Time filter

Source Type

Jeddah, Saudi Arabia

Zhai D.,Argonne National Laboratory | Wang H.-H.,Argonne National Laboratory | Yang J.,Argonne National Laboratory | Lau K.C.,Argonne National Laboratory | And 4 more authors.
Journal of the American Chemical Society | Year: 2013

In this paper we report on a kinetics study of the discharge process and its relationship to the charge overpotential in a Li-O2 cell for large surface area cathode material. The kinetics study reveals evidence for a first-order disproportionation reaction during discharge from an oxygen-rich Li2O2 component with superoxide-like character to a Li2O2 component. The oxygen-rich superoxide-like component has a much smaller potential during charge (3.2-3.5 V) than the Li 2O2 component (∼4.2 V). The formation of the superoxide-like component is likely due to the porosity of the activated carbon used in the Li-O2 cell cathode that provides a good environment for growth during discharge. The discharge product containing these two components is characterized by toroids, which are assemblies of nanoparticles. The morphologic growth and decomposition process of the toroids during the reversible discharge/charge process was observed by scanning electron microscopy and is consistent with the presence of the two components in the discharge product. The results of this study provide new insight into how growth conditions control the nature of discharge product, which can be used to achieve improved performance in Li-O2 cell. © 2013 American Chemical Society. Source

El Hadad S.,King Abdulazi University | Alakilli S.,King Abdulazi University | Rabah S.,King Abdulazi University | Sabir J.,King Abdulazi University
Biotechnology | Year: 2015

Hepatitis B virus (HBV) infection remains to be a worldwide health problem. In Saudi Arabia, HBV is the most predominant type of hepatitis followed by hepatitis C and hepatitis A while little is known about the molecular epidemiology of the prevalence of HBV genotype/subgenotype particularly in Jeddah. Serum samples were collected from HBV chronic patients and subjected to HBsAg gene amplification. Sequencing and phylogenetic analysis of the entire HBsAg gene sequences revealed that 11 isolates belonged to HBV/D while 4 isolates were associated with HBV/C. Interestingly, HBV/D subgenotypes identified eight HBV/D present isolates belonged to HBV/D1 while three isolates showed a new cluster supporting by a branch with 99% bootstrap value and 4.3-5.8% nucleotide divergence over the entire HBsAg gene from other known subgenotypes D1 to D10, despite they were appearing more related to HBV/D5. The three strains of the new D subgenotype showed unique amino acid sequences consisting of Thr7non, 75Pro in the preS1 gene, 112Ile, 161Gly in the preS2 gene and 196Glu, 197Ala, 238Ser, 259Cys in the S gene. In addition to three amino acid residues in the S gene (373Ile, 374Ala and 381Thr) were specified S118S isolate. Subsequently, it have been verified that HBV/D1 is the most prevalent HBV subgenotype in Jeddah as well as we proposed a novel subgenotype designated HBV/D11. The identification of HBV/D11 novel subgenotypes in the present study suggested that further studies with a large number of subjects in previously examined and unexamined areas may lead to discovering new HBV strain genotypes and/or subgenotypes circulating in Saudi Arabia. © 2015 Asian Network for Scientific Information. Source

Discover hidden collaborations