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To unceasingly expand the molecular diversity of 1,3,4-oxadiazole-2-carbohydrazides, herein, small fragments (including -CH

Cuboidal permanent magnets (PMs) are commonly used as elementary magnets for most magnetic systems that work by superposition of magnetic forces. This paper proposed a new method that combines the analytical model with the numerical calculation method to calculate the magnetic forces between two cuboidal PMs with parallel and perpendicular magnetization directions. The assumption was that the magnets were ideal with constant and homogeneous magnetizations. The method was also valid for other magnetization directions and any reference points in space, only needed to rotate the coordinate system and give corresponding distance expressions. An important result was that this method had the advantages of high accuracy and low computational cost, enabling rapid studies of the magnetic force characteristics related to magnet positions, geometric dimensions, and magnetic properties, which were easy to calculate by mathematical software, requiring very little running time. Meanwhile, the calculation results have been validated by comparison with the finite element simulation and experimental measurement. The effects of relative positions, dimensions, and magnetic properties on magnetic force characteristics between the two cuboidal PMs have been studied and discussed. Moreover, the improved magnetization distribution on the PM’s surface was made taking the PM’s relative permeability into account, and corresponding results have been given. These results indicated that the proposed method could help for a fast design and optimization of many PM devices that rely on magnetic forces, such as magnetic bearings, magnetic suspensions, magnetic actuators, etc.

Traditional luminescent liquid crystals (LLCs) suffer from fluorescence quenching caused by aggregation, which greatly limits their further application. In this work, a kind of novel LLCs (named carbonized polymer dot liquid crystals (CPD-LCs)) are designed and successfully synthesized through grafting the rod-shaped liquid crystal (LC) molecules of 4'-cyano-4-(4″-bromohexyloxy) biphenyl on the surface of CPDs. The peripheral LC molecules not only increase the distance between different CPDs to prevent them from aggregating and reduce intermolecular energy resonance transfer but also make this LLC have an ordered arrangement. Thus, the obtained CPD-LCs show good LC property and excellent high luminous efficiency with an absolute photoluminescence quantum yield of 14.52% in the aggregated state. Furthermore, this kind of CPD-LC is used to fabricate linearly polarized devices. The resultant linearly polarized dichroic ratio (N) and polarization ratio (ρ) are 2.59 and 0.44, respectively. Clearly, this type of CPD-LC shows promising applications for optical devices.

Magnetic-based driving applications are receiving increasing attention. This study proposed a novel reciprocating permanent magnetic actuator (PMA) to manipulate magnetic micro robots to impact and clear blockages inside fluid pipes in a linear path. The PMA consisted of a cylindrical permanent magnet and a crank slider structure. A straight pipe with a circular cross-sectional area was located in front of the actuator to study the driving performance of PMA. A micro permanent magnet with a cylinder shape was employed as a working robot for manipulation inside the pipe. Firstly, analytical formulas were derived to obtain the magnetic driving force acting on the micro robot and determine the most suitable magnet configuration. The finite element simulation verified the analytical calculation. The developed reciprocating PMA prototype was then introduced, and the PMA and micro robot’s motion performance was analysed. Lastly, preliminary experiments were carried out for evaluating the micro robot’s motion characteristics. Performance tests for different excitation frequencies, flow rates, viscosities, and axial distances, indicating that PMA could manipulate the magnetic micro robot inside the pipe. The results confirmed that the developed PMA could effectively drive the micro robot with the advantage of consecutive magnetic driving. Especially, the micro robot featured good flexibility, rapid response, and a simple structure, suggesting that this micro robot may play an important role in industrial and medical applications, such as blockage elimination and thrombus clearance.

Tropomyosin (TM) is a major shellfish allergen and a minor fish allergen. Different digestion profiles affect potential allergen anaphylaxis of protein. In this study, released peptides of fish-TM, shrimp-TM, and clam-TM by in vitro digestion of simulated gastric fluid (SGF), simulated intestinal fluid (SIF), and gastrointestinal (GI) were analyzed using sequential windowed acquisition of all theoretical fragment ion mass spectra (SWATH-MS) based proteomics. Results showed that digestion products of shrimp-TM yielded a lot of peptides matched T/B cell epitopes while core regions matched epitopes were distributed along the entire chain. Pepsin or trypsin-based digestion products of shrimp-TM presented many more peptides matched T/B cell epitopes compared with those of fish-TM and clam-TM. Besides, a differentiating peptide of VEKDKALSNAEGEVAAL (72-88) overlapped T/B cell epitopes could be used as a candidate peptide marker to identify tropomyosin allergen. These findings would supply new insight into the different allergenicity of tropomyosin.

8 pags., 4 figs., 1 tab., Type-I food allergies are hypersensitive reactions compromising the immune organs and epithelial barriers. To investigate the organ-specific proteomic alterations of the allergy responses, the spleen and intestine of mice sensitized with high (shrimp and clam) and weak (fish) allergenic tropomyosins were analyzed using sequential windowed acquisition of all theoretical fragment ion mass spectra (SWATH-MS)-based proteomics. The results showed that Th1 and Th2 tropomyosin-induced responses in the spleen are characterized by the unique upregulation of innate (cochlin) and adaptive (Ig κ chain V-III region PC 7175) immune regulators, respectively. In the intestine, tropomyosin allergy concurred with the downregulation of 35 differentiating proteins featuring the overall impairment of metabolic pathways, absorption processes and ammonium ion responses. These data provide new functional biomarkers of tropomyosin-induced immune responses as well as candidate targets for intervention., This work was supported by the National Natural Science Foundation of China (grant number 31871719) and by the Spanish Ministry of Science and Innovation (Spanish AEI grant PID2019-103845RB-C21). L. L. Xu was supported by the China Scholarship Council (CSC).

We present a simple hot press-based method for processing La(Fe,Si)13-based compounds consisting of La–Fe–Co–Si–C particles and phenolic resin. The magnetic entropy change ΔS per unit mass for the LaFe10.87Co0.63Si1.5C0.2/phenolic resin compounds have nearly the same magnitude with the base materials. With the content of phenolic resin of 5.0 wt%, the compound conductivity is 3.13 W⋅m−1⋅K−1. In order to measure the cooling performance of La(Fe,Si)13-based compounds, the La(Fe11.6–x Co x )Si1.4C0.15 (x = 0.60, 0.65, 0.75, 0.80, 0.85)/phenolic resin compounds were pressed into thin plates and tested in a hybrid refrigerator that combines the active magnetic refrigeration effect with the Stirling cycle refrigeration effect. The test results showed that a maximum cooling power of 41 W was achieved over a temperature span of 30 K.

Xpert Xpress Flu/RSV is a fast and automated real-time nucleic acid amplification tool for detecting influenza virus and respiratory syncytial virus (RSV). The aim of this study was to verify the accuracy of Xpert Xpress Flu/RSV for detecting influenza virus and RSV. PubMed, EMBASE, Cochrane Library, and Web of Science databases were searched up to October 2020. The quality of the original research was assessed using the Quality Assessment of Diagnostic Accuracy Studies-2 guidelines. Meta-DiSc 1.4 software was used to analyze the sensitivity, specificity, positive likelihood ratio, negative likelihood ratio, diagnostic odds ratio, and summary receiver operating characteristic curve. Deek's funnel plot asymmetry test was used to evaluate the publication bias using the Stata 12.0 software. Ten studies with 25 fourfold tables were included in the analysis. The sensitivity of Xpert Xpress Flu/RSV for detecting influenza A, influenza B, and RSV were 0.97, 0.98, and 0.96, respectively, and the specificities were 0.97, 1.00, and 1.00, respectively. Compared with other common clinical real-time reverse transcription-polymerase chain reaction (RT-PCR), Xpert Xpress Flu/RSV is a valuable tool for diagnosing influenza virus and RSV with high sensitivity and specificity.

To explore the optoelectronic properties of liquid crystalline polymers (LCPs), two luminescent liquid crystalline polymers (LLCPs) with high-efficiency emission in the solid state, namely poly([3-(4′,4′′-dibutyloxy)tetraphenylethylene]styrene) (PSTPE) and poly(3,5-bis[(4′,4′′-dibutyloxy)tetraphenylethylene]styrene) (PS2TPE), on the basis of aggregation-induced emission (AIE) and a “jacketing” effect, are successfully prepared through radical polymerization under mild conditions. The chemical structures of the monomers and polymers are identified via nuclear magnetic resonance (NMR), MALDI-TOF MS and gel permeation chromatography (GPC) characterization. AIE and aggregation-enhanced emission (AEE) behavior are shown by the resulting LLCPs PSTPE and P2STPE, respectively. Meanwhile, the results of wide-angle X-ray diffraction (WAXD) analysis reveal that the LLCPs can form typical smectic phases. More interestingly, both polymers show higher emissive efficiency after thermal annealing. Further, the results of WAXD and ultraviolet-visible (UV-vis) studies indicate that the polymers can form more ordered structures, which means that an increase in ordering can enhance emission.

Tropomyosin (TM) is the major shrimp allergen that could trigger anaphylactic reactions. Recently, recombinant TM (rTM) has been accepted widely in the field of allergen-specific immunotherapy, but the allergenicity of rTM has not been compared with natural TM (nTM) based on an

Neisseria meningitidis is a major cause of bacterial meningitis, and these infections are associated with a high mortality rate. Rapid and reliable diagnosis of bacterial meningitis is critical in clinical practice. However, this disease often occurs in economically depressed areas, so an inexpensive, easy to use, and accurate technology is needed. We performed a pooled-analysis to assess the potential of the recently developed loop-mediated isothermal amplification (LAMP) assay for detection of meningococcus.Pubmed, Embase, and Web of Science were searched to identify original studies that used the LAMP assay to detect meningococcus. After pooling of data, the sensitivity and specificity were calculated, a summary receiver operating characteristic (SROC) curve was determined, and the area under the SROC curve was computed to determine diagnostic accuracy. Publication bias was assessed using Deek's funnel plot.We examined 14 studies within 6 publications. The LAMP assay had high sensitivity (94%) and specificity (100%) in the detection of meningococcus in all studies. The area under the SROC curve (0.980) indicated high overall accuracy of the LAMP assay. There was no evidence of publication bias.The LAMP assay has accuracy comparable to bacterial culture and PCR for detection of meningococcus, but is less expensive and easier to use. We suggest the adoption of the LAMP assay to detect meningococcus, especially in economically depressed areas.

Background Neisseria meningitidis is a major cause of bacterial meningitis, and these infections are associated with a high mortality rate. Rapid and reliable diagnosis of bacterial meningitis is critical in clinical practice. However, this disease often occurs in economically depressed areas, so an inexpensive, easy to use, and accurate technology is needed. We performed a pooled-analysis to assess the potential of the recently developed loop-mediated isothermal amplification (LAMP) assay for detection of meningococcus. Methods Pubmed, Embase, and Web of Science were searched to identify original studies that used the LAMP assay to detect meningococcus. After pooling of data, the sensitivity and specificity were calculated, a summary receiver operating characteristic (SROC) curve was determined, and the area under the SROC curve was computed to determine diagnostic accuracy. Publication bias was assessed using Deek’s funnel plot. Results We examined 14 studies within 6 publications. The LAMP assay had high sensitivity (94%) and specificity (100%) in the detection of meningococcus in all studies. The area under the SROC curve (0.980) indicated high overall accuracy of the LAMP assay. There was no evidence of publication bias. Discussion The LAMP assay has accuracy comparable to bacterial culture and PCR for detection of meningococcus, but is less expensive and easier to use. We suggest the adoption of the LAMP assay to detect meningococcus, especially in economically depressed areas.

Background Chlamydia trachomatis (CT) and Neisseria gonorrhoeae (NG) are widely spread across the world. Asymptomatic or inconspicuous CT/NG infections are difficult to diagnose and treat. Traditional methods have the disadvantages of low detection rate, inaccurate results, and long detection time. However, Xpert CT/NG makes up for the aforementioned shortcomings and has research value and popularization significance. Methods PubMed, Embase, Cochrane Library, and Web of Science were systematically searched, and studies were screened using Xpert CT/NG for diagnosing CT/NG. QUADAS-2 was used to evaluate the quality of the eligible studies. Then, two groups of researchers independently extracted data from these studies. Meta-analyses of sensitivity (SEN), specificity (SPE), positive likelihood ratio (PLR), negative likelihood ratio (NLR), diagnostic odds ratio (DOR), and the area under the curve (AUC) of the summary receiver operating characteristic (SROC) curve were conducted using Meta-DiSc 1.4. Finally, Deek's funnel plots were made using Stata 12.0 to evaluate publication bias. Results 14 studies were identified, and 46 fourfold tables were extracted in this meta-analysis. The pooled SEN, SPE, PLR, NLR, DOR, and AUC in diagnosing CT were 0.94 (95% confidence interval (CI): 0.93–0.95), 0.99 (95% CI: 0.99–1.00), 97.17 (95% CI: 56.76–166.32), 0.07 (95% CI: 0.04–0.12), 1857.25 (95% CI: 943.78–3654.86), and 0.9960, respectively. The pooled SEN, SPE, PLR, NLR, DOR, and AUC in diagnosing NG were 0.95 (95% CI: 0.93–0.96), 1.00 (95% CI: 1.00–1.00), 278.15 (95% CI: 152.41–507.63), 0.08 (95% CI: 0.06–0.12), 4290.70 (95% CI: 2161.78–8516.16), and 0.9980, respectively. Conclusions Xpert CT/NG had high diagnostic sensitivity and specificity for CT and NG. However, more evidence is required to confirm that Xpert CT/NG might serve as the primary method for detecting CT and NG and even the gold standard for diagnosis in the future.

Background Detection of hepatitis B virus (HBV) is vital for the diagnosis of hepatitis B infection. A novel test loop‐mediated isothermal amplification (LAMP) has been successfully applied to detect various pathogens. However, the accuracy of LAMP in diagnosing HBV remains unclear. Therefore, in the present study, the accuracy of LAMP for HBV detection was evaluated systematically. Methods Embase, Cochrane Library, and PubMed databases were searched for studies using LAMP to detect HBV. Then, two researchers extracted data and assessed the quality of literature using the QUADAS‐2 tool independently. I2 statistic and chi‐square test were analyzed to investigate the heterogeneity, and Deek's funnel plot assessed the publication bias. The pooled sensitivity (SEN), specificity (SPE), positive LR (PLR), negative LR (NLR), diagnostic odds ratio (DOR), and 95% confidence intervals were displayed in forest plots. We calculated the area under the curve (AUC) to assess the overall efficiency of LAMP for HBV detection. Results A total of nine studies with 1298 samples were finally included in this evaluation. The pooled sensitivity and specificity of HBV detection were 0.91 (95% CI: 0.89 ~ 0.92) and 0.97 (95% CI: 0.94 ~ 0.99), respectively. The PLR, NLR, and DOR were 16.93 (95% CI: 6.15 ~ 46.55), 0.08 (95% CI: 0.05 ~ 0.14), and 397.57 (95% CI: 145.41 ~ 1087.07). Besides, the AUC was 0.9872, and Deek's plot suggested that there existed publication bias in the studies. Conclusion Compared with PCR, LAMP is a simple, rapid, and effective assay to diagnose HBV. However, additional evidence is essential to confirm that LAMP can replace other methods in diagnosing HBV infection.

Effect of initial pearlite morphology on the microstructure evolution during spheroidization annealing and subsequent hardening treatment was studied in hot-rolled 1.0C–1.5Cr bearing steel. The ferrite-to-austenite transformation in spheroidization annealing can be accelerated by refining the pearlite interlamellar spacing and pearlite colony size. Decreasing interlamellar spacing is also beneficial to increasing the number density of undissolved cementite, leading to the refining of final spheroidized cementite. During the re-austenitizing process of hardening treatment, the smaller initial spheroidized cementite leads to faster cementite dissolution and finer undissolved cementite particles. The prior austenite grain size after hardening treatment can also be decreased by refining the initial pearlite microstructure.

The microstructural evolution and mechanical properties of a low-carbon high-strength bainitic steel under different final cooling temperatures were studied. The microstructures of the experimental steel at different final cooling temperatures were composed of acicular ferrite and granular bainite. A decrease in final cooling temperature resulted in an increase in volume fraction of granular bainite and a decrease in volume fraction of acicular ferrite. The specimen with the lowest final cooling temperature (459 °C) exhibited the highest yield strength, tensile strength, and yield ratio, and a lower total elongation than the specimens with the highest final cooling temperatures (501 and 535 °C) because of the higher volume fraction of granular bainite and finer bainitic ferrite lath. The specimen with the lowest final cooling temperature had a lower absorbed energy than that of the highest final cooling temperature, because the strip-like martensite–austenite (M-A) constituents that existed between the bainitic ferrite or in prior austenite grain boundaries reduced its toughness. At an intermediate final cooling temperature of 501 °C, the experimental steel exhibited excellent mechanical properties with a yield strength, tensile strength, and absorbed energy of 825 MPa, 1232 MPa, and 102 J, respectively.

Lignin has recently attracted much attention as a promising resource to produce fuels and aromatic chemicals. The selective cleavage of C O bond while preserving the aromatic nature has become one of the major challenges in the catalytic valorization of lignin to aromatic chemicals. In this work, we report that the selective reductive cleavage of C O bond in lignin model compounds can be successfully achieved through heterogeneous iron catalysis. The hydrogenolysis of α-O-4 model linkage shows that the iron catalyst prepared by the simultaneous pyrolysis of iron acetate and 1,10-phenanthroline on activated carbon at 800 °C is the most active iron catalyst, affording phenol and toluene with yields of 95% and 90%, respectively. This aromatics selectivity is found to be much higher than that obtained over noble metal catalysts. The presence of N⋯Fe species as the active center of heterogeneous iron catalyst was confirmed by various technologies especially XPS and H2-TPR. For the β-O-4 model linkage, the vicinal OH group was essential for the iron-catalyzed hydrogenolysis of ether linkage. The oxidation of the α-carbon in the β-O-4 model compounds can significantly decrease the bond dissociation energy of ether linkage, giving depolymerization products in moderate to excellent yields.

Using thermo-mechanical control process, the online spheroidization annealing process of 1.0C-1.5Cr bearing steel was designed. Apart from intercritical online spheroidization (IS), a novel subcritical online spheroidization (SS) process was proposed, which is characterized by water-cooling to around 773 K (500 °C) after the final rolling pass, and then directly reheating to 973 K (700 °C) for isothermal holding. Compared with the results from the traditional offline spheroidization (TS) process, the size of spheroidized carbides is similar in both the TS and IS processes, whereas it is much smaller in the SS process. After spheroidization annealing, microstructure evolution during austenitization and quenching treatment was examined. It is shown that the refining of spheroidized carbides accelerates the dissolution of carbides during the austenitizing process, and decreases the size of undissolved carbides. In addition, the SS process can obtain finer prior austenite grain after quenching, which contributes to the enhancement of final hardness.

The microstructural transition and mechanical properties of Fe-Cr-2Ni-Mo-V steel were investigated in a carburizing process with carburizing at 935 °C, oil quenched, re-quenched at 880 °C,and low-temperature tempered at 180 °C. X-ray diffraction was employed for phase analysis and Ir Carbon-sulfur Spectrometer was used for carbon content detection. The morphologies of martensite were observed by scanning electron microscopy. The Vickers hardness was measured and the impact toughness was measured by means of Charpy’s V-notch tests. The results show that the carbon concentration and hardness gradients are established after carburizing process as a function of distance from the case to core. The carbon content gradient results in a gradient of martensitic microstructures, ranging from plate martensitic morphologies with large amounts of retained austenite in case to lath martensitic microstructures with essentially no retained austenite in core. The mechanical properties are significantly improved with adding re-quenching and low-temperature tempering. The case hardness, core hardness, tensile strength and impact energy are 851 HV, 402 HV, 1310 MPa and 92 J, respectively.

Dexamethasone (Dex) and other glucocorticoids are widely used to treat serious infections and immunological diseases, however they may cause steroid‑induced avascular necrosis of the femoral head (SANFH). Salidroside (Sal) has demonstrated an anti‑apoptotic effect on neurocytes by activating the phosphoinositide 3‑kinase (PI3K)/protein kinase B (Akt) signaling pathway. In the present study, primary osteoblasts were used in vitro and in rats in vivo to determine the anti-apoptotic effect of Sal on SANFH. The result of the present study demonstrated that pretreatment with Sal increased the cell survival rate while decreasing the cell apoptosis and lactate dehydrogenase release rate. Additionally, Sal also caused the reduction of TUNEL positive cells in TUNEL staining assay. Sal decreased the expression of cleaved caspase-3, cleaved caspase‑9, apoptosis regulator BAX and cytochrome C, while it increased the expression of B cell lymphoma‑2 and phosphorylated‑Akt in Dex‑induced osteoblasts. In vivo Sal protected against SANFH in rats by decreasing the percentage of empty lacunae. The present study demonstrated that Sal alleviated Dex‑induced osteoblast apoptosis by activating the PI3K/Akt signaling pathway and downregulating caspase‑3 expression in osteoblasts. Sal also protected against SANFH in a rat model of SANFH by decreasing the percentage of empty lacunae. The inhibition of the mitochondrial apoptosis pathway was also involved. Further research is required to determine the full underlying mechanisms by which Sal has an effect.

In order to improve the estimation performance of interacting multiple model tracking algorithm for group targets, the expected-mode augmentation variable-structure interacting multiple model (EMA-VSIMM) and the best model augmentation variable-structure interacting multiple model (BMA-VSIMM) tracking algorithms are presented in this paper. First, by using the EMA method, a more proper expected-mode set has been chosen from the basic model set of group targets, which can make the selected tracking models better match up to the true mode. The BMA algorithm uses a fixed parameter model of different structures to constitute a candidate model set and selects a minimum difference model from target state as the present extended model from the set of candidates at real time. Second, in the filtering process of VSIMM, the fusion estimation of extension state is implemented by the scalar coefficients weighting method, where weight coefficient is calculated by the trace of the corresponding covariance matrix of extension state. The performances of the proposed EMA-VSIMM and BMA-VSIMM algorithms are evaluated via simulation of a generic group targets maneuvering tracking problem.

Gamma Gaussian inverse Wishart probability hypothesis density (GGIW-PHD) filter algorithm is always used for tracking group targets with unknown number and variable measurement rates in the presenc...

A new separation method of guidance instrumentation systematic error of vehicle based on particle swarm optimization (PSO) was proposed. The telemetry environment function matrix is seriously ill-conditioned, which results in the performance degradation of guidance instrumentation systematic error separation. Hereby the problem of guidance instrumentation systematic separation is transformed into an optimization problem and PSO is used to estimate the systematic error coefficients. Furthermore, the guidance instrumentation systematic error is separated from the vehicle trajectory measurement data. The measured data processing results show that the accuracy of the separation of guidance instrumentation systematic error based on PSO is better than that of the traditional Bayesian estimation and principal component estimation methods. The proposed method has practical engineering application value in vehicle test.

An outlier detection and elimination method based on kernel adaptive filtering with variable step size for trajectory data of vehicle test was proposed. The training sample of kernel adaptive filter is designed according to the effective trajectory data. After training, the residual error between the output of the kernel filter and the trajectory can be obtained. If the residual error at some time point is larger than 3 times of the standard deviation of the residual error, the corresponding data point can be considered to be the outlier data based on Wright guidelines, and then the data is instead of the output of the kernel adaptive filter to eliminate the outlier data. To further improve the precision of the outlier data elimination and interpolation, a variable step size algorithm was designed according to the output error of the kernel adaptive filter, in which the step size can be controlled during the iterative process. The proposed method can implement outlier data elimination and interpolation at the same time, which has good robustness and high precision. The simulation and test data processing results show the effectiveness.

Highly ordered hierarchical macroporous-mesoporous alumina with crystalline walls are synthesized by facial route. The general synthesis strategy is based on a sol–gel process associated with block copolymers as soft templates and polystyrene colloidal crystals as hard template to produce macropore and mesopore structures, respectively. Small-angle XRD, TEM and Nitrogen adsorption and desorption results show that hierarchical macroporous-mesoporous alumina possess highly ordered two-dimensional hexagonal mesostructured and highly ordered face centered cubic macropore arrays structure. The present work reveals that the hierarchical macroporous-mesoporous structure can endure high temperature up to 900 °C. FTIR pyridine adsorption measurements show that the amount of Lewis acid sites provided by hierarchical macroporous-mesoporous alumina is nearly two times more than that for mesoporous alumina, indicating that the open macroporous structure may be in favor of the reactant transfer, and the consequently superior activity. Large surface areas, high thermal stability, uniform pore structures and large amounts of surface Lewis acid sites illustrate that these materials are expected to find wide applications in catalysis realm. The highly ordered hierarchical macroporous-mesoporous alumina with crystalline walls are synthesized by a sol–gel process associated with block copolymers as soft templates and polystyrene colloidal crystals as hard template to produce macropore and mesopore structures, respectively.

Thermo-mechanical process and continuous cooling process were carried out on 20CrNi2MoV steel. Three cooling rates were implemented to optimize the mechanical properties. The microstructure evolution, precipitation behavior, and strengthening mechanisms were systematically investigated, and the fracture mechanisms were analyzed via combination of impact fracture morphologies and deflection–load curves. The experimental results indicate that the transformed microstructure of experimental steel is all complex consisting of granular bainitic ferrite and bainitic ferrite with dispersed martensite/austenite (M/A) constituents in the matrix at cooling rates of 13, 21, and 29 °C/s. When the cooling rate increases, the grain of the steel is obviously refined. The sizes of the bainitic ferrite are 5.8, 4.7, and 3.1 μm under cooling rates of 13, 21, and 29 °C/s, respectively. The refinement of the bainitic ferrite plays a dominant role in strength increasing and also contributes to high crack propagation energy. However, the morphologies of M/A constituents obtained under different cooling rates contribute to different crack initiation energies and then affect the impact property.

MicroRNAs (miRNAs) play an important role in many developmental processes and stress responses in plants. In this study, tolerant hot pepper cultivar 'R597' (CaR) and sensitive cultivar 'S590' (CaS) were used to detected differentially expressed miRNAs under high temperatures and high air humidity. The length distribution of obtained small RNAs was significantly different between libraries. There were a total of 71 miRNA families identified in two genotypes, and 24 conserved miRNA families were detected in all four sRNA libraries. MIR166, MIR156/157, MIR167, MIR168, MIR2118, and MIR5301 were highly expressed in four libraries, and 93 miRNAs had a species-specific expression. Among them, 60 miRNAs were preferentially expressed in S590 leaves and 33 miRNAs were preferentially expressed in R597 leaves. Mostly miRNAs were less-conserved miRNAs. The most abundant miRNAs with different expressions between two pepper species was miR6149b, which exhibited a high level (read count 42,443) in CaSCK but no expressed in CaRCK. We found 650 (CaRCK), 1054 (CaRHH), 914 (CaSCK), 1045 (CaSHH) potential targets for 92 (CaRCK), 124 (CaRHH), 128 (CaSCK), 117 (CaSHH) hot pepper miRNAs, respectively. These findings facilitate in better understanding of the molecular mechanism underlying high temperature and high air humidity condition in different pepper genotypes.

Laser surface quenching was conducted on the 1.0C-1.5Cr steel with different initial microstructures. The effects of initial microstructure on the cementite dissolution and grain size were studied, and the distributions of temperature and stress were simulated. The results indicated that the thickness of hardened layer was larger when the initial microstructure is martensite, which is mainly because the martensite-to-austenite transformation is displacive transformation during laser heating. Within hardened layer, the volume fraction of cementite (VFC) increases with the increase of depth. For the initial microstructure composed of ferrite matrix and cementite, the refining of cementite will facilitate its dissolution, and within hardened layer, mean diameter of cementite (MDC) decreases first and then increases with the increase of depth. For the initial microstructure composed of martensite matrix and cementite, the MDC changes slightly at deeper position of hardened layer. Tensile stress will form in the heat affect zone, and due to the high sensitivity to tensile stress, the impact resistance and bending properties of spheroidized microstructure are worse after laser surface quenching. Under identical laser parameters, the impact absorbed energy of spheroidized microstructure is about 50% of tempered sorbite and 60% of martensitic microstructure, and its bending strength is about 60% of tempered sorbite, and 40% of martensitic microstructure. The impact absorbed energy can be increased by at least 26% through preheating at 160 °C. In addition, the refining of initial martensitic microstructure will enhance bending resistance.