The purpose of this laboratory study was to formulate and characterize the graphene oxide-poly(methyl methacrylate) resin composite with an intended use as bone cement. Graphene oxide was fabricated through ultrasonication route. The autopolymerization resin (Eco Cryl Cold, Protechno, Vilamalla Girona, Spain) was used to prepare the specimens of required dimensions for different testing parameters. The control group (C-group) was prepared as such. However, for GO1-group, 0.024 wt/wt.-% of graphene oxide was incorporated in a resin matrix and GO2-group was a composite with 0.048 wt/wt.-% of graphene oxide in a resin matrix. TEM examination of graphene oxide sheets demonstrated them in the range of ∼500 nm to ∼2 µm. The mechanical properties were characterized using three-point bending and wear resistance, while material properties were assessed through transmission electron microscope, scanning electron microscopy, Fourier-transform infrared spectroscopy, Raman spectroscopy, X-ray diffraction, differential scanning calorimetry and thermo-gravimetric analysis. The results suggest that 0.024 wt/wt.-% and 0.048 wt/wt.-% of loading of GO have no effect on the physiochemical characteristics. However, thermal characteristics might slightly be improved. According to the analysis of variance results (p < 0.05, n = 5), wear resistance and bending strength of both GO1 and GO2 groups significantly improved compared to C-group. The bending strength of GO2 improved to 87.0 ± 7.2 MPa from 65.9 ± 11.5 MPa of C-group. Scanning electron microscopy examination of the fractured surface demonstrated granule like structure where the graphene oxide sheets might be covered inside PMMA. The use of GO-PMMA composites favorably enhances the mechanical properties of bone cement.

Resilient denture liners (RDLs) change their hardness in a short time. Hence, their usefulness is limited to the short term only. Therefore, this laboratory study investigated the influence of graphene oxide (GO) nanosheets incorporation on the longevity of a commercially available RDL material. An autopolymerizing acrylic-based RDL was selected for this purpose. The control group (G 0 ) was prepared as such according to the manufacturer's instructions.However, for the G 1 group, 0.1 wt/wt% of GO nanosheet was incorporated in powder of RDL. Similarly, G 2 group and G 3 group were the composites of 0.3 and 0.6 wt/wt% of the GO-resin matrix. A total of 60 disk-shaped samples were prepared, having three subgroups with 15 disks each (n = 15). Surface roughness, water contact angle, Shore A hardness, water sorption, and solubility parameters were evaluated using a two-way analysis of variance (p < .05). GO nanosheets facilitated in reducing the hardness of RDL without affecting the surface roughness and wettability properties. Additionally, statistically reduced water solubility and sorption values were observed in G 3 group, that is, 0.69 ± 0.25% and 0.93 ± 0.18%, respectively, compared to 1.17 ± 0.13% and 1.41 ± 0.18%, respectively, of the control group at the end of 14-day water immersion. The incorporation of GO nanosheets seems a viable option for the enhanced physical properties and clinical life of RDLs.

Objectives The aim of this study was to establish a relationship between quadriceps tendon stiffness and its properties and variations in the body mass index (BMI) and segmental mass. Methods This study was conducted in 3 groups according to their BMI (A, low [<18.5 kg/m2]; B, normal [18.5–25.0 kg/m2]; and C, high [>25.0 kg/m2]). All of the participants included had a sedentary lifestyle and did not do any weightlifting or any kind of sports activity in the previous 6 months. Ultrasound measurements were performed on the participants’ lower right extremities, since it was the dominant side for all of the participants. Results A total of 40 healthy untrained men participated in the study. The mean age of the participants ± SD was 22.1 ± 1.3 years; the age ranges for groups A (n = 6), B (n = 18), and C (n = 16) were 19–23, 19–25, and 20–25 years, respectively; 28 of the participants were nonsmokers, and 12 of were smokers. A strong statistical difference (all P < .05) was witnessed for most of the parameters (BMI, body fat mass, dominant leg body fat content, fat‐free mass index, tendon thickness, and strain ratio) among the groups. Conclusions The length of the tendon did not show a significant increase with an increase in the BMI, body fat mass, dominant leg body fat content, and fat‐free mass index. However, a greater intensification was observed for the thickness of the tendon with a significant increase in tendon stiffness (with the use of external reference material).

This study aimed to determine the reinforcing effect of two weight ratios of Gum Arabic (GA) natural biopolymer, i.e., 0.5% and 1.0% in the powdered composition of glass ionomer luting cement. GA powder was oxidized and GA-reinforced GIC in 0.5 and 1.0 wt.% formulations were prepared in rectangular bars using two commercially available GIC luting materials (Medicem and Ketac Cem Radiopaque). The control groups of both materials were prepared as such. The effect of reinforcement was evaluated in terms of microhardness, flexural strength (FS), fracture toughness (FT), and tensile strength (TS). The internal porosity and water contact angle formation on the study samples were also evaluated. Film thickness was measured to gauge the effect of micron-sized GA powder in GA–GIC composite. Paired sample t-tests were conducted to analyze data for statistical significance (p < 0.05). The experimental groups of both materials containing 0.5 wt.% GA–GIC significantly improved FS, FT, and TS compared to their respective control groups. However, the microhardness significantly decreased in experimental groups of both cements compared to their respective control groups. The addition of GA powder did not cause a significant increase in film thickness and the water contact angle of both 0.5 and 1.0 wt.% GA–GIC formulations were less than 90o. Interestingly, the internal porosity of 0.5 wt.% GA–GIC formulations in both materials were observed less compared to their respective control groups. The significantly higher mechanical properties and low porosity in 0.5 wt.% GA–GIC formulations compared to their respective control group indicate that reinforcing GA powder with 0.5 wt.% in GIC might be promising in enhancing the mechanical properties of GIC luting materials.

This study aimed to determine the difference in stiffness and thickness of finger tendons between individuals who performed weight lifting (trained subjects) and those who did not perform weightlifting (untrained subjects) as well as provide real-time diagnosis of tendon stiffness. The study was divided into two groups according to their physical activity level. Individuals who performed training for their upper body for a minimum of 30 minutes, 5 days a week for at least 6 months were categorized as trained individuals, whereas those who did not train were categorized as untrained individuals. Tendon strain ratio and thickness of the index and middle fingers and body mass index (BMI) of trained and untrained adult males were measured. A total of 20 healthy individuals were enrolled for the study. Untrained individuals tended to have higher strain ratios than trained individuals. Tendon thickness between the groups was slightly different. Increased BMI was found in untrained individuals. Trained individuals had stiffer finger tendons than untrained individuals. Different activities, sedentary lifestyles or lifting weight can substantially affect the properties and size of the tendon, which can lead to strengthening or weakening of the finger tendon.