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Sixteen secondary metabolites, including one new sesquiterpene (1, named isocyclonerodiol oxide), seven known sesquiterpenes (2–8), two sorbicillinoid polyketides (15, 16), and six known other compounds (9–14) were isolated from the fermentation broth of Trichoderma sp. T-4-1. The structure of 1 was determined by 1 D, 2 D NMR (HMBC, HSQC, 1H-1H COSY, NOESY), and HRESIMS spectra. In addition, sesquiterpenes and sorbicillinoid polyketides showed significant antiviral activities. [ABSTRACT FROM AUTHOR]

A meta‐analysis was implemented to appraise the effect of hydrocolloid dressings (HCDs) in the management of different grades of pressure wound ulcers (PWUs) in critically ill adult subjects (CIUSs). Inclusive literature research until April 2023 was done, and 969 interconnected researches were revised. The 8 picked researches, enclosed 679 critically ill adult persons at the utilized researchers' starting point; 355 of them were utilizing HCDs, and 324 were controls. Odds ratio (OR) and 95% confidence intervals (CIs) were utilized to appraise the consequences of HCDs in treating CIUSs by the dichotomous approach and a fixed or random model. HCDs had significantly higher PWU complete healing (OR, 2.15; 95% CI, 1.54–3.02, p < 0.001), PWU stage II ulcers complete healing (OR, 2.82; 95% CI, 1.40–5.69, p = 0.004), and PWU stage III ulcers complete healing (OR, 3.73; 95% CI, 1.23–11.35, p = 0.02) compared to control in critically ill adult persons. HCDs had significantly higher PWU complete healing, PWU stage II ulcers complete healing, and PWU stage III ulcers complete healing compared with control in critically ill adult persons. However, caution needs to be taken when interacting with its values since there was a low sample size of most of the chosen research found for the comparisons in the meta‐analysis. [ABSTRACT FROM AUTHOR]

Deep rock mass mechanics is a professional course which is offered to undergraduate and postgraduate students in some mining universities. This course mainly includes the following topics: the geological structure of deep rock mass, the mechanical properties of deep rocks, the strength theory of deep rock masses, stability analysis and control of deep surrounding rock classification of engineering rock masses, and the application of deep rock mechanics in underground mining engineering The purpose of this course is to present students with a basic theoretical knowledge of deep rock mass engineering. Analyzing the limitations of traditional deep rock mass mechanics teaching methods, here, we propose integrating a combined FEM/DEM (Finite Element Method/Discrete Element Method) approach into the teaching of a course on deep rock mass mechanics. The mechanical behaviors and failure instability process of rock at laboratory and engineering scales were analyzed using ELFEN software (a finite/discrete element code). The results show that a combined FEM/DEM approach as a deep rock mass mechanics teaching method is completely feasible and reasonable; this approach has the advantages of strong intuition, high reliability, time and labor savings, and low cost, which can offset the shortcomings of traditional teaching methods. Moreover, the proposed approach can stimulate students' interests in a mining course on deep rock mass mechanics, deepen students' understanding of the course curriculum, and cultivate students' innovative abilities and subjective initiatives. [ABSTRACT FROM AUTHOR]

Five metabolites (1–5), including two new sesquiterpenoids, designated ganodermanol L (1) and 4α,15-epoxyeudesmane-1β,6α,11-triol (2), together with three known structurally related compounds (3-5), have been isolated from the cultures of Streptomyces sp. XM17, a bacteria residing in the fresh feces of the giant panda Ailuropoda melanoleuca. The structures of 1–2 were established on the basis of extensive spectroscopic analyses, including 1D- and 2D-NMR (1H-1H COSY, HMQC, HMBC and NOESY) experiments. Furthermore, the absolute configuration of 1 was established by single-crystal X-ray crystallographic analyses. Of noted, these compounds were found to possessed antiviral activities using the 'pretreatment of virus' approach with IC50 values ranging from 4 to 30 nM, indicating that these sesquiterpenoids were potent in inhibiting the entry of influenza A virus. [ABSTRACT FROM AUTHOR]

Simultaneously high permeability and permittivity results in a pronounced dimensional effect in Mn-Zn ferrite cores, which makes the measured complex permeability differ for cores with different dimensions. This paper provides a succinct method to solve an inverse problem of tracing dimension-independent or intrinsic complex permeability and permittivity for Mn-Zn ferrites using two toroidal and rectangular-cross-sectioned cores with different dimensions. The apparent complex permeability of ferrite cores with other dimensions can then be predicted from the traced intrinsic values, so will the effective impedance of common-mode chokes made of such cores. The traced intrinsic permeability is in good agreement with the measured apparent complex permeability of a very small toroidal ferrite core, in which dimensional effect can be ignored. The apparent complex permeabilities of ferrite cores with other dimensions are measured experimentally, and are also calculated from the determined intrinsic values. A very good agreement between the measured and calculated values is found. Index Terms--Complex permeability, complex permittivity, dimensional effect, Mn-Zn ferrite, Newton-Raphson method.

In the coaxial transmission line method, a factor that greatly influences the accuracy of the results is the air gaps between the material under test and the coaxial transmission line test fixture. In this paper, we discuss the influence of the air gaps and the measures that can be taken to minimize that influence when Mn-Zn ferrites are measured. We propose an improved simulation model of the coaxial transmission line test fixture holding the material under test in which the air gaps are filled with conductive materials. By combining the improved simulation model, the mode-matching method, and the Newton-Raphson method, the Mn-Zn ferrites' intrinsic complex permeability and permittivity can be determined accurately, even if the conductor-filled gaps are quite wide. We also examine the influence of the finite conductivity of the coaxial transmission line test fixture. We manufactured a coaxial transmission line test fixture to measure the intrinsic complex permeability and permittivity of Mn-Zn ferrites in the frequency range from 10 to 200 MHz. The intrinsic values thus determined have been experimentally verified. We describe the structure of the test fixture, its calibration issues, and the experimental results. Index Terms--Coaxial transmission line method, Mn-Zn ferrites, permeability, permittivity.

By combining the main features of the 2-D finite-difference time domain (FDTD) method and the traditional finite-difference frequency domain (FDFD) method, a 2-D FDFD method with nonuniform grids and perfectly matched layers (PML) is presented in this paper to analyze axially symmetrical coaxial discontinuity structures. Numerical results show that the 2-D FDFD method is much more efficient than the commonly used 2-D FDTD method in solving the frequency response of the structures. High accuracy of the 2-D FDFD method is shown in a simple numerical example which can be solved by using the mode matching method. Index Terms--Coaxial discontinuity structure, finite-difference frequency domain (FDFD) method, finite-difference time domain (FDTD) method, mode matching method, S parameters.

Limitations of the published lumped circuit methods for determination of the Mn--Zn ferrites' intrinsic complex permeability and permittivity are revealed by careful theoretical examination of their models used to calculate the impedances of the ferrite core inductor and the ferrite core capacitor. To eliminate those limitations, a method without dimensional assumptions on the measurement sample is presented. Theoretical and experimental comparison of the new method and the published methods shows that the new method has higher accuracy while maintaining high computational efficiency. Index Terms--Complex permeability, complex permittivity, lumped circuit method, Mn--Zn ferrite.

To identify the location of partial discharge occurring in a power cable, it is essential to obtain the intrinsic values of permittivity of cross-linked polyethylene (XLPE) material. This paper reveals that when the conventional two-parallel-electrode method is used, and due to the fringing effect, the measured permittivity of XLPE material pronouncedly differs from its intrinsic value, consequently significant measurement error could occur. An effective method based on the field-circuit coupled theory is presented in this paper to investigate the difference between the measured and intrinsic permittivity of XLPE insulation material. A capacitor constructed from a concentrically cylindrical XLPE sample is used. By assuming a certain value of the intrinsic permittivity for XLPE material, the electric field distribution in the XLPE material and the ambient is calculated. Then the total energy is determined, as well as the measurable permittivity. By assuming different values of intrinsic permittivity, corresponding measurable values of permittivity are determined, and a curve of measurable permittivity against its intrinsic value is then obtained, from which the intrinsic value can be found once its measurable value is obtained from experiment. The influence factors of the correction curve are analyzed, i.e. the sizes of sample and electrode. A measurement was carried out to verify this method. Index Terms--Permittivity, XLPE, complex power, field-circuit coupled method.

Analysis of the principle of the published lumped circuit methods for determination of the intrinsic complex permeability and permittivity of the Mn--Zn ferrites reveals that as long as the electric and the magnetic field distributions in the core(s) in two measurements are different, the two intrinsic values can be determined. Using this principle, we developed a set of general lumped circuit methods based on a toroidal Mn-Zn ferrite core as the measurement sample. We examined two possible different excitation modes: magnetic field excitation and electric field excitation. The two different excitation modes result in significantly different field distributions in the sample. Thus, high accuracy can be guaranteed in principle. For the magnetic field excitation, we present in this paper a general finite-difference method to solve the fields in the core and the impedance of the ferrite core inductor. To avoid the stray capacitance among the coils of the ferrite core winding inductor in the measurement, we made a set of short-ended coaxial test fixtures. We performed experiments to determine the intrinsic complex permeability and permittivity of a Mn--Zn ferrite core up to 10 MHz by using the two general methods and validated the measured intrinsic values experimentally. Index Terms--Finite-difference method, Mn--Zn ferrites, permeability, permittivity.

After setting up a mathematical model for rectangular-shaped Mn-Zn ferrite capacitors, this paper investigates dimensional effects on the intrinsic complex permittivity and the measured apparent complex permittivity of Mn-Zn ferrite blocks. The simple block structure of the samples guarantees their easy and precise preparation. Above a few hundred kilohertz, dimensional effects make the measured apparent complex permittivity deviate from its intrinsic value. This paper uses a Newton-Raphson based method to trace the intrinsic complex permittivity and permeability from the measured impedances of two rectangular-shaped Mn-Zn ferrite capacitors in the frequency range from a few hundred kilohertz to 40 MHz. From the traced intrinsic complex permittivity and permeability, the apparent complex permittivity of a third sample with different dimensions is then calculated theoretically. The papers also presents results of experiments carried out to measure the apparent complex permittivity of the third sample; agreement between the measured and the calculated values is very good. This justifies the validity of the method presented in this paper, when used to determine the dimension-independent intrinsic complex permittivity and permeability of Mn-Zn ferrites. Index Terms--Apparent complex permittivity, complex permeability, dimensional effects, Mn-Zn ferrite, Newton-Raphson method.

This paper presents a fast and efficient algorithm, based on the finite-difference method, to extract intrinsic complex permeability and permittivity from measured values for Mn-Zn ferrite cores. Our algorithm is considerably more efficient than the analytical solution-based Newton-Raphson method and reduces computing time from hours to tens of seconds. Index Terms--Finite-difference method, Mn-Zn ferrites, Newton-Raphson method, permeability, permittivity.

Research on underground coal mines has primarily focused on the stability of roadways. Mining activities lead to significant damage to the surrounding rocks and also degrade the support to the roadways. Considering the 21309 roadway of the Huojitu coal mine as a case study, this work comprehensively analyzed the characteristics of the surrounding rock using three methods: theoretical calculations, FLAC3D numerical modeling, and field observations. The results indicate that, under the influence of secondary mining, the failure range and stress concentration degree of the surrounding rock are considerably higher than those under the influence of primary mining. In this case, the maximum damage range in the surrounding rock can reach 1.8 m, the maximum principal stress can reach 19.82 MPa, and the ratio of the maximum principal stress to the minimum principal stress can reach 1.95. According to the results, the previous support design for roadways was optimized and applied in the field. Field monitoring revealed that the roadway deformation was effectively controlled, and the optimized support design was safe and reliable. This study is expected to serve as a reference for support designs or optimization under similar geological conditions. [ABSTRACT FROM AUTHOR]

Studies regarding the reuse of a gob‐side roadway formed by the N00 longwall mining method are scarce. To investigate the mine pressure behavior characteristics during roadway reuse, the anchor cable force, roof‐to‐floor deformation, and working resistance of the hydraulic support obtained from the verification working face were analyzed. Test results show that the influence range of the mining‐induced pressure was 0‐90 m in front of the working face. The ratios of the first and periodic weighting steps between the entry‐retaining and non‐roof‐cutting sides were 20.25 and 1.94, respectively. However, the ratios of the ground pressure strengths at the two sides were 1.07 and 1.31, respectively. The results indicate that the monitored roadway can be classified into three deformation zones based on the severity of the mine pressure behavior: large, intermediate, and creep. The main roof between the adjacent working faces exhibited a failure type comprising the "O‐X" and "O‐Y" states, which resulted in an unconventional mine pressure behavior. This study provides insights into the N00 longwall mining method as well as important guidance for tackling similar geological conditions when using this mining method. [ABSTRACT FROM AUTHOR]

The controlling effect of vertical stress of mountainous region on gas occurrence of the coal seam below it has always been ignored. In order to clearly express its influence mechanism, the change laws of depth, stress, and permeability of coal seam pressurised by the overlying mountain were studied based on the Winkler elastic foundation beam theory and seepage theory in the paper. At the same time, the enrichment mechanism of the coal seam pressurised by the overlying mountain was analyzed. The results showed the following: (1) There was a significantly strong correlation between the stress, permeability change rule of the coal seam, burial depth, and surface elevation under such condition. (2) Under the action of the vertical pressure of the mountain, the stress and permeability distribution of the coal seam showed significant nonlinear characteristics. The stress was the greatest under the peak, and the permeability was the smallest. (3) The initial gas content value was controlled by the permeability and the stress of the coal seam in the situation. Moreover, the field practice showed that under the action of vertical pressure of the mountain, the evaluation law of gas content was coupling with the surface elevation of the overlying mountain. In addition, the gas emission change law during the excavation of the driving face also showed the same characteristics. The results might be of great significance for the development and utilization of coal-bed gas and the safe exploitation of coal resources. [ABSTRACT FROM AUTHOR]

As the mining depth increases, under the influence of high ground stress, the surrounding rock of deep mine roadways shows soft rock characteristics. Under the influence of mining disturbance at the working face, large deformation of the roadway has occurred. To control the large deformation of the roadway, many mines have adopted the form of combined support, which has continuously increased the support strength and achieved a certain effect. However, since the stress environment of the surrounding rock of the roadway has not been changed, large deformation of the roadway still occurs in many cases. Based on the theoretical basis of academician Manchao He's "short cantilever beam by roof cutting," this paper puts forward the plan of "presplitting blasting + combined support" to control the large deformation of the deep mine roadways. Without changing the original support conditions of the roadway, presplitting blasting the roof strata of the roadway, by cutting off the mechanical connection of the roof strata between the roadway and gob, improves the stress distribution of the roadway to control the large deformation. Through field tests, the results show that after presplitting blasting the roadway roof, the roadway roof subsidence is reduced by 47.9%, the ribs displacement is reduced by 45.7%, and the floor heave volume is reduced by 50.8%. The effect is significant. [ABSTRACT FROM AUTHOR]

Nonpillar mining (NPM) with an automatically formed roadway is an emerging mining technology that does not use coal pillar retention and drivage. This technology can be used to actively control the caving height of the roof by directional cutting technology and can promote the rapid equilibrium of a fractured high roof under the support of the caved gangue. Therefore, when analyzing the stability of a high roof under NPM, not only the interaction force of the fractured rock blocks but also the effects of the support provided by the gangue, and the coal body should be considered. In addition, if necessary, the roof support in the roadway should also be considered. Based on this idea, in this paper, we analyzed the stability characteristics of a fractured high roof and suggested the stability conditions of the fractured rock of a high roof, including actual stability, pseudostability, and instability and provided the criteria for determining these three stability conditions. Furthermore, a visualized approach for the determination of roof stability was proposed. The core idea of the proposed approach is to transform the parameters that cannot be measured in the abovementioned conditions into visualized data that can be directly or indirectly obtained in the field, allowing for the detection and occasional assessment of the stability condition of the fractured rock of a high roof. This visualized determination approach can be used to assess the roof stability condition in a timely manner during the production process and to ensure production safety. The abovementioned research results were successfully used in the S1201‐II mining face of the Ningtiaota Coal Mine, indicating that the proposed approach is feasible and can be used under similar conditions. [ABSTRACT FROM AUTHOR]

The key block of the basic roof is the main contributor to the structural stability of a roadway. Research on the stability of the key block structure is of great significance for the promotion of noncoal pillar mining with automatically formed gob-side entry (GEFANM) technology. This paper is set in the engineering context of the GEFANM experiment at the Ningtiaota Coal Mine. The study fully considered the differences in the gob roof caving on the roof-cutting-line side, and the range of rotation angles to maintain a stable key block was determined. Based on this range of rotation angles, the range of safe bulking coefficients of gangue was calculated. The bulking coefficient of the gangue on the gravel side of the roadway was used as the metric in a new monitoring method and in the calculation of the field parameters. The range of safe bulking coefficients was determined to be 1.40–1.37. Field monitoring was conducted to obtain the gangue bulking coefficient on the gravel side. Combining the roof and floor convergence data, when the bulking coefficient fell within the safe range, the convergence was 95–113 mm. In this stage, the key block structure was stable. When the gangue bulking coefficient fell outside the safe range, the convergence was larger, and cracks were observed. The key block may be vulnerable to instability. The results affirmed that the gangue bulking coefficient can be used as a monitoring metric to study the stability of key block structures. [ABSTRACT FROM AUTHOR]

This paper analyzed the bandwidth limit of a class of ultrathin metamaterial screens for reducing reflectivity. The screens consist of arrays of conducting strips or square patches on top of a planar lossy dielectric or magnetic substrate backed by a conducting ground plane. An accurate analytical model has been derived to calculate the reflection coefficients of the screens, which take into account accurately the high order modes between the array and the ground plane. Based on the analytical model, the maximum bandwidth of the screens was explained. The factors determining the maximum bandwidth of the screens were revealed, which can serve as guidelines for the design of the ultrathin metamaterial screens. [ABSTRACT FROM AUTHOR]

To solve the problems in blasting roof-cutting related to pressure-relief entry retaining mining, a liquid directional roof-cutting technology is proposed in this article. To verify the adaptability of liquid directional roof-cutting technology in the practice of pressure-relief entry retaining mining, a lab cutting test was performed. The effects of the four main cutting parameters (type of abrasive, pump station pressure, speed of cutting head, nozzle diameter) on cutting capacity were examined through the test, and the optimal cutting parameters thatmeet the design requirements were ultimately identified. Based on the above test parameters, field engineering test equipment was developed. The results of a hole mouth cutting test and single-hole unilateral cutting test show that the liquid directional roof-cutting technology can be used to complete field cutting work, and the cutting depth and directional function can meet the design requirements. However, some new problems were found in the field application. For example, in the process of multihole bilateral cutting, the rock mass between four holes cannot form a cut-through face. However, these problems can be addressed by increasing the cutting capacity and optimizing the seamdirection. In summary, the design idea of conducting roof directional cutting by using liquid directional cutting technology is viable, and the proposed technology is expected to replace blasting work in several engineering applications requiring pressure relief, such as impact pressure control and coal and gas outburst control. [ABSTRACT FROM AUTHOR]

The effective control of large roadway deformations has always been a focus and difficulty in the coal industry. At present, a "bolt + cable + mesh + shotcrete" combined support structure has been widely used in China to support roadways with large deformations, and this method has achieved some success. However, large roadway deformations supported by using the "bolt + cable + mesh + shotcrete" support structure still have a series of engineering problems. This paper describes a case study of large deformation control in a roadway surrounded with broken rock located in the Du'erping coal mine in the Shanxi Province of China. A new "shell + bolt + shotcrete" combined support structure is proposed to support the north wing main haulage roadway. Methods were adopted from theoretical analysis, numerical simulation, and similarity simulation experiments to design a reinforced shell within a vertical wall semicircular arch. Roadway convergence and surrounding rock stress were monitored on the site. The monitoring data showed that the new support structure successfully controlled a potentially large deformation of the roadway. This new combined support structure provides a helpful reference for the design and engineering of support structures to prevent large roadway deformations. [ABSTRACT FROM AUTHOR]

Stress concentration caused by tectonic stress and mining disturbance in coal mines induces a unique type of rock burst. No. 3201 working face controlled by an anticline structure in the Shandong mining area is used as the research background. The formation mechanism for anticlines is analyzed. Theoretical research shows that the bigger the tectonic couple is, the smaller the foundation stiffness, and the greater the bending degree and elastic strain energy of the coal will be. The distribution characteristics of abutment pressure and maximum principle stress in anticlinal control areas are analyzed using UDEC numerical software. The results show that rock bursts result from interactions between abutment pressure and residual tectonic stress. The “connection-overlay-separation” phenomenon of abutment pressure presents with working face advancement. Furthermore, the energy criterion for rock burst initiation is established based on the energy principle. Residual energy “E0−EC” and rock burst danger characteristics during mining are discussed. Based on the simulation results, microseismic monitoring data for No. 3201 working face are analyzed, and the law of microseismic energy is consistent with the variation law for the residual energy “E0−EC” at the peak of the simulated abutment pressure. The microseismic energy and frequency are higher during mining, increasing the risk of rock burst events. It can provide scientific basis for prevention and control of rock burst. [ABSTRACT FROM AUTHOR]

In this paper, we report the fabrication of a homogeneous anisotropic invisibility carpet cloak that works for transverse magnetic (TM) wave in free space. Linear coordinate transformation is employed for the design of the dielectric tensors, and the cloak is made of Al2O3 slabs with a Teflon background. The triangular invisible region has a height of 32.4 mm (one third of the height of the whole device) and a width of 200 mm. The cloaking effect is examined in far-field free-space transmission experiments by measuring the scattering parameters. The results show our device has very good cloaking performance in a wide frequency range from 8 to 12 GHz. [ABSTRACT FROM AUTHOR]

This paper presents a class of ultrathin metamaterial screens for microwave reflectivity reduction from metallic surfaces. The screens consist of a highly conductive sheet with periodic patterns on top of a thin grounded lossy substrate. The periodic patterns of the screens are composed of nonuniform patches. It is found that the considered screens exhibit about 60% larger working bandwidth than those with uniform patches. A simple analytical equivalent circuit is also derived for mechanism understanding and quick design for the screens. [ABSTRACT FROM AUTHOR]

This paper presents an ultrathin screen with magnetic substrate for broadband microwave reflectivity reduction. The magnetic substrate was fabricated by mixing a MnTi substituted M-type barium ferrite and a Co substituted W-type barium ferrite. The screen with the magnetic substrate thickness of 1.1 mm (λ0/25) can achieve the fractional bandwidth (Δf/f0) of 46% at X band, which almost increases by 150%, as compared to the corresponding screen with dielectric substrate. [ABSTRACT FROM AUTHOR]

A new aliphatic acid, compound 1, together with six known metabolites, including nonactic acid (2), homononactic acid (3), ethyl homononactate (4), homononactylhomononactate (5), valinomycin (6), and cyclo-(Pro-Leu) (7), was isolated from the culture broth of Streptomyces sp. BM-8, an actinobacterial strain isolated from the feces of Equus quagga. The structures of these compounds were established by analyses of spectroscopic data, including 1D and 2D nuclear magnetic resonance spectra (NMR), as well as by HR-ESI-MS spectrometry and chemical derivative analyses. Additionally, a serial analogue of nonactic acid and homononacticacid (8–21) was synthesized. The cytotoxicity of 1–21 wastested against a panel of cancer cell lines, such as HT-29, MCF-7, A375 and K562, with MTT assay. In addition, the cytotoxicity tests revealed that 1 was less cytotoxic toward a panel of cancerous cells, as compared with valinomycin (6). [ABSTRACT FROM AUTHOR]

In order to reduce large deformation failure occurrences in non-pillar longwall mining entries due to roof weighting behaviors, a case study in Halagou coal mine was conducted on optimization and control techniques for entry stability in non-pillar longwall mining. The Universal Discrete Element Code (UDEC) modeling was adopted to study entry stability in non-pillar mining, and the characteristics of deformation and stress and crack propagation were revealed. The large deformation transmission between the entry-immediate roof and the gob-immediate roof could be eliminated by optimizing the entry roof structure through a directional roof-cutting method. The localized tensile stresses generated in the entry-surrounding rock caused the generation of coalescent macroscopic fractures, which resulted in the instability of the entry. The tensile stress state could be inhibited by an active flexible support system through enhancing the confining pressure on the surrounding rock. Serious rotation subsidence occurs in the entry roof due to periodic weighting of the main roof, which could be greatly reduced by a passive rigid support pattern. The numerical and field test results both showed that the roof weighting pressure was offloaded by the technique and that the deformation of the entry surrounding the rock in non-pillar mining was quite small. Thus, the technique can effectively ensure the stability of the gob-side entry, which can provide references for entry stability control in non-pillar longwall mining. [ABSTRACT FROM AUTHOR]

[Display omitted] Influenza A virus (IAV) is one of the leading causes of respiratory illness and continues to cause pandemics around the world. Against this backdrop, drug resistance poses a challenge to existing antiviral drugs, and hence, there is an urgent need for developing new antiviral drugs. In this study, we obtained a phenolic compound SG -7, a derivative of natural compound 2-hydroxymethyl-1,4-hydroquinone, which exhibits inhibitory activity toward a panel of influenza viruses and has low cellular toxicity. Mechanistic studies have shown that SG -7 exerts its anti-IAV properties by acting on the virus itself and modulating host signaling pathways. Namely, SG -7 targets the HA2 subunit of hemagglutinin (HA) to block the fusion of viral-cellular membranes and inhibits IAV-induced oxidative stress and overexpression of pro-inflammatory factors by activating the Nrf2/HO-1 pathway and reducing NF-κB activation. In addition, SG -7 can enhance type I IFN antiviral response by inducing Nrf2 expression. Importantly, SG-7 showed the ability to inhibit viral replication in the lungs of IAV-infected mice and reduce their mortality. Therefore, SG-7 may be a promising lead compound for anti-influenza drug development. [ABSTRACT FROM AUTHOR]

Objective: The purpose of this study is to analyze the inherent relationship between the score values and the biomechanical characteristics of the forward kicking motion, we aim to identify the fundamental variables influencing the score values of the forward kicking motion and establish the key biomechanical factors that effectively trigger scoring in the forward kicking motion. Methods: The DaeDo electronic scoring system was used with the Vicon optical motion capture system and the Kistler 3D force platform to obtain kinematic and kinetic variables of the front roundhouse kick motion. Linear bivariate correlation analysis and principal component analysis were used to analyze the associations between kinematic, kinetic variables, and scoring values, and summarize key biomechanical factors for effectively scoring. Results: The peak ankle plantar flexion angle and knee extension torque of the kicking leg showed a significant negative correlation with scoring values ( r < 0, p < 0.05), while other variables showed no statistical significance. The peak knee flexion angle and hip extension angular velocity of the supporting leg showed a significant positive correlation with scoring values ( r > 0, p < 0.01), while the peak ankle plantar flexion torque showed a significant negative correlation with scoring values ( r < 0, p < 0.05), and other variables showed no statistically significant correlation. The absolute values of eigenvectors of the first and second principal components, which included hip angular velocity, ankle angle, knee torque, and hip torque, were relatively large, indicating their strong influence on effective scoring triggering. Conclusion: Maintaining ankle dorsiflexion and a larger knee flexion angle in the kicking leg is favorable for triggering scoring. Higher knee flexion angle and hip extension angular velocity in the supporting leg are also advantageous for triggering scoring. "Body posture" and "Strength" are key factors that effectively trigger scoring., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2024 Jia, Ma, Huang, Liu, Wang, Lin, Peng, Xiong and Zheng.)

The indoor air quality has a direct impact on human health. In order to obtain the current status of indoor air quality in typical sports buildings in hot summer and cold winter climate zones in China, indoor badminton courts in 10 cities in Hubei Province in this climate zone were selected as research objects for field testing of indoor environmental parameters in spring and autumn, and predict air quality parameters for non-testing times. All the tested stadiums are naturally ventilated in non-event conditions, and the average daily indoor CO 2 concentration was 526.78 ppm in spring and 527.63 ppm in autumn, and the average daily PM 2.5 concentration was 0.035 mg/m 3 in spring and 0.024 mg/m 3 in autumn, all of which met the requirements of GB/T 18883-2022, the average concentration of CO 2  ≤ 1000 ppm and PM 2.5  ≤ 0.05 mg/m 3 . The indoor CO 2 concentration and PM 2.5 concentration of the tested badminton halls under natural ventilation gradually increased with the accumulation of exercise time, making the indoor air quality of the badminton halls decrease, which would negatively affect the health of the people exercising in this environment., (© 2024. The Author(s).)

Objective: To explore the inherent relationship between lower limb biomechanical indicators and effective scoring values of double roundhouse kick (DRK) by taekwondo athletes, and to find key biomechanical factors that trigger effective scoring. Methods: Using the DAEDO Protector and Scoring System (PSS) in conjunction with the Vicon optical motion capture system and Kistler 3D force plate, kinematic and dynamic indicators of the front kicking motion were obtained from 12 professional taekwondo athletes (18.00 ± 2.20 years, 182.15 ± 8.62 cm and 70.00 ± 14.82 kg). The correlation between kinematics, dynamics, and scoring values was initially analyzed using bivariate linear correlation. Subsequently, based on the results of the linear correlation analysis, a stepwise regression analysis was performed to establish a stepwise regression equation. Results: The results reveal that during the First Hit, there is a significant positive correlation (r > 0, p < 0.05) between peak hip flexion angular velocity of the dominant leg, knee abduction angle, and peak foot horizontal plane linear velocity of the non-dominant leg with effective score. On the other hand, peak ankle flexion angular velocity of the non-dominant leg, peak foot sagittal plane linear velocity, peak hip abduction angle, and peak hip flexion angle of the dominant leg exhibit a significant negative correlation (r < 0, p < 0.05) with effective score. These correlations hold statistical significance (DW> 1.023). During the Second Hit, there is a significant positive correlation (r > 0, p < 0.05) between peak ankle internal rotation angular velocity of the dominant leg, foot coronal plane linear velocity, hip adduction angular velocity, and peak ankle internal rotation moment of the non-dominant leg with effective score. Conversely, peak hip flexion angle of the dominant leg shows a significant negative correlation (r < 0, p < 0.05) with effective score. All these variables have a statistically significant impact on effective score (DW > 1.023). Conclusion: Explosive power, body posture, adequate terminal velocity, and body rotation have an association with effective scoring of the electronic protector. The peak angular velocity of the ankle joint of the dominant leg and the peak linear velocity of the foot horizontal plane of the non-dominant leg significantly contribute to the effectiveness score of the electronic protector., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2024 Jia, Liu, Huang, Ma, Lin, Peng, Xiong, Wang and Zheng.)

Background: Dental caries is an oral disease associated with infection by microbial biofilm. The metabolic activity of cariogenic bacteria results in a pH decrease in the plaque biofilm, causing tooth demineralization. This acidic environment favors the growth of cariogenic bacteria that are highly resistant to strong acids, which, in turn, produce more acid resulting in a further decrease in the pH of the plaque biofilm. Therefore, the strategy of utilizing the acidic dental plaque microenvironment to prevent and treat dental caries has become a hot research topic in recent years, such as the development of pH-sensitive drug delivery systems., Aims: Design of a new acid-activated antibacterial peptide., Objectives: To design and synthesis an acid targeted antimicrobial peptide with the GWHHFFHFFHFF sequence., Methods: Minimum inhibitory concentration (MIC) and minimum bacterial concentration (MBC) testing confirmed its antibacterial activity. Propidium iodide (PI) staining was used to detect nucleic acid leakage. Determination of anti-biofilm activity by biofilm inhibition assay. A phototoxicity study confirmed the phototoxicity of PPIX-P12., Results: MIC and MBC testing confirmed that P12 possessed acid-activated anti- Streptococcus mutans activity. Bactericidal kinetic experiments and propidium iodide (PI) staining experiments showed that P12 killed planktonic S. mutans UA159 cells leading to the leakage of nucleic acids in the acidic medium. Moreover, P12 showed acid-activated anti-biofilms at the early and mature biofilm stages. P12 was conjugated with the phototherapeutic agent protoporphyrin IX (PpIX) to construct the protoporphyrin derivative PpIX-P12. In vitro experiments revealed that PpIX-P12 displayed better antibacterial activity in pH 5.5 medium than in pH 7.2 medium., Conclusion: In conclusion, we designed an acid-activated AMP, which had no antimicrobial activity at neutral pH, but had antimicrobial activity at an acidic pH., (Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.net.)

IQSEC2 (aka BRAG1) is a guanine nucleotide exchange factor (GEF) highly enriched in synapses. As a top neurodevelopmental disorder risk gene, numerous mutations are identified in Iqsec2 in patients with intellectual disabilities accompanied by other developmental, neurological, and psychiatric symptoms, though with poorly understood underlying molecular mechanisms. The atomic structures of IQSECs, together with biochemical analysis, presented in this study reveal an autoinhibition and Ca2+-dependent allosteric activation mechanism for all IQSECs and rationalize how each identified Iqsec2 mutation can alter the structure and function of the enzyme. Transgenic mice modeling two pathogenic variants of Iqsec2 (R359C and Q801P), with one activating and the other inhibiting the GEF activity of the enzyme, recapitulate distinct clinical phenotypes in patients. Our study demonstrates that different mutations on one gene such as Iqsec2 can have distinct neurological phenotypes and accordingly will require different therapeutic strategies., (© 2023 Bai et al.)

We placed active magnetic metamaterials on metallic surface to implement a tunable reflector with excellent agile performance. By incorporating active elements into the unit cells of the magnetic metamaterial, this active magnetic metamaterial can be tuned to switch function of the reflector among a perfect absorber, a perfect reflector and a gain reflector. This brings about DC control lines to electrically tune the active magnetic metamaterial with positive loss, zero loss and even negative loss. The design, analytical and numerical simulation methods, and experimental results of the tunable reflector are presented.

In this paper, we report a fabrication of a three-dimensional (3D) carpet cloak that works for any polarization in free space. Two-dimensional (2D) conformal mapping is first employed and the 3D structure is generated by a rotation of the 2D cloak. The structure of the cloak is hole-in-dielectric. The triangular invisible region has a height of 36 mm (one third of the height of the whole device) and a width of 240 mm. The cloaking effect is examined in free space by measuring the scattering parameters. The results show our device has very good cloaking performance in a wide frequency range from 4 to 10 GHz.