Journal of Biomimetics, Biomaterials and Biomedical Engineering Vol. 67

Abstract: The knee joint transmission mechanism of quadruped robots usually adopts a fixed transmission ratio. Because the output torque of the knee joint fluctuates greatly during the support phase, a higher requirement is set for the torque output capability of knee joint actuator. Experimental data of multiple walking gaits was collected and parameters of the four-link transmission mechanism with strut structure for the knee joint were optimized using the complex method. In order to reduce the fluctuation of the output torque of the knee joint actuator, the knee joint is expected to maintain a higher transmission ratio at angles with higher torque output requirements. The optimization result shows that due to the limitations of the four-link mechanism, the knee joint has a larger transmission ratio at smaller angles and the maximum output torque angle, and a smaller transmission ratio at larger angles. During the support phase, the output torque of the knee joint actuator is significantly smoother, which can meet the use requirements to a certain extent.

Abstract: In this paper, a modified Bi-directional Convolutional Long Short-Term Memory U-Net (BCDU-Net) neural network is presented, which aims at enhancing medical image segmentation for lung cancer diagnosis. By integrating BConvLSTM in the decoding path and densely connected convolutional layers in the encoding path, the proposed model achieves greater stability and precision in segmenting lung CT images. The addition of Batch Normalization (BN) after the up-convolutional layers accelerates convergence speed by six times. A notable feature of BCDU-Net is its adaptability to different imaging modalities, enabling it to generalize across diverse data sources by reducing overfitting, a limitation seen in many existing models. This adaptability allows the model’s ability to be integrated into various clinical environments, ensuring consistent and reliable results across different equipment. Another key contribution is the enhanced interpretability of the model, a critical improvement when compared with traditional U-Net models. BCDU-Net accurately segments complex anatomical structures, such as the left and right lungs, and precisely identifies tumors near central bronchi or trachea airways, which is crucial for lung cancer treatment planning. The proposed model was tested on the Cancer Imaging Archive (TCIA) dataset from the 2017 Lung CT Segmentation Challenge, achieving Dice Similarity Coefficients (DSC) of 97.97 for the right lung and 97.73 for the left lung. Overall, the BCDU-Net model demonstrates superior accuracy and interpretability in medical image segmentation and holds promise for broader applications in medical imaging beyond lung cancer diagnosis.

Abstract: Zinc stannate (ZTO) NPs were prepared hydrothermal for 20 hours at 200 ᵒC. Structural, morphological, and optical properties of the ZTO NPs were studied for different zinc salt types (ZnSO₄.7H₂O, Zn(CH₃COO)₂.2H₂O, and Zn (NO₃)₂•6H₂O). The X-ray diffraction studies showed the crystalline nature with a spinel crystal structure of the ZTO nanostructure. FE-SEM image showed spherical morphology with the formation of a network of aggregates. The transmittance spectra were recorded at wavelengths ranging from 200 nm to 1200 nm. In particular, their optical band gap energies were 3.65, 3.85, and 3.8 eV for three zinc salts of ZTO (ZnSO₄.7H₂O, Zn(CH₃COO)₂.2H₂O, Zn (NO₃)₂.6H₂O), respectively. The MIC showed the ZTO NPs for zinc salt ZnSO₄.7H₂O in Volumetric dilution 3.125% and 12.5 was more effective against Escherichia coli and Staphylococcus aureus from another zinc salt of ZTO NPs. Inhibition Zone assessed ZTO NPs' antibacterial efficacy against Staphylococcus aureus and Escherichia coli. With three concentrations of ZTO, the test showed that ZTO NPs have a stronger antibacterial activity against gram-positive bacteria than gram-negative bacteria. The antibacterial activity of zinc salt ZnSO₄.7H₂O was found to be 32 against Escherichia coli and 19 nm against Staphylococcus aurous, it was more effective than other zinc salt of ZTO NPs.

Abstract: The antibiotic pollutant treatment in wastewater using conventional method remains a challenge. One of the most fluoroquinolone antibiotics family used by human and animal cure is ciprofloxacin (CIP). CIP has exhibited as a recalcitrant compound in nature with concentration from ng to mg. To overcome this issue, recent technologies have applied such as photocatalysis technology for water decontamination. Furthermore, photocatalyst materials that used in this research were zinc ferrite and graphitic carbon nitride. A simple hydrothermal-coprecipitation method has succeed to synthesis zinc ferrite. While, unexfoliated graphitic carbon nitride (ZFO@ue-CN) was synthesized by calcination at 550 °C for 4 h under air condition. A heterostructure approach combining zinc ferrite and unexfoliated graphitic carbon nitride (ZFO@ue-CN) has been investigated as a potential solution. In this study, a ZFO@ue-CN was constructed by calcination method under atmosphere condition at 400 °C for 2 h. The ZFO@ue-CN has been characterized involving structural, morphological, and optical. Furthermore, ZFO@ue-CN exhibited excellent degradation performance with over 88% removal of ciprofloxacin. The heterojunction formation of ZFO@ue-CN nanocomposite provide more efficient electron transfer compared to single material. Combination between metal oxide@ue-CN can open up the new platform for simple material preparation, nevertheless it can keep the photodegradation performance. This result also emphasizes that the ZFO@ue-CN nanocomposites has prominent application for wastewater treatment.

Abstract: Aromatic and medicinal plants are a natural source of pharmaceutical compounds with curative and therapeutic properties. They have been used for centuries to treat various ailments and offer alternative options to conventional treatments. Among these plants, Marrubium vulgare L., which is widely used in traditional medicine for diabetes treatment, has antioxidant potential as well as anti-inflammatory, healing, and soothing properties, attracting increasing medical interest. In this context, the hygroscopic behavior of Marrubium vulgare L. is reported. The adsorption-desorption isotherms of Marrubium vulgare leaves were determined using the standard static gravimetric method at three temperatures (30, 40, and 50 °C) to ensure physicochemical and microbiological stability throughout the storage process. The results showed that the adsorption-desorption isotherms of all samples followed a sigmoidal pattern, consistent with other agricultural products discussed in the literature. The optimal moisture content for conservation was also determined. The GAB (Guggenheim-Anderson-de Boer) and double polynomial models were the most suitable for describing the sorption curves. The adsorption-desorption data were examined to determine the moisture content of the monolayer (3.4-9.7%), properties of sorbed water in porous structures and surfaces, total heat of wetting, net isosteric heat of sorption, spreading pressure, differential entropy, and enthalpy-entropy compensation. It was also observed that the spreading pressure and average pore radius increase with rising relative humidity and temperature, leading to the appearance of defects on the surface of Marrubium vulgare leaves. Compensation theory is essential to consider when evaluating the impact of temperature on the adsorption-desorption properties. The Gibbs free energy was positive for sorption, indicating that the process is non-spontaneous.

Abstract: Dolomite is a raw carbonate mineral rich in contents with calcium, magnesium and oxide compounds also including other minor impurities from other compounds. It could be easily found in sedimentary rock which is most likely known as dolostone associated with limestone and chalk carbonates. This mineral has been used in a variety of industries including agricultural, metallurgy, constructions, biomass and others. Currently, there are abundant sources of local dolomite minerals but have very limited applications when compared to other types of carbonate minerals. This was contributed by the lack of basic technical information on dolomite properties and no extensive research has been done to evaluate the new potential of this mineral. Therefore, this paper made a brief review on the important characteristics, properties and thermal behavior of dolomite and based on these findings discussed the dolomite's suitability and potential to be used as bioceramics and in biomedical applications.

Abstract: Polyvinyl alcohol (PVA) is a non-toxic, thermoplastic polymer that is completely biodegradable. So it is based on many composite materials for biomedical applications. In this study, various specimens were prepared by solvent casting method and then tested by tensile, FTIR, contact angle, SEM, antibacterial and cytotoxicity test. The results obtained showed the tensile strength decreased with the addition of PEG and then tended to improve after the addition of collagen and nano-titanium oxide. The wettability test shows the prepared specimens changed from hydrophobic to hydrophilic properties. The biological properties explained that the prepared composite had a better antibacterial effect and none of the samples had a toxic effect.

Abstract: Total knee arthroplasty is a successful procedure for treating chronic degenerative knee pathologies, many patients are dissatisfied with the results of the standard design. Improper tibia rotation of the implant is suspected to contribute to post-operative pain, polyethylene wears, aseptic loosening, and instability. Many factors can influence the alteration of knee kinematics after surgery including differences in implant design. Using magnetic resonance imaging, tibia rotation in a normal knee has -15.0º and -2.5º in weight-bearing males neutral tibia rotation, and tibia rotation in postoperative patients has 2.1º and 9.5º using computer tomography. In this study, a knee joint implant was developed to facilitate a high range of motion. Tibia rotation was observed with the axes of knee motion joint implants varied from 0°, 2°, 3° to 5° and knee bend measurements at 30°, 60°, 90°, 120°, and 150° of knee flexion using the knee kinematic motion simulator and the results will be compared with the results from magnetic resonance imaging and computer tomography. Using statistical analysis resulted for 0° and 2° kinematics alignment, the p-value of the development product is 0.072 and 0.054 (p > 0.05), for 3° and 5° kinematics alignment, the p-value of the development product is 0.039 and 0.031 (p ˂ 0.05). Thus, the kinematics development product at 0° and 2° kinematics alignment are similar to a normal human knee joint. Evaluation of knee kinematics implant using a knee motion simulator is expected to become a standard procedure before performing total knee arthroplasty surgery. This similarity in kinematics knee implant with a normal knee is to be expected to reduce postoperative pain, polyethylene wears, aseptic loosening, and instability during deep knee flexion and minimize the risk of implant failure.