scholarly journals Nacre morphology and chemical composition in Atlantic winged oyster Pteria colymbus (Röding, 1798)

PeerJ ◽  
2021 ◽  
Vol 9 ◽  
pp. e11527
Author(s):  
Pablo Santana ◽  
Dalila Aldana Aranda
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Calcium Carbonate ◽  
Organic Matrix ◽  
Carbonyl Groups ◽  
X Ray Diffraction ◽  
Mineral Phase ◽  
X Ray ◽  
Minor Elements ◽  
Scanning Electron

The microstructure and nanostructure of nacre in Pteria colymbus were studied with high-resolution field emission scanning electron microscopy (FESEM). The tablets were found to be flat and polyhedral with four to eight sides, and lengths ranging from 0.6 to 3.0 µm. They consisted of nanocrystals 41 nm wide, growing in the same direction. X-ray diffraction showed the crystals to be mineral phase aragonite, which was confirmed by Raman spectroscopy. Fourier transform infrared spectroscopy identified a band at 1,786.95 cm−1 attributed to carboxylate (carbonyl) groups of the proteins present in the organic matrix as well as bands characteristic of calcium carbonate. X-ray fluorescence showed the nacre to contain 98% calcium carbonate, as well as minor elements (Si, Na, S and Sr) and trace elements (Mg, P, Cu, Al, Fe, Cl, K and Zn).

Synthesis of Precipitate Calcium Carbonate with Variation Morphology from Limestone by Using Solution Mixing Method

2019 ◽  
Vol 966 ◽  
pp. 200-203
Author(s):  
Zaenal Arifin ◽  
Triwikantoro ◽  
Bintoro Anang Subagyo ◽  
Mochamad Zainuri ◽  
Darminto
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Calcium Carbonate ◽  
Molar Ratio ◽  
Mixing Process ◽  
X Ray Diffraction ◽  
Precipitate Calcium Carbonate ◽  
X Ray ◽  
Mixing Method ◽  
Scanning Electron

Abstract. In this study, the CaCO3 powder has been successfully synthesized by mixing CaCl2 from natural limestone and Na2CO3 in the same molar ratio. The mixing process of solutions was carried out by employing the molar contents of 0.125, 0.25, 0.375 and 0.5M at varying temperatures of 30, 40, 60 and 80ᴼC. The produced CaCO3 microparticles were characterized by scanning electron microscopy (SEM) and X-ray diffraction (XRD). The highest content of aragonite phase with morphology rod-like of the samples is around 29 wt%, resulting from the process using solution of 0.125 M at 80 ᴼC. While at 30 ᴼC and 40 ᴼC produced 100 wt% calcite phase.

Characterization of Diatomite, Leonardite and Pumice

2016 ◽  
Vol 872 ◽  
pp. 211-215 ◽  
Author(s):  
Pusit Pookmanee ◽  
Atit Wannawek ◽  
Sakchai Satienperakul ◽  
Ratchadapon Putharod ◽  
Nattapol Laorodphan ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Functional Group ◽  
Chemical Compositions ◽  
Carbonyl Groups ◽  
X Ray Diffraction ◽  
X Ray ◽  
Properties Of Materials ◽  
Scanning Electron

This research studies compositions of diatomite, leonardite and pumice for utilization appropriate to the properties of materials. Chemical compositions of these materials were characterized by X–ray fluorescence spectrometry (XRF) and energy dispersive X–ray spectrometry (EDXS). The silica was major component of these materials. The morphology was investigated by scanning electron microscopy (SEM). Diatomite was cylindrical in shape, leonardite was sheet or flake in shape and pumicewas prismatic in shape. The structure was studied by X–ray diffraction (XRD). It was found that the mineral composition of diatomite, leonardite and pumice showed cristobalite low, quartz and anorthite, respectively. The functional groups were identified by Fourier transform infraredspectrometry (FTIR). The functional group of siloxane was obtained and dominated vibration in these materials. And the vibration of carboxylic, alcoholic and carbonyl groups were obtained in leonardite.

Influence of Inorganic Ion on the Synthesis of Hollow Calcium Carbonate

2006 ◽  
Vol 11-12 ◽  
pp. 677-680 ◽  
Author(s):  
Gunawan Hadiko ◽  
Yong Sheng Han ◽  
Masayoshi Fuji ◽  
Minoru Takahashi
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Calcium Carbonate ◽  
Room Temperature ◽  
Hollow Structure ◽  
X Ray Diffraction ◽  
X Ray ◽  
Inorganic Ion ◽  
Potential Component ◽  
Scanning Electron

Hollow calcium carbonate (CaCO3) particles were synthesized by bubbling CO2 in the solution of calcium chloride (CaCl2) with the presence of ammonia at room temperature. Hollow calcium carbonate is a potential component to be used as pharmaceuticals, agrochemicals, and catalysis. This paper investigated the effect of additive on the hollow structure. In this study was used vanadate ion as additive agent. Physical characteristics of precipitate were evaluated using scanning electron microscopy (SEM) and X-ray diffraction (XRD).

Influence Factors of Calcium Carbonate Whiskers Prepared by Intermittent Bubbling Method

2013 ◽  
Vol 310 ◽  
pp. 80-84 ◽  
Author(s):  
Bei Ping Liu ◽  
Jian Chen ◽  
Fang Bo Liu ◽  
Shi Biao Zhou ◽  
Yuan Dao Chen ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Calcium Carbonate ◽  
Aspect Ratio ◽  
Smooth Surface ◽  
Influence Factors ◽  
Large Aspect Ratio ◽  
X Ray Diffraction ◽  
X Ray ◽  
Scanning Electron

Calcium carbonate whiskers were successfully prepared in the MgC12-Ca(OH)2-CO2 system by a intermittent bubbling method and characterized by X-ray diffraction and scanning electron microscopy. The results demonstrated that aragonite style calcium carbonate whiskers with well morphology, large aspect ratio and smooth surface can be obtained by controlling technical conditions such as reaction temperature, concentration of Ca(OH)2 and amount of additives and under the conditions of CO2 flow velocity of 3.4ml/min/gCa(OH)2, flow of CO2 to air ratio of 1:4, stirring speed of 240 r/min.

Composition and Microstructures of Imperial Brass Chinese Coins

2010 ◽  
Vol 636-637 ◽  
pp. 531-537 ◽  
Author(s):  
M.J. Furtado ◽  
Rui Jorge C. Silva ◽  
M.F. Araújo ◽  
Francisco Manuel Braz Fernandes
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Equilibrium Phase ◽  
Energy Dispersive ◽  
X Ray Diffraction ◽  
X Ray ◽  
Fine Grained ◽  
Minor Elements ◽  
Brass Alloys ◽  
Scanning Electron

Twenty brass Chinese cash coins with complex compositions were studied for a better understanding of the metallurgical cash production in China, during the 17th, 18th and 19th centuries. Elemental composition was obtained through energy-dispersive micro X-ray fluorescence spectrometry of small cleaned areas on the coins rims. Results showed that these brass alloys (Cu-Zn) frequently contain up to 3% Sn, have highly variable Pb content (from n.d. up to 14%) and Fe, Sb, and As as minor elements. Microstructures were assessed by optical microscopy, scanning electron microscopy with energy dispersive spectroscopy, and preliminary micro X-ray diffraction analysis. All the coins present typical as-cast microstructures although very fine-grained, which are supported by binary (Cu-Zn) and ternary (Cu-Zn-Sn) equilibrium phase diagrams, that explain microstructural differences due to the presence of Sn in these brasses.

Identification of calcium oxalate crystals in dried or fixed tobacco leaf

1984 ◽  
Vol 42 ◽  
pp. 288-289
Author(s):  
Vicki L. Baliga ◽  
Mary Ellen Counts
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Calcium Oxalate ◽  
Growth And Development ◽  
Polarized Light ◽  
Calcium Oxalate Crystals ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Scanning Electron

Calcium is an important element in the growth and development of plants and one form of calcium is calcium oxalate. Calcium oxalate has been found in leaf seed, stem material plant tissue culture, fungi and lichen using one or more of the following methods—polarized light microscopy (PLM), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and x-ray diffraction.Two methods are presented here for qualitatively estimating calcium oxalate in dried or fixed tobacco (Nicotiana) leaf from different stalk positions using PLM. SEM, coupled with energy dispersive x-ray spectrometry (EDS), and powder x-ray diffraction were used to verify that the crystals observed in the dried leaf with PLM were calcium oxalate.

Environmental scanning electron microscopy of fresh human gallstones reveals new morphologies of precipitated calcium salts

1992 ◽  
Vol 50 (2) ◽  
pp. 1322-1323
Author(s):  
Howard S. Kaufman ◽  
Keith D. Lillemoe ◽  
John T. Mastovich ◽  
Henry A. Pitt
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Environmental Scanning Electron Microscopy ◽  
Environmental Scanning ◽  
X Ray Diffraction ◽  
Calcium Salts ◽  
Cholesterol Gallstones ◽  
X Ray ◽  
Ca Carbonate ◽  
Scanning Electron

Gallstones contain precipitated cholesterol, calcium salts, and proteins. Calcium (Ca) bilirubinate, palmitate, phosphate, and carbonate occurring in gallstones have variable morphologies but characteristic windowless energy dispersive x-ray (EDX) spectra. Previous studies of gallstone microstructure and composition using scanning electron microscopy (SEM) with EDX have been limited to dehydrated samples. In this state, Ca bilirubinates appear as either glassy masses, which predominate in black pigment stones, or as clusters, which are found mostly in cholesterol gallstones. The three polymorphs of Ca carbonate, calcite, vaterite, and aragonite, have been identified in gallstones by x-ray diffraction, however; the morphologies of these crystals vary in the literature. The purpose of this experiment was to study fresh gallstones by environmental SEM (ESEM) to determine if dehydration affects gallstone Ca salt morphology.Gallstones and bile were obtained fresh at cholecystectomy from 6 patients. To prevent dehydration, stones were stored in bile at 37°C. All samples were studied within 4 days of procurement.

PENINGKATAN LAJU DISOLUSI ACYCLOVIR DENGAN METODE SISTEM DISPERSI PADAT MENGGUNAKAN POLOXAMER 188

2016 ◽  
Vol 5 (1) ◽  
pp. 6
Author(s):  
Budi Setiawan ◽  
Erizal Zaini ◽  
Salman Umar
Keyword(s):  
Electron Microscopy ◽  
Thermal Analysis ◽  
Scanning Electron Microscopy ◽  
Fourier Transform ◽  
Differential Thermal Analysis ◽  
Fourier Transform Infrared ◽  
X Ray Diffraction ◽  
Poloxamer 188 ◽  
X Ray ◽  
Scanning Electron

Sebuah penelitian tentang sistem dispersi padat dari asiklovir dengan poloxamer 188 telah dilakukan formulasi dengan pencampuran secara fisika dengan rasio 1 : 1, 1 : 3, 1 : 5 dan dispersi padat 1 : 1, 1 : 3, 1 : 5 dan penggilingan 1:1 sebagai pembanding. Dispersi padat dibuat menggunakan metode pencairan (fusi), yang digabung dengan poloxamer 188 pada hotplate kemudian asiklovir dimasukkan ke dalam hasil poloxamer 188 lalu di kocok hingga membentuk masa homogen. Semua formula yang terbentuk termasuk asiklovir poloxamer 188 murni dianalisis karakterisasinya dengan Differential Thermal Analysis (DTA), X-ray Diffraction, Scanning Electron Microscopy (SEM), dan Fourier Transform Infrared (FTIR), kemudian pengambilan dilakukan  (penentuan kadar) mengunakan spektrofotometer UV pada panjang gelombang 257,08 nm dan uji laju disolusi dengan aquadest bebas CO2 menggunakan metode dayung. Hasil pengambilan  (penentuan kadar) menunjukkan bahwa semua formula memenuhi persyaratan farmakope Amerika edisi 30 dan farmakope Indonesia edisi 4 yaitu 95-110%. Sedangkan hasil uji laju disolusi untuk campuran fisik 1: 1, dan dispersi padat 1: 1, dan penggilingan 1: 1 menunjukkan peningkatan yang nyata dibandingkan asiklovir murni. Hal ini juga dapat dilihat dari hasil perhitungan statistik  menggunakan analisis varian satu arah  SPSS 17.

Structural Characterization of Gallbladder Stones Using Energy Dispersive X-ray Spectroscopy and X-ray Diffraction

2018 ◽  
Vol 21 (7) ◽  
pp. 495-500 ◽  
Author(s):  
Hassan A. Almarshad ◽  
Sayed M. Badawy ◽  
Abdalkarem F. Alsharari
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Energy Dispersive ◽  
Spectroscopic Techniques ◽  
X Ray Diffraction ◽  
Major Health Problem ◽  
X Ray ◽  
Gallbladder Stones ◽  
Pure Cholesterol ◽  
Scanning Electron

Aim and Objective: Formation of the gallbladder stones is a common disease and a major health problem. The present study aimed to identify the structures of the most common types of gallbladder stones using X-ray spectroscopic techniques, which provide information about the process of stone formation. Material and Method: Phase and elemental compositions of pure cholesterol and mixed gallstones removed from gallbladders of patients were studied using energy-dispersive X-ray spectroscopy combined with scanning electron microscopy analysis and X-ray diffraction. Results: The crystal structures of gallstones which coincide with standard patterns were confirmed by X-ray diffraction. Plate-like cholesterol crystals with laminar shaped and thin layered structures were clearly observed for gallstone of pure cholesterol by scanning electron microscopy; it also revealed different morphologies from mixed cholesterol stones. Elemental analysis of pure cholesterol and mixed gallstones using energy-dispersive X-ray spectroscopy confirmed the different formation processes of the different types of gallstones. Conclusion: The method of fast and reliable X-ray spectroscopic techniques has numerous advantages over the traditional chemical analysis and other analytical techniques. The results also revealed that the X-ray spectroscopy technique is a promising technique that can aid in understanding the pathogenesis of gallstone disease.

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