bluuebunny/crossref_metadata_2025 huggingface dataset:
A novel parallel‐coupled line diplexer excited using slot‐line resonators for ultra‐wideband communications
Authors: Hon Kuan  , Yang Ru‐Yuan , Weng Min‐Hang , Chen Wen‐Lang
Published: March 2009

In this letter, a novel design of microstrip diplexer used for ultra‐wideband communication has been proposed. The primary structure of the diplexer comprises two different parallel‐coupled line structures with slot‐line resonators (SLRs), which are used for generating the filtering response with high‐channel selectivity. The diplexer is designed to have the lower and higher passband with the operating frequencies at 3.2–4.8 GHz and 6.5–9.8 GHz, respectively. Experimental results also show a good agreement with the simulated results. © 2009 Wiley Periodicals, Inc. Microwave Opt Technol Lett 51: 1552–1555, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24356
A microstrip ring‐like diplexer for bluetooth and UWB application
Authors: Ye Chang‐Sin , Su Yan‐Kuin , Weng Min‐Hang , Hung Cheng‐Yuan
Published: March 2009

In this article, design of a microstrip ring‐like diplexer for Bluetooth and ultrawide band application is presented. Two ring‐like bandpass filters, operated at 2.4 and 4 GHz, are combined together to form the proposed microstrip diplexer. Several transmission zeros located at the passband edges are introduced to improve the passband selectivity. High isolation between the two passband greater than 28 dB is achieved in this study. The designed diplexer is investigated numerically and experimentally. Measured results show a good agreement with the simulated analysis. © 2009 Wiley Periodicals, Inc. Microwave Opt Technol Lett 51: 1518–1520, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24358
On the well‐posedness of integral equations associated with cavity Green's functions around resonant frequencies
Authors: Lu Mingyu , Jung Sungyong
Published: March 2009

In this article, theoretical analyses are carried out for integral equations associated with cavity Green's functions. When cavities are fully enclosed and lossless, conventional integral equations are ill‐posed at cavities' resonant frequencies. As a remedy, modified integral equations are formulated around resonances, and they are theoretically proved to be well‐posed. © 2009 Wiley Periodicals, Inc. Microwave Opt Technol Lett 51: 1476–1481, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24360
An improved full‐duplex radio‐over‐fiber system using optical carrier suppressed double sideband modulation at 60 GHz
Authors: Yang Hao , Wang Fa Qiang , Huang Xuguang , Liang Ruisheng , Wu Yiting
Published: March 2009

Based on improved optical carrier suppressed double sideband modulation with 60 GHz repetitive frequency, a full‐duplex radio‐over‐fiber transport system using a single source at central office was proposed and demonstrated. Carrier suppressed double sideband optical signal was generated by using an optical phase modulator and dense‐wavelength‐division‐multiplexing technique, as well as an additional external amplitude modulator for loading baseband downlink data to one first‐order sideband. A dense‐wavelength‐division‐multiplexer was used to separate the two first‐order sidebands; the lower sideband was used to carry 5 Gbit/s downstream data, whereas the upper sideband was sent to base station for reuse of modulating upstream data. The limitation of chromatic dispersion is greatly reduced due to that only one sideband is modulated. Therefore, the system of bidirectional transmission shows cost‐efficient configuration and good performance over 80 km delivery with less than 1.5 dB power penalty. © 2009 Wiley Periodicals, Inc. Microwave Opt Technol Lett 51: 1473–1476, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24361
Analysis of half E‐shaped patch for wideband application
Authors: Ansari J. A. , Kesh Dubey Satya , Mishra Anurag
Published: March 2009

A half E‐shaped patch antenna is analyzed using equivalent circuit model based on modal expansion cavity model. The antenna shows almost 50% reduction in size with the same performance as achieved by full E‐shaped patch. The proposed theory is verified by simulation and experimental results. © 2009 Wiley Periodicals, Inc. Microwave Opt Technol Lett 51: 1576–1580, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24367
Circularly polarized H‐shaped microstrip‐array antenna with a T‐slot for DSRC system roadside equipment
Authors: Choi By Sun‐Ho , Lee Hwa‐Choon , Kwak Kyung‐Sup
Published: March 2009

This article describes the design of a novel circularly polarized H‐shaped microstrip‐array antenna with a T‐slot for dedicated short‐range communication (DSRC) system roadside equipment (RSE: 5.850–5.925 GHz). The antenna system needs a correct radiation pattern, at the assigned communication area, without interference from the other radio wave propagation. The proposed antenna is designed to reduce the side lobe level (SLL) by using the proper distance for patch array and multilayer substrates for DSRC RSE. H‐shaped patches are used for circular polarization (RHCP or LHCP) with a T‐slot. The measured bandwidth of the fabricated antenna is from 5.830 to 5.939 GHz when the return loss < −10 dB. The measured axial ratio (RHCP) is 1.25–2.02 dB and gain is 15.62–15.94 dBi. The experimental 3‐dB beam width (HPBW) in the E‐plane and H‐plane are 22.52° and 24.11° at 5.91 GHz, respectively. © 2009 Wiley Periodicals, Inc. Microwave Opt Technol Lett 51: 1545–1548, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24369
An integrated CMOS low‐power UWB transmitter
Authors: Yuan Tao , Lim Gui‐Duo , Zheng Yuanjin , Li Le‐Wei , Leong Mook‐Seng
Published: March 2009

In this article, a fully integrated monocycle pulse‐based ultrawideband (UWB) transmitter is presented. Fabricated in a 0.18‐μm CMOS process, a low‐power all‐digital UWB pulse generator and modulator is proposed. The modulated pulse is further shaped by a driver amplifier. The transmitted pulses are binary phase modulated and meet the FCC UWB low frequency band (3.1–4.5 GHz) spectral mask specification. © 2009 Wiley Periodicals, Inc. Microwave Opt Technol Lett 51: 1431–1436, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24376
Ultra‐wideband slot antenna with band‐notch characteristics for wireless USB dongle applications
Authors: Krishna Deepti Das , Gopikrishna M. , Aanandan C. K. , Mohanan P. , Vasudevan K.
Published: March 2009

A compact ultra‐wideband (UWB) printed slot antenna is described, suitable for integration with the printed circuit board (PCB) of a wireless, universal, serial‐bus dongle. The design comprises of a near‐rectangular slot fed by a coplanar waveguide (CPW) printed on a PCB of size 20 × 30 mm2. It has a large bandwidth covering the 3.1–10.6 GHz UWB band, with omnidirectional radiation patterns. Further, a notched band centered at 5.45 GHz wireless local area network bands is obtained within the wide bandwidth by inserting a narrow slot inside the tuning stub. Details of the antenna design are described, and the experimental results of the constructed prototype are presented. The time domain studies on the antenna shows a linear phase response throughout the band except at the notched frequency. The transient analysis of the antenna indicates very little pulse distortion confirming its suitability for high speed wireless connectivity. © 2009 Wiley Periodicals, Inc. Microwave Opt Technol Lett 51: 1500–1504, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24385
A modified generalized Chebyshev low‐pass filter with wide stopband
Authors: Kim Inseon , Kim Kwisoo , Lim Jongsik , Ahn Dal
Published: March 2009

We developed a modified generalized Chebyshev (MGC) rational function and synthesized a low‐pass filter (LPF) to implement it. The conventional generalized Chebyshev (GC) filter and proposed MGC filter have an equal ripple in passband. However, in stopband, the GC filter has only one transmission zero (or attenuation pole) at a finite frequency (f0), whereas the MGC filter has transmission zeros at two finite frequencies (f01and f02). The second transmission zero at f02can suppress harmonics (or spurious responses). We designed and fabricated a low‐pass filter according to the proposed theory. The stopband of the MGC filter was 4.7 times wider than that of the GC filter. © 2009 Wiley Periodicals, Inc. Microwave Opt Technol Lett 51: 1428–1431, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24389
Compact LTCC band pass filter using high‐Q bondwire inductor for RF system‐in‐package applications
Authors: Jang Jae‐Won , Byun Jindo , Lee Hai‐Young
Published: March 2009

A low‐temperature cofired ceramics(LTCC)‐embedded bandpass filter (BPF) using a high quality (Q) factor (130) bondwire inductor is proposed for radio frequency (RF) system‐in‐package (SiP) applications. The usage of high‐Q bondwire inductors significantly improves the passband insertion loss (1.35 dB) compared with that (2.0 dB) of embedded spiral inductors at 5.25 GHz and also greatly reduces the device size to 1.000 × 1.500 × 0.675 mm3. The insertion loss and the size of the proposed bondwire filter are the best compared with those of open literature filters. Excellent tolerances of 1.9% and 4.4% are, respectively, measured for the cutoff frequency and the insertion loss. We expect the proposed bondwire filter play an important role to improve the performance and to reduce the sizes of RF SiP circuits. © 2009 Wiley Periodicals, Inc. Microwave Opt Technol Lett 51: 1424–1428, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24390
A compact microstrip dual‐wideband bandpass filter using ladder stub resonator
Authors: Weng Min‐Hang , Liauh Chihng‐Tsung , Wu Hung‐Wei , Vargas Steve Ramírez , Yang Ru‐Yuan
Published: March 2009

In this article, we present a novel compact dual wideband bandpass filter (BPF) by using a new structure of ladder stub resonator (LSR). The proposed LSR can produce attenuation poles to form low loss and dual‐wideband bandpass response. By tuning the structure parameters of LSR, the dual‐band characteristic can be controlled. The measured 3 dB fractional bandwidth (FBW) at first and second passbands are 41.5% and 25.7%, respectively. The experiment results of the fabricated filter agree well with the electromagnetic (EM) simulation. © 2009 Wiley Periodicals, Inc. Microwave Opt Technol Lett 51: 1391–1393, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24392
Design of meander square‐ring resonator and its application in RF power divider
Authors: Zhang Fei
Published: March 2009

First, this letter presents a novel meander square‐ring resonator (MSRR) and its stop‐band and slow‐wave effects are investigated. Served by the proposed MSRR, unwanted higher‐order 2nd and 3rd harmonics of power divider are effectively rejected benefiting from its stop‐band effect without any additional filter, and the physical length of quarter‐wavelength 70.7 ohm microstrip in power divider is halved utilizing its slow‐wave effect without decreasing the electrical length. Finally, power divider with area reduction by 42.6% is successfully obtained, compared with conventional design. © 2009 Wiley Periodicals, Inc. Microwave Opt Technol Lett 51: 1602–1604, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24394
Traumatic brain injury in the United States: an epidemiologic overview
Authors: Summers Carl R. , Ivins Brian , Schwab Karen A.
Published: March 2009

A basic description of severity and frequency is needed for planning healthcare delivery for any disease process. In the case of traumatic brain injury, severity is typically categorized into mild, moderate, and severe with information from a combination of clinical observation and self‐report methodologies. Recent US civilian epidemiological findings measuring the frequency of mortality and morbidity of traumatic brain injury are presented, including demographic and etiological breakdowns of the data. Falls, motor vehicle accidents, and being struck by objects are the major etiologies of traumatic brain injury. US civilian and Army hospitalization trends are discussed and compared. Features of traumatic brain injuries from Operation Iraqi Freedom and Operation Enduring Freedom are discussed. Mt Sinai J Med 76:105–110, 2009. © 2009 Mount Sinai School of Medicine
Mild traumatic brain injury
Authors: Bruns John J. , Jagoda Andy S.
Published: March 2009

Mild traumatic brain injury accounts for 1% to 2% of emergency department visits in the United States. Up to 15% of these patients will have an acute intracranial lesion identified on head computed tomography; less than 1% of mild traumatic brain injuries will require neurosurgical intervention. Clinical research over the past decade has focused on identifying the subgroup of patients with mild traumatic brain injury with acute traumatic lesions on computed tomography and specifically those at risk for harboring a potentially catastrophic lesion. This research has been used to generate evidence‐based guidelines to assist in clinical decision making. There is no evidence to support the use of plain film radiographs in the evaluation of patients with mild traumatic brain injury. The utility of brain‐specific biomarkers is rapidly evolving, and a growing body of evidence supports their potential role in determining the need for neuroimaging. Clinical predictors for identifying patients with abnormal computed tomography have been established and, if used, may have a significant positive impact on traumatic brain injury–related morbidity and healthcare utilization in the United States. Patients with negative computed tomography are at almost no risk of deteriorating; however, they should be counseled regarding postconcussive symptoms and should be given appropriate written instructions and referrals at discharge. Mt Sinai J Med 76:129–137, 2009. © 2009 Mount Sinai School of Medicine
Vibratory thresholds and mobility in older persons
Authors: Buchman Aron S. , Wilson Robert S. , Leurgans Sue , Bennett David A.
Published: March 2009

We tested the hypothesis that vibratory thresholds in the elderly are related to mobility. In all, 629 older persons without dementia underwent testing including 11 lower extremity performance measures and modified United Parkinson's Disease Rating Scale (UPDRS), summarized as composite mobility and global parkinsonian signs. Vibratory thresholds were measured at the ankle and toes bilaterally using the graduated Rydel–Seiffer tuning fork. In linear regression models adjusted for age, sex, and education, vibratory threshold was associated with composite mobility (estimate, 0.047, SE = 0.011, P < 0.001) and global parkinsonian signs score (estimate, −0.252, SE = 0.126, P = 0.047). These findings were primarily due to the association of vibratory threshold with gait and balance components of composite mobility and parkinsonian gait. These results were unchanged when we controlled for body mass index, physical activity, cognition, depression, vascular risk factors, vascular disease burden, joint pain, and falls. Vibratory thresholds are associated with mobility, supporting the link between peripheral sensory nerve function and mobility in the elderly. Muscle Nerve, 2009
Capacitated lot‐sizing and scheduling with parallel machines, back‐orders, and setup carry‐over
Authors: Quadt Daniel , Kuhn Heinrich
Published: March 2009

We address the capacitated lot‐sizing and scheduling problem with setup times, setup carry‐over, back‐orders, and parallel machines as it appears in a semiconductor assembly facility. The problem can be formulated as an extension of the capacitated lot‐sizing problem with linked lot‐sizes (CLSPL). We present a mixed integer (MIP) formulation of the problem and a new solution procedure. The solution procedure is based on a novel “aggregate model,” which uses integer instead of binary variables. The model is embedded in a period‐by‐period heuristic and is solved to optimality or near‐optimality in each iteration using standard procedures (CPLEX). A subsequent scheduling routine loads and sequences the products on the parallel machines. Six variants of the heuristic are presented and tested in an extensive computational study. © 2009 Wiley Periodicals, Inc. Naval Research Logistics 2009
Diffusion‐weighted MRI measurements on stroke patients reveal water‐exchange mechanisms in sub‐acute ischaemic lesions
Authors: Lätt J. , Nilsson M. , van Westen D. , Wirestam R. , Ståhlberg F. , Brockstedt S.
Published: March 2009

The aim of this study was to investigate the diffusion time dependence of signal‐versus‐b curves obtained from diffusion‐weighted magnetic resonance imaging (DW‐MRI) of sub‐acute ischaemic lesions in stroke patients. In this case series study, 16 patients with sub‐acute ischaemic stroke were examined with DW‐MRI using two different diffusion times (60 and 260 ms). Nine of these patients showed sufficiently large lesions without artefacts to merit further analysis. The signal‐versus‐b curves from the lesions were plotted and analysed using a two‐compartment model including compartmental exchange. To validate the model and to aid the interpretation of the estimated model parameters, Monte Carlo simulations were performed. In eight cases, the plotted signal‐versus‐b curves, obtained from the lesions, showed a signal–curve split‐up when data for the two diffusion times were compared, revealing effects of compartmental water exchange. For one of the patients, parametric maps were generated based on the extracted model parameters. These novel observations suggest that water exchange between different water pools is measurable and thus potentially useful for clinical assessment. The information can improve the understanding of the relationship between the DW‐MRI signal intensity and the microstructural properties of the lesions. Copyright © 2009 John Wiley & Sons, Ltd.
Algorithms by design: A new normalized time‐weighted residual methodology and design of a family of energy–momentum conserving algorithms for non‐linear structural dynamics
Authors: Masuri S. U. , Hoitink A. , Zhou X. , Tamma K. K.
Published: March 2009

A new approach termed as the hybrid displacement–strain‐based normalized time‐weighted residual approach is presented to accurately model non‐linear structural dynamic problems. The focus here is restricted to all possible algorithmic designs within the class of linear multi‐step methods that fall under the umbrella of the generalized single solve single step linear dynamic framework originally developed via the classical time‐weighted residual approach involving a single solve within each time step as such designs are the most predominant in research and commercial software (Int. J. Numer. Meth. Engng 2004; 59:597–668; Int. J. Numer. Meth. Engng 2006; 66:1738–1790). However, traditional practices via classical time‐weighted residual approaches fail to preserve the underlying physics and stability and do not serve the purposes of extensions to non‐linear dynamic situations. In contrast, a new normalized time‐weighted residual approach is proposed that naturally enables such extensions leading to the design of a family of conserving time operators for unconstrained conservative dynamic systems without resorting to enforcing energy constraints as in past practices. Consequently, the algorithmic stability (in the sense of energy stability) via this approach for non‐linear dynamic problems is also preserved. For linear dynamic situations, it reverts to the classical paradigm. Only simple numerical illustrations are purposely presented to demonstrate the basic concepts. Copyright © 2009 John Wiley & Sons, Ltd.
PTEN genomic deletion is associated with p‐Akt and AR signalling in poorer outcome, hormone refractory prostate cancer
Authors: Sircar Kanishka , Yoshimoto Maisa , Monzon Federico A , Koumakpayi Ismael H , Katz Ruth L , Khanna Abha , Alvarez Karla , Chen Guanyong , Darnel Andrew D , Aprikian Armen G , Saad Fred , Bismar Tarek A , Squire Jeremy A
Published: March 2009

PTEN haploinsufficiency is common in hormone‐sensitive prostate cancer, though the incidence of genomic deletion and its downstream effects have not been elucidated in clinical samples of hormone refractory prostate cancer (HRPC). Progression to androgen independence is pivotal in prostate cancer and mediated largely by the androgen receptor (AR). Since this process is distinct from metastatic progression, we examined alterations of the PTEN gene in locally advanced recurrent, non‐metastatic human HRPC tissues. Retrospective analyses of PTEN deletion status were correlated with activated downstream phospho‐Akt (p‐Akt) pathway proteins and with the androgen receptor. The prevalence of PTEN genomic deletions in transurethral resection samples of 59 HRPC patients with known clinical outcome was assessed by four‐colour FISH analyses. FISH was performed using six BAC clones spanning both flanking PTEN genomic regions and the PTEN gene locus, and a chromosome 10 centromeric probe. PTEN copy number was also evaluated in a subset of cases using single nucleotide polymorphism (SNP) arrays. In addition, the samples were immunostained with antibodies against p‐Akt, p‐mTOR, p‐70S6, and AR. The PTEN gene was deleted in 77% of cases, with 25% showing homozygous deletions, 18% homozygous and hemizygous deletions, and 34% hemizygous deletions only. In a subset of the study group, SNP array analysis confirmed the FISH findings. PTEN genomic deletion was significantly correlated to the expression of downstream p‐Akt (p < 0.0001), AR (p = 0.025), and to cancer‐specific mortality (p = 0.039). PTEN deletion is common in HRPC, with bi‐allelic loss correlating to disease‐specific mortality and associated with Akt and AR deregulation. Copyright © 2009 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.
Structure and mechanical properties of impact modified poly(butylene terephthalate)/poly(ethylene terephthalate) blends
Authors: Guerrica‐Echevarría G. , Eguiazábal J.I.
Published: March 2009

Two poly(butylene terephthalate) (PBT)‐rich compositions of PBT/poly(ethylene terephthalate) (PET) blends (5/1 and 2/1) were mixed with up to 30 wt% of a maleinized poly(ethylene‐octene) copolymer (mPEO). The blends were composed of a PBT/PET amorphous phase, a pure mPEO amorphous phase, and the crystalline phases of PBT and mPEO. The average size of the dispersed mPEO particles was larger in the (PBT/PET 5/1)/mPEO blends than in the (PBT/PET 2/1)/mPEO blends, but in both cases larger than that of PET/mPEO blends and smaller than that of PBT/mPEO blends from previous works. The Young's modulus and the yield stress decreased with increasing mPEO contents and the ductility of the 2/1‐based blends remained constant at higher mPEO contents compared to the 5/1‐based blends. Super‐toughness was obtained in both blends, but only the critical interparticle distance (IDc) of the (PBT/PET 5/1)/mPEO blends was used for comparison with those of PET/mPEO, poly(trimethylene terephthalate) (PTT)/mPEO and PBT/mPEO blends in terms of adhesion, because the (PBT/PET 2/1)/mPEO blends showed a simultaneous change in matrix modulus and adhesion. This comparison provided additional support to the proposed “saturation” of the interactions between the ester and maleic groups in this series and to the role of adhesion on IDc (higher adhesion, lower IDc). POLYM. ENG. SCI., 2009. © 2009 Society of Plastics Engineers
Facile fabrication of novel Eu‐containing copolymer and luminescent properties
Authors: Huang Ziqun , Zhang Huaihong , Guo Jiaxiu , Wang Jianli , Chen Yaoqiang
Published: March 2009

A new Eu‐containing copolymer was successfully fabricated through two steps. First, the Eu‐containing monomer was synthesized from 4‐Vinylbenzoic acid and europium ion (Eu3+) complex, which rare‐earth ions connect with the ligand by covalent bands. Next, the copolymer was obtained by free‐radical copolymerization of Eu‐containing monomer with methyl methacrylate using 2, 2′‐azobis(isobutyronitrile) (AIBN) as initiator at low temperature. Infrared spectroscopy, gel permeation chromatography and scanning electron microscopy were applied to characterize the structure of the polymer. UV‐visible absorption/photoluminescence spectra and fluorescence spectra were taken to valuate the photophysical properties of the obtained Eu‐containing copolymer. The experimental result shows that the strong luminescence of europium ions substantiates optimum energy match and effective intramolecular energy transfer between the triplet state energy of coordination complex and the emissive energy level of the rare‐earth ions. A study of the dependence of emission intensities of the Eu‐containing nanoparticles on the Eu content showed that the emission intensities increased nearly linearly with increasing Eu content. In addition, no significant emission concentration quenching phenomenon was observed at the Eu content of 0–4.61 mol%. The hybrid material systems can be expected to have potential applications in light conversion materials. POLYM. ENG. SCI., 2009. © 2009 Society of Plastics Engineers
Membranes, strings and integrability
Authors: Krishnan C. , Maccaferri C.
Published: March 2009

In the first half of this note, after briefly motivating and reviewing membrane field theories, we discuss their BPS funnel solutions. We discuss some aspects of embedding M‐theory fuzzy funnels in these theories. In the second half, we focus on ABJM theory and discuss a test of AdS4/CFT3 based on integrability. We discuss a numerical mismatch at one loop in worldsheet perturbation theory and its possible resolutions.
Non chiral dynamical flavors and screening on the conifold
Authors: Bigazzi F. , Cotrone A.L. , Paredes A. , Ramallo A.
Published: March 2009

We present a new class of string theory solutions which are conjectured to be dual to the 𝒩 = 1 conifold theory by Klebanov and Witten coupled to non chiral massive dynamical flavors. These are introduced, in the Veneziano limit, by means of suitably embedded and smeared D7‐branes whose full backreaction on the background is taken into account. The string solutions are used to study chromoelectric charge screening effects due to the dynamical flavors in the non perturbative regime of the dual gauge theories.
Wrapping interactions in standard and β‐deformed 𝒩 = 4 SYM
Authors: Fiamberti F. , Santambrogio A. , Sieg C. , Zanon D.
Published: March 2009

We study finite‐size effects on the anomalous dimensions of two‐impurity operators at four loops in 𝒩 = 4 SYM and of single‐impurity operators at the critical order up to nine loops in the β‐deformed version of the theory.
𝒩 = 2 world‐sheet approach to D‐branes on generalized Kähler geometries: II. Dualities
Authors: Sevrin A. , Staessens W. , Wijns A.
Published: March 2009

Following the general formalism reviewed in [10] we present several examples of possible D3‐brane configurations on four‐dimensional generalized Kähler geometries. We will discuss T‐duality transformations in 𝒩 = 2 boundary superspace and apply the duality transformations to the constructed D3‐branes. The duality transformations lead to a systematic method to construct coisotropic branes, even on target spaces that are not hyper‐Kähler.
Laboratory and field cage studies on female‐targeted attract‐and‐kill bait stations for Anastrepha suspensa (Diptera: Tephritidae)
Authors: Heath Robert R , Lavallee Stephen G , Schnell Elena , Midgarden David G , Epsky Nancy D
Published: March 2009

BACKGROUND: Development of attract‐and‐kill bait stations for pest fruit flies has been limited by the water solubility of sugar needed as a feeding stimulant and by the volatility of chemical attractants. A wax‐based matrix was developed that provides the longevity needed for field use and is biodegradable.

RESULTS: Laboratory bioassays with the Caribbean fruit fly, Anastrepha suspensa (Loew), confirmed the efficacy of bait stations containing avermectin, methomyl, spinosad and phloxine B. Field cage studies demonstrated that significant mortality occurred with either 1% (w/v) spinosad or 1% (w/v) methomyl bait stations versus pesticide‐free bait stations. Bait stations were exposed to environmental conditions by placing them in trees at the ARS station in Miami, Florida, between tests. There was no loss in efficacy, in spite of exposure to over 360 mm of rainfall over the 56 days of the study, indicating that the bait stations could provide population suppression for at least 1–2 months when used in subtropical environments.

CONCLUSION: A long‐lasting, female‐targeted fruit fly bait station, such as the one developed herein, could provide a cost‐effective option for fruit fly population suppression that would be an important tool in tephritid pest management and control. Additional studies are needed to demonstrate efficacy against wild fruit fly populations and determine deployment strategies. Copyright © 2009 Society of Chemical Industry
IR and EPR study of ammonia adsorption effect on silicon nanocrystals
Authors: Konstantinova Elizaveta , Pavlikov Alexander , Vorontsov Alexander , Efimova Alexandra , Timoshenko Victor , Kashkarov Pavel
Published: March 2009

IR and EPR spectroscopy is used to investigate the effect of adsorption of dry and wet ammonia on the concentration of equilibrium charge carriers in porous silicon layers with various initial types of dopants. It is found by means of IR spectroscopy that only in the presence of water molecules the ammonia adsorption results in an increase in the concentration of free charge carriers in n‐type samples up to a level exceeding 1018 cm–3. In p‐type samples, a nonmonotonic dependence of the charge‐carrier concentration on ammonia pressure is observed. By means of EPR spectroscopy in the atmosphere of wet ammonia the generation of conduction‐band electrons in p‐type silicon nanocrystals and the increase in the electron concentration in n‐type silicon nanocrystals in comparison with the initial level are observed. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Highly ordered hexagonally arranged sub‐200 nm diameter vertical cylindrical pores on p‐type Si using non‐lithographic pre‐patterning of the Si substrate
Authors: Zacharatos Filimon , Gianneta Violetta , Nassiopoulou Androula G.
Published: March 2009

Anodically etched two‐dimensional (2‐D) arrays of highly ordered sub‐200 nm in diameter vertical cylindrical pores were fabricated on p‐type Si wafers, with a resistivity of 6–8 Ω cm, by non‐lithographic pre‐patterning of the silicon substrate through a self‐assembled porous anodic alumina (PAA) thin film, directly grown on the Si wafer. The PAA film was grown by electrochemical oxidation of a thin Al film in an oxalic acid aqueous solution electrolyte. Through the PAA pores, concave etch pits were formed on Si by chemical etching, that were then used as pore initiation sites for electrochemical macroporous silicon formation. The so formed vertical cylindrical pore arrays showed perfect hexagonal arrangement on the Si surface. A pore diameter down to 180 nm and a pore height up to ∼1 μm were achieved for the first time on p‐type Si. The developed technology is particularly interesting for photonic crystals and sensors applications. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Incorporation and characterization of boron neutron capture therapy agents into mesoporous silicon and silicon nanowires
Authors: Jiang Ke , Loni Armando , Canham Leigh T. , Coffer Jeffery L.
Published: March 2009

The tunable pore size, biodegradability, and surface chemistry of mesoporous silicon (BioSiliconTM) are important to a broad spectrum of uses for drug delivery. For the case of Boron Neutron Capture Therapy (BNCT), encapsulation of a given boron‐containing drug molecule within a porous BioSiliconTM microparticle provides a vehicle for a brachytherapy method that avoids the necessity of drug modification. In this work, the loading and characterization of three clinically approved BNCT drugs into mesoporous Si is demonstrated. Because of difficulties associated with light element detection, a method based on a Beer's Law analysis of selected FTIR vibrational bands has been developed to estimate boron‐containing drug loading in these materials. As a complementary nanostructural platform, a cathodic deposition process for the surface enriched growth of selected drugs onto the surface of silicon nanowires is also described. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Domain‐wall propagation in thin Fe‐rich glass‐coated amorphous wires
Authors: Zhukova V. , Blanco J. M. , Ipatov M. , Gonzalez J. , Zhukov A.
Published: March 2009

Using the Sixtus–Tonks method we experimentally studied the velocity of domain‐wall (DW) propagation, v, of Fe69Si10B15C6 with different metallic nucleus diameter, d, and different total diameter, D (d = 14 μm; D = 33 μm and d = 18 μm; D = 23.4 μm, respectively) in the temperature range between 78 K and 300 K and at different frequencies of applied magnetic field. We found experimentally that the v (H) dependence is essentially nonlinear, showing at least two different regions with significantly higher DW mobility, S = dv/ dH, at the low‐field limit. A significant temperature dependence of DW mobility, S, is found. The magnetic field v (H) dependence, as well as the S (H) dependence and Hcr are sensitive to the sample geometry. The origin of such dependences on internal stresses is attributed to the magnetoelastic energy contribution related with strong internal stresses as well as with interaction of moving DW with defects. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
A new method for the comparison of survival distributions
Authors: Lin Xun , Xu Qiang
Published: March 2009

The assessment of overall homogeneity of time‐to‐event curves is a key element in survival analysis in biomedical research. The currently commonly used testing methods, e.g. log‐rank test, Wilcoxon test, and Kolmogorov–Smirnov test, may have a significant loss of statistical testing power under certain circumstances. In this paper we propose a new testing method that is robust for the comparison of the overall homogeneity of survival curves based on the absolute difference of the area under the survival curves using normal approximation by Greenwood's formula. Monte Carlo simulations are conducted to investigate the performance of the new testing method compared against the log‐rank, Wilcoxon, and Kolmogorov–Smirnov tests under a variety of circumstances. The proposed new method has robust performance with greater power to detect the overall differences than the log‐rank, Wilcoxon, and Kolmogorov–Smirnov tests in many scenarios in the simulations. Furthermore, the applicability of the new testing approach is illustrated in a real data example from a kidney dialysis trial. Copyright © 2009 John Wiley & Sons, Ltd.
Magnetizability of doublet radicals using Fock space multi‐reference coupled cluster method
Authors: Ravichandran Lalitha , Vaval Nayana , Pal Sourav
Published: March 2009

In this article, we report the first implementation of the recently developed Fock space multireference coupled cluster (FSMRCC) response approach for magnetizabilities. The FSMRCC treats dynamic and static correlation in a very extensive manner. We report pilot application of the diamagnetizability of NO, NO2, OH, and BH2 radicals. We also report preliminary applications of the paramagnetic magnetizability of the NO radical. Standard atom‐centered Gaussian basis functions have been used, and this allowed us to study the gauge dependence of the magnetizabilities. © 2009 Wiley Periodicals, Inc. Int J Quantum Chem, 2009
Efficient encoding and rapid decoding for interactive visualization of large three‐dimensional hyperspectral chemical images
Authors: Reichenbach Stephen E. , Henderson Alex , Lindquist Robert , Tao Qingping
Published: March 2009

Interactive visualization of data from a new generation of chemical imaging systems requires coding that is efficient and accessible. New technologies for secondary ion mass spectrometry (SIMS) generate large three‐dimensional, hyperspectral datasets with high spatial and spectral resolution. Interactive visualization is important for chemical analysis, but the raw dataset size exceeds the memory capacities of typical current computer systems and is a significant obstacle. This paper reports the development of a lossless coding method that is memory efficient, enabling large SIMS datasets to be held in fast memory, and supports quick access for interactive visualization. The approach provides pixel indexing, as required for chemical imaging applications, and is based on the statistical characteristics of the data. The method uses differential time‐of‐flight to effect mass‐spectral run‐length‐encoding and uses a scheme for variable‐length, byte‐unit representations for both mass‐spectral time‐of‐flight and intensity values. Experiments demonstrate high compression rates and fast access. Copyright © 2009 John Wiley & Sons, Ltd.
Matrix/analyte ratio influencing polymer molecular weight distribution in matrix‐assisted laser desorption/ionization time‐of‐flight mass spectrometry
Authors: Schlosser Gitta , Jakab Annamária , Pocsfalvi Gabriella , Vékey Károly , Hudecz Ferenc , Mező Gábor
Published: March 2009

Matrix‐assisted laser desorption/ionization time‐of‐flight mass spectrometry (MALDI‐TOF‐MS) has been used to characterize poly(L‐lysine) polymers and unique oligomer peptides, like 10‐, 15‐ and 25‐mer [Lys]n oligolysine peptides. Several matrices have been tried in order to find optimal conditions, but only α‐cyano‐4‐hydroxycinnamic acid gave analytically useful spectra. The synthetic oligomers and their mixtures gave good quality spectra, showing protonated and cationized molecules, including doubly charged species. The polymers, analogously, gave a wide distribution of single‐ and double‐cationized peak series. The polymer distributions observed indicate the presence of significant suppression effects. The concentration (matrix/analyte ratio) was found to influence the results significantly; distributions shifting to higher masses when higher polymer concentrations were used. This effect was studied in detail using the synthetic (‘monodisperse’) oligolysine peptides. It was found that the relative intensities change by over an order of magnitude in the 0.1–10 pmol/µL concentration range (typical for most proteomic analyses). The results indicate that concentration effects need to be considered when MALDI‐MS is used for quantitative purposes. Copyright © 2009 John Wiley & Sons, Ltd.
Study of the oxidation dynamics of ethyl cysteinate dimer in solution by ultra‐performance liquid chromatography with tandem mass spectrometry
Authors: Qiao Jin‐Ping , Sun Xiao‐Tao , Zhu Lin
Published: March 2009

Diaminodithiol (N2S2)‐type compounds readily oxidize to produce disulfides. We found that some ligands failed to produce a prospective protonated molecular ion peak but gave a peak of [M–2+H]+, whereas others produced both [M+H]+ and [M–2+H]+ peaks in electrospray ionization mass spectra. In this study, an important N2S2 ligand, the ethyl cysteinate dimer (ECD), was investigated with high‐resolution accurate mass measurements and tandem mass spectrometric analysis. The elemental compositions of ECD and its oxidized product were analyzed. The oxidation of ECD was confirmed. An ultra‐performance liquid chromatography/tandem mass spectrometry (UPLC/MS/MS) method in multiple reaction monitoring mode was developed, and ECD and its oxidized product were quantitated in solution. The dynamic oxidation process of ECD in solution was studied in detail. The full time course of the decrease in ECD and the increase in its oxide was observed; the oxidation procedure followed first‐order kinetics, and the half‐life time of ECD was 51 min. Copyright © 2009 John Wiley & Sons, Ltd.
In situ soil stabilization for source control of a lithium and bromate groundwater plume
Authors: Schaar Ralph G.
Published: March 2009

Historic mineral ore processing operations at the former Cyprus Foote Mineral Site located in East Whiteland Township, Pennsylvania, have resulted in the creation of an approximately 10,000‐foot‐long off‐site groundwater plume impacted with lithium and bromate. The plume emanating from the site is impacting the groundwater quality of downgradient private residences. As an early part of the remedial implementation, the private residences were provided with public water connections while the source control efforts were being designed and implemented.

Bromate and lithium have recently emerged as groundwater contaminants subjected to increased regulatory scrutiny. This is evidenced in a recently lowered Federal Maximum Contaminant Level (MCL) for bromate of 0.010 milligrams per liter and a Medium‐Specific Concentration (MSC) of 0.005 mg/L for lithium recently proposed by the Pennsylvania Department of Environmental Protection (PADEP) for all groundwater within the Commonwealth.

Elevated concentrations for bromate and lithium were detected above the Proposed Remediation Goals (PRGs) for the site, MCLs, and MSCs at a distance of 7,300 feet and 9,200 feet from the source area, respectively.

To reduce the contaminant concentrations within the groundwater plume, which will ultimately result in a regressing plume, and to enable the Brownfield redevelopment of this Superfund site, auger‐based, in situ soil stabilization (ISS) with depths of up to 75 feet below ground surface (bgs) was selected as the remedy.

The remedial implementation required the temporary removal and relocation of over 100,000 cubic yards of overburden to expose the lithium‐bearing tailings prior to treatment. Using customized 90‐foot‐long, 9‐foot‐diameter augers attached to cranes and drilling platforms, ancillary support excavators, and approximately 21,000 tons of reagent; 2,019 ISS columns were advanced to depths ranging from 10 to 74 feet bgs. This resulted in the creation of an in situ low‐permeablity 117,045‐yd3 “quasi‐monolith,” which encompasses a lateral extent of approximately three acres.

The integration of a comprehensive ISS design with a comprehensive long‐term groundwater‐monitoring plan ensured the success of the ISS implementation and will enable a continued evaluation of the off‐site groundwater quality. © 2009 Wiley Periodicals, Inc.
A Methodological Approach to Tracing Cell Lineage in Human Epithelial Tissues
Authors: Fellous Tariq G. , McDonald Stuart A.C. , Burkert Julia , Humphries Adam , Islam Shahriar , De-Alwis Nemantha M.W. , Gutierrez-Gonzalez Lydia , Tadrous Paul J. , Elia George , Kocher Hemant M. , Bhattacharya Satyajit , Mears Lisa , El-Bahrawy Mona , Turnbull Douglas M. , Taylor Robert W. , Greaves Laura C. , Chinnery Patrick F. , Day Christopher P. , Wright Nicholas A. , Alison Malcolm R.
Published: March 2009

Methods for lineage tracing of stem cell progeny in human tissues are currently not available. We describe a technique for detecting the expansion of a single cell's progeny that contain clonal mitochondrial DNA (mtDNA) mutations affecting the expression of mtDNA-encoded cytochrome c oxidase (COX). Because such mutations take up to 40 years to become phenotypically apparent, we believe these clonal patches originate in stem cells. Dual-color enzyme histochemistry was used to identify COX-deficient cells, and mutations were confirmed by microdissection of single cells with polymerase chain reaction sequencing of the entire mtDNA genome. These techniques have been applied to human intestine, liver, pancreas, and skin. Our results suggest that the stem cell niche is located at the base of colonic crypts and above the Paneth cell region in the small intestine, in accord with dynamic cell kinetic studies in animals. In the pancreas, exocrine tissue progenitors appeared to be located in or close to interlobular ducts, and, in the liver, we propose that stem cells are located in the periportal region. In the skin, the origin of a basal cell carcinoma appeared to be from the outer root sheath of the hair follicle. We propose that this is a general method for detecting clonal cell populations from which the location of the niche can be inferred, also affording the generation of cell fate maps, all in human tissues. In addition, the technique allows analysis of the origin of human tumors from specific tissue sites.

Disclosure of potential conflicts of interest is found at the end of this article.
Natural pedagogical conversations in high school students' internship
Authors: Hsu Pei‐Ling , Roth Wolff‐Michael , Mazumder Asit
Published: March 2009

Many science educators encourage student experiences of “authentic” science by means of student participation in science‐related workplaces. Little research has been done, however, to investigate how “teaching” naturally occurs in such settings, where scientists or technicians normally do not have pedagogical training and generally do not have time (or value) receiving such training. This study examines how laboratory members without a pedagogical background or experience in teaching engage high school students during their internship activities. Drawing on conversation analysis, we analyze the minute‐by‐minute transactions that occurred while high school students participated in a leading environmental science laboratory. We find that the participation trajectory was based on demonstration‐practice‐connect (D‐P‐C) phases that continually recurred in the process of “doing” science. Concerning the transactional structures, we identify two basic conversation patterns—Initiate‐Clarify‐Reply (I‐C‐R) and Initiate‐Reply‐Clarify‐Reply (I‐R‐C‐R)—that do not only differ from the well‐known Initiate‐Reply‐Evaluate (I‐R‐E) patterns previously observed in science classrooms, but also could be combined to constitute more complex patterns. With respect to the organization of natural pedagogical conversations, we find that there were not only of preferred and dispreferred modes of responding but also ambiguous dispreferred modes; and the formulating organization not only includes self‐formulating but also other‐formulating. These natural pedagogical conversations helped, on the one hand, students to clarify their understanding and, on the other hand, technicians (or teachers) to teach toward different needs for different students in different contexts. © 2009 Wiley Periodicals, Inc. J Res Sci Teach 46: 481–505, 2009