Dummy template molecularly imprinted polymer for omeprazole and the study of its drug binding and release properties

In this study, we tried to prepare an omeprazole (OMP)‐imprinted polymer and study its binding and release properties in an aqueous media. Because of the instability of OMP under polymerization conditions and the inability of the molecule to form effective interactions with monomers, pantoprazole (PANTO) was used as a dummy template for the imprinting process. Different monomers and solvents were evaluated in polymerization. The optimized imprinted polymer was prepared in chloroform as a porogen. Also, 4‐vinylpyridine and ethylene glycol dimethacrylate were selected as a functional monomer and a crosslinker, respectively. The optimized imprinted polymer was evaluated in a binding study. The binding and release properties of the polymer were then investigated at different pHs. Our data indicated a higher affinity of the imprinted polymer to PANTO and OMP than that of nonimprinted polymer (NIP). The maximum percentage of OMP released from the imprinted polymer was 36–41%, whereas that for the NIP was 74–85%. These data were related to the 38–43 and 29–34 μg of OMP released from the imprinted polymer and NIP, respectively. Also, the protective effect of the imprinted polymer for OMP at pH 2 was greater than that of the nonimprinted one. This study revealed that the dummy template molecular imprinting was an effective method for preparing selective imprinted cavities in a polymeric matrix, especially for the molecules that were unstable during polymerization or unable to establish effective bonds with the monomers. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 130: 4165–4170, 2013     

Nanosized micelles self-assembled from amphiphilic poly(citric acid)–poly(ε-caprolactone)–poly(citric acid) copolymers

In this study, novel ABA-type amphiphilic copolymers consisting of poly(citric acid) (PCA) (A) as hydrophilic segment and poly(ε-caprolactone) (PCL) (B) as hydrophobic block were prepared by an approach in the following two steps: (1) ring-opening polymerization (ROP) of ε-caprolactone with 1,5-pentanediol initiator to obtain a hydroxyl telechelic PCL; (2) melt polycondensation reaction of hydroxyl telechelic PCL and citric acid molecules. The prepared copolymers are capable of self-assembling into nanosized micelles in aqueous solution. The influence of the copolymer composition on the micelle dimensions was investigated. The critical micellar concentration of the copolymers is in the range of 5–6.3 × 10^?2 mg/mL which is determined by the fluorescence probe technique using pyrene. Also the results indicate that CMC of self assembled micelles is influenced by the hydrophilicity of PCA–PCL–PCA copolymers depending on the CA/CP ratio, and these micelles may find great potential as drug carriers in biomedical fields.     

Selfish node detection in ad hoc networks based on fuzzy logic

Neural Computing and Applications - Generally, the ad hoc networks work correctly only if all nodes cooperate in the routing and forwarding of the packets. However, in some cases, selfish nodes are...     

Preserving Privacy of Software-Defined Networking Policies by Secure Multi-Party Computation

In software-defined networking (SDN), controllers are sinks of information such as network topology collected from switches. Organizations often like to protect their internal network topology and keep their network policies private. We borrow techniques from secure multi-party computation (SMC) to preserve the privacy of policies of SDN controllers about status of routers. On the other hand, the number of controllers is one of the most important concerns in scalability of SMC application in SDNs. To address this issue, we formulate an optimization problem to minimize the number of SDN controllers while considering their reliability in SMC operations. We use Non-Dominated Sorting Genetic Algorithm II (NSGA-II) to determine the optimal number of controllers, and simulate SMC for typical SDNs with this number of controllers. Simulation results show that applying the SMC technique to preserve the privacy of organization policies causes only a little delay in SDNs, which is completely justifiable by the privacy obtained.

     

Minimizing data access latency in data grids by neighborhood‐based data replication and job scheduling

In Data Grid systems, quick data access is a challenging issue due to the high latency. The failure of requests is one of the most common matters in these systems that has an impact on performance and access delay. Job scheduling and data replication are two main techniques in reducing access latency. In this paper, we propose two new neighborhood‐based job scheduling strategies and a novel neighborhood‐based dynamic data replication algorithm (NDDR). The proposed algorithms reduce the access latency by considering a variety of practical parameters for decision making and the access delay by considering the failure probability of a node in job scheduling, replica selection, and replica placement. The proposed neighborhood concept in job scheduling includes all the nodes with low data transmission costs. Therefore, we can select the best computational node and reduce the search time by running a hierarchical and parallel search. NDDR reduces the access latency through selecting the best replica by performing a hierarchical search established based on the access time, storage queue workload, storage speed, and failure probability. NDDR improves the load balancing and data locality by selecting the best replication place considering the workload, temporal locality, geographical locality, and spatial locality. We evaluate our proposed algorithms by using Optorsim Simulator in two scenarios. The simulations confirm that the proposed algorithms improve the results compared with similar existing algorithms by 11%, 15%, 12%, and 10% in terms of mean job time, replication frequency, mean data access latency, and effective network usage, respectively.     

An enhancement of task scheduling in cloud computing based on imperialist competitive algorithm and firefly algorithm

The Journal of Supercomputing - Cloud computing is an Internet-based approach in which all applications and files are hosted in a cloud consisting of thousands of computers that are linked in...     

Sleepy-LRU: extending the lifetime of non-volatile caches by reducing activity of age bits

The Journal of Supercomputing - Emerging non-volatile memories (NVMs) are known as promising alternatives to SRAMs in on-chip caches. However, their limited write endurance is a major challenge...     

Parametric optimization of the dark fermentation process for enhanced biohydrogen production from the organic fraction of municipal solid waste using Taguchi method

In this work, the Taguchi method was used to optimize the dark fermentative H₂ production from the organic fraction of municipal solid waste (OFMSW). The experiments were planned using the L16 orthogonal array design with each trial conducted at different levels of substrate concentration, inoculum-to-substrate ratio (ISR), and temperature. Based on the results, the optimal setting of the process parameters was the substrate concentration of 6 g-VS/L, ISR 0.5, and temperature of 55 °C. Furthermore, substrate concentration was the most important parameter affecting bio-H₂ production among the three process parameters considered. Finally, a confirmation experiment under optimal conditions yielded 62.5 mL H₂/g-VS_added, which was higher than all the bio-H₂ yield values obtained in the other conditions tested in this study. The measured and predicted bio-H₂ yields in the verification test were also very close to each other, confirming the reliability of the Taguchi method in optimizing the bio-H₂ production process.     

Protocol encompassing ultrasound/Fe3O4 nanoparticles/persulfate for the removal of tetracycline antibiotics from aqueous environments

Clean Technologies and Environmental Policy - The presence of residual antibiotics in the environment is one of the major global concerns, and it is imperative to control their discharge in water...