pH-Sensitive Hydrogels Based on (Meth)Acrylates and Itaconic Acid

Simonida Lj. Tomić,Marija M. Babić,Katarina M. Antić,Jovana S. Jovašević Vuković,Neda B. Malešić,Jovanka M. Filipović 한국고분자학회 2014 Macromolecular Research Vol.22 No.11

Novel hydrogels based on 2-hydroxyethyl methacrylate (HEMA), itaconic acid (IA) and different poly(alkylene glycol) (meth)acrylates (PAGM) (P(HEMA/IA/PAGM)) were synthesized. We investigated the influenceof different PAGM components, with acrylic or methacrylic acid residues in the main chain and ethylene glycol (EG)and/or propylene glycol (PG) units in pendant chains of varying length, on the nature and inherent properties ofP(HEMA/IA/PAGM) copolymeric hydrogels. Swelling studies revealed pH sensitive behavior of P(HEMA/IA/PAGM)samples. Hydrogel structure and morphology were characterized by Fourier transform infrared (FTIR) spectroscopyand scanning electron microscopy (SEM), which confirmed their chemical structure and differences in pore size. The shear modulus values for P(HEMA/IA/PAGM) hydrogels were close to that of PHEMA, but slightly lower thanthe value for P(HEMA/IA). Cephalexin (CEX) drug release profiles from P(HEMA/IA/PAGM) samples showed amarked dependence on the PAGM component. The presence of IA also influenced the release rate of CEX, leadingto a faster release when IA was combined with the more hydrophilic PAGM component. An in vitro assay of P(HEMA/IA/PAGM) cytotoxicity showed good cell viability. The results obtained indicate that P(HEMA/IA/PAGM) hydrogelproperties were significantly dependent on the PAGM component, meaning that the type of side chains can be usedto tune the characteristics of such biomaterials. These properties make P(HEMA/IA/PAGM) copolymeric hydrogelsapplicable in biomedical and biotechnological fields and controlled drug delivery.

Therapeutic Drug Monitoring : When is it Practicable?

Maling, T.J.B. Medical Publications Korea 1979 Medical Progress Vol.6 No.8

Surface functionalization of honeycomb-patterned porous poly(ε-caprolactone) films by interfacial polymerization of aniline

Male, U.,Jo, E.J.,Park, J.Y.,Huh, D.S. IPC Science and Technology Press 2016 Polymer Vol.99 No.-

We present a new and facile strategy for the fabrication of conducting honeycomb-patterned porous films through interfacial polymerization. Polymer solutions containing poly(ε-carprolactone) (PCL) and benzoyl peroxide (BPO) in chloroform was fabricated under high humid conditions to obtain PCL-BPO honeycomb patterned films. The films were treated with aqueous aniline hydrochloride solution to polymerize aniline at the interface of the PCL film and aniline hydrochloride solution. PCL-BPO films served dual role of a template as well as an oxidant. The proposed strategy retains the electrical conductivity of polyaniline as well as the mechanical strength and biodegradable properties of PCL. In contrast with in-situ templated bulk polymerization methods, the proposed method exhibits the advantage of retaining porosity without causing any wreckage.

Graphene oxide incorporated poly(ε-caprolactone) honeycomb-patterned porous polymer films by the breath figure method

Male, U.,Shin, B. K.,Huh, D. S. Springer Science + Business Media 2017 Macromolecular Research Vol.25 No.3

Hypnotics in the Hospital

Maling, T.J.B. Medical Publications Korea 1986 Medical Progress Vol.8 No.12

The Effect of Corporate Governance on the Board of Directors’ Characteristics and Sustainability Disclosure: An Empirical Study from Thailand

Malee JATURAT,Kusuma DAMPITAKSE,Chanongkorn KUNTONBUTR 한국유통과학회 2021 The Journal of Asian Finance, Economics and Busine Vol.8 No.12

The objective of this research is to investigate how the board of directors’ characteristics influence sustainability disclosures with the mediating effect of corporate governance. The independent variables are the characteristics of the board of directors, which consist of the presence of women on the boards, presence of directors aged over 50 years old, education level, education field, board tenure, and compensation. The dependent variable is sustainability disclosures, which is measured by the GRI standard disclosure, whereas the mediator variable is the CG score. Research samples are 460 companies listed on the Stock Exchange of Thailand (SET). Path Analysis is used to examine the correlation between the board of directors’ characteristics, CG score, and GRI standard disclosure. The research findings show that senior boards, the education field, and compensation motivation have an effect on sustainability disclosures, whereas corporate governance is a mediator of the effect of the education field of boards on sustainability disclosures. This finding should help shareholders to choose individuals with suitable characteristics to serve on the board of directors, and, as a result, shareholders should anticipate a profitable result to be generated, while the business of the company is conducted in a sustainable way.

Coupling of breath figure method with interfacial polymerization: Bottom-surface functionalized honeycomb-patterned porous films

Male, Umashankar,Shin, Bo Kyoung,Huh, Do Sung Butterworth Scientific Ltd. etc. 2017 Polymer Vol. No.

<P><B>Abstract</B></P> <P>A new and facile method was designed for the fabrication of asymmetrically polyaniline (PANI) functionalized polystyrene (PS) honeycomb-patterned porous films in a single step. The method involves the coupling of breath figure process with an interfacial polymerization, wherein the PS solution containing benzoyl peroxide in an organic solvent was cast under humid conditions over an aqueous solvent containing aniline and methane sulfonic acid. PANI was coated on the bottom surface at the organic/aqueous interface by an interfacial polymerization method, whereas a porous patterned PS was fabricated on the top surface by the breath figure method. The films revealed a translucent insulating PS top surface and a conducting green PANI bottom surface. The obtained films represented asymmetrical composition, color, morphology, conductivity, and contact angle on either surface.</P> <P><B>Highlights</B></P> <P> <UL> <LI> First report on asymmetric functionalized honeycomb patterned films. </LI> <LI> Film was obtained by coupling interfacial polymerization with breath figure process. </LI> <LI> It has asymmetrical color, composition, morphology, contact angle and conductivity. </LI> <LI> These can be used in applications where asymmetrical property is a requirement. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Polyaniline decorated honeycomb-patterned pores: Use of a reactive vapor in breath figure method

Male, Umashankar,Shin, Bo Kyoung,Huh, Do Sung Butterworth Scientific Ltd. etc. 2017 Polymer Vol. No.

<P><B>Abstract</B></P> <P>A new strategy is proposed to obtain pore functionalized honeycomb-patterned porous films by in-situ polymerization during breath figure process. The polystyrene with benzoyl peroxide mixture in chloroform was casted under reactive vapor conditions, generated by pumping air through aqueous aniline hydrochloride solution. The resulting films showed honeycomb patterned porous morphology with polyaniline functionalized pores. The formation of polyaniline was confirmed from color, conductivity, and UV-Visible studies. The strategy can be extended to obtain various pore functionalized films by choosing one reactant in polymer solution and other in humid vapors.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Pore functionalized ordered porous films by reactive vapor in breath figure method. </LI> <LI> It was possible by coupling interfacial polymerization with breath figure method. </LI> <LI> Functionalization achieved at condensed reactive droplet/polymer solution interface. </LI> <LI> The strategy can be applied to obtain a wide variety of pore functionalized films. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Design and synthesis of polyaniline-grafted reduced graphene oxide via azobenzene pendants for high-performance supercapacitors

Male, Umashankar,Modigunta, Jeevan Kumar Reddy,Huh, Do Sung Butterworth Scientific Ltd. etc. 2017 Polymer Vol. No.

<P><B>Abstract</B></P> <P>To increase the pseudo-capacitance and cycle stability of polyaniline (PANI), PANI was covalently attached to reduced graphene oxide (rGO) via azobenzene (Azo) units. The rGO-Azo composite was first synthesized and subsequently used for the in situ chemical polymerization of aniline to form PANI-rGO-Azo composites. The Azo units on rGO functioned as spacers to prevent the agglomeration of rGO and increase the solubility of rGO to assist in the in situ polymerization of aniline to form PANI-rGO-Azo composite. The Azo units act as linkers for the covalent attachment of PANI chains to graphene, thereby enhance the overall performance of the composite materials. The electrochemical properties of the composites were evaluated by fabricating symmetric two-electrode cell configuration and also compared with three electrode system. The charge transfer resistance of PANI is reduced from 6.6 Ω to 2.9 Ω, by grafting PANI onto rGO-Azo. The specific capacitance of PANI-rGO-Azo (328 F g<SUP>-1</SUP>) is higher than that of PANI (270 F g<SUP>-1</SUP>) and rGO-Azo (114 F g<SUP>-1</SUP>). The electrochemical performance of PANI was enhanced by grafting of PANI onto rGO-Azo.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Charger transfer resistance of PANI is reduced by grafting onto rGO-Azo. </LI> <LI> Knee frequency of PANI-rGO-Azo was higher than PANI. </LI> <LI> 80% of initial capacitance was retained even after 1500 charge-discharge cycles. </LI> <LI> PANI-rGO-Azo shows higher electrochemical performances than PANI. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Low-resource YouTube comment encoding for Luganda sentiment classification performance

Abdul Male Ssentumbwe,YuChul Jung(정유철),Hyunah Lee(이현아),Byeong Man Kim(김병만) 한국디지털콘텐츠학회 2020 한국디지털콘텐츠학회논문지 Vol.21 No.5

The recent boom in social networks usage has generated some multilingual opinion data for low-resource languages. Luganda is one of the major languages in Uganda, thus it is a low-resource language and Luganda corpora for sentiment analysis especially for YouTube is not easily available. In this paper, we propose assumptions to guide collection of Luganda comments using Luganda YouTube video opinions for sentiment analysis. We evaluate the suitability of our clean YouTube comments (158) dataset for sentiment analysis using selected machine learning and deep learning classification algorithms. Given the low-resource setting, the dataset performs best with Gaussian Naive Bayes for machine learning (55%) and deep learning Multilayer Perceptron sequential model scoring (68.8%) when dataset splitting is at 10% for test set with Luganda comment segmentation.