50 research outputs found
Scaling Behavior of Cyclical Surface Growth
The scaling behavior of cyclical surface growth (e.g. deposition/desorption),
with the number of cycles n, is investigated. The roughness of surfaces grown
by two linear primary processes follows a scaling behavior with asymptotic
exponents inherited from the dominant process while the effective amplitudes
are determined by both. Relevant non-linear effects in the primary processes
may remain so or be rendered irrelevant. Numerical simulations for several
pairs of generic primary processes confirm these conclusions. Experimental
results for the surface roughness during cyclical electrodeposition/dissolution
of silver show a power-law dependence on n, consistent with the scaling
description.Comment: 2 figures adde
Does ohmic heating influence the flow field in thin-layer electrodeposition?
In thin-layer electrodeposition the dissipated electrical energy leads to a
substantial heating of the ion solution. We measured the resulting temperature
field by means of an infrared camera. The properties of the temperature field
correspond closely with the development of the concentration field. In
particular we find, that the thermal gradients at the electrodes act like a
weak additional driving force to the convection rolls driven by concentration
gradients.Comment: minor changes: correct estimation of concentration at the anode,
added Journal-re
Roughness Scaling in Cyclical Surface Growth
The scaling behavior of cyclical growth (e.g. cycles of alternating
deposition and desorption primary processes) is investigated theoretically and
probed experimentally. The scaling approach to kinetic roughening is
generalized to cyclical processes by substituting the time by the number of
cycles . The roughness is predicted to grow as where is
the cyclical growth exponent. The roughness saturates to a value which scales
with the system size as , where is the cyclical
roughness exponent. The relations between the cyclical exponents and the
corresponding exponents of the primary processes are studied. Exact relations
are found for cycles composed of primary linear processes. An approximate
renormalization group approach is introduced to analyze non-linear effects in
the primary processes. The analytical results are backed by extensive numerical
simulations of different pairs of primary processes, both linear and
non-linear. Experimentally, silver surfaces are grown by a cyclical process
composed of electrodeposition followed by 50% electrodissolution. The roughness
is found to increase as a power-law of , consistent with the scaling
behavior anticipated theoretically. Potential applications of cyclical scaling
include accelerated testing of rechargeable batteries, and improved
chemotherapeutic treatment of cancerous tumors
Naturally-Occurring Bioactives in Oral Cancer: Preclinical and Clinical Studies, Bottlenecks and Future Directions
Oral cancer (OC) is the eighth most common cancer, particularly prevalent in developing countries. Current treatment includes a multidisciplinary approach, involving chemo, radio, and immunotherapy and surgery, which depends on cancer stage and location. As a result of the side effects of currently available drugs, there has been an increasing interest in the search for naturally-occurring bioactives for treating all types of cancer, including OC. Thus, this comprehensive review aims to give a holistic view on OC incidence and impact, while highlights the preclinical and clinical studies related to the use of medicinal plants for OC prevention and the recent developments in bioactive synthetic analogs towards OC management. Chemoprophylactic therapies connect the use of natural and/or synthetic molecules to suppress, inhibit or revert the transformation of oral epithelial dysplasia (DOK) into oral squamous cell carcinoma (OSCC). Novel searches have underlined the promising role of plant extracts and phytochemical compounds, such as curcumin, green tea extract, resveratrol, isothiocyanates, lycopene or genistein against this malignancy. However, poor bioavailability and lack of in vivo and clinical studies and complex pharmacokinetic profiles limit their huge potential of application. However, recent nanotechnological and related advances have shown to be promising in improving the bioavailability, absorption and efficacy of such compounds.Scopu
The squares test as a measure of hand function in multiple sclerosis
Deterioration of hand function can be important in multiple sclerosis (MS). The standard way of assessing hand function in MS is the 9-hole peg test (9HPT), one of the three components of the MS functional composite measure. In this study we examine the squares test (ST), a test of hand function that is used extensively in handedness research. We evaluated reproducibility of the ST in 49 healthy controls, and both discriminatory power and concurrent validity of the ST in 38 MS patients and 18 age and gender matched controls. The ST proved to be a reliable and easy to administrate paper-and-pencil test of hand function. The ST showed a high and highly significant correlation with the standard 9HPT over a broad range of Expanded Disability Status Scale (EDSS) scores, and had high discriminatory power, also comparable to the 9HPT. Therefore, the ST is a candidate test for use in composite measures of MS related functional deficits for clinical practice and in clinical trials. (C) 2014 Elsevier B.V. All rights reserved