bluuebunny/crossref_metadata_2025 huggingface dataset:
Nonsteroidal anti‐inflammatory drugs and other analgesic use and bladder cancer in northern New England
Authors: Baris Dalsu , Karagas Margaret R. , Koutros Stella , Colt Joanne S. , Johnson Alison , Schwenn Molly , Fischer Alexander H. , Figueroa Jonine D. , Berndt Sonja I. , Han Summer , Beane Freeman Laura E. , Lubin Jay H. , Cherala Sai , Cantor Kenneth P. , Jacobs Kevin , Chanock Stephen , Chatterjee Nilanjan , Rothman Nathaniel , Silverman Debra T.
Published: April 2012

A few epidemiologic studies have found that use of nonsteroidal anti‐inflammatory drugs (NSAIDs) is associated with reduced risk of bladder cancer. However, the effects of specific NSAID use and individual variability in risk have not been well studied. We examined the association between NSAIDs use and bladder cancer risk, and its modification by 39 candidate genes related to NSAID metabolism. A population‐based case–control study was conducted in northern New England, enrolling 1,171 newly diagnosed cases and 1,418 controls. Regular use of nonaspirin, nonselective NSAIDs was associated with reduced bladder cancer risk, with a statistically significant inverse trend in risk with duration of use (ORs of 1.0, 0.8, 0.6 and 0.6 for <5, 5–9, 10–19 and 20+ years, respectively; ptrend = 0.015). This association was driven mainly by ibuprofen; significant inverse trends in risk with increasing duration and dose of ibuprofen were observed (ptrend = 0.009 and 0.054, respectively). The reduced risk from ibuprofen use was limited to individuals carrying the T allele of a single nucleotide polymorphism (rs4646450) compared to those who did not use ibuprofen and did not carry the T allele in the CYP3A locus, providing new evidence that this association might be modified by polymorphisms in genes that metabolize ibuprofen. Significant positive trends in risk with increasing duration and cumulative dose of selective cyclooxygenase (COX‐2) inhibitors were observed. Our results are consistent with those from previous studies linking use of NSAIDs, particularly ibuprofen, with reduced risk. We observed a previously unrecognized risk associated with use of COX‐2 inhibitors, which merits further evaluation.
Hypoxia and HIF‐1 increase S100A8 and S100A9 expression in prostate cancer
Authors: Grebhardt Sina , Veltkamp Christian , Ströbel Philipp , Mayer Doris
Published: April 2012

S100A8 and S100A9, two heterodimer‐forming members of the cytosolic S100 Ca2+ signaling protein family, are overexpressed in various cancer types, including prostate cancer. They act as proinflammatory danger signals when secreted to the extracellular space and are thought to play an important role during tumorigenesis, affecting inflammatory processes, proliferation, invasion and metastasis of tumor cells. Despite this fact, little is known about tumor environmental factors influencing S100A8/A9 expression. The aim of this study was to test the effect of hypoxia and its master transcriptional regulator hypoxia‐inducible factor 1 (HIF‐1) on S100A8/A9 expression. Hypoxia treatment resulted in induction of S100A8/A9 protein and mRNA expression in prostate epithelial BPH‐1 cells, the latter was also confirmed in the prostate cancer cell lines PC‐3 and DU‐145. Furthermore, overexpression of HIF‐1α caused increase in S100A8/A9 protein and mRNA expression as well as secretion. Functional hypoxia response elements mediating promoter activation on HIF‐1α overexpression were identified within the S100A8 and S100A9 promoters using promoter luciferase reporter constructs. Binding of HIF‐1α to S100A8 and S100A9 promoters was confirmed by chromatin immunoprecipitation. Immunohistochemical analysis of a prostate cancer tissue array showed clear correlation of S100A8 and S100A9 with HIF‐1α expression. Multivariate proportional hazard analysis revealed association of high S100A9 level with time to prostate cancer recurrence. In conclusion, we identified hypoxia and HIF‐1 as novel regulators of S100A8/A9 expression in prostate cancer. S100A9 might be useful as prognostic marker for prostate cancer recurrence after radical prostatectomy.
In vitro delivery, cytotoxicity, swelling, and degradation behavior of a liquid‐to‐solid gelling polymer system for cerebral aneurysm embolization
Authors: Brennecka Celeste R. , Preul Mark C. , Vernon Brent L.
Published: April 2012

This study examines the in vitro characteristics of a crosslinking polymer system for cerebral aneurysm embolization. The polymeric material is composed of poly(propylene glycol)diacrylate (PPODA) and pentaerythritol tetrakis(3‐mercaptopropionate) (QT), formulated with the liquid contrast agents Conray™ or Omnipaque™ 300. The PPODA–QT system was tested for delivery feasibility through mock delivery into a model aneurysm. Cytotoxicity was performed by exposing 3T3 cells to gel formulations, followed by a cell viability assay. Swelling was measured on samples submerged in 150 mM phosphate buffered saline at 37 or 50°C. The same samples underwent compression testing to assess degradation, characterized by reduction in Young's modulus over time. The PPODA–QT system was easily deliverable to mock aneurysms. Cytotoxicity results indicated that Conray‐formulated gels are initially less toxic than Omnipaque‐formulated gels, but show greater susceptibility to swelling and degradation over time. In general, these experiments represented more challenging conditions than would be present in vivo, and therefore, reported results are likely overestimations of in vivo outcomes. However, these results highlight potential issues with each PPODA–QT formulation. Given the desired outcome of neointimal tissue growth over the polymer material, initial cytotoxicity may be more important than long‐term factors when choosing an optimal formulation for aneurysm embolization. © 2012 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 2012.
Expanding molecular modeling and design tools to non‐natural sidechains
Authors: Gfeller David , Michielin Olivier , Zoete Vincent
Published: April 2012

Protein–protein interactions encode the wiring diagram of cellular signaling pathways and their deregulations underlie a variety of diseases, such as cancer. Inhibiting protein–protein interactions with peptide derivatives is a promising way to develop new biological and therapeutic tools. Here, we develop a general framework to computationally handle hundreds of non‐natural amino acid sidechains and predict the effect of inserting them into peptides or proteins. We first generate all structural files (pdb and mol2), as well as parameters and topologies for standard molecular mechanics software (CHARMM and Gromacs). Accurate predictions of rotamer probabilities are provided using a novel combined knowledge and physics based strategy. Non‐natural sidechains are useful to increase peptide ligand binding affinity. Our results obtained on non‐natural mutants of a BCL9 peptide targeting beta‐catenin show very good correlation between predicted and experimental binding free‐energies, indicating that such predictions can be used to design new inhibitors. Data generated in this work, as well as PyMOL and UCSF Chimera plug‐ins for user‐friendly visualization of non‐natural sidechains, are all available at http://www.swisssidechain.ch. Our results enable researchers to rapidly and efficiently work with hundreds of non‐natural sidechains. © 2012 Wiley Periodicals, Inc.
An unusual case of giant cardiac fibroelastoma mimicking left atrial myxoma in a patient presenting with syncope
Authors: Khoueiry Georges , Geha Fady , Meghani Mustafain , Abi Rafeh Nidal , Azab Basem , Torbey Estelle , Asgarian Kourosh T. , Sicat Michael
Published: April 2012

Cardiac papillary fibroelastomas are the most common primary valvular tumors. Generally benign, they account only for about 10% of all primary cardiac neoplasms, can occur in normal or diseased hearts, and are associated strongly with open heart surgery and radiotherapy. They are, in most cases, incidental findings, but can be discovered after syncope. We report the case of an elderly female, who was referred for syncope and was found to have a large fibroelastoma at the mitral valve annulus, intermittently obstructing the left ventricular inflow tract, and mimicking the presentation of left atrial myxoma. This case illustrates another potential mechanism of syncope in patients with fibroelastomas. © 2012 Wiley Periodicals, Inc. J Clin Ultrasound, 2013
In utero treatment of fetal goitrous hypothyroidism in a euthyroid mother: A case report
Authors: Stewart Chantal J.M. , Constantatos Sonia , Joolay Yaseen , Muller Linnie
Published: April 2012

Fetal goitrous hypothyroidism is a rare condition in euthyroid pregnant women. Complications such as tracheal and esophageal compression with resultant polyhydramnios, as well as the possibility of neurodevelopmental effects of hypothyroidism, have prompted prenatal treatment with intra‐amniotic L‐thyroxine. We report a case of this condition and its in utero management. © 2012 Wiley Periodicals, Inc. J Clin Ultrasound, 2012
Does lenticulostriate vasculopathy predipose to ischemic brain infarct? A case report
Authors: Ivanov Ivan , Zlatareva Dora , Pacheva Iliyana , Panova Margarita
Published: April 2012

Lenticulostriate vasculopathy (LSV) is a sonographic finding in infancy with obscure etiology and variable diagnostic and prognostic significance. Ischemic infarct in the territory of the lenticulostriate vessels after mild head trauma is a rare pathology. There are no publications on LSV followed by ischemic infarct. We present the case of an 8‐month‐old boy who suffered mild head trauma and developed an ischemic brain infarct in the territory of preexisting LSV. It is speculated that LSV might be a predisposing factor for ischemic brain infarct after mild head trauma in infants. © 2012 Wiley Periodicals, Inc. J Clin Ultrasound, 2012
Effect of low‐level laser therapy on intramembranous and endochondral autogenous bone grafts healing
Authors: Biguetti Claudia Cristina , Filho Emílio José Marquardt , de Andrade Holgado Leandro , Caviquioli Gustavo , Moreschi Eduardo , Comparin Eliston , Matsumoto Mariza Akemi
Published: April 2012

The aim of this study was to evaluate the healing process of intramembranous (IM) and endochondral (EC) bone grafts under low‐level laser therapy (LLLT). Male rabbits underwent onlay autogenous bone grafts (1 cm in diameter) retrieved from the calvaria and iliac crest and fixed on parietal bones, divided into four groups: Calvaria (C), Iliac (I), Calvaria + LLLT (C+L), and Iliac + LLLT (I+L). Animals from C+L and I+L Groups had their grafts exposed to LLLT (AlGaAs–808 nm, CW, 30 mW, 0.028 cm2 average laser beam area), 15 s irradiation time (16 J/cm2 per point–total of 64 J/cm2 per session). After 7, 14, 30, and 60 days, grafts were retrieved and resorption pattern analyzed by means of morphometry and TRAP‐positive osteoclasts detection. Differences in the resorption levels of iliac grafts were observed, presenting 40% in I group against 8% in I+L grafts at the 14th day of evaluation (P < 0.05). After 30 days, resorption was maintained at 41% in I group, whereas I+L presented 15% in the same period (P = 0.0591). No significant differences were noted in the rates of calvaria grafts resorption in all periods. A significant higher number of osteoclasts on the grafts' surface was observed in C+L Group at day 30, in comparison with C group. In I+L Group, prevalence of osteoclasts was marked at day 7 (P < 0.05) in comparison to I Group. In general, it was concluded that biomodulative effects of LLLT did not significantly affect healing and resorption processes of autogenous bone grafts from EC and IM origins. Microsc. Res. Tech. 75:1237–1244, 2012. © 2012 Wiley Periodicals, Inc.
Body mass, phylogeny and diet composition affects kidney morphology in passerine birds
Authors: Barceló Gonzalo , Salinas Jonathan , Sabat Pablo
Published: April 2012

We studied the renal morphology of 16 species of passerines to assess whether the composition of the diet of birds have been paralleled by differences in the characteristics of the kidneys. We determined the number and length of the medullary cones and the percentage of renal medulla in birds with contrasting dietary habits and then correlated these features with the percentage of nitrogen and proportion of invertebrates in the diet. To examine the correlation between kidney and diet variables, we first used standard correlation and least square regression, and correlation and regression on phylogenetically independent data. We found that the mass of the medullary portion of the kidney, and the medullary cone length were negatively correlated with the percentage of invertebrates present in the diet. We hypothesized that the further development of the renal medulla observed in granivorous birds may be correlated with the small amount of water present in the seeds. Our results suggest that the availability of water in different foods is probably one of the main factors that have led to structural and probably functional changes of the kidney in the studied species. J. Morphol., 2012. © 2012 Wiley Periodicals, Inc.
MicroRNA expression in mouse oligodendrocytes and regulation of proteolipid protein gene expression
Authors: Wang Erming , Cambi Franca
Published: April 2012

Overexpression of the major myelin proteolipid protein (PLP) is detrimental to brain development and function and is the most common cause of Pelizaeus‐Merzbacher disease. microRNA (miRNA), small, noncoding RNAs, have been shown to play critical roles in oligodendrocyte lineage. In this study, we sought to investigate whether miRNAs control PLP abundance. To identify candidate miRNAs involved in this regulation, we have examined differentiation‐induced changes in the expression of miRNAs in the oligodendroglial cell line Oli‐neu and in enhanced green fluorescent protein positive oligodendrocytes ex vivo. We have identified 145 miRNAs that are expressed in oligodendrocyte cell lineage progression. Dicer1 expression decreases in differentiated oligodendrocytes, and knock down of Dicer1 results in changes in miRNAs similar to those associated with differentiation. To identify miRNAs that control the PLP expression, we have selected miRNAs whose expression is lower in differentiated vs. undifferentiated Oli‐neu cells and that have one or more binding site(s) in the PLP 3′‐untranslated region (3′UTR). The PLP 3′UTR fused to the luciferase gene reduces the activity of the reporter, suggesting that it negatively regulates message stability or translation. Such suppression is relieved by knock down of miR‐20a. Overexpression of miR‐20a decreases expression of the endogenous PLP in primary oligodendrocytes and of the reporter gene. Deletion or mutation of the putative binding site for miR‐20a in the PLP 3′UTR abrogated such effects. Our data indicate that miRNA expression is regulated by Dicer1 levels in differentiated oligodendrocytes and that miR‐20a, a component of the cluster that controls oligodendrocyte cell number, regulates PLP gene expression through its 3′UTR. © 2012 Wiley Periodicals, Inc.
Increase of ryanodine receptors by dopamine D1 receptors is negatively regulated by γ‐aminobutyric acid type B receptors in primary cultures of mouse cerebral cortical neurons
Authors: Kurokawa Kazuhiro , Mizuno Koji , Ohkuma Seitaro
Published: April 2012

Although upregulation of ryanodine receptor (RyR)‐1 and ‐2 is mediated through the activation of dopamine D1 receptors (D1DRs) in the development of psychostimulant‐induced place preference, little is known about how such increased expressions of RyRs are negatively regulated. This study investigated negative regulatory mechanisms of increase of RyR‐1 and ‐2 expression by D1DR stimulation with its full agonist, SKF82958 or A 68930, using cultures of mouse cerebral cortical neurons. Sustained exposure to SKF82958 or A 68930 of the neurons increased RyR‐1 and ‐2 proteins in a dose‐ and time‐dependentmanner. The SKF82958‐induced increases of RyR‐1 and ‐2 proteins were significantly suppressed by SCH23390 (a selective D1DR antagonist). In addition, the SKF82958‐ or A 68930‐induced increases of RyR‐1 and ‐2 proteins were completely abolished by baclofen (a selective γ‐aminobutyric acid type B [GABAB] receptor agonist), whereas muscimol (an agonist specific to GABAA receptors) had no effect. SKF82958 or A 68930 significantly increased intracellular cAMP level, which was completely suppressed by baclofen. Furthermore, sustained exposure to phorbol 12,13‐dibutyrate, a protein kinase C activator, did not change the expression of RyR‐1 or ‐2 proteins. Immunohistochemical study showed colocalizaton of immunoreactivities for three types of proteins, D1DRs and GABAB receptor R1 and R2 subunits in the same neuronal bodies, suggesting that the neurochemical changes induced by the activation of D1DRs and GABAB receptors occur in the same neurons. These results indicate that RyR‐1 and ‐2 expression facilitated by D1DR stimulation are negatively regulated by GABAB receptor via suppression of cAMP production. © 2012 Wiley Periodicals, Inc.
Expression pattern of ataxia telangiectasia mutated (ATM), p53, Akt, and glycogen synthase kinase‐3β in the striatum of rats treated with 3‐nitropropionic acid
Authors: Duran‐Vilaregut Joaquim , Manich Gemma , del Valle Jaume , Camins Antoni , Pallàs Mercè , Vilaplana Jordi , Pelegrí Carme
Published: April 2012

3‐Nitropropionic acid (3‐NPA) is a mitochondrial toxin used in the laboratory to replicate neurodegenerative conditions that are accompanied by degeneration of the caudate‐putamen. 3‐NPA induces depletion in ATP production, reactive oxygen species production, and secondary excitotoxicity mediated by activation of N‐methyl‐D‐aspartate receptors that culminates in the triggering of cell death mechanisms, including apoptosis. We here examined by immunohistochemical methods whether cellular expression of phosphoSer1981‐ataxia telangiectasia mutated (ATM), phosphoSer15‐p53, phosphoSer473‐Akt, and phosphoSer9‐glycogen synthase kinase‐3β (GSK3β), which are key signal molecules that play a critical role in regulating cellular processes related to cell survival and demise, were involved in the striatal neurodegeneration in the brains of rats treated with 3‐NPA. Our results indicate that the toxin induced the activation of ATM and p53 only in astrocytes, and a role for these proteins in neuronal degeneration was ruled out. On the other hand, striatal neurons lost the active form of Akt as soon as they began to appear pyknotic, indicating impairment of the PI3K/Akt/GSK3 pathway in their degenerative process. The inactive form of GSK3β was detected extensively, mainly in the rim of the striatal lesions around degenerating neurons, which could be attributed to a cell death or cell survival response. © 2012 Wiley Periodicals, Inc.
Clostridium difficile infection in hospitalized liver transplant patients: A nationwide analysis
Authors: Ali Muhammad , Ananthakrishnan Ashwin N. , Ahmad Shahryar , Kumar Nilay , Kumar Gagan , Saeian Kia
Published: April 2012

The incidence of Clostridium difficile infection (CDI) is increasing among hospitalized patients. Liver transplantation (LT) patients are at higher risk for acquiring CDI. Small, single-center studies (but no nationwide analyses) have assessed this association. We used the Nationwide Inpatient Sample of the Healthcare Cost and Utilization Project (2004-2008) for this retrospective, cross-sectional study. Patients with any discharge diagnosis of LT composed the study population, and they were identified with International Classification of Diseases, Ninth Revision, Clinical Modification codes. Those with a discharge diagnosis of CDI were considered cases. Our primary outcomes were the prevalence of CDI and the effects of CDI on inpatient mortality. Our secondary outcomes included the length of stay and hospitalization charges. A regression analysis was used to derive odds ratios (ORs) adjusted for potential confounders. There were 193,174 discharges with a diagnosis of LT from 2004 to 2008. The prevalence of CDI was 2.7% in the LT population and 0.9% in the non-LT population (P < 0.001). Most of the LT patients were 50 to 64 years old. LT patients had higher odds of developing CDI [OR = 2.88, 95% confidence interval (CI) = 2.68-3.10]. Increasing age and increasing comorbidity (including inflammatory bowel disease and nasogastric tube placement) were also independent CDI risk factors. CDI was associated with a higher mortality rate: 5.5% for LT patients with CDI versus 3.2% for LT-only patients (adjusted OR = 1.70, 95% CI = 1.29-2.25). In conclusion, the prevalence of CDI is higher for LT patients versus non-LT patients (2.7% versus 0.9%). CDI is an independent risk factor for mortality in the LT population. Liver Transpl, 2012. © 2012 AASLD.
Thermoresponsive Poly(N‐isopropylacrylamide)‐Based Block Copolymer Coating for Optimizing Cell Sheet Fabrication
Authors: Nakayama Masamichi , Yamada Naoko , Kumashiro Yoshikazu , Kanazawa Hideko , Yamato Masayuki , Okano Teruo
Published: April 2012

Thermoresponsive surfaces are prepared via a spin‐coating method with a block copolymer consisting of poly(N‐isopropylacrylamide) (PIPAAm) and poly(butyl methacrylate) (PBMA) on polystyrene surfaces. The PBMA block suppresses the removal of deposited PIPAAm‐based polymers from the surface. The polymer coating affects the temperature‐dependent cellular behavior of the surfaces with respect to protein adsorption. By adjusting layer thicknesses, PBMA‐b‐PIPAAm‐coated surfaces are optimized to regulate the adhesion/detachment of cells by temperature changes. Thus, thermoresponsive polymer‐coated surfaces are able to harvest contiguous cell sheets with their basal extracellular matrix proteins.

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Stochastic logistic equation with infinite delay
Authors: Liu Meng , Wang Ke
Published: April 2012

This paper perturbs the famous logistic equation with infinite delay
urn:x-wiley:01704214:media:mma1608:mma1608-math-0001 into the corresponding stochastic system
urn:x-wiley:01704214:media:mma1608:mma1608-math-0002

This study shows that the above stochastic system has a global positive solution with probability 1 and gives the asymptotic pathwise estimation of this solution. In addition, the superior limit of the average in time of the sample path of the solution is estimated. This work also establishes the sufficient conditions for extinction, nonpersistence in the mean, and weak persistence of the solution. The critical value between weak persistence and extinction is obtained. Then these results are extended to n‐dimensional stochastic Lotka–Volterra competitive system with infinite delay. Finally, this paper provides some numerical figures to illustrate the results. The results reveal that, firstly, different types of environmental noises have different effects on the persistence and extinction of the population system; secondly, the delay has no effect on the persistence and extinction of the stochastic system.Copyright © 2012 John Wiley & Sons, Ltd.
46‐W high efficiency unbalanced doherty power amplifier in extended output power back‐off
Authors: Jang Dong‐Hee , Kim Ji‐Yeon , Kim Jong‐Heon
Published: April 2012

A 46‐W unbalanced Doherty amplifier is proposed to obtain high efficiency at the output power back‐off beyond 6 dB using the same type of transistors in both the main and the peaking amplifier.An added power efficiency of 38% and an adjacent channel power ratio of −35.6 dBc were measured for a CDMA2000 1FA signal. © 2012 Wiley Periodicals, Inc. Microwave Opt Technol Lett 54:1612–1614, 2012; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.26865
Design and experimental study of a fiber bragg grating chirped tuning method
Authors: Li Lijun , Ma Hui , Cao Hui , Ma Weihong , Yin Xingbin , Zhang Yong , Cao Maoyong
Published: April 2012

In this article, fiber Bragg grating chirped tuning method is theoretically and experimentally demonstrated. Using a double‐arched structure and a metal diaphragm, a vertical pressure can be transmitted to grating. According to different metal diaphragm shapes and grating pasted paths, by changing the pressure, fiber grating spectrum chirped tuning can be achieved. When it is pressurized, the internal strain distributions of metal diaphragm are simulated using finite element method. This uniform fiber Bragg grating chirped tuning method is also experimentally studied. The chirped tuning of fiber Bragg grating can be achieved. By introducing a correction factor, the theoretical and experimental results agree very well. © 2012 Wiley Periodicals, Inc. Microwave Opt Technol Lett 54:1582–1585, 2012; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.26866
Tri‐bandpass filter based on two stepped impedance resonators
Authors: Moussa Rachida , Palukuru Vamsi K. , Sowpati Arun K. , Essaaidi Mohamed , Jantunen Heli , Aghoutane Mohamed
Published: April 2012

A novel approach for dual‐ and tri‐band bandpass filters (BPF) design with independently controlled center frequencies and bandwidths was presented. On the one hand, a stepped impedance resonator (SIR) is designed to operate at the center frequencies of two bands simultaneously (dual‐band), on the other hand, two SIR s are designed to operate at the center frequencies of three bands simultaneously (tri‐band). To verify the proposed approach, a tri‐BPF has been designed and fabricated with printed circuit board technology. The measured results are in good agreement with the simulation results. © 2012 Wiley Periodicals, Inc. Microwave Opt Technol Lett 54:1765–1768, 2012; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.26868
A meandered inverted‐f capsule antenna for an ingestible medical communication system
Authors: Seo Wonbum , Kim Uisheon , Lee Soonyong , Kwon Kyeol , Choi Jaehoon
Published: April 2012

In this article, a capsule antenna used in an ingestible medical device is proposed. To achieve miniaturization and a wide bandwidth, an inverted‐F antenna with a meandered strip line was used. The antenna performance in a human voxel model is analyzed through simulation, and the performance of the fabricated antenna is verified by comparing the measured data with that of the simulation, when the antenna is placed in a human‐equivalent liquid phantom. To investigate the performance of the proposed antenna in an indoor environment, a typical sickroom model is set‐up, and the propagation characteristics between the proposed antenna and the base station are analyzed at 1.4 GHz. © 2012 Wiley Periodicals, Inc. Microwave Opt Technol Lett 54:1761–1765, 2012; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.26869
A compact hepta‐band antenna for portable and embedded devices
Authors: Boldaji Ashkan , Bialkowski Marek E.
Published: April 2012

The article presents the design of a compact hepta‐band antenna for portable and embedded applications targeting the GSM‐900/DCS/PCS/UMTS‐2100 cellular and 2.4/5.2/5.5‐GHz WLAN bands. A printed inverted‐F antenna with a folded primary arm and a second radiating arm on the bottom surface of the substrate initially provides tri‐band operation in the 900, 1700, and 2450‐MHz bands. The shorting‐arm is relocated below the primary arm for a reduction in occupied area. The addition of a long slot in the ground plane offers an additional operation around 2100 MHz, bridging the 1700‐ and 2450‐MHz resonances and promoting significantly wide‐band performance of more than 900 MHz in that band. A second ground slot allows the antenna to support two of the 5‐GHz WLAN bands. Laboratory measurements confirm the performance of the final hepta‐band antenna, with 6‐dB return loss met from 880–1000, 1680–2590, and 5150–5710 MHz, and better than 10‐dB return loss at the centers and edges of these bands. © 2012 Wiley Periodicals, Inc. Microwave Opt Technol Lett 54:1614–1618, 2012; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.26872
A method to adjust enhanced X‐band microwave transmission and beaming using asymmetric gratings
Authors: Liu Yu , Cao Jin‐xiang , Liu Jun‐ming , Du Yin‐chang , Zheng Zhe , Wang Jian
Published: April 2012

We present a method to adjust enhanced X‐band microwave transmission and beaming through controlling the distance between grooves on the front and back surface of asymmetric gratings.Extraordinary transmission and beaming effect was influenced at X‐band microwave frequencies (8–12 GHz). It demonstrates a new way to achieve directional selectivity in microwave frequencies. © 2012 Wiley Periodicals, Inc. Microwave Opt Technol Lett 54:1599–1601, 2012; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.26874
Compact monopole antenna with two strips and a rectangular‐slit ground plane for dual‐band WLAN/WiMAX applications
Authors: Yoon Joong Han , Kil Gyung‐Suk
Published: April 2012

A novel design of a simple microstrip‐fed monopole antenna for wireless local‐area network/worldwide interoperability of microwave access (WLAN/WiMAX) band operation is proposed in this article. The proposed antenna consists of two branch strip, an asymmetrical ground plane, and a rectangular‐slit ground plane. The proposed antenna is capable of generating two separate resonant modes with good impedance‐matching conditions. Prototypes of the proposed antenna were fabricated and experimentally measured. Acceptable agreement between the measurement and simulation results was achieved. The numerical and experiment results demonstrate that the proposed antenna satisfies the return loss −10 dB (VSWR < 1:2) impedance bandwidth requirement while simultaneously covering the WLAN and WiMAX bands. Meanwhile, the two‐dimensional radiation pattern and three‐dimensional gain performance of the antenna in the operation bands were also observed and discussed. © 2012 Wiley Periodicals, Inc. Microwave Opt Technol Lett 54:1559–1566, 2012; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.26875
Adjustable fluidic lenses for correcting piston/defocus/astigmatism aberrations induced by MEMS deformable mirrors
Authors: Fuh Yiin‐Kuen , Hsu Kuo‐Chan , Lin Ming‐Xin , Fan Jia‐Ren
Published: April 2012

An adjustable fluidic lens is typically utilizing curvature change and is promising to correct the aberrations such as piston, defocus, and astigmatism. In this article, capability of adjustable fluidic lenses to correct the induced wavefront aberrations is investigated systematically, with particular attention placed on interpretation of Zernike modes and exploration of the potentials of fluidic lenses. In addition, aberrations are expressed in Zernike polynomials and the first six modes commonly encountered in ophthalmology are carefully examined. Three different wavefront aberrations are intentionally induced by a commercial micro‐electrical‐mechanical systems (MEMS) deformable mirrors (DM) with 140 actuators. The optical properties of fluidic lenses corrections are characterized by Shack–Hartmann measurements. Experimental results show that piston mode (Z1) can be significantly improved from 0.972 to −0.031 μm using fluidic lenses by injecting DI water as little as 0.02 ml (resultant meniscus curvature is 392.8 mm). Similar improvements can be found in defocus (Z5)/astigmatism (Z6) and aberrations are reduced for both modes from −0.15 μm/−0.48 μm to 0.02 μm/0.085 μm, respectively. When injected volume of 0.1 ml (resultant meniscus curvature is 78.9 mm), we can experimentally deduce that aberrations of Z3/Z5 induced by MEMS DM at a magnitude of 0.486 μm/−1.472 μm, fluidic lenses can only marginally improved to −0.245 μm/0.305 μm. © 2012 Wiley Periodicals, Inc. Microwave Opt Technol Lett 54:1701–1705, 2012; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.26878
Optical wireless indoor positioning system using light emitting diode ceiling lights
Authors: Jung Soo‐Yong , Hann Swook , Park Suyong , Park Chang‐Soo
Published: April 2012

We proposed an optical wireless position sensing system using light emitting diodes (LEDs), demonstrating it via experiment.During experiment, we used four LED lamps composed of 16 LED chips with a view angle of 65° at half power. Further, we assigned a unique address for each LED lamp, being transmitted using LED properties such as lighting and switching. Afterward, we used correlation to locate the target. The proposed positioning system displayed 4.38 cm of mean distance error among 36 points with dimensions of 1 × 1 × 1.2 m3. © 2012 Wiley Periodicals, Inc. Microwave Opt Technol Lett 54:1622–1626, 2012; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.26880
A dual‐resonance CMOS voltage‐controlled oscillator with enhanced performance through new varactor topology
Authors: Jang Sheng‐Lyang , Cheng Ching‐Lun , Chang Chia‐Wei , Huang Jhin‐Fang
Published: April 2012

A new fully integrated, dual‐band CMOS voltage controlled oscillator (VCO) is presented. The VCO is composed of a p‐core cross‐coupled and an n‐core cross‐coupled Colpitts oscillator with dual‐resonance LC tank and was implemented in 90‐nm CMOS technology with 1.15 V supply voltage. The circuit allows the VCO to operate at two resonant frequencies with a common LC tank. This VCO is configured with 6.3 and 10 GHz frequency bands with differential outputs. The dual‐band VCO operates at 6.11–6.413 GHz and 9.72–10.24 GHz. The phase noises of the VCO operating at 9.72 and 6.4 GHz are −116.31 dBc/Hz and −122.79 dBc/Hz at 1‐MHz offset, respectively, while the VCO draws 4/4.28 mA and 4.6/4.92 mW consumption at high/low frequency band from a 1.15‐V supply. © 2012 Wiley Periodicals, Inc. Microwave Opt Technol Lett 54:1590–1593, 2012; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.26882
A design for circularly polarized ring slot antennas backed by thin grounded substrate
Authors: Liu Wang‐Lin , Chen Mu‐Yi , Chen Tsair‐Rong
Published: April 2012

This article presents a design for circularly polarized ring slot antennas backed by a metal plate with a small separated distance.The antenna is excited through a shorted L‐shaped coupling strip, and good circular polarization performance can be obtained as long as the vertical arm of the L‐shaped coupling strip is properly stretched. Both simulated and measured results demonstrate that the reflector‐backed slot antenna gives an opposite polarization sense to its counterpart without the reflector. © 2012 Wiley Periodicals, Inc. Microwave Opt Technol Lett 54:1768–1770, 2012; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.26885
Printed, coplanar, magnetic‐dipole multiantenna system for 5‐GHz wlan applications
Authors: Lee Cheng‐Tse , Su Saou‐Wen
Published: April 2012

A printed, three‐magnetic‐dipole antenna system symmetrically placed on a single‐layered FR4 substrate suitable for 5‐GHz WLAN applications is presented. The dipoles are set in a sequential, rotating arrangement on a small substrate with an equal inclination angle to form a symmetrical multiantenna structure. Each antenna occupies an area of 7 mm × 10 mm and is spaced 5.4 mm apart from the adjacent dipole. The magnetic dipole has a U‐shaped radiating arm and is capacitively excited by a driven coupling strip. With a compact size (radius less than 15 mm) of the antenna system, the design yet shows a wide operating band with good port isolation attained. Details of a design prototype are described and discussed in the article. © 2012 Wiley Periodicals, Inc. Microwave Opt Technol Lett 54:1726–1731, 2012; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.26886
A novel scheme for seamless integration of RZ‐DPSK‐DWDM optical links with MIMO‐OFDM system
Authors: Shao Yufeng , Chi Nan
Published: April 2012

We introduce 10 × 10 Gb/s RZ‐DPSK‐DWDM links in the architecture integration of MIMO‐OFDM system. The optical communication performance and wireless communication performance is analyzed in the integrated system. The long distance transmission for RZ‐DPSK WDM is done, and the demodulated RZ‐DPSK signal is transformed to the binary data, which is given to MIMO‐OFDM‐QPSK wireless communication system. Two MIMO‐OFDM‐QPSK wireless system is designed with two transmit antennas and one receive antenna and four transmit antennas and one receive antenna. The BER performance of almost 10−3 is achieved at SNR of 11 dB with four transmit antennas and one receive antenna, which is better when compared to two transmit antennas and one receive antenna. The results prove that seamless integration of RZ‐DPSK‐DWDM optical links with MIMO‐OFDM system is suitable to simultaneously offer higher receiver performance and simplify system configuration for fourth generation wide‐area coverage mobile communication. © 2012 Wiley Periodicals, Inc. Microwave Opt Technol Lett 54:1679–1679, 2012; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.26891
A comparative study of c‐shaped, e‐shaped, and u‐slotted patch antennas
Authors: Bhardwaj Shubhendu , Rahmat‐Samii Yahya
Published: April 2012

A class of popular linearly polarized slotted antennas are compared with respect to their RF mechanism, radiation mechanism, impedance matching, and cross polarization characteristics for wireless communication frequency band 1.9–2.4 GHz.It is found that C‐shaped and double C‐shaped patch antennas, even though miniaturized, suffer from narrow bandwidth and high cross polarization level, due to its orientation of slot. U‐slotted and E‐shaped patch antennas show high bandwidth with minor penalty in size and cross polarization level. In order to understand the effect of slot on the radiation in these antennas, a novel strategy of looking at the near‐field of these antennas has been presented. These near‐field plots are analyzed to explain certain far‐field radiation characteristics in these antennas such as‐ cross‐pol level. © 2012 Wiley Periodicals, Inc. Microwave Opt Technol Lett 54:1746–1757, 2012; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.26894
Low‐profile tetra wire‐patch antenna for automotive applications
Authors: Lizzi L. , Ferrero F. , Ribero J. , Staraj R.
Published: April 2012

A wire‐patch antenna operating over the terrestrial trunked radio emergency and public safety standard is presented. It exploits the use of shorting wires to operate below its fundamental cavity resonance mode. Thanks to low‐cost, low‐profile, solidity, ease of fabrication, and dipole‐like radiation pattern properties, it results to be particularly suitable for automotive applications. © 2012 Wiley Periodicals, Inc. Microwave Opt Technol Lett 54:1711–1714, 2012; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.26895
Integral imaging system featuring a seamlessly extended depth of field
Authors: Xu Kai , Hwang Yong‐Seok , Lee Sang‐Shin
Published: April 2012

An integral imaging display system, incorporating three birefringence lens arrays (BLAs) paired with a half‐wave plate (HWP), is proposed to accomplish a seamlessly extended depth of field.The BLAs were built by injecting three different types of liquid crystal into the space between the lens array substrate and glass substrate, and they act either as a concave lens, convex lens, or a transmissive plain homogeneous medium, depending on the light polarization. The HWP is used to adaptively control the polarization of the light impinging on each of the BLAs, to ensure that one of them acts as a concave/convex lens, whereas the others act as a transmissive plain medium. The three BLAs were appropriately aligned to extend the entire depth of field substantially. Consequently, the feasibility of the proposed display system was verified theoretically and experimentally. © 2012 Wiley Periodicals, Inc. Microwave Opt Technol Lett 54:1705–1711, 2012; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.26896
Temperature insensitive bending sensor based on microbending FBG cladding mode recoupling
Authors: Sun An , Wu Zhishen
Published: April 2012

A simple fiber Bragg grating (FBG) bending sensor based on microbending induced cladding mode recoupling is presented, in which cladding mode is excited and recoupled through microbending structure in single mode fiber.Experimental results show that the excited counter‐propagation weak cladding mode in microbending FBG is very sensitive to curvature which can be used for temperature independent bending measurement. © 2012 Wiley Periodicals, Inc. Microwave Opt Technol Lett 54:1674–1676, 2012; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.26897
A quasisemicircular wide‐slot antenna with 3.5‐/5.5‐GHz dual band‐notched characteristics for ultrawideband applications
Authors: Yang Yi , Yin Ying‐Zeng , Liu Bo‐Wen , Jing Shao‐Hong
Published: April 2012

A novel ultrawideband (UWB) wide‐slot antenna with dual‐notched bands is presented and investigated in this article. The radiator is a quasisemicircular slot excited by a fork‐shaped stub. By introducing an arc‐shaped slot and a pair of arc‐shaped strips on the ground, the 3.5‐ and 5.5‐GHz dual band‐rejected filtering properties for worldwide interoperability for microwave access and wireless local area network signals can be achieved well. Measured results demonstrate that the proposed antenna can operate well over UWB frequency band ranging from 2.85 to over 12 GHz, while providing dual‐notched bands (VSWR > 2) covering 3.23–3.71 GHz and 5.03–6.34 GHz. In addition, nearly omnidirectional radiation patterns, stable gain, and moderate group delay variation can also be observed in the operating bands. © 2012 Wiley Periodicals, Inc. Microwave Opt Technol Lett 54:1602–1605, 2012; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.26901
Stabilization of a fiber fabry‐perot interferometric acoustic wave sensor
Authors: Chen Jianyong , Li Wancai , Jiang Hong , Li Zhenyu
Published: April 2012

Control of the operating point of an interferometric optical sensor to produce the highest sensitivity is crucial in the demodulation of interferometric optical sensors to compensate for quadrature point (Q point) mismatching.A new method for operating point control of fiber Fabry‐Perot interferometer was discussed and demonstrated, the relationship of the Fabry‐Perot cavity length, the visibility and the interferometric fringe was analyzed. MCU was introduced to tracing the Q point by changing the laser wavelength through adjusting the light source temperature. It is proved that the dynamic range of the sensor system is surely extended; the NSR could be greatly improved because the wavelength change‐induced noises is greatly limited in this sensor system. © 2012 Wiley Periodicals, Inc. Microwave Opt Technol Lett 54:1668–1671, 2012; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.26902
Tuning of on‐metal UHF RFID inlay tags loaded with a thin magneto‐dielectric slab
Authors: Serra Andrea A. , Guraliuc Anda R. , Nepa Paolo , Manara Giuliano
Published: April 2012

The input impedance of UHF radio frequency identification (RFID) inlay tags is analyzed when a thin material slab is placed between the antenna and a metal surface.The two‐layer slab is made of a thin magneto‐dielectric Emerson&Cuming Eccosorb MCS‐U layer with high permeability/permittivity and a thin Rohacell™ layer. Two common commercial UHF tag antennas are considered: the Alien ALN‐9640 Squiggle® and the ALN‐9654 G inlays. The antenna impedance is evaluated both numerically and experimentally, and the power transmission coefficient is calculated in the whole UHF RFID frequency band. It is shown that a tag nonintrinsically suitable for on‐metal applications (e.g. inlay tags) can be used on a conductive surface in a low‐profile configuration. Indeed, when the above magnetic substrate is used, the antenna input impedance rises up from the very low values induced by the presence of a near conducting surface. Then, with a simple trimming applied to the antenna layout, it is possible to tune the antenna to achieve a conjugate impedance matching with the chip impedance. It is demonstrated how an effective tuning is possible through some simple straight cuts of some antenna parts, without requiring a redesign of a new optimized tag antenna. © 2012 Wiley Periodicals, Inc. Microwave Opt Technol Lett 54:1630–1633, 2012; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.26903
A current‐reused voltage‐controlled oscillator with balanced enlarged amplitude via decoupling capacitance adoption
Authors: Kuo Ko‐Chi , Lin Shun‐Dao , Hou Hsiao‐Han
Published: April 2012

This article presents a low‐power current‐reused voltage‐controlled oscillator (VCO) with a decoupling capacitance. The proposed VCO applies a decoupling capacitance between the power supply and degeneration resistance in the VCO to reduce the unbalanced characteristics of the current‐reused VCO. Adopting the decoupling capacitance can balance and enlarge the output amplitude while enhancing the phase noise. The simulated amplitude unbalance ratio is 5%, compared with 11% of the amplitude unbalance ratio of a conventional current‐reused VCO. In addition, the proposed design enlarges the amplitude by 25%, compared with the amplitude of a conventional current‐reused VCO without increasing power consumption. The proposed design has been fabricated in a TSMC 0.18‐μm CMOS process. The power consumption is 1.6 mW from a 1.8 V supply. The fabricated VCO operates from 2.1 to 2.7 GHz with a 22.7% tuning range. The measured phase noise is −121 dBc/Hz at 1 MHz offset at 2.2 GHz. © 2012 Wiley Periodicals, Inc. Microwave Opt Technol Lett 54:1626–1629, 2012; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.26904
Design of compact dual‐meander antenna for WLAN operation
Authors: Seo Yongseok , Jung Jinwoo , Lee Hyeonjin , Lim Yeongseog
Published: April 2012

A novel and simple design of a coplanar waveguide‐fed dual‐band antenna based on a compact dual‐meander antenna is investigated for wireless local area network (WLAN) applications. The impedance bandwidths achieved can reach about 0.57 GHz (2.13–2.70 GHz) 23.7% at the center frequency of 2.40 and 0.55 GHz (5.20–5.75 GHz) 10.4% at the center frequency of 5.30 GHz. These characteristics meet the required bandwidth specifications of IEEE 802.11a/b/g. The peak antenna gains for the operating frequencies across dual WLAN bands are measured to be 6.30 and 5.16 dBi, respectively. © 2012 Wiley Periodicals, Inc. Microwave Opt Technol Lett 54:1595–1599, 2012; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.26905
A compact design of tunable band‐notched ultrawideband antenna
Authors: Elfergani I. T. E. , Abd‐Alhameed R. A , See C. H. , Jones S. M. R. , Excell P. S.
Published: April 2012

In this letter, a compact ultrawideband planar inverted F‐L antenna with a tunable band‐notched response is presented. Tuning of the rejected frequency bands is realized by loading a variable capacitor on an embedded slot of the proposed antenna structure. The antenna exhibits a wide impedance bandwidth from 3.1 to 10.6 GHz with a good impedance matching (voltage standing wave ratio ≤ 2) and tunable broad range of band‐reject frequency (centre frequency from 3.2 to 6 GHz). To validate the theoretical model and design concept, the antenna prototype was fabricated and measured. © 2012 Wiley Periodicals, Inc. Microwave Opt Technol Lett 54:1642–1644, 2012; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.26907