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Biomimetics (Basel, Switzerland) May 2024The propulsion system is the core component of unmanned underwater vehicles. The flapping propulsion method of marine animals' flippers, which allows for flexibility,...
The propulsion system is the core component of unmanned underwater vehicles. The flapping propulsion method of marine animals' flippers, which allows for flexibility, low noise, and high energy utilization at low speeds, can provide a new perspective for the development of new propulsion technology. In this study, a new experimental flapping propulsion apparatus that can be installed in both directions has been constructed. The guide rail slider mechanism can achieve the retention of force in the direction of movement, thereby decoupling thrust, lift, and torque. Subsequently, the motion parameters of frequency-amplitude related to the thrust and lift of a bionic flapping-foil are scrutinized. A response surface connecting propulsion efficiency and these motion parameters is formulated. The highest efficiency of the flapping-foil propulsion is achieved at a frequency of 2 Hz and an amplitude of 40°. Furthermore, the impact of the installation mode and the aspect ratio of the flapping-foil is examined. The reverse installation of the swing yields a higher thrust than the forward swing. As the chord length remains constant and the span length increases, the propulsive efficiency gradually improves. When the chord length is extended to a certain degree, the propulsion efficiency exhibits a parabolic pattern, increasing initially and then diminishing. This investigation offers a novel perspective for the bionic design within the domain of underwater propulsion. This research provides valuable theoretical guidance for bionic design in the underwater propulsion field.
PubMed: 38921204
DOI: 10.3390/biomimetics9060324 -
BioRxiv : the Preprint Server For... Jun 2024A. Numerous studies have been trying to create nanomaterials based antimicrobial surfaces to combat the growing bacterial infection problems. Mechanical durability has...
A. Numerous studies have been trying to create nanomaterials based antimicrobial surfaces to combat the growing bacterial infection problems. Mechanical durability has become one of the major challenges to applying those surfaces in real life. In this study, we demonstrate the Durable Antimicrobial Microstructures Surface (DAMS) consisting of DLP 3D printed microstructures and zinc oxide (ZnO) nanoflowers. The microstructures serve as a protection armor for the nanoflowers during abrasion. The antimicrobial ability was tested by immersing in 2E8 CFU/mL ( ) suspension and then evaluated using electron microscopy. Compared to the bare control, our results show that the DAMS reduces bacterial coverage by more than 90% after 12 hrs of incubation and approximately 50% after 48 hrs of incubation before abrasion. Importantly, bacterial coverage is reduced by approximately 50% after 2 min of abrasion with a tribometer, and DAMS remains effective even after 6 min of abrasion. These findings highlight the potential of DAMS as an affordable, scalable, and durable antimicrobial surface for various biomedical applications.
PubMed: 38915492
DOI: 10.1101/2024.06.11.598554 -
Heliyon Jun 2024This study aims to prevent ice accumulation on the surface of drilling tools by investigating the effectiveness of hydrophobic coatings, which is one of the most...
This study aims to prevent ice accumulation on the surface of drilling tools by investigating the effectiveness of hydrophobic coatings, which is one of the most promising methods to solve drilling difficulties in warm ice. Herein, four types of hydrophobic organic coatings that can be used on metal surfaces were tested to evaluate their anti-icing performance, service durability, and friction properties. All of them possess rough surfaces with microstructure characteristics such as pores, stripes, or micropapillae. They also exhibit hydrophobicity, with water contact angles of 101.6°, 100.0°, 103.1°, and 108.5°. They can significantly prolong the required freezing time of water droplets on their surfaces, effectively reduce ice adhesion, and decrease the friction between ice and their surface. The ice adhesion in the axial, tensile, and tangential directions can be reduced by 65.64 %, 56.31 %, and 72.11 %, respectively, for the coating with silicon (Si)-based and fluorine (F)-containin compounds (coating-) at -30 °C; while it can be reduced by 85.05 %, 73.9 %, and 94.2 %, respectively, for the coatings with Si-based and polytetrafluoroethylene (PTFE) compounds (coating-). The two coatings mentioned above lose their anti-icing performance after 20 icing and de-icing cycles, and their hydrophobicity after 120 abrasion cycles under a load of 6 N.
PubMed: 38912511
DOI: 10.1016/j.heliyon.2024.e32319 -
Orthopaedic Journal of Sports Medicine Jun 2024While prevention protocols have been implemented, skiing-related musculoskeletal injuries and concussions continue to present to emergency departments in the United...
BACKGROUND
While prevention protocols have been implemented, skiing-related musculoskeletal injuries and concussions continue to present to emergency departments in the United States. Previous literature has suggested the pediatric population may constitute up to 40% of skiing-related injuries.
PURPOSE
To assess injury trends and the underlying mechanisms of skiing injuries in pediatric patients seen at emergency departments in the United States.
STUDY DESIGN
Descriptive epidemiology study.
METHODS
The National Electronic Injury Surveillance System (NEISS) was queried for pediatric (age ≤18 years) skiing injuries between January 1, 2012, and December 31, 2022. Injury mechanism, location, disposition, and diagnosis were recorded, and the statistical sample weight assigned by NEISS by hospital was used to calculate national estimates (NEs). Injury trends were evaluated with linear regression analysis.
RESULTS
Overall, 2951 pediatric skiing injuries were included (NE = 123,386). The mean age of the patients was 12.4 ± 3.5 years, with 61.3% of the injuries occurring in male patients. Impact with the ground was the most common injury mechanism (NE = 87,407; 70.8%). Fractures were the most common diagnosis (NE = 38,527, 31.2%), followed by strains/sprains (NE = 22,562, 18.3%), contusions/abrasions (NE = 16,257, 13.2%), and concussions (NE = 12,449, 10.1%). The lower leg was the most common fracture site (NE = 9509, 24.7%), followed by the shoulder (NE = 7131, 18.5%) and lower arm (NE = 5876, 15.3%). Analysis of annual injuries revealed no significant trend between 2012 and 2022 ( = .17), with fluctuations apparent throughout the study period. Significant decreases were seen in strains/sprains ( < .01) and contusions/abrasions ( < .01), but not in concussions ( = .57) or fractures ( = .70).
CONCLUSION
Impacts with the snow/ground made up 70.8% of all injuries. Fractures were the most common injury diagnosis, followed by strains/sprains, with the lower leg being most frequently fractured. While strains/sprains and contusions/abrasions showed a significant decline, there were no significant trends in fractures and concussions between 2012 and 2022.
PubMed: 38911123
DOI: 10.1177/23259671241255704 -
Environmental Research Jun 2024Heavy metal pollution in water sources has become a major worldwide environmental issue, posing a threat to aquatic ecosystems and human health. The pollution of the... (Review)
Review
Heavy metal pollution in water sources has become a major worldwide environmental issue, posing a threat to aquatic ecosystems and human health. The pollution of the aquatic environment is increasing as a result of industrialization, climate change, and urban development. The sources of heavy metal pollution in water include mining waste, leachates from landfills, municipal and industrial wastewater, urban runoff, and natural events such as volcanism, weathering, and rock abrasion. Heavy metal ions are toxic and potentially carcinogenic. They can also buildup in biological systems and cause bioaccumulation even at low levels of exposure, heavy metals can cause harm to organs such as the nervous system, liver and lungs, kidneys and stomach, skin, and reproductive systems. There were various approaches tried to purify water and maintain water quality. The main purpose of this article was to investigate the occurrence and fate of the dangerous contaminants (Heavy metal and metalloids) found in domestic and industrial effluents. This effluent mixes with other water streams and is used for agricultural activities and other domestic activities further complicating the issue. It also discussed conventional and non-conventional treatment methods for heavy metals from aquatic environments. Conclusively, a pollution assessment of heavy metals and a human health risk assessment of heavy metals in water resources have been explained. In addition, there have been efforts to focus on heavy metal sequestration from industrial waste streams and to create a scientific framework for reducing heavy metal discharges into the aquatic environment.
PubMed: 38906448
DOI: 10.1016/j.envres.2024.119440 -
Interactive Journal of Medical Research Jun 2024Spontaneous pneumothorax is one of the most common conditions encountered in thoracic surgery. This condition can be treated conservatively or surgically based on...
Spontaneous pneumothorax is one of the most common conditions encountered in thoracic surgery. This condition can be treated conservatively or surgically based on indications and guidelines. Traditional surgical management includes pleurodesis (mechanical or chemical) in addition to bullectomy if the bullae can be identified. Mechanical pleurodesis is usually performed by surgical pleurectomy or pleural abrasion. In this case report, we present a case of a young patient with spontaneous pneumothorax who needed a surgical intervention. We performed a new, innovative surgical technique for surgical pleurectomy where we used carbon dioxide for dissection of the parietal pleura (capnodissection). This technique may provide similar efficiency to the traditional procedure but with less risk of bleeding and complications.
PubMed: 38905630
DOI: 10.2196/54497 -
General Dentistry 2024The purpose of this study was to determine the most effective method for bonding composite resin to artificially aged amalgam. A spherical amalgam alloy was triturated...
The purpose of this study was to determine the most effective method for bonding composite resin to artificially aged amalgam. A spherical amalgam alloy was triturated and condensed by hand into cylindrical plastic molds (6 mm in diameter and 4 mm in height) to create 90 specimens, which were then aged for 2 weeks in closed plastic containers at 23°C. The amalgam surfaces underwent 1 of 3 surface treatments (n = 30 per treatment): (1) air particle abrasion (APA) with 50-μm aluminum oxide particles applied with a force of 45 psi from a 10-mm distance, followed by rinsing with deionized water for 60 seconds; (2) APA following the same protocol with subsequent application of a metal primer (Alloy Primer); or (3) coating with 30-μm silica (CoJet) at a force of 45 psi from a 10-mm distance until the surface turned black. Specimens were then treated with 1 of 3 adhesives (n = 10 per adhesive per surface treatment): (1) 2-step total-etch adhesive (OptiBond Solo Plus), (2) 1-step self-etching adhesive (Scotchbond Universal), or (3) dual-cured resin cement (Panavia F 2.0). Each adhesive was applied to the treated amalgam surfaces following its manufacturer's instructions. The specimens were placed in a bonding clamp, and nanocomposite resin columns, 2.38 mm in diameter and 2.00 mm in height, were photocured (40 seconds, 500 mW/cm) against the treated amalgam surfaces. The specimens were stored for 24 hours in 37°C deionized water and underwent shear bond strength testing at a crosshead speed of 0.5 mm/min. Data were analyzed using 2-way analysis of variance and post hoc analysis with the Tukey test at 95% confidence. The mean (SD) shear bond strength values ranged from 12.3 (1.2) MPa for aluminum oxide-treated surfaces bonded with OptiBond Solo Plus to 25.9 (4.6) MPa for silicoated surfaces bonded with Panavia F 2.0. All bonding agents produced the highest shear bond strength when the amalgam surface was silicoated. These results indicate that composite can be effectively bonded to amalgam via silicoating.
Topics: Dental Amalgam; Composite Resins; Dental Bonding; Surface Properties; Dental Restoration Repair; Humans; Resin Cements; Materials Testing; Shear Strength; Methacrylates; Thiones
PubMed: 38905606
DOI: No ID Found -
Naunyn-Schmiedeberg's Archives of... Jun 2024Cichorium is a genus of potential medicinal herbs that finds widespread cultivation in regions spanning Asia and Europe. Belonging to the Asteraceae family, these plants... (Review)
Review
Cichorium is a genus of potential medicinal herbs that finds widespread cultivation in regions spanning Asia and Europe. Belonging to the Asteraceae family, these plants are typically biennial or perennial in nature. Among the various explored varieties of chicory plants, the most commonly studied ones include Cichorium intybus, Cichorium endivia, and Cichorium pumilum. In Ayurveda, chicory has long been used as a remedy for many health problems. This versatile plant is renowned for its efficacy in managing conditions such as gallstones, gastroenteritis, sinus ailments, and the treatment of skin abrasions and wounds. Numerous bioactives, including polysaccharides, caffeic acid, flavonoids, coumarins, steroids, alkaloids, organic acids, triterpenoids, sesquiterpenoids, and essential oils, are present, according to a thorough phytochemical examination. The phytochemicals isolated from chicory have displayed significant therapeutic activities, including antidiabetic effects, hepatoprotective benefits, anti-obesity properties, and anti-cancer potential, as extensively documented by numerous researchers. The incorporation of these bioactive compounds into one's diet as part of a healthy lifestyle has demonstrated considerable advantages for human well-being. Green synthesis is a recent technology in which plant extracts or phytochemicals are used for synthesizing nanoparticles since plant extracts are generally less toxic and contain capping and reducing agents. This review summarizes current developments in green synthesis employing phytoconstituents from Cichorium species and extracts from various plant parts and their application to scientific problems. In order to preserve lifestyles and cure human diseases, the investigation emphasizes the therapeutic effects of the chemical components and nanoparticles obtained from the extract of Cichorium species.
PubMed: 38900250
DOI: 10.1007/s00210-024-03221-5 -
American Journal of Dentistry Jun 2024To evaluate the effect of air abrasion and polishing procedures on roughness and color stability of ceramic and composite materials after artificial accelerated aging.
PURPOSE
To evaluate the effect of air abrasion and polishing procedures on roughness and color stability of ceramic and composite materials after artificial accelerated aging.
METHODS
In this study, six restorative materials were tested: feldspathic ceramic (CEREC Blocks), glass ceramic (IPS e.max CAD), resin-based hybrid ceramic (Cerasmart), microhybrid composite (Charisma Classic), nanohybrid composite (Charisma Diamond) and nanoceramic composite (CeramXOne). Forty square-shaped composite specimens were fabricated from each composite and CAD-CAM ceramic material. Initial surface roughness measurements were performed using a profilometer and color measurements of each specimen with a spectrophotometer. Ten control specimens for each group did not receive air abrasion. The other specimens were treated by an air abrasion device and then were randomly divided into three subgroups of 10 specimens (n= 10). After air abrasion, 10 specimens of each group did not receive polishing (Air abrasion group) and others were repolished with Sof-Lex kit (Sof-Lex group) or a rubber kit (Rubber group). Surface roughness and color measurements were repeated before and after 300 hours of artificial accelerated aging (AAA). The univariate test and then three-way ANOVA and two-way ANOVA were performed for comparison of groups (α= 0.05).
RESULTS
The univariate statistical analysis revealed that the restorative materials were differently affected after air abrasion, polishing methods and AAA (P< 0.001). Three-way ANOVA showed that the surface roughness of the restorative materials increased after air abrasion and AAA (P< 0.001). Two-way ANOVA showed statistically significant differences between color changes of ceramic (CEREC and IPS e.max CAD) and composite based restorative materials (P< 0.001).
CLINICAL SIGNIFICANCE
Clinicians should be aware that air abrasion at a specified power and time significantly changes the surface roughness of the materials except for CEREC. Additionally, polishing procedures (Sof-Lex, Rubber) did not significantly reduce the surface roughness of the ceramic groups. After air abrasion, depending on the material type used clinically, restorations should be repolished to reduce roughness and ensure color stability.
Topics: Dental Polishing; Surface Properties; Composite Resins; Color; Ceramics; Materials Testing; Dental Porcelain; Dental Materials; Air Abrasion, Dental; Time Factors; Computer-Aided Design; Aluminum Silicates; Spectrophotometry; Humans; Potassium Compounds
PubMed: 38899994
DOI: No ID Found -
American Journal of Dentistry Jun 2024To investigate the effect of different chemical compositions of primers on the bond strength between nano-ceramic, polymer-infiltrated ceramic, and zirconia ceramic...
PURPOSE
To investigate the effect of different chemical compositions of primers on the bond strength between nano-ceramic, polymer-infiltrated ceramic, and zirconia ceramic materials and dual-cure cement.
METHODS
Fifty 2 mm-thick specimens were prepared from Vita Enamic, Cerasmart, and Katana Zirconia UTML. The specimens were embedded in acrylic blocks. To standardize the surfaces, 600 grit silicon carbide abrasives were applied underwater for 60 seconds. Then, each section underwent grit-blasting using Al₂O₃ with a particle size of 50 µm at 10 mm and a pressure of 2 bar for 10 seconds. Each prepared sample from the experimental groups received the appropriate primer (Z-PRIME Plus, G-Multi Primer, Alloy Primer, Clearfil Primer Plus) according to the manufacturers' instructions. Subsequently, the prepared CAD-CAM specimens underwent cementation using Duo-Link Universal Adhesive Resin Cement with a cylinder mold of 2.6 mm diameter and 3 mm height. The cement was light-cured for 20 seconds from both sides. The specimens obtained were stored in distilled water at 37°C for 24 hours. The shear bond strength test of the specimens was performed using a Bisco Shear Bond Tester device. The data were statistically analyzed using ANOVA and the Kruskal-Wallis test (P< 0.05).
RESULTS
The highest bond strength was observed in Z-Prime Plus applied specimens, regardless of material differences (Cerasmart 11.60±4.61; Vita Enamic 12.93±3.86; Katana Zirconia 13.85±4.00). The lowest bond strength, showing differences according to materials (P< 0.05), was found for Clearfil Ceramic Primer Plus-Cerasmart (7.88±3.90), Alloy Primer-Vita Enamic (7.90±2.14), and G Multi Primer-Katana Zirconia UTML (4.98±3.67).
CLINICAL SIGNIFICANCE
Failure of the restoration usually occurs at the weakest point in this three-element structure, thus correct primer selection according to material type is important. Additionally, for all CAD-CAM materials used in the study, Z-Prime Plus showed significantly greater adhesion strength than other systems so it may be more appropriate for use in clinics.
Topics: Resin Cements; Dental Bonding; Ceramics; Shear Strength; Materials Testing; Zirconium; Dental Stress Analysis; Surface Properties; Computer-Aided Design
PubMed: 38899993
DOI: No ID Found