bluuebunny/crossref_metadata_2025 huggingface dataset:
A 4′‐Phosphopantetheinyl Transferase Mediates Non‐Ribosomal Peptide Synthetase Activation in Aspergillus fumigatus
Authors: Neville Claire , Murphy Alan , Kavanagh Kevin , Doyle Sean
Published: February 2005

Aspergillus fumigatus is a significant human pathogen. Non‐ribosomal peptide (NRP) synthesis is thought to be responsible for a significant proportion of toxin and siderophore production in the organism. Furthermore, it has been shown that 4′‐phosphopantetheinylation is required for the activation of key enzymes involved in non‐ribosomal peptide synthesis in other species. Here we report the cloning, recombinant expression and functional characterisation of a 4′‐phosphopantetheinyl transferase from A. fumigatus and the identification of an atypical NRP synthetase (Afpes1), spanning 14.3 kb. Phylogenetic analysis has shown that the NRP synthetase exhibits greatest identity to NRP synthetases from Metarhizium anisolpiae (PesA) and Alternaria brassicae (AbrePsy1). Northern hybridisation and RT‐PCR analysis have confirmed that both genes are expressed in A. fumigatus. A 120 kDa fragment of the A. fumigatus NRP synthetase, containing a putative thiolation domain, was cloned and expressed in the baculovirus expression system. Detection of a 4′‐phosphopantetheinylated peptide (SFSAMK) from this protein, by MALDI‐TOF mass spectrometric analysis after coincubation of the 4′‐phosphopantetheinyl transferase with the recombinant NRP synthetase fragment and acetyl CoA, confirms that it is competent to play a role in NRP synthetase activation in A. fumigatus. The 4′‐phosphopantetheinyl transferase also activates, by 4′‐phosphopantetheinylation, recombinant α‐aminoadipate reductase (Lys2p) from Candida albicans, a key enzyme involved in lysine biosynthesis.
Mechanism of Ni Film CVD with a Ni(ktfaa)2 Precursor on a Copper Substrate
Authors: Bakovets V. V. , Mitkin V. N. , Gelfond N. V.
Published: February 2005

The mechanisms of pyrolysis in He and reduction in H2 of a Ni(ktfaa)2 chelate and nickel film deposition on copper substrates are discussed. The Ni films produced by CVD with the Ni(ktfaa)2 chelate as a precursor are continuous. Pyrolysis of the Ni(ktfaa)2 chelate takes place above 300 °C. The hydrogen atmosphere allows the reaction temperature to be decreased to 213 °C, but the film deposition rate is low. 300 °C is the optimal temperature for continuous Ni film deposition on Cu substrates. The mechanism of hydrogen interaction with the adsorbed Ni(ktfaa)2 chelate is discussed.
Growth Kinetics, Composition, and Morphology of Co3O4 Thin Films Prepared by Pulsed Liquid‐Injection MOCVD
Authors: Burriel M. , Garcia G. , Santiso J. , Abrutis A. , Saltyte Z. , Figueras A.
Published: February 2005

Cobalt oxide films were grown by pulsed liquid injection MOCVD using Co(thd)2 dissolved in monoglyme as the precursor. The structure, morphology, and growth rate of the layers deposited on silicon substrates were studied as a function of solution concentration, deposition temperature, and oxygen partial pressure. X‐ray diffraction (XRD) of films deposited from 350 °C to 540 °C showed a pure Co3O4 spinel structure and no CoO was detected, even at the lowest oxygen pressure. X‐ray photoelectron spectroscopy (XPS) was used to study the surface composition and oxidation states. Surprisingly, XPS spectra recorded for most of the films seemed to correspond to CoO. This unexpected oxidation state on the surface was assigned to the effect of the high density of edges and corners present in the surface morphology.
CD4+ T cell immunity against the human papillomavirus‐18 E6 transforming protein in healthy donors: identification of promiscuous naturally processed epitopes
Authors: Facchinetti Valeria , Seresini Samantha , Longhi Renato , Garavaglia Claudio , Casorati Giulia , Protti Maria Pia
Published: February 2005

Infection by ‘high‐risk’ human papillomaviruses (HPV) is associated with the development of neoplastic lesions. HPV‐18 is responsible for a very aggressive form of cancer and poor survival. As for other HPV types, immune surveillance has probably a role in the control of the infection. However, very little is known on HPV‐18 immunogenicity. CD4+ T cells from 16 healthy donors were tested ex vivo for reactivity to synthetic peptides corresponding to 3 sequences on the HPV‐18 E6 transforming protein predicted by bioinformatics as promiscuous HLA‐DR ligands, and to the recombinant E6 protein. We found 3 donors with CD4+ T cells that specifically proliferated in the presence of HPV‐18 E6 antigens and produced IFN‐γ in the presence of the E6 protein. We then propagated CD4+ T cell lines and clones from the responsive subjects to better characterize the recognized sequences. We show that E652–66 and E697–111 are indeed promiscuous and, most importantly, they contain naturally processed epitopes. Collectively, our data indicate that healthy donors may develop spontaneous CD4 immunity against HPV‐18 E6 epitopes, thus strongly suggesting the potential for this protein to elicit in the host a natural productive immune response.
Intra‐ and inter‐allelic ordering of T cell receptor β chain gene assembly
Authors: Khor Bernard , Sleckman Barry P.
Published: February 2005

Allelic exclusion at the TCRβ locus mandates that gene assembly be regulated in a manner that permits feedback inhibition of further complete TCRβ rearrangements upon pre‐TCR expression. Here we show that assembly of TCRβ chain genes from Vβ, Dβ and Jβ gene segments is intra‐allelically ordered, proceeding primarily through DJβ, and not VDβ, intermediates. This ensures that Vβ to DJβ rearrangement, which can be feedback inhibited, is the final step in the assembly process. A newly assembled VDJβ rearrangement must be tested to determine if it is in‐frame before Vβ to DJβ rearrangement is permitted on the alternate allele. This inter‐allelic ordering may occur through a general inefficiency of Vβ to DJβ rearrangement and/or through static differences in accessibility of the two TCRβ alleles. However, we find that within the regulatory context of allelic exclusion, Vβ to DJβ rearrangement proceeds to completion on both alleles. Furthermore, all possible VDJβ rearrangements are not completed on one allele before Vβ to DJβ rearrangement is initiated on the alternate allele. Together, these data support a dynamic model of inter‐allelic accessibility that permits the ordered and efficient assembly of complete variable region genes on both TCRβ alleles during T cell development.
Sexual dimorphism of growth plate prehypertrophic and hypertrophic chondrocytes in response to testosterone requires metabolism to dihydrotestosterone (DHT) by steroid 5‐alpha reductase type 1
Authors: Raz P. , Nasatzky E. , Boyan B.D. , Ornoy A. , Schwartz Z.
Published: February 2005

Rat costochondral growth plate chondrocytes exhibit sex‐specific and cell maturation dependent responses to testosterone. Only male cells respond to testosterone, although testosterone receptors are present in both male and female cells, suggesting other mechanisms are involved. We examined the hypothesis that the sex‐specific response of rat costochondral cartilage cells to testosterone requires further metabolism of the hormone to dihydrotestosterone (DHT). Resting zone (RC) and growth zone (GC, prehypertrophic and upper hypertrophic zones) chondrocytes from male and female Sabra strain rats exhibited sex‐specific responses to testosterone and DHT: only male cells were responsive. Testosterone and DHT treatment for 24 h caused a comparable dose‐dependent increase in [3H]‐thymidine incorporation in quiescent preconfluent cultures of male GC cells, and a comparable increase in alkaline phosphatase specific activity in confluent cultures. RC cells responded in a differential manner to testosterone and DHT. Testosterone decreased DNA synthesis in male RC cells but DHT had no effect and alkaline phosphatase specific activity of male RC cells was unaffected by either hormone. Inhibition of steroid 5α‐reductase activity with finasteride (1, 5, or 10 μg/ml), reduced the response of male GC cells to testosterone in a dose‐dependent manner, indicating that metabolism to DHT was required. RT‐PCR showed that both male and female cells expressed mRNAs for steroid 5α‐reductase type 1 but lacked mRNAs for the type 2 form of the enzyme. Male cells also exhibited 5α‐reductase activity but activity of this enzyme was undetectable in female cells. These observations show that sex‐specific responses of rat growth zone chondrocytes to testosterone requires the further metabolism of the hormone to DHT and that the effect of DHT in the male growth plate is maturation‐state dependent. Failure of female chondrocytes to respond to testosterone may reflect differences in testosterone metabolism, since these cells possess greater ability to aromatize the hormone to estradiol. © 2004 Wiley‐Liss, Inc.
Over‐expression of fibroblast growth factor‐2 causes defective bone mineralization and osteopenia in transgenic mice
Authors: Sobue T. , Naganawa T. , Xiao L. , Okada Y. , Tanaka Y. , Ito M. , Okimoto N. , Nakamura T. , Coffin J.D. , Hurley M.M.
Published: February 2005

Over‐expression of human FGF‐2 cDNA linked to the phosphoglycerate kinase promoter in transgenic (TgFGF2) mice resulted in a dwarf mouse with premature closure of the growth plate and shortening of bone length. This study was designed to further characterize bone structure and remodeling in these mice. Bones of 1–6 month‐old wild (NTg) and TgFGF2 mice were studied. FGF‐2 protein levels were higher in bones of TgFGF2 mice. Bone mineral density was significantly decreased as early as 1 month in femurs from TgFGF2 mice compared with NTg mice. Micro‐CT of trabecular bone of the distal femurs from 6‐month‐old TgFGF2 mice revealed significant reduction in trabecular bone volume, trabecular number (Tb.N), and increased trabecular separation (Tb.Sp). Osteoblast surface/bone surface, double‐labeled surface, mineral apposition rate, and bone formation rates were all significantly reduced in TgFGF2 mice. There were fewer TRAP positive osteoclasts in calvaria from TgFGF2 mice. Quantitative histomorphometry showed that total bone area was similar in both genotypes, however percent osteoclast surface, and osteoclast number/bone surface were significantly reduced in TgFGF2 mice. Increased replication of TgFGF2 calvarial osteoblasts was observed and primary cultures of bone marrow stromal cells from TgFGF2 expressed markers of mature osteoblasts but formed fewer mineralized nodules. The data presented indicate that non‐targeted over‐expression of FGF‐2 protein resulted in decreased endochondral and intramembranous bone formation. These results are consistent with FGF‐2 functioning as a negative regulator of postnatal bone growth and remodeling in this animal model. © 2005 Wiley‐Liss, Inc.
Spatio‐temporal organization of DNA replication in murine embryonic stem, primary, and immortalized cells
Authors: Panning Margaret M. , Gilbert David M.
Published: February 2005

The extent to which chromosomal domains are reorganized within the nucleus during differentiation is central to our understanding of how cells become committed to specific developmental lineages. Spatio‐temporal patterns of DNA replication are a reflection of this organization. Here, we demonstrate that the temporal order and relative duration of these replication patterns during S‐phase are similar in murine pluripotent embryonic stem (ES) cells, primary adult myoblasts, and an immortalized fibroblast line. The observed patterns were independent of fixation and denaturation techniques. Importantly, the same patterns were detected when fluorescent nucleotides were introduced into living cells, demonstrating their physiological relevance. These data suggest that heritable gene silencing during commitment to specific cell lineages is not mediated by global changes in the sub‐nuclear organization and replication timing of chromosome domains. © 2004 Wiley‐Liss, Inc.
Effect of low molecular weight heparin and different heparin molecular weight fractions on the activity of the matrix‐degrading enzyme aggrecanase: Structure–function relationship
Authors: Mousa Shaker A.
Published: February 2005

The matrix‐degrading enzyme aggrecanase has been identified in cartilage and is largely responsible for cartilage breakdown. The present study determined the efficacy of different heparin molecular weight fractions (HMWFs) and low molecular weight heparins (LMWHs) on aggrecanase activity. Aggrecanase activity was determined using biotinylated peptide substrate, which was immobilized onto streptavidin‐coated 96‐well plates; aggrecanase enzyme was then added. Proteolysis of the substrate at the specific amide bond was detected using specific antibody for the neoepitope generated. HMWFs ranging from 1,700 to 12,000 Da demonstrated a concentration‐dependent inhibitory efficacy of aggrecanase activity, with a Ki ranging from 5,000 nM down to 1 nM as a function of the molecular weight. The higher the molecular weight distribution, the greater the inhibitory efficacy of the heparin fragments toward aggrecanase activity. The absence or presence of antithrombin did not alter the affinity of heparin in inhibiting aggrecanase. Additionally, tissue factor pathway inhibitor at various levels did not alter the activity of aggrecanase. LMWHs demonstrated different levels of potency in inhibiting aggrecanase activity as a function of their average molecular weight distribution. Tinzaparin (average molecular weight = 6,500 Da) and enoxaparin (average molecular weight = 4,500 Da) demonstrated a Ki of 20 and 80 nM, respectively. The aggrecanase inhibitory effect of LMWH might contribute to blocking inflammation and tumor invasion by inhibiting aggrecanase activity and maintaining an intact extracellular matrix barrier. © 2005 Wiley‐Liss, Inc.
Attention deficit hyperactivity disorder in teens and adults: They don't all outgrow it
Authors: Resnick Robert J.
Published: February 2005

Attention deficit hyperactivity disorder (ADHD) has been long recognized and well established in children, but its continuation into adulthood has only recently been supported by the research. ADHD symptoms and concerns typically appear differently in adults, but treatment options, conceptually at least, are similar to those used for children who have ADHD. This article introduces the issue of Journal of Clinical Psychology: In Session devoted to ADHD in teens and adults. It presents the prevalence and manifestations of the disorder and then reviews the subsequent articles on the comorbidity, evaluation, education, psychopharmacology, and psychosocial treatments of ADHD for teens and adults. The issue concludes with an article on neurobiofeedback, a relatively new treatment option. © 2005 Wiley Periodicals, Inc. J Clin Psychol/In Session 61: 529–533, 2005.
ADHD couple and family relationships: Enhancing communication and understanding through Imago Relationship Therapy
Authors: Robbins Carol Ann
Published: February 2005

This article reviews the relationship deficits experienced by many individuals who have attention deficit hyperactivity disorder (ADHD) and proposes effective strategies, based on Imago Relationship Therapy (IRT), to assist them in communicating more effectively. The neurological underpinnings of the disorder often contribute to the development of poor social and communication skills and can lead to a lifetime of relationship difficulties. IRT, a brain‐based approach, is compatible with the neurological challenges of living with ADHD because it slows the communication process, provides structure, reduces reactivity, and helps individuals to be fully present so that their loved one can feel fully heard and understood. The couple's dialogue strengthens relationships by encouraging the development of stronger listening skills, better self‐control, and problem solving. Two case examples illustrate the clinical methods used. © 2005 Wiley Periodicals, Inc. J Clin Psychol/In Session 61: 565–577, 2005.
Comparison between three‐dimensional volume‐selective turbo spin‐echo imaging and two‐dimensional ultrasound for assessing carotid artery structure and function
Authors: Crowe Lindsey A. , Ariff Ben , Keegan Jennifer , Mohiaddin Raad H. , Yang Guang Zhong , Hughes Alun D. , McG. Thom Simon A. , Firmin David N.
Published: February 2005

Purpose

To compare a volume‐selective three‐dimensional turbo spin echo (TSE) technique with ultrasound (US) for assessing carotid artery wall structure and function.

Materials and Methods

A three‐dimensional volume‐selective TSE technique was used to image the carotid artery in 10 healthy subjects and five hypertensive subjects (each of whom were scanned three times while they received different hypertension treatments). Lumen and wall area were measured on MR images. Two‐dimensional US measurements of the intima‐media thickness (IMT) and lumen diameter were taken in three orientations through a single cross section. The lumen area change over the cardiac cycle was used to determine distension. For validation, a Bland‐Altman analysis was used to compare the vessel wall and lumen areas measured by three‐dimensional MRI volumes with those obtained by US scans.

Results

Agreement between the two methods was found. The mean difference in distension between US and MRI was 1.2% (±5.1%). For the wall area measurements, good agreement was shown, but there was a systematic difference due to the visualization of the adventitia by MRI. Both techniques offer an easy way to objectively measure lumen indices. MRI can provide the complete circumference over the length of a vessel, while US is flexible and relatively inexpensive. The application of US is limited, however, when subjects are poorly echogenic. A difference between hypertensive and healthy subjects was found.

Conclusion

There was a good agreement between MRI and the clinically established two‐dimensional US method. The MRI method has the advantage of providing increased vessel coverage, which permits one to assess localized abnormalities without assuming vessel uniformity. J. Magn. Reson. Imaging 2005;21:282–289. © 2005 Wiley‐Liss, Inc.
An automated algorithm for combining multivoxel MRS data acquired with phased‐array coils
Authors: Maril Nimrod , Lenkinski Robert E.
Published: February 2005

Purpose

To develop a fully automated algorithm for combining multivoxel magnetic resonance spectroscopy (MRS) data acquired with a phased‐array coil.

Materials and Methods

The frequency‐domain fitting method of LCModel (Provencher SW, Magn Reson Med 1993;30:672–679) was utilized to analyze the individual data sets. The phase corrections and the metabolite areas were then extracted from the LCModel output files for each individual spectrum. These areas were used to determine the dominant metabolite for each spatial location and to combine the individual spectra in a weighted manner.

Results

The combination of MRS data acquired from a phantom and the brains of normal volunteers with a four array coil yielded improved signal‐to‐noise ratio (SNR) in all voxels. The average improvement in SNR of the combined spectrum, as compared with the best of the individual spectra at each spatial location, was 1.4. In the phantom, the predicted SNR improvement of two‐fold was achieved at the center of the sample. In the brain, the maximum improvement was 1.8, due to sampling of the ventricles in the center of the sample.

Conclusion

The method described in this report provides a means for employing phased‐array coils in MRS with the same advantages as those found in MRI. J. Magn. Reson. Imaging 2005;21:317–322. © 2005 Wiley‐Liss, Inc.
The mechanism of ring enhancement in hepatocellular carcinoma on superparamagnetic iron oxide–enhanced T1‐weighted images: An investigation into peritumoral Kupffer cells
Authors: Tanimoto Akihiro , Wakabayashi Go , Shinmoto Hiroshi , Okuda Shigeo , Kuribayashi Sachio , Mukai Makio
Published: February 2005

Purpose

To investigate the mechanism of ring enhancement on ferumoxides‐enhanced T1‐weighted (T1W) gradient echo images in malignant focal hepatic lesions.

Materials and Methods

Eighteen patients with hepatocellular carcinoma (HCC) underwent breath‐hold T1‐, T2‐, and T2*‐weighted magnetic resonance (MR) images at 1.5‐Tesla after ferumoxides administration. The existence of ring enhancement on T1W, and the maximum size of the area showing decreased phagocytic activity on T2W and T2*W, and that of the area showing ring enhancement on T1W were evaluated. The Kupffer cell (KC) density of HCC itself and peritumoral liver parenchyma was assessed with KC stain sections.

Results

Ring enhancement was noted in 13 of 18 HCC (72%). Peritumoral KC density was increased in the ring enhancement (+) group as compared with the ring enhancement (−) group. In the ring enhancement (+) group, the tumor size measured on T2W was smaller than that measured on either T1W or T2*W, suggesting a sustained T1 relaxation effect and a decreased T2* relaxation effect in the peritumoral regions.

Conclusion

Ring enhancement on superparamagnetic iron oxide (SPIO)‐enhanced T1W may correlate with increased KC density and decreased SPIO clustering in KC in peritumoral regions. J. Magn. Reson. Imaging 2005;21:230–236. © 2005 Wiley‐Liss, Inc.
Multislice MR first‐pass myocardial perfusion imaging: Impact of the receiver coil array
Authors: Hoffmann Martin H.K. , Schmid Florian T. , Jeltsch Martin , Wunderlich Arthur , Duerk Jeffrey L. , Schmitz Bernd , Aschoff Andrik J.
Published: February 2005

Purpose

To compare a new 12‐element body phased‐array coil with a conventional four‐element surface receiver coil array to provide increased signal‐to‐noise ratios (SNRs) for cardiac steady state free precession (SSFP) perfusion imaging.

Materials and Methods

Thirteen consecutive patients were included in the study. Patients were examined both with a four‐element surface coil array and a 12‐element body coil array. First‐pass myocardial perfusion imaging using saturation recovery SSFP was acquired during antecubital injection of Gd‐DTPA. Imaging parameters: TR 2.8 msec/TE 1.3 msec, flip angle 50°, bandwidth 960 Hz/pixel and half‐Fourier acquisition. SNR was calculated using six regions of interest (ROI) for the myocardial perfusion scans. Calculations of corresponding ROIs using the two different coil setups were compared using analysis of variance (ANOVA). Semiquantitative perfusion parameters were calculated for both groups.

Results

The mean SNR in myocardial perfusion imaging increased by 21% using the 12‐element coil setup (P < 0.001) when compared to the four‐element coil. ROI comparisons revealed an increased signal inhomogeneity with the 12‐element coil when compared to four‐element coil experiments. Absolute normal range values of semiquantitative perfusion parameters were consistently higher using the 12‐element coil setup (P < 0.001).

Conclusion

The 12‐element coil array provides higher SNR, but these improvements come with trade‐offs in image homogeneity. Increased SNR translates into higher semiquantitative perfusion values and offers the potential for improved detection of perfusion defects. J. Magn. Reson. Imaging 2005;21:310–316. © 2005 Wiley‐Liss, Inc.
Can a single‐shot black‐blood T2‐weighted spin‐echo echo‐planar imaging sequence with sensitivity encoding replace the respiratory‐triggered turbo spin‐echo sequence for the liver? an optimization and feasibility study
Authors: Hussain Shahid M. , De Becker Jan , Hop Wim C.J. , Dwarkasing Soendersing , Wielopolski Piotr A.
Published: February 2005

Purpose

To optimize and assess the feasibility of a single‐shot black‐blood T2‐weighted spin‐echo echo‐planar imaging (SSBB‐EPI) sequence for MRI of the liver using sensitivity encoding (SENSE), and compare the results with those obtained with a T2‐weighted turbo spin‐echo (TSE) sequence.

Materials and Methods

Six volunteers and 16 patients were scanned at 1.5T (Philips Intera). In the volunteer study, we optimized the SSBB‐EPI sequence by interactively changing the parameters (i.e., the resolution, echo time (TE), diffusion weighting with low b‐values, and polarity of the phase‐encoding gradient) with regard to distortion, suppression of the blood signal, and sensitivity to motion. The influence of each change was assessed. The optimized SSBB‐EPI sequence was applied in patients (N = 16). A number of items, including the overall image quality (on a scale of 1–5), were used for graded evaluation. In addition, the signal‐to‐noise ratio (SNR) of the liver was calculated. Statistical analysis was carried out with the use of Wilcoxon's signed rank test for comparison of the SSBB‐EPI and TSE sequences, with P = 0.05 considered the limit for significance.

Results

The SSBB‐EPI sequence was improved by the following steps: 1) less frequency points than phase‐encoding steps, 2) a b‐factor of 20, and 3) a reversed polarity of the phase‐encoding gradient. In patients, the mean overall image quality score for the optimized SSBB‐EPI (3.5 (range: 1–4)) and TSE (3.6 (range: 3–4)), and the SNR of the liver on SSBB‐EPI (mean ± SD = 7.6 ± 4.0) and TSE (8.9 ± 4.6) were not significantly different (P > .05).

Conclusion

Optimized SSBB‐EPI with SENSE proved to be feasible in patients, and the overall image quality and SNR of the liver were comparable to those achieved with the standard respiratory‐triggered T2‐weighted TSE sequence. J. Magn. Reson. Imaging 2005;21:219–229. © 2005 Wiley‐Liss, Inc.
Late Holocene great earthquakes and relative sea‐level change at Kenai, southern Alaska
Authors: Hamilton Sarah , Shennan Ian
Published: February 2005

Kenai, located on the west coast of the Kenai Peninsula, Alaska, subsided during the great earthquake of AD 1964. Regional land subsidence is recorded within the estuarine stratigraphy as peat overlain by tidal silt and clay. Reconstructions using quantitative diatom transfer functions estimate co‐seismic subsidence (relative sea‐level rise) between 0.28±0.28 m and 0.70±0.28 m followed by rapid post‐seismic recovery. Stratigraphy records an earlier co‐seismic event as a second peat‐silt couplet, dated to ∼1500–1400 cal. yr BP with 1.14±0.28 m subsidence. Two decimetre‐scale relative sea‐level rises are more likely the result of glacio‐isostatic responses to late Holocene and Little Ice Age glacier expansions rather than to co‐seismic subsidence during great earthquakes.

Comparison with other sites around Cook Inlet, at Girdwood and Ocean View, helps in constructing regional patterns of land‐level change associated with three great earthquakes, AD 1964, ∼950–850 cal. yr BP and ∼1500–1400 cal. yr BP. Each earthquake has a different spatial pattern of co‐seismic subsidence which indicates that assessment of seismic hazard in southern Alaska requires an understanding of multiple great earthquakes, not only the most recent. All three earthquakes show a pre‐seismic phase of gradual land subsidence that marked the end of relative land uplift caused by inter‐seismic strain accumulation. Copyright © 2005 John Wiley & Sons, Ltd.
Nonlinear optical properties of Cr3+-doped lanthanum-magnesium
hexa-aluminate LaMgAl11O19
Authors: Manaa H
Published: February 2005

A single beam Z-Scan technique is used to characterize
the nonlinear optical properties of Cr3+-doped
lanthanum-magnesium hexa-aluminate LaMgAl11O19 with c.w.
laser radiation at 514.5 nm. The real part n'
2 = 2.6 ×
10-8 cm2/W and the imaginary part n''
2 = - 1.1 ×
10-9 cm2/W of the laser induced complex refractive index
are measured. The excited state absorption cross-section is
deduced and found to be 3×10-20 cm2 at the same
wavelength.
Measurements of Raman gain coefficient for barium tungstate crystal
Authors: Lisinetskii V A , Rozhok S V , Bus'ko D N , Chulkov R V , Grabtchikov A S , Orlovich V A , Basiev T T , Zverev P G
Published: February 2005

The Raman gain coefficient of a barium tungstate
crystal was measured in the 532 nm to 1064 nm spectral region. The
experimentally obtained data were fitted with the empirical
equation, which takes into account the resonance electronic
transitions.
Two Methods to Generate Multiple Compositions in Combinatorial Ink‐Jet Printing of Ceramics
Authors: Wang Jian , Mohebi Mohammad Masoud , Evans Julian R. G.
Published: February 2005

Summary:Combinatorial exploration of material compositions and associated informatics having influenced medicinal chemistry are now transforming the material sciences. In ceramic science, both thin and thick film combinatorial techniques are available. Ink‐jet printing provides a pathway to the latter. Mixing behind the nozzle and in front of the nozzle in well plates is described here. Such instruments are described and compared, and compositional calibration details for both are given.

Calibration library printed from a ceramic ternary system.

magnified image

Calibration library printed from a ceramic ternary system.
Cover Picture: Macromol. Rapid Commun. 4/2005
Authors: Tekin Emine , Holder Elisabeth , Marin Veronica , de Gans Berend‐Jan , Schubert Ulrich S.
Published: February 2005

Cover: The cover shows various aspects of ink‐jet printing of polymers: a thickness library of films of electroluminescent polymer, ink‐jet printing polymers on a MALDI target and a chainlike structure that remains after ink‐jet printing a line of polymer‐containing droplets. The foreground shows an ejected droplet of butylacetate with various satellite droplets.

Further details can be found in the Communication by E. Tekin, E. Holder, V. Marin, B.‐J. de Gans, and U. S. Schubert* on page 293.
Spatial characterization of T1 and T2 relaxation times and the water apparent diffusion coefficient in rabbit Achilles tendon subjected to tensile loading
Authors: Wellen J. , Helmer K. G. , Grigg P. , Sotak C. H.
Published: February 2005

Tendons exhibit viscoelastic mechanical behavior under tensile loading. The elasticity arises from the collagen chains that form fibrils, while the viscous response arises from the interaction of the water with the solid matrix. Therefore, an understanding of the behavior of water in response to the application of a load is crucial to the understanding of the origin of the viscous response. Three‐dimensional MRI mapping of rabbit Achilles tendons was performed at 2.0 T to characterize the response of T1 and T2 relaxation times and the apparent diffusion coefficient (ADC) of water to tensile loading. The ADC was measured in directions both parallel (ADC∥) and perpendicular (ADC⟂) to the long axis of the tendon. At a short diffusion time (5.8 ms) MR parameter maps showed the existence of two regions, here termed “core” and “rim”, that exhibited statistically significant differences in T1, T2, and ADC⟂ under the baseline loading condition. MR parameter maps were also generated at a second loading condition of ∼1 MPa. At a diffusion time of 5.8 ms, there was a statistically significant increase in the rim region for both ADC⟂ (57.5%) and ADC∥ (20.5%) upon tensile loading. The changes in core ADC(⟂, ∥), as well as the relaxation parameters in both core and rim regions, were not statistically significant. The effect of diffusion time on the ADC(⟂, ∥) values was investigated by creating maps at three additional diffusion times (50.0, 125.0, 250.0 ms) using a diffusion‐weighted, stimulated‐echo (DW‐STE) pulse sequence. At longer diffusion times, ADC(⟂, ∥) values increased rather than approaching a constant value. This observation was attributed to T1 spin‐editing during the DW‐STE pulse sequence, which resulted in the loss of short‐T1 components (with correspondingly lower ADCs) at longer diffusion times (corroborating the results from earlier spectroscopic work). The T1 spin‐editing effect was observed both in the core and in the rim regions of the tendon and hence was not solely due to the redistribution of water from the core to the rim upon loading. A measure reflective of the regional change in proton density was noted to be consistent with tensile‐load‐induced water transport from the central to the peripheral tendon region. Magn Reson Med 53:535–544, 2005. © 2005 Wiley‐Liss, Inc.
k‐space undersampling in PROPELLER imaging
Authors: Arfanakis Konstantinos , Tamhane Ashish A. , Pipe James G. , Anastasio Mark A.
Published: February 2005

PROPELLER MRI (periodically rotated overlapping parallel lines with enhanced reconstruction) provides images with significantly fewer B0‐related artifacts than echo‐planar imaging (EPI), as well as reduced sensitivity to motion compared to conventional multiple‐shot fast spin‐echo (FSE). However, the minimum imaging time in PROPELLER is markedly longer than in EPI and 50% longer than in conventional multiple‐shot FSE. Often in MRI, imaging time is reduced by undersampling k‐space. In the present study, the effects of undersampling on PROPELLER images were evaluated using simulated and in vivo data sets. Undersampling using PROPELLER patterns with reduced number of samples per line, number of lines per blade, or number of blades per acquisition, while maintaining the same k‐space field of view (FOVk) and uniform sampling at the edges of FOVk, reduced imaging time but led to severe image artifacts. In contrast, undersampling by means of removing whole blades from a PROPELLER sampling pattern that sufficiently samples k‐space produced only minimal image artifacts, mainly manifested as blurring in directions parallel to the blades removed, even when reducing imaging time by as much as 50%. Finally, undersampling using asymmetric blades and taking advantage of Hermitian symmetries to fill‐in the missing data significantly reduced imaging time without causing image artifacts. Magn Reson Med 53:675–683, 2005. © 2005 Wiley‐Liss, Inc.
Noninvasive in vivo MRI detection of neuritic plaques associated with iron in APP[V717I] transgenic mice, a model for Alzheimer's disease
Authors: Vanhoutte G. , Dewachter I. , Borghgraef P. , Van Leuven F. , Van der Linden A.
Published: February 2005

Transgenic mice overexpressing the London mutant of human amyloid precursor protein (APP[V717I]) in neurons develop amyloid plaques in the brain, thus demonstrating the most prominent neuropathological hallmark of Alzheimer's disease. In vivo 3D T2*‐weighted MRI on these mice (24 months of age) revealed hypointense brain inclusions that affected the thalamus almost exclusively. Upon correlating these MRI observations with a panel of different histologic staining techniques, it appeared that only plaques that were positive for both thioflavin‐S and iron were visible on the MR images. Numerous thioflavin‐S‐positive plaques in the cortex that did not display iron staining remained invisible to MRI. The in vivo detection of amyloid plaques in this mouse model, using the intrinsic MRI contrast arising from the iron associated with the plaques, creates an unexpected opportunity for the noninvasive investigation of the longitudinal development of the plaques in the same animal. Thus, this work provides further research opportunities for analyzing younger APP[V717I] mouse models with the knowledge of the final outcome at 24 months of age. Magn Reson Med 53:607–613, 2005. © 2005 Wiley‐Liss, Inc.
Macroscopic orientation component analysis of brain white matter and thalamus based on diffusion tensor imaging
Authors: Wakana Setsu , Nagae‐Poetscher Lidia M. , Jiang Hangyi , van Zijl Peter , Golay Xavier , Mori Susumu
Published: February 2005

Diffusion tensor imaging (DTI) can delineate white matter architecture based on fiber orientation. The purpose of this paper is to use the orientation information contained in DTI to study axonal organization of the brain both macroscopically and quantitatively. After performing gray/white matter segmentation using a fractional anisotropy threshold, the white matter can be further decomposed into components composed of tracts oriented along three orthogonal anatomic axes (right–left, superior–inferior, and anterior–posterior). For each component, the volume and MR parameters were quantified. To characterize the axonal architecture of the brain, this technique was applied to the entire brain using a Talairach‐based brain parcellation method and to the thalamus by manual segmentation. Reproducibility of this analysis tool was examined by repeating the measurements in the same subject, and individual differences were appreciated from the data acquired in 11 healthy volunteers. Based on the results from these preliminary data sets, this new analysis technique is expected to be an effective tool for macroscopic white matter characterization. Magn Reson Med 53:649–657, 2005. © 2005 Wiley‐Liss, Inc.
Characterization of intervertebral disc degeneration by high‐resolution magic angle spinning (HR‐MAS) spectroscopy
Authors: Keshari Kayvan R. , Zektzer Andrew S. , Swanson Mark G. , Majumdar Sharmila , Lotz Jeffrey C. , Kurhanewicz John
Published: February 2005

The goal of this study was to determine the ability of high‐resolution magic angle spinning (HR‐MAS) NMR spectroscopy to distinguish different stages of intervertebral disc degeneration (IVDD). 17 discs were removed from human cadavers and analyzed them using 1D and 2D (total correlation spectroscopy (TOCSY)) 1H HR‐MAS spectroscopy, and T1 and T2 relaxation time measurements to determine the chemical composition and changes in chemical environment of discs with increasing levels of degeneration (Thompson grade). Among the significant findings were that spectra were very similar for samples taken from annular and nuclear regions of discs, and that visually apparent changes were observed in the spectra of the annular and nuclear samples from discs with increasing Thompson grade. Area ratios of the N‐acetyl to choline (Cho) regions, and Cho to carbohydrate (Carb) regions of the spectra allowed us to discriminate between discs of increasing Thompson grade with minimal overlap of individual ratios. Changes in T1 and T2 relaxation times of the chemical constituents of disc spectra were not significantly correlated to the degree of degeneration. The results of this study support the feasibility of using in vivo spectroscopy for detecting chemical changes associated with disc degeneration. Magn Reson Med 53:519–527, 2005. © 2005 Wiley‐Liss, Inc.
Oxygen‐sensitive contrast in blood for steady‐state free precession imaging
Authors: Dharmakumar Rohan , Hong Juimiin , Brittain Jean H. , Plewes Donald B. , Wright Graham A.
Published: February 2005

Steady‐state free precession (SSFP) methods have gained widespread recognition for their ability to provide fast scans at high signal‐to‐noise ratio. This paper demonstrates that such methods are also capable of reflecting functional information, particularly blood oxygenation state. It is well known that SSFP signals show substantial sensitivity to small off‐resonance frequency variations. However, that mechanism cannot explain the oxygen‐sensitive contrast in blood that was observed with steady‐state methods using phase‐cycled radiofrequency pulses. From theoretical and experimental models it is demonstrated that the mechanism responsible for such contrast originates from the motion of spins through local field inhomogeneities in and around deoxygenated red blood cells. In addition, this work shows that it is critical to choose the scan parameters carefully for robust oxygen‐sensitive contrast. Finally, it is demonstrated that it is possible to build a quantitative model that incorporates the Luz–Meiboom model, which had been used in the past to estimate quantitative measures of vascular blood oxygen levels. It is envisioned that this method could be instrumental in real‐time imaging focused on detecting diseases where the oxygen state of blood is impaired. Magn Reson Med 53:574–583, 2005. © 2005 Wiley‐Liss, Inc.
Free breathing 3D balanced FFE coronary magnetic resonance angiography with prolonged cardiac acquisition windows and intra‐RR motion correction
Authors: Stehning C. , Börnert P. , Nehrke K. , Dössel O.
Published: February 2005

A shortcoming of today's coronary magnetic resonance angiography (MRA) is its low total scan efficiency (<5%), as only small well‐defined fractions of the respiratory (50%) and cardiac (10%) cycle are used for data acquisition. These precautions are necessary to prevent blurring and artifacts related to respiratory and cardiac motion. Hence, scan times range from 4 to 9 min, which may not be tolerated by patients. To overcome this drawback, an ECG‐triggered, navigator‐gated free breathing radial 3D balanced FFE sequence with intra‐RR motion correction is investigated in this study. Scan efficiency is increased by using a long cardiac acquisition window during the RR interval. This allows the acquisition of a number of independent k‐space segments during each cardiac cycle. The intersegment motion is corrected using a self‐guided epicardial fat tracking procedure in a postprocessing step. Finally, combining the motion‐corrected segments forms a high‐resolution image. Experiments on healthy volunteers are presented to show the basic feasibility of this approach. Magn Reson Med 53:719–723, 2005. © 2005 Wiley‐Liss, Inc.
Extraction of overt verbal response from the acoustic noise in a functional magnetic resonance imaging scan by use of segmented active noise cancellation
Authors: Jung Kwan‐Jin , Prasad Parikshit , Qin Yulin , Anderson John R.
Published: February 2005

A method to extract the subject's overt verbal response from the obscuring acoustic noise in an fMRI scan is developed by applying active noise cancellation with a conventional MRI microphone. Since the EPI scanning and its accompanying acoustic noise in fMRI are repetitive, the acoustic noise in one time segment was used as a reference noise in suppressing the acoustic noise in subsequent segments. However, the acoustic noise from the scanner was affected by the subject's movements, so the reference noise was adaptively adjusted as the scanner's acoustic properties varied in time. This method was successfully applied to a cognitive fMRI experiment with overt verbal responses. Magn Reson Med 53:739–744, 2005. © 2005 Wiley‐Liss, Inc.
129Xe spectra from the heads of rats with and without ligation of the external carotid and pterygopalatine arteries
Authors: Nakamura Kazuhiro , Kondoh Yasushi , Wakai Atsushi , Kershaw Jeff , Wright David , Kanno Iwao
Published: February 2005

After rats inhaled hyperpolarized 129Xe gas, in vivo spectra from their heads revealed a dominant peak around 195 ppm, another easily resolvable peak near 189 ppm, a broad peak around 210 ppm, and two minor peaks around 198 ppm and 192 ppm. However, the source of each peak remains controversial. To further study the origin of each peak, we compared spectra obtained from the heads of normal rats with spectra taken from the heads of rats that had undergone ligation of the external carotid (ECA) and pterygopalatine (PPA) arteries, the major feeding vessels of nonbrain tissue in the rat head. The amplitude of the peak at around 189 ppm was greatly reduced in the ECA/PPA‐ligated rats, while the peak around 195 ppm persisted. We conclude that the signal that originates from the rat brain after inhalation of 129Xe gas is overwhelmingly dominated by the single resonance at 195 ppm. Magn Reson Med 53:528–534, 2005. © 2005 Wiley‐Liss, Inc.
Shutter‐speed analysis of contrast reagent bolus‐tracking data: Preliminary observations in benign and malignant breast disease
Authors: Li Xin , Huang Wei , Yankeelov Thomas E. , Tudorica Alina , Rooney William D. , Springer Charles S.
Published: February 2005

The standard pharmacokinetic model applied to contrast reagent (CR) bolus‐tracking (B‐T) MRI (dynamic‐contrast‐enhanced) data makes the intrinsic assumption that equilibrium transcytolemmal water molecule exchange is effectively infinitely fast. Theory and simulation have suggested that this assumption can lead to significant errors. Recent analyses of animal model experimental data have confirmed two predicted signature inadequacies: a specific temporal mismatch with the B‐T time‐course and a CR dose‐dependent underestimation of model parameters. The most parsimonious adjustment to account for this aspect leads to the “shutter‐speed” pharmacokinetic model. Application of the latter to the animal model data mostly eliminates the two signature inadequacies. Here, the standard and shutter‐speed models are applied to B‐T data obtained from routine human breast examinations. The signature standard model temporal mismatch is found for each of the three invasive ductal carcinoma (IDC) cases and for each of the three fibroadenoma (FA) cases studied. It is effectively eliminated by use of the shutter‐speed model. The size of the mismatch is considerably greater for the IDC lesions than for the FA lesions, causing the shutter‐speed model to exhibit improved discrimination of malignant IDC tumors from the benign FA lesions compared with the standard model. Furthermore, the shutter‐speed model clearly reveals focal “hot spots” of elevated CR perfusion/permeation present in only the malignant tumors. Magn Reson Med 53:724–729, 2005. © 2005 Wiley‐Liss, Inc.
SAVANT analysis of the microelectronics and photonics testbed solar cell data
Authors: Walters Robert J. , Summers G. P. , Messenger S. R. , Morton T. L.
Published: February 2005

An analysis of solar array data from the Microelectronic and Photonic Testbed (MPTB) space experiment is presented. The data are analyzed using the displacement damage dose (Dd) methodology developed by the US Naval Research Laboratory (NRL) as implemented in the Solar Array Verification and Analysis Tool (SAVANT). SAVANT is a WindowsTM‐based computer code that predicts the on‐orbit performance of a solar cell in a specified Earth orbit. The predicted solar cell performance produced by the SAVANT code are compared with the measured on‐orbit data. In addition, the calculated data are compared with onboard dosimeter measurements. The results allow both a validation of the SAVANT code and a comparison of the space environment models with measured on‐orbit data. The results show the models to match the measured data within a factor of 2. Published in 2005 by John Wiley & Sons, Ltd.
Moving past cultural homogeneity: Suggestions for comparisons of students' educational outcomes in the United States and China
Authors: Peverly Stephen T.
Published: February 2005

Based on observations of the Chinese educational system in the summer of 2002, I argue that comparisons of the performance of students in the United States and China, and by implication, of students in the United States and other East Asian countries, have been too homogeneous. I discuss four variables that could be included in future research between the United States and China (and by implication, in all U.S./East Asian research): urban versus rural education (SES), public versus private schools, China's ethnic minorities, and the education of boys and girls. Recommendations for future research are provided. © 2005 Wiley Periodicals, Inc. Psychol Schs 42: 241–249, 2005.
The coming‐of‐age of China's single‐child policy
Authors: Mcloughlin Caven S.
Published: February 2005

China's one‐child policy is now 25 years of age—the officially sanctioned age for marriage by men in the People's Republic of China. A significant proportion of those now about to enter their child‐bearing years are themselves the product of the first generation of one‐child homes. This article reviews the history of the single‐child policy, with specific regard to the forces that initiated it as a national imperative and which today appear to sustain its widespread acceptance by the Chinese peoples. This article considers the circumstances leading to the implementation of the single‐child policy, the development of incentives for compliance and penalties for noncompliance, information reflecting representative data‐based analyses of outcomes from the policy, and the present situation and scenarios that might lead to a revisitation of this policy. Impressions and data gathering were conducted through conversation with individuals from all social strata in six locales in the People's Republic of China and were contrasted with similar exploratory visits from 10 and 15 years ago. © 2005 Wiley Periodicals, Inc. Psychol Schs 42: 305–313, 2005.