Search

Summary: Dysregulated macrophage polarization from pro-inflammatory M1 to anti-inflammatory M2 phenotypes underlies impaired cutaneous wound healing. This study reveals Vγ4+ γδ T cells spatiotemporally calibrate macrophage trajectories during skin repair via sophisticated interferon-γ (IFN-γ) conditioning across multiple interconnected tissues. Locally within wound beds, infiltrating Vγ4+ γδ T cells directly potentiate M1 activation and suppress M2 polarization thereby prolonging local inflammation. In draining lymph nodes, infiltrated Vγ4+ γδ T cells expand populations of IFN-γ-competent lymphocytes which disseminate systemically and infiltrate into wound tissues, further enforcing M1 macrophages programming. Moreover, Vγ4+γδ T cells flushed into bone marrow stimulate increased IFN-γ production, which elevates the output of pro-inflammatory Ly6C+monocytes. Mobilization of these monocytes continually replenishes the M1 macrophage pool in wounds, preventing phenotypic conversion to M2 activation. Thus, multi-axis coordination of macrophage activation trajectories by trafficking Vγ4+ γδ T cells provides a sophisticated immunological mechanism regulating inflammation timing and resolution during skin repair.

Modern solid wood armchairs are developing in the direction of simplicity and lightness, and favored by the market. However, the low mechanical strength of the connecting joint of cantilevered handrails is an issue that needs to be improved. In this study, the armrest joints of a cantilever armchair made by beech (Fagus orientalis Lipsky) were examined. To improve the mechanical strength of handrail joints, three novel joints were proposed including dovetail tenon, cross-stepped tenon, and rear plug corner tenon. The finite element analysis (FEA) was used to compare and analyze the five joints to obtain the optimal joint. Finally, experimental tests were conducted to verify the results of the FEA. The novel cross-stepped tenon had better mechanical performance, i.e., bending moment capacity and stiffness, than other joints evaluated. The maximum load of the novel cross-stepped tenon was greater than that of the commonly used tenon. In conclusion, the cross-stepped tenon was most suitable for cantilevered handrail joint of chair. This study will contribute to the structural design of modern solid wooden chairs.

The mechanical and acoustic properties of four commonly used wood species, including poplar (Populus tomentosa), mahogany (Swietenia mahagoni), beech (Fagus orientalis), and Ash (Fraxinus excelsior) wood were investigated through using three-point bending and notched bending tests synchronizing with power spectrum analysis method and fractal dimension theory. The results showed that the bending modulus of elasticity and modulus of rapture changed in the same trend with the order ranging from high to low was ash, beech, poplar and mahogany, successively. The brittle fracture occurred in mahogany samples and ductile fracture raised in the other three wood species. Positive proportional correlation was observed between maximum acoustic pressure and fractal dimension of power spectrum regardless of seeing four wood species as independent or population samples. The failure modes can be identified by amplitude-frequency curve and fractal dimension of power spectrum with following laws: the peak value in amplitude-frequency curve and fractal dimension of power spectrum were relatively higher when a single crack developed at latewood; for crack developed at earlywood, only one peak was observed in power amplitude-frequency curves, and the corresponding fractal dimension of power spectrum was smaller than the that of latewood; in case of failure modes with two cracks developed at earlywood, there are two peaks in amplitude-frequency curve and the fractal dimension of power spectrum was between those of single crack developed at earlywood and latewood. The vibrational properties of the four wood species can be characterized through using power spectrum analysis method and notched bending test method can be used to distinguish the failure modes of samples.

Furniture as a functional object must satisfy both artistic and scientific requirements. In particular, ergonomic factors are very important in furniture design in terms of human health and productivity. To make furniture designs at the ideal intersection of science and art, it is necessary to approach furniture design with a scientific systematic. Accordingly, this paper summarizes and analyzes the current state of biomechanics in ergonomic furniture design, covering an overview of the biomechanics utilized in different types of furniture design, biomechanical analysis, and testing methods. In the conclusion of the study, the literature analysis identifies the key topics and areas of future exploration regarding the use of biomechanics in ergonomic furniture design. The findings of the review indicate that (1) the primary studies on biomechanics used in furniture design concentrate on special furniture, such as wheelchairs and transportation vehicle seats, with minimal investigation performed on common furniture; (2) mechanical analysis, experimental testing, and computer-aided ergonomics represent the main techniques applied in furniture design biomechanics; (3) the reliability of biomechanics used in furniture design needs to be improved due to the lack of fundamental parameters of the muscles and skeleton of the human body; and (4) more attention should be paid to the use of biomechanics in the design of common furniture, such as household and office furniture, which affects people’s health and comfort. The scientific and rational application of biomechanics should be integrated into ergonomic furniture design to promote healthy living and enhance work efficiency.

Abstract Ureteral stent removal by an extraction string is advantageous. However, the increased risk of complications attributed to the continuous exposure of the string outside the urethra must be managed. This paper introduces a method to decrease the exposure time, and conducts a retrospective study to verify its efficiency and safety. A total of 231 male patients undergoing routine ureteroscopy (URS) were included, and all of them accepted indwelling ureteral stents with strings. Among them, 123 patients (Normal-S group) underwent the normal method to determine the length of string (Lstring), which was shortened to 4 cm (cm) past the urethral meatus; 108 patients (Novel-S group) underwent the novel method (Lstring = Lurethra + 2 cm), the length of urethra (Lurethra) was measured during ureteroscopy by ureteroscope body. The demographic characteristics, stent indwelling and removal-related variables, complications, and medical costs in each group were recorded. There was no significant difference in demographic characteristics, the rate of UTI, the operative duration of URS, or the VAS pain scores for stent removal between the 2 groups. For the Novel-S group, the stent dwelling time was longer, the self-rated discomfort and symptom, the stent dislodgement rate, the numbers of clinic or emergency visits and the overall medical cost post operation was lower in comparison with the Normal-S group, while the rate of removal of stents by hand was lower, the time for removing ureteral stents was longer. This novel method improved stenting comfort, avoided ureteral stent dislodgement, decreased complications, and lowered medical costs, it was safe and reliable and merits widespread application.

Abstract The static lateral load–slip behavior of a single-shear plywood-to-plywood single-staple connection (SPSC) was investigated experimentally. A mechanics-based approach was used to develop mechanical models for deriving estimation equations for critical lateral loads of SPSCs based on failure modes of staple legs and connection member materials developed during static lateral loading process. Experimental results indicated that the static lateral load–slip behavior of SPSCs can be characterized with three major stages. This experiment provided the evidence that the ultimate lateral load capacity of SPSCs was partially governed by staple direct withdrawal load capacity in main members. The proposed mechanical models were verified experimentally as a valid means for deriving estimation equations for critical lateral loads of SPSCs evaluated in this study.

For the skin immune system, γδ T cells are important components, which help in defensing against damage and infection of skin. Compared to the conventional αβ T cells, γδ T cells have their own differentiation, development and activation characteristics. In adult mice, dendritic epidermal T cells (DETCs), Vγ4 and Vγ6 γδ T cells are the main subsets of skin, the coordination and interaction among them play a crucial role in wound repair. To get a clear overview of γδ T cells, this review synopsizes their derivation, development, colonization and activation, and focuses their function in acute and chronic wound healing, as well as the underlining mechanism. The aim of this paper is to provide cues for the study of human epidermal γδ T cells and the potential treatment for skin rehabilitation.

The work simulates the transport pipeline movement of the marine dynamic environment based on the computational fluid dynamics research method. The present work also studies the influence of the marine dynamic environment on the solid–liquid two-phase flow field in the pipeline. An experimental study on the hydraulic transport flow law of natural gas hydrate pipeline is performed on the experimental platform of deep-sea mining metallogenic system fluctuation. Results show a large disturbance of the transverse swing convection field of pipelines and a small influence of axial vibration. The flow field distribution characteristics in the conveyor pipeline are consistent with the steady-state working conditions when the amplitude of transverse oscillation is less than 0.5 m. When the oscillation amplitude is larger than 2 m, the vibration has a considerable influence on the solid-phase distribution, solid–liquid two-phase velocity, dynamic and static pressure, and pressure loss of the flow field in the conveying system. The flow field distribution is chaotic when the transverse oscillation period of the pipeline is small. This condition becomes highly evident when the oscillation amplitude is large.

Abstract Background The intestinal barrier integrity can be disrupted due to burn injury, which is responsible for local and systemic inflammatory responses. Anti-inflammation strategy is one of the proposed therapeutic approaches to control inflammatory cascade at an early stage. Interleukin-17A (IL-17A) plays a critical role in inflammatory diseases. However, the role of IL-17A in the progression of burn-induced intestinal inflammation is poorly understood. In this study, we aimed to investigate the effect of IL-17A and associated pro-inflammatory cytokines that were deeply involved in the pathogenesis of burn-induced intestinal inflammatory injury, and furthermore, we sought to determine the early source of IL-17A in the intestine. Methods Mouse burn model was successfully established with infliction of 30% total body surface area scald burn. The histopathological manifestation, intestinal permeability, zonula occludens-1 expression, pro-inflammatory cytokines were determined with or without IL-17A-neutralization. Flow cytometry was used to detect the major source of IL-17A+ cells in the intestine. Results Burn caused intestinal barrier damage, increase of intestinal permeability, alteration of zonula occludens-1 expressions, elevation of IL-17A, IL-6, IL-1β and tumor necrosis factor-α (TNF-α), whereas IL-17A neutralization dramatically alleviated burn-induced intestinal barrier disruption, maintained zonula occludens-1 expression, and noticeably, inhibited pro-inflammatory cytokines elevation. In addition, we observed that the proportion of intestinal IL-17A+Vγ4+ T subtype cells (but not IL-17A+Vγ1+ T subtype cells) were increased in burn group, and neutralization of IL-17A suppressed this increase. Conclusions The main original findings of this study are intestinal mucosa barrier is disrupted after burn through affecting the expression of pro-inflammatory cytokines, and a protective role of IL-17A neutralization for intestinal mucosa barrier is determined. Furthermore, Vγ4+ T cells are identified as the major early producers of IL-17A that orchestrate an inflammatory response in the burn model. These data suggest that IL-17A blockage may provide a unique target for therapeutic intervention to treat intestinal insult after burn.

The effects of low molecular weight phenol formaldehyde resin on weathering durability property of sweetgum (Liquidambar styraciflua) and southern pine (Pinus taeda) specimens were studied using six wet-dry cycles with ultraviolet light accelerated weathering test following ASTM D2898-10 via evaluating the water repellent efficiency, dimensional stability, and crack formation of wood. The results showed that 1) the water repellent efficiency of treated quarter-sawn sweetgum specimens was higher than those of treated quarter-sawn and flat-sawn southern pine specimens; 2) the dimensional stabilities of sweetgum and southern pine specimens were all improved by impregnating low molecular weight phenol formaldehyde resin, especially for sweetgum; 3) there were clearly more cracks on exposed ends and surfaces of all treated sweetgum and southern pine specimens than those on control ones, indicating that the low molecular weight phenol formaldehyde resin modification used in this study were not able to improve the anti-cracking properties of sweetgum and southern pine specimens. Generally, the sweetgum was more suitable to be impregnated with low molecular weight phenol formaldehyde resin than southern pine with the procedure described according to dimensional stability and water repellent efficiency, in order to improve the weathering durability.

The effect of loading type (tension, compression and bolt-bearing) on mechanical properties (elastic modulus, Poisson’s ratio and ultimate strength) of Moso bamboo (Phyllostachys heterocycla var. pubescens) in longitudinal direction was evaluated in this study. In addition, experimental and numerical tests were conducted to evaluate withdrawal force capacity and bending moment resistances of a novel demountable bamboo-bolt joint considering effect of loading type on mechanical parameters used in finite element method. The results showed that 1) loading type had significant effect on mechanical properties of Moso bamboo, especially, for ultimate strength; 2) the values of mechanical properties evaluated in this study measured in tension were all much higher than those measured in bolt-bearing state and followed by compression accordingly; 3) in tension, the tensile elastic modulus and Poisson’s ratio measured at outer surface were bigger than those at inner surface, respectively; 4) finite element method got more accurate results using the mechanical parameters measured in compression than those in tension and bolt-bearing states; 5) the bamboo-bolt joint proposed in this study can be used in lightweight bamboo structures through improving the embedding strength of beech wood in bamboo culm. In conclusion, one should consider the loading type used to obtain the mechanical parameters inputted in finite element method. In addition, further studies will focus on effect of size and geometry of samples used to determine mechanical properties used in finite element method, and the method of improving embedding strength of beech wood in bamboo culm to increase withdrawal force capacity and bending moment resistances of the demountable bamboo-bolt joint proposed in this study.

The fracture behaviors of four wood species commonly used in wood products were characterized when subjected to compact tension (CT) load in radial-longitudinal (RL) system crack propagation. Meanwhile, the failure modes of evaluated CT samples were compared and analyzed using the fractal dimension method. The results showed that wood species had a significant effect on fracture characteristic values, including maximum fracture load, critical stress intensity factor and fracture energy. These characteristic values changed in the same way, i.e., beech wood CT samples obtained the maximum characteristic values, followed by ash, okoume, and poplar in descending order. The fracture behaviors of all wood species evaluated can be described by combining linear and exponential fitting equations at the crack initial stage and evolution stage, respectively. Linear positive proportional relationships were observed between fracture characteristic values and fractal dimensions calculated using cracks in front and left views of CT samples. However, the relationships between fracture characteristic values and fractal dimensions calculated using fracture surfaces were negative. The fractal dimensions of cracks in front view of CT samples could be a better indicator used to predict critical stress intensity factor and fracture energy, which had greater correlation coefficients beyond 0.95.

For a long time, the geometry dimensions of tenons have been designed through empirical methods, which is not beneficial to designers and manufacturers and results in more time spent in construction and a greater amount of waste wood materials. In this study, an optimal methodology of combining finite element analysis (FEA) with response surface method (RSM) was proposed to investigate the effect of tenon geometric dimensions (length, width, and thickness) on withdrawal and bending load capacities of mortise-and-tenon (M-T) joints, with the aim of making the design of wood products more scientific. The following results were concluded: (1) the effect of tenon length on withdrawal load capacity was greater than tenon thickness, followed by tenon width; (2) the effect of tenon thickness on bending load capacity was greater than those of tenon width, followed by tenon length; (3) it was concluded that the tenon length should be designed to be greater than the tenon width and smaller than twice the tenon width, especially, when tenon thickness was relatively thin; (4) quadratic models can be used to predict the withdrawal and bending load capacities of M-T joints relating the length, width, and thickness of the tenon; (5) the proposed method was capable of being used to optimize the tenon sizes and get more knowledge of M-T joints visually. This study will contribute to reducing the costs of time and materials, and it will result in M-T joints being designed more rationally.

The effect of impregnation treatment of low molecular weight phenol formaldehyde (MWPF) resin on the bolt-bearing yield strength (BBYS) of a three-layered cross-laminated timber (CLT) composed of two face layers of southern pine (Pinus taeda) and one core layer of sweetgum (Liquidambar styraciflua) was investigated together with two additional factors of material type and loading direction. Experimental results indicated that the amount of low MWPF resins penetrating into sweetgum was more than the ones into southern pine. Sweetgum had more uniform distribution of low MWPF resins penetrating longitudinally than southern pine. Impregnation treatment using a low MWPF resin at a concentration of 20% can enhance the BBYS of three-layered CLTs with a 60% increase. The BBYS of a core layer material in three-layered CLTs can significantly alter the overall BBYS of the three-layered CLTs.

Mortise-and-tenon (M–T) joint is a traditional joint type commonly used in wood constructions and wood products. Bending moment capacity (BMC) is a critical criterion to evaluate the strength of the M–T joint. In order to design the M–T joint structure more rationally, many researchers have been devoted to studying on this topic. However, the factors influencing the BMC are too many to conduct comprehensive studies using experimental tests, especially for tenon size. In this study, the BMC and bending stiffness of the M–T joint were studied using a combination of finite element method (FEM) and response surface method to optimize the tenon size of the M–T joint. The results showed that (1) the proposed finite element model was capable of predicting BMC of M–T joints with the ratios of FEM to observed, ranging from 0.852 to 1.072; (2) the BMC and stiffness were significantly affected by tenon size, and tenon length had a more significant effect on BMC than tenon width, while the tenon width affected the bending stiffness more significantly; (3) the response surface model proposed to predict and optimize the BMC of the M–T joint relating to tenon length and tenon width was capable of providing an optimal solution; (4) it was recommended to make the ratio of tenon length to tenon width higher than 1 to get higher BMC of M–T joints. In conclusion, this study will contribute to reducing the cost of a huge amount of experimental tests by applying FEM and the response surface method to design M–T joint wood products.

Withdrawal resistance of the mortise-and-tenon (M&T) joint is an important indicator to evaluate the strength of the M&T joint. Generally, the T-shaped specimen is usually used to measure withdrawal resistance using tensile methods, but there has not been testing standard until now. In this study, the methods of measuring withdrawal resistance of the M&T joint were investigated systematically. A new method used to determine the withdrawal resistance of M&T joint was proposed to be named as the compressive method. In addition, withdrawal resistances of M&T joint determined using tensile and compressive methods were compared based on experiments and the finite element method (FEM). The experimental results showed that the effects of the testing method and glue on withdrawal resistance of M&T joint were statistically significant, specifically, the withdrawal resistance measured using tensile method was higher than the one determined by the compressive method. Meanwhile, the results of FEM also confirmed the experimental results in a visible way. The results of FEM indicated that the withdrawal resistance of the M&T joint was influenced by tenon member length; specifically, the withdrawal resistance of the M&T determined by tensile method increased with the increasing of tenon member length. In summary, the results of the study make sense in the measurement of withdrawal resistance of the M&T joint in practice, and in f theory, the study will contribute to instructing the design of furniture structures.

Elastic constants of wood are fundamental parameters used in finite element analysis of wood structures. However, few studies and standards regulate the dimensions of sample used to measure elastic constants of wood. The size effect on mechanical properties (i.e., elastic constants and proportional limit stresses) of European beech (Fagus sylvatica L.) wood was studied with five different sizes samples. The data of experiments were inputted into a finite element model of self-designed chair and the loading capacity of chair was investigated by finite element method (FEM) and experiment. The results showed that nonlinear relationships were found between proportional limit stresses, cross-sectional area, and height of specimen by response surface method with R2 greater than 0.72 in longitudinal, radial, and tangential directions. Elastic moduli and shear moduli increased with the height of specimen when cross-sectional area was kept constant, and decreased with an increased cross-sectional area of specimen, when the height was a constant, while the trends of Poisson’s ratio were not as expected. The comparisons between experiment and FEM suggested that the accuracy of FEM simulation increase with the raise of width-height ratio (≤1) of specimens used to determine the elastic constants. It is recommended to use small cubic wood specimen to determine the elastic mechanical properties used for finite element analysis of beech wood structures. Further research to find optimized wood specimen dimensions to get mechanical properties for FEM is quite necessary.

Modern solid wood armchairs are developing in the direction of simplicity and lightness, and favored by the market. However, the low mechanical strength of the connecting joint of cantilevered handrails is an issue that needs to be improved. In this study, the armrest joints of a cantilever armchair made by beech (Fagus orientalis Lipsky) were examined. To improve the mechanical strength of handrail joints, three novel joints were proposed including dovetail tenon, cross-stepped tenon, and rear plug corner tenon. The finite element analysis (FEA) was used to compare and analyze the five joints to obtain the optimal joint. Finally, experimental tests were conducted to verify the results of the FEA. The novel cross-stepped tenon had better mechanical performance, i.e., bending moment capacity and stiffness, than other joints evaluated. The maximum load of the novel cross-stepped tenon was greater than that of the commonly used tenon. In conclusion, the cross-stepped tenon was most suitable for cantilevered handrail joint of chair. This study will contribute to the structural design of modern solid wooden chairs. [ABSTRACT FROM AUTHOR]

Abstract The stellar optoelectronic properties of metal halide perovskites provide enormous promise for next-generation optical devices with excellent conversion efficiencies and lower manufacturing costs. However, there is a long-standing ambiguity as to whether the perovskite surface/interface (e.g. structure, charge transfer or source of off-target recombination) or bulk properties are the more determining factor in device performance. Here we fabricate an array of CsPbI3 crystal and hybrid glass composites by sintering and globally visualise the property-performance landscape. Our findings reveal that the interface is the primary determinant of the crystal phases, optoelectronic quality, and stability of CsPbI3. In particular, the presence of a diffusion “alloying” layer is discovered to be critical for passivating surface traps, and beneficially altering the energy landscape of crystal phases. However, high-temperature sintering results in the promotion of a non-stoichiometric perovskite and excess traps at the interface, despite the short-range structure of halide is retained within the alloying layer. By shedding light on functional hetero-interfaces, our research offers the key factors for engineering high-performance perovskite devices.

The effects of low molecular weight phenol formaldehyde resin on weathering durability property of sweetgum (Liquidambar styraciflua) and southern pine (Pinus taeda) specimens were studied using six wet-dry cycles with ultraviolet light accelerated weathering test following ASTM D2898-10 via evaluating the water repellent efficiency, dimensional stability, and crack formation of wood. The results showed that 1) the water repellent efficiency of treated quarter-sawn sweetgum specimens was higher than those of treated quarter-sawn and flat-sawn southern pine specimens; 2) the dimensional stabilities of sweetgum and southern pine specimens were all improved by impregnating low molecular weight phenol formaldehyde resin, especially for sweetgum; 3) there were clearly more cracks on exposed ends and surfaces of all treated sweetgum and southern pine specimens than those on control ones, indicating that the low molecular weight phenol formaldehyde resin modification used in this study were not able to improve the anti-cracking properties of sweetgum and southern pine specimens. Generally, the sweetgum was more suitable to be impregnated with low molecular weight phenol formaldehyde resin than southern pine with the procedure described according to dimensional stability and water repellent efficiency, in order to improve the weathering durability. [ABSTRACT FROM AUTHOR]

The effects of the moisture content, density, and striking direction of a hammer on the vibrational characteristics, i.e., the fundamental frequency and dynamic modulus of elasticity, of four wood species, i.e., poplar (Populus tomentosa), mahogany (Swietenia mahagoni), beech (Fagus orientalis), and ash (Fraxinus excelsior), commonly used in wood products were investigated, aiming to provide basic evidence for the nondestructive testing of wood materials. The results showed that the effect of the wood species on the fundamental frequency, dynamic modulus of elasticity, and static modulus of elasticity was statistically significant. The dynamic moduli of elasticity of the four wood species were higher than the corresponding static moduli of elasticity. The effect of the striking direction on the dynamic modulus of elasticity was not significant, indicating that no matter where the hammer struck, i.e., radial and tangential surfaces, the fundamental frequency was essentially constant. Negative relationships were found between the fundamental frequency and the density and moisture when the data of the four wood species were viewed as a population sample. The vibrational characteristics of each wood species varied, which can be applied to the nondestructive testing of wood. [ABSTRACT FROM AUTHOR]

Abstract The past few decades have seen increasingly rapid advances in the field of sustainable energy technologies. As a new bio‐ and eco‐friendly energy source, enzymatic biofuel cells (EBFCs) have garnered significant research interest due to their capacity to power implantable bioelectronics, portable devices, and biosensors by utilizing biomass as fuel under mild circumstances. Nonetheless, numerous obstacles impeded the commercialization of EBFCs, including their relatively modest power output and poor long‐term stability of enzymes. To depict the current progress of EBFC and address the challenges it faces, this review traces back the evolution of EBFC and focuses on contemporary advances such as newly emerged multi or single enzyme systems, various porous framework‐enzyme composites techniques, and innovative applications. Besides emphasizing current achievements in this field, from our perspective part we also introduced novel electrode and cell design for highly effective EBFC fabrication. We believe this review will assist readers in comprehending the basic research and applications of EBFCs as well as potentially spark interdisciplinary collaboration for addressing the pressing issues in this field.