Development of a miniaturized hour-glass shaped fatigue specimen

NASA Astrophysics Data System (ADS)

Miwa, Y.; Jitsukawa, S.; Hishinuma, A.

1998-10-01

Diametral strain-controlled push-pull fatigue tests with zero mean strain were carried out with miniaturized hour-glass shaped specimens of an austenitic stainless steel in solution annealed condition at room temperature. The specimens had a diameter of 1.25 mm at the minimum cross section and a total length of 25.4 mm. The number of cycles to failure ( Nf) was equal to or slightly greater than that obtained with standard size specimens. Nf was also revealed to be rather insensitive to the specimen load axis offset, indicating that the requirement of the specimen alignment to the load axis was not very severe for the miniaturized specimen.

Analysis of the stiffness and load-bearing capacity of glued laminated timber beams reinforced with strands

NASA Astrophysics Data System (ADS)

Sardiko, R.; Rocens, K.; Iejavs, J.; Jakovlevs, V.; Ziverts, K.

2017-10-01

In this paper a benefit of glulam pinewood beams reinforced strands is discussed. In the first phase, series of pull-out tests were performed on specimens made up of different types of glue (melamine-urea-formaldehyde, epoxy and others) to detect pull-out force and failure mode of a specimens. In the second phase, series of equal cross-section glulam beams with strand and rod reinforcement were theoretically analysed using transformed cross-section method. Additionally, series of experimental testing were made. Benefits of strand reinforcement use as glulam beams’ reinforcement were identified and examined the possibility of one glue type application in all operations of reinforced glulam beams manufacturing.

The relationship between cross-sectional shapes and FTIR profiles in synthetic wig fibers and their discriminating abilities - An evidential value perspective.

PubMed

Joslin Yogi, Theresa A; Penrod, Michael; Holt, Melinda; Buzzini, Patrick

2018-02-01

Wig fragments or fibers may occasionally be recognized as potential physical evidence during criminal investigations. While analytical methods traditionally adopted for the examination of textile fibers are utilized for the characterizations and comparisons of wig specimens, it is essential to understand in deeper detail the valuable contribution of features of these non-routine evidentiary materials as well as the relationship of the gathered analytical data. This study explores the dependence between the microscopic features of cross-sectional shapes and the polymer type gathered by Fourier transform infrared (FTIR) spectroscopy. The discriminating power of the two methods of cross-sectioning and FTIR spectroscopy was also investigated. Forty-one synthetic wigs varying in both quality and price were collected: twenty-three brown, twelve blondes and six black samples. The collected samples were observed using light microscopy methods (bright field illumination and polarized light), before obtaining cross-sections using the Joliff method and analyze them using FTIR spectroscopy. The forty-one samples were divided into ten groups based on one or more of the ten types of cross-sectional shapes that were observed. The majority of encountered cross-sectional shapes were defined as horseshoe, dog bone and lobular. Infrared spectroscopy confirmed modacrylic to be the most prevalent fiber type. Blends of modacrylic and polyvinyl chloride fibers were also observed as well as polypropylene wig samples. The Goodman and Kruskal lambda statistical test was used and showed that the cross-sectional shape and infrared profile were related. From an evidentiary value perspective, this finding has implications when addressing questions about a common source between questioned wig specimens and a wig reference sample. Copyright © 2017 Elsevier B.V. All rights reserved.

An alternative simple method for preparing and preserving cross-section of leaves and roots in herbaceous plants: Case study in Orchidaceae

NASA Astrophysics Data System (ADS)

Metusala, D.

2017-07-01

This alternative method provides a simple and faster procedure for preparing cross-sections of leaves and roots in herbaceous plants, especially for living specimens of orchids (Orchidaceae). This method used a clamp-on hand sliding microtome to make cross-sections of leaves and roots, with sections preserved inside the microtubes containing preservation liquid. This preservation technique allowed the sections to be restained and to be used for further usage in future. This method was more practical than the paraffin embedding method because it does not need the additional steps of paraffin embedding and deparaffinization. It may also provide better cross-section results than free-hand sectioning method. The procedure is very feasible and is recommended for use in plant anatomy observation.

Rapidly solidified metal coatings by peen plating

NASA Technical Reports Server (NTRS)

Chu, H. P.

1987-01-01

Specimens of 7075-T6 aluminum alloy were peen plated with rapidly solidified tin-lead and aluminum powders, and the cross-sections of the coated specimens were examined by light and electron microscopy. The properties of the peen plated specimens were also compared with those of shot peened specimens without any coating. It is found that peen plating with rapidly solidified metals improves the fatigue properties of the coated samples to a greater extent than shot peening alone. Specimens of 7075-T6 alloy peen plated with rapidly solidified tin-lead and aluminum exhibited better fatigue resistance than shot peened specimens in both air and salt water.

Laboratory Reproduction and Failure Analysis of Cracked Orbiter Reaction Control System Niobium Thruster Injectors

NASA Technical Reports Server (NTRS)

Jacobs, Jeremy B.; Castner, Willard L.

2007-01-01

A viewgraph presentation describing cracks and failure analysis of an orbiter reaction control system is shown. The topics include: 1) Endeavour STS-113 Landing; 2) RCS Thruster; 3) Thruster Cross-Section; 4) RCS Injector; 5) RCS Thruster, S/N 120l 6) Counterbore Cracks; 7) Relief Radius Cracks; 8) RCS Thruster Cracking History; 9) Thruster Manufacturing Timelines; 10) Laboratory Reproduction of Injector Cracking; 11) The Brownfield Specimen; 12) HF EtchantTests/Specimen Loading; 13) Specimen #3 HF + 600F; 14) Specimen #3 IG Fracture; 15) Specimen #5 HF + 600F; 16) Specimen #5 Popcorn ; 17) Specimen #5 Cleaned and Bent; 18) HF Exposure Test Matrix; 19) Krytox143AC Tests; 20) KrytoxTests/Specimen Loading; 21) Specimen #13 Krytox + 600F; and 22) KrytoxExposure Test Matrix.

Acoustic Emission Monitoring of Multicell Reinforced Concrete Box Girders Subjected to Torsion

PubMed Central

Bagherifaez, Marya; Behnia, Arash; Majeed, Abeer Aqeel; Hwa Kian, Chai

2014-01-01

Reinforced concrete (RC) box girders are a common structural member for road bridges in modern construction. The hollow cross-section of a box girder is ideal in carrying eccentric loads or torques introduced by skew supports. This study employed acoustic emission (AE) monitoring on multicell RC box girder specimens subjected to laboratory-based torsion loading. Three multicell box girder specimens with different cross-sections were tested. The aim is to acquire AE analysis data indicative for characterizing torsion fracture in the box girders. It was demonstrated through appropriate parametric analysis that the AE technique could be utilized to effectively classify fracture developed in the specimens for describing their mechanical behavior under torsion. AE events localization was presented to illustrate the trend of crack and damage propagation in different stages of fracture. It could be observed that spiral-like patterns of crack were captured through AE damage localization system and damage was quantified successfully in different stages of fracture by using smoothed b-value analysis. PMID:25180203

An experimental investigation of Iosipescu specimen for composite materials

NASA Technical Reports Server (NTRS)

Ho, H.; Tsai, M. Y.; Morton, J.; Farley, G. L.

1991-01-01

A detailed experimental evaluation of the Iosipescu specimen tested in the modified Wyoming fixture is presented. Moire interferometry is employed to determine the deformation of unidirectional and cross-ply graphite-epoxy specimens. The results of the moire experiments are compared to those from the traditional strain-gage method. It is shown that the strain-gage readings from one surface of a specimen together with corresponding data from moire interferometry on the opposite face documented an extreme sensitivity of some fiber orientations to twisting. A localized hybrid analysis is introduced to perform efficient reduction of moire data, producing whole-field strain distributions in the specimen test sections.

Behaviour of wrapped cold-formed steel columns under different loading conditions

NASA Astrophysics Data System (ADS)

Baabu, B. Hari; Sreenath, S.

2017-07-01

The use of Cold Formed Steel (CFS) sections as structural members is widely accepted because of its light nature. However, the load carrying capacity of these sections will be less compared to hot rolled sections. This study is meant to analyze the possibility of strengthening cold formed members by wrapping it with Glass Fiber Reinforced Polymer (GFRP) laminates. Light gauge steel columns of cross sectional dimensions 100mm x 50mm x 3.15mm were taken for this study. The effective length of the section is about 750mm. A total of 8 specimens including the control specimen is tested under axial and eccentric loading. The columns were tested keeping both ends hinged. For both loading cases the buckling behaviour, ultimate load carrying capacity and load-deflection characteristics of the CFS columns were analyzed. The GFRP laminates were wrapped on columns in three different ways such that wrapping the outer surface of web and flange throughout the length of specimen, wrapping the outer surface of web alone throughout the length of specimen and wrapping the outer surface of web and flange for the upper half length of the specimen where the buckling is expected. For both loading cases, the results indicated that the column with wrapping at the outer surface of web and flange throughout the length of specimen provides better strength for it.

Resin distribution in second-growth ponderosa pine

Treesearch

B.H. Paul

1955-01-01

In a study of specific gravity of second-growth ponderosa pine, there was visible evidence of resin in a part of the specific gravity specimens. Each specimen contained 10 annual growth rings in cross sections taken at 4 heights in the merchantable length of the trees. Since the presence of resin introduced an uncertain amount of error in the specific gravity values,...

A Protocol for Aging Anurans Using Skeletochronology

USGS Publications Warehouse

McCreary, Brome; Pearl, Christopher A.; Adams, Michael J.

2008-01-01

Age distribution information can be an important part of understanding the biology of any population. Age estimates collected from the annual growth rings found in tooth and bone cross sections, often referred to as Lines of Arrested Growth (LAGs), have been used in the study of various animals. In this manual, we describe in detail all necessary steps required to obtain estimates of age from anuran bone cross sections via skeletochronological assessment. We include comprehensive descriptions of how to fix and decalcify toe specimens (phalanges), process a phalange prior to embedding, embed the phalange in paraffin, section the phalange using a microtome, stain and mount the cross sections of the phalange and read the LAGs to obtain age estimates.

Microscopic observations of osteoblast growth on micro-arc oxidized β titanium

NASA Astrophysics Data System (ADS)

Chen, Hsien-Te; Chung, Chi-Jen; Yang, Tsai-Ching; Tang, Chin-Hsin; He, Ju-Liang

2013-02-01

Titanium alloys are widely used in orthopedic and dental implants, owing to their excellent physical properties and biocompatibility. By using the micro-arc oxidation (MAO), we generated anatase-rich (A-TiO2) and rutile-rich (R-TiO2) titanium dioxide coatings, individually on β-Ti alloy, in which the latter achieved an enhanced in vitro and in vivo performance. Thoroughly elucidating how the osteoblasts interact with TiO2 coatings is of worthwhile interest. This study adopts the focused ion beam (FIB) to section off the TiO2 coated samples for further scanning electron microscope (SEM) and transmission electron microscope (TEM) observation. The detailed crystal structures of the TiO2 coated specimens are also characterized. Experimental results indicate osteoblasts adhered more tenaciously and grew conformably with more lamellipodia extent on the R-TiO2 specimen than on the A-TiO2 and raw β-Ti specimens. FIB/SEM cross-sectional images of the cell/TiO2 interface revealed micro gaps between the cell membrane and contact surface of A-TiO2 specimen, while it was not found on the R-TiO2 specimen. Additionally, the number of adhered and proliferated cells on the R-TiO2 specimen was visually greater than the others. Closely examining EDS line scans and elemental mappings of the FIB/TEM cross-sectional images of the cell/TiO2 interface reveals both the cell body and interior space of the TiO2 coating contain nitrogen and sulfur (the biological elements in cell). This finding supports the assumption that osteoblast can grow into the porous structure of TiO2 coatings and demonstrating that the R-TiO2 coating formed by MAO serves the best for β-Ti alloys as orthopedic and dental implants.

Masonry Columns Confined by Steel Fiber Composite Wraps

PubMed Central

Borri, Antonio; Castori, Giulio; Corradi, Marco

2011-01-01

The application of steel fiber reinforced polymer (SRP) as a means of increasing the capacity of masonry columns is investigated in this study. The behavior of 23 solid-brick specimens that are externally wrapped by SRP sheets in low volumetric ratios is presented. The specimens are subjected to axial monotonic load until failure occurs. Two widely used types of masonry columns of differing square cross-sections were tested in compression (square and octagonal cross-sections). It is concluded that SRP-confined masonry behaves very much like fiber reinforced polymers (FRP)-confined masonry. Confinement increases both the load-carrying capacity and the deformability of masonry almost linearly with average confining stress. A comparative analysis between experimental and theoretical values computed in compliance with the Italian Council of Research (CNR) was also developed. PMID:28879991

Masonry Columns Confined by Steel Fiber Composite Wraps.

PubMed

Borri, Antonio; Castori, Giulio; Corradi, Marco

2011-01-21

The application of steel fiber reinforced polymer (SRP) as a means of increasing the capacity of masonry columns is investigated in this study. The behavior of 23 solid-brick specimens that are externally wrapped by SRP sheets in low volumetric ratios is presented. The specimens are subjected to axial monotonic load until failure occurs. Two widely used types of masonry columns of differing square cross-sections were tested in compression (square and octagonal cross-sections). It is concluded that SRP-confined masonry behaves very much like fiber reinforced polymers (FRP)-confined masonry. Confinement increases both the load-carrying capacity and the deformability of masonry almost linearly with average confining stress. A comparative analysis between experimental and theoretical values computed in compliance with the Italian Council of Research (CNR) was also developed.

Flexural Behavior of GFRP Tubes Filled with Magnetically Driven Concrete

PubMed Central

Xie, Fang; Chen, Ju; Dong, Xinlong; Feng, Bing

2018-01-01

Experimental investigation of GFRP (glass fiber reinforced polymer) tubes that were filled with magnetically driven concrete was carried out to study the flexural behavior of specimens under bending. Specimens having different cross section and lengths were tested. The test specimens were fabricated by filling magnetically driven concrete into the GFRP tubes and the concrete was vibrated using magnetic force. Specimens vibrated using vibrating tube were also tested for comparison. In addition, specimens having steel reinforcing bars and GFRP bars were both tested to study the effect of reinforcing bars on the magnetically driven concrete. The load-displacement curves, load-strain curves, failure mode, and ultimate strengths of test specimens were obtained. Design methods for the flexural stiffness of test specimens were also discussed in this study. PMID:29316732

Flexural Behavior of GFRP Tubes Filled with Magnetically Driven Concrete.

PubMed

Xie, Fang; Chen, Ju; Dong, Xinlong; Feng, Bing

2018-01-08

Experimental investigation of GFRP (glass fiber reinforced polymer) tubes that were filled with magnetically driven concrete was carried out to study the flexural behavior of specimens under bending. Specimens having different cross section and lengths were tested. The test specimens were fabricated by filling magnetically driven concrete into the GFRP tubes and the concrete was vibrated using magnetic force. Specimens vibrated using vibrating tube were also tested for comparison. In addition, specimens having steel reinforcing bars and GFRP bars were both tested to study the effect of reinforcing bars on the magnetically driven concrete. The load-displacement curves, load-strain curves, failure mode, and ultimate strengths of test specimens were obtained. Design methods for the flexural stiffness of test specimens were also discussed in this study.

Detection and Location of Transverse Matrix Cracks in Cross-Ply Gr/Ep Composites Using Acoustic Emission

NASA Technical Reports Server (NTRS)

Prosser, W. H.; Jackson, K. E.; Kellas, S.; Smith, B. T.; McKeon, J.; Friedman, A.

1995-01-01

Transverse matrix cracking in cross-ply gr/ep laminates was studied with advanced acoustic emission (AE) techniques. The primary goal of this research was to measure the load required to initiate the first transverse matrix crack in cross-ply laminates of different thicknesses. Other methods had been previously used for these measurements including penetrant enhanced radiography, optical microscopy, and audible acoustic microphone measurements. The former methods required that the mechanical test be paused for measurements at load intervals. This slowed the test procedure and did not provide the required resolution in load. With acoustic microphones, acoustic signals from cracks could not be clearly differentiated from other noise sources such as grip damage, specimen slippage, or test machine noise. A second goal for this work was to use the high resolution source location accuracy of the advanced acoustic emission techniques to determine whether the crack initiation site was at the specimen edge or in the interior of the specimen.In this research, advanced AE techniques using broad band sensors, high capture rate digital waveform acquisition, and plate wave propagation based analysis were applied to cross-ply composite coupons with different numbers of 0 and 90 degree plies. Noise signals, believed to be caused by grip damage or specimen slipping, were eliminated based on their plate wave characteristics. Such signals were always located outside the sensor gage length in the gripped region of the specimen. Cracks were confirmed post-test by microscopic analysis of a polished specimen edge, backscatter ultrasonic scans, and in limited cases, by penetrant enhanced radiography. For specimens with three or more 90 degree plies together, there was an exact 1-1 correlation between AE crack signals and observed cracks. The ultrasonic scans and some destructive sectioning analysis showed that the cracks extended across the full width of the specimen. Furthermore, the locations of the cracks from the AE data were in excellent agreement with the locations measured with the microscope. The high resolution source location capability of this technique, combined with an array of sensors, was able to determine that the cracks initiated at the specimen edges, rather than in the interior. For specimens with only one or two 90 degree plies, the crack-like signals were significantly smaller in amplitude and there was not a 1-1 correlation to observed cracks. This was similar to previous results. In this case, however, ultrasonic and destructive sectioning analysis revealed that the cracks did not extend across the specimen. They initiated at the edge, but did not propagate any appreciable distance into the specimen. This explains the much smaller AE signal amplitudes and the difficulty in correlating these signals to actual cracks in this, as well as in the previous study.

THE UTILITY OF RIGHT VENTRICULAR ENDOMYOCARDIAL BIOPSY FOR THE DIAGNOSIS OF XENOGRAFT REJECTION AFTER CD46 PIG-TO-BABOON CARDIAC TRANSPLANTATION

PubMed Central

Ricci, Davide; Tazelaar, Henry D; Miyagi, Naoto; Rao, Vinay P; Pedersen, Rachel A; Kremers, Walter K; Byrne, Guerard W; McGregor, Christopher G A

2007-01-01

Introduction Endomyocardial biopsy (EmBx) is the standard means of establishing cardiac allograft rejection diagnosis. The efficacy of this procedure in xenotransplantation has not been determined. In this study we compare the histology of right ventricular EmBx specimens with the corresponding full cross sections of explanted right ventricle (RV). We also compare RV with the related left ventricle (LV) cross sections. Methods Heterotopic CD46 pig to baboon cardiac xenotransplants (n=64) were studied. RVEmBxs were taken at cardiac explant, using either a standard bioptome (RVEmBxBT; n=24) or by sharp dissection (RVEmBxSD; n=40). Hematoxylin-eosin stained sections of RV and LV cross section and RVEmBxs were compared in a blinded fashion. Characteristics of delayed xenograft rejection (DXR) and a global assessment of ischemia, were scored from 0 to 4 based on the percentage of myocardium involved (0 = 0%, 1=1−25%, 2 = 26−50%, 3 = 51−75%, 4 = 76−100%). Results Median graft survival was 30 days (range 3–137). Linear regression analysis of histology scores demonstrated that both RVEmBxBT and RVEmBxSD equally represented the histology of RV cross section. Global ischemic injury was strongly correlated between RV and RVEmBx (R2=0.84) and between RV and LV cross sections (R2=0.84). Individual characteristics of DXR showed no significant variation between RV and RVEmBx or between RV and LV (p<0.05). Conclusions These results indicate that DXR is a widespread process involving both right and left ventricles similarly. This study shows that histologic assessment of RVEmBx specimens is an effective method for the monitoring of DXR after cardiac xenotransplantation. PMID:17919623

Imaging the Material Properties of Bone Specimens using Reflection-Based Infrared Microspectroscopy

PubMed Central

Acerbo, Alvin S.; Carr, G. Lawrence; Judex, Stefan; Miller, Lisa M.

2012-01-01

Fourier Transform InfraRed Microspectroscopy (FTIRM) is a widely used method for mapping the material properties of bone and other mineralized tissues, including mineralization, crystallinity, carbonate substitution, and collagen cross-linking. This technique is traditionally performed in a transmission-based geometry, which requires the preparation of plastic-embedded thin sections, limiting its functionality. Here, we theoretically and empirically demonstrate the development of reflection-based FTIRM as an alternative to the widely adopted transmission-based FTIRM, which reduces specimen preparation time and broadens the range of specimens that can be imaged. In this study, mature mouse femurs were plastic-embedded and longitudinal sections were cut at a thickness of 4 μm for transmission-based FTIRM measurements. The remaining bone blocks were polished for specular reflectance-based FTIRM measurements on regions immediately adjacent to the transmission sections. Kramers-Kronig analysis of the reflectance data yielded the dielectric response from which the absorption coefficients were directly determined. The reflectance-derived absorbance was validated empirically using the transmission spectra from the thin sections. The spectral assignments for mineralization, carbonate substitution, and collagen cross-linking were indistinguishable in transmission and reflection geometries, while the stoichiometric/non-stoichiometric apatite crystallinity parameter shifted from 1032 / 1021 cm−1 in transmission-based to 1035 / 1025 cm−1 in reflection-based data. This theoretical demonstration and empirical validation of reflection-based FTIRM eliminates the need for thin sections of bone and more readily facilitates direct correlations with other methods such nanoindentation and quantitative backscatter electron imaging (qBSE) from the same specimen. It provides a unique framework for correlating bone’s material and mechanical properties. PMID:22455306

Three dimensional X-ray Diffraction Contrast Tomography Reconstruction of Polycrystalline Strontium Titanate during Sintering and Electron Backscatter Diffraction Validation

NASA Astrophysics Data System (ADS)

Syha, M.; Rheinheimer, W.; Loedermann, B.; Graff, A.; Trenkle, A.; Baeurer, M.; Weygand, D.; Ludwig, W.; Gumbsch, P.

The microstructural evolution of polycrystalline strontium titanate was investigated in three dimensions (3D) using X-ray diffraction contrast tomography (DCT) before and after ex-situ annealing at 1600°C. Post-annealing, the specimen was additionally subjected to phase contrast tomography (PCT) in order to finely resolve the porosities. The resulting microstructure reconstructions were studied with special emphasis on morphology and interface orientation during microstructure evolution. Subsequently, cross-sections of the specimen were studied using electron backscatter diffraction (EBSD). Corresponding cross-sections through the 3D reconstruction were identified and the quality of the reconstruction is validated with special emphasis on the spatial resolution at the grain boundaries, the size and location of pores contained in the material and the accuracy of the orientation determination.

Thermomechanical testing of high-temperature composites - Thermomechanical fatigue (TMF) behavior of SiC(SCS-6)/Ti-15-3

NASA Technical Reports Server (NTRS)

Castelli, Michael G.; Bartolotta, Paul; Ellis, John R.

1992-01-01

Thermomechanical testing techniques recently developed for monolithic structural alloys were successfully extended to continuous fiber reinforced composite materials in plate form. The success of this adaptation was verified on a model metal matrix composite (MMC) material, namely SiC(SCS-6)/Ti-15V-3Cr-3Al-3Sn. Effects of heating system type and specimen preparation are also addressed. Cyclic lives determined under full thermomechanical conditions were shown to be significantly reduced from those obtained under comparable isothermal and in-phase bi-thermal conditions. Fractography and metallography from specimens subjected to isothermal, out-of-phase and in-phase conditions reveal distinct differences in damage-failure modes. Isothermal metallography revealed extensive matrix cracking associated with fiber damage throughout the entire cross-section of the specimen. Out-of-phase metallography revealed extensive matrix damage associated with minimal (if any) fiber cracking. However, the damage was located exclusively at surface and near-surface locations. In-phase conditions produced extensive fiber cracking throughout the entire cross-section, associated with minimal (if any) matrix damage.

Thermomechanical testing techniques for high-temparature composites: TMF behavior of SiC(SCS-6)/Ti-15-3

NASA Technical Reports Server (NTRS)

Castelli, Michael G.; Ellis, J. Rodney; Bartolotta, Paul A.

1990-01-01

Thermomechanical testing techniques recently developed for monolithic structural alloys were successfully extended to continuous fiber reinforced composite materials in plate form. The success of this adaptation was verified on a model metal matrix composite (MMC) material, namely SiC(SCS-6)/Ti-15V-3Cr-3Al-3Sn. Effects of heating system type and specimen preparation are also addressed. Cyclic lives determined under full thermo-mechanical conditions were shown to be significantly reduced from those obtained under comparable isothermal and in-phase bi-thermal conditions. Fractography and metallography from specimens subjected to isothermal, out-of-phase and in-phase conditions reveal distinct differences in damage-failure modes. Isothermal metallography revealed extensive matrix cracking associated with fiber damage throughout the entire cross-section of the specimen. Out-of-phase metallography revealed extensive matrix damage associated with minimal (if any) fiber cracking. However, the damage was located exclusively at surface and near-surface locations. In-phase conditions produced extensive fiber cracking throughout the entire cross-section, associated with minimal (if any) matrix damage.

Backscattering and extinction cross sections of two swimbladdered fishes at the lowest resonance, as modeled by the boundary-element method

NASA Astrophysics Data System (ADS)

Foote, Kenneth G.; Francis, David T. I.

2003-04-01

The boundary-element method has been applied to backscattering and extinction of sound by swimbladdered fish at the lowest, breathing-mode resonance. Corresponding cross sections have been computed for specimens of two representative kinds of swimbladder-bearing fish, namely physostomes and physoclists, which, respectively, possess and lack an external duct. The respective fishes are herring (Clupea harengus) and pollack (Pollachius pollachius), for which swimbladder morphometric data are available. The depth dependences of the cross sections are computed over the range 0-500 m. Comparisons are made with measurements and other modeled results for a number of species. [Work supported by ONR.

Compliance and stress intensity coefficients for short bar specimens with chevron notches

NASA Technical Reports Server (NTRS)

Munz, D.; Bubsey, R. T.; Srawley, J. E.

1980-01-01

For the determination of fracture toughness especially with brittle materials, a short bar specimen with rectangular cross section and chevron notch can be used. As the crack propagates from the tip of the triangular notch, the load increases to a maximum then decreases. To obtain the relation between the fracture toughness and maximum load, calculations of Srawley and Gross for specimens with a straight-through crack were applied to the specimens with chevron notches. For the specimens with a straight-through crack, an analytical expression was obtained. This expression was used for the calculation of the fracture toughness versus maximum load relation under the assumption that the change of the compliance with crack length for the specimen with a chevron notch is the same as for a specimen with a straight-through crack.

Tensile Properties of the Deep Transverse Metatarsal Ligament in Hallux Valgus: A CONSORT-Compliant Article.

PubMed

Abdalbary, Sahar Ahmed; Elshaarawy, Ehab A A; Khalid, Bahaa E A

2016-02-01

The deep transverse metatarsal ligament (DTML) connects the neighboring2 metatarsal heads and is one of the stabilizers connecting the lateral sesamoid and second metatarsal head. In this study, we aimed to determine the tensile properties of the DTML in normal specimens and to compare these results with hallux valgus specimens. We hypothesized that the tensile properties of the DTML would be different between the 2 groups of specimens.The DTML in the first interspace was dissected from 12 fresh frozen human cadaveric specimens. Six cadavers had bilateral hallux valgus and the other 6 cadavers had normal feet. The initial length (L0) and cross-sectional area (A0) of the DTML were measured using a digital caliper, and tensile tests with load failure were performed using a material testing machine.There were significant between-groups differences in the initial length (L0) P = 0.009 and cross-sectional area (A0) of the DTML P = 0.007. There were also significant between-groups differences for maximum force (N) P = 0.004, maximum distance (mm) P = 0.005, maximum stress (N/mm) P = 0.003, and maximum strain (%) P = 0.006.The DTML is an anatomical structure for which the tensile properties differ in hallux valgus.

Endoanal MRI of the anal sphincter complex: correlation with cross-sectional anatomy and histology.

PubMed Central

Hussain, S M; Stoker, J; Zwamborn, A W; Den Hollander, J C; Kuiper, J W; Entius, C A; Laméris, J S

1996-01-01

The purpose of this study was to correlate the in vivo endoanal MRI findings of the anal sphincter with the cross-sectional anatomy and histology. Fourteen patients with rectal tumours were examined with a rigid endoanal MR coil before undergoing abdominoperineal resection. In addition, 12 cadavers were used to obtain cross-sectional anatomical sections. The images were correlated with the histology and anatomy of the resected rectal specimens as well as with the cross-sectional anatomical sections of the 12 cadavers. The findings in 8 patients, 11 rectal preparations, and 10 cadavers, could be compared. In these cases, there was an excellent correlation between endoanal MRI and the cross-sectional cadaver anatomy and histology. With endoanal MRI, all muscle layers of the anal canal wall, comprising the internal anal sphincter, longitudinal muscle, the external anal sphincter and the puborectalis muscle were clearly visible. The levator ani muscle and ligamentous attachments were also well demonstrated. The perianal anatomical spaces, containing multiple septae, were clearly visible. In conclusion, endoanal MRI is excellent for visualising the anal sphincter complex and the findings show a good correlation with the cross-sectional anatomy and histology. Images Fig. 1 Fig. 2 PMID:8982844

Human aflatoxin exposure in Kenya, 2007: a cross-sectional study

PubMed Central

Yard, Ellen E.; Daniel, Johnni H.; Lewis, Lauren S.; Rybak, Michael E.; Paliakov, Ekaterina M.; Kim, Andrea A.; Montgomery, Joel M.; Bunnell, Rebecca; Abudo, Mamo Umuro; Akhwale, Willis; Breiman, Robert F.; Sharif, Shahnaaz K.

2013-01-01

Aflatoxins contaminate approximately 25% of agricultural products worldwide. They can cause liver failure and liver cancer. Kenya has experienced multiple aflatoxicosis outbreaks in recent years, often resulting in fatalities. However, the full extent of aflatoxin exposure in Kenya has been unknown. Our objective was to quantify aflatoxin exposure across Kenya. We analysed aflatoxin levels in serum specimens from the 2007 Kenya AIDS Indicator Survey – a nationally representative, cross-sectional serosurvey. KAIS collected 15,853 blood specimens. Of the 3180 human immunodeficiency virus-negative specimens with ≥1 mL sera, we randomly selected 600 specimens stratified by province and sex. We analysed serum specimens for aflatoxin albumin adducts by using isotope dilution MS/MS to quantify aflatoxin B1-lysine, and normalised with serum albumin. Aflatoxin concentrations were then compared by demographic, socioeconomic and geographic characteristics. We detected serum aflatoxin B1-lysine in 78% of serum specimens (range =

Heat Treatment Investigation of 4330 Vanadium-Modified Steel

DTIC Science & Technology

1989-08-01

the desired properties, using the results from the tensile and subsized Charpy impact tests on the 1 2-inch-diameter stock our further investigations...for the subsized Charpy specimens is shown graphically in Appendix C as a function of tempering temperature. This data gave a good indication that the... Charpy energy for full-sized specimens (0.394-inch-square cross section) would be near our expected values. Due to the dimensions of the subsized

Cochlear fluid space dimensions for six species derived from reconstructions of three-dimensional magnetic resonance images.

PubMed

Thorne, M; Salt, A N; DeMott, J E; Henson, M M; Henson, O W; Gewalt, S L

1999-10-01

To establish the dimensions and volumes of the cochlear fluid spaces. Fluid space volumes, lengths, and cross-sectional areas were derived for the cochleas from six species: human, guinea pig, bat, rat, mouse, and gerbil. Three-dimensional reconstructions of the fluid spaces were made from magnetic resonance microscopy (MRM) images. Consecutive serial slices composed of isotropic voxels (25 microm3) representing the entire volume of fixed, isolated cochleas were obtained. The boundaries delineating the fluid spaces, including Reissner's membrane, were resolved for all specimens, except for the human, in which Reissner's membrane was not consistently resolved. Three-dimensional reconstructions of the endolymphatic and perilymphatic fluid spaces were generated. Fluid space length and variation of cross-sectional area with distance were derived by an algorithm that followed the midpoint of the space along the length of the spiral. The total volume of each fluid space was derived from a voxel count for each specimen. Length, volume, and cross-sectional areas are provided for six species. In all cases, the length of the endolymphatic fluid space was consistently longer than that of either perilymphatic scala, primarily as a result of a greater radius of curvature. For guinea pig specimens, the measured volumes of the fluid spaces were considerably lower than those suggested by previous reports based on histological data. The quantification of cochlear fluid spaces provided by this study will enable the more accurate calculation of drug and other solute movements in fluids of the inner ear during experimental or clinical manipulations.

Comparative Three-Dimensional Morphology of Baleen: Cross-Sectional Profiles and Volume Measurements Using CT Images.

PubMed

Jensen, Megan M; Saladrigas, Amalia H; Goldbogen, Jeremy A

2017-11-01

Baleen whales are obligate filter feeders, straining prey-laden seawater through racks of keratinized baleen plates. Despite the importance of baleen to the ecology and natural history of these animals, relatively little work has been done on baleen morphology, particularly with regard to the three-dimensional morphology and structure of baleen. We used computed tomography (CT) scanning to take 3D images of six baleen specimens representing five species, including three complete racks. With these images, we described the three-dimensional shape of the baleen plates using cross-sectional profiles from within the gum tissue to the tip of the plates. We also measured the percentage of each specimen that was composed of either keratinized plate material or was void space between baleen plates, and thus available for seawater flow. Baleen plates have a complex three-dimensional structure with curvature that varies across the anterior-posterior, proximal-distal, and medial-lateral (lingual-labial) axes. These curvatures also vary with location along the baleen rack, and between species. Cross-sectional profiles resemble backwards-facing airfoils, and some specimens display S-shaped, or reflexed, camber. Within a baleen specimen, the intra-baleen void volume correlates with the average bristle diameter for a species, suggesting that essentially, thinner plates (with more space between them for flow) have thinner bristles. Both plate curvature and the relative proportions of plate and void volumes are likely to have implications for the mechanics of mysticete filtration, and future studies are needed to determine the particular functions of these morphological characters. Anat Rec, 300:1942-1952, 2017. © 2017 The Authors The Anatomical Record published by Wiley Periodicals, Inc. on behalf of American Association of Anatomists. © 2017 The Authors The Anatomical Record published by Wiley Periodicals, Inc. on behalf of American Association of Anatomists.

Azimuthally anisotropic hydride lens structures in Zircaloy 4 nuclear fuel cladding: High-resolution neutron radiography imaging and BISON finite element analysis

NASA Astrophysics Data System (ADS)

Lin, Jun-Li; Zhong, Weicheng; Bilheux, Hassina Z.; Heuser, Brent J.

2017-12-01

High-resolution neutron radiography has been used to image bulk circumferential hydride lens particles in unirradiated Zircaloy 4 tubing cross section specimens. Zircaloy 4 is a common light water nuclear reactor (LWR) fuel cladding; hydrogen pickup, hydride formation, and the concomitant effect on the mechanical response are important for LWR applications. Ring cross section specimens with three hydrogen concentrations (460, 950, and 2830 parts per million by weight) and an as-received reference specimen were imaged. Azimuthally anisotropic hydride lens particles were observed at 950 and 2830 wppm. The BISON finite element analysis nuclear fuel performance code was used to model the system elastic response induced by hydride volumetric dilatation. The compressive hoop stress within the lens structure becomes azimuthally anisotropic at high hydrogen concentrations or high hydride phase fraction. This compressive stress anisotropy matches the observed lens anisotropy, implicating the effect of stress on hydride formation as the cause of the observed lens azimuthal asymmetry. The cause and effect relation between compressive stress and hydride lens anisotropy represents an indirect validation of a key BISON output, the evolved hoop stress associated with hydride formation.

Estimating Infection Attack Rates and Severity in Real Time during an Influenza Pandemic: Analysis of Serial Cross-Sectional Serologic Surveillance Data

PubMed Central

Wu, Joseph T.; Ho, Andrew; Ma, Edward S. K.; Lee, Cheuk Kwong; Chu, Daniel K. W.; Ho, Po-Lai; Hung, Ivan F. N.; Ho, Lai Ming; Lin, Che Kit; Tsang, Thomas; Lo, Su-Vui; Lau, Yu-Lung; Leung, Gabriel M.

2011-01-01

Background In an emerging influenza pandemic, estimating severity (the probability of a severe outcome, such as hospitalization, if infected) is a public health priority. As many influenza infections are subclinical, sero-surveillance is needed to allow reliable real-time estimates of infection attack rate (IAR) and severity. Methods and Findings We tested 14,766 sera collected during the first wave of the 2009 pandemic in Hong Kong using viral microneutralization. We estimated IAR and infection-hospitalization probability (IHP) from the serial cross-sectional serologic data and hospitalization data. Had our serologic data been available weekly in real time, we would have obtained reliable IHP estimates 1 wk after, 1–2 wk before, and 3 wk after epidemic peak for individuals aged 5–14 y, 15–29 y, and 30–59 y. The ratio of IAR to pre-existing seroprevalence, which decreased with age, was a major determinant for the timeliness of reliable estimates. If we began sero-surveillance 3 wk after community transmission was confirmed, with 150, 350, and 500 specimens per week for individuals aged 5–14 y, 15–19 y, and 20–29 y, respectively, we would have obtained reliable IHP estimates for these age groups 4 wk before the peak. For 30–59 y olds, even 800 specimens per week would not have generated reliable estimates until the peak because the ratio of IAR to pre-existing seroprevalence for this age group was low. The performance of serial cross-sectional sero-surveillance substantially deteriorates if test specificity is not near 100% or pre-existing seroprevalence is not near zero. These potential limitations could be mitigated by choosing a higher titer cutoff for seropositivity. If the epidemic doubling time is longer than 6 d, then serial cross-sectional sero-surveillance with 300 specimens per week would yield reliable estimates when IAR reaches around 6%–10%. Conclusions Serial cross-sectional serologic data together with clinical surveillance data can allow reliable real-time estimates of IAR and severity in an emerging pandemic. Sero-surveillance for pandemics should be considered. Please see later in the article for the Editors' Summary PMID:21990967

Comparisons of nanoindentation, 3-point bending, and tension tests for orthodontic wires.

PubMed

Iijima, Masahiro; Muguruma, Takeshi; Brantley, William A; Mizoguchi, Itaru

2011-07-01

The purposes of this study were to obtain information about mechanical properties with the nanoindentation test for representative wire alloys and compare the results with conventional mechanical tests. Archwires having 0.016 × 0.022-in cross sections were obtained of 1 stainless steel, 1 cobalt-chromium-nickel, 1 beta-titanium alloy, and 2 nickel-titanium products. Specimens of as-received wires were subjected to nanoindentation testing along the external surfaces and over polished cross sections to obtain values of hardness and elastic modulus. Other specimens of as-received wires were subjected to Vickers hardness, 3-point bending, and tension tests. All testing was performed at 25°C. Differences were found in hardness and elastic modulus obtained with the nanoindentation test at the external and cross-sectioned surfaces and with the conventional mechanical-property tests. Mechanical properties obtained with the nanoindentation test generally varied with indentation depth. The 3 testing methods did not yield identical values of hardness and elastic modulus, although the order among the 5 wire products was the same. Variations in results for the nanoindentation and conventional mechanical property tests can be attributed to the different material volumes sampled, different work-hardening levels, and an oxide layer on the wire surface. Copyright © 2011 American Association of Orthodontists. Published by Mosby, Inc. All rights reserved.

Effect of Reinforcement Architecture on Fracture of Selectively Reinforced Metallic Compact Tension Specimens

NASA Technical Reports Server (NTRS)

Abada, Christopher H.; Farley, Gary L.; Hyer, Michael W.

2006-01-01

A computer-based parametric study of the effect of reinforcement architectures on fracture response of aluminum compact-tension (CT) specimens is performed. Eleven different reinforcement architectures consisting of rectangular and triangular cross-section reinforcements were evaluated. Reinforced specimens produced between 13 and 28 percent higher fracture load than achieved with the non-reinforced case. Reinforcements with blunt leading edges (rectangular reinforcements) exhibited superior performance relative to the triangular reinforcements with sharp leading edges. Relative to the rectangular reinforcements, the most important architectural feature was reinforcement thickness. At failure, the reinforcements carried between 58 and 85 percent of the load applied to the specimen, suggesting that there is considerable load transfer between the base material and the reinforcement.

Two-Dimensional Nonlinear Finite Element Analysis of CMC Microstructures

NASA Technical Reports Server (NTRS)

Mital, Subodh K.; Goldberg, Robert K.; Bonacuse, Peter J.

2011-01-01

Detailed two-dimensional finite element analyses of the cross-sections of a model CVI (chemical vapor infiltrated) SiC/SiC (silicon carbide fiber in a silicon carbide matrix) ceramic matrix composites are performed. High resolution images of the cross-section of this composite material are generated using serial sectioning of the test specimens. These images are then used to develop very detailed finite element models of the cross-sections using the public domain software OOF2 (Object Oriented Analysis of Material Microstructures). Examination of these images shows that these microstructures have significant variability and irregularity. How these variabilities manifest themselves in the variability in effective properties as well as the stress distribution, damage initiation and damage progression is the overall objective of this work. Results indicate that even though the macroscopic stress-strain behavior of various sections analyzed is very similar, each section has a very distinct damage pattern when subjected to in-plane tensile loads and this damage pattern seems to follow the unique architectural and microstructural details of the analyzed sections.

Correlative Magnetic Imaging of Heat-Assisted Magnetic Recording Media in Cross Section Using Lorentz TEM and MFM

DOE PAGES

Kim, Taeho Roy; Phatak, Charudatta; Petford-Long, Amanda K.; ...

2017-10-23

In order to increase the storage density of hard disk drives, a detailed understanding of the magnetic structure of the granular magnetic layer is essential. Here, we demonstrate an experimental procedure of imaging recorded bits on heat-assisted magnetic recording (HAMR) media in cross section using Lorentz transmission electron microscopy (TEM). With magnetic force microscopy and focused ion beam (FIB), we successfully targeted a single track to prepare cross-sectional TEM specimens. Then, we characterized the magnetic structure of bits with their precise location and orientation using Fresnel mode of Lorentz TEM. Here, this method can promote understanding of the correlation betweenmore » bits and their material structure in HAMR media to design better the magnetic layer.« less

Correlative Magnetic Imaging of Heat-Assisted Magnetic Recording Media in Cross Section Using Lorentz TEM and MFM

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

Kim, Taeho Roy; Phatak, Charudatta; Petford-Long, Amanda K.

In order to increase the storage density of hard disk drives, a detailed understanding of the magnetic structure of the granular magnetic layer is essential. Here, we demonstrate an experimental procedure of imaging recorded bits on heat-assisted magnetic recording (HAMR) media in cross section using Lorentz transmission electron microscopy (TEM). With magnetic force microscopy and focused ion beam (FIB), we successfully targeted a single track to prepare cross-sectional TEM specimens. Then, we characterized the magnetic structure of bits with their precise location and orientation using Fresnel mode of Lorentz TEM. Here, this method can promote understanding of the correlation betweenmore » bits and their material structure in HAMR media to design better the magnetic layer.« less

The Cross-Sectional Investigation of Oxide Scale FeCr Alloys and Commercial Ferritic Steel Implanted with Lanthanum and Titanium Dopants after Oxidation Test at 900°C

NASA Astrophysics Data System (ADS)

Saryanto, Hendi; Sebayang, Darwin; Untoro, Pudji; Sujitno, Tjipto

2018-03-01

The cross-sectional examinations of oxide scales formed by oxidation on the surface of FeCr alloys and Ferritic Steel that implanted with lanthanum and titanium dopants were observed and investigated. Scanning electron microscopy (SEM) coupled with energy dispersive X-ray spectroscopy (EDS) has been used to study the cross-sectional oxides produced by specimens after oxidation process. X-ray diffraction (XRD) analysis was used to strengthen the analysis of the oxide scale morphology, oxide phases and oxidation products. Cross-sectional observations show the effectiveness of La implantation for improving thinner and stronger scale/substrate interface during oxidation process. The result shows that the thickness of oxide scales formed on the surface of La implanted FeCr alloy and ferritic steel was found less than 3 μm and 300 μm, respectively. The oxide scale formed on the surface of La implanted specimens consisted roughly of Cr2O3 with a small amount of FeO mixture, which indicates that lanthanum implantation can improve the adherence, reduce the growth of the oxide scale as well as reduce the Cr evaporation. On the other side, the oxide scale formed on the surface of FeCr alloys and ferritic steel that implanted with titanium dopant was thicker, indicating that significant increase in oxidation mass gain. It can be noticed that titanium implantation ineffectively promotes Cr rich oxide. At the same time, the amount of Fe increased and diffused outwards, which caused the formation and rapid growth of FeO.

Determination of fiber volume in graphite/epoxy materials using computer image analysis

NASA Technical Reports Server (NTRS)

Viens, Michael J.

1990-01-01

The fiber volume of graphite/epoxy specimens was determined by analyzing optical images of cross sectioned specimens using image analysis software. Test specimens were mounted and polished using standard metallographic techniques and examined at 1000 times magnification. Fiber volume determined using the optical imaging agreed well with values determined using the standard acid digestion technique. The results were found to agree within 5 percent over a fiber volume range of 45 to 70 percent. The error observed is believed to arise from fiber volume variations within the graphite/epoxy panels themselves. The determination of ply orientation using image analysis techniques is also addressed.

Front-Loading Sputum Microscopy Services: An Opportunity to Optimise Smear-Based Case Detection of Tuberculosis in High Prevalence Countries

PubMed Central

Ramsay, Andy; Yassin, Mohammed Ahmed; Cambanis, Alexis; Hirao, Susumu; Almotawa, Ahmad; Gammo, Mohamed; Lawson, Lovett; Arbide, Izabel; Al-Aghbari, Nasher; Al-Sonboli, Najla; Sherchand, Jeevan Bahadur; Gauchan, Punita; Cuevas, Luis Eduardo

2009-01-01

Setting. Ethiopia, Nepal, Nigeria, and Yemen. Objective. To reduce the time to complete sputum microscopy. Design. Cross-sectional surveys enrolling 923 patients with chronic cough in the 4 countries and using similar protocols. Spot-morning-spot sputum specimens were collected. An additional sputum specimen (Xspot) was collected one hour after the first, and the yields of the first two or the three specimens collected as spot-morning-spot or spot-Xspot-morning were compared. Results. 216 patients had ≥ one positive smear. 210 (97%) were identified by the spot-morning-spot, and 210 (97%) were identified by the spot-Xspot-morning specimens, with 203 and 200 identified by the first 2 specimens of each approach, respectively. Neither difference was significant. Conclusions. The time to complete smear microscopy could be reduced. PMID:20309419

Three-dimensional finite-element elastic analysis of a thermally cycled single-edge wedge geometry specimen

NASA Technical Reports Server (NTRS)

Bizon, P. T.; Hill, R. J.; Guilliams, B. P.; Drake, S. K.; Kladden, J. L.

1979-01-01

An elastic stress analysis was performed on a wedge specimen (prismatic bar with single-wedge cross section) subjected to thermal cycles in fluidized beds. Seven different combinations consisting of three alloys (NASA TAZ-8A, 316 stainless steel, and A-286) and four thermal cycling conditions were analyzed. The analyses were performed as a joint effort of two laboratories using different models and computer programs (NASTRAN and ISO3DQ). Stress, strain, and temperature results are presented.

Steel-reinforced concrete-filled steel tubular columns under axial and lateral cyclic loading

NASA Astrophysics Data System (ADS)

Farajpourbonab, Ebrahim; Kute, Sunil Y.; Inamdar, Vilas M.

2018-03-01

SRCFT columns are formed by inserting a steel section into a concrete-filled steel tube. These types of columns are named steel-reinforced concrete-filled steel tubular (SRCFT) columns. The current study aims at investigating the various types of reinforcing steel section to improve the strength and hysteresis behavior of SRCFT columns under axial and lateral cyclic loading. To attain this objective, a numerical study has been conducted on a series of composite columns. First, FEM procedure has been verified by the use of available experimental studies. Next, eight composite columns having different types of cross sections were analyzed. For comparison purpose, the base model was a CFT column used as a benchmark specimen. Nevertheless, the other specimens were SRCFT types. The results indicate that reinforcement of a CFT column through this method leads to enhancement in load-carrying capacity, enhancement in lateral drift ratio, ductility, preventing of local buckling in steel shell, and enhancement in energy absorption capacity. Under cyclic displacement history, it was observed that the use of cross-shaped reinforcing steel section causes a higher level of energy dissipation and the moment of inertia of the reinforcing steel sections was found to be the most significant parameter affecting the hysteresis behavior of SRCFT columns.

Measuring Growth on a Museum Field Trip: Dinosaur Bones and Tree Cross Sections

ERIC Educational Resources Information Center

Sedzielarz, Maija; Robinson, Christopher

2007-01-01

The MathPacks program at the Science Museum of Minnesota provides students with in-depth understanding of real-world applications of mathematics and science. Students measure museum specimens and investigate ratios, patterns, and mapping while simulating the work of scientists.

Pyramidal lobe of the thyroid gland and the thyroglossal duct remnant: a study using human fetal sections.

PubMed

Takanashi, Yoshitaka; Honkura, Yohei; Rodriguez-Vazquez, Jose Francisco; Murakami, Gen; Kawase, Tetsuaki; Katori, Yukio

2015-01-01

To investigate developmental changes in the thyroglossal duct, we observed serial sagittal sections of eight embryos (crown-rump length (CRL) 6-12 mm; approximately 5-6 weeks of gestation) as well as serial horizontal or cross-sections of 70 embryos and fetuses (CRL 15-110 mm; 6-15 weeks). In the sagittal sections, the thyroglossal duct was identified as a small sheet or mass of relatively large cells with vacuolization anterior, superior or inferior to the fourth pharyngeal arch artery. However, we found no continuous duct-like structure that reached the thyroid gland. Thus, previous classical schemes might have overestimated the continuity of the duct. Among cross-sections of 70 specimens, we found the thyroglossal duct remnant in only two specimens (CRL 15 mm and 100 mm), in contrast to the pyramidal lobe, which was seen in one-third of the specimens. The duct remnant ran downward along the lateral edge of the hyoid body to reach the anterior aspect of the thyroid cartilage. However, the connection between the pyramidal lobe and the duct remnant was interrupted by the anterior cervical muscles. Therefore, it was unlikely that the thyroglossal duct remnant would more frequently be evident in fetuses than in adults. The highly tortuous course of the duct along the lingual aspect of the hyoid body, which has been reported previously, appeared to become established near term. Descent of the thyroid gland was not evident after the CRL 20 mm stage (6 weeks): the gland appeared to retain its position at the level of the third-sixth cervical vertebrae. Copyright © 2014 Elsevier GmbH. All rights reserved.

Integrated light-sheet imaging and flow-based enquiry (iLIFE) system for 3D in-vivo imaging of multicellular organism

NASA Astrophysics Data System (ADS)

Rasmi, Chelur K.; Padmanabhan, Sreedevi; Shirlekar, Kalyanee; Rajan, Kanhirodan; Manjithaya, Ravi; Singh, Varsha; Mondal, Partha Pratim

2017-12-01

We propose and demonstrate a light-sheet-based 3D interrogation system on a microfluidic platform for screening biological specimens during flow. To achieve this, a diffraction-limited light-sheet (with a large field-of-view) is employed to optically section the specimens flowing through the microfluidic channel. This necessitates optimization of the parameters for the illumination sub-system (illumination intensity, light-sheet width, and thickness), microfluidic specimen platform (channel-width and flow-rate), and detection sub-system (camera exposure time and frame rate). Once optimized, these parameters facilitate cross-sectional imaging and 3D reconstruction of biological specimens. The proposed integrated light-sheet imaging and flow-based enquiry (iLIFE) imaging technique enables single-shot sectional imaging of a range of specimens of varying dimensions, ranging from a single cell (HeLa cell) to a multicellular organism (C. elegans). 3D reconstruction of the entire C. elegans is achieved in real-time and with an exposure time of few hundred micro-seconds. A maximum likelihood technique is developed and optimized for the iLIFE imaging system. We observed an intracellular resolution for mitochondria-labeled HeLa cells, which demonstrates the dynamic resolution of the iLIFE system. The proposed technique is a step towards achieving flow-based 3D imaging. We expect potential applications in diverse fields such as structural biology and biophysics.

The Effects of Specimen Geometry and Size on the Dynamic Failure of Aluminum Alloy 2219-T8 Under Impact Loading

NASA Astrophysics Data System (ADS)

Bolling, Denzell Tamarcus

A significant amount of research has been devoted to the characterization of new engineering materials. Searching for new alloys which may improve weight, ultimate strength, or fatigue life are just a few of the reasons why researchers study different materials. In support of that mission this study focuses on the effects of specimen geometry and size on the dynamic failure of AA2219 aluminum alloy subjected to impact loading. Using the Split Hopkinson Pressure Bar (SHPB) system different geometric samples including cubic, rectangular, cylindrical, and frustum samples are loaded at different strain rates ranging from 1000s-1 to 6000s-1. The deformation properties, including the potential for the formation of adiabatic shear bands, of the different geometries are compared. Overall the cubic geometry achieves the highest critical strain and the maximum stress values at low strain rates and the rectangular geometry has the highest critical strain and the maximum stress at high strain rates. The frustum geometry type consistently achieves the lowest the maximum stress value compared to the other geometries under equal strain rates. All sample types clearly indicated susceptibility to strain localization at different locations within the sample geometry. Micrograph analysis indicated that adiabatic shear band geometry was influenced by sample geometry, and that specimens with a circular cross section are more susceptible to shear band formation than specimens with a rectangular cross section.

Assessing the feasibility of yttria-stabilized zirconia in novel designs as mandibular anterior fixed lingual retention following orthodontic treatment

NASA Astrophysics Data System (ADS)

Stout, Matthew

The purpose of this study is to explore the feasibility of yttria-stabilized zirconia (Y-TZP) in fixed lingual retention as an alternative to stainless steel. Exploratory Y-TZP specimens were milled to establish design parameters. Next, specimens were milled according to ASTM standard C1161-13 and subjected to four-point flexural test to determine materials properties. Finite Element (FE) Analysis was employed to evaluate nine novel cross-sectional designs and compared to stainless steel wire. Each design was analyzed under the loading conditions to determine von Mises and bond stress. The most promising design was fabricated to assess accuracy and precision of current CAD/CAM milling technology. The superior design had a 1.0 x 0.5 mm semi-elliptical cross section and was shown to be fabricated reliably. Overall, the milling indicated a maximum percent standard deviation of 9.3 and maximum percent error of 13.5 with a cost of $30 per specimen. Y-TZP can be reliably milled to dimensions comparable to currently available metallic retainer wires. Further research is necessary to determine the success of bonding protocol and clinical longevity of Y-TZP fixed retainers. Advanced technology is necessary to connect the intraoral scan to an aesthetic and patient-specific Y-TZP fixed retainer.

Determination of Poisson Ratio of Bovine Extraocular Muscle by Computed X-Ray Tomography

PubMed Central

Kim, Hansang; Yoo, Lawrence; Shin, Andrew; Demer, Joseph L.

2013-01-01

The Poisson ratio (PR) is a fundamental mechanical parameter that approximates the ratio of relative change in cross sectional area to tensile elongation. However, the PR of extraocular muscle (EOM) is almost never measured because of experimental constraints. The problem was overcome by determining changes in EOM dimensions using computed X-ray tomography (CT) at microscopic resolution during tensile elongation to determine transverse strain indicated by the change in cross-section. Fresh bovine EOM specimens were prepared. Specimens were clamped in a tensile fixture within a CT scanner (SkyScan, Belgium) with temperature and humidity control and stretched up to 35% of initial length. Sets of 500–800 contiguous CT images were obtained at 10-micron resolution before and after tensile loading. Digital 3D models were then built and discretized into 6–8-micron-thick elements. Changes in longitudinal thickness of each microscopic element were determined to calculate strain. Green's theorem was used to calculate areal strain in transverse directions orthogonal to the stretching direction. The mean PR from discretized 3D models for every microscopic element in 14 EOM specimens averaged 0.457 ± 0.004 (SD). The measured PR of bovine EOM is thus near the limit of incompressibility. PMID:23484091

Fracture Response Enhancement Of Aluminum Using In-Situ Selective Reinforcement

NASA Technical Reports Server (NTRS)

Abada, Christopher H.; Farley, Gary L.; Hyer, Michael W.

2006-01-01

A computer-based parametric study of the effect of reinforcement architectures on fracture response of aluminum compact-tension (CT) specimens is performed. Eleven different reinforcement architectures consisting of rectangular and triangular cross-section reinforcements were evaluated. Reinforced specimens produced between 13 and 28 percent higher fracture load than achieved with the unreinforced case. Reinforcements with blunt leading edges (rectangular reinforcements) exhibited superior performance relative to the triangular reinforcements with sharp leading edges. Relative to the rectangular reinforcements, the most important architectural feature was reinforcement thickness. At failure, the reinforcements carried between 58 and 85 percent of the load applied to the specimen, suggesting that there is considerable load transfer between the base material and the reinforcement.

Ultrasonic tomography for in-process measurements of temperature in a multi-phase medium

DOEpatents

Beller, Laurence S.

1993-01-01

A method and apparatus for the in-process measurement of internal particulate temperature utilizing ultrasonic tomography techniques to determine the speed of sound through a specimen material. Ultrasonic pulses are transmitted through a material, which can be a multi-phase material, over known flight paths and the ultrasonic pulse transit times through all sectors of the specimen are measured to determine the speed of sound. The speed of sound being a function of temperature, it is possible to establish the correlation between speed of sound and temperature, throughout a cross-section of the material, which correlation is programmed into a computer to provide for a continuous in-process measurement of temperature throughout the specimen.

A Novel Three-Dimensional Tool for Teaching Human Neuroanatomy

ERIC Educational Resources Information Center

Estevez, Maureen E.; Lindgren, Kristen A.; Bergethon, Peter R.

2010-01-01

Three-dimensional (3D) visualization of neuroanatomy can be challenging for medical students. This knowledge is essential in order for students to correlate cross-sectional neuroanatomy and whole brain specimens within neuroscience curricula and to interpret clinical and radiological information as clinicians or researchers. This study implemented…

Determination of necking time in tensile test specimens, under high-temperature creep conditions, subjected to distribution of stresses over the cross-section

NASA Astrophysics Data System (ADS)

Lokoshchenko, A.; Teraud, W.

2018-04-01

The work describes an experimental research of creep of cylindrical tensile test specimens made of aluminum alloy D16T at a constant temperature of 400°C. The issue to be examined was the necking at different values of initial tensile stresses. The use of a developed noncontacting measuring system allowed us to see variations in the specimen shape and to estimate the true stress in various times. Based on the obtained experimental data, several criteria were proposed for describing the point of time at which the necking occurs (necking point). Calculations were carried out at various values of the parameters in these criteria. The relative interval of deformation time in which the test specimen is uniformly stretched was also determined.

Microstructures of plasma-sprayed hydroxyapatite-coated Ti-6Al-4V dental implants.

PubMed

Tufekci, E; Brantley, W A; Mitchell, J C; McGlumphy, E A

1997-01-01

The purpose of this study was to investigate the microstructure of plasma-sprayed hydroxyapatite coatings and the elemental composition near the coating-substrate interface for two commercial implants, using the scanning electron microscope. Both coating surfaces and cross-sectioned specimens were examined. The results indicated that while the surface microstructures of both implants were consistent with the plasma-spraying process, the scale of the constituents was much finer for one product. In cross-section, both coatings exhibited minimal porosity and intimate contact with the titanium alloy substrate. It was found that limited interdiffusion of titanium and calcium occurred near the interface.

Three-Dimensional Numerical Simulation on Triaxial Failure Mechanical Behavior of Rock-Like Specimen Containing Two Unparallel Fissures

NASA Astrophysics Data System (ADS)

Huang, Yan-Hua; Yang, Sheng-Qi; Zhao, Jian

2016-12-01

A three-dimensional particle flow code (PFC3D) was used for a systematic numerical simulation of the strength failure and cracking behavior of rock-like material specimens containing two unparallel fissures under conventional triaxial compression. The micro-parameters of the parallel bond model were first calibrated using the laboratory results of intact specimens and then validated from the experimental results of pre-fissured specimens under triaxial compression. Numerically simulated stress-strain curves, strength and deformation parameters and macro-failure modes of pre-fissured specimens were all in good agreement with the experimental results. The relationship between stress and the micro-crack numbers was summarized. Crack initiation, propagation and coalescence process of pre-fissured specimens were analyzed in detail. Finally, horizontal and vertical cross sections of numerical specimens were derived from PFC3D. A detailed analysis to reveal the internal damage behavior of rock under triaxial compression was carried out. The experimental and simulated results are expected to improve the understanding of the strength failure and cracking behavior of fractured rock under triaxial compression.

Probing insect backscatter cross section and melanization using kHz optical remote detection system

NASA Astrophysics Data System (ADS)

Gebru, Alem; Brydegaard, Mikkel; Rohwer, Erich; Neethling, Pieter

2017-01-01

A kHz optical remote sensing system is implemented to determine insect melanization features. This is done by measuring the backscatter signal in the visible and near-infrared (VIS-NIR) and short-wave infrared (SWIR) in situ. It is shown that backscatter cross section in the SWIR is insensitive to melanization and absolute melanization can be derived from the ratio of backscatter cross section of different bands (SWIR/VIS-NIR). We have shown that reflectance from insect is stronger in the SWIR as compared to NIR and VIS. This reveals that melanization plays a big role to determine backscatter cross section. One can use this feature as a tool to improve insect species and age classification. To support the findings, we illustrated melanization feature using three different insects [dead, dried specimens of snow white moth (Spilosoma genus), fox moth (Macrothylacia), and leather beetle (Odontotaenius genus)]. It is shown that reflectance from the leather beetle in the VIS and NIR is more affected by melanization as compared with snow white moth.

Effect of growth ring orientation and placement of earlywood and latewood on MOE and MOR of very-small clear Douglas-fir beams.

Treesearch

Amy T. Grotta; Robert J. Leichti; Barbara L. Gartner; G.R. Johnson

2005-01-01

ASTM standard sizes for bending tests (either 50 x 50 mm or 25 x 25 mm in cross-section) are not always suitable for research purposes that characterize smaller sections of wood. Moreover, the ASTM standards specify loading the sample on the longitudinal-tangential surface. If specimens are small enough, then the effects of both growth-ring orientation and whether...

A study on ground truth data for impact damaged polymer matrix composites

NASA Astrophysics Data System (ADS)

Wallentine, Sarah M.; Uchic, Michael D.

2018-04-01

This study presents initial results toward correlative characterization of barely-visible impact damage (BVID) in unidirectional carbon fiber reinforced polymer matrix composite laminate plates using nondestructive ultrasonic testing (UT) and destructive serial sectioning microscopy. To produce damage consistent with BVID, plates were impacted using an instrumented drop-weight tower with pneumatic anti-rebound brake. High-resolution, normal-incidence, single-sided, pulse-echo, immersion UT scans were performed to verify and map internal damage after impact testing. UT C-scans were registered to optical images of the specimen via landmark registration and the use of an affine transformation, allowing location of internal damage in reference to the overall plate and enabling specimen preparation for subsequent serial sectioning. The impact-damaged region was extracted from each plate, prepared and mounted for materialographic sectioning. A modified RoboMet.3D version 2 was employed for serial sectioning and optical microscopy characterization of the impact damaged regions. Automated montage capture of sub-micron resolution, bright-field reflection, 12-bit monochrome optical images was performed over the entire specimen cross-section. These optical images were post- processed to produce 3D data sets, including segmentation to improve visualization of damage features. Impact-induced delaminations were analyzed and characterized using both serial sectioning and ultrasonic methods. Those results and conclusions are presented, as well as future direction of the current study.

Ultrasonic tomography for in-process measurements of temperature in a multi-phase medium

DOEpatents

Beller, L.S.

1993-01-26

A method and apparatus are described for the in-process measurement of internal particulate temperature utilizing ultrasonic tomography techniques to determine the speed of sound through a specimen material. Ultrasonic pulses are transmitted through a material, which can be a multi-phase material, over known flight paths and the ultrasonic pulse transit times through all sectors of the specimen are measured to determine the speed of sound. The speed of sound being a function of temperature, it is possible to establish the correlation between speed of sound and temperature, throughout a cross-section of the material, which correlation is programmed into a computer to provide for a continuous in-process measurement of temperature throughout the specimen.

Imaging and elemental mapping of biological specimens with a dual-EDS dedicated scanning transmission electron microscope

PubMed Central

Wu, J.S.; Kim, A. M.; Bleher, R.; Myers, B.D.; Marvin, R. G.; Inada, H.; Nakamura, K.; Zhang, X.F.; Roth, E.; Li, S.Y.; Woodruff, T. K.; O'Halloran, T. V.; Dravid, Vinayak P.

2013-01-01

A dedicated analytical scanning transmission electron microscope (STEM) with dual energy dispersive spectroscopy (EDS) detectors has been designed for complementary high performance imaging as well as high sensitivity elemental analysis and mapping of biological structures. The performance of this new design, based on a Hitachi HD-2300A model, was evaluated using a variety of biological specimens. With three imaging detectors, both the surface and internal structure of cells can be examined simultaneously. The whole-cell elemental mapping, especially of heavier metal species that have low cross-section for electron energy loss spectroscopy (EELS), can be faithfully obtained. Optimization of STEM imaging conditions is applied to thick sections as well as thin sections of biological cells under low-dose conditions at room- and cryogenic temperatures. Such multimodal capabilities applied to soft/biological structures usher a new era for analytical studies in biological systems. PMID:23500508

Develop a new testing and evaluation protocol to assess flexbase performance using strength of soil binder.

DOT National Transportation Integrated Search

2008-01-01

This research involved a detailed laboratory study of a new test method for evaluating road base materials based on : the strength of the soil binder. In this test method, small test specimens (5.0in length and 0.75in square cross : section) of binde...

Accuracy verification of magnetic resonance imaging (MRI) technology for lower-limb prosthetic research: utilising animal soft tissue specimen and common socket casting materials.

PubMed

Safari, Mohammad Reza; Rowe, Philip; Buis, Arjan

2012-01-01

Lower limb prosthetic socket shape and volume consistency can be quantified using MRI technology. Additionally, MRI images of the residual limb could be used as an input data for CAD-CAM technology and finite element studies. However, the accuracy of MRI when socket casting materials are used has to be defined. A number of six, 46 mm thick, cross-sections of an animal leg were used. Three specimens were wrapped with Plaster of Paris (POP) and the other three with commercially available silicone interface liner. Data was obtained by utilising MRI technology and then the segmented images compared to corresponding calliper measurement, photographic imaging, and water suspension techniques. The MRI measurement results were strongly correlated with actual diameter, surface area, and volume measurements. The results show that the selected scanning parameters and the semiautomatic segmentation method are adequate enough, considering the limit of clinical meaningful shape and volume fluctuation, for residual limb volume and the cross-sectional surface area measurements.

Accuracy Verification of Magnetic Resonance Imaging (MRI) Technology for Lower-Limb Prosthetic Research: Utilising Animal Soft Tissue Specimen and Common Socket Casting Materials

PubMed Central

Safari, Mohammad Reza; Rowe, Philip; Buis, Arjan

2012-01-01

Lower limb prosthetic socket shape and volume consistency can be quantified using MRI technology. Additionally, MRI images of the residual limb could be used as an input data for CAD-CAM technology and finite element studies. However, the accuracy of MRI when socket casting materials are used has to be defined. A number of six, 46 mm thick, cross-sections of an animal leg were used. Three specimens were wrapped with Plaster of Paris (POP) and the other three with commercially available silicone interface liner. Data was obtained by utilising MRI technology and then the segmented images compared to corresponding calliper measurement, photographic imaging, and water suspension techniques. The MRI measurement results were strongly correlated with actual diameter, surface area, and volume measurements. The results show that the selected scanning parameters and the semiautomatic segmentation method are adequate enough, considering the limit of clinical meaningful shape and volume fluctuation, for residual limb volume and the cross-sectional surface area measurements. PMID:22619599

Digital preservation of anatomical variation: 3D-modeling of embalmed and plastinated cadaveric specimens using uCT and MRI.

PubMed

Moore, Colin W; Wilson, Timothy D; Rice, Charles L

2017-01-01

Anatomy educators have an opportunity to teach anatomical variations as a part of medical and allied health curricula using both cadaveric and three-dimensional (3D) digital models of these specimens. Beyond published cadaveric case reports, anatomical variations identified during routine gross anatomy dissection can be powerful teaching tools and a medium to discuss several anatomical sub-disciplines from embryology to medical imaging. The purpose of this study is to document how cadaveric anatomical variation identified during routine dissection can be scanned using medical imaging techniques to create two-dimensional axial images and interactive 3D models for teaching and learning of anatomical variations. Three cadaveric specimens (2 formalin embalmed, 1 plastinated) depicting anatomical variations and an embryological malformation were scanned using magnetic resonance imaging (MRI) and micro-computed tomography (μCT) for visualization in cross-section and for creation of 3D volumetric models. Results provide educational options to enable visualization and facilitate learning of anatomical variations from cross-sectional scans. Furthermore, the variations can be highlighted, digitized, modeled and manipulated using 3D imaging software and viewed in the anatomy laboratory in conjunction with traditional anatomical dissection. This study provides an example for anatomy educators to teach and describe anatomical variations in the undergraduate medical curriculum. Copyright © 2016 Elsevier GmbH. All rights reserved.

Pigmented lesions of the oral mucosa: A cross-sectional study of 458 histopathological specimens.

PubMed

Tavares, Thalita Soares; Meirelles, Daniela Pereira; de Aguiar, Maria Cássia Ferreira; Caldeira, Patrícia Carlos

2018-06-26

To evaluate clinical, demographic, and histopathological characteristics of pigmented lesions of the oral mucosa. A cross-sectional study was conducted over a 64-year period. Information was collected from medical charts, and all archived histopathologic specimens with diagnoses of any pigmented lesion were retrieved. Statistical analysis was performed using SPSS software. A total of 34,127 archived specimens were reviewed, revealing 458 (1.34%) pigmented lesions, of which 230 were melanocytic and 228 non-melanocytic. Most patients were females (74.2%), white-skinned (49.1%), in the third and seventh decades of life (mean of 45 years). Most lesions were macular (59.8%), followed by plaques and nodules (4.8%), measuring 0-5 mm (41.9%). Cheek mucosa (21.0%), alveolar mucosa (16.6%), and gingiva (11.8%) were the most commonly affected sites. Amalgam tattoo was applied in 212 cases (46.3%), followed by melanotic macule (22.9%) and nevus (20.5%). Other diagnoses included racial pigmentation, exogenous pigmentation, melanotic neuroectodermal tumor of infancy, melanoma, melanocanthoma, smoker's melanosis, and heavy metal pigmentation. Pigmented lesions represent an uncommon diagnosis in oral pathology routines. The most frequent entities are amalgam tattoo, melanotic macule, and nevus. Patients are usually middle-aged women presenting a small, long-lasting, macular lesion on the cheek mucosa. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.

Imaging of fullerene-like structures in CNx thin films by electron microscopy; sample preparation artefacts due to ion-beam milling.

PubMed

Czigány, Zs; Neidhardt, J; Brunell, I F; Hultman, L

2003-04-01

The microstructure of CN(x) thin films, deposited by reactive magnetron sputtering, was investigated by transmission electron microscopy (TEM) at 200kV in plan-view and cross-sectional samples. Imaging artefacts arise in high-resolution TEM due to overlap of nm-sized fullerene-like features for specimen thickness above 5nm. The thinnest and apparently artefact-free areas were obtained at the fracture edges of plan-view specimens floated-off from NaCl substrates. Cross-sectional samples were prepared by ion-beam milling at low energy to minimize sample preparation artefacts. The depth of the ion-bombardment-induced surface amorphization was determined by TEM cross sections of ion-milled fullerene-like CN(x) surfaces. The thickness of the damaged surface layer at 5 degrees grazing incidence was 13 and 10nm at 3 and 0.8keV, respectively, which is approximately three times larger than that observed on Si prepared under the same conditions. The shallowest damage depth, observed for 0.25keV, was less than 1nm. Chemical changes due to N loss and graphitization were also observed by X-ray photoelectron spectroscopy. As a consequence of chemical effects, sputtering rates of CN(x) films were similar to that of Si, which enables relatively fast ion-milling procedure compared to carbon compounds. No electron beam damage of fullerene-like CN(x) was observed at 200kV.

Effect of ion-beam treatment on structure and fracture resistance of 12Cr1MoV steel under static, cyclic and dynamic loading

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

Panin, S. V., E-mail: svp@ispms.tsc.ru; Vlasov, I. V., E-mail: good0@yandex.ru; Sergeev, V. P., E-mail: retc@ispms.tsc.ru

2015-10-27

Features of the structure and properties modification of 12Cr1MoV steel subjected to irradiation by zirconium ion beam have been investigated with the use of optical and electron microscopy as well as microhardness measurement. It has been shown that upon treatment the structure modification occurred across the entire cross-section of specimens with the thickness of 1 mm. Changes in the mechanical properties of these specimens under static, cyclic and impact loading are interpreted in terms of identified structure changes.

Identification of "tumor-associated" nucleolar antigens in human urothelial cancer.

PubMed

Yu, D; Pietro, T; Jurco, S; Scardino, P T

1987-09-01

Nucleoli isolated from HeLa S3 cells were used to produce rabbit antisera capable of binding nucleoli of transitional cell carcinomas (TCCa) of the bladder. Cross-reactivity of the rabbit antiserum with normal nucleoli was reduced by absorption with fetal calf serum, normal human serum, and human placental nucleoli. This antinucleolar antiserum exhibited strong reactivity in immunoperoxidase assays performed on specimens of human bladder cancer. In frozen tissue sections of 24 patients with TCCa and eight individuals without tumor, nucleolar staining was observed in all malignant specimens, but was not observed in seven of the normal specimens. Cytologic examination of bladder washing specimens from 47 normal individuals showed absence of nucleolar staining in 43 (91%) of 47 normal specimens while 12 (86%) of 14 specimens from patients with TCCa were positive. These results suggest that there are antigens associated with the nucleoli of HeLa cells and transitional cell carcinomas which are generally absent (or in low concentration) in normal human urothelial cells, and that antisera to these antigens may be useful in the cytologic diagnosis of human transitional cell carcinoma.

Tissue Microarray Analysis Applied to Bone Diagenesis

PubMed Central

Mello, Rafael Barrios; Silva, Maria Regina Regis; Alves, Maria Teresa Seixas; Evison, Martin Paul; Guimarães, Marco Aurelio; Francisco, Rafaella Arrabaca; Astolphi, Rafael Dias; Iwamura, Edna Sadayo Miazato

2017-01-01

Taphonomic processes affecting bone post mortem are important in forensic, archaeological and palaeontological investigations. In this study, the application of tissue microarray (TMA) analysis to a sample of femoral bone specimens from 20 exhumed individuals of known period of burial and age at death is described. TMA allows multiplexing of subsamples, permitting standardized comparative analysis of adjacent sections in 3-D and of representative cross-sections of a large number of specimens. Standard hematoxylin and eosin, periodic acid-Schiff and silver methenamine, and picrosirius red staining, and CD31 and CD34 immunohistochemistry were applied to TMA sections. Osteocyte and osteocyte lacuna counts, percent bone matrix loss, and fungal spheroid element counts could be measured and collagen fibre bundles observed in all specimens. Decalcification with 7% nitric acid proceeded more rapidly than with 0.5 M EDTA and may offer better preservation of histological and cellular structure. No endothelial cells could be detected using CD31 and CD34 immunohistochemistry. Correlation between osteocytes per lacuna and age at death may reflect reported age-related responses to microdamage. Methodological limitations and caveats, and results of the TMA analysis of post mortem diagenesis in bone are discussed, and implications for DNA survival and recovery considered. PMID:28051148

Grape seed proanthocyanidins increase collagen biodegradation resistance in the dentin/adhesive interface when included in an adhesive.

PubMed

Green, Bradley; Yao, Xiaomei; Ganguly, Arindam; Xu, Changqi; Dusevich, Vladimir; Walker, Mary P; Wang, Yong

2010-11-01

Contemporary methods of dentin bonding could create hybrid layers (HLs) containing voids and exposed, demineralised collagen fibres. Proanthocyanidins (PA) have been shown to cross-link and strengthen demineralised dentin collagen, but their effects on collagen degradation within the HL have not been widely studied. The purpose of this study was to compare the morphological differences of HLs created by BisGMA/HEMA model adhesives with and without the addition of grape seed extract PA under conditions of enzymatic collagen degradation. Model adhesives formulated with and without 5% PA were bonded to the acid etched dentin. 5-μm-thick sections cut from the bonded specimens were stained with Goldner's trichrome. The specimens were then exposed to 0.1% collagenase solution for 0, 1, or 6 days. Following collagenase treatment, the specimens were analysed with SEM/TEM. Staining did not reveal a difference in the HLs created with the two adhesives. SEM showed the presence of intact collagen fibrils in all collagenase treatment conditions for specimens bonded with adhesive containing PA. These integral collagen fibrils were not observed in the specimens bonded with adhesive without PA after the same collagenase treatment. TEM confirmed that the specimens containing PA still showed normal collagen fibril organisation and dimensions after treatment with collagenase solution. In contrast, disorganised collagen fibrils in the interfacial zone lacked the typical cross-banding of normal collagen after collagenase treatment for specimens without PA. The presence of grape seed extract PA in dental adhesives may inhibit the biodegradation of unprotected collagen fibrils within the HL. Copyright © 2010 Elsevier Ltd. All rights reserved.

Specimen dimensions influence the measurement of material properties in tendon fascicles.

PubMed

Legerlotz, Kirsten; Riley, Graham P; Screen, Hazel R C

2010-08-26

Stress, strain and modulus are regularly used to characterize material properties of tissue samples. However, when comparing results from different studies it is evident the reported material properties, particularly failure strains, vary hugely. The aim of our study was to characterize how and why specimen length and cross-sectional area (CSA) appear to influence failure stress, strain and modulus in fascicles from two functionally different tendons. Fascicles were dissected from five rat tails and five bovine foot extensors, their diameters determined by a laser micrometer, and loaded to failure at a range of grip-to-grip lengths. Strain to failure significantly decreased with increasing in specimen length in both rat and bovine fascicles, while modulus increased. Specimen length did not influence failure stress in rat tail fascicles, although in bovine fascicles it was significantly lower in the longer 40 mm specimens compared to 5 and 10mm specimens. The variations in failure strain and modulus with sample length could be predominantly explained by end-effects. However, it was also evident that strain fields along the sample length were highly variable and notably larger towards the ends of the sample than the mid-section even at distances in excess of 5mm from the gripping points. Failure strain, stress and modulus correlated significantly with CSA at certain specimen lengths. Our findings have implications for the mechanical testing of tendon tissue: while it is not always possible to control for fascicle length and/or CSA, these parameters have to be taken into account when comparing samples of different dimensions. 2010 Elsevier Ltd. All rights reserved.

Fracture Strength of Single-Crystal Silicon Carbide Microspecimens at Room and Elevated Temperature

NASA Technical Reports Server (NTRS)

Nemeth, Noel N.; Sharpe, William N., Jr.; Beheim, Glenn M.; Evans, Laura J.; Jadaan, Osama M.

2007-01-01

Three shapes of tensile specimens were tested--curved with a very low stress concentration factor and straight with either a circular hole or an elliptical hole. The nominal thickness was 125 micron with a net section 100 micron wide; the overall length of these microspecimens was 3.1 mm. They were fabricated by an improved version of deep reactive ion etching, which produced specimens with smooth sidewalls and cross-sections having a slightly trapezoidal shape that was exaggerated inside the holes. The novel test setup used a vertical load train extending into a resistance furnace. The specimens had wedge-shaped ends which fit into ceramic grips. The fixed grip was mounted on a ceramic post, and the movable grip was connected to a load cell and actuator outside the furnace with a ceramic-encased nichrome wire. The same arrangement was used for tests at 24 and at 1000 C. The strengths of the curved specimens for two batches of material (made with slightly different processes) were 0.66+/-0.12 GPa and 0.45+/-0.20 GPa respectively at 24 C with identical values at 1000 C. The fracture strengths of the circular-hole and elliptical-hole specimens (computed from the stress concentration factors and measured loads at failure) were approximately 1.2 GPa with slight decreases at the higher temperature. Fractographic examinations showed failures initiating on the surface--primarily at corners. Weibull predictions of fracture strengths for the hole specimens based on the properties of the curved specimens were reasonably effective for the circular holes, but not for the elliptical holes.

Evaluation of the association between fecal excretion of Mycobacterium avium subsp paratuberculosis and detection in colostrum and on teat skin surfaces of dairy cows

USDA-ARS?s Scientific Manuscript database

Objective—To evaluate the association between fecal excretion of Mycobacterium avium subsp paratuberculosis (MAP) by dairy cows in the periparturient period and detection of MAP DNA in colostrum specimens and on teat skin surfaces. Design—Cross-sectional study. Animals—112 Holstein cows. Procedures—...

Spatial variations in a.c. susceptibility and microstructure for the YBa2Cu3O(7-x) superconductor and their correlation with room-temperature ultrasonic measurements

NASA Technical Reports Server (NTRS)

Roth, Don J.; Hepp, Aloysius F.; Deguire, Mark R.; Dolhert, Leonard E.

1991-01-01

The spatial (within-sample) uniformity of superconducting behavior and microstructure in YBa2Cu30(7-x) specimens over the pore fraction range of 0.10 to 0.25 was examined. The viability of using a room-temperature, nondestructive characterization method (ultrasonic velocity imaging) to predict spatial variability was determined. Spatial variations in superconductor properties were observed for specimens containing 0.10 pore fraction. An ultrasonic velocity image constructed from measurements at 1 mm increments across one such specimen revealed microstructural variation between edge and center locations that correlated with variations in alternating-current shielding and loss behavior. Optical quantitative image analysis on sample cross-sections revealed pore fraction to be the varying microstructural feature.

Spatial variations in ac susceptibility and microstructure for the YBa2Cu3O(7-x) superconductor and their correlation with room-temperature ultrasonic measurements

NASA Technical Reports Server (NTRS)

Roth, Don J.; Deguire, Mark R.; Dolhert, Leonard E.; Hepp, Aloysius F.

1991-01-01

The spatial (within-sample) uniformity of superconducting behavior and microstructure in YBa2Cu3O(7-x) specimens over the pore fraction range of 0.10 to 0.25 was examined. The viability of using a room-temperature, nondestructive characterization method (ultrasonic velocity imaging) to predict spatial variability was determined. Spatial variations in superconductor properties were observed for specimens containing 0.10 pore fraction. An ultrasonic velocity image constructed from measurements at 1 mm increments across one such specimen revealed microstructural variation between edge and center locations that correlated with variations in alternating-current shielding and loss behavior. Optical quantitative image analysis on sample cross-sections revealed pore fraction to be the varying microstructural feature.

Is localized infrared spectroscopy now possible in the electron microscope?

PubMed

Rez, Peter

2014-06-01

The recently developed in-column monochromators make it possible to record energy-c spectra with resolutions better than 30 meV from nanometer-sized regions. It should therefore in principle be possible to detect localized vibrational excitations. The scattering geometry in the electron microscope means that bond stretching in the specimen plane or longitudinal optic phonons dominate the scattering. Most promising for initial studies are vibrations with energies between 300 and 400 meV from hydrogen bonded to other atoms. Estimates of the scattering cross-sections on the basis of a simple model show that they are about the same as inner shell scattering cross-sections. Cross-sections also increase with charge transfer between the atoms, and theory incorporating realistic charge distributions shows that signal/noise is the only limitation to high-resolution imaging. Given the magnitude of the scattering cross-sections, minimizing the tail of the zero-loss peak is just as important as achieving a small-width at half-maximum. Improvements in both resolution and controlling the zero-loss tail will be necessary before it is practical to detect optic phonons in solids between 40 and 60 meV.

Study of foldable elastic tubes for large space structure applications, phase 1

NASA Technical Reports Server (NTRS)

Jones, I. W.; Boateng, C.; Williams, C. D.

1980-01-01

Structural members that might be suitable for strain energy deployable structures, are discussed with emphasis on a thin-walled cylindrical tube with a cross-section that is called 'bi-convex'. The design of bi-convex tube test specimens and their fabrication are described as well as the design and construction of a special purpose testing machine to determine the deployment characteristics. The results of the first series of tests were quite mixed, but clearly revealed that since most of the specimens failed to deploy completely, due to a buckling problem, this type of tube requires some modification in order to be viable.

The Effect of Dimensional Changes on Square V-Notched Charpy Bars (Sixth Partial Report on Temper Brittleness)

DTIC Science & Technology

1949-01-13

Charpy specimens. These data are for one steel which has been given a single heat treatment. The effects of a reduction in cross-sectional area and of...air cooled. After this they were tempered at 650oC (1200*?) for 1 hour and water quenched. This treatment produced a structure of tempered bainite

Nano-scale phase transformation in Ti-implanted austenitic 301 stainless steel.

PubMed

Gustiono, Dwi; Sakaguchi, Norihito; Shibayama, Tamaki; Kinoshita, Hiroshi; Takahashi, Heishichiro

2003-01-01

Phase-transformation behaviours were investigated for austenitic 301 stainless steel during implantation at room temperature with 300 keV Ti ions to fluences of 8 x 10(19) to approximately 3 x 10(21) ions m(-2) by means of transmission electron microscopy. The cross-sectional specimen was prepared using a focused ion beam. Plan observation of the implanted specimen showed that phase transformation from gamma-phase to alpha-phase was induced by implantation to a fluence of 3 x 10(20) Ti ions m(-2). The nucleation of the irradiation (implantation)-induced phase increased with the increase of the dose. The orientation relationship between the gamma matrix and the induced alpha martensitic phase was identified as (011)alpha//(111)gamma and [11-1]alpha//[10-1], close to the Kurdjumov-Sachs relationship. Cross-sectional observation after implantation to a fluence of 5 x 10(20) ions m(-2) showed that phase transformation mostly nucleated near the surface and occurred in the higher the concentration gradient of the implanted ion, i.e. a higher stress concentration takes place and this stress introduced by the implanted ions acts as a driving force for the transformation.

Imaging and elemental mapping of biological specimens with a dual-EDS dedicated scanning transmission electron microscope.

PubMed

Wu, J S; Kim, A M; Bleher, R; Myers, B D; Marvin, R G; Inada, H; Nakamura, K; Zhang, X F; Roth, E; Li, S Y; Woodruff, T K; O'Halloran, T V; Dravid, Vinayak P

2013-05-01

A dedicated analytical scanning transmission electron microscope (STEM) with dual energy dispersive spectroscopy (EDS) detectors has been designed for complementary high performance imaging as well as high sensitivity elemental analysis and mapping of biological structures. The performance of this new design, based on a Hitachi HD-2300A model, was evaluated using a variety of biological specimens. With three imaging detectors, both the surface and internal structure of cells can be examined simultaneously. The whole-cell elemental mapping, especially of heavier metal species that have low cross-section for electron energy loss spectroscopy (EELS), can be faithfully obtained. Optimization of STEM imaging conditions is applied to thick sections as well as thin sections of biological cells under low-dose conditions at room and cryogenic temperatures. Such multimodal capabilities applied to soft/biological structures usher a new era for analytical studies in biological systems. Copyright © 2013 Elsevier B.V. All rights reserved.

Features of Cross-Correlation Analysis in a Data-Driven Approach for Structural Damage Assessment

PubMed Central

Camacho Navarro, Jhonatan; Ruiz, Magda; Villamizar, Rodolfo; Mujica, Luis

2018-01-01

This work discusses the advantage of using cross-correlation analysis in a data-driven approach based on principal component analysis (PCA) and piezodiagnostics to obtain successful diagnosis of events in structural health monitoring (SHM). In this sense, the identification of noisy data and outliers, as well as the management of data cleansing stages can be facilitated through the implementation of a preprocessing stage based on cross-correlation functions. Additionally, this work evidences an improvement in damage detection when the cross-correlation is included as part of the whole damage assessment approach. The proposed methodology is validated by processing data measurements from piezoelectric devices (PZT), which are used in a piezodiagnostics approach based on PCA and baseline modeling. Thus, the influence of cross-correlation analysis used in the preprocessing stage is evaluated for damage detection by means of statistical plots and self-organizing maps. Three laboratory specimens were used as test structures in order to demonstrate the validity of the methodology: (i) a carbon steel pipe section with leak and mass damage types, (ii) an aircraft wing specimen, and (iii) a blade of a commercial aircraft turbine, where damages are specified as mass-added. As the main concluding remark, the suitability of cross-correlation features combined with a PCA-based piezodiagnostic approach in order to achieve a more robust damage assessment algorithm is verified for SHM tasks. PMID:29762505

Features of Cross-Correlation Analysis in a Data-Driven Approach for Structural Damage Assessment.

PubMed

Camacho Navarro, Jhonatan; Ruiz, Magda; Villamizar, Rodolfo; Mujica, Luis; Quiroga, Jabid

2018-05-15

This work discusses the advantage of using cross-correlation analysis in a data-driven approach based on principal component analysis (PCA) and piezodiagnostics to obtain successful diagnosis of events in structural health monitoring (SHM). In this sense, the identification of noisy data and outliers, as well as the management of data cleansing stages can be facilitated through the implementation of a preprocessing stage based on cross-correlation functions. Additionally, this work evidences an improvement in damage detection when the cross-correlation is included as part of the whole damage assessment approach. The proposed methodology is validated by processing data measurements from piezoelectric devices (PZT), which are used in a piezodiagnostics approach based on PCA and baseline modeling. Thus, the influence of cross-correlation analysis used in the preprocessing stage is evaluated for damage detection by means of statistical plots and self-organizing maps. Three laboratory specimens were used as test structures in order to demonstrate the validity of the methodology: (i) a carbon steel pipe section with leak and mass damage types, (ii) an aircraft wing specimen, and (iii) a blade of a commercial aircraft turbine, where damages are specified as mass-added. As the main concluding remark, the suitability of cross-correlation features combined with a PCA-based piezodiagnostic approach in order to achieve a more robust damage assessment algorithm is verified for SHM tasks.

Capillary test specimen, system, and methods for in-situ visualization of capillary flow and fillet formation

DOEpatents

Hall, Aaron C.; Hosking, F. Michael ,; Reece, Mark

2003-06-24

A capillary test specimen, method, and system for visualizing and quantifying capillary flow of liquids under realistic conditions, including polymer underfilling, injection molding, soldering, brazing, and casting. The capillary test specimen simulates complex joint geometries and has an open cross-section to permit easy visual access from the side. A high-speed, high-magnification camera system records the location and shape of the moving liquid front in real-time, in-situ as it flows out of a source cavity, through an open capillary channel between two surfaces having a controlled capillary gap, and into an open fillet cavity, where it subsequently forms a fillet on free surfaces that have been configured to simulate realistic joint geometries. Electric resistance heating rapidly heats the test specimen, without using a furnace. Image-processing software analyzes the recorded images and calculates the velocity of the moving liquid front, fillet contact angles, and shape of the fillet's meniscus, among other parameters.

Tomography experiment of an integrated circuit specimen using 3 MeV electrons in the transmission electron microscope.

PubMed

Zhang, Hai-Bo; Zhang, Xiang-Liang; Wang, Yong; Takaoka, Akio

2007-01-01

The possibility of utilizing high-energy electron tomography to characterize the micron-scale three dimensional (3D) structures of integrated circuits has been demonstrated experimentally. First, electron transmission through a tilted SiO(2) film was measured with an ultrahigh-voltage electron microscope (ultra-HVEM) and analyzed from the point of view of elastic scattering of electrons, showing that linear attenuation of the logarithmic electron transmission still holds valid for effective specimen thicknesses up to 5 microm under 2 MV accelerating voltages. Electron tomography of a micron-order thick integrated circuit specimen including the Cu/via interconnect was then tried with 3 MeV electrons in the ultra-HVEM. Serial projection images of the specimen tilted at different angles over the range of +/-90 degrees were acquired, and 3D reconstruction was performed with the images by means of the IMOD software package. Consequently, the 3D structures of the Cu lines, via and void, were revealed by cross sections and surface rendering.

Corrosion behaviour of friction-bit-joined and weld-bonded AA7075-T6/galvannealed DP980

DOE PAGES

Lim, Yong Chae; Squires, Lile; Pan, Tsung-Yu; ...

2016-12-22

Joining of aluminium alloys 7075-T6 and galvannealed dual phase 980 steel was achieved by friction bit joining (FBJ) and weld-bonding (FBJ + adhesive) processes. Accelerated laboratory-scale corrosion tests were performed on both FBJ only and weld-bonded specimens to study joint strength under a corrosive environment. Static lap shear tests showed that both FBJ only and weld-bonded cases generally retained more than 80% of the joint strength of non-corroded specimens at the end of corrosion testing. The presence of Zn/Fe coating on the steel substrate resulted in improved corrosion resistance for FBJ specimens, compared to joints produced with bare steel. Finally,more » an optical microscopy was used for cross-sectional analysis of corroded specimens. Some corrosion on the joining bit was observed near the bit head. However, the joining bit was still intact on the steel substrate, indicating that the primary bond was sound.« less

Corrosion behaviour of friction-bit-joined and weld-bonded AA7075-T6/galvannealed DP980

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

Lim, Yong Chae; Squires, Lile; Pan, Tsung-Yu

Joining of aluminium alloys 7075-T6 and galvannealed dual phase 980 steel was achieved by friction bit joining (FBJ) and weld-bonding (FBJ + adhesive) processes. Accelerated laboratory-scale corrosion tests were performed on both FBJ only and weld-bonded specimens to study joint strength under a corrosive environment. Static lap shear tests showed that both FBJ only and weld-bonded cases generally retained more than 80% of the joint strength of non-corroded specimens at the end of corrosion testing. The presence of Zn/Fe coating on the steel substrate resulted in improved corrosion resistance for FBJ specimens, compared to joints produced with bare steel. Finally,more » an optical microscopy was used for cross-sectional analysis of corroded specimens. Some corrosion on the joining bit was observed near the bit head. However, the joining bit was still intact on the steel substrate, indicating that the primary bond was sound.« less

A Snapshot Avian Surveillance Reveals West Nile Virus and Evidence of Wild Birds Participating in Toscana Virus Circulation.

PubMed

Hacioglu, Sabri; Dincer, Ender; Isler, Cafer Tayer; Karapinar, Zeynep; Ataseven, Veysel Soydal; Ozkul, Aykut; Ergunay, Koray

2017-10-01

Birds are involved in the epidemiology of several vector-borne viruses, as amplification hosts for viruses, dissemination vehicles for the vectors, and sources of emerging strains in cross-species transmission. Turkey provides diverse habitats for a variety of wild birds and is located along major bird migration routes. This study was undertaken to provide a cross-sectional screening of avian specimens for a spectrum of vector-borne viruses. The specimens were collected in Hatay province, in the Mediterranean coast of the Anatolian peninsula, located in the convergence zone of the known migration routes. Generic PCR assays were used for the detection of members of Nairovirus, Flavivirus, and Phlebovirus genera of Flaviviridae and Bunyaviridae families. The circulating viruses were characterized via sequencing and selected specimens were inoculated onto Vero cell lines for virus isolation. Specimens from 72 wild birds belonging in 8 orders and 14 species were collected. A total of 158 specimens that comprise 32 sera (20.3%) from 7 species and 126 tissues (79.7%) from 14 species were screened. Eight specimens (8/158, 5%), obtained from 4 individuals (4/72, 5.5%), were positive. West Nile virus (WNV) lineage 1 sequences were characterized in the spleen, heart, and kidney tissues from a lesser spotted eagle (Clanga pomarina), which distinctly clustered from sequences previously identified in Turkey. Toscana virus (TOSV) genotype A and B sequences were identified in brain and kidney tissues from a greater flamingo (Phoenicopterus roseus), a great white pelican (Pelecanus onocrotalus), and a black stork (Ciconia nigra), without successful virus isolation. Partial amino acid sequences of the viral nucleocapsid protein revealed previously unreported substitutions. This study documents the involvement of avians in WNV dispersion in Anatolia as well in TOSV life cycle.

Laser-scanned fluorescence of nonlased/normal, lased/normal, nonlased/carious, and lased/carious enamel

NASA Astrophysics Data System (ADS)

Zakariasen, Kenneth L.; Barron, Joseph R.; Paton, Barry E.

1992-06-01

Research has shown that low levels of CO2 laser irradiation raise enamel resistance to sub-surface demineralization. Additionally, laser scanned fluorescence analysis of enamel, as well a laser and white light reflection studies, have potential for both clinical diagnosis and comparative research investigations of the caries process. This study was designed to compare laser fluorescence and laser/white light reflection of (1) non-lased/normal with lased/normal enamel and (2) non-lased/normal with non-lased/carious and lased/carious enamel. Specimens were buccal surfaces of extracted third molars, coated with acid resistant varnish except for either two or three 2.25 mm2 windows (two window specimens: non-lased/normal, lased/normal--three window specimens: non-lased/normal, non-lased carious, lased/carious). Teeth exhibiting carious windows were immersed in a demineralizing solution for twelve days. Non-carious windows were covered with wax during immersion. Following immersion, the wax was removed, and fluorescence and laser/white light reflection analyses were performed on all windows utilizing a custom scanning laser fluorescence spectrometer which focuses light from a 25 mWatt He-Cd laser at 442 nm through an objective lens onto a cross-section >= 3 (mu) in diameter. For laser/white light reflection analyses, reflected light intensities were measured. A HeNe laser was used for laser light reflection studies. Following analyses, the teeth are sectioned bucco-lingually into 80 micrometers sections, examined under polarized light microscopy, and the lesions photographed. This permits comparison between fluorescence/reflected light values and the visualized decalcification areas for each section, and thus comparisons between various enamel treatments and normal enamel. The enamel specimens are currently being analyzed.

Shear bond strength of composite to deep dentin after treatment with two different collagen cross-linking agents at varying time intervals.

PubMed

Srinivasulu, S; Vidhya, S; Sujatha, M; Mahalaxmi, S

2012-01-01

This in vitro study evaluated the shear bond strength of composite resin to deep dentin using a total etch adhesive after treatment with two collagen cross-linking agents at varying time intervals. Thirty freshly extracted human maxillary central incisors were sectioned longitudinally into equal mesial and distal halves (n=60). The proximal deep dentin was exposed, maintaining a remaining dentin thickness (RDT) of approximately 1 mm. The specimens were randomly divided into three groups based on the surface treatment of dentin prior to bonding as follows: group I (n=12, control): no prior dentin surface treatment; group II (n=24): dentin surface pretreated with 10% sodium ascorbate; and group III (n=24): dentin surface pretreated with 6.5% proanthocyanidin. Groups II and III were further subdivided into two subgroups of 12 specimens each, based on the pretreatment time of five minutes (subgroup A) and 10 minutes (subgroup B). Shear bond strength of the specimens was tested with a universal testing machine, and the data were statistically analyzed. Significantly higher shear bond strength to deep dentin was observed in teeth treated with 10% sodium ascorbate (group II) and 6.5% proanthocyanidin (group III) compared to the control group (group I). Among the collagen cross-linkers used, specimens treated with proanthocyanidin showed significantly higher shear bond strength values than those treated with sodium ascorbate. No significant difference was observed between the five-minute and 10-minute pretreatment times in groups II and III. It can be concluded that dentin surface pretreatment with both 10% sodium ascorbate and 6.5% proanthocyanidin resulted in significant improvement in bond strength of resin composite to deep dentin.

Sectioning studies of biomimetic collagen-hydroxyapatite coatings on Ti-6Al-4V substrates using focused ion beam

NASA Astrophysics Data System (ADS)

Hu, Changmin; Yu, Le; Wei, Mei

2018-06-01

A biomimetic bone-like collagen-hydroxyapatite (Col-HA) composite coating was formed on a surface-treated Ti-6Al-4V alloy substrate via simultaneous collagen self-assembly and hydroxyapatite nucleation. The coating process has been carried out by immersing sand-blasted, acid-etched and UV irradiated Ti-6Al-4V alloy in type I collagen-containing modified simulated body fluid (m-SBF). The surface morphology and phase composition of the coating were characterized using various techniques. More importantly, dual-beam FIB/SEMs with either gallium ion source (GFIB) or xenon plasma ion source (PFIB) were used to investigate the cross-sectional features of the biomimetic Col-HA composite coating in great details. As a result, the cross-sectional images and thin transmission electron microscopy (TEM) specimens were successfully obtained from the composite coating with no obvious damages or milling ion implantations. Both the cross-sectional SEM and TEM results have confirmed that the Col-HA coating demonstrates a similar microstructure to that of pure HA coating with homogeneously distributed elements across the whole cross section. Both coatings consist of a uniform, crack-free gradient structure with a dense layer adjacent to the interface between the Ti-6Al-4V substrate and the coating facilitating a strong bonding, while a porous structure at the coating surface aiding cell attachment.

Dual Priming Oligonucleotides for Broad-Range Amplification of the Bacterial 16S rRNA Gene Directly from Human Clinical Specimens

PubMed Central

Simmon, Keith; Karaca, Dilek; Langeland, Nina; Wiker, Harald G.

2012-01-01

Broad-range amplification and sequencing of the bacterial 16S rRNA gene directly from clinical specimens are offered as a diagnostic service in many laboratories. One major pitfall is primer cross-reactivity with human DNA which will result in mixed chromatograms. Mixed chromatograms will complicate subsequent sequence analysis and impede identification. In SYBR green real-time PCR assays, it can also affect crossing threshold values and consequently the status of a specimen as positive or negative. We evaluated two conventional primer pairs in common use and a new primer pair based on the dual priming oligonucleotide (DPO) principle. Cross-reactivity was observed when both conventional primer pairs were used, resulting in interpretation difficulties. No cross-reactivity was observed using the DPOs even in specimens with a high ratio of human to bacterial DNA. In addition to reducing cross-reactivity, the DPO principle also offers a high degree of flexibility in the design of primers and should be considered for any PCR assay intended for detection and identification of pathogens directly from human clinical specimens. PMID:22278843

Directional acceleration vector-driven displacement of fluids (DAVD-DOF)

NASA Technical Reports Server (NTRS)

Clarke, Mark S. F. (Inventor); Feeback, Daniel L. (Inventor)

2004-01-01

Centrifugal analyzer and method for staining biological or non-biological samples in microgravity, wherein the method utilizes an increase in weight of a fluid sample as a function of g-load, to overcome cohesive and frictional forces from preventing its movement in a preselected direction. Apparatus is characterized by plural specimen reservoirs and channels in a slide, each channel being of differing cross-section, wherein respective samples are selectively dispensed, from the reservoirs in response to an imposed g-factor, precedent to sample staining. Within the method, one thus employs microscope slides which define channels, each being of a differing cross-section dimension relative to others. In combination therewith, centrifugal slide mounting apparatus controllably imposes g-vectors of differing magnitudes within a defined structure of the centrifuge such as a chip array.

[Which changes occur in nerve grafts harvested with a nerve stripper? Morphological studies].

PubMed

Koller, R; Frey, M; Rab, M; Deutinger, M; Freilinger, G

1995-03-01

A histological and morphometric study was undertaken in order to evaluate the alterations in sural nerves harvested for nerve grafting using a nerve stripper. In 19 nerves biopsies were taken from the proximal and/or the distal end of the stripped nerve graft. Cross sections were examined for alterations of the perineurium and the myelin sheaths. In four nerves alterations within the perineurium were found, which affected 37% of the endoneural cross-sectional area on the average. In all specimens, the perineurial sheath was seen to be intact. The results of the present study suggest that harvesting of a nerve graft using a stripper does not cause major injuries to the graft and therefore successful neurotization of the graft should not be impaired.

An examination of impact damage in glass-phenolic and aluminum honeycomb core composite panels

NASA Technical Reports Server (NTRS)

Nettles, A. T.; Lance, D. G.; Hodge, A. J.

1990-01-01

An examination of low velocity impact damage to glass-phenolic and aluminum core honeycomb sandwich panels with carbon-epoxy facesheets is presented. An instrumented drop weight impact test apparatus was utilized to inflict damage at energy ranges between 0.7 and 4.2 joules. Specimens were checked for extent of damage by cross sectional examination. The effect of core damage was assessed by subjecting impact-damaged beams to four-point bend tests. Skin-only specimens (facings not bonded to honeycomb) were also tested for comparison purposes. Results show that core buckling is the first damage mode, followed by delaminations in the facings, matrix cracking, and finally fiber breakage. The aluminum honeycomb panels exhibited a larger core damage zone and more facing delaminations than the glass-phenolic core, but could withstand more shear stress when damaged than the glass-phenolic core specimens.

Tensile properties of V-5Cr-5Ti alloy after exposure in air environment

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

Natesan, K.; Soppet, W.K.

1997-04-01

Oxidation studies were conducted on V-5Cr-5Ti alloy specimens in an air environment to evaluate the oxygen uptake behavior of the alloy as a function of temperature and exposure time. The oxidation rates, calculated from parabolic kinetic measurements of thermogravimetric testing and confirmed by microscopic analysis of cross sections of exposed specimens, were 5, 17, and 27 {mu}m per year after exposure at 300, 400, and 500{degrees}C, respectively. Uniaxial tensile tests were conducted at room temperature and at 500{degrees}C on preoxidized specimens of the alloy to examine the effects of oxidation and oxygen migration on tensile strength and ductility. Correlations weremore » developed between tensile strength and ductility of the oxidized alloy and microstructural characteristics such as oxide thickness, depth of hardened layer, depth of intergranular fracture zone, and transverse crack length.« less

Vortex Structures in the Shock-deformed Armor Steels

NASA Astrophysics Data System (ADS)

Atroshenko, Svetlana; Meshcheryakov, Yuri; Natalia, Naumova

2009-06-01

Several kinds of armor steel were tested under uniaxial strain conditions within impact velocity range from 250 to 400 m/s. Using optical and REM microscopy, the post shocked specimens were studied to reveal the kinematical mechanisms of dynamic deformation at the mesoscale. In all the specimens, the cross-section of specimens was found to be filled with rotational cells of very complex space morphology. Each rotation cell consists of central core of 1-2 μm in diameter and family of petals surrounding the core, so the space configuration of eddy is closely remands a fan of total size 6-7 μm. During the deformation, the petals move around the core providing the vortical motion of rotation as a whole. Dependence of rotational cell density on the strain rate changes non-monotonously, maximum density corresponds to maximum macrohardness and maximum of spall-strength of steel.

Variations in the course and microanatomical study of the lateral femoral cutaneous nerve and its clinical importance.

PubMed

Ray, Biswabina; D'Souza, A S; Kumar, Brijesh; Marx, Chakravarthy; Ghosh, Buddhadeb; Gupta, Nanda Kishore; Marx, Anitha

2010-11-01

The lateral femoral cutaneous nerve (LFCN), a branch from the lumbar plexus, may come to the clinician's or surgeon's attention. We studied this nerve to determine its location and its relationship with neighboring structures around the anterior superior iliac spine (ASIS) and the inguinal ligament (IL). Additionally, cross-sectional microanatomy of the LFCN at the IL was studied. The LFCN was dissected in 47 lower limbs from formalin-fixed cadavers. The distances from the ASIS to the point where the LFCN crossed the IL and the lateral border of the sartorius were measured. The distance between the ASIS and the point it pierced the deep fascia was also measured. Twelve nerve specimens at the IL were collected for histological sectioning and were stained with hematoxylin and eosin. On examination of the cross-sectional area, the nonfascicular area was wider than the fascicular area because of an increased amount of thick collagen fibers. This study may be of help to clinicians managing meralgia paresthetica and may also assist in defining a safe area for surgical intervention on the anterolateral aspect of the thigh.

Is there a correlation between right bronchus length and diameter with age?

PubMed

Otoch, José Pinhata; Minamoto, Hélio; Perini, Marcos; Carneiro, Fred Olavo; de Almeida Artifon, Everson Luiz

2013-06-01

Right main bronchial anatomy knowledge is essential to guide endoscopic stent placement in modern era. The aim is to describe right bronchial anatomy, cross-area and its relation with the right pulmonary artery and patient's age. One hundred thirty four cadaveric specimens were studied after approval by the Research and Ethics Committee at the University of São Paulo Medical School and Medical Forensic Institute of São Paulo. All necropsies were performed in natura after 24 hours of death and patients with previous pulmonary disease were excluded. Landmarks to start measurement were the first tracheal ring, vertex of carina, first right bronchial ring, and right pulmonary artery area over the right main bronchus. After mobilization, the specimens were measured using a caliper and measurement of distances was recorded in centimeters at landmarks points. All the measures (distances, cross sectional area and planes) were performed by three independent observers and recorded as mean, standard error and ranges. Student t test was used to compare means and linear regression was applied to correlate the measurements. From 134 specimens studied, 34 were excluded (10 with previous history of pulmonary diseases, surgery or deformities and 24 of female gender). Linear regression showed proportionality between tracheal length and right bronchus length; with the area at first tracheal ring and carina and also between the cross sectional area at these points. Linear regression analysis between tracheal length and age (R=0.593 P<0.005), right bronchus length and age (R=0.523, P<0.005), area of contact between right bronchus and right pulmonary artery and age (R=0.35, P<0.005). We can conclude that large airways grow progressively with increasing age in male gender. There was a direct correlation between age and tracheal length; as has age and right bronchus length. There was a direct correlation between age and the area of the right bronchus covered by the right pulmonary artery.

Follistatin: A Potential Anabolic Treatment for Re-Innervated Muscle

DTIC Science & Technology

2016-09-01

and force generation studies of tibial nerve and gastrocnemius muscle.- pending • Immunohistology staining and histology of muscle (3 months) Fiber...Cross sections of muscle specimens will be stained and fiber size, axon numbers, and myelination measured.- pending • Data Analysis (3 months...AV-288 Follistatin 5 Control 5 Follistatin Protein 2 Animal Weight ( grams ): AV FS-288 (FPP6 to FPP10) Average 256.72 STDEV 6.28267459

Field-emission scanning electron microscopy and energy-dispersive x-ray analysis to understand the role of tannin-based dyes in the degradation of historical wool textiles.

PubMed

Restivo, Annalaura; Degano, Ilaria; Ribechini, Erika; Pérez-Arantegui, Josefina; Colombini, Maria Perla

2014-10-01

An innovative approach, combining field-emission scanning electron microscopy (FESEM) with energy dispersive X-ray spectroscopy (EDX) analysis, is presented to investigate the degradation mechanisms affecting tannin-dyed wool. In fact, tannin-dyed textiles are more sensitive to degradation then those dyed with other dyestuffs, even in the same conservation conditions. FESEM-EDX was first used to study a set of 48 wool specimens (artificially aged) dyed with several raw materials and mordants, and prepared according to historical dyeing recipes. EDX analysis was performed on the surface of wool threads and on their cross-sections. In addition, in order to validate the model formulated by the analysis of reference materials, several samples collected from historical and archaeological textiles were subjected to FESEM-EDX analysis. FESEM-EDX investigations enabled us to reveal the correlation between elemental composition and morphological changes. In addition, aging processes were clarified by studying changes in the elemental composition of wool from the protective cuticle to the fiber core in cross-sections. Morphological and elemental analysis of wool specimens and of archaeological and historical textiles showed that the presence of tannins increases wool damage, primarily by causing a sulfur decrease and fiber oxidation.

Chemical Imaging Analysis of Environmental Particles Using the Focused Ion Beam/Scanning Electron Microscopy Technique. Microanalysis Insights into Atmospheric Chemistry of Fly Ash

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

Chen, Haihan; Grassian, Vicki H.; Saraf, Laxmikant V.

2012-11-08

Airborne fly ash from coal combustion may represent a source of bioavailable iron (Fe) in the open ocean. However, few studies have been made focusing on Fe speciation and distribution in coal fly ash. In this study, chemical imaging of fly ash has been performed using a dual-beam FIB/SEM (focused ion beam/scanning electron microscope) system for a better understanding of how simulated atmospheric processing modify the morphology, chemical compositions and element distributions of individual particles. A novel approach has been applied for cross-sectioning of fly ash specimen with a FIB in order to explore element distribution within the interior ofmore » individual particles. Our results indicate that simulated atmospheric processing causes disintegration of aluminosilicate glass, a dominant material in fly ash particles. Aluminosilicate-phase Fe in the inner core of fly ash particles is more easily mobilized compared with oxide-phase Fe present as surface aggregates on fly ash spheres. Fe release behavior depends strongly on Fe speciation in aerosol particles. The approach for preparation of cross-sectioned specimen described here opens new opportunities for particle microanalysis, particular with respect to inorganic refractive materials like fly ash and mineral dust.« less

Extraocular Muscles in Patients With Infantile Nystagmus

PubMed Central

Berg, Kathleen T.; Hunter, David G.; Bothun, Erick D.; Antunes-Foschini, Rosalia; McLoon, Linda K.

2013-01-01

Objective To test the hypothesis that the extraocular muscles (EOMs) of patients with infantile nystagmus have muscular and innervational adaptations that may have a role in the involuntary oscillations of the eyes. Methods Specimens of EOMs from 10 patients with infantile nystagmus and postmortem specimens from 10 control subjects were prepared for histologic examination. The following variables were quantified: mean myofiber cross-sectional area, myofiber central nucleation, myelinated nerve density, nerve fiber density, and neuromuscular junction density. Results In contrast to control EOMs, infantile nystagmus EOMs had significantly more centrally nucleated myofibers, consistent with cycles of degeneration and regeneration. The EOMs of patients with nystagmus also had a greater degree of heterogeneity in myofiber size than did those of controls, with no difference in mean myofiber cross-sectional area. Mean myelinated nerve density, nerve fiber density, and neuromuscular junction density were also significantly decreased in infantile nystagmus EOMs. Conclusions The EOMs of patients with infantile nystagmus displayed a distinct hypoinnervated phenotype. This represents the first quantification of changes in central nucleation and myofiber size heterogeneity, as well as decreased myelinated nerve, nerve fiber, and neuromuscular junction density. These results suggest that deficits in motor innervation are a potential basis for the primary loss of motor control. Clinical Relevance Improved understanding of the etiology of nystagmus may direct future diagnostic and treatment strategies. PMID:22411664

Acoustic emission monitoring of low velocity impact damage in graphite/epoxy laminates during tensile loading

NASA Technical Reports Server (NTRS)

Parker, Bradford H.

1992-01-01

An acoustic emission (AE) system was set up in a linear location data acquisition mode to monitor the tensile loading of eight-ply quasi-isotropic graphite/epoxy specimens containing low velocity impact damage. The impact damage was induced using an instrumented drop weight tower. During impact, specimens were supported by either an aluminum plate or a membrane configuration. Cross-sectional examinations revealed that the aluminum plate configuration resulted in primarily matrix cracking and back surface fiber failure. The membrane support resulted in only matrix cracking and delamination damage. Penetrant enhanced radiography and immersion ultrasonics were used in order to assess the amount of impact damage in each tensile specimen. During tensile loading, AE reliably detected and located the damage sites which included fiber failure. All specimens with areas of fiber breakage ultimately failed at the impact site. AE did not reliably locate damage which consisted of only delaminations and matrix cracking. Specimens with this type of damage did not ultimately fail at the impact site. In summary, AE demonstrated the ability to increase the reliability of structural proof tests; however, the successful use of this technique requires extensive baseline testing.

Performance of self-collected cervical samples in screening for future precancer using human papillomavirus DNA testing.

PubMed

Porras, Carolina; Hildesheim, Allan; González, Paula; Schiffman, Mark; Rodríguez, Ana Cecilia; Wacholder, Sholom; Jiménez, Silvia; Quint, Wim; Guillen, Diego; Kreimer, Aimée R; Herrero, Rolando

2015-01-01

Self-collected human papillomavirus (HPV) testing could reduce barriers to cervical cancer screening, with performance comparable to clinician-collected specimens. The ability of self-collected specimens to cross-sectionally and prospectively detect precursor lesions was investigated in an HPV vaccine randomized trial in Costa Rica. In the trial, 7466 women age 18 to 25 years received an HPV16/18 or control vaccine and were followed at least annually for four years. In this secondary analysis, we included all women who provided a self-collected cervicovaginal specimen six months after enrollment (5109 women = full analytical cohort). A subset (615 women = restricted cohort) also had clinician-collected specimens at the six-month postenrollment visit. High-grade squamous intraepithelial lesion or repeat low-grade squamous intraepithelial lesion prompted colposcopic referral throughout the study. HPV testing was performed with SPF10PCR/DEIA/LiPA25. Cross-sectional and prospective sensitivity, specificity, and predictive values were estimated. In the full cohort, one-time HPV testing on self-collected samples detected prevalent CIN2+ with a sensitivity of 88.7% (95% confidence interval [CI] =77.0% to 95.7%) and a specificity of 68.9% (95% CI = 67.6% to 70.1%). For predicting incident CIN2+ in the subsequent four years, sensitivity was 73.9% (95% CI = 65.8% to 81.0%) and specificity 69.4% (95% CI = 68.1% to 70.7%). In the restricted cohort, for incident CIN2+, self-collected HPV was much more sensitive than cytology (80.0% vs 10.0%); relative sensitivity was 0.1 (95% CI = 0.03% to 0.5%). Furthermore, three times more women with normal baseline cytology developed incident CIN2+ than those with negative self-collected HPV. Self-collected and clinician-collected HPV testing had comparable performance. Agreement between self- and clinician-collected samples was 89.7% (kappa = 0.78, McNemar χ2 = 0.62) for carcinogenic HPV types. Self-collected specimens can be used for HPV-based screening, providing sensitivity and specificity comparable with clinician-collected specimens and detecting disease earlier than cytology. © The Author 2014. Published by Oxford University Press. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

Monitoring corrosion of rebar embedded in mortar using guided ultrasonic waves

NASA Astrophysics Data System (ADS)

Ervin, Benjamin Lee

This thesis investigates the use of guided mechanical waves for monitoring uniform and localized corrosion in steel reinforcing bars embedded in concrete. The main forms of structural deterioration from uniform corrosion in reinforced concrete are the destruction of the bond between steel and concrete, the loss of steel cross-sectional area, and the loss of concrete cross-sectional area from cracking and spalling. Localized corrosion, or pitting, leads to severe loss of steel cross-sectional area, creating a high risk of bar tensile failure and unintended transfer of loads to the surrounding concrete. Reinforcing bars were used to guide the waves, rather than bulk concrete, allowing for longer inspection distances due to lower material absorption, scattering, and divergence. Guided mechanical waves in low frequency ranges (50-200 kHz) and higher frequency ranges (2-8 MHz) were monitored in reinforced mortar specimens undergoing accelerated uniform corrosion. The frequency ranges chosen contain wave modes with varying amounts of interaction, i.e. displacement profile, at the material interface. Lower frequency modes were shown to be sensitive to the accumulation of corrosion product and the level of bond between the surrounding mortar and rebar. This allows for the onset of corrosion and bond deterioration to be monitored. Higher frequency modes were shown to be sensitive to changes in the bar profile surface, allowing for the loss of cross-sectional area to be monitored. Guided mechanical waves in the higher frequency range were also used to monitor reinforced mortar specimens undergoing accelerated localized corrosion. The high frequency modes were sensitive to the localized attack. Also promising was the unique frequency spectrum response for both uniform and localized corrosion, allowing the two corrosion types to be differentiated from through-transmission evaluation. The isolated effects of the reinforcing ribs, simulated debonding, simulated pitting, water surrounding, and mortar surrounding were also investigated using guided mechanical waves. Results are presented and discussed within the framework of a corrosion process degradation model and service life. A thorough review and discussion of the corrosion process, modeling the propagation of corrosion, nondestructive methods for monitoring corrosion in reinforced concrete, and guided mechanical waves have also been presented.

A comparative evaluation of in-plane shear test methods for laminated graphite-epoxy composites

NASA Technical Reports Server (NTRS)

Morton, John; Ho, Henjen

1992-01-01

The objectives were to evaluate popular shear test methods for various forms of graphite-epoxy composite materials and to determine the shear response of graphite-epoxy composites with various forms of fiber architecture. Numerical and full-field experimental stress analyses were performed on four shear test configurations for unidirectional and bidirectional graphite-epoxy laminates to assess the uniformity and purity of the shear stress (strain) fields produced in the specimen test section and to determine the material in-plane shear modulus and shear response. The test methods were the 10 deg off-axis, the +/- 45 deg tension, the Iosipescu V-notch, and a compact U-notch specimen. Specimens were prepared from AS4/3501-6 graphite-epoxy panels, instrumented with conventional strain gage rosettes and with a cross-line moire grating, and loaded in a convenient testing machine. The shear responses obtained for each test method and the two methods of specimen instrumentation were compared. In a second phase of the program the shear responses obtained from Iosipescu V-notch beam specimens were determined for woven fabric geometries of different weave and fiber architectures. Again the responses of specimens obtained from strain gage rosettes and moire interferometry were compared. Additional experiments were performed on a bidirectional cruciform specimen which was also instrumented with strain gages and a moire grating.

Damage analysis of CF/AF hybrid fabric reinforced plastic laminated composites with scanned image microscopy

NASA Astrophysics Data System (ADS)

Miyasaka, Chiaki; Kasano, Hideaki; Shull, Peter J.

2004-07-01

The article presents an experimental study that has been conducted to evaluate the impact loading damage within hybrid fabric laminates-carbon and Aramid fibers. The experiments have been undertaken on a series of interply hybrid specimens with different preprags stacking sequences. Impact damage was created using an air-gun like impact device propelling spherical steel balls with diameters of 5.0mm and 10.0mm and having velocities of 113m/s and 40m/s respectively. The resulting specimen surface and internal damage (e.g., micro-cracking and debonding) was visualized nondestructively by a scanning acoustic microscope (SAM) while further interrogation of specific internal damage was visualized using a scanning electron microscope (SEM) on cross-sectioned panels.

Fractographic Observations on the Mechanism of Fatigue Crack Growth in Aluminium Alloys

NASA Astrophysics Data System (ADS)

Alderliesten, R. C.; Schijve, J.; Krkoska, M.

Special load histories are adopted to obtain information about the behavior of the moving crack tip during the increasing and decreasing part of a load cycle. It is associated with the crack opening and closure of the crack tip. Secondly, modern SEM techniques are applied for observations on the morphology of the fractures surfaces of a fatigue crack. Information about the cross section profiles of striations are obtained. Corresponding locations of the upper and the lower fracture surface are also explored in view of the crack extension mechanism. Most experiments are carried out on sheet specimens of aluminum alloys 2024-T3, but 7050-T7451 specimens are also tested in view of a different ductility of the two alloys.

The effects of crushing speed on the energy-absorption capability of composite material

NASA Technical Reports Server (NTRS)

Farley, Gary L.

1987-01-01

The energy-absorption capability as a function of crushing speed was determined for Thornel 300/Fiberite 934 (Gr/E) and Kevlar-49/Fiberite 934 (K/E) composite material. Circular cross section tube specimens were crushed at quasi-static, 6 m/sec, and 12 m/sec speeds. Ply orientations of the tube specimens were (0/+ or - theta) sub 2 and (+ or - theta) sub 3 where theta=15, 45, and 75 degress. Based on the results of these tests the energy-absortion capability of Gr/E and K/E was determined to be a function of crushing speed. The crushing modes based on exterior appearance of the crushed tubes were unchanged for either material. However, the interlaminar crushing behavior changed with crushing speed.

Publications - GMC 382 | Alaska Division of Geological & Geophysical

Science.gov Websites

DGGS GMC 382 Publication Details Title: 1974 NWE Orange Hill, Alaska specimen index: Cross reference of Reference Northwest Explorations, 2010, 1974 NWE Orange Hill, Alaska specimen index: Cross reference of

Non-traditional shape GFRP rebars for concrete reinforcement

NASA Astrophysics Data System (ADS)

Claure, Guillermo G.

The use of glass-fiber-reinforced-polymer (GFRP) composites as internal reinforcement (rebars) for concrete structures has proven to be an alternative to traditional steel reinforcement due to significant advantages such as magnetic transparency and, most importantly, corrosion resistance equating to durability and structural life extension. In recent years, the number of projects specifying GFRP reinforcement has increased dramatically leading the construction industry towards more sustainable practices. Typically, GFRP rebars are similar to their steel counterparts having external deformations or surface enhancements designed to develop bond to concrete, as well as having solid circular cross-sections; but lately, the worldwide composites industry has taken advantage of the pultrusion process developing GFRP rebars with non-traditional cross-sectional shapes destined to optimize their mechanical, physical, and environmental attributes. Recently, circular GFRP rebars with a hollow-core have also become available. They offer advantages such as a larger surface area for improved bond, and the use of the effective cross-sectional area that is engaged to carry load since fibers at the center of a solid cross-section are generally not fully engaged. For a complete understanding of GFRP rebar physical properties, a study on material characterization regarding a quantitative cross-sectional area analysis of different GFRP rebars was undertaken with a sample population of 190 GFRP specimens with rebar denomination ranging from #2 to #6 and with different cross-sectional shapes and surface deformations manufactured by five pultruders from around the world. The water displacement method was applied as a feasible and reliable way to conduct the investigation. In addition to developing a repeatable protocol for measuring cross-sectional area, the objectives of establishing critical statistical information related to the test methodology and recommending improvements to existing provisions and standards allowing for a consistent universal norm for all GFRP rebars were reached. This dissertation also presents an evaluation of the structural behavior of reinforced concrete (RC) beams and slabs using the new type of GFRP rebar consisting of a non-traditional hollow-core shape compared to "traditional" solid round rebars with equivalent cross-sectional areas within the framework of two studies, respectively. To validate the design assumptions following ACI 440.1R design guidelines, two conditions were investigated: under-reinforced (failure controlled by rupture of GFRP rebar); and, over-reinforced (failure controlled by crushing of concrete). For comparison, a cyclic three-point bending load test matrix was developed: for beams, 3 under-reinforced and 3 over-reinforced with hollow-core and solid GFRP rebars, respectively, making a total of 12 RC specimens; for slabs, 3 under-reinforced and 3 over-reinforced with hollow-core and 2 types of solid GFRP rebars, respectively, making a total of 18 RC slabs. The studies on GFRP RC beams and slabs concluded that the hollow-core GFRP rebars were as effective as their solid counterpart and ACI 440.1R design guidelines were applicable to predict their performance. It was shown that final design may be controlled by the permissible deflections as governing parameter for elements under service conditions. Also, a final study with a test matrix containing six extra specimens was generated for post-fire residual strength evaluation of fire-exposed GFRP RC slabs along with temperature gradient in the slabs and dynamic mechanical analysis (DMA) investigation on GFRP samples extracted from the fire-exposed slabs. In this study, the ability of GFRP RC slabs to retain structural integrity during a standards fire exposure as well as determining the residual structural capacity were investigated. The residual strength evaluation of the fire-exposed slabs showed a range of results varying between +/- 10%, of the virgin slabs. And, 19 mm (0.75 in.) cover with normal weight concrete was shown to be adequate to provide the necessary fire protection to the GFRP rebars preventing irreversible damage for two-hour fire rated GFRP RC slabs subjected to service loads; also, from the DMA and glass transition temperature of samples extracted from the GFRP rebars, it is inferred that the resin had undergone a post curing phase.

Phenotypic and antibiogram pattern of V. cholerae isolates from a tertiary care hospital in Mumbai during 2004–2013: a retrospective cross-sectional study

PubMed Central

Torane, V; Kuyare, S; Nataraj, G; Mehta, P; Dutta, S; Sarkar, B

2016-01-01

Objectives Cholera is a major gastroenteric disease with reports on fluctuation and resistance. Hence, the objective is to determine the trend in seasonality, resistance pattern, prevalent biotypes, serotypes and phage types between 2004 and 2013 among Vibrio cholerae isolates. Design A retrospective cross-sectional study. Settings A single-centre study was carried out at a tertiary care hospital in a metropolitan city (Mumbai) of a developing country (India). Methods Records of stool specimen cultures of patients with suspected cholera from January 2004 to December 2013 were analysed. The organisms were identified as per standard protocol. Antimicrobial susceptibility testing was performed as per Clinical Laboratory Standard Institute. Biotyping, serotyping and phage typing were carried out. From the confirmed cases of cholera, demographic and laboratory details were noted. Descriptive analysis was used and the data were presented in the form of percentages. Results Vibrio cholerae was predominant in males and was isolated from 9.41% (439/4664) of stool specimens. Variability was found in terms of the gross appearance of stool specimens, seasonal trend and antibiotic resistance pattern. The antimicrobial susceptibility showed a waxing and waning pattern for most of the antibiotics (ampicillin, cefuroxime, chloramphenicol, tetracycline) tested, while for a few others the strains were either uniformly sensitive (gentamicin, norfloxacin) or resistant (trimethoprim-sulfamethoxazole, nalidixic acid). All isolates belonged to subgroup O1 and biotype El Tor. The most common serotype was Ogawa. The predominant phage type was T2 (old scheme) and T27 (new scheme). Conclusions The predominant biotype, serotype and phage type were El Tor, Ogawa and T27 phage, respectively. The changing trends in antimicrobial resistance pattern over the years necessitate continued epidemiological and microbiological surveillance of the disease. PMID:27888174

Effect of ceramic infrastructure on the failure behavior and stress distribution of fixed partial dentures.

PubMed

Borba, Márcia; Duan, Yuanyuan; Griggs, Jason A; Cesar, Paulo F; Della Bona, Álvaro

2015-04-01

The effect of the ceramic infrastructure (IS) on the failure behavior and stress distribution of fixed partial dentures (FPDs) was evaluated. Twenty FPDs with a connector cross-section of 16 mm(2) were produced for each IS and veneered with porcelain: (YZ) Vita In-Ceram YZ/Vita VM9 porcelain; (IZ) Vita In-Ceram Zirconia/Vita VM7 porcelain; (AL) Vita In-Ceram AL/Vita VM7 porcelain. Two experimental conditions were evaluated (n = 10). For control specimens, load was applied in the center of the pontic at 0.5 mm/min until failure, using a universal testing machine, in 37°C deionized water. For mechanical cycling (MC) specimens, FPDs were subjected to MC (2 Hz, 140 N, 10(6) cycles) and subsequently tested as described for the control group. For YZ, an extra group of 10 FPDs were built with a connector cross-section of 9 mm(2) and tested until failure. Fractography and FEA were performed. Data were analyzed by ANOVA and Tukey's test (α = 0.05). YZ16 showed the greatest fracture load mean value, followed by YZ16-MC. Specimens from groups YZ9, IZ16, IZ16-MC, AL16 and AL16-MC showed no significant difference for the fracture load. The failure behavior and stress distribution of FPDs was influenced by the type of IS. AL and IZ FPDs showed similar fracture load values but different failure modes and stress distribution. YZ showed the best mechanical behavior and may be considered the material of choice to produce posterior FPDs as it was possible to obtain a good mechanical performance even with a smaller connector dimension (9 mm(2)). Copyright © 2015 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.

Methods for obtaining true particle size distributions from cross section measurements

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

Lord, Kristina Alyse

2013-01-01

Sectioning methods are frequently used to measure grain sizes in materials. These methods do not provide accurate grain sizes for two reasons. First, the sizes of features observed on random sections are always smaller than the true sizes of solid spherical shaped objects, as noted by Wicksell [1]. This is the case because the section very rarely passes through the center of solid spherical shaped objects randomly dispersed throughout a material. The sizes of features observed on random sections are inversely related to the distance of the center of the solid object from the section [1]. Second, on a planemore » section through the solid material, larger sized features are more frequently observed than smaller ones due to the larger probability for a section to come into contact with the larger sized portion of the spheres than the smaller sized portion. As a result, it is necessary to find a method that takes into account these reasons for inaccurate particle size measurements, while providing a correction factor for accurately determining true particle size measurements. I present a method for deducing true grain size distributions from those determined from specimen cross sections, either by measurement of equivalent grain diameters or linear intercepts.« less

Nuclear model calculations and their role in space radiation research

NASA Technical Reports Server (NTRS)

Townsend, L. W.; Cucinotta, F. A.; Heilbronn, L. H.

2002-01-01

Proper assessments of spacecraft shielding requirements and concomitant estimates of risk to spacecraft crews from energetic space radiation requires accurate, quantitative methods of characterizing the compositional changes in these radiation fields as they pass through thick absorbers. These quantitative methods are also needed for characterizing accelerator beams used in space radiobiology studies. Because of the impracticality/impossibility of measuring these altered radiation fields inside critical internal body organs of biological test specimens and humans, computational methods rather than direct measurements must be used. Since composition changes in the fields arise from nuclear interaction processes (elastic, inelastic and breakup), knowledge of the appropriate cross sections and spectra must be available. Experiments alone cannot provide the necessary cross section and secondary particle (neutron and charged particle) spectral data because of the large number of nuclear species and wide range of energies involved in space radiation research. Hence, nuclear models are needed. In this paper current methods of predicting total and absorption cross sections and secondary particle (neutrons and ions) yields and spectra for space radiation protection analyses are reviewed. Model shortcomings are discussed and future needs presented. c2002 COSPAR. Published by Elsevier Science Ltd. All right reserved.

Strength degradation and lifetime prediction of dental zirconia ceramics under cyclic normal loading.

PubMed

Li, Wanzhong; Xu, Yingqiang; He, Huiming; Zhao, Haidan; Sun, Jian; Hou, Yue

2015-01-01

Clinical cases show that zirconia restoration could happen fracture by accident under overloading after using a period of time. The purpose of this study is to research mechanical behavior and predict lifetime of dental zirconia ceramics under cyclic normal contact loading with experiments. Cyclic normal contact loading test and three point bending test are carried on specimens made of two brands of dental zirconia ceramic to obtain flexure strength and damage degree after different number of loading cycles. By means of damage mechanics model, damage degree under different number of contact loading cycles are calculated according to flexure strength, and verified by SEM photographs of cross section morphology of zirconia ceramics specimen phenomenologically. Relation curve of damage degree and number of cycles is fitted by polynomial fitting, then the number of loading cycles can be concluded when the specimen is complete damage. Strength degradation of two brands dental zirconia ceramics are researched in vitro, and prediction method of contact fatigue lifetime is established.

Electron tomography of HEK293T cells using scanning electron microscope-based scanning transmission electron microscopy.

PubMed

You, Yun-Wen; Chang, Hsun-Yun; Liao, Hua-Yang; Kao, Wei-Lun; Yen, Guo-Ji; Chang, Chi-Jen; Tsai, Meng-Hung; Shyue, Jing-Jong

2012-10-01

Based on a scanning electron microscope operated at 30 kV with a homemade specimen holder and a multiangle solid-state detector behind the sample, low-kV scanning transmission electron microscopy (STEM) is presented with subsequent electron tomography for three-dimensional (3D) volume structure. Because of the low acceleration voltage, the stronger electron-atom scattering leads to a stronger contrast in the resulting image than standard TEM, especially for light elements. Furthermore, the low-kV STEM yields less radiation damage to the specimen, hence the structure can be preserved. In this work, two-dimensional STEM images of a 1-μm-thick cell section with projection angles between ±50° were collected, and the 3D volume structure was reconstructed using the simultaneous iterative reconstructive technique algorithm with the TomoJ plugin for ImageJ, which are both public domain software. Furthermore, the cross-sectional structure was obtained with the Volume Viewer plugin in ImageJ. Although the tilting angle is constrained and limits the resulting structural resolution, slicing the reconstructed volume generated the depth profile of the thick specimen with sufficient resolution to examine cellular uptake of Au nanoparticles, and the final position of these nanoparticles inside the cell was imaged.

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

Zhai, Ziqing; Kruska, Karen; Toloczko, Mychailo B.

Stress corrosion crack initiation of two thermally-treated, cold-worked (CW) alloy 690 materials was investigated in 360oC simulated PWR primary water using constant load tensile (CLT) tests and blunt notch compact tension (BNCT) tests equipped with direct current potential drop (DCPD) for in-situ detection of cracking. SCC initiation was not detected by DCPD for the 21% and 31%CW CLT specimens loaded at their yield stress after ~9,220 h, however intergranular (IG) precursor damage and isolated surface cracks were observed on the specimens. The two 31%CW BNCT specimens loaded at moderate stress intensity after several cyclic loading ramps showed DCPD-indicated crack initiationmore » after 10,400h exposure at constant stress intensity, which resulted from significant growth of IG cracks. The 21%CW BNCT specimens only exhibited isolated small IG surface cracks and showed no apparent DCPD change throughout the test. Interestingly, post-test cross-section examinations revealed many grain boundary (GB) nano-cavities in the bulk of all the CLT and BNCT specimens particularly for the 31%CW materials. Cavities were also found along GBs extending to the surface suggesting an important role in crack nucleation. This paper provides an overview of the evolution of GB cavities and will discuss their effects on crack initiation in CW alloy 690.« less

Impact of the London 2012 Olympic and Paralympic Games on demand for microbiology gastrointestinal diagnostic services at the Public Health Laboratory London.

PubMed

Williams, K; Sinclair, C; McEwan, R; Fleet, K; Balasegaram, S; Manuel, R

2014-07-01

Planning for the London 2012 Olympic and Paralympic Games at the Public Health Laboratory London was based on the requirement to meet potential increased demand with scalable capacity. The aim of this study was to determine the impact on demand for microbiology gastrointestinal diagnostic services during the Games period. Retrospective cross-sectional time-series data analysis was used to assess the number of gastrointestinal specimens received in the laboratory and the number of positive results. There was no increase in the number of gastrointestinal specimens received during the Games period, thus the Games had no impact on demand for microbiology gastrointestinal diagnostic services at the laboratory. There was a decrease in the number of public health specimens received for culture [incidence rate ratio = 0.34, 95% confidence interval (CI) = 0.13-0.86, P = 0.02] and a decrease in the number of culture positive community specimens (odds ratio = 0.59, 95 % CI = 0.40-0.85, P = 0.005), suggesting a decrease in gastrointestinal illness during the Games period. As previous planning assumptions were not based on actual specimen activity, the results of this study may modify the extent of additional planning for microbiological services required for mass gatherings. © 2014 The Authors.

Analytical Chemistry and Materials Characterization Results for Debris Recovered from Nitrate Salt Waste Drum S855793

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

Martinez, Patrick Thomas; Chamberlin, Rebecca M.; Schwartz, Daniel S.

2015-09-16

Solid debris was recovered from the previously-emptied nitrate salt waste drum S855793. The bulk sample was nondestructively assayed for radionuclides in its as-received condition. Three monoliths were selected for further characterization. Two of the monoliths, designated Specimen 1 and 3, consisted primarily of sodium nitrate and lead nitrate, with smaller amounts of lead nitrate oxalate and lead oxide by powder x-ray diffraction. The third monolith, Specimen 2, had a complex composition; lead carbonate was identified as the predominant component, and smaller amounts of nitrate, nitrite and carbonate salts of lead, magnesium and sodium were also identified. Microfocused x-ray fluorescence (MXRF)more » mapping showed that lead was ubiquitous throughout the cross-sections of Specimens 1 and 2, while heteroelements such as potassium, calcium, chromium, iron, and nickel were found in localized deposits. MXRF examination and destructive analysis of fragments of Specimen 3 showed elevated concentrations of iron, which were broadly distributed through the sample. With the exception of its high iron content and low carbon content, the chemical composition of Specimen 3 was within the ranges of values previously observed in four other nitrate salt samples recovered from emptied waste drums.« less

Investigating the form-function interface in African apes: Relationships between principal moments of area and positional behaviors in femoral and humeral diaphyses.

PubMed

Carlson, Kristian J

2005-07-01

Investigations of cross-sectional geometry in nonhuman primate limb bones typically attribute shape ratios to qualitative behavioral characterizations, e.g., leaper, slow climber, brachiator, or terrestrial vs. arboreal quadruped. Quantitative positional behavioral data, however, have yet to be used in a rigorous evaluation of such shape-behavior connections. African apes represent an ideal population for such an investigation because their relatedness minimizes phylogenetic inertia, they exhibit diverse behavioral repertoires, and their locomotor behaviors are known from multiple studies. Cross-sectional data from femoral and humeral diaphyses were collected for 222 wild-shot specimens, encompassing Pan paniscus and all commonly recognized African ape subspecies. Digital representations of diaphyseal cross sections were acquired via computed tomography at three locations per diaphysis. Locomotor behaviors were pooled broadly into arboreal and terrestrial categories, then partitioned into quadrupedal walking, quadrumanous climbing, scrambling, and suspensory categories. Sex-specific taxonomic differences in ratios of principal moments of area (PMA) were statistically significant more often in the femoral diaphysis than the humeral diaphysis. While it appears difficult to relate a measure of shape (e.g., PMA ratio) to individual locomotor modes, general locomotor differences (e.g., percentage arboreal vs. terrestrial locomotion) are discerned more easily. As percentage of arboreal locomotion for a group increases, average cross sections appear more circular. Associations between PMA ratio and specific locomotor behaviors are less straightforward. Individual behaviors that integrate eccentric limb positions (e.g., arboreal scrambling) may not engender more circular cross sections than behaviors that incorporate repetitive sagittal movements (e.g., quadrupedal walking) in a straightforward manner. (c) 2004 Wiley-Liss, Inc

Valvar stenosis in truncus arteriosus.

PubMed Central

Gerlis, L M; Wilson, N; Dickinson, D F; Scott, O

1984-01-01

Twenty three morphological specimens of truncus arteriosus were examined for evidence of stenosis of the semilunar valve. One third showed good evidence of stenosis as judged by careful measurement of the valve orifice, the valve ring, and the maximum diameter of the truncus. Correlation with measured pressure gradients was poor, but angiography and cross sectional echocardiography were better predictors of stenosis. Stenosis was invariably associated with cusp dysplasia and was more common in valves with two or four cusps. Images PMID:6477783

The effect of sterilization on mechanical properties of soft tissue allografts.

PubMed

Conrad, Bryan P; Rappé, Matthew; Horodyski, MaryBeth; Farmer, Kevin W; Indelicato, Peter A

2013-09-01

One major concern regarding soft tissue allograft use in surgical procedures is the risk of disease transmission. Current techniques of tissue sterilization, such as irradiation have been shown to adversely affect the mechanical properties of soft tissues. Grafts processed using Biocleanse processing (a proprietary technique developed by Regeneration Technologies to sterilize human tissues) will have better biomechanical characteristics than tissues that have been irradiated. Fifteen pairs of cadaveric Achilles tendon allografts were obtained and separated into three groups of 10 each. Three treatment groups were: Biocleanse, Irradiated, and Control (untreated). Each specimen was tested to determine the biomechanical properties of the tissue. Specimens were cyclically preloaded and then loaded to failure in tension. During testing, load, displacement, and optical strain data were captured. Following testing, the cross sectional area of the tendons was determined. Tendons in the control group were found to have a higher extrinsic stiffness (slope of the load-deformation curve, p = .005), have a higher ultimate stress (force/cross sectional area, p = .006) and higher ultimate failure load (p = .003) than irradiated grafts. Biocleanse grafts were also found to be stiffer than irradiated grafts (p = .014) yet were not found to be statistically different from either irradiated or non-irradiated grafts in terms of load to failure. Biocleanse processing seems to be a viable alternative to irradiation for Achilles tendon allografts sterilization in terms of their biomechanical properties.

Paleohistology of Susisuchus anatoceps (Crocodylomorpha, Neosuchia): Comments on Growth Strategies and Lifestyle

PubMed Central

Sayão, Juliana M.; Bantim, Renan A. M.; Andrade, Rafael C. L. P.; Lima, Flaviana J.; Saraiva, Antônio A. F.; Figueiredo, Rodrigo G.; Kellner, Alexander W. A.

2016-01-01

Susisuchus anatoceps is a neosuchian crocodylomorph lying outside the clade Eusuchia, and associated with the transition between basal and advanced neosuchians and the rise of early eusuchians. The specimen MPSC R1136 comprises a partially articulated postcranial skeleton and is only the third fossil assigned to this relevant taxon. Thin sections of a right rib and right ulna of this specimen have been cut for histological studies and provide the first paleohistological information of an advanced non-eusuchian neosuchian from South America. The cross-section of the ulna shows a thick cortex with 17 lines of arrested growth (LAGs), a few scattered vascular canals, and primary and secondary osteons. This bone has a free medullary cavity and a spongiosa is completely absent. Thin sections of the rib show that remodeling process was active when the animal died, with a thin cortex and a well-developed spongiosa. In the latter, few secondary osteons and 4 LAGs were identified. According to the observed data, Susisuchus anatoceps had a slow-growing histological microstructure pattern, which is common in crocodylomorphs. The high number of ulnar LAGs and the active remodeling process are indicative that this animal was at least a late subadult, at or past the age of sexual maturity. This contradicts previous studies that interpreted this and other Susisuchus anatoceps specimens as juveniles, and suggests that full-grown adults of this species were relatively small-bodied, comparable in size to modern dwarf crocodiles. PMID:27149108

The Central Asiatic (Tibet, Xinjiang, Pamir) petrological collections of Sven Hedin (1865 1952) — Swedish explorer and adventurer

NASA Astrophysics Data System (ADS)

Weinberg, Roberto F.; Green, Owen R.

2002-02-01

During a 42 year period (1893-1935), the Swedish explorer Sven Hedin led and co-ordinated four expeditions to remote and inhospitable parts of Central Asia (Tibet, Xinjiang, Pamir). Along with collaborators he collected a diverse collection of just under 3100 petrological specimens. Petrographic examples of high pressure metamorphic blueschists, mantle peridotites and serpentinites, granitoids, K-rich alkaline lavas, mylonites, and a range of clastic and fossil rich carbonate sedimentary rocks are present. This collection is a major asset for scientists studying the history of continental collision between India and Asia, and the uplift of the Tibetan plateau. A spreadsheet listing all the samples collected during Hedin's first three expeditions into Tibet (commencing 1893, 1899, 1906) includes a brief description and location of each specimen, with additional information on the availability of thin sections. Samples are cross-referenced with the geographical position of Hedin's campsites indicated on maps published with his extensive reports. Most samples, and a number of thin sections, are available for loan from the Swedish Museum of Natural History, Stockholm. We also describe a smaller collection of specimens and thin sections from Hedin's fourth (1927-35, Sino-Swedish) expedition, currently housed at the Institute of Earth Sciences, Uppsala University. Hedin's career as an explorer, highlighting the geological significance of his work and the reasons that it has remained largely ignored by the majority of Himalayan and Central Asian researchers for so many years, is outlined.

Magnetic resonance imaging of the normal bovine digit.

PubMed

Raji, A R; Sardari, K; Mirmahmoob, P

2009-08-01

The purpose of this study was defining the normal structures of the digits and hoof in Holstein dairy cattle using Magnetic Resonance Image (MRI). Transverse, Sagital and Dorsoplantar MRI images of three isolated cattle cadaver digits were obtained using Gyroscan T5-NT a magnet of 0.5 Tesla and T1 Weighted sequence. The MRI images were compared to corresponding frozen cross-sections and dissect specimens of the cadaver digits. Relevant anatomical structures were identified and labeled at each level. The MRI images provided anatomical detail of the digits and hoof in Holstein dairy cattle. Transversal images provided excellent depiction of anatomical structures when compared to corresponding frozen cross-sections. The information presented in this paper would serve as an initial reference to the evaluation of MRI images of the digits and hoof in Holstein dairy cattle, that can be used by radiologist, clinicians, surgeon or for research propose in bovine lameness.

Transverse Coefficient of Thermal Expansion Measurements of Carbon Fibers Using ESEM at High Temperatures

NASA Technical Reports Server (NTRS)

Ochoa, O.; Jiang, J.; Putnam, D.; Lo, Z.; Ellis, A.; Effinger, Michael

2003-01-01

The transverse coefficient of thermal expansion (CTE) of single IM7, T1000, and P55 carbon fibers are measured at elevated temperatures. The specimens are prepared by press-fitting fiber tows into 0.7mm-diameter cavity in a graphite disk of 5mm in diameter and 3mm high. The specimens are placed on a crucible in an ESEM, and images of the fiber cross section are taken as the fibers are heated up to 800 C. Holding time, heating and cool down cycles are also introduced. The geometrical changes are measured using a graphics tablet. The change in area/perimeter is calculated to determine the strain and transverse CTE for each fiber. In a complimentary computational effort, displacements and stresses are calculated with finite element models.

The Influence of Corrosion and Cross-Section Diameter on the Mechanical Properties of B500c Steel

NASA Astrophysics Data System (ADS)

Apostolopoulos, Ch. Alk.

2009-03-01

Corrosion is a negative contributor on the structural integrity of concrete structures and leads to degradation of the mechanical properties of steel rebar. Exposure to chloride, seawater, salt and saltwater and deicing chemical environments influences the concrete-steel bond and weakens it. A considerable strength factor of the two-phase steel B500c (martensitic, ferritic-perlitic) is considered to be the outer martensitic cortex thickness, which varies according to the area of the rebar cross section. In order to evaluate the influence of corrosion and the size of the area on the mechanical properties of B500c steel, an experimental investigation was conducted on B500c ribbed steel rebar of 8, 12, 16, and 18 mm diameter, and which were artificially corroded for 10, 20, 30, 45, 60, 90, and 120 days. The laboratory tests suggest that corrosion duration and rebar cross-sectional area size had a significant impact on the strength and ductility degradation of the specimens. The tensile mechanical properties before and after corrosion indicated progressive variation and drastic drop in their values. The extended salt spray exposure enhanced the damage and created pits and notches, resulting in stress concentration points and progressive reduction of ductility and available energy. Anti-seismic design and codes that ignore the influence of the size of the cross-section area and the level of corrosion and mechanical behavior of reinforcing steel could lead to unpredictable performance during severe ground motion.

Space Shuttle AFRSI OMS pod environment test using model 81-0 test fixture in the Ames Research Center 9x7-foot supersonic wind tunnel (OS-314A/B/C)

NASA Technical Reports Server (NTRS)

Collette, J. G. R.

1984-01-01

A test was conducted in the NASA/Ames Research Center 9x7-foot Supersonic Wind Tunnel to help resolve an anomaly that developed during the STS-6 orbiter flight wherein sections of the Advanced Flexible Reusable Surface Insulation (AFRSI) covering the OMS pods suffered some damage. A one-third scale two-dimensional shell structure model of an OMS pod cross-section was employed to support the test articles. These consisted of 15 AFRSI blanket panels form-fitted over the shell structures for exposure to simulated flight conditions. Of six baseline blankets, two were treated with special surface coatings. Two other panels were configured with AFRSI sections removed from the OV099 orbiter vehicle after the STS-6 flight. Seven additional specimens incorporated alternative designs and repairs. Following a series of surface pressure calibration runs, the specimens were exposed to simulated ascent and entry dynamic pressure profiles. Entry conditions included the use of a vortex generator to evaluate the effect of shed vortices on the AFRSI located in the area of concern.

Comparing Sliding-Wear Characteristics of the Electro-Pressure Sintered and Wrought Cobalt

NASA Astrophysics Data System (ADS)

Lee, J. E.; Kim, Y. S.; Kim, T. W.

Dry sliding wear tests of hot-pressure sintered and wrought cobalt were carried out to compare their wear characteristics. Cobalt powders with average size of 1.5µm were electro-pressure sintered to make sintered-cobalt disk wear specimens. A vacuum-induction melted cobalt ingot was hot-rolled at 800°C to a plate, from which wrought-cobalt disk specimens were machined. The specimens were heat treated at various temperatures to vary grain size and phase fraction. Wear tests of the cobalt specimens were carried out using a pin-on-disk wear tester against a glass (83% SiO2) bead at 100N with the constant sliding speed and distance of 0.36m/s and 600m, respectively. Worn surfaces, their cross sections, and wear debris were examined by an SEM. The wear of the cobalt was found to be strongly influenced by the strain-induced phase transformation of ɛ-Co (hcp) to α-Co (fcc). The sintered cobalt had smaller uniform grain size and showed higher wear rate than the wrought cobalt. The higher wear rate of the sintered cobalt was explained by the more active deformation-induced phase transformation than in the wrought cobalt with larger irregular grains.

Evaluation of some properties of two fiber-reinforced composite materials.

PubMed

Lassila, Lippo V J; Tezvergil, Arzu; Lahdenperä, Milla; Alander, Pasi; Shinya, Akiyoshi; Shinya, Akikazu; Vallittu, Pekka K

2005-08-01

Water sorption, flexural properties, bonding properties, and elemental composition of photopolymerizable resin-impregnated fiber-reinforced composite (FRC) materials (everStick C&B and BR-100) (FPD) were evaluated in this study. Bar-shaped specimens (2 x 2 x 25 mm) were prepared for water sorption and flexural strength testing. The specimens (n = 6) were polymerized either with a hand light-curing unit for 40 s or, additionally, in a light-curing oven for 20 min and stored in water for 30 days. Water sorption was measured during this time, followed by measurements of flexural strength and modulus. A shear bond strength test was performed to determine the bonding characteristics of polymerized FRC to composite resin luting cement (Panavia-F), (n = 15). The cement was bonded to the FRC substrate and the specimens were thermocycled 5000 times (5-55 degrees C) in water. SEM/EDS were analyzed to evaluate the elemental composition of the glass fibers and the fiber distribution in cross section. ANOVA showed significant differences in water sorption according to brand (p < 0.05). Water sorption of everStick C&B was 1.86 wt% (hand-unit polymerized) and 1.94 wt% (oven polymerized), whereas BR-100 was 1.07 wt% and 1.17 wt%, respectively. The flexural strength of everStick C&B after 30 days' water storage was 559 MPa (hand-unit polymerized) and 796 MPa (oven-polymerized); for BR-100, the values were 547 MPa and 689 MPa, respectively. Mean shear bond strength of composite resin cement to the FRC varied between 20.1 and 23.7 MPa, showing no statistical difference between the materials. SEM/EDS analysis revealed that fibers of both FRC materials consist of the same oxides (SiO2, CaO, and Al2O3) in ratios. The distribution of fibers in the cross section of specimens was more evenly distributed in everStick C&B than in BR-100. The results of this study suggest that there are some differences in the tested properties of the FRC materials.

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

Missert, Nancy; Kotula, Paul G.; Rye, Michael

We used a focused ion beam to obtain cross-sectional specimens from both magnetic multilayer and Nb/Al-AlOx/Nb Josephson junction devices for characterization by scanning transmission electron microscopy (STEM) and energy dispersive X-ray spectroscopy (EDX). An automated multivariate statistical analysis of the EDX spectral images produced chemically unique component images of individual layers within the multilayer structures. STEM imaging elucidated distinct variations in film morphology, interface quality, and/or etch artifacts that could be correlated to magnetic and/or electrical properties measured on the same devices.

Internal Structure and Physical Properties of Ceramics at High Temperatures

DTIC Science & Technology

1975-06-01

E u u o u •H to... o c a u c u ■a c m a ai C OJ i- n HI C E 01 H ( UJO ßui) (V/UJV) 9" c C TCC) I5J50 1500 1450 1400 1350 1300...l500oC,24hr Figure 3. SEM Micrographs of the Fractured Cross Sections of SIC Specimens Oxidized in ISO torr 02- 10 - —-"■""-*« t • o e

Thermophysical Properties of Selected Rocks.

DTIC Science & Technology

1974-04-01

the region below the melting point . Selected values are for Dresser basalt based on the data of Navarro and DeWitt [861 and of Marovelli and Veith [51...TO AT = T2 - T 1, q Is the rate of heat flow, A is the cross-sectional area of the specimen, and Ax is the distance between points of temperature...heater provides a constant heat, q, per unit time and length, and the temperature at a point in the spec- imen is recorded as a function of time. The

The Mechanics of Long Bone Fractures.

DTIC Science & Technology

1981-01-31

r = .99) between wet density and ultimate bending strength for 37 specimens of human femoral bone. Evans (1973) studied embalmed human tibial...Work 2 2.2 Methods 6 2.2.1 Torsional Loading 6 2.2.2 The Effects of Combined Loading 10 2.2.3 Cancellous Bone Effects 11 2.3 Results 11 2.3.1...PROPERTIES 21 3.1 Previous Work 22 3.2 Methods 26 3.2.1 Cross Sectional Property Software 26 3.2.2 CT Scanning Procedure 28 3.2.3 Linear Dependency of

Spectroscopic characterization of collagen cross-links in bone

NASA Technical Reports Server (NTRS)

Paschalis, E. P.; Verdelis, K.; Doty, S. B.; Boskey, A. L.; Mendelsohn, R.; Yamauchi, M.

2001-01-01

Collagen is the most abundant protein of the organic matrix in mineralizing tissues. One of its most critical properties is its cross-linking pattern. The intermolecular cross-linking provides the fibrillar matrices with mechanical properties such as tensile strength and viscoelasticity. In this study, Fourier transform infrared (FTIR) spectroscopy and FTIR imaging (FTIRI) analyses were performed in a series of biochemically characterized samples including purified collagen cross-linked peptides, demineralized bovine bone collagen from animals of different ages, collagen from vitamin B6-deficient chick homogenized bone and their age- and sex-matched controls, and histologically stained thin sections from normal human iliac crest biopsy specimens. One region of the FTIR spectrum of particular interest (the amide I spectral region) was resolved into its underlying components. Of these components, the relative percent area ratio of two subbands at approximately 1660 cm(-1) and approximately 1690 cm(-1) was related to collagen cross-links that are abundant in mineralized tissues (i.e., pyridinoline [Pyr] and dehydrodihydroxylysinonorleucine [deH-DHLNL]). This study shows that it is feasible to monitor Pyr and DHLNL collagen cross-links spatial distribution in mineralized tissues. The spectroscopic parameter established in this study may be used in FTIRI analyses, thus enabling the calculation of relative Pyr/DHLNL amounts in thin (approximately 5 microm) calcified tissue sections with a spatial resolution of approximately 7 microm.

Prediction and Verification of Ductile Crack Growth from Simulated Defects in Strength Overmatched Butt Welds

NASA Technical Reports Server (NTRS)

Nishioka, Owen S.

1997-01-01

Defects that develop in welds during the fabrication process are frequently manifested as embedded flaws from lack of fusion or lack of penetration. Fracture analyses of welded structures must be able to assess the effect of such defects on the structural integrity of weldments; however, the transferability of R-curves measured in laboratory specimens to defective structural welds has not been fully examined. In the current study, the fracture behavior of an overmatched butt weld containing a simulated buried, lack-of-penetration defect is studied. A specimen designed to simulate pressure vessel butt welds is considered; namely, a center crack panel specimen, of 1.25 inch by 1.25 inch cross section, loaded in tension. The stress-relieved double-V weld has a yield strength 50% higher than that of the plate material, and displays upper shelf fracture behavior at room temperature. Specimens are precracked, loaded monotonically while load-CMOD measurements are made, then stopped and heat tinted to mark the extent of ductile crack growth. These measurements are compared to predictions made using finite element analysis of the specimens using the fracture mechanics code Warp3D, which models void growth using the Gurson-Tvergaard dilitant plasticity formulation within fixed sized computational cells ahead of the crack front. Calibrating data for the finite element analyses, namely cell size and initial material porosities are obtained by matching computational predictions to experimental results from tests of welded compact tension specimens. The R-curves measured in compact tension specimens are compared to those obtained from multi-specimen weld tests, and conclusions as to the transferability of R-curves is discussed.

Apparatus for Hot Impact Testing of Material Specimens

NASA Technical Reports Server (NTRS)

Pawlik, Ralph J.; Choi, Sung R.

2006-01-01

An apparatus for positioning and holding material specimens is a major subsystem of a system for impact testing of the specimens at temperatures up to 1,500 C. This apparatus and the rest of the system are designed especially for hot impact testing of advanced ceramics, composites, and coating materials. The apparatus includes a retaining fixture on a rotating stage on a vertically movable cross support driven by a linear actuator. These components are located below a furnace wherein the hot impact tests are performed (see Figure 1). In preparation for a test, a specimen is mounted on the retaining fixture, then the cross support is moved upward to raise the specimen, through an opening in the bottom of the furnace, to the test position inside the furnace. On one side of the furnace there is another, relatively small opening on a direct line to the specimen. Once the specimen has become heated to the test temperature, the test is performed by using an instrumented external pressurized-gas-driven gun to shoot a projectile through the side opening at the specimen.

Metal Standards for Waveguide Characterization of Materials

NASA Technical Reports Server (NTRS)

Lambert, Kevin M.; Kory, Carol L.

2009-01-01

Rectangular-waveguide inserts that are made of non-ferromagnetic metals and are sized and shaped to function as notch filters have been conceived as reference standards for use in the rectangular- waveguide method of characterizing materials with respect to such constitutive electromagnetic properties as permittivity and permeability. Such standards are needed for determining the accuracy of measurements used in the method, as described below. In this method, a specimen of a material to be characterized is cut to a prescribed size and shape and inserted in a rectangular- waveguide test fixture, wherein the specimen is irradiated with a known source signal and detectors are used to measure the signals reflected by, and transmitted through, the specimen. Scattering parameters [also known as "S" parameters (S11, S12, S21, and S22)] are computed from ratios between the transmitted and reflected signals and the source signal. Then the permeability and permittivity of the specimen material are derived from the scattering parameters. Theoretically, the technique for calculating the permeability and permittivity from the scattering parameters is exact, but the accuracy of the results depends on the accuracy of the measurements from which the scattering parameters are obtained. To determine whether the measurements are accurate, it is necessary to perform comparable measurements on reference standards, which are essentially specimens that have known scattering parameters. To be most useful, reference standards should provide the full range of scattering-parameter values that can be obtained from material specimens. Specifically, measurements of the backscattering parameter (S11) from no reflection to total reflection and of the forward-transmission parameter (S21) from no transmission to total transmission are needed. A reference standard that functions as a notch (band-stop) filter can satisfy this need because as the signal frequency is varied across the frequency range for which the filter is designed, the scattering parameters vary over the ranges of values between the extremes of total reflection and total transmission. A notch-filter reference standard in the form of a rectangular-waveguide insert that has a size and shape similar to that of a material specimen is advantageous because the measurement configuration used for the reference standard can be the same as that for a material specimen. Typically a specimen is a block of material that fills a waveguide cross-section but occupies only a small fraction of the length of the waveguide. A reference standard of the present type (see figure) is a metal block that fills part of a waveguide cross section and contains a slot, the long dimension of which can be chosen to tailor the notch frequency to a desired value. The scattering parameters and notch frequency can be estimated with high accuracy by use of commercially available electromagnetic-field-simulating software. The block can be fabricated to the requisite precision by wire electrical-discharge machining. In use, the accuracy of measurements is determined by comparison of (1) the scattering parameters calculated from the measurements with (2) the scattering parameters calculated by the aforementioned software.

Amoebiasis among patrons visiting gay saunas in Taiwan.

PubMed

Hung, C-C; Ko, N-Y; Ko, W-C; Lee, H-C; Ji, D-D; Liu, W-C; Chang, S-C

2008-10-01

This study aimed to assess the prevalence of amoebiasis among patrons visiting gay saunas in Taiwan. A cross-sectional survey was conducted using questionnaire interview and indirect hemagglutination assays and specific Entamoeba histolytica antigen assays of blood and rectal swab specimens, respectively, among patrons visiting 10 gay saunas between September 2006 and December 2006. During the three-month study period, 208 blood and 120 rectal swab specimens were tested for E. histolytica infection. Amoebiasis was detected among 3.8% and 3.3% of the patrons by serologies and antigen assays, respectively. During the latest sexual encounter, more than 70% of the patrons had oral-anogenital sex, and only 20% used condoms during oral-anogenital contact. Our findings suggest that there is a potential risk of E. histolytica transmission among the patrons visiting gay saunas who do not practise safe sex consistently in Taiwan.

Low velocity instrumented impact testing of four new damage tolerant carbon/epoxy composite systems

NASA Technical Reports Server (NTRS)

Lance, D. G.; Nettles, A. T.

1990-01-01

Low velocity drop weight instrumented impact testing was utilized to examine the damage resistance of four recently developed carbon fiber/epoxy resin systems. A fifth material, T300/934, for which a large data base exists, was also tested for comparison purposes. A 16-ply quasi-isotropic lay-up configuration was used for all the specimens. Force/absorbed energy-time plots were generated for each impact test. The specimens were cross-sectionally analyzed to record the damage corresponding to each impact energy level. Maximum force of impact versus impact energy plots were constructed to compare the various systems for impact damage resistance. Results show that the four new damage tolerant fiber/resin systems far outclassed the T300/934 material. The most damage tolerant material tested was the IM7/1962 fiber/resin system.

Precursor Evolution and Stress Corrosion Cracking Initiation of Cold-Worked Alloy 690 in Simulated Pressurized Water Reactor Primary Water

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

Zhai, Ziqing; Toloczko, Mychailo; Kruska, Karen

Stress corrosion crack initiation of two thermally-treated, cold-worked (CW) alloy 690 (UNS N06690) materials was investigated in 360oC simulated PWR primary water using constant load tensile (CLT) tests and blunt notch compact tension (BNCT) tests equipped with direct current potential drop (DCPD) for in-situ detection of cracking. SCC initiation was not detected by DCPD for either the 21% or 31%CW CLT specimens loaded at their yield stress after ~9,220 hours, however intergranular (IG) precursor damage and isolated surface cracks were observed on the specimens. The two 31%CW BNCT specimens loaded at moderate stress intensity after several cyclic loading ramps showedmore » DCPD-indicated crack initiation after 10,400 hours of exposure at constant stress intensity, which was resulted from significant growth of IG cracks. The 21%CW BNCT specimens only exhibited isolated small IG surface cracks and showed no apparent DCPD change throughout the test. Post-test cross-section examinations revealed many grain boundary (GB) nano-cavities in the bulk of all the CLT and BNCT specimens particularly for the 31%CW materials. Cavities were also found along GBs extending to the surface suggesting an important role in crack nucleation. This paper provides an overview of the evolution of GB cavities and discusses their effects on crack initiation in CW alloy 690.« less

An X-band waveguide measurement technique for the accurate characterization of materials with low dielectric loss permittivity

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

Allen, Kenneth W., E-mail: kenneth.allen@gtri.gatech.edu; Scott, Mark M.; Reid, David R.

In this work, we present a new X-band waveguide (WR90) measurement method that permits the broadband characterization of the complex permittivity for low dielectric loss tangent material specimens with improved accuracy. An electrically long polypropylene specimen that partially fills the cross-section is inserted into the waveguide and the transmitted scattering parameter (S{sub 21}) is measured. The extraction method relies on computational electromagnetic simulations, coupled with a genetic algorithm, to match the experimental S{sub 21} measurement. The sensitivity of the technique to sample length was explored by simulating specimen lengths from 2.54 to 15.24 cm, in 2.54 cm increments. Analysis ofmore » our simulated data predicts the technique will have the sensitivity to measure loss tangent values on the order of 10{sup −3} for materials such as polymers with relatively low real permittivity values. The ability to accurately characterize low-loss dielectric material specimens of polypropylene is demonstrated experimentally. The method was validated by excellent agreement with a free-space focused-beam system measurement of a polypropylene sheet. This technique provides the material measurement community with the ability to accurately extract material properties of low-loss material specimen over the entire X-band range. This technique could easily be extended to other frequency bands.« less

Study on evaluation of corrosion condition of reinforcing bar embedded concrete using infrared thermal imaging camera

NASA Astrophysics Data System (ADS)

Ruiko, Watanabe; Toshiaki, Mizobuchi

2017-04-01

Rapid aging of many concrete structures, which have been developed during rapid economic growth period in Japan, has become a serious problem for us these days. And thus, there is an urgent need to prolong their service life expectancies. For this purpose, the deterioration of reinforcing bars in the concrete structures should be detected quickly and correctly at the early stages. Nevertheless, conventional testing methods such as destructive and nondestructive testing have disadvantages: partial damages on concrete structures; difficulty with quantitative evaluation, etc. Many preceding studies have examined to estimate the deterioration of reinforcing bars based on the temperature of the concrete specimen surfaces. According to those papers, the differences in corrosion degree of reinforcing bars have a certain effect on the temperature of concrete specimen surfaces. In this study, firstly, the quantitative evaluation of the corrosion degree was conducted with 3D scanner which could measure the volume, coverage area and cross-sectional area. Secondly, the surface of the concrete specimen was cooled down with liquid nitrogen, and thirdly, thermographic change was observed up until the air temperature. Finally, the surface of the concrete specimen was detected clearly by the thermal images. As a result, this study shows that the corrosion thickness tends to get bigger, following the uprising temperature of the concrete specimen surfaces. The same kind of tendency can be observed by the thermal images, too.

Comparative evaluation of the cadaveric and computed tomographic features of the coelomic cavity in the green iguana (Iguana iguana), black and white tegu (Tupinambis merianae) and bearded dragon (Pogona vitticeps).

PubMed

Banzato, T; Selleri, P; Veladiano, I A; Zotti, A

2013-12-01

Contrast-enhanced computed tomographic studies of the coelomic cavity in four green iguanas, four black and white tegus and four bearded dragons were performed using a conventional CT scanner. Anatomical reference cross sections were obtained from four green iguana, four black and white tegu and six bearded dragon cadavers; the specimens were stored in a -20°C freezer for 24 h then sliced into 5-mm intervals. The frozen sections were cleaned with water and photographed on both sides. The individual anatomical structures were identified by means of the available literature; these were labelled first on the anatomical images and then matched to the corresponding computed tomography images. The results provide an atlas of the normal cross-sectional and computed tomographic anatomy of the coelomic cavity in the green iguana, the black and white tegu and the bearded dragon, which is useful in the interpretation of any imaging modality. © 2013 Blackwell Verlag GmbH.

Impact damage resistance of carbon/epoxy composite tubes for the DC-XA liquid hydrogen feedline

NASA Technical Reports Server (NTRS)

Nettles, A. T.

1995-01-01

Low-velocity impacts were inflicted upon two elbow sections of carbon/epoxy feedline that are to be a part of the Delta Clipper-XA flight vehicle. A soap-based liquid leak detector solution was used to inspect the impact sites for leaks of pressurized gas that was pumped into the tube. Visual surface damage was noted and recorded for each impact site. After impact testing of each of the two sections of tubes was completed, the damage zones were disected from the tube and cross sectioned through the impact site. These specimens were polished after potting them in epoxy and were examined for microcracking using a fluorescent dye penetrant technique. The results showed that nonvisible damage could cause microcracking, thereby resulting in leaks through the tube wall.

Experimental study on the effect of shape of bolt and nut on fatigue strength for bolted joint

NASA Astrophysics Data System (ADS)

Matsunari, T.; Oda, K.; Tsutsumi, N.; Yakushiji, T.; Noda, N. A.; Sano, Y.

2018-06-01

In this study, the effect of curvature radius of the thread bottom and the pitch difference between of M16 bolt and nut on fatigue strength for bolted joint is considered experimentally. The M16 bolt-nut specimens having the two kinds of thread bottom radii and the pitch differences are prepared. The S-N curves for bolted specimens with different thread shapes are obtained by the stress-controlled fatigue test (stress ratio R>0). The experimental results are compared and discussed in terms of stress analysis. The finite element method is used to make a simulation of the fatigue experiment and the mean stress and stress amplitude at each thread bottom of bolt are analysed. It is found that the initiation and propagation of crack are changed by introducing the pitch difference of α=15 μm from the crack observation in cross section of the bolt specimens after the experiment. Furthermore, the fatigue life can be extended by increasing curvature radius of thread bottom and introducing the pitch difference.

Apparatus for tensile testing plate-type ceramic specimens

DOEpatents

Liu, Kenneth C.

1993-01-01

Apparatus for tensile testing plate-type ceramic specimens having dogbone- or T-shaped end sections without introducing bending stresses in the specimens during the application of a dynamic tensile loading on the specimens is described. A pair of elongated pull rods disposed in a side-by-side relationship are used to grip the shoulders on each T-shaped end section. The pull rods are pivotally attached to a piston-displaceable, disk-shaped member so as to be longitudinally movable with respect to one another effecting the self-alignment thereof with the shoulders on the T-shaped end sections of the specimen to compensate for shoulders being located in different longitudinal positions.

Phenotypic and antibiogram pattern of V. cholerae isolates from a tertiary care hospital in Mumbai during 2004-2013: a retrospective cross-sectional study.

PubMed

Torane, V; Kuyare, S; Nataraj, G; Mehta, P; Dutta, S; Sarkar, B

2016-11-25

Cholera is a major gastroenteric disease with reports on fluctuation and resistance. Hence, the objective is to determine the trend in seasonality, resistance pattern, prevalent biotypes, serotypes and phage types between 2004 and 2013 among Vibrio cholerae isolates. A retrospective cross-sectional study. A single-centre study was carried out at a tertiary care hospital in a metropolitan city (Mumbai) of a developing country (India). Records of stool specimen cultures of patients with suspected cholera from January 2004 to December 2013 were analysed. The organisms were identified as per standard protocol. Antimicrobial susceptibility testing was performed as per Clinical Laboratory Standard Institute. Biotyping, serotyping and phage typing were carried out. From the confirmed cases of cholera, demographic and laboratory details were noted. Descriptive analysis was used and the data were presented in the form of percentages. Vibrio cholerae was predominant in males and was isolated from 9.41% (439/4664) of stool specimens. Variability was found in terms of the gross appearance of stool specimens, seasonal trend and antibiotic resistance pattern. The antimicrobial susceptibility showed a waxing and waning pattern for most of the antibiotics (ampicillin, cefuroxime, chloramphenicol, tetracycline) tested, while for a few others the strains were either uniformly sensitive (gentamicin, norfloxacin) or resistant (trimethoprim-sulfamethoxazole, nalidixic acid). All isolates belonged to subgroup O1 and biotype El Tor. The most common serotype was Ogawa. The predominant phage type was T2 (old scheme) and T27 (new scheme). The predominant biotype, serotype and phage type were El Tor, Ogawa and T27 phage, respectively. The changing trends in antimicrobial resistance pattern over the years necessitate continued epidemiological and microbiological surveillance of the disease. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/.

Experimental Study on the Growth, Coalescence and Wrapping Behaviors of 3D Cross-Embedded Flaws Under Uniaxial Compression

NASA Astrophysics Data System (ADS)

Zhou, Xiao-Ping; Zhang, Jian-Zhi; Wong, Louis Ngai Yuen

2018-05-01

The crack initiation, growth, wrapping and coalescence of two 3D pre-existing cross-embedded flaws in PMMA specimens under uniaxial compression are investigated. The stress-strain curves of PMMA specimens with 3D cross-embedded flaws are obtained. The tested PMMA specimens exhibit dominant elastic deformation and eventual brittle failure. The experimental results show that four modes of crack initiation and five modes of crack coalescence are observed. The initiations of oblique secondary crack and anti-wing crack in 3D cracking behaviors are first reported as well as the coalescence of anti-wing cracks. Moreover, two types of crack wrapping are found. Substantial wrapping of petal cracks, which includes open and closed modes of wrapping, appears to be the major difference between 2D and 3D cracking behaviors of pre-existing flaws, which are also first reported. Petal crack wraps symmetrically from either the propagated wing cracks or the coalesced wing cracks. Besides, only limited growth of petal cracks is observed, and ultimate failure of specimens is induced by the further growth of the propagated wing crack. The fracture mechanism of the tested PMMA specimens is finally revealed. In addition, the initiation stress and the peak stress versus the geometry of two 3D pre-existing cross-embedded flaws are also investigated in detail.

Design and evaluation of a foam-filled hat-stiffened panel concept for aircraft primary structural applications

NASA Technical Reports Server (NTRS)

Ambur, Damodar R.

1993-01-01

Geodesically stiffened structures are very efficient in carrying combined bending, torsion, and pressure loading that is typical of primary aircraft structures. They are also very damage tolerant since there are multiple load paths available to redistribute loads compared to prismatically stiffened structures. Geodesically stiffened structures utilize continuous filament composite materials which make them amenable to automated manufacturing processes to reduce cost. The current practice for geodesically stiffened structures is to use a solid blade construction for the stiffener. This stiffener configuration is not an efficient concept and there is a need to identify other stiffener configurations that are more efficient but utilize the same manufacturing process as the solid blade. This paper describes a foam-filled stiffener cross section that is more efficient than a solid-blade stiffener in the load range corresponding to primary aircraft structures. A prismatic hat-stiffener panel design is then selected for structural evaluation in uni-axial compression with and without impact damage. Experimental results for both single stiffener specimens and multi-stiffener panel specimens are presented. Finite element analysis results are presented that predict the buckling and postbuckling response of the test specimens. Analytical results for both the element and panel specimens are compared with experimental results.

Application of adenosine triphosphate-driven bioluminescence for quantification of plaque bacteria and assessment of oral hygiene in children.

PubMed

Fazilat, Shahram; Sauerwein, Rebecca; McLeod, Jennifer; Finlayson, Tyler; Adam, Emilia; Engle, John; Gagneja, Prashant; Maier, Tom; Machida, Curtis A

2010-01-01

Dentistry has undergone a shift in caries management toward prevention and improved oral hygiene and diagnosis. Caries prevention now represents one of the most important aspects of modern dental practice. The purpose of this cross-sectional study was to demonstrate the use of adenosine triphosphate- (ATP-) driven bioluminescence as an innovative tool for the rapid chairside enumeration of oral bacteria (including plague streptococci) and assessment of oral hygiene and caries risk. Thirty-three pediatric patients (7- to 12-year-old males and females) were examined, and plague specimens, in addition to stimulated saliva, were collected from representative teeth within each quadrant. Oral specimens (n=150 specimens) were assessed by plating on enriched and selective agars, to enumerate total bacteria and streptococci, and subjected to adenosine triphosphate- (ATP-) driven bioluminescence determinations using a luciferase-based assay system. Statistical correlations, linking ATP values to numbers of total bacteria, oral streptococci and mutans streptococci, yielded highly significant r values of 0.854, 0.840, and 0.796, respectively Our clinical data is consistent with the hypothesis that ATP measurements have a strong statistical association with bacterial number in plague and saliva specimens, including numbers for oral streptococci, and may be used as a potential assessment tool for oral hygiene and caries risk in children.

A Tensile Specimen of Tailor Rolled Blanks with Equal Probability in Yield and Its Mechanical Behavior Analysis

PubMed Central

Zhang, Sijia; Liu, Xianghua; Liu, Lizhong

2018-01-01

In this paper, the microstructure and mechanical properties that distribute regulation along the rolling direction of tailor rolled blanks (TRB) were investigated. A tensile specimen with equal probability in yield (EYS) was first designed considering variation both in thickness and in material strength. The uniaxial tension test was carried out with a digital image correlation method to analyze the mechanical behaviors. The results showed that the strain distribution of EYS was homogeneous. From the results, it can be known that a new design philosophy for a TRB tensile specimen is reasonable and EYS is suitable to characterize the mechanical behavior of TRB. The true stress-strain curves of metal in different cross sections of TRB were calculated. On the basis of the true stress-strain curves, a material model of TRB was constructed and then implemented into finite element simulations of TRB uniaxial tensile tests. The strain distribution of numerical and experimental results was similar and the error between the elongation of the specimen after fracture obtained by experiment and FE ranged from 9.51% to 13.06%. Therefore, the simulation results match well with the experimental results and the material model has high accuracy and as well as practicability. PMID:29710772

The effects of pitting on fatigue crack nucleation in 7075-T6 aluminum alloy

NASA Technical Reports Server (NTRS)

Ma, LI; Hoeppner, David W.

1994-01-01

A high-strength aluminum alloy, 7075-T6, was studied to quantitatively evaluate chemical pitting effects of its corrosion fatigue life. The study focused on pit nucleation, pit growth, and fatigue crack nucleation. Pitting corrosion fatigue experiments were conducted in 3.5 percent NaCl aqueous solution under constant amplitude sinusoidal loading at two frequencies, 5 and 20 Hz. Smooth and unnotched specimens were used in this investigation. A video recording system was developed to allow in situ observation of the surface changes of the specimens during testing. The results indicated that pitting corrosion considerably reduces the fatigue strength by accelerating fatigue crack nucleation. A metallographic examination was conducted on the specimens to evaluate the nature of corrosion pits. First, the actual shapes of the corrosion pits were evaluated by cross-sectioning the pits. Secondly, the relation between corrosion pits and microstructure was also investigated. Finally, the possibility of another corrosion mechanism that might be involved in pitting was explored in this investigation. The fractography of the tested specimens showed that corner corrosion pits were responsible for fatigue crack nucleation in the material due to the associated stress concentration. The pits exhibited variance of morphology. Fatigue life for the experimental conditions appeared to be strongly dependent on pitting kinetics and the crack nucleation stage.

Protocol for HER2 FISH Using a Non-cross-linking, Formalin-free Tissue Fixative to Combine Advantages of Cryo-preservation and Formalin Fixation

PubMed Central

Loibner, Martina; Oberauner-Wappis, Lisa; Viertler, Christian; Groelz, Daniel; Zatloukal, Kurt

2017-01-01

Morphologic assessment of formalin-fixed, paraffin-embedded (FFPE) tissue samples has been the gold standard for cancer diagnostics for decades due to its excellent preservation of morphology. Personalized medicine increasingly provides individually adapted and targeted therapies for characterized individual diseases enabled by combined morphological and molecular analytical technologies and diagnostics. Performance of morphologic and molecular assays from the same FFPE specimen is challenging because of the negative impact of formalin due to chemical modification and cross-linking of nucleic acids and proteins. A non-cross-linking, formalin-free tissue fixative has been recently developed to fulfil both requirements, i.e., to preserve morphology like FFPE and biomolecules like cryo-preservation. Since FISH is often required in combination with histopathology and molecular diagnostics, we tested the applicability of FISH protocols on tissues treated with this new fixative. We found that formalin post-fixation of histological sections of non-cross-linking, formalin-free and paraffin-embedded (NCFPE) breast cancer tissue generated equivalent results to those with FFPE tissue in human epidermal growth factor receptor 2 (HER2) FISH analysis. This protocol describes how a FISH assay originally developed and validated for FFPE tissue can be used for NCFPE tissues by a simple post-fixation step of histological sections. PMID:29364207

Device for sectioning prostatectomy specimens to facilitate comparison between histology and in vivo MRI

PubMed Central

Drew, Bryn; Jones, Edward C.; Reinsberg, Stefan; Yung, Andrew C.; Goldenberg, S. Larry; Kozlowski, Piotr

2012-01-01

Purpose To develop a device for sectioning prostatectomy specimens that would facilitate comparison between histology and in vivo MRI. Materials and methods A multi-bladed cutting device was developed, which consists of an adjustable box capable of accommodating a prostatectomy specimen up to 85 mm in size in the lateral direction, a “plunger” tool to press on the excised gland from the top to prevent it from rolling or sliding during sectioning, and a multi-bladed knife assembly capable of holding up to 21 blades at 4 mm intervals. The device was tested on a formalin fixed piece of meat and subsequently used to section a prostatectomy specimen. Histology sections were compared with T2-weighted MR images acquired in vivo prior to the prostatectomy procedure. Results The prostatectomy specimen slices were very uniform in thickness with each face parallel to the other with no visible sawing marks on the sections by the blades after the cut. MRI and histology comparison showed good correspondence between the two images. Conclusion The developed device allows sectioning of prostatectomy specimens into parallel cuts at a specific orientation and fixed intervals. Such a device is useful in facilitating accurate correlation between histology and MRI data. PMID:20882632

Design and application of a small size SAFT imaging system for concrete structure

NASA Astrophysics Data System (ADS)

Shao, Zhixue; Shi, Lihua; Shao, Zhe; Cai, Jian

2011-07-01

A method of ultrasonic imaging detection is presented for quick non-destructive testing (NDT) of concrete structures using synthesized aperture focusing technology (SAFT). A low cost ultrasonic sensor array consisting of 12 market available low frequency ultrasonic transducers is designed and manufactured. A channel compensation method is proposed to improve the consistency of different transducers. The controlling devices for array scan as well as the virtual instrument for SAFT imaging are designed. In the coarse scan mode with the scan step of 50 mm, the system can quickly give an image display of a cross section of 600 mm (L) × 300 mm (D) by one measurement. In the refined scan model, the system can reduce the scan step and give an image display of the same cross section by moving the sensor array several times. Experiments on staircase specimen, concrete slab with embedded target, and building floor with underground pipe line all verify the efficiency of the proposed method.

Anti-Stokes effect CCD camera and SLD based optical coherence tomography for full-field imaging in the 1550nm region

NASA Astrophysics Data System (ADS)

Kredzinski, Lukasz; Connelly, Michael J.

2012-06-01

Full-field Optical coherence tomography is an en-face interferometric imaging technology capable of carrying out high resolution cross-sectional imaging of the internal microstructure of an examined specimen in a non-invasive manner. The presented system is based on competitively priced optical components available at the main optical communications band located in the 1550 nm region. It consists of a superluminescent diode and an anti-stokes imaging device. The single mode fibre coupled SLD was connected to a multi-mode fibre inserted into a mode scrambler to obtain spatially incoherent illumination, suitable for OCT wide-field modality in terms of crosstalk suppression and image enhancement. This relatively inexpensive system with moderate resolution of approximately 24um x 12um (axial x lateral) was constructed to perform a 3D cross sectional imaging of a human tooth. To our knowledge this is the first 1550 nm full-field OCT system reported.

Investigation of the Leak Response of a Carbon-Fiber Laminate Loaded in Biaxial Tension

NASA Technical Reports Server (NTRS)

Jackson, Wade C.; Ratcliffe, James G.

2013-01-01

Designers of pressurized structures have been reluctant to use composite materials because of concerns over leakage. Biaxial stress states are expected to be the worst-case loading condition for allowing leakage to occur through microcracks. To investigate the leakage behavior under in-plane biaxial loading, a cruciform composite specimen was designed that would have a relatively large test section with a uniform 1:1 biaxial loading ratio. A 7.6-cm-square test section was desired for future investigations of the leakage response as a result of impact damage. Many iterations of the cruciform specimen were evaluated using finite element analysis to reduce stress concentrations and maximize the size of the uniform biaxial strain field. The final design allowed the specimen to go to relatively high biaxial strain levels without incurring damage away from the test section. The specimen was designed and manufactured using carbon/epoxy fabric with a four-ply-thick, quasi-isotropic, central test section. Initial validation and testing were performed on a specimen without impact damage. The specimen was tested to maximum biaxial strains of approximately 4500micro epsilon without apparent damage. A leak measurement system containing a pressurized cavity was clamped to the test section and used to measure the flow rate through the specimen. The leakage behavior of the specimen was investigated for pressure differences up to 172 kPa

The influence of muscle pennation angle and cross-sectional area on contact forces in the ankle joint.

PubMed

Sopher, Ran S; Amis, Andrew A; Davies, D Ceri; Jeffers, Jonathan Rt

2017-01-01

Data about a muscle's fibre pennation angle and physiological cross-sectional area are used in musculoskeletal modelling to estimate muscle forces, which are used to calculate joint contact forces. For the leg, muscle architecture data are derived from studies that measured pennation angle at the muscle surface, but not deep within it. Musculoskeletal models developed to estimate joint contact loads have usually been based on the mean values of pennation angle and physiological cross-sectional area. Therefore, the first aim of this study was to investigate differences between superficial and deep pennation angles within each muscle acting over the ankle and predict how differences may influence muscle forces calculated in musculoskeletal modelling. The second aim was to investigate how inter-subject variability in physiological cross-sectional area and pennation angle affects calculated ankle contact forces. Eight cadaveric legs were dissected to excise the muscles acting over the ankle. The mean surface and deep pennation angles, fibre length and physiological cross-sectional area were measured. Cluster analysis was applied to group the muscles according to their architectural characteristics. A previously validated OpenSim model was used to estimate ankle muscle forces and contact loads using architecture data from all eight limbs. The mean surface pennation angle for soleus was significantly greater (54%) than the mean deep pennation angle. Cluster analysis revealed three groups of muscles with similar architecture and function: deep plantarflexors and peroneals, superficial plantarflexors and dorsiflexors. Peak ankle contact force was predicted to occur before toe-off, with magnitude greater than five times bodyweight. Inter-specimen variability in contact force was smallest at peak force. These findings will help improve the development of experimental and computational musculoskeletal models by providing data to estimate force based on both surface and deep pennation angles. Inter-subject variability in muscle architecture affected ankle muscle and contact loads only slightly. The link between muscle architecture and function contributes to the understanding of the relationship between muscle structure and function.

Chicken (Gallus domesticus) inner ear afferents

NASA Technical Reports Server (NTRS)

Hara, H.; Chen, X.; Hartsfield, J. F.; Hara, J.; Martin, D.; Fermin, C. D.

1998-01-01

Neurons from the vestibular (VG) and the statoacoustic (SAG) ganglion of the chick (Gallus domesticus) were evaluated histologically and morphometrically. Embryos at stages 34 (E8 days), 39 (E13 days) and 44 (E18 days) were sacrificed and temporal bones microdissected. Specimens were embedded in JB-4 methacrylate plastic, and stained with a mixture of 0.2% toluidine blue (TB) and 0.1% basic Fuschin in 25% ethanol or with a mixture of 2% TB and 1% paraphenylenediamine (PDA) for axon and myelin measurement study. Images of the VIIIth nerve were produced by a V150 (R) color imaging system and the contour of 200-300 neuronal bodies (perikarya) was traced directly on a video screen with a mouse in real time. The cross-sectional area of VG perikarya was 67.29 micrometers2 at stage 34 (E8), 128.46 micrometers2 at stage 39 (E13) and 275.85 micrometers2 at stage 44 (E18). The cross-sectional area of SAG perikarya was 62.44 micrometers2 at stage 34 (E8), 102.05 micrometers2 at stage 39 (E13) and 165.02 micrometers2 at stage 44 (E18). A significant cross-sectional area increase of the VG perikarya between stage 39 (E13) and stage 44 (E18) was determined. We randomly measured the cross-sectional area of myelin and axoplasm of hatchling afferent nerves, and found a correspondence between axoplasmic and myelin cross-sectional area in the utricular, saccular and semicircular canal nerve branches of the nerve. The results suggest that the period between stage 34 (E8) and 39 (E13) is a critical period for afferent neuronal development. Physiological and behavioral vestibular properties of developing and maturing hatchlings may change accordingly. The results compliment previous work by other investigators and provide valuable anatomical measures useful to correlate physiological data obtained from stimulation of the whole nerve or its parts.

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

Safari, L., E-mail: laleh.safari@ist.ac.at; Department of Physics, University of Oulu, Box 3000, FI-90014 Oulu; Santos, J. P.

Atomic form factors are widely used for the characterization of targets and specimens, from crystallography to biology. By using recent mathematical results, here we derive an analytical expression for the atomic form factor within the independent particle model constructed from nonrelativistic screened hydrogenic wave functions. The range of validity of this analytical expression is checked by comparing the analytically obtained form factors with the ones obtained within the Hartee-Fock method. As an example, we apply our analytical expression for the atomic form factor to evaluate the differential cross section for Rayleigh scattering off neutral atoms.

Transmission electron microscope studies of extraterrestrial materials

NASA Technical Reports Server (NTRS)

Keller, Lindsay P.

1995-01-01

Transmission Electron Microscopy, X-Ray spectrometry and electron-energy-loss spectroscopy are used to analyse carbon in interplanetary dust particles. Optical micrographs are shown depicting cross sections of the dust particles embedded in sulphur. Selected-area electron diffraction patterns are shown. Transmission Electron Microscope specimens of lunar soil were prepared using two methods: ion-milling and ultramicrotomy. A combination of high resolution TEM imaging and electron diffraction is used to characterize the opaque assemblages. The opaque assemblages analyzed in this study are dominated by ilmenite with lesser rutile and spinel exsolutions, and traces of Fe metal.

Acousto-ultrasonic decay in metal matrix composite panels

NASA Technical Reports Server (NTRS)

Kautz, Harold E.

1995-01-01

Acousto-ultrasonic (A-U) decay rates (UD) were measured in metal matrix composite (MMC) panels. The MMC panels had fiber architectures and cross-sectional thicknesses corresponding to those designed for aerospace turbine engine structures. The wavelength-to-thickness ratio produced by the combination of experimental frequency setting conditions and specimen geometry was found to be a key parameter for identifying optimum conditions for UD measurements. The ratio was shown to be a useful rule of thumb when applied to ceramic matrix composites (CMC)s and monolithic thermo-plastics.

Energy dispersive X-ray analysis on an absolute scale in scanning transmission electron microscopy.

PubMed

Chen, Z; D'Alfonso, A J; Weyland, M; Taplin, D J; Allen, L J; Findlay, S D

2015-10-01

We demonstrate absolute scale agreement between the number of X-ray counts in energy dispersive X-ray spectroscopy using an atomic-scale coherent electron probe and first-principles simulations. Scan-averaged spectra were collected across a range of thicknesses with precisely determined and controlled microscope parameters. Ionization cross-sections were calculated using the quantum excitation of phonons model, incorporating dynamical (multiple) electron scattering, which is seen to be important even for very thin specimens. Copyright © 2015 Elsevier B.V. All rights reserved.

Viraemia and Ebola virus secretion in survivors of Ebola virus disease in Sierra Leone: a cross-sectional cohort study.

PubMed

Green, Edward; Hunt, Luke; Ross, J C Gareth; Nissen, Nina Marie; Curran, Tanya; Badhan, Anjna; Sutherland, Katherine A; Richards, Jade; Lee, James S; Allen, Samuel H; Laird, Steven; Blackman, Mandy; Collacott, Ian; Parker, Paul A; Walbridge, Andrew; Phillips, Rebecca; Sellu, Sia Jammie; Dama, Agnes; Sheriff, Alpha Karim; Zombo, Joseph; Ngegba, Doris; Wurie, Alieh H; Checchi, Francesco; Brooks, Timothy J

2016-09-01

In survivors of Ebola virus disease, clinical sequelae including uveitis, arthralgia, and fatigue are common and necessitate systematic follow-up. However, the infection risk to health-care providers is poorly defined. Here we report Ebola virus RT-PCR data for body site and fluid samples from a large cohort of Ebola virus survivors at clinic follow-up. In this cross-sectional cohort study, consecutive survivors of Ebola virus disease attending Kerry Town survivor clinic (Freetown, Sierra Leone), who had been discharged from the Kerry Town Ebola treatment unit, were invited to participate. We collected and tested axillary, blood, conjunctival, forehead, mouth, rectal, semen, urine, and vaginal specimens for presence of Ebola virus using RT-PCR. We regarded samples to be positive for Ebola virus disease if the cycle threshold was 40 or lower. We collected demographic data from survivors of their age, sex, time since discharge from the treatment unit, and length of acute admission in the Ebola treatment unit using anonymised standard forms. Between April 2, and June 16, 2015, of 151 survivors of Ebola virus disease invited to participate, 112 (74%) provided consent. The median age of participants was 21·5 years (IQR 14-31·5) with 34 (30%) participants younger than 16 years. 50 (45%) of 112 participants were male. We tested a total of 555 specimens: 103 from the axilla, 93 from blood, 92 from conjunctiva, 54 from forehead, 105 from mouth, 17 from the rectum, one from semen, 69 from urine, and 21 from the vagina. The median time from Ebola treatment unit discharge to specimen collection was 142 days (IQR 127-159). 15 participants had a total of 74 swabs taken less than 100 days from discharge. The semen sample from one participant tested positive for Ebola virus at 114 days after discharge from the treatment unit; specimens taken from the axilla, blood, conjunctiva, forehead, mouth, rectum, and urine of the same participant tested negative. All specimens from the other 111 participants tested negative. Patients recovering from Ebola virus disease who do not meet the case definition for acute disease pose a low infection risk to health-care providers 6 weeks after clearance of viraemia. Personal protective equipment after this time might be limited to standard barrier precautions, unless contact with fluids from sanctuary sites is envisaged. Save the Children International, Public Health England. Copyright © 2016 Elsevier Ltd. All rights reserved.

Understanding of the Viscoelastic Response of the Human Corneal Stroma Induced by Riboflavin/UV-A Cross-Linking at the Nano Level

PubMed Central

Labate, Cristina; De Santo, Maria Penelope; Lombardo, Giuseppe; Lombardo, Marco

2015-01-01

Purpose To investigate the viscoelastic changes of the human cornea induced by riboflavin/UV-A cross-linking using Atomic Force Microscopy (AFM) at the nano level. Methods Seven eye bank donor corneas were investigated, after gently removing the epithelium, using a commercial AFM in the force spectroscopy mode. Silicon cantilevers with tip radius of 10 nm and spring elastic constants between 26- and 86-N/m were used to probe the viscoelastic properties of the anterior stroma up to 3 µm indentation depth. Five specimens were tested before and after riboflavin/UV-A cross-linking; the other two specimens were chemically cross-linked using glutaraldehyde 2.5% solution and used as controls. The Young’s modulus (E) and the hysteresis (H) of the corneal stroma were quantified as a function of the application load and scan rate. Results The Young’s modulus increased by a mean of 1.1-1.5 times after riboflavin/UV-A cross-linking (P<0.05). A higher increase of E, by a mean of 1.5-2.6 times, was found in chemically cross-linked specimens using glutaraldehyde 2.5% (P<0.05). The hysteresis decreased, by a mean of 0.9-1.5 times, in all specimens after riboflavin/UV-A cross-linking (P<0.05). A substantial decrease of H, ranging between 2.6 and 3.5 times with respect to baseline values, was observed in glutaraldehyde-treated corneas (P<0.05). Conclusions The present study provides the first evidence that riboflavin/UV-A cross-linking induces changes of the viscoelastic properties of the cornea at the scale of stromal molecular interactions. PMID:25830534

Heavy section fracture toughness screening specimen

NASA Technical Reports Server (NTRS)

Shannon, J. L., Jr.; Donald, J. K.; Brown, W. F., Jr.

1976-01-01

Size requirements for a pin loaded double edge notch + crack tension specimen proposed for fracture toughness screening heavy section alloys were studied. Ranking of eight selected alloys based on the specimen's net strength was compared with that based on the valid plane strain fracture toughness separately determined. Performance of the specimen was judged on the basis of that comparison. The specimen's net strength was influenced by three critical specimen dimensions: distance between the crack plane and the loading hole, specimen width, and specimen thickness. Interaction between the stress fields of the crack and the loading holes reduced the net strength, but this effect disappeared as the separation reached a dimension equal to the specimen width. The effects of specimen width and thickness are interrelated and affect the net strength through their influence on the development of the crack tip plastic zone.

Materials and processes laboratory composite materials characterization task, part 1. Damage tolerance

NASA Technical Reports Server (NTRS)

Nettles, A. T.; Tucker, D. S.; Patterson, W. J.; Franklin, S. W.; Gordon, G. H.; Hart, L.; Hodge, A. J.; Lance, D. G.; Russel, S. S.

1991-01-01

A test run was performed on IM6/3501-6 carbon-epoxy in which the material was processed, machined into specimens, and tested for damage tolerance capabilities. Nondestructive test data played a major role in this element of composite characterization. A time chart was produced showing the time the composite material spent within each Branch or Division in order to identify those areas which produce a long turnaround time. Instrumented drop weight testing was performed on the specimens with nondestructive evaluation being performed before and after the impacts. Destructive testing in the form of cross-sectional photomicrography and compression-after-impact testing were used. Results show that the processing and machining steps needed to be performed more rapidly if data on composite material is to be collected within a reasonable timeframe. The results of the damage tolerance testing showed that IM6/3501-6 is a brittle material that is very susceptible to impact damage.

An examination of the damage tolerance enhancement of carbon/epoxy using an outer lamina of spectra (R)

NASA Technical Reports Server (NTRS)

Lance, D. G.; Nettles, A. T.

1991-01-01

Low velocity instrumented impact testing was utilized to examine the effects of an outer lamina of ultra-high molecular weight polyethylene (Spectra) on the damage tolerance of carbon epoxy composites. Four types of 16-ply quasi-isotropic panels (0, +45, 90, -45) were tested. Some panels contained no Spectra, while others had a lamina of Spectra bonded to the top (impacted side), bottom, or both sides of the composite plates. The specimens were impacted with energies up to 8.5 J. Force time plots and maximum force versus impact energy graphs were generated for comparison purposes. Specimens were also subjected to cross-sectional analysis and compression after impact tests. The results show that while the Spectra improved the maximum load that the panels could withstand before fiber breakage, the Spectra seemingly reduced the residual strength of the composites.

Chapter 14: Electron Microscopy on Thin Films for Solar Cells

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

Romero, Manuel; Abou-Ras, Daniel; Nichterwitz, Melanie

2016-07-22

This chapter overviews the various techniques applied in scanning electron microscopy (SEM) and transmission electron microscopy (TEM), and highlights their possibilities and also limitations. It gives the various imaging and analysis techniques applied on a scanning electron microscope. The chapter shows that imaging is divided into that making use of secondary electrons (SEs) and of backscattered electrons (BSEs), resulting in different contrasts in the images and thus providing information on compositions, microstructures, and surface potentials. Whenever aiming for imaging and analyses at scales of down to the angstroms range, TEM and its related techniques are appropriate tools. In many cases,more » also SEM techniques provide the access to various material properties of the individual layers, not requiring specimen preparation as time consuming as TEM techniques. Finally, the chapter dedicates to cross-sectional specimen preparation for electron microscopy. The preparation decides indeed on the quality of imaging and analyses.« less

Thick Concrete Specimen Construction, Testing, and Preliminary Analysis

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

Clayton, Dwight A.; Hoegh, Kyle; Khazanovich, Lev

The purpose of the U.S. Department of Energy Office of Nuclear Energy’s Light Water Reactor Sustainability (LWRS) Program is to develop technologies and other solutions that can improve the reliability, sustain the safety, and extend the operating lifetimes of nuclear power plants (NPPs) beyond 60 years. Since many important safety structures in an NPP are constructed of concrete, inspection techniques must be developed and tested to evaluate the internal condition. In-service containment structures generally do not allow for the destructive measures necessary to validate the accuracy of these inspection techniques. This creates a need for comparative testing of the variousmore » nondestructive evaluation (NDE) measurement techniques on concrete specimens with known material properties, voids, internal microstructure flaws, and reinforcement locations. A preliminary report detailed some of the challenges associated with thick reinforced concrete sections and prioritized conceptual designs of specimens that could be fabricated to represent NPP concrete structures for using in NDE evaluation comparisons. This led to the construction of the concrete specimen presented in this report, which has sufficient reinforcement density and cross-sectional size to represent an NPP containment wall. Details on how a suitably thick concrete specimen was constructed are presented, including the construction materials, final nominal design schematic, as well as formwork and rigging required to safely meet the desired dimensions of the concrete structure. The report also details the type and methods of forming the concrete specimen as well as information on how the rebar and simulated defects were embedded. Details on how the resulting specimen was transported, safely anchored, and marked to allow access for systematic comparative NDE testing of defects in a representative NPP containment wall concrete specimen are also given. Data collection using the MIRA Ultrasonic NDE equipment and initial results are also presented along with a discussion of the preliminary findings. Comparative NDE of various defects in reinforced concrete specimens is a key component in identifying the most promising techniques and directing the research and development efforts needed to characterize concrete degradation in commercial NPPs. This requires access to the specimens for data collection using state-of-the-art technology. The construction of the specimen detailed in this report allows for an evaluation of how different NDE techniques may interact with the size and complexities of NPP concrete structures. These factors were taken into account when determining specimen size and features to ensure a realistic design. The lateral dimensions of the specimen were also chosen to mitigate unrealistic boundary effects that would not affect the results of field NPP concrete testing. Preliminary results show that, while the current methods are able to identify some of the deeper defects, improvements in data processing or hardware are necessary to be able to achieve the precision and reliability achieved in evaluating thinner and less heavily reinforced concrete structures.« less

Influence of Cold-Sprayed, Warm-Sprayed, and Plasma-Sprayed Layers Deposition on Fatigue Properties of Steel Specimens

NASA Astrophysics Data System (ADS)

Cizek, J.; Matejkova, M.; Dlouhy, I.; Siska, F.; Kay, C. M.; Karthikeyan, J.; Kuroda, S.; Kovarik, O.; Siegl, J.; Loke, K.; Khor, Khiam Aik

2015-06-01

Titanium powder was deposited onto steel specimens using four thermal spray technologies: plasma spray, low-pressure cold spray, portable cold spray, and warm spray. The specimens were then subjected to strain-controlled cyclic bending test in a dedicated in-house built device. The crack propagation was monitored by observing the changes in the resonance frequency of the samples. For each series, the number of cycles corresponding to a pre-defined specimen cross-section damage was used as a performance indicator. It was found that the grit-blasting procedure did not alter the fatigue properties of the steel specimens (1% increase as compared to as-received set), while the deposition of coatings via all four thermal spray technologies significantly increased the measured fatigue lives. The three high-velocity technologies led to an increase of relative lives to 234% (low-pressure cold spray), 210% (portable cold spray), and 355% (warm spray) and the deposition using plasma spray led to an increase of relative lives to 303%. The observed increase of high-velocity technologies (cold and warm spray) could be attributed to a combination of homogeneous fatigue-resistant coatings and induction of peening stresses into the substrates via the impingement of the high-kinetic energy particles. Given the intrinsic character of the plasma jet (low-velocity impact of semi/molten particles) and the mostly ceramic character of the coating (oxides, nitrides), a hypothesis based on non-linear coatings behavior is provided in the paper.

Finite element modelling of AA6063T52 thin-walled tubes under quasi-static axial loading

NASA Astrophysics Data System (ADS)

Othman, A.; Ismail, AE

2018-04-01

The behavior of aluminum alloy 6063T52 thin walled tubes have been present in this paper to determine absorbed energy under quasi-static axial loading. The correlation and comparison have been implemented for each experimental and finite element analysis results, respectively. Wall-thickness of 1.6 and 1.9 mm were selected and all specimen tested under room temperature standard. The length of each specimen were fixed at 125 mm as well as diameter as well as a width and diameter of the tube at 50.8 mm. The two types of tubular cross-section were examined whereas a round and square thin-walled profiles. The specific absorbed energy (SEA) and crush force efficiency (CFE) were analyzed for each specimen and model to see the behavior induced to failure under progressive collapse. Result showed that a correlation less than 5% different between both of comparison experimental and finite element model. It has been found that the thin walled round tube absorbed more energy rather than square profile in term of specific energy with both of either 1.6 or 1.9 of 23.93% and 35.36%, respectively. Overall for crush force efficiency (CFE) of each tube profile around 0.42 to 0.58 value. Indicated that the all specimen profile fail under progressive damage. The calibration between deformed model and experimental specimen were examined and discussed. It was found that the similarity failure mechanism observed for each thin walled profiles.

40 CFR 792.195 - Retention of records.

Code of Federal Regulations, 2010 CFR

2010-07-01

... section, documentation records, raw data, and specimens pertaining to a study and required to be retained... records, raw data, and specimens pertaining to a study and required to be retained by this part shall be... those items listed in paragraph (c) of this section, documentation records, raw data, and specimens...

Levels of mature cross-links and advanced glycation end product cross-links in human vitreous.

PubMed

Matsumoto, Yukihiro; Takahashi, Masaaki; Chikuda, Makoto; Arai, Kiyomi

2002-01-01

To determine the levels of pyridinoline and deoxypyridinoline, two mature enzymatic cross-links, and pentosidine, an advanced glycation end product (AGE) cross-link, in the human vitreous, and to investigate the correlations among the cross-links and the effects of aging and diabetes mellitus (DM) on the levels of cross-links. Forty-five vitreous samples were collected from 32 patients (32 eyes) undergoing vitrectomy for diabetic retinopathy (DM group) and from 13 patients (13 eyes) (control group) who were age- and sex-matched patients with idiopathic macular hole or epiretinal membrane with no systemic conditions. The levels of the cross-links were determined using high-performance liquid chromatography after acid hydrolysis and pretreatment with SP-Sephadex. The levels of pentosidine, pyridinoline, and deoxypyridinoline were 27.3 +/- 23.1 (mean +/- SD) pmol/mL (detectable in 45 of 45 specimens), 79.0 +/- 40.2 ng/mL (43 of 45 specimens), and 54.0 +/- 9.5 (32 of 45 specimens) ng/mL, respectively. When the vitreous samples from the DM and the control groups were compared, a significant difference (P <.05) was found in the pentosidine level but not in the levels of pyridinoline or deoxypyridinoline. No significant correlations were found between age and the cross-links. Significant correlations (P <.01) were found among the cross-links. The results indicate that mature cross-link substances exist in the human vitreous. The results also suggest that glycation may occur in the vitreous after mature cross-links form and result in the formation of AGE cross-links. In human vitreous from patients with DM, increased levels of AGE cross-links may stabilize the formation of mature cross-links, but they did not increase the mature cross-links.

Attitudes of Australian chiropractic students toward whole body donation: a cross-sectional study.

PubMed

Alexander, Michelle; Marten, Mathew; Stewart, Ella; Serafin, Stanley; Štrkalj, Goran

2014-01-01

Cadavers play an important role in anatomy education. In Australia, bodies for anatomy education are acquired only through donations. To gain insight into educational dynamics in an anatomy laboratory as well as to facilitate body donation programs and thanksgiving ceremonies, it is important to understand students' attitudes toward body donation. In this cross-sectional study, the attitudes of Macquarie University's first, second, and fifth year chiropractic students toward body donation were investigated. Macquarie University chiropractic students have a four semester long anatomy program, which includes cadaver-based instruction on prosected specimens. A questionnaire was used to record respondents' demographics and attitudes toward body donation: personal, by a relative, and by a stranger. It was found that ethnicity and religion affect attitudes toward body donation, with Australian students being more willing to donate a stranger's body and atheists and agnostics being more willing to donate in general. Furthermore, willingness to donate one's own or a family member's body decreases as year of study increases, suggesting a possible negative impact of exposure to cadavers in the anatomy laboratory. This was only true, however, after controlling for age. Thus, the impact of viewing and handling prosected specimens, which is the norm in anatomy classes in Australia, may not be as strong as dissecting cadavers. It is suggested that anatomists and educators prepare students for cadaver-based instruction as well as exhibit sensitivity to cultural differences in how students approach working with cadavers, when informing different communities about body donation programs and in devising thanksgiving ceremonies. © 2013 American Association of Anatomists.

The Lymphatic Anatomy of the Breast and its Implications for Sentinel Lymph Node Biopsy: A Human Cadaver Study

PubMed Central

Pan, Wei-Ren; Mann, G. Bruce; Taylor, G. Ian

2007-01-01

Background Current understanding of the lymphatic system of the breast is derived mainly from the work of the anatomist Sappey in the 1850s, with many observations made during the development and introduction of breast lymphatic mapping and sentinel node biopsy contributing to our knowledge. Methods Twenty four breasts in 14 fresh human cadavers (5 male, 9 female) were studied. Lymph vessels were identified with hydrogen peroxide and injected with a lead oxide mixture and radiographed. The specimens were cross sectioned and radiographed to provide three dimensional images. Lymph (collecting) vessels were traced from the periphery to the first-tier lymph node. Results Lymph collecting vessels were found evenly spaced at the periphery of the anterior upper torso draining radially into the axillary lymph nodes. As they reached the breast some passed over and some through the breast parenchyma, as revealed in the cross-section studies. The pathways showed no significant difference between male and female specimens. We found also perforating lymph vessels that coursed beside the branches of the internal mammary vessels, draining into the ipsilateral internal mammary lymphatics. In some studies one sentinel node in the axilla drained almost the entire breast. In most more than one sentinel node was represented. Conclusion These anatomical findings are discordant with our current knowledge based on previous studies and demand closer examination by clinicians. These anatomical studies may help explain the percentage of false-negative sentinel node biopsy studies and suggest the peritumoral injection site for accurate sentinel lymph node detection. PMID:18043970

Analysis of shear test method for composite laminates

NASA Technical Reports Server (NTRS)

Bergner, H. W., Jr.; Davis, J. G., Jr.; Herakovich, C. T.

1977-01-01

An elastic plane stress finite element analysis of the stress distributions in four flat test specimens for in-plane shear response of composite materials subjected to mechanical or thermal loads is presented. The shear test specimens investigated include: slotted coupon, cross beam, losipescu, and rail shear. Results are presented in the form of normalized shear contour plots for all three in-plane stess components. It is shown that the cross beam, losipescu, and rail shear specimens have stress distributions which are more than adequate for determining linear shear behavior of composite materials. Laminate properties, core effects, and fixture configurations are among the factors which were found to influence the stress distributions.

Three-dimensional characterization of ODS ferritic steel using by FIB-SEM serial sectioning method.

PubMed

Endo, T; Sugino, Y; Ohono, N; Ukai, S; Miyazaki, N; Wang, Y; Ohnuki, S

2014-11-01

Considerable attention has been paid to the research of the electron tomography due to determine the three-dimensional (3D) structure of materials [1]. One of the electron tomography techniques, focused ion beam/scanning electron microscopy (FIB-SEM) imaging has advantages of high resolutions (10 nm), large area observation (μm order) and simultaneous energy dispersive x- ray microanalysis (EDS)/ electron backscatter diffraction (EBSD) analysis. The purpose of this study, three-dimensional EBSD analysis of ODS ferritic steel which carried out cold work using FIB-SEM equipment was conducted, and it aimed at analyzing the microstructure obtained there. The zone annealing tests were conducted for ferritic steel [2,3], which were produced through mechanical alloying and hot-extrusion. After zone annealing, specimens were mechanically polished with #400∼4000 emery paper, 1 µm diamond paste and alumina colloidal silica. The serial sectioning and the 3D-electron backscattering diffraction (3D-EBSD) analysis were carried out. We made the micro pillar (30 x 30 x 15 µm). The EBSD measurements were carried out in each layer after serial sectioning at a step size and milling depth was 80 nm with 30 slices. After EBSD analysis, the series of cross-sectional images were aligned according to arbitrarily specified areas and then stacked up to form a volume. Consequently, we obtained the 3D-IPF maps for ODS ferritic steel. In this specimen, the {111} and {001} grains are layered by turns. In addition, the volume fraction value of both plane are similar. The aspect ratio increases with specimen depth. The 3D-EBSD mapping is useful to analysis of the bulk material since this method obtain many microstructure information, such a shape, volume and orientation of the crystal, grain boundary. © The Author 2014. Published by Oxford University Press on behalf of The Japanese Society of Microscopy. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Development and Clinical Evaluation of a Recombinant-Antigen-Based Cytomegalovirus Immunoglobulin M Automated Immunoassay Using the Abbott AxSYM Analyzer

PubMed Central

Maine, G. T.; Stricker, R.; Schuler, M.; Spesard, J.; Brojanac, S.; Iriarte, B.; Herwig, K.; Gramins, T.; Combs, B.; Wise, J.; Simmons, H.; Gram, T.; Lonze, J.; Ruzicki, D.; Byrne, B.; Clifton, J. D.; Chovan, L. E.; Wachta, D.; Holas, C.; Wang, D.; Wilson, T.; Tomazic-Allen, S.; Clements, M. A.; Wright, G. L.; Lazzarotto, T.; Ripalti, A.; Landini, M. P.

2000-01-01

A new microparticle enzyme immunoassay (MEIA), the Cytomegalovirus (CMV) Immunoglobulin M (IgM) test, was developed on the Abbott AxSYM analyzer. This test uses recombinant CMV antigens derived from portions of four structural and nonstructural proteins of CMV: pUL32 (pp150), pUL44 (pp52), pUL83 (pp65), and pUL80a (pp38). A total of 1,608 specimens from random volunteer blood donors (n = 300), pregnant women (n = 1,118), transplant recipients (n = 6), and patients with various clinical conditions and disease states (n = 184) were tested during development and evaluation of this new assay. In a preliminary clinical evaluation we tested specimens collected prospectively from pregnant women (n = 799) and selected CMV IgM-positive archived specimens from pregnant women (n = 39). The results from the new CMV IgM immunoassay were compared to the results of a consensus interpretation of the results obtained with three commercial CMV IgM immunoassays. The results for specimens with discordant results were resolved by a CMV IgM immunoblot assay. The relative sensitivity, specificity, and agreement for the AxSYM CMV IgM assay were 94.29, 96.28, and 96.19%, respectively, and the resolved sensitivity, specificity, and agreement were 95.83, 97.47, and 97.37%, respectively. We also tested serial specimens from women who experienced seroconversion or a recent CMV infection during gestation (n = 17) and potentially cross-reactive specimens negative for CMV IgM antibody by the consensus tests (n = 184). The AxSYM CMV IgM assay was very sensitive for the detection of CMV IgM during primary CMV infection, as shown by the detection of CMV IgM at the same time as or just prior to the detection of CMV IgG. Specimens from individuals with lupus (n = 16) or parvovirus B19 infection (n = 6) or specimens containing hyper IgM (n = 9), hyper IgG (n = 8), or rheumatoid factor (n = 55) did not cross-react with the AxSYM assay. One specimen each from individuals infected with Epstein-Barr virus (n = 26), measles virus (n = 10), herpes simplex virus (n = 12), or varicella-zoster virus (n = 13) infection, one specimen from an influenza vaccinee (n = 14), and one specimen containing antinuclear antibody cross-reacted with the assay. The overall rate of cross-reactivity of the specimens with the assay was 3.3% (6 of 184). The AxSYM CMV IgM assay is a sensitive and specific assay for the detection of CMV-specific IgM. PMID:10747129

Corrosion behavior of an HVOF-sprayed Fe3Al coating in a high-temperature oxidizing/sulfidizing environment

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

Covino, Bernard S., Jr.; Bullard, Sophie J.; Cramer, Stephen D.

An iron aluminide (Fe3Al) intermetallic coating was deposited onto a F22 (2.25Cr-1Mo) steel substrate using a JP-5000 high velocity oxy-fuel (HVOF) thermal spray system. The as-sprayed coating was examined by electron microscopy and X-ray diffraction and was characterized in terms of oxidation and adhesion. Fe3Al-coated steel specimens were exposed to a mixed oxidizing/sulfidizing environment at 500, 600, 700, and 800DGC for approximately seven days. The gaseous environment consisted of N2-10%CO-5%CO2-2%H2O-0.12%H2S (by volume). All specimens gained mass after exposure to the environment and the mass gains were found to be inversely proportional to temperature increases. Representative specimens exposed at each temperaturemore » were cross-sectioned and subjected to examination under a scanning electron microscope (SEM) and X-ray mapping. Results are presented in terms of corrosion weight gain and corrosion product formation. The purpose of the research presented here was to evaluate the effectiveness of an HVOF-sprayed Fe3Al coating in protecting a steel substrate exposed to a fossil energy environment.« less

Oral Chlamydia trachomatis in Patients with Established Periodontitis

PubMed Central

Reed, Susan G.; Lopatin, Dennis E.; Foxman, Betsy; Burt, Brian A.

2009-01-01

Periodontitis is considered a consequence of a pathogenic microbial infection at the periodontal site and host susceptibility factors. Periodontal research supports the association of Actinobacillus actinomycetemcomitans, Porphyromonas gingivalis, Prevotella intermedia, and Bacteroides forsythus, and periodontitis; however causality has not been demonstrated. In pursuit of the etiology of periodontitis, we hypothesized that the intracellular bacteria, Chlamydia trachomatis, may play a role. As a first step, a cross-sectional study of dental school clinic patients with established periodontitis were assessed for the presence of C. trachomatis in the oral cavity, and in particular from the lining epithelium of periodontal sites. C. trachomatis was detected using a direct fluorescent monoclonal antibody (DFA) in oral specimens from 7% (6/87) of the patients. Four patients tested positive in specimens from the lining epithelium of diseased periodontal sites, one patient tested positive in healthy periodontal sites, and one patient tested positive in the general mucosal specimen. In conclusion, this study provides preliminary evidence of C. trachomatis in the periodontal sites. Planned studies include the use of a more precise periodontal epithelial cell collection device, the newer nucleic acid amplification techniques to detect C. trachomatis, and additional populations to determine the association of C. trachomatis and periodontitis. PMID:11218493

Ultrasonic linear array validation via concrete test blocks

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

Hoegh, Kyle, E-mail: hoeg0021@umn.edu; Khazanovich, Lev, E-mail: hoeg0021@umn.edu; Ferraro, Chris

2015-03-31

Oak Ridge National Laboratory (ORNL) comparatively evaluated the ability of a number of NDE techniques to generate an image of the volume of 6.5′ X 5.0′ X 10″ concrete specimens fabricated at the Florida Department of Transportation (FDOT) NDE Validation Facility in Gainesville, Florida. These test blocks were fabricated to test the ability of various NDE methods to characterize various placements and sizes of rebar as well as simulated cracking and non-consolidation flaws. The first version of the ultrasonic linear array device, MIRA [version 1], was one of 7 different NDE equipment used to characterize the specimens. This paper dealsmore » with the ability of this equipment to determine subsurface characterizations such as reinforcing steel relative size, concrete thickness, irregularities, and inclusions using Kirchhoff-based migration techniques. The ability of individual synthetic aperture focusing technique (SAFT) B-scan cross sections resulting from self-contained scans are compared with various processing, analysis, and interpretation methods using the various features fabricated in the specimens for validation. The performance is detailed, especially with respect to the limitations and implications for evaluation of a thicker, more heavily reinforced concrete structures.« less

Revised generic placement of Brachypelma embrithes (Chamberlin & Ivie, 1936) and Brachypelma angustum Valerio, 1980, with definition of the taxonomic features for identification of female Sericopelma Ausserer, 1875 (Araneae, Theraphosidae)

PubMed Central

Gabriel, Ray; Longhorn, Stuart J.

2015-01-01

Abstract The tarantula genus Sericopelma was originally defined based on male specimens, most notably lacking tibial spurs on leg I. Early female specimens were unrecognised as Sericopelma, and typically placed in Eurypelma – a dumping ground for problem specimens. The first females were only later recognised, but authors failed to adequately define female Sericopelma. Here, the holotypes of the southern-most alleged Brachypelma species, Brachypelma embrithes (Chamberlin & Ivie, 1936) and Brachypelma angustum Valerio, 1980 were examined, and finding both to possess defining characteristics of Sericopelma were transferred. The taxonomic attributes to define Sericopelma relative to Brachypelma and select other Neotropical genera are discussed, especially for females. As important diagnostic characters for Sericopelma, the single (unilobar) spermathecae swollen at the apex forming a P-shaped cross-section, metatarsus IV with trace scopula, femur IV with a dense retrolateral pad of plumose hair, plus other attributes. Some past confusion in these characters are clarified and Sericopelma relative to Brachypelma and Megaphobema mesomelas are discussed. Finally recommendations are given about these taxonomic changes for CITES regulations. PMID:26487826

Cranial morphology of Sinovenator changii (Theropoda: Troodontidae) on the new material from the Yixian Formation of western Liaoning, China.

PubMed

Yin, Ya-Lei; Pei, Rui; Zhou, Chang-Fu

2018-01-01

A new three-dimensionally preserved troodontid specimen consisting of most of the skull, partial mandibles and six articulated cervical vertebrae (PMOL-AD00102) from the Early Cretaceous Yixian Formation of Beipiao, western Liaoning, China is identified as Sinovenator changii on the basis of a surangular with a "T"-shaped cross-section. High-resolution computed tomographic data for the skull of this new specimen facilitated a detailed description of the cranial anatomy of S. changii . New diagnostic features of S. changii include a well-developed medial shelf on the jugal, a slender bar in the parasphenoid recess, a lateral groove on the pterygoid flange of the ectopterygoid, and the lateral surface of the anterior cervical vertebrae bearing two pneumatic foramina. Our new observation confirms that the braincase of Sinovenator is not as primitive as previously suggested, although it still shows an intermediate state between derived troodontids and non-troodontid paravians in having an initial stage of the subotic recess and the otosphenoidal crest. Additionally, this new specimen reveals some novel and valuable anatomical information of troodontids regarding the quadrate-quadratojugal articulation, the stapes, the epipterygoid and the atlantal ribs.

Study on the Factors Affecting the Mechanical Behavior of Electron Beam Melted Ti6Al4V

NASA Astrophysics Data System (ADS)

Pirozzi, Carmine; Franchitti, Stefania; Borrelli, Rosario; Caiazzo, Fabrizia; Alfieri, Vittorio; Argenio, Paolo

2017-09-01

In this study, a mechanical characterization has been performed on EBM built Ti-6Al-4V tensile samples. The results of tensile tests have shown a different behavior between two sets of specimens: as built and machined ones. Supporting investigations have been carried out in order to physically explain the statistical difference of mechanical performances. Cylindrical samples which represent the tensile specimens geometry have been EBM manufactured and then investigated in their as built conditions from macrostructural and microstructural point of view. In order to make robust this study, cylindrical samples have been EBM manufactured with different size and at different height from build plate. The reason of this choice was arisen from the need of understanding if other factors as the massivity and specific location could affect the microstructure and defects generations consequently influencing the mechanical behavior of the EBMed components. The results of this study have proved that the irregularity of external circular surfaces of examined cylinders, reducing significantly the true cross section withstanding the applied load, has given a comprehensive physical explanation of the different tensile behavior of the two sets of tensile specimens.

Evaluation of the amalgamation reaction of experimental Ag-Sn-Cu alloys containing Pd using a mercury plating technique.

PubMed

Koike, Marie; Ferracane, Jack L; Fujii, Hiroyuki; Okabe, Toru

2003-09-01

A mercury plating technique was used to determine the phases forming on experimental Ag-Sn-Cu alloy powders (with and without Pd) exposed to electrolytically deposited mercury. Four series of alloy powders were made: a) 1.5% Pd with 10-14% Cu (CU series); b) 1.0% Pd with 10-14% Cu (1PD series); c) 1.5% Pd with different ratios of Ag3Sn (gamma) to Ag4Sn (beta) with 12% Cu (AGSN series); and d) 9-13% Cu with no Pd (NOPD series). Each powder was pressed on a freshly prepared amalgam specimen made from the same powder and metallographically polished until cross sections appeared; mercury was electroplated on the alloy particles. Alloy powders, amalgams and electroplated specimens were examined using XRD and SEM/EDS. XRD confirmed the presence of gamma2 in amalgams made from alloys with Cu < 13% or with Ag3Sn/Ag4Sn > 0.8. Specimens with moderately plated Hg showed gamma1 (Ag2Hg3) polyhedra and eta' Cu6Sn5, but not gamma2. This method effectively identifies alloys prone to forming gamma2.

Nano-indentation investigation on the mechanical stability of individual austenite in high-carbon steel

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

Qiao, Xun; Han, Lizhan; Zhang, Weimin

2015-12-15

Quenching (AQ) and cryogenic treatments (QC) were conducted on the high-carbon SAE 52100 steel to investigate the mechanical stability of individual retained austenite (RA) by nano-indentation. The cross-sections of indented RA region prepared by focused ion beam (FIB) were examined by using transmission electron microscopy (TEM). For the first time, it was directly observed that some parts of RA grain, closest to the indent, in AQ specimen had transformed into strain-induced martensite (SIM). However, not any pop-in or transformation was detected in the indented QC specimen. This clearly indicates that the mechanical stability of RA in QC seems significantly enhanced,more » which is mainly attributed to the cryogenic treatment resulting in a higher carbon enrichment of RA compared to that in AQ. Furthermore, a higher load of external stress may need to trigger its martensitic transformation in QC specimen. - Highlights: • Mechanical stability of retained austenite was studied by nano-indentation and TEM. • The strain-induced martensite transformation in RA was observed under applied load. • Cryogenic treatment enhances mechanical stability of RA due to carbon enrichment.« less

An audit of intraoperative frozen section in Johor.

PubMed

Khoo, J J

2004-03-01

A 4-year-review was carried out on intraoperative frozen section consultations in Sultanah Aminah Hospital, Johor Bahru. Two hundred and fifteen specimens were received from 79 patients in the period between January 1999 and December 2002. An average of 2.72 specimens per patient was received. The overall diagnostic accuracy was high, 97.56%. The diagnoses were deferred in 4.65% of the specimens. False positive diagnoses were made in 3 specimens (1.46%) and false negative diagnoses in 2 specimens (0.98%). This gave an error rate of 2.44%. The main cause of error was incorrect interpretation of the pathologic findings. In the present study, frozen sections showed good sensitivity (97.98%) and specificity (97.16%). Despite its limitations, frozen section is still generally considered to be an accurate mode of intraoperative consultation to assist the surgeon in deciding the best therapeutic approach for his patient at the operating table. The use of frozen section with proper indications was cost-effective as it helped lower the number of reoperations. An audit of intraoperative frozen section from time to time serves as part of an ongoing quality assurance program and should be recommended where the service is available.

Glaucoma-related Changes in the Mechanical Properties and Collagen Micro-architecture of the Human Sclera

PubMed Central

Coudrillier, Baptiste; Pijanka, Jacek K.; Jefferys, Joan L.; Goel, Adhiraj; Quigley, Harry A.; Boote, Craig; Nguyen, Thao D.

2015-01-01

Objective The biomechanical behavior of the sclera determines the level of mechanical insult from intraocular pressure to the axons and tissues of the optic nerve head, as is of interest in glaucoma. In this study, we measure the collagen fiber structure and the strain response, and estimate the material properties of glaucomatous and normal human donor scleras. Methods Twenty-two posterior scleras from normal and diagnosed glaucoma donors were obtained from an eyebank. Optic nerve cross-sections were graded to determine the presence of axon loss. The specimens were subjected to pressure-controlled inflation testing. Full-field displacement maps were measured by digital image correlation (DIC) and spatially differentiated to compute surface strains. Maps of the collagen fiber structure across the posterior sclera of each inflated specimen were obtained using synchrotron wide-angle X-ray scattering (WAXS). Finite element (FE) models of the posterior scleras, incorporating a specimen-specific representation of the collagen structure, were constructed from the DIC-measured geometry. An inverse finite element analysis was developed to estimate the stiffness of the collagen fiber and inter-fiber matrix. Results The differences between glaucoma and non-glaucoma eyes were small in magnitude. Sectorial variations of degree of fiber alignment and peripapillary scleral strain significantly differed between normal and diagnosed glaucoma specimens. Meridional strains were on average larger in diagnosed glaucoma eyes compared with normal specimens. Non-glaucoma specimens had on average the lowest matrix and fiber stiffness, followed by undamaged glaucoma eyes, and damaged glaucoma eyes but the differences in stiffness were not significant. Conclusion The observed biomechanical and microstructural changes could be the result of tissue remodeling occuring in glaucoma and are likely to alter the mechanical environment of the optic nerve head and contribute to axonal damage. PMID:26161963

Tensile testing method for rare earth based bulk superconductors at liquid nitrogen temperature

NASA Astrophysics Data System (ADS)

Kasaba, K.; Katagiri, K.; Murakami, A.; Sato, G.; Sato, T.; Murakami, M.; Sakai, N.; Teshima, H.; Sawamura, M.

2005-10-01

Bending tests have been commonly carried out to investigate the mechanical properties of melt-processed rare earth based bulk superconductors. Tensile tests by using small specimen, however, are preferable to evaluate the detailed distribution of the mechanical properties and the intrinsic elastic modulus because no stress distributions exist in the cross-section. In this study, the tensile test method at low temperature by using specimens with the dimensions of 3 × 3 × 4 mm from Y123 and Gd123 bulks was examined. They were glued to Al alloy rods at 400 K by using epoxy resin. Tests were carried out at liquid nitrogen temperature (LNT) by using the immersion type jig. Although the bending strength in the direction perpendicular to the c-axis of the bulks at LNT is higher than that at room temperature (RT), the tensile strength at LNT was lower than that at RT. Many of specimens fractured near the interface between the specimen and the Al alloy rod at LNT. According to the finite element method analysis, it was shown that there was a peak thermal stress in the loading direction near the interface and it was significantly higher at LNT than that at RT. It was also shown that the replacement of the Al alloy rod to Ti rod of which the coefficient of thermal expansion is close to that of bulks significantly increased the tensile strength.

The Fire Resistance Performance of Recycled Aggregate Concrete Columns with Different Concrete Compressive Strengths

PubMed Central

Dong, Hongying; Cao, Wanlin; Bian, Jianhui; Zhang, Jianwei

2014-01-01

In order to ascertain the fire resistance performance of recycled aggregate concrete (RAC) components with different concrete compressive strengths, four full-scaled concrete columns were designed and tested under high temperature. Two of the four specimens were constructed by normal concrete with compressive strength ratings of C20 and C30, respectively, while the others were made from recycled coarse aggregate (RCA) concrete of C30 and C40, respectively. Identical constant axial forces were applied to specimens while being subjected to simulated building fire conditions in a laboratory furnace. Several parameters from the experimental results were comparatively analyzed, including the temperature change, vertical displacement, lateral deflection, fire endurance, and failure characteristics of specimens. The temperature field of specimens was simulated with ABAQUS Software (ABAQUS Inc., Provindence, RI, USA) and the results agreed quite well with those from the experiments. Results show that the rate of heat transfer from the surface to the interior of the column increases with the increase of the concrete’s compressive strength for both RAC columns and normal concrete columns. Under the same initial axial force ratio, for columns with the same cross section, those with lower concrete compressive strengths demonstrate better fire resistance performance. The fire resistance performance of RAC columns is better than that of normal concrete columns, with the same concrete compressive strength. PMID:28788279

The Fire Resistance Performance of Recycled Aggregate Concrete Columns with Different Concrete Compressive Strengths.

PubMed

Dong, Hongying; Cao, Wanlin; Bian, Jianhui; Zhang, Jianwei

2014-12-08

In order to ascertain the fire resistance performance of recycled aggregate concrete (RAC) components with different concrete compressive strengths, four full-scaled concrete columns were designed and tested under high temperature. Two of the four specimens were constructed by normal concrete with compressive strength ratings of C20 and C30, respectively, while the others were made from recycled coarse aggregate (RCA) concrete of C30 and C40, respectively. Identical constant axial forces were applied to specimens while being subjected to simulated building fire conditions in a laboratory furnace. Several parameters from the experimental results were comparatively analyzed, including the temperature change, vertical displacement, lateral deflection, fire endurance, and failure characteristics of specimens. The temperature field of specimens was simulated with ABAQUS Software (ABAQUS Inc., Provindence, RI, USA) and the results agreed quite well with those from the experiments. Results show that the rate of heat transfer from the surface to the interior of the column increases with the increase of the concrete's compressive strength for both RAC columns and normal concrete columns. Under the same initial axial force ratio, for columns with the same cross section, those with lower concrete compressive strengths demonstrate better fire resistance performance. The fire resistance performance of RAC columns is better than that of normal concrete columns, with the same concrete compressive strength.

An Experimental Study on Shrinkage Strains of Normal-and High-Strength Concrete-Filled Frp Tubes

NASA Astrophysics Data System (ADS)

Vincent, Thomas; Ozbakkaloglu, Togay

2017-09-01

It is now well established that concrete-filled fiber reinforced polymer (FRP) tubes (CFFTs) are an attractive construction technique for new columns, however studies examining concrete shrinkage in CFFTs remain limited. Concrete shrinkage may pose a concern for CFFTs, as in these members the curing of concrete takes place inside the FRP tube. This paper reports the findings from an experimental study on concrete shrinkage strain measurements for CFFTs manufactured with normal- and high-strength concrete (NSC and HSC). A total of 6 aramid FRP (AFRP)-confined concrete specimens with circular cross-sections were manufactured, with 3 specimens each manufactured using NSC and HSC. The specimens were instrumented with surface and embedded strain gauges to monitor shrinkage development of exposed concrete and concrete sealed inside the CFFTs, respectively. All specimens were cylinders with a 152 mm diameter and 305 mm height, and their unconfined concrete strengths were 44.8 or 83.2 MPa. Analysis of the shrinkage measurements from concrete sealed inside the CFFTs revealed that embedment depth and concrete compressive strength only had minor influences on recorded shrinkage strains. However, an analysis of shrinkage measurements from the exposed concrete surface revealed that higher amounts of shrinkage can occur in HSC. Finally, it was observed that shrinkage strains are significantly higher for concrete exposed at the surface compared to concrete sealed inside the CFFTs.

Bond durability of adhesives containing modified-monomer with/without-fluoride after aging in artificial saliva and under intrapulpal pressure simulation.

PubMed

El-Deeb, H A; Al Sherbiney, H H; Mobarak, E H

2013-01-01

To evaluate the dentin bond strength durability of adhesives containing modified-monomer with/without-fluoride after storage in artificial saliva and under intrapulpal pressure simulation (IPPS). The occlusal enamel of 48 freshly extracted teeth was trimmed to expose midcoronal dentin. Roots were sectioned to expose the pulp chamber and to connect the specimens to the pulpal-pressure assembly. Specimens were assigned into four groups (n=12) according to adhesive system utilized: a two-step etch-and-rinse adhesive system (SB, Adper Single Bond 2, 3M ESPE), a two-step self-etch adhesive system (CSE, Clearfil SE Bond, Kuraray Medical Inc), and two single-step self-etch adhesives with the same modified monomer (bis-acrylamide)-one with fluoride (AOF, AdheSE One F, Ivoclar-Vivadent) and the other without (AO, AdheSE One, Ivoclar-Vivadent). Bonding was carried out while the specimens were subjected to 15-mm Hg IPPS. Resin composite (Valux Plus, 3M ESPE) buildups were made. After curing, specimens were aged in artificial saliva and under 20-mm Hg IPPS at 37°C in a specially constructed incubator either for 24 hours or six months prior to testing. Bonded specimens (n=6/group) were sectioned into sticks (n=24/group) with a cross section of 0.9 ± 0.01 mm(2) and subjected to microtensile bond strength (μTBS) testing using a universal testing machine. Data were statistically analyzed using two-way analysis of variance (ANOVA) with repeated measures, one-way ANOVA tests, and a t-test (p<0.05). Failure modes were determined using a scanning electron microscope. The μTBS values of SB and CSE fell significantly after six-month storage in artificial saliva and under IPPS, yet these values remained significantly higher than those for the other two adhesives with modified monomers. There was no significant difference in the bond strength values between fluoride-containing and fluoride-free self-etch adhesive systems (AOF and AO) after 24 hours or six months. Modes of failure were mainly adhesive and mixed. Based on the results of this study, 1) Fluoride addition did not affect dentin bond durability; and 2) despite the fact that the single-step adhesive system with modified monomer showed stability, bond strengths associated with these systems remained lower than those of multistep adhesive systems.

Analysis of Multilayer Devices for Superconducting Electronics by High-Resolution Scanning Transmission Electron Microscopy and Energy Dispersive Spectroscopy

DOE PAGES

Missert, Nancy; Kotula, Paul G.; Rye, Michael; ...

2017-02-15

We used a focused ion beam to obtain cross-sectional specimens from both magnetic multilayer and Nb/Al-AlOx/Nb Josephson junction devices for characterization by scanning transmission electron microscopy (STEM) and energy dispersive X-ray spectroscopy (EDX). An automated multivariate statistical analysis of the EDX spectral images produced chemically unique component images of individual layers within the multilayer structures. STEM imaging elucidated distinct variations in film morphology, interface quality, and/or etch artifacts that could be correlated to magnetic and/or electrical properties measured on the same devices.

Effect of matrix resin on the impact fracture characteristics of graphite-epoxy laminates

NASA Technical Reports Server (NTRS)

Hertzberg, P. E.; Smith, B. W.; Miller, A. G.

1982-01-01

The effect of resin chemistry on basic impact energy absorbent mechanisms exibited by graphite-epoxy composites was investigated. Impact fracture modes and microscopic resin deformation characteristics were examined for 26 NASA-impacted graphite epoxy laminates with different resin chemistries. Discrete specimen fracture modes were identified through cross sectional examination after impact, and subsequently compared with measured glass transition temperatures, cure cycles, and residual impact capabilities. Microscopic resin deformation mechanisms and their overall relationship to impact loading conditions, voids, and resin content were also characterized through scanning electron microscopic examination of separated fracture surfaces.

Formation of 2D nanoparticles with block structure in simultaneous electric explosion of conductors

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

Kryzhevich, Dmitrij S., E-mail: kryzhev@ispms.ru, E-mail: kost@ispms.ru; Zolnikov, Konstantin P., E-mail: kryzhev@ispms.ru, E-mail: kost@ispms.ru; Abdrashitov, Andrei V.

2014-11-14

A molecular dynamics simulation of nanoparticle formation in simultaneous electric explosion of conductors is performed. Interatomic interaction is described using potentials calculated in the framework of the embedded atom method. High-rate heating results in failure of the conductors with the formation of nanoparticles. The influence of the heating rate, temperature distribution over the specimen cross-section and the distance between simultaneously exploded conductors on the structure of formed nanoparticles is studied. The calculation results show that the electric explosion of conductors allows the formation of nanoparticles with block structure.

A method of predicting the energy-absorption capability of composite subfloor beams

NASA Technical Reports Server (NTRS)

Farley, Gary L.

1987-01-01

A simple method of predicting the energy-absorption capability of composite subfloor beam structure was developed. The method is based upon the weighted sum of the energy-absorption capability of constituent elements of a subfloor beam. An empirical data base of energy absorption results from circular and square cross section tube specimens were used in the prediction capability. The procedure is applicable to a wide range of subfloor beam structure. The procedure was demonstrated on three subfloor beam concepts. Agreement between test and prediction was within seven percent for all three cases.

Hygrothermal Properties of Cross Laminated Timber and Moisture Response of Wood at High Relative Humidity

NASA Astrophysics Data System (ADS)

AlSayegh, George

Cross Laminated Timber (CLT) is a new wood-based material composed of cross laminated wood boards that form a structural panel. This study focuses on identifying the appropriate methods to determine the hygrothermal properties of CLTs fabricated with Canadian and European Lumber. The laboratory tests carried out in this study will help establish heat, air and moisture response properties to be used for hygrothermal simulation to assess the durability of CLTs in building envelope construction. Measurement of water vapour permeability, liquid water absorption, sorption isotherms, thermal conductivity, and air permeability were performed on three Canadian CLT specimens composed of Hem-Fir, Eastern Spruce-Pine-Fir, and Western Spruce-Pine-Fir and one European specimen composed of Spruce. The hygrothermal properties of CLT, considered in this study, appear to be similar to commonly used wood specimens reported in the literature. However, liquid water absorption coefficients of CLT were found to be generally lower than common wood species, possibly due to the presence of glue between the wood layers which limits the moisture movement across the specimen. On the other hand, the air permeability across the CLT specimens varied due to the glue discontinuity within the specimen which led some CLTs to be permeable, however all the European specimens were found to be impermeable. This study also critically analyzed the significance of equilibrium moisture content (EMC) of wood at high relative humidity, measured by means of a pressure plate apparatus and humidity chambers, on the moisture management performance of a wood-frame stucco wall, using the hygrothermal simulation tool hygIRC-2D. The simulation results indicate that the prediction of the moisture response of a wood-frame stucco wall assembly depends significantly on the method adopted to derive the EMC of wood at high RH.

Effects of thermal and mechanical fatigue on the flexural strength of G40-600/PMR-15 cross-ply laminates

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

Roberts, G.D.; Ho, B.Ping Hsiao; Wallace, J.F.

1993-02-01

The effects of thermal and mechanical fatigue on the flexural strength of G40-600/PMR-15 cross-ply laminates with ply orientation of (0(2),90(2))2S and (90(2),0(2))2S are examined. The relative importance of shear and tensile stresses is examined by varying the span-to-depth ratios of flexural test specimens from 8 to 45. Acoustic emission signals are measured during the flexural tests in order to monitor the initiation and growth of damage. Optical microscopy is used to examine specimens for resin cracking, delamination, and fiber breaks after testing. Transverse matrix cracks and delaminations occur in all specimens, regardless of ply orientation, span-to-depth ratio, or previous exposuremore » of specimens to thermal and mechanical fatigue. A small amount of fiber tensile fracture occurs in the outer 0 deg ply of specimens with high span-to-depth ratios. Because of the complex failure modes, the flexural test results represent the apparent strengths rather than the true flexural or shear strengths for these cross-ply laminates. Thermal cycling of specimens prior to flexural testing does not reduce the apparent flexural strength or change the mode of failure. However, fewer acoustic events are recorded at all strains during flexural testing of specimens exposed to prior thermal cycling. High temperature thermal cycling (32 to 260 C, 100 cycles) causes a greater reduction in acoustic events than low temperature thermal cycling (-85 to +85 C, 500 cycles). Mechanical cycling (0 to 50 percent of the flexural strength, 100 cycles) has a similar effect, except that acoustic events are reduced only at strains less than the maximum strain applied during flexural fatigue.« less

Effects of thermal and mechanical fatigue on the flexural strength of G40-600/PMR-15 cross-ply laminates

NASA Technical Reports Server (NTRS)

Roberts, Gary D.; Ho, Barry Ping Hsiao; Wallace, John F.

1993-01-01

The effects of thermal and mechanical fatigue on the flexural strength of G40-600/PMR-15 cross-ply laminates with ply orientation of (0(2),90(2))2S and (90(2),0(2))2S are examined. The relative importance of shear and tensile stresses is examined by varying the span-to-depth ratios of flexural test specimens from 8 to 45. Acoustic emission signals are measured during the flexural tests in order to monitor the initiation and growth of damage. Optical microscopy is used to examine specimens for resin cracking, delamination, and fiber breaks after testing. Transverse matrix cracks and delaminations occur in all specimens, regardless of ply orientation, span-to-depth ratio, or previous exposure of specimens to thermal and mechanical fatigue. A small amount of fiber tensile fracture occurs in the outer 0 deg ply of specimens with high span-to-depth ratios. Because of the complex failure modes, the flexural test results represent the 'apparent' strengths rather than the true flexural or shear strengths for these cross-ply laminates. Thermal cycling of specimens prior to flexural testing does not reduce the apparent flexural strength or change the mode of failure. However, fewer acoustic events are recorded at all strains during flexural testing of specimens exposed to prior thermal cycling. High temperature thermal cycling (32 to 260 C, 100 cycles) causes a greater reduction in acoustic events than low temperature thermal cycling (-85 to +85 C, 500 cycles). Mechanical cycling (0 to 50 percent of the flexural strength, 100 cycles) has a similar effect, except that acoustic events are reduced only at strains less than the maximum strain applied during flexural fatigue.

Effects of Intracranial Trochlear Neurectomy on the Structure of the Primate Superior Oblique Muscle

PubMed Central

Poukens, Vadims; Ying, Howard; Shan, Xiaoyan; Tian, Jing; Zee, David S.

2010-01-01

Purpose. Although cyclovertical strabismus in humans is frequently attributed to superior oblique (SO) palsy, anatomic effects of SO denervation have not been studied. Magnetic resonance imaging (MRI) and orbital histology was used to study the effects of acute trochlear (CN4) denervation on the monkey SO. Methods. Five juvenile macaque monkeys were perfused with formalin for 5 weeks: 15 months after unilateral or bilateral 10-mm intracranial trochlear neurectomy. Denervated and fellow orbits were imaged by MRI, embedded whole in paraffin, serially sectioned at 10-μm thickness, and stained with Masson trichrome. Whole muscle and individual fiber cross sections were quantified in SO muscles throughout the orbit and traced larger fibers in one specimen where they were present. Results. MRI demonstrated marked reduction in midorbital cross section in denervated SO muscles, with anterior shift of SO mass preserving overall volume. Muscle fibers exhibited variable atrophy along their lengths. Denervated orbital layer (OL) fiber cross sections were slightly but significantly reduced from control at most anteroposterior locations, but this reduction was much more profound in global layer (GL) fibers. Intraorbital and intramuscular CN4 were uniformly fibrotic. In one animal, there were scattered clusters of markedly hypertrophic GL fibers that exhibited only sparse myomyous junctions only anteriorly. Conclusions. CN4 denervation produces predominantly SO GL atrophy with relative OL sparing. Overall midorbital SO atrophy was evident by MRI as early as 5 weeks after denervation, as denervated SO volume shifted anteriorly. Occasional GL fiber hypertrophy suggests that at least some SO fibers extend essentially the full muscle length after trochlear neurectomy. PMID:20164458

Substantial vertebral body osteophytes protect against severe vertebral fractures in compression

PubMed Central

Aubin, Carl-Éric; Chaumoître, Kathia; Mac-Thiong, Jean-Marc; Ménard, Anne-Laure; Petit, Yvan; Garo, Anaïs; Arnoux, Pierre-Jean

2017-01-01

Recent findings suggest that vertebral osteophytes increase the resistance of the spine to compression. However, the role of vertebral osteophytes on the biomechanical response of the spine under fast dynamic compression, up to failure, is unclear. Seventeen human spine specimens composed of three vertebrae (from T5-T7 to T11-L1) and their surrounding soft tissues were harvested from nine cadavers, aged 77 to 92 years. Specimens were imaged using quantitative computer tomography (QCT) for medical observation, classification of the intervertebral disc degeneration (Thomson grade) and measurement of the vertebral trabecular density (VTD), height and cross-sectional area. Specimens were divided into two groups (with (n = 9) or without (n = 8) substantial vertebral body osteophytes) and compressed axially at a dynamic displacement rate of 1 m/s, up to failure. Normalized force-displacement curves, videos and QCT images allowed characterizing failure parameters (force, displacement and energy at failure) and fracture patterns. Results were analyzed using chi-squared tests for sampling distributions and linear regression for correlations between VTD and failure parameters. Specimens with substantial vertebral body osteophytes present higher stiffness (2.7 times on average) and force at failure (1.8 times on average) than other segments. The presence of osteophytes significantly influences the location, pattern and type of fracture. VTD was a good predictor of the dynamic force and energy at failure for specimens without substantial osteophytes. This study also showed that vertebral body osteophytes provide a protective mechanism to the underlying vertebra against severe compression fractures. PMID:29065144

Friction behavior and other material properties of nickel-titanium and titanium-molybdenum archwires following electrochemical surface refinement.

PubMed

Meier, Miriam Julia; Bourauel, Christoph; Roehlike, Jan; Reimann, Susanne; Keilig, Ludger; Braumann, Bert

2014-07-01

The aim of this work was to investigate whether electrochemical surface treatment of nickel-titanium (NiTi) and titanium-molybdenum (TiMo) archwires (OptoTherm and BetaTitan; Ortho-Dent Specials, Kisdorf, Germany) reduces friction inside the bracket-archwire complex. We also evaluated further material properties and compared these to untreated wires. The material properties of the surface-treated wires (Optotherm/LoFrix and BetaTitan/LoFrix) were compared to untreated wires made by the same manufacturer (see above) and by another manufacturer (Neo Sentalloy; GAC, Bohemia, NY, USA). We carried out a three-point bending test, leveling test, and friction test using an orthodontic measurement and simulation system (OMSS). In addition, a pure bending test was conducted at a special test station, and scanning electron micrographs were obtained to analyze the various wire types for surface characteristics. Finally, edge beveling and cross-sectional dimensions were assessed. Force losses due to friction were reduced by 10 percentage points (from 36 to 26%) in the NiTi and by 12 percentage points (from 59 to 47%) in the TiMo wire specimens. Most of the other material properties exhibited no significant changes after surface treatment. While the three-point bending tests revealed mildly reduced force levels in the TiMo specimens due to diameter losses of roughly 2%, these force levels remained almost unchanged in the NiTi specimens. Compared to untreated NiTi and TiMo archwire specimens, the surface-treated specimens demonstrated reductions in friction loss by 10 and 12 percentage points, respectively.

Dialysis Amyloid Deposition in the Aortic Valve and Its Association with Aortic Stenosis.

PubMed

Kurita, Noriaki; Fujii, Akiko; Kotera, Nagaaki; Tanaka, Mototsugu; Tanaka, Shinji; Miyairi, Takeshi; Sugimoto, Tokuichiro; Mori, Masaya; Fukuhara, Shunichi; Mise, Naobumi

2015-01-01

The relationship between dialysis amyloid (DA) deposition in the aortic valve (AV) and aortic stenosis (AS) is unknown. This was a cross-sectional study. AV specimens of dialysis patients (median vintage: 8.8 years) consecutively collected from cardiac surgeries (n = 56) or autopsies (n = 13) were examined by a board-certified pathologist blinded to clinical data. DAs were considered to be present if deposits were stained both by Congo red with apple-green birefringence under polarized light and by anti-β2-microblobulin antibody. Degree of deposition was graded as follows: Amyloid (-), no deposit; Amyloid (1+), occasional small deposits; Amyloid (2+), multiple small to large deposits or a single large deposit. Calcification was defined as a calcified deposit with a diameter >1 mm in the specimen. Severe AS (sAS) was defined as a mean gradient >50 mm Hg by echocardiogram. We examined the proportion of DAs and the association between DAs and the sAS. DAs were present in 71% (n = 49) of specimens and primarily co-localized with calcification. Non-dialysis related amyloid was found in one specimen. After excluding this specimen, sAS was associated with ‘Amyloid (1+) and Calcification >1 mm' and ‘Amyloid (2+) and Calcification >1 mm' (vs. ‘Amyloid (-) and Calcification ≤1 mm', odds ratios (ORs): 13.5 and 34.2, respectively). Furthermore, after adjustment for covariates, sAS was found to be associated with ‘Amyloid (2+) and Calcification >1 mm' (OR: 24.3). DA deposition in the AV was prevalent among dialysis patients. DA deposition with accompanying calcification might contribute to the severity of AS.

Production of ultrafine grained aluminum by cyclic severe plastic deformation at ambient temperature

NASA Astrophysics Data System (ADS)

Bereczki, P.; Szombathelyi, V.; Krallics, G.

2014-08-01

In the present study the possibilities of grain refinement was investigated by applying large-scale of cyclic plastic deformation to aluminum at ambient temperature. The specimens are processed by multiaxial forging, which is one of the severe plastic deformation techniques. The aim of the experiments with the aluminum alloy 6082M was the determination of the equivalent stress and strain by multiaxial forging and the investigation of evolution of mechanical properties in relation with the accumulated deformation in the specimen. The mechanical properties of raw material was determined by plane strain compression test as well as by hardness measurements. The forming experiments were carried out on Gleeble 3800 physical simulator with MaxStrain System. The mechanical properties of the forged specimens were investigated by micro hardness measurements and tensile tests. A mechanical model, based on the principle of virtual velocities was developed to calculate the flow curves using the measured dimensional changes of the specimen and the measured force. With respect to the evolution of these curves, the cyclic growth of the flow stress can be observed at every characteristic points of the calculated flow curves. In accordance with this tendency, the evolution of the hardness along the middle cross section of the deformed volume has also a nonmonotonous characteristic and the magnitudes of these values are much smaller than by the specimen after plane strain compression test. This difference between the flow stresses respect to the monotonic and non-monotonic deformation can be also observed. The formed microstructure, after a 10-passes multiaxial forging process, consists of mainly equiaxial grains in the submicron grain scale.

21 CFR 862.1675 - Blood specimen collection device.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Blood specimen collection device. 862.1675 Section... Systems § 862.1675 Blood specimen collection device. (a) Identification. A blood specimen collection device is a device intended for medical purposes to collect and to handle blood specimens and to separate...

21 CFR 862.1675 - Blood specimen collection device.

Code of Federal Regulations, 2012 CFR

2012-04-01

... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Blood specimen collection device. 862.1675 Section... Systems § 862.1675 Blood specimen collection device. (a) Identification. A blood specimen collection device is a device intended for medical purposes to collect and to handle blood specimens and to separate...

21 CFR 862.1675 - Blood specimen collection device.

Code of Federal Regulations, 2014 CFR

2014-04-01

... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Blood specimen collection device. 862.1675 Section... Systems § 862.1675 Blood specimen collection device. (a) Identification. A blood specimen collection device is a device intended for medical purposes to collect and to handle blood specimens and to separate...

21 CFR 862.1675 - Blood specimen collection device.

Code of Federal Regulations, 2013 CFR

2013-04-01

... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Blood specimen collection device. 862.1675 Section... Systems § 862.1675 Blood specimen collection device. (a) Identification. A blood specimen collection device is a device intended for medical purposes to collect and to handle blood specimens and to separate...

21 CFR 862.1675 - Blood specimen collection device.

Code of Federal Regulations, 2011 CFR

2011-04-01

... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Blood specimen collection device. 862.1675 Section... Systems § 862.1675 Blood specimen collection device. (a) Identification. A blood specimen collection device is a device intended for medical purposes to collect and to handle blood specimens and to separate...

Matrix vesicles in the fibrous cap of atherosclerotic plaque: possible contribution to plaque rupture.

PubMed

Bobryshev, Y V; Killingsworth, M C; Lord, R S A; Grabs, A J

2008-10-01

Plaque rupture is the most common type of plaque complication and leads to acute ischaemic events such as myocardial infarction and stroke. Calcification has been suggested as a possible indicator of plaque instability. Although the role of matrix vesicles in the initial stages of arterial calcification has been recognized, no studies have yet been carried out to examine a possible role of matrix vesicles in plaque destabilization. Tissue specimens selected for the present study represented carotid specimens obtained from patients undergoing carotid endarterectomy. Serial frozen cross-sections of the tissue specimens were cut and mounted on glass slides. The thickness of the fibrous cap (FCT) in each advanced atherosclerotic lesion, containing a well developed lipid/necrotic core, was measured at its narrowest sites in sets of serial sections. According to established criteria, atherosclerotic plaque specimens were histologically subdivided into two groups: vulnerable plaques with thin fibrous caps (FCT <100 microm) and presumably stable plaques, in which fibrous caps were thicker than 100 microm. Twenty-four carotid plaques (12 vulnerable and 12 presumably stable plaques) were collected for the present analysis of matrix vesicles in fibrous caps. In order to provide a sufficient number of representative areas from each plaque, laser capture microdissection (LCM) was carried out. The quantification of matrix vesicles in ultrathin sections of vulnerable and stable plaques revealed that the numbers of matrix vesicles were significantly higher in fibrous caps of vulnerable plaques than those in stable plaques (8.908+0.544 versus 6.208+0.467 matrix vesicles per 1.92 microm2 standard area; P= 0.0002). Electron microscopy combined with X-ray elemental microanalysis showed that some matrix vesicles in atherosclerotic plaques were undergoing calcification and were characterized by a high content of calcium and phosphorus. The percentage of calcified matrix vesicles/microcalcifications was significantly higher in fibrous caps in vulnerable plaques compared with that in stable plaques (6.705+/-0.436 versus 5.322+/-0494; P= 0.0474). The findings reinforce a view that the texture of the extracellular matrix in the thinning fibrous cap of atherosclerotic plaque is altered and this might contribute to plaque destabilization.

Design Guideline for New Generation of High-Temperature Guarded Hot Plate

NASA Astrophysics Data System (ADS)

Wu, J.; Hameury, J.; Failleau, G.; Blahut, A.; Vachova, T.; Strnad, R.; Krause, M.; Rafeld, E.; Hammerschmidt, U.

2018-02-01

This paper complements the existing measurement standards and literature for high-temperature guarded hot plates (HTGHPs) by addressing specific issues relating to thermal conductivity measurement of technical insulation at high temperatures. The examples given are focused on the designs of HTGHPs for measuring thin thermal insulation. The sensitivity studies have been carried out on major influencing factors that affect the thermal conductivity measurements using HTGHPs, e.g., the uncertainty of temperature measurements, plate flatness and center-guard gap design and imbalance. A new configuration of center-guard gap with triangular shape cross section has been optimized to obtain the same thermal resistance as a 2 mm wide gap with rectangular shape cross section that has been used in the HTGHPs at NPL and LNE. Recommendations have been made on the selections of heater plate materials, high-temperature high-emissivity coatings and miniature temperature sensors. For the first time, thermal stress analysis method has been applied to the field of HTGHPs, in order to estimate the effect of differential thermal expansion on the flatness of thin rigid specimens during thermal conductivity tests in a GHP.

Determining physiological cross-sectional area of extensor carpi radialis longus and brevis as a whole and by regions using 3D computer muscle models created from digitized fiber bundle data.

PubMed

Ravichandiran, Kajeandra; Ravichandiran, Mayoorendra; Oliver, Michele L; Singh, Karan S; McKee, Nancy H; Agur, Anne M R

2009-09-01

Architectural parameters and physiological cross-sectional area (PCSA) are important determinants of muscle function. Extensor carpi radialis longus (ECRL) and brevis (ECRB) are used in muscle transfers; however, their regional architectural differences have not been investigated. The aim of this study is to develop computational algorithms to quantify and compare architectural parameters (fiber bundle length, pennation angle, and volume) and PCSA of ECRL and ECRB. Fiber bundles distributed throughout the volume of ECRL (75+/-20) and ECRB (110+/-30) were digitized in eight formalin embalmed cadaveric specimens. The digitized data was reconstructed in Autodesk Maya with computational algorithms implemented in Python. The mean PCSA and fiber bundle length were significantly different between ECRL and ECRB (p < or = 0.05). Superficial ECRL had significantly longer fiber bundle length than the deep region, whereas the PCSA of superficial ECRB was significantly larger than the deep region. The regional quantification of architectural parameters and PCSA provides a framework for the exploration of partial tendon transfers of ECRL and ECRB.

3D printed pathological sectioning boxes to facilitate radiological-pathological correlation in hepatectomy cases.

PubMed

Trout, Andrew T; Batie, Matthew R; Gupta, Anita; Sheridan, Rachel M; Tiao, Gregory M; Towbin, Alexander J

2017-11-01

Radiogenomics promises to identify tumour imaging features indicative of genomic or proteomic aberrations that can be therapeutically targeted allowing precision personalised therapy. An accurate radiological-pathological correlation is critical to the process of radiogenomic characterisation of tumours. An accurate correlation, however, is difficult to achieve with current pathological sectioning techniques which result in sectioning in non-standard planes. The purpose of this work is to present a technique to standardise hepatic sectioning to facilitateradiological-pathological correlation. We describe a process in which three-dimensional (3D)-printed specimen boxes based on preoperative cross-sectional imaging (CT and MRI) can be used to facilitate pathological sectioning in standard planes immediately on hepatic resection enabling improved tumour mapping. We have applied this process in 13 patients undergoing hepatectomy and have observed close correlation between imaging and gross pathology in patients with both unifocal and multifocal tumours. © Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2017. All rights reserved. No commercial use is permitted unless otherwise expressly granted.

Effect of accelerated aging on the cross-link density of medical grade silicones.

PubMed

Mahomed, Aziza; Pormehr, Negin Bagheri

2016-11-25

Four specimens of Nagor silicone of different hardness (soft, medium and hard) were swollen, until they reached equilibrium (i.e. constant mass) in five liquids at 25°C, before and after accelerated aging. For the specimens swollen before accelerated aging, the greatest swelling was obtained in methyl cyclohexane, while for the specimens swollen after accelerated aging, the greatest swelling was obtained in cyclohexane. The cross-link density, υ, was also calculated from the swelling measurements for all the specimens, before and after accelerated aging, using the Flory-Rehner equation. The softer silicones, which swelled the most, had lower υ values than harder silicones. The amount of swelling (measured in terms of ϕ) and υ varied significantly (p<0.05) in some cases, between the different silicone hardness and between different liquids. Furthermore, the cross-link density, υ, significantly (p<0.05) increased after accelerated aging in most liquids.Note: ϕ is defined as the volume fraction of polymer in its equilibrium swollen state. A probability value of statistical significance of 0.05 or 5% was selected, hence if a p value of less than 0.05 was obtained, the null hypothesis was rejected (i.e. significant if p<0.05).

The influence of muscle pennation angle and cross-sectional area on contact forces in the ankle joint

PubMed Central

Sopher, Ran S; Amis, Andrew A; Davies, D Ceri; Jeffers, Jonathan RT

2016-01-01

Data about a muscle’s fibre pennation angle and physiological cross-sectional area are used in musculoskeletal modelling to estimate muscle forces, which are used to calculate joint contact forces. For the leg, muscle architecture data are derived from studies that measured pennation angle at the muscle surface, but not deep within it. Musculoskeletal models developed to estimate joint contact loads have usually been based on the mean values of pennation angle and physiological cross-sectional area. Therefore, the first aim of this study was to investigate differences between superficial and deep pennation angles within each muscle acting over the ankle and predict how differences may influence muscle forces calculated in musculoskeletal modelling. The second aim was to investigate how inter-subject variability in physiological cross-sectional area and pennation angle affects calculated ankle contact forces. Eight cadaveric legs were dissected to excise the muscles acting over the ankle. The mean surface and deep pennation angles, fibre length and physiological cross-sectional area were measured. Cluster analysis was applied to group the muscles according to their architectural characteristics. A previously validated OpenSim model was used to estimate ankle muscle forces and contact loads using architecture data from all eight limbs. The mean surface pennation angle for soleus was significantly greater (54%) than the mean deep pennation angle. Cluster analysis revealed three groups of muscles with similar architecture and function: deep plantarflexors and peroneals, superficial plantarflexors and dorsiflexors. Peak ankle contact force was predicted to occur before toe-off, with magnitude greater than five times bodyweight. Inter-specimen variability in contact force was smallest at peak force. These findings will help improve the development of experimental and computational musculoskeletal models by providing data to estimate force based on both surface and deep pennation angles. Inter-subject variability in muscle architecture affected ankle muscle and contact loads only slightly. The link between muscle architecture and function contributes to the understanding of the relationship between muscle structure and function. PMID:29805194

Evaluation of tensile bond strength of heat cure and autopolymerizing silicone-based resilient denture liners before and after thermocycling.

PubMed

Madan, Nishtha; Datta, Kusum

2012-01-01

To assess the effect of simulated mouth conditions reproduced with thermocycling on the tensile bond strength of two silicone based resilient denture liners with acrylic resin bases. Two silicone-based soft denture liners (Mollosil - Chairside autopolymerization and Molloplast B - Heat polymerization) were tested. For each liner, 30 specimens with a cross-sectional area of 10 Χ 10 mm and thickness 3 mm were processed between two acrylic blocks (Trevalon). Specimens were divided into a control group that was stored for 24 hours in water at 37°C and a test group that was thermocycled (2500 cycles) between baths of 5° and 55°C. Tensile bond strength (kg/cm²) was determined in a universal testing machine using crosshead speed of 5 mm/min. The student t-test was used to determine the significance of the difference in bond strength between the two liners. The mean tensile bond strength for control and thermocycled specimens of the two liners were: Mollosil (6.82 kg/cm² and 8.41 kg/cm²) and Molloplast-B (16.30 kg/cm² and 13.67 kg/cm²), respectively. Comparison of bond strength of control specimens with thermocycled specimens of the liners indicated a significant difference for both Mollosil (P=0.045) and Molloplast-B (P=0.027). Comparison between control specimens of both liners and thermocycled specimens of both liners indicated a highly significant difference (P<0.001). Heat polymerized resilient denture liner Molloplast-B had higher tensile bond strength than autopolymerizing liner Mollosil regardless of thermocycling. The bond strength of Mollosil increased after thermocycling while that of Molloplast-B decreased after thermocycling. Although heat-polymerized denture liners require more processing time than autopolymerizing liners, but they display much better adhesion properties to denture base resin and should thus be preferred when soft liner has to be used for a longer duration of time.

Characterization of corneal pannus removed from patients with total limbal stem cell deficiency.

PubMed

Espana, Edgar M; Di Pascuale, Mario A; He, Hua; Kawakita, Tetsuya; Raju, Vadrevu K; Liu, Chia-Yang; Tseng, Scheffer C G

2004-09-01

To determine the epithelial lineage of origin in corneal pannus tissue surgically removed from patients with total limbal stem cell (SC) deficiency. The lineage of origin of the entire conjunctivalized pannus removed from eight corneas with a diagnosis of total limbal SC deficiency was characterized by anti-keratin (K)-3 and anti-K19 monoclonal antibodies. The protein and mRNA of epithelial outgrowth from segments of five such pannus specimens were analyzed by Western blot and reverse transcription-polymerase chain reaction, respectively. Cross sections of all eight specimens showed a stratified epithelium with goblet cells expressing mucin (MUC)-5AC, and a stroma showing blood vessels and inflammatory cell infiltrates. Immunostaining showed full-thickness expression of K19 in the entire pannus of all eight specimens. Expression of K3 was negative in seven patients, but was sporadically positive in a patient with Stevens-Johnson syndrome. In culture, all five pannus specimens generated a compact, small epithelial cell outgrowth, and except for one, reached confluence in 2 to 3 weeks. The K3/K12 pair was expressed by extracts of cell outgrowth from the control limbal epithelial explant, but not in all five pannus specimens. A 60-kDa band of DeltaNp63 was expressed in the control specimen and in all five pannus specimens. Cell outgrowth expressed K3 transcript in three, but none showed K12 transcript. The resultant epithelial phenotype of the pannus tissue was not corneal, as evidenced by the negative staining to cornea-specific K12 mRNA and protein, but was conjunctival, as evidenced by the presence of goblet cells, the weak expression of K3, and the strong expression of K19. The abundant expression of DeltaNp63 in such conjunctiva-derived epithelium in eyes with total limbal SC deficiency raises doubts as to its validity as a limbal SC marker. Copyright Association for Research in Vision and Ophthalmology

Predicting fracture of mortar beams under three-point bending using non-extensive statistical modeling of electric emissions

NASA Astrophysics Data System (ADS)

Stergiopoulos, Ch.; Stavrakas, I.; Triantis, D.; Vallianatos, F.; Stonham, J.

2015-02-01

Weak electric signals termed as 'Pressure Stimulated Currents, PSC' are generated and detected while cement based materials are found under mechanical load, related to the creation of cracks and the consequent evolution of cracks' network in the bulk of the specimen. During the experiment a set of cement mortar beams of rectangular cross-section were subjected to Three-Point Bending (3PB). For each one of the specimens an abrupt mechanical load step was applied, increased from the low load level (Lo) to a high final value (Lh) , where Lh was different for each specimen and it was maintained constant for long time. The temporal behavior of the recorded PSC show that during the load increase a spike-like PSC emission was recorded and consequently a relaxation of the PSC, after reaching its final value, follows. The relaxation process of the PSC was studied using non-extensive statistical physics (NESP) based on Tsallis entropy equation. The behavior of the Tsallis q parameter was studied in relaxation PSCs in order to investigate its potential use as an index for monitoring the crack evolution process with a potential use in non-destructive laboratory testing of cement-based specimens of unknown internal damage level. The dependence of the q-parameter on the Lh (when Lh <0.8Lf), where Lf represents the 3PB strength of the specimen, shows an increase on the q value when the specimens are subjected to gradually higher bending loadings and reaches a maximum value close to 1.4 when the applied Lh becomes higher than 0.8Lf. While the applied Lh becomes higher than 0.9Lf the value of the q-parameter gradually decreases. This analysis of the experimental data manifests that the value of the entropic index q obtains a characteristic decrease while reaching the ultimate strength of the specimen, and thus could be used as a forerunner of the expected failure.

Self-aligning biaxial load frame

DOEpatents

Ward, M.B.; Epstein, J.S.; Lloyd, W.R.

1994-01-18

An self-aligning biaxial loading apparatus for use in testing the strength of specimens while maintaining a constant specimen centroid during the loading operation. The self-aligning biaxial loading apparatus consists of a load frame and two load assemblies for imparting two independent perpendicular forces upon a test specimen. The constant test specimen centroid is maintained by providing elements for linear motion of the load frame relative to a fixed cross head, and by alignment and linear motion elements of one load assembly relative to the load frame. 3 figures.

Effect of root canal sealer and artificial accelerated aging on fibreglass post bond strength to intraradicular dentin.

PubMed

Santana, Fernanda-Ribeiro; Soares, Carlos-José; Ferreira, Josemar-Martins; Valdivi, Andréa-Dolores-Correia-Miranda; Souza, João-Batista-de; Estrela, Carlos

2014-10-01

To evaluate the effect of root canal sealers (RCS) and specimen aging on the bond strength of fibre posts to bovine intraradicular dentin. 80 teeth were used according the groups - Sealapextm, Sealer 26®, AH Plus® and specimens aging - test with no aging and with aging. The canals prepared were filled using one of each RCS. The posts were cemented. Roots were cross-sectioned to obtain two slices of each third. Samples were submitted to push-out test. Failure mode was evaluated under a confocal microscope. The data were analysed by ANOVA, Tukey's, and Dunnet tests (α = 0.05). No significant difference was detected among RCS. Aged control presented higher bond strength than immediate control. The aging did not result significant difference. Adhesive cement-dentin failure was prevalent in all groups. RCS interfered negatively with bonding of fibreglass posts cemented with self-adhesive resin cement to intraradicular dentin. Key words:Fibreglass post, bond strength, root dentin, endodontic sealer, aging.

Development of chloride-induced corrosion in pre-cracked RC beams under sustained loading: Effect of load-induced cracks, concrete cover, and exposure conditions

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

Yu, Linwen; Université de Sherbrooke, Quebec; François, Raoul, E-mail: raoul.francois@insa-toulouse.fr

2015-01-15

This paper deals with corrosion initiation and propagation in pre-cracked reinforced concrete beams under sustained loading during exposure to a chloride environment. Specimen beams that were cast in 2010 were compared to specimens cast in 1984. The only differences between the two sets of beams were the casting direction in relation to tensile reinforcement and the exposure conditions in the salt-fog chamber. The cracking maps, corrosion maps, chloride profiles, and cross-sectional loss of one group of two beams cast in 2010 were studied and their calculated corrosion rates were compared to that of beams cast in 1984 in order tomore » investigate the factors influencing the natural corrosion process. Experimental results show that, after rapid initiation of corrosion at the crack tip, the corrosion process practically halted and the time elapsing before corrosion resumed depended on the exposure conditions and cover depth.« less

Novel Bonding Technology for Hermetically Sealed Silicon Micropackage

NASA Astrophysics Data System (ADS)

Lee, Duck-Jung; Ju, Byeong-Kwon; Choi, Woo-Beom; Jeong, Jee-Won; Lee, Yun-Hi; Jang, Jin; Lee, Kwang-Bae; Oh, Myung-Hwan

1999-01-01

We performed glass-to-silicon bonding and fabricated a hermetically sealed silicon wafer using silicon direct bonding followed by anodic bonding (SDAB). The hydrophilized glass and silicon wafers in solution were dried and initially bonded in atmosphere as in the silicon direct bonding (SDB) process, but annealing at high temperature was not performed. Anodic bonding was subsequently carried out for the initially bonded specimens. Then the wafer pairs bonded by the SDAB method were different from those bonded by the anodic bonding process only. The effects of the bonding process on the bonded area and tensile strength were investigated as functions of bonding temperature and voltage. Using scanning electron microscopy (SEM), the cross-sectional view of the bonded interface region was observed. In order to investigate the migration of the sodium ions in the bonding process, the concentration of the bonded glass was compared with that of standard glass. The specimen bonded using the SDAB process had higher efficiency than that using the anodic bonding process only.

Elevated Temperature Corrosion Studies of AlCrN and TiAlN Coatings by PAPVD on T91 Boiler Steel

NASA Astrophysics Data System (ADS)

Goyal, Lucky; Chawla, Vikas; Hundal, Jasbir Singh

2017-11-01

The present investigation discusses the hot corrosion behavior of AlCrN and TiAlN nano-coatings on T91 boiler steel by PAPVD process subjected to molten salt of Na2SO4-60%V2O5 at 900 °C for 50 cycles. Surface and cross-sectional studies were performed by AFM, SEM/EDS and XRD techniques to understand the corrosion kinetics and mechanism. T91 bare boiler steel as well as TiAlN-coated specimen has shown higher internal oxidation as well as weight gain. The better corrosion resistance of AlCrN-coated specimen has been observed by virtue of higher availability of Cr and Al in the oxide scale as well as adherent and dense coating. The betterment of AlCrN coating can be attributed to low internal oxidation as well as movement of Cr and Al toward oxide scale to form protective corrosion barriers.

Mechanical Behavior of a Hi-Nicalon(tm)/SiC Composite Having a Polycarbosilane Derived Matrix

NASA Technical Reports Server (NTRS)

Hurwitz, Frances I.; Calomino, Anthony M.; McCue, Terry R.

1999-01-01

Polymer infiltration of a rigidized preform, followed by pyrolysis to convert the polymer to a ceramic, potentially offers a lower cost alternative to CVD. It also offers more moderate temperature requirements than melt infiltration approaches, which should minimize potential fiber damage during processing. However, polymer infiltration and pyrolysis results in a more microcracked matrix. Preliminary mechanical property characterization, including elevated temperature (1204 C) tensile, 500 h stress rupture behavior and low cycle fatigue, was conducted on Hi-Nicalon (TM)/Si-C-(O) composites having a dual layer BN/SiC interface and a matrix derived by impregnation and pyrolysis of allylhydridopolycarbosilane (AHPCS). Microstructural evaluation of failure surfaces and of polished transverse and longitudinal cross sections of the failed specimens was used to identify predominant failure mechanisms. In stress rupture testing at 1093 C, the failure was interface dominated, while at 1204 C in both stress rupture and two hour hold/fatigue tests failure was matrix dominated, resulting in specimen delamination.

Indentation fracture assessment of residual stress in Si{sub 3}N{sub 4}

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

Wu, K.H.; Liu, K.C.; Sentella, M.

1996-12-31

The measurement of residual stress in Si{sub 3}N{sub 4} ceramics was examined using the indentation technique while a bar specimen with a square cross-section was loaded in tension, and an indentation was created by means of a Vicker`s indenter. The stress applied to the specimen ranged from 0 to 98.8 MPa. The crack length and the shape of the crack were measured by both optical and scanning electron microscopes. Results of the tests indicate that the indentation fracture method can be used to accurately determine the residual stress existing in the material as well as to predict the K{sub c}more » value of the material. The indentation load must be higher than a critical value in order to develop a well-defined penny-shaped crack. For the Si{sub 3}N{sub 4} this critical load is approximately 3 kg. A geometric constant is an important factor for the calculation of the residual stress.« less

Assessment of current adhesives in class I cavity: Nondestructive imaging using optical coherence tomography and microtensile bond strength.

PubMed

Makishi, Patricia; Thitthaweerat, Suppason; Sadr, Alireza; Shimada, Yasushi; Martins, Adriano Luis; Tagami, Junji; Giannini, Marcelo

2015-09-01

To evaluate the sealing ability and the microtensile bond strength (MTBS) of different adhesive systems bonded to dentin in class I cavities. Round tapered dentin cavities (3-mm diameter, 1.5-mm height) prepared in extracted human molars were restored using composite resin (Clearfil Majesty Posterior) with two-step etch-and-rinse adhesive system (Adper Single Bond 2: ASB2), two-step self-etch adhesive (Clearfil SE Bond: CSEB), all-in-one adhesives (G-Bond Plus: GBP; Tri-S Bond Plus: TSBP), or no adhesive (Control), or bonded using low-shrinkage composite with its proper adhesive (Filtek Silorane, Silorane Adhesive System: FSS). After 24-h water storage or 10,000 cycles of thermal stress, the specimens were immersed into a contrast agent. Two and three-dimensional images were obtained using optical coherence tomography (OCT). The mean percentage of high brightness (HB%) at the interfacial zone in cross-sectional images was calculated as an indicator of contrast agent or gap at the interface. The specimens were then sectioned into beams and the MTBS measured. The HB% (ASB2=TSBP=CSEBTSBP=GBP=FSS, ASB2>FSS) differed significantly among the adhesives. After aging, HB% increased for GBP and FSS specimens, and the MTBS decreased for FSS specimens (ANOVA, Tukey's post hoc, p<0.05). The HB% and MTBS were significantly and negatively correlated (p=0.002). Confocal laser scanning and scanning electron micrographs confirmed contrast agent infiltration within the gap. There was a significant correlation between sealing performance and bond strength of the adhesives in the whole cavity. After aging, the two-step systems showed equal or superior performance to the all-in-one and Silorane systems. Copyright © 2015 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.

Bonding durability of a self-etching primer system to normal and caries-affected dentin under hydrostatic pulpal pressure in vitro.

PubMed

Nakajima, Masatoshi; Hosaka, Keiichi; Yamauti, Monica; Foxton, Richard M; Tagami, Junji

2006-06-01

To evaluate the bonding durability of a self-etching primer system to normal and caries-affected dentin under hydrostatic pulpal pressure. 18 extracted human molars with occlusal caries were used. Their occlusal dentin surfaces were ground flat to expose normal and caries-affected dentin using #600 SiC paper under running water. Clearfil SE Bond was placed on the dentin surface including the caries-affected dentin according to the manufacturer's instructions and then the crowns were built up with resin composite (Clearfil AP-X) under either a pulpal pressure of 15 cm H2O or none (control). The bonded specimens were stored in 100% humidity for 1 day (control) or for 1 week and 1 month with hydrostatic pulpal pressure. After storage, the specimens were serially sectioned into 0.7 mm-thick slabs and trimmed to an hour-glass shape with a 1 mm2 cross-section, isolated by normal or caries-affected dentin, and then subjected to the micro-tensile bond test. Data were analyzed by two-way ANOVA and Tukey's test (P< 0.05). Hydrostatic pulpal pressure significantly reduced the bond strength to normal dentin after 1-month storage (P< 0.05), but did not affect the bond strength to caries-affected dentin.

Biomechanical in vitro - stability testing on human specimens of a locking plate system against conventional screw fixation of a proximal first metatarsal lateral displacement osteotomy.

PubMed

Arnold, Heino; Stukenborg-Colsman, Christina; Hurschler, Christof; Seehaus, Frank; Bobrowitsch, Evgenij; Waizy, Hazibullah

2012-01-01

The aim of this study was to examine resistance to angulation and displacement of the internal fixation of a proximal first metatarsal lateral displacement osteotomy, using a locking plate system compared with a conventional crossed screw fixation. Seven anatomical human specimens were tested. Each specimen was tested with a locking screw plate as well as a crossed cancellous srew fixation. The statistical analysis was performed by the Friedman test. The level of significance was p = 0.05. We found larger stability about all three axes of movement analyzed for the PLATE than the crossed screws osteosynthesis (CSO). The Friedman test showed statistical significance at a level of p = 0.05 for all groups and both translational and rotational movements. The results of our study confirm that the fixation of the lateral proximal first metatarsal displacement osteotomy with a locking plate fixation is a technically simple procedure of superior stability.

Biomechanical In Vitro - Stability Testing on Human Specimens of a Locking Plate System Against Conventional Screw Fixation of a Proximal First Metatarsal Lateral Displacement Osteotomy

PubMed Central

Arnold, Heino; Stukenborg-Colsman, Christina; Hurschler, Christof; Seehaus, Frank; Bobrowitsch, Evgenij; Waizy, Hazibullah

2012-01-01

Introduction: The aim of this study was to examine resistance to angulation and displacement of the internal fixation of a proximal first metatarsal lateral displacement osteotomy, using a locking plate system compared with a conventional crossed screw fixation. Materials and Methodology: Seven anatomical human specimens were tested. Each specimen was tested with a locking screw plate as well as a crossed cancellous srew fixation. The statistical analysis was performed by the Friedman test. The level of significance was p = 0.05. Results: We found larger stability about all three axes of movement analyzed for the PLATE than the crossed screws osteosynthesis (CSO). The Friedman test showed statistical significance at a level of p = 0.05 for all groups and both translational and rotational movements. Conclusion: The results of our study confirm that the fixation of the lateral proximal first metatarsal displacement osteotomy with a locking plate fixation is a technically simple procedure of superior stability. PMID:22675409

Cross-reactivity of Toxocariasis with Crude Antigen of Toxascaris leonina Larvae by ELISA.

PubMed

Jin, Yan; Shen, Chenghua; Huh, Sun; Choi, Min-Ho; Hong, Sung-Tae

2015-05-01

Roundworms of Toxocara canis and Toxascaris leonina are common gastrointestinal helminths of canids over the world. Humans are infected with T. canis larvae through ingestion of infective eggs in contaminated environments or larvae by consumption of raw or uncooked meat or livers. Recently, patients of clinically diagnosed toxocariasis are increasing and require correct diagnosis in Korea. The present study investigated serological cross-reactivity between crude antigens of T. canis (TCLA) and T. leonina (TLLA) larvae. We collected serum specimens from 177 toxocariasis patients who were clinically suspected in the Seoul National University Hospital and 115 healthy controls. An ELISA method for toxocariasis was used to evaluate diagnostic efficacy of TLLA for serodiagnosis of human toxocariasis. The IgG ELISA using TLLA gave 14 (14.3%) positives of 98 TCLA positive specimens among 177 suspected toxocariasis patients. Most of them showed high absorbances with TCLA. In conclusion, there is a partial cross reaction between serum specimens of toxocariasis and TLLA.

Mechanical properties of dissimilar metal joints composed of DP 980 steel and AA 7075-T6

DOE PAGES

Squires, Lile; Lim, Yong Chae; Miles, Michael; ...

2015-03-18

In this study, a solid state joining process, called friction bit joining, was used to spot weld aluminium alloy 7075-T6 to dual phase 980 steel. Lap shear failure loads for specimens without adhesive averaged ~10kN, while cross-tension specimens averaged 2·8 kN. Addition of adhesive with a thickness up to 500 μm provided a gain of ~50% to lap shear failure loads, while a much thinner layer of adhesive increased cross-tension failure loads by 20%. Microstructures of the welds were martensitic, but the hardness of the joining bit portion was greater than that of the DP 980, owing to its highermore » alloy content. Softening in the heat affected zone of a welded joint appeared to be relatively small, though it was enough to cause nugget pullout failures in some lap shear tension specimens. Finally, other failures in lap shear tension were interfacial, while all of the failures in cross-tension were interfacial.« less

Endothelin-1 Expression in Prostate Needle Biopsy Specimens Correlated With Aggressiveness of Prostatic Cancer

PubMed Central

Asgari, Mojgan; Eftekhar, Elham; Abolhasani, Maryam; Shahrokh, Hossein

2017-01-01

Background & Objective: As the prostate adenocarcinoma is one of the most common malignant tumors in males, looking for a marker to effectively predict aggressiveness and metastatic potential in an apparently localized cancer in initial needle biopsy specimens can help the clinicians to make more appropriate decision for treatment, planning, and choosing appropriate targeted therapy. The present study assessed the value of Endothelin-1 expression to predict prognosis of prostatic cancer Methods: In a cross sectional study, 83 patients who underwent radical prostatectomy in Hasheminejad Kidney Center in 2008 through 2012 were assigned to two groups including 43 with and 40 without extra-prostatic extension (EPE). Endothelin-1 staining was performed on Paraffin Embedded blocks of preoperative needle biopsies. Results: The expression of Endothelin-1 increased in 72% of patients in the group with EPE (P<0.001). The group with Endothelin-1 positivity showed higher serum level of prostate specific antigen (PSA) (p = 0.039). Endothelin-1 expression was positive in 67% of patients with perineurial invasion (P<0.001). Adjusting the baseline variables of PSA and PN in a multivariable logistic regression model, the Endothelin-1 positivity could effectively predict EPE in patients with prostatic cancer (OR: 5.46, p = 0.010). Conclusion: Correlation of Endothelin-1 expression in needle biopsy specimens in expected with extra-prostatic extension of tumor in radical prostatectomy specimens, perineurial invasion and serum PSA level at the time of diagnosis. PMID:29515640

Direct immunofluorescence assay compared to cell culture for the diagnosis of mucocutaneous herpes simplex virus infections in children.

PubMed

Caviness, A Chantal; Oelze, Lindsay L; Saz, Ulas E; Greer, Jewel M; Demmler-Harrison, Gail J

2010-09-01

Direct immunofluorescence assay (DFA) is commonly used for the rapid identification of herpes simplex virus (HSV) infection in mucocutaneous lesions, yet little is known about its diagnostic accuracy. To determine the diagnostic yield and accuracy of HSV DFA for the diagnosis of mucocutaneous HSV infection in pediatric patients. Retrospective cross-sectional study of all patients who underwent HSV DFA testing by the Texas Children's Hospital Diagnostic Virology between January 1, 1995 and December 31, 2005. HSV DFA sensitivity, specificity, positive likelihood ratio (LRs), and negative LRs were estimated using viral culture as the reference standard. 659 specimens were submitted for HSV DFA with concurrent viral cultures. Viral cultures were positive for HSV type 1 in 158 (24%) and HSV type 2 in 2 (0.3%). There were 433 different patients with a median age of 8.6 years. Types of lesions were as follows: 50% ulcerative, 26% vesicular, 8% erythema or purpura, 5% pustular, and 11% missing. Of the 659 specimens submitted for HSV DFA, 160 (24%) were inconclusive due to inadequate cells. Of the 499 adequate specimens, overall HSV DFA test accuracy was: sensitivity 61%, specificity 99%, LR positive 40, and LR negative 0.39. A quarter of specimens submitted for HSV DFA testing are not adequate for DFA testing. When HSV DFA can be performed, it is specific, but not sensitive, for the identification of mucocutaneous HSV infection in children. Copyright (c) 2010 Elsevier B.V. All rights reserved.

Bonding characteristics of self-etching adhesives to intact versus prepared enamel.

PubMed

Perdigão, Jorge; Geraldeli, Saulo

2003-01-01

This study tested the null hypothesis that the preparation of the enamel surface would not affect the enamel microtensile bond strengths of self-etching adhesive materials. Ten bovine incisors were trimmed with a diamond saw to obtain a squared enamel surface with an area of 8 x 8 mm. The specimens were randomly assigned to five adhesives: (1) ABF (Kuraray), an experimental two-bottle self-etching adhesive; (2) Clearfil SE Bond (Kuraray), a two-bottle self-etching adhesive; (3) One-Up Bond F (Tokuyama), an all-in-one adhesive; (4) Prompt L-Pop (3M ESPE), an all-in-one adhesive; and (5) Single Bond (3M ESPE), a two-bottle total-etch adhesive used as positive control. For each specimen, one half was roughened with a diamond bur for 5 seconds under water spray, whereas the other half was left unprepared. The adhesives were applied as per manufacturers' directions. A universal hybrid composite resin (Filtek Z250, 3M ESPE) was inserted in three layers of 1.5 mm each and light-cured. Specimens were sectioned in X and Y directions to obtain bonded sticks with a cross-sectional area of 0.8 +/- 0.2 mm2. Sticks were tested in tension in an Instron at a cross-speed of 1 mm per minute. Statistical analysis was carried out with two-way analysis of variance and Duncan's test at p < .05. Ten extra specimens were processed for observation under a field-emission scanning electron microscope. Single Bond, the total-etch adhesive, resulted in statistically higher microtensile bond strength than any of the other adhesives regardless of the enamel preparation (unprepared = 31.5 MPa; prepared = 34.9 MPa, not statistically different at p < .05). All the self-etching adhesives resulted in higher microtensile bond strength when enamel was roughened than when enamel was left unprepared. However, for ABF and for Clearfil SE Bond this difference was not statistically significant at p > .05. When applied to ground enamel, mean bond strengths of Prompt L-Pop were not statistically different from those of Clearfil SE Bond and ABF. One-Up Bond F did not bond to unprepared enamel. Commercial self-etching adhesives performed better on prepared enamel than on unprepared enamel. The field-emission scanning electron microscope revealed a deep interprismatic etching pattern for the total-etch adhesive, whereas the self-etching systems resulted in an etching pattern ranging from absent to moderate.

Testing system for ferromagnetic shape memory microactuators.

PubMed

Ganor, Y; Shilo, D; Messier, J; Shield, T W; James, R D

2007-07-01

Ferromagnetic shape memory alloys are a class of smart materials that exhibit a unique combination of large strains and fast response when exposed to magnetic field. Accordingly, these materials have significant potential in motion generation applications such as microactuators and sensors. This article presents a novel experimental system that measures the dynamic magnetomechanical behavior of microscale ferromagnetic shape memory specimens. The system is comprised of an alternating magnetic field generator (AMFG) and a mechanical loading and sensing system. The AMFG generates a dynamic magnetic field that periodically alternates between two orthogonal directions to facilitate martensitic variant switching and to remotely achieve a full magnetic actuation cycle, without the need of mechanical resetting mechanisms. Moreover, the AMFG is designed to produce a magnetic field that inhibits 180 degrees magnetization domain switching, which causes energy loss without strain generation. The mechanical loading and sensing system maintains a constant mechanical load on the measured specimen by means of a cantilever beam, while the displacement is optically monitored with a resolution of approximately 0.1 microm. Preliminary measurements using Ni(2)MnGa single crystal specimens, with a cross section of 100x100 microm(2), verified their large actuation strains and established their potential to become a material of great importance in microactuation technology.

Evaluation of GeneXpert MTB/RIF for detecting Mycobacterium tuberculosis in a hospital in China.

PubMed

Tang, Tingyu; Liu, Fang; Lu, Xiaoling; Huang, Qingdong

2017-04-01

Objective To evaluate the performance of GeneXpert MTB/RIF in diagnosing pulmonary tuberculosis (TB) in China. Methods This cross-sectional study included sputum specimens of 240 suspected TB cases. Specimens were examined by light microscopy for the presence of acid-fast bacilli, which were cultured by the BACTEC MGIT 960 (M960) system and detected by the GeneXpert MTB/RIF assay. The positive rate, sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and average turnaround time of methods were evaluated. Results The positive rate was 36.6% (87/238) for the GeneXpert MTB/RIF assay and 34.0% (81/238) by M960 culture, with no significant difference between methods (χ 2  = 0.33, p > 0.05). According to culture results, sensitivity of the GeneXpert MTB/RIF assay was 84.0% (68/81), specificity was 87.8% (129/147), the PPV was 78.2% (68/87), and the NPV was 87.2% (129/148). The agreement for results between Gene Xpert MTB/RIF and the M960 system was 82.8% and the Kappa value was 0.73. Conclusion The GeneXpert MTB/RIF assay is a simple, rapid, and accurate test for detecting Mycobacterium tuberculosis in sputum specimens.

A Clinicopathological Study of Odontogenic Cysts and Tumors in Hamadan, Iran

PubMed Central

Baghaei, Fahimeh; Zargaran, Massoumeh; Najmi, Hamidreza; Moghimbeigi, Abbas

2014-01-01

Statement of the Problem: Odontogenic cysts and tumors are the most frequent osseous destructive lesions of the jaws; however, there is little information regarding the relative frequency of these lesions among the Iranian population. Purpose: The purpose of this study was to determine the distribution of clinically and histologically- diagnosed odontogenic cysts and tumors during a period of 13 years in Hamadan, and also its correlation with age, gender, and the site of the lesion. Materials and Method: A descriptive cross-sectional study was performed on 413 oral and maxillofacial specimens during 1996 to 2008.The age and the gender of patients, as well as the site of lesion were recorded. The data were analyzed using SPSS software. Results: Totally, 70 specimens were recorded as odontogenic cysts and 11 specimens were diagnosed as odontogenic tumors. The most frequent odontogenic cysts were dentigerous cysts (27.2%), followed by radicular cysts (18.6%) and odontogenic keratocysts (18.6%). In addition, cysts were more frequent in male than female individuals. Ameloblastoma was the most frequent odontogenic tumor (64%). Conclusion: Odontogenic cysts were in correlation with age, gender and location. These results showed that dentigerous cyst and odontogenic keratocyst were more frequent than other studies. More investigations should be performed to determine the frequency of odontogenic tumors in Iran. PMID:25469355

A clinicopathological study of odontogenic cysts and tumors in hamadan, iran.

PubMed

Baghaei, Fahimeh; Zargaran, Massoumeh; Najmi, Hamidreza; Moghimbeigi, Abbas

2014-12-01

Odontogenic cysts and tumors are the most frequent osseous destructive lesions of the jaws; however, there is little information regarding the relative frequency of these lesions among the Iranian population. The purpose of this study was to determine the distribution of clinically and histologically- diagnosed odontogenic cysts and tumors during a period of 13 years in Hamadan, and also its correlation with age, gender, and the site of the lesion. A descriptive cross-sectional study was performed on 413 oral and maxillofacial specimens during 1996 to 2008.The age and the gender of patients, as well as the site of lesion were recorded. The data were analyzed using SPSS software. Totally, 70 specimens were recorded as odontogenic cysts and 11 specimens were diagnosed as odontogenic tumors. The most frequent odontogenic cysts were dentigerous cysts (27.2%), followed by radicular cysts (18.6%) and odontogenic keratocysts (18.6%). In addition, cysts were more frequent in male than female individuals. Ameloblastoma was the most frequent odontogenic tumor (64%). Odontogenic cysts were in correlation with age, gender and location. These results showed that dentigerous cyst and odontogenic keratocyst were more frequent than other studies. More investigations should be performed to determine the frequency of odontogenic tumors in Iran.

Microstructure and mechanical properties of friction stir welded and laser welded high entropy alloy CrMnFeCoNi

NASA Astrophysics Data System (ADS)

Jo, Min-Gu; Kim, Han-Jin; Kang, Minjung; Madakashira, Phaniraj P.; Park, Eun Soo; Suh, Jin-Yoo; Kim, Dong-Ik; Hong, Sung-Tae; Han, Heung Nam

2018-01-01

The high entropy alloy CrMnFeCoNi has been shown to have promising structural properties. For a new alloy to be used in a structural application it should be weldable. In the present study, friction stir welding (FSW) and laser welding (LW) techniques were used to butt weld thin plates of CrMnFeCoNi. The microstructure, chemical homogeneity and mechanical behavior of the welds were characterized and compared with the base metal. The tensile stress-strain behavior of the welded specimens were reasonable when compared with that of the base metal. FSW refined the grain size in the weld region by a factor of ˜14 when compared with the base metal. High-angle annular dark field transmission electron microscopy in combination with energy dispersive X-ray spectroscopy showed chemical inhomogeneity between dendritic and interdendritic regions in the fusion zone of LW. Large fluctuations in composition (up to 15 at%) did not change the crystal structure in the fusion zone. Hardness measurements were carried out in the weld cross section and discussed in view of the grain size, low angle grain boundaries and twin boundaries in FSW specimens and the dendritic microstructure in LW specimens.

Gradient Nanostructured Tantalum by Thermal-Mechanical Ultrasonic Impact Energy.

PubMed

Chae, Jong-Min; Lee, Keun-Oh; Amanov, Auezhan

2018-03-20

Microstructural evolution and wear performance of Tantalum (Ta) treated by ultrasonic nanocrystalline surface modification (UNSM) at 25 and 1000 °C were reported. The UNSM treatment modified a surface along with subsurface layer with a thickness in the range of 20 to 150 µm, which depends on the UNSM treatment temperature, via the surface severe plastic deformation (S²PD) method. The cross-sectional microstructure of the specimens was observed by electron backscattered diffraction (EBSD) in order to confirm the microstructural alteration in terms of effective depth and refined grain size. The surface hardness measurement results, including depth profile, revealed that the hardness of the UNSM-treated specimens at both temperatures was increased in comparison with those of the untreated ones. The increase in UNSM treatment temperature led to a further increase in hardness. Moreover, both the UNSM-treated specimens with an increased hardness resulted in a higher resistance to wear in comparison with those of the untreated ones under dry conditions. The increase in hardness and induced compressive residual stress that depend on the formation of severe plastically deformed layer with the refined nano-grains are responsible for the enhancement in wear resistance. The findings of this study may be implemented in response to various industries that are related to strength improvement and wear enhancement issues of Ta.

Gradient Nanostructured Tantalum by Thermal-Mechanical Ultrasonic Impact Energy

PubMed Central

Chae, Jong-Min; Lee, Keun-Oh; Amanov, Auezhan

2018-01-01

Microstructural evolution and wear performance of Tantalum (Ta) treated by ultrasonic nanocrystalline surface modification (UNSM) at 25 and 1000 °C were reported. The UNSM treatment modified a surface along with subsurface layer with a thickness in the range of 20 to 150 µm, which depends on the UNSM treatment temperature, via the surface severe plastic deformation (S2PD) method. The cross-sectional microstructure of the specimens was observed by electron backscattered diffraction (EBSD) in order to confirm the microstructural alteration in terms of effective depth and refined grain size. The surface hardness measurement results, including depth profile, revealed that the hardness of the UNSM-treated specimens at both temperatures was increased in comparison with those of the untreated ones. The increase in UNSM treatment temperature led to a further increase in hardness. Moreover, both the UNSM-treated specimens with an increased hardness resulted in a higher resistance to wear in comparison with those of the untreated ones under dry conditions. The increase in hardness and induced compressive residual stress that depend on the formation of severe plastically deformed layer with the refined nano-grains are responsible for the enhancement in wear resistance. The findings of this study may be implemented in response to various industries that are related to strength improvement and wear enhancement issues of Ta. PMID:29558402

Biomechanical Strengthening of the Human Cornea Induced by Nanoplatform-Based Transepithelial Riboflavin/UV-A Corneal Cross-Linking.

PubMed

Labate, Cristina; Lombardo, Marco; Lombardo, Giuseppe; De Santo, Maria Penelope

2017-01-01

The purpose of this study was to investigate the biomechanical stiffening effect induced by nanoplatform-based transepithelial riboflavin/UV-A cross-linking protocol using atomic force microscopy (AFM). Twelve eye bank donor human sclerocorneal tissues were investigated using a commercial atomic force microscope operated in force spectroscopy mode. Four specimens underwent transepithelial corneal cross-linking using a hypotonic solution of 0.1% riboflavin with biodegradable polymeric nanoparticles of 2-hydroxypropyl-β-cyclodextrin plus enhancers (trometamol and ethylenediaminetetraacetic acid) and UV-A irradiation with a 10 mW/cm2 device for 9 minutes. After treatment, the corneal epithelium was removed using the Amoils brush, and the Young's modulus of the most anterior stroma was quantified as a function of scan rate by AFM. The results were compared with those collected from four specimens that underwent conventional riboflavin/UV-A corneal cross-linking and four untreated specimens. The average Young's modulus of the most anterior stroma after the nanoplatform-based transepithelial and conventional riboflavin/UV-A corneal cross-linking treatments was 2.5 times (P < 0.001) and 1.7 times (P < 0.001) greater than untreated controls respectively. The anterior stromal stiffness was significantly different between the two corneal cross-linking procedures (P < 0.001). The indentation depth decreased after corneal cross-linking treatments, ranging from an average of 2.4 ± 0.3 μm in untreated samples to an average of 1.2 ± 0.1 μm and 1.8 ± 0.1 μm after nanoplatform-based transepithelial and conventional cross-linking, respectively. The present nanotechnology-based transepithelial riboflavin/UV-A corneal cross-linking was effective to improve the biomechanical strength of the most anterior stroma of the human cornea.

Estimating False-Recent Classification for the Limiting-Antigen Avidity EIA and BED-Capture Enzyme Immunoassay in Vietnam: Implications for HIV-1 Incidence Estimates.

PubMed

Shah, Neha S; Duong, Yen T; Le, Linh-Vi; Tuan, Nguyen Anh; Parekh, Bharat S; Ha, Hoang Thi Thanh; Pham, Quang Duy; Cuc, Cao Thi Thu; Dobbs, Trudy; Tram, Tran Hong; Lien, Truong Thi Xuan; Wagar, Nick; Yang, Chunfu; Martin, Amy; Wolfe, Mitchell; Hien, Nguyen Tran; Kim, Andrea A

2017-06-01

Laboratory tests that can distinguish recent from long-term HIV infection are used to estimate HIV incidence in a population, but can potentially misclassify a proportion of long-term HIV infections as recent. Correct application of an assay requires determination of the proportion false recents (PFRs) as part of the assay characterization and for calculating HIV incidence in a local population using a HIV incidence assay. From April 2009 to December 2010, blood specimens were collected from HIV-infected individuals attending nine outpatient clinics (OPCs) in Vietnam (four from northern and five from southern Vietnam). Participants were living with HIV for ≥1 year and reported no antiretroviral (ARV) drug treatment. Basic demographic data and clinical information were collected. Specimens were tested with the BED capture enzyme immunoassay (BED-CEIA) and the Limiting-antigen (LAg)-Avidity EIA. PFR was estimated by dividing the number of specimens classified as recent by the total number of specimens; 95% confidence intervals (CI) were calculated. Specimens that tested recent had viral load testing performed. Among 1,813 specimens (north, n = 942 and south, n = 871), the LAg-Avidity EIA PFR was 1.7% (CI: 1.2-2.4) and differed by region [north 2.7% (CI: 1.8-3.9) versus south 0.7% (CI: 0.3-1.5); p = .002]. The BED-CEIA PFR was 2.3% (CI: 1.7-3.0) and varied by region [north 3.4% (CI: 2.4-4.7) versus south 1.0% (CI: 0.5-1.2), p < .001]. Excluding specimens with an undetectable VL, the LAg-Avidity EIA PFR was 1.2% (CI: 0.8-1.9) and the BED-CEIA PFR was 1.7% (CI: 1.2-2.4). The LAg-Avidity EIA PFR was lower than the BED-CEIA PFR. After excluding specimens with an undetectable VL, the PFR for both assays was similar. A low PFR should facilitate the implementation of the LAg-Avidity EIA for cross-sectional incidence estimates in Vietnam.

Estimating False-Recent Classification for the Limiting-Antigen Avidity EIA and BED-Capture Enzyme Immunoassay in Vietnam: Implications for HIV-1 Incidence Estimates

PubMed Central

Shah, Neha S.; Duong, Yen T.; Le, Linh-Vi; Tuan, Nguyen Anh; Parekh, Bharat S.; Thanh Ha, Hoang Thi; Pham, Quang Duy; Thu Cuc, Cao Thi; Dobbs, Trudy; Tram, Tran Hong; Xuan Lien, Truong Thi; Wagar, Nick; Yang, Chunfu; Martin, Amy; Wolfe, Mitchell; Hien, Nguyen Tran; Kim, Andrea A.

2017-01-01

Laboratory tests that can distinguish recent from long-term HIV infection are used to estimate HIV incidence in a population, but can potentially misclassify a proportion of long-term HIV infections as recent. Correct application of an assay requires determination of the proportion false recents (PFRs) as part of the assay characterization and for calculating HIV incidence in a local population using a HIV incidence assay. From April 2009 to December 2010, blood specimens were collected from HIV-infected individuals attending nine outpatient clinics (OPCs) in Vietnam (four from northern and five from southern Vietnam). Participants were living with HIV for ≥1 year and reported no antiretroviral (ARV) drug treatment. Basic demographic data and clinical information were collected. Specimens were tested with the BED capture enzyme immunoassay (BED-CEIA) and the Limiting-antigen (LAg)-Avidity EIA. PFR was estimated by dividing the number of specimens classified as recent by the total number of specimens; 95% confidence intervals (CI) were calculated. Specimens that tested recent had viral load testing performed. Among 1,813 specimens (north, n = 942 and south, n = 871), the LAg-Avidity EIA PFR was 1.7% (CI: 1.2–2.4) and differed by region [north 2.7% (CI: 1.8–3.9) versus south 0.7% (CI: 0.3–1.5); p = .002]. The BED-CEIA PFR was 2.3% (CI: 1.7–3.0) and varied by region [north 3.4% (CI: 2.4–4.7) versus south 1.0% (CI: 0.5–1.2), p < .001]. Excluding specimens with an undetectable VL, the LAg-Avidity EIA PFR was 1.2% (CI: 0.8–1.9) and the BED-CEIA PFR was 1.7% (CI: 1.2–2.4). The LAg-Avidity EIA PFR was lower than the BED-CEIA PFR. After excluding specimens with an undetectable VL, the PFR for both assays was similar. A low PFR should facilitate the implementation of the LAg-Avidity EIA for cross-sectional incidence estimates in Vietnam. PMID:28193090

Mechanical characterization of an additively manufactured Inconel 718 theta-shaped specimen

DOE PAGES

Cakmak, Ercan; Watkins, Thomas R.; Bunn, Jeffrey R.; ...

2015-11-20

Two sets of “theta”-shaped specimens were additively manufactured with Inconel 718 powders using an electron beam melting technique with two distinct scan strategies. Light optical microscopy, mechanical testing coupled with a digital image correlation (DIC) technique, finite element modeling, and neutron diffraction with in situ loading characterizations were conducted. The cross-members of the specimens were the focus. Light optical micrographs revealed that different microstructures were formed with different scan strategies. Ex situ mechanical testing revealed each build to be stable under load until ductility was observed on the cross-members before failure. The elastic moduli were determined by forming a correlationmore » between the elastic tensile stresses determined from FEM, and the elastic strains obtained from DIC. The lattice strains were mapped with neutron diffraction during in situ elastic loading; and a good correlation between the average axial lattice strains on the cross-member and those determined from the DIC analysis was found. Lastly, the spatially resolved stresses in the elastic deformation regime are derived from the lattice strains and increased with applied load, showing a consistent distribution along the cross-member.« less

Mechanical characterization of an additively manufactured Inconel 718 theta-shaped specimen

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

Cakmak, Ercan; Watkins, Thomas R.; Bunn, Jeffrey R.

Two sets of “theta”-shaped specimens were additively manufactured with Inconel 718 powders using an electron beam melting technique with two distinct scan strategies. Light optical microscopy, mechanical testing coupled with a digital image correlation (DIC) technique, finite element modeling, and neutron diffraction with in situ loading characterizations were conducted. The cross-members of the specimens were the focus. Light optical micrographs revealed that different microstructures were formed with different scan strategies. Ex situ mechanical testing revealed each build to be stable under load until ductility was observed on the cross-members before failure. The elastic moduli were determined by forming a correlationmore » between the elastic tensile stresses determined from FEM, and the elastic strains obtained from DIC. The lattice strains were mapped with neutron diffraction during in situ elastic loading; and a good correlation between the average axial lattice strains on the cross-member and those determined from the DIC analysis was found. Lastly, the spatially resolved stresses in the elastic deformation regime are derived from the lattice strains and increased with applied load, showing a consistent distribution along the cross-member.« less

Analysis and testing of axial compression in imperfect slender truss struts

NASA Technical Reports Server (NTRS)

Lake, Mark S.; Georgiadis, Nicholas

1990-01-01

The axial compression of imperfect slender struts for large space structures is addressed. The load-shortening behavior of struts with initially imperfect shapes and eccentric compressive end loading is analyzed using linear beam-column theory and results are compared with geometrically nonlinear solutions to determine the applicability of linear analysis. A set of developmental aluminum clad graphite/epoxy struts sized for application to the Space Station Freedom truss are measured to determine their initial imperfection magnitude, load eccentricity, and cross sectional area and moment of inertia. Load-shortening curves are determined from axial compression tests of these specimens and are correlated with theoretical curves generated using linear analysis.

Intrinsic microstructure of Si/GaAs heterointerfaces fabricated by surface-activated bonding at room temperature

NASA Astrophysics Data System (ADS)

Ohno, Yutaka; Yoshida, Hideto; Takeda, Seiji; Liang, Jianbo; Shigekawa, Naoteru

2018-02-01

The intrinsic microstructure of Si/GaAs heterointerfaces fabricated by surface-activated bonding at room temperature is examined by plane-view transmission electron microscopy (TEM) and cross-sectional scanning TEM using damage-free TEM specimens prepared only by mechanochemical etching. The bonded heterointerfaces include an As-deficient crystalline GaAs layer with a thickness of less than 1 nm and an amorphous Si layer with a thickness of approximately 3 nm, introduced by the irradiation of an Ar atom beam for surface activation before bonding. It is speculated that the interface resistance mainly originates from the As-deficient defects in the former layer.

Anisakiasis Causing Acute Dysentery in Malaysia.

PubMed

Amir, Amirah; Ngui, Romano; Ismail, Wan Hafiz Wan; Wong, Kum T; Ong, Jaxinthe S K; Lim, Yvonne A L; Lau, Yee-Ling; Mahmud, Rohela

2016-08-03

Human anisakiasis is a zoonosis acquired by eating raw or undercooked infected seafood. Herein, we report a case of acute dysentery caused by anisakiasis in a 64-year-old man in Malaysia. A colonoscopy was performed and a nematode larva was found penetrating the mucosa of the ascending colon. Bleeding was observed at the site of penetration. Y-shaped lateral epidermal cords were seen from the cross section of the worm, which is a prominent feature of Anisakis larva. Molecular analysis using polymerase chain reaction of cytochrome oxidase 2 (cox2) gene confirmed the specimen to be larva of Anisakis simplex. © The American Society of Tropical Medicine and Hygiene.

Corrosion on prehistoric Cu-Sn-alloys: the influence of artificial environment and storage

NASA Astrophysics Data System (ADS)

Mödlinger, Marianne; Piccardo, Paolo

2013-12-01

The paper contributes to the identification of different corrosion products detected on the cross-section specimens sampled from Bronze Age swords and one helmet found between 60-160 years ago. The objects are kept in 1889 built oak showcases at the Natural History Museum Vienna, having suffered unknown restoration treatments. The identified corrosion products not only affect further eventual treatment in conservation science of copper base objects but also contribute to identify the often unknown find context, which is meant to facilitate archaeological interpretation of the Bronze Age weapons. The analyses of the samples were carried out using SEM-EDXS-EBSD and optical microscopy.

10 CFR 26.111 - Checking the acceptability of the urine specimen.

Code of Federal Regulations, 2013 CFR

2013-01-01

... 10 Energy 1 2013-01-01 2013-01-01 false Checking the acceptability of the urine specimen. 26.111 Section 26.111 Energy NUCLEAR REGULATORY COMMISSION FITNESS FOR DUTY PROGRAMS Collecting Specimens for..., the collector shall measure the temperature of the specimen. The temperature-measuring device used...

10 CFR 26.111 - Checking the acceptability of the urine specimen.

Code of Federal Regulations, 2012 CFR

2012-01-01

... 10 Energy 1 2012-01-01 2012-01-01 false Checking the acceptability of the urine specimen. 26.111 Section 26.111 Energy NUCLEAR REGULATORY COMMISSION FITNESS FOR DUTY PROGRAMS Collecting Specimens for..., the collector shall measure the temperature of the specimen. The temperature-measuring device used...

10 CFR 26.111 - Checking the acceptability of the urine specimen.

Code of Federal Regulations, 2014 CFR

2014-01-01

... 10 Energy 1 2014-01-01 2014-01-01 false Checking the acceptability of the urine specimen. 26.111 Section 26.111 Energy NUCLEAR REGULATORY COMMISSION FITNESS FOR DUTY PROGRAMS Collecting Specimens for..., the collector shall measure the temperature of the specimen. The temperature-measuring device used...

10 CFR 26.113 - Splitting the urine specimen.

Code of Federal Regulations, 2013 CFR

2013-01-01

... 10 Energy 1 2013-01-01 2013-01-01 false Splitting the urine specimen. 26.113 Section 26.113 Energy NUCLEAR REGULATORY COMMISSION FITNESS FOR DUTY PROGRAMS Collecting Specimens for Testing § 26.113 Splitting the urine specimen. (a) Licensees and other entities may, but are not required to, use split...

10 CFR 26.115 - Collecting a urine specimen under direct observation.

Code of Federal Regulations, 2014 CFR

2014-01-01

... 10 Energy 1 2014-01-01 2014-01-01 false Collecting a urine specimen under direct observation. 26.115 Section 26.115 Energy NUCLEAR REGULATORY COMMISSION FITNESS FOR DUTY PROGRAMS Collecting Specimens for Testing § 26.115 Collecting a urine specimen under direct observation. (a) Procedures for...

10 CFR 26.135 - Split specimens.

Code of Federal Regulations, 2013 CFR

2013-01-01

... 10 Energy 1 2013-01-01 2013-01-01 false Split specimens. 26.135 Section 26.135 Energy NUCLEAR REGULATORY COMMISSION FITNESS FOR DUTY PROGRAMS Licensee Testing Facilities § 26.135 Split specimens. (a) If the FFD program follows split-specimen procedures, as described in § 26.113, the licensee testing...

10 CFR 26.113 - Splitting the urine specimen.

Code of Federal Regulations, 2012 CFR

2012-01-01

... 10 Energy 1 2012-01-01 2012-01-01 false Splitting the urine specimen. 26.113 Section 26.113 Energy NUCLEAR REGULATORY COMMISSION FITNESS FOR DUTY PROGRAMS Collecting Specimens for Testing § 26.113 Splitting the urine specimen. (a) Licensees and other entities may, but are not required to, use split...

10 CFR 26.135 - Split specimens.

Code of Federal Regulations, 2014 CFR

2014-01-01

... 10 Energy 1 2014-01-01 2014-01-01 false Split specimens. 26.135 Section 26.135 Energy NUCLEAR REGULATORY COMMISSION FITNESS FOR DUTY PROGRAMS Licensee Testing Facilities § 26.135 Split specimens. (a) If the FFD program follows split-specimen procedures, as described in § 26.113, the licensee testing...

10 CFR 26.135 - Split specimens.

Code of Federal Regulations, 2012 CFR

2012-01-01

... 10 Energy 1 2012-01-01 2012-01-01 false Split specimens. 26.135 Section 26.135 Energy NUCLEAR REGULATORY COMMISSION FITNESS FOR DUTY PROGRAMS Licensee Testing Facilities § 26.135 Split specimens. (a) If the FFD program follows split-specimen procedures, as described in § 26.113, the licensee testing...

10 CFR 26.115 - Collecting a urine specimen under direct observation.

Code of Federal Regulations, 2013 CFR

2013-01-01

... 10 Energy 1 2013-01-01 2013-01-01 false Collecting a urine specimen under direct observation. 26.115 Section 26.115 Energy NUCLEAR REGULATORY COMMISSION FITNESS FOR DUTY PROGRAMS Collecting Specimens for Testing § 26.115 Collecting a urine specimen under direct observation. (a) Procedures for...

10 CFR 26.115 - Collecting a urine specimen under direct observation.

Code of Federal Regulations, 2012 CFR

2012-01-01

... 10 Energy 1 2012-01-01 2012-01-01 false Collecting a urine specimen under direct observation. 26.115 Section 26.115 Energy NUCLEAR REGULATORY COMMISSION FITNESS FOR DUTY PROGRAMS Collecting Specimens for Testing § 26.115 Collecting a urine specimen under direct observation. (a) Procedures for...

10 CFR 26.113 - Splitting the urine specimen.

Code of Federal Regulations, 2014 CFR

2014-01-01

... 10 Energy 1 2014-01-01 2014-01-01 false Splitting the urine specimen. 26.113 Section 26.113 Energy NUCLEAR REGULATORY COMMISSION FITNESS FOR DUTY PROGRAMS Collecting Specimens for Testing § 26.113 Splitting the urine specimen. (a) Licensees and other entities may, but are not required to, use split...

10 CFR 26.109 - Urine specimen quantity.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 10 Energy 1 2010-01-01 2010-01-01 false Urine specimen quantity. 26.109 Section 26.109 Energy NUCLEAR REGULATORY COMMISSION FITNESS FOR DUTY PROGRAMS Collecting Specimens for Testing § 26.109 Urine specimen quantity. (a) Licensees and other entities who are subject to this subpart shall establish a...

10 CFR 26.115 - Collecting a urine specimen under direct observation.

Code of Federal Regulations, 2011 CFR

2011-01-01

... 10 Energy 1 2011-01-01 2011-01-01 false Collecting a urine specimen under direct observation. 26.115 Section 26.115 Energy NUCLEAR REGULATORY COMMISSION FITNESS FOR DUTY PROGRAMS Collecting Specimens for Testing § 26.115 Collecting a urine specimen under direct observation. (a) Procedures for...

10 CFR 26.113 - Splitting the urine specimen.

Code of Federal Regulations, 2011 CFR

2011-01-01

... 10 Energy 1 2011-01-01 2011-01-01 false Splitting the urine specimen. 26.113 Section 26.113 Energy NUCLEAR REGULATORY COMMISSION FITNESS FOR DUTY PROGRAMS Collecting Specimens for Testing § 26.113 Splitting the urine specimen. (a) Licensees and other entities may, but are not required to, use split...

10 CFR 26.115 - Collecting a urine specimen under direct observation.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 10 Energy 1 2010-01-01 2010-01-01 false Collecting a urine specimen under direct observation. 26.115 Section 26.115 Energy NUCLEAR REGULATORY COMMISSION FITNESS FOR DUTY PROGRAMS Collecting Specimens for Testing § 26.115 Collecting a urine specimen under direct observation. (a) Procedures for...

10 CFR 26.135 - Split specimens.

Code of Federal Regulations, 2011 CFR

2011-01-01

... 10 Energy 1 2011-01-01 2011-01-01 false Split specimens. 26.135 Section 26.135 Energy NUCLEAR REGULATORY COMMISSION FITNESS FOR DUTY PROGRAMS Licensee Testing Facilities § 26.135 Split specimens. (a) If the FFD program follows split-specimen procedures, as described in § 26.113, the licensee testing...

10 CFR 26.109 - Urine specimen quantity.

Code of Federal Regulations, 2011 CFR

2011-01-01

... 10 Energy 1 2011-01-01 2011-01-01 false Urine specimen quantity. 26.109 Section 26.109 Energy NUCLEAR REGULATORY COMMISSION FITNESS FOR DUTY PROGRAMS Collecting Specimens for Testing § 26.109 Urine specimen quantity. (a) Licensees and other entities who are subject to this subpart shall establish a...

10 CFR 26.135 - Split specimens.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 10 Energy 1 2010-01-01 2010-01-01 false Split specimens. 26.135 Section 26.135 Energy NUCLEAR REGULATORY COMMISSION FITNESS FOR DUTY PROGRAMS Licensee Testing Facilities § 26.135 Split specimens. (a) If the FFD program follows split-specimen procedures, as described in § 26.113, the licensee testing...

10 CFR 26.113 - Splitting the urine specimen.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 10 Energy 1 2010-01-01 2010-01-01 false Splitting the urine specimen. 26.113 Section 26.113 Energy NUCLEAR REGULATORY COMMISSION FITNESS FOR DUTY PROGRAMS Collecting Specimens for Testing § 26.113 Splitting the urine specimen. (a) Licensees and other entities may, but are not required to, use split...

Evaluation of fracture toughness and mechanical properties of ternary thiol-ene-methacrylate systems as resin matrix for dental restorative composites.

PubMed

Beigi, Saeed; Yeganeh, Hamid; Atai, Mohammad

2013-07-01

Study and evaluation of fracture toughness, flexural and dynamic mechanical properties, and crosslink density of ternary thiol-ene-methacrylate systems and comparison with corresponding conventional methacrylate system were considered in the present study. Urethane tetra allyl ether monomer (UTAE) was synthesized as ene monomer. Different formulations were prepared based on combination of UTAE, BisGMA/TEGDMA and a tetrathiol monomer (PETMP). The photocuring reaction was conducted under visible light using BD/CQ combination as photoinitiator system. Mechanical properties were evaluated via measuring flexural strength, flexural modulus and fracture toughness. Scanning electron microscopy (SEM) was utilized to study the morphology of the fractured specimen's cross section. Viscoelastic properties of the samples were also determined by dynamic mechanical thermal analysis (DMTA). The same study was performed on a conventional methacrylate system. The data were analyzed and compared by ANOVA and Tukey HSD tests (significance level=0.05). The results showed improvement in fracture toughness of the specimens containing thiol-ene moieties. DMTA revealed a lower glass transition temperature and more homogenous structure for thiol-ene containing specimens in comparison to the system containing merely methacrylate monomer. The flexural modulus and flexural strength of the specimens with higher thiol-ene content were lower than the neat methacrylate system. The SEM micrographs of the fractured surface of specimens with higher methacrylate content were smooth and mirror-like (shiny) which represent brittle fracture. The thiol-ene-methacrylate system can be used as resin matrix of dental composites with enhanced fracture toughness in comparison to the methacrylate analogous. Copyright © 2013 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.

An Evaluation of the Iosipescu Specimen for Composite Materials Shear Property Measurement. Ph.D. Thesis

NASA Technical Reports Server (NTRS)

Ho, Henjen

1991-01-01

A detailed evaluation of the suitability of the Iosipescu specimen tested in the modified Wyoming fixture is presented. An experimental investigation using conventional strain gage instrumentation and moire interferometry is performed. A finite element analysis of the Iosipescu shear test for unidirectional and cross-ply composites is used to assess the uniformity of the shear stress field in the vicinity of the notch, and demonstrate the effect of the nonuniform stress field upon the strain gage measurements used for the determination of composite shear moduli. From the test results for graphite-epoxy laminates, it is shown that the proximity of the load introduction point to the test section greatly influences the individual gage readings for certain fiber orientations but the effect upon shear modulus measurement is relatively unimportant. A numerical study of the load contact effect shows the sensitivity of some fiber configurations to the specimen/fixture contact mechanism and may account for the variations in the measured shear moduli. A comparison of the strain gage readings from one surface of a specimen with corresponding data from moire interferometry on the opposite face documented an extreme sensitivity of some fiber orientations to eccentric loading which induced twisting and yielded spurious shear stress-strain curves. In the numerical analysis, it is shown that the Iosipescu specimens for different fiber orientations have to be modeled differently in order to closely approximate the true loading conditions. Correction factors are needed to allow for the nonuniformity of the strain field and the use of the average shear stress in the shear modulus evaluation. The correction factors, which are determined for the region occupied by the strain gage rosette, are found to be dependent upon the material orthotropic ratio and the finite element models. Based upon the experimental and numerical results, recommendations for improving the reliability and accuracy of the shear modulus values are made, and the implications for shear strength measurement discussed. Further application of the Iosipescu shear test to woven fabric composites is presented. The limitations of the traditional strain gage instrumentation on the satin weave and high tow plain weave fabrics is discussed. Test results of a epoxy based aluminum particulate composite is also presented. A modification of the Iosipescu specimen is proposed and investigated experimentally and numerically. It is shown that the proposed new specimen design provides a more uniform shear stress field in the test section and greatly reduces the normal and shear stress concentrations in the vicinity of the notches. While the fabrication and the material cost of the proposed specimen is tremendously reduced, it is shown the accuracy of the shear modulus measurement is not sacrificed.

Experimental Investigation of Tensile Test on Connection of Cold-formed Cut-curved Steel Section

NASA Astrophysics Data System (ADS)

Sani, Mohd Syahrul Hisyam Mohd; Muftah, Fadhluhartini; Rahman, Nurul Farraheeda Abdul; Fakri Muda, Mohd

2017-08-01

Cold-formed steel (CFS) is widely used as structural and non-structural components such as roof trusses and purlin. A CFS channel section with double intermediate web stiffener and lipped is chosen based on the broader usage in roof truss construction. CFS section is cut to form cold-formed pre-cut-curved steel section and lastly strengthened by several types of method or likely known as connection to establish the cold-formed cut-curved steel (CFCCS) section. CFCCS is proposed to be used as a top chord section in the roof truss system. The CFCCS is to resist the buckling phenomena of the roof truss structure and reduced the compression effect on the top chord. The tensile test connection of CFCCS section, especially at the flange element with eight types of connection by welding, plate with self-drilling screw and combination is investigated. The flange element is the weakest part that must be solved first other than the web element because they are being cut totally, 100% of their length for curving process. The testing is done using a universal testing machine for a tensile load. From the experiment, specimen with full welding has shown as a good result with an ultimate load of 13.37 kN and reported having 35.41% when compared with normal specimen without any of connection methods. Furthermore, the experimental result is distinguished by using Eurocode 3. The failure of a full welding specimen is due to breaking at the welding location. Additionally, all specimens with either full weld or spot weld or combination failed due to breaking on weld connection, but specimen with flange plate and self-drilling screw failed due to tilting and bearing. Finally, the full welding specimen is chosen as a good connection to perform the strengthening method of CFCCS section.

Vise holds specimens for microscope

NASA Technical Reports Server (NTRS)

Greule, W. N.

1980-01-01

Convenient, miniature, spring-loaded clamp holds specimens for scanning electron microscope. Clamp is made out of nesting sections of studded angle-aluminum. Specimens are easier to mount and dismount with vise than with conductive adhesive or paint.

Seismic performance of interior precast concrete beam-column connections with T-section steel inserts under cyclic loading

NASA Astrophysics Data System (ADS)

Ketiyot, Rattapon; Hansapinyo, Chayanon

2018-04-01

An experimental investigation was conducted to study the performance of precast beam-column concrete connections using T-section steel inserts into the concrete beam and joint core, under reversed cyclic loading. Six 2/3-scale interior beam-column subassemblies, one monolithic concrete specimen and five precast concrete specimens were tested. One precast specimen was a simple connection for a gravity load resistant design. Other precast specimens were developed with different attributes to improve their seismic performance. The test results showed that the performance of the monolithic specimen M1 represented ductile seismic behavior. Failure of columns and joints could be prevented, and the failure of the frame occurred at the flexural plastic hinge formation at the beam ends, close to the column faces. For the precast specimens, the splitting crack along the longitudinal lapped splice was a major failure. The precast P5 specimen with double steel T-section inserts showed better seismic performance compared to the other precast models. However, the dowel bars connected to the steel inserts were too short to develop a bond. The design of the precast concrete beams with lap splice is needed for longer lap lengths and should be done at the beam mid span or at the low flexural stress region.

Complete embedding and close step-sectioning of radical prostatectomy specimens both increase detection of extra-prostatic extension, and correlate with increased disease-free survival by stage of prostate cancer patients.

PubMed

Desai, A; Wu, H; Sun, L; Sesterhenn, I A; Mostofi, F K; McLeod, D; Amling, C; Kusuda, L; Lance, R; Herring, J; Foley, J; Baldwin, D; Bishoff, J T; Soderdahl, D; Moul, J W

2002-01-01

The objectives of this work were to evaluate the efficacy of controlled close step-sectioned and whole-mounted radical prostatectomy specimen processing in prediction of clinical outcome as compared to the traditional processing techniques. Two-hundred and forty nine radical prostatectomy (RP) specimens were whole-mounted and close step-sectioned at caliper-measured 2.2-2.3 mm intervals. A group of 682 radical prostatectomy specimens were partially sampled as control. The RPs were performed during 1993-1999 with a mean follow-up of 29.3 months, pretreatment PSA of 0.1-40, and biopsy Gleason sums of 5-8. Disease-free survival based on biochemical or clinical recurrence and secondary intervention were computed using a Kaplan-Meier analysis. There were no significant differences in age at diagnosis, age at surgery, PSA at diagnosis, or biopsy Gleason between the two groups (P<0.05). Compared with the non-close step-sectioned group, the close step-sectioned group showed higher detection rates of extra-prostatic extension (215 (34.1%) vs, 128 (55.4%), P<0.01), and seminal vesicle invasion (50 (7.6%) vs 35 (14.7%), P<0.01). The close step-sectioned group correlated with greater 3-y disease-free survival in organ-confined (P<0.01) and specimen-confined (P<0.01) cases, over the non-uniform group. The close step-sectioned group showed significantly higher disease-free survival for cases with seminal vesicle invasion (P=0.046). No significant difference in disease-free survival was found for the positive margin group (P=0.39) between the close step-sectioned and non-uniform groups. The close step-sectioned technique correlates with increased disease-free survival rates for organ and specimen confined cases, possibly due to higher detection rates of extra-prostatic extension and seminal vesicle invasion. Close step-sectioning provides better assurance of organ-confined disease, resulting in enhanced prediction of outcome by pathological (TNM) stage.

ExFiT Flight Design and Structural Modeling for FalconLAUNCH VIII Sounding Rocket

DTIC Science & Technology

2010-03-01

frequencies of the test specimen. Next, the accelerometers were placed along the trailing edge of both the main wing and winglet sections. In the first...once again used however, the accelerometer originally in the winglet section was moved to the cut out portion of the main wing section. In this test...the part was struck on the joining section of the specimen connecting both main wing and winglet sections. Finally, the ping hammer was loaded with a

Evaluation of dual-color fluorescence in situ hybridization with peptide nucleic acid probes for the detection of Mycobacterium tuberculosis and non-tuberculous mycobacteria in clinical specimens.

PubMed

Kim, Namhee; Lee, Seung Hee; Yi, Jongyoun; Chang, Chulhun L

2015-09-01

Peptide nucleic acid (PNA) probes are artificial DNA analogues with a hydrophobic nature that can penetrate the mycobacterial cell wall. We evaluated a FISH method for simultaneous detection and identification of Mycobacterium tuberculosis (MTB) and non-tuberculous mycobacteria (NTM) in clinical respiratory specimens using differentially labeled PNA probes. PNA probes targeting the mycobacterial 16S ribosomal RNA were synthesized. The cross-reactivity of MTB- and NTM-specific probes was examined with reference strains and 10 other frequently isolated bacterial species. A total of 140 sputum specimens were analyzed, comprising 100 MTB-positive specimens, 21 NTM-positive specimens, and 19 MTB/NTM-negative specimens; all of them were previously confirmed by PCR and culture. The PNA FISH test results were graded by using the United States Centers for Disease Control and Prevention-recommended scale and compared with the results from the fluorochrome acid-fast bacterial stain. The MTB- and NTM-specific PNA probes showed no cross-reactivity with other tested bacterial species. The test results demonstrated 82.9% agreement with the culture results with diagnostic sensitivity of 80.2% and diagnostic specificity of 100.0% (kappa=0.52, 95% confidence interval: 0.370-0.676). Dual-color PNA FISH showed high specificity for detecting and identifying mycobacteria in clinical specimens. However, because of its relatively low sensitivity, this method could be more applicable to culture confirmation. In application to direct specimens, the possibility of false-negative results needs to be considered.

10 CFR 26.165 - Testing split specimens and retesting single specimens.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 10 Energy 1 2010-01-01 2010-01-01 false Testing split specimens and retesting single specimens. 26.165 Section 26.165 Energy NUCLEAR REGULATORY COMMISSION FITNESS FOR DUTY PROGRAMS Laboratories... laboratory or maintained in secure storage at the licensee testing facility, as required by § 26.135(a) and...

10 CFR 26.89 - Preparing to collect specimens for testing.

Code of Federal Regulations, 2014 CFR

2014-01-01

... 10 Energy 1 2014-01-01 2014-01-01 false Preparing to collect specimens for testing. 26.89 Section 26.89 Energy NUCLEAR REGULATORY COMMISSION FITNESS FOR DUTY PROGRAMS Collecting Specimens for Testing § 26.89 Preparing to collect specimens for testing. (a) When an individual has been notified of a...

10 CFR 26.117 - Preparing urine specimens for storage and shipping.

Code of Federal Regulations, 2013 CFR

2013-01-01

... 10 Energy 1 2013-01-01 2013-01-01 false Preparing urine specimens for storage and shipping. 26.117 Section 26.117 Energy NUCLEAR REGULATORY COMMISSION FITNESS FOR DUTY PROGRAMS Collecting Specimens for Testing § 26.117 Preparing urine specimens for storage and shipping. (a) Both the donor and the collector...

10 CFR 26.117 - Preparing urine specimens for storage and shipping.

Code of Federal Regulations, 2014 CFR

2014-01-01

... 10 Energy 1 2014-01-01 2014-01-01 false Preparing urine specimens for storage and shipping. 26.117 Section 26.117 Energy NUCLEAR REGULATORY COMMISSION FITNESS FOR DUTY PROGRAMS Collecting Specimens for Testing § 26.117 Preparing urine specimens for storage and shipping. (a) Both the donor and the collector...

10 CFR 26.117 - Preparing urine specimens for storage and shipping.

Code of Federal Regulations, 2012 CFR

2012-01-01

... 10 Energy 1 2012-01-01 2012-01-01 false Preparing urine specimens for storage and shipping. 26.117 Section 26.117 Energy NUCLEAR REGULATORY COMMISSION FITNESS FOR DUTY PROGRAMS Collecting Specimens for Testing § 26.117 Preparing urine specimens for storage and shipping. (a) Both the donor and the collector...

10 CFR 26.83 - Specimens to be collected.

Code of Federal Regulations, 2012 CFR

2012-01-01

... 10 Energy 1 2012-01-01 2012-01-01 false Specimens to be collected. 26.83 Section 26.83 Energy NUCLEAR REGULATORY COMMISSION FITNESS FOR DUTY PROGRAMS Collecting Specimens for Testing § 26.83 Specimens to be collected. Except as permitted under § 26.31(d)(5), licensees and other entities who are...

10 CFR 26.89 - Preparing to collect specimens for testing.

Code of Federal Regulations, 2012 CFR

2012-01-01

... 10 Energy 1 2012-01-01 2012-01-01 false Preparing to collect specimens for testing. 26.89 Section 26.89 Energy NUCLEAR REGULATORY COMMISSION FITNESS FOR DUTY PROGRAMS Collecting Specimens for Testing § 26.89 Preparing to collect specimens for testing. (a) When an individual has been notified of a...

10 CFR 26.107 - Collecting a urine specimen.

Code of Federal Regulations, 2013 CFR

2013-01-01

... 10 Energy 1 2013-01-01 2013-01-01 false Collecting a urine specimen. 26.107 Section 26.107 Energy NUCLEAR REGULATORY COMMISSION FITNESS FOR DUTY PROGRAMS Collecting Specimens for Testing § 26.107 Collecting a urine specimen. (a) The collector shall direct the donor to go into the room or stall used for...

10 CFR 26.83 - Specimens to be collected.

Code of Federal Regulations, 2014 CFR

2014-01-01

... 10 Energy 1 2014-01-01 2014-01-01 false Specimens to be collected. 26.83 Section 26.83 Energy NUCLEAR REGULATORY COMMISSION FITNESS FOR DUTY PROGRAMS Collecting Specimens for Testing § 26.83 Specimens to be collected. Except as permitted under § 26.31(d)(5), licensees and other entities who are...

10 CFR 26.107 - Collecting a urine specimen.

Code of Federal Regulations, 2012 CFR

2012-01-01

... 10 Energy 1 2012-01-01 2012-01-01 false Collecting a urine specimen. 26.107 Section 26.107 Energy NUCLEAR REGULATORY COMMISSION FITNESS FOR DUTY PROGRAMS Collecting Specimens for Testing § 26.107 Collecting a urine specimen. (a) The collector shall direct the donor to go into the room or stall used for...

10 CFR 26.83 - Specimens to be collected.

Code of Federal Regulations, 2013 CFR

2013-01-01

... 10 Energy 1 2013-01-01 2013-01-01 false Specimens to be collected. 26.83 Section 26.83 Energy NUCLEAR REGULATORY COMMISSION FITNESS FOR DUTY PROGRAMS Collecting Specimens for Testing § 26.83 Specimens to be collected. Except as permitted under § 26.31(d)(5), licensees and other entities who are...

10 CFR 26.89 - Preparing to collect specimens for testing.

Code of Federal Regulations, 2013 CFR

2013-01-01

... 10 Energy 1 2013-01-01 2013-01-01 false Preparing to collect specimens for testing. 26.89 Section 26.89 Energy NUCLEAR REGULATORY COMMISSION FITNESS FOR DUTY PROGRAMS Collecting Specimens for Testing § 26.89 Preparing to collect specimens for testing. (a) When an individual has been notified of a...

10 CFR 26.107 - Collecting a urine specimen.

Code of Federal Regulations, 2014 CFR

2014-01-01

... 10 Energy 1 2014-01-01 2014-01-01 false Collecting a urine specimen. 26.107 Section 26.107 Energy NUCLEAR REGULATORY COMMISSION FITNESS FOR DUTY PROGRAMS Collecting Specimens for Testing § 26.107 Collecting a urine specimen. (a) The collector shall direct the donor to go into the room or stall used for...

10 CFR 26.89 - Preparing to collect specimens for testing.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 10 Energy 1 2010-01-01 2010-01-01 false Preparing to collect specimens for testing. 26.89 Section 26.89 Energy NUCLEAR REGULATORY COMMISSION FITNESS FOR DUTY PROGRAMS Collecting Specimens for Testing § 26.89 Preparing to collect specimens for testing. (a) When an individual has been notified of a...

10 CFR 26.107 - Collecting a urine specimen.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 10 Energy 1 2010-01-01 2010-01-01 false Collecting a urine specimen. 26.107 Section 26.107 Energy NUCLEAR REGULATORY COMMISSION FITNESS FOR DUTY PROGRAMS Collecting Specimens for Testing § 26.107 Collecting a urine specimen. (a) The collector shall direct the donor to go into the room or stall used for...

10 CFR 26.107 - Collecting a urine specimen.

Code of Federal Regulations, 2011 CFR

2011-01-01

... 10 Energy 1 2011-01-01 2011-01-01 false Collecting a urine specimen. 26.107 Section 26.107 Energy NUCLEAR REGULATORY COMMISSION FITNESS FOR DUTY PROGRAMS Collecting Specimens for Testing § 26.107 Collecting a urine specimen. (a) The collector shall direct the donor to go into the room or stall used for...

10 CFR 26.117 - Preparing urine specimens for storage and shipping.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 10 Energy 1 2010-01-01 2010-01-01 false Preparing urine specimens for storage and shipping. 26.117 Section 26.117 Energy NUCLEAR REGULATORY COMMISSION FITNESS FOR DUTY PROGRAMS Collecting Specimens for Testing § 26.117 Preparing urine specimens for storage and shipping. (a) Both the donor and the collector...

10 CFR 26.83 - Specimens to be collected.

Code of Federal Regulations, 2011 CFR

2011-01-01

... 10 Energy 1 2011-01-01 2011-01-01 false Specimens to be collected. 26.83 Section 26.83 Energy NUCLEAR REGULATORY COMMISSION FITNESS FOR DUTY PROGRAMS Collecting Specimens for Testing § 26.83 Specimens to be collected. Except as permitted under § 26.31(d)(5), licensees and other entities who are...

10 CFR 26.83 - Specimens to be collected.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 10 Energy 1 2010-01-01 2010-01-01 false Specimens to be collected. 26.83 Section 26.83 Energy NUCLEAR REGULATORY COMMISSION FITNESS FOR DUTY PROGRAMS Collecting Specimens for Testing § 26.83 Specimens to be collected. Except as permitted under § 26.31(d)(5), licensees and other entities who are...

10 CFR 26.117 - Preparing urine specimens for storage and shipping.

Code of Federal Regulations, 2011 CFR

2011-01-01

... 10 Energy 1 2011-01-01 2011-01-01 false Preparing urine specimens for storage and shipping. 26.117 Section 26.117 Energy NUCLEAR REGULATORY COMMISSION FITNESS FOR DUTY PROGRAMS Collecting Specimens for Testing § 26.117 Preparing urine specimens for storage and shipping. (a) Both the donor and the collector...

10 CFR 26.89 - Preparing to collect specimens for testing.

Code of Federal Regulations, 2011 CFR

2011-01-01

... 10 Energy 1 2011-01-01 2011-01-01 false Preparing to collect specimens for testing. 26.89 Section 26.89 Energy NUCLEAR REGULATORY COMMISSION FITNESS FOR DUTY PROGRAMS Collecting Specimens for Testing § 26.89 Preparing to collect specimens for testing. (a) When an individual has been notified of a...

10 CFR 26.111 - Checking the acceptability of the urine specimen.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 10 Energy 1 2010-01-01 2010-01-01 false Checking the acceptability of the urine specimen. 26.111 Section 26.111 Energy NUCLEAR REGULATORY COMMISSION FITNESS FOR DUTY PROGRAMS Collecting Specimens for Testing § 26.111 Checking the acceptability of the urine specimen. (a) Immediately after the donor...

10 CFR 26.111 - Checking the acceptability of the urine specimen.

Code of Federal Regulations, 2011 CFR

2011-01-01

... 10 Energy 1 2011-01-01 2011-01-01 false Checking the acceptability of the urine specimen. 26.111 Section 26.111 Energy NUCLEAR REGULATORY COMMISSION FITNESS FOR DUTY PROGRAMS Collecting Specimens for Testing § 26.111 Checking the acceptability of the urine specimen. (a) Immediately after the donor...

Gallbladder Cancer: expert consensus statement

PubMed Central

Aloia, Thomas A; Járufe, Nicolas; Javle, Milind; Maithel, Shishir K; Roa, Juan C; Adsay, Volkan; Coimbra, Felipe J F; Jarnagin, William R

2015-01-01

An American Hepato-Pancreato-Biliary Association (AHPBA)-sponsored consensus meeting of expert panellists was convened on 15 January 2014 to review current evidence on the management of gallbladder carcinoma in order to establish practice guidelines. In summary, within high incidence areas, the assessment of routine gallbladder specimens should include the microscopic evaluation of a minimum of three sections and the cystic duct margin; specimens with dysplasia or proven cancer should be extensively sampled. Provided the patient is medically fit for surgery, data support the resection of all gallbladder polyps of >1.0 cm in diameter and those with imaging evidence of vascular stalks. The minimum staging evaluation of patients with suspected or proven gallbladder cancer includes contrasted cross-sectional imaging and diagnostic laparoscopy. Adequate lymphadenectomy includes assessment of any suspicious regional nodes, evaluation of the aortocaval nodal basin, and a goal recovery of at least six nodes. Patients with confirmed metastases to N2 nodal stations do not benefit from radical resection and should receive systemic and/or palliative treatments. Primary resection of patients with early T-stage (T1b–2) disease should include en bloc resection of adjacent liver parenchyma. Patients with T1b, T2 or T3 disease that is incidentally identified in a cholecystectomy specimen should undergo re-resection unless this is contraindicated by advanced disease or poor performance status. Re-resection should include complete portal lymphadenectomy and bile duct resection only when needed to achieve a negative margin (R0) resection. Patients with preoperatively staged T3 or T4 N1 disease should be considered for clinical trials of neoadjuvant chemotherapy. Following R0 resection of T2–4 disease in N1 gallbladder cancer, patients should be considered for adjuvant systemic chemotherapy and/or chemoradiotherapy. PMID:26172135

Gallbladder cancer: expert consensus statement.

PubMed

Aloia, Thomas A; Járufe, Nicolas; Javle, Milind; Maithel, Shishir K; Roa, Juan C; Adsay, Volkan; Coimbra, Felipe J F; Jarnagin, William R

2015-08-01

An American Hepato-Pancreato-Biliary Association (AHPBA)-sponsored consensus meeting of expert panellists was convened on 15 January 2014 to review current evidence on the management of gallbladder carcinoma in order to establish practice guidelines. In summary, within high incidence areas, the assessment of routine gallbladder specimens should include the microscopic evaluation of a minimum of three sections and the cystic duct margin; specimens with dysplasia or proven cancer should be extensively sampled. Provided the patient is medically fit for surgery, data support the resection of all gallbladder polyps of >1.0 cm in diameter and those with imaging evidence of vascular stalks. The minimum staging evaluation of patients with suspected or proven gallbladder cancer includes contrasted cross-sectional imaging and diagnostic laparoscopy. Adequate lymphadenectomy includes assessment of any suspicious regional nodes, evaluation of the aortocaval nodal basin, and a goal recovery of at least six nodes. Patients with confirmed metastases to N2 nodal stations do not benefit from radical resection and should receive systemic and/or palliative treatments. Primary resection of patients with early T-stage (T1b-2) disease should include en bloc resection of adjacent liver parenchyma. Patients with T1b, T2 or T3 disease that is incidentally identified in a cholecystectomy specimen should undergo re-resection unless this is contraindicated by advanced disease or poor performance status. Re-resection should include complete portal lymphadenectomy and bile duct resection only when needed to achieve a negative margin (R0) resection. Patients with preoperatively staged T3 or T4 N1 disease should be considered for clinical trials of neoadjuvant chemotherapy. Following R0 resection of T2-4 disease in N1 gallbladder cancer, patients should be considered for adjuvant systemic chemotherapy and/or chemoradiotherapy. © 2015 International Hepato-Pancreato-Biliary Association.

Audit of clinical-laboratory practices in haematology and blood transfusion at Muhimbili National Hospital in Tanzania.

PubMed

Makubi, Abel N; Meda, Collins; Magesa, Alex; Minja, Peter; Mlalasi, Juliana; Salum, Zubeda; Kweka, Rumisha E; Rwehabura, James; Quaresh, Amrana; Magesa, Pius M; Robert, David; Makani, Julie; Kaaya, Ephata

2012-10-01

In Tanzania, there is paucity of data for monitoring laboratory medicine including haematology. This therefore calls for audits of practices in haematology and blood transfusion in order to provide appraise practice and devise strategies that would result in improved quality of health care services. This descriptive cross-sectional study which audited laboratory practice in haematology and blood transfusion at Muhimbili National Hospital (MNH) aimed at assessing the pre-analytical stage of laboratory investigations including laboratory request forms and handling specimen processing in the haematology laboratory and assessing the chain from donor selection, blood component processing to administration of blood during transfusion. A national standard checklist was used to audit the laboratory request forms (LRF), phlebotomists' practices on handling and assessing the from donor selection to administration 6f blood during transfusion. Both interview and observations were used. A total of 195 LRF were audited and 100% of had incomplete information such as patients' identification numbers, time sample ordered, reason for request, summary of clinical assessment and differential diagnoses. The labelling of specimens was poorly done by phlebotomists/clinicians in 82% of the specimens. Also 65% (132/202) of the blood samples delivered in the haematology laboratory did not contain the recommended volume of blood. There was no laboratory request form specific for ordering blood and there were no guidelines for indication of blood transfusion in the wards/ clinics. The blood transfusion laboratory section was not participating in external quality assessment and the hospital transfusion committee was not in operation. It is recommended that a referral hospital like MNH should have a transfusion committee to provide an active forum to facilitate communication between those involved with transfusion, monitor, coordinate and audit blood transfusion practices as per national guidelines.

Incidence of Posterior Interosseous Nerve Trauma During Creation of the 3-4 Wrist Arthroscopy Portal in Cadavers.

PubMed

Cheah, Andre Eu-Jin; Le, Wei; Yao, Jeffrey

2017-04-01

To describe histologic evidence of nerve trauma during the creation and use of the 3-4 portal. Fourteen fresh-frozen cadaveric wrists were mounted on a custom-built frame that simulated a wrist arthroscopy traction tower. After the 3-4 portal was created in the usual manner, the skin was dissected off to identify possible trauma to the posterior interosseous nerve (PIN). Specimens were categorized into those where there was clearly no trauma to the PIN and those where trauma was possible. In the cases where trauma was possible, we harvested the PIN with a cuff of the proximal edge of the portal and examined the cross-sectional histology of the most distal sections for the presence of neural tissue. There was clearly no trauma to the PIN in 3 of the wrists during the creation of the 3-4 portal. In the remaining 11 wrists with possible trauma to the PIN, we identified axonal tissue on histologic examination at the proximal edge of the 3-4 portal in 7 of these specimens. In summary, 50% (7 of 14) of our specimens had visual and histologic evidence of trauma to the PIN. Based on the findings of this study, there may be more instances of trauma to the PIN during routine wrist arthroscopy than have been previously reported. Findings suggest that transection or injury to this nerve may not lead to any clinical sequelae. However, if there is an instance where a patient has persistent, otherwise unexplained, dorsal wrist pain after a wrist arthroscopy procedure, iatrogenic neuroma of the PIN may be responsible and should be considered. Copyright © 2017 Arthroscopy Association of North America. Published by Elsevier Inc. All rights reserved.

Correlation of endoscopic optical coherence tomography with histology

NASA Astrophysics Data System (ADS)

Westphal, Volker; Rollins, Andrew M.; Willis, Joseph; Sivak, Michael J., Jr.; Izatt, Joseph A.

2000-04-01

Optical Coherence Tomography (OCT) is a noninvasive optical imaging technique that allows high-resolution cross- sectional imaging of tissue microstructure. We have recently developed a system for endoscopic OCT (EOCT) to examine the gastrointestinal tract of humans in vivo. Compared to endoscopic ultrasonic devices it offers a higher resolution and does not require coupling gels or fluids. EOCT may lead to a versatile tool for biopsy site selection or optical biopsy itself. The EOCT unit is comprised of an interferometer unit with a high speed scanning reference arm and an endoscopically compatible radially scanning probe as the sample arm. Fast data acquisition allows real-time display. Temporal averaging for speckle reduction and a transformation to correct nonlinear scanning were included in the EOCT control software, both in real-time. During in vivo clinical trials, we have observe the structure of the mucosa and submucosa in several gastrointestinal organs as well as glands, blood vessels, pits, villi and crypts. The purpose of this study was to correlate images acquired in vitro with EOCT to corresponding histological sections. EOCT images were obtained on fresh specimens, which were then fixed in formalin and submitted for standard histology. Tissues examined were normal specimens, which were then fixed in formalin and submitted for standard histology. Tissues examined were normal specimens of stomach, ileum, colon and rectum. It was shown that he thickness of the mucosa correlates well with the first bright layer in EOCT. The R2-value was determined to be 0.69. The submucosa and the muscularis propria could be identified. Furthermore, we were able to show the effect of pressure on the tissue on the visible details in the EOCT images.

Filling material for a buried cavity in a collapse area using light-weighted foam and active feldspar

NASA Astrophysics Data System (ADS)

Cho, Jin Woo; Lee, Ju-hyoung; Kim, Sung-Wook; Choi, Eun-Kyeong

2017-04-01

Concrete which is generally used as filling material for a buried cavity has very high strength but significantly high self-load is considered its disadvantage. If it is used as filling material, the second collapse due to additional load, causing irreversible damage. If light-weighted foam and active feldspar are used to solve this problem, the second collapse can be prevented by reducing of self-load of filling material. In this study, the specimen was produced by mixing light-weighted foam, active feldspar and cement, and changes in the density, unconfined compressive strength and hydraulic conductivity were analyzed. Using the light-weighted foam could enable the adjustment of density of specimen between 0.5 g/cm3 and 1.7 g/cm3, and if the mixing ratio of the light-weighted foam increases, the specimen has more pores and smaller range of cross-sectional area. It is confirmed that it has direct correlation with the density, and if the specimen has more pores, the density of the specimen is lowered. The density of the specimen influences the unconfined compressive strength and the hydraulic conductivity, and it was also confirmed that the unconfined compressive strength could be adjusted between 0.6 MPa and 8 MPa and the hydraulic conductivity could be adjusted between 10-9cm/sec and 10-3cm/sec. These results indicated that we can adjust unconfined compressive strength and hydraulic conductivity of filling materials by changing the mixing amount of lightweight-weighted foam according to the requirements of the field condition. Keywords: filling material, buried cavity, light-weighted foam, feldspar Acknowledgement This research was supported by a Grant from a Strategic Research Project (Horizontal Drilling and Stabilization Technologies for Urban Search and Rescue (US&R) Operation) funded by the Korea Institute of Civil Engineering and Building Technology.

Permanent effect of a cryogenic spill on fracture properties of structural steels

NASA Astrophysics Data System (ADS)

Keseler, H.; Westermann, I.; Kandukuri, S. Y.; Nøkleby, J. O.; Holmedal, B.

2015-12-01

Fracture analysis of a standard construction steel platform deck, which had been exposed to a liquid nitrogen spill, showed that the brittle fracture started at a flaw in the weld as a consequence of low-temperature embrittlement and thermal stresses experienced by the material. In the present study, the permanent effect of a cryogenic spill on the fracture properties of carbon steels has been investigated. Charpy V-notch impact testing was carried out at 0 °C using specimens, from the platform deck material. The average impact energy appeared to be below requirements only for transverse specimens. No pre-existing damage was found when examining the fracture surfaces and cross sections in the scanning electron microscope. Specimens of the platform deck material and a DOMEX S355 MCD carbon steel were tensile tested immersed in liquid nitrogen. Both steels showed a considerable increase in yield- and fracture strength and a large increase in the Lüders strain compared to the room temperature behavior. A cryogenic spill was simulated by applying a constant tensile force to the specimens for 10 min, at -196 C. Subsequent tensile tests at room temperature showed no significant influence on the stress-strain curve of the specimens. A small amount of microcracks were found after holding a DOMEX S355 MCD specimen at a constant force below the yield point. In a platform deck material tensile tested to fracture in liquid nitrogen, cracks associated with elongated MnS inclusions were found through the whole test region. These cracks probably formed as a result of the inclusions having a higher thermal contraction rate than the steel, causing decohesion at the inclusion-matrix interface on cooling. Simultaneous deformation may have caused formation of cracks. Both the microcracks and sulphide related damage may give permanently reduced impact energy after a cryogenic exposure.

Investigation of the usefulness of fluorescein sodium fluorescence in stereotactic brain biopsy.

PubMed

Thien, Ady; Han, Julian Xinguang; Kumar, Krishan; Ng, Yew Poh; Rao, Jai Prashanth; Ng, Wai Hoe; King, Nicolas Kon Kam

2018-02-01

Intraoperative frozen section assessment, to confirm acquisition of pathological tissues, is used in stereotactic brain biopsy to minimise sampling errors. Limitations include the dependence on dedicated neuro-oncology pathologists and an increase in operative duration. We investigated the use of intraoperative fluorescein sodium, and compared it to frozen section assessment, for confirming pathological tissue samples in the stereotactic biopsy of gadolinium-contrast-enhancing brain lesions. This prospective observational study consisted of 18 consecutive patients (12 men; median age, 63 years) who underwent stereotactic biopsy of gadolinium-contrast-enhancing brain lesions with intravenous fluorescein sodium administration. Twenty-three specimens were obtained and examined for the presence of fluorescence using a microscope with fluorescence visualisation capability. Positive and negative predictive values were calculated based on the fluorescence status of the biopsy samples with its corresponding intraoperative frozen section and definitive histopathological diagnosis. Nineteen specimens (83%) were fluorescent and four (17%) were non-fluorescent. All 19 fluorescent specimens were confirmed to be lesional on intraoperative frozen section assessment and were suitable for histopathological diagnosis. Three of the non-fluorescent specimens were confirmed to be lesional on intraoperative frozen section assessment. One non-fluorescent specimen was non-diagnostic on frozen section and histological assessments. The positive predictive value was 100% and the negative predictive value was 25%. Fluorescein sodium fluorescence is as accurate as frozen section assessment in confirming sampling of pathological tissue in the stereotactic biopsy of gadolinium-contrast-enhancing brain lesions. Fluorescein sodium fluorescence-guided stereotactic biopsy is a useful addition to the neurosurgical armamentarium.

Reconstruction of upper lip muscle system by anatomy, magnetic resonance imaging, and serial histological sections.

PubMed

Bo, Chen; Ningbei, Yin

2014-01-01

Surgeons need references to undertake cleft lip repairs. We aimed to establish a three-dimensional model of upper lip muscles. We examined specimens from 2 adult cadaver heads and 8 adult cadaver lips, obtaining serial sections in the axial, sagittal, and coronal planes. Sections were stained to observe the philtrum, Cupid bow, vermilion, and nostril sill. Reconstruction was done with three-dimensional software (eg, 3D-DOCTOR, MicroMR). Parallel circular muscle fibers existed between modioli. The orbicularis oris deep layer contained fan muscle fibers inclining inward. Some ended at the anterior nasal crest. Others migrated to the depressor septum, crossed the midline, and migrated to the nasalis muscle. At the nostril floor, the depressor septum muscle bundle and ipsilateral orbicularis oris overlapped the nasalis muscle and the contralateral orbicularis oris. This construction shaped the nostril sill. The levator labii superioris alaeque nasi, levator labii superioris, and zygomaticus minor crossed the nasolabial groove and migrated to the superficial orbicularis oris, entering the outer edge of the nasal alar to the upper lip near the vermilion border and philtrum ridge, shaping Cupid bow. Contralateral deep orbicularis oris muscle fibers crossed the philtrum dimple to the lateral philtrum ridge (axial plane). Superficial reticular muscle fibers of the levator labii superioris, zygomaticus minor, zygomaticus major, and orbicularis oris inserted into the medial philtrum ridge (coronal plane). They intersected to form the philtrum ridge. A three-dimensional upper lip muscular system model was established that can be referenced for cleft lip repair and lip operations.

Histological biocompatibility of a stainless steel miniature glaucoma drainage device in humans: a case report.

PubMed

De Feo, Fabio; Jacobson, Stewart; Nyska, Abraham; Pagani, Paola; Traverso, Carlo Enrico

2009-06-01

The purpose of this study was to evaluate the histological biocompatibility of a stainless steel miniature glaucoma drainage device. Twenty-four months before death due to heart failure, this seventy-three-year-old female patient underwent filtration surgery for primary open-angle glaucoma uncontrolled in the right eye. The device was implanted at the limbus under a scleral flap. For histopathological evaluation, two corneoscleral specimens were embedded in methacrylate blocks sectioned to a thickness of 50 microns, polished and stained with periodic acid schiff. Some sections included a longitudinal cross-section of the implant. At the interface between the spur and the flange of the device and the cornea, there was a small shoulder of fibrous tissue. A thin, fibrous capsule covered the remainder of the body of the device up to the distal tip. No inflammatory cells occurred within the fibrous capsule. No material or blockage was noted within the lumen. Our results support the biological inertness of the device.

Optimization of wood plastic composite decks

NASA Astrophysics Data System (ADS)

Ravivarman, S.; Venkatesh, G. S.; Karmarkar, A.; Shivkumar N., D.; Abhilash R., M.

2018-04-01

Wood Plastic Composite (WPC) is a new class of natural fibre based composite material that contains plastic matrix reinforced with wood fibres or wood flour. In the present work, Wood Plastic Composite was prepared with 70-wt% of wood flour reinforced in polypropylene matrix. Mechanical characterization of the composite was done by carrying out laboratory tests such as tensile test and flexural test as per the American Society for Testing and Materials (ASTM) standards. Computer Aided Design (CAD) model of the laboratory test specimen (tensile test) was created and explicit finite element analysis was carried out on the finite element model in non-linear Explicit FE code LS - DYNA. The piecewise linear plasticity (MAT 24) material model was identified as a suitable model in LS-DYNA material library, describing the material behavior of the developed composite. The composite structures for decking application in construction industry were then optimized for cross sectional area and distance between two successive supports (span length) by carrying out various numerical experiments in LS-DYNA. The optimized WPC deck (Elliptical channel-2 E10) has 45% reduced weight than the baseline model (solid cross-section) considered in this study with the load carrying capacity meeting acceptance criterion (allowable deflection & stress) for outdoor decking application.

Determination of demineralization depth in tooth enamel exposed to abusive use of whitening gel using micro-Energy Dispersive X ray Fluorescence

NASA Astrophysics Data System (ADS)

Pessanha, Sofia; Coutinho, Sara; Carvalho, Maria Luisa; Silveira, João Miguel; Mata, António

2017-12-01

In this work, we present a methodology for the determination of the depth of demineralization in dental enamel caused by extended use of an Over-The-Counter (OTC) whitening product. Teeth whitening is a very common practice in Dentistry, but concerns have been raised regarding the invasiveness of the treatment, especially regarding OTC products, that can be used without medical supervision and sometimes with concentrations of active agent that exceed the allowed regulations. In this work, we studied tooth enamel samples, treated with a whitening product during an extended period of time, both directly on the enamel surface and in the cross-section. Specimens were analyzed using microbeam X-Ray Fluorescence (micro-XRF) using polycapillary optics to obtain a spot down to 25 μm. Due to the relatively large spot size of our setup point analysis of the cross-sections would be inadequate. This way, line scans were performed instead, before and after whitening, and using appropriate data treatment the depth of demineralization was inferred. The used methodology indicated an average demineralization depth of 25 μm, the same order of magnitude as the aprismatic enamel layer.

Failure behavior of concrete pile and super-structure dynamic response as a result of soil liquefaction during earthquake

NASA Astrophysics Data System (ADS)

Kaneda, Shogo; Hayashi, Kazuhiro; Hachimori, Wataru; Tamura, Shuji; Saito, Taiki

2017-10-01

In past earthquake disasters, numerous building structure piles were damaged by soil liquefaction occurring during the earthquake. Damage to these piles, because they are underground, is difficult to find. The authors aim to develop a monitoring method of pile damage based on superstructure dynamic response. This paper investigated the relationship between the damage of large cross section cementitious piles and the dynamic response of the super structure using a centrifuge test apparatus. A dynamic specimen used simple cross section pile models consisting of aluminum rod and mortar, a saturated soil (Toyoura sand) of a relative density of 40% and a super structure model of a natural period of 0.63sec. In the shaking table test under a 50G field (length scale of 1/50), excitation was a total of 3 motions scaled from the Rinkai wave at different amplitudes. The maximum acceleration of each of the excitations was 602gal, 336gal and 299gal. The centrifuge test demonstrated the liquefaction of saturated soil and the failure behavior of piles. In the test result, the damage of piles affected the predominant period of acceleration response spectrum on the footing of the superstructure.

31 CFR 537.527 - Importation into the United States of Burmese-origin animals and specimens.

Code of Federal Regulations, 2010 CFR

2010-07-01

... Burmese-origin animals and specimens. 537.527 Section 537.527 Money and Finance: Treasury Regulations... Importation into the United States of Burmese-origin animals and specimens. Specific licenses may be issued on a case-by-case basis authorizing the importation into the United States of animals and specimens of...

10 CFR 26.95 - Conducting an initial test for alcohol using a breath specimen.

Code of Federal Regulations, 2013 CFR

2013-01-01

... 10 Energy 1 2013-01-01 2013-01-01 false Conducting an initial test for alcohol using a breath specimen. 26.95 Section 26.95 Energy NUCLEAR REGULATORY COMMISSION FITNESS FOR DUTY PROGRAMS Collecting Specimens for Testing § 26.95 Conducting an initial test for alcohol using a breath specimen. (a) The...

10 CFR 26.95 - Conducting an initial test for alcohol using a breath specimen.

Code of Federal Regulations, 2012 CFR

2012-01-01

... 10 Energy 1 2012-01-01 2012-01-01 false Conducting an initial test for alcohol using a breath specimen. 26.95 Section 26.95 Energy NUCLEAR REGULATORY COMMISSION FITNESS FOR DUTY PROGRAMS Collecting Specimens for Testing § 26.95 Conducting an initial test for alcohol using a breath specimen. (a) The...

10 CFR 26.95 - Conducting an initial test for alcohol using a breath specimen.

Code of Federal Regulations, 2014 CFR

2014-01-01

... 10 Energy 1 2014-01-01 2014-01-01 false Conducting an initial test for alcohol using a breath specimen. 26.95 Section 26.95 Energy NUCLEAR REGULATORY COMMISSION FITNESS FOR DUTY PROGRAMS Collecting Specimens for Testing § 26.95 Conducting an initial test for alcohol using a breath specimen. (a) The...

10 CFR 26.95 - Conducting an initial test for alcohol using a breath specimen.

Code of Federal Regulations, 2011 CFR

2011-01-01

... 10 Energy 1 2011-01-01 2011-01-01 false Conducting an initial test for alcohol using a breath specimen. 26.95 Section 26.95 Energy NUCLEAR REGULATORY COMMISSION FITNESS FOR DUTY PROGRAMS Collecting Specimens for Testing § 26.95 Conducting an initial test for alcohol using a breath specimen. (a) The...

10 CFR 26.95 - Conducting an initial test for alcohol using a breath specimen.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 10 Energy 1 2010-01-01 2010-01-01 false Conducting an initial test for alcohol using a breath specimen. 26.95 Section 26.95 Energy NUCLEAR REGULATORY COMMISSION FITNESS FOR DUTY PROGRAMS Collecting Specimens for Testing § 26.95 Conducting an initial test for alcohol using a breath specimen. (a) The...

Experimental and numerical study of the failure process and energy mechanisms of rock-like materials containing cross un-persistent joints under uniaxial compression.

PubMed

Cao, Rihong; Cao, Ping; Lin, Hang; Fan, Xiang

2017-01-01

Joints and fissures in natural rocks have a significant influence on the stability of the rock mass, and it is often necessary to evaluate strength failure and crack evolution behavior. In this paper, based on experimental tests and numerical simulation (PFC2D), the macro-mechanical behavior and energy mechanism of jointed rock-like specimens with cross non-persistent joints under uniaxial loading were investigated. The focus was to study the effect of joint dip angle α and intersection angle γ on the characteristic stress, the coalescence modes and the energy release of jointed rock-like specimens. For specimens with γ = 30° and 45°, the UCS (uniaxial compression strength), CIS (crack initiation stress) and CDiS (critical dilatancy stress) increase as α increases from 0° to 75°. When γ = 60° and 75°, the UCS, CIS and CDiS increase as α increases from 0° to 60° and decrease when α is over 60°. Both the inclination angle α and intersection angle γ have great influence on the failure pattern of pre-cracked specimens. With different α and γ, specimens exhibit 4 kinds of failure patterns. Both the experimental and numerical results show that the energy of a specimen has similar trends with characteristic stress as α increases.

Deformation behavior of micro-indentation defects under uniaxial and biaxial loads

NASA Astrophysics Data System (ADS)

Ma, Zhichao; Zhao, Hongwei; Lu, Shuai; Li, Hailian; Liu, Changyi; Liu, Xianhua

2015-09-01

The microdefects of structure frequently act as the source to generate initial cracks and lead to the fracture failure. Study on the deformation behaviors of embedded defects would be conducive to better understand the failure mechanisms of structural materials. Micro-indentation technique was applied to prepare the initial indentations as embedded surface defects at the gauge length section and central section of a cross-shaped AZ31B magnesium alloy specimen. A novel in situ biaxial tensile device was developed to apply the synchronous biaxial loads. Via the observation by an optical microscope with three-dimensional imaging and measurement functions, the changing laws of the indentation topographies under uniaxial and biaxial tensile loads were discussed. Compared with the gauge length section, the increasing trend of the indentation length of the central section was relatively flat, and the decreasing trend of the indentation depth was more significant. The changes of indentation topographies were explained by the Poisson effect, and the significant plastic tensile stress has led to the releasing of the residual stress around the indentation location and also promoted the planarization of the pileup.

Deformation behavior of micro-indentation defects under uniaxial and biaxial loads.

PubMed

Ma, Zhichao; Zhao, Hongwei; Lu, Shuai; Li, Hailian; Liu, Changyi; Liu, Xianhua

2015-09-01

The microdefects of structure frequently act as the source to generate initial cracks and lead to the fracture failure. Study on the deformation behaviors of embedded defects would be conducive to better understand the failure mechanisms of structural materials. Micro-indentation technique was applied to prepare the initial indentations as embedded surface defects at the gauge length section and central section of a cross-shaped AZ31B magnesium alloy specimen. A novel in situ biaxial tensile device was developed to apply the synchronous biaxial loads. Via the observation by an optical microscope with three-dimensional imaging and measurement functions, the changing laws of the indentation topographies under uniaxial and biaxial tensile loads were discussed. Compared with the gauge length section, the increasing trend of the indentation length of the central section was relatively flat, and the decreasing trend of the indentation depth was more significant. The changes of indentation topographies were explained by the Poisson effect, and the significant plastic tensile stress has led to the releasing of the residual stress around the indentation location and also promoted the planarization of the pileup.

Matrix vesicles in the fibrous cap of atherosclerotic plaque: possible contribution to plaque rupture

PubMed Central

Bobryshev, Y V; Killingsworth, M C; Lord, R S A; Grabs, A J

2008-01-01

Plaque rupture is the most common type of plaque complication and leads to acute ischaemic events such as myocardial infarction and stroke. Calcification has been suggested as a possible indicator of plaque instability. Although the role of matrix vesicles in the initial stages of arterial calcification has been recognized, no studies have yet been carried out to examine a possible role of matrix vesicles in plaque destabilization. Tissue specimens selected for the present study represented carotid specimens obtained from patients undergoing carotid endarterectomy. Serial frozen cross-sections of the tissue specimens were cut and mounted on glass slides. The thickness of the fibrous cap (FCT) in each advanced atherosclerotic lesion, containing a well developed lipid/necrotic core, was measured at its narrowest sites in sets of serial sections. According to established criteria, atherosclerotic plaque specimens were histologically subdivided into two groups: vulnerable plaques with thin fibrous caps (FCT <100 μm) and presumably stable plaques, in which fibrous caps were thicker than 100 μm. Twenty-four carotid plaques (12 vulnerable and 12 presumably stable plaques) were collected for the present analysis of matrix vesicles in fibrous caps. In order to provide a sufficient number of representative areas from each plaque, laser capture microdissection (LCM) was carried out. The quantification of matrix vesicles in ultrathin sections of vulnerable and stable plaques revealed that the numbers of matrix vesicles were significantly higher in fibrous caps of vulnerable plaques than those in stable plaques (8.908±0.544 versus 6.208±0.467 matrix vesicles per 1.92 μm2 standard area; P= 0.0002). Electron microscopy combined with X-ray elemental microanalysis showed that some matrix vesicles in atherosclerotic plaques were undergoing calcification and were characterized by a high content of calcium and phosphorus. The percentage of calcified matrix vesicles/microcalcifications was significantly higher in fibrous caps in vulnerable plaques compared with that in stable plaques (6.705±0.436 versus 5.322±0A94; P= 0.0474). The findings reinforce a view that the texture of the extracellular matrix in the thinning fibrous cap of atherosclerotic plaque is altered and this might contribute to plaque destabilization. PMID:18194456

Novel region of interest interrogation technique for diffusion tensor imaging analysis in the canine brain.

PubMed

Li, Jonathan Y; Middleton, Dana M; Chen, Steven; White, Leonard; Ellinwood, N Matthew; Dickson, Patricia; Vite, Charles; Bradbury, Allison; Provenzale, James M

2017-08-01

Purpose We describe a novel technique for measuring diffusion tensor imaging metrics in the canine brain. We hypothesized that a standard method for region of interest placement could be developed that is highly reproducible, with less than 10% difference in measurements between raters. Methods Two sets of canine brains (three seven-week-old full-brains and two 17-week-old single hemispheres) were scanned ex-vivo on a 7T small-animal magnetic resonance imaging system. Strict region of interest placement criteria were developed and then used by two raters to independently measure diffusion tensor imaging metrics within four different white-matter regions within each specimen. Average values of fractional anisotropy, radial diffusivity, and the three eigenvalues (λ1, λ2, and λ3) within each region in each specimen overall and within each individual image slice were compared between raters by calculating the percentage difference between raters for each metric. Results The mean percentage difference between raters for all diffusion tensor imaging metrics when pooled by each region and specimen was 1.44% (range: 0.01-5.17%). The mean percentage difference between raters for all diffusion tensor imaging metrics when compared by individual image slice was 2.23% (range: 0.75-4.58%) per hemisphere. Conclusion Our results indicate that the technique described is highly reproducible, even when applied to canine specimens of differing age, morphology, and image resolution. We propose this technique for future studies of diffusion tensor imaging analysis in canine brains and for cross-sectional and longitudinal studies of canine brain models of human central nervous system disease.

Microstructural evolution and micromechanical properties of gamma-irradiated Au ball bonds

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

Yusoff, Wan Yusmawati Wan, E-mail: yusmawati@upnm.edu.my; Ismail, Roslina, E-mail: roslina.ismail@ukm.my; Jalar, Azman, E-mail: azmn@ukm.my

2014-07-01

The effect of gamma radiation on the mechanical and structural properties of gold ball bonds was investigated. Gold wires from thermosonic wire bonding were exposed to gamma rays from a Cobalt-60 source at a low dose (5 Gy). The load–depth curve of nanoindentation for the irradiated gold wire bond has an apparent staircase shape during loading compared to the as-received sample. The hardness of the specimens calculated from the nanoindentation shows an increase in value from 0.91 to 1.09 GPa for specimens after exposure. The reduced elastic modulus for irradiated specimens significantly increased as well, with values from 75.18 tomore » 98.55 GPa. The change in intrinsic properties due to gamma radiation was investigated using dual-focused ion beam and high-resolution transmission electron microscope analysis. The dual-focused ion beam and high-resolution transmission electron microscope images confirmed the changes in grain structure and the presence of dislocations. The scanning electron microscope micrographs of focused ion beam cross sections showed that the grain structure of the gold became elongated and smaller after exposure to gamma rays. Meanwhile, high-resolution transmission electron microscopy provided evidence that gamma radiation induced dislocation of the atomic arrangement. - Highlights: • Nanoindentation technique provides a detailed characterisation of Au ball bond. • P–h curve of irradiated Au ball bond shows an apparent pop-in event. • Hardness and reduced modulus increased after exposure. • Elongated and smaller grain structure in irradiated specimens • Prevalent presence of dislocations in the atomic arrangement.« less

Addressing the Analytic Challenges of Cross-Sectional Pediatric Pneumonia Etiology Data.

PubMed

Hammitt, Laura L; Feikin, Daniel R; Scott, J Anthony G; Zeger, Scott L; Murdoch, David R; O'Brien, Katherine L; Deloria Knoll, Maria

2017-06-15

Despite tremendous advances in diagnostic laboratory technology, identifying the pathogen(s) causing pneumonia remains challenging because the infected lung tissue cannot usually be sampled for testing. Consequently, to obtain information about pneumonia etiology, clinicians and researchers test specimens distant to the site of infection. These tests may lack sensitivity (eg, blood culture, which is only positive in a small proportion of children with pneumonia) and/or specificity (eg, detection of pathogens in upper respiratory tract specimens, which may indicate asymptomatic carriage or a less severe syndrome, such as upper respiratory infection). While highly sensitive nucleic acid detection methods and testing of multiple specimens improve sensitivity, multiple pathogens are often detected and this adds complexity to the interpretation as the etiologic significance of results may be unclear (ie, the pneumonia may be caused by none, one, some, or all of the pathogens detected). Some of these challenges can be addressed by adjusting positivity rates to account for poor sensitivity or incorporating test results from controls without pneumonia to account for poor specificity. However, no classical analytic methods can account for measurement error (ie, sensitivity and specificity) for multiple specimen types and integrate the results of measurements for multiple pathogens to produce an accurate understanding of etiology. We describe the major analytic challenges in determining pneumonia etiology and review how the common analytical approaches (eg, descriptive, case-control, attributable fraction, latent class analysis) address some but not all challenges. We demonstrate how these limitations necessitate a new, integrated analytical approach to pneumonia etiology data. © The Author 2017. Published by Oxford University Press for the Infectious Diseases Society of America.

Is endoscopic forceps biopsy enough for a definitive diagnosis of gastric epithelial neoplasia?

PubMed

Lee, Chang Kyun; Chung, Il-Kwun; Lee, Suck-Ho; Kim, Sang Pil; Lee, Sae Hwan; Lee, Tae Hoon; Kim, Hong-Soo; Park, Sang-Heum; Kim, Sun-Joo; Lee, Ji-Hye; Cho, Hyun Deuk; Oh, Mee-Hye

2010-09-01

Endoscopic forceps biopsy (EFB) as the primary histological diagnosis of gastric epithelial neoplasia (GEN) is debated in the era of endoscopic resection (ER). Our aim was to investigate the diagnostic reliability of EFB in patients with GEN compared with ER specimens as the reference standard for the final diagnosis in a large consecutive series. This was a cross-sectional retrospective study at a tertiary-referral center. A total of 354 consecutive patients with 397 GENs underwent ER (endoscopic mucosal resection or endoscopic submucosal dissection). Discrepancy rates between the histological results from EFB and ER specimens were assessed. Discrepancies that could affect patient outcome or clinical care were considered major. The overall histological discrepancy rate between EFB and ER specimens was 44.5% (95% confidence interval [CI], 39.7-49.5%) among the enrolled patients. The overall discrepancy rate was significantly higher in the intraepithelial neoplasia (IEN) group than in the carcinoma group (49.8% vs 25.6%, P < 0.001). The major discrepancy rate was also significantly higher in the IEN group than in the carcinoma group (36.6% vs 7.0%, P < 0.001). In subgroup analysis of the IEN group, a major histological discrepancy rate of 33.6% (70/208) for low-grade and 42.7% (44/103) for high-grade IEN was found, respectively. Endoscopic forceps biopsy was insufficient for a definitive diagnosis and therapeutic planning in patients with GEN. ER should be considered as not only definitive treatment but also a procedure for a precise histological diagnosis for lesions initially assessed as GEN by forceps biopsy specimens.

Measurement of Gene Expression in Archival Paraffin-Embedded Tissues

PubMed Central

Cronin, Maureen; Pho, Mylan; Dutta, Debjani; Stephans, James C.; Shak, Steven; Kiefer, Michael C.; Esteban, Jose M.; Baker, Joffre B.

2004-01-01

Throughout the last decade many laboratories have shown that mRNA levels in formalin-fixed and paraffin-embedded (FPE) tissue specimens can be quantified by reverse transcriptase-polymerase chain reaction (RT-PCR) techniques despite the extensive RNA fragmentation that occurs in tissues so preserved. We have developed RT-PCR methods that are sensitive, precise, and that have multianalyte capability for potential wide use in clinical research and diagnostic assays. Here it is shown that the extent of fragmentation of extracted FPE tissue RNA significantly increases with archive storage time. Probe and primer sets for RT-PCR assays based on amplicons that are both short and homogeneous in length enable effective reference gene-based data normalization for cross comparison of specimens that differ substantially in age. A 48-gene assay used to compare gene expression profiles from the same breast cancer tissue that had been either frozen or FPE showed very similar profiles after reference gene-based normalization. A 92-gene assay, using RNA extracted from three 10-μm FPE sections of archival breast cancer specimens (dating from 1985 to 2001) yielded analyzable data for these genes in all 62 tested specimens. The results were substantially concordant when estrogen receptor, progesterone receptor, and HER2 receptor status determined by RT-PCR was compared with immunohistochemistry assays for these receptors. Furthermore, the results highlight the advantages of RT-PCR over immunohistochemistry with respect to quantitation and dynamic range. These findings support the development of RT-PCR analysis of FPE tissue RNA as a platform for multianalyte clinical diagnostic tests. PMID:14695316

Addressing the Analytic Challenges of Cross-Sectional Pediatric Pneumonia Etiology Data

PubMed Central

Feikin, Daniel R.; Scott, J. Anthony G.; Zeger, Scott L.; Murdoch, David R.; O’Brien, Katherine L.; Deloria Knoll, Maria

2017-01-01

Abstract Despite tremendous advances in diagnostic laboratory technology, identifying the pathogen(s) causing pneumonia remains challenging because the infected lung tissue cannot usually be sampled for testing. Consequently, to obtain information about pneumonia etiology, clinicians and researchers test specimens distant to the site of infection. These tests may lack sensitivity (eg, blood culture, which is only positive in a small proportion of children with pneumonia) and/or specificity (eg, detection of pathogens in upper respiratory tract specimens, which may indicate asymptomatic carriage or a less severe syndrome, such as upper respiratory infection). While highly sensitive nucleic acid detection methods and testing of multiple specimens improve sensitivity, multiple pathogens are often detected and this adds complexity to the interpretation as the etiologic significance of results may be unclear (ie, the pneumonia may be caused by none, one, some, or all of the pathogens detected). Some of these challenges can be addressed by adjusting positivity rates to account for poor sensitivity or incorporating test results from controls without pneumonia to account for poor specificity. However, no classical analytic methods can account for measurement error (ie, sensitivity and specificity) for multiple specimen types and integrate the results of measurements for multiple pathogens to produce an accurate understanding of etiology. We describe the major analytic challenges in determining pneumonia etiology and review how the common analytical approaches (eg, descriptive, case-control, attributable fraction, latent class analysis) address some but not all challenges. We demonstrate how these limitations necessitate a new, integrated analytical approach to pneumonia etiology data. PMID:28575372

Investigating Delamination Migration in Composite Tape Laminates

NASA Technical Reports Server (NTRS)

Ratcliffe, James G.; DeCarvalho, Nelson V.

2014-01-01

A modification to a recently developed test specimen designed to investigate migration of a delamination between neighboring ply interfaces in tape laminates is presented. The specimen is a cross-ply laminated beam consisting of 40 plies with a polytetrafluoroethylene insert spanning part way along its length. The insert is located between a lower 0-degree ply (specimen length direction) and a stack of four 90-degree plies (specimen width direction). The modification involved a stacking sequence that promotes stable delamination growth prior to migration, and included a relocation of the insert from the specimen midplane to the interface between plies 14 and 15. Specimens were clamped at both ends onto a rigid baseplate and loaded on their upper surface via a piano hinge assembly, resulting in a predominantly flexural loading condition. Tests were conducted with the load-application point positioned at various locations along a specimen's span. This position affected the sequence of damage events during a test.

Enhancing the Specificity of the COBAS AMPLICOR CT/NG Test for Neisseria gonorrhoeae by Retesting Specimens with Equivocal Results

PubMed Central

Van Der Pol, Barbara; Martin, David H.; Schachter, Julius; Quinn, Thomas C.; Gaydos, Charlotte A.; Jones, Robert B.; Crotchfelt, Kimberly; Moncada, Jeanne; Jungkind, D.; Turner, Buffy; Peyton, Cynthia; Kelly, James F.; Weiss, Judith B.; Rosenstraus, Maurice

2001-01-01

The COBAS AMPLICOR CT/NG test for Neisseria gonorrhoeae cross-reacts with certain strains of nonpathogenic Neisseria species. In some strains, the target sequence is identical to that of N. gonorrhoeae, whereas other strains have a small number of mismatches within the regions recognized by the primers or probe used in the COBAS AMPLICOR NG test. These cross-reactive strains are occasionally present in urogenital specimens, causing false-positive results in the COBAS AMPLICOR NG test. Analysis of the data generated in a large multicenter clinical trial showed that 2.9% of the specimens gave signals between A660s of 0.2 and 3.5 but that one-half of these equivocal specimens did not contain N. gonorrhoeae. Most of these equivocal specimens were correctly classified as true positive or true negative by retesting in duplicate and defining a PCR-positive result as two of three results with an A660 of ≥2.0. If specimens had been classified as positive or negative based on a single test result using a cutoff of an A660 of 0.2, specificity would have ranged from 96.2 to 98.9% depending on specimen type, sex, and presence of symptoms. By employing the equivocal zone-retesting algorithm, specificity increased to 98.6 to 99.9% with little effect (0.1 to 4.9% decrease) on sensitivity in most specimen types, enabling the test to achieve a positive predictive value of at least 90% in populations with a prevalence of 4% or higher. In lower-prevalence populations, the test could be used to screen for presumptive infections that would have to be confirmed by an independent test. PMID:11526134

Skin age testing criteria: characterization of human skin structures by 500 MHz MRI multiple contrast and image processing.

PubMed

Sharma, Rakesh

2010-07-21

Ex vivo magnetic resonance microimaging (MRM) image characteristics are reported in human skin samples in different age groups. Human excised skin samples were imaged using a custom coil placed inside a 500 MHz NMR imager for high-resolution microimaging. Skin MRI images were processed for characterization of different skin structures. Contiguous cross-sectional T1-weighted 3D spin echo MRI, T2-weighted 3D spin echo MRI and proton density images were compared with skin histopathology and NMR peaks. In all skin specimens, epidermis and dermis thickening and hair follicle size were measured using MRM. Optimized parameters TE and TR and multicontrast enhancement generated better MRI visibility of different skin components. Within high MR signal regions near to the custom coil, MRI images with short echo time were comparable with digitized histological sections for skin structures of the epidermis, dermis and hair follicles in 6 (67%) of the nine specimens. Skin % tissue composition, measurement of the epidermis, dermis, sebaceous gland and hair follicle size, and skin NMR peaks were signatures of skin type. The image processing determined the dimensionality of skin tissue components and skin typing. The ex vivo MRI images and histopathology of the skin may be used to measure the skin structure and skin NMR peaks with image processing may be a tool for determining skin typing and skin composition.

Skin age testing criteria: characterization of human skin structures by 500 MHz MRI multiple contrast and image processing

NASA Astrophysics Data System (ADS)

Sharma, Rakesh

2010-07-01

Ex vivo magnetic resonance microimaging (MRM) image characteristics are reported in human skin samples in different age groups. Human excised skin samples were imaged using a custom coil placed inside a 500 MHz NMR imager for high-resolution microimaging. Skin MRI images were processed for characterization of different skin structures. Contiguous cross-sectional T1-weighted 3D spin echo MRI, T2-weighted 3D spin echo MRI and proton density images were compared with skin histopathology and NMR peaks. In all skin specimens, epidermis and dermis thickening and hair follicle size were measured using MRM. Optimized parameters TE and TR and multicontrast enhancement generated better MRI visibility of different skin components. Within high MR signal regions near to the custom coil, MRI images with short echo time were comparable with digitized histological sections for skin structures of the epidermis, dermis and hair follicles in 6 (67%) of the nine specimens. Skin % tissue composition, measurement of the epidermis, dermis, sebaceous gland and hair follicle size, and skin NMR peaks were signatures of skin type. The image processing determined the dimensionality of skin tissue components and skin typing. The ex vivo MRI images and histopathology of the skin may be used to measure the skin structure and skin NMR peaks with image processing may be a tool for determining skin typing and skin composition.

Influence of ultrasound or halogen light on microleakage and hardness of enamel adjacent to glass ionomer cement.

PubMed

Guglielmi, Camila Almeida Brandão; Mohana, Anice; Hesse, Daniela; Lenzi, Tathiane Larissa; Bonini, Gabriela Cunha; Raggio, Daniela Prócida

2012-03-01

The use of external sources of energy may accelerate the setting rate of glass ionomer cements (GICs) allowing better initial mechanical properties. To investigate the influence of ultrasound and halogen light on the microleakage and hardness of enamel adjacent to GIC restorations, after artificial caries challenge. Cavities were prepared in 60 primary canines, restored with GIC, and randomly distributed into three groups: control group (CG), light group (LG) - irradiation with a halogen light-curing unit for 60s, and ultrasonic group (UG) - application of ultrasonic scaler device for 15s. All specimens were then submitted to a cariogenic challenge in a pH cycling model. Half of sample in each group were immersed in methylene blue for 4h and sectioned for dye penetration analysis. The remaining specimens were submitted to Knoop cross-sectional microhardness assessments, and mineral changes were calculated for adjacent enamel. Data were compared using Kruskal-Wallis test and two-way ANOVA with 5% significance. Higher dye penetration was observed for the UG (P<0.01). No significant mineral changes were observed between groups (P=0.844). The use of halogen light-curing unit does not seem to interfere with the properties of GICs, whereas the use of ultrasound can affect its marginal sealing. © 2011 The Authors. International Journal of Paediatric Dentistry © 2011 BSPD, IAPD and Blackwell Publishing Ltd.

10 CFR 26.97 - Conducting an initial test for alcohol using a specimen of oral fluids.

Code of Federal Regulations, 2014 CFR

2014-01-01

... 10 Energy 1 2014-01-01 2014-01-01 false Conducting an initial test for alcohol using a specimen of oral fluids. 26.97 Section 26.97 Energy NUCLEAR REGULATORY COMMISSION FITNESS FOR DUTY PROGRAMS Collecting Specimens for Testing § 26.97 Conducting an initial test for alcohol using a specimen of oral...

10 CFR 26.97 - Conducting an initial test for alcohol using a specimen of oral fluids.

Code of Federal Regulations, 2012 CFR

2012-01-01

... 10 Energy 1 2012-01-01 2012-01-01 false Conducting an initial test for alcohol using a specimen of oral fluids. 26.97 Section 26.97 Energy NUCLEAR REGULATORY COMMISSION FITNESS FOR DUTY PROGRAMS Collecting Specimens for Testing § 26.97 Conducting an initial test for alcohol using a specimen of oral...

10 CFR 26.97 - Conducting an initial test for alcohol using a specimen of oral fluids.

Code of Federal Regulations, 2013 CFR

2013-01-01

... 10 Energy 1 2013-01-01 2013-01-01 false Conducting an initial test for alcohol using a specimen of oral fluids. 26.97 Section 26.97 Energy NUCLEAR REGULATORY COMMISSION FITNESS FOR DUTY PROGRAMS Collecting Specimens for Testing § 26.97 Conducting an initial test for alcohol using a specimen of oral...

10 CFR 26.97 - Conducting an initial test for alcohol using a specimen of oral fluids.

Code of Federal Regulations, 2011 CFR

2011-01-01

... 10 Energy 1 2011-01-01 2011-01-01 false Conducting an initial test for alcohol using a specimen of oral fluids. 26.97 Section 26.97 Energy NUCLEAR REGULATORY COMMISSION FITNESS FOR DUTY PROGRAMS Collecting Specimens for Testing § 26.97 Conducting an initial test for alcohol using a specimen of oral...

10 CFR 26.97 - Conducting an initial test for alcohol using a specimen of oral fluids.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 10 Energy 1 2010-01-01 2010-01-01 false Conducting an initial test for alcohol using a specimen of oral fluids. 26.97 Section 26.97 Energy NUCLEAR REGULATORY COMMISSION FITNESS FOR DUTY PROGRAMS Collecting Specimens for Testing § 26.97 Conducting an initial test for alcohol using a specimen of oral...

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

Gertz, M.A.; Brown, M.L.; Hauser, M.F.

Thirty-four patients with amyloidosis proved by biopsy specimen were studied using technetium Tc 99m pyrophosphate scintigraphy to assess its utility in the diagnosis of amyloid heart involvement. Of 14 patients studied retrospectively, only three had intense uptake judged to be diagnostic of cardiac amyloidosis. In a prospective analysis of 20 patients with amyloidosis, all of whom had evidence of cardiac involvement by two-dimensional echocardiography, 17 had abnormal scans. Fourteen of the 17 scans had only 1+ or 2+ uptake, a finding that also was present in 15 of the 20 control patients (without amyloid heart disease). Only three of themore » 20 patients with cardiac amyloidosis had intense uptake that was considered unequivocal and diagnostic of amyloidosis. Of the five patients with biopsy specimen proof of endomyocardial amyloidosis, only one had intense uptake and one had no uptake. When intense uptake of technetium Tc 99m pyrophosphate is found in the heart of a patient, amyloidosis is highly likely. The technique, however, is not sufficiently sensitive to warrant routine screening of patients with amyloidosis or cardiomyopathies. Cross-sectional echocardiography is superior to pyrophosphate scintigraphy for recognition of cardiac amyloidosis.« less

Effect of cooling rates on the structure, density and micro-indentation behavior of the Fe, Co-based bulk metallic glass

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

Lesz, Sabina, E-mail: sabina.lesz@polsl.pl

The experiments demonstrate that ductility of the samples of bulk metallic glass (BMG) with the same chemical composition increased with decreasing sample size. It is shown that microhardness and density increases with decreasing the cooling rate. The fracture morphology of rods after compressive fracture were different on the cross section. Two characteristic features of the compressive fracture morphologies of metallic glasses (MGs) were observed in samples: smooth region and the vein pattern. Many parallel shear bands were observed on the deformed specimen with ϕ = 2 mm in diameter. The results provide more understanding on the relationship among the coolingmore » rate, structure and micro-indentation behavior of the Fe-Co-based BMGs. - Highlights: •Fracture morphology and micro-indentation behavior is studied. •The smaller BMG sample exhibits the larger plasticity. •Microhardness and density increase with decreasing the cooling rate. •Formation of shear bands has been reported in deformed specimens. •Structure and mechanical properties of BMGs can be controlled by the cooling rate.« less

Hydrogen embrittlement of work-hardened Ni-Ti alloy in fluoride solutions.

PubMed

Yokoyama, Ken'ichi; Kaneko, Kazuyuki; Ogawa, Toshio; Moriyama, Keiji; Asaoka, Kenzo; Sakai, Jun'ichi

2005-01-01

Hydrogen embrittlement of work-hardened Ni-Ti alloy has been examined in acidulated phosphate fluoride (APF) solutions. Upon immersion in a 2.0% APF solution with a pH of 5.0, tensile strength decreased markedly with immersion time. Moreover, the fracture mode changed from ductile to brittle due to brittle layer formation at the peripheral part of the cross section of the specimen. The amount of absorbed hydrogen increased linearly with immersion time, and it reached above 5000 mass ppm after 24 h. The hydrogen desorption temperature of the immersed specimens shifted from 450 degrees C to a lower temperature with immersion time. As the amount of absorbed hydrogen was larger than 500 mass ppm, the degradation of mechanical properties was recognized. Although the tensile properties and fracture mode scarcely change in a 0.2% APF solution, the slight reduction in hardness and hydrogen absorption of several hundreds mass ppm were observed. The results of the present study imply that work-hardened Ni-Ti alloy is less sensitive to hydrogen embrittlement compared with Ni-Ti superelastic alloy. Copyright 2004 Elsevier Ltd.

Modeling and characterization of through-the-thickness properties of 3D woven composites

NASA Technical Reports Server (NTRS)

Hartranft, Dru; Pravizi-Majidi, Azar; Chou, Tsu-Wei

1995-01-01

The through-the-thickness properties of three-dimensionally (3D) woven carbon/epoxy composites have been studied. The investigation aimed at the evaluation and development of test methodologies for the property characterization in the thickness direction, and the establishment of fiber architectures were studied: layer-to-layer Angle Interlock, through-the-thickness Orthogonal woven preform with surface pile was also designed and manufactured for the fabrication of tensile test coupons with integrated grips. All the preforms were infiltrated by the resin transfer molding technique. The microstructures of the composites were characterized along the warp and fill (weft) directions to determine the degree of yarn undulations, yarn cross-sectional shapes, and microstructural dimensions. These parameters were correlated to the fiber architecture. Specimens were designed and tested for the direct measurement of the through-the-thickness tensile, compressive and shear properties of the composites. Design optimization was conducted through the analysis of the stress fields within the specimen coupled with experimental verification. The experimentally-derived elastic properties in the thickness direction compared well with analytical predictions obtained from a volume averaging model.

The morphological characterization of the forewing of the Manduca sexta species for the application of biomimetic flapping wing micro air vehicles.

PubMed

O'Hara, R P; Palazotto, A N

2012-12-01

To properly model the structural dynamics of the forewing of the Manduca sexta species, it is critical that the material and structural properties of the biological specimen be understood. This paper presents the results of a morphological study that has been conducted to identify the material and structural properties of a sample of male and female Manduca sexta specimens. The average mass, area, shape, size and camber of the wing were evaluated using novel measurement techniques. Further emphasis is placed on studying the critical substructures of the wing: venation and membrane. The venation cross section is measured using detailed pathological techniques over the entire venation of the wing. The elastic modulus of the leading edge veins is experimentally determined using advanced non-contact structural dynamic techniques. The membrane elastic modulus is randomly sampled over the entire wing to determine global material properties for the membrane using nanoindentation. The data gathered from this morphological study form the basis for the replication of future finite element structural models and engineered biomimetic wings for use with flapping wing micro air vehicles.

Experimental Investigation of Multi-mode Fiber Laser Cutting of Cement Mortar.

PubMed

Lee, Dongkyoung; Pyo, Sukhoon

2018-02-10

This study successfully applied multi-mode laser cutting with the variation of the laser cutting speed to cement mortar for the first time. The effects of the amount of silica sand in the cement mortar on laser cutting are tested and analyzed. The kerf width and penetration depth of the specimens after laser cutting are investigated. As the laser cutting speed increases, the penetration depth decreases for both cement paste and cement mortar, whereas the kerf width becomes saturated and increases, respectively, for cement paste and cement mortar. Cross sections of the specimens are compared with illustrations. Top-view images of the cement mortar with indicators of the physical characteristics, such as re-solidification, burning, and cracks are examined, and the possible causes of these characteristics are explained. The optical absorption rates of cement-based materials are quantified at wide ranges of wavelength to compare the absorption rates in accordance with the materials compositions. The chemical composition variation before and after laser cutting is also compared by EDX (Energy Dispersive X-Ray) analysis. In addition to these observations, material removal mechanisms for cement mortar are proposed.

Experimental Investigation of Multi-mode Fiber Laser Cutting of Cement Mortar

PubMed Central

2018-01-01

This study successfully applied multi-mode laser cutting with the variation of the laser cutting speed to cement mortar for the first time. The effects of the amount of silica sand in the cement mortar on laser cutting are tested and analyzed. The kerf width and penetration depth of the specimens after laser cutting are investigated. As the laser cutting speed increases, the penetration depth decreases for both cement paste and cement mortar, whereas the kerf width becomes saturated and increases, respectively, for cement paste and cement mortar. Cross sections of the specimens are compared with illustrations. Top-view images of the cement mortar with indicators of the physical characteristics, such as re-solidification, burning, and cracks are examined, and the possible causes of these characteristics are explained. The optical absorption rates of cement-based materials are quantified at wide ranges of wavelength to compare the absorption rates in accordance with the materials compositions. The chemical composition variation before and after laser cutting is also compared by EDX (Energy Dispersive X-Ray) analysis. In addition to these observations, material removal mechanisms for cement mortar are proposed. PMID:29439431

A hyperspectral X-ray computed tomography system for enhanced material identification

NASA Astrophysics Data System (ADS)

Wu, Xiaomei; Wang, Qian; Ma, Jinlei; Zhang, Wei; Li, Po; Fang, Zheng

2017-08-01

X-ray computed tomography (CT) can distinguish different materials according to their absorption characteristics. The hyperspectral X-ray CT (HXCT) system proposed in the present work reconstructs each voxel according to its X-ray absorption spectral characteristics. In contrast to a dual-energy or multi-energy CT system, HXCT employs cadmium telluride (CdTe) as the x-ray detector, which provides higher spectral resolution and separate spectral lines according to the material's photon-counter working principle. In this paper, a specimen containing ten different polymer materials randomly arranged was adopted for material identification by HXCT. The filtered back-projection algorithm was applied for image and spectral reconstruction. The first step was to sort the individual material components of the specimen according to their cross-sectional image intensity. The second step was to classify materials with similar intensities according to their reconstructed spectral characteristics. The results demonstrated the feasibility of the proposed material identification process and indicated that the proposed HXCT system has good prospects for a wide range of biomedical and industrial nondestructive testing applications.

The effect of thermal cycling to 1100 C on the alpha /Mo/ phase in directionally solidified gamma/gamma-prime-alpha alloys

NASA Technical Reports Server (NTRS)

Harf, F. H.

1981-01-01

Specimens of gamma/gamma-prime-alpha (Mo) eutectic alloy were thermally cycled or isothermally exposed at temperatures of 1075 to 1100 C. Transmission electron microscopy examination of cycled specimens indicated that even an exposure of 10 minutes effected noticeable changes in the shape of the alpha phase, and that the changes were cumulative as more cycles were added. The cross sections of fine, smooth fibers changed from rectangles to octagons, while lamellae and irregular shapes spheroidized. These effects are attributed to the differences in thermal expansion coefficients between the alpha phase and the gamma/gamma-prime matrix, and to the higher diffusion rates prevailing at elevated temperatures. Where the configuration of the alpha phase is a simple shape, such as a fiber, increasing the temperature eventually brings about a stress free interface between the alpha phase and the matrix by differential thermal expansion. Where the shape of the alpha phase is more complex, a stressed interface persists to higher temperatures where diffusion produces the more drastic morphological changes.

Study of mechanical joint strength of aluminum alloy 7075-T6 and dual phase steel 980 welded by friction bit joining and weld-bonding under corrosion medium

DOE PAGES

Lim, Yong Chae; Squires, Lile; Pan, Tsung-Yu; ...

2014-12-30

We have employed a unique solid-sate joining process, called friction bit joining (FBJ), to spot weld aluminum alloy (AA) 7075-T6 and dual phase (DP) 980 steel. Static joint strength was studied in the lap shear tension configuration. In addition, weld-bonding (adhesive + FBJ) joints were studied in order to evaluate the ability of adhesive to mitigate the impact of corrosion on joint properties. Accelerated laboratory cyclic corrosion tests were carried out for both FBJ only and weld-bonding joints. Furthermore, the FBJ only joints that emerged from corrosion testing had lap shear failure loads that were significantly lower than freshly preparedmore » joints. However, weld-bonding specimens retained more than 80% of the lap shear failure load of the freshly prepared weld-bonding specimens. Moreover, examination of joint cross sections confirmed that the presence of adhesive in the weld-bonding joints mitigated the effect of the corrosion environment, compared to FBJ only joints.« less

Analysis of Stress in Steel and Concrete in Cfst Push-Out Test Samples

NASA Astrophysics Data System (ADS)

Grzeszykowski, Bartosz; Szadkowska, Magdalena; Szmigiera, Elżbieta

2017-09-01

The paper presents the analysis of stress in steel and concrete in CFST composite elements subjected to push-out tests. Two analytical models of stress distribution are presented. The bond at the interface between steel and concrete in the initial phase of the push-out test is provided by the adhesion. Until the force reach a certain value, the slip between both materials does not occur or it is negligibly small, what ensures full composite action of the specimen. In the first analytical model the full bond between both materials was assumed. This model allows to estimate value of the force for which the local loss of adhesion in given cross section begins. In the second model it was assumed that the bond stress distribution is constant along the shear transfer length of the specimen. Based on that the formulas for triangle distribution of stress in steel and concrete for the maximum push-out force were derived and compared with the experimental results. Both models can be used to better understand the mechanisms of interaction between steel and concrete in composite steel-concrete columns.

Comparison of estrogen receptor results from pathology reports with results from central laboratory testing.

PubMed

Collins, Laura C; Marotti, Jonathan D; Baer, Heather J; Tamimi, Rulla M

2008-02-06

We compared estrogen receptor (ER) assay results abstracted from pathology reports with ER results determined on the same specimens by a central laboratory with an immunohistochemical assay. Paraffin sections were cut from tissue microarrays containing 3093 breast cancer specimens from women enrolled in the Nurses' Health Study, 1851 of which had both pathology reports and tissue available for central laboratory testing. All sections were immunostained for ER at the same time. The original assays were biochemical for 1512 (81.7%) of the 1851 specimens, immunohistochemical for 336 (18.2%), and immunofluorescent for three (0.2%). ER results from pathology reports and repeat central laboratory testing were in agreement for 87.3% of specimens (1615 of the 1851 specimens; kappa statistic = 0.64, P < .001). When the comparison was restricted to the specimens for which the ER assays were originally performed by immunohistochemistry, the agreement rate increased to 92.3% of specimens (310 of the 336 specimens; kappa statistic = 0.78, P < .001). Thus, ER assay results from pathology reports appear to be a reasonable alternative to central laboratory ER testing for large, population-based studies of patients with breast cancer.

Genetics of a sex-linked recessive red eye color mutant of the tarnished plant bug, Lygus lineolaris

USDA-ARS?s Scientific Manuscript database

An inbred colony of the tarnished plant bug, Lygus lineolaris (Palisot de Beauvois) (Miridae: Hemiptera), was observed to contain specimens with abnormal traits including red eyes, deformed antennae, and deformed legs. These specimens were isolated and back crossed to create stable phenotypic strain...

Microstructural and micromechanical characterization of IN718 theta shaped specimens built with electron beam melting

DOE PAGES

Cakmak, Ercan; Kirka, Michael M.; Watkins, Thomas R.; ...

2016-02-23

Theta-shaped specimens were additively manufactured out of Inconel 718 powders using an electron beam melting technique, as a model complex load bearing structure. We employed two different build strategies; producing two sets of specimens. Microstructural and micro-mechanical characterizations were performed using electron back-scatter, synchrotron x-ray and in-situ neutron diffraction techniques. In particular, the cross-members of the specimens were the focus of the synchrotron x-ray and in-situ neutron diffraction measurements. The build strategies employed resulted in the formation of distinct microstructures and crystallographic textures, signifying the importance of build-parameter manipulation for microstructural optimization. Large strain anisotropy of the different lattice planesmore » was observed during in-situ loading. Texture was concluded to have a distinct effect upon both the axial and transverse strain responses of the cross-members. In particular, the (200), (220) and (420) transverse lattice strains all showed unexpected overlapping trends in both builds. This was related to the strong {200} textures along the build/loading direction, providing agreement between the experimental and calculated results.« less

Fracture of Composite Compact Tension Specimens

DTIC Science & Technology

1975-01-01

E: lb/in.; X 10* M.: Fiber Volume, % 1002 S- glass /epoxy Unidirectional Crossply 6.9 4.7 2.3 4.7 1.0 1.1 0.28 0.14 55 MOD 1-5208...configuration used in most of the fracture experiments is shown in Fig. 1. In unidirectional S- glass /epoxy specimens the fiber direction with respect to...conducted only with 0° or 90° fiber orientation. Cross-ply specimens of both S- glass and graphite were tested with the outer plies oriented at 0°, 45

Breast Cancer Research at NASA

NASA Technical Reports Server (NTRS)

1998-01-01

Human primary breast tumor cells after 56 days of culture in a NASA Bioreactor. A cross-section of a construct, grown from surgical specimens of brease cancer, stained for microscopic examination, reveals areas of tumor cells dispersed throughout the non-epithelial cell background. The arrow denotes the foci of breast cancer cells. NASA's Marshall Space Flight Center (MSFC) is sponsoring research with Bioreactors, rotating wall vessels designed to grow tissue samples in space, to understand how breast cancer works. This ground-based work studies the growth and assembly of human mammary epithelial cell (HMEC) from breast cancer susceptible tissue. Radiation can make the cells cancerous, thus allowing better comparisons of healthy vs. tunorous tissue. Credit: Dr. Jearne Becker, University of South Florida

Behaviour of square FRP-Confined High-Strength Concrete Columns under Eccentric Compression

NASA Astrophysics Data System (ADS)

Fallah Pour, Ali; Gholampour, Aliakbar; Zheng, Junai; Ozbakkaloglu, Togay

2018-01-01

This paper presents the results of an experimental study on the effect of load eccentricity on the axial compressive behaviour of carbon fibre-reinforced polymer (CFRP)- confined high-strength concrete (HSC) columns with a square cross-section. The axial loading was applied to the specimens at six different load eccentricities ranging from zero to 50 mm. The results show that the load eccentricity significantly influences the axial load-displacement and axial stress-strain behaviour of FRP-confined HSC. Increasing the load eccentricity leads to an increase in the ultimate axial strain but a decrease in the ultimate axial stress and second branch slope of the axial stress-strain curve.

MORPH-II, a software package for the analysis of scanning-electron-micrograph images for the assessment of the fractal dimension of exposed stone surfaces

USGS Publications Warehouse

Mossotti, Victor G.; Eldeeb, A. Raouf

2000-01-01

Turcotte, 1997, and Barton and La Pointe, 1995, have identified many potential uses for the fractal dimension in physicochemical models of surface properties. The image-analysis program described in this report is an extension of the program set MORPH-I (Mossotti and others, 1998), which provided the fractal analysis of electron-microscope images of pore profiles (Mossotti and Eldeeb, 1992). MORPH-II, an integration of the modified kernel of the program MORPH-I with image calibration and editing facilities, was designed to measure the fractal dimension of the exposed surfaces of stone specimens as imaged in cross section in an electron microscope.

Microgravity

NASA Image and Video Library

1998-10-10

Human primary breast tumor cells after 56 days of culture in a NASA Bioreactor. A cross-section of a construct, grown from surgical specimens of brease cancer, stained for microscopic examination, reveals areas of tumor cells dispersed throughout the non-epithelial cell background. The arrow denotes the foci of breast cancer cells. NASA's Marshall Space Flight Center (MSFC) is sponsoring research with Bioreactors, rotating wall vessels designed to grow tissue samples in space, to understand how breast cancer works. This ground-based work studies the growth and assembly of human mammary epithelial cell (HMEC) from breast cancer susceptible tissue. Radiation can make the cells cancerous, thus allowing better comparisons of healthy vs. tunorous tissue. Credit: Dr. Jearne Becker, University of South Florida

Development of a multi-cycle shear-compression testing for the modeling of severe plastic deformation

NASA Astrophysics Data System (ADS)

Pesin, A.; Pustovoytov, D.; Lokotunina, N.

2017-12-01

The mechanism of severe plastic deformation comes from very significant shear strain. Shear-compression testing of materials is complicated by the fact that a state of large equivalent strain with dominant shear strain is not easily achievable. This paper presents the novel technique of laboratory simulation of severe plastic deformation by multi-cycle shear-compression testing at room temperature with equivalent strain e=1…5. The specimen consisted of a parallelepiped having an inclined gauge section created by two diametrically opposed semi-circular slots which were machined at 45°. Height of the specimen was 50 mm, section dimensions were 25×25 mm, gauge thickness was 5.0 mm and gauge width was 6.0 mm. The specimen provided dominant shear strain in an inclined gauge-section. The level of shear strain and equivalent strain was controlled through adjustment of the height reduction of the specimen, load application direction and number of cycles of shear-compression. Aluminium alloy Al-6.2Mg-0.7Mn was used as a material for specimen. FE simulation and analysis of the stress-strain state were performed. The microstructure of the specimen after multi-cycle shear-compression testing with equivalent strain e=1…5 was examined by optical and scanning electron microscope.

Computer aided three-dimensional reconstruction and modeling of the pelvis, by using plastinated cross sections, as a powerful tool for morphological investigations.

PubMed

Sora, Mircea-Constantin; Jilavu, Radu; Matusz, Petru

2012-10-01

The aim of this study was to describe a method of developing a computerized model of the human female pelvis using plastinated slices. Computerized reconstruction of anatomical structures is becoming very useful for developing anatomical teaching, research modules and animations. Although databases consisting of serial sections derived from frozen cadaver material exist, plastination represents an alternative method for developing anatomical data useful for computerized reconstruction. A slice anatomy study, using plastinated transparent pelvis cross sections, was performed to obtain a 3D reconstruction. One female human pelvis used for this study, first plastinated as a block, then sliced into thin slices and in the end subjected to 3D computerized reconstruction using WinSURF modeling system (SURFdriver Software). To facilitate the understanding of the complex pelvic floor anatomy on sectional images obtained through MR imaging, and to make the representation more vivid, a female pelvis computer-aided 3D model was created. Qualitative observations revealed that the morphological features of the model were consistent with those displayed by typical cadaveric specimens. The quality of the reconstructed images appeared distinct, especially the spatial positions and complicated relationships of contiguous structures of the female pelvis. All reconstructed structures can be displayed in groups or as a whole and interactively rotated in 3D space. The utilization of plastinates for generating tissue sections is useful for 3D computerized modeling. The 3D model of the female pelvis presented in this paper provides a stereoscopic view to study the adjacent relationship and arrangement of respective pelvis sections. A better understanding of the pelvic floor anatomy is relevant to gynaecologists, radiologists, surgeons, urologists, physical therapists and all professionals who take care of women with pelvic floor dysfunction.

Damage Tolerant Design for Cold-Section Turbine Engine Disks

DTIC Science & Technology

1981-06-01

Ti-6Al-4V Disks ......... .. 59 28. FIOO 2nd-Stage Fan Disk Designs ........ ................ .. 61 29. Fan Disk Tangential Stress Profile... 61 30. Life-Limiting Features of Damage-Tolerant Disk .......... ... 62 31. Disk Life Limits .... ...................... 62 32. Life Test...Stress Rati• Model ..... .......... .. 113 61 . Thick-Section Center-Notched Specimen ....... ............. .. 116 62. Bolthole Specimen

Freckle Defect Formation near the Casting Interfaces of Directionally Solidified Superalloys

PubMed Central

Hong, Jianping; Ma, Dexin; Wang, Jun; Wang, Fu; Sun, Baode; Dong, Anping; Li, Fei; Bührig-Polaczek, Andreas

2016-01-01

Freckle defects usually appear on the surface of castings and industrial ingots during the directional solidification process and most of them are located near the interface between the shell mold and superalloys. Ceramic cores create more interfaces in the directionally solidified (DS) and single crystal (SX) hollow turbine blades. In order to investigate the location of freckle occurrence in superalloys, superalloy CM247 LC was directionally solidified in an industrial-sized Bridgman furnace. Instead of ceramic cores, Alumina tubes were used inside of the casting specimens. It was found that freckles occur not only on the casting external surfaces, but also appear near the internal interfaces between the ceramic core and superalloys. Meanwhile, the size, initial position, and area of freckle were investigated in various diameters of the specimens. The initial position of the freckle chain reduces when the diameter of the rods increase. Freckle area follows a linear relationship in various diameters and the average freckle fraction is 1.1% of cross sectional area of casting specimens. The flow of liquid metal near the interfaces was stronger than that in the interdendritic region in the mushy zone, and explained why freckle tends to occur on the outer or inner surfaces of castings. This new phenomenon suggests that freckles are more likely to occur on the outer or inner surfaces of the hollow turbine blades. PMID:28774050

Freckle Defect Formation near the Casting Interfaces of Directionally Solidified Superalloys.

PubMed

Hong, Jianping; Ma, Dexin; Wang, Jun; Wang, Fu; Sun, Baode; Dong, Anping; Li, Fei; Bührig-Polaczek, Andreas

2016-11-16

Freckle defects usually appear on the surface of castings and industrial ingots during the directional solidification process and most of them are located near the interface between the shell mold and superalloys. Ceramic cores create more interfaces in the directionally solidified (DS) and single crystal (SX) hollow turbine blades. In order to investigate the location of freckle occurrence in superalloys, superalloy CM247 LC was directionally solidified in an industrial-sized Bridgman furnace. Instead of ceramic cores, Alumina tubes were used inside of the casting specimens. It was found that freckles occur not only on the casting external surfaces, but also appear near the internal interfaces between the ceramic core and superalloys. Meanwhile, the size, initial position, and area of freckle were investigated in various diameters of the specimens. The initial position of the freckle chain reduces when the diameter of the rods increase. Freckle area follows a linear relationship in various diameters and the average freckle fraction is 1.1% of cross sectional area of casting specimens. The flow of liquid metal near the interfaces was stronger than that in the interdendritic region in the mushy zone, and explained why freckle tends to occur on the outer or inner surfaces of castings. This new phenomenon suggests that freckles are more likely to occur on the outer or inner surfaces of the hollow turbine blades.

Fatigue and failure responses of lead zirconate titanate multilayer actuator under unipolar high-field electric cycling

NASA Astrophysics Data System (ADS)

Zeng, Fan Wen; Wang, Hong; Lin, Hua-Tay

2013-07-01

Lead zirconate titanate (PZT) multilayer actuators with an interdigital electrode design were studied under high electric fields (3 and 6 kV/mm) in a unipolar cycling mode. A 100 Hz sine wave was used in cycling. Five specimens tested under 6 kV/mm failed from 3.8 × 105 to 7 × 105 cycles, whereas three other specimens tested under 3 kV/mm were found to be still functional after 108 cycles. Variations in piezoelectric and dielectric responses of the tested specimens were observed during the fatigue test, depending on the measuring and cycling conditions. Selected fatigued and damaged actuators were characterized using an impedance analyzer or small signal measurement. Furthermore, involved fatigue and failure mechanisms were investigated using scanning acoustic microscope and scanning electron microscope. The extensive cracks and porous regions were revealed across the PZT layers on the cross sections of a failed actuator. The results from this study have demonstrated that the high-field cycling can accelerate the fatigue of PZT stacks as long as the partial discharge is controlled. The small signal measurement can also be integrated into the large signal measurement to characterize the fatigue response of PZT stacks in a more comprehensive basis. The former can further serve as an experimental method to test and monitor the behavior of PZT stacks.

Gas levitator having fixed levitation node for containerless processing

NASA Technical Reports Server (NTRS)

Berge, L. H.; Oran, W. A.; Theiss, M. (Inventor)

1981-01-01

A method and apparatus is disclosed for levitating a specimen of material in a containerless environment at a stable nodal position independent of gravity. An elongated levitation tube has a contoured interior in the form of convergent section, constriction, and a divergent section in which the levitation node is created. A gas flow control means prevents separation of flow from the interior walls in the region of a specimen. The apparatus provides for levitating and heating the specimen simultaneously by combustion of a suitable gas mixture combined with an inert gas.

Specific identification of human papillomavirus type in cervical smears and paraffin sections by in situ hybridization with radioactive probes: a preliminary communication

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

Gupta, J.; Gendelman, H.E.; Naghashfar, Z.

1985-01-01

Cervical Papanicolaou smears and paraffin sections of biopsy specimens obtained from women attending dysplasia clinics were examined for viral DNA sequences by in situ hybridization technique using TVS-labeled cloned recombinant DNA probes of human papillomavirus (HPV) types 6, 11, and 16. These and one unrelated DNA probe complementary to measles virus RNA were labeled by nick translation using either one or two TVS-labeled nucleotides. Paraffin sections and cervical smears were collected on pretreated slides, hybridized with the probes under stringent or nonstringent conditions for 50 h, and autoradiographed. Additional cervical specimens from the same women were examined for the presencemore » of genus-specific papillomavirus capsid antigen by the immunoperoxidase technique. Preliminary results may be summarized as follows. The infecting virus could be identified in smears as well as in sections. Viral DNA sequences were detected only when there were condylomatous cells in the specimen and in only a proportion of the condylomatous cells. Even under stringent conditions, some specimens reacted with both HPV-6 and HPV-11. In some instances, the cells did not hybridize with any of the three probes even when duplicate specimens contained frankly condylomatous, capsid antigen-positive cells. In situ hybridization of Papanicolaou smears or of tissue sections is a practical method for diagnosis and follow-up of specific papillomavirus infection using routinely collected material.« less

FINAL ANALYTICAL RESULTS FROM THE EXAMINATION OF CORROSION ON SECTIONS OF CORROSION PROBE REMOVED FROM TANK 241-AN-107 ON 08/10/2006

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

DUNCAN JB; COOKE GA

2007-03-22

Tank Farms Operations removed an electrochemical noise probe from Tank 241-AN-107. In the field, the probe was cut into four sections, wrapped, and placed in a 55-gallon drum, This drum was delivered to the 222-S Laboratory. The 222 S Laboratory unpackaged the sections of the AN-107 electrochemical noise probe and examined the material for evidence of corrosion. Each of the four sections contained three C-ring and three bullet specimens. The specimens were examined for pitting corrosion, crevice corrosion, and stress corrosion cracking. No evidence of stress corrosion cracking was found in the stressed C-ring specimens. Minor pitting was evident onmore » some surfaces. Crevice corrosion was the dominant type of corrosion observed.« less

40 CFR 160.51 - Specimen and data storage facilities.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 40 Protection of Environment 23 2010-07-01 2010-07-01 false Specimen and data storage facilities. 160.51 Section 160.51 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) PESTICIDE PROGRAMS GOOD LABORATORY PRACTICE STANDARDS Facilities § 160.51 Specimen and data storage facilities. Space...

40 CFR 792.51 - Specimen and data storage facilities.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 40 Protection of Environment 31 2010-07-01 2010-07-01 true Specimen and data storage facilities. 792.51 Section 792.51 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) TOXIC SUBSTANCES CONTROL ACT (CONTINUED) GOOD LABORATORY PRACTICE STANDARDS Facilities § 792.51 Specimen and data...

Rapid Identification of Laboratory Contamination with Mycobacterium tuberculosis Using Variable Number Tandem Repeat Analysis

PubMed Central

Gascoyne-Binzi, Deborah M.; Barlow, Rachael E. L.; Frothingham, Richard; Robinson, Grant; Collyns, Timothy A.; Gelletlie, Ruth; Hawkey, Peter M.

2001-01-01

Compared with solid media, broth-based mycobacterial culture systems have increased sensitivity but also have higher false-positive rates due to cross-contamination. Systematic strain typing is rarely undertaken because the techniques are technically demanding and the data are difficult to organize. Variable number tandem repeat (VNTR) analysis by PCR is rapid and reproducible. The digital profile is easily manipulated in a database. We undertook a retrospective study of Mycobacterium tuberculosis isolates collected over an 18-month period following the introduction of the BACTEC MGIT 960 system. VNTR allele profiles were determined with early positive broth cultures and entered into a database with the specimen processing date and other specimen data. We found 36 distinct VNTR profiles in cultures from 144 patients. Three common VNTR profiles accounted for 45% of true-positive cases. By combining VNTR results with specimen data, we identified nine cross-contamination incidents, six of which were previously unsuspected. These nine incidents resulted in 34 false-positive cultures for 29 patients. False-positive cultures were identified for three patients who had previously been culture positive for tuberculosis and were receiving treatment. Identification of cross-contamination incidents requires careful documentation of specimen data and good communication between clinical and laboratory staff. Automated broth culture systems should be supplemented with molecular analysis to identify cross-contamination events. VNTR analysis is reproducible and provides timely results when applied to early positive broth cultures. This method should ensure that patients are not placed on unnecessary tuberculosis therapy or that cases are not falsely identified as treatment failures. In addition, areas where existing procedures may be improved can be identified. PMID:11136751

49 CFR 40.171 - How does an employee request a test of a split specimen?

Code of Federal Regulations, 2013 CFR

2013-10-01

... 49 Transportation 1 2013-10-01 2013-10-01 false How does an employee request a test of a split specimen? 40.171 Section 40.171 Transportation Office of the Secretary of Transportation PROCEDURES FOR TRANSPORTATION WORKPLACE DRUG AND ALCOHOL TESTING PROGRAMS Split Specimen Tests § 40.171 How does an employee request a test of a split specimen? (a...

Edgeless composite laminate specimen for static and fatigue testing

NASA Technical Reports Server (NTRS)

Liber, T.; Daniel, I. M.

1978-01-01

The influence of edge effects on the tensile properties of angle-ply laminate composites can be eliminated by using edgeless (round tubular) specimens. However, uniaxial tests with such specimens, static and fatigue, have been generally unsuccessful because of the differential Poisson effect between the test section and the grips. An edgeless cylindrical specimen, developed to circumvent these difficulties, is examined in the present paper. It is a flattened tube consisting of two flat sides connected by curved sections. It can be handled much like the standard flat coupon. The flat ends of the specimen are provided with crossplied fiberglass gripping tabs, the same as used for flat test coupons. As part of the tabbing, the hollow ends must be plugged with inserts to prevent crushing of the ends. A special insert design was developed to minimize detrimental Poisson effects ordinarily introduced by inserts.

Effects of blood contamination on microtensile bond strength to dentin of three self-etch adhesives.

PubMed

Chang, Seok Woo; Cho, Byeong Hoon; Lim, Ran Yeob; Kyung, Seung Hyun; Park, Dong Sung; Oh, Tae Seok; Yoo, Hyun Mi

2010-01-01

This study evaluated the effects of blood contamination and decontamination methods during different steps of bonding procedures on the microtensile bond strength of two-step self-etch adhesives to dentin. Sixty extracted human molars were ground flat to expose occlusal dentin. The 60 molars were randomly assigned to three groups, each treated with a different two-step self-etch adhesive: Clearfil SE Bond, AdheSE and Tyrian SPE. In turn, these groups were subdivided into five subgroups (n = 20), each treated using different experimental conditions as follows: control group-no contamination; contamination group 1-CG1: primer application/ contamination/primer re-application; contamination group 2-CG2: primer application/contamination/wash/dry/primer re-application; contamination group 3-CG3: primer application/adhesive application/light curing/contamination/ adhesive re-application/light curing; contamina- tion group 4-CG4: primer application/adhesive application/light curing/contamination/wash/ dry/adhesive re-application/light curing. Composite buildup was performed using Z250. After 24 hours of storage in distilled water at 37 degrees C, the bonded specimens were trimmed to an hourglass shape and serially sectioned into slabs with 0.6 mm2 cross-sectional areas. Microtensile bond strengths (MTBS) were assessed for each specimen using a universal testing machine. The data were analyzed by two-way ANOVA followed by a post hoc LSD test. SEM evaluations of the fracture modes were also performed. The contaminated specimens showed lower bond strengths than specimens in the control group (p < 0.05), with the exception of CG1 in the Clearfil SE group and CG2 and CG3 in the Tyrian SPE group. Among the three self-etch adhesives, the Tyrian SPE group exhibited a significantly lower average MTBS compared to the Clearfil SE Bond and AdheSE (p < 0.05) groups. Based on the results of the current study, it was found that blood contamination reduced the MTBS of all three self-etch adhesives to dentin, and water-rinsing was unable to overcome the effects of blood contamination.

43 CFR 15.9 - Collection of scientific specimens.

Code of Federal Regulations, 2012 CFR

2012-10-01

... 43 Public Lands: Interior 1 2012-10-01 2011-10-01 true Collection of scientific specimens. 15.9 Section 15.9 Public Lands: Interior Office of the Secretary of the Interior KEY LARGO CORAL REEF PRESERVE § 15.9 Collection of scientific specimens. Collection of natural objects and marine life for...

43 CFR 15.9 - Collection of scientific specimens.

Code of Federal Regulations, 2013 CFR

2013-10-01

... 43 Public Lands: Interior 1 2013-10-01 2013-10-01 false Collection of scientific specimens. 15.9 Section 15.9 Public Lands: Interior Office of the Secretary of the Interior KEY LARGO CORAL REEF PRESERVE § 15.9 Collection of scientific specimens. Collection of natural objects and marine life for...

43 CFR 15.9 - Collection of scientific specimens.

Code of Federal Regulations, 2014 CFR

2014-10-01

... 43 Public Lands: Interior 1 2014-10-01 2014-10-01 false Collection of scientific specimens. 15.9 Section 15.9 Public Lands: Interior Office of the Secretary of the Interior KEY LARGO CORAL REEF PRESERVE § 15.9 Collection of scientific specimens. Collection of natural objects and marine life for...

43 CFR 15.9 - Collection of scientific specimens.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 43 Public Lands: Interior 1 2010-10-01 2010-10-01 false Collection of scientific specimens. 15.9 Section 15.9 Public Lands: Interior Office of the Secretary of the Interior KEY LARGO CORAL REEF PRESERVE § 15.9 Collection of scientific specimens. Collection of natural objects and marine life for...

43 CFR 15.9 - Collection of scientific specimens.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 43 Public Lands: Interior 1 2011-10-01 2011-10-01 false Collection of scientific specimens. 15.9 Section 15.9 Public Lands: Interior Office of the Secretary of the Interior KEY LARGO CORAL REEF PRESERVE § 15.9 Collection of scientific specimens. Collection of natural objects and marine life for...

10 CFR 26.109 - Urine specimen quantity.

Code of Federal Regulations, 2014 CFR

2014-01-01

... 10 Energy 1 2014-01-01 2014-01-01 false Urine specimen quantity. 26.109 Section 26.109 Energy NUCLEAR REGULATORY COMMISSION FITNESS FOR DUTY PROGRAMS Collecting Specimens for Testing § 26.109 Urine... shall encourage the donor to drink a reasonable amount of liquid (normally, 8 ounces of water every 30...

10 CFR 26.109 - Urine specimen quantity.

Code of Federal Regulations, 2013 CFR

2013-01-01

... 10 Energy 1 2013-01-01 2013-01-01 false Urine specimen quantity. 26.109 Section 26.109 Energy NUCLEAR REGULATORY COMMISSION FITNESS FOR DUTY PROGRAMS Collecting Specimens for Testing § 26.109 Urine... shall encourage the donor to drink a reasonable amount of liquid (normally, 8 ounces of water every 30...

10 CFR 26.109 - Urine specimen quantity.

Code of Federal Regulations, 2012 CFR

2012-01-01

... 10 Energy 1 2012-01-01 2012-01-01 false Urine specimen quantity. 26.109 Section 26.109 Energy NUCLEAR REGULATORY COMMISSION FITNESS FOR DUTY PROGRAMS Collecting Specimens for Testing § 26.109 Urine... shall encourage the donor to drink a reasonable amount of liquid (normally, 8 ounces of water every 30...

10 CFR 26.129 - Assuring specimen security, chain of custody, and preservation.

Code of Federal Regulations, 2013 CFR

2013-01-01

... 10 Energy 1 2013-01-01 2013-01-01 false Assuring specimen security, chain of custody, and preservation. 26.129 Section 26.129 Energy NUCLEAR REGULATORY COMMISSION FITNESS FOR DUTY PROGRAMS Licensee Testing Facilities § 26.129 Assuring specimen security, chain of custody, and preservation. (a) Each...

10 CFR 26.129 - Assuring specimen security, chain of custody, and preservation.

Code of Federal Regulations, 2014 CFR

2014-01-01

... 10 Energy 1 2014-01-01 2014-01-01 false Assuring specimen security, chain of custody, and preservation. 26.129 Section 26.129 Energy NUCLEAR REGULATORY COMMISSION FITNESS FOR DUTY PROGRAMS Licensee Testing Facilities § 26.129 Assuring specimen security, chain of custody, and preservation. (a) Each...

10 CFR 26.129 - Assuring specimen security, chain of custody, and preservation.

Code of Federal Regulations, 2012 CFR

2012-01-01

... 10 Energy 1 2012-01-01 2012-01-01 false Assuring specimen security, chain of custody, and preservation. 26.129 Section 26.129 Energy NUCLEAR REGULATORY COMMISSION FITNESS FOR DUTY PROGRAMS Licensee Testing Facilities § 26.129 Assuring specimen security, chain of custody, and preservation. (a) Each...

10 CFR 707.12 - Specimen collection, handling and laboratory analysis for drug testing.

Code of Federal Regulations, 2011 CFR

2011-01-01

... drug testing. 707.12 Section 707.12 Energy DEPARTMENT OF ENERGY WORKPLACE SUBSTANCE ABUSE PROGRAMS AT DOE SITES Procedures § 707.12 Specimen collection, handling and laboratory analysis for drug testing... collection to final disposition of specimens, and testing laboratories shall use appropriate cutoff levels in...

10 CFR 707.12 - Specimen collection, handling and laboratory analysis for drug testing.

Code of Federal Regulations, 2010 CFR

2010-01-01

... drug testing. 707.12 Section 707.12 Energy DEPARTMENT OF ENERGY WORKPLACE SUBSTANCE ABUSE PROGRAMS AT DOE SITES Procedures § 707.12 Specimen collection, handling and laboratory analysis for drug testing... collection to final disposition of specimens, and testing laboratories shall use appropriate cutoff levels in...

10 CFR 707.12 - Specimen collection, handling and laboratory analysis for drug testing.

Code of Federal Regulations, 2014 CFR

2014-01-01

... drug testing. 707.12 Section 707.12 Energy DEPARTMENT OF ENERGY WORKPLACE SUBSTANCE ABUSE PROGRAMS AT DOE SITES Procedures § 707.12 Specimen collection, handling and laboratory analysis for drug testing... collection to final disposition of specimens, and testing laboratories shall use appropriate cutoff levels in...

10 CFR 707.12 - Specimen collection, handling and laboratory analysis for drug testing.

Code of Federal Regulations, 2012 CFR

2012-01-01

... drug testing. 707.12 Section 707.12 Energy DEPARTMENT OF ENERGY WORKPLACE SUBSTANCE ABUSE PROGRAMS AT DOE SITES Procedures § 707.12 Specimen collection, handling and laboratory analysis for drug testing... collection to final disposition of specimens, and testing laboratories shall use appropriate cutoff levels in...

10 CFR 707.12 - Specimen collection, handling and laboratory analysis for drug testing.

Code of Federal Regulations, 2013 CFR

2013-01-01

... drug testing. 707.12 Section 707.12 Energy DEPARTMENT OF ENERGY WORKPLACE SUBSTANCE ABUSE PROGRAMS AT DOE SITES Procedures § 707.12 Specimen collection, handling and laboratory analysis for drug testing... collection to final disposition of specimens, and testing laboratories shall use appropriate cutoff levels in...

10 CFR 26.129 - Assuring specimen security, chain of custody, and preservation.

Code of Federal Regulations, 2011 CFR

2011-01-01

... 10 Energy 1 2011-01-01 2011-01-01 false Assuring specimen security, chain of custody, and preservation. 26.129 Section 26.129 Energy NUCLEAR REGULATORY COMMISSION FITNESS FOR DUTY PROGRAMS Licensee Testing Facilities § 26.129 Assuring specimen security, chain of custody, and preservation. (a) Each...

10 CFR 26.129 - Assuring specimen security, chain of custody, and preservation.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 10 Energy 1 2010-01-01 2010-01-01 false Assuring specimen security, chain of custody, and preservation. 26.129 Section 26.129 Energy NUCLEAR REGULATORY COMMISSION FITNESS FOR DUTY PROGRAMS Licensee Testing Facilities § 26.129 Assuring specimen security, chain of custody, and preservation. (a) Each...

Full-field local displacement analysis of two-sided paperboard

Treesearch

J.M. Considine; D.W. Vahey

2007-01-01

This report describes a method to examine full-field displacements of both sides of paperboard during tensile testing. Analysis showed out-of-plane shear behavior near the failures zones. The method was reliably used to examine out-of-plane shear in double notch shear specimens. Differences in shear behavior of machine direction and cross-machine direction specimens...

Carotid Plaque Morphological Classification Compared With Biomechanical Cap Stress: Implications for a Magnetic Resonance Imaging-Based Assessment.

PubMed

Gijsen, Frank J H; Nieuwstadt, Harm A; Wentzel, Jolanda J; Verhagen, Hence J M; van der Lugt, Aad; van der Steen, Antonius F W

2015-08-01

Two approaches to target plaque vulnerability-a histopathologic classification scheme and a biomechanical analysis-were compared and the implications for noninvasive risk stratification of carotid plaques using magnetic resonance imaging were assessed. Seventy-five histological plaque cross sections were obtained from carotid endarterectomy specimens from 34 patients (>70% stenosis) and subjected to both a Virmani histopathologic classification (thin fibrous cap atheroma with <0.2-mm cap thickness, presumed vulnerable) and a peak cap stress computation (<140 kPa: presumed stable; >300 kPa: presumed vulnerable). To demonstrate the implications for noninvasive plaque assessment, numeric simulations of a typical carotid magnetic resonance imaging protocol were performed (0.62×0.62 mm(2) in-plane acquired voxel size) and used to obtain the magnetic resonance imaging-based peak cap stress. Peak cap stress was generally associated with histological classification. However, only 16 of 25 plaque cross sections could be labeled as high-risk (peak cap stress>300 kPa and classified as a thin fibrous cap atheroma). Twenty-eight of 50 plaque cross sections could be labeled as low-risk (a peak cap stress<140 kPa and not a thin fibrous cap atheroma), leading to a κ=0.39. 31 plaques (41%) had a disagreement between both classifications. Because of the limited magnetic resonance imaging voxel size with regard to cap thickness, a noninvasive identification of only a group of low-risk, thick-cap plaques was reliable. Instead of trying to target only vulnerable plaques, a more reliable noninvasive identification of a select group of stable plaques with a thick cap and low stress might be a more fruitful approach to start reducing surgical interventions on carotid plaques. © 2015 American Heart Association, Inc.

Computed tomographic anatomy of the heads of blue-and-gold macaws (Ara ararauna), African grey parrots (Psittacus erithacus), and monk parakeets (Myiopsitta monachus).

PubMed

Veladiano, Irene A; Banzato, Tommaso; Bellini, Luca; Montani, Alessandro; Catania, Salvatore; Zotti, Alessandro

2016-12-01

OBJECTIVE To create an atlas of the normal CT anatomy of the head of blue-and-gold macaws (Ara ararauna), African grey parrots (Psittacus erithacus), and monk parakeets (Myiopsitta monachus). ANIMALS 3 blue-and-gold macaws, 5 African grey parrots, and 6 monk parakeets and cadavers of 4 adult blue-and-gold macaws, 4 adult African grey parrots, and 7 monk parakeets. PROCEDURES Contrast-enhanced CT imaging of the head of the live birds was performed with a 4-multidetector-row CT scanner. Cadaveric specimens were stored at -20°C until completely frozen, and each head was then sliced at 5-mm intervals to create reference cross sections. Frozen cross sections were cleaned with water and photographed on both sides. Anatomic structures within each head were identified with the aid of the available literature, labeled first on anatomic photographs, and then matched to and labeled on corresponding CT images. The best CT reconstruction filter, window width, and window level for obtaining diagnostic images of each structure were also identified. RESULTS Most of the clinically relevant structures of the head were identified in both the cross-sectional photographs and corresponding CT images. Optimal visibility of the bony structures was achieved via CT with a standard soft tissue filter and pulmonary window. The use of contrast medium allowed a thorough evaluation of the soft tissues. CONCLUSIONS AND CLINICAL RELEVANCE The labeled CT images and photographs of anatomic structures of the heads of common pet parrot species created in this study may be useful as an atlas to aid interpretation of images obtained with any imaging modality.

Technical Note: Method to correlate whole-specimen histopathology of radical prostatectomy with diagnostic MR imaging

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

McGrath, Deirdre M., E-mail: d.mcgrath@sheffield.ac.uk; Lee, Jenny; Foltz, Warren D.

Purpose: Validation of MRI-guided tumor boundary delineation for targeted prostate cancer therapy is achieved via correlation with gold-standard histopathology of radical prostatectomy specimens. Challenges to accurate correlation include matching the pathology sectioning plane with the in vivo imaging slice plane and correction for the deformation that occurs between in vivo imaging and histology. A methodology is presented for matching of the histological sectioning angle and position to the in vivo imaging slices. Methods: Patients (n = 4) with biochemical failure following external beam radiotherapy underwent diagnostic MRI to confirm localized recurrence of prostate cancer, followed by salvage radical prostatectomy. High-resolutionmore » 3-D MRI of the ex vivo specimens was acquired to determine the pathology sectioning angle that best matched the in vivo imaging slice plane, using matching anatomical features and implanted fiducials. A novel sectioning device was developed to guide sectioning at the correct angle, and to assist the insertion of reference dye marks to aid in histopathology reconstruction. Results: The percentage difference in the positioning of the urethra in the ex vivo pathology sections compared to the positioning in in vivo images was reduced from 34% to 7% through slicing at the best match angle. Reference dye marks were generated, which were visible in ex vivo imaging, in the tissue sections before and after processing, and in histology sections. Conclusions: The method achieved an almost fivefold reduction in the slice-matching error and is readily implementable in combination with standard MRI technology. The technique will be employed to generate datasets for correlation of whole-specimen prostate histopathology with in vivo diagnostic MRI using 3-D deformable registration, allowing assessment of the sensitivity and specificity of MRI parameters for prostate cancer. Although developed specifically for prostate, the method is readily adaptable to other types of whole tissue specimen, such as mastectomy or liver resection.« less

Inducement of tissue regeneration of harvested hamstring tendons in a rabbit model

PubMed Central

Soejima, T.; Murakami, H.; Noguchi, K.; Shiba, N.; Nagata, K.

2016-01-01

Objectives The objective of this study was to determine if the use of fascia lata as a tendon regeneration guide (placed into the tendon canal following harvesting the semitendinosus tendon) would improve the incidence of tissue regeneration and prevent fatty degeneration of the semitendinosus muscle. Materials and Methods Bilateral semitendinosus tendons were harvested from rabbits using a tendon stripper. On the inducing graft (IG) side, the tendon canal and semitendinosus tibial attachment site were connected by the fascia lata, which was harvested at the same width as the semitendinosus tendon. On the control side, no special procedures were performed. Two groups of six rabbits were killed at post-operative weeks 4 and 8, respectively. In addition, three healthy rabbits were killed to obtain normal tissue. We evaluated the incidence of tendon tissue regeneration, cross-sectional area of the regenerated tendon tissue and proportion of fatty tissue in the semitendinosus muscle. Results At post-operative week 8, the distal end of the regenerated tissue reached the vicinity of the tibial insertion on the control side in two of six specimens. On the IG side, the regenerated tissue maintained continuity with the tibial insertion in all specimens. The cross-sectional area of the IG side was significantly greater than that of the control side. The proportion of fatty tissue in the semitendinosus muscle on the IG side was comparable with that of the control side, but was significantly greater than that of the normal muscle. Conclusions Tendon tissue regenerated with the fascia lata graft was thicker than naturally occurring regenerated tissue. However, the proportion of fatty tissue in the semitendinosus muscle was greater than that of normal muscle. Cite this article: K. Tabuchi, T. Soejima, H. Murakami, K. Noguchi, N. Shiba, K. Nagata. Inducement of tissue regeneration of harvested hamstring tendons in a rabbit model. Bone Joint Res 2016;5:247–252. DOI: 10.1302/2046-3758.56.2000585. PMID:27340141

Microstructure and hot corrosion behavior of the Ni-based superalloy GH202 treated by laser shock processing

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

Cao, Jiangdong

The effects of laser shock processing on microstructure, the residual stress, and hot corrosion behavior of the Ni-based superalloy GH202 were investigated. The microstructures of GH202 before and after laser shock processing (LSP) were characterized by electron backscattered diffraction (EBSD) and transmission electron microscope (TEM). A large number of crystal defects (twins, dislocation arrays, and high dense tangles) were generated on the surface of GH202 treated with LSP. The cross-sectional compressive residual stress and micro-hardness of specimens treated by LSP were improved significantly. The corrosion kinetics of GH202 with or without LSP treatment at 800 °C and 900 °C weremore » investigated. Analysis by X-ray diffraction (XRD) revealed that the corrosion products mainly consist of Cr{sub 2}O{sub 3}, TiO{sub 2}, Al{sub 2}O{sub 3}, NiO, CrS, Ni{sub 3}S{sub 2}, and Na{sub 2}CrO{sub 4}. The surface and cross-section morphologies were observed by scanning electron microscope (SEM) combined with energy dispersive spectroscopy (EDS). The results confirmed that the crystal defects induced by LSP promotes the creation of diffusion paths for elements (Cr, Al, and Ti), allowing the formation of tiny homogeneous oxidation films in a very short time. Additionally, the spallation of oxidation film on the treated specimens was alleviated significantly. Overall, the hot corrosion resistance of Ni-based GH202 induced by LSP was improved in Na{sub 2}SO{sub 4} and NaCl molten salt from 800 °C to 900 °C. - Highlights: • Microstructure changes of GH202 before and after LSP were observed by EBSD and TEM. • The hardness and residual compressive stress after LSP were significantly increased. • The increased diffusion paths for elements helped to form oxidation films quickly. • Hot corrosion resistance of GH202 after LSP was significantly improved.« less

Serological Investigations of Flavivirus Prevalence in Khammouane Province, Lao People's Democratic Republic, 2007–2008

PubMed Central

Hiscox, Alexandra; Winter, Christian H.; Vongphrachanh, Phengta; Sisouk, Thongchanh; Somoulay, Virasack; Phompida, Samlane; Kaul, Surinder; Sananikhom, Pany; Yen, Nguyen Thi; Paul, Richard E.; Brey, Paul; Bryant, Juliet E.

2010-01-01

A large-scale cross-sectional seroprevalence study of dengue (DEN) and Japanese encephalitis (JE) was conducted in Khammouane province, Lao PDR, as part of the initial baseline health impact assessment of the Nam Theun 2 hydroelectric dam construction project. Health surveys were performed between May 2007 and February 2008 with serum samples collected from healthy individuals involved in the resettlement program of 16 villages (total surveyed population 4,369). Hemagglutination inhibition assay using flavivirus antigens (DENV1, DENV3, and JEV) performed on 1,708 plasma specimens revealed 30.4% (519) cross-reactive positives, and 10% (172) and 1.3% (22) positives to JEV or DENV, respectively. Entomological surveys conducted during the rainy season of 2008 indicated the presence of competent flavivirus vectors (Culex vishnui group and Aedes albopictus), although Aedes aegypti was not found. Continued surveillance and investigation is warranted to assess the clinical disease burden of flaviviruses in this area that is undergoing rapid ecological and demographic change. PMID:21036856

[Structural Damage to the Hamstring Graft due to Interaction with Fixation Material and its Effect on Biomechanical Properties of ACL Reconstruction].

PubMed

Kautzner, J; Držík, M; Handl, M; Povýšil, C; Kos, P; Trč, T; Havlas, V

2017-01-01

PURPOSE OF THE STUDY Hamstring grafts are commonly used for ACL reconstruction. The purpose of our study is to determine the effects of the suspension fixation compared to graft cross-pinning transfixation, and the effect(s) of structural damage during the preparation of the graft on biomechanical properties of the graft. MATERIAL AND METHODS The design of the study is a cadaveric biomechanical laboratory study. 38 fresh-frozen human hamstring specimens from 19 cadaveric donors were used. The grafts were tested for their loading properties. One half of each specimen was suspended over a 3.3mm pin, the other half was cross-pinned by a 3.3mm pin to simulate the graft cross-pinning technique. Single impact testing was performed and the failure force, elongation and acceleration/deceleration of each graft was recorded and the loading force vs. elongation of the graft specimens was calculated. Results for suspended and cross-pinned grafts were analysed using ANOVA method, comparing the grafts from each donor. RESULTS The ultimate strength of a double-strand gracilis graft was 1287 ± 134 N when suspended over a pin, the strength of a cross-pinned graft was 833 ± 111 N. For double-strand semitendinosus grafts the strengths were 1883 ± 198 and 997 ± 234 N, respectively. Thus, the failure load for the cross-pinning method is only 64.7% or 52.9% for the suspension method. DISCUSSION Structural damage to the graft significantly reduces the graft strength. Also, extensive suturing during preparation of the graft reduces its strength. CONCLUSIONS Fixation methods that do not interfere with the graft's structure should be used to reduce the risk of graft failure. Key words: ACL reconstruction, hamstring graft, biomechanical testing.

Investigation of interfacial fracture behavior on injection molded parts

NASA Astrophysics Data System (ADS)

Fischer, Matthieu; Ausias, Gilles; Kuehnert, Ines

2016-03-01

In this study the interfacial morphology of different polymers joined by various assembly injection molding (AIM) technologies were discussed. Melt streams were injected successively using tools with core-back or rotation techniques. To compare bulk specimen strength and weld line strength, the fracture behavior of different specimen scales and thin sections were investigated. An in-situ SEM tensile test and a new thin section testing device which is used in polarized (transmitted) light microscopy were used to observe specimen failure. The effects of processing on spherulitic structures were linked to bonding strength and mechanical properties.

A Tissue-Specific Approach to the Analysis of Metabolic Changes in Caenorhabditis elegans

PubMed Central

Pujol, Claire; Ipsen, Sabine; Brodesser, Susanne; Mourier, Arnaud; Tolnay, Markus; Frank, Stephan; Trifunović, Aleksandra

2011-01-01

The majority of metabolic principles are evolutionarily conserved from nematodes to humans. Caenorhabditis elegans has widely accelerated the discovery of new genes important to maintain organismic metabolic homeostasis. Various methods exist to assess the metabolic state in worms, yet they often require large animal numbers and tend to be performed as bulk analyses of whole worm homogenates, thereby largely precluding a detailed studies of metabolic changes in specific worm tissues. Here, we have adapted well-established histochemical methods for the use on C. elegans fresh frozen sections and demonstrate their validity for analyses of morphological and metabolic changes on tissue level in wild type and various mutant strains. We show how the worm presents on hematoxylin and eosin (H&E) stained sections and demonstrate their usefulness in monitoring and the identification of morphological abnormalities. In addition, we demonstrate how Oil-Red-O staining on frozen worm cross-sections permits quantification of lipid storage, avoiding the artifact-prone fixation and permeabilization procedures of traditional whole-mount protocols. We also adjusted standard enzymatic stains for respiratory chain subunits (NADH, SDH, and COX) to monitor metabolic states of various C. elegans tissues. In summary, the protocols presented here provide technical guidance to obtain robust, reproducible and quantifiable tissue-specific data on worm morphology as well as carbohydrate, lipid and mitochondrial energy metabolism that cannot be obtained through traditional biochemical bulk analyses of worm homogenates. Furthermore, analysis of worm cross-sections overcomes the common problem with quantification in three-dimensional whole-mount specimens. PMID:22162770

DNA Sequences from Formalin-Fixed Nematodes: Integrating Molecular and Morphological Approaches to Taxonomy

PubMed Central

Thomas, W. Kelley; Vida, J. T.; Frisse, Linda M.; Mundo, Manuel; Baldwin, James G.

1997-01-01

To effectively integrate DNA sequence analysis and classical nematode taxonomy, we must be able to obtain DNA sequences from formalin-fixed specimens. Microdissected sections of nematodes were removed from specimens fixed in formalin, using standard protocols and without destroying morphological features. The fixed sections provided sufficient template for multiple polymerase chain reaction-based DNA sequence analyses. PMID:19274156

Early Experience after Developing a Pathology Laboratory in Malawi, with Emphasis on Cancer Diagnoses

PubMed Central

Horner, Marie-Josephe; Shores, Carol G.; Alide, Noor; Kamiza, Steve; Kampani, Coxcilly; Chimzimu, Fred; Fedoriw, Yuri; Dittmer, Dirk P.; Hosseinipour, Mina C.; Hoffman, Irving F.

2013-01-01

Background Despite increasing cancer burden in Malawi, pathology services are limited. We describe operations during the first 20 months of a new pathology laboratory in Lilongwe, with emphasis on cancer diagnoses. Methods and Findings We performed a cross-sectional study of specimens from the Kamuzu Central Hospital pathology laboratory between July 1, 2011 and February 28, 2013. Patient and specimen characteristics, and final diagnoses are summarized. Diagnoses were categorized as malignant, premalignant, infectious, other pathology, normal or benign, or nondiagnostic. Patient characteristics associated with premalignancy and malignancy were assessed using logistic regression. Of 2772 specimens, 2758 (99%) with a recorded final diagnosis were included, drawn from 2639 unique patients. Mean age was 38 years and 63% were female. Of those with documented HIV status, 51% had unknown status, and 36% with known status were infected. Histologic specimens comprised 91% of cases, and cytologic specimens 9%. Malignant diagnoses were most common overall (n = 861, 31%). Among cancers, cervical cancer was most common (n = 117, 14%), followed by lymphoma (n = 91, 11%), esophageal cancer (n = 86, 10%), sarcoma excluding Kaposi sarcoma (n = 75, 9%), and breast cancer (n = 61, 7%). HIV status was known for 95 (11%) of malignancies, with HIV prevalence ranging from 9% for breast cancer to 81% for cervical cancer. Increasing age was consistently associated with malignancy [bivariable odds ratio 1.24 per decade increase (95% CI 1.19–1.29) among 2685 patients with known age; multivariable odds ratio 1.33 per decade increase (95% CI 1.14–1.56) among 317 patients with known age, gender, and HIV status], while HIV infection and gender were not. Conclusions Despite selection and referral bias inherent in these data, a new pathology laboratory in Lilongwe has created a robust platform for cancer care and research. Strategies to effectively capture clinical information for pathologically confirmed cancers can allow these data to complement population-based registration. PMID:23950924

Identification of non-tuberculous mycobacteria isolated from clinical specimens at a tertiary care hospital: a cross-sectional study

PubMed Central

2013-01-01

Background Non-tuberculous mycobacteria (NTM) are opportunistic pathogens in immuno-compromised patients. They are also increasingly recognized as pathogens in immuno-competent individuals. Globally, an increase in NTM isolation is being reported with a varied geographic prevalence of different species around the world. There is lack of data on species distribution of these organisms from Pakistan. Treatment options differ according to the species isolated and its susceptibility profile. Knowledge of local species variation would help targeted therapy. This study was performed to determine frequencies of different NTM species isolated from various clinical specimens submitted at a tertiary care hospital laboratory. Methods NTM isolated from 25955 clinical specimens over a period of two years (2010 to 2011) were included. All NTM were identified using conventional tests. Drug susceptibility testing (DST) was performed by broth microdilution and interpreted according to Clinical and Laboratory Standards Institute’s document M24-A2. Results A total of 104 NTM were included in the study. Of these, 76% (54/71) rapidly growing mycobacteria (RGM) and 57.6% (19/33) slow growing mycobacteria (SGM) could be further identified. Mycobacterium fortuitum (21/54) was the commonest NTM identified among RGM followed by M. mucogenicum (12/54) and M. smegmatis (11/54). Among SGM, M. avium complex (MAC) was the most frequent (14/19). Clinical significance could be assessed in a limited number (52/104) of NTM isolates and MAC appeared to be the commonest significant NTM. Three extra-pulmonary cases were found to be healthcare associated infections. DST results for RGM showed susceptibility to amikacin (100%), clarithromycin (100%, except M. fortuitum where it is not reportable), linezolid (90%) and moxifloxacin (75%). Whereas SGM were susceptible to clarithromycin (100%), linezolid (58.8%) and moxifloxacin (64.7%). Conclusion This is the first study reporting NTM species and their clinical significance isolated from clinical specimens from Pakistan. Isolation of NTM from clinical specimens should prompt to evaluate their clinical significance. PMID:24148198

Identification of non-tuberculous mycobacteria isolated from clinical specimens at a tertiary care hospital: a cross-sectional study.

PubMed

Ahmed, Imran; Jabeen, Kauser; Hasan, Rumina

2013-10-22

Non-tuberculous mycobacteria (NTM) are opportunistic pathogens in immuno-compromised patients. They are also increasingly recognized as pathogens in immuno-competent individuals. Globally, an increase in NTM isolation is being reported with a varied geographic prevalence of different species around the world. There is lack of data on species distribution of these organisms from Pakistan. Treatment options differ according to the species isolated and its susceptibility profile. Knowledge of local species variation would help targeted therapy. This study was performed to determine frequencies of different NTM species isolated from various clinical specimens submitted at a tertiary care hospital laboratory. NTM isolated from 25955 clinical specimens over a period of two years (2010 to 2011) were included. All NTM were identified using conventional tests. Drug susceptibility testing (DST) was performed by broth microdilution and interpreted according to Clinical and Laboratory Standards Institute's document M24-A2. A total of 104 NTM were included in the study. Of these, 76% (54/71) rapidly growing mycobacteria (RGM) and 57.6% (19/33) slow growing mycobacteria (SGM) could be further identified. Mycobacterium fortuitum (21/54) was the commonest NTM identified among RGM followed by M. mucogenicum (12/54) and M. smegmatis (11/54). Among SGM, M. avium complex (MAC) was the most frequent (14/19). Clinical significance could be assessed in a limited number (52/104) of NTM isolates and MAC appeared to be the commonest significant NTM. Three extra-pulmonary cases were found to be healthcare associated infections. DST results for RGM showed susceptibility to amikacin (100%), clarithromycin (100%, except M. fortuitum where it is not reportable), linezolid (90%) and moxifloxacin (75%). Whereas SGM were susceptible to clarithromycin (100%), linezolid (58.8%) and moxifloxacin (64.7%). This is the first study reporting NTM species and their clinical significance isolated from clinical specimens from Pakistan. Isolation of NTM from clinical specimens should prompt to evaluate their clinical significance.

A New Endemic Focus of Chagas Disease in the Northern Region of Veraguas Province, Western Half Panama, Central America

PubMed Central

Saldaña, Azael; Pineda, Vanessa; Martinez, Inri; Santamaria, Giovanna; Santamaria, Ana Maria; Miranda, Aracelis; Calzada, Jose E.

2012-01-01

Background Chagas disease was originally reported in Panama in 1931. Currently, the best knowledge of this zoonosis is restricted to studies done in historically endemic regions. However, little is known about the distribution and epidemiology of Chagas disease in other rural areas of the country. Methods and Findings A cross-sectional descriptive study was carried out between May 2005 – July 2008 in four rural communities of the Santa Fe District, Veraguas Province. The study included an entomologic search to collect triatomines, bloodmeal type identification and infection rate with trypanosomes in collected vectors using a dot- blot and PCR analysis, genotyping of circulating Trypanosoma cruzi (mini-exon gene PCR analysis) and the detection of chagasic antibodies among inhabitants. The vector Rhodnius pallescens was more frequently found in La Culaca and El Pantano communities (788 specimens), where it was a sporadic household visitor. These triatomines presented darker coloration and larger sizescompared with typical specimens collected in Central Panama. Triatoma dimidiata was more common in Sabaneta de El Macho (162 specimens). In one small sub-region (El Macho), 60% of the houses were colonized by this vector. Of the examined R. pallescens, 54.7.0% (88/161) had fed on Didelphis marsupialis, and 24.6% (34/138) of T. dimidiata specimens collected inside houses were positive for human blood. R. pallescens presented an infection index with T. cruzi of 17.7% (24/136), with T. rangeli of 12.5% (17/136) and 50.7% (69/136) were mixed infections. In 117 T. dimidiata domestic specimens the infection index with T. cruzi was 21.4%. Lineage I of T. cruzi was confirmed circulating in these vectors. A T. cruzi infection seroprevalence of 2.3% (24/1,056) was found in this population. Conclusions This is the first report of Chagas disease endemicity in Santa Fe District, and it should be considered a neglected public health problem in this area of Panama. PMID:22558095

Why do nickel-titanium archwires fracture intraorally? Fractographic analysis and failure mechanism of in-vivo fractured wires.

PubMed

Zinelis, Spiros; Eliades, Theodore; Pandis, Nikolaos; Eliades, George; Bourauel, Christoph

2007-07-01

The aim of this study was to characterize intraorally fractured nickel-titanium (Ni-Ti) archwires, determine the type of fracture, assess changes in the alloy's hardness and structure, and propose a mechanism of failure. Eleven Ni-Ti SE 200 and 19 copper-Ni-Ti (both, Ormco, Glendora, Calif) intraorally fractured archwires were collected. The location of fracture (anterior or posterior), wire type, cross section, and period of service before fracture were recorded. The retrieved wires and brand-, type-, and size-matched specimens of unused wires were subjected to scanning electron microscopy to assess the fracture type and morphological variation of fracture site of retrieved specimens, and to Vickers hardness (HV200) testing to investigate the hardness of as-received and in-vivo fractured specimens. Fracture site distribution was statistically analyzed with the chi-square test (alpha = 0.05), whereas the results of the hardness testing were analyzed with 2-way ANOVA with state (control vs in-vivo fractured) and composition (Ni-Ti SE vs copper-Ni-Ti) serving as discriminating variables and the Student-Newman-Keuls test at the 95% confidence level. The fracture site distribution showed a preferential location at the midspan between the premolar and the molar, suggesting that masticatory forces and complex loading during engagement of the wire to the bracket slot and potential intraoral aging might account for fracture incidence. All retrieved wires had the distinct features of brittle fracture without plastic deformation or crack propagation, whereas no increase in hardness was observed for the retrieved specimens. Most fractures sites were in the posterior region of the arch, probably because of the high-magnitude masticatory forces. Brittle fracture without plastic deformation was observed in most Ni-Ti wires regardless of archwire composition. There was no increase in the hardness of the intraorally exposed specimens regardless of wire type. This contradicts previous in-vitro studies and rules out hydrogen embrittlement as the cause of fracture.

Quasi-static axial crushes on woven jute/polyester AA6063T52 composite tubes

NASA Astrophysics Data System (ADS)

Othman, A.; Ismail, AE

2018-04-01

Quasi-static axial loading have been studied in this paper to determine the behaviour of jute/polyester wrapped on aluminium alloy 6063T52. The filler material also was include into crush box specimen, which is polyurethane (PU) and polystyrene (PE) rigid foam at ranging 40 and 45 kg/m3 densities. All specimen profile was fabricated using hand layup techniques and the length of each specimen were fixed at 100 mm as well as diameter and width of the tube at 50.8 mm. The two types of tubular cross-section were studied of round and square thin-walled profiles and the angle of fibre at 450 were analysed for four layers. Thin walled of aluminium was 1.9 mm and end frontal of each specimen of composite were chamfered at 450 to prevent catastrophic failure mode. The specific absorbed energy (SEA) and crush force efficiency (CFE) were analyses for each specimen to see the behaviour on jute/polyester wrapped on metallic structure can give influence the energy management for automotive application. Result show that the four layers’ jute/polyester with filler material show significant value in term of specific absorbed energy compared empty and polyurethane profiles higher 26.66% for empty and 15.19% compared to polyurethane profiles. It has been found that the thin walled square profile of the jute/polyester tubes with polystyrene foam-filled is found higher respectively 27.42% to 13.13% than empty and polyurethane (PU) foam tubes. An introduce filler material onto thin walled composite profiles gave major advantage increases the mean axial load of 31.87% from 32.94 kN to 48.35 kN from empty to polystyrene thin walled round jute/polyester profiles and 31.7% from 23.11 KN to 33.84 kN from empty to polystyrene thin walled square jute/polyester profiles. Failure mechanisms of the axially loaded composite tubes were also observed and discussed.

49 CFR 40.49 - What materials are used to collect urine specimens?

Code of Federal Regulations, 2012 CFR

2012-10-01

... 49 Transportation 1 2012-10-01 2012-10-01 false What materials are used to collect urine specimens? 40.49 Section 40.49 Transportation Office of the Secretary of Transportation PROCEDURES FOR... in DOT Urine Collections § 40.49 What materials are used to collect urine specimens? For each DOT...

49 CFR 40.49 - What materials are used to collect urine specimens?

Code of Federal Regulations, 2014 CFR

2014-10-01

... 49 Transportation 1 2014-10-01 2014-10-01 false What materials are used to collect urine specimens? 40.49 Section 40.49 Transportation Office of the Secretary of Transportation PROCEDURES FOR... in DOT Urine Collections § 40.49 What materials are used to collect urine specimens? For each DOT...

49 CFR 40.49 - What materials are used to collect urine specimens?

Code of Federal Regulations, 2013 CFR

2013-10-01

... 49 Transportation 1 2013-10-01 2013-10-01 false What materials are used to collect urine specimens? 40.49 Section 40.49 Transportation Office of the Secretary of Transportation PROCEDURES FOR... in DOT Urine Collections § 40.49 What materials are used to collect urine specimens? For each DOT...

49 CFR 40.49 - What materials are used to collect urine specimens?

Code of Federal Regulations, 2011 CFR

2011-10-01

... 49 Transportation 1 2011-10-01 2011-10-01 false What materials are used to collect urine specimens? 40.49 Section 40.49 Transportation Office of the Secretary of Transportation PROCEDURES FOR... in DOT Urine Collections § 40.49 What materials are used to collect urine specimens? For each DOT...

49 CFR 40.49 - What materials are used to collect urine specimens?

Code of Federal Regulations, 2010 CFR

2010-10-01

... 49 Transportation 1 2010-10-01 2010-10-01 false What materials are used to collect urine specimens? 40.49 Section 40.49 Transportation Office of the Secretary of Transportation PROCEDURES FOR... in DOT Urine Collections § 40.49 What materials are used to collect urine specimens? For each DOT...

42 CFR 414.510 - Laboratory date of service for clinical laboratory and pathology specimens.

Code of Federal Regulations, 2014 CFR

2014-10-01

... and pathology specimens. 414.510 Section 414.510 Public Health CENTERS FOR MEDICARE & MEDICAID... Laboratory date of service for clinical laboratory and pathology specimens. The date of service for either a clinical laboratory test or the technical component of physician pathology service is as follows: (a...

42 CFR 414.510 - Laboratory date of service for clinical laboratory and pathology specimens.

Code of Federal Regulations, 2012 CFR

2012-10-01

... and pathology specimens. 414.510 Section 414.510 Public Health CENTERS FOR MEDICARE & MEDICAID... Laboratory date of service for clinical laboratory and pathology specimens. The date of service for either a clinical laboratory test or the technical component of physician pathology service is as follows: (a...

42 CFR 414.510 - Laboratory date of service for clinical laboratory and pathology specimens.

Code of Federal Regulations, 2013 CFR

2013-10-01

... and pathology specimens. 414.510 Section 414.510 Public Health CENTERS FOR MEDICARE & MEDICAID... Laboratory date of service for clinical laboratory and pathology specimens. The date of service for either a clinical laboratory test or the technical component of physician pathology service is as follows: (a...

Measurement of gene expression in archival paraffin-embedded tissues: development and performance of a 92-gene reverse transcriptase-polymerase chain reaction assay.

PubMed

Cronin, Maureen; Pho, Mylan; Dutta, Debjani; Stephans, James C; Shak, Steven; Kiefer, Michael C; Esteban, Jose M; Baker, Joffre B

2004-01-01

Throughout the last decade many laboratories have shown that mRNA levels in formalin-fixed and paraffin-embedded (FPE) tissue specimens can be quantified by reverse transcriptase-polymerase chain reaction (RT-PCR) techniques despite the extensive RNA fragmentation that occurs in tissues so preserved. We have developed RT-PCR methods that are sensitive, precise, and that have multianalyte capability for potential wide use in clinical research and diagnostic assays. Here it is shown that the extent of fragmentation of extracted FPE tissue RNA significantly increases with archive storage time. Probe and primer sets for RT-PCR assays based on amplicons that are both short and homogeneous in length enable effective reference gene-based data normalization for cross comparison of specimens that differ substantially in age. A 48-gene assay used to compare gene expression profiles from the same breast cancer tissue that had been either frozen or FPE showed very similar profiles after reference gene-based normalization. A 92-gene assay, using RNA extracted from three 10- micro m FPE sections of archival breast cancer specimens (dating from 1985 to 2001) yielded analyzable data for these genes in all 62 tested specimens. The results were substantially concordant when estrogen receptor, progesterone receptor, and HER2 receptor status determined by RT-PCR was compared with immunohistochemistry assays for these receptors. Furthermore, the results highlight the advantages of RT-PCR over immunohistochemistry with respect to quantitation and dynamic range. These findings support the development of RT-PCR analysis of FPE tissue RNA as a platform for multianalyte clinical diagnostic tests.

A novel specimen-specific methodology to optimise the alignment of long bones for experimental testing.

PubMed

Cheong, Vee San; Bull, Anthony M J

2015-12-16

The choice of coordinate system and alignment of bone will affect the quantification of mechanical properties obtained during in-vitro biomechanical testing. Where these are used in predictive models, such as finite element analysis, the fidelic description of these properties is paramount. Currently in bending and torsional tests, bones are aligned on a pre-defined fixed span based on the reference system marked out. However, large inter-specimen differences have been reported. This suggests a need for the development of a specimen-specific alignment system for use in experimental work. Eleven ovine tibiae were used in this study and three-dimensional surface meshes were constructed from micro-Computed Tomography scan images. A novel, semi-automated algorithm was developed and applied to the surface meshes to align the whole bone based on its calculated principal directions. Thereafter, the code isolates the optimised location and length of each bone for experimental testing. This resulted in a lowering of the second moment of area about the chosen bending axis in the central region. More importantly, the optimisation method decreases the irregularity of the shape of the cross-sectional slices as the unbiased estimate of the population coefficient of variation of the second moment of area decreased from a range of (0.210-0.435) to (0.145-0.317) in the longitudinal direction, indicating a minimisation of the product moment, which causes eccentric loading. Thus, this methodology serves as an important pre-step to align the bone for mechanical tests or simulation work, is optimised for each specimen, ensures repeatability, and is general enough to be applied to any long bone. Copyright © 2015 Elsevier Ltd. All rights reserved.

Cross-Linked Amylose Bio-Plastic: A Transgenic-Based Compostable Plastic Alternative

PubMed Central

Sagnelli, Domenico; Kemmer, Gerdi Christine; Holse, Mette; Hebelstrup, Kim H.; Bao, Jinsong; Stelte, Wolfgang; Bjerre, Anne-Belinda; Blennow, Andreas

2017-01-01

Bio-plastics and bio-materials are composed of natural or biomass derived polymers, offering solutions to solve immediate environmental issues. Polysaccharide-based bio-plastics represent important alternatives to conventional plastic because of their intrinsic biodegradable nature. Amylose-only (AO), an engineered barley starch with 99% amylose, was tested to produce cross-linked all-natural bioplastic using normal barley starch as a control. Glycerol was used as plasticizer and citrate cross-linking was used to improve the mechanical properties of cross-linked AO starch extrudates. Extrusion converted the control starch from A-type to Vh- and B-type crystals, showing a complete melting of the starch crystals in the raw starch granules. The cross-linked AO and control starch specimens displayed an additional wide-angle diffraction reflection. Phospholipids complexed with Vh-type single helices constituted an integrated part of the AO starch specimens. Gas permeability tests of selected starch-based prototypes demonstrated properties comparable to that of commercial Mater-Bi© plastic. The cross-linked AO prototypes had composting characteristics not different from the control, indicating that the modified starch behaves the same as normal starch. The data shows the feasibility of producing all-natural bioplastic using designer starch as raw material. PMID:28973963

Cross-Linked Amylose Bio-Plastic: A Transgenic-Based Compostable Plastic Alternative.

PubMed

Sagnelli, Domenico; Hooshmand, Kourosh; Kemmer, Gerdi Christine; Kirkensgaard, Jacob J K; Mortensen, Kell; Giosafatto, Concetta Valeria L; Holse, Mette; Hebelstrup, Kim H; Bao, Jinsong; Stelte, Wolfgang; Bjerre, Anne-Belinda; Blennow, Andreas

2017-09-30

Bio-plastics and bio-materials are composed of natural or biomass derived polymers, offering solutions to solve immediate environmental issues. Polysaccharide-based bio-plastics represent important alternatives to conventional plastic because of their intrinsic biodegradable nature. Amylose-only (AO), an engineered barley starch with 99% amylose, was tested to produce cross-linked all-natural bioplastic using normal barley starch as a control. Glycerol was used as plasticizer and citrate cross-linking was used to improve the mechanical properties of cross-linked AO starch extrudates. Extrusion converted the control starch from A-type to Vh- and B-type crystals, showing a complete melting of the starch crystals in the raw starch granules. The cross-linked AO and control starch specimens displayed an additional wide-angle diffraction reflection. Phospholipids complexed with Vh-type single helices constituted an integrated part of the AO starch specimens. Gas permeability tests of selected starch-based prototypes demonstrated properties comparable to that of commercial Mater-Bi © plastic. The cross-linked AO prototypes had composting characteristics not different from the control, indicating that the modified starch behaves the same as normal starch. The data shows the feasibility of producing all-natural bioplastic using designer starch as raw material.

Corrosion Development of Carbon Steel Grids and Shear Connectors in Cracked Composite Beams Exposed to Wet–Dry Cycles in Chloride Environment

PubMed Central

Xue, Wen; Chen, Ju; Jiang, Ao-yu

2018-01-01

The corrosion development of the reinforcement and shear stud connectors in the cracked steel–concrete composite beams under the salt-fog wet–dry cycles is presented in this investigation. Seven identical composite beams with load-induced concrete cracks were exposed to an aggressive chloride environment. The reinforcement and shear connectors were retrieved after specimens underwent a specified number of wet–dry cycles to obtain the corrosion pattern and the cross-section loss at different exposure times and their evolutions. The crack map, the corrosion pattern and the cross-section loss were measured and presented. Based on the experimental results, the influence of crack characteristics, including crack widths, orientations and positions on the corrosion rate and distribution, were accessed. Moreover, the effects of the connecting weldments on the corrosion initiations and patterns were analyzed. It was shown that the corrosion rate would increase with the number of wet–dry cycles. The characteristics of load-induced cracks could have different influences on the steel grids and shear stud connectors. The corrosion tended to initiate from the connecting weldments, due to the potential difference with the parent steel and the aggressive exposure environment, leading to a preferential weldment attack. PMID:29565836

Absence of convincing evidence of Coxiella burnetii infection in Chile: a cross-sectional serosurvey among healthy adults in four different regions.

PubMed

Weitzel, Thomas; López, Javier; Acosta-Jamett, Gerardo; Edouard, Sophie; Parola, Philippe; Abarca, Katia

2016-10-06

Coxiella burnetii is an important zoonotic pathogen of global distribution. Still, in most parts of South America including Chile, systematic epidemiological data are lacking. The presented study aims to determine the seroprevalence of Coxiella burnetii antibodies in healthy adults of four different regions in Chile. A cross-sectional study was performed, which included healthy adults living in rural and urban areas of four cities located in different regions in northern, central, and southern Chile. In urban sectors, households were chosen by double stratified random sampling, while in rural areas convenience sampling was performed. Serum specimens were taken and screened for the presence of IgG antibodies against C. burnetii phase II antigen using a commercial ELISA kit. Positive and indeterminate results were confirmed by a reference laboratory using indirect immunofluorescence assay (IFA). A total of 1112 individuals were included. Of those, 8 were positive by ELISA, but only one sample was confirmed using IFA. Statistical analysis for population freedom from disease revealed a high probability that C. burnetii was absent in our study population. Our work provides the first epidemiological data on human Q fever in Chile indicating either a very low endemicity or the absence of this pathogen in the studied areas.

Monitoring remineralization of enamel subsurface lesions by optical coherence tomography

NASA Astrophysics Data System (ADS)

Mandurah, Mona M.; Sadr, Alireza; Shimada, Yasushi; Kitasako, Yuichi; Nakashima, Syozi; Bakhsh, Turki A.; Tagami, Junji; Sumi, Yasunori

2013-04-01

Optical coherence tomography (OCT) is a potential clinical tool for enamel lesion monitoring. Swept-source OCT findings were compared with cross-sectional nanohardness findings of enamel. Subsurface bovine enamel lesions in three groups were subjected to (1) deionized water (control), (2) phosphoryl oligosaccharide of calcium (POs-Ca) or (3) POs-Ca with 1 ppm fluoride for 14 days. B-scans images were obtained at 1310-nm center wavelength on sound, demineralized and remineralized areas after 4, 7, and 14 days. The specimens were processed for cross-sectional nanoindentation. Reflectivity from enamel that had increased with demineralization decreased with remineralization. An OCT attenuation coefficient parameter (μt), derived based on the Beer-Lambert law as a function of backscatter signal slope, showed a strong linear regression with integrated nanohardness of all regions (p<0.001, r=-0.97). Sound enamel showed the smallest, while demineralized enamel showed the highest μt. In group three, μt was significantly lower at four days than baseline, but remained constant afterwards. In group two, the changes were rather gradual. There was no significant difference between groups two and three at 14 days in nanohardness or μt POs-Ca with fluoride-enhanced nanohardness of the superficial zone. OCT signal attenuation demonstrated a capability for monitoring changes of enamel lesions during remineralization.

Dark-field imaging in coronary atherosclerosis.

PubMed

Hetterich, Holger; Webber, Nicole; Willner, Marian; Herzen, Julia; Birnbacher, Lorenz; Auweter, Sigrid; Schüller, Ulrich; Bamberg, Fabian; Notohamiprodjo, Susan; Bartsch, Harald; Wolf, Johannes; Marschner, Mathias; Pfeiffer, Franz; Reiser, Maximilian; Saam, Tobias

2017-09-01

Dark-field imaging based on small angle X-ray scattering has been shown to be highly sensitive for microcalcifications, e.g. in breast tissue. We hypothesized (i) that high signal areas in dark-field imaging of atherosclerotic plaque are associated with microcalcifications and (ii) that dark-field imaging is more sensitive for microcalcifications than attenuation-based imaging. Fifteen coronary artery specimens were examined at an experimental set-up consisting of X-ray tube (40kV), grating-interferometer and detector. Tomographic dark-field-, attenuation-, and phase-contrast data were simultaneously acquired. Histopathology served as standard of reference. To explore the potential of dark field imaging in a full-body CT system, simulations were carried out with spherical calcifications of different sizes to simulate small and intermediate microcalcifications. Microcalcifications were present in 10/10 (100%) cross-sections with high dark-field signal and without evidence of calcifications in attenuation- or phase contrast. In positive controls with high signal areas in all three modalities, 10/10 (100%) cross-sections showed macrocalcifications. In negative controls without high signal areas, no calcifications were detected. Simulations showed that the microcalcifications generate substantially higher dark-field than attenuation signal. Dark-field imaging is highly sensitive for microcalcifications in coronary atherosclerotic plaque and might provide complementary information in the assessment of plaque instability. Copyright © 2017 Elsevier B.V. All rights reserved.

Morphologic-echocardiographic correlates of Ebstein's malformation.

PubMed

Rusconi, P G; Zuberbuhler, J R; Anderson, R H; Rigby, M L

1991-07-01

The cross-sectional echocardiographic findings were analysed retrospectively in 26 patients with Ebstein's malformation in the light of studies of autopsied specimens from different patients showing this lesion. The salient anatomical feature in diagnosis is the finding of the hinge point of the septal and mural leaflets of the valve within the inlet component of the right ventricle rather than at the atrioventricular junction. The other important feature is the nature of the distal attachment of the leaflets, particularly the anterosuperior one, which can either be in focal or linear fashion. The hinge point of the septal leaflet was noted echocardiographically to be displaced in 19 patients but, significantly, the leaflet was absent in the other seven. Also significant was that the hinge point of the mural leaflet at the crux had been visualized in only 15 of the patients. The anterosuperior leaflet had a distal linear attachment in 20 of the patients, with the anteroseptal commissure becoming a keyhole in six of these through which blood passed to the functional right ventricle. The valve remained a competent structure, even though closing at the junction of atrialized and functional components of the right ventricle rather than at the atrioventricular junction. Cross-sectional echocardiography is the technique of choice with which to display the salient morphological features of Ebstein's malformation.

Compression of Composite Materials: A Review,

DTIC Science & Technology

1987-11-01

epoxy tension face, . and a plexiglass core under the specimen gage-section. A Kevlar /glass phenolic hybrid composite system was evaluated in the...epoxy [0116 specimens, S2/SP-250 7 glass/epoxy [0/±45/9012s specimens, Kevlar 285 weave/Cycom 4143 Aramid/epoxy specimens, unidirectional FP alumina...bundles tested erc- E-glass, T300 graphite, T700 graphite, P75 graphite, Kevlar 49, and FP alumina. " -1. They observed that bundle failure

Measurement of the full-field polymerization shrinkage and depth of cure of dental composites using digital image correlation.

PubMed

Li, Jianying; Fok, Alex S L; Satterthwaite, Julian; Watts, David C

2009-05-01

The aim of this study was to measure the full-field polymerization shrinkage of dental composites using optical image correlation method. Bar specimens of cross-section 4mm x 2mm and length 10mm approximately were light cured with two irradiances, 450 mW/cm(2) and 180 mW/cm(2), respectively. The curing light was generated with Optilux 501 (Kerr) and the two different irradiances were achieved by adjusting the distance between the light tip and the specimen. A single-camera 2D measuring system was used to record the deformation of the composite specimen for 30 min at a frequency of 0.1 Hz. The specimen surface under observation was sprayed with paint to produce sufficient contrast to allow tracking of individual points on the surface. The curing light was applied to one end of the specimen for 40s during which the painted surface was fully covered. After curing, the cover was removed immediately so that deformation of the painted surface could be recorded by the camera. The images were then analyzed with specialist software and the volumetric shrinkage determined along the beam length. A typical shrinkage strain field obtained on a specimen surface was highly non-uniform, even at positions of constant distance from the irradiation surface, indicating possible heterogeneity in material composition and shrinkage behavior in the composite. The maximum volumetric shrinkage strain of approximately 1.5% occurred at a subsurface distance of about 1mm, instead of at the irradiation surface. After reaching its peak value, the shrinkage strain then gradually decreased with increasing distance along the beam length, before leveling off to a value of approximately 0.2% at a distance of 4-5mm. The maximum volumetric shrinkage obtained agreed well with the value of 1.6% reported by the manufacturer for the composite examined in this work. Using irradiance of 180 mW/cm(2) resulted in only slightly less polymerization shrinkage than using irradiance of 450 mW/cm(2). Compared to the other measurement methods, the image correlation method is capable of producing full-field information about the polymerization shrinkage behavior of dental composites.

Principle, system, and applications of tip-enhanced Raman spectroscopy

NASA Astrophysics Data System (ADS)

Zhang, MingQian; Wang, Rui; Wu, XiaoBin; Wang, Jia

2012-08-01

Raman spectroscopy is a powerful technique in chemical information characterization. However, this spectral method is subject to two obstacles in nano-material detection. One is diffraction limited spatial resolution, and the other is its inherent small Raman cross section and weak signaling. To resolve these problems, a new approach has been developed, denoted as tip-enhanced Raman spectroscopy (TERS). TERS is capable of high-resolution and high-sensitivity detection and demonstrated to be a promising spectroscopic and micro-topographic method to characterize nano-materials and nanostructures. In this paper, the principle and experimental system of TERS are discussed. The latest application of TERS in molecule detection, biological specimen identification, nanao-material characterization, and semi-conductor material determination with some specific experimental examples are presented.

Evaluation of multilayer printed wiring boards by metallographic techniques: An illustrated guide to the preparation and inspection of plated-through hole test coupons based on the requirements of Mil-P-55110D

NASA Technical Reports Server (NTRS)

Jellison, J.

1986-01-01

This work is an illustrated handbook containing the rationale and procedure for the evaluation of multilayer printed wiring board construction integrity with respect to plated-through holes in accordance with the requirements of MIL-P-55110D, Printed Wiring Boards. It is intended as a practical aid for those concerned with determining the construction integrity of multilayer boards for high reliability applications. Photomicrographs of cross sectioned holes illustrate defect types, acceptable and unacceptable conditions, and methods of measurement. A procedure for specimen preparation is given, and appropriate paragraphs of the military specification are included and explained.

Acquisition of thin coronal sectional dataset of cadaveric liver.

PubMed

Lou, Li; Liu, Shu Wei; Zhao, Zhen Mei; Tang, Yu Chun; Lin, Xiang Tao

2014-04-01

To obtain the thin coronal sectional anatomic dataset of the liver by using digital freezing milling technique. The upper abdomen of one Chinese adult cadaver was selected as the specimen. After CT and MRI examinations verification of absent liver lesions, the specimen was embedded with gelatin in stand erect position and frozen under profound hypothermia, and the specimen was then serially sectioned from anterior to posterior layer by layer with digital milling machine in the freezing chamber. The sequential images were captured by means of a digital camera and the dataset was imported to imaging workstation. The thin serial section of the liver added up to 699 layers with each layer being 0.2 mm in thickness. The shape, location, structure, intrahepatic vessels and adjacent structures of the liver was displayed clearly on each layer of the coronal sectional slice. CT and MR images through the body were obtained at 1.0 and 3.0 mm intervals, respectively. The methodology reported here is an adaptation of the milling methods previously described, which is a new data acquisition method for sectional anatomy. The thin coronal sectional anatomic dataset of the liver obtained by this technique is of high precision and good quality.

EXAMINATION OF Zr AND Ti RECOMBINER LOOP SPECIMENS

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

Rittenhouse, P.L.

1958-12-19

Cold-worked specimens of iodide zirconium, Zircaloy-2, iodide titanium, and A-55 titanium were tested in a high-pressure recombiner loop in an attempt to duplicate anomalous results obtained in a prior recombiner loop. Hydrogen analyses and metallographic examinations were made on all specimens. The titanium materials and Zircaloy-2 picked up major amounts of hydrogen in the cell section. None of the materials tested showed appreciable hydrogen absorption in the recombiner section. Complete recrystallization occurred in all cell specimens while only Zircaloy-2, of the recombiner specimens, showed any degree of recrystallization. No explanation for this behavior can be given. A survnnary of themore » data obtained in previous recombiner loops is compared with the results of this loop. Conclusions were based on the results of three recombiner loops. Primarlly because of the hydrogen absorption data obtained in all three recombiner loops it is recommended that the zirconium and titunium materials tested not be used in environments similar to those encountered in high pressure recombiner loops. (auth)« less

An Outbreak of Lymphocutaneous Sporotrichosis among Mine-Workers in South Africa.

PubMed

Govender, Nelesh P; Maphanga, Tsidiso G; Zulu, Thokozile G; Patel, Jaymati; Walaza, Sibongile; Jacobs, Charlene; Ebonwu, Joy I; Ntuli, Sindile; Naicker, Serisha D; Thomas, Juno

2015-09-01

The largest outbreak of sporotrichosis occurred between 1938 and 1947 in the gold mines of Witwatersrand in South Africa. Here, we describe an outbreak of lymphocutaneous sporotrichosis that was investigated in a South African gold mine in 2011. Employees working at a reopened section of the mine were recruited for a descriptive cross-sectional study. Informed consent was sought for interview, clinical examination and medical record review. Specimens were collected from participants with active or partially-healed lymphocutaneous lesions. Environmental samples were collected from underground mine levels. Sporothrix isolates were identified by sequencing of the internal transcribed spacer region of the ribosomal gene and the nuclear calmodulin gene. Of 87 male miners, 81 (93%) were interviewed and examined, of whom 29 (36%) had skin lesions; specimens were collected from 17 (59%). Sporotrichosis was laboratory-confirmed among 10 patients and seven had clinically-compatible lesions. Of 42 miners with known HIV status, 11 (26%) were HIV-infected. No cases of disseminated disease were detected. Participants with ≤ 3 years' mining experience had a four times greater odds of developing sporotrichosis than those who had been employed for >3 years (adjusted OR 4.0, 95% CI 1.2-13.1). Isolates from 8 patients were identified as Sporothrix schenckii sensu stricto by calmodulin gene sequencing while environmental isolates were identified as Sporothrix mexicana. S. schenckii sensu stricto was identified as the causative pathogen. Although genetically distinct species were isolated from clinical and environmental sources, it is likely that the source was contaminated soil and untreated wood underground. No cases occurred following recommendations to close sections of the mine, treat timber and encourage consistent use of personal protective equipment. Sporotrichosis is a potentially re-emerging disease where traditional, rather than heavily mechanised, mining techniques are used. Surveillance should be instituted at sentinel locations.

49 CFR 40.51 - What materials are used to send urine specimens to the laboratory?

Code of Federal Regulations, 2013 CFR

2013-10-01

... 49 Transportation 1 2013-10-01 2013-10-01 false What materials are used to send urine specimens to the laboratory? 40.51 Section 40.51 Transportation Office of the Secretary of Transportation... and Supplies Used in DOT Urine Collections § 40.51 What materials are used to send urine specimens to...

49 CFR 40.51 - What materials are used to send urine specimens to the laboratory?

Code of Federal Regulations, 2010 CFR

2010-10-01

... 49 Transportation 1 2010-10-01 2010-10-01 false What materials are used to send urine specimens to the laboratory? 40.51 Section 40.51 Transportation Office of the Secretary of Transportation... and Supplies Used in DOT Urine Collections § 40.51 What materials are used to send urine specimens to...

49 CFR 40.51 - What materials are used to send urine specimens to the laboratory?

Code of Federal Regulations, 2014 CFR

2014-10-01

... 49 Transportation 1 2014-10-01 2014-10-01 false What materials are used to send urine specimens to the laboratory? 40.51 Section 40.51 Transportation Office of the Secretary of Transportation... and Supplies Used in DOT Urine Collections § 40.51 What materials are used to send urine specimens to...

49 CFR 40.51 - What materials are used to send urine specimens to the laboratory?

Code of Federal Regulations, 2011 CFR

2011-10-01

... 49 Transportation 1 2011-10-01 2011-10-01 false What materials are used to send urine specimens to the laboratory? 40.51 Section 40.51 Transportation Office of the Secretary of Transportation... and Supplies Used in DOT Urine Collections § 40.51 What materials are used to send urine specimens to...

49 CFR 40.51 - What materials are used to send urine specimens to the laboratory?

Code of Federal Regulations, 2012 CFR

2012-10-01

... 49 Transportation 1 2012-10-01 2012-10-01 false What materials are used to send urine specimens to the laboratory? 40.51 Section 40.51 Transportation Office of the Secretary of Transportation... and Supplies Used in DOT Urine Collections § 40.51 What materials are used to send urine specimens to...

46 CFR 54.05-5 - Toughness test specimens.

Code of Federal Regulations, 2012 CFR

2012-10-01

... 46 Shipping 2 2012-10-01 2012-10-01 false Toughness test specimens. 54.05-5 Section 54.05-5 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) MARINE ENGINEERING PRESSURE VESSELS Toughness Tests § 54.05-5 Toughness test specimens. (a) Charpy V-notch impact tests. Where required, Charpy V-notch tests shall be conducted in accordanc...

49 CFR 40.175 - What steps does the first laboratory take with a split specimen?

Code of Federal Regulations, 2010 CFR

2010-10-01

... 49 Transportation 1 2010-10-01 2010-10-01 false What steps does the first laboratory take with a split specimen? 40.175 Section 40.175 Transportation Office of the Secretary of Transportation... steps does the first laboratory take with a split specimen? (a) As the laboratory at which the primary...

49 CFR 40.183 - What information do laboratories report to MROs regarding split specimen results?

Code of Federal Regulations, 2011 CFR

2011-10-01

... 49 Transportation 1 2011-10-01 2011-10-01 false What information do laboratories report to MROs regarding split specimen results? 40.183 Section 40.183 Transportation Office of the Secretary of Transportation PROCEDURES FOR TRANSPORTATION WORKPLACE DRUG AND ALCOHOL TESTING PROGRAMS Split Specimen Tests § 40.183 What information do laboratories...

Analysis of anticaries potential of pit and fissures sealants containing amorphous calcium phosphate using synchrotron microtomography.

PubMed

Delben, A C B; Cannon, M; Vieira, A E M; Basso, M D; Danelon, M; Santo, M R E; Stock, S R; Xiao, X; De Carlo, F

2015-01-01

The aim of this study was to analyze the anticaries potential of pit and fissure sealants containing amorphous calcium phosphate (ACP) by synchrotron microtomography. Bovine enamel blocks (4×4 mm; n=50) were selected through surface hardness (Knoop) analysis. Slabs were obtained through cross-sections taken 1 mm from the border of the enamel. Five indentations, spaced 100 μm apart, were made 300 μm from the border. Ten specimens were prepared for each tested material (Ultraseal XT plus TM, Aegis, Embrace, Vitremer and Experimental Sealant). The materials were randomly attached to the sectioned surfaces of the enamel blocks and fixed with sticky wax. The specimens were submitted to pH cycling. After that, the surface hardness (SH1) was determined, and the blocks were submitted to synchrotron microcomputed tomography analysis to calculate the mineral concentration (ΔgHAp cm(-3)) at different areas of the enamel. The comparison between the SH1 and ΔgHAp cm(-3) showed a correlation for all groups (r=0.840; p<0.001). The fluoride groups presented positive values of ΔgHAp cm(-3), indicating a mineral gain that was observed mainly in the outer part of the enamel. The ACP showed mineral loss in the outer enamel compared with fluoride groups, although it inhibited the demineralization in the deeper areas of enamel. The combination of two remineralizing agents (fluoride and ACP) was highly effective in preventing demineralization.

Anatomy of the interosseous region of the sacroiliac joint.

PubMed

Rosatelli, Alessandro L; Agur, Anne M; Chhaya, Sam

2006-04-01

Anatomical study of the interosseous region of the sacroiliac joint (SIJ) complex. To document and quantify the surface topography of the interosseous region of the SIJ. A review of the literature reveals that little consideration has been given to the interosseous region of the SIJ anatomically, biomechanically, and clinically. The interosseous region of 11 cadaveric specimens (9 formalin embalmed and 2 fresh frozen) were studied. Ten specimens were 55 years of age or older and 1 was 20 years old. To view the interosseous surfaces of the sacrum and ilium the specimens were either axially sectioned (1-cm slices) or disarticulated. One fresh-frozen and 6 embalmed specimens were disarticulated and the remainder axially sectioned. The topography (surface ridging and areas of ossification) of the interosseous region was documented in all specimens and in 2 specimens the surfaces were 3-dimensionally reconstructed using modeling and animation software (MAYA; Autodesk, Inc, San Rafael, CA). Surface characteristics of the SIJ complex observed in specimens 55 years of age or older included moderate to extensive ridging of the interosseous region of the sacrum and ilium in 100% of specimens and ossification of the central interosseous region of the sacroiliac (SI) ligament in 60% of specimens. Central region ossification of the interosseous SI ligament and the presence of ridges and depressions over the opposing interosseous surfaces of the sacrum and ilium are features common to specimens that are in or beyond their sixth decade. These findings further support the contention that there is little to no movement available at this joint in older individuals.

High-Speed Photographic Study of Wave Propagation and Impact Damage in Fused Silica and AlON Using the Edge-On Impact (EOI) Method

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

Strassburger, E.; Patel, P.; McCauley, J. W.

An Edge-on Impact (EOI) technique, developed at the Ernst-Mach-Institute (EMI), coupled with a Cranz-Schardin high-speed camera, has been successfully utilized to visualize dynamic fracture in many brittle materials. In a typical test, the projectile strikes one edge of a specimen and damage formation and fracture propagation is recorded during the first 20 {mu}s after impact. In the present study, stress waves and damage propagation in fused silica and AlON were examined by means of two modified Edge-on Impact arrangements. In one arrangement, fracture propagation was observed simultaneously in side and top views of the specimens by means of two Cranz-Schardinmore » cameras. In another arrangement, the photographic technique was modified by placing the specimen between crossed polarizers and using the photo-elastic effect to visualize the stress waves. Pairs of impact tests at approximately equivalent velocities were carried out in transmitted plane (shadowgraphs) and crossed polarized light.« less

Effect of monomer composition of polymer matrix on flexural properties of glass fibre-reinforced orthodontic archwire.

PubMed

Ohtonen, J; Vallittu, P K; Lassila, L V J

2013-02-01

To compare force levels obtained from glass fibre-reinforced composite (FRC) archwires. Specifically, FRC wires were compared with polymer matrices having different dimethacrylate monomer compositions. FRC material (E-glass provided by Stick Tech Ltd, Turku, Finland) with continuous unidirectional glass fibres and four different types of dimethacrylate monomer compositions for the resin matrix were tested. Cross-sectionally round FRC archwires fitting into the 0.3 mm slot of a bracket were divided into 16 groups with six specimens in each group. Glass fibres were impregnated by the manufacturer, and they were initially light-cured by hand light-curing unit or additionally post-cured in light-curing oven. The FRC archwire specimens were tested at 37°C according to a three-point bending test in dry and wet conditions using a span length of 10 mm and a crosshead speed of 1.0 mm/minute. The wires were loaded until final failure. The data were statistically analysed using analysis of variance (ANOVA). The dry FRC archwire specimens revealed higher load values than water stored ones, regardless of the polymer matrix. A majority of the FRC archwires showed higher load values after being post-cured. ANOVA revealed that the polymer matrix, curing method, and water storage had a significant effect (P < 0.05) on the flexural behaviour of the FRC archwire. Polymer matrix composition, curing method, and water storage affected the flexural properties and thus, force level and working range which could be obtained from the FRC archwire.

Hydrate morphology: Physical properties of sands with patchy hydrate saturation

USGS Publications Warehouse

Dai, S.; Santamarina, J.C.; Waite, William F.; Kneafsey, T.J.

2012-01-01

The physical properties of gas hydrate-bearing sediments depend on the volume fraction and spatial distribution of the hydrate phase. The host sediment grain size and the state of effective stress determine the hydrate morphology in sediments; this information can be used to significantly constrain estimates of the physical properties of hydrate-bearing sediments, including the coarse-grained sands subjected to high effective stress that are of interest as potential energy resources. Reported data and physical analyses suggest hydrate-bearing sands contain a heterogeneous, patchy hydrate distribution, whereby zones with 100% pore-space hydrate saturation are embedded in hydrate-free sand. Accounting for patchy rather than homogeneous hydrate distribution yields more tightly constrained estimates of physical properties in hydrate-bearing sands and captures observed physical-property dependencies on hydrate saturation. For example, numerical modeling results of sands with patchy saturation agree with experimental observation, showing a transition in stiffness starting near the series bound at low hydrate saturations but moving toward the parallel bound at high hydrate saturations. The hydrate-patch size itself impacts the physical properties of hydrate-bearing sediments; for example, at constant hydrate saturation, we find that conductivity (electrical, hydraulic and thermal) increases as the number of hydrate-saturated patches increases. This increase reflects the larger number of conductive flow paths that exist in specimens with many small hydrate-saturated patches in comparison to specimens in which a few large hydrate saturated patches can block flow over a significant cross-section of the specimen.

Socio-demographic and structural barriers to being tested for chlamydia in general practice.

PubMed

Lau, Andrew; Spark, Simone; Tomnay, Jane; Smith, Meredith T; Fairley, Christopher K; Guy, Rebecca J; Donovan, Basil; Hocking, Jane S

2016-02-15

To investigate socio-demographic and structural factors associated with not providing a specimen for chlamydia testing following a request by a general practitioner. Cross-sectional analysis of chlamydia testing data for men and women aged 16-29 years attending general practice clinics participating in a cluster randomised controlled trial evaluating the effectiveness of a chlamydia testing intervention. The study period was the 2013 calendar year. The proportion of chlamydia test requests for which the patient did not provide a specimen for testing. During the study period, there were 13 225 chlamydia test requests, for which a chlamydia test was not performed in 2545 instances (19.2%; 95% CI, 16.5-22.3%). Multivariate analysis indicated that the odds for not undertaking a requested test were higher for men (adjusted odds ratio [aOR], 1.4; 95% CI, 1.3-1.6), those aged 16-19 years (aOR, 1.3; 95% CI, 1.1-1.4), those living in areas of greater socio-economic disadvantage (aOR, 1.2; 95% CI, 1.1-1.4 for each additional quintile of Index of Relative Socio-economic Disadvantage), and those attending clinics without on-site pathology collection (aOR, 1.4; 95% CI, 1.0-1.9). One in five young people did not submit a specimen for chlamydia testing despite their GP requesting it. This highlights the need for clinics to establish systems which ensure that men and those aged 16-19 years undertake chlamydia tests requested by a GP.

The study of the oipA and dupA genes in Helicobacter pylori strains and their relationship with different gastroduodenal diseases.

PubMed

Souod, Negar; Sarshar, Meysam; Dabiri, Hossein; Momtaz, Hassan; Kargar, Mohammad; Mohammadzadeh, Alireza; Abdi, Saeed

2015-01-01

The purpose of this investigation was to determine the oipA and dupA genes of Helicobacter pylori isolates from west of Iran; Chaharmahalo Bakhtiyari region and find their relationship with the severity of the gastroduodenal diseases. Helicobacter pylori is an organism responsible for many gastroduodenal diseases. Many studies suggest that genetic diversity in H . pylori virulence factors such as oipA and dupA genes is high among isolates of different geographic regions and may cause more severe diseases. In this cross-sectional study, gastric biopsy specimens were taken from 150 patients suffering from gastroduodenal diseases. The presence of ureC, dupA and oipA genes was tested by polymerase chain reaction (PCR). Overall, 123 (82%) H. pylori strains were isolated from 150 specimens. dupA gene was detected in 41 (33.33%) H.pylori-positive specimens. There was a reverse correlation between this gene and gastric cancer. The oipA gene was found in 88 (71.54%) samples and statistically there was no association between this gene and gastric disorders. As statistical analyses revealed, the presence of the dupA was more common in isolates with the oipA negative. Based on our findings, the presence of dupA gene can be considered as a marker for the onset of severe diseases. However, the oipA gene cannot be regarded for prediction of gastroenterology diseases. Meanwhile, extended molecular epidemiology researches in other populations are recommended.

The Impact Response of Carbon/Epoxy Laminates (Center Director's Discretionary Fund, Project No. 94-13)

NASA Technical Reports Server (NTRS)

Nettles, A. T.; Hodge, A. J.

1997-01-01

Low velocity dropweight impact tests were conducted on carbon/epoxy laminates under various boundary conditions. The composite plates were 8-ply (+45,0,-45,90)s laminates supported in a clamped-clamped/free-free configuration with varying amounts of in-plane load, N(sub x), applied. Specimens were impacted at energies of 3.4, 4.5, and 6 Joules (2.5, 3.3, and 4.4 ft-lb). The amount of damage induced into the specimen was evaluated using instrumented impact techniques, x-ray inspection, and cross-sectional photomicroscopy. Some static identation tests were performed to examine if the impact events utilized in this study were of a quasi-static nature and also to gain insight into the shape of the deflected surface at various impact load combinations. Load-displacement curves from these tests were compared to those of the impact tests, as was damage determined from x-ray inspection. The finite element technique was used to model the impact event and determine the stress field within the laminae. Results showed that for a given impact energy level, more damage was induced into the specimen as the external in-plane load, N(sub x), was increased. The majority of damage observed consisted of back face splitting of the matrix parallel to the fibers in that ply, associated with delaminations emanating from these splits. The analysis showed qualitatively the results of impact conditions on maximum load of impact, maximum transverse deflection, and first failure mode and location.

Sagittal and vertical load-deflection and permanent deformation of transpalatal arches connected with palatal implants: an in-vitro study.

PubMed

Crismani, Adriano G; Celar, Ales G; Burstone, Charles J; Bernhart, Thomas G; Bantleon, Hans-Peter; Mittlboeck, Martina

2007-06-01

The purposes of this laboratory investigation were to (1) measure the sagittal and vertical deflection of loaded transpalatal arches (TPAs) connected to a palatal implant, (2) measure the extent of permanent deformation of the connecting TPA in the sagittal and vertical directions, (3) test various wire dimensions in terms of deflection behavior, and (4) evaluate soldering vs laser welding vs adhesive bonding of TPAs in terms of load deflection behavior. Stainless steel wires of 6 dimensions were tested: 0.8 x 0.8, 0.9, 1, 1.1, 1.2, and 1.2 x 1.2 mm. For each dimension, 10 specimens were soldered to the palatal implant abutment, 10 were laser welded, and 10 were adhesively bonded to the implant abutment (total, 180 specimens). The measuring device applied increments of force of 50 cN, from 0 to 500 cN. Then the specimens were unloaded. The values were statistically described and analyzed with ANOVA and Wilcoxon rank sum tests. Absolute orthodontic anchorage without deformation of TPAs was not observed with the wire dimensions tested. To prevent loss of anchorage greater than 370 mum (sagittal deflection of 1.2 x 1.2 mm adhesively bonded TPA at 500 cN force level), wires thicker than 1.2 x 1.2 mm or cast anchorage elements must be considered for clinical practice. However, larger cross sections might cause more patient discomfort, and laboratory procedures increase costs.

Photogrammetric analysis of concrete specimens and structures for condition assessment

NASA Astrophysics Data System (ADS)

D'Amico, Nicolas; Yu, Tzuyang

2016-04-01

Deterioration of civil infrastructure in America demands routine inspection and maintenance to avoid catastrophic failures from occurring. Among many other non-destructive evaluations (NDE), photogrammetry is an accessible and realistic approach used for non-destructive evaluation (NDE) of a civil infrastructure systems. The objective of this paper is to explore the capabilities of photogrammetry for locating, sizing, and analyzing the remaining capacity of a specimen or system using point cloud data. Geometric interpretations, composed from up to 70 photographs are analyzed as a mesh or point cloud models. In this case study, concrete, which exhibits a large amount of surface texture features, was thoroughly examined. These evaluative techniques discussed were applied to concrete cylinder models as well as portions of civil infrastructure including buildings, retaining walls, and bridge abutments. In this paper, the aim is to demonstrate the basic analytical functionality of photogrammetry, as well as its applicability to in-situ civil infrastructure systems. In concrete specimens defect length and location can be evaluated in a fully defined model (one with the maximum amount of correctly acquired photographs) with less than 2% error. Error was found to be inversely proportional to the number of acceptable photographs acquired, remaining significantly under 10% error for any model with enough data to render. Furthermore, volumetric stress evaluations were applied using a cross sectional evaluation technique to locate the critical area, and determine the severity of damages. Finally, findings and the accuracy of the results are discussed.

The fatigue growth of internal delaminations under compressive loading of cross-ply composite plates

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

Pelegri, A.A.; Kardomateas, G.A.; Malik, B.U.

1997-12-31

This study focuses on the mode dependence of delamination growth under cyclic compressive loads in cross-ply composite plates. The model proposed makes use of an initial postbuckling solution derived from a perturbation procedure. A mode-dependent crack growth criterion is introduced. Expressions describing the fatigue crack growth are derived in terms of the distribution of the mode adjusted energy release rate. The resulting crack growth laws are numerically integrated to produce delamination growth versus number of cycles diagrams. The model does not impose any restrictive assumptions on the relative thickness of the delaminated and the base plates, although transverse shear stressmore » effects are not considered. Experimental results are presented for cross-ply graphite/epoxy specimens, and the results are compared with experimental results for unidirectional specimens. The test data are obtained for different delamination locations and for different values of applied compressive strain.« less

Flat tensile specimen design for advanced composites

NASA Technical Reports Server (NTRS)

Worthem, Dennis W.

1990-01-01

Finite element analyses of flat, reduced gage section tensile specimens with various transition region contours were performed. Within dimensional constraints, such as maximum length, tab region width, gage width, gage length, and minimum tab length, a transition contour radius of 41.9 cm produced the lowest stress values in the specimen transition region. The stresses in the transition region were not sensitive to specimen material properties. The stresses in the tab region were sensitive to specimen composite and/or tab material properties. An evaluation of stresses with different specimen composite and tab material combinations must account for material nonlinearity of both the tab and the specimen composite. Material nonlinearity can either relieve stresses in the composite under the tab or elevate them to cause failure under the tab.

Rapid embedding methods into epoxy and LR White resins for morphological and immunological analysis of cryofixed biological specimens.

PubMed

McDonald, Kent L

2014-02-01

A variety of specimens including bacteria, ciliates, choanoflagellates (Salpingoeca rosetta), zebrafish (Danio rerio) embryos, nematode worms (Caenorhabditis elegans), and leaves of white clover (Trifolium repens) plants were high pressure frozen, freeze-substituted, infiltrated with either Epon, Epon-Araldite, or LR White resins, and polymerized. Total processing time from freezing to blocks ready to section was about 6 h. For epoxy embedding the specimens were freeze-substituted in 1% osmium tetroxide plus 0.1% uranyl acetate in acetone. For embedding in LR White the freeze-substitution medium was 0.2% uranyl acetate in acetone. Rapid infiltration was achieved by centrifugation through increasing concentrations of resin followed by polymerization at 100°C for 1.5-2 h. The preservation of ultrastructure was comparable to standard freeze substitution and resin embedding methods that take days to complete. On-section immunolabeling results for actin and tubulin molecules were positive with very low background labeling. The LR White methods offer a safer, quicker, and less-expensive alternative to Lowicryl embedding of specimens processed for on-section immunolabeling without traditional aldehyde fixatives.

The effect of prophylaxis method on microtensile bond strength of indirect restorations to dentin.

PubMed

Soares, C J; Pereira, J C; Souza, S J B; Menezes, M S; Armstrong, S R

2012-01-01

The aim of this study was to evaluate the effect of different materials used for dentin prophylaxis on the microtensile bond strengths (μTBS) of adhesively cemented indirect composite restorations. Sixty bovine incisors had the buccal surface ground with wet #600-grit silicon carbide abrasive paper to obtain a flat exposed superficial dentin and were submitted to different prophylaxis protocols, as follows: 3% hydrogen peroxide (HydP); 0.12% chlorhexidine (Chlo); sodium bicarbonate jet (SodB); 50-μm aluminum oxide air abrasion (AirA); pumice paste (PumP), and control group-water spray (Cont). After prophylaxis protocols a resin composite block (3.0 mm × 5.0 mm × 5.0 mm) was adhesively cemented using dual resin cement (Rely X ARC). After 24 hours of water storage, specimens were serially sectioned perpendicular to the bonded interface into 1-mm-thick slices. Each specimen was trimmed with a diamond bur to an hourglass shape with a cross-sectional area of approximately 1.0 mm(2) at the bonded area. Specimens were tested (μTBS) at 0.5 mm/min using a universal testing machine. Scanning electron microscopy was used to examine the effects of prophylaxis techniques on dentin. Bond strength data (MPa) were analyzed by one-way analysis of variance and failure mode by Fisher test (α=0.05). μTBS data, means (SD), were (different superscripted letters indicate statistically significant differences): AirA, 25.2 (7.2)(a); PumP, 24.1 (7.8)(a); Chlo, 21.5 (5.6)(a); Cont, 20.6 (8.1)(a); HydP(,) 15.5 (7.6)(b); and SodB(,) 11.5 (4.4)(c). The use of aluminum oxide air abrasion, pumice paste, and chlorhexidine before acid etching did not significantly affect μTBS to dentin; however, the use of hydrogen peroxide and sodium bicarbonate jet significantly reduced μTBS.

Epoxy Resins in Electron Microscopy

PubMed Central

Finck, Henry

1960-01-01

A method of embedding biological specimens in araldite 502 (Ciba) has been developed for materials available in the United States. Araldite-embedded tissues are suitable for electron microscopy, but the cutting qualities of the resin necessitates more than routine attention during microtomy. The rather high viscosity of araldite 502 also seems to be an unnecessary handicap. The less viscous epoxy epon 812 (Shell) produces specimens with improved cutting qualities, and has several features—low shrinkage and absence of specimen damage during cure, minimal compression of sections, relative absence of electron beam-induced section damage, etc.—which recommends it as a routine embedding material. The hardness of the cured resin can be easily adjusted by several methods to suit the materials embedded in it. Several problems and advantages of working with sections of epoxy resins are also discussed. PMID:13822825

Rates of in vivo (arterial) and in vitro biocorrosion for pure magnesium.

PubMed

Bowen, Patrick K; Drelich, Adam; Drelich, Jaroslaw; Goldman, Jeremy

2015-01-01

The development of magnesium-based materials for bioabsorbable stents relies heavily on corrosion testing by immersion in pseudophysiological solutions, where magnesium degrades faster than it does in vivo. The quantitative difference in corrosion kinetics in vitro and in vivo is largely unknown, but, if determined, would help reduce dependence on animal models. In order to create a quantitative in vitro-in vivo correlation based on an accepted measure of corrosion (penetration rate), commercially pure magnesium wires were corroded in vivo in the abdominal aortas of rats for 5-32 days, and in vitro for up to 14 days using Dulbecco's modified eagle medium. Cross-sectioning, scanning electron microscopy, image analysis, a modified penetration rate tailored to degraded wires, and empirical modeling were used to analyze the corroded specimens. In vitro penetration rates were consistently higher than comparable in vivo rates by a factor of 1.2-1.9× (±0.2×). For a sample <20% corroded, an approximate in vitro-in vivo multiplier of 1.3 ± 0.2× was applied, whereas a multiplier of 1.8 ± 0.2× became appropriate when the magnesium specimen was 25-35% degraded. © 2014 Wiley Periodicals, Inc.

Investigation Study on Determination of Fracture Strain and Fractuer Forming Limit Curve Using Different Experimental and Numerical Methods

NASA Astrophysics Data System (ADS)

Farahnak, P.; Urbanek, M.; Džugan, J.

2017-09-01

Forming Limit Curve (FLC) is a well-known tool for the evaluation of failure in sheet metal process. However, its experimental determination and evaluation are rather complex. From theoretical point of view, FLC describes initiation of the instability not fracture. During the last years Digital Image Correlation (DIC) techniques have been developed extensively. Throughout this paper, all the measurements were done using DIC and as it is reported in the literature, different approaches to capture necking and fracture phenomena using Cross Section Method (CSM), Time dependent Method (TDM) and Thinning Method (TM) were investigated. Each aforementioned method has some advantages and disadvantages. Moreover, a cruciform specimen was used in order to cover whole FLC in the range between uniaxial to equi-biaxial tension and as an alternative for Nakajima test. Based on above-mentioned uncertainty about the fracture strain, some advanced numerical failure models can describe necking and fracture phenomena accurately with consideration of anisotropic effects. It is noticeable that in this paper, dog-bone, notch and circular disk specimens are used to calibrate Johnson-Cook (J-C) fracture model. The results are discussed for mild steel DC01.

A snail in the long tail: a new Plekocheilus species collected by the ‘Comisión Científica del Pacífico’ (Mollusca, Gastropoda, Amphibulimidae)

PubMed Central

Breure, Abraham S. H.; Araujo, Rafael

2015-01-01

Abstract Among the historical collection gathered by the ‘Comisión Científica del Pacífico’ during 1862–1865, type material was found of one of the species described on the basis of the material collected shortly afterwards. Inspection of the types revealed that only one specimen may be considered as type material of Bulimus aristaceus Crosse, 1869; this specimen is now designated as the lectotype. The other specimens are described as a new species, Plekocheilus (Plekocheilus) cecepeus. PMID:26312021

Microtensile bond strength of composite resin to human enamel prepared using erbium: Yttrium aluminum garnet laser.

PubMed

Delfino, Carina Sinclér; Souza-Zaroni, Wanessa Christine; Corona, Silmara Aparecida Milori; Palma-Dibb, Regina Guenka

2007-02-01

The Erbium: Yttrium Aluminum Garnet (YAG) laser used for preparation of cavity can alter the substrate and it could influence the bond strength of enamel. The aim of this in vitro study was to evaluate the influence of Er:YAG laser's energy using microtensile bond test. Three groups were obtained (cavity preparation) and each group was divided into two subgroups (adhesive system). After that the adhesive protocol was performed, sections with a cross-sectional area of 0.8 mm2 (+/-0.2 mm2) were obtained. The specimens were mounted in a universal testing machine (0.5 mm/min). Statistical analysis showed a decrease in bond strength for lased groups (p < 0.01) and when the total-etching adhesive system was used the laser 300 mJ subgroup showed higher bond strength compared to the laser 250 mJ (p < 0.01). It was concluded that the cavities prepared using laser appear less receptive to adhesive procedures than conventional bur-cut cavities. Copyright 2006 Wiley Periodicals, Inc.

49 CFR 40.63 - What steps does the collector take in the collection process before the employee provides a urine...

Code of Federal Regulations, 2011 CFR

2011-10-01

... collection process before the employee provides a urine specimen? 40.63 Section 40.63 Transportation Office... PROGRAMS Urine Specimen Collections § 40.63 What steps does the collector take in the collection process before the employee provides a urine specimen? As the collector, you must take the following steps before...

49 CFR 40.63 - What steps does the collector take in the collection process before the employee provides a urine...

Code of Federal Regulations, 2013 CFR

2013-10-01

... collection process before the employee provides a urine specimen? 40.63 Section 40.63 Transportation Office... PROGRAMS Urine Specimen Collections § 40.63 What steps does the collector take in the collection process before the employee provides a urine specimen? As the collector, you must take the following steps before...

49 CFR 40.63 - What steps does the collector take in the collection process before the employee provides a urine...

Code of Federal Regulations, 2014 CFR

2014-10-01

... collection process before the employee provides a urine specimen? 40.63 Section 40.63 Transportation Office... PROGRAMS Urine Specimen Collections § 40.63 What steps does the collector take in the collection process before the employee provides a urine specimen? As the collector, you must take the following steps before...

49 CFR 40.63 - What steps does the collector take in the collection process before the employee provides a urine...

Code of Federal Regulations, 2012 CFR

2012-10-01

... collection process before the employee provides a urine specimen? 40.63 Section 40.63 Transportation Office... PROGRAMS Urine Specimen Collections § 40.63 What steps does the collector take in the collection process before the employee provides a urine specimen? As the collector, you must take the following steps before...

50 CFR 23.47 - What are the requirements for export of an Appendix-I plant artificially propagated for...

Code of Federal Regulations, 2011 CFR

2011-10-01

... permit or re-export certificate based on Appendix-II criteria. The specimen is still listed in Appendix I... propagating operation that qualifies under paragraph (d) of this section, or to persons who have acquired a... qualifying specimen. (3) The export permit, and any subsequent re-export certificate, must show the specimen...

The cutting of ultrathin sections with the thickness less than 20 nm from biological specimens embedded in resin blocks.

PubMed

Nebesářová, Jana; Hozák, Pavel; Frank, Luděk; Štěpan, Petr; Vancová, Marie

2016-06-01

Low voltage electron microscopes working in transmission mode, like LVEM5 (Delong Instruments, Czech Republic) working at accelerating voltage 5 kV or scanning electron microscope working in transmission mode with accelerating voltage below 1 kV, require ultrathin sections with the thickness below 20 nm. Decreasing of the primary electron energy leads to enhancement of image contrast, which is especially useful in the case of biological samples composed of elements with low atomic numbers. As a result treatments with heavy metals, like post-fixation with osmium tetroxide or ultrathin section staining, can by omitted. The disadvantage is reduced penetration ability of incident electrons influencing the usable thickness of the specimen resulting in the need of ultrathin sections of under 20 nm thickness. In this study we want to answer basic questions concerning the cutting of extremely ultrathin sections: Is it possible routinely and reproducibly to cut extremely thin sections of biological specimens embedded in commonly used resins with contemporary ultramicrotome techniques and under what conditions? Microsc. Res. Tech. 79:512-517, 2016. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

Microtensile bond strength of different acrylic teeth to high-impact denture base resins.

PubMed

Colebeck, Amanda C; Monaco, Edward A; Pusateri, Christopher R; Davis, Elaine L

2015-01-01

This study evaluated the effect of denture base acrylic, denture tooth composition, and ridge-lap surface treatment on the microtensile bond strength (μTBS) of three commercially available denture teeth and two injection denture processing systems. Sixteen experimental groups were formed (n = 3), according to denture tooth surface treatment (no treatment or surface treatment recommended by the manufacturer), denture base processing technique and acrylic (SR-Ivocap-Ivocap Plus or Success-Lucitone 199), and tooth type-composition at bonding interface (BlueLine DCL-PMMA, Portrait IPN-PMMA, Phonares II-PMMA, Phonares II-NHC). Rectangular bar specimens with a 1 mm(2) cross sectional area were fabricated and subsequently thermocycled at 10,000 cycles between 5°C and 55°C with a 15-second dwell time. Select specimens underwent μTBS testing in a universal testing machine with a 1 kN load cell at 0.5 mm/min crosshead speed. Data were analyzed statistically by two and three-way ANOVA and Tukey post hoc test (α = 0.05). Mean μTBS ranged between 56.2 ± 5.6 and 60.8 ± 5.0 N/mm(2) for the Ivocap Plus specimens and 13.3 ± 5.12 to 60.1 ± 6.0 N/mm(2) for the Lucitone 199 specimens. Among the Ivocap specimens, BlueLine DCL and Phonares II NHC had significantly higher μTBS than Portrait IPN to Ivocap Plus acrylic. There were no statistically significant differences among Blueline, Phonares II PMMA, and Phonares II NHC, or between Phonares II PMMA and Portrait IPN. Within the Luctione 199 specimens, there was a significantly higher μTBS for BlueLine DCL and Phonares II NHC denture teeth with the manufacturer-recommended surface treatment when compared to control surface. BlueLine, Portrait, and Phonares II PMMA groups achieved significantly higher mean μTBS than the Phonares II NHC group. There were no statistically significant differences among BlueLine, Portrait, and Phonares II PMMA groups. When evaluating the μTBS of PMMA and NHC denture teeth to base resins, a stronger bond was achieved using materials produced by the same manufacturer. Within the Luctione 199 specimens, the Phonares II NHC group demonstrated significantly lower bond strength than other specimens, suggesting that gross ridge-lap reduction of NHC denture teeth is not recommended if a base acrylic by a different manufacturer from the tooth is going to be used. © 2014 American College of Prosthodontists.

Human Papillomavirus Genotyping Using an Automated Film-Based Chip Array

PubMed Central

Erali, Maria; Pattison, David C.; Wittwer, Carl T.; Petti, Cathy A.

2009-01-01

The INFINITI HPV-QUAD assay is a commercially available genotyping platform for human papillomavirus (HPV) that uses multiplex PCR, followed by automated processing for primer extension, hybridization, and detection. The analytical performance of the HPV-QUAD assay was evaluated using liquid cervical cytology specimens, and the results were compared with those results obtained using the digene High-Risk HPV hc2 Test (HC2). The specimen types included Surepath and PreservCyt transport media, as well as residual SurePath and HC2 transport media from the HC2 assay. The overall concordance of positive and negative results following the resolution of indeterminate and intermediate results was 83% among the 197 specimens tested. HC2 positive (+) and HPV-QUAD negative (−) results were noted in 24 specimens that were shown by real-time PCR and sequence analysis to contain no HPV, HPV types that were cross-reactive in the HC2 assay, or low virus levels. Conversely, HC2 (−) and HPV-QUAD (+) results were noted in four specimens and were subsequently attributed to cross-contamination. The most common HPV types to be identified in this study were HPV16, HPV18, HPV52/58, and HPV39/56. We show that the HPV-QUAD assay is a user friendly, automated system for the identification of distinct HPV genotypes. Based on its analytical performance, future studies with this platform are warranted to assess its clinical utility for HPV detection and genotyping. PMID:19644025

Human papillomavirus genotyping using an automated film-based chip array.

PubMed

Erali, Maria; Pattison, David C; Wittwer, Carl T; Petti, Cathy A

2009-09-01

The INFINITI HPV-QUAD assay is a commercially available genotyping platform for human papillomavirus (HPV) that uses multiplex PCR, followed by automated processing for primer extension, hybridization, and detection. The analytical performance of the HPV-QUAD assay was evaluated using liquid cervical cytology specimens, and the results were compared with those results obtained using the digene High-Risk HPV hc2 Test (HC2). The specimen types included Surepath and PreservCyt transport media, as well as residual SurePath and HC2 transport media from the HC2 assay. The overall concordance of positive and negative results following the resolution of indeterminate and intermediate results was 83% among the 197 specimens tested. HC2 positive (+) and HPV-QUAD negative (-) results were noted in 24 specimens that were shown by real-time PCR and sequence analysis to contain no HPV, HPV types that were cross-reactive in the HC2 assay, or low virus levels. Conversely, HC2 (-) and HPV-QUAD (+) results were noted in four specimens and were subsequently attributed to cross-contamination. The most common HPV types to be identified in this study were HPV16, HPV18, HPV52/58, and HPV39/56. We show that the HPV-QUAD assay is a user friendly, automated system for the identification of distinct HPV genotypes. Based on its analytical performance, future studies with this platform are warranted to assess its clinical utility for HPV detection and genotyping.

Effect of 457 nm diode-pumped solid state laser on the polymerization composite resins: microhardness, cross-link density, and polymerization shrinkage.

PubMed

Son, Sung-Ae; Park, Jeong-Kil; Jung, Kyoung-Hwa; Ko, Ching-Chang; Jeong, Chang-Mo; Kwon, Yong Hoon

2015-01-01

The purpose of the present study was to test the usefulness of 457 nm diode-pumped solid state (DPSS) laser as a light source to cure composite resins. Five different composite resins were light cured using three different light-curing units (LCUs): a DPSS 457 nm laser (LAS), a light-emitting diode (LED), and quartz-tungsten-halogen (QTH) units. The light intensity of LAS was 560 mW/cm(2), whereas LED and QTH LCUs was ∼900 mW/cm(2). The degree of polymerization was tested by evaluating microhardness, cross-link density, and polymerization shrinkage. Before water immersion, the microhardness of laser-treated specimens ranged from 40.8 to 84.7 HV and from 31.7 to 79.0 HV on the top and bottom surfaces, respectively, and these values were 3.3-23.2% and 2.9-31.1% lower than the highest microhardness obtained using LED or QTH LCUs. Also, laser-treated specimens had lower top and bottom microhardnesses than the other LCUs treated specimens by 2.4-19.4% and 1.4-27.8%, respectively. After ethanol immersion for 24 h, the microhardness of laser-treated specimens ranged from 20.3 to 63.2 HV on top and bottom surfaces, but from 24.9 to 71.5 HV when specimens were cured using the other LCUs. Polymerization shrinkage was 9.8-14.7 μm for laser-treated specimens, and these were significantly similar or lower (10.2-16.0 μm) than those obtained using the other LCUs. The results may suggest that the 457 nm DPSS laser can be used as a light source for light-curing dental resin composites.

High resolution trace element records from the deep sea hydrocoral Stylaster venustus: Implications for stylasterids as a paleoceanographic archive

NASA Astrophysics Data System (ADS)

Aranha, R. S.; Layne, G. D.; Edinger, E.; Piercey, G.

2009-12-01

Stylasterids are one of the lesser known groups of deep sea corals, but appear to have potential to serve as viable geochemical archives for reconstructing temperature, salinity and nutrient regimes in the deep ocean. This group of hydrocorals are present in most, if not all of the world’s major oceans. Stylasterid species dominantly have aragonitic skeletons, with a small percentage of species having calcitic skeletons (1). A recent study on the biomineralization of a deep sea stylasterid (Errina dabneyi) has revealed that during the organism’s growth, a steady dissolution and reprecipitation of skeletal material occurs in the central canals of the skeleton. This skeletal modification likely alters the stable isotope and/or trace element profiles of these corals, making them potentially less reliable as geochemical archives, depending on the scale of sampling (2). Recent specimens of Stylaster venustus were collected in July, 2008 from the Olympic Coast National Marine sanctuary off the coast of Washington at depths of 200 - 350 m. We used a Cameca IMS 4f Secondary Ion Mass Spectrometer (SIMS) to perform high spatial resolution (<25 µm) spot analyses of Sr/Ca, Mg/Ca and Na/Ca in detailed traverses across the basal cross-sections from three of these specimens. We identified the remineralized material by remnant porous texture and/or a substantially different trace element composition. Spot analyses corresponding to the remineralized material were eliminated from the dataset. In all three specimens we observed a pronounced inverse correlation (r = -0.36) of Mg/Ca and Sr/Ca profiles throughout the length of the transects . A positive correlation (r =0.46) between Na/Ca and Mg/Ca profiles was also noted in two of the specimens analyzed. These correlations strongly imply that the coral skeleton is recording either cyclical or episodic variations in temperature, with possible overprinting from other environmental variation. The exact relationship between the visible banding in the skeletal cross-section and any cyclicity of trace element profiles is currently ambiguous. However, our analyses demonstrate that microanalytical techniques are a viable means of extracting trace element records from these corals. Further statistical analysis of the trace element transects, in combination with a variety of imaging analyses of the same samples, should help us elucidate what portion of the geochemical signal is temperature dependent and what magnitude of temperature change is actually being recorded. Correlating these trace element profiles with instrumental temperature records will help confirm that useful geochemical archives are preserved by stylasterid skeletons. References: (1) Cairns SD and Macintyre IG. 1992. Phylogenetic implications of calcium carbonate mineralogy in the Stylasteridae (Cnidaria:Hydrozoa).Palaios 7: 96-107. (2) Wisshak M, López Correa M, Zibrowius H, Jakobsen J & Freiwald. (in press). Skeletal reorganisation affects geochemical signals, exemplified in the stylasterid hydrocoral Errina dabneyi (Azores Archipelago). Marine Ecology Progress Series.

Life prediction and constitutive models for engine hot section anisotropic materials

NASA Technical Reports Server (NTRS)

Swanson, G. A.

1984-01-01

The development of directionally solidified and single crystal alloys is perhaps the most important recent advancement in hot section materials technology. The objective is to develop knowledge that enables the designer to improve anisotropic gas turbine parts to their full potential. Two single crystal alloys selected were PWA 1480 and Alloy 185. The coatings selected were an overlay coating, PWA 286, and an aluminide diffusion coating, PWA 273. The constitutive specimens were solid and cylindrical; the fatigue specimens were hollow and cylindrical. Two thicknesses of substrate are utilized. Specimens of both thickness (0.4 and 1.5 mm) will be coated and then tested for tensile, creep, and fatigue properties.

Behavior of a centrally notched cross-ply and unidirectional ceramic matrix composite in tension-compression fatigue. Master's thesis

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

Weidenaar, W.A.

1992-12-01

Centrally notched (hole), cross-ply, ((0/90) sub 2) sub s, and unidirectional, (0) sub 8 laminates of Silicon Carbide fiber-reinforced Aluminosilicate glass, SiC/1723, were fatigue tested under tension-compression loading with a load ratio of -1. Damage accumulated continuously for both lay-ups, leading to eventual failure and a reduced fatigue life. Critical damage in the cross-ply consisted of longitudinal cracks in the 90 deg plies growing and combining with transverse cracks to effectively eliminate the 90 deg plies' load carrying capability and allowing the specimen to buckle. Critical damage in the unidirectional lay-up consisted of longitudinal cracks which initiated at the shearmore » stress concentration points on the hole periphery. Reversed cyclic loading caused continued crack growth at maximum stresses below the tension-tension fatigue limit. The cross-ply lay-up appeared insensitive to the hole, while critical damage in the unidirectional lay-up was dependent on the shear stress concentrations at the hole.... Ceramic matrix composite, Tension-compression fatigue, Notched specimen.« less

Resistive sensitivity functions for van der Pauw astroid and rounded crosses and cloverleafs

NASA Astrophysics Data System (ADS)

Koon, Daniel; Hansen, Ole

2014-03-01

We have calculated the sensitivity of van der Pauw resistances to local resistive variations for circular, square and astroid discs of infinitesimal thickness, as well as for the families of rounded crosses and cloverleafs, as a function of specimen parameters, using the direct formulas of our recent paper (Koon et al. 2013 J. Appl. Phys.114 163710) applied to ``reciprocally dual geometries'' (swapped Dirichlet and Neumann boundary conditions) described by Mareš et al.(2012 Meas. Sci. Technol. 23 045004). These results show that (a) the product of any such sensitivity function times differential area, and thus (b) the ratio of any two sensitivities, is invariant under conformal mapping, allowing for the pointwise determination of the conformal mapping function. The family of rounded crosses, which is bounded in parameter space by the square, the astroid and an ``infinitesimally thin'' cross, seems to represent the best geometry for focusing transport measurements on the center of the specimen while minimizing errors due to edge- or contact-effects. Made possible by an SLU Faculty research grant.

Quantification of red myotomal muscle volume and geometry in the shortfin mako shark (Isurus oxyrinchus) and the salmon shark (Lamna ditropis) using T1-weighted magnetic resonance imaging.

PubMed

Perry, Cameron N; Cartamil, Daniel P; Bernal, Diego; Sepulveda, Chugey A; Theilmann, Rebecca J; Graham, Jeffrey B; Frank, Lawrence R

2007-04-01

T1-weighted magnetic resonance imaging (MRI) in conjunction with image and segmentation analysis (i.e., the process of digitally partitioning tissues based on specified MR image characteristics) was evaluated as a noninvasive alternative for differentiating muscle fiber types and quantifying the amounts of slow, red aerobic muscle in the shortfin mako shark (Isurus oxyrinchus) and the salmon shark (Lamna ditropis). MRI-determinations of red muscle quantity and position made for the mid-body sections of three mako sharks (73.5-110 cm fork length, FL) are in close agreement (within the 95% confidence intervals) with data obtained for the same sections by the conventional dissection method involving serial cross-sectioning and volumetric analyses, and with previously reported findings for this species. The overall distribution of salmon shark red muscle as a function of body fork length was also found to be consistent with previously acquired serial dissection data for this species; however, MR imaging revealed an anterior shift in peak red muscle cross-sectional area corresponding to an increase in body mass. Moreover, MRI facilitated visualization of the intact and anatomically correct relationship of tendon linking the red muscle and the caudal peduncle. This study thus demonstrates that MRI is effective in acquiring high-resolution three-dimensional digital data with high contrast between different fish tissue types. Relative to serial dissection, MRI allows more precise quantification of the position, volume, and other details about the types of muscle within the fish myotome, while conserving specimen structural integrity. Copyright (c) 2007 Wiley-Liss, Inc.

49 CFR 40.185 - Through what methods and to whom must a laboratory report split specimen results?

Code of Federal Regulations, 2011 CFR

2011-10-01

... 49 Transportation 1 2011-10-01 2011-10-01 false Through what methods and to whom must a laboratory report split specimen results? 40.185 Section 40.185 Transportation Office of the Secretary of Transportation PROCEDURES FOR TRANSPORTATION WORKPLACE DRUG AND ALCOHOL TESTING PROGRAMS Split Specimen Tests § 40.185 Through what methods and to whom...

Local buckling and crippling of composite stiffener sections

NASA Technical Reports Server (NTRS)

Bonanni, David L.; Johnson, Eric R.; Starnes, James H., Jr.

1988-01-01

Local buckling, postbuckling, and crippling (failure) of channel, zee, and I- and J-section stiffeners made of AS4/3502 graphite-epoxy unidirectional tape are studied by experiment and analysis. Thirty-six stiffener specimens were tested statically to failure in axial compression as intermediate length columns. Web width is 1.25 inches for all specimens, and the flange width-to-thickness ratio ranges from 7 to 28 for the specimens tested. The radius of the stiffener corners is either 0.125 or 0.250 inches. A sixteen-ply orthotropic layup, an eight-ply quasi-isotropic layup, and a sixteen-ply quasi-isotropic layup are examined. Geometrically nonlinear analyses of five specimens were performed with the STAGS finite element code. Analytical results are compared to experimental data. Inplane stresses from STAGS are used to conduct a plane stress failure analysis of these specimens. Also, the development of interlaminar stress equations from equilibrium for classical laminated plate theory is presented. An algorithm to compute high order displacement derivatives required by these equations based on the Discrete Fourier Transform (DFT) is discussed.