Effects of dissolved oxygen changes in the benthic environment on phosphorus flux at the sediment-water interface in a coastal brackish lake.

In semi-enclosed coastal brackish lakes, changes in dissolved oxygen in the bottom layer due to salinity stratification can affect the flux of phosphorus (P) at the sediment-water interface, resulting in short- and long-term water quality fluctuations in the water column. In this study, the physicochemical properties of the water layers and sediments at five sites in Saemangeum Lake were analyzed in spring and autumn for four years, and phosphorus release experiments from sediments were conducted for 20 days under oxic and anoxic conditions during the same period. Sediment total phosphorus (T-P) decreased in autumn compared to spring due to mineralization of organic bound phosphorus, which was the most dominant P fraction.

Injuries and Illness during the 2019 Gwangju FINA and Masters World Championships in Elite and Amateur Athletes.

Comparative analysis of injury and illness prevalence in elite and amateur athletes provides the basis for the development of tailored prevention programs. The authors analyzed the differences in frequency and characteristics of injuries and illnesses which occurred in elite and amateur athletes during the 2019 Gwangju Federation Internationale de Natation (FINA) and Masters World Championships. The 2019 FINA World Championships hosted 3095 athletes in the disciplines of swimming, diving, high diving, artistic swimming, water polo, and open water swimming.

Characterization of Non-Invasively Induced Post-Traumatic Osteoarthritis in Mice.

The pathophysiology of post-traumatic arthritis (PTOA) is not fully understood. This study used non-invasive repetitive mechanical loading (ML) mouse models to study biochemical, biomechanical, and pain-related behavioral changes induced in mice. Mouse models reflected the effects of the early stages of PTOA in humans.

Osseointegration of 3D-printed titanium implants with surface and structure modifications.

Background: The purpose of this study was to establish a mechanical and histological basis for the development of biocompatible maxillofacial reconstruction implants by combining 3D-printed porous titanium structures and surface treatment. Improved osseointegration of 3D-printed titanium implants for reconstruction of maxillofacial segmental bone defect could be advantageous in not only quick osseointegration into the bone tissue but also in stabilizing the reconstruction.

Methods: Various macro-mesh titanium scaffolds were fabricated by 3D-printing.

Biomechanical Efficacy and Effectiveness of Orthodontic Treatment with Transparent Aligners in Mild Crowding Dentition-A Finite Element Analysis.

Orthodontic treatment increasingly involves transparent aligners; however, biomechanical analysis of their treatment effects under clinical conditions is lacking. We compared the biomechanical efficacy and effectiveness of orthodontic treatment with transparent aligners and of fixed appliances in simulated clinical orthodontic treatment conditions using orthodontic finite element (FE) models. In the FE analysis, we used Model Activation/De-Activation analysis to validate our method.

3D-printed, bioactive ceramic scaffold with rhBMP-2 in treating critical femoral bone defects in rabbits using the induced membrane technique.

Although autogenous bone grafts are an optimal filling material for the induced membrane technique, limited availability and complications at the harvest site have created a need for alternative graft materials. We aimed to investigate the effect of an rhBMP-2-coated, 3D-printed, macro/microporous CaO-SiO -P O -B O bioactive ceramic scaffold in the treatment of critical femoral bone defects in rabbits using the induced membrane technique. A 15-mm segmental bone defect was made in the metadiaphyseal area of the distal femur of 14 rabbits.

Comparative Analysis of Stress in the Periodontal Ligament and Center of Rotation in the Tooth after Orthodontic Treatment Depending on Clear Aligner Thickness-Finite Element Analysis Study.

Lately, in orthodontic treatments, the use of transparent aligners for the correction of malocclusions has become prominent owing to their intrinsic advantages such as esthetics, comfort, and minimal maintenance. Attempts at improving upon this technology by varying various parameters to investigate the effects on treatments have been carried out by several researchers. Here, we aimed to investigate the biomechanical and clinical effects of aligner thickness on stress distributions in the periodontal ligament and changes in the tooth's center of rotation.

Modeling behaviors of permeable non-spherical micro-plastic aggregates by aggregation/sedimentation in turbulent freshwater flow.

This study developed and evaluated a behavior model for permeable non-spherical micro-plastic aggregates in a turbulent flow of freshwater based on fractal theory, as conducting experimental and modeling studies. Laboratory-scale experiments evaluated attachment efficiency α to aggregation kinetics in an aquatic environment (pH 6, 20 ℃) of the electrolyte (Al). The experimental α was dependent on characteristics of plastics (type, size, and density) and ranged from 0.

Mechanical Assessment of Fatigue Characteristics between Single- and Multi-Directional Cyclic Loading Modes on a Dental Implant System.

Mechanical testing based on ISO 14801 standard is generally used to evaluate the performance of the dental implant system according to material and design changes. However, the test method is difficult to reflect on the clinical environment because the ISO 14801 standard does not take into account the various loads from different directions during chewing motion. In addition, the fracture pattern of the implant system can occur both in the horizontal and the vertical directions.

Successful extracorporeal life support in respiratory failure after copper sulphate ingestion.

A 44-year-old woman intentionally ingested a solution of copper sulphate. She had minimal intravascular haemolysis and methemoglobinaemia but developed acute respiratory distress syndrome (ARDS) 4 hours after acute copper sulphate poisoning. This required extracorporeal membrane oxygenation (ECMO) management in the intensive care unit.

Effect of guided bone regeneration on bone quality surrounding dental implants.

Bone quality as well as its quantity at the implant interface is responsible for determining stability of the implant system. The objective of this study is to examine the nanoindentation based elastic modulus (E) at different bone regions adjacent to titanium dental implants with guided bone regeneration (GBR) treated with DBM and BMP-2 during different post-implantation periods. Six adult male beagle dogs were used to create circumferential defects with buccal bone removal at each implantation site of mandibles.

Relationships of bone characteristics in MYO9B deficient femurs.

The objective of this study was to examine relationships among a variety of bone characteristics, including volumetric, mineral density, geometric, dynamic mechanical analysis, and static fracture mechanical properties. As MYO9B is an unconventional myosin in bone cells responsible for normal skeletal growth, bone characteristics of wild-type (WT), heterozygous (HET), and MYO9B knockout (KO) mice groups were compared as an animal model to express different bone quantity and quality. Forty-five sex-matched 12-week-old mice were used in this study.

Phenomena of Nano- and Micro-Pore Formation on Ti-(10~50)Ta Alloys by Plasma Electrolytic Oxidation for Dental Implants.

In this study, the phenomena of nano and micro-pore formation on Ti-(10~50)Ta alloys by plasma electrolytic oxidation for dental implants was investigated using various experimental techniques. The Ti–xTa alloys having Ta contents of 10, 30, and 50 wt.% were prepared using arc-melting vacuum furnace.

Immediate mechanical stability of threaded and porous implant systems.

Background: Primary stability of a dental implant system is an essential factor to maintain its long-term success. Thus, the objective of this study was to examine whether primary stability is different between threaded and porous dental implant systems placed in artificial bone blocks and human cadaveric mandibular bone.

Materials And Methods: Forty-two threaded and 42 highly porous dental implants were placed in artificial polyurethane bone foams with 7 different thicknesses (3.

The RhoGAP Myo9b Promotes Bone Growth by Mediating Osteoblastic Responsiveness to IGF-1.

The Ras homolog A (RhoA) subfamily of Rho guanosine triphosphatases (GTPases) regulates actin-based cellular functions in bone such as differentiation, migration, and mechanotransduction. Polymorphisms or genetic ablation of RHOA and some of its regulatory guanine exchange factors (GEFs) have been linked to poor bone health in humans and mice, but the effects of RhoA-specific GTPase-activating proteins (GAPs) on bone quality have not yet been identified. Therefore, we examined the consequences of RhoGAP Myo9b gene knockout on bone growth, phenotype, and cellular activity.

Primary stability and viscoelastic displacement of mini-implant system under loading.

Background: The objectives of the current study were to examine the effects of mini-implant diameters on 1) primary stability before bone properties are changed by active peri-implant bone remodeling and 2) the time-dependent displacement of mini-implant systems in bone under a functional radial loading and their associations with bone mineral density.

Methods: Twenty one, 8mm length mini-implants (7 each for 1.4mm, 1.

Mechanical properties of bone tissues surrounding dental implant systems with different treatments and healing periods.

Objectives: The objective of the current study was to examine whether the nanoindentation parameters can assess the alteration of bone quality resulting from different degrees of bone remodeling between bone tissue ages around the dental implant interface with different treatments and healing periods.

Materials And Methods: Dental implants were placed in mandibles of six male dogs. Treatment groups included: resorbable blast media-treated titanium (Ti) implants, alumina-blasted zirconia implants (ATZ), alumina-blasted zirconia implants applied with demineralized bone matrix (ATZ-D), and alumina-blasted zirconia implants applied with rhBMP-2 (ATZ-B).

Biomimetic whitlockite inorganic nanoparticles-mediated in situ remodeling and rapid bone regeneration.

Bone remodeling process relies on complex signaling pathway between osteoblasts and osteoclasts and control mechanisms to achieve homeostasis of their growth and differentiation. Despite previous achievements in understanding complicated signaling pathways between cells and bone extracellular matrices during bone remodeling process, a role of local ionic concentration remains to be elucidated. Here, we demonstrate that synthetic whitlockite (WH: CaMg(HPO)(PO)) nanoparticles can recapitulate early-stage of bone regeneration through stimulating osteogenic differentiation, prohibiting osteoclastic activity, and transforming into mechanically enhanced hydroxyapatite (HAP)-neo bone tissues by continuous supply of PO and Mg under physiological conditions.

Surface Characteristics of Nano-Structured Silicon/Hydroxyapatite Deposition onto the Ti-Nb-Zr Alloy.

The Ti-Nb-Zr alloy was manufactured with 35 wt% of Nb and 10 wt% of Zr by arc melting furnace to be a beta phase. Electrochemical deposition of Si substituted Ca/P was performed by pulsing the potential with a method of cyclic voltammetry, and changed cyclic time between 10, 30, 70, and 150. The electrolyte was prepared by dissolving the reagent-grade chemicals: Ca(NO3)2, NH4H2PO4, and Na2SiO3 x 9H20 to be 1.

Micro-Computed Tomography of Tooth Volume Changes Following Post Removal.

Purpose: To measure tooth volume change before and after post removal using micro-CT and to compare the difference among various combinations of prefabricated post and cement systems.

Materials And Methods: Forty-eight extracted maxillary anterior teeth and mandibular canines were sectioned 13 mm from the apex. Root canals were properly instrumented.

Differences between buccal and lingual bone quality and quantity of peri-implant regions.

The objective of the current study was to examine whether peri-implant bone tissue properties are different between the buccal and lingual regions treated by growth factors. Four dental implant groups were used: titanium (Ti) implants, alumina-blasted zirconia implants (ATZ-N), alumina-blasted zirconia implants with demineralized bone matrix (DBM) (ATZ-D), and alumina-blasted zirconia implants with rhBMP-2 (ATZ-B). These implants were placed in mandibles of six male dogs.

Electrochemical Deposition of Si-Ca/P on Nanotube Formed Beta Ti Alloy by Cyclic Voltammetry Method.

The purpose of this study was to investigate electrochemical deposition of Si-Ca/P on nanotube formed Ti-35Nb-10Zr alloy by cyclic voltammetry method. Electrochemical deposition of Si substituted Ca/P was performed by pulsing the applied potential on nanotube formed surface. The surface characteristics were observed by field-emission scanning electron microscopy, X-ray diffractometer, and potentiodynamic polarization test.

Nanotubular Structure on the Ti-29Nb-5Zr Alloy by Scanning Transmission Electron Microscope.

In this study, we reported the observation of highly ordered nanotubular structure on the Ti-29Nb-5Zr alloy in various potentials and electrolytes by field emission scanning electron microscopy and scanning transmission electron microscope. From the X-ray diffraction results and microstructure analysis, Ti-29Nb-5Zr alloy had β phase. The nanotube morphologies of Ti-29Nb-5Zr alloy were transformed from nano-porous structure to nanotube structure as NaF concentration and voltage increased.

Nanotube Nucleation Phenomena of Titanium Dioxide on the Ti-6Al-4V Alloy Using Anodic Titanium Oxide Technique.

The purpose of this study was to investigate nanotube nucleation phenomena of titanium dioxide on the Ti-6Al-4V alloy were investigated using anodic titanium oxide technique. Heat treatment was performed at 1000 degrees C for 12 hour for formation of α+/β phase and water quenched. Ti-6Al-4V alloy was anodized in 1 M H3PO4 electrolytes containing 0.