scholarly journals SINTESIS NANOKOMPOSIT Nata de coco/TiO2/Ag DAN EFEKTIVITASNYA SEBAGAI ANTIBAKTERI TERHADAP BAKTERI Escherichia coli dan Staphylococcus aureus

2021 ◽  
Vol 14 (1) ◽  
Author(s):  
Heriyanto Tinentang ◽  
Henry F Aritonang ◽  
Harry S. J. Koleangan

Telah dilakukan penelitian tentang kemampuan aktivitas anti bakteri untuk bakteri Staphylococcus aureus (gram positif) dan Escherichia coli (gram negatif) dengan menggunakan nanokomposit nata de coco/TiO2, nata de coco/Ag, dan nata de coco/TiO2/Ag dengan variasi konsentrasi Ag 0,5 M; 0,6 M; 0,7 M; 0,8 M dan 0,9 M  menggunakan metode reduksi kimia. Nanopartikel tersebut dikarakterisasi menggunakan X-Ray Diffractometry (XRD), scanning electron microscopy-energy dispersive X-ray spectroscopy  (SEM-EDS) dan anti bakteri. Untuk uji aktivitas antibakteri menggunakan metode kertas cakram dan dilakukan sebanyak dua kali ulangan untuk tiap-tiap sampel dan bakteri yang diuji. Hasil penelitian menunjukan, aktivitas anti bakteri nanokomposit yang paling baik dalam menghambat pertumbuhan bakteri adalah nanokomposit Nata de coco/TiO2/Ag mampu menghambat pertumbuhan bakteri Escherichiacoli dan Staphylococcusaureus, namun nanokomposit tersebut lebih efektif menghambat pertumbuhan bakteri Escherichiacoli.ABSRACT Research on the ability of anti-bacterial activity for Staphylococcus aureus (gram positive) and Escherichia coli (gram negative) bacteria using nata de coco / nanocomposites TiO2, nata de coco / Ag, and nata de coco / TiO2 / Ag with variations of Ag 0,5 M; 0.6 M; 0.7 M; 0.8 M and 0.9 M using the chemical reduction method. Nanoparticles were characterized using X-Ray Diffractometry (XRD), scanning electron microscopy-energy dispersive X-ray spctroscopy  (SEM-EDS) and anti-bacterial actvity. Test the antibacterial activity using the paper disc method and repeated two times for each sample and bacteria tested. The results showed that the good anti-bacterial activity of nanocomposites in inhibiting bacterial growth was nanocomposite nata de coco /TiO2/Ag  able to inhibit the growth of Escherichia coli and S. aureus, but the nanocomposite is more effective in inhibiting the growth of Escherichia  coli bacteria.

2020 ◽  
Vol 90 (21-22) ◽  
pp. 2492-2503
Author(s):  
MA Mousa ◽  
M Khairy

A liquid precipitation method was used to prepare zinc oxide nanoparticles in three diverse media: water, methanol, and ethylene glycol. The studied materials were examined by scanning electron microscopy, X-ray diffraction, Fourier transform infrared spectroscopy, and ultraviolet-visible spectroscopy. X-ray diffraction patterns showed a hexagonal Wurtzite structure of zinc oxide with a nanocrystalline size. Acquired powders showed different morphologies (rod, star, and spherical structures), which were affected by the nature of the solvent in the reaction. The different zinc oxide powders have varied optical band gaps. Scanning electron microscopy examinations confirmed the arrangement of nano-zinc oxide on the surfaces of the materials. The zinc oxide-covering procedure was carried out on cotton, polyester, and 50/50 wt% polyester/cotton blended fabrics using a simple dip and curing system. The cotton fabric treated with nanorod zinc oxide exhibited the highest ultraviolet protection factor with a value of 247.2. The antimicrobial properties of untreated and treated fabrics with nano-zinc oxide were measured against Gram-negative bacteria (Escherichia coli), Gram-positive bacteria (Staphylococcus aureus), and diploid fungus (Candida albicans). The results showed the antimicrobial action relies on the morphological structure and the particle size of zinc oxide and that it increases with a reduced particle size. The cotton fabric treated with 26 nm nonspherical zinc oxide particles showed the highest antimicrobial efficiency with values of 91.4%, 86.8%, and 84.7% for Staphylococcus aureus, Escherichia coli, and Candida albicans, respectively. The mechanical properties of treated fabrics were studied. The results confirm that nano-zinc oxide is highly useful for improving the performance of defense textile products because of its biocompatibility, environmental friendliness, and nontoxicity.


2018 ◽  
Vol 21 (7) ◽  
pp. 495-500 ◽  
Author(s):  
Hassan A. Almarshad ◽  
Sayed M. Badawy ◽  
Abdalkarem F. Alsharari

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.


2003 ◽  
Vol 18 (9) ◽  
pp. 2050-2054 ◽  
Author(s):  
Marcello Gombos ◽  
Vicente Gomis ◽  
Anna Esther Carrillo ◽  
Antonio Vecchione ◽  
Sandro Pace ◽  
...  

In this work, we report on the observation of Nd1Ba6Cu3O10,5 (Nd163) phase of the NdBaCuO system in melt-textured Nd123 bulk samples grown from a mixture of Nd123 and Nd210 phase powders. The observation was performed with polarized light optical microscopy and scanning electron microscopy–energy dispersive x-ray analyses. Images of the identified phase crystals show an aspect quite different from Nd422 crystals. Unexpectedly, Nd163 was individuated, even in “pure” Nd123 samples. Moreover, after long exposure to air, Nd163 disappeared completely in samples synthesized from powders containing Nd210. Thermogravimetry analyses of powders show that the stability of this phase in air is limited to temperatures higher than 900 °C, so Nd163 is unstable and highly reactive at room temperature. Moreover, an explanation of the observation of Nd163 in Nd210 free samples, based on the spontaneous formation of Nd163 phase in a Nd123 melt, is proposed.


Author(s):  
Congmin Li ◽  
Yanguo Yin ◽  
Ming Xu ◽  
Jianfeng Cheng ◽  
Lan Shen ◽  
...  

Abstract The microstructures of an Al-Bi immiscible alloy and the corresponding composites containing TiC (1 wt.% and 2 wt.%) were explored for melt temperatures of 800 °C, 850 °C, and 900°C. It was demonstrated that serious coarsening and macrosegregation of Bi-rich minority phase particles occurred, which was slightly alleviated by increasing the melt temperature from 800 °C to 900 °C. By adding TiC particles, the coarsening and macrosegregation of Bi-rich minority phase particles were significantly impeded. Scanning electron microscopy and energy-dispersive X-ray spectroscopy revealed that TiC particles were located inside and on the surface of Bi-rich minority phase particles, exhibiting heterogeneous nucleation and self-assembly behaviour. By properly increasing the holding time of the melt, finer and more uniform Bi-rich minority phase particles were obtained.


2014 ◽  
Vol 20 (5) ◽  
pp. 1534-1543 ◽  
Author(s):  
Annalaura Restivo ◽  
Ilaria Degano ◽  
Erika Ribechini ◽  
Josefina Pérez-Arantegui ◽  
Maria Perla Colombini

Abstract:An innovative approach, combining field-emission scanning electron microscopy (FESEM) with energy dispersive X-ray spectroscopy (EDX) analysis, is presented to investigate the degradation mechanisms affecting tannin-dyed wool. In fact, tannin-dyed textiles are more sensitive to degradation then those dyed with other dyestuffs, even in the same conservation conditions.FESEM-EDX was first used to study a set of 48 wool specimens (artificially aged) dyed with several raw materials and mordants, and prepared according to historical dyeing recipes. EDX analysis was performed on the surface of wool threads and on their cross-sections. In addition, in order to validate the model formulated by the analysis of reference materials, several samples collected from historical and archaeological textiles were subjected to FESEM-EDX analysis.FESEM-EDX investigations enabled us to reveal the correlation between elemental composition and morphological changes. In addition, aging processes were clarified by studying changes in the elemental composition of wool from the protective cuticle to the fiber core in cross-sections. Morphological and elemental analysis of wool specimens and of archaeological and historical textiles showed that the presence of tannins increases wool damage, primarily by causing a sulfur decrease and fiber oxidation.


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