Platelet activation in rabbits with decompression sickness

2020 ◽  
pp. 597-605
Author(s):  
Phuc Hong Cao ◽  
Bao Quoc Dang ◽  
Thu Van Nguyen ◽  
Linh Tung Nguyen ◽  
Keyword(s):  
Platelet Count ◽  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
Platelet Activation ◽  
Decompression Sickness ◽  
Peripheral Blood Cell ◽  
Group A ◽  
Platelet Microparticles ◽  
Scanning Electron ◽  
Platelet Shape

Platelets are the most easily altered type of peripheral blood cell in decompression sickness (DCS), which can feature decreased platelet count and the appearance of platelet microparticles in plasma. We hypothesized that DCS results in platelet activation in the bloodstream. The present study was carried out on 45 rabbits. The platelet count and concentration of plasma platelet markers were determined in 35 rabbits; the platelet shape was observed under scanning electron microscope in 10 rabbits. All indexes were collected at two points: 24 hours before the simulated dive and 30 minutes after the simulated dive. Platelet count decreased noticeably after DCS, from 380.10 ± 73.61 (G/L) to 330.23 ± 115.72 (G/L), a change of approximately -13.49 ± 25.57 (%). Platelet count was further decreased in the severe DCS group (a change of -45.99 ± 18.57%). Platelet count after DCS was proportional to the survival time of the rabbits after DCS. The concentration of two plasma platelet markers (PF4 and BTG) did not demonstrate statistically significant change at 30 minutes after DCS. However, platelet shape was changed, and the following features were observed: oblong, distortion, flattening shape, sticking together, mixing of membrane, and abundance of pseudopods with a 100- to 200-nm diameter. We conclude there is platelet activation in the bloodstream in cases of DCS.

Influence of prophylaxis on the microleakage of sealants: in vitro study

2002 ◽  
Vol 26 (4) ◽  
pp. 371-375 ◽  
Author(s):  
Ana Beatriz Alonso Chevitarese ◽  
Orlando Chevitarese ◽  
Ivete Pomarico Ribeiro de Souza ◽  
Roberto Braga de Carvalho Vianna
Keyword(s):  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
In Vitro Study ◽  
Optical Microscope ◽  
Vitro Study ◽  
Significant Difference ◽  
Group A ◽  
Group B ◽  
Scanning Electron

The aim of this study was to evaluate the influence of prophylaxis on the sealants microleakage in 30 premolars divided into: Group A, Group B and Group C. The teeth were analyzed using the optical microscope (OM) and at scanning electron microscope (SEM). There was a statitical significant difference among the groups regarding the presence of microleakage, but not with the presence of tags.

scholarly journals Revised Morphological Characteristics of Species of Two Ostracod Genera Loxoconcha Sars, 1866 (Loxoconchidae) and Xestoleberis Sars, 1866 (Xestoleberididae)

2021 ◽  
Author(s):  
Doan Dung Le
Keyword(s):  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
Morphological Characteristics ◽  
Phylogenetic Groups ◽  
Group A ◽  
Vertical Row ◽  
Fossil Records ◽  
Oval Shape ◽  
Scanning Electron

Abstract Total 23 species of the genus Loxoconcha and 21 species of the genus Xestoleberis were presented in this study. A scanning electron microscope for observing muscle scars of the carapaces, and a stereoscopic microscope for dissecting, observing and sketching the appendages were used. The results show that most species of the genus Loxoconcha consist of four adductor scars to arrange in a curved sub-vertical row and concave anteriorly, except L. pulchra carrying five, in which the top one is divided into two. The frontal scars with C-shape, opening anteriorly are presented in most of Loxoconcha species, however, the frontal scar with bean-shape or oval-shape is discovered in five species of L. japonica group. Most of L. kosugii bear the frontal scar with C-shape, but the frontal scar with Y-shape is found in several individuals. This phenemenon shows the close phylogeny between the genus Loxoconcha and Palmoconcha. About the genus Xestoleberis, chaetotaxy of setae on all appendages, except setae of exopodite on the maxillula is a typical character of this genus. The published fossil records and the tendencies of change in the number of setae on the maxillula and mandible among three phylogenetic groups suggest that Group A or B is an ancestor of the genus Xestoleberis, and Group C is a derived group.

scholarly journals Characteristics of Particles and Debris Released after Implantoplasty: A Comparative Study

Materials ◽  
2022 ◽  
Vol 15 (2) ◽  
pp. 602
Author(s):  
Xixi Wu ◽  
Changjie Cai ◽  
Javier Gil ◽  
Elizabeth Jantz ◽  
Yacoub Al Sakka ◽  
...  
Keyword(s):  
Electron Microscope ◽  
Chemical Composition ◽  
Scanning Electron Microscope ◽  
Surface Area ◽  
Particle Number ◽  
Significant Difference ◽  
Group A ◽  
Particle Sizer ◽  
Group B ◽  
Scanning Electron

Titanium particles embedded on peri-implant tissues are associated with a variety of detrimental effects. Given that the characteristics of these detached fragments (size, concentration, etc.) dictate the potential cytotoxicity and biological repercussions exerted, it is of paramount importance to investigate the properties of these debris. This study compares the characteristics of particles released among different implant systems (Group A: Straumann, Group B: BioHorizons and Group C: Zimmer) during implantoplasty. A novel experimental system was utilized for measuring and collecting particles generated from implantoplasty. A scanning mobility particle sizer, aerodynamic particle sizer, nano micro-orifice uniform deposit impactor, and scanning electron microscope were used to collect and analyze the particles by size. The chemical composition of the particles was analyzed by highly sensitive microanalysis, microstructures by scanning electron microscope and the mechanical properties by nanoindentation equipment. Particles released by implantoplasty showed bimodal size distributions, with the majority of particles in the ultrafine size range (<100 nm) for all groups. Statistical analysis indicated a significant difference among all implant systems in terms of the particle number size distribution (p < 0.0001), with the highest concentration in Group B and lowest in Group C, in both fine and ultrafine modes. Significant differences among all groups (p < 0.0001) were also observed for the other two metrics, with the highest concentration of particle mass and surface area in Group B and lowest in Group C, in both fine and ultrafine modes. For coarse particles (>1 µm), no significant difference was detected among groups in terms of particle number or mass, but a significantly smaller surface area was found in Group A as compared to Group B (p = 0.02) and Group C (p = 0.005). The 1 first minute of procedures had a higher number concentration compared to the second and third minutes. SEM-EDS analysis showed different morphologies for various implant systems. These results can be explained by the differences in the chemical composition and microstructures of the different dental implants. Group B is softer than Groups A and C due to the laser treatment in the neck producing an increase of the grain size. The hardest implants were those of Group C due to the cold-strained titanium alloy, and consequently they displayed lower release than Groups A and B. Implantoplasty was associated with debris particle release, with the majority of particles at nanometric dimensions. BioHorizons implants released more particles compared to Straumann and Zimmer. Due to the widespread use of implantoplasty, it is of key importance to understand the characteristics of the generated debris. This is the first study to detect, quantify and analyze the debris/particles released from dental implants during implantoplasty including the full range of particle sizes, including both micro- and nano-scales.

scholarly journals Scanning Electron Microscope Image Analysis of Bonding Surfaces following Removal of Composite Resin Restoration Using Er: YAG Laser: In Vitro Study

Scanning ◽  
2021 ◽  
Vol 2021 ◽  
pp. 1-7
Author(s):  
Dlsoz Omer Babarasul ◽  
Bestoon Mohammed Faraj ◽  
Fadil Abdullah Kareem
Keyword(s):  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
Pulse Repetition Rate ◽  
High Speed ◽  
Composite Resin ◽  
Yag Laser ◽  
Group A ◽  
Composite Resin Restoration ◽  
Group B ◽  
Scanning Electron

It is impossible to remove tooth-colored restorations by mechanical means without unnecessary damage to the adjacent sound tooth structure. This study is aimed at investigating erbium-doped yttrium aluminum garnet (Er: YAG) laser (Hoya ConBio, VersaWave, CA, USA) in removing composite resin restorations and assessing the change in morphology of bonding surfaces using a scanning electron microscope (EDX, CAMSCANNER, 3200LV, UK). The investigators collected thirty extracted sound human premolar teeth for this investigation, and the conventional design class V cavity was prepared on the buccal surface of each specimen. The specimens were allocated randomly into three groups, according to the procedure used for the ablation of the composite restoration: group A (high-speed diamond fissure bur), group B, and group C (Er: YAG laser) using a different pulse repetition rate of 20 Hz (group B) and 25 Hz (group C). The AutoCAD software program (Autodesk, Inc., 2016) was used to calculate the surface area and the resulting dimensional change of the cavities after restoration removal. The cavities were filled with composite resin and randomly assigned into two groups conforming to the methods applied to eliminate the restoration; diamond turbine fissure bur and laser. In each group, two specimens were selected randomly for scanning electron microscope analysis of bonding surfaces. The least meantime for the composite resin removal was observed in the high-speed diamond bur, significantly less than both Er-YAG laser groups ( p < 0.001 ). However, at a higher pulse repetition rate, time-consuming decreased. The results showed that laser is more conservative in removing composite resin restoration as the change was most remarkable in group A (0.800 mm), then group C (0.466 mm), and the slightest change is in group B (0.372 mm) ( p = 0.014 ). The dentin surface of group A showed a smooth surface with no opened dentinal tubule and intact smear layer. In groups B and C, dentin surfaces were irregular, scaly, or flaky, and dentinal tubules were opened without a smear layer. Therefore, Er: YAG laser is effective for composite resin removal considering the parameters chosen in this study with fewer changes in cavity surface area and better microretentive features.

scholarly journals Evaluation of Effectiveness of Cleaning of Root Canals using Protaper and K3 Rotary Systems: A SEM Study

2015 ◽  
Vol 6 (1) ◽  
pp. 20-25
Author(s):  
K Shashikala ◽  
BS Keshava Prasad ◽  
Anukriti Tyagi
Keyword(s):  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
Smear Layer ◽  
Root Canals ◽  
Significant Difference ◽  
Sem Study ◽  
Group A ◽  
Group B ◽  
Scanning Electron

ABSTRACT The aim of this in vitro study was to compare the debris and smear layer removal following root canal preparation using two different rotary systems with scanning electron microscope (SEM). The rotary systems used were Protaper and K3. Forty single rooted permanent mandibular premolars were chosen for the study. They were assigned two groups on the basis of instrumentation used. The teeth were sectioned at the level of cementoenamel junction and instrumented with Protaper in group A and with K3 in group B. The root canals were thoroughly irrigated with 5 ml of 2.5 % NaOCl during instrumentation. After instrumentation, 5 ml of normal saline was used as a final rinse. The teeth were split longitudinally and the specimens were prepared for SEM evaluation. Scanning electron microscope photomicrographs showed presence of debris and smear layer. The SEM photomicrographs were scored, based on the standard score rating system, and the scores were tabulated accordingly. The scores obtained from the specimens were subjected to statistical analysis. Results showed opening of dentinal tubules and effective removal of smear layer in group A (Protaper) and no significant difference between both the groups (groups A and B) regarding debris. How to cite this article Tyagi A, Prasad BSK, Shashikala K. Evaluation of Effectiveness of Cleaning of Root Canals using Protaper and K3 Rotary Systems: A Sem Study. World J Dent 2015;6(1):20-25.

The Alteration of the Pore Spaces in Sandstones

1973 ◽  
Vol 31 ◽  
pp. 210-211
Author(s):  
R. E. Ferrell ◽  
G. G. Paulson
Keyword(s):  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
The Other ◽  
Coarse Grained ◽  
Depositional Fabric ◽  
Soluble Components ◽  
Scanning Electron ◽  
Shape And Size

The pore spaces in sandstones are the result of the original depositional fabric and the degree of post-depositional alteration that the rock has experienced. The largest pore volumes are present in coarse-grained, well-sorted materials with high sphericity. The chief mechanisms which alter the shape and size of the pores are precipitation of cementing agents and the dissolution of soluble components. Each process may operate alone or in combination with the other, or there may be several generations of cementation and solution.The scanning electron microscope has ‘been used in this study to reveal the morphology of the pore spaces in a variety of moderate porosity, orthoquartzites.

The Broad Applications of the Scanning Electron Microscope

1969 ◽  
Vol 27 ◽  
pp. 20-21
Author(s):  
C. T. Nightingale ◽  
S. E. Summers ◽  
T. P. Turnbull
Keyword(s):  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
Light Microscopy ◽  
Surface Topography ◽  
Great Depth ◽  
Resolving Power ◽  
Depth Of Field ◽  
Pictorial Representations ◽  
Scanning Electron

The ease of operation of the scanning electron microscope has insured its wide application in medicine and industry. The micrographs are pictorial representations of surface topography obtained directly from the specimen. The need to replicate is eliminated. The great depth of field and the high resolving power provide far more information than light microscopy.

Observability of Very Thick Specimen by Using Transmission Scanning Electron Microscope

1971 ◽  
Vol 29 ◽  
pp. 26-27
Author(s):  
K. Shibatomi ◽  
T. Yamanoto ◽  
H. Koike
Keyword(s):  
Electron Microscope ◽  
Image Quality ◽  
Scanning Electron Microscope ◽  
Chromatic Aberration ◽  
Image Contrast ◽  
Objective Lens ◽  
Thick Specimen ◽  
Transmission Electron ◽  
Scanning Electron

In the observation of a thick specimen by means of a transmission electron microscope, the intensity of electrons passing through the objective lens aperture is greatly reduced. So that the image is almost invisible. In addition to this fact, it have been reported that a chromatic aberration causes the deterioration of the image contrast rather than that of the resolution. The scanning electron microscope is, however, capable of electrically amplifying the signal of the decreasing intensity, and also free from a chromatic aberration so that the deterioration of the image contrast due to the aberration can be prevented. The electrical improvement of the image quality can be carried out by using the fascionating features of the SEM, that is, the amplification of a weak in-put signal forming the image and the descriminating action of the heigh level signal of the background. This paper reports some of the experimental results about the thickness dependence of the observability and quality of the image in the case of the transmission SEM.

Resolution of a Transmitted Electron Image Formed by A Scanning Electron Microscope

1970 ◽  
Vol 28 ◽  
pp. 386-387
Author(s):  
S. Takashima ◽  
H. Hashimoto ◽  
S. Kimoto
Keyword(s):  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
Chromatic Aberration ◽  
Objective Lens ◽  
Specimen Thickness ◽  
Probe Diameter ◽  
Transmission Electron ◽  
Electron Image ◽  
Conventional Transmission Electron Microscope ◽  
Scanning Electron

The resolution of a conventional transmission electron microscope (TEM) deteriorates as the specimen thickness increases, because chromatic aberration of the objective lens is caused by the energy loss of electrons). In the case of a scanning electron microscope (SEM), chromatic aberration does not exist as the restrictive factor for the resolution of the transmitted electron image, for the SEM has no imageforming lens. It is not sure, however, that the equal resolution to the probe diameter can be obtained in the case of a thick specimen. To study the relation between the specimen thickness and the resolution of the trans-mitted electron image obtained by the SEM, the following experiment was carried out.

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