Temperature-Responsive, Femtosecond Laser-Ablated Ceramic Surfaces with Switchable Wettability for On-Demand Droplet Transfer.

Reversible wettability transition has drawn substantial interest because of its importance for widespread applications, but facile realization of such transition on ceramic surfaces, which is promising for achieving on-demand droplet manipulation under harsh conditions, remains rare. Herein, superhydrophobic zirconia ceramic surfaces that can reversibly and repeatedly transit between superhydrophobicity and superhydrophilicity after alternate heating treatments have been fabricated using a femtosecond laser. The underlying mechanisms of the complex wettability transitions on the laser-ablated zirconia surfaces are elucidated.

Calcium release-mediated adsorption and lubrication of salivary proteins on resin-based dental composites.

The lack of wear resistance is always a challenge for clinical applications of resin-based dental composites (RBDCs). In this study, the role of the calcium release from RBDCs in the adsorption and lubrication of salivary proteins was investigated, aiming to provide useful insights concerning the development of high-performance RBDCs. Three experimental RBDCs with distinct calcium-releasing capabilities were prepared using calcium phosphate particles as inorganic fillers.

A Method of Calibration for the Distortion of LiDAR Integrating IMU and Odometer.

To improve the motion distortion caused by LiDAR data at low and medium frame rates when moving, this paper proposes an improved algorithm for scanning matching of estimated velocity that combines an IMU and odometer. First, the information of the IMU and the odometer is fused, and the pose of the LiDAR is obtained using the linear interpolation method. The ICP method is used to scan and match the LiDAR data.

Heterogeneous hardening of enamel surface by occlusal loading: Effect of nanofiber orientation.

Human tooth enamel is composed of enamel rods and surrounding inter-rod enamel. As the fundamental block of enamel, hydroxyapatite (HAP) nanofibers are mostly longitudinally aligned in the rods but inclined in the inter-rod enamel. The surface hardening of enamel by occlusal loading is reportedly a result of hydroxyapatite nanofiber fragmentation and rearrangement and plays an important role in the anti-wear performance of enamel, but little is known about the effect of HAP nanofiber orientation on enamel surface hardening.

Surface Hardening Behavior of Enamel by Masticatory Loading: Occurrence Mechanism and Antiwear Effect.

Previous studies have suggested that surface hardening occurs in human tooth enamel under certain loading conditions. However, the occurrence mechanism and significance remain unclear. In this study, the surface hardening behavior of enamel under masticatory loading was studied in vitro using impact treatment and the nanoindentation/scratch technique to identify the mechanism and antiwear effect.

Wear mechanism of human tooth enamel: The role of interfacial protein bonding between HA crystals.

Human tooth enamel, the most mineralized tissue in body, contains less than 2 wt% protein. Consequently, the importance of the protein to enamel mechanical response has always been overlooked. In this study, the role of minor protein in providing enamel microstructure and mechanical performance, especially tribological properties, were studied using deproteinization treatment and nano-indentation/scratch technique.

Patient-specific finite element analysis of frictional behavior in different esophageal regions during endoscopy.

Purpose: Endoscopy is a common and effective method to treat digestive system diseases. Not only can it detect the physiological state of the digestive tract, but also can conduct clinical operations. As a result, it's of great significance to make clear the relationship between the clinical operation and the complications.

Modeling the initial-volume dependent approximate compressibility of porcine liver tissues using a novel volumetric strain energy model.

Experimental observations in the open literature indicate that soft tissues are slightly compressible, and this characteristic affects not only their overall elastic response but also their damage evolution and failure mechanism. In this study, we find that the compressibility of liver tissues is also closely related to the initial specimen volume according to the confined compression tests: the samples with smaller initial volume exhibit more compressible behavior compared to the larger ones. To include this initial-volume dependent effect, we developed a novel volumetric strain energy model with two variables, i.

Influence of clamping parameters on the trauma of rabbit small intestine tissue.

Background: During clamping operation for minimally invasive intestinal surgery, patients often suffer from small intestine trauma. This phenomenon will lead to various complications, increase recovery time and cause pain for patients.

Methods: In this paper, preliminary simulations of small intestine clamping operations in the minimally invasive surgery were made by conducting compression tests under different clamping stresses, durations and loading rates.

Effect of calcium ions on the adsorption and lubrication behavior of salivary proteins on human tooth enamel surface.

The aim of this study is to investigate the effect of calcium ions on the adsorption and lubrication behavior of salivary proteins on human tooth enamel. Human whole saliva was collected from healthy donors. Three testing groups were calcium ion-enhanced saliva samples with an increased ion concentration of 1 mmol/L, 5 mmol/L, and 10 mmol/L, respectively.

[Study on the mechanical properties of sutures in the process of suturing].

Suture broken, knot slipping and tissue tearing are the main reasons of wound closure failure in clinical operation. Based on this, we simulated the suturing and healing operation by using a biological materials testing machine and investigated the tensile properties before and after knotting, relaxation property and friction property of three common sutures: silk, polyglactin 910 and polypropylene. Results show that the tensile property decreased after knotting.

Load distribution measurement instrument for oscillating follower cam mechanism.

Cam mechanism is widely applied in industry because it can help achieve various complex motions of the follower via the cam contour design. However, its performance is significantly affected by the wear condition. This study proposes a load distribution measurement instrument to assist the study on friction and wear regularities of oscillating follower cam mechanisms through obtaining the normal pressure (F) and friction force (F) distributions along the cam profile.

Correction to: 'Comment on van Casteren (2018): softer metallic spheres do abrade harder enamel'.

[This corrects the article DOI: 10.1098/rsos.181376.

Research of the role of microstructure in the wear mechanism of canine and bovine enamel.

The relationship between the microstructure and tribological behavior of mammalian tooth enamel has not been fully understood. In this paper, the microstructure, mechanical properties, and tribological behavior of canine (carnivore) and bovine (herbivore) enamel are studied using scanning electronic microscopy and nano-indentation/scratch technique, aiming to reveal the contribution of enamel microstructure to its mechanical and tribological properties. Canine enamel has a microstructure of hard keyhole-like rods embedded in soft inter-rod enamel, and its surface exhibits high resistance against both micro-crack initiation and crack-induced delamination during friction and wear process.

Effect of high-frequency electric field on the tissue sticking of minimally invasive electrosurgical devices.

Generally minimally invasive surgery is performed using an endoscope and other instruments including electrosurgical units (ESUs), and the adhesion of tissue to electrodes is a major concern. The mechanism governing this tissue sticking, especially the influence of high-frequency electric field, is still unclear. In this study, the effect of high-frequency electric field on the tissue sticking upon electrodes was investigated.

Water-Switchable Interfacial Bonding on Tooth Enamel Surface.

Tooth enamel is a distinctive nanocomposite with a highly organized hierarchical structure made of nanometer- and micrometer-scale building blocks. This structure has an excellent mechanical function that can last for decades thanks to an effective but underexploited interfacial chemical bonding between the building blocks. In this study, the nanomechanical system test (NST), scanning electron microscope (SEM), X-ray diffraction (XRD, including powder XRD or PXRD, small angle XRD or SAXRD, and grazing incidence small angle XRD or GISAXRD), and atomic force microscope (AFM) have been employed to analyze the water-mediated bonding on the enamel surface.

[Security research of laparoscopic graspers during tissue clamping operation].

The large force applied by laparoscopic grasper during clamping operation can cause tissue damage and induce various complications. In this research, the security of graspers with different radii of curvature and teeth were evaluated by using experimental investigation, finite element simulation and tissue damage assessment method based on compression tests with rabbit large intestines models. Results showed that the most serious tissue damages appeared in areas that were in contact with the jaw edges, which were the regions of stress concentration.

Enamel crystallite strength and wear: nanoscale responses of teeth to chewing loads.

The nanoscale responses of teeth to chewing loads are poorly understood. This has contributed to debate concerning the aetiology of enamel wear and resistance to fracture. Here we develop a new model for reactions of individual hydroxyapatite nanofibres to varying loads and directions of force.

Effect of alcohol stimulation on salivary pellicle formation on human tooth enamel surface and its lubricating performance.

This study was to investigate the salivary pellicle formation on the surface of human tooth enamel and its lubricating behavior under alcohol stimulation. Normal saliva and alcohol-stimulated saliva were collected from a young male volunteer after rinsing mouth with deionized water and different-concentration alcohol aqueous solution, respectively. Saliva-adsorption treatment was conducted in vitro on enamel surface to obtain salivary pellicle.

Influence of clamping stress and duration on the trauma of liver tissue during surgery operation.

Background: Tissue grasping damage often occurs in minimally invasive surgery, which would increase the postoperative recovery time and the risk of surgical complications. The purpose of this study was to evaluate the relationship between liver tissue trauma and compression stress magnitude and duration during tissue clamping operation.

Methods: The clamping experiments of liver tissues in vivo were conducted by using a universal soft tissue mechanical testing machine under different clamping stress magnitudes and durations.

Impact wear behavior of human tooth enamel under simulated chewing conditions.

Previous studies mostly focused on the sliding wear behavior of human teeth, and little effort has been made so far to study the impact wear of human teeth. The objective of this study was to investigate the impact wear process and mechanism of human tooth enamel and the influence of water content within enamel. In this paper, the impact wear behaviors of fresh and dried human tooth enamel against SiC ceramic have been investigated using a specially designed impact test machine.

Technical note: An in vitro study of dental microwear formation using the BITE Master II chewing machine.

Dental microwear has been used for decades to reconstruct the diets of fossil hominins and bioarchaeological populations. The basic theory has been that hard-brittle foods (e.g.

New model to explain tooth wear with implications for microwear formation and diet reconstruction.

Paleoanthropologists and vertebrate paleontologists have for decades debated the etiology of tooth wear and its implications for understanding the diets of human ancestors and other extinct mammals. The debate has recently taken a twist, calling into question the efficacy of dental microwear to reveal diet. Some argue that endogenous abrasives in plants (opal phytoliths) are too soft to abrade enamel, and that tooth wear is caused principally by exogenous quartz grit on food.

Fabrication mechanism of friction-induced selective etching on Si(100) surface.

As a maskless nanofabrication technique, friction-induced selective etching can easily produce nanopatterns on a Si(100) surface. Experimental results indicated that the height of the nanopatterns increased with the KOH etching time, while their width increased with the scratching load. It has also found that a contact pressure of 6.