Mallard hindlimbs locomotion system respond to changes in sandy ground hardness and slope.

Mallards inhabit soft grounds such as mudflats, marshes, and beaches, demonstrating remarkable proficiency in traversing these grounds. This adeptness is closely linked to the adjustments in the operation of their hindlimbs. This study employs high-speed videography to observe postural adjustments during locomotion across mudflats. Analysis of spatiotemporal parameters of the hindlimbs reveals transient and continuous changes in joints (tarsometatarso-phalangeal joint (TMTPJ), intertarsal joint (ITJ), knee, and hip) during movement on different ground hardness and slope (horizontal and uphill). The results indicate that as the stride length of the mallard increases, its speed also increases. Additionally, the stance phase duration decreases, leading to a decrease in the duty factor. Reduced ground hardness and increased slope lead to delayed adjustment of the TMTPJ, ITJ, and knee. Mallards adjust their stride length by augmenting ITJ flexion on steeper slopes, while reduced hardness prompts a decrease in TMTPJ flexion at touch-down. Additionally, the hip undergoes two brief extensions during the stance phase, indicating its crucial role in posture adjustment and propulsion on uphill grounds. Overall, the hindlimb joints of the mallard function as a whole musculoskeletal system, with each joint employing a distinct strategy for adjusting to adapt to various ground conditions.

Active Adaptive Strategies of Mallard Feet in Response to Changes in Wetness and Compactness of the Sand Terrain.

Mallards (Anas platyrhynchos) exhibit exceptional locomotive abilities in diverse terrains, such as beaches, swamps, and tidal flats. This capability is primarily attributed to their unique webbed toe structure and cooperative locomotion posture of their feet. Therefore, this study aims to further delve into the active adaptive strategies of mallard feet in response to diverse external environmental conditions. Six adult male mallards were selected for this research. Their locomotion on sandy surfaces with differing wetness levels and varying degrees of compaction were captured using a high-speed camera, and analysis of instantaneous and continuous changes in the primary joint angles of the mallards' feet, including the toe-webbed opening and closing angles, the tarsometatarsal-phalangeal joint (TMTPJ), and the intertarsal joint (ITJ). It was found that on loose sandy surfaces, increasing wetness expanded the ground contact area of the mallards' feet. This led to greater flexion at the TMTPJ joint during mid-stance, accompanied by decreased flexion of the ITJ during touch-down and mid-stance. Conversely, on compacted sand, increasing wetness resulted in a reduced foot effect area and lessened ITJ flexion at both touch-down and mid-stance. Furthermore, on looser sand, the ground contact area of the mallards' feet decreased, with an increase in ITJ buckling at touch-down. During the swing phase, sand wetness and compactness effected minimally on the feet of the mallards. On dry and loose sand ground, mallards will contract their second and fourth toes with webbing upon ground contact, covering and compacting the sand beneath while increasing ITJ flexion to mitigate sinking. This adaptation reduces the energy expended on sand and enhances body stability. In wet and compacted sand conditions, mallards expand their second and fourth toes upon ground contact and reduce ITJ flexion. Therefore, this coordinated foot and ITJ locomotion offers mallards a natural advantage when moving on various environmental media.

Biomechanical functions analysis of the Mallard webbed foot: A study of macroscopic and microscopic material assembly and tendon morphology.

The mallard webbed foot represents an exemplary model of biomechanical efficiency in avian locomotion. This study delves into the intricate material assembly and tendon morphology of the mallard webbed foot, employing both macroscopic and microscopic analyses. Through histological slices and scanning electron microscopy (SEM), we scrutinized the coupling assembly of rigid and flexible materials such as skin, tendon, and bone, while elucidating the biomechanical functions of tendons across various segments of the tarsometatarsophalangeal joint (TMTPJ). The histological examination unveiled a complex structural hierarchy extending from the external integument to the skeletal framework. Notably, the bone architecture, characterized by compact bone and honeycombed trabeculae, showcases a harmonious blend of strength and lightweight design. Tendons, traversing the phalangeal periphery, surrounded by elastic fibers, collagen fibers, and fat tissue. Fat chambers beneath the phalanx, filled with adipocytes, provide effective buffering, enabling the phalanx to withstand gravity, provide support, and facilitate locomotion. Furthermore, SEM analysis provided insights into the intricate morphology and arrangement of collagen fiber bundles within tendons. Flexor tendons in proximal and middle TMTPJ segments adopt a wavy-type, facilitating energy storage and release during weight-bearing activities. In contrast, distal TMTPJ flexor tendons assume a linear-type, emphasizing force transmission across phalangeal interfaces. Similarly, extensor tendons demonstrate segment-specific arrangements tailored to their respective biomechanical roles, with wavy-type in proximal and distal segments for energy modulation and linear-type in middle segments for enhanced force transmission and tear resistance. Overall, our findings offer a comprehensive understanding of the mallard webbed foot's biomechanical prowess, underscoring the symbiotic relationship between material composition, tendon morphology, and locomotor functionality. This study not only enriches our knowledge of avian biomechanics but also provides valuable insights for biomimetic design and tissue engineering endeavors.

From the Analysis of Anatomy and Locomotor Function of Biological Foot Systems to the Design of Bionic Foot: An Example of the Webbed Foot of the Mallard.

This study utilized the mallard's foot as the subject, examining the bone distribution via computed tomography (CT) and analyzing pertinent parameters of the tarsometatarsal bones. Additionally, gross anatomy methods were employed to elucidate the characteristics of the toes and webbing bio-structures and their material composition. Biologically, the mallard's foot comprises tarsometatarsal bones and 10 phalanges, enveloped by fascia, tendons, and skin. Vernier calipers were used to measure the bones, followed by statistical analysis to acquire structural data. Tendons, originating in proximal muscles and terminating in distal bones beneath the fascia, facilitate force transmission and systematic movement of each segment's bones. Regarding material composition, the skin layer serves both encapsulation and wrapping functions. Fat pads, located on the metatarsal side of metatarsophalangeal joints and each phalanx, function as cushioning shock absorbers. The correlation between the force applied to the tarsometatarsal bones and the webbing opening angle was explored using a texture analyzer. A simplified model describing the driving force behind the webbing opening angle was introduced. Furthermore, we designed a bionic foot, contributing a foundational reference for anti-sinking bionic foot development.

Protocol for isothermal crystallization of photovoltaic perovskite films based on volatile solvents.

The efficient functioning and stability of a perovskite photoactive layer are paramount to the performance of solar cell devices. Here, we present a protocol for the synthesis of a high-performance exemplified methylammonium lead iodide (CH3NH3PbI3 or MAPbI3) perovskite photoactive layer. We describe steps for preparing the requisite ratios of the precursor powders, synthesizing MAPbI3 single crystals, and selecting a suitable preparation technique. We then detail a flexible doping strategy for the perovskite photoactive layer. For complete details on the use and execution of this protocol, please refer to Wang and Wu (2020, 2022, 2023).1,2,3.

Tooth autotransplantation gives teeth a second chance at life: A case series.

Traditional transplantation, surgical extrusion and intentional replantation procedures are important treatment options that clinicians may consider performing in their daily clinical practice. There should be a well-constructed treatment plan for teeth with problems. In this paper, we present a series of case reports on three treatment methods used in autologous tooth transplantation and a literature review on the prevention of postoperative complications and the advantages of autologous tooth transplantation compared to dental implantation. The purpose of this study was to improve the understanding of autologous tooth transplantation.

Evaluation of staff satisfaction after the implementation of a daily goals sheet in the routine work of an oral outpatient department and its influence on work efficiency.

BACKGROUND: In March 2021, the supervision group of our hospital inspected the daily work of the outpatient department in the branch and found many problems in the process, such as an excessive number of daily check-up forms, nurses' confusion regarding the daily check-up process, and the omission of daily check-up items. Therefore, focusing on these problem, our hospital established a quality improvement team to conduct a status survey and perform this study. This study evaluated the feasibility, availability and sustainability of using a daily goals sheet in the routine work of a stomatological outpatient department and investigated the satisfaction of the nursing staff with the sheet. METHODS: After determining the theme of this study through the status survey, 60 nurses were randomly selected and divided into an experimental group and a control group by a random grouping method. Then, the study was divided into two stages: Applying the PDCA cycle method and following the MECE (Mad Exclusive, Collectively Exhaustive) principle to design, manufacture and apply the daily goals sheet. After the expert group performed Stage one, an analysis of work efficiency and routine omissions and a staff satisfaction survey were carried out. The results of the groups either using the daily goals sheet (n = 30) or not (n = 30) were analysed and compared. RESULTS: The average work time of the daily goals sheet group was 15.20 ± 1.70 min, and that of the nondaily goals sheet group was 25.30 ± 2.70 min (P < 0.001). The omission rate was 0% in the daily goals sheet group and 16.67% in the nondaily goals sheet group. Staff satisfaction with the use of the daily goals sheet was high. CONCLUSION: The daily goals sheet can make routine work more efficient and convenient in a stomatological outpatient department. It is recommended for use in stomatological outpatient departments or hospitals.

Pilot study of minimum occlusive force of vascular clamps on arterial vessels in rats.

Our aims were to determine the accuracy of an improved formula for determining the minimum occlusive force (MOF) of a vascular clamp on rats' abdominal aortas, compare our findings with the calculated theoretical MOF, and provide reference data for clinical research and development of medical instruments that cause minimal damage. We created a vessel closure model and developed a formula for calculating the theoretical MOF of arterial vessels when they are occluded. This formula utilises the blood pressure in the blood vessel, its diameter, and the width of the vascular clamp. We then measured the actual MOF in 24 rat abdominal aortic segments with different diameters and different blood pressures and compared the theoretical and actual MOFs. Analysis of the experimental data showed a probability of 0.315, which means that, under the condition of normal distribution, the difference between the theoretical and actual MOF is not significant at the α = 0.05 level. Thus, the actual measured MOF tended to be consistent with the theoretical MOF calculated by the formula we developed. The improved formula will provide a reference for clinical research and development of medical instruments that cause minimal injury, thus contributing to the development of microsurgery.

[Left mandibular infantile myofibromatosis: a case report].

Infantile myofibromatosis is a rare benign childhood myofibroblastoma. A case of infantile myofibromatosis of the left mandible was reported, and relevant literature was reviewed to discuss the clinical characteristics, pathogenesis, imaging characteristics, pathological characteristics, differential diagnosis, and the treatment of the tumor to improve the understanding of the tumor.

New progress in the clinical application of GBR membrane materials / 口腔疾病防治

@#Guided bone regeneration (GBR) barrier membranes are of great significance for the reconstruction of the health and function of different periodontal tissues. Biocompatibility, spatial maintenance, closure, controllability and biological activation are the main criteria that should be met by these membranes. Artificial barrier membrane biomaterials can be divided into synthetic polymer materials, natural polymer materials and metals. According to their degradation characteristics, these membranes can be divided into two categories, absorbable and nonabsorbable membranes. GBR used for horizontal bone increments can be used to treat various types of bone defects, including the treatment of bone fenestration and bone cracking. The use of a non-absorbable e-PTFE membrane or absorbable collagen membrane can achieve the expected effect. However, for incremental or vertical bone growth at the alveolar crest, the use of this membrane is very challenging and requires good strength to maintain the osteogenic space. This space can be enhanced with e-PTFE or d-PTFE membranes with stable morphology, or absorbable membranes can be covered with titanium plates or meshes to achieve vertical bone increments. Currently, bioactive membranes, digital 3D-printed titanium membranes and piezoelectric active biological membranes are research hotspots. In future research, the biological activation of these membranes will be further improved, which will promote the development of artificial membranes in the next stage.