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As a traditional and popular dietary supplement, lotus rhizome starch (LRS) has health benefits for its many nutritional components and is especially suitable for teenagers and seniors. In this paper, the approximate composition, apparent amylose content (AAC), and structural characteristics of five LRS samples from different regions were investigated, and their correlations with the physicochemical properties of granular and gelatinized LRS were revealed. LRS exhibited rod-shaped and ellipsoidal starch granules, with AAC ranging from 26.6% to 31.7%. LRS-3, from Fuzhou, Jiangxi Province, exhibited a deeper hydrogel color and contained more ash, with 302.6 mg/kg iron, and it could reach the pasting temperature of 62.6 °C. In comparison, LRS-5, from Baoshan, Yunnan Province, exhibited smoother granule surface, less fragmentation, and higher AAC, resulting in better swelling power and freeze-thaw stability. The resistant starch contents of LRS-3 and LRS-5 were the lowest (15.3%) and highest (69.7%), respectively. The enzymatic digestion performance of LRS was positively correlated with ash content and short- and long-term ordered structures but negatively correlated with AAC. Furthermore, the color and network firmness of gelatinized LRS was negatively correlated with its ash content, and the retrograde trend and freeze-thaw stability were more closely correlated with AAC and structural characteristics. These results revealed the physicochemical properties of LRS from different regions and suggested their advantages in appropriate applications as a hydrogel matrix. [ABSTRACT FROM AUTHOR]

One of the most significant transcription factors in plants, WRKYs, are crucial for plant growth and stress response. In this study, we analyzed the physicochemical properties, evolutionary relationships, conservation structure, and expression of the WRKY gene family in S. baicalensis. The WRKY family has highly conserved structural domains, which have been classified into three major categories, I, II, and III, based on the number of WRKY structural domains and zinc finger structural features. SbWRKYs of the same subgroup are functionally similar and essentially contain the same motif. Additionally, different drought stress situations resulted in varying levels of SbWRKYs expression, with the majority of these factors being up-regulated in moderate drought stress settings, and fewer of them were up-regulated under severe drought stress conditions. Under moderate drought stress, the expression of key enzymes increased, while under severe drought stress, the expression of key enzymes decreased. Mild drought stress resulted in a 26.42% increase in baicalin accumulation, while severe drought stress led to a 22.88% decrease. The protein interaction analysis of key enzyme genes and SbWRKYs revealed that the expression of key enzyme genes affected the expression of SbWRKYs. We screened nine SbWRKYs with a significant relationship with baicalin accumulation, and SbWRKY8 and SbWRKY16 showed the highest correlation with the baicalin content. These findings offer a theoretical framework for more research on the roles of SbWRKYs and show that SbWRKYs can respond to drought stress in S. baicalensis. [ABSTRACT FROM AUTHOR]

Wheat (Triticum aestivum L.) is a staple food crop that provides 20% of total human calorie consumption. Gene duplication has been considered to play an important role in evolution by providing new genetic resources. However, the evolutionary fates and biological functions of the duplicated genes in wheat remain to be elucidated. In this study, the resulting data showed that the duplicated genes evolved faster with shorter gene lengths, higher codon usage bias, lower expression levels, and higher tissue specificity when compared to non-duplicated genes. Our analysis further revealed functions of duplicated genes in various biological processes with significant enrichment to environmental stresses. In addition, duplicated genes derived from dispersed, proximal, tandem, transposed, and whole-genome duplication differed in abundance, evolutionary rate, gene compactness, expression pattern, and genetic diversity. Tandem and proximal duplicates experienced stronger selective pressure and showed a more compact gene structure with diverse expression profiles than other duplication modes. Moreover, genes derived from different duplication modes showed an asymmetrical evolutionary pattern for wheat A, B, and D subgenomes. Several candidate duplication hotspots associated with wheat domestication or polyploidization were characterized as potential targets for wheat molecular breeding. Our comprehensive analysis revealed the evolutionary trajectory of duplicated genes and laid the foundation for future functional studies on wheat. [ABSTRACT FROM AUTHOR]

Quantitative measuring of gravity erosion contributes to a better understanding of soil-mass failure occurrence and prediction. However, the measurement of gravity erosion requires the continuous monitoring of the objective terrain, due to its occurrence, usually within seconds, and combination with hydraulic erosion. The photogrammetric technique can quickly obtain terrain data and provide a new method for measuring gravity erosion. Based on a continuous high-overlapping image-acquisition equipment, a Structure-from-Motion-Multi-View-Stereo (SfM-MVS)-integrated workflow, and volume calculation, a new working methodology was established for measuring gravity erosion on steep granitic slopes in the laboratory. The results showed a good match between the digital point clouds derived from SfM-MVS-integrated workflow and terrestrial laser scanning (TLS), achieving millimeter-scale accuracy. The mean distance between the point clouds derived from TLS and SfM-MVS was 1.13 mm, with a standard deviation of 0.93 mm. The relative errors among the volumes calculated by SfM-MVS and TLS or the conventional oven-drying method were all within 10%, with a maximum error of 9.3% and a minimum error of 0.2%. A total of 213 gravitational erosion events were measured in the laboratory by using the SfM-MVS method, further confirming its feasibility. [ABSTRACT FROM AUTHOR]

A miniature Fourier transform spectrometer is proposed using a thin-film lithium niobate electro-optical modulator instead of the conventional modulator made by titanium diffusion in lithium niobate. The modulator was fabricated by a contact lithography process, and its voltage-length and optical waveguide loss were 2.26 V·cm and 1.01 dB/cm, respectively. Based on the wavelength dispersion of the half-wave voltage of the fabricated modulator, the emission spectrum of the input signal was retrieved by Fourier transform processing of the interferogram, and the analysis of the experimental data of monochromatic light shows that the proposed miniaturized FTS can effectively identify the input signal wavelength. [ABSTRACT FROM AUTHOR]

Recent decades have witnessed the rapid progress of nanozymes and their high promising applications in catalysis and bioclinics. However, the comprehensive synthetic procedures and harsh synthetic conditions represent significant challenges for nanozymes. In this study, monodisperse, ultrasmall gold clusters with peroxidase-like activity were prepared via a simple and robust one-pot method. The reaction of clusters with H2O2 and 3,3′,5,5′-tetramethylbenzidine (TMB) followed the Michaelis-Menton kinetics. In addition, in vitro experiments showed that the prepared clusters had good biocompatibility and cell imaging ability, indicating their future potential as multi-functional materials. [ABSTRACT FROM AUTHOR]

Non-alcoholic fatty liver disease (NAFLD) is the most common liver disease and has become a growing public health concern worldwide. Polyphenols may improve high-fat diet (HFD)-related NAFLD. Our previous study found that ferulic acid (FA) and p-coumaric acid (p-CA) were the polyphenols with the highest content in foxtail millet. In this study, we investigated the mechanism underlying the impact of ferulic acid and p-coumaric acid (FA/p-CA) on non-alcoholic fatty liver (NAFLD). The association of FA and p-CA with fatty liver was first analyzed by network pharmacology. Synergistic ameliorating of NAFLD by FA and p-CA was verified in oleic acid (OA) and palmitic acid (PA) (FFA)-treated hepatocytes. Meanwhile, FA/p-CA suppressed final body weight and TG content and improved liver dysfunction in HFD-induced NAFLD mice. Mechanistically, our data indicated that FA and p-CA bind to histone deacetylase 1 (HDAC1) to inhibit its expression. The results showed that peroxisome proliferator activated receptor gamma (PPARG), which is positively related to HDAC1, was inhibited by FA/p-CA, and further suppressed fatty acid binding protein (FABP) and fatty acid translocase (CD36). It suggests that FA/p-CA ameliorate NAFLD by inhibiting free fatty acid uptake via the HDAC1/PPARG axis, which may provide potential dietary supplements and drugs for prevention of NAFLD. [ABSTRACT FROM AUTHOR]

Polyphenol-rich foods are gaining popularity due to their potential beneficial effects in the prevention and treatment of cancer. Foxtail millet is one of the important functional foods, riches in a variety of biologically active substance. Our previous study showed that ferulic acid (FA) and p-coumaric acid (p-CA) are the main anticancer components of foxtail millet bran, and the two have a significant synergistic effect. In the present study, the clinical application potential of FA and p-CA (FA + p-CA) were evaluated in vivo and in vitro. The FA and p-CA target gene enrichment analysis discovered that FA + p-CA were associated with aerobic glycolysis. It was further shown that FA + p-CA remodel aerobic glycolysis by inhibiting the glycolysis-associated lncRNA 495810 and the glycolytic rate-limiting enzyme M2 type pyruvate kinase (PKM2). Moreover, PKM2 expression was positively correlated with lncRNA 495810. More interestingly, the exogenous expression of lncRNA 495810 eliminated the inhibitory effects of FA + p-CA on aerobic glycolysis. Collectively, FA + p-CA obstruct the aerobic glycolysis of colorectal cancer cells via the lncRNA 495810/PKM2 axis, which provides a nutrition intervention and treatment candidate for colorectal cancer. [ABSTRACT FROM AUTHOR]

The hydrological and mechanical properties of granitic residual soils can be significantly altered by periodical wetting and drying (W-D) cycles. The soil structure degradation induced by W-D cycles can lead to soil mass failure and collapsing gully erosion in granitic hilly slopes in south China. However, limited attempts have been made at a comprehensive investigation of the effects of W-D cycles on the structure degradation of granitic residual soils, especially at the pedon scale. The purpose of this paper is to investigate the structural degradation of granite soils induced by W-D cycles and explore its potential influence on the development of collapsing gully erosion. The granitic soil properties, including hydraulic properties, shear strength, and disintegration characteristics, were performed after W-D cycles. The results indicated that the W-D cycles altered the soil pore structure, leading to variations in soil hydraulic properties. Specifically, with increasing alternate W-D cycles, the initial saturated water content and residual water content decreased, while the saturated hydraulic conductivity increased. Meanwhile, increasing W-D cycles contributed significantly to variations in cohesion and internal friction strength by decreasing the shear strength variables, especially the soil cohesion strength. Correspondingly, soil disintegration was increased during W-D cycles. Furthermore, most degradation of soil structure was recorded within the first two cycles of W-D. The obtained results indicate that the W-D cycles weaken soil structure, increase rainwater infiltration, decrease soil shear strength and disintegration resistance, and accelerate soil erosion. A vicious cycle of granitic slope failure induced by W-D cycles is eventually formed. This study provides useful information about the mechanism of soil mass failure and collapsing gully erosion in granitic hilly slopes. [ABSTRACT FROM AUTHOR]

As one of the most serious soil erosion areas in China, red sandstone erosion areas in southern China have been seriously affected by abundant annual rainfall. To understand the effects of AM fungi and different grass strips on soil erosion characteristics in red sandstone erosion areas in southern China, we selected Cynodon dactylon, Lotus corniculatus, Zoysia japonica, and Astragalus sinicus. Two treatments were carried out for each grass: AM was the soil in its original state, and CK was the soil in which the original AM fungi were eliminated. Taking CK treatment as the control group, any changes of runoff and sediment yield and nutrient loss under different grass strip conditions were measured. The total yield of runoff and sediment in the four grass strips under CK treatment was greater than that of AM. The runoff ammonium nitrogen loss concentration in AM treatment was smaller than in CK treatment under continuous scouring. The ammonium nitrogen loss concentration of sediment during continuous scouring showed a decreasing trend. Under AM treatment, the loss concentration of sediment ammonium nitrogen showed a decreasing trend compared with the CK treatment. The percentage of sediment particles >2 mm in the four grass strips was significantly larger for CK treatment than AM treatment (p < 0.05), and except for Cynodon dactylon, the percentage of sediment particles in the size range of 1–2 mm for other grass strips was significantly larger for CK treatment than for AM treatment (p < 0.05); the percentage of sediment particles at 0.02–0.25 mm was significantly smaller for CK treatment than for AM treatment (p < 0.05). The mean weight diameter (MWD) of sediments produced by the four grass strips under simulated scouring showed an overall increasing trend with increased scouring time. The mean weight diameter (MWD) of sediments produced under CK treatment was larger than that of AM treatment. The fractal dimension (D) of sediments showed a decreasing trend with increased scouring time. These results showed that AM fungi can promote the growth of plant roots, strengthen soil anchoring, protect large particle aggregates in soil under rainfall scouring, and reduce soil erosion and nutrient loss in red sandstone erosion areas in southern China. Cynodon dactylon and Zoysia japonica were more prominent than Lotus corniculatus and Astragalus sinicus in inhibiting soil erosion in red sandstone erosion areas. [ABSTRACT FROM AUTHOR]

Cache attacks exploit the hardware vulnerabilities inherent to modern processors and pose a new threat to Internet of Things (IoT) devices. Intuitively, different cache parameter configurations directly impact the attack effectiveness, but the current research on this issue is not systematic or comprehensive enough. This paper's primary focus is to evaluate how different cache parameter configurations affect access-driven attacks. We build a flexible and configurable simulation verification environment based on the Chipyard framework. To reduce the interference of other factors, we established a baseline for each category of parameter evaluation. We propose a novel evaluation model, called Key Score Scissors Differential (KSSD), for evaluating common private and shared cache parameters under the local and cross-core attack models, respectively; among these are private cache replacement policy, private cache capacity, cache line size, private cache associativity, shared cache capacity, and shared cache associativity. Ours is the first evaluation of the shared cache under a cross-core attack model. As a result of the evaluation, the quantitative metrics can provide a reliable indication of information leakage level under the current cache configuration, which is helpful for attackers, defenders, and evaluators. Furthermore, we provide detailed explanations and discussions of inconsistent findings by comparing our results with the existing literature. [ABSTRACT FROM AUTHOR]

Three-dimensional ground penetrating radar (3D GPR) is a non-destructive examination technology for pavement distress detection, for which its horizontal plane images provide a unique perspective for the task. However, a 3D GPR collects thousands of horizontal plane images per kilometer of the investigated pavement. The existing detection methods using GPR images are time-consuming and risky for subjective judgment. To solve the problem, this study used deep learning methods and 3D GPR horizontal plane images to detect pavement structural distress, including cracks, repairs, voids, poor interlayer bonding, and mixture segregation. In this study, two deep learning methods, called CP-YOLOX and SViT, were used to achieve the aim. A dataset for anomalous waveform localization (3688 images) was first created by pre-processing 3D-GPR horizontal plane images. A CP-YOLOX model was then trained to localize anomalous waveforms. Five SViT models with different numbers of encoders were adopted to perform the classification of anomalous waveforms using the localization results from the CP-YOLOX model. The numerical experiment results showed that 3D GPR horizontal plane images have the potential to be an assistant for pavement structural distress detection. The CP-YOLOX model achieved 87.71% precision, 80.64% mAP, and 33.57 sheets/s detection speed in locating anomalous waveforms. The optimal SViT achieved 63.63%, 68.12%, and 75.57% classification accuracies for the 5-category, 4-category, and 3-category datasets, respectively. The proposed models outperformed other deep learning methods on distress detection using 3D GPR horizontal plane images. In the future, more radar images should be collected to improve the accuracy of SViT. [ABSTRACT FROM AUTHOR]

Respiration rate is an essential vital sign that requires monitoring under various conditions, including in strong electromagnetic environments such as in magnetic resonance imaging systems. To provide an electromagnetically-immune breath-sensing system, we propose an all-fiber-optic wearable breath sensor based on a fiber-tip microcantilever. The microcantilever was fabricated on a fiber-tip by two-photon polymerization microfabrication based on femtosecond laser, so that a micro Fabry–Pérot (FP) interferometer was formed between the microcantilever and the end-face of the fiber. The cavity length of the micro FP interferometer was reduced as a result of the bending of the microcantilever induced by breath airflow. The signal of breath rate was rebuilt by detecting power variations of the FP interferometer reflected light and applying dynamic thresholds. The breath sensor achieved a high sensitivity of 0.8 nm/(m/s) by detecting the reflection spectrum upon applied flow velocities from 0.53 to 5.31 m/s. This sensor was also shown to have excellent thermal stability as its cross-sensitivity of airflow with respect to the temperature response was only 0.095 (m/s)/°C. When mounted inside a wearable surgical mask, the sensor demonstrated the capability to detect various breath patterns, including normal, fast, random, and deep breaths. We anticipate the proposed wearable breath sensor could be a useful and reliable tool for respiration rate monitoring. [ABSTRACT FROM AUTHOR]

Water hammer wave is widely applied to test hydraulic components in various areas. A new hydraulic high-pressure impulse generator is presented in this paper in order to provide the standard water hammer wave for long-term usage. A combination of a sleeve and a rotary spool was used to build the impulse generator, and a booster piston was applied to amplify the output pressure. Mathematical models were established using commercial software, and a prototype and a test rig were built based on the simulation results. The experimental results for both single wave and repeated periods show the feasibility of the new design and indicate that the new hydraulic high-pressure impulse generator can be used for long-time impulse tests. [ABSTRACT FROM AUTHOR]

Leaf senescence is an important agronomic trait that affects both crop yield and quality. In this study, we characterized a premature leaf senescence mutant of wheat (Triticum aestivum L.) obtained by ethylmethane sulfonate (EMS) mutagenesis, named m68. Genetic analysis showed that the leaf senescence phenotype of m68 is controlled by a single recessive nuclear gene. We compared the transcriptome of wheat leaves between the wild type (WT) and the m68 mutant at four time points. Differentially expressed gene (DEG) analysis revealed many genes that were closely related to senescence genes. Gene Ontology (GO) enrichment analysis suggested that transcription factors and protein transport genes might function in the beginning of leaf senescence, while genes that were associated with chlorophyll and carbon metabolism might function in the later stage. Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis showed that the genes that are involved in plant hormone signal transduction were significantly enriched. Through expression pattern clustering of DEGs, we identified 1012 genes that were induced during senescence, and we found that the WRKY family and zinc finger transcription factors might be more important than other transcription factors in the early stage of leaf senescence. These results will not only support further gene cloning and functional analysis of m68, but also facilitate the study of leaf senescence in wheat. [ABSTRACT FROM AUTHOR]

In recent years, two dimensional (2D) hydraulic components have significantly flourished. After a brief development introduction of the 2D pump and 2D flowmeter, it could be concluded that the churning loss, which is caused by the rotational motion of 2D motion-converting mechanisms, has an increasing effect on reducing energy losses. This paper first presents a new 2D motion-converting mechanism and introduces its structure and working principles. To compare it with the former 2D motion-converting mechanism, the same working conditions were applied when designing the new one. Afterward, the generated churning loss by the active parts of the mechanism, such as the new rotor, was well studied by establishing a simplified CFD simulation model and was also verified to have a smaller churning loss than that of the former mechanism. As another key simulation result, the influence of the axial motion of the new rotor was found to be negligible for the churning loss even when the rotational speed was high enough. A test rig was subsequently built up to prove the simulation by monitoring the torque at various rotational speeds. As a result, the churning losses that took place in the new 2D motion-converting mechanism were certainly reduced, and the potential reasons for that were analyzed, as shown in the conclusion section. [ABSTRACT FROM AUTHOR]

A high sensitivity fiber-optic sensor based on self-imaging effect in a hollow-core capillary waveguide (HCCW) is presented for sensing applications. The sensor is composed of a section of HCCW fusion spliced between single mode fibers (SMFs). The self-imaging effect in the HCCW is investigated with different fiber lengths and arc-fusion parameters. By infiltrating the hollow core with index matching liquids, the peak wavelength of the proposed device shifts towards longer wavelengths. The temperature and refractive index (RI) responses of the sensor are studied systematically. When temperature is increased from 25 °C to 75 °C, the temperature sensitivity of the device can be improved significantly with the infiltrated structure, and reaches −0.49 nm/°C, compared with that of the un-filled device, which is 9.8 pm/°C. For the RI response, the liquid-filled structure achieves sensitivity of 12,005 nm/RIU in the range between 1.448 and 1.450, slightly higher than the 11,920 nm/RIU achieved by the un-filled one. The proposed sensor exhibits the advantages of simple structure, high sensitivity and low cost, which may find potential applications in physical and chemical sensing. [ABSTRACT FROM AUTHOR]

DNA N6-methyladenine (6mA) plays an important role in regulating the gene expression of eukaryotes. Accurate identification of 6mA sites may assist in understanding genomic 6mA distributions and biological functions. Various experimental methods have been applied to detect 6mA sites in a genome-wide scope, but they are too time-consuming and expensive. Developing computational methods to rapidly identify 6mA sites is needed. In this paper, a new machine learning-based method, i6mA-DNCP, was proposed for identifying 6mA sites in the rice genome. Dinucleotide composition and dinucleotide-based DNA properties were first employed to represent DNA sequences. After a specially designed DNA property selection process, a bagging classifier was used to build the prediction model. The jackknife test on a benchmark dataset demonstrated that i6mA-DNCP could obtain 84.43% sensitivity, 88.86% specificity, 86.65% accuracy, a 0.734 Matthew's correlation coefficient (MCC), and a 0.926 area under the receiver operating characteristic curve (AUC). Moreover, three independent datasets were established to assess the generalization ability of our method. Extensive experiments validated the effectiveness of i6mA-DNCP. [ABSTRACT FROM AUTHOR]

During various applications in aerospace, ships, autos, and aircraft, 7075 Al alloy will frequently contact other materials, and therefore suffer from slight abrasion. However, the poor tribological properties of 7075 Al alloy greatly affect its performance and life length, leading to limitations in its application. Preparing roughness structures on the surface is regarded as a promising method to improve the properties of materials. However, the tribological properties of 7075 Al alloy cannot be enhanced significantly by roughness structures in complex dynamic changeable environments, owing to the incomplete understanding of the effect of roughness structures. Given the above issues, in this paper, micro-scale structures (linear grooves, gridding grooves, and arc grooves) were designed and prepared on 7075 Al alloy surfaces by a surface treatment (laser micro-engraving), which provides excellent controllability of the morphology and dimensions of as-prepared roughness structures. The tribological properties of the as-prepared surfaces were investigated systemically. The effect of micro-scale structures on the tribological properties was studied. The wear mechanism and tribological properties improvement mechanism of the surfaces were clarified. Furthermore, the effect degree of the enhancement factors of the micro-scale structures on the tribological properties was explored under different conditions. The results indicate that the micro-scale structures play an important role in improving the tribological properties of Al alloy under different sliding speeds. The improvement mechanism can be summarized by four factors. However, the effect degrees of these factors on the tribological properties exhibit considerable differences. This study not only develops specific micro-scale structures that can dramatically improve the tribological properties of 7075 Al alloy under different conditions, but also offers guidance for the construction of appropriate roughness structures that can dramatically improve the tribological properties of Al alloy according to the friction conditions. [ABSTRACT FROM AUTHOR]

Soil aggregate stability is an important aspect of soil function and health. Fertilization could potentially alter soil properties and thereby affect aggregate stability. To determine which fertilizer is useful for improving soil fertility and stabilizing soil aggregates and thereby reducing soil erodibility, we examined three types of fertilizer, and measured how soil organic carbon, carbohydrates, and related soil properties influenced aggregate stability in eroded Ultisols. Treatments included control (CK), mineral fertilizer nitrogen (N), phosphorus (P), potassium (K) (NPK), fertilizer NPK plus straw (NPKS), and farmyard manure (FYM). Aggregate stability was tested according to Le Bissonnais method, involving three disruptive tests: fast wetting (FW), slow wetting (SW), and mechanical breakdown (WS). Total organic carbon, particulate organic carbon, mineral-associated carbon, and cold-water-soluble carbohydrate, hot-water-soluble carbohydrate, and dilute acid hydrolysable carbohydrate were measured, as well as soil intrinsic properties (including pH, bulk density, iron and aluminum oxides). The 12-year fertilization had a larger effect on aggregate stability and related soil properties in a 0–15 cm soil layer, whereas no effect was evident at a soil depth of 15–40 cm. MWD (mean weight diameter) under the three tests decreased with increasing soil depth. Fertilization, especially farmyard manure evidently improved MWDFW and MWDWS at a depth of 0–15 cm. Slaking was the main mechanism of aggregate breakdown in Ultisols studied, followed by mechanical breakdown. Correlation analysis showed that MWDFW and MWDWS at a depth of 0–15 cm increased with the increase of particulate organic carbon, total organic carbon, hot-water-soluble carbohydrate and pH. Furthermore, their interaction with amorphous iron oxides enhanced aggregate stability against slaking or, with amorphous aluminum oxides, modified aggregate stability against mechanical breakdown. Consequently, particulate organic carbon was the dominant cementing agent for aggregation in Ultisols studied, and its combination with pH, amorphous aluminum oxides, amorphous iron oxides, and free aluminum oxides play a synergetic role in stabilizing soil aggregate. Accordingly, farmyard manure or fertilizer NPK plus straw improved soil fertility and the ability to resist slaking. [ABSTRACT FROM AUTHOR]

Surface microstructure preparation offers a promising approach for overcoming the shortcomings of Al alloy, such as poor friction resistance, low hardness and weak corrosion resistance to corrosive liquid. Though many methods for the surface microstructure preparation of Al alloy have been developed, it is difficult for most of the reported methods to regulate the as-prepared microstructure, meaning that the properties of Al alloy cannot be improved efficiently by the microstructure. Thus, the application of microstructure surface of Al alloy and microstructure preparation technology is severely limited. Aimed at this issue, a simple, convenient, high-efficient, low-cost micro-scale roughness structure construction approach that is suitable for engineering application (laser micro-engraving) was developed. The as-prepared microstructure on Al alloy surface formed by laser micro-engraving was investigated systemically. The morphology and formation mechanism of the microstructure were examined. Meanwhile, the effect of laser parameters on morphology, geometrical dimensions and composition of microstructure was investigated. The results indicate that the morphology of microstructure is affected by the overlap degree of molten pool greatly. When each molten pool does not overlap with others, successive individual pits can be constructed. When each molten pool overlaps with others for one time, successive overlapping pits will form. As the overlap degree of the molten pool further increases (overlapping with others for more than one time), the successive pits can become grooved. Because of the influence of laser beam pulse frequency and scanning speed on the diameter and distance of the molten pools, the morphology and geometrical dimensions of microstructure can vary greatly with laser parameters. As the laser beam scanning speed increases, the geometrical dimensions of as-prepared microstructure reduce significantly. In contrast, with the increase of laser beam pulse frequency, the geometrical dimensions change in a complicated manner. However, the chemical composition of microstructure is slightly affected by laser parameters. More importantly, a relationship model was successfully established, which could be used to predict and regulate the geometrical dimensions of microstructure treated by laser micro-engraving. Controllable preparation of microstructure on Al alloy is realized, leading that specific microstructure can be prepared rapidly and accurately instead of suffering from long-time experimental investigation in the future. [ABSTRACT FROM AUTHOR]

Recent decades have witnessed the rapid progress of nanozymes and their high promising applications in catalysis and bioclinics. However, the comprehensive synthetic procedures and harsh synthetic conditions represent significant challenges for nanozymes. In this study, monodisperse, ultrasmall gold clusters with peroxidase-like activity were prepared via a simple and robust one-pot method. The reaction of clusters with H 2 O 2 and 3,3',5,5'-tetramethylbenzidine (TMB) followed the Michaelis-Menton kinetics. In addition, in vitro experiments showed that the prepared clusters had good biocompatibility and cell imaging ability, indicating their future potential as multi-functional materials.

A high sensitivity fiber-optic sensor based on self-imaging effect in a hollow-core capillary waveguide (HCCW) is presented for sensing applications. The sensor is composed of a section of HCCW fusion spliced between single mode fibers (SMFs). The self-imaging effect in the HCCW is investigated with different fiber lengths and arc-fusion parameters. By infiltrating the hollow core with index matching liquids, the peak wavelength of the proposed device shifts towards longer wavelengths. The temperature and refractive index (RI) responses of the sensor are studied systematically. When temperature is increased from 25 °C to 75 °C, the temperature sensitivity of the device can be improved significantly with the infiltrated structure, and reaches -0.49 nm/°C, compared with that of the un-filled device, which is 9.8 pm/°C. For the RI response, the liquid-filled structure achieves sensitivity of 12,005 nm/RIU in the range between 1.448 and 1.450, slightly higher than the 11,920 nm/RIU achieved by the un-filled one. The proposed sensor exhibits the advantages of simple structure, high sensitivity and low cost, which may find potential applications in physical and chemical sensing.

Without requiring targets to carry any device, device-free-based tracking is playing an important role in many emerging applications such as smart homes, fitness tracking, intruder detection, etc. While promising, current device-free tracking systems based on inexpensive commercial devices perform well in the training environment, but poorly in other environments because of different multipath reflections. This paper introduces RDTrack, a system that leverages changes in Doppler shifts, which are not sensitive to multipath, to accurately track the target. Moreover, RDTrack identifies particular patterns for fine-grained motions such as turning, walking straightly, etc., which can achieve accurate tracking. For the purpose of achieving a fine-grained device-free tracking system, this paper builds a trajectory estimating model using HMM (Hidden Markov Model) to improve the matching accuracy and reduce the time complexity. We address several challenges including estimating the tag influenced time period, identifying moving path and reducing false positives due to multipath. We implement RDTrack with inexpensive commercial off-the-shelf RFID (Radio Frequency IDentification) hardware and extensively evaluate RDTrack in a lobby, staircase and library. Our results show that RDTrack is effective in tracking the moving target, with a low tracking error of 32 cm. This accuracy is robust for different environments, highlighting RDTrack's ability to enable future essential device-free moving-based interaction with RFID devices.