Development of lightweight high‐performance polymeric composites with functionalized nanotubes

In this article, we highlight the various properties of an ultralightweight poly(ether ketone) (PEK) composite. In this study, special emphases were laid on the preparation of low‐density, high‐performance polymeric foams with foaming agents and activators. PEK, foamed PEK, and carbon nanotube (CNT)–reinforced foamed PEK composites were considered for this study. The density of the polymer decreased with the reinforcement of the foaming agent. We also noted that with the reinforcement of the modified CNT in the foamed PEK, there were marginal increases in the density and hardness of the composites. We also noted that the mechanical properties of the CNT‐reinforced foamed PEK was on par with those of basic PEK. Thermogravimetric analysis gave us a clear indication that the thermal stability of the composites was not affected by the reinforcing foaming agent and nanoparticles. Scanning electron microscopy and transmission electron microscopy clearly indicated the formation of foams and also the dispersion of nanoparticles in the composite structure. We also observed that because of the reinforcement of multiwalled CNTs in the composite, there was an improvement in the hardness of the composite. An increase in the specific strength was observed in the foamed PEK composites. The CNT‐reinforced foamed PEK showed a marginal decrease in the specific strength without a compromise in the impact strength. The impact strength of the CNT‐reinforced foamed PEK composite was found to be similar to that of the basic PEK. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43471.     

Novel polyurethane dispersions based on renewable raw materials—Stability studies by variations of DMPA content and degree of neutralisation

Renewable resources, especially natural oils, have received increasing attention as raw materials for polymers. The synthesis and characterisation of novel aqueous polyurethane dispersions derived from rapeseed oil are investigated. The applied renewable polyol is high-hydrophobic due to the triglyceride backbone. Dimethylolpropionic acid (DMPA) as internal emulsifier was used to incorporate hydrophilic groups into the polymer chain to achieve stable self-emulsifying dispersions. By neutralisation of the carboxyl groups with triethylamine a predominately electrostatic stabilisation was generated. A weak steric stabilisation by pending chain ends exists beside the predominant electrostatic stabilisation. Outgoing from a DMPA content of 5.6 wt% related to the polymer, the content was decreased successively with the objective being to analyse the influence of ionic concentration and stability. Furthermore, the influence of the degree of neutralisation with respect to the stabilisation of these novel dispersions was investigated.     

Chemical Validation of DegS As a Target for the Development of Antibiotics with a Novel Mode of Action

Despite the availability of hundreds of antibiotic drugs, infectious diseases continue to remain one of the most notorious health issues. In addition, the disparity between the spread of multidrug-resistant pathogens and the development of novel classes of antibiotics exemplify an important unmet medical need that can only be addressed by identifying novel targets. Herein we demonstrate, by the development of the first in vivo active DegS inhibitors based on a pyrazolo[1,5-a]-1,3,5-triazine scaffold, that the serine protease DegS and the cell envelope stress-response pathway σE represent a target for generating antibiotics with a novel mode of action. Moreover, DegS inhibition is synergistic with well-established membrane-perturbing antibiotics, thereby opening promising avenues for rational antibiotic drug design.     

Evolutionary Design of Fuzzy Logic Based Position Controller for Mobile Robot

This paper develops a fuzzy logic based position controller whose membership functions are tuned by genetic algorithm. The main goal is to ensure successful velocity and position trajectories tracking between the mobile robot and the virtual reference cart. The proposed fuzzy controller has two inputs and two outputs. The first input represents the distance between the mobile robot and the reference cart. The second input is the angle formed by the straight line defined with the orientation of the robot, and the straight line that connects the robot with the reference cart. The outputs represent linear and angular velocity commands, respectively. The performance of the fuzzy controller is validated through comparison with previously developed mobile robot position controller based on control Lyapunov functions (CLF). Simulation results indicate good performance of position tracking while at the same time a substantial reduction of the control torques is achieved.     

Substrate Scope for Human Histone Lysine Acetyltransferase KAT8

Biomedically important histone lysine acetyltransferase KAT8 catalyses the acetyl coenzyme A-dependent acetylation of lysine on histone and other proteins. Here, we explore the ability of human KAT8 to catalyse the acetylation of histone H4 peptides possessing lysine and its analogues at position 16 (H4K16). Our synthetic and enzymatic studies on chemically and structurally diverse lysine mimics demonstrate that KAT8 also has a capacity to acetylate selected lysine analogues that possess subtle changes on the side chain and main chain. Overall, this work highlights that KAT8 has a broader substrate scope beyond natural lysine, and contributes to the design of new chemical probes targeting KAT8 and other members of the histone lysine acetyltransferase (KAT) family.     

Cloud computing-based parallel genetic algorithm for gene selection in cancer classification

Cancer classification is one of the main steps during patient healing process. This fact enforces modern clinical researchers to use advanced bioinformatics methods for cancer classification. Cancer classification is usually performed using gene expression data gained in microarray experiment and advanced machine learning methods. Microarray experiment generates huge amount of data, and its processing via machine learning methods represents a big challenge. In this study, two-step classification paradigm which merges genetic algorithm feature selection and machine learning classifiers is utilized. Genetic algorithm is built in MapReduce programming spirit which makes this algorithm highly scalable for Hadoop cluster. In order to improve the performance of the proposed algorithm, it is extended into a parallel algorithm which process on microarray data in distributed manner using the Hadoop MapReduce framework. In this paper, the algorithm was tested on eleven GEMS data sets (9 tumors, 11 tumors, 14 tumors, brain tumor 1, lung cancer, brain tumor 2, leukemia 1, DLBCL, leukemia 2, SRBCT, and prostate tumor) and its accuracy reached 100% for less than 25 selected features. The proposed cloud computing-based MapReduce parallel genetic algorithm performed well on gene expression data. In addition, the scalability of the suggested algorithm is unlimited because of underlying Hadoop MapReduce platform. The presented results indicate that the proposed method can be effectively implemented for real-world microarray data in the cloud environment. In addition, the Hadoop MapReduce framework demonstrates substantial decrease in the computation time.

     

Soundness and Completeness Proofs by Coinductive Methods

We show how codatatypes can be employed to produce compact, high-level proofs of key results in logic: the soundness and completeness of proof systems for variations of first-order logic. For the classical completeness result, we first establish an abstract property of possibly infinite derivation trees. The abstract proof can be instantiated for a wide range of Gentzen and tableau systems for various flavors of first-order logic. Soundness becomes interesting as soon as one allows infinite proofs of first-order formulas. This forms the subject of several cyclic proof systems for first-order logic augmented with inductive predicate definitions studied in the literature. All the discussed results are formalized using Isabelle/HOL’s recently introduced support for codatatypes and corecursion. The development illustrates some unique features of Isabelle/HOL’s new coinductive specification language such as nesting through non-free types and mixed recursion–corecursion.