Anomalous electrical transport and magnetic skyrmions in Mn-tuned Co9Zn9Mn2 single crystals

\b{eta}-Mn-type CoxZnyMnz (x + y + z = 20) alloys have recently attracted increasing attention as a new class of chiral magnets with skyrmions at and above room temperature. However, experimental studies on the transport properties of this material are scarce. In this work, we report the successful growth of the \b{eta}-Mn-type Co9.24Zn9.25Mn1.51 and Co9.02Zn9.18Mn1.80 single crystals and a systematic study on their magnetic and transport properties. The skyrmion phase was found in a small temperature range just below the Curie temperature. The isothermal ac susceptibility and dc magnetization as a function of magnetic field confirm the existence of the skyrmion phase. A negative linear magnetoresistance over a wide temperature range from 2 K to 380 K is observed and attributed to the suppression of the magnetic ordering fluctuation under high fields. Both the magnetization and electrical resistivity are almost isotropic. The quantitative analysis of the Hall resistance suggests that the anomalous Hall effect of Co9.24Zn9.25Mn1.51 and Co9.02Zn9.18Mn1.80 single crystals is dominated by the intrinsic mechanism. Our findings contribute to a deeper understanding of the properties of CoxZnyMnz (x + y + z = 20) alloys material and advance their application in spintronic devices.Comment: 7 figure

An Instrument for In Situ Measuring the Volume Scattering Function of Water: Design, Calibration and Primary Experiments

The optical volume scattering function (VSF) of seawater is a fundamental property used in the calculation of radiative transfer for applications in the study of the upper-ocean heat balance, the photosynthetic productivity of the ocean, and the chemical transformation of photoreactive compounds. A new instrument to simultaneously measure the VSF in seven directions between 20° to 160°, the attenuation coefficient, and the depth of water is presented. The instrument is self-contained and can be automatically controlled by the depth under water. The self-contained data can be easily downloaded by an ultra-short-wave communication system. A calibration test was performed in the laboratory based on precise estimation of the scattering volume and optical radiometric calibration of the detectors. The measurement error of the VSF measurement instrument has been estimated in the laboratory based on the Mie theory, and the average error is less than 12%. The instrument was used to measure and analyze the variation characteristics of the VSF with angle, depth and water quality in Daya Bay for the first time. From these in situ data, we have found that the phase functions proposed by Fournier-Forand, measured by Petzold in San Diego Harbor and Sokolov in Black Sea do not fit with our measurements in Daya. These discrepancies could manly due to high proportion of suspended calcium carbonate mineral-like particles with high refractive index in Daya Bay

The peptidoglycan-associated lipoprotein gene mutant elicits robust immunological defense in mice against Salmonella enteritidis

BackgroundSalmonella enteritidis (S. enteritidis), a zoonotic pathogen with a broad host range, presents a substantial threat to global public health safety. Vaccination stands as an effective strategy for the prevention and control of S. enteritidis infection, highlighting an immediate clinical need for the creation of safe and efficient attenuated live vaccines.MethodsIn this study, a S. enteritidis peptidoglycan-associated lipoprotein (pal) gene deletion strain (Δpal), was constructed. To assess its virulence, we conducted experiments on biofilm formation capability, motility, as well as cell and mouse infection. Subsequently, we evaluated the immune-protective effect of Δpal.ResultsIt was discovered that deletion of the pal gene reduced the biofilm formation capability and motility of S. enteritidis. Cell infection experiments revealed that the Δpal strain exhibited significantly decreased abilities in invasion, adhesion, and intracellular survival, with downregulation of virulence gene expression, including mgtC, invH, spvB, sipA, sipB, ssaV, csgA, and pipB. Mouse infection experiments showed that the LD50 of Δpal increased by 104 times, and its colonization ability in mouse tissue organs was significantly reduced. The results indicated that the pal gene severely affected the virulence of S. enteritidis. Further, immunogenicity evaluation of Δpal showed a significant enhancement in the lymphocyte transformation proliferation capability of immunized mice, producing high titers of specific IgG and IgA, suggesting that Δpal possesses good immunogenicity. Challenge protection tests demonstrated that the strain could provide 100% immune protection against wild-type strains in mice.DiscussionThis study proves that the pal gene influences the virulence of S. enteritidis, and Δpal could serve as a candidate strain for attenuated live vaccines, laying the foundation for the development of attenuated live vaccines against Salmonella

Plant immunity suppression by an exo-β-1,3-glucanase and an elongation factor 1α of the rice blast fungus

Fungal cell walls undergo continual remodeling that generates β-1,3-glucan fragments as products of endo-glycosyl hydrolases (GHs), which can be recognized as pathogen-associated molecular patterns (PAMPs) and trigger plant immune responses. How fungal pathogens suppress those responses is often poorly understood. Here, we study mechanisms underlying the suppression of β-1,3-glucan-triggered plant immunity by the blast fungus Magnaporthe oryzae. We show that an exo-β-1,3-glucanase of the GH17 family, named Ebg1, is important for fungal cell wall integrity and virulence of M. oryzae. Ebg1 can hydrolyze β-1,3-glucan and laminarin into glucose, thus suppressing β-1,3-glucan-triggered plant immunity. However, in addition, Ebg1 seems to act as a PAMP, independent of its hydrolase activity. This Ebg1-induced immunity appears to be dampened by the secretion of an elongation factor 1 alpha protein (EF1α), which interacts and co-localizes with Ebg1 in the apoplast. Future work is needed to understand the mechanisms behind Ebg1-induced immunity and its suppression by EF1α

Comparisons of heat treatment on the electrochemical performance of different carbons for lithium-oxygen cells

Lithium-oxygen (Li-O2) cells are a promising power source, and carbons are an attractive non-metal catalyst for air electrodes. To improve the electrochemical performance, various carbons are heated in an inert atmosphere. It is found that heat treatment at 900 C can differently improve the electrochemical performance of multiwalled carbon nanotubes (CNTs), acetylene carbon black (AB) and activated carbon (AC), but the improvement of CNTs is the most obvious. After heat treatment, the peak current density of the oxygen reduction reaction (ORR) and the 1st discharge capacity of CNTs increase ∼30% and ∼125%, respectively, while the charge transfer reaction resistance and the Warburg diffusion resistance decrease ∼7.0% and ∼11.1%, respectively. AC has the highest charge capacities and capacity retention ratio in spite of little influence by heat treatment. The possible mechanism and reasons are analyzed using different techniques. Microstructure is superior to conductivity for enhancing the rechargeability and the cyclability, and heat treatment is effective for some carbon materials in improving the electrochemical performance of Li-O2 cells. © 2014 Elsevier Ltd

Effects of Biodegradable Film and Polyethylene Film Residues on Soil Moisture and Maize Productivity in Dryland

With the dramatic increased use of agricultural film, the potential environmental risks associated with it have been receiving widespread attention. Biodegradable film (BF) is considered an alternative to conventional polyethylene film (PF), but its feasibility to replace PF needs to be verified. Thus, we conducted a two-year field experiment in the Loess Plateau region of China, exploring the effects of residual biodegradable film and polyethylene film (RBF and RPF) on soil moisture, maize root, and productivity at different residual levels (75 kg ha−1, 150 kg ha−1 and 300 kg ha−1). Regardless of the residual film type, soil water content (SWC), root length density (RLD), and root surface area density (RSD) all decreased with increasing residual level; this phenomenon observed significant differences when the residual level exceeded 150 kg ha−1. Different organs (root and shoot) of maize differed in their sensitivity and sensitivity period to residual film. The two-year degradation rate of RBF was 59.24%, which was higher than that of RPF. Compared to the RPF treatments, the SWC, RLD, RSD, biomass, and root–shoot ratio of the RBF treatments were closer to the no residual film treatment in the second maize growing season. After the two-year experiment, compared to the grain yield, water use efficiency, and precipitation use efficiency of the RPF treatments, that of the RBF treatments increased 0.41–6.24%, 0.12–4.44%, and 0.41–06.24%. The application of BF to replace PF is beneficial to sustainable maize production in dryland, but finding efficient methods to recycle the residual film remains a priority

Development of an In Situ Analyzer Based on Sequential Injection Analysis and Liquid Waveguide Capillary Flow Cell for the Determination of Dissolved Reactive Phosphorus in Natural Waters

This study presents an innovative technique for the in situ analysis of aquatic biochemical elements detected through wet chemical processes. A new compact in situ phosphate analyzer based on sequential injection analysis, liquid waveguide capillary flow cell and spectrophotometry was developed, and a safe and modular electronics-chemical separation mechanical structure was designed. The sequential injection system of this analyzer was optimized, and the major functions of this analyzer were studied and estimated. With a 10 cm liquid waveguide capillary flow cell and a 6.3 min time cost of detection, the analyzer reaches a detection limit of 1.4 μg·L−1 (≈14.7 nM, [PO43−]) and a consumption of 23 μL at most for each reagent. This analyzer was operated in situ and online during two scientific research cruises in the Pearl River Estuary and northern South China Sea. The advantages of this analyzer include its simple versatile manifold, full automation, low chemical consumption and electronics-chemical separate safe structure. Long-term in situ performance of this analyzer will be validated in the future

Efficacy of Root Zone Temperature Increase in Root and Shoot Development and Hormone Changes in Different Maize Genotypes

In the context of global warming, the effects of warming in the root zone of crops on maize seedling characteristics deserve research attention. Previous studies on the adaptive traits of dryland maize have mainly focused on soil moisture and nutrients, rather than analyzing potential factors for the adaptive traits of root zone warming. This study was conducted to investigate the effects of different root zone warming ranges on the agronomic traits, hormones, and microstructures of maize seedling roots and leaves. The results showed that minor increases in the root zone temperature significantly enhanced maize seedling growth. However, when the temperature in the root zone was excessive, the stem diameter, root surface area, root volume, total root length, dry matter accumulation, and root/shoot biomass of maize seedlings sharply decreased. Under high temperature stress in the root zone, the root conduit area; root stele diameter; root content of trans-zeatin (ZT), gibberellin A3 (GA3), and indoleacetic acid (IAA); leaf thickness; upper and lower epidermis thickness; and leaf content of ZT and GA3 were significantly decreased. The hormone content and microstructure changes might be an important reason for root growth maldevelopment and nutrient absorption blockage, and they also affected the leaf growth of maize seedlings. Compared with the ‘senescent’ maize type Shaandan 902 (SD902), the plant microstructure of the ‘stay-green’ maize type Shaandan 609 (SD609) was less affected by increased temperatures, and the ability of the root system to absorb and transport water was stronger, which might explain its tolerance of high temperature stress in the root zone

Highly hydrophilic and dispersed TiO2 nano-system with enhanced photocatalytic antibacterial activities and accelerated tissue regeneration under visible light

Abstract Titanium dioxide (TiO2)-based photodynamic antibacterial (PDA) agents present a novel approach for addressing drug-resistant bacterial infections and the associated tissue damage. However, the suboptimal dispersibility, negative charge, and weak photocatalytic activity under visible light of TiO2 hinder its practical applications. This study aimed to address these limitations by developing a highly hydrophilic and dispersed Zn-TiO2/reduced graphene oxide (rGO) (HTGZ) nano-system with exceptional visible light catalytic activity and tissue repair ability. HTGZ produced an antibacterial ratio over 98% within a short time, likely due to the enhanced production of reactive oxygen species under visible light. After being co-cultured for 4 days, L929 cells and BMSCs maintained over 90% activity, indicating that HTGZ had no significant cytotoxicity. Furthermore, the transcriptomic and metabolic analyses revealed that the antibacterial mechanism mainly came from the destruction of cell membranes and the disruption of various metabolic processes, such as purine metabolism and fatty acid biosynthesis. Critically, results of in vivo experiments had authenticated that HTGZ significantly promoted infected tissue regeneration by slaughtering bacteria and release Zn2+. After 14 days, the wound area was only one-third that of the control group. Overall, the enhanced antibacterial efficacy and wound-healing potential position HTGZ as a promising nano-antibacterial medication for the clinical treatment of infectious bacterial diseases