Distribution and dynamics of niche and interspecific association of dominant phytoplankton species in the Feiyun River basin,Zhejiang,China

To investigate the dominant species and interspecific association in the phytoplankton community of the Feiyun River basin in Zhejiang Province,East China,the main stream and the Shanxi Zhaoshandu Reservoir in the downstream were chosen as the study area,for which 22 sampling sites were designated.Sampling was conducted in September 2021,January,May,and July 2022.Phytoplankton species were identified from both quantitative samples and in-vivo observations.Phytoplankton was quantified by direct counting.Results show that there were 98 species belonging to 6 phyla and 78 genera.In addition,to clarify the niches of the dominant phytoplankton species and their interspecific association,the dominance index was calculated,and a comprehensive analysis was conducted including niche width,niche overlap value,ecological response rate,overall association,chi-square test,and the stability.The phytoplankton community exhibited characteristics of a Cyanobacteria-Chlorophyta-Diatom type community,showing higher diversity in spring and lower diversity in summer.Among 11 dominants phytoplankton species from 3 phyla,both frequency and dominance degree varied seasonally,of which Microcystis sp.was the dominant species in Spring,Autumn,and Winter.The niche widths of the dominant species ranged from 0.234 to 0.933,and were categorized into three groups.The niche overlap values of the 11 dominant species ranged from 0.359 to 0.959,exhibiting significant seasonal differences-highest in winter followed by autumn,spring,and summer in turn.The overall correlation among dominant species in all four seasons revealed a non-significant negative association,resulting in an unstable community structure.A significant portion(84.2%)of species pairs displayed positive associations,suggesting a successional pattern where Diatoms dominated while other dominant species shared resources and space.Despite this pattern,stability measurements indicated that the dominant species community remained unstable.Therefore,careful monitoring is recommended for potential water environment issues arising from abnormal proliferation of dominant species in the watershed during winter.This research built a theoretical foundation with a data support to the early warning of eutrophication and provided a reference for water resources management in similar watersheds along the eastern coast of China.

A new perspective on changes in vascular function due to hypoxia

This review discusses the functions of blood vessels such as coagulation,regulation,immunity,endocrinology,and nerve conduction from a new perspective and suggests that hypoxia plays a common role in the changes in vascular function in various cardiovascular and cerebrovascular diseases.Therefore,it is oxygen therapy regulation may be a particularly beneficial means by which to regulate vascular function due to its low risk of harm and ease of implementation.Further,the authors have identified a link between vascular function and diseases caused by endogenous hypoxia and analyzed it in depth.The potential effects of hypoxia regulation schemes such as hyperxia,hyperoxic-hypoxia alternations,hypoxia preconditioning,and intermittent hypoxia on vascular function are also discussed,and we present theoretical support for targeted vascular therapy.

Neurogranin as an important regulator in swimming training to improve the spatial memory dysfunction of mice with chronic cerebral hypoperfusion

Background:Vascular cognitive impairment caused by chronic cerebral hypoperfusion(CCH)has become a hot issue worldwide.Aerobic exercise positively contributes to the preservation or restoration of cognitive abilities;however,the specific mechanism has remained inconclusive.And recent studies found that neurogranin(Ng)is a potential biomarker for cognitive impairment.This study aims to investigate the underlying role of Ng in swimming training to improve cognitive impairment.Methods:To test this hypothesis,the clustered regularly interspaced short palindromic repeats(CRISPR)-associated protein 9(Cas9)system was utilized to construct a strain of Ng conditional knockout(Ng cKO)mice,and bilateral common carotid artery stenosis(BCAS)surgery was performed to prepare the model.In Experiment 1,2-month-old male and female transgenic mice were divided into a control group(wild-type littermate,n=9)and a Ng cKO group(n=9).Then,2-month-old male and female C57BL/6 mice were divided into a sham group(C57BL/6,n=12)and a BCAS group(n=12).In Experiment 2,2-month-old male and female mice were divided into a sham group(wild-type littermate,n=12),BCAS group(n=12),swim group(n=12),BCAS+Ng cKO group(n=12),and swim+Ng cKO group(n=12).Then,7 days after BCAS,mice were given swimming training for 5 weeks(1 week for adaptation and 4 weeks for training,5 days a week,60 min a day).After intervention,laser speckle was used to detect cerebral blood perfusion in the mice,and the T maze and Morris water maze were adopted to test their spatial memory.Furthermore,electrophysiology and Western blotting were conducted to record long-term potential and observe the expressions of Ca^(2+)pathway-related proteins,respectively.Immunohistochemistry was applied to analyze the expression of relevant markers in neuronal damage,inflammation,and white matter injury.Results:The figures showed that spatial memory impairment was detected in Ng cKO mice,and a sharp decline of cerebral blood flow and an impairment of progressive spatial memory were observed in BCAS mice.Regular swimming training improved the spatial memory impairment of BCAS mice.This was achieved by preventing long-term potential damage and reversing the decline of Ca^(2+)signal transduction pathway-related proteins.At the same time,the results suggested that swimming also led to improvements in neuronal death,inflammation,and white matter injury induced by CCH.Further study adopted the use of Ng cKO transgenic mice,and the results indicated that the positive effects of swimming training on cognitive impairments,synaptic plasticity,and related pathological changes caused by CCH could be abolished by the knockout of Ng.Conclusion:Swimming training can mediate the expression of Ng to enhance hippocampal synaptic plasticity and improve related pathological changes induced by CCH,thereby ameliorating the spatial memory impairment of vascular cognitive impairment.

Recent progress in flame retardant technology of battery: A review

As one of the most popular research directions,the application safety of battery technology has attracted more and more attention,researchers in academia and industry are making efforts to develop safer flame retardant battery.The battery consists of electrolyte,separator,electrode and shell,the traditional flame retardant method of battery is to modify the components to improve its flame safety.In this review,varied types of battery flame retardant technology are initially described,including the type of flame-retardants,flame retardant behaviors and flame retardant mechanisms.Latest research progress of various battery flame retardant technologies is summarized.Typical flame retardant approaches and important properties of flame retardant battery are reviewed as well.In addition,the current main challenges of the battery flame retardant technology in both academics and the industrial are analyzed carefully.In the end,the perspectives for future development of battery flame retardant technology are briefly discussed.

MXene-based all-solid flexible electrochromic microsupercapacitor

With the increasing demand for multifunctional optoelectronic devices,flexible electrochromic energy storage devices are being widely recognized as promising platforms for diverse applications.However,simultaneously achieving high capacitance,fast color switching and large optical modulation range is very challenging.In this study,the MXenebased flexible in-plane microsupercapacitor was fabricated via a mask-assisted spray coating approach.By adding electrochromic ethyl viologen dibromide(EVB)into the electrolyte,the device showed a reversible color change during the charge/discharge process.Due to the high electronic conductivity of the MXene flakes and the fast response kinetics of EVB,the device exhibited a fast coloration/bleaching time of 2.6 s/2.5 s,a large optical contrast of 60%,and exceptional coloration efficiency.In addition,EVB acted as a redox additive to reinforce the energy storage performance;as a result,the working voltage window of the Ti_(3)C_(2)-based symmetric aqueous microsupercapacitor was extended to 1 V.Moreover,the device had a high areal capacitance of 12.5 mF cm^(−2)with superior flexibility and mechanical stability and showed almost 100%capacitance retention after 100 bending cycles.The as-prepared device has significant potential for a wide range of applications in flexible and wearable electronics,particularly in the fields of camouflage,anticounterfeiting,and displays.

Enhanced therapeutic effects of apoptotic cell-conditioned mesenchymal stem cells in lupus-prone MRL/lpr mice

Background::Apoptotic cell-conditioned mesenchymal stem cells (AC-MSCs) exhibit stronger T cell suppressive ability via cyclooxygenase 2 (COX2)/prostaglandin E2 (PGE2);however, whether AC-MSCs exhibit enhanced therapeutic effects on systemic lupus erythematosus (SLE) remains unknown. Methods: Splenocytes from MRL/MPJ-Fas lpr (MRL /lpr) mice were cocultured with AC-MSCs, and the proportion of plasma cells was determined by flow cytometry. MSCs, AC-MSCs, COX2 knockdown MSCs, and COX2 knockdown AC-MSCs were infused into MRL/ lpr mice ( n = 10/group). Survival rates and lupus symptoms, including proteinuria, kidney injury, renal immune complex deposition, and autoantibody production, were assessed. Additionally, the number of plasma cells and serum levels of inflammatory cytokines were measured. Results::The AC-MSCs significantly inhibited plasma cells via PGE2 after 24 h coculture in vitro, whereas MSCs did not. In the MRL /lpr mice, AC-MSC treatment led to a significantly higher survival rate than phosphate-buffered saline (PBS) treatment (90% vs. 50%, p < 0.05). Moreover, AC-MSC infusion decreased urine protein levels as early as 1 week after administration (0.89 ± 0.55 mg/mL vs. 1.59 ± 0.60 mg/mL, p < 0.05, compared with PBS treatment). Administration of both MSCs and AC-MSCs reduced renal immunoglobulin G and complement C3 deposition, whereas COX2 knockdown MSCs and COX2 knockdown AC-MSCs did not. Serum anti-dsDNA antibody levels in AC-MSC-treated mice significantly decreased (0.40 ± 0.25 vs. 0.99 ± 0.58, p < 0.05), compared with PBS treatment, as well as the number of plasma cells in both the spleen ([2.14 ± 1.05] × 10^(6) vs. [8.02 ± 4.01] × 10^(6), p < 0.01) and renal-draining lymph nodes ([0.78 ± 0.68] × 10^(6) vs. [2.49 ± 1.45] × 10^(6), p < 0.05). Additionally, AC-MSCs inhibited the production of inflammatory cytokines, including interleukin-21, tumor necrosis factor-alpha, and monocyte chemoattractant protein-1. Conclusions::AC-MSCs enhanced the therapeutic effects in mice with lupus, which were partially mediated by COX2/PGE2. Therefore, AC preconditioning may be a new strategy for MSC transplantation in the treatment of SLE.

Abnormal Metabolic Connectivity in Rats at the Acute Stage of Ischemic Stroke

Stroke at the acute stage is a major cause of disability in adults, and is associated with dysfunction of brain networks. However, the mechanisms underlying changes in brain connectivity in stroke are far from fully elucidated. In the present study, we investigated brain metabolism and metabolic connectivity in a rat ischemic stroke model of middle cerebral artery occlusion （MCAO） at the acute stage using 18F-fluorodeoxyglucose positron emission tomography. Voxel-wise analysis showed decreased metabolism mainly in the ipsilesional hemi- sphere, and increased metabolism mainly in the contrale- sional cerebellum. We used further metabolic connectivity analysis to explore the brain metabolic network in MCAO. Compared to sham controls, rats with MCAO showed most significantly reduced nodal and local efficiency in the ipsilesional striatum. In addition, the MCAO group showed decreased metabolic central connection of the ipsilesional striatum with the ipsilesional cerebellum, ipsilesional hippocampus, and bilateral hypothalamus. Taken together, the present study demonstrated abnormal metabolic con- nectivity in rats at the acute stage of ischemic stroke, which might provide insight into clinical research.

Wave‑Shaped Piezoelectric Nanofber Membrane Nanogenerator for Acoustic Detection and Recognition

With the rapid development of internet of things and wearable electronics,how to conveniently power uncountable sensors remains a huge challenge.Energy harvesting strategy is suggested to collect and convert environmental energies into electrical energy.Thereinto,piezoelectric polymers are utilized as fexible harvesters to convert mechanical energy.The latter widely distributes in both our daily life and industrial environment.Intrinsic piezoelectric property further drives piezoelectric polymers to construct fexible self-powered strain sensors.However,relatively low piezoelectric performance restricts their application in detection and conversion of weak mechanical excitations.Herein,wave-shaped 3D piezoelectric device was fabricated by embossing electrospun polyvinylidene fuoride nanofbers.This 3D structured device presents better longitudinal and transverse piezoelectric performance than usual fat-type one.This wave-shaped piezoelectric device was developed for acoustic detection and recognition with a frequency resolution better than 0.1 Hz.This wave-shaped device was capable of frequency spectrum analyses of various sound sources from human and animals and well presents its potential for future wearable acoustic sensors and transducers.

Superconductivity in two-dimensionalη-Mo3C2 films

Two-dimensional(2D)superconductors have intriguing physical properties and abundant potential applications.Recently,2D superconductingα-Mo2C and facecentered cubic Mo2C have been controllably prepared and they bring new viewpoints to carbon-based superconductivity.Although molybdenum carbides(Mo-Cs)have multiple crystalline stacking orders,there are still few structures reported for the lack of higher energy supply during growth.In this study,we report a two-step vapor deposition method to grow superconducting η-Mo3C2 films with different thicknesses,with the assistance of controllable plasma power.The grownη-Mo3C2 films show polycrystalline characteristics,but they still present superior superconductivity.The 3.0-nm-thick film has the superconducting transition temperature of 5.38 K,and its electrical performances follow truly 2D superconducting transitions.This study will not only exhibit a robust superconductingη-Mo3C2 ultrathin film,but also provides a convenient growth way to realize more carbide-based heterostructures for future device applications.