Novel Layered Double Hydroxides-Hydroxyapatite/gelatin Bone Tissue Engineering Scaffolds: Fabrication, Characterization, and in Vivo Study

Developing Porous Biodegradable Scaffolds through Simple Methods is One of the Main Approaches of Bone Tissue Engineering (BTE). in This Work, a Novel BTE Composite Containing Layered Double Hydroxides (LDH), Hydroxyapatite (HA) and Gelatin (GEL) Was Fabricated using Co-Precipitation and Solvent-Casting Methods. Physiochemical Characterizations Showed that the Chemical Composition and Microstructure of the Scaffolds Were Similar to the Natural Spongy Bone. Interconnected Macropores Ranging over 100 to 600 Μm Were Observed for Both Scaffolds While the Porosity of 90 ± 0.12% and 92.11 ± 0.15%, as Well As, Young\u27s Modulus of 19.8 ± 0.41 and 12.5 ± 0.35 GPa Were Reported for LDH/GEL and LDH-HA/GEL Scaffolds, Respectively. the Scaffolds Were Degraded in Deionized Water after a Month. the SEM Images Revealed that between Two Scaffolds, the LDH-HA/GEL with Needle-Like Secondary HA Crystals Showed Better Bioactivity. According to the Alkaline Phosphatase Activity and Alizarin Red Staining Results, LDH-HA/GEL Scaffolds Demonstrated Better Bone-Specific Activities Comparing to LDH/Gel Scaffold as Well as Control Sample (P \u3c 0.05). the Rabbit Adipose Stem Cells (ASCs) Were Extracted and Cultured, Then Seeded on the LDH-HA/GEL Scaffolds after Confluence. Three Groups of Six Adult Rabbits Were Prepared: The Scaffold + ASCs Group, the Empty Scaffold Group and the Control Group. the Critical Defects Were Made on the Left Radius and the Scaffolds with or Without ASCs Were Implanted There While the Control Group Was Left Without Any Treatment. All Animals Were Sacrificed after 12 Weeks. Histomorphometric Results Showed that the Regeneration of Defects Was Accelerated by Scaffold Implantation But ASC-Seeding Significantly Improved the Quality of New Bone Formation (P \u3c 0.05). the Results Confirmed the Good Performance of LDH-HA/GEL Scaffold to Induce Bone Regeneration

Pages: 453-463 To Cite This Article: Mohammad Mehdi Keshtkar., The Falkner-Skan Flow Over a Wedge with Variable Parameters

In the present work an analysis is accomplished to study and analyze the effect of variable viscosity and also heat generation on the classical Falkner-Skan flow. The main purpose is showing the results of Falkner-Skan problem with constant and variable surface temperature and variable viscosity, involving a wide range of Prandtl and exponent m (Falkner-Skan power-law parameter).In fact, the velocity and temperature distribution are graphically shown for a wide range of Prandtl numbers from 1 to 10000. The present outcomes have been made assuming a linear correlation between fluid density and temperature. The results are achieved with the direct numerical solution of the boundary layer equations

Multi-objective optimization of cooling water package based on 3E analysis: A case study

The aim of this paper is multi-objective optimization of cooling water package based on exergetic, economic and environmental analysis (3E) employing the non-dominated sorting genetic algorithm (NSGA-II). The studied compression refrigeration cycle of cooling water package provides chilled water for cooling the plant equipment located in South Pars refinery of Iran. Different objectives scenarios as well as decision variables including various engineering constraints are simulated in EES software which makes a set of the MINLP optimization problems. In this study, four optimization scenarios i.e. the single-objective optimizations of thermodynamic, economic and environmental as well as the multi-objective optimization are performed. After comparing all the scenarios, the results show that the multi-objective optimization provides the most simultaneous satisfaction of all the 3E results leading to the exergy destruction reduction from 264.8 kW to 127.6 kW (the performance coefficient is increased from 3.872 to 7.088). Furthermore, the cold water production cost is reduced from 117.5 dollar/hour to 87.19 dollar/hour and the NOx emission is reduced from 4958 kg/year to 2645 kg/year. Finally, by employing the multi-objective optimization, the total cost of the refinery can be improved by 25.8%

Relationship between Occurrence of Guillan-Barre Syndrome and Mass Campaign of Measles and Rubella Immunization in Iranian 5-14 Years Old Children

Objective:Several case reports and epidemiologic studies have reported a relation between different vaccines including measles, rubella, and mumps and Guillain-Barre syndrome (GBS). In this study we investigated relation between receiving measles and/or rubella vaccines and occurrence of Guillain- Barre syndrome after national immunization campaign in 2003 in Iran. Material & Methods: In this study we used National Surveillance system for acute flaccid paralysis data from the beginning of 2002 to the end of 2004. We studied 5-14 year-old children. Three-year time span of the study was divided into fifteen 10 weeks periods, and number of reported and approved cases of Guillain-Barre syndrome in each time period has been analyzed supposing their distribution was according to Poisson distribution. One of time periods has been chosen in a manner that its first 4 weeks included embedded National Immunization and following 6 weeks were designated for covering incubation period of Guillin- Barre syndrome. Findings: Of total 553 reported flaccid paralysis cases in 5-15 year-old children 370 were approved to be Guillain- Barre (~67%). Estimated average incidence of Guillain-Barre syndrome in <15 year-olds is 1/100,000/year (95% CI: 0.88-13), and in 5-15 year-old children is 0.6/100,000/year (95% CI: 0.58-083). Thus, number of expected cases in 25 cases each 10 weeks time period was 23.8 of GBS that were reported in the time period which coincided with immunization campaign. Probability of occurring ≥25 cases of GBS in that time period according to Poison distribution with expected case numbers of 23.8 is equal to 0.43 (P=0.43). Conclusion:Yearly incidence rate of GBS in this study was similar to other studies. According to our results, there was no increase in GBS incidence in the 4 weeks national Immunization Campaign and 6 weeks after it in comparison to other 10 weeks periods before or after this time period

A comparison between the effects of simulation of basic CPR training and workshops on firefighters’ knowledge and skills: experimental study

Abstract Background One of the most common causes of death worldwide is cardiopulmonary arrest. Firefighters are among the first responders at the scenes of accidents and can, therefore, play a key part in performing basic cardiopulmonary resuscitation (CPR) for victims who need it. The present study was conducted to compare the effects of simulation training against workshops on the CPR knowledge and skills of firefighters in the south of Iran. Methods This experimental (Interventional) study was conducted on 60 firefighters of south of Fars province, Iran. The study was undertaken from March to July 2023. Through random allocation, the participants were divided into two groups: simulation-based training (30 members) and traditional workshop training (30 members). The participants’ CPR knowledge and practical skills were measured before, immediately after, and three months after intervention. Results The findings of the study revealed a statistically significant difference between the pretest and posttest CPR knowledge and skill mean scores of the simulation groups as compared to the workshop group (p < 0.001). As measured three months after the intervention, the firefighters’ knowledge and skill mean scores were still significantly different from their pretest mean scores (p < 0.001); however, they had declined, which can be attributed to the fact that the study population did not frequently exercise CPR. Conclusion Based on the findings of the study, even though both methods of education were effective on enhancing the firefighters’ CPR knowledge and skill, simulation training had a far greater impact than training in workshops. In view of the decline in the participants’ knowledge and skill scores over time, it is recommended that short simulation training courses on CPR should be repeated on a regular basis

Release Behavior and Signaling Effect of Vitamin D3 in Layered Double Hydroxides-Hydroxyapatite/gelatin Bone Tissue Engineering Scaffold: An in Vitro Evaluation

Incorporating the Controlled Release of Vitamin D3 (VD3) into Biodegradable Porous Scaffolds is a New Approach to Equipping Multifunctional Therapeutics for Osteoporosis. the Current Investigation Involves the Encapsulation of VD3 into Gelatin through the One-Step Desolvation Method. the Layered Double Hydroxides-Hydroxyapatite Nanocomposite (LDH-HAp) and Pure LDH Were Combined with the Gelatin-VD3 Complex to Reinforce the Porous Biodegradable Structure and Enhance the Biological Response. afterwards, Glutaraldehyde Was Used to Form Crosslinks within the Gelatin Chains. the Encapsulation Efficiency and Loading Capacity Showed Approximately 40% and 50% Reduction after Crosslinking, Respectively. the Particle Size, Zeta Potential, Contact Angle, Young\u27s Modulus and Porosity Were Measured to Find the Effect of VD3 on the Scaffolds\u27 Physiochemical Properties. to Explore the Bioactivity and Degradation Behavior, the Scaffolds Were Immersed in Simulated Body Fluid. the VD3 Release Kinetics Followed the Korsmeyer-Peppas Model and Non-Fickian Release Pattern. the Greater Osteblastic Expression Was Observed in VD3-Containing Scaffolds Due to the Higher Alkaline Phosphatase Activity Which Was Excited More by HAp (P \u3c 0.05). Alizarin Red Staining Illustrated that VD3 Induced More Calcium Deposition, Which Indicates the Signaling Role of VD3 on Osteoconductivity and Biomineralization. the Findings Provide New Insights on the VD3 Encapsulation within Hydrophilic Matrices to Protect VD3 and Enable the Signaling Ability for Bone Tissue Engineering Scaffolds, Which Could Improve the Bone Healing Efficiency

Aptamer-conjugated magnetic nanoparticles as targeted magnetic resonance imaging contrast agent for breast cancer

Early detection of breast cancer is the most effective way to improve the survival rate in women. Magnetic resonance imaging (MRI) offers high spatial resolution and good anatomic details, and its lower sensitivity can be improved by using targeted molecular imaging. In this study, AS1411 aptamer was conjugated to Fe3O4@Au nanoparticles for specific targeting of mouse mammary carcinoma (4T1) cells that overexpress nucleolin. In vitro cytotoxicity of aptamer-conjugated nanoparticles was assessed on 4T1 and HFFF-PI6 (control) cells. The ability of the synthesized nanoprobe to target specifically the nucleolin overexpressed cells was assessed with the MRI technique. Results show that the synthesized nanoprobe produced strongly darkened T2-weighted magnetic resonance (MR) images with 4T1 cells, whereas the MR images of HFFF-PI6 cells incubated with the nanoprobe are brighter, showing small changes compared to water. The results demonstrate that in a Fe concentration of 45 μg/mL, the nanoprobe reduced by 90% MR image intensity in 4T1 cells compared with the 27% reduction in HFFF-PI6 cells. Analysis of MR signal intensity showed statistically significant signal intensity difference between 4T1 and HFFF-PI6 cells treated with the nanoprobe. MRI experiments demonstrate the high potential of the synthesized nanoprobe as a specific MRI contrast agent for detection of nucleolin-expressing breast cancer cells

Nano-particle deposition in laminar annular pipe flows

The transport and deposition of nano-particles in annular pipe flows under laminar conditions were studied. The Lagrangian particle tracking method was used to simulate the Brownian diffusion of ultrafine solid particles in a three-dimensional domain. The effects of nano-particle size, flow rate, inner and outer pipe diameters, pipe length, and temperature were studied. The computational models for the deposition of nano-particles in tubular, as well as annular pipe flows, were validated. Furthermore, using the CFD simulations and the Lagrangian particle tracking results, a new correlation for evaluating the deposition fraction of nano-particles in annular pipe flows was developed. The presented results could provide guidelines for evaluating nano-particle transport and deposition in annular pipes