Characterization of the Human Junctional Epithelial Cells Directly Attached to the Tooth (DAT Cells)in Periodontal Disease

1994 ◽  
Vol 73 (12) ◽  
pp. 1818-1823 ◽  
Author(s):  
D.O. Overman ◽  
J.I. Salonen
Keyword(s):  
Periodontal Disease ◽  
Tooth Surface ◽  
Junctional Epithelium ◽  
Transmission Electron ◽  
The Individual ◽  
Pocket Formation ◽  
Resistant Structure ◽  
Proliferative Ability

This study examined the directly attached cells (DAT cells) of the human junctional epithelium from teeth extracted for advanced periodontal disease. The monolayer nature of the DAT cells remaining on the tooth surface after extraction offers a unique opportunity to study their morphology and activity in situ. We collected DAT cells and examined them by transmission electron microscopy and by autoradiography of cells labeled with 3H-thymidine. Our morphological results suggest that degenerative changes associated with pocket formation affect individual cells rather than regions of the DAT cell population at one time. The epithelial attachment apparatus (EAA) appeared to be the most resistant structure persisting on the tooth surface during the degeneration of the individual DAT cells. The new technique developed for two-dimensional observation of the sheet of DAT cells labeled in situ on the tooth surface in culture showed that the attached cells, even in periodontal disease, exhibit proliferative ability, suggesting a regenerative role for the DAT cells.

The Use of Advanced Analytical Techniques for Characterization of the Chemical, Physical, and Crystallographic Nature of a Surface

1973 ◽  
Vol 31 ◽  
pp. 132-133 ◽  
Author(s):  
R. E. Herfert
Keyword(s):  
Surface Characterization ◽  
Analytical Techniques ◽  
X Ray Diffraction ◽  
Depth Of Penetration ◽  
X Ray ◽  
The Past ◽  
Transmission Electron ◽  
Scanning Electron

Studies of the nature of a surface, either metallic or nonmetallic, in the past, have been limited to the instrumentation available for these measurements. In the past, optical microscopy, replica transmission electron microscopy, electron or X-ray diffraction and optical or X-ray spectroscopy have provided the means of surface characterization. Actually, some of these techniques are not purely surface; the depth of penetration may be a few thousands of an inch. Within the last five years, instrumentation has been made available which now makes it practical for use to study the outer few 100A of layers and characterize it completely from a chemical, physical, and crystallographic standpoint. The scanning electron microscope (SEM) provides a means of viewing the surface of a material in situ to magnifications as high as 250,000X.

scholarly journals Preparation and Characterization of Epoxidised and Acrylated Styrene/Isoprene/Styrene (SIS) Triblock Block Copolymer Based Nanocomposites

2013 ◽  
Vol 28 ◽  
pp. 84-88 ◽  
Author(s):  
Santosh Khanal ◽  
Alina Shakya ◽  
Goerg H. Michler ◽  
Boulos Youssef ◽  
Jean M. Saiter ◽  
...  
Keyword(s):  
Block Copolymer ◽  
Chemical Society ◽  
Performic Acid ◽  
Casting Method ◽  
Immiscible Polymers ◽  
Transmission Electron ◽  
Boehmite Nanoparticles ◽  
Solution Casting Method

In this work, a commercially available Styrene-Isoprene-Styrene (SIS)triblock copolymer was modified into epoxidised version (ESIS)using performic acid generated in situ from hydrogen peroxide and formic acid. The epoxidised sample was further acrylated to prepare acrylated version (ASIS). The nanocomposites of each sample (SIS, ESIS and ASIS) were prepared using boehmite nanoparticles as filler by solution casting method. The polymers were characterized by Fourier Transform Infrared (FTIR) spectroscopy and transmission electron microscopy (TEM). TEM investigations revealed that that the epoxidation of the diene block enhanced the dispersion of the nanofiller in the polymer matrix while the segregation of the nanoparticles towards the interface of the immiscible polymers was observed in the acrylated block copolymer based nanocomposite. DOI: http://dx.doi.org/10.3126/jncs.v28i0.8112 Journal of Nepal Chemical Society Vol. 28, 2011 Page: 84-88 Uploaded Date: May 24, 2013

scholarly journals ASDToolkit: A Novel MATLAB Processing Toolbox for ASD Field Spectroscopy Data

2020 ◽  
Author(s):  
Kathryn Elmer ◽  
Raymond Soffer ◽  
J. Pablo Arroyo-Mora ◽  
Margaret Kalacska
Keyword(s):  
Individual Characteristics ◽  
Atmospheric Conditions ◽  
Current Effort ◽  
Data Product ◽  
Field Spectroscopy ◽  
The Individual ◽  
Solar Position ◽  
Derived Data

Over the past 30 years, the use of field spectroscopy has risen in importance in remote sensing studies for the characterization of the surface reflectance of materials in situ within a broad range of applications. Potential uses range from measurements of individual targets of interest (e.g. vegetation, soils, validation targets etc.), to characterizing the contributions of different materials within larger spatially-mixed areas as would be representative of the spatial resolution captured by a sensor pixel (UAV to satellite scale). As such, it is essential that a complete and rigorous assessment of both the data-acquisition procedures, and the suitability of the derived data product be carried out. The measured energy from solar-reflected range spectroradiometers is influenced by the viewing and illumination geometries and the illumination conditions which vary due to changes in solar position and atmospheric conditions. By applying corrections, the estimated absolute reflectance (Rabs) of targets can be calculated. This property is independent of illumination intensity or conditions and is the metric commonly suggested to be used to compare spectra even when data are collected by different sensors or acquired under different conditions. By standardizing the process of estimated Rabs, as is provided in the described toolkit, consistency and repeatability in processing are ensured and the otherwise labor intensive and error-prone processing steps are streamlined. The resultant end data product (Rabs) represents our best current effort to generate consistent and comparable ground spectra which have been corrected for viewing and illumination geometries as well as other factors such as the individual characteristics of the reference panel used during acquisition.

Fabrication and In Situ Transmission Electron Microscope Characterization of Free-Standing Graphene Nanoribbon Devices

ACS Nano ◽  
2016 ◽  
Vol 10 (1) ◽  
pp. 1475-1480 ◽  
Author(s):  
Qing Wang ◽  
Ryo Kitaura ◽  
Shoji Suzuki ◽  
Yuhei Miyauchi ◽  
Kazunari Matsuda ◽  
...  
Keyword(s):  
Electron Microscope ◽  
Transmission Electron Microscope ◽  
Graphene Nanoribbon ◽  
Free Standing ◽  
Transmission Electron

scholarly journals Hydrogenative Cyclization of Levulinic Acid to γ-Valerolactone with Methanol and Ni-Fe Bimetallic Catalysts

Catalysts ◽  
2020 ◽  
Vol 10 (9) ◽  
pp. 1096
Author(s):  
Ligang Luo ◽  
Xiao Han ◽  
Qin Zeng
Keyword(s):  
Photoelectron Spectroscopy ◽  
Levulinic Acid ◽  
Hydrogen Donor ◽  
Effect Of Temperature ◽  
X Ray ◽  
Transmission Electron ◽  
Ft Ir ◽  
Temperature Programmed

A series of Ni-Fe/SBA-15 catalysts was prepared and tested for the catalytic hydrogenation of levulinic acid to γ-valerolactone, adopting methanol as the only hydrogen donor, and investigating the synergism between Fe and Ni, both supported on SBA-15, towards this reaction. The characterization of the synthesized catalysts was carried out by XRD (X-ray powder diffraction), TEM (transmission electron microscopy), H2-TPD (hydrogen temperature-programmed desorption), XPS (X-ray photoelectron spectroscopy), and in situ FT-IR (Fourier transform–infrared spectroscopy) techniques. H2-TPD and XPS results have shown that electron transfer occurs from Fe to Ni, which is helpful both for the activation of the C=O bond and for the dissociative activation of H2 molecules, also in agreement with the results of the in situ FT-IR spectroscopy. The effect of temperature and reaction time on γ-valerolactone production was also investigated, identifying the best reaction conditions at 200 °C and 180 min, allowing for the complete conversion of levulinic acid and the complete selectivity to γ-valerolactone. Moreover, methanol was identified as an efficient hydrogen donor, if used in combination with the Ni-Fe/SBA-15 catalyst. The obtained results are promising, especially if compared with those obtained with the traditional and more expensive molecular hydrogen and noble-based catalysts.

Growth and Characterization of Cobalt-filled Carbon Nanotubes Prepared by a Simple Catalytic Method

2003 ◽  
Vol 776 ◽  
Author(s):  
Xicheng Ma ◽  
Yuanhua Cai ◽  
Xia Li ◽  
Ning Lun ◽  
Shulin Wen
Keyword(s):  
Carbon Nanotubes ◽  
Metallic Nanoparticles ◽  
Low Cost ◽  
Catalytic Method ◽  
Selected Area Electron Diffraction ◽  
Transmission Electron ◽  
High Resolution Tem ◽  
One Step

AbstractHigh-quality cobalt-filled carbon nanotubes (CNTs) were prepared in situ in the decomposition of benzene over Co/silica-gel nano-scale catalysts. Unlike the previous reports, the catalysts needn't be pre-reduced prior to the forming of Co-filled CNTs, thus the advantage of this method is that Co-filled CNTs can be produced in one step, at a relatively low cost. Transmission electron microscopy (TEM) investigation showed that the products contained abundance of CNTs and most of them were filled with metallic nanoparticles or nanorods. High-resolution TEM (HRTEM), selected area electron diffraction (SAED) patterns and energy dispersive X-ray spectroscopy (EDS) confirmed the presence of Co inside the nanotubes. The encapsulated Co was further identified always as high temperature alpha-Co phase with fcc structure, which frequently consists of twinned boundaries and stacking faults. Based on the experimental results, a possible growth mechanism of the Co-filled CNTs was proposed.

In situ characterization of kinetics and mass transport of PbSe nanowire growth via LS and VLS mechanisms

Nanoscale ◽  
2019 ◽  
Vol 11 (13) ◽  
pp. 5874-5878 ◽  
Author(s):  
Miao Song ◽  
Jaewon Lee ◽  
Bin Wang ◽  
Benjamin A. Legg ◽  
Shenyang Hu ◽  
...  
Keyword(s):  
Mass Transport ◽  
Nucleation And Growth ◽  
In Situ Characterization ◽  
Transport Pathways ◽  
Structure Control ◽  
Transmission Electron ◽  
Gas Heating ◽  
Dependent Mass

We grew binary PbSe nanowires in an in situ gas-heating cell in a transmission electron microscope and elucidated species dependent mass transport pathways and correlations among supersaturation, nucleation, and growth kinetics, enabling structure control.

Correlative Nanomechanical Measurements for Complex Engineered Systems

MRS Advances ◽  
2016 ◽  
Vol 1 (12) ◽  
pp. 799-804 ◽  
Author(s):  
Eric D. Hintsala ◽  
Syed Asif ◽  
Douglas D. Stauffer
Keyword(s):  
Contact Pressure ◽  
Ex Situ ◽  
Metallic Oxide ◽  
Complex Engineered Systems ◽  
Transmission Electron ◽  
Important Input ◽  
Engineered Systems ◽  
The Individual ◽  
Disc Drive

ABSTRACTMultilayered film stacks, with length scales less than 10 nm are commonly used in a variety of devices, but present significant challenges to mechanical testing and evaluation. This is due to property convolution of the different layers. Both the properties of the individual layers and the combined response of the film stack are important input for design optimization. Here, we present ex-situ nanoindentation of a film stack representative of a perpendicular magnetic recording (PMR) hard disc drive (HDD), with more than 10 layers. We then compare this with in-situ transmission electron microscopy indentation to visualize deformation of individual layers of the stack. The ex-situ testing reveals early plastic deformation, with an initially high contact pressure (13 GPa) and modulus ( >160 GPa), followed by significant softening (8 GPa contact pressure and 140 GPa modulus), then slight hardening to 9 GPa. From in-situ testing, it is revealed that the metallic layer directly under the diamond like carbon (DLC) contributes the majority of the deformation and plastic flow, which is in turn constrained by a metallic oxide.

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