Identifying important differences in mass spectra generated by secondary ion mass spectrometry (TOF-SIMS) in a tribochemical study

In order to better understand the lubricating properties of diesel fuel, species that were present on tribological surfaces were investigated using secondary ion time-of-flight mass spectrometry (TOF–SIMS). Traditionally, only certain species that are expected to be present at the interface are investigated and their presence or absence is used to make conclusions regarding the mechanism of lubrication. In this work, an alternative and complementary approach to data analysis and interpretation is proposed, previously demonstrated for TOF–SIMS and based on multivariate analysis methods, where the mass spectral data are investigated more comprehensively. The main objective was to interpret variation within and between different areas of a tested surface and ultimately to contribute to the understanding of the tribochemical reactions that occur at the interface. The validity of this approach was confirmed when the palmitate ion (which would normally be targeted) was shown to contribute significantly (together with other ions) to chemical differences between scratched and unscratched areas of the surface.Sasol (Sasol Technology,Fuels Research) and the National Research Foundation (DAAD-NRF).http://link.springer.com/journal/112492015-10-31hb201

CO2 conversion via coupled plasma-electrolysis process

Surplus renewable electricity used to convert CO2 into CO, the building block of liquid fuels, advances the energy transition by enabling large-scale, long-term energy storage and the synthesis of fuel for long-haul transportation. Among the various technologies developed, renewable electricity driven conversion of CO2 by high-temperature electrolysis and by plasmolysis offer a tantalising potential. High-temperature electrolysis is characterized by high-yield and energy-efficiency and the direct separation of the CO2 dissociation products CO and O2. However, the difficulty to break the carbon-oxygen double bond poses challenging requirements on electrode materials. CO2 plasmolysis on the other hand, offers a similar energy efficiency, does not employ scarce materials, is easy to upscale, but requires efficient gas separation and recuperation because the produced CO remains mixed with O2 and residual CO2. Here, we demonstrate that the coupling of the two processes leads to a renewable-electricity-driven route for producing CO from CO2, overcoming the main bottleneck of CO2 plasmolysis. A simulated CO2 plasmolysis gas mixture is supplied to a high-temperature electrolyser to separate the product gases electrochemically. Our results show that the product stream of the coupled-process contains 91% less oxygen and 138% more CO compared with the bare plasmolysis process. Apart from upgrading the produced gas mixture, this coupled approach benefits from material stability. Durability tests (~100 h) show better stability in coupled operation when compared with conventional CO2 electrolysis. Synergy between plasmolysis and electrolysis opens up a novel route to efficient CO2 conversion into valuable CO feedstock for the synthesis of long-chain hydrocarbons

Nematode-based indices in soil ecology: Application, utility, and future directions

14 Pág.The health and functioning of soil ecosystems are the foundation of sustainable food production and land management. Of key importance in achieving sustainability, is the frequent measurement of soil health, and indices based on the community structure of nematodes are amongst the most widely used toolsets by soil ecologists. Thirty years after the development of the Maturity Index, we aimed to evaluate the application, utility, and future directions of nematode-based indices (NBIs). This review focused on NBIs that are calculated using the coloniser-persister classification of nematodes. Data from 672 empirical studies in terrestrial environments revealed that the NBIs presented a dissimilar usage trend. The Channel Index and Metabolic Footprints showed the strongest increase in application rates over time, thus indicating a greater interest in studying decomposition pathways and ecosystem functioning, respectively. Furthermore, nematode-based indices were mostly applied in agricultural systems associated with herbaceous crops and in studies investigating, for example, soil nutrient enrichment following manure and/or inorganic fertilizer application. We further provide a framework for selecting a focus-orientated subset of NBIs for testing hypotheses based on the underlying ecological mechanisms. Also, we highlight important considerations, including the unexpected behaviour of some nematode taxa, in the interpretation of NBIs. The improvement of NBIs relies on advancing our understanding of the autecology of nematodes. Finally, we deliver insight into the further development of NBIs considering recent methodological advancements. We highlight that NBIs have been and might become increasingly important in providing valuable information on soil ecosystem health and functioning, especially considering the urgent need for more sustainable land use.The contribution of JHS was funded by the Deutsche Forschungsgemeinschaft (DFG, German Research Foundation) — :— Project no. 420414676: “The self-regulatory potential of agro-ecosystems: Using nematodes as indicators for legume disease suppressive soils”.Peer reviewe

Pathogenic Variants in MT-ATP6: A United Kingdom-Based Mitochondrial Disease Cohort Study

Distinct clinical syndromes have been associated with pathogenic MT-ATP6 variants. In this cohort study, we identified 125 individuals (60 families) including 88 clinically affected individuals and 37 asymptomatic carriers. Thirty-one individuals presented with Leigh syndrome and 7 with neuropathy ataxia retinitis pigmentosa. The remaining 50 patients presented with variable nonsyndromic features including ataxia, neuropathy, and learning disability. We confirmed maternal inheritance in 39 families and demonstrated that tissue segregation patterns and phenotypic threshold are variant dependent. Our findings suggest that MT-ATP6-related mitochondrial DNA disease is best conceptualized as a mitochondrial disease spectrum disorder and should be routinely included in genetic ataxia and neuropathy gene panels. ANN NEUROL 2019;86:310-31

Identification of Novel Functional Inhibitors of Acid Sphingomyelinase

We describe a hitherto unknown feature for 27 small drug-like molecules, namely functional inhibition of acid sphingomyelinase (ASM). These entities named FIASMAs (Functional Inhibitors of Acid SphingoMyelinAse), therefore, can be potentially used to treat diseases associated with enhanced activity of ASM, such as Alzheimer's disease, major depression, radiation- and chemotherapy-induced apoptosis and endotoxic shock syndrome. Residual activity of ASM measured in the presence of 10 µM drug concentration shows a bimodal distribution; thus the tested drugs can be classified into two groups with lower and higher inhibitory activity. All FIASMAs share distinct physicochemical properties in showing lipophilic and weakly basic properties. Hierarchical clustering of Tanimoto coefficients revealed that FIASMAs occur among drugs of various chemical scaffolds. Moreover, FIASMAs more frequently violate Lipinski's Rule-of-Five than compounds without effect on ASM. Inhibition of ASM appears to be associated with good permeability across the blood-brain barrier. In the present investigation, we developed a novel structure-property-activity relationship by using a random forest-based binary classification learner. Virtual screening revealed that only six out of 768 (0.78%) compounds of natural products functionally inhibit ASM, whereas this inhibitory activity occurs in 135 out of 2028 (6.66%) drugs licensed for medical use in humans

Mitochondrial physiology

As the knowledge base and importance of mitochondrial physiology to evolution, health and disease expands, the necessity for harmonizing the terminology concerning mitochondrial respiratory states and rates has become increasingly apparent. The chemiosmotic theory establishes the mechanism of energy transformation and coupling in oxidative phosphorylation. The unifying concept of the protonmotive force provides the framework for developing a consistent theoretical foundation of mitochondrial physiology and bioenergetics. We follow the latest SI guidelines and those of the International Union of Pure and Applied Chemistry (IUPAC) on terminology in physical chemistry, extended by considerations of open systems and thermodynamics of irreversible processes. The concept-driven constructive terminology incorporates the meaning of each quantity and aligns concepts and symbols with the nomenclature of classical bioenergetics. We endeavour to provide a balanced view of mitochondrial respiratory control and a critical discussion on reporting data of mitochondrial respiration in terms of metabolic flows and fluxes. Uniform standards for evaluation of respiratory states and rates will ultimately contribute to reproducibility between laboratories and thus support the development of data repositories of mitochondrial respiratory function in species, tissues, and cells. Clarity of concept and consistency of nomenclature facilitate effective transdisciplinary communication, education, and ultimately further discovery

Novel analytical approaches for studying degradation in polypropylene and propylene-1-pentene copolymers

Thesis (DSc (Chemistry and Polymer Science))--University of Stellenbosch, 2006.Commercial polyolefins degrade under the influence of light, heat, chemical and mechanical factors. They are therefore stabilised to ensure that they maintain performance characteristics during their service life. Degradation results in changes in the molar mass, molar mass distribution, chemical composition and chemical composition distribution. Classical analytical techniques only provide averaged values of these properties. Much information is available in the open literature on the changes in molar mass, molar mass distribution and chemical composition of polypropylene upon degradation, but no information was available on the changes in chemical composition distribution (CCD) during degradation. This study describes the use of the following analytical techniques to study this: temperature rising elution fractionation (TREF), crystallisation analysis fractionation (CRYSTAF) and coupled size exclusion chromatography-Fourier transform infrared analysis (SEC-FTIR). The CRYSTAF results complimented those obtained by classical techniques: there was a broadening of the crystallisation peak (CCD), an increase in the soluble fraction and a decrease in crystallisation temperatures. SEC-FTIR analysis showed that most of the degraded products were concentrated in the low molar mass regions. TREF analysis was used to separate a degraded sample into fractions of different degrees of degradation. It was then possible to study the spatial heterogeneity in a thick, degraded polypropylene sample using SEC, FTIR and CRYSTAF. The degradation behaviour of selected Sasol propylene-1-pentene random copolymers was investigated. CRYSTAF, SEC-FTIR and TREF analyses provided information on the thermo-oxidative degradation behaviour differences between unstabilised polypropylene homopolymers and these propylene-1-pentene copolymers. It was found that the pentene copolymers degraded significantly faster compared to the homopolymers, even at low levels of pentene (< 3%). The reduction in stability was virtually linear with an increase in pentene content (up to 8 mol% pentene), indicating that higher levels of primary stabilisers are needed to ensure similar life spans for the Sasol propylene-1-pentene copolymers. The extrusion stability of the propylene-1-pentene copolymers was, however, similar to that of the polypropylene homopolymers, indicating that similar processing stabiliser packages may be used

Monitering van die emissies van vonkontstekingsenjins onder verskillende rykondisies en met verskillende brandstofformulerings

Tesis (M. Sc) -- Universiteit van Stellenbosch, 1997.Een kopie mikrofiche.Full text to be digitised and attached to bibliographic record

"Ska vi arbeta hårdast eller smartast?" : En kvalitativ studie med fokus på IT-företag i Växjö och deras arbete med processinnovationer

Titel: “Ska vi arbeta hårdast eller smartast?” – En kvalitativ studie med fokus på IT-företag i Växjö och deras arbete med processinnovationer.  Bakgrund: Företag arbetar dagligen i processer. Det blir väsentligt för företag att utveckla sina processer för att säkerställa att de bedriver sitt arbete på det mest effektiva arbetssättet - med fokus på att arbeta smartare snarare än hårdare. Processinnovationer innebär att vara innovativ med fokus på att förändra sina befintliga processer och dess arbetssätt för att säkerställa effektiva processer. Resultatet av processinnovationer kan exempelvis innebära minskade kostnader, tidsbesparing och ökat kundvärde. IT-branschen har visat sig vara den mest innovationsaktiva bransch i Sverige där processinnovationer var den mest förekommande.  Syfte och problemformulering: Syftet med studien är att skapa förståelse kring hur IT- företag i Växjö arbetar med processinnovationer. Studiens två problemformuleringar är: 1. Hur bedrivs processinnovationer på IT-företag i Växjö? 2. Vilka likheter respektive skillnader går att identifiera i processinnovationerna på IT-företag i Växjö?  Teori: Den teoretiska referensramen bygger på processinnovation med stöd av genomgång av innovation och processer. Dessutom görs en djupare redogörelse för centrala och essentiella delar inom arbetet med processinnovationer: öppenhet, samarbete, processkartläggning och IT-system vid processinnovationer.  Metod: Studien bygger på en fallstudiedesign med tre fall (tre IT-företag i Växjö). Den empiriska insamlingen bestod av totalt elva semistrukturerade intervjuer med representanter fördelat mellan studiens tre företag. Urvalet av respondenter gjordes via ett målstyrt urval och snöbollsurval för att säkerställa medverkande respondenter som hade inblick i företagens arbete med processinnovationer.  Slutsats: Resultatet av studien visar att samtliga företag arbetar tydligt och strukturerat med processinnovation. Vi har kunnat skapa en god förståelse samt kunskap om arbetssättet kring processinnovationer på IT-företag i Växjö. Studien har även identifierat likheter och skillnader kring företagens arbetssätt vid processinnovationer.