scholarly journals Integration of Dental Implants in Conjunction with EDTA-Conditioned Dentin Grafts: An Experimental Study

2021 ◽  
Vol 9 (6) ◽  
pp. 63
Author(s):  
Payam Farzad ◽  
Ted Lundgren ◽  
Adel Al-Asfour ◽  
Lars Andersson ◽  
Christer Dahlin
Keyword(s):  
Direct Contact ◽  
Mineral Content ◽  
X Rays ◽  
X Ray ◽  
Dentin Surface ◽  
Significant Difference ◽  
C And N ◽  
Micro Implants ◽  
Demineralized Dentin

This study was undertaken to investigate the integration of titanium micro-implants installed in conjunction with previously dentin-grafted areas and to study the morphological appearance, mineral content, and healing pattern of xenogenic EDTA-conditioned dentin blocks and granules grafted to cavities in the tibial bone of rabbits. Demineralized and non-demineralized dentin blocks and granules from human premolars were implanted into cavities prepared on the lateral aspects of the tibias of rabbits. After a healing period of six months, micro-implants were installed at each surgical site. Histological examinations were carried out after 24 weeks. Characterization of the EDTA-conditioned dentin blocks was performed by means of light microscopy, dental X-rays, scanning electron microscopy, and energy dispersive X-ray analysis (EDX). No implants were found to be integrated in direct contact with the dentin particles or blocks. On the EDTA-conditioned dentin surface, the organic marker elements C and N dominated, as revealed by EDX. The hydroxyapatite constituents Ca and P were almost absent on the dentin surface. No statistically significant difference was observed between the EDTA-conditioned and non-demineralized dentin, as revealed by BIC and BA. The bone-inductive capacity of the dentin material seemed limited, although demineralization by means of EDTA indicated higher BIC and BA values in conjunction with the installed implants in the area. A 12 h EDTA treatment did not fully decalcify the grafts, as revealed by X-ray analysis.

Digital x-ray mapping of nanometer-size supported bimetallic catalysts

1988 ◽  
Vol 46 ◽  
pp. 530-531
Author(s):  
L. T. Germinario
Keyword(s):  
Background Radiation ◽  
Metal Cluster ◽  
Single Element ◽  
Beam Diameter ◽  
X Rays ◽  
X Ray ◽  
Major Interest ◽  
Induced Changes

Understanding the role of metal cluster composition in determining catalytic selectivity and activity is of major interest in heterogeneous catalysis. The electron microscope is well established as a powerful tool for ultrastructural and compositional characterization of support and catalyst. Because the spatial resolution of x-ray microanalysis is defined by the smallest beam diameter into which the required number of electrons can be focused, the dedicated STEM with FEG is the instrument of choice. The main sources of errors in energy dispersive x-ray analysis (EDS) are: (1) beam-induced changes in specimen composition, (2) specimen drift, (3) instrumental factors which produce background radiation, and (4) basic statistical limitations which result in the detection of a finite number of x-ray photons. Digital beam techniques have been described for supported single-element metal clusters with spatial resolutions of about 10 nm. However, the detection of spurious characteristic x-rays away from catalyst particles produced images requiring several image processing steps.

The influence of X-ray coherence length on TXRF and XSW and the characterization of nanoparticles observed under grazing incidence of X-rays

2009 ◽  
Vol 24 (6) ◽  
pp. 792 ◽  
Author(s):  
Alex von Bohlen ◽  
Markus Krämer ◽  
Christian Sternemann ◽  
Michael Paulus
Keyword(s):  
Coherence Length ◽  
Grazing Incidence ◽  
X Rays ◽  
X Ray

X-RAY DIFFRACTION FOR SURFACES AND BURIED INTERFACES

2000 ◽  
Vol 07 (04) ◽  
pp. 437-446 ◽  
Author(s):  
G. RENAUD
Keyword(s):  
Grazing Incidence ◽  
X Rays ◽  
X Ray Diffraction ◽  
X Ray ◽  
Grain Sizes ◽  
Buried Interfaces ◽  
Surfaces And Interfaces ◽  
Coherent Interfaces

The application of X-rays to the structural characterization of surfaces and interfaces, in situ and in UHV, is discussed on selected examples. Grazing incidence X-ray diffraction is not only a very powerful technique for quantitatively investigating the atomic structure of surfaces and interfaces, but is also very useful for providing information on the interfacial registry for coherent interfaces or on the strain deformation, island and grain sizes for incoherent epilayers.

scholarly journals Closing the gap between electron and X-ray crystallography

2015 ◽  
Vol 71 (6) ◽  
pp. 737-739 ◽  
Author(s):  
Enrico Mugnaioli
Keyword(s):  
Electron Diffraction ◽  
Structure Characterization ◽  
Diffraction Tomography ◽  
X Rays ◽  
Electron Crystallography ◽  
X Ray ◽  
X Ray Crystallography ◽  
Closing The Gap ◽  
Refinement Algorithm

The development of a proper refinement algorithm that takes into account dynamical scattering guarantees, for electron crystallography, results approaching X-rays in terms of precision, accuracy and reliability. The combination of such dynamical refinement and electron diffraction tomography establishes a complete pathway for the structure characterization of single sub-micrometric crystals.

scholarly journals NuSTAR reveals that the heavily obscured nucleus of NGC 2785 was the contaminant of IRAS 09104+4109 in the BeppoSAX/PDS hard X-rays

2018 ◽  
Vol 619 ◽  
pp. A16
Author(s):  
C. Vignali ◽  
P. Severgnini ◽  
E. Piconcelli ◽  
G. Lanzuisi ◽  
R. Gilli ◽  
...  
Keyword(s):  
X Rays ◽  
X Ray ◽  
Star Forming ◽  
Physical Description ◽  
Enhanced Sensitivity ◽  
X Ray Imaging ◽  
First Time ◽  
In Virtue Of

Context. The search for heavily obscured active galactic nuclei has been revitalized in the last five years by NuSTAR, which has provided a good census and spectral characterization of a population of such objects, mostly at low redshift, thanks to its enhanced sensitivity above 10 keV compared to previous X-ray facilities, and its hard X-ray imaging capabilities. Aims. We aim at demonstrating how NGC 2785, a local (z = 0.009) star-forming galaxy, is responsible, in virtue of its heavily obscured active nucleus, for significant contamination in the non-imaging BeppoSAX/PDS data of the relatively nearby (≈17′) quasar IRAS 09104+4109 (z = 0.44), which was originally mis-classified as Compton thick. Methods. We analyzed ≈71 ks NuSTAR data of NGC 2785 using the MYTorus model and provided a physical description of the X-ray properties of the source for the first time. Results. We found that NGC 2785 hosts a heavily obscured (NH ≈ 3 × 1024 cm−2) nucleus. The intrinsic X-ray luminosity of the source, once corrected for the measured obscuration (L2−10keV ≈ 1042 erg s−1), is consistent within a factor of a few with predictions based on the source mid-infrared flux using widely adopted correlations from the literature. Conclusions. Based on NuSTAR data and previous indications from the Neil Gehrels Swift Observatory (BAT instrument), we confirm that NGC 2785, because of its hard X-ray emission and spectral shape, was responsible for at least one third of the 20–100 keV emission observed using the PDS instrument onboard BeppoSAX, originally completely associated with IRAS 09104+4109. Such emission led to the erroneous classification of this source as a Compton-thick quasar, while it is now recognized as Compton thin.

Preparation of Local Raw Material for α-Fe2O3 Nanoparticles Powder from Mineral Extraction of Iron Sand

2019 ◽  
Vol 966 ◽  
pp. 308-313
Author(s):  
M.P. Izaak ◽  
H. Sitompul ◽  
Wisnu Ari Adi ◽  
Yohanes Edi Gunanto
Keyword(s):  
Mineral Content ◽  
High Energy ◽  
Coprecipitation Method ◽  
Raw Material ◽  
X Ray ◽  
Size Characterization ◽  
Coercivity Field ◽  
Average Size ◽  
Particle Size Characterization

Synthesis and characterization of α-Fe2O3 nanoparticles were obtained from extraction of ilmenite iron sand with coprecipitation method and to obtain α-Fe2O3 nanoparticles, high energy milling (HEM) was used. Surface morphology and identification of the elements contained in the sample were analyzed using scanning electron microscope (SEM) and energy dispersive spectroscopy (EDS). For phase analysis and crystal structure, X-ray diffractometer (XRD) was used. Moreover a vibrating magnetometer sample (VSM) was used to characterize its magnetic properties, while tunneling electron microscopy (TEM) was used for particle size characterization. Ilmenite-type iron sand has a diverse particle shape with a size of more than 100 μm with ilmenite (FeTiO3) mineral content of about 64.7%. The results of extraction using coprecipitation method with sintering 750 °C, obtained hematite α-Fe2O3 material which has not been saturated to an external magnetic field of 1 tesla, the magnetic remanent value (Mr) is about 0.8 emu/g and the coercivity field value is Hc around 773 Oe. The average size of hematite α-Fe2O3 particles after being milled 50 hours is between 15-30 nm with a cube-like shape.

scholarly journals Reproducibility of pixel values for two photostimulable phosphor plates in consecutive standardized scannings

2006 ◽  
Vol 20 (3) ◽  
pp. 207-213 ◽  
Author(s):  
Patrícia Freitas ◽  
Renato Yassutaka Faria Yaedú ◽  
Izabel Regina Fischer Rubira-Bullen ◽  
Maurício Escarpinati ◽  
Marcelo Costa Vieira ◽  
...  
Keyword(s):  
Digital Image ◽  
X Rays ◽  
X Ray ◽  
Scanning Time ◽  
Quantitative Studies ◽  
Significant Difference ◽  
Photostimulable Phosphor ◽  
Phosphor Plates

The objective of the present study was to determine the reproducibility of the pixel values obtained with the Digora system (Soredex, Finland). Exposures were standardized, with variation in exposure and scanning time of two photostimulable phosphor plates containing a stepwedge image. The smallest variation in pixel values ranged from 50 to 75%, with the widest variations being observed in less dense steps. A significant difference in pixel values was observed in terms of X-ray exposure and scanning times and between the two plates themselves (ANOVA, p < 0.01). Using the present methodology, the reproducibility of pixel values was not satisfactory for the tested white photostimulable plates. This wide variation in digitalization might be influenced by the amount of X-rays that sensitized the plates. It may be important to establish the reproducibility of the pixel values in quantitative studies using digital image.

POSITRON FACILITIES TESTS OF THE X-RAYS PRODUCED BY CRYSTALLINE UNDULATORS

2005 ◽  
Vol 19 (03) ◽  
pp. 85-98 ◽  
Author(s):  
S. BELLUCCI
Keyword(s):  
Positron Beam ◽  
Precise Determination ◽  
X Rays ◽  
Experimental Conditions ◽  
X Ray ◽  
Accelerated Particles

One of the main involvements of the INFN-Laboratori Nazionali di Frascati group in channeling researches is described, i.e. the crystal undulator R & D, with the characterization of the crystal undulator prototypes with SEM and the positron beam. We consider a precise determination of the optimal experimental conditions for channeling of this kind of accelerated particles through such microstructured crystals, as promising candidates for producing X-ray beams.

Nanofabrication and characterization of a grating-based condenser for uniform illumination with hard X-rays

2017 ◽  
Vol 24 (3) ◽  
pp. 595-599
Author(s):  
Jianpeng Liu ◽  
Xin Li ◽  
Shuo Chen ◽  
Sichao Zhang ◽  
Shanshan Xie ◽  
...  
Keyword(s):  
Finite Difference Time Domain ◽  
Optical Characterization ◽  
X Rays ◽  
Uniform Illumination ◽  
Basic Study ◽  
Full Field ◽  
X Ray ◽  
High Uniformity ◽  
Difference Time

In the development of full-field transmission X-ray microscopy for basic study in science and technology, a condenser capable of providing intense illumination with high uniformity and stability on tested specimens in order to achieve high-quality images is essential. The latest design of a square-shaped condenser based on diffractive gratings has demonstrated promising uniformity in illumination. This paper describes in more detail the development of such a beam shaper for hard X-rays at 10 keV with regard to its design, manufacture and optical characterization. The effect of the grating profile on the diffracted intensity has been theoretically predicted by numerical simulation using the finite-difference time-domain method. Based on this, the limitations of the grating-based condenser are discussed.

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