bluuebunny/crossref_metadata_2025 huggingface dataset:
The impact of spatial resolution and respiratory motion on MR imaging of atherosclerotic plaque
Authors: Schär Michael , Kim Won Yong , Stuber Matthias , Boesiger Peter , Manning Warren J. , Botnar René M.
Published: April 2003

Purpose

To examine the impact of spatial resolution and respiratory motion on the ability to accurately measure atherosclerotic plaque burden and to visually identify atherosclerotic plaque composition.

Materials and Methods

Numerical simulations of the Bloch equations and vessel wall phantom studies were performed for different spatial resolutions by incrementally increasing the field of view. In addition, respiratory motion was simulated based on a measured physiologic breathing pattern.

Results

While a spatial resolution of ≥ 6 pixels across the wall does not result in significant errors, a resolution of ≤ 4 pixels across the wall leads to an overestimation of > 20%. Using a double‐inversion T2‐weighted turbo spin echo sequence, a resolution of 1 pixel across equally thick tissue layers (fibrous cap, lipid, smooth muscle) and a respiratory motion correction precision (gating window) of three times the thickness of the tissue layer allow for characterization of the different coronary wall components.

Conclusions

We found that measurements in low‐resolution black blood images tend to overestimate vessel wall area and underestimate lumen area. J. Magn. Reson. Imaging 2003;17:538–544. © 2003 Wiley‐Liss, Inc.
Time‐resolved contrast‐enhanced magnetic resonance angiography in pediatric patients using sensitivity encoding
Authors: Muthupillai Raja , Vick Giles W. , Flamm Scott D. , Chung Taylor
Published: April 2003

Purpose

To evaluate the role of time‐resolved contrast‐enhanced magnetic resonance angiography (CE‐MRA) using sensitivity encoding in imaging the thoraco‐abdominal vessels in pediatric patients.

Materials and Methods

Thoraco‐abdominal vessels of 22 pediatric patients (median age = 5 years) were evaluated with a 3D CE‐MRA technique in combination with SENSE following a 0.2 mmol/kg injection of Gd‐chelate. The acquisition parameters were as follows: TR/TE = 5/1.1 msec; flip angle = 40°; in‐plane phase encoding steps were reduced by a factor of 2 using sensitivity encoding (SENSE); 3D volume acquisition was repeated four to eight times consecutively during free breathing (four to eight dynamics) with a mean temporal resolution of 6.8 seconds/dynamic; and mean acquired voxel size = 1.4 × 1.7 × 3.1 mm (reconstructed as 1.4 × 1.4 × 1.55 mm). Arterial‐to‐venous signal intensity ratios (AVRs) were computed for each dynamic.

Results

All images were successfully reconstructed and were of diagnostic quality. The AVRs of prepeak, peak, and postpeak arterial volumes were 1.0 ± 0.5, 6.1 ± 3.3, and 1.3 ±0.9, respectively, indicating good arterial‐to‐venous separation. The signal‐to‐noise ratio (SNR) of the peak arterial volume was 41 ± 26.

Conclusion

Our results suggest that it is feasible to apply SENSE to a conventional 3D CE‐MRA technique in a time‐resolved fashion for imaging the thoraco‐abdominal vessels in pediatric patients during free breathing. J. Magn. Reson. Imaging 2003;17:559–564. © 2003 Wiley‐Liss, Inc.
Pair of resonant fiducial markers for localization of endovascular catheters at all catheter orientations
Authors: Kuehne Titus , Fahrig Rebecca , Butts Kim
Published: April 2003

Purpose

To test wireless resonance circuits (RC) to be used as fiducial marker of endovascular catheters during MR‐guided interventions. Current markers loose their signal enhancement for certain catheter orientations. The purpose of this study was to test a marker setup which overcomes this orientation problem.

Materials and Methods

The markers were constructed from a pair of two RCs. The RCs were individually tuned and the coil axes were oriented perpendicular to each other in order to decouple the two RCs. The markers were mounted on the tip of endovascular catheters and tested in vitro and in one porcine in vivo experiment.

Results

An intense MR signal at similar signal levels was noted at all catheter orientations. In the in vivo experiment the markers allowed for fast and reliable MR guidance of the catheters.

Conclusion

A pair of two individually tuned and decoupled RCs is well suited for MR guidance of endovascular catheters. J. Magn. Reson. Imaging 2003;17:620–624. © 2003 Wiley‐Liss, Inc.
Electrically Activated Poly(propylene)/Clay Nanocomposites
Authors: Kim Do Hoon , Park Jun Uk , Ahn Kyung Hyun , Lee Seung Jong
Published: April 2003

A novel approach to fabricate poly(propylene)/clay nanocomposites under an electric field without adding any compatibilizer was proposed. The electrically activated poly(propylene)/clay nanocomposites show enhanced rheological properties with the disappearance of the characteristic peak in X‐ray diffraction. Transmission electron microscopy was used to confirm the microstructural changes of the nanocomposites. Electric field was found to facilitate destruction of the layer‐stacking and separation of the silicate layers.

Time sweep results of poly(propylene)/clay composites before and after applying an electric field at 180 °C.

magnified image

Time sweep results of poly(propylene)/clay composites before and after applying an electric field at 180 °C.
Studies of Adsorption of Diblock Copolymers from Non‐Selective Solvent by Scheutjens‐Fleer Theory and Monte Carlo Simulation, 1
Authors: Chen Ting , Guo Lian , Liu Honglai , Hu Ying
Published: April 2003

Thorough investigations on the adsorption of diblock copolymers from a non‐selective solvent on solid surface have been performed by using Scheutjens‐Fleer mean‐field lattice theory. One main objective of this work is to make an in‐depth comparison between the Scheutjens‐Fleer theory (SF) and our previous simulation work. Although our study shows that there are some systematic deviations between theory and simulation, we still find that the calculations are in qualitative agreement with Monte Carlo (MC) simulation results. The theory can reproduce main features of diblock copolymer's adsorption as compared to the simulation. For instance, both theory and simulation correctly predict the appearance of a maximum in adsorption amount as a function of the adsorbing segment fraction in a chain when the total chain length is fixed. When the adsorption of diblock copolymer is relatively weak, the predictions made by the theory agree better with the simulation results. Being the first paper of a series, this article will focus on studying the adsorption information like segment density profiles, adsorption amount and isotherms, and adsorption layer thickness. The influence of adsorption energy, chain composition and bulk concentration on these adsorption properties was inspected by self‐consistent‐field theory and were further compared to MC simulation results. Also discussed are some other theoretical, simulation, and experimental results in the literature and their relationships with the conclusions derived from this work.

Adsorption amount versus chain composition f, M = 150, r = 50, box size is 50 × 50 × 50. $\bar \varepsilon _{{\rm Aa}} = 0.5$ (▵), 0.8 (⋄), 1.0 (•), 1.2 (○): MC results; line a, b, c, d: corresponding SF results.

magnified image

Adsorption amount versus chain composition f, M = 150, r = 50, box size is 50 × 50 × 50. $\bar \varepsilon _{{\rm Aa}} = 0.5$ (▵), 0.8 (⋄), 1.0 (•), 1.2 (○): MC results; line a, b, c, d: corresponding SF results.
Molecular mechanisms of G0/G1 cell‐cycle arrest and apoptosis induced by terfenadine in human cancer cells
Authors: Liu Jean‐Dean , Wang Ying‐Jan , Chen Chien‐Ho , Yu Cheng‐Fei , Chen Li‐Ching , Lin Jen‐Kun , Liang Yu‐Chih , Lin Shyr‐Yi , Ho Yuan‐Soon
Published: April 2003

Terfenadine (TF), a highly potent histamine H1 receptor antagonist, has been shown to exert no significant central nervous system side effects in clinically effective doses. In this study, we demonstrated that TF induced significant growth inhibition of human cancer cells, including Hep G2, HT 29, and COLO 205 cells, through induction of G0/G1 phase cell‐cycle arrest. The minimal dose of TF induced significant G0/G1 arrest in these cells was 1–3 μM. The protein levels of p53, p21/Cip1, and p27/Kip1 were significantly elevated, whereas the kinase activities of cyclin‐dependent kinase 2 (CDK2) and CDK4 were inhibited simultaneously in the TF‐treated cells. On the other hand, significant apoptosis, but not G0/G1 arrest, was induced in the HL 60 (p53‐null) or Hep 3B (with deleted p53) cells when treated with TF (3–5 μM). To clarify the roles of p21/Cip1 and p27/Kip1 protein expression, which was involved in G0/G1 arrest and apoptosis induced by TF in human cancer cells, antisense oligodeoxynucleotides (ODNs) specific to p21/Cip1 and p27/Kip1 were used, and the expression of the p21/Cip1 and p27/Kip1 were monitored by immunoblotting analysis. Our data demonstrated that the percentage of the apoptotic cells detected by annexin V/PI analysis in the TF‐treated group was clearly attenuated by pretreatment with p27/Kip1–specific ODNs. These results indicated that p27/Kip1 (but not p21/Cip1) protein indeed played a critical role in the TF‐induced apoptosis. We also demonstrated that the TF‐induced G0/G1 cell‐cycle arrest effect was not reversed by TF removal, and this growth inhibition lasted for at least 7 d. Importantly, the occurrence of apoptosis and cell growth arrest was not observed in the TF‐treated normal human fibroblast, even at a dose as high as 25 μM. Our study showed the molecular mechanisms for TF‐induced cell growth inhibition and the occurrence of apoptosis in human cancer cells. © 2003 Wiley‐Liss, Inc.
Isomer differentiation by combining gas chromatography, selective self‐ion/molecule reactions and tandem mass spectrometry in an ion trap mass spectrometer
Authors: Wu Hui‐Fen , Chuan Yu‐Jie
Published: April 2003

This study presents a novel, simple and rapid procedure for isomer differentiation by combining gas chromatography (GC), a selective self‐ion/molecule reaction (SSIMR) and tandem mass spectrometry (MS/MS) in an ion trap mass spectrometer (ITMS). SSIMR product ions were produced from four isomers. For aniline, SSIMR induces the formation of the molecular ion, [M+H]+, [M+CH]+, adduct ions of fragments ([M+F]+, where F represents fragment ions) and [2MH]+. 2 and 3‐Picoline produce [M+H]+, [2MH]+ and [M+F]+, while 5‐hexynenitrile produces [M+H]+, [M+F]+ and [2M+H]+ ions. The proposed method provides a relatively easy, rapid and efficient means of isomer differentiation via a SSIMR in the ITMS. Typically, isomer differentiation can be achieved within several minutes. The superiority of the SSIMR technique for isomer differentiation over electronic ionization (EI) is also demonstrated. Copyright © 2003 John Wiley & Sons, Ltd.
Simulation of the Asian summer monsoon in five European general circulation models
Authors: Martin G. M. , Arpe K. , Chauvin F. , Ferranti L. , Maynard K. , Polcher J. , Stephenson D. B. , Tschuck P.
Published: April 2003

A comparison is made of the mean monsoon climatology in five different general circulation models (GCMs) which have been used by the participants of a project, funded by the European Union, entitled Studies of the Influence, Hydrology and Variability of the Asian summer monsoon (SHIVA). The models differ considerably, in horizontal and vertical resolution, numerical schemes and physical parametrizations, so that it is impossible to isolate the cause of differences in their monsoon simulations. Instead, the purpose of this comparison is to document and compare the representation of the mean monsoon in models which are being used to investigate the characteristics of the monsoon, its variability and its response to different boundary forcings. All of the models produce a reasonable representation of the monsoon circulation, although there are regional variations in the magnitude and pattern of the flow at both 850 hPa and 200 hPa. Considerable differences between the models are seen in the amount and distribution of precipitation. The models all reproduce the basic monsoon seasonal variation, although the timing of the onset and retreat, and the maxima in the winds and precipitation during the established phase, differ between them. There are corresponding differences in the evolution of the atmospheric structure between the pre‐monsoon season and its established phase. It is hoped that this study will set in context the investigations of the monsoon system and its impacts carried out using these models, both during SHIVA and in the future. Copyright © 2000 Royal Meteorological Society.
Co-existence of different host-adapted forms of the Myzus persicae group (Hemiptera: Aphididae) in southern Italy
Authors: Margaritopoulos J.T. , Blackman R.L. , Tsitsipis J.A. , Sannino L.
Published: April 2003

Multivariate morphometric analysis (method of canonical variates) was used to compare 38 parthenogenetic lineages and three field collections of aphids of the Myzus persicae (Sulzer) group sampled on peach and tobacco in the Caserta region of southern Italy. Comparisons were also made with the morphology of lineages collected on peach in Lehonia, in central eastern Greece away from tobacco-growing regions, and on tobacco in Naphplion, in southern Greece. The lineages were measured after parthenogenetic rearing for one to three generations on the same host (potato) under constant conditions. As in previous work, the multivariate morphometric approach separated the aphids from peach from those feeding on tobacco. The life cycle category of the lineages was also examined. Almost all the lineages from peach in Caserta were holocyclic, yet the lineages from tobacco in the same region were unable to produce sexual morphs. The results suggest that tobacco-adapted and non-tobacco-adapted forms co-exist in the same region in southern Italy, not only because they colonize different host plants, but also because they have different life cycles. This is in complete contrast to the situation in peach-growing areas of northern Greece, and shows that the ecology and population structure of M. persicae is different in neighbouring counties of the Mediterranean area, even where climatic conditions and cultivated crops are similar.
Who belongs to ergonomics? An examination of the human factors community
Authors: Ahasan Rabiul , Imbeau Daniel
Published: April 2003

Examines the nature of the evolving practice of ergonomics and its aspirations to the status of profession. Identifies some of the confusions and tensions that prevent more coherent development and clear promotion of ergonomics.
Productivity tools: “horses for courses”
Authors: McKee David
Published: April 2003

With the rise of the generalist manager, and the demise of the productivity specialist, there has been a decline in the use of “standard” productivity tools and a move towards the application of “management systems”. This paper argues that the range of available productivity tools means that there is almost certainly a tool available for every productivity improvement situation. However, the paper points out that the deployment of such tools must be within a structured framework that manages the overall change process implicit in productivity improvement.
INTERLEAVED VERSUS A PRIORI EXPLORATION FOR REPEATED NAVIGATION IN A PARTIALLY-KNOWN GRAPH
Authors: ARGAMON-ENGELSON SHLOMO , KRAUS SARIT , SINA SIGALIT
Published: April 2003

In this paper, we address the tradeoff between exploration and exploitation for agents which need to learn more about the structure of their environment in order to perform more effectively. For example, a software agent operating on the World Wide Web may need to learn which sites on the net are most useful, and the most efficient routes to those sites. We compare exploration strategies for a repeated task, where the agent is given some particular task to perform some number of times. Tasks are modeled as navigation on a partially known (deterministic) graph. This paper describes a new utility-based exploration algorithm for repeated tasks which interleaves exploration with task performance. The method takes into account both the costs and the potential benefits (for future task repetitions) of different exploratory actions. Exploration is performed in a greedy fashion, with the locally optimal exploratory action performed during repetition of each task. We experimentally evaluated our utility-based interleaved exploration algorithm against a heuristic search algorithm for exploration before task performance (a priori exploration) as well as a randomized interleaved exploration algorithm. We found that for a single repeated task, utility-based interleaved exploration consistently outperforms the alternatives, unless the number of task repetitions is very high. In addition, we extended the algorithms for the case of multiple repeated tasks, where the agent has a different, randomly-chosen task (from a known subset of possible tasks) to perform each time. Here too, we found that utility-based interleaved exploration is clear in most cases.
The lectin jacalin induces phosphorylation of ERK and JNK in CD4+ T cells
Authors: Tamma Seetha M Lakshmi , Kalyanaraman V S , Pahwa Savita , Dominguez Paul , Modesto Ron R
Published: April 2003

The CD4 molecule plays an essential role in mediating the transduction of intracellular signals by functioning as a coreceptor for the complex T cell receptor/CD3 and also acts as the primary receptor for human immunodeficiency virus (HIV). Several authors have shown evidence that jacalin, a plant lectin, binds to CD4 and inhibits in vitro HIV infection. We analyzed jacalin-induced intracellular signaling events in CD4+ T cells and have shown that cell activation resulted in tyrosine phosphorylation of intracellular substrates p56lck, p59fyn, ZAP-70, p95 vav, phospholipase C-γ1, and ras activation, as assessed by conversion of ras guanosine 5′-diphosphate to ras guanosine 5′-triphosphate. We further examined extracellular regulated kinase (ERK) and c-jun NH2-terminal kinase (JNK) phosphorylation following stimulation with jacalin. The data indicate that the kinetics of JNK phosphorylation is delayed. Optimum phosphorylation of ERK2 was observed by 10 min, and that of JNK was observed by 30 min. Pretreatment with gp120 followed by stimulation with jacalin resulted in marked inhibition of all of the aforementioned intracellular events. The data presented here provide insight into the intracellular signaling events associated with the CD4 molecule–jacalin–gp120 interactions and HIV-induced CD4+ T cell anergy. Jacalin may be used as a possible tool for the study of CD4-mediated signal transduction and HIV-impaired CD4+ T cell activation.
Partially Hydrogenated 1,1′‐Binaphthyl as Ligand Scaffold in Metal‐Catalyzed Asymmetric Synthesis
Authors: Au‐Yeung Terry T.‐L. , Chan Shu‐Sun , Chan Albert S. C.
Published: April 2003

Although chiral binaphthyl‐type ligands are already known to be effective over a broad spectrum of reactions, they sometimes fail in providing high enantioselectivities in some catalytic asymmetric reactions. This article summarizes recent attempts to elevate their performance by partly hydrogenating the naphthyl components of the binaphthyl. The synthetic routes to some of these ligands are briefly outlined. Positive results are observed in asymmetric hydrogenation, alkylation, borane reduction, epoxidation and hetero‐Diels–Alder reactions. The function of the partially reduced binaphthyl skeleton, however, can sometimes be disadvantageous or ambiguous as illustrated in reactions such as asymmetric ring‐closing metathesis, 1,4‐conjugate addition, epoxidation, allylic alkylation, trimethylsilylcyanation, epoxide ring‐opening and hydroformylation.
Polymer‐Supported Bisacetoxybromate(I) Anion –‐An Efficient Co‐Oxidant in the TEMPO‐Mediated Oxidation of Primary and Secondary Alcohols
Authors: Brünjes Marco , Sourkouni‐Argirusi Georgia , Kirschning Andreas
Published: April 2003

A polymer‐bound reagent for the efficient oxidation of primary alcohols to aldehydes and secondary alcohols to ketones in the presence of a catalytic amount of 2,2,6,6‐tetramethyl‐1‐piperidinyloxyl (TEMPO) is described. The oxidation process is particular mild and allows one to prepare aldehydes with α‐chirality without racemization. This also includes the synthesis of α‐aminoaldehydes. In most cases, work‐up of this heavy metal‐free oxidation is achieved by simple filtration followed by removal of the solvent. Insight into the role of the bromate(I) anion in the oxidation process was gained from the TEMPO‐mediated oxidation of benzaldehyde in the presence of the hypochlorite anion loaded on an anion exchange resin.
Randomized comparison of the coil‐design Crossflex and the tubular NIR stent
Authors: Thuesen Leif , Andersen Henning R. , Krusell Lars R. , Bøtker Hans E. , Jørgensen Erik , Kelbæk Henning , Kristensen Steen D.
Published: April 2003

The purpose of this study was to compare the angiographic outcome of implantation of the coil‐design Crossflex stent with the tubular NIR stent for treatment of coronary artery stenoses. Two hundred twenty‐three patients with one genuine coronary artery lesion were randomized to implantation with a 15 mm Crossflex stent (n = 112) or a 16 mm NIR stent (n = 111). The patients had angiographic follow‐up after 6 months. Primary endpoint was minimal luminal diameter (MLD) after 6 months. There was a similar clinical outcome in the two groups. At 6‐month follow‐up, the MLD was significantly lower in the Crossflex group (1.94 ± 0.79 mm) than in the NIR group (2.37 ± 0.84 mm; P < 0.001). Early gain was the same in the two groups. Late loss and percent diameter stenoses were significantly higher in the Crossflex group. The binary restenoses rate was 26% and 17% in the Crossflex and the NIR groups, respectively (P = NS). The coil‐design Crossflex stent was found to be inferior to the tubular NIR stent concerning late loss and MLD at 6‐month follow‐up. Cathet Cardiovasc Intervent 2003;59:8–12. © 2003 Wiley‐Liss, Inc.
Endovascular closure of a large renal arteriovenous fistula
Authors: Rimon Uri , Garniek Alexander , Golan Gil , Schneiderman Jacob , Morag Benyamina
Published: April 2003

A case is described of a large renal arteriovenous fistula causing long‐term cardiovascular complications. Successful percutaneous embolization was achieved using temporary occlusion balloons, Guglielmi detachable coils, regular nondetachable spring coils, and cyanacrylate. The advanced therapeutic tools we used can improve the prognosis of patients with large and complicated arteriovenuos fistulas and prevent surgery. Cathet Cardiovasc Intervent 2003;59:66–70. © 2003 Wiley‐Liss, Inc.
Herstellung von Fettsäuremethylestern aus Rapsöl und Altfetten im diskontinuierlichen Betrieb
Authors: Dittmar T. , Dimmig T. , Ondruschka B. , Heyn B. , Haupt J. , Lauterbach M.
Published: April 2003

No abstracts.
Einfluss einer kontinuierlichen Prozessführung im Membranbioreaktor auf die Ferrichromproduktion von Ustilago maydis
Authors: Drews A. , Kraume M.
Published: April 2003

No abstracts.
A model for evaluating the effectiveness of CRM using the balanced scorecard
Authors: Kim Jonghyeok , Suh Euiho , Hwang Hyunseok
Published: April 2003

Customer relationship management (CRM) has become one of the leading business strategies in the new millennium. CRM is a broad term for managing business interactions with customers. The effectiveness of CRM can be measured as a satisfaction level achieved by CRM activities. Although CRM has emerged as a major business strategy for e-commerce, little research has been conducted in evaluating the effectiveness of CRM. Because it is difficult to demonstrate tangible returns on the resources expanded to plan, develop, implement, and operate CRM, the aim of our research is to measure the intangible attributes of these benefits, such as value enhancement, effectiveness, innovation, and service improvement. In this paper, we propose a customer-oriented evaluation model for evaluating the effectiveness of CRM and then illustrate the model through a case study.
A content analysis of mass media stories surrounding the consumer privacy issue 1990-2001
Authors: Roznowski JoAnn L.
Published: April 2003

The following study investigates mass media coverage of the consumer privacy issue from 1990–2001 across three media formats: newspapers, consumer magazines, and trade publications. The results indicate that media coverage has increased dramatically in all media formats. Overall, article content has varied relative to the primary privacy domain covered, primary story topic, and the portrayal of the direct marketing industry. Differences were found across media outlets with respect to the source of the privacy problem and the source of the potential solution. Implications and ideas for future research also are presented.
Regio‐ and Stereoselective Double Addition of Anionic C‐Nucleophiles to Cobalt‐Stabilized Acetylenedicarbaldehyde
Authors: Sui‐Seng Christine , Soleilhavoup Michèle , Maurette Luc , Tedeschi Christine , Donnadieu Bruno , Chauvin Remi
Published: April 2003

Though intrinsically unstable, Gorgues’ acetylenedicarbaldehyde is an appealing, highly functional C4 synthon, which can be stabilized by η2 complexation to a Co2(CO)6 unit. In contrast to the homologous dibenzoylacetylene complex, it can be used as a normal, doubly electrophilic, non‐conjugated γ‐dicarbonyl substrate toward alkyl‐, aryl‐, and alkynyllithium compounds or magnesium bromides; these anionic C‐nucleophiles do not predominantly attack at the metal‐carbonyl center. The 1,4‐dialkyl‐ and 1,4‐diphenylbut‐2‐yne‐1,4‐diol products are obtained with significant meso/dl diastereoselectivity (4−66% de), which can be explained by a simple model based on X‐ray diffraction data and MM calculations. The alkyl‐ and arylmagnesium bromide reactants are more selective than their lithium counterparts. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003)
Regioselective Spiroannulations of α‐Acetyl Lactones
Authors: Christoffers Jens , Oertling Heiko , Frey Wolfgang
Published: April 2003

Monocyclic spiroannulation precursors 3a−c were obtained by Michael reactions of α‐acetyl lactones 6a−c with methyl vinyl ketone (7). The selective formation of either regioisomer of both β‐oxo (5a−c) and δ‐oxo (4a−c) lactones from 3a−c was achieved by varying the reaction conditions. The δ‐oxo lactones 4a−c were obtained under basic (buffered) conditions in a pyrrolidine/AcOH system. Under acidic conditions, the annulation reaction afforded β‐oxo lactones 5a−c. Byproducts 8b,c were identified to be the decomposition products of β‐oxo lactones 5b and 5c by comparison with the spectra of the alcohols 10b,c derived directly from δ‐oxo lactones 4b and 4c by saponification/decarboxylation. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003)
The diagnostic utility of FLAIR imaging in clinically verified amyotrophic lateral sclerosis
Authors: Zhang Lijuan , Uluǧ Aziz M. , Zimmerman Robert D. , Lin Michael T. , Rubin Michael , Beal M. Flint
Published: April 2003

Purpose

To explore the overall diagnostic ability of magnetic resonance (MR) fluid‐attenuated inversion recovery (FLAIR) imaging for clinically verified amyotrophic lateral sclerosis (ALS).

Materials and Methods

Abnormal signal intensity in FLAIR images of 18 patients with ALS and 18 age‐matched normal controls were scored and compared. Six patients had serial MR imaging scans within 97 days. Mann Whitney U statistics and ANOVA were used for statistical analysis.

Results

Hyperintensity in the subcortical white matter (SWM) and the dark line along the posterior rim of the precentral gyri were found more frequently in patients with ALS. The scores for these two signs were significantly different from those of normal controls. Hyperintensity in the corticospinal tract (CST) was found in both ALS and normal controls, but the difference was not statistically significant. ANOVA on the serial FLAIR studies revealed no significant difference in the scores among the series. The hyperintensity in SWM had a sensitivity of 56% and specificity of 94%, while the dark line in the motor cortex had a 74% sensitivity and 67% specificity.

Conclusion

Hyperintensity in SWM and the dark line along the posterior rim of the precentral gyri appeared more frequently in the patients with ALS. SWM hyperintensity has a better specificity in association with clinically verified ALS, while the motor dark line has a better sensitivity. No correlation was found between the FLAIR findings and progression of the disease. J. Magn. Reson. Imaging 2003;17:521–527. © 2003 Wiley‐Liss, Inc.
The use of reflectometric test kits for estimating nitrification and soil invertase activity in the field
Authors: Gromes Reiner , Behrens Sandra , Nagel Elke
Published: April 2003

The objective of this study was to test the applicability of different reflectometric test kits for the determination of potential nitrification and the activity of invertase in soil directly in the field. For the investigation of nitrification in the field, the incubation time was reduced because a linear correlation between incubation time and nitrification rates was found. Likewise, a linear correlation between invertase activity and the incubation temperature was observed which allowed for the calculation of temperature‐dependent factors. Activity measurements in the field at lower temperatures in comparison to the standard procedure were corrected by these factors. Ten different soils were investigated for potential nitrification and invertase activity with standard methods in comparison to field tests with reflectometric detection of the reaction products. The results showed that the reflectometric test kits are suitable for the estimation of potential nitrification and invertase activity directly in the field.
Comparative Crystallization Study of Several Linear Dinitramines in Nitrocellulose‐Based Gels
Authors: Spitzer Denis , Braun Silke , Schäfer Michael Richard , Ciszek Fabrice
Published: April 2003

This study deals with the crystallization behaviour of several dinitramines with plasticizing abilities in a nitrocellulose‐based gel. The tendency of these compounds to interact with nitrocellulose is an important parameter for the development of new propellants, especially for those which should have a temperature‐independent combustion. It is shown that, on the basis of their crystallization behaviour, the nine studied dinitramines form three different groups. Whereas the first one (large symmetrical molecules) exhibits a strong crystallization tendency, the second group (asymmetric compounds) has low crystalline contents and shows a good interaction capacity with nitrocellulose. At last, DNDA6 (2,4‐dinitro‐2,4‐diazahexane) with 3.3 noncrystallizing molecules per anhydroglucosidic unit of nitrocellulose, presents the most pronounced interaction with nitrocellulose, due to its lowest content of crystalline plasticizer.
Classical Langevin dynamics for model Hamiltonians
Authors: Cohen Morrel H.
Published: April 2003

We propose a scheme for extending the model Hamiltonian method developed originally for studying the equilibrium properties of complex perovskite systems to include Langevin dynamics. The extension is based on Zwanzig's treatment of nonlinear generalized Langevin's equations. The parameters entering the equations of motion are to be determined by mapping from first‐principles calculations, as in the original model Hamiltonian method. The scheme makes possible, in principle, the study of the dynamics and kinetics of structural transformations inaccessible to the original model Hamiltonian method. Moreover, we show that the equilibrium properties are governed by an effective Hamiltonian which differs from that used in previous work by a term which captures the coherent part of the previously ignored dynamical interaction with the omitted degrees of freedom. We describe how the additional information required for the Langevin equations can be obtained by a minor extension of the previous mapping.
Calculation of Feynman diagrams in space and time by stationary phase
Authors: Gutzwiller M.
Published: April 2003

Feynman diagrams are usually derived in relativistic space and time, and then immediately converted into energy and momentum by a Fourier transform. A method is proposed that allows keeping the external vertices at fixed locations and finite times, while the internal vertices are integrated in space‐time as well. Propagators between the vertices are the well‐known Bessel functions of the relativistic distance. The example of the Compton effect is worked out.
Lattice effects in manganites
Authors: Iadonisi G. , Cataudella V. , De Filippis G. , Marigliano Ramaglia V. , Perroni C. A. , Ventriglia F.
Published: April 2003

The interplay of the electron–phonon interaction and of the double and super‐exchange magnetic effects in the La1–xCaxMnO3 perovskites with 0 < x < 0.5 is studied. It is shown that treating the electron–phonon interaction in a fully quantum manner in the intermediate electron–phonon coupling regime a charge density instability occurs near the metal–insulator transition, induced by either temperature or hole doping. Also the effects of the magnetic field and the oxygen isotope substitution on the phase diagram, the electron–phonon correlation function and the infrared absorption at x = 0.3 is studied. The lattice displacements show a strong correlation with the conductivity and the magnetic properties of the system. Finally the conductivity spectra are characterized by a marked sensitivity to the external parameters near the phase boundary.
Interplay between inelastic X‐ray scattering and ab initio density‐response calculations: Insight into the electronic correlations in aluminum
Authors: Tischler J. Z. , Larson B. C. , Zschack P. , Fleszar A. , Eguiluz A. G.
Published: April 2003

Inelastic X‐ray scattering (IXS) measurements on Al have been analyzed in conjunction with ab initio, time‐dependent density functional theory (TDDFT) calculations of the electron–hole excitation spectrum. The dynamical structure factor evaluated with use of the many‐body kernel fxc obtained within the adiabatic extension of the local‐density approximation (ALDA) is shown to be in good agreement with the IXS energy‐loss data for energies up to about 20 eV, for momentum transfers up to twice the Fermi wave vector. For larger energy transfers the complex, frequency‐dependent fxc obtained by Devreese and collaborators via dynamical‐exchange decoupling techniques is shown to lead to a description of the IXS data comparable with that of the ALDA. For low energies the ALDA works better, a conclusion with a simple physical interpretation. The analysis of the relative merits of the models for the many‐body interactions is made using IXS cross sections that were obtained in absolute units; to this end, a procedure was introduced which is applicable for arbitrary materials, not just for sp‐bonded Al.
Many‐body vacuum diagrams and their recursive graphical construction
Authors: Pelster A. , Glaum K.
Published: April 2003

The grand‐canonical potential of many‐body physics can be considered as a functional of the interaction‐free correlation function. As such it obeys a nonlinear functional differential equation which can be turned into a recursion relation. This is solved graphically order by order in the two‐particle interaction to find all connected vacuum diagrams with their proper weights. As a special case, the procedure is applied to generate the Hugenholtz diagrams for a weakly interacting Bose gas.
New approach to study melting processes in metal nanoparticles: capacitance measurements
Authors: Parravicini G. B. , Stella A. , Ungureanu M. C. , Merli P. G. , Migliori A. , Kofman R.
Published: April 2003

The size reduction of the nanosystems with respect to macroscopic samples (or also in the micrometric size range) necessarily implies a concomitant and substantial increase of the surface to volume ratio. The surface atoms often play a role in determining or affecting basic properties of the samples investigated. As a consequence, the quest for new techniques specialized to the study of the electrical, optical or thermodynamic behavior of the surfaces or interfaces is becoming progressively more important. By means of capacitance measurements on metallic (specifically Ga) nanoparticles, through the relationship between derivative of the dielectric constant with respect to the temperature and the contribution to entropy due to the applied electric field, we show that initial disorder starts to take place ≈65 K before full melting. The premelting region is characterized by two regimes, which will be briefly illustrated.
Festschrift in honour of Jozef T. Devreese
Authors: Brosens Fons , Fomin Vladimir , Lemmens Lucien , Peeters François
Published: April 2003

The present special issue of physica status solidi (b) is dedicated to Professor Dr. Jozef T. Devreese on the occasion of his 65th birthday. Professor Devreese from the Laboratory of Theoretical Physics of Solids at Antwerp University is a distinguished theoretical physicist with outstanding achievements in various areas of condensed matter physics over many decades. 40 contributions written by his colleagues, collaborators, and friends were assembled in this edition.

The cover picture of this Liber Amicorum shows an artist's view of the polaron, originally sketched by Jozef T. Devreese for the cover of Ref. [1].
Predicting Passive Intestinal Absorption Using A Single Parameter
Authors: Sanghvi Tapan , Ni Nina , Mayersohn Michael , Yalkowsky Samuel H.
Published: April 2003

A model is proposed for the prediction of either high or low fraction absorbed for an orally administered, passively transported drug on the basis of a new absorption parameter, Π. The model includes only two inputs: the octanol‐water partition coefficient (Kow) and the dimensionless oversaturation number (OLumen). The latter is the ratio of the concentration of drug delivered to the gastrointestinal (GI) fluid to the solubility of the drug in that environment. Thus, OLumen is equal to the dose‐normalized solubility for suspensions and unity for solutions. The value of Π increases with an increase in Kow and a decrease in OLumen for suspensions, and is equal to Kow for solutions.
A model and a general problem on plastic flow under large deformations
Authors: Litvinov W.G.
Published: April 2003

We introduce a constitutive equation of the plastic flow such that a medium is considered as a fluid, whose viscosity depends on the second invariant of the tensor of strains accumulated under a plastic flow and on the second invariant of the deviator of the stress tensor. For this constitutive equation a general problem on plastic flow under large deformations is formulated and studied. It is supposed that the surface forces acting on a body are defined in the form of a feedback such that the forces at a moment t depend on the shape of the body at this moment. The problem consists of finding the configuration of the deformed body at each moment of time, velocities, strains, and stresses. The general problem is approximated by problems with delay. We prove the existence and the uniqueness of a solution for the problems with delay. The solution of the original problem is obtained as a limit of the solutions of the problems with delay as the delay parameter tends to zero.
Wave propagation in a waveguide
Authors: Rawlins A.D. , Mahmood‐ul‐Hassan
Published: April 2003

We shall consider the sound radiation of a surface wave mode which propagates towards the mouth of a semi‐infinite waveguide which supports surface waves. This semi‐infinite waveguide is symmetrically located inside an infinite waveguide whose surface is lined with an absorbent surface. The whole system constitutes a new trifurcated waveguide boundary value problem. This model results in a scalar Wiener‐Hopf problem. An exact closed form solution is obtained with the aid of the Wiener‐Hopf technique. The theoretical problem solved has application in acoustics and electromagnetism.
A singular Homann differential equation
Authors: Agarwal R.P. , O'Regan D.
Published: April 2003

General existence criteria are presented for the boundary value problem y″ + qf(t, y, y′) = 0, 0 < t < 1, with ‐ay(0) + by′ (0) = c0 and y(1) = 0. Our nonlinearity f may be singular at y = 0.
Changes in lymphokine receptor expression and fatty acid composition of phospholipids and triacylglycerols in rat adipocytes associated with lymph nodes following a transient immune challenge
Authors: Priddle J.D. , Mattacks C.A. , Sadler D.A. , MacQueen H.A. , Pond C.M.
Published: April 2003

Single‐photon counting fluorimetry was used to record the time course of the expression of interleukin‐10 receptors labelled with fluorescent antibodies on the surface of adipocytes over 24 h, following an immune challenge to the rat popliteal lymph node. Homologous perinodal and remote‐from‐node samples from the stimulated and unstimulated popliteal depots were compared in rats fed on plain chow and chow supplemented with 10% w/w suet, fish or vegetable oils. Receptor expression was maximal 6 h after stimulation, and returned to baseline after 24 h, and was similar in the stimulated and unstimulated depots. Fewer receptors were elicited in tissues from rats fed lipid‐supplemented diets compared with the control diet, with fewest of all following the fish oil diet. These data suggest that interleukin‐10 is involved in local interactions between perinodal adipocytes and lymph node lymphoid cells. Both triacylglycerols and phospholipids contained more polyunsaturates and fewer saturates in perinodal adipose tissue than in samples from sites not associated with lymphoid tissue. These data are consistent with paracrine interactions between perinodal adipocytes and activated lymphoid cells.
NEW PRACTICES IN THE CULTIVATION OF THE MINT, MENTHA ARVENSIS IN THE INDO-GANGETIC PLAINS
Authors: SINGH A. K. , SRIVASTAVA R. K. , KALRA A. , BANSAL R. P. , TOMAR V. K. S. , BAHL J. R. , KUMAR S.
Published: April 2003

India is the world's dominant producer of crude Mentha arvensis oil, and exporter of its processed derivative, natural menthol. This status has been achieved through superior product price competitiveness resulting from progressive agronomic improvements that include a transition from cultivation of this mint as a semi-perennial to an annual crop. This paper describes and analyses recent developments in Indian M. arvensis cultivation.

Observations were made during 1998/99 and 1999/2000 in the fields of 295 farmers in the central Indo-Gangetic plains area. The criteria recorded included: mint cultivars used; the planting, weeding, irrigation, pesticide application and harvesting schedules; crop health in relation to diseases and pests; yields of the harvested herb and the distilled essential oil; the oil menthol content; and the net income.

Most of the farmers used the cultivar, Kosi. The performance and returns of Kosi transplanted in April had proved superior to Kosi and Shivalik suckers and to transplanted Shivalik. The returns from late-transplanted Kosi were in the range of Rupees (Rs) 25 000 to Rs 40 000 ha−1 (Rs 50≈US$1), similar to those from Kosi suckers and much higher than for both transplanted and suckers of Shivalik. This survey revealed that rotations of rice (Oryza sativa) with chickpea (Cicer arietinum) and mint, and pigeonpea (Cajanus cajan) with wheat (Triticum aestivum) and mint could be profitable in the central Indo-Gangetic plains. They also conserved inputs and were preferable to the conventional rice-wheat rotation. A re-survey in the summer of 2002 confirmed that recommendations made to farmers have led to the adoption of the Kosi and Himalaya cultivars in 80% of the survey region and that 70% of mint cultivation in the area occurs in the summer season.
Beyond Chesnaux: Workers, Class, and the Socialist Revolution in Modern China
Authors: Dirlik Arif
Published: April 2003

The history of urban labor in modern China is deeply entangled in questions of the communist revolution, and so are the interpretations of that history. If we leave out two important accounts of labor in Chinese written by organizers before the 1960s, studies of labor in modern China only have a four-decade history.
Recurrent brief depressive disorder reinvestigated: a community sample of adolescents and young adults
Authors: PEZAWAS L. , WITTCHEN H.-U. , PFISTER H. , ANGST J. , LIEB R. , KASPER S.
Published: April 2003

Background. This article presents prospective lower bound estimations of findings on prevalence, incidence, clinical correlates, severity markers, co-morbidity and course stability of threshold and subthreshold recurrent brief depressive disorder (RBD) and other mood disorders in a community sample of 3021 adolescents.

Method. Data were collected at baseline (age 14–17) and at two follow-up interviews within an observation period of 42 months. Diagnostic assessment was based on the Munich Composite International Diagnostic Interview (M-CIDI).

Results. Our data suggest that RBD is a prevalent (2·6%) clinical condition among depressive disorders (21·3%) being at least as prevalent as dysthymia (2·3%) in young adults over lifetime. Furthermore, RBD is associated with significant clinical impairment sharing many features with major depressive disorder (MDD). Suicide attempts were reported in 7·8% of RBD patients, which was similar to MDD (11·9%). However, other features, like gender distribution or co-morbidity patterns, differ essentially from MDD. Furthermore, the lifetime co-occurrence of MDD and RBD or combined depression represents a severe psychiatric condition.

Conclusions. This study provides further independent support for RBD as a clinically significant syndrome that could not be significantly explained as a prodrome or residual of major affective disorders.
Adolescent Self-Poisoning
Authors: Reith David M. , Whyte Ian , Carter Greg , McPherson Michelle
Published: April 2003

Abstract: Previous self-harm has been identified as a risk factor for subsequent suicide by adolescents. The objective of the study was to identify further risk factors for subsequent premature death and suicide in a population of adolescents presenting with self-poisoning. A longitudinal cohort design using data-linkage of consecutive adolescent patients presenting to the Hunter Area Toxicology Service, a regional toxicology service for Newcastle, Australia, with the National Death Index of the Australian Institute of Health and Welfare was used. A total of 441 adolescents aged 10 to 19 years presented with self-poisoning over 5 years from January 1991 to December 1995, with follow-up to March 2001. There were 14 deaths total, eight of which were likely suicides. There was a 22-fold increase in suicide rate for males and a 14-fold increase for females compared with age-normalized population rates. Adjusted hazard ratios (95% CI) for premature death were male gender 3.77 (1.11-12.78), nonaffective psychotic disorders 16.3 (3.83-69.34) and the mental illnesses of childhood 6.12 (1.68-22.23). There was a similar pattern for suicide: Male gender, nonaffective psychotic disorders, and the mental illnesses of childhood confer greater risk for subsequent suicide or premature death in this population.
Liver transplantation in association with hepatocellular carcinoma: An update of the international tumor registry
Authors: Molmenti Ernesto P. , Klintmalm Goran B.
Published: April 2003

Hepatocellular carcinoma is an epithelial tumor derived from hepatocytes that accounts for more than 80% of all primary hepatic tumors. The severity of the underlying disease is almost always the key factor in deciding whether to consider liver resection or transplantation as its treatment. Data in our registry corresponding to almost 800 patients from transplant centers throughout the world showed that patient survival after liver transplantation was significantly affected by histologic grade, tumor size >5 cm, and the presence of positive nodes. Recurrence-free survival showed a correlation with tumor size >5 cm, positive nodes, bilobar spread, and vascular invasion. At the present time, 59% of patients in our registry are alive, 84% of whom are free of tumor. Of those who died, half did so without evidence of tumor.