Nowadays, the technical practice uses polymers or polymer composites largely in many engineering applications due to their unique advantage of excellent mass-to-strength ratio. The objective of this article is to determine the tribological aspects of single-edge machining (turning) for extruded polyamide 6 (PA 6 E) base polymer and two types of composites namely, PA 66 GF30 and PA 6G-H ELS with varying parameters. The tribological test was conducted and analysed using a mathematical statistical method to describe the relationship between the parameters and friction force. The contact area of the tool was found to be linearly increased with the increasing feed rate. The main cutting force does not depend on the cutting speed which can happened due to the absence of local heat generation at the tool tip. In tribological testing, a transition of steady-state to unstable state friction was observed with a sound effect for different materials which mainly depends on the material combination and pv level used. For pure PA 6 E, increasing pv level resulted in a longer and lower friction steady-state phase. Whereas, a different trend can be observed for composites with the help of developed model which has good agreement with the experimental results.
Polyvinylidene fluoride (PVDF) piezoelectric sensors are widely recognized for their flexibility, high sensing accuracy, and self-powered operation. This study addresses the challenge of improving the precision of output electrical measurements in piezoelectric flexible sensors under external force. A linear relationship between the piezoelectric sheet’s response and the applied force is derived and simulated using the first piezoelectric equation. An experimental setup is then constructed to measure output voltage under varying forces, with results analyzed using least squares fitting to establish the force-voltage relationship. A comparison of theoretical and experimental results demonstrates strong alignment, validating the method’s simplicity, feasibility, and effectiveness. Both simulation and experimental findings confirm that the sensor’s output voltage increases linearly with applied force within a defined range, offering insights for enhancing sensor performance.
The effects of homogenization on the deformation behavior, microstructure evolution, and mechanical properties of the continuously cast Al–Mg–Si–Cu alloy during the Conform continuous extrusion forming process were subject to a meticulous investigation. The findings indicated that the continuously cast Al–Mg–Si–Cu alloy possesses a refined dendritic structure, with the secondary phase partially dissolved posthomogenization, yet giving rise to a multitude of dispersed precipitated phase particles. The second phase on the dense dendrite boundary enriches the substructure of deformed structure by promoting dynamic recrystallization nucleation. However, for the homogenized alloy, the dispersed particles have relatively weak refining effect on the hot deformation structure. Conform process breaks the larger second phase and the dispersed phase particles precipitated in the subsequent homogenization process. These dispersed phase particles, by pinning dislocations and grain boundaries, impede the growth of recrystallized grains at comparatively lower temperatures, thereby enabling the homogenized alloy to achieve a finer grain size. Additionally, the tensile strength of the T5 homogenized alloy has been augmented by 18.83%, attributable to the elevated concentration of solute atoms in the solid solution.
Heparin (HEP) is a form of glycosaminoglycan, that can influence physiological functions. Therefore, heparin hydrogels offer broad application prospects in tissue engineering. Here, the HEP-based injectable hydrogel was prepared using HEP and sodium-alginate (SA). To create HEP with amino groups, adipic dihydrazide was grafted to HEP using the Adipic Dihydrazide (ADH) method. Then, SA was oxidised by sodium periodate. A novel HEP-based hydrogel was formed through the Schiff base reaction. Scanning electron microscopy (SEM) showed that the pores in the hydrogel were suitable for cell growth. The cytocompatibility of the HEPbased hydrogel was investigated by MTT colorimetric assay and cell live/dead staining. The results showed that the HEP-based hydrogel has good biocompatibility, and can promote cell growth and proliferation. In conclusion, the HEP-based hydrogel can be applied in regenerative tissue engineering.
This study evaluated the effect of Punica granatum peel extracts on candida adhesion to conventional and computer-aided design and computer-aided manufacturing (CAD/CAM) denture acrylic materials. Thirty acrylic resin discs with a diameter of 10 mm and a thickness of 3 mm were prepared using conventional methods, CAD/CAM milling, and 3D printing (n = 10). To mimic clinical settings, thermocycling and mechanical brushing were applied. Surface roughness was measured before and after soaking in the Punica granatum extract. The discs were submerged in the extract to test for candida adherence, and the growth of the candida was measured as colony-forming units (CFU/mL). Paired sample t-tests, one-way ANOVA, and Tukey’s post hoc tests (α = 0.05) were used for statistical analysis. All the tested materials demonstrated a significant increase in surface roughness after soaking in the extract (p < 0.05). Candida adhesion varied between the conventional and digitally processed materials; conventional acrylic resins showed the highest mean CFU/mL, followed by 3D-printed and milled acrylic resins. This study underscores the potential of Punica granatum peel extract as a valuable addition to dental care, particularly in reducing candida adhesion on CAD/CAM denture surfaces.
Oral squamous cell carcinoma (OSCC), the predominant malignancy in the head and neck region, poses a significant challenge with a high incidence and unfavorable prognosis, notwithstanding recent modest therapeutic advances. Biodegradable microneedles have emerged as a central focus for transdermal drug delivery, offering inherent advantages such as convenience, minimal invasiveness, negligible pain, cost-effectiveness, enhancement of drug delivery efficiency, and tunability. Nanosizing of realgar, particularly in the form of orpiment, enhances its solubility and bioavailability, thereby reducing the required dosage while mitigating inherent toxicity. In this study, we introduce an advanced drug carrier in the form of a biodegradable nanorealgar sustained-release microneedles (MNs) patch. Utilizing gelatin methacryloyl (GelMA) as the matrix material, hydrogel microneedles were meticulously fabricated and crosslinked via ultraviolet irradiation to modulate drug release, facilitating transdermal nano-realgar delivery for prolonged treatment of OSCC. This patch has features such as low toxicity, high selectivity, controlled drug release, no medical waste generation, and self-administration. Mechanical properties and drug release behavior of the microneedles were thoroughly investigated. In vivo experiments employing the oral squamous cell carcinoma cell line validated the remarkable therapeutic efficacy of nano-realgar-loaded GelMA MNs. This study represents a simple, safe, environmentally benign, and highly effective novel approach for the treatment of OSCC.
Concrete is commonly utilised in construction. Curing strengthens and shrinks concrete. Reactive liquids enter concrete through shrinkage cracks. These fluids lower core pH, corroding reinforcing bars under ideal conditions. Therefore, concrete crack repair and structural integrity restoration methods must be developed. Currently, the use of synthetic polymers to repair environmentally detrimental cracks has prompted the advancement of biological therapy methods. These synthetic polymers affect the environment. The study seeks to improve concrete quality and mend cracks sustainably. In this study, Bacillus subtilis and Bacillus megaterium bacteria is used which synthesize calcium carbonate and seal small cracks. This bio-based concrete was found to enhance the mechanical strength and durability properties of M50 grade concrete, resulting in a high-strength bacterial concrete. Each bacteria have four concrete mixes like 15 ml, 30 ml, 45 ml, and 60 ml of bacteria, including one mix without bacteria. Mechanical and durability tests were performed on each combination at 7, 28, 56, and 90 days to determine its hardness. The concrete mixes without bacteria increased compressive strength by 6–11 MPa during 28–90 days. In contrast, bacterial concrete mixes rise from 10 to 16 MPa. The evaluation findings indicate a substantial enhancement in strength and durability of the concrete with bacterial mixes than concrete without bacteria. The scanning electron microscope images and Energy Dispersive Spectroscopy graphs demonstrated an increased density, as calcite carbonates filled the pores and sealed the cracks.
In this study, we investigated the protective effect of curcumin nanoparticles (cNPs) and Zinc nanoparticles (ZnNPs) in Aflatoxin induced Chronic obstructive pulmonary disease (COPD) rat model. cNPS and ZnNPs have been reported for their anti-inflammatory, anti-cancer, and other therapeutic properties. We established a mouse model of COPD induced by cigarette smoke and aflatoxin exposure. The animals were categorized into five distinct groups for our study. Group 1 represented the control mice, while Group 2 consisted of COPD rats induced by cigarette smoke and aflatoxin (referred to as C+Afla induced rats). In Group 3, we examined COPD rats induced by cigarette smoke and aflatoxin and treated with cNPs. Group 4 involved COPD rats exposed to cigarette smoke and aflatoxin, receiving treatment with ZnNPs. Lastly, Group 5 encompassed COPD rats induced by cigarette smoke and aflatoxin and simultaneously treated with both cNPs and ZnNPs. We conducted pulmonary function tests across all groups by assessing parameters such as forced expiratory volume (FEV), forced vital capacity (FVC), and airway resistance. Following these assessments, we evaluated the expression of TNF-α, IL-8, and IL-10 inflammatory biomarkers. Additionally, we examined oxidative stress status in lung tissue by measuring malondialdehyde (MDA), superoxide dismutase (SOD), catalase (CAT), and glutathione (GSH) markers levels. These markers provide insights into the balance between oxidative stress and antioxidant defense mechanisms within the lung tissue. Finally, we analyzed the lung tissue sections stained with hematoxylin and eosin (H&E) or specific stains to assess structural changes such as emphysema, airway remodeling, mucus hypersecretion and inflammatory cell infiltration. In conclusion, our findings indicated that, combining cigarette smoke with aflatoxin effectively established a COPD model. This model was assessed through pulmonary function tests measuring VT and PEF levels. Treatment with cNPs and ZnNPs significantly altered the pathophysiology of COPD in rats, leading to improved pulmonary functions, increased body weight, reduced concentration of serum inflammatory markers, downregulation of mRNA expression for oxidative stress markers, and enhanced tissue integrity as demonstrated by H&E staining.
The coordination polymer [Zn2(DABA)3(CH3OH)] (DABA = 4-dimethylaminobenzoic acid) (ZP) was synthesized via hydrothermal method using DABA and Zn(NO3)2 · 6H2O as precursors. The structure of ZP was elucidated through thermogravimetric analysis (TGA), Fourier-transforms infrared spectroscopy (FTIR), and single-crystal X-ray diffraction. The cytotoxic effects of ZP on various cell lines (A549, HepG2, Huh-7, MCF-7, LO2) were assessed using the Cell Counting Kit-8 (CCK-8) assay, revealing significant toxicity towards the MCF-7 cell line and minimal toxicity towards normal hepatocytes (LO2). Further analysis on the MCF-7 cell line using flow cytometry showed that ZP induced cell cycle arrest at the S phase and markedly decreased mitochondrial membrane potential. Western blot analysis demonstrated that ZP could increase the expression levels of cleaved poly(ADP-ribose) polymerase (PARP), cleaved caspase, and Bax proteins, while decreasing the expression of Bcl-2. These findings indicate that ZP promotes apoptosis in tumor cells through a mitochondria-mediated pathway, involving the modulation of Bcl-2 family proteins and caspases.
Combining PNIPAM with a biocompatible NIR-II photothermal agent to prepare near-infrared-responsive hydrogels holds significant importance in the field of biomedical applications. In this study, PNIPAM/Bacterial cellulose (BC)/MXene composite hydrogels were prepared by in-situ polymerization, where Nb2C MXene serving as a near-infrared photothermal agent and BC acting as enhancing filler. The composite hydrogels possess a semi-interpenetrating network structure, where PNIPAM serves as the crosslinking network backbone, and BC act as a semi-interpenetrating network, which significantly enhances the mechanical strength of the composite hydrogels. The tensile strength and compressive strength reach 35 KPa and 500 KPa, respectively, which is an order of magnitude higher than that of pure PNIPAM hydrogel. The introduction of BC and MXene did not significantly affect the thermo-sensitivity of the composite hydrogel which can rapidly undergo a phase transition and release internal moisture above LCST. Morover, the composite hydrogel exhibits excellent photothermal performance, with its temperature rapidly increasing to around 70 °C under the irradiation of 1064 nm laser. The degree of temperature fluctuations can be accurately regulated by modifying the laser intensity and exposure time. Additionally, it demonstrates good photothermal cycling stability and significant potential for photothermal therapy.
Articular cartilage injuries are prevalent in track and field long jump and can affect an athlete’s health. However, current therapeutic options cannot effectively repair the damaged cartilage tissue. It is important to find alternative treatment methods that can provide better results for injured athletes. In this study, carbon nanofibers (CNFs) were employed to enhance the properties of hyaluronic acid (HA) and develop nanocomposite hydrogel scaffolds. Bone marrow mesenchymal stem cells extracted from the joints of experimental mice were subsequently loaded onto the CNFs-HA scaffolds and evaluated for bioactivity and repair capacity. The TEM photographs of CNFs-MA displayed an orderly arrangement of fibers. Observing the FT-IR spectral characteristics of CNFs-MA revealed a telescopic vibration peak at 1700 cm−1. CNFs-HA demonstrated a rapid increase in cartilage damage repair score after 15 days, and at 1 month, the joint damage repair score of CNFs-HA was significantly different from that of pure HA and the untreated group. Based on the foregoing results, it can be inferred that CNFs-HA, as prepared, is biocompatible and efficacious in treating articular cartilage tissue injury. Furthermore, this study this study provides a reliable solution for cartilage injury treatment and establishes an experimental basis for its clinical management.
Discuss the bacteriostatic effect of a novel controlled release silver nanoparticles carotenoids-silver nanoparticle. Detect the optimal extraction conditions for carotenoids through material liquid ratio, different ultrasonic temperatures and times; Detect the optimal synthesis conditions of carotenoids-silver nanoparticle through different volume ratios, UV irradiation times, and temperatures; Detect the bacteriostatic effects on Escherichia coli and Staphylococcus albus using the minimum inhibitory concentration (MIC) and Oxford cup agar plate diffusion method. The experiment proved that the best extraction effect of carotenoids was achieved when the volume ratio of orange peel powder to ethanol was 1:25, the ultrasound time was 40 min, and the temperature was 50 °C; When the amount of carotenoid extract added is 12 mL, the concentration of silver nitrate is 8 mmol/l, the UV irradiation time is 40 min, and the ultrasound temperature is 60 °C, the synthesized carotenoids-silver nanoparticle has the highest absorbance value; carotenoids-silver nanoparticle have strong inhibitory effects on the growth of both Escherichia coli and Staphylococcus albus. As the concentration increases, the bacteriostatic effect also becomes stronger, especially the strongest inhibitory effect on Staphylococcus albus. It was shown that carotenoids-silver nanoparticle has significant bacteriostatic effects, providing new ideas for the development of bacteriostatic agents in plant resources.
This study explored the effect of elastic band resistance training combined with nano-protective gear on post-operative muscle strength and balance ability in elderly patients with hip fracture. A sample of 100 elderly patients with hip fractures who received treatment at the Department of Traumatology and Orthopedics in our hospital from July 2020 to December 2021 were selected for this study. These patients were randomly assigned to either the observation group or the control group, with 50 patients in each group. Rehabilitation exercises were conducted for both groups starting six weeks after surgery. The control group received traditional rehabilitation training, while the observation group engaged in elastic band resistance training combined with nano-protective gear. The study compared the fracture healing time, hospitalization time, and complication rate between the two groups. Additionally, the study assessed the calcaneal bone mineral density, grip strength of both upper limbs, Harris hip joint function, and daily living activity assessment scale (BADL) in both groups at 1 month, 3 months, 6 months, and 12 months after surgery. Furthermore, the balance ability (TUGT), fall efficacy (MSFE) and nursing satisfaction of the two groups of patients were evaluated 6 months after surgery. The hospitalization time and fracture healing time of patients in the observation group were significantly shorter than those in the control group. During follow-up at various time points (3, 6, and 12 months) after discharge, the observation group exhibited significantly higher Harris hip scores, BADL scores, quality of life scores, balance ability (TUGT) scores, and fall efficacy (MSFE) scores compared to the control group. Furthermore, the observation group had a lower incidence of complications and higher nursing satisfaction (92%) compared to the control group (74%). The findings of this study suggest that combining elastic band resistance training with nano-protective gear can improve postoperative muscle strength, balance ability, joint function, alleviate negative emotions, enhance daily living ability, improve quality of life, and increase nursing satisfaction in elderly patients with hip fracture.
This study investigates the performance of rubber composite combined with carbon nanotubes to improve its physicochemical properties during the vulcanization process, thereby improving the quality of basketballs. Natural rubber and butyl rubber were mixed in a 7:3 ratio to prepare a rubber composite. Subsequently, the rubber composite was mixed with carbon nanotubes. The results demonstrate that the rubber nanocomposite prepared using wet mixing exhibits thermal aging resistance. Furthermore, the rubber nanocomposite demonstrates excellent vulcanization characteristics, which can achieve a reduction in the cure time of the rubber nanocomposite exceeding 10%. Additionally, the rubber nanocomposite shows good compatibility and mechanical properties, such as elongation at break, hardness, swelling coefficient, and cross-linking density. Notably, under high sulfur and low sulfur conditions, the decrease in tensile strength of the rubber nanocomposite is significantly smaller compared to that under the normal conditions, indicating a substantial enhancement in flexural resistance for this rubber nanocomposite. In conclusion, the prepared rubber nanocomposite shows an improvement in mechanical properties, which holds valuable implications for enhancing the quality of rubber basketballs and promoting applications of rubber products.
Five kinds of 2195 aluminum-lithium alloys with different initial tempers were obtained through different heat treatment methods. The creep aging test with a constant stress of 140 MPa, at 180 °C, mechanical tensile test at room temperature and the scanning electron microscope (SEM) observation were used to study the dependence of microstructure and properties on the initial tempers of 2195 aluminum-lithium alloy under creep aging forming conditions. The results show that the creep deformation of the alloy with re-solution initial temper is the largest, followed by the solid solution, over-aging and peak aging tempers, while the aged alloy with the regression temper has the smallest creep deformation. The order of yield and tensile strength from high to low is re-solution > solid solution > peak aging > over-aging > regression treatment. The order of elongation to fraction from large to small is solid solution > re-solution > peak aging > over aging > regression treatment. Finally, the high-strength and ductility mechanism of the creep-aged alloy with the re-solution temper was revealed: uniformly distributed fine strengthening phase (T1 phase) within the grain and narrowed precipitation-free zone at grain boundaries.
There are growing concerns and worries about the safety of public facilities and equipment. Therefore, coating products with antibacterial properties have become the key to solve this problem, and there is an urgent need to develop new antibacterial architectural coatings. In this study, polystyrene nano-microspheres (PS NMS) were prepared from styrene as raw material. PS nano-microcapsules (PS NMC) were prepared by solute co-diffusion method (SCM) using PS NMS as a template, which were modified to obtain PS-OH NMC. CuS nanoparticles (CuS NPs) with antibacterial activity were further loaded to prepare CuS@PS-OH NMC with long-term antibacterial activity. The SEM results showed that the particle size of CuS@PS-OH NMC was about 410 nm, which was larger than that of PS-OH NMC. The characterization of UV and IR spectra confirmed that CuS NPs were not only encapsulated into PS NMC in large quantities, but also adhered to its surface in a small amount. CuS@PS-OH NMC has good water solubility and can slowly release Cu2+, showing good long-term antibacterial properties against Methicillin-resistant Staphylococcus aureus (MRSA). The CuS@PS-OH NMC developed in this study has excellent performance, good antibacterial effect, environmental friendliness, low price, etc. More importantly, it can efficiently and long-term inhibit MRSA, and can be used as a potential antibacterial architectural coating for special scenarios such as hospitals, schools and densely populated places, which has excellent social and economic value.
