bluuebunny/crossref_metadata_2025 huggingface dataset:
Diversity, Stability, Recursivity, and Rule Generation in Biological System: Intra–Inter Dynamics Approach
Authors: Kaneko Kunihiko
Published: June 2003

Basic problems for the construction of a scenario for the life are discussed. To study the problems in terms of dynamical systems theory, a scheme of intra–inter dynamics is presented. It consists of internal dynamics of a unit, interaction among the units, and the dynamics to change the dynamics itself, for example by replication (and death) of units according to their internal states. Applying the dynamics to cell differentiation, isologous diversification theory is proposed. According to it, orbital instability leads to diversified cell behaviors first. At the next stage, several cell types are formed, first triggered by clustering of oscillations, and then as attracting states of internal dynamics stabilized by the cell-to-cell interaction. At the third stage, the differentiation is determined as a recursive state by cell division. At the last stage, hierarchical differentiation proceeds, with the emergence of stochastic rule for the differentiation to subgroups, where regulation of the probability for the differentiation provides the diversity and stability of cell society. Relevance of the theory to cell biology is discussed.
Emergence of Collective Behavior in Large Chaotic Dynamical Systems
Authors: Chaté Hugues
Published: June 2003

The possibilities for observing the emergence of collective behavior in large chaotic dynamical systems are discussed. Nontrivial collective behavior in extensively-chaotic situations is presented with the help of a few examples and argued to offer all the desirable properties of a truly generic phenomenon.
On a Direct Estimate of Densities of States and Partition Functions
Authors: Hashim R. , Romano S.
Published: June 2003

We report here an attempt of directly estimating densities of states, and hence partition functions, for classical lattice-spin models of a rather general type; the method has been applied to a few models in one dimension with nearest-neighbor interactions isotropic in spin space; their exact solutions, available in the literature, are used for unambiguous comparison. After obtaining the appropriate histograms, thermodynamic properties have been calculated over a range of temperatures. At sufficiently high temperatures, the resulting estimates are in very good agreement with available exact results; as expected, the agreement deteriorates at lower temperatures.
Lyapunov Instability in One-Dimensional Lennard-Jones System
Authors: Okabe Tsuneyasu , Yamada Hiroaki
Published: June 2003

We study a transition from quasiperiodic to stochastic motion in one-dimensional classical systems consisting of N particles with the nearest-neighbor Lennard–Jones interaction, extensively by computer simulation. We find a new feature in the change of the Lyapunov spectrum and the maximal Lyapunov exponent by changing its energy in the intermediate region between quasiperiodic and stochastic motions. The characteristics of the Lennard–Jones system in the intermediate region is considered by means of properties of Hessian matrix of potential function. The applicability of random matrix approximation for high energy region is also investigated, comparing with the case of soft-core potential.
Effective Dipole-Radiation-Field Theory: III. Three-Dimensional Oscillator
Authors: Dekker H.
Published: June 2003

The novel analysis of the interaction between a harmonically bound, nonrelativistic "isotropic point" charge and the electromagnetic field as presented in paper I [Int. J. Mod. Phys.B8, 2307 (1994)] and II [Int. J. Mod. Phys.B10, 1211 (1996)], is finally extended to the case of a three-dimensional oscillator. The coupling between the electron and the field is treated through all orders beyond the standard dipole model. After a statistical linearization of the highly nonlinear dynamics, the problem is solved exactly in terms of the system's normal modes. The procedure intrinsically involves a generalized mass renormalization. The solution is free of runaway modes. The quantum mechanical ultraviolet divergence known from the standard dipole model is shown to be suppressed by the generalized coupling. Inter alia an effective equation of motion for the charge is derived. It is also shown that the zero-coupling and the infinite-system limits do not commute.
Isotope-Shift Exponent and the Gap Ratio for d-Wave Pairing within the Phonon Mediated Mechanism
Authors: Sarkar Sujit , Das A. N.
Published: June 2003

An exact analytical expression for the isotope-shift exponent is derived for the d-wave pairing assuming a phonon-mediated interaction. The role of the orthorhombic distortion and second nearest-neighbor hopping on the transition temperature (T c ) and the isotope-shift exponent (α) are studied. The temperature dependence of the gap parameter and the doping dependence of the gap ratio are also investigated. It is found that introduction of second nearest-neighbor hopping increases T c ) as well as the gap ratio while decreases the minimum value of α. The variation of α with doping is qualitatively consistent with the experimental results of high-T c oxide systems.
Renormalization-Group Theory of Critical Phenomena in Confined Systems: Order-Parameter Distribution Function
Authors: Chen X. S. , Dohm V.
Published: June 2003

We present a renormalization-group study of the order-parameter distribution function near the critical point of O(n) symmetric three-dimensional (3D) systems in a finite geometry. The distribution function is calculated within the φ4 field theory for a 3D cube with periodic boundary conditions by means of a novel approach that appropriately deals with the Goldstone modes below T c . Results are given for both vanishing and finite external field h. The results describe finite-size effects near the critical point in the h– T-plane including the first-order transition at the coexistence line at h = 0 below T c . Quantitative theoretical predictions of the finite-size scaling function are presented for the Ising (n=1), XY(n=2) and Heisenberg (n=3) models. Good agreement is found with recent Monte Carlo data.
Renormalization-Group Analysis of Two-Dimensional Fluid Stirred by Random Force with Long-Range Correlations
Authors: Honkonen J.
Published: June 2003

Asymptotic behavior of the solution of the vorticity equation for two-dimensional randomly stirred fluid with long-range correlations of the driving force is analyzed with the aid of field-theoretic renormalization group. It is shown that a local term must be added to the correlation function of the random force for the correct renormalization of the model. This has been overlooked in the earlier work on this model, and the physical consequences of the renormalization-group analysis are re-examined in the framework of the renormalization procedure suggested.
Superuniversal Critical Behavior in Two-Dimensional Random Anisotropic Models with Discrete Symmetries
Authors: Jug G. , Shalaev B. N.
Published: June 2003

We study the critical behavior of two-dimensional (2D) anisotropic systems with weak quenched disorder described by the Ising model (IM) with random bonds, the dilute N-color Ashkin–Teller model (ATM) and some its generalizations. It is shown that all these models exhibit the same critical behavior as that of the 2D-IM apart from some logarithmic corrections. The minimal conformal field theory (CFT) models with randomness are found to be described by critical exponents which are numerically very close to those of the pure 2D-IM.
Exact Renormalization Group Approach in Scalar and Fermionic Theories
Authors: Kubyshin Yu.
Published: June 2003

The Polchinski version of the exact renormalization group equation is discussed and its applications in scalar and fermionic theories are reviewed. Relation between this approach and the standard renormalization group is studied, in particular the relation between the derivative expansion and the perturbation theory expansion is worked out in some detail.
Proteoglycan Alterations and Collagen Reorganisation in the Secondary Avian Cornea during Development
Authors: Connon Che J. , Siegler Veronique , Meek Keith M. , Hodson Stuart A. , Caterson Bruce , Kinoshita Shigeru , Quantock Andrew J.
Published: June 2003

Purpose: It is thought that proteoglycan (PG) alterations, collagen matrix reorganisation and the onset of corneal transparency in the developing avian cornea might be related events. The current histochemical study was designed to establish the character and distribution of corneal PG filaments in relation to collagen organisation during tissue morphogenesis. Methods: Corneas from days 13–18 developing chicken embryos were treated with cuprolinic blue (CuB) to examine sulphated PGs by transmission electron microscopy and quantitative image analysis. Results: On developmental day 13, corneas contained poorly defined lamellae and a large number of both small and large CuB-stained PG filaments, randomly distributed and often in collagen-free regions. By day 14 and after, the large CuB-stained PG filaments were much less abundant. At this time, too, collagen fibrils displayed an axial alignment and an occasional periodic arrangement of small CuB-stained PG filaments along their axes. By developmental day 15, lamellae were well formed and continued to increase in number and size thereafter. Between developmental days 16 and 17, there was a significant increase (p < 0.001) in the number of small, collagen-associated PG filaments. This increase persisted into day 18. Conclusions: The size, number and distribution of sulphated, CuB-stained PG filaments in the developing avian cornea change over time. This is particularly true between developmental days 13 and 14 and between days 16 and 17, concurrent with previously documented structural changes.
Colocalization of Tie2, Angiopoietin 2 and Vascular Endothelial Growth Factor in Fibrovascular Membrane from Patients with Retinopathy of Prematurity
Authors: Umeda Naoyasu , Ozaki Hiroaki , Hayashi Hideyuki , Miyajima-Uchida Hiroko , Oshima Kenji
Published: June 2003

Purpose: The tyrosine kinase receptor Tie2 and its ligands, the angiopoietins (Angs), play important roles in vascular integrity and neovascularization, modulating vascular endothelial growth factor (VEGF) activity. To elucidate the potential role of Angs and the Tie2 system in retinopathy of prematurity (ROP), we have investigated the expression of Angs, Tie2 and VEGF within fibroproliferative membranes in ROP. Methods: Fibroproliferative membranes were obtained from 38 cases with stage 5 ROP at the time of vitrectomy. Membranes were fixed in formalin and embedded in paraffin. Each specimen was serially sectioned for immunohistochemistry. Polyclonal antibodies specific for Ang1, Ang2, Tie2 and VEGF were used for immunostaining. Immunoreactivity for von Willebrand factor (factor VIII) was also assessed to confirm the identity of vascular endothelial cells. Results: Positive staining for Tie2 was observed in 23 of 38 specimens (60.5%). Tie2 was localized in vascularized regions of fibrovascular membranes and was co- expressed with VEGF and factor VIII. Ang2 stained positively in 18 of 38 (47.3%) serial sections where Tie2 was present, and was also co-expressed with VEGF and factor VIII. Ang1 was not generally observed in these specimens (3/38). Conclusions: VEGF and Ang2-Tie2 interactions may play an important role in the pathogenesis of ROP.
A novel approach using differential scanning calorimetry to investigate the dissolved state in aqueous solutions of polymers used for papermaking
Authors: Yamauchi Tatsuo , Tamai Nobutake
Published: June 2003

The size and conformations of dissolved polymer molecules of polyethylene glycol (PEG) in 5% aqueous solutions were examined through the use of differential scanning calorimetry (DSC). As long as the freezable bound water is considered to be the water enclosed by the entangled polymer chains in the solution, the appearance of the characteristics of a polymer begins to occur at a degree of polymerization (DP) between 11 and 21 and is largely completed at a DP of about 50. Assuming that the peak temperature of the DSC curve for the freezable bound water indicates the size of the entangled molecular coil, the lowering of the peak temperature with a decrease of molecular weight (MW) suggests a decrease in the size of the entangled molecular coil. The linear relationship between the peak temperature and the reciprocal of the number‐average MW suggests melting point depression as a plausible mechanism for the peak temperature lowering. Mixing of two polymers with different MWs—and thus, entangled molecular coils of different sizes—causes a kind of polymer–polymer interaction and the coil sizes change as follows. If the difference in the values of the two MWs is large, the sizes of the entangled molecular coil of each MW are brought closer to each other. The extent of approach is roughly proportional to the mixing ratio. If the difference in the values of the two MWs is not large, the original entangled molecular coils disappear and a single molecular coil of intermediate size appears instead. The size of the single intermediate molecular coil varies roughly according to the simple mixing law for the values of the two MWs. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 2798–2807, 2003
In‐building power lines as high‐speed communication channels: channel characterization and a test channel ensemble
Authors: Esmailian Tooraj , Kschischang Frank R. , Glenn Gulak P.
Published: June 2003

In‐building power lines have often been considered as attractive media for high‐speed data transmission, particularly for applications like home networking. In this paper, we develop models for power line channels based both on theoretical considerations and practical measurements. We consider power line channel frequency response and noise models in the 1–30 MHz band and propose a number of power line test channels in which to measure the performance of power line modems. Copyright © 2003 John Wiley & Sons, Ltd.
TNF‐α induces the generation of Langerin/(CD207)+ immature Langerhans‐type dendritic cells from both CD14–CD1a– and CD14+CD1a– precursors derived from CD34+ cord blood cells
Authors: Arrighi Jean‐François , Soulas Caroline , Hauser Conrad , Saeland Sem , Chapuis Bernard , Zubler Rudolf H. , Kindler Vincent
Published: June 2003

CD34+ cell‐derived hematopoietic precursors amplified with FLT3‐ligand, thrombopoietin and stem cell factor became, after a 6‐day induction with GM‐CSF, IL‐4 and TGF‐β1, HLA‐DR+, CD1a+, CD83–, CD86–, CD80– cells. A fraction of them expressed Langerin, Lag, and E‐cadherin, resembling epidermal Langerhans cells (LC). TNF‐α addedfor the last 3 days only marginally induced CD83 expression, but strikingly increased the proportion of immature Langerin+CD83– LC. Langerin+CD83+ and Langerin+CD83– cells were functionally distinct, the former internalizing less efficiently Langerin than the latter. Both CD1a–CD14– and CD1a–CD14+ cells sorted from FLT3‐ligand, thrombopoietin and stem cell factor cultures responded to TNF‐α by an increase of Langerin+ cells. Thus, TNF‐α rescued LC precursors irrespective of their commitment to the monocytic lineage. When added to GM‐CSF, IL‐4 and TGF β1 containing‐cultures, LPS or IL‐1β also induced significant numbers of Langerin+CD83– immature cells displaying a low allostimulatory activity, while CD40‐ligand largely promoted highly allostimulatory Langerin–CD83+ cells. Altogether, these data show that in contrast to CD40‐ligand, which induced LC maturation even in presence of TGF‐β1, nonspecific proinflammatory factors such as TNF‐α, IL‐1β or LPS, essentially induced immature LC generation, and little cell activation in the presence of TGF‐β1.
Effects of problem decomposition (partitioning) on the rate of convergence of parallel numerical algorithms
Authors: Cullum Jane K. , Johnson Keith , Tůma Miroslav
Published: June 2003

We focus on the interplay between the choice of partition (problem decomposition) and the corresponding rate of convergence of parallel numerical algorithms. Using a specific algorithm, for which the numerics depend upon the partition, we demonstrate that the rate of convergence can depend strongly on the choice of the partition. This dependence is shown to be a function of the algorithm and of the choice of problem. Information gleaned from tests using various 2‐way partitions leads to new partitions for which some degree of convergence robustness is exhibited. The incorporation of a known correction for approximate Schur complements into the original algorithm yields a modified parallel algorithm which numerical experiments indicate achieves robust convergence behaviour with respect to the choice of partition. We conclude that tests of a parallel algorithm which vary the method of partitioning can provide constructive information regarding the robustness of the algorithm and guidance for modifying the algorithm or the choice of partitioning algorithm to make the overall computations more robust. Copyright © 2003 John Wiley & Sons, Ltd.
Retrofitting implant overdenture attachments: A clinical report
Authors: Simon Harel
Published: June 2003

The remake of implant‐overdenture prostheses on preexisting implants can present the clinician with a challenge, especially when the prosthetic components used initially cannot be replaced. The difficulty of remaking the prosthesis may be further increased by implant attachments designed to be cemented to the implant itself—a feature that complicates future replacement. This clinical report describes the restoration of worn implant attachments using retrofit components.
A new removable implant analog
Authors: Rasetto Flavio H. , Driscoll Carl F.
Published: June 2003

A new implant analog system that improves the efficiency of the implant restoration's fabrication process is described. This 2‐piece analog contains an outer plastic sleeve that is retained within the stone cast. The inner portion, a metal analog, can be easily removed and replaced within the plastic sleeve. Because the metal analog is removable, the time‐consuming process of screwing and unscrewing the prosthesis‐ or abutment‐retaining screws during laboratory procedures can be minimized. The prosthesis can remain secured to the analog during waxing, metal finishing, and porcelain buildup, yet is easily removed from the cast for inspection.
Comparison of recordings obtained with computerized axiography and mechanical pantography at 2 time intervals
Authors: Petrie Cynthia S. , Woolsey Gerald D. , Williams Karen
Published: June 2003

Purpose The purpose of this study was to compare recordings of mandibular movements obtained with a Denar mechanical pantograph to those obtained with a Denar computerized axiograph (Cadiax compact).

Materials and Methods Pantographic recordings and computerized axiograms were collected on 10 subjects. All of the subjects had intact dentition and no clinical signs or symptoms of temporomandibular dysfunction. Tracings produced with the 2 instruments were compared using pantographic reproducibility indices (PRIs). Recordings with each instrument were repeated twice and assessed for consistency. Pearson's correlation coefficient was used to compare PRI scores obtained with the pantograph and the axiograph. Recordings with both instruments were repeated 2 weeks to 1 month later, and new PRI scores were calculated. Consistency between initial and second PRI scores for each instrument was assessed using a coefficient of stability.

Results The coefficients of stability between the initial and second recordings were r = 0.91 for mechanical pantography and r =−0.06 for computerized axiography. Comparison of recordings made by mechanical pantography and computerized axiography at the initial and second recordings showed poor concordance, with coefficients of 0.23 and −0.11, respectively.

Conclusions PRI scores recorded with the mechanical pantograph were consistent between the initial and second recordings. In contrast, recordings with the computerized axiograph appeared highly inconsistent across time. PRI scores calculated from the axiographs were significantly higher than PRI scores calculated from pantographic tracings for the same subject.
The Effect of Early Education on Patient Anxiety While Waiting for Elective Cardiac Catheterization
Authors: Harkness Karen , Morrow Lydia , Smith Kelly , Kiczula Michele , Arthur Heather M.
Published: June 2003

Background: A supply–demand mismatch with respect to cardiac catheterization (CATH) often results in patients experiencing waiting times that vary from a few weeks to several months. Long delays can impose both physical and psychological distress for patients. Purpose: The purpose of this study was to examine the effect of a psychoeducational nursing intervention at the beginning of the waiting period on patient anxiety during the waiting time for elective CATH. Methods: This was a 2-group randomized controlled trial. Intervention patients received a nurse-delivered, detailed information/education session within 2 weeks of being placed on the waiting list for elective CATH. Control group patients received usual care. Results: The mean waiting time for CATH was 13.4±7.2 weeks, which did not differ between groups ( P=0.509). Anxiety increased in both groups over the waiting time ( P=0.028). Health-related quality of life deteriorated over the waiting time in both groups ( P<0.05). On a visual analogue scale, there was a significant difference ( P=0.002) between the intervention (4.0±2.7) and control (5.2±3.0) groups in self-reported anxiety 2 weeks prior to CATH. Conclusions: The waiting period prior to elective CATH has a negative impact on patients’ perceived anxiety and quality of life and a simple intervention, provided at the beginning of the waiting period, may positively affect the experience of waiting.
Structural constraints on the spatial distribution of aftershocks
Authors: McCloskey John , Nalbant Süleyman S. , Steacy Sandy , Nostro Concetta , Scotti Oona , Baumont David
Published: June 2003

Calculations of static stress changes due to large earthquakes have shown that the spatial distribution of aftershocks is predictable to first order, with aftershocks primarily occurring in areas experiencing positive stress changes. Delineation of these areas relies on resolving the stress perturbation onto planes with known orientations; common practice is to use poorly constrained regional stress information to compute optimally oriented failure planes, assuming that they exist everywhere. Here we show that this assumption is not supported by observation but rather that aftershock failure planes are controlled by geological structure. We argue that useful aftershock hazard estimates are better made by replacing information on regional stress with statistical measures of structural orientations.
An aversive diet as thiamine‐free food blocks food‐induced release of excitatory amino acids in the accumbens
Authors: Monda M. , Viggiano A. , De Luca V.
Published: June 2003

Aims:  As the nucleus accumbens shell plays an important role in the control of eating behaviour, the aim of this study was to evaluate the changes in: (a) the level of aspartic and glutamic acids in the accumbens shell of conditioned rats after the presentation of an aversive diet containing thiamine‐free food; (b) the temperature of interscapular brown adipose tissue, effector of thermogenesis related to food intake.

Methods:  The concentration of aspartic and glutamic acids in the accumbens shell, and brown adipose tissue temperature were monitored in conditioned male Sprague–Dawley rats before and after the presentation of thiamine‐free food or standard laboratory food. The aspartic and glutamic acids were collected using a microdialysis probe and quantified by HPLC. Food intake was also measured.

Results:  The results indicated that an intake of standard laboratory food induced an increase in the level of aspartic and glutamic acids, and an elevation in temperature of brown adipose tissue; whereas an intake of thiamine‐free food blocks these increases in the conditioned animals.

Conclusion:  The thiamine‐free diet modifies the release of excitatory amino acids in the nucleus accumbens of conditioned animals. This diet also affects thermogenesis.
Endoscopic treatments for gastro‐oesophageal reflux disease
Authors: Vakil N. , Sharma P.
Published: June 2003

A number of endoscopic techniques have been described for the treatment of reflux disease. These include endoscopic plicators, which place submucosal or transmural sutures around the lower oesophageal sphincter, the Stretta procedure, which places minute areas of thermal injury in the muscle of the lower oesophageal sphincter and cardia, and injection techniques, in which inert substances are injected into the mucosa or the muscle of the lower oesophagus. The mechanism of action of these procedures has been studied to varying degrees. The Stretta procedure is the only endoscopic technique that has been shown to be effective in a sham‐controlled trial. Complication rates are generally low, but serious complications have been reported in some cases. The results with some of these techniques are promising, but all procedures described to date are limited by the absence of large, rigorously controlled trials against a form of treatment that has been proven to be both safe and effective (medical therapy). Future studies will need to use controls, validated outcome measures and pre‐determined end‐points and to provide comparative and long‐term data.
Oral beclometasone dipropionate in the treatment of extensive and left‐sided active ulcerative colitis: a multicentre randomised study
Authors: Campieri M. , Adamo S. , Valpiani D. , D'Arienzo A. , D'Albasio G. , Pitzalis M. , Cesari P. , Casetti T. , Castiglione G. N. , Rizzello F. , Manguso F. , Varoli G. , Gionchetti P.
Published: June 2003

Aim:  To explore the efficacy and safety of the topically acting steroid beclometasone dipropionate (BDP) in an oral controlled release formulation in the treatment of extensive or left‐sided ulcerative colitis.

Methods:  In a multicentre, randomised, parallel‐group, single‐blind study, patients with active mild to moderate ulcerative colitis were randomised to a 4‐week treatment with BDP 5 mg/day o.d. vs. 5‐ASA 0.8 g t.d.s. The primary efficacy variable was the decrease of Disease Activity Index (DAI) (clinical symptoms and endoscopic appearance of mucosa). Safety was evaluated by monitoring adverse events, vital signs, haematochemical parameters and adrenal function.

Results:  One hundred and seventy‐seven patients were enrolled and randomly treated with BDP (n = 90) or 5‐ASA (n = 87). Mean DAI score decreased in both treatments groups (P < 0.0001 vs. baseline for both groups). Clinical remission was achieved in 63.0% of patients in the BDP group vs. 62.5% in the 5‐ASA group. A significant DAI score improvement (P < 0.05) in favour of BDP was observed in patients with extensive disease. Both treatments were well tolerated. Mean plasma cortisol levels were significantly reduced vs. baseline in BDP recipients, but without signs of pituitary–adrenal function depletion.

Conclusion:  Oral BDP gave an overall treatment result in patients with active ulcerative colitis without signs of systemic side‐effects.
The impact of cropland cover on river nutrient levels in the Mississippi River Basin
Authors: Donner Simon
Published: June 2003

Aim This study developed high‐resolution datasets of the area of maize, soybean and wheat cultivation in the United States for 1950, 1970 and 1992. The datasets were used to examine the relationship between individual crop cover and nutrient levels in rivers across the Mississippi River Basin.

Location This study was conducted in the United States, with focus on the Mississippi River Basin.

Methods County and state‐level estimates of the planted area of maize, soybean and wheat were integrated with a satellite‐derived pattern in total cropland to develop 5′ × 5′ resolution datasets of the fractional area of maize, soybean and wheat in the United States for 1950, 1970 and 1992. Regression analysis was used to determine the relationships between mean levels of nitrogen, phosphorous and silica in 25 rivers across the Mississippi Basin, and the extent of maize, soybean and wheat cultivation in the watersheds.

Results The crop datasets provide a spatially explicit representation of the area of the three primary crops in 1950, 1970 and 1992. The datasets clearly depict the rapid expansion of soybean cultivation, the increased specialization of individual agricultural regions, and the accompanying reduction in agricultural biodiversity since 1950. The statistical analysis identified strong correlations between the extent of maize and soybean cover in a watershed and the level of nitrogen (N) and phosphorous (P) at the watershed outlet. In particular, the area of maize appears to be strongly related to the concentration of total‐N and the ratio of dissolved inorganic‐N and organic‐N at the watershed outlet.

Conclusions The intensification of cultivation of the three primary crops — maize, soybean and wheat — has altered land cover and water quality across the U.S. since 1950. The high present‐day rate of fertilizer use on maize and the expansion of soybean cultivation could be largely responsible for the change in nutrient ratios in the Mississippi River since 1950.
Extracorporeal Support for Patients with Hepatic Failure
Authors: Davenport Andrew
Published: June 2003

Extracorporeal support has been advocated for patients with acute and chronic liver failure. Patients with acute liver failure and those with decompensated cirrhosis can be broadly divided into two groups. The first group comprises those with acute liver failure and ongoing hepatic necrosis, and the second, those with long‐standing chronic decompensation admitted with one or more complications of liver failure, such as encephalopathy without any evidence of a precipitating factor or accompanying acute deterioration of liver function. This second group includes patients with acute liver failure, where the insult causing hepatic necrosis has been resolved, and those patients with chronic decompensation who suffer another insult to the liver, such as acute infection or variceal hemorrhage that causes further liver injury in the setting of multiorgan failure. These two groups are likely to have different outcomes and may need to be managed differently. In the first group, liver transplantation is the only possible long‐term therapeutic option, whereas in the second group, other possibilities such as extracorporeal liver support systems and/or medical therapy may allow these patients to return to their previous state before the acute insult. Over time extracorporeal support has expanded from simple peritoneal dialysis and hemodialysis, to the development of circuits designed primarily to remove both water and lipid‐soluble toxins and, in addition, bioartificial devices to provide replacement synthetic hepatic function.

Because many of the patients with an acute liver insult have ongoing chronic liver disease and develop hepatorenal syndrome, this group of patients has been targeted by several groups to study the role of liver support systems.
Serologic analysis of three cases of neonatal alloimmune thrombocytopenia associated with HLA antibodies
Authors: Saito Satoshi , Ota Masao , Komatsu Yumi , Ota Satoshi , Aoki Shigeru , Koike Kenichi , Tokunaga Izumi , Tsuno Takahisa , Tsuruta Goro , Kubo Tetsuo , Fukushima Hirofumi
Published: June 2003

BACKGROUND: Neonatal alloimmune thrombocytopenia (NAIT) is caused when maternal alloantibodies react with paternally inherited antigens present on the fetal PLTs, a reaction mainly due to antibodies against human PLT antigens. Cases in which NAIT has been caused by HLA antibodies are relatively rare. In this study, three cases of NAIT associated with HLA antibodies that occurred in a 1‐year period are reported.

STUDY DESIGN AND METHODS: The presence of HLA antibodies in these three NAIT case studies was elucidated by examining reactions of the neonatal and maternal sera with lymphocytes, PLTs, and beads from an HLA antibody screening test (FlowPRA, One Lambda Inc.). Absorption and elution tests with paternal cells were also conducted. In addition, the influence of titer and specificity of HLA antibodies on NAIT was analyzed in light of 24 other documented cases in Japan.

RESULTS: In the three case studies presented herein, antibodies against human PLT antigens were found in neither the maternal nor neonatal sera, while specific HLA antibodies were identified in both sera. Absorption of maternal serum with paternal PLTs eliminated the reactivity against paternal PLTs and lymphocytes.

CONCLUSION: Transplacental passage of maternal HLA antibodies was observed in the three neonates cited in the present study.
Monitoring of apheresis platelet bacterial contamination with an automated liquid culture system: a university experience
Authors: Brecher M.E. , Hay S.N. , Rothenberg S.J.
Published: June 2003

BACKGROUND: With 4 million platelet units transfused per year in the United States and with the current estimate of bacteria contamination rate in PLT units, it would be expected that 2000 to 4000 bacterially contaminated units are transfused and associated with 333 to 1000 cases of clinical sepsis.

STUDY DESIGN AND METHODS: Apheresis platelets were sampled on Day 2 of storage (collection day=Day 0) and issue (or following outdate, Days 6–8) using a sterile connection device (SCD) to attach a sampling bag. Using aseptic technique and a laminar flow hood, bottles were inoculated and placed onto an automated liquid culture system (BacT/ALERT 3D Microbial Detection System) for 7 days.

RESULTS: A total of 2397 apheresis PLT units were sampled. A triple apheresis collection was reactive within 14 hours of the Day 2 sampling (aerobic bottles) and the bags were removed from inventory. Staphylococcus epidermidis was identified in all three contaminated bags. Two double‐apheresis collections were found to be contaminated with Proprionibacterium sp. after 6 days of incubation but had been transfused to four patients without discernible clinical sequelae. There was one false‐positive aerobic bottle and one false‐positive anaerobic result due to inadvertent contamination of a bottle. Thus, the overall true‐positive rate was 7 of 2397 apheresis units (0.29%) with a true‐positive rate for aerobic organisms of 0.13% and an anaerobic true‐positive rate of 0.17%. The false‐positive rate was 2 out of 4794 samplings (0.04%) or 2 out of 9588 bottles (0.02%).

CONCLUSION: This preliminary data suggests that the use of a SCD, aseptic technique, and a laminar flow hood is associated with a low rate of contamination. In no case did an issue (or outdate) detect contamination that was not detected by the Day 2 culture. Additional surveillance is necessary before we can conclude that a Day 2 sterile culture is truly predictive of an issue (or outdate) sterile culture. Bacterial culture surveillance of PLTs would be expected to save lives and may facilitate an extension in PLT storage.
Focal segmental glomerulosclerosis in adults
Authors: Cameron J. Stewart
Published: June 2003

The lesion of focal segmental glomerulosclerosis (FSGS) presents even greater problems of definition, interpretation and treatment in adults than it does in children, to the point where the specificity and utility of the appearance can even be questioned. The histological diagnosis of FSGS in adults can be interpreted only if the clinical circumstances are known, but a group of nephrotic patients with FSGS can be separated from a much larger group of non-specific, probably secondary but similar lesions arising in many circumstances. This group appears even so to have a diverse aetiology, the majority being idiopathic, but a significant minority showing a family history and/or mutations in genes relating to several intracellular or surface podocyte proteins, as discussed in other articles in this symposium. This heterogeneity makes conclusions with regard to prognosis and treatment difficult to draw. Today, in contrast to 20 or even 10 years ago, it seems useful to treat all adult nephrotic patients with FSGS using an adequate course of corticosteroids lasting at least 4–6 months to establish whether they fall or not into the 20–30% who will respond to this treatment with decrease or loss of proteinuria. The prognosis of such responders (who may well suffer relapse) is relatively benign with regard to renal function, but the majority of the remainder evolve into renal failure. Their management remains a source of controversy in the absence of a proper database of randomized trials: more prolonged (up to 24 months) use of lower-dose corticosteroids with cyclosporine for 12 months or more has support from uncontrolled studies, but cyclophosphamide appears to be of less obvious benefit.
Trade‐off between information and computability: a technique for automated topological computations
Authors: Suuriniemi Saku , Kettunen Lauri
Published: June 2003

Finite element‐based PDE solver software systems are typically method‐driven. The user has to supply the data in a particular form required by a numerical method. The method refuses to start if the data is in incorrect format, and breaks down if correctly formatted data is insufficient or inconsistent. However, software can be made more flexible with data‐driven approach. The decisions on existence and uniqueness of the solution, as well as the choice of suitable computing methods are based on the data. This calls for a new stage of data processing for a solver, which is not essentially an expert system. The questions are formalizable and their solution must be based on efficient and robust computational techniques. We present an elementary computational technique for automatic treatment of topological problems arising from potential theory, boundary condition inspection, and coupled problems. The approach is based on computing Smith normal form of the non‐oriented boundary operator matrices, whose elements are from the ring N mod 2, i.e. only 0s and 1s, instead of the integers. This approach obviates the problems of excessive computation time and risk of overflow in integer computations.
Optimisation of magnetic sensors for current reconstruction
Authors: Formisano A. , Martone R.
Published: June 2003

The problem of reconstructing the current profile in regions not directly accessible by sensors is tackled, with reference to current profile reconstruction in cable in conduit conductors cable. A possible strategy for the choice of the optimal number, location and direction of magnetic probes measuring the field outside the source region is discussed. In addition, some considerations on the related inverse problem resolution are presented.
Hybrid magnetic equivalent circuit – finite element modelling of transformer fed electrical machines
Authors: Gyselinck J. , Dular P. , Legros W. , Grenier D.
Published: June 2003

This paper deals with the modelling of transformer supply in the two‐dimensional (2D) finite element (FE) simulation of rotating electrical machines. Three different transformer models are compared. The reference one is based on two 2D FE models, considering a cross‐section either parallel or perpendicular to the laminations of the magnetic core. The parameters of the two other transformer models, a magnetic equivalent circuit and an electrical equivalent circuit, can be derived from the reference model. Particular attention is paid to some common features of the transformer models, e.g. with regard to the inclusion of iron losses. The three models are used in the 2D FE simulation of the steady‐state load operation and the starting from stand‐still of an induction motor.
Multigrid for transient 3D eddy current analysis
Authors: Weiß Bernhard , Bíró Oszkár
Published: June 2003

A multigrid (MG) algorithm for the calculation of transient 3D eddy currents is presented. The finite element method with edge elements is used for the discretization of the problems. For the MG smoother, a multiplicative Schwarz algorithm and a special Gauss‐Seidel iteration are compared for different formulations of the eddy‐current problem. It appears that, using the right combination of smoother and eddy‐current formulation, the computation times can be substantially reduced.
Lung cancer in heavy equipment operators and truck drivers with diesel exhaust exposure in the construction industry
Authors: Järvholm B , Silverman D
Published: June 2003

Background:Several studies indicate that truck drivers have an increased risk of lung cancer, but few studies have examined lung cancer risk in heavy equipment operators. Workers in both occupations are exposed to diesel exhaust.

Aims:To examine the incidence and mortality from lung cancer among truck drivers and among drivers of heavy vehicles.

Methods:A computerised register of Swedish construction workers participating in health examinations between 1971 and 1992 was used. Male truck drivers (n = 6364) and drivers of heavy construction vehicles (n = 14 364) were selected as index groups; carpenters/electricians constituted the reference group (n = 119 984).

Results:Operators of heavy construction equipment experienced no increased risk of lung cancer compared to risk among the carpenter/electrician referents (61 casesv70.1 expected). However, a significant inverse trend risk with increasing use of cabins was apparent. Truck drivers had increased risks of cancer of the lung (61 casesv47.3 expected) and prostate (124 casesv99.7 expected), although only mortality for lung cancer was significantly increased. Comparisons with the general population showed similar results.

Conclusion:Results are consistent with those of previous studies suggesting that heavy equipment operators with potential exposure to diesel exhaust may have little or no increased risk of lung cancer, although the use of cabins seemed to decrease the risk of lung cancer. The results for truck drivers are also consistent with previous reports of increased lung cancer risk among truck drivers exposed to diesel exhaust, as well as recent reports linking diesel exhaust exposure to prostate cancer.
Cancer risk around the nuclear power plants of Trillo and Zorita (Spain)
Authors: Silva-Mato A , Viana D , Fernández-SanMartín M I , Cobos J , Viana M
Published: June 2003

Aim:To investigate the association between cancer risk and proximity of place of residence to the Guadalajara nuclear power plants: Trillo and Zorita.

Methods:Case-control study. Cases were patients admitted with cancer and controls were non-tumorous patients, both admitted to Guadalajara Hospital (period 1988–99). Exposure factor: place of residence (areas within 10, 20, and 30 km of each plant). Odds ratios (ORs) of those areas closest to the plants were calculated with respect to those furthest away; a linear trend analysis was also performed.

Results:In the extreme areas in the vicinity of Trillo, an OR of 1.71 was obtained (95% CI 1.15 to 2.53), increasing in magnitude in the subgroup of more radioinducible tumours and in the period considered as post-latency (1997–99). Risk increased linearly with proximity to the two plants, significantly in Trillo (p < 0.01) but not in Zorita (p = 0.19).

Conclusions:There is an association between proximity of residence to Trillo and cancer risk, although the limitations of the study should be kept in mind when interpreting the possible causal relation.
Universality of the Ultrathin Film Viscosity Law
Authors: Brodsky A.
Published: June 2003

An explanation of the remarkable singular behavior of the shear viscosity of ultrathin liquid films is presented. The "universal" viscosity law η eff ~ (|v|/d)-a originally observed by Hu, Carson and Granick [Phys. Rev. Letts.66, 2758 (1991)] is derived and the exponent a is found to be a = 1-δ-1 where δ is the critical exponent for a corresponding second order phase transition in the film. This exponent can take either the classical (mean field) value δ = 3, or other, nonclassical values depending on the universality class of the surface phase transition.
Cooper Instability for a Given Field in a Quiescent Fermi Gas
Authors: Malozovsky Y. M. , Fan J. D.
Published: June 2003

The Cooper instability in a Fermi gas is examined using the perturbative diagram approach. A graphical functional derivative technique based on Ward's identity is developed to obtain two-particle interactions and then to calculate the vertex part. The pairing instability for a given interaction, such as a phonon (plasmon, etc.) field, occurs in a quiescent Fermi sea, i.e. without exciting or involving background particles (holes), only if the interaction is attractive, as first proposed by Cooper and adopted in the BCS (Bardeen–Cooper–Schrieffer) theory. The consequence from this technique provides a way to evaluate the effect of the vertex corrections and responses of the Fermi gas in both charge and spin channels incorporating the backward scattering process. The significance of the methodology presented in the present work lies in the fact that it can both reproduce the known results, and, more importantly, be extended to investigate the intermediate or strong coupling case, such as nuclear interactions, where a neglect of vertex corrections may not be a good approximation.
Oscillatory Magneto-Conductance in Quantum Waveguides with Lateral Multi-Barrier Structures
Authors: Gu Ben-Yuan , Sheng Wei-Dong , Wang Jian
Published: June 2003

The magneto-transport properties of a narrow quantum waveguide with lateral multi-barrier modulation are investigated theoretically. It is found that the magneto-conductance as a function of Fermi energy or magnetic field exhibits square-wave-like oscillations. In the presence of magnetic field, the edge states are formed near each barrier and the boundaries. Therefore, the number of edge states increases with the number of lateral barriers, leading to the increase of the propagating modes. On the other hand, owing to the tunneling effect a pair of edge states around the barrier region with opposite moving directions may be coupled and formed a circulating localized state, leading to the quenching of the related propagating states. The resulting dispersion relation exhibits oscillation structures superimposed on the bulk Landau levels. These novel conductance characteristics may provide potential applications to the fabrication of new quantum devices.
Field Theory of Quantum Antiferromagnets: From the Triangular to the Kagome Lattice
Authors: Shubashree D. , Shankar R.
Published: June 2003

We analyse a family of models, that interpolates between the Triangular lattice antiferromagnet (TLAF) and the Kagome lattice antiferromagnet (KLAF). We identify the field theories governing the low energy, long wavelength physics of these models. Near the TLAF the low energy field theory is a nonlinear sigma model of a SO(3) group valued field. The SO(3) symmetry of the spin system is enhanced to a SO(3)R × SO(2)L symmetry in the field theory. Near the KLAF other modes become important and the field takes values in SO(3) × S2 . We analyse this field theory and show that it admits a novel phase in which the SO(3)R spin symmetry is unbroken and the SO(2)L symmetry is broken. We propose this as a possible mechanism by which a gapless excitation can exist in the KLAF without breaking the spin rotation symmetry.
Robustness of the Quantum Hall Effect, Sample Size Versus Sample Topology, and Quality Control Management of III–V Molecular Beam Epitaxy
Authors: Tscheuschner Ralf D. , Hoch Sascha , Leschinsky Eva , Meier Cedrik , Theis Sabine , Wieck Andreas D.
Published: June 2003

We measure the IQHE on macroscopic (1.5 cm × 1.5 cm) "quick and dirty" prepared III–V heterostructure samples with van der Pauw and modified Corbino geometries at 1.3 K. We compare our results with (i) data taken on smaller specimens, among them samples with a standard Hall bar geometry, (ii) results of our numerical analysis taking inhomogenities of the 2DEG into account. Our main finding is a confirmation of the expected robustness of the IQHE which favors the development of wide plateaux for small filling factors and very large samples sizes (here with areas 10 000 times larger than in standard arrangements).