Numerical Analysis and Quantification of Transfer Efficiency Coupled with Capillary and Quadrupole Ion Guide in an API-MS System.

Ion trajectory simulation is a significant and useful tool for understanding ion transfer mechanisms within the first vacuum region of the atmospheric pressure ionization mass spectrometer (API-MS). However, the complex dynamic gas field and wide pressure range lead to inaccurate simulation and huge computational costs. In this work, a novel electrohydrodynamic simulation called the statistical diffusion-hard-sphere (SDHS) mixed collision model was developed for characterizing the ion trajectories. For the first time, the influence of the dynamic pressure on the ion trajectory is considered for simulation, which helps to avoid an intolerable computational cost. Comparing with the conventional Monte Carlo collision model, the SDHS method helps to improve the calculation accuracy of ion trajectories under the first vacuum region and reduce the computational cost for at least 12-folds. Simulation results showed that the maximum ion loss came from the gap of the electrodes. The distance of the capillary-quadrupole ion guide was also a non-negligible factor. The trend of quantitative experimental results matches the SDHS simulation results. The maximum ion transfer efficiencies of quantitative experiment and simulation were 55% and 52%, respectively. Moreover, three ions, caffeine, reserpine, and Ultramark 1621, were measured for evaluating the applicability of SDHS in real API-MS. The trend of experimental results showed good agreement with that of computation. And the results of caffeine further illustrated the reason that the small mass ion transfer efficiency decreased with increasing radio frequency voltage. SDHS method is expected to be useful in the design of ion guides for further improvement of the sensitivity of API-MS.

Prognostic value of PD-L1 expression in patients with anal cancer: a meta-analysis.

Background: The present meta-analysis was performed to evaluate the prognostic and clinicopathological significance of PD-L1 in anal cancer (AC). Methods: Hazard ratios (HRs) and 95% CIs regarding overall survival (OS) and progression-free survival (PFS) were calculated based on PD-L1 levels. Results: According to the combined data, PD-L1 showed no significant relationship with OS (HR = 0.76; 95% CI = 0.35-1.67; p = 0.502) or PFS (HR = 0.88; 95% CI = 0.35-2.33; p = 0.789) in patients with AC. Based on subgroup analysis, PD-L1 overexpression significantly predicted prolonged OS (HR = 0.38; 95% CI = 0.17-0.84; p = 0.017) in tumor node metastasis stages I-III and inferior PFS (HR = 2.73; 95% CI = 1.32-5.65; p = 0.007) in patients with stage I-IV AC. Conclusion: PD-L1 level assessed by immunohistochemistry did not significantly predict survival outcomes in AC cases.

Structural and mechanical characterization of the hoof in Mongolian equids.

In this paper, the microstructure and mechanical properties (including nanoindentation, tensile test, and compression test) of Mongolian horse hooves were investigated. Many tubules and Intermediate Filaments (IF) were distributed longitudinally in the hoof of Mongolian horses, which could better help the hoof cushioning. The hardness and modulus of the hoof wall of Mongolian horses varied at different water contents. The hardness and modulus decreased with the increase in water content. The modulus of elasticity of the hoof wall decreased from 16.3% to 25.4%, and the hardness decreased from 17.8% to 29.3% from 10% to 20% water content. At 20-30% water content, the horseshoe wall modulus decreased by 3.5%-4.8%, and the hardness reduced by 4.1%-7.3%. The results of the tensile and compression experiments showed that the compression properties of Mongolian horse hooves were better than their tensile properties; their longitudinal compression energy absorption was better than their transverse compression properties; and Young's modulus and yield strength of the hoof wall increased as the compression rate increased. Finally, comparing the experiments belonging to this paper with hooves from other papers, it was found that the hardness of the tubular region and the intertubular region of Mongolian horse hooves was 17.7% and 39.4% higher than that of the hooves from the current study, respectively. The microstructural features of Mongolian horse-like hooves with superior mechanical properties provide a promising inspiration for the bionic design of lightweight and high-strength composites in engineering.

Comparative Analysis of Macro/Microstructures and Constituents of Sorghum and Reed Straw.

Node-containing straws exhibit superior mechanical properties compared to node-free straw plants, particularly in terms of shear resistance and compression resistance. We explore the relationship between the structure and mechanical properties of straw materials, providing deeper insights for the field of biomechanics. In this study, we focused on two node-containing straw plants, namely sorghum and reed. The main characteristics of sorghum and reed stalks were compared using macroscopic observation, stereomicroscopy, scanning electron microscopy, infrared spectroscopy, and EDS analysis. This study revealed numerous similarities and differences in the macro- and microstructures as well as the elemental composition of sorghum and reed stalks. The functional groups in sorghum and reed stalks were largely similar, with the primary elements being C and O. Distinguishing features included a higher tapering and a slightly larger reduction in wall thickness in sorghum stalks compared to reed stalks. The cross-section of sorghum stalks was filled with pith structures, while reed stalks exhibited a hollow structure. The vascular bundles in sorghum typically showed a paired arrangement, whereas those in reeds were arranged in odd numbers. Furthermore, sorghum straws contained more Cl and no Br, while the parenchyma of reed straws contained higher Br. The C and O proportions of sorghum straws and reed straws are 50-53% (50-51%) and 45-46% (48-49%), respectively. These variations in elemental composition are believed to be correlated with the mechanical properties of the materials. By conducting a detailed study of the micro/macrostructures and material composition of sorghum and reed straw, this paper provides valuable insights for the field of biomechanics.

Monitoring walking asymmetries and endpoint control in persons living with chronic stroke: Implications for remote diagnosis and telerehabilitation.

Objective: The objective of this study was to assess the feasibility of monitoring and diagnosing compromised walking motion in the frontal plane, particularly in persons living with the chronic effects of stroke (PwCS). The study aimed to determine whether active control of walking in the frontal plane could be monitored and provide diagnostic insights into compensations made by PwCS during community living. Methods: The study recruited PwCS with noticeable walking asymmetries and employed a monitoring method to assess frontal plane motion. Monitoring was conducted both within a single assessment and between assessments. The study aimed to uncover baseline data and diagnostic information about active control in chronic stroke survivors. Data were collected using sensors during 6 minutes of walking and compared between the paretic and non-paretic legs. Results: The study demonstrated the feasibility of monitoring frontal plane motion and diagnosing disturbed endpoint control (p < 0.0125) in chronic stroke survivors when comparing the paretic leg to the non-paretic leg. A greater variability was observed in the paretic leg (p < 0.0125), and sensors were able to diagnose a stronger coupling of the body with its endpoint on the paretic side (p < 0.0125). Similar results were obtained when monitoring was conducted over a six-minute walking period, and no significant diagnostic differences were found between the two monitoring assessments. Monitoring did not reveal performance fatigue or debilitation over time. Conclusions: This study's findings indicate that monitoring frontal plane motion is a feasible approach for diagnosing compromised walking motion. The results suggest that individuals with walking asymmetries, exhibit differences in endpoint control and variability between their paretic and non-paretic legs. These insights could contribute to more effective rehabilitation strategies and highlight the potential for monitoring compensations during various activities of daily living.

Biomimetic Study of a Honeycomb Energy Absorption Structure Based on Straw Micro-Porous Structure.

In this paper, sorghum and reed, which possess light stem structures in nature, were selected as biomimetic prototypes. Based on their mechanical stability characteristics-the porous structure at the node feature and the porous feature in the outer skin- biomimetic optimization design, simulation, and experimental research on both the traditional hexagonal structure and a hexagonal honeycomb structure were carried out. According to the two types of straw microcell and chamber structure characteristics, as well as the cellular energy absorption structure for the bionic optimization design, 22 honeycomb structures in 6 categories were considered, including a corrugated cell wall bionic design, a modular cell design, a reinforcement plate structure, and a self-similar structure, as well as a porous cell wall structure and gradient structures of variable wall thickness. Among them, HTPC-3 (a combined honeycomb structure), HSHT (a self-similar honeycomb structure), and HBCT-257 (a radial gradient variable wall thickness honeycomb structure) had the best performance: their energy absorption was 41.06%, 17.84%, and 83.59% higher than that of HHT (the traditional hexagonal honeycomb decoupling unit), respectively. Compared with HHT (a traditional hexagon honeycomb decoupling unit), the specific energy absorption was increased by 39.98%, 17.24%, and 26.61%, respectively. Verification test analysis revealed that the combined honeycomb structure performed the best and that its specific energy absorption was 22.82% higher than that of the traditional hexagonal structure.

Study on driver's active emergency response in dangerous traffic scenes based on driving simulator.

OBJECTIVE: A driver's active emergency response in dangerous traffic scenes consists of two parts, including reaction behavior and physiological state. In dangerous traffic scenes, the driver's active emergency response has an important impact on human collision injury. Clarifying the driver's active emergency response is an important prerequisite for the study of human collision injury under nonstandard posture. Therefore, this study investigates the driver's active emergency response in different inevitable collision scenes using driving simulator. METHODS: A driving simulator with a high-speed camera system and human physiological signal acquisition system was first built. Then, three typical vehicle dangerous collision scenes were developed, including frontal collision, side collision, and rear-end collision. Finally, twenty participants (15 males and 5 females) were recruited for a driving experiment, and their active emergency responses were recorded and analyzed. RESULTS: All subjects would rotate the steering wheel to the left or right in the active emergency state, and the rotation of the hand would also cause the subject's upper body to tilt in the same direction. The maximum angle for male subjects to rotate the steering wheel was 59.98°, while for the female subjects, it was 44.28°. In addition, the maximum grip force between the male subjects and the steering wheel was 280.5 N, compared to 192.5 N for female subjects. Compared to the female participants, the male participants not only have a greater rotation angle and a greater grip force on the steering wheel, but also have greater pressure on the brake pedal, and the foot moves quickly from the accelerator pedal to the brake pedal and presses the brake pedal. CONCLUSIONS: Drivers have different active emergency responses to different vehicle collision scenes. Quantitative statistics of driver's active emergency response will have important guiding significance for the analysis of the impact of human active emergency response on human injury characteristics in subsequent vehicle collision experiments.

The potentially dangerous zone of the dorsomedial cutaneous nerve in minimally invasive surgery for hallux valgus: a cadaveric study.

BACKGROUND: This study aims to describe the distribution of the dorsomedial cutaneous nerve (DMCN) in the middle and proximal parts of the metatarsal from a lateral view. The purpose is to provide guidance to surgeons in protecting the nerve during the 3rd and 4th generation minimally invasive surgery (MIS) for hallux valgus (HV). METHODS: A total of 20 cadaveric feet were dissected to expose the course of the DMCN and sentinel vein. Measurements of the distances between the nerve/vein and the upper border of the metatarsal, as well as the height of the metatarsal, were taken from a lateral view. The distribution area was then described in proportion. RESULTS: At the base of the metatarsal, the DMCN was distributed in the upper 25.7% of the area. When it reached the middle of the metatarsal, the DMCN was distributed in the upper 13.2-47.2% of the area. As for the sentinel vein, it was distributed in the upper 23.5-71.9% and upper 4.1-52.7%, respectively, at these two positions. CONCLUSIONS: The area, which is above the line connecting the upper 1/4 point at the base of the first metatarsal and the 1/2 point at the middle of the first metatarsal, is a dangerous zone for the DMCN. Avoiding the zone is recommended during MIS for HV.

Research on Impact Resistance of Aluminum Alloy New Rotating Thin-Walled Structures.

Honeycomb structures are widely used in the field of impact resistance and are constantly being developed and updated. In this paper, the design of three new aluminum alloy rotating thin-walled structures (NRTS) are examined. These structures combine common concave structures and rotating, rigid-body structures. The purpose of this study is to solve the problem of the poor energy absorption capacity of rotating, rigid-body structure due to small deformation and to provide a reference for honeycomb mechanism designs. The Young's modulus, the critical velocity, and the platform stress of the NRTS structure are derived from theoretical analysis. The dynamic response of the NRTS structure at different impact velocities is investigated using finite element simulation software. The results show that the rotating, thin-walled recessed honeycomb (RTRH) increases the plateau stress by 124% and 51% as compared to rotating, thin-walled square tubes (RTSTs) and the re-entrant hexagonal structure (RH), respectively; the rotating, thin-walled quadruple-arc honeycomb structure (RTQH) increases the SEA by 21% and 20% as compared to the RTST and RH, respectively; and the rotating thin-walled double-arc honeycomb structure (RTDH) increases the CEF by 54% and 51% as compared to the RTST and RH, respectively. During the study, it was demonstrated that NTRS also exhibits good energy absorption capacity. Then, the effect of rotation angle on the energy absorption performance was analyzed. The cell and wall thickness of the NTRS structure were optimized according to the gradient theory. It was proved that the gradient optimized structure has better energy absorption performance as compared to the uniform structure.

Foot Bionics Research Based on Reindeer Hoof Attachment Mechanism and Macro/Microstructures.

The attachment performances of mechanical feet are significant in improving the trafficability and mobility of robots on the extreme ground. In the future, frozen-ground robots can be used to replace human soldiers in scouting and deep space exploration. In this study, the influence factors on the attachment function of the bionic feet were analyzed. Soft frozen soil and tight frozen soil close to natural frozen soil were prepared, and the friction between ungula and frozen soil ground was simulated together with the plantar pressures of reindeer under trotting. The major attachment parts were the ungula cusp, outer edges, and ungula capsules, and the stress on the ungula was mainly 4.56-24.72 MPa. According to the microstructures of plantar fur and ungula, the corresponding ratio of the rib width and length was 0.65:1, and the corresponding ratio of the rib width and distance was 3:1. In addition, the scales of the plantar fur were very tightly arranged and had large ripples. Based on typical curves, an ungula capsule-curved surface, and a nonsmooth plantar fur surface, four types of bionic feet and the corresponding ordinary multidamboard foot were designed. On the frozen soil, the bionic foot with ribs and an ungula capsule showed the best attachment performance. Compared with the multidamboard foot, the dynamic coefficient of friction of the bionic foot with ribs and ungula capsules increased by 11.43-31.75%. The attachment mechanism of the bionic feet is as follows: under the action of pressure, the fine patterns of the bionic convex-crown generate friction with the nonsmooth structure of the frozen soil surface, which improves the attachment performance.

PLA2G12B Mediates Arachidonic Acid Metabolism through Activation of the NF-κB Pathway to Promote Membrane Nephropathy.

INTRODUCTION: The disruption of podocyte structure and function are the main pathological mechanism of membranous nephropathy (MN). Phospholipases A2, Group XII B (PLA2G12B) was reported involved in the regulation of MN by interfering with arachidonic acid (AA) metabolism, but there is a lack of sufficient evidence. In this study, we investigated the role and molecular mechanism of PLA2G12B in MN. METHODS: C57BL/6 mice were used to establish MN model to extract primary podocytes, then divided into control, model, si-phospholipases A2 receptor (PLA2R), PLA2G12B, PLA2G12B + si-PLA2R, PLA2G12B + nuclear factor kappa-B (NF-κB) inhibitor, PLA2G12B + NF-κB inhibitor + si-PLA2R groups. Hematoxylin-eosin staining and immunofluorescence were used to detect kidney histological arrangement, serum levels of cholesterol-related indices, and AA. Genes and proteins associated with metabolism and inflammatory factors were detected by quantitative real-time PCR and Western blot. RESULTS: The results revealed that AA metabolites were activated in the MN model mice, and the expression of PLA2G12B and NF-κB pathway levels were elevated. Besides, cellular experiments demonstrated that prostaglandin I2 (PGI2), thromboxane A2 (TXA2), leukotriene B4 (LTB4), and NF-κB pathway were significantly increased in the PLA2G12B group. Also, PLA2G12B promotes apoptosis and suppresses cell activity in podocytes, and these effects could be antagonized by NF-κB inhibitors. Furthermore, with the inference of si-PLA2R, the NF-κB inhibitors' effects were reversed. CONCLUSION: Promotional effects of PLA2G12B in primary MN are associated with the regulation of AA metabolism and NF-κB pathway.

[Short-term effectiveness of calcaneal lateral displacement osteotomy with lateral ligament repair in treatment of Takakura stage â ¡ varus-type ankle arthritis].

Objective: To investigate the short-term effectiveness of calcaneal lateral displacement osteotomy with lateral ligament repair in the treatment of Takakura stage Ⅱ varus-type ankle arthritis. Methods: A retrospective analysis was performed on the clinical data of 13 patients with Takakura stage Ⅱ varus-type ankle arthritis treated with calcaneal lateral displacement osteotomy with lateral ligament repair between January 2016 and December 2020. There were 6 males and 7 females aged 31-65 years, with an average age of 53.6 years. The preoperative tibial-ankle surface angle (TASA) was (88.13±1.01)°, medial distal tibial angle (MDTA) was (86.36±1.49)°, tibial talar surface angle (TTSA) was (6.03±1.63)°, talar tilting angle (TTA) was (81.95±2.15)°, and tibiocalcaneal axis angle (TCAA) was (-5.74±6.81)°. The preoperative American Orthopedic Foot and Ankle Society (AOFAS) score was 56.3±7.1 and the pain visual analogue scale (VAS) score was 3.7±0.5. AOFAS scores, VAS scores, TTSA, TTA, and TCAA were compared between pre- and post-operatively. Results: All 13 patients were followed up 14-41 months, with an average of 28.7 months. The osteotomies healed in all patients. The last follow-up revealed TTA, TTSA, and TCAA to be (88.27±1.19)°, (-0.13±1.37)°, and (2.09±5.10)° respectively, the AOFAS score was 84.3±4.2 and the VAS score was 0.7±0.5, all showing significant improvement when compared to preoperative values ( P<0.05). Conclusion: For patients with Takakura stage Ⅱ varus-type ankle arthritis, calcaneal lateral displacement osteotomy with lateral ligament repair can correct the lower limb force line, regain ankle stability, and achieving good short-term effectiveness.

Study on the structural features and geometric parameters affecting the axial mechanical properties of the primary feather rachis.

The seagull feather shaft is an important part of the feather, which provides a good mechanical support for the excellent flight performance of seagull, and has the characteristics of lightweight and high strength. In this paper, the microstructure of the seagull feather rachis was observed firstly. Then, based on the structure of feather rachis, combined with the cortex that plays the main load-bearing role, a model with the characteristics of the cortex was proposed and its finite element model was established. Through analyzing the simulation, the effect of section shape of cortex on mechanical properties of feathers under axial impact was revealed. And the conclusion that the section shape with groove structure and non-equal wall thickness could have different effects on mechanical properties was drawn. Then, parameterized cortical models were studied, including different impact velocities and different cortical heights, to reveal the differences in mechanical properties of cortical models.

Dexmedetomidine attenuates lipopolysaccharide-induced acute liver injury in rats by inhibiting caveolin-1 downstream signaling pathway.

OBJECTIVE: The aim of the present study is to investigate the anti-injury and anti-inflammatory effects of dexmedetomidine (Dex) in acute liver injury induced by lipopolysaccharide (LPS) in Sprague-Dawley rats and its possible mechanism. METHODS: The acute liver injury model of male rats was established by injecting LPS into tail vein. The mean arterial pressure (MAP) of rats was recorded at 0-7 h, and lactic acid was detected at different time points. Wet/dry weight ratio (W/D) was calculated. Pathological changes of rat liver were observed by HE staining. ALT and AST levels in serum were detected. The activities of myeloperoxidase (MPO) and superoxide dismutase (SOD) in liver tissue homogenate and the levels of IL-1ß and IL-18 in serum were detected by ELISA. Protein levels of Caveolin-1 (Cav-1), TLR-4 and NLRP3 in liver tissue were tested by immunohistochemistry method. The expression of Cav-1, TLR-4 and NLRP3 mRNA in liver tissue was detected by quantitative polymerase chain reaction (qPCR) to explore its related mechanism. RESULTS: Compared with NS group, serum lactic acid, W/D of liver tissue, MPO, SOD, IL-1ß and IL-18 were significantly increased and MAP decreased significantly in LPS group and D+L group. However, compared with NS group, D group showed no significant difference in various indicators. Compared with LPS group, MPO, SOD, IL-1ß and IL-18 were significantly decreased and MAP was significantly increased in D+L group. D+L group could significantly increase the level of Cav-1 protein and decrease the level of TLR-4 and NLRP3 protein in liver tissue caused by sepsis. The expression of Cav-1 mRNA was significantly up-regulated and the expression of TLR-4 and NLRP3 mRNA was inhibited in D+L group. CONCLUSION: Dex pretreatment protects against LPS-induced actue liver injury via inhibiting the activation of the NLRP3 signaling pathway by up-regulating the expression of Cav-1 by sepsis.

Mechanical properties and failure deformation mechanisms of yak horn under quasi-static compression and dynamic impact.

In the natural environment, the horns of yak possess remarkable structural mechanical properties to protect the head from injury. In this paper, quasi-static compression and dynamic impact tests were conducted on yak horn in different regions under axial and lateral conditions to evaluate mechanical properties such as elastic modulus, ultimate strength and energy absorption. Meanwhile, the failure deformation mechanism under both low and high strain rates is explored. Moreover, experimental analysis of the correlation among mechanical properties, sampling position, strain rate and loading direction was conducted. Fracture surface of horn was observed with the scanning electron microscope (SEM). Research data demonstrate that specific energy absorption and mechanical properties are correlated with sampling position. Under quasi-static compression and dynamic impact, clear anisotropy behavior of horn was observed, which is evidently reflected in the load-displacement curve. Mechanical properties such as elastic modulus and ultimate strength are different under quasi-static compression and dynamic impact. The failure mode of lamellar buckling and delamination existed in the axial failure process. Brittle fracture and extrusion densification occurred more frequently in the process of lateral failure.

Microstructure and compression resistance of bean goose (Anser fabalis) feather shaft.

The bean goose Anser fabalis, noted for its excellent flying ability, has feathers composed of keratinized products derived from epidermal cells, which play a crucial role in flight. The feather shaft is an important connective unit, made of a lightweight material, which also contributes to aiding flight. The shaft can withstand loads from different directions and has outstanding compression resistance. In this study, the microstructure and composition of the A. fabalis feather shaft were observed by scanning electron microscopy and Fourier transform infrared spectrometry, and its compression resistance was studied by compression testing. The results indicated that the mechanical property of the shaft is related to its microstructure. Compression testing verified that the primary feathers had the strongest mechanical properties, followed by the secondaries, and finally the alulae. Under the same conditions, the specific energy absorption of the three feather types was 5.96, 5.02, and 3.17 J/g, respectively. With increasing moisture content, the rachis was softened and the energy absorption was reduced. At low moisture content, the specific energy absorption of the primaries was reduced to 1.03 J/g, that of the secondaries was reduced to 1.72 J/g, and that of the alulae to 0.39 J/g. The feather shafts have the advantage of light weight while maintaining the required mechanical properties. These results provide a theoretical and experimental basis for crashworthiness in bionic designs based on the requirements of light weight.

Strong Acid Anions Significantly Increasing the Charge State of Proteins during Electrospray Ionization.

Regulation of protein's charge state in electrospray is of great importance to the analysis of proteins. Different methods have been developed so far to increase the charge state of proteins. In this work, we investigated the influence of different anions on the charge state of proteins. Both strong acid anions and weak acid anions were taken into consideration. The results showed that the presence of 5 mM strong acid anions in acidic solutions could significantly increase the charge state of proteins. In comparison, weak acid anions with the same concentration in solution had little impact on the charge state of proteins. The species of the cations in the samples had very limited influence on the charge state. The presence of a certain amount of acid in sample solution was critical to the effect of strong acid anions. Almost no increase of the charge state was observed when no acid was added to the samples. However, remarkable increase of the charge state of myoglobin (Mb) was observed when 0.001% (v/v) acetic acid (HAc) was added to the sample together with 5 mM sodium chloride (NaCl). A higher concentration of acid in samples would further enhance the effect of strong acid anions on the increase of the charge state. Further investigations into the mechanism revealed that the effect of the strong acid anions on the charge state of proteins was based on the unfolding of the protein molecules during electrospray ionization (ESI). The interactions among H+, anions, and protein molecules were so strong that it caused the unfolding of protein molecules and resulted in the increasing of proteins' charge states. The key factor that made strong acid anions and weak acid anions different in the results was the hydrolysis of the weak acid anions in acidic solutions. The present work furthers our understanding about electrospray, as well as the regulation of protein charge state. The presence of strong acid anions in acidic solutions can significantly influence the charge state of proteins in electrospray. Attention should be paid to this when regulating the charge state of proteins.

An engineering perspective on the microstructure and compression properties of the seagull Larus argentatus feather rachis.

The feathers of the seagull Larus argentatus are lightweight but can withstand high alternating stresses and exhibit excellent stiffness and strength. The shaft is an important part of the feather, with the functions of body protection and supporting flight. In this study, the microstructure properties of L. argentatus feather rachis were analysed by scanning electron microscopy (SEM). These analysis methods enabled the configuration, structure and compression properties of the rachis to be investigated. The results indicated that the rachis was composed of the outer cortex and the inner medulla. The cortex had a continuous layered nano-fibre composite structure, which bears, transmits, absorbs and disperses the compression force. The medulla had bubble-like cells with a porous-fibre structure, which rapidly absorbs, transmits and consumes compression force and is a suitably lightweight material for flight. Axial compression tests showed that the rachis from primary feathers had the best energy absorption and that from secondary feathers had the best compressive strength. The compressive strength might have something to do with the ratio of cortical area to medullary area. When the moisture content in the rachis increased, the compressive strength of feather rachis in different parts would decrease. These results indicate that the L. argentatus feather rachis have excellent compression resistance properties, deriving from structural factor.

A genome-wide association study of early-maturation traits in upland cotton based on the CottonSNP80K array.

Genome-wide association studies (GWASs) efficiently identify genetic loci controlling traits at a relatively high resolution. In this study, variations in major early-maturation traits, including seedling period (SP), bud period (BP), flower and boll period (FBP), and growth period (GP), of 169 upland cotton accessions were investigated, and a GWAS of early maturation was performed based on a CottonSNP80K array. A total of 49,650 high-quality single-nucleotide polymorphisms (SNPs) were screened, and 29 significant SNPs located on chromosomes A6, A7, A8, D1, D2, and D9, were repeatedly identified as associated with early-maturation traits, in at least two environments or two algorithms. Of these 29 significant SNPs, 1, 12, 11, and 5 were related to SP, BP, FBP, and GP, respectively. Six peak SNPs, TM47967, TM13732, TM20937, TM28428, TM50283, and TM72552, exhibited phenotypic contributions of approximately 10%, which could allow them to be used for marker-assisted selection. One of these, TM72552, as well as four other SNPs, TM72554, TM72555, TM72558, and TM72559, corresponded to the quantitative trait loci previously reported. In total, 274 candidate genes were identified from the genome sequences of upland cotton and were categorized based on their functional annotations. Finally, our studies identified Gh_D01G0340 and Gh_D01G0341 as potential candidate genes for improving cotton early maturity.

Bionic Design of the Bumper Beam Inspired by the Bending and Energy Absorption Characteristics of Bamboo.

This study conducted quasistatic three-point bending tests to investigate the effect of bamboo node on the energy absorption, bending, and deformation characteristics of bamboo. Results showed that the node had a reinforcing effect on the energy absorption and bending strength of the bamboo culm subjected to bending load. The experimental results demonstrated that nodal samples (NS) significantly outperform internodal samples without node (INS). Under the three-point bending load, the main failure mode of bamboo is the fracture failure. The node also showed split and fracture prevention function obviously. Based on that, a series of bionic bumper beams were designed inspired by the bamboo node. The FEM results indicated that the performance of bionic bumpers was better than that of a normal bumper with regard to bending strength, energy absorption, and being lightweight. In particular, the bionic bumper beam has the best performance with regard to bending, energy absorption, and being lightweight compared with the normal bumper under pole impact. The characteristic of the bionic bumper beam is higher than that of the normal bumper beam by 12.3% for bending strength, 36.9% for EA, and 31.4% for SEA; moreover, there was a mass reduction of 4.9%, which still needs further optimization.