2,863 research outputs found
The quantum solvation, adiabatic versus nonadiabatic, and Markovian versus non-Markovian nature of electron transfer rate processes
In this work, we revisit the electron transfer rate theory, with particular
interests in the distinct quantum solvation effect, and the characterizations
of adiabatic/nonadiabatic and Markovian/non-Markovian rate processes. We first
present a full account for the quantum solvation effect on the electron
transfer in Debye solvents, addressed previously in J. Theore. & Comput. Chem.
{\bf 5}, 685 (2006). Distinct reaction mechanisms, including the quantum
solvation-induced transitions from barrier-crossing to tunneling, and from
barrierless to quantum barrier-crossing rate processes, are shown in the fast
modulation or low viscosity regime. This regime is also found in favor of
nonadiabatic rate processes. We further propose to use Kubo's motional
narrowing line shape function to describe the Markovian character of the
reaction. It is found that a non-Markovian rate process is most likely to occur
in a symmetric system in the fast modulation regime, where the electron
transfer is dominant by tunneling due to the Fermi resonance.Comment: 13 pages, 10 figures, submitted to J. Phys. Chem.
Interstitial Chemotherapy for Malignant Gliomas
Glioma is the most common primary tumor in the central nervous system (CNS). Even with aggressive treatments, gliomas remain as one of the most devastating tumors. Chemotherapy through oral administration of temozolomide (TMZ) is currently the standard regimen for malignant gliomas. However, the systemic toxicity and drug resistance are frequently observed in glioma patients. In order to improve the efficacy and minimize side effects, multiple strategies have been developed. Interstitial chemotherapy is a promising one. By directly delivering chemotherapeutic agents in tumor bed, interstitial chemotherapy bypasses the bloodâbrain barrier (BBB) and therefore achieves a higher concentration with less systemic exposure. In this chapter, we will have a thorough review on the development and the application of interstitial chemotherapy in gliomas, with the focus on the biomaterialâbased and convectionâenhanced delivery system. In addition, the future of interstitial chemotherapy is also be shortly discussed
Postoperative influences of the torsional phacoemulsification on foveal thickness and corneal edema
AIM: To report the influences onfoveal thickness and corneal edema after torsional phacoemulsification.<p>METHODS: Totally 52 patients(52 eyes)with age-related cataract were randomly assigned to phacoemulsification using torsional mode(26 eyes)or conventional ultrasound mode(26 eyes). The foveal thickness examined by optical coherence tomography(OCT)after surgery at 1, 4 and 12wk and corneal edema was examined by slit lamp after surgery at 1d.<p>RESULTS: The postoperative averagefoveal thickness datas of the two groups, comparing with corresponding preoperative datas, were significantly augmented at 1, 4 and 12wk(<i>P</i><0.05); the difference of foveal thickness was obviously augmented at 1wk postoperatively(<i>P</i><0.05), was no obvious differences at 4 and 12wk(<i>P</i>>0.05). The effects of corneal edema in torsional group were slighter(<i>P</i><0.05). <p>CONCLUSION: The postoperative influences onfoveal thickness and corneal edema with torsional mode are slighter than that with ultrasound mode, and the postoperative reactions with torsional mode are efficiently reduced
Effect of Gamma Irradiation on Microcrystalline Structure of Phragmites Cellulose
Effect of 60Co-Îł irradiation treatment on cellulose structure originating from Phragmites communis trim (PCT) was investigated on the basis of irradiation doses of 0 to 2000 kGy at a dose rate of 2 kGy h-1. Scanning electron micrograph images showed that surface morphologies of PCT cellulose could become fragmented after being treated with 60Co-Îł irradiation. Based on X-ray diffraction profiles, crystallinity and amorphous region of microcrystalline cellulose treated by irradiation were obviously changed. Fourier transform IR spectroscopy data indicated that a new characteristic peak corresponding to carbonyl (1734 cm -1) appeared after PCT cellulose was treated with 60Co-Îł irradiation, which suggested that PCT cellulose was degraded after irradiation treatment
Scaling in directed dynamical small-world networks with random responses
A dynamical model of small-world network, with directed links which describe
various correlations in social and natural phenomena, is presented. Random
responses of every site to the imput message are introduced to simulate real
systems. The interplay of these ingredients results in collective dynamical
evolution of a spin-like variable S(t) of the whole network. In the present
model, global average spreading length \langel L >_s and average spreading time
_s are found to scale as p^-\alpha ln N with different exponents.
Meanwhile, S behaves in a duple scaling form for N>>N^*: S ~ f(p^-\beta
q^\gamma t'_sc), where p and q are rewiring and external parameters, \alpha,
\beta, \gamma and f(t'_sc) are scaling exponents and universal functions,
respectively. Possible applications of the model are discussed.Comment: 4 pages, 6 Figure
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