Effect of nonlinear and noncollinear transformation strain pathways in phase-field modeling of nucleation and growth during martensite transformation

The phase-field microelasticity theory has exhibited great capacities in studying elasticity and its effects on microstructure evolution due to various structural and chemical non-uniformities (impurities and defects) in solids. However, the usually adopted linear and/or collinear coupling between eigen transformation strain tensors and order parameters in phase-field microelasticity have excluded many nonlinear transformation pathways that have been revealed in many atomistic calculations. Here we extend phase-field microelasticity by adopting general nonlinear and noncollinear eigen transformation strain paths, which allows for the incorporation of complex transformation pathways and provides a multiscale modeling scheme linking atomistic mechanisms with overall kinetics to better describe solid-state phase transformations. Our case study on a generic cubic to tetragonal martensitic transformation shows that nonlinear transformation pathways can significantly alter the nucleation and growth rates, as well as the configuration and activation energy of the critical nuclei. It is also found that for a pure-shear martensitic transformation, depending on the actual transformation pathway, the nuclei and austenite/martensite interfaces can have nonzero far-field hydrostatic stress and may thus interact with other crystalline defects such as point defects and/or background tension/compression field in a more profound way than what is expected from a linear transformation pathway. Further significance is discussed on the implication of vacancy clustering at austenite/martensite interfaces and segregation at coherent precipitate/matrix interfaces.National Science Foundation (U.S.). Division of Materials Research (DMR-1410322)National Science Foundation (U.S.). Division of Materials Research (DMR-1410636

Single-Sample Finger Vein Recognition via Competitive and Progressive Sparse Representation

As an emerging biometric technology, finger vein recognition has attracted much attention in recent years. However, single-sample recognition is a practical and longstanding challenge in this field, referring to only one finger vein image per class in the training set. In single-sample finger vein recognition, the illumination variations under low contrast and the lack of information of intra-class variations severely affect the recognition performance. Despite of its high robustness against noise and illumination variations, sparse representation has rarely been explored for single-sample finger vein recognition. Therefore, in this paper, we focus on developing a new approach called Progressive Sparse Representation Classification (PSRC) to address the challenging issue of single-sample finger vein recognition. Firstly, as residual may become too large under the scenario of single-sample finger vein recognition, we propose a progressive strategy for representation refinement of SRC. Secondly, to adaptively optimize progressions, a progressive index called Max Energy Residual Index (MERI) is defined as the guidance. Furthermore, we extend PSRC to bimodal biometrics and propose a Competitive PSRC (C-PSRC) fusion approach. The C-PSRC creates more discriminative fused sample and fusion dictionary by comparing residual errors of different modalities. By comparing with several state-of-the-art methods on three finger vein benchmarks, the superiority of the proposed PSRC and C-PSRC is clearly demonstrated

Eupatilin Attenuates Ethanol Withdrawal-Induced Anxiety-like Behavior in Rats by Improving Ventral Hippocampus GABAa Transmission

Objective: To study the improving effect of Eupatilin (Eptl) on ethanol withdrawal (EtOHWI)-induced anxiety-like behavior in rats and probe the mechanisms related to ventral hippocampus (vHippo). Methods: Thirty-two adult male Sprague-Dawley rats were randomly divided into four groups, 8 rats per group: Saline-treated control group, EtOHWI model group, low-dose Eptl treatment group and high-dose Eptl treatment group. The EtOHWI was established by intraperitoneal injection of 3 g/kg of ethanol (20% volume/volume, dissolved in saline) once a day for 28 days followed by 3 days of withdrawal, during the withdrawal period, the low-and the high-dose Eptl treatment groups were respectively given 10 and 30 mg/kg Eptl through oral route once a day, while the saline control group was administered with an equal volume of saline. Thirty minutes after the third Eptl, all the rats were subjected to open filed (OF) and elevated plus maze (EPM) tests to detect anxiety-like behaviors. The serum coritosterone (CORT) concentration and vHippo γ-aminobutyric acid (GABA) secretion were measured by enzyme linked immunosorbent assay (ELISA), and vHippo glutamic acid decarboxylase 67 (GAD 67) mRNA relative expression was assayed by real-time quantitative polymerase chain reaction. The protein expression of GABAa receptor α1 (GABAaRα1), GABAaRα2, nuclear factor E2-related factor 2 (Nrf2), heme oxygense-1 (HO-1) in the vHippo were analyzed by Western blot. The levels of MDA, T-SOD, CAT and GSH, IL-6 and TNF-α were measured by commercial kits. Meanwhile, in the in vitro experiment, the nuclear levels of Nrf2 in HT22 cells were detected via immunofluorescent technique. Results: Compared with the rats in the EtOHWI group, the rats in low and high-dose Eptl treatment groups moving distance increased significantly (P<0.01) in the central region of OF which was 70.62% and 124.21% respectively, and moving time increased significantly (P<0.05 or P<0.01) which was 251.75% and 371.62% respectively in the central zone of the OF. Visited more frequently (P<0.05 or P<0.01) which was 110.33% and 207.32% respectively, and stayed time increased significantly (P<0.05 or P<0.01) which was 99.56% and 184.18% respectively in the open arms of the EPM1. In biochemical assays, compared with those in EtOHWI rats, in the rats of low-dose and high-dose Eptl treatment groups, the serum CORT concentrations decreased significantly (P<0.01). The vHippo GABA and GAD67 mRNA levels increased significantly (P<0.05 or P<0.01). The protein expression of GABAaRα1, GABAaRα2, Nrf2, HO-1 in the vHippo increased significantly (P<0.05 or P<0.01). The level of MDA decreased significantly (P<0.01), while the activities of T-SOD and CAT, as well as the level of GSH increased respectively significantly (P<0.05 or P<0.01). The levels of IL-6 and TNF-α decreased significantly (P<0.05 or P<0.01). In the in vitro experiment, the immunofluorescent assay showed that compared with blank control group, Nrf2 level in nucleus of HT22 stimulated by 200 μmol/L H2O2 increased significantly (P<0.01), whereas pretreatment with 30 μmol/L Eptl inhibited the increase of Nrf2 level (P<0.05). Conclusion: Eptl attenuates EtOHWI-induced anxiety-like behavior in rats, which may be mediated by regulating the vHippo GABAaR transmissional disorder of EtOHWI rats via its antioxidant and anti-inflammatory activities

Multi-omics revealed rumen microbiota metabolism and host immune regulation in Tibetan sheep of different ages

The rumen microbiota and metabolites play an important role in energy metabolism and immune regulation of the host. However, the regulatory mechanism of rumen microbiota and metabolite interactions with host on Tibetan sheep’s plateau adaptability is still unclear. We analyzed the ruminal microbiome and metabolome, host transcriptome and serum metabolome characteristics of Tibetan sheep at different ages. Biomarkers Butyrivibrio, Lachnospiraceae_XPB1014_group, Prevotella, and Rikenellaceae_RC9_gut_group were found in 4 months, 1.5 years, 3.5 years, and 6 years Tibetan sheep, respectively. The rumen microbial metabolites were mainly enriched in galactose metabolism, unsaturated fatty acid biosynthesis and fatty acid degradation pathways, and had significant correlation with microbiota. These metabolites further interact with mRNA, and are co-enriched in arginine and proline metabolism, metabolism of xenobiotics by cytochrome P450, propanoate metabolism, starch and sucrose metabolism, gap junction pathway. Meanwhile, serum metabolites also have a similar function, such as chemical carcinogenesis − reactive oxygen species, limonene and pinene degradation, and cutin, suberine and wax biosynthesis, thus participating in the regulation of the body’s immune and energy-related metabolic processes. This study systematically revealed that rumen microbiota, metabolites, mRNA and serum metabolites of Tibetan sheep were involved in the regulation of fermentation metabolic function and immune level of Tibetan sheep at different ages, which provided a new perspective for plateau adaptability research of Tibetan sheep at different ages

A Spaceborne Mounting Method for Fixing a Cubic Fabry&ndash;P&eacute;rot Cavity in Ultra-Stable Lasers

A spaceborne mounting method for fixing a 100 &times; 100 &times; 100 mm cubic Fabry&ndash;P&eacute;rot (FP) cavity is presented. The method constrains the FP cavity in eight directions with a titanium bracket, PEEK gaskets, and vacuum glue. Three criteria were proposed for judging whether the FP cavity is offset or not during aerospace vibration tests. Results indicate that the proposed method is a reliable, robust, and stable way to fix a cubic FP cavity in ultra-stable lasers (USLs). This approach paves the way for the use of USLs in space

Effects of mental rotation on map representation in orienteers—behavioral and fNIRS evidence

Objective Taking orienteering as an example, this study aimed to reveal the effects of mental rotation on orienteers’ map representation and their brain processing characteristics. Methods Functional near-infrared spectroscopic imaging (fNIRS) was used to explore the behavioral performance and cortical oxyhemoglobin concentration changes of map-represented cognitive processing in orienteering athletes under two task conditions: normal and rotational orientation. Results Compared to that in the normal orientation, athletes’ task performance in the rotated orientation condition was significantly decreased, as evidenced by a decrease in correct rate and an increase in reaction time; in the normal orientation condition, blood oxygen activation in the dorsolateral prefrontal lobe was significantly greater than that in the ventral prefrontal lobe, which was significantly correlated with the correct rate. With rotating orientation, the brain oxygen average of each region of interest was enhanced, and the brain region specifically processed was the ventral prefrontal lobe, specifically correlating with the correct rate. Conclusions Mental rotation constrains the map representation ability of athletes, and map representation in rotational orientation requires more functional brain activity for information processing. Ventral lateral prefrontal lobe activation plays an important role in the map representation task in rotational orientation

The neglected background cues can facilitate finger vein recognition

Recently, finger vein based biometric authentication has attracted considerable attention due to its high efficiency and high security. However, most existing finger vein representation methods focus on vein traits while ignoring background cues, although background cues also convey identity information specific to each individual. In this paper, we leverage background intensity variations in finger vein images as new features to enrich discriminative representation, and accordingly propose a new descriptor named Intensity Orientation Vector (IOV). IOV, scaleable to reflect characteristics of finger tissues, offers additional informative cues for finger vein representation. Furthermore, we propose a new learning scheme named Semantic Similarity Preserved Discrete Binary Feature Learning (SSP-DBFL) for finger vein recognition. Unlike the most bimodal binary feature representation methods, SSP-DBFL preserves high-level semantic similarity in a common Hamming space to exploit the consensus between vein traits and background cues. Specifically, given a finger vein image, we first extract the direction difference vectors (DDV) as the main vein traits and the IOV as the auxiliary background cues. Subsequently, we jointly learn projection functions from these two types of features in a supervised manner, converting the two features into discriminative binary codes with their semantic similarity preserved. Finally, the binary codes are pooled into histogram-based vectors for finger vein representation. Extensive experiments are conducted on five widely used finger vein databases and demonstrate the effectiveness of our proposed IOV and SSP-DBFL

Study on Dynamic Characteristics of Pipeline Jet Cleaning Robot

With the passage of time during pipeline operation, a substantial number of impurities accumulate and adhere to the inner wall of the pipeline. This deposition hinders the pipeline’s ability to function correctly, thereby posing significant hidden risks to people’s lives and the safety of their property. This article focuses on employing pipeline robots for internal cleaning. It examines the jet cleaning process of the spiral-driven pipeline inspection and cleaning robot, aiming to determine the optimal motion state and cleaning parameters for the device within the pipeline. The findings are verified and analyzed through experiments. It was observed that the cleaning effect is enhanced, with a target surface distance of approximately 12- to 13-times the diameter of the nozzle outlet (around 25 mm). In addition, an incident angle of 15° yields favorable cleaning results, with a maximum shear force exerted on the target surface of approximately 0.11 MPa. Ensuring that the pipelines operate reasonably and stably, thus guaranteeing their safe functioning and preventing significant economic and environmental damage, holds immense value