bluuebunny/crossref_metadata_2025 huggingface dataset:
Twin gestation in one horn of a bicornuate uterus
Authors: Narlawar Ranjeet S. , Chavhan Govind B. , Bhatgadde Veena L. , Shah Jeshil R.
Published: February 2003

We report a rare case of twin pregnancy in the same horn of a bicornuate uterus. This patient's uterine malformation was detected for the first time when she experienced abdominal pain at 6 weeks of amenorrhea. Transabdominal and transvaginal sonographic examinations were performed. Both embryos showed cardiac motion on transvaginal sonography. The patient was re‐examined monthly. Her pregnancy ended in spontaneous abortion at 22 weeks. Two live male fetuses were delivered, but they both died immediately after their birth. Sonography, particularly transvaginal sonography, is valuable for early detection of uterine abnormalities that may affect the outcome of pregnancy. © 2003 Wiley Periodicals, Inc. J Clin Ultrasound 31:167–169, 2003
Sonographic diagnosis of Bouveret's syndrome
Authors: Venkatesh Sudhakar Kundapur , Thyagarajan Manigandan Subramaniam , Gujral Ratni Bajaj , Gupta Archana
Published: February 2003

A case of Bouveret's syndrome with obstruction of the duodenojejunal flexure diagnosed preoperatively by sonography is presented. A 48‐year‐old man with a history of cholelithiasis presented with colicky pain of 2 days' duration. Real‐time sonography revealed a fluid‐distended stomach and duodenum and a 3.4‐cm bright curvilinear echo with dense shadowing in the duodenojejunal flexure, suggesting a gallstone. In addition, there was pneumobilia and evidence of chronic cholecystitis. The findings were confirmed with CT, which showed a partially calcified gallstone at the duodenojejunal flexure, pneumobilia, and a fistulous communication between the gallbladder and duodenum. At surgery, a large gallstone was found impacted at the duodenojejunal flexure. The stone and gallbladder were successfully removed and the fistula repaired. The sonographic diagnosis of Bouveret's syndrome enabled early surgical intervention. © 2003 Wiley Periodicals, Inc. J Clin Ultrasound 31:163–166, 2003
Contrast‐enhanced power Doppler sonography and helical computed tomography for assessment of vascularity of small hepatocellular carcinomas before and after percutaneous ablation
Authors: Vilana Ramon , Llovet Josep M. , Bianchi Luis , Sanchez Marcelo , Pagés Mario , Sala Margarita , Gilabert Rosa , Nicolau Carlos , Garcia Angeles , Ayuso Carmen , Bruix Jordi , Bru Concepció
Published: February 2003

Purpose

We compared the usefulness of Levovist‐enhanced power Doppler imaging (PDI) and helical CT in the depiction of tumor vascularity before and after percutaneous ablation of small hepatocellular carcinomas (HCCs).

Methods

Thirty‐one cirrhotic patients with solitary unresectable HCCs smaller than 5 cm (mean size, 2.7 ± 0.8 cm; range, 1.5–5.0 cm) recruited over a 15‐month period were treated with percutaneous ethanol injection (n = 9) or radiofrequency ablation (n = 22). PDI, contrast‐enhanced PDI (using Levovist), and multiphase contrast‐enhanced helical CT were performed before and after percutaneous ablation, and vascularity findings were compared.

Results

Levovist significantly increased baseline intratumoral Doppler signals on PDI compared to non‐contrast PDI. The most frequent tumor vascularity pattern was heterogeneous (45%). Vascularity was identified in all tumors by both contrast‐enhanced PDI and helical CT before ablation. After percutaneous ablation, intratumoral vascularity was detected in 11 tumors by contrast‐enhanced PDI and in 15 tumors by CT. The sensitivity, specificity, and diagnostic accuracy of contrast‐enhanced PDI in demonstrating intratumoral vascularity, with CT being the gold standard, were 66%, 93%, and 81%, respectively. There was significant agreement between the 2 modalities in the depiction of tumor vascularity after ablation (κ = 0.6, p = 0.001). However, there were 5 false negatives and 1 false positive with contrast‐enhanced PDI. Complete tumor necrosis was achieved in 21 patients (68%).

Conclusions

There was a good concordance between contrast‐enhanced PDI and helical CT in the depiction of HCC vascularity before and after percutaneous ablation. However, although contrast‐enhanced PDI may be useful for real‐time guidance of treatment, its low sensitivity makes it inadequate to accurately assess the completeness of ablation. © 2003 Wiley Periodicals, Inc. J Clin Ultrasound 31:119–128, 2003
Development of rhythmic melatonin secretion from the pineal gland of embryonic mummichog (Fundulus heteroclitus)
Authors: Roberts Debra , Okimoto Darren K. , Parsons Cara , Straume Martin , Stetson Milton H.
Published: February 2003

The pineal gland of vertebrates produces and secretes the hormone melatonin in response to changes in the light‐dark cycle, with high production at night and low production during the day. Melatonin is thought to play an important role in synchronizing daily and/or seasonal physiological, behavioral, and developmental rhythms in vertebrates. In this study, the functional development of the pineal melatonin‐generating system was examined in the mummichog, Fundulus heteroclitus, an euryhaline teleost. In this species, the pineal gland contains an endogenous oscillator, ultimately responsible for timing the melatonin rhythm. Oocytes from gravid females were collected and fertilized in vitro from sperm collected from mature males. Skull caps containing attached pineal glands were obtained from F. heteroclitus embryos at different embryonic stages and placed in static or perfusion culture under various photoperiodic regimes. Rhythmic melatonin secretion from pineal glands of embryonic F. heteroclitus embryos exposed to a 12L:12D cycle in static culture was observed at five days post‐fertilization. The ontogeny of circadian‐controlled melatonin production from F. heteroclitus pineal glands exposed to constant darkness for five days was also seen at day five post‐fertilization. These data show that early development of the pineal melatonin‐generating system in this teleost occurs prior to hatching. Pre‐hatching development of the melatonin‐generating system may confer some selective advantage in this species in its interactions with the environment. J. Exp. Zool. 296A:56–62, 2003. © 2003 Wiley‐Liss, Inc.
Prolonged response to calling songs by the L3 auditory interneuron in female crickets (Acheta domesticus): Possible roles in regulating phonotactic threshold and selectiveness for call carrier frequency
Authors: Bronsert Michael , Bingol Hilary , Atkins Gordon , Stout John
Published: February 2003

L3, an auditory interneuron in the prothoracic ganglion of female crickets (Acheta domesticus) exhibited two kinds of responses to models of the male's calling song (CS): a previously described, phasically encoded immediate response; a more tonically encoded prolonged response. The onset of the prolonged response required 3–8 sec of stimulation to reach its maximum spiking rate and 6–20 sec to decay once the calling song ceased. It did not encode the syllables of the chirp. The prolonged response was sharply selective for the 4–5 kHz carrier frequency of the male's calling songs and its threshold tuning matched the threshold tuning of phonotaxis, while the immediate response of the same neuron was broadly tuned to a wide range of carrier frequencies. The thresholds for the prolonged response covaried with the changing phonotactic thresholds of 2‐ and 5‐day‐old females. Treatment of females with juvenile hormone reduced the thresholds for both phonotaxis and the prolonged response by equivalent amounts. Of the 3 types of responses to CSs provided by the ascending L1 and L3 auditory interneurons, the threshold for L3's prolonged response, on average, best matched the same females phonotactic threshold. The prolonged response was stimulated by inputs from both ears while L3's immediate response was driven only from its axon‐ipsilateral ear. The prolonged response was not selective for either the CS's syllable period or chirp rate. J. Exp. Zool. 296A:72–85, 2003. © 2003 Wiley‐Liss, Inc.
Synthesis of deuterated 4,4′‐diaminodiphenylsulfone (Dapsone) and related analogs
Authors: Gannett Peter M. , Johnson Edward M. , Grimes Michael A. , Myers Alan L. , Deavers Robert E. , Tracy Timothy S.
Published: February 2003

A general scheme for the synthesis of 4,4′‐diaminodiphenylsulfone‐d5 (Dapsone) from aniline‐d5 is described. The method may have general application and the preparation of the related analogs, 4,4′‐dimethylaminodiphenyl sulfone from aniline‐d5 and 4,4′‐dimethoxydiphenyl sulfone from phenol‐d5, is also described. Copyright © 2002 John Wiley & Sons, Ltd.
Novel solvent‐free labelling procedure with carbon‐14 diethyl malonate
Authors: Hernandez L. , Casanova E. , Loupy A. , Petit A.
Published: February 2003

A rapid and novel one‐pot radiochemical synthesis of 14C‐labelled esters has been developed using a combination of solvent‐free conditions and microwave irradiation. The method offers several advantages over the customary classical procedure. Copyright © 2002 John Wiley & Sons, Ltd.
Lipid content in the musculature of the lower leg assessed by fat selective MRI: Intra‐ and interindividual differences and correlation with anthropometric and metabolic data
Authors: Machann Jürgen , Bachmann Oliver P. , Brechtel Klaus , Dahl Dominik B. , Wietek Beate , Klumpp Bernhard , Häring Hans‐U. , Claussen Claus D. , Jacob Stephan , Schick Fritz
Published: February 2003

Purpose

To assess the muscular lipid content (LC) in different muscle groups of the lower leg by a magnetic resonance imaging technique working with chemical shift selective excitation, and comparison with anthropometric and metabolic data.

Materials and Methods

Examinations were performed in 67 volunteers (54 male/13 female, age 29 ± seven years) on a 1.5 T whole body imager, applying a highly selective spectral‐spatial technique for fat selective MRI. LC was measured in six calf muscles and correlated with body mass index (BMI), percent body fat (PFAT), and insulin sensitivity (IS) of the subjects.

Results

Mean muscular LC of all subjects was between 2.0% (Tibialis posterior [TP]) and 3.8% (Peroneus muscles) with female subjects showing a significantly higher LC in all muscle groups (P < 0.05 each). LCs correlated moderately with BMI (R between 0.39 [TP] and 0.53 [GM]) and with PFAT (R between 0.38 [TP] and 0.62 [GM]). Insulin‐resistant subjects showed slightly but not significantly increased LC compared to insulin‐sensitive subjects in BMI‐matched subgroups.

Conclusion

The fat‐selective MRI technique allows a reliable non‐invasive measure of muscular lipids – even in muscle groups with inherent low LC – within a relatively short measurement time of about three minutes. The presented data reveal interesting interrelationships between LC and anthropometric and metabolic data, and therefore provide new insight into muscular fat metabolism. J. Magn. Reson. Imaging 2003;17:350–357. © 2003 Wiley‐Liss, Inc.
Time‐resolved contrast‐enhanced pulmonary MR angiography using sensitivity encoding (SENSE)
Authors: Ohno Yoshiharu , Kawamitsu Hideaki , Higashino Takanori , Takenaka Daisuke , Watanabe Hirokazu , van Cauteren Marc , Fujii Masahiko , Hatabu Hiroto , Sugimura Kazuro
Published: February 2003

Purpose

To evaluate the relationship between gadolinium concentration and signal‐to‐noise ratio (SNR) on sensitivity encoding (SENSE) images, and determine the appropriate bolus injection protocol for visualizing pulmonary circulation.

Materials and Methods

Eighteen different gadolinium concentration phantoms (0, 0.01, 0.05, 0.1, 0.2, 0.4, 0.6, 0.8, 1.0, 1.2, 1.5, 2.0, 5.0, 10.0, 20.0, 30.0, 50.0, and 100.0 mmol/L) were analyzed to determine the relationship between gadolinium concentration and SNR on SENSE images in a phantom study. In an in vivo study, 3 mL (protocol A) or 6 mL (protocol B) of Gd‐DTPA BMA at 3 mL/second, and 5 mL of Gd‐DTPA BMA at 5 mL/second (protocol C) were administered to eight normal volunteers for contrast‐enhanced (CE) pulmonary MR angiography (MRA) with SENSE. The peak SNRs of pulmonary parenchyma and the difference in SNR between pulmonary artery (PA) and pulmonary vein (PV) at peak SNR in the PA were statistically evaluated.

Results

For each flip angle at each gadolinium concentration, the SNRs and contrast‐to‐noise ratios (CNRs) of the SENSE images were significantly lower than those acquired with a nonparallel imaging technique (P < 0.05). The peak SNR of the pulmonary parenchyma, and differences in SNR between the PA and PV at the peak SNR of the PA obtained with a 5‐mL/second bolus injection protocol were found to be significantly higher than those obtained with other protocols (P < 0.05).

Conclusion

3D‐CE‐MRA using SENSE demonstrated linearity between gadolinium concentration and SNR, and resulted in MRA with high spatial and temporal resolution with the aid of a sharp bolus injection protocol. J. Magn. Reson. Imaging 2003;17:330–336. © 2003 Wiley‐Liss, Inc.
Normal human left and right ventricular dimensions for MRI as assessed by turbo gradient echo and steady‐state free precession imaging sequences
Authors: Alfakih Khaled , Plein Sven , Thiele Holger , Jones Tim , Ridgway John P. , Sivananthan Mohan U.
Published: February 2003

Purpose

To establish normal ranges of left ventricular (LV) and right ventricular (RV) dimensions as determined by the current pulse sequences in cardiac magnetic resonance imaging (MRI).

Materials and Methods

Sixty normal subjects (30 male and 30 female; age range, 20–65) were examined; both turbo gradient echo (TGE) and steady‐state free precession (SSFP) pulse sequences were used to obtain contiguous short‐axis cine data sets from the ventricular apex to the base of the heart. The LV and RV volumes and LV mass were calculated by modified Simpson's rule.

Results

Normal ranges were established and indexed to both body surface area (BSA) and height. There were statistically significant differences in the measurements between the genders and between TGE and SSFP pulse sequences. For TGE the LV end‐diastolic volume (EDV)/BSA (mL/m2) in males was 74.4 ± 14.6 and in females was 70.9 ± 11.7, while in SSFP in males it was 82.3 ± 14.7 and in females it was 77.7 ± 10.8. For the TGE the LV mass/BSA (g/m2) in males was 77.8 ± 9.1 and in females it was 61.5 ± 7.5, while in SSFP in males it was 64.7 ± 9.3 and in females it was 52.0 ± 7.4. For TGE the RV EDV/BSA (mL/m2) in males was 78.4 ± 14.0 and in females it was 67.5 ± 12.7, while in SSFP in males it was 86.2 ± 14.1 and in females it was 75.2 ± 13.8.

Conclusion

We have provided normal ranges that are gender specific as well as data that can be used for age‐specific normal ranges for both SSFP and TGE pulse sequences. J. Magn. Reson. Imaging 2003;17:323–329. © 2003 Wiley‐Liss, Inc.
Investigating the stimulus‐dependent temporal dynamics of the BOLD signal using spectral methods
Authors: Müller Karsten , Mildner Toralf , Lohmann Gabriele , von Cramon D. Yves
Published: February 2003

Purpose

To compare several spectral parameters using different durations of visual hemifield stimulation in order to explore the different temporal behavior of the blood oxygenation‐level dependent (BOLD) signal in various brain regions.

Materials and Methods

Spectral methods were applied to three different groups of subjects with visual stimulation lasting 6, 12, and 30 seconds. Furthermore, diffusion weighting was applied in an interleaved way. The core of the data processing was the computation of the spectral density matrix using the multidimensional weighted covariance estimate. Spectral parameters of coherence and phase shift were computed.

Results

The correlation between signal changes and phase shifts was dependent on the duration of the visual stimulation. The shorter the duration of visual stimulation, the stronger the correlation between percentage signal change and phase shift.

Conclusion

The experiments with short and long stimuli differed mainly in the distribution of the activated voxels in the plane of percentage signal change and phase shift. It was revealed that the height of the signal change depends on the phase shift, whereas the diffusion weighting has no influence. J. Magn. Reson. Imaging 2003;17:375–382. © 2003 Wiley‐Liss, Inc.
Imaging the physical and morphological properties of a multi‐zone young articular cartilage at microscopic resolution
Authors: Xia Yang , Moody Jonathan B. , Alhadlaq Hisham , Hu Jiani
Published: February 2003

Purpose

To characterize a number of physical and morphologic properties of young articular cartilage. These properties include the anisotropy of T2relaxation, optical retardation, orientation of the collagen fibrils, total thickness of the tissue, number of histologic sub‐zones in the tissue, width of individual sub‐zones, and correlation between the depths of the local T2maxima and the local retardation minima.

Materials and Methods

Microscopic magnetic resonance imaging (μMRI) and polarized light microscopy (PLM) were used to examine three side‐by‐side specimens from a humeral head of a three‐month‐old beagle that exhibited a unique topographic heterogeneity from three‐zones centrally to multi‐zone peripherally.

Results

The centrally located specimen showed that the collagen fibrils across the tissue depth have a pattern of the classic three histologic sub‐zones (tangential, transitional, and radial). A much more complicated multi‐zone structure was found in the specimen located peripherally, with a second transitional zone and a second tangential zone located at the deep part of the tissue. We also showed that the orientation of the collagen fibrils that form the cocoon‐shaped territorial matrix surrounding the clusters of chondrocytes can be imaged by our PLM technique.

Conclusion

The results from the young animal in this report, together with our observations from older animals, demonstrate that MRI and PLM can be used to study the epiphyseal expansion of cartilage in young animals during its growth and subsequent loss in older animals. An illustrative model for the structure of collagen fibrils in a humeral head is suggested as an extension to the classic three‐zone model for young articular cartilage. J. Magn. Reson. Imaging 2003;17:365–374. © 2003 Wiley‐Liss, Inc.
1H magnetic resonance spectroscopy in human hydrocephalus
Authors: Braun Kees P.J. , Gooskens Rob H.J.M. , Vandertop W. Peter , Tulleken Cees A.F. , van der Grond Jeroen
Published: February 2003

Purpose

To evaluate cerebral metabolism in clinical hydrocephalus with 1H magnetic resonance spectroscopy (MRS).

Materials and Methods

In 24 children and adults with progressive, arrested, or normal pressure hydrocephalus, long‐echo time 1H MR spectra were acquired from periventricular white matter and intraventricular cerebrospinal fluid (CSF). Metabolite ratios, and the presence of lactate, were compared with 38 age‐matched controls.

Results

Metabolite ratios of patients were within the 95% confidence interval (CI) of controls. A small lactate resonance was detected in 20% of control and hydrocephalic subjects. Lactate was consistently visible in CSF spectra, though lactate concentrations were normal. The CSF lactate T2 was long in comparison with the known intracellular metabolite T2 relaxation times. In three neonates with hydrocephalus and spina bifida, 3‐hydroxybutyrate was detected in CSF in vivo.

Conclusion

Within the limits of the present methods, 1H MRS could not detect cerebral metabolic abnormalities in human hydrocephalus and provided no additional diagnostic information. The long T2 of lactate in CSF explains its high visibility. Hence, the detection of lactate in spectra acquired from voxels that contain CSF does not necessarily imply cerebral ischemia. J. Magn. Reson. Imaging 2003;17:291–299. © 2003 Wiley‐Liss, Inc.
BOLD‐fMRI response vs. transcranial magnetic stimulation (TMS) pulse‐train length: Testing for linearity
Authors: Bohning Daryl E. , Shastri Ananda , Lomarev Mikhail P. , Lorberbaum Jeffrey P. , Nahas Ziad , George Mark S.
Published: February 2003

Purpose

To measure motor and auditory cortex blood oxygenation level‐dependent (BOLD) functional magnetic resonance imaging (fMRI) response to impulse‐like transcranial magnetic stimulation (TMS) pulses as a function of train length.

Materials and Methods

Interleaved with fMRI at 1.5 T, TMS pulses 0.3‐msec long were applied at 1 Hz to the motor cortex area for thumb. Six subjects were studied in a TR = 1 second session administering trains of 1, 2, 4, 8, and 16 pulses, and a TR = 3 seconds session administering trains of 1, 2, 4, 8, 16, and 24 pulses. A simple hemodynamic model with finite recovery and saturation was used to quantitatively characterize the BOLD‐fMRI response as a function of train length.

Results

In both the activations directly induced in motor cortex by TMS and the indirect activations in auditory cortex caused by the sound of the TMS coil firing, the BOLD‐fMRI responses to multiple pulses were well described by a summation of single‐pulse impulse functions.

Conclusion

Up to 24 discrete pulses, BOLD‐fMRI response to 1 Hz TMS in both motor cortex and auditory cortex were consistent with a linear increase in amplitude and length with train length, possibly suggesting that stimuli of 1 to 2 seconds may be too long to represent impulses. J. Magn. Reson. Imaging 2003;17:279–290. © 2003 Wiley‐Liss, Inc.
Does job insecurity lead to impaired well‐being or vice versa? Estimation of cross‐lagged effects using latent variable modelling
Authors: Hellgren Johnny , Sverke Magnus
Published: February 2003

Although research suggests that job insecurity is associated with impaired employee well‐being, there is insufficient empirical evidence to draw any causal inferences since most studies are cross‐sectional and thus do not control for previous levels of health symptoms. We used longitudinal questionnaire data to investigate the direction of the relationship between job insecurity and health complaints. After controlling for prior levels of mental and physical health complaints and five other variables that could potentially confound the results (gender, age, organizational tenure, family status, and education), the results of latent variable modelling showed that the cross‐lagged effect of job insecurity on mental health complaints, one year later, was significant whereas the reversed effects of mental and physical health complaints on subsequent insecurity were non‐significant. However, there was no significant cross‐lagged effect of job insecurity on physical health complaints. The results provide empirical support for the theoretical notion that job insecurity leads to health complaints, and imply that prior levels of health should be taken into consideration in order to explain the relative effect of perceived job insecurity on the physical and mental health of the workforce. Copyright © 2003 John Wiley & Sons, Ltd.
Where intrinsic job satisfaction fails to work: national moderators of intrinsic motivation
Authors: Huang Xu , Van De Vliert Evert
Published: February 2003

This study sought for national characteristics that moderate the individual‐level relationship between job characteristics and job satisfaction. Data from two distinct questionnaire surveys administered to 107,292 employees in 49 countries was analyzed by employing multilevel modeling. Results showed that the link between intrinsic job characteristics and job satisfaction is stronger in richer countries, countries with better governmental social welfare programs, more individualistic countries, and smaller power distance countries. By contrast, extrinsic job characteristics are strongly and positively related to job satisfaction in all countries. In addition, we found that intrinsic job characteristics tend to produce motivating satisfaction in countries with good governmental social welfare programs irrespective of the degree of power distance, while they do not tend to work so in countries with poor governmental social welfare programs as well as a large power distance culture. Socio‐economic and cultural approaches to explaining cross‐national variation in work motivation are discussed. Copyright © 2003 John Wiley & Sons, Ltd.
Experimental study of SAR reduction on commercial products and shielding materials in mobile phone applications
Authors: Fung L. C. , Leung S. W. , Chan K. H.
Published: February 2003

There has been a recent increase in public concern regarding human safety due to the exposure of humans to radio frequency (RF) electromagnetic energy radiated by mobile phone handsets. This paper presents an experimental study of the effectiveness of various commercially available specific absorption rate (SAR) reduction products and shielding materials that can be externally attached to the handsets. The results have indicated that the effectiveness of both the SAR reduction products and the shielding materials in reducing SARs are generally below 10%. © 2003 Wiley Periodicals, Inc. Microwave Opt Technol Lett 36: 419–422, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.10780
A printed diversity dual‐band monopole antenna for WLAN operation in the 2.4‐ and 5.2‐GHz bands
Authors: Wu Tzuenn‐Yih , Fang Shyh‐Tirng , Wong Kin‐Lu
Published: February 2003

A novel printed diversity dual‐band monopole antenna integrated on a PCMCIA network card for WLAN operation in the 2.4‐ and 5.2‐GHz bands is proposed. The antenna comprises two substantially orthogonal printed monopoles with a straight strip of longer length for the lower‐mode operation (2.4‐GHz band) and a protruded strip of shorter length for the upper‐mode operation (5.2‐GHz band). In addition, the two monopoles are placed symmetrically with respect to a protruded ground plane of double‐T shape, which leads to good isolation obtained between the antenna's two feeding ports. With the system switching between the antenna's two ports, maximum signal strength for WLAN operation can be obtained, and system performance can be enhanced. © 2003 Wiley Periodicals, Inc. Microwave Opt Technol Lett 36: 436–439, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.10784
Initial coding results with a millimeter‐wave six‐port QPSK receiver
Authors: Song Zhiyan , Tatu Serioja , Soleymani Mohammad Reza , Wu Ke , Bosisio Renato G.
Published: February 2003

In this paper, error‐control coding is used with a six‐port direct‐digital QPSK receiver [1] in an AWGN channel. The direct‐conversion wideband six‐port millimeter wave receiver proposed herein meets the needs of MMIC mass‐market wireless communications. Convolutional code and Turbo code are used as the channel codes for the first time in this type of receiver. The BER results for the convolutional code, turbo code, and the uncoded system in the six‐port receiver, are presented at a bit rate of 1 Mbps. © 2003 Wiley Periodicals, Inc. Microwave Opt Technol Lett 36: 465–467, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.10791
Multiple‐frequency photonic bandgap microstrip structures based on defects insertion
Authors: Griol A. , Mira D. , Martinez A. , Marti J.
Published: February 2003

In this paper, microstrip photonic bandgap structures based on etching a nonperiodic pattern of circles in the ground plane of a microstrip line are investigated. Three topologies based on placing two defects in a periodic circle pattern, with a different spacing between them for each structure, are considered and their responses are compared. Multiple‐frequency and bandwidth‐tuned bandgaps are obtained. © 2003 Wiley Periodicals, Inc. Microwave Opt Technol Lett 36: 479–481, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.10795
A fast synthesis algorithm of adaptive beams for smart antennas
Authors: Li Jinhua , Jin Ronghong , Sheng Yanci
Published: February 2003

An amplitude approaching algorithm (AAA) for the pattern synthesis of adaptive arrays is presented in this paper. Furthermore, the algorithm is amended by the Newton downhill method. Simulations show that the main lobe and side lobe can be controlled efficiently, and the algorithm converges more quickly and steadily. © 2003 Wiley Periodicals, Inc. Microwave Opt Technol Lett 36: 503–507, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.10804
Identification of estrogen‐regulated genes in the mouse uterus using a delayed‐implantation model
Authors: Lee Sukwon , Lee Seung‐Ah , Shim Chanseob , Khang Inkoo , Lee Kyung‐Ah , Park Young‐Mee , Kang Byung‐Moon , Kim Kyungjin
Published: February 2003

Gonadal steroid hormones are known to modulate the implantation of the blastocyst, but how the controlling genetics are regulated remains largely unknown. Using a delayed‐implantation model, we examined estrogen‐regulated genes (ERGs) in the mouse uterus using the differential‐display reverse transcription‐polymerase chain reaction (DD RT‐PCR). Pregnant mice were ovariectomized and injected daily with progesterone (P, 1 mg/mouse), followed by a single injection of estrogen (E, 200 ng/mouse); 24 or 48 hr later, total RNA was extracted from the uterus. Reverse Northern analysis verified the expression patterns of 36 clones out of thousands of RNA species. Only five clones had mRNA levels that were modified, whereas other mRNAs were unchanged or not detectable. Sequence analysis of these, using the Basic Local Alignment Search Tool (BLAST) service, revealed that four of these clones were novel; one clone, designated ERG10, was found to be the mouse homologue of that deleted in oral cancer DOC‐1. DOC‐1 mRNA was detected all tissues examined, but only in the uterus and cervix was markedly increased 12 hr after E administration, it returned to basal level by 48 hr. One of the novel genes, designated ERG8, had three different forms of mRNAs and was expressed ubiquitously in all examined tissues. In the uterus, the mRNA level of ERG8 also increased 12 hr after E administration. These results suggest that during the implantation process, E differentially regulates several genes depending on cell type. Uterine‐specific induction of newly found genes, such as ERG8 and 10, by E appears to be important for the early implantation process. Mol. Reprod. Dev. 64: 405–413, 2003. © 2003 Wiley‐Liss, Inc.
Alterations and reversibility in the chromatin, cytoskeleton and development of pig oocytes treated with roscovitine
Authors: Ju Jyh‐Cherng , Tsay Chih , Ruan Chi‐Wai
Published: February 2003

Germinal vesicle (GV) breakdown in mammalian oocytes is regulated by the activation of maturation promoting factor (MPF). We investigated a specific cdc2 kinase inhibitor, roscovitine, to maintain pig oocytes in the GV stage. Cumulus‐oocyte complexes (COCs) were aspirated from slaughterhouse ovaries and cultured for 44 hr in NCSU#23 medium containing different levels of roscovitine (0, 10, 20, 30, 40, 50 μM in Experiment 1 and 0, 40, 60, 80, 100, 120 μM in Experiment 2). The COCs were cultured for another 44 hr after removal of the chemical. Twenty oocytes in each group were fixed at 44 hr for immunocytochemical labeling of the cytoskeleton and the rest (∼20/group) were fixed at the end of 88 hr after culture. Results showed that the inhibition of the oocyte in the GV stage was not effective when 10–50 μM (Experiment 1) of roscovitine were used (19–34%). When oocytes were released from the inhibitor, similar proportions (70–83%) of oocytes were observed in the MII or advanced stages among treatments. However, when higher concentrations of roscovitine were used (Experiment 2), significantly greater inhibitory effect was observed at the levels of 80–120 μM with 83–91% oocytes being blocked in the GV stage when compared to the control (9%) and the 40–60 μM (27–43%) groups (P < 0.05). Although 15–21% of the oocytes showed abnormal MII morphology with aberrant meiotic spindles and/or formation of cytoplasmic microtubules, a substantial number of oocytes resumed meiosis and reached MII stage at 44 hr after removal of this chemical. In Experiment 3, different concentrations of roscovitine (0, 20, 40, and 80 μM) were tested to examine the length of intervals (0, 11, 22, 33, and 44 hr) for an effective inhibition. Results showed that the inhibitory effect was significantly more prominent at 22 hr than that at 33 and 44 hr after roscovitine treatment in all treatment groups (P < 0.05). This study demonstrated that roscovitine‐treated oocytes resumed meiosis after removal of the inhibitor. This could provide flexibility for studying porcine oocyte development and embryo cloning and may have application in other species. Mol. Reprod. Dev. 64: 482–491, 2003. © 2003 Wiley‐Liss, Inc.
Development of the signalling pathways associated with sperm capacitation during epididymal maturation
Authors: Baker Mark A. , Lewis Beverley , Hetherington Louise , Aitken R. John
Published: February 2003

As spermatozoa mature within the epididymis they acquire the potential for capacitation and ultimately fertilization. In biochemical terms, the former is reflected in the progressive activation of a signal transduction pathway characterized by cAMP‐mediated induction of phosphotyrosine expression on the sperm tail. In this study, we have examined the cellular mechanisms controlling this maturational event. Caput epididymal spermatozoa exhibited tyrosine phosphorylation on the sperm head that was largely unresponsive to cAMP and not significantly impaired by removal of extracellular HCO3−. In contrast, caudal epididymal spermatozoa exhibited low levels of phosphorylation on the sperm head, yet responded dramatically to cAMP by phosphorylating a new set of proteins on the sperm tail via mechanisms that were highly dependent on extracellular HCO3−. The impact of extracellular HCO3− depletion on caudal cells was not associated with a significant change in the redox regulation of cAMP but could be fully reversed by buffering the intracellular pH with N‐Tris[Hydroxymethyl]methyl‐3‐amino‐propanesulfonic acid (TAPS). The pattern of tyrosine phosphorylation was also profoundly influenced by the presence or absence of added extracellular calcium. In the presence of this cation, only caudal spermatozoa could respond to increased extracellular cAMP with tyrosine phosphorylation of the sperm tail. However, in calcium‐depleted medium, this difference completely disappeared. Under these conditions, caput and caudal spermatozoa were equally competent to exhibit phosphotyrosine expression on the sperm tail in response to cAMP. These results emphasize the pivotal role played by calcium and HCO3− in modulating the changes in tyrosine phosphorylation observed during epididymal maturation. Mol. Reprod. Dev. 64: 446–457, 2003. © 2003 Wiley‐Liss, Inc.
c‐fos and estrogen receptor gene expression pattern in the rat uterine epithelium during the estrous cycle
Authors: Mendoza‐Rodríguez C. Adriana , Merchant‐Larios Horacio , Segura‐Valdez Maria L. , Moreno‐Mendoza Norma , Cruz María E. , Arteaga‐López Paola , Camacho‐Arroyo Ignacio , Domínguez Roberto , Cerbón Marco
Published: February 2003

Different studies in ovariectomized estrogen treated animals support the idea that c‐fos plays a role in the proliferation of uterine epithelial cells. However, these studies invite us to reassess the role played by c‐fos in epithelial cell types of the endometrium during the estrous cycle. The present study was undertaken to determine the c‐fos and estrogen receptor (ER) gene expression pattern in the rat uterine epithelium during the estrous cycle in which natural and cyclic changes of steroid hormones occur, and correlate these changes with the proliferation status of this cellular types. Proliferation was assessed during the estrous cycle using bromodeoxyuridine incorporation to DNA. ERα and β proteins were assessed by immunohistochemistry. The regulation of c‐fos gene expression in the uterus of intact animals during the estrous cycle was evaluated using both in situ hybridization and immunohistochemistry. Estradiol (E2) and progesterone (P4) plasma levels were assessed by radioimmunoassay. The results indicated that luminal (LE) and glandular epithelia (GE) presented maximal proliferation during the metestrus (M) and the diestrus (D) days. However, during the proestrus (P) day only LE presented proliferation, and during the estrus (E) day only the stromal cells proliferated. A marked immunostaining for ERα was detected in both LE and GE cells during the early phases of the cycle but diminished on the P and the E day. In contrast, ERβ was undetectable in both epithelia during all stages of the cycle. The highest c‐fos mRNA level was detected in both epithelia on the M day, followed by a significant reduction during the other days of the cycle. The highest protein content was observed on the M and D days, and the minimal value was detected on the E day. The c‐Fos protein level in LE was increased during M and D days, presenting a high correlation with the cellular proliferation pattern of this cell type. In conclusion, the overall results indicate that c‐Fos protein presented a good correlation with uterine epithelial cell proliferation of LE. In the case of GE, the same tendency was observed, although no significant correlation was found. Both in LE and GE, c‐fos mRNA did not strictly correlate with its protein levels. c‐fos seems to have a postranscriptional regulation in uterine epithelial cells during the rat's estrous cycle. Mol. Reprod. Dev. 64: 379–388, 2003. © 2003 Wiley‐Liss, Inc.
Efficient measurement and calculation of MR diffusion anisotropy images using the Platonic variance method
Authors: Akkerman Erik M.
Published: February 2003

The Platonic variance method produces MR diffusion anisotropy (DA) images with a minimum amount of computational effort. It can be programmed in a self‐contained MR sequence, thus eliminating the need for postprocessing on a separate workstation. The method uses gradient acquisition schemes, based on Platonic solids: the “icosahedric” scheme (N = 6), the “dodecahedric” scheme (N = 10), and combinations thereof. For these schemes the average of the diffusion tensor eigenvalues equals the average of the measured apparent diffusion coefficients (ADCs), and the variance of the eigenvalues equals 5/2 times the variance of the diffusion coefficients. This results in compact expressions for anisotropy measures, directly in terms of the acquired images, i.e., without calculating the eigenvalues or even the tensor elements. The resulting anisotropy images were shown to be identical to the ones traditionally derived. It is expected that this method will considerably promote the routine use of DA imaging. Magn Reson Med 49:599–604, 2003. © 2003 Wiley‐Liss, Inc.
Quantitative measurements of proton spin‐lattice (T1) and spin–spin (T2) relaxation times in the mouse brain at 7.0 T
Authors: Guilfoyle David N. , Dyakin Victor V. , O'Shea Jacqueline , Pell Gaby S. , Helpern Joseph A.
Published: February 2003

The goal of this work is to provide regional T1 and T2 values at a field strength of 7 T for the normal mouse brain at 6 weeks and 1 year old. A novel segmented snapshot FLASH sequence was used to measure T1 in the hippocampus, corpus callosum, and the retrosplenial granular (RSG) cortex; T2 measurements were made in the same regions using a single spin echo sequence repeated at six separate echo times. Both T1 and T2 measurements were validated with phantom measurements. Magn Reson Med 49:576–580, 2003. © 2003 Wiley‐Liss, Inc.
Myocardial triglycerides and systolic function in humans: In vivo evaluation by localized proton spectroscopy and cardiac imaging
Authors: Szczepaniak Lidia S. , Dobbins Robert L. , Metzger Gregory J. , Sartoni‐D'Ambrosia Greta , Arbique Debbie , Vongpatanasin Wanpen , Unger Roger , Victor Ronald G.
Published: February 2003

Recent experimental data suggest that adiposity directly damages the heart by promoting ectopic deposition of triglyceride, a process known as myocardial steatosis. The goal of this study was to develop and validate proton magnetic resonance spectroscopy (1H MRS) as an in vivo tool to measure myocardial lipid content. Complementary studies in rat tissue ex vivo and in 15 healthy humans in vivo provided evidence that 1H MRS constitutes a reproducible technique for the measurement of myocardial triglyceride. In myocardial tissue from Zucker rats, the 1H MRS measurement of triglyceride matched that obtained by biochemical measurement (P < 0.001). In human subjects triglyceride was evident in the hearts of even the very lean individuals and was elevated in overweight and obese subjects. Increased myocardial triglyceride content was accompanied by elevated LV mass and suppressed septal wall thickening as measured by cardiac imaging. Magn Reson Med 49:417–423, 2003. © 2003 Wiley‐Liss, Inc.
Detecting stiff masses using strain‐encoded (SENC) imaging
Authors: Osman Nael F.
Published: February 2003

A method is proposed for detecting stiff masses using strain‐encoded (SENC) magnetic resonance imaging (MRI). An object of interest is compressed to produce local strain distribution that depends on local elasticity, where intensities correlate with the local through‐imaging‐plane strain component. Because the strain is lower inside a stiff mass than in the surrounding soft tissue, an intensity contrast in the resulting images would enable direct detection of the mass without postprocessing. The technique was validated by a phantom experiment in which a gel phantom with a stiff region was used. The advantages of the proposed method include short imaging time and uncomplicated postprocessing. However, in its current form the technique does not measure elasticity. Magn Reson Med 49:605–608, 2003. © 2003 Wiley‐Liss, Inc.
Quantitative imaging of magnetization transfer using an inversion recovery sequence
Authors: Gochberg Daniel F. , Gore John C.
Published: February 2003

A new imaging method has been developed for quantitatively measuring magnetization transfer (MT). It uses a simple inversion recovery sequence, although one with very short (milliseconds) inversion times, and thus can be implemented on clinical imaging systems with little modification to existing pulse sequences. The sequence requires an inversion pulse with a length much longer than T2m (typically 10 μs) and much shorter than T2f (typically tens of ms) and 1/kmf (typically tens of ms), where T2m and T2f are the transverse relaxation times of the immobile macromolecular and free water protons, respectively, and kmf is the rate of MT between these populations. The resultant NMR signal is sensitive to MT when this inversion pulse affects the mobile and immobile proton pools to different degrees and by appropriate analysis of the signals obtained for different inversion times, quantitative information can be derived on the macromolecular content and exchange rates within the sample. The method has been used in conjunction with echo planar imaging to produce maps of the spatial distribution of the macromolecular content and MT rate in cross‐linked bovine serum albumin. Comparisons between this method and other quantitative MT techniques are discussed. Magn Reson Med 49:501–505, 2003. © 2003 Wiley‐Liss, Inc.
Macrophage labeling by SPIO as an early marker of allograft chronic rejection in a rat model of kidney transplantation
Authors: Beckmann N. , Cannet C. , Fringeli‐Tanner M. , Baumann D. , Pally C. , Bruns C. , Zerwes H.‐G. , Andriambeloson E. , Bigaud M.
Published: February 2003

Anatomical and functional information (renography, perfusion) was obtained by MRI in a life‐supporting transplantation model, in which Lewis rats received kidneys from Fisher 344 donors. Renography and perfusion analyses were carried out with Gd‐DOTA and small particles of iron oxide (SPIO), respectively. Starting 12 weeks posttransplantation, images from grafts of untreated recipients exhibited distinctive signal attenuation in the cortex. Animals treated with cyclosporin (Sandimmune Neoral; Novartis Pharma, Basel, Switzerland) to prevent acute rejection showed a signal attenuation in the cortex at 33 weeks posttransplantation, while kidneys from rats treated additionally with everolimus (Certican; Novartis), a rapamycin derivative, had no changes in anatomical appearance. A significant negative correlation was found between the MRI cortical signal intensity and the histologically determined iron content in macrophages located in the cortex. Renography revealed a significantly reduced functionality of the kidneys of untreated controls 33 weeks after transplantation, while no significant changes in perfusion were observed in any group of rats. These results suggest the feasibility, by labeling macrophages with SPIO, of detecting signs of graft rejection significantly earlier than when changes in function occur. Monitoring early changes associated with chronic rejection can have an impact in preclinical studies by shortening the duration of the experimental period and by facilitating the investigation of novel immunomodulatory therapies for transplantation. Magn Reson Med 49:459–467, 2003. © 2003 Wiley‐Liss, Inc.
SMASH navigators
Authors: Bydder M. , Atkinson D. , Larkman D.J. , Hill D.L.G. , Hajnal J.V.
Published: February 2003

The additional data acquired when using multiple receiver coils is commonly used to improve SNR or reduce acquisition times. It may also be used to remove image artifacts by selectively replacing corrupt data. In the present study, a correction scheme is presented based on simultaneous acquisition of spatial harmonics (SMASH) that enables detection and correction of motion artifacts caused by 2D translations. Newly measured data is compared with predictions from previously measured data by making negative and positive spatial harmonics. Differences are attributed to motion occurring in the interval between the acquisition of separate phase encode lines and correction parameters are determined. Two types of rigid body motion are considered: 1) object and coil array move, and 2) object only moves, since each causes different phase errors in k‐space. Simulation, phantom, and volunteer experiments demonstrate the validity of the technique. Magn Reson Med 49:493–500, 2003. © 2003 Wiley‐Liss, Inc.
Delayed gadolinium‐enhanced MRI of cartilage (dGEMRIC) in early knee osteoarthritis
Authors: Tiderius Carl Johan , Olsson Lars E. , Leander Peter , Ekberg Olle , Dahlberg Leif
Published: February 2003

Delayed contrast‐enhanced MRI of cartilage (dGEMRIC) is a noninvasive technique to study cartilage glycosaminoglycan (GAG) content in vivo. This study evaluates dGEMRIC in patients with preradiographic degenerative cartilage changes. Seventeen knees in 15 patients (age 35–70) with arthroscopically verified cartilage changes (softening and fibrillations) in the medial or lateral femoral compartment, knee pain, and normal weight‐bearing radiography were included. MRI (1.5 T) was performed precontrast and at 1.5 and 3 hr after an intravenous injection of Gd‐DTPA2−at 0.3 mmol/kg body weight.T1measurements were made in regions of interest in medial and lateral femoral cartilage using sets of five turbo inversion recovery images. Precontrast,R1(R1= 1/T1, 1/s) was slightly lower in diseased compared to reference compartment, indicating increased hydration (P= 0.01). Postcontrast,R1was higher in diseased than in reference compartment at 1.5 hr, 3.45 ± 0.90 and 2.64 ± 0.58 (mean ± SD), respectively (P< 0.01), as well as at 3 hr, 2.94 ± 0.60 and 2.50 ± 0.37, respectively (P= 0.01). The washout of the contrast medium was faster in diseased cartilage as shown by a higherR1at 1.5 than at 3 hr in the diseased but not in the reference compartment. In conclusion, dGEMRIC can identify GAG loss in early stage cartilage disease with a higher sensitivity at 1.5 than 3 hr. Magn Reson Med 49:488–492, 2003. © 2003 Wiley‐Liss, Inc.