Full-Spectrum Utilization of ZIF-67/Ag NPs/NaYF4:Yb,Er Photocatalysts for Efficient Degradation of Sulfadiazine: Upconversion Mechanism and DFT Calculation.

In this work, novel ternary composite ZIF-67/Ag NPs/NaYF4:Yb,Er is synthesized by solvothermal method. The photocatalytic activity of the composite is evaluated by sulfadiazine (SDZ) degradation under simulated sunlight. High elimination efficiency of the composite is 95.4% in 180 min with good reusability and stability. The active species (h+, ·O2 - and ·OH) are identified. The attack sites and degradation process of SDZ are deeply investigated based on theoretical calculation and liquid chromatography-mass spectrometry analysis. The upconversion mechanism study shows that favorable photocatalytic effectiveness is attributed to the full utilization of sunlight through the energy transfer upconversion process and fluorescence resonance energy transfer. Additionally, the composite is endowed with outstanding light-absorbing qualities and effective photogenerated electron-hole pair separation thanks to the localized surface plasmon resonance effect of Ag nanoparticles. This work can motivate further design of novel photocatalysts with upconversion luminescence performance, which are applied to the removal of sulphonamide antibiotics in the environment.

Characterization of an ssDNA ligase and its application in aptamer circularization.

Aptamers are widely used in various biomedical areas as novel molecular recognition elements, however, short single-stranded DNA (ssDNA) or RNA oligonucleotides are easily degraded by nucleases in biological fluids. This problem can be solved by circularizing aptamers with circular ligases. Herein, a moderately thermostable ssDNA ligase was expressed and purified. The purified ligase showed good circularization activity for different length substrates and much higher circularization efficiency than T4 RNA ligase 1. Biochemical characterization revealed that the enzyme showed optimal circularization activity at pH 7.5 and 50 ᵒC. Mn2+ and Mg2+ increased enzyme circularization activity, with Mn2+ having higher activity than Mg2+. The optimal concentrations of Mn2+ and ligase were 1.25-2.5 mM and 0.02 nM, respectively. The kinetic parameters Km, Vmax and Kcat of ssDNA ligase were 1.16 µM, 10.71 µM/min, and 10.7 min-1, respectively. The ssDNA ligase efficiency was nucleotide-dependent, and 5'-G and 3'-T were the most ligase-favored terminal nucleotides. In addition, the affinity and stability of the circular aptamer were determined. The affinity constant (KD) was 4.9 µM, and the stability increased compared to its linear form. Molecular docking results showed that the circular aptamer bound to the target via two hydrogen bonds. This study provides a simple and efficient aptamer circularization modification method for improving aptamer stability and expanding its applications.

Magnetic solid-phase extraction of pyrethroid and neonicotinoid insecticides separately in environmental water samples based on alkaline or acidic group-functionalized mesoporous silica.

Pyrethroids and neonicotinoids are widely used insecticides. However, their residues have unfavorable effects on ecological systems. Magnetic solid phase extraction is a reliable pretreatment method for a better detection of insecticides at low concentrations. In this work, amino- and carboxyl-functionalized magnetic KIT-6 were designed according to the electron-accepting groups of pyrethroid molecules and electron-donating groups with neonicotinoid structures. The characterization of these two materials was conducted using transmission electron microscopy, scanning electron microscopy, nitrogen adsorption-desorption analysis, etc. The aminated composite was applied to the magnetic solid phase extraction of pyrethroid insecticides while the carboxylic one was applied to neonicotinoids, and the adsorption effects were comprehensively compared for the first time. The material dosage, solution pH, and some factors that influenced the recovery were studied and optimized. The adsorption processes of the materials were all spontaneous and exothermic. They also fitted well with pseudo-second order kinetics and Langmuir adsorption isotherms. Both physical (pore function) and chemical (electrostatic interaction) adsorption mechanisms were present in the process. The two nanocomposites were then successfully used to enrich the two kinds of insecticides in environmental water samples. The proposed method has great application potential for insecticide monitoring in complex environmental samples.

Biomass-derived porous material synthesized by one-step calcination method for the magnetic solid-phase extraction of polychlorinated biphenyls in water.

Recent findings unfold that biomass materials with the micro/mesoporous structure were often treated as adsorbents for organic substances. In this work, a one-step calcination method was adopted in the preparation of magnetic porous green bean biomass material. It has the properties of magnetism and porosity after the addition of Co(NO3 )2 and high-temperature calcination. A variety of characterizations have been operated, including energy dispersive X-ray detector, vibrating sample magnetometer, Fourier transform infrared spectroscopy, Brunauer-Emmett-Teller analysis, and so on. It has a specific surface area of 168.1611 m2 /g and a pore volume of 0.1764 cm3 /g. The material was used in magnetic solid-phase extraction of three polychlorinated biphenyls: 2-chlorobiphenyl, 4-chlorobiphenyl, and 2,2,5-trichlorobiphenyl. Several factors were investigated, such as material amount, eluents, adsorption time, solution pH, salinity, and reusability. Under optimized conditions, good recoveries (90.24-93.34%) were achieved with the relative standard deviation in a range from 2.30 to 4.83%. Three real water samples (tap, river, and lake water) were tested to verify the accuracy of the method. This method can be successfully used in the analysis of some polychlorinated biphenyls congeners in water.

[Evaluation of brain injury caused by stick type blunt instruments based on convolutional neural network and finite element method].

The finite element method is a new method to study the mechanism of brain injury caused by blunt instruments. But it is not easy to be applied because of its technology barrier of time-consuming and strong professionalism. In this study, a rapid and quantitative evaluation method was investigated to analyze the craniocerebral injury induced by blunt sticks based on convolutional neural network and finite element method. The velocity curve of stick struck and the maximum principal strain of brain tissue (cerebrum, corpus callosum, cerebellum and brainstem) from the finite element simulation were used as the input and output parameters of the convolutional neural network The convolutional neural network was trained and optimized by using the 10-fold cross-validation method. The Mean Absolute Error (MAE), Mean Square Error (MSE), and Goodness of Fit ( R 2) of the finally selected convolutional neural network model for the prediction of the maximum principal strain of the cerebrum were 0.084, 0.014, and 0.92, respectively. The predicted results of the maximum principal strain of the corpus callosum were 0.062, 0.007, 0.90, respectively. The predicted results of the maximum principal strain of the cerebellum and brainstem were 0.075, 0.011, and 0.94, respectively. These results show that the research and development of the deep convolutional neural network can quickly and accurately assess the local brain injury caused by the sticks blow, and have important application value for understanding the quantitative evaluation and the brain injury caused by the sticks struck. At the same time, this technology improves the computational efficiency and can provide a basis reference for transforming the current acceleration-based brain injury research into a focus on local brain injury research.

Strike Velocity Prediction of Stick Blunt Instruments Based on Backpropagation Neural Network.

OBJECTIVES: To analyze and predict the striking velocity range of stick blunt instruments in different populations, and to provide basic data for the biomechanical analysis of blunt force injuries in forensic identification. METHODS: Based on the Photron FASTCAM SA3 high-speed camera, Photron FASTCAM Viewer 4.0 and SPSS 26.0 software, the tester's maximum striking velocity of stick blunt instruments and related factors were calculated and analyzed, and inputed to the backpropagation (BP) neural network for training. The trained and verified BP neural network was used as the prediction model. RESULTS: A total of 180 cases were tested and 470 pieces of data were measured. The maximum striking velocity range was 11.30-35.99 m/s. Among them, there were 122 female data, the maximum striking velocity range was 11.63-29.14 m/s; there were 348 male data, the maximum striking velocity range was 20.11-35.99 m/s. The maximum striking velocity of stick blunt instruments increased with the increase of weight and height, but there was no obvious increase trend in the male group; the maximum striking velocity decreased with age, but there was no obvious downward trend in the female group. The maximum striking velocity of stick blunt instruments has no significant correlation with the material and strike posture. The root mean square error (RMSE), the mean absolute error (MAE) and the coefficient of determination (R2) of the prediction results by using BP neural network were 2.16, 1.63 and 0.92, respectively. CONCLUSIONS: The prediction model of BP neural network can meet the demand of predicting the maximum striking velocity of different populations.

Reconstruction and Quantitative Evaluation of Blunt Injury Cases by Finite Element Method.

OBJECTIVES: To reconstruct the cases of acceleration craniocerebral injury caused by blunt in forensic cases by finite element method (FEM), and to study the biomechanical mechanism and quantitative evaluation method of blunt craniocerebral injury. METHODS: Based on the established and validated finite element head model of Chinese people, the finite element model of common injury tool was established with reference to practical cases in the forensic identification, and the blunt craniocerebral injury cases were reconstructed by simulation software. The cases were evaluated quantitatively by analyzing the biomechanical parameters such as intracranial pressure, von Mises stress and the maximum principal strain of brain tissue. RESULTS: In case 1, when the left temporal parietal was hit with a round wooden stick for the first time, the maximum intracranial pressure was 359 kPa; the maximum von Mises stress of brain tissue was 3.03 kPa at the left temporal parietal; the maximum principal strain of brain tissue was 0.016 at the left temporal parietal. When the right temporal was hit with a square wooden stick for the second time, the maximum intracranial pressure was 890 kPa; the maximum von Mises stress of brain tissue was 14.79 kPa at the bottom of right temporal lobe; the maximum principal strain of brain tissue was 0.103 at the bottom of the right temporal lobe. The linear fractures occurred at the right temporal parietal skull and the right middle cranial fossa. In case 2, when the forehead and left temporal parietal were hit with a round wooden stick, the maximum intracranial pressure was 370 kPa and 1 241 kPa respectively, the maximum von Mises stress of brain tissue was 3.66 kPa and 26.73 kPa respectively at the frontal lobe and left temporal parietal lobe, and the maximum principal strain of brain tissue was 0.021 and 0.116 respectively at the frontal lobe and left temporal parietal lobe. The linear fracture occurred at the left posterior skull of the coronary suture. The damage evaluation indicators of the simulation results of the two cases exceeded their damage threshold, and the predicted craniocerebral injury sites and fractures were basically consistent with the results of the autopsy. CONCLUSIONS: The FEM can quantitatively evaluate the degree of blunt craniocerebral injury. The FEM combined with traditional method will become a powerful tool in forensic craniocerebral injury identification and will also become an effective means to realize the visualization of forensic evidence in court.

Carboxyl-functionalized biochar derived from walnut shells with enhanced aqueous adsorption of sulfonamide antibiotics.

The novel HNO3-modifitied biochar (NBC) was synthesized from walnut shell. The NBC was characterized from scanning electron microscopy, Fourier transform infrared spectroscopy, X-ray diffraction, X-ray photoelectron spectroscopy and Raman spectrum. The NBC was then used in the adsorption of sulfadiazine, sulfamethazine and sulfachloropyridazine from aqueous solution. The material surface has carbon/oxygen-contained groups, which is benefit for the adsorption. The results showed the adsorption ability of NBC on three sulfonamides were 32, 46, and 40 mg g-1, respectively. The kinetic was found to follow the Elovich model and the isotherm conformed Freundlich. Adsorption was more favorable at weak acidic solution. The interactions mainly include π-π EDA, electrostatic interaction, Lewis acid-base interaction, hydrophobic interaction and H-bond.

Magnetic solid-phase extraction of pyrethroid pesticides in environmental water samples with CoFe2 O4 -embedded porous graphitic carbon nanocomposites.

Magnetic CoFe2 O4 -embedded porous graphitic carbon nanocomposites were prepared through a facile solid-phase thermal reaction with NaCl as a template. The material was applied in the magnetic solid-phase extraction process coupled with high performance liquid chromatography with a diode array detector to detect the trace fenpropathrin, cyhalothrin, S-fenvalerate, and bifenthrin in different water samples. The synthesis conditions of nanomaterial including glucose concentration and calcination time on extraction performance for pyrethroid pesticides have been investigated. Different magnetic solid-phase extraction parameters have been studied, such as the nanomaterial amount, solution pH, eluent types, adsorption time, and the reusability. Under the optimum conditions, good recoveries (80.2-110.9%) were achieved with relative standard deviations of 0.2-5.8%. There are probably hydrophobic interactions and dipole-dipole attractions between nanocomposites and the analytes.

[Research on thorax impact injury of children at different ages based on finite element models].

The pediatric cadaver impact experiments were reconstructed using the validated finite element(FE) models of the 3-year-old and 6-year-old children. The effect of parameters, such as hammer size, material parameters and thorax anatomical structure characteristics, on the impact mechanical responses of 3-year-old and 6-year-old pediatric thorax was discussed by designing reasonable finite element simulation experiments. The research results showed that the variation of thorax contact peak force for 3-year-old group was far larger than that of 6-year-old group when the child was impacted by hammers with different size, which meant that 3-year-old child was more sensitive to hammer size. The mechanical properties of thoracic organs had little influence on the thorax injury because of the small difference between 3-year-old and 6-year-old child in this research. During the impact, rib deformation led to different impact location and deformation of internal organs because the 3-year-old and 6-year-old children had different geometrical anatomical structures, such as different size of internal organs. Therefore, the injury of internal organs in the two groups was obviously different. It is of great significance to develop children finite element models with high biofidelity according to its real anatomical structures.

Preparation of magnetic carbon/Fe3O4 supported zero-valent iron composites and their application in Pb(II) removal from aqueous solutions.

Nanoscale zero-valent iron (NZVI) was first assembled on magnetic carbon/Fe3O4 (CM) with a combination of hydrothermal and liquid phase reduction methods. The novel NZVI@CM magnetic nanocomposites have the merits of large surface area, unique magnetic property, low cost and environmental friendliness. They can be used for Pb(II) removal in aqueous solution. The materials were characterized by using transmission electron microscopy (TEM), X-ray diffraction (XRD), Fourier transform-infrared spectroscopy (FT-IR), thermogravimetric analysis (TGA), vibrating sample magnetometry (VSM), X-ray photoelectron spectroscopy (XPS) and Brunauer-Emmett-Teller (BET) adsorption. The various parameters, such as reaction time, dosage of catalyst, solution pH and acid ions concentrations were studied. The removal efficiency of Pb(II) can be obviously increased by the combination of appropriate CM and NZVI. The removal efficiency of Pb(II) is 99.7% by using 60 mg of NZVI@CM at pH 7. The kinetics study indicates that the Pb(II) removal accords to pseudo-second-order kinetics model.

[Effect of muscle biofidelity on thoracic impact biomechanical response of a six-year-old child using finite element method].

Finite element(FE) model of thorax with high biofidelity is one of the most important methods to investigate thoracic injury mechanism because of the absence of pediatric cadaver experiments. Based on the validated thorax finite element model, the FE models with equivalent muscles and real geometric muscles were developed respectively, and the effect of muscle biofidelity on thoracic injury was analyzed with reconstructing pediatric cadaver thorax impact experiments. The simulation results showed that the thoracic impact force, the maximum displacement and the maximum von-Mises stress of FE models with equivalent muscles were slightly greater than those from FE models with real geometric muscles, and the maximum principal strains of heart and lung were a little lower. And the correlation coefficient between cadaver corridor and FE model with real muscles was also greater than that between cadaver corridor and FE model with equivalent muscles. As a conclusion, the FE models with real geometric muscles can accurately reflect the biomechanical response of thorax during the impact.

[Effects of Geometrical Dimensions and Material Properties on the Rotation Characteristics of Head].

The validated finite element head model(FEHM)of a 3-year-old child,a 6-year-old child and a 50 th percentile adult were used to investigate the effects of head dimension and material parameters of brain tissues on the head rotational responses based on experimental design.Results showed that the effects of head dimension and directions of rotation on the head rotational responses were not significant under the same rotational loading condition,and the same results appeared in the viscoelastic material parameters of brain tissues.However,the head rotational responses were most sensitive to the shear modulus(G)of brain tissues relative to decay constant(ß)and bulk modulus(K).Therefore,the selection of material parameters of brain tissues is most important to the accuracy of simulation results,especially in the study of brain injury criterion under the rotational loading conditions.

Magnetic solid-phase extraction of brominated flame retardants from environmental waters with graphene-doped Fe3O4 nanocomposites.

Graphene-doped Fe3O4 nanocomposites were prepared by a solvothermal reaction of an iron source with graphene. The nanocomposites were characterized by transmission electron microscopy, atomic force microscopy, X-ray diffraction, superconducting quantum interference, Raman spectroscopy, Fourier transform infrared spectroscopy, and X-ray photoelectron spectroscopy. This nanomaterial has been used as a magnetic solid-phase extraction sorbent to extract trace brominated flame retardants from environmental waters. Various extraction parameters were optimized including dosage and reusability of the nanocomposites, and pH of sample matrix. The reliability of the magnetic solid-phase extraction protocol based on graphene-doped Fe3O4 nanocomposites was evaluated by investigating the recoveries of 2,4,6-tribromophenol, tetrabromobisphenol A, 4-bromodiphenyl ether, and 4,4'-dibromodiphenyl ether in water samples. Good recoveries (85.0-105.0%) were achieved with the relative standard deviation ranging from 1.1-7.1%. Moreover, it is speculated from characterization and magnetic solid-phase extraction experiment that there is not only π-π stacking but also possible hydrophobic interaction between the graphene-doped Fe3O4 nanocomposites and analytes.

A novel intelligent bearing fault diagnosis method based on signal process and multi-kernel joint distribution adaptation.

The present research on intelligent bearing fault diagnosis assumes that the same feature distribution is used to obtain training and testing data. However, the domain shift (distribution discrepancy) issue generally occurs in both datasets because of different operational conditions. The domain adaptation techniques are preferably applied for fault diagnosis to handle the domain shift issue. Moreover, collecting sufficient testing data or labelled data in real industries is a challenging task. Therefore, the multi-kernel joint distribution adaptation (MKJDA) with dynamic distribution alignment is proposed for bearing fault diagnosis. This method dynamically joins both the marginal and conditional distributions and uses the multi-kernel to solve the non-linear problems to extract the most effective and robust representation for cross-domain issues. Moreover, it runs with the unlabelled task domain to perform the diagnosis by iteratively updating the pseudo code. The experimental results (two public datasets and one experimental dataset) demonstrated that the proposed method (MKJDA) exhibited stable and robust accuracy while conducting bearing fault diagnosis. It can effectively address the most crucial issue: intelligent diagnosis methods must re-train the model when the distribution differs between the source domain (the model is learned) and the target domain (the learned model is applied).

Visible light and iodate/iodide mediated degradation of bisphenol A by self-assembly 3D hierarchical BiOIO3/Bi5O7I Z-scheme heterojunction: Intermediates identification, radical mechanism and DFT calculation.

Broadening the light absorption and inhibiting carrier's recombination are vital to the improvement of photocatalytic performance. Herein, self-assembly 3D hierarchical microsphere BiOIO3/Bi5O7I Z-scheme heterojunction with carrier transfer channel was firstly fabricated by in-situ solvothermal method. The degradation efficiency for bisphenol A (BPA) reached 98.9 % within 60 min visible light irradiation. The enhanced photocatalytic activity was benefited from the Z-scheme system assisted by iodate/iodide (IO3-/I-) as carrier transfer channel that not only accelerated the interfacial charge separation, but also provided massive reactive centers for obtaining high redox capacity. The vulnerable sites and the degradation pathways of BPA were identified by density functional theory calculations and liquid chromatography-mass spectrometry analyses. The toxicity of BPA and its intermediates were predicted by ECOlogical Structure Activity Relationship (ECOSAR) and the results demonstrated that BPA was eventually mineralized to harmless products. The Z-scheme charge transfer mechanism was deeply elucidated based on the role of active species (·O2-, ·OH and h+), band structure and carrier separation efficiency. This study provides a promising strategy for the photoactivity enhancement of bismuth based heterojunction in environment purification.

[Effects of head dimensions on intracranial responses based on finite element model].

A validated 5th and 95th percentile Chinese head model was used to investigate the influence of head dimensions on the biomechanical responses by comparing acceleration, intracranial pressure and shear stress of the heads with different dimensions under the same impact energy. Moreover, the reasonability of scaling method used in the research considering head dimensions was discussed by respectively scaling the small head to a big one and scaling the big head to a small one. It therefore more scientifically provides a newer and more scientific reference for the assessment of head injury.

[Development and validation of a finite element model of human knee joint for dynamic analysis].

Based on the biomechanical response of human knee joint to a front impact in occupants accidents, a finite element (FE) model of human knee joint was developed by using computer simulation technique for impacting. The model consists of human anatomical structure, including femoral condyle, tibia condyle, fibular small head, patellar, cartilage, meniscus and primary ligament. By comparing the results of the FE model with experiments of the knee joint in axial load conditions, the validation of the model was verified. Furthermore, this study provides data for the mechanical of human knee joint injury, and is helpful for the design and optimization of the vehicle protective devices.

Fabrication of ternary UiO-66(Ce)/Ag/BiOBr heterojunction for enhanced photocatalytic degradation of ketoprofen via effective electron transfer process: Pathways, DFT calculation and mechanism.

Photocatalytic oxidation technique is considered as one of the most prospective approaches to solve the problem of environmental pollution. Herein, the novel ternary nanocomposite UiO-66(Ce)/Ag/BiOBr was fabricated via simple synthetic strategy. The obtained UiO-66(Ce)/Ag/BiOBr exhibited an excellent performance and photocatalytic efficiency of ketoprofen reached 93.5% after 180 min illumination. The ·OH and ·O2- were main active species and play an important role during the photocatalytic reaction. Furthermore, intermediate products and degradation pathways of ketoprofen were analyzed based on the 3D-EEM, DFT calculation and LC-MS. The possible reaction mechanism was proposed as follows: (1) the successful construction of heterojunction broadened the light absorption range to the visible light region; (2) the design of Ce-based MOFs provided more chances for electron transfer due to the Ce4+/Ce3+ cycling; (3) the combination of plasmon resonance effect, Schottky junction and effect of Ag bridge was an important strategy to accelerate charge transfer and improve photocatalytic efficiency.

Validation of a finite element model with six-year-old child anatomical characteristics as specified in Euro NCAP Pedestrian Human Model Certification (TB024).

Accident statistics show that more than 80% of car-to-pedestrian collisions (CPC) occur when pedestrians cross the road. It is very important to establish a finite element model with natural walking posture to study the kinematics and injury mechanism of pedestrians. In this study, a finite element model of six-year-old child pedestrian is developed with detailed anatomical characteristics and posture parameters as specified in Euro NCAP Pedestrian Human Model Certification (TB024). The numerical human body model is validated in total twelve simulations in which the pedestrian is impacted against four generic vehicle models at speeds 30, 40, 50 km/h prescribed in TB024. The Head Impact Time (HIT), Contact Force and the Trajectories of HC, T12 and AC of all twelve simulations are compared with the reference corridors provided by Technical Bulletin 024. The results indicate that the numerical human body model of a six-year-old child can be used to demonstrate the suitability of the sensing system for the range of pedestrian sizes; the timing of system deployment, and the bonnet deflection due to body loading. Furthermore, the model could be a good tool for further research on pedestrian injury mechanism and the development of pedestrian protection devices.