bluuebunny/crossref_metadata_2025 huggingface dataset:
Relative apparent diffusion coefficient: Determination of reference site and validation of benefit for detecting metastatic lymph nodes in uterine cervical cancer
Authors: Park Sang Ok , Kim Jeong Kon , Kim Kyoung Ah , Park Bum‐Woo , Kim Namkug , Cho Gyunggoo , Choi Hyuk Jae , Cho Kyoung‐Sik
Published: January 2009

Purpose

To determine the reference site for relative apparent diffusion coefficient (rADC) and to evaluate the benefit of rADC for detecting metastatic lymph nodes in uterine cervical cancer.

Materials and Methods

Two observers independently measured ADCs in the spleen, liver, renal cortex, lumbar spine, lumbar spinal cord, and gluteus maximus on diffusion‐weighted images (b value, 0 and 1000 mm/sec2) in 50 patients. The reference site for rADC was determined using the intra‐ and interobserver coefficient of variation (CV) of ADC in these organs. rADC was calculated by ADClesion/ADCreference site. The benefit of rADC over ADC was validated by comparing the area under the receiver operating curve for identifying metastatic lymph nodes in uterine cervical cancer in 130 patients.

Results

The renal cortex was determined to be the reference site for rADC, as its CVs (intraobserver, 5%–7%; interobserver, 5%) were less than those of the other organs (P < 0.05). The ADC and rADC of metastatic lymph nodes (n = 29, ADC, 0.7483 × 10−3 mm2/sec; rADC, 0.3832) were less than those of nonmetastatic lymph nodes (n = 229, ADC, 0.9960 × 10−3 mm2/sec; rADC, 0.5383) (P < 0.05). The area under the receiver operating characteristics curve for differentiating metastatic from nonmetastatic lymph nodes was greater for rADC (0.914; 95% confidence interval [CI], 0.872–0.945) than for ADC (0.872; 95% CI, 0.825–0.910) (P = 0.007).

Conclusion

The renal cortex is an appropriate reference site for rADC and rADC may improve the accuracy for diagnosing metastatic lymph nodes in uterine cervical cancer. J. Magn. Reson. Imaging 2009;29:383–390. © 2009 Wiley‐Liss, Inc.
Comparison of diffusion‐weighted MRI and 2‐[fluorine‐18]‐fluoro‐2‐deoxy‐D‐glucose positron emission tomography (FDG‐PET) for detecting primary colorectal cancer and regional lymph node metastases
Authors: Ono Ken , Ochiai Reiji , Yoshida Tsuyoshi , Kitagawa Mami , Omagari Junichi , Kobayashi Hisashi , Yamashita Yasuyuki
Published: January 2009

Purpose

To examine the usefulness of diffusion‐weighted MRI (DW‐MRI) for the detection of both primary colorectal cancer and regional lymph node metastases, and compare its performance with 2‐[fluorine‐18]‐fluoro‐2‐deoxy‐D‐glucose positron emission tomography (FDG‐PET) in the same patients.

Materials and Methods

We studied 25 patients with known colorectal cancer. All underwent both DW‐MRI and FDG‐PET studies. The images were retrospectively assessed by visual inspection and the imaging findings were compared with histopathological findings on surgical specimens.

Results

Of the 27 primary colorectal lesions surgically excised in 25 patients, 23 (85.2%) were true‐positive on both DW‐MRI and FDG‐PET. Two cancers were false‐negative on DW‐MRI but true‐positive on FDG‐PET, and two were false‐negative on both DW‐MRI and FDG‐PET. With respect to the detectability of metastatic lymph nodes, DW‐MRI and FDG‐PET manifested a sensitivity of 80% (8/10) and 30.0% (3/10), a specificity of 76.9% (10/13) and 100% (13/13), and an accuracy of 78.3% (18/23) and 69.6% (16/23), respectively.

Conclusion

DW‐MRI is inferior to FDG‐PET for the detection of primary lesions, but superior for the detection of lymph node metastases. J. Magn. Reson. Imaging 2009;29:336–340. © 2009 Wiley‐Liss, Inc.
Prediction of locally recurrent prostate cancer after radiation therapy: Incremental value of 3T diffusion‐weighted MRI
Authors: Kim Chan Kyo , Park Byung Kwan , Lee Hyun Moo
Published: January 2009

Purpose

To prospectively evaluate the incremental value of diffusion‐weighted imaging (DWI) with apparent diffusion coefficient (ADC) maps in addition to T2‐weighted imaging (T2WI) for predicting locally recurrent prostate cancer in patients with biochemical failure after radiation therapy.

Materials and Methods

Thirty‐six consecutive patients with an increased prostate‐specific antigen level after radiation therapy underwent 3T MRI followed by transrectal biopsy. The MRI findings and biopsy results were correlated in sextant prostate sectors of peripheral zones (PZs). Two radiologists in consensus reviewed T2WI and combined T2WI and DWI with ADC maps, and rated the likelihood of recurrent cancer on a five‐point scale. ADC values were calculated for recurrent cancer and benign tissue.

Results

Of 216 sectors, 65 prostate sectors (30%) were positive for cancer in 18 patients. For predicting recurrent cancer, combined T2WI and DWI showed a greater sensitivity compared to T2WI (P < 0.001). A significantly greater area under the receiver operating characteristics curve (Az) was determined for combined T2WI and DWI (Az = 0.879, P < 0.01) as compared to T2WI (Az = 0.612). Mean ADC values between recurrent cancer and benign tissue showed a statistically significant difference (P < 0.01).

Conclusion

For predicting locally recurrent prostate cancer after radiation therapy, the use of combined T2WI and DWI showed a better diagnostic performance compared to T2WI. J. Magn. Reson. Imaging 2009;29:391–397. © 2009 Wiley‐Liss, Inc.
Evaluation of measurement uncertainties in human diffusion tensor imaging (DTI)‐derived parameters and optimization of clinical DTI protocols with a wild bootstrap analysis
Authors: Zhu Tong , Liu Xiaoxu , Gaugh Michelle D. , Connelly Patrick R. , Ni Hongyan , Ekholm Sven , Schifitto Giovanni , Zhong Jianhui
Published: January 2009

Purpose

To quantify measurement uncertainties of fractional anisotropy, mean diffusivity, and principal eigenvector orientations in human diffusion tensor imaging (DTI) data acquired with common clinical protocols using a wild bootstrap analysis, and to establish optimal scan protocols for clinical DTI acquisitions.

Materials and Methods

A group of 13 healthy volunteers were scanned using three commonly used DTI protocols with similar total scan times. Two important parameters—the number of unique diffusion gradient directions (NUDG) and the ratio of the total number of diffusion‐weighted (DW) images to the total number of non‐DW images (DTIR)—were analyzed in order to investigate their combined effects on uncertainties of DTI‐derived parameters, using results from both the Monte Carlo simulation and the wild bootstrap analysis of uncertainties in human DTI data.

Results

The wild bootstrap analysis showed that uncertainties in human DTI data are significantly affected by both NUDG and DTIR in many brain regions. These results agree with previous predictions based on error‐propagations as well as results from simulations.

Conclusion

Our results demonstrate that within a clinically feasible DTI scan time of about 10 minutes, a protocol with number of diffusion gradient directions close to 30 provides nearly optimal measurement results when combined with a ratio of the total number of DW images over non‐DW images equal to six. Wild bootstrap can serve as a useful tool to quantify the measurement uncertainty from human DTI data. J. Magn. Reson. Imaging 2009;29:422–435. © 2009 Wiley‐Liss, Inc.
Interleaved T1 and T2 relaxation time mapping for cardiac applications
Authors: Blume Ulrike , Lockie Timothy , Stehning Christian , Sinclair Stephen , Uribe Sergio , Razavi Reza , Schaeffter Tobias
Published: January 2009

Purpose

To diagnose acute myocardial infarction (MI) with MRI, T1‐weighted and T2‐weighted images are required to detect necrosis and edema. The calculation of both T1 and T2 maps can be relevant for quantitative diagnosis. In this work, we present a simultaneous quantification of T1‐T2 relaxation times of a short‐axis view of the heart in a single scan.

Materials and Methods

An electrocardiograph (ECG)‐triggered, navigator‐gated, interleaved T1 and T2 mapping sequence was implemented for the quantification of the T1 and T2 values of phantoms, healthy volunteers, and three patients with acute MI. The proposed acquisition scheme consisted of an interleaved two‐dimensional (2D) steady‐state free precession (SSFP) sequence with three different modules: an inversion‐recovery (IR) sequence with multiple time delays, followed by a delay of one cardiac cycle for magnetization recovery and a T2‐preparation pulse with multiple echo‐times for T2 quantification.

Results

Measurements of in vivo relaxation times were in good agreement with literature values. The interleaved sequence was able to measure T1 and T2 relaxation times of the myocardium.

Conclusion

The interleaved sequence acquires data for the calculation of T1 and T2 maps in only one scan without the need for registration. This technique has the potential to differentiate between acute and chronic MI by estimating the concentration of gadolinium diethylenetriamine pentaacetic acid (Gd‐DTPA) in the necrotic tissue and to assess the extent of edema from T2 maps. J. Magn. Reson. Imaging 2009;29:480–487. © 2009 Wiley‐Liss, Inc.
Contiguous‐slice zonally oblique multislice (CO‐ZOOM) diffusion tensor imaging: Examples of in vivo spinal cord and optic nerve applications
Authors: Dowell Nicholas G. , Jenkins Thomas M. , Ciccarelli Olga , Miller David H. , Wheeler‐Kingshott Claudia A.M.
Published: January 2009

Purpose

To describe and demonstrate a new technique that allows diffusion tensor imaging of small structures such as the spinal cord (SC) and optic nerve (ON) with contiguous slices and reduced image distortions using a narrow field of view (FOV).

Materials and Methods

Images were acquired with a modified single‐shot echo‐planar imaging (EPI) sequence that contains a refocusing radio frequency (RF) pulse in the presence of the phase‐encoding (rather than slice‐select) gradient. As a result, only a narrow volume may be both excited and refocused, removing the problem of signal aliasing for narrow FOVs. Two variants of this technique were developed: cardiac gating is included in the study of the SC to reduce pulsation artifacts, whereas inversion‐recovery (IR) cerebrospinal fluid (CSF) suppression is utilized in the study of the ON to eliminate partial volume effects. The technique was evaluated with phantoms, and mean diffusivity (MD) and fractional anisotropy (FA) measurements were made in the SC and ON of two healthy volunteers.

Results

The technique provides contiguous‐slice, reduced‐FOV images that do not suffer from aliasing and have reduced magnetic susceptibility artifacts. MD and FA values determined here lie within the ranges quoted in the literature.

Conclusion

Contiguous‐slice zonally orthogonal multislice (CO‐ZOOM‐EPI is a new technique for diffusion‐weighted imaging of small structures such as the ON and SC with high resolution and reduced distortions due to susceptibility variations. This technique is able to acquire contiguous slices that may allow further nerve‐tracking analyses. J. Magn. Reson. Imaging 2009;29:454–460. © 2009 Wiley‐Liss, Inc.
T2 detection of tumor invasion within segmented components of glioblastoma multiforme
Authors: McMillan Kathryn M. , Ehtesham Moneeb , Stevenson Charles B. , Edgeworth Michael L. , Thompson Reid C. , Price Ronald R.
Published: January 2009

Purpose

To use T2‐weighted images to detect tumor invasion when comparing normal individuals to groups of gliomablastoma multiforme (GBM) patients with varying levels of CXCR4, a chemokine receptor that promotes tumor migration.

Materials and Methods

T2‐weighted images were acquired preoperatively in 22 treatment‐naïve GBM patients. Two groups were formed based on the expression levels of CXCR4. A third group of normal volunteers was used for comparison. Each image was segmented to obtain four different clusters for tissue types identified as white matter, basal ganglia, gray matter/edema and cerebrospinal fluid (CSF)/tumor. Signal intensity histograms were formed for each cluster and compared between groups.

Results

In every cluster the GBM groups displayed significantly higher standard deviations of intensity distributions when compared to normal subjects. Significant differences in skewness were found between normal subjects and GBM patients in the white matter, basal ganglia, and CSF/tumor. Further, when the two groups of GBM patients were compared the CXCR4‐high group was found to have a significant shift in the median intensity values in the cluster containing gray matter and peritumoral edema.

Conclusion

T2 signal intensity histograms in normal subjects differ significantly from those obtained from GBM groups, suggesting widespread dissemination of disease. J. Magn. Reson. Imaging 2009;29:251–257. © 2009 Wiley‐Liss, Inc.
Spleen R2 and R2* in iron‐overloaded patients with sickle cell disease and thalassemia major
Authors: Brewer Casey J. , Coates Thomas D. , Wood John C.
Published: January 2009

Purpose

To evaluate the magnetic properties of the spleen in chronically transfused, iron‐overloaded patients with sickle cell disease (SCD) and thalassemia major (TM) and to compare splenic iron burdens to those in the liver, heart, pancreas, and kidneys.

Materials and Methods

A retrospective analysis of 63 TM and 46 SCD patients was performed. Spleen R2 and R2* values were calculated from spin‐echo and gradient‐echo images collected between April 2004 and September 2007.

Results

The spleen showed a different R2–R2* relationship than that previously established for the liver. At high iron concentrations (R2* > 300 Hz), spleen R2 was lower than predicted for liver. The proportion of splenic to hepatic iron content was greater in SCD patients compared with TM patients (23.8% vs. 13.8%). A weak association was found between splenic and liver iron—this association was stronger in SCD patients. Little correlation was found between splenic iron and extrahepatic R2* values.

Conclusion

For spleen and liver tissue with the same R2* value, splenic R2 was significantly lower than hepatic R2, particularly for R2* > ≈300 Hz. Splenic iron levels have little predictive value for R2* values of heart, pancreas, and kidney. J. Magn. Reson. Imaging 2009;29:357–364. © 2009 Wiley‐Liss, Inc.
Evaluation of the translational and rotational forces acting on a highly ferromagnetic orthopedic spinal implant in magnetic resonance imaging
Authors: McComb Christie , Allan David , Condon Barrie
Published: January 2009

Purpose

To assess the translational and rotational forces acting on a highly ferromagnetic orthopedic spinal implant in 1.5T and 3.0T magnetic resonance (MR) systems.

Materials and Methods

The translational forces and rotational forces, or torques, acting on the implant were measured using existing methods and assessed using the guidelines produced by the American Society for Testing and Materials (ASTM).

Results

The measured translational forces were many times greater than for any other orthopedic implant previously recorded in the literature and, based on deflection angle criteria, would be considered unsafe in both MR systems. However, due to the rigid fixation of orthopedic implants in bone, implant migration is considered highly unlikely. Several constituent components of the implant were subjected to large torques, in some cases an order of magnitude greater than the corresponding torque due to gravity. However, the counterbalancing effect of the configuration of the combined implant results in a net torque that is less than the torque due to gravity.

Conclusion

The translational and rotational forces acting on the implant in both 1.5T and 3.0T MR systems are substantial, but based on theoretical considerations are unlikely to result in implant migration or rotation. J. Magn. Reson. Imaging 2009;29:449–453. © 2009 Wiley‐Liss, Inc.
Age dependence of T1 perfusion MRI‐based hemodynamic parameters in human kidneys
Authors: Dujardin Martine , Luypaert Rob , Sourbron Steven , Verbeelen Dierik , Stadnik Tadeusz , de Mey Johan
Published: January 2009

Purpose

To determine the association between renal cortical perfusion parameters from T1‐DCE magnetic resonance imaging (MRI) and age in human kidney.

Materials and Methods

Thirty‐five patients (mean age: 53 years, SD = 15 years) were imaged using inversion recovery (IR)‐prepared FLASH (pulse repitition time [TR] = 4.4 msec, echo time [TE] 2.2 msec, inversion time [TI] = 180 msec, FA 50°, matrix 128 × 256, 0.3 sec/slice) during the injection of Gadolinium‐DTPA. Tissue concentration–time courses were deconvolved. Renal blood flow (RBF), volume of distribution (RVD), and mean transit time (MTT) were derived from the resulting impulse response function.

Results

Mean RBF, RVD, and MTT were 127 mL/min/100 mL (SD = 81 mL/min/100 mL), 40 mL/100 mL (SD 23 mL/100 mL), and 22 sec (SD = 9 sec). A significant moderately negative correlation was found between RBF and age (R= −0.447,P= 0.007), RVD and age (R= −0.420,P= 0.012). MTT and age did not show a significant correlation (R= 0.017,P= 0.924). Repeating this analysis for each gender revealed a moderate age dependence of RBF (R= −0.600 withP= 0.009) and RVD (R= −0.540 withP= 0.021) in the male group only.

Conclusion

T1‐DCE quantitative perfusion MRI was sufficiently sensitive to demonstrate a significant negative correlation of RBF and RVD with patient age. This was due to a moderate age dependence of these quantities in males that seems to be absent in females. J. Magn. Reson. Imaging 2009;29:398–403. © 2009 Wiley‐Liss, Inc.
No efficacy of silver bone cement in the prevention of methicillin‐sensitiveStaphylococcalinfections in a rabbit contaminated implant bed model
Authors: Moojen Dirk Jan F. , Vogely H. Charles , Fleer André , Verbout Abraham J. , Castelein René M. , Dhert Wouter J.A.
Published: January 2009

Data from literature showed that a new type of metallic silver PMMA cement had good results in infection prophylaxis. This study investigated the in vivo efficacy of silver cement in the prevention of methicillin‐sensitiveStaphylococcalinfections, compared to plain and tobramycin‐containing cement. In 48 rabbits, 0.6% silver, 1% silver, plain, or tobramycin PMMA cement was injected into the femoral medullary canal after contamination with 105, 106, or 107colony forming units (CFU)Staphylococcus aureus. After 14 days, bone was collected for bacteriology and histopathology. All plain and silver cement rabbits were infected, whereas only two tobra rabbits were infected (p < 0.001). The number of bacteria cultured (10logCFU) from bone adjacent to the cement, was 6.4 ± 0.3 and 6.1 ± 0.3 for the 0.6% and 1% silver rabbits. For the rabbits with plain and tobra cement, this was 6.2 ± 0.2 (p > 0.95) and 0.0 ± 0.0 (p < 0.001), respectively. Two tobra rabbits had a positive culture of a distal bone sample. Histological sections of plain, 0.6%, and 1% silver rabbits all showed signs of infection; these signs were absent in the tobra rabbits. Silver and plain cement were not effective in preventing infection, whereas tobra cement was effective. As silver cement predominantly exhibits an antimicrobial effect at the direct cement surface, this cement seems less useful in situations where there are bacteria present in surrounding tissues, like revision surgery. Whether silver cement has relevance in the prevention of bacterial colonization of cement remains to be determined. © 2009 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 27: 1002–1007, 2009
Purification of flavonoids and triterpene saponins from the licorice extract using preparative HPLC under RP and HILIC mode
Authors: Zhang Hui , Guo Zhimou , Li Wei , Feng Jiatao , Xiao Yuansheng , Zhang Feifang , Xue Xingya , Liang Xinmiao
Published: January 2009

A four‐channel preparative HPLC was employed to isolate and purify compounds from licorice extract. Two separation modes, RP and hydrophilic interaction LC (HILIC), were used in preparative HPLC. HILIC mode was adopted to resolve the purification of the compounds with similar hydrophobicity, which were co‐eluted under RP mode. Using the two separation modes during the purification process, fifteen compounds were isolated from licorice extract. The results indicated that preparative HPLC performed under HILIC mode is an efficient method for the isolation and purification of compounds from natural products.
The Surface Modification of Hydroxyapatite Nanoparticles by the Ring Opening Polymerization of γ‐Benzyl‐L‐glutamate N‐carboxyanhydride
Authors: Wei Junchao , Liu Aixue , Chen Lei , Zhang Peibiao , Chen Xuesi , Jing Xiabin
Published: January 2009

The surface modification of hydroxyapatite (HA) nanoparticles by the ring opening polymerization (ROP) of γ‐benzyl‐L‐glutamate N‐carboxyanhydride (BLG‐NCA) was proposed to prepare the poly(γ‐benzyl‐L‐glutamate) (PBLG)‐grafted HA nanoparticles (PBLG‐g‐HA) for the first time. HA nanoparticles were firstly treated by 3‐aminopropylthriethoxysilane (APS) and then the terminal amino groups of the modified HA particles initiated the ROP of BLG‐NCA to obtain PBLG‐g‐HA. The process was monitored by XPS and FT‐IR. The surface grafting amounts of PBLG on HA ranging from 12.1 to 43.1% were characterized by thermal gravimetric analysis (TGA). The powder X‐ray diffraction (XRD) analysis confirmed that the ROP only underwent on the surface of HA nanoparticles without changing its bulk properties. The SEM measurement showed that the PBLG‐g‐HA hybrid could form an interpenetrating net structure in the self‐assembly process. The PBLG‐g‐HA hybrid could maintain higher colloid stability than the pure HA nanoparticles. The in vitro cell cultures suggested the cell adhesion ability of PBLG‐g‐HA was much higher than that of pure HA.

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Poly(N‐hydroxyethylacrylamide) Prepared by Atom Transfer Radical Polymerization as a Nonionic, Water‐Soluble, and Hydrolysis‐Resistant Polymer and/or Segment of Block Copolymer with a Well‐Defined Molecular Weight
Authors: Narumi Atsushi , Chen Yougen , Sone Masako , Fuchise Keita , Sakai Ryosuke , Satoh Toshifumi , Duan Qian , Kawaguchi Seigou , Kakuchi Toyoji
Published: January 2009

N‐Hydroxyethylacrylamide (HEAA) was polymerized using the atom transfer radical polymerization (ATRP) with ethyl 2‐chloropropionate (ECP), copper(I) chloride (CuCl), and tris[2‐(dimethylamino)ethyl]amine (Me6TREN) in ethanol/water, producing poly(N‐hydroxyethylacrylamide) (PHEAA) with well‐defined molecular weights. The thermogravimetric analysis (TGA) indicated that the obtained PHEAA broadly decomposed with a two‐stage weight loss. The first loss was due to the decomposition of the hydroxyethyl groups, which started at temperatures ranging from 249.2 to 277.1 °C. The remaining polyacrylamide backbones started to decompose at temperatures ranging from 352.5 to 383.4 °C. The differential scanning calorimetry (DSC) indicated that PHEAA had a glass transition temperature (Tg) ranging from 70.6 to 117.8 °C. The ability of the obtained PHEAA as a prepolymer to initiate other acrylamide derivatives is described. N,N‐Dimethylacrylamide (DMAA), N‐acyloylmorpholine (NAM), and N‐[3‐(dimethylamino)propyl]acrylamide (DMAPAA) were subsequently added to the solutions after the polymerization of HEAA with ECP/CuCl/Me6TREN, producing the corresponding block copolymers.

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Droplet Tailoring Using Evaporative Inkjet Printing
Authors: Perelaer Jolke , Smith Patrick J. , Wijnen Mike M. P. , van den Bosch Erwin , Eckardt Rebecca , Ketelaars Peter H. J. M. , Schubert Ulrich S.
Published: January 2009

An experimental study into the in‐flight evaporation and impact of equally sized inkjet printed droplets that consist of a systematically varied polystyrene concentration in either toluene or butyl acetate is presented. At low polymer concentrations, a linear relationship that decreased was observed between dried droplet diameter and printing height. However, increased concentrations revealed an initial exponential decay in the dried droplet diameter, which stabilized at greater heights. At higher concentration and height, the polymer forms a skin on the surface of the inkjet printed droplet, which causes inhibition of the in‐flight evaporation of the solvent.

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Thiyl Radical Generation in Thiol or Disulfide Containing Photosensitive Systems
Authors: Lalevée Jacques , Morlet‐Savary Fabrice , Roz Mohamad El , Allonas Xavier , Fouassier Jean Pierre
Published: January 2009

The generation of thiyl radicals in various multicomponent photosensitive systems based on a ketone, a coumarin or a ketocoumarin and containing a thiol or a disulfide and eventually chloro bis‐imidazole has been studied through laser flash photolysis. A set of more than 70 new interaction rate constants is provided. The measurements of the quantum yields in sulfur radicals and the rate constants of the different processes in many combinations as well as the molecular orbital calculations allow to discuss the driving factors of the involved reactions. This approach should shed some light on the possible explanations of the high performance of some of these combinations when used as photoinitiating systems for radical photopolymerization reactions.

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Macromol. Rapid Commun. 3/2009
Authors: Feng Fude , Duan Xinrui , Wang Shu
Published: January 2009

Cover: The image shows a platform for DNA lesion detection that interfaces a single nucleotide base extension reaction with the signal amplification property of conjugated polymers. This new protocol offers a convenient detection for DNA lesions in aqueous solution without any isolation and wash steps. Further details can be found in the article by F. Feng, X. Duan, and S. Wang* on page 147.
Silibinin protects OTA‐mediated TNF‐α release from perfused rat livers and isolated rat Kupffer cells
Authors: Al‐Anati Lauy , Essid Ebtisam , Reinehr Roland , Petzinger Ernst
Published: January 2009

We studied the inhibitory effect of silibinin on ochratoxin A (OTA) and LPS‐mediated tumor necrosis factor α (TNF‐α) release and the leakage of cytotoxic markers glutamate dehydrogenase (GLDH) and lactate dehydrogenase (LDH), from isolated blood‐free perfused rat livers, and from isolated pure rat Kupffer cells. In the recirculation perfusion model at the end point 90 min, 2.5 μmol/L OTA released 2600 pg/mL TNF‐α without effects on liver vitality. LPS at 0.1 μg/mL induced 3000 pg TNF‐α/mL with slight leakage of GLDH and LDH. Under similar experimental conditions, the addition of silibinin 10 min prior to OTA and LPS showed dose‐dependent protection against OTA or LPS‐induced hepatic TNF‐α release. High‐dose of silibinin (12.5 μg/mL) also completely restored GLDH and LDH levels in the perfusate. Pretreatment of isolated Kupffer cells with 0.02, 0.1, 0.5, 2.5, and 12.5 μg silibinin/mL 30 min prior to OTA reduced OTA‐induced TNF‐α levels to 90, 70, 25, 25, and 25% at 4 h, respectively, and abrogated any TNF‐α release at 24 h. Similarly, in the presence of silibinin LPS‐induced TNF‐α levels decreased at 4 h to 71, 57, 18, 22, and 18%, respectively. However, after 24 h of LPS exposition the protection by silibinin vanished and TNF‐α partially recurred into the incubation medium under LPS. In summary, silibinin had hepatoprotective effects against OTA‐ or LPS‐mediated TNF‐α release and also reduced the cytotoxicity of both toxins. Isolated Kupffer cells were even more sensitive to the protective effect than perfused livers and responded to very low concentrations of silibinin with a strong inhibition of toxins‐mediated TNF‐α release.
1.25‐Gb/s wireline and wireless data transmission in wavelength reusing WDM passive optical networks
Authors: Won Yong‐Yuk , Kwon Hyuk‐Choon , Hong Moon‐Ki , Han Sang‐Kook
Published: January 2009

A new architecture for a wavelength‐reused wavelength division multiplexed‐passive optical network, which is simultaneously transmitting both a wireline data and a wireless one, is proposed and demonstrated experimentally. The proposed scheme uses a Mach–Zehnder modulator in the central office and a reflective semiconductor optical amplifier in the optical network unit. The subcarrier multiplexing method is utilized to simultaneously generate a wireline data and a wireless one for a downlink transmission. A downlink light is reused to transmit an uplink data using a reflective semiconductor optical amplifier. A transmitted downlink data is suppressed due to the gain saturation effect of a reflective semiconductor optical amplifier in the optical network unit and it is possible to directly remodulate an uplink 1.25‐Gb/s baseband data. A 1.25‐Gb/s bidirectional error free transmission is accomplished after 20‐km optical transmission. © 2009 Wiley Periodicals, Inc. Microwave Opt Technol Lett 51: 627–629, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24118
Flat‐plate pentagonal monopole antenna for laptop wireless communication and mobile TV reception
Authors: Pazin Lev , Leviatan Yehuda
Published: January 2009

An improved novel printed wideband flat‐plate monopole antenna is presented. The proposed antenna consists of a pentagonal monopole embedded in a corner notch in the antenna ground plane part. Simulated and measured results of the input return loss for the proposed antenna are in good agreement. The antenna has been shown to operate satisfactorily in the 0.47–6 GHz frequency range, and is therefore very suitable for use as antenna for laptop applications including Wi‐Fi, WiMAX, and mobile TV reception. © 2009 Wiley Periodicals, Inc. Microwave Opt Technol Lett 51: 612–615, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24133
Low‐profile resonant cavity antenna based on an in‐phase metamaterial surface
Authors: Ge Yuehe , Esselle Karu P.
Published: January 2009

A partially reflective metamaterial surface is designed to have in‐phase reflection property for the purpose of reducing the height of resonant cavity antennas. Since the reflection phase of the in‐phase is close to 0° at the operating band, the cavity height, that is, the distance between the metamaterial surface and the PEC ground, can be reduced from half wavelength to about a quarter wavelength, without using an artificial magnetic conductor as the ground. An example antenna is designed, fabricated, and measured to demonstrate the concept. © 2009 Wiley Periodicals, Inc. Microwave Opt Technol Lett 51: 731–733, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24134
New microstrip low pass filter with transmission zero and wide stopband
Authors: Xiao Jian‐Kang , Chu Q.‐X. , Huang H.‐F.
Published: January 2009

New microstrip low pass filters with low insertion loss, ultra‐wide stopband and transmission zero are presented by using triangular patch resonator with fractal defection. With such defection and a certain parallel feed method, undesired responses and harmonics are effectively suppressed and wideband, sharp attenuation obtained. The new filter has simpler and more compact configurations even better filter properties than the traditional line based ones. © 2009 Wiley Periodicals, Inc. Microwave Opt Technol Lett 51: 830–831, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24138
Characterization of the polarization in the spun fibers
Authors: Cherbi L. , Azrar A. , Mehenni M. , Aksas R.
Published: January 2009

The polarization mode dispersion (PMD) is a difficult phenomenon to compensate in the optical fiber. Its reduction can be achieved by the spinning process that provokes the rotation of the birefringence axes of the fiber inciting a coupling of its modes that is controlled at the time of its manufacture. In this work, the Jones Matrix Eigen‐Analysis method (JME) is used to characterize the spun fibers to evaluate their PMD and to prove that it is distinctly lower than the standards fibers PMD. Furthermore, the differential group delays (DGD) of spun fibers is determined using the photon counting optical time‐domain reflectometry (C‐OTDR) method. The obtained results are compared with those found in the JME method. It is noted that the two methods yield practically identical values. The determination of the beat length and the spin period of spun fibers is carried out using the polarization‐sensitive optical frequency‐domain reflectometer (POFDR). © 2009 Wiley Periodicals, Inc. Microwave Opt Technol Lett 51: 725–731, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24143
Fast modeling using FDTD method and wave front inverse method for multisensor GPR simulations in the time domain
Authors: Neyrat Mathieu , Guiffaut Christophe , Reineix Alain , Reynaud François
Published: January 2009

This article deals with a fast numerical method for GPR simulation of great scenes. Electromagnetic wave propagation in heterogeneous media is analyzed using a finite‐difference time‐domain (FDTD)‐based method. The use of a moving subdomain allows dealing with large scale and realistic B‐scan or C‐scan in a reasonable computational time. A simple and fast inversion method based on a coherent superposition of signal phases will also be exposed. The performances of this method for the localization and shape recovering of various buried objects will be pointed out. This process is very easy to implement and also has the advantage to be used for monostatic or multisensor radar records. © 2009 Wiley Periodicals, Inc. Microwave Opt Technol Lett 51: 796–802, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24153
Linearity‐optimized class‐E Doherty amplifier based on GaN HEMT
Authors: Lee Yong‐Sub , Lee Mun‐Woo , Jeong Yoon‐Ha
Published: January 2009

In this article, we report the linearity improvement of the GaN HEMT class‐E Doherty power amplifier (CEDA). For the linearity improvement, not only the gate biases but also the matching circuits of the carrier and peaking cells are optimally controlled at a pout of 38 dBm, which is a 7‐dB back‐off power. For a two‐tone signal with 1‐MHz tone spacing, the IMD3 of‐58 dBc is achieved with a power‐added efficiency (PAE) of 45.4%. For a one‐carrier WCDMA signal, the PAE of 46.7% is obtained with an ACLR of‐32.9 dBc. © 2009 Wiley Periodicals, Inc. Microwave Opt Technol Lett 51: 763–766, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24154
Investigation on the use of high‐permittivity substrate in stacked patch antenna fed by a coplanar waveguide
Authors: Chen Yih‐Chien , Tsai Jian‐Min
Published: January 2009

In this article, the measurement results for the use of high‐permittivity material in stacked patch antenna, with coplanar waveguide feed line at 2.5 GHz, have been presented. With this technique, a 13% bandwidth (return loss < −10 dB) of center frequency at 2.5 GHz has been successfully achieved. The copolarization radiation is strongest at θ ≅ 0° from the broadside both in the xz‐ and yz‐ planes. The antenna has a 3 dB beam angle of about 110° and 85° in the xz‐ and yz‐ planes, respectively. Peak antenna gain is about 4.9 dBi, and the gain is >2.0 dBi for frequencies within in the −10 dB S11bandwidth. © 2009 Wiley Periodicals, Inc. Microwave Opt Technol Lett 51: 715–717, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24157
Fractal‐shaped microstrip dual‐mode bandpass filter with asymmetrical sinuous spurlines
Authors: Tong Fu , Liu Haiwen
Published: January 2009

In this article, miniaturized dual‐mode bandpass filters using Koch fractal‐shaped slots and sinuous spurlines are proposed. Because of the space‐filling property of the fractal geometry, the transmission characteristics of this filter can be adjusted by the iteration order of the Koch fractal curve. Moreover, asymmetrical sinuous spurlines are adopted to tune the degenerate modes. Compared with the conventional square‐patch filters, fractal slots and sinuous spurlines can also provide more current distribution distortions which improve the electrical length and realize a compact design. Experimental data in agreement with theoretical data verify the design methodology. © 2009 Wiley Periodicals, Inc. Microwave Opt Technol Lett 51: 745–747, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24167
A quasi‐elliptic wideband bandpass filter using a novel multiple‐mode resonator constructed by an asymmetric compact microstrip resonant cell
Authors: Li Lin , Li Zheng‐Fan , Wei Qi‐Fu
Published: January 2009

This article proposes a novel wideband bandpass filter using a novel microstrip multiple‐mode resonator (MMR). This MMR is composed of a section of open‐ended microstrip‐line and an asymmetric compact microstrip resonant cell (ACMRC) connected to the open‐ended microstrip‐line section at its central point. Its three resonant modes are employed in this article to construct the wider passband of the proposed filter. In addition, multiple transmission zeros brought by the ACMRC will help to create a quasi‐elliptic response and extend the stopband. Finally, a demonstration filter is designed, fabricated and tested to show the validity of the proposed structure. Both simulated and measured results show that the proposed filter has a good performance. © 2009 Wiley Periodicals, Inc. Microwave Opt Technol Lett 51: 713–714, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24168
Overall size antenna reduction using fractal elements
Authors: de Oliveira E. E. C. , da F. Silva P. H. , Campos A. L. P. S. , da Silva Sandro Gonçalves
Published: January 2009

This article presents a proposal for microstrip patch antennas miniaturization using Koch curve fractal contours. The antennas were designed using the Ansoft DesignTMsoftware and several prototypes were built. All the build antennas obtained return loss lower than −30 dB at the resonant frequencies. The use of inset‐fed technique effectively allows an excellent impedance matching of the fractal antennas using a recessed microstrip‐line feed. With the use of appropriated fractal iteration factors, the proposed Koch fractal patch antennas are 39% smaller in size than a conventional rectangular inset‐fed patch. © 2009 Wiley Periodicals, Inc. Microwave Opt Technol Lett 51: 671–675, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24171
Fully embedded lumped LC‐quadrature hybrid coupler into organic packaging substrate for power sampling
Authors: Lee Yi Jae , Park Jae Yeong
Published: January 2009

In this article, fully embedded lumped LC‐quadrature hybrid coupler are designed, fabricated, and characterized into multilayered organic packaging substrate. This embedded device comprised high Q MIM capacitors and circular spiral stacked inductors. For realizing fully embedded high Q capacitor, barium titanate (BaTiO3) composite high dielectric film was utilized. The measured return loss and isolation were better than 25 dB. Measured insertion loss was about 0.38–0.42 dB at the frequencies ranged from 824 to 894 MHz. The coupler exhibited a coupling loss of 23.3–24 dB. The phase error between through and coupling ports was 1.2°–2.4°. It has a size of 2.8 mm ×2.95 mm ×0.77 mm (height), which is the smallest one in the couplers developed onto the packaging substrate. The measured performance characteristics were also well matched with the 3D EM simulated ones. © 2009 Wiley Periodicals, Inc. Microwave Opt Technol Lett 51: 845–848, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24173
Electromagnetic wave absorption by H2O‐filled SiO2 shell microcapsule‐dispersed paraffin matrix composites
Authors: Matsumura K. , Kagawa Y.
Published: January 2009

Electromagnetic wave absorption of H2O‐filled SiO2 shell microcapsule‐dispersed paraffin matrix composites has been examined in a frequency range from 18 to 30 GHz. The composites showed electromagnetic wave absorption potential, and the electromagnetic wave absorption can be controlled by a volume fraction of liquid state H2O in the composite. © 2009 Wiley Periodicals, Inc. Microwave Opt Technol Lett 51: 770–772, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24175
A printed multiband antenna for cellphone applications
Authors: Sun Shih‐Ying , Huang Sheng‐Yi , Sun Jwo‐Shiun
Published: January 2009

A printed antenna is presented, which is working in bluetooth band of 2.4 GHz, worldwide interoperability for microwave access IEEE 802.16e band of 3.5 GHz and 5.8 GHz, wireless fidelity band of 2.4–2.5 GHz and 5.0–5.8 GHz, and wireless local area network band of 2.4–2.48 GHz, 5.15–5.35 GHz, and 5.72–5.83 GHz. The ratios of impedance bandwidth of the printed antenna to the central frequencies 3.5 GHz and 5.5 GHz are 54.5% and 15.5%, respectively. The total volume of the printed antenna is 20 (L) × 7.6 (W) × 0.4 (H) mm3, which is greatly reduced by 36% compared to generally internal printed antennas. The good characteristics of the printed antenna such as omnidirectional far‐field patterns are attainable. The experimental results show agreement with the simulated data by high frequency structure simulator. © 2009 Wiley Periodicals, Inc. Microwave Opt Technol Lett 51: 742–744, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24177
A compacted CMOS K‐band bandpass filter using meandering thin film microstrip and UC‐PBG structures
Authors: Lin Shuiyang , Yang Liwu , Sun Xiaowei
Published: January 2009

A compacted CMOS K‐band bandpass filter incorporating meandering thin film microstrip and defective uniplanar compact photonic bandgap (UC‐PBG) slow‐wave structures for size reduction are presented. Benefited from the multilayer metal technology of the standard 0.18‐μm CMOS process, meandering thin film microstrip and broadside‐coupled structures with large coupling degree are properly constructed to realize bandpass filters with small insertion loss. The slow‐wave effect of UC‐PBG structure is investigated and a center frequency drop of 14% is achieved by the use of UC‐PBG ground. A 3.6‐dB loss 18‐GHz filter with two transmission poles has been designed and implemented in standard 0.18‐μm CMOS technology and only with an area of 0.34 mm2. © 2009 Wiley Periodicals, Inc. Microwave Opt Technol Lett 51: 871–874, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24180
A finite element approach for finding positive solutions of semilinear elliptic Dirichlet problems
Authors: Kumar Manoj , Kumar Prashant
Published: January 2009

In the present article, we described the finite element method for finding positive solutions for the elliptic problems of the type ‐ Δu = λf(x)g(u) for x ε Ω, with Dirichlet boundary condition. By using Matlab, we visualize the range of λ in which this problem achieves a numerical solution, and also discussed the behavior of the branch of this solution. © 2009 Wiley Periodicals, Inc. Numer Methods Partial Differential Eq, 2009
A compact finite difference method for the solution of the generalized Burgers–Fisher equation
Authors: Sari Murat , Gürarslan Gürhan , Dağ İdris
Published: January 2009

In this article, numerical solutions of the generalized Burgers–Fisher equation are obtained using a compact finite difference method with minimal computational effort. To verify this, a combination of a sixth‐order compact finite difference scheme in space and a low‐storage third‐order total variation diminishing Runge–Kutta scheme in time have been used. The computed results with the use of this technique have been compared with the exact solution to show the accuracy of it. The approximate solutions to the equation have been computed without transforming the equation and without using linearization. Comparisons indicate that there is a very good agreement between the numerical solutions and the exact solutions in terms of accuracy. The present method is seen to be a very good alternative to some existing techniques for realistic problems. © 2009 Wiley Periodicals, Inc. Numer Methods Partial Differential Eq, 2010
Development of the hospital nurse surveillance capacity profile
Authors: Kutney‐Lee Ann , Lake Eileen T. , Aiken Linda H.
Published: January 2009

Better patient outcomes are often achieved through effective surveillance, a primary function of nurses. The purpose of this article is to define, operationalize, measure, and evaluate the nurse surveillance capacity of hospitals. Nurse surveillance capacity is defined as the organizational features that enhance or weaken nurse surveillance. It includes a set of registered nurse (staffing, education, expertise, experience) and nurse practice environment characteristics. Empirical referents were extracted from existing survey data from 9,232 nurses in 174 hospitals. Using a ranking methodology, a Hospital Nurse Surveillance Capacity Profile was created for each hospital. Greater nurse surveillance capacity was significantly associated with better quality of care and fewer adverse events. The profile may assist administrators to improve nurse surveillance and patient outcomes. © 2009 Wiley Periodicals, Inc. Res Nurs Health 32:217–228, 2009
Politics over markets: Integrating state‐owned enterprises into Chinese socialist market
Authors: Chan Hon S.
Published: January 2009

Interest is growing in the reform of China's state‐owned enterprises (SOEs), both within and outside China. Many studies argue that the highest‐ranking mainland enterprises on lists of top global enterprises and national 100‐strongest companies are indicative of their successful integration into world and local markets. However, despite their high ranking, the strength of their performance is in doubt. In the socialist market situation of China, key business sectors continue to be dominated by the public sector, and SOEs control the commanding heights of the national economy. The urge for more market‐oriented changes aside, China's SOEs are still required to pursue and fulfil both commercial and non‐commercial interests and obligations. This article finds that SOE reform is more a reflection of local economic nationalism. Economic nationalism is the driving force behind the SOE reforms, with public administration and state economic management at the forefront and free market development as only secondary interest. Copyright © 2009 John Wiley & Sons, Ltd.
Governing by goals and numbers: A case study in the use of performance measurement to build state capacity in China
Authors: Gao Jie
Published: January 2009

This article examines why performance measurement, a tool adopted by western countries chiefly to improve government services, has been designed and implemented as an instrument for building state capacity and for ensuring policy compliance in China. Under China's performance measurement system, the central government translates its macro reform goals into specific policy objectives, which it then assigns downwards through the administrative hierarchy. Local governments at the county level convert the policy objectives allocated to them into a variety of prioritised performance targets for local officials to achieve. Using the experience of an inland Chinese county as a case study, this article argues that performance measurement accrues significant political benefits to its users. It forces local Chinese officials to concentrate their efforts on realising the policy priorities set by the higher‐level authorities. However, the way that performance measurement is conducted—governing by goals and numbers—does not address the substantial governance issues and fundamental social and political tensions that exist in Chinese society. Copyright © 2009 John Wiley & Sons, Ltd.