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We attempted to explore the common and distinct long- and short-range functional connectivity (FC) patterns of melancholic and non-melancholic major depressive disorder (MDD) and their associations with clinical characteristics.Fifty-nine patients with first-episode drug-naïve MDD, including 31 patients with melancholic features and 28 patients with non-melancholic features, underwent resting-state functional magnetic resonance imaging (fMRI) scanning to examine long- and short-range FC. Thirty-two healthy volunteers were recruited as controls. The support vector machines (SVM) was applied to distinguish the melancholic patients from the non-melancholic patients by using the FC of abnormal brain regions.Compared to healthy volunteers, patients with MDD showed increased long-range positive FC (lpFC) in the right insula/inferior frontal gyrus and left insula. Relative to non-melancholic patients, melancholic patients displayed decreased lpFC in the right lingual gyrus, decreased short-range positive FC (spFC) in the right middle temporal gyrus and right superior parietal lobule, increased lpFC in the left inferior parietal lobule, and increased spFC in the left middle occipital gyrus/inferior occipital gyrus, left cerebellum VII/IX, and bilateral cerebellum CrusII. Increased lpFC in the left inferior parietal lobule in melancholic patients was correlated with the TEPS abstract anticipatory scores. SVM results showed that FCs of five combinations within different brain regions could distinguish melancholic patients from non-melancholic patients.FC abnormalities in the default mode network and parietal-occipital brain regions may underlie the neurobiology of melancholic MDD. An increased lpFC in the left inferior parietal lobule correlated with anhedonia may be a distinctive neurobiological feature of melancholic MDD.

The relationships between biodiversity-ecosystem functioning (BEF) for microbial communities are poorly understood despite the important roles of microbes acting in natural ecosystems. Dilution-to-extinction (DTE), a method to manipulate microbial diversity, helps to fill the knowledge gap of microbial BEF relationships and has recently become more popular with the development of high-throughput sequencing techniques. However, the pattern of community assembly processes in DTE experiments is less explored and blocks our further understanding of BEF relationships in DTE studies. Here, a microcosm study and a meta-analysis of DTE studies were carried out to explore the dominant community assembly processes and their potential effect on exploring BEF relationships. While stochastic processes were dominant at low dilution levels due to the high number of rare species, the deterministic processes became stronger at a higher dilution level because the microbial copiotrophs were selected during the regrowth phase and rare species were lost. From the view of microbial functional performances, specialized functions, commonly carried by rare species, are more likely to be impaired in DTE experiments while the broad functions seem to be less impacted due to the good performance of copiotrophs. Our study indicated that shifts in the prokaryotic community and its assembly processes induced by dilutions result in more complex BEF relationships in DTE experiments. Specialized microbial functions could be better used for defining BEF. Our findings may be helpful for future studies to design, explore, and interpret microbial BEF relationships using DTE.

The effectiveness of mindfulness-based interventions (MBIs) on the mental health of perinatal women with or without current mental health issues remains unclear.Four electronic databases were searched from inception to October 1, 2021. Data synthesis, sensitivity analysis, subgroup analysis, and quality assessment were performed on the included studies. IA total of 21 RCTs with 1765 perinatal women were enrolled in the meta-analysis. We found MBIs were effective in reducing depression, anxiety, and stress, as well as increasing mindfulness in perinatal women with current mental health issues. However, MBIs were not prior to controls in reducing depression and stress, and increasing mindfulness in perinatal women without current mental health issues. The effectiveness of MBIs on reducing anxiety in perinatal women without current mental health issues was unclear.Considerable heterogeneity was found in the pooled analyses of the RCTs in depression and anxiety in perinatal women with mental health issues and stress in perinatal women without mental health issues.MBIs could serve as a useful addition to existing support for perinatal women with current mental health issues. However, further studies were needed to explore and prove the effectiveness of MBIs on the mental health of perinatal women without current mental health.

We systematically compared the mechanical properties of CrCoNi, a recently emerged prototypical medium-entropy alloy (MEA) with face-centered-cubic (FCC) structure, with hallmark FCC alloys, in particular, the well-known austenitic 316L and 316LN stainless steels, which are also concentrated single-phase FCC solid solutions and arguably next-of-kin to the MEAs. The tensile and impact properties, across the temperatures range from 373 K to 4.2 K, as well as fracture toughness at 298 K and 77 K, were documented. From room temperature to cryogenic temperature, all three alloys exhibited similarly good mechanical properties; CrCoNi increased its tensile uniform elongation and fracture toughness, which was different from the decreasing trend of the 316L and 316LN. On the other hand, the stainless steels showed higher fracture toughness than CrCoNi at all temperatures. To explain the differences in macroscopic mechanical properties of the three alloys, microstructural hardening mechanisms were surveyed. CrCoNi MEA relied on abundant mechanical twinning on the nanoscale, while martensitic transformation was dominant in 316L at low temperatures. The deformation mechanisms in the plastic zone ahead of the propagating crack in impact and fracture toughness tests were also analyzed and compared for the three alloys.

55Cr17Mo1VN high nitrogen martensitic stainless steel is usually applied to the high-quality mold, which is largely produced by the pressurized electro slag remelting process. The microstructure evolution of quenching and tempering heat treatment were investigated and an optimal heat treatment process to achieve excellent mechanical properties was found out. The main precipitates in the steel included carbon-rich type M23C6 and nitrogen-rich type M2N. With increasing austenitizing temperature, the equivalent diameter of the precipitates got fined, and retained austenite content increased significantly when the austenitizing temperature exceeded 1020 °C. The fracture mode gradually changed from brittle fracture to ductile fracture with increasing tempering temperature from 200 to 550 °C. The experimental steel tempered at 350 °C achieved a good combination of hardness (60.6 HRC) and strength (2299.2 MPa) to meet service requirements. Flake M23C6 precipitated along martensite lath boundaries and the secondary hardening phenomenon occurred when the tempering temperature was 450 °C. Due to the high nitrogen content, M2N precipitated from the inside of laths and matrix when tempered at 550 °C.

In this research, the effect of solidification pressure on phase transformation temperature and sequence, amount of proeutectoid ferrite, characteristics of pearlite and carbonitrides have been investigated by microstructure observation, crystal structure and component analysis, and thermodynamic calculation. The microstructure of 30Cr15Mo1N ingot is mainly composed of martensite, austenite, pearlite, ferrite, M23(C,N)6 and M2(C,N). With increasing solidification pressure, M23(C,N)6 precipitation temperature, austenite (γ) and ferrite (δ) formation temperature increase, and M2(C,N) precipitation temperature and ferrite (α) formation temperature decrease. Under 0.5 MPa, the precipitation sequence during solidification process of 30Cr15Mo1N ingot is “L → δ → γ → M2(C,N) → M23(C,N)6 → α + martensite/retained austenite → pearlite”. There is a negligible change in phase transformation sequence with increasing solidification pressure from 0.5 to 2 MPa. In addition, the increment in solidification pressure is beneficial to significantly increase the amount of proeutectoid ferrite and reduce pearlite lamellar spacing by enhancing cooling of 30Cr15Mo1N ingot. Meanwhile, with increasing solidification pressure from 0.5 to 2 MPa, the size of M2(C,N) and the amount of precipitated phases (pearlite and carbonitrides) have a decreasing trend, and the change in the size of M23(C,N)6 can be neglected.

To solve the limitations of clogging and erosion of the submerged entry nozzle (SEN) for the production of high-quality special steel, the chemical reactivity between different alloys and the SEN and the interface reaction between alloys and the SEN controlled by an electric current pulse (ECP) were examined in this study. Results revealed that the chemical reactivity between different alloys and the SEN is different. For example, the reactivity between rare-earth metal and the SEN was strong, while that between Al and the SEN was extremely weak. At the same time, some differences between the clogging and interface reaction by ECP control were observed. Typically, at the positive electrode of the SEN, when a stable and dense clogging layer is formed, the internal SEN was effectively protected. However, at the negative electrode of the SEN, the decarburization rate of the SEN was accelerated by ECP, probably leading to a vicious circle of accelerated clogging and erosion of the SEN. Therefore, in the future, issues of clogging, erosion, infiltration, and decarbonization between active alloys and the SEN in the casting process may be solved and regulated by using the positive electric field of ECP. Meanwhile, the gain effect of ECP also helped to promote the homogenization of molten steel.

Acinetobacter baumannii and methicillin-resistant Staphylococcus aureus (MRSA) are two prevalent pathogens and have developed high resistant to most antibiotics. Therefore, it is a pressing need to develop a new method to inhibit the spread of drug-resistant bacteria. Copper containing high-entropy alloy (HEA, Al0.4CoCrCuFeNi) is a new kind of alloy material, which shows extensive antibacterial activity and mechanical properties in our previous research. This study further develops another HEA (CoCrCuFeNi) and evaluates its resistance against gram-negative A. baumannii and Gram-positive MRSA. The antibacterial tests show that the antibacterial rate of the HEA toward both bacteria reached nearly 99%, far better than the traditional copper-bearing 304 stainless steel (304 Cu-SS). The biofilm observation shows that the HEA could not only kill the planktonic bacteria, but also effectively inhibit the formation of biofilm. These data demonstrate that CoCrCuFeNi HEA possesses effective antibacterial and antibiofilm activities, making it a potential candidate for using in hospital, food industry, and domestic kitchens.

Physical forces, including mechanical stretch, fluid pressure, and shear forces alter lymphatic vessel contractions and lymph flow. Gravitational forces can affect these forces, resulting in altered lymphatic transport, but the mechanisms involved have not been studied in detail. Here, we combine a lattice Boltzmann-based fluid dynamics computational model with known lymphatic mechanobiological mechanisms to investigate the movement of fluid through a lymphatic vessel under the effects of gravity that may either oppose or assist flow. Regularly spaced, mechanical bi-leaflet valves in the vessel enforce net positive flow as the vessel walls contract autonomously in response to calcium and nitric oxide (NO) levels regulated by vessel stretch and shear stress levels. We find that large gravitational forces opposing flow can stall the contractions, leading to no net flow, but transient mechanical perturbations can re-establish pumping. In the case of gravity strongly assisting flow, the contractions also cease due to high shear stress and NO production, which dilates the vessel to allow gravity-driven flow. In the intermediate range of oppositional gravity forces, the vessel actively contracts to offset nominal gravity levels or to modestly assist the favorable hydrostatic pressure gradients.

High cleanliness is a crucial factor determining the service performance of bearing steel. Considering the strong deoxidation ability of carbon under vacuum, vacuum carbon deoxidation was adopted in the cleanliness control of high nitrogen stainless bearing steel. In this paper, a mathematical model for vacuum carbon deoxidation during pressure/vacuum induction melting (PVIM) was proposed considering the occurrence of carbon–oxygen reaction at the free surface of molten pool and at the interface between CO bubbles and molten steel as well as crucible decomposition. The effect of electromagnetic stirring on the mass transfer of oxygen was analyzed using the finite element numerical method and the effect of CO bubbles on the deoxidation process was also considered. The influence of pressure, temperature and initial carbon content on deoxidization was studied and experimentally verified. The results indicated that the predicted variation of oxygen content in molten steel with time agreed well with the experimental results. Electromagnetic stirring effectively promoted the mass transfer of oxygen in molten steel and the carbon–oxygen reaction at free surface of molten pool was the main pathway for deoxidization. The pressure, temperature and initial carbon content influenced the vacuum carbon deoxidation process by affecting the carbon–oxygen reaction rate, crucible decomposition and mass transfer coefficient of oxygen. Finally, optimum melting parameters were recommended.

To reveal the influence mechanism of solidification pressure on the gap width, investigations are performed on the effect of solidification pressure on the interfacial heat transfer mechanism and macroscopically averaged heat transfer coefficient between the H13 ingot and mold. With increasing solidification pressure from 0.1 to 2 MPa, there is an obvious enhancement in the heat transfer from the H13 ingot to the mold. The following quantitative relation between the macroscopically averaged heat transfer coefficient and pressure is proposed: $$ h_{i,P}^{f} = \left( {17.38P^{2} + 155.25P + 1121.7} \right)t^{ - 0.23} . $$ There are three interfacial heat transfer mechanisms, radiation and conduction through the gap between gas pockets and the slightest gap between asperities (or contacting asperities). Increasing pressure can accelerate the formation of the gap between gas pockets, and does not change the maximum value of gap width. In addition, changes in radiation and conduction through the gap between gas pockets are not the main reason for enhancing heat transfer from the ingot to the mold. In the whole process of solidification, increasing pressure is beneficial to retain the intermittent contact at asperities and reduce the macroscopically averaged width of the gap. Consequently, conduction through the slightest gap (or contacting asperities) enhanced by pressure is the major contributor to accelerating heat transfer from the ingot to the mold.

Long range internal stress (LRIS) based mechanism and non-LRIS explanation regarding Bauschinger effect are in debate. LRIS is originated from dislocation pile-up and/or cell generated by the pre-loading, therefore dislocation structure characterization of pre-strained sample is critical to clarify this academic dispute. Dislocation structures in surface and bulk regions of pure Ni deformed to a low strain level are characterized and compared in this work. Discrete dislocations are presented as expected in the bulk region of Ni, however, the main feature in its surface region is dislocation cell with average size of 1.2 μm. The result suggests that the promoted development of dislocation cellular pattern in near-surface region plays a critical role in the Bauschinger effect. It helps to clarify the mechanisms of Bauschinger effect and reconfirm the LRIS based mechanism.

The composition of a slag system has been shown to be particularly important and influential for the new technology of electroslag remelting withdrawal process. The oxidation of the GH984G alloy elements, in contact with different contents of CaF2–CaO–Al2O3–MgO–TiO2–SiO2 in various slag systems, has been investigated in the present study by performing slag–metal equilibrium experiments and ion and molecule coexistence theory analysis. The results show that CaF2 and MgO have only a minor effect on the oxidation rates of Al and Ti in the GH984G superalloys. However, it was found that SiO2 would intensify the oxidation degree of Al and Ti, and Al was found to become easier oxidized than Ti. Moreover, CaO was found to reduce the activity of SiO2 and, thereby, also the oxidation degree of Al and Ti. Also, TiO2 was found to reduce the oxidation rate of Ti and instead increase the oxidation rate of Al. Finally, the effect of Al2O3 on the oxidation of Al and Ti was observed to be opposite to that of TiO2. The calculated results were found to be in good agreement with experimental measurements. Moreover, viscosity experiments showed that CaO would rapidly increase the viscosity of the slag at low temperatures, and that the viscosity of the slag would increase with an increase in SiO2 content.

The trajectory of abnormal cerebellar-cerebral functional connectivity (FC) in patients with obsessive-compulsive disorder (OCD) after pharmacotherapy and the association between alterations in the cerebellar-cerebral FC and changes in the clinical features of patients with OCD, as well as the possibility of building models for diagnosis and prediction of early treatment effects of OCD were unclear. We performed a longitudinal study involving 37 patients with OCD and 37 healthy controls (HCs). Patients with OCD received a 5-week treatment with paroxetine. Resting-state functional magnetic resonance imaging, seed-based FC analyses, support vector machine (SVM), support vector regression (SVR), and correlation analyses were applied to acquire and analyze the imaging and clinical data. Compared with HCs, patients with OCD showed decreased cerebellar-cerebral FC in the executive, affective-limbic, and sensorimotor networks. After treatment, patients showed significant clinical improvement and a part of the decreased cerebellar-cerebral FCs were restored. Negative correlations between abnormal cerebellar-cerebral FC at baseline and severity of compulsions, and impairment of social function were observed. Alterations in the cerebellar-cerebral FC were correlated with changes in cognition. Abnormal cerebellar-cerebral FC at baseline could serve as potential neuroimaging biomarkers for diagnosis of OCD and prediction of early treatment effects. These findings suggested that cerebellar-cerebral FC had an important role in the neuropsychological mechanisms underlying OCD and the pharmacological mechanism underlying the treatment for OCD. It was possible to develop precision medicine to identify individuals with OCD and which patients would maximally benefit from pharmacotherapy through SVM and SVR which were based on cerebellar-cerebral FC.

Early brain functional changes induced by pharmacotherapy in patients with obsessive–compulsive disorder (OCD) in relation to drugs per se or because of the impact of such drugs on the improvement of OCD remain unclear. Moreover, no neuroimaging biomarkers are available for diagnosis of OCD and prediction of early treatment response. We performed a longitudinal study involving 34 patients with OCD and 36 healthy controls (HCs). Patients with OCD received 5-week treatment with paroxetine (40 mg/d). Resting-state functional magnetic resonance imaging (fMRI), regional homogeneity (ReHo), support vector machine (SVM), and support vector regression (SVR) were applied to acquire and analyze the imaging data. Compared with HCs, patients with OCD had higher ReHo values in the right superior temporal gyrus and bilateral hippocampus/parahippocampus/fusiform gyrus/cerebellum at baseline. ReHo values in the left hippocampus and parahippocampus decreased significantly after treatment. The reduction rate (RR) of ReHo values was positively correlated with the RRs of the scores of Yale–Brown Obsessive–Compulsive Scale (Y-BOCS) and obsession. Abnormal ReHo values at baseline could serve as potential neuroimaging biomarkers for OCD diagnosis and prediction of early therapeutic response. This study highlighted the important role of the hippocampal–cortical system in the neuropsychological mechanism underlying OCD, pharmacological mechanism underlying OCD treatment, and the possibility of building models for diagnosis and prediction of early treatment response based on spontaneous activity in the hippocampal–cortical system.

The existence of angular and hard AlN inclusions would seriously deteriorate the service life of high-nitrogen stainless bearing steels (HNSBSs). In this work, the formation mechanism of AlN inclusion in HNSBSs under as-cast, annealing and austenitizing states was systematically investigated by microstructure observation and thermodynamic, kinetic analyses. The results showed that the concentration product of Al and N could exceed the critical solubility of AlN inclusion at liquidus temperature with the Al content higher than 0.050 wt pct, which led to the formation of AlN inclusions about 1 to 5 μm (equivalent diameter) in liquid steel. Based on the ‘Clyne-Kurz’ model, AlN inclusion could form at the solidifying front due to the enrichment of N in the residual liquid steel with the Al content higher than 0.030 wt pct. Besides, the precipitation of Cr2N and the extremely low diffusion coefficient of Al in α phase restrained the precipitation of AlN during annealing at 1023 K. However, AlN and AlN-MnS composite inclusions less than 0.6 μm could precipitate during austenitizing at 1323 K with the Al content higher than 0.006 wt pct, which was the critical Al content to avoid AlN formation in HNSBSs after melting, solidification, and heat treatment processes.

This work investigated the evolution of multiphase microstructure and impact fracture behavior of medium carbon high silicon high strength steel subjected to the austempering treatment at 240, 360, and 400 ℃. The results show that martensite, bainite, and retained austenite (RA) are the main microstructural phases. The austempering treatments at 360 and 400 ℃ caused the formation of carbon-poor ferrite in the matrix, and the transformation of ultrafine bainite into coarse lath bainite and granular bainite, respectively. Thick filmy RA was distributed between bainite laths. The polygonal martensite-austenite islands and blocky RA formed along the grain boundaries. The average carbon concentration in the matrix decreased with the temperature increase, while the impact toughness initially increased and then dropped with temperature. The quasi-cleavage brittle fracture dominated the impact fracture mechanism of the sample austempered at 240 ℃ by forming tearing surfaces and tearing steps. The microcracks disappeared in the RA on the prior austenite grain boundaries. On the other side, the fracture surface of the sample austempered at 360 ℃ exhibited ductile fracture with deep dimples and brittle fracture with cleavage river patterns. The polygonal martensite-austenite islands or blocky RA constrained the microcracks. After austempered at 400 ℃, the brittle fracture was dominant, showing river patterns, and the microcracks propagated through the granular bainite without any resistance.

Objective Previous studies have revealed different neuroimaging features between melancholic and non-melancholic major depressive disorder (MDD). However, homotopic connectivity of melancholic and non-melancholic MDD remains unknown. The present study aimed to explore common and distinct homotopic connectivity patterns of melancholic and non-melancholic MDD and their associations with clinical characteristics. Methods Sixty-four patients with MDD and thirty-two healthy controls were scanned by resting-state functional magnetic resonance imaging (fMRI). Voxel-mirrored homotopic connectivity (VMHC) and pattern classification were applied to analyze the imaging data. Results Relative to healthy controls, melancholic patients displayed decreased VMHC in the fusiform gyrus, posterior cingulate cortex (PCC), superior occipital gyrus (SOG), postcentral gyrus and precentral/postcentral gyrus, and non-melancholic patients displayed decreased VMHC in the PCC. Compared with non-melancholic patients, melancholic patients displayed reduced VMHC in the precentral gyrus and precentral/postcentral gyrus. Support vector machine (SVM) results exhibited VMHC in the precentral gyrus could distinguish melancholic patients from non-melancholic patients with more than 0.6 for specificity, sensitivity and accuracy. Conclusion The study demonstrated common and distinct homotopic connectivity patterns in melancholic and non-melancholic patients. Decreased VMHC in the PCC may be a state-related change for depression, and reduced VMHC in the precentral gyrus and postcentral gyrus may be a distinctive neurobiological feature for melancholic MDD. VMHC in precentral gyrus might be served as potential imaging markers to discriminate melancholic patients from non-melancholic MDD.

Background. Melancholic depression has been assumed as a severe type of major depressive disorder (MDD). We aimed to explore if there were some distinctive alterations in melancholic MDD and whether the alterations could be used to discriminate the melancholic MDD and nonmelancholic MDD. Methods. Thirty-one outpatients with melancholic MDD, thirty-three outpatients with nonmelancholic MDD, and thirty-two age- and gender-matched healthy controls were recruited. All participants were scanned by resting-state functional magnetic resonance imaging (fMRI). Imaging data were analyzed with the network homogeneity (NH) and support vector machine (SVM) methods. Results. Both patient groups exhibited increased NH in the right PCC/precuneus and right angular gyrus and decreased NH in the right middle temporal gyrus compared with healthy controls. Compared with nonmelancholic patients and healthy controls, melancholic patients exhibited significantly increased NH in the bilateral superior medial frontal gyrus and decreased NH in the left inferior temporal gyrus. But merely for melancholic patients, the NH of the right middle temporal gyrus was negatively correlated with TEPS total and contextual anticipatory scores. SVM analysis showed that a combination of NH values in the left superior medial frontal gyrus and left inferior temporal gyrus could distinguish melancholic patients from nonmelancholic patients with accuracy, sensitivity, and specificity of 79.66% (47/59), 70.97% (22/31), and 89.29%(25/28), respectively. Conclusion. Our findings showed distinctive network homogeneity alterations in melancholic MDD which may be potential imaging markers to distinguish melancholic MDD and nonmelancholic MDD.

The effect of La on inclusions and fracture toughness of 40CrNi2Si2MoVA steel was investigated via the optical microscope, scanning electron microscope, image software and electronic universal testing machine. The results reveal that the inclusions in steel without La are mainly MnS and Al2O3–MnS, while the inclusions in steels with La primarily contain La–O–S, La–S and other rare earth complex inclusions contain P and As. La–O–S and La–S are formed under the steelmaking temperature and act as the nucleation core of rare earth complex inclusions containing P and As. According to the segregation model, La–O–S–P–As and La–S–P–As are formed through chemical reactions during the solidification stage. As La content in steels increases from 0 to 0.032 mass%, the average spacing of inclusions is gradually increased from 5.28 to 15.91 μm. The volume fraction of inclusions in steels containing less than 0.018 mass% La approaches 0.006%; however, it is significantly improved to 0.058% when La content is increased to 0.032 mass%. With the increase in La content, the fracture toughness is firstly improved from 63.1 to 80.0 MPa m1/2 due to the increase in average spacing of inclusions and then decreases to 69.6 MPa m1/2 owing to the excessive increase in volume fraction of inclusions. The optimal fracture toughness is found in 40CrNi2Si2MoVA steel with 0.018 mass% La.

Precipitation behavior of P550 steel for non-magnetic drill collars was investigated by microstructure characterization as well as thermodynamic calculation. The results demonstrate that the main precipitate formed at 650–900 °C was cellular Cr2N, and its precipitation depended heavily on the aging temperature. The most sensitive precipitation temperature of cellular Cr2N was 750 °C. At 750 °C, the cellular Cr2N exhibited fast-slow precipitation kinetics with the aging time prolonging. The initial precipitation of cellular Cr2N was governed by the short-range intergranular diffusion of Cr. During long-term aging, its growth was controlled by the long-range bulk diffusion of Cr. In addition, cellular Cr2N induced the precipitation of σ phase ahead of the cell after long period of aging. Increasing the nitrogen content resulted in the increment of both the nucleation site and the driving force for the cellular Cr2N, which jointly promoted its precipitation.

Pressurized electroslag remelting (PESR) has been widely used for preparation of high-quality high nitrogen steels. However, desulfurization might be limited by the pressurized-nitrogen atmosphere in the process. In this paper, the desulfurization behaviors of electroslag remelting in air and nitrogen pressure were investigated and further an appropriate method to improve the sulfur removal in PESR was explored. The results show that the ESR in air maintained relatively high and stable desulfurization ability, but the PESR provided worse sulfur removal owing to the lack of sulfur gasifying oxidation under N2 pressure. With the decline of sulfur distribution coefficient (LS) and the enrichment of sulfur in slag during the remelting, the desulfurization in PESR was gradually weakened. The level of gas pressure had little effect on sulfur removal. The Na2O addition in conventional CaO-Al2O3-CaF2 slags significantly increased the activity of desulfurizers and LS, and slightly improved sulfur mass transfer in slags, then alleviated the negative effect brought by the reduction of desulfurization ability in PESR and achieved higher desulfurization degree. In addition, desulfurization in the remelting was mainly achieved at the liquid metal film of electrode tips, which was benefited from the great reaction specific surface area and high initial sulfur content.

The influence of ultrasonic shot peening (USSP) treatment on the microstructure, corrosion behavior and hydrogen evolution of AZ31 magnesium alloy is investigated. An Fe-rich composite in amorphous state is introduced on the surface layer. Microstructure results indicate that nanoscale grains are formed on the surface layer after USSP treatment. Comparing to the untreated AZ31, the charge transfer resistance of the USSP-treated sample decreases by ~410 times and the hydrogen evolution rate increases by ~64 times. The acceleration of corrosion rate is attributed to the micro-galvanic interaction between the nanocrystalline Mg matrix and amorphous Fe-rich composite.

Intraguild predation (IGP) can have a significant impact on phytoplankton biomass, but its effects on their diversity and assemblage composition are not well understood. In this study, we constructed an IGP model based on the common three-trophic food chain of “fish (or shrimp)–large branchiopods (Daphnia)–phytoplankton”, and investigated the effects of IGP on phytoplankton assemblage composition and diversity in outdoor mesocosms using environmental DNA high-throughput sequencing. Our results indicated that the alpha diversities (number of amplicon sequence variants and Faith’s phylogenetic diversity) of phytoplankton and the relative abundance of Chlorophyceae increased with the addition of Pelteobagrus fulvidraco, while similar trends were found in alpha diversities but with a decrease in the relative abundance of Chlorophyceae in the Exopalaemon modestus treatment. When both predators were added to the community, the strength of collective cascading effects on phytoplankton alpha diversities and assemblage composition were weaker than the sum of the individual predator effects. Network analysis further showed that this IGP effect also decreased the strength of collective cascading effects in reducing the complexity and stability of the phytoplankton assemblages. These findings contribute to a better understanding of the mechanisms underlying the impacts of IGP on lake biodiversity, and provide further knowledge relevant to lake management and conservation.