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https://www.readbyqxmd.com/read/28436921/feasibility-study-of-entrance-and-exit-dose-measurements-at-the-contra-lateral-breast-with-alanine-electron-spin-resonance-dosimetry-in-volumetric-modulated-radiotherapy-of-breast-cancer
#1
Daniela M Wagner, Petra Huettenrauch, Mathias Anton, Philip von Voigts-Rhetz, Klemens Zink, Hendrik Wolff
PURPOSE: The Physikalisch-Technische Bundesanstalt (PTB) has established a secondary standard measurement system for the dose to water, DW, based on alanine/ ESR (Anton et. al. 2013). The aim of this study was to test the established measurements system for out of field measurements inpatient with breast cancer. METHOD AND MATERIALS: A set of five alanine pellets were affixed to each patients` skin at the contra lateral breast beginning at the sternum and extending over the mammilla to the distal surface...
April 24, 2017: Physics in Medicine and Biology
https://www.readbyqxmd.com/read/28434642/-late-life-depression-or-prodromal-alzheimer-s-disease-which-tools-for-the-differential-diagnosis
#2
A-I Gasser, V Salamin, S Zumbach
INTRODUCTION: Depression and Alzheimer's disease are both very frequent in elderly people. Cognitive deficits are the hallmark of Alzheimer's disease, but they are also common in depressed elderly people who often present cognitive deficits such as memory, attention and executive function problems. On the other hand, people with early Alzheimer's disease demonstrate emotional and behavioral disorders generally encountered in depression such as loss of energy, apathy, mood disorder, and irritability...
April 20, 2017: L'Encéphale
https://www.readbyqxmd.com/read/28431860/predictive-value-of-perfusion-defects-on-dual-energy-cta-in-the-absence-of-thromboembolic-clots
#3
Richard A P Takx, Thomas Henzler, U Joseph Schoepf, Thomas Germann, Stefan O Schoenberg, Aysel Shirinova, Ralf W Bauer, Claudia Frellesen, Long Jiang Zhang, John W Nance, Christian Fink, Paul Apfaltrer
BACKGROUND: To determine the predictive value of volumetrically measured lung perfusion defects (PDvol) and right ventricular dysfunction on dual-energy computed tomography angiography (DE-CTA) for predicting all cause mortality in patients suspected of pulmonary embolism (PE) but without evident thromboembolic clot on CTA. METHODS: 448 patients underwent DE-CTA on a 64-channel DSCT system between January 2007 and December 2012 for suspected PE, of which 115 were without detectable thromboembolic clot on CTA...
April 18, 2017: Journal of Cardiovascular Computed Tomography
https://www.readbyqxmd.com/read/28430345/healing-response-of-rat-pulp-treated-with-an-injectable-keratin-hydrogel
#4
Lavanya Ajay Sharma, Robert M Love, Mohammad A Ali, Ajay Sharma, Soraia Macari, Avadhoot Avadhani, George J Dias
BACKGROUND: Keratin has shown promising outcomes as a biomaterial due to its inherent bioactivity, biocompatibility and regenerative effects. The effect of keratin on repair and regeneration of dental tissues has never been studied before. Current therapies to treat pulp tissues involve its replacement with inert, synthetic materials that do not have a proper biological function, leading to failure and tooth loss. This study aimed to develop a biocompatible keratin hydrogel (KH) suitable for pulp therapies...
April 20, 2017: Journal of Applied Biomaterials & Functional Materials
https://www.readbyqxmd.com/read/28418651/electrodeposition-of-highly-porous-pt-nanoparticles-studied-by-quantitative-3d-electron-tomography-influence-of-growth-mechanisms-and-potential-cycling-on-the-active-surface-area
#5
Jon Ustarroz, Bart Geboes, Hans Vanrompay, Kadir Sentosun, Sara Bals, Tom Breugelmans, Annick Hubin
Nanoporous Pt nanoparticles (NPs) are promising fuel cell catalysts due to their large surface area and increased electrocatalytic activity towards the oxygen reduction reaction (ORR). Herein, we report on the influence of the growth mechanisms on the surface properties of electrodeposited Pt dendritic NPs with large surface areas. The electrochemically active surface was studied by hydrogen underpotential deposition (H UPD) and compared for the first time to high angle annular dark field scanning transmission electron microscopy (HAADF-STEM) quantitative 3D electron tomography of individual nanoparticles...
April 18, 2017: ACS Applied Materials & Interfaces
https://www.readbyqxmd.com/read/28416317/zinc-oxide-inhibits-dental-discoloration-caused-by-white-mineral-trioxide-aggregate-angelus
#6
Marina Angélica Marciano, Josette Camilleri, Reginaldo Mendonça Costa, Mariza Akemi Matsumoto, Bruno Martini Guimarães, Marco Antonio Hungaro Duarte
INTRODUCTION: The aim of the study was to investigate the addition of variable amounts of zinc oxide to inhibit dental discoloration caused by mineral trioxide aggregate (MTA) Angelus. METHODS: MTA Angelus and MTA with additions of 5%, 15%, and 45% zinc oxide (ZnO) in weight were tested. The set cements were characterized by using a combination of scanning electron microscopy, energy dispersive spectroscopy, and x-ray diffraction. Radiopacity and setting time were analyzed according to American National Standards Institute/American Dental Association (57/2012) and American Society for Testing and Materials (C266-08)...
April 14, 2017: Journal of Endodontics
https://www.readbyqxmd.com/read/28416035/measuring-the-autocorrelation-function-of-nanoscale-three-dimensional-density-distribution-in-individual-cells-using-scanning-transmission-electron-microscopy-atomic-force-microscopy-and-a-new-deconvolution-algorithm
#7
Yue Li, Di Zhang, Ilker Capoglu, Karl A Hujsak, Dhwanil Damania, Lusik Cherkezyan, Eric Roth, Reiner Bleher, Jinsong S Wu, Hariharan Subramanian, Vinayak P Dravid, Vadim Backman
Essentially all biological processes are highly dependent on the nanoscale architecture of the cellular components where these processes take place. Statistical measures, such as the autocorrelation function (ACF) of the three-dimensional (3D) mass-density distribution, are widely used to characterize cellular nanostructure. However, conventional methods of reconstruction of the deterministic 3D mass-density distribution, from which these statistical measures can be calculated, have been inadequate for thick biological structures, such as whole cells, due to the conflict between the need for nanoscale resolution and its inverse relationship with thickness after conventional tomographic reconstruction...
April 18, 2017: Microscopy and Microanalysis
https://www.readbyqxmd.com/read/28414801/probabilistic-fluorescence-based-synapse-detection
#8
Anish K Simhal, Cecilia Aguerrebere, Forrest Collman, Joshua T Vogelstein, Kristina D Micheva, Richard J Weinberg, Stephen J Smith, Guillermo Sapiro
Deeper exploration of the brain's vast synaptic networks will require new tools for high-throughput structural and molecular profiling of the diverse populations of synapses that compose those networks. Fluorescence microscopy (FM) and electron microscopy (EM) offer complementary advantages and disadvantages for single-synapse analysis. FM combines exquisite molecular discrimination capacities with high speed and low cost, but rigorous discrimination between synaptic and non-synaptic fluorescence signals is challenging...
April 17, 2017: PLoS Computational Biology
https://www.readbyqxmd.com/read/28412573/patient-characteristics-associated-with-differences-in-radiation-exposure-from-pediatric-abdomen-pelvis-ct-scans-a-quantile-regression-analysis
#9
Jennifer N Cooper, Daniel L Lodwick, Brent Adler, Choonsik Lee, Peter C Minneci, Katherine J Deans
BACKGROUND: Computed tomography (CT) is a widely used diagnostic tool in pediatric medicine. However, due to concerns regarding radiation exposure, it is essential to identify patient characteristics associated with higher radiation burden from CT imaging, in order to more effectively target efforts towards dose reduction. Our objective was to identify the effects of various demographic and clinical patient characteristics on radiation exposure from single abdomen/pelvis CT scans in children...
April 12, 2017: Computers in Biology and Medicine
https://www.readbyqxmd.com/read/28412289/structural-studies-of-the-endogenous-spliceosome-the-supraspliceosome
#10
REVIEW
Joseph Sperling, Ruth Sperling
Pre-mRNA splicing is executed in mammalian cell nuclei within a huge (21 MDa) and highly dynamic molecular machine - the supraspliceosome - that individually package pre-mRNA transcripts of different sizes and number of introns into complexes of a unique structure, indicating their universal nature. Detailed structural analysis of this huge and complex structure requires a stepwise approach using hybrid methods. Structural studies of the supraspliceosome by room temperature electron tomography, cryo-electron tomography, and scanning transmission electron microscope mass measurements revealed that it is composed of four native spliceosomes, each resembling an in vitro assembled spliceosome, which are connected by the pre-mRNA...
April 12, 2017: Methods: a Companion to Methods in Enzymology
https://www.readbyqxmd.com/read/28411510/compressed-sensing-for-stem-tomography
#11
Laurène Donati, Masih Nilchian, Sylvain Trépout, Cédric Messaoudi, Sergio Marco, Michael Unser
A central challenge in scanning transmission electron microscopy (STEM) is to reduce the electron radiation dosage required for accurate imaging of 3D biological nano-structures. Methods that permit tomographic reconstruction from a reduced number of STEM acquisitions without introducing significant degradation in the final volume are thus of particular importance. In random-beam STEM (RB-STEM), the projection measurements are acquired by randomly scanning a subset of pixels at every tilt view. In this work, we present a tailored RB-STEM acquisition-reconstruction framework that fully exploits the compressed sensing principles...
April 6, 2017: Ultramicroscopy
https://www.readbyqxmd.com/read/28411364/centriolar-remodeling-underlies-basal-body-maturation-during-ciliogenesis-in-caenorhabditis-elegans
#12
Inna V Nechipurenko, Cristina Berciu, Piali Sengupta, Daniela Nicastro
The primary cilium is nucleated by the mother centriole-derived basal body (BB) via as yet poorly characterized mechanisms. BBs have been reported to degenerate following ciliogenesis in the C. elegans embryo, although neither BB architecture nor early ciliogenesis steps have been described in this organism. In a previous study (Doroquez et al., 2014), we described the three-dimensional morphologies of sensory neuron cilia in adult C. elegans hermaphrodites at high resolution. Here, we use serial section electron microscopy and tomography of staged C...
April 15, 2017: ELife
https://www.readbyqxmd.com/read/28411189/centrioles-initiate-cilia-assembly-but-are-dispensable-for-maturation-and-maintenance-in-c-elegans
#13
Daniel Serwas, Tiffany Y Su, Max Roessler, Shaohe Wang, Alexander Dammermann
Cilia are cellular projections that assemble on centriole-derived basal bodies. While cilia assembly is absolutely dependent on centrioles, it is not known to what extent they contribute to downstream events. The nematode C. elegans provides a unique opportunity to address this question, as centrioles do not persist at the base of mature cilia. Using fluorescence microscopy and electron tomography, we find that centrioles degenerate early during ciliogenesis. The transition zone and axoneme are not completely formed at this time, indicating that cilia maturation does not depend on intact centrioles...
April 14, 2017: Journal of Cell Biology
https://www.readbyqxmd.com/read/28410679/dual-energy-imaging-method-to-improve-the-image-quality-and-the-accuracy-of-dose-calculation-for-cone-beam-computed-tomography
#14
Kuo Men, Jianrong Dai, Xinyuan Chen, Minghui Li, Ke Zhang, Peng Huang
PURPOSE: To improve the image quality and accuracy of dose calculation for cone-beam computed tomography (CT) images through implementation of a dual-energy cone-beam computed tomography method (DE-CBCT), and evaluate the improvement quantitatively. METHODS: Two sets of CBCT projections were acquired using the X-ray volumetric imaging (XVI) system on a Synergy (Elekta, Stockholm, Sweden) system with 120kV (high) and 70kV (low) X-rays, respectively. Then, the electron density relative to water (relative electron density (RED)) of each voxel was calculated using a projection-based dual-energy decomposition method...
April 2017: Physica Medica: PM
https://www.readbyqxmd.com/read/28408757/defect-induced-luminescence-quenching-vs-charge-carrier-generation-of-phosphorus-incorporated-in-silicon-nanocrystals-as-function-of-size
#15
Daniel Hiller, Julian López-Vidrier, Sebastian Gutsch, Margit Zacharias, Keita Nomoto, Dirk König
Phosphorus doping of silicon nanostructures is a non-trivial task due to problems with confinement, self-purification and statistics of small numbers. Although P-atoms incorporated in Si nanostructures influence their optical and electrical properties, the existence of free majority carriers, as required to control electronic properties, is controversial. Here, we correlate structural, optical and electrical results of size-controlled, P-incorporating Si nanocrystals with simulation data to address the role of interstitial and substitutional P-atoms...
April 13, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28402967/surface-curvature-in-triply-periodic-minimal-surface-architectures-as-a-distinct-design-parameter-in-preparing-advanced-tissue-engineering-scaffolds
#16
Sébastien B G Blanquer, Maike Werner, Markus Hannula, Shahriar Sharifi, Guillaume P R Lajoinie, David Eglin, Jari Hyttinen, André A Poot, Dirk W Grijpma
Reproduction of the anatomical structures and functions of tissues using cells and designed 3D scaffolds is an ongoing challenge. For this, scaffolds with appropriate biomorphic surfaces promoting cell attachment, proliferation and differentiation are needed. In this study, eight triply-periodic minimal surface (TPMS)-based scaffolds were designed using specific trigonometric equations, providing the same porosity and the same number of unit cells, while presenting different surface curvatures. The scaffolds were fabricated by stereolithography using a photocurable resin based on the biocompatible, biodegradable and rubber-like material, poly(trimethylene carbonate) (PTMC)...
April 12, 2017: Biofabrication
https://www.readbyqxmd.com/read/28401897/label-free-volumetric-optical-imaging-of-intact-murine-brains
#17
Jian Ren, Heejin Choi, Kwanghun Chung, Brett E Bouma
A central effort of today's neuroscience is to study the brain's 'wiring diagram'. The nervous system is believed to be a network of neurons interacting with each other through synaptic connection between axons and dendrites, therefore the neuronal connectivity map not only depicts the underlying anatomy, but also has important behavioral implications. Different approaches have been utilized to decipher neuronal circuits, including electron microscopy (EM) and light microscopy (LM). However, these approaches typically demand extensive sectioning and reconstruction for a brain sample...
April 12, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28398001/an-update-on-carbon-nanotube-enabled-x-ray-sources-for-biomedical-imaging
#18
REVIEW
Connor Puett, Christina Inscoe, Allison Hartman, Jabari Calliste, Dora K Franceschi, Jianping Lu, Otto Zhou, Yueh Z Lee
A new imaging technology has emerged that uses carbon nanotubes (CNT) as the electron emitter (cathode) for the X-ray tube. Since the performance of the CNT cathode is controlled by simple voltage manipulation, CNT-enabled X-ray sources are ideal for the repetitive imaging steps needed to capture three-dimensional information. As such, they have allowed the development of a gated micro-computed tomography (CT) scanner for small animal research as well as stationary tomosynthesis, an experimental technology for large field-of-view human imaging...
April 11, 2017: Wiley Interdisciplinary Reviews. Nanomedicine and Nanobiotechnology
https://www.readbyqxmd.com/read/28397977/methodological-accuracy-of-image-based-electron-density-assessment-using-dual-energy-computed-tomography
#19
Christian Möhler, Patrick Wohlfahrt, Christian Richter, Steffen Greilich
PURPOSE: Electron density is the most important tissue property influencing photon and ion dose distributions in radiotherapy patients. Dual-energy computed tomography (DECT) enables the determination of electron density by combining the information on photon attenuation obtained at two different effective x-ray energy spectra. Most algorithms suggested so far use the CT numbers provided after image reconstruction as input parameters, i.e. are imaged-based. To explore the accuracy that can be achieved with these approaches, we quantify the intrinsic methodological and calibration uncertainty of the seemingly simplest approach...
April 11, 2017: Medical Physics
https://www.readbyqxmd.com/read/28397274/does-incidental-mastoid-opacification-on-computerized-tomography-necessitate-referral-to-ent
#20
Sophie L Wilkinson, Raguwinder S Sahota, James D Constable, Frazer Harper, Owen Judd
OBJECTIVE: The prevalence of incidental temporal bone disease on magnetic resonance imaging has been widely reported in the medical literature. Despite this, there currently is little evidence regarding incidental otological disease on computerized tomography (CT). Thus, the study aimed to review the CT prevalence of asymptomatic adult ear disease and evaluate the appropriateness of ear, nose, and throat (ENT) referral following its discovery. STUDY DESIGN: Retrospective observational study of 468 CT scans...
April 11, 2017: Laryngoscope
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