5 resultados para Lucilius, Gaius, ca. 180-ca. 102 B.C.

em Queensland University of Technology - ePrints Archive


Relevância:

100.00% 100.00%

Publicador:

Resumo:

Technological growth in the 21st century is exponential. Simultaneously, development of the associated risk, uncertainty and user acceptance are scattered. This required appropriate study to establish people accepting controversial technology (PACT). The Internet and services around it, such as World Wide Web, e-mail, instant messaging and social networking are increasingly becoming important in many aspects of our lives. Information related to medical and personal health sharing using the Internet is controversial and demand validity, usability and acceptance. Whilst literature suggest, Internet enhances patients and physicians’ positive interactions some studies establish opposite of such interaction in particular the associated risk. In recent years Internet has attracted considerable attention as a means to improve health and health care delivery. However, it is not clear how widespread the use of Internet for health care really is or what impact it has on health care utilisation. Estimated impact of Internet usage varies widely from the locations locally and globally. As a result, an estimate (or predication) of Internet use and their effects in Medical Informatics related decision-making is impractical. This open up research issues on validating and accepting Internet usage when designing and developing appropriate policy and processes activities for Medical Informatics, Health Informatics and/or e-Health related protocols. Access and/or availability of data on Internet usage for Medical Informatics related activities are unfeasible. This paper presents a trend analysis of the growth of Internet usage in medical informatics related activities. In order to perform the analysis, data was extracted from ERA (Excellence Research in Australia) ranked “A” and “A*” Journal publications and reports from the authenticated public domain. The study is limited to the analyses of Internet usage trends in United States, Italy, France and Japan. Projected trends and their influence to the field of medical informatics is reviewed and discussed. The study clearly indicates a trend of patients becoming active consumers of health information rather than passive recipients.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

The reactions of pyrrole and thiophene monomers in copper-exchanged mordenite have been investigated using EPR and UV–VIS absorption spectroscopy. The EPR spectra show a decrease in the intensity of the Cu2+ signal and the appearance of a radical signal due to the formation of oxidatively coupled oligomeric and/or polymeric species in the zeolite host. The reaction ceases when ca. 50% of the copper has reacted and differences in the form of the residual Cu2+ signal between the thiophene and pyrrole reactions suggest a greater degree of penetration of the reaction into the zeolite host for pyrrole, in agreement with previous XPS measurements. The EPR signal intensities show that the average length of the polymer chain that is associated with each radical centre is 15–20 and 5–7 monomer units for polypyrrole and polythiophene, respectively. The widths of the EPR signals suggest that these are at least partly due to small oligomers. The UV–VIS absorption spectra of the thiophene system show bands in three main regions: 2.8–3.0 eV (A), 2.3 eV (B) and 1.6–1.9 eV (D, E, F). Bands A and D–F occur in regions which have previously been observed for small oligomers, 4–6 monomer units in length. Band B is assigned to longer chain polythiophene molecules. We therefore conclude that the reaction between thiophene and copper-loaded mordenite produces a mixture of short oligomers together with some long chain polythiophene. The UV–VIS spectra of the pyrrole system show bands in the regions 3.6 eV (A), 2.7–3.0 eV (B, C) and 1.5–1.9 eV (D, F). Assignments of these bands are less certain than for the thiophene case because of the lack of literature data on the spectra of pyrrole oligomers.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

We have studied the carbonate mineral kamphaugite-(Y)(CaY(CO3)2(OH)·H2O), a mineral which contains yttrium and specific rare earth elements. Chemical analysis shows the presence of Ca, Y and C. Back scattering SEM appears to indicate a single pure phase. The vibrational spectroscopy of kamphaugite-(Y) was obtained using a combination of Raman and infrared spectroscopy. Two distinct Raman bands observed at 1078 and 1088cm(-1) provide evidence for the non-equivalence of the carbonate anion in the kamphaugite-(Y) structure. Such a concept is supported by the number of bands assigned to the carbonate antisymmetric stretching mode. Multiple bands in the ν4 region offers further support for the non-equivalence of carbonate anions in the structure. Vibrational spectroscopy enables aspects of the structure of the mineral kamphaugite-(Y) to be assessed.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

The use of hindered amine light stabilizers (HALS) to retard thermo- and photo-degradation of polymers has become increasingly common. Proposed mechanisms of polymer stabilisation involve significant changes to the HALS chemical structure; however, reports of the characterisation of these modified chemical species are limited. To better understand the fate of HALS and determine their in situ modifications, desorption electrospray ionisation mass spectrometry (DESI-MS) was employed to characterise ten commercially available HALS present in polyester-based coil coatings. TINUVIN® 770, 292, 144, 123, 152, and NOR371; HOSTAVIN® 3052, 3055, 3050, and 3058 were separately formulated with a pigmented, thermosetting polyester resin, cured on metal at 262 C and analysed directly by DESI-MS. High-level ab initio molecular orbital theory calculations were also undertaken to aid the mechanistic interpretation of the results. For HALS containing N-substituted piperidines (i.e., N-CH3, N-C(O)CH3, and N-OR) a secondary piperidine (N-H) analogue was detected in all cases. The formation of these intermediates can be explained either through hydrogen abstraction based mechanisms or direct N-OR homolysis with the former dominant under normal service temperatures (ca. 25-80 C), and the latter potentially becoming competitive under the high temperatures associated with curing (ca. 230-260 C). © 2013 Elsevier Ltd. All rights reserved.