Internal Structural Features Research Articles

High-resolution three-dimensional in vivo imaging of mouse oviduct using optical coherence tomography.

The understanding of the reproductive events and the molecular mechanisms regulating fertility and infertility in humans relies heavily on the analysis of the corresponding phenotypes in mouse models. While molecular genetic approaches provide significant insight into the molecular regulation of these processes, the lack of live imaging methods that allow for detailed visualization of the mouse reproductive organs limits our investigations of dynamic events taking place during the ovulation, the fertilization and the pre-implantation stages of embryonic development. Here we introduce an in vivo three-dimensional imaging approach for visualizing the mouse oviduct and reproductive events with micro-scale spatial resolution using optical coherence tomography (OCT). This method relies on the natural tissue optical contrast and does not require the application of any contrast agents. For the first time, we present live high-resolution images of the internal structural features of the oviduct, as well as other reproductive organs and the oocytes surrounded by cumulus cells. These results provide the basis for a wide range of live dynamic studies focused on understanding fertility and infertility.

С. Д. Кржижановский-шекспировед: к вопросу об освоении драматургии Шекспира в 1930-е годы (методы и подходы)

In the late 1920s — the early 1930s, Shakespeare studies in the Soviet Union were dominated by the method of ‘vulgar sociology’. This official methodology influenced every scholar of literature. One of the key figures in literary studies of the time was Vladimir M. Friche. A change in attitudes to Shakespeare, caused by the general interest in the heritage of classical authors in the Soviet theater, did not occur until 1934. The article focuses on the yet little researched interpretation of Shakespeare developed in the 1930s by Sigizmund D. Krzhizhanovsky, and his original position in history and cultural scholarship. In particular, we have for the first time analyzed the transcript of Krzhizhanovsky’s paper devoted to Shakespeare’s chronicles. This document is preserved in Fond No. 52, Vserosskomdram at the Department of Manuscripts, Institute of World Literature, Russian Academy of Sciences. The concept of history which underpins Krzhizhanovsky’s interpretation of Shakespeare’s chronicles can be traced back to the problems of methodology of historical knowledge as advanced by German philosophers of the late 19th and early 20th centuries. Among the original interpreters and followers of this approach in Russia were such historians as A.S. Lappo-Danilevsky, I.M. Grevs and N.P. Antsiferov. According to Krzhizhanovsky, Shakespeare selected his historical material with an accuracy of a historian. By studying various Shakespearean characters, historical and fictional, Krzhizhanovsky reconstructs the internal structural features of Shakespeare’s chronicles as a textual poetics through analysis and correlation of historical facts and their interpretation both by Shakespeare’s contemporaries and in the author's imagination. The latter transforms historical facts according to the dramatic canon and creates a fictional world for Shakespeare’s contemporary audience. Krzhizhanovsky argues that, not knowing their own future, spectators are pleased to view themselves as ‘the future’ for historical characters on stage, and to watch the drama of ‘the past’ proceed into the present.

Development and validation of a measure of elementary teachers' science content knowledge in two multiyear teacher professional development intervention projects

Using data collected from two multiyear teacher professional development projects employing randomized control trials, this study describes the development and validation of a paper-based test of elementary teachers' science content knowledge (SCK). Evidence of construct validity is presented, including evidence on internal structural features using Rasch measurement models. Results from 183 treatment group and 176 control group teachers from Project 1 demonstrated that the SCK test had acceptable person reliability at baseline; at later time points the test was easy for the teachers and person reliability was below acceptable. Results from Project 1 informed changes made to the test for use in Project 2, including an increase in the difficulty level and the development of two equated forms. Results from the 148 treatment and 139 control teachers from Project 2 demonstrated that the test had acceptable reliability across two time points and was a better match to teachers' SCK. © 2015 Wiley Periodicals, Inc. J Res Sci Teach 52: 371–396, 2015

Multi-scale Heat Kernel based Volumetric Morphology Signature.

Here we introduce a novel multi-scale heat kernel based regional shape statistical approach that may improve statistical power on the structural analysis. The mechanism of this analysis is driven by the graph spectrum and the heat kernel theory, to capture the volumetric geometry information in the constructed tetrahedral mesh. In order to capture profound volumetric changes, we first use the volumetric Laplace-Beltrami operator to determine the point pair correspondence between two boundary surfaces by computing the streamline in the tetrahedral mesh. Secondly, we propose a multi-scale volumetric morphology signature to describe the transition probability by random walk between the point pairs, which reflects the inherent geometric characteristics. Thirdly, a point distribution model is applied to reduce the dimensionality of the volumetric morphology signatures and generate the internal structure features. The multi-scale and physics based internal structure features may bring stronger statistical power than other traditional methods for volumetric morphology analysis. To validate our method, we apply support vector machine to classify synthetic data and brain MR images. In our experiments, the proposed work outperformed FreeSurfer thickness features in Alzheimer's disease patient and normal control subject classification analysis.

Macro/micro-pore structure characteristics and the chloride penetration of self-compacting concrete incorporating different types of filler and mineral admixture

The relationship between the internal pore structure features at different scales and the local micro-characteristics of the interfacial transition zone (ITZ) to the non-steady state chloride migration coefficient (Dnssm) is investigated for one normal and three types of sustainable high performance self-compacting concrete mixes. The pore structure classification at different scales and the percolation degrees of the ITZ’s pores were determined using both vacuum-saturated and Mercury Intrusion Porosimetry (MIP) techniques. Further, the local micro-permeation features of the ITZ, such as thickness, porosity and the chemistry of its hydration products is examined using the SEM coupled with the EDX analysis on polished, carbon-coated, flat specimens. Chloride movement was achieved using a modified rapid migration test.It was deduced that the degree of percolation of the pores of the ITZ had a significant role in controlling the chloride penetration process. Further, it is proposed that the ITZ thickness might be, primarily, responsible in determining the chloride ions’ migration velocity especially when coarse and unreactive filler are used. At nano scale, it is also suggested that the critical pore diameter in the cement matrix is more significant than is the average pore diameter in controlling the chloride resistance in SCC.

Fused monochromatic imaging acquired by single source dual energy CT in hepatocellular carcinoma during arterial phase: an initial experience.

To explore whether single and fused monochromatic images can improve liver tumor detection and delineation by single source dual energy CT (ssDECT) in patients with hepatocellular carcinoma (HCC) during arterial phase. Fifty-seven patients with HCC who underwent ssDECT scanning at Beijing Cancer Hospital were enrolled retrospectively. Twenty-one sets of monochromatic images from 40 to 140 keV were reconstructed at 5 keV intervals in arterial phase. The optimal contrast-noise ratio (CNR) monochromatic images of the liver tumor and the lowest-noise monochromatic images were selected for image fusion. We evaluated the image quality of the optimal-CNR monochromatic images, the lowest-noise monochromatic images and the fused monochromatic images, respectively. The evaluation indicators included the spatial resolution of the anatomical structure, the noise level, the contrast and CNR of the tumor. In arterial phase, the anatomical structure of the liver can be displayed most clearly in the 65-keV monochromatic images, with the lowest image noise. The optimal-CNR monochromatic images of HCC tumor were 50-keV monochromatic images in which the internal structural features of the liver tumors were displayed most clearly and meticulously. For tumor detection, the fused monochromatic images and the 50-keV monochromatic images had similar performances, and were more sensitive than 65-keV monochromatic images. We achieved good arterial phase images by fusing the optimal-CNR monochromatic images of the HCC tumor and the lowest-noise monochromatic images. The fused images displayed liver tumors and anatomical structures more clearly, which is potentially helpful for identifying more and smaller HCC tumors.

Release behaviour of single pellets and internal fine 3D structural features co-define the in vitro drug release profile.

Multi-pellet formulations are advantageous for the controlled release of drugs over single-unit dosage forms. To understand the diffusion controlled drug release mechanism, the pellet structure and drug release from a single pellet (not at dose level) were studied using synchrotron radiation X-ray computed microtomography (SR-μCT) and a sensitive LC/MS/MS method. The purpose of this article is to introduce a powerful, non-invasive and quantitative technique for studying individual pellet microstructures and to investigate the relationship between the microstructure and drug release from single pellets. The data from the single pellet dissolution measurements demonstrated that the release profile of capsules containing approximately 1,000 pellets per unit dose was the summation of the release profiles of the individual pellets. The release profiles of single tamsulosin hydrochloride (TSH) pellets formed three groups when a cluster analysis was performed, and the dissolution rate of the individual pellets correlated well with the combined effects of the drug loading, volume and surface area of the pellets (R(2) = 0.9429). In addition, the void microstructures within the pellet were critical during drug release. Therefore, SR-μCT is a powerful tool for quantitatively elucidating the three-dimensional microstructure of the individual pellets; because the microstructure controls drug release, it is an important parameter in the quality control of multi-pellet formulations.

Development of Principle of Suitability for Children Scale

The present study was aimed to develop a scale of Principle of Suitability for Children (PSCS). Research has been carried out on 245 teachers, (126 (52%) of them are working in general education classes and 119 (48%) of them are working in kindergarten classes), from two different branches. The opinions of the teachers with regard to the principle of suitability for children have been evaluated by using PSCS. In order to test the factor structure of PSCS, explanatory factor analyses were conducted. As a result of this factor analysis, it was determined that PSCS consists of 35 items under two independent factors named as Internal Structural Features (17 items) and Formal Structural Features (18 items). Lastly, to examine the reliability of PSCS, the inner- consistency of whole scale and its sub factors, split-half and test re-test reliability scores were calculated and observed to have an adequate level.

Study of polycaprolactone wet electrospinning process

Ministry of Interior of the Czech Republic [VG20102014049]; Project OP VaVpI Centre for Nanomaterials, Advanced Technologies and Innovation [CZ.1.05/2.1.00/01.0005]; GACR [P208/12/0105]

Computational and experimental characterization of skin mechanics: identifying current challenges and future directions

The characterization of skin mechanics has many clinical implications and has been an active area of research for the past few decades. Biomechanical models have evolved from earlier empirical models to state-of-the-art structural models that provide linkage between tissue microstructure and macroscopic stress-strain response. To maximize the accuracy and predictive capabilities of such computational models, there is a need to reliably identify often a large number of unknown model parameters. This is critically dependent on the availability of experimental data that cover an extensive range of different deformation modes, and quantification of internal structural features, such as collagen orientation. To this end, future challenges should include the ongoing development of noninvasive instrumentation and imaging modalities for in vivo skin measurements. We highlight the important concept of tightly integrating computational models, instrumentation, and imaging modalities into a single platform to investigate skin biomechanics.

Nanopores in hematite ( -Fe2O3) nanocrystals observed by electron tomography

We report the first characterization of the internal structural features within rhombohedral nanocrystals of hematite (α-Fe2O3), specifically nanoscale pores (nanopores) within these crystals observed by high-angle annular dark-field scanning transmission electron microscopy tomography. Threedimensional observations of the internal structure of hematite nanocrystals suggest that the nanopores are formed due to a large reduction in solid volume during the transformation of a poorly crystalline precursor [aggregates of ferrihydrite: Fe8.2O8.5(OH)7.4·3H2O], which results in the formation of pores between grain boundaries. This formation mechanism is different from those previously reported, such as hollow cores originating from screw dislocations. We also discuss dissolution experiments of the hematite nanocrystals in ascorbic acid solution, in which we demonstrated that the nanopores are reactive sites for dissolution and enlarged by preferential etching. Our findings are of fundamental importance to understanding how certain crystal morphologies, internal structures, defects, and reactive sites occur in nanocrystals formed from a poorly crystalline precursor.

The Roles of Pit Houses and Gendered Spaces on Viking-Age Farmsteads in Iceland

THE SMALL SEMI-SUBTERRANEAN buildings (jarðhús) with slab-built ovens that have been found on many Viking-Age farmsteads in Iceland (late 9th–11th century) have been subject to wide-ranging interpretations, from short-lived, expedient dwellings to saunas, women’s workrooms, the houses of Slavic settlers and in one case a cult building. This paper tests these hypotheses by making a thorough revaluation of pit-house dates, architectural forms, internal structural features and artefacts, and presents new geoarchaeological evidence from the pit house at Hofstaðir, NE Iceland. This lends strong support to the interpretation that they were women’s workrooms, primarily for the production of woollen textiles. Their abandonment in the later 10th and 11th centuries may be interpreted in the light of changing religious beliefs and social structures, the growing importance of homespun cloth as a valuable export commodity, and the rise in status of the women who made it.

Conformational Dynamics of Titin PEVK Explored with FRET Spectroscopy

The proline-, glutamate-, valine-, and lysine-rich (PEVK) domain of the giant muscle protein titin is thought to be an intrinsically unstructured random-coil segment. Various observations suggest, however, that the domain may not be completely devoid of internal interactions and structural features. To test the validity of random polymer models for PEVK, we determined the mean end-to-end distances of an 11- and a 21-residue synthetic PEVK peptide, calculated from the efficiency of the fluorescence resonance energy transfer (FRET) between an N-terminal intrinsic tryptophan donor and a synthetically added C-terminal IAEDANS acceptor obtained in steady-state and time-resolved experiments. We find that the contour-length scaling of mean end-to-end distance deviates from predictions of a purely statistical polymer chain. Furthermore, the addition of guanidine hydrochloride decreased, whereas the addition of salt increased the FRET efficiency, pointing at the disruption of structure-stabilizing interactions. Increasing temperature between 10 and 50°C increased the normalized FRET efficiency in both peptides but with different trajectories, indicating that their elasticity and conformational stability are different. Simulations suggest that whereas the short PEVK peptide displays an overall random structure, the long PEVK peptide retains residual, loose helical configurations. Transitions in the local structure and dynamics of the PEVK domain may play a role in the modulation of passive muscle mechanics.

Fragility of Brushite Stones in Shock Wave Lithotripsy: Absence of Correlation with Computerized Tomography Visible Structure

Brushite stones were imaged in vitro and then broken with shock wave lithotripsy to assess whether stone fragility correlates with internal stone structure visible on helical computerized tomography. A total of 52 brushite calculi were scanned by micro computerized tomography, weighed, hydrated and placed in a radiological phantom. Stones were scanned using a Philips® Brilliance iCT 256 system and images were evaluated for the visibility of internal structural features. The calculi were then treated with shock wave lithotripsy in vitro. The number of shock waves needed to break each stone to completion was recorded. The number of shock waves needed to break each stone normalized to stone weight did not differ by HU value (p = 0.84) or by computerized tomography visible structures that could be identified consistently by all observers (p = 0.053). Stone fragility correlated highly with stone density and brushite content (each p <0.001). Calculi of almost pure brushite required the most shock waves to break. When all observations of computerized tomography visible structures were used for analysis by logistic fit, computerized tomography visible structure predicted increased stone fragility with an overall area under the ROC curve of 0.64. The shock wave lithotripsy fragility of brushite stones did not correlate with internal structure discernible on helical computerized tomography. However, fragility did correlate with stone density and increasing brushite mineral content, consistent with clinical experience with patients with brushite calculi. Thus, current diagnostic computerized tomography technology does not provide a means to predict when brushite stones will break well using shock wave lithotripsy.

Internal Structure and Assemblage Features of Tectonic Slices in Dong Cuo Melange Zone

In order to make a thorough study of the Dong Cuo melange zone,the authors used remote sensing interpretation to divide the Dong Cuo melange zone into three secondary tectonic slices belts,and found that the three belts extend nearly in parallel in the plane,converge eastward and westward,and thrust southward one by one in profile.Field investigation shows that the interpretation results are in accordance with the practical situation,and the material composition and geometric structure of rocks in various slices are different.The ophiolite melange belt is the main belt in the Dong Cuo melange zone.

2187 BRUSHITE STONE FRAGILITY IN SHOCK WAVE LITHOTRIPSY IS NOT PREDICTED BY CT VISIBLE STRUCTURE OR HOUNSFIELD UNITS

You have accessJournal of UrologyImaging/Radiology: Uroradiology II1 Apr 20122187 BRUSHITE STONE FRAGILITY IN SHOCK WAVE LITHOTRIPSY IS NOT PREDICTED BY CT VISIBLE STRUCTURE OR HOUNSFIELD UNITS James Williams, Tariq Hameed, Syed Aftab, James Lingeman, and James McAteer James WilliamsJames Williams Indianapolis, IN More articles by this author , Tariq HameedTariq Hameed Indianapolis, IN More articles by this author , Syed AftabSyed Aftab Indianapolis, IN More articles by this author , James LingemanJames Lingeman Indianapolis, IN More articles by this author , and James McAteerJames McAteer Indianapolis, IN More articles by this author View All Author Informationhttps://doi.org/10.1016/j.juro.2012.02.2361AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookTwitterLinked InEmail INTRODUCTION AND OBJECTIVES Brushite stones are challenging as they recur frequently and are often resistant to breakage by shock wave lithotripsy (SWL). With other stone types it has been shown in laboratory studies that visibility of structure in stones using helical computed tomography (helical CT) correlates with easier breakage with SWL. The objective of this study was to test brushite stones for similar correlation of stone fragility with internal stone structure visible by CT. METHODS Fifty-two brushite stones, ranging in size from 5 to 12 mm, were scanned by micro CT, weighed, hydrated, and placed within a saline radiological phantom containing 3% iodine to emulate body tissue. The stones were scanned using a 256-slice Brilliance iCT scanner (Philips Healthcare), and the images evaluated for visibility of internal structural features. The stones were then treated by SWL in vitro, and the number of SWs needed to break each stone to completion (fragments < 2 mm) was recorded. Fragments were analyzed using IR spectroscopy to assess stone mineral purity. RESULTS The number of SWs to break each stone, normalized to stone weight, did not differ by Hounsfield unit value (P=0.84), or CT-visible structure that could be identified consistently (unanimous opinion only, P =0.053) by all observers; however, observer agreement was low (kappa=0.3) in the identification of CT-visible structure. Fragility of stones was highly correlated with stone density and with brushite content (both P <0.001), with stones of nearly pure brushite requiring the most SWs to break. When all observations of CT-visible structure were used in analysis by logistic fit, there was poor correlation between stone structure and fragility, with low sensitivity (0.62), low specificity (0.51), and an overall area under the receiver operating characteristic (ROC) curve of only 0.64. CONCLUSIONS SWL fragility of brushite stones did not correlate with internal structure discernable using helical CT. However, fragility did correlate with stone density and increasing brushite mineral content, which is consistent with clinical experience with brushite stone patients. Thus, current technology in diagnostic CT does not provide a means to predict if brushite stones will break well using SWL. © 2012 by American Urological Association Education and Research, Inc.FiguresReferencesRelatedDetails Volume 187Issue 4SApril 2012Page: e882 Peer Review Report Advertisement Copyright & Permissions© 2012 by American Urological Association Education and Research, Inc.MetricsAuthor Information James Williams Indianapolis, IN More articles by this author Tariq Hameed Indianapolis, IN More articles by this author Syed Aftab Indianapolis, IN More articles by this author James Lingeman Indianapolis, IN More articles by this author James McAteer Indianapolis, IN More articles by this author Expand All Advertisement Advertisement PDF downloadLoading ...

Structure of Titin PEVK Explored with FRET Spectroscopy

The PEVK domain of the giant muscle protein titin is largely responsible for molecular extensibility within the physiological sarcomere-length range. Although the domain is thought to be an intrinsically unstructured random-coil structure, several observations suggest that it may not be completely devoid of internal interactions and structural features. To test the validity of random polymer models for PEVK, here we measured the contour-length scaling of the equilibrium mean end-to-end distance of synthetic PEVK peptides with FRET (Forster's Resonance Energy Transfer) spectroscopy. Mean end-to-end distances of an 11- and a 21-residue PEVK peptide were calculated from the energy transfer efficiency between an intrinsic tryptophan donor and a synthetically added IAEDANS acceptor positioned on the N- and C-termini, respectively. We find that the contour-length scaling of mean end-to-end distance deviates from the square-root law predicted for a purely statistical polymer chain. Addition of guanidine-HCl increased, whereas the addition of salt decreased the mean end-to-end distance, indicating that both H-bonding and electrostatic interactions play role in stabilizing PEVK structure. Increasing temperature between 5-50 °C resulted in monotonous increase in FRET efficiency, suggesting that PEVK may pass through multiple conformational states separated by small energy barriers. Simulations suggest that the residual structures are loose helical configurations. Varying the distribution across these states may tune the apparent local elasticity along the PEVK domain and modulate the dynamics of passive muscle force generation.Supported by a grant from the Hungarian National Development Agency, TAMOP-4.2.1.B-09/1/KMR-2010-0001.

What should be the characteristics of the ideal bone graft substitute? Combining scaffolds with growth factors and/or stem cells

Reconstruction of large bone defects or non-unions resulting from biochemical disorders, tumour resections or complicated fractures is still a challenge for orthopaedic and trauma surgery. On the one hand, autografts harbour most features of ideal bone graft substitutes but on the other hand, they have a lot insurmountable disadvantages. An ideal bone graft substitute should be biomechanically stable, able to degrade within an appropriate time frame, exhibit osteoconductive, osteogenic and osteoinductive properties and provide a favourable environment for invading blood vessels and bone forming cells. Whilst osteoconductivity of biomaterials for bone tissue engineering strategies can be directed by their composition, surface character and internal structure, osteoinductive and osteogenic features can be provided by growth factors originally participating in fracture healing and/or multipotent mesenchymal stromal/stem cells (MSC) capable of rebuilding bone and marrow structures. In this review, aspects of the clinical application of the most commonly used growth factors for bone repair, the bone morphogenetic proteins (BMPs), and the potential use of human MSC for clinical application will be discussed.

Arctic Clothing of North America: Alaska, Canada, Greenland by J.C.H. King, Birgit Pauksztat, and Robert Storrie

Arctic Clothing of North America: Alaska, Canada, Greenland by J.C.H. King, Birgit Pauksztat, and Robert Storrie

End-Bridging Monte Carlo Simulation of Bulk and Grafted Amorphous Polyethylene Above and Below the Glass Transition

The very efficient end-bridging Monte Carlo (EBMC) method has been employed in order to simulate an amorphous, polydisperse 80-chain large C156 polyethylene (PE) system in atomistic detail over a wide range of temperatures (from 600 down to 150 K) and determine its glass transition temperature (Tg). Two sets of simulations have been performed: one with a bulk, isotropic sample and the other with a thin film in which all the 80 PE chains were grafted on a hard substrate on one side (corresponding to a high grafting density equal to σ = 1.75 nm-2) and exposed to vacuum on the other side. In the simulations, a united-atom model was employed for PE ensuring that only the purely amorphous phase of PE was simulated at all temperatures. In all cases, very long simulations were carried out in order to give enough time for the system to relax at all length scales. For all temperatures studied, the longest relaxation time was found to be present by descriptors associated with the system's long-range conformational characteristics. In contrast, more local, internal structural features were always faster in equilibrating. As a result, the time autocorrelation function for the chain end-to-end unit vector, fu(t), was found to drop to zero and then clearly fluctuate around this value only for temperatures higher than about 220 K for both systems. For lower temperatures, fu(t) did not relax completely, even after 2 × 107 CPU seconds. Additional volumetric simulation data demonstrated a sharp change in the density and potential energy of both systems in the neighborhood of the 230 K, which are considered as features of the glass transition for amorphous PE. The Tg value suggested by the present EBMC simulations for amorphous (bulk or grafted) PE is (230 ± 10) K, which is consistent with the value of 237 K measured experimentally by Wunderlich [J. of Chem. Phys. 1962, 37, 1203] and Loufakis and Wunderlich [J. Phys. Chem. 1988, 92, 4205] for PE in the limit of zero crystallinity. Further, the predicted change in the heat capacity at constant pressure at the glass transition is Δcp = 1.2 × 10-4 kcal g-1 K-1, which is very close to the value of 1.5 × 10-4 kcal g-1 K-1 measured experimentally by Wunderlich [J. of Chem. Phys. 1962, 37, 1203]. Additional results on the temperature dependence of the conformational and structural properties in the two PE systems are also reported and discussed in detail.