Analysis of Compact Fluorescent Lights for Use by Patients with Photosensitive Conditions

Ultraviolet radiation (UVR) is hazardous to patients with photosensitive skin disorders, such as lupus erythematosus, xeroderma pigmentosum and skin cancer. As such, these patients are advised to minimize their exposure to UVR. Classically, this is accomplished through careful avoidance of sun exposure and artificial tanning booths. Indoor light bulbs, however, are generally not considered to pose significant UVR hazard. We sought to test this notion by measuring the UV emissions of 19 different compact fluorescent light bulbs. The ability to induce skin damage was assessed with the CIE erythema action spectrum, ANSI S(λ) generalized UV hazard spectrum and the CIE photocarcinogenesis action spectrum. The results indicate that there is a great deal of variation amongst different bulbs, even within the same class. Although the irradiance of any given bulb is low, the possible daily exposure time is rather lengthy. This results in potential daily UVR doses ranging from 0.1 to 625 mJ cm⁻², including a daily UVB (290–320 nm) dose of 0.01 to 15 mJ cm⁻². Because patients are exposed continually over long time frames, this could lead to significant cumulative damage. It would therefore be prudent for patients to use bulbs with the lowest UV irradiance.     

Preparation of activated carbon from date pits: Effect of the activation agent and liquid phase oxidation

Two series of activated carbons have been prepared from date pits; series C, using carbon dioxide as activating agent, and series S, prepared by activation with steam under the same experimental conditions. The obtained samples were oxidized with nitric acid in order to introduce more oxygen surface groups. The surface area and porosity of the parent and oxidized activated carbons were studied by N₂ adsorption at 77 K and CO₂ adsorption at 273 K. The oxygen surface complexes were characterized by temperature-programmed decomposition (TPD). The results show that carbon dioxide and steam activations produce microporous carbons with an increasing amount of CO evolving groups when increasing the burn-off. On the other hand, oxidation with nitric acid increases the amount of CO and CO₂ evolved by the decomposition of surface oxygen groups, this increase being related to the development of porosity in the carbon with the degree of activation and to the activating agent used (CO₂ versus steam).     

Determination of the size and composition of multicomponent ethanol/water droplets by cavity-enhanced Raman scattering

Cavity-enhanced Raman scattering is used to determine the size and composition of multicomponent ethanol/water droplets in the concentration range 7.5–19% ethanol by volume. Under the experimental conditions presented here, the integrated CERS signal from ethanol shows an exponential increase with increase in ethanol concentration when compared with the integrated intensity of the water band. The calibration is shown to be invariant with particle size over the droplet radius range 20–35 μm. In addition to providing a method for determining particle size and composition, initial studies show that the evaporation dynamics of these multicomponent droplets can be probed by CERS.     

Development,validation, and implementation of capillary gel electrophoresis as a replacement for SDS‐PAGE for purity analysis of IgG2 mAbs

Capillary gel electrophoresis (CGE) methods with UV detection were developed for reduced and non‐reduced mAb analysis. These methods can be used to evaluate mAb purity, offering more reproducible quantitation compared with that of traditional SDS‐PAGE methods. These CGE methods have been utilized as platform technology for bioprocess development, formulation development, mAb characterization, drug substance/drug product release testing as well as a required methodology for stability testing. We have found these CGE methods to be applicable across a platform of mAbs in preclinical and clinical development, with the majority of mAbs requiring no modification to the method conditions. This methodology has been ICH validated and transferred to several supporting organizations. The data presented herein describes the development of CGE methodology, platform application to mAb purity analysis, ICH validation, reliability metrics, and considerations on technology enhancement for improved performance and throughput.     

Cobalt(iii) complexes as functional ligands for metal (oxide) surfaces

Co(iii) polyamine complexes with either two or three labile coordination sites bind strongly to high surface area metal oxides such as goethite or aluminium trihydroxide, and have been shown to act as passivating agents for aluminium flake in aqueous media, in addition to providing a potential method for surface functionalisation.     

Syntheses and excitation transfer studies of near-orthogonal free-base porphyrin-ruthenium phthalocyanine dyads and pentad

A new series of molecular dyads and pentad featuring free-base porphyrin and ruthenium phthalocyanine have been synthesized and characterized. The synthetic strategy involved reacting free-base porphyrin functionalized with one or four entities of phenylimidazole at the meso position of the porphyrin ring with ruthenium carbonyl phthalocyanine followed by chromatographic separation and purification of the products. Excitation transfer in these donor-acceptor polyads (dyad and pentad) is investigated in nonpolar toluene and polar benzonitrile solvents using both steady-state and time-resolved emission techniques. Electrochemical and computational studies suggested that the photoinduced electron transfer is a thermodynamically unfavorable process in nonpolar media but may take place in a polar environment. Selective excitation of the donor, free-base porphyrin entity, resulted in efficient excitation transfer to the acceptor, ruthenium phthalocyanine, and the position of imidazole linkage on the free-base porphyrin could be used to tune the rates of excitation transfer. The singlet excited Ru phthalocyanine thus formed instantly relaxed to the triplet state via intersystem crossing prior to returning to the ground state. Kinetics of energy transfer (k(ENT)) was monitored by performing transient absorption and emission measurements using pump-probe and up-conversion techniques in toluene, respectively, and modeled using a F?rster-type energy transfer mechanism. Such studies revealed the experimental k(ENT) values on the order of 10(10)-10(11) s(-1), which readily agreed with the theoretically estimated values. Interestingly, in polar benzonitrile solvent, additional charge transfer interactions in the case of dyads but not in the case of pentad, presumably due to the geometry/orientation consideration, were observed.     

Comparison of the Efficiency of the One and Two-Step Process for the Production of BSCCO (2212) Powders by Means of Analytical Techniques

 The efficiency of the production of the high temperature superconducting powders Bi₂Sr₂CaCu₂O_8+x (BSCCO 2212) using the solid state reaction in one or two step processes under different thermal treatment was compared by means of different modern analytical techniques. Through the same techniques the optimization of the production of the production of Bi-2212 powder produced by the two step process, was achieved. X-ray diffraction analysis (XRD) and Raman spectroscopy were used to characterize the products for their stoichiometry and phase-purity. The grain size of the powders was observed by scanning electron microscopy (SEM), while their superconducting properties were tested by electrical DC-resistivity and magnetic susceptibility measurements using a superconducting quantum interference device (SQUID). It resulted that the two step process gives a high quality BSCCO 2212 superconducting powder with T _c = 85 K, in a shorter time and with a greater recovery rate than the one step process. Received May 3, 1999. Revision April 27, 2000.