scholarly journals Perfection of unused Ni-Ti endodontic files, myth or reality? A scanning electron microscope (SEM) study

2015 ◽  
Vol 7 (2) ◽  
pp. 16-21 ◽  
Author(s):  
AbuMostafa Ammar ◽  
AlOmari Mohammed ◽  
AlQashtini Ihsan ◽  
AlAbdullah Nuha AlJabr Sara ◽  
Domia Reham
Keyword(s):  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
Sem Study ◽  
Scanning Electron

Neogene occurrences of the marine acritarch genusNannobarbophoraHabib and Knapp, 1982 emend., and the new speciesN. Gedlii

2003 ◽  
Vol 77 (2) ◽  
pp. 382-385 ◽  
Author(s):  
Martin J. Head
Keyword(s):  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
North Atlantic ◽  
Diagnostic Feature ◽  
Sem Study ◽  
Scanning Electron

The stratigraphic utility of small marine acritarchs in the Neogene has been known for more than a decade (e.g., de Vernal and Mudie, 1989). Their potential for biostratigraphy in the Cretaceous is also well known, and was elegantly elucidated by Habib and Knapp (1982) in a detailed scanning electron microscope (SEM) study from the western North Atlantic. Habib and Knapp erected 12 new acritarch genera including the acanthomorph genusNannobarbophoraand its three speciesN. barbata(the name of the type),N. pistilla, andN. platforma. A diagnostic feature ofNannobarbophorais the presence of spinules concentrated on, or restricted to, the surface of distally closed processes. Excystment is by a simple linear split (Habib and Knapp, 1982, p. 347).

Scanning Electron Microscopic Study of the Eggs of the Warthog Louse (Haematopinus Phacochoeri)

1997 ◽  
Vol 3 (S2) ◽  
pp. 113-114
Author(s):  
C. Baker ◽  
E.D. Green
Keyword(s):  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
Environmental Changes ◽  
General Structure ◽  
Electron Microscopic ◽  
Razor Blade ◽  
Scanning Electron Microscopic Study ◽  
Sem Study ◽  
Scanning Electron Microscopic ◽  
Scanning Electron

The large eggs of Haematopinus phacochoeri are found attached to the long dorsal mane bristles of the diurnal warthog. The eggs are generally exposed to great environmental stresses such as excessive sunlight and temperature as well as the occasional plunge under water or mud during grooming. This investigation was therefore undertaken to determine how the eggs of H. phococoeri are adapted to tolerate the various environmental changes it is constantly exposed to. To our knowledge no other SEM study on the eggs of this species has been performed.Specimens still attached to the bristles were fixed in 70% ethanol, dehydrated and ultrasonically cleaned. Some eggs were longitudinally sectioned with a razor blade to expose the chorionic layers. The eggs were critical point dried in liquid CO2, mounted and viewed by means of a Leica Stereoscan 420 scanning electron microscope.The general structure of the shell consists of two layers of chorion, i.e. the endo-and exochorion. These two layers are attached at the pre-formed line of weakness at the operculum and again near the hydropyle. Elsewhere these two layers are completely separated by the respiratory layer.

scholarly journals Early Cretaceous striate tricolpate pollen from the Borehole Mersa Matruh 1, North West Desert, Egypt

1988 ◽  
Vol 7 (2) ◽  
pp. 201-215 ◽  
Author(s):  
James H. J. Penny
Keyword(s):  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
New Taxa ◽  
Early Cretaceous ◽  
North West ◽  
Sem Study ◽  
Stratigraphic Ranges ◽  
Scanning Electron

Abstract. Striate tricolpate pollen has been recovered from Early Cretaceous samples of the borehole Mersa Matruh 1 in the N.W. Desert of Egypt. Scanning Electron Microscope (SEM) study has revealed fine details of their exine scupture, on the basis of which four new taxa, STRIOTRI-OVAL, STRIOTRI-SMOOTHMUR, STRIOTRI-SEGMUR and STRIORET-SMOOTH, are distinguished. The stratigraphic ranges of these are discussed and they are compared with other published species. They are among the oldest striate tricolpate pollen yet described, appearing in sediments of Early Aptian age, slightly predating the first reliable records of reticulate tricolpates in the sequence studied. The lack of earlier reticulate grains is attributed to possible sample failure. There is evidence that the true first appearance of tricoplate pollen in Egypt may be late Barrenian.

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.

SEM study on gastrulation; internal structure at the stage of ventral blastoporal groove in bufo arenarum

1978 ◽  
Vol 36 (2) ◽  
pp. 552-553
Author(s):  
Jorge Herkovits
Keyword(s):  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
Internal Structure ◽  
Sagittal Plane ◽  
Cell Types ◽  
Vitelline Membrane ◽  
Present Communication ◽  
Sem Study ◽  
Bufo Arenarum ◽  
Scanning Electron

SEM studies on amphibian gastrulation have shown the overall shape and arrangement of several cell types (e. g. bottle cells, mesodermal cells, ectodermal cells, etc. ) as well as the cellular activities in the blastocoel cavity during archenteron floor descent. The main purpose of the present communication is to show the internal structure of Bufo arenarum gastrula as viewed in sagittal dissection at the stage when the ventral blastoporal groove starts forming.Material and Methods: Bufo arenarum gastrula were fixed in 2, 5% glutaraldehyde in phosphate buffer for 2, 5 hrs. After removing the vitelline membrane the embryos were fractured and then dissected near the mid-sagittal plane. The specimens were dehydrated through an acetone series, dried according to the critical point technique, coated with evaporated gold-platinum and observed in a Jeol JSM-U3 scanning electron microscope operated at 5-15 kW.Observations: The internal structure of a Bufo arenarum gastrula at the ventral blastoporal groove stage is illustrated in Fig. 1. Blastocoel cavity (B), internal endodermal yolky cells (Y), prospective ectoderm (PE), archenteron (A), dorsal blastoporal lip (L), ventral blastoporal groove (V).

scholarly journals SEM study of crystal morphology in the Zn4(OH)6SO4·nH2O system (n = 1, 3, 4, 5)

2020 ◽  
Vol 81 (3) ◽  
pp. 31-33
Author(s):  
Stefka Dencheva ◽  
Tsveta Stanimirova ◽  
Georgi Kirov
Keyword(s):  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
Room Temperature ◽  
Crystal Morphology ◽  
High Rate ◽  
Microscopic Images ◽  
Sem Study ◽  
Dehydration Processes ◽  
First Time ◽  
Scanning Electron

For the first time, a change in the morphology of crystals associated with reversible dehydration processes was revealed and discussed. It was found that in the column of the scanning electron microscope the dehydration proceeds at a high rate and reaches the maximum possible degree that can be achieved at room temperature. The microscopic images show the shapes of the transformed monohydrate phase.

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