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Abstract: Purine, one of the nucleotides, is an important substance for the metabolism and regulation of the body. Purine plays a key role not only in the composition of coenzymes but also in the supply of energy. Since purine was artificially synthesized, it has always been an important scaffold for respiratory diseases, cardiovascular diseases, and anti- tumor and anti-viral drugs. In addition to being widely used as competitive antagonists in the treatment of diseases, purines can be used in combination with other drugs and as precursors to benefit human life. Unfortunately, few new discoveries have been made in recent years. In this article, purine drugs in the market have been classified according to their different targets. In addition, their mechanism of action and structure-activity relationship have also been introduced. This paper provides details of the signaling pathways through which purine drugs can bind to the respective receptors on the surface of cells and cause consequent reactions within the cell, which finally affect the targeted diseases. The various receptors and biological reactions involved in the signaling for respective disease targets within the cells are discussed in detail.

To explore the effects of high cervical spinal cord electrical stimulation (cSCS) on the recovery of neurological function and its possible mechanism in rats with traumatic brain injury (TBI). 72 rats were randomly divided into: (1) a sham group; (2) a traumatic brain injury (TBI) group; (3) a TBI+cSCS group; (4) a LY294002+TBI+cSCS group. The degree of neurological dysfunction was evaluated by modified Neurological severity score (mNSS). The pathological changes of the brain tissue in the injured area were observed by HE staining, and the apoptosis of neuron cells were observed by TUNEL staining. The expressions of BDNF and VEGFmRNA were detected by polymerase chain reaction (PCR), and the expressions of p-AKT, AKT, Bcl-2, Bax and caspase-3 proteins were detected by western blot. Compared with that of the TBI and LY294002+TBI+cSCS groups, the mNSS of the TBI+cSCS group were significantly lower on day 3 and 7 ( P0.05). Compared with that in the TBI and LY294002+TBI+cSCS groups, the apoptosis of neuron cells in the TBI+cSCS group decreased significantly ( P0.05). Compared with the TBI and LY294002+TBI+cSCS group, the expression of Bcl-2 protein increased and the expressions of Bax and Caspase-3 proteins decreased in the TBI+cSCS group ( P0.05). Compared with that in the TBI and LY294002+TBI+cSCS groups, the intensity of p-Akt/Akt in the TBI+cSCS group increased ( P0.05). We found that cSCS had a protective effect on neuron cells after craniocerebral injury and could improve neurological dysfunction in rats, the mechanism of which might be that cSCS made the PI3K/Akt pathway more active after TBI.

The thermal stability and mechanical properties of a gradient-nanograined structure (GNS) CoCrNi medium entropy alloy (MEA) processed by ultrasonic surface rolling were studied by using isothermal/isochronal annealing tests combined with quasi-in-situ electron backscatter diffraction (EBSD) characterization and Vickers micro-hardness (HV) measurements. A layer by layer high-throughput investigation method was used to quantitatively study the grain growth kinetics and grain boundary evolution with different initial grain sizes, which could effectively save specimen and time costs. The grain nucleation and growth, as well as shrink and disappearance process through Σ3 coincidence site lattice boundary migration with slightly lattice rotation during annealing were directly revealed. The layer by layer grain growth kinetics and calculated activation energy indicate that the thermal stability of nano-grained top surface layer is relatively higher than that of nano-twined subsurface layer for the gradient CoCrNi MEA processed by ultrasonic surface rolling. Further analysis show that the grain boundary relaxation and dynamic recrystallization of the topmost nano-grains led to the decrease of grain boundary energy, thus improving their thermal stability. The present work provided theoretical basis for the application of CoCrNi MEA at high temperatures. Moreover, the high-throughput method on the investigation of grain stability by using gradient structure can be easily extended to other materials and it is of great significance for understanding the microstructural evolution of gradient materials.

Abstract: Familial hypercholesterolemia (FH) is an autosomal dominant inheritable disease with severe disorders of lipid metabolism. It is mainly marked by increasing levels of plasma total cholesterol (TC) and low-density lipoprotein cholesterol (LDL-C), xanthoma, corneal arch, and early-onset coronary heart disease (CHD). The prevalence of FH is high, and it is dangerous and clinically underdiagnosed. The clinical treatment for familial hypercholesterolemia includes both pharmacological and non-pharmacological treatment, of which non-pharmacological treatment mainly includes therapeutic lifestyle change and dietary therapy, LDL apheresis, liver transplantation and gene therapy. In recent years, many novel drugs have been developed to treat familial hypercholesterolemia more effectively. In addition, the continuous maturity of non-pharmacological treatment techniques has also brought more hope for the treatment of FH. This paper analyzes the pathogenic mechanism and the progress in clinical treatment of familial hypercholesterolemia. Furthermore, it also summarizes the mechanism and structure-activity relationship of FH therapeutic drugs that have been marketed. In a word, this article provides a reference value for the research and development of FH therapeutic drugs.

A highly precise and timely diagnosis technology can help effectively monitor and adjust the sucker rod production system (SRPS) used in oil wells to ensure a safe and efficient production. The current diagnosis method is pattern recognition of a dynamometer card (DC) based on feature extraction and perceptron. The premise of this method is that the training and target data have the same distribution. However, the training data are collected from a field SRPS with different system parameters designed to adapt to production conditions, which may significantly affect the diagnostic accuracy. To address this issue, in this study, an improved model of the sucker rod string (SRS) is derived by adding fault-parameter dimensions, with which DCs under 16 working conditions could be generated. Subsequently an adaptive diagnosis method is proposed by taking simulated DCs generated near the working point of the target SRPS as training data. Meanwhile, to further improve the accuracy of the proposed method, the DC features are improved by relative normalization and using additional features of the DC position to increase the distance between different types of samples. The parameters of the perceptron are optimized to promote its discriminability. Finally, the accuracy and real-time performance of the proposed adaptive diagnosis method are validated using field data.

Abstract: According to the 2017 ILAE's official definition, epilepsy is a slow brain disease state characterized by recurrent episodes. Due to information released by ILAE in 2017, it can be divided into four types, including focal epilepsy, generalized epilepsy, combined generalized, and focal epilepsy, and unknown epilepsy. Since 1989, 24 new antiepileptic drugs have been approved to treat different types of epilepsy. Besides, there are a variety of antiepileptic medications under clinical monitoring. These novel antiepileptic drugs have plenty of advantages. Over the past 33 years, there have been many antiepileptic drugs on the mearket, but no one has been found that can completely cure epilepsy. In this paper, the mentioned drugs were classified according to their targets, and the essential information, and clinical studies of each drug were described. The structure-activity relationship of different chemical structures was summarized. This paper provides help for the follow-up research on epilepsy drugs.

Ischemic stroke leads to severe neurological dysfunction in adults. Hyperbaric oxygen (HBO) induces tolerance to cReperfusion inj/reperfusion (I/R) injury. Therefore, our aims were to investigate whether SIRT1 participates in regulatingin the neuro-protective effect of HBO in a cerebral I/R model and its mechanism. Mice N2a cells were used to construct an oxygen deprivation/reperfusion (OGD/R) model to simulate in vitro brain I/R injury and to evaluate the role of HBO in OGD/R stimulated cells. Cell proliferation was detected using MTT, and apoptosis was determined by flow cytometry. ELISA was used to measure the concentration of TNF-α, IL-1β and IL-6 related inflammatory factors. RT-qPCR and western blot assays were performed to test the expression of SIRT1. Immunoprecipitation was used to detect acetylation of HMGB1. Expression of SIRT1 was obviously reduced after OGD/R treatment in N2a cells, while SIRT1 was obviously enhanced in HBO treated cells. Moreover, knockdown of SIRT1 induced neuro-inflammation damage in cells and HBO effectively improved the inflammatory response in OGD/R treated cells by affecting SIRT1 levels. Furthermore, HBO induced the deacetylation of HMGB1 via regulating SIRT1. Interestingly, HBO via regulating the SIRT1-induced HMGB1 deacetylation and suppressing MMP-9 improved ischemic brain injury. HBO regulated ischemic brain injury via regulation of SIRT1-induced HMGB1 deacetylation, making it a potential treatment for ischemic brain injury treatment.

The microstructural evolution and mechanical properties of ultrafine-grained (UFG) CP-Ti after an innovative large-volume equal channel angular pressing (L-ECAP) and multi-directional forging (MDF) were systematically examined using monotonic tensile tests combined with transmission electron microscope (TEM) and electron backscatter diffraction (EBSD) techniques. Substantially refined and homogeneous microstructures were achieved after L-ECAP (8-pass and 12-pass) and MDF (2-cycle and 3-cycle), respectively, where the grain size distribution conformed to lognormal distribution. The grain refinement of 450 °C L-ECAP is dominated by dynamic recrystallization (DRX) and dynamic recovery (DRV), while that of MDF is dominated by DRX. The iron impurities promote recrystallization by pinning-induced dislocation accumulation so that DRX is prone to occur at iron segregation regions during L-ECAP. The monotonic tensile results show that the strain hardening rate of CP-Ti increases with the decrease of grain size, while the continuous strain hardening ability decreases. The relationship between the average grain size and yield strength is in accordance with Hall-Petch relationship. Meanwhile, the individual strengthening mechanisms were quantitatively examined by the modified model. The results indicate that the strengthening contribution of dislocation accumulation to yield strength is greater than that of grain refinement.

Optical needle has become a hot research topic in recent years, due to the excellent properties and potential applications. To achieve a sub-diffraction optical needle, there are three common methods including planar diffractive lenses, reflective mirrors or axicons, and high-NA objective lenses with the designed phase or amplitude elements. Here, we propose a new kind of designed phase and amplitude element called the sinusoidal-amplitude binary phase mask (SA-BPM), which modulates the amplitude and phase distributions of the incident vector optical fields (VOFs) simultaneously. Based on Richards-Wolf vector diffraction integral, the corresponding parameters of SA-BPM and the optimal optical needle length are calculated by exhaustive method and genetic algorithm. We further upgrade the SA-BPM by adding a Gaussian function in the amplitude modulation, and design the Gaussian SA-BPM (GSA-BPM). We find that the ultra-long optical needles are achieved with the SA-BPM and GSA-BPM, and the depth of focus of the optical needles are improved by 30%–70% compared with the case of binary phase mask. Such SA-BPM and GSA-BPM we proposed have great potential for manipulation and utilization of the ultra-long optical needles.

Qi-Lin pill (QLP) is an effective traditional Chinese medicine prescription (TCMP) that has been used for the treatment of the oligoasthenozoospermia in China. Recently, some articles described the pharmacological effects of QLP and multiple ingredients in QLP contribute to its effects. However, the pharmacokinetic and target tissue distribution data of QLP are still unknown. In the present study, according to the Bioanalytical Method Validation Guidance of FDA, a sensitive and selective UPLC-MS/MS method was developed and validated for simultaneous determination of multiple constituents in rat plasma and testicular tissue, including morusimic acid A, codonopyrridium B, magnoflorine, emodin, 2,3,5,4'-tetrahydroxystilbene-2-O-β-D-glucoside (THSG), ecliptasaponin A, paeoniflorin, albiflorin, gallic acid, danshensu, salvianolic acid A, catechin, isosinensetin, nobiletin, formononetin, calycosin, icariside II, icariin and epimedin C. For 19 analytes, the LLOQs reached 0.01-4 ng/mL. And all calibration curves showed favorable linearity (r ≥ 0.9903) in linear ranges. The intra-day and inter-day precision (relative standard deviation) for all analytes was less than 14.92 %, and the accuracies (as relative error) were in the range of - 6.44 % to 6.22 %. Extraction recoveries and matrix effects of analytes and IS were acceptable. All analytes were stable during the assay and storage in plasma samples. The method was successfully applied for the pharmacokinetics and testis distribution of multiple chemical constituents in QLP after a single oral dose. As a result, high exposure of danshensu, gallic acid, paeoniflorin and albiflorin were observed in rat plasma and testicular tissue. Among the flavonoids, isosinensetin and nobiletin had high exposure in testicular tissue. Moreover, alleviation of progesterone reduction was evaluated in H

Motivation During lead compound optimization, it is crucial to identify pathways where a drug-like compound is metabolized. Recently, machine learning-based methods have achieved inspiring progress to predict potential metabolic pathways for drug-like compounds. However, they neglect the knowledge that metabolic pathways are dependent on each other. Moreover, they are inadequate to elucidate why compounds participate in specific pathways. Results To address these issues, we propose a novel Multi-Label Graph Learning framework of Metabolic Pathway prediction boosted by pathway interdependence, called MLGL-MP, which contains a compound encoder, a pathway encoder and a multi-label predictor. The compound encoder learns compound embedding representations by graph neural networks. After constructing a pathway dependence graph by re-trained word embeddings and pathway co-occurrences, the pathway encoder learns pathway embeddings by graph convolutional networks. Moreover, after adapting the compound embedding space into the pathway embedding space, the multi-label predictor measures the proximity of two spaces to discriminate which pathways a compound participates in. The comparison with state-of-the-art methods on KEGG pathways demonstrates the superiority of our MLGL-MP. Also, the ablation studies reveal how its three components contribute to the model, including the pathway dependence, the adapter between compound embeddings and pathway embeddings, as well as the pre-training strategy. Furthermore, a case study illustrates the interpretability of MLGL-MP by indicating crucial substructures in a compound, which are significantly associated with the attending metabolic pathways. It is anticipated that this work can boost metabolic pathway predictions in drug discovery. Availability and implementation The code and data underlying this article are freely available at https://github.com/dubingxue/MLGL-MP.

Purine, one of nucleotide, is an important substance for metabolism regulation of the body. Purine plays a key role not only in the composition of coenzymes but also in the supply of energy. Since purine was artificially synthesized, it has always been an important scaffold for respiratory diseases, cardiovascular diseases, and anti-tumor and anti-viral drugs. In addition to being widely used as competitive antagonists in the treatment of diseases, purines can be used in combination with other drugs and as precursors to benefit human life. Unfortunately, few new discoveries have been made in recent years. In this article, purine drugs on the market have been classified according to their different targets. In addition, their mechanism of action and structure-activity relationship have been also introduced. This paper provides details of the signaling pathways from when the purine drugs bind to the respective receptors on the surface of cells and the consequent reactions within the cell which finally affect the targeted diseases. The various receptors and biological reactions involved in the signaling for respective disease targets within the cells are discussed in detail.

BACKGROUND The Angong Niuhuang pill (ANP) has been widely used in the adjuvant treatment of patients with traumatic brain injury (TBI). However, the efficacy and adverse reactions of this drug are controversial. In this study, it was aimed to evaluate the effectiveness and safety of ANP on patients with TBI by a systematic review and meta-analysis of randomized controlled trials (RCTs). METHODS PubMed, Embase, Cochrane Library, Chinese Biomedicine Database (CBM), China National Knowledge Infrastructure (CNKI), Chinese Scientific Journals Database (VIP), and Wangfang databases were systematically searched from their establishment until June 2020. RCTs of ANP treating TBI were enrolled. Odds risk (OR) was used to assess the total effective rate and safety and mean difference (MD) and 95% confidence interval (CI) were used to assess the quantitative data. Tthe included literature's quality was evaluated by RevMan 5.3. The sensitivity and publication bias was evaluated by Stata 16.0. RESULTS Twelve studies were identified in this systematic review, including 1,568 participants. The metaanalysis results suggested that ANP combined with routine treatment obviously improved the postoperative GCS [MD =1.97, 95% CI (1.22, 2.72), P

Abstract The post-dynamic recrystallization behavior of ultrafine-grained (UFG: 0.44 μm) cp-Ti under annealing, room temperature (RT) monotonic and cyclic loading was investigated across a range of temperatures and deformation rates wherever appropriate. By characterizing the grain and boundary structures, it was confirmed that recrystallization and grain growth occurred due to annealing (≥ 600 °C) and R = − 1 fatigue at RT. There was a noticeable 30 deg aggregation in misorientation distribution, along with the increased grain size. However, the hypothetical correlation between 30 deg aggregation and Σ13a or the other characteristic coincidence site lattice boundaries was found to be weak. The fatigue-induced grain growth is particularly intriguing for two reasons. First, the large monotonic deformation with low strain rate cannot trigger grain growth. Second, fatigue sharpened the basal intensity around the ND and caused a weaker texture component close to TD (load axis along the LD, perpendicular to the TD–ND plane). By contrast, high-temperature annealing only strengthened the UFG processing induced basal pole but without affecting its location. Novel insights into this fatigue-induced texture evolution in UFG cp-Ti has been provided. The lattice rotation during fatigue can be attributed to the combined effect of activation of prismatic $$ \langle a\rangle $$ ⟨ a ⟩ slip parallel to LD, and basal $$ \langle a\rangle $$ ⟨ a ⟩ slip perpendicular to it. The theoretically calculated stress to activate dislocation slip by assuming a non-equilibrium grain boundary state lent support to the above assertion. Moreover, the TEM observation evidently showed the characteristics of dislocation cross-slip and multiple slip in the grain interior. Graphical Abstract

Codonopsis radix was commonly used as food materials or herbal medicines in many countries. However, the comprehensive analysis of chemical constituents, and in vivo xenobiotics of Codonopsis radix remain unclear. In the present study, an integrated strategy with feature-based molecular networking using ultra-high-performance liquid chromatography coupled with mass spectrometry was established to systematically screen the chemical constituents and the in vivo xenobiotics of Codonopsis radix. A step-by-step manner based on a composition database, visual structure classification, discriminant ions, and metabolite software prediction was proposed to overcome the complexities due to the similar structure of chemical constituents and metabolites of Codonopsis radix. As a result, 103 compounds were tentatively characterized, 20 of which were identified by reference standards. Besides, a total of 50 xenobiotics were detected in vivo, including 26 prototypes and 24 metabolites, while the metabolic features of the pyrrolidine alkaloids were elucidated for the first time. The metabolism reactions of pyrrolidine alkaloids and sesquiterpene lactones included oxidation, methylation, hydration, hydrogenation, demethylation, glucuronidation, and sulfation. This study provided a generally applicable approach to the comprehensive investigation of the chemical and metabolic profile of traditional Chinese medicine and offered reasonable guidelines for further screening of quality control indicators and pharmacodynamics mechanism of Codonopsis radix.

The present study explored the mechanism of Fagopyri Dibotryis Rhizoma(FDR) and its main active components in the treatment of acute lung injury(ALI) based on the network pharmacology and the in vitro experiments. The main active components of FDR were obtained from the TCMSP database and screened by oral bioavailability and drug-likeness. The related target proteins of FDR were retrieved from the PubChem database, and the target genes related to ALI were screened out from the GeneCards database. A protein-protein interaction(PPI) network of compound target proteins and ALI target genes was constructed using STRING 11.0. Ingenuity Pathway Analysis(IPA) platform was used to analyze the common pathways of the potential compound target proteins of FDR and ALI target genes, thereby predicting the key targets and potential signaling pathways of FDR for the treatment of ALI. Finally, the potential pathways and key targets were verified by the in vitro experiments of lipopolysaccharide-induced RAW264.7 cells intervened by epicatechin(EC), the active component of FDR. The results of network pharmacology showed that 15 potential active components such as EC, procyanidin B1, and luteolin presumedly functioned in the treatment of ALI through nuclear transcription factor-κB(NF-κB) signaling pathway, transforming growth factor-β(TGF-β) signaling pathway, and adenosine 5'-monophosphate(AMP)-activated protein kinase(AMPK) signaling pathway through key targets, such as RELA(P65). The results of in vitro experiments showed that 25 μmol·L~(-1) EC had no toxicity to cells and could inhibit the expression of the p65-phosphorylated protein in the NF-κB signaling pathway to down-regulate the expression of downstream inflammatory cytokines, including tumor necrosis factor-α(TNF-α), IL-1β and nitric oxide(NO), and up-regulate the expression of IL-10. These results suggested that the therapeutic efficacy of FDR on ALI was achieved by inhibiting the phosphorylation of p65 protein in the NF-κB signaling pathway and down-regulating the level of proinflammatory cytokines downstream of the signaling pathways.

Aim. To investigate the protective effects of budesonide against lipopolysaccharide- (LPS-) induced acute lung injury (ALI) in a murine model and its underlying mechanism.Methods. Adult male C57BL/6 mice were divided into three groups: control, ALI, and ALI + budesonide groups. LPS (5 mg/kg) was intratracheally injected to induce ALI in mice. Budesonide (0.5 mg/kg) was intranasally given 1 h before LPS administration in the ALI + budesonide group. Twelve hours after LPS administration, all mice were sacrificed. Hematoxylin-eosin staining and pathological scores were used to evaluate pathological injury. Bronchoalveolar lavage was performed. The numbers of total cells, neutrophils, and macrophages in the bronchoalveolar lavage fluid (BALF) were counted. Enzyme-linked immunosorbent assay was employed to detect the proinflammatory cytokines in BALF and serum, including tumor necrosis factor- (TNF-)α, monocyte chemoattractant protein- (MCP-) 1, and interleukin- (IL-) 1β. The expression of the nucleotide-binding oligomerization domain-like receptor family, pyrin domain-containing 3 (NLRP3) inflammasome was detected by western blotting. A lethal dose of LPS (40 mg/kg, intraperitoneally) was injected to evaluate the effects of budesonide on survival rates.Results. Budesonide pretreatment dramatically attenuated pathological injury and reduced pathological scores in mice with ALI. Budesonide pretreatment obviously reduced the numbers of total cells, neutrophils, and macrophages in the BALF of mice with ALI. Additionally, budesonide dramatically reduced TNF-αand MCP-1 expression in the BALF and serum of mice with ALI. Budesonide significantly suppressed NLRP3 and pro-caspase-1 expression in the lung and reduced IL-1βcontent in the BALF, indicating that budesonide inhibited the activation of the NLRP3 inflammasome. Furthermore, we found that budesonide improved the survival rates of mice with ALI receiving a lethal dose of LPS.Conclusion. Suppression of NLRP3 inflammasome activation in mice via budesonide attenuated lung injury induced by LPS in mice with ALI.

Subarachnoid hemorrhage (SAH) is a fatal stroke caused by bleeding in the brain. SAH can be caused by a ruptured aneurysm or head injury. One-third of patients will survive and recover. One-third will survive with disability; one-third will die. The focus of treatment is to stop bleeding, restore normal blood flow, and prevent vasospasm. Treatment for SAH varies, depending on the bleeding’s underlying cause and the extent of damage to the brain. Treatment may include lifesaving measures, symptom relief, repair of the bleeding vessel, and complication prevention. However, the useful diagnostic biomarkers of SAH are still limited due to the instability of gene marker expression. To overcome this limitation, we developed a new protocol pairing genes and screened significant gene pairs based on the feature selection algorithm. A classifier was constructed with the selected gene pairs and achieved a high performance.

Sulfurized polyacrylonitrile (S@pPAN) is a promising cathode material for next-generation batteries due to its high stable cycle performance. However, challenges remain in achieving larger capacity and higher discharge voltage, it is therefore of vital significance to illustrate the electrochemical reaction mechanism of S@pPAN or similar materials. Herein, we present conjugate double-bond lithium-ion storage mechanism by solid-state NMR and XPS. During discharge, besides the reaction between sulfur and lithium, the C=N and C=C groups can also react with lithium to form Li-C-N-Li and Li-C-C-Li and afford capacity, resulting a higher practical discharge capacity than the theoretical capacity of elemental sulfur. This electrochemical reaction mechanism provides a new idea for the new energy materials with high capacity.

With fractal amplitude masks of the Sierpinski carpet and Sierpinski triangle, we theoretically and experimentally present the diffraction properties and applications of spatially structured optical fields, including the vector optical field, vortex optical field, and vortex vector optical field. The diffraction patterns of the vector optical fields exhibit self-similarity, and the characteristics of the vector optical fields are maintained in every diffraction peak. The diffraction patterns of the vortex optical fields and vortex vector optical fields exhibit triangular lattice arrays, and the vortex topological charge can be determined by the number of peak spots in the triangular lattice array. We hope these diffraction properties with fractal amplitude masks can be applied not only in detecting topological charges of spatially structured optical fields, but also in generating flexibly controlled diffraction patterns and lattice arrays, which may be useful in optical machining, optical trapping, and information transmission.

The optical needle generated by a tightly focused vector optical field (VOF) has attracted wide attention and been applied in various areas. In previous research, two typical kinds of VOFs were generally used to generate optical needles, including radially polarized VOF (RP-VOF) and vortex azimuthally polarized VOF (VAP-VOF). Here, we propose a new kind of duplex VOF that is designed by arranging the RP-VOF and VAP-VOF in concentric belts. With the help of a binary phase mask, the optical needle of the tightly focused duplex VOF is much longer than that generated by the two conventional VOFs. The optical needle has a three-section polarization distribution, as the longitudinal component is dominant in the center, while the transverse components are at two ends along the longitudinal axis, which is different from a purely transversely polarized optical needle and optical needle with a dominant longitudinal component. Furthermore, a parabolic hybrid mask (PHM) is proposed, which can improve the length of the optical needle for the duplex VOF, RP-VOF, and VAP-VOF. When applying the duplex VOF and PHM simultaneously, an ultra-long optical needle can be achieved. The duplex VOF and PHM we propose are superior relative to other VOFs and masks in terms of generating ultra-long optical needles, which can be used in areas including optical detection, high-density storage, super-resolution imaging, and nano lithography.

A series of strain-controlled creep-fatigue tests with various dwell times and strain ratios are carried out on a nickel-based superalloy at 650 °C. Aiming at the mechanical understanding of creep-fatigue behavior, a non-unified constitutive framework is used to describe macroscopic cyclic deformation process to understand creep-fatigue behavior. Afterward, the quantitative evaluation of creep-fatigue damage is quantitatively determined by the cycle-by-cycle strain energy density exhaustion (SEDE) approach. The effects of strain ratio and dwell time on creep-fatigue life endurances can be well revealed by the proposed life model, where all the data points are predicted within ± 1.5 error band. Particularly, life prediction capacities with long dwell times are further improved based on three-regime creep mechanism.

A large number of strain-controlled creep-fatigue tests under wide loading waveforms are conducted at 650 ℃ in nickel-based forged GH4169 superalloy. Comprehensive characterizations, including scanning electron microscope (SEM), electron backscatter diffraction (EBSD) and transmission electron microscope (TEM), are observed from the post-test examinations. Particular focus is brought to the physical understanding of damage mechanisms under wide creep-fatigue loading conditions using EBSD analysis. The representative misorientation parameters are calculated for constructing diffraction-based misorientation mapping. Semi-quantitative analysis of longitudinal EBSD observations is conducted to prove that strain ratio has little influence on creep-fatigue damage degrees, while dwell time causes noticeable changes to damage progressions. In particular for geometrically necessary dislocation (GND) map explored in this work, more fundamental information based on failure physics is obtained to analyze the creep-fatigue crack initiation mechanism.

Rotary-bending fatigue tests of Ti-6Al-4V alloy at very high-cycle regime were performed in air and 3.5% NaCl solution, respectively. The S-N curves exhibited the characteristic of horizontal asymptote (traditional fatigue limit) in laboratory air, while a lower fatigue limit was shown in 3.5% NaCl solution after around 3 × 108 cycles. The decrease of fatigue life was due to the generation of small surface defects in comparison with that in air. These defects were ascribed to the hydrogen-induced cracking and fatigue loading. The number of fatigue crack initiation sites decreases with increasing cycles. Only one crack origin site, dominated by slip mechanism, exists in each specimen at very high-cycle regime. The existing experimental S-N data of Ti-6Al-4V alloy from very high-cycle fatigue tests were also reviewed. It was shown that the fatigue life (R = −1) of Ti-6Al-4V alloy was predominantly influenced by the microstructure and not strongly sensitive to the loading mode and frequency (in the range from 52.5 Hz to 20 kHz) under air condition at room temperature.

Two new bis-Schiff bases containing a piperazine ring, N,N‘-bis(4-chlorobenzylidene)- and N,N‘-bis(4-cyanobenzylidene)-1,4-bis(3-aminopropyl)piperazine, were prepared by the reaction of N,N‘-bis(3-aminopropyl)piperazine with 4-chloro- and 4-cyanobenzaldehyde, respectively. The dichloro compound was fully identified by X-ray crystallography and it exhibited good antibacterial activity against Escherichia coli, Staphylococcus aureus and Bacillus subtilis.

In this study, a novel modifier (PPD-PTES) for Magnesium Hydroxide (MH) was successfully synthesized from (3-Aminopropyl) triethoxysilane and phenylphosphonic dichloride aiming to improve not only the compatibility of MH with polymer but also its efficiency. Fourier transform infrared spectroscopy (FTIR), 1H, 31P-nuclear magnetic resonance (NMR) were carried out to characterize its structure. The flammability, thermal degradation and mechanical properties of the PLA/MH composites were investigated by limiting oxygen index (LOI), microscale combustion calorimetry (MCC), thermogravimetric analysis (TGA) and tensile test. The results showed that the introduction of MH can significantly reduce the peak of heat release rate (PHRR) and total heat release (THR). Additionally, the LOI of modified MH reinforced PLA has also increased compared to the unmodified MH reinforced PLA. Further, results of tensile test proofed that the organic modification could improve the compatibility of MH with the polymer, but only slightly decrease brittleness.In this study, a novel modifier (PPD-PTES) for Magnesium Hydroxide (MH) was successfully synthesized from (3-Aminopropyl) triethoxysilane and phenylphosphonic dichloride aiming to improve not only the compatibility of MH with polymer but also its efficiency. Fourier transform infrared spectroscopy (FTIR), 1H, 31P-nuclear magnetic resonance (NMR) were carried out to characterize its structure. The flammability, thermal degradation and mechanical properties of the PLA/MH composites were investigated by limiting oxygen index (LOI), microscale combustion calorimetry (MCC), thermogravimetric analysis (TGA) and tensile test. The results showed that the introduction of MH can significantly reduce the peak of heat release rate (PHRR) and total heat release (THR). Additionally, the LOI of modified MH reinforced PLA has also increased compared to the unmodified MH reinforced PLA. Further, results of tensile test proofed that the organic modification could improve the compatibility of MH with the polymer, but only s...

In this paper, Plate specimens for tensile tests with two different microstructures (as-received and heat treated) were studied. Micromechanical modelling by using a representative volume element has been adopted to investigate the tensile flow behavior of Ti-6Al-4V alloy. Voronoi tessellation model and actual microstructure model were developed to predict the macroscopic stress versus strain behavior. Kinematic hardening rule was used to simulate the nonlinear hardening. Results showed that Both VT model and actual microstructure model had good ability to predict the stress-strain response. The stress and strain distribution showed that VT model agreed with the microstructure-based model well. Simulation result was consistent with experimental result that measured by digital image correlation test. In addition, the microstructure-level inhomogeneity and incompatible deformation between the hard and soft phases were the main reason for damage.

Based on a parabolic coordinate system, we theoretically design and experimentally generate hybridly polarized vector optical fields with parabolic symmetry of the first and second kinds, which can further enrich the family of vector optical fields. The wavefront of this new-kind vector optical field contains circular, elliptic and linear polarizations, and the polarizations can keep the same or change along the parabolic curves. Then we present the realization of tunable focal shift with the hybridly polarized vector optical field, and show a specific law of the focal shift of the focused hybridly polarized vector optical field with the parabolic symmetry. We hope these results can provide a new way to flexibly modulate focal fields, which can be applied in realms such as optical machining, optical trapping and information transmission.

With wide application of natural fibers in polymer composites, improvements in their flame retardancy, water absorption, and electrical resistance become an urgent need. To this end, 4.5 wt % of layered double hydroxide (LDH) is introduced into sisal fiber reinforced biobased silicone modified phenolic composites. The modified composites optimally shows 60% reduction in total heat release (20.2 MJ/m2) compared to the composites without LDH. In addition, the biobased silicone modifier TDS is incorporated into phenolic resins (SPF), to further reduce water absorption rate to 6 wt %, and increase volume electrical resistance up to 4.6 × 1016 Ω m. The SPF-SF-SDBSLDH exhibits a high impact strength of 4.2 kJ/m2, over 50% higher than the unmodified PF-SF composites. The SEM observations show that the SPF composites exhibit better interfacial interaction with sisal fiber than normal phenolic (PF) composites. All these flame retardant, impact strength and electrical resistance properties are compatible with the r...

The microstructure evolution of adiabatic shear bands (ASBs) in AISI 52100 produced under high strain rate impact loading was investigated by using scanning electron microscopy (SEM) and transmission electron microscopy (TEM). A full view of the shear band formation and development was presented. The results reveal that no strain hardening effect occurred in the AISI 52100 under the dynamic loading. Two distinct regions of the ASBs and the transition region were observed. Driven by the high shear deformation and assisted by a thermal softening effect, the formation of ASBs started in the core region under the dominant mechanism of dynamic recrystallization. It is followed by the formation of neighbouring region under the co-action of both dynamic recovery and dynamic recrystallization. Then the transition region formed which was controlled by dynamic recovery. The core region of ASBs was consisted of subgrains and fine equiaxed grains. The grains were refined either through partitioning and breaking down the elongated subgrains by entangled dislocations clusters or through splitting and rotating the elongated subgrains into small grains under a synergistic effect of shearing and twisting. The amount and size of cementites were greatly reduced in ASBs due to cementite dissolution induced by large plastic deformation and dynamic recrystallization.

In operating of a flow battery, a certain flow rate should be maintained in order to guarantee its performance. But the pump consumed power may cause significant losses for the overall battery system. In this paper, a fresh electrical model is proposed for the novel single flow zinc-nickel battery. The model consists of both battery stack part and pump power part, which consequently not only predicts accurately the battery electrical output, but also estimates the pump consumed power at different electrolyte flow rate. Based on the validated model, the influence of pump power on flow battery’s system efficiency can be evaluated at different operating modes. At last, possible means to further improve the system efficiency of battery is discussed.

Maneuvering of the fighter aerodynamic have certain requirements, this paper for needs of F-16 aircraft maneuvering, according to some existing fighter of the gas dynamic layout and parameters and establish more accurate fighter aerodynamic configuration, internal structure parameters and control input quantity. This paper also introduces the standard atmosphere model and the engine model, and analyzes the control characteristics of the aircraft by verifying the zero input response and channel coupling characteristics, and analyzes the performance of the model. This method can be applied to the performance analysis of other models.