Chwee Teck Lim

Bio: Chwee Teck Lim is an academic researcher from National University of Singapore. The author has contributed to research in topics: Circulating tumor cell & Cancer. The author has an hindex of 97, co-authored 558 publications receiving 39718 citations. Previous affiliations of Chwee Teck Lim include Singapore–MIT alliance & Massachusetts Institute of Technology.

Electrospinning of gelatin fibers and gelatin/PCL composite fibrous scaffolds.

Abstract: In this article, ultrafine gelatin (Gt) fibers were successfully produced with the use of the electrical spinning or electrospinning technique. A fluorinated alcohol of 2,2,2-trifluoroethanol (TFE) was used as the dissolving solvent. The morphology of the electrospun gelatin fibers was found to be dependent on the alteration of gelatin concentration ranging from 2.5% w/v to 12.5% w/v at 2.5% increment intervals. Based on the electrospun gelatin fibers obtained, 10% w/v gelatin/TFE solution was selected and mixed with 10% w/v poly(epsilon-caprolactone) (PCL) in TFE at a ratio of 50:50 and co-electrospun to produce gelatin/PCL composite membranes. Contact-angle measurement and tensile tests indicated that the gelatin/PCL complex fibrous membrane exhibited improved mechanical properties as well as more favorable wettability than that obtained from either gelatin or PCL alone. The gelatin/PCL fibrous membranes were further investigated as a promising scaffold for bone-marrow stromal cell (BMSC) culture. Scanning electron microscopy (SEM) and laser confocal microscopy observations showed that the cells could not only favorably attach and grow well on the surface of these scaffolds, but were also able to migrate inside the scaffold up to 114 microm within 1 week of culture. These results suggest the potential of using composite gelatin/PCL fibrous scaffolds for engineering three-dimensional tissues.

α‐Fe2O3 Nanoflakes as an Anode Material for Li‐Ion Batteries

Abstract: Nanoflakes of α-Fe2O3 were prepared on Cu foil by using a thermal treatment method. The nanoflakes were characterized by X-ray diffraction, scanning electron microscopy, high-resolution transmission electron microscopy, and Raman spectroscopy. The reversible Li-cycling properties of the α-Fe2O3 nanoflakes have been evaluated by cyclic voltammery, galvanostatic discharge–charge cycling, and impedance spectral measurements on cells with Li metal as the counter and reference electrodes, at ambient temperature. Results show that Fe2O3 nanoflakes exhibit a stable capacity of (680 ± 20) mA h g–1, corresponding to (4.05 ± 0.05) moles of Li per mole of Fe2O3 with no noticeable capacity fading up to 80 cycles when cycled in the voltage range 0.005–3.0 V at 65 mA g–1 (0.1 C rate), and with a coulombic efficiency of > 98 % during cycling (after the 15th cycle). The average discharge and charge voltages are 1.2 and 2.1 V, respectively. The observed cyclic voltammograms and impedance spectra have been analyzed and interpreted in terms of the ‘conversion reaction' involving nanophase Fe0–Li2O. The superior performance of Fe2O3 nanoflakes is clearly established by a comparison of the results with those for Fe2O3 nanoparticles and nanotubes reported in the literature.

Origin of Enhanced Stem Cell Growth and Differentiation on Graphene and Graphene Oxide

Abstract: The culture of bone marrow derived mesenchymal stem cells (MSCs), as well as the control of its differentiation toward different tissue lineage, is a very important part of tissue engineering, where cells are combined with artificial scaffold to regenerate tissues. Graphene (G) and graphene oxide (GO) sheets are soft membranes with high in-plane stiffness and can potentially serve as a biocompatible, transferable, and implantable platform for stem cell culture. While the healthy proliferation of stem cells on various carbon platforms has been demonstrated, the chemical role of G and GO, if any, in guiding uncommitted stem cells toward differentiated cells is not known. Herein, we report that the strong noncovalent binding abilities of G allow it to act as a preconcentration platform for osteogenic inducers, which accelerate MSCs growing on it toward the osteogenic lineage. The molecular origin of accelerated differentation is investigated by studying the binding abilities of G and GO toward different grow...

I and i

Abstract: There is, I think, something ethereal about i —the square root of minus one. I remember first hearing about it at school. It seemed an odd beast at that time—an intruder hovering on the edge of reality. Usually familiarity dulls this sense of the bizarre, but in the case of i it was the reverse: over the years the sense of its surreal nature intensified. It seemed that it was impossible to write mathematics that described the real world in …

疟原虫var基因转换速率变化导致抗原变异[英]／Paul H, Robert P, Christodoulou Z, et al//Proc Natl Acad Sci U S A

Abstract: 抗原变异可使得多种致病微生物易于逃避宿主免疫应答。表达在感染红细胞表面的恶性疟原虫红细胞表面蛋白1（PfPMP1）与感染红细胞、内皮细胞、树突状细胞以及胎盘的单个或多个受体作用，在黏附及免疫逃避中起关键的作用。每个单倍体基因组var基因家族编码约60种成员，通过启动转录不同的var基因变异体为抗原变异提供了分子基础。

Natural Products as Sources of New Drugs from 1981 to 2014

Abstract: This contribution is a completely updated and expanded version of the four prior analogous reviews that were published in this journal in 1997, 2003, 2007, and 2012. In the case of all approved therapeutic agents, the time frame has been extended to cover the 34 years from January 1, 1981, to December 31, 2014, for all diseases worldwide, and from 1950 (earliest so far identified) to December 2014 for all approved antitumor drugs worldwide. As mentioned in the 2012 review, we have continued to utilize our secondary subdivision of a “natural product mimic”, or “NM”, to join the original primary divisions and the designation “natural product botanical”, or “NB”, to cover those botanical “defined mixtures” now recognized as drug entities by the U.S. FDA (and similar organizations). From the data presented in this review, the utilization of natural products and/or their novel structures, in order to discover and develop the final drug entity, is still alive and well. For example, in the area of cancer, over t...