Optimization and evaluation of a sheathless capillary electrophoresis-electrospray ionization mass spectrometry platform for peptide analysis: comparison to liquid chromatography-electrospray ionization mass spectrometry

In this study we have evaluated the suitability of a sheathless capillary electrophoresis-electrospray ionization mass spectrometry (CE-ESI-MS) interface with a porous tip as the nanospray emitter for use in peptide analysis. A positively charged capillary coating and 0.1% formic acid as background electrolyte were used for separation upstream from mass spectrometry characterization. The influence of the distance between emitter tip and MS inlet, ESI voltage applied, and of the electroosmotic flow (EOF) on electrospray performance and efficiency of the system was investigated in detail. Under optimized conditions, less than 30 amol of a model peptide (angiotensin I) was required for a detection in the base peak electropherogram and positive identification via tandem MS. Three different cationic capillary coatings were investigated for stability, resolution, and EOF and were found to enable reproducible separations by CE-ESI-MS. After optimizing MS settings, the effectiveness of the CE-ESI-MS method developed was compared with a state-of-the-art nano-liquid chromatography (LC)-ESI-MS method by analyzing Arg-C-digested rat testis linker histones with both systems. With comparable amounts of sample applied, the number of identified peptides increased by more than 60% when using CE-ESI-MS. We found that low molecular mass peptides (below 1400 Da) were preferentially identified by CE-ESI-MS, since this group of peptides poorly interacted with the reversed-phase material in the nano-LC system. Finally, total analysis time in LC-ESI-MS for three runs including equilibration was nearly 4 times longer than that of CE-ESI-MS: 246 versus 66 min.     

Progressively Type-II censored competing risks data from Lomax distributions

A competing risks model based on Lomax distributions is considered under progressive Type-II censoring. Maximum likelihood estimates for the distribution parameters are established. Moreover, the expected Fisher information matrix is computed and optimal Fisher information based censoring plans are discussed. In particular, it turns out that the optimal censoring scheme depends on the particular parametrization of the Lomax distributions.     

Sense-making strategies in explorative intelligence analysis of network evolutions

Visualising how social networks evolve is important in intelligence analysis in order to detect and monitor issues, such as emerging crime patterns or rapidly growing groups of offenders. It remains an open research question how this type of information should be presented for visual exploration. To get a sense of how users work with different types of visualisations, we evaluate a matrix and a node-link diagram in a controlled thinking aloud study. We describe the sense-making strategies that users adopted during explorative and realistic tasks. Thereby, we focus on the user behaviour in switching between the two visualisations and propose a set of nine strategies. Based on a qualitative and quantitative content analysis we show which visualisation supports which strategy better. We find that the two visualisations clearly support intelligence tasks and that for some tasks the combined use is more advantageous than the use of an individual visualisation.     

The Perspective of Safety Engineers on Safety Climate

The aim of this study was to investigate safety climate and how it relates to the safety performance of employees from the perspective of safety engineers. Using Griffin and Neal's (2000) safety climate model as a theoretical basis, we hypothesized that the organizational safety climate is a higher‐order construct that relates to the safety compliance of employees and their safety participation via the mediating roles of safety knowledge and safety motivation. Hypotheses were tested among 236 safety engineers working in the wood and metal‐processing industries in Austria. Structural equation modeling (SEM) analysis showed that safety climate is a higher‐order construct comprising manager values, safety communication, safety practices, safety training, and safety equipment. Moreover, from the perspective of safety engineers, the safety climate of the organizations was related to employee safety motivation, which in turn related to their safety compliance and safety participation. In contrast to our assumptions, the safety knowledge of employees was, in the view of safety engineers, neither related to employee safety compliance nor to their safety participation. Multigroup analysis revealed no differences between internally and externally employed safety engineers for these relations. Thus, although the safety climate model was generally confirmed from an engineer's perspective, engineers rated motivational aspects of safety climate is more important compared to knowledge aspects.     

Do children profit from looking beyond looks? From similarity-based to cue abstraction processes in multiple-cue judgment.

The authors investigated the ability of 9- to 11-year-olds and of adults to use similarity-based and rule-based processes as a function of task characteristics in a task that can be considered either a categorization task or a multiple-cue judgment task, depending on the nature of the criterion (binary vs. continuous). Both children and adults relied on similarity-based processes in the categorization task. However, adults relied on cue abstraction in the multiple-cue judgment task, whereas the majority of children continued to rely on similarity-based processes. Reliance on cue abstraction resulted in better judgments for adults but not for children in the multiple-cue judgment task. This suggests that 9- to 11-year-olds may have defaulted to similarity-based processes because they were not able to employ a cue abstraction process efficiently. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Geographic origin of meat—elements of an analytical approach to its authentication

This review article discusses recent analytical developments with respect to the determination of the geographic origin of raw meat. The main emphasis is laid on lamb, beef and poultry. So far, some methods have shown quite promising potential (e.g. stable isotope ratios, trace elements), others have remained unsatisfactory in their discriminating power to authenticate the geographic origin of meat (e.g. microbiological profile, sensory traits, volatile compounds). Other methods (e.g. animal genotype, gross chemical composition) could be auxiliary criteria as they help to determine related indicators such as feeding or housing conditions but not directly the origin. The complexity of this question is large. An integrated approach simultaneously addressing various species and production characteristics such as environment, animal husbandry conditions, breed, feeding and drinking water has to be developed. Strategies have to be different for global and micro-regional scales.     

Fitting finite mixtures of generalized linear regressions in R

R package flexmix provides flexible modelling of finite mixtures of regression models using the EM algorithm. Several new features of the software such as fixed and nested varying effects for mixtures of generalized linear models and multinomial regression for a priori probabilities given concomitant variables are introduced. The use of the software in addition to model selection is demonstrated on a logistic regression example.     

Semantic Web search based on ontological conjunctive queries

Many experts predict that the next huge step forward in Web information technology will be achieved by adding semantics to Web data, and will possibly consist of (some form of) the Semantic Web. In this paper, we present a novel approach to Semantic Web search, called Serene, which allows for a semantic processing of Web search queries, and for evaluating complex Web search queries that involve reasoning over the Web. More specifically, we first add ontological structure and semantics to Web pages, which then allows for both attaching a meaning to Web search queries and Web pages, and for formulating and processing ontology-based complex Web search queries (i.e., conjunctive queries) that involve reasoning over the Web. Here, we assume the existence of an underlying ontology (in a lightweight ontology language) relative to which Web pages are annotated and Web search queries are formulated. Depending on whether we use a general or a specialized ontology, we thus obtain a general or a vertical Semantic Web search interface, respectively. That is, we are actually mapping the Web into an ontological knowledge base, which then allows for Semantic Web search relative to the underlying ontology. The latter is then realized by reduction to standard Web search on standard Web pages and logically completed ontological annotations. That is, standard Web search engines are used as the main inference motor for ontology-based Semantic Web search. We develop the formal model behind this approach and also provide an implementation in desktop search. Furthermore, we report on extensive experiments, including an implemented Semantic Web search on the Internet Movie Database.     

Could Lower Testosterone in Older Men Explain Higher COVID-19 Morbidity and Mortalities?

The health scourge imposed on humanity by the COVID-19 pandemic seems not to recede. This fact warrants refined and novel ideas analyzing different aspects of the illness. One such aspect is related to the observation that most COVID-19 casualties were older males, a tendency also noticed in the epidemics of SARS-CoV in 2003 and the Middle East respiratory syndrome in 2012. This gender-related difference in the COVID-19 death toll might be directly involved with testosterone (TEST) and its plasmatic concentration in men. TEST has been demonstrated to provide men with anti-inflammatory and immunological advantages. As the plasmatic concentration of this androgen decreases with age, the health benefit it confers also diminishes. Low plasmatic levels of TEST can be determinant in the infection’s outcome and might be related to a dysfunctional cell Ca²⁺ homeostasis. Not only does TEST modulate the activity of diverse proteins that regulate cellular calcium concentrations, but these proteins have also been proven to be necessary for the replication of many viruses. Therefore, we discuss herein how TEST regulates different Ca²⁺-handling proteins in healthy tissues and propose how low TEST concentrations might facilitate the replication of the SARS-CoV-2 virus through the lack of modulation of the mechanisms that regulate intracellular Ca²⁺ concentrations.