objective: different methods have been suggested to overcome the polymerization shrinkage of composite restorations. changing the light curing protocol to improve polymerization by using new light curing units is among these methods. the new devices are more efficient, portable and durable and produce less heat. this study aimed to assess the marginal microleakage of class v composite restorati...

background: implantation failure is one of the most important factors limiting success in ivf treatment. the majority of trials have demonstrated favorable effect of endometrial injury on implantation success rate especially in women with recurrent implantation failure, while some studies failed to detect any benefit. objective: the purpose of our trial was to explore whether endometrial injury...

Fast myotomal muscle fibres were isolated from the cod (Gadus morhua L.) and the energy cost of contraction was measured under conditions simulating swimming. Fibre bundles were subjected to sinusoidal cycles of shortening and lengthening about their in situ fibre length, and stimulated at selected phases in each cycle. The preparations were poisoned with iodoacetic acid and bubbled with nitrog...

This work presents a simulation study on both energy and economics of power generation plants with inherent CO2 capture based on chemical looping combustion technologies. Combustion systems considered include a conventional chemical looping system and two extended three-reactor alternatives (exCLC and CLC3) for simultaneous hydrogen production. The power generation cycles include a combined cyc...

We have developed a simple chemical system capable of self-movement in order to study the physicochemical origins of movement. We propose how this system may be useful in the study of minimal perception and cognition. The system consists simply of an oil droplet in an aqueous environment. A chemical reaction within the oil droplet induces an instability, the symmetry of the oil droplet breaks, ...

The search of molecular structures inside a large database of chemical compounds is a critical step for many computer programs used in several domains of chemistry. During the last years, the size of many chemical databases has dramatically increased, hence in the meantime, search engines needed to be more and more powerful. The speed and the efficiency of screening processes of the chemical co...

Living systems rely on chains of energy transfer from an energy source to maintain their metabolism. This task requires functionally identified components and organizations. However, propagation of a sustained energy flux through a cascade of reaction cycles has never been reproduced at a steady state in a simple chemical system. By using energy patterning and a diffusing hub reactant, we achie...

background: the purpose of the study was to evaluate the role of progesterone/ estradiol (p4/e2) ratio as a predictive tool for clinical pregnancy in art cycles with a premature progesterone rise of >1.5 ng/ml on the day of human chorionic gonadotropin (hcg) trigger. methods: retrospective analysis was done on 569 fresh embryo transfer cycles from january 2011 to december 2012 at the infertilit...

We consider a simple model of an autocatalytic chemical reaction where a limit cycle rapidly increases to infinite period and amplitude, and disappears under variation of a parameter. We show that this bifurcation can be understood from seeing the system as a singular perturbation problem, and we find the bifurcation point by an asymptotic analysis. Scaling laws for period and amplitude are der...