bluuebunny/crossref_metadata_2025 huggingface dataset:
Computer‐aided design of broadband single balanced waveguide mixer at K‐band
Authors: Kumar Arun
Published: January 2011

In this article, computer‐aided design of a broadband single balanced waveguide mixer covering full K‐band (18 to 26.5 GHz) is presented.Emphasis has been given on simple design approach of the mixer using commercially available CAD (computer‐aided design) tools. The mixer circuit is implemented on suspended stripline etched on soft substrate that is integrated with RF (radio frequency) and LO (local oscillator) waveguides. Conversion loss of 6–8 dB with 8.5 GHz instantaneous IF (intermediate frequency) bandwidth has been achieved with +10 dBm LO power at 35 GHz and the RF swept from 18 to 26.5 GHz. A systematic design approach of the mixer is presented with its simulated and experimental results. © 2011 Wiley Periodicals, Inc. Microwave Opt Technol Lett 53:586–588, 2011; View this article at wileyonlinelibrary.com. DOI 10.1002/mop.25759
A novel planar inverted‐F antenna (PIFA) for WLAN/WiMAX applications
Authors: Ojaroudi M. , Hassanpour M. , Ghobadi Ch. , Nourinia J.
Published: January 2011

A novel planar inverted‐F antenna (PIFA) for WLAN and WiMAX applications is presented. The proposed antenna with small size of 24 × 3 mm2, consists of rectangular radiating patch with T‐shaped notch and a notched ground plane with rectangular slot which provides a usable fractional bandwidth of 4.95–5.91 GHz. © 2011 Wiley Periodicals, Inc. Microwave Opt Technol Lett 53:649–652, 2011; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.25762
1D Koch fractal electromagnetic bandgap microstrip structures with r/a ratios higher than 0.5
Authors: Ruiz Juan de Dios , Martínez Félix L. , Hinojosa Juan
Published: January 2011

A 1D Koch fractal electromagnetic bandgap (KFEBG) microstrip structure is proposed.It is conceived by replacing the conventional holes etched in the ground plane of a microstrip line by level‐1 Koch fractal cell geometries, which have been obtained from a hexagonal shape. In the case of the conventional 1D electromagnetic bandgap (EBG) microstrip structure with periodic hole pattern, the design is limited to r/a ratios lower than 0.45, whereas the proposed pattern allows achieving r/a ratios higher than 0.5. It is shown that the conventional EBG and KFEBG microstrip structures behave as a stopband filter as r/a < 0.45. However, for r/a = 0.55, the measurements have confirmed that the 1D KFEBG microstrip structure presents a ultra‐wide stopband and, therefore, the proposed structure with r/a > 0.5 can be useful for the design of low‐pass filters. © 2011 Wiley Periodicals, Inc. Microwave Opt Technol Lett 53:646–649, 2011; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.25763
Cross slot multifrequency patch antennas
Authors: Lolit Kumar Singh L. , Gupta Bhaskar , Sarkar Partha P. , Yoshitomi K. , Yasumoto K.
Published: January 2011

Two simple single layer single feed cross slot patch antennas with air dielectric (εr = 1) substrate providing multiple frequency operation is proposed.At first a cross slot rectangular patch antenna providing quad frequency operation is proposed and experimentally studied. The measured quad frequencies are 1.93, 2.57, 3.18, and 3.56 GHz. Another cross slot trapezium patch antenna providing quad frequency operation is proposed and experimentally studied. The measured quad frequencies are at 1.43, 1.81, 2.97, and 3.58 GHz. Trapezium patch antenna is found to be more compact in size and as well as reduction in resonant frequency compared to rectangular patch antenna. Measured values are in good agreement with simulated results. The measured radiation patterns at each measured resonant frequency are also shown. © 2011 Wiley Periodicals, Inc. Microwave Opt Technol Lett 53:612–615, 2011; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.25765
Wide‐band ÷3 injection locked frequency divider in 0.35 μm SiGe BiCMOS
Authors: Jang Sheng‐Lyang , Hsu Chun‐Wei , Chang Chia‐Wei , Hsue Ching‐Wen
Published: January 2011

A wide‐band ÷3 injection locked frequency divider (ILFD) has been proposed, and it is based on a single‐stage voltage‐controlled oscillator with active‐inductor and HBT diodes, and was fabricated in the 0.35 μm silicon‐germanium 3P3M BiCMOS technology. The ILFD has wide operation range and was performed by injecting a differential signal to the bases of the injection HBTs. At the supply voltage VDD = 1.8 V, the oscillation frequency of the ILFD with two tuning voltages is tunable from 4.17 to 2.12 GHz, and at the incident power of 0 dBm, the ÷3 operation range is 5.93 GHz, from the incident frequency 6.3 to 12.23 GHz. The die area is 0.59 × 0.63 mm2. © 2011 Wiley Periodicals, Inc. Microwave Opt Technol Lett 53:609–611, 2011; View this article at wileyonlinelibrary.com. DOI 10.1002/mop.25771
A 33% tuning range voltage‐controlled oscillator robust to environmental variation
Authors: Jang Sheng‐Lyang , Chen Yu‐Sheng , Liu Cheng‐Chen , Juang Miin‐Horng
Published: January 2011

A low‐voltage differential voltage‐controlled oscillator (VCO) is designed and implemented in a 90‐nm CMOS 1P9M process.The designed circuit topology is an nMOS‐core cross‐coupled LC‐tank VCO robust to process, voltage and temperature variation. At the supply voltage of 0.4 V, the output phase noise of the VCO is −108.78 dBc/Hz at 1‐MHz offset frequency from the carrier frequency of 10.13 GHz, and the figure of merit is −187.68 dBc/Hz. The power consumption is 1.32 mW. Tuning range is about 3.62 GHz, from 9.15 to 12.77 GHz, while the control voltage was tuned from 0 to 1.0 V. © 2011 Wiley Periodicals, Inc. Microwave Opt Technol Lett 53:517–519, 2011; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.25775
Design of a 9 GHz CMOS low noise amplifier using gain‐enhanced technique
Authors: Wang Sen
Published: January 2011

In this article, a 9 GHz low noise amplifier (LNA) using gain‐enhanced technique is presented. The compact and high‐gain LNA with cascode topology is implemented in a standard 0.18‐μm CMOS process. The gain‐enhanced technique consists of two inductors in the common gate (CG) stage of the cascode configuration. The first inductor at the source terminal in the CG stage eliminates the parasitic effects caused by the parasitic capacitances of transistors at high frequencies. Moreover, the second inductor at the gate terminal in the CG stage achieves a negative resistance making a high gain characteristic of the amplifier. Finally, the measured small signal gain, noise figure and inputP1dBat 9 GHz are 16.5 dB, 4.5 dB, and −15 dBm, respectively. The chip size of the compact LNA is 0.48 mm × 0.8 mm including all testing pads. © 2011 Wiley Periodicals, Inc. Microwave Opt Technol Lett 53:479–481, 2011; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.25778
A K‐band balanced subharmonically pumped image rejection mixer using 0.15‐μm GaAs pHEMT technology
Authors: Ke Po‐Yu , Chiu Hsien‐Chin , Kuo Che‐Yu , Fu Jeffrey S. , Chiang Yi‐Chyun
Published: January 2011

This work presents a K‐band balance single side‐band subharmonically pumped image rejection diode mixer (SHIRM).It uses lumped elements and three‐conductor‐line quadrature couplers and is fabricated in a 0.15‐μm GaAs process. The SHIRM is realized in size reduction by using two antiparallel diode pairs for frequency mixing. The three‐conductor‐line bending coupler is 55% reduction in size compared to the nonbending one for radio frequency port, and lumped elements realization is 62% smaller in size than the quarter‐wavelength line for local oscillator port. The proposed circuit with a symmetric layout provides good matches on amplitude and phase performances. The measured results exhibit a minimum conversion loss of 13 dB, a maximum image rejection ratio of 19 dB. All ports isolations are better than 10 dB. The chip area is only 1.5 × 1 mm2. © 2011 Wiley Periodicals, Inc. Microwave Opt Technol Lett 53:485–488, 2011; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.25781
Candelabra shaped microstrip antenna for ultra‐wideband applications
Authors: Haraty Mohammad Reza , Momeni Seyed Majid Seyed , Sadeghzadeh R. A.
Published: January 2011

This article presents the results of a novel and compact microstrip antenna having a candelabra geometry, which exhibits ultra‐wideband (UWB) performance when excited using coplanar waveguide feed. The proposed antenna exhibits an impedance bandwidth of 138% from 2.3 to 12.7 GHz, exceeding Federal Communication Commission's ultra‐wideband frequency range with a return‐loss performanceS11= −10 dB. The antenna radiates omnidirectionally in theH‐plane and bidirectionally inE‐plane. Details of the antenna's design and simulation results are presented and validated with practical measurements. © 2011 Wiley Periodicals, Inc. Microwave Opt Technol Lett 53:669–672, 2011; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.25783
Four‐channel incoherent mimo transmission over 4.4‐km MM fiber
Authors: Kowalczyk Marcin , Siuzdak Jerzy
Published: January 2011

The article presents realization of four‐channel incoherent MIMO system operating over GI MM fiber with 50‐μm core. The quality of the received channels was good. The selection of the carrier frequency has little impact on the system operation. © 2011 Wiley Periodicals, Inc. Microwave Opt Technol Lett 53:502–506, 2011; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.25791
Low‐phase noise oscillator using spurline resonator for I‐band applications
Authors: Shrestha B. , Kim N. Y.
Published: January 2011

This letter presents two compact L‐type spurline and meander spurline resonators and their application to low‐phase noise oscillators. These resonators have a bandstop characteristic that can be used in the series feedback oscillator topology. Both miniaturized resonators consist of a defected L‐type spurline and a meander spurline with inductive characteristics and a loaded stub with capacitive characteristics. The structure of resonators reduces the required the circuit area as well as the cost. The oscillators, using the spurline and the meander spurline resonators, show excellent phase noise performances of −96.23 dBc/Hz and −103.23 dBc at a 100 kHz offset from the carrier frequency of 9.0 GHz and 9.2 GHz with an output power of 14.47 dBm and 15.23 dBm, respectively. The later oscillator exhibited better phase noise characteristics due to the high Q value of the defected meander spurline resonator. © 2011 Wiley Periodicals, Inc. Microwave Opt Technol Lett 53:543–547, 2011; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.25803
Gain‐enhanced linearly tapered slot antenna with half‐circular slotted side edges
Authors: In Dae‐Myoung , Pyo Seongmin , Lee Min‐Jae , Kim Young‐Sik
Published: January 2011

In this article, a new linearly tapered slot antenna (LTSA) with half‐circular slots (HCSs) embedded on both edge‐sides is proposed for improving antenna gain. The side lobe levels of the LTSA are lowered as these HCSs may alter the surface current intensities on both edge‐sides. As the half‐circular size is increased, the 3‐dB beamwidths of the proposed antenna are decreased in E‐ and H‐plane, respectively. The measured gain is improved in a whole Ku‐band (12.4–18.5 GHz), and it has a maximum gain of 14.8 dB at the design frequency of 15 GHz. © 2011 Wiley Periodicals, Inc. Microwave Opt Technol Lett 53:686–688, 2011; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.25818
Erratum: To compact branch‐line couplers using parallel high‐impedance transmission lines
Authors: Khalaj‐Amirhosseini Mohammad , Yazdani Mohsen
Published: January 2011

Originally published Microwave Opt Technol Lett 52: 1996–1999, 2010. © 2011 Wiley Periodicals, Inc. Microwave Opt Technol Lett 53:700–700, 2011; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.25843

(Original article DOI 10.1002/mop.25369)
Magnetic resonance microimaging of human skin vasculature in vivo at 3 Tesla
Authors: Laistler Elmar , Loewe Robert , Moser Ewald
Published: January 2011

MRI can be used to investigate human skin microvasculature in vivo, provided adequate spatial resolution. Therefore, the sensitivity of the experiment has to be optimized to achieve sufficient signal‐to‐noise ratio (SNR) within reasonable measurement time to minimize motion artifacts, improve patient comfort and save costs. In this work, the high sensitivity of a 15 mm surface coil and the signal strength of a 3 Tesla scanner, together with a three‐dimensional gradient echo sequence and post‐processing have been combined to obtain high SNR. Images of human skin with isotropic spatial resolution of 100 μm were acquired within 10 min and the cutaneous vasculature could be visualized in 3D [Correction made here after initial online publication.], based on three averaged scans. The presented method can be used for diagnosis and, due to its non‐invasiveness, treatment monitoring of vascular pathologies in the skin, such as inflammation, vascular malformation, or neoangiogenesis in superficial tumors. Magn Reson Med, 2011. © 2011 Wiley‐Liss, Inc.
Combining phase images from multi‐channel RF coils using 3D phase offset maps derived from a dual‐echo scan
Authors: Robinson Simon , Grabner Günther , Witoszynskyj Stephan , Trattnig Siegfried
Published: January 2011

A method is presented for the combination of phase images from multi‐channel RF coils in the absence of a volume reference coil. It is based on the subtraction of 3D phase offset maps from the phase data from each coil. Phase offset maps are weighted combinations of phase measurements at two echo times. Multi‐Channel Phase Combination using measured 3D phase offsets (MCPC‐3D) offers a conceptually and computationally simple solution to the calculation of combined phase images. The dual‐echo data required for the phase maps can be intrinsic to the high‐resorlution gradient‐echo scan to be reconstructed (MCPC‐3D‐I). Alternatively, a separate, fast, low‐resolution dual‐echo scan can be used (MCPC‐3D‐II). Both variants are shown to give near perfect phase matching, yielding images with high SNR throughout and high GM‐WM contrast. MCPC‐3D is compared with other reference‐free phase image crombination methods; high‐pass phase filtering, phase difference imaging, and matching using constant offsets (MCPC‐C). Multi‐Channel Phase Combination using measured 3D phase offsets method does not need an overlap between the signals from individual coils and can be used with parallel imaging, making it ideally suited to multi‐channel coils with a large number of elements, and to high and ultra‐high field systems. Magn Reson Med, 2011. © 2011 Wiley‐Liss, Inc.
Enhancement effects of hepatic dynamic MR imaging at 3.0 T and 1.5 T using gadoxetic acid in a phantom study: comparison with gadopentetate dimeglumine
Authors: Morita Kosuke , Namimoto Tomohiro , Awai Kazuo , Komi Masanori , Hashida Masahiro , Tsuji Takashi , Hirai Toshinori , Yamashita Yasuyuki
Published: January 2011

To identify the optimum sequence at gadoxetic acid enhanced hepatic dynamic magnetic resonance imaging in the arterial phase, we studied phantoms that contained gadoxetic acid or gadopentetate dimeglumine diluted in human blood. We obtained magnetic resonance images at 3.0 T and 1.5 T with one vendor (Siemens) using 3D‐gradient echo (GRE)‐, 2D‐fast low angle shot (FLASH)‐, and turbo spin echo sequences. Contrast ratio was highest for 3D‐GRE; at both 3.0 T and 1.5 T it was superior when the contrast agent was gadoxetic acid. With both gadoxetic acid and gadopentetate dimeglumine, contrast ratio peaked at around 5‐and 2 mmol/L on 3D‐GRE‐ and 2D‐FLASH images, respectively. Compared with gadopentetate dimeglumine, at 3.0 T, the peak contrast ratio of gadoxetic acid was 14.1% better on 3D‐GRE images and 14.0% better on 2D‐FLASH images; at 1.5 T it was 16.4% better on 3D‐GRE‐ and 5.7% better on 2D‐FLASH images. With respect to the magnetic field strength, at 3.0 T the peak contrast ratio of gadoxetic acid was 6.0% better than at 1.5 T on 3D‐GRE images and 49.5% better on 2D‐FLASH images; it was 8.5% better on 3D‐GRE‐ and 44.6% better on 2D‐FLASH images than when the contrast agent was gadopentetate dimeglumine. Thus, gadoxetic acid yielded better enhancement on 3D‐GRE images acquired at 3.0 T than at 1.5 T and enhancement was better than that obtained with gadopentetate dimeglumine at the same concentration. Magn Reson Med 66:213–218, 2011. © 2011 Wiley‐Liss, Inc.
Effects of electrical stimulation on neuromuscular junction morphology in the aging rat tongue
Authors: Johnson Aaron M. , Connor Nadine P.
Published: January 2011

Alterations in neuromuscular junction (NMJ) structure in cranial muscles may contribute to age‐related deficits in critical sensorimotor actions such as swallowing. Neuromuscular electrical stimulation (NMES) is used in swallowing therapy, but it is unclear how NMJ structure is affected or if NMJ morphology is best measured in two or three dimensions. Two‐ and three‐dimensional measurements of NMJ morphology in the genioglossus muscle were compared in rats that had undergone 8 weeks of hypoglossal nerve stimulation vs. untreated controls. The relationship between motor endplate volume and nerve terminal volume had a mean positive slope in 90% of the young adult controls, but it was positive in only 50% of the old controls; 89% of NMES old rats had a positive slope. NMJ measurements were more accurate when measured in three dimensions. In the NMJ, aging and NMES are associated with changes in the pre‐ and post‐synaptic relationship. Muscle Nerve 43: 203–211, 2011
Time‐course of changes in the myonuclear domain during denervation in young‐adult and old rat gastrocnemius muscle
Authors: van der Meer Sander F.T. , Jaspers Richard T. , Jones David A. , Degens Hans
Published: January 2011

If myonuclear loss initiates muscle wasting, it should precede the loss of muscle mass. As aging affects muscle plasticity, the time‐course of muscle atrophy during disuse may differ between young and old animals. To investigate this, gastrocnemius muscles of 5‐ and 25‐month‐old rats were exposed to 1, 2, or 4 weeks of denervation, whereas the contralateral gastrocnemius muscles served as controls. Muscle fibers of each type responded similarly to 4 weeks of denervation. For both ages most of the atrophy (36%; P < 0.001) occurred in the first 2 weeks. In young‐adult muscles, the myonuclear number remained constant, but in old muscles it decreased to below control level after 4 weeks of denervation (P < 0.05). Despite this differential response, myonuclear domain size decreased similarly at both ages (P < 0.001). In both young‐adult and old rats, denervation‐induced atrophy was not preceded by a loss of myonuclei. Muscle Nerve 43: 212–222, 2011
Spinal reflex excitability and homosynaptic depression after a bout of whole‐body vibration
Authors: Kipp Kristof , Johnson Samuel T. , Doeringer Jeffrey R. , Hoffman Mark A.
Published: January 2011

Although whole‐body vibration (WBV) affects neuromuscular performance, it remains unclear whether the effects are due to spinal reflex potentiation or inhibition, or differ between muscle groups. This study aimed to identify the effect of WBV on measures of spinal reflex excitability (H‐reflex) and homosynaptic depression (HD) in the soleus (SOL) and medial gastrocnemius (MG) muscles. H‐reflex and HD measurements were made in the SOL and MG muscle of 20 participants before and after a bout of WBV. H‐reflex and HD were measured every 15 seconds for 10 minutes post‐WBV and averaged at 1‐minute increments. H‐reflex amplitude was depressed for the first minute post‐vibration, whereas the effect of HD was reduced for the first 2 minutes post‐vibration. WBV significantly decreases spinal reflex excitability and HD, but it does so transiently and independent of muscle group. Muscle Nerve 43: 259–262, 2011
Impaired respiratory function in mdx and mdx/utrn+/− mice
Authors: Huang Ping , Cheng Georgiana , Lu Haiyan , Aronica Mark , Ransohoff Richard M. , Zhou Lan
Published: January 2011

Muscle fibrosis is a prominent pathological feature that directly causes muscle dysfunction in Duchenne muscular dystrophy (DMD). The DMD mouse models, mdx mice and mdx mice with haploinsufficiency of the utrophin gene (mdx/utrn+/−), display progressive diaphragm fibrosis. We performed unrestrained whole‐body plethysmography (WBP) in mdx and mdx/utrn+/− mice, and compared them with wild‐type controls. Respiratory function gauged by respiratory frequency, tidal volume, minute volume, peak inspiratory flow, and peak expiratory flow was significantly impaired in the mdx mice. Consistent with more severe diaphragm fibrosis in the mdx/utrn+/− mice, respiratory impairment was worse than in mdx mice at 6 months. WBP is useful for monitoring in vivo respiratory function of mdx and mdx/utrn+/− mice, and it may serve as an outcome measurement for therapies that target diaphragm fibrosis. The mdx/utrn+/− mouse model may be better than the mdx model for testing antifibrotic therapies, especially at the severe stage. Muscle Nerve 43: 263–267, 2011
Acute superficial sensory neuropathy with generalized anhidrosis, anosmia, and ageusia
Authors: Miyazaki Yu , Koike Haruki , Ito Mizuki , Atsuta Naoki , Watanabe Hirohisa , Katsuno Masahisa , Kusunoki Susumu , Sobue Gen
Published: January 2011

We report a 53‐year‐old woman with an unusual presentation characterized by acute onset of generalized sensory symptoms associated with anhidrosis, anosmia, ageusia, and elevated titers of anti–GalNAc‐GD1a antibodies. After intravenous immunoglobulin therapy, a remarkable improvement in the pain and temperature sensation was noted in her face, trunk, and extremities. The impaired pain and temperature sensation remained distributed along cranial and spinal dermatomes in a non–length‐dependent manner, suggesting that the ganglionopathy affected small neurons. Muscle Nerve 43:287–289, 2011
Physiological properties of malignant tumours
Authors: Vaupel P.
Published: January 2011

It is generally accepted that tumour microcirculation, blood flow, oxygen and nutrient supply, tissue pH distribution, and the bioenergetic status—factors which are usually closely linked and which define the so‐called metabolic microenvironment—can markedly influence the therapeutic response of malignant tumours to conventional irradiation, chemotherapy, other non‐surgical treatment modalities, and the cell proliferation activity within the tumours. Currently available information on the parameters defining the metabolic micromilieu in human tumours is presented in this paper. According to these data, significant variations in these relevant factors are likely to occur between different locations within a tumour, and between tumours of the same grading and clinical staging. Therefore, evaluation of the metabolic microenvironment in individual tumours before therapy and a corresponding ‘fine‐tuning’ of treatment protocols for individual patients may result in an improved tumour response to treatment.
Phospholipid metabolites as indicators of cancer cell function
Authors: Ruiz‐Cabello Jesús , Cohen Jack S.
Published: January 2011

NMR methods are being applied to study phospholipid metabolism of cancer cells by monitoring the resonances which appear in the31P spectrum. This review, aside from considering the applicability of NMR to this specific pathway, raises the question of whether the phospholipid metabolite peaks observed by MR are indicators of cancer cell function or tumor response to treatment. After assessing the results from many investigations, it is concluded that there is no clear correlation and that a combination of techniques, includingin vitroand extract studies, will be necessary for a more comprehensive evaluation of thein vivodata.
On the interpretation of proton NMR spectra from brain tumours in vivo and in vitro
Authors: Bruhn H. , Michaelis T. , Merboldt K. D. , Hänicke W. , Gyngell M. L. , Hamburger C. , Frahm J.
Published: January 2011

Localized proton NMR spectroscopy in vivo allows focal studies of cerebral metabolites in both man and laboratory animals from image‐defined regions as small as 1 mL or 64 μL, respectively. Although brain tumours lead to remarkable spectral alterations relative to normal brain, a number of problems may compromise the interpretation of the results. Potential complications arise from the chosen experimental conditions (method, TE, size and location of volume of interest), from regional metabolic heterogeneity in and around tumours, from differences between human tumours and animal models, and from discrepancies between in vivo and in vitro findings. Strategies and pitfalls are illustrated with use of selected examples from primary brain tumours, a rat tumour model and perchloric acid extracts of resected specimens.
In vivoandex vivomagnetic resonance spectroscopy as applied to pharmacokinetic studies with anticancer agents: a review
Authors: Newell David R. , Maxwell Ross J. , Golding Bernard T.
Published: January 2011

The potential role of MRS in studying the pharmacokinetics of anticancer drugs is reviewed.In vivoandex vivoMRS has been used extensively in studies with fluoropyrimidines. Results from preclinical models have demonstrated that biochemical modulation of 5‐fluorouracil metabolism can be demonstrated by MRS. The more general potential of MRS is illustrated by studies with the antifolate CB3988 (C2‐desamino‐C2‐methyl‐N10‐propargyl‐2′‐trifluoromethyl‐5,8‐dideazafolic acid). Studies in mice and rats have shown that hepatobiliary clearance and renal elimination can be measured non‐invasively by MRS. Comparison of half‐lives derived from MRS and high performance liquid chromatography data gave reasonable agreement. In addition, MRI was used to localize drug‐derived material within the abdominal cavity. The application ofex vivoMRS is illustrated by studies on the urinary excretion of platinum complexes.1H‐MRS has been used to demonstrate the presence of the cyclobutanedicarboxylate leaving group, both free and platinum bound, in the urine of patients treated with carboplatin. With iproplatin195Pt NMR has been used to demonstratein vivoreduction of this Pt(IV) complex to Pt(II) complexes. Finally, the application of MRS to the study of the molecular pharmacology of alkylating agents (a nitrogen mustard andN‐methyl‐N‐nitrosourea) is discussed.
1H NMR spectroscopy of subcutaneous tumors in mice: Preliminary studies of effects of growth, chemotherapy and blood flow reduction
Authors: Shungu Dikoma C. , Bhujwalla Zaver M. , Wehrle Janna P. , Glickson Jerry D.
Published: January 2011

This study evaluates a number of methods for obtaining 1H NMR spectra with adequate suppression of lipid and water resonances in two subcutaneously implanted transplantable tumor models (RIF‐1 and EMT6/SF). Spin‐echo spectra with long TEs (270 ms; water suppressed by presaturation) eliminated lipid resonances from 1H spectra of RIF‐1 and decreased lipid contamination in spectra of EMT6/SF; however, spectral sensitivity was substantially reduced. A shorter TE (135 ms) increased sensitivity but did not result in adequate suppression of the lipid peaks. In RIF‐1, but not EMT6/SF, adequate lipid suppression was achieved by: (i) spatially selective presaturation of lipid, which in this tumor (but not in EMT6/SF) was localized in a thin region along the periphery of the tumor, followed by a 1‐D spin‐echo chemical shift imaging pulse sequence (TE = 135 ms); and (ii) 2‐D spin‐echo chemical shift imaging (TE = 270 ms; ∼2 × 2 × 9 mm3 voxels). Preliminary 1H studies of the RIF‐1 tumor indicate that: (i) there are no significant changes in metabolite levels relative to tumor water during 4 days of untreated tumor growth; (ii) tumor response to chemotherapy with 5‐fluorouracil results in a decrease in intensity of all metabolite 1H resonances relative to tumor water, with total choline decreasing the most and lactate the least; and (iii) acute tumor blood flow reduction induced by administration of hydralazine results in doubling of the lactate intensity relative to water. These experiments demonstrate that in vivo 1H spectroscopy is feasible in at least one commonly employed subcutaneous tumor model (RIF‐1) and that this nucleus holds considerable promise for clinical and experimental studies of tumors.
Studies of human tumors by MRS: A review
Authors: Negendank William
Published: January 2011

The literature describing 31P, 1H, 13C, 23Na and 19F MRS in vivo in human cancers is reviewed. Cancers have typical metabolic characteristics in 31P and 1H MRS including high levels of phospholipid metabolites and a cellular pH more alkaline than normal. These alone are not specific for cancer but are diagnostic in appropriate clinical settings. Some metabolic characteristics appear to be prognostic indices and correlation with treatment response is emerging as an important potentially cost‐effective use of MRS in oncology. 19F MRS examines pharmacokinetics of 5‐fluorouracil and by demonstrating its retention predicts response of a cancer to treatment. Current needs include improvement of diagnostic specificity by use of techniques like multivoxel MRS, proton decoupling of 31P, short echo time and fat‐suppressed 1H MRS, 13C MRS direct or via 1H‐observe, and statistical analysis of multiple spectral features. Trials in large populations in well defined clinical settings are needed to determine if MRS can provide independent prognostic indices useful in cancer management.
Disturbed dental development of permanent teeth in children with solid tumors and lymphomas
Authors: Cubukcu Cigdem Elbek , Sevinir Betül , Ercan İlker
Published: January 2011

Background

Deficient dental root development has been reported after conventional pediatric anticancer therapy but less information is available on children with solid tumors and lymphomas.

Procedure

We examined dental development from panoramic radiographs (PRGs) of 37 childhood cancer survivors (CCS) treated under the age of 10 years with multimodal chemotherapy (CT) and/or head and neck radiotherapy (RT). A novel defect index (DeI) was used to describe the total damage to permanent dentition. The DeI was also tested in matched controls.

Results

All CCS had dental disturbances including abnormal root development (86.4%), microdontia (13.5%) and tooth agenesis (16.2%). Testing the controls gave the mean DeI value 1.9 ± 2.7 (range, 0–12), while the index scores in the study group varied from 0 to 49 (mean 10.8 ± 11.2) (P < 0.01). The statistical differences in the mean DeI values were insignificant between CT and CT and RT groups (P > 0.05).

Conclusions

Children treated for solid tumors and lymphomas are at considerable risk of some disturbances in developing dental structures. RT increased the severity of disturbances induced by CT. Studies should further elucidate dose‐, age and time‐related effects of anticancer treatment on dental development. Pediatr Blood Cancer 2012; 58: 80–84. © 2011 Wiley Periodicals, Inc.
Multiple target molecular monitoring of bone marrow and peripheral blood samples from patients with localized neuroblastoma and healthy donors
Authors: Corrias Maria Valeria , Haupt Riccardo , Carlini Barbara , Cappelli Enrico , Giardino Stefano , Tripodi Gino , Tonini Gian Paolo , Garaventa Alberto , Pistoia Vito , Pistorio Angela
Published: January 2011

Background

Multiple target molecular monitoring of minimal residual disease in neuroblastoma (NB) patients may increase sensitivity and overcome tumor heterogeneity. However, multiple target analysis is costly and time consuming, thus improvement with respect to single target monitoring needs to be achieved.

Procedures

Italian patients with localized NB were evaluated at diagnosis for TH, GD2‐s, DDC, DCX, ELAV‐4, STX, and Phox2b mRNA expressions. Patients with metastatic NB were tested as positive controls, together with NB primary tumors and cell lines, while healthy donors were tested as negative controls.

Results

All NB‐related markers but Phox2b were expressed in healthy donors, and in a high percentage of patients with localized NB without association with clinical events. The introduction of cut‐off levels increased marker specificity, although the percentage of positive results was only slightly modified. While TH positivity in PB samples significantly associated with a worse prognosis, a paradox association was found for GD2‐s mRNA expression. No correlation and agreement between quantitative and qualitative results obtained with the two assays were found. In the set of samples tested for all markers, no pattern of expression was found to be associated with a specific clinical situation.

Conclusion

These findings suggest that positive molecular results may not reflect the presence of disease, and that correlation among different markers is small in condition of low tumor burden. Thus, to reduce cost and amount of precious samples, in addition to TH, whose prognostic value was confirmed, only Phox2b warrants further evaluation in multi‐center, prospective studies for high risk patients. Pediatr Blood Cancer 2012; 58: 43–49. © 2011 Wiley Periodicals, Inc.
The utility of performing the initial lumbar puncture on day 8 in remission induction therapy for childhood acute lymphoblastic leukemia: TCCSG L99‐15 study
Authors: Hasegawa Daisuke , Manabe Atsushi , Ohara Akira , Kikuchi Akira , Koh Katsuyoshi , Kiyokawa Nobutaka , Fukushima Takashi , Ishida Yasushi , Saito Tomohiro , Hanada Ryoji , Tsuchida Masahiro ,   The Tokyo Children's Cancer Study Group
Published: January 2011

Background

Traumatic lumbar puncture with leukemic blasts (TLP+), which has been reported to occur 5–10%, in the previous studies, adversely affects the outcome of children with acute lymphoblastic leukemia (ALL). Based on the results from our previous study, we deferred the initial lumbar puncture until day 8 in remission induction therapy in order to reduce the frequency of cases with TLP+.

Procedure

The study was conducted as a prospective cohort study within the Tokyo Children's Cancer Study Group (TCCSG) L99‐15 study. Between April 1999 and June 2003, 754 children with newly diagnosed ALL enrolled. The patients received the initial intrathecal chemotherapy after 7 days of prednisolone treatment. The incidence of central nervous system (CNS)‐positive (the presence of leukemic blasts in cerebrospinal fluid or cranial nerve palsy) including TLP+ cases and cumulative incidence of CNS relapse were examined.

Results

The incidence of CNS‐positive and TLP+ was 2.9% (n = 22) and 0.8% (n = 6), respectively. These incidences were much lower than those in the representative study groups employing the initial IT on day 1. Of 22 patients with CNS‐positive, only one patient relapsed in CNS, whereas 22 of the remaining CNS‐negative 723 patients suffered from CNS relapse. Overall, event‐free survival at 4 year was 78.2 ± 1.6%. Four‐year cumulative incidence of any CNS relapse was 3.3 ± 0.7%, which improved from our previous study in spite of limiting the use of cranial irradiation.

Conclusions

Our strategy reduced the frequency of CNS‐positive patients who required reinforcement of CNS‐directed therapy without compromising overall outcome. Pediatr Blood Cancer 2012; 58: 23–30. © 2011 Wiley Periodicals, Inc.
The epidemiology of herpes zoster in 226 children with acute lymphoblastic leukemia
Authors: Sørensen Gitte Vrelits , Rosthøj Steen , Würtz Morten , Danielsen Tore Kristian , Schrøder Henrik
Published: January 2011

Background

Herpes zoster (HZ) is rare in healthy children, but may occur frequently and take a complicated course in children receiving chemotherapy. We determined the morbidity related to HZ in children with acute lymphoblastic leukaemia (ALL).

Procedure

Medical records of 226 children diagnosed with ALL were reviewed. Of these, 160 were seropositive at the time of diagnosis. HZ eruptions during primary chemotherapy, during therapy for relapse and following bone marrow transplantation (BMT) were registered.

Results

A total of 90 eruptions were recorded: 63 first‐time attacks and 27 recurrent episodes among 14 children. All eruptions were treated with acyclovir (ACV) and in 60% it was given intravenously. Cutaneous dissemination occurred in 11 cases, post herpetic neuralgia in five, visceral dissemination in none. During primary chemotherapy 47 children (29%) had HZ. The eruption rate was significantly higher in children on high risk protocols compared to children on standard/intermediate risk protocols (0.36 vs. 0.07/0.09 per year) and was related to intensity of chemotherapy. During therapy for relapse 7 of 29 (24%) had a total of 13 eruptions. Following BMT 9 of 26 (35%) had a total of 10 eruptions.

Conclusion

Almost one third of the seropositive children had HZ during primary chemotherapy. Of those treated on high risk protocols more than half had one or more eruptions during the course of treatment. The risk of complicated HZ is small, but prolonged intensive chemotherapy can lead to considerable morbidity from repeated eruptions. Attempts to improve immunity by vaccination after attaining remission seem warranted. Pediatr Blood Cancer 2011; 57: 993–997. © 2011 Wiley‐Liss, Inc.
Two Superordinate Personality Factors in Childhood
Authors: Slobodskaya Helena R.
Published: January 2011

The study presents the superordinate structure of personality measured by the Inventory of Child Individual Differences (ICID) and its links with behavioural approach system (BAS) and behavioural inhibition system (BIS), problem behaviour and family environment measures in parent reports of 1780 Russian children aged 3–17 years and 573 adolescent self–reports. Two higher–order factors, α comprising Agreeableness, Conscientiousness and Neuroticism (reversed), and β comprising Openness, Extraversion, Conscientiousness and Emotional Stability, were confirmed across gender and age. Structural model linking BAS with α and BIS with β was supported. α was negatively associated with externalising problems and β was negatively related to internalising problems. The links with family cohesion, punishment, westernisation and affluence supported the external validity of the Big Two. Copyright © 2011 John Wiley & Sons, Ltd.
Isotopic composition of syngenetic ice wedges and palaeoclimatic reconstruction, western Taymyr, Russian Arctic
Authors: Streletskaya Irina , Vasiliev Alexander , Meyer Hanno
Published: January 2011

Recent, Holocene and Late Weichselian (Sartan) generations of syngenetic ice wedges developed in loess‐like and alluvial sediments were investigated along the coast of the Yenisey Bay from Sopochnaya Karga Cape (71°88'N, 82°68'E) to Dikson (73°31'N, 80°34'E). Ages of about 3.4 − 4.6 ka BP were determined for peat layer and wood fragments in ice‐rich deposits surrounding ice wedges near Dikson. The isotopic composition of these wedges reflects relatively cold winter temperatures in the Holocene. The lightest isotope composition characterises older ice wedges near Dikson and Sopochnaya Karga Cape. A warming trend between ice wedges of different generations was indicated by a distinct increase in O (4 − 5 ‰) and H (35 − 40‰) stable isotopes. Palaeotemperature reconstruction based on the data shows that winter temperatures during the formation of older generation ice wedges were lower than Holocene winter temperatures, indicating that they developed in the Late Weichselian (MIS2). The presence of syngenetic ice wedges strongly suggests that the coast of western Taymyr was not ice‐covered at this time. Copyright © 2011 John Wiley & Sons, Ltd.
Biological effects of rice harbouring Bph14 and Bph15 on brown planthopper, Nilaparvata lugens
Authors: Li Jie , Chen Qiuhong , Wang Liangquan , Liu Jia , Shang Keke , Hua Hongxia
Published: January 2011

BACKGROUND: Brown planthopper (Nilaparvata lugens Stål; BPH) resistance genes Bph14 and Bph15 have been introgressed singly or pyramided into rice variety Minghui 63 (MH63). The antibiosis and antixenosis effects of these rice lines on BPH and the expression of five P450 genes of BPH regulated by these rice lines were investigated in this study.

RESULTS: The resistance level of rice lines harbouring resistance genes was improved compared with MH63. MH63::14 (carrying Bph14) had negative effects on the development of males, honeydew excretion of females, the female ratio and the copulation rate compared with MH63. MH63::14 also exhibited antixenosis action against BPH nymphs, female adults and oviposition. Besides these negative effects, MH63::15 (carrying Bph15) could also retard the development of females, lower the fecundity and shorten the lifespan of females. The antixenosis action of MH63::15 was stronger than that of MH63::14. When Bph14 and Bph15 were pyramided, antibiosis and antixenosis effects were significantly enhanced relative to single‐introgression lines. Among the five P450 genes of BPH, expression of three genes was upregulated, one gene was downregulated and one gene was unchanged by resistant hosts.

CONCLUSION: Both Bph14 and Bph15 could improve resistance levels of MH63. MH63::15 and MH63::14&15 had greater potential to control BPH infestations than MH63::14. Copyright © 2011 Society of Chemical Industry
Synthesis of peptides containing 5‐hydroxytryptophan, oxindolylalanine, N‐formylkynurenine and kynurenine
Authors: Todorovski Toni , Fedorova Maria , Hennig Lothar , Hoffmann Ralf
Published: January 2011

ROS, continuously produced in cells, can reversibly or irreversibly oxidize proteins, lipids, and DNA. At the protein level, cysteine, methionine, tryptophan, and tyrosine residues are particularly prone to oxidation. Here, we describe the solid phase synthesis of peptides containing four different oxidation products of tryptophan residues that can be formed by oxidation in proteins in vitro and in vivo: 5‐HTP, Oia, Kyn, and NFK. First, we synthesized Oia and NFK by selective oxidation of tryptophan and then protected the ${\bf \alpha}$‐amino group of both amino acids, and the commercially available 5‐HTP, with Fmoc‐succinimide. High yields of Fmoc‐Kyn were obtained by acid hydrolysis of Fmoc‐NFK. All four Fmoc derivatives were successfully incorporated, at high yields, into three different peptide sequences from skeletal muscle actin, creatin kinase (M‐type), and ${\bf \beta}$‐enolase. The correct structure of all modified peptides was confirmed by tandem mass spectrometry. Interestingly, isobaric peptides containing 5‐HTP and Oia were always well separated in an acetonitrile gradient with TFA as the ion‐pair reagent on a C18‐phase. Such synthetic peptides should prove useful in future studies to distinguish isobaric oxidation products of tryptophan. Copyright © 2011 European Peptide Society and John Wiley & Sons, Ltd.
Improved photocatalytic performance of rutile TiO2
Authors: Nowotny Maria K. , Bahnemann Detlef W.
Published: January 2011

The photocatalytic degradation of the model compound methylene blue (MB) was used to monitor the photocatalytic performance of a sequence of undoped rutile TiO2 dispersions, processed under different conditions. In particular two types of powders – strongly reduced (BET = 1.69 m2/g) and strongly oxidised (BET = 0.75 m2/g) – were processed at 1273 K in a controlled oxygen atmosphere of p (O2) = 10–10 Pa and p (O2) = 75 kPa, respectively. Results demonstrate that the coupling of equal amounts of the strongly reduced and the strongly oxidised rutile TiO2 powders enhances the photo‐degradation of MB. This is the first time that the photocatalytic performance of rutile TiO2 has been enhanced through homogeneous coupling. The performance was further enhanced by the addition of an Fe2+ ion redox mediator. All results were compared to a commercial anatase TiO2 pow‐ der purchased from Millenium Chemicals (GP350; BET = 121.9 m2/g). (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Phase transformation mechanism of In–Sb–Te through the boundary reaction between InSb and InTe
Authors: Kim Yong Tae , Kim Eun Tae , Kim Chung Soo , Lee Jeong Yong
Published: January 2011

The boundary reaction between InSb and InTe bilayers shows that In3Sb1Te2 (IST) is formed at the InTe side first due to the diffusion of Sb atoms from InSb to InTe rather than the diffusion of Te atoms from InTe to InSb at the crystallization temperature of IST. The diffusion of Sb atoms into InTe changes the atomic configuration of InTe, which leads to small lattice distortion and a coherent boundary region for the formation of IST crystalline thin films. (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Wave activity and baroclinic stability theorems for a two‐dimensional stratified semi‐geostrophic model
Authors: Ren Shuzhan
Published: January 2011

Arnold's method is used to derive two finite‐amplitude wave‐activity invariants – pseudo‐momentum and pseudo‐energy – based on the Hamiltonian structure for the two‐dimensional baroclinic semi‐geostrophic (SG) model in physical coordinates. The corresponding Liapunov stability theorems are established. For small‐amplitude disturbances the pseudo‐momentum and pseudo‐energy can be greatly simplified by introducing the quasi‐potential‐vorticity perturbation. The corresponding linear stability conditions, expressed explicitly in terms of the basic state, are obtained. The lateral boundary conditions are found to have a big impact on the stability of SG dynamics in both linear and nonlinear cases.

The results show that nonlinear stability criteria are more complicated than linear stability criteria, in that they contain more conditions in the interior resulting from the inclusion of potential temperature and the nonlinearity of SG potential vorticity in the wave activity. It is also found that the nonlinear stability criteria for the SG model are very different from those for the quasi‐geostrophic (QG) model.

The failure to extend the Liapunov stability theorems to the three‐dimensional SG model is discussed. It is found that this failure results from the third‐order nonlinear terms in the three‐dimensional SG potential vorticity. Since the variation of these terms in the wave activity is not sign‐definite, nonlinear stability conditions cannot be obtained. Copyright © 2011 Royal Meteorological Society
Evaluation of a reduced model for investigating hurricane formation from turbulence
Authors: Schecter David A.
Published: January 2011

This paper evaluates the adequacy of a reduced (three‐layer) model for understanding hurricane formation from turbulent initial conditions. The evaluation is based on a direct comparison to tropical cyclogenesis in a cloud‐system‐resolving (CSR) model that employs single‐moment warm rain microphysics. The reduced model has three cumulus parametrizations, referred to as the convergence‐based (CB), boundary layer quasi‐equilibrium (BLQ), and selective boost (SB) options. Regardless of which one is activated, the reduced model produces hurricanes on the same time‐scale as the CSR model. Generally speaking, the hurricanes emerge from turbulence through the coalescence and convective intensification of cyclonic vorticity. Moreover, in both the reduced and CSR models, the onset of ‘rapid intensification’ follows pronounced local growth of theη‐variable of Ooyama (1969), which is a combined measure of deep convective instability and middle tropospheric moisture. Eliminating the surface flux of moist entropyor surface frictionin either model prevents or severely inhibits hurricane formation; however, hurricanes eventually form without surface friction in the BLQ or SB versions of the reduced model.

Despite some measure of success, the reduced model has notable deficiencies that are apparent during the intermediate stage of genesis. Compared to the CSR model, rotational storms are less sporadic and their peak winds are less severe. In the intermediate mesoscale of the reduced model, the horizontal kinetic energy spectrum is relatively steep, and horizontal divergence is relatively weak. Furthermore, the Lagrangian autocorrelation time of vertical vorticity is relatively long. These discrepancies reflect a simplified (quasi‐two‐dimensional) form of rotational convective turbulence. The simplified turbulence has comparatively robust mesoscale vortices, and tends to produce more tropical cyclones than its counterpart generates in the CSR model. Copyright © 2011 Royal Meteorological Society