A 2-year clinical evaluation of a diphenylphosphorylazide-cross-linked collagen membrane for the treatment of buccal gingival recession

To retard collagen membrane enzymatic degradation and to increase its mechanical strength, the diphenylphosphorylazide (DPPA) technique has been demonstrated to achieve natural cross-links between peptide chains of collagen without leaving any foreign product in the cross-linked molecule. In the present prospective clinical trial, the potential of a DPPA-cross-linked type I bovine collagen membrane was evaluated in the healing of 15 buccal soft tissue recessions in 15 patients according to the biological concept of guided tissue regeneration. The recession decreased from 3.7 mm (SD 1.4) at baseline to 0.8 mm (SD 1.2) at 2 years postsurgery, corresponding to a mean root coverage of 82.2% (P <0.0001). Concurrently, the clinical attachment level decreased from 5.4 mm (SD 1.6) at baseline to 1.9 mm (SD 1.2) 2 years postsurgery, corresponding to an average clinical attachment gain of 3.5 mm (SD 1.3) (P <0.0001). The 2-year postsurgical width of the keratinized tissue was not significantly different from baseline values. More than half (53%) of the treated sites showed complete root coverage and about two-thirds (73%) of the total cases showed a 75% to 100% disappearance of the mucogingival defect. The present investigation demonstrated that the use of DPPA-cross-linked collagen membranes in the treatment of human buccal soft tissue recessions results in predictable amounts of root coverage and clinical attachment gain. Long-term randomization controlled clinical trials of this material are needed to fully evaluate its potential for treating periodontal recession.     

An evolutionary game theory–based security model in vehicular ad hoc networks

The word population is growing on a daily basis; consequently, the growth of commute and transport, developing efficient and intelligent transportation systems (ITS), has become one of the most popular requirements and the most significant attempts in modern urban areas containing large population. A key component of intelligent transportation systems is a vehicular ad hoc network. Devising internet‐based practical programs such as awareness of climatic conditions, geographical location, practical programs like on‐line payment services in the vehicular ad hoc network has led to safer driving, prevention of deadly accidents, transportation improvement, more welfare and convenience for passengers, and even offering more commercial opportunities. The special features of vehicular ad hoc network, such as intense activity, constantly‐changing topology, the vehicles' high speed, etc, will lead to challenges in gaining security. Therefore, providing vehicular ad hoc networks with security is of extreme importance in terms of users' anonymity, identification, and data privacy. In this paper, a security model is presented using a method based on evolutionary games. This method, in every vehicle, is applied as a node in the network while interacting with other vehicles; it aims at distinguishing some common attacks and defending against attackers. In this method, defending (honest) vehicles and attacking vehicles take part in an asymmetrical game; each vehicle aims at gaining the most utility and achieving its goals. The proposed method is simulated using various scenarios. The simulation results reveal that the proposed method is efficient and it reaches equilibrium and convergence at the end of the game in each scenario.     

A survey of symbiotic organisms search algorithms and applications

Nature-inspired algorithms take inspiration from living things and imitate their behaviours to accomplish robust systems in engineering and computer science discipline. Symbiotic organisms search (SOS) algorithm is a recent metaheuristic algorithm inspired by symbiotic interaction between organisms in an ecosystem. Organisms develop symbiotic relationships such as mutualism, commensalism, and parasitism for their survival in ecosystem. SOS was introduced to solve continuous benchmark and engineering problems. The SOS has been shown to be robust and has faster convergence speed when compared with genetic algorithm, particle swarm optimization, differential evolution, and artificial bee colony which are the traditional metaheuristic algorithms. The interests of researchers in using SOS for handling optimization problems are increasing day by day, due to its successful application in solving optimization problems in science and engineering fields. Therefore, this paper presents a comprehensive survey of SOS advances and its applications, and this will be of benefit to the researchers engaged in the study of SOS algorithm.

     

Fault tolerance aware scheduling technique for cloud computing environment using dynamic clustering algorithm

In cloud computing, resources are dynamically provisioned and delivered to users in a transparent manner automatically on-demand. Task execution failure is no longer accidental but a common characteristic of cloud computing environment. In recent times, a number of intelligent scheduling techniques have been used to address task scheduling issues in cloud without much attention to fault tolerance. In this research article, we proposed a dynamic clustering league championship algorithm (DCLCA) scheduling technique for fault tolerance awareness to address cloud task execution which would reflect on the current available resources and reduce the untimely failure of autonomous tasks. Experimental results show that our proposed technique produces remarkable fault reduction in task failure as measured in terms of failure rate. It also shows that the DCLCA outperformed the MTCT, MAXMIN, ant colony optimization and genetic algorithm-based NSGA-II by producing lower makespan with improvement of 57.8, 53.6, 24.3 and 13.4 % in the first scenario and 60.0, 38.9, 31.5 and 31.2 % in the second scenario, respectively. Considering the experimental results, DCLCA provides better quality fault tolerance aware scheduling that will help to improve the overall performance of the cloud environment.

     

Physical,morphological, and biological studies on PLA/nHA composite nanofibrous webs containing Equisetum arvense herbal extract for bone tissue engineering

A series of herbal extract incorporated into poly(lactic acid) (PLA) composite nanofibrous scaffolds were successfully prepared by using electrospinning technique. Equisetum arvense extract (EE) and nanohydroxyapatite (nHA) in different quantities were loaded into PLA solution to fabricate composite nanofibrous webs under various electrospinning conditions. Uniform nanofibers were obtained with an average diameter of 157 ± 47 nm in the case of those containing the herbal extract. Characterization of the webs was carried out by means of Fourier transform infrared (FTIR) spectroscopy, field emission‐scanning electron microscopy (FESEM), energy‐dispersive X‐ray spectroscopy (EDX), and differential scanning calorimetry (DSC) techniques. Mechanical properties, porosity, and contact angle of the prepared webs were also determined. Releasing behavior was investigated in phosphate buffer solution (pH 7.2) medium. Moreover, cell studies and osteogenic capacity were assessed in vitro using human adipose tissue‐derived mesenchymal stem cell (AT‐MSC). Evaluations of cell attachment, spreading, and proliferation of AT‐MSC were done by SEM observation and thiazolyl blue (MTT) assay. Osteogenic differentiation capability of AT‐MSC on the nanofibrous webs was analyzed by alkaline phosphatase activity and calcium content assay. It was found that with the addition of nHA and EE to PLA nanofibrous webs, their surface hydrophobicity was reduced while the tensile strength and Young's modulus were increased satisfactorily. Regarding the samples containing EE and nHA, cellular adhesion was observed with flattened normal morphology. Osteogenic differentiation of AT‐MSC on PLA/nHA/EE webs showed the highest mineralization capacity after 3 weeks which, was about 1.8 and 3 times higher than that of PLA/nHA and tissue culture polystyrene as control, respectively. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 45343.     

Removal of CO from process gas with Sn–activated carbon in pressure swing adsorption

A pressure swing adsorption (PSA) system using activated carbon impregnated with SnCl ₂·2H ₂ O and pure activated carbon was used to remove CO from a model H ₂/CO mixture representing the steam reformer process gas. On comparing PSA results for both carbons, the CO adsorptive capacity of impregnated carbon was found to be superior to that of the pure carbon. This was confirmed by the fact that the concentration of CO, initially at 1000 ppm, was successfully reduced to 4.02% and 1.04% of its initial concentration by the pure and the impregnated activated carbons respectively in the PSA system. The species in the impregnated carbon responsible for the improved gas phase CO adsorption was found to be SnO ₂. Simulation results at a cyclic time of 600 s in the PSA operating at 10 atmospheres gave a product recovery and purity of 99.99% and 57.48%, respectively. At 6 atmospheres, the product recovery and purity were 92.17% and 77.12%, respectively. © 2000 Society of Chemical Industry     

Statistical optimization of experimental parameters for synthesis of manganese carbonate and manganese oxide nanoparticles

Taguchi robust design was used for optimization of direct precipitation reaction conditions in order to simple and fast synthesis of manganese carbonate nanoparticles. Manganese carbonate nanoparticles were synthesized in this study by addition of manganese ion solution to the aqueous carbonate reagent. Effects of several reaction variables, such as manganese and carbonate concentrations, flow rate of reagent addition and temperature on particle size of prepared manganese carbonate were investigated. The significance of these parameters in tuning the size of manganese carbonate particles was quantitatively evaluated by analysis of variance. The results showed that manganese concentration and carbonate concentration in the solutions and also flow rate have significant effects in preparation of manganese carbonate nanoparticles. Also, optimum conditions for synthesis of manganese carbonate nanoparticles via precipitation reaction were proposed. Analysis of variance showed that under the optimum condition, the size of manganese carbonate nanoparticles will be about 54 ± 12 nm. In another part of this study, solid state thermal decomposition reaction of precursor was used for preparation of Mn₂O₃ nanoparticles. The results showed that Mn₂O₃ nanoparticles synthesized via thermal decomposition of manganese carbonate nanoparticles have average size of 90 nm.     

Design a 10 kJ IS Mather Type Plasma Focus for Solid Target Activation to Produce Short-Lived Radioisotopes 12C(d,n)13N

A 10 kJ (15 kV, 88 μF) IS (Iranian Sun) Mather type plasma focus device has been studied to determine the activity of a compound exogenous carbon solid target through ¹²C(d,n)¹³N nuclear reaction. The produced ¹³N is a short-lived radioisotope with a half-life of 9.97 min and threshold energy of 0.28 MeV. The results indicate that energetic deuterons impinging on the solid target can produce yield of $ \langle y\rangle $  = 6.7 × 10^?5 with an activity of A = 6.8 × 10⁴ Bq for one plasma focus shut and A _ν  = 4 × 10⁵ Bq for 6 shut per mint when the projectile maximum deuterons energy is E _max = 3 MeV.     

Numerical study of blowing and suction slot geometry optimization on NACA 0012 airfoil

The effects of jet width on blowing and suction flow control were evaluated for a NACA 0012 airfoil. RANS equations were employed in conjunction with a Menter’s shear stress turbulent model. Tangential and perpendicular blowing at the trailing edge and perpendicular suction at the leading edge were applied on the airfoil upper surface. The jet widths were varied from 1.5% to 4% of the chord length, and the jet velocity was 0.3 and 0.5 of the free-stream velocity. Results of this study demonstrated that when the blowing jet width increases, the lift-to-drag ratio rises continuously in tangential blowing and decreases quasi-linearly in perpendicular blowing. The jet widths of 3.5% and 4% of the chord length are the most effective amounts for tangential blowing, and smaller jet widths are more effective for perpendicular blowing. The lift-to-drag ratio improves when the suction jet width increases and reaches its maximum value at 2.5% of the chord length.