Biochar has triggered a black gold rush in environmental studies as a carbon-rich material with well-developed porous structure and tunable functionality. While much attention has been placed on its ...apparent ability to store carbon in the ground, immobilize soil pollutants, and improve soil fertility, its temporally evolving in situ performance in these roles must not be overlooked. After field application, various environmental factors, such as temperature variations, precipitation events and microbial activities, can lead to its fragmentation, dissolution, and oxidation, thus causing drastic changes to the physicochemical properties. Direct monitoring of biochar-amended soils can provide good evidence of its temporal evolution, but this requires long-term field trials. Various artificial aging methods, such as chemical oxidation, wet-dry cycling and mineral modification, have therefore been designed to mimic natural aging mechanisms. Here we evaluate the science of biochar aging, critically summarize aging-induced changes to biochar properties, and offer a state-of-the-art for artificial aging simulation approaches. In addition, the implications of biochar aging are also considered regarding its potential development and deployment as a soil amendment. We suggest that for improved simulation and prediction, artificial aging methods must shift from qualitative to quantitative approaches. Furthermore, artificial preaging may serve to synthesize engineered biochars for green and sustainable environmental applications.
Brain-derived neurotrophic factor (BDNF) Val66Met polymorphism has previously been implicated in Alzheimer's disease (AD)arelated cognitive impairment. We aimed to determine the relationship between ...BDNF Val66Met and beta-amyloid (AI2) on cognitive decline, hippocampal atrophy, and AI2 accumulation over 36 months in 165 healthy adults enrolled in the Australian Imaging, Biomarkers and Lifestyle study. In healthy adults with high AI2, Met carriers showed significant and moderate-to-large declines in episodic memory, executive function, and language, and greater hippocampal atrophy over 36 months, compared with Val/Val homozygotes. BDNF Val66Met was not found to be related to rates of change in cognition or hippocampal volume in healthy adults with low AI2. BDNF Val66Met did not relate to the amount of AI2 or to the rate of AI2 accumulation in either group. High AI2 levels coupled with Met carriage may be useful prognostic markers of accelerated cognitive decline and hippocampal degeneration in individuals in the preclinical stage of AD.
A role of amyloid I2 (AI2) peptide aggregation and deposition in Alzheimer's disease (AD) pathogenesis is widely accepted. Significantly, abnormalities induced by aggregated AI2 have been linked to ...synaptic and neuritic degeneration, consistent with the adying-backa pattern of degeneration that characterizes neurons affected in AD. However, molecular mechanisms underlying the toxic effect of aggregated AI2 remain elusive. In the last 2 decades, a variety of aggregated AI2 species have been identified and their toxic properties demonstrated in diverse experimental systems. Concurrently, specific AI2 assemblies have been shown to interact and misregulate a growing number of molecular effectors with diverse physiological functions. Such pleiotropic effects of aggregated AI2 posit a mayor challenge for the identification of the most cardinal AI2 effectors relevant to AD pathology. In this review, we discuss recent experimental evidence implicating amyloid I2 precursor protein (APP) as a molecular target for toxic AI2 assemblies. Based on a significant body of pathologic observations and experimental evidence, we propose a novel pathologic feed-forward mechanism linking AI2 aggregation to abnormalities in APP processing and function, which in turn would trigger the progressive loss of neuronal connectivity observed early in AD.
Objective: Hyperkinetic perseveration (HKP) refers to perseverative repetition of rudimentary motor output. Although HKP is known to be associated with brain injuries and certain neurodegenerative ...disorders (primarily those involving the frontal lobes and the basal ganglia), an increased tendency to exhibit HKP is also commonly associated with apparently normal aging (i.e., in the absence of known neuropathology). The purpose of the present study was to examine anomalies in brain functioning associated with HKP tendencies in a non-injured brain.
Substantial individual differences exist in the magnitude of the cognitive decline associated with normal aging. Potential contributors to this intersubject variability include white matter ...hyperintensities (WMH) and preclinical Alzheimera2s disease, evident as increased brain amyloid. This study examined whether older individuals with minimal evidence of WMH and/or brain amyloid-beta (seen on positron emission tomography with the Pittsburgh compound B radiotraceraPiB) still showed significant cognitive decrements compared to the young. Older individuals, conservatively screened for normal range performance on an extensive neuropsychological battery, underwent structural magnetic resonance imaging (MRI) and PiB scans and performed tests of information processing speed, working memory and inhibitory function. The elderly were divided into PiB(+) and PiB(a) groups based on radiotracer retention. There were no significant differences in cognitive performance between PiB(+) and PiB(a) elderly. However, both PiB groups performed significantly worse than did the young on cognitive testing. WMH burden in the same individuals was quantified by consensus ratings using a 10 point scale with a median split defining two groups, WMH(+) and WMH(a). There were no differences in cognitive performance between WMH(+) and WMH(a) individuals, but both WMH groups performed significantly worse than did the young. Older participants who were both PiB(a) and WMH(a) also performed significantly worse than did the young in all three cognitive domains. The present results suggest that normal-elderly individuals whose brain scans show minimal evidence of amyloid deposition or WMH, still demonstrate a major decrement in comparison to younger persons on measures of processing resources and inhibitory efficiency.
The weathering performance of polymeric backsheets is most accurately assessed by outdoor exposure to natural weathering and examination of their performance characteristics by observing changes in ...properties. The main drawback of natural weathering is the long exposure time. Therefore, also existing qualification tests for photovoltaic (PV) components suggest accelerated artificial aging tests. This should lead to similar materials degradation as long-term outdoor exposures cause. However, it is necessary to establish connections between field performance of polymer products and accelerated materials durability testing in order to better predict the service life of a polymer product. Therefore, the main focus of this work was to evaluate the effect of natural and artificial aging on multilayer backsheet films for PV modules. For this reason, different backsheet films were naturally and artificially aged. Subsequently the optical, chemical, mechanical and thermal properties were characterized. In general, only some changes in properties after up to 3000 h of accelerated aging can be correlated with natural weathering for 2.5 years. The degradation mechanism of the polymeric part during natural weathering has to be considered when trying to simulate natural aging conditions in order to choose the right parameters for artificial aging. Thus, the right test design for artificial aging tests is highly important, as well as the consideration of the degradation mechanisms when trying to simulate natural aging conditions.
•Xenon aging didn't provoke same changes in optical properties as natural weathering.•UV-fluorescence aging with standardized parameters was the most harmful test.•The used artificial aging tests (ISO4892) only partially simulate natural aging.•Different microclimatic conditions were found for outdoor and indoor weathering.
Summary
Female reproductive capacity declines dramatically in the fourth decade of life as a result of an age‐related decrease in oocyte quality and quantity. The primary causes of reproductive aging ...and the molecular factors responsible for decreased oocyte quality remain elusive. Here, we show that aging of the female germ line is accompanied by mitochondrial dysfunction associated with decreased oxidative phosphorylation and reduced Adenosine tri‐phosphate (ATP) level. Diminished expression of the enzymes responsible for CoQ production, Pdss2 and Coq6, was observed in oocytes of older females in both mouse and human. The age‐related decline in oocyte quality and quantity could be reversed by the administration of CoQ10. Oocyte‐specific disruption of Pdss2 recapitulated many of the mitochondrial and reproductive phenotypes observed in the old females including reduced ATP production and increased meiotic spindle abnormalities, resulting in infertility. Ovarian reserve in the oocyte‐specific Pdss2‐deficient animals was diminished, leading to premature ovarian failure which could be prevented by maternal dietary administration of CoQ10. We conclude that impaired mitochondrial performance created by suboptimal CoQ10 availability can drive age‐associated oocyte deficits causing infertility.
Biological aging involves an interplay of conserved and targetable molecular mechanisms, summarized as the hallmarks of aging. Metformin, a biguanide that combats age-related disorders and improves ...health span, is the first drug to be tested for its age-targeting effects in the large clinical trial—TAME (targeting aging by metformin). This review focuses on metformin’s mechanisms in attenuating hallmarks of aging and their interconnectivity, by improving nutrient sensing, enhancing autophagy and intercellular communication, protecting against macromolecular damage, delaying stem cell aging, modulating mitochondrial function, regulating transcription, and lowering telomere attrition and senescence. These characteristics make metformin an attractive gerotherapeutic to translate to human trials.
Metformin is the first drug to be tested for its age-targeting effects in a large clinical trial. In this perspective, Kulkarni et al. review how metformin acts on its primary and secondary targets to attenuate the hallmarks of aging, highlighting its utility as an effective gerotherapeutic intervention.
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Cellular senescence is now recognized as one of the nine hallmarks of ageing. Recent data show the involvement of senescent cells in tissue ageing and some age-related diseases. Skin ...represents an ideal model for the study of ageing. Indeed, skin ageing varies between individuals depending on their chronological age but also on their exposure to various exogenous factors (mainly ultraviolet rays). If senescence traits can be detected with ageing in the skin, the senescent phenotype varies among the various skin cell types. Moreover, the origin of cellular senescence in the skin is still unknown, and multiple origins are possible. This reflects the mosaic of skin ageing. Senescent cells can interfere with their microenvironment, either via the direct secretion of factors (the senescence-associated secretory phenotype) or via other methods of communication, such as extracellular vesicles. Knowledge regarding the impact of cellular senescence on skin ageing could be integrated into dermatology research, especially to limit the appearance of senescent cells after photo(chemo)therapy or in age-related skin diseases. Therapeutic approaches include the clearance of senescent cells via the use of senolytics or via the cooperation with the immune system.
The rare variant A673T in the amyloid-I2 precursor protein (APP) gene has been shown to reduce the risk of cognitive impairment. We genotyped the variant in 8721 Asian individuals comprising 552 with ...Alzheimer's disease and vascular dementia, 790 with Parkinson's disease, and 7379 controls. The A673T variant was absent in all of the subjects. Our finding suggests that the A673T protective variant is not relevant in our Asian population. Studies in other ethnic populations would clarify whether this variant is specific to specific races/ethnicities.
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