Numerical Analysis of Stress Force on Vessel Walls in Atherosclerotic Plaque Removal through Coronary Rotational Atherectomy.

Coronary rotational atherectomy is an effective technique for treating cardiovascular disease by removing calcified tissue using small rotary grinding tools. However, it is difficult to analyze the stress force on vessel walls using experiments directly. Using computational fluid dynamics is a better way to study the stress force characteristics of the burr grinding procedure from a fluid dynamics perspective. For this purpose, physical and simulation models of atherosclerotic plaque removal were constructed in this study. The simulation results show that smaller ratios between the burr and arterial diameter (B/A = 0.5) result in a more stable flow field domain. Additionally, the pressure and stress force generated by the 4.5 mm diameter grinding tool reach 92.77 kPa and 10.36 kPa, surpassing those of the 2.5 mm and 3.5 mm grinding tools. The study has demonstrated the use of computational fluid dynamics to investigate wall shear stress characteristics in medical procedures, providing valuable guidance for optimizing the procedure and minimizing complications.

Mandibular resection and defect reconstruction guided by a contour registration-based augmented reality system: A preclinical trial.

The aim of this study was to verify the feasibility and accuracy of a contour registration-based augmented reality (AR) system in jaw surgery. An AR system was developed to display the interaction between virtual planning and images of the surgical site in real time. Several trials were performed with the guidance of the AR system and the surgical guide. The postoperative cone beam CT (CBCT) data were matched with the preoperatively planned data to evaluate the accuracy of the system by comparing the deviations in distance and angle. All procedures were performed successfully. In nine model trials, distance and angular deviations for the mandible, reconstructed fibula, and fixation screws were 1.62 ± 0.38 mm, 1.86 ± 0.43 mm, 1.67 ± 0.70 mm, and 3.68 ± 0.71°, 5.48 ± 2.06°, 7.50 ± 1.39°, respectively. In twelve animal trials, results of the AR system were compared with the surgical guide. Distance deviations for the bilateral condylar outer poles were 0.93 ± 0.63 mm and 0.81 ± 0.30 mm, respectively (p = 0.68). Distance deviations for the bilateral mandibular posterior angles were 2.01 ± 2.49 mm and 2.89 ± 1.83 mm, respectively (p = 0.50). Distance and angular deviations for the mandible were 1.41 ± 0.61 mm, 1.21 ± 0.18 mm (p = 0.45), and 6.81 ± 2.21°, 6.11 ± 2.93° (p = 0.65), respectively. Distance and angular deviations for the reconstructed tibiofibular bones were 0.88 ± 0.22 mm, 0.84 ± 0.18 mm (p = 0.70), and 6.47 ± 3.03°, 6.90 ± 4.01° (p = 0.84), respectively. This study proposed a contour registration-based AR system to assist surgeons in intuitively observing the surgical plan intraoperatively. The trial results indicated that this system had similar accuracy to the surgical guide.

Application of an effective marker-less augmented reality image guidance method in dental implant surgery.

BACKGROUND: The existing augmented reality (AR) dental implant surgery navigation system usually uses markers to complete image guidance. However, markers often affect dentists' operations and make patients uncomfortable. METHODS: To solve the problems caused by markers, this paper proposes an effective marker-less image guidance method. After initialisation is completed by contour matching, the corresponding relationship is obtained by matching the feature points between the current frame and the preloaded initial frame. The camera pose is estimated by solving the Perspective-n-Point problem. RESULTS: The registration error of AR images is 0.731 ± 0.144 mm. The planting errors are 1.174 ± 0.241 mm at the neck, 1.433 ± 0.389 mm at the apex and 5.566 ± 2.102° for the angle. The maximum error and standard deviation meet the clinical requirements. CONCLUSIONS: We demonstrate that the proposed method can accurately guide dentists to perform dental implant surgery.

Phosphate-functionalized ramie stalk adsorbent for efficient removal of Zn2+ from water: adsorption performance, mechanism, and fixed-bed column treatment of real wastewater.

A highly efficient adsorbent functionalized with phosphate groups made from a local agricultural waste, ramie stalk, was designed for Zn2+ removal from water. SEM, EDS, FTIR, zeta potential, and XPS tests were used to study the morphology and properties of modified ramie stalk (RS-P). The results showed that the phosphate groups were successfully grafted to the surface of the ramie stalk, which has a multilayered and porous structure and can provide large adsorption sites. Adsorption performance and mechanism were investigated in the static and dynamic adsorption experiments. The adsorption kinetics of Zn2+ by RS-P were better fitted by the pseudo-second-order model, indicating chemical adsorption. Adsorption isotherm was better described by Redlich-Peterson isotherm, which suggested heterogeneous and multi-site adsorption, with a maximum adsorption capacity of 0.558 mmol g-1. The characterization of adsorbents before and after adsorption indicated that a combined action of electrostatic interaction and ion exchange was the primary mechanism of adsorption. Dynamic adsorption experiments with fixed-bed column displayed excellent water treatment capabilities. RS-P exhibited good reusability in 5 cycles without much deterioration in its adsorption performances. Complex co-existing ions impaired Zn2+ adsorption during real wastewater treatment. This research benefits agricultural waste recycling and provides safe water to ensure economic, social, and environmental sustainability.

Evolution of novel grinding tool in removing coronary artery calcification tissue process.

Coronary rotational atherectomy (CRA) means of use a tiny grinding tool to rotate at high speed in the blood vessels, so as to remove calcified tissue, effectively enlarge the inner diameter of the vessels, which is an important tool for the treatment of cardiovascular calcified blockage. However, excessive grinding force, temperature and debris size can lead to serious surgical complications and endanger the patient life during CRA. This study introduces the design, fabrication and performance verification process of a novel grinding tool, and investigates the influence of tool geometrical parameters and grinding parameters The experimental results showed that: the novel grinding tool can effectively remove the simulated calcified tissue by grinding. The geometrical size of tools plays an important effect on the grinding properties, which can result in increasing grinding force, temperature and debris size with the increase of tool diameters. In addition, with the increase of rotational speed, the grinding force and temperature increase gradually, while the debris size decreases as the rotational speed increases. The increasing inner diameter of bone can also lead to a decrease in grinding force and temperature slightly. All the obtained results can give effective guidance for clinical operations.

Augmented reality for oral and maxillofacial surgery: The feasibility of a marker-free registration method.

BACKGROUND: Recognition of markers in the augmented reality system can reduce the additional cost of a guide plate required for the removal of benign tumours in oral and maxillofacial surgery, but the use of markers often has complex problems. METHOD: In order to avoid the complex problem of using markers, an augmented reality system based on a marker-free registration method was proposed to track the contour of the mandible edge. Use the computer to perform preoperative planning on the jaw model, select and mark the path of maxillofacial lesion resection. RESULTS: This method has an error of the surface matching was 0.6453 ± 0.2826 $0.6453\pm 0.2826$ mm, and an error of the surgical resection was 0.4858 ± 0.3712 $0.4858\pm 0.3712$ mm. CONCLUSIONS: We demonstrate that the system can accurately enhance the display of the surgical path and provide guidance for the tradition of maxillofacial surgery.

Metabolomic navigated Citrus waste repurposing to restore amino acids disorder in neural lesion.

The fruit juice food industry produces huge waste annually, mainly Citrus peel and seeds. We investigated their chemical composition using hydrophilic interaction chromatography (HILIC-) and reverse phase liquid chromatography tandem mass spectrometry (RPLC-MS/MS), revealing 277 compounds, mainly containing flavonoids and limonoids. As the primary representative component in Citrus waste, limonin was selected to be explored new bio-functions. We applied Zebrafish larvae to study the metabolomic response invoked by limonin. The differential metabolites (DMs) varied depending on the exposing concentration of limonin. Enrichment analysis indicated that the identified DMs related to inflammation and neurologic disorders, including epilepsy which were newly discovered for limonoids and Citrus waste. Limonin was found to restore amino acids disorder to take neuroprotection against epilepsy. Our findings provided a new bio-function and purpose for Citrus waste and limonoids. Also, we demonstrated a concise case to repurpose food waste for new applications under metabolome investigation.

Metabolomics Mechanism and Lignin Response to Laxogenin C, a Natural Regulator of Plants Growth.

Laxogenin C (LGC) is a natural spirostanol deriving from plant hormone which has shown growing regulation similar to those of brassinosteroids. In the present study, LGC showed a promoting effect on tomato seed germination and seedling growth in a dose-dependent manner. We applied LC-MS/MS to investigate metabolome variations in the tomato treated with LGC, which revealed 10 differential metabolites (DMs) related to KEGG metabolites, associated with low and high doses of LGC. Enrichment and pathway mapping based on the KEGG database indicated that LGC regulated expressions of 2-hydroxycinnamic acid and l-phenylalanine to interfere with phenylalanine metabolism and phenylpropanoids biosynthesis. The two pathways are closely related to plant growth and lignin formation. In our further phenotypic verification, LGC was confirmed to affect seedling lignification and related phenylpropanoids, trans-ferulic acid and l-phenylalanine levels. These findings provided a metabolomic aspect on the plant hormone derivates and revealed the affected metabolites. Elucidating their regulation mechanisms can contribute to the development of sustainable agriculture. Further studies on agrichemical development would provide eco-friendly and efficient regulators for plant growth control and quality improvement.

Mesoscopic simulation study on the structural transition of comb-shaped block copolymer lamellae on chemically patterned substrates: from vertical to lateral.

Directed self-assembly of polymers on chemically homogeneous and heterogeneous patterns is of considerable interest for nanolithography and nanofluidic devices. By employing dissipative particle dynamics (DPD) technology, we explore the nanoscale phase separation of comb-like block copolymers (CBCPs) confined at chemically homogeneous and heterogeneous substrates. Herein, the geometric and energetic influences of striped substrates on the microphases are firstly studied using various geometries of annular stripes for the heterogeneous substrates. Different parameters including the stripe geometry, substrate selectivity, and film thickness are studied systematically. T-Junction lamellae and acclivitous alignment are achieved on the heterogeneous substrates because of the synergy of geometrical effects of the striped pattern from heterogeneous substrates together with weak preference of the substrates toward one of the CBCP components. In this study, we provide a detailed understanding of microphase separation of CBCPs on the heterogeneous substrates, and the approach outlined in the present study offers a crucial tool for experimentalists to design CBCP thin films with complex device-oriented structures.