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Hydroxyapatite (Hap) has been shown to be an excellent sorbent for F− removal of elevated levels of fluoride in groundwater worldwide; however, the molecular mechanisms of this process have not been clearly addressed. Herein, we used 19F solid-state NMR spectroscopy to investigate F− sorption mechanisms by nanosized Hap combined with 1H NMR and 1H{19F} Rotational Echo DOble Resonance (REDOR) technology in addition to other characterization methods such as Transmission Electron Microscopy (TEM), X-ray Diffraction (XRD) and Nanoscale Secondary Ion Mass Spectroscopy (NanoSIMS). Our experimental results showed that F− sorption mechanisms depend on solution pH and fluoride concentration ([F−]). At pH 7 and [F−] ≤ 50 mM, a single 19F NMR peak at −103 ppm was observed, which could be assigned to fluorapatite [Ca5(PO4)3F] (Fap) or fluoro-hydroxyapatite solid solution [Ca5(PO4)3Fx(OH)1−x; x = 0–1] (F-Hap). A simultaneous formation of fluorite (CaF2) precipitates (δF-19 = −108 ppm) was observed at higher [F−] (e.g., 100 mM), which was further confirmed by TEM and XRD analysis. The NanoSIMS and 1H{19F} REDOR analyses indicated that a dissolution-precipitation process was involved in the F− sorption on Hap. Our results strongly support the efficacy of Hap for F− removal even after several instances of regeneration, making it a cost-effective strategy for fluoride treatment.

The main goal of this paper is to perform the safety assessment of high-speed trains (HSTs) on the simply supported bridges (SSBs) under low-level earthquakes, which are frequently encountered by HSTs, utilizing spectral intensity (SI) index. First, the HST’s limit displacements, which are calculated by using the multi-body train model with detailed wheel–rail relationship, varying with train speed, frequency and amplitude of a sinusoidal base excitation are obtained. Then, based on the obtained HST’s limit displacements, the spectral intensity limits (SIL) graded by the train’s running speed are calculated, and the relationship between the bridge seismic dynamic responses and the train’s running safety was established. Next, the method that utilizes the SI and the SIL indexes to evaluate the HST’s running safety was proposed and verified by comparing with the evaluation result of the train–track–bridge interaction model. Based on the proposed SI index, the HST’s running safety on the SSBs was evaluated under earthquakes, considering different pier heights and site types. The results showed that the low-frequency components of the ground motions are unfavorable to the HST’s running safety, and the height of bridge piers has a significant impact on running safety.

In this work, a novel and practical method is developed to depict the track slab damage and residual strain evolution, where the concrete damage constitutive relation of track slabs is considered within the train–track–bridge dynamics framework. A three-step strain method is presented to judge the load/unloading, compression/tension status of track slab elements ergodically, so that the damage condition and residual strain of track slabs can be determined. To improve the computational accuracy and efficiency, the combination of the matrix augment method and iterative solution algorithm is elucidated in detail. To validate the present model, the solutions among incremental solution, iterative solution, and non-iterative solution are firstly illustrated, and then experimental studies are performed to declare the effectiveness of this model in characterising strain/stress relation of concrete no matter in compression state or in tension state, and finally, other model results are also introduced to prove the effectiveness of this model. In the numerical studies, the damage distributions of track slabs in the longitudinal and lateral direction are presented, where the influence of track irregularities and track slab positions on the bridge is clarified, besides, the evolution of the damage and residual strain of a track slab subject to a moving train is revealed.

ATR-FTIR spectroscopy was performed on a series of ZnCl2-ethylene glycol (EG) mixtures with a wide-range of compositions (1 : 1.5-1 : 14 in molar ratios), involving the stable ZnCl2-4EG deep-eutectic solvent (DES) composition, to explore the spectral variations, structural heterogeneity, and hydrogen bonding (H-bonding) properties. To enhance the resolution of the spectra, excess absorption and two-dimensional correlation spectroscopies were employed. In the initial IR spectra, a quasi-isosbestic point was identified, signaling that the major disturbance on EG microstructures by adding ZnCl2 is to form a distinct complex. Further analysis uncovered the main transformation process to be from the EG tetramer to the ZnCl2-4EG complex. It was also found that as the EG content increases, negative charge increasingly transfers to ZnCl2, resulting in the strengthening of the Zn ← O coordination bonds and the weakening and finally dissociation of Zn-Cl bonds. Regarding the ZnCl2-4EG DES, several incomparable specificities were observed. It was found that ZnCl2 destructed the H-bonding network of pure EG to the largest extent, resulting in the highest production of the dimer and trimer of EG. Moreover, in comparison with other compositions, the ZnCl2-4EG DES showed abrupt increases in the negative charge of the salt, the length of the Zn-Cl bond, and the strength of the Zn ← O coordination bond. All these imply the strongest intermolecular interactions and the highest solvation of ZnCl2 in EG at the eutectic composition compared to those of other mixtures, resulting in a super-stable liquid mixture. The work provides physical insights into the structural and interactive properties of deep-eutectic solvents.

Acoustic emission (AE) is an effective nondestructive evaluation method for assessing damage in materials; however, few works in the literature have focused on one quantification method of damage in concrete under fatigue loading by using AE for characterizing the entire three main deterioration behaviors simultaneously. These deterioration behaviors include Young’s modulus degradation, fatigue total strain, and residual strain development. In this work, an AE quantification method of fatigue damage in concrete was developed, by combining AE and a fiber bundle-based statistical damage model (fiber bundle-irreversible chain model). By establishing a relationship between normalized AE counts and the damage variable based on the fiber bundle-irreversible chain model, the method was proposed. Additionally, this method was verified against the experimental results. It is able to capture the mechanisms of damage accumulation and characterize the three deterioration behaviors simultaneously.

This paper proposes a new kind of U-type reinforcement ferrule (URF) connection for the assembly of precast concrete (PC) components, which has a good fault-tolerance ability and low cost of construction with a simple post-grouting process. The modified connection features welded U ferrules, which can increase the bonding mechanism and internal stress transmission in the spliced region. A series of quasi-static cyclic tests were performed on URF-connected PC columns with different welding patterns. Comprehensive comparisons were performed on the load-bearing capacity, the plastic energy dissipation ability, the internal force transmission, the column ductility and the stiffness. The results indicated that PC columns with welded URF connections can ensure better lateral resistance than the cast-in-place concrete column. The weld type and length influence the connection performance, and the 15d-welded and full-length welded URF connections presented better connection performance and were suggested for the assembly of PC columns. Then, finite element analyses were performed to further reveal the working and failure mechanisms and the affecting mechanism of some working parameters. Parametric simulations indicated that the increase in the axial load ratio and the concrete strength in the postcast region had a slight but limited effect on improving the lateral resistance of the column connection.

Most studies are devoted to the use of metal-organic frameworks (MOFs) as templates to construct desirable electrocatalysts in situ by high-temperature pyrolysis. The emergence of heterostructures invokes new opportunities to use the full potential of pristine MOFs as efficient catalysts in the oxygen evolution reaction (OER). Here, a MOF surface-reaction strategy is developed to synthesize MOF-based heterostructures without pyrolysis. Uniform Fe(OH)3 nanosheets are grown controllably on the Co-MOF-74 surface by a fast "phenol-Fe" reaction that takes advantage of the hydroxyl sites in Co-MOF-74. The resulting Fe(OH)3 @Co-MOF-74 heterostructure delivers an excellent performance in the OER with a low overpotential of 292 mV at 10 mA cm-2 . Notably, the introduction of Fe can improve the intrinsic activity of the original Co atom significantly. The turnover frequency in Fe(OH)3 @Co-MOF-74 (1.209 s-1 ) is more than 25 times higher than that in Co-MOF-74 (0.048 s-1 ). This work presents a fresh concept for the fundamental design of advanced pure-MOF-based heterostructures and, thereby, provides a new avenue for the fabrication of other energy-conversion and -storage materials.

In this paper, an efficient and robust approach is presented for the prediction of subway train-induced ground vibrations considering random track unevenness. The proposed approach is developed by a two-step approach. Firstly, the power spectral density functions of the wheel–rail interaction forces are obtained through the combination of the vehicle–track–tunnel–soil theoretical model and the pseudo-excitation method (PEM). Secondly, by assuming the geometry of the track, tunnel, and soil to be homogeneous along the track, the nonstationary random ground vibrations are solved by combining the PEM and the 2.5D finite element–perfectly matched layers method. To improve computational efficiency, an efficient wavenumber sampling scheme is proposed. In the numerical examples, the proposed approach is validated by comparing the results obtained with the published results. The influence of the train speed on the ground vibrations are also investigated, in which two types of track structure, namely the direct fixation track and floating slab track, are considered.

Low charge-separation transport efficiency resulting from structural defects largely limits photocatalytic hydrogen production over polymeric graphitic carbon nitride (PCN) photocatalyst. Herein, an electron-donating group, namely p-phenylene, is incorporated into PCN by a polycondensation reaction between carbon nitride and p-phenylenediamine (or p-benzoquinone) to repair the structural defects. The p-phenylene-modified PCN exhibits an almost fivefold increase in H2 evolution, a threefold increase in photocurrent density, and higher nonradiative rate (0.285 ns-1 ). Spectroscopic studies confirm that p-phenylene tends to bridge the heptazine-based oligomers through a polycondensation reaction. Theoretical calculations reveal that anchoring of the heptazine units by p-phenylene induces localization of h+ and e- on the phenylene and melem moieties, respectively, which effectively separates the charge carriers. This strategy provides an opportunity to overcome structural defects in carbon nitride for efficient photocatalytic solar energy conversion.

Transition-metal-organic frameworks (MOFs) have been regarded as one of the most intriguing electrocatalysts because of its low cost and diversity in functional organic groups and metal centers. Different from the common strategies of tuning the ratio of metal centers in multivariate MOFs, here, ultralow-content Fe2O3 is decorated on the surface of monometallic Ni-MOF-74 based on the fast "phenol-iron (Fe)" surface reaction between Fe2+ and the surface hydroxyl group in Ni-MOF-74. Benefiting from this flexible method, the Fe loading can be finely modulated and thus a series of Fe-decorated Ni-MOF-74 with different Fe contents are prepared. The optimized 0.6 wt % Fe2O3@Ni-MOF-74 with the Fe loading of 0.6 wt % only needs the overpotential of 264 mV to deliver 10 mA cm-2, which obviously outperforms Fe-free Ni-MOF-74 (323 mV) and other Fe2O3@Ni-MOF-74 and is even superior to the commercial IrO2 benchmark (300 mV). X-ray photoelectron spectroscopy results disclose that Fe decoration can obviously modulate the electronic structure of Ni center in Ni-MOF-74, thereby resulting in enhanced oxygen evolution reaction activity. This work opens up a new avenue to fabricate excellent MOF-based electrocatalysts for direct utilization in an electrocatalytic process.

Developing noble-metal-based catalysts with ultralow loading to achieve excellent performance for selective hydrogenation of alkynes under mild reaction conditions is highly desirable but still faces huge challenges. To this end, a SO3H-anchored covalent organic framework (COF-SO3H) as the support was deliberately designed, and then ultralow-content Pd (0.38 wt %) was loaded by a wet-chemistry immersion dispersion method. The resulting Pd0.38/COF-SO3H composite exhibits outstanding performance for the selective hydrogenation of phenylacetylene with 97.06% conversion and 93.15% selectivity to styrene under mild reaction conditions (1 bar of H2, 25 °C). Noticeably, the turnover frequency value reaches as high as 3888 h-1, which outperforms most of reported catalysts for such use. Moreover, such a catalyst also exhibits excellent activity for a series of other alkynes and high stability without obvious loss of catalytic performance after five consecutive cycles.

Background The prevalence of drug-resistant bacterial infections urges the development of new antibacterial agents that possess a mechanism of action different from traditional antibiotics. FtsZ has been recognized as a key functional protein in bacterial cell division and it is currently believed to be a potential target for the development of novel antibacterial agents. Purpose The primary aim of the study is to screen out an inhibitor targeting at FtsZ and followed to investigate its antibacterial activity and mode of action. Methods Cell-based cell division inhibitory screening assay, antimicrobial susceptibility test, minimum bactericidal concentration assay, time-killing curve determination, FtsZ polymerization assay, GTPase activity assay, and molecular modeling were performed in the present study. Results The screening study from a small library consisting of benzimidazole and indole derivatives discovered a compound (CZ74) with an indole-core structure. The compound exhibited strong cell division inhibitory effect. In addition, CZ74 shows high antibacterial potency against a number of tested Gram-positive bacteria, such as methicillin-resistant Staphylococcus aureus and vancomycin-resistant Enterococcus. The minimum inhibitory concentration values obtained were within the range of 2-4 µg/mL. The results of biological study revealed that CZ74 at 2 µg/mL is able to disrupt FtsZ polymerization and inhibit GTPase activity and cell division. From molecular modeling study, CZ74 is found possibly binding into the interdomain cleft of FtsZ protein and then leads to inhibitory effects. Conclusion This indole-cored molecule CZ74 could be a potential lead compound and could be further developed as a new generation of antibacterial agents targeting FtsZ to combat against multidrug-resistant bacteria.

Shaking table test is widely used as the main experimental approach to evaluate seismic performance of structures, and it usually consumes huge funds and labors. To ensure success of the tests, it is essential to evaluate the feasibility and accuracy before the test is conducted. However, research on test feasibility has rarely been reported. In recent years, complexity of shaking table tests has increased significantly due to the increasing demand of testing facility performance. Hence, feasibility evaluation becomes more and more important. In this paper, main performance indexes of the shaking table facility are expounded. According to the performance indexes of actuator parameters, a rapid feasibility evaluation method is then proposed based on the equilibrium between the facility capacity and the table output demand. Subsequently, applicability of the evaluation method is validated by evaluating the practical tests. The results show that the maximum acceleration targets in horizontal and vertical direction are mutually restrained under three-dimensional excitations. For the feasibility evaluation of large-scale model tests, the eccentric and overturning moment of specimen are the main performance control indexes due to their adverse influences on the facility. And the overturn-resistance of shaking table will be enhanced significantly by vertical actuators during the absence of vertical excitations. In the shaking table array test, millimeter-scale relative displacement between tables may lead to accidental damage of the test specimen or not working of the facility when the reinforced concrete foundation crosses the shaking tables. Therefore, attentions should be paid to the design of the test scheme.

The objective of this paper is to investigate the behaviors of concrete-filled circular stainless steel tubular (CFCSST) stub columns under axial loading. A fine finite 3D solid element model was established, and the FE results revealed that the increased ultimate bearing capacity of CFCSST stub columns compared with their carbon steel counterparts was mainly due to that the confinement effect of CFCSST stub columns was stronger than that of carbon steel counterparts and the stress contribution of stainless steel was higher than that of carbon steel. The stress nephogram was simplified reasonably in accordance with the limit state of core concrete and a formula was proposed to estimate the ultimate bearing capacity of CFCSST stub columns using superposition method. Finally, the difference of the experimental and predicted results using the proposed formula and the existing codes were illustrated.

In this study, the effect of temperature on macroperformance and microcharacteristic of carbonized concrete was investigated. The carbonation depth, compressive strength, and surface strain of concrete under different simulated environments for 28 d were measured. XRD and ESEM-EDS analysis were conducted to present the phase composition, types of hydration products, and microstructure characteristics of samples before and after carbonation. The results showed that the effects of temperature on carbonation depth, strain, and compressive strength were significant. There was a linear relation between temperature and carbonation depth as well as compressive strength of concrete. The effects of environment factors on concrete surface strain after carbonation manifested as the strain value and the slope of linear segment of strain curve. Significant differences of phase composition and hydration products were observed before and after the carbonation, which mainly manifested as attenuation and disappearance of diffraction peaks of hydration products. Temperature affects the crystal form of the carbonation products.

Through-beam connections offer the effective performance in developing the rigid connection, but the practical applications often encounter concrete pouring difficulties at the through beam region. Then an advanced through-core connection between concrete-filled steel tubular (CFST) columns and steel-concrete composite (SCC) beams is proposed in this study. The modification emphasizes the reduced beam flange width to convenient the concrete pouring, and the penetrated slab reinforcement into the CFST column to make up the strength loss from flange reduction. To investigate the seismic behavior of the connection, quasi-static cyclic loading tests on four specimens are conducted, and corresponding finite element analyses are also performed. The failure modes, hysteretic response, skeleton curve, ductility, stiffness degradation, ultimate bearing capacity, and energy dissipation of these connections are all discussed in detail. The results indicated that the proposed new connection has a favorable seismic performance. Then with FE simulations, the varying trends of the seismic behaviors, including the strain at the core area, plastic damage at core concrete and the energy dissipation proportions in the connections are all analyzed. Moreover, the influencing patterns of axial load ratio and the flange reduction degrees (RD) are also investigated through FE simulations. To ensure a good seismic performance, the maximum flange reduction degree (RD) of the steel girder is suggested to be 0.4 for the upper flanges and the ratio of the flange reduction between the lower and the upper flanges should not exceed 0.8.

The binding of metal ions with humic acid (HA) plays an important role in the aggregation of HA and the migration of metal ions in the environments. The effects of common cations (Na+, Mg2+, Ca2+ and Al3+) and heavy metal ions (Ag+, Cd2+, Cu2+, Cr3+ and Eu3+) on the aggregation of HA were investigated systematically by aggregation kinetics, spectroscopic techniques and molecular dynamic (MD) simulations. The critical coagulation concentration (CCC) of mono-, di- and trivalent cations could be predicted by the Schulze-Hardy rule. The aggregation of HA in the presence of Na+ and Ag+ was mainly due to the reduction of repulsive force and the hydrogen bonds between HA molecules. While the complexation of di- and trivalent cations with carboxylic/phenolic groups, or the cation-π interactions enhanced the intra- or inter-molecular bridges in HA and then contributed greatly to the aggregation of HA. Heavy metal ions could easily pass through the electric double-layer of HA compared with common cations. MD simulations further signified the strong aggregation ability of HA molecules in solutions containing high valence metal ions. These findings are important for understanding not only how the influence of metal ions on the aggregation of HA, but also the conditions which ions more efficient for aggregation.

This paper extends the 2D multi-time-step (MTS) method previously proposed by the authors to 3D train-track-bridge dynamic analysis for evaluating in detail the running safety and riding comfort of a train. The train-track-bridge coupled system (TTBS) is separated into the train subsystem, the track subsystem, and the bridge subsystem. These subsystems are coupled by the interaction forces between them. A fine time-step is adopted for the train subsystem and the track subsystem due to the high-frequency wheel-rail contact. A coarse time-step is adopted for the bridge subsystem due to its low-frequency vibration. To reduce the number of degrees of freedom (DOFs) of the track structure, a moving track technique is applied in this paper. The train-track-bridge coupled model with the MTS method is validated by comparing the numerical results with field measurement data of a cable-stayed bridge. A numerical simulation of a train traversing a long-span cable-stayed bridge is used to demonstrate the computational efficiency and accuracy of the proposed method. It is shown that the proposed method is accurate and computationally more efficient than using a uniform time-step for the TTBS.

In this paper, a refined three-dimensional (3D) vibration model for a train-track-girder-pier coupled system is established and solved using a pseudo-excitation method (PEM). Considering the excitation of random track irregularities, a high-speed railway case study is presented to verify the effectiveness of the model and the method by comparing the results with those given by a Monte Carlo method. A pre-stressed concrete box girder for a high-speed railway bridge with excitation of random track irregularities is used to investigate the influences of train speed and concrete Young's modulus on the random dynamic responses of the coupled system. The results show that the PEM is 1-2 orders of magnitude more computationally efficient for the random dynamic analysis of the train-track-girder-pier systems compared with the Monte Carlo method. The power spectral densities (PSDs) of vertical accelerations of coach body change only slightly with time, but they change significantly with track irregularity frequency. All the first peaks of the PSD curves for the coach body vertical acceleration are shown to appear at around the same fundamental frequency. The concrete Young's modulus of the girder has a large influence on the PSDs of the vertical acceleration of the bridge, but the distribution of vibration energy in the frequency domain varies very little. The results can be applied to railway design and maintenance.

This paper proposes a novel low-rise precast wall panel structure with bolt connections, which has advantages of convenient and rapid assembly. To investigate seismic performance of the structure system, a shaking table test of a 1/2 scaled three-story model is conducted, by which the structural dynamic responses, damage pattern, and seismic fragility are analyzed. The results show that the proposed novel precast structure system presents high stiffness, high load capacity and high collapse margin ratio. In this novel structure system, the bolt connections are critical for the structural dynamic characteristics and responses. Damage pattern of the structure follows the sequence of bolt loosening, adjoining wall panels sliding and dislocating, structural components cracking. The seismic damage of test structure is slight, and most structural components still remain elastic in maximum considered earthquakes. Based on the test results, performance design objectives for service level earthquake, design based earthquake and maximum considered earthquake are given, and four limit states are defined. The fragility curves of the structure are developed, as well as the fragility of nonstructural components.

In this work, the fatigue deterioration of the quasi-brittle materials under cyclic tension is investigated both theoretically and experimentally by considering concrete as a specific example. The deterioration relates to the total strain, residual strain and Young’s modulus are found to evolve in a three-stage process during the lifetime. A novel theoretical approach, namely, a fiber bundle-plastic chain model, is introduced to explain these behaviors. This model captures the major microscopic mechanisms of the fatigue deterioration of quasi-brittle materials, and provides a good agreement with the experimental findings.

Nuclear magnetic resonance (NMR) spectroscopy is a powerful tool in learning the structure, dynamics and interaction of biological macromolecules. In virtue of its rapid development and wide applications, NMR has become an indispensable tool in numerous research fields, which in further benefits from the improvement of NMR spectrometers based on higher sensitivity and resolution, as well as the continuous innovation of NMR experiment methods. Nowadays life science researches are not limited to the traditional questions and technologies. Multidisciplinary studies of life science, physics, chemistry and materials science become new trends. Therefore, new tools are required to study the structure and function of macromolecules in its native or mimic environments, where NMR provides a powerful and versatile weapon. Membrane protein mediates signal transduction, molecular transport and energy metabolism in cells. Hence, the therapeutic potential based on understanding the properties of membrane protein requires extensive investigation to characterize its structure and dynamics. Structural study of membrane protein presents challenging due to its low ability to form protein crystal in a mimetic membrane environment. However, NMR is a suitable tool and plays an important role in studying membrane protein, because it provides possibilities to determine the structure of membrane proteins in an environment similar to its native state. Specifically, optimal membrane mimetic including detergent micelles, bicelles and nanodiscs need to be considered in the structural study of membrane proteins, due to the size limits in solution-state NMR. On the other hand, solid-state NMR (ssNMR) has long been considered as another major method in the field of structural biology because it dominates in studying membrane proteins in native-like lipids. Moreover, oriented sample (OS) ssNMR can be applied to determine the secondary structure, orientation and topology of membrane protein in lipid bilayers, in which the sample should be uniformly aligned in the magnetic field. Recently, basing on the methodological and technological developments in the field of dynamic nuclear polarization (DNP) and proton detection, magic angle spinning (MAS) ssNMR has presented as a promising tool in completely characterization of the structure and dynamics of membrane proteins. Exploring the structure, interaction and function of biomolecules in native environment requires understanding their mechanisms thoroughly in physiologically relevant. In-cell NMR is a branch of high-resolution biomolecular NMR spectroscopy, which brings atomic-resolution insights into the states of macromolecule in native cells. To date, in-cell NMR has been successfully applied to the investigation of bacterial and eukaryotic cells, accordingly, relevant structural and functional information has been obtained. Here we give a general discourse on the existing in-cell NMR approaches and its applications in protein structure determination, interaction and stability. Bone is one of the most intricate natural materials, featuring by its highly hierarchical architecture. Nevertheless, its characteristic organic-inorganic organization presents challenging for most of conventionally analytical and biophysical techniques. Over the past several years, ssNMR has been extensively applied to materials science, enabling insights into the structure and dynamics of complicated biomaterials in atomic-scale. Particularly, ssNMR highlights its unique potential in the research of bone. Specifically, the organic matrix of bone can be explored using 13C-labeled NMR methods, while the inorganic bone mineral can be labeled by 43Ca and 31P. Furthermore, the structural arrangement of the interface between organic matrix and inorganic mineral of bone can be probed using the method of 13C {31P} rotational echo double resonance (REDOR). The abundant structural information in atomic-scale derived from ssNMR has immensely contributed to the establishment of current structural model of bone, hence, aids understanding the molecular mechanisms of bone maturation and diseases.

A fast computation method that can be used for efficient analysis of full scale three-dimensional random vibrations induced by railway traffic is presented in this paper. The method uses the pseudo-excitation method (PEM) for random analysis and the proposed multi-point synchronous algorithm (MPSA) for solution of the large sparse linear equations of the train-track-soil coupled system (TTSCS). A mixed two- and three-dimensional TTSCS model is established firstly. Based on the linear Hertzian wheel/rail contact relationship, the time-dependent equations of motion of the TTSCS are deduced. This formulation leads to a global system of equations that can be solved in a directional manner without the need for iterative processes. By means of the PEM, the self-excitation induced by the random track irregularity is transformed into a series of deterministic harmonic excitation vectors. To accelerate the computation, a fast computation strategy is proposed. In the numerical example, the proposed method is validated through comparison with field measured results. Comparison of the results of the MPSA with those of the triangular factorization algorithm and ANSYS is undertaken to evaluate the efficiency of the MPSA. It is confirmed that the MPSA can result in a five- to tenfold increase in computation efficiency.

The whole-genome sequencing (WGS) of human adenoviruses (HAdVs) plays an important role in identifying, typing, and mutation analysis of HAdVs. Nowadays, three generations of sequencing have been developed. The accuracy of first-generation sequencing is up to 99.99%, whereas this technology relies on PCR and is time consuming; the next-generation sequencing (NGS) is expensive and not cost effective for determining a few special samples; and the third-generation sequencing technology has a higher error rate. In this study, first, we developed an efficient HAdV genomic DNA extraction method. Using the complete genomic DNA instead of the PCR amplicons as the direct sequencing template and a set of walking primers, we developed the HAdV WGS method based on first-generation sequencing. The HAdV whole genomes were effectively sequenced by a set of one-way sequencing primers designed, which reduced the sequencing time and cost. More importantly, high sequence accuracy is guaranteed. Four HAdV strains (GZ01, GZ02, HK35, and HK91) were isolated from children with acute respiratory diseases (ARDs), and the complete genomes were sequenced using this method. The accurate sequences of the whole inverted terminal repeats (ITRs) at both ends of the HAdV genomes were also acquired. The genome sequence of human adenovirus type 14 (HAdV-B14) strain GZ01 acquired by this method is identical to the sequence released in GenBank, which indicates that this novel sequencing method has high accuracy. The comparative genomic analysis identified that strain GZ02 isolated in September 2010 had the identical genomic sequence with the HAdV-B14 strain GZ01 (October 2010). Therefore, strain GZ02 is the first HAdV-B14 isolate emergent in China (September 2010; GenBank acc no. MW692349). The WGS of HAdV-C2 strain HK91 and HAdV-E4 strain HK35 isolated from children with acute respiratory disease in Hong Kong were also determined by this sequencing method. In conclusion, this WGS method is fast, accurate, and universal for common human adenovirus species B, C, and E. The sequencing strategy may also be applied to the WGS of the other DNA viruses.

The objective of the current paper is to study and extend the exponential-polynomial-closure (EPC) method in analyzing the non-stationary response probabilistic solutions of nonlinear stochastic oscillators excited by combined deterministic harmonic and Gaussian white noise excitations. The probabilistic solution of the non-stationary responses of nonlinear stochastic oscillator is expressed as an exponential function of polynomial with time-variant coefficients and then the Fokker–Planck–Kolmogorov equation is solved approximately. Two validation examples are presented. The results obtained by Monte Carlo simulation (MCS) and EPC method are presented to show their good agreement, which confirms the effectiveness of the EPC method for the probabilistic solutions to nonlinear stochastic oscillators. The advantage of the EPC method for analyzing the oscillators with strong nonlinearities is investigated by comparison with Equivalent Linearization method. Furthermore, compared with MCS, the computational efficiency by using the EPC method is increased by about 56 times in the first example and 44 times in the second example.

This paper experimentally investigates the seismic behavior of tie bar stiffened round-ended concrete-filled steel tube columns. A total of 16 specimens were tested. The test parameters in...

Objective MicroRNAs (MiRNAs) is thought to play a critical role in the initiation and progress of ovarian cancer (OC). Although miRNAs has been widely recognized in ovarian cancer, the role of hsa-miR-30a-5p (miR-30a) in OC has not been fully elucidated. Methods Three mRNA datasets of normal ovarian tissue and OC, GSE18520,GSE14407 and GSE36668, were downloaded from Gene Expression Omnibus (GEO) to find the differentially expressed gene (DEG). Then the target genes of hsa-miR-30a-5p were predicted by miRWALK3.0 and TargetScan. Then, the gene overlap between DEG and the predicted target genes of miR-30a in OC was analyzed by Gene Ontology (GO) enrichment analysis. Protein-protein interaction (PPI) network was conducted by STRING and Cytoscape, and the effect of HUB gene on the outcome of OC was analyzed. Results A common pattern of up-regulation of miR-30a in OC was found. A total of 225 DEG, were identified, both OC-related and miR-30a-related. Many DEG are enriched in the interactions of intracellular matrix tissue, ion binding and biological process regulation. Among the 10 major Hub genes analyzed by PPI, five Hub genes were significantly related to the overall poor survival of OC patients, in which the low expression of ESR1,MAPK10, Tp53 and the high expression of YKT,NSF were related to poor prognosis of OC. Conclusion Our results indicate that miR-30a is of significance for the biological progress of OC.

The carbonation process of reinforced concrete (RC) beams considering the combined effect of fatigue load and environmental factors was investigated experimentally in an environmental simulation chamber based on meteorological environmental data. Fourteen beams were constructed and tested, and a carbonation numerical model (CNM) considering medium transport and fatigue damage characteristics was proposed to simulate the carbonation process of RC beams. Based on the experimental results, CNM is extended to reveal the effects of ambient temperature, relative humidity, carbon dioxide concentration, and fatigue damage on the carbonation process of RC beams. The results showed that the change in the pore structure of concrete can directly and accurately characterize the effect of fatigue damage on the transport characteristics of concrete. The porosity of concrete substantially increased with increasing levels of fatigue damage. Although fatigue damage did not have a significant effect on the most probable pore radius of the concrete, the total pore volume of the most probable pore notably increased. The results showed that both the carbonation depth and fatigue damage exhibit a three-stage development law. The depth and rate of carbonation are related to concrete pores and macroscopic cracks. In the carbonation analysis of fatigue-damaged RC beams, the changes in both the pore structure and fatigue cracks caused by repeated fatigue loading on carbonation should be considered.

The trivalent seasonal influenza vaccine was the only approved and available vaccine during the 2016–2018 influenza seasons. It did not include the B/Yamagata strain. In this study, we report an acute respiratory disease outbreak associated with influenza B/Yamagata infections in Guangzhou, Southern China (January through March, 2018). Among the 9914 patients, 2241 (22.6%) were positive for the influenza B virus, with only 312 (3.1%) positive for the influenza A virus. The influenza B/Yamagata lineage dominated during this period in Southern China. The highest incidence of influenza A virus infection occurred in the children aged 5–14 years. In contrast, populations across all age groups were susceptible to the influenza B virus. Phylogenetic, mutations, and 3D structure analyses of hemagglutinin (HA) genes were performed to assess the vaccine-virus relatedness. The recommended A/H1N1 vaccine strain (A/Michigan/45/2015) during both 2017–2018 and 2018–2019 was antigen-specific for these circulating isolates (clade 6B.1) in Spring 2018. An outbreak of influenza B/Yamagata (clade 3) infections in 2018 occurred during the absence of the corresponding vaccine during 2016–2018. The recommended influenza B/Yamagata vaccine strain (B/Phuket/3073/2013) for the following season (2018–2019) was antigen-specific. Although there were only a few influenza B/Victoria infections in Spring 2018, five amino acid mutations were identified in the HA antigenic sites of the 19 B/Victoria isolates (clade 1A), when compared with the 2016–2018 B/Victoria vaccine strain. The number was larger than expected and suggested that the influenza B HA gene may be more variable than previously thought. One of the mutations (K180N) was noted to likely alter the epitope and to potentially affect the viral antigenicity. Seven mutations were also identified in the HA antigenic sites of 2018–2020 B/Victoria vaccine strain, of which some or all may reduce immunogenicity and the protective efficacy of the vaccine, perhaps leading to more outbreaks in subsequent seasons. The combined epidemiological, phylogenetic, mutations, and 3D structural analyses of the HA genes of influenza strains reported here contribute to the understanding and evaluation of how HA mutations affect vaccine efficacy, as well as to providing important data for screening and selecting more specific, appropriate, and effective influenza vaccine candidate strains.

Objective MicroRNAs (MiRNAs) is considered to play an important role in the occurrence and development of ovarian cancer(OC). Although miRNAs has been widely recognized in ovarian cancer, the role of hsa-miR-30a-5p (miR-30a) in OC has not been fully elucidated. Methods Through the analysis of public data sets in Gene Expression Omnibus (GEO) database and literature review, the significance of miR-30a expression in OC is evaluated. Three mRNA datasets of OC and normal ovarian tissue, GSE14407, GSE18520 and GSE36668, were downloaded from GEO to find the differentially expressed gene (DEG). Then the target genes of hsa-miR-30a-5p were predicted by miRWALK3.0 and TargetScan. Then, the gene overlap between DEG and the predicted target genes of miR-30a in OC was analyzed by Gene Ontology (GO) enrichment analysis. Protein-protein interaction (PPI) network was constructed by STRING and Cytoscape, and the effect of HUB gene on the prognosis of OC was analyzed. Results A common pattern of up-regulation of miR-30a in OC was found. A total of 225 DEG, were identified, both OC-related and miR-30a-related. Many DEG are enriched in the interactions of intracellular matrix tissue, ion binding and biological process regulation. Among the 10 major Hub genes analyzed by PPI, five Hub genes were significantly related to the overall poor survival of OC patients, in which the low expression of ESR1 ,MAPK10, Tp53 and the high expression of YKT ,NSF were related to poor prognosis of OC.

The benefit of adjuvant hysterectomy after definitive concurrent chemoradiotherapy (CCRT) for locally-advanced cervical cancer (LACC) is controversial. The purpose of the present study was to systematically search the literature and perform a meta-analysis to compare overall survival (OS) and disease-free survival (DFS) between patients subjected to CCRT with hysterectomy and those who underwent CCRT alone. The PubMed, Scopus, Embase and Google scholar databases were searched. A meta-analysis to determine hazard ratios (HRs) and odds ratios (ORs) with meta-regression was performed for the following moderators: Disease stage, histology and proportion of radical hysterectomy. Data from 14 studies were included. The results indicated that patients who received CCRT with hysterectomy had significantly better OS (HR, 0.72; 95% CI, 0.56 to 0.91; I2=19%; P=0.007) and DFS (HR, 0.72; 95% CI, 0.56 to 0.93; I2=27%; P=0.01) than those treated with CCRT alone. However, in a subgroup analysis by study type, the results were significant only for retrospective studies but not for randomized controlled trials (RCTs). However, only 2 RCTs were included with small sample size, heterogeneity and low overall quality. Subgroup analyses based on the use of brachytherapy in the CCRT with hysterectomy group demonstrated no difference in OS and DFS between the two groups. Regarding the absolute numbers of death and recurrence events, no significant difference in mortality (OR, 0.91; 95% CI, 0.62 to 1.33; I2=0%; P=0.64) was determined between the two groups, but a significantly reduced incidence of recurrence was observed in the CCRT with hysterectomy group (OR, 0.61; 95% CI, 0.47-0.79; I2=29%; P=0.0002). The meta-regression results point to a significant influence of the proportion of stage II patients on OS. Despite the overall analysis indicating improved OS and DFS with the use of adjuvant hysterectomy after CCRT, subgroup analysis based on similar treatment protocols failed to demonstrate any significant benefit of hysterectomy in LACC. However, the results indicated that the recurrence rate may be higher in patients undergoing CCRT without hysterectomy. The limited quality of the studies included and selection bias from retrospective studies restrict the possibility to draw strong conclusions.

Background Acute coronary syndrome (ACS) is the leading cause of death in developing and developed countries, yet assessing the risk of its development remains challenging. Several lines of evidence indicate that small, dense low‐density lipoproteins (sd‐LDL) are associated with increased cardiovascular disease risk. We aim to evaluate sd‐LDL concentration for predicting the risk of ACS in Chinese population. Methods Baseline characteristics of 121 patients with ACS and 172 healthy controls were obtained. Plasma sd‐LDL‐C was measured using homogeneous assay, and the proportion of sd‐LDL‐C in LDL‐C was detected. Results There was gender and age effect on the sd‐LDL‐C concentration and sd‐LDL‐C/LDL‐C ratio among healthy subjects. Elevated sd‐LDL‐C concentrations and sd‐LDL‐C/LDL‐C ratio were observed in ACS patients with unstable angina pectoris (UAP), non–ST‐segment elevation myocardial infarction (STEMI), and ST‐segment elevation myocardial infarction (NSTEMI) compared with healthy controls (P

Supplemental material, Supplemental_material for A framework combining pseudo-excitation method and two-and-a-half-dimensional finite element method for random ground vibrations induced by high-speed trains by Lidong Wang, Zhihui Zhu, Pedro Alves Costa, Yu Bai, Zhiwu Yu and Yan Han in Advances in Structural Engineering