Altered auditory processes pattern predicts cognitive decline in older adults: different modalities with aging

BackgroundCohort studies have shown that older adults with hearing impairment as assessed by self-report or behavioral measures are at higher risk of developing dementia many years later. A fine-grained examination of auditory processing holds promise for more effective screening of older adults at risk of cognitive decline. The auditory mismatch negativity (MMN) measure enables one to gain insights into the neurobiological substrate of central auditory processing. We hypothesized that older adults showing compromised indexes of MMN at baseline would exhibit cognitive decline at the one-year follow-up.MethodsWe performed cognitive evaluations with the Repeatable Battery for the Assessment of Neuropsychological Status (RBANS; Form A and Form B) in 108 community-dwelling older adults and acquired EEG via the classic passive auditory oddball paradigm at baseline and 12-month follow-up.ResultsThe results showed that young-old adults with future cognitive decline showed a decrease in MMN peak amplitude, accompanied by a forward-shifting latency, whereas in older adults it showed a delay in MMN latency, and unchanged MMN peak amplitude at midline electrodes (Fz, FCz and Cz). Furthermore, the peak amplitude of the MMN decreases with age in older adults aged 70–80 years rather than 60–70 years or > 80 years.ConclusionThe altered MMN model exists in different aging stages and it’s a promising electrophysiological predictor of cognitive decline in older adults. In addition, further research is needed to determine the neural mechanisms and potential implications of the accelerated decline in MMN in older adults

Paleolimnological environments and organic accumulation of the Nenjiang formation in the southeastern Songliao basin, China

Thick layers of dark lacustrine mudstone in the Nenjiang Formation record the evolution of local depositional environments in the Songliao Basin. This evolution in lake water is accurately reflected in variations in trace element compositions in sedimentary rocks. In this study, element geochemistry and clay mineralogy in successive cores were investigated to have a closer insight into the paleolimnological environment and organic accumulation during the Nenjiang epoch. Analysis of the contents of Mn, Ca and Ti, as well as Rb/Sr and Sr/Cu revealed that paleoclimate cycled between warm and humid to semi-arid and hot. The study of Sr/Ba ratios, clay minerals and stable isotopes indicated that both high and low salinity existed in two stages, and that high salinity in Member 1 of the Nenjiang Formation is likely correlated with transgressive events. Analysis of the ratios of V/V + Ni, Ni/V and Th/U suggested that the paleolimnological environment was reducing. The investigation of paleotemperature demonstrated that the Nenjiang Formation was deposited in a warm water environment, analysis of carbon and oxygen isotopes revealed its deposition in open paleolake. High paleoproductivity and salinity as well as redox potentials represent the most favorable environment for oil shale enrichment.</p

Hearing aids utilization, effect factors, and its benefit in the association between hearing and cognition decline: A longitudinal follow-up in Shanghai, China

Objective: To explore the rate and effect factors of hearing aids utilization in Chinese community elderly people, as well as the benefit role of hearing aids in the association of hearing loss and cognition decline. Methods: This study was designed based on a longitudinal 7-years follow-up conducted in Shanghai (China). Demographic characteristics, hearing level, hearing aids utilization and Activities of Daily Living (ADL) of participants were collected by Unified Needs Assessment Form for Elderly Care Questionnaire. Cognition function was assessed by Mini-mental State Examination (MMSE) scale. Multivariate logistic regression and linear regression were used for statistical analysis. Results: Hearing aids utilization rate in Chinese community elderly people is below 10 %. Participants with older age (≥80 years old), higher education (7–12 years and >12 years), who can manage money more independently were more likely to use hearing aids (P < 0.05). Whether hearing aids are used or not, hearing level is significantly associated with cognition in elderly people, but participants with hearing aids showed a slower cognitive decline speed. Conclusion: Hearing aids utilization may slow down the cognition descent via assisting hearing in daily life, so strategies need to be concerned in order to protect hearing function in all elderly and improve the use of hearing aids in HL elderly

Environmental context for the terminal Ediacaran biomineralization of animals

"In terminal Ediacaran strata of South China, the onset of calcareous biomineralization is preserved in the paleontological transition from Conotubus to Cloudina in repetitious limestone facies of the Dengying Formation. Both fossils have similar size, funnel-in-funnel construction, and epibenthic lifestyle, but Cloudina is biomineralized, whereas Conotubus is not. To provide environmental context for this evolutionary milestone, we conducted a high-resolution elemental and stable isotope study of the richly fossiliferous Gaojiashan Member. Coincident with the first appearance of Cloudina is a significant positive carbonate carbon isotope excursion (up to + 6 parts per thousand) and an increase in the abundance and S-34 composition of pyrite. In contrast, delta S-34 values of carbonate-associated sulfate remain steady throughout the succession, resulting in anomalously large (>70 parts per thousand) sulfur isotope fractionations in the lower half of the member. The fractionation trend likely relates to changes in microbial communities, with sulfur disproportionation involved in the lower interval, whereas microbial sulfate reduction was the principal metabolic pathway in the upper. We speculate that the coupled paleontological and biogeochemical anomalies may have coincided with an increase in terrestrial weathering fluxes of sulfate, alkalinity, and nutrients to the depositional basin, which stimulated primary productivity, the spread of an oxygen minimum zone, and the development of euxinic conditions in subtidal and basinal environments. Enhanced production and burial of organic matter is thus directly connected to the carbon isotope anomaly, and likely promoted pyritization as the main taphonomic pathway for Conotubus and other soft-bodied Ediacara biotas. Our studies suggest that the Ediacaran confluence of ecological pressures from predation and environmental pressures from an increase in seawater alkalinity set the stage for an unprecedented geobiological response: the evolutionary novelty of animal biomineralization.

Production of a gadolinium-loaded liquid scintillator for the Daya Bay reactor neutrino experiment

We report on the production and characterization of liquid scintillators for the detection of electron antineutrinos by the Daya Bay reactor neutrino experiment. A 185 tons of gadolinium-loaded (0.1% by mass) liquid scintillator (Gd-LS) and a 200 tons of unloaded liquid scintillator (LS) were successfully produced from a linear-alkylbenzene (LAB) solvent in 6 months. The scintillator properties, the production and purification systems, and the quality assurance and control (QA/QC) procedures are described. © 2014 Elsevier B.V