bluuebunny/crossref_metadata_2025 huggingface dataset:
Breast carcinomas with strong high‐signal intensity on T2‐weighted MR images: Pathological characteristics and differential diagnosis
Authors: Yuen Sachiko , Uematsu Takayoshi , Kasami Masako , Tanaka Kumiko , Kimura Kiyomi , Sanuki Junichi , Uchida Yoshihiro , Furukawa Hiroyoshi
Published: February 2007

Purpose

To investigate the histopathological characteristics of breast carcinomas with strong high‐signal intensity (SHi) on T2‐weighted (T2W) MR images (T2‐SHi), and discuss the differential diagnosis between T2‐SHi breast carcinomas and T2‐SHi fibroadenomas.

Materials and Methods

Thirty of 480 breast carcinomas examined by MRI were defined as tumors with T2‐SHi (defined as homogeneous higher signal intensity (SI) compared to surrounding normal breast tissue on fat‐suppressed T2W imaging (T2WI). They included eight mucinous and 22 nonmucinous carcinomas. The histopathological characteristics of T2‐SHi breast carcinomas, their signal‐to‐noise ratios (SNRs) on T2WI, contrast‐enhancement patterns, and morphology were compared with those of 22 non‐T2‐SHi breast carcinomas and 19 T2‐SHi fibroadenomas.

Results

In nonmucinous carcinomas T2‐SHi was attributable to a mixture of background matrix, a higher proportion of cells than stroma, abundant cytoplasm, edematous stroma, and hemorrhage. The significantly high SNR (mean = 75) and enhancing internal septations seen in mucinous carcinomas, and the washout phenomenon, irregular border, absence of internal septation, and rim enhancement seen in nonmucinous carcinomas provide useful information for differentiating these tumors from T2‐SHi fibroadenomas.

Conclusion

A mixture of several histopathological characteristics was associated with T2‐SHi breast carcinomas. The combined information from T2WI and contrast‐enhanced (CE) imaging may help distinguish T2‐SHi breast carcinomas from T2‐SHi fibroadenomas. J. Magn. Reson. Imaging 2007;25:502–510. © 2007 Wiley‐Liss, Inc.
Contrast‐enhanced FLAIR imaging in combination with pre‐ and postcontrast magnetization transfer T1‐weighted imaging: Usefulness in the evaluation of brain metastases
Authors: Terae Satoshi , Yoshida Daisuke , Kudo Kohsuke , Tha Khin Khin , Fujino Masaharu , Miyasaka Kazuo
Published: February 2007

Purpose

To assess whether the use of postcontrast fluid‐attenuated inversion recovery (FLAIR) imaging in combination with pre‐ and postcontrast magnetization transfer (MT) T1‐weighted imaging (T1WI) can increase diagnostic confidence in the evaluation of brain metastases.

Materials and Methods

Brain MR images from 41 patients with suspected brain metastases were reviewed. Two radiologists viewed pre‐ and postcontrast MT‐T1W images for the presence of metastatic tumors and rated the possible enhanced lesions using a five‐point confidence scale (session 1). The postcontrast FLAIR images were then viewed together with pre‐ and postcontrast MT‐T1W images, and the presence of metastasis was rated again (session 2).

Results

A total of 240 possible enhanced lesions were detected in session 1. Judging by follow‐up MR examinations, 196 were considered to be nonmetastatic findings and 44 were determined to be metastasis. In session 2 the confidence rating for nonmetastasis increased significantly in the subset of nonmetastatic findings (P < 0.001), and the confidence rating for metastasis increased significantly in the subset of metastases (P < 0.05).

Conclusion

The addition of postcontrast FLAIR imaging to pre‐ and postcontrast MT‐T1WI improves diagnostic confidence in evaluation of brain metastases. J. Magn. Reson. Imaging 2007;25:479–487. © 2007 Wiley‐Liss, Inc.
Detection and validated quantification of toxic alkaloids in human blood plasma—comparison of LC‐APCI‐MS with LC‐ESI‐MS/MS
Authors: Beyer Jochen , Peters Frank T. , Kraemer Thomas , Maurer Hans H.
Published: February 2007

Poisonings with toxic plants may occur after abuse, intentional or accidental ingestion of plants. For diagnosis of such poisonings, multianalyte procedures were developed for detection and validated quantification of the toxic alkaloids aconitine, atropine, colchicine, coniine, cytisine, nicotine and its metabolite cotinine, physostigmine, and scopolamine in plasma using LC‐APCI‐MS and LC‐ESI‐MS/MS. After mixed‐mode solid‐phase extraction of 1 ml of plasma, the analytes were separated using a C8 base select separation column and gradient elution (acetonitrile/ammonium formate, pH 3.5). Calibration curves were used for quantification with cotinine‐d3, benzoylecgonine‐d3, and trimipramine‐d3 as internal standards. The method was validated according to international guidelines. Both assays were selective for the tested compounds. No instability was observed after repeated freezing and thawing or in processed samples. The assays were linear for coniine, cytisine, nicotine and its metabolite cotinine, from 50 to 1000 ng/ml using LC‐APCI‐MS and 1 to 1000 ng/ml using LC‐ESI‐MS/MS, respectively, and for aconitine, atropine, colchicine, physostigmine, and scopolamine from 5 to 100 ng/ml for LC‐APCI‐MS and 0.1 to 100 ng/ml for LC‐ESI‐MS/MS, respectively. Accuracy ranged from − 38.6 to 14.0%, repeatability from 2.5 to 13.5%, and intermediate precision from 4.8 to 13.5% using LC‐APCI‐MS and from − 38.3 to 8.3% for accuracy, from 3.5 to 13.8%, for repeatability, and from 4.3 to 14.7% for intermediate precision using LC‐ESI‐MS/MS. The lower limit of quantification was fixed at the lowest calibrator in the linearity experiments. With the exception of the greater sensitivity and higher identification power, LC‐ESI‐MS/MS had no major advantages over LC‐APCI‐MS. Both presented assays were applicable for sensitive detection of all studied analytes and for accurate and precise quantification, with the exception of the rather volatile nicotine. The applicability of the assays was demonstrated by analysis of plasma samples from suspected poisoning cases. Copyright © 2007 John Wiley & Sons, Ltd.
Stabilization of astaxanthin in edible oils and its use as an antioxidant
Authors: Rao Ambati Ranga , Sarada Ravi , Ravishankar Gokare Aswathanarayana
Published: February 2007

Astaxanthin, a ketocarotenoid (3,3′‐dihydroxy‐β,β‐carotene‐4,4′‐dione), is produced in high concentration in the green alga Haematococcus pluvialis. It constitutes 85–88% of total carotenoid and exists in the monoester, diester and free form. Astaxanthin in its ester form is fairly stable in all edible oils such as rice bran, mustard, groundnut, gingelly, coconut and palm oil at room temperature with variation in terms of its loss in content and colour during a 4 month period. Rice bran, gingelly and palm oil retained 84–90% of astaxanthin when heated at 70 °C for 8 h while palm oil was effective in retaining 90% of astaxanthin at 90 °C for 8 h without any change in its ester form in comparison to 90% carotenoid loss in aqueous form. At 120 and 150 °C, carotenoid loss was significant (60–90%) without change in the fatty acid profile of the edible oils. The antioxidant activity of carotenoids stored in oils was comparable to standard butylated hydroxy anisole (BHA). Copyright © 2007 Society of Chemical Industry
The effect of sample grinding procedures after processing on gas production profiles and end‐product formation in expander processed barley and peas
Authors: Azarfar Arash , van der Poel Antonius F. B. , Tamminga Seerp
Published: February 2007

Grinding is a technological process widely applied in the feed manufacturing industry and is a prerequisite for obtaining representative samples for laboratory procedures (e.g. gas production analysis). When feeds are subjected to technological processes other than grinding (e.g. expander treatment), grinding afterwards may disturb the effect of processing, both in practice and when laboratory techniques are applied. Therefore, this study aimed to establish the possible effects of different grinding procedures and sample preparation on the degradative behaviour of expander processed barley and peas. Samples of expander processed barley and peas were subjected to six different sample preparation procedures (intact sample, dissolved sample, samples ground stepwise over 6 and 3 mm sieves, samples ground stepwise over 6, 3 and 1 mm sieves, samples ground over a 3 mm sieve and samples ground over a 1 mm sieve). The patterns of gas production in these samples were studied over a period of 72 h incubation using an automated in vitro gas production system. The particle size distribution determined by dry sieve analysis and the Coulter counter method changed due to the different grinding procedures. Grinding the samples of expander processed barley and peas changed the kinetics of gas production and led to a faster degradation, most pronounced after stepwise grinding. However, the formation of the fermentation end‐product was not affected by the method of sample preparation. In expander processed barley, the difference in the degradation pattern due to the different grinding procedures was small. Copyright © 2007 Society of Chemical Industry
Integral utilisation of barley husk for the production of food additives
Authors: Cruz José M , Moldes Ana B , Bustos Guadalupe , Torrado Ana , Domínguez José M
Published: February 2007

A new and effective chemical–biotechnological process for the global utilisation of barley husk (obtained from the spent grains in the brewing process) is reported. With the proposed process the three main components of the lignocellulosic residue (cellulose, hemicellulose and lignin) are utilised. A first treatment with sulfuric acid (pre‐hydrolysis) allowed the solubilisation of hemicelluloses to give xylose and glucose‐containing liquors (suitable to make fermentation media for the continuous lactic acid (LA) production with L. pentosus) and a solid phase containing cellulose and lignin. In this set of experiments, a maximum volumetric productivity (QP) = 2.077 g L−1 h−1 and product yield (YP/S) = 0.62 g g−1 were obtained for a dilution rate of 0.01 h−1. The solid residues from pre‐hydrolysis were treated with NaOH in order to increase their cellulase digestibility, and dissolve the lignin content. The cellulose residue was used as substrates for lactic acid production by simultaneous saccharification and fermentation (SSF) in media containing Trichoderma reesei cellulases and Lactobacillus rhamnosus cells using the complete MRS broth or a cheaper medium. In both cases similar LA concentrations and volumetric productivities were achieved (P = 73.4–71.0 g L−1 and QP = 1.28–1.25 g L−1 h−1, respectively), where P is LA concentration. The lignin solution obtained after the alkaline treatment was extracted with ethyl acetate in order to obtain the phenolic components. The extract obtained at pH 3 showed three times more antioxidant activity than the one extracted at pH 12.8, with an EC50 of 1.396 g L−1 for pH 3 and 4.604 g L−1 for pH 12.8. The best extracts showed twice antioxidant activity than BHT. Copyright © 2007 Society of Chemical Industry
Dietetic and hypocholesterolaemic action of black soy peptide in dietary obese rats
Authors: Rho Shin Joung , Park Soojin , Ahn Chang‐Won , Shin Jae‐Kil , Lee Hyeon Gyu
Published: February 2007

To investigate the effect of peptides from black soy (rat's eye) bean (Rhynchosia volubilis Lour.) on weight gain and lipid composition, Sprague–Dawley male rats were fed either a black soy peptide (BSP; 2, 6 or 10% of energy)‐containing diet or a casein control diet (20% of energy) enriched with 36% fat and 1% cholesterol for 28 days. Compared with the casein group, the BSP groups showed significant attenuation of body, liver and epididymal adipose tissue weight gains (P < 0.05). Moreover, rats that consumed BSP had a lower total cholesterol concentration and low‐density lipoprotein/high‐density lipoprotein (LDL/HDL) ratio in serum and a lower level of hepatic triglycerides as well as higher excretion of faeces compared with those fed only casein (P < 0.05). Molecular weights of peptides from black soy were mainly below 10 kDa, and Arg/Lys and Gly/Met ratios in BSP were five and three times of those in casein respectively. It is concluded that BSP can be a potent nutraceutical component for anti‐obesity and hypolipidaemic benefits. Copyright © 2007 Society of Chemical Industry
Clinicopathologic features of poorly differentiated hepatocellular carcinoma
Authors: Oishi Koichi , Itamoto Toshiyuki , Amano Hironobu , Fukuda Saburo , Ohdan Hideki , Tashiro Hirotaka , Shimamoto Fumio , Asahara Toshimasa
Published: February 2007

Background and Objectives

Clinicopathologic features of poorly differentiated hepatocellular carcinoma (HCC) have not been elucidated. The purpose of this study was to clarify the characteristics of poorly differentiated HCC in hepatectomized patients.

Methods

From 1986 to 2001, 354 HCC patients underwent curative hepatectomy in our institution and were prospectively followed. Histological examinations revealed 43 well‐differentiated HCC tumors, 273 moderately differentiated HCC tumors, and 38 poorly differentiated HCC tumors. Clinicopathologic factors and outcomes after hepatectomy were compared statistically.

Results

Only serum alpha‐fetoprotein level was significantly different in the poorly differentiated HCC group from that in the moderately differentiated HCC group preoperatively (P = 0.0001). Although there were no significant differences between overall survival rates or between disease‐free survival rates in the three groups, distant metastasis within 2 years after hepatectomy occurred more frequently in the poorly differentiated HCC group (21%) than in the well‐differentiated HCC group (2%) (P = 0.011) or moderately differentiated HCC group (8%) (P = 0.018). Distant metastasis occurred in about 40% of patients in the poorly differentiated HCC group with tumor size greater than 3 cm.

Conclusions

Poorly differentiated HCC tumors larger than 3 cm are already of advanced stage representing distant metastasis in the early period after hepatectomy. J. Surg. Oncol. 2007;95:311–316. © 2007 Wiley‐Liss, Inc.
Factors influencing recurrence after curative resection for ampulla of vater carcinoma
Authors: Park Joon Seong , Yoon Dong Sup , Kim Kyung Sik , Choi Jin Sub , Lee Woo Jung , Chi Hoon Sang , Kim Byong Ro
Published: February 2007

Background

Carcinoma of the ampulla of Vater has a relatively higher resection rate, lower recurrence rate, and more favorable prognosis than other malignant tumors of the periampullary region. Because of the relative low incidence of carcinoma of the ampulla of Vater, there have been few reports on the patterns and risk factors of recurrence after curative resection. The aim of this study was to evaluate the patterns and risk factors of recurrence after curative resection of ampulla of Vater carcinoma.

Materials and Methods

Between January 1992 and December 2002, 102 patients received radical resection for ampulla of Vater carcinoma at Yonsei University Medical Center. Fifteen patients were excluded because of incomplete clinicopathologic data. Finally, 87 patients were reviewed and analyzed to assess predictors of tumor recurrence.

Results

Among the 87 patients, 37 patients (42.5%) experienced recurrent disease. The mean length of time to recurrence was 29.3 ± 35.3 months, and the most common sites of recurrence were the intra‐abdominal organs: liver and loco‐regional lymph nodes. The patients were divided into two groups: early recurrence (≤18 months) and late recurrence (>18 months). In the early recurrence group, ulcer formation tumors and poorly differentiated tumors were more common in comparison with the late recurrence group. Lymph node metastasis was identified as an independent factor of tumor recurrence after curative resection for ampulla of Vater carcinoma.

Conclusion

Lymph node metastasis is the most important risk factor for recurrence after a curative resection. Also, the fact that a higher probability of recurrence is anticipated in cases of ulcer formation and poorly differentiated tumors, there exists a need for a close‐up follow‐up program. J. Surg. Oncol. 2007;95:286–290. © 2006 Wiley‐Liss, Inc.
Adefovir Dipivoxil for Wait-Listed and Post–Liver Transplantation Patients with Lamivudine-Resistant Hepatitis B
Authors: Schiff Eugene , Lai Ching-Lung , Hadziyannis Stephanos , Neuhaus Peter , Terrault Norah , Colombo Massimo , Tillmann Hans , Samuel Didier , Zeuzem Stefan , Villeneuve Jean-Pierre , Arterburn Sarah , Borroto-Esoda Katyna , Brosgart Carol , Chuck Steven
Published: February 2007

Wait-listed (n = 226) or post–liver transplantation (n = 241) chronic hepatitis B (CHB) patients with lamivudine-resistant hepatitis B virus (HBV) were treated with adefovir dipivoxil for a median of 39 and 99 weeks, respectively. Among wait-listed patients, serum HBV DNA levels became undetectable (<1,000 copies/mL) in 59% and 65% at weeks 48 and 96, respectively. After 48 weeks, alanine aminotransferase (ALT), albumin, bilirubin, and prothrombin time normalized in 77%, 76%, 60%, and 84% of wait-listed patients, respectively. Among posttransplantation patients, serum HBV DNA levels became undetectable in 40% and 65% at weeks 48 and 96, respectively. After 48 weeks, ALT, albumin, bilirubin, and prothrombin time normalized in 51%, 81%, 76%, and 56% of posttransplantation patients, respectively. Among wait-listed patients who underwent on-study liver transplantation, protection from graft reinfection over a median of 35 weeks was similar among patients who did (n = 34) or did not (n = 23) receive hepatitis B immunoglobulin (HBIg). Hepatitis B surface antigen was detected on the first measurement only in 6% and 9% of patients who did or did not receive HBIg, respectively. Serum HBV DNA was detected on consecutive visits in 6% and 0% of patients who did or did not receive HBIg, respectively. Treatment-related adverse events led to discontinuation of adefovir dipivoxil in 4% of patients. Cumulative probabilities of resistance were 0%, 2%, and 2% at weeks 48, 96, and 144, respectively. In conclusion, adefovir dipivoxil is effective and safe in wait-listed or posttransplantation CHB patients with lamivudine-resistant HBV and prevents graft reinfection with or without HBIg. Liver Transpl 13:349-360, 2007. © 2007 AASLD.
Simulation of Styrene Polymerization by Monomolecular and Bimolecular Nitroxide‐Mediated Radical Processes over a Range of Reaction Conditions
Authors: Belincanta‐Ximenes Juliana , Mesa Paola V. R. , Lona Liliane M. F. , Vivaldo‐Lima Eduardo , McManus Neil T. , Penlidis Alexander
Published: February 2007

Simulations of polymerization rate, molecular weight development and evolution of the concentrations of species participating in the reaction mechanism over a range of operating conditions, and a parameter sensitivity analysis showing the effects of temperature, activation/deactivation equilibrium constant and initial concentrations of controller and initiator (if present) on these variables are presented for the nitroxide‐mediated radical polymerization of styrene. The simulations were performed with a computer program based on a detailed reaction mechanism. The simulated profiles of conversion, number average molecular weight ($\overline M _{\rm n}$), and polydispersity agree well with experimental data. Previously unknown activation energies for reactions involved in the mechanism are estimated. The temperature dependence of the kinetic rate constants obtained in this study will be useful for future modeling and optimization studies.

magnified image
Monte Carlo Simulation of ABA Triblock Copolymer Melts Confined in a Cylindrical Nanotube
Authors: Xiao Xingqing , Huang Yongmin , Liu Honglai , Hu Ying
Published: February 2007

Monte Carlo simulations were used to identify the microphase morphologies of ABA triblock copolymer melts confined in a cylindrical nanotube. The influences of the volume fraction of mid‐block B (fB), the radius of nanotube (R) and the asymmetry of ABA triblock copolymer chain were discussed in detail. When fB varies, a series of double‐continuous, three‐layer concentric cylinder barrel, porous net, double helixes and the new multiplex structures were observed under different conditions. In addition, the stacked disk, catenoid‐cylinder and multi‐layer concentric cylinder barrel structures occur in turns at changing R. The relation between circular lamellae period L and layer number Nlayer of concentric cylinder barrel with the increase of R was investigated to further explain the put‐off phenomenon of microphase transition of the multi‐layer concentric cylinder barrel structures. As for the increase of the asymmetry of ABA triblock copolymer chain, it was concluded that the short AI segments tend to site at the interface between rich A and B circular lamellae.

magnified image
Studies of Adjacent Re‐Entry Folds of Chains of Syndiotactic l,2‐Poly(1,3‐butadiene) by Molecular Mechanics Calculations
Authors: Napolitano Roberto , Pirozzi Beniamino
Published: February 2007

The mode of packing and the adjacent re‐entry folds of chains of syndiotactic 1,2‐poly(1,3‐butadiene) have been studied by molecular mechanics calculations with the use of various sets of potential functions. The results of the packing analysis indicate that the crystal grows preferentially along the [100] and [110] directions. Models of fold have been built up on an infinite ab surface completely covered by adjacent re‐entry folds in the (100) and (110) planes. The results of energy minimizations show that several almost isoenergetic folds, constituted by four monomeric units, can be realized in the (100) planes, while the fold in the (110) planes has higher energy. The calculated value of the work of fold is in satisfactory agreement with that derived by crystallization kinetics reported in literature.

magnified image
Matrix Representation of Polymer Chain Size Distributions, 2
Authors: Sanches Heloísa L. , Melo Príamo A. , Pinto José Carlos
Published: February 2007

Analysis of the mass balance equations that describe a reaction system may be useful to provide information about its dynamics, such as the restricted set of compositions that can be achieved from a given set of initial compositions and the effect of feeding reactants to the reaction environment along the reaction course. Since these results may be important for the formulation of reaction policies, this work presents the properties of a matrix polymerization model previously developed and extended to describe transient conditions. This model is based on the definitions of two matrices: the consumption matrix (A − Kt), which contains information about chemical transformations among the many active polymer species in the system, and the propagation matrix Kp, which contains information about chain growth. It is shown that the set of mass balance equations that describes the dynamics of active chemical species in polymerization reactions has a stable and unique solution, which is bounded if feed rates are also bounded. It is also shown that the set of compositions that may be reached through manipulation of the feed rates is restricted and may not include all possible chemical compositions. Finally, it is shown that the obtained molecular weight distributions are special multiple time convolutions of the initiation rates.

magnified image
The strategic use of managerial incentives in a non‐profit firm mixed duopoly
Authors: Goering Gregory E.
Published: February 2007

A mixed duopoly setting is examined where a private non‐profit firm (NPO) competes with a private profit‐maximizer. The NPO's stakeholders select a contract for their managers. A novel NPO objective function is utilized which takes into account all the likely returns to the NPO's stakeholders (NPO profits and the surplus accruing to the NPO stakeholders) in such a commercial setting. In sub‐game perfect equilibria, it is shown that the NPO's managers generally will not be given the NPO's true objective to optimize. It is also shown that aggregate social welfare may increase or decrease due to this managerial contracting behavior or the use of NPO membership fees. Copyright © 2007 John Wiley & Sons, Ltd.
If you play well they will come—and vice versa: bidirectional causality in major‐league baseball
Authors: Horowitz Ira
Published: February 2007

The Granger‐causality test is applied to the annual attendance and win‐percentage data for 29 major‐league teams. It is shown that bidirectional causality exists for these teams and that there are some essential differences between the original 10 of 16 franchises that comprised the majors in 1903 and the six that relocated between 1953 and 1961. Some differences and some similarities are also seen in the parameter estimates for both blocs of teams, the relocated teams, and seven long‐lived expansion franchises. Finally, the parameter estimates are manipulated to yield noise‐free equilibrium estimates for both attendance and performance. In tandem, these two sets of estimates provide fodder for speculation as to the futures of each of the extant 23 franchises considered here. Copyright © 2007 John Wiley & Sons, Ltd.
A further clarification of OCRA and its properties in response to Wang and Wang (2005)
Authors: Parkan Celik
Published: February 2007

This is an exposition written in response to the claims in Wang and Wang (2005) about the problems with the method of OCRA, operational competitiveness rating analysis, for gauging the relative performances of a set of operating entities. Copyright © 2007 John Wiley & Sons, Ltd.
Tri‐section stepped‐impedance bandpass filter with wide stopband performance
Authors: Wang Yunxiu , Wang Bing‐Zhong , Wang Jianpeng , Gao Shanshan , Xiao Shaoqiu
Published: February 2007

In this paper, a compact microstrip bandpass filter with wide stopband performance is presented. Wide stopband performance is achieved by introducing both stepped‐impedance resonator and over‐coupling technique. With the new structure, the filter has not only wide upper stopband performance with harmonic frequency outside 5f0but also compact size. © 2007 Wiley Periodicals, Inc. Microwave Opt Technol Lett 49: 870–872, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI.10.1002/mop.22255
C‐band fully integrated SiGe HBT superharmonic QVCO
Authors: Tseng S. C. , Meng C. C. , Chang Y. W. , Huang G. W.
Published: February 2007

This paper demonstrates a 4‐GHz monolithic SiGe heterojunction bipolar transistor quadrature voltage‐controlled oscillator (QVCO) using superharmonic coupling topology. The QVCO at 4.17 GHz has phase noise of −116 dBc/Hz at 1 MHz offset frequency, output power of −6 dBm, and the figure of merit −179 dBc/Hz. The core current consumption is 3.2 mA at 3 V supply voltage. The die size is about 1.4 mm × 1.2 mm. © 2007 Wiley Periodicals, Inc. Microwave Opt Technol Lett 49: 867–869, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI.10.1002/mop.22256
Shaped beam printed antenna with waveguide power divider for synthetic aperture radar applications
Authors: Sharma S. B. , Kulshrestha Sanjeev , Pandey B. K. , Sharma D. K. , Jyoti Rajeev , Chakrabarty S. B.
Published: February 2007

This paper presents design and development of X band 8 × 32 element planar array, with center frequency at 9.65 GHz. Stacked microstrip patch antenna where the lower patch is directly fed by microstrip line has been used as a single radiating element. The complex excitation coefficients have been computed using null perturbation technique, so as to provide shaped beam pattern in elevation plane and pencil beam pattern in the azimuth plane. Eight elements have been used to form shaped pattern. Different sets of coefficients were computed. The set of excitation coefficient that results in minimum current taper ratio has been selected to realize the antenna. H plane septum power divider has been used for high‐power requirement, along with tapered transition from waveguide to microstrip. The simulated and measured data on return loss and radiation patterns have been presented. © 2007 Wiley Periodicals, Inc. Microwave Opt Technol Lett 49: 832–835, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.22257
Multicenter perfectly matched layer implementation for finite element mesh truncation
Authors: Ozgun Ozlem , Kuzuoglu Mustafa
Published: February 2007

We present the multicenter perfectly matched layer (PML) technique, which is an easy and practical conformal PML implementation, obtained by the complex coordinate stretching, to the problem of mesh truncation in the finite element method. After developing the analytical background of this method, we demonstrate its performance in electromagnetic radiation/scattering problems. © 2007 Wiley Periodicals, Inc. Microwave Opt Technol Lett 49: 827–832, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.22258
A simple method to design a compact and high performance wideband filter
Authors: Hung Cheng‐Yuan , Weng Min‐Hang , Su Yan‐Kuin , Yang Ru‐Yuan
Published: February 2007

In this letter, a simple method to design a compact and high performance dual hooks wideband filter with open stubs is presented. By combining the coupled line section with two tapped open stubs, a wideband filter with wide stopband and very high passband selectivity is realized. This filter at center frequency f0 of 5.3 GHz has presented very good measured characteristics, including 3‐dB fractional bandwidth of 85%, very low insertion loss of −0.5 ± 0.3 dB, wide stopband from 8 to 15 GHz, and very high selectivity near the passband edge. © 2007 Wiley Periodicals, Inc. Microwave Opt Technol Lett 49: 822–824, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.22268
Generation of dark RZ signals by using one delayed line Mach‐Zehnder interferometer along with one phase modulator
Authors: Shao Yufeng , Chen Lin , Wen Shuangchun
Published: February 2007

We propose and experimentally demonstrate a simple and novel optical transmitter for 10‐Gbit/s dark RZ signals. The proposed transmitter comprises a phase modulator and a delayed line Mach‐Zehnder (DL‐MZ) interferometer. Different duty cycle and extinction ratio of dark RZ signals can be generated by adjusting the time delayed line of the DL‐MZ interferometer. Dark RZ signals show higher optical spectra efficiency. © 2007 Wiley Periodicals, Inc. Microwave Opt Technol Lett 49: 755–759, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.22272
Tunable erbium‐doped fiber ring laser based on coupling between side‐polished fiber and sliding tapered planar waveguide
Authors: Lee Dong‐Ho , Kwon Kwang‐Hee , Song Jae‐Won , Kim Kwang‐Taek
Published: February 2007

A tunable erbium‐doped fiber ring laser was made using a tunable side‐polished fiber (SPF) filter with a tapered planar waveguide (PWG). The thickness of the tapered PWG varied because it slides laterally on the side‐polished region. The proposed SPF filter does not need additional physical energy after resonant wavelength selected. Tuning direction of SPF filter is not limited. In addition, the proposed SPF filter can change the tuning resolution by changing the tapered angle of PWG. © 2007 Wiley Periodicals, Inc. Microwave Opt Technol Lett 49: 887–889, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.22273
A closed‐form solution to the asymptotic part of the MOM impedance matrix and the MOM excitation vector for printed structures on planar grounded dielectric slabs
Authors: Bakýr O. , Ertürk V. B.
Published: February 2007

In the spectral domain method of moments (MoM) solution of printed structures on planar grounded dielectric slabs, the infinite double integrals which appear in the asymptotic parts of the MoM impedance matrix and the MoM excitation vector elements, have been previously transformed to one‐dimensional finite integrals, which have been numerically computed using the highly specialized “International Mathematics and Statistics Library” subroutines. In this paper, these one‐dimensional integrals are evaluated in closed‐form, resulting in an improved efficiency and accuracy for the rigorous investigation of printed antennas and complex millimeter and microwave integrated circuits. Numerical results in the form of mutual impedance between two expansion functions and input impedance of various microstrip antennas are presented to assess the accuracy of these closed‐form expressions. © 2007 Wiley Periodicals, Inc. Microwave Opt Technol Lett 49: 882–886, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.22274
Noise modeling of heterojunction bipolar transistors using neural network approach
Authors: Marković V. , Prasad S. , Stoǐć A.
Published: February 2007

The advantages of heterojunction bipolar transistors (HBTs) make them very promising for modern RF communication systems and therefore their noise performance becomes an important issue as well. A procedure for HBT noise modeling based on the neural network approach is presented in this paper. The proposed models are characterized by high accuracy and efficiency commonly requested for today's CAD techniques. © 2007 Wiley Periodicals, Inc. Microwave Opt Technol Lett 49: 852–854, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI.10.1002/mop.22275
Expressions of radiation field and input resonance resistance of coaxial and microstrip line fed rectangular microstrip antennas
Authors: Şimşek Serkan , Işık Cevdet , Tezel Necmi Serkan , Akkaya İnci
Published: February 2007

In this paper, the radiation field of a rectangular microstrip antenna is calculated considering four edges of the antenna. The present method is based on expressing the radiated field, the radiation power, and the power losses in terms of the feeding voltage, and then developing an expression for the input resonance resistance of the antenna at resonance. © 2007 Wiley Periodicals, Inc. Microwave Opt Technol Lett 49: 817–822, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.22277
Wideband and low noise CMOS amplifier for UWB receivers
Authors: Jung Jihak , Yun Taeyeoul , Choi Jaehoon , Kim Hoontae
Published: February 2007

An ultra‐wideband (UWB) low noise amplifier (LNA) that consists of two common‐source and shunt‐feedback stages is presented. Measurement results show the maximum gain (S21) of 13.5 dB with the 3‐dB band from 1.85 to 10.2 GHz and return losses (S11, S22) of less than −10 dB from 3 to 11 GHz. In addition, the fabricated LNA achieves the average noise figure (NF) of 4.5 dB from 1.85 to 10.2 GHz. To our knowledge, these are the best measured data up to date for the CMOS LNA. The input‐referred third‐order intercept point (IIP3) and the input‐referred 1‐dB compression point (P1dB) are obtained as −1 dBm and −9 dBm, respectively, while consuming 13 mW in 0.18 μm RF CMOS process. © 2007 Wiley Periodicals, Inc. Microwave Opt Technol Lett 49: 749–752, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.22282
Design and implementation of a 1.5‐ to 17‐GHz SiGe UWB LNA utilizing multiple‐feedback loops and inductive peaking technique
Authors: Yen Shu‐Hui , Lin Yo‐Sheng , Chen Chi‐Chen
Published: February 2007

In this paper, we demonstrate a 1.5‐ to 17‐GHz ultra‐wideband (UWB) low‐noise amplifier (LNA) with small‐inductance input inductor and multiple‐feedback loops implemented in a 0.35 μm SiGe BiCMOS technology. A method named inductive peaking, which adds an inductor in series with the base‐terminal of the second‐stage amplifier to enhance the frequency of the dominant pole, was adopted to improve gain and bandwidth of the LNA. The measurement results show that very flat gain (S21) of 8 ± 0.5 dB was achieved for frequencies between 2 and 15 GHz. In addition, reverse isolation (S12) lower than −27 dB, input return loss (S11) and output return loss (S22lower than −9 dB, and noise figure lower than 5.5 dB was achieved in the 3.1–10.6 GHz UWB band. The chip area was 775 × 710 μm2, excluding the test pads. This LNA drains 7 mA current at supply voltage of 3 V, i.e. it only consumes 21 mW power. © 2007 Wiley Periodicals, Inc. Microwave Opt Technol Lett 49: 876–879, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI.10.1002/mop.22284
Photo‐induced millimeter wave losses in coplanar waveguide on high resistivity silicon
Authors: Poesen G. , Koers G. , Stiens J. , Carchon G. , De Raedt W. , Vounckx R.
Published: February 2007

We report on a multifunctional optoelectronic radio frequency attenuator for millimeter wave applications, designed in a multilayer thin‐film multichip module technology on high resistive silicon. Insertion loss of measurements and electromagnetic simulations of a coplanar waveguide line under illumination demonstrate a contrast of 40 dB at 100 GHz. © 2007 Wiley Periodicals, Inc. Microwave Opt Technol Lett 49: 808–810, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.22288
Photonic crystal optical fibers for dispersion compensation and Raman amplification: Design and experiment
Authors: Digweed‐Lyytikainen K. , De Francisco C. A. , Spadoti D. , Juriollo A. A. , Rosolem J. B. , Ayres Neto J. B. M. , Borges B. V. , Canning J. , Romero M. A.
Published: February 2007

An optimal design of photonic crystal optical fibers for simultaneous dispersion compensation and Raman amplification is investigated by numerical simulation using the finite‐difference simultaneous over‐relaxation method. The proposed fiber was fabricated and experimental characterization results are presented. © 2007 Wiley Periodicals, Inc. Microwave Opt Technol Lett 49: 872–874, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI.10.1002/mop.22294
An explicit fourth‐order accurate FDTD method based on the staggered ADAMS‐bashforth time integrator
Authors: Xiao Fei , Tang Xiaohong , Wang Ling
Published: February 2007

This article presents an explicit fourth‐order accurate Finite Difference Time Domain (FDTD) method, in which the fourth‐order accurate staggered Adams‐Bashforth time integrator is used for temporal discretization and the fourth‐order accurate Taylor Central Finite Difference scheme for spatial discretization. The analysis shows that the numerical dispersion of the new FDTD method is much lower than that of the Fang‐FDTD method and the stability restraint of the new FDTD methods is relaxed in comparison with that of the FDTD method using the Staggered Backward Differentiation time integrator. © 2007 Wiley Periodicals, Inc. Microwave Opt Technol Lett 49: 910–912, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.22303
A valid and convenient method of using mode charts and quality factor charts in DR cavity filter designs
Authors: Sun Xiaoguang
Published: February 2007

Mode charts and Quality factor charts are computed using the mode matching method in the article. To get accurate Q factors, perturbation theory is applied. Using the charts, a six‐cavity DR filter is designed and fabricated. And the validity of the method is verified by experiment. © 2007 Wiley Periodicals, Inc. Microwave Opt Technol Lett 49: 960–963, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.22310
Study of ground plane of dual‐band patch antenna on SAR
Authors: Chan K. H. , Tang C. K. , Wong K. H. , Fung L. C. , Leung S. W.
Published: February 2007

This paper investigates the effects of different ground plane configurations of a typical GSM900/1800 dual‐band internal planar inverted‐F patch antenna (PIFA) on specific absorption rate (SAR) and corresponding antenna performance. The effect of the length and width of the ground plane and the addition of vertical sidewall on the ground plane are presented. Results have shown that when the length and width of the antenna ground plane is increased, the SAR value could be reduced while radiation efficiency is not significantly affected, the antenna gain is reduced by 3.5 dB at 930 MHz, and the envelope of far‐field antenna pattern is mainly affected in the human head direction. The addition of vertical sidewall at four sides of the ground plane with a height of 7 mm could provide a SAR reduction at 1.75 GHz by 63% without significantly affecting the performance of the PIFA antenna. © 2007 Wiley Periodicals, Inc. Microwave Opt Technol Lett 49: 949–953, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.22316
Refractive index sensor based on fiber laser
Authors: Yang Xiufeng , Luo Shaojun , Chen Zhihao , Ng Jun Hong
Published: February 2007

A refractive index sensor based on the transient behavior of the fiber laser is presented. The refractive index was measured by monitoring the delay time of the lasing from the pump excitation time. High refractive index sensitivity of 10−6 can be obtained. © 2007 Wiley Periodicals, Inc. Microwave Opt Technol Lett 49: 916–918, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.22318
Surface‐wave bandgap of polarization dependent electromagnetic bandgap structures
Authors: Fu Yunqi , Yuan Naichang
Published: February 2007

Polarization‐dependent reflection‐phase feature could be realized by using a rectangular patch in mushroom‐like electromagnetic bandgap (EBG) structures. The surface‐wave bandgap of this polarization‐dependent EBG structure have been investigated in this article. It has been shown that the surface‐wave bandgap along two periodic directions almost overlaps and compactness in one direction could be achieved by increase the length of the other. One compact EBG microstrip line has been presented. © 2007 Wiley Periodicals, Inc. Microwave Opt Technol Lett 49: 949–949, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.22321
Novel bandpass filter with size reduction and harmonic suppression
Authors: Zhang Xiu‐Yin , Xue Quan , Hu Bin‐Jie
Published: February 2007

A novel microstrip bandpass filter with size reduction and harmonic suppression is proposed in this article. The filter is based on microstrip open loop resonators with coupled open stubs. By adding coupled open stubs to open loop resonator, extra controllable transmission zero can be obtained. The extra transmission zero can be tuned at the second harmonic frequency to suppress spurious response. When compared with the conventional microstrip open‐loop bandpass filter, this filter could achieve size reduction and spurious responses suppression simultaneously. A demonstration filter was designed, fabricated, and measured. Theoretical and experimental results are presented and show good agreement. © 2007 Wiley Periodicals, Inc. Microwave Opt Technol Lett 49: 914–916, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.22323
Language and communication development in down syndrome
Authors: Roberts Joanne E. , Price Johanna , Malkin Cheryl
Published: February 2007

Although there is considerable variability, most individuals with Down syndrome have mental retardation and speech and language deficits, particularly in language production and syntax and poor speech intelligibility. This article describes research findings in the language and communication development of individuals with Down syndrome, first briefly describing the physical and cognitive phenotype of Down syndrome, and two communication related domains—hearing and oral motor skills. Next, we describe language development in Down syndrome, focusing on communication behaviors in the prelinguistic period, then the development of language in children and adolescents, and finally language development in adults and the aging period. We describe language development in individuals with Down syndrome across four domains: phonology, semantics, syntax, and pragmatics. Wethen suggest strategies for intervention and directions for research relating to individuals with Down syndrome. © 2007 Wiley‐Liss, Inc. MRDD Research Reviews 2007;13:26–35.
Language and communicative development in Williams syndrome
Authors: Mervis Carolyn B. , Becerra Angela M.
Published: February 2007

Williams syndrome, a genetic disorder caused by a microdeletion of ∼25 genes on chromosome 7q11.23, is associated with mild to moderate intellectual disability or learning difficulties. Most individuals with Williams syndrome evidence a cognitive profile including relative strengths in verbal short‐term memory and language, and considerable weakness in visuospatial construction. The syndrome has often been argued to provide strong evidence for the independence of language from other aspects of cognition. We provide a brief history of early research on the language abilities of individuals with Williams syndrome and then review contemporary studies of language and cognition in Williams syndrome, beginning with a consideration of performance on standardized assessments. In the remainder of the article, we first consider early language acquisition, with a focus on speech production and perception, vocabulary acquisition, and communicative/pragmatic development and then consider the language abilities of school‐age children and adolescents, focusing on semantics, grammar, and pragmatics. We argue that rather than being the paradigm case for the independence of language from cognition, Williams syndrome provides strong evidence of the interdependence of many aspects of language and cognition. © 2007 Wiley‐Liss, Inc. MRDD Research Reviews 2007;13:3–15.
The study of autism as a distributed disorder
Authors: Müller Ralph‐Axel
Published: February 2007

Past autism research has often been dedicated to tracing the causes of the disorder to a localized neurological abnormality, a single functional network, or a single cognitive‐behavioral domain. In this review, I argue that autism is a “distributed disorder” on various levels of study (genetic, neuroanatomical, neurofunctional, behavioral). “Localizing” models are therefore not promising. The large array of potential genetic risk factors suggests that multiple (or all) emerging functional brain networks are affected during early development. This is supported by widespread growth abnormalities throughout the brain. Interactions during development between affected functional networks and atypical experiential effects (associated with atypical behavior) in children with autism further complicate the neurological bases of the disorder, resulting in an “exponentially distributed” profile. Promising approaches to a better characterization of neural endophenotypes in autism are provided by techniques investigating white matter and connectivity, such as MR spectroscopy, diffusion‐tensor imaging (DTI), and functional connectivity MRI. According to a recent hypothesis, the autistic brain is generally characterized by “underconnectivity.” However, not all findings are consistent with this view. The concepts and methodology of functional connectivity need to be refined and results need to be corroborated by anatomical studies (such as DTI tractography) before definitive conclusions can be drawn. © 2007 Wiley‐Liss, Inc. MRDD Research Reviews 2007;13:85–95.