Mitochondrial bioenergetics and redox state are unaltered in Trypanosoma cruzi isolates with compromised mitochondrial complex I subunit genes

In trypanosomatids the involvement of mitochondrial complex I in NADH oxidation has long been debated. Here, we took advantage of natural Trypanosoma cruzi mutants which present conspicuous deletions in ND4, ND5 and ND7 genes coding for complex I subunits to further investigate its functionality. Mitochondrial bioenergetics of wild type and complex I mutants showed no significant differences in oxygen consumption or respiratory control ratios in the presence of NADH-linked substrates or FADH(2)-generating succinate. No correlation could be established between mitochondrial membrane potentials and ND deletions. Since release of reactive oxygen species occurs at complex I, we measured mitochondrial H(2)O(2) formation induced by different substrates. Significant differences not associated to ND deletions were observed among the parasite isolates, demonstrating that these mutations are not important for the control of oxidant production. Our data support the notion that complex I has a limited function in T. cruzi.

New phosphinate ligand synthesis and its effect on optical properties of the europium beta-diketonate complex

The synthesis and characterization of a new organic ligand monooctyldiphenylphosphinate (L) is described, as well as a new Eu(3+) diketonate complex [Eu(tta)(3)(L)(2)] (tta = thenoyltrifluoracetone). The ligand (L) was formed by substitution reaction (80% yield) and characterized by uni- and bidimensional (1)H, (13)C and (31)P NMR experiments, to confirm its molecular structure. The coordination of (L) to Eu(3+) in the complex [Eu(tta)(3)(L)(2)] was confirmed by FT-IR spectra. The emission spectra present the same profile when excited in Eu(3+) or in the ligands, suggesting an energy transfer from ligands to Eu(3+) ions. The emission spectra of the precursor [Eu(tta)(3)(H(2)O)(2)], and [Eu(tta)(3)(L(2))] present bands arising from f-f intra-configurational transitions. The only (5)D(0)-(7)F(0) transition shows the presence of at least one site without symmetry center. The FWHM of such transition is 7 cm(-1) and 57 cm(-1) for [Eu(tta)(3)(H(2)O)(2)] and [Eu(tta)(3)(L)(2)] complexes, respectively. This widening is provided by the presence of large groups around Eu(3+) ion. The calculated intensity parameters Omega(2) and Omega(4) show that the interaction features between center-ion and ligand are different; the small value of Omega(4) is related to long range effects of alkyl chain. The Langmuir isotherms of this ligand and complex have been investigated although their hydrolysis in water subphase does not allow stable monolayers. (C) 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim

Magnetic fabric of Araguainha complex impact structure (Central Brazil): Implications for deformation mechanisms and central uplift formation

The weakening mechanisms involved in the collapse of complex impact craters are controversial. The Araguainha impact crater, in Brazil, exposes a complex structure of 40 km in diameter, and is an excellent object to address this issue. Its core is dominated by granite. In addition to microstructural observations, magnetic studies reveal its internal fabric acquired during the collapse phase. All granite samples exhibit impact-related planar deformation features (PDFs) and planar fractures (PFs), which were overprinted by cataclasis. Cataclastic deformation has evolved from incipient brittle fracturing to the development of discrete shear bands in the center of the structure. Fracture planes are systematically decorated by tiny grains (<10 mu m) of magnetite and hematite, and the orientation of magnetic lineation and magnetic foliation obtained by the anisotropies of magnetic susceptibility (AMS) and anhysteretic remanence (AAR) are perfectly coaxial in all studied sites. Therefore, we could track the orientation of deformation features which are decorated by iron oxides using the AMS and AAR. The magnetic fabrics show a regular pattern at the borders of the central peak, with orientations consistent with the fabric of sediments at the crater's inner collar and complex in the center of the structure. Both the cataclastic flow revealed from microstructural observations and the structural pattern of the magnetic anisotropy match the predictions from numerical models of complex impact structures. The widespread occurrence of cataclasis in the central peak, and its orientations revealed by magnetic studies indicate that acoustic fluidization likely operates at all scales, including the mineral scales. The cataclastic flow made possible by acoustic fluidization results in an apparent plastic deformation at the macroscopic scale in the core. (C) 2012 Elsevier B.V. All rights reserved.

Hundertneunundzwanzig Xe NMR for investigations of complex and dynamic systems

In this work, the remarkable versatility and usefulness of applications of Xe-129 NMR experiments is further extended. The application of Xe-129 NMR spectroscopy to very different system is studied, including dynamic and static, solid and liquid, porous and non-porous systems. Using the large non-equilibrium polarization created by hyperpolarization of Xe-129, time-resolved NMR measurements can be used for the online-monitoring of dynamic systems. In the first part of this work, several improvements for medical applications of hyperpolarized Xe-129 are achieved and their feasibility shown experimentally. A large gain in speed and reproducibility of the accumulation process of Xe-129 as ice and an enhancement of the usable polarization in any experiment requiring prior accumulation are achieved. An enhancement of the longitudinal relaxation time of Xe-129 is realized by admixture of a buffer gas during the storage of hyperpolarized Xe-129. Pursuing the efforts of simplifying the accumulation process and enhancing the storage time of hyperpolarized Xe-129 will allow for a wider use of the hyperpolarized gas in (medical) MRI experiments. Concerning the use of hyperpolarized Xe-129 in MRI, the influence of the diffusion coefficient of the gas on parameters of the image contrast is experimentally demonstrated here by admixture of a buffer gas and thus changing the diffusion coefficient. In the second part of this work, a polymer system with unique features is probed by Xe-129 NMR spectroscopy, proving the method to be a valuable tool for the characterization of the anisotropic properties of semicrystalline, syndiotactic polystyrene films. The polymer films contain hollow cavities or channels with sizes in the sub-nanometer range, allowing for adsorption of Xe-129 and subsequent NMR measurements. Despite the use of a ’real-world’ system, the transfer of the anisotropic properties from the material to adsorbed Xe-129 atoms is shown, which was previously only known for fully crystalline materials. The anisotropic behavior towards atomar guests inside the polymer films is proven here for the first time for one of the phases. For the polymer phase containing nanochannels, the dominance of interactions between Xe-129 atoms in the channels compared to interactions between Xe atoms and the channel walls are proven by measurements of a powder sample of the polymer material and experiments including the rotation of the films in the external magnetic field as well as temperature-dependent measurements. The characterization of ’real-world’ systems showing very high degrees of anisotropy by Xe-129 are deemed to be very valuable in future applications. In the last part of this work, a new method for the online monitoring of chemical reactions has been proposed and its feasibility and validity are experimentally proven. The chemical shift dependence of dissolved Xe-129 on the composition of a reaction mixture is used for the online monitoring of free-radical miniemulsion polymerization reactions. Xe-129 NMR spectroscopy provides an excellent method for the online monitoring of polymerization reactions, due to the simplicity of the Xe-129 NMR spectra and the simple relationship between the Xe-129 chemical shift and the reaction conversion. The results of the time-resolved Xe-129 NMR measurements are compared to those from calorimetric measurements, showing a good qualitative agreement. The applicability of the new method to reactions other than polymerization reactions is investigated by the online monitoring of an enzymatic reaction in a miniemulsion. The successful combination of the large sensitivity of Xe-129, the NMR signal enhancements due to hyperpolarization, and the solubility of Xe-129 gives access to the large new field of investigations of chemical reaction kinetics in dynamic and complex systems like miniemulsions.

Planned complex suicide: Self-strangulation and plaster ingestion

The literature contains many case reports of planned and complex suicides, which combine various methods to commit suicide. In this article, we present the anomalous suicide of an adult male by strangulation with a belt and simultaneous ingestion of plaster. The specific circumstances of the case are described and relevant literature is briefly reviewed. This case vignette illustrates one example of the wide ranging methods employed in suicides and may represent the first reported case of a fatal complex suicide involving self-strangulation and plaster ingestion. Knowledge of varied and sometimes unusual suicide methods is important to the forensic investigator to prevent unnecessary criminal investigation and to reliably and confidently establish manner and cause of death.

A unifying approach for haplotype analysis of quantitative traits in family-based association studies: Testing and estimating gene-environment interactions with complex exposure variables

We propose robust and e±cient tests and estimators for gene-environment/gene-drug interactions in family-based association studies. The methodology is designed for studies in which haplotypes, quantitative pheno- types and complex exposure/treatment variables are analyzed. Using causal inference methodology, we derive family-based association tests and estimators for the genetic main effects and the interactions. The tests and estimators are robust against population admixture and strati¯cation without requiring adjustment for confounding variables. We illustrate the practical relevance of our approach by an application to a COPD study. The data analysis suggests a gene-environment interaction between a SNP in the Serpine gene and smok- ing status/pack years of smoking that reduces the FEV1 volume by about 0.02 liter per pack year of smoking. Simulation studies show that the pro- posed methodology is su±ciently powered for realistic sample sizes and that it provides valid tests and effect size estimators in the presence of admixture and stratification.

Rigorous Design of Complex Distillation Columns Using Process Simulators and the Particle Swarm Optimization Algorithm

We present a derivative-free optimization algorithm coupled with a chemical process simulator for the optimal design of individual and complex distillation processes using a rigorous tray-by-tray model. The proposed approach serves as an alternative tool to the various models based on nonlinear programming (NLP) or mixed-integer nonlinear programming (MINLP) . This is accomplished by combining the advantages of using a commercial process simulator (Aspen Hysys), including especially suited numerical methods developed for the convergence of distillation columns, with the benefits of the particle swarm optimization (PSO) metaheuristic algorithm, which does not require gradient information and has the ability to escape from local optima. Our method inherits the superstructure developed in Yeomans, H.; Grossmann, I. E.Optimal design of complex distillation columns using rigorous tray-by-tray disjunctive programming models. Ind. Eng. Chem. Res.2000, 39 (11), 4326–4335, in which the nonexisting trays are considered as simple bypasses of liquid and vapor flows. The implemented tool provides the optimal configuration of distillation column systems, which includes continuous and discrete variables, through the minimization of the total annual cost (TAC). The robustness and flexibility of the method is proven through the successful design and synthesis of three distillation systems of increasing complexity.

Contrast sensitivity for complex and random gratings

This thesis studied the effect of (i) the number of grating components and (ii) parameter randomisation on root-mean-square (r.m.s.) contrast sensitivity and spatial integration. The effectiveness of spatial integration without external spatial noise depended on the number of equally spaced orientation components in the sum of gratings. The critical area marking the saturation of spatial integration was found to decrease when the number of components increased from 1 to 5-6 but increased again at 8-16 components. The critical area behaved similarly as a function of the number of grating components when stimuli consisted of 3, 6 or 16 components with different orientations and/or phases embedded in spatial noise. Spatial integration seemed to depend on the global Fourier structure of the stimulus. Spatial integration was similar for sums of two vertical cosine or sine gratings with various Michelson contrasts in noise. The critical area for a grating sum was found to be a sum of logarithmic critical areas for the component gratings weighted by their relative Michelson contrasts. The human visual system was modelled as a simple image processor where the visual stimuli is first low-pass filtered by the optical modulation transfer function of the human eye and secondly high-pass filtered, up to the spatial cut-off frequency determined by the lowest neural sampling density, by the neural modulation transfer function of the visual pathways. The internal noise is then added before signal interpretation occurs in the brain. The detection is mediated by a local spatially windowed matched filter. The model was extended to include complex stimuli and its applicability to the data was found to be successful. The shape of spatial integration function was similar for non-randomised and randomised simple and complex gratings. However, orientation and/or phase randomised reduced r.m.s contrast sensitivity by a factor of 2. The effect of parameter randomisation on spatial integration was modelled under the assumption that human observers change the observer strategy from cross-correlation (i.e., a matched filter) to auto-correlation detection when uncertainty is introduced to the task. The model described the data accurately.

Building cliques and alliances as practices to 'make things happen' in complex networks

The Roma population has become a policy issue highly debated in the European Union (EU). The EU acknowledges that this ethnic minority faces extreme poverty and complex social and economic problems. 52% of the Roma population live in extreme poverty, 75% in poverty (Soros Foundation, 2007, p. 8), with a life expectancy at birth of about ten years less than the majority population. As a result, Romania has received a great deal of policy attention and EU funding, being eligible for 19.7 billion Euros from the EU for 2007-2013. Yet progress is slow; it is debated whether Romania's government and companies were capable to use these funds (EurActiv.ro, 2012). Analysing three case studies, this research looks at policy implementation in relation to the role of Roma networks in different geographical regions of Romania. It gives insights about how to get things done in complex settings and it explains responses to the Roma problem as a „wicked‟ policy issue. This longitudinal research was conducted between 2008 and 2011, comprising 86 semi-structured interviews, 15 observations, and documentary sources and using a purposive sample focused on institutions responsible for implementing social policies for Roma: Public Health Departments, School Inspectorates, City Halls, Prefectures, and NGOs. Respondents included: governmental workers, academics, Roma school mediators, Roma health mediators, Roma experts, Roma Councillors, NGOs workers, and Roma service users. By triangulating the data collected with various methods and applied to various categories of respondents, a comprehensive and precise representation of Roma network practices was created. The provisions of the 2001 „Governmental Strategy to Improve the Situation of the Roma Population‟ facilitated forming a Roma network by introducing special jobs in local and central administration. In different counties, resources, people, their skills, and practices varied. As opposed to the communist period, a new Roma elite emerged: social entrepreneurs set the pace of change by creating either closed cliques or open alliances and by using more or less transparent practices. This research deploys the concept of social/institutional entrepreneurs to analyse how key actors influence clique and alliance formation and functioning. Significantly, by contrasting three case studies, it shows that both closed cliques and open alliances help to achieve public policy network objectives, but that closed cliques can also lead to failure to improve the health and education of Roma people in a certain region.

Complex skills and academic writing:a review of evidence about the types of learning required to meet core assessment criteria

Assessment criteria are increasingly incorporated into teaching, making it important to clarify the pedagogic status of the qualities to which they refer. We reviewed theory and evidence about the extent to which four core criteria for student writing-critical thinking, use of language, structuring, and argument-refer to the outcomes of three types of learning: generic skills learning, a deep approach to learning, and complex learning. The analysis showed that all four of the core criteria describe to some extent properties of text resulting from using skills, but none qualify fully as descriptions of the outcomes of applying generic skills. Most also describe certain aspects of the outcomes of taking a deep approach to learning. Critical thinking and argument correspond most closely to the outcomes of complex learning. At lower levels of performance, use of language and structuring describe the outcomes of applying transferable skills. At higher levels of performance, they describe the outcomes of taking a deep approach to learning. We propose that the type of learning required to meet the core criteria is most usefully and accurately conceptualized as the learning of complex skills, and that this provides a conceptual framework for maximizing the benefits of using assessment criteria as part of teaching. © 2006 Taylor & Francis.

Arc crust-magma interaction in the Andean Southern Volcanic Zone from thermobarometry, mineral composition, radiogenic isotope and rare earth element systematics of the Azufre-Planchon-Peteroa volcanic complex, Chile

The Andean Southern Volcanic Zone (SVZ) is a vast and complex continental arc that has been studied extensively to provide an understanding of arc-magma genesis, the origin and chemical evolution of the continental crust, and geochemical compositions of volcanic products. The present study focuses on distinguishing the magma/sub-arc crustal interaction of eruptive products from the Azufre-Planchon-Peteroa (APP 35°15'S) volcanic center and other major centers in the Central SVZ (CSVZ 37°S–42°S), Transitional SVZ (TSVZ 34.3–37.0°S), and Northern SVZ (NSVZ 33°S–34°30'S). New Hf and Nd isotopic and trace element data for SVZ centers are consistent with former studies that these magmas experienced variable depths of crystal fractionation, and that crustal assimilation is restricted to the lower crustal depths with an apparent role of garnet. Thermobarometric calculations applied to magma compositions constrain the depth of magma separation from mantle sources in all segments of the SVZ to(70-90 km). Magmatic separation at the APP complex occurs at an average depth of ~50 km which is confined to the mantle lithosphere and the base of the crust suggesting localized thermal abrasion both reservoirs. Thermobarometric calculations indicate that CSVZ primary magmas arise from a similar average depth of (~54 km) which confines magma separation to the asthenospheric mantle. The northwards along-arc Sr-Nd-Hf isotopic data and LREE enrichment accompanied with HREE depletion of SVZ mafic magmas correlates well with northward increasing crustal thickness and decreasing primary melt separation from mantle source regions indicating an increased involvement of lower crustal components in SVZ magma petrogenesis. ^ The study concludes that the development of mature subduction zones over millions of years of continuous magmatism requires that mafic arc derived melts stagnate at lower crustal levels due to density similarities and emplace at lower crustal depths. Basaltic underplating creates localized hot zone environments below major magmatic centers. These regions of high temperature/partial melting, and equilibration with underplated mafic rocks provides the mechanism that controls trace element and isotopic variability of primary magmas of the TSVZ and NSVZ from their baseline CSVZ-like precursors.^

A First Step Towards Video Enhanced Rubrics for the Formative Assessment of Complex Skills : A literature review and a plea

Paper presentation at the TEA2016 conference, Tallinn, Estonia.

Transcriptome, carbohydrate, and phytohormone analysis of Petunia hybrida reveals a complex disturbance of plant functional integrity under mild chilling stress

Cultivation of chilling-tolerant ornamental crops at lower temperature could reduce the energy demands of heated greenhouses. To provide a better understanding of how sub-optimal temperatures (12 degrees C vs. 16 degrees C) affect growth of the sensitive Petunia hybrida cultivar 'SweetSunshine Williams', the transcriptome, carbohydrate metabolism, and phytohormone homeostasis were monitored in aerial plant parts over 4 weeks by use of a microarray, enzymatic assays and GC-MS/MS. The data revealed three consecutive phases of chilling response. The first days were marked by a strong accumulation of sugars, particularly in source leaves, preferential up-regulation of genes in the same tissue and down-regulation of several genes in the shoot apex, especially those involved in the abiotic stress response. The midterm phase featured a partial normalization of carbohydrate levels and gene expression. After 3 weeks of chilling exposure, a new stabilized balance was established. Reduced hexose levels in the shoot apex, reduced ratios of sugar levels between the apex and source leaves and a higher apical sucrose/hexose ratio, associated with decreased activity and expression of cell wall invertase, indicate that prolonged chilling induced sugar accumulation in source leaves at the expense of reduced sugar transport to and reduced sucrose utilization in the shoot. This was associated with reduced levels of indole-3-acetic acid and abscisic acid in the apex and high numbers of differentially, particularly up-regulated genes, especially in the source leaves, including those regulating histones, ethylene action, transcription factors, and a jasmonate-ZIM-domain protein. Transcripts of one Jumonji C domain containing protein and one expansin accumulated in source leaves throughout the chilling period. The results reveal a dynamic and complex disturbance of plant function in response to mild chilling, opening new perspectives for the comparative analysis of differently tolerant cultivars.

A re-examination of the Ghrelin and Ghrelin receptor genes

The last few years have seen dramatic advances in genomics, including the discovery of a large number of non-coding and antisense transcripts. This has revolutionised our understanding of multifaceted transcript structures found within gene loci and their roles in the regulation of development, neurogenesis and other complex processes. The recent and continuing surge of knowledge has prompted researchers to reassess and further dissect gene loci. The ghrelin gene (GHRL) gives rise to preproghrelin, which in turn produces ghrelin, a 28 amino acid peptide hormone that acts via the ghrelin receptor (growth hormone secretagogue receptor/GHSR 1a). Ghrelin has many important physiological and pathophysiological roles, including the stimulation of growth hormone (GH) release, appetite regulation, and cancer development. A truncated receptor splice variant, GHSR 1b, does not bind ghrelin, but dimerises with GHSR 1a, and may act as a dominant negative receptor. The gene products of ghrelin and its receptor are frequently overexpressed in human cancer While it is well known that the ghrelin axis (ghrelin and its receptor) plays a range of important functional roles, little is known about the molecular structure and regulation of the ghrelin gene (GHRL) and ghrelin receptor gene (GHSR). This thesis reports the re-annotation of the ghrelin gene, discovery of alternative 5’ exons and transcription start sites, as well as the description of a number of novel splice variants, including isoforms with a putative signal peptide. We also describe the discovery and characterisation of a ghrelin antisense gene (GHRLOS), and the discovery and expression of a ghrelin receptor (growth hormone secretagogue receptor/GHSR) antisense gene (GHSR-OS). We have identified numerous ghrelin-derived transcripts, including variants with extended 5' untranslated regions and putative secreted obestatin and C-ghrelin transcripts. These transcripts initiate from novel first exons, exon -1, exon 0 and a 5' extended 1, with multiple transcription start sites. We used comparative genomics to identify, and RT-PCR to experimentally verify, that the proximal exon 0 and 5' extended exon 1 are transcribed in the mouse ghrelin gene, which suggests the mouse and human proximal first exon architecture is conserved. We have identified numerous novel antisense transcripts in the ghrelin locus. A candidate non-coding endogenous natural antisense gene (GHRLOS) was cloned and demonstrates very low expression levels in the stomach and high levels in the thymus, testis and brain - all major tissues of non-coding RNA expression. Next, we examined if transcription occurs in the antisense orientation to the ghrelin receptor gene, GHSR. A novel gene (GHSR-OS) on the opposite strand of intron 1 of the GHSR gene was identified and characterised using strand-specific RT-PCR and rapid amplification of cDNA ends (RACE). GHSR-OS is differentially expressed and a candidate non-coding RNA gene. In summary, this study has characterised the ghrelin and ghrelin receptor loci and demonstrated natural antisense transcripts to ghrelin and its receptor. Our preliminary work shows that the ghrelin axis generates a broad and complex transcriptional repertoire. This study provides the basis for detailed functional studies of the the ghrelin and GHSR loci and future studies will be needed to further unravel the function, diagnostic and therapeutic potential of the ghrelin axis.

CTCombine : rotating and combining CT data with an accurate detector model, to simulate radiotherapy portal imaging at non-zero beam angles

Established Monte Carlo user codes BEAMnrc and DOSXYZnrc permit the accurate and straightforward simulation of radiotherapy experiments and treatments delivered from multiple beam angles. However, when an electronic portal imaging detector (EPID) is included in these simulations, treatment delivery from non-zero beam angles becomes problematic. This study introduces CTCombine, a purpose-built code for rotating selected CT data volumes, converting CT numbers to mass densities, combining the results with model EPIDs and writing output in a form which can easily be read and used by the dose calculation code DOSXYZnrc. The geometric and dosimetric accuracy of CTCombine’s output has been assessed by simulating simple and complex treatments applied to a rotated planar phantom and a rotated humanoid phantom and comparing the resulting virtual EPID images with the images acquired using experimental measurements and independent simulations of equivalent phantoms. It is expected that CTCombine will be useful for Monte Carlo studies of EPID dosimetry as well as other EPID imaging applications.