Small Molecules-Driven Pancreatic ß-Cells Differentiation of Bone Marrow Mesenchymal Stem Cells

Imran Ullah,Keon Bong Oh,Yurianna Shin,Youngim Kim,Sun A Ock 한국동물생명공학회(구 한국동물번식학회) 2017 발생공학 국제심포지엄 및 학술대회 Vol.2017 No.10

Diabetes mellitus, a hyperglycemic condition, in which the patients either fail to secrete insulin because of ß-cells destruction (type I) or shows insulin resistance (type II), affecting more than 300 million people around the globe. Generation of effective ß-cells for the treatment of diabetes is a key area in modern translational medicines. Here we tried to generate porcine induced pancreatic ß-cells (piPan ß-cells) from Gal- TKO+MCP porcine bone marrow mesenchymal stem cell (pBM-MSCs) by overexpressing set of transcription factors included EGFP along with step-wise induction of small molecules. pBM-MSCs were cultured in media with 5-azacytidine for 24 hours and then proceeded with transfection using episomal transfection system. Transfected cells were replaced with basal media containing growth factors cocktail, Activin A and 2 uM of A83-01 followed by retinoic acid treatment. Finally, cells were replaced by maintenance media until maturation. After 3 days of transfection, EGFP expression was observed showing successful transfection which disappeared completely after 21 days. pBM-MSCs attained definitive endoderm morphology after Activin A treatment and formed exact pancreatic clusters after 4 weeks and 8 weeks in maintenance media, respectively. After 4 and 8 weeks, piPan ß-cells were analyzed for the expression of pancreatic markers by immunofluorescence (Insulin, PAX6, Somatostatin) and RT-qPCR (GCG, INS, NKX6.1, PDX1 and NEUROD1), which showed significantly higher expression as compared with pBM-MSCs. Morphological changes and expression of pancreatic markers revealed successfully differentiation of PiPan ß-cells; however, more in depth studies for its functional characteristic and in vivo maintenance are still in progress.

Ferroelectric and Electrical Properties of Lead-Free (K0.44Na0.52Li0.04)(Nb0.86Ta0.10Sb0.04)O3 Thin Films

Ju Sung Kim,Chang Won Ahn,Amir Ullah,Song A. Chae,Ill Won Kim 한국물리학회 2016 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.68 No.12

The Li, Ta, and Sb-substituted lead-free (K0.44Na0.52Li0.04)(Nb0.86Ta0.10Sb0.04)O3 (KNLNTS) thin films were fabricated on Pt(111)/TiO2/SiO2/Si substrates using the radio frequency (RF) magnetron sputtering method. The KNLNTS thin films were annealed at 750 C for 1 h in an oxygen ambient. The film with a thickness of 350 nm exhibited a typical ferroelectric P − E hysteresis loop without fatigue even after 1010 pulses. The KNLNTS thin film exhibited a relatively low leakage current density of 10−7 A/cm2 even up to an applied electric field of 142 kV/cm. A well-saturated piezoelectric hysteresis loop was obtained with a piezoelectric coefficient d33 of 21 pm/V.

Prostitution and AIDS in Bangladesh : Is the Ignorance Endangering Us?

A.K.M. Ahsan ULLAH Ewha Womans University Press 2003 Asian Journal of Women's Studies(AJWS) Vol.9 No.2

Effect of Mn substitution on ferroelectric and leakage current characteristics of lead-free (K_0.5Na_0.5)(Mn_xNb_1-x)O₃ thin films

Lee, S.Y.,Ahn, C.W.,Ullah, A.,Seog, H.J.,Kim, J.S.,Bae, S.H.,Kim, I.W. Elsevier 2011 CURRENT APPLIED PHYSICS Vol.11 No.3

Lead-free (K<SUB>0.5</SUB>Na<SUB>0.5</SUB>)(Mn<SUB>x</SUB>Nb<SUB>1-x</SUB>)O<SUB>3</SUB> (KNMN-x, x = 0, 0.0025, 0.0050, 0.0075, 0.0100) ferroelectric thin films were prepared by a chemical solution deposition method. The effect of Mn substitution on dielectric, ferroelectric and leakage current properties of KNMN-x thin films was investigated. It was found that 0.5-mol% Mn-doped KNMN-x film can increase the dielectric constant, as well as significantly decrease the leakage current. The KNMN-0.0050 thin film exhibited a low leakage current density of 10<SUP>-6</SUP> A/cm<SUP>2</SUP> at high electric field of 100 kV/cm. As a result, well-saturated ferroelectric P-E hysteresis loop with a large remanent polarization of ∼19.2 μC/cm<SUP>2</SUP> was obtained in the 0.5 mol% Mn-doped KNMN-x film.

Dielectric and Electromechanical Properties of Zr-Doped BNT-ST Lead-Free Piezoelectric Ceramics

Amir Ullah,Mateen Ullah,Aman Ullah,A. V. Trukhanov,Ghulam Saddiq,Burhan Ullah,Aurang Zeb,Saeed Ullah Jan,김일원 한국물리학회 2019 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.74 No.6

0.72(Bi$_{0.5}$Na$_{0.5}$)Ti$_{(1-x)}$Zr$_x$O$_3$-0.28SrTiO$_3$ (BNTZ-ST) with $x$ = 0.00, 0.01, 0.02 and 0.03 were produced using a solid solution reaction procedure. Results from the X-ray diffraction (XRD) analysis showed the presence of a perovskite structure with cubic symmetry for all samples. Surface analysis was completed using field emission scanning electron microscopy (FE-SEM), and the grain size was found to decrease slightly with increasing Zr doping. The grain morphology was primarily rectangular, but morphed into a rounder shape with increases in Zr. In a dielectric constant study, the depolarization temperature was found to decrease with increasing Zr$^{+4}$ content and increasing frequency. The strain was found to be 0.34\% for the undoped samples with an equivalent dynamic strain ($S_{max}/E_{max}$) of 618 pm/V, without negative strain. However, the strain decreased slightly and hysteresis loops become slim and more symmetric, attaining a relaxor ferroelectric behavior with increasing Zr content.

Baccaurea motleyana (Rambai): nutritional, phytochemical, and medicinal overview

A. H. M. Safayet Ullah Prodhan,Farzana Sharmin Mridu 경희대학교 융합한의과학연구소 2023 Oriental Pharmacy and Experimental Medicine Vol.23 No.1

Baccaurea motleyana (Rambai) is a widely known plant for its fruits in South-East Asia, especially in Malaysia, Indonesia, and Thailand. Traditionally it is also used as a source of medicine. In this review, we summarized the use of Rambai as a food source, its physicochemical, nutritional, biochemical, and antioxidant contents, and properties, its use as traditional medicine, and its medicinal properties based on modern studies. We found that Rambai fruits are good sources of carbohydrates, proteins, vitamins, and minerals. Rambai fruits have relatively low amounts of fats, organic acids, phenolics, and antioxidants compared to many other familiar fruits. 88 phytochemicals identified by different methods are reported in this paper which have a variety of health benefits and medicinal properties. Rambai tree parts were found to exhibit antidiabetic, antibacterial, and skincare properties. No anticancer and antifungal property of Rambai has been found yet. Many more studies are required to discover more biochemical and medicinal properties of Rambai.

The effects of sintering temperatures on dielectric, ferroelectric and electric field-induced strain of lead-free Bi_0.5(Na_0.78K_0.22)_0.5TiO₃ piezoelectric ceramics synthesized by the sol-gel technique

Ullah, A.,Ahn, C.W.,Hussain, A.,Kim, I.W. Elsevier 2010 CURRENT APPLIED PHYSICS Vol.10 No.6

Lead-free Bi<SUB>0.5</SUB>(Na<SUB>0.78</SUB>K<SUB>0.22</SUB>)<SUB>0.5</SUB>TiO<SUB>3</SUB> (BNKT) piezoelectric ceramics were synthesized by the sol-gel technique. The effects of sintering temperatures on the crystal structure, microstructure, densification, dielectric, ferroelectric and electric field-induced strain behaviors of the BNKT ceramics were investigated. X-ray diffraction patterns exhibited a pure perovskite structure from 1075 to 1150 <SUP>o</SUP>C. A scanning electron microscopy study revealed an increase in grain size with increasing sintering temperature. The density of the ceramics sintered at 1150 <SUP>o</SUP>C reaches a maximum value of 5.55 g/cm<SUP>3</SUP>, which is 96% of the theoretical density. BNKT ceramics sintered at an optimum temperature of 1150 <SUP>o</SUP>C exhibited a high remnant polarization of 18.5 μC/cm<SUP>2</SUP>, a high electric field-induced strain of 0.20% and dynamic piezoelectric coefficient d<SUB>33</SUB><SUP>*</SUP> = (S<SUB>max</SUB>/E<SUB>max</SUB>) of 247 pm/V.

A Survey of Rate-Adaptation Schemes for IEEE 802.11 Compliant WLANs

( Shahbaz Khan ),( Sadiq Ullah ),( Aziz Ahmed ),( Sahibzada. A. Mahmud ) 한국인터넷정보학회 2013 KSII Transactions on Internet and Information Syst Vol.7 No.3

The IEEE 802.11 compliant stations can transmit at multiple transmission rates. Selection of an appropriate transmission rate plays a significant role in determining the overall efficiency of a communication system. The technique which determines the channel state information and accordingly selects an appropriate transmission rate is called rate-adaptation protocol. The IEEE 802.11 standard does not provide standard specification for implementing a rate-adaptation protocol for its multi-rate capable wireless stations. Due to the lack of standard specification, there is a myriad of rate-adaptation protocols, proposed by industry and various research institutes. This paper surveys the existing rate-adaptation schemes, discusses various features which contribute significantly in the process of rate-adaptation, the timing constraints on such schemes, and the performance gains in terms of throughput, delay and energy efficiency; which can be gained by the use of rate-adaptation. The paper also discusses the implication of rate-adaptation schemes on the performance of overall communication and identifies existing research challenges in the design of rate-adaptation schemes.

A Single Amino-Acid Substitution in the Sodium Transporter HKT1 Associated with Plant Salt Tolerance

Ali, Akhtar,Raddatz, Natalia,Aman, Rashid,Kim, Songmi,Park, Hyeong Cheol,Jan, Masood,Baek, Dongwon,Khan, Irfan Ullah,Oh, Dong-Ha,Lee, Sang Yeol,Bressan, Ray A.,Lee, Keun Woo,Maggio, Albino,Pardo, Jose American Society of Plant Biologists 2016 Plant Physiology Vol.171 No.3

<P>A crucial prerequisite for plant growth and survival is the maintenance of potassium uptake, especially when high sodium surrounds the root zone. The Arabidopsis HIGH-AFFINITY K+ TRANSPORTER1 (HKT1), and its homologs in other salt-sensitive dicots, contributes to salinity tolerance by removing Na+ from the transpiration stream. However, TsHKT1; 2, one of three HKT1 copies in Thellungiella salsuginea, a halophytic Arabidopsis relative, acts as a K+ transporter in the presence of Na+ in yeast (Saccharomyces cerevisiae). Amino-acid sequence comparisons indicated differences between TsHKT1; 2 and most other published HKT1 sequences with respect to an Asp residue (D207) in the second pore-loop domain. Two additional T. salsuginea and most other HKT1 sequences contain Asn (N) in this position. Wild-type TsHKT1; 2 and altered AtHKT1 (AtHKT1(N-D)) complemented K+-uptake deficiency of yeast cells. Mutant hkt1-1 plants complemented with both AtHKT1(N-D) and TsHKT1; 2 showed higher tolerance to salt stress than lines complemented by the wild-type AtHKT1. Electrophysiological analysis in Xenopus laevis oocytes confirmed the functional properties of these transporters and the differential selectivity for Na+ and K+ based on the N/D variance in the pore region. This change also dictated inward-rectification for Na+ transport. Thus, the introduction of Asp, replacing Asn, in HKT1-type transporters established altered cation selectivity and uptake dynamics. We describe one way, based on a single change in a crucial protein that enabled some crucifer species to acquire improved salt tolerance, which over evolutionary time may have resulted in further changes that ultimately facilitated colonization of saline habitats.</P>

Thermal energy performance due to convection process of nanofluid in a porous medium due to split lid motion in a right triangular enclosure

Ullah M Zaka,Hussain S T,Haq Rizwan Ul,Alzahrani A Khamis,Mallawi Fouad 한국CDE학회 2022 Journal of computational design and engineering Vol.9 No.3

In the current phenomena, a study is carried out for the convection process of nanofluid within the porous media enclosed in a triangular permeable cavity. The heat generation effect within the nanofluid is developed when the two heat sources are applied through the split lids. To analyse the behaviour of nanofluids and steam lines, we have considered an elliptic (cold, adiabatic, and heated)-shaped obstacle that is placed inside the cavity. Mathematical modelling is carried out through continuity, momentum equation, and energy equations in the form of a system of non-linear partial differential equations. These equations are produced after incorporating the relations of viscosity, density, shapes of nanoparticle, and thermal conductivity for nanofluids Constraints are adjusted according to the forced convection due to the upper moving wall of the cavity. Four different cases of the upper double lid-driven wall are considered. All the emerging parameters, namely Reynolds number $( {25 \le {\rm{Re}} \le 750} ),$ heat generation $( { - {{10}^4} \le Q \le 40} ),\ $ nanoparticle volume fraction $\ ( {0 \le \phi \le 0.2} )$, and Darcy number ${10^{ - 5}} \le Da \le {10^{ - 3}}$, are analysed through variation of velocities, temperature profile, isotherms, and streamlines. Various cases at the surface of the inner elliptical obstacle provide significant contributions in the variation of heat transfer rate and velocity profiles. Nanoparticles provide a considerable increase in the heat transfer rate. The Darcy number shows the substantial variation in the formation of the isothermal region. An increase in heat generation parameter Q provides an improvement in temperature distribution inside the cavity and it also caused the formation of a single isothermal region around the heated obstacle.