The objective of the present study is the synthesis of MWCNT-TiO2 hybrid nanostructures by solvothermal synthesis method with TiCl4 as precursor. The heat transfer enhancement due to the use of MWCNT-TiO2 nanofluid was investigated. As-prepared hybrid materials were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The results showed that MWCNTs were uniformly dec...

As a fluorescent isomer of adenine, 2-aminopurine (Ap) is a powerful probe of DNA dynamics and DNA-mediated charge transfer processes. Here, we report studies with femtosecond resolution of the excited-state dynamics of Ap in various solvents and in bimolecular complexes with nucleotides. Using time-resolved transient absorption and fluorescence up-conversion methods we identify charge transfer...

The role of short-range hydrogen bond interactions at the interface between electron transfer proteins cytochrome c(2) (cyt) and the reaction center (RC) from Rhodobacter sphaeroides was studied by mutation (to Ala) of RC residues Asn M187, Asn M188, and Gln L258 which form interprotein hydrogen bonds to cyt in the cyt-RC complex. The largest decrease in binding constant K(A) (8-fold) for a sin...

Arsenic is a widely distributed environmental toxin whose presence in drinking water poses a threat to >140 million people worldwide. The respiratory enzyme arsenite oxidase from various bacteria catalyses the oxidation of arsenite to arsenate and is being developed as a biosensor for arsenite. The arsenite oxidase from Rhizobium sp. str. NT-26 (a member of the Alphaproteobacteria) is a heterot...

The rate of electron transfer through multicomponent redox systems is often monitored by following the absorbance change due to the oxidation of the upstream pyridine nucleotide electron donor (NADPH or NADH) that initiates the process. Such coupled assay systems are powerful, but because of problems regarding the rate-limiting step, they sometimes limit the kinetic information that can be obta...

The kinetics of reduction and intracomplex electron transfer in electrostatically stabilized and covalently crosslinked complexes between ferredoxin-NADP+ reductase (FNR) and flavodoxin (Fld) from the cyanobacterium Anabuena PCC 7119 were compared using laser flash photolysis. The second-order rate constant for reduction by 5-deazariboflavin semiquinone (dRfII) of FNR within the electrostatical...

Electron transfer or quantum tunneling dynamics for excess or solvated electrons in dilute lithium-ammonia solutions have been studied by pulse electron paramagnetic resonance (EPR) spectroscopy at both X- (9.7 GHz) and W-band (94 GHz) frequencies. The electron spin-lattice (T(1)) and spin-spin (T(2)) relaxation data indicate an extremely fast transfer or quantum tunneling rate of the solvated ...

The heteroleptic series of Ru(bpY)n(dce)~:::n,with bpy = 2,2'-bipyridine, and dce = 4,4'diethoxycarbonyl-2,2'-bipyridine, has been investigated for the kinetic parameters of photo electron transfer, and for the magnetic field dependence of the net electron transfer efficiency (rIce) in photooxidations with methylviologen and propylviologen sulfonate (the latter only in the case n = 3) using ns-...

Electron-transfer processes through molecular systems have attracted much attention over the past fifty years. The traditional experimental approach for studying these processes is based on measuring the electron-transfer rate in D–B– A supramolecular systems between electron donor (D) and acceptor (A) units that are covalently linked through a molecular bridge (B). In the late 1990s, a combina...