Printed Polymer and a-Si TFT Backplanes for Flexible Displays

Street, R.A.,Wong, W.S.,Ready, S.E.,Chabinyc, M.L.,Arias, A.C.,Daniel, J.H.,Apte, R.B.,Salleo, A.,Lujan, R.,Ong, Beng,Wu, Yiliang The Korean Infomation Display Society 2005 Journal of information display Vol.6 No.3

The need for low cost, flexible, thin film transistor (TFT) display backplanes has focused attention on new processing techniques and materials. We report the development of TFT backplane technology based entirely on jet-printing, using a combination of additive and subtractive processing, to print active materials or etch masks. The technique eliminates the use of photolithography and has the potential to reduce the array manufacturing cost. The printing technique is demonstrated with both amorphous silicon and polymer semiconductor TFT arrays, and we show results of small prototype displays.

P73 regulates cisplatin-induced apoptosis in ovarian cancer cells via a calcium/calpain-dependent mechanism

Al-Bahlani, S,Fraser, M,Wong, A Y C,Sayan, B S,Bergeron, R,Melino, G,Tsang, B K Nature Publishing Group 2011 Oncogene Vol.30 No.41

<P>P73 is important in drug-induced apoptosis in some cancer cells, yet its role in the regulation of chemosensitivity in ovarian cancer (OVCA) is poorly understood. Furthermore, if and how the deregulation of p73-mediated apoptosis confers resistance to cisplatin (CDDP) treatment is unclear. Here we demonstrate that TAp73α over-expression enhanced CDDP-induced PARP cleavage and apoptosis in both chemosensitive (OV2008 and A2780s) and their resistant counterparts (C13* and A2780cp) and another chemoresistant OVCA cells (Hey); in contrast, the effect of ΔNp73α over-expression was variable. P73α downregulation attenuated CDDP-induced PUMA and NOXA upregulation and apoptosis in OV2008 cells. CDDP decreased p73α steady-state protein levels in OV2008, but not in C13*, although the mRNA expression was identical. CDDP-induced p73α downregulation was mediated by a calpain-dependent pathway. CDDP induced calpain activation and enhanced its cytoplasmic interaction and co-localization with p73α in OV2008, but not C13* cells. CDDP increased the intracellular calcium concentration ([Ca<SUP>2+</SUP>]<SUB>i</SUB>) in OV2008 but not C13* whereas cyclopiazonic acid (CPA), a Ca<SUP>2+</SUP>-ATPase inhibitor, caused this response and calpain activation, p73α processing and apoptosis in both cell types. CDDP-induced [Ca<SUP>2+</SUP>]<SUB>i</SUB> increase in OV2008 cells was not effected by the elimination of extracellular Ca<SUP>2+</SUP>, but this was attenuated by the depletion of internal Ca<SUP>2+</SUP> store, indicating that mobilization of intracellular Ca<SUP>2+]</SUP> stores was potentially involved. These findings demonstrate that p73α and its regulation by the Ca<SUP>2+</SUP>-mediated calpain pathway are involved in CDDP-induced apoptosis in OVCA cells and that dysregulation of Ca<SUP>2+</SUP>/calpain/p73 signaling may in part be the pathophysiology of CDDP resistance. Understanding the cellular and molecular mechanisms of chemoresistance will direct the development of effective strategies for the treatment of chemoresistant OVCA.</P>

비평형 열역학에 의한 업 - 힐 수송의 특성

양원강,조성우,정우준,야마우치 한국공업화학회 1998 응용화학 Vol.2 No.2

Up-hill transport used polymeric membrane was studied on the nonequilibrium thermodynamics. The Up-hill transport energy which drives the ion transport in membrane system as the chemical reaction was described in form of the dissipation function. The membrane system was confirmed to the electro chemical system. The equation in membrane system used was estimated and the correlation between the diffusion ionic conductances and ion concentration within the polymeric membrane was discussed.

Molecular Surveillance Identifies Multiple Transmissions of Typhoid in West Africa

Wong, Vanessa K.,Holt, Kathryn E.,Okoro, Chinyere,Baker, Stephen,Pickard, Derek J.,Marks, Florian,Page, Andrew J.,Olanipekun, Grace,Munir, Huda,Alter, Roxanne,Fey, Paul D.,Feasey, Nicholas A.,Weill, F Public Library of Science 2016 PLoS neglected tropical diseases Vol.10 No.9

<▼1><P><B>Background</B></P><P>The burden of typhoid in sub-Saharan African (SSA) countries has been difficult to estimate, in part, due to suboptimal laboratory diagnostics. However, surveillance blood cultures at two sites in Nigeria have identified typhoid associated with <I>Salmonella enterica</I> serovar Typhi (<I>S</I>. Typhi) as an important cause of bacteremia in children.</P><P><B>Methods</B></P><P>A total of 128 <I>S</I>. Typhi isolates from these studies in Nigeria were whole-genome sequenced, and the resulting data was used to place these Nigerian isolates into a worldwide context based on their phylogeny and carriage of molecular determinants of antibiotic resistance.</P><P><B>Results</B></P><P>Several distinct <I>S</I>. Typhi genotypes were identified in Nigeria that were related to other clusters of <I>S</I>. Typhi isolates from north, west and central regions of Africa. The rapidly expanding <I>S</I>. Typhi clade 4.3.1 (H58) previously associated with multiple antimicrobial resistances in Asia and in east, central and southern Africa, was not detected in this study. However, antimicrobial resistance was common amongst the Nigerian isolates and was associated with several plasmids, including the IncHI1 plasmid commonly associated with <I>S</I>. Typhi.</P><P><B>Conclusions</B></P><P>These data indicate that typhoid in Nigeria was established through multiple independent introductions into the country, with evidence of regional spread. MDR typhoid appears to be evolving independently of the haplotype H58 found in other typhoid endemic countries. This study highlights an urgent need for routine surveillance to monitor the epidemiology of typhoid and evolution of antimicrobial resistance within the bacterial population as a means to facilitate public health interventions to reduce the substantial morbidity and mortality of typhoid.</P></▼1><▼2><P><B>Author Summary</B></P><P>Typhoid fever, a serious bloodstream infection caused by the bacterium <I>Salmonella</I> Typhi, is a major cause of disease and death around the world. There have been limited data on the epidemiology of typhoid in many countries in sub-Saharan African, including Nigeria. Recent evidence, however, showed that typhoid was an important cause of bacteraemia in children residing in two regions of Nigeria. Here, we analyzed the whole genome sequences of 128 <I>S</I>. Typhi isolates from two studies in order to elucidate the population structure and characterize the genetic components of antimicrobial resistance. We found that the multiple <I>S</I>. Typhi genotypes identified were closely related to other <I>S</I>. Typhi from neighboring regions of Africa and that multidrug resistance (MDR) was common among these isolates, and in many cases was associated with the IncHI1 plasmid known to cause MDR typhoid. These results provide evidence that typhoid was established in Nigeria as a result of several independent introductions into the country and that there has been extensive exchange of <I>S</I>. Typhi in and around the region of West Africa. This study emphasizes the importance of surveillance to improve our understanding of the epidemiology of typhoid, which is needed to underpin public health measures to reduce the spread of disease and facilitate patient management.</P></▼2>

A Stochastic Model of Cancer Growth with Immune Response

W. Triampo,A. Boondirek,I. M. Tang,J. Wong-ekkabut,P. Picha,Y. Lenbury 한국물리학회 2006 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.49 No.4

A cellular automaton model for the growth of an avascular tumor on a two-dimensional square lattice is presented. The pattern formation and the growth of the cell population are investigated by using a Monte Carlo simulation. A microscopic description of the immune system response, including cell proliferation, cell death, and cell degradation, is used to simulate the growth. In particular, the escape rate for cancer from immune surveillance is included for consistency with experimental observations. The simulation results give rise to a growth curve with an explanation on a microscopic scale that is shown to agree well with experimental animal tumor growth and relevant biological implications. Our model clearly shows that an increase in the lysis rate leads to a decrease in the proliferation rate of cancer cells. The spatial distribution of proliferated cell and the fractal dimension of the boundary are also measured.

Public Sentiment Analysis and Topic Modeling Regarding COVID-19’s Three Waves of Total Lockdown: A Case Study on Movement Control Order in Malaysia

A.H. Alamoodi,Mohammed Rashad Baker,O.S. Albahri,B.B. Zaidan,A.A. Zaidan,Wing-Kwong Wong,Salem Garfan,A.S. Albahri,Miguel A. Alonso,Ali Najm Jasim,M. J. Baqer 한국인터넷정보학회 2022 KSII Transactions on Internet and Information Syst Vol.16 No.7

The COVID-19 pandemic has affected many aspects of human life. The pandemic not only caused millions of fatalities and problems but also changed public sentiment and behavior. Owing to the magnitude of this pandemic, governments worldwide adopted full lockdown measures that attracted much discussion on social media platforms. To investigate the effects of these lockdown measures, this study performed sentiment analysis and latent Dirichlet allocation topic modeling on textual data from Twitter published during the three lockdown waves in Malaysia between 2020 and 2021. Three lockdown measures were identified, the related data for the first two weeks of each lockdown were collected and analysed to understand the public sentiment. The changes between these lockdowns were identified, and the latent topics were highlighted. Most of the public sentiment focused on the first lockdown as reflected in the large number of latent topics generated during this period. The overall sentiment for each lockdown was mostly positive, followed by neutral and then negative. Topic modelling results identified staying at home, quarantine and lockdown as the main aspects of discussion for the first lockdown, whilst importance of health measures and government efforts were the main aspects for the second and third lockdowns. Governments may utilise these findings to understand public sentiment and to formulate precautionary measures that can assure the safety of their citizens and tend to their most pressing problems. These results also highlight the importance of positive messaging during difficult times, establishing digital interventions and formulating new policies to improve the reaction of the public to emergency situations.

Phylogeographical analysis of the dominant multidrug-resistant H58 clade of Salmonella Typhi identifies inter- and intracontinental transmission events

Wong, Vanessa K,Baker, Stephen,Pickard, Derek J,Parkhill, Julian,Page, Andrew J,Feasey, Nicholas A,Kingsley, Robert A,Thomson, Nicholas R,Keane, Jacqueline A,Weill, Franç,ois-Xavier,Edwards, Dav Nature Pub. Co 2015 Nature genetics Vol.47 No.6

The emergence of multidrug-resistant (MDR) typhoid is a major global health threat affecting many countries where the disease is endemic. Here whole-genome sequence analysis of 1,832 Salmonella enterica serovar Typhi (S. Typhi) identifies a single dominant MDR lineage, H58, that has emerged and spread throughout Asia and Africa over the last 30 years. Our analysis identifies numerous transmissions of H58, including multiple transfers from Asia to Africa and an ongoing, unrecognized MDR epidemic within Africa itself. Notably, our analysis indicates that H58 lineages are displacing antibiotic-sensitive isolates, transforming the global population structure of this pathogen. H58 isolates can harbor a complex MDR element residing either on transmissible IncHI1 plasmids or within multiple chromosomal integration sites. We also identify new mutations that define the H58 lineage. This phylogeographical analysis provides a framework to facilitate global management of MDR typhoid and is applicable to similar MDR lineages emerging in other bacterial species.

Low-dimensional modelling of n-type doped silicene and its carrier transport properties for nanoelectronic applications

Chuan, M.W.,Lau, J.Y.,Wong, K.L.,Hamzah, A.,Alias, N.E.,Lim, C.S.,Tan, M.L.P Techno-Press 2021 Advances in nano research Vol.10 No.5

Silicene, a 2D allotrope of silicon, is predicted to be a potential material for future transistor that might be compatible with present silicon fabrication technology. Similar to graphene, silicene exhibits the honeycomb lattice structure. Consequently, silicene is a semimetallic material, preventing its application as a field-effect transistor. Therefore, this work proposes the uniform doping bandgap engineering technique to obtain the n-type silicene nanosheet. By applying nearest neighbour tight-binding approach and parabolic band assumption, the analytical modelling equations for band structure, density of states, electrons and holes concentrations, intrinsic electrons velocity, and ideal ballistic current transport characteristics are computed. All simulations are done by using MATLAB. The results show that a bandgap of 0.66 eV has been induced in uniformly doped silicene with phosphorus (PSi₃NW) in the zigzag direction. Moreover, the relationships between intrinsic velocity to different temperatures and carrier concentration are further studied in this paper. The results show that the ballistic carrier velocity of PSi₃NW is independent on temperature within the degenerate regime. In addition, an ideal room temperature subthreshold swing of 60 mV/dec is extracted from ballistic current-voltage transfer characteristics. In conclusion, the PSi₃NW is a potential nanomaterial for future electronics applications, particularly in the digital switching applications.

Wafer-Scale and Wrinkle-Free Epitaxial Growth of Single-Orientated Multilayer Hexagonal Boron Nitride on Sapphire

Jang, A-Rang,Hong, Seokmo,Hyun, Chohee,Yoon, Seong In,Kim, Gwangwoo,Jeong, Hu Young,Shin, Tae Joo,Park, Sung O.,Wong, Kester,Kwak, Sang Kyu,Park, Noejung,Yu, Kwangnam,Choi, Eunjip,Mishchenko, Artem,Wi American Chemical Society 2016 Nano letters Vol.16 No.5

<P>Large-scale growth of high-quality hexagonal boron nitride has been a challenge in two-dimensional-material-based electronics. Herein, we present wafer-scale and wrinkle-free epitaxial growth of multilayer hexagonal boron nitride on a sapphire substrate by using high-temperature and low-pressure chemical vapor deposition. Microscopic and spectroscopic investigations and theoretical calculations reveal that synthesized hexagonal boron nitride has a single rotational orientation with AA' stacking order. A facile method for transferring hexagonal boron nitride onto other target substrates was developed, which provides the opportunity for using hexagonal boron nitride as a substrate in practical electronic circuits. A graphene field effect transistor fabricated on our hexagonal boron nitride sheets shows clear quantum oscillation and highly improved carrier mobility because the ultraflatness of the hexagonal boron nitride surface can reduce the substrate-induced degradation of the carrier mobility of two-dimensional materials.</P>

<i>DLEC1</i> is a functional 3p22.3 tumour suppressor silenced by promoter CpG methylation in colon and gastric cancers

Ying, J,Poon, F F,Yu, J,Geng, H,Wong, A H Y,Qiu, G-H,Goh, H K,Rha, S Y,Tian, L,Chan, A T C,Sung, J J Y,Tao, Q Nature Publishing Group 2009 The British journal of cancer Vol.100 No.4

<P>Promoter CpG methylation of tumour suppressor genes (TSGs) is an epigenetic biomarker for TSG identification and molecular diagnosis. We screened genome wide for novel methylated genes through methylation subtraction of a genetic demethylation model of colon cancer (double knockout of <I>DNMT1</I> and <I>DNMT3B</I> in HCT116) and identified <I>DLEC1</I> (Deleted in lung and oesophageal cancer 1), a major 3p22.3 TSG, as one of the methylated targets. We further found that <I>DLEC1</I> was downregulated or silenced in most colorectal and gastric cell lines due to promoter methylation, whereas broadly expressed in normal tissues including colon and stomach, and unmethylated in expressing cell lines and immortalised normal colon epithelial cells. <I>DLEC1</I> expression was reactivated through pharmacologic or genetic demethylation, indicating a DNMT1/DNMT3B-mediated methylation silencing. Aberrant methylation was further detected in primary colorectal (10 out of 34, 29%) and gastric tumours (30 out of 89, 34%), but seldom in paired normal colon (0 out of 17) and gastric (1 out of 20, 5%) samples. No correlation between <I>DLEC1</I> methylation and clinical parameters of gastric cancers was found. Ectopic expression of <I>DLEC1</I> in silenced HCT116 and MKN45 cells strongly inhibited their clonogenicity. Thus, <I>DLEC1</I> is a functional tumour suppressor, being frequently silenced by epigenetic mechanism in gastrointestinal tumours.</P>