bluuebunny/crossref_metadata_2025 huggingface dataset:
AMPA GluR‐A receptor subunit mediates hippocampal responsiveness in mice exposed to stress
Authors: Fumagalli Fabio , Caffino Lucia , Vogt Miriam A. , Frasca Angelisa , Racagni Giorgio , Sprengel Rolf , Gass Peter , Riva Marco Andrea
Published: June 2010

Because stress represents a major precipitating event for psychiatric disorders, it is important to identify molecular mechanisms that may be altered in vulnerable individuals when exposed to stress. Here, we studied GluR‐A−/−mice, animals with compromised AMPA receptor signaling, and characterized by a schizophrenic as well as depressive phenotype to investigate changes occurring in response to an acute stress. Wild‐type and GluR‐A−/−mice were exposed to a single immobilization stress and sacrificed immediately after the end of the stress for the analysis of activity regulated genes and of glutamatergic synapse responsiveness. The acute stress produced a marked increase in the hippocampal expression of Arc (activity‐regulated cytoskeletal‐associated protein) in GluR‐A−/−, but not in wild‐type mice, which was associated with a similar increase of phospho‐CaMKII, a partner in the action of Arc. When looking at the glutamatergic response to stress in wild‐type animals, we found that stress increased GluR‐A phosphorylation on serine831, an effect that was paralleled by a significant increase of the phosphorylation of the main NMDA receptor subunits, that is, NR‐1 and NR‐2B. Conversely, the stress‐induced modulation of NMDA receptor subunits was not observed in GluR‐A−/−mice. We suggest that enhanced stress responsiveness in GluR‐A−/−mice may be due, at least in part, to their inability to activate NMDA‐mediated glutamatergic neurotransmission, suggesting that the integrity of AMPA/NMDA receptor function may be important for successful coping under stressful conditions. © 2010 Wiley‐Liss, Inc.
Polydisulfide‐based Biodegradable Macromolecular Magnetic Resonance Imaging Contrast Agents
Authors: Lu Zheng‐Rong , Wu Xueming
Published: June 2010

Macromolecular Gd(III) complexes are advantageous over small molecular Gd(III) complexes in contrast‐enhanced magnetic resonance imaging (MRI) because of their prolonged blood circulation and preferential tumor accumulation. However, macromolecular contrast agents have not been approved for clinical applications because of the safety concerns related to their slow body excretion. Polydisulfide Gd(III) complexes have been designed and developed as biodegradable macromolecular MRI contrast agents to alleviate these concerns by facilitating the clearance of Gd(III) complexes from the body. These agents initially behave as macromolecular agents and result in superior contrast enhancement in the vasculature and tumor tissues. They can then be readily degraded in vivo into small molecular chelates that can be rapidly excretede from the body via renal filtration after the MRI examinations. Various polydisulfide Gd(III) complexes have been prepared as biodegradable macromolecular MRI contrast agents. These agents have resulted in strong contrast enhancement in the vasculature and tumor tissue in animal models with minimal long‐term tissue accumulation when compared to small molecular contrast agents. Polydisulfide Gd(III) complexes are promising for further clinical development as safe and effective biodegradable macromolecular MRI contrast agents for cardiovascular and cancer imaging. The review summarizes the chemistry and properties of polydisulfide Gd(III) complexes.
Novel polyurethanes with interconnected porous structure induce in vivo tissue remodeling and accompanied vascularization
Authors: Jovanovic D. , Engels G. E. , Plantinga J. A. , Bruinsma M. , van Oeveren W. , Schouten A. J. , van Luyn M. J. A. , Harmsen M. C.
Published: June 2010

Tissue engineering and regenerative medicine have furnished a vast range of modalities to treat either damaged tissue or loss of soft tissue or its function. In most approaches, a temporary porous scaffold is required to support tissue regeneration. The scaffold should be designed such that the turnover synchronizes with tissue remodeling and regeneration at the implant site. Segmented polyester urethanes (PUs) used in this study were based on ε‐caprolactone (CL) and co‐monomers D,L‐lactide (D,L‐L) and γ‐butyrolactone (BL), and 1,4‐butanediisocyanate (BDI). In vitro, the PUs were nontoxic and haemocompatible. To test in vivo biocompatibility, the PUs were further processed into porous structures and subcutaneously implanted in rats for a period up to 21 days. Tissue remodeling and scaffold turnover was associated with a mild tissue response. The tissue response was characterized by extensive vascularization through the interconnected pores, with low numbers of macrophages on the edges and stroma formation inside the pores of the implants. The tissue ingrowth appeared to be related to the extent of microphase separation of the PUs and foam morphology. By day 21, all of the PU implants were highly vascularized, confirming the pores were interconnected. Degradation of P(CL/D,L‐L)‐PU was observed at this time, whereas the other two PU types remained intact. The robust method reported here of manufacturing and processing, good mechanical properties, and in vivo tissue response of the porous P(CL/D,L‐L)‐PU and PBCL‐PU makes them excellent candidates as biomaterials with an application for soft tissue remodeling, for example, for cardiovascular regeneration. © 2010 Wiley Periodicals, Inc. J Biomed Mater Res Part A, 2010.
Improved biocompatibility of hydroxyapatite thin film prepared by aerosol deposition
Authors: Park Dong‐Soo , Kim In‐Sook , Kim Hyeongil , Chou Alex Hung Kuo , Hahn Byung‐Dong , Li Long‐Hao , Hwang Soon‐Jung
Published: June 2010

Technical development for an efficient coating of bioactive materials improves the characteristics of a fully functional implant. The aim of this study was to investigate the osteoinductive effect of a newly developed hydroxyapatite (HA)‐coating technique using aerosol deposition without post‐heat treatment [room temperature (RT) group] on the titanium (Ti) dental implant in vitro and in vivo, compared with that of HA coating with post‐heat treatment (HT‐400 group) or machined surface (control group). Cell proliferation or attachment on the HA‐coated Ti surface was assessed using tetrazolium salt, WST‐8 or scanning electron microscopy (SEM). Human osteoblasts (HOB) on RT group were well attached and grew alike in the control or HT‐400 group. The alkaline phosphatase activity of HOB cultured on RT and HT‐400 group was significantly higher than the control group (p < 0.05). Evaluation by SEM, TEM, and XRD demonstrated that aerosol deposition facilitated HA particles to form a dense and uniform HA layer in the RT group despite no post‐heating. In a rabbit tibia model (n = 3), the ratios of bone implant contact and bone area in the RT group (49.88%, 86.05%) were greater than in the HT‐400 group (38.82%, 77.34%) or the control (28.31%, 73.86%). The finding of this study showed that the HA coating using aerosol deposition without post‐heat treatment has a good biocompatibility, and provide a promoting strategy to enhance osseointegration in the application of the dental implant. © 2010 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2010.
Differentiation of cardiomyocytes from human embryonic stem cells is accompanied by changes in the extracellular matrix production of versican and hyaluronan
Authors: Chan Christina K. , Rolle Marsha W. , Potter‐Perigo Susan , Braun Kathleen R. , Van Biber Benjamin P. , Laflamme Michael A. , Murry Charles E. , Wight Thomas N.
Published: June 2010

Proteoglycans and hyaluronan play critical roles in heart development. In this study, human embryonic stem cells (hESC) were used as a model to quantify the synthesis of proteoglycans and hyaluronan in hESC in the early stages of differentiation, and after directed differentiation into cardiomyocytes. We demonstrated that both hESC and cardiomyocyte cultures synthesize an extracellular matrix (ECM) enriched in proteoglycans and hyaluronan. During cardiomyocyte differentiation, total proteoglycan and hyaluronan decreased and the proportion of proteoglycans bearing heparan sulfate chains was reduced. Versican, a chondroitin sulfate proteoglycan, accumulated in hESC and cardiomyocyte cultures. Furthermore, versican synthesized by hESC contained more N‐ and O‐linked oligosaccharide than versican from cardiomyocytes. Transcripts for the versican variants, V0, V1, V2, and V3, increased in cardiomyocytes compared to hESC, with V1 most abundant. Hyaluronan in hESC had lower molecular weight than hyaluronan from cardiomyocyte cultures. These changes were accompanied by an increase in HAS‐1 and HAS‐2 mRNA in cardiomyocyte cultures, with HAS‐2 most abundant. Interestingly, HAS‐3 was absent from the cardiomyocyte cultures, but expressed by hESC. These results indicate that human cardiomyocyte differentiation is accompanied by specific changes in the expression and accumulation of ECM components and suggest a role for versican and hyaluronan in this process. J. Cell. Biochem. 111: 585–596, 2010. © 2010 Wiley‐Liss, Inc.
Synthesis and antimicrobial activity of novel 1,3,4‐oxadiazolyl‐quinazolin‐4(3H)ones
Authors: Patel Navin B. , Patel Jaymin C.
Published: June 2010

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A series of 1,3,4‐oxadiazolyl‐quinazolin‐4(3H)ones have been synthesized using known methods. All the compounds have been established on basis of elemental analysis, IR and NMR spectral data. The in vitro antimicrobial screening of the synthesized compounds were carried out against two gram‐positive bacteria (S. aureus, S. pyogenes), two gram‐negative bacteria (E. coli, P. aeruginosa), and three fungal species (C. albicans, A. niger, A. clavatus) using the broth microdilution method. The compounds 7d, 7g, 7l, 7o, 7p, and 7r possessed pronounced antibacterial activity whereas compound 7p exhibited promising antifungal activity. J. Heterocyclic Chem., (2010).
Synthesis of novel tricyclic 4‐chloro‐7,8,10,11‐tetrahydro‐5H‐benzo[e]pyrimido[4,5‐b][1,4]diazepin‐9(6H)‐ones
Authors: Xiang Jinbao , Zheng Lianyou , Zhu Tong , Dang Qun , Bai Xu
Published: June 2010

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A series of tricyclic 7,8,10,11‐tetrahydro‐5H‐benzo[e]pyrimido[4,5‐b][1,4]diazepin‐9(6H)‐ones were prepared in moderate to high yields using TFA‐promoted iminium‐cyclization reactions of 3‐(6‐(butylamino)‐4‐chloropyrimidin‐5‐ylamino)cyclohex‐2‐enones and various aldehydes. J. Heterocyclic Chem., (2010).
Preparation of 2,4,5‐triarylimidazol‐4‐ols and their stereoselective rearrangement by 1,5‐phenyl migration
Authors: Lu Gonghao , Katoh Akira , Zhang Zhiqiang , Hu Zhizhi , Lei Peng , Kimura Masaru
Published: June 2010

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Lophine hydroperoxides underwent base‐triggered 1,5‐phenyl migration in DMSO to afford imidazolones in high yields, instead of amidines with chemiluminescence (CL). The corresponding imidazolols were believed to intermediates and they were successfully obtained by treating the peroxides with DMSO without the base. The diminished CL was because of the reduction of the hydroperoxides with DMSO. The imidazolols subsequently underwent smooth base‐mediated rearrangement to afford imidazolones. Furthermore, the chiral imidazolols provided stereoselective imidazolones in high enantiomeric excess (>92%), which supported the mechanism of an intramolecular ring for the migration. J. Heterocyclic Chem., (2010).
Pressurized liquid extraction and GC‐MS analysis for simultaneous determination of seven components in Cinnamomum cassia and the effect of sample preparation
Authors: Lv Guang‐Ping , Huang Wei‐Hua , Yang Feng‐Qing , Li Jing , Li Shao‐Ping
Published: June 2010

A pressurized liquid extraction and GC‐MS method was developed for simultaneous quantitative determination of the seven components, including cinnamaldehyde, copaene, cinnamic acid, coumarin, 2‐methoxycinnamaldehyde, 2‐methoxycinnamic acid and safrole in Cinnamomum cassia. The results showed that methanol and ethanol was not available for extraction of cinnamaldehyde and 2‐methoxycinnamaldehyde due to aldol reaction. The developed method was validated to be sensitive, accurate and simple, and was successfully employed for the analysis of 15 samples of C. cassia. The contents of the investigated components were significantly variant and cinnamaldehyde is the most abundant compound, but safrole was not detected in all samples.
Smoker's nose: Structural and functional characteristics
Authors: Kjaergaard Thomas , Cvancarova Milada , Steinsvaag Sverre K.
Published: June 2010

Objectives/Hypothesis:

The effects of smoking on endonasal geometry and airflow remain largely unknown. Our study examined the relationship between smoking status and objective measures of nasal cavity dimensions, nasal congestion, and nasal airflow, using acoustic rhinometry (AR) and peak nasal inspiratory flow (PNIF).

Study Design:

Cross‐sectional study.

Methods:

Included in the study were 2,523 consecutive patients referred for evaluation of chronic nasal or sleep‐related complaints. Smoking history was recorded, and AR and PNIF were measured at baseline and after decongestion of the nasal mucosa. Minimal cross‐sectional areas (MCA), nasal cavity volumes (NCV), and PNIF, as well as quantified reversible mucosal congestion based on nasal congestion indexes (NCI) were analyzed to reveal possible associations with smoking status. Linear and logistic regressions were applied adjusting for possible confounders.

Results:

Smokers exhibited lower values of MCA, NCV, and PNIF than nonsmokers, both at baseline and after decongestion. Further, smokers had a lower decongestive capacity of the nasal mucosa, reflected by lower NCI for AR measures. Cigarette consumption, expressed as either pack‐years or cigarettes smoked per day, showed a similar inverse relationship with the rhinometric measures even though a linear dose‐response relationship could not be established.

Conclusions:

We have clearly demonstrated that smokers exhibit lower MCA and NCV, achieve lower PNIF values, and have a less‐compliant nasal mucosa than nonsmokers. Our results are unique, and provide evidence that smoking has adverse effects on the nasal airway, possibly due to mucosal inflammation. This might have further implications because altered nasal function could compromise the lower airways. Laryngoscope, 2010
Familial aggregation of olfactory impairment and odor identification in older adults
Authors: Raynor Laura A. , Pankow James S. , Cruickshanks Karen J. , Schubert Carla R. , Miller Michael B. , Klein Ronald , Huang Guan‐Hua
Published: June 2010

Objectives/Hypothesis:

The objective of this analysis was to estimate the genetic contributions to olfactory impairment.

Study Design:

Population based.

Methods:

Olfactory impairment was measured using the San Diego Odor Identification Test at the 5‐year follow‐up examination for the population‐based Epidemiology of Hearing Loss study. Subjects were classified as impaired if they correctly identified fewer than six out of eight odorants. To reduce confounding by age, analysis was restricted to subjects who were 60 to 79 years of age. Familial aggregation was evaluated by heritability estimates, tetrachoric correlations, and odds ratios in 207 sibling pairs from 135 sibships.

Results:

The prevalence of olfactory impairment was 20.2% overall and was higher in men. After adjustment for sex, age, and smoking, heritability of olfactory impairment was moderate (h2 = 0.55), although not statistically significantly different from 0 (P = .09). By contrast, the adjusted heritability estimate for bubble gum, one of the individual odorants, was significant (h2 = 0.51; P = .01).

Conclusions:

Genetic factors might contribute to general olfactory impairment in older adults, but the strength of familial aggregation differs for individual odorants, a finding consistent with prior research. Laryngoscope, 2010
Liver ischemia/reperfusion injury: Processes in inflammatory networks—A review
Authors: Abu-Amara Mahmoud , Yang Shi Yu , Tapuria Niteen , Fuller Barry , Davidson Brian , Seifalian Alexander
Published: June 2010

Liver ischemia/reperfusion (IR) injury is typified by an inflammatory response. Understanding the cellular and molecular events underpinning this inflammation is fundamental to developing therapeutic strategies. Great strides have been made in this respect recently. Liver IR involves a complex web of interactions between the various cellular and humoral contributors to the inflammatory response. Kupffer cells, CD4+ lymphocytes, neutrophils, and hepatocytes are central cellular players. Various cytokines, chemokines, and complement proteins form the communication system between the cellular components. The contribution of the danger-associated molecular patterns and pattern recognition receptors to the pathophysiology of liver IR injury are slowly being elucidated. Our knowledge on the role of mitochondria in generating reactive oxygen and nitrogen species, in contributing to ionic disturbances, and in initiating the mitochondrial permeability transition with subsequent cellular death in liver IR injury is continuously being expanded. Here, we discuss recent findings pertaining to the aforementioned factors of liver IR, and we highlight areas with gaps in our knowledge, necessitating further research. Liver Transpl 16:1016-1032, 2010. © 2010 AASLD.
Portopulmonary hypertension: Diagnostic advances and caveats
Authors: Krowka Michael J.
Published: June 2010

Portopulmonary hypertension represents a major risk factor for transplantation; therefore, preoperative detection is crucial. The aims of this study were to determine (1) whether Doppler echocardiography performed at evaluation is a reliable tool for detecting portopulmonary hypertension and (2) the incidence of acquired portopulmonary hypertension profile after evaluation. One hundred sixty-five patients had Doppler echocardiography and right heart catheterization at evaluation over a 9-year period. All patients had a prospective follow-up, and the results of catheterization at evaluation were compared with those obtained at the time of transplantation. Seventeen of 165 patients met the criteria for portopulmonary hypertension on Doppler echocardiography. Portopulmonary hypertension was confirmed by catheterization in 10 patients and ruled out in 7. There were no false negatives for echocardiography. Mean pulmonary artery pressure was significantly higher during the initial phase of transplantation than at evaluation (17.8 ± 4.3 versus 20.3 ± 5.5 mm Hg, respectively, P < .0001), and there was no significant correlation between values obtained at these 2 time points. Three patients showed to have acquired portopulmonary hypertension profile although waiting for a graft within time intervals ranging from 2.5 to 5 months. In conclusion, Doppler echocardiography is a highly sensitive tool for detecting portopulmonary hypertension. However, because this technique has a poor positive predictive value, right heart catheterization is recommended for confirming portopulmonary hypertension. In addition, the absence of portopulmonary hypertension at evaluation does not exclude the occasional occurrence of acquired portopulmonary hypertension profile after listing.
Cost effectiveness and application of online monitoring in reinforced concrete structures
Authors: Schiegg Y. , Steiner L.
Published: June 2010

The annual costs for the maintenance of the Swiss national road networks amount to SFr. 560–640 millions 1. Due to the limited means and the large number of engineering structures at the critical age between 30 and 45 years cost‐effective solutions for the monitoring and the maintenance of these structures have to be found 2. In this paper the life cycle costs of an engineering structure using a sensor network (online‐monitoring system) were investigated. These costs were compared to the costs of classical inspection techniques.
Alkynyl Ethers of Glucans: Substituent Distribution in Propargyl‐, Pentynyl‐ and Hexynyldextrans and ‐amyloses and Support for Silver Nanoparticle Formation
Authors: Tahir M. Nazir , Bork Christian , Risberg Anna , Horst Jennifer C. , Komoß Christina , Vollmer Antje , Mischnick Petra
Published: June 2010

Alkynyldextrans with a DS in the range 0.1–1.67 have been prepared as reactive intermediates for further polymer‐analogous functionalisation. DS and substituent distribution were determined by GLC and GLCMS after hydrolysis and acetylation, or methanolysis and trimethylsilylation. Reactivity was in the order O‐2 > O‐4 ≥ O‐3 with pronounced differences in the distinct patterns for propargyl ethers and its higher homologous. A large deviation from a random substituent distribution was observed. Propargyldextrans were not stable during long‐time storage in the solid state, while terminal pentynyl and hexynyl ethers are. Pentynyldextrans showed structure formation of various geometries. They bound silver efficiently, yielding silver nanoparticles by reduction.

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Delivery of Anticancer Drugs Using Polymeric Micelles Stabilized by Hydrogen‐Bonding Urea Groups
Authors: Tan Jeremy P. K. , Kim Sung Ho , Nederberg Fredrik , Fukushima Kazuki , Coady Daniel J. , Nelson Alshakim , Yang Yi Yan , Hedrick James L.
Published: June 2010

Polymeric micelles comprising a hydrogen‐bonding core were formed from block copolymers with pendant urea groups and explored as drug delivery vehicles. The amphiphilic block copolymers were synthesized by organocatalytic ring opening polymerization (ROP) of urea‐functionalized cyclic carbonates from a poly(ethylene glycol) macroinitiator. The urea functionality was incorporated because its ability to increase the hydrophobic core's affinity toward polar organic compounds through intermolecular hydrogen bonding. Doxorubicin (DOX), a lipophilic anticancer drug with hydrogen‐bonding functionalities, was systematically incorporated into the micelle's hydrophobic interior via hydrogen bonding to the functionalized monomers. Micelles employing urea groups were found to more efficiently interact with DOX thus allowing increased drug loading capacity while maintaining a desirable micellular size. More importantly, while DOX‐loaded micelles were shown to kill HepG2 human liver carcinoma cell lines efficiently, all of the polymers were non‐cytotoxic.

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Tuning the Properties of Functional Pyrrolidinium Polymers by (Co)polymerization of Diallyldimethylammonium Ionic Liquids
Authors: Jovanovski V. , Marcilla R. , Mecerreyes David
Published: June 2010

The synthesis and polymerization of novel diallyldimethylammonium ionic liquid monomers is described. A free‐radical polymerization follows a ring‐closing cyclopolymerization mechanism similar to the one observed previously for diallyldimethylammonium halides that leads to pyrrolidinium functional polymers. As previously observed in other families of polymeric ionic liquids, their physico‐chemical properties are seriously affected by the nature of the counter‐anion. As an example, the thermal stability increases following the trend SCN− < ${\rm BF}_{4}^{ - }$ < ${\rm PF}_{6}^{ - }$ < bis(trifluoromethane)sulfonamide. Interestingly, this polymerization route may lead to the synthesis of a new family of random copolymers that have a similar poly(diallyldimethylammonium) backbone and a mixture of counter‐anions determined by the comonomer selection.

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To compact branch‐line couplers using parallel high‐impedance transmission lines
Authors: Khalaj‐Amirhosseini Mohammad , Yazdani Mohammad
Published: June 2010

In this article, a new way is proposed to compact the transmission lines of microstrip devices such as branch‐line couplers (BLCs).In this way, two unequal‐length high‐impedance (thin) transmission lines paralleling with each other are used instead of a single transmission line. The shorter and greater lines can be implemented in a right and meander forms, respectively. The usefulness of the proposed way was verified by designing, simulation, and fabrication of a compacted BLC at frequency 2 GHz. An area compactness of about 64.2% is achieved. © 2010 Wiley Periodicals, Inc. Microwave Opt Technol Lett 52: 1996–1999, 2010; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.25369
A tunable dual‐band branch line coupler based on composite right/left‐handed transmission lines
Authors: Park Jinsung , Lee Yongshik
Published: June 2010

This article demonstrates a frequency‐tunable dual‐band branch line coupler based on composite right/left‐handed transmission lines.A simple, yet effective conversion enables to design such transmission lines in a form that can be frequency tuned. A tuning function is realized with varactors. For demonstration, a dual‐band branch line coupler at 0.6 and 1.2 GHz is fabricated. Tuning ranges of 51.4 and 18.0% are measured in the lower and upper band, respectively, in which |S21/S31| ≤ ±0.5 dB is obtained, when maintaining S11 below −10 dB. © 2010 Wiley Periodicals, Inc. Microwave Opt Technol Lett 52: 1955–1958, 2010; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.25373
A 60‐GHz LNA with 18.6‐dB gain and 5.7‐dB NF in 90‐nm CMOS
Authors: Kang Kai , Brinkhoff James , Lin Fujiang
Published: June 2010

A 60‐GHz low‐noise amplifier (LNA) is implemented in a commercial 90‐nm RF CMOS process. A scalable model based on electromagnetic simulation is adopted to model on‐chip microstrip transmission lines. First‐pass silicon success has been achieved by accurate modeling of passive and active devices and careful layout. The three‐stage LNA achieves 18.6‐dB gain, a noise figure of 5.7 dB, and an input P1dB of −14.8 dBm. It consumes 24 mA from a 1.2‐V supply. The total LNA die area with pads is 1.4 × 0.5 mm2. © 2010 Wiley Periodicals, Inc. Microwave Opt Technol Lett 52: 2056–2059, 2010; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.25379
Experimental observation of photo‐excited electron depletion for stability improvement in a lithium niobate polarization converter
Authors: Twu Ruey‐Ching , Lee Hsuan‐Hsien , Hong Hao‐Yang
Published: June 2010

The relations between conversion stabilities and photo‐excited electron‐depletion effects have been experimentally evaluated in a Zn‐indiffused lithium niobate polarization converter, for the first time.A simple method with a biased voltage and laser trimming was performed to observe these phenomena. The results show that the stable conversions for both polarities of applied polarization‐conversion voltages are achievable due to the depletion of photo‐excited electrons in the waveguides. © 2010 Wiley Periodicals, Inc. Microwave Opt Technol Lett 52: 1937–1941, 2010; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.25384
Effect of gain medium on the performance of Brillouin fiber laser
Authors: Ahmad H. , Parvizi R. , Shahabuddin N.S. , Yusoff Z. , Harun S.W.
Published: June 2010

The performance of single‐wavelength Brillouin fiber lasers (BFLs) is investigated for different gain medium.An efficient BFL is demonstrated using a piece of 100‐m‐long PCF as the gain medium. The BFL provides a peak power of 0 dBm and a side mode suppression ratio of more than 30 dB with the threshold power of 8.5 dBm for the BFL generation. However, the threshold is much lower for the BFL configured with 20 km long non‐zero dispersion shifted fiber, which has a smaller core size. With this fiber, the threshold power of the BFL is obtained at 5 dBm, and this power increases with the shorter length of the gain medium. © 2010 Wiley Periodicals, Inc. Microwave Opt Technol Lett 52: 2158–2160, 2010; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.25386
Improved MOM‐PO hybrid method for analyzing antenna around nurbs scatterer
Authors: Huang Kai , He Zhi‐Li , Liang Chang‐Hong
Published: June 2010

A new efficient technique for analyzing disturbed pattern of antenna around nonuniform rational B‐spline scatterer is proposed in this article, termed the hybrid method of moments and physical‐optics (MOM‐PO) technique. The integral of PO currents is calculated by using Ludwig integral, which solves the invalidation when the distance between antenna and scatterer is less than one wavelength mentioned in literatures before. The relative pattern obtained using this method is compared with the patterns obtained from the previous solution and MOM. The pattern of the presented method agrees more closely with that of MOM, which demonstrates the accuracy of this approach. The outstanding advantage is that the present approach is applicable without restrictions on the distance between the antenna and the surface. © 2010 Wiley Periodicals, Inc. Microwave Opt Technol Lett 52: 2049–2053, 2010; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.25392
Design of dual‐frequency circularly‐polarized slot antennas with switchable frequency
Authors: Hsieh Tsung‐Hsun , Row Jeen‐Sheen
Published: June 2010

A reconfigurable design for circularly‐polarized (CP) slot antennas with dual‐frequency operation is presented in this article.The proposed antenna structure is composed of an annular‐ring slot, fed by an L‐shaped strip, and four parasitic patches, symmetrically placed along the circumference of the ring slot. The slot antenna operates at a one‐wavelength resonant mode, and its resonant frequency has a noticeable reduction with increasing the dimensions of the parasitic patches. Furthermore, while the resonant frequency is decreased, both good CP radiation and impedance matching can be simultaneously obtained as long as the open‐stub length of the L‐shaped strip is properly selected. For the proposed antenna, the effects of various parasitic‐patch dimensions on resonant frequency are investigated, and the obtained results indicate that the resonant frequency ranges between 1050 and 1665 MHz as the length of the parasitic patches is changed. Therefore, a CP antenna with the capability of switching between two operating frequencies can be realized by employing diodes to reconfigure the length of the parasitic patches. A prototype designed for the dual‐frequency operation (L1/L2) of the Global Positioning System is implemented. Details of the antenna designs and experimental results are presented and discussed. © 2010 Wiley Periodicals, Inc. Microwave Opt Technol Lett 52: 2023–2029, 2010; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.25396
Reconfigurable ultra‐wideband slot antenna
Authors: Kelly James R. , Hall Peter S.
Published: June 2010

This article presents a reconfigurable uniplanar printed slot antenna with eight microwave switches, it is possible to reconfigure the impedance bandwidth, of the antenna between three discrete states (two ultra‐wide band and one narrowband).© 2010 Wiley Periodicals, Inc. Microwave Opt Technol Lett 52: 1988–1990, 2010; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.25398
Compact interdigital microstrip band pass filter
Authors: Cheng Jin , Alphones Arokiaswami
Published: June 2010

A compact microstrip band pass filter using interdigital coupled line and meandered electromagnetic band gap (EBG) slots is proposed in this article. The interdigital capacitor in the signal strip with meander EBG slots etched in the ground plane contributes to the series capacitance. In addition, the finger of the interdigital is shorted to ground through via holes, which results in the shunt inductance. The combination of series capacitor and shunt inductor is useful to realize the left‐handed metamaterial and improve the frequency selectivity. The filter, which is composed by cascading two units, has a resonant frequency of 2.8 GHz and a fractional 3 dB band width of 28.6% (2.4–3.2 GHz). A return loss of 18 dB and a maximum of 1.6 dB insertion loss in the pass‐band are achieved. The filter size is 11.2 × 4.00 mm2, which is 0. 172 λg × 0.06 λg, and the length of resonator is 5.6 mm, which is 0.086 λg, where λg = 65 mm is the guided wavelength at center frequency. © 2010 Wiley Periodicals, Inc. Microwave Opt Technol Lett 52: 2128–2132, 2010; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.25403
A coaxial fed flower shaped multi‐element suspended patch antenna with illumination area in the form of a ring
Authors: Shekhar T.K. Chandra , Bhat B.
Published: June 2010

A multi‐element suspended microstrip patch antenna with flower shaped printed pattern excited at its centre by a coaxial feed is presented. All the radiating patch elements are electromagnetically coupled symmetrically to the same coaxial feed, thereby eliminating the need for a separate power division network. With three or more elements, the antenna beam illuminates an area in the form of a ring symmetric about the axis perpendicular to the plane of the patch elements. The antenna offers a gain in the range 5–6 dBi with a 3 dB beamwidth of about 50° in any cross‐sectional plane passing through the vertical axis. Details of the simulation studies carried out on the antenna with one to five elements and experimental results on the fabricated antennas are presented. The antenna has potential applications in remote sensing and biomedical areas, particularly for microwave imaging. © 2010 Wiley Periodicals, Inc. Microwave Opt Technol Lett 52: 2037–2043, 2010; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.25418
Compact narrow band‐pass filter with λG/4 short stubs using impedance mismatching of the transmission line
Authors: Yoon Ki‐Cheol , Kim Jeonggon Harrison , Lee Jong‐Chul
Published: June 2010

In this article, a narrow band pass filter with reduced size using the λg/4 short stubs is presented.The filter size is reduced by realization of transmission line at the second harmonic while the power can be transferred to the output using the fundamental frequency band generated in the resonator and the transmission line in which the impedance mismatching technique is adopted. The experimental results show that the insertion loss is 2.0 dB and return loss is 11.1 dB, and the fractional bandwidth is 10% at the center frequency of 5.8 GHz. The filter size is 19.7 × 8.6 mm2. © 2010 Wiley Periodicals, Inc. Microwave Opt Technol Lett 52: 2002–2005, 2010; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.25419
Echo planar correlated spectroscopic imaging: Implementation and pilot evaluation in human calf in vivo
Authors: Lipnick Scott , Verma Gaurav , Ramadan Saadallah , Furuyama Jon , Thomas M. Albert
Published: June 2010

Exploiting the speed benefits of echo‐planar imaging (EPI), the echo‐planar spectroscopic imaging (EPSI) sequence facilitates recording of one spectral and two to three spatial dimensions faster than the conventional magnetic resonance spectroscopic imaging (MRSI). A novel four dimensional (4D) echo‐planar correlated spectroscopic imaging (EP‐COSI) was implemented on a whole body 3 T MRI scanner combining two spectral with two spatial encodings. Similar to EPSI, the EP‐COSI sequence used a bipolar spatial read‐out train facilitating simultaneous spatial and spectral encoding, and the conventional phase and spectral encodings for the other spatial and indirect spectral dimensions, respectively. Multiple 2D correlated spectroscopy (COSY) spectra were recorded over the spatially resolved volume of interest (VOI) localized by a train of three slice‐selective radiofrequency (RF) pulses (90°–180°–90°). After the initial optimization using phantom solutions, the EP‐COSI data were recorded from the lower leg of eight healthy volunteers including one endurance trained volunteer. Pilot results showed acceptable spatial and spectral quality achievable using the EP‐COSI sequence. There was a detectable separation of cross peaks arising from the skeletal muscle intramyocellular lipids (IMCLs) and extramyocellular lipids (EMCLs) saturated and unsaturated pools. Residual dipolar interaction between the N‐methylene and N‐methyl protons of creatine/phosphocreatine (Cr/PCr) was also observed in the tibialis anterior region. Magn Reson Med, 2010. © 2010 Wiley‐Liss, Inc.
RF excitation using time interleaved acquisition of modes (TIAMO) to address B1 inhomogeneity in high‐field MRI
Authors: Orzada Stephan , Maderwald Stefan , Poser Benedikt Andreas , Bitz Andreas K. , Quick Harald H. , Ladd Mark E.
Published: June 2010

As the field strength and, therefore, the operational frequency in MRI is increased, the wavelength approaches the size of the human head/body, resulting in wave effects, which cause signal decreases and dropouts. Several multichannel approaches have been proposed to try to tackle these problems, including RF shimming, where each element in an array is driven by its own amplifier and modulated with a certain (constant) amplitude and phase relative to the other elements, and Transmit SENSE, where spatially tailored RF pulses are used. In this article, a relatively inexpensive and easy to use imaging scheme for 7 Tesla imaging is proposed to mitigate signal voids due to B field inhomogeneity. Two time‐interleaved images are acquired using a different excitation mode for each. By forming virtual receive elements, both images are reconstructed together using GRAPPA to achieve a more homogeneous image, with only small SNR and SAR penalty in head and body imaging at 7 Tesla. Magn Reson Med, 2010. © 2010 Wiley‐Liss, Inc.
Cystic fibrosis related diabetes
Authors: Alexander S , Bridges N
Published: June 2010

Cystic fibrosis related diabetes is the most common co‐morbidity in cystic fibrosis. Insulin deficiency is the key factor in the development of cystic fibrosis related diabetes, which is associated with worse pulmonary and nutritional morbidity and increased mortality.

The oral glucose tolerance test remains standard for screening, but continuous glucose monitoring systems are increasingly used to help with screening and management.

Insulin is the only treatment with evidence of benefit. The timing of insulin treatment, and the level of glycaemia for which to aim, are areas which need further research.

Treatment is aimed at both optimising nutrition and lung function and reducing the risk of microvascular complications. Copyright © 2010 John Wiley & Sons.
Validation of the mPW1PW Quantum chemical calculations for the vibrational study of organic molecules – re‐assignment of the isopropylamine vibrational spectra
Authors: Padrão Sara , Fiuza Sónia M. , Amado Ana M. , Amorim da Costa António M. , Batista de Carvalho Luis A. E.
Published: June 2010

The validity of the mPW1PW91 density functional theory (DFT) method coupled to the all‐electron basis set 6‐31G* (mPW1PW/6‐31G*) for the study of amines, using isopropylamine (iPram) as a case study, was evaluated. Validation was performed by comparing the calculated values with the corresponding experimental results obtained and/or reported in the literature. Moreover, the accuracy of that theoretical level was compared with that of other widely used theoretical levels, namely HF/6‐31G*, B3LYP/6‐31G* and MP2/6‐31G*. The effect of basis set improvement within the mPW1PW protocol was evaluated considering the widely used 6‐311G** basis set. On the whole, the results clearly show that the mPW1PW/6‐31G* calculations are a suitable tool for the prediction of the structural and vibrational features of iPram. The validation of the theoretical methodology allowed a complete revision of the vibrational assignments previously reported in the literature, being the result of several proposed re‐assignments. Copyright © 2010 John Wiley & Sons, Ltd.
An Open Argon Dielectric Barrier Discharge VUV‐Source
Authors: Sobottka Axel , Drößler Lutz , Lenk Martin , Prager Lutz , Buchmeiser Michael R.
Published: June 2010

An argon vacuum ultra violet (VUV) light lamp was built. The radiation source is driven by an RF generator in continuous wave (cw) mode at frequencies of 680 and 840 kHz, respectively. An optimum design was developed for an atmospheric pressure glow discharge in an open system. The UV power of the radiation source was measured and the time response of the dielectric discharge was investigated. Finally, the emission spectra were measured under different conditions. All components of the lamp were designed in way that they meet the requirements for a practical setup for the irradiation of miscellaneous samples for both surface modification and activation.

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Recent developments in linear and nonlinear near‐field microscopy on single plasmonic nanoparticles
Authors: Duò Lamberto , Biagioni Paolo , Finazzi Marco
Published: June 2010

Plasmonic circuits constituted of several interacting optical elements require new means to characterize their response down to the single particle level, both in amplitude and phase. To this aim, scanning near‐field optical microscopy (SNOM) allows for sub‐diffraction resolution, but requires a deep understanding of the physical processes at the basis of image formation. In this paper, we briefly review recent developments in the linear and nonlinear near‐field characterization of single plasmonic resonators. On the one hand, linear scattering processes are governed by interference between light propagating out of the SNOM aperture and that radiated by the plasmonic scatterer, thus bearing signatures of both amplitude and phase of the particle response. On the other hand, nonlinear investigations are dominated by local field enhancements, and are thus best suited to image the spatial distribution of the plasmon modes sustained by the resonator. The combined use of the two techniques, therefore, allows for a complete analysis of both the scattering response and the local field distribution near resonant plasmonic nanoparticles.
Optical properties of nanostructured metamaterials
Authors: Cortes Ernesto , Mochán Luis , Mendoza Bernardo S. , Ortiz Guillermo P.
Published: June 2010

We present a very efficient recursive method to calculate the effective optical response of nanostructured metamaterials made up of particles with arbitrarily shaped cross sections arranged in periodic two‐dimensional arrays. We consider dielectric particles embedded in a metal matrix with a lattice constant much smaller than the wavelength. Neglecting retardation our formalism allows factoring the geometrical properties from the properties of the materials. If the conducting phase is continuous the low frequency behavior is metallic. If the conducting paths are nearly bloqued by the dielectric particles, the high frequency behavior is dielectric. Thus, extraordinary‐reflectance bands may develop at intermediate frequencies, where the macroscopic response matches vacuum. The optical properties of these systems may be tuned by adjusting the geometry.

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Sketch of a nanostructured metamaterial slab with a dielectric‐like or metallic‐like behavior depending on the frequency of the incoming light.
Theory of the temperature dependent dielectric function of semiconductors: from bulk to surfaces. Application to GaAs and Si
Authors: Shkrebtii Anatoli I. , Ibrahim Zahraa A. , Teatro Timothy , Richter Wolfgang , Lee Martin J.G. , Henderson Laura
Published: June 2010

A novel, efficient method for calculating the temperature dependencies of the linear dielectric functions of semiconductor systems and its application are presented. The method follows an intuitive and natural path withab‐initiofinite temperature molecular dynamics providing the thermally perturbed atomic configurations, which are used as structural inputs for calculating the dielectric function. The effect of lattice dynamics, including quantum zero point vibration, on the electronic bands and dielectric function of crystalline (c‐) GaAs and Si as well as hydrogenated amorphous Si (a‐Si:H) is discussed. Our theoretical results for bulk c‐GaAs and c‐Si in the range from 0 to 1000 K are in good overall agreement with highly accurate ellipsometric measurements. The implementation of the method resolves a serious discrepancy in energy and line shape between experiment and the latest optical models, all of which neglect lattice dynamics, and provides information on the indirect gap and indirect optical transitions in c‐Si. For a‐Si:H, the calculated temperature dependent optical response combined with the vibrational spectroscopy provides detailed insight into electronic, dynamical properties, and stability of this important prototypical amorphous semiconductor material. At semiconductor surfaces, dynamical effects are expected to be even more pronounced due to reduced atom coordination and reconstruction. This is demonstrated for C(111) 2 × 1, an intensively studied but controversial surface of the quantum diamond crystal.
Vibrational properties of sp carbon atomic wires in cluster‐assembled carbon films
Authors: Onida Giovanni , Manini Nicola , Ravagnan Luca , Cinquanta Eugenio , Sangalli Davide , Milani Paolo
Published: June 2010

Linear chains made by a single row of sp‐hybridized carbon are predicted to display fascinating mechano‐electronic properties connected with their termination and stabilization inside realistic carbon structures. The present work describes how the computed vibrational properties of cumulenic and polyynic carbon chains allow one to interpret the carbynic features observed in Raman spectra of cluster‐assembled sp–sp2 films. The overall picture is consistent with the measured decay of the components induced by air or oxygen exposure.

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The electronic properties of carbon atomic chains attached to the edges of graphitic fragments can be controlled by a relative twist of the terminating planes.
A slave‐boson mean‐field theory for general multi‐band Hubbard models
Authors: Bünemann J.
Published: June 2010

We introduce a new slave‐boson mean‐field theory which allows the investigation of general multi‐band Hubbard models. Unlike earlier attempts of such a generalization, in our approach the quantum‐mechanical problem is exactly reformulated in an extended Hilbert space of Fermions and Bosons before a mean‐field approximation is applied. Systems with superconducting order parameters are naturally included in our formalism. Our ground‐state energy functional agrees with the corresponding quantity derived within the Gutzwiller theory.
Electrical properties of C60 delta‐doped GaAs and AlGaAs layers grown by MBE
Authors: Nishinaga Jiro , Hayashi Takashi , Hishida Kiyoshi , Horikoshi Yoshiji
Published: June 2010

C60 δ‐doped GaAs and AlGaAs layers are grown by migration enhanced epitaxy method. Sticking coefficients of C60 on GaAs and AlGaAs surfaces and electrical characteristics of the layers are investigated by secondary ion mass spectroscopy (SIMS) and electrochemical capacitance voltage (ECV) measurements. SIMS profiles indicate that the layers have well‐defined δ‐doped structures, and the sticking coefficients of C60 on GaAs and AlGaAs surfaces are confirmed to be sufficiently high. ECV profiles of C60 δ‐doped GaAs and AlGaAs layers suggest that C60 molecules in GaAs and AlGaAs lattices produce electron traps which can be charged or discharged by applied electric fields. (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Atomic layer epitaxy of AlGaN
Authors: Nagamatsu Kentaro , Iida Daisuke , Takeda Kenichiro , Nagata Kensuke , Asai Toshiaki , Iwaya Motoaki , Kamiyama Satoshi , Amano Hiroshi , Akasaki Isamu
Published: June 2010

Atomic layer epitaxy of AlGaN with an average growth rate of as high as 4.5 mm/h has been achieved by the high‐speed switching‐valves (HSSVs) technique in a raised‐pressure metalorganic vapor phase epitaxy system. Regarding the duration of group III metalorganics and NH3 gases input, 0.1 second for each injection time is found to be sufficient to realize AlGaN growth of one monolayer per cycle over a 2‐inch wafer with hydrogen and nitrogen carrier gases at a raised pressure. Low‐temperature growth of high‐quality AlGaN has been achieved using HSSVs. (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)