Recent years have seen an increasing interest in asymmetrical flow field-flow fractionation (AF4) as a method for the fractionation and characterization of macromolecules and colloidal particles. In ...this paper utilization of AF4 in food applications is reviewed. Instrumental considerations are discussed as well as which properties can be assessed by AF4 and adequate detection systems. Furthermore, published literature on analysis of food macromolecules with AF4 is critically reviewed.
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Neuronal and glial cell interaction is essential for synaptic homeostasis and may be affected in Alzheimer's disease (AD). We measured cerebrospinal fluid (CSF) neuronal and glia markers along the AD ...continuum, to reveal putative protective or harmful stage-dependent patterns of activation.
We included healthy controls (n = 36) and Aβ-positive (Aβ+) cases (as defined by pathological CSF amyloid beta 1-42 (Aβ42)) with either subjective cognitive decline (SCD, n = 19), mild cognitive impairment (MCI, n = 39), or AD dementia (n = 27). The following CSF markers were measured: a microglial activation marker-soluble triggering receptor expressed on myeloid cells 2 (sTREM2), a marker of microglial inflammatory reaction-monocyte chemoattractant protein-1 (MCP-1), two astroglial activation markers-chitinase-3-like protein 1 (YKL-40) and clusterin, a neuron-microglia communication marker-fractalkine, and the CSF AD biomarkers (Aβ42, phosphorylated tau (P-tau), total tau (T-tau)). Using ANOVA with planned comparisons, or Kruskal-Wallis tests with Dunn's pairwise comparisons, CSF levels were compared between clinical groups and between stages of biomarker severity using CSF biomarkers for classification based on amyloid pathology (A), tau pathology (T), and neurodegeneration (N) giving rise to the A/T/N score.
Compared to healthy controls, sTREM2 was increased in SCD (p < .01), MCI (p < .05), and AD dementia cases (p < .001) and increased in AD dementia compared to MCI cases (p < .05). MCP-1 was increased in MCI (p < .05) and AD dementia compared to both healthy controls (p < .001) and SCD cases (p < .01). YKL-40 was increased in dementia compared to healthy controls (p < .01) and MCI (p < .05). All of the CSF activation markers were increased in subjects with pathological CSF T-tau (A+T-N+ and A+T+N+), compared to subjects without neurodegeneration (A-T-N- and A+T-N-).
Microglial activation as indicated by increased sTREM2 is present already at the preclinical SCD stage; increased MCP-1 and astroglial activation markers (YKL-40 and clusterin) were noted only at the MCI and AD dementia stages, respectively, and in Aβ+ cases (A+) with pathological T-tau (N+). Possible different effects of early and later glial activation need to be explored.
Objectives
To reveal distinct longitudinal trajectories in episodic memory over 15 years and to identify demographic, lifestyle, health‐related, and genetic predictors of stability or decline.
Design
...Prospective cohort study.
Setting
The Betula Project, Umeå, Sweden.
Participants
One thousand nine hundred fifty‐four healthy participants aged 35 to 85 at baseline.
Measurements
Memory was assessed according to validated episodic memory tasks in participants from a large population‐based sample. Data were analyzed using a random‐effects pattern‐mixture model that considered the effect of attrition over two to four longitudinal sessions. Logistic regression was used to determine significant predictors of stability or decline relative to average change in episodic memory.
Results
Of 1,558 participants with two or more test sessions, 18% were classified as maintainers and 13% as decliners, and 68% showed age‐typical average change. More educated and more physically active participants, women, and those living with someone were more likely to be classified as maintainers, as were carriers of the met allele of the catechol‐O‐methyltransferase gene. Less educated participants, those not active in the labor force, and men were more likely to be classified as decliners, and the apolipoprotein E ɛ4 allele was more frequent in decliners.
Conclusion
Quantitative, attrition‐corrected assessment of longitudinal changes in memory can reveal substantial heterogeneity in aging trajectories, and genetic and lifestyle factors predict such heterogeneity.
Climate policy objectives require zero emissions across all sectors including steelmaking. The fundamental process changes needed for reaching this target are yet relatively unexplored. In this ...paper, we propose and assess a potential design for a fossil-free steelmaking process based on direct reduction of iron ore with hydrogen. We show that hydrogen direct reduction steelmaking needs 3.48 MWh of electricity per tonne of liquid steel, mainly for the electrolyser hydrogen production. If renewable electricity is used the process will have essentially zero emissions. Total production costs are in the range of 361–640 EUR per tonne of steel, and are highly sensitive to the electricity price and the amount of scrap used. Hydrogen direct reduction becomes cost competitive with an integrated steel plant at a carbon price of 34–68 EUR per tonne CO2 and electricity costs of 40 EUR/MWh. A key feature of the process is flexibility in production and electricity demand, which allows for grid balancing through storage of hydrogen and hot-briquetted iron, or variations in the share of scrap used.
•A process design for hydrogen direct reduction (H-DR) steelmaking is proposed.•3.48 MWh electricity are consumed per ton of steel product.•H-DR emits only 2.8% of blast furnace CO2.•Competitive production cost at low electricity and moderate carbon prices.•High flexibility due to hydrogen and HBI storage, and varying scrap charge.
Designing Biobased Recyclable Polymers for Plastics Hatti-Kaul, Rajni; Nilsson, Lars J.; Zhang, Baozhong ...
Trends in biotechnology (Regular ed.),
January 2020, 2020-Jan, 2020-01-00, 20200101, 2020, Letnik:
38, Številka:
1
Journal Article
Recenzirano
Several concurrent developments are shaping the future of plastics. A transition to a sustainable plastics system requires not only a shift to fossil-free feedstock and energy to produce the ...carbon-neutral building blocks for polymers used in plastics, but also a rational design of the polymers with both desired material properties for functionality and features facilitating their recyclability. Biotechnology has an important role in producing polymer building blocks from renewable feedstocks, and also shows potential for recycling of polymers. Here, we present strategies for improving the performance and recyclability of the polymers, for enhancing degradability to monomers, and for improving chemical recyclability by designing polymers with different chemical functionalities.
Rational polymer design is important for desired functionality and recyclability.Increasing the glass transition temperature is an effective strategy for enhancing the performance and recyclability of biobased polymers.Selective polymer depolymerization and repolymerization of monomers offers an important route to plastic recycling.Microbial cells and enzymes constitute important tools for the production as well as recycling of polymers.Feedstock sustainability is a concern and CO2 will become an important alternative to biomass for fossil-free polymers.
• Nitrogen (N) availability is known to influence ectomycorrhizal fungal components, such as fungal community composition, biomass of root tips and production of mycelia, but effects have never been ...demonstrated within the same forest. • We measured concurrently the abundance of ectomycorrhizal root tips and the production of external mycelia, and explored the changes in the ectomycorrhizal community composition, across a stand‐scale N deposition gradient (from 27 to 43 kg N ha−1 yr−1) at the edge of a spruce forest. The N status was affected along the gradient as shown by a range of N availability indices. • Ectomycorrhizal root tip abundance and mycelial production decreased five and 10‐fold, respectively, with increasing N deposition. In addition, the ectomycorrhizal fungal community changed and the species richness decreased. The changes were correlated with the measured indices of N status, in particular N deposition and N leaching. • The relationship between the altered ectomycorrhizal community, root tip abundance and mycelial production is discussed in the context of the N parameters. We suggest that increased N deposition to forests will cause large changes in ectomycorrhizal fungal community structure and functioning, which, in turn, may result in reduced N uptake by roots and fungi, and increased losses of N by leaching.
Abstract Introduction The objective was to examine whether subjective memory impairment (SMI) predicts all-cause dementia or Alzheimer's disease (AD) in a population-based study with long-term ...follow-up (median = 10 years). Methods A total of 2043 initially dementia-free participants (≥ 60 years) made three memory ratings (“compared with others”, “compared with five years ago”, and “complaints from family/friends”) at baseline. During follow-up, 372 participants developed dementia (208 with AD). Results Cox regression revealed that subjective memory impairment ratings predicted all-cause dementia in models adjusting for age and sex (hazard ratio or HR from 2.04 to 3.94), with even higher values for AD (HR from 2.29 to 5.74). The result persisted in models including other covariates, including baseline episodic memory performance, and in analyses restricted to participants with long time to dementia diagnosis (≥ 5 years). Discussion The findings underscore the usefulness of subjective memory assessment in combination with other factors in identifying individuals at risk for developing dementia.
Exposure to ambient air pollution is suspected to cause cognitive effects, but a prospective cohort is needed to study exposure to air pollution at the home address and the incidence of dementia.
We ...aimed to assess the association between long-term exposure to traffic-related air pollution and dementia incidence in a major city in northern Sweden.
Data on dementia incidence over a 15-year period were obtained from the longitudinal Betula study. Traffic air pollution exposure was assessed using a land-use regression model with a spatial resolution of 50 m × 50 m. Annual mean nitrogen oxide levels at the residential address of the participants at baseline (the start of follow-up) were used as markers for long-term exposure to air pollution.
Out of 1,806 participants at baseline, 191 were diagnosed with Alzheimer's disease during follow-up, and 111 were diagnosed with vascular dementia. Participants in the group with the highest exposure were more likely than those in the group with the lowest exposure to be diagnosed with dementia (Alzheimer's disease or vascular dementia), with a hazard ratio (HR) of 1.43 (95% CI: 0.998, 2.05 for the highest vs. the lowest quartile). The estimates were similar for Alzheimer's disease (HR 1.38) and vascular dementia (HR 1.47). The HR for dementia associated with the third quartile versus the lowest quartile was 1.48 (95% CI: 1.03, 2.11). A subanalysis that excluded a younger sample that had been retested after only 5 years of follow-up suggested stronger associations with exposure than were present in the full cohort (HR = 1.71; 95% CI: 1.08, 2.73 for the highest vs. the lowest quartile).
If the associations we observed are causal, then air pollution from traffic might be an important risk factor for vascular dementia and Alzheimer's disease.
To explore neural correlates of cognitive decline in aging, we used longitudinal behavioral data to identify two groups of older adults (n = 40) that differed with regard to whether their performance ...on tests of episodic memory remained stable or declined over a decade. Analysis of structural and diffusion tensor imaging (DTI) revealed a heterogeneous set of differences associated with cognitive decline. Manual tracing of hippocampal volume showed significant reduction in those older adults with a declining memory performance as did DTI-measured fractional anisotropy in the anterior corpus callosum. Functional magnetic resonance imaging during incidental episodic encoding revealed increased activation in left prefrontal cortex for both groups and additional right prefrontal activation for the elderly subjects with the greatest decline in memory performance. Moreover, mean DTI measures in the anterior corpus callosum correlated negatively with activation in right prefrontal cortex. These results demonstrate that cognitive decline is associated with differences in the structure as well as function of the aging brain, and suggest that increased activation is either caused by structural disruption or is a compensatory response to such disruption.
Cross-sectional estimates of age-related changes in brain structure and function were compared with 6-y longitudinal estimates. The results indicated increased sensitivity of the longitudinal ...approach as well as qualitative differences. Critically, the cross-sectional analyses were suggestive of age-related frontal overrecruitment, whereas the longitudinal analyses revealed frontal underrecruitment with advancing age. The cross-sectional observation of overrecruitment reflected a select elderly sample. However, when followed over time, this sample showed reduced frontal recruitment. These findings dispute inferences of true age changes on the basis of age differences, hence challenging some contemporary models of neurocognitive aging, and demonstrate age-related decline in frontal brain volume as well as functional response.
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