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Novel Biomimatic Synthesis of ZnO Nanorods Using Egg White (Albumen) and Their Antibacterial Studies
Ahmed, Faheem,Arshi, Nishat,Jeong, Yeong Seung,Anwar, M. S.,Dwivedi, Saurabh,Alsharaeh, Edreese,Koo, B. H. American Scientific Publishers 2016 Journal of Nanoscience and Nanotechnology Vol.16 No.6
<P>Zinc oxide (ZnO) is well-recognized as a biocompatible multifunctional material with outstanding properties as well as low toxicity and biodegradability. In this work, a simple and versatile technique was developed to prepare highly crystalline ZnO nanorods by introducing egg white to a bio-inspired approach. X-ray diffraction (XRD) and selected area electron diffraction (SAED) pattern results indicated that the ZnO nanorods have single phase nature with the wurtzite structure. Field emission scanning electron microscopy (FESEM) and Transmission electron microscopy (TEM) results showed the nanometer dimension of the nanorods. Raman, FTIR, and TGA/DTA analyses revealed the formation of wurtzite ZnO. The antibacterial properties of ZnO nanorods were investigated using both Gram-positive and Gram-negative microorganisms. These studies demonstrate that ZnO nanorods have a wide range of antibacterial activities toward various microorganisms that are commonly found in environmental settings. Survival ratio of bacteria decreased with increasing powder concentration, i.e., increase in antibacterial activity. The antibacterial activity of the ZnO nanorods toward Pseudomonas aeruginosa was stronger than that of Escherichia coli and Staphylococcus aureus. Surprisingly, the antibacterial activity did not require specific UV activation using artificial lamps, rather activation was achieved under ambient lighting conditions. Overall, the experimental results suggest that ZnO nanorods could be developed as antibacterial agents against a wide range of microorganisms to control and prevent the spreading and persistence of bacterial infections. This research introduces a new concept to synthesize ZnO nanorods by using egg white as a biological template for various applications including food science, animal science, biochemistry, microbiology and medicine.</P>
Faheem Ahmed,샤런드라쿠마르,Nishat Arshi,M. S. Anwar,허시내,김근우,여준청,구본흔,Hoa Hong Nguyen 한국물리학회 2012 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.60 No.10
We report the observation of room temperature ferromagnetism in Cu-doped ZnO nanorods prepared by microwave irradiation technique. X-ray diffraction (XRD) and transmission electron microscopy (TEM) results showed that Cu-doped ZnO comprise a single phase nature with wurtzite structure and Cu ions were successfully incorporated into the lattice position of Zn ions in ZnO matrix. Field emission scanning electron microscopy (FESEM) and TEM micrographs suggested that the size of Cu-doped ZnO nanorods ranges from 50 to 70 nm in diameter and 300 to 400 nm in length, respectively. The selected area electron diffraction (SAED) pattern infer that the Cu-ZnO nanorods have single phase nature with preferentially growth direction along [0 0 1] plane. Raman scattering spectra of Cu-doped ZnO nanorods revealed the blue shift of <I>E<SUB>2</SUB></I><SUP>high</SUP> mode that is related to the vibration of oxygen atoms in wurtzite ZnO, suggested the successful doping of Cu at Zn site into ZnO. Magnetization measurements showed that the nanorods exhibit room temperature ferromagnetism.
FAHEEM AHMED,Nishat Arshi,M. S. ANWAR,Rehan Danish,구본흔 한국물리학회 2013 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.62 No.10
Herein, the effect of different TM (Co, Ni and Cu) doping on structural, optical and magnetic properties of ZnO nanostructures has been studied. Zn1−xTMxO (TM=Co, Ni and Cu) nanostructures were prepared by a microwave assisted chemical route and characterized by X-ray diffraction (XRD), field emission scanning electron microscopy, transmission electron microscopy (TEM), Raman spectroscopy, UV-Vis and magnetization measurements. XRD and TEM analyses showed that the TM-doped ZnO nanostructures had single phase nature with the wurtzite structure. Changes in the lattice volume, bandgap energy, morphology and the saturation magnetization of Zn1−xTMxO nanostructures were found to be dependent on the type of TM dopants. Lattice volume, bondlength and bandgap determined from XRD and UV-Vis, respectively, were found to decrease as the atomic number of the dopant increased from Co to Cu. Magnetic studies showed that all the TM-doped ZnO exhibited room temperature ferromagnetism and the decreasing trend of saturation magnetization was observed with the increase of 3d electrons number from Co to Cu.
Magnetic, Optical and Structural Property Studies of Mn-Doped ZnO Nanosheets
Ahmed, Faheem,Kumar, Shalendra,Arshi, Nishat,Anwar, M. S.,Kim, Geun Woo,Heo, Si Nae,Byon, Eung Sun,Lee, Sung Hun,Lyu, Nam Jin,Koo, Bon Heun American Scientific Publishers 2012 Journal of Nanoscience and Nanotechnology Vol.12 No.7
<P>We report the synthesis of pure and Mn doped ZnO in the form of nanosheets using a simple and single step procedure involving a microwave assisted chemical method. As prepared Mn-doped ZnO nanosheets were characterized using X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), ultra violet-visible (UV-Vis), Raman spectroscopy and magnetization measurements. The structural studies using XRD and TEM revealed the absence of Mn-related secondary phases and showed that Mn-doped ZnO comprise a single phase nature with wurtzite structure. FESEM and TEM micrographs show that the average diameter of Mn-ZnO assembled nanosheets is about approximately 50 nm, and the length of a Mn-doped ZnO nanosheet building block which is made up of thin mutilayered sheets is around approximately 300 nm. Concerning the Raman scattering spectra, the shift in peak position of E2 (high) mode toward low frequencies due to the Mn doping could be explained well by means of the spatial correlation model. Magnetic measurements showed that Mn-doped ZnO nanosheets exhibit ferromagnetic ordering at or above room temperature.</P>
A Scalable Data Integrity Mechanism Based on Provable Data Possession and JARs
( Faheem Zafar ),( Abid Khan ),( Mansoor Ahmed ),( Majid Iqbal Khan ),( Farhana Jabeen ),( Zara Hamid ),( Naveed Ahmed ),( Faisal Bashir ) 한국인터넷정보학회 2016 KSII Transactions on Internet and Information Syst Vol.10 No.6
Cloud storage as a service provides high scalability and availability as per need of user, without large investment on infrastructure. However, data security risks, such as confidentiality, privacy, and integrity of the outsourced data are associated with the cloud-computing model. Over the year`s techniques such as, remote data checking (RDC), data integrity protection (DIP), provable data possession (PDP), proof of storage (POS), and proof of retrievability (POR) have been devised to frequently and securely check the integrity of outsourced data. In this paper, we improve the efficiency of PDP scheme, in terms of computation, storage, and communication cost for large data archives. By utilizing the capabilities of JAR and ZIP technology, the cost of searching the metadata in proof generation process is reduced from O(n) to O(1). Moreover, due to direct access to metadata, disk I/O cost is reduced and resulting in 50 to 60 time faster proof generation for large datasets. Furthermore, our proposed scheme achieved 50% reduction in storage size of data and respective metadata that result in providing storage and communication efficiency.