A broadband linearization method using a novel opto-electrical predistorter for radio-over-fiber systems

Moon, Yon-Tae,Choi, Woon-Kyung,Choi, Young-Wan Wiley Subscription Services, Inc., A Wiley Company 2010 MICROWAVE AND OPTICAL TECHNOLOGY LETTERS Vol.52 No.7

<P>A broadband linearization method with a novel opto-electrical predistorter was experimentally demonstrated. With the proposed method, the third-order intermodulation distortion was simultaneously enhanced by more than 10 dB for 510 MHz ranges and by 24 dB at 2.2 GHz without any change in electrical circuitry. © 2010 Wiley Periodicals, Inc. Microwave Opt Technol Lett 52: 1638–1640, 2010; Published online in Wiley InterScience (www.interscience. wiley.com). DOI 10.1002/mop.25240</P>

Transforming growth factor-β3-induced Smad signaling regulates actin reorganization during chondrogenesis of chick leg bud mesenchymal cells

Kim, Dongkyun,Kim, Jungsoo,Kang, Shin-Sung,Jin, Eun-Jung Wiley Subscription Services, Inc., A Wiley Company 2009 Journal of cellular biochemistry Vol.107 No.4

<P>Endochondral ossification is characterized by a significant interdependence between cell shape and cytoskeletal organization that accompanies the onset of chondrogenic signaling. However, the mechanisms mediating these interactions have not been well studied. Here, treatment with transforming growth factor (TGF)-β3 at a later stage of chondrogenesis led to activation of Smad-2 signaling and the formation of intense stress fibers, which resulted in suppressing chondrogenic differentiation of leg bud mesenchymal cells. Moreover, specific siRNA knockdown of Smad-2 reduced TGF-β3-induced stress fibers via physical interactions with β-catenin. In conclusion, our results indicate that TGF-β3-induced Smad signaling, in conjunction with β-catenin, is involved in the reorganization of the actin cytoskeleton into a cortical pattern with a concomitant rounding of cells. J. Cell. Biochem. © 2009 Wiley-Liss, Inc.</P><P>This article was published online on 28 May 2009. An error was subsequently identified. This notice is included in the online and print versions to indicate that both have been corrected 8 June 2009. J. Cell. Biochem. 107: 622–629, 2009. © 2009 Wiley-Liss, Inc.</P>

DVB-H antenna structure using Z-type hexagonal ferrite for folder-type mobile phones

Rhyu, Hanphil,Jung, Chang Won,Lee, Byungje Wiley Subscription Services, Inc., A Wiley Company 2009 MICROWAVE AND OPTICAL TECHNOLOGY LETTERS Vol.51 No.9

<P>A new internal antenna structure using a Z-type hexagonal ferrite is introduced for the DVB-H reception in folder-type mobile phones. The antenna element operates as a coupling element to excite the chassis as a radiator. Using a Z-type hexagonal ferrite, the proposed antenna can be designed with a considerably low volume of 0.75 cm<SUP>3</SUP> and meets the requirements of antenna for the DVB-H service. The high isolation over 15 dB between the DVB-H band and the communication bands (GSM, DCS, and PCS) is obtained. © 2009 Wiley Periodicals, Inc. Microwave Opt Technol Lett 51: 2196–2199, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24551</P>

An enhanced bandwidth planar inverted‐F antenna with a modified shorting strip

Park, Hoon,Jung, Heekyung,Hong, Sukjin,Choi, Jaehoon Wiley Subscription Services, Inc., A Wiley Company 2007 MICROWAVE AND OPTICAL TECHNOLOGY LETTERS Vol.49 No.3

<P><B>Abstract</B></P><P>This article presents a novel design method for a wideband planar inverted F‐antenna that simultaneously covers GSM900, GPS, DCS1800, IMT2000, WLAN, and DMB services. The proposed antenna consisted of a main patch with stubs, an I‐shaped patch, and a modified shorting strip. It had dimensions of 16 × 36 × 6 mm<SUP>3</SUP>. The dual band characteristic could be achieved by changing the length of a main patch. A very wide impedance bandwidth characteristic was obtained by optimizing the length of stubs, an I‐shaped patch, and a modified shorting strip. Commercial electromagnetic software, CST Microwave Studio, was used to design the structure. The maximum gains at the frequencies of 915, 1576, 1785, 2170, 2400, and 2630 MHz were 1.0, 2.7, 5.4, 4.56, 1.52, and 2.95 dBi, respectively. The overall radiation pattern was suitable for mobile applications. © 2007 Wiley Periodicals, Inc. Microwave Opt Technol Lett 49: 513–515, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.22179</P>

A new K-band push-push VCO using a miniaturized hairpin resonator

Lee, Hyun-Wook,Yoon, Ki-Cheol,Nam, Hee,Eo, Yun-Seong,Lee, Jong-Chul Wiley Subscription Services, Inc., A Wiley Company 2010 MICROWAVE AND OPTICAL TECHNOLOGY LETTERS Vol.52 No.3

<P>In this article, a K-band push-push Voltage Controlled Oscillator (VCO) is presented using a miniaturized hairpin resonator (MHR) with a higher loaded quality factor and the reduced circuit area within 50% compared to the conventional one at 9.2 GHz.The MHR combined with the GaAs MESFET varactor shows a tuning range of 140 MHz, and this voltage tunable MHR is used to compose a push-push VCO. It provides the frequency tuning range of 71 MHz with flatness of +0.13 dB, which is increased by 31 MHz compared to the conventional VCO. The voltage controlled push-push oscillator based on the series feedback topology is implemented on 0.54 mm-thick Teflon substrate with a dielectric constant of 2.54. The measurement shows the output power of 1.18 dBm, the fundamental signal power suppression of −33 dBc, and phase noise performance of −86.78 dBc/Hz at 100 kHz offset. © 2010 Wiley Periodicals, Inc. Microwave Opt Technol Lett 52: 699–701, 2010; Published online in Wiley InterScience (www.interscience. wiley.com). DOI 10.1002/mop.25007</P>

Pretreatment anemia is associated with poorer survival in patients with stage I and II gastric cancer

Shen, Jian Guo,Cheong, Jae Ho,Hyung, Woo Jin,Kim, Junuk,Choi, Seung Ho,Noh, Sung Hoon Wiley Subscription Services, Inc., A Wiley Company 2005 Journal of surgical oncology Vol.91 No.2

<B>Background and Objectives</B><P>A negative correlation between anemia and outcome has been demonstrated in various cancers treated with radiotherapy. However, it is rarely studied whether this correlation may exist in surgical setting. Our aim was to investigate the relationship between pretreatment anemia and survival in surgically treated patients with gastric cancer.</P><B>Methods</B><P>A total of 1,688 patients who had undergone curative resection for gastric cancer between 1991 and 1995 were reviewed. Anemia was defined as a hemoglobin level <12.0 g/dl. The influence of anemia on patient overall survival was evaluated by univariate and multivariate analysis.</P><B>Results</B><P>Pretreatment anemia was present in 39.9% of the patients. The 10-year overall survival rate in anemic patients was 48.2% as compared with 62.6% in nonanemic patients (P < 0.001). In subgroup analysis according to the stage, the significant difference in 10-year overall survival rate between anemic and nonanemic patients was found in stage I and II gastric cancer (76.1% vs. 83.5% in stage I, P = 0.030; 55.1% vs. 67.2% in stage II, P = 0.043). On multivariate analysis, anemia was an independent prognostic predictor in patients with stage I and II disease (P = 0.007; RR, 1.466; 95% CI, 1.109–1.937).</P><B>Conclusions</B><P>Pretreatment anemia was found to have an independent relationship to the long-term survival of patients with stage I and II gastric cancer. J. Surg. Oncol. 2005;91:126–130. © 2005 Wiley-Liss, Inc. J. Surg. Oncol. 2005;91:?–?. © 2005 Wiley-Liss, Inc.</P>

Analog predistortion linearization of Doherty power amplifiers using bandwidth reduction of error signal

Lee, Yong-Sub,Lee, Mun-Woo,Kam, Sang-Ho,Jeong, Yoon-Ha Wiley Subscription Services, Inc., A Wiley Company 2010 MICROWAVE AND OPTICAL TECHNOLOGY LETTERS Vol.52 No.6

<P>This article represents analog predistortion linearization of Doherty power amplifier (DPA) using bandwidth reduction of error signal. To verify our methods, two DPAs are implemented using a push-pull GaN HEMT and a push-pull Si LDMOS at 2.14 GHz and tested using the memory-compensated analog predistorter with transistor-based error generators and three-branch nonlinear paths. From the measured four-carrier WCDMA results, the proposed analog predistortion DPAs show the significant linearity improvement. © 2010 Wiley Periodicals, Inc. Microwave Opt Technol Lett 52: 1313–1316, 2010; Published online in Wiley InterScience (www.interscience. wiley.com). DOI 10.1002/mop.25190</P>

High glucose increase cell cycle regulatory proteins level of mouse embryonic stem cells via PI3-K/Akt and MAPKs signal pathways

Kim, Yun Hee,Heo, Jung Sun,Han, Ho Jae Wiley Subscription Services, Inc., A Wiley Company 2006 Journal of Cellular Physiology Vol.209 No.1

<P>This study examined the effects of high glucose on cell proliferation and its related signal pathways using mouse embryonic stem (ES) cells. Here, we showed that high glucose level significantly increased [<SUP>3</SUP>H]thymidine incorporation, BrdU incorporation, the number of cells, [<SUP>3</SUP>H]leucine, and [<SUP>3</SUP>H]proline incorporation in a time-(>3 hr) and dose-(>25 mM) dependent manner. Moreover, high glucose level increased the cellular reactive oxygen species (ROS), Akt, and mitogen-activated protein kinases (MAPKs) phosphorylation. Subsequently, these signaling molecules involved in high glucose-induced increase of [<SUP>3</SUP>H]thymidine incorporation. High glucose level also increased cyclin D1, cyclin E, cyclin-dependent kinase (CDK) 2, and CDK 4 protein levels, which is cell cycle regulatory proteins acting in G1–S phase of cell cycle. Inhibition of phosphatidylinositol 3-kinase (PI3-K) (LY 294002: PI3-kinase inhibitor, 10<SUP>−6</SUP> M), Akt (Akt inhibitor, 10<SUP>−5</SUP> M), and p44/42 MAPKs (PD 98059: MEK inhibitor, 10<SUP>−5</SUP> M) decreased these proteins. High glucose level phosphorylated the RB protein, which was decreased by inhibition of PI3-K and Akt. In conclusion, high glucose level stimulates mouse ES cell proliferation via the PI3-K/Akt and MAPKs pathways. J. Cell. Physiol. 209: 94–102, 2006. © 2006 Wiley-Liss, Inc.</P>

BRAF and KRAS mutations in prostatic adenocarcinoma

Cho, Nam-Yun,Choi, Minhee,Kim, Baek-Hee,Cho, Yong-Mee,Moon, Kyung Chul,Kang, Gyeong Hoon Wiley Subscription Services, Inc., A Wiley Company 2006 International journal of cancer: Journal internati Vol.119 No.8

<P>Constitutive activation of the kinase cascade involving RAS, RAF, MEK and ERK is common to human cancers, and mutations of KRAS and BRAF are mutually exclusive and serve as alternatives to activate the RAS/RAF/ERK signaling pathway. RAS mutations are known to occur in prostate adenocarcinomas, but little is known about BRAF mutations in these tumors. In the present study, BRAF and KRAS mutations were characterized in 206 prostate adenocarcinomas by enhanced PCR-RFLP and direct sequencing. The identified KRAS and BRAF mutations were then analyzed with respect to preoperative serum PSA levels, Gleason scores and tumor stages. Mutations in codon 600 of BRAF were identified in 21 (10.2%) of 206 prostate adenocarcinomas. KRAS mutations in codons 12 or 13 were found in 15 (7.3%) of 206 prostate adenocarcinomas. However, no tumor specimen contained both BRAF and KRAS mutations. Prostate adenocarcinomas with a BRAF mutation tended to show higher preoperative serum PSA levels, Gleason scores and tumor stages than prostate adenocarcinomas with a KRAS mutation. The results obtained show that BRAF mutations are as uncommon as KRAS mutations in prostate adenocarcinoma. Although BRAF and KRAS are members of the same RAS/ERK signaling pathway, prostate adenocarcinomas with a BRAF mutation showed clinicopathologic features that differed from those of prostate adenocarcinoma with a KRAS mutation. © 2006 Wiley-Liss, Inc.</P>

Prediction of protein secondary structure content using amino acid composition and evolutionary information

Lee, Soyoung,Lee, Byung-chul,Kim, Dongsup Wiley Subscription Services, Inc., A Wiley Company 2006 Proteins Vol.62 No.4

<P>Knowing protein structure and inferring its function from the structure are one of the main issues of computational structural biology, and often the first step is studying protein secondary structure. There have been many attempts to predict protein secondary structure contents. Previous attempts assumed that the content of protein secondary structure can be predicted successfully using the information on the amino acid composition of a protein. Recent methods achieved remarkable prediction accuracy by using the expanded composition information. The overall average error of the most successful method is 3.4%. Here, we demonstrate that even if we only use the simple amino acid composition information alone, it is possible to improve the prediction accuracy significantly if the evolutionary information is included. The idea is motivated by the observation that evolutionarily related proteins share the similar structure. After calculating the homolog-averaged amino acid composition of a protein, which can be easily obtained from the multiple sequence alignment by running PSI-BLAST, those 20 numbers are learned by a multiple linear regression, an artificial neural network and a support vector regression. The overall average error of method by a support vector regression is 3.3%. It is remarkable that we obtain the comparable accuracy without utilizing the expanded composition information such as pair-coupled amino acid composition. This work again demonstrates that the amino acid composition is a fundamental characteristic of a protein. It is anticipated that our novel idea can be applied to many areas of protein bioinformatics where the amino acid composition information is utilized, such as subcellular localization prediction, enzyme subclass prediction, domain boundary prediction, signal sequence prediction, and prediction of unfolded segment in a protein sequence, to name a few. Proteins 2006. © 2005 Wiley-Liss, Inc.</P>