scholarly journals Nano Scale Hydroxyapatite from Crassostreao virginica (Oyster Seashells) and its Modification with Azadirachta Indica (Neem) Extract

2018 ◽  
Vol 15 (3) ◽  
pp. 296-306
Author(s):  
R. Usha ◽  
S. Sudhaparimala

Hydroxyapatite (HAp) is a widely explored biomaterial for bone and tooth replacements. Most of the research studies are being carried out in terms of novel routes of synthesis and fabrication in the nano scale to suit its applications. The present research study is unique in two aspects one being the use of seawaste namely Crassostreao virginica (Oyster) seashells as the source of calcium carbonate along with phosphoric acid and in the alkaline pH to synthesize nano sized HAp and secondly to check the enhanced activity of HAp if any, upon the addition of Azadirachta indica Extract (neem leaf and neem stem) by wet precipitation method. The structural activity relationship of assynthesised HAp sample was compared with that of the modified HAp using Azadirachta indica extract as medium. The presence of Hexagonal phase (JCPDS no-09-0432) was identified in all HAp samples. The crystallite size of 38nm was observed in the HAP prepared from the seashell in comparison with the crystallite of 49 nm (neem leaf) and 52mm (neem stem) modified HAp. The presence of spherical morphology and elemental composition of Ca,P in HAp and modified HAps were identified from Scanning Electron Microscopic images. The toxicity studies of assynthesised HAp and modified HAp with Azadirachta indica against Candida albicans and Streptococcus mutans were compared and the results were encouraging. This study ultimately provided a simple, cost effective green method of converting seawaste into high value biomedical product of nanoscale hydroxyapatite with enhanced antimicrobial activity.

Author(s):  
San San Htwe ◽  
Sanda Win ◽  
Myint Myint Swe ◽  
Sandar Win

In modern science Nanotechnology is the field for the researchers. Nanoparticles have a size of 1-100 nm with a surrounding interfacial layer. Many researchers characterize significantly concerning medical chemistry, atomic physics, and all other known fields. Zinc oxide nanoparticles were synthesized with precipitation method after annealing the precursor at different temperatures. The effects of annealing temperatures for the precursors on the particle size of ZnO NPs were investigated. The structure and composition of the precursor and prepared ZnO NPs will study using X-ray diffraction (XRD), Scanning Electron Microscopic Analysis (SEM), and the optical properties of the ZnO NPs will characterize using UV-visible spectroscopy.


2019 ◽  
Vol 6 (1) ◽  
pp. 23-24
Author(s):  
Vidhya P ◽  
Ranjitha A ◽  
Balaganesh A.S ◽  
RanjitKumar R ◽  
Chandar Shekar B

Cadmium Sulfide nanoparticles were prepared by a simple and cost effective precipitation method. Xray analysis revealed broad diffraction peaks indicating that the particles are of very small size. The prominent broad peaks at 2θ values of 26.48°, 43.90°, and 51.91°, which could be indexed to the (002), (110) and (112) direction of the hexagonal phase of CdS. Optical studies showed maximum absorbance in the UV region but minimum absorbance in the VIS-NIR regions make it an excellent material for screening off UV portion of electromagnetic spectrum in UV filters and sensors.


Author(s):  
Toichiro Kuwabara

Although scanning electron microscopy has a great potential in biological application, there are certain limitations in visualization of the biological structure. Satisfactory techniques to demonstrate natural surfaces of the tissue and the cell have been reported by several investigators. However, it is commonly found that the surface cell membrane is covered with a minute amount of mucin, secretory substance or tissue fluid as physiological, pathological or artefactual condition. These substances give a false surface appearance, especially when the tissue is fixed with strong fixatives. It seems important to remove these coating substances from the surface of the cell for demonstration of the true structure.


Author(s):  
T. Kanetaka ◽  
M. Cho ◽  
S. Kawamura ◽  
T. Sado ◽  
K. Hara

The authors have investigated the dissolution process of human cholesterol gallstones using a scanning electron microscope(SEM). This study was carried out by comparing control gallstones incubated in beagle bile with gallstones obtained from patients who were treated with chenodeoxycholic acid(CDCA).The cholesterol gallstones for this study were obtained from 14 patients. Three control patients were treated without CDCA and eleven patients were treated with CDCA 300-600 mg/day for periods ranging from four to twenty five months. It was confirmed through chemical analysis that these gallstones contained more than 80% cholesterol in both the outer surface and the core.The specimen were obtained from the outer surface and the core of the gallstones. Each specimen was attached to alminum sheet and coated with carbon to 100Å thickness. The SEM observation was made by Hitachi S-550 with 20 kV acceleration voltage and with 60-20, 000X magnification.


Author(s):  
S. K. Pena ◽  
C. B. Taylor ◽  
J. Hill ◽  
J. Safarik

Introduction: Oxidized cholesterol derivatives have been demonstrated in various cell cultures to be very potent inhibitors of 3-hvdroxy-3- methylglutaryl Coenzyme A reductase which is a principle regulator of cholesterol biosynthesis in the cell. The cholesterol content in the cells exposed to oxidized cholesterol was found to be markedly decreased. In aortic smooth muscle cells, the potency of this effect was closely related to the cytotoxicity of each derivative. Furthermore, due to the similarity of their molecular structure to that of cholesterol, these oxidized cholesterol derivatives might insert themselves into the cell membrane, alter membrane structure and function and eventually cause cell death. Arterial injury has been shown to be the initial event of atherosclerosis.


Author(s):  
Loren Anderson ◽  
Pat Pizzo ◽  
Glen Haydon

Transmission electron microscopy of replicas has long been used to study the fracture surfaces of components which fail in service. Recently, the scanning electron microscope (SEM) has gained popularity because it allows direct examination of the fracture surface. However, the somewhat lower resolution of the SEM coupled with a restriction on the sample size has served to limit the use of this instrument in investigating in-service failures. It is the intent of this paper to show that scanning electron microscopic examination of conventional negative replicas can be a convenient and reliable technique for determining mode of failure.


Author(s):  
Peter M. Andrews

Although there have been a number of recent scanning electron microscopic reports on the renal glomerulus, the advantages of scanning electron microscopy have not yet been applied to a systematic study of the uriniferous tubules. In the present investigation, scanning electron microscopy was used to study the ultrastructural morphology of the proximal, distal, thin loop, and collecting tubules. Material for observation was taken from rat kidneys which were fixed by vascular perfusion, sectioned by either cutting or fracturing technigues, and critically point dried.The brush border characterising proximal tubules is first detected on the luminal surface of Bowman's capsule adjacent to the urinary pole orifice. In this region one frequently finds irregular microvilli characterized by broad and flattened bases with occasional bulbous structures protruding from their surfaces.


Author(s):  
D.J. Lim ◽  
W.C. Lane

The morphology and function of the vestibular sensory organs has been extensively studied during the last decade with the advent of electron microscopy and electrophysiology. The opening of the space age also accelerated active investigation in this area, since this organ is responsible for the sensation of balance and of linear, angular and gravitational acceleration.The vestibular sense organs are formed by the saccule, utricle and three ampullae of the semicircular canals. The maculae (sacculi and utriculi) have otolithic membranes on the top of the sensory epithelia. The otolithic membrane is formed by a layer of thick gelatin and sand-piles of calcium carbonate crystals (Fig.l).


Author(s):  
M.D. Graham

The recent development of the scanning electron microscope has added great impetus to the study of ultrastructural details of normal human ossicles. A thorough description of the ultrastructure of the human ossicles is required in order to determine changes associated with disease processes following medical or surgical treatment.Human stapes crura were obtained at the time of surgery for clinical otosclerosis and from human cadaver material. The specimens to be examined by the scanning electron microscope were fixed immediately in the operating room in a cold phosphate buffered 2% gluteraldehyde solution, washed with Ringers, post fixed in cold 1% osmic acid and dehydrated in graded alcohol. Specimens were transferred from alcohol to a series of increasing concentrations of ethyl alcohol and amyl acetate. The tissue was then critical point dried, secured to aluminum stubs and coated with gold, approximately 150A thick on a rotating stage in a vacuum evaporator. The specimens were then studied with the Kent-Cambridge S4-10 Scanning Electron Microscope at an accelerating voltage of 20KV.


Author(s):  
A. E. Hotchkiss ◽  
A. T. Hotchkiss ◽  
R. P. Apkarian

Multicellular green algae may be an ancestral form of the vascular plants. These algae exhibit cell wall structure, chlorophyll pigmentation, and physiological processes similar to those of higher plants. The presence of a vascular system which provides water, minerals, and nutrients to remote tissues in higher plants was believed unnecessary for the algae. Among the green algae, the Chaetophorales are complex highly branched forms that might require some means of nutrient transport. The Chaetophorales do possess apical meristematic groups of cells that have growth orientations suggestive of stem and root positions. Branches of Chaetophora incressata were examined by the scanning electron microscope (SEM) for ultrastructural evidence of pro-vascular transport.


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