bluuebunny/crossref_metadata_2025 huggingface dataset:
Using toxicity testing to evaluate electrochemical reactor operations
Authors: Saylor Greg L. , Chen Linxi , Kupferle Margaret J.
Published: December 2011

In the present study, the Microtox® test was used to track the toxicity of electrochemical effluents to the marine bacteria Vibrio fischeri as a function of reaction time. When electrochemistry was used to degrade aqueous phenol using different reactor configurations, two reaction pathways were identified, chlorine substitution and oxidation, depending on whether the electrolyte contained chloride. For a boron-doped diamond (BDD) anode, electrochemistry using Na2SO4 electrolyte produced a significantly more toxic effluent than when using NaCl electrolyte with all other conditions remaining the same. This effect is attributed to the reaction pathway, specifically the production of benzoquinone. Benzoquinone was produced only during electrochemistry using Na2SO4 and is the most toxic potential intermediate, having nearly 800 times more toxicity than phenol. Although the use of NaCl produced a lower toxicity effluent than Na2SO4, caution should be observed because of the production of chlorinated phenols, which can be of special environmental concern. When comparing graphite rod and BDD plate anodes in terms of toxicity evolution when using Na2SO4, BDD was found to produce a lower toxicity effluent; this is a result of the increased oxidizing power of BDD, reducing the formation of benzoquinone. In this comparison, the type of anode material/electrode configuration did not seem to affect which intermediates were detected but did affect the quantity of and rate of production of intermediates. Environ. Toxicol. Chem. 2012;31:494–500. © 2011 SETAC
Molluscicidal activity of crude water and hexane extracts of Hypericum species to snails (Radix peregra)
Authors: Teixeira Tânia , Rainha Nuno , Rosa José Silvino , Lima Elisabete , Baptista José
Published: December 2011

In spite of intense research on both chemical constituency and biological activity of Hypericum species, potential applications of their active components for pest control have been less well investigated. In the present study, Hypericum androsaemum (tutsan), Hypericum foliosum (malfurada), and Hypericum undulatum (wavy St. John's wort) aqueous and hexane extracts were studied for their molluscicidal and ovicidal activities against Radix peregra. The molluscicidal activity of the aqueous extracts was low, except for H. androsaemum infusion (median lethal concentration [LC50]adults = 317.1 ppm; LC50juveniles = 415 ppm), and less important compared with the toxicity of all three hexane extracts tested: H. androsaemum (LC50adults = 30.47 ppm; LC50juveniles = 73.25 ppm), H. undulatum (LC50adults = 30.55 ppm; LC50juveniles = 60.54 ppm), and H. foliosum (LC50adults = 48.61 ppm; LC50juveniles = 38.81 ppm). An ovicidal effect was observed only with H. androsaemum infusion (1.85% of hatching at 500 ppm) and H. foliosum hexane extract (0.0% of hatching at 100 ppm). A preliminary phytochemical investigation of the lipophylic extracts from these Hypericum sp. revealed a different chemical profile and confirmed the presence of ursolic acid only in H. undulatum as the main compound. The present study indicates that products from hexane extracts of the Hypericum sp. analyzed may be used as potential molluscicides to control snails responsible for transmitting fasciolosis. Environ. Toxicol. Chem. 2012;31:748–753. © 2011 SETAC
Malpractice claims following screening mammography in The Netherlands
Authors: van Breest Smallenburg Vivian , Setz‐Pels Wikke , Groenewoud Johanna H. , Voogd Adri C. , Jansen Frits H. , Louwman Marieke W.J. , Tielbeek Alexander V. , Duijm Lucien E.M.
Published: December 2011

Although malpractice lawsuits are frequently related to a delayed breast cancer diagnosis in symptomatic patients, information on claims at European screening mammography programs is lacking. We determined the type and frequency of malpractice claims at a Dutch breast cancer screening region. We included all 85,274 women (351,009 screens) who underwent biennial screening mammography at a southern breast screening region in The Netherlands between 1997 and 2009. Two screening radiologists reviewed the screening mammograms of all screen detected cancers and interval cancers and determined whether the cancer had been missed at the previous screen or at the latest screen, respectively. We analyzed all correspondence between the screening organization, clinicians and screened women, and collected complaints and claims until September 2011. At review, 20.9% (308/1,475) of screen detected cancers and 24.3% (163/670) of interval cancers were considered to be missed at a previous screen. A total of 19 women (of which 2, 6 and 11 women had been screened between 1997 and 2001 (102,439 screens), 2001 and 2005 (114,740 screens) and 2005 and 2009 (133,830 screens), respectively) had contacted the screening organization for additional information about their screen detected cancer or interval cancer, but filed no claim. Three other women directly initiated an insurance claim for financial compensation of their interval cancer without previously having contacted the screening organization. We conclude that screening‐related claims were rarely encountered, although many screen detected cancers and interval cancers had been missed at a previous screen. A small but increasing proportion of women sought additional information about their breast cancer from the screening organization.
The contrasting age‐incidence patterns of bone tumours in teenagers and young adults: Implications for aetiology
Authors: Arora Ramandeep S. , Alston Robert D. , Eden Tim O.B. , Geraci Marco , Birch Jillian M.
Published: December 2011

Bone tumours comprise 0.2% of cancers overall but 5.7% in 15–24 year olds. To explore the relationship with adolescence we have analysed age‐incidence patterns of bone tumours in a large national dataset. Data on incident cases of bone tumours in 0–84 year olds in England, 1979–2003, were extracted from national cancer registration data. Incidence rates per million person‐years by 5‐year age‐group, sex, morphology and primary site were calculated and adjusted to the world standard population. Nine thousand one hundred forty‐six cases were identified giving an overall age‐standardized rate of 7.19 per million person‐years. The distribution by morphology was: osteosarcoma, 34.2%; chondrosarcoma, 27.2%; Ewing sarcoma, 19.3%; other, 19.4%. The distribution varied by age. Ewing sarcoma was most common in 0–9 year olds, osteosarcoma in 10–29 year olds and chondrosarcoma in 30–84 year olds. 29.2% of all tumours occurred in 0–24 year olds. Highest incidence of osteosarcoma and Ewing sarcoma in females was in 10–14 year olds. In males, peak incidence occurred at 15–19 years and exceeded that in females. Chondrosarcoma incidence steadily increased with age. The proportions of Ewing sarcomas occurring in respective bones were consistent with those of the adult skeleton by weight. In osteosarcoma tumours of long bones of lower limb were markedly over‐represented in the adolescent peak, being six times more than at any other site. Variation in incidence patterns with age and site suggests pubertal bone growth to be a key factor in osteosarcoma while different biological pathways could be relevant for Ewing sarcoma.
Learning needs of physician assistants working in hospital medicine
Authors: Torok Haruka , Lackner Christina , Landis Regina , Wright Scott
Published: December 2011

BACKGROUND:

Hospital Medicine is growing rapidly, and the number of physician assistants (PAs) in this field is expected to grow. However, there is no available data related to the learning needs of PA hospitalists.

OBJECTIVE:

To conduct a needs assessment for PA hospitalists who may be embarking on a hospitalist career.

DESIGN:

Cross‐sectional survey based on the Core Competencies in Hospital Medicine.

SETTING/PARTICIPANTS:

A sample of hospitalist PAs working in the United States.

MEASUREMENTS:

Amount of experience with core diagnoses and procedures, preferences for additional training that would have prepared them to function as hospitalist PAs.

RESULTS:

Sixty‐nine PAs responded (response rate, 67%). Among the core clinical conditions, respondents had the most experience in managing diabetes and urinary tract infections and were least experienced with health care–associated pneumonias and sepsis syndrome. Over 90% rarely performed core competency procedures other than electrocardiogram and chest X‐ray interpretations. The top 3 content areas that PA hospitalists believed would have helped to better prepare them to care for inpatients were palliative care (percent of PAs who agreed or strongly agreed: 85%), nutrition for hospitalized patients (84%), and consultations (64%). Almost all (91%) indicated that they would have been interested in formal postgraduate hospital medicine training even if it meant having a lower stipend during the first year on the job.

CONCLUSIONS:

This is the first national data on self‐perceived learning needs of PA hospitalists. The results may prove helpful for both PAs entering hospitalist careers and for the physician groups looking to hire them. Journal of Hospital Medicine 2012;. © 2012 Society of Hospital Medicine
Erratum: Mechanical tissue optical clearing technique increases imaging resolution and contrast through Ex vivo porcine skin
Authors: Izquierdo‐Román Alondra , Vogt William C. , Hyacinth Leeanna , Rylander Christopher G.
Published: December 2011

Background and Objectives

Mechanical tissue optical clearing permits light delivery deeper into turbid tissue, which may improve current optical diagnostics and laser‐based therapeutic techniques. We investigated the effects of localized compression on brightfield imaging through ex vivo porcine skin by evaluating resolution and contrast of a target positioned beneath native, mechanically compressed, or chemically cleared specimens. We also evaluated the effects of indentation on dynamic tissue thickness and light transmission.

Study Design/Methods

A 5 mm diameter, hemispherically tipped, manual load transducer was used to compress specimens using 2–44 N for 60 seconds. Chemically cleared specimens were immersed for 1 hour in glycerol or dimethyl sulfoxide. A USAF 1951 resolution target was positioned beneath specimens and imaged using brightfield microscopy. Resolution and contrast of target features were analyzed. In separate experiments, a mechanical test instrument was used to compress and hold specimens at a final thickness while measuring applied load and light transmission.

Results

Image intensity profiles showed that while uncompressed skin did not allow resolution of any target, localized compression allowed maximum resolution (least line width) of 173 ± 21 µm. Mechanical clearing achieved up to four times higher maximum resolution and 2–3 times higher contrast sensitivity than chemical immersion. Resolving capability was highly correlated with compressive tissue strain. Light transmission increased during tissue compression, but also increased while holding final thickness constant.

Conclusion

Localized compression is an effective technique for increasing resolution and contrast of target features through tissue and may improve light‐based diagnostics. Thickness reduction and other mechanisms appear to contribute to this effect. Lasers Surg. Med. 43: 814–823, 2011. © 2011 Wiley Periodicals, Inc.
Erratum: Fiberoptic microneedles: Novel optical diffusers for interstitial delivery of therapeutic light
Authors: Kosoglu Mehmet A. , Hood Robert L. , Rossmeisl John H. , Grant David C. , Xu Yong , Robertson John L. , Rylander Marissa Nichole , Rylander Christopher G.
Published: December 2011

Background and Objectives

Photothermal therapies have limited efficacy and application due to the poor penetration depth of light inside tissue. In earlier work, we described the development of novel fiberoptic microneedles to provide a means to mechanically penetrate dermal tissue and deliver light directly into a localized target area. This paper presents an alternate fiberoptic microneedle design with the capability of delivering more diffuse, but therapeutically useful photothermal energy. Laser lipolysis is envisioned as a future clinical application for this design.

Materials and Methods

A novel fiberoptic microneedle was developed using hydrofluoric acid etching of optical fiber to permit diffuse optical delivery. Microneedles etched for 10, 30, and 50 minutes, and an optical fiber control were compared with three techniques. First, red light delivery from the microneedles was evaluated by imaging the reflectance of the light from a white paper. Second, spatial temperature distribution of the paper in response to near‐IR light (1,064 nm, 1 W CW) was recorded using infrared thermography. Third, ex vivo adipose tissue response during 1,064 nm, (5 W CW) irradiation was recorded with bright field microscopy.

Results

Acid etching exposed a 3 mm length of the fiber core, allowing circumferential delivery of light along this length. Increasing etching time decreased microneedle diameter, resulting in increased uniformity of red and 1,064 nm light delivery along the microneedle axis. For equivalent total energy delivery, thinner microneedles reduced carbonization in the adipose tissue experiments.

Conclusions

We developed novel microscale optical diffusers that provided a more homogeneous light distribution from their surfaces, and compared performance to a flat‐cleaved fiber, a device currently utilized in clinical practice. These fiberoptic microneedles can potentially enhance clinical laser procedures by providing direct delivery of diffuse light to target chromophores, while minimizing undesirable photothermal damage in adjacent, non‐target tissue. Lasers Surg. Med. 43:914‐920, 2011. © 2011 Wiley Periodicals, Inc.
Character formulas for restricted simple modules of the special superalgebras
Authors: Shu Bin , Yao Yu‐Feng
Published: December 2011

Let k be an algebraically closed field of prime characteristic p > 2, and let S(n) be the special Lie superalgebra over k. The iso‐classes of simple restricted modules of these algebras are classified, and the character formulas of restricted simple modules are given.
Charged Poly(D,L‐lactide) Nanofibers: Towards Customized Surface Properties
Authors: Croisier Florence , Aqil Abdelhafid , Malherbe Cédric , Gilbert Bernard , Detrembleur Christophe , Jérôme Christine
Published: December 2011

Surface‐charged nanofibers were prepared by electrospinning technique (ESP). For this purpose, a copolymer bearing carboxylic acid functions was added to a poly(D,L‐lactide) solution just before ESP process. In a basic medium, negative charges were therefore revealed on fiber surface. By deposition of positively charged particles or polyelectrolytes, surface properties of the fibers could be tailor‐made for a specific application. This versatile method can, for example, be applied to the preparation of new biomedical scaffolds.
Viability, Adhesion and Differentiated Phenotype of Articular Chondrocytes on Degradable Polymers and Electro‐Spun Structures Thereof
Authors: Schneider Tobias , Kohl Benjamin , Sauter Tilman , Becker Tino , Kratz Karl , Schossig Michael , Hiebl Bernhard , Jung Friedrich , Lendlein Andreas , Ertel Wolfgang , Schulze‐Tanzil Gundula
Published: December 2011

Degradable polymers are essential to enable biomaterial‐based regenerative therapies, particularly, in articular cartilage defect healing, which remains a major clinical challenge. The aim of this study was to investigate the effect of two degradable polymers (as a film or scaffold) on primary articular chondrocytes vitality, adherence, differentiated phenotype and morphology. Films and electro‐spun scaffolds were prepared from degradable poly(ether)ester urethane (PDC), which was synthesized via co‐condensation of poly(p‐dioxanone)diol and poly(ε‐caprolactone)diol with an aliphatic diisocyanate and poly(p‐dioxanone) (PPDO). The thermal and mechanical properties and the surface roughness of the films and scaffolds were examined by differential scanning calorimetry, dynamic mechanical thermal analysis, tensile tests and optical profilometry. Primary porcine articular chondrocytes were seeded on the polymers and analysed for viability, ultrastructure (scanning electron microscopy) and immunolabelled for type II collagen. All films and scaffolds exhibited a low endotoxin load < 0.06 EU/ml and only moderate cytotoxic effects when tested with L929 cells. The results of the seeding experiments revealed that survival and adhesion of chondrocytes depended strongly on seeding density. Vital chondrocytes could be detected on both PPDO and PDC films and scaffolds. They produced the cartilage‐specific protein type II collagen indicating differentiated functions. However, they exhibited a mixed morphology on the films and a more flattened cell shape on the scaffolds. The cell/biomaterial interaction in the PPDO scaffolds or films was more intense compared to that in PDC topologies.

The polymer topology influences chondrocytes phenotype, whereby the scaffolds permitted a more continuous cell growth compared with the films.
Highly Flexible Poly(ethyl‐2‐cyanoacrylate) Based Materials Obtained by Incorporation of Oligo(ethylene glycol)diglycidylether
Authors: Tripodo Giuseppe , Wischke Christian , Lendlein Andreas
Published: December 2011

Poly(ethyl‐2‐cyanoacrylate) (PECA) is a polymer with potential medical or technical applications, which are limited due to its high brittleness. In this work, the capability of different ethylene or propylene glycol‐based oligomers to provide flexible poly(ethyl‐2‐cyanoacrylate) films upon blending is analyzed. The used oligoethers have been chosen with different end groups or lateral substituents and their effects the on macroscopic behavior of the obtained materials have been characterized. During its synthesis, in situ blending of PECA was performed with increasing quantities of oligo(ethylene glycol) diglycidyl ether providing homogeneously miscible materials with single Tg's. The Tg's decreased in a concentration dependent manner and showed negative deviation from predictions by the Fox equation, possibly due to specific intermolecular interactions. Remarkably, the mechanical properties could be tailored over a wide range with Young's moduli of 0.2 to 900 MPa, which so far has not been reported for cyanoacrylate‐based materials. Therefore, the concept of compatible blends should be further explored to establish flexible cyanoacrylate‐based materials for various technical or biomedical applications.
Novel band‐pass filters using complementary split ring resonators
Authors: La Dong‐sheng , Lu Ying‐hua
Published: December 2011

Band‐pass filters using complementary split ring resonator (CSRR) are proposed in this article. Two‐cascaded and three‐cascaded band‐pass filters using CSRR are designed, simulated, fabricated and measured. The resonant characteristics of the cascaded band‐pass filters show their advantages of compact size, excellent pass‐band performance and high out‐band suppression. The measured results show a good agreement with the simulated results. © 2011 Wiley Periodicals, Inc. Microwave Opt Technol Lett, 54:449–451 2012; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.26520
Experiment of substrate integrated waveguide interconnect measurement for high speed data transmission application
Authors: Li Zhaolong , Mahani Mohammad S. , Abhari Ramesh
Published: December 2011

Substrate integrated waveguide (SIW) has been used as a high speed interconnect for digital applications. The output eye diagram is an important indicator for evaluating the performance of the interconnect and the design of the driver and receiver units. This article studies the effect on eye diagrams based on improved driver and receiver design for a SIW interconnect system. © 2011 Wiley Periodicals, Inc. Microwave Opt Technol Lett, 2012
Broadband GaN‐ON‐Si power amplifier module with fully integrated low temperature cofired ceramic passives
Authors: Liu Rui , Schreurs Dominique , Raedt Walter De , Vanaverbeke Frederik , Mertens Robert
Published: December 2011

This article presents the first demonstration of a broadband GaN‐on‐Si power amplifier module integrated in a low temperature cofired ceramic (LTCC) technology.The active device of the amplifier is a low cost Si‐based AlGaN/GaN high electron mobility transistor. Both the input and the output matching circuits were implemented with fully embedded passives in an LTCC substrate. Measured results show that the prototype module can exhibit an output power of 28.9 dBm and a drain efficiency of 44% at 2.9 GHz. Drain efficiency over 40% is achieved across 2.9–3.3 GHz, together with an output return loss of better than −13 dB. The major advantage of using a system‐in‐package approach with LTCC technology is the dramatic cost reduction compared with a monolithic microwave integrated circuit and the size reduction compared with a hybrid PCB approach. © 2011 Wiley Periodicals, Inc. Microwave Opt Technol Lett, 54:369–372, 2012; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.26522
A GPS LNA RFIC with voltage‐controlled noise and input matching
Authors: Wu Jian‐Ming , Yeh Chun‐Hung
Published: December 2011

A low‐noise amplifier (LNA) design with a voltage‐controlled matching section using a transistor for optimal matching between noise figure (NF) and input impedance is proposed in this letter. A crucial goal for the design is to achieve low NF required in the global positioning systems with a good input matching. The proposed design is based on the cascade of a common‐gate and common‐source transistor. The gate voltage of a common‐gate transistor is used to control the real part of optimum source impedance (Zopt) approximates to 50 Ω for NF and input impedance matching. Because the design does not require inductors or capacitors for noise matching, it reduces NF and chip area substantially. The LNA is designed and implemented using WIN 0.15 μm PHEMT foundry process and has an area of 0.84 mm × 0.84 mm. The power consumption is 18 mW from a 2.5 V supply voltage. The measurement results of the proposed LNA RFIC are 2.4 dB NF, 12.6 dB gain; input‐referred 1 dB compression point (IP1dB) is −6 dBm, and input‐referred third‐order intercept point is 6.3 dBm. © 2011 Wiley Periodicals, Inc. Microwave Opt Technol Lett, 54:332–335, 2012; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.26524
Compact inverted triangle planar monopole antenna with a modified ground plane for ultra‐wideband operation
Authors: Jung Jinwoo , Lee Hyeonjin , Lim Yeongseog
Published: December 2011

A compact inverted triangle planar monopole antenna (10 mm × 22 mm × 1.6 mm) with a modified ground plane for ultra‐wideband operation is proposed.With an inverted triangle radiator and modified ground plane with quarter circular patches, the proposed antenna has impedance bandwidth measured at 7.51 GHz (3.1–10.61 GHz), defined by 2:1 VSWR. The group delay and phase are also measured and discussed. © 2011 Wiley Periodicals, Inc. Microwave Opt Technol Lett, 54:503–505, 2012; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.26528
Filter designs based on coupled transmission line model for double split ring resonators
Authors: Yan Lei , Tang Meng , Krozer Viktor , Zhurbenko Vitaliy , Jiang Chenhui , Johansen Tom Keinicke
Published: December 2011

This work presents a systematic way to design filters based on coupled transmission line model of the microstrip rectangular double split ring resonators (DSRRs). This model allows to estimate all resonance modes of DSRR and extract the quality factors of the structure for filter synthesis purpose. According to the filter specifications, the low‐pass prototype parameters are used to calculate the required coupling coefficients between coupled DSRRs. The corresponding coupling coefficients are realized by using asymmetric coupled multi‐conductors networks. The proposed filter synthesis approach is experimentally verified by comparing measured and simulated data using the developed models. © 2011 Wiley Periodicals, Inc. Microwave Opt Technol Lett, 54:467–471, 2012; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.26529
A compact second‐order frequency selective surface with broadband response
Authors: Zhou Hang , Qu Shao‐bo , Xu Zhuo , Lin Bao‐qin , Wang Jia‐fu , Ma Hua , Bai Peng , Peng Wei‐dong
Published: December 2011

A compact second‐order frequency selective surface (FSS) with broadband bandpass response is presented.The FSS is obtained by utilizing two arrays of patches coupled together using coupling apertures. Three‐legged load (TLL) patches and TLL complementary coupling apertures are selected and arranged in an interlaced grid to achieve a more compact structure. Such closely packed FSS has the merits of low‐profile, high selectivity, smaller periodicities, low insertion losses, stable performance for various incident angles and different polarizations. Moreover, its 3dB bandwidth reaches to 34.1% while the reflectivity in the central passband is about ‐35dB. Detailed design procedure, and measurement results of the FSS are presented and discussed in this letter. © 2011 Wiley Periodicals, Inc. Microwave Opt Technol Lett, 54:392–394, 2012; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.26532
A simplified and higher dynamic range version of the J1…J4 method for optical phase measurements
Authors: Marçal Luiz A. P. , Higuti Ricardo T. , Kitano Cláudio
Published: December 2011

A new and an improved version of the J1…J4 method for optical phase detection, named J1–J3 method, is described, which is more stable to phase drift and simpler for implementation than the original one. The sensor dynamic range is increased while maintaining the accuracy and the minimum detectable phase‐shift. The method is experimentally validated by using an electro‐optic intensity modulator. The agreement between theoretical and experimental results, based on the 1/f voltage noise, is demonstrated. © 2011 Wiley Periodicals, Inc. Microwave Opt Technol Lett, 54:387–392, 2012; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.26533
GaN HEMT based high‐efficiency current‐mode class‐D amplifier using chip‐on‐board technique
Authors: Park Jun‐Chul , Yoo Chan‐Sei , Kang Wonshil , Kim Dongsu , Yook Jong‐Gwan , Lee Woo Sung
Published: December 2011

This article presents a high efficiency current‐mode class‐D (CMCD) amplifier using a GaN high electron mobility transistor (HEMT) for class‐S system—a digitally controlled by delta‐sigma modulation. To enhance a drain efficiency of CMCD amplifier, the chip‐on‐board (COB) technique, which can reduce the external parasitic components of the packaged transistor and allow fast switching operation at high frequencies by minimizing distortion of the pulse waveform, is adopted. A LC‐resonance circuit with adequate Q values between each transistor and output matching network controls harmonic signal by using the lumped elements to extract pure fundamental frequency of the output signal. For a high efficiency push‐pull operation of CMCD amplifier, low‐loss rat‐race baluns are integrated at input and output circuits. From the measured results for a continuous wave of 3.35 GHz, the CMCD amplifier using COB technique shows a maximum output power of 35.88 dBm and a maximum power gain of about 10 dB. Also, the proposed CMCD amplifier provides a high power‐added‐efficiency (PAE) of 63.1% and a drain efficiency of 76.3% at maximum output power. The drain efficiency is still remained over 70% in the frequency range of 200 MHz. © 2011 Wiley Periodicals, Inc. Microwave Opt Technol Lett, 54:358–362, 2012; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.26536
Multiband patch antennas compatible with CMOS array detector for real‐time multi‐frequency terahertz imaging system
Authors: Park Wook‐Ki , Han Seong‐Tae
Published: December 2011

This letter reports a miniaturized, multiband patch antenna capable of detecting thee frequencies in conjunction with CMOS array detector element for real‐time multi‐frequency imaging in terahertz (THz)‐band.Multi‐frequency operation is desirable for THz CMOS camera design, which is achieved by using stubs and slot‐type split ring resonator on the patch antenna connected to the on‐chip CMOS detector. The proposed antenna is designed at three‐bands of 218, 338, and 400 GHz corresponding to the atmospheric transmission windows. And the performance of the multiband THz antenna is successfully demonstrated using the finite‐difference time‐domain method. © 2011 Wiley Periodicals, Inc. Microwave Opt Technol Lett, 2012
M‐shape surrounded with ring patch wideband monopole printed antenna
Authors: Aghda Majid Rafiee , Kamarudin M. R. , Iddi Hashim Uledi
Published: December 2011

In this article, a novel shape of a ring printed antenna is presented. Antenna is designed for wideband applications. There is an M‐shape patch inside the ring, which is optimized for wideband applications. The antenna operates between 2.05 and 6.85 GHz frequency bands. The measured bandwidth is about 107.87%. The proposed antenna has fabricated and tested. It has been fabricated on 30 × 51 mm2 FR4 board. A novel shape of ground plane has been used for increasing the bandwidth and removing some ripples in the result. The return loss results have been presented based on simulation and measurement. © 2011 Wiley Periodicals, Inc. Microwave Opt Technol Lett, 54:482–486, 2012; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.26541
A 0.6‐V high reverse‐isolation through feedback self‐cancellation for single‐stage noncascode CMOS LNA
Authors: Tran T. T. N. , Boon C. C. , Do M. A. , Yeo K. S.
Published: December 2011

In many designs, a low supply voltage is selected for efficient use of power. However, this often leads to low reverse‐isolation which is critical to the RF front–end circuits and particularly to the low‐noise amplifier (LNA). In this letter, a fully integrated differential low‐voltage CMOS LNA with high reverse‐isolation is presented. This LNA makes use of the single‐stage noncascode structure and the capacitive cross‐coupling (CCC) technique. The CCC technique has been utilized in many LNA designs. However, in all of the reported works using CCC, the CCC technique was mainly used to improve the noise figure (NF), not the reverse‐isolation. The poor reverse‐isolation problem in single‐stage noncascode structure has never been analyzed in the capacitive cross‐coupling cascaded low noise amplifier (CCCLNA). This work shows a novel analysis on the feedback self‐cancellation mechanism to improve the reverse‐isolation. Other analyses on input matching, gain and NF were also performed to show the feasibility of using CCC technique for the low‐voltage LNA as well as the advantages of the CCCLNA over the conventional common‐source and common‐gate (CG) LNA. The LNA consumes only 0.5 mW from 0.6 V supply voltage. It achieves a gain of 14 dB and a NF of 3.55 dB. © 2011 Wiley Periodicals, Inc. Microwave Opt Technol Lett, 54:374–379, 2012; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.26542
Novel miniaturized and high‐isolated MIMO antenna
Authors: Liu Ying , Jiang Wen , Gong Shuxi , Jiang Lintao
Published: December 2011

A novel miniaturized and high‐isolated multiple‐input multiple‐out (MIMO) antenna is proposed. It is very difficult to reduce the mutual coupling between the MIMO antenna elements for compact mobile handset. Three‐dimensional meander lines are used as the radiator, which miniaturizes the size of the antenna. Decoupling network is introduced to improve the isolation between the ports of the two monopoles effectively. Concavo–convex rectangle is used as its ground which improves the voltage standing wave ratio (VSWR) instead of the match circuits. The proposed antenna works at 2.4 GHz. Antenna prototype is fabricated and tested, which proves its performance. In the working band, the reflection coefficient of the proposed antenna is below −10 dB, and the isolation below −15 dB. The proposed antenna has patterns close to be omnidirectional. It can be used in various areas such as MIMO, Wi‐Fi, and Bluetooth. © 2011 Wiley Periodicals, Inc. Microwave Opt Technol Lett, 54:511–515, 2012; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.26545
Cost‐effective wavelength division multiplexing passive optical network delivering upstream/downstream data on a single wavelength using soliton pulse
Authors: Tawade Laxman , Deosarkar Shankar
Published: December 2011

We propose and demonstrate wavelength division multiplexing passive optical network system delivering downstream 2.5‐Gbps data and upstream 1‐Gbps data on a single wavelength using pulse source that is mode‐locked laser generating a single pulse of “sech” shape with specified power and width, that is, soliton pulse.The optical source for downstream data and upstream data is sech pulse generator at central office and reflective semiconductor optical amplifier at each optical network unit. We also investigate analysis of backscattered optical signal for upstream data and downstream data simultaneously. Bit error rate was measured to demonstrate the proposed scheme. © 2011 Wiley Periodicals, Inc. Microwave Opt Technol Lett, 54:508–511, 2012; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.26546
Small UWB antenna with bandstop function for wireless USB of mobile handsets
Authors: Lim Yohan , Yoon Young Joong , Jung Byungwoon
Published: December 2011

In this letter, a small and an internal ultra‐wideband (UWB) antenna for wireless USB of mobile handsets is proposed for UWB service in which bandstop function of 5.8‐GHz wireless local area network band is required.The ground is partially removed and the microstrip feed line is gradually tapered to obtain enhanced impedance bandwidth. λ/4 short slots for bandstop function are modified into L‐type to be accommodated in a small‐sized antenna. From the measured results, wide bandwidth of 3.15–4.75 and 7.2–10.2 GHz is achieved while 5.8 GHz is notched. Three different shapes of conventional mobile terminals are also considered for measurement. © 2011 Wiley Periodicals, Inc. Microwave Opt Technol Lett, 54:438–441, 2012; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.26551
On the accuracy of the vector fitting approximation of a cylinder nonreflecting boundary kernel
Authors: Bavelis K. , Mias C.
Published: December 2011

The article considers various factors that affect the accuracy of the vector fitting approximation of the kernel function that appears in a recently presented cylindrical nonreflecting boundary condition. © 2011 Wiley Periodicals, Inc. Microwave Opt Technol Lett, 54:277–282, 2012; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.26555
Comparison of a monopole and a PIFA handset antenna in the presence of the human head
Authors: Risco S. , Anguera J. , Andújar A. , Picher C. , Pajares J.
Published: December 2011

The great majority of wireless devices, such as handset phones, are used close to the human head. This fact modifies the antenna performance compared with a free space scenario. One of the critical aspects is that the human head absorbs power from the antenna radiation. In this sense, it is necessary to reduce such absorption not only to minimize the temperature inside the head, but also to increase the radiated power to free‐space. The performance associated to two types of handset antennas, a monopole and a planar inverted‐F antenna (PIFA) is evaluated regarding the presence of the human head. The most significant parameters (reflection coefficient, efficiency, and specific absorption rate) are measured for two different positions of the antenna (handset having the antenna close to the ear and the other when the handset is rotated 180°) as a function of the low frequency region (∼ 824—960 MHz) and high frequency region (∼1710–2170 MHz). Despite the monopole presented here occupies less space and covers more bands regarding free‐space conditions, the PIFA under analysis becomes more robust to the human head loading effect. © 2011 Wiley Periodicals, Inc. Microwave Opt Technol Lett 54:454–459, 2012; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.26565
Ultrawideband channel measurement and modeling for the future intra‐vehicle communications
Authors: Liu Leilei , Wang Yuanqing , Zhang Yan
Published: December 2011

In this article, an ultrawideband channel model within an intra‐vehicle environment is investigated.The electromagnetic wave propagation is simulated by full wave method in a three‐dimensional car structure. The channel measurement is conducted in frequency domain from 2 to 15 GHz in different scenarios. The calibration process is pointed out to ensure the accuracy in data analysis. The statistical analysis is presented using the channel impulse response calculated via inverse Fourier transform. The small scale features of the intra‐vehicle environment are then deduced. An interesting result shows that the delay spreads linearly decrease with the increased passenger number. The clustering channel model is developed based on Saleh–Valenzeula (S–V) model fitting into the vehicular environments with dense clusters and rays. © 2011 Wiley Periodicals, Inc. Microwave Opt Technol Lett 54:322–326, 2012; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.26568
Transmission resonant frequency and its amplitude prediction for ebg structure based on phase coherence
Authors: Ning Huansheng , Wang Jun , He Wei , Mao Lingfeng
Published: December 2011

A new method based on phase coherence is proposed for the strengthened resonant transmission frequency and its amplitude prediction. This method has a clear physical meaning and great convenience. A microstrip electromagnetic bandgap structure is used to verify the method, and both the simulated and measured results demonstrate its validity. © 2011 Wiley Periodicals, Inc. Microwave Opt Technol Lett 54:409–412, 2012; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.26570
Ultra‐wideband small square monopole antenna with dual band‐notched function
Authors: Ojaroudi M. , Ghobadi Ch. , Nourina J. , Ojaroudi N.
Published: December 2011

A dual band‐notched printed ultra‐wideband monopole antenna is presented, with a modified radiating patch.To generate single and dual band‐notched characteristics, we use two rectangular slots. By properly adjusting the dimensions of these slots two controllable notch resonances are achieved, but also the lower edge frequency of the band is decreased. The measured results show that the proposed dual band‐notched monopole antenna offers a wide bandwidth from 2.5 to 11 GHz, with two notched bands, covering all the 5.2/5.8 GHz wireless local area network, 3.5/5.5‐GHz WiMAX and 4‐GHz C bands. The designed antenna has a small size of 12 × 18 mm2. © 2011 Wiley Periodicals, Inc. Microwave Opt Technol Lett 54:372–374, 2012; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.26571
Broadside gain and bandwidth enhancement of microstrip patch antenna using a MNZ‐metasurface
Authors: Chung Kwok L. , Chaimool Sarawuth
Published: December 2011

This article presents a metasurfaced patch antenna in which the metasurface acts as a superstrate/cover placed atop a 2.45‐GHz patch antenna, at a small distance. The metasurface is a Mu‐near‐zero (MNZ) type, which gives a near‐zero index of refraction. The MNZ metasurface consists of 4 × 4 double‐closed‐loop resonators printed on a thin FR4 dielectric slab. The proposed antenna is low‐cost and low‐profile, having overall dimensions of 0.86 λ × 0.86 λ × 0.07 λ. The simulation and experimental results confirm that the metasurfaced antenna not only has simultaneous enhancements on broadside gain and bandwidth, but also improves antenna efficiency. © 2011 Wiley Periodicals, Inc. Microwave Opt Technol Lett 54:529–532, 2012; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.26574
The design and realization of high‐efficiency power amplifier with drain efficiency over 80% at 3.5 GHz
Authors: Lei Qi , You Fei , Dong Lei , He Songbai , Hu Zhebin
Published: December 2011

This article presents the full design methodology and implementation of inverse Class‐F power amplifier with a commercial high‐power GaN HEMT. For a 3.48 GHz continuous wave signal, the measurement results show state‐of‐the‐art power‐added‐efficiency (PAE) of 76.7%, drain efficiency of 81.1%, gain of 12.9 dB, and output power of 39.9 dBm. Within a bandwidth of 200 MHz, drain efficiency and output power are maintained above 60% and 38.5 dBm, respectively. With digital predistortion, it achieves −45 dBc of adjacent channel leakage ratio for a 2.5 MHz wideband signal with a peak‐to‐average power ratio of 8.9 dB, with an average PAE of 36.7%. © 2011 Wiley Periodicals, Inc. Microwave Opt Technol Lett 54:521–525, 2012; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.26577
A shared‐aperture dual‐wideband dual‐polarized stacked microstrip array
Authors: Gang Zhou Shi , Huat Chio Tan , Jian Lu
Published: December 2011

A shared‐aperture dual‐wideband dual‐polarized planar microstrip array is investigated.The operating frequencies are at L‐ and X‐bands. For both bands, stacked patches are selected as the radiating elements to meet the bandwidth requirements. A low‐profile design of a planar microstrip array with 2 × 1 L‐band elements interleaved with 16 × 8 X‐band elements has been achieved. The design is discussed in detail, and the measured results are presented. The measured bandwidth of VSWR < 2 reaches 8.1 and 13% for L‐ and X‐bands, respectively. The measured isolation between the L‐ and X‐band is below −35 dB, and the isolation between the cross‐pol ports is below −26 and −24 dB for L‐ and X‐band, respectively. © 2011 Wiley Periodicals, Inc. Microwave Opt Technol Lett 54:486–491, 2012; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.26579
Setups for harmonics generation using optical modulators
Authors: de Oliveira Glaucionor Lima , Giraudo Elvio Cesar , Ramos Rubens Viana
Published: December 2011

In this study, we discuss two setups for photonic generation of harmonics of an RF signal.In the first case, we analyze theoretically a setup composed of a fiber loop and a 2 × 1 Mach–Zehnder modulator able to produce even harmonics of an RF signal. Following, we show the experimental results of the generation of second and third harmonics of an RF signal using double amplitude modulation. © 2011 Wiley Periodicals, Inc. Microwave Opt Technol Lett 54:519–521, 2012; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.26583
Band‐notched UWB microstrip slot antenna with ENHANCED bandwidth by using a pair of C‐Shaped slots
Authors: Ojaroudi N. , Ojaroudi M. , Ebarhimian H.
Published: December 2011

In this article, a new frequency notched ultra‐wideband microstrip slot antenna with an S‐shaped slot in the radiating stub and a pair of C‐shaped slots in the ground structure is proposed and experimentally studied. To increase the bandwidth, a pair of C‐shaped slots was cut in the ground plane that improves the bandwidth especially at the higher frequency and provides a wide usable fractional bandwidth from 2.9 to 14.4 (135%). To generate single band‐notch characteristics, we use the S‐shaped slot in the square radiating stub that with this design, a frequency notched band of 5.07–5.93 GHz has been achieved. The proposed antenna displays a good omni‐directional radiation pattern even at higher frequencies. The measured results reveal that the presented single band‐notch slot antenna offers a very wide bandwidth with notched band. The designed antenna has a small size of 20 × 20 mm2. © 2011 Wiley Periodicals, Inc. Microwave Opt Technol Lett 54:515–518, 2012; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.26584
Dual‐band patch antenna using spiral‐shaped electromagnetic bandgap structures for cellular applications
Authors: Roseline A. Ameelia , Malathi K. , Shrivastav A.K.
Published: December 2011

This article presents a bandwidth improvement of a compact dual‐band slot antenna for 1.54/1.83 GHz cellular applications using a spiral‐like electromagnetic band gap (SEBG) structures. The rectangular slotted radiating element is surrounded by a SEBG. The antenna size is very compact (60 mm × 60 mm × 2.47 mm) and can be integrated easily with other radio frequency (RF) front‐end circuits. The working frequency of the patch antenna falls inside the electromagnetic band gap band gap which will lead to the suppression of the surface waves. The simulation is carried out using the finite difference time domain analysis technique. The bandwidth of SEBG antenna is 93.2% and 11.75% increased at lower and higher resonant frequency respectively than the patch. The EM simulated return loss, gain, directivity, radiation pattern, antenna efficiency, and voltage standing wave ratio (VSWR) are presented for proposed antenna array. Good agreement is achieved between the simulated and measured results. © 2011 Wiley Periodicals, Inc. Microwave Opt Technol Lett 54:477–482, 2012; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.26585
A 2.4‐GHz bandpass filter for flexible RF applications
Authors: Kim Jin‐Sup , Lee Kyu‐Bok , Lee Jae‐Young , Lee Ho‐Jun , Shin Hyunchol
Published: December 2011

A 2.4‐GHz bandpass filter is implemented on a flexible printed circuit board with a thickness of 127 μm for wearable RF applications.The bandpass filter is realized in a double‐sided structure, of which the top side provides the main filtering characteristics using two coupled resonators and the bottom side provides efficient signal feeding and coupling using mixed coupling scheme. The mixed coupling scheme combining the broadside‐ and cross‐coupling structures is advantageous to improve the insertion loss. The filter characteristics when bended by up to 90° are simulated using a three‐dimensional electromagnetic simulation tool and experimentally verified. Measurement results show that the insertion loss is less than 1 dB and the return loss is less than 26 dB across the total passband from 2.4 to 2.5 GHz. © 2011 Wiley Periodicals, Inc. Microwave Opt Technol Lett 54:384–387, 2012; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.26588
Stochastic optimal control problems under G‐expectation
Authors: Zhang Defei
Published: December 2011

Peng first introduced the notion of G‐Brownian motion and G‐expectation and established the stochastic calculus with respect to G‐Brownian motion in 2006. In this paper, we investigate the stochastic optimal control problems under G‐expectation and obtain dynamic programming principle. The value function is proved to be a viscosity solution of a fully nonlinear second‐order partial differential equation. A particular case of this equation is the well‐known Hamilton–Jacobi–Bellman–Isaacs equation. Copyright © 2011 John Wiley & Sons, Ltd.
Prions, Parkinson's disease and the search for a new generation of treatments
Authors: Greener Mark
Published: December 2011

Recent research suggests that aggregates of cytosolic proteins such as α‐synuclein may spread in a manner similar to prions in certain neurodegenerative diseases. Mark Greener explains how drugs that can reduce formation or increase clearance of these proteins may represent new treatment strategies for Parkinson's disease. Copyright © 2011 John Wiley & Sons, Ltd.
International League Against Epilepsy UK Chapter meeting
Authors: Anderson Joseph
Published: December 2011

York Racecourse played host to the International League Against Epilepsy (ILAE) UK Chapter's 2011 annual scientific meeting in November, with over 300 delegates attending from all over the UK. Dr Joseph Anderson, Specialist Registrar and Clinical Teaching Fellow from the University Hospital of Wales, Cardiff, reports on some of the main highlights of the meeting. Copyright © 2011 John Wiley & Sons, Ltd.