Efficacy of the Biomaterials 3 wt%-nanostrontium-hydroxyapatite-enhanced Calcium Phosphate Cement (nanoSr-CPC) and nanoSr-CPC-incorporated Simvastatin-loaded Poly(lactic-co-glycolic-acid) Microspheres in Osteogenesis Improvement

Aims The purpose of this multi-phase explorative in vivo animal/surgical and in vitro multi-test experimental study was to (1) create a 3 wt%-nanostrontium hydroxyapatite-enhanced calcium phosphate cement (Sr-HA/CPC) for increasing bone formation and (2) creating a simvastatin-loaded poly(lactic-co-glycolic acid) (SIM-loaded PLGA) microspheres plus CPC composite (SIM-loaded PLGA + nanostrontium-CPC). The third goal was the extensive assessment of multiple in vitro and in vivo characteristics of the above experimental explorative products in vitro and in vivo (animal and surgical studies). Methods and results pertaining to Sr-HA/CPC Physical and chemical properties of the prepared Sr-HA/CPC were evaluated. MTT assay and alkaline phosphatase activities, and radiological and histological examinations of Sr-HA/CPC, CPC and negative control were compared. X-ray diffraction (XRD) indicated that crystallinity of the prepared cement increased by increasing the powder-to-liquid ratio. Incorporation of Sr-HA into CPC increased MTT assay (biocompatibility) and ALP activity (P \u3c 0.05). Histomorphometry showed greater bone formation after 4 weeks, after implantation of Sr-HA/CPC in 10 rats compared to implantations of CPC or empty defects in the same rats (n = 30, ANOVA P \u3c 0.05). Methods and results pertaining to SIM-loaded PLGA microspheres + nanostrontium-CPC composite After SEM assessment, the produced composite of microspheres and enhanced CPC were implanted for 8 weeks in 10 rabbits, along with positive and negative controls, enhanced CPC, and enhanced CPC plus SIM (n = 50). In the control group, only a small amount of bone had been regenerated (localized at the boundary of the defect); whereas, other groups showed new bone formation within and around the materials. A significant difference was found in the osteogenesis induced by the groups sham control (16.96 ± 1.01), bone materials (32.28 ± 4.03), nanostrontium-CPC (24.84 ± 2.6), nanostrontium-CPC-simvastatin (40.12 ± 3.29), and SIM-loaded PLGA + nanostrontium-CPC (44.8 ± 6.45) (ANOVA P \u3c 0.001). All the pairwise comparisons were significant (Tukey P \u3c 0.01), except that of nanostrontium-CPC-simvastatin and SIM-loaded PLGA + nanostrontium-CPC. This confirmed the efficacy of the SIM-loaded PLGA + nanostrontium-CPC composite, and its superiority over all materials except SIM-containing nanostrontium-CPC

Evaluating the Seismic Performance of Steel-SMA Hybrid Braces

The seismic performance of hybrid braces composed of steel and shape memory alloy (SMA) was investigated in this paper. Six types of hybrid braces were used, constituted by SMA content of 0, 20, 40, 60, 80, and 100%. A nonlinear dynamic analysis was performed under El Centro earthquake records, with the maximum acceleration of 0.6g and 0.9g. Our results showed that the seismic performance, i.e., the amount of energy absorption and residual strain, of steel–SMA hybrid braces depends on the SMA content. The optimal value of SMA content was 20%, as, at this concentration, a hybrid brace can be designed with good seismic performance at a justifiable fabrication cost

Detection of Hepatitis C Virus RNA in blood and saliva of transfusion-dependent thalassemia patients diagnosed with Hepatitis C

Background: The aim of the current study was to detect hepatitis C virus (HCV) RNA in blood and saliva of a population of patients with thalassemia who have HCV antibody in their serum. Materials and Methods: In this cross-sectional study, blood and saliva samples were collected and were analyzed with quantitative reverse transcription polymerase chain reaction (RT-PCR) for the detection of HCV RNA. In addition, liver-related blood tests were performed, and patients' medical history was recorded. Data were analyzed by independent samples t-test and Chi-square with a significant level of 0.05. Results: Overall, 62 adult patients (29 males and 33 females) were included. Most (87%) of the patients had major thalassemia and genotype 1a was the most common (42%) type. HCV RNA was detected in 71 and 16% of blood and saliva samples, respectively. HCV RNA was detected more in female patients (31%) (P = 0.003) and in intermediate thalassemia (50%) (P < 0.005). The mean age of the patients with positive saliva was almost 10 years older (P < 0.001), and the mean number of blood transfusion was fewer in positive saliva group (P = 0.037). The sensitivity, specificity, and positive and negative predictive values of saliva PCR was calculated to be 18%, 88%, 80%, and 69%, respectively. Conclusion: Saliva contained HCV RNA in 16% of the assessed population. The probability of detection of HCV RNA in saliva increased in older patients, less number of blood transfusions, females and intermediate thalassemia. Saliva RT-PCR demonstrated low sensitivity and high specificity with high positive predictive value in the assessed population