The Roles of Imaging Biomarkers in the Management of Chronic Neuropathic Pain

Chronic neuropathic pain (CNP) affects around 10% of the general population and has a significant social, emotional, and economic impact. Current diagnosis techniques rely mainly on patient-reported outcomes and symptoms, which leads to significant diagnostic heterogeneity and subsequent challenges in management and assessment of outcomes. As such, it is necessary to review the approach to a pathology that occurs so frequently, with such burdensome and complex implications. Recent research has shown that imaging methods can detect subtle neuroplastic changes in the central and peripheral nervous system, which can be correlated with neuropathic symptoms and may serve as potential markers. The aim of this paper is to review available imaging methods used for diagnosing and assessing therapeutic efficacy in CNP for both the preclinical and clinical setting. Of course, further research is required to standardize and improve detection accuracy, but available data indicate that imaging is a valuable tool that can impact the management of CNP.     

Synthesis of new chelating ion exchange resin with hydroxamic and amidoxime groups and study of its metal binding property

The synthesis of a new chelating ion exchanger with hydroxamic and amidoxime groups was performed by an aminolysis reaction of an ethylacrylate/acrylonitrile/divinylbenzene copolymer with hydroxylamine in the presence of sodium ethoxylate. We studied the retention property of the new resin for Pb(II), Cd(II), Cu(II), Ni(II), Zn(II), Mn(II), and Fe(III) metal cations from aqueous solutions. The retention capacity depends on the contact time, the pH of the solution, and the types of counterions of the metal cations. Competitive adsorptions of Pb(NO₃)₂ + Fe₂(SO₄)₃, Pb(NO₃)₂ + MnSO₄, Pb(NO₃)₂ + Cd(NO₃)₂, and Pb(NO₃)₂ + CuCl₂ on the new chelating ion exchanger were performed. The results showed that the resin preferentially retained the Pb(II) ions from the binary aqueous mixtures. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 88: 2956–2962, 2003     

Interchangeability with thresholds and degradation factors for Soft CSPs

Substitutability and interchangeability in constraint satisfaction problems (CSPs) have been used as a basis for search heuristics, solution adaptation and abstraction techniques. In this paper, we consider how the same concepts can be extended to soft constraint satisfaction problems (SCSPs). We introduce two notions: threshold α and degradation factor δ for substitutability and interchangeability, ( _α substitutability/interchangeability and ^δ substitutability/interchangeabi-lity respectively). We show that they satisfy analogous theorems to the ones already known for hard constraints. In _α interchangeability, values are interchangeable in any solution that is better than a threshold α, thus allowing to disregard differences among solutions that are not sufficiently good anyway. In ^δ interchangeability, values are interchangeable if their exchange could not degrade the solution by more than a factor of δ. We give efficient algorithms to compute ( ^δ / _α )interchangeable sets of values for a large class of SCSPs, and show an example of their application. Through experimental evaluation based on random generated problem we measure first, how often neighborhood interchangeable values are occurring, second, how well they can approximate fully interchangeable ones, and third, how efficient they are when used as preprocessing techniques for branch and bound search.     

Evaluation of the dielectric parameters from TSDC spectra: application to polymeric systems

The Thermally Stimulated Discharge Current (TSDC) technique is widely used for the study of main and secondary dielectric relaxations in polymers. The TSD current is described by different equations that can be arranged in a unique three-parameters (the activation energy W, A and B) general form. The physical meaning of A and B depends on the origin of the discharge currents. In this paper a method is proposed to obtain these parameters by fitting the experimental data with the analytical expression of the current, in the range around the maximum. Simulations were carried out to underline the relative importance of the parameters. A method is proposed for the decomposition of experimentally determined complex bands into a limited number of elementary peaks, each of them characterized by average values for W and B. The errors resulting from different approximations used in the analytical current expression or by the utilization of various expressions for the relaxation time are analyzed. The method is applied for the analy-sis of the TSDC spectra in the glass-rubber transition temperature regions of PET and PMMA, yielding several peaks characterized by narrow distributions of W (ΔW≈± 0.06 eV). Received: 18 September 2000 / Reviewed and accepted: 20 September 2000     

Charge injection/extraction at a metal-dielectric interface: experimental validation - [feature article]

Electron injection from a silver cathode into a polyethylene terephthalate film, and electron extraction at the anode, have been experimentally demonstrated. There is no experimental evidence of a threshold electric field for injection or extraction.     

Sorption equilibrium of Cr(VI) ions by strong base anion exchangers with pyridine structures

Chromate sorption on pyridine strong base anion exchangers with different functional groups (methyl, ethyl, and butyl groups), at the quaternary nitrogen atoms, was studied as a function of various initial concentrations (100–1500 mg Cr/L) and counterion type. The studied resins in the Cl^?[ form have higher Cr(VI)‐retention capacities than those in the SO form. The pyridine strong base anion exchangers showed a selectivity reversal for the sulfate and chromate anions compared to that of the commercial resins. The alkyl substituent length of the quaternary nitrogen atoms exerted a substantial influence on the Cr(VI)‐retention capacity values for the resins in the Cl^? form; the chromate anions preferred resins with methyl functional groups, that is, resins with a greater hydrophilic structure. For the resins in the SO form the length of the substituent at the quaternary nitrogen atom had only a negligible influence on their Cr(VI)‐retention values. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 93: 1957–1963, 2004     

Space charge studies in LDPE using combined isothermal and nonisothermal current measurements

Using a recently developed procedure combining isothermal and nonisothermal current measurements space charge trapping and transport in LDPE was successfully studied. Unaged, thermally and electrically aged samples were investigated. The samples were conditioned before each measurement in order to obtain reproducible results. In the nonisothermal measurements appeared a broad peak (40/spl deg/C to 50/spl deg/C) that was possible to decompose into two or three peaks (35, 45 and 65/spl deg/C). At even higher temperature another peak was sometimes present (85/spl deg/C) depending on the prior sample conditioning. The space charge is trapped near the surface in deep traps (maximum depth of /spl ap/15 /spl mu/m). Relaxation times, mobilities and activation energies have been calculated for different charging/discharging conditions. For unaged samples the reproducibility of the results was poor while for the aged polyethylene it was quite good, meaning that aging helps conditioning. In the electrically aged LDPE there is a decrease of conductivity and the broad peak of the nonisothermal spectra shows a slight shift towards higher temperatures when compared with the data found in the thermally aged polymer.     

A Dedicated On-Board Dual-Energy Computer Tomograph

A dedicated on-board dual energy computer tomograph able to generate both tomographic and digital radiographic images of unconsolidated sediments cores with a diameter up to 12 cm and a height up to 1 m was built and tested on-board of the R/V Mare Nigrum. This instrument, designed to be used on-board of any oceanographic research vessel with minimum adaptations, can work very well on stationary laboratory too, provided that there is adequate protection against hard X-rays. The tomograph has a single 160 kV X-ray tube and two set of 240 in-line X-ray detectors separated by a copper attenuator (dual-energy arrangement) allowing one to obtain tomographic as well as digital radiographic images depicting the distribution of both density and effective atomic number of the objects. In tomographic and radiographic mode, the spatial resolution of reconstructed images of the linear attenuation coefficient is about 0.5 mm while in dual-energy mode, when reconstructed images depict the distribution of densities and effective atomic numbers that requires an additional smoothing filtering, the spatial resolution is about 1 mm.