Single-nucleotide polymorphisms are associated with cognitive decline at Alzheimer's disease conversion within mild cognitive impairment patients

INTRODUCTION: The growing public threat of Alzheimer's disease (AD) has raised the urgency to quantify the degree of cognitive decline during the conversion process of mild cognitive impairment (MCI) to AD and its underlying genetic pathway. The aim of this article was to test genetic common variants associated with accelerated cognitive decline after the conversion of MCI to AD. METHODS: In 583 subjects with MCI enrolled in the Alzheimer's Disease Neuroimaging Initiative (ADNI; ADNI-1, ADNI-Go, and ADNI-2), 245 MCI participants converted to AD at follow-up. We tested the interaction effects between individual single-nucleotide polymorphisms and AD diagnosis trajectory on the longitudinal Alzheimer's Disease Assessment Scale-Cognition scores. RESULTS: Our findings reveal six genes, including BDH1, ST6GAL1, RAB20, PDS5B, ADARB2, and SPSB1, which are directly or indirectly related to MCI conversion to AD. DISCUSSION: This genome-wide association study sheds light on a genetic mechanism of longitudinal cognitive changes during the transition period from MCI to AD

Predicted no-effect concentration (PNEC) and assessment of risk for the fungicide, triadimefon based on reproductive fitness of aquatic organisms

Triadimefon, a broad-spectrum, systemic fungicide used to protect agricultural crops is popular in China. However, sub-lethal effects of triadimefon on aquatic organisms remained poorly understood, and its risks to aquatic organisms were unclear. In the current study, thresholds for chronic toxicity to five aquatic organisms were determined and a PNEC based on reproductive fitness of nine aquatic organisms was derived through use of a species sensitivity distribution (SSD). NOECs, based on reproduction or inhabitation of growth, for Oryzias latipes, Daphnia magna, Brachionus calyciflorus, Heterocypris incongruens and Soirodela polyrhiza were 5, 25, 80, 320 and 500 μg L−1, respectively, and the final PNEC derived was 3.66 μg L−1. A screening-level hazard assessment of surface water based on both measured environment concentrations (ND∼5.22 μg L−1) in 3 lakes, 2 reservoirs and 1 river and predicted environment concentrations (0.36–65 μg L−1) in a simulated river and pond, identified unacceptable hazard to aquatic organisms posed by triadimefon, with maximum hazard quotients (HQs) of 1.43 and 17.8, respectively. Potential deleterious effects and hazards or risks of exposure of aquatic organisms from current patterns of use of triadimefon in surface water if of concern. Since HQs were relatively small and the benefits large, it is suggested that mitigations be applied to allow use while minimizing potential for adverse effects on aquatic organisms

Iron-modified biochar and water management regime-induced changes in plant growth, enzyme activities, and phytoavailability of arsenic, cadmium and lead in a paddy soil

The aim of this study was to evaluate the effect of raw (RawBC) and iron (Fe)-modified biochar (FeBC) derived from Platanus orientalis Linn branches on the plant growth, enzyme activity, and bioavailability and uptake of As, Cd, and Pb by rice in a paddy soil with continuously flooded (CF) or alternately wet and dry (AWD) irrigation in a pot experiment. Application of RawBC (3%, w/w) significantly increased soil pH, while FeBC decreased it. The FeBC was more effective in reducing As and Pb bioavailability, particularly under the AWD water regime, while RawBC was more conducive in reducing Cd bioavailability under the CF water regime. The FeBC decreased As concentration, but increased concentrations of Cd and Pb in the straw and brown rice, as compared to the untreated soil. Soil catalase and urease activities were enhanced by RawBC, but decreased by FeBC treatment. The FeBC increased the grain yield by 60 and 32% in CF and AWD treatments, respectively. The FeBC can be recommended for immobilization of As in paddy soils, but a potential human health risk from Cd and Pb in FeBC-treated soils should be considered due to increased uptake and translocation of the metals to brown rice

A 4.8-kW high-efficiency 1050-nm monolithic fiber laser amplifier employing a pump-sharing structure

The power scaling of ytterbium-doped fiber (YDF) lasers emitting at the wavelength range of 1030 nm–1060 nm has been limited by amplified spontaneous emission (ASE), stimulated Raman scattering (SRS) effect, and transverse mode instability (TMI). These effects pose challenges in achieving a high-output power laser within the range of 1030 nm–1060 nm while maintaining a high signal-to-noise ratio. Based on a counter-pumped fiber laser amplifier utilizing our self-developed ytterbium-doped fiber, we have successfully showcased a 4.8-kW laser output at 1050 nm, accompanied by an 85.3% slope efficiency and nearly diffraction-limited beam quality. By effectively applying ASE and TMI, and controlling the Raman Stokes at ∼17 dB below the primary signal wavelength, we have achieved optimal performance at the maximum power level. This high efficiency has been attained through a pump-sharing structure combined with cost-effective, non-wavelength-stabilized 976-nm laser diodes

Mechanisms of the imbibition behavior in shales: A critical review

Despite the success of hydraulic fracturing in yielding large production increases from shale gas reservoirs, uncertainties associated with basic transport processes require understanding in order to improve the efficiency and minimize environmental impacts. The hydraulic fracturing process brings in large volumes of water into shale reservoir formations, most of which remains unrecoverable and interferes with shale gas production. The imbibition behavior in shales is commonly observed during the hydraulic fracturing process, and the mechanism greatly influences the hydrocarbon recovery in shale gas reservoirs. In this review, the imbibition models in shales are briefly summarized using the Lucas-Washburn model, piston repulsion model, capillary bundle model, and scalar model. Then the experimental study and numerical simulation of shale imbibition are discussed. Moreover, the influencing factors of the imbibition behavior in shales are analyzed, such as shale and fluid properties. Finally, the main conclusions and the future research direction prospects of the imbibition behavior in shale gas reservoirs are summarized. An accurate description of the imbibition behavior in shale is crucial for optimizing the hydraulic fracturing design and enhancing shale gas production in the development of shale gas reservoirs. It is proposed that the research on the individual influencing factors of shale percolation and the geological mechanism under coupling should be strengthened and that the research on the experimental aspects of shale powder percolation should be emphasized

Thermo-fluidic characteristics and performance in a distribute heating bubble pump generator

In some thermally driven two-phase natural circulation systems, bubble pumps serve as the key driving powers for the cycles. Recently a type of distribute heating bubble pump generator (BPG) is gradually receiving attention due to its compact structure and great potentials to utilize solar energy and low-grade waste heat recovery. The BPG provides a variety of promising features (e.g., passive heat transfer, enhanced reliability), which can benefit the advancing of heat transfer technology. For the primary study, we performed an experiment in a distributed heating BPG. Through utilizing multiple lift tubes and partial visualization configurations, it provides accesses to observe the flow pattern transition and monitor the flow instability, and thus to explore some of the underlying mechanisms affecting BPG performance. Results showed that heat input and immersion height were crucial parameters to enable the operation of distribute heating BPG. With low heat input or high inlet water subcooling level, the flow within the pump was unstable with intermittent flow interruptions. As the heat input increased, the fluid flow became more stable, the vapor generation increased linearly, while the lifted liquid flow rate initially increased then decreased. Correspondingly, the flow pattern at the outlet section of lift tubes gradually changed from slug flow to churn flow, and then to annular flow. The higher of the immersion was, the higher heat input was needed for the flow pattern transition. It was in the churn flow regime at the outlet of lift tubes for the BPG to lift a maximum liquid. At lower immersion level, liquid reflux in the lift tubes was obvious and affected the flow stability as well as the lifting performance. At higher immersion level, the fluid flow was more stable and faster, which lifted more liquid while generated less vapor depending on the inlet subcooling. In general, the BPG showed better performance (both the lifted liquid and vapor generation increased) at smaller inlet subcooling level or lower system pressure. This study highlights the flow pattern evolution and flow stability, which is helpful to the reliable design and effective operation of the distributed heating BPG

A comparison of the distribution and sources of organic matter in surface sediments collected from northwestern and southwestern plateau lakes in China

<p>Surface lacustrine sediments from six plateau lakes in China were analysed for total organic carbon (TOC), total nitrogen, δ¹³C_org, δ¹⁵N_total, aliphatic hydrocarbons, fatty acids (FAs), and alkanols. The FAs and alkanols were fractionated into free and bound subfractions to facilitate investigation of their sources. Higher average TOC levels were observed in sediments from southwestern plateau lakes than in those from northwestern plateau lakes. The sediments from the southwestern plateau lakes may have been contaminated with petroleum hydrocarbons from anthropogenic activities. The molecular compositions of n-alkanes, n-alkanols, and FAs extracted from the lacustrine sediments showed different responses to environmental changes. Most of the n-alkanol and FA distributions were dominated by short-chain components originating from algae and bacteria. However, the presence of long-chain n-alkanes indicate the presence of predominantly terrestrial organic matter (OM) in the sediment samples from the northwestern plateau lakes in China, suggesting that secondary components derived from post-depositional microbial activity were key contributors to the n-alkanols and FAs. Aquatic FAs derived from algae and anaerobic bacteria were a major component of the sedimentary OM and accounted for 65.1-90.2% of the total lipid concentrations.</p