A radiographic scanning technique for cores

USGS Publications Warehouse

Hill, G.W.; Dorsey, M.E.; Woods, J.C.; Miller, R.J.

1979-01-01

A radiographic scanning technique (RST) can produce single continuous radiographs of cores or core sections up to 1.5 m long and up to 30 cm wide. Changing a portable industrial X-ray unit from the normal still-shot mode to a scanning mode requires simple, inexpensive, easily constructed, and highly durable equipment. Additional components include a conveyor system, antiscatter cylinder-diaphragm, adjustable sample platform, developing tanks, and a contact printer. Complete cores, half cores, sample slabs or peels may be scanned. Converting the X-ray unit from one mode to another is easy and can be accomplished without the use of special tools. RST provides the investigator with a convenient, continuous, high quality radiograph, saves time and money, and decreases the number of times cores have to be handled. ?? 1979.

Robotic inspection of fiber reinforced composites using phased array UT

NASA Astrophysics Data System (ADS)

Stetson, Jeffrey T.; De Odorico, Walter

2014-02-01

Ultrasound is the current NDE method of choice to inspect large fiber reinforced airframe structures. Over the last 15 years Cartesian based scanning machines using conventional ultrasound techniques have been employed by all airframe OEMs and their top tier suppliers to perform these inspections. Technical advances in both computing power and commercially available, multi-axis robots now facilitate a new generation of scanning machines. These machines use multiple end effector tools taking full advantage of phased array ultrasound technologies yielding substantial improvements in inspection quality and productivity. This paper outlines the general architecture for these new robotic scanning systems as well as details the variety of ultrasonic techniques available for use with them including advances such as wide area phased array scanning and sound field adaptation for non-flat, non-parallel surfaces.

Nondestructive Examination of Inside Surfaces of Small Holes in a Steel Structure Using a Laser Scan Technique

DTIC Science & Technology

2017-04-03

HOLES IN A STEEL STRUCTURE USING A LASER SCAN TECHNIQUE David Grasing Adam Foltz Ryan Hooke Venkataraman Swaminathan U.S. Army ARDEC...NUMBER 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 6. AUTHORS David Grasing, Adam Foltz, Ryan Hooke, and Venkataraman Swaminathan – U.S...PAGES 21 19a. NAME OF RESPONSIBLE PERSON Venkataraman Swaminathan a. REPORT U b. ABSTRACT U c. THIS PAGE U 19b. TELEPHONE NUMBER (Include

Sensing Applied Load and Damage Effects in Composites with Nondestructive Techniques

DTIC Science & Technology

2017-05-01

evaluation (NDE) techniques. Evaluation using piezoelectrically induced guided waves, acoustic emission, thermography, and X-ray imaging were compared...nondestructive inspection to further understanding of the material itself and the capabilities of various nondestructive evaluation (NDE) techniques...materials because of their inherent differences. NDE techniques exist that can evaluate composite structures for damage including C-Scan

Photomorphic analysis techniques: An interim spatial analysis using satellite remote sensor imagery and historical data

NASA Technical Reports Server (NTRS)

Keuper, H. R.; Peplies, R. W.; Gillooly, R. P.

1977-01-01

The use of machine scanning and/or computer-based techniques to provide greater objectivity in the photomorphic approach was investigated. Photomorphic analysis and its application in regional planning are discussed. Topics included: delineation of photomorphic regions; inadequacies of existing classification systems; tonal and textural characteristics and signature analysis techniques; pattern recognition and Fourier transform analysis; and optical experiments. A bibliography is included.

Investigating the Role of Global Histogram Equalization Technique for 99mTechnetium-Methylene diphosphonate Bone Scan Image Enhancement

PubMed Central

Pandey, Anil Kumar; Sharma, Param Dev; Dheer, Pankaj; Parida, Girish Kumar; Goyal, Harish; Patel, Chetan; Bal, Chandrashekhar; Kumar, Rakesh

2017-01-01

Purpose of the Study: 99mTechnetium-methylene diphosphonate (99mTc-MDP) bone scan images have limited number of counts per pixel, and hence, they have inferior image quality compared to X-rays. Theoretically, global histogram equalization (GHE) technique can improve the contrast of a given image though practical benefits of doing so have only limited acceptance. In this study, we have investigated the effect of GHE technique for 99mTc-MDP-bone scan images. Materials and Methods: A set of 89 low contrast 99mTc-MDP whole-body bone scan images were included in this study. These images were acquired with parallel hole collimation on Symbia E gamma camera. The images were then processed with histogram equalization technique. The image quality of input and processed images were reviewed by two nuclear medicine physicians on a 5-point scale where score of 1 is for very poor and 5 is for the best image quality. A statistical test was applied to find the significance of difference between the mean scores assigned to input and processed images. Results: This technique improves the contrast of the images; however, oversaturation was noticed in the processed images. Student's t-test was applied, and a statistically significant difference in the input and processed image quality was found at P < 0.001 (with α = 0.05). However, further improvement in image quality is needed as per requirements of nuclear medicine physicians. Conclusion: GHE techniques can be used on low contrast bone scan images. In some of the cases, a histogram equalization technique in combination with some other postprocessing technique is useful. PMID:29142344

Recent Advances in X-ray Cone-beam Computed Laminography.

PubMed

O'Brien, Neil S; Boardman, Richard P; Sinclair, Ian; Blumensath, Thomas

2016-10-06

X-ray computed tomography is an established volume imaging technique used routinely in medical diagnosis, industrial non-destructive testing, and a wide range of scientific fields. Traditionally, computed tomography uses scanning geometries with a single axis of rotation together with reconstruction algorithms specifically designed for this setup. Recently there has however been increasing interest in more complex scanning geometries. These include so called X-ray computed laminography systems capable of imaging specimens with large lateral dimensions or large aspect ratios, neither of which are well suited to conventional CT scanning procedures. Developments throughout this field have thus been rapid, including the introduction of novel system trajectories, the application and refinement of various reconstruction methods, and the use of recently developed computational hardware and software techniques to accelerate reconstruction times. Here we examine the advances made in the last several years and consider their impact on the state of the art.

Applications of surface analytical techniques in Earth Sciences

NASA Astrophysics Data System (ADS)

Qian, Gujie; Li, Yubiao; Gerson, Andrea R.

2015-03-01

This review covers a wide range of surface analytical techniques: X-ray photoelectron spectroscopy (XPS), scanning photoelectron microscopy (SPEM), photoemission electron microscopy (PEEM), dynamic and static secondary ion mass spectroscopy (SIMS), electron backscatter diffraction (EBSD), atomic force microscopy (AFM). Others that are relatively less widely used but are also important to the Earth Sciences are also included: Auger electron spectroscopy (AES), low energy electron diffraction (LEED) and scanning tunnelling microscopy (STM). All these techniques probe only the very top sample surface layers (sub-nm to several tens of nm). In addition, we also present several other techniques i.e. Raman microspectroscopy, reflection infrared (IR) microspectroscopy and quantitative evaluation of minerals by scanning electron microscopy (QEMSCAN) that penetrate deeper into the sample, up to several μm, as all of them are fundamental analytical tools for the Earth Sciences. Grazing incidence synchrotron techniques, sensitive to surface measurements, are also briefly introduced at the end of this review. (Scanning) transmission electron microscopy (TEM/STEM) is a special case that can be applied to characterisation of mineralogical and geological sample surfaces. Since TEM/STEM is such an important technique for Earth Scientists, we have also included it to draw attention to the capability of TEM/STEM applied as a surface-equivalent tool. While this review presents most of the important techniques for the Earth Sciences, it is not an all-inclusive bibliography of those analytical techniques. Instead, for each technique that is discussed, we first give a very brief introduction about its principle and background, followed by a short section on approaches to sample preparation that are important for researchers to appreciate prior to the actual sample analysis. We then use examples from publications (and also some of our known unpublished results) within the Earth Sciences to show how each technique is applied and used to obtain specific information and to resolve real problems, which forms the central theme of this review. Although this review focuses on applications of these techniques to study mineralogical and geological samples, we also anticipate that researchers from other research areas such as Material and Environmental Sciences may benefit from this review.

Fetal brain volumetry through MRI volumetric reconstruction and segmentation

PubMed Central

Estroff, Judy A.; Barnewolt, Carol E.; Connolly, Susan A.; Warfield, Simon K.

2013-01-01

Purpose Fetal MRI volumetry is a useful technique but it is limited by a dependency upon motion-free scans, tedious manual segmentation, and spatial inaccuracy due to thick-slice scans. An image processing pipeline that addresses these limitations was developed and tested. Materials and methods The principal sequences acquired in fetal MRI clinical practice are multiple orthogonal single-shot fast spin echo scans. State-of-the-art image processing techniques were used for inter-slice motion correction and super-resolution reconstruction of high-resolution volumetric images from these scans. The reconstructed volume images were processed with intensity non-uniformity correction and the fetal brain extracted by using supervised automated segmentation. Results Reconstruction, segmentation and volumetry of the fetal brains for a cohort of twenty-five clinically acquired fetal MRI scans was done. Performance metrics for volume reconstruction, segmentation and volumetry were determined by comparing to manual tracings in five randomly chosen cases. Finally, analysis of the fetal brain and parenchymal volumes was performed based on the gestational age of the fetuses. Conclusion The image processing pipeline developed in this study enables volume rendering and accurate fetal brain volumetry by addressing the limitations of current volumetry techniques, which include dependency on motion-free scans, manual segmentation, and inaccurate thick-slice interpolation. PMID:20625848

Bone scan findings in hypervitaminosis D: case report. [/sup 99m/Tc tracer technique

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fogelman, I.; McKillop, J.H.; Cowden, E.A.

1977-12-01

Bone scans in three patients showed generalized symmetrical increased uptake of radiopharmaceutical by the skeleton and absent or faint kidney images. It is thought that these appearances may be attributable to excess vitamin D, and other possible contributing factors, including the presence of renal osteodystrophy, are discussed.

Comparing Scanning Modes for Youths with Cerebral Palsy. Final Report.

ERIC Educational Resources Information Center

Ottenbacher, Kenneth J.; Angelo, Jennifer

This study of 22 individuals (ages 13-20) with cerebral palsy investigated the use of scanning, an interface technique that allows access to assistive devices such as communication boards, electronic augmentative communication devices, and computers by using a pointer, either a finger or a cursor. This packet of information includes the findings…

Scanning angle Raman spectroscopy: Investigation of Raman scatter enhancement techniques for chemical analysis

DOE Office of Scientific and Technical Information (OSTI.GOV)

Meyer, Matthew W.

2013-01-01

This thesis outlines advancements in Raman scatter enhancement techniques by applying evanescent fields, standing-waves (waveguides) and surface enhancements to increase the generated mean square electric field, which is directly related to the intensity of Raman scattering. These techniques are accomplished by employing scanning angle Raman spectroscopy and surface enhanced Raman spectroscopy. A 1064 nm multichannel Raman spectrometer is discussed for chemical analysis of lignin. Extending dispersive multichannel Raman spectroscopy to 1064 nm reduces the fluorescence interference that can mask the weaker Raman scattering. Overall, these techniques help address the major obstacles in Raman spectroscopy for chemical analysis, which include themore » inherently weak Raman cross section and susceptibility to fluorescence interference.« less

2D biological representations with reduced speckle obtained from two perpendicular ultrasonic arrays.

PubMed

Rodriguez-Hernandez, Miguel A; Gomez-Sacristan, Angel; Sempere-Payá, Víctor M

2016-04-29

Ultrasound diagnosis is a widely used medical tool. Among the various ultrasound techniques, ultrasonic imaging is particularly relevant. This paper presents an improvement to a two-dimensional (2D) ultrasonic system using measurements taken from perpendicular planes, where digital signal processing techniques are used to combine one-dimensional (1D) A-scans were acquired by individual transducers in arrays located in perpendicular planes. An algorithm used to combine measurements is improved based on the wavelet transform, which includes a denoising step during the 2D representation generation process. The inclusion of this new denoising stage generates higher quality 2D representations with a reduced level of speckling. The paper includes different 2D representations obtained from noisy A-scans and compares the improvements obtained by including the denoising stage.

Elemental mapping of biological samples using a scanning proton microprobe

NASA Astrophysics Data System (ADS)

Watt, F.; Grime, G. W.

1988-03-01

Elemental mapping using a scanning proton microprobe (SPM) can be a powerful technique for probing trace elements in biology, allowing complex interfaces to be studied in detail, identifying contamination and artefacts present in the specimen, and in certain circumstances obtaining indirect chemical information. Examples used to illustrate the advantages of the technique include the elemental mapping of growing pollen tubes, honey bee brain section, a mouse macrophage cell, human liver section exhibiting primary biliary cirrhosis, and the attack by a mildew fungus on a pea leaf.

Creating A 3D urban model by terrestrial laser scanners and photogrammetry techniques: a case study on the historical peninsula of Istanbul

NASA Astrophysics Data System (ADS)

Ergun, Bahadir

2007-07-01

Today, terrestrial laser scanning has been a frequently used methodology for the documentation of historical buildings and cultural heritages. The historical peninsula region is the documentation of historical buildings and cover approximately 1500 ha. Terrestrial laser scanning and close range image photogrammetry techniques are integrated to each other to create a 3D urban model of Istanbul including the most important landmarks and the buildings reflecting the most brilliant areas of Byzantine and Ottoman Empires.

A low-cost three-dimensional laser surface scanning approach for defining body segment parameters.

PubMed

Pandis, Petros; Bull, Anthony Mj

2017-11-01

Body segment parameters are used in many different applications in ergonomics as well as in dynamic modelling of the musculoskeletal system. Body segment parameters can be defined using different methods, including techniques that involve time-consuming manual measurements of the human body, used in conjunction with models or equations. In this study, a scanning technique for measuring subject-specific body segment parameters in an easy, fast, accurate and low-cost way was developed and validated. The scanner can obtain the body segment parameters in a single scanning operation, which takes between 8 and 10 s. The results obtained with the system show a standard deviation of 2.5% in volumetric measurements of the upper limb of a mannequin and 3.1% difference between scanning volume and actual volume. Finally, the maximum mean error for the moment of inertia by scanning a standard-sized homogeneous object was 2.2%. This study shows that a low-cost system can provide quick and accurate subject-specific body segment parameter estimates.

The development of efficient coding for an electronic mail system

NASA Technical Reports Server (NTRS)

Rice, R. F.

1983-01-01

Techniques for efficiently representing scanned electronic documents were investigated. Major results include the definition and preliminary performance results of a Universal System for Efficient Electronic Mail (USEEM), offering a potential order of magnitude improvement over standard facsimile techniques for representing textual material.

Three Dimensional Cross-Sectional Properties From Bone Densitometry

NASA Technical Reports Server (NTRS)

Cleek, Tammy M.; Whalen, Robert T.; Dalton, Bonnie P. (Technical Monitor)

2001-01-01

Bone densitometry has previously been used to obtain cross-sectional properties of bone in a single scan plane. Using three non-coplanar scans, we have extended the method to obtain the principal area Moments of inertia and orientations of the principal axes at each cross-section along the length of the scan. Various 5 aluminum phantoms were used to examine scanner characteristics to develop the highest accuracy possible for in vitro non-invasive analysis of mass distribution. Factors considered included X-ray photon energy, initial scan orientation, the included angle of the 3 scans, and Imin/Imax ratios. Principal moments of inertia were accurate to within 3.1% and principal angles were within 1 deg. of the expected value for phantoms scanned with included angles of 60 deg. and 90 deg. at the higher X-ray photon energy. Low standard deviations in error also 10 indicate high precision of calculated measurements with these included angles. Accuracy and precision decreased slightly when the included angle was reduced to 30 deg. The method was then successfully applied to a pair of excised cadaveric tibiae. The accuracy and insensitivity of the algorithms to cross-sectional shape and changing isotropy (Imin/Imax) values when various included angles are used make this technique viable for future in vivo studies.

Scanning Mode Sensor for Detection of Flow Inhomogeneities

NASA Technical Reports Server (NTRS)

Adamovsky, Grigory (Inventor)

1998-01-01

A scanning mode sensor and method is provided for detection of flow inhomogeneities such as shock. The field of use of this invention is ground test control and engine control during supersonic flight. Prior art measuring techniques include interferometry. Schlieren, and shadowgraph techniques. These techniques. however, have problems with light dissipation. The present method and sensor utilizes a pencil beam of energy which is passed through a transparent aperture in a flow inlet in a time-sequential manner so as to alter the energy beam. The altered beam or its effects are processed and can be studied to reveal information about flow through the inlet which can in turn be used for engine control.

Scanning Mode Sensor for Detection of Flow Inhomogeneities

NASA Technical Reports Server (NTRS)

Adamovsky, Grigory (Inventor)

1996-01-01

A scanning mode sensor and method is provided for detection of flow inhomogeneities such as shock. The field of use of this invention is ground test control and engine control during supersonic flight. Prior art measuring techniques include interferometry, Schlieren, and shadowgraph techniques. These techniques, however, have problems with light dissipation. The present method and sensor utilizes a pencil beam of energy which is passed through a transparent aperture in a flow inlet in a time-sequential manner so as to alter the energy beam. The altered beam or its effects are processed and can be studied to reveal information about flow through the inlet which can in turn be used for engine control.

Sound Visualization and Holography

ERIC Educational Resources Information Center

Kock, Winston E.

1975-01-01

Describes liquid surface holograms including their application to medicine. Discusses interference and diffraction phenomena using sound wave scanning techniques. Compares focussing by zone plate to holographic image development. (GH)

A comparison of sequential and spiral scanning techniques in brain CT.

PubMed

Pace, Ivana; Zarb, Francis

2015-01-01

To evaluate and compare image quality and radiation dose of sequential computed tomography (CT) examinations of the brain and spiral CT examinations of the brain imaged on a GE HiSpeed NX/I Dual Slice 2CT scanner. A random sample of 40 patients referred for CT examination of the brain was selected and divided into 2 groups. Half of the patients were scanned using the sequential technique; the other half were scanned using the spiral technique. Radiation dose data—both the computed tomography dose index (CTDI) and the dose length product (DLP)—were recorded on a checklist at the end of each examination. Using the European Guidelines on Quality Criteria for Computed Tomography, 4 radiologists conducted a visual grading analysis and rated the level of visibility of 6 anatomical structures considered necessary to produce images of high quality. The mean CTDI(vol) and DLP values were statistically significantly higher (P <.05) with the sequential scans (CTDI(vol): 22.06 mGy; DLP: 304.60 mGy • cm) than with the spiral scans (CTDI(vol): 14.94 mGy; DLP: 229.10 mGy • cm). The mean image quality rating scores for all criteria of the sequential scanning technique were statistically significantly higher (P <.05) in the visual grading analysis than those of the spiral scanning technique. In this local study, the sequential technique was preferred over the spiral technique for both overall image quality and differentiation between gray and white matter in brain CT scans. Other similar studies counter this finding. The radiation dose seen with the sequential CT scanning technique was significantly higher than that seen with the spiral CT scanning technique. However, image quality with the sequential technique was statistically significantly superior (P <.05).

Combined illumination cylindrical millimeter-wave imaging technique for concealed weapon detection

NASA Astrophysics Data System (ADS)

Sheen, David M.; McMakin, Douglas L.; Hall, Thomas E.

2000-07-01

A novel millimeter-wave imaging technique has been developed for personnel surveillance applications, including the detection of concealed weapons, explosives, drugs, and other contraband material. Millimeter-waves are high-frequency radio waves in the frequency band of 30 - 300 GHz, and pose no health threat to humans at moderate power levels. These waves readily penetrate common clothing materials, and are reflected by the human body and by concealed items. The combined illumination cylindrical imaging concept consists of a vertical, high-resolution, millimeter-wave array of antennas which is scanned in a cylindrical manner about the person under surveillance. Using a computer, the data from this scan is mathematically reconstructed into a series of focused 3D images of the person. After reconstruction, the images are combined into a single high-resolution 3D image of the person under surveillance. This combined image is then rendered using 3D computer graphics techniques. The combined cylindrical illumination is critical as it allows the display of information from all angles. This is necessary because millimeter-waves do not penetrate the body. Ultimately, the images displayed to the operate will be icon-based to protect the privacy of the person being screened. Novel aspects of this technique include the cylindrical scanning concept and the image reconstruction algorithm, which was developed specifically for this imaging system. An engineering prototype based on this cylindrical imaging technique has been fabricated and tested. This work has been sponsored by the Federal Aviation Administration.

Measurement of polarization dependence of two-photon absorption coefficient in InP using extended Z-scan technique for thick materials

NASA Astrophysics Data System (ADS)

Oishi, Masaki; Shinozaki, Tomohisa; Hara, Hikaru; Yamamoto, Kazunuki; Matsusue, Toshio; Bando, Hiroyuki

2018-03-01

The two-photon absorption coefficient β in InP has been measured in the wavelength range of 1640 to 1800 nm by the Z-scan technique in relatively thick materials. The values of β have been evaluated from the fit to the equation including the spatial and temporal profiles of the focused Gaussian beam. The polarization dependence of β has also been measured. The dependence has been expressed very well by the expression of β with the imaginary part of the third-order nonlinear susceptibility tensor χ(3).

Atomic force microscopy of biological samples

DOE Office of Scientific and Technical Information (OSTI.GOV)

Doktycz, Mitchel John

2010-01-01

The ability to evaluate structural-functional relationships in real time has allowed scanning probe microscopy (SPM) to assume a prominent role in post genomic biological research. In this mini-review, we highlight the development of imaging and ancillary techniques that have allowed SPM to permeate many key areas of contemporary research. We begin by examining the invention of the scanning tunneling microscope (STM) by Binnig and Rohrer in 1982 and discuss how it served to team biologists with physicists to integrate high-resolution microscopy into biological science. We point to the problems of imaging nonconductive biological samples with the STM and relate howmore » this led to the evolution of the atomic force microscope (AFM) developed by Binnig, Quate, and Gerber, in 1986. Commercialization in the late 1980s established SPM as a powerful research tool in the biological research community. Contact mode AFM imaging was soon complemented by the development of non-contact imaging modes. These non-contact modes eventually became the primary focus for further new applications including the development of fast scanning methods. The extreme sensitivity of the AFM cantilever was recognized and has been developed into applications for measuring forces required for indenting biological surfaces and breaking bonds between biomolecules. Further functional augmentation to the cantilever tip allowed development of new and emerging techniques including scanning ion-conductance microscopy (SICM), scanning electrochemical microscope (SECM), Kelvin force microscopy (KFM) and scanning near field ultrasonic holography (SNFUH).« less

Computer image processing in marine resource exploration

NASA Technical Reports Server (NTRS)

Paluzzi, P. R.; Normark, W. R.; Hess, G. R.; Hess, H. D.; Cruickshank, M. J.

1976-01-01

Pictographic data or imagery is commonly used in marine exploration. Pre-existing image processing techniques (software) similar to those used on imagery obtained from unmanned planetary exploration were used to improve marine photography and side-scan sonar imagery. Features and details not visible by conventional photo processing methods were enhanced by filtering and noise removal on selected deep-sea photographs. Information gained near the periphery of photographs allows improved interpretation and facilitates construction of bottom mosaics where overlapping frames are available. Similar processing techniques were applied to side-scan sonar imagery, including corrections for slant range distortion, and along-track scale changes. The use of digital data processing and storage techniques greatly extends the quantity of information that can be handled, stored, and processed.

A correlative optical microscopy and scanning electron microscopy approach to locating nanoparticles in brain tumors.

PubMed

Kempen, Paul J; Kircher, Moritz F; de la Zerda, Adam; Zavaleta, Cristina L; Jokerst, Jesse V; Mellinghoff, Ingo K; Gambhir, Sanjiv S; Sinclair, Robert

2015-01-01

The growing use of nanoparticles in biomedical applications, including cancer diagnosis and treatment, demands the capability to exactly locate them within complex biological systems. In this work a correlative optical and scanning electron microscopy technique was developed to locate and observe multi-modal gold core nanoparticle accumulation in brain tumor models. Entire brain sections from mice containing orthotopic brain tumors injected intravenously with nanoparticles were imaged using both optical microscopy to identify the brain tumor, and scanning electron microscopy to identify the individual nanoparticles. Gold-based nanoparticles were readily identified in the scanning electron microscope using backscattered electron imaging as bright spots against a darker background. This information was then correlated to determine the exact location of the nanoparticles within the brain tissue. The nanoparticles were located only in areas that contained tumor cells, and not in the surrounding healthy brain tissue. This correlative technique provides a powerful method to relate the macro- and micro-scale features visible in light microscopy with the nanoscale features resolvable in scanning electron microscopy. Copyright © 2014 Elsevier Ltd. All rights reserved.

Interventional MR: vascular applications.

PubMed

Smits, H F; Bos, C; van der Weide, R; Bakker, C J

1999-01-01

Three strategies for visualisation of MR-dedicated guidewires and catheters have been proposed, namely active tracking, the technique of locally induced field inhomogeneity and passive susceptibility-based tracking. In this article the pros and cons of these techniques are discussed, including the development of MR-dedicated guidewires and catheters, scan techniques, post-processing tools, and display facilities for MR tracking. Finally, some of the results obtained with MR tracking are discussed.

Non-destructive characterization of SiC coated carbon-carbon composites by multiple techniques

NASA Astrophysics Data System (ADS)

Nixon, Thomas D.; Hemstad, Stan N.; Pfeifer, William H.

SiC coated carbon-carbon composites were evaluated using several non-destructive techniques as a means of quantifying the quality of both the coating and substrate. The techniques employed included dye penetrant infiltration, eddy current measurement, C-scan, and computed tomography (CT). The NDE results were then correlated to oxidation performance and destructive evaluations by electron and optical microscopy.

The validation of the Z-Scan technique for the determination of plasma glucose

NASA Astrophysics Data System (ADS)

Alves, Sarah I.; Silva, Elaine A. O.; Costa, Simone S.; Sonego, Denise R. N.; Hallack, Maira L.; Coppini, Ornela L.; Rowies, Fernanda; Azzalis, Ligia A.; Junqueira, Virginia B. C.; Pereira, Edimar C.; Rocha, Katya C.; Fonseca, Fernando L. A.

2013-11-01

Glucose is the main energy source for the human body. The concentration of blood glucose is regulated by several hormones including both antagonists: insulin and glucagon. The quantification of glucose in the blood is used for diagnosing metabolic disorders of carbohydrates, such as diabetes, idiopathic hypoglycemia and pancreatic diseases. Currently, the methodology used for this determination is the enzymatic colorimetric with spectrophotometric. This study aimed to validate the use of measurements of nonlinear optical properties of plasma glucose via the Z-Scan technique. For this we used samples of calibrator patterns that simulate commercial samples of patients (ELITech ©). Besides calibrators, serum glucose levels within acceptable reference values (normal control serum - Brazilian Society of Clinical Pathology and Laboratory Medicine) and also overestimated (pathological control serum - Brazilian Society of Clinical Pathology and Laboratory Medicine) were used in the methodology proposal. Calibrator dilutions were performed and determined by the Z-Scan technique for the preparation of calibration curve. In conclusion, Z-Scan method can be used to determinate glucose levels in biological samples with enzymatic colorimetric reaction and also to apply the same quality control parameters used in biochemistry clinical.

Galvanometer scanning technology for laser additive manufacturing

NASA Astrophysics Data System (ADS)

Luo, Xi; Li, Jin; Lucas, Mark

2017-02-01

A galvanometer laser beam scanning system is an essential element in many laser additive manufacturing (LAM) technologies including Stereolithography (SLA), Selective Laser Sintering (SLS) and Selective Laser Melting (SLM). Understanding the laser beam scanning techniques and recent innovations in this field will greatly benefit the 3D laser printing system integration and technology advance. One of the challenges to achieve high quality 3D printed parts is due to the non-uniform laser power density delivered on the materials caused by the acceleration and deceleration movements of the galvanometer at ends of the hatching and outlining patterns. One way to solve this problem is to modulate the laser power as the function of the scanning speed during the acceleration or deceleration periods. Another strategy is to maintain the constant scanning speed while accurately coordinating the laser on and off operation throughout the job. In this paper, we demonstrate the high speed, high accuracy and low drift digital scanning technology that incorporates both techniques to achieve uniform laser density with minimal additional process development. With the constant scanning speed method, the scanner not only delivers high quality and uniform results, but also a throughput increase of 23% on a typical LAM job, compared to that of the conventional control method that requires galvanometer acceleration and deceleration movements.

Helium ion microscopy and ultra-high-resolution scanning electron microscopy analysis of membrane-extracted cells reveals novel characteristics of the cytoskeleton of Giardia intestinalis.

PubMed

Gadelha, Ana Paula Rocha; Benchimol, Marlene; de Souza, Wanderley

2015-06-01

Giardia intestinalis presents a complex microtubular cytoskeleton formed by specialized structures, such as the adhesive disk, four pairs of flagella, the funis and the median body. The ultrastructural organization of the Giardia cytoskeleton has been analyzed using different microscopic techniques, including high-resolution scanning electron microscopy. Recent advances in scanning microscopy technology have opened a new venue for the characterization of cellular structures and include scanning probe microscopy techniques such as ultra-high-resolution scanning electron microscopy (UHRSEM) and helium ion microscopy (HIM). Here, we studied the organization of the cytoskeleton of G. intestinalis trophozoites using UHRSEM and HIM in membrane-extracted cells. The results revealed a number of new cytoskeletal elements associated with the lateral crest and the dorsal surface of the parasite. The fine structure of the banded collar was also observed. The marginal plates were seen linked to a network of filaments, which were continuous with filaments parallel to the main cell axis. Cytoplasmic filaments that supported the internal structures were seen by the first time. Using anti-actin antibody, we observed a labeling in these filamentous structures. Taken together, these data revealed new surface characteristics of the cytoskeleton of G. intestinalis and may contribute to an improved understanding of the structural organization of trophozoites. Copyright © 2015 Elsevier Inc. All rights reserved.

Qualitative and quantitative interpretation of SEM image using digital image processing.

PubMed

Saladra, Dawid; Kopernik, Magdalena

2016-10-01

The aim of the this study is improvement of qualitative and quantitative analysis of scanning electron microscope micrographs by development of computer program, which enables automatic crack analysis of scanning electron microscopy (SEM) micrographs. Micromechanical tests of pneumatic ventricular assist devices result in a large number of micrographs. Therefore, the analysis must be automatic. Tests for athrombogenic titanium nitride/gold coatings deposited on polymeric substrates (Bionate II) are performed. These tests include microshear, microtension and fatigue analysis. Anisotropic surface defects observed in the SEM micrographs require support for qualitative and quantitative interpretation. Improvement of qualitative analysis of scanning electron microscope images was achieved by a set of computational tools that includes binarization, simplified expanding, expanding, simple image statistic thresholding, the filters Laplacian 1, and Laplacian 2, Otsu and reverse binarization. Several modifications of the known image processing techniques and combinations of the selected image processing techniques were applied. The introduced quantitative analysis of digital scanning electron microscope images enables computation of stereological parameters such as area, crack angle, crack length, and total crack length per unit area. This study also compares the functionality of the developed computer program of digital image processing with existing applications. The described pre- and postprocessing may be helpful in scanning electron microscopy and transmission electron microscopy surface investigations. © 2016 The Authors Journal of Microscopy © 2016 Royal Microscopical Society.

Biochemistry and Molecular Biology Techniques for Person Characterization

ERIC Educational Resources Information Center

Herrero, Salvador; Ivorra, Jose Luis; Garcia-Sogo, Magdalena; Martinez-Cortina, Carmen

2008-01-01

Using the traditional serological tests and the most novel techniques for DNA fingerprinting, forensic scientists scan different traits that vary from person to person and use the data to include or exclude suspects based on matching with the evidence obtained in a criminal case. Although the forensic application of these methods is well known,…

Scan-Based Implementation of JPEG 2000 Extensions

NASA Technical Reports Server (NTRS)

Rountree, Janet C.; Webb, Brian N.; Flohr, Thomas J.; Marcellin, Michael W.

2001-01-01

JPEG 2000 Part 2 (Extensions) contains a number of technologies that are of potential interest in remote sensing applications. These include arbitrary wavelet transforms, techniques to limit boundary artifacts in tiles, multiple component transforms, and trellis-coded quantization (TCQ). We are investigating the addition of these features to the low-memory (scan-based) implementation of JPEG 2000 Part 1. A scan-based implementation of TCQ has been realized and tested, with a very small performance loss as compared with the full image (frame-based) version. A proposed amendment to JPEG 2000 Part 2 will effect the syntax changes required to make scan-based TCQ compatible with the standard.

Simultaneous fast scanning XRF, dark field, phase-, and absorption contrast tomography

NASA Astrophysics Data System (ADS)

Medjoubi, Kadda; Bonissent, Alain; Leclercq, Nicolas; Langlois, Florent; Mercère, Pascal; Somogyi, Andrea

2013-09-01

Scanning hard X-ray nanoprobe imaging provides a unique tool for probing specimens with high sensitivity and large penetration depth. Moreover, the combination of complementary techniques such as X-ray fluorescence, absorption, phase contrast and dark field imaging gives complete quantitative information on the sample structure, composition and chemistry. The multi-technique "FLYSCAN" data acquisition scheme developed at Synchrotron SOLEIL permits to perform fast continuous scanning imaging and as such makes scanning tomography techniques feasible in a time-frame well-adapted to typical user experiments. Here we present the recent results of simultaneous fast scanning multi-technique tomography performed at Soleil. This fast scanning scheme will be implemented at the Nanoscopium beamline for large field of view 2D and 3D multimodal imaging.

Fast fluorescence techniques for crystallography beamlines

PubMed Central

Stepanov, Sergey; Hilgart, Mark; Yoder, Derek W.; Makarov, Oleg; Becker, Michael; Sanishvili, Ruslan; Ogata, Craig M.; Venugopalan, Nagarajan; Aragão, David; Caffrey, Martin; Smith, Janet L.; Fischetti, Robert F.

2011-01-01

This paper reports on several developments of X-ray fluorescence techniques for macromolecular crystallography recently implemented at the National Institute of General Medical Sciences and National Cancer Institute beamlines at the Advanced Photon Source. These include (i) three-band on-the-fly energy scanning around absorption edges with adaptive positioning of the fine-step band calculated from a coarse pass; (ii) on-the-fly X-ray fluorescence rastering over rectangular domains for locating small and invisible crystals with a shuttle-scanning option for increased speed; (iii) fluorescence rastering over user-specified multi-segmented polygons; and (iv) automatic signal optimization for reduced radiation damage of samples. PMID:21808424

Automated Guided-Wave Scanning Developed to Characterize Materials and Detect Defects

NASA Technical Reports Server (NTRS)

Martin, Richard E.; Gyekenyeski, Andrew L.; Roth, Don J.

2004-01-01

The Nondestructive Evaluation (NDE) Group of the Optical Instrumentation Technology Branch at the NASA Glenn Research Center has developed a scanning system that uses guided waves to characterize materials and detect defects. The technique uses two ultrasonic transducers to interrogate the condition of a material. The sending transducer introduces an ultrasonic pulse at a point on the surface of the specimen, and the receiving transducer detects the signal after it has passed through the material. The aim of the method is to correlate certain parameters in both the time and frequency domains of the detected waveform to characteristics of the material between the two transducers. The scanning system is shown. The waveform parameters of interest include the attenuation due to internal damping, waveform shape parameters, and frequency shifts due to material changes. For the most part, guided waves are used to gauge the damage state and defect growth of materials subjected to various mechanical or environmental loads. The technique has been applied to polymer matrix composites, ceramic matrix composites, and metal matrix composites as well as metallic alloys. Historically, guided wave analysis has been a point-by-point, manual technique with waveforms collected at discrete locations and postprocessed. Data collection and analysis of this type limits the amount of detail that can be obtained. Also, the manual movement of the sensors is prone to user error and is time consuming. The development of an automated guided-wave scanning system has allowed the method to be applied to a wide variety of materials in a consistent, repeatable manner. Experimental studies have been conducted to determine the repeatability of the system as well as compare the results obtained using more traditional NDE methods. The following screen capture shows guided-wave scan results for a ceramic matrix composite plate, including images for each of nine calculated parameters. The system can display up to 18 different wave parameters. Multiple scans of the test specimen demonstrated excellent repeatability in the measurement of all the guided-wave parameters, far exceeding the traditional point-by-point technique. In addition, the scan was able to detect a subsurface defect that was confirmed using flash thermography This technology is being further refined to provide a more robust and efficient software environment. Future hardware upgrades will allow for multiple receiving transducers and the ability to scan more complex surfaces. This work supports composite materials development and testing under the Ultra-Efficient Engine Technology (UEET) Project, but it also will be applied to other material systems under development for a wide range of applications.

Mechanically scanned deployable antenna study

NASA Technical Reports Server (NTRS)

1983-01-01

The conceptual design of a Mechanically Scanned Deployable Antenna which is launched by the STS (Space Shuttle) to provide radiometric brightness temperature maps of the Earth and oceans at selected frequency bands in the frequency range of 1.4 GHz to 11 GHz is presented. Unlike previous scanning radiometric systems, multiple radiometers for each frequency are required in order to fill in the resolution cells across the swath created by the 15 meter diameter spin stabilized system. This multiple beam radiometric system is sometimes designated as a ""whiskbroom'' system in that it combines the techniques of the scanning and ""pushbroom'' type systems. The definition of the feed system including possible feed elements and location, determination of the fundamental reflector feed offset geometry including offset angles and f/D ratio, preliminary estimates of the beam efficiency of the feed reflector system, a summary of reflector mesh losses at the proposed radiometric frequency bands, an overall conceptual configuration design and preliminary structural and thermal analyses are included.

Laser scanning confocal microscopy: history, applications, and related optical sectioning techniques.

PubMed

Paddock, Stephen W; Eliceiri, Kevin W

2014-01-01

Confocal microscopy is an established light microscopical technique for imaging fluorescently labeled specimens with significant three-dimensional structure. Applications of confocal microscopy in the biomedical sciences include the imaging of the spatial distribution of macromolecules in either fixed or living cells, the automated collection of 3D data, the imaging of multiple labeled specimens and the measurement of physiological events in living cells. The laser scanning confocal microscope continues to be chosen for most routine work although a number of instruments have been developed for more specific applications. Significant improvements have been made to all areas of the confocal approach, not only to the instruments themselves, but also to the protocols of specimen preparation, to the analysis, the display, the reproduction, sharing and management of confocal images using bioinformatics techniques.

Investigation on experimental techniques to detect, locate and quantify gear noise in helicopter transmissions

NASA Technical Reports Server (NTRS)

Flanagan, P. M.; Atherton, W. J.

1985-01-01

A robotic system to automate the detection, location, and quantification of gear noise using acoustic intensity measurement techniques has been successfully developed. Major system components fabricated under this grant include an instrumentation robot arm, a robot digital control unit and system software. A commercial, desktop computer, spectrum analyzer and two microphone probe complete the equipment required for the Robotic Acoustic Intensity Measurement System (RAIMS). Large-scale acoustic studies of gear noise in helicopter transmissions cannot be performed accurately and reliably using presently available instrumentation and techniques. Operator safety is a major concern in certain gear noise studies due to the operating environment. The man-hours needed to document a noise field in situ is another shortcoming of present techniques. RAIMS was designed to reduce the labor and hazard in collecting data and to improve the accuracy and repeatability of characterizing the acoustic field by automating the measurement process. Using RAIMS a system operator can remotely control the instrumentation robot to scan surface areas and volumes generating acoustic intensity information using the two microphone technique. Acoustic intensity studies requiring hours of scan time can be performed automatically without operator assistance. During a scan sequence, the acoustic intensity probe is positioned by the robot and acoustic intensity data is collected, processed, and stored.

The Along Track Scanning Radiometer (ATSR) for ERS1

NASA Astrophysics Data System (ADS)

Delderfield, J.; Llewellyn-Jones, D. T.; Bernard, R.; de Javel, Y.; Williamson, E. J.

1986-01-01

The ATSR is an infrared imaging radiometer which has been selected to fly aboard the ESA Remote Sensing Satellite No. 1 (ERS1) with the specific objective of accurately determining global Sea Surface Temperature (SST). Novel features, including the technique of 'along track' scanning, a closed Stirling cycle cooler, and the precision on-board blackbodies are described. Instrument subsystems are identified and their design trade-offs discussed.

Preliminary design study. Shuttle modular scanning spectroradiometer

NASA Technical Reports Server (NTRS)

1975-01-01

Fundamental concepts on which to base a detailed design for a Shuttle Modular Scanning Spectroradiometer were developed, and a preliminary design is presented. The recommended design features modularity and flexibility. It includes a 75-cm f/1.7-telescope assembly in an all-reflective Schmidt configuration, a solid state scan system (pushbroom) with high resolution over a 15 deg field of view, and ten detector channels covering the spectral range from 0.45 to 12.5 micrometers. It uses charge transfer device techniques to accommodate a large number of detector elements for earth observation measurements. Methods for in-flight radiometric calibration, for image motion compensation, and for data processing are described. Recommendations for ground support equipment are included, and interfaces with the shuttle orbiter vehicle are illustrated.

New Diagnostic Aides for Melanoma

PubMed Central

Ferris, Laura K.; Harris, Ryan J.

2012-01-01

Synopsis Detection of melanoma at an early stage is crucial to improving survival rates in melanoma. Accurate diagnosis by current techniques including dermatoscopy remains difficult, and new tools are needed to improve our diagnostic abilities. This article discusses recent advances in diagnostic techniques including confocal scanning laser microscopy, MelaFind, Siascopy, noninvasive genomic detection, as well as other future possibilities to aid in diagnosing melanoma. Advantages and barriers to implementation of the various technologies are discussed as well. PMID:22800557

Optimizing Lidar Scanning Strategies for Wind Energy Measurements (Invited)

NASA Astrophysics Data System (ADS)

Newman, J. F.; Bonin, T. A.; Klein, P.; Wharton, S.; Chilson, P. B.

2013-12-01

Environmental concerns and rising fossil fuel prices have prompted rapid development in the renewable energy sector. Wind energy, in particular, has become increasingly popular in the United States. However, the intermittency of available wind energy makes it difficult to integrate wind energy into the power grid. Thus, the expansion and successful implementation of wind energy requires accurate wind resource assessments and wind power forecasts. The actual power produced by a turbine is affected by the wind speeds and turbulence levels experienced across the turbine rotor disk. Because of the range of measurement heights required for wind power estimation, remote sensing devices (e.g., lidar) are ideally suited for these purposes. However, the volume averaging inherent in remote sensing technology produces turbulence estimates that are different from those estimated by a sonic anemometer mounted on a standard meteorological tower. In addition, most lidars intended for wind energy purposes utilize a standard Doppler beam-swinging or Velocity-Azimuth Display technique to estimate the three-dimensional wind vector. These scanning strategies are ideal for measuring mean wind speeds but are likely inadequate for measuring turbulence. In order to examine the impact of different lidar scanning strategies on turbulence measurements, a WindCube lidar, a scanning Halo lidar, and a scanning Galion lidar were deployed at the Southern Great Plains Atmospheric Radiation Measurement (ARM) site in Summer 2013. Existing instrumentation at the ARM site, including a 60-m meteorological tower and an additional scanning Halo lidar, were used in conjunction with the deployed lidars to evaluate several user-defined scanning strategies. For part of the experiment, all three scanning lidars were pointed at approximately the same point in space and a tri-Doppler analysis was completed to calculate the three-dimensional wind vector every 1 second. In another part of the experiment, one of the scanning lidars ran a Doppler beam-swinging technique identical to that used by the WindCube lidar while another scanning lidar used a novel six-beam technique that has been presented in the literature as a better alternative for measuring turbulence. In this presentation, turbulence measurements from these techniques are compared to turbulence measured by the WindCube lidar and sonic anemometers on the 60-m meteorological tower. In addition, recommendations are made for lidar measurement campaigns for wind energy applications.

High-resolution measurements of the multilayer ultra-structure of articular cartilage and their translational potential

PubMed Central

2014-01-01

Current musculoskeletal imaging techniques usually target the macro-morphology of articular cartilage or use histological analysis. These techniques are able to reveal advanced osteoarthritic changes in articular cartilage but fail to give detailed information to distinguish early osteoarthritis from healthy cartilage, and this necessitates high-resolution imaging techniques measuring cells and the extracellular matrix within the multilayer structure of articular cartilage. This review provides a comprehensive exploration of the cellular components and extracellular matrix of articular cartilage as well as high-resolution imaging techniques, including magnetic resonance image, electron microscopy, confocal laser scanning microscopy, second harmonic generation microscopy, and laser scanning confocal arthroscopy, in the measurement of multilayer ultra-structures of articular cartilage. This review also provides an overview for micro-structural analysis of the main components of normal or osteoarthritic cartilage and discusses the potential and challenges associated with developing non-invasive high-resolution imaging techniques for both research and clinical diagnosis of early to late osteoarthritis. PMID:24946278

Concept and Design of a 3D Printed Support to Assist Hand Scanning for the Realization of Customized Orthosis.

PubMed

Baronio, Gabriele; Volonghi, Paola; Signoroni, Alberto

2017-01-01

In the rehabilitation field, the use of additive manufacturing techniques to realize customized orthoses is increasingly widespread. Obtaining a 3D model for the 3D printing phase can be done following different methodologies. We consider the creation of personalized upper limb orthoses, also including fingers, starting from the acquisition of the hand geometry through accurate 3D scanning. However, hand scanning procedure presents differences between healthy subjects and patients affected by pathologies that compromise upper limb functionality. In this work, we present the concept and design of a 3D printed support to assist hand scanning of such patients. The device, realized with FDM additive manufacturing techniques in ABS material, allows palmar acquisitions, and its design and test are motivated by the following needs: (1) immobilizing the hand of patients during the palmar scanning to reduce involuntary movements affecting the scanning quality and (2) keeping hands open and in a correct position, especially to contrast the high degree of hypertonicity of spastic subjects. The resulting device can be used indifferently for the right and the left hand; it is provided in four-dimensional sizes and may be also suitable as a palmar support for the acquisition of the dorsal side of the hand.

Concept and Design of a 3D Printed Support to Assist Hand Scanning for the Realization of Customized Orthosis

PubMed Central

Volonghi, Paola

2017-01-01

In the rehabilitation field, the use of additive manufacturing techniques to realize customized orthoses is increasingly widespread. Obtaining a 3D model for the 3D printing phase can be done following different methodologies. We consider the creation of personalized upper limb orthoses, also including fingers, starting from the acquisition of the hand geometry through accurate 3D scanning. However, hand scanning procedure presents differences between healthy subjects and patients affected by pathologies that compromise upper limb functionality. In this work, we present the concept and design of a 3D printed support to assist hand scanning of such patients. The device, realized with FDM additive manufacturing techniques in ABS material, allows palmar acquisitions, and its design and test are motivated by the following needs: (1) immobilizing the hand of patients during the palmar scanning to reduce involuntary movements affecting the scanning quality and (2) keeping hands open and in a correct position, especially to contrast the high degree of hypertonicity of spastic subjects. The resulting device can be used indifferently for the right and the left hand; it is provided in four-dimensional sizes and may be also suitable as a palmar support for the acquisition of the dorsal side of the hand. PMID:29234219

Plasmonic Imaging of Electrochemical Reactions of Single Nanoparticles.

PubMed

Fang, Yimin; Wang, Hui; Yu, Hui; Liu, Xianwei; Wang, Wei; Chen, Hong-Yuan; Tao, N J

2016-11-15

Electrochemical reactions are involved in many natural phenomena, and are responsible for various applications, including energy conversion and storage, material processing and protection, and chemical detection and analysis. An electrochemical reaction is accompanied by electron transfer between a chemical species and an electrode. For this reason, it has been studied by measuring current, charge, or related electrical quantities. This approach has led to the development of various electrochemical methods, which have played an essential role in the understanding and applications of electrochemistry. While powerful, most of the traditional methods lack spatial and temporal resolutions desired for studying heterogeneous electrochemical reactions on electrode surfaces and in nanoscale materials. To overcome the limitations, scanning probe microscopes have been invented to map local electrochemical reactions with nanometer resolution. Examples include the scanning electrochemical microscope and scanning electrochemical cell microscope, which directly image local electrochemical reaction current using a scanning electrode or pipet. The use of a scanning probe in these microscopes provides high spatial resolution, but at the expense of temporal resolution and throughput. This Account discusses an alternative approach to study electrochemical reactions. Instead of measuring electron transfer electrically, it detects the accompanying changes in the reactant and product concentrations on the electrode surface optically via surface plasmon resonance (SPR). SPR is highly surface sensitive, and it provides quantitative information on the surface concentrations of reactants and products vs time and electrode potential, from which local reaction kinetics can be analyzed and quantified. The plasmonic approach allows imaging of local electrochemical reactions with high temporal resolution and sensitivity, making it attractive for studying electrochemical reactions in biological systems and nanoscale materials with high throughput. The plasmonic approach has two imaging modes: electrochemical current imaging and interfacial impedance imaging. The former images local electrochemical current associated with electrochemical reactions (faradic current), and the latter maps local interfacial impedance, including nonfaradic contributions (e.g., double layer charging). The plasmonic imaging technique can perform voltammetry (cyclic or square wave) in an analogous manner to the traditional electrochemical methods. It can also be integrated with bright field, dark field, and fluorescence imaging capabilities in one optical setup to provide additional capabilities. To date the plasmonic imaging technique has found various applications, including mapping of heterogeneous surface reactions, analysis of trace substances, detection of catalytic reactions, and measurement of graphene quantum capacitance. The plasmonic and other emerging optical imaging techniques (e.g., dark field and fluorescence microscopy), together with the scanning probe-based electrochemical imaging and single nanoparticle analysis techniques, provide new capabilities for one to study single nanoparticle electrochemistry with unprecedented spatial and temporal resolutions. In this Account, we focus on imaging of electrochemical reactions at single nanoparticles.

Background and survey of bioreplication techniques.

PubMed

Pulsifer, Drew Patrick; Lakhtakia, Akhlesh

2011-09-01

Bioreplication is the direct reproduction of a biological structure in order to realize at least one specific functionality. Current bioreplication techniques include the sol-gel technique, atomic layer deposition, physical vapor deposition, and imprint lithography and casting. The combined use of a focused ion beam and a scanning electron microscope could develop into a bioreplication technique as well. Some of these techniques are more suitable for reproducing surface features, others for bulk three-dimensional structures. Industrial upscaling appears possible only for imprint lithography and casting (which can be replaced by stamping).

Cross-sectional structural parameters from densitometry

NASA Technical Reports Server (NTRS)

Cleek, Tammy M.; Whalen, Robert T.

2002-01-01

Bone densitometry has previously been used to obtain cross-sectional properties of bone from a single X-ray projection across the bone width. Using three unique projections, we have extended the method to obtain the principal area moments of inertia and orientations of the principal axes at each scan cross-section along the length of the scan. Various aluminum phantoms were used to examine scanner characteristics to develop the highest accuracy possible for in vitro non-invasive analysis of cross-sectional properties. Factors considered included X-ray photon energy, initial scan orientation, the angle spanned by the three scans (included angle), and I(min)/I(max) ratios. Principal moments of inertia were accurate to within +/-3.1% and principal angles were within +/-1 degrees of the expected value for phantoms scanned with included angles of 60 degrees and 90 degrees at the higher X-ray photon energy (140 kVp). Low standard deviations in the error (0.68-1.84%) also indicate high precision of calculated measurements with these included angles. Accuracy and precision decreased slightly when the included angle was reduced to 30 degrees. The method was then successfully applied to a pair of excised cadaveric tibiae. The accuracy and insensitivity of the algorithms to cross-sectional shape and changing isotropy (I(min)/I(max)) values when various included angles are used make this technique viable for future in vivo studies.

Surface registration technique for close-range mapping applications

NASA Astrophysics Data System (ADS)

Habib, Ayman F.; Cheng, Rita W. T.

2006-08-01

Close-range mapping applications such as cultural heritage restoration, virtual reality modeling for the entertainment industry, and anatomical feature recognition for medical activities require 3D data that is usually acquired by high resolution close-range laser scanners. Since these datasets are typically captured from different viewpoints and/or at different times, accurate registration is a crucial procedure for 3D modeling of mapped objects. Several registration techniques are available that work directly with the raw laser points or with extracted features from the point cloud. Some examples include the commonly known Iterative Closest Point (ICP) algorithm and a recently proposed technique based on matching spin-images. This research focuses on developing a surface matching algorithm that is based on the Modified Iterated Hough Transform (MIHT) and ICP to register 3D data. The proposed algorithm works directly with the raw 3D laser points and does not assume point-to-point correspondence between two laser scans. The algorithm can simultaneously establish correspondence between two surfaces and estimates the transformation parameters relating them. Experiment with two partially overlapping laser scans of a small object is performed with the proposed algorithm and shows successful registration. A high quality of fit between the two scans is achieved and improvement is found when compared to the results obtained using the spin-image technique. The results demonstrate the feasibility of the proposed algorithm for registering 3D laser scanning data in close-range mapping applications to help with the generation of complete 3D models.

Evaluation of thresholding techniques for segmenting scaffold images in tissue engineering

NASA Astrophysics Data System (ADS)

Rajagopalan, Srinivasan; Yaszemski, Michael J.; Robb, Richard A.

2004-05-01

Tissue engineering attempts to address the ever widening gap between the demand and supply of organ and tissue transplants using natural and biomimetic scaffolds. The regeneration of specific tissues aided by synthetic materials is dependent on the structural and morphometric properties of the scaffold. These properties can be derived non-destructively using quantitative analysis of high resolution microCT scans of scaffolds. Thresholding of the scanned images into polymeric and porous phase is central to the outcome of the subsequent structural and morphometric analysis. Visual thresholding of scaffolds produced using stochastic processes is inaccurate. Depending on the algorithmic assumptions made, automatic thresholding might also be inaccurate. Hence there is a need to analyze the performance of different techniques and propose alternate ones, if needed. This paper provides a quantitative comparison of different thresholding techniques for segmenting scaffold images. The thresholding algorithms examined include those that exploit spatial information, locally adaptive characteristics, histogram entropy information, histogram shape information, and clustering of gray-level information. The performance of different techniques was evaluated using established criteria, including misclassification error, edge mismatch, relative foreground error, and region non-uniformity. Algorithms that exploit local image characteristics seem to perform much better than those using global information.

Recent advances in 3D computed tomography techniques for simulation and navigation in hepatobiliary pancreatic surgery.

PubMed

Uchida, Masafumi

2014-04-01

A few years ago it could take several hours to complete a 3D image using a 3D workstation. Thanks to advances in computer science, obtaining results of interest now requires only a few minutes. Many recent 3D workstations or multimedia computers are equipped with onboard 3D virtual patient modeling software, which enables patient-specific preoperative assessment and virtual planning, navigation, and tool positioning. Although medical 3D imaging can now be conducted using various modalities, including computed tomography (CT), magnetic resonance imaging (MRI), positron emission tomography (PET), and ultrasonography (US) among others, the highest quality images are obtained using CT data, and CT images are now the most commonly used source of data for 3D simulation and navigation image. If the 2D source image is bad, no amount of 3D image manipulation in software will provide a quality 3D image. In this exhibition, the recent advances in CT imaging technique and 3D visualization of the hepatobiliary and pancreatic abnormalities are featured, including scan and image reconstruction technique, contrast-enhanced techniques, new application of advanced CT scan techniques, and new virtual reality simulation and navigation imaging. © 2014 Japanese Society of Hepato-Biliary-Pancreatic Surgery.

Applications of microscopy to genetic therapy of cystic fibrosis and other human diseases.

PubMed

Moninger, Thomas O; Nessler, Randy A; Moore, Kenneth C

2006-01-01

Gene therapy has become an extremely important and active field of biomedical research. Microscopy is an integral component of this effort. This chapter presents an overview of imaging techniques used in our facility in support of cystic fibrosis gene therapy research. Instrumentation used in these studies includes light and confocal microscopy, transmission electron microscopy, and scanning electron microscopy. Techniques outlined include negative staining, cryo-electron microscopy, three-dimentional reconstruction, enzyme cytochemistry, immunocytochemistry, and fluorescence imaging.

Extending radiative transfer models by use of Bayes rule. [in atmospheric science

NASA Technical Reports Server (NTRS)

Whitney, C.

1977-01-01

This paper presents a procedure that extends some existing radiative transfer modeling techniques to problems in atmospheric science where curvature and layering of the medium and dynamic range and angular resolution of the signal are important. Example problems include twilight and limb scan simulations. Techniques that are extended include successive orders of scattering, matrix operator, doubling, Gauss-Seidel iteration, discrete ordinates and spherical harmonics. The procedure for extending them is based on Bayes' rule from probability theory.

Technical errors in planar bone scanning.

PubMed

Naddaf, Sleiman Y; Collier, B David; Elgazzar, Abdelhamid H; Khalil, Magdy M

2004-09-01

Optimal technique for planar bone scanning improves image quality, which in turn improves diagnostic efficacy. Because planar bone scanning is one of the most frequently performed nuclear medicine examinations, maintaining high standards for this examination is a daily concern for most nuclear medicine departments. Although some problems such as patient motion are frequently encountered, the degraded images produced by many other deviations from optimal technique are rarely seen in clinical practice and therefore may be difficult to recognize. The objectives of this article are to list optimal techniques for 3-phase and whole-body bone scanning, to describe and illustrate a selection of deviations from these optimal techniques for planar bone scanning, and to explain how to minimize or avoid such technical errors.

Skeletal Scintigraphy (Bone Scan)

MedlinePlus

... The special camera and imaging techniques used in nuclear medicine include the gamma camera and single-photon emission-computed tomography (SPECT). The gamma camera, also called a scintillation camera, detects radioactive energy that is emitted from the patient's body and ...

Automatic contour propagation using deformable image registration to determine delivered dose to spinal cord in head-and-neck cancer radiotherapy.

PubMed

Yeap, P L; Noble, D J; Harrison, K; Bates, A M; Burnet, N G; Jena, R; Romanchikova, M; Sutcliffe, M P F; Thomas, S J; Barnett, G C; Benson, R J; Jefferies, S J; Parker, M A

2017-07-12

To determine delivered dose to the spinal cord, a technique has been developed to propagate manual contours from kilovoltage computed-tomography (kVCT) scans for treatment planning to megavoltage computed-tomography (MVCT) guidance scans. The technique uses the Elastix software to perform intensity-based deformable image registration of each kVCT scan to the associated MVCT scans. The registration transform is then applied to contours of the spinal cord drawn manually on the kVCT scan, to obtain contour positions on the MVCT scans. Different registration strategies have been investigated, with performance evaluated by comparing the resulting auto-contours with manual contours, drawn by oncologists. The comparison metrics include the conformity index (CI), and the distance between centres (DBC). With optimised registration, auto-contours generally agree well with manual contours. Considering all 30 MVCT scans for each of three patients, the median CI is [Formula: see text], and the median DBC is ([Formula: see text]) mm. An intra-observer comparison for the same scans gives a median CI of [Formula: see text] and a DBC of ([Formula: see text]) mm. Good levels of conformity are also obtained when auto-contours are compared with manual contours from one observer for a single MVCT scan for each of 30 patients, and when they are compared with manual contours from six observers for two MVCT scans for each of three patients. Using the auto-contours to estimate organ position at treatment time, a preliminary study of 33 patients who underwent radiotherapy for head-and-neck cancers indicates good agreement between planned and delivered dose to the spinal cord.

Automatic contour propagation using deformable image registration to determine delivered dose to spinal cord in head-and-neck cancer radiotherapy

NASA Astrophysics Data System (ADS)

Yeap, P. L.; Noble, D. J.; Harrison, K.; Bates, A. M.; Burnet, N. G.; Jena, R.; Romanchikova, M.; Sutcliffe, M. P. F.; Thomas, S. J.; Barnett, G. C.; Benson, R. J.; Jefferies, S. J.; Parker, M. A.

2017-08-01

To determine delivered dose to the spinal cord, a technique has been developed to propagate manual contours from kilovoltage computed-tomography (kVCT) scans for treatment planning to megavoltage computed-tomography (MVCT) guidance scans. The technique uses the Elastix software to perform intensity-based deformable image registration of each kVCT scan to the associated MVCT scans. The registration transform is then applied to contours of the spinal cord drawn manually on the kVCT scan, to obtain contour positions on the MVCT scans. Different registration strategies have been investigated, with performance evaluated by comparing the resulting auto-contours with manual contours, drawn by oncologists. The comparison metrics include the conformity index (CI), and the distance between centres (DBC). With optimised registration, auto-contours generally agree well with manual contours. Considering all 30 MVCT scans for each of three patients, the median CI is 0.759 +/- 0.003 , and the median DBC is (0.87 +/- 0.01 ) mm. An intra-observer comparison for the same scans gives a median CI of 0.820 +/- 0.002 and a DBC of (0.64 +/- 0.01 ) mm. Good levels of conformity are also obtained when auto-contours are compared with manual contours from one observer for a single MVCT scan for each of 30 patients, and when they are compared with manual contours from six observers for two MVCT scans for each of three patients. Using the auto-contours to estimate organ position at treatment time, a preliminary study of 33 patients who underwent radiotherapy for head-and-neck cancers indicates good agreement between planned and delivered dose to the spinal cord.

Integration of Medical Imaging Including Ultrasound into a New Clinical Anatomy Curriculum

ERIC Educational Resources Information Center

Moscova, Michelle; Bryce, Deborah A.; Sindhusake, Doungkamol; Young, Noel

2015-01-01

In 2008 a new clinical anatomy curriculum with integrated medical imaging component was introduced into the University of Sydney Medical Program. Medical imaging used for teaching the new curriculum included normal radiography, MRI, CT scans, and ultrasound imaging. These techniques were incorporated into teaching over the first two years of the…

Near-field transport imaging applied to photovoltaic materials

DOE PAGES

Xiao, Chuanxiao; Jiang, Chun -Sheng; Moseley, John; ...

2017-05-26

We developed and applied a new analytical technique - near-field transport imaging (NF-TI or simply TI) - to photovoltaic materials. Charge-carrier transport is an important factor in solar cell performance, and TI is an innovative approach that integrates a scanning electron microscope with a near-field scanning optical microscope, providing the possibility to study luminescence associated with recombination and transport with high spatial resolution. In this paper, we describe in detail the technical barriers we had to overcome to develop the technique for routine application and the data-fitting procedure used to calculate minority-carrier diffusion length values. The diffusion length measured bymore » TI agrees well with the results calculated by time-resolved photoluminescence on well-controlled gallium arsenide (GaAs) thin-film samples. We report for the first time on measurements on thin-film cadmium telluride using this technique, including the determination of effective carrier diffusion length, as well as the first near-field imaging of the effect of a single localized defect on carrier transport and recombination in a GaAs heterostructure. Furthermore, by changing the scanning setup, we were able to demonstrate near-field cathodoluminescence (CL), and correlated the results with standard CL measurements. In conclusion, the TI technique shows great potential for mapping transport properties in solar cell materials with high spatial resolution.« less

Computed tomography for non-destructive evaluation of composites: Applications and correlations

NASA Technical Reports Server (NTRS)

Goldberg, B.; Hediger, L.; Noel, E.

1985-01-01

The state-of-the-art fabrication techniques for composite materials are such that stringent species-specific acceptance criteria must be generated to insure product reliability. Non-destructive evaluation techniques including computed tomography (CT), X-ray radiography (RT), and ultrasonic scanning (UT) are investigated and compared to determine their applicability and limitations to graphite epoxy, carbon-carbon, and carbon-phenolic materials. While the techniques appear complementary, CT is shown to provide significant, heretofore unattainable data. Finally, a correlation of NDE techniques to destructive analysis is presented.

Developing Dual Polarization Applications For 45th Weather Squadron's (45 WS) New Weather Radar: A Cooperative Project With The National Space Science and Technology Center (NSSTC)

NASA Technical Reports Server (NTRS)

Roeder, W.P.; Peterson, W.A.; Carey, L.D.; Deierling, W.; McNamara, T.M.

2009-01-01

A new weather radar is being acquired for use in support of America s space program at Cape Canaveral Air Force Station, NASA Kennedy Space Center, and Patrick AFB on the east coast of central Florida. This new radar includes dual polarization capability, which has not been available to 45 WS previously. The 45 WS has teamed with NSSTC with funding from NASA Marshall Spaceflight Flight Center to improve their use of this new dual polarization capability when it is implemented operationally. The project goals include developing a temperature profile adaptive scan strategy, developing training materials, and developing forecast techniques and tools using dual polarization products. The temperature profile adaptive scan strategy will provide the scan angles that provide the optimal compromise between volume scan rate, vertical resolution, phenomena detection, data quality, and reduced cone-of-silence for the 45 WS mission. The mission requirements include outstanding detection of low level boundaries for thunderstorm prediction, excellent vertical resolution in the atmosphere electrification layer between 0 C and -20 C for lightning forecasting and Lightning Launch Commit Criteria evaluation, good detection of anvil clouds for Lightning Launch Commit Criteria evaluation, reduced cone-of-silence, fast volume scans, and many samples per pulse for good data quality. The training materials will emphasize the appropriate applications most important to the 45 WS mission. These include forecasting the onset and cessation of lightning, forecasting convective winds, and hopefully the inference of electrical fields in clouds. The training materials will focus on annotated radar imagery based on products available to the 45 WS. Other examples will include time sequenced radar products without annotation to simulate radar operations. This will reinforce the forecast concepts and also allow testing of the forecasters. The new dual polarization techniques and tools will focus on the appropriate applications for the 45 WS mission. These include forecasting the onset of lightning, the cessation of lightning, convective winds, and hopefully the inference of electrical fields in clouds. This presentation will report on the results achieved so far in the project.

Imaging of endodontic biofilms by combined microscopy (FISH/cLSM - SEM).

PubMed

Schaudinn, C; Carr, G; Gorur, A; Jaramillo, D; Costerton, J W; Webster, P

2009-08-01

Scanning electron microscopy is a useful imaging approach for the visualization of bacterial biofilms in their natural environments including their medical and dental habitats, because it allows for the exploration of large surfaces with excellent resolution of topographic features. Most biofilms in nature, however, are embedded in a thick layer of extracellular matrix that prevents a clear identification of individual bacteria by scanning electron microscopy. The use of confocal laser scanning microscopy on the other hand in combination with fluorescence in situ hybridization enables the visualization of matrix embedded bacteria in multi-layered biofilms. In our study, fluorescence in situ hybridization/confocal laser scanning microscopy and scanning electron microscopy were applied to visualize bacterial biofilm in endodontic root canals. The resulting fluorescence in situ hybridization /confocal laser scanning microscopy and scanning electron microscopy and pictures were subsequently combined into one single image to provide high-resolution information on the location of hidden bacteria. The combined use of scanning electron microscopy and fluorescence in situ hybridization / confocal laser scanning microscopy has the potential to overcome the limits of each single technique.

Virtual Ultrasound Guidance for Inexperienced Operators

NASA Technical Reports Server (NTRS)

Caine, Timothy; Martin, David

2012-01-01

Medical ultrasound or echocardiographic studies are highly operator-dependent and generally require lengthy training and internship to perfect. To obtain quality echocardiographic images in remote environments, such as on-orbit, remote guidance of studies has been employed. This technique involves minimal training for the user, coupled with remote guidance from an expert. When real-time communication or expert guidance is not available, a more autonomous system of guiding an inexperienced operator through an ultrasound study is needed. One example would be missions beyond low Earth orbit in which the time delay inherent with communication will make remote guidance impractical. The Virtual Ultrasound Guidance system is a combination of hardware and software. The hardware portion includes, but is not limited to, video glasses that allow hands-free, full-screen viewing. The glasses also allow the operator a substantial field of view below the glasses to view and operate the ultrasound system. The software is a comprehensive video program designed to guide an inexperienced operator through a detailed ultrasound or echocardiographic study without extensive training or guidance from the ground. The program contains a detailed description using video and audio to demonstrate equipment controls, ergonomics of scanning, study protocol, and scanning guidance, including recovery from sub-optimal images. The components used in the initial validation of the system include an Apple iPod Classic third-generation as the video source, and Myvue video glasses. Initially, the program prompts the operator to power-up the ultrasound and position the patient. The operator would put on the video glasses and attach them to the video source. After turning on both devices and the ultrasound system, the audio-video guidance would then instruct on patient positioning and scanning techniques. A detailed scanning protocol follows with descriptions and reference video of each view along with advice on technique. The program also instructs the operator regarding the types of images to store and how to overcome pitfalls in scanning. Images can be forwarded to the ground or other site when convenient. Following study completion, the video glasses, video source, and ultrasound system are powered down and stored. Virtually any equipment that can play back video can be used to play back the program. This includes a DVD player, personal computer, and some MP3 players.

DISTRIBUTION SYSTEM SOLIDS - A RESEARCH APPROACH

EPA Science Inventory

The U.S. EPA's AWBERC research facility is equipped with capabilities to analyze a variety of solids in support many Laboratory-wide research studies. Techniques available on site include X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microsco...

Multispectral Analysis of NMR Imagery

NASA Technical Reports Server (NTRS)

Butterfield, R. L.; Vannier, M. W. And Associates; Jordan, D.

1985-01-01

Conference paper discusses initial efforts to adapt multispectral satellite-image analysis to nuclear magnetic resonance (NMR) scans of human body. Flexibility of these techniques makes it possible to present NMR data in variety of formats, including pseudocolor composite images of pathological internal features. Techniques do not have to be greatly modified from form in which used to produce satellite maps of such Earth features as water, rock, or foliage.

A methodological evaluation of volumetric measurement techniques including three-dimensional imaging in breast surgery.

PubMed

Hoeffelin, H; Jacquemin, D; Defaweux, V; Nizet, J L

2014-01-01

Breast surgery currently remains very subjective and each intervention depends on the ability and experience of the operator. To date, no objective measurement of this anatomical region can codify surgery. In this light, we wanted to compare and validate a new technique for 3D scanning (LifeViz 3D) and its clinical application. We tested the use of the 3D LifeViz system (Quantificare) to perform volumetric calculations in various settings (in situ in cadaveric dissection, of control prostheses, and in clinical patients) and we compared this system to other techniques (CT scanning and Archimedes' principle) under the same conditions. We were able to identify the benefits (feasibility, safety, portability, and low patient stress) and limitations (underestimation of the in situ volume, subjectivity of contouring, and patient selection) of the LifeViz 3D system, concluding that the results are comparable with other measurement techniques. The prospects of this technology seem promising in numerous applications in clinical practice to limit the subjectivity of breast surgery.

A Methodological Evaluation of Volumetric Measurement Techniques including Three-Dimensional Imaging in Breast Surgery

PubMed Central

Hoeffelin, H.; Jacquemin, D.; Defaweux, V.; Nizet, J L.

2014-01-01

Breast surgery currently remains very subjective and each intervention depends on the ability and experience of the operator. To date, no objective measurement of this anatomical region can codify surgery. In this light, we wanted to compare and validate a new technique for 3D scanning (LifeViz 3D) and its clinical application. We tested the use of the 3D LifeViz system (Quantificare) to perform volumetric calculations in various settings (in situ in cadaveric dissection, of control prostheses, and in clinical patients) and we compared this system to other techniques (CT scanning and Archimedes' principle) under the same conditions. We were able to identify the benefits (feasibility, safety, portability, and low patient stress) and limitations (underestimation of the in situ volume, subjectivity of contouring, and patient selection) of the LifeViz 3D system, concluding that the results are comparable with other measurement techniques. The prospects of this technology seem promising in numerous applications in clinical practice to limit the subjectivity of breast surgery. PMID:24511536

Rocket-borne instrumentation using the resonant absorption technique to study the geocoronal and interplanetary helium emissions.

PubMed

Crifo, J F; Fahr, H J; Seidi, P; Wulf-Mathies, C

1979-09-01

A rocket payload able to perform a thorough and independent analysis of the He I 58.43340-nm geocoronal and interplanetary emissions is presented. It includes a sun-pointed resonant absorption spectrometer and a sky-scanning resonant absorption photometer. Both incorporate a similar helium resonance cell of original design featuring a most flexible pressure scanning capability and an accurate pressure measuring device, so that scanning by wavelength bandpasses from 20 down to 1 pm can be achieved. A description of the design and calibration of the instrument is given, followed by an indication of its successful operation in flight.

Applications of lasers to production metrology, control, and machine 'Vision'

NASA Astrophysics Data System (ADS)

Pryor, T. R.; Erf, R. K.; Gara, A. D.

1982-06-01

General areas of laser application to production measurement and inspection are reviewed together with the associated laser measurement techniques. The topics discussed include dimensional gauging of part profiles using laser imaging or scanning techniques, laser triangulation for surface contour measurement, surface finish measurement and defect inspection, holography and speckle techniques, and strain measurement. The emerging field of robot guidance utilizing lasers and other sensing means is examined, and, finally, the use of laser marking and reading equipment is briefly discussed.

Raster and vector processing for scanned linework

USGS Publications Warehouse

Greenlee, David D.

1987-01-01

An investigation of raster editing techniques, including thinning, filling, and node detecting, was performed by using specialized software. The techniques were based on encoding the state of the 3-by-3 neighborhood surrounding each pixel into a single byte. A prototypical method for converting the edited raster linkwork into vectors was also developed. Once vector representations of the lines were formed, they were formatted as a Digital Line Graph, and further refined by deletion of nonessential vertices and by smoothing with a curve-fitting technique.

TU-CD-207-05: A Novel Digital Tomosynthesis System Using Orthogonal Scanning Technique: A Feasibility Study

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kim, J; Park, C; Kauweloa, K

2015-06-15

Purpose: As an alternative to full tomographic imaging technique such as cone-beam computed tomography (CBCT), there is growing interest to adopt digital tomosynthesis (DTS) for the use of diagnostic as well as therapeutic applications. The aim of this study is to propose a new DTS system using novel orthogonal scanning technique, which can provide superior image quality DTS images compared to the conventional DTS scanning system. Methods: Unlike conventional DTS scanning system, the proposed DTS is reconstructed with two sets of orthogonal patient scans. 1) X-ray projections that are acquired along transverse trajectory and 2) an additional sets of X-raymore » projections acquired along the vertical direction at the mid angle of the previous transverse scan. To reconstruct DTS, we have used modified filtered backprojection technique to account for the different scanning directions of each projection set. We have evaluated the performance of our method using numerical planning CT data of liver cancer patient and a physical pelvis phantom experiment. The results were compared with conventional DTS techniques with single transverse and vertical scanning. Results: The experiments on both numerical simulation as well as physical experiment showed that the resolution as well as contrast of anatomical structures was much clearer using our method. Specifically, the image quality comparing with transversely scanned DTS showed that the edge and contrast of anatomical structures along Left-Right (LR) directions was comparable however, considerable discrepancy and enhancement could be observed along Superior-Inferior (SI) direction using our method. The opposite was observed when vertically scanned DTS was compared. Conclusion: In this study, we propose a novel DTS system using orthogonal scanning technique. The results indicated that the image quality of our novel DTS system was superior compared to conventional DTS system. This makes our DTS system potentially useful in various on-line clinical applications.« less

Application of scanning acoustic microscopy to advanced structural ceramics

NASA Technical Reports Server (NTRS)

Vary, Alex; Klima, Stanley J.

1987-01-01

A review is presentod of research investigations of several acoustic microscopy techniques for application to structural ceramics for advanced heat engines. Results obtained with scanning acoustic microscopy (SAM), scanning laser acoustic microscopy (SLAM), scanning electron acoustic microscopy (SEAM), and photoacoustic microscopy (PAM) are compared. The techniques were evaluated on research samples of green and sintered monolithic silicon nitrides and silicon carbides in the form of modulus-of-rupture bars containing deliberately introduced flaws. Strengths and limitations of the techniques are described with emphasis on statistics of detectability of flaws that constitute potential fracture origins.

Three-Dimensional Optical Coherence Tomography

NASA Technical Reports Server (NTRS)

Gutin, Mikhail; Wang, Xu-Ming; Gutin, Olga

2009-01-01

Three-dimensional (3D) optical coherence tomography (OCT) is an advanced method of noninvasive infrared imaging of tissues in depth. Heretofore, commercial OCT systems for 3D imaging have been designed principally for external ophthalmological examination. As explained below, such systems have been based on a one-dimensional OCT principle, and in the operation of such a system, 3D imaging is accomplished partly by means of a combination of electronic scanning along the optical (Z) axis and mechanical scanning along the two axes (X and Y) orthogonal to the optical axis. In 3D OCT, 3D imaging involves a form of electronic scanning (without mechanical scanning) along all three axes. Consequently, the need for mechanical adjustment is minimal and the mechanism used to position the OCT probe can be correspondingly more compact. A 3D OCT system also includes a probe of improved design and utilizes advanced signal- processing techniques. Improvements in performance over prior OCT systems include finer resolution, greater speed, and greater depth of field.

Novel grid-based optical Braille conversion: from scanning to wording

NASA Astrophysics Data System (ADS)

Yoosefi Babadi, Majid; Jafari, Shahram

2011-12-01

Grid-based optical Braille conversion (GOBCO) is explained in this article. The grid-fitting technique involves processing scanned images taken from old hard-copy Braille manuscripts, recognising and converting them into English ASCII text documents inside a computer. The resulted words are verified using the relevant dictionary to provide the final output. The algorithms employed in this article can be easily modified to be implemented on other visual pattern recognition systems and text extraction applications. This technique has several advantages including: simplicity of the algorithm, high speed of execution, ability to help visually impaired persons and blind people to work with fax machines and the like, and the ability to help sighted people with no prior knowledge of Braille to understand hard-copy Braille manuscripts.

Imaging interactions of metal oxide nanoparticles with macrophage cells by ultra-high resolution scanning electron microscopy techniques.

PubMed

Plascencia-Villa, Germán; Starr, Clarise R; Armstrong, Linda S; Ponce, Arturo; José-Yacamán, Miguel

2012-11-01

Use of engineered metal oxide nanoparticles in a plethora of biological applications and custom products has warned about some possible dose-dependent cytotoxic effects. Macrophages are key components of the innate immune system used to study possible toxic effects and internalization of different nanoparticulate materials. In this work, ultra-high resolution field emission scanning electron microscopy (FE-SEM) was used to offer new insights into the dynamical processes of interaction of nanomaterials with macrophage cells dosed with different concentrations of metal oxide nanoparticles (CeO(2), TiO(2) and ZnO). The versatility of FE-SEM has allowed obtaining a detailed characterization of processes of adsorption and endocytosis of nanoparticles, by using advanced analytical and imaging techniques on complete unstained uncoated cells, including secondary electron imaging, high-sensitive backscattered electron imaging, X-ray microanalysis and stereoimaging. Low voltage BF/DF-STEM confirmed nanoparticle adsorption and internalization into endosomes of CeO(2) and TiO(2), whereas ZnO develop apoptosis after 24 h of interaction caused by dissolution and invasion of cell nucleus. Ultra-high resolution scanning electron microscopy techniques provided new insights into interactions of inorganic nanoparticles with macrophage cells with high spatial resolution.

Knowledge-based automated technique for measuring total lung volume from CT

NASA Astrophysics Data System (ADS)

Brown, Matthew S.; McNitt-Gray, Michael F.; Mankovich, Nicholas J.; Goldin, Jonathan G.; Aberle, Denise R.

1996-04-01

A robust, automated technique has been developed for estimating total lung volumes from chest computed tomography (CT) images. The technique includes a method for segmenting major chest anatomy. A knowledge-based approach automates the calculation of separate volumes of the whole thorax, lungs, and central tracheo-bronchial tree from volumetric CT data sets. A simple, explicit 3D model describes properties such as shape, topology and X-ray attenuation, of the relevant anatomy, which constrain the segmentation of these anatomic structures. Total lung volume is estimated as the sum of the right and left lungs and excludes the central airways. The method requires no operator intervention. In preliminary testing, the system was applied to image data from two healthy subjects and four patients with emphysema who underwent both helical CT and pulmonary function tests. To obtain single breath-hold scans, the healthy subjects were scanned with a collimation of 5 mm and a pitch of 1.5, while the emphysema patients were scanned with collimation of 10 mm at a pitch of 2.0. CT data were reconstructed as contiguous image sets. Automatically calculated volumes were consistent with body plethysmography results (< 10% difference).

Impulse excitation scanning acoustic microscopy for local quantification of Rayleigh surface wave velocity using B-scan analysis

NASA Astrophysics Data System (ADS)

Cherry, M.; Dierken, J.; Boehnlein, T.; Pilchak, A.; Sathish, S.; Grandhi, R.

2018-01-01

A new technique for performing quantitative scanning acoustic microscopy imaging of Rayleigh surface wave (RSW) velocity was developed based on b-scan processing. In this technique, the focused acoustic beam is moved through many defocus distances over the sample and excited with an impulse excitation, and advanced algorithms based on frequency filtering and the Hilbert transform are used to post-process the b-scans to estimate the Rayleigh surface wave velocity. The new method was used to estimate the RSW velocity on an optically flat E6 glass sample, and the velocity was measured at ±2 m/s and the scanning time per point was on the order of 1.0 s, which are both improvement from the previous two-point defocus method. The new method was also applied to the analysis of two titanium samples, and the velocity was estimated with very low standard deviation in certain large grains on the sample. A new behavior was observed with the b-scan analysis technique where the amplitude of the surface wave decayed dramatically on certain crystallographic orientations. The new technique was also compared with previous results, and the new technique has been found to be much more reliable and to have higher contrast than previously possible with impulse excitation.

Laser Scanning In Inspection

NASA Astrophysics Data System (ADS)

West, Patricia; Baker, Lionel R.

1989-03-01

This paper is a review of the applications of laser scanning in inspection. The reasons for the choice of a laser in flying spot scanning and the optical properties of a laser beam which are of value in a scanning instrument will be given. The many methods of scanning laser beams in both one and two dimensions will be described. The use of one dimensional laser scanners for automatic surface inspection for transmitting and reflective products will be covered in detail, with particular emphasis on light collection techniques. On-line inspection applications which will be mentioned include: photographic film web, metal strip products, paper web, glass sheet, car body paint surfaces and internal cylinder bores. Two dimensional laser scanning is employed in applications where increased resolution, increased depth of focus, and better contrast are required compared with conventional vidicon TV or solid state array cameras. Such examples as special microscope laser scanning systems and a TV compatible system for use in restricted areas of a nuclear reactor will be described. The technical and economic benefits and limitations of laser scanning video systems will be compared with conventional TV and CCD array devices.

Landsat real-time processing

DOE Office of Scientific and Technical Information (OSTI.GOV)

Davis, E.L.

A novel method for performing real-time acquisition and processing Landsat/EROS data covers all aspects including radiometric and geometric corrections of multispectral scanner or return-beam vidicon inputs, image enhancement, statistical analysis, feature extraction, and classification. Radiometric transformations include bias/gain adjustment, noise suppression, calibration, scan angle compensation, and illumination compensation, including topography and atmospheric effects. Correction or compensation for geometric distortion includes sensor-related distortions, such as centering, skew, size, scan nonlinearity, radial symmetry, and tangential symmetry. Also included are object image-related distortions such as aspect angle (altitude), scale distortion (altitude), terrain relief, and earth curvature. Ephemeral corrections are also applied to compensatemore » for satellite forward movement, earth rotation, altitude variations, satellite vibration, and mirror scan velocity. Image enhancement includes high-pass, low-pass, and Laplacian mask filtering and data restoration for intermittent losses. Resource classification is provided by statistical analysis including histograms, correlational analysis, matrix manipulations, and determination of spectral responses. Feature extraction includes spatial frequency analysis, which is used in parallel discriminant functions in each array processor for rapid determination. The technique uses integrated parallel array processors that decimate the tasks concurrently under supervision of a control processor. The operator-machine interface is optimized for programming ease and graphics image windowing.« less

Dental Students' Perceptions of Digital and Conventional Impression Techniques: A Randomized Controlled Trial.

PubMed

Zitzmann, Nicola U; Kovaltschuk, Irina; Lenherr, Patrik; Dedem, Philipp; Joda, Tim

2017-10-01

The aim of this randomized controlled trial was to analyze inexperienced dental students' perceptions of the difficulty and applicability of digital and conventional implant impressions and their preferences including performance. Fifty undergraduate dental students at a dental school in Switzerland were randomly divided into two groups (2×25). Group A first took digital impressions in a standardized phantom model and then conventional impressions, while the procedures were reversed for Group B. Participants were asked to complete a VAS questionnaire (0-100) on the level of difficulty and applicability (user/patient-friendliness) of both techniques. They were asked which technique they preferred and perceived to be more efficient. A quotient of "effective scan time per software-recorded time" (TRIOS) was calculated as an objective quality indicator for intraoral optical scanning (IOS). The majority of students perceived IOS as easier than the conventional technique. Most (72%) preferred the digital approach using IOS to take the implant impression to the conventional method (12%) or had no preference (12%). Although total work was similar for males and females, the TRIOS quotient indicated that male students tended to use their time more efficiently. In this study, dental students with no clinical experience were very capable of acquiring digital tools, indicating that digital impression techniques can be included early in the dental curriculum to help them catch up with ongoing development in computer-assisted technologies used in oral rehabilitation.

Smart align -- A new tool for robust non-rigid registration of scanning microscope data

DOE PAGES

Jones, Lewys; Yang, Hao; Pennycook, Timothy J.; ...

2015-07-10

Many microscopic investigations of materials may benefit from the recording of multiple successive images. This can include techniques common to several types of microscopy such as frame averaging to improve signal-to-noise ratios (SNR) or time series to study dynamic processes or more specific applications. In the scanning transmission electron microscope, this might include focal series for optical sectioning or aberration measurement, beam damage studies or camera-length series to study the effects of strain; whilst in the scanning tunnelling microscope, this might include bias voltage series to probe local electronic structure. Whatever the application, such investigations must begin with the carefulmore » alignment of these data stacks, an operation that is not always trivial. In addition, the presence of low-frequency scanning distortions can introduce intra-image shifts to the data. Here, we describe an improved automated method of performing non-rigid registration customised for the challenges unique to scanned microscope data specifically addressing the issues of low-SNR data, images containing a large proportion of crystalline material and/or local features of interest such as dislocations or edges. Careful attention has been paid to artefact testing of the non-rigid registration method used, and the importance of this registration for the quantitative interpretation of feature intensities and positions is evaluated.« less

Smart align -- A new tool for robust non-rigid registration of scanning microscope data

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jones, Lewys; Yang, Hao; Pennycook, Timothy J.

Many microscopic investigations of materials may benefit from the recording of multiple successive images. This can include techniques common to several types of microscopy such as frame averaging to improve signal-to-noise ratios (SNR) or time series to study dynamic processes or more specific applications. In the scanning transmission electron microscope, this might include focal series for optical sectioning or aberration measurement, beam damage studies or camera-length series to study the effects of strain; whilst in the scanning tunnelling microscope, this might include bias voltage series to probe local electronic structure. Whatever the application, such investigations must begin with the carefulmore » alignment of these data stacks, an operation that is not always trivial. In addition, the presence of low-frequency scanning distortions can introduce intra-image shifts to the data. Here, we describe an improved automated method of performing non-rigid registration customised for the challenges unique to scanned microscope data specifically addressing the issues of low-SNR data, images containing a large proportion of crystalline material and/or local features of interest such as dislocations or edges. Careful attention has been paid to artefact testing of the non-rigid registration method used, and the importance of this registration for the quantitative interpretation of feature intensities and positions is evaluated.« less

Reconstruction of a time-averaged midposition CT scan for radiotherapy planning of lung cancer patients using deformable registration.

PubMed

Wolthaus, J W H; Sonke, J J; van Herk, M; Damen, E M F

2008-09-01

lower lobe lung tumors move with amplitudes of up to 2 cm due to respiration. To reduce respiration imaging artifacts in planning CT scans, 4D imaging techniques are used. Currently, we use a single (midventilation) frame of the 4D data set for clinical delineation of structures and radiotherapy planning. A single frame, however, often contains artifacts due to breathing irregularities, and is noisier than a conventional CT scan since the exposure per frame is lower. Moreover, the tumor may be displaced from the mean tumor position due to hysteresis. The aim of this work is to develop a framework for the acquisition of a good quality scan representing all scanned anatomy in the mean position by averaging transformed (deformed) CT frames, i.e., canceling out motion. A nonrigid registration method is necessary since motion varies over the lung. 4D and inspiration breath-hold (BH) CT scans were acquired for 13 patients. An iterative multiscale motion estimation technique was applied to the 4D CT scan, similar to optical flow but using image phase (gray-value transitions from bright to dark and vice versa) instead. From the (4D) deformation vector field (DVF) derived, the local mean position in the respiratory cycle was computed and the 4D DVF was modified to deform all structures of the original 4D CT scan to this mean position. A 3D midposition (MidP) CT scan was then obtained by (arithmetic or median) averaging of the deformed 4D CT scan. Image registration accuracy, tumor shape deviation with respect to the BH CT scan, and noise were determined to evaluate the image fidelity of the MidP CT scan and the performance of the technique. Accuracy of the used deformable image registration method was comparable to established automated locally rigid registration and to manual landmark registration (average difference to both methods < 0.5 mm for all directions) for the tumor region. From visual assessment, the registration was good for the clearly visible features (e.g., tumor and diaphragm). The shape of the tumor, with respect to that of the BH CT scan, was better represented by the MidP reconstructions than any of the 4D CT frames (including MidV; reduction of "shape differences" was 66%). The MidP scans contained about one-third the noise of individual 4D CT scan frames. We implemented an accurate method to estimate the motion of structures in a 4D CT scan. Subsequently, a novel method to create a midposition CT scan (time-weighted average of the anatomy) for treatment planning with reduced noise and artifacts was introduced. Tumor shape and position in the MidP CT scan represents that of the BH CT scan better than MidV CT scan and, therefore, was found to be appropriate for treatment planning.

Medical Imaging with Ultrasound: Some Basic Physics.

ERIC Educational Resources Information Center

Gosling, R.

1989-01-01

Discussed are medical applications of ultrasound. The physics of the wave nature of ultrasound including its propagation and production, return by the body, spatial and contrast resolution, attenuation, image formation using pulsed echo ultrasound techniques, measurement of velocity and duplex scanning are described. (YP)

Low frequency ultrasonic nondestructive inspection of aluminum/adhesive fuselage lap splices

DOE Office of Scientific and Technical Information (OSTI.GOV)

Patton, Thadd

1994-01-04

This thesis is a collection of research efforts in ultrasonics, conducted at the Center for Aviation Systems Reliability located at Iowa State University, as part of the Federal Aviation Administration`s ``Aging Aircraft Program.`` The research was directed toward the development of an ultrasonic prototype to inspect the aluminum/adhesive fuselage lap splices found on 1970`s vintage Boeing passenger aircraft. The ultrasonic prototype consists of a normal incidence, low frequency inspection technique, and a scanning adapter that allows focused immersion transducers to be operated in a direct contact manner in any inspection orientation, including upside-down. The inspection technique uses a computer-controlled datamore » acquisition system to produce a C-scan image of a radio frequency (RF) waveform created by a low frequency, broadband, focused beam transducer, driven with a spike voltage pulser. C-scans produced by this technique are color representations of the received signal`s peak-to-peak amplitude (voltage) taken over an (x, y) grid. Low frequency, in this context, refers to a wavelength that is greater than the lap splice`s layer thicknesses. With the low frequency technique, interface echoes of the lap splice are not resolved and gating of the signal is unnecessary; this in itself makes the technique simple to implement and saves considerable time in data acquisition. Along with the advantages in data acquisition, the low frequency technique is relatively insensitive to minor surface curvature and to ultrasonic interference effects caused by adhesive bondline thickness variations in the lap splice.« less

MMX-I: data-processing software for multimodal X-ray imaging and tomography.

PubMed

Bergamaschi, Antoine; Medjoubi, Kadda; Messaoudi, Cédric; Marco, Sergio; Somogyi, Andrea

2016-05-01

A new multi-platform freeware has been developed for the processing and reconstruction of scanning multi-technique X-ray imaging and tomography datasets. The software platform aims to treat different scanning imaging techniques: X-ray fluorescence, phase, absorption and dark field and any of their combinations, thus providing an easy-to-use data processing tool for the X-ray imaging user community. A dedicated data input stream copes with the input and management of large datasets (several hundred GB) collected during a typical multi-technique fast scan at the Nanoscopium beamline and even on a standard PC. To the authors' knowledge, this is the first software tool that aims at treating all of the modalities of scanning multi-technique imaging and tomography experiments.

3D light scanning macrography.

PubMed

Huber, D; Keller, M; Robert, D

2001-08-01

The technique of 3D light scanning macrography permits the non-invasive surface scanning of small specimens at magnifications up to 200x. Obviating both the problem of limited depth of field inherent to conventional close-up macrophotography and the metallic coating required by scanning electron microscopy, 3D light scanning macrography provides three-dimensional digital images of intact specimens without the loss of colour, texture and transparency information. This newly developed technique offers a versatile, portable and cost-efficient method for the non-invasive digital and photographic documentation of small objects. Computer controlled device operation and digital image acquisition facilitate fast and accurate quantitative morphometric investigations, and the technique offers a broad field of research and educational applications in biological, medical and materials sciences.

Atomic-scale mapping of electronic structures across heterointerfaces by cross-sectional scanning tunneling microscopy

NASA Astrophysics Data System (ADS)

Chiu, Ya-Ping; Huang, Bo-Chao; Shih, Min-Chuan; Huang, Po-Cheng; Chen, Chun-Wei

2015-09-01

Interfacial science has received much attention recently based on the development of state-of-the-art analytical tools that can create and manipulate the charge, spin, orbital, and lattice degrees of freedom at interfaces. Motivated by the importance of nanoscale interfacial science that governs device operation, we present a technique to probe the electronic characteristics of heterointerfaces with atomic resolution. In this work, the interfacial characteristics of heteroepitaxial structures are investigated and the fundamental mechanisms that pertain in these systems are elucidated through cross-sectional scanning tunneling microscopy (XSTM). The XSTM technique is employed here to directly observe epitaxial interfacial structures and probe local electronic properties with atomic-level capability. Scanning tunneling microscopy and spectroscopy experiments with atomic precision provide insight into the origin and spatial distribution of electronic properties across heterointerfaces. The first part of this report provides a brief description of the cleavage technique and spectroscopy analysis in XSTM measurements. The second part addresses interfacial electronic structures of several model heterostructures in current condensed matter research using XSTM. Topics to be discussed include high-κ‘s/III-V’s semiconductors, polymer heterojunctions, and complex oxide heterostructures, which are all material systems whose investigation using this technique is expected to benefit the research community. Finally, practical aspects and perspectives of using XSTM in interface science are presented.

Scanning probe microscopy of biomedical interfaces

NASA Astrophysics Data System (ADS)

Vansteenkiste, S. O.; Davies, M. C.; Roberts, C. J.; Tendler, S. J. B.; Williams, P. M.

1998-02-01

The development of the scanning probe microscopes over the past decade has provided a number of exciting new surface analytical techniques making a significant progress in the characterisation of biomedical interfaces. In this review, several examples are presented to illustrate that SPM is a powerful and promising tool for surface investigations including biomolecules, cell membranes, polymers and even living cells. The ability of the SPM instrument to monitor adhesion phenomena and provide quantitative information about intermolecular interactions is also described. Moreover, the huge potential of the scanning probe microscopes to study dynamic processes at interfaces under nearly physiological conditions is highlighted. Novel applications in the field of biochemistry, microbiology, biomaterial engineering, drug delivery and even medicine are discussed.

In vivo confocal microscopy, an inner vision of the cornea - a major review.

PubMed

Guthoff, Rudolf F; Zhivov, Andrey; Stachs, Oliver

2009-01-01

The demands of modern ophthalmology have evolved from descriptive findings from the slit lamp to in vivo assessment of cellular level changes. Nowadays, the latter can be provided by in vivo confocal microscopy. This article gives an overview of confocal principles using tandem scanning, scanning slit and laser scanning techniques used in ophthalmology. The main part of the paper describes the clinical applications emphasizing the anatomy of the normal and pathological cornea, and illustrates side-effects of topical medication, contact lens wear, cross-linking and refractive surgery. Finally, a summary about experimental applications, including animal studies, surface characterization and volume rendering as well as future developments, is given.

Unlocking the spatial inversion of large scanning magnetic microscopy datasets

NASA Astrophysics Data System (ADS)

Myre, J. M.; Lascu, I.; Andrade Lima, E.; Feinberg, J. M.; Saar, M. O.; Weiss, B. P.

2013-12-01

Modern scanning magnetic microscopy provides the ability to perform high-resolution, ultra-high sensitivity moment magnetometry, with spatial resolutions better than 10^-4 m and magnetic moments as weak as 10^-16 Am^2. These microscopy capabilities have enhanced numerous magnetic studies, including investigations of the paleointensity of the Earth's magnetic field, shock magnetization and demagnetization of impacts, magnetostratigraphy, the magnetic record in speleothems, and the records of ancient core dynamos of planetary bodies. A common component among many studies utilizing scanning magnetic microscopy is solving an inverse problem to determine the non-negative magnitude of the magnetic moments that produce the measured component of the magnetic field. The two most frequently used methods to solve this inverse problem are classic fast Fourier techniques in the frequency domain and non-negative least squares (NNLS) methods in the spatial domain. Although Fourier techniques are extremely fast, they typically violate non-negativity and it is difficult to implement constraints associated with the space domain. NNLS methods do not violate non-negativity, but have typically been computation time prohibitive for samples of practical size or resolution. Existing NNLS methods use multiple techniques to attain tractable computation. To reduce computation time in the past, typically sample size or scan resolution would have to be reduced. Similarly, multiple inversions of smaller sample subdivisions can be performed, although this frequently results in undesirable artifacts at subdivision boundaries. Dipole interactions can also be filtered to only compute interactions above a threshold which enables the use of sparse methods through artificial sparsity. To improve upon existing spatial domain techniques, we present the application of the TNT algorithm, named TNT as it is a "dynamite" non-negative least squares algorithm which enhances the performance and accuracy of spatial domain inversions. We show that the TNT algorithm reduces the execution time of spatial domain inversions from months to hours and that inverse solution accuracy is improved as the TNT algorithm naturally produces solutions with small norms. Using sIRM and NRM measures of multiple synthetic and natural samples we show that the capabilities of the TNT algorithm allow very large samples to be inverted without the need for alternative techniques to make the problems tractable. Ultimately, the TNT algorithm enables accurate spatial domain analysis of scanning magnetic microscopy data on an accelerated time scale that renders spatial domain analyses tractable for numerous studies, including searches for the best fit of unidirectional magnetization direction and high-resolution step-wise magnetization and demagnetization.

Different methods for anatomical targeting.

PubMed

Iacopino, D G; Conti, A; Angileri, F F; Tomasello, F

2003-03-01

Several procedures are used in the different neurosurgical centers in order to perform stereotactic surgery for movement disorders. At the moment no procedure can really be considered superior to the other. We contribute with our experience of targeting method. Ten patients were selected, in accordance to the guidelines for the treatment of Parkinson disease, and operated by several methods including pallidotomy, bilateral insertion of chronic deep brain electrodes within the internal pallidum and in the subthalamic nucleus (18 procedures). in each patient an MR scan was performed the day before surgery. Scans were performed axially parallel to the intercommissural line. The operating day a contrast CT scan was performed under stereotactic conditions. after digitalization of the MRI images, it was possible to visualize the surgical target and to relate it to parenchimal and vascular anatomic structures readable at the CT examination. The CT scan obtained was confronted with the MR previously performed, the geometrical relation between the different parenchimal and vascular structures and the selected targets were obtained. Stereotactic coordinates were obtained on the CT examination. It was possible to calculate the position of the subthalamic nucleus and of the internal pallidum on the CT scan, not only relating to the intercommissural line, but considering also the neurovascular structures displayed both on the MRI and the CT scans. The technique that our group presents consist in an integration between information derived from the CT and the MR techniques, so that we can benefit from the advantages of both methods and overcome the disadvantages.

In silico comparison of the reproducibility of full-arch implant provisional restorations to final restoration between a 3D Scan/CAD/CAM technique and the conventional method.

PubMed

Mino, Takuya; Maekawa, Kenji; Ueda, Akihiro; Higuchi, Shizuo; Sejima, Junichi; Takeuchi, Tetsuo; Hara, Emilio Satoshi; Kimura-Ono, Aya; Sonoyama, Wataru; Kuboki, Takuo

2015-04-01

The aim of this article was to investigate the accuracy in the reproducibility of full-arch implant provisional restorations to final restorations between a 3D Scan/CAD/CAM technique and the conventional method. We fabricated two final restorations for rehabilitation of maxillary and mandibular complete edentulous area and performed a computer-based comparative analysis of the accuracy in the reproducibility of the provisional restoration to final restoration between a 3D scanning and CAD/CAM (Scan/CAD/CAM) technique and the conventional silicone-mold transfer technique. Final restorations fabricated either by the conventional or Scan/CAD/CAM method were successfully installed in the patient. The total concave/convex volume discrepancy observed with the Scan/CAD/CAM technique was 503.50mm(3) and 338.15 mm(3) for maxillary and mandibular implant-supported prostheses (ISPs), respectively. On the other hand, total concave/convex volume discrepancy observed with the conventional method was markedly high (1106.84 mm(3) and 771.23 mm(3) for maxillary and mandibular ISPs, respectively). The results of the present report suggest that Scan/CAD/CAM method enables a more precise and accurate transfer of provisional restorations to final restorations compared to the conventional method. Copyright © 2014 Japan Prosthodontic Society. Published by Elsevier Ltd. All rights reserved.

Systematic Review of Synthetic Computed Tomography Generation Methodologies for Use in Magnetic Resonance Imaging-Only Radiation Therapy.

PubMed

Johnstone, Emily; Wyatt, Jonathan J; Henry, Ann M; Short, Susan C; Sebag-Montefiore, David; Murray, Louise; Kelly, Charles G; McCallum, Hazel M; Speight, Richard

2018-01-01

Magnetic resonance imaging (MRI) offers superior soft-tissue contrast as compared with computed tomography (CT), which is conventionally used for radiation therapy treatment planning (RTP) and patient positioning verification, resulting in improved target definition. The 2 modalities are co-registered for RTP; however, this introduces a systematic error. Implementing an MRI-only radiation therapy workflow would be advantageous because this error would be eliminated, the patient pathway simplified, and patient dose reduced. Unlike CT, in MRI there is no direct relationship between signal intensity and electron density; however, various methodologies for MRI-only RTP have been reported. A systematic review of these methods was undertaken. The PRISMA guidelines were followed. Embase and Medline databases were searched (1996 to March, 2017) for studies that generated synthetic CT scans (sCT)s for MRI-only radiation therapy. Sixty-one articles met the inclusion criteria. This review showed that MRI-only RTP techniques could be grouped into 3 categories: (1) bulk density override; (2) atlas-based; and (3) voxel-based techniques, which all produce an sCT scan from MR images. Bulk density override techniques either used a single homogeneous or multiple tissue override. The former produced large dosimetric errors (>2%) in some cases and the latter frequently required manual bone contouring. Atlas-based techniques used both single and multiple atlases and included methods incorporating pattern recognition techniques. Clinically acceptable sCTs were reported, but atypical anatomy led to erroneous results in some cases. Voxel-based techniques included methods using routine and specialized MRI sequences, namely ultra-short echo time imaging. High-quality sCTs were produced; however, use of multiple sequences led to long scanning times increasing the chances of patient movement. Using nonroutine sequences would currently be problematic in most radiation therapy centers. Atlas-based and voxel-based techniques were found to be the most clinically useful methods, with some studies reporting dosimetric differences of <1% between planning on the sCT and CT and <1-mm deviations when using sCTs for positional verification. Copyright © 2017 Elsevier Inc. All rights reserved.

Brain Imaging in Children with Neurodevelopmental Disorders.

ERIC Educational Resources Information Center

Mantovani, John F.

1994-01-01

This article reviews neuroimaging techniques such as cranial ultrasound, computed tomography scanning, and magnetic resonance imaging. Their roles in the care of children with neurodevelopmental disabilities include identification of high-risk infants, establishment of the diagnosis and prognosis in affected children, and enhancement of discussion…

Visualizing Practice with Children and Families.

ERIC Educational Resources Information Center

Mattaini, Mark A.

1995-01-01

Argues that graphic images and technologies can be of substantial help to social work practitioners for assessment and intervention with children and families. Suggests a range of graphic tools and techniques, including profiles, ecomaps, sequential ecomaps, contingency diagrams, concurrent graphing, and computerized Visual EcoScan. (DR)

Biochemical Imaging of Gliomas Using MR Spectroscopic Imaging for Radiotherapy Treatment Planning

NASA Astrophysics Data System (ADS)

Heikal, Amr Ahmed

This thesis discusses the main obstacles facing wide clinical implementation of magnetic resonance spectroscopic imaging (MRSI) as a tumor delineation tool for radiotherapy treatment planning, particularly for gliomas. These main obstacles are identified as 1. observer bias and poor interpretational reproducibility of the results of MRSI scans, and 2. the long scan times required to conduct MRSI scans. An examination of an existing user-independent MRSI tumor delineation technique known as the choline-to-NAA index (CNI) is conducted to assess its utility in providing a tool for reproducible interpretation of MRSI results. While working with spatial resolutions typically twice those on which the CNI model was originally designed, a region of statistical uncertainty was discovered between the tumor and normal tissue populations and as such a modification to the CNI model was introduced to clearly identify that region. To address the issue of long scan times, a series of studies were conducted to adapt a scan acceleration technique, compressed sensing (CS), to work with MRSI and to quantify the effects of such a novel technique on the modulation transfer function (MTF), an important quantitative imaging metric. The studies included the development of the first phantom based method of measuring the MTF for MRSI data, a study of the correlation between the k-space sampling patterns used for compressed sensing and the resulting MTFs, and the introduction of a technique circumventing some of side-effects of compressed sensing by exploiting the conjugate symmetry property of k-space. The work in this thesis provides two essential steps towards wide clinical implementation of MRSI-based tumor delineation. The proposed modifications to the CNI method coupled with the application of CS to MRSI address the two main obstacles outlined. However, there continues to be room for improvement and questions that need to be answered by future research.

A photogrammetric technique for generation of an accurate multispectral optical flow dataset

NASA Astrophysics Data System (ADS)

Kniaz, V. V.

2017-06-01

A presence of an accurate dataset is the key requirement for a successful development of an optical flow estimation algorithm. A large number of freely available optical flow datasets were developed in recent years and gave rise for many powerful algorithms. However most of the datasets include only images captured in the visible spectrum. This paper is focused on the creation of a multispectral optical flow dataset with an accurate ground truth. The generation of an accurate ground truth optical flow is a rather complex problem, as no device for error-free optical flow measurement was developed to date. Existing methods for ground truth optical flow estimation are based on hidden textures, 3D modelling or laser scanning. Such techniques are either work only with a synthetic optical flow or provide a sparse ground truth optical flow. In this paper a new photogrammetric method for generation of an accurate ground truth optical flow is proposed. The method combines the benefits of the accuracy and density of a synthetic optical flow datasets with the flexibility of laser scanning based techniques. A multispectral dataset including various image sequences was generated using the developed method. The dataset is freely available on the accompanying web site.

Lesion Detection in CT Images Using Deep Learning Semantic Segmentation Technique

NASA Astrophysics Data System (ADS)

Kalinovsky, A.; Liauchuk, V.; Tarasau, A.

2017-05-01

In this paper, the problem of automatic detection of tuberculosis lesion on 3D lung CT images is considered as a benchmark for testing out algorithms based on a modern concept of Deep Learning. For training and testing of the algorithms a domestic dataset of 338 3D CT scans of tuberculosis patients with manually labelled lesions was used. The algorithms which are based on using Deep Convolutional Networks were implemented and applied in three different ways including slice-wise lesion detection in 2D images using semantic segmentation, slice-wise lesion detection in 2D images using sliding window technique as well as straightforward detection of lesions via semantic segmentation in whole 3D CT scans. The algorithms demonstrate superior performance compared to algorithms based on conventional image analysis methods.

Application of environmental scanning electron microscopy to determine biological surface structure.

PubMed

Kirk, S E; Skepper, J N; Donald, A M

2009-02-01

The use of environmental scanning electron microscopy in biology is growing as more becomes understood about the advantages and limitations of the technique. These are discussed and we include new evidence about the effect of environmental scanning electron microscopy imaging on the viability of mammalian cells. We show that although specimen preparation for high-vacuum scanning electron microscopy introduces some artefacts, there are also challenges in the use of environmental scanning electron microscopy, particularly at higher resolutions. This suggests the two technologies are best used in combination. We have used human monocyte-derived macrophages as a test sample, imaging their complicated and delicate membrane ruffles and protrusions. We have also explored the possibility of using environmental scanning electron microscopy for dynamic experiments, finding that mammalian cells cannot be imaged and kept alive in the environmental scanning electron microscopy. The dehydration step in which the cell surface is exposed causes irreversible damage, probably via loss of membrane integrity during liquid removal in the specimen chamber. Therefore, mammalian cells should be imaged after fixation where possible to protect against damage as a result of chamber conditions.

Calibrating the ChemCam LIBS for Carbonate Minerals on Mars

DOE R&D Accomplishments Database

Wiens, Roger C.; Clegg, Samuel M.; Ollila, Ann M.; Barefield, James E.; Lanza, Nina; Newsom, Horton E.

2009-01-01

The ChemCam instrument suite on board the NASA Mars Science Laboratory (MSL) rover includes the first LIBS instrument for extraterrestrial applications. Here we examine carbonate minerals in a simulated martian environment using the LIDS technique in order to better understand the in situ signature of these materials on Mars. Both chemical composition and rock type are determined using multivariate analysis (MVA) techniques. Composition is confirmed using scanning electron microscopy (SEM) techniques. Our initial results suggest that ChemCam can recognize and differentiate between carbonate materials on Mars.

Infrared spectroscopy of molecular submonolayers on surfaces by infrared scanning tunneling microscopy: tetramantane on Au111.

PubMed

Pechenezhskiy, Ivan V; Hong, Xiaoping; Nguyen, Giang D; Dahl, Jeremy E P; Carlson, Robert M K; Wang, Feng; Crommie, Michael F

2013-09-20

We have developed a new scanning-tunneling-microscopy-based spectroscopy technique to characterize infrared (IR) absorption of submonolayers of molecules on conducting crystals. The technique employs a scanning tunneling microscope as a precise detector to measure the expansion of a molecule-decorated crystal that is irradiated by IR light from a tunable laser source. Using this technique, we obtain the IR absorption spectra of [121]tetramantane and [123]tetramantane on Au(111). Significant differences between the IR spectra for these two isomers show the power of this new technique to differentiate chemical structures even when single-molecule-resolved scanning tunneling microscopy (STM) images look quite similar. Furthermore, the new technique was found to yield significantly better spectral resolution than STM-based inelastic electron tunneling spectroscopy, and to allow determination of optical absorption cross sections. Compared to IR spectroscopy of bulk tetramantane powders, infrared scanning tunneling microscopy (IRSTM) spectra reveal narrower and blueshifted vibrational peaks for an ordered tetramantane adlayer. Differences between bulk and surface tetramantane vibrational spectra are explained via molecule-molecule interactions.

Dental magnetic resonance imaging: making the invisible visible.

PubMed

Idiyatullin, Djaudat; Corum, Curt; Moeller, Steen; Prasad, Hari S; Garwood, Michael; Nixdorf, Donald R

2011-06-01

Clinical dentistry is in need of noninvasive and accurate diagnostic methods to better evaluate dental pathosis. The purpose of this work was to assess the feasibility of a recently developed magnetic resonance imaging (MRI) technique, called SWeep Imaging with Fourier Transform (SWIFT), to visualize dental tissues. Three in vitro teeth, representing a limited range of clinical conditions of interest, imaged using a 9.4T system with scanning times ranging from 100 seconds to 25 minutes. In vivo imaging of a subject was performed using a 4T system with a 10-minute scanning time. SWIFT images were compared with traditional two-dimensional radiographs, three-dimensional cone-beam computed tomography (CBCT) scanning, gradient-echo MRI technique, and histological sections. A resolution of 100 μm was obtained from in vitro teeth. SWIFT also identified the presence and extent of dental caries and fine structures of the teeth, including cracks and accessory canals, which are not visible with existing clinical radiography techniques. Intraoral positioning of the radiofrequency coil produced initial images of multiple adjacent teeth at a resolution of 400 μm. SWIFT MRI offers simultaneous three-dimensional hard- and soft-tissue imaging of teeth without the use of ionizing radiation. Furthermore, it has the potential to image minute dental structures within clinically relevant scanning times. This technology has implications for endodontists because it offers a potential method to longitudinally evaluate teeth where pulp and root structures have been regenerated. Copyright © 2011 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

Measurement of third-order nonlinear susceptibility tensor in InP using extended Z-scan technique with elliptical polarization

NASA Astrophysics Data System (ADS)

Oishi, Masaki; Shinozaki, Tomohisa; Hara, Hikaru; Yamamoto, Kazunuki; Matsusue, Toshio; Bando, Hiroyuki

2018-05-01

The elliptical polarization dependence of the two-photon absorption coefficient β in InP has been measured by the extended Z-scan technique for thick materials in the wavelength range from 1640 to 1800 nm. The analytical formula of the Z-scan technique has been extended with consideration of multiple reflections. The Z-scan results have been fitted very well by the formula and β has been evaluated accurately. The three independent elements of the third-order nonlinear susceptibility tensor in InP have also been determined accurately from the elliptical polarization dependence of β.

MMX-I: data-processing software for multimodal X-ray imaging and tomography

PubMed Central

Bergamaschi, Antoine; Medjoubi, Kadda; Messaoudi, Cédric; Marco, Sergio; Somogyi, Andrea

2016-01-01

A new multi-platform freeware has been developed for the processing and reconstruction of scanning multi-technique X-ray imaging and tomography datasets. The software platform aims to treat different scanning imaging techniques: X-ray fluorescence, phase, absorption and dark field and any of their combinations, thus providing an easy-to-use data processing tool for the X-ray imaging user community. A dedicated data input stream copes with the input and management of large datasets (several hundred GB) collected during a typical multi-technique fast scan at the Nanoscopium beamline and even on a standard PC. To the authors’ knowledge, this is the first software tool that aims at treating all of the modalities of scanning multi-technique imaging and tomography experiments. PMID:27140159

High Resolution Ultrasonic Method for 3D Fingerprint Recognizable Characteristics in Biometrics Identification

NASA Astrophysics Data System (ADS)

Maev, R. Gr.; Bakulin, E. Yu.; Maeva, A.; Severin, F.

Biometrics is a rapidly evolving scientific and applied discipline that studies possible ways of personal identification by means of unique biological characteristics. Such identification is important in various situations requiring restricted access to certain areas, information and personal data and for cases of medical emergencies. A number of automated biometric techniques have been developed, including fingerprint, hand shape, eye and facial recognition, thermographic imaging, etc. All these techniques differ in the recognizable parameters, usability, accuracy and cost. Among these, fingerprint recognition stands alone since a very large database of fingerprints has already been acquired. Also, fingerprints are key evidence left at a crime scene and can be used to indentify suspects. Therefore, of all automated biometric techniques, especially in the field of law enforcement, fingerprint identification seems to be the most promising. We introduce a newer development of the ultrasonic fingerprint imaging. The proposed method obtains a scan only once and then varies the C-scan gate position and width to visualize acoustic reflections from any appropriate depth inside the skin. Also, B-scans and A-scans can be recreated from any position using such data array, which gives the control over the visualization options. By setting the C-scan gate deeper inside the skin, distribution of the sweat pores (which are located along the ridges) can be easily visualized. This distribution should be unique for each individual so this provides a means of personal identification, which is not affected by any changes (accidental or intentional) of the fingers' surface conditions. This paper discusses different setups, acoustic parameters of the system, signal and image processing options and possible ways of 3-dimentional visualization that could be used as a recognizable characteristic in biometric identification.

Thallium myocardial perfusion scans for the assessment of right ventricular hypertrophy in patients with cystic fibrosis. A comparison with other noninvasive techniques

DOE Office of Scientific and Technical Information (OSTI.GOV)

Newth, C.J.; Corey, M.L.; Fowler, R.S.

1981-01-01

The incidence of right ventricular hypertrophy in 32 patients with cystic fibrosis was studied using thallium 201 (TI-201) myocardial perfusion scans, and compared with other noninvasive techniques including electrocardiography, vectorcardiography, and M-mode echocardiography. The patients (mean age, 17.3 yr; range, 7 to 33) had a wide range of clinical and pulmonary abnormalities (mean Shwachman-Kulczycki score, 66.6). In the total study group, TI-201 scans, like the vectorcardiograms and the M-mode echocardiograms, gave a surprisingly high proportion of positive predictions for right ventricular hypertrophy (RVH) (44%). The correlations with all other noninvasive methods were uniformly poor, so caution must be exercised inmore » using this technique to predict early RVH in order to follow the natural history of cor pulmonale in cystic fibrosis. At the time of the study, 6 patients had clinical evidence of right ventricular failure, and in this disease setting must have had RVH. In 3 patients, RVH was confirmed at autopsy, and it was successfully predicted by TI-201 scans in 5 of the 6 patients. The false negative scan may have been due to regional myocardial ischemia secondary to severe right ventricular failure. In contrast, the vectorcardiogram, using Fowler's new criteria, made a successful prediction of RVH in all 6 patients, and the electro cardiogram in only 3. Although the M-mode echocardiogram was abnormal in all patients, it would have predicted RVH (with increased right ventricular anterior wall thickness) in only 1 patient. We concluded that TI-201 myocardial perfusion cans are good at confirming RVH in cases with established right ventricular failure, but have no advantage over vectorcardiographic assessments, which are logistically easier to perform and carry no radiation risks.« less

Improving lateral resolution and image quality of optical coherence tomography by the multi-frame superresolution technique for 3D tissue imaging.

PubMed

Shen, Kai; Lu, Hui; Baig, Sarfaraz; Wang, Michael R

2017-11-01

The multi-frame superresolution technique is introduced to significantly improve the lateral resolution and image quality of spectral domain optical coherence tomography (SD-OCT). Using several sets of low resolution C-scan 3D images with lateral sub-spot-spacing shifts on different sets, the multi-frame superresolution processing of these sets at each depth layer reconstructs a higher resolution and quality lateral image. Layer by layer processing yields an overall high lateral resolution and quality 3D image. In theory, the superresolution processing including deconvolution can solve the diffraction limit, lateral scan density and background noise problems together. In experiment, the improved lateral resolution by ~3 times reaching 7.81 µm and 2.19 µm using sample arm optics of 0.015 and 0.05 numerical aperture respectively as well as doubling the image quality has been confirmed by imaging a known resolution test target. Improved lateral resolution on in vitro skin C-scan images has been demonstrated. For in vivo 3D SD-OCT imaging of human skin, fingerprint and retina layer, we used the multi-modal volume registration method to effectively estimate the lateral image shifts among different C-scans due to random minor unintended live body motion. Further processing of these images generated high lateral resolution 3D images as well as high quality B-scan images of these in vivo tissues.

Technical Considerations on Scanning and Image Analysis for Amyloid PET in Dementia.

PubMed

Akamatsu, Go; Ohnishi, Akihito; Aita, Kazuki; Ikari, Yasuhiko; Yamamoto, Yasuji; Senda, Michio

2017-01-01

Brain imaging techniques, such as computed tomography (CT), magnetic resonance imaging (MRI), single photon emission computed tomography (SPECT), and positron emission tomography (PET), can provide essential and objective information for the early and differential diagnosis of dementia. Amyloid PET is especially useful to evaluate the amyloid-β pathological process as a biomarker of Alzheimer's disease. This article reviews critical points about technical considerations on the scanning and image analysis methods for amyloid PET. Each amyloid PET agent has its own proper administration instructions and recommended uptake time, scan duration, and the method of image display and interpretation. In addition, we have introduced general scanning information, including subject positioning, reconstruction parameters, and quantitative and statistical image analysis. We believe that this article could make amyloid PET a more reliable tool in clinical study and practice.

Effects of foveal information processing

NASA Technical Reports Server (NTRS)

Harris, R. L., Sr.

1984-01-01

The scanning behavior of pilots must be understood so that cockpit displays can be assembled which will provide the most information accurately and quickly to the pilot. The results of seven years of collecting and analyzing pilot scanning data are summarized. The data indicate that pilot scanning behavior is: (1) subsconscious; (2) situation dependent; and (3) can be disrupted if pilots are forced to make conscious decisions. Testing techniques and scanning analysis techniques have been developed that are sensitive to pilot workload.

The use of the temporal scan statistic to detect methicillin-resistant Staphylococcus aureus clusters in a community hospital.

PubMed

Faires, Meredith C; Pearl, David L; Ciccotelli, William A; Berke, Olaf; Reid-Smith, Richard J; Weese, J Scott

2014-07-08

In healthcare facilities, conventional surveillance techniques using rule-based guidelines may result in under- or over-reporting of methicillin-resistant Staphylococcus aureus (MRSA) outbreaks, as these guidelines are generally unvalidated. The objectives of this study were to investigate the utility of the temporal scan statistic for detecting MRSA clusters, validate clusters using molecular techniques and hospital records, and determine significant differences in the rate of MRSA cases using regression models. Patients admitted to a community hospital between August 2006 and February 2011, and identified with MRSA>48 hours following hospital admission, were included in this study. Between March 2010 and February 2011, MRSA specimens were obtained for spa typing. MRSA clusters were investigated using a retrospective temporal scan statistic. Tests were conducted on a monthly scale and significant clusters were compared to MRSA outbreaks identified by hospital personnel. Associations between the rate of MRSA cases and the variables year, month, and season were investigated using a negative binomial regression model. During the study period, 735 MRSA cases were identified and 167 MRSA isolates were spa typed. Nine different spa types were identified with spa type 2/t002 (88.6%) the most prevalent. The temporal scan statistic identified significant MRSA clusters at the hospital (n=2), service (n=16), and ward (n=10) levels (P ≤ 0.05). Seven clusters were concordant with nine MRSA outbreaks identified by hospital staff. For the remaining clusters, seven events may have been equivalent to true outbreaks and six clusters demonstrated possible transmission events. The regression analysis indicated years 2009-2011, compared to 2006, and months March and April, compared to January, were associated with an increase in the rate of MRSA cases (P ≤ 0.05). The application of the temporal scan statistic identified several MRSA clusters that were not detected by hospital personnel. The identification of specific years and months with increased MRSA rates may be attributable to several hospital level factors including the presence of other pathogens. Within hospitals, the incorporation of the temporal scan statistic to standard surveillance techniques is a valuable tool for healthcare workers to evaluate surveillance strategies and aid in the identification of MRSA clusters.

Thermal conductivity profile determination in proton-irradiated ZrC by spatial and frequency scanning thermal wave methods

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jensen, C.; Department of Mechanical and Aerospace Engineering, Utah State University, Logan, Utah 84322; Chirtoc, M.

2013-10-07

Using complementary thermal wave methods, the irradiation damaged region of zirconium carbide (ZrC) is characterized by quantifiably profiling the thermophysical property degradation. The ZrC sample was irradiated by a 2.6 MeV proton beam at 600 °C to a dose of 1.75 displacements per atom. Spatial scanning techniques including scanning thermal microscopy (SThM), lock-in infrared thermography (lock-in IRT), and photothermal radiometry (PTR) were used to directly map the in-depth profile of thermal conductivity on a cross section of the ZrC sample. The advantages and limitations of each system are discussed and compared, finding consistent results from all techniques. SThM provides themore » best resolution finding a very uniform thermal conductivity envelope in the damaged region measuring ∼52 ± 2 μm deep. Frequency-based scanning PTR provides quantification of the thermal parameters of the sample using the SThM measured profile to provide validation of a heating model. Measured irradiated and virgin thermal conductivities are found to be 11.9 ± 0.5 W m{sup −1} K{sup −1} and 26.7 ±1 W m{sup −1} K{sup −1}, respectively. A thermal resistance evidenced in the frequency spectra of the PTR results was calculated to be (1.58 ± 0.1) × 10{sup −6} m{sup 2} K W{sup −1}. The measured thermal conductivity values compare well with the thermal conductivity extracted from the SThM calibrated signal and the spatially scanned PTR. Combined spatial and frequency scanning techniques are shown to provide a valuable, complementary combination for thermal property characterization of proton-irradiated ZrC. Such methodology could be useful for other studies of ion-irradiated materials.« less

Application of Terrestrial Laser Scanning to Study the Geometry of Slender Objects

NASA Astrophysics Data System (ADS)

Muszynski, Zbigniew; Milczarek, Wojciech

2017-12-01

Slender objects are a special group among the many types of industrial structures. These objects are characterized by a considerable height which is at least several times bigger than the diameter of the base. Mainly various types of industrial chimneys, as well as truss masts, towers, radio and television towers and also windmill columns belong to this group. During their operation slender objects are exposed to a number of unfavourable factors. For this reason, these objects require regular inspection, including geodetic measurements. In the paper the results of geodetic control of geometry of industrial chimney with a height of 120 m has been presented. The measurements were made by means of terrestrial laser scanning technique under rather unfavourable conditions (at night, during snowfall, with low air temperature) which allowed to verify the real usefulness and accuracy of this technique in engineering practice. On the basis of point cloud, the values of deviations from the vertical for main axis of the chimney have been calculated. Using point cloud, the selected horizontal cross sections of chimney were analysed and were compared with the archival geodetic documentation. On this basis the final conclusions about the advantages and limitations of the using of terrestrial laser scanning technique for the control of geometry of high industrial chimneys have been formulated.

Australian Red Dune Sand: A Potential Martian Regolith Analog

NASA Technical Reports Server (NTRS)

Kuhlman, K. R.; Marshall, J.; Evans, N. D.; Luttge, A.

2001-01-01

To demonstrate the potential scientific and technical merits of in situ microscopy on Mars, we analyzed a possible Martian regolith analog - an acolian red dune sand from the central Australian desert (near Mt. Olga). This sand was chosen for its ubiquitous red coating and the desert environment in which is it found. Grains of this sand were analyzed using a variety of microanalytical techniques. A database of detailed studies of such terrestrial analogs would assist the study of geological and astrobiological specimens in future missions to Mars. Potential instrument concepts for in situ deployment on Mars include local electrode atom probe nanoanalysis (LEAP), vertical scanning white light interferometry (VSWLI), scanning electron microscopies, energy dispersive x-ray microanalysis (EDX), atomic force microscopy (AFM) and X-ray diffraction (XRD). While in situ deployment of these techniques is many years away, ground-based studies using these analytical techniques extend our understanding of the data obtained from instruments to be flown in the near future.

Comprehensive Analysis of LC/MS Data Using Pseudocolor Plots

NASA Astrophysics Data System (ADS)

Crutchfield, Christopher A.; Olson, Matthew T.; Gourgari, Evgenia; Nesterova, Maria; Stratakis, Constantine A.; Yergey, Alfred L.

2013-02-01

We have developed new applications of the pseudocolor plot for the analysis of LC/MS data. These applications include spectral averaging, analysis of variance, differential comparison of spectra, and qualitative filtering by compound class. These applications have been motivated by the need to better understand LC/MS data generated from analysis of human biofluids. The examples presented use data generated to profile steroid hormones in urine extracts from a Cushing's disease patient relative to a healthy control, but are general to any discovery-based scanning mass spectrometry technique. In addition to new visualization techniques, we introduce a new metric of variance: the relative maximum difference from the mean. We also introduce the concept of substructure-dependent analysis of steroid hormones using precursor ion scans. These new analytical techniques provide an alternative approach to traditional untargeted metabolomics workflow. We present an approach to discovery using MS that essentially eliminates alignment or preprocessing of spectra. Moreover, we demonstrate the concept that untargeted metabolomics can be achieved using low mass resolution instrumentation.

Controllable self-induced passivation of hybrid lead iodide perovskites toward high performance solar cells.

PubMed

Chen, Qi; Zhou, Huanping; Song, Tze-Bin; Luo, Song; Hong, Ziruo; Duan, Hsin-Sheng; Dou, Letian; Liu, Yongsheng; Yang, Yang

2014-07-09

To improve the performance of the polycrystalline thin film devices, it requires a delicate control of its grain structures. As one of the most promising candidates among current thin film photovoltaic techniques, the organic/inorganic hybrid perovskites generally inherit polycrystalline nature and exhibit compositional/structural dependence in regard to their optoelectronic properties. Here, we demonstrate a controllable passivation technique for perovskite films, which enables their compositional change, and allows substantial enhancement in corresponding device performance. By releasing the organic species during annealing, PbI2 phase is presented in perovskite grain boundaries and at the relevant interfaces. The consequent passivation effects and underlying mechanisms are investigated with complementary characterizations, including scanning electron microscopy (SEM), X-ray diffraction (XRD), time-resolved photoluminescence decay (TRPL), scanning Kelvin probe microscopy (SKPM), and ultraviolet photoemission spectroscopy (UPS). This controllable self-induced passivation technique represents an important step to understand the polycrystalline nature of hybrid perovskite thin films and contributes to the development of perovskite solar cells judiciously.

Imaging in syndesmotic injury: a systematic literature review.

PubMed

Krähenbühl, Nicola; Weinberg, Maxwell W; Davidson, Nathan P; Mills, Megan K; Hintermann, Beat; Saltzman, Charles L; Barg, Alexej

2018-05-01

To give a systematic overview of current diagnostic imaging options for assessment of the distal tibio-fibular syndesmosis. A systematic literature search across the following sources was performed: PubMed, ScienceDirect, Google Scholar, and SpringerLink. Forty-two articles were included and subdivided into three groups: group one consists of studies using conventional radiographs (22 articles), group two includes studies using computed tomography (CT) scans (15 articles), and group three comprises studies using magnet resonance imaging (MRI, 9 articles).The following data were extracted: imaging modality, measurement method, number of participants and ankles included, average age of participants, sensitivity, specificity, and accuracy of the measurement technique. The Quality Assessment of Diagnostic Accuracy Studies 2 (QUADAS-2) tool was used to assess the methodological quality. The three most common techniques used for assessment of the syndesmosis in conventional radiographs are the tibio-fibular clear space (TFCS), the tibio-fibular overlap (TFO), and the medial clear space (MCS). Regarding CT scans, the tibio-fibular width (axial images) was most commonly used. Most of the MRI studies used direct assessment of syndesmotic integrity. Overall, the included studies show low probability of bias and are applicable in daily practice. Conventional radiographs cannot predict syndesmotic injuries reliably. CT scans outperform plain radiographs in detecting syndesmotic mal-reduction. Additionally, the syndesmotic interval can be assessed in greater detail by CT. MRI measurements achieve a sensitivity and specificity of nearly 100%; however, correlating MRI findings with patients' complaints is difficult, and utility with subtle syndesmotic instability needs further investigation. Overall, the methodological quality of these studies was satisfactory.

Some failure modes and analysis techniques for terrestrial solar cell modules

NASA Technical Reports Server (NTRS)

Shumka, A.; Stern, K. H.

1978-01-01

Analysis data are presented on failed/defective silicon solar cell modules of various types and produced by different manufacturers. The failure mode (e.g., internal short and open circuits, output power degradation, isolation resistance degradation, etc.) are discussed in detail and in many cases related to the type of technology used in the manufacture of the modules; wherever applicable, appropriate corrective actions are recommended. Consideration is also given to some failure analysis techniques that are applicable to such modules, including X-ray radiography, capacitance measurement, cell shunt resistance measurement by the shadowing technique, steady-state illumination test station for module performance illumination, laser scanning techniques, and the SEM.

An optimized protocol for handling and processing fragile acini cultured with the hanging drop technique.

PubMed

Snyman, Celia; Elliott, Edith

2011-12-15

The hanging drop three-dimensional culture technique allows cultivation of functional three-dimensional mammary constructs without exogenous extracellular matrix. The fragile acini are, however, difficult to preserve during processing steps for advanced microscopic investigation. We describe adaptations to the protocol for handling of hanging drop cultures to include investigation using confocal, scanning, and electron microscopy, with minimal loss of cell culture components. Copyright © 2011 Elsevier Inc. All rights reserved.

Teaching Raster GIS Operations with Spreadsheets.

ERIC Educational Resources Information Center

Raubal, Martin; Gaupmann, Bernhard; Kuhn, Werner

1997-01-01

Defines raster technology in its relationship to geographic information systems and notes that it is typically used with the application of remote sensing techniques and scanning devices. Discusses the role of spreadsheets in a raster model, and describes a general approach based on spreadsheets. Includes six computer-generated illustrations. (MJP)

Datasets, Technologies and Products from the NASA/NOAA Electronic Theater 2002

NASA Technical Reports Server (NTRS)

Hasler, A. Fritz; Starr, David (Technical Monitor)

2001-01-01

An in depth look at the Earth Science datasets used in the Etheater Visualizations will be presented. This will include the satellite orbits, platforms, scan patterns, the size, temporal and spatial resolution, and compositing techniques used to obtain the datasets as well as the spectral bands utilized.

Television Sweep Circuits and Picture Signal Path; Radio and Television Service--Advanced: 9787.02.

ERIC Educational Resources Information Center

Dade County Public Schools, Miami, FL.

This course outline is designed to give students a working knowledge of radio and television theory and servicing techniques. Course content includes goals, specific block objectives, resistance-capacitance circuit characteristics, sawtooth generators sawtooth generator control and production of scanning waveforms, deflection systems, composite…

Whole brain analysis of postmortem density changes of grey and white matter on computed tomography by statistical parametric mapping.

PubMed

Nishiyama, Yuichi; Kanayama, Hidekazu; Mori, Hiroshi; Tada, Keiji; Yamamoto, Yasushi; Katsube, Takashi; Takeshita, Haruo; Kawakami, Kazunori; Kitagaki, Hajime

2017-06-01

This study examined the usefulness of statistical parametric mapping (SPM) for investigating postmortem changes on brain computed tomography (CT). This retrospective study included 128 patients (23 - 100 years old) without cerebral abnormalities who underwent unenhanced brain CT before and after death. The antemortem CT (AMCT) scans and postmortem CT (PMCT) scans were spatially normalized using our original brain CT template, and postmortem changes of CT values (in Hounsfield units; HU) were analysed by the SPM technique. Compared with AMCT scans, 58.6 % and 98.4 % of PMCT scans showed loss of the cerebral sulci and an unclear grey matter (GM)-white matter (WM) interface, respectively. SPM analysis revealed a significant decrease in cortical GM density within 70 min after death on PMCT scans, suggesting cytotoxic brain oedema. Furthermore, there was a significant increase in the density of the WM, lenticular nucleus and thalamus more than 120 min after death. The SPM technique demonstrated typical postmortem changes on brain CT scans, and revealed that the unclear GM-WM interface on early PMCT scans is caused by a rapid decrease in cortical GM density combined with a delayed increase in WM density. SPM may be useful for assessment of whole brain postmortem changes. • The original brain CT template achieved successful normalization of brain morphology. • Postmortem changes in the brain were independent of sex. • Cortical GM density decreased rapidly after death. • WM and deep GM densities increased following cortical GM density change. • SPM could be useful for assessment of whole brain postmortem changes.

Visualisation of urban airborne laser scanning data with occlusion images

NASA Astrophysics Data System (ADS)

Hinks, Tommy; Carr, Hamish; Gharibi, Hamid; Laefer, Debra F.

2015-06-01

Airborne Laser Scanning (ALS) was introduced to provide rapid, high resolution scans of landforms for computational processing. More recently, ALS has been adapted for scanning urban areas. The greater complexity of urban scenes necessitates the development of novel methods to exploit urban ALS to best advantage. This paper presents occlusion images: a novel technique that exploits the geometric complexity of the urban environment to improve visualisation of small details for better feature recognition. The algorithm is based on an inversion of traditional occlusion techniques.

A scanning electron microscope technique for studying the sclerites of Cichlidogyrus.

PubMed

Fannes, Wouter; Vanhove, Maarten P M; Huyse, Tine; Paladini, Giuseppe

2015-05-01

The genus Cichlidogyrus (Monogenea: Ancyrocephalidae) includes more than 90 species, most of which are gill parasites of African cichlid fishes. Cichlidogyrus has been studied extensively in recent years, but scanning electron microscope (SEM) investigations of the isolated hard parts have not yet been undertaken. In this paper, we describe a method for isolating and scanning the sclerites of individual Cichlidogyrus worms. Twenty-year-old, formol-fixed specimens of Cichlidogyrus casuarinus were subjected to proteinase K digestion in order to release the sclerites from the surrounding soft tissues. SEM micrographs of the haptoral sclerites and the male copulatory organ are presented. The ability to digest formol-fixed specimens makes this method a useful tool for the study of historical museum collections.

The smiling scan technique: Facially driven guided surgery and prosthetics.

PubMed

Pozzi, Alessandro; Arcuri, Lorenzo; Moy, Peter K

2018-04-11

To introduce a proof of concept technique and new integrated workflow to optimize the functional and esthetic outcome of the implant-supported restorations by means of a 3-dimensional (3D) facially-driven, digital assisted treatment plan. The Smiling Scan technique permits the creation of a virtual dental patient (VDP) showing a broad smile under static conditions. The patient is exposed to a cone beam computed tomography scan (CBCT), displaying a broad smile for the duration of the examination. Intraoral optical surface scanning (IOS) of the dental and soft tissue anatomy or extraoral optical surface scanning (EOS) of the study casts are achieved. The superimposition of the digital imaging and communications in medicine (DICOM) files with standard tessellation language (STL) files is performed using the virtual planning software program permitting the creation of a VDP. The smiling scan is an effective, easy to use, and low-cost technique to develop a more comprehensive and simplified facially driven computer-assisted treatment plan, allowing a prosthetically driven implant placement and the delivery of an immediate computer aided design (CAD) computer aided manufacturing (CAM) temporary fixed dental prostheses (CAD/CAM technology). Copyright © 2018 Japan Prosthodontic Society. Published by Elsevier Ltd. All rights reserved.

Electrochemical etching technique of platinum-iridium tips for scanning tunneling microscopy

NASA Astrophysics Data System (ADS)

Herrera, Oscar

The scanning tunneling microscope (STM) allows researchers to investigate atomic and molecular structures and properties of nanomaterials. Through the quantum tunneling effect a charge is transferred between the surface of the material and a Platinum-Iridium (Pt-Ir) tip. The production of Pt-Ir tips by electrochemical etching (ECE) has been developed as an alternative technique, to achieve enhanced scanned images of samples, in contrast to the standard mechanical method (SMM). The sharpness apex structure is an essential feature during scanning in order to provide reliable data. We generated a control group of tips by the SMM technique and another group by the ECE technique to investigate the resolution effectiveness in scanning of graphite. The etching of the tips was produced using an auto-variable transformer running a 30 V AC in a 1.5 and 4.0 M CaCl2 solution. The scanning of the graphite surface was conducted at 7x7 nm image width, 0.2 seconds time/line, 256 points/line and 0.05 V for tip voltage. ECE etched tips displayed consistent image resolution, and the sharpness of the tip apex was generally uniform.

Material properties of viral nanocages explored by atomic force microscopy.

PubMed

van Rosmalen, Mariska G M; Roos, Wouter H; Wuite, Gijs J L

2015-01-01

Single-particle nanoindentation by atomic force microscopy (AFM) is an emergent technique to characterize the material properties of nano-sized proteinaceous systems. AFM uses a very small tip attached to a cantilever to scan the surface of the substrate. As a result of the sensitive feedback loop of AFM, the force applied by the tip on the substrate during scanning can be controlled and monitored. By accurately controlling this scanning force, topographical maps of fragile substrates can be acquired to study the morphology of the substrate. In addition, mechanical properties of the substrate like stiffness and breaking point can be determined by using the force spectroscopy capability of AFM. Here we discuss basics of AFM operation and how this technique is used to determine the structure and mechanical properties of protein nanocages, in particular viral particles. Knowledge of morphology as well as mechanical properties is essential for understanding viral life cycles, including genome packaging, capsid maturation, and uncoating, but also contributes to the development of diagnostics, vaccines, imaging modalities, and targeted therapeutic devices based on viruslike particles.

X-ray backscatter imaging for radiography by selective detection and snapshot: Evolution, development, and optimization

NASA Astrophysics Data System (ADS)

Shedlock, Daniel

Compton backscatter imaging (CBI) is a single-sided imaging technique that uses the penetrating power of radiation and unique interaction properties of radiation with matter to image subsurface features. CBI has a variety of applications that include non-destructive interrogation, medical imaging, security and military applications. Radiography by selective detection (RSD), lateral migration radiography (LMR) and shadow aperture backscatter radiography (SABR) are different CBI techniques that are being optimized and developed. Radiography by selective detection (RSD) is a pencil beam Compton backscatter imaging technique that falls between highly collimated and uncollimated techniques. Radiography by selective detection uses a combination of single- and multiple-scatter photons from a projected area below a collimation plane to generate an image. As a result, the image has a combination of first- and multiple-scatter components. RSD techniques offer greater subsurface resolution than uncollimated techniques, at speeds at least an order of magnitude faster than highly collimated techniques. RSD scanning systems have evolved from a prototype into near market-ready scanning devices for use in a variety of single-sided imaging applications. The design has changed to incorporate state-of-the-art detectors and electronics optimized for backscatter imaging with an emphasis on versatility, efficiency and speed. The RSD system has become more stable, about 4 times faster, and 60% lighter while maintaining or improving image quality and contrast over the past 3 years. A new snapshot backscatter radiography (SBR) CBI technique, shadow aperture backscatter radiography (SABR), has been developed from concept and proof-of-principle to a functional laboratory prototype. SABR radiography uses digital detection media and shaded aperture configurations to generate near-surface Compton backscatter images without scanning, similar to how transmission radiographs are taken. Finally, a more inclusive theory of the factors affecting CBI contrast generation has tied together the past work of LMR with the more recent research in RSD. A variety of factors that induce changes in the backscatter photon field intensity (resulting in contrast changes in images) include: changes in the electron density field, attenuation changes along the entrance and exit paths, changes in the relative geometric positioning of the target, feature, illumination beam, and detectors. Understanding the interplay of how changes in each of these factors affects image contrast becomes essential to utilizing and optimizing RSD for different applications.

Pencil beam characteristics of the next-generation proton scanning gantry of PSI: design issues and initial commissioning results

NASA Astrophysics Data System (ADS)

Pedroni, E.; Meer, D.; Bula, C.; Safai, S.; Zenklusen, S.

2011-07-01

In this paper we report on the main design features, on the realization process and on selected first results of the initial commissioning of the new Gantry 2 of PSI for the delivery of proton therapy with new advanced pencil beam scanning techniques. We present briefly the characteristics of the new gantry system with main emphasis on the beam optics, on the characterization of the pencil beam used for scanning and on the performance of the scanning system. The idea is to give an overview of the major components of the whole system. The main long-term technical goal of the new equipment of Gantry 2 is to expand the use of pencil beam scanning to the whole spectrum of clinical indications including moving targets. We report here on the initial experience and problems encountered in the development of the system with selected preliminary results of the ongoing commissioning of Gantry 2.

Development of scanning graphene Hall probes for magnetic microscopy

NASA Astrophysics Data System (ADS)

Schaefer, Brian T.; Wang, Lei; McEuen, Paul L.; Nowack, Katja C.

We discuss our progress on developing scanning Hall probes fabricated from hexagonal boron nitride (hBN)-encapsulated graphene, with the goal to image magnetic fields with submicron resolution. In contrast to scanning superconducting quantum interference device (SQUID) microscopy, this technique is compatible with a large applied magnetic field and not limited to cryogenic temperatures. The field sensitivity of a Hall probe depends inversely on carrier density, while the primary source of noise in the measurement is Johnson noise originating from the device resistance. hBN-encapsulated graphene demonstrates high carrier mobility at low carrier densities, therefore making it an ideal material for sensitive Hall probes. Furthermore, engineering the dielectric environment of graphene by encapsulating in hBN reduces low-frequency charge noise and disorder from the substrate. We outline our plans for adapting these devices for scanning, including characterization of the point spread function with a scanned current loop and fabrication of a deep-etched structure that enables positioning the sensitive area within 100 nanometers of the sample surface.

X-ray microanalysis in the scanning electron microscope.

PubMed

Roomans, Godfried M; Dragomir, Anca

2014-01-01

X-ray microanalysis conducted using the scanning electron microscope is a technique that allows the determination of chemical elements in bulk or semi-thick specimens. The lowest concentration of an element that can be detected is in the order of a few mmol/kg or a few hundred parts per million, and the smallest amount is in the order of 10(-18) g. The spatial resolution of the analysis depends on the thickness of the specimen. For biological specimen analysis, care must be taken to prevent displacement/loss of the element of interest (usually ions). Protocols are presented for the processing of frozen-hydrated and freeze-dried specimens, as well as for the analysis of small volumes of fluid, cell cultures, and other specimens. Aspects of qualitative and quantitative analysis are covered, including limitations of the technique.

X-ray microanalysis in the scanning electron microscope.

PubMed

Roomans, Godfried M; Dragomir, Anca

2007-01-01

X-ray microanalysis conducted using the scanning electron microscope is a technique that allows the determination of chemical elements in bulk or semithick specimens. The lowest concentration of an element that can be detected is in the order of a few mmol/kg or a few hundred parts per million, and the smallest amount is in the order of 10(-18) g. The spatial resolution of the analysis depends on the thickness of the specimen. For biological specimen analysis, care must be taken to prevent displacement/loss of the element of interest (usually ions). Protocols are presented for the processing of frozen-hydrated and freeze-dried specimens, as well as for the analysis of small volumes of fluid, cell cultures and other specimens. Aspects of qualitative and quantitative analysis are covered, including limitations of the technique.

Machine processing of remotely sensed data; Proceedings of the Conference, Purdue University, West Lafayette, Ind., October 16-18, 1973

NASA Technical Reports Server (NTRS)

1973-01-01

Topics discussed include the management and processing of earth resources information, special-purpose processors for the machine processing of remotely sensed data, digital image registration by a mathematical programming technique, the use of remote-sensor data in land classification (in particular, the use of ERTS-1 multispectral scanning data), the use of remote-sensor data in geometrical transformations and mapping, earth resource measurement with the aid of ERTS-1 multispectral scanning data, the use of remote-sensor data in the classification of turbidity levels in coastal zones and in the identification of ecological anomalies, the problem of feature selection and the classification of objects in multispectral images, the estimation of proportions of certain categories of objects, and a number of special systems and techniques. Individual items are announced in this issue.

Investigation of MR scanning, image registration, and image processing techniques to visualize cortical veins for neurosurgery

NASA Astrophysics Data System (ADS)

Noordmans, Herke J.; Rutten, G. J. M.; Willems, Peter W. A.; Hoogduin, J.; Viergever, Max A.

2001-01-01

The visualization of brain vessels on the cortex helps the neurosurgeon in two ways: To avoid blood vessels when specifying the trepanation entry, and to overcome errors in the surgical navigation system due to brain shift. We compared 3D T1 MR, 3D T1 MR with gadolinium contrast, MR venography and MR phase contrast angiography as scanning techniques, mutual information as registration technique, and thresholding and multi-vessel enhancement as image processing techniques. We evaluated the volume rendered results based on their quality and correspondence with photos took during surgery. It appears that with 3D T1 MR scans, gadolinium is required to show cortical veins. The visibility of small cortical veins is strongly enhanced by subtracting a 3D T1 MR baseline scan, which should be registered to the scan with gadolinium contrast, even when the scans are made during the same session. Multi-vessel enhancement helps to clarify the view on small vessels by reducing the noise level, but strikingly does not reveal more. MR venography does show intracerebral veins with high detail, but is, as is, unsuited to show cortical veins due to the low contrast with CSF. MR phase contrast angiography can perform equally well as the subtraction technique, but its quality seems to show more inter-patient variability.

Optical fabrication and testing; Proceedings of the Meeting, Singapore, Oct. 22-27, 1990

NASA Astrophysics Data System (ADS)

Lorenzen, Manfred; Campbell, Duncan R.; Johnson, Craig W.

1991-03-01

Various papers on optical fabrication and testing are presented. Individual topics addressed include: interferometry with laser diodes, new methods for economic production of prisms and lenses, interferometer accuracy and precision, optical testing with wavelength scanning interferometer, digital Talbot interferometer, high-sensitivity interferometric technique for strain measurements, absolute interferometric testing of spherical surfaces, contouring using gratings created on an LCD panel, three-dimensional inspection using laser-based dynamic fringe projection, noncontact optical microtopography, laser scan microscope and infrared laser scan microscope, photon scanning tunneling microscopy. Also discussed are: combination-matching problems in the layout design of minilaser rangefinder, design and testing of a cube-corner array for laser ranging, mode and far-field pattern of diode laser-phased arrays, new glasses for optics and optoelectronics, optical properties of Li-doped ZnO films, application and machining of Zerodur for optical purposes, finish machining of optical components in mass production.

Airline pilot scan patterns during simulated ILS approaches

NASA Technical Reports Server (NTRS)

Spady, A. A., Jr.

1978-01-01

A series of instrument landing system approaches were conducted using seven airline-rated Boeing 737 pilots in a Federal Aviation Administration qualified simulator. The test matrix included both manual and coupled approaches with and without atmospheric turbulence in Category II visibility conditions. A nonintrusive oculometer system was used to track the pilot eye-point-of-regard throughout the approach. The results indicate that, in general, the pilots use different scan techniques for the manual and coupled conditions and that the introduction of atmospheric turbulence does not greatly affect the scan behavior in either case. The pilots consistently ranked the instruments in terms of most used to least used. The ranking obtained from the oculometer data agrees with the pilot ranking for the flight director and airspeed, the most important instruments. However, the pilots apparently ranked the other instruments in terms of their concern for information rather than according to their actual scanning behavior.

Optical fabrication and testing; Proceedings of the Meeting, Singapore, Oct. 22-27, 1990

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lorenzen, M.; Campbell, D.R.; Johnson, C.W.

1991-01-01

Various papers on optical fabrication and testing are presented. Individual topics addressed include: interferometry with laser diodes, new methods for economic production of prisms and lenses, interferometer accuracy and precision, optical testing with wavelength scanning interferometer, digital Talbot interferometer, high-sensitivity interferometric technique for strain measurements, absolute interferometric testing of spherical surfaces, contouring using gratings created on an LCD panel, three-dimensional inspection using laser-based dynamic fringe projection, noncontact optical microtopography, laser scan microscope and infrared laser scan microscope, photon scanning tunneling microscopy. Also discussed are: combination-matching problems in the layout design of minilaser rangefinder, design and testing of a cube-corner arraymore » for laser ranging, mode and far-field pattern of diode laser-phased arrays, new glasses for optics and optoelectronics, optical properties of Li-doped ZnO films, application and machining of Zerodur for optical purposes, finish machining of optical components in mass production.« less

Motor unit activity within the depth of the masseter characterized by an adapted scanning EMG technique.

PubMed

van Dijk, J P; Eiglsperger, U; Hellmann, D; Giannakopoulos, N N; McGill, K C; Schindler, H J; Lapatki, B G

2016-09-01

To study motor unit activity in the medio-lateral extension of the masseter using an adapted scanning EMG technique that allows studying the territories of multiple motor units (MUs) in one scan. We studied the m. masseter of 10 healthy volunteers in whom two scans were performed. A monopolar scanning needle and two pairs of fine-wire electrodes were inserted into the belly of the muscle. The signals of the fine wire electrodes were decomposed into the contribution of single MUs and used as a trigger for the scanning needle. In this manner multiple MU territory scans were obtained simultaneously. We determined 161 MU territories. The maximum number of territories obtained in one scan was 15. The median territory size was 4.0mm. Larger and smaller MU territories were found throughout the muscle. The presented technique showed its feasibility in obtaining multiple MU territories in one scan. MUs were active throughout the depth of the muscle. The distribution of electrical and anatomical size of MUs substantiates the heterogeneous distribution of MUs throughout the muscle volume. This distributed activity may be of functional significance for the stabilization of the muscle during force generation. Copyright © 2016 International Federation of Clinical Neurophysiology. All rights reserved.

Measuring Roughnesses Of Optical Surfaces

NASA Technical Reports Server (NTRS)

Coulter, Daniel R.; Al-Jumaily, Gahnim A.; Raouf, Nasrat A.; Anderson, Mark S.

1994-01-01

Report discusses use of scanning tunneling microscopy and atomic force microscopy to measure roughnesses of optical surfaces. These techniques offer greater spatial resolution than other techniques. Report notes scanning tunneling microscopes and atomic force microscopes resolve down to 1 nm.

Plant cell wall characterization using scanning probe microscopy techniques

PubMed Central

Yarbrough, John M; Himmel, Michael E; Ding, Shi-You

2009-01-01

Lignocellulosic biomass is today considered a promising renewable resource for bioenergy production. A combined chemical and biological process is currently under consideration for the conversion of polysaccharides from plant cell wall materials, mainly cellulose and hemicelluloses, to simple sugars that can be fermented to biofuels. Native plant cellulose forms nanometer-scale microfibrils that are embedded in a polymeric network of hemicelluloses, pectins, and lignins; this explains, in part, the recalcitrance of biomass to deconstruction. The chemical and structural characteristics of these plant cell wall constituents remain largely unknown today. Scanning probe microscopy techniques, particularly atomic force microscopy and its application in characterizing plant cell wall structure, are reviewed here. We also further discuss future developments based on scanning probe microscopy techniques that combine linear and nonlinear optical techniques to characterize plant cell wall nanometer-scale structures, specifically apertureless near-field scanning optical microscopy and coherent anti-Stokes Raman scattering microscopy. PMID:19703302

Applicability of confocal laser scanning microscopy for evaluation and monitoring of cutaneous wound healing

NASA Astrophysics Data System (ADS)

Lange-Asschenfeldt, Susanne; Bob, Adrienne; Terhorst, Dorothea; Ulrich, Martina; Fluhr, Joachim; Mendez, Gil; Roewert-Huber, Hans-Joachim; Stockfleth, Eggert; Lange-Asschenfeldt, Bernhard

2012-07-01

There is a high demand for noninvasive imaging techniques for wound assessment. In vivo reflectance confocal laser scanning microscopy (CLSM) represents an innovative optical technique for noninvasive evaluation of normal and diseased skin in vivo at near cellular resolution. This study was designed to test the feasibility of CLSM for noninvasive analysis of cutaneous wound healing in 15 patients (7 male/8 female), including acute and chronic, superficial and deep dermal skin wounds. A commercially available CLSM system was used for the assessment of wound bed and wound margins in order to obtain descriptive cellular and morphological parameters of cutaneous wound repair noninvasively and over time. CLSM was able to visualize features of cutaneous wound repair in epidermal and superficial dermal wounds, including aspects of inflammation, neovascularisation, and tissue remodelling in vivo. Limitations include the lack of mechanic fixation of the optical system on moist surfaces restricting the analysis of chronic skin wounds to the wound margins, as well as a limited optical resolution in areas of significant slough formation. By describing CLSM features of cutaneous inflammation, vascularisation, and epithelialisation, the findings of this study support the role of CLSM in modern wound research and management.

An Ultrasonic Scanning Technique for In-Situ `Bowing' Measurement of Prototype Fast Breeder Reactor Fuel Sub-Assembly

NASA Astrophysics Data System (ADS)

Swaminathan, K.; Asokane, C.; Sylvia, J. I.; Kalyanasundaram, P.; Swaminathan, P.

2012-02-01

An ultrasonic under-sodium scanner has been developed for deployment in Prototype Fast Breeder Reactor (PFBR) which is in advanced stage of construction at Kalpakkam, India. Its purpose is to scan the above-core plenum for detection, if any, of displacement of sub-assemblies. During its burn-up in the reactor, the head of a Fuel Sub-Assembly (FSA) may undergo a lateral shift from its original position (called `bowing') due to the fast neutron induced damage on its structural material. A simple scanning technique has been developed for measuring the extent of bowing in-situ. This paper describes a PC-controlled mock-up of the scanner used to implement the scanning technique and the results obtained of scanning a mock-up FSA head under water. The details of the liquid-sodium proof transducer developed for use in the PFBR scanner and its performance are also discussed.

SU-F-I-32: Organ Doses from Pediatric Head CT Scan

DOE Office of Scientific and Technical Information (OSTI.GOV)

Liu, H; Liu, Q; Qiu, J

Purpose: To evaluate the organ doses of pediatric patients who undergoing head CT scan using Monte Carlo (MC) simulation and compare it with measurements in anthropomorphic child phantom.. Methods: A ten years old children voxel phantom was developed from CT images, the voxel size of the phantom was 2mm*2mm*2mm. Organ doses from head CT scan were simulated using MCNPX software, 180 detectors were placed in the voxel phantom to tally the doses of the represented tissues or organs. When performing the simulation, 120 kVp and 88 mA were selected as the scan parameters. The scan range covered from the topmore » of the head to the end of the chain, this protocol was used at CT simulator for radiotherapy. To validate the simulated results, organ doses were measured with radiophotoluminescence (RPL) detectors, placed in the 28 organs of the 10 years old CIRS ATOM phantom. Results: The organ doses results matched well between MC simulation and phantom measurements. The eyes dose was showed to be as expected the highest organ dose: 28.11 mGy by simulation and 27.34 mGy by measurement respectively. Doses for organs not included in the scan volume were much lower than those included in the scan volume, thymus doses were observed more than 10 mGy due the CT protocol for radiotherapy covered more body part than routine head CT scan. Conclusion: As the eyes are superficial organs, they may receive the highest radiation dose during the CT scan. Considering the relatively high radio sensitivity, using shielding material or organ based tube current modulation technique should be encouraged to reduce the eye radiation risks. Scan range was one of the most important factors that affects the organ doses during the CT scan. Use as short as reasonably possible scan range should be helpful to reduce the patient radiation dose. This work was supported by the National Natural Science Foundation of China(11475047)« less

Reliability of capturing foot parameters using digital scanning and the neutral suspension casting technique

PubMed Central

2011-01-01

Background A clinical study was conducted to determine the intra and inter-rater reliability of digital scanning and the neutral suspension casting technique to measure six foot parameters. The neutral suspension casting technique is a commonly utilised method for obtaining a negative impression of the foot prior to orthotic fabrication. Digital scanning offers an alternative to the traditional plaster of Paris techniques. Methods Twenty one healthy participants volunteered to take part in the study. Six casts and six digital scans were obtained from each participant by two raters of differing clinical experience. The foot parameters chosen for investigation were cast length (mm), forefoot width (mm), rearfoot width (mm), medial arch height (mm), lateral arch height (mm) and forefoot to rearfoot alignment (degrees). Intraclass correlation coefficients (ICC) with 95% confidence intervals (CI) were calculated to determine the intra and inter-rater reliability. Measurement error was assessed through the calculation of the standard error of the measurement (SEM) and smallest real difference (SRD). Results ICC values for all foot parameters using digital scanning ranged between 0.81-0.99 for both intra and inter-rater reliability. For neutral suspension casting technique inter-rater reliability values ranged from 0.57-0.99 and intra-rater reliability values ranging from 0.36-0.99 for rater 1 and 0.49-0.99 for rater 2. Conclusions The findings of this study indicate that digital scanning is a reliable technique, irrespective of clinical experience, with reduced measurement variability in all foot parameters investigated when compared to neutral suspension casting. PMID:21375757

Improving lateral resolution and image quality of optical coherence tomography by the multi-frame superresolution technique for 3D tissue imaging

PubMed Central

Shen, Kai; Lu, Hui; Baig, Sarfaraz; Wang, Michael R.

2017-01-01

The multi-frame superresolution technique is introduced to significantly improve the lateral resolution and image quality of spectral domain optical coherence tomography (SD-OCT). Using several sets of low resolution C-scan 3D images with lateral sub-spot-spacing shifts on different sets, the multi-frame superresolution processing of these sets at each depth layer reconstructs a higher resolution and quality lateral image. Layer by layer processing yields an overall high lateral resolution and quality 3D image. In theory, the superresolution processing including deconvolution can solve the diffraction limit, lateral scan density and background noise problems together. In experiment, the improved lateral resolution by ~3 times reaching 7.81 µm and 2.19 µm using sample arm optics of 0.015 and 0.05 numerical aperture respectively as well as doubling the image quality has been confirmed by imaging a known resolution test target. Improved lateral resolution on in vitro skin C-scan images has been demonstrated. For in vivo 3D SD-OCT imaging of human skin, fingerprint and retina layer, we used the multi-modal volume registration method to effectively estimate the lateral image shifts among different C-scans due to random minor unintended live body motion. Further processing of these images generated high lateral resolution 3D images as well as high quality B-scan images of these in vivo tissues. PMID:29188089

High-speed scanning: an improved algorithm

NASA Astrophysics Data System (ADS)

Nachimuthu, A.; Hoang, Khoi

1995-10-01

In using machine vision for assessing an object's surface quality, many images are required to be processed in order to separate the good areas from the defective ones. Examples can be found in the leather hide grading process; in the inspection of garments/canvas on the production line; in the nesting of irregular shapes into a given surface... . The most common method of subtracting the total area from the sum of defective areas does not give an acceptable indication of how much of the `good' area can be used, particularly if the findings are to be used for the nesting of irregular shapes. This paper presents an image scanning technique which enables the estimation of useable areas within an inspected surface in terms of the user's definition, not the supplier's claims. That is, how much useable area the user can use, not the total good area as the supplier estimated. An important application of the developed technique is in the leather industry where the tanner (the supplier) and the footwear manufacturer (the user) are constantly locked in argument due to disputed quality standards of finished leather hide, which disrupts production schedules and wasted costs in re-grading, re- sorting... . The developed basic algorithm for area scanning of a digital image will be presented. The implementation of an improved scanning algorithm will be discussed in detail. The improved features include Boolean OR operations and many other innovative functions which aim at optimizing the scanning process in terms of computing time and the accurate estimation of useable areas.

Analytical techniques of pilot scanning behavior and their application

NASA Technical Reports Server (NTRS)

Harris, R. L., Sr.; Glover, B. J.; Spady, A. A., Jr.

1986-01-01

The state of the art of oculometric data analysis techniques and their applications in certain research areas such as pilot workload, information transfer provided by various display formats, crew role in automated systems, and pilot training are documented. These analytical techniques produce the following data: real-time viewing of the pilot's scanning behavior, average dwell times, dwell percentages, instrument transition paths, dwell histograms, and entropy rate measures. These types of data are discussed, and overviews of the experimental setup, data analysis techniques, and software are presented. A glossary of terms frequently used in pilot scanning behavior and a bibliography of reports on related research sponsored by NASA Langley Research Center are also presented.

Application of single-shot spiral scanning for volume localization.

PubMed

Ra, J B; Rim, C Y; Cho, Z H

1991-02-01

A new technique using a spiral scan single-shot RF pulse for localized volume selection has been developed and its experimental results are presented. This technique employs an additional radial-gradient coil in conjunction with the oscillating gradients for the spiral scan to localize the 3D volume. The short selection time in this technique minimizes both signal contamination from unwanted regions and signal attenuation due to T2 decay. We provide both the theoretical background of the technique and the experimental results obtained from a phantom as well as a human volunteer. The proposed method appears simple and accurate in localizing a volume which would be used as either fast imaging or localized spectroscopy.

Human prenatal diagnosis

DOE Office of Scientific and Technical Information (OSTI.GOV)

Filkins, K.; Russo, R.J.

The multiauthor text is written as a ''guide to rationalize and clarify certain aspects of diagnosis, general counseling and intervention'' for ''health professionals who provide care to pregnant women.'' The text is not aimed at the ultrasonographer but rather at the physicians who are clinically responsible for patient management. Chapters of relevance to radiologists include an overview of prenatal screening and counseling, diagnosis of neural tube defects, ultrasonographic (US) scanning of fetal disorders in the first and second trimesters of pregnancy, US scanning in the third trimester, multiple gestation and selective termination, fetal echo and Doppler studies, and fetal therapy.more » Also included are overviews of virtually all currently utilized prenatal diagnostic techniques including amniocentesis, fetal blood sampling, fetoscopy, recombinant DNA detection of hemoglobinopathies, chorionic villus sampling, embryoscopy, legal issues, and diagnosis of Mendelian disorders by DNA analysis.« less

Quantitative measurement of piezoelectric coefficient of thin film using a scanning evanescent microwave microscope.

PubMed

Zhao, Zhenli; Luo, Zhenlin; Liu, Chihui; Wu, Wenbin; Gao, Chen; Lu, Yalin

2008-06-01

This article describes a new approach to quantitatively measure the piezoelectric coefficients of thin films at the microscopic level using a scanning evanescent microwave microscope. This technique can resolve 10 pm deformation caused by the piezoelectric effect and has the advantages of high scanning speed, large scanning area, submicron spatial resolution, and a simultaneous accessibility to many other related properties. Results from the test measurements on the longitudinal piezoelectric coefficient of PZT thin film agree well with those from other techniques listed in literatures.

Fracture modes in notched angleplied composite laminates

NASA Technical Reports Server (NTRS)

Irvine, T. B.; Ginty, C. A.

1984-01-01

The Composite Durability Structural Analysis (CODSTRAN) computer code is used to determine composite fracture. Fracture modes in solid and notched, unidirectional and angleplied graphite/epoxy composites were determined by using CODSTRAN. Experimental verification included both nondestructive (ultrasonic C-Scanning) and destructive (scanning electron microscopy) techniques. The fracture modes were found to be a function of ply orientations and whether the composite is notched or unnotched. Delaminations caused by stress concentrations around notch tips were also determined. Results indicate that the composite mechanics, structural analysis, laminate analysis, and fracture criteria modules embedded in CODSTRAN are valid for determining composite fracture modes.

Integrating Elemental Analysis and Chromatography Techniques by Analyzing Metal Oxide and Organic UV Absorbers in Commercial Sunscreens

ERIC Educational Resources Information Center

Quin~ones, Rosalynn; Bayline, Jennifer Logan; Polvani, Deborah A.; Neff, David; Westfall, Tamara D.; Hijazi, Abdullah

2016-01-01

A series of undergraduate laboratory experiments that utilize reversed-phase HPLC separation, inductively coupled plasma spectroscopy (ICP), and scanning electron microscopy with energy dispersive spectroscopy (SEM-EDS) are described for the analysis of commercial sunscreens. The active ingredients of many sunscreen brands include zinc or titanium…

Trachymolgus purpureus sp. nov., an armored snout mite (Acari: Bdellidae) from the Ozark highlands: morphology, development, and key to Trachymolgus Berlese

USDA-ARS?s Scientific Manuscript database

Trachymolgus purpureus Fisher & Dowling sp. nov. is described from the Ozark highlands of North America. A diversity of imaging techniques are used to illustrate the species including field emission low-temperature scanning electron microscopy (FE-LTSEM), stereomicrography, compound light micrograph...

Poly(vinyl alcohol)/cellulose nanofibril hybrid aerogels with an aligned microtubular porous structure and their composites with polydimethylsiloxane

Treesearch

Tianliang Zhai; Qifeng Zheng; Zhiyong Cai; Lih-Sheng Turng; Hesheng Xia; Shaoqin Gong

2015-01-01

Superhydrophobic poly(vinyl alcohol) (PVA)/ cellulose nanofibril (CNF) aerogels with a unidirectionally aligned microtubular porous structure were prepared using a unidirectional freeze-drying process, followed by the thermal chemical vapor deposition of methyltrichlorosilane. The silanized aerogels were characterized using various techniques including scanning...

Effect of tree-growth rate on papermaking fibre properties

Treesearch

J. Y. Zhu; D. W. Vahey; C. T. Scott; G. C. Myers

2008-01-01

Measurements of wood density and anatomical properties of wood disks were conducted by SilviScan (CSIRO Australia) and a new imaging technique. The disks included red pine (Pinus resinosa Ait.) obtained from a never-thinned experimental forest with five different plantation densities and Douglas-fir (Pseudotsuga menziesii var. glauca (Beissn.) Franco) and lodgepole...

Nondestructive inspection of a composite missile launcher

NASA Astrophysics Data System (ADS)

Ley, O.; Chung, S.; Butera, M.; Valatka, T.; Triplett, M. H.; Godinez, V.

2012-05-01

Lighter weight alternatives are being sought to replace metallic components currently used in high performance aviation and missile systems. Benefits of lightweight, high strength carbon fiber reinforced composites in missile launchers and rocket motor cases include improved fuel economy, increased flight times, enhanced lethality and/or increased velocity. In this work, various nondestructive inspection techniques are investigated for the damage assessment of a composite missile launcher system for use in U.S. Army attack helicopters. The launcher system, which includes rails and a hardback, can be subject to impact damage from accidental tool drops, routine operation, and/or ballistic threats. The composite hardback and the launch rails both have complex geometries that can challenge the inspection process. Scanning techniques such as line scanning thermography, ultrasonic, and acousto-ultrasonics will be used and compared to determine damage detection accuracy, reliability, and efficiency. Results will also be compared with visual observations to determine if there is a correlation. The goal is to establish an inspection method that quickly and accurately assesses damage extent in order to minimize service time and return the missile system back into the field [1].

Optical coherence tomography for the diagnosis of human otitis media

NASA Astrophysics Data System (ADS)

Cho, Nam Hyun; Jung, Unsang; Jang, Jeong Hun; Jung, Woonggyu; Kim, Jeehyun; Lee, Sang Heun; Boppart, Stephen A.

2013-05-01

We report the application of Optical Coherence Tomography (OCT) to various types of human cases of otitis media (OM). Whereas conventional diagnostic modalities for OM, including standard and pneumatic otoscopy, are limited to visualizing the surface information of the tympanic membrane (TM), OCT is able to effectively reveal the depth-resolved microstructural below the TM with a very high spatial resolution. With the potential advantage of using OCT for diagnosing different types of OM, we examined in-vivo the use of 840 nm wavelength, and OCT spectral domain OCT (SDOCT) techniques, in several human cases including normal ears, and ears with adhesive and effusion types of OM. Peculiar positions were identified in two-dimensional OCT images of abnormal TMs compared to images of a normal TM. Analysis of A-scan (axial depth-scans) data from these positions could successfully identify unique patterns for different constituents within effusions. These OCT images may not only be used for constructing a database for the diagnosis and classification of OM, but they may also demonstrate the feasibility and advantages for upgrading the current otoscopy techniques.

SU-E-T-605: RapidArc Combined with DIBH Technique for Thoracic Esophageal Carcinoma: The Potential Value of Target Immobilization and Reduced Lung Density in Dose Escalation.

PubMed

Yin, Y; Liu, T; Zhai, D

2012-06-01

To compare the dosimetric benefits of Rapidarc (RA) combined with deep inspiration breath-hold (DIBH) with those of other standard techniques, including free breathing (FB) during fixed-field intensity modulated radiation therapy (IMRT) and dual arc RA, in the treatment of patients with thoracic esophageal carcinoma (EC). Ten patients with EC underwent computed tomography (CT) scans under 2 respiration conditions: free-breathing (FB) and DIBH. These scans were used to generate 3-dimensional conformal treatment plans. For breath-hold scans, the patients were brought to reproducible respiration levels using active breathing control (ABC) maneuvers. Planning target volumes (PTVs) for FB plans included a 0.5 cm margin for setup plus a 1 cm margin equal to the extent of tumor motion for respiration. PTVs for DIBH plans included a 0.5 cm margin for setup error and a 0.5 cm margin for residual uncertainty in tumor position. Using a dose level of 60 Gy to the PTV, three treatment plans were generated: IMRT-FB, RA-FB and RA-ABC, and the target and normal tissue volumes were compared, as were the dosimetry parameters. On average, the DIBH technique resulted in increased lung volumes compared with FB techniques. There was no significant differences in gross tumor volume between the two breathing states (p > 0.05); but PTV and heart volume were larger for FB than for DIBH (p < 0.05). The overall CI and HI for the RA-ABC plan was slightly inferior to those of the IMRT- FB and RA-FB plans (p < 0.05 each). With DIBH, the heart was partly out of the beam portals and the average mean heart dose was reduced. Compared with conventional FB, RA combined with DIBH significantly reduced cardiac and pulmonary doses without compromising the target coverage and may reduce treatment toxicity, enabling dose escalation in future prospective studies of patients with EC. © 2012 American Association of Physicists in Medicine.

Design and evaluation of controls for drift, video gain, and color balance in spaceborne facsimile cameras

NASA Technical Reports Server (NTRS)

Katzberg, S. J.; Kelly, W. L., IV; Rowland, C. W.; Burcher, E. E.

1973-01-01

The facsimile camera is an optical-mechanical scanning device which has become an attractive candidate as an imaging system for planetary landers and rovers. This paper presents electronic techniques which permit the acquisition and reconstruction of high quality images with this device, even under varying lighting conditions. These techniques include a control for low frequency noise and drift, an automatic gain control, a pulse-duration light modulation scheme, and a relative spectral gain control. Taken together, these techniques allow the reconstruction of radiometrically accurate and properly balanced color images from facsimile camera video data. These techniques have been incorporated into a facsimile camera and reproduction system, and experimental results are presented for each technique and for the complete system.

The Generation of Novel MR Imaging Techniques to Visualize Inflammatory/Degenerative Mechanisms and the Correlation of MR Data with 3D Microscopic Changes

DTIC Science & Technology

2013-09-01

existing MR scanning systems providing the ability to visualize structures that are impossible with current methods . Using techniques to concurrently...and unique system for analysis of affected brain regions and coupled with other imaging techniques and molecular measurements holds significant...scanning systems providing the ability to visualize structures that are impossible with current methods . Using techniques to concurrently stain

Segmentation of pulmonary nodules in three-dimensional CT images by use of a spiral-scanning technique

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wang Jiahui; Engelmann, Roger; Li Qiang

2007-12-15

Accurate segmentation of pulmonary nodules in computed tomography (CT) is an important and difficult task for computer-aided diagnosis of lung cancer. Therefore, the authors developed a novel automated method for accurate segmentation of nodules in three-dimensional (3D) CT. First, a volume of interest (VOI) was determined at the location of a nodule. To simplify nodule segmentation, the 3D VOI was transformed into a two-dimensional (2D) image by use of a key 'spiral-scanning' technique, in which a number of radial lines originating from the center of the VOI spirally scanned the VOI from the 'north pole' to the 'south pole'. Themore » voxels scanned by the radial lines provided a transformed 2D image. Because the surface of a nodule in the 3D image became a curve in the transformed 2D image, the spiral-scanning technique considerably simplified the segmentation method and enabled reliable segmentation results to be obtained. A dynamic programming technique was employed to delineate the 'optimal' outline of a nodule in the 2D image, which corresponded to the surface of the nodule in the 3D image. The optimal outline was then transformed back into 3D image space to provide the surface of the nodule. An overlap between nodule regions provided by computer and by the radiologists was employed as a performance metric for evaluating the segmentation method. The database included two Lung Imaging Database Consortium (LIDC) data sets that contained 23 and 86 CT scans, respectively, with 23 and 73 nodules that were 3 mm or larger in diameter. For the two data sets, six and four radiologists manually delineated the outlines of the nodules as reference standards in a performance evaluation for nodule segmentation. The segmentation method was trained on the first and was tested on the second LIDC data sets. The mean overlap values were 66% and 64% for the nodules in the first and second LIDC data sets, respectively, which represented a higher performance level than those of two existing segmentation methods that were also evaluated by use of the LIDC data sets. The segmentation method provided relatively reliable results for pulmonary nodule segmentation and would be useful for lung cancer quantification, detection, and diagnosis.« less

Z-scan measurements using femtosecond continuum generation

NASA Astrophysics Data System (ADS)

de Boni, Leonardo; Andrade, Acácio A.; Misoguti, Lino; Mendonça, Cléber R.; Zilio, Sérgio Carlos

2004-08-01

We present a single beam Z-scan technique using an intense, broadband, white-light continuum (WLC) beam for the direct measurement of nonlinear absorption spectra. In order to demonstrate the validity of our technique, we compared the results of tetraaniline and Sudan 3 solutions obtained with WLC and conventional single wavelength light sources. Both approaches lead to the same nonlinear spectrum, indicating that the association of the Z-scan technique and the WLC source results in an useful method for the measurement of nonlinear spectra of both absorbing (saturable absorption or reverse saturable absorption) and transparent (two-photon absorption) samples.

Spatial Angular Compounding Technique for H-Scan Ultrasound Imaging.

PubMed

Khairalseed, Mawia; Xiong, Fangyuan; Kim, Jung-Whan; Mattrey, Robert F; Parker, Kevin J; Hoyt, Kenneth

2018-01-01

H-Scan is a new ultrasound imaging technique that relies on matching a model of pulse-echo formation to the mathematics of a class of Gaussian-weighted Hermite polynomials. This technique may be beneficial in the measurement of relative scatterer sizes and in cancer therapy, particularly for early response to drug treatment. Because current H-scan techniques use focused ultrasound data acquisitions, spatial resolution degrades away from the focal region and inherently affects relative scatterer size estimation. Although the resolution of ultrasound plane wave imaging can be inferior to that of traditional focused ultrasound approaches, the former exhibits a homogeneous spatial resolution throughout the image plane. The purpose of this study was to implement H-scan using plane wave imaging and investigate the impact of spatial angular compounding on H-scan image quality. Parallel convolution filters using two different Gaussian-weighted Hermite polynomials that describe ultrasound scattering events are applied to the radiofrequency data. The H-scan processing is done on each radiofrequency image plane before averaging to get the angular compounded image. The relative strength from each convolution is color-coded to represent relative scatterer size. Given results from a series of phantom materials, H-scan imaging with spatial angular compounding more accurately reflects the true scatterer size caused by reductions in the system point spread function and improved signal-to-noise ratio. Preliminary in vivo H-scan imaging of tumor-bearing animals suggests this modality may be useful for monitoring early response to chemotherapeutic treatment. Overall, H-scan imaging using ultrasound plane waves and spatial angular compounding is a promising approach for visualizing the relative size and distribution of acoustic scattering sources. Copyright © 2018 World Federation for Ultrasound in Medicine and Biology. Published by Elsevier Inc. All rights reserved.

Fabricating Blazed Diffraction Gratings by X-Ray Lithography

NASA Technical Reports Server (NTRS)

Mouroulis, Pantazis; Hartley, Frank; Wilson, Daniel

2004-01-01

Gray-scale x-ray lithography is undergoing development as a technique for fabricating blazed diffraction gratings. As such, gray-scale x-ray lithography now complements such other grating-fabrication techniques as mechanical ruling, holography, ion etching, laser ablation, laser writing, and electron-beam lithography. Each of these techniques offers advantages and disadvantages for implementing specific grating designs; no single one of these techniques can satisfy the design requirements for all applications. Gray-scale x-ray lithography is expected to be advantageous for making gratings on steeper substrates than those that can be made by electron-beam lithography. This technique is not limited to sawtooth groove profiles and flat substrates: various groove profiles can be generated on arbitrarily shaped (including highly curved) substrates with the same ease as sawtooth profiles can be generated on flat substrates. Moreover, the gratings fabricated by this technique can be made free of ghosts (spurious diffraction components attributable to small spurious periodicities in the locations of grooves). The first step in gray-scale x-ray lithography is to conformally coat a substrate with a suitable photoresist. An x-ray mask (see Figure 1) is generated, placed between the substrate and a source of collimated x-rays, and scanned over the substrate so as to create a spatial modulation in the exposure of the photoresist. Development of the exposed photoresist results in a surface corrugation that corresponds to the spatial modulation and that defines the grating surface. The grating pattern is generated by scanning an appropriately shaped x-ray area mask along the substrate. The mask example of Figure 1 would generate a blazed grating profile when scanned in the perpendicular direction at constant speed, assuming the photoresist responds linearly to incident radiation. If the resist response is nonlinear, then the mask shape can be modified to account for the nonlinearity and produce a desired groove profile. An example of grating grooves generated by this technique is shown in Figure 2. A maximum relative efficiency of 88 percent has been demonstrated.

Higher-dimensional phase imaging

NASA Astrophysics Data System (ADS)

Huntley, Jonathan M.

2010-04-01

Traditional full-field interferometric techniques (speckle, moiré, holography etc) provide 2-D phase images, which encode the surface deformation state of the object under test. Over the past 15 years, the use of additional spatial or temporal dimensions has been investigated by a number of research groups. Early examples include the measurement of 3-D surface profiles by temporally-varying projected fringe patterns, and dynamic speckle interferometry. More recently (the past 5 years) a family of related techniques (Wavelength Scanning Interferometry, Phase Contrast Spectral Optical Coherence Tomography (OCT), and Tilt Scanning Interferometry) has emerged that provides the volume deformation state of the object. The techniques can be thought of as a marriage between the phase sensing capabilities of Phase Shifting Interferometry and the depth-sensing capabilities of OCT. Finally, in the past 12 months a technique called Hyperspectral Interferometry has been proposed in which absolute optical path distributions are obtained in a single shot through the spectral decomposition of a white light interferogram, and for which the additional dimension therefore corresponds to the illumination wavenumber. An overview of these developments, and the related issue of robust phase unwrapping of noisy 3-D wrapped phase volumes, is presented in this paper.

Confocal Imaging of porous media

NASA Astrophysics Data System (ADS)

Shah, S.; Crawshaw, D.; Boek, D.

2012-12-01

Carbonate rocks, which hold approximately 50% of the world's oil and gas reserves, have a very complicated and heterogeneous structure in comparison with sandstone reservoir rock. We present advances with different techniques to image, reconstruct, and characterize statistically the micro-geometry of carbonate pores. The main goal here is to develop a technique to obtain two dimensional and three dimensional images using Confocal Laser Scanning Microscopy. CLSM is used in epi-fluorescent imaging mode, allowing for the very high optical resolution of features well below 1μm size. Images of pore structures were captured using CLSM imaging where spaces in the carbonate samples were impregnated with a fluorescent, dyed epoxy-resin, and scanned in the x-y plane by a laser probe. We discuss the sample preparation in detail for Confocal Imaging to obtain sub-micron resolution images of heterogeneous carbonate rocks. We also discuss the technical and practical aspects of this imaging technique, including its advantages and limitation. We present several examples of this application, including studying pore geometry in carbonates, characterizing sub-resolution porosity in two dimensional images. We then describe approaches to extract statistical information about porosity using image processing and spatial correlation function. We have managed to obtain very low depth information in z -axis (~ 50μm) to develop three dimensional images of carbonate rocks with the current capabilities and limitation of CLSM technique. Hence, we have planned a novel technique to obtain higher depth information to obtain high three dimensional images with sub-micron resolution possible in the lateral and axial planes.

[A study of different polishing techniques for amalgams and glass-cermet cement by scanning electron microscope (SEM)].

PubMed

Kakaboura, A; Vougiouklakis, G; Argiri, G

1989-01-01

Finishing and polishing an amalgam restoration, is considered as an important and necessary step of the restorative procedure. Various polishing techniques have been recommended to success a smooth amalgam surface. The aim of this study was to investigate the influence of three different polishing treatments on the marginal integrity and surface smoothness of restorations made of three commercially available amalgams and a glass-cermet cement. The materials used were the amalgams, Amalcap (Vivadent), Dispersalloy (Johnson and Johnson), Duralloy (Degussa) and the glass-cermet Katac-Silver (ESPE). The occlusal surfaces of the restorations were polished by the methods: I) round bur, No4-rubber cup-zinc oxide paste in a small brush, II) round bur No 4-bur-brown, green and super green (Shofu) polishing cups and points successively and III) amalgam polishing bur of 12-blades-smooth amalgam polishing bur. Photographs from unpolished and polished surfaces of the restorations, were taken with scanning electron microscope, to evaluate the polishing techniques. An improvement of marginal integrity and surface smoothness of all amalgam restorations was observed after the specimens had been polished with the three techniques. Method II, included Shofu polishers, proved the best results in comparison to the methods I and III. Polishing of glass-cermet cement was impossible with the examined techniques.

Scanning tunnelling microscope for boron surface studies

NASA Astrophysics Data System (ADS)

Trenary, Michael

1990-10-01

The equipment purchased is to be used in an experimental study of the relationship between atomic structure and chemical reactivity for boron and carbon surfaces. This research is currently being supported by grant AFOSR-88-0111. A renewal proposal is currently pending with AFOSR to continue these studies. Carbon and boron are exceptionally stable, covalently bonded solids with highly unique crystal structures. The specific reactions to be studied are loosely related to the problems of oxidation and oxidation inhibition of carbon/carbon composites. The main experimental instrument to be used is a scanning tunneling microscope (STM) purchased under grant number AFSOR-89-0146. Other techniques to be used include Auger electron spectroscopy, X-ray photoelectron spectroscopy (XPS), ultraviolet photoelectron spectroscopy (UPS), low energy electron diffraction (LEED), temperature programmed desorption (TPD) and scanning tunneling microscopy (STM).

A Technique for Digital Impression and Bite Registration for a Single Edentulous Arch.

PubMed

Fang, Yiqin; Fang, Jing-Huan; Jeong, Seung-Mi; Choi, Byung-Ho

2018-03-09

Few studies have reported the application of digital technology for the process of impression and interocclusal recordings in edentulous patients. This article describes a digitizing system for generating digital edentulous models with a jaw relationship by taking direct digital impressions and a virtual bite registration using intraoral digital scanning. A specialized scan retractor was used to make digital impressions of edentulous jaws in patients' mouths using an intraoral scanner. Virtual bite registration was obtained with optical scanning of the buccal surfaces of both jaws at the occlusal vertical dimension. The registration was then used as a reference for aligning both jaws. Digital edentulous models that include the jaw relationship would be clinically beneficial for the fabrication of complete dentures in edentulous patients. © 2018 by the American College of Prosthodontists.

Multi-function optical characterization and inspection of MEMS components using stroboscopic coherence scanning interferometry

NASA Astrophysics Data System (ADS)

Tapilouw, Abraham Mario; Chen, Liang-Chia; Xuan-Loc, Nguyen; Chen, Jin-Liang

2014-08-01

A Micro-electro-mechanical-system (MEMS) is a widely used component in many industries, including energy, biotechnology, medical, communications, and automotive industries. However, effective inspection systems are also needed to ensure the functional reliability of MEMS. This study developed a stroboscopic coherence scanning Interferometry (SCSI) technique for measuring key characteristics typically used as criteria in MEMS inspections. Surface profiles of MEMS both static and dynamic conditions were measured by means of coherence scanning Interferometry (CSI). Resonant frequencies of vibrating MEMS were measured by deformation of interferogram fringes for out-of-plane vibration and by image correlation for in-plane vibration. The measurement bandwidth of the developed system can be tuned up to three megahertz or higher for both in-plane and out-of-plane measurement of MEMS.

SU-F-I-31: Reproducibility of An Automatic Exposure Control Technique in the Low-Dose CT Scan of Cardiac PET/CT Exams

DOE Office of Scientific and Technical Information (OSTI.GOV)

Park, M; Rosica, D; Agarwal, V

Purpose: Two separate low-dose CT scans are usually performed for attenuation correction of rest and stress N-13 ammonia PET/CT myocardial perfusion imaging (PET/CT). We utilize an automatic exposure control (AEC) technique to reduce CT radiation dose while maintaining perfusion image quality. Our goal is to assess the reproducibility of displayed CT dose index (CTDI) on same-day repeat CT scans (CT1 and CT2). Methods: Retrospectively, we reviewed CT images of PET/CT studies performed on the same day. Low-dose CT utilized AEC technique based on tube current modulation called Smart-mA. The scan parameters were 64 × 0.625mm collimation, 5mm slice thickness, 0.984more » pitch, 1-sec rotation time, 120 kVp, and noise index 50 with a range of 10–200 mA. The scan length matched with PET field of view (FOV) with the heart near the middle of axial FOV. We identified the reference slice number (RS) for an anatomical landmark (carina) and used it to estimate axial shift between two CTs. For patient size, we measured an effective diameter on the reference slice. The effect of patient positioning to CTDI was evaluated using the table height. We calculated the absolute percent difference of the CTDI (%diff) for estimation of the reproducibility. Results: The study included 168 adults with an average body-mass index of 31.72 ± 9.10 (kg/m{sup 2}) and effective diameter was 32.72 ± 4.60 cm. The average CTDI was 1.95 ± 1.40 mGy for CT1 and 1.97 ± 1.42mGy for CT2. The mean %diff was 7.8 ± 6.8%. Linear regression analysis showed a significant correlation between the table height and %diff CTDI. (r=0.82, p<0.001) Conclusion: We have shown for the first time in human subjects, using two same-day CT images, that the AEC technique in low-dose CT is reproducible within 10% and significantly depends on the patient centering.« less

Studies on image compression and image reconstruction

NASA Technical Reports Server (NTRS)

Sayood, Khalid; Nori, Sekhar; Araj, A.

1994-01-01

During this six month period our works concentrated on three, somewhat different areas. We looked at and developed a number of error concealment schemes for use in a variety of video coding environments. This work is described in an accompanying (draft) Masters thesis. In the thesis we describe application of this techniques to the MPEG video coding scheme. We felt that the unique frame ordering approach used in the MPEG scheme would be a challenge to any error concealment/error recovery technique. We continued with our work in the vector quantization area. We have also developed a new type of vector quantizer, which we call a scan predictive vector quantization. The scan predictive VQ was tested on data processed at Goddard to approximate Landsat 7 HRMSI resolution and compared favorably with existing VQ techniques. A paper describing this work is included. The third area is concerned more with reconstruction than compression. While there is a variety of efficient lossless image compression schemes, they all have a common property that they use past data to encode future data. This is done either via taking differences, context modeling, or by building dictionaries. When encoding large images, this common property becomes a common flaw. When the user wishes to decode just a portion of the image, the requirement that the past history be available forces the decoding of a significantly larger portion of the image than desired by the user. Even with intelligent partitioning of the image dataset, the number of pixels decoded may be four times the number of pixels requested. We have developed an adaptive scanning strategy which can be used with any lossless compression scheme and which lowers the additional number of pixels to be decoded to about 7 percent of the number of pixels requested! A paper describing these results is included.

Hyoid bone development: An assessment of optimal CT scanner parameters and 3D volume rendering techniques

PubMed Central

Cotter, Meghan M.; Whyms, Brian J.; Kelly, Michael P.; Doherty, Benjamin M.; Gentry, Lindell R.; Bersu, Edward T.; Vorperian, Houri K.

2015-01-01

The hyoid bone anchors and supports the vocal tract. Its complex shape is best studied in three dimensions, but it is difficult to capture on computed tomography (CT) images and three-dimensional volume renderings. The goal of this study was to determine the optimal CT scanning and rendering parameters to accurately measure the growth and developmental anatomy of the hyoid and to determine whether it is feasible and necessary to use these parameters in the measurement of hyoids from in vivo CT scans. Direct linear and volumetric measurements of skeletonized hyoid bone specimens were compared to corresponding CT images to determine the most accurate scanning parameters and three-dimensional rendering techniques. A pilot study was undertaken using in vivo scans from a retrospective CT database to determine feasibility of quantifying hyoid growth. Scanning parameters and rendering technique affected accuracy of measurements. Most linear CT measurements were within 10% of direct measurements; however, volume was overestimated when CT scans were acquired with a slice thickness greater than 1.25 mm. Slice-by-slice thresholding of hyoid images decreased volume overestimation. The pilot study revealed that the linear measurements tested correlate with age. A fine-tuned rendering approach applied to small slice thickness CT scans produces the most accurate measurements of hyoid bones. However, linear measurements can be accurately assessed from in vivo CT scans at a larger slice thickness. Such findings imply that investigation into the growth and development of the hyoid bone, and the vocal tract as a whole, can now be performed using these techniques. PMID:25810349

Hyoid Bone Development: An Assessment Of Optimal CT Scanner Parameters and Three-Dimensional Volume Rendering Techniques.

PubMed

Cotter, Meghan M; Whyms, Brian J; Kelly, Michael P; Doherty, Benjamin M; Gentry, Lindell R; Bersu, Edward T; Vorperian, Houri K

2015-08-01

The hyoid bone anchors and supports the vocal tract. Its complex shape is best studied in three dimensions, but it is difficult to capture on computed tomography (CT) images and three-dimensional volume renderings. The goal of this study was to determine the optimal CT scanning and rendering parameters to accurately measure the growth and developmental anatomy of the hyoid and to determine whether it is feasible and necessary to use these parameters in the measurement of hyoids from in vivo CT scans. Direct linear and volumetric measurements of skeletonized hyoid bone specimens were compared with corresponding CT images to determine the most accurate scanning parameters and three-dimensional rendering techniques. A pilot study was undertaken using in vivo scans from a retrospective CT database to determine feasibility of quantifying hyoid growth. Scanning parameters and rendering technique affected accuracy of measurements. Most linear CT measurements were within 10% of direct measurements; however, volume was overestimated when CT scans were acquired with a slice thickness greater than 1.25 mm. Slice-by-slice thresholding of hyoid images decreased volume overestimation. The pilot study revealed that the linear measurements tested correlate with age. A fine-tuned rendering approach applied to small slice thickness CT scans produces the most accurate measurements of hyoid bones. However, linear measurements can be accurately assessed from in vivo CT scans at a larger slice thickness. Such findings imply that investigation into the growth and development of the hyoid bone, and the vocal tract as a whole, can now be performed using these techniques. © 2015 Wiley Periodicals, Inc.

Quantitative techniques for musculoskeletal MRI at 7 Tesla.

PubMed

Bangerter, Neal K; Taylor, Meredith D; Tarbox, Grayson J; Palmer, Antony J; Park, Daniel J

2016-12-01

Whole-body 7 Tesla MRI scanners have been approved solely for research since they appeared on the market over 10 years ago, but may soon be approved for selected clinical neurological and musculoskeletal applications in both the EU and the United States. There has been considerable research work on musculoskeletal applications at 7 Tesla over the past decade, including techniques for ultra-high resolution morphological imaging, 3D T2 and T2* mapping, ultra-short TE applications, diffusion tensor imaging of cartilage, and several techniques for assessing proteoglycan content in cartilage. Most of this work has been done in the knee or other extremities, due to technical difficulties associated with scanning areas such as the hip and torso at 7 Tesla. In this manuscript, we first provide some technical context for 7 Tesla imaging, including challenges and potential advantages. We then review the major quantitative MRI techniques being applied to musculoskeletal applications on 7 Tesla whole-body systems.

Radiation dose reduction using a neck detection algorithm for single spiral brain and cervical spine CT acquisition in the trauma setting.

PubMed

Ardley, Nicholas D; Lau, Ken K; Buchan, Kevin

2013-12-01

Cervical spine injuries occur in 4-8 % of adults with head trauma. Dual acquisition technique has been traditionally used for the CT scanning of brain and cervical spine. The purpose of this study was to determine the efficacy of radiation dose reduction by using a single acquisition technique that incorporated both anatomical regions with a dedicated neck detection algorithm. Thirty trauma patients for brain and cervical spine CT were included and were scanned with the single acquisition technique. The radiation doses from the single CT acquisition technique with the neck detection algorithm, which allowed appropriate independent dose administration relevant to brain and cervical spine regions, were recorded. Comparison was made both to the doses calculated from the simulation of the traditional dual acquisitions with matching parameters, and to the doses of retrospective dual acquisition legacy technique with the same sample size. The mean simulated dose for the traditional dual acquisition technique was 3.99 mSv, comparable to the average dose of 4.2 mSv from 30 previous patients who had CT of brain and cervical spine as dual acquisitions. The mean dose from the single acquisition technique was 3.35 mSv, resulting in a 16 % overall dose reduction. The images from the single acquisition technique were of excellent diagnostic quality. The new single acquisition CT technique incorporating the neck detection algorithm for brain and cervical spine significantly reduces the overall radiation dose by eliminating the unavoidable overlapping range between 2 anatomical regions which occurs with the traditional dual acquisition technique.

Fracture Prediction by Computed Tomography and Finite Element Analysis: Current and Future Perspectives.

PubMed

Johannesdottir, Fjola; Allaire, Brett; Bouxsein, Mary L

2018-05-30

This review critiques the ability of CT-based methods to predict incident hip and vertebral fractures. CT-based techniques with concurrent calibration all show strong associations with incident hip and vertebral fracture, predicting hip and vertebral fractures as well as, and sometimes better than, dual-energy X-ray absorptiometry areal biomass density (DXA aBMD). There is growing evidence for use of routine CT scans for bone health assessment. CT-based techniques provide a robust approach for osteoporosis diagnosis and fracture prediction. It remains to be seen if further technical advances will improve fracture prediction compared to DXA aBMD. Future work should include more standardization in CT analyses, establishment of treatment intervention thresholds, and more studies to determine whether routine CT scans can be efficiently used to expand the number of individuals who undergo evaluation for fracture risk.

PRESAGE® as a solid 3-D radiation dosimeter: A review article

NASA Astrophysics Data System (ADS)

Khezerloo, Davood; Nedaie, Hassan Ali; Takavar, Abbas; Zirak, Alireza; Farhood, Bagher; Movahedinejhad, Hadi; Banaee, Nooshin; Ahmadalidokht, Isa; Knuap, Courtney

2017-12-01

Radiation oncology has been rapidly improved by the application of new equipment and techniques. With the advent of new complex and precise radiotherapy techniques such as intensity modulated radiotherapy, stereotactic radiosurgery, and volumetric modulated arc therapy, the demand for an accurate and feasible three-dimensional (3-D) dosimetry system has increased. The most important features of a 3-D dosimeter, apart from being precise, accurate and reproducible, include also its low cost, feasibility, and availability. In 2004 a new generation of solid plastic dosimeters which demonstrate a radiochromic response to ionizing radiation was introduced. PRESAGE® plastic dosimeter lacks the limitations of previous Ferric and polymer plastic 3-D dosimeters such as diffusion, sensitivity to oxygen, fabrication problems, scanning and read out challenges. In this decade, a large number of efforts have been carried out to enhance PRESAGE® structure and scanning methods. This article attempts to review and reflect on the results of these investigations.

Advances in imaging and quantification of electrical properties at the nanoscale using Scanning Microwave Impedance Microscopy (sMIM)

NASA Astrophysics Data System (ADS)

Friedman, Stuart; Yang, Yongliang; Amster, Oskar

2015-03-01

Scanning Microwave Impedance Microscopy (sMIM) is a mode for Atomic Force Microscopy (AFM) enabling imaging of unique contrast mechanisms and measurement of local permittivity and conductivity at the 10's of nm length scale. Recent results will be presented illustrating high-resolution electrical features such as sub 15 nm Moire' patterns in Graphene, carbon nanotubes of various electrical states and ferro-electrics. In addition to imaging, the technique is suited to a variety of metrology applications where specific physical properties are determined quantitatively. We will present research activities on quantitative measurements using multiple techniques to determine dielectric constant (permittivity) and conductivity (e.g. dopant concentration) for a range of materials. Examples include bulk dielectrics, low-k dielectric thin films, capacitance standards and doped semiconductors. Funded in part by DOE SBIR DE-SC0009586.

The value of dynamic infrared thermography (DIRT) in perforatorselection and planning of free DIEP flaps.

PubMed

de Weerd, Louis; Weum, Sven; Mercer, James B

2009-09-01

The aim of this paper is to evaluate dynamic infrared thermography (DIRT) as a technique to assist in preoperative perforator selection and planning of free deep inferior epigastric perforator (DIEP) flaps. Twenty-seven patients, scheduled for secondary autologous breast reconstruction with either a free DIEP flap or superficial inferior epigastric artery flap, were included in this prospective clinical study. Preoperative mapping of perforators was performed with a hand-held Doppler and DIRT. A multidetector computer tomography scan was additionally carried out in the last 8 patients. In 23 patients a DIEP flap was used. The perforator as selected from DIRT was a suitable perforator in all DIEP flaps. The location and quality of the selected perforator from DIRT corresponded well with the multidetector computer tomography scan results. Preoperative perforator selection and planning of DIEP flaps is facilitated with the use of DIRT. The technique is noninvasive and easy to use.

Scanning laser ophthalmoscopy: optimized testing strategies for psychophysics

NASA Astrophysics Data System (ADS)

Van de Velde, Frans J.

1996-12-01

Retinal function can be evaluated with the scanning laser ophthalmoscope (SLO). the main advantage is a precise localization of the psychophysical stimulus on the retina. Four alternative forced choice (4AFC) and parameter estimation by sequential testing (PEST) are classic adaptive algorithms that have been optimized for use with the SLO, and combined with strategies to correct for small eye movements. Efficient calibration procedures are essential for quantitative microperimetry. These techniques measure precisely visual acuity and retinal sensitivity at distinct locations on the retina. A combined 632 nm and IR Maxwellian view illumination provides a maximal transmittance through the ocular media and has a animal interference with xanthophyll or hemoglobin. Future modifications of the instrument include the possibility of binocular evaluation, Maxwellian view control, fundus tracking using normalized gray-scale correlation, and microphotocoagulation. The techniques are useful in low vision rehabilitation and the application of laser to the retina.

MMX-I: A data-processing software for multi-modal X-ray imaging and tomography

NASA Astrophysics Data System (ADS)

Bergamaschi, A.; Medjoubi, K.; Messaoudi, C.; Marco, S.; Somogyi, A.

2017-06-01

Scanning hard X-ray imaging allows simultaneous acquisition of multimodal information, including X-ray fluorescence, absorption, phase and dark-field contrasts, providing structural and chemical details of the samples. Combining these scanning techniques with the infrastructure developed for fast data acquisition at Synchrotron Soleil permits to perform multimodal imaging and tomography during routine user experiments at the Nanoscopium beamline. A main challenge of such imaging techniques is the online processing and analysis of the generated very large volume (several hundreds of Giga Bytes) multimodal data-sets. This is especially important for the wide user community foreseen at the user oriented Nanoscopium beamline (e.g. from the fields of Biology, Life Sciences, Geology, Geobiology), having no experience in such data-handling. MMX-I is a new multi-platform open-source freeware for the processing and reconstruction of scanning multi-technique X-ray imaging and tomographic datasets. The MMX-I project aims to offer, both expert users and beginners, the possibility of processing and analysing raw data, either on-site or off-site. Therefore we have developed a multi-platform (Mac, Windows and Linux 64bit) data processing tool, which is easy to install, comprehensive, intuitive, extendable and user-friendly. MMX-I is now routinely used by the Nanoscopium user community and has demonstrated its performance in treating big data.

A quantitative damage imaging technique based on enhanced CCRTM for composite plates using 2D scan

NASA Astrophysics Data System (ADS)

He, Jiaze; Yuan, Fuh-Gwo

2016-10-01

A two-dimensional (2D) non-contact areal scan system was developed to image and quantify impact damage in a composite plate using an enhanced zero-lag cross-correlation reverse-time migration (E-CCRTM) technique. The system comprises a single piezoelectric wafer mounted on the composite plate and a laser Doppler vibrometer (LDV) for scanning a region in the vicinity of the PZT to capture the scattered wavefield. The proposed damage imaging technique takes into account the amplitude, phase, geometric spreading, and all of the frequency content of the Lamb waves propagating in the plate; thus, a reflectivity coefficients of the delamination is calculated and potentially related to damage severity. Comparisons are made in terms of damage imaging quality between 2D areal scans and 1D line scans as well as between the proposed and existing imaging conditions. The experimental results show that the 2D E-CCRTM performs robustly when imaging and quantifying impact damage in large-scale composites using a single PZT actuator with a nearby areal scan using LDV.

An enhanced CCRTM (E-CCRTM) damage imaging technique using a 2D areal scan for composite plates

NASA Astrophysics Data System (ADS)

He, Jiaze; Yuan, Fuh-Gwo

2016-04-01

A two-dimensional (2-D) non-contact areal scan system was developed to image and quantify impact damage in a composite plate using an enhanced zero-lag cross-correlation reverse-time migration (E-CCRTM) technique. The system comprises a single piezoelectric actuator mounted on the composite plate and a laser Doppler vibrometer (LDV) for scanning a region to capture the scattered wavefield in the vicinity of the PZT. The proposed damage imaging technique takes into account the amplitude, phase, geometric spreading, and all of the frequency content of the Lamb waves propagating in the plate; thus, the reflectivity coefficients of the delamination can be calculated and potentially related to damage severity. Comparisons are made in terms of damage imaging quality between 2-D areal scans and linear scans as well as between the proposed and existing imaging conditions. The experimental results show that the 2-D E-CCRTM performs robustly when imaging and quantifying impact damage in large-scale composites using a single PZT actuator with a nearby areal scan using LDV.

Safe Active Scanning for Energy Delivery Systems Final Report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Helms, J.; Salazar, B.; Scheibel, P.

The Department of Energy’s Cybersecurity for Energy Delivery Systems Program has funded Safe(r) Active Scanning for Energy Delivery Systems, led by Lawrence Livermore National Laboratory, to investigate and analyze the impacts of active scanning in the operational environment of energy delivery systems. In collaboration with Pacific Northwest National Laboratory and Idaho National Laboratory, active scans across three testbeds including 38 devices were performed. This report gives a summary of the initial literature survey performed on the SASEDS project as well as industry partner interview summaries and main findings from Phase 1 of the project. Additionally, the report goes into themore » details of scanning techniques, methodologies for testing, testbed descriptions, and scanning results, with appendices to elaborate on the specific scans that were performed. As a result of testing, a single device out of 38 exhibited problems when actively scanned, and a reboot was required to fix it. This single failure indicates that active scanning is not likely to have a detrimental effect on the safety and resilience of energy delivery systems. We provide a path forward for future research that could enable wide adoption of active scanning and lead utilities to incorporate active scanning as part of their default network security plans to discover and rectify rogue devices, adversaries, and services that may be on the network. This increased network visibility will allow operational technology cybersecurity practitioners to improve their situational awareness of networks and their vulnerabilities.« less

Characterization of Metal Powders Used for Additive Manufacturing.

PubMed

Slotwinski, J A; Garboczi, E J; Stutzman, P E; Ferraris, C F; Watson, S S; Peltz, M A

2014-01-01

Additive manufacturing (AM) techniques can produce complex, high-value metal parts, with potential applications as critical parts, such as those found in aerospace components. The production of AM parts with consistent and predictable properties requires input materials (e.g., metal powders) with known and repeatable characteristics, which in turn requires standardized measurement methods for powder properties. First, based on our previous work, we assess the applicability of current standardized methods for powder characterization for metal AM powders. Then we present the results of systematic studies carried out on two different powder materials used for additive manufacturing: stainless steel and cobalt-chrome. The characterization of these powders is important in NIST efforts to develop appropriate measurements and standards for additive materials and to document the property of powders used in a NIST-led additive manufacturing material round robin. An extensive array of characterization techniques was applied to these two powders, in both virgin and recycled states. The physical techniques included laser diffraction particle size analysis, X-ray computed tomography for size and shape analysis, and optical and scanning electron microscopy. Techniques sensitive to structure and chemistry, including X-ray diffraction, energy dispersive analytical X-ray analysis using the X-rays generated during scanning electron microscopy, and X-Ray photoelectron spectroscopy were also employed. The results of these analyses show how virgin powder changes after being exposed to and recycled from one or more Direct Metal Laser Sintering (DMLS) additive manufacturing build cycles. In addition, these findings can give insight into the actual additive manufacturing process.

Respiratory-gated segment reconstruction for radiation treatment planning using 256-slice CT-scanner during free breathing

NASA Astrophysics Data System (ADS)

Mori, Shinichiro; Endo, Masahiro; Kohno, Ryosuke; Minohara, Shinichi; Kohno, Kazutoshi; Asakura, Hiroshi; Fujiwara, Hideaki; Murase, Kenya

2005-04-01

The conventional respiratory-gated CT scan technique includes anatomic motion induced artifacts due to the low temporal resolution. They are a significant source of error in radiotherapy treatment planning for the thorax and upper abdomen. Temporal resolution and image quality are important factors to minimize planning target volume margin due to the respiratory motion. To achieve high temporal resolution and high signal-to-noise ratio, we developed a respiratory gated segment reconstruction algorithm and adapted it to Feldkamp-Davis-Kress algorithm (FDK) with a 256-detector row CT. The 256-detector row CT could scan approximately 100 mm in the cranio-caudal direction with 0.5 mm slice thickness in one rotation. Data acquisition for the RS-FDK relies on the assistance of the respiratory sensing system by a cine scan mode (table remains stationary). We evaluated RS-FDK in phantom study with the 256-detector row CT and compared it with full scan (FS-FDK) and HS-FDK results with regard to volume accuracy and image noise, and finally adapted the RS-FDK to an animal study. The RS-FDK gave a more accurate volume than the others and it had the same signal-to-noise ratio as the FS-FDK. In the animal study, the RS-FDK visualized the clearest edges of the liver and pulmonary vessels of all the algorithms. In conclusion, the RS-FDK algorithm has a capability of high temporal resolution and high signal-to-noise ratio. Therefore it will be useful when combined with new radiotherapy techniques including image guided radiation therapy (IGRT) and 4D radiation therapy.

A digital transducer and digital microphone using an optical technique

NASA Astrophysics Data System (ADS)

Ghelmansarai, F. A.

1996-09-01

A transducer is devised to measure pressure, displacements or angles by optical means. This transducer delivers a digital output without relying on interferometry techniques or analogue-to-digital converters. This device is based on an optical scanner and an optical detector. An inter-digital photoconductive detector (IDPC) is employed that delivers a series of pulses, whose number depends on the scan length. A pre-objective scanning configuration is used that allows for the possibility of a flat image plane. The optical scanner provides scanning of IDPC and the generated scan length is proportional to the measurand.

The external morphology of adult female Egrasilus labracis as shown using hexamethyldisilazane treated, uncoated specimens for scanning electron microscopy.

PubMed

Murray, Harry M; Hill, Stephen J; Ang, Keng P

2016-07-01

The description and application of a modified Scanning Electron Microscope preparation technique using hexamethyldisilazane for small parasitic copepods was demonstrated though a high resolution depiction of individuals of Ergasilus labracis sampled from three spined stickleback (Gasterosteus aculeatus) in Bay D'Espoir, Newfoundland during summer 2015 and from archival samples retrieved from Atlantic salmon par (Salmo salar) stored at the Atlantic reference centre, St. Andrews, New Brunswick. The specimens were very well preserved showing high quality detail of important features and verifying those previously described using light microscopy by Hogans. Additionally the technique allowed excellent in situ demonstrations of mouth parts, swimming legs, and unusual and previously undescribed features of the second antenna including prominent striations and pore-like structures found to define the claw. It is thought that this technique will become a quick and efficient tool for describing important taxonomic features of small parasitic copepods like E. labracis or other similar small aquatic organisms. Microsc. Res. Tech. 79:657-663, 2016. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

SYSTEMATIC SCANNING ELECTRON MICROSCOPY TECHNIQUE FOR EVALUATING COMBINED BIOLOIGCAL/GRANULAR ACTIVATED CARBON TREATMENT PROCESSES

EPA Science Inventory

A systematic scanning election microscope analytical technique has been developed to examine granular activated carbon used a a medium for biomass attachment in liquid waste treatment. The procedure allows for the objective monitoring, comparing, and trouble shooting of combined ...

Local 2D-2D tunneling in high mobility electron systems

NASA Astrophysics Data System (ADS)

Pelliccione, Matthew; Sciambi, Adam; Bartel, John; Goldhaber-Gordon, David; Pfeiffer, Loren; West, Ken; Lilly, Michael; Bank, Seth; Gossard, Arthur

2012-02-01

Many scanning probe techniques have been utilized in recent years to measure local properties of high mobility two-dimensional (2D) electron systems in GaAs. However, most techniques lack the ability to tunnel into the buried 2D system and measure local spectroscopic information. We report scanning gate measurements on a bilayer GaAs/AlGaAs heterostructure that allows for a local modulation of tunneling between two 2D electron layers. We call this technique Virtual Scanning Tunneling Microscopy (VSTM) [1,2] as the influence of the scanning gate is analogous to an STM tip, except at a GaAs/AlGaAs interface instead of a surface. We will discuss the spectroscopic capabilities of the technique, and show preliminary results of measurements on a high mobility 2D electron system.[1] A. Sciambi, M. Pelliccione et al., Appl. Phys. Lett. 97, 132103 (2010).[2] A. Sciambi, M. Pelliccione et al., Phys. Rev. B 84, 085301 (2011).

Fusion of MRIs and CT scans for surgical treatment of cholesteatoma of the middle ear in children.

PubMed

Plouin-Gaudon, Isabelle; Bossard, Denis; Ayari-Khalfallah, Sonia; Froehlich, Patrick

2010-09-01

To evaluate the efficiency of diffusion-weighted magnetic resonance imaging (MRI) and high-resolution computed tomographic (CT) scan coregistration in predicting and adequately locating primary or recurrent cholesteatoma in children. Prospective study. Tertiary care university hospital. Ten patients aged 2 to 17 years (mean age, 8.5 years) with cholesteatoma of the middle ear, some of which were previously treated, were included for follow-up with systematic CT scanning and MRI between 2007 and 2008. Computed tomographic scanning was performed on a Siemens Somaton 128 (0.5/0.2-mm slices reformatted in 0.5/0.3-mm images). Fine cuts were obtained parallel and perpendicular to the lateral semicircular canal in each ear (100 × 100-mm field of view). Magnetic resonance imaging was undertaken on a Siemens Avanto 1.5T unit, with a protocol adapted for young children. Diffusion-weighted imaging was acquired using a single-shot turbo spin-echo mode. To allow for diagnosis and localization of the cholesteatoma, CT and diffusion-weighted MRIs were fused for each case. In 10 children, fusion technique allowed for correct diagnosis and precise localization (hypotympanum, epitympanum, mastoid recess, and attical space) as confirmed by subsequent standard surgery (positive predictive value, 100%). In 3 cases, the surgical approach was adequately determined from the fusion results. Lesion sizes on the CT-MRI fusion corresponded with perioperative findings. Recent developments in imaging techniques have made diffusion-weighted MRI more effective for detecting recurrent cholesteatoma. The major drawback of this technique, however, has been its poor anatomical and spatial discrimination. Fusion imaging using high-resolution CT and diffusion-weighted MRI appears to be a promising technique for both the diagnosis and precise localization of cholesteatomas. It provides useful information for surgical planning and, furthermore, is easy to use in pediatric cases.

Internal fixation of complex fractures of the tarsal navicular with locking plates. A report of 10 cases.

PubMed

Cronier, P; Frin, J-M; Steiger, V; Bigorre, N; Talha, A

2013-06-01

Tarsal navicular fractures are rare and treatment of comminuted fractures is especially difficult. Since 2007, the authors have had access to 3D reconstruction from CT scan images and specific locking plates, and they decided to evaluate whether these elements improved management of these severe cases. Between 2007 and 2011, 10 comminuted tarsal navicular fractures were treated in a prospective study. All of the fractures were evaluated by 3D reconstruction from CT scan images, with suppression of the posterior tarsal bones. The surgical approach was chosen according to the type of lesion. Reduction was achieved with a mini-distractor when necessary, and stabilized by AO locking plate fixation (Synthes™). Patient follow-up included a clinical and radiological evaluation (Maryland Foot score, AOFAS score). Eight patients underwent postoperative CT scan. All patients were followed up after a mean 20.5 months. Union was obtained in all patients and arthrodesis was not necessary in any of them. The mean Maryland Foot score was 92.8/100, and the AOFAS score 90.6/100. One patient with an associated comminuted calcaneal fracture had minimal sequella from a compartment syndrome of the foot. The authors did not find any series in the literature that reported evaluating tarsal navicular fractures by 3D reconstruction from CT scan images. The images obtained after suppression of the posterior tarsal bones systematically showed a lateral plantar fragment attached to the plantar calcaneonavicular ligament, which is essential for stability, and which helped determine the reduction technique. Locking plate fixation of these fractures has never been reported. Comminuted fractures of the tarsal navicular were successfully treated with specific imaging techniques in particular 3D reconstructions of CT scan images to choose the surgical approach and the reduction technique. Locking plate fixation of the navicular seems to be a satisfactory solution for the treatment of these particularly difficult fractures. Level IV. Copyright © 2013 Elsevier Masson SAS. All rights reserved.

Page layout analysis and classification for complex scanned documents

NASA Astrophysics Data System (ADS)

Erkilinc, M. Sezer; Jaber, Mustafa; Saber, Eli; Bauer, Peter; Depalov, Dejan

2011-09-01

A framework for region/zone classification in color and gray-scale scanned documents is proposed in this paper. The algorithm includes modules for extracting text, photo, and strong edge/line regions. Firstly, a text detection module which is based on wavelet analysis and Run Length Encoding (RLE) technique is employed. Local and global energy maps in high frequency bands of the wavelet domain are generated and used as initial text maps. Further analysis using RLE yields a final text map. The second module is developed to detect image/photo and pictorial regions in the input document. A block-based classifier using basis vector projections is employed to identify photo candidate regions. Then, a final photo map is obtained by applying probabilistic model based on Markov random field (MRF) based maximum a posteriori (MAP) optimization with iterated conditional mode (ICM). The final module detects lines and strong edges using Hough transform and edge-linkages analysis, respectively. The text, photo, and strong edge/line maps are combined to generate a page layout classification of the scanned target document. Experimental results and objective evaluation show that the proposed technique has a very effective performance on variety of simple and complex scanned document types obtained from MediaTeam Oulu document database. The proposed page layout classifier can be used in systems for efficient document storage, content based document retrieval, optical character recognition, mobile phone imagery, and augmented reality.

The research and development of the adaptive optics in ophthalmology

NASA Astrophysics Data System (ADS)

Wu, Chuhan; Zhang, Xiaofang; Chen, Weilin

2015-08-01

Recently the combination of adaptive optics and ophthalmology has made great progress and become highly effective. The retina disease is diagnosed by retina imaging technique based on scanning optical system, so the scanning of eye requires optical system characterized by great ability of anti-moving and optical aberration correction. The adaptive optics possesses high level of adaptability and is available for real time imaging, which meets the requirement of medical retina detection with accurate images. Now the Scanning Laser Ophthalmoscope and the Optical Coherence Tomography are widely used, which are the core techniques in the area of medical retina detection. Based on the above techniques, in China, a few adaptive optics systems used for eye medical scanning have been designed by some researchers from The Institute of Optics And Electronics of CAS(The Chinese Academy of Sciences); some foreign research institutions have adopted other methods to eliminate the interference of eye moving and optical aberration; there are many relevant patents at home and abroad. In this paper, the principles and relevant technique details of the Scanning Laser Ophthalmoscope and the Optical Coherence Tomography are described. And the recent development and progress of adaptive optics in the field of eye retina imaging are analyzed and summarized.

Developing patient-specific dose protocols for a CT scanner and exam using diagnostic reference levels.

PubMed

Strauss, Keith J

2014-10-01

The management of image quality and radiation dose during pediatric CT scanning is dependent on how well one manages the radiographic techniques as a function of the type of exam, type of CT scanner, and patient size. The CT scanner's display of expected CT dose index volume (CTDIvol) after the projection scan provides the operator with a powerful tool prior to the patient scan to identify and manage appropriate CT techniques, provided the department has established appropriate diagnostic reference levels (DRLs). This paper provides a step-by-step process that allows the development of DRLs as a function of type of exam, of actual patient size and of the individual radiation output of each CT scanner in a department. Abdomen, pelvis, thorax and head scans are addressed. Patient sizes from newborns to large adults are discussed. The method addresses every CT scanner regardless of vendor, model or vintage. We cover adjustments to techniques to manage the impact of iterative reconstruction and provide a method to handle all available voltages other than 120 kV. This level of management of CT techniques is necessary to properly monitor radiation dose and image quality during pediatric CT scans.

Computed tomography, anatomy and morphometry of the lower extremity

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hoogewoud, H.M.; Rager, G.; Burch, H.

1989-01-01

This book presents up-to-date information on CT imaging of the lower extremity. It includes an atlas correlating new, high-resolution CT scans with identical thin anatomical slices covering the lower extremity from the crista iliaca to the planta pedis. Additional figures, including CT arthrograms of the hip, knee and ankle, depict the anatomy in detail The technique and clinical relevance of CT measurements especially in orthopedic surgery are also clearly explained. Of special interest is the new method developed by the authors for assessing the coverage of the femoral head. The special morphometry software and a 3D program allowing representation inmore » space make it possible to precisely and accurately measure the coverage with normal CT scans of the hip.« less

Identification Of Cells With A Compact Microscope Imaging System With Intelligent Controls

NASA Technical Reports Server (NTRS)

McDowell, Mark (Inventor)

2006-01-01

A Microscope Imaging System (CMIS) with intelligent controls is disclosed that provides techniques for scanning, identifying, detecting and tracking mic?oscopic changes in selected characteristics or features of various surfaces including, but not limited to, cells, spheres, and manufactured products subject to difficult-to-see imperfections. The practice of the present invention provides applications that include colloidal hard spheres experiments, biological cell detection for patch clamping, cell movement and tracking, as well as defect identification in products, such as semiconductor devices, where surface damage can be significant, but difficult to detect. The CMIS system is a machine vision system, which combines intelligent image processing with remote control capabilities and provides the ability to autofocus on a microscope sample, automatically scan an image, and perform machine vision analysis on multiple samples simultaneously.

Tracking of Cells with a Compact Microscope Imaging System with Intelligent Controls

NASA Technical Reports Server (NTRS)

McDowell, Mark (Inventor)

2007-01-01

A Microscope Imaging System (CMIS) with intelligent controls is disclosed that provides techniques for scanning, identifying, detecting and tracking microscopic changes in selected characteristics or features of various surfaces including, but not limited to, cells, spheres, and manufactured products subject to difficult-to-see imperfections. The practice of the present invention provides applications that include colloidal hard spheres experiments, biological cell detection for patch clamping, cell movement and tracking, as well as defect identification in products, such as semiconductor devices, where surface damage can be significant, but difficult to detect. The CMIS system is a machine vision system, which combines intelligent image processing with remote control capabilities and provides the ability to autofocus on a microscope sample, automatically scan an image, and perform machine vision analysis on multiple samples simultaneously

Tracking of cells with a compact microscope imaging system with intelligent controls

NASA Technical Reports Server (NTRS)

McDowell, Mark (Inventor)

2007-01-01

A Microscope Imaging System (CMIS) with intelligent controls is disclosed that provides techniques for scanning, identifying, detecting and tracking microscopic changes in selected characteristics or features of various surfaces including, but not limited to, cells, spheres, and manufactured products subject to difficult-to-see imperfections. The practice of the present invention provides applications that include colloidal hard spheres experiments, biological cell detection for patch clamping, cell movement and tracking, as well as defect identification in products, such as semiconductor devices, where surface damage can be significant, but difficult to detect. The CMIS system is a machine vision system, which combines intelligent image processing with remote control capabilities and provides the ability to auto-focus on a microscope sample, automatically scan an image, and perform machine vision analysis on multiple samples simultaneously.

Operation of a Cartesian Robotic System in a Compact Microscope with Intelligent Controls

NASA Technical Reports Server (NTRS)

McDowell, Mark (Inventor)

2006-01-01

A Microscope Imaging System (CMIS) with intelligent controls is disclosed that provides techniques for scanning, identifying, detecting and tracking microscopic changes in selected characteristics or features of various surfaces including, but not limited to, cells, spheres, and manufactured products subject to difficult-to-see imperfections. The practice of the present invention provides applications that include colloidal hard spheres experiments, biological cell detection for patch clamping, cell movement and tracking, as well as defect identification in products, such as semiconductor devices, where surface damage can be significant, but difficult to detect. The CMIS system is a machine vision system, which combines intelligent image processing with remote control capabilities and provides the ability to autofocus on a microscope sample, automatically scan an image, and perform machine vision analysis on multiple samples simultaneously.

Sparse Reconstruction Techniques in MRI: Methods, Applications, and Challenges to Clinical Adoption

PubMed Central

Yang, Alice Chieh-Yu; Kretzler, Madison; Sudarski, Sonja; Gulani, Vikas; Seiberlich, Nicole

2016-01-01

The family of sparse reconstruction techniques, including the recently introduced compressed sensing framework, has been extensively explored to reduce scan times in Magnetic Resonance Imaging (MRI). While there are many different methods that fall under the general umbrella of sparse reconstructions, they all rely on the idea that a priori information about the sparsity of MR images can be employed to reconstruct full images from undersampled data. This review describes the basic ideas behind sparse reconstruction techniques, how they could be applied to improve MR imaging, and the open challenges to their general adoption in a clinical setting. The fundamental principles underlying different classes of sparse reconstructions techniques are examined, and the requirements that each make on the undersampled data outlined. Applications that could potentially benefit from the accelerations that sparse reconstructions could provide are described, and clinical studies using sparse reconstructions reviewed. Lastly, technical and clinical challenges to widespread implementation of sparse reconstruction techniques, including optimization, reconstruction times, artifact appearance, and comparison with current gold-standards, are discussed. PMID:27003227

Surface Diagnostics in Tribology Technology and Advanced Coatings Development

NASA Technical Reports Server (NTRS)

Miyoshi, Kazuhisa

1999-01-01

This paper discusses the methodologies used for surface property measurement of thin films and coatings, lubricants, and materials in the field of tribology. Surface diagnostic techniques include scanning electron microscopy, transmission electron microscopy, atomic force microscopy, stylus profilometry, x-ray diffraction, electron diffraction, Raman spectroscopy, Rutherford backscattering, elastic recoil spectroscopy, and tribology examination. Each diagnostic technique provides specific measurement results in its own unique way. In due course it should be possible to coordinate the different pieces of information provided by these diagnostic techniques into a coherent self-consistent description of the surface properties. Examples are given on the nature and character of thin diamond films.

Spectroscopic study of Pbs nano-structured layer prepared by Pld utilized as a Hall-effect magnetic sensor

NASA Astrophysics Data System (ADS)

Atwa, D. M.; Aboulfotoh, N.; El-magd, A. Abo; Badr, Y.

2013-10-01

Lead sulfide (PbS) nano-structured films have been grown on quartz substrates using PLD technique. The deposited films were characterized by several structural techniques, including scanning electron microscopy (SEM), transmission electron microscopy (TEM), and Selected-area electron diffraction patterns (SAED). The results prove the formation of cubic phase of PbS nanocrystals. Elemental analysis of the deposited films compared to the bulk target was obtained via laser induced fluorescence of the produced plasma particles and the energy dispersive X-ray "EDX" technique. The Hall coefficient measurements indicate an efficient performance of the deposited films as a magnetic sensor.

Single cell and single molecule techniques for the analysis of the epigenome

NASA Astrophysics Data System (ADS)

Wallin, Christopher Benjamin

Epigenetic regulation is a critical biological process for the health and development of a cell. Epigenetic regulation is facilitated by covalent modifications to the underlying DNA and chromatin proteins. A fundamental understanding of these epigenetic modifications and their associated interactions at the molecular scale is necessary to explain phenomena including cellular identity, stem cell plasticity, and neoplastic transformation. It is widely known that abnormal epigenetic profiles have been linked to many diseases, most notably cancer. While the field of epigenetics has progressed rapidly with conventional techniques, significant advances remain to be made with respect to combinatoric analysis of epigenetic marks and single cell epigenetics. Therefore, in this dissertation, I will discuss our development of devices and methodologies to address these pertinent issues. First, we designed a preparatory polydimethylsiloxane (PDMS) microdevice for the extraction, purification, and stretching of human chromosomal DNA and chromatin from small cell populations down to a single cell. The valveless device captures cells by size exclusion within the micropillars, entraps the DNA or chromatin in the micropillars after cell lysis, purifies away the cellular debris, and fluorescently labels the DNA and/or chromatin all within a single reaction chamber. With the device, we achieve nearly 100% extraction efficiency of the DNA. The device is also used for in-channel immunostaining of chromatin followed by downstream single molecule chromatin analysis in nanochannels (SCAN). Second, using multi-color, time-correlated single molecule measurements in nanochannels, simultaneous coincidence detection of 2 epigenetic marks is demonstrated. Coincidence detection of 3 epigenetic marks is also established using a pulsed interleaved excitation scheme. With these two promising results, genome-wide quantification of epigenetic marks was pursued. Unfortunately, quantitative SCAN never materialized. Reasons for this, including poor signal to background, are explained in detail. Third, development of mobility-SCAN, an analytical technique for measuring and analyzing single molecules based on their fluorescent signature and their electrophoretic mobility in nanochannels is described. We use the technique to differentiate biomolecules from complex mixtures and derive parameters such as diffusion coefficients and effective charges. Finally, the device is used to detect binding interactions of various complexes similar to affinity capillary electrophoresis, but on a single molecule level. Fourth, we conclude by briefly discussing SCAN-sort, a technique to sort individual chromatin molecules based on their fluorescent emissions for further downstream analysis such as DNA sequencing. We demonstrate a 2-fold enrichment of chromatin from sorting and discuss possible system modifications for better performance in the future.

Design and demonstration of multimodal optical scanning microscopy for confocal and two-photon imaging

NASA Astrophysics Data System (ADS)

Chun, Wanhee; Do, Dukho; Gweon, Dae-Gab

2013-01-01

We developed a multimodal microscopy based on an optical scanning system in order to obtain diverse optical information of the same area of a sample. Multimodal imaging researches have mostly depended on a commercial microscope platform, easy to use but restrictive to extend imaging modalities. In this work, the beam scanning optics, especially including a relay lens, was customized to transfer broadband (400-1000 nm) lights to a sample without any optical error or loss. The customized scanning optics guarantees the best performances of imaging techniques utilizing the lights within the design wavelength. Confocal reflection, confocal fluorescence, and two-photon excitation fluorescence images were obtained, through respective implemented imaging channels, to demonstrate imaging feasibility for near-UV, visible, near-IR continuous light, and pulsed light in the scanning optics. The imaging performances for spatial resolution and image contrast were verified experimentally; the results were satisfactory in comparison with theoretical results. The advantages of customization, containing low cost, outstanding combining ability and diverse applications, will contribute to vitalize multimodal imaging researches.

Development of a temperature gradient focusing method for in situ extraterrestrial biomarker analysis.

PubMed

Danger, Grégoire; Ross, David

2008-08-01

Scanning temperature gradient focusing (TGF) is a recently described technique for the simultaneous concentration and separation of charged analytes. It allows for high analyte peak capacities and low LODs in microcolumn electrophoretic separations. In this paper, we present the application of scanning TGF for chiral separations of amino acids. Using a mixture of seven carboxyfluorescein succinimidyl ester-labeled amino acids (including five chiral amino acids) which constitute the Mars7 standard, we show that scanning TGF is a very simple and efficient method for chiral separations. The modulation of TGF separation parameters (temperature window, pressure scan rate, temperature range, and chiral selector concentration) allows optimization of peak efficiencies and analyte resolutions. The use of hydroxypropyl-beta-CD at low concentration (1-5 mmol/L) as a chiral selector, with an appropriate pressure scan rate ( -0.25 Pa/s) and with a low temperature range (3-25 degrees C over 1 cm) provided high resolution between enantiomers (Rs >1.5 for each pair of enantiomers) using a short, 4 cm long capillary. With these new results, the scanning TGF method appears to be a viable method for in situ trace biomarker analysis for future missions to Mars or other solar system bodies.

Issue Scanning: Finding the Future...Maybe.

ERIC Educational Resources Information Center

Plog, Michael; Sweeney, Jim; Weiss, Barry

Issue Scanning, sometimes called Environmental Scanning, is used in many business, government, educational, and nonprofit organizations. The technique is supposed to monitor the "pulse" of the external environment. The scanning process should lessen the randomness of the information used in decision making, and it should alert managers…

Inversion of scattered radiance horizon profiles for gaseous concentrations and aerosol parameters

NASA Technical Reports Server (NTRS)

Malchow, H. L.; Whitney, C. K.

1977-01-01

Techniques have been developed and used to invert limb scan measurements for vertical profiles of atmospheric state parameters. The parameters which can be found are concentrations of Rayleigh scatters, ozone, NO2, and aerosols, and aerosol physical properties including a Junge-size distribution parameter and real and imaginary parts of the index of refraction.

Cyber Exercise Playbook

DTIC Science & Technology

2014-11-01

unclassified tools and techniques that can be shared with PNs, to include social engineering, spear phishing , fake web sites, physical access attempts, and...and instead rely on commercial services such as Yahoo or Google . Some nations have quite advanced cyber security practices, but may take vastly...unauthorized access to data/systems Inject external network scanning, email phishing , malicious website access, social engineering Sample

Effect of tree-growth rate on papermaking fiber properties

Treesearch

Junyong Zhu; David W. Vahey; C. Tim Scott; Gary C. Myers

2007-01-01

Measurements of wood density and anatomical properties of wood disks were conducted by SilviScan (CSIRO Australia) and a new imaging technique. The disks included red pine obtained from a never-thinned experimental forest with five different plantation densities and Douglas-fir and lodgepole pine (one normal growth and the other suppressed growth) both supplied by a...

Scanning measurement of Seebeck coefficient of a heated sample

DOE Office of Scientific and Technical Information (OSTI.GOV)

Snyder, G. Jeffrey; Iwanaga, Shiho

2016-04-19

A novel scanning Seebeck coefficient measurement technique is disclosed utilizing a cold scanning thermocouple probe tip on heated bulk and thin film samples. The system measures variations in the Seebeck coefficient within the samples. The apparatus may be used for two dimensional mapping of the Seebeck coefficient on the bulk and thin film samples. This technique can be utilized for detection of defective regions, as well as phase separations in the sub-mm range of various thermoelectric materials.

Comparison of a novel surface laser scanning anthropometric technique to traditional methods for facial parameter measurements.

PubMed

Joe, Paula S; Ito, Yasushi; Shih, Alan M; Oestenstad, Riedar K; Lungu, Claudiu T

2012-01-01

This study was designed to determine if three-dimensional (3D) laser scanning techniques could be used to collect accurate anthropometric measurements, compared with traditional methods. The use of an alternative 3D method would allow for quick collection of data that could be used to change the parameters used for facepiece design, improving fit and protection for a wider variety of faces. In our study, 10 facial dimensions were collected using both the traditional calipers and tape method and a Konica-Minolta Vivid9i laser scanner. Scans were combined using RapidForm XOR software to create a single complete facial geometry of the subject as a triangulated surface with an associated texture image from which to obtain measurements. A paired t-test was performed on subject means in each measurement by method. Nine subjects were used in this study: five males (one African-American and four Caucasian females) and four females displaying a range of facial dimensions. Five measurements showed significant differences (p<0.05), with most accounted for by subject movements or amended by scanning technique modifications. Laser scanning measurements showed high precision and accuracy when compared with traditional methods. Significant differences found can be very small changes in measurements and are unlikely to present a practical difference. The laser scanning technique demonstrated reliable and quick anthropometric data collection for use in future projects in redesigning respirators.

Automatic correction of echo-planar imaging (EPI) ghosting artifacts in real-time interactive cardiac MRI using sensitivity encoding.

PubMed

Kim, Yoon-Chul; Nielsen, Jon-Fredrik; Nayak, Krishna S

2008-01-01

To develop a method that automatically corrects ghosting artifacts due to echo-misalignment in interleaved gradient-echo echo-planar imaging (EPI) in arbitrary oblique or double-oblique scan planes. An automatic ghosting correction technique was developed based on an alternating EPI acquisition and the phased-array ghost elimination (PAGE) reconstruction method. The direction of k-space traversal is alternated at every temporal frame, enabling lower temporal-resolution ghost-free coil sensitivity maps to be dynamically estimated. The proposed method was compared with conventional one-dimensional (1D) phase correction in axial, oblique, and double-oblique scan planes in phantom and cardiac in vivo studies. The proposed method was also used in conjunction with two-fold acceleration. The proposed method with nonaccelerated acquisition provided excellent suppression of ghosting artifacts in all scan planes, and was substantially more effective than conventional 1D phase correction in oblique and double-oblique scan planes. The feasibility of real-time reconstruction using the proposed technique was demonstrated in a scan protocol with 3.1-mm spatial and 60-msec temporal resolution. The proposed technique with nonaccelerated acquisition provides excellent ghost suppression in arbitrary scan orientations without a calibration scan, and can be useful for real-time interactive imaging, in which scan planes are frequently changed with arbitrary oblique orientations.

Mass spectrometry for fragment screening.

PubMed

Chan, Daniel Shiu-Hin; Whitehouse, Andrew J; Coyne, Anthony G; Abell, Chris

2017-11-08

Fragment-based approaches in chemical biology and drug discovery have been widely adopted worldwide in both academia and industry. Fragment hits tend to interact weakly with their targets, necessitating the use of sensitive biophysical techniques to detect their binding. Common fragment screening techniques include differential scanning fluorimetry (DSF) and ligand-observed NMR. Validation and characterization of hits is usually performed using a combination of protein-observed NMR, isothermal titration calorimetry (ITC) and X-ray crystallography. In this context, MS is a relatively underutilized technique in fragment screening for drug discovery. MS-based techniques have the advantage of high sensitivity, low sample consumption and being label-free. This review highlights recent examples of the emerging use of MS-based techniques in fragment screening. © 2017 The Author(s). Published by Portland Press Limited on behalf of the Biochemical Society.

Testing and failure analysis to improve screening techniques for hermetically sealed metallized film capacitors for low energy applications

NASA Technical Reports Server (NTRS)

1982-01-01

Effective screening techniques are evaluated for detecting insulation resistance degradation and failure in hermetically sealed metallized film capacitors used in applications where low capacitor voltage and energy levels are common to the circuitry. A special test and monitoring system capable of rapidly scanning all test capacitors and recording faults and/or failures is examined. Tests include temperature cycling and storage as well as low, medium, and high voltage life tests. Polysulfone film capacitors are more heat stable and reliable than polycarbonate film units.

Scanning Tunneling Microscopy analysis of space-exposed polymer films

NASA Technical Reports Server (NTRS)

Kalil, Carol R.; Young, Philip R.

1993-01-01

The characterization of the surface of selected space-exposed polymer films by Scanning Tunneling Microscopy (STM) is reported. Principles of STM, an emerging new technique for materials analysis, are reviewed. The analysis of several films which received up to 5.8 years of low Earth orbital (LEO) exposure onboard the NASA Long Duration Exposure Facility (LDEF) is discussed. Specimens included FEP Teflon thermal blanket material, Kapton film, and several experimental polymer films. Ultraviolet and atomic oxygen-induced crazing and erosion are described. The intent of this paper is to demonstrate how STM is enhancing the understanding of LEO space environmental effects on polymer films.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bosarge, Christina L., E-mail: cbosarge@umail.iu.edu; Ewing, Marvene M.; DesRosiers, Colleen M.

To demonstrate the dosimetric advantages and disadvantages of standard anteroposterior-posteroanterior (S-AP/PA{sub AAA}), inverse-planned AP/PA (IP-AP/PA) and volumetry-modulated arc (VMAT) radiotherapies in the treatment of children undergoing whole-lung irradiation. Each technique was evaluated by means of target coverage and normal tissue sparing, including data regarding low doses. A historical approach with and without tissue heterogeneity corrections is also demonstrated. Computed tomography (CT) scans of 10 children scanned from the neck to the reproductive organs were used. For each scan, 6 plans were created: (1) S-AP/PA{sub AAA} using the anisotropic analytical algorithm (AAA), (2) IP-AP/PA, (3) VMAT, (4) S-AP/PA{sub NONE} without heterogeneitymore » corrections, (5) S-AP/PA{sub PB} using the Pencil-Beam algorithm and enforcing monitor units from technique 4, and (6) S-AP/PA{sub AAA[FM]} using AAA and forcing fixed monitor units. The first 3 plans compare modern methods and were evaluated based on target coverage and normal tissue sparing. Body maximum and lower body doses (50% and 30%) were also analyzed. Plans 4 to 6 provide a historic view on the progression of heterogeneity algorithms and elucidate what was actually delivered in the past. Averages of each comparison parameter were calculated for all techniques. The S-AP/PA{sub AAA} technique resulted in superior target coverage but had the highest maximum dose to every normal tissue structure. The IP-AP/PA technique provided the lowest dose to the esophagus, stomach, and lower body doses. VMAT excelled at body maximum dose and maximum doses to the heart, spine, and spleen, but resulted in the highest dose in the 30% body range. It was, however, superior to the S-AP/PA{sub AAA} approach in the 50% range. Each approach has strengths and weaknesses thus associated. Techniques may be selected on a case-by-case basis and by physician preference of target coverage vs normal tissue sparing.« less

TH-CD-202-04: Evaluation of Virtual Non-Contrast Images From a Novel Split-Filter Dual-Energy CT Technique

DOE Office of Scientific and Technical Information (OSTI.GOV)

Huang, J; Szczykutowicz, T; Bayouth, J

Purpose: To compare the ability of two dual-energy CT techniques, a novel split-filter single-source technique of superior temporal resolution against an established sequential-scan technique, to remove iodine contrast from images with minimal impact on CT number accuracy. Methods: A phantom containing 8 tissue substitute materials and vials of varying iodine concentrations (1.7–20.1 mg I /mL) was imaged using a Siemens Edge CT scanner. Dual-energy virtual non-contrast (VNC) images were generated using the novel split-filter technique, in which a 120kVp spectrum is filtered by tin and gold to create high- and low-energy spectra with < 1 second temporal separation between themore » acquisition of low- and high-energy data. Additionally, VNC images were generated with the sequential-scan technique (80 and 140kVp) for comparison. CT number accuracy was evaluated for all materials at 15, 25, and 35mGy CTDIvol. Results: The spectral separation was greater for the sequential-scan technique than the split-filter technique with dual-energy ratios of 2.18 and 1.26, respectively. Both techniques successfully removed iodine contrast, resulting in mean CT numbers within 60HU of 0HU (split-filter) and 40HU of 0HU (sequential-scan) for all iodine concentrations. Additionally, for iodine vials of varying diameter (2–20 mm) with the same concentration (9.9 mg I /mL), the system accurately detected iodine for all sizes investigated. Both dual-energy techniques resulted in reduced CT numbers for bone materials (by >400HU for the densest bone). Increasing the imaging dose did not improve the CT number accuracy for bone in VNC images. Conclusion: VNC images from the split-filter technique successfully removed iodine contrast. These results demonstrate a potential for improving dose calculation accuracy and reducing patient imaging dose, while achieving superior temporal resolution in comparison sequential scans. For both techniques, inaccuracies in CT numbers for bone materials necessitate consideration for radiation therapy treatment planning.« less

Accurate virus quantitation using a Scanning Transmission Electron Microscopy (STEM) detector in a scanning electron microscope.

PubMed

Blancett, Candace D; Fetterer, David P; Koistinen, Keith A; Morazzani, Elaine M; Monninger, Mitchell K; Piper, Ashley E; Kuehl, Kathleen A; Kearney, Brian J; Norris, Sarah L; Rossi, Cynthia A; Glass, Pamela J; Sun, Mei G

2017-10-01

A method for accurate quantitation of virus particles has long been sought, but a perfect method still eludes the scientific community. Electron Microscopy (EM) quantitation is a valuable technique because it provides direct morphology information and counts of all viral particles, whether or not they are infectious. In the past, EM negative stain quantitation methods have been cited as inaccurate, non-reproducible, and with detection limits that were too high to be useful. To improve accuracy and reproducibility, we have developed a method termed Scanning Transmission Electron Microscopy - Virus Quantitation (STEM-VQ), which simplifies sample preparation and uses a high throughput STEM detector in a Scanning Electron Microscope (SEM) coupled with commercially available software. In this paper, we demonstrate STEM-VQ with an alphavirus stock preparation to present the method's accuracy and reproducibility, including a comparison of STEM-VQ to viral plaque assay and the ViroCyt Virus Counter. Copyright © 2017 The Authors. Published by Elsevier B.V. All rights reserved.

Cartilage segmentation of 3D MRI scans of the osteoarthritic knee combining user knowledge and active contours

NASA Astrophysics Data System (ADS)

Lynch, John A.; Zaim, Souhil; Zhao, Jenny; Stork, Alexander; Peterfy, Charles G.; Genant, Harry K.

2000-06-01

A technique for segmentation of articular cartilage from 3D MRI scans of the knee has been developed. It overcomes the limitations of the conventionally used region growing techniques, which are prone to inter- and intra-observer variability, and which can require much manual intervention. We describe a hybrid segmentation method combining expert knowledge with directionally oriented Canny filters, cost functions and cubic splines. After manual initialization, the technique utilized 3 cost functions which aided automated detection of cartilage and its boundaries. Using the sign of the edge strength, and the local direction of the boundary, this technique is more reliable than conventional 'snakes,' and the user had little control over smoothness of boundaries. This means that the automatically detected boundary can conform to the true shape of the real boundary, also allowing reliable detection of subtle local lesions on the normally smooth cartilage surface. Manual corrections, with possible re-optimization were sometimes needed. When compared to the conventionally used region growing techniques, this newly described technique measured local cartilage volume with 3 times better reproducibility, and involved two thirds less human interaction. Combined with the use of 3D image registration, the new technique should also permit unbiased segmentation of followup scans by automated initialization from a baseline segmentation of an earlier scan of the same patient.

Accelerated defect visualization of microelectronic systems using binary search with fixed pitch-catch distance laser ultrasonic scanning

NASA Astrophysics Data System (ADS)

Park, Byeongjin; Sohn, Hoon

2018-04-01

The practicality of laser ultrasonic scanning is limited because scanning at a high spatial resolution demands a prohibitively long scanning time. Inspired by binary search, an accelerated defect visualization technique is developed to visualize defect with a reduced scanning time. The pitch-catch distance between the excitation point and the sensing point is also fixed during scanning to maintain a high signal-to-noise ratio of measured ultrasonic responses. The approximate defect boundary is identified by examining the interactions between ultrasonic waves and defect observed at the scanning points that are sparsely selected by a binary search algorithm. Here, a time-domain laser ultrasonic response is transformed into a spatial ultrasonic domain response using a basis pursuit approach so that the interactions between ultrasonic waves and defect can be better identified in the spatial ultrasonic domain. Then, the area inside the identified defect boundary is visualized as defect. The performance of the proposed defect visualization technique is validated through an experiment on a semiconductor chip. The proposed defect visualization technique accelerates the defect visualization process in three aspects: (1) The number of measurements that is necessary for defect visualization is dramatically reduced by a binary search algorithm; (2) The number of averaging that is necessary to achieve a high signal-to-noise ratio is reduced by maintaining the wave propagation distance short; and (3) With the proposed technique, defect can be identified with a lower spatial resolution than the spatial resolution required by full-field wave propagation imaging.

Evaluation of MR scanning, image registration, and image processing methods to visualize cortical veins for neurosurgery

NASA Astrophysics Data System (ADS)

Noordmans, Herke J.; Rutten, G. J. M.; Willems, Peter W. A.; Viergever, Max A.

2000-04-01

The visualization of brain vessels on the cortex helps the neurosurgeon in two ways: to avoid blood vessels when specifying the trepanation entry, and to overcome errors in the surgical navigation system due to brain shift. We compared 3D T1, MR, 3D T1 MR with gadolinium contrast, MR venography as scanning techniques, mutual information as registration technique, and thresholding and multi-vessel enhancement as image processing techniques. We evaluated the volume rendered results based on their quality and correspondence with photos took during surgery. It appears that with 3D T1 MR scans, gadolinium is required to show cortical veins. The visibility of small cortical veins is strongly enhanced by subtracting a 3D T1 MR baseline scan, which should be registered to the scan with gadolinium contrast, even when the scans are made during the same session. Multi-vessel enhancement helps to clarify the view on small vessels by reducing noise level, but strikingly does not reveal more. MR venography does show intracerebral veins with high detail, but is, as is, unsuited to show cortical veins due to the low contrast with CSF.

Comparison of denture tooth movement between CAD-CAM and conventional fabrication techniques.

PubMed

Goodacre, Brian J; Goodacre, Charles J; Baba, Nadim Z; Kattadiyil, Mathew T

2018-01-01

Data comparing the denture tooth movement of computer-aided design and computer-aided manufacturing (CAD-CAM) and conventional denture processing techniques are lacking. The purpose of this in vitro study was to compare the denture tooth movement of pack-and-press, fluid resin, injection, CAD-CAM-bonded, and CAD-CAM monolithic techniques for fabricating dentures to determine which process produces the most accurate and reproducible prosthesis. A total of 50 dentures were evaluated, 10 for each of the 5 groups. A master denture was fabricated and milled from prepolymerized poly(methyl methacrylate). For the conventional processing techniques (pack-and-press, fluid resin, and injection) a polyvinyl siloxane putty mold of the master denture was made in which denture teeth were placed and molten wax injected. The cameo surface of each wax-festooned denture was laser scanned, resulting in a standard tessellation language (STL) format file. The CAD-CAM dentures included 2 subgroups: CAD-CAM-bonded teeth in which the denture teeth were bonded into the milled denture base and CAD-CAM monolithic teeth in which the denture teeth were milled as part of the denture base. After all specimens had been fabricated, they were hydrated for 24 hours, and the cameo surface laser scanned. The preprocessing and postprocessing scan files of each denture were superimposed using surface-matching software. Measurements were made at 64 locations, allowing evaluation of denture tooth movement in a buccal, lingual, mesial-distal, and occlusal direction. The use of median and interquartile range values was used to assess accuracy and reproducibility. Levene and Kruskal-Wallis analyses of variance were used to evaluate differences between processing techniques (α=.05). The CAD-CAM monolithic technique was the most accurate, followed by fluid resin, CAD-CAM-bonded, pack-and-press, and injection. CAD-CAM monolithic technique was the most reproducible, followed by pack-and-press, CAD-CAM-bonded, injection, and fluid resin. Techniques involving compression during processing showed increased positive occlusal tooth movement compared with techniques not involving compression. CAD-CAM monolithic dentures produced the best combination of accuracy and reproducibility of the tested techniques. The results from this study demonstrate that varying amounts of tooth movement can be expected depending on the processing technique. However, the clinical significance of these differences is unknown. Copyright © 2017 Editorial Council for the Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.

Three-dimensional Analysis of Nanomaterials by Scanning Probe Nanotomography

NASA Astrophysics Data System (ADS)

Efimov, Anton E.; Agapova, Olga I.; Mochalov, Konstantin E.; Agapov, Igor I.

Micro and nanostructure of scaffolds made from fibroin of Bombyx mori silkworm by salt leaching technique was studied by scanning probe nanotomography. Nanopores with dimensions in range from 30 to 180 nm are observed in the scaffold volume. Three - dimensional analysis of obtained data shows that degree of scaffold nanoporosity is 0.5% and nanopores are not interconnected with each other. Usage of scanning probe nanotomography technique enables to obtain unique nanoscale information of 3D structure of biopolymer nanomaterials.

B-scan ultrasonography for the detection of space-occupying ocular masses.

PubMed

Miller, W W; Cartee, R E

1985-07-01

A noninvasive technique, B-scan ultrasonography, was used to obtain detailed cross-sectional images of ocular and orbital structure and form. When a low-frequency probe (5 MHz) was used, tissue penetration was excellent; however, axial resolution was limited. The technique was used in a study of 2 cats and 1 dog. The use of low-frequency B-scan ultrasound should aid in the diagnostic examinations of space-occupying masses in the posterior portion of the ocular bulb and the orbit.

Laser-scanning techniques for rapid ballistics identification

NASA Technical Reports Server (NTRS)

Woodburgy, R. C.; Nakich, R. B.

1974-01-01

Two different laser-scanning methods may be utilized. In each case scanned cylindrical bullet surface is displayed ""unwrapped'' on oscilloscope screen. Bullets are compared by photographing each display and superimposing negatives of two images. With some modifications bullets can be scanned and compared by superimposing images on screen of dual-beam oscilloscope.

Autoregressive linear least square single scanning electron microscope image signal-to-noise ratio estimation.

PubMed

Sim, Kok Swee; NorHisham, Syafiq

2016-11-01

A technique based on linear Least Squares Regression (LSR) model is applied to estimate signal-to-noise ratio (SNR) of scanning electron microscope (SEM) images. In order to test the accuracy of this technique on SNR estimation, a number of SEM images are initially corrupted with white noise. The autocorrelation function (ACF) of the original and the corrupted SEM images are formed to serve as the reference point to estimate the SNR value of the corrupted image. The LSR technique is then compared with the previous three existing techniques known as nearest neighbourhood, first-order interpolation, and the combination of both nearest neighborhood and first-order interpolation. The actual and the estimated SNR values of all these techniques are then calculated for comparison purpose. It is shown that the LSR technique is able to attain the highest accuracy compared to the other three existing techniques as the absolute difference between the actual and the estimated SNR value is relatively small. SCANNING 38:771-782, 2016. © 2016 Wiley Periodicals, Inc. © Wiley Periodicals, Inc.

Ultrasonic and radiographic evaluation of advanced aerospace materials: Ceramic composites

NASA Technical Reports Server (NTRS)

Generazio, Edward R.

1990-01-01

Two conventional nondestructive evaluation techniques were used to evaluate advanced ceramic composite materials. It was shown that neither ultrasonic C-scan nor radiographic imaging can individually provide sufficient data for an accurate nondestructive evaluation. Both ultrasonic C-scan and conventional radiographic imaging are required for preliminary evaluation of these complex systems. The material variations that were identified by these two techniques are porosity, delaminations, bond quality between laminae, fiber alignment, fiber registration, fiber parallelism, and processing density flaws. The degree of bonding between fiber and matrix cannot be determined by either of these methods. An alternative ultrasonic technique, angular power spectrum scanning (APSS) is recommended for quantification of this interfacial bond.

Accommodation measurements of horizontally scanning holographic display.

PubMed

Takaki, Yasuhiro; Yokouchi, Masahito

2012-02-13

Eye accommodation is considered to function properly for three-dimensional (3D) images generated by holography. We developed a horizontally scanning holographic display technique that enlarges both the screen size and viewing zone angle. A 3D image generated by this technique can be easily seen by both eyes. In this study, we measured the accommodation responses to a 3D image generated by the horizontally scanning holographic display technique that has a horizontal viewing zone angle of 14.6° and screen size of 4.3 in. We found that the accommodation responses to a 3D image displayed within 400 mm from the display screen were similar to those of a real object.

Micro/Nano-scale Strain Distribution Measurement from Sampling Moiré Fringes.

PubMed

Wang, Qinghua; Ri, Shien; Tsuda, Hiroshi

2017-05-23

This work describes the measurement procedure and principles of a sampling moiré technique for full-field micro/nano-scale deformation measurements. The developed technique can be performed in two ways: using the reconstructed multiplication moiré method or the spatial phase-shifting sampling moiré method. When the specimen grid pitch is around 2 pixels, 2-pixel sampling moiré fringes are generated to reconstruct a multiplication moiré pattern for a deformation measurement. Both the displacement and strain sensitivities are twice as high as in the traditional scanning moiré method in the same wide field of view. When the specimen grid pitch is around or greater than 3 pixels, multi-pixel sampling moiré fringes are generated, and a spatial phase-shifting technique is combined for a full-field deformation measurement. The strain measurement accuracy is significantly improved, and automatic batch measurement is easily achievable. Both methods can measure the two-dimensional (2D) strain distributions from a single-shot grid image without rotating the specimen or scanning lines, as in traditional moiré techniques. As examples, the 2D displacement and strain distributions, including the shear strains of two carbon fiber-reinforced plastic specimens, were measured in three-point bending tests. The proposed technique is expected to play an important role in the non-destructive quantitative evaluations of mechanical properties, crack occurrences, and residual stresses of a variety of materials.

Size characterization of airborne SiO2 nanoparticles with on-line and off-line measurement techniques: an interlaboratory comparison study

NASA Astrophysics Data System (ADS)

Motzkus, C.; Macé, T.; Gaie-Levrel, F.; Ducourtieux, S.; Delvallee, A.; Dirscherl, K.; Hodoroaba, V.-D.; Popov, I.; Popov, O.; Kuselman, I.; Takahata, K.; Ehara, K.; Ausset, P.; Maillé, M.; Michielsen, N.; Bondiguel, S.; Gensdarmes, F.; Morawska, L.; Johnson, G. R.; Faghihi, E. M.; Kim, C. S.; Kim, Y. H.; Chu, M. C.; Guardado, J. A.; Salas, A.; Capannelli, G.; Costa, C.; Bostrom, T.; Jämting, Å. K.; Lawn, M. A.; Adlem, L.; Vaslin-Reimann, S.

2013-10-01

Results of an interlaboratory comparison on size characterization of SiO2 airborne nanoparticles using on-line and off-line measurement techniques are discussed. This study was performed in the framework of Technical Working Area (TWA) 34—"Properties of Nanoparticle Populations" of the Versailles Project on Advanced Materials and Standards (VAMAS) in the project no. 3 "Techniques for characterizing size distribution of airborne nanoparticles". Two types of nano-aerosols, consisting of (1) one population of nanoparticles with a mean diameter between 30.3 and 39.0 nm and (2) two populations of non-agglomerated nanoparticles with mean diameters between, respectively, 36.2-46.6 nm and 80.2-89.8 nm, were generated for characterization measurements. Scanning mobility particle size spectrometers (SMPS) were used for on-line measurements of size distributions of the produced nano-aerosols. Transmission electron microscopy, scanning electron microscopy, and atomic force microscopy were used as off-line measurement techniques for nanoparticles characterization. Samples were deposited on appropriate supports such as grids, filters, and mica plates by electrostatic precipitation and a filtration technique using SMPS controlled generation upstream. The results of the main size distribution parameters (mean and mode diameters), obtained from several laboratories, were compared based on metrological approaches including metrological traceability, calibration, and evaluation of the measurement uncertainty. Internationally harmonized measurement procedures for airborne SiO2 nanoparticles characterization are proposed.

A technique for estimating 4D-CBCT using prior knowledge and limited-angle projections.

PubMed

Zhang, You; Yin, Fang-Fang; Segars, W Paul; Ren, Lei

2013-12-01

To develop a technique to estimate onboard 4D-CBCT using prior information and limited-angle projections for potential 4D target verification of lung radiotherapy. Each phase of onboard 4D-CBCT is considered as a deformation from one selected phase (prior volume) of the planning 4D-CT. The deformation field maps (DFMs) are solved using a motion modeling and free-form deformation (MM-FD) technique. In the MM-FD technique, the DFMs are estimated using a motion model which is extracted from planning 4D-CT based on principal component analysis (PCA). The motion model parameters are optimized by matching the digitally reconstructed radiographs of the deformed volumes to the limited-angle onboard projections (data fidelity constraint). Afterward, the estimated DFMs are fine-tuned using a FD model based on data fidelity constraint and deformation energy minimization. The 4D digital extended-cardiac-torso phantom was used to evaluate the MM-FD technique. A lung patient with a 30 mm diameter lesion was simulated with various anatomical and respirational changes from planning 4D-CT to onboard volume, including changes of respiration amplitude, lesion size and lesion average-position, and phase shift between lesion and body respiratory cycle. The lesions were contoured in both the estimated and "ground-truth" onboard 4D-CBCT for comparison. 3D volume percentage-difference (VPD) and center-of-mass shift (COMS) were calculated to evaluate the estimation accuracy of three techniques: MM-FD, MM-only, and FD-only. Different onboard projection acquisition scenarios and projection noise levels were simulated to investigate their effects on the estimation accuracy. For all simulated patient and projection acquisition scenarios, the mean VPD (±S.D.)∕COMS (±S.D.) between lesions in prior images and "ground-truth" onboard images were 136.11% (±42.76%)∕15.5 mm (±3.9 mm). Using orthogonal-view 15°-each scan angle, the mean VPD∕COMS between the lesion in estimated and "ground-truth" onboard images for MM-only, FD-only, and MM-FD techniques were 60.10% (±27.17%)∕4.9 mm (±3.0 mm), 96.07% (±31.48%)∕12.1 mm (±3.9 mm) and 11.45% (±9.37%)∕1.3 mm (±1.3 mm), respectively. For orthogonal-view 30°-each scan angle, the corresponding results were 59.16% (±26.66%)∕4.9 mm (±3.0 mm), 75.98% (±27.21%)∕9.9 mm (±4.0 mm), and 5.22% (±2.12%)∕0.5 mm (±0.4 mm). For single-view scan angles of 3°, 30°, and 60°, the results for MM-FD technique were 32.77% (±17.87%)∕3.2 mm (±2.2 mm), 24.57% (±18.18%)∕2.9 mm (±2.0 mm), and 10.48% (±9.50%)∕1.1 mm (±1.3 mm), respectively. For projection angular-sampling-intervals of 0.6°, 1.2°, and 2.5° with the orthogonal-view 30°-each scan angle, the MM-FD technique generated similar VPD (maximum deviation 2.91%) and COMS (maximum deviation 0.6 mm), while sparser sampling yielded larger VPD∕COMS. With equal number of projections, the estimation results using scattered 360° scan angle were slightly better than those using orthogonal-view 30°-each scan angle. The estimation accuracy of MM-FD technique declined as noise level increased. The MM-FD technique substantially improves the estimation accuracy for onboard 4D-CBCT using prior planning 4D-CT and limited-angle projections, compared to the MM-only and FD-only techniques. It can potentially be used for the inter/intrafractional 4D-localization verification.

A technique for estimating 4D-CBCT using prior knowledge and limited-angle projections

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhang, You; Yin, Fang-Fang; Ren, Lei

2013-12-15

Purpose: To develop a technique to estimate onboard 4D-CBCT using prior information and limited-angle projections for potential 4D target verification of lung radiotherapy.Methods: Each phase of onboard 4D-CBCT is considered as a deformation from one selected phase (prior volume) of the planning 4D-CT. The deformation field maps (DFMs) are solved using a motion modeling and free-form deformation (MM-FD) technique. In the MM-FD technique, the DFMs are estimated using a motion model which is extracted from planning 4D-CT based on principal component analysis (PCA). The motion model parameters are optimized by matching the digitally reconstructed radiographs of the deformed volumes tomore » the limited-angle onboard projections (data fidelity constraint). Afterward, the estimated DFMs are fine-tuned using a FD model based on data fidelity constraint and deformation energy minimization. The 4D digital extended-cardiac-torso phantom was used to evaluate the MM-FD technique. A lung patient with a 30 mm diameter lesion was simulated with various anatomical and respirational changes from planning 4D-CT to onboard volume, including changes of respiration amplitude, lesion size and lesion average-position, and phase shift between lesion and body respiratory cycle. The lesions were contoured in both the estimated and “ground-truth” onboard 4D-CBCT for comparison. 3D volume percentage-difference (VPD) and center-of-mass shift (COMS) were calculated to evaluate the estimation accuracy of three techniques: MM-FD, MM-only, and FD-only. Different onboard projection acquisition scenarios and projection noise levels were simulated to investigate their effects on the estimation accuracy.Results: For all simulated patient and projection acquisition scenarios, the mean VPD (±S.D.)/COMS (±S.D.) between lesions in prior images and “ground-truth” onboard images were 136.11% (±42.76%)/15.5 mm (±3.9 mm). Using orthogonal-view 15°-each scan angle, the mean VPD/COMS between the lesion in estimated and “ground-truth” onboard images for MM-only, FD-only, and MM-FD techniques were 60.10% (±27.17%)/4.9 mm (±3.0 mm), 96.07% (±31.48%)/12.1 mm (±3.9 mm) and 11.45% (±9.37%)/1.3 mm (±1.3 mm), respectively. For orthogonal-view 30°-each scan angle, the corresponding results were 59.16% (±26.66%)/4.9 mm (±3.0 mm), 75.98% (±27.21%)/9.9 mm (±4.0 mm), and 5.22% (±2.12%)/0.5 mm (±0.4 mm). For single-view scan angles of 3°, 30°, and 60°, the results for MM-FD technique were 32.77% (±17.87%)/3.2 mm (±2.2 mm), 24.57% (±18.18%)/2.9 mm (±2.0 mm), and 10.48% (±9.50%)/1.1 mm (±1.3 mm), respectively. For projection angular-sampling-intervals of 0.6°, 1.2°, and 2.5° with the orthogonal-view 30°-each scan angle, the MM-FD technique generated similar VPD (maximum deviation 2.91%) and COMS (maximum deviation 0.6 mm), while sparser sampling yielded larger VPD/COMS. With equal number of projections, the estimation results using scattered 360° scan angle were slightly better than those using orthogonal-view 30°-each scan angle. The estimation accuracy of MM-FD technique declined as noise level increased.Conclusions: The MM-FD technique substantially improves the estimation accuracy for onboard 4D-CBCT using prior planning 4D-CT and limited-angle projections, compared to the MM-only and FD-only techniques. It can potentially be used for the inter/intrafractional 4D-localization verification.« less

Application of gamma imaging techniques for the characterisation of position sensitive gamma detectors

NASA Astrophysics Data System (ADS)

Habermann, T.; Didierjean, F.; Duchêne, G.; Filliger, M.; Gerl, J.; Kojouharov, I.; Li, G.; Pietralla, N.; Schaffner, H.; Sigward, M.-H.

2017-11-01

A device to characterize position-sensitive germanium detectors has been implemented at GSI. The main component of this so called scanning table is a gamma camera that is capable of producing online 2D images of the scanned detector by means of a PET technique. To calibrate the gamma camera Compton imaging is employed. The 2D data can be processed further offline to obtain depth information. Of main interest is the response of the scanned detector in terms of the digitized pulse shapes from the preamplifier. This is an important input for pulse-shape analysis algorithms as they are in use for gamma tracking arrays in gamma spectroscopy. To validate the scanning table, a comparison of its results with a second scanning table implemented at the IPHC Strasbourg is envisaged. For this purpose a pixelated germanium detector has been scanned.

Aircraft and satellite measurement of ocean wave directional spectra using scanning-beam microwave radars

NASA Technical Reports Server (NTRS)

Jackson, F. C.; Walton, W. T.; Baker, P. L.

1982-01-01

A microwave radar technique for remotely measuring the vector wave number spectrum of the ocean surface is described. The technique, which employs short-pulse, noncoherent radars in a conical scan mode near vertical incidence, is shown to be suitable for both aircraft and satellite application, the technique was validated at 10 km aircraft altitude, where we have found excellent agreement between buoy and radar-inferred absolute wave height spectra.

Using structured light three-dimensional surface scanning on living individuals: Key considerations and best practice for forensic medicine.

PubMed

Shamata, Awatif; Thompson, Tim

2018-04-01

Non-contact three-dimensional (3D) surface scanning methods have been applied to forensic medicine to record injuries and to mitigate ordinary photography shortcoming. However, there are no literature concerning practical guidance for 3D surface scanning of live victims. This paper aimed to investigate key 3D scanning issues of the live body to develop a series of scanning principles for future use on injured victims. The Pico Scan 3D surface scanner was used on live test subjects. The work focused on analysing the following concerns: (1) an appropriate 3D scanning technique to scan different body areas, (2) the ideal number of scans, (3) scanning approaches to access various areas of the body and (4) elimination of environmental background noise in the acquired data. Results showed that scanning only a required surface of the body area in the stable manner was more efficient when compared to complete 360°-scanning; therefore, it used as a standard 3D scanning technique. More than three scans were sufficient when trying to obtain an optimal wireframe mode presentation of the result. Three different approaches were suggested to provide access to the various areas of the body. Undertaking scanning using a black background eliminated the background noise. The work demonstrated that the scanner will be promising to reconstruct injuries from different body areas, although the 3D scanning of the live subjects faced some challenges. Crown Copyright © 2018. Published by Elsevier Ltd. All rights reserved.

[CT pulmonary density mapping: surgical utility].

PubMed

Gavezzoli, D; Caputo, P; Manelli, A; Zuccon, W; Faccini, M; Bonandrini, L

2002-04-01

The present paper considers the technique of CT scan maps of pulmonary isodensity, examining lung density differences as a function of the type of disease and considering their significance for the purposes of refined, useful diagnosis in a surgical context. METHODS. The method is used to examine 3 groups of subjects selected on a clinical/anamnestic basis and a further group already admitted for surgery. For each patient we obtained 2 thoracic density scans during the phase of maximum inspiration and expiration. On each scan we constructed 50 isodensity maps, the equivalent of more than 2500 measurements: the preliminary standard was represented by 100 wide windows to produce total "illumination" of the pulmonary fields. The isodensity windows were then codified differently. Subsequently, the density scans were analysed with the technique of scalar decomposition. The CT scan maps of lung isodensity proved useful for certain lung diseases in which early diagnosis, topographic extent of the pathology and the refined definition of the pathological picture provide important solutions as regards the indication and planning of surgical treatment and for the evaluation of the operative risk and prognosis. We consider that the technique is rapidly performed, not complex and inexpensive and is able to supply detailed information on the lung parenchyma such as to be used not only as a routine technique but also in emergencies.

Gwyscan: a library to support non-equidistant scanning probe microscope measurements

NASA Astrophysics Data System (ADS)

Klapetek, Petr; Yacoot, Andrew; Grolich, Petr; Valtr, Miroslav; Nečas, David

2017-03-01

We present a software library and related methodology for enabling easy integration of adaptive step (non-equidistant) scanning techniques into metrological scanning probe microscopes or scanning probe microscopes where individual x, y position data are recorded during measurements. Scanning with adaptive steps can reduce the amount of data collected in SPM measurements thereby leading to faster data acquisition, a smaller amount of data collection required for a specific analytical task and less sensitivity to mechanical and thermal drift. Implementation of adaptive scanning routines into a custom built microscope is not normally an easy task: regular data are much easier to handle for previewing (e.g. levelling) and storage. We present an environment to make implementation of adaptive scanning easier for an instrument developer, specifically taking into account data acquisition approaches that are used in high accuracy microscopes as those developed by National Metrology Institutes. This includes a library with algorithms written in C and LabVIEW for handling data storage, regular mesh preview generation and planning the scan path on basis of different assumptions. A set of modules for Gwyddion open source software for handling these data and for their further analysis is presented. Using this combination of data acquisition and processing tools one can implement adaptive scanning in a relatively easy way into an instrument that was previously measuring on a regular grid. The performance of the presented approach is shown and general non-equidistant data processing steps are discussed.

The brain's silent messenger: using selective attention to decode human thought for brain-based communication.

PubMed

Naci, Lorina; Cusack, Rhodri; Jia, Vivian Z; Owen, Adrian M

2013-05-29

The interpretation of human thought from brain activity, without recourse to speech or action, is one of the most provoking and challenging frontiers of modern neuroscience. In particular, patients who are fully conscious and awake, yet, due to brain damage, are unable to show any behavioral responsivity, expose the limits of the neuromuscular system and the necessity for alternate forms of communication. Although it is well established that selective attention can significantly enhance the neural representation of attended sounds, it remains, thus far, untested as a response modality for brain-based communication. We asked whether its effect could be reliably used to decode answers to binary (yes/no) questions. Fifteen healthy volunteers answered questions (e.g., "Do you have brothers or sisters?") in the fMRI scanner, by selectively attending to the appropriate word ("yes" or "no"). Ninety percent of the answers were decoded correctly based on activity changes within the attention network. The majority of volunteers conveyed their answers with less than 3 min of scanning, suggesting that this technique is suited for communication in a reasonable amount of time. Formal comparison with the current best-established fMRI technique for binary communication revealed improved individual success rates and scanning times required to detect responses. This novel fMRI technique is intuitive, easy to use in untrained participants, and reliably robust within brief scanning times. Possible applications include communication with behaviorally nonresponsive patients.

Partial growth plate closure: apex view on bone scan

DOE Office of Scientific and Technical Information (OSTI.GOV)

Howman-Giles, R.; Trochei, M.; Yeates, K.

1985-01-01

A new technique of using /sup 99m/Tc bone scan to assess partial closure of the growth plate is described. The site and degree of osseous fusion can be obtained by using the apex view. The technique has the potential of assessing serially the growth of a plate before and after surgery.

The Exit Poll: An Environmental Scanning Technique for School Districts.

ERIC Educational Resources Information Center

House, Jess E.

1989-01-01

Exit polling of school district election returns is a form of environmental scanning that can provide information needed for strategic planning and be used to increase the effectiveness of school election campaigns. This technique is recommended for all school districts dependent on voter approval to meet revenue needs. (11 references) (MLH)

Variables Associated with Environmental Scanning among Clinicians at Substance Abuse Treatment Clinics

ERIC Educational Resources Information Center

Koch, Alison L.; Arfken, Cynthia L.; Agius, Elizabeth; Dickson, Marcus W.; Mitchelson, Jacqueline K.

2005-01-01

Introduction: Environmental scanning, as a component of absorptive capacity, has been shown to be associated with increased use of innovative treatment techniques at substance abuse treatment programmes. As the transfer of innovative, evidence-based treatment techniques from research to practice is gaining attention, we aimed to identify variables…

Characterization of Metal Powders Used for Additive Manufacturing

PubMed Central

Slotwinski, JA; Garboczi, EJ; Stutzman, PE; Ferraris, CF; Watson, SS; Peltz, MA

2014-01-01

Additive manufacturing (AM) techniques1 can produce complex, high-value metal parts, with potential applications as critical parts, such as those found in aerospace components. The production of AM parts with consistent and predictable properties requires input materials (e.g., metal powders) with known and repeatable characteristics, which in turn requires standardized measurement methods for powder properties. First, based on our previous work, we assess the applicability of current standardized methods for powder characterization for metal AM powders. Then we present the results of systematic studies carried out on two different powder materials used for additive manufacturing: stainless steel and cobalt-chrome. The characterization of these powders is important in NIST efforts to develop appropriate measurements and standards for additive materials and to document the property of powders used in a NIST-led additive manufacturing material round robin. An extensive array of characterization techniques was applied to these two powders, in both virgin and recycled states. The physical techniques included laser diffraction particle size analysis, X-ray computed tomography for size and shape analysis, and optical and scanning electron microscopy. Techniques sensitive to structure and chemistry, including X-ray diffraction, energy dispersive analytical X-ray analysis using the X-rays generated during scanning electron microscopy, and X-Ray photoelectron spectroscopy were also employed. The results of these analyses show how virgin powder changes after being exposed to and recycled from one or more Direct Metal Laser Sintering (DMLS) additive manufacturing build cycles. In addition, these findings can give insight into the actual additive manufacturing process. PMID:26601040

Cement paste surface roughness analysis using coherence scanning interferometry and confocal microscopy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Apedo, K.L., E-mail: apedo@unistra.fr; Munzer, C.; He, H.

2015-02-15

Scanning electron microscopy and scanning probe microscopy have been used for several decades to better understand the microstructure of cementitious materials. Very limited work has been performed to date to study the roughness of cementitious materials by optical microscopy such as coherence scanning interferometry (CSI) and chromatic confocal sensing (CCS). The objective of this paper is to better understand how CSI can be used as a tool to analyze surface roughness and topography of cement pastes. Observations from a series of images acquired using this technique on both polished and unpolished samples are described. The results from CSI are comparedmore » with those from a STIL confocal microscopy technique (SCM). Comparison between both optical techniques demonstrates the ability of CSI to measure both polished and unpolished cement pastes. - Highlights: • Coherence scanning interferometry (CSI) was used to analyze cement paste surfaces. • The results from the CSI were compared with those from a confocal microscopy. • 3D roughness parameters were obtained using the window resizing method. • Polished and unpolished cement pastes were studied.« less

The role of 68Ga-PSMA PET/CT scan in biochemical recurrence after primary treatment for prostate cancer: a systematic review of literature.

PubMed

Eissa, Ahmed; El Sherbiny, Ahmed; Coelho, Rafael F; Rassweiler, Jens; Davis, John W; Porpiglia, Francesco; Patel, Vipul R; Prandini, Napoleone; Micali, Salvatore; Sighinolfi, Maria C; Puliatti, Stefano; Rocco, Bernardo; Bianchi, Giampaolo

2018-04-17

Recurrence after primary treatment of prostate cancer is one of the major challenges facing urologists. Biochemical recurrence is not rare and occurs in up to one third of the patients undergoing radical prostatectomy. Management of biochemical recurrence is tailored according to the site and the burden of recurrence. Therefore, developing an imaging technique to early detect recurrent lesions represents an urgent need. Positron emission tomography (PET) of 68Ga-labelled prostate-specific membrane antigen (68Ga-PSMA) is an emerging imaging modality that seems to be a promising tool with capability to localize recurrent prostate cancer. Our aim was a systematic review of literature was done to evaluate the role of 68Ga-PSMA PET/CT scan in patients with recurrent prostate cancer after primary radical treatment. A systematic and comprehensive review of literature was performed in September 2017 analyzing the MEDLINE and Cochrane Library following the Preferred Reporting Items for Systematic Review and Meta-analysis (PRISMA) statement. The following key terms were used for the search "PSMA", "prostate-specific membrane antigen", "positron emission tomography", "PET", "recurrent", "prostate cancer", "prostate neoplasm", "prostate malignancy" and "68Ga". Risk of bias was assessed using the Quality Assessment of Diagnostic Accuracy Studies-2 tool. Thirty-seven articles met our inclusion criteria and were included in the analysis of this systematic review. Of the 37 articles selected for analysis only four studies were prospective. The overall detection rate of 68Ga PSMA PET scan ranged from 47% up to 96.6%. The main advantage of this imaging technique is its relatively high detection rates at low serum PSA levels below 0.5 ng/ml (ranging from 11.1% to 75%). Higher serum PSA level was strongly associated with increased positivity on 68Ga PSMA PET scan. 68Ga PSMA PET scan was found superior to conventional imaging techniques (CT and MRI) in this setting of patients and even it seems to outperform choline-based PET scan. This technique provided significant changes in the therapeutic management of 28.6% - 87.1% of patients. After biochemical recurrence, the primary goal is to locate the recurrent lesions' site. 68Ga-PSMA PET/CT seems to be effective in identifying recurrence localization also for very low levels of PSA (< 0.5 ng/ml) thus permitting to choose the best therapeutic strategy as early as possible. However, data available cannot be considered exhaustive and prospective randomized trials are needed.

An Investigation into the Trueness and Precision of Copy Denture Templates Produced by Rapid Prototyping and Conventional Means.

PubMed

Davda, K; Osnes, C; Dillon, S; Wu, J; Hyde, P; Keeling, A

2017-12-01

To assess the trueness and precision of copy denture templates produced using traditional methods and 3D printing. Six copies of a denture were made using: 1. Conventional technique with silicone putty in an impression tray (CT). 2. Conventional technique with no impression tray (CNT). 3. 3D scanning and printing (3D). Scan trueness and precision was investigated by scanning a denture six times and comparing five scans to the sixth. Then the scans of the six CT, CNT and 3D dentures were compared by aligning, in turn, the copies of each denture to the scanned original. Outcome measures were the mean surface-to-surface distance, standard deviation of that distance and the maximum distance. Student's unpaired t-tests with Bonferroni correction were used to analyse the results. The repeated scans of the original denture showed a scan trueness of 0.013mm (SD 0.002) and precision of 0.013mm (SD 0.002). Trueness: CT templates, 0.168mm (0.047), CNT templates 0.195mm (0.034) and 3D 0.103mm (0.021). Precision: CT templates 0.158mm (0.037), CNT 0.233mm (0.073), 3D 0.090mm (0.017). For each outcome measure the 3D templates demonstrated an improvement which was statistically significant (p⟨0.05). 3D printed copy denture templates reproduced the original with greater trueness and precision than conventional techniques. Copyright© 2017 Dennis Barber Ltd.

New prospective 4D-CT for mitigating the effects of irregular respiratory motion

NASA Astrophysics Data System (ADS)

Pan, Tinsu; Martin, Rachael M.; Luo, Dershan

2017-08-01

Artifact caused by irregular respiration is a major source of error in 4D-CT imaging. We propose a new prospective 4D-CT to mitigate this source of error without new hardware, software or off-line data-processing on the GE CT scanner. We utilize the cine CT scan in the design of the new prospective 4D-CT. The cine CT scan at each position can be stopped by the operator when an irregular respiration occurs, and resumed when the respiration becomes regular. This process can be repeated at one or multiple scan positions. After the scan, a retrospective reconstruction is initiated on the CT console to reconstruct only the images corresponding to the regular respiratory cycles. The end result is a 4D-CT free of irregular respiration. To prove feasibility, we conducted a phantom and six patient studies. The artifacts associated with the irregular respiratory cycles could be removed from both the phantom and patient studies. A new prospective 4D-CT scanning and processing technique to mitigate the impact of irregular respiration in 4D-CT has been demonstrated. This technique can save radiation dose because the repeat scans are only at the scan positions where an irregular respiration occurs. Current practice is to repeat the scans at all positions. There is no cost to apply this technique because it is applicable on the GE CT scanner without new hardware, software or off-line data-processing.

Micropillar Compression Technique Applied to Micron-Scale Mudstone Elasto-Plastic Deformation

NASA Astrophysics Data System (ADS)

Dewers, T. A.; Boyce, B.; Buchheit, T.; Heath, J. E.; Chidsey, T.; Michael, J.

2010-12-01

Mudstone mechanical testing is often limited by poor core recovery and sample size, preservation and preparation issues, which can lead to sampling bias, damage, and time-dependent effects. A micropillar compression technique, originally developed by Uchic et al. 2004, here is applied to elasto-plastic deformation of small volumes of mudstone, in the range of cubic microns. This study examines behavior of the Gothic shale, the basal unit of the Ismay zone of the Pennsylvanian Paradox Formation and potential shale gas play in southeastern Utah, USA. Precision manufacture of micropillars 5 microns in diameter and 10 microns in length are prepared using an ion-milling method. Characterization of samples is carried out using: dual focused ion - scanning electron beam imaging of nano-scaled pores and distribution of matrix clay and quartz, as well as pore-filling organics; laser scanning confocal (LSCM) 3D imaging of natural fractures; and gas permeability, among other techniques. Compression testing of micropillars under load control is performed using two different nanoindenter techniques. Deformation of 0.5 cm in diameter by 1 cm in length cores is carried out and visualized by a microscope loading stage and laser scanning confocal microscopy. Axisymmetric multistage compression testing and multi-stress path testing is carried out using 2.54 cm plugs. Discussion of results addresses size of representative elementary volumes applicable to continuum-scale mudstone deformation, anisotropy, and size-scale plasticity effects. Other issues include fabrication-induced damage, alignment, and influence of substrate. This work is funded by the US Department of Energy, Office of Basic Energy Sciences. Sandia is a multiprogram laboratory operated by Sandia Corporation, a Lockheed Martin Company, for the United States Department of Energy’s National Nuclear Security Administration under contract DE-AC04-94AL85000.

Advances in 4D Treatment Planning for Scanned Particle Beam Therapy — Report of Dedicated Workshops

PubMed Central

Bert, Christoph; Graeff, Christian; Riboldi, Marco; Nill, Simeon; Baroni, Guido; Knopf, Antje-Christin

2014-01-01

We report on recent progress in the field of mobile tumor treatment with scanned particle beams, as discussed in the latest editions of the 4D treatment planning workshop. The workshop series started in 2009, with about 20 people from 4 research institutes involved, all actively working on particle therapy delivery and development. The first workshop resulted in a summary of recommendations for the treatment of mobile targets, along with a list of requirements to apply these guidelines clinically. The increased interest in the treatment of mobile tumors led to a continuously growing number of attendees: the 2012 edition counted more than 60 participants from 20 institutions and commercial vendors. The focus of research discussions among workshop participants progressively moved from 4D treatment planning to complete 4D treatments, aiming at effective and safe treatment delivery. Current research perspectives on 4D treatments include all critical aspects of time resolved delivery, such as in-room imaging, motion detection, beam application, and quality assurance techniques. This was motivated by the start of first clinical treatments of hepato cellular tumors with a scanned particle beam, relying on gating or abdominal compression for motion mitigation. Up to date research activities emphasize significant efforts in investigating advanced motion mitigation techniques, with a specific interest in the development of dedicated tools for experimental validation. Potential improvements will be made possible in the near future through 4D optimized treatment plans that require upgrades of the currently established therapy control systems for time resolved delivery. But since also these novel optimization techniques rely on the validity of the 4DCT, research focusing on alternative 4D imaging technique, such as MRI based 4DCT generation will continue. PMID:24354749

Novel digital imaging techniques to assess the outcome in oral rehabilitation with dental implants: a narrative review.

PubMed

Benic, Goran I; Elmasry, Moustafa; Hämmerle, Christoph H F

2015-09-01

To examine the literature on novel digital imaging techniques for the assessment of outcomes in oral rehabilitation with dental implants. An electronic search of Medline and Embase databases including studies published prior to 28th December 2014 was performed and supplemented by a manual search. A synthesis of the publications was presented describing the use of computed tomography (CT), magnetic resonance imaging (MRI), ultrasonography, optical scanning, spectrophotometry or optical coherence tomography (OCT) related to the outcome measures in implant therapy. Most of the digital imaging techniques have not yet sufficiently been validated to be used for outcome measures in implant dentistry. In clinical research, cone beam CT (CBCT) is increasingly being used for 3D assessment of bone and soft tissue following augmentation procedures and implant placement. Currently, there are no effective methods for the reduction of artifacts around implants in CBCT. Optical scanning is being used for the 3D assessment of changes in the soft tissue contour. The combination of optical scan with pre-operative CBCT allows the determination of the implant position and its spatial relation to anatomical structures. Spectrophotometry is the method most commonly used to objectively assess the color match of reconstructions and peri-implant mucosa to natural dentition and gingiva. New optical imaging techniques may be considered possible approaches for monitoring peri-implant soft tissue health. MRI and ultrasonography appear promising non-ionizing radiation imaging modalities for the assessment of soft tissue and bone defect morphologies. Optical scanners and OCT may represent efficient clinical methods for accurate assessment of the misfit between the reconstructions and the implants. © 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Lipids in cheese

USDA-ARS?s Scientific Manuscript database

Lipids are present in cheese at levels above 20 percent and are analyzed by several techniques. Scanning electron microscopy and confocal laser scanning microscopy are used to examine the microstructure, gas chromatography is employed to look at fatty acid composition, and differential scanning cal...

PSD microscopy: a new technique for adaptive local scanning of microscale objects.

PubMed

Rahimi, Mehdi; Shen, Yantao

2017-01-01

A position-sensitive detector/device (PSD) is a sensor that is capable of tracking the location of a laser beam on its surface. PSDs are used in many scientific instruments and technical applications including but not limited to atomic force microscopy, human eye movement monitoring, mirrors or machine tool alignment, vibration analysis, beam position control and so on. This work intends to propose a new application using the PSD. That is a new microscopy system called scanning PSD microscopy. The working mechanism is about putting an object on the surface of the PSD and fast scanning its area with a laser beam. To achieve a high degree of accuracy and precision, a reliable framework was designed using the PSD. In this work, we first tried to improve the PSD reading and its measurement performance. This was done by minimizing the effects of noise, distortion and other disturbing parameters. After achieving a high degree of confidence, the microscopy system can be implemented based on the improved PSD measurement performance. Later to improve the scanning efficiency, we developed an adaptive local scanning system to scan the whole area of the PSD in a short matter of time. It was validated that our comprehensive and adaptive local scanning method can shorten the scanning time in order of hundreds of times in comparison with the traditional raster scanning without losing any important information about the scanned 2D objects. Methods are also introduced to scan very complicated objects with bifurcations and crossings. By incorporating all these methods, the new microscopy system is capable of scanning very complicated objects in the matter of a few seconds with a resolution that is in order of a few micrometers.

In vitro evaluation of prosthodontic impression on natural dentition: a comparison between traditional and digital techniques

PubMed Central

MALAGUTI, G.; ROSSI, R.; MARZIALI, B.; ESPOSITO, A.; BRUNO, G.; DARIOL, C.; DI FIORE, A.

2016-01-01

SUMMARY Objectives The aim of this in vitro study is to evaluate the marginal and internal fit of zirconia core crowns manufactured following different digital and traditional workflows. Methods A 6° taper shoulder prepared abutment tooth was used to produce 20 zirconia core crowns using four different scanning techniques: scanned directly with the extraoral lab scanner, scanned with intraoral scanner, dental impressions using individual dental tray and polyether, dental casts from a polyether impressions. Marginal and internal fits were evaluated with digital photography and the silicone replica method. Results Medium marginal gaps were 76,00 μm ± 28.9 for extraoral lab scanner, 80.50 μm ± 36,2 for intraoral scanner, 88.10 μm ± 34,8 for dental impression scan and 112,4 μm ± 37,2 for dental cast scan. Medium internal gaps were 23.20 μm ± 10,3 for extraoral lab scanner, 16.20 μm ± 8.3 for intraoral scanner, 27.20 μm ± 16.7 for dental impression scan and 30.20 μm ± 12.7 for dental cast scan. Conclusion Internal gap were extensively lower than 70 μm described in literature. Marginal fit was higher than ideal values for all the techniques but within the limit of clinical success. Intraoral scanners obtained the best results for internal gap. PMID:28280529

Re-designing scanning to reduce learning demands: the performance of typically developing 2-year-olds.

PubMed

McCarthy, John; Light, Janice; Drager, Kathryn; McNaughton, David; Grodzicki, Laura; Jones, Jonathan; Panek, Elizabeth; Parkin, Elizabeth

2006-12-01

Children with severe motor impairments who cannot use direct selection are typically introduced to scanning as a means of accessing assistive technology. Unfortunately, it is difficult for young children to learn to scan because the design of current scanning techniques does not always make explicit the offer of items from the selection array; furthermore, it does not provide explicit feedback after activation of the switch to select the target item. In the current study, scanning was redesigned to reduce learning demands by making both the offer of items and the feedback upon selection more explicit through the use of animation realized through HTML and speech output with appropriate intonation. Twenty typically developing 2-year-olds without disabilities were randomly assigned to use either traditional scanning or enhanced scanning to select target items from an array of three items. The 2-year-olds did not learn to use traditional scanning across three sessions. Their performance in Session 3 did not differ from that in Session 1; they did not exceed chance levels of accuracy in either session (mean accuracy of 20% for Sessions 1 and 3). In contrast, the children in the enhanced scanning condition demonstrated improvements in accuracy across the three 10-20-min sessions (mean accuracies of 22 and 48% for Sessions 1 and 3, respectively). There were no reliable differences between the children's performances with the two scanning techniques for Session 1; however, by Session 3, the children were more than twice as accurate using the enhanced scanning technique compared to the traditional design. Results suggest that by redesigning scanning, we may be able to reduce some of the learning demands and thereby reduce some of the instructional time required for children to attain mastery. Clinical implications, limitations, and directions for future research and development are discussed.

Porous silicon - rare earth doped xerogel and glass composites

NASA Astrophysics Data System (ADS)

Balakrishnan, S.; Gun'ko, Yurii K.; Perova, T. S.; Rafferty, A.; Astrova, E. V.; Moore, R. A.

2005-06-01

The development of components for photonics applications is growing exponentially. The sol-gel method is now recognised as a convenient and flexible way to deposit oxide or glass films on a variety of hosts, including porous silicon. In the present work we incorporated erbium and europium doped xerogel into porous silicon and developed new porous silicon - rare earth doped glass composites. Various characteris-ation techniques including FTIR, Raman Spectroscopy, Thermal Gravimetric Analysis and Scanning Electron Microscopy were employed in this work.

Design of a practical model-observer-based image quality assessment method for x-ray computed tomography imaging systems

PubMed Central

Tseng, Hsin-Wu; Fan, Jiahua; Kupinski, Matthew A.

2016-01-01

Abstract. The use of a channelization mechanism on model observers not only makes mimicking human visual behavior possible, but also reduces the amount of image data needed to estimate the model observer parameters. The channelized Hotelling observer (CHO) and channelized scanning linear observer (CSLO) have recently been used to assess CT image quality for detection tasks and combined detection/estimation tasks, respectively. Although the use of channels substantially reduces the amount of data required to compute image quality, the number of scans required for CT imaging is still not practical for routine use. It is our desire to further reduce the number of scans required to make CHO or CSLO an image quality tool for routine and frequent system validations and evaluations. This work explores different data-reduction schemes and designs an approach that requires only a few CT scans. Three different kinds of approaches are included in this study: a conventional CHO/CSLO technique with a large sample size, a conventional CHO/CSLO technique with fewer samples, and an approach that we will show requires fewer samples to mimic conventional performance with a large sample size. The mean value and standard deviation of areas under ROC/EROC curve were estimated using the well-validated shuffle approach. The results indicate that an 80% data reduction can be achieved without loss of accuracy. This substantial data reduction is a step toward a practical tool for routine-task-based QA/QC CT system assessment. PMID:27493982

Examination of forensic entomology evidence using computed tomography scanning: case studies and refinement of techniques for estimating maggot mass volumes in bodies.

PubMed

Johnson, Aidan; Archer, Melanie; Leigh-Shaw, Lyndie; Pais, Mike; O'Donnell, Chris; Wallman, James

2012-09-01

A new technique has recently been developed for estimating the volume of maggot masses on deceased persons using post-mortem CT scans. This allows volume to be measured non-invasively and factored into maggot mass temperature calculations for both casework and research. Examination of admission scans also allows exploration of entomological evidence in anatomical areas not usually exposed by autopsy (e.g. nasal cavities and facial sinuses), and before autopsy disrupts the maggot distribution on a body. This paper expands on work already completed by providing the x-ray attenuation coefficient by way of Hounsfield unit (HU) values for various maggot species, maggot masses and human tissue adjacent to masses. Specifically, this study looked at the HU values for four forensically important blowfly larvae: Lucilia cuprina, L. sericata, Calliphora stygia and C. vicina. The Calliphora species had significantly lower HU values than the Lucilia species. This might be explained by histological analysis, which revealed a non-significant trend, suggesting that Calliphora maggots have a higher fat content than the Lucilia maggots. It is apparent that the variation in the x-ray attenuation coefficient usually precludes its use as a tool for delineating the maggot mass from human tissue and that morphology is the dominant method for delineating a mass. This paper also includes three case studies, which reveal different applications for interpreting entomological evidence using post-mortem CT scans.

A planar near-field scanning technique for bistatic radar cross section measurements

NASA Technical Reports Server (NTRS)

Tuhela-Reuning, S.; Walton, E. K.

1990-01-01

A progress report on the development of a bistatic radar cross section (RCS) measurement range is presented. A technique using one parabolic reflector and a planar scanning probe antenna is analyzed. The field pattern in the test zone is computed using a spatial array of signal sources. It achieved an illumination pattern with 1 dB amplitude and 15 degree phase ripple over the target zone. The required scan plane size is found to be proportional to the size of the desired test target. Scan plane probe sample spacing can be increased beyond the Nyquist lambda/2 limit permitting constant probe sample spacing over a range of frequencies.

Ratioed scatter diagrams - An erotetic method for phase identification on complex surfaces using scanning Auger microscopy

NASA Technical Reports Server (NTRS)

Browning, R.

1984-01-01

By ratioing multiple Auger intensities and plotting a two-dimensional occupational scatter diagram while digitally scanning across an area, the number and elemental association of surface phases can be determined. This can prove a useful tool in scanning Auger microscopic analysis of complex materials. The technique is illustrated by results from an anomalous region on the reaction zone of a SiC/Ti-6Al-4V metal matrix composite material. The anomalous region is shown to be a single phase associated with sulphur and phosphorus impurities. Imaging of a selected phase from the ratioed scatter diagram is possible and may be a useful technique for presenting multiple scanning Auger images.

Contribution of postmortem multidetector CT scanning to identification of the deceased in a mass disaster: Experience gained from the 2009 Victorian bushfires.

PubMed

O'Donnell, C; Iino, M; Mansharan, K; Leditscke, J; Woodford, N

2011-02-25

CT scanning of the deceased is an established technique performed on all individuals admitted to VIFM over the last 5 years. It is used primarily to assist pathologists in determining cause and manner of death but is also invaluable for identification of unknown deceased individuals where traditional methods are not possible. Based on this experience, CT scanning was incorporated into phase 2 of the Institute's DVI process for the 2009 Victorian bushfires. All deceased individuals and fragmented remains admitted to the mortuary were CT scanned in their body bags using established protocols. Images were reviewed by 2 teams of 2 radiologists experienced in forensic imaging and the findings transcribed onto a data sheet constructed specifically for the DVI exercise. The contents of 255 body bags were examined in the 28 days following the fires. 164 missing persons were included in the DVI process with 163 deceased individuals eventually identified. CT contributed to this identification in 161 persons. In 2 cases, radiologists were unable to recognize commingled remains. CT was utilized in the initial triage of each bag's contents. If radiological evaluation determined that bodies were incomplete then this information was provided to search teams who revisited the scenes of death. CT was helpful in differentiation of human from non-human remains in 8 bags, recognition of human/animal commingling in 10 bags and human commingling in 6 bags. In 61% of cases gender was able to be determined on CT using a novel technique of genitalia detection and in all but 2 cases this was correct. Age range was able to be determined on CT in 94% with an accuracy of 76%. Specific identification features detected on CT included the presence of disease (14 disease entities in 13 cases), medical devices (26 devices in 19 cases) and 274 everyday metallic items associated with the remains of 135 individuals. CT scanning provided useful information prior to autopsy by flagging likely findings including the presence of non-human remains, at the time of autopsy by assisting in the localization of identifying features in heavily disfigured bodies, and after autopsy by retrospective review of images for clarification of issues that arose at the time of pathologist case review. In view of the success of CT scanning in this mass disaster, DVI administrators should explore the incorporation of CT services into their disaster plans. Copyright © 2010 Elsevier Ireland Ltd. All rights reserved.

Quantitative techniques for musculoskeletal MRI at 7 Tesla

PubMed Central

Taylor, Meredith D.; Tarbox, Grayson J.; Palmer, Antony J.; Park, Daniel J.

2016-01-01

Whole-body 7 Tesla MRI scanners have been approved solely for research since they appeared on the market over 10 years ago, but may soon be approved for selected clinical neurological and musculoskeletal applications in both the EU and the United States. There has been considerable research work on musculoskeletal applications at 7 Tesla over the past decade, including techniques for ultra-high resolution morphological imaging, 3D T2 and T2* mapping, ultra-short TE applications, diffusion tensor imaging of cartilage, and several techniques for assessing proteoglycan content in cartilage. Most of this work has been done in the knee or other extremities, due to technical difficulties associated with scanning areas such as the hip and torso at 7 Tesla. In this manuscript, we first provide some technical context for 7 Tesla imaging, including challenges and potential advantages. We then review the major quantitative MRI techniques being applied to musculoskeletal applications on 7 Tesla whole-body systems. PMID:28090448

Characterization of ultrafast devices using novel optical techniques

NASA Astrophysics Data System (ADS)

Ali, Md Ershad

Optical techniques have been extensively used to examine the high frequency performance of a number of devices including High Electron Mobility Transistors (HEMTs), Heterojunction Bipolar Phototransistors (HPTs) and Low Temperature GaAs (LT-GaAs) Photoconductive Switches. To characterize devices, frequency and time domain techniques, namely optical heterodyning and electro-optic sampling, having measurement bandwidths in excess of 200 GHz, were employed. Optical mixing in three-terminal devices has been extended for the first time to submillimeter wave frequencies. Using a new generation of 50-nm gate pseudomorphic InP-based HEMTs, optically mixed signals were detected to 552 GHz with a signal-to-noise ratio of approximately 5 dB. To the best of our knowledge, this is the highest frequency optical mixing obtained in three- terminal devices to date. A novel harmonic three-wave detection scheme was used for the detection of the optically generated signals. The technique involved downconversion of the signal in the device by the second harmonic of a gate-injected millimeter wave local oscillator. Measurements were also conducted up to 212 GHz using direct optical mixing and up to 382 GHz using a fundamental three-wave detection scheme. New interesting features in the bias dependence of the optically mixed signals have been reported. An exciting novel development from this work is the successful integration of near-field optics with optical heterodyning. The technique, called near-field optical heterodyning (NFOH), allows for extremely localized injection of high-frequency stimulus to any arbitrary point of an ultrafast device or circuit. Scanning the point of injection across the sample provides details of the high frequency operation of the device with high spatial resolution. For the implementation of the technique, fiber-optic probes with 100 nm apertures were fabricated. A feedback controlled positioning system was built for accurate placement and scanning of the fiber probe with nanometric precision. The applicability of the NFOH technique was first confirmed by measurements on heterojunction phototransistors at 100 GHz. Later NFOH scans were performed at 63 GHz on two other important devices, HEMTs and LT-GaAs Photoconductive Switches. Spatially resolved response characteristics of these devices revealed interesting details of their operation.

A CT and MRI scan to MCNP input conversion program.

PubMed

Van Riper, Kenneth A

2005-01-01

We describe a new program to read a sequence of tomographic scans and prepare the geometry and material sections of an MCNP input file. Image processing techniques include contrast controls and mapping of grey scales to colour. The user interface provides several tools with which the user can associate a range of image intensities to an MCNP material. Materials are loaded from a library. A separate material assignment can be made to a pixel intensity or range of intensities when that intensity dominates the image boundaries; this material is assigned to all pixels with that intensity contiguous with the boundary. Material fractions are computed in a user-specified voxel grid overlaying the scans. New materials are defined by mixing the library materials using the fractions. The geometry can be written as an MCNP lattice or as individual cells. A combination algorithm can be used to join neighbouring cells with the same material.

The long range voice coil atomic force microscope

DOE Office of Scientific and Technical Information (OSTI.GOV)

Barnard, H.; Randall, C.; Bridges, D.

2012-02-15

Most current atomic force microscopes (AFMs) use piezoelectric ceramics for scan actuation. Piezoelectric ceramics provide precision motion with fast response to applied voltage potential. A drawback to piezoelectric ceramics is their inherently limited ranges. For many samples this is a nonissue, as imaging the nanoscale details is the goal. However, a key advantage of AFM over other microscopy techniques is its ability to image biological samples in aqueous buffer. Many biological specimens have topography for which the range of piezoactuated stages is limiting, a notable example of which is bone. In this article, we present the use of voice coilsmore » in scan actuation for an actuation range in the Z-axis an order of magnitude larger than any AFM commercially available today. The increased scan size will allow for imaging an important new variety of samples, including bone fractures.« less

EBIC spectroscopy - A new approach to microscale characterization of deep levels in semi-insulating GaAs

NASA Technical Reports Server (NTRS)

Li, C.-J.; Sun, Q.; Lagowski, J.; Gatos, H. C.

1985-01-01

The microscale characterization of electronic defects in (SI) GaAs has been a challenging issue in connection with materials problems encountered in GaAs IC technology. The main obstacle which limits the applicability of high resolution electron beam methods such as Electron Beam-Induced Current (EBIC) and cathodoluminescence (CL) is the low concentration of free carriers in semiinsulating (SI) GaAs. The present paper provides a new photo-EBIC characterization approach which combines the spectroscopic advantages of optical methods with the high spatial resolution and scanning capability of EBIC. A scanning electron microscope modified for electronic characterization studies is shown schematically. The instrument can operate in the standard SEM mode, in the EBIC modes (including photo-EBIC and thermally stimulated EBIC /TS-EBIC/), and in the cathodo-luminescence (CL) and scanning modes. Attention is given to the use of CL, Photo-EBIC, and TS-EBIC techniques.

MEMS scanning micromirror for optical coherence tomography.

PubMed

Strathman, Matthew; Liu, Yunbo; Keeler, Ethan G; Song, Mingli; Baran, Utku; Xi, Jiefeng; Sun, Ming-Ting; Wang, Ruikang; Li, Xingde; Lin, Lih Y

2015-01-01

This paper describes an endoscopic-inspired imaging system employing a micro-electromechanical system (MEMS) micromirror scanner to achieve beam scanning for optical coherence tomography (OCT) imaging. Miniaturization of a scanning mirror using MEMS technology can allow a fully functional imaging probe to be contained in a package sufficiently small for utilization in a working channel of a standard gastroesophageal endoscope. This work employs advanced image processing techniques to enhance the images acquired using the MEMS scanner to correct non-idealities in mirror performance. The experimental results demonstrate the effectiveness of the proposed technique.

MEMS scanning micromirror for optical coherence tomography

PubMed Central

Strathman, Matthew; Liu, Yunbo; Keeler, Ethan G.; Song, Mingli; Baran, Utku; Xi, Jiefeng; Sun, Ming-Ting; Wang, Ruikang; Li, Xingde; Lin, Lih Y.

2014-01-01

This paper describes an endoscopic-inspired imaging system employing a micro-electromechanical system (MEMS) micromirror scanner to achieve beam scanning for optical coherence tomography (OCT) imaging. Miniaturization of a scanning mirror using MEMS technology can allow a fully functional imaging probe to be contained in a package sufficiently small for utilization in a working channel of a standard gastroesophageal endoscope. This work employs advanced image processing techniques to enhance the images acquired using the MEMS scanner to correct non-idealities in mirror performance. The experimental results demonstrate the effectiveness of the proposed technique. PMID:25657887

MNE Scan: Software for real-time processing of electrophysiological data.

PubMed

Esch, Lorenz; Sun, Limin; Klüber, Viktor; Lew, Seok; Baumgarten, Daniel; Grant, P Ellen; Okada, Yoshio; Haueisen, Jens; Hämäläinen, Matti S; Dinh, Christoph

2018-06-01

Magnetoencephalography (MEG) and Electroencephalography (EEG) are noninvasive techniques to study the electrophysiological activity of the human brain. Thus, they are well suited for real-time monitoring and analysis of neuronal activity. Real-time MEG/EEG data processing allows adjustment of the stimuli to the subject's responses for optimizing the acquired information especially by providing dynamically changing displays to enable neurofeedback. We introduce MNE Scan, an acquisition and real-time analysis software based on the multipurpose software library MNE-CPP. MNE Scan allows the development and application of acquisition and novel real-time processing methods in both research and clinical studies. The MNE Scan development follows a strict software engineering process to enable approvals required for clinical software. We tested the performance of MNE Scan in several device-independent use cases, including, a clinical epilepsy study, real-time source estimation, and Brain Computer Interface (BCI) application. Compared to existing tools we propose a modular software considering clinical software requirements expected by certification authorities. At the same time the software is extendable and freely accessible. We conclude that MNE Scan is the first step in creating a device-independent open-source software to facilitate the transition from basic neuroscience research to both applied sciences and clinical applications. Copyright © 2018 Elsevier B.V. All rights reserved.

Three-dimensional machining of carbon nanotube forests using water-assisted scanning electron microscope processing

NASA Astrophysics Data System (ADS)

Rajabifar, Bahram; Kim, Sanha; Slinker, Keith; Ehlert, Gregory J.; Hart, A. John; Maschmann, Matthew R.

2015-10-01

We demonstrate that vertically aligned carbon nanotubes (CNTs) can be precisely machined in a low pressure water vapor ambient using the electron beam of an environmental scanning electron microscope. The electron beam locally damages the irradiated regions of the CNT forest and also dissociates the water vapor molecules into reactive species including hydroxyl radicals. These species then locally oxidize the damaged region of the CNTs. The technique offers material removal capabilities ranging from selected CNTs to hundreds of cubic microns. We study how the material removal rate is influenced by the acceleration voltage, beam current, dwell time, operating pressure, and CNT orientation. Milled cuts with depths between 0-100 microns are generated, corresponding to a material removal rate of up to 20.1 μm3/min. The technique produces little carbon residue and does not disturb the native morphology of the CNT network. Finally, we demonstrate direct machining of pyramidal surfaces and re-entrant cuts to create freestanding geometries.

Three-dimensional machining of carbon nanotube forests using water-assisted scanning electron microscope processing

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rajabifar, Bahram; Maschmann, Matthew R., E-mail: MaschmannM@missouri.edu; Kim, Sanha

2015-10-05

We demonstrate that vertically aligned carbon nanotubes (CNTs) can be precisely machined in a low pressure water vapor ambient using the electron beam of an environmental scanning electron microscope. The electron beam locally damages the irradiated regions of the CNT forest and also dissociates the water vapor molecules into reactive species including hydroxyl radicals. These species then locally oxidize the damaged region of the CNTs. The technique offers material removal capabilities ranging from selected CNTs to hundreds of cubic microns. We study how the material removal rate is influenced by the acceleration voltage, beam current, dwell time, operating pressure, andmore » CNT orientation. Milled cuts with depths between 0–100 microns are generated, corresponding to a material removal rate of up to 20.1 μm{sup 3}/min. The technique produces little carbon residue and does not disturb the native morphology of the CNT network. Finally, we demonstrate direct machining of pyramidal surfaces and re-entrant cuts to create freestanding geometries.« less

Adaptive optics optical coherence tomography at 120,000 depth scans/s for non-invasive cellular phenotyping of the living human retina

PubMed Central

Torti, Cristiano; Považay, Boris; Hofer, Bernd; Unterhuber, Angelika; Carroll, Joseph; Ahnelt, Peter Kurt; Drexler, Wolfgang

2012-01-01

This paper presents a successful combination of ultra-high speed (120,000 depth scans/s), ultra-high resolution optical coherence tomography with adaptive optics and an achromatizing lens for compensation of monochromatic and longitudinal chromatic ocular aberrations, respectively, allowing for non-invasive volumetric imaging in normal and pathologic human retinas at cellular resolution. The capability of this imaging system is demonstrated here through preliminary studies by probing cellular intraretinal structures that have not been accessible so far with in vivo, non-invasive, label-free imaging techniques, including pigment epithelial cells, micro-vasculature of the choriocapillaris, single nerve fibre bundles and collagenous plates of the lamina cribrosa in the optic nerve head. In addition, the volumetric extent of cone loss in two colour-blinds could be quantified for the first time. This novel technique provides opportunities to enhance the understanding of retinal pathogenesis and early diagnosis of retinal diseases. PMID:19997159

Enhanced materials from nature: nanocellulose from citrus waste.

PubMed

Mariño, Mayra; Lopes da Silva, Lucimara; Durán, Nelson; Tasic, Ljubica

2015-04-03

Nanocellulose is a relatively inexpensive, highly versatile bio-based renewable material with advantageous properties, including biodegradability and nontoxicity. Numerous potential applications of nanocellulose, such as its use for the preparation of high-performance composites, have attracted much attention from industry. Owing to the low energy consumption and the addition of significant value, nanocellulose extraction from agricultural waste is one of the best alternatives for waste treatment. Different techniques for the isolation and purification of nanocellulose have been reported, and combining these techniques influences the morphology of the resultant fibers. Herein, some of the extraction routes for obtaining nanocellulose from citrus waste are addressed. The morphology of nanocellulose was determined by Scanning Electron Microscopy (SEM) and Field Emission Scanning Electron Microscopy (FESEM), while cellulose crystallinity indexes (CI) from lyophilized samples were determined using solid-state Nuclear Magnetic Resonance (NMR) and X-Ray Diffraction (XRD) measurements. The resultant nanofibers had 55% crystallinity, an average diameter of 10 nm and a length of 458 nm.

Integrated approach to characterize fouling on a flat sheet membrane gravity driven submerged membrane bioreactor.

PubMed

Fortunato, Luca; Jeong, Sanghyun; Wang, Yiran; Behzad, Ali R; Leiknes, TorOve

2016-12-01

Fouling in membrane bioreactors (MBR) is acknowledged to be complex and unclear. An integrated characterization methodology was employed in this study to understand the fouling on a gravity-driven submerged MBR (GD-SMBR). It involved the use of different analytical tools, including optical coherence tomography (OCT), liquid chromatography with organic carbon detection (LC-OCD), total organic carbon (TOC), flow cytometer (FCM), adenosine triphosphate analysis (ATP) and scanning electron microscopy (SEM). The three-dimensional (3D) biomass morphology was acquired in a real-time through non-destructive and in situ OCT scanning of 75% of the total membrane surface directly in the tank. Results showed that the biomass layer was homogeneously distributed on the membrane surface. The amount of biomass was selectively linked with final destructive autopsy techniques. The LC-OCD analysis indicated the abundance of low molecular weight (LMW) organics in the fouling composition. Three different SEM techniques were applied to investigate the detailed fouling morphology on the membrane. Copyright © 2016 Elsevier Ltd. All rights reserved.

A Simple Technique for Securing Data at Rest Stored in a Computing Cloud

NASA Astrophysics Data System (ADS)

Sedayao, Jeff; Su, Steven; Ma, Xiaohao; Jiang, Minghao; Miao, Kai

"Cloud Computing" offers many potential benefits, including cost savings, the ability to deploy applications and services quickly, and the ease of scaling those application and services once they are deployed. A key barrier for enterprise adoption is the confidentiality of data stored on Cloud Computing Infrastructure. Our simple technique implemented with Open Source software solves this problem by using public key encryption to render stored data at rest unreadable by unauthorized personnel, including system administrators of the cloud computing service on which the data is stored. We validate our approach on a network measurement system implemented on PlanetLab. We then use it on a service where confidentiality is critical - a scanning application that validates external firewall implementations.

Practical applications of nondestructive materials characterization

NASA Astrophysics Data System (ADS)

Green, Robert E., Jr.

1992-10-01

Nondestructive evaluation (NDE) techniques are reviewed for applications to the industrial production of materials including microstructural, physical, and chemical analyses. NDE techniques addressed include: (1) double-pulse holographic interferometry for sealed-package leak testing; (2) process controls for noncontact metals fabrication; (3) ultrasonic detections of oxygen contamination in titanium welds; and (4) scanning acoustic microscopy for the evaluation of solder bonds. The use of embedded sensors and emerging NDE concepts provides the means for controlling the manufacturing and quality of quartz crystal resonators, nickel single-crystal turbine blades, and integrated circuits. Advances in sensor technology and artificial intelligence algorithms and the use of embedded sensors combine to make NDE technology highly effective in controlling industrial materials manufacturing and the quality of the products.

N-SCAN: new vibromodulation system for detection and monitoring of cracks and other contact-type defects

NASA Astrophysics Data System (ADS)

Donskoy, Dmitri; Ekimov, Alexander; Luzzato, Emile; Lottiaux, Jean-Louis; Stoupin, Stanislav; Zagrai, Andrei

2003-08-01

In recent years, innovative vibro-modulation technique has been introduced for detection of contact-type interfaces such as cracks, debondings, and delaminations. The technique utilizes the effect of nonlinear interaction of ultrasound and vibrations at the interface of the defect. Vibration varies on the contact area of the interface modulating passing through ultrasonic wave. The modulation manifests itself as additional side-band spectral components with the combination frequencies in the spectrum of the received signal. The presence of these components allows for detection and differentiation of the contact-type defects from other structural and material inhomogeneities. Vibro-modulation technique has been implemented in N-SCAN damage detection system. The system consists of a digital synthesizer, high and low frequency amplifiers, a magnetostrictive shaker, ultrasonic transducers and a PC-based data acquisition/processing station with N-SCAN software. The ability of the system to detect contact-type defects was experimentally verified using specimens of simple and complex geometries made of steel, aluminum, composites and other structural materials. N-SCAN proved to be very effective for nondestructive testing of full-scale structures ranging from 24 foot-long gun barrels to stainless steel pipes used in nuclear power plants. Among advantages of the system are applicability for the wide range of structural materials and for structures with complex geometries, real time data processing, convenient interface for system operation, simplicity of interpretation of results, no need for sensor scanning along structure, onsite inspection of large structures at a fraction of time as compared with conventional techniques. This paper describes the basic principles of nonlinear vibro-modulation NDE technique, some theoretical background for nonlinear interaction and justification of signal processing algorithm. It is also presents examples of practical implementation and application of the technique.

Nanoscience

DTIC Science & Technology

2011-07-22

L., Upgrading of Existing X - Ray Photoelectron Spectrometer Capabilities for Development and Analysis of Novel Energetic NanoCluster materials (DURIP...References From the Technical Reports database Allara, David L., Pennsylvania State University, Upgrading of Existing X - Ray Photoelectron...Scanning probe  X - ray Of these techniques, the most popularly used is the scanning probe, also known as the Dip-Pen Nanolithography (DPN) technique

Adaption of synchronously scanned luminescence spectroscopy to organic-rich fluid inclusion microanalysis

DOE Office of Scientific and Technical Information (OSTI.GOV)

Musgrave, J.A.; Carey, R.G.; Janecky, D.R.

1994-06-01

The instrumentation, the luminescence microprobe, and synchronously scanned luminescence spectroscopy technique described here can be used to classify microliter quantities of oil such as those in fluid inclusions in cements from petroleum reservoirs. It is primarily constructed to obtain synchronously scanned luminescence spectra from microscopic sized samples to characterize the organic classes of compounds that predominate. At present no other technique can so readily analyze a single oil-bearing fluid inclusion. The data collected from the technique are pertinent to evaluating systems and providing quantitative data for solving problems in oil migration and maturation determinations, oil-to-oil and oil-to-source correlations, oil degradation,more » and episodes and chemistry of cementation.« less

Surface study of graphene ink for fine solid lines printed on BOPP Substrate in micro-flexographic printing using XPS analysis technique

NASA Astrophysics Data System (ADS)

Hassan, S.; Yusof, M. S.; Embong, Z.; Ding, S.; Maksud, M. I.

2018-01-01

Micro-flexographic printing is a combination of flexography and micro-contact printing technique. It is a new printing method for fine solid lines printing purpose. Graphene material has been used as depositing agent or printing ink in other printing technique like inkjet printing. This graphene ink is printed on biaxially oriented polypropylene (BOPP) by using Micro-flexographic printing technique. The choose of graphene as a printing ink is due to its wide application in producing electronic and micro-electronic devices such as Radio-frequency identification (RFID) and printed circuit board. The graphene printed on the surface of BOPP substrate was analyzed using X-Ray Photoelectron Spectroscopy (XPS). The positions for each synthetic component in the narrow scan are referred to the electron binding energy (eV). This research is focused on two narrow scan regions which are C 1s and O 1s. Further discussion of the narrow scan spectrum will be explained in detail. From the narrow scan analysis, it is proposed that from the surface adhesive properties of graphene, it is suitable as an alternative printing ink medium for Micro-flexographic printing technique in printing multiple fine solid lines at micro to nano scale feature.

Mapping piezoelectric response in nanomaterials using a dedicated non-destructive scanning probe technique.

PubMed

Calahorra, Yonatan; Smith, Michael; Datta, Anuja; Benisty, Hadas; Kar-Narayan, Sohini

2017-12-14

There has been tremendous interest in piezoelectricity at the nanoscale, for example in nanowires and nanofibers where piezoelectric properties may be enhanced or controllably tuned, thus necessitating robust characterization techniques of piezoelectric response in nanomaterials. Piezo-response force microscopy (PFM) is a well-established scanning probe technique routinely used to image piezoelectric/ferroelectric domains in thin films, however, its applicability to nanoscale objects is limited due to the requirement for physical contact with an atomic force microscope (AFM) tip that may cause dislocation or damage, particularly to soft materials, during scanning. Here we report a non-destructive PFM (ND-PFM) technique wherein the tip is oscillated into "discontinuous" contact during scanning, while applying an AC bias between tip and sample and extracting the piezoelectric response for each contact point by monitoring the resulting localized deformation at the AC frequency. ND-PFM is successfully applied to soft polymeric (poly-l-lactic acid) nanowires, as well as hard ceramic (barium zirconate titanate-barium calcium titanate) nanowires, both previously inaccessible by conventional PFM. Our ND-PFM technique is versatile and compatible with commercial AFMs, and can be used to correlate piezoelectric properties of nanomaterials with their microstructural features thus overcoming key characterisation challenges in the field.

A novel approach to surveying sturgeon using side-scan sonar and occupancy modeling

USGS Publications Warehouse

Flowers, H. Jared; Hightower, Joseph E.

2013-01-01

Technological advances represent opportunities to enhance and supplement traditional fisheries sampling approaches. One example with growing importance for fisheries research is hydroacoustic technologies such as side-scan sonar. Advantages of side-scan sonar over traditional techniques include the ability to sample large areas efficiently and the potential to survey fish without physical handling-important for species of conservation concern, such as endangered sturgeons. Our objectives were to design an efficient survey methodology for sampling Atlantic Sturgeon Acipenser oxyrinchus by using side-scan sonar and to developmethods for analyzing these data. In North Carolina and South Carolina, we surveyed six rivers thought to contain varying abundances of sturgeon by using a combination of side-scan sonar, telemetry, and video cameras (i.e., to sample jumping sturgeon). Lower reaches of each river near the saltwater-freshwater interface were surveyed on three occasions (generally successive days), and we used occupancy modeling to analyze these data.We were able to detect sturgeon in five of six rivers by using these methods. Side-scan sonar was effective in detecting sturgeon, with estimated gear-specific detection probabilities ranging from 0.2 to 0.5 and river-specific occupancy estimates (per 2-km river segment) ranging from 0.0 to 0.8. Future extensions of this occupancy modeling framework will involve the use of side-scan sonar data to assess sturgeon habitat and abundance in different river systems.

Assessment of a Microsoft Kinect-based 3D scanning system for taking body segment girth measurements: a comparison to ISAK and ISO standards.

PubMed

Clarkson, Sean; Wheat, Jon; Heller, Ben; Choppin, Simon

2016-01-01

Use of anthropometric data to infer sporting performance is increasing in popularity, particularly within elite sport programmes. Measurement typically follows standards set by the International Society for the Advancement of Kinanthropometry (ISAK). However, such techniques are time consuming, which reduces their practicality. Schranz et al. recently suggested 3D body scanners could replace current measurement techniques; however, current systems are costly. Recent interest in natural user interaction has led to a range of low-cost depth cameras capable of producing 3D body scans, from which anthropometrics can be calculated. A scanning system comprising 4 depth cameras was used to scan 4 cylinders, representative of the body segments. Girth measurements were calculated from the 3D scans and compared to gold standard measurements. Requirements of a Level 1 ISAK practitioner were met in all 4 cylinders, and ISO standards for scan-derived girth measurements were met in the 2 larger cylinders only. A fixed measurement bias was identified that could be corrected with a simple offset factor. Further work is required to determine comparable performance across a wider range of measurements performed upon living participants. Nevertheless, findings of the study suggest such a system offers many advantages over current techniques, having a range of potential applications.

Comparison of scatter rejection and low-contrast performance of scan equalization digital radiography (SEDR), slot-scan digital radiography, and full-field digital radiography systems for chest phantom imaging

DOE Office of Scientific and Technical Information (OSTI.GOV)

Liu Xinming; Shaw, Chris C.; Lai, Chao-Jen

Purpose: To investigate and compare the scatter rejection properties and low-contrast performance of the scan equalization digital radiography (SEDR) technique to the slot-scan and conventional full-field digital radiography techniques for chest imaging. Methods: A prototype SEDR system was designed and constructed with an a-Se flat-panel (FP) detector to improve image quality in heavily attenuating regions of an anthropomorphic chest phantom. Slot-scanning geometry was used to reject scattered radiation without attenuating primary x rays. The readout scheme of the FP was modified to erase accumulated scatter signals prior to image readout. A 24-segment beam width modulator was developed to regulate x-raymore » exposures regionally and compensate for the low x-ray flux in heavily attenuating regions. To measure the scatter-to-primary ratios (SPRs), a 2 mm thick lead plate with a 2-D array of aperture holes was used to measure the primary signals, which were then subtracted from those obtained without the lead plate to determine scatter components. A 2-D array of aluminum beads (3 mm in diameter) was used as the low-contrast objects to measure the contrast ratios (CRs) and contrast-to-noise ratios (CNRs) for evaluating the low-contrast performance in chest phantom images. A set of two images acquired with the same techniques were subtracted from each other to measure the noise levels. SPRs, CRs, and CNRs of the SEDR images were measured in four anatomical regions of chest phantom images and compared to those of slot-scan images and full-field images acquired with and without antiscatter grid. Results: The percentage reduction of SPR (percentage of SPRs reduced with scatter removal/rejection methods relative to that for nongrid full-field imaging) averaged over four anatomical regions was measured to be 80%, 83%, and 71% for SEDR, slot-scan, and full-field with grid, respectively. The average CR over four regions was found to improve over that for nongrid full-field imaging by 259%, 279%, and 145% for SEDR, slot-scan, and full-field with grid, respectively. The average CNR over four regions was found to improve over that for nongrid full-field imaging by 201% for SEDR as compared to 133% for the slot-scan technique and 14% for the antiscatter grid method. Conclusions: Both SEDR and slot-scan techniques outperformed the antiscatter grid method used in standard full-field radiography. For imaging with the same effective exposure, the SEDR technique offers no advantage over the slot-scan method in terms of SPRs and CRs. However, it improves CNRs significantly, especially in heavily attenuating regions. The improvement of low-contrast performance may help improve the detection of the lung nodules or other abnormalities and may offer SEDR the potential for dose reduction in chest radiography.« less

Integrated instrument for dynamic light scattering and natural fluorescence measurements

NASA Astrophysics Data System (ADS)

Rovati, Luigi; Pollonini, Luca; Ansari, Rafat R.

2001-06-01

Over the past two decades, great efforts have been made in ophthalmology to use optical techniques based on dynamic light scattering and tissue natural fluorescence for early (at molecular level) diagnosis of ocular pathologies. In our previous studies, the relationship between the corneal AF and DLS decay widths of ocular tissues were established by performing measurements on diabetes mellitus patients. In those studies, corneal AF mean intensities were significantly correlated with DLS decay width measurements for each diabetic retinopathy grade in the vitreous and in the cornea. This suggested that the quality of the diagnosis could be significantly improved by properly combining these two powerful techniques into a single instrument. Our approach is based on modifying a commercial scanning ocular fluorometer (Fluorotron Master, Ocumetrics Inc., CA, USA) to include both techniques in the same scanning unit. This configuration provides both DLS and AF real time measurements from the same ocular volume: they can be located in each section of the optical axis of the eye from the cornea to the retina. In this paper, the optical setup of the new system is described and preliminary in-vitro and in-vivo measurements are presented.

Identification and quantitation of semi-crystalline microplastics using image analysis and differential scanning calorimetry.

PubMed

Rodríguez Chialanza, Mauricio; Sierra, Ignacio; Pérez Parada, Andrés; Fornaro, Laura

2018-06-01

There are several techniques used to analyze microplastics. These are often based on a combination of visual and spectroscopic techniques. Here we introduce an alternative workflow for identification and mass quantitation through a combination of optical microscopy with image analysis (IA) and differential scanning calorimetry (DSC). We studied four synthetic polymers with environmental concern: low and high density polyethylene (LDPE and HDPE, respectively), polypropylene (PP), and polyethylene terephthalate (PET). Selected experiments were conducted to investigate (i) particle characterization and counting procedures based on image analysis with open-source software, (ii) chemical identification of microplastics based on DSC signal processing, (iii) dependence of particle size on DSC signal, and (iv) quantitation of microplastics mass based on DSC signal. We describe the potential and limitations of these techniques to increase reliability for microplastic analysis. Particle size demonstrated to have particular incidence in the qualitative and quantitative performance of DSC signals. Both, identification (based on characteristic onset temperature) and mass quantitation (based on heat flow) showed to be affected by particle size. As a result, a proper sample treatment which includes sieving of suspended particles is particularly required for this analytical approach.

Complete measurement of spatiotemporally complex multi-spatial-mode ultrashort pulses from multimode optical fibers using delay-scanned wavelength-multiplexed holography.

PubMed

Zhu, Ping; Jafari, Rana; Jones, Travis; Trebino, Rick

2017-10-02

We introduce a simple delay-scanned complete spatiotemporal intensity-and-phase measurement technique based on wavelength-multiplexed holography to characterize long, complex pulses in space and time. We demonstrate it using pulses emerging from multi-mode fiber. This technique extends the temporal range and spectral resolution of the single-frame STRIPED FISH technique without using an otherwise-required expensive ultranarrow-bandpass filter. With this technique, we measured the complete intensity and phase of up to ten fiber modes from a multi-mode fiber (normalized frequency V ≈10) over a ~3ps time range. Spatiotemporal complexities such as intermodal delay, modal dispersion, and material dispersion were also intuitively displayed by the retrieved results. Agreement between the reconstructed color movies and the monitored time-averaged spatial profiles confirms the validity to this delay-scanned STRIPED FISH method.

Characterization of the host response to the myxosporean parasite, Ceratomyxa shasta (Noble), by histology, scanning electron microscopy, and immunological techniques

USGS Publications Warehouse

Bartholomew, J.L.; Smith, C.E.; Rohovec, J.S.; Fryer, J.L.

1989-01-01

The tissue response of Salmo gairdneri Richardson, against the myxosporean parasite. Ceratomyxa shasta (Noble), was investigated using histological techniques, scanning electron microscopy and immunological methods. The progress of infection in C. shasta-susceptible and resistant steelhead and rainbow trout was examined by standard histological techniques and by indirect fluorescent antibody methods using monoclonal antibodies directed against C. shasta antigens. Trophozoite stages were first observed in the posterior intestine and there was indication that resistance was due to the inability of the parasite to penetrate this tissue rather than to an inflammatory response. Examination of a severely infected intestine by scanning electron microscopy showed extensive destruction of the mucosal folds of the posterior intestine. Western blotting and indirect fluorescent antibody techniques were used to investigate the immunological component of the host response. No antibodies specific for C. shasta were detected by either method.

Z-scan: A simple technique for determination of third-order optical nonlinearity

DOE Office of Scientific and Technical Information (OSTI.GOV)

Singh, Vijender, E-mail: chahal-gju@rediffmail.com; Aghamkar, Praveen, E-mail: p-aghamkar@yahoo.co.in

Z-scan is a simple experimental technique to measure intensity dependent nonlinear susceptibilities of third-order nonlinear optical materials. This technique is used to measure the sign and magnitude of both real and imaginary part of the third order nonlinear susceptibility (χ{sup (3)}) of nonlinear optical materials. In this paper, we investigate third-order nonlinear optical properties of Ag-polymer composite film by using single beam z-scan technique with Q-switched, frequency doubled Nd: YAG laser (λ=532 nm) at 5 ns pulse. The values of nonlinear absorption coefficient (β), nonlinear refractive index (n{sub 2}) and third-order nonlinear optical susceptibility (χ{sup (3)}) of permethylazine were found to bemore » 9.64 × 10{sup −7} cm/W, 8.55 × 10{sup −12} cm{sup 2}/W and 5.48 × 10{sup −10} esu, respectively.« less

Ensuring safety of implanted devices under MRI using reversed RF polarization.

PubMed

Overall, William R; Pauly, John M; Stang, Pascal P; Scott, Greig C

2010-09-01

Patients with long-wire medical implants are currently prevented from undergoing magnetic resonance imaging (MRI) scans due to the risk of radio frequency (RF) heating. We have developed a simple technique for determining the heating potential for these implants using reversed radio frequency (RF) polarization. This technique could be used on a patient-to-patient basis as a part of the standard prescan procedure to ensure that the subject's device does not pose a heating risk. By using reversed quadrature polarization, the MR scan can be sensitized exclusively to the potentially dangerous currents in the device. Here, we derive the physical principles governing the technique and explore the primary sources of inaccuracy. These principles are verified through finite-difference simulations and through phantom scans of implant leads. These studies demonstrate the potential of the technique for sensitively detecting potentially dangerous coupling conditions before they can do any harm. 2010 Wiley-Liss, Inc.

Definition of mutually optimum NDI and proof test criteria for 2219 aluminum pressure vessels. Volume 3: Applications to rail defect evaluation

NASA Technical Reports Server (NTRS)

Schwartzberg, F. R.; Toth, C., Jr.; King, R. G.; Todd, P. H., Jr.

1979-01-01

The technique for inspection of railroad rails containing transverse fissure defects was discussed. Both pulse-echo and pitch-catch inspection techniques were used. The pulse-echo technique results suggest that a multiple-scan approach using varying angles of inclination, three-surface scanning, and dual-direction traversing may offer promise of characterization of transverse defects. Because each scan is likely to produce a reflection indicating only a portion of the defect, summing of the individual reflections must be used to obtain a reasonably complete characterization of the defect. The ability of the collimated pitch-catch technique to detect relatively small amounts of flaw growth was shown. The method has a problem in characterizing the portions of the defect near the top surface or web intersection. The work performed was a preliminary evaluation of the prospects for automated mapping of rail flaws.

A Novel Microcharacterization Technique in the Measurement of Strain and Orientation Gradient in Advanced Materials

NASA Technical Reports Server (NTRS)

Garmestai, H.; Harris, K.; Lourenco, L.

1997-01-01

Representation of morphology and evolution of the microstructure during processing and their relation to properties requires proper experimental techniques. Residual strains, lattice distortion, and texture (micro-texture) at the interface and the matrix of a layered structure or a functionally gradient material and their variation are among parameters important in materials characterization but hard to measure with present experimental techniques. Current techniques available to measure changes in interred material parameters (residual stress, micro-texture, microplasticity) produce results which are either qualitative or unreliable. This problem becomes even more complicated in the case of a temperature variation. These parameters affect many of the mechanical properties of advanced materials including stress-strain relation, ductility, creep, and fatigue. A review of some novel experimental techniques using recent advances in electron microscopy is presented here to measure internal stress, (micro)texture, interracial strength and (sub)grain formation and realignment. Two of these techniques are combined in the chamber of an Environmental Scanning Electron Microscope to measure strain and orientation gradients in advanced materials. These techniques which include Backscattered Kikuchi Diffractometry (BKD) and Microscopic Strain Field Analysis are used to characterize metallic and intermetallic matrix composites and superplastic materials. These techniques are compared with the more conventional x-ray diffraction and indentation techniques.

Imaging interactions of metal oxide nanoparticles with macrophage cells by ultra-high resolution scanning electron microscopy techniques†

PubMed Central

Plascencia-Villa, Germán; Starr, Clarise R.; Armstrong, Linda S.; Ponce, Arturo

2016-01-01

Use of engineered metal oxide nanoparticles in a plethora of biological applications and custom products has warned about some possible dose-dependent cytotoxic effects. Macrophages are key components of the innate immune system used to study possible toxic effects and internalization of different nanoparticulate materials. In this work, ultra-high resolution field emission scanning electron microscopy (FE-SEM) was used to offer new insights into the dynamical processes of interaction of nanomaterials with macrophage cells dosed with different concentrations of metal oxide nanoparticles (CeO2, TiO2 and ZnO). The versatility of FE-SEM has allowed obtaining a detailed characterization of processes of adsorption and endocytosis of nanoparticles, by using advanced analytical and imaging techniques on complete unstained uncoated cells, including secondary electron imaging, high-sensitive backscattered electron imaging, X-ray microanalysis and stereoimaging. Low voltage BF/DF-STEM confirmed nanoparticle adsorption and internalization into endosomes of CeO2 and TiO2, whereas ZnO develop apoptosis after 24 h of interaction caused by dissolution and invasion of cell nucleus. Ultra-high resolution scanning electron microscopy techniques provided new insights into interactions of inorganic nanoparticles with macrophage cells with high spatial resolution. PMID:23023106

Direct measurement of the Goos-Hänchen shift using a scanning quadrant detector and a polarization maintaining fiber.

PubMed

Yallapragada, Venkata Jayasurya; Mulay, Gajendra L; Rao, Ch N; Ravishankar, Ajith P; Achanta, Venu Gopal

2016-10-01

High precision measurements of optical beam shifts are important in various fields including sensing, atomic force microscopy, and measuring beam shifts at interfaces. Sub-micron shifts are generally measured by indirect techniques such as weak measurements. We demonstrate a straightforward and robust measurement scheme for the shift, based on a scanning quadrant photodiode (QPD) that is biased using a low noise electronic circuit. The shift is measured with respect to a reference beam that is co-propagating with the signal beam. Thus, the shift of the signal beam is readout directly as the difference between the x-intercepts of the QPD scan plot of the signal and reference beams versus the position of the detector. To measure the beam shift, we use polarization multiplexing scheme where the p-polarized signal and s-polarized reference beams are modulated at two different frequencies and co-launched into a polarization-maintaining fiber. Both the signal and reference beam positions are readout by two lock-in amplifiers simultaneously. In order to demonstrate the utility of this method, we perform a direct measurement of Goos-Hänchen shift of a beam that is reflected from a plane gold surface. Accuracy of 150 nm is achieved using this technique.

Direct measurement of the Goos-Hänchen shift using a scanning quadrant detector and a polarization maintaining fiber

NASA Astrophysics Data System (ADS)

Yallapragada, Venkata Jayasurya; Mulay, Gajendra L.; Rao, Ch. N.; Ravishankar, Ajith P.; Achanta, Venu Gopal

2016-10-01

High precision measurements of optical beam shifts are important in various fields including sensing, atomic force microscopy, and measuring beam shifts at interfaces. Sub-micron shifts are generally measured by indirect techniques such as weak measurements. We demonstrate a straightforward and robust measurement scheme for the shift, based on a scanning quadrant photodiode (QPD) that is biased using a low noise electronic circuit. The shift is measured with respect to a reference beam that is co-propagating with the signal beam. Thus, the shift of the signal beam is readout directly as the difference between the x-intercepts of the QPD scan plot of the signal and reference beams versus the position of the detector. To measure the beam shift, we use polarization multiplexing scheme where the p-polarized signal and s-polarized reference beams are modulated at two different frequencies and co-launched into a polarization-maintaining fiber. Both the signal and reference beam positions are readout by two lock-in amplifiers simultaneously. In order to demonstrate the utility of this method, we perform a direct measurement of Goos-Hänchen shift of a beam that is reflected from a plane gold surface. Accuracy of 150 nm is achieved using this technique.

A novel approach to measure elemental concentrations in cation exchange resins using XRF-scanning technique, and its potential in water pollution studies

NASA Astrophysics Data System (ADS)

Huang, Jyh-Jaan; Lin, Sheng-Chi; Löwemark, Ludvig; Liou, Ya-Hsuan; Chang, Queenie; Chang, Tsun-Kuo; Wei, Kuo-Yen; Croudace, Ian W.

2016-04-01

X-ray fluorescence (XRF) core-scanning is a fast, and convenient technique to assess elemental variations for a wide variety of research topics. However, the XRF scanning counts are often considered a semi-quantitative measurement due to possible absorption or scattering caused by down core variability in physical properties. To overcome this problem and extend the applications of XRF-scanning to water pollution studies, we propose to use cation exchange resin (IR-120) as an "elemental carrier", and to analyze the resins using the Itrax-XRF core scanner. The use of resin minimizes the matrix effects during the measurements, and can be employed in the field in great numbers due to its low price. Therefore, the fast, and non-destructive XRF-scanning technique can provide a quick and economical method to analyze environmental pollution via absorption in the resin. Five standard resin samples were scanned by the Itrax-XRF core scanner at different exposure times (1 s, 5 s, 15 s, 30 s, 100 s) to allow the comparisons of scanning counts with the absolute concentrations. The regression lines and correlation coefficients of elements that are generally used in pollution studies (Ca, Ti, Cr, Ni, Cu, Zn, and Pb) were examined for the different exposure times. The result shows that within the test range (from few ppm to thousands ppm), the correlation coefficients are all higher than 0.97, even at the shortest exposure time (1 s). Therefore, we propose to use this method in the field to monitor for example sewage disposal events. The low price of resin, and fast, multi elements and precise XRF-scanning technique provide a viable, cost- and time-effective approach that allows large sample numbers to be processed. In this way, the properties and sources of wastewater pollution can be traced for the purpose of environmental monitoring and environmental forensics.

Detection of monoclonal immunoglobulin heavy chain gene rearrangement (FR3) in Thai malignant lymphoma by High Resolution Melting curve analysis.

PubMed

Kummalue, Tanawan; Chuphrom, Anchalee; Sukpanichanant, Sanya; Pongpruttipan, Tawatchai; Sukpanichanant, Sathien

2010-05-19

Malignant lymphoma, especially non-Hodgkin lymphoma, is one of the most common hematologic malignancies in Thailand. The diagnosis of malignant lymphoma is often problematic, especially in early stages of the disease. Detection of antigen receptor gene rearrangement including T cell receptor (TCR) and immunoglobulin heavy chain (IgH) by polymerase chain reaction followed by heteroduplex has currently become standard whereas fluorescent fragment analysis (GeneScan) has been used for confirmation test. In this study, three techniques had been compared: thermocycler polymerase chain reaction (PCR) followed by heteroduplex and polyacrylamide gel electrophoresis, GeneScan analysis, and real time PCR with High Resolution Melting curve analysis (HRM). The comparison was carried out with DNA extracted from paraffin embedded tissues diagnosed as B- cell non-Hodgkin lymphoma. Specific PCR primers sequences for IgH gene variable region 3, including fluorescence labeled IgH primers were used and results were compared with HRM. In conclusion, the detection IgH gene rearrangement by HRM in the LightCycler System showed potential for distinguishing monoclonality from polyclonality in B-cell non-Hodgkin lymphoma. Malignant lymphoma, especially non-Hodgkin lymphoma, is one of the most common hematologic malignancies in Thailand. The incidence rate as reported by Ministry of Public Health is 3.1 per 100,000 population in female whereas the rate in male is 4.5 per 100,000 population 1. At Siriraj Hospital, the new cases diagnosed as malignant lymphoma were 214.6 cases/year 2. The diagnosis of malignant lymphoma is often problematic, especially in early stages of the disease. Therefore, detection of antigen receptor gene rearrangement including T cell receptor (TCR) and immunoglobulin heavy chain (IgH) by polymerase chain reaction (PCR) assay has recently become a standard laboratory test for discrimination of reactive from malignant clonal lymphoproliferation 34. Analyzing DNA extracted from formalin-fixed, paraffin-embedded tissues by multiplex PCR techniques is more rapid, accurate and highly sensitive. Measuring the size of the amplicon from PCR analysis could be used to diagnose malignant lymphoma with monoclonal pattern showing specific and distinct bands detected on acrylamide gel electrophoresis. However, this technique has some limitations and some patients might require a further confirmation test such as GeneScan or fragment analysis 56.GeneScan technique or fragment analysis reflects size and peak of DNA by using capillary gel electrophoresis. This technique is highly sensitive and can detect 0.5-1% of clonal lymphoid cells. It measures the amplicons by using various fluorescently labeled primers at forward or reverse sides and a specific size standard. Using a Genetic Analyzer machine and GeneMapper software (Applied Bioscience, USA), the monoclonal pattern revealed one single, sharp and high peak at the specific size corresponding to acrylamide gel pattern, whereas the polyclonal pattern showed multiple and small peak condensed at the same size standard. This technique is the most sensitive and accurate technique; however, it usually requires high technical experience and is also of high cost 7. Therefore, rapid and more cost effective technique are being sought.LightCycler PCR performs the diagnostic detection of amplicon via melting curve analysis within 2 hours with the use of a specific dye 89. This dye consists of two types: one known as SYBR-Green I which is non specific and the other named as High Resolution Melting analysis (HRM) which is highly sensitive, more accurate and stable. Several reports demonstrated that this new instrument combined with DNA intercalating dyes can be used to discriminate sequence changes in PCR amplicon without manual handling of PCR product 1011. Therefore, current investigations using melting curve analysis are being developed 1213.In this study, three different techniques were compared to evaluate the suitability of LightCycler PCR with HRM as the clonal diagnostic tool for IgH gene rearrangement in B-cell non-Hogdkin lymphoma, i.e. thermocycler PCR followed by heteroduplex analysis and PAGE, GeneScan analysis and LightCycler PCR with HRM.

Feasibility of High-Resolution Pulse-Echo Techniques for Automobile Tire Inspection

DOT National Transportation Integrated Search

1973-06-01

The report presents ultrasonic A-scan reflection oscillograms and B-scan one-dimensional scanning displays for small sections of automobile tires, and for tire-like rubber and cord composite structures, using impulse excitation of 1-MHz and 5-MHz tra...

Key Role of M.G. Nakhodkin’s Insight and Inspiration in Development of UHV STM-Related Techniques and Methods

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lyubinetsky, Igor

2015-02-15

In this contribution I briefly describe my joint efforts and experiences with M.G. Nakhodkin in the field of scanning tunneling microscopy (STM) including a construction of the home-built microscopes, application of this technique in various scientific endevours, as well as fruitfull and enlightening discusions. Our co-operation was focused on the novel aspects of STM probes preparation and conditioning, coupling the STM junction with laser irradiation, STM-based nanolithography, and also on collaboration at the international scale with M.G. Nakhodkin and members of his scientific group.

Measurement of total-body cobalt-57 vitamin B12 absorption with a gamma camera.

PubMed

Cardarelli, J A; Slingerland, D W; Burrows, B A; Miller, A

1985-08-01

Previously described techniques for the measurement of the absorption of [57Co]vitamin B12 by total-body counting have required an iron room equipped with scanning or multiple detectors. The present study uses simplifying modifications which make the technique more available and include the use of static geometry, the measurement of body thickness to correct for attenuation, a simple formula to convert the capsule-in-air count to a 100% absorption count, and finally the use of an adequately shielded gamma camera obviating the need of an iron room.

A comparative review of optical surface contamination assessment techniques

NASA Technical Reports Server (NTRS)

Heaney, James B.

1987-01-01

This paper will review the relative sensitivities and practicalities of the common surface analytical methods that are used to detect and identify unwelcome adsorbants on optical surfaces. The compared methods include visual inspection, simple reflectometry and transmissiometry, ellipsometry, infrared absorption and attenuated total reflectance spectroscopy (ATR), Auger electron spectroscopy (AES), scanning electron microscopy (SEM), secondary ion mass spectrometry (SIMS), and mass accretion determined by quartz crystal microbalance (QCM). The discussion is biased toward those methods that apply optical thin film analytical techniques to spacecraft optical contamination problems. Examples are cited from both ground based and in-orbit experiments.

Status of the Neutron Imaging and Diffraction Instrument IMAT

NASA Astrophysics Data System (ADS)

Kockelmann, Winfried; Burca, Genoveva; Kelleher, Joe F.; Kabra, Saurabh; Zhang, Shu-Yan; Rhodes, Nigel J.; Schooneveld, Erik M.; Sykora, Jeff; Pooley, Daniel E.; Nightingale, Jim B.; Aliotta, Francesco; Ponterio, Rosa C.; Salvato, Gabriele; Tresoldi, Dario; Vasi, Cirino; McPhate, Jason B.; Tremsin, Anton S.

A cold neutron imaging and diffraction instrument, IMAT, is currently being constructed at the ISIS second target station. IMAT will capitalize on time-of-flight transmission and diffraction techniques available at a pulsed neutron source. Analytical techniques will include neutron radiography, neutron tomography, energy-selective neutron imaging, and spatially resolved diffraction scans for residual strain and texture determination. Commissioning of the instrument will start in 2015, with time-resolving imaging detectors and two diffraction detector prototype modules. IMAT will be operated as a user facility for material science applications and will be open for developments of time-of-flight imaging methods.

Auger spectroscopy of fracture surfaces of ceramics

NASA Technical Reports Server (NTRS)

Marcus, H. L.; Harris, J. M.; Szalkowski, F. J.

1974-01-01

Results of Auger electron spectroscopy (AES) studies of fracture surfaces in a series of ceramic materials, including Al2O3, MgO, and Si3N4, which were formed using different processing techniques. AES on the fractured surface of a lunar sample is also discussed. Scanning electron micrograph fractography is used to relate the surface chemistry to the failure mode. Combined argon ion sputtering and AES studies demonstrate the local variations in chemistry near the fracture surface. The problems associated with doing AES in insulators are also discussed, and the experimental techniques directed toward solving them are described.

Development of an X-ray prism for a combined diffraction enhanced imaging and fluorescence imaging system

NASA Astrophysics Data System (ADS)

Bewer, Brian E.

Analyzer crystal based imaging techniques such as diffraction enhanced imaging (DEI) and multiple imaging radiography (MIR) utilize the Bragg peak of perfect crystal diffraction to convert angular changes into intensity changes. These X-ray techniques extend the capability of conventional radiography, which derives image contrast from absorption, by providing a large change in intensity for a small angle change introduced by the X-ray beam traversing the sample. Objects that have very little absorption contrast may have considerable refraction and ultra small angle X-ray scattering (USAXS) contrast thus improving visualization and extending the utility of X-ray imaging. To improve on the current DEI technique this body of work describes the design of an X-ray prism (XRP) included in the imaging system which allows the analyzer crystal to be aligned anywhere on the rocking curve without moving the analyzer from the Bragg angle. By using the XRP to set the rocking curve alignment rather than moving the analyzer crystal physically the needed angle sensitivity is changed from muradians for direct mechanical movement of the analyzer crystal to milliradian control for movement the XRP angle. In addition to using an XRP for the traditional DEI acquisition method of two scans on opposite sides of the rocking curve preliminary tests will be presented showing the potential of using an XRP to scan quickly through the entire rocking curve. This has the benefit of collecting all the required data for image reconstruction in a single fast measurement thus removing the occurrence of motion artifacts for each point or line used during a scan. The XRP design is also intended to be compatible with combined imaging systems where more than one technique is used to investigate a sample. Candidates for complimentary techniques are investigated and measurements from a combined X-ray imaging system are presented.

Diagnostic Accuracy of B-mode USG and Doppler Scan for Ovarian Lesions

PubMed Central

Agarwal, Vinish Kumar

2016-01-01

Introduction Ultrasonography (USG) is considered as the primary imaging modality for confirmation of ovarian mass and to differentiate them in to benign or malignant. Aim The present study was conducted with the aim to evaluate accuracy of B- mode USG and Doppler scan (Colour Doppler + Spectral Doppler) for ovarian lesions. Materials and Methods The patients included in the study were from those referred with either palpable adnexal mass or incidentally detected adnexal masses. Total 250 women were evaluated by USG, Doppler scan. Only fifty patients who had true ovarian mass intraoperatively and on histopathology were included in study, rest masses were excluded. Study parameters were morphological indexing on B- Mode USG, flow study, vessel arrangement, and vessel morphology and vessel location in Colour Doppler and resistive index and pulsatility index in spectral Doppler. Results Total 50 women were included in present study. Out of these 46% were pre-menopausal while 54% were menopaused women, 66.7% of post-menopausal women had malignant ovarian masses compared to 8.7% of premenopausal. Sensitivity, specificity, positive predictive value and negative predictive value of B-Mode USG for ovarian masses were 94.44%, 48.15%, 54.84% and 92.86% respectively, with p-value = 0.007, while sensitivity, specificity, positive predictive value and negative predictive value of Doppler scan were 85%, 90%, 85% and 90% respectively, with p-value = 0.0001. Conclusion USG and its different techniques are accepted as the primary imaging modality for early stage diagnosis of an ovarian malignancy. Statistical analysis suggests that Doppler Scan (Colour + Spectral) was more accurate (88%) than B-Mode USG (67%), but author is in view that both of these modalities should be used in conjunction to screen the ovarian lesions. PMID:27790544

Comparison of denture base adaptation between CAD-CAM and conventional fabrication techniques.

PubMed

Goodacre, Brian J; Goodacre, Charles J; Baba, Nadim Z; Kattadiyil, Mathew T

2016-08-01

Currently no data comparing the denture base adaptation of CAD-CAM and conventional denture processing techniques have been reported. The purpose of this in vitro study was to compare the denture base adaptation of pack and press, pour, injection, and CAD-CAM techniques for fabricating dentures to determine which process produces the most accurate and reproducible adaptation. A definitive cast was duplicated to create 40 gypsum casts that were laser scanned before any fabrication procedures were initiated. A master denture was made using the CAD-CAM process and was then used to create a putty mold for the fabrication of 30 standardized wax festooned dentures, 10 for each of the conventional processing techniques (pack and press, pour, injection). Scan files from 10 casts were sent to Global Dental Science, LLC for fabrication of the CAD-CAM test specimens. After specimens for each of the 4 techniques had been fabricated, they were hydrated for 24 hours and the intaglio surface laser scanned. The scan file of each denture was superimposed on the scan file of the corresponding preprocessing cast using surface matching software. Measurements were made at 60 locations, providing evaluation of fit discrepancies at the following areas: apex of the denture border, 6 mm from the denture border, crest of the ridge, palate, and posterior palatal seal. The use of median and interquartile range was used to assess accuracy and reproducibility. The Levine and Kruskal-Wallis analysis of variance was used to evaluate differences between processing techniques at the 5 specified locations (α=.05). The ranking of results based on median and interquartile range determined that the accuracy and reproducibility of the CAD-CAM technique was more consistently localized around zero at 3 of the 5 locations. Therefore, the CAD-CAM technique showed the best combination of accuracy and reproducibility among the tested fabrication techniques. The pack and press technique was more accurate at 2 of the 5 locations; however, its interquartile range (reproducibility) was the greatest of the 4 tested processing techniques. The pour technique was the most reproducible at 2 of the 5 locations; however, its accuracy was the lowest of the tested techniques. The CAD-CAM fabrication process was the most accurate and reproducible denture fabrication technique when compared with pack and press, pour, and injection denture base processing techniques. Copyright © 2016 Editorial Council for the Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.

The New Weather Radar for America's Space Program in Florida: A Temperature Profile Adaptive Scan Strategy

NASA Technical Reports Server (NTRS)

Carey, L. D.; Petersen, W. A.; Deierling, W.; Roeder, W. P.

2009-01-01

A new weather radar is being acquired for use in support of America s space program at Cape Canaveral Air Force Station, NASA Kennedy Space Center, and Patrick AFB on the east coast of central Florida. This new radar replaces the modified WSR-74C at Patrick AFB that has been in use since 1984. The new radar is a Radtec TDR 43-250, which has Doppler and dual polarization capability. A new fixed scan strategy was designed to best support the space program. The fixed scan strategy represents a complex compromise between many competing factors and relies on climatological heights of various temperatures that are important for improved lightning forecasting and evaluation of Lightning Launch Commit Criteria (LCC), which are the weather rules to avoid lightning strikes to in-flight rockets. The 0 C to -20 C layer is vital since most generation of electric charge occurs within it and so it is critical in evaluating Lightning LCC and in forecasting lightning. These are two of the most important duties of 45 WS. While the fixed scan strategy that covers most of the climatological variation of the 0 C to -20 C levels with high resolution ensures that these critical temperatures are well covered most of the time, it also means that on any particular day the radar is spending precious time scanning at angles covering less important heights. The goal of this project is to develop a user-friendly, Interactive Data Language (IDL) computer program that will automatically generate optimized radar scan strategies that adapt to user input of the temperature profile and other important parameters. By using only the required scan angles output by the temperature profile adaptive scan strategy program, faster update times for volume scans and/or collection of more samples per gate for better data quality is possible, while maintaining high resolution at the critical temperature levels. The temperature profile adaptive technique will also take into account earth curvature and refraction when geo-locating the radar beam (i.e., beam height and arc distance), including non-standard refraction based on the user-input temperature profile. In addition to temperature profile adaptivity, this paper will also summarize the other requirements for this scan strategy program such as detection of low-level boundaries, detection of anvil clouds, reducing the Cone Of Silence, and allowing for times when deep convective clouds will not occur. The adaptive technique will be carefully compared to and benchmarked against the new fixed scan strategy. Specific environmental scenarios in which the adaptive scan strategy is able to optimize and improve coverage and resolution at critical heights, scan time, and/or sample numbers relative to the fixed scan strategy will be presented.

Local dynamic range compensation for scanning electron microscope imaging system.

PubMed

Sim, K S; Huang, Y H

2015-01-01

This is the extended project by introducing the modified dynamic range histogram modification (MDRHM) and is presented in this paper. This technique is used to enhance the scanning electron microscope (SEM) imaging system. By comparing with the conventional histogram modification compensators, this technique utilizes histogram profiling by extending the dynamic range of each tile of an image to the limit of 0-255 range while retains its histogram shape. The proposed technique yields better image compensation compared to conventional methods. © Wiley Periodicals, Inc.

T2-weighted MRI of the upper abdomen: comparison of four fat-suppressed T2-weighted sequences including PROPELLER (BLADE) technique.

PubMed

Bayramoglu, Sibel; Kilickesmez, Ozgür; Cimilli, Tan; Kayhan, Arda; Yirik, Gülseren; Islim, Filiz; Alibek, Sedat

2010-03-01

The aim of this study was to compare four different fat-suppressed T2-weighted sequences with different techniques with regard to image quality and lesion detection in upper abdominal magnetic resonance imaging (MRI) scans. Thirty-two consecutive patients referred for upper abdominal MRI for the evaluation of various suspected pathologies were included in this study. Different T2-weighted sequences (free-breathing navigator-triggered turbo spin-echo [TSE], free-breathing navigator-triggered TSE with restore pulse (RP), breath-hold TSE with RP, and free-breathing navigator-triggered TSE with RP using the periodically rotated overlapping parallel lines with enhanced reconstruction technique [using BLADE, a Siemens implementation of this technique]) were used on all patients. All images were assessed independently by two radiologists. Assessments of motion artifacts; the edge sharpness of the liver, pancreas, and intrahepatic vessels; depictions of the intrahepatic vessels; and overall image quality were performed qualitatively. Quantitative analysis was performed by calculation of the signal-to-noise ratios for liver tissue and gallbladder as well as contrast-to-noise ratios of liver to spleen. Liver and gallbladder signal-to-noise ratios as well as liver to spleen contrast-to-noise ratios were significantly higher (P < .05) for the BLADE technique compared to all other sequences. In qualitative analysis, the severity of motion artifacts was significantly lower with T2-weighted free-breathing navigator-triggered BLADE sequences compared to other sequences (P < .01). The edge sharpness of the liver, pancreas, and intrahepatic vessels; depictions of the intrahepatic vessels; and overall image quality were significantly better with the BLADE sequence (P < .05). The T2-weighted free-breathing navigator-triggered TSE sequence with the BLADE technique is a promising approach for reducing motion artifacts and improving image quality in upper abdominal MRI scans.

Mass spectrometric measurements of atmospheric composition

NASA Technical Reports Server (NTRS)

Hoffman, J. H.

1974-01-01

The development of a magnetic sector field analyzer for continuous sampling and measurement of outer planetary atmospheres is discussed. Special features of the analyzer include a dynamic range of 10 to the minus 7th power, a mass range from 1 to 48 AMU, two ion sensitivities, a special scan time of 35 sec at 14 BPS, and the use of ion counting techniques for analysis.

Patients' preferences when comparing analogue implant impressions using a polyether impression material versus digital impressions (Intraoral Scan) of dental implants.

PubMed

Wismeijer, Daniel; Mans, Ronny; van Genuchten, Michiel; Reijers, Hajo A

2014-10-01

The primary objective of this clinical study was to assess the patients' perception of the difference between an analogue impression approach on the one hand and an intra-oral scan (IO scan) on the other when restoring implants in the non-aesthetic zone. A second objective was to analyse the difference in time needed to perform these two procedures. Thirty consecutive patients who had received 41 implants (Straumann tissue level) in the non-aesthetic zone in an implant-based referral practice setting in the Netherlands. As they were to receive crown and or bridge work on the implants, in one session, the final impressions were taken with both an analogue technique and with an intraoral scan. Patients were also asked if, directly after the treatment was carried out, they would be prepared to fill out a questionnaire on their perception of both techniques. The time involved following these two procedures was also recorded. The preparatory activities of the treatment, the taste of the impression material and the overall preference of the patients were significantly in favour of the IO scan. The bite registration, the scan head and gag reflex positively tended to the IO scan, but none of these effects were significant. The overall time involved with the IO scan was more negatively perceived than the analogue impression. Overall less time was involved when following the analogue impression technique than with the IO scan. The overall preference of the patients in our sample is significantly in favour of the approach using the IO scan. This preference relates mainly to the differences between the compared approaches with respect to taste effects and their preparatory activities. The patients did perceive the duration of IO scan more negatively than the analogue impression approach. © 2013 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

3D volumetric modeling of grapevine biomass using Tripod LiDAR

USGS Publications Warehouse

Keightley, K.E.; Bawden, G.W.

2010-01-01

Tripod mounted laser scanning provides the means to generate high-resolution volumetric measures of vegetation structure and perennial woody tissue for the calculation of standing biomass in agronomic and natural ecosystems. Other than costly destructive harvest methods, no technique exists to rapidly and accurately measure above-ground perennial tissue for woody plants such as Vitis vinifera (common grape vine). Data collected from grapevine trunks and cordons were used to study the accuracy of wood volume derived from laser scanning as compared with volume derived from analog measurements. A set of 10 laser scan datasets were collected for each of 36 vines from which volume was calculated using combinations of two, three, four, six and 10 scans. Likewise, analog volume measurements were made by submerging the vine trunks and cordons in water and capturing the displaced water. A regression analysis examined the relationship between digital and non-digital techniques among the 36 vines and found that the standard error drops rapidly as additional scans are added to the volume calculation process and stabilizes at the four-view geometry with an average Pearson's product moment correlation coefficient of 0.93. Estimates of digital volumes are systematically greater than those of analog volumes and can be explained by the manner in which each technique interacts with the vine tissue. This laser scanning technique yields a highly linear relationship between vine volume and tissue mass revealing a new, rapid and non-destructive method to remotely measure standing biomass. This application shows promise for use in other ecosystems such as orchards and forests. ?? 2010 Elsevier B.V.

Assessing kyphosis with SpineScan: another attempt to reduce our dependence on radiography.

PubMed

Finestone, Aharon S; Marcus, Gil; Anekstein, Yoram; Mirovsky, Yigal; Agar, Gabriel

2013-08-01

Kyphosis management is mainly conservative, with annual examinations to assess angular progression. This includes physical examination and usually long spine X-rays, notorious for ionizing radiation. Several nonradiological instruments have been devised for this, but none have become popular. SpineScan, a programmed digital inclinometer, has been proved effective for screening kyphoscoliosis. The aim of this study was to assess the accuracy of SpineScan in monitoring kyphosis. Prospective, observational, diagnostic accuracy study. Twenty-eight subjects examined for kyphosis, with recent full-length lateral spine X-rays. Each subject was examined by two examiners. The technique involved the subject standing with arms flexed to 90° and then sliding the SpineScan from just below C7 to L2. Maximum X-ray kyphotic Cobb angle was compared with the SpineScan result. The study was institutional review board approved, and all patients signed an informed consent. The mean Cobb angle of the 28 subjects on radiography was 51° ± 15°. The mean SpineScan angle of all trials of all examiners was 54° ± 12°. The difference between the two measurements was significantly different from zero (3.2° ± 9.4°, p<.0001) and not normally distributed. The difference was significantly affected by the Cobb angle, examiner, and interaction between Cobb and examiner (statistical significance for all p<.0001). Ninety-five percent confidence intervals for all examiners ranged between -16° and 22° and for separate examiners between -25° and 32°, far above the 5° preplanned error level. The results demonstrated that there is significant error in monitoring kyphosis with SpineScan. Even for a more modest indication including replacing radiography with SpineScan on alternate visits, the measurement was not accurate enough. Future research is necessary to find a nonradiographic method of kyphosis follow-up, possibly using a digitalized modification of one of the described instruments. Copyright © 2013 Elsevier Inc. All rights reserved.

Infrared Database for Process Support Materials

NASA Technical Reports Server (NTRS)

Bennett, K. E.; Boothe, R. E.; Burns, H. D.

2003-01-01

Process support materials' compatibility with cleaning processes is critical to ensure final hardware cleanliness and that performance requirements are met. Previous discovery of potential contaminants in process materials shows the need for incoming materials testing and establishment of a process materials database. The Contamination Control Team of the Materials, Processes, and Manufacturing (MP&M) Department at Marshall Space Flight Center (MSFC) has initiated the development of such an infrared (IR) database, called the MSFC Process Materials IR database, of the common process support materials used at MSFC. These process support materials include solvents, wiper cloths, gloves, bagging materials, etc. Testing includes evaluation of the potential of gloves, wiper cloths, and other items to transfer contamination to handled articles in the absence of solvent exposure, and the potential for solvent exposure to induce material degradation. This Technical Memorandum (TM) summarizes the initial testing completed through December 2002. It is anticipated that additional testing will be conducted with updates provided in future TMs.Materials were analyzed using two different IR techniques: (1) Dry transference and (2) liquid extraction testing. The first of these techniques utilized the Nicolet Magna 750 IR spectrometer outfitted with a horizontal attenuated total reflectance (HATR) crystal accessory. The region from 650 to 4,000 wave numbers was analyzed, and 50 scans were performed per IR spectrum. A dry transference test was conducted by applying each sample with hand pressure to the HATR crystal to first obtain a spectrum of the parent material. The material was then removed from the HATR crystal and analyzed to determine the presence of any residues. If volatile, liquid samples were examined both prior to and following evaporation.The second technique was to perform an extraction test with each sample in five different solvents.Once the scans were complete for both the dry transference and the extraction tests, the residue from each scan was interpreted.

Spot Scanning Proton Therapy for Malignancies of the Base of Skull: Treatment Planning, Acute Toxicities, and Preliminary Clinical Outcomes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Grosshans, David R., E-mail: dgrossha@mdanderson.org; Zhu, X. Ronald; Melancon, Adam

2014-11-01

Purpose: To describe treatment planning techniques and early clinical outcomes in patients treated with spot scanning proton therapy for chordoma or chondrosarcoma of the skull base. Methods and Materials: From June 2010 through August 2011, 15 patients were treated with spot scanning proton therapy for chordoma (n=10) or chondrosarcoma (n=5) at a single institution. Toxicity was prospectively evaluated and scored weekly and at all follow-up visits according to Common Terminology Criteria for Adverse Events, version 3.0. Treatment planning techniques and dosimetric data were recorded and compared with those of passive scattering plans created with clinically applicable dose constraints. Results: Tenmore » patients were treated with single-field-optimized scanning beam plans and 5 with multifield-optimized intensity modulated proton therapy. All but 2 patients received a simultaneous integrated boost as well. The mean prescribed radiation doses were 69.8 Gy (relative biological effectiveness [RBE]; range, 68-70 Gy [RBE]) for chordoma and 68.4 Gy (RBE) (range, 66-70) for chondrosarcoma. In comparison with passive scattering plans, spot scanning plans demonstrated improved high-dose conformality and sparing of temporal lobes and brainstem. Clinically, the most common acute toxicities included fatigue (grade 2 for 2 patients, grade 1 for 8 patients) and nausea (grade 2 for 2 patients, grade 1 for 6 patients). No toxicities of grades 3 to 5 were recorded. At a median follow-up time of 27 months (range, 13-42 months), 1 patient had experienced local recurrence and a second developed distant metastatic disease. Two patients had magnetic resonance imaging-documented temporal lobe changes, and a third patient developed facial numbness. No other subacute or late effects were recorded. Conclusions: In comparison to passive scattering, treatment plans for spot scanning proton therapy displayed improved high-dose conformality. Clinically, the treatment was well tolerated, and with short-term follow-up, disease control rates and toxicity profiles were favorable.« less

Diagnostic approach to patients with suspected pulmonary embolism: a report from the real world

PubMed Central

Saro, G; Campo, J; Hernandez, M; Anta, M; Olmos, J; Gonzalez-Macias, J; Riancho, J

1999-01-01

This study was carried out to examine the diagnostic approach to patients with suspected pulmonary embolism (PE) in a university hospital. A retrospective case record review of 251 patients with suspected pulmonary embolism was carried out according to a standard protocol, which looked at the utilisation of imaging techniques and compared clinical diagnoses with a standardised diagnosis established according to current recommendations. Isotopic lung scan was the most commonly used technique (73%), followed by leg vein sonography (36%) and contrast venography (31%). Lung arteriography was done in only 7% of patients. Among the 205 patients with a clinical diagnosis of PE, 115 (56%) would be diagnosed as having PE according to the standard criteria, 84 (41%) would be unclassified, and six (3%) would not be regarded as having PE. Among patients who were diagnosed as having PE and received anticoagulant therapy, 32% did not have the diagnosis confirmed by an imaging technique. Most of these had a non-diagnostic lung scan which, despite evidence to the contrary, seemed to be interpreted as confirmation of PE. We conclude that clinicians do not seem to follow current recommendations when approaching patients with suspected PE. In particular, there is an over-reliance on lung scans, and the significance of non-diagnostic scans was often misinterpreted. Arteriography was underused. These results emphasise the need to take measures to implement practice guidelines and to explore the usefulness of newer non-invasive techniques.


Keywords: pulmonary embolism; diagnosis; lung scan; imaging techniques; audit PMID:10533633

Effect of topogram-tube angle combination on CT radiation dose reduction

NASA Astrophysics Data System (ADS)

Shim, J.; Yoon, M.

2017-09-01

This study assessed the ability of various types of topograms, when used with an automatic tube current modulation (ATCM) technique, to reduce radiation dose from computed tomography (CT) scans. Three types of topograms were used with the ATCM technique: (i) anteroposterior (AP) topograms alone, (ii) AP topograms followed by lateral topograms, and (iii) lateral topograms followed by AP topograms. Various regions (chest, abdomen and whole-body) of a humanoid phantom were scanned at several tube voltages (80, 100 and 120 kVp) with the selected topograms. Although the CT dose depended on the order of topograms, the CT dose with respect to patient positioning depended on the number of topograms performed. The magnitude of the difference in CT dose between number and order of topograms was greater for the scans of the abdomen than the chest. These results suggest that, for the Siemens SOMATOM Definition AS CT scanner, choosing the right combination of CT scan conditions with the ATCM technique can minimize radiation dose to a patient.

Assessment of virtual towers performed with scanning wind lidars and Ka-band radars during the XPIA experiment

DOE PAGES

Debnath, Mithu; Iungo, Giacomo Valerio; Brewer, W. Alan; ...

2017-03-29

During the eXperimental Planetary boundary layer Instrumentation Assessment (XPIA) campaign, which was carried out at the Boulder Atmospheric Observatory (BAO) in spring 2015, multiple-Doppler scanning strategies were carried out with scanning wind lidars and Ka-band radars. Specifically, step–stare measurements were collected simultaneously with three scanning Doppler lidars, while two scanning Ka-band radars carried out simultaneous range height indicator (RHI) scans. The XPIA experiment provided the unique opportunity to compare directly virtual-tower measurements performed simultaneously with Ka-band radars and Doppler wind lidars. Furthermore, multiple-Doppler measurements were assessed against sonic anemometer data acquired from the meteorological tower (met-tower) present at the BAOmore » site and a lidar wind profiler. As a result, this survey shows that – despite the different technologies, measurement volumes and sampling periods used for the lidar and radar measurements – a very good accuracy is achieved for both remote-sensing techniques for probing horizontal wind speed and wind direction with the virtual-tower scanning technique.« less

A Practical Guide to Environmental Scanning: Approaches, Sources, and Selected Techniques.

ERIC Educational Resources Information Center

Clagett, Craig A.

1989-01-01

A guide to environmental scanning looks at its rationale and relationship to strategic planning, and outlines three administrative approaches: establishment of a committee, sponsoring a scanning conference or event, and assigning the task to the institutional research or planning office. (MSE)

Environmental Scanning Practices for Rural Colleges.

ERIC Educational Resources Information Center

Friedel, Janice Nahra; Lapin, Joel D.

1995-01-01

Discusses the importance of environmental scanning in the planning efforts of rural community colleges. Reviews basic techniques and terminology and suggests sources of data. Argues that environmental scanning allows rural colleges to inexpensively forecast change, identify implications for the organization, and plan preferred responses to shape…

DOE Office of Scientific and Technical Information (OSTI.GOV)

Debnath, Mithu; Iungo, Giacomo Valerio; Brewer, W. Alan

During the eXperimental Planetary boundary layer Instrumentation Assessment (XPIA) campaign, which was carried out at the Boulder Atmospheric Observatory (BAO) in spring 2015, multiple-Doppler scanning strategies were carried out with scanning wind lidars and Ka-band radars. Specifically, step–stare measurements were collected simultaneously with three scanning Doppler lidars, while two scanning Ka-band radars carried out simultaneous range height indicator (RHI) scans. The XPIA experiment provided the unique opportunity to compare directly virtual-tower measurements performed simultaneously with Ka-band radars and Doppler wind lidars. Furthermore, multiple-Doppler measurements were assessed against sonic anemometer data acquired from the meteorological tower (met-tower) present at the BAOmore » site and a lidar wind profiler. As a result, this survey shows that – despite the different technologies, measurement volumes and sampling periods used for the lidar and radar measurements – a very good accuracy is achieved for both remote-sensing techniques for probing horizontal wind speed and wind direction with the virtual-tower scanning technique.« less

Three-Dimensional Digital Documentation of Heritage Sites Using Terrestrial Laser Scanning and Unmanned Aerial Vehicle Photogrammetry

NASA Astrophysics Data System (ADS)

Jo, Y. H.; Kim, J. Y.

2017-08-01

Three-dimensional digital documentation is an important technique for the maintenance and monitoring of cultural heritage sites. This study focuses on the three-dimensional digital documentation of the Magoksa Temple, Republic of Korea, using a combination of terrestrial laser scanning and unmanned aerial vehicle (UAV) photogrammetry. Terrestrial laser scanning mostly acquired the vertical geometry of the buildings. In addition, the digital orthoimage produced by UAV photogrammetry had higher horizontal data acquisition rate than that produced by terrestrial laser scanning. Thus, the scanning and UAV photogrammetry were merged by matching 20 corresponding points and an absolute coordinate system was established using seven ground control points. The final, complete threedimensional shape had perfect horizontal and vertical geometries. This study demonstrates the potential of integrating terrestrial laser scanning and UAV photogrammetry for three-dimensional digital documentation. This new technique is expected to contribute to the three-dimensional digital documentation and spatial analysis of cultural heritage sites.

Strontium-85 Scanning of Suspected Bone Disease

PubMed Central

Parsons, Victor; Williams, Margery; Hill, David; Frost, Pamela; Lapham, Avril

1969-01-01

Strontium-85 scanning of suspected bone lesions in 81 patients has added to the criteria for the diagnosis of malignant and other lesions of bone. Of 46 patients with a previous history of malignant disease and skeletal symptoms negative radiological findings were recorded in 19, but nine of these had positive scans, eight of which when followed up over periods of up to four years proved to be metastatic. A similar prevalence of positive scans occurred in patients without a previous history of malignancy. Because of the anatomical localization of lesions made possible by this technique a tissue diagnosis was made in six patients, while fields of radiotherapy were altered in another seven. This technique can improve the management of patients with suspected bone disease. PMID:5761888

HelioScan: a software framework for controlling in vivo microscopy setups with high hardware flexibility, functional diversity and extendibility.

PubMed

Langer, Dominik; van 't Hoff, Marcel; Keller, Andreas J; Nagaraja, Chetan; Pfäffli, Oliver A; Göldi, Maurice; Kasper, Hansjörg; Helmchen, Fritjof

2013-04-30

Intravital microscopy such as in vivo imaging of brain dynamics is often performed with custom-built microscope setups controlled by custom-written software to meet specific requirements. Continuous technological advancement in the field has created a need for new control software that is flexible enough to support the biological researcher with innovative imaging techniques and provide the developer with a solid platform for quickly and easily implementing new extensions. Here, we introduce HelioScan, a software package written in LabVIEW, as a platform serving this dual role. HelioScan is designed as a collection of components that can be flexibly assembled into microscope control software tailored to the particular hardware and functionality requirements. Moreover, HelioScan provides a software framework, within which new functionality can be implemented in a quick and structured manner. A specific HelioScan application assembles at run-time from individual software components, based on user-definable configuration files. Due to its component-based architecture, HelioScan can exploit synergies of multiple developers working in parallel on different components in a community effort. We exemplify the capabilities and versatility of HelioScan by demonstrating several in vivo brain imaging modes, including camera-based intrinsic optical signal imaging for functional mapping of cortical areas, standard two-photon laser-scanning microscopy using galvanometric mirrors, and high-speed in vivo two-photon calcium imaging using either acousto-optic deflectors or a resonant scanner. We recommend HelioScan as a convenient software framework for the in vivo imaging community. Copyright © 2013 Elsevier B.V. All rights reserved.

Scalp imaging techniques

NASA Astrophysics Data System (ADS)

Otberg, Nina; Shapiro, Jerry; Lui, Harvey; Wu, Wen-Yu; Alzolibani, Abdullateef; Kang, Hoon; Richter, Heike; Lademann, Jürgen

2017-05-01

Scalp imaging techniques are necessary tools for the trichological practice and for visualization of permeation, penetration and absorption processes into and through the scalp and for the research on drug delivery and toxicology. The present letter reviews different scalp imaging techniques and discusses their utility. Moreover, two different studies on scalp imaging techniques are presented in this letter: (1) scalp imaging with phototrichograms in combination with laser scanning microscopy, and (2) follicular measurements with cyanoacrylate surface replicas and light microscopy in combination with laser scanning microscopy. The experiments compare different methods for the determination of hair density on the scalp and different follicular measures. An average terminal hair density of 132 hairs cm-2 was found in 6 Caucasian volunteers and 135 hairs cm-2 in 6 Asian volunteers. The area of the follicular orifices accounts to 16.3% of the skin surface on average measured with laser scanning microscopy images. The potential volume of the follicular infundibulum was calculated based on the laser scanning measurements and is found to be 4.63 mm3 per cm2 skin on average. The experiments show that hair follicles are quantitatively relevant pathways and potential reservoirs for topically applied drugs and cosmetics.

Characterization of some biological specimens using TEM and SEM

NASA Astrophysics Data System (ADS)

Ghosh, Nabarun; Smith, Don W.

2009-05-01

The advent of novel techniques using the Transmission and Scanning Electron Microscopes improved observation on various biological specimens to characterize them. We studied some biological specimens using Transmission and Scanning Electron Microscopes. We followed negative staining technique with Phosphotungstic acid using bacterial culture of Bacillus subtilis. Negative staining is very convenient technique to view the structural morphology of different samples including bacteria, phage viruses and filaments in a cell. We could observe the bacterial cell wall and flagellum very well when trapped the negative stained biofilm from bacterial culture on a TEM grid. We cut ultra thin sections from the fixed root tips of Pisum sativum (Garden pea). Root tips were pre fixed with osmium tetroxide and post fixed with uranium acetate and placed in the BEEM capsule for block making. The ultrathin sections on the grid under TEM showed the granular chromatin in the nucleus. The protein bodies and large vacuoles with the storage materials were conspicuous. We followed fixation, critical point drying and sputter coating with gold to view the tissues with SEM after placing on stubs. SEM view of the leaf surface of a dangerous weed Tragia hispida showed the surface trichomes. These trichomes when break on touching releases poisonous content causing skin irritation. The cultured tissue from in vitro culture of Albizia lebbeck, a tree revealed the regenerative structures including leaf buds and stomata on the tissue surface. SEM and TEM allow investigating the minute details characteristic morphological features that can be used for classroom teaching.

Morphometricity as a measure of the neuroanatomical signature of a trait.

PubMed

Sabuncu, Mert R; Ge, Tian; Holmes, Avram J; Smoller, Jordan W; Buckner, Randy L; Fischl, Bruce

2016-09-27

Complex physiological and behavioral traits, including neurological and psychiatric disorders, often associate with distributed anatomical variation. This paper introduces a global metric, called morphometricity, as a measure of the anatomical signature of different traits. Morphometricity is defined as the proportion of phenotypic variation that can be explained by macroscopic brain morphology. We estimate morphometricity via a linear mixed-effects model that uses an anatomical similarity matrix computed based on measurements derived from structural brain MRI scans. We examined over 3,800 unique MRI scans from nine large-scale studies to estimate the morphometricity of a range of phenotypes, including clinical diagnoses such as Alzheimer's disease, and nonclinical traits such as measures of cognition. Our results demonstrate that morphometricity can provide novel insights about the neuroanatomical correlates of a diverse set of traits, revealing associations that might not be detectable through traditional statistical techniques.

Morphometricity as a measure of the neuroanatomical signature of a trait

PubMed Central

Sabuncu, Mert R.; Ge, Tian; Holmes, Avram J.; Smoller, Jordan W.; Buckner, Randy L.; Fischl, Bruce

2016-01-01

Complex physiological and behavioral traits, including neurological and psychiatric disorders, often associate with distributed anatomical variation. This paper introduces a global metric, called morphometricity, as a measure of the anatomical signature of different traits. Morphometricity is defined as the proportion of phenotypic variation that can be explained by macroscopic brain morphology. We estimate morphometricity via a linear mixed-effects model that uses an anatomical similarity matrix computed based on measurements derived from structural brain MRI scans. We examined over 3,800 unique MRI scans from nine large-scale studies to estimate the morphometricity of a range of phenotypes, including clinical diagnoses such as Alzheimer’s disease, and nonclinical traits such as measures of cognition. Our results demonstrate that morphometricity can provide novel insights about the neuroanatomical correlates of a diverse set of traits, revealing associations that might not be detectable through traditional statistical techniques. PMID:27613854

Automated method and system for the alignment and correlation of images from two different modalities

DOEpatents

Giger, Maryellen L.; Chen, Chin-Tu; Armato, Samuel; Doi, Kunio

1999-10-26

A method and system for the computerized registration of radionuclide images with radiographic images, including generating image data from radiographic and radionuclide images of the thorax. Techniques include contouring the lung regions in each type of chest image, scaling and registration of the contours based on location of lung apices, and superimposition after appropriate shifting of the images. Specific applications are given for the automated registration of radionuclide lungs scans with chest radiographs. The method in the example given yields a system that spatially registers and correlates digitized chest radiographs with V/Q scans in order to correlate V/Q functional information with the greater structural detail of chest radiographs. Final output could be the computer-determined contours from each type of image superimposed on any of the original images, or superimposition of the radionuclide image data, which contains high activity, onto the radiographic chest image.

Flow-gated radial phase-contrast imaging in the presence of weak flow.

PubMed

Peng, Hsu-Hsia; Huang, Teng-Yi; Wang, Fu-Nien; Chung, Hsiao-Wen

2013-01-01

To implement a flow-gating method to acquire phase-contrast (PC) images of carotid arteries without use of an electrocardiography (ECG) signal to synchronize the acquisition of imaging data with pulsatile arterial flow. The flow-gating method was realized through radial scanning and sophisticated post-processing methods including downsampling, complex difference, and correlation analysis to improve the evaluation of flow-gating times in radial phase-contrast scans. Quantitatively comparable results (R = 0.92-0.96, n = 9) of flow-related parameters, including mean velocity, mean flow rate, and flow volume, with conventional ECG-gated imaging demonstrated that the proposed method is highly feasible. The radial flow-gating PC imaging method is applicable in carotid arteries. The proposed flow-gating method can potentially avoid the setting up of ECG-related equipment for brain imaging. This technique has potential use in patients with arrhythmia or weak ECG signals.

International Symposium on Remote Sensing of Environment, 9th, University of Michigan, Ann Arbor, Mich., April 15-19, 1974, Proceedings. Volumes 1, 2 & 3

NASA Technical Reports Server (NTRS)

1974-01-01

The present work gathers together numerous papers describing the use of remote sensing technology for mapping, monitoring, and management of earth resources and man's environment. Studies using various types of sensing equipment are described, including multispectral scanners, radar imagery, spectrometers, lidar, and aerial photography, and both manual and computer-aided data processing techniques are described. Some of the topics covered include: estimation of population density in Tokyo districts from ERTS-1 data, a clustering algorithm for unsupervised crop classification, passive microwave sensing of moist soils, interactive computer processing for land use planning, the use of remote sensing to delineate floodplains, moisture detection from Skylab, scanning thermal plumes, electrically scanning microwave radiometers, oil slick detection by X-band synthetic aperture radar, and the use of space photos for search of oil and gas fields. Individual items are announced in this issue.

Nanoscale elasticity mappings of micro-constituents of abalone shell by band excitation-contact resonance force microscopy

NASA Astrophysics Data System (ADS)

Li, Tao; Zeng, Kaiyang

2014-01-01

The macroscopic mechanical properties of the abalone shell have been studied extensively in the literature, but the in situ nanoscale elasticity of various micro-constituents in the shell have not been characterized and reported yet. In this study, the nanoscale elasticity mappings including different micro-constituents in abalone shell were observed by using the Contact Resonance Force Microscopy (CR-FM) technique. CR-FM is one of the advanced scanning probe microscopy techniques that is able to quantify the local elastic moduli of various materials in a non-destructive manner. Instead of an average value, an elasticity mapping that reveals the nanoscale variations of elastic moduli with location can be extracted and correlated with the topography of the structure. Therefore in this study, by adopting the CR-FM technique that is incorporated with the band excitation technique, the elasticity variations of the abalone shell caused by different micro-constituents and crystal orientations are reported, and the elasticity values of the aragonite and calcite nanograins are quantified.The macroscopic mechanical properties of the abalone shell have been studied extensively in the literature, but the in situ nanoscale elasticity of various micro-constituents in the shell have not been characterized and reported yet. In this study, the nanoscale elasticity mappings including different micro-constituents in abalone shell were observed by using the Contact Resonance Force Microscopy (CR-FM) technique. CR-FM is one of the advanced scanning probe microscopy techniques that is able to quantify the local elastic moduli of various materials in a non-destructive manner. Instead of an average value, an elasticity mapping that reveals the nanoscale variations of elastic moduli with location can be extracted and correlated with the topography of the structure. Therefore in this study, by adopting the CR-FM technique that is incorporated with the band excitation technique, the elasticity variations of the abalone shell caused by different micro-constituents and crystal orientations are reported, and the elasticity values of the aragonite and calcite nanograins are quantified. Electronic supplementary information (ESI) available. See DOI: 10.1039/c3nr05292c

Relative plan robustness of step-and-shoot vs rotational intensity–modulated radiotherapy on repeat computed tomographic simulation for weight loss in head and neck cancer

DOE Office of Scientific and Technical Information (OSTI.GOV)

Thomson, David J.; The University of Manchester, Manchester Academic Health Science Centre, Institute of Cancer Sciences, Manchester; Beasley, William J.

Introduction: Interfractional anatomical alterations may have a differential effect on the dose delivered by step-and-shoot intensity-modulated radiotherapy (IMRT) and volumetric-modulated arc therapy (VMAT). The increased degrees of freedom afforded by rotational delivery may increase plan robustness (measured by change in target volume coverage and doses to organs at risk [OARs]). However, this has not been evaluated for head and neck cancer. Materials and methods: A total of 10 patients who required repeat computed tomography (CT) simulation and replanning during head and neck IMRT were included. Step-and-shoot IMRT and VMAT plans were generated from the original planning scan. The initial andmore » second CT simulation scans were fused and targets/OAR contours transferred, reviewed, and modified. The plans were applied to the second CT scan and doses recalculated without repeat optimization. Differences between step-and-shoot IMRT and VMAT for change in target volume coverage and doses to OARs between first and second CT scans were compared by Wilcoxon signed rank test. Results: There were clinically relevant dosimetric changes between the first and the second CT scans for both the techniques (reduction in mean D{sub 95%} for PTV2 and PTV3, D{sub min} for CTV2 and CTV3, and increased mean doses to the parotid glands). However, there were no significant differences between step-and-shoot IMRT and VMAT for change in any target coverage parameter (including D{sub 95%} for PTV2 and PTV3 and D{sub min} for CTV2 and CTV3) or dose to any OARs (including parotid glands) between the first and the second CT scans. Conclusions: For patients with head and neck cancer who required replanning mainly due to weight loss, there were no significant differences in plan robustness between step-and-shoot IMRT and VMAT. This information is useful with increased clinical adoption of VMAT.« less

B-scan technique for localization and characterization of fatigue cracks around fastener holes in multi-layered structures

NASA Astrophysics Data System (ADS)

Hopkins, Deborah; Datuin, Marvin; Aldrin, John; Warchol, Mark; Warchol, Lyudmila; Forsyth, David

2018-04-01

The work presented here aims to develop and transition angled-beam shear-wave inspection techniques for crack localization at fastener sites in multi-layer aircraft structures. This requires moving beyond detection to achieve reliable crack location and size, thereby providing invaluable information for maintenance actions and service-life management. The technique presented is based on imaging cracks in "True" B-scans (depth view projected in the sheets along the beam path). The crack traces that contribute to localization in the True B-scans depend on small, diffracted signals from the crack edges and tips that are visible in simulations and experimental data acquired with sufficient gain. The most recent work shows that cracks rotated toward and away from the central ultrasonic beam also yield crack traces in True B-scans that allow localization in simulations, even for large obtuse angles where experimental and simulation results show very small or no indications in the C-scans. Similarly, for two sheets joined by sealant, simulations show that cracks in the second sheet can be located in True B-scans for all locations studied: cracks that intersect the front or back wall of the second sheet, as well as relatively small mid-bore cracks. These results are consistent with previous model verification and sensitivity studies that demonstrate crack localization in True B-scans for a single sheet and cracks perpendicular to the ultrasonic beam.

Slit scan radiographic system for intermediate size rocket motors

NASA Astrophysics Data System (ADS)

Bernardi, Richard T.; Waters, David D.

1992-12-01

The development of slit-scan radiography capability for the NASA Advanced Computed Tomography Inspection System (ACTIS) computed tomography (CT) scanner at MSFC is discussed. This allows for tangential case interface (bondline) inspection at 2 MeV of intermediate-size rocket motors like the Hawk. Motorized mounting fixture hardware was designed, fabricated, installed, and tested on ACTIS. The ACTIS linear array of x-ray detectors was aligned parallel to the tangent line of a horizontal Hawk motor case. A 5 mm thick x-ray fan beam was used. Slit-scan images were produced with continuous rotation of a horizontal Hawk motor. Image features along Hawk motor case interfaces were indicated. A motorized exit cone fixture for ACTIS slit-scan inspection was also provided. The results of this SBIR have shown that slit scanning is an alternative imaging technique for case interface inspection. More data is required to qualify the technique for bondline inspection.

Evaluation of the three-dimensional accuracy of implant impression techniques in two simulated clinical conditions by optical scanning.

PubMed

Sabouhi, Mahmoud; Bajoghli, Farshad; Abolhasani, Majid

2015-01-01

The success of an implant-supported prosthesis is dependent on the passive fit of its framework fabricated on a precise cast. The aim of this in vitro study was to digitally compare the three-dimensional accuracy of implant impression techniques in partially and completely edentulous conditions. The master model simulated two clinical conditions. The first condition was a partially edentulous mandibular arch with an anterior edentulous space (D condition). Two implant analogs were inserted in bilateral canine sites. After elimination of the teeth, the model was converted to a completely edentulous condition (E condition). Three different impression techniques were performed (open splinted [OS], open unsplinted [OU], closed [C]) for each condition. Six groups of casts (DOS, DOU, DC, EOS, EOU, EC) (n = 8), totaling 48 casts, were made. Two scan bodies were secured onto the master edentulous model and onto each test cast and digitized by an optical scanning system. The related scans were superimposed, and the mean discrepancy for each cast was determined. The statistical analysis showed no significant difference in the accuracy of casts as a function of model status (P = .78, analysis of variance [ANOVA] test), impression technique (P = .57, ANOVA test), or as the combination of both (P = .29, ANOVA test). The distribution of data was normal (Kolmogorov-Smirnov test). Model status (dentate or edentulous) and impression technique did not influence the precision of the casts. There is no difference among any of the impression techniques in either simulated clinical condition.

Evaluation of the interaction of coumarins with biomembrane models studied by differential scanning calorimetry and Langmuir-Blodgett techniques.

PubMed

Sarpietro, Maria Grazia; Giuffrida, Maria Chiara; Ottimo, Sara; Micieli, Dorotea; Castelli, Francesco

2011-04-25

Three coumarins, scopoletin (1), esculetin (2), and esculin (3), were investigated by differential scanning calorimetry and Langmuir-Blodgett techniques to gain information about the interaction of these compounds with cellular membranes. Phospholipids assembled as multilamellar vesicles or monolayers (at the air-water interface) were used as biomembrane models. Differential scanning calorimetry was employed to study the interaction of these coumarins with multilamellar vesicles and to evaluate their absorption by multilamellar vesicles. These experiments indicated that 1-3 interact in this manner to different extents. The Langmuir-Blodgett technique was used to study the effect of these coumarins on the organization of phospholipids assembled as a monolayer. The data obtained were in agreement with those obtained in the calorimetric experiments.

3D Modeling Techniques for Print and Digital Media

NASA Astrophysics Data System (ADS)

Stephens, Megan Ashley

In developing my thesis, I looked to gain skills using ZBrush to create 3D models, 3D scanning, and 3D printing. The models created compared the hearts of several vertebrates and were intended for students attending Comparative Vertebrate Anatomy. I used several resources to create a model of the human heart and was able to work from life while creating heart models from other vertebrates. I successfully learned ZBrush and 3D scanning, and successfully printed 3D heart models. ZBrush allowed me to create several intricate models for use in both animation and print media. The 3D scanning technique did not fit my needs for the project, but may be of use for later projects. I was able to 3D print using two different techniques as well.

Improvement to the scanning electron microscope image adaptive Canny optimization colorization by pseudo-mapping.

PubMed

Lo, T Y; Sim, K S; Tso, C P; Nia, M E

2014-01-01

An improvement to the previously proposed adaptive Canny optimization technique for scanning electron microscope image colorization is reported. The additional feature, called pseudo-mapping technique, is that the grayscale markings are temporarily mapped to a set of pre-defined pseudo-color map as a mean to instill color information for grayscale colors in chrominance channels. This allows the presence of grayscale markings to be identified; hence optimization colorization of grayscale colors is made possible. This additional feature enhances the flexibility of scanning electron microscope image colorization by providing wider range of possible color enhancement. Furthermore, the nature of this technique also allows users to adjust the luminance intensities of selected region from the original image within certain extent. © 2014 Wiley Periodicals, Inc.

Pathways to the Future: Linking Environmental Scanning to Strategic Management.

ERIC Educational Resources Information Center

Mecca, Thomas V.; Morrison, James L.

1988-01-01

Describes an ED QUEST (Quick Environmental Scanning Technique) workshop demonstrating the links between an environmental scanning/forecasting process and formulation of institutional strategy. Explains ED QUEST's use in identifying and analyzing critical trends and events, and identifying the nature of the organization; developing alternative…

Environmental Scanning Is Vital to Strategic Planning.

ERIC Educational Resources Information Center

Poole, Molly Linda

1991-01-01

Educators involved in strategic planning can use environmental scanning techniques to anticipate social, economic, political, and technological changes that will affect their schools. Compared to more traditional data gathering, environmental scanning is wider in scope and more concerned with anticipating the future and studying the interaction of…

Comparison Between Laser Scanning and Automated 3d Modelling Techniques to Reconstruct Complex and Extensive Cultural Heritage Areas

NASA Astrophysics Data System (ADS)

Fassi, F.; Fregonese, L.; Ackermann, S.; De Troia, V.

2013-02-01

In Cultural Heritage field, the necessity to survey objects in a fast manner, with the ability to repeat the measurements several times for deformation or degradation monitoring purposes, is increasing. In this paper, two significant cases, an architectonical one and an archaeological one, are presented. Due to different reasons and emergency situations, the finding of the optimal solution to enable quick and well-timed survey for a complete digital reconstruction of the object is required. In both cases, two survey methods have been tested and used: a laser scanning approach that allows to obtain high-resolution and complete scans within a short time and a photogrammetric one that allows the three-dimensional reconstruction of the object from images. In the last months, several methodologies, including free or low cost techniques, have arisen. These kinds of software allow the fully automatically three-dimensional reconstruction of objects from images, giving back a dense point cloud and, in some case, a surfaced mesh model. In this paper some comparisons between the two methodologies above mentioned are presented, using the example of some real cases of study. The surveys have been performed by employing both photogrammetry and laser scanner techniques. The methodological operational choices, depending on the required goal, the difficulties encountered during the survey with these methods, the execution time (that is the key parameter), and finally the obtained results, are fully described and examinated. On the final 3D model, an analytical comparison has been made, to analyse the differences, the tolerances, the possibility of accuracy improvement and the future developments.

Measurements of neutron dose equivalent for a proton therapy center using uniform scanning proton beams

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zheng Yuanshui; Liu Yaxi; Zeidan, Omar

Purpose: Neutron exposure is of concern in proton therapy, and varies with beam delivery technique, nozzle design, and treatment conditions. Uniform scanning is an emerging treatment technique in proton therapy, but neutron exposure for this technique has not been fully studied. The purpose of this study is to investigate the neutron dose equivalent per therapeutic dose, H/D, under various treatment conditions for uniform scanning beams employed at our proton therapy center. Methods: Using a wide energy neutron dose equivalent detector (SWENDI-II, ThermoScientific, MA), the authors measured H/D at 50 cm lateral to the isocenter as a function of proton range,more » modulation width, beam scanning area, collimated field size, and snout position. They also studied the influence of other factors on neutron dose equivalent, such as aperture material, the presence of a compensator, and measurement locations. They measured H/D for various treatment sites using patient-specific treatment parameters. Finally, they compared H/D values for various beam delivery techniques at various facilities under similar conditions. Results: H/D increased rapidly with proton range and modulation width, varying from about 0.2 mSv/Gy for a 5 cm range and 2 cm modulation width beam to 2.7 mSv/Gy for a 30 cm range and 30 cm modulation width beam when 18 Multiplication-Sign 18 cm{sup 2} uniform scanning beams were used. H/D increased linearly with the beam scanning area, and decreased slowly with aperture size and snout retraction. The presence of a compensator reduced the H/D slightly compared with that without a compensator present. Aperture material and compensator material also have an influence on neutron dose equivalent, but the influence is relatively small. H/D varied from about 0.5 mSv/Gy for a brain tumor treatment to about 3.5 mSv/Gy for a pelvic case. Conclusions: This study presents H/D as a function of various treatment parameters for uniform scanning proton beams. For similar treatment conditions, the H/D value per uncollimated beam size for uniform scanning beams was slightly lower than that from a passive scattering beam and higher than that from a pencil beam scanning beam, within a factor of 2. Minimizing beam scanning area could effectively reduce neutron dose equivalent for uniform scanning beams, down to the level close to pencil beam scanning.« less

Signal-to-noise ratio estimation on SEM images using cubic spline interpolation with Savitzky-Golay smoothing.

PubMed

Sim, K S; Kiani, M A; Nia, M E; Tso, C P

2014-01-01

A new technique based on cubic spline interpolation with Savitzky-Golay noise reduction filtering is designed to estimate signal-to-noise ratio of scanning electron microscopy (SEM) images. This approach is found to present better result when compared with two existing techniques: nearest neighbourhood and first-order interpolation. When applied to evaluate the quality of SEM images, noise can be eliminated efficiently with optimal choice of scan rate from real-time SEM images, without generating corruption or increasing scanning time. © 2013 The Authors Journal of Microscopy © 2013 Royal Microscopical Society.

Nonlinear optical characterization of ZnS thin film synthesized by chemical spray pyrolysis method

NASA Astrophysics Data System (ADS)

G, Sreeja V.; V, Sabitha P.; Anila, E. I.; R, Reshmi; John, Manu Punnan; Radhakrishnan, P.

2014-10-01

ZnS thin film was prepared by Chemical Spray Pyrolysis (CSP) method. The sample was characterized by X-ray diffraction method and Z scan technique. XRD pattern showed that ZnS thin film has hexagonal structure with an average size of about 5.6nm. The nonlinear optical properties of ZnS thin film was studied by open aperture Z-Scan technique using Q-switched Nd-Yag Laser at 532nm. The Z-scan plot showed that the investigated ZnS thin film has saturable absorption behavior. The nonlinear absorption coefficient and saturation intensity were also estimated.

Pump-probe optical microscopy for imaging nonfluorescent chromophores.

PubMed

Wei, Lu; Min, Wei

2012-06-01

Many chromophores absorb light intensely but have undetectable fluorescence. Hence microscopy techniques other than fluorescence are highly desirable for imaging these chromophores inside live cells, tissues, and organisms. The recently developed pump-probe optical microscopy techniques provide fluorescence-free contrast mechanisms by employing several fundamental light-molecule interactions including excited state absorption, stimulated emission, ground state depletion, and the photothermal effect. By using the pump pulse to excite molecules and the subsequent probe pulse to interrogate the created transient states on a laser scanning microscope, pump-probe microscopy offers imaging capability with high sensitivity and specificity toward nonfluorescent chromophores. Single-molecule sensitivity has even been demonstrated. Here we review and summarize the underlying principles of this emerging class of molecular imaging techniques.

International Seminar on Laser and Opto-Electronic Technology in Industry: State-of-the-Art Review, Xiamen, People's Republic of China, June 25-28, 1986, Proceedings

NASA Astrophysics Data System (ADS)

Ke, Jingtang; Pryputniewicz, Ryszard J.

Various papers on the state of the art in laser and optoelectronic technology in industry are presented. Individual topics addressed include: wavelength compensation for holographic optical element, optoelectronic techniques for measurement and inspection, new optical measurement methods in Western Europe, applications of coherent optics at ISL, imaging techniques for gas turbine development, the Rolls-Royce experience with industrial holography, panoramic holocamera for tube and borehole inspection, optical characterization of electronic materials, optical strain measurement of rotating components, quantitative interpretation of holograms and specklegrams, laser speckle technique for hydraulic structural model test, study of holospeckle interferometry, common path shearing fringe scanning interferometer, and laser interferometry applied to nondestructive testing of tires.

Characterization of the Roman curse tablet

NASA Astrophysics Data System (ADS)

Liu, Wen; Zhang, Boyang; Fu, Lin

2017-08-01

The Roman curse tablet, produced in ancient Rome period, is a metal plate that inscribed with curses. In this research, several techniques were used to find out the physical structure and chemical composition of the Roman curse tablet, and testified the hypothesis that whether the tablet is made of pure lead or lead alloy. A sample of Roman Curse Tablet from the Johns Hopkins Archaeological Museum was analyzed using several different characterization techniques to determine the physical structure and chemical composition. The characterization techniques used were including optical microscopy, scanning electron microscopy (SEM), atomic force microscopy (AFM), and differential scanning calorimetry (DSC). Because of the small sample size, X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and X-ray fluorescence (XRF) cannot test the sample. Results from optical microscopy and SEM, enlarged images of the sample surface were studied. The result revealed that the sample surface has a rough, non-uniform, and grainy surface. AFM provides three-dimensional topography of the sample surface, studying the sample surface in atomic level. DSC studies the thermal property, which is most likely a lead-alloy, not a pure lead. However, none of these tests indicated anything about the chemical composition. Future work will be required due to the lack of measures finding out its chemical composition. Therefore, from these characterization techniques above, the Roman curse tablet sample is consisted of lead alloy, not pure lead.

Hemispherical Scanning Imaging DOAS: Resolving nitrogen dioxide in the urban environment

NASA Astrophysics Data System (ADS)

Leigh, R. J.; Graves, R. R.; Lawrence, J.; Faloon, K.; Monks, P. S.

2012-12-01

Imaging DOAS techniques have been used for nitrogen dioxide and sulfer dioxide for a number of years. This presentation describes a novel system which images concentrations of nitrogen dioxide by scanning an imaging spectrometer 360 degrees azimuthally, covering a region from 5 degrees below the horizon, to the zenith. The instrument has been built at the University of Leicester (UK), on optical designs by Surrey Satellite Technologies Ltd, and incorporates an Offner relay with Schwarzchild fore-optics, in a rotating mount. The spectrometer offers high fidelity spectroscopic retrievals of nitrogen dioxide as a result of a reliable Gaussian line shape, zero smile and low chromatic aberration. The full hemispherical scanning provides complete coverage of nitrogen dioxide concentrations above approximately 5 ppbv in urban environments. Through the use of multiple instruments, the three-dimensional structure of nitrogen dioxide can be sampled and tomographically reconstructed, providing valuable information on nitrogen dioxide emissions and downwind exposure, in addition to new understanding of boundary layer dynamics through the use of nitrogen dioxide as a tracer. Furthermore, certain aerosol information can be retrieved through absolute intensity measurements in each azimuthal direction supplemented by traditional techniques of O4 spectroscopy. Such measurements provide a new tool for boundary layer measurement and monitoring at a time when air quality implications on human health and climate are under significant scrutiny. This presentation will describe the instrument and tomographic potential of this technique. First measurements were taken as part of the international PEGASOS campaign in Bologna, Italy. Results from these measurements will be shown, including imaging of enhanced NO2 in the Bologna urban boundary layer during a severe thunderstorm. A Hemispherical Scanning Imaging DOAS instrument operating in Bologna, Italy in June 2012. Visible in the background over Bologna is an instrumented Zepplin measuring NO2 and ozone among other species. A hemispherical panorama of nitrogen dioxide concentrations, as measured by the HSI-DOAS instrument in Bologna.

Accuracy of impression scanning compared with stone casts of implant impressions.

PubMed

Matta, Ragai Edward; Adler, Werner; Wichmann, Manfred; Heckmann, Siegfried Martin

2017-04-01

Accurate virtual implant models are a necessity for the fabrication of precisely fitting superstructures. The purpose of this in vitro study was to evaluate different methods with which to build an accurate virtual model of a 3-dimensional implant in the oral cavity; this model would then be used for iterative computer-aided design and computer-aided manufacturing (CAD-CAM) procedures. A titanium master model with 3 rigidly connected implants was manufactured and digitized with a noncontact industrial scanner to obtain a virtual master model. Impressions of the master model with the implant position locators (IPL) were made using vinyl siloxanether material. The impressions were scanned (Impression scanning technique group). For the transfer technique and pick-up technique groups (each group n=20), implant analogs were inserted into the impression copings, impressions were made using polyether, and casts were poured in Type 4 gypsum. The IPLs were screwed into the analogs and scanned. To compare the virtual master model with each virtual test model, a CAD interactive software, ATOS professional, was applied. The Kruskal-Wallis test was subsequently used to determine the overall difference between groups, with the Mann-Whitney U test used for pairwise comparisons. Through Bonferroni correction, the α-level was set to .017. The outcome revealed a significant difference among the 3 groups (P<.01) in terms of accuracy. With regard to total deviation, for all axes, the transfer technique generated the greatest divergence, 0.078 mm (±0.022), compared with the master model. Deviation with the pick-up technique was 0.041 mm (±0.009), with impression scanning generating the most accurate models with a deviation of 0.022 mm (±0.007). The impression scanning method improved the precision of CAD-CAM-fabricated superstructures. Copyright © 2016 Editorial Council for the Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.

SU-E-T-398: Feasibility of Automated Tools for Robustness Evaluation of Advanced Photon and Proton Techniques in Oropharyngeal Cancer

DOE Office of Scientific and Technical Information (OSTI.GOV)

Liu, H; Liang, X; Kalbasi, A

2014-06-01

Purpose: Advanced radiotherapy (RT) techniques such as proton pencil beam scanning (PBS) and photon-based volumetric modulated arc therapy (VMAT) have dosimetric advantages in the treatment of head and neck malignancies. However, anatomic or alignment changes during treatment may limit robustness of PBS and VMAT plans. We assess the feasibility of automated deformable registration tools for robustness evaluation in adaptive PBS and VMAT RT of oropharyngeal cancer (OPC). Methods: We treated 10 patients with bilateral OPC with advanced RT techniques and obtained verification CT scans with physician-reviewed target and OAR contours. We generated 3 advanced RT plans for each patient: protonmore » PBS plan using 2 posterior oblique fields (2F), proton PBS plan using an additional third low-anterior field (3F), and a photon VMAT plan using 2 arcs (Arc). For each of the planning techniques, we forward calculated initial (Ini) plans on the verification scans to create verification (V) plans. We extracted DVH indicators based on physician-generated contours for 2 target and 14 OAR structures to investigate the feasibility of two automated tools (contour propagation (CP) and dose deformation (DD)) as surrogates for routine clinical plan robustness evaluation. For each verification scan, we compared DVH indicators of V, CP and DD plans in a head-to-head fashion using Student's t-test. Results: We performed 39 verification scans; each patient underwent 3 to 6 verification scan. We found no differences in doses to target or OAR structures between V and CP, V and DD, and CP and DD plans across all patients (p > 0.05). Conclusions: Automated robustness evaluation tools, CP and DD, accurately predicted dose distributions of verification (V) plans using physician-generated contours. These tools may be further developed as a potential robustness screening tool in the workflow for adaptive treatment of OPC using advanced RT techniques, reducing the need for physician-generated contours.« less

SU-E-J-240: Development of a Novel 4D MRI Sequence for Real-Time Liver Tumor Tracking During Radiotherapy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhuang, L; Burmeister, J; Ye, Y

2015-06-15

Purpose: To develop a Novel 4D MRI Technique that is feasible for realtime liver tumor tracking during radiotherapy. Methods: A volunteer underwent an abdominal 2D fast EPI coronal scan on a 3.0T MRI scanner (Siemens Inc., Germany). An optimal set of parameters was determined based on image quality and scan time. A total of 23 slices were scanned to cover the whole liver in the test scan. For each scan position, the 2D images were retrospectively sorted into multiple phases based on breathing signal extracted from the images. Consequently the 2D slices with same phase numbers were stacked to formmore » one 3D image. Multiple phases of 3D images formed the 4D MRI sequence representing one breathing cycle. Results: The optimal set of scan parameters were: TR= 57ms, TE= 19ms, FOV read= 320mm and flip angle= 30°, which resulted in a total scan time of 14s for 200 frames (FMs) per slice and image resolution of (2.5mm,2.5mm,5.0mm) in three directions. Ten phases of 3D images were generated, each of which had 23 slices. Based on our test scan, only 100FMs were necessary for the phase sorting process which may lower the scan time to 7s/100FMs/slice. For example, only 5 slices/35s are necessary for a 4D MRI scan to cover liver tumor size ≤ 2cm leading to the possibility of tumor trajectory tracking every 35s during treatment. Conclusion: The novel 4D MRI technique we developed can reconstruct a 4D liver MRI sequence representing one breathing cycle (7s/ slice) without an external monitor. This technique can potentially be used for real-time liver tumor tracking during radiotherapy.« less

Comparison of 3D laser-based photonic scans and manual anthropometric measurements of body size and shape in a validation study of 123 young Swiss men

PubMed Central

Zwahlen, Marcel; Wells, Jonathan C.; Bender, Nicole; Henneberg, Maciej

2017-01-01

Background Manual anthropometric measurements are time-consuming and challenging to perform within acceptable intra- and inter-individual error margins in large studies. Three-dimensional (3D) laser body scanners provide a fast and precise alternative: within a few seconds the system produces a 3D image of the body topography and calculates some 150 standardised body size measurements. Objective The aim was to enhance the small number of existing validation studies and compare scan and manual techniques based on five selected measurements. We assessed the agreement between two repeated measurements within the two methods, analysed the direct agreement between the two methods, and explored the differences between the techniques when used in regressions assessing the effect of health related determinants on body shape indices. Methods We performed two repeated body scans on 123 volunteering young men using a Vitus Smart XXL body scanner. We manually measured height, waist, hip, buttock, and chest circumferences twice for each participant according to the WHO guidelines. The participants also filled in a basic questionnaire. Results Mean differences between the two scan measurements were smaller than between the two manual measurements, and precision as well as intra-class correlation coefficients were higher. Both techniques were strongly correlated. When comparing means between both techniques we found significant differences: Height was systematically shorter by 2.1 cm, whereas waist, hip and bust circumference measurements were larger in the scans by 1.17–4.37 cm. In consequence, body shape indices also became larger and the prevalence of overweight was greater when calculated from the scans. Between 4.1% and 7.3% of the probands changed risk category from normal to overweight when classified based on the scans. However, when employing regression analyses the two measurement techniques resulted in very similar coefficients, confidence intervals, and p-values. Conclusion For performing a large number of measurements in a large group of probands in a short time, body scans generally showed good feasibility, reliability, and validity in comparison to manual measurements. The systematic differences between the methods may result from their technical nature (contact vs. non-contact). PMID:28289559

Institutionalizing Environmental Scanning in the ED QUEST Process.

ERIC Educational Resources Information Center

Morrison, James L.

An environmental scanning system is structured to identify and evaluate trends, events, and emerging issues. QUEST represents the quick environmental scanning technique, and an ED QUEST process enables an educational organization to clarify its future and define its options. This paper describes how an educational organization can establish an…

Scanning probe recognition microscopy investigation of tissue scaffold properties

PubMed Central

Fan, Yuan; Chen, Qian; Ayres, Virginia M; Baczewski, Andrew D; Udpa, Lalita; Kumar, Shiva

2007-01-01

Scanning probe recognition microscopy is a new scanning probe microscopy technique which enables selective scanning along individual nanofibers within a tissue scaffold. Statistically significant data for multiple properties can be collected by repetitively fine-scanning an identical region of interest. The results of a scanning probe recognition microscopy investigation of the surface roughness and elasticity of a series of tissue scaffolds are presented. Deconvolution and statistical methods were developed and used for data accuracy along curved nanofiber surfaces. Nanofiber features were also independently analyzed using transmission electron microscopy, with results that supported the scanning probe recognition microscopy-based analysis. PMID:18203431

Scanning probe recognition microscopy investigation of tissue scaffold properties.

PubMed

Fan, Yuan; Chen, Qian; Ayres, Virginia M; Baczewski, Andrew D; Udpa, Lalita; Kumar, Shiva

2007-01-01

Scanning probe recognition microscopy is a new scanning probe microscopy technique which enables selective scanning along individual nanofibers within a tissue scaffold. Statistically significant data for multiple properties can be collected by repetitively fine-scanning an identical region of interest. The results of a scanning probe recognition microscopy investigation of the surface roughness and elasticity of a series of tissue scaffolds are presented. Deconvolution and statistical methods were developed and used for data accuracy along curved nanofiber surfaces. Nanofiber features were also independently analyzed using transmission electron microscopy, with results that supported the scanning probe recognition microscopy-based analysis.

Monitoring damage growth in titanium matrix composites using acoustic emission

NASA Technical Reports Server (NTRS)

Bakuckas, J. G., Jr.; Prosser, W. H.; Johnson, W. S.

1993-01-01

The application of the acoustic emission (AE) technique to locate and monitor damage growth in titanium matrix composites (TMC) was investigated. Damage growth was studied using several optical techniques including a long focal length, high magnification microscope system with image acquisition capabilities. Fracture surface examinations were conducted using a scanning electron microscope (SEM). The AE technique was used to locate damage based on the arrival times of AE events between two sensors. Using model specimens exhibiting a dominant failure mechanism, correlations were established between the observed damage growth mechanisms and the AE results in terms of the events amplitude. These correlations were used to monitor the damage growth process in laminates exhibiting multiple modes of damage. Results revealed that the AE technique is a viable and effective tool to monitor damage growth in TMC.

Influence of different treatment techniques on radiation dose to the LAD coronary artery

PubMed Central

Nieder, Carsten; Schill, Sabine; Kneschaurek, Peter; Molls, Michael

2007-01-01

Background The purpose of this proof-of-principle study was to test the ability of an intensity-modulated radiotherapy (IMRT) technique to reduce the radiation dose to the heart plus the left ventricle and a coronary artery. Radiation-induced heart disease might be a serious complication in long-term cancer survivors. Methods Planning CT scans from 6 female patients were available. They were part of a previous study of mediastinal IMRT for target volumes used in lymphoma treatment that included 8 patients and represent all cases where the left anterior descending coronary artery (LAD) could be contoured. We compared 6 MV AP/PA opposed fields to a 3D conformal 4-field technique and an optimised 7-field step-and-shoot IMRT technique and evaluated DVH's for several structures. The planning system was BrainSCAN 5.21 (BrainLAB, Heimstetten, Germany). Results IMRT maintained target volume coverage but resulted in better dose reduction to the heart, left ventricle and LAD than the other techniques. Selective dose reduction could be accomplished, although not to the degree initially attempted. The median LAD dose was approximately 50% lower with IMRT. In 5 out of 6 patients, IMRT was the best technique with regard to heart sparing. Conclusion IMRT techniques are able to reduce the radiation dose to the heart. In addition to dose reduction to whole heart, individualised dose distributions can be created, which spare, e.g., one ventricle plus one of the coronary arteries. Certain patients with well-defined vessel pathology might profit from an approach of general heart sparing with further selective dose reduction, accounting for the individual aspects of pre-existing damage. PMID:17547777

Formation of indomethacin-saccharin cocrystals using supercritical fluid technology.

PubMed

Padrela, Luis; Rodrigues, Miguel A; Velaga, Sitaram P; Matos, Henrique A; de Azevedo, Edmundo Gomes

2009-08-12

The main objective of the present work is to check the feasibility of supercritical fluid (SCF) technologies in the screening and design of cocrystals (novel crystalline solids). The cocrystal formation tendencies in three different SCF techniques, focusing on distinct supercritical fluid properties - solvent, anti-solvent and atomization enhancer - were investigated. The effect of processing parameters on the cocrystal formation behaviour and particle properties in these techniques was also studied. A recently reported indomethacin-saccharin (IND-SAC) cocrystalline system was our model system. A 1:1 molar ratio of indomethacin (gamma-form) and saccharin was used as a starting material. The SCF techniques employed in the study include the CSS technique (cocrystallization with supercritical solvent), the SAS technique (supercritical anti-solvent), and the AAS technique (atomization and anti-solvent). The resulting cocrystalline phase was identified using differential scanning calorimetry (DSC), powder X-ray diffraction (PXRD), and Fourier transform-Raman (FT-Raman). The particle morphologies and size distributions were determined using scanning electron microscopy (SEM) and aerosizer, respectively. The pure IND-SAC cocrystals were obtained from SAS and AAS processes, whilst partial to no cocrystal formation occurred in the CSS process. However, no remarkable differences were observed in terms of cocrystal formation at different processing conditions in SAS and AAS processes. Particles from CSS processes were agglomerated and large, whilst needle-to-block-shaped and spherical particles were obtained from SAS and AAS processes, respectively. The particle size distribution of these particles was 0.2-5microm. Particulate IND-SAC cocrystals with different morphologies and sizes (nano-to-micron) were produced using supercritical fluid techniques. This work demonstrates the potential of SCF technologies as screening methods for cocrystals with possibilities for particle engineering.

Calculation and Prediction of the Effect of Respiratory Motion on Whole Breast Radiation Therapy Dose Distributions

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cao Junsheng; Roeske, John C.; Chmura, Steve J.

2009-07-01

The standard treatment technique used for whole-breast irradiation can result in undesirable dose distributions in the treatment site, leading to skin reaction/fibrosis and pulmonary and cardiac toxicities. Hence, the technique has evolved from conventional wedged technique (CWT) to segment intensity-modulated radiation therapy (SIMRT) and beamlet IMRT (IMRT). However, these newer techniques feature more highly modulated dose distributions that may be affected by respiration. The purpose of this work was to conduct a simple study of the clinical impact of respiratory motion on breast radiotherapy dose distributions for the three treatment planning techniques. The ultimate goal was to determine which patientsmore » would benefit most from the use of motion management. Eight patients with early-stage breast cancer underwent a free-breathing (FB) computed tomography (CT) simulation, with medial and lateral markers placed on the skin. Two additional CT scans were obtained at the end of inspiration (EI) and the end of expiration (EE). The FB-CT scan was used to develop treatment plans using each technique. Each plan was then applied to EI and EE-CT scans. Compared with the FB CT scan, the medial markers moved up to 1.8 cm in the anterior-superior direction at the end of inspiration (EI-scan), and on average 8 mm. The CWT and SIMRT techniques were not 'sensitive' to respiratory motion, because the % clinical target volume (CTV) receiving 95% of the prescription dose (V{sub 95%}) remained constant for both techniques. For patients that had large respiratory motion indicated by marker movement >0.6 cm, differences in coverage of the CTV at the V100% between FB and EI for beamlet IMRT plans were on the order of >10% and up to 18%. A linear model was developed to relate the dosimetric coverage difference introduced by respiration with the motion information. With this model, the dosimetric coverage difference introduced by respiratory motion could be evaluated during patient CT simulation. An appropriate treatment method can be chosen after the simulation.« less

Miniaturized Laser Heterodyne Radiometer for Measurements of CO2 in the Atmospheric Column

NASA Technical Reports Server (NTRS)

Wilson, E. L.; Mclinden, M. L.; Miller, J. H.; Allan, G. R.; Lott, L. E.; Melroy, H. R.; Clarke, G. B.

2013-01-01

We have developed a low-cost, miniaturized laser heterodyne radiometer for highly sensitive measurements of carbon dioxide (CO2) in the atmospheric column. In this passive design, sunlight that has undergone absorption by CO2 in the atmosphere is collected and mixed with continuous wave laser light that is step-scanned across the absorption feature centered at 1,573.6 nm. The resulting radio frequency beat signal is collected as a function of laser wavelength, from which the total column mole fraction can be de-convolved. We are expanding this technique to include methane (CH4) and carbon monoxide (CO), and with minor modifications, this technique can be expanded to include species such as water vapor (H2O) and nitrous oxide (N2O).

Change detection of medical images using dictionary learning techniques and PCA

NASA Astrophysics Data System (ADS)

Nika, Varvara; Babyn, Paul; Zhu, Hongmei

2014-03-01

Automatic change detection methods for identifying the changes of serial MR images taken at different times are of great interest to radiologists. The majority of existing change detection methods in medical imaging, and those of brain images in particular, include many preprocessing steps and rely mostly on statistical analysis of MRI scans. Although most methods utilize registration software, tissue classification remains a difficult and overwhelming task. Recently, dictionary learning techniques are used in many areas of image processing, such as image surveillance, face recognition, remote sensing, and medical imaging. In this paper we present the Eigen-Block Change Detection algorithm (EigenBlockCD). It performs local registration and identifies the changes between consecutive MR images of the brain. Blocks of pixels from baseline scan are used to train local dictionaries that are then used to detect changes in the follow-up scan. We use PCA to reduce the dimensionality of the local dictionaries and the redundancy of data. Choosing the appropriate distance measure significantly affects the performance of our algorithm. We examine the differences between L1 and L2 norms as two possible similarity measures in the EigenBlockCD. We show the advantages of L2 norm over L1 norm theoretically and numerically. We also demonstrate the performance of the EigenBlockCD algorithm for detecting changes of MR images and compare our results with those provided in recent literature. Experimental results with both simulated and real MRI scans show that the EigenBlockCD outperforms the previous methods. It detects clinical changes while ignoring the changes due to patient's position and other acquisition artifacts.

Laser Measurement Of Convective-Heat-Transfer Coefficient

NASA Technical Reports Server (NTRS)

Porro, A. Robert; Hingst, Warren R.; Chriss, Randall M.; Seablom, Kirk D.; Keith, Theo G., Jr.

1994-01-01

Coefficient of convective transfer of heat at spot on surface of wind-tunnel model computed from measurements acquired by developmental laser-induced-heat-flux technique. Enables non-intrusive measurements of convective-heat-transfer coefficients at many points across surfaces of models in complicated, three-dimensional, high-speed flows. Measurement spot scanned across surface of model. Apparatus includes argon-ion laser, attenuator/beam splitter electronic shutter infrared camera, and subsystem.

Night Vision Goggle Training; Development and Production of Six Video Programs

DTIC Science & Technology

1992-11-01

SUIUECT TERMS Multimedia Video production iS. NUMBER OF PAGES Aeral photography Night vision Videodisc 18 Image Intensification Night vision goggles...reference tool on the squadron or wing demonstrates NVG field of view, field of level. The programs run approximately ten regard, scan techniques, image...training device modalities. These The production of a videodisc that modalities include didactic and video will serve as an NVG audio-visual database

Radionuclide-anesthetic flow study: a new technique for the study of regional anesthesia

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bauman, J.M.; Middaugh, R.E.; Cawthon, M.A.

1986-09-01

A new technique to study the dynamics of in vivo distribution of regional anesthetics is described. Five hundred microcuries of technetium-99m diethylenetriaminepentaacetic acid (DTPA) added to the anesthetic in a syringe prior to injection allows both dynamic and static imaging to assess the initial distribution of the injected anesthetic. Superimposed bone scans or transmission scans help delineate anatomy. The radionuclide-anesthetic flow study is a simple, safe technique to investigate both the spread of regional anesthetics and the factors that affect it.

Positron emission tomography to assess hypoxia and perfusion in lung cancer

PubMed Central

Verwer, Eline E; Boellaard, Ronald; van der Veldt, Astrid AM

2014-01-01

In lung cancer, tumor hypoxia is a characteristic feature, which is associated with a poor prognosis and resistance to both radiation therapy and chemotherapy. As the development of tumor hypoxia is associated with decreased perfusion, perfusion measurements provide more insight into the relation between hypoxia and perfusion in malignant tumors. Positron emission tomography (PET) is a highly sensitive nuclear imaging technique that is suited for non-invasive in vivo monitoring of dynamic processes including hypoxia and its associated parameter perfusion. The PET technique enables quantitative assessment of hypoxia and perfusion in tumors. To this end, consecutive PET scans can be performed in one scan session. Using different hypoxia tracers, PET imaging may provide insight into the prognostic significance of hypoxia and perfusion in lung cancer. In addition, PET studies may play an important role in various stages of personalized medicine, as these may help to select patients for specific treatments including radiation therapy, hypoxia modifying therapies, and antiangiogenic strategies. In addition, specific PET tracers can be applied for monitoring therapy. The present review provides an overview of the clinical applications of PET to measure hypoxia and perfusion in lung cancer. Available PET tracers and their characteristics as well as the applications of combined hypoxia and perfusion PET imaging are discussed. PMID:25493221

Development of a dual-energy computed tomography quality control program: Characterization of scanner response and definition of relevant parameters for a fast-kVp switching dual-energy computed tomography system.

PubMed

Nute, Jessica L; Jacobsen, Megan C; Stefan, Wolfgang; Wei, Wei; Cody, Dianna D

2018-04-01

A prototype QC phantom system and analysis process were developed to characterize the spectral capabilities of a fast kV-switching dual-energy computed tomography (DECT) scanner. This work addresses the current lack of quantitative oversight for this technology, with the goal of identifying relevant scan parameters and test metrics instrumental to the development of a dual-energy quality control (DEQC). A prototype elliptical phantom (effective diameter: 35 cm) was designed with multiple material inserts for DECT imaging. Inserts included tissue equivalent and material rods (including iodine and calcium at varying concentrations). The phantom was scanned on a fast kV-switching DECT system using 16 dual-energy acquisitions (CTDIvol range: 10.3-62 mGy) with varying pitch, rotation time, and tube current. The circular head phantom (22 cm diameter) was scanned using a similar protocol (12 acquisitions; CTDIvol range: 36.7-132.6 mGy). All acquisitions were reconstructed at 50, 70, 110, and 140 keV and using a water-iodine material basis pair. The images were evaluated for iodine quantification accuracy, stability of monoenergetic reconstruction CT number, noise, and positional constancy. Variance component analysis was used to identify technique parameters that drove deviations in test metrics. Variances were compared to thresholds derived from manufacturer tolerances to determine technique parameters that had a nominally significant effect on test metrics. Iodine quantification error was largely unaffected by any of the technique parameters investigated. Monoenergetic HU stability was found to be affected by mAs, with a threshold under which spectral separation was unsuccessful, diminishing the utility of DECT imaging. Noise was found to be affected by CTDIvol in the DEQC body phantom, and CTDIvol and mA in the DEQC head phantom. Positional constancy was found to be affected by mAs in the DEQC body phantom and mA in the DEQC head phantom. A streamlined scan protocol was developed to further investigate the effects of CTDIvol and rotation time while limiting data collection to the DEQC body phantom. Further data collection will be pursued to determine baseline values and statistically based failure thresholds for the validation of long-term DECT scanner performance. © 2018 American Association of Physicists in Medicine.

Quantification of left ventricular functional parameter values using 3D spiral bSSFP and through-time non-Cartesian GRAPPA.

PubMed

Barkauskas, Kestutis J; Rajiah, Prabhakar; Ashwath, Ravi; Hamilton, Jesse I; Chen, Yong; Ma, Dan; Wright, Katherine L; Gulani, Vikas; Griswold, Mark A; Seiberlich, Nicole

2014-09-11

The standard clinical acquisition for left ventricular functional parameter analysis with cardiovascular magnetic resonance (CMR) uses a multi-breathhold multi-slice segmented balanced SSFP sequence. Performing multiple long breathholds in quick succession for ventricular coverage in the short-axis orientation can lead to fatigue and is challenging in patients with severe cardiac or respiratory disorders. This study combines the encoding efficiency of a six-fold undersampled 3D stack of spirals balanced SSFP sequence with 3D through-time spiral GRAPPA parallel imaging reconstruction. This 3D spiral method requires only one breathhold to collect the dynamic data. Ten healthy volunteers were recruited for imaging at 3 T. The 3D spiral technique was compared against 2D imaging in terms of systolic left ventricular functional parameter values (Bland-Altman plots), total scan time (Welch's t-test) and qualitative image rating scores (Wilcoxon signed-rank test). Systolic left ventricular functional values were not significantly different (i.e. 3D-2D) between the methods. The 95% confidence interval for ejection fraction was -0.1 ± 1.6% (mean ± 1.96*SD). The total scan time for the 3D spiral technique was 48 s, which included one breathhold with an average duration of 14 s for the dynamic scan, plus 34 s to collect the calibration data under free-breathing conditions. The 2D method required an average of 5 min 40s for the same coverage of the left ventricle. The difference between 3D and 2D image rating scores was significantly different from zero (Wilcoxon signed-rank test, p < 0.05); however, the scores were at least 3 (i.e. average) or higher for 3D spiral imaging. The 3D through-time spiral GRAPPA method demonstrated equivalent systolic left ventricular functional parameter values, required significantly less total scan time and yielded acceptable image quality with respect to the 2D segmented multi-breathhold standard in this study. Moreover, the 3D spiral technique used just one breathhold for dynamic imaging, which is anticipated to reduce patient fatigue as part of the complete cardiac examination in future studies that include patients.

Evidence of dose saving in routine CT practice using iterative reconstruction derived from a national diagnostic reference level survey.

PubMed

Thomas, P; Hayton, A; Beveridge, T; Marks, P; Wallace, A

2015-09-01

To assess the influence and significance of the use of iterative reconstruction (IR) algorithms on patient dose in CT in Australia. We examined survey data submitted to the Australian Radiation Protection and Nuclear Safety Agency (ARPANSA) National Diagnostic Reference Level Service (NDRLS) during 2013 and 2014. We compared median survey dose metrics with categorization by scan region and use of IR. The use of IR results in a reduction in volume CT dose index of between 17% and 44% and a reduction in dose-length product of between 14% and 34% depending on the specific scan region. The reduction was highly significant (p < 0.001, Wilcoxon rank-sum test) for all six scan regions included in the NDRLS. Overall, 69% (806/1167) of surveys included in the analysis used IR. The use of IR in CT is achieving dose savings of 20-30% in routine practice in Australia. IR appears to be widely used by participants in the ARPANSA NDRLS with approximately 70% of surveys submitted employing this technique. This study examines the impact of the use of IR on patient dose in CT on a national scale.

Clinical applications of very high frequency ultrasound in ophthalmology

NASA Astrophysics Data System (ADS)

Silverman, Ronald H.; Coleman, D. Jackson; Reinstein, Dan Z.; Lizzi, Frederic L.

2004-05-01

The eye is ideally suited for diagnostic imaging with very high frequency (>35 MHz) ultrasound (VHFU) because of its peripheral location and cystic structure. VHFU allows high resolution visualization of pathologies affecting the anterior segment of the eye, including tumors, cysts, foreign bodies, and corneal pathologies. We developed a series of prototype instruments suitable for ophthalmic studies using both polymer and lithium niobate transducers, with digitization of radiofrequency echo data at up to 500 MHz. While initially using linear scan geometries, we subsequently developed an arc-shaped scan matched to the curvature of the 0.5-mm-thick cornea to circumvent the effect of specular deflection of the ultrasound beam produced by the corneas curved surface. This technique allowed us to obtain data across the entire cornea and determination of the thickness of each corneal layer, including the epithelium (approximately 50 microns in thickness) and the surgically induced interface produced in LASIK, the most common form of refractive surgery. By scanning in a series of meridians, and applying optimized signal processing strategies (deconvolution, analytic signal envelope determination), corneal pachymetric maps representing the local thickness of each layer can be generated and aid in diagnosis of surgically induced defects or refractive abnormalities.

Advanced sensor-simulation capability

NASA Astrophysics Data System (ADS)

Cota, Stephen A.; Kalman, Linda S.; Keller, Robert A.

1990-09-01

This paper provides an overview of an advanced simulation capability currently in use for analyzing visible and infrared sensor systems. The software system, called VISTAS (VISIBLE/INFRARED SENSOR TRADES, ANALYSES, AND SIMULATIONS) combines classical image processing techniques with detailed sensor models to produce static and time dependent simulations of a variety of sensor systems including imaging, tracking, and point target detection systems. Systems modelled to date include space-based scanning line-array sensors as well as staring 2-dimensional array sensors which can be used for either imaging or point source detection.

Quality assessment of the TLS data in conservation of monuments

NASA Astrophysics Data System (ADS)

Markiewicz, Jakub S.; Zawieska, Dorota

2015-06-01

Laser scanning has been recently confirming its high potential in the field of acquiring 3D data for architectural and engineering objects. The objective of this paper is to analyse the quality of the TLS data acquired for different surfaces of monumental objects, with consideration of distances and the scanning angles. Tests concerning the quality of the survey data and shapes of architectural objects, characterised by diversified curvature, structure and the uniformity of the surface, were performed. The obtained results proved that utilisation of terrestrial laser scanning techniques does not allow to achieve expected accuracy for some historical surfaces and it should be substituted by alternative, photogrammetric techniques. Therefore, the typology of constructions of historical objects is important not only for selection of the optimum technique of surveys, but also for its appropriate utilisation. The test objects were architectural details of the Main Hall of the Warsaw University of Technology. Scans were acquired using the 5006h scanner. Diversified geometry of scans was tested, and the relations between the distance and obtained accuracy were specified. In the case of numerous conservational works the precise surface reconstruction is often important, in order to specify damages. Therefore, the repeatability of obtained TLS results for selected surfaces was also tested. Different surfaces were analysed, which are composed of different materials having glittery elements and inhomogeneous structure. The obtained results and performed analyses revealed the high imperfections of the TLS technique applied for measuring surfaces of historical objects. The presented accuracy of measurements of projection of historical surfaces, obtained using the TLS technique may be applied by art conservators, museum professionals, archaeologists and other specialists, to perform wide analyses of historical heritage objects.

Analysis of calibration materials to improve dual-energy CT scanning for petrophysical applications

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ayyalasomavaiula, K.; McIntyre, D.; Jain, J.

2011-01-01

Dual energy CT-scanning is a rapidly emerging imaging technique employed in non-destructive evaluation of various materials. Although CT (Computerized Tomography) has been used for characterizing rocks and visualizing and quantifying multiphase flow through rocks for over 25 years, most of the scanning is done at a voltage setting above 100 kV for taking advantage of the Compton scattering (CS) effect, which responds to density changes. Below 100 kV the photoelectric effect (PE) is dominant which responds to the effective atomic numbers (Zeff), which is directly related to the photo electric factor. Using the combination of the two effects helps inmore » better characterization of reservoir rocks. The most common technique for dual energy CT-scanning relies on homogeneous calibration standards to produce the most accurate decoupled data. However, the use of calibration standards with impurities increases the probability of error in the reconstructed data and results in poor rock characterization. This work combines ICP-OES (inductively coupled plasma optical emission spectroscopy) and LIBS (laser induced breakdown spectroscopy) analytical techniques to quantify the type and level of impurities in a set of commercially purchased calibration standards used in dual-energy scanning. The Zeff data on the calibration standards with and without impurity data were calculated using the weighted linear combination of the various elements present and used in calculating Zeff using the dual energy technique. Results show 2 to 5% difference in predicted Zeff values which may affect the corresponding log calibrations. The effect that these techniques have on improving material identification data is discussed and analyzed. The workflow developed in this paper will translate to a more accurate material identification estimates for unknown samples and improve calibration of well logging tools.« less

Recovery of Background Structures in Nanoscale Helium Ion Microscope Imaging.

PubMed

Carasso, Alfred S; Vladár, András E

2014-01-01

This paper discusses a two step enhancement technique applicable to noisy Helium Ion Microscope images in which background structures are not easily discernible due to a weak signal. The method is based on a preliminary adaptive histogram equalization, followed by 'slow motion' low-exponent Lévy fractional diffusion smoothing. This combined approach is unexpectedly effective, resulting in a companion enhanced image in which background structures are rendered much more visible, and noise is significantly reduced, all with minimal loss of image sharpness. The method also provides useful enhancements of scanning charged-particle microscopy images obtained by composing multiple drift-corrected 'fast scan' frames. The paper includes software routines, written in Interactive Data Language (IDL),(1) that can perform the above image processing tasks.

Non-laser-based scanner for three-dimensional digitization of historical artifacts

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hahn, Daniel V.; Baldwin, Kevin C.; Duncan, Donald D

2007-05-20

A 3D scanner, based on incoherent illumination techniques, and associated data-processing algorithms are presented that can be used to scan objects at lateral resolutions ranging from 5 to100 {mu}m (or more) and depth resolutions of approximately 2 {mu}m.The scanner was designed with the specific intent to scan cuneiform tablets but can be utilized for other applications. Photometric stereo techniques are used to obtain both a surface normal map and a parameterized model of the object's bidirectional reflectance distribution function. The normal map is combined with height information,gathered by structured light techniques, to form a consistent 3D surface. Data from Lambertianmore » and specularly diffuse spherical objects are presented and used to quantify the accuracy of the techniques. Scans of a cuneiform tablet are also presented. All presented data are at a lateral resolution of 26.8 {mu}m as this is approximately the minimum resolution deemed necessary to accurately represent cuneiform.« less

Environmental scanning electron microscopy in cell biology.

PubMed

McGregor, J E; Staniewicz, L T L; Guthrie Neé Kirk, S E; Donald, A M

2013-01-01

Environmental scanning electron microscopy (ESEM) (1) is an imaging technique which allows hydrated, insulating samples to be imaged under an electron beam. The resolution afforded by this technique is higher than conventional optical microscopy but lower than conventional scanning electron microscopy (CSEM). The major advantage of the technique is the minimal sample preparation needed, making ESEM quick to use and the images less susceptible to the artifacts that the extensive sample preparation usually required for CSEM may introduce. Careful manipulation of both the humidity in the microscope chamber and the beam energy are nevertheless essential to prevent dehydration and beam damage artifacts. In some circumstances it is possible to image live cells in the ESEM (2).In the following sections we introduce the fundamental principles of ESEM imaging before presenting imaging protocols for plant epidermis, mammalian cells, and bacteria. In the first two cases samples are imaged using the secondary electron (topographic) signal, whereas a transmission technique is employed to image bacteria.

Accelerated damage visualization using binary search with fixed pitch-catch distance laser ultrasonic scanning

NASA Astrophysics Data System (ADS)

Park, Byeongjin; Sohn, Hoon

2017-07-01

Laser ultrasonic scanning, especially full-field wave propagation imaging, is attractive for damage visualization thanks to its noncontact nature, sensitivity to local damage, and high spatial resolution. However, its practicality is limited because scanning at a high spatial resolution demands a prohibitively long scanning time. Inspired by binary search, an accelerated damage visualization technique is developed to visualize damage with a reduced scanning time. The pitch-catch distance between the excitation point and the sensing point is also fixed during scanning to maintain a high signal-to-noise ratio (SNR) of measured ultrasonic responses. The approximate damage boundary is identified by examining the interactions between ultrasonic waves and damage observed at the scanning points that are sparsely selected by a binary search algorithm. Here, a time-domain laser ultrasonic response is transformed into a spatial ultrasonic domain response using a basis pursuit approach so that the interactions between ultrasonic waves and damage, such as reflections and transmissions, can be better identified in the spatial ultrasonic domain. Then, the area inside the identified damage boundary is visualized as damage. The performance of the proposed damage visualization technique is validated excusing a numerical simulation performed on an aluminum plate with a notch and experiments performed on an aluminum plate with a crack and a wind turbine blade with delamination. The proposed damage visualization technique accelerates the damage visualization process in three aspects: (1) the number of measurements that is necessary for damage visualization is dramatically reduced by a binary search algorithm; (2) the number of averaging that is necessary to achieve a high SNR is reduced by maintaining the wave propagation distance short; and (3) with the proposed technique, the same damage can be identified with a lower spatial resolution than the spatial resolution required by full-field wave propagation imaging.

Calibration, reconstruction, and rendering of cylindrical millimeter-wave image data

NASA Astrophysics Data System (ADS)

Sheen, David M.; Hall, Thomas E.

2011-05-01

Cylindrical millimeter-wave imaging systems and technology have been under development at the Pacific Northwest National Laboratory (PNNL) for several years. This technology has been commercialized, and systems are currently being deployed widely across the United States and internationally. These systems are effective at screening for concealed items of all types; however, new sensor designs, image reconstruction techniques, and image rendering algorithms could potentially improve performance. At PNNL, a number of specific techniques have been developed recently to improve cylindrical imaging methods including wideband techniques, combining data from full 360-degree scans, polarimetric imaging techniques, calibration methods, and 3-D data visualization techniques. Many of these techniques exploit the three-dimensionality of the cylindrical imaging technique by optimizing the depth resolution of the system and using this information to enhance detection. Other techniques, such as polarimetric methods, exploit scattering physics of the millimeter-wave interaction with concealed targets on the body. In this paper, calibration, reconstruction, and three-dimensional rendering techniques will be described that optimize the depth information in these images and the display of the images to the operator.

New advances in scanning microscopy and its application to study parasitic protozoa.

PubMed

de Souza, Wanderley; Attias, Marcia

2018-07-01

Scanning electron microscopy has been used to observe and study parasitic protozoa for at least 40 years. However, field emission electron sources, as well as improvements in lenses and detectors, brought the resolution power of scanning electron microscopes (SEM) to a new level. Parallel to the refinement of instruments, protocols for preservation of the ultrastructure, immunolabeling, exposure of cytoskeleton and inner structures of parasites and host cells were developed. This review is focused on protozoan parasites of medical and veterinary relevance, e.g., Toxoplasma gondii, Tritrichomonas foetus, Giardia intestinalis, and Trypanosoma cruzi, compilating the main achievements in describing the fine ultrastructure of their surface, cytoskeleton and interaction with host cells. Two new resources, namely, Helium Ion Microscopy (HIM) and Slice and View, using either Focused Ion Beam (FIB) abrasion or Microtome Serial Sectioning (MSS) within the microscope chamber, combined to backscattered electron imaging of fixed (chemically or by quick freezing followed by freeze substitution and resin embedded samples is bringing an exponential amount of valuable information. In HIM there is no need of conductive coating and the depth of field is much higher than in any field emission SEM. As for FIB- and MSS-SEM, high resolution 3-D models of areas and volumes larger than any other technique allows can be obtained. The main results achieved with all these technological tools and some protocols for sample preparation are included in this review. In addition, we included some results obtained with environmental/low vacuum scanning microscopy and cryo-scanning electron microscopy, both promising, but not yet largely employed SEM modalities. Copyright © 2018. Published by Elsevier Inc.

Internal fit of single crowns produced by CAD-CAM and lost-wax metal casting technique assessed by the triple-scan protocol.

PubMed

Dahl, Bjørn Einar; Rønold, Hans Jacob; Dahl, Jon E

2017-03-01

Whether single crowns produced by computer-aided design and computer-aided manufacturing (CAD-CAM) have an internal fit comparable to crowns made by lost-wax metal casting technique is unknown. The purpose of this in vitro study was to compare the internal fit of single crowns produced with the lost-wax and metal casting technique with that of single crowns produced with the CAD-CAM technique. The internal fit of 5 groups of single crowns produced with the CAD-CAM technique was compared with that of single crowns produced in cobalt-chromium with the conventional lost-wax and metal casting technique. Comparison was performed using the triple-scan protocol; scans of the master model, the crown on the master model, and the intaglio of the crown were superimposed and analyzed with computer software. The 5 groups were milled presintered zirconia, milled hot isostatic pressed zirconia, milled lithium disilicate, milled cobalt-chromium, and laser-sintered cobalt-chromium. The cement space in both the mesiodistal and buccopalatal directions was statistically smaller (P<.05) for crowns made by the conventional lost-wax and metal casting technique compared with that of crowns produced by the CAD-CAM technique. Single crowns made using the conventional lost-wax and metal casting technique have better internal fit than crowns produced using the CAD-CAM technique. Copyright © 2016 Editorial Council for the Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.

Surgical Techniques for the Reconstruction of Medial Collateral Ligament and Posteromedial Corner Injuries of the Knee: A Systematic Review.

PubMed

DeLong, Jeffrey M; Waterman, Brian R

2015-11-01

To systematically review reconstruction techniques of the medial collateral ligament (MCL) and associated medial structures of the knee (e.g., posterior oblique ligament). A systematic review of Medline/PubMed Database (1966 to November 2013), reference list scanning and citation searches of included articles, and manual searches of high-impact journals (2000 to July 2013) and conference proceedings (2009 to July 2013) were performed to identify publications describing MCL reconstruction techniques of the knee. Exclusion criteria included (1) MCL primary repair techniques or advancement procedures, (2) lack of clear description of MCL reconstruction technique, (3) animal models, (4) nonrelevant study design, (5) and foreign language articles without available translation. After review of 4,600 references, 25 publications with 359 of 388 patients (92.5%) were isolated for analysis, including 18 single-bundle MCL and 10 double-bundle reconstruction techniques. Only 2 techniques were classified as anatomic reconstructions, and clinical and objective outcomes (n = 28; 100% <3 mm side-to-side difference [SSD]) were superior to those with nonanatomic reconstruction (n = 182; 79.1% <3 mm SSD) and tendon transfer techniques (n = 114; 52.6% <3 mm SSD). This systematic review demonstrated that numerous medial reconstruction techniques have been used in the treatment of isolated and combined medial knee injuries in the existent literature. Many variations exist among reconstruction techniques and may differ by graft choices, method of fixation, number of bundles, tensioning protocol, and degree of anatomic restoration of medial and posteromedial corner knee restraints. Further studies are required to better ascertain the comparative clinical outcomes with anatomic, non-anatomic, and tendon transfer techniques for medial knee reconstruction. Level IV, systematic review of level IV studies and surgical techniques. Published by Elsevier Inc.

Local dynamic range compensation for scanning electron microscope imaging system by sub-blocking multiple peak HE with convolution.

PubMed

Sim, K S; Teh, V; Tey, Y C; Kho, T K

2016-11-01

This paper introduces new development technique to improve the Scanning Electron Microscope (SEM) image quality and we name it as sub-blocking multiple peak histogram equalization (SUB-B-MPHE) with convolution operator. By using this new proposed technique, it shows that the new modified MPHE performs better than original MPHE. In addition, the sub-blocking method consists of convolution operator which can help to remove the blocking effect for SEM images after applying this new developed technique. Hence, by using the convolution operator, it effectively removes the blocking effect by properly distributing the suitable pixel value for the whole image. Overall, the SUB-B-MPHE with convolution outperforms the rest of methods. SCANNING 38:492-501, 2016. © 2015 Wiley Periodicals, Inc. © Wiley Periodicals, Inc.

Assessment of probability of detection of delaminations in fiber-reinforced composites

NASA Technical Reports Server (NTRS)

Chern, E. J.; Chu, H. P.; Yang, J. N.

1991-01-01

Delamination is one of the critical defects in composite materials and structures. An ultrasonic C-scan imaging technique which maps out the acoustic impedance mismatched areas with respect to the sample coordinates, is particularly well suited for detecting and characterizing delaminations in composites. To properly interpret the results, it is necessary to correlate the indications with the detection limits and probability of detection (POD) of the ultrasonic C-scan imaging technique. The baseline information on the assessment of POD of delaminations in composite materials and structures is very beneficial to the evaluation of spacecraft materials. In this study, we review the principle of POD, describe the laboratory set-up and procedure, and present the experimental results as well as assessment of POD of delaminations in fiber reinforced composite panels using ultrasonic C-scan techniques.

High-speed massively parallel scanning

DOEpatents

Decker, Derek E [Byron, CA

2010-07-06

A new technique for recording a series of images of a high-speed event (such as, but not limited to: ballistics, explosives, laser induced changes in materials, etc.) is presented. Such technique(s) makes use of a lenslet array to take image picture elements (pixels) and concentrate light from each pixel into a spot that is much smaller than the pixel. This array of spots illuminates a detector region (e.g., film, as one embodiment) which is scanned transverse to the light, creating tracks of exposed regions. Each track is a time history of the light intensity for a single pixel. By appropriately configuring the array of concentrated spots with respect to the scanning direction of the detection material, different tracks fit between pixels and sufficient lengths are possible which can be of interest in several high-speed imaging applications.

Rapid calibrated high-resolution hyperspectral imaging using tunable laser source

NASA Astrophysics Data System (ADS)

Nguyen, Lam K.; Margalith, Eli

2009-05-01

We present a novel hyperspectral imaging technique based on tunable laser technology. By replacing the broadband source and tunable filters of a typical NIR imaging instrument, several advantages are realized, including: high spectral resolution, highly variable field-of-views, fast scan-rates, high signal-to-noise ratio, and the ability to use optical fiber for efficient and flexible sample illumination. With this technique, high-resolution, calibrated hyperspectral images over the NIR range can be acquired in seconds. The performance of system features will be demonstrated on two example applications: detecting melamine contamination in wheat gluten and separating bovine protein from wheat protein in cattle feed.

Tip-enhanced near-field optical microscopy

PubMed Central

Mauser, Nina; Hartschuh, Achim

2013-01-01

Tip-enhanced near-field optical microscopy (TENOM) is a scanning probe technique capable of providing a broad range of spectroscopic information on single objects and structured surfaces at nanometer spatial resolution and with highest detection sensitivity. In this review, we first illustrate the physical principle of TENOM that utilizes the antenna function of a sharp probe to efficiently couple light to excitations on nanometer length scales. We then discuss the antenna-induced enhancement of different optical sample responses including Raman scattering, fluorescence, generation of photocurrent and electroluminescence. Different experimental realizations are presented and several recent examples that demonstrate the capabilities of the technique are reviewed. PMID:24100541

Effects of Passive Porosity on Interacting Vortex Flows At Supersonic Speeds

NASA Technical Reports Server (NTRS)

Erickson, Gary E.

2000-01-01

A wind tunnel experiment was conducted in the NASA Langley Research Center (LaRC) Unitary Plan Wind Tunnel (UPWT) to determine the effects of passive surface porosity on vortex flow interaction about a general research fighter configuration at supersonic speeds. Optical flow measurement and flow visualization techniques were used and included pressure-sensitive paint (PSP), schlieren, and laser vapor screen (LVS) These techniques were combined with force and moment and conventional electronically-scanned pressure (ESP) measurements to quantify and to visualize the effects of flow-through porosity applied to a wing leading-edge extension (LEX) mounted to a 65 deg cropped delta wing model.

Room temperature chemical synthesis of lead selenide thin films with preferred orientation

NASA Astrophysics Data System (ADS)

Kale, R. B.; Sartale, S. D.; Ganesan, V.; Lokhande, C. D.; Lin, Yi-Feng; Lu, Shih-Yuan

2006-11-01

Room temperature chemical synthesis of PbSe thin films was carried out from aqueous ammoniacal solution using Pb(CH3COO)2 as Pb2+ and Na2SeSO3 as Se2- ion sources. The films were characterized by a various techniques including, X-ray diffraction (XRD), energy dispersive X-ray analysis (EDAX), scanning electron microscopy (SEM), transmission electron microscopy (TEM), high resolution transmission electron microscopy (HR-TEM), selected area electron diffraction (SAED), Fast Fourier transform (FFT) and UV-vis-NIR techniques. The study revealed that the PbSe thin film consists of preferentially oriented nanocubes with energy band gap of 0.5 eV.

D Digitization and Mapping of Heritage Monuments and Comparison with Historical Drawings

NASA Astrophysics Data System (ADS)

Fiorillo, F.; Remondino, F.; Barba, S.; Santoriello, A.; De Vita, C. B.; Casellato, A.

2013-07-01

The paper presents the integration of different 3D recording techniques and instruments to survey the archaeological area of Paestum (Italy). Paestum was included in the UNESCO World Heritage list since 1998, and still preserves the ruins of Greek and Roman times. Photogrammetry and terrestrial laser scanning (TLS) acquisitions were integrated in order to exploit the advantages of the 3D surveying techniques and produce digital models, orthoimages, maps and other geometric representations useful for archaeological, architectural and cultural touristic purposes. The obtained 3D results are then compared to historical representations to show the high quality of such ancient manual drawings.

Nano-material processing with laser radiation in the near field of a scanning probe tip

NASA Astrophysics Data System (ADS)

Jersch, J.; Demming, F.; Hildenhagen, J.; Dickmann, K.

1998-04-01

We report preliminary results of using a scanning probe microscope/laser combination to perform nanostructuring on insulator and metal surfaces in air. This technique enables processing of structures with a lateral resolution of approximately 10 nm. In this paper we present our last structuring results with both scanning tunnelling and scanning force microscopy. Some possible interaction mechanisms responsible for the structuring will be discussed.

Swept Line Electron Beam Annealing of Ion Implanted Semiconductors.

DTIC Science & Technology

1982-07-01

of my research to the mainstream of technology. The techniques used for beam processing are distinguished by their * ~.* beam source and method by...raster scanned CW lasers (CWL), pulsed ion beams (PI), area pulsed electron beams (PEE), raster scanned (RSEB) or multi - scanned electron beams (MSEB...where high quality or tailored profiles are required. Continuous wave lasers and multi -scanned or swept-line electron beams are the most likely candidates

Proton beam writing of long, arbitrary structures for micro/nano photonics and fluidics applications

NASA Astrophysics Data System (ADS)

Udalagama, Chammika; Teo, E. J.; Chan, S. F.; Kumar, V. S.; Bettiol, A. A.; Watt, F.

2011-10-01

The last decade has seen proton beam writing maturing into a versatile lithographic technique able to produce sub-100 nm, high aspect ratio structures with smooth side walls. However, many applications in the fields of photonics and fluidics require the fabrication of structures with high spatial resolution that extends over several centimetres. This cannot be achieved by purely magnetic or electrostatic beam scanning due to the large off-axis beam aberrations in high demagnification systems. As a result, this has limited us to producing long straight structures using a combination of beam and stage scanning. In this work we have: (1) developed an algorithm to include any arbitrary pattern into the writing process by using a more versatile combination of beam and stage scanning while (2) incorporating the use of the ubiquitous AutoCAD DXF (drawing exchange format) into the design process. We demonstrate the capability of this approach in fabricating structures such as Y-splitters, Mach-Zehnder modulators and microfluidic channels that are over several centimetres in length, in polymer. We also present optimisation of such parameters as scanning speed and scanning loops to improve on the surface roughness of the structures. This work opens up new possibilities of using CAD software in PBW for microphotonics and fluidics device fabrication.

Investigation of optical/infrared sensor techniques for application satellites

NASA Technical Reports Server (NTRS)

Kaufman, I.

1972-01-01

A method of scanning an optical sensor array by acoustic surface waves is discussed. Data cover detailed computer based analysis of the operation of a multielement acoustic surface-wave-scanned optical sensor, the development of design and operation techniques that were used to show the feasibility of an integrated array to design several such arrays, and experimental verification of a number of the calculations with discrete sensor devices.

SU-C-206-07: A Practical Sparse View Ultra-Low Dose CT Acquisition Scheme for PET Attenuation Correction in the Extended Scan Field-Of-View

DOE Office of Scientific and Technical Information (OSTI.GOV)

Miao, J; Fan, J; Gopinatha Pillai, A

Purpose: To further reduce CT dose, a practical sparse-view acquisition scheme is proposed to provide the same attenuation estimation as higher dose for PET imaging in the extended scan field-of-view. Methods: CT scans are often used for PET attenuation correction and can be acquired at very low CT radiation dose. Low dose techniques often employ low tube voltage/current accompanied with a smooth filter before backprojection to reduce CT image noise. These techniques can introduce bias in the conversion from HU to attenuation values, especially in the extended CT scan field-of-view (FOV). In this work, we propose an ultra-low dose CTmore » technique for PET attenuation correction based on sparse-view acquisition. That is, instead of an acquisition of full amount of views, only a fraction of views are acquired. We tested this technique on a 64-slice GE CT scanner using multiple phantoms. CT scan FOV truncation completion was performed based on the published water-cylinder extrapolation algorithm. A number of continuous views per rotation: 984 (full), 246, 123, 82 and 62 have been tested, corresponding to a CT dose reduction of none, 4x, 8x, 12x and 16x. We also simulated sparse-view acquisition by skipping views from the fully-acquired view data. Results: FBP reconstruction with Q. AC filter on reduced views in the full extended scan field-of-view possesses similar image quality to the reconstruction on acquired full view data. The results showed a further potential for dose reduction compared to the full acquisition, without sacrificing any significant attenuation support to the PET. Conclusion: With the proposed sparse-view method, one can potential achieve at least 2x more CT dose reduction compared to the current Ultra-Low Dose (ULD) PET/CT protocol. A pre-scan based dose modulation scheme can be combined with the above sparse-view approaches, which can even further reduce the CT scan dose during a PET/CT exam.« less

Three-Dimensional Ultrasonic Imaging Of The Cornea

NASA Technical Reports Server (NTRS)

Heyser, Rrichar C.; Rooney, James A.

1988-01-01

Proposed technique generates pictures of curved surfaces. Object ultrasonically scanned in raster pattern generated by scanning transmitter/receiver. Receiver turned on at frequent intervals to measure depth variations of scanned object. Used for medical diagnoses by giving images of small curved objects as cornea. Adaptable to other types of reflection measurementsystems such as sonar and radar.

Femtosecond Z-scan measurements of the nonlinear refractive index of fused silica

NASA Astrophysics Data System (ADS)

Zhang, Lin; Shi, Zhendong; Ma, Hua; Ren, Huan; Yuan, Quan; Ma, Yurong; Feng, Xiaoxuan; Chen, Bo; Yang, Yi

2018-01-01

Z-scan technology is a popular experimental technique for determining the nonlinear refractive index of the material. However, it encounters a great difficulty in measuring the weak nonlinear material like fused silica which is about two orders of magnitude below the nonlinear refractive index of most of the materials studied with the nanosecond and picosecond Z-scan methods. In this case, the change of refractive index introduced by accumulation of thermal effects cannot be neglected. In order to have a reliable measurement of the nonlinear refractive index, a metrology bench based on the femtosecond Z-scan technology is developed. The intensity modulation component and the differential measurement system are applied to guarantee the accuracy of the measuring system. Based on the femtosecond Z-scan theory, the femtosecond laser Z-scan technique is performed on fused silica, and the nonlinear refractive index of Fused silica is determined to be 9.2039×10-14esu for 800nm, 37fs pulse duration at I0=50GW/cm2 with a good repeatability of 6.7%.

Nonlinear optical characterization of graphite oxide thin film by open aperture Z-scan technique

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sreeja, V. G.; Reshmi, R.; Devasia, Sebin

In this paper we explore the structural characterization of graphite oxide powder prepared from graphite powder by oxidation via modified Hummers method. The nonlinear optical properties of the spin coated graphite oxide thin film is also explored by open aperture Z-Scan technique. Structural and physiochemical properties of the samples were investigated with the help of Fourier Transform Infrared Spectroscopy (FTIR) and Raman Spectroscopy (Raman).The results of FT-IR and Raman spectroscopy showed that the graphite is oxidized by strong oxidants and the oxygen atoms are introduced into the graphite layers forming C=C, O-H and –C-H groups. The synthesized sample has goodmore » crystalline nature with lesser defects. The nonlinear optical property of GO thin film was studied by open aperture Z-Scan technique using Q-switched Nd-Yag Laser at 532 nm. The Z-scan plot showed that the investigated GO thin film has saturable absorption behavior. The nonlinear absorption coefficient and saturation intensity were also estimated to explore its applications in Q switched mode locking laser systems.« less

TOPICAL REVIEW: Anatomical imaging for radiotherapy

NASA Astrophysics Data System (ADS)

Evans, Philip M.

2008-06-01

The goal of radiation therapy is to achieve maximal therapeutic benefit expressed in terms of a high probability of local control of disease with minimal side effects. Physically this often equates to the delivery of a high dose of radiation to the tumour or target region whilst maintaining an acceptably low dose to other tissues, particularly those adjacent to the target. Techniques such as intensity modulated radiotherapy (IMRT), stereotactic radiosurgery and computer planned brachytherapy provide the means to calculate the radiation dose delivery to achieve the desired dose distribution. Imaging is an essential tool in all state of the art planning and delivery techniques: (i) to enable planning of the desired treatment, (ii) to verify the treatment is delivered as planned and (iii) to follow-up treatment outcome to monitor that the treatment has had the desired effect. Clinical imaging techniques can be loosely classified into anatomic methods which measure the basic physical characteristics of tissue such as their density and biological imaging techniques which measure functional characteristics such as metabolism. In this review we consider anatomical imaging techniques. Biological imaging is considered in another article. Anatomical imaging is generally used for goals (i) and (ii) above. Computed tomography (CT) has been the mainstay of anatomical treatment planning for many years, enabling some delineation of soft tissue as well as radiation attenuation estimation for dose prediction. Magnetic resonance imaging is fast becoming widespread alongside CT, enabling superior soft-tissue visualization. Traditionally scanning for treatment planning has relied on the use of a single snapshot scan. Recent years have seen the development of techniques such as 4D CT and adaptive radiotherapy (ART). In 4D CT raw data are encoded with phase information and reconstructed to yield a set of scans detailing motion through the breathing, or cardiac, cycle. In ART a set of scans is taken on different days. Both allow planning to account for variability intrinsic to the patient. Treatment verification has been carried out using a variety of technologies including: MV portal imaging, kV portal/fluoroscopy, MVCT, conebeam kVCT, ultrasound and optical surface imaging. The various methods have their pros and cons. The four x-ray methods involve an extra radiation dose to normal tissue. The portal methods may not generally be used to visualize soft tissue, consequently they are often used in conjunction with implanted fiducial markers. The two CT-based methods allow measurement of inter-fraction variation only. Ultrasound allows soft-tissue measurement with zero dose but requires skilled interpretation, and there is evidence of systematic differences between ultrasound and other data sources, perhaps due to the effects of the probe pressure. Optical imaging also involves zero dose but requires good correlation between the target and the external measurement and thus is often used in conjunction with an x-ray method. The use of anatomical imaging in radiotherapy allows treatment uncertainties to be determined. These include errors between the mean position at treatment and that at planning (the systematic error) and the day-to-day variation in treatment set-up (the random error). Positional variations may also be categorized in terms of inter- and intra-fraction errors. Various empirical treatment margin formulae and intervention approaches exist to determine the optimum strategies for treatment in the presence of these known errors. Other methods exist to try to minimize error margins drastically including the currently available breath-hold techniques and the tracking methods which are largely in development. This paper will review anatomical imaging techniques in radiotherapy and how they are used to boost the therapeutic benefit of the treatment.

Laser-Based Slam with Efficient Occupancy Likelihood Map Learning for Dynamic Indoor Scenes

NASA Astrophysics Data System (ADS)

Li, Li; Yao, Jian; Xie, Renping; Tu, Jinge; Feng, Chen

2016-06-01

Location-Based Services (LBS) have attracted growing attention in recent years, especially in indoor environments. The fundamental technique of LBS is the map building for unknown environments, this technique also named as simultaneous localization and mapping (SLAM) in robotic society. In this paper, we propose a novel approach for SLAMin dynamic indoor scenes based on a 2D laser scanner mounted on a mobile Unmanned Ground Vehicle (UGV) with the help of the grid-based occupancy likelihood map. Instead of applying scan matching in two adjacent scans, we propose to match current scan with the occupancy likelihood map learned from all previous scans in multiple scales to avoid the accumulation of matching errors. Due to that the acquisition of the points in a scan is sequential but not simultaneous, there unavoidably exists the scan distortion at different extents. To compensate the scan distortion caused by the motion of the UGV, we propose to integrate a velocity of a laser range finder (LRF) into the scan matching optimization framework. Besides, to reduce the effect of dynamic objects such as walking pedestrians often existed in indoor scenes as much as possible, we propose a new occupancy likelihood map learning strategy by increasing or decreasing the probability of each occupancy grid after each scan matching. Experimental results in several challenged indoor scenes demonstrate that our proposed approach is capable of providing high-precision SLAM results.

Monte Carlo simulation for scanning technique with scattering foil free electron beam: A proof of concept study

PubMed Central

Sung, Wonmo; Park, Jong In; Kim, Jung-in; Carlson, Joel; Ye, Sung-Joon

2017-01-01

This study investigated the potential of a newly proposed scattering foil free (SFF) electron beam scanning technique for the treatment of skin cancer on the irregular patient surfaces using Monte Carlo (MC) simulation. After benchmarking of the MC simulations, we removed the scattering foil to generate SFF electron beams. Cylindrical and spherical phantoms with 1 cm boluses were generated and the target volume was defined from the surface to 5 mm depth. The SFF scanning technique with 6 MeV electrons was simulated using those phantoms. For comparison, volumetric modulated arc therapy (VMAT) plans were also generated with two full arcs and 6 MV photon beams. When the scanning resolution resulted in a larger separation between beams than the field size, the plan qualities were worsened. In the cylindrical phantom with a radius of 10 cm, the conformity indices, homogeneity indices and body mean doses of the SFF plans (scanning resolution = 1°) vs. VMAT plans were 1.04 vs. 1.54, 1.10 vs. 1.12 and 5 Gy vs. 14 Gy, respectively. Those of the spherical phantom were 1.04 vs. 1.83, 1.08 vs. 1.09 and 7 Gy vs. 26 Gy, respectively. The proposed SFF plans showed superior dose distributions compared to the VMAT plans. PMID:28493940

Monte Carlo simulation for scanning technique with scattering foil free electron beam: A proof of concept study.

PubMed

Sung, Wonmo; Park, Jong In; Kim, Jung-In; Carlson, Joel; Ye, Sung-Joon; Park, Jong Min

2017-01-01

This study investigated the potential of a newly proposed scattering foil free (SFF) electron beam scanning technique for the treatment of skin cancer on the irregular patient surfaces using Monte Carlo (MC) simulation. After benchmarking of the MC simulations, we removed the scattering foil to generate SFF electron beams. Cylindrical and spherical phantoms with 1 cm boluses were generated and the target volume was defined from the surface to 5 mm depth. The SFF scanning technique with 6 MeV electrons was simulated using those phantoms. For comparison, volumetric modulated arc therapy (VMAT) plans were also generated with two full arcs and 6 MV photon beams. When the scanning resolution resulted in a larger separation between beams than the field size, the plan qualities were worsened. In the cylindrical phantom with a radius of 10 cm, the conformity indices, homogeneity indices and body mean doses of the SFF plans (scanning resolution = 1°) vs. VMAT plans were 1.04 vs. 1.54, 1.10 vs. 1.12 and 5 Gy vs. 14 Gy, respectively. Those of the spherical phantom were 1.04 vs. 1.83, 1.08 vs. 1.09 and 7 Gy vs. 26 Gy, respectively. The proposed SFF plans showed superior dose distributions compared to the VMAT plans.

Self-calibrating d-scan: measuring ultrashort laser pulses on-target using an arbitrary pulse compressor.

PubMed

Alonso, Benjamín; Sola, Íñigo J; Crespo, Helder

2018-02-19

In most applications of ultrashort pulse lasers, temporal compressors are used to achieve a desired pulse duration in a target or sample, and precise temporal characterization is important. The dispersion-scan (d-scan) pulse characterization technique usually involves using glass wedges to impart variable, well-defined amounts of dispersion to the pulses, while measuring the spectrum of a nonlinear signal produced by those pulses. This works very well for broadband few-cycle pulses, but longer, narrower bandwidth pulses are much more difficult to measure this way. Here we demonstrate the concept of self-calibrating d-scan, which extends the applicability of the d-scan technique to pulses of arbitrary duration, enabling their complete measurement without prior knowledge of the introduced dispersion. In particular, we show that the pulse compressors already employed in chirped pulse amplification (CPA) systems can be used to simultaneously compress and measure the temporal profile of the output pulses on-target in a simple way, without the need of additional diagnostics or calibrations, while at the same time calibrating the often-unknown differential dispersion of the compressor itself. We demonstrate the technique through simulations and experiments under known conditions. Finally, we apply it to the measurement and compression of 27.5 fs pulses from a CPA laser.

Synchrotron imaging reveals bone healing and remodelling strategies in extinct and extant vertebrates

PubMed Central

Anné, Jennifer; Edwards, Nicholas P.; Wogelius, Roy A.; Tumarkin-Deratzian, Allison R.; Sellers, William I.; van Veelen, Arjen; Bergmann, Uwe; Sokaras, Dimosthenis; Alonso-Mori, Roberto; Ignatyev, Konstantin; Egerton, Victoria M.; Manning, Phillip L.

2014-01-01

Current understanding of bone healing and remodelling strategies in vertebrates has traditionally relied on morphological observations through the histological analysis of thin sections. However, chemical analysis may also be used in such interpretations, as different elements are known to be absorbed and used by bone for different physiological purposes such as growth and healing. These chemical signatures are beyond the detection limit of most laboratory-based analytical techniques (e.g. scanning electron microscopy). However, synchrotron rapid scanning–X-ray fluorescence (SRS–XRF) is an elemental mapping technique that uniquely combines high sensitivity (ppm), excellent sample resolution (20–100 µm) and the ability to scan large specimens (decimetre scale) approximately 3000 times faster than other mapping techniques. Here, we use SRS–XRF combined with microfocus elemental mapping (2–20 µm) to determine the distribution and concentration of trace elements within pathological and normal bone of both extant and extinct archosaurs (Cathartes aura and Allosaurus fragilis). Results reveal discrete chemical inventories within different bone tissue types and preservation modes. Chemical inventories also revealed detail of histological features not observable in thin section, including fine structures within the interface between pathological and normal bone as well as woven texture within pathological tissue. PMID:24806709

Multifarious applications of atomic force microscopy in forensic science investigations.

PubMed

Pandey, Gaurav; Tharmavaram, Maithri; Rawtani, Deepak; Kumar, Sumit; Agrawal, Y

2017-04-01

Forensic science is a wide field comprising of several subspecialties and uses methods derived from natural sciences for finding criminals and other evidence valid in a legal court. A relatively new area; Nano-forensics brings a new era of investigation in forensic science in which instantaneous results can be produced that determine various agents such as explosive gasses, biological agents and residues in different crime scenes and terrorist activity investigations. This can be achieved by applying Nanotechnology and its associated characterization techniques in forensic sciences. Several characterization techniques exist in Nanotechnology and nano-analysis is one such technique that is used in forensic science which includes Electron microscopes (EM) like Transmission (TEM) and Scanning (SEM), Raman microscopy (Micro -Raman) and Scanning Probe Microscopes (SPMs) like Atomic Force Microscope (AFM). Atomic force microscopy enables surface characterization of different materials by examining their morphology and mechanical properties. Materials that are immeasurable such as hair, body fluids, textile fibers, documents, polymers, pressure sensitive adhesives (PSAs), etc. are often encountered during forensic investigations. This review article will mainly focus on the use of AFM in the examination of different evidence such as blood stains, forged documents, human hair samples, ammunitions, explosives, and other such applications in the field of Forensic Science. Copyright © 2017 Elsevier B.V. All rights reserved.

A Comprehensive Workflow of Mass Spectrometry-Based Untargeted Metabolomics in Cancer Metabolic Biomarker Discovery Using Human Plasma and Urine

PubMed Central

Zou, Wei; She, Jianwen; Tolstikov, Vladimir V.

2013-01-01

Current available biomarkers lack sensitivity and/or specificity for early detection of cancer. To address this challenge, a robust and complete workflow for metabolic profiling and data mining is described in details. Three independent and complementary analytical techniques for metabolic profiling are applied: hydrophilic interaction liquid chromatography (HILIC–LC), reversed-phase liquid chromatography (RP–LC), and gas chromatography (GC). All three techniques are coupled to a mass spectrometer (MS) in the full scan acquisition mode, and both unsupervised and supervised methods are used for data mining. The univariate and multivariate feature selection are used to determine subsets of potentially discriminative predictors. These predictors are further identified by obtaining accurate masses and isotopic ratios using selected ion monitoring (SIM) and data-dependent MS/MS and/or accurate mass MSn ion tree scans utilizing high resolution MS. A list combining all of the identified potential biomarkers generated from different platforms and algorithms is used for pathway analysis. Such a workflow combining comprehensive metabolic profiling and advanced data mining techniques may provide a powerful approach for metabolic pathway analysis and biomarker discovery in cancer research. Two case studies with previous published data are adapted and included in the context to elucidate the application of the workflow. PMID:24958150

Abdominal ultrasound (image)

MedlinePlus

Abdominal ultrasound is a scanning technique used to image the interior of the abdomen. Like the X-ray, MRI, ... it has its place as a diagnostic tool. Ultrasound scans use high frequency sound waves to produce ...

X-Ray Micro-Computed Tomography of Apollo Samples as a Curation Technique Enabling Better Research

NASA Technical Reports Server (NTRS)

Ziegler, R. A.; Almeida, N. V.; Sykes, D.; Smith, C. L.

2014-01-01

X-ray micro-computed tomography (micro-CT) is a technique that has been used to research meteorites for some time and many others], and recently it is becoming a more common tool for the curation of meteorites and Apollo samples. Micro-CT is ideally suited to the characterization of astromaterials in the curation process as it can provide textural and compositional information at a small spatial resolution rapidly, nondestructively, and without compromising the cleanliness of the samples (e.g., samples can be scanned sealed in Teflon bags). This data can then inform scientists and curators when making and processing future sample requests for meteorites and Apollo samples. Here we present some preliminary results on micro-CT scans of four Apollo regolith breccias. Methods: Portions of four Apollo samples were used in this study: 14321, 15205, 15405, and 60639. All samples were 8-10 cm in their longest dimension and approximately equant. These samples were micro-CT scanned on the Nikon HMXST 225 System at the Natural History Museum in London. Scans were made at 205-220 kV, 135-160 microamps beam current, with an effective voxel size of 21-44 microns. Results: Initial examination of the data identify a variety of mineral clasts (including sub-voxel FeNi metal grains) and lithic clasts within the regolith breccias. Textural information within some of the lithic clasts was also discernable. Of particular interest was a large basalt clast (approx.1.3 cc) found within sample 60639, which appears to have a sub-ophitic texture. Additionally, internal void space, e.g., fractures and voids, is readily identifiable. Discussion: It is clear from the preliminary data that micro-CT analyses are able to identify important "new" clasts within the Apollo breccias, and better characterize previously described clasts or igneous samples. For example, the 60639 basalt clast was previously believed to be quite small based on its approx.0.5 sq cm exposure on the surface of the main mass. These scans show the clast to be approx.4.5 g, however (assuming a density of approx.3.5 g/cc). This is large enough for detailed studies including multiple geo-chronometers. This basalt clast is of particular interest as it is the largest Apollo 16 basalt, and it is the only mid-TiO2 basalt in the Apollo sample suite. By identifying the location of interesting clasts or grains within a sample, we will be able to make more informed decisions about where to cut a sample in order to best expose clasts of interest for future study. Moreover, knowing the location of internal defects (e.g., fractures) will allow more precise chipping and extraction of clasts or grains. By combining micro-CT scans with compositional techniques like micro x-ray fluorescence (particularly on sawn slabs), we will be able to provide even more comprehensive information to scientists trying to best select samples that fit their scientific needs.

Optical coherence tomography angiography in glaucoma care.

PubMed

Chansangpetch, Sunee; Lin, Shan C

2018-05-14

Rapid improvements in optical coherence tomography (OCT) technology have allowed for enhancement of both image resolution and scanning speed, and the development of vascular assessment modality. Optical coherence tomography angiography (OCTA) is the non-invasive in vivo imaging of the vasculature located within the retina and optic nerve head area. The principle of OCTA is to use the variations in OCT signals caused by moving particles as the contrast mechanism for imaging of flow. Several algorithms which aim to maximize the contrast signal and minimize the noise have been developed including the phase-based techniques, intensity-based techniques (e.g., split-spectrum amplitude decorrelation angiography (SSADA)), and complex-based techniques (e.g., optical microangiography (OMAG)). With its reliable technique, high image resolution, and current availability, OCTA has been widely used in the assessment of posterior segment diseases including glaucoma in which ocular perfusion dysfunction has been proposed as a pathophysiological mechanism. This review will provide the reader with information on the principle techniques of OCTA; the current literature on OCTA reproducibility; its applications to glaucoma detection and monitoring of progression; and the role of OCTA in the assessment of the vascular component in glaucoma pathogenesis.

Photoinduced force microscopy: A technique for hyperspectral nanochemical mapping

NASA Astrophysics Data System (ADS)

Murdick, Ryan A.; Morrison, William; Nowak, Derek; Albrecht, Thomas R.; Jahng, Junghoon; Park, Sung

2017-08-01

Advances in nanotechnology have intensified the need for tools that can characterize newly synthesized nanomaterials. A variety of techniques has recently been shown which combines atomic force microscopy (AFM) with optical illumination including tip-enhanced Raman spectroscopy (TERS), scattering-type scanning near-field optical microscopy (sSNOM), and photothermal induced resonance microscopy (PTIR). To varying degrees, these existing techniques enable optical spectroscopy with the nanoscale spatial resolution inherent to AFM, thereby providing nanochemical interrogation of a specimen. Here we discuss photoinduced force microscopy (PiFM), a recently developed technique for nanoscale optical spectroscopy that exploits image forces acting between an AFM tip and sample to detect wavelength-dependent polarization within the sample to generate absorption spectra. This approach enables ∼10 nm spatial resolution with spectra that show correlation with macroscopic optical absorption spectra. Unlike other techniques, PiFM achieves this high resolution with virtually no constraints on sample or substrate properties. The applicability of PiFM to a variety of archetypal systems is reported here, highlighting the potential of PiFM as a useful tool for a wide variety of industrial and academic investigations, including semiconducting nanoparticles, nanocellulose, block copolymers, and low dimensional systems, as well as chemical and morphological mixing at interfaces.

Preoperative and Postoperative CT Scan Assessment of Pterygomaxillary Junction in Patients Undergoing Le Fort I Osteotomy: Comparison of Pterygomaxillary Dysjunction Technique and Trimble Technique-A Pilot Study.

PubMed

Dadwal, Himani; Shanmugasundaram, S; Krishnakumar Raja, V B

2015-09-01

To determine the rate of complications and occurrence of pterygoid plate fractures comparing two techniques of Le Fort I osteotomy i.e., Classic Pterygomaxillary Dysjunction technique and Trimble technique and to know whether the dimensions of pterygomaxillary junction [determined preoperatively by computed tomography (CT) scan] have any influence on pterygomaxillary separation achieved during surgery. The study group consisted of eight South Indian patients with maxillary excess. A total of 16 sides were examined by CT. Preoperative CT was analyzed for all the patients. The thickness and width of the pterygomaxillary junction and the distance of the greater palatine canal from the pterygomaxillary junction was noted. Pterygomaxillary dysjunction was achieved by two techniques, the classic pterygomaxillary dysjunction technique (Group I) and Trimble technique (Group II). Patients were selected randomly and equally for both the techniques. Dysjunction was analyzed by postoperative CT. The average thickness of the pterygomaxillary junction on 16 sides was 4.5 ± 1.2 mm. Untoward pterygoid plate fractures occurred in Group I in 3 sides out of 8. In Trimble technique (Group II), no pterygoid plate fractures were noted. The average width of the pterygomaxillary junction was 7.8 ± 1.5 mm, distance of the greater palatine canal from pterygomaxillary junction was 7.4 ± 1.6 mm and the length of fusion of pterygomaxillary junction was 8.0 ± 1.9 mm. The Le Fort I osteotomy has become a standard procedure for correcting various dentofacial deformities. In an attempt to make Le Fort I osteotomy safer and avoid the problems associated with sectioning with an osteotome between the maxillary tuberosity and the pterygoid plates, Trimble suggested sectioning across the posterior aspect of the maxillary tuberosity itself. In our study, comparison between the classic pterygomaxillary dysjunction technique and the Trimble technique was made by using postoperative CT scan. It was found that unfavorable pterygoid plate fractures occurred only in dysjunction group and not in Trimble technique group. Preoperative CT scan assessment was done for all the patients to determine the dimension of the pterygomaxillary region. Preoperative CT scan proved to be helpful in not only determining the dimensions of the pterygomaxillary region but we also found out that thickness of the pterygomaxillary junction was an important parameter which may influence the separation at the pterygomaxillary region. No untoward fractures of the pterygoid plates were seen in Trimble technique (Group II) which makes it a safer technique than classic dysjunction technique. It was noted that pterygoid plate fractures occurred in patients in whom the thickness of the pterygomaxillary junction was <3.6 mm (preoperatively). Therefore, preoperative evaluation is important, on the basis of which we can decide upon the technique to be selected for safer and acceptable separation of pterygomaxillary region.

Time-resolved spectral characterization of ring cavity surface emitting and ridge-type distributed feedback quantum cascade lasers by step-scan FT-IR spectroscopy.

PubMed

Brandstetter, Markus; Genner, Andreas; Schwarzer, Clemens; Mujagic, Elvis; Strasser, Gottfried; Lendl, Bernhard

2014-02-10

We present the time-resolved comparison of pulsed 2nd order ring cavity surface emitting (RCSE) quantum cascade lasers (QCLs) and pulsed 1st order ridge-type distributed feedback (DFB) QCLs using a step-scan Fourier transform infrared (FT-IR) spectrometer. Laser devices were part of QCL arrays and fabricated from the same laser material. Required grating periods were adjusted to account for the grating order. The step-scan technique provided a spectral resolution of 0.1 cm(-1) and a time resolution of 2 ns. As a result, it was possible to gain information about the tuning behavior and potential mode-hops of the investigated lasers. Different cavity-lengths were compared, including 0.9 mm and 3.2 mm long ridge-type and 0.97 mm (circumference) ring-type cavities. RCSE QCLs were found to have improved emission properties in terms of line-stability, tuning rate and maximum emission time compared to ridge-type lasers.

Fluorescence Imaging Topography Scanning System for intraoperative multimodal imaging

PubMed Central

Quang, Tri T.; Kim, Hye-Yeong; Bao, Forrest Sheng; Papay, Francis A.; Edwards, W. Barry; Liu, Yang

2017-01-01

Fluorescence imaging is a powerful technique with diverse applications in intraoperative settings. Visualization of three dimensional (3D) structures and depth assessment of lesions, however, are oftentimes limited in planar fluorescence imaging systems. In this study, a novel Fluorescence Imaging Topography Scanning (FITS) system has been developed, which offers color reflectance imaging, fluorescence imaging and surface topography scanning capabilities. The system is compact and portable, and thus suitable for deployment in the operating room without disturbing the surgical flow. For system performance, parameters including near infrared fluorescence detection limit, contrast transfer functions and topography depth resolution were characterized. The developed system was tested in chicken tissues ex vivo with simulated tumors for intraoperative imaging. We subsequently conducted in vivo multimodal imaging of sentinel lymph nodes in mice using FITS and PET/CT. The PET/CT/optical multimodal images were co-registered and conveniently presented to users to guide surgeries. Our results show that the developed system can facilitate multimodal intraoperative imaging. PMID:28437441

Moths on the Flatbed Scanner: The Art of Joseph Scheer

PubMed Central

Buchmann, Stephen L.

2011-01-01

During the past decade a few artists and even fewer entomologists discovered flatbed scanning technology, using extreme resolution graphical arts scanners for acquiring high magnification digital images of plants, animals and inanimate objects. They are not just for trip receipts anymore. The special attributes of certain scanners, to image thick objects is discussed along with the technical features of the scanners including magnification, color depth and shadow detail. The work of pioneering scanner artist, Joseph Scheer from New York's Alfred University is highlighted. Representative flatbed-scanned images of moths are illustrated along with techniques to produce them. Collecting and preparing moths, and other objects, for scanning are described. Highlights of the Fulbright sabbatical year of professor Scheer in Arizona and Sonora, Mexico are presented, along with comments on moths in science, folklore, art and pop culture. The use of flatbed scanners is offered as a relatively new method for visualizing small objects while acquiring large files for creating archival inkjet prints for display and sale. PMID:26467835

1.56 Terahertz 2-frames per second standoff imaging

NASA Astrophysics Data System (ADS)

Goyette, Thomas M.; Dickinson, Jason C.; Linden, Kurt J.; Neal, William R.; Joseph, Cecil S.; Gorveatt, William J.; Waldman, Jerry; Giles, Robert; Nixon, William E.

2008-02-01

A Terahertz imaging system intended to demonstrate identification of objects concealed under clothing was designed, assembled, and tested. The system design was based on a 2.5 m standoff distance, with a capability of visualizing a 0.5 m by 0.5 m scene at an image rate of 2 frames per second. The system optical design consisted of a 1.56 THz laser beam, which was raster swept by a dual torsion mirror scanner. The beam was focused onto the scan subject by a stationary 50 cm-diameter focusing mirror. A heterodyne detection technique was used to down convert the backscattered signal. The system demonstrated a 1.5 cm spot resolution. Human subjects were scanned at a frame rate of 2 frames per second. Hidden metal objects were detected under a jacket worn by the human subject. A movie including data and video images was produced in 1.5 minutes scanning a human through 180° of azimuth angle at 0.7° increment.

Computer enhancement of radiographs

NASA Technical Reports Server (NTRS)

Dekaney, A.; Keane, J.; Desautels, J.

1973-01-01

Examination of three relevant noise processes and the image degradation associated with Marshall Space Flight Center's (MSFC) X-ray/scanning system was conducted for application to computer enhancement of radiographs using MSFC's digital filtering techniques. Graininess of type M, R single coat and R double coat X-ray films was quantified as a function of density level using root-mean-square (RMS) granularity. Quantum mottle (including film grain) was quantified as a function of the above film types, exposure level, specimen material and thickness, and film density using RMS granularity and power spectral density (PSD). For various neutral-density levels the scanning device used in digital conversion of radiographs was examined for noise characteristics which were quantified by RMS granularity and PSD. Image degradation of the entire pre-enhancement system (MG-150 X-ray device; film; and optronics scanner) was measured using edge targets to generate modulation transfer functions (MTF). The four parameters were examined as a function of scanning aperture sizes of approximately 12.5 25 and 50 microns.

Results from a Prototype Proton-CT Head Scanner

NASA Astrophysics Data System (ADS)

Johnson, R. P.; Bashkirov, V. A.; Coutrakon, G.; Giacometti, V.; Karbasi, P.; Karonis, N. T.; Ordoñez, C. E.; Pankuch, M.; Sadrozinski, H. F.-W.; Schubert, K. E.; Schulte, R. W.

We are exploring low-dose proton radiography and computed tomography (pCT) as techniques to improve the accuracy of proton treatment planning and to provide artifact-free images for verification and adaptive therapy at the time of treatment. Here we report on comprehensive beam test results with our prototype pCT head scanner. The detector system and data acquisition attain a sustained rate of more than a million protons individually measured per second, allowing a full CT scan to be completed in six minutes or less of beam time. In order to assess the performance of the scanner for proton radiography as well as computed tomography, we have performed numerous scans of phantoms at the Northwestern Medicine Chicago Proton Center including a custom phantom designed to assess the spatial resolution, a phantom to assess the measurement of relative stopping power, and a dosimetry phantom. Some images, performance, and dosimetry results from those phantom scans are presented together with a description of the instrument, the data acquisition system, and the calibration methods.

Laser Ultrasound Spectroscopy Scanning for 3D Printed Parts

DOE Office of Scientific and Technical Information (OSTI.GOV)

Brennan, Guendalyn Kendra

One of the challenges of additive manufacturing is quality control due to the possibility of unseen flaws in the final product. The current methods of inspection are lacking in detail, too slow for practical use, or unable to validate internal structure. This report examines the use of laser ultrasound spectroscopy in layer by layer scans of 3D printed parts as they are created. The result is fast and detailed quality control. An additional advantage of this method is the ability to cancel a print as soon as a defect is detected, therefore saving materials and time. This technique, though simplemore » in concept, has been a challenge to implement. I discuss tweaking the 3D printer configuration, and finding the optimal settings for laser scanning small parts made of ABS plastic, as well as the limits of how small of a detail the laser can detect. These settings include the frequency of the ultrasonic transducer, the speed of the laser, and the distance from the laser to the part.« less

Optical toolkits for in vivo deep tissue laser scanning microscopy: a primer

NASA Astrophysics Data System (ADS)

Lee, Woei Ming; McMenamin, Thomas; Li, Yongxiao

2018-06-01

Life at the microscale is animated and multifaceted. The impact of dynamic in vivo microscopy in small animals has opened up opportunities to peer into a multitude of biological processes at the cellular scale in their native microenvironments. Laser scanning microscopy (LSM) coupled with targeted fluorescent proteins has become an indispensable tool to enable dynamic imaging in vivo at high temporal and spatial resolutions. In the last few decades, the technique has been translated from imaging cells in thin samples to mapping cells in the thick biological tissue of living organisms. Here, we sought to provide a concise overview of the design considerations of a LSM that enables cellular and subcellular imaging in deep tissue. Individual components under review include: long working distance microscope objectives, laser scanning technologies, adaptive optics devices, beam shaping technologies and photon detectors, with an emphasis on more recent advances. The review will conclude with the latest innovations in automated optical microscopy, which would impact tracking and quantification of heterogeneous populations of cells in vivo.

Recent neuroimaging techniques in mild traumatic brain injury.

PubMed

Belanger, Heather G; Vanderploeg, Rodney D; Curtiss, Glenn; Warden, Deborah L

2007-01-01

Mild traumatic brain injury (TBI) is characterized by acute physiological changes that result in at least some acute cognitive difficulties and typically resolve by 3 months postinjury. Because the majority of mild TBI patients have normal structural magnetic resonance imaging (MRI)/computed tomography (CT) scans, there is increasing attention directed at finding objective physiological correlates of persistent cognitive and neuropsychiatric symptoms through experimental neuroimaging techniques. The authors review studies utilizing these techniques in patients with mild TBI; these techniques may provide more sensitive assessment of structural and functional abnormalities following mild TBI. Particular promise is evident with fMRI, PET, and SPECT scanning, as demonstrated by associations between brain activation and clinical outcomes.

Technical Note: A Time-Dependent I(sub 0) Correction for Solar Occultation Instruments

NASA Technical Reports Server (NTRS)

Burton, Sharon P.; Thomason, Larry W.; Zawodny, Joseph M.

2009-01-01

Solar occultation has proven to be a reliable technique for the measurement of atmospheric constituents in the stratosphere. NASA's Stratospheric Aerosol and Gas Experiments (SAGE, SAGE II, and SAGE III) together have provided over 25 years of quality solar occultation data, a data record which has been an important resource for the scientific exploration of atmospheric composition and climate change. Herein, we describe an improvement to the processing of SAGE data that corrects for a previously uncorrected short-term timedependence in the calibration function. The variability relates to the apparent rotation of the scanning track with respect to the face of the sun due to the motion of the satellite. Correcting for this effect results in a decrease in the measurement noise in the Level 1 line-of-sight optical depth measurements of approximately 40% in the middle and upper stratospheric SAGE II and III where it has been applied. The technique is potentially useful for any scanning solar occultation instrument, and suggests further improvement for future occultation measurements if a full disk imaging system can be included.

Nanomaterial datasets to advance tomography in scanning transmission electron microscopy

DOE PAGES

Levin, Barnaby D. A.; Padgett, Elliot; Chen, Chien-Chun; ...

2016-06-07

Electron tomography in materials science has flourished with the demand to characterize nanoscale materials in three dimensions (3D). Access to experimental data is vital for developing and validating reconstruction methods that improve resolution and reduce radiation dose requirements. This work presents five high-quality scanning transmission electron microscope (STEM) tomography datasets in order to address the critical need for open access data in this field. The datasets represent the current limits of experimental technique, are of high quality, and contain materials with structural complexity. Included are tomographic series of a hyperbranched Co 2 P nanocrystal, platinum nanoparticles on a carbonmore » nanofibre imaged over the complete 180° tilt range, a platinum nanoparticle and a tungsten needle both imaged at atomic resolution by equal slope tomography, and a through-focal tilt series of PtCu nanoparticles. A volumetric reconstruction from every dataset is provided for comparison and development of post-processing and visualization techniques. Researchers interested in creating novel data processing and reconstruction algorithms will now have access to state of the art experimental test data.« less

Optically sectioned in vivo imaging with speckle illumination HiLo microscopy

PubMed Central

Lim, Daryl; Ford, Tim N.; Chu, Kengyeh K.; Mertz, Jerome

2011-01-01

We present a simple wide-field imaging technique, called HiLo microscopy, that is capable of producing optically sectioned images in real time, comparable in quality to confocal laser scanning microscopy. The technique is based on the fusion of two raw images, one acquired with speckle illumination and another with standard uniform illumination. The fusion can be numerically adjusted, using a single parameter, to produce optically sectioned images of varying thicknesses with the same raw data. Direct comparison between our HiLo microscope and a commercial confocal laser scanning microscope is made on the basis of sectioning strength and imaging performance. Specifically, we show that HiLo and confocal 3-D imaging of a GFP-labeled mouse brain hippocampus are comparable in quality. Moreover, HiLo microscopy is capable of faster, near video rate imaging over larger fields of view than attainable with standard confocal microscopes. The goal of this paper is to advertise the simplicity, robustness, and versatility of HiLo microscopy, which we highlight with in vivo imaging of common model organisms including planaria, C. elegans, and zebrafish. PMID:21280920

Optically sectioned in vivo imaging with speckle illumination HiLo microscopy.

PubMed

Lim, Daryl; Ford, Tim N; Chu, Kengyeh K; Mertz, Jerome

2011-01-01

We present a simple wide-field imaging technique, called HiLo microscopy, that is capable of producing optically sectioned images in real time, comparable in quality to confocal laser scanning microscopy. The technique is based on the fusion of two raw images, one acquired with speckle illumination and another with standard uniform illumination. The fusion can be numerically adjusted, using a single parameter, to produce optically sectioned images of varying thicknesses with the same raw data. Direct comparison between our HiLo microscope and a commercial confocal laser scanning microscope is made on the basis of sectioning strength and imaging performance. Specifically, we show that HiLo and confocal 3-D imaging of a GFP-labeled mouse brain hippocampus are comparable in quality. Moreover, HiLo microscopy is capable of faster, near video rate imaging over larger fields of view than attainable with standard confocal microscopes. The goal of this paper is to advertise the simplicity, robustness, and versatility of HiLo microscopy, which we highlight with in vivo imaging of common model organisms including planaria, C. elegans, and zebrafish.

Optically sectioned in vivo imaging with speckle illumination HiLo microscopy

NASA Astrophysics Data System (ADS)

Lim, Daryl; Ford, Tim N.; Chu, Kengyeh K.; Mertz, Jerome

2011-01-01

We present a simple wide-field imaging technique, called HiLo microscopy, that is capable of producing optically sectioned images in real time, comparable in quality to confocal laser scanning microscopy. The technique is based on the fusion of two raw images, one acquired with speckle illumination and another with standard uniform illumination. The fusion can be numerically adjusted, using a single parameter, to produce optically sectioned images of varying thicknesses with the same raw data. Direct comparison between our HiLo microscope and a commercial confocal laser scanning microscope is made on the basis of sectioning strength and imaging performance. Specifically, we show that HiLo and confocal 3-D imaging of a GFP-labeled mouse brain hippocampus are comparable in quality. Moreover, HiLo microscopy is capable of faster, near video rate imaging over larger fields of view than attainable with standard confocal microscopes. The goal of this paper is to advertise the simplicity, robustness, and versatility of HiLo microscopy, which we highlight with in vivo imaging of common model organisms including planaria, C. elegans, and zebrafish.

Digital Workflow for the Conservation of Bahrain Built Heritage: the Sheik Isa Bin ALI House

NASA Astrophysics Data System (ADS)

Barazzetti, L.; Mezzino, D.; Santana Quintero, M.

2017-08-01

Currently, the commercial market offers several tools for digital documentation of historic sites and buildings. Photogrammetry and laser scanning play a fundamental role in the acquisition of metric information, which is then processed to generate reliable records particularly useful also in the built heritage conservation field. Although potentially very fast and accurate, such techniques require expert operators to produce reliable results, especially in the case of complex and large sites. The aim of this paper is to present the digital workflow developed for data acquisition and processing of the Shaikh Isa Bin Ali house in Muharraq, Bahrain. This historic structure is an outstanding example of Bahrain architecture as well as tangible memory of the country history, with strong connotations in the Bahrain cultural identity. The building has been documented employing several digital techniques, including: aerial (drone) and terrestrial photogrammetry, rectifying photography, total station and laser scanning. The documentation project has been developed for the Bahrain Authority for Culture and Antiquities (BACA) by a multidisciplinary team of experts from Carleton Immersive Media Studio (CIMS, Carleton University, Canada) and Gicarus Lab (Politecnico di Milano, Italy).

Complex Archaeological Prospection Using Combination of Non-destructive Techniques

NASA Astrophysics Data System (ADS)

Faltýnová, M.; Pavelka, K.; Nový, P.; Šedina, J.

2015-08-01

This article describes the use of a combination of non-destructive techniques for the complex documentation of a fabulous historical site called Devil's Furrow, an unusual linear formation lying in the landscape of central Bohemia. In spite of many efforts towards interpretation of the formation, its original form and purpose have not yet been explained in a satisfactory manner. The study focuses on the northern part of the furrow which appears to be a dissimilar element within the scope of the whole Devil's Furrow. This article presents detailed description of relics of the formation based on historical map searches and modern investigation methods including airborne laser scanning, aerial photogrammetry (based on airplane and RPAS) and ground-penetrating radar. Airborne laser scanning data and aerial orthoimages acquired by the Czech Office for Surveying, Mapping and Cadastre were used. Other measurements were conducted by our laboratory. Data acquired by various methods provide sufficient information to determine the probable original shape of the formation and proves explicitly the anthropological origin of the northern part of the formation (around village Lipany).

Nanomaterial datasets to advance tomography in scanning transmission electron microscopy.

PubMed

Levin, Barnaby D A; Padgett, Elliot; Chen, Chien-Chun; Scott, M C; Xu, Rui; Theis, Wolfgang; Jiang, Yi; Yang, Yongsoo; Ophus, Colin; Zhang, Haitao; Ha, Don-Hyung; Wang, Deli; Yu, Yingchao; Abruña, Hector D; Robinson, Richard D; Ercius, Peter; Kourkoutis, Lena F; Miao, Jianwei; Muller, David A; Hovden, Robert

2016-06-07

Electron tomography in materials science has flourished with the demand to characterize nanoscale materials in three dimensions (3D). Access to experimental data is vital for developing and validating reconstruction methods that improve resolution and reduce radiation dose requirements. This work presents five high-quality scanning transmission electron microscope (STEM) tomography datasets in order to address the critical need for open access data in this field. The datasets represent the current limits of experimental technique, are of high quality, and contain materials with structural complexity. Included are tomographic series of a hyperbranched Co2P nanocrystal, platinum nanoparticles on a carbon nanofibre imaged over the complete 180° tilt range, a platinum nanoparticle and a tungsten needle both imaged at atomic resolution by equal slope tomography, and a through-focal tilt series of PtCu nanoparticles. A volumetric reconstruction from every dataset is provided for comparison and development of post-processing and visualization techniques. Researchers interested in creating novel data processing and reconstruction algorithms will now have access to state of the art experimental test data.

Nanomaterial datasets to advance tomography in scanning transmission electron microscopy

PubMed Central

Levin, Barnaby D.A.; Padgett, Elliot; Chen, Chien-Chun; Scott, M.C.; Xu, Rui; Theis, Wolfgang; Jiang, Yi; Yang, Yongsoo; Ophus, Colin; Zhang, Haitao; Ha, Don-Hyung; Wang, Deli; Yu, Yingchao; Abruña, Hector D.; Robinson, Richard D.; Ercius, Peter; Kourkoutis, Lena F.; Miao, Jianwei; Muller, David A.; Hovden, Robert

2016-01-01

Electron tomography in materials science has flourished with the demand to characterize nanoscale materials in three dimensions (3D). Access to experimental data is vital for developing and validating reconstruction methods that improve resolution and reduce radiation dose requirements. This work presents five high-quality scanning transmission electron microscope (STEM) tomography datasets in order to address the critical need for open access data in this field. The datasets represent the current limits of experimental technique, are of high quality, and contain materials with structural complexity. Included are tomographic series of a hyperbranched Co2P nanocrystal, platinum nanoparticles on a carbon nanofibre imaged over the complete 180° tilt range, a platinum nanoparticle and a tungsten needle both imaged at atomic resolution by equal slope tomography, and a through-focal tilt series of PtCu nanoparticles. A volumetric reconstruction from every dataset is provided for comparison and development of post-processing and visualization techniques. Researchers interested in creating novel data processing and reconstruction algorithms will now have access to state of the art experimental test data. PMID:27272459

WE-D-BRB-00: Basics of Proton Therapy

DOE Office of Scientific and Technical Information (OSTI.GOV)

NONE

The goal of this session is to review the physics of proton therapy, treatment planning techniques, and the use of volumetric imaging in proton therapy. The course material covers the physics of proton interaction with matter and physical characteristics of clinical proton beams. It will provide information on proton delivery systems and beam delivery techniques for double scattering (DS), uniform scanning (US), and pencil beam scanning (PBS). The session covers the treatment planning strategies used in DS, US, and PBS for various anatomical sites, methods to address uncertainties in proton therapy and uncertainty mitigation to generate robust treatment plans. Itmore » introduces the audience to the current status of image guided proton therapy and clinical applications of CBCT for proton therapy. It outlines the importance of volumetric imaging in proton therapy. Learning Objectives: Gain knowledge in proton therapy physics, and treatment planning for proton therapy including intensity modulated proton therapy. The current state of volumetric image guidance equipment in proton therapy. Clinical applications of CBCT and its advantage over orthogonal imaging for proton therapy. B. Teo, B.K Teo had received travel funds from IBA in 2015.« less

Non-contact optoacoustic imaging by raster scanning a piezoelectric air-coupled transducer

NASA Astrophysics Data System (ADS)

Deán-Ben, X. Luís.; Pang, Genny A.; Montero de Espinosa, Francisco; Razansky, Daniel

2016-03-01

Optoacoustic techniques rely on ultrasound transmission between optical absorbers within tissues and the measurement location. Much like in echography, commonly used piezoelectric transducers require either direct contact with the tissue or through a liquid coupling medium. The contact nature of this detection approach then represents a disadvantage of standard optoacoustic systems with respect to other imaging modalities (including optical techniques) in applications where non-contact imaging is needed, e.g. in open surgeries or when burns or other lesions are present in the skin. Herein, non-contact optoacoustic imaging using raster-scanning of a spherically-focused piezoelectric air-coupled ultrasound transducer is demonstrated. When employing laser fluence levels not exceeding the maximal permissible human exposure, it is shown possible to attain detectable signals from objects as small as 1 mm having absorption properties representative of blood at near-infrared wavelengths with a relatively low number of averages. Optoacoustic images from vessel-mimicking tubes embedded in an agar phantom are further showcased. The initial results indicate that the air-coupled ultrasound detection approach can be potentially made suitable for non-contact biomedical imaging with optoacoustics.

Radiological risks of neutron interrogation of food.

PubMed

Albright, S; Seviour, R

2015-09-01

In recent years there has been growing interest in the use of neutron scanning techniques for security. Neutron techniques with a range of energy spectra including thermal, white and fast neutrons have been shown to work in different scenarios. As international interest in neutron scanning increases the risk of activating cargo, especially foodstuffs must be considered. There has been a limited amount of research into the activation of foods by neutron beams and we have sought to improve the amount of information available. In this paper we show that for three important metrics; activity, ingestion dose and Time to Background there is a strong dependence on the food being irradiated and a weak dependence on the energy of irradiation. Previous studies into activation used results based on irradiation of pharmaceuticals as the basis for research into activation of food. The earlier work reports that (24)Na production is the dominant threat which motivated the search for (24)Na(n,γ)(24)Na in highly salted foods. We show that (42)K can be more significant than (24)Na in low sodium foods such as Bananas and Potatoes.

Fast-scan Cyclic Voltammetry for the Characterization of Rapid Adenosine Release.

PubMed

Nguyen, Michael D; Venton, B Jill

2015-01-01

Adenosine is a signaling molecule and downstream product of ATP that acts as a neuromodulator. Adenosine regulates physiological processes, such as neurotransmission and blood flow, on a time scale of minutes to hours. Recent developments in electrochemical techniques, including fast-scan cyclic voltammetry (FSCV), have allowed direct detection of adenosine with sub-second temporal resolution. FSCV studies have revealed a novel mode of rapid signaling that lasts only a few seconds. This rapid release of adenosine can be evoked by electrical or mechanical stimulations or it can be observed spontaneously without stimulation. Adenosine signaling on this time scale is activity dependent; however, the mode of release is not fully understood. Rapid adenosine release modulates oxygen levels and evoked dopamine release, indicating that adenosine may have a rapid modulatory role. In this review, we outline how FSCV can be used to detect adenosine release, compare FSCV with other techniques used to measure adenosine, and present an overview of adenosine signaling that has been characterized using FSCV. These studies point to a rapid mode of adenosine modulation, whose mechanism and function will continue to be characterized in the future.

The study of frequency-scan photothermal reflectance technique for thermal diffusivity measurement

DOE PAGES

Hua, Zilong; Ban, Heng; Hurley, David H.

2015-05-05

A frequency scan photothermal reflectance technique to measure thermal diffusivity of bulk samples is studied in this manuscript. Similar to general photothermal reflectance methods, an intensity-modulated heating laser and a constant intensity probe laser are used to determine the surface temperature response under sinusoidal heating. The approach involves fixing the distance between the heating and probe laser spots, recording the phase lag of reflected probe laser intensity with respect to the heating laser frequency modulation, and extracting thermal diffusivity using the phase lag – (frequency) 1/2 relation. The experimental validation is performed on three samples (SiO 2, CaF 2 andmore » Ge), which have a wide range of thermal diffusivities. The measured thermal diffusivity values agree closely with literature values. Lastly, compared to the commonly used spatial scan method, the experimental setup and operation of the frequency scan method are simplified, and the uncertainty level is equal to or smaller than that of the spatial scan method.« less

The study of frequency-scan photothermal reflectance technique for thermal diffusivity measurement

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hua, Zilong; Ban, Heng; Hurley, David H.

A frequency scan photothermal reflectance technique to measure thermal diffusivity of bulk samples is studied in this manuscript. Similar to general photothermal reflectance methods, an intensity-modulated heating laser and a constant intensity probe laser are used to determine the surface temperature response under sinusoidal heating. The approach involves fixing the distance between the heating and probe laser spots, recording the phase lag of reflected probe laser intensity with respect to the heating laser frequency modulation, and extracting thermal diffusivity using the phase lag – (frequency) 1/2 relation. The experimental validation is performed on three samples (SiO 2, CaF 2 andmore » Ge), which have a wide range of thermal diffusivities. The measured thermal diffusivity values agree closely with literature values. Lastly, compared to the commonly used spatial scan method, the experimental setup and operation of the frequency scan method are simplified, and the uncertainty level is equal to or smaller than that of the spatial scan method.« less

Standardization of Analysis Sets for Reporting Results from ADNI MRI Data

PubMed Central

Wyman, Bradley T.; Harvey, Danielle J.; Crawford, Karen; Bernstein, Matt A.; Carmichael, Owen; Cole, Patricia E.; Crane, Paul; DeCarli, Charles; Fox, Nick C.; Gunter, Jeffrey L.; Hill, Derek; Killiany, Ronald J.; Pachai, Chahin; Schwarz, Adam J.; Schuff, Norbert; Senjem, Matthew L.; Suhy, Joyce; Thompson, Paul M.; Weiner, Michael; Jack, Clifford R.

2013-01-01

The ADNI 3D T1-weighted MRI acquisitions provide a rich dataset for developing and testing analysis techniques for extracting structural endpoints. To promote greater rigor in analysis and meaningful comparison of different algorithms, the ADNI MRI Core has created standardized analysis sets of data comprising scans that met minimum quality control requirements. We encourage researchers to test and report their techniques against these data. Standard analysis sets of volumetric scans from ADNI-1 have been created, comprising: screening visits, 1 year completers (subjects who all have screening, 6 and 12 month scans), two year annual completers (screening, 1, and 2 year scans), two year completers (screening, 6 months, 1 year, 18 months (MCI only) and 2 years) and complete visits (screening, 6 months, 1 year, 18 months (MCI only), 2, and 3 year (normal and MCI only) scans). As the ADNI-GO/ADNI-2 data becomes available, updated standard analysis sets will be posted regularly. PMID:23110865

Identifying irregularly shaped crime hot-spots using a multiobjective evolutionary algorithm

NASA Astrophysics Data System (ADS)

Wu, Xiaolan; Grubesic, Tony H.

2010-12-01

Spatial cluster detection techniques are widely used in criminology, geography, epidemiology, and other fields. In particular, spatial scan statistics are popular and efficient techniques for detecting areas of elevated crime or disease events. The majority of spatial scan approaches attempt to delineate geographic zones by evaluating the significance of clusters using likelihood ratio statistics tested with the Poisson distribution. While this can be effective, many scan statistics give preference to circular clusters, diminishing their ability to identify elongated and/or irregular shaped clusters. Although adjusting the shape of the scan window can mitigate some of these problems, both the significance of irregular clusters and their spatial structure must be accounted for in a meaningful way. This paper utilizes a multiobjective evolutionary algorithm to find clusters with maximum significance while quantitatively tracking their geographic structure. Crime data for the city of Cincinnati are utilized to demonstrate the advantages of the new approach and highlight its benefits versus more traditional scan statistics.

Transfer doping of single isolated nanodiamonds, studied by scanning probe microscopy techniques.

PubMed

Bolker, Asaf; Saguy, Cecile; Kalish, Rafi

2014-09-26

The transfer doping of diamond surfaces has been applied in various novel two-dimensional electronic devices. Its extension to nanodiamonds (ND) is essential for ND-based applications in many fields. In particular, understanding the influence of the crystallite size on transfer doping is desirable. Here, we report the results of a detailed study of the electronic energetic band structure of single, isolated transfer-doped nanodiamonds with nanometric resolution using a combination of scanning tunneling spectroscopy and Kelvin force microscopy measurements. The results show how the band gap, the valence band maximum, the electron affinity and the work function all depend on the ND's size and nanoparticle surface properties. The present analysis, which combines information from both scanning tunneling spectroscopy and Kelvin force microscopy, should be applicable to any nanoparticle or surface that can be measured with scanning probe techniques.

In vivo microscopy of the mouse brain using multiphoton laser scanning techniques

NASA Astrophysics Data System (ADS)

Yoder, Elizabeth J.

2002-06-01

The use of multiphoton microscopy for imaging mouse brain in vivo offers several advantages and poses several challenges. This tutorial begins by briefly comparing multiphoton microscopy with other imaging modalities used to visualize the brain and its activity. Next, an overview of the techniques for introducing fluorescence into whole animals to generate contrast for in vivo microscopy using two-photon excitation is presented. Two different schemes of surgically preparing mice for brain imaging with multiphoton microscopy are reviewed. Then, several issues and problems with in vivo microscopy - including motion artifact, respiratory and cardiac rhythms, maintenance of animal health, anesthesia, and the use of fiducial markers - are discussed. Finally, examples of how these techniques have been applied to visualize the cerebral vasculature and its response to hypercapnic stimulation are provided.

Document Examination: Applications of Image Processing Systems.

PubMed

Kopainsky, B

1989-12-01

Dealing with images is a familiar business for an expert in questioned documents: microscopic, photographic, infrared, and other optical techniques generate images containing the information he or she is looking for. A recent method for extracting most of this information is digital image processing, ranging from the simple contrast and contour enhancement to the advanced restoration of blurred texts. When combined with a sophisticated physical imaging system, an image pricessing system has proven to be a powerful and fast tool for routine non-destructive scanning of suspect documents. This article reviews frequent applications, comprising techniques to increase legibility, two-dimensional spectroscopy (ink discrimination, alterations, erased entries, etc.), comparison techniques (stamps, typescript letters, photo substitution), and densitometry. Computerized comparison of handwriting is not included. Copyright © 1989 Central Police University.

Facility for low-temperature spin-polarized-scanning tunneling microscopy studies of magnetic/spintronic materials prepared in situ by nitride molecular beam epitaxy.

PubMed

Lin, Wenzhi; Foley, Andrew; Alam, Khan; Wang, Kangkang; Liu, Yinghao; Chen, Tianjiao; Pak, Jeongihm; Smith, Arthur R

2014-04-01

Based on the interest in, as well as exciting outlook for, nitride semiconductor based structures with regard to electronic, optoelectronic, and spintronic applications, it is compelling to investigate these systems using the powerful technique of spin-polarized scanning tunneling microscopy (STM), a technique capable of achieving magnetic resolution down to the atomic scale. However, the delicate surfaces of these materials are easily corrupted by in-air transfers, making it unfeasible to study them in stand-alone ultra-high vacuum STM facilities. Therefore, we have carried out the development of a hybrid system including a nitrogen plasma assisted molecular beam epitaxy/pulsed laser epitaxy facility for sample growth combined with a low-temperature, spin-polarized scanning tunneling microscope system. The custom-designed molecular beam epitaxy growth system supports up to eight sources, including up to seven effusion cells plus a radio frequency nitrogen plasma source, for epitaxially growing a variety of materials, such as nitride semiconductors, magnetic materials, and their hetero-structures, and also incorporating in situ reflection high energy electron diffraction. The growth system also enables integration of pulsed laser epitaxy. The STM unit has a modular design, consisting of an upper body and a lower body. The upper body contains the coarse approach mechanism and the scanner unit, while the lower body accepts molecular beam epitaxy grown samples using compression springs and sample skis. The design of the system employs two stages of vibration isolation as well as a layer of acoustic noise isolation in order to reduce noise during STM measurements. This isolation allows the system to effectively acquire STM data in a typical lab space, which during its construction had no special and highly costly elements included, (such as isolated slabs) which would lower the environmental noise. The design further enables tip exchange and tip coating without breaking vacuum, and convenient visual access to the sample and tip inside a superconducting magnet cryostat. A sample/tip handling system is optimized for both the molecular beam epitaxy growth system and the scanning tunneling microscope system. The sample/tip handing system enables in situ STM studies on epitaxially grown samples, and tip exchange in the superconducting magnet cryostat. The hybrid molecular beam epitaxy and low temperature scanning tunneling microscopy system is capable of growing semiconductor-based hetero-structures with controlled accuracy down to a single atomic-layer and imaging them down to atomic resolution.

Infrared radiometer for the Pioneer Venus orbiter. I - Instrument description

NASA Technical Reports Server (NTRS)

Taylor, F. W.; Vescelus, F. E.; Locke, J. R.; Beer, R.; Foster, G. T.; Forney, P. B.; Houghton, J. T.; Delderfield, J.; Schofield, J. T.

1979-01-01

A ten-channel IR radiometer for the Pioneer Venus orbiter is described. The experimental techniques used and the design of the instrumentation by which they were implemented are considered. Emphasis is placed on temperature sounding, limb sounding, limb darkening, zenith scanning, cloud top temperature, spectral albedo and water vapor measurements. Instrumentation description is also given including optics, detectors, and electronics. Attention is given to data acquisition and handling, calibration, and in-flight performance.

HANFORD WASTE MINERALOGY REFERENCE REPORT

DOE Office of Scientific and Technical Information (OSTI.GOV)

DISSELKAMP RS

2010-06-29

This report lists the observed mineral phases present in the Hanford tanks. This task was accomplished by performing a review of numerous reports that used experimental techniques including, but not limited to: x-ray diffraction, polarized light microscopy, scanning electron microscopy, transmission electron microscopy, energy dispersive spectroscopy, electron energy loss spectroscopy, and particle size distribution analyses. This report contains tables that can be used as a quick reference to identify the crystal phases observed in Hanford waste.

HANFORD WASTE MINEROLOGY REFERENCE REPORT

DOE Office of Scientific and Technical Information (OSTI.GOV)

DISSELKAMP RS

2010-06-18

This report lists the observed mineral phase phases present in the Hanford tanks. This task was accomplished by performing a review of numerous reports using experimental techniques including, but not limited to: x-ray diffraction, polarized light microscopy, scanning electron microscopy, transmission electron microscopy, energy dispersive spectroscopy, electron energy loss spectroscopy, and particle size distribution analyses. This report contains tables that can be used as a quick reference to identify the crystal phases present observed in Hanford waste.

Doppler lidar wind measurement on Eos

NASA Technical Reports Server (NTRS)

Fitzjarrald, D.; Bilbro, J.; Beranek, R.; Mabry, J.

1985-01-01

A polar-orbiting platform segment of the Earth Observing System (EOS) could carry a CO2-laser based Doppler lidar for recording global wind profiles. Development goals would include the manufacture of a 10 J laser with a 2 yr operational life, space-rating the optics and associated software, and the definition of models for global aerosol distributions. Techniques will be needed for optimal scanning and generating computer simulations which will provide adequately accurate weather predictions.

Re-scan confocal microscopy: scanning twice for better resolution.

PubMed

De Luca, Giulia M R; Breedijk, Ronald M P; Brandt, Rick A J; Zeelenberg, Christiaan H C; de Jong, Babette E; Timmermans, Wendy; Azar, Leila Nahidi; Hoebe, Ron A; Stallinga, Sjoerd; Manders, Erik M M

2013-01-01

We present a new super-resolution technique, Re-scan Confocal Microscopy (RCM), based on standard confocal microscopy extended with an optical (re-scanning) unit that projects the image directly on a CCD-camera. This new microscope has improved lateral resolution and strongly improved sensitivity while maintaining the sectioning capability of a standard confocal microscope. This simple technology is typically useful for biological applications where the combination high-resolution and high-sensitivity is required.

Ultra-wide-band 3D microwave imaging scanner for the detection of concealed weapons

NASA Astrophysics Data System (ADS)

Rezgui, Nacer-Ddine; Andrews, David A.; Bowring, Nicholas J.

2015-10-01

The threat of concealed weapons, explosives and contraband in footwear, bags and suitcases has led to the development of new devices, which can be deployed for security screening. To address known deficiencies of metal detectors and x-rays, an UWB 3D microwave imaging scanning apparatus using FMCW stepped frequency working in the K and Q bands and with a planar scanning geometry based on an x y stage, has been developed to screen suspicious luggage and footwear. To obtain microwave images of the concealed weapons, the targets are placed above the platform and the single transceiver horn antenna attached to the x y stage is moved mechanically to perform a raster scan to create a 2D synthetic aperture array. The S11 reflection signal of the transmitted sweep frequency from the target is acquired by a VNA in synchronism with each position step. To enhance and filter from clutter and noise the raw data and to obtain the 2D and 3D microwave images of the concealed weapons or explosives, data processing techniques are applied to the acquired signals. These techniques include background subtraction, Inverse Fast Fourier Transform (IFFT), thresholding, filtering by gating and windowing and deconvolving with the transfer function of the system using a reference target. To focus the 3D reconstructed microwave image of the target in range and across the x y aperture without using focusing elements, 3D Synthetic Aperture Radar (SAR) techniques are applied to the post-processed data. The K and Q bands, between 15 to 40 GHz, show good transmission through clothing and dielectric materials found in luggage and footwear. A description of the system, algorithms and some results with replica guns and a comparison of microwave images obtained by IFFT, 2D and 3D SAR techniques are presented.

Effects of Patellofemoral Taping on Patellofemoral Joint Alignment and Contact Area During Weight Bearing.

PubMed

Ho, Kai-Yu; Epstein, Ryan; Garcia, Ron; Riley, Nicole; Lee, Szu-Ping

2017-02-01

Study Design Controlled laboratory study. Background Although it has been theorized that patellofemoral joint (PFJ) taping can correct patellar malalignment, the effects of PFJ taping techniques on patellar alignment and contact area have not yet been studied during weight bearing. Objective To examine the effects of 2 taping approaches (Kinesio and McConnell) on PFJ alignment and contact area. Methods Fourteen female subjects with patellofemoral pain and PFJ malalignment participated. Each subject underwent a pretaping magnetic resonance imaging (MRI) scan session and 2 MRI scan sessions after the application of the 2 taping techniques, which aimed to correct lateral patellar displacement. Subjects were asked to report their pain level prior to each scan session. During MRI assessment, subjects were loaded with 25% of body weight on their involved/more symptomatic leg at 0°, 20°, and 40° of knee flexion. The outcome measures included patellar lateral displacement (bisect-offset [BSO] index), mediolateral patellar tilt angle, patellar height (Insall-Salvati ratio), contact area, and pain. Patellofemoral joint alignment and contact area were compared among the 3 conditions (no tape, Kinesio, and McConnell) at 3 knee angles using a 2-factor, repeated-measures analysis of variance. Pain was compared among the 3 conditions using the Friedman test and post hoc Wilcoxon signed-rank tests. Results Our data did not reveal any significant effects of either McConnell or Kinesio taping on the BSO index, patellar tilt angle, Insall-Salvati ratio, or contact area across the 3 knee angles, whereas knee angle had a significant effect on the BSO index and contact area. A reduction in pain was observed after the application of the Kinesio taping technique. Conclusion In a weight-bearing condition, this preliminary study did not support the use of PFJ taping as a medial correction technique to alter the PFJ contact area or alignment of the patella. J Orthop Sports Phys Ther 2017;47(2):115-123. doi:10.2519/jospt.2017.6936.

Diffusion length measurement using the scanning electron microscope. [for silicon solar cell

NASA Technical Reports Server (NTRS)

Weizer, V. G.

1975-01-01

The present work describes a measuring technique employing the scanning electron microscope in which values of the true bulk diffusion length are obtained. It is shown that surface recombination effects can be eliminated through application of highly doped surface field layers. The effects of high injection level and low-high junction current generation are investigated. Results obtained with this technique are compared to those obtained by a penetrating radiation (X-ray) method, and a close agreement is found. The SEM technique is limited to cells that contain a back surface field layer.

[Technological innovations in radiation oncology require specific quality controls].

PubMed

Lenaerts, E; Mathot, M

2014-01-01

During the last decade, the field of radiotherapy has benefited from major technological innovations and continuously improving treatment efficacy, comfort and safety of patients. This mainly concerns the imaging techniques that allow 4D CT scan recording the respiratory phases, on-board imaging on linear accelerators that ensure perfect positioning of the patient for treatment and irradiation techniques that reduce very significantly the duration of treatment sessions without compromising quality of the treatment plan, including IMRT (Intensity Modulated Radiation Therapy) and VMAT (Volumetric Modulated Arc therapy). In this context of rapid technological change, it is the responsibility of medical physicists to regularly and precisely monitor the perfect functioning of new techniques to ensure patient safety. This requires the use of specific quality control equipment best suited to these new techniques. We will briefly describe the measurement system Delta4 used to control individualized treatment plan for each patient treated with VMAT technology.

The Characterization of Biosignatures in Caves Using an Instrument Suite

NASA Astrophysics Data System (ADS)

Uckert, Kyle; Chanover, Nancy J.; Getty, Stephanie; Voelz, David G.; Brinckerhoff, William B.; McMillan, Nancy; Xiao, Xifeng; Boston, Penelope J.; Li, Xiang; McAdam, Amy; Glenar, David A.; Chavez, Arriana

2017-12-01

The search for life and habitable environments on other Solar System bodies is a major motivator for planetary exploration. Due to the difficulty and significance of detecting extant or extinct extraterrestrial life in situ, several independent measurements from multiple instrument techniques will bolster the community's confidence in making any such claim. We demonstrate the detection of subsurface biosignatures using a suite of instrument techniques including IR reflectance spectroscopy, laser-induced breakdown spectroscopy, and scanning electron microscopy/energy dispersive X-ray spectroscopy. We focus our measurements on subterranean calcium carbonate field samples, whose biosignatures are analogous to those that might be expected on some high-interest astrobiology targets. In this work, we discuss the feasibility and advantages of using each of the aforementioned instrument techniques for the in situ search for biosignatures and present results on the autonomous characterization of biosignatures using multivariate statistical analysis techniques.

Measurements and Diagnostics of Diamond Films and Coatings

NASA Technical Reports Server (NTRS)

Miyoshi, Kazuhisa; Wu, Richard L. C.

1999-01-01

The commercial potential of chemical-vapor-deposited (CVD) diamond films has been established and a number of applications have been identified through university, industry, and government research studies. This paper discusses the methodologies used for property measurement and diagnostic of CVD diamond films and coatings. Measurement and diagnostic techniques studied include scanning electron microscopy, transmission electron microscopy, atomic force microscopy, stylus profilometry, x-ray diffraction, electron diffraction, Raman spectroscopy, Rutherford backscattering, elastic recoil spectroscopy, and friction examination. Each measurement and diagnostic technique provides unique information. A combination of techniques can provide the technical information required to understand the quality and properties of CVD diamond films, which are important to their application in specific component systems and environments. In this study the combination of measurement and diagnostic techniques was successfully applied to correlate deposition parameters and resultant diamond film composition, crystallinity, grain size, surface roughness, and coefficient of friction.

The Characterization of Biosignatures in Caves Using an Instrument Suite.

PubMed

Uckert, Kyle; Chanover, Nancy J; Getty, Stephanie; Voelz, David G; Brinckerhoff, William B; McMillan, Nancy; Xiao, Xifeng; Boston, Penelope J; Li, Xiang; McAdam, Amy; Glenar, David A; Chavez, Arriana

2017-12-01

The search for life and habitable environments on other Solar System bodies is a major motivator for planetary exploration. Due to the difficulty and significance of detecting extant or extinct extraterrestrial life in situ, several independent measurements from multiple instrument techniques will bolster the community's confidence in making any such claim. We demonstrate the detection of subsurface biosignatures using a suite of instrument techniques including IR reflectance spectroscopy, laser-induced breakdown spectroscopy, and scanning electron microscopy/energy dispersive X-ray spectroscopy. We focus our measurements on subterranean calcium carbonate field samples, whose biosignatures are analogous to those that might be expected on some high-interest astrobiology targets. In this work, we discuss the feasibility and advantages of using each of the aforementioned instrument techniques for the in situ search for biosignatures and present results on the autonomous characterization of biosignatures using multivariate statistical analysis techniques. Key Words: Biosignature suites-Caves-Mars-Life detection. Astrobiology 17, 1203-1218.

SEM visualization of glycosylated surface molecules using lectin-coated microspheres

NASA Technical Reports Server (NTRS)

Duke, J.; Janer, L.; Campbell, M.

1985-01-01

There are several techniques currently used to localize glycosylated surface molecules by scanning electron microscopy (Grinnell, 1980; Molday, 1976; Linthicum and Sell, 1975; Nicolson, 1974; Lo Buglio, et al, 1972). A simple and rapid method, using a modification of Grinnell's technique is reported here. Essentially, microspheres coated with Concavalin A are used to bind to glycosylated regions of the palatal shelf epithelium and are visualized in the scanning electron microscope (SEM).

Machine learning algorithm for automatic detection of CT-identifiable hyperdense lesions associated with traumatic brain injury

NASA Astrophysics Data System (ADS)

Keshavamurthy, Krishna N.; Leary, Owen P.; Merck, Lisa H.; Kimia, Benjamin; Collins, Scott; Wright, David W.; Allen, Jason W.; Brock, Jeffrey F.; Merck, Derek

2017-03-01

Traumatic brain injury (TBI) is a major cause of death and disability in the United States. Time to treatment is often related to patient outcome. Access to cerebral imaging data in a timely manner is a vital component of patient care. Current methods of detecting and quantifying intracranial pathology can be time-consuming and require careful review of 2D/3D patient images by a radiologist. Additional time is needed for image protocoling, acquisition, and processing. These steps often occur in series, adding more time to the process and potentially delaying time-dependent management decisions for patients with traumatic brain injury. Our team adapted machine learning and computer vision methods to develop a technique that rapidly and automatically detects CT-identifiable lesions. Specifically, we use scale invariant feature transform (SIFT)1 and deep convolutional neural networks (CNN)2 to identify important image features that can distinguish TBI lesions from background data. Our learning algorithm is a linear support vector machine (SVM)3. Further, we also employ tools from topological data analysis (TDA) for gleaning insights into the correlation patterns between healthy and pathological data. The technique was validated using 409 CT scans of the brain, acquired via the Progesterone for the Treatment of Traumatic Brain Injury phase III clinical trial (ProTECT_III) which studied patients with moderate to severe TBI4. CT data were annotated by a central radiologist and included patients with positive and negative scans. Additionally, the largest lesion on each positive scan was manually segmented. We reserved 80% of the data for training the SVM and used the remaining 20% for testing. Preliminary results are promising with 92.55% prediction accuracy (sensitivity = 91.15%, specificity = 93.45%), indicating the potential usefulness of this technique in clinical scenarios.

Cardiovascular Computed Tomography Phantom Fabrication and Characterization through the Tailored Properties of Polymeric Composites and Cellular Foams

NASA Astrophysics Data System (ADS)

Hoy, Carlton F. O.

The overall objective of this thesis was to control the fabrication technique and relevant material properties for phantom devices designated for computed tomography (CT) scanning. Fabrication techniques using polymeric composites and foams were detailed together with parametric studies outlining the fundamentals behind the changes in material properties which affect the characteristic CT number. The composites fabricated used polyvinylidene fluoride (PVDF), thermoplastic polyurethane (TPU) and polyethylene (PE) with hydroxylapatite (hA) as additive with different composites made by means of different weight percentages of additive. Polymeric foams were fabricated through a batch foaming technique with the heating time controlled to create different levels of foams. Finally, the effect of fabricated phantoms under varied scanning media was assessed to determine whether self-made phantoms can be scanned accurately under non-water or rigid environments allowing for the future development of complex shaped or fragile material types.

Characterization of a subwavelength-scale 3D void structure using the FDTD-based confocal laser scanning microscopic image mapping technique.

PubMed

Choi, Kyongsik; Chon, James W; Gu, Min; Lee, Byoungho

2007-08-20

In this paper, a simple confocal laser scanning microscopic (CLSM) image mapping technique based on the finite-difference time domain (FDTD) calculation has been proposed and evaluated for characterization of a subwavelength-scale three-dimensional (3D) void structure fabricated inside polymer matrix. The FDTD simulation method adopts a focused Gaussian beam incident wave, Berenger's perfectly matched layer absorbing boundary condition, and the angular spectrum analysis method. Through the well matched simulation and experimental results of the xz-scanned 3D void structure, we first characterize the exact position and the topological shape factor of the subwavelength-scale void structure, which was fabricated by a tightly focused ultrashort pulse laser. The proposed CLSM image mapping technique based on the FDTD can be widely applied from the 3D near-field microscopic imaging, optical trapping, and evanescent wave phenomenon to the state-of-the-art bio- and nanophotonics.

Locating knots by industrial tomography- A feasibility study

Treesearch

Fred W. Taylor; Francis G. Wagner; Charles W. McMillin; Ira L. Morgan; Forrest F. Hopkins

1984-01-01

Industrial photon tomography was used to scan four southern pine logs and one red oak log. The logs were scanned at 16 cross-sectional slice planes located 1 centimeter apart along their longitudinal axes. Tomographic reconstructions were made from the scan data collected at these slice planes, and a cursory image analysis technique was developed to locate the log...

Automated Slide Scanning and Segmentation in Fluorescently-labeled Tissues Using a Widefield High-content Analysis System.

PubMed

Poon, Candice C; Ebacher, Vincent; Liu, Katherine; Yong, Voon Wee; Kelly, John James Patrick

2018-05-03

Automated slide scanning and segmentation of fluorescently-labeled tissues is the most efficient way to analyze whole slides or large tissue sections. Unfortunately, many researchers spend large amounts of time and resources developing and optimizing workflows that are only relevant to their own experiments. In this article, we describe a protocol that can be used by those with access to a widefield high-content analysis system (WHCAS) to image any slide-mounted tissue, with options for customization within pre-built modules found in the associated software. Not originally intended for slide scanning, the steps detailed in this article make it possible to acquire slide scanning images in the WHCAS which can be imported into the associated software. In this example, the automated segmentation of brain tumor slides is demonstrated, but the automated segmentation of any fluorescently-labeled nuclear or cytoplasmic marker is possible. Furthermore, there are a variety of other quantitative software modules including assays for protein localization/translocation, cellular proliferation/viability/apoptosis, and angiogenesis that can be run. This technique will save researchers time and effort and create an automated protocol for slide analysis.

Nonlinear analysis and dynamic compensation of stylus scanning measurement with wide range

NASA Astrophysics Data System (ADS)

Hui, Heiyang; Liu, Xiaojun; Lu, Wenlong

2011-12-01

Surface topography is an important geometrical feature of a workpiece that influences its quality and functions such as friction, wearing, lubrication and sealing. Precision measurement of surface topography is fundamental for product quality characterizing and assurance. Stylus scanning technique is a widely used method for surface topography measurement, and it is also regarded as the international standard method for 2-D surface characterizing. Usually surface topography, including primary profile, waviness and roughness, can be measured precisely and efficiently by this method. However, by stylus scanning method to measure curved surface topography, the nonlinear error is unavoidable because of the difference of horizontal position of the actual measured point from given sampling point and the nonlinear transformation process from vertical displacement of the stylus tip to angle displacement of the stylus arm, and the error increases with the increasing of measuring range. In this paper, a wide range stylus scanning measurement system based on cylindrical grating interference principle is constructed, the originations of the nonlinear error are analyzed, the error model is established and a solution to decrease the nonlinear error is proposed, through which the error of the collected data is dynamically compensated.

Radiation exposure from Chest CT: Issues and Strategies

PubMed Central

Maher, Michael M.; Rizzo, Stefania; Kanarek, David; Shephard, Jo-Anne O.

2004-01-01

Concerns have been raised over alleged overuse of CT scanning and inappropriate selection of scanning methods, all of which expose patients to unnecessary radiation. Thus, it is important to identify clinical situations in which techniques with lower radiation dose such as plain radiography or no radiation such as MRI and occasionally ultrasonography can be chosen over CT scanning. This article proposes the arguments for radiation dose reduction in CT scanning of the chest and discusses recommended practices and studies that address means of reducing radiation exposure associated with CT scanning of the chest. PMID:15082885

Advanced scanning probe lithography.

PubMed

Garcia, Ricardo; Knoll, Armin W; Riedo, Elisa

2014-08-01

The nanoscale control afforded by scanning probe microscopes has prompted the development of a wide variety of scanning-probe-based patterning methods. Some of these methods have demonstrated a high degree of robustness and patterning capabilities that are unmatched by other lithographic techniques. However, the limited throughput of scanning probe lithography has prevented its exploitation in technological applications. Here, we review the fundamentals of scanning probe lithography and its use in materials science and nanotechnology. We focus on robust methods, such as those based on thermal effects, chemical reactions and voltage-induced processes, that demonstrate a potential for applications.

Surface Characterization.

ERIC Educational Resources Information Center

Fulghum, J. E.; And Others

1989-01-01

This review is divided into the following analytical methods: ion spectroscopy, electron spectroscopy, scanning tunneling microscopy, atomic force microscopy, optical spectroscopy, desorption techniques, and X-ray techniques. (MVL)

Failure of technetium bone scanning to detect pseudarthroses in spinal fusion for scoliosis

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hannon, K.M.; Wetta, W.J.

1977-01-01

A prospective study of 11 patients suggests that present techniques of technetium bone scanning do not assist in recognizing the presence of well-established pseudarthrosis in spinal fusions for scoliosis.

Skeletal scintigraphy and quantitative tracer studies in metabolic bone disease

NASA Astrophysics Data System (ADS)

Fogelman, Ignac

Bone scan imaging with the current bone seeking radiopharmaceuticals, the technetium-99m labelled diphosphonates, has dramatically improved our ability to evaluate skeletal pathology. In this thesis, chapter 1 presents a review of the history of bone scanning, summarises present concepts as to the mechanism of uptake of bone seeking agents and briefly illustrates the role of bone scanning in clinical practice. In chapter 2 the applications of bone scan imaging and quantitative tracer techniques derived from the bone scan in the detection of metabolic bone disease are discussed. Since skeletal uptake of Tc-99m diphosphonate depends upon skeletal metabolism one might expect that the bone scan would be of considerable value in the assessment of metabolic bone disease. However in these disorders the whole skeleton is often diffusely involved by the metabolic process and simple visual inspection of the scan image may not reveal the uniformly increased uptake of tracer. Certain patterns of bone scan abnormality have, however, been reported in patients with primary hyperparathyroidism and renal osteo-dystrophy; the present studies extend these observations and introduce the concept of "metabolic features" which are often recognisable in conditions with generalised increased bone turnover. As an aid to systematic recognition of these features on a given bone scan image a semi-quantitative scoring system, the metabolic index, was introduced. The metabolic index allowed differentiation between various groups of patients with metabolic disorders and a control population. In addition, in a bone scan study of patients with acromegaly, it was found that the metabolic index correlated well with disease activity as measured by serum growth hormone levels. The metabolic index was, however, found to be a relatively insensitive means of identifying disease in individual patients. Patients with increased bone turnover will have an absolute increase in skeletal uptake of tracer. As a means of quantitating this uptake the use of bone to soft-tissue ratios derived from the bone scan image by computer was critically evaluated. The technique was shown to be observer dependent and again found to be of limited value due to the large overlap of patient results with those from control subjects. In chapter 3 the use of bone scan imaging in metabolic bone disease has been compared with radiology. Despite the difficulties mentioned above the metabolic index was employed, and the bone scan found to be the more sensitive investigation in primary hyperparathyroidism, renal osteodystrophy and osteomalacia. In osteoporosis, however, the bone scan was often unable to identify disease and radiology remains the investigation of choice. In a further study comparing bone scanning and radiology in Paget's disease, the bone scan was found to be clearly the more sensitive investigation. As a result of the work described in chapter 2 it became apparent that a sensitive means of quantitating absolute bone uptake of tracer could be of diagnostic value. In chapter 4 a promising new quantitative technique is described in which the 24-hour whole-body retention of Tc-99m diphosphonate (WBR) is measured using a shadow-shield whole-body monitor. At 24 hours after injection, diphosphonate has reached a stable equilibrium in bone reflecting skeletal metabolic activity, while tracer in the soft-tissues of the body has been largely excreted via the urinary tract. It was found that this technique provided a sensitive means of detecting patients with primary hyperparathyroidism, osteomalacia, renal osteodystrophy and Paget's disease and that in these conditions all the results from individual patients lay outside the control range. In further studies the WBR technique was shown to be highly reproducible and not subject to any significant technical errors.

Wavelength scanning achieves pixel super-resolution in holographic on-chip microscopy

NASA Astrophysics Data System (ADS)

Luo, Wei; Göröcs, Zoltan; Zhang, Yibo; Feizi, Alborz; Greenbaum, Alon; Ozcan, Aydogan

2016-03-01

Lensfree holographic on-chip imaging is a potent solution for high-resolution and field-portable bright-field imaging over a wide field-of-view. Previous lensfree imaging approaches utilize a pixel super-resolution technique, which relies on sub-pixel lateral displacements between the lensfree diffraction patterns and the image sensor's pixel-array, to achieve sub-micron resolution under unit magnification using state-of-the-art CMOS imager chips, commonly used in e.g., mobile-phones. Here we report, for the first time, a wavelength scanning based pixel super-resolution technique in lensfree holographic imaging. We developed an iterative super-resolution algorithm, which generates high-resolution reconstructions of the specimen from low-resolution (i.e., under-sampled) diffraction patterns recorded at multiple wavelengths within a narrow spectral range (e.g., 10-30 nm). Compared with lateral shift-based pixel super-resolution, this wavelength scanning approach does not require any physical shifts in the imaging setup, and the resolution improvement is uniform in all directions across the sensor-array. Our wavelength scanning super-resolution approach can also be integrated with multi-height and/or multi-angle on-chip imaging techniques to obtain even higher resolution reconstructions. For example, using wavelength scanning together with multi-angle illumination, we achieved a halfpitch resolution of 250 nm, corresponding to a numerical aperture of 1. In addition to pixel super-resolution, the small scanning steps in wavelength also enable us to robustly unwrap phase, revealing the specimen's optical path length in our reconstructed images. We believe that this new wavelength scanning based pixel super-resolution approach can provide competitive microscopy solutions for high-resolution and field-portable imaging needs, potentially impacting tele-pathology applications in resource-limited-settings.

Experimental characterization of the perceptron laser rangefinder

NASA Technical Reports Server (NTRS)

Kweon, I. S.; Hoffman, Regis; Krotkov, Eric

1991-01-01

In this report, we characterize experimentally a scanning laser rangefinder that employs active sensing to acquire three-dimensional images. We present experimental techniques applicable to a wide variety of laser scanners, and document the results of applying them to a device manufactured by Perceptron. Nominally, the sensor acquires data over a 60 deg x 60 deg field of view in 256 x 256 pixel images at 2 Hz. It digitizes both range and reflectance pixels to 12 bits, providing a maximum range of 40 m and a depth resolution of 1 cm. We present methods and results from experiments to measure geometric parameters including the field of view, angular scanning increments, and minimum sensing distance. We characterize qualitatively problems caused by implementation flaws, including internal reflections and range drift over time, and problems caused by inherent limitations of the rangefinding technology, including sensitivity to ambient light and surface material. We characterize statistically the precision and accuracy of the range measurements. We conclude that the performance of the Perceptron scanner does not compare favorably with the nominal performance, that scanner modifications are required, and that further experimentation must be conducted.

Modelling an advanced ManPAD with dual band detectors and a rosette scanning seeker head

NASA Astrophysics Data System (ADS)

Birchenall, Richard P.; Richardson, Mark A.; Butters, Brian; Walmsley, Roy

2012-01-01

Man Portable Air Defence Systems (ManPADs) have been a favoured anti aircraft weapon since their appearance on the military proliferation scene in the mid 1960s. Since this introduction there has been a 'cat and mouse' game of Missile Countermeasures (CMs) and the aircraft protection counter counter measures (CCMs) as missile designers attempt to defeat the aircraft platform protection equipment. Magnesium Teflon Viton (MTV) flares protected the target aircraft until the missile engineers discovered the art of flare rejection using techniques including track memory and track angle bias. These early CCMs relied upon CCM triggering techniques such as the rise rate method which would just sense a sudden increase in target energy and assume that a flare CM had been released by the target aircraft. This was not as reliable as was first thought as aspect changes (bringing another engine into the field of view) or glint from the sun could inadvertently trigger a CCM when not needed. The introduction of dual band detectors in the 1980s saw a major advance in CCM capability allowing comparisons between two distinct IR bands to be made thus allowing the recognition of an MTV flare to occur with minimal false alarms. The development of the rosette scan seeker in the 1980s complemented this advancement allowing the scene in the missile field of view (FOV) to be scanned by a much smaller (1/25) instantaneous FOV (IFOV) with the spectral comparisons being made at each scan point. This took the ManPAD from a basic IR energy detector to a pseudo imaging system capable of analysing individual elements of its overall FOV allowing more complex and robust CCM to be developed. This paper continues the work published in [1,2] and describes the method used to model an advanced ManPAD with a rosette scanning seeker head and robust CCMs similar to the Raytheon Stinger RMP.

Validation study of an interpolation method for calculating whole lung volumes and masses from reduced numbers of CT-images in ponies.

PubMed

Reich, H; Moens, Y; Braun, C; Kneissl, S; Noreikat, K; Reske, A

2014-12-01

Quantitative computer tomographic analysis (qCTA) is an accurate but time intensive method used to quantify volume, mass and aeration of the lungs. The aim of this study was to validate a time efficient interpolation technique for application of qCTA in ponies. Forty-one thoracic computer tomographic (CT) scans obtained from eight anaesthetised ponies positioned in dorsal recumbency were included. Total lung volume and mass and their distribution into four compartments (non-aerated, poorly aerated, normally aerated and hyperaerated; defined based on the attenuation in Hounsfield Units) were determined for the entire lung from all 5 mm thick CT-images, 59 (55-66) per animal. An interpolation technique validated for use in humans was then applied to calculate qCTA results for lung volumes and masses from only 10, 12, and 14 selected CT-images per scan. The time required for both procedures was recorded. Results were compared statistically using the Bland-Altman approach. The bias ± 2 SD for total lung volume calculated from interpolation of 10, 12, and 14 CT-images was -1.2 ± 5.8%, 0.1 ± 3.5%, and 0.0 ± 2.5%, respectively. The corresponding results for total lung mass were -1.1 ± 5.9%, 0.0 ± 3.5%, and 0.0 ± 3.0%. The average time for analysis of one thoracic CT-scan using the interpolation method was 1.5-2 h compared to 8 h for analysis of all images of one complete thoracic CT-scan. The calculation of pulmonary qCTA data by interpolation from 12 CT-images was applicable for equine lung CT-scans and reduced the time required for analysis by 75%. Copyright © 2014 Elsevier Ltd. All rights reserved.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Henderson, Michael A.; Lyubinetsky, Igor

The field of heterogeneous photocatalysis has grown considerably in the decades since Fujishima and Honda's ground-breaking publications of photoelectrochemistry on TiO2. Numerous review articles continue to point to both progress made in the use of heterogeneous materials (such as TiO2) to perform photoconversion processes, and the many opportunities and challenges in heterogeneous photocatalysis research such as solar energy conversion and environmental remediation. The past decade has also seen an increase in the use of molecular-level approaches applied to model single crystal surfaces in an effort to obtain new insights into photocatalytic phenomena. In particular, scanning probe techniques (SPM) have enabledmore » researchers to take a ‘nanoscale’ approach to photocatalysis that includes interrogation of the reactivities of specific sites and adsorbates on a model photocatalyst surface. The rutile TiO2(110) surface has become the prototypical oxide single crystal surface for fundamental studies of many interfacial phenomena. In particular, TiO2(110) has become an excellent model surface for probing photochemical and photocatalytic reactions at the molecular level. A variety of experimental approaches have emerged as being ideally suited for studying photochemical reactions on TiO2(110), including desorption-oriented approaches and electronic spectroscopies, but perhaps the most promising techniques for evaluating site-specific properties are those of SPM. In this review, we highlight the growing use of SPM techniques in providing molecular-level insights into surface photochemistry on the model photocatalyst surface of rutile TiO2(110). Our objective is to both illustrate the unique knowledge that scanning probe techniques have already provided the field of photocatalysis, and also to motivate a new generation of effort into the use of such approaches to obtain new insights into the molecular level details of photochemical events occurring at interfaces. Discussion will start with an examination of how scanning probe techniques are being used to characterize the TiO2(110) surface in ways that are relevant to photocatalysis. We will then discuss specific classes of photochemical reaction on TiO2(110) for which SPM has proven indispensible in providing unique molecular-level insights, and conclude with discussion of future areas in which SPM studies may prove valuable to photocatalysis on TiO2. This work was supported by the US Department of Energy, Office of Basic Energy Sciences, Division of Chemical Sciences, Geosciences & Biosciences. I.L. was partially supported by a Pacific Northwest National Laboratory (PNNL) Chemical Imaging Initiative project. PNNL is a multiprogram national laboratory operated for DOE by Battelle.« less

High-speed biometrics ultrasonic system for 3D fingerprint imaging

NASA Astrophysics Data System (ADS)

Maev, Roman G.; Severin, Fedar

2012-10-01

The objective of this research is to develop a new robust fingerprint identification technology based upon forming surface-subsurface (under skin) ultrasonic 3D images of the finger pads. The presented work aims to create specialized ultrasonic scanning methods for biometric purposes. Preliminary research has demonstrated the applicability of acoustic microscopy for fingerprint reading. The additional information from internal skin layers and dermis structures contained in the scan can essentially improve confidence in the identification. Advantages of this system include high resolution and quick scanning time. Operating in pulse-echo mode provides spatial resolution up to 0.05 mm. Technology advantages of the proposed technology are the following: • Full-range scanning of the fingerprint area "nail to nail" (2.5 x 2.5 cm) can be done in less than 5 sec with a resolution of up to 1000 dpi. • Collection of information about the in-depth structure of the fingerprint realized by the set of spherically focused 50 MHz acoustic lens provide the resolution ~ 0.05 mm or better • In addition to fingerprints, this technology can identify sweat porous at the surface and under the skin • No sensitivity to the contamination of the finger's surface • Detection of blood velocity using Doppler effect can be implemented to distinguish living specimens • Utilization as polygraph device • Simple connectivity to fingerprint databases obtained with other techniques • The digitally interpolated images can then be enhanced allowing for greater resolution • Method can be applied to fingernails and underlying tissues, providing more information • A laboratory prototype of the biometrics system based on these described principles was designed, built and tested. It is the first step toward a practical implementation of this technique.

Change detection of medical images using dictionary learning techniques and principal component analysis.

PubMed

Nika, Varvara; Babyn, Paul; Zhu, Hongmei

2014-07-01

Automatic change detection methods for identifying the changes of serial MR images taken at different times are of great interest to radiologists. The majority of existing change detection methods in medical imaging, and those of brain images in particular, include many preprocessing steps and rely mostly on statistical analysis of magnetic resonance imaging (MRI) scans. Although most methods utilize registration software, tissue classification remains a difficult and overwhelming task. Recently, dictionary learning techniques are being used in many areas of image processing, such as image surveillance, face recognition, remote sensing, and medical imaging. We present an improved version of the EigenBlockCD algorithm, named the EigenBlockCD-2. The EigenBlockCD-2 algorithm performs an initial global registration and identifies the changes between serial MR images of the brain. Blocks of pixels from a baseline scan are used to train local dictionaries to detect changes in the follow-up scan. We use PCA to reduce the dimensionality of the local dictionaries and the redundancy of data. Choosing the appropriate distance measure significantly affects the performance of our algorithm. We examine the differences between [Formula: see text] and [Formula: see text] norms as two possible similarity measures in the improved EigenBlockCD-2 algorithm. We show the advantages of the [Formula: see text] norm over the [Formula: see text] norm both theoretically and numerically. We also demonstrate the performance of the new EigenBlockCD-2 algorithm for detecting changes of MR images and compare our results with those provided in the recent literature. Experimental results with both simulated and real MRI scans show that our improved EigenBlockCD-2 algorithm outperforms the previous methods. It detects clinical changes while ignoring the changes due to the patient's position and other acquisition artifacts.

Investigation of quartz grain surface textures by atomic force microscopy for forensic analysis.

PubMed

Konopinski, D I; Hudziak, S; Morgan, R M; Bull, P A; Kenyon, A J

2012-11-30

This paper presents a study of quartz sand grain surface textures using atomic force microscopy (AFM) to image the surface. Until now scanning electron microscopy (SEM) has provided the primary technique used in the forensic surface texture analysis of quartz sand grains as a means of establishing the provenance of the grains for forensic reconstructions. The ability to independently corroborate the grain type classifications is desirable and provides additional weight to the findings of SEM analysis of the textures of quartz grains identified in forensic soil/sediment samples. AFM offers a quantitative means of analysis that complements SEM examination, and is a non-destructive technique that requires no sample preparation prior to scanning. It therefore has great potential to be used for forensic analysis where sample preservation is highly valuable. By taking quantitative topography scans, it is possible to produce 3D representations of microscopic surface textures and diagnostic features for examination. Furthermore, various empirical measures can be obtained from analysing the topography scans, including arithmetic average roughness, root-mean-square surface roughness, skewness, kurtosis, and multiple gaussian fits to height distributions. These empirical measures, combined with qualitative examination of the surfaces can help to discriminate between grain types and provide independent analysis that can corroborate the morphological grain typing based on the surface textures assigned using SEM. Furthermore, the findings from this study also demonstrate that quartz sand grain surfaces exhibit a statistically self-similar fractal nature that remains unchanged across scales. This indicates the potential for a further quantitative measure that could be utilised in the discrimination of quartz grains based on their provenance for forensic investigations. Copyright © 2012 Elsevier Ireland Ltd. All rights reserved.

Advanced Methods of Nondestructive Inspection of Composite Structures Based on Limited Angle X-Ray Computed Tomography

NASA Astrophysics Data System (ADS)

Bostaph, Ekaterina

This research aimed to study the potential for breaking through object size limitations of current X-ray computed tomography (CT) systems by implementing a limited angle scanning technique. CT stands out among other industrial nondestructive inspection (NDI) methods due to its unique ability to perform 3D volumetric inspection, unmatched micro-focus resolution, and objectivity that allows for automated result interpretation. This work attempts to advance NDI technique to enable microstructural material characterization and structural diagnostics of composite structures, where object sizes often prohibit the application of full 360° CT. Even in situations where the objects can be accommodated within existing micro-CT configuration, achieving sufficient magnification along with full rotation may not be viable. An effort was therefore made to achieve high-resolution scans from projection datasets with limited angular coverage (less than 180°) by developing effective reconstruction algorithms in conjunction with robust scan acquisition procedures. Internal features of inspected objects barely distinguishable in a 2D X-ray radiograph can be enhanced by additional projections that are reconstructed to a stack of slices, dramatically improving depth perception, a technique referred to as digital tomosynthesis. Building on the success of state-of-the-art medical tomosynthesis systems, this work sought to explore the feasibility of this technique for composite structures in aerospace applications. The challenge lies in the fact that the slices generated in medical tomosynthesis are too thick for relevant industrial applications. In order to adapt this concept to composite structures, reconstruction algorithms were expanded by implementation of optimized iterative stochastic methods (capable of reducing noise and refining scan quality) which resulted in better depth perception. The optimal scan acquisition procedure paired with the improved reconstruction algorithm facilitated higher in-plane and depth resolution compared to the clinical application. The developed limited angle tomography technique was demonstrated to be able to detect practically significant manufacturing defects (voids) and structural damage (delaminations) critical to structural integrity of composite parts. Keeping in mind the intended real-world aerospace applications where objects often have virtually unlimited in-plane dimensions, the developed technique of partial scanning could potentially extend the versatility of CT-based inspection and enable game changing NDI systems.

Spectral line inversion for sounding of stratospheric minor constituents by infrared heterodyne technique from balloon altitudes

NASA Technical Reports Server (NTRS)

Abbas, M. M.; Shapiro, G. L.; Allario, F.; Alvarez, J. M.

1981-01-01

A combination of two different techniques for the inversion of infrared laser heterodyne measurements of tenuous gases in the stratosphere by solar occulation is presented which incorporates the advantages of each technique. An experimental approach and inversion technique are developed which optimize the retrieval of concentration profiles by incorporating the onion peel collection scheme into the spectral inversion technique. A description of an infrared heterodyne spectrometer and the mode of observations for solar occulation measurement is presented, and the results of inversions of some synthetic ClO spectral lines corresponding to solar occulation limb-scans of the stratosphere are examined. A comparison between the new techniques and one of the current techniques indicates that considerable improvement in the accuracy of the retrieved profiles can be achieved. It is found that noise affects the accuracy of both techniques but not in a straightforward manner since there is interaction between the noise level, noise propagation through inversion, and the number of scans leading to an optimum retrieval.

Solar cell anomaly detection method and apparatus

NASA Technical Reports Server (NTRS)

Miller, Emmett L. (Inventor); Shumka, Alex (Inventor); Gauthier, Michael K. (Inventor)

1981-01-01

A method is provided for detecting cracks and other imperfections in a solar cell, which includes scanning a narrow light beam back and forth across the cell in a raster pattern, while monitoring the electrical output of the cell to find locations where the electrical output varies significantly. The electrical output can be monitored on a television type screen containing a raster pattern with each point on the screen corresponding to a point on the solar cell surface, and with the brightness of each point on the screen corresponding to the electrical output from the cell which was produced when the light beam was at the corresponding point on the cell. The technique can be utilized to scan a large array of interconnected solar cells, to determine which ones are defective.

Four years experience in APMS star plate processing - Results and future plans. [Automated Proper Motion Study

NASA Technical Reports Server (NTRS)

Newcomb, J. S.

1975-01-01

The present paper describes an automated system for measuring stellar proper motions on the basis of information contained in photographic plates. In this system, the images on a star plate are digitized by a scanning microdensitometer using light from a He-Ne gas laser, and a special-purpose computer arranges the measurements in computer-compatible form on magnetic tape. The scanning and image-reconstruction processes are briefly outlined, and the image-evaluation techniques are discussed. It is shown that the present system has been especially successful in measuring the proper motions of low-luminosity stars, including 119 stars with less than 1/10,000 of the solar bolometric luminosity. Plans for measurements of high-density Milky Way star plates are noted.