-body section of small animals such as rats and mice, the sections are pressed against a IP for exposure and the IP is scanned by Bio-Imaging Analyzer (Fuji Photo Film Co., Ltd) and a digital autoradiographic image is given. Quantitative data concerning the activity in different tissues can be obtained using an isotope scale as a reference source. Fading effect, application of IP system for distribution of receptor binding ARG, analysis of radio-spots on TLC and radioactive concentration in liquid such as blood are also discussed. (author)

Potential Application of Quantitative Prostate-specific Antigen Analysis in Forensic Examination of Seminal Stains

Directory of Open Access Journals (Sweden)

Zhenping Liu

2015-01-01

Full Text Available The aims of this study are to use quantitative analysis of the prostate-specific antigen (PSA in the seminal stain examination and to explore the practical value of this analysis in forensic science. For a comprehensive analysis, vaginal swabs from 48 rape cases were tested both by a PSA fluorescence analyzer (i-CHROMA Reader and by a conventional PSA strip test. To confirm the results of these PSA tests, seminal DNA was tested following differential extraction. Compared to the PSA strip test, the PSA rapid quantitative fluorescence analyzer provided the more accurate and sensitive results. More importantly, individualized schemes based on quantitative PSA results of samples can be developed to improve the quality and procedural efficiency in the forensic seminal inspection of samples prior to DNA analysis.

On the Need for Quantitative Bias Analysis in the Peer-Review Process.

Science.gov (United States)

Fox, Matthew P; Lash, Timothy L

2017-05-15

Peer review is central to the process through which epidemiologists generate evidence to inform public health and medical interventions. Reviewers thereby act as critical gatekeepers to high-quality research. They are asked to carefully consider the validity of the proposed work or research findings by paying careful attention to the methodology and critiquing the importance of the insight gained. However, although many have noted problems with the peer-review system for both manuscripts and grant submissions, few solutions have been proposed to improve the process. Quantitative bias analysis encompasses all methods used to quantify the impact of systematic error on estimates of effect in epidemiologic research. Reviewers who insist that quantitative bias analysis be incorporated into the design, conduct, presentation, and interpretation of epidemiologic research could substantially strengthen the process. In the present commentary, we demonstrate how quantitative bias analysis can be used by investigators and authors, reviewers, funding agencies, and editors. By utilizing quantitative bias analysis in the peer-review process, editors can potentially avoid unnecessary rejections, identify key areas for improvement, and improve discussion sections by shifting from speculation on the impact of sources of error to quantification of the impact those sources of bias may have had. © The Author 2017. Published by Oxford University Press on behalf of the Johns Hopkins Bloomberg School of Public Health. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Characteristics of fracture during the approach process and wear mechanism of a silicon AFM tip

International Nuclear Information System (INIS)

Chung, Koo-Hyun; Lee, Yong-Ha; Kim, Dae-Eun

2005-01-01

The wear of an atomic force microscope (AFM) tip is one of the crucial issues in AFM as well as in other probe-based applications. In this work, wear tests under extremely low normal load using an AFM were conducted. Also, in order to understand the nature of silicon tip wear, the wear characteristics of crystal silicon and amorphous silicon oxide layer were investigated by a high-resolution transmission electron microscope (HRTEM). It was found that fracture of the tip readily occurred due to impact during the approach process. Experimental results showed that the impact should be below 0.1 nN s to avoid significant fracture of the tip. Also, it was observed that wear of the amorphous layer, formed at the end of the tip, occurred at the initial stage of the silicon tip damage process. Based on Archard's wear law, the wear coefficient of the amorphous layer was in the range of 0.009-0.014. As for the wear characteristics of the silicon tip, it was shown that wear occurred gradually under light normal load and the wear rate decreased with increase in the sliding distance. As for the wear mechanism of the silicon tip, oxidation wear was identified to be the most significant. It was shown that the degree of oxidation was higher under high normal load and in a nitrogen environment, oxidation of the silicon tip was reduced

A new approach of recognition of ellipsoidal micro- and nanoparticles on AFM images and determination of their sizes

International Nuclear Information System (INIS)

Akhmadeev, Albert A; Kh Salakhov, Myakzyum

2016-01-01

In this work we develop an approach of automatic recognition of ellipsoidal particles on the atomic force microscopy (AFM) image and determination of their size, which is based on image segmentation and the surface approximation by ellipsoids. In addition to the comparative simplicity and rapidity of processing, this method allows us to determine the size of particles, the surface of which is not completely visible on the image. The proposed method showed good results on simulated images including noisy ones. Using this algorithm the size distributions of silica particles on experimental AFM images have been determined. (paper)

Immune adherence: a quantitative and kinetic analysis

Energy Technology Data Exchange (ETDEWEB)

Sekine, T [National Cancer Center, Tokyo (Japan). Research Inst.

1978-09-01

Quantitative and kinetic analysis of the immune-adherence reaction (IA) between C3b fragments and IA receptors as an agglutination reaction is difficult. Analysis is possible, however, by use of radio-iodinated bovine serum albumin as antigen at low concentrations (less than 200 ng/ml) and optimal concentration of antibody to avoid precipitation of antigen-antibody complexes with human erythrocytes without participation of complement. Antigen and antibody are reacted at 37/sup 0/C, complement is added, the mixture incubated and human erythrocytes added; after further incubation, ice-cold EDTA containing buffer is added and the erythrocytes centrifuged and assayed for radioactivity. Control cells reacted with heated guinea pig serum retained less than 5% of the added radioactivity. The method facilitates measurement of IA reactivity and permits more detailed analysis of the mechanism underlying the reaction.

Thermally-treated Pt-coated silicon AFM tips for wear resistance in ferroelectric data storage

International Nuclear Information System (INIS)

Bhushan, Bharat; Palacio, Manuel; Kwak, Kwang Joo

2008-01-01

In ferroelectric data storage, a conductive atomic force microscopy (AFM) probe with a noble metal coating is placed in contact with a lead zirconate titanate (PZT) film. The understanding and improvement of probe tip wear, particularly at high velocities, is needed for high data rate recording. A commercial Pt-coated silicon AFM probe was thermally treated in order to form platinum silicide at the near-surface. Nanoindentation, nanoscratch and wear experiments were performed to evaluate the mechanical properties and wear performance at high velocities. The thermally treated tip exhibited lower wear than the untreated tip. The tip wear mechanism is adhesive and abrasive wear with some evidence of impact wear. The enhancement in mechanical properties and wear resistance in the thermally treated film is attributed to silicide formation in the near-surface. Auger electron spectroscopy and electrical resistivity measurements confirm the formation of platinum silicide. This study advances the understanding of thin film nanoscale surface interactions

The use of functionalized AFM tips as molecular sensors in the detection of pesticides

International Nuclear Information System (INIS)

Deda, Daiana K.; Pereira, Barbara B.S.; Bueno, Carolina C.; Silva, Aline N. da; Ribeiro, Gabrielle A.; Amarante, Adriano M.; Leite, Fabio L.; Franca, Eduardo F.

2013-01-01

Atomic force spectroscopy, a technique derived from Atomic Force Microscopy (AFM), allowed to distinguish nonspecific and specific interactions between the acetolactate synthase enzyme (ALS) and anti-atrazine antibody biomolecules and the herbicides imazaquin, metsulfuron-methyl and atrazine. The presence of specific interactions increased the adhesion force (F adh ) between the AFM tip and the herbicides, which made the modified tip a powerful biosensor. Increases of approximately 132% and 145% in the F adh values were observed when a tip functionalized with ALS was used to detect imazaquin and metsulfuron-methyl, respectively. The presence of specific interactions between the atrazine and the anti-atrazine antibody also caused an increase in the F adh values (approximately 175%) compared to those observed when using an unfunctionalized tip. The molecular modeling results obtained with the ALS enzyme suggest that the orientation of the biomolecule on the tip surface could be suitable for allowing interaction with the herbicides imazaquin and metsulfuron-methyl. (author)

The use of functionalized AFM tips as molecular sensors in the detection of pesticides

Directory of Open Access Journals (Sweden)

Daiana K. Deda

2013-06-01

Full Text Available Atomic force spectroscopy, a technique derived from Atomic Force Microscopy (AFM, allowed us to distinguish nonspecific and specific interactions between the acetolactate synthase enzyme (ALS and anti-atrazine antibody biomolecules and the herbicides imazaquin, metsulfuron-methyl and atrazine. The presence of specific interactions increased the adhesion force (Fadh between the AFM tip and the herbicides, which made the modified tip a powerful biosensor. Increases of approximately 132% and 145% in the Fadh values were observed when a tip functionalized with ALS was used to detect imazaquin and metsulfuron-methyl, respectively. The presence of specific interactions between the atrazine and the anti-atrazine antibody also caused an increase in the Fadh values (approximately 175% compared to those observed when using an unfunctionalized tip. The molecular modeling results obtained with the ALS enzyme suggest that the orientation of the biomolecule on the tip surface could be suitable for allowing interaction with the herbicides imazaquin and metsulfuron-methyl.

The use of functionalized AFM tips as molecular sensors in the detection of pesticides

Energy Technology Data Exchange (ETDEWEB)

Deda, Daiana K.; Pereira, Barbara B.S.; Bueno, Carolina C.; Silva, Aline N. da; Ribeiro, Gabrielle A.; Amarante, Adriano M.; Leite, Fabio L., E-mail: fabioleite@ufscar.br [Universidade Federal de Sao Carlos (LNN/UFSCar), Sorocaba, SP (Brazil). Dept. de Fisica, Quimica e Matematica. Lab. de Nanoneurobiofisica; Franca, Eduardo F. [Universidade Federal de Uberlandia (UFU), MG (Brazil). Inst. de Quimica

2013-11-01

Atomic force spectroscopy, a technique derived from Atomic Force Microscopy (AFM), allowed to distinguish nonspecific and specific interactions between the acetolactate synthase enzyme (ALS) and anti-atrazine antibody biomolecules and the herbicides imazaquin, metsulfuron-methyl and atrazine. The presence of specific interactions increased the adhesion force (F{sub adh}) between the AFM tip and the herbicides, which made the modified tip a powerful biosensor. Increases of approximately 132% and 145% in the F{sub adh} values were observed when a tip functionalized with ALS was used to detect imazaquin and metsulfuron-methyl, respectively. The presence of specific interactions between the atrazine and the anti-atrazine antibody also caused an increase in the F{sub adh} values (approximately 175%) compared to those observed when using an unfunctionalized tip. The molecular modeling results obtained with the ALS enzyme suggest that the orientation of the biomolecule on the tip surface could be suitable for allowing interaction with the herbicides imazaquin and metsulfuron-methyl. (author)

AFM studies of environmental effects on nanomechanical properties and cellular structure of human hair

International Nuclear Information System (INIS)

Bhushan, Bharat; Chen, Nianhuan

2006-01-01

Characterization of cellular structure and physical and mechanical properties of hair are essential to develop better cosmetic products and advance biological and cosmetic science. Although the morphology of the cellular structure of human hair has been traditionally investigated using scanning electron microscopy and transmission electron microscopy, these techniques provide limited capability to in situ study of the physical and mechanical properties of human hair in various environments. Atomic force microscopy (AFM) overcomes these problems and can be used for characterization in ambient conditions without requiring specific sample preparations and surface treatment. In this study, film thickness, adhesive forces and effective Young's modulus of various hair surfaces were measured at different environments (humidity and temperature) using force calibration plot technique with an AFM. Torsional resonance mode phase contrast images were also taken in order to characterize the morphology and cellular structure changes of human hair at different humidity. The correlation between the nanomechanical properties and the cellular structure of hair is discussed

Quantitative Determination of Aluminum in Deodorant Brands: A Guided Inquiry Learning Experience in Quantitative Analysis Laboratory

Science.gov (United States)

Sedwick, Victoria; Leal, Anne; Turner, Dea; Kanu, A. Bakarr

2018-01-01

The monitoring of metals in commercial products is essential for protecting public health against the hazards of metal toxicity. This article presents a guided inquiry (GI) experimental lab approach in a quantitative analysis lab class that enabled students' to determine the levels of aluminum in deodorant brands. The utility of a GI experimental…

Quantitative data analysis with SPSS release 8 for Windows a guide for social scientists

CERN Document Server

Bryman, Alan

2002-01-01

The latest edition of this best-selling introduction to Quantitative Data Analysis through the use of a computer package has been completely updated to accommodate the needs of users of SPSS Release 8 for Windows. Like its predecessor, it provides a non-technical approach to quantitative data analysis and a user-friendly introduction to the widely used SPSS for Windows. It assumes no previous familiarity with either statistics or computing but takes the reader step-by-step through the techniques, reinforced by exercises for further practice. Techniques explained in Quantitative Data Analysis with SPSS Release 8 for Windows include: * correlation * simple and multiple regression * multivariate analysis of variance and covariance * factor analysis The book also covers issues such as sampling, statistical significance, conceptualization and measurement and the selection of appropriate tests. For further information or to download the book's datasets, please visit the webstite: http://www.routledge.com/textbooks/...

Quantitative analysis on electrooculography (EOG) for neurodegenerative disease

Science.gov (United States)

Liu, Chang-Chia; Chaovalitwongse, W. Art; Pardalos, Panos M.; Seref, Onur; Xanthopoulos, Petros; Sackellares, J. C.; Skidmore, Frank M.

2007-11-01

Many studies have documented abnormal horizontal and vertical eye movements in human neurodegenerative disease as well as during altered states of consciousness (including drowsiness and intoxication) in healthy adults. Eye movement measurement may play an important role measuring the progress of neurodegenerative diseases and state of alertness in healthy individuals. There are several techniques for measuring eye movement, Infrared detection technique (IR). Video-oculography (VOG), Scleral eye coil and EOG. Among those available recording techniques, EOG is a major source for monitoring the abnormal eye movement. In this real-time quantitative analysis study, the methods which can capture the characteristic of the eye movement were proposed to accurately categorize the state of neurodegenerative subjects. The EOG recordings were taken while 5 tested subjects were watching a short (>120 s) animation clip. In response to the animated clip the participants executed a number of eye movements, including vertical smooth pursued (SVP), horizontal smooth pursued (HVP) and random saccades (RS). Detection of abnormalities in ocular movement may improve our diagnosis and understanding a neurodegenerative disease and altered states of consciousness. A standard real-time quantitative analysis will improve detection and provide a better understanding of pathology in these disorders.

Quantitative XPS analysis of high Tc superconductor surfaces

International Nuclear Information System (INIS)

Jablonski, A.; Sanada, N.; Suzuki, Y.; Fukuda, Y.; Nagoshi, M.

1993-01-01

The procedure of quantitative XPS analysis involving the relative sensitivity factors is most convenient to apply to high T c superconductor surfaces because this procedure does not require standards. However, a considerable limitation of such an approach is its relatively low accuracy. In the present work, a proposition is made to use for this purpose a modification of the relative sensitivity factor approach accounting for the matrix and the instrumental effects. The accuracy of this modification when applied to the binary metal alloys is 2% or better. A quantitative XPS analysis was made for surfaces of the compounds Bi 2 Sr 2 CuO 6 , Bi 2 Sr 2 CaCu 2 O 8 , and YBa 2 Cu 3 O Y . The surface composition determined for the polycrystalline samples corresponds reasonably well to the bulk stoichiometry. Slight deficiency of oxygen was found for the Bi-based compounds. The surface exposed on cleavage of the Bi 2 Sr 2 CaCu 2 O 8 single crystal was found to be enriched with bismuth, which indicates that the cleavage occurs along the BiO planes. This result is in agreement with the STM studies published in the literature

Quantitative Analysis of Complex Tropical Forest Stands: A Review ...

African Journals Online (AJOL)

The importance of data analysis in quantitative assessment of natural resources remains significant in the sustainable management of complex tropical forest resources. Analyses of data from complex tropical forest stands have not been easy or clear due to improper data management. It is pivotal to practical researches ...

Local anodic oxidation by AFM tip developed for novel semiconductor nanodevices

International Nuclear Information System (INIS)

Cambel, Vladimir; Martaus, Jozef; Soltys, Jan; Kudela, Robert; Gregusova, Dagmar

2008-01-01

The local anodic oxidation (LAO) by the tip of atomic force microscope (AFM) is used for fabrication of nanometer-scaled structures and devices. We study the technology of LAO applied to semiconductor heterostructures, theoretically and experimentally as well. The goal is to improve the LAO process itself, i.e., to create narrow LAO lines that form high-energy barriers in the plane with the 2D electron gas. In the first part we show the electric field distribution in the system tip-sample during LAO. For samples with low-conductive cap layer the maximum electric field is shifted apart the tip apex, which leads to wide oxide lines. Our Monte Carlo (MC) calculations show how the height of the energy barrier in the system depends on the geometry of the created lines (trenches), and on voltage applied to the structure. Based on the calculations, we have proposed a novel LAO technology and applied it to InGaP/AlGaAs/GaAs heterostructure with doping layer only 6 nm beneath the surface. The doping layer can be oxidized easily by the AFM tip in this case, and the oxide objects can be removed by several etchants. This approach to the LAO technology leads to narrow LAO trenches (∼60 nm) and to energy barriers high enough for room- and low-temperature applications

AFM of the ultrastructural and mechanical properties of lipid-raft-disrupted and/or cold-treated endothelial cells.

Science.gov (United States)

Wu, Li; Huang, Jie; Yu, Xiaoxue; Zhou, Xiaoqing; Gan, Chaoye; Li, Ming; Chen, Yong

2014-02-01

The nonionic detergent extraction at 4 °C and the cholesterol-depletion-induced lipid raft disruption are the two widely used experimental strategies for lipid raft research. However, the effects of raft disruption and/or cold treatment on the ultrastructural and mechanical properties of cells are still unclear. Here, we evaluated the effects of raft disruption and/or cold (4 °C) treatment on these properties of living human umbilical vein endothelial cells (HUVECs). At first, the cholesterol-depletion-induced raft disruption was visualized by confocal microscopy and atomic force microscopy (AFM) in combination with fluorescent quantum dots. Next, the cold-induced cell contraction and the formation of end-branched filopodia were observed by confocal microscopy and AFM. Then, the cell-surface ultrastructures were imaged by AFM, and the data showed that raft disruption and cold treatment induced opposite effects on cell-surface roughness (a significant decrease and a significant increase, respectively). Moreover, the cell-surface mechanical properties (stiffness and adhesion force) of raft-disrupted- and/or cold-treated HUVECs were measured by the force measurement function of AFM. We found that raft disruption and cold treatment induced parallel effects on cell stiffness (increase) or adhesion force (decrease) and that the combination of the two treatments caused dramatically strengthened effects. Finally, raft disruption was found to significantly impair cell migration as previously reported, whereas temporary cold treatment only caused a slight but nonsignificant decrease in cell migration performed at physiological temperature. Although the mechanisms for causing these results might be complicated and more in-depth studies will be needed, our data may provide important information for better understanding the effects of raft disruption or cold treatment on cells and the two strategies for lipid raft research.

AFM and SEM study of the effects of etching on IPS-Empress 2 TM dental ceramic

Science.gov (United States)

Luo, X.-P.; Silikas, N.; Allaf, M.; Wilson, N. H. F.; Watts, D. C.

2001-10-01

The aim of this study was to investigate the effects of increasing etching time on the surface of the new dental material, IPS-Empress 2 TM glass ceramic. Twenty one IPS-Empress 2 TM glass ceramic samples were made from IPS-Empress 2 TM ingots through lost-wax, hot-pressed ceramic fabrication technology. All samples were highly polished and cleaned ultrasonically for 5 min in acetone before and after etching with 9.6% hydrofluoric acid gel. The etching times were 0, 10, 20, 30, 60, 90 and 120 s respectively. Microstructure was analysed by scanning electron microscopy (SEM) and atomic force microscopy (AFM) was used to evaluate the surface roughness and topography. Observations with SEM showed that etching with hydrofluoric acid resulted in preferential dissolution of glass matrix, and that partially supported crystals within the glass matrix were lost with increasing etching time. AFM measurements indicated that etching increased the surface roughness of the glass-ceramic. A simple least-squares linear regression was used to establish a relationship between surface roughness parameters ( Ra, RMS), and etching time, for which r2>0.94. This study demonstrates the benefits of combining two microscopic methods for a better understanding of the surface. SEM showed the mode of action of hydrofluoric acid on the ceramic and AFM provided valuable data regarding the extent of surface degradation relative to etching time.

Quantitative analysis of eyes and other optical systems in linear optics.

Science.gov (United States)

Harris, William F; Evans, Tanya; van Gool, Radboud D

2017-05-01

To show that 14-dimensional spaces of augmented point P and angle Q characteristics, matrices obtained from the ray transference, are suitable for quantitative analysis although only the latter define an inner-product space and only on it can one define distances and angles. The paper examines the nature of the spaces and their relationships to other spaces including symmetric dioptric power space. The paper makes use of linear optics, a three-dimensional generalization of Gaussian optics. Symmetric 2 × 2 dioptric power matrices F define a three-dimensional inner-product space which provides a sound basis for quantitative analysis (calculation of changes, arithmetic means, etc.) of refractive errors and thin systems. For general systems the optical character is defined by the dimensionally-heterogeneous 4 × 4 symplectic matrix S, the transference, or if explicit allowance is made for heterocentricity, the 5 × 5 augmented symplectic matrix T. Ordinary quantitative analysis cannot be performed on them because matrices of neither of these types constitute vector spaces. Suitable transformations have been proposed but because the transforms are dimensionally heterogeneous the spaces are not naturally inner-product spaces. The paper obtains 14-dimensional spaces of augmented point P and angle Q characteristics. The 14-dimensional space defined by the augmented angle characteristics Q is dimensionally homogenous and an inner-product space. A 10-dimensional subspace of the space of augmented point characteristics P is also an inner-product space. The spaces are suitable for quantitative analysis of the optical character of eyes and many other systems. Distances and angles can be defined in the inner-product spaces. The optical systems may have multiple separated astigmatic and decentred refracting elements. © 2017 The Authors Ophthalmic & Physiological Optics © 2017 The College of Optometrists.

Coating of AFM probes with aquatic humic and non-humic NOM to study their adhesion properties

KAUST Repository

Aubry, Cyril; Gutié rrez, Leonardo A.; Croue, Jean-Philippe

2013-01-01

-coated colloidal probes. AFM-generated force-distance curves were analyzed to elucidate the nature and mechanisms of these interacting forces. Electrostatics and steric interactions were important contributors to repulsive forces during approach, although

Quantitative X ray analysis system. User's manual and guide to X ray fluorescence technique

International Nuclear Information System (INIS)

2009-01-01

This guide covers trimmed and re-arranged version 3.6 of the Quantitative X ray Analysis System (QXAS) software package that includes the most frequently used methods of quantitative analysis. QXAS is a comprehensive quantitative analysis package that has been developed by the IAEA through research and technical contracts. Additional development has also been carried out in the IAEA Laboratories in Seibersdorf where QXAS was extensively tested. New in this version of the manual are the descriptions of the Voigt-profile peak fitting, the backscatter fundamental parameters' and emission-transmission methods of chemical composition analysis, an expanded chapter on the X ray fluorescence physics, and completely revised and increased number of practical examples of utilization of the QXAS software package. The analytical data accompanying this manual were collected in the IAEA Seibersdorf Laboratories in the years 2006/2007

Quantitative proteomic analysis of intact plastids.

Science.gov (United States)

Shiraya, Takeshi; Kaneko, Kentaro; Mitsui, Toshiaki

2014-01-01

Plastids are specialized cell organelles in plant cells that are differentiated into various forms including chloroplasts, chromoplasts, and amyloplasts, and fulfill important functions in maintaining the overall cell metabolism and sensing environmental factors such as sunlight. It is therefore important to grasp the mechanisms of differentiation and functional changes of plastids in order to enhance the understanding of vegetality. In this chapter, details of a method for the extraction of intact plastids that makes analysis possible while maintaining the plastid functions are provided; in addition, a quantitative shotgun method for analyzing the composition and changes in the content of proteins in plastids as a result of environmental impacts is described.

Investigation of the influence of UV irradiation on collagen thin films by AFM imaging

Energy Technology Data Exchange (ETDEWEB)

Stylianou, Andreas, E-mail: styliand@mail.ntua.gr; Yova, Dido; Alexandratou, Eleni

2014-12-01

Collagen is the major fibrous extracellular matrix protein and due to its unique properties, it has been widely used as biomaterial, scaffold and cell-substrate. The aim of the paper was to use Atomic Force Microscopy (AFM) in order to investigate well-characterized collagen thin films after ultraviolet light (UV) irradiation. The films were also used as in vitro culturing substrates in order to investigate the UV-induced alterations to fibroblasts. A special attention was given in the alteration on collagen D-periodicity. For short irradiation times, spectroscopy (fluorescence/absorption) studies demonstrated that photodegradation took place and AFM imaging showed alterations in surface roughness. Also, it was highlighted that UV-irradiation had different effects when it was applied on collagen solution than on films. Concerning fibroblast culturing, it was shown that fibroblast behavior was affected after UV irradiation of both collagen solution and films. Furthermore, after a long irradiation time, collagen fibrils were deformed revealing that collagen fibrils are consisting of multiple shells and D-periodicity occurred on both outer and inner shells. The clarification of the effects of UV light on collagen and the induced modifications of cell behavior on UV-irradiated collagen-based surfaces will contribute to the better understanding of cell–matrix interactions in the nanoscale and will assist in the appropriate use of UV light for sterilizing and photo-cross-linking applications. - Highlights: • Collagen thin films were formed and exposed in UV irradiation. • Collagen thin films were formed from UV-irradiated collagen solution. • Nanocharacterization of collagen thin films by AFM • Fluorescence and absorption spectroscopy studies on collagen films • Investigation of fibroblast response on collagen films.

Investigation of the influence of UV irradiation on collagen thin films by AFM imaging

International Nuclear Information System (INIS)

Stylianou, Andreas; Yova, Dido; Alexandratou, Eleni

2014-01-01

Collagen is the major fibrous extracellular matrix protein and due to its unique properties, it has been widely used as biomaterial, scaffold and cell-substrate. The aim of the paper was to use Atomic Force Microscopy (AFM) in order to investigate well-characterized collagen thin films after ultraviolet light (UV) irradiation. The films were also used as in vitro culturing substrates in order to investigate the UV-induced alterations to fibroblasts. A special attention was given in the alteration on collagen D-periodicity. For short irradiation times, spectroscopy (fluorescence/absorption) studies demonstrated that photodegradation took place and AFM imaging showed alterations in surface roughness. Also, it was highlighted that UV-irradiation had different effects when it was applied on collagen solution than on films. Concerning fibroblast culturing, it was shown that fibroblast behavior was affected after UV irradiation of both collagen solution and films. Furthermore, after a long irradiation time, collagen fibrils were deformed revealing that collagen fibrils are consisting of multiple shells and D-periodicity occurred on both outer and inner shells. The clarification of the effects of UV light on collagen and the induced modifications of cell behavior on UV-irradiated collagen-based surfaces will contribute to the better understanding of cell–matrix interactions in the nanoscale and will assist in the appropriate use of UV light for sterilizing and photo-cross-linking applications. - Highlights: • Collagen thin films were formed and exposed in UV irradiation. • Collagen thin films were formed from UV-irradiated collagen solution. • Nanocharacterization of collagen thin films by AFM • Fluorescence and absorption spectroscopy studies on collagen films • Investigation of fibroblast response on collagen films

Quantitative analysis of elastography images in the detection of breast cancer

International Nuclear Information System (INIS)

Landoni, V.; Francione, V.; Marzi, S.; Pasciuti, K.; Ferrante, F.; Saracca, E.; Pedrini, M.; Strigari, L.; Crecco, M.; Di Nallo, A.

2012-01-01

Purpose: The aim of this study was to develop a quantitative method for breast cancer diagnosis based on elastosonography images in order to reduce whenever possible unnecessary biopsies. The proposed method was validated by correlating the results of quantitative analysis with the diagnosis assessed by histopathologic exam. Material and methods: 109 images of breast lesions (50 benign and 59 malignant) were acquired with the traditional B-mode technique and with elastographic modality. Images in Digital Imaging and COmmunications in Medicine format (DICOM) were exported into a software, written in Visual Basic, especially developed to perform this study. The lesion was contoured and the mean grey value and softness inside the region of interest (ROI) were calculated. The correlations between variables were investigated and receiver operating characteristic (ROC) curve analysis was performed to assess the diagnostic accuracy of the proposed method. Pathologic results were used as standard reference. Results: Both the mean grey value and the softness inside the ROI resulted statistically different at the t test for the two populations of lesions (i.e., benign versus malignant): p < 0.0001. The area under the curve (AUC) was 0.924 (0.834–0.973) and 0.917 (0.826–0.970) for the mean grey value and for the softness respectively. Conclusions: Quantitative elastosonography is a promising ultrasound technique in the detection of breast cancer but large prospective trials are necessary to determine whether quantitative analysis of images can help to overcome some pitfalls of the methodic.

Renal geology (quantitative renal stone analysis) by 'Fourier transform infrared spectroscopy'.

Science.gov (United States)

Singh, Iqbal

2008-01-01

To prospectively determine the precise stone composition (quantitative analysis) by using infrared spectroscopy in patients with urinary stone disease presenting to our clinic. To determine an ideal method for stone analysis suitable for use in a clinical setting. After routine and a detailed metabolic workup of all patients of urolithiasis, stone samples of 50 patients of urolithiasis satisfying the entry criteria were subjected to the Fourier transform infrared spectroscopic analysis after adequate sample homogenization at a single testing center. Calcium oxalate monohydrate and dihydrate stone mixture was most commonly encountered in 35 (71%) followed by calcium phosphate, carbonate apatite, magnesium ammonium hexahydrate and xanthine stones. Fourier transform infrared spectroscopy allows an accurate, reliable quantitative method of stone analysis. It also helps in maintaining a computerized large reference library. Knowledge of precise stone composition may allow the institution of appropriate prophylactic therapy despite the absence of any detectable metabolic abnormalities. This may prevent and or delay stone recurrence.

Quantitative proteomic analysis of ibuprofen-degrading Patulibacter sp. strain I11

DEFF Research Database (Denmark)

Almeida, Barbara; Kjeldal, Henrik; Lolas, Ihab Bishara Yousef

2013-01-01

was identified and quantified by gel based shotgun-proteomics. In total 251 unique proteins were quantitated using this approach. Biological process and pathway analysis indicated a number of proteins that were up-regulated in response to active degradation of ibuprofen, some of them are known to be involved...... in the degradation of aromatic compounds. Data analysis revealed that several of these proteins are likely involved in ibuprofen degradation by Patulibacter sp. strain I11.......Ibuprofen is the third most consumed pharmaceutical drug in the world. Several isolates have been shown to degrade ibuprofen, but very little is known about the biochemistry of this process. This study investigates the degradation of ibuprofen by Patulibacter sp. strain I11 by quantitative...

Nanopuller-open data acquisition platform for AFM force spectroscopy experiments

International Nuclear Information System (INIS)

Pawlak, Konrad; Strzelecki, Janusz

2016-01-01

Atomic Force Microscope (AFM) is a widely used tool in force spectroscopy studies. Presently, this instrument is accessible from numerous vendors, albeit commercial solutions are expensive and almost always hardware and software closed. Approaches for open setups were published, as with modern low cost and readily available piezoelectric actuators, data acquisition interfaces and optoelectronic components building such force spectroscopy AFM is relatively easy. However, suitable software to control such laboratory made instrument was not released. Developing it in the lab requires significant time and effort. Our Nanopuller software described in this paper is intended to eliminate this obstacle. With only minimum adjustments this program can be used to control and acquire data with any suitable National Instruments universal digital/analog interface and piezoelectric actuator analog controller, giving significant freedom and flexibility in designing force spectroscopy experiment. Since the full code, written in a graphical LabVIEW environment is available, our Nanopuller can be easily customized. In this paper we describe the program and test its performance in controlling different setups. Successful and accurate force curve acquisition for standard samples (single molecules of I27O reference titin polyprotein and DNA as well as red blood cells) is shown. - Highlights: • We created open data acquisition software for performing Atomic Force Microscopy force measurements with custom laboratory made setups. • The software allows large flexibility in atomic force microscope design with minimum adjustment necessary. • The software is written in LabVIEW, allowing easy customization. • We successfully tested the program on two different hardware configurations by stretching single macromolecules and indenting cells.

Nanopuller-open data acquisition platform for AFM force spectroscopy experiments

Energy Technology Data Exchange (ETDEWEB)

Pawlak, Konrad; Strzelecki, Janusz

2016-05-15

Atomic Force Microscope (AFM) is a widely used tool in force spectroscopy studies. Presently, this instrument is accessible from numerous vendors, albeit commercial solutions are expensive and almost always hardware and software closed. Approaches for open setups were published, as with modern low cost and readily available piezoelectric actuators, data acquisition interfaces and optoelectronic components building such force spectroscopy AFM is relatively easy. However, suitable software to control such laboratory made instrument was not released. Developing it in the lab requires significant time and effort. Our Nanopuller software described in this paper is intended to eliminate this obstacle. With only minimum adjustments this program can be used to control and acquire data with any suitable National Instruments universal digital/analog interface and piezoelectric actuator analog controller, giving significant freedom and flexibility in designing force spectroscopy experiment. Since the full code, written in a graphical LabVIEW environment is available, our Nanopuller can be easily customized. In this paper we describe the program and test its performance in controlling different setups. Successful and accurate force curve acquisition for standard samples (single molecules of I27O reference titin polyprotein and DNA as well as red blood cells) is shown. - Highlights: • We created open data acquisition software for performing Atomic Force Microscopy force measurements with custom laboratory made setups. • The software allows large flexibility in atomic force microscope design with minimum adjustment necessary. • The software is written in LabVIEW, allowing easy customization. • We successfully tested the program on two different hardware configurations by stretching single macromolecules and indenting cells.

Analysis association of milk fat and protein percent in quantitative ...

African Journals Online (AJOL)

Analysis association of milk fat and protein percent in quantitative trait locus ... African Journal of Biotechnology ... Protein and fat percent as content of milk are high-priority criteria for financial aims and selection of programs in dairy cattle.

Contribution of the surface contamination of uranium-materials on the quantitative analysis results by electron probe microbeam analysis

International Nuclear Information System (INIS)

Bonino, O.; Fournier, C.; Fucili, C.; Dugne, O.; Merlet, C.

2000-01-01

The analytical testing of uranium materials is necessary for quality research and development in nuclear industry applications (enrichment, safety studies, fuel, etc). Electron Probe Microbeam Analysis Wavelength Dispersive Spectrometry (EPMA-WDS) is a dependable non-destructive analytical technology. The characteristic X-ray signal is measured to identify and quantify the sample components, and the analyzed volume is about one micron cube. The surface contamination of uranium materials modifies and contributes to the quantitative analysis results of EPMA-WDS. This contribution is not representative of the bulk. A thin oxidized layer appears in the first instants after preparation (burnishing, cleaning) as well as a carbon contamination layer, due to metallographic preparation and carbon cracking under the impact of the electron probe. Several analytical difficulties subsequently arise, including an overlapping line between the carbon Ka ray and the Uranium U NIVOVI ray. Sensitivity and accuracy of the quantification of light elements like carbon and oxygen are also reduced by the presence of uranium. The aim of this study was to improve the accuracy of quantitative analysis on uranium materials by EPMA-WDS by taking account of the contribution of surface contamination. The first part of this paper is devoted to the study of the contaminated surface of the uranium materials U, UFe 2 and U 6 Fe a few hours after preparation. These oxidation conditions are selected so as to reproduce the same contamination surfaces occurring in microprobe analytical conditions. Surface characterization techniques were SIMS and Auger spectroscopy. The contaminated surfaces are shown. They consist of successive layers: a carbon layer, an oxidized iron layer, followed by an iron depletion layer (only in UFe 2 and U 6 Fe), and a ternary oxide layer (U-Fe-O for UFe 2 et U 6 Fe and UO 2+x for uranium). The second part of the paper addresses the estimation of the errors in quantitative

A new quantitative analysis on nitriding kinetics in the oxidized Zry-4 at 900-1200 .deg. C

Energy Technology Data Exchange (ETDEWEB)

Park, Sanggi [ACT Co. Ltd., Daejeon (Korea, Republic of)

2016-10-15

Two major roles of nitrogen on the zirconium based cladding degradation were identified: mechanical degradation of the cladding, and the additional chemical heat release. It has long been known that accelerated oxidation can occur in air due to the nitrogen. In addition, significant uptake of nitrogen can also occur. The nitriding of pre-oxidized zirconium based alloys leads to micro porous and less coherent oxide scales. This paper aims to quantitatively investigate the nitriding mechanism and kinetics by proposing a new methodology that is coupled with the mass balance analysis and the optical microscope image processing analysis. A new quantitative analysis methodology is described in chapter 2 and the investigation of the nitriding kinetics is performed in chapter 3. The experimental details are previously reported in. Previously only qualitative analysis was performed in, and hence the quantitative analysis will be performed in this paper. In this paper, the nitriding kinetics and mechanism were quantitatively analyzed by the new proposed analysis methods: the mass balance analysis and the optical microscope image processing analysis. Using these combined methods, the mass gain curves and the optical microscopes are analyzed in very detail, and the mechanisms of nitriding accelerated, stabilized and saturated behaviors were well understood. This paper has two very distinctive achievements as follows: 1) Development of very effective quantitative analysis methods only using two main results of oxidation tests: No detailed analytical sample measurements (e.g. TEM, EPMA and so on.) were required. These methods can effectively reduce the cost and effort of the post-test investigation. 2) The first identification of the nitriding behaviors and its very accurate analysis in a quantitative way. Based on this quantitative analysis results on the nitriding kinetics, these new findings will contribute significantly the understanding the air oxidation behaviors and model

Patient-specific coronary blood supply territories for quantitative perfusion analysis

Science.gov (United States)

Zakkaroff, Constantine; Biglands, John D.; Greenwood, John P.; Plein, Sven; Boyle, Roger D.; Radjenovic, Aleksandra; Magee, Derek R.

2018-01-01

Abstract Myocardial perfusion imaging, coupled with quantitative perfusion analysis, provides an important diagnostic tool for the identification of ischaemic heart disease caused by coronary stenoses. The accurate mapping between coronary anatomy and under-perfused areas of the myocardium is important for diagnosis and treatment. However, in the absence of the actual coronary anatomy during the reporting of perfusion images, areas of ischaemia are allocated to a coronary territory based on a population-derived 17-segment (American Heart Association) AHA model of coronary blood supply. This work presents a solution for the fusion of 2D Magnetic Resonance (MR) myocardial perfusion images and 3D MR angiography data with the aim to improve the detection of ischaemic heart disease. The key contribution of this work is a novel method for the mediated spatiotemporal registration of perfusion and angiography data and a novel method for the calculation of patient-specific coronary supply territories. The registration method uses 4D cardiac MR cine series spanning the complete cardiac cycle in order to overcome the under-constrained nature of non-rigid slice-to-volume perfusion-to-angiography registration. This is achieved by separating out the deformable registration problem and solving it through phase-to-phase registration of the cine series. The use of patient-specific blood supply territories in quantitative perfusion analysis (instead of the population-based model of coronary blood supply) has the potential of increasing the accuracy of perfusion analysis. Quantitative perfusion analysis diagnostic accuracy evaluation with patient-specific territories against the AHA model demonstrates the value of the mediated spatiotemporal registration in the context of ischaemic heart disease diagnosis. PMID:29392098

Quantitative analysis of γ–oryzanol content in cold pressed rice bran oil by TLC–image analysis method

Directory of Open Access Journals (Sweden)

Apirak Sakunpak

2014-02-01

Conclusions: The TLC-densitometric and TLC-image analysis methods provided a similar reproducibility, accuracy and selectivity for the quantitative determination of γ-oryzanol in cold pressed rice bran oil. A statistical comparison of the quantitative determinations of γ-oryzanol in samples did not show any statistically significant difference between TLC-densitometric and TLC-image analysis methods. As both methods were found to be equal, they therefore can be used for the determination of γ-oryzanol in cold pressed rice bran oil.

Friction behavior of nano-textured polyimide surfaces measured by AFM colloidal probe

Energy Technology Data Exchange (ETDEWEB)

Zhang, Xiaoliang [College of Equipment Manufacturing, Hebei University of Engineering, Handan 056038 (China); State Key Laboratory of Solid Lubrication, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou 730000 (China); Wu, Chunxia; Che, Hongwei; Hou, Junxian [College of Equipment Manufacturing, Hebei University of Engineering, Handan 056038 (China); Jia, Junhong, E-mail: jhjia@licp.cas.cn [State Key Laboratory of Solid Lubrication, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou 730000 (China)

2014-11-30

Highlights: • Flat PI film and nano-textured PI film were prepared by spin-coating process. • The nano-textured PI surface has effectively reduced the adhesion and friction. • Friction increased with the increasing of contact area and adhesion. • The growth rate of friction decreased with the increasing of applied load. - Abstract: Flat polyimide (PI) film and silicon dioxide nanoparticle-textured PI film were prepared by means of the spin-coating technique. The adhesion and friction properties of the flat PI surface and nano-textured PI surface were investigated by a series of Atomic force microscope (AFM) colloidal probes. Experimental results revealed that the nano-textured PI surface can significantly reduce the adhesive force and friction force, compared with the flat PI surface. The main reason is that the nano-textures can reduce the contact area between the sample surface and colloidal probe. The effect of colloidal probe size on the friction behavior of the flat and nano-textured PI surfaces was evaluated. The adhesive force and friction force of nano-textured PI surface were increased with the increasing of the size of interacting pairs (AFM colloidal probe) due to the increased contact area. Moreover, the friction forces of flat and nano-textured PI surfaces were increased with applied load and sliding velocity.

Adhesive interaction measured between AFM probe and lung epithelial type II cells

International Nuclear Information System (INIS)

Leonenko, Zoya; Finot, Eric; Amrein, Matthias

2007-01-01

The toxicity of inhaled nanoparticles entering the body through the lung is thought to be initially defined by the electrostatic and adhesive interaction of the particles with lung's wall. Here, we investigated the first step of the interaction of nanoparticles with lung epithelial cells using atomic force microscope (AFM) as a force apparatus. Nanoparticles were modeled by the apex of the AFM tip and the forces of interaction between the tip and the cell analyzed over time. The adhesive force and work of adhesion strongly increased for the first 100 s of contact and then leveled out. During this time, the tip was penetrating deeply into the cell. It first crossed a stiff region of the cell and then entered a much more compliant cell region. The work of adhesion and its progression over time were not dependent on the load with which the tip was brought into contact with the cell. We conclude that the initial thermodynamic aspects and the time course of the uptake of nanoparticles by lung epithelial cells can be studied using our experimental approach. It is discussed how the potential health threat posed by nanoparticles of different size and surface characteristics can be evaluated using the method presented

Spontaneous aggregation of humic acid observed with AFM at different pH.

Science.gov (United States)

Colombo, Claudio; Palumbo, Giuseppe; Angelico, Ruggero; Cho, Hyen Goo; Francioso, Ornella; Ertani, Andrea; Nardi, Serenella

2015-11-01

Atomic force microscopy in contact (AFM-C) mode was used to investigate the molecular dynamics of leonardite humic acid (HA) aggregate formed at different pH values. HA nanoparticles dispersed at pH values ranging from 2 to 12 were observed on a mica surface under dry conditions. The most clearly resolved and well-resulted AFM images of single particle were obtained at pH 5, where HA appeared as supramolecular particles with a conic shape and a hole in the centre. Those observations suggested that HA formed under these conditions exhibited a pseudo-amphiphilic nature, with secluded hydrophobic domains and polar subunits in direct contact with hydrophilic mica surface. Based on molecular simulation methods, a lignin-carbohydrate complex (LCC) model was proposed to explain the HA ring-like morphology. The LCC model optimized the parameters of β-O-4 linkages between 14 units of 1-4 phenyl propanoid, and resulted in an optimized structure comprising 45-50 linear helical molecules looped spirally around a central cavity. Those results added new insights on the adsorption mechanism of HA on polar surfaces as a function of pH, which was relevant from the point of view of natural aggregation in soil environment. Copyright © 2015 Elsevier Ltd. All rights reserved.

Optimal climate policy is a utopia. From quantitative to qualitative cost-benefit analysis

International Nuclear Information System (INIS)

Van den Bergh, Jeroen C.J.M.

2004-01-01

The dominance of quantitative cost-benefit analysis (CBA) and optimality concepts in the economic analysis of climate policy is criticised. Among others, it is argued to be based in a misplaced interpretation of policy for a complex climate-economy system as being analogous to individual inter-temporal welfare optimisation. The transfer of quantitative CBA and optimality concepts reflects an overly ambitious approach that does more harm than good. An alternative approach is to focus the attention on extreme events, structural change and complexity. It is argued that a qualitative rather than a quantitative CBA that takes account of these aspects can support the adoption of a minimax regret approach or precautionary principle in climate policy. This means: implement stringent GHG reduction policies as soon as possible

Method of quantitative analysis of superconducting metal-conducting composite materials

International Nuclear Information System (INIS)

Bogomolov, V.N.; Zhuravlev, V.V.; Petranovskij, V.P.; Pimenov, V.A.

1990-01-01

Technique for quantitative analysis of superconducting metal-containing composite materials, SnO 2 -InSn, WO 3 -InW, Zn)-InZn in particular, has been developed. The method of determining metal content in a composite is based on the dependence of superconducting transition temperature on alloy composition. Sensitivity of temperature determination - 0.02K, error of analysis for InSn system - 0.5%

Meta-analysis for quantitative microbiological risk assessments and benchmarking data

NARCIS (Netherlands)

Besten, den H.M.W.; Zwietering, M.H.

2012-01-01

Meta-analysis studies are increasingly being conducted in the food microbiology area to quantitatively integrate the findings of many individual studies on specific questions or kinetic parameters of interest. Meta-analyses provide global estimates of parameters and quantify their variabilities, and

Visual and Quantitative Analysis Methods of Respiratory Patterns for Respiratory Gated PET/CT.

Science.gov (United States)

Son, Hye Joo; Jeong, Young Jin; Yoon, Hyun Jin; Park, Jong-Hwan; Kang, Do-Young

2016-01-01

We integrated visual and quantitative methods for analyzing the stability of respiration using four methods: phase space diagrams, Fourier spectra, Poincaré maps, and Lyapunov exponents. Respiratory patterns of 139 patients were grouped based on the combination of the regularity of amplitude, period, and baseline positions. Visual grading was done by inspecting the shape of diagram and classified into two states: regular and irregular. Quantitation was done by measuring standard deviation of x and v coordinates of Poincaré map (SD x , SD v ) or the height of the fundamental peak ( A 1 ) in Fourier spectrum or calculating the difference between maximal upward and downward drift. Each group showed characteristic pattern on visual analysis. There was difference of quantitative parameters (SD x , SD v , A 1 , and MUD-MDD) among four groups (one way ANOVA, p = 0.0001 for MUD-MDD, SD x , and SD v , p = 0.0002 for A 1 ). In ROC analysis, the cutoff values were 0.11 for SD x (AUC: 0.982, p quantitative indices of respiratory stability and determining quantitative cutoff value for differentiating regular and irregular respiration.

GProX, a user-friendly platform for bioinformatics analysis and visualization of quantitative proteomics data.

Science.gov (United States)

Rigbolt, Kristoffer T G; Vanselow, Jens T; Blagoev, Blagoy

2011-08-01

Recent technological advances have made it possible to identify and quantify thousands of proteins in a single proteomics experiment. As a result of these developments, the analysis of data has become the bottleneck of proteomics experiment. To provide the proteomics community with a user-friendly platform for comprehensive analysis, inspection and visualization of quantitative proteomics data we developed the Graphical Proteomics Data Explorer (GProX)(1). The program requires no special bioinformatics training, as all functions of GProX are accessible within its graphical user-friendly interface which will be intuitive to most users. Basic features facilitate the uncomplicated management and organization of large data sets and complex experimental setups as well as the inspection and graphical plotting of quantitative data. These are complemented by readily available high-level analysis options such as database querying, clustering based on abundance ratios, feature enrichment tests for e.g. GO terms and pathway analysis tools. A number of plotting options for visualization of quantitative proteomics data is available and most analysis functions in GProX create customizable high quality graphical displays in both vector and bitmap formats. The generic import requirements allow data originating from essentially all mass spectrometry platforms, quantitation strategies and software to be analyzed in the program. GProX represents a powerful approach to proteomics data analysis providing proteomics experimenters with a toolbox for bioinformatics analysis of quantitative proteomics data. The program is released as open-source and can be freely downloaded from the project webpage at http://gprox.sourceforge.net.

Analysis of archaeological ceramics by total-reflection X-ray fluorescence: Quantitative approaches

International Nuclear Information System (INIS)

Fernandez-Ruiz, R.; Garcia-Heras, M.

2008-01-01

This paper reports the quantitative methodologies developed for the compositional characterization of archaeological ceramics by total-reflection X-ray fluorescence at two levels. A first quantitative level which comprises an acid leaching procedure, and a second selective level, which seeks to increase the number of detectable elements by eliminating the iron present in the acid leaching procedure. Total-reflection X-ray fluorescence spectrometry has been compared, at a quantitative level, with Instrumental Neutron Activation Analysis in order to test its applicability to the study of this kind of materials. The combination of a solid chemical homogenization procedure previously reported with the quantitative methodologies here presented allows the total-reflection X-ray fluorescence to analyze 29 elements with acceptable analytical recoveries and accuracies

Analysis of archaeological ceramics by total-reflection X-ray fluorescence: Quantitative approaches

Energy Technology Data Exchange (ETDEWEB)

Fernandez-Ruiz, R. [Servicio Interdepartamental de Investigacion, Facultad de Ciencias, Universidad Autonoma de Madrid, Modulo C-9, Laboratorio de TXRF, Crta. Colmenar, Km 15, Cantoblanco, E-28049, Madrid (Spain)], E-mail: ramon.fernandez@uam.es; Garcia-Heras, M. [Grupo de Arqueometria de Vidrios y Materiales Ceramicos, Instituto de Historia, Centro de Ciencias Humanas y Sociales, CSIC, C/ Albasanz, 26-28, 28037 Madrid (Spain)

2008-09-15

This paper reports the quantitative methodologies developed for the compositional characterization of archaeological ceramics by total-reflection X-ray fluorescence at two levels. A first quantitative level which comprises an acid leaching procedure, and a second selective level, which seeks to increase the number of detectable elements by eliminating the iron present in the acid leaching procedure. Total-reflection X-ray fluorescence spectrometry has been compared, at a quantitative level, with Instrumental Neutron Activation Analysis in order to test its applicability to the study of this kind of materials. The combination of a solid chemical homogenization procedure previously reported with the quantitative methodologies here presented allows the total-reflection X-ray fluorescence to analyze 29 elements with acceptable analytical recoveries and accuracies.

Study on methods of quantitative analysis of the biological thin samples in EM X-ray microanalysis

International Nuclear Information System (INIS)

Zhang Detian; Zhang Xuemin; He Kun; Yang Yi; Zhang Sa; Wang Baozhen

2000-01-01

Objective: To study the methods of quantitative analysis of the biological thin samples. Methods: Hall theory was used to study the qualitative analysis, background subtraction, peel off overlap peaks; external radiation and aberrance of spectra. Results: The results of reliable qualitative analysis and precise quantitative analysis were achieved. Conclusion: The methods for analysis of the biological thin samples in EM X-ray microanalysis can be used in biomedical research

Quantitative x-ray fractographic analysis of fatigue fractures

International Nuclear Information System (INIS)

Saprykin, Yu.V.

1983-01-01

The study deals with quantitative X-ray fractographic investigation of fatigue fractures of samples with sharp notches tested at various stresses and temperatures with the purpose of establishing a connection between material crack resistance parameters and local plastic instability zones restraining and controlling the crack growth. At fatigue fractures of notched Kh18N9T steel samples tested at +20 and -196 deg C a zone of sharp ring notch effect being analogous to the zone in which crack growth rate is controlled by the microshifting mechanisms is singled out. The size of the notched effect zone in the investigate steel is unambiguosly bound to to the stress amplitude. This provides the possibility to determine the stress value by the results of quantitative fractographic analysis of notched sample fractures. A possibility of determining one of the threshold values of cyclic material fracture toughness by the results of fatigue testing and fractography of notched sample fractures is shown. Correlation between the size of the hsub(s) crack effect zone in the notched sample, delta material yield limit and characteristic of cyclic Ksub(s) fracture toughness has been found. Such correlation widens the possibilities of quantitative diagnostics of fractures by the methods of X-ray fractography

Wavelength Selection Method Based on Differential Evolution for Precise Quantitative Analysis Using Terahertz Time-Domain Spectroscopy.

Science.gov (United States)

Li, Zhi; Chen, Weidong; Lian, Feiyu; Ge, Hongyi; Guan, Aihong

2017-12-01

Quantitative analysis of component mixtures is an important application of terahertz time-domain spectroscopy (THz-TDS) and has attracted broad interest in recent research. Although the accuracy of quantitative analysis using THz-TDS is affected by a host of factors, wavelength selection from the sample's THz absorption spectrum is the most crucial component. The raw spectrum consists of signals from the sample and scattering and other random disturbances that can critically influence the quantitative accuracy. For precise quantitative analysis using THz-TDS, the signal from the sample needs to be retained while the scattering and other noise sources are eliminated. In this paper, a novel wavelength selection method based on differential evolution (DE) is investigated. By performing quantitative experiments on a series of binary amino acid mixtures using THz-TDS, we demonstrate the efficacy of the DE-based wavelength selection method, which yields an error rate below 5%.

Quantitative texture analysis of electrodeposited line patterns

DEFF Research Database (Denmark)

Pantleon, Karen; Somers, Marcel A.J.

2005-01-01

Free-standing line patterns of Cu and Ni were manufactured by electrochemical deposition into lithographically prepared patterns. Electrodeposition was carried out on top of a highly oriented Au-layer physically vapor deposited on glass. Quantitative texture analysis carried out by means of x......-ray diffraction for both the substrate layer and the electrodeposits yielded experimental evidence for epitaxy between Cu and Au. An orientation relation between film and substrate was discussed with respect to various concepts of epitaxy. While the conventional mode of epitaxy fails for the Cu...

Magnetoelectric versus thermal actuation characteristics of shear force AFM probes with piezoresistive detection

International Nuclear Information System (INIS)

Sierakowski, Andrzej; Janus, Paweł; Dobrowolski, Rafał; Grabiec, Piotr; Kopiec, Daniel; Majstrzyk, Wojciech; Kunicki, Piotr; Gotszalk, Teodor; Rangelow, Ivo W

2017-01-01

In this paper the authors compare methods used for piezoresistive microcantilevers actuation for the atomic force microscopy (AFM) imaging in the dynamic shear force mode. The piezoresistive detection is an attractive technique comparing the optical beam detection of deflection. The principal advantage is that no external alignment of optical source and detector are needed. When the microcantilever is deflected, the stress is transferred into a change of resistivity of piezoresistors. The integration of piezoresistive read-out provides a promising solution in realizing a compact non-contact AFM. Resolution of piezoresistive read-out is limited by three main noise sources: Johnson, 1/ f and thermomechanical noise. In the dynamic shear force mode measurement the method used for cantilever actuation will also affect the recorded noise in the piezoresistive detection circuit. This is the result of a crosstalk between an aluminium path (current loop used for actuation) and piezoresistors located near the base of the beam. In this paper authors described an elaborated in ITE (Institute of Electron Technology) technology of fabrication cantilevers with piezoresistive detection of deflection and compared efficiency of two methods used for cantilever actuation. (paper)

Joint analysis of binary and quantitative traits with data sharing and outcome-dependent sampling.

Science.gov (United States)

Zheng, Gang; Wu, Colin O; Kwak, Minjung; Jiang, Wenhua; Joo, Jungnam; Lima, Joao A C

2012-04-01

We study the analysis of a joint association between a genetic marker with both binary (case-control) and quantitative (continuous) traits, where the quantitative trait values are only available for the cases due to data sharing and outcome-dependent sampling. Data sharing becomes common in genetic association studies, and the outcome-dependent sampling is the consequence of data sharing, under which a phenotype of interest is not measured for some subgroup. The trend test (or Pearson's test) and F-test are often, respectively, used to analyze the binary and quantitative traits. Because of the outcome-dependent sampling, the usual F-test can be applied using the subgroup with the observed quantitative traits. We propose a modified F-test by also incorporating the genotype frequencies of the subgroup whose traits are not observed. Further, a combination of this modified F-test and Pearson's test is proposed by Fisher's combination of their P-values as a joint analysis. Because of the correlation of the two analyses, we propose to use a Gamma (scaled chi-squared) distribution to fit the asymptotic null distribution for the joint analysis. The proposed modified F-test and the joint analysis can also be applied to test single trait association (either binary or quantitative trait). Through simulations, we identify the situations under which the proposed tests are more powerful than the existing ones. Application to a real dataset of rheumatoid arthritis is presented. © 2012 Wiley Periodicals, Inc.

Investment appraisal using quantitative risk analysis.

Science.gov (United States)

Johansson, Henrik

2002-07-01

Investment appraisal concerned with investments in fire safety systems is discussed. Particular attention is directed at evaluating, in terms of the Bayesian decision theory, the risk reduction that investment in a fire safety system involves. It is shown how the monetary value of the change from a building design without any specific fire protection system to one including such a system can be estimated by use of quantitative risk analysis, the results of which are expressed in terms of a Risk-adjusted net present value. This represents the intrinsic monetary value of investing in the fire safety system. The method suggested is exemplified by a case study performed in an Avesta Sheffield factory.

GProX, a User-Friendly Platform for Bioinformatics Analysis and Visualization of Quantitative Proteomics Data

DEFF Research Database (Denmark)

Rigbolt, Kristoffer T G; Vanselow, Jens T; Blagoev, Blagoy

2011-01-01

-friendly platform for comprehensive analysis, inspection and visualization of quantitative proteomics data we developed the Graphical Proteomics Data Explorer (GProX)(1). The program requires no special bioinformatics training, as all functions of GProX are accessible within its graphical user-friendly interface...... such as database querying, clustering based on abundance ratios, feature enrichment tests for e.g. GO terms and pathway analysis tools. A number of plotting options for visualization of quantitative proteomics data is available and most analysis functions in GProX create customizable high quality graphical...... displays in both vector and bitmap formats. The generic import requirements allow data originating from essentially all mass spectrometry platforms, quantitation strategies and software to be analyzed in the program. GProX represents a powerful approach to proteomics data analysis providing proteomics...

Vickers Hardness of Diamond and cBN Single Crystals: AFM Approach

Directory of Open Access Journals (Sweden)

Sergey Dub

2017-12-01

Full Text Available Atomic force microscopy in different operation modes (topography, derivative topography, and phase contrast was used to obtain 3D images of Vickers indents on the surface of diamond and cBN single crystals with high spatial resolution. Confocal Raman spectroscopy and Kelvin probe force microscopy were used to study the structure of the material in the indents. It was found that Vickers indents in diamond has no sharp and clear borders. However, the phase contrast operation mode of the AFM reveals a new viscoelastic phase in the indent in diamond. Raman spectroscopy and Kelvin probe force microscopy revealed that the new phase in the indent is disordered graphite, which was formed due to the pressure-induced phase transformation in the diamond during the hardness test. The projected contact area of the graphite layer in the indent allows us to measure the Vickers hardness of type-Ib synthetic diamond. In contrast to diamond, very high plasticity was observed for 0.5 N load indents on the (001 cBN single crystal face. Radial and ring cracks were absent, the shape of the indents was close to a square, and there were linear details in the indent, which looked like slip lines. The Vickers hardness of the (111 synthetic diamond and (111 and (001 cBN single crystals were determined using the AFM images and with account for the elastic deformation of the diamond Vickers indenter during the tests.

Survival Prediction in Pancreatic Ductal Adenocarcinoma by Quantitative Computed Tomography Image Analysis.

Science.gov (United States)

Attiyeh, Marc A; Chakraborty, Jayasree; Doussot, Alexandre; Langdon-Embry, Liana; Mainarich, Shiana; Gönen, Mithat; Balachandran, Vinod P; D'Angelica, Michael I; DeMatteo, Ronald P; Jarnagin, William R; Kingham, T Peter; Allen, Peter J; Simpson, Amber L; Do, Richard K

2018-04-01

Pancreatic cancer is a highly lethal cancer with no established a priori markers of survival. Existing nomograms rely mainly on post-resection data and are of limited utility in directing surgical management. This study investigated the use of quantitative computed tomography (CT) features to preoperatively assess survival for pancreatic ductal adenocarcinoma (PDAC) patients. A prospectively maintained database identified consecutive chemotherapy-naive patients with CT angiography and resected PDAC between 2009 and 2012. Variation in CT enhancement patterns was extracted from the tumor region using texture analysis, a quantitative image analysis tool previously described in the literature. Two continuous survival models were constructed, with 70% of the data (training set) using Cox regression, first based only on preoperative serum cancer antigen (CA) 19-9 levels and image features (model A), and then on CA19-9, image features, and the Brennan score (composite pathology score; model B). The remaining 30% of the data (test set) were reserved for independent validation. A total of 161 patients were included in the analysis. Training and test sets contained 113 and 48 patients, respectively. Quantitative image features combined with CA19-9 achieved a c-index of 0.69 [integrated Brier score (IBS) 0.224] on the test data, while combining CA19-9, imaging, and the Brennan score achieved a c-index of 0.74 (IBS 0.200) on the test data. We present two continuous survival prediction models for resected PDAC patients. Quantitative analysis of CT texture features is associated with overall survival. Further work includes applying the model to an external dataset to increase the sample size for training and to determine its applicability.

Nanobiosensors Based on Chemically Modified AFM Probes: A Useful Tool for Metsulfuron-Methyl Detection

Directory of Open Access Journals (Sweden)

Fabio L. Leite

2013-01-01

Full Text Available The use of agrochemicals has increased considerably in recent years, and consequently, there has been increased exposure of ecosystems and human populations to these highly toxic compounds. The study and development of methodologies to detect these substances with greater sensitivity has become extremely relevant. This article describes, for the first time, the use of atomic force spectroscopy (AFS in the detection of enzyme-inhibiting herbicides. A nanobiosensor based on an atomic force microscopy (AFM tip functionalised with the acetolactate synthase (ALS enzyme was developed and characterised. The herbicide metsulfuron-methyl, an ALS inhibitor, was successfully detected through the acquisition of force curves using this biosensor. The adhesion force values were considerably higher when the biosensor was used. An increase of ~250% was achieved relative to the adhesion force using an unfunctionalised AFM tip. This considerable increase was the result of a specific interaction between the enzyme and the herbicide, which was primarily responsible for the efficiency of the nanobiosensor. These results indicate that this methodology is promising for the detection of herbicides, pesticides, and other environmental contaminants.

Characterization of Bitumen Micro-Mechanical Behaviors Using AFM, Phase Dynamics Theory and MD Simulation

Directory of Open Access Journals (Sweden)

Yue Hou

2017-02-01

Full Text Available Fundamental understanding of micro-mechanical behaviors in bitumen, including phase separation, micro-friction, micro-abrasion, etc., can help the pavement engineers better understand the bitumen mechanical performances at macroscale. Recent researches show that the microstructure evolution in bitumen will directly affect its surface structure and micro-mechanical performance. In this study, the bitumen microstructure and micro-mechanical behaviors are studied using Atomic Force Microscopy (AFM experiments, Phase Dynamics Theory and Molecular Dynamics (MD Simulation. The AFM experiment results show that different phase-structure will occur at the surface of the bitumen samples under certain thermodynamic conditions at microscale. The phenomenon can be explained using the phase dynamics theory, where the effects of stability parameter and temperature on bitumen microstructure and micro-mechanical behavior are studied combined with MD Simulation. Simulation results show that the saturates phase, in contrast to the naphthene aromatics phase, plays a major role in bitumen micro-mechanical behavior. A high stress zone occurs at the interface between the saturates phase and the naphthene aromatics phase, which may form discontinuities that further affect the bitumen frictional performance.

Characterization of Bitumen Micro-Mechanical Behaviors Using AFM, Phase Dynamics Theory and MD Simulation.

Science.gov (United States)

Hou, Yue; Wang, Linbing; Wang, Dawei; Guo, Meng; Liu, Pengfei; Yu, Jianxin

2017-02-21

Fundamental understanding of micro-mechanical behaviors in bitumen, including phase separation, micro-friction, micro-abrasion, etc., can help the pavement engineers better understand the bitumen mechanical performances at macroscale. Recent researches show that the microstructure evolution in bitumen will directly affect its surface structure and micro-mechanical performance. In this study, the bitumen microstructure and micro-mechanical behaviors are studied using Atomic Force Microscopy (AFM) experiments, Phase Dynamics Theory and Molecular Dynamics (MD) Simulation. The AFM experiment results show that different phase-structure will occur at the surface of the bitumen samples under certain thermodynamic conditions at microscale. The phenomenon can be explained using the phase dynamics theory, where the effects of stability parameter and temperature on bitumen microstructure and micro-mechanical behavior are studied combined with MD Simulation. Simulation results show that the saturates phase, in contrast to the naphthene aromatics phase, plays a major role in bitumen micro-mechanical behavior. A high stress zone occurs at the interface between the saturates phase and the naphthene aromatics phase, which may form discontinuities that further affect the bitumen frictional performance.

U.S. Army Training and Testing Area Carrying Capacity (ATTACC) for Munitions (AFM)

Science.gov (United States)

2006-11-01

Army Training Support Center USDA United States Department of Agriculture USGS United States Geological Survey USLE Universal Soil Loss Equation...Range condition is a function of climate, soil , and hydrology. The munitions impact, constituent load, and range condition are modeled using AFM...For ArcGIS v2 to attain expected concentrations of munitions constituents and corresponding risk due to exposure through soil - and water-related

Limitations for qualitative and quantitative neutron activation analysis using reactor neutrons

International Nuclear Information System (INIS)

El-Abbady, W.H.; El-Tanahy, Z.H.; El-Hagg, A.A.; Hassan, A.M.

1999-01-01

In this work, the most important limitations for qualitative and quantitative analysis using reactor neutrons for activation are reviewed. Each limitation is discussed using different examples of activated samples. Photopeak estimation, nuclear reactions interference and neutron flux measurements are taken into consideration. Solutions for high accuracy evaluation in neutron activation analysis applications are given. (author)

Simulated structure and imaging of NTCDI on Si(1 1 1)-7 × 7 : a combined STM, NC-AFM and DFT study

Science.gov (United States)

Jarvis, S. P.; Sweetman, A. M.; Lekkas, I.; Champness, N. R.; Kantorovich, L.; Moriarty, P.

2015-02-01

The adsorption of naphthalene tetracarboxylic diimide (NTCDI) on Si(1 1 1)-7 × 7 is investigated through a combination of scanning tunnelling microscopy (STM), noncontact atomic force microscopy (NC-AFM) and density functional theory (DFT) calculations. We show that NTCDI adopts multiple planar adsorption geometries on the Si(1 1 1)-7 × 7 surface which can be imaged with intramolecular bond resolution using NC-AFM. DFT calculations reveal adsorption is dominated by covalent bond formation between the molecular oxygen atoms and the surface silicon adatoms. The chemisorption of the molecule is found to induce subtle distortions to the molecular structure, which are observed in NC-AFM images.

Spin dynamics and quantum tunneling in Fe8 nanomagnet and in AFM rings by NMR

Science.gov (United States)

Baek, Seung-Ho

In this thesis, our main interest has been to investigate the spin dynamics and quantum tunneling in single molecule magnets (SMMs). For this we have selected two different classes of SMMs: a ferromagnetic total high spin S = 10 cluster Fe8 and antiferromagnetic (AFM) ring-type clusters. For Fe8, our efforts have been devoted to the investigation of the quantum tunneling of magnetization in the very low temperature region. The most remarkable experimental finding in Fe8 is that the nuclear spin-lattice relaxation rate (1/T1) at low temperatures takes place via strong collision mechanism, and thus it allows to measure directly the tunneling rate vs. T and H for the first time. For AFM rings, we have shown that 1/T1 probes the thermal fluctuations of the magnetization in the intermediate temperature range. We find that the fluctuations are dominated by a single characteristic frequency which has a power-law T-dependence indicative of fluctuations due to electron-acoustic phonon interactions.

Spin Dynamics and Quantum Tunneling in Fe8 Nanomagnet and in AFM Rings by NMR

International Nuclear Information System (INIS)

Seung-Ho-Baek

2004-01-01

In this thesis, our main interest has been to investigate the spin dynamics and quantum tunneling in single molecule magnets (SMMs), For this we have selected two different classes of SMMs: a ferrimagnetic total high spin S = 10 cluster Fe8 and antiferromagnetic (AFM) ring-type clusters. For Fe8, our efforts have been devoted to the investigation of the quantum tunneling of magnetization in the very low temperature region. The most remarkable experimental finding in Fe8 is that the nuclear spin-lattice relaxation rate (1/T l ) at low temperatures takes place via strong collision mechanism, and thus it allows to measure directly the tunneling rate vs T and H for the first time. For AFM rings, we have shown that 1/T l probes the thermal fluctuations of the magnetization in the intermediate temperature range. We find that the fluctuations are dominated by a single characteristic frequency which has a power law T-dependence indicative of fluctuations due to electron-acoustic phonon interactions

Fast and accurate: high-speed metrological large-range AFM for surface and nanometrology

Science.gov (United States)

Dai, Gaoliang; Koenders, Ludger; Fluegge, Jens; Hemmleb, Matthias

2018-05-01

Low measurement speed remains a major shortcoming of the scanning probe microscopic technique. It not only leads to a low measurement throughput, but a significant measurement drift over the long measurement time needed (up to hours or even days). To overcome this challenge, PTB, the national metrology institute of Germany, has developed a high-speed metrological large-range atomic force microscope (HS Met. LR-AFM) capable of measuring speeds up to 1 mm s‑1. This paper has introduced the design concept in detail. After modelling scanning probe microscopic measurements, our results suggest that the signal spectrum of the surface to be measured is the spatial spectrum of the surface scaled by the scanning speed. The higher the scanning speed , the broader the spectrum to be measured. To realise an accurate HS Met. LR-AFM, our solution is to combine different stages/sensors synchronously in measurements, which provide a much larger spectrum area for high-speed measurement capability. Two application examples have been demonstrated. The first is a new concept called reference areal surface metrology. Using the developed HS Met. LR-AFM, surfaces are measured accurately and traceably at a speed of 500 µm s‑1 and the results are applied as a reference 3D data map of the surfaces. By correlating the reference 3D data sets and 3D data sets of tools under calibration, which are measured at the same surface, it has the potential to comprehensively characterise the tools, for instance, the spectrum properties of the tools. The investigation results of two commercial confocal microscopes are demonstrated, indicating very promising results. The second example is the calibration of a kind of 3D nano standard, which has spatially distributed landmarks, i.e. special unique features defined by 3D-coordinates. Experimental investigations confirmed that the calibration accuracy is maintained at a measurement speed of 100 µm s‑1, which improves the calibration efficiency by a

Dual frequency modulation with two cantilevers in series: a possible means to rapidly acquire tip–sample interaction force curves with dynamic AFM

International Nuclear Information System (INIS)

Solares, Santiago D; Chawla, Gaurav

2008-01-01

One common application of atomic force microscopy (AFM) is the acquisition of tip–sample interaction force curves. However, this can be a slow process when the user is interested in studying non-uniform samples, because existing contact- and dynamic-mode methods require that the measurement be performed at one fixed surface point at a time. This paper proposes an AFM method based on dual frequency modulation using two cantilevers in series, which could be used to measure the tip–sample interaction force curves and topography of the entire sample with a single surface scan, in a time that is comparable to the time needed to collect a topographic image with current AFM imaging modes. Numerical simulation results are provided along with recommended parameters to characterize tip–sample interactions resembling those of conventional silicon tips and carbon nanotube tips tapping on silicon surfaces

Program for the quantitative and qualitative analysis of

International Nuclear Information System (INIS)

Tepelea, V.; Purice, E.; Dan, R.; Calcev, G.; Domnisan, M.; Galis, V.; Teodosiu, G.; Debert, C.; Mocanu, N.; Nastase, M.

1985-01-01

A computer code for processing of data from neutron activation analysis is described. The code is capable of qualitative and quantitative analysis of regular spectra from neutron irradiated samples, measured by a Ge(li) detector. Multichannel analysers with 1024 channels, such as TN 1705 or a Romanian made MCA 79, and an ITC interface can be used. The code is implemented on FELIX M118 and FELIX M216 microcomputers. Spectrum processing is performed off line, after storing the data on a floppy disk. The background is assumed to be a polynomial of first, second or third degree. Qualitative analysis is performed by recursive least square, Gaussian curve fitting. The elements are identified using a polynomial relation between energy and channel, obtained by calibration with a standard sample

Multivariate analysis of quantitative traits can effectively classify rapeseed germplasm

Directory of Open Access Journals (Sweden)

Jankulovska Mirjana

2014-01-01

Full Text Available In this study, the use of different multivariate approaches to classify rapeseed genotypes based on quantitative traits has been presented. Tree regression analysis, PCA analysis and two-way cluster analysis were applied in order todescribe and understand the extent of genetic variability in spring rapeseed genotype by trait data. The traits which highly influenced seed and oil yield in rapeseed were successfully identified by the tree regression analysis. Principal predictor for both response variables was number of pods per plant (NP. NP and 1000 seed weight could help in the selection of high yielding genotypes. High values for both traits and oil content could lead to high oil yielding genotypes. These traits may serve as indirect selection criteria and can lead to improvement of seed and oil yield in rapeseed. Quantitative traits that explained most of the variability in the studied germplasm were classified using principal component analysis. In this data set, five PCs were identified, out of which the first three PCs explained 63% of the total variance. It helped in facilitating the choice of variables based on which the genotypes’ clustering could be performed. The two-way cluster analysissimultaneously clustered genotypes and quantitative traits. The final number of clusters was determined using bootstrapping technique. This approach provided clear overview on the variability of the analyzed genotypes. The genotypes that have similar performance regarding the traits included in this study can be easily detected on the heatmap. Genotypes grouped in the clusters 1 and 8 had high values for seed and oil yield, and relatively short vegetative growth duration period and those in cluster 9, combined moderate to low values for vegetative growth duration and moderate to high seed and oil yield. These genotypes should be further exploited and implemented in the rapeseed breeding program. The combined application of these multivariate methods

Quantitative method of X-ray diffraction phase analysis of building materials

International Nuclear Information System (INIS)

Czuba, J.; Dziedzic, A.

1978-01-01

Quantitative method of X-ray diffraction phase analysis of building materials, with use of internal standard, has been presented. The errors committed by determining the content of particular phases have been also given. (author)

Microstructure aspects of radiation-cured networks: Cationically polymerized aromatic epoxy resins

Science.gov (United States)

Kowandy, Christelle; Ranoux, Guillaume; Walo, Marta; Vissouvanadin, Bertrand; Teyssedre, Gilbert; Laurent, Christian; Berquand, Alexandre; Molinari, Michaël; Coqueret, Xavier

2018-02-01

The thermo-mechanical properties and nanostructural features of epoxy aromatic resins cationically cured by UV-visible or electron beam radiation have been studied by FT-NIR spectroscopy, dynamic mechanical analysis (DMA), dielectric spectroscopy (DS), and atomic force microscopy (AFM). The influence of formulation (nature and content of onium salt) and of curing parameters (doses, thermal treatment) on the thermophysical have been investigated. The presence of several relaxation domains observed by DMA and DS analysis confirms the presence of heterogeneities in the cured materials. Network formation is described by the percolation of glassy nanoclusters which are evidenced by AFM analyses. AFM probing by quantitative nanomechanical measurements confirms the gradual build-up of the local Young's modulus in good agreement with the macroscopic value.

Application of magnetic carriers to two examples of quantitative cell analysis

Energy Technology Data Exchange (ETDEWEB)

Zhou, Chen; Qian, Zhixi; Choi, Young Suk; David, Allan E. [Department of Chemical Engineering, 212 Ross Hall, Auburn University, Auburn, AL 36849 (United States); Todd, Paul, E-mail: pwtodd@hotmail.com [Techshot, Inc., 7200 Highway 150, Greenville, IN 47124 (United States); Hanley, Thomas R. [Department of Chemical Engineering, 212 Ross Hall, Auburn University, Auburn, AL 36849 (United States)

2017-04-01

The use of magnetophoretic mobility as a surrogate for fluorescence intensity in quantitative cell analysis was investigated. The objectives of quantitative fluorescence flow cytometry include establishing a level of labeling for the setting of parameters in fluorescence activated cell sorters (FACS) and the determination of levels of uptake of fluorescently labeled substrates by living cells. Likewise, the objectives of quantitative magnetic cytometry include establishing a level of labeling for the setting of parameters in flowing magnetic cell sorters and the determination of levels of uptake of magnetically labeled substrates by living cells. The magnetic counterpart to fluorescence intensity is magnetophoretic mobility, defined as the velocity imparted to a suspended cell per unit of magnetic ponderomotive force. A commercial velocimeter available for making this measurement was used to demonstrate both applications. Cultured Gallus lymphoma cells were immunolabeled with commercial magnetic beads and shown to have adequate magnetophoretic mobility to be separated by a novel flowing magnetic separator. Phagocytosis of starch nanoparticles having magnetic cores by cultured Chinese hamster ovary cells, a CHO line, was quantified on the basis of magnetophoretic mobility. - Highlights: • Commercial particle tracking velocimetry measures magnetophoretic mobility of labeled cells. • Magnetically labeled tumor cells were shown to have adequate mobility for capture in a specific sorter. • The kinetics of nonspecific endocytosis of magnetic nanomaterials by CHO cells was characterized. • Magnetic labeling of cells can be used like fluorescence flow cytometry for quantitative cell analysis.

Quantitative 3D analysis of bone in hip osteoarthritis using clinical computed tomography.

Science.gov (United States)

Turmezei, Tom D; Treece, Graham M; Gee, Andrew H; Fotiadou, Anastasia F; Poole, Kenneth E S

2016-07-01

To assess the relationship between proximal femoral cortical bone thickness and radiological hip osteoarthritis using quantitative 3D analysis of clinical computed tomography (CT) data. Image analysis was performed on clinical CT imaging data from 203 female volunteers with a technique called cortical bone mapping (CBM). Colour thickness maps were created for each proximal femur. Statistical parametric mapping was performed to identify statistically significant differences in cortical bone thickness that corresponded with the severity of radiological hip osteoarthritis. Kellgren and Lawrence (K&L) grade, minimum joint space width (JSW) and a novel CT-based osteophyte score were also blindly assessed from the CT data. For each increase in K&L grade, cortical thickness increased by up to 25 % in distinct areas of the superolateral femoral head-neck junction and superior subchondral bone plate. For increasing severity of CT osteophytes, the increase in cortical thickness was more circumferential, involving a wider portion of the head-neck junction, with up to a 7 % increase in cortical thickness per increment in score. Results were not significant for minimum JSW. These findings indicate that quantitative 3D analysis of the proximal femur can identify changes in cortical bone thickness relevant to structural hip osteoarthritis. • CT is being increasingly used to assess bony involvement in osteoarthritis • CBM provides accurate and reliable quantitative analysis of cortical bone thickness • Cortical bone is thicker at the superior femoral head-neck with worse osteoarthritis • Regions of increased thickness co-locate with impingement and osteophyte formation • Quantitative 3D bone analysis could enable clinical disease prediction and therapy development.

[Quantitative Analysis of Heavy Metals in Water with LIBS Based on Signal-to-Background Ratio].

Science.gov (United States)

Hu, Li; Zhao, Nan-jing; Liu, Wen-qing; Fang, Li; Zhang, Da-hai; Wang, Yin; Meng, De Shuo; Yu, Yang; Ma, Ming-jun

2015-07-01

There are many influence factors in the precision and accuracy of the quantitative analysis with LIBS technology. According to approximately the same characteristics trend of background spectrum and characteristic spectrum along with the change of temperature through in-depth analysis, signal-to-background ratio (S/B) measurement and regression analysis could compensate the spectral line intensity changes caused by system parameters such as laser power, spectral efficiency of receiving. Because the measurement dates were limited and nonlinear, we used support vector machine (SVM) for regression algorithm. The experimental results showed that the method could improve the stability and the accuracy of quantitative analysis of LIBS, and the relative standard deviation and average relative error of test set respectively were 4.7% and 9.5%. Data fitting method based on signal-to-background ratio(S/B) is Less susceptible to matrix elements and background spectrum etc, and provides data processing reference for real-time online LIBS quantitative analysis technology.

Correlative SEM SERS for quantitative analysis of dimer nanoparticles.

Science.gov (United States)

Timmermans, F J; Lenferink, A T M; van Wolferen, H A G M; Otto, C

2016-11-14

A Raman microscope integrated with a scanning electron microscope was used to investigate plasmonic structures by correlative SEM-SERS analysis. The integrated Raman-SEM microscope combines high-resolution electron microscopy information with SERS signal enhancement from selected nanostructures with adsorbed Raman reporter molecules. Correlative analysis is performed for dimers of two gold nanospheres. Dimers were selected on the basis of SEM images from multi aggregate samples. The effect of the orientation of the dimer with respect to the polarization state of the laser light and the effect of the particle gap size on the Raman signal intensity is observed. Additionally, calculations are performed to simulate the electric near field enhancement. These simulations are based on the morphologies observed by electron microscopy. In this way the experiments are compared with the enhancement factor calculated with near field simulations and are subsequently used to quantify the SERS enhancement factor. Large differences between experimentally observed and calculated enhancement factors are regularly detected, a phenomenon caused by nanoscale differences between the real and 'simplified' simulated structures. Quantitative SERS experiments reveal the structure induced enhancement factor, ranging from ∼200 to ∼20 000, averaged over the full nanostructure surface. The results demonstrate correlative Raman-SEM microscopy for the quantitative analysis of plasmonic particles and structures, thus enabling a new analytical method in the field of SERS and plasmonics.

Quantitative analysis method for niobium in lead zirconate titanate

International Nuclear Information System (INIS)

Hara, Hideo; Hashimoto, Toshio

1986-01-01

Lead zirconate titanate (PZT) is a strong dielectric ceramic having piezoelectric and pyroelectric properties, and is used most as a piezoelectric material. Also it is a main component of lead lanthanum zirconate titanate (PLZT), which is a typical electrical-optical conversion element. Since these have been developed, the various electronic parts utilizing the piezoelectric characteristics have been put in practical use. The characteristics can be set up by changing the composition of PZT and the kinds and amount of additives. Among the additives, niobium has the action to make metallic ion vacancy in crystals, and by the formation of this vacancy, to ease the movement of domain walls in crystal grains, and to increase resistivity. Accordingly, it is necessary to accurately determine the niobium content for the research and development, quality control and process control. The quantitative analysis methods for niobium used so far have respective demerits, therefore, the authors examined the quantitative analysis of niobium in PZT by using an inductively coupled plasma emission spectro-analysis apparatus which has remarkably developed recently. As the result, the method of dissolving a specimen with hydrochloric acid and hydrofluoric acid, and masking unstable lead with ethylene diamine tetraacetic acid 2 sodium and fluoride ions with boric acid was established. The apparatus, reagents, the experiment and the results are reported. (Kako, I.)

Quality Assessments of Long-Term Quantitative Proteomic Analysis of Breast Cancer Xenograft Tissues

Energy Technology Data Exchange (ETDEWEB)

Zhou, Jian-Ying; Chen, Lijun; Zhang, Bai; Tian, Yuan; Liu, Tao; Thomas, Stefani N.; Chen, Li; Schnaubelt, Michael; Boja, Emily; Hiltket, Tara; Kinsinger, Christopher; Rodriguez, Henry; Davies, Sherri; Li, Shunqiang; Snider, Jacqueline E.; Erdmann-Gilmore, Petra; Tabb, David L.; Townsend, Reid; Ellis, Matthew; Rodland, Karin D.; Smith, Richard D.; Carr, Steven A.; Zhang, Zhen; Chan, Daniel W.; Zhang, Hui

2017-09-21

The identification of protein biomarkers requires large-scale analysis of human specimens to achieve statistical significance. In this study, we evaluated the long-term reproducibility of an iTRAQ (isobaric tags for relative and absolute quantification) based quantitative proteomics strategy using one channel for universal normalization across all samples. A total of 307 liquid chromatography tandem mass spectrometric (LC-MS/MS) analyses were completed, generating 107 one-dimensional (1D) LC-MS/MS datasets and 8 offline two-dimensional (2D) LC-MS/MS datasets (25 fractions for each set) for human-in-mouse breast cancer xenograft tissues representative of basal and luminal subtypes. Such large-scale studies require the implementation of robust metrics to assess the contributions of technical and biological variability in the qualitative and quantitative data. Accordingly, we developed a quantification confidence score based on the quality of each peptide-spectrum match (PSM) to remove quantification outliers from each analysis. After combining confidence score filtering and statistical analysis, reproducible protein identification and quantitative results were achieved from LC-MS/MS datasets collected over a 16 month period.

Absorption correction factor in X-ray fluorescent quantitative analysis

International Nuclear Information System (INIS)

Pimjun, S.

1994-01-01

An experiment on absorption correction factor in X-ray fluorescent quantitative analysis were carried out. Standard samples were prepared from the mixture of Fe 2 O 3 and tapioca flour at various concentration of Fe 2 O 3 ranging from 5% to 25%. Unknown samples were kaolin containing 3.5% to-50% of Fe 2 O 3 Kaolin samples were diluted with tapioca flour in order to reduce the absorption of FeK α and make them easy to prepare. Pressed samples with 0.150 /cm 2 and 2.76 cm in diameter, were used in the experiment. Absorption correction factor is related to total mass absorption coefficient (χ) which varied with sample composition. In known sample, χ can be calculated by conveniently the formula. However in unknown sample, χ can be determined by Emission-Transmission method. It was found that the relationship between corrected FeK α intensity and contents of Fe 2 O 3 in these samples was linear. This result indicate that this correction factor can be used to adjust the accuracy of X-ray intensity. Therefore, this correction factor is essential in quantitative analysis of elements comprising in any sample by X-ray fluorescent technique

Quantitative analysis of the secretion of the MCP family of chemokines by muscle cells

DEFF Research Database (Denmark)

Henningsen, Jeanette; Pedersen, Bente Klarlund; Kratchmarova, Irina

2011-01-01

by Amino acids in Cell culture (SILAC) method for quantitative analysis resulted in the identification and generation of quantitative profiles of 59 growth factors and cytokines, including 9 classical chemokines. The members of the CC chemokine family of proteins such as monocyte chemotactic proteins 1, 2...

Qualitative and quantitative reliability analysis of safety systems

International Nuclear Information System (INIS)

Karimi, R.; Rasmussen, N.; Wolf, L.

1980-05-01

A code has been developed for the comprehensive analysis of a fault tree. The code designated UNRAC (UNReliability Analysis Code) calculates the following characteristics of an input fault tree: (1) minimal cut sets; (2) top event unavailability as point estimate and/or in time dependent form; (3) quantitative importance of each component involved; and, (4) error bound on the top event unavailability. UNRAC can analyze fault trees, with any kind of gates (EOR, NAND, NOR, AND, OR), up to a maximum of 250 components and/or gates. The code is benchmarked against WAMCUT, MODCUT, KITT, BIT-FRANTIC, and PL-MODT. The results showed that UNRAC produces results more consistent with the KITT results than either BIT-FRANTIC or PL-MODT. Overall it is demonstrated that UNRAC is an efficient easy-to-use code and has the advantage of being able to do a complete fault tree analysis with this single code. Applications of fault tree analysis to safety studies of nuclear reactors are considered

Quantitative analysis of regional myocardial performance in coronary artery disease

Science.gov (United States)

Stewart, D. K.; Dodge, H. T.; Frimer, M.

1975-01-01

Findings from a group of subjects with significant coronary artery stenosis are given. A group of controls determined by use of a quantitative method for the study of regional myocardial performance based on the frame-by-frame analysis of biplane left ventricular angiograms are presented. Particular emphasis was placed upon the analysis of wall motion in terms of normalized segment dimensions, timing and velocity of contraction. The results were compared with the method of subjective assessment used clinically.

Visualization and quantitative analysis of the CSF pulsatile flow with cine MR phase imaging

International Nuclear Information System (INIS)

Katayama, Shinji; Itoh, Takahiko; Kinugasa, Kazushi; Asari, Shoji; Nishimoto, Akira; Tsuchida, Shohei; Ono, Atsushi; Ikezaki, Yoshikazu; Yoshitome, Eiji.

1991-01-01

The visualization and the quantitative analysis of the CSF pulsatile flow were performed on ten healthy volunteers with cine MR phase imaging, a combination of the phase-contrast technique and the cardiac-gating technique. The velocities appropriate for the visualization and the quantitative analysis of the CSF pulsatile flow were from 6.0 cm/sec to 15.0 cm/sec. The applicability of this method for the quantitative analysis was proven with a steady-flow phantom. Phase images clearly demonstrated a to-and-fro motion of the CSF flow in the anterior subarachnoid space and in the posterior subarachnoid space. The flow pattern of CSF on healthy volunteers depends on the cardiac cycle. In the anterior subarachnoid space, the cephalic CSF flow continued until a 70-msec delay after the R-wave of the ECG and then reversed to caudal. At 130-190 msec, the caudal CSF flow reached its maximum velocity; thereafter it reversed again to cephalic. The same turn appeared following the phase, but then the amplitude decreased. The cephalic peaked at 370-430 msec, while the caudal peaked at 490-550 msec. The flow pattern of the CSF flow in the posterior subarachnoid space was almost identical to that in the anterior subarachnoid space. Cine MR phase imaging is thus useful for the visualization and the quantitative analysis of the CSF pulsative flow. (author)

Evaluation of elastic properties of DLC layers using resonant ultrasound spectroscopy and AFM nanoindentation

Czech Academy of Sciences Publication Activity Database

Kocourek, Tomáš; Růžek, Michal; Landa, Michal; Jelínek, Miroslav; Mikšovský, Jan; Kopeček, Jaromír

2011-01-01

Roč. 205, č. 2 (2011), S67-S70 ISSN 0257-8972 R&D Projects: GA ČR(CZ) GA101/09/0702 Institutional research plan: CEZ:AV0Z10100522; CEZ:AV0Z20760514 Keywords : RUS-resonant ultrasound spectroscopy * PLD * diamond-like carbon * elastic properties * AFM nanoindentation Subject RIV: BH - Optics, Masers, Lasers Impact factor: 1.867, year: 2011

Variable selection based near infrared spectroscopy quantitative and qualitative analysis on wheat wet gluten

Science.gov (United States)

Lü, Chengxu; Jiang, Xunpeng; Zhou, Xingfan; Zhang, Yinqiao; Zhang, Naiqian; Wei, Chongfeng; Mao, Wenhua

2017-10-01

Wet gluten is a useful quality indicator for wheat, and short wave near infrared spectroscopy (NIRS) is a high performance technique with the advantage of economic rapid and nondestructive test. To study the feasibility of short wave NIRS analyzing wet gluten directly from wheat seed, 54 representative wheat seed samples were collected and scanned by spectrometer. 8 spectral pretreatment method and genetic algorithm (GA) variable selection method were used to optimize analysis. Both quantitative and qualitative model of wet gluten were built by partial least squares regression and discriminate analysis. For quantitative analysis, normalization is the optimized pretreatment method, 17 wet gluten sensitive variables are selected by GA, and GA model performs a better result than that of all variable model, with R2V=0.88, and RMSEV=1.47. For qualitative analysis, automatic weighted least squares baseline is the optimized pretreatment method, all variable models perform better results than those of GA models. The correct classification rates of 3 class of 30% wet gluten content are 95.45, 84.52, and 90.00%, respectively. The short wave NIRS technique shows potential for both quantitative and qualitative analysis of wet gluten for wheat seed.

Scientific aspects of urolithiasis: quantitative stone analysis and crystallization experiments

International Nuclear Information System (INIS)

Wandt, M.A.E.

1986-03-01

The theory, development and results of three quantitative analytical procedures are described and the crystallization experiments in a rotary evaporator are presented. Of the different methods of quantitative X-ray powder diffraction analyses, the 'internal standard method' and a microanalytical technique were identified as the two most useful procedures for the quantitative analysis of urinary calculi. 'Reference intensity ratios' for 6 major stone phases were determined and were used in the analysis of 20 calculi by the 'internal standard method'. Inductively coupled plasma atomic emission spectroscopic (ICP-AES) methods were also investigated, developed and used in this study. Various procedures for the digestion of calculi were tested and a mixture of HNO 3 and HC1O 4 was eventually found to be the most successful. The major elements Ca, Mg, and P in 41 calculi were determined. For the determination of trace elements, a new microwave-assisted digestion procedure was developed and used for the digestion of 100 calculi. Fluoride concentrations in two stone collections were determined using a fluoride-ion sensitive electrode and the HNO 3 /HC1O 4 digestion prodecure used for the ICP study. A series of crystallization experiments involving a standard reference artificial urine was carried out in a rotary evaporator. The effect of pH and urine composition was studied by varying the former and by including uric acid, urea, creatinine, MgO, methylene blue, chondroitin sulphate A, and fluoride in the reference solution. Crystals formed in these experiments were subjected to qualitative and semi-quantitative X-ray powder diffraction analyses. Scanning electron microscopy of several deposits was also carried out. Similar deposits to those observed in calculi were obtained with the fast evaporator. The results presented suggest that this system provides a simple, yet very useful means for studying the crystallization characteristics of urine solutions

Iron in carbonate containing AFm phases

International Nuclear Information System (INIS)

Dilnesa, B.Z.; Lothenbach, B.; Le Saout, G.; Renaudin, G.; Mesbah, A.; Filinchuk, Y.; Wichser, A.; Wieland, E.

2011-01-01

One of the AFm phases in hydrated Portland cement is Ca 3 (Al x Fe 2 - x )O 6 .CaCO 3 .nH 2 O. It is based on hexagonal and platey structural elements and the interlayer structure incorporates CO 3 2- . The solid phases were experimentally synthesized and characterized by different techniques including X-ray techniques (XRD and EXAFS) and vibrational spectroscopy techniques (IR, Raman). Fe-monocarbonate (Fe-Mc) and Al-monocarbonate (Al-Mc) were found to be stable up to 50 o C, while Fe-hemicarbonate (Fe-Hc) was unstable with respect to Fe-Mc in the presence of calcite. Fe-Mc has a rhombohedral R3-barc symmetry which is different from the triclinic of the Al analogue. Both XRD and thermodynamic modelling of the liquid compositions indicated that Al-Mc and the Fe-Mc phases do not form solid solution. The solubility products were calculated experimentally at 20 o C and 50 o C. Under standards condition the solubility products and other thermodynamic parameters were estimated using temperature-solubility product extrapolation and found to be logK S0 (Fe-Mc) = -34.59 ± 0.50, logK S0 (Fe-Hc) = -30.83 ± 0.50 and logK S0 (Al-Mc) = -31.32 ± 0.50.

Quantitative analysis of food and feed samples with droplet digital PCR.

Directory of Open Access Journals (Sweden)

Dany Morisset

Full Text Available In this study, the applicability of droplet digital PCR (ddPCR for routine analysis in food and feed samples was demonstrated with the quantification of genetically modified organisms (GMOs. Real-time quantitative polymerase chain reaction (qPCR is currently used for quantitative molecular analysis of the presence of GMOs in products. However, its use is limited for detecting and quantifying very small numbers of DNA targets, as in some complex food and feed matrices. Using ddPCR duplex assay, we have measured the absolute numbers of MON810 transgene and hmg maize reference gene copies in DNA samples. Key performance parameters of the assay were determined. The ddPCR system is shown to offer precise absolute and relative quantification of targets, without the need for calibration curves. The sensitivity (five target DNA copies of the ddPCR assay compares well with those of individual qPCR assays and of the chamber digital PCR (cdPCR approach. It offers a dynamic range over four orders of magnitude, greater than that of cdPCR. Moreover, when compared to qPCR, the ddPCR assay showed better repeatability at low target concentrations and a greater tolerance to inhibitors. Finally, ddPCR throughput and cost are advantageous relative to those of qPCR for routine GMO quantification. It is thus concluded that ddPCR technology can be applied for routine quantification of GMOs, or any other domain where quantitative analysis of food and feed samples is needed.