Parameters determining the agglomeration behavior of anhydrous L-ornithine-L-aspartate (LOLA) crystals prepared by drowning out crystallization

Crystallization of L-ornithine-L-aspartate (LOLA) by drowning out was performed for the production of the anhydrous form of LOLA. The needle-like LOLA crystals were formed and spherically agglomerated during precipitation in a semibatch crystallizer. The primary crystal size in the agglomerate remains unchanged after completion of the crystallization. Therefore, the agglomeration process of primary crystals played an important role for controlling LOLA crystal size. The agglomeration of LOLA crystals was governed by not only the physico-chemical parameters such as the temperature and feed concentration, but also the hydrodynamic parameters such as agitation speed and feeding rate. The crystal size and the shape have been shown to be important factors in product impurity and flowability. Thus, the optimum condition of LOLA crystallization process by drowning-out could be obtained.     

Recent progress on magnetic iron oxide nanoparticles: synthesis,surface functional strategies and biomedical applications

This review focuses on the recent development and various strategies in the preparation, microstructure, and magnetic properties of bare and surface functionalized iron oxide nanoparticles (IONPs); their corresponding biological application was also discussed. In order to implement the practical in vivo or in vitro applications, the IONPs must have combined properties of high magnetic saturation, stability, biocompatibility, and interactive functions at the surface. Moreover, the surface of IONPs could be modified by organic materials or inorganic materials, such as polymers, biomolecules, silica, metals, etc. The new functionalized strategies, problems and major challenges, along with the current directions for the synthesis, surface functionalization and bioapplication of IONPs, are considered. Finally, some future trends and the prospects in these research areas are also discussed.     

A finite element ductile failure simulation method using stress-modified fracture strain model

This paper proposes a new method to simulate ductile failure using finite element analysis based on the stress-modified fracture strain model. A procedure is given to determine the stress-modified fracture strain as a function of the stress triaxiality from smooth and notched bar tensile tests with FE analyses. For validation, simulated results using the proposed method are compared with experimental data for cracked bar (tensile and bend) tests, extracted from API X65 pipes, and for full-scale burst test of gouged pipes, showing overall good agreements. Advantages in the use of the proposed method for practical structural integrity assessment are discussed.     

Control of hydroxyl group content in silica particle synthesized by the sol-precipitation process

This study investigated the control of hydroxyl groups, one of key factors determining the surface properties of silica particles synthesized by the sol-precipitation of tetraethyl orthosilicate (TEOS). Thus, a thermal gravity analysis (TGA) was used to facilitate quantitative measurements of the hydroxyl groups on the silica particles, while BET and FT-IR were used to analyze the specific surface area and functional silane groups on the silica particles, respectively. In the sol-precipitation process, silanes that include various hydroxyl groups are formed as intermediates based on the hydrolysis and condensation of TEOS. Thus, NH₃, as a basic catalyst initiating the nucleophilic substitution of TEOS, was found to accelerate the hydrolysis and increase the hydroxyl group content on the silica particles. Plus, the hydroxyl group content was also increased when increasing the concentrations of TEOS and water as the hydrolysis reactants. However, the hydroxyl group content was reduced when increasing the temperature, due to the promotion of condensation. Based on the weight loss of the particles according to the thermal analysis, the hydroxyl group content on the silica particles varied from 5.6–42.7 OH/nm² under the above reaction conditions.     

Antioxidant and Hepatoprotective Effects of the Red Ginseng Essential Oil in H(2)O(2)-Treated HepG2 Cells and CCl(4)-Treated Mice

The aim of this study was to evaluate the antioxidant mechanisms of red ginseng essential oil (REO) in cells as well as in an animal model. REO was prepared by a supercritical CO(2) extraction of waste-products generated after hot water extraction of red ginseng. In HepG2 cells, REO diminished the H(2)O(2)-mediated oxidative stress and also restored both the activity and expression of antioxidant enzymes such as superoxide dismutase, catalase and glutathione peroxidase. Administration of REO inhibited the phosphorylation of upstream mitogen-activated protein kinases (MAPKs) such as c-Jun N-terminal kinase, extracellular signal-regulated kinase, and p38. In mice, the CCl(4)-mediated elevation of serum aspartate transaminase and alanine transaminase as well as the induction of hepatic lipid peroxidation were decreased by REO administration. REO treatments also resulted in up-regulation of the antioxidant enzyme expression in the liver. Moreover, increased phosphorylations of MAPKs were inhibited after REO administration. Overall, REO seems to protect the liver from oxidative stress through the activation and induction of antioxidant enzymes via inhibition of MAPKs pathways.     

Hierarchical Management Scheme of Biometric Information Through the Synchronization of Heterogeneous Devices

As medical technology has been developing, patients’ information (medical information, disease information, etc.) has been diversely used in medical services so that patients’ biometric information can be used for remote diagnosis and examinations. However, since the complexity and uncertainty of patient treatment have been increasing, doctors’ burden due to hospital work has been also increasing. In the present paper, an analytic hierarchy process based patient information management scheme is proposed that can synchronize diverse medical devices used for patient treatment to hierarchically manage patients’ disease information. The purpose of the proposed scheme is to analyze the correlations of medical devices used in medical treatment of patients to induce hierarchical management of patients’ disease information through triangle fuzzy of pairwise comparison scales for medical treatment and efficiently perform not only hospital administrative work but also patients’ disease analysis and treatment. In addition, using the patients’ disease information collected through diverse medical devices, the proposed scheme improves the efficiency of patient treatment methods so that hospitals can calculate the importance of treatment standards in order to hierarchically identify treatment standards. Furthermore, since the proposed scheme enables efficiently selecting treatment methods for patients’ diseases, it has a characteristic of being capable of efficiently improve the ambiguousness and inaccuracy of treatment judgments and treatment compared to existing disease treatment methods. According to the results of performance evaluation, the proposed scheme improved work efficiency by 11.9% over existing techniques and reduced medical device administration costs by 10.9%. Furthermore, the proposed scheme improved patients’ satisfaction with treatment by 23.6%.     

Designing and verifying a P2P service security protocol in M2M environment

Multifunctional high-performance electronic systems in M2M(Machine-to-Machine) industry have been evolving substantially in tandem with the advancement of IT. M2M, standing for machine-to-machine communication, replaces people in cases where human intervention is hardly viable or in such fields as weather, environment or disasters where long-term monitoring is required. Yet, due to the nature of M2M devices involving wireless communication, they are exposed to intruders’ attacks. Thus, the overriding concern in M2M communication is mutual authentication and security. In this context, security communication protocols are considered worth exploring. This paper concerns designing a safe communication protocol by applying hash locks, random numbers and session keys. Instead of arguing for the security of the protocol based on mathematical theorem proving as most previous studies did, the present paper demonstrates the proposed protocol is safe against a variety of intruders’ attacks by formally verifying it using Casper/FDR. In short, the proposed protocol is verified in terms of safety, deadlock and livelock.     

A study of the bubble properties in the column flotation system

The bubble properties in the column flotation system are deeply affected by the bubble-generator type, frother dosage, and superficial gas velocity. This study is to determine the bubble-generator type, which effectively produces micro-bubbles to affect the flotation efficiency. Characteristics for two types of bubble generators like the in-line mixer and sparger are examined by bubble properties such as bubble diameter, holdup and bubble velocity. Micro bubbles generated from an in-line mixer result in the increase of the bubble rising velocity and gas holdup. Bubbles produced at the in-line mixer were more effective for operating the flotation system than that of the sparger. It means that the in-line mixer bubble generator is more effective than a sparger in designing or operating the column flotation system.     

Estimation of number of surface crystals on sodium fluoride mother crystal in crystallization

A simple model was developed to explain the surface crystals found on the clear mother crystal face. The surface crystals on the mother crystal in the reaction crystallization of sodium were mathematically estimated by using a model based on two-dimensional secondary nucleation and two-step growth mechanisms. The model predicted that the surface crystals found on the mother crystal would be sensitive to the reactant concentration and agitation speed due to their influence on the interfacial supersaturation in the crystal growth. As the bulk supersaturation increased and the molecular transport was facilitated, the number of surface crystals on the mother crystal also increased, because the interfacial supersaturation built up on the mother crystal surface was enhanced. The prediction of the number of the surface crystals on the mother crystal appeared to be consistently comparable with experimental results.