Hexaaluminate catalysts for the partial oxidation of middle distillate fuels

Studies were conducted on active metals (i.e., Co, Fe and Ni) substituted into the lattice of hexaaluminate compounds to reform liquid hydrocarbon fuels into H2-rich synthesis gas for fuel cell applications. Both the concentration of active metals substituted into the lattice and the different mirror cations, (i.e., Ba, La and Sr) were investigated for their effect on the catalytic properties of the hexaaluminate compound. In these studies, n-tetradecane was used as a model middle distillate fuel. The synthesized catalysts were characterized by a series of techniques including: N2 BET surface area, powder XRD, TPR, H2 pulse chemisorption, bulk elemental analysis by ICP, and surface analysis by XPS.;The catalysts were shown to exhibit P63/mmc crystal symmetry which was indicative of the hexaaluminate structure. TPR experiments on the catalysts indicated that the substitution of cobalt, iron and nickel cations into the lattice stabilized their reducibility. The reduction temperature for the nickel series of catalysts correlated with the type of mirror cation substituted into the lattice. H2 pulse chemisorption performed on reduced nickel hexaaluminate catalysts confirmed that the number of active nickel sites that were reduced in the lattice was influenced by the mirror cation. XPS analysis of LaNi0.4Al11.6O19-delta , SrNi0.4Al11.6O19-delta and BaNi 0.4Al11.6O19-delta catalysts indicated that the variation in the nickel surface concentration of the oxide catalysts also correlated with the mirror cation.;The activity of the synthesized catalysts toward the partial oxidation of n-tetradecane was examined by temperature programmed reaction between 750 to 900°C. Iron substituted into the hexaaluminate lattice was shown to exhibit relatively poor catalytic activity and selectivity at all concentrations during the temperature programmed reaction with n-tetradecane. Cobalt substituted into the hexaaluminate lattice at concentrations of y ≤ 0.8 (LaCo yAl12-yO19-delta) exhibited equally poor catalytic activity and selectivity. However, the LaCoAl11O19-delta catalyst exhibited equilibrium CO and H2 yields.;The LaNiyAl12-yO19-delta (y = 0.2, 0.4, 0.8 and 1.0) series and the MINi0.4Al11.6 O19-delta (MI = Ba, La and Sr) series of catalysts possessed the greatest H2 and CO activity and selectivity over the temperature region examined. Both the LaNi0.2Al11.8O 19-delta and the BaNi0.4Al11.6O19-delta catalysts exhibited sharp increases in H2 yield at 850 and 875°C, respectively. The increase in H2 yield in this region corresponded to a decrease in CH4 yield indicating that the additional H2 produced was derived from CH4.;The role that the mirror cation produced on nickel substituted hexaaluminate stability during n-tetradecane isothermal partial oxidation was also examined. Nickel catalysts with Ba2+ and Sr2+ mirror cations exhibited greater stability during n-tetradecane partial oxidation than did the La3+ cation. The catalytic behavior induced by the mirror cation suggested that its influence on controlling carbon deposition was structural

Combining a Dispersal Model with Network Theory to Assess Habitat Connectivity

Assessing the potential for threatened species to persist and spread within fragmented landscapes requires the identification of core areas that can sustain resident populations and dispersal corridors that can link these core areas with isolated patches of remnant habitat. We developed a set of GIS tools, simulation methods, and network analysis procedures to assess potential landscape connectivity for the Delmarva fox squirrel (DFS; Sciurus niger cinereus), an endangered species inhabiting forested areas on the Delmarva Peninsula, USA. Information on the DFS’s life history and dispersal characteristics, together with data on the composition and configuration of land cover on the peninsula, were used as input data for an individual-based model to simulate dispersal patterns of millions of squirrels. Simulation results were then assessed using methods from graph theory, which quantifies habitat attributes associated with local and global connectivity. Several bottlenecks to dispersal were identified that were not apparent from simple distance-based metrics, highlighting specific locations for landscape conservation, restoration, and/or squirrel translocations. Our approach links simulation models, network analysis, and available field data in an efficient and general manner, making these methods useful and appropriate for assessing the movement dynamics of threatened species within landscapes being altered by human and natural disturbances

Existence and stability of hole solutions to complex Ginzburg-Landau equations

We consider the existence and stability of the hole, or dark soliton, solution to a Ginzburg-Landau perturbation of the defocusing nonlinear Schroedinger equation (NLS), and to the nearly real complex Ginzburg-Landau equation (CGL). By using dynamical systems techniques, it is shown that the dark soliton can persist as either a regular perturbation or a singular perturbation of that which exists for the NLS. When considering the stability of the soliton, a major difficulty which must be overcome is that eigenvalues may bifurcate out of the continuous spectrum, i.e., an edge bifurcation may occur. Since the continuous spectrum for the NLS covers the imaginary axis, and since for the CGL it touches the origin, such a bifurcation may lead to an unstable wave. An additional important consideration is that an edge bifurcation can happen even if there are no eigenvalues embedded in the continuous spectrum. Building on and refining ideas first presented in Kapitula and Sandstede (Physica D, 1998) and Kapitula (SIAM J. Math. Anal., 1999), we show that when the wave persists as a regular perturbation, at most three eigenvalues will bifurcate out of the continuous spectrum. Furthermore, we precisely track these bifurcating eigenvalues, and thus are able to give conditions for which the perturbed wave will be stable. For the NLS the results are an improvement and refinement of previous work, while the results for the CGL are new. The techniques presented are very general and are therefore applicable to a much larger class of problems than those considered here.Comment: 41 pages, 4 figures, submitte

ABC's of Writing Medical Papers in English

Publishing medical papers in English is important as English remains the predominant language for most medical papers (both electronic and traditional journal publications). In addition, journals with the highest impact factors are published in English and a publication in English thus enhances the visibility of authors and their institutions, and is important for promotion in some academic centers. This article reviews the basic principles that will help you successfully publish a manuscript in English. Although other books and articles are available on this subject, there are relatively few references. The present article is based on this author's experience of publishing nearly 400 articles in English. It will emphasize writing original articles, but the principles can be applied to virtually any type of manuscript

The transcriptional repressor protein NsrR senses nitric oxide directly via a [2Fe-2S] cluster

The regulatory protein NsrR, a member of the Rrf2 family of transcription repressors, is specifically dedicated to sensing nitric oxide (NO) in a variety of pathogenic and non-pathogenic bacteria. It has been proposed that NO directly modulates NsrR activity by interacting with a predicted [Fe-S] cluster in the NsrR protein, but no experimental evidence has been published to support this hypothesis. Here we report the purification of NsrR from the obligate aerobe Streptomyces coelicolor. We demonstrate using UV-visible, near UV CD and EPR spectroscopy that the protein contains an NO-sensitive [2Fe-2S] cluster when purified from E. coli. Upon exposure of NsrR to NO, the cluster is nitrosylated, which results in the loss of DNA binding activity as detected by bandshift assays. Removal of the [2Fe-2S] cluster to generate apo-NsrR also resulted in loss of DNA binding activity. This is the first demonstration that NsrR contains an NO-sensitive [2Fe-2S] cluster that is required for DNA binding activity

Forecasting Random Walks under Drift Instability

This paper considers forecast averaging when the same model is used but estimation is carried out over different estimation windows. It develops theoretical results for random walks when their drift and/or volatility are subject to one or more structural breaks. It is shown that compared to using forecasts based on a single estimation window, averaging over estimation windows leads to a lower bias and to a lower root mean square forecast error for all but the smallest of breaks. Similar results are also obtained when observations are exponentially down-weighted, although in this case the performance of forecasts based on exponential down-weighting critically depends on the choice of the weighting coefficient. The forecasting techniques are applied to monthly inflation series of 21 OECD countries and it is found that average forecasting methods in general perform better than using forecasts based on a single estimation window

Stromal cell-derived factor and granulocyte-monocyte colony-stimulating factor form a combined neovasculogenic therapy for ischemic cardiomyopathy

ObjectiveIschemic heart failure is an increasingly prevalent global health concern with major morbidity and mortality. Currently, therapies are limited, and novel revascularization methods might have a role. This study examined enhancing endogenous myocardial revascularization by expanding bone marrow-derived endothelial progenitor cells with the marrow stimulant granulocyte-monocyte colony-stimulating factor and recruiting the endothelial progenitor cells with intramyocardial administration of the potent endothelial progenitor cell chemokine stromal cell-derived factor.MethodsIschemic cardiomyopathy was induced in Lewis rats (n = 40) through left anterior descending coronary artery ligation. After 3 weeks, animals were randomized into 4 groups: saline control, granulocyte-monocyte colony-stimulating factor only (GM-CSF only), stromal cell-derived factor only (SDF only), and combined stromal cell-derived factor/granulocyte-monocyte colony-stimulating factor (SDF/GM-CSF) (n = 10 each). After another 3 weeks, hearts were analyzed for endothelial progenitor cell density by endothelial progenitor cell marker colocalization immunohistochemistry, vasculogenesis by von Willebrand immunohistochemistry, ventricular geometry by hematoxylin-and-eosin microscopy, and in vivo myocardial function with an intracavitary pressure-volume conductance microcatheter.ResultsThe saline control, GM-CSF only, and SDF only groups were equivalent. Compared with the saline control group, animals in the SDF/GM-CSF group exhibited increased endothelial progenitor cell density (21.7 ± 3.2 vs 9.6 ± 3.1 CD34+/vascular endothelial growth factor receptor 2–positive cells per high-power field, P = .01). There was enhanced vascularity (44.1 ± 5.5 versus 23.8 ± 2.2 von Willebrand factor-positive vessels per high-power field, P = .007). SDF/GM-CSF group animals experienced less adverse ventricular remodeling, as manifested by less cavitary dilatation (9.8 ± 0.1 mm vs 10.1 ± 0.1 mm [control], P = .04) and increased border-zone wall thickness (1.78 ± 0.19 vs 1.41 ± 0.16 mm [control], P = .03). (SDF/GM-CSF group animals had improved cardiac function compared with animals in the saline control group (maximum pressure: 93.9 ± 3.2 vs 71.7 ± 3.1 mm Hg, P < .001; maximum dP/dt: 3513 ± 303 vs 2602 ± 201 mm Hg/s, P < .05; cardiac output: 21.3 ± 2.7 vs 13.3 ± 1.3 mL/min, P < .01; end-systolic pressure-volume relationship slope: 1.7 ± 0.4 vs 0.5 ± 0.2 mm Hg/μL, P < .01.)ConclusionThis novel revascularization strategy of bone marrow stimulation and intramyocardial delivery of the endothelial progenitor cell chemokine stromal cell-derived factor yielded significantly enhanced myocardial endothelial progenitor cell density, vasculogenesis, geometric preservation, and contractility in a model of ischemic cardiomyopathy

Associations Between Anticholinergic Medication Exposure and Adverse Health Outcomes in Older People with Frailty: A Systematic Review and Meta-analysis

Introduction There are robust associations between use of anticholinergic medicines and adverse effects in older people. However, the nature of these associations for older people living with frailty is yet to be established. Objectives The aims were to identify and investigate associations between anticholinergics and adverse outcomes in older people living with frailty and to investigate whether exposure is associated with greater risks according to frailty status. Methods MEDLINE, CINAHL, EMBASE, Cochrane Database of Systematic Reviews, Web of Science and PsycINFO were searched to 1 August 2019. Observational studies reporting associations between anticholinergics and outcomes in older adults (average age ≥ 65 years) that reported frailty using validated measures were included. Primary outcomes were physical impairment, cognitive dysfunction, and change in frailty status. Risk of bias was evaluated using the Cochrane Risk of Bias In Non-randomised Studies of Interventions (ROBINS-I) tool. Meta-analysis was undertaken where appropriate. Results Thirteen studies (21,516 participants) were included (ten community, one residential aged-care facility and two hospital studies). Observed associations included reduced ability for chair standing, slower gait speeds, poorer physical performance, increased risk of falls and mortality. Conflicting results were reported for grip strength, timed up and go test, cognition and activities of daily living. No associations were observed for transitions between frailty states, psychological wellbeing or benzodiazepine-related adverse reactions. There was no clear evidence of differences in risks according to frailty status. Conclusions Anticholinergics are associated with adverse outcomes in older people living with frailty; however, the literature has significant methodological limitations. There is insufficient evidence to suggest greater risks based on frailty, and there is an urgent need to evaluate this further in well-designed studies stratifying by frailty

Clinicians' caseload management behaviours as explanatory factors in patients' length of time on caseloads : a predictive multilevel study in paediatric community occupational therapy

Peer reviewedPublisher PD

Passive Multiplexer Test Structure For Fast and Accurate Contact and Via Fail-Rate Evaluation

Abstract-Complexity of integrated circuits has led to millions of contacts and vias on every chip. To allow accurate yield evaluation, it is required to determine fail rates of 10 faults per billion, which requires test structures with huge chains of 1 million or more contacts and vias. At the same time, contacts and vias are getting smaller, and thus their resistance is increasing for every new technology node. Consequently, the resistance of such chains becomes impossible to measure. To overcome this limit without increasing the number of measurement pads, we are proposing a passive multiplexer array of via chains, which breaks up a huge contact-via chain in many individually measurable subchains. Accuracy of fail rates will be increased since the fail rate can be determined based on many subchains, instead of being determined based on only one huge chain. Furthermore, this test structure better supports failure analysis since it is faster to locate a faulty contact or via. No additional devices or process steps are required which allows implementation as short flows for fast process problem debugging