In vitro transition of Schistocephalus solidus (Cestoda) from coracidium to procercoid and from procercoid to plerocercoid

With the present study, a culture system for successive life-cycle stages of the tapeworm Schistocephalus solidus was developed and this report documents for the first time, cultivation of the procercoid stage of S. solidus from eggs. Additionally we have transformed procercoids dissected from experimentally infected copepods and cultured procercoids into the early plerocercoid stage in vitro. Observations in the culture suggest that the coracidia can interact with their external environment and need no host specific stimuli, except for the components in the culture medium, for activation and hatching from the embryophore. Increasing the culture medium pH from 7.3 to 8.0 improved escape rates and frequencies of hook contractions, suggesting that the oncosphere may recognize and respond to environmental conditions along the host intestine. Procercoids in the culture did not stop growing indicating that conditions within the copepod may be important to limit growth and to induce transformation to plerocercoids. When procercoids are dissected from copepods and transferred to the culture, the outer tegument layers and cercomer starts to loosen. Comparison of the lectin staining of the loosened outer tegument layers and cercomer in procercoids dissected from copepods confirms that transitions of both, the oncosphere to procercoid and procercoid to plerocercoids, has taken place in the in vitro cultures

Task based profiles of language impairment in Parkinson’s Disease

This study aimed to add to our understanding of language impairment in people with Parkinson's Disease (PwPD). Language difficulties are increasingly reported in PD. However, there are contradictory reports on how they relate to motor and cognitive impairment. In addition, the link between various language deficits or the same deficits across task modalities is not well understood. This lack of understanding impacts on clinicians’ ability to assess and effectively treat language impairment in PD. Our study therefore aimed to investigate language performance across a number of task structures and correlate this performance with cognitive skills, as well as motor and speech performance. The study included 22 German speaking PwPD and 22 matched healthy control participants. 18 participants in each group were cognitively healthy and four had mild cognitive impairment. They performed a number of executive function and language tasks of different complexity and structure. The linguistic investigation focused on grammatical accuracy and complexity, linguistic content as well as articulatory features. There were few cognitive differences between the two groups, with only set-shifting as an executive function being significantly reduced in PwPD, but grammatical error rate was higher in PwPD than in their healthy controls across all language tasks. This was linked to set shifting skills but only for the complex grammar condition, not for more naturalistic language tasks. Furthermore, there was no correlation of language performance across the task levels, i.e. error rates in the structured task did not predict naturalistic performance. Motor and dysarthria severity could not predict language impairment either. This study confirms the presence of language problems in PwPD in the absence of global cognitive impairment or only MCI, and at the same time establishes a task based relationship between the two skills. From a clinical perspective the data indicate that structured tests are unable to accurately predict naturalistic language performance, highlighting the need for functional assessments rather than relying on fast scoring structured tests, at least at early disease stages. In addition, the impact of the individual language difficulties needs to be explored to establish appropriate and effective treatment pathways

Lower cognitive baseline scores predict cognitive training success after 6 months in healthy older adults: Results of an online RCT

Background: Identifying predictors for general cognitive training (GCT) success in healthy older adults has many potential uses, including aiding intervention and improving individual dementia risk prediction, which are of high importance in health care. However, the factors that predict training improvements and the temporal course of predictors (eg, do the same prognostic factors predict training success after a short training period, such as 6 weeks, as well as after a longer training period, such as 6 months?) are largely unknown. Methods: Data (N = 4,184 healthy older individuals) from two arms (GCT vs. control) of a three-arm randomized controlled trial were reanalyzed to investigate predictors of GCT success in five cognitive tasks (grammatical reasoning, spatial working memory, digit vigilance, paired association learning, and verbal learning) at three time points (after 6 weeks, 3 months, and 6 months of training). Possible investigated predictors were sociodemographic variables, depressive symptoms, number of training sessions, cognitive baseline values, and all interaction terms (group*predictor). Results: Being female was predictive for improvement in grammatical reasoning at 6 weeks in the GCT group, and lower cognitive baseline scores were predictive for improvement in spatial working memory and verbal learning at 6 months. Conclusion: Our data indicate that predictors seem to change over time; remarkably, lower baseline performance at study entry is only a significant predictor at 6 months training. Possible reasons for these results are discussed in relation to the compensation hypothesis. J Am Geriatr Soc 68:-, 2020.This article is freely available via Open Access. Click on the Publisher URL to access it via the publisher's site.Alzheimer's Society UKpublished version, accepted version (12 month embargo), submitted versio

Optical and electronic properties of amorphous silicon dioxide by single and double electron spectroscopy

Abstract An investigation of the optical and electronic properties of amorphous silicon dioxide by means of a combination of reflection electron energy loss spectroscopy (REELS) and secondary electron–electron energy loss coincidence spectroscopy (SE2ELCS) is presented. Optical constants for a-SiO2 were extracted from the REELS measurements and a band gap of 9.1 eV was determined by deconvolution of multiple scattering and fitting the differential inverse inelastic mean free path with a model energy loss function (ELF). The coincidence measurements allow to determine the surface barrier height and the electron affinity was determined to be 0.8 eV. Furthermore, the coincidence measurements show that even in the case of an insulator, plasmon decay is the main mechanism for generation of secondary electrons

Transcriptome profiling of immune tissues reveals habitat-specific gene expression between lake and river sticklebacks

The observation of habitat-specific phenotypes suggests the action of natural selection. The three-spined stickleback (Gasterosteus aculeatus) has repeatedly colonized and adapted to diverse freshwater habitats across the northern hemisphere since the last glaciation, while giving rise to recurring phenotypes associated with specific habitats. Parapatric lake and river populations of sticklebacks harbour distinct parasite communities, a factor proposed to contribute to adaptive differentiation between these ecotypes. However, little is known about the transcriptional response to the distinct parasite pressure of those fish in a natural setting. Here, we sampled wild-caught sticklebacks across four geographical locations from lake and river habitats differing in their parasite load. We compared gene expression profiles between lake and river populations using 77 whole-transcriptome libraries from two immune-relevant tissues, the head kidney and the spleen. Differential expression analyses revealed 139 genes with habitat-specific expression patterns across the sampled population pairs. Among the 139 differentially expressed genes, eight are annotated with an immune function and 42 have been identified as differentially expressed in previous experimental studies in which fish have been immune challenged. Together, these findings reinforce the hypothesis that parasites contribute to adaptation of sticklebacks in lake and river habitats

Genomics of Divergence along a Continuum of Parapatric Population Differentiation

MM received funding from the Max Planck innovation funds for this project. PGDF was supported by a Marie Curie European Reintegration Grant (proposal nr 270891). CE was supported by German Science Foundation grants (DFG, EI 841/4-1 and EI 841/6-1)

Surface-Energy Control and Characterization of Nanoparticle Coatings

Accurate and reproducible measurement of the structure and properties of high-value nanoparticles is extremely important for their commercialization. A significant proportion of engineered nanoparticle systems consist of some form of nominally core\u2013shell structure, whether by design or unintentionally. Often, these do not form an ideal core\u2013shell structure, with typical deviations including polydispersity of the core or shell, uneven or incomplete shells, noncentral cores, and others. Such systems may be created with or without intent, and in either case an understanding of the conditions for formation of such particles is desirable. Precise determination of the structure, composition, size, and shell thickness of such particles can prove challenging without the use of a suitable range of characterization techniques. Here, the authors present two such polymer core\u2013shell nanoparticle systems, consisting of polytetrafluoroethylene cores coated with a range of thicknesses of either polymethylmethacrylate or polystyrene. By consideration of surface energy, it is shown that these particles are expected to possess distinctly differing coating structures, with the polystyrene coating being incomplete. A comprehensive characterization of these systems is demonstrated, using a selection of complementary techniques including scanning electron microscopy, scanning transmission electron microscopy, thermogravimetric analysis, dynamic light scattering, differential centrifugal sedimentation, and X-ray photoelectron spectroscopy. By combining the results provided by these techniques, it is possible to achieve superior characterization and understanding of the particle structure than could be obtained by considering results separately