In-vitro formation and growth kinetics of apatite on a new light-cured composite calcium phosphate cement

Calcium phosphate cements are used as synthetic bone grafts with several advantages such as biocompatibility, osteoconductivity, and moldability. In this study, the synthesis of a biocement starting from calcium hydroxide (Ca(OH)₂) and Monocalcium Phosphate Monohydrate (MCPM) was investigated. A 6?wt% Na₂HPO₄ aqueous solution along with a modified polymeric resin (RIVA(SDI)^®) were adopted as the variable liquid phase in self- and light-cure cement groups. XRD analysis and FTIR spectroscopy were used to study the phase composition. The composite microstructure was characterized by scanning electron microscopy (SEM) and the degradation rates were measured by atomic absorption spectroscopy (AAS) analysis. In addition, the effect of soaking time of the cement in simulated body fluid (SBF) on the final phase and morphology was studied. The results showed that soaking the composite in SBF has a significant influence in phase transformation into hydroxyapatite, but following a slower kinetic in light-cured composite cements. Evidences of crosslinking reactions in light-cured cements were observable, which at the same time can legitimize slower apatite formation and faster biodegradation of these composite cements.     

Synthesis and Characterization of New Cobalt(II)–Pyrazine Coordination Polymer as Precursor for Preparation of Co(II) Oxide Nanoparticles: Surprising Coordination,DFT Calculation and Spectroscopic Studies

The new 2-D cobalt(II) coordination polymer with pyrazine was synthesized surprisingly from reaction of CoCl₂ and tetrapyrido[3,2-a:2′,3′-c:3″,2″-h:2?,3?-j]phenazine (tpphz) in methanol as medium and characterized by means of Fourier transform infrared spectroscopy (FT-IR), UV–Vis spectroscopy and X-ray single crystal analysis. The results showed that coordination polymer consist of cobalt(II) chain with pyrazine-bridged which crystallizes in orthorhombic unit cell (a?=?10.1307, b?=?10.1310, c?=?10.6838 Å) and space group Pban. Density functional theory (DFT) calculations were also done to figure out the electronic structure of the compound from theoretical aspect. The electronic spectrum of coordination polymer was investigated and the DFT/TDDFT procedures were employed to assign the absorption bands. The thermal decomposition of the title compound resulted in formation of cobalt(II) oxide nanoparticles with average size of 50 nm.     

SCoBeP: Dense image registration using sparse coding and belief propagation

Image registration as a basic task in image processing has been studied widely in the literature. It is an important preprocessing step in various applications such as medical imaging, super resolution, and remote sensing. In this paper, we proposed a novel dense registration method based on sparse coding and belief propagation. We used image blocks as features, and then we employed sparse coding to find a set of candidate points. To select optimum matches, belief propagation was subsequently applied on these candidate points. Experimental results show that the proposed approach is able to robustly register scenes and is competitive as compared to high accuracy optical flow Brox et al. (2004) [1], and SIFT flow Liu et al. [2].     

Determination of optimum condition to produce nanocrystalline pyrite by solvothermal synthesis method

In this research, FeS₂ was produced by solvothermal synthesis method. For this purpose, various solvents including ethanol, 1-propanol, 2-propanol, 1-butanol and ethylenediamine were used. Results of XRD analysis showed that ethanol and 1-butanol were fairly proper to produce FeS₂. In addition, the effects of raw materials, temperature and molar ratio of materials, on process performance were investigated. The produced iron disulfide was analyzed by XRD and SEM analyses. Results indicated that usage of the couple of FeSO₄ and Na₂S₂O₃ with molar ratio 1:4 in ethanol at temperature around 200 °C were the most appropriate condition for producing pyrite. Also, result of SEM analysis showed products with nanostructures.     

Effects of silymarin on metabolic syndrome: a review

Metabolic syndrome is one of the rising global health problems and medical challenges due to several clinical complications it may cause, for example increasing the risk of myocardial infarction and hypertension. However, great attention has been directed toward determining the worthiness of herbal medicines. There are emerging studies on preventive and therapeutic effects of silymarin on different components of metabolic syndrome. Extracted from the dried seeds of milk thistle plant (Silybum marianum L.), silymarin has been used in the treatment of different diseases for many years. Several protective effects have been identified for this herb such as decreasing insulin resistance, regulating blood pressure and lipid profile, as well as antioxidant and cytoprotective effects. This review aims to discuss available human and experimental researches into the promising effects of silymarin on different elements of metabolic syndrome. All related human and experimental papers published from 2012 to date were included in this review. Reviewing different human and experimental studies into the effects of silymarin on metabolic syndrome, we deduced that silymarin possesses promising effects on different components of this syndrome. Although the complete mechanism of action and target organs for silymarin require further verification and investigation, high‐risk individuals may benefit from supplementation with this herbal medicine. © 2018 Society of Chemical Industry     

ESIV: an end-to-end secure internet voting system

Nowadays, with the growing popularity of e-Government services, security of client platforms and violation of citizen e-rights are of great concerns. Since Internet-voting protocols have no control over voter-side platforms, bribery/coercion and breaching vote’s privacy and voter’s anonymity are feasible. In fact, the voter-side platform (voter’s PC) is easily vulnerable to malicious software (cyber-attacks) and can totally breach security of the entire voting protocol. We have proposed ESIV: an end-to-end secure internet-voting system that highly guarantees: voter and server-side platform’s security, verifiability, fairness, resistance to bribery/coercion and voting authorities collusion besides simultaneous election support while preserving eligibility, anonymity, privacy and trust. In addition, we utilize Java Card 3 technology as an independent secure web-server which is connected directly to network in order to send/receive HTTP(S) requests using high-speed interfaces. This technology brings about independence from utilizing any trusted device at voter-side and provides end-to-end security. Finally, an implementation of ESIV is presented and ESIV security features are evaluated.     

Comparative role of Interface in reinforcing mechanisms of Nano silica modified by Silanes and liquid rubber in SBR composites

The objective of the present study is to discuss the role of silica-rubber interfacial interactions on vulcanization kinetics, morphology, mechanical and viscoelastic behavior of silica filled styrene butadiene rubber (SBR) composites. Three types of modifiers, namely mono- and bi-functional silanes as well as hydroxyl-terminated poly butadiene (HTPB) liquid rubber were grafted to silica surface, and composites prepared by these fillers were characterized. Results showed that modified silica, especially grafted by bi-functional silane and liquid rubber, accelerated vulcanization reactions, while pristine silica slowed down vulcanization kinetics of SBR. Morphological studies indicated that all modifications improved dispersion of silica, but HTPB-grafted silica was dispersed to a greater extent in SBR. The observed differences in mechanical and dynamic-mechanical properties of vulcanizates were correlated to the significant differences in silica-rubber and silica-silica interactions. Type of interfacial interactions, i.e. rigid covalent bonds in the bi-functional silane, flexible polymeric bonds in the liquid rubber, and weak energetic bonds in the mono-functional silane, could explain the observed differences. Although all modifications reduced filler networking, rigid covalent bonding by bi-functional silane significantly improved mechanical properties and stabilized the filler network. The mono-functional silane lacks these mechanisms. The soft and flexible interphase of HTPB could create bonds and transfer stresses between the rubber matrix and silica to some extent, however it could not improve the mechanical properties and reduce the Payne effect as much as the bi-functional silane did.