Comparative LM, SEM and EDAX study of chalk glands on leaf and stem of two species of Plumbago Linn.

Stem and leaves of two species of PlumbagoLinn.viz. P. zeylanica Linn.andP. auriculata Lam. were investigated for the structure and chemical composition of chalk glands. Light Microscopy (LM) and Scanning Electron Microscopy (SEM) revealed the presence of chalk glands on both lower as well as upper surface of leaf and stem of both species. Chalk glands are abundant on lower surface and sparse on upper surface of leaf. Chalk glands are approximately hemispherical glands with oval or almost circular outline. It is composed of 8 cells arranged in two circles – central circle of 4 secretory cells and outer circle of 4 adjoining cells. Each secretory cell has depression which corresponds to pore. Each gland is surrounded by 4 subsidiary cells. No significant difference in the structure of chalk glands in both species was noticed. Chalk glands occupy three different positions with regard to epidermal cells –at the same level of the epidermis, slightly sunken in the epidermis and slightly raised above the epidermis. Common elements found in EDAX analysis of all chalk glands are carbon, oxygen, magnesium, sulphur, potassium and calcium. Differences in the presence of elements silicon, chlorine, aluminium, sodium, phosphorus were observed. The presence of significant amount of calcium in chalk glands and their dried deposits and absence of sodium and chlorine from dried deposits and even in some chalk glands appealed to use the term ‘Chalk gland’ instead of ‘Salt gland’ in Plumbago.

A Scanning Electron Microscope Study of Isolated Guard Cells

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s042482010007271x ◽

1973 ◽

Vol 31 ◽

pp. 454-455 ◽

Cited By ~ 1

Author(s):

P. Dayanandan ◽

P. B. Kaufman

Keyword(s):

Electron Microscope ◽

Electron Microscope Study ◽

Three Dimensional ◽

Guard Cells ◽

Scanning Electron Microscope Study ◽

Psilotum Nudum ◽

Subsidiary Cells ◽

Welwitschia Mirabilis ◽

Cycas Revoluta ◽

A three dimensional appreciation of the guard cell morphology coupled with ultrastjuctural studies should lead to a better understanding of their still obscure dynamics of movement. We have found the SEM of great value not only in studies of the surface details of stomata but also in resolving the structures and relationships that exist between the guard and subsidiary cells. We now report the isolation and SEM studies of guard cells from nine genera of plants.Guard cells were isolated from the following plants: Psilotum nudum, four species of Equisetum, Cycas revoluta, Ceratozamia sp., Pinus sylvestris, Ephedra cochuma, Welwitschia mirabilis, Euphorbia tirucalli and Allium cepa.

Scanning Electron Microscopy Analysis of the Anterior Capsulotomy Edge: A Comparative Study between Femtosecond Laser-Assisted Capsulotomy and Manual Capsulorhexis

Journal of Ophthalmology ◽

10.1155/2018/8620150 ◽

2018 ◽

Vol 2018 ◽

pp. 1-6 ◽

Cited By ~ 2

Author(s):

Daniele Tognetto ◽

Chiara De Giacinto ◽

Alberto Armando Perrotta ◽

Tommaso Candian ◽

Alessandro Bova ◽

...

Keyword(s):

Electron Microscopy ◽

Femtosecond Laser ◽

Comparative Study ◽

Surface Irregularity ◽

Significant Difference ◽

Group 2 ◽

Cut Surface ◽

Scanning Electron ◽

Group 1

Purpose. To compare the capsule edges ultrastructure obtained by two femtosecond laser-assisted cataract surgery (FLACS) platforms and manual continuous curvilinear capsulorhexis (CCC) using scanning electron microscopy (SEM). Setting. Eye Clinic, University of Trieste, Italy. Design. Experimental comparative study. Methods. 150 anterior capsules were collected and divided into three groups as follows: Group 1 (50 capsules) obtained with manual CCC, Groups 2 and 3 (each with 50 capsules) obtained with the Catalys Laser and the LenSx Laser, respectively. All samples were imaged by means of SEM and regularity of the cut surface, and thickness of the capsule edge were evaluated and compared. Results. All femtosecond laser (FSL) capsules were perfectly circular, whereas some alteration of the circular shape was observed in the manual ones. Group 1 showed a smooth and regular capsule edge without any surface irregularity, conversely Groups 2 and 3 showed postage-stamp perforations on the capsule edge. The cut surface irregularity value in Group 2 was 1.4 ± 0.63, while it was 0.7 ± 0.49 in Group 3 (p<0.05). Group 1 had a significantly lower thickness of the capsule edge than the FSL groups (p<0.05). No statistically significant difference in the capsule edge thickness between the FSL groups was found (p=0.244). Conclusions. Despite the presence of slight cut surface irregularities, both FSL capsulotomies showed a better geometry and circularity than the manual ones. Capsulotomy specimens obtained using both FSL capsulotomies showed laser-induced alterations of the capsule edge when compared with smooth and regular edges obtained using manual CCC.

Effects of Long Durations of RF–Magnetron Sputtering Deposition of Hydroxyapatite on Titanium Dental Implants

European Journal of Dentistry ◽

10.1055/s-0040-1721314 ◽

2021 ◽

Author(s):

Ihab Nabeel Safi ◽

Basima Mohammed Ali Hussein ◽

Hikmat J. Aljudy ◽

Mustafa S. Tukmachi

Keyword(s):

Electron Microscopy ◽

Magnetron Sputtering ◽

Dental Implants ◽

Substrate Surface ◽

Rf Magnetron Sputtering ◽

P Value ◽

Edx Analysis ◽

Significant Difference ◽

Abstract Objectives Dental implant is a revolution in dentistry; some shortages are still a focus of research. This study use long duration of radiofrequency (RF)–magnetron sputtering to coat titanium (Ti) implant with hydroxyapatite (HA) to obtain a uniform, strongly adhered in a few micrometers in thickness. Materials and Methods Two types of substrates: discs and root form cylinders were prepared using a grade 1 commercially pure (CP) Ti rod. A RF–magnetron sputtering device was used to coat specimens with HA. Magnetron sputtering was set at 150 W for 22 hours at 100°C under continuous argon gas flow and substrate rotation at 10 rpm. Coat properties were evaluated via field emission scanning electron microscopy (FESEM), scanning electron microscopy–energy dispersive X-ray (EDX) analysis, atomic force microscopy, and Vickers hardness (VH). Student’s t-test was used. Results All FESEM images showed a homogeneous, continuous, and crack-free HA coat with a rough surface. EDX analysis revealed inclusion of HA particles within the substrate surface in a calcium (Ca)/phosphorus (P) ratio (16.58/11.31) close to that of HA. Elemental and EDX analyses showed Ca, Ti, P, and oxygen within Ti. The FESEM views at a cross-section of the substrate showed an average of 7 µm coat thickness. Moreover, these images revealed a dense, compact, and uniform continuous adhesion between the coat layer and the substrate. Roughness result indicated highly significant difference between uncoated Ti and HA coat (p-value < 0.05). A significant improvement in the VH value was observed when coat hardness was compared with the Ti substrate hardness (p-value < 0.05). Conclusion Prolonged magnetron sputtering successfully coat Ti dental implants with HA in micrometers thickness which is well adhered essentially in excellent osseointegration.

Bonding and Thermal Cycling Performances of Two (Poly)Aryl–Ether–Ketone (PAEKs) Materials to an Acrylic Denture Base Resin

Polymers ◽

10.3390/polym13040543 ◽

2021 ◽

Vol 13 (4) ◽

pp. 543 ◽

Cited By ~ 1

Author(s):

Tzu-Yu Peng ◽

Saiji Shimoe ◽

Lih-Jyh Fuh ◽

Chung-Kwei Lin ◽

Dan-Jae Lin ◽

...

Keyword(s):

Surface Roughness ◽

Thermal Cycling ◽

Fatigue Testing ◽

Lower Surface ◽

Aryl Ether ◽

Bonding Performance ◽

Significant Difference ◽

Aryl Ether Ketone ◽

Ether Ketone ◽

Thermal Cycling Fatigue

Poly(aryl–ether–ketone) materials (PAEKs) are gaining interest in everyday dental practices because of their natural properties. This study aims to analyze the bonding performance of PAEKs to a denture acrylic. Testing materials were pretreated by grinding, sandblasting, and priming prior to polymerization with the denture acrylic. The surface morphologies were observed using a scanning electron microscope and the surface roughness was measured using atomic force microscopy. The shear bond strength (SBS) values were determined after 0 and 2500 thermal cycles. The obtained data were analyzed using a paired samples t-test and Tukey’s honestly significant difference (HSD) test (α = 0.05). The surface characteristics of testing materials after different surface pretreatments showed obvious differences. PAEKs showed lower surface roughness values (0.02–0.03 MPa) than Co-Cr (0.16 MPa) and zirconia (0.22 MPa) after priming and sandblasting treatments (p < 0.05). The SBS values of PAEKs (7.60–8.38 MPa) met the clinical requirements suggested by ISO 10477 (5 MPa). Moreover, PAEKs showed significantly lower SBS reductions (p < 0.05) after thermal cycling fatigue testing compared to Co-Cr and zirconia. Bonding performance is essential for denture materials, and our results demonstrated that PAEKs possess good resistance to thermal cycling fatigue, which is an advantage in clinical applications. The results imply that PAEKs are potential alternative materials for the removable of prosthetic frameworks.

Biogenesis of Plasma Membranes in Salt Glands of Salt-Stressed Domestic Ducklings: Localization of Acyltransferase Activity

Journal of Cell Science ◽

10.1242/jcs.11.3.855 ◽

1972 ◽

Vol 11 (3) ◽

pp. 855-873

Author(s):

A. M. LEVINE ◽

JOAN A. HIGGINS ◽

R. J. BARRNETT

Keyword(s):

Plasma Membrane ◽

Plasma Membranes ◽

Specific Activity ◽

Salt Gland ◽

Secretory Cells ◽

Salt Glands ◽

Acyltransferase Activity ◽

Structural Localization ◽

Differentiated Cells ◽

Golgi Membranes

In response to salt water stress there is a marked increase in the plasma membranes of the epithelial secretory cells of the salt glands of domestic ducklings. In the present study, the fine-structural localization of the acyltransferases involved in synthesis of phospholipids has been investigated in this tissue during this increased biogenesis of plasma membranes. The specific activity of the acyltransferases of the salt gland rose in response to salt stress, and this preceded the rapid increase in weight and cellular differentiation. After the weight increase of the gland became established, the specific activity of the acyltransferases declined, but the total activity remained constant. Salt gland tissue fixed in a mixture of glutaraldehyde and formaldehyde retained 35% of the acyltransferase activity of unfixed tissue. Cytochemical studies of the localization of acyltransferase activity in fixed and unfixed salt gland showed reaction product associated only with the lamellar membranes of the Golgi complex. This localization occurred in partially differentiated cells from salt-stressed glands to the greatest extent; and to only a small extent in cells of control tissue from unstressed salt glands. Omission of substrates resulted in absence of reaction product in association with the Golgi membranes. In addition, vesicles having limiting membranes morphologically similar to the plasma membrane occurred between the Golgi region and the plasma membrane in the partially differentiated cells. The phospholipid component of the plasma membrane appears therefore to be synthesized in association with the Golgi membranes and the membrane packaged at this site from which it moves in the form of vesicles to fuse with the pre-existing plasma membrane.

Characterization of Chitosan Obtained from Snail Shell (Achatina fulica) and its Excipient Potentials in Metronidazole Tablet Formulation

Dhaka University Journal of Pharmaceutical Sciences ◽

10.3329/dujps.v19i2.50855 ◽

2021 ◽

Vol 20 (1) ◽

pp. 31-39

Author(s):

Oluyemisi Adebowale Bamiro ◽

Aishat Oyinkansola Salisu ◽

Ese Mary Iyere ◽

Olatundun Atoyegbe ◽

Olutayo Ademola Adeleye ◽

...

Keyword(s):

Tablet Formulation ◽

Achatina Fulica ◽

Flow Properties ◽

Crushing Strength ◽

Snail Shell ◽

Significant Difference ◽

Swelling Capacity ◽

Tablet Formulations ◽

The aim of the work was to characterize chitosan extracted from snail shell and evaluate its use as a disintegrant and binder in metronidazole tablet formulation in comparison with standard chitosan (SC). The mechanical properties were assessed using crushing strength and friability, while the release properties were assessed using disintegration and dissolution times. The extracted chitosan (EC) was crystalline in nature and the scanning electron microscopy (SEM) showed polygonal particles with rough surface. The moisture and swelling capacity was 1.80% and 15.00%, respectively. The densities and flow properties were significantly (p<0.05) higher than those of the SC. As a binder, the crushing strength of formulations containing EC was higher than SC, but both formulation failed friability test. There was significant difference between the disintegration times of the metronidazole formulations containing EC and SC as a disintegrant. The result showed that EC is more effective as a binder in tablet formulations. Dhaka Univ. J. Pharm. Sci. 20(1): 31-39, 2021 (June)

Microleakage Evaluation of Composite Restorations Following Papain-Based Chemo-Mechanical Caries Removal in Primary Teeth

Journal of Clinical Pediatric Dentistry ◽

10.17796/1053-4628-41.1.53 ◽

2017 ◽

Vol 41 (1) ◽

pp. 53-61 ◽

Cited By ~ 3

Author(s):

Marwa Abdel Hafez ◽

Mona Elkateb ◽

Sonia El Shabrawy ◽

Amel Mahmoud ◽

Omar El Meligy

Keyword(s):

Electron Microscopy ◽

Microscopy Study ◽

Hybrid Layer ◽

Composite Restorations ◽

Nail Polish ◽

Significant Difference ◽

Drilling Method ◽

Caries Removal ◽

Aim: To evaluate the microleakage of composite restorations following Papain-based chemo-mechanical caries removal compared to the conventional drilling method. The characteristic of the hybrid layer was also studied using scanning electron microscopy. Study design: The sample included thirty freshly extracted and exfoliated primary molars with open proximal carious dentin lesions. Teeth were divided into two equal groups, according to method of caries removal. Following caries removal, cavity preparations were restored with composite resin. After thermocycling, teeth were sealed apically and coated with nail polish except the surface of restorations and the surrounding 1mm. Teeth were immersed in basic fuschin dye solution, then they were sectioned mesiodistally. The extent of dye penetration was detected using a light stereomicroscope. After microleakage test, the resin/dentin interface was examined using scanning electron microscopy. Results: There was no significant difference in the degree of leakage between both groups. In the Papacarie group, longer and numerous resin tags were observed with statistically significant thicker hybrid layer than those following the drilling method. However, there was no significant difference between the diameters of resin tags of both groups. Conclusions: Papacarie does not adversely affect the microleakage of composite restorations and provides a suitable surface for bonding.

Bracket base remnants after orthodontic debonding

The Angle Orthodontist ◽

10.2319/121112-930.1 ◽

2013 ◽

Vol 83 (5) ◽

pp. 885-891 ◽

Cited By ~ 7

Author(s):

Matteo Zanarini ◽

Antonio Gracco ◽

Monica Lattuca ◽

Silvia Marchionni ◽

Maria Rosaria Gatto ◽

...

Keyword(s):

Energy Dispersive ◽

Scanning Electron Micrographs ◽

X Ray ◽

Significant Difference ◽

Group A ◽

Fixed Appliances ◽

Group B ◽

Imagej Software ◽

Bracket Base ◽

ABSTRACT Objective: To evaluate whether the debonding procedure leads to restitutio ad integrum of the enamel surface by investigating the presence of enamel within the bracket base remnants after debonding. Materials and Methods: Sixty patients who completed orthodontic treatment with fixed appliances were included. A total of 1068 brackets were microphotographed; the brackets presenting some remnants on the base (n = 818) were selected and analyzed with ImageJ software to measure the remnant area. From this population a statistically significant sample (n = 100) was observed under a scanning electron microscope to check for the presence of enamel within the remnants. Energy dispersive x-ray spectrometry was also performed to obtain quantitative data. Results: Statistically significant differences in the remnant percentage between arches were observed for incisor and canine brackets (P < .0001 and P = .022, respectively). From a morphologic analysis of the scanning electron micrographs the bracket bases were categorized in 3 groups: group A, bases presenting a thin enamel coat (83%); group B, bases showing sizable enamel fragments (7%); group C, bases with no morphologic evidence of enamel presence (10%). Calcium presence was noted on all evaluated brackets under energy dispersive x-ray spectrometry. No significant difference was observed in the Ca/Si ratio between group A (16.21%) and group B (18.77%), whereas the Ca/Si ratio in group C (5.40%) was significantly lower than that of the other groups (P < .323 and P = .0001, respectively). Conclusion: The objective of an atraumatic debonding is not achieved yet; in some cases the damage could be clinically relevant.

Prosthetic laboratory influence on the vertical misfit at the implant/UCLA abutment interface

Brazilian Dental Journal ◽

10.1590/s0103-64402007000200010 ◽

2007 ◽

Vol 18 (2) ◽

pp. 139-143 ◽

Cited By ~ 21

Author(s):

Gustavo Augusto Seabra Barbosa ◽

Paulo Cézar Simamoto Júnior ◽

Alfredo Júlio Fernandes Neto ◽

Maria da Glória Chiarello de Mattos ◽

Flávio Domingues das Neves

Keyword(s):

Electron Microscopy ◽

Casting Process ◽

Significant Difference ◽

An inadequate fit at the abutment/implant interface can generate mechanical and biological problems. The laboratorial stages could induce misfit in such interface when the castable UCLA abutment type is used. The purpose of this study was to comparatively evaluate the performance of three prosthetic laboratories (Labs A, B and C) by vertical fit analysis of castable UCLA abutments on the casting and soldering stages of the same prosthesis. Four fixed prostheses were built by each laboratory using castable UCLA abutments. The evaluation was made by scanning electron microscopy under 500x magnification in the mesial and distal regions of each element of the prosthesis, totalizing 24 measurements per laboratory. The results were analyzed statistically by Kruskal-Wallis test (p<0.05). In the casting process, the values presented by the laboratories differed significantly to each other (p=0.004). After soldering, the values presented by the laboratories showed no significant difference (p=0.948). It may be concluded that the fit values obtained in the casting stage of UCLA abutments can be influenced when processed by different laboratories, and that conventional soldering itself increased the degree of framework misfit, regardless of which laboratory made it.

Problems associated with ageing squid from their statoliths: towards a more structured approach

Antarctic Science ◽

10.1017/s0954102094000337 ◽

1994 ◽

Vol 6 (2) ◽

pp. 215-222 ◽

Cited By ~ 25

Author(s):

Marek R. Lipinski ◽

M. Deon Durholtz

Keyword(s):

Electron Microscopy ◽

Regression Analysis ◽

Light Microscopy ◽

The Other ◽

Etching Solution ◽

Significant Difference ◽

Structured Approach ◽

Fish Otoliths ◽

It appears that squid statoliths cannot yet be regarded as accurate an ageing tool as fish otoliths. Statoliths from the same pair, prepared differently for viewing and counting increments, were compared. Increment counts do not imply age in days, because this was not validated. One statolith from each pair was examined by light microscopy (LM) after preparation following a new method. The other was viewed by Scanning Electron microscopy (SEM) with a modified etching solution. Shape of each statolith was similar when compared by multiple regression analysis (11 variables, n=53). There was a weak but significant difference between sexes (statoliths of females were slightly larger). All other differences were insignificant. Microscopic observation and increment counts of increments were successfully carried out for 37 pairs of statoliths. Significant differences between two independent counts were found for the LM method, but no significant differences were found between two independent SEM counts. Counts were significantly different when interpreted by both LM and SEM, probably because of poor resolution in the LM readings and over-resolution (growth layers prominent and numerous) in those read by SEM. Recommendations are made on how ageing studies, based on statoliths, should be structured and the results evaluated.