Viviparity and embryonic adaptations in the teleost Clinus superciliosus

1980 ◽  
Vol 58 (1) ◽  
pp. 1-12 ◽  
Author(s):  
W. J. Veith
Keyword(s):  
Surface Area ◽  
Yolk Sac ◽  
Nutrient Absorption ◽  
Progressive Reduction ◽  
Osmotic Adaptation ◽  
Epidermal Surface ◽  
Early Embryos ◽  
Hind Gut ◽  
Embryonic Structure ◽  
Scanning Electron

Autoradiographic studies reveal that embryos of Clinus superciliosus absorb nutrients from the embryotrophe secreted by the follicular wall. The embryonic structure active in nutrient absorption is the epidermis including that of the fins and the gut. Absorption initially takes place mainly through the epidermis, with the pericardial and yolk-sac areas being the most active. In prepartum embryos most of the nutrient absorption takes place through the gut. Embryonic exchange surfaces of C. superciliosus were studied by both light and scanning electron microscopy. Changes in absorptive activity during embryonic development were mirrored by changes in surface topography and intestinal anatomy. The relative surface area of early embryos is greatly increased by numerous epidermal macroridges, which are particularly abundant in the pericardial and yolk-sac areas, as well as by epidermal microvilli. With increase in embryo size, the macroridges are reduced in number, and finally disappear just prior to birth. However, the mid- and hind-gut areas hypertrophy during gestation. It is suggested that this hypertrophy compensates for the progressive reduction in epidermal surface area during development and that such reduction in surface area is a possible osmotic adaptation.

Distribution of diaphragmatic lymphatic stomata

1991 ◽  
Vol 70 (4) ◽  
pp. 1544-1549 ◽  
Author(s):  
D. Negrini ◽  
S. Mukenge ◽  
M. Del Fabbro ◽  
C. Gonano ◽  
G. Miserocchi
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Surface Area ◽  
Frequency Distribution ◽  
Maximum Diameter ◽  
Minimum Diameter ◽  
Average Value ◽  
Scanning Electron

In seven anesthetized rabbits we measured the size, shape, and density of lymphatic stomata on the peritoneal and pleural sides of the diaphragm. The diaphragm was fixed in situ and processed for scanning electron microscopy. Results are from 2,902 peritoneal and 3,086 pleural fields (each 1,620 microns 2) randomly chosen from the various specimens. Stomata were seen in 9% of the fields examined, and in 30% of the cases they appeared grouped in clusters with 2-14 stomata/field. Stoma density was 250 +/- 242 and 72 +/- 57 (SD) stomata/mm2 on peritoneal and pleural sides, respectively, and it was similar over the muscular and tendinous portion of the two surfaces. The maximum diameter ranged from less than 1 to approximately 30 microns, with an average value of 1.2 +/- 3.1 micron. The ratio of the maximum to the minimum diameter and the surface area averaged 2 +/- 1.4 and 0.7 +/- 2.4 micron 2, respectively. The maximum and minimum diameter and surface area values followed a lognormal frequency distribution, suggesting that stomata geometry is affected by diaphragmatic tension.

scholarly journals GuttaFlow Bioseal as Monocone Obturation Technique in Curved Root Canals: A Scanning Electron Microscopy Study

2021 ◽  
Vol 15 (2) ◽  
pp. 42-59
Author(s):  
Musliana Mustaffa ◽  
◽  
Hajar Ar Rahmah Nasri ◽  
Insyirah Kamarulzaman ◽  
Mohamad Shafiq Mohd Ibrahim ◽  
...  
Keyword(s):  
Surface Area ◽  
Root Canal ◽  
Current Approach ◽  
Filling Material ◽  
Sem Images ◽  
Root Canals ◽  
Gutta Percha ◽  
Curved Root Canals ◽  
Scanning Electron ◽  
Group 1

The obturation quality of GuttaFlow Bioseal in curved root canals is not commonly investigated although there has been a current approach toward utilizing this material in extracted molars in recent years. This study assessed the obturated surface area, extrusion of root filling material beyond the apical foramen and duration of obturation procedure in curved root canals using monocone obturation technique. Access cavity was prepared in 20 human mandibular molars. Root canals with curvature of more than 10 as determined according to Schneider’s method were included. Samples were prepared using Hyflex CM rotary files and divided into two groups (n=10): Group 1 [gutta-percha cone and GuttaFlow Bioseal] and Group 2 [gutta-percha cone and RoekoSeal Automix root canal sealer]. The duration of obturation procedure was recorded and obturation radiographs were taken. Samples were bisected and the mesial roots were sectioned horizontally to obtain 3 root segments; apical, middle and coronal. All resected roots were mounted on brass stubs, sputter-coated with thin platinum coating and observed under scanning electron microscope (SEM) at 70x magnification. The SEM images were transferred to the SketchAndCalc Area Calculator software. No statistically significant differences in the obturated surface area and extrusion of root filling material were observed between Group 1 and 2, irrespective of the status of root canal curvature. Duration for obturation in severe root canal curvatures between Group 1 and 2 were statistically significant. Obturated surface area and extrusion of root filling material were not affected by the root canal curvature, however duration for obturation using GuttaFlow Bioseal in severe root canal curvatures was slightly longer.

scholarly journals Micropore Structure and Fractal Characteristics of Low-Permeability Coal Seams

2018 ◽  
Vol 2018 ◽  
pp. 1-15 ◽  
Author(s):  
Guang-zhe Deng ◽  
Rui Zheng
Keyword(s):  
Fractal Dimension ◽  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
Coal Seam ◽  
Linear Relationship ◽  
Surface Area ◽  
Pore Volume ◽  
Low Permeability ◽  
Coal Seams ◽  
Scanning Electron

With the raw coal from a typical low-permeability coal seam in the coalfield of South Junger Basin in Xinjiang as the research object, this paper examined six kinds of coal samples with different permeabilities using a scanning electron microscope and a low-temperature nitrogen adsorption test that employed a JSM-6460LV high-resolution scanning electron microscope and an ASAP2020 automatic specific surface area micropore analyzer to measure all characteristic micropore structural parameters. According to fractal geometry theory, four fractal dimension calculation models of coal and rock were established, after which the pore structure characteristic parameters were used to calculate the fractal dimensions of the different coal seams. The results show that (1) the low-permeability coal seam in the coalfield of South Junger Basin in Xinjiang belongs to mesoporous medium, with a certain number of large pores and no micropores. The varying adsorption capacities of the different coal seams were positively correlated with pore volume, surface area, and the mesoporous surface area proportions, from which it was concluded that mesopores were the main contributors to pore adsorption in low-permeability coal seams. (2) The raw coal pore fractal dimension had a negative linear relationship to average pore size, a positive linear relationship with total pore volume, total surface area, and adsorption capacity, and a positive correlation with the mesoporous surface area proportion; that is, the higher the fractal dimension, the larger the pore volume and surface area of the raw coal. (3) The permeability of the low-permeability coal seam had a phase correlation with the micropore development degree; that is, the permeability had a phase negative correlation with the pore distribution fractal dimension, and there was a positive correlation between permeability and porosity. These results are of theoretical significance for the clean exploitation of low-permeability coal seam resources.

Characterization of Pacemaker Electrode Surfaces Utilizing Scanning Electron Microscopy (SEM) and In-Vitro Electrochemical Analysis

1999 ◽  
Vol 5 (S2) ◽  
pp. 402-403
Author(s):  
Scott Brabec ◽  
Bill Schindeldecker ◽  
Ken Brennen ◽  
Sue Okerstrom ◽  
Ky Pham
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Surface Area ◽  
Impedance Spectrum ◽  
Sample Surface ◽  
Electrochemical Analysis ◽  
Platinum Black ◽  
Conductive Surface ◽  
Scanning Electron

The efficiency of implantable electrodes for cardiac pacing depends on the ratio of the conductive surface area to the geometric area of the interface with excitable tissue. New models of heart pacers require reduction of post-pulse polarization, i.e. the potential left on the electrode / tissue interface after a pacemaker pulse. Increasing the conductive surface area is an effective method to this end. Microscopy provides an important tool in elucidating the role of surface structure in electrode performance.Three different surface textures were characterized on a 90% platinum(Pt)/10% iridium (Ir) polished electrode substrate of roughly 5 mm2 geometric surface area. These consisted of the polished substrate itself, a thin film of textured platinum in the 1-3 micron size range, and a sub-micron platinum black coating. Sample surface effects were characterized via scanning electron microscopy (SEM), in-vitro electrical impedance spectrum analysis, and polarization after-potential measurements.

scholarly journals Kesetimbangan Adsorpsi Zat Warna Methyl Violet Oleh Karbon Aktif Berbasis Limbah Daun Nanas (Ananas comosus L)

METANA ◽  
2018 ◽  
Vol 14 (2) ◽  
pp. 31
Author(s):  
Lanjar Lanjar ◽  
Fatma Indah Riayanti ◽  
Widi Astuti
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Fourier Transform ◽  
Surface Area ◽  
Methyl Violet ◽  
Fourier Transform Infrared ◽  
Ananas Comosus ◽  
Ftir Spectrometer ◽  
Model Isotherm ◽  
Scanning Electron

Industri tekstil semakin berkembang seiring dengan pertumbuhan penduduk di Indonesia. Selain memberikan manfaat, industri tekstil  memberikan dampak negatif bagi lingkungan akibat penggunaan zat warna sintetis, salah satunya yaitu methyl violet. Apabila limbah tersebut dibuang ke perairan akan menyebabkan rusaknya ekologi lingkungan dan ancaman bagi kesehatan manusia, karena sebagian besar zat warna bersifat sukar terurai (non-bidegradable) dan karsinogenik (Brono, 2010). Salah satu metode yang terbukti efektif untuk menghilangkan zat warna adalah adsorpsi menggunakan karbon aktif. Pada penelitian ini karbon aktif dibuat dari limbah daun nanas dengan aktivator ZnCl2 dan pemanasan gelombang mikro. Selanjutnya, karbon aktif tersebut dikarakteriasi morfologi permukaan menggunakan Scanning Electron Microscopy (SEM), luas permukaan menggunakan Surface Area Analyzer, dan analisis gugus fungsi menggunakan Fourier Transform Infrared (FTIR) spectrometer, dan digunakan untuk menjerap methyl violet di larutan. Hasil penelitian menunjukkan bahwa karbon aktif dari limbah daun nanas yang teraktivasi ZnCl2 menghasilkan pori yang lebih besar dibandingkan dengan karbon tanpa aktivasi serta memiliki gugus fungsi yang dapat menjerap methyl violet. Kondisi optimum untuk adsorpsi adalah pH 5, waktu kontak 90 menit, dan konsentrasi awal 500 mg/L. Model kesetimbangan yang sesuai yaitu menggunakan model isotherm freundlich.

Scanning electron microscopy and surface area studies of calcined ZnCrCl layered doubled hydroxides

1995 ◽  
Vol 14 (24) ◽  
pp. 1747-1750 ◽  
Author(s):  
M. Zobir Hussein ◽  
Z. Zainal ◽  
H. H. Swee
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Surface Area ◽  
Area Studies ◽  
Scanning Electron

scholarly journals Enhanced Hydrophilic and Electrophilic Properties of Polyvinyl Chloride (PVC) Biofilm Carrier

Polymers ◽  
2020 ◽  
Vol 12 (6) ◽  
pp. 1240
Author(s):  
Haifeng Cai ◽  
Yang Wang ◽  
Kai Wu ◽  
Weihong Guo
Keyword(s):  
Contact Angle ◽  
Zinc Oxide ◽  
Surface Area ◽  
Polyvinyl Chloride ◽  
Positive Charge ◽  
Sem Images ◽  
Biofilm Carrier ◽  
Surface Contact Angle ◽  
Bacterial Adsorption ◽  
Scanning Electron

Polyvinyl chloride (PVC) biofilm carrier is used as a carrier for bacterial adsorption in wastewater treatment. The hydrophilicity and electrophilicity of its surface play an important role in the adsorption of bacteria. The PVC biofilm carrier was prepared by extruder, and its surface properties were investigated. In order to improve the hydrophilicity and electrophilic properties of the PVC biofilm carrier, polyvinyl alcohol (PVA) and cationic polyacrylamide (cPAM) were incorporated into polyvinyl chloride (PVC) by blending. Besides, the surface area of the PVC biofilm carrier was increased by azodicarbonamide modified with 10% by weight of zinc oxide (mAC). The surface contact angle of PVC applied by PVA and cPAM at 5 wt %, 15 wt % was 81.6°, which was 18.0% lower than pure PVC. It shows the significant improvement of the hydrophilicity of PVC. The zeta potential of pure PVC was −9.59 mV, while the modified PVC was 14.6 mV, which proves that the surface charge of PVC changed from negative to positive. Positive charge is more conducive to the adsorption of bacteria. It is obvious from the scanning electron microscope (SEM) images that holes appeared on the surface of the PVC biofilm carrier after adding mAC, which indicates the increase of PVC surface area.

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