Thermal stability analysis of organo-silicates, using solid phase microextraction techniques

An analysis of thermal degradation products evolved during the melt processing of organo-layered silicates (OLS) was carried out via the use of a solid phase microextraction (SPME) technique. Two commerical OLSs and one produced in-house were prepared for comparision. The solid phase microextraction technique proved to be a very effective technique for investigating the degradation of the OLS at a specific processing temperature. The results showed that most available OLSs will degrade under typical conditions required for the melt processing of many polymers, including thermoplastic polyurethanes. It is suggested that these degradation products may lead to changes in the structure and properties of the final polymer, particularly in thermoplastic polyurethanes, which seem significantly succeptable to the presence of these products. It is also suggested that many commercially available OLSs are produced in such a way that results in an excess of unbound organic modifier, giving rise to a greater quantity of degradation products. All OLSs where compared and characterised by TGA and GC-MS. (c) 2004 Elsevier B.V. All rights reserved.

The rural medicine rotation: Increasing rural recruitment through quality undergraduate rural experiences

TITLE: The Rural Medicine Rotation: Increasing Rural Recruitment through Quality Undergraduate Rural Experiences Eley Diann, University of Queensland, School of Medicine, Rural Clinical Division, Toowoomba 4350, Queensland Australia Baker Peter, University of Queensland, School of Medicine Rural, Clinical Division, Toowoomba 4350, Queensland Australia Chater Bruce, University of Queensland, Chair, Clinical School Management Committee, School of Medicine Rural Clinical Division, Queensland Australia CONTEXT: While rural background and rural exposure during medical training increases the likelihood of rural recruitment (Wilkinson, 2003), the quality and content of that exposure is the key to altering undergraduatesâ?? perceptions of rural practice. The Rural Clinical Division at University of Queensland (UQ) runs the Rural Medicine Rotation (RMR) within the School of Medicine. The RMR is one of five eight week clinical rotations in Year three and is compulsory for all students. The RMR provides the opportunity to learn from a wide range of health professionals and clinical exposure is not restricted to general practice but also includes remote area nursing, Indigenous health care, allied health professionals and medical specialists. Week 1 involves preparation for their rural placement with workshops and seminars and Week 8 consolidates their placement and includes case and project presentations and a summative assessment. Weeks 2-7 are spent living and working as part of the health team in different rural communities. SETTING: Rural communities in and around Queensland including locations such as Arnham Land, Thursday Island, Mt. Isa and Alice Springs METHOD: All aspects of the RMR are evaluated with surveys using both qualitative and quantitative free response questions, completed by all students at the end of the Week 8. RESULTS: Overall the RMR is evaluated highly and narratives offered by students show that the RMR provides a positive rural experience. The overall impact of the RMR for students in 2004 ranked 3.45 on a scale of 1 to 4 (1 = lowest and 4 = highest), and is exemplified by the following quote; â??I enjoyed my placement so much I am now considering rural medicine something I definitely had not considered beforeâ??. OUTCOME: The positive impact of the RMR on studentâ??s perceptions of rural medicine is encouraging and can help achieve the overall aim of increasing recruitment of the rural workforce in Australia.

Effects of glutathione, N-acetyl-cysteine, α-lipoic acid and dihydrolipoic acid on the cytotoxicity of a 2-pyridylcarboxamidrazone antimycobacterial agent in human mononuclear leucocytes in vitro

A series of antioxidants was used to explore the cytotoxicity of one particularly toxic antimycobacterial 2-pyridylcarboxamidrazone anti-tuberculosis agent against human mononuclear leucocytes (MNL), in comparison with isoniazid (INH) to aid future compound design. INH caused a significant reduction of nearly 40% in cell recovery compared with control (P < 0.0001), although the co-incubation with either glutathione (GSH, 1 mM) or (NAC, 1 mM) showed abolition of INH toxicity. In contrast, the addition of GSH or NAC 1 h after INH failed to protect the cells from INH toxicity (P < 0.0001). The 2-pyridyl-carboxamidrazone 'Compound 1' caused a 50% reduction in cell recovery compared with control (P < 0.001), although this was abolished by the presence of either GSH or NAC. A 1 h post incubation with either NAC or GSH after Compound 1 addition failed to protect the cells from toxicity (P < 0.001). Co-administration of lipoic acid (LA) abolished Compound 1-mediated toxicity, although again, this effect did not occur after LA addition 1 h post incubation with Compound 1 (P < 0.001). However, co-administration of dihydrolipoic acid (DHLA) prevented Compound 1-mediated cell death when incubated with the compound and also after 1 h of Compound 1 alone. Pre-treatment with GSH, then removal of the antioxidant resulted in abolition of Compound 1 toxicity (vehicle control, 63.6 ± 16.7 versus Compound 1 alone 26.1 ± 13.6% versus GSH pre-treatment, 65.7 ± 7.3%). In a cell-free incubation, NMR analysis revealed that GSH does not react with Compound 1, indicating that this agent is not likely to directly deplete membrane thiols. Compound 1's MNL toxicity is more likely to be linked with changes in cell membrane conformation, which may induce consequent thiol depletion that is reversible by exogenous thiols. © 2004 Elsevier B.V. All rights reserved.

Non-Gaussian error probability in optical soliton transmission

We find the probability distribution of the fluctuating parameters of a soliton propagating through a medium with additive noise. Our method is a modification of the instanton formalism (method of optimal fluctuation) based on a saddle-point approximation in the path integral. We first solve consistently a fundamental problem of soliton propagation within the framework of noisy nonlinear Schrödinger equation. We then consider model modifications due to in-line (filtering, amplitude and phase modulation) control. It is examined how control elements change the error probability in optical soliton transmission. Even though a weak noise is considered, we are interested here in probabilities of error-causing large fluctuations which are beyond perturbation theory. We describe in detail a new phenomenon of soliton collapse that occurs under the combined action of noise, filtering and amplitude modulation. © 2004 Elsevier B.V. All rights reserved.

Studies on the relative stabilities of Mn(II) and Mn(III) in complexes with N4O2 donor environments:crystal structures of [Mn(pybzhz)2] and [Mn(Ophsal)(imzH)2] ClO4 (pybzhz = N-(benzoyl)-N-(picolinylidene) hydrazine, Ophsal = N,N-o-phenylenebis(salicylideneimine), imzH = imidazole)

Five manganese complexes in an N 4O 2 donor environment have been prepared. Four of the compounds involve aroyl hydrazone as ligands and manganese is in a +2 oxidation state. The fifth compound was prepared using N,Nprime-o-phenylenebis(salicylideneimine) and imidazole as ligands where manganese is present in +3 oxidation state. X-ray crystal structure of one Mn +2 compound and the Mn +3 compound was determined. The relative stabilities of the Mn +2 and Mn +3 oxidation states were analyzed using the structural data and MO calculations. Manganese(II) complexes of four aroyl hydrazone ligands were prepared and characterized by different physicochemical techniques. The complexes are of the type Mn(L) 2, where L stands for the deprotonated hydrazone ligand. One of the compounds, Mn(pybzhz) 2, was also characterized by single crystal structure determination. In all these complexes, the Mn(II) is in an N 4O 2 donor environment and the Mn(II) center cannot be oxidized either chemically or electrochemically. However, when another ligand Ophsal is used to give the compound [Mn(Ophsal)(imzH) 2]ClO 4, which was also characterized by X-ray crystal structure determination, manganese can easily avail the +3 oxidation state. The relative stabilities of the +2 and +3 oxidation states of manganese were analyzed and it was concluded that the extent of distortion from the perfect octahedral geometry is the main controlling factor in these cases. © 2004 Elsevier B.V. All rights reserved.

Novel BCH code design for mitigation of phase noise induced cycle slips in DQPSK systems

We show that by proper code design, phase noise induced cycle slips causing an error floor can be mitigated for 28 Gbaud DQPSK systems. Performance of BCH codes are investigated in terms of required overhead. © 2014 OSA.

EU-funds efficiency and the first National Development Plan in Hungary 2004-2006

The author highlights the importance of the difference between the efficiency and effectiveness of using the EU-subsidies. If Hungary cannot use the financial means of the EU efficiently and effectively, then the goal of cohesion and convergence to the level of the old, developed countries of the EU, will be much more difficult and slower. The efficiency of the EU-subsidies involves a quantitative approach, where the ratio of the obliged and disposable amount of EU-subsidies can be measured. The effectiveness of EU-subsidies, on the other hand, requires a much more complicated and complex approach, than the efficiency. The effectiveness of the usage on a project level can be measured by the “added value” of the project; on program level it can be measured by the added GDP growth or employment. The article presents the results of research carried out in the Research Group of Professor Tibor Palánkai at Corvinus University of Budapest, Hungary.

A projektalapú szervezetek projektmarketing-tevékenységének sajátos kontextusa (Contextual features of project marketing activity of the project-based organisations)

Ez a tanulmány a projektvezetési szakirodalomban kialakult ismeretanyagot szem előtt tartva (noha tételesen nem hivatkozva arra) tárja fel azt a sajátos és tipikusnak nevezhető kontextust, amelyben a projektalapú szervezetek projektmarketing tevékenysége megnyilvánul. A tanulmány célja tehát nem magának a projektmarketingnek a kérdéskörére irányul, hanem elsősorban annak projektspecifikus kontextusára. Jellegét illetően a tanulmány spekulatív jellegű, vagyis lényegét tekintve nem empirikus kutatási eredményekből levont következtetésekre épül. _____ Traditional approach to project marketing focuses on process-related aspects of the marketing efforts of project- based organisations. This paper is different. Unlike to the traditional approach it highlights the decisive contextual features of project marketing, bearing in mind the typical project business from the point of view of project-based organisations. These features include: a) instead of physically existing products project-based organisations need to sell their ability to create the project outcome physically; b) the project outcome and the conditions of implementation are defined by the project client; c) project clients are involved in creating the project outcome; d) project implementation strategy applied in a client organisation may vary project by project. These determining contextual features shape to a great extent the actual competitive position of the project-based organisations which may vary project by project even in relation to the very same project client.

(Table 2) Radiocarbon ages of selected southern Baja California sediment cores

Piston, gravity, and multicores as well as hydrographic data were collected along the Pacific margin of Baja California to reconstruct past variations in the intensity of the oxygen-minimum zone (OMZ). Gravity cores collected from within the OMZ north of 24°N did not contain laminated surface sediments even though bottom water oxygen (BWO) concentrations were close to 5 µmol/kg. However, many of the cores collected south of 24°N did contain millimeter- to centimeter-scale, brown to black laminations in Holocene and older sediments but not in sediments deposited during the Last Glacial Maximum. In addition to the dark laminations, Holocene sediments in Soledad Basin, silled at 290 m, also contain white coccolith laminae that probably represent individual blooms. Two open margin cores from 430 and 700 m depth that were selected for detailed radiocarbon dating show distinct transitions from bioturbated glacial sediment to laminated Holocene sediment occurring at 12.9 and 11.5 ka, respectively. The transition is delayed and more gradual (11.3-10.0 ka) in another dated core from Soledad Basin. The observations indicate that bottom-water oxygen concentrations dropped below a threshold for the preservation of laminations at different times or that a synchronous hydrographic change left an asynchronous sedimentary imprint due to local factors. With the caveat that laminated sections should therefore not be correlated without independent age control, the pattern of older sequences of laminations along the North American western margin reported by this and previous studies suggests that multiple patterns of regional productivity and ventilation prevailed over the past 60 kyr.

(Table 2) Age determination of sediment cores from the continental shelf of Mac Roberston Land, East Antarctica

Geochemical records are presented for five sediment cores from basins on the continental shelf of Mac. Robertson Land, East Antarctica. The cores contain 2-4 m thick sequences of hemipelagic, siliceous mud and ooze (SMO) deposited under seasonally open marine conditions. The inner and middle shelf SMO sequences are massive dark olive green material, whereas the outer shelf SMO sequences are dark olive material interspersed with light olive green layers ~1-10 cm thick. The biogenic material is dominated by marine diatoms including Fragilariopsis curta, Fragilariopsis cylindrus, and Chaetoceros spp. in the dark-colored SMO and Corethron criophilum in the light-colored layers. Radiocarbon dates suggest that the cores provide continuous accumulation records extending from < 1 kyr before present (B.P.) back as far as 4-15 kyr B.P., with estimated accumulation rates of 0.07-5 mm/yr. The three core records from the middle and outer shelf suggest six episodes of increased accumulation of biogenic material at ~5.5 kyr B.P. (all three cores), 1, 2, and 6.2 kyr B.P. (two of the three cores), and 3.8 and 10.8 kyr B.P. (one core), most of which coincide with Corethron layers. We interpret these features as the result of enhanced diatom production over the outer shelf, possibly related to climatic warm periods. The absence of such features in the inner shelf core records is thought to reflect a relatively constant level of seasonal diatom production in adjacent waters maintained by a coastal polynya.

Variations in hip shape are associated with radiographic knee osteoarthritis : cross-sectional and longitudinal analyses of the Johnston County Osteoarthritis Project

Funding was provided in part by the US National Institute of Arthritis and Musculoskeletal and Skin Diseases (NIAMS) K23 AR061406 (Nelson); US National Institutes of Health (NIH)/NIAMS P60AR30701 (Jordan/Renner/Schwartz); US Centers for Disease Control/Association of Schools of Public Health S043 and S3486 (Jordan/Renner); K24-AR04884, P50-AR063043, and P50-AR060752 (Lane); and NIH/National Center for Advancing Translational Sciences KL2TR001109 (Golightly).

Variations in hip shape are associated with radiographic knee osteoarthritis : cross-sectional and longitudinal analyses of the Johnston County Osteoarthritis Project

Funding was provided in part by the US National Institute of Arthritis and Musculoskeletal and Skin Diseases (NIAMS) K23 AR061406 (Nelson); US National Institutes of Health (NIH)/NIAMS P60AR30701 (Jordan/Renner/Schwartz); US Centers for Disease Control/Association of Schools of Public Health S043 and S3486 (Jordan/Renner); K24-AR04884, P50-AR063043, and P50-AR060752 (Lane); and NIH/National Center for Advancing Translational Sciences KL2TR001109 (Golightly).

(Table 2) Stable carbon and oxygen isotope ratios of foraminifera of DSDP Holes 29-277 and 31-292

Oxygen isotopic studies both of benthic formanifera (Emiliani, 1954, doi:10.1126/science.119.3103.853; Savin et al., 1975, doi:10.1130/0016-7606(1975)86<1499:TMP>2.0.CO;2; Shackleton and Kennett, 1975, doi:10.2973/dsdp.proc.29.117.1975; Savin, 1977, doi:10.1146/annurev.ea.05.050177.001535) and shallow-marine carbonates ( Dorman, 1966; Devereux, 1967; Buchart, 1978, doi:10.1038/275121a0) have provided a useful monitor of marine palaeotemperatures. The Deep Sea Drilling Project (DSDP) has provided cores from many ocean basins to conduct detailed stable isotopic and palaeoceanographic studies of the Cenozoic and late Mesozoic. DSDP Sites 277 and 292, separated by ~60° latitude in Palaeogene times, each record an 18O enrichment in benthic foraminifera of nearly 1 per mil beginning at the Eocene-Oligocene boundary. Planktonic foraminiferal trends are similar to benthic trends in the high latitude southwest Pacific Ocean, but tropical planktonics show only a minor (~0.3 per mil) increase which may reflect a change in seawater composition. These results suggest a sudden cooling of Pacific deep waters and high latitude surface waters forms a useful stratigraphic marker for the Eocene-Oligocene boundary. This boundary is particularly important because of its association with several worldwide palaeo-oceanographic and biogeographic changes. These include a sudden drop in the calcite compensation depth of 1-2 km (van Andel et al., 1975; van Andel, 1975, doi:10.1016/0012-821X(75)90086-2); a decrease in planktonic microfossil diversity (Lipps, 1970, 10.2307/2406711; Kennett, 1978, doi:10.1016/0377-8398(78)90017-8; Sancetta, 1979, doi:10.1016/0377-8398(79)90025-2); a change in planktonic biogeographic patterns (Kennett, 1978, doi:10.1016/0377-8398(78)90017-8; Sancetta, 1979, doi:10.1016/0377-8398(79)90025-2; Haq and Lohmann, 1976, doi:10.1016/0377-8398(76)90008-6); and increased erosion of deep-sea sediments over wide areas (Kennet et al., 1972; Moore et al., 1978).