Effect of preparation technique on the properties of Mo-containing Al-MCM-41

The Al-MCM-41 has been used as support to prepare Mo-containing catalysts. The 12- molybdophosphoric heteropoly acid (HPMo) is used as initial compound. The catalysts are synthesized by two different methods: incipient impregnation with aqueous solution of the acid and mechanochemical synthesis. The samples were tested in the reaction of the thiophene hydrodesulfurization after activation with mixture H₂ + H₂S. The effect of the preparation method of the catalysts on their physicochemical and catalytic properties has been studied. A partial destruction of the loaded compound is observed in mechanochemically treated sample whereas the aggregates are formed from the particles of different size in the impregnated sample. The specific surface area of the sample prepared by mechanical–chemical treatment decreases 2–3 times, while the total pore volume is about four times lower. The HDS activity is higher on the impregnated sample than on the mechanochemically treated one.     

High yield formation of carbon nanotubes using a rotating cathode in open air

Carbon nanotubes (CNTs) have been synthesized using the arc discharge method with a rotating graphite disc as the cathode. Arcing was carried out in open air and without the use of catalysts. The current density was maintained constant through out the experiment, while, the rate of rotation of the cathode and atmosphere under which arcing was carried out were changed during experimentation. Characterization of the samples produced indicates that rotation of the cathode has a significant impact on the quality and yield of the process. It is proposed that rotation of the cathode drags plasma formed between two electrodes away from high temperature region. This results in a sudden quenching of the reactive plasma. The time available for nucleation and growth phenomena is significantly reduced and thus leads to the formation of highly graphitic multi walled CNTs (yield 60%) and traces of double walled CNTs.     

Least privilege and more [computer security]

With new methods for enforcing security policies comes the opportunity to formulate application-specific policies. But leveraging that flexibility might prove a difficult problem, not only in practice, but also in theory.     

Technology Scapegoats and Policy Saviors

IEEE Security & Privacy's associate editor in chief discusses technology's role in identity fraud and identity theft.     

Periodontal management of gingival overgrowth in the heart transplant patient: a case report

Heart transplant patients take several medications that could affect their periodontal health. Gingival overgrowth associated with cyclosporin (immunosuppressant agent) and nifedipine (calcium channel blocker) is well documented. Candidal infections often develop because of immune suppression. This report describes the clinical and histopathological changes in the gingival tissues of a heart transplant patient and their management. The gingival tissues exhibited pronounced enlargement. The gingivae were lobulated, and the surface of the lobulations was pebbly and granular. Biopsies showed lobules of fibrous connective tissue covered by stratified squamous epithelium. The outer surfaces were dotted with numerous smaller papillations. Candidal hyphae were present in the superficial layers of the epithelium. The extensive papillary lesions appear to be related to candidiasis and constitute a condition which is best designated as papillary stomatitis. Hyperplastic gingival tissues were excised, and the patient was placed on periodic maintenance. One-year postoperative follow-up showed minor gingival growth.     

Characterization of the epidermal growth factor receptor in pig oviduct and endometrium

Two different plaque variants of Japanese encephalitis virus were selected from a wild-type Taiwanese isolate using Vero cells. One variant was found to exhibit small plaque morphology with retarded virus replication kinetics in Vero cells, and was demonstrated to be resistant to monoclonal antibody (mAb) E3.3 neutralization. The other variant showed large plaque morphology, was sensitive to mAb E3.3 neutralization, and manifested reduced virulence in mice on both intracranial and intraperitoneal inoculations. These two variants propagated in Vero cells retained high levels of infectivity but had relatively low HA titers as compared with the parent strain. The envelope sequences of these two variants showed four amino acid differences at residues E-85 (Glu/Arg), E-306 (Glu/Gly), E-331 (Ser/Arg), and E-387 (Met/Arg). Our results indicated the neutralizing epitope of Japanese encephalitis virus did not overlap with virus virulence determinant.     

Wall-bounded laminar sink flows

Summary The laminar flow near an infinite plane wall perpendicular to a line sink of constant strength is investigated in the limit of large Reynolds numbers. Self-similarity requires that fluid is issuing from the boundary layer. The inviscid flow outside the boundary layer is governed by the Euler equations. A one-parametric set of solutions to the Euler equations with appropriate boundary conditions is given. Uniqueness of the inviscid flow solution is obtained from matching with the boundary layer expansion. The solution of the boundary-layer equations is given both in closed form and numerically. It is found that at the edge of the boundary layer the vorticity decays algebraically.Dedicated to Prof. Dr. Dr. h. c. Franz Ziegler on the occasion of his 60th birthday