955 resultados para Gear selectivity


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Composite membranes with mordenite (MOR) incorporated in poly vinyl alcohol (PVA)–polystyrene sulfonic acid (PSSA) blend tailored with varying degree of sulfonation are reported. Such a membrane comprises a dispersed phase of mordenite and a continuous phase of the polymer that help tuning the flow of methanol and water across it. The membranes on prolonged testing in a direct methanol fuel cell (DMFC) exhibit mitigated methanol cross-over from anode to the cathode. The membranes have been tested for their sorption behaviour, ion-exchange capacity, electrochemical selectivity and mechanical strength as also characterized by Fourier transform infrared spectroscopy and thermogravimetric analysis. Water release kinetics has been measured by magnetic resonance imaging (NMR imaging) and is found to be in agreement with the sorption data. Similarly, methanol release kinetics studied by volume-localized NMR spectroscopy (point resolved spectroscopy, PRESS) clearly demonstrates that the dispersion of mordenite in PVA–PSSA retards the methanol release kinetics considerably. A peak power-density of 74 mW/cm2 is achieved for the DMFC using a PVA–PSSA membrane electrolyte with 50% degree of sulfonation and 10 wt.% dispersed mordenite phase. A methanol cross-over current as low as 7.5 mA/cm2 with 2 M methanol feed at the DMFC anode is observed while using the optimized composite membrane as electrolyte in the DMFC, which is about 60% and 46% lower than Nafion-117 and PVA–PSSA membranes, respectively, when tested under identical conditions.

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Gene therapy is a promising novel approach for treating cancers resistant to or escaping currently available modalities. Treatment approaches are based on taking advantage of molecular differences between normal and tumor cells. Various strategies are currently in clinical development with adenoviruses as the most popular vehicle. Recent developments include improving targeting strategies for gene delivery to tumor cells with tumor specific promoters or infectivity enhancement. A rapidly developing field is as well replication competent agents, which allow improved tumor penetration and local amplification of the anti-tumor effect. Adenoviral cancer gene therapy approaches lack cross-resistance with other treatment options and therefore synergistic effects are possible. This study focused on development of adenoviral vectors suitable for treatment of various gynecologic cancer types, describing the development of the field from non-replicating adenoviral vectors to multiple-modified conditional replicating viruses. Transcriptional targeting of gynecologic cancer cells by the use of the promoter of vascular endothelial growth factor receptor type 1 (flt-1) was evaluated. Flt-1 is not expressed in the liver and thus an ideal promoter for transcriptional targeting of adenoviruses. Our studies implied that the flt-1 promoter is active in teratocarcinomas.and therefore a good candidate for development of oncolytic adenoviruses for treatment of this often problematic disease with then poor outcome. A tropism modified conditionally replicating adenovirus (CRAd), Ad5-Δ24RGD, was studied in gynecologic cancers. Ad5-Δ24RGD is an adenovirus selectively replication competent in cells defective in the p16/Rb pathway, including many or most tumor cells. The fiber of Ad5-Δ24RGD contains an integrin binding arginine-glycine-aspartic acid motif (RGD-4C), allowing coxackie-adenovirus receptor independent infection of cancer cells. This approach is attractive because expression levels of CAR are highly variable and often low on primary gynecological cancer cells. Oncolysis could be shown for a wide variety of ovarian and cervical cancer cell lines as well as primary ovarian cancer cell spheroids, a novel system developed for in vitro analysis of CRAds on primary tumor substrates. Biodistribution was evaluated and preclinical safety data was obtained by demonstrating lack of replication in human peripheral blood mononuclear cells. The efficicacy of Ad5-Δ24RGD was shown in different orthotopic murine models including a highly aggressive intraperitoneal model of disseminated ovarian cancer cells, where Ad5-Δ24RGD resulted in complete eradication of intraperitoneal disease in half of the mice. To further improve the selectivity and specificity of CRAds, triple-targeted oncolytic adenoviruses were cloned, featuring the cyclo-oxygenase-2 (cox-2) promoter, E1A transcomplementation and serotype chimerism. Those viruses were evaluated on ovarian cancer cells for specificity and oncolytic potency with regard to two different cox2 versions and three different variants of E1A (wild type, delta24 and delta2delta24). Ad5/3cox2Ld24 emerged as the best combination due to enhanced selectivity without potency lost in vitro or in an aggressive intraperitoneal orthotopic ovarian tumor model. In summary, the preclinical therapeutic efficacy of the CRAds tested in this study, taken together with promising biodistribution and safety data, suggest that these CRAds are interesting candidates for translation into clinical trials for gynecologic cancer.

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The photochemistry and photophysics of organic molecules in organized assemblies are being studied with great interest in order to understand the features controlling the selectivity in the photoreactions brought about by these media.l These studies have paved the way to an intriguing number of possibilities by which photoreactivity can be modified. In this connection, we have investigated the photobehavior of a number of phenyl alkyl ketones and cu,cu-dimethylphenyl alkyl ketones (Scheme I) incorporated in the hydrophobic interior of cyclodextrin cavities.

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Objective 1. Measure spatial and temporal trawl frequency of scallop grounds using VMS data. This will provide a relative measure of how often individual undersized scallops are caught and put through a tumbler 2. Estimate discard mortality and growth rates for saucer scallops using cage experiments. 3. Evaluate the current management measures, in particular the seasonal closure, rotational closure and seasonally varying minimum legal sizes using stock assessment and management modeling models. Recommend optimal range of management measures to ensure long-term viability and value of the Scallop fishery based on a formal management strategy evaluation. Outcomes acheived to date: 1. Improved understanding of the survival rates of discarded sub-legal scallops; 2. Preliminary von Bertalanffy growth parameters using data from tagged-and-released scallops; 3. Changing trends in vessels and fishing gear used in the Queensland scallop fishery and their effect on scallop catch rates over time using standardised catch rates quantified; 4. Increases in fishing power of vessels operating in the Queensland scallop fishery quantified; 5. Trawl intensity mapped and quantified for all Scallop Replenishment Areas; 6. Harvest Strategy Evaluations completed.

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Standardised time series of fishery catch rates require collations of fishing power data on vessel characteristics. Linear mixed models were used to quantify fishing power trends and study the effect of missing data encountered when relying on commercial logbooks. For this, Australian eastern king prawn (Melicertus plebejus) harvests were analysed with historical (from vessel surveys) and current (from commercial logbooks) vessel data. Between 1989 and 2010, fishing power increased up to 76%. To date, both forward-filling and, alternatively, omitting records with missing vessel information from commercial logbooks produce broadly similar fishing power increases and standardised catch rates, due to the strong influence of years with complete vessel data (16 out of 23 years of data). However, if gaps in vessel information had not originated randomly and skippers from the most efficient vessels were the most diligent at filling in logbooks, considerable errors would be introduced. Also, the buffering effect of complete years would be short lived as years with missing data accumulate. Given ongoing changes in fleet profile with high-catching vessels fishing proportionately more of the fleet’s effort, compliance with logbook completion, or alternatively ongoing vessel gear surveys, is required for generating accurate estimates of fishing power and standardised catch rates.

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Adenoviral gene therapy is an experimental approach to cancer refractory to standard cancer therapies. Adenoviruses can be utilized as vectors to deliver therapeutic transgenes into cancer cells, while gene therapy with oncolytic adenoviruses exploits the lytic potential of viruses to kill tumor cells. Although adenoviruses demonstrate several advantages over other vectors - such as the unparalleled transduction efficacy and natural tropism to a wide range of tissues - the gene transfer efficacy to cancer cells has been limited, consequently restricting the therapeutic effect. There are, however, several approaches to circumvent this problem. We utilized different modified adenoviruses to obtain information on adenovirus tropism towards non-small cell lung cancer (NSCLC) cells. To enhance therapeutic outcome, oncolytic adenoviruses were evaluated. Further, to enhance gene delivery to tumors, we used mesenchymal stem cells (MSCs) as carriers. To improve adenovirus specificity, we investigated whether widely used cyclooxygenase 2 (Cox-2) promoter is induced by adenovirus infection in nontarget cells and whether selectivity can be retained by the 3 untranslated region (UTR) AU-rich elements. In addition, we investigated whether switching adenovirus fiber can retain gene delivery in the presence of neutralizing antibodies. Our results show that adenoviruses, whose capsids were modified with arginine-glycine-aspartatic acid (RGD-4C), the serotype 3 knob, or polylysins displayed enhanced gene transfer into NSCLC cell lines and fresh clinical specimens from patients. The therapeutic efficacy was further improved by using respective oncolytic adenoviruses with isogenic 24bp deletion in the E1A gene. Cox-2 promoter was also shown to be induced in normal and tumor cells following adenovirus infection, but utilization of 3 UTR elements can increase the tumor specificity of the promoter. Further, the results suggested that use of MSCs could enhance the bioavailability and delivery of adenoviruses into human tumors, although cells had no tumor tropism per se. Finally, we demonstrated that changing adenovirus fiber can allow virus to escape from existing neutralizing antibodies when delivered systemically. In conclusion, these results reveal that adenovirus gene transfer and specificity can be increased by using modified adenoviruses and MSCs as carriers, and fiber modifications simultaneously decrease the effect of neutralizing antibodies. This promising data suggest that these approaches could translate into clinical testing in patients with NSCLC refractory to current modalities.

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Vascular intimal hyperplasia is a major complication following angioplasty. The hallmark feature of this disorder is accumulation of dedifferentiated smooth muscle cells (SMCs) to the luminal side of the injured artery, cellular proliferation, migration, and synthesis of extracellular matrix. This finally results in intimal hyperplasia, which is currently considered an untreatable condition. According to current knowledge, a major part of neointimal cells derive from circulating precursor cells. This has outdated the traditional in vitro cell culture methods of studying neointimal cell migration and proliferation using cultured medial SMCs. Somatostatin and some of its analogs with different selectivity for the five somatostatin receptors (sst1 through sst5) have been shown to have vasculoprotective properties in animal studies. However, clinical trials using analogs selective for sst2/sst3/sst5 to prevent restenosis after percutaneous transluminal coronary angioplasty (PTCA) have failed to show any major benefits. Sirolimus is a cell cycle inhibitor that has been suggested to act synergistically with the protein-tyrosine kinase inhibitor imatinib to inhibit intimal hyperplasia in rat already at well-tolerated submaximal oral doses. The mechanisms behind this synergy and its long-term efficacy are not known. The aim of this study was to set up an ex vivo vascular explant culture model to measure neointimal cell activity without excluding the participation of circulating progenitor cells. Furthermore, two novel potential vasculoprotective treatment strategies were evaluated in detail in rat models of intimal hyperplasia and in the ex vivo explant model: sst1/sst4-selective somatostatin receptor analogs and combination treatment with sirolimus and imatinib. This study shows how whole vessel explants can be used to study the kinetics of neointimal cells and their progenitors, and to evaluate the anti-migratory and anti-proliferative properties of potential vasculoprotective compounds. It also shows how the influx of neointimal progenitor cells occurs already during the first days after vascular injury, how the contribution of cell migration is more important in the injury response than cell proliferation, and how the adventitia actively contribute in vascular repair. The vasculoprotective effect of somatostatin is mediated preferentially through sst4, and through inhibition of cell migration rather than of proliferation, which may explain why sst2/sst3/sst5-selective analogs have failed in clinical trials. Furthermore, a brief early oral treatment with the combination of sirolimus and imatinib at submaximal doses results in long-term synergistic suppression of intimal hyperplasia. The synergy is a result of inhibition of post-operative thrombocytosis and leukocytosis, inhibition of neointimal cell migration to the injury-site, and maintenance of cell integrity by inhibition of apoptosis and SMC dedifferentiation. In conclusion, the influx of progenitor cells already during the first days after injury and the high neointimal cell migratory activity underlines the importance of early therapeutic intervention with anti-migratory compounds to prevent neointimal hyperplasia. Sst4-selective analogs and the combination therapy with sirolimus and imatinib represent potential targets for the development of such vasculoprotective therapies.

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Gas discharge plasmas formed at atmospheric pressure and near room temperature have recently been shown as a promising tool for cancer treatment. The mechanism of the plasma action is attributed to generation of reactive oxygen and nitrogen species, electric fields, charges, and photons. The relative importance of different modes of action of atmospheric-pressure plasmas depends on the process parameters and specific treatment objects. Hence, an in-depth understanding of biological mechanisms that underpin plasma-induced death in cancer cells is required to optimise plasma processing conditions. Here, the intracellular factors involved in the observed anti-cancer activity in melanoma Mel007 cells are studied, focusing on the effect of the plasma treatment dose on the expression of tumour suppressor protein TP73. Over-expression of TP73 causes cell growth arrest and/or apoptosis, and hence can potentially be targeted to enhance killing efficacy and selectivity of the plasma treatment. It is shown that the plasma treatment induces dose-dependent up-regulation of TP73 gene expression, resulting in significantly elevated levels of TP73 RNA and protein in plasma-treated melanoma cells. Silencing of TP73 expression by means of RNA interference inhibited the anticancer effects of the plasma, similar to the effect of caspase inhibitor z-VAD or ROS scavenger N-acetyl cysteine. These results confirm the role of TP73 protein in dose-dependent regulation of anticancer activity of atmospheric-pressure plasmas.

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This study was initiated in response to a scarcity of data on the efficiency, selectivity and discard mortality of baited traps to target Scylla serrata. Five replicates of four traps, including "hoop nets", rigid "wire pots", and collapsible "round" and "rectangular" pots were deployed for 3, 6 and 24 h in two Australian estuaries. Trapped S. serrata were "discarded" into cages and monitored with controls over 3 d. All S. serrata were assessed for damage, while subsets of immediately caught and monitored individuals had haemolymph constituents quantified as stress indices. All traps retained similar-sized (8.119.1 cm carapace width) S. serrata, with catches positively correlated to deployment duration. Round pots were the most efficient for S. serrata and fishmostly Acanthopagrus australis (3 mortality). Hoop nets were the least efficient and were often damaged. No S. serrata died, but 18 were wounded (biased towards hoop nets), typically involving a missing swimmeret. Physiological responses were mild and mostly affected by biological factors. The results validate discarding unwanted S. serrata for controlling exploitation, but larger mesh sizes or escape vents in pots and restrictions on hoop nets would minimise unnecessary catches, pollution and ghost fishing. © 2012 International Council for the Exploration of the Sea. Published by Oxford University Press. All rights reserved.

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Suitable long term species-specific catch rate and biological data are seldom available for large shark species, particularly where historical commercial logbook reporting has been poor. However, shark control programs can provide suitable data from gear that consistently fishes nearshore waters all year round. We present an analysis of the distribution of 4757 . Galeocerdo cuvier caught in surface nets and on drumlines across 9 of the 10 locations of the Queensland Shark Control Program (QSCP) between 1993 and 2010. Standardised catch rates showed a significant decline (p<. 0.0001) in southern Queensland locations for both gear types, which contrasts with studies at other locations where increases in tiger shark catch per unit effort (CPUE) have been reported. Significant temporal declines in the average size of tiger sharks occurred at four of the nine locations analysed (p<. 0.05), which may be indicative of fishing reducing abundance in these areas. Given the long term nature of shark control programs along the Australian east coast, effects on local abundance should have been evident many years ago, which suggests that factors other than the effects of shark control programs have also contributed to the decline. While reductions in catch rate are consistent with a decline in tiger shark abundance, this interpretation should be made with caution, as the inter-annual CPUE varies considerably at most locations. Nevertheless, the overall downward trend, particularly in southern Queensland, indicates that current fishing pressures on the species may be unsustainable. © 2012 Elsevier B.V.

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The crown ethers, 2,3-benzo-1,4,7,10,13-pentaoxa-cyclopentadeca-2-ene and 2,3, ll,12-dibenzo-l,4,7,10,13,16-hexaoxscyclooctadeca-2,11-diene are incorporated into H,N'-ethylenebis(acetylacetoneimino) nickel(II) and copper(II), phenol, and β-naphthol by diazo coupling reactions. The selective nature of the coupling reaction has-been demonstrated by the isolation of both asymmetric mono- and symmetric bis(glyoxalarylcrownhydrazoneimino) metal(II) complexes. An interesting binuclear complex containing two intramolecularly rearranged (glyoxal-hydrazonearylimino) metal(II) groups joined by 18-crown-6 result8 when bis(arenediazonium)-18-crown-6 is coupled with the metal(I1) Schiff bases. The substituted ethers form cationic salts with NaClO4, KCNS, NH4CNS, 14g(CNS)2 and Ca(CNS)2. All the synthesised ethers exhibit ion selectivity sequence as K+ > Na+ and Ca2+ > Mg2+.

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Pond apple usually occurs in swampy areas, but mechanical control may be a viable option in some locations during drier periods. Two machines, the Positrack™ and the Tracksaw™, have been trialled for initial kill rate, amount of follow-up control required, safety to field operators, cost-efficiency and selectivity (effect on native vegetation), compared to other control options. The Positrack™ is a tracked bobcat with a slasher-type attachment that cuts individual trees off near ground level and mulches them. It has no on-board herbicide application capability and requires an additional on-ground operator to apply herbicide by hand. The Tracksaw™ is a tracked mini-excavator with a chainsaw bar and spray applicator on the boom that cuts individual trees off near ground level and applies chemical immediately to the cut stump, requiring only a single operator. Initial trials were done in infestations of similar sizes and densities at the Daintree (Positrack™) and in Innisfail (Tracksaw™) in late 2009. Kill rates to date are 83% for Positrack™ mechanical, 95% for Positrack™ mechanical plus herbicide, and 78% for the Tracksaw™ combined treatment. If ongoing comparison proves either of these machines to be more cost effective, selective, and safer than traditional control methods, mechanical control methods may become more widely used.

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Purpose In the context of demographic and economic changes, helping mature age job seekers find employment is imperative. The purpose of this paper is to examine mature age job seekers’ proactive personality as a moderator of the relationship between age and job search intensity; and to examine job search self-efficacy as a mediator of this moderation effect. It was hypothesized that the generally negative relationships between age and job search self-efficacy and intensity are weaker among job seekers with a more proactive personality. Design/methodology/approach In total, 188 job seekers between 40 and 64 years completed an online questionnaire. Data were analyzed using structural equation modeling. Findings Consistent with previous research, age was negatively related to job search intensity. Proactive personality was positively related to job search intensity and moderated the relationship between age and job search intensity. Extending previous research, proactive personality also positively predicted job search self-efficacy and moderated the relationship between age and job search self-efficacy which, in turn, positively predicted job search intensity. Research limitations/implications Potential limitations of the study include the cross-sectional design, sample selectivity, and the omission of possibly important control variables. Practical implications Practitioners, organizations, and societies concerned with helping mature age job seekers find employment could provide additional support to those with a less proactive personality and low job search self-efficacy. Originality/value This study extends previous research by showing that mature age job seekers’ job search self-efficacy mediates the moderating effect of proactive personality on the relationship between age and job search intensity.

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Long-term unemployment of older people can have severe consequences for individuals, communities and ultimately economies, and is therefore a serious concern in countries with an ageing population. However, the interplay of chronological age and other individual difference characteristics in predicting older job seekers' job search is so far not well understood. This study investigated relationships among age, proactive personality, occupational future time perspective (FTP) and job search intensity of 182 job seekers between 43 and 77 years in Australia. Results were mostly consistent with expectations based on a combination of socio-emotional selectivity theory and the notion of compensatory psychological resources. Proactive personality was positively related to job search intensity and age was negatively related to job search intensity. Age moderated the relationship between proactive personality and job search intensity, such that the relationship was stronger at higher compared to lower ages. One dimension of occupational FTP (perceived remaining time left in the occupational context) mediated this moderating effect, but not the overall relationship between age and job search intensity. Implications for future research, including the interplay of occupational FTP and proactive personality, and some tentative practical implications are discussed.

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Porphyrins appended with crown ether, benzo-15-crown-5, at the methine positions have been synthesized and characterized. The fully and partially substituted porphyrins and their metallo (Co, Cu, and Zn) derivatives describe one or more ether cavities in the periphery that are capable of recognizing spherical cations. The ability of these macrocycles to complex cations (Na+, K+, Mg2+, Ca2+, Ba2', and NH4+) is investigated by use of visible, 'H NMR, ESR, and emission spectral studies. The tetrasubstituted crown porphyrin (TCP) exhibits very high selectivity for K+. The cations (K', Ba2+, and NH4+) that require two crown ether cavities for complexation promote dimerization of the porphyrins. The ESR study of the cation-induced porphyrin dimers reveals axial symmetry with the porphyrin planes separated by -4.2 A. This distance increases from the fully substituted to partially substituted porphyrins. The cations (K', Ba2+, and NH4') quench efficiently the fluorescence of the free base porphyrins and their metallo derivatives. The quenching process is attributed to the steric geometry of the dimers.