bluuebunny/crossref_metadata_2025 huggingface dataset:
Mitigation of electromagnetic field radiated by PLC systems in indoor environment
Authors: Korovkin N. , Marthe E. , Rachidi F. , Selina E.
Published: June 2003

Power line communication (PLC) is a well‐known technique for data transmission over low‐voltage power lines. The PLC signals have frequency bandwidth of about 1–30 MHz and they may cause electromagnetic interferences with services operating in the same frequency range. The regulation of electromagnetic radiation from PLC signals is currently subject of investigation in various international standardization bodies.

This paper proposes a technique aiming at reducing the electromagnetic field radiated by indoor PLC signals, while not affecting the PLC signal itself. The basic idea is to take advantage of the additional ground conductor and inject a signal similar to the PLC signal into the ground–neutral line, but with a reversed phase. As a result, both the overall antenna mode‐ and transmission line mode‐currents are significantly reduced, as well as the radiated electromagnetic fields.

Experimental measurements are also carried out in a building and it is shown that the proposed technique allows for a significant reduction (up to 20 dB) of the PLC electromagnetic radiation in the considered frequency range (1–30 MHz). Copyright © 2003 John Wiley & Sons, Ltd.
HomePlug 1.0 powerline communication LANs—protocol description and performance results
Authors: Lee M. K. , Newman R. E. , Latchman H. A. , Katar S. , Yonge L.
Published: June 2003

Products implementing the HomePlug 1.0 standard allowing high‐speed communication on low‐voltage powerlines have recently started arriving on the U.S. market for home and office networking without the requirement for installing new wires. Effective use of the powerline bandwidth requires robust physical (PHY) and medium access control (MAC) protocols to mitigate the harsh conditions of the powerline channel as well as the capability to support prioritized multimedia traffic. This paper describes powerline communications and the HomePlug 1.0 protocol, based on orthogonal frequency division multiplexing (OFDM) and carrier sense multiple access with collision avoidance (CSMA/CA), along with its changes to allow prioritized channel access. It then presents performance results for the HomePlug 1.0 protocol using a simulation model, ideal laboratory measurements with actual HomePlug 1.0 devices and field tests in a residential building. Simulation and laboratory data rates were around 6 Mbps, and field tests gave rates from 1.6 to 5.3 Mbps at the application level. Copyright © 2003 John Wiley & Sons, Ltd.
Pre‐TCR signaling regulates IL‐7 receptor α expression promoting thymocyte survival at the transition from the double‐negative to double‐positive stage
Authors: Trigueros Cesar , Hozumi Katsuto , Silva‐Santos Bruno , Bruno Ludovica , Hayday Adrian C. , Owen Michael J. , Pennington Daniel J.
Published: June 2003

The pre‐T cell receptor (pre‐TCR) and IL‐7 receptor (IL‐7R) are critical mediators of survival, proliferation and differentiation in immature thymocytes. Here we show that pre‐TCR signaling directly maintains IL‐7Rα expression as developing thymocytes undergo β‐selection. Inhibition of IL‐7/IL‐7R signaling in (CD44–CD25–) DN4 cells results in decreased generation of double‐positive thymocytes due to increased death of rapidly proliferating β‐selected cells. Thus, we identify a mechanism by which pre‐TCR signaling controls the selective survival of TCRβ+ thymocytes, and define a further stage of T cell differentiation in which signaling from a TCR regulates the ability of that cell to respond to cytokine.
Three‐dimensional flow structure and channel change in an asymmetrical compound meander loop, Embarras River, Illinois
Authors: Frothingham Kelly M. , Rhoads Bruce L.
Published: June 2003

The planform dynamics of meandering rivers produce a complex array of meander forms, including elongated meander loops. Thus far, few studies have examined in detail the flow structure within meander loops and the relation of flow structure to patterns of planform change. This field‐based investigation examines relations between three‐dimensional fluid motion and channel change within an elongated, asymmetrical meander loop containing multiple pool–riffle structures. The downstream velocity field is characterized by a high‐velocity core that shifts slightly outward as flow moves through individual lobes of the loop. For some of the measured flows this core becomes submerged below the water surface downstream of the lobe apexes. Vectors of cross‐stream/vertical velocities indicate that skew‐induced helical motion develops within the pools near lobe apexes and decays over riffles where channel curvature is less pronounced. Maximum rates of bank retreat generally occur near lobe apexes where impingement of the flow on the outer channel bank is greatest. However, maximum rates and loci of bank retreat differ for upstream and downstream lobes of the loop, leading to increasing asymmetry of loop geometry over time—a finding consistent with experimental investigations of loop evolution. Copyright © 2003 John Wiley & Sons, Ltd.
Integrin targeting using RGD‐PEI conjugates for in vitro gene transfer
Authors: Kunath Klaus , Merdan Thomas , Hegener Oliver , Häberlein Hanns , Kissel Thomas
Published: June 2003

Background

Targeting to integrin receptor ανβ3 by RGD peptides seems to be a promising approach for gene delivery to proliferating endothelial cells of tumor metastases. PEGylation of cationic polymers offers a reduction of non‐specific binding to cell surfaces. However, little knowledge exists on the influence of charge shielding by PEGylation on targeted gene delivery. Therefore, a variety of RGD peptide‐polyethylenimine (PEI) conjugates with different degrees of substitution, with or without poly(ethylene glycol) (PEG) spacer, were synthesized. Influence of degree of substitution and PEG spacer on physicochemical properties as well as on integrin targeting of DNA/polymer complexes was evaluated.

Methods

The tetrapeptide RGDC was coupled to PEI with or without a PEG spacer. Complex formation with DNA was monitored by ethidium bromide (EtBr) fluorescence quenching. Hydrodynamic diameters of complexes and zeta‐potential were assessed using a Zetasizer. Fluorescence correlation spectroscopy (FCS) was used to determine peptide binding to living cells. Transfection efficiency was evaluated employing a luciferase reporter gene. Binding of complexes to Mewo cells was monitored by flow cytometry.

Results

Polyplexes of RGD‐PEI or RGD‐PEG‐PEI and DNA showed reduced quenching of EtBr fluorescence compared with PEI. All RGD conjugates formed small polyplexes (approximately 100 nm in diameter at a nitrogen/phosphate (N/P) ratio of 6.7). At N/P = 6.7, the zeta‐potentials of RGD‐PEI complexes were similar to PEI complexes (25–30 mV), while RGD‐PEG‐PEI formed neutral complexes. FCS showed saturable binding of RGD peptide to Mewo human melanoma cells and only low binding to A549 human lung carcinoma cells. A degree of substitution of 4.6% with SPDP as coupling reagent yielded a conjugate showing 50 times higher luciferase expression in Mewo cells than unmodified PEI at low N/P ratios around 3.3, while a degree of substitution of 1.6% only led to a moderately increased transfection efficiency. Flow cytometry experiments suggest that this effect is partly caused by increased attachment of complexes to cell surfaces. No improvement in transfection efficiency was found in ανβ3‐negative A549 cells. RGD‐PEG‐PEI complexes showed reasonable transfection efficiencies at high N/P ratios; however, no targeting effect could be found.

Conclusions

Coupling of the tetrapeptide RGDC without a PEG spacer improved transfection efficiency of PEI in integrin‐expressing Mewo cells by 1–2 orders of magnitude, especially at low N/P ratios. The use of a PEG spacer seems to impair targeting, possibly by not only shielding PEI, but also the RGD ligand. Copyright © 2003 John Wiley & Sons, Ltd.
Treatment of Epstein‐Barr virus‐associated hemophagocytic lymphohistiocytosis (EBV‐HLH) in young adults: A report from the HLH studyl center
Authors: Imashuku Shinsaku , Kuriyama Kikuko , Sakai Rika , Nakao Yoshitaka , Masuda Shin‐ichi , Yasuda Norimasa , Kawano Fumio , Yakushijin Kimikazu , Miyagawa Akiko , Nakao Taisei , Teramura Tomoko , Tabata Yasuhiro , Morimoto Akira , Hibi Shigeyoshi
Published: June 2003

Background

Epstein‐Barr virus‐associated hemophagocytic lymphohistiocytosis (EBV‐HLH), also known as EBV‐associated hemophagocytic syndrome, develops mostly in children and young adults and may be fatal. Early etoposide treatment has been confirmed to be effective in children. However, it is unclear whether the same treatment is useful in adults.

Procedure

To assess whether etoposide is effective in treating young adult cases, we retrospectively studied the therapeutic measures taken and outcomes in 20 young adult cases of EBV‐HLH. Eleven cases were registered in our HLH study center in Kyoto and nine derived from the literature. The patients were between 17 and 33 years old and eight were males. The influence of gender, cell lineage (T‐ or natural killer‐), EBV serology pattern, jaundice and treatment on the outcome was assessed.

Results and Conclusions

Patients receiving etoposide within four weeks after diagnosis had a good prognosis as five of the seven patients survived compared to one of 13 not treated with etoposide or treated late (chi‐square test for survival, P = 0.0095). The Kaplan–Meier analysis showed the 2.5‐year survival of 85.7 ± 13.2% in the early etoposide‐treated patients, compared to 10.3 ± 9.4% in the remaining patients (log‐rank test, P = 0.0141). Thus, early etoposide treatment is effective in treating EBV‐HLH in young adults as well as in children. Med Pediatr Oncol 2003;41:103–109. © 2003 Wiley‐Liss, Inc.
An iterated tangential filtering decomposition
Authors: Achdou Y. , Nataf F.
Published: June 2003

Large linear systems arising from the discretization of partial differential equations with finite differences or finite elements on structured grids in dimensiond(d⩾ 3) require efficient preconditioners. For a symmetric and positive definite (SPD) matrix, we propose a SPD block LDLTpreconditioner whose factorized form requires a smaller amount of memory than the original matrix. Moreover, the computing time for the preconditioner solves is linear with respect to the number of unknowns. The preconditioner is built indstages: in a first stage, we use the tangential filtering decomposition of Wittumet al. and obtain a preconditioner which remains rather difficult to factorize. Then, in a second stage, we apply tangential filtering decomposition recursively to the diagonal blocks of this first preconditioner. The final stage consists of factorizing exactly the blocks corresponding to one dimensional problems. Such preconditioners can also be computed adaptively and combined in a multiplicative way. A generic programming implementation is discussed and numerical tests are presented, in particular for problems with highly heterogeneous media. Copyright © 2003 John Wiley & Sons, Ltd.
Photoluminescence from self‐assembled GaAs inclusions embedded in a GaN host crystal
Authors: Andrianov A. V. , Novikov S. V. , Li T. , Xia R. , Bull S. , Harrison I. , Larkins E. C. , Foxon C. T.
Published: June 2003

We report on observation of photoluminescence in 1.2–1.4 eV spectral range from As‐doped GaN layers grown by plasma‐assisted molecular beam epitaxy. We attribute this emission to recombination in GaAs inclusions formed during the growth process in the GaN(As) layers. This near‐infrared emission is efficient under UV photoexcitation, but its intensity is low for excitation energies below the band gap of GaN. Low‐temperature photoluminescence spectra reveal a set of sharp emission lines with maxima from 1.516 eV to 1.436 eV. We attribute some of these sharp lines to the emission of excitons bound to nitrogen incorporated into the GaAs crystallites and also to their GaAs‐like optical phonon replicas. Photoluminescence excitation spectra show a series of maxima, which can be attributed to the formation of bound and free excitons and also to the formation of excitons with the simultaneous emission of GaAs‐like optical phonons.
Phytoremediation of dissolved phase organic compounds: Optimal site considerations relative to field case studies
Authors: Compton Harry R. , Prince George R. , Fredericks Scott C. , Gussman Christopher D.
Published: June 2003

The United States Environmental Protection Agency/Environmental Response Team (EPA/ERT) has
been supporting and implementing the use of phytoremediation to remediate dissolved phase organic compounds at
Superfund sites since March 1996. Since then, ERT has applied phytoremediation field plots, both pilot and full
scale, to a variety of field conditions. These active sites vary considerably as to depth to groundwater,
groundwater transmissivity, contaminant concentrations, contaminant hydrophobicity, climate, planting design,
plant selection, planting technique, and type of monitoring. Here we compare the literature and discuss lessons
learned at five Superfund sites. Current maintenance and monitoring techniques at these sites are also discussed
with recommendations for the maintenance and monitoring of similar sites in the future. © 2003 Wiley
Periodicals, Inc.
Hydrogenosome behavior during the cell cycle in Tritrichomonas foetus
Authors: Benchimol Marlene , Engelke Flávio
Published: June 2003

The hydrogenosome is an unusual organelle found in several trichomonad species and other protists living in oxygen poor or anoxic environments. The hydrogenosome behavior in the protist Tritrichomonas foetus, parasite of the urogenital tract of cattle, is reported here. The hydrogenosomes were followed by light and transmission electron microscopy during the whole cell cycle. Videomicroscopy, immunofluorescence microscopy, and immunocytochemistry were also used. It is shown that the hydrogenosomes divide at any phase of the cell cycle and that the organellar division is not synchronized. During the interphase the hydrogenosomes are distributed mainly along the axostyle and costa, and at the beginning of mitosis migrate to around the nucleus. Three forms of hydrogenosome division were seen: (1) segmentation, where elongated hydrogenosomes are further separated by external membranous profiles; (2) partition, where rounded hydrogenosomes, in a bulky form, are further separated by a membranous internal septum and, (3) a new dividing form: heart‐shaped hydrogenosomes, which gradually present a membrane invagination leading to the organelle division. The hydrogenosomes divide at any phase of the cell cycle. A necklace of intramembranous particles delimiting the outer hydrogenosomal membrane in the region of organelle division was observed by freeze‐etching. Similarities between hydrogenosomes and mitochondria behavior during the cell cycle are discussed.
The effects of abutment taper, length and cement type on resistance to dislodgement of cement‐retained, implant‐supported restorations
Authors: Bernal Guillermo , Okamura Mitsunobu , Muñoz Carlos A.
Published: June 2003

Purpose The purpose of this study was to compare the effect of 20 degrees and 30 degrees of total occlusal convergence (TOC), the occlusocervical dimension, and the type of cement on the tensile resistance to dislodgement of cement‐retained, implant‐supported restorations.

Materials and Methods Cylindrical preparations with TOC angles of 20 degrees and 30 degrees and occlusocervical dimensions of 4 mm (S) and 8 mm (L) were made through a machining process. The cylinders had a shoulder finish line of 1.0 mm in depth. Eight impressions were made of each machined cylinder and poured in type IV dental stone, for a total of 32 dies. Die spacer was applied to each die. A master wax pattern was designed, and the 32 wax patterns were marginated, invested, and cast in type IV gold alloy (n= 8). The gold crowns were cemented with Fleck's cement (zinc phosphate cement), Temp‐Bond (zinc oxide eugenol cement), Temp‐Bond plus Vaseline (30% by weight), and IMProv temporary cement (acrylic/urethane cement) under a 10‐kg load and placed in a humidor at 37°C for 1 hour before testing. A uniaxial tensile force was applied to the crown using an Instron machine with a crosshead speed of 5 mm/min until cement failure occurred. Analysis of variance models were fit to determine the effect of TOC, occlusocervical dimension, and cement type of the restorations on the mean tensile strength.

Results For each type of cement, the mean tensile strengths were significantly higher at 20 degrees of TOC and 8 mm of occlusocervical dimension compared with the other preparations. At this preparation, IMProv had the highest mean tensile resistance to dislodgement (47.7 ± 8.4 kg), followed by Fleck's (38.2 ± 8.8 kg), Temp‐Bond (35.9 ± 4.4 kg), and Temp‐Bond plus Vaseline (8.2 ± 2.2 kg). No statistically significant difference was observed between Temp‐Bond and Fleck's zinc phosphate cement when 20 degrees of TOC and 8 mm of occlusocervical dimension was used. There was no statistical difference in the mean tensile resistance to dislodgement for Temp‐Bond plus Vaseline with different preparation designs (p >0.05) except when 20 degrees of TOC and 8 mm of occlusocervical dimension was used. The mean tensile strength was significantly different between Temp‐Bond and Temp‐Bond plus Vaseline for each of the 4 preparation designs (p < 0.05). Among the cements tested, IMProv exhibited higher values, which were statistically different (p < 0.05). Restorations with greater occlusocervical dimension and less TOC exhibited higher tensile resistance to dislodgement.

Conclusions Preparations with 20 degrees of TOC and 8 mm of occlusocervical dimension had significantly higher mean retentive values for all of the cements tested. Significant differences in mean tensile strength were observed, with the highest tensile resistance seen with IMProv, followed by Fleck's cement, and the lowest tensile resistance seen with Temp‐Bond plus Vaseline.
Postcementation hypersensitivity: Scientific data versus dentists’ perceptions
Authors: Rosenstiel Stephen F. , Rashid Robert G.
Published: June 2003

Purpose The purpose of this article was to obtain dentists’ opinions via an Internet survey as to the prevalence, causes, and prevention of postcementation sensitivity and compare their responses with published data on the problem.

Materials and Methods Information as to respondents opinions of postcementation sensitivity was obtained from an Internet survey asking about their experience and for a ranking of the importance of each of 15 factors.

Results A total of 466 valid responses were received. The incidence of postcementation sensitivity was estimated to be less than 2% by more than 2/3 of the dentists. The factors considered “very important” in reducing sensitivity by more than 50% of the respondents were desiccation, luting agent, occlusion, provisional, and water spray.

Conclusions Comparing respondents’ opinions with published clinical studies, the incidence of postcementation sensitivity appears to be underestimated. There is little published evidence to support the importance of antimicrobials, desensitizing, or bonding agents, although these are considered effective by some dentists. Many respondents consider luting agent to be an important variable.
Analysis of the Astro‐1/Hopkins Ultraviolet Telescope EUV–FUV dayside nadir spectral radiance measurements
Authors: Bishop James , Feldman Paul D.
Published: June 2003

The Hopkins Ultraviolet Telescope (HUT) was one of three ultraviolet Astro‐1 observatory instruments on space shuttle Columbia in December 1990 (STS‐35), covering the 830–1850 Å wavelength interval (first order) at ∼3.3 Å spectral resolution. Satellite altitude was 360 km. Dayside nadir measurements were performed during a single orbit on 7 December 1990 under solar maximum (F10.7 = 222), geomagnetically quiet (Ap = 4) conditions, covering late morning local times (solar zenith angle < 48°). These data constitute a reference dayglow radiance spectrum comprising a number of thermospheric emission features, including several weak features neighboring bright optically thick emissions, that have not yet received adequate explanations, in part owing to questions regarding spectral intensity calibration, dynamic range, etc., associated with older data sets. In this paper, the HUT extreme ultraviolet (EUV)–far ultraviolet (FUV) nadir dayglow spectrum is presented along with the results of a modeling analysis using a development version of the Atmospheric Ultraviolet Radiance Integrated Code (AURIC). The analysis relies on currently available laboratory data and first‐principles excitation and transport modeling codes and utilizes constraints drawn from the FUV spectral region data to study several EUV emissions of interest for which past airglow data are sparse. The focus is on the airglow in the 980–1200 Å region, which is particularly rich in emission features affected by thermospheric conditions. Emissions investigated in detail include (1) the optically thick OI 989 Å multiplet and associated 1172 Å fluorescence, (2) the OI 1026 Å sextuplet blended with atomic hydrogen Lyman β, (3) the atomic nitrogen multiplets at 1134 and 1200 Å consisting of optically thick components excited by e− + N and optically thin components excited by e− + N2 and hν + N2, (4) a number of other NI and N+ features (e.g., N+ 1085 Å) excited by N2 dissociative ionization, (5) the Birge‐Hopfield I (N2 BH‐1) system, and (6) the resonance lines of argon (Ar 1048 and 1067 Å).
Beyond magnetotelluric decomposition: Induction, current channeling, and magnetotelluric phases over 90°
Authors: Lezaeta Pamela , Haak Volker
Published: June 2003

This paper presents a method to examine strong current channeling affecting the magnetotelluric (MT) impedances, going beyond existing tensor decomposition schemes. The method allows recognition of elongated conductors in the crust and is also useful for a qualitative recognition of general three‐dimensional (3‐D) high‐conductivity anomalies. This has been tested with synthetic data from 3‐D and 2‐D anisotropic models. The current channeling analysis has been applied to MT data collected in the Andean subduction zone, where the Atacama megafault system close to the Pacific Ocean and oriented subparallel to the coast line is located. The analysis suggests the presence of vertical dike‐like conductors of limited lateral extent along the fault zone. Several MT sites distributed along the faults have impedance phases of the electric field tangential to the local azimuth far exceeding 90° at longer periods. We are able to explain this as being the result of strong current channeling producing magnetic distortion due to an electromagnetic coupling between the conductive ocean and the continental elongated conductors.
Deep generation of magmatic gas on the Moon and implications for pyroclastic eruptions
Authors: Wilson L. , Head J. W.
Published: June 2003

Lunar pyroclastic beads are interpreted to represent primitive magmas derived from great depths and rapidly erupted to the surface in explosive events. However, a detailed mechanism for gas generation at great depth and rapid magma transport to the surface has not yet been described. Furthermore, the pyroclastic beads are not petrogenetically related to basalts erupted near the sampling sites. We propose a model in which these conundrums are resolved through gas build‐up in a low‐pressure micro‐environment near the tip of a magma‐filled crack (dike) propagating rapidly from the magma source depth to the surface. The gas rich region consists of a free gas cavity overlying a foam extending vertically for ∼20 km. Eruption of the foam results in the widespread emplacement of unfractionated pyroclastic beads. Subsequent ascent of the underlying gas‐free picritic magma is unlikely to occur, perhaps accounting for the lack of sampled eruptive equivalents.
Focal segmental sclerotic lesions of the glomerulus in transplanted kidneys assessed using computerized image analysis
Authors: Sugiyama Satoshi , Asano Shinsuke , Tomita Makoto , Hasegawa Midori , Murakami Kazutaka , Kushimoto Hiroko , Shikano Masahiko , Itoh Tohru , Hosinaga Kiyotaka , Kinukawa Tuneo , Matsuura Osamu , Kamihira Osamu
Published: June 2003

Abstract: Mechanisms responsible for the development of focal segmental sclerotic lesions of the glomerulus (FSGS lesions) in transplanted kidneys were investigated by morphometric analysis. The mean glomerular area and the interstitial area were measured using computerized image analysis to compare implantation biopsies (so‐called 1‐h biopsies; 1Bx) with later biopsies (episode Bx; EBx) that had been taken for diagnostic purposes to identify the cause of deteriorating renal function. Groups of patients with (group A,n = 15) or without (group B,n = 10) FSGS lesions were compared. Twelve of 15 in group A and all in group B had lost graft function due to chronic allograft nephropathy. It was found that neither the mean glomerular area nor the interstitial area differed significantly between the two groups in either 1Bx or EBx. The interstitial area was significantly increased (P = 0.007) and the mean glomerular area tended to be increased (P = 0.085) in EBx compared with 1Bx in group A but not in group B. The serum creatinine level at the time of EBx in group A correlated with the interstitial area (P = 0.031) but not the mean glomerular area. However, there was no similar correlation in group B. In conclusion, factors for the development of FSGS lesions in transplanted kidneys may be the increase in interstitial area and possible glomerular hypertrophy following transplantation, rather than pre‐existing reduced renal mass of the donor kidneys.
Cystic fibrosis transmembrane conductance regulator and Na+ channel subunits mRNA transcripts, and Cl− efflux, show a different distribution in rat duodenum and colon
Authors: Odes H. S. , Smirnoff P. , Guberman R. , Pollak‐Charcon S. , Sperber A. D. , Fich A. , Fraser G. M. , Schwartz B.
Published: June 2003

Aim:  We compared the distribution and putative association of Cl– channel transport, CFTR mRNA transcripts, and Na+ channel (ENaC)α‐ and β‐subunit mRNA transcripts in villus and crypt epithelial cells of duodenum, with corresponding surface and crypt cells of colon from sodium‐depleted rats.

Methods:  Cells were loaded with 36Cl– and forskolin‐stimulated efflux was determined. RT‐PCR was performed for CFTR mRNA transcripts and ENaC α‐ and β‐subunit mRNA. Duodenal epithelial cell response to VIP was assessed by measuring intracellular cAMP.

Results:  Forskolin‐stimulated Cl− efflux occurred with decreasing magnitude in duodenal crypt, duodenal villus, colonic crypt and colonic surface cells in Na+‐depleted animals. CFTR expression was correlated directly with Cl− efflux (r = 0.91, P < 0.01). Na+ channel α‐subunit was expressed in colon and duodenum in animals fed diets with a high or low sodium content. While the β‐subunit mRNA was detected in the colon of sodium‐restricted rats, it was absent in the duodenum under control conditions and after Na+ restriction. There was an inverse correlation between mRNA transcripts for CFTR and the ENaC α‐subunit (r = −0.93, P < 0.003) and β‐subunit (r = −0.91, P < 0.004) in colon. VIP‐stimulated cAMP in duodenal epithelial cells was greater in crypt than villus (P < 0.05).

Conclusion:  Cl− efflux, CFTR transcription and forskolin‐stimulated cAMP activity occur in both crypt and villus epithelial cells in duodenum. Possible interaction between CFTR and Na+ channels is apparently limited to parts of the colonic crypt. Lack of duodenal β‐subunit expression makes ENaC activity unlikely.
Behaviour of vastus lateralis muscle–tendon during high intensity SSC exercises in vivo
Authors: Ishikawa M. , Finni T. , Komi P. V.
Published: June 2003

Aims:  The interaction between fascicle and tendinous tissue of human vastus lateralis muscle was investigated during varying intensity stretch–shortening cycle (SSC) jumps performed on a sledge apparatus.

Methods:  Eight subjects performed single leg squat (SJ) and drop jumps (DJ) from a constant dropping height but to different rebound heights. The fascicle length of the vastus lateralis muscle (VL) was determined from real‐time ultrasonography during the movement. Tendon length changes were calculated by subtracting the horizontal part of the fascicle length from the muscle–tendon unit (MTU) length. Simultaneously, kinematic, kinetic and electromyographic data were recorded from leg muscles. In addition, the in vivo patella tendon force was measured from one subject during the trials.

Results:  In all DJs, where MTU was stretched prior to shortening, the fascicle and tendinous tissue of the VL also underwent a SSC. The fascicle lengths decreased and the recoil of tendinous tissue increased with increased rebound intensities (P < 0.05). The force–velocity curves obtained from the MTU showed the expected force–velocity relationship for SSC activities, demonstrating performance enhancement. However, the increased MTU power during the shortening phase of the movement was due primarily to the enhancement of the tendon compartment.

Conclusion:  The results of this study show that, at higher rebound intensities, the fascicle is controlled during the braking phase in a distinct manner so that the effective recoil of the tendon is possible during the final push‐off phase. In addition, the results suggest that the behaviour of fascicle length change depends on the muscle in question in addition to the movement intensity.
An analysis of factors influencing short‐term and sustained response to infliximab treatment for Crohn's disease
Authors: Arnott I. D. R. , McNeill G. , Satsangi J.
Published: June 2003

Background: 59–81% of patients given infliximab for Crohn's disease will respond. Although now in widespread use, little consensus exists regarding the optimal place in patient care. Recently developed guidelines have identified need for markers that predict response.

Aims: We aimed to identify markers of response to infliximab given for Crohn's disease.

Methods: Markers of response (defined at 4 weeks) were prospectively assessed in 74 infliximab‐treated patients with Crohn's disease. Patients were followed‐up to 1 year.

Results: Fifty‐four of 74 (73%) patients responded. Univariate analysis identified that smokers were less likely to respond than non‐smokers [P = 0.005, odds ratio (OR) 0.22]. Patients established on immunosuppression (P = 0.034, OR 7.31) and with isolated colonic disease (P = 0.042, OR 3.83) were more likely to respond. Multiple logistic regression confirmed smoking (P = 0.035, OR 0.24) and colonic disease (P = 0.035, OR 4.87) as independent markers of response. One‐year relapse rates differed significantly between smokers and non‐smokers (100% vs. 39.6%, P = 0.0026, relative risk 3.2) and between patients established on immunomodulators or not (58.0% vs. 92.8%, P = 0.0054, relative risk 2.6).

Conclusions: Smoking has a strong adverse effect on the response rates and maintenance of response to infliximab. Patients on immunomodulators have a more favourable short‐ and long‐term response. These results have important implications for clinical practice.
The expanding role of biological agents in the treatment of inflammatory bowel disease – focus on selective adhesion molecule inhibition
Authors: Rutgeerts P. , Van Deventer S. , Schreiber S.
Published: June 2003

Inflammatory bowel disease presents in various forms. Its increasing incidence indicates that modern lifestyle triggers disease in genetically susceptible individuals. We present a model for inflammatory bowel disease pathophysiology and review the new biological therapies available. These biological agents have been developed to antagonise the processes of pathogenic inflammation, such as the reduction in T‐lymphocyte apoptosis, increase in T‐lymphocyte proliferation and increase in T‐lymphocyte trafficking into the intestinal mucosa. Inhibitors of various inflammatory cytokines, including some antagonists to tumour necrosis factor, are effective therapies for inflammatory bowel disease. However, this class is associated with the risk of rare, but serious, side‐effects, such as opportunistic infections and demyelinating diseases. The administration of anti‐inflammatory cytokines, including interleukin‐10 and interleukin‐11, may theoretically be effective in reducing inflammation, although the clinical development of some of these therapies has been terminated. The selective inhibition of the adhesion molecules involved in T‐lymphocyte trafficking can be effective in reducing gut inflammation. Of the selective adhesion molecule inhibitors under investigation, natalizumab has demonstrated efficacy in inflammatory bowel disease. The future of biological therapy for inflammatory bowel disease shows promise.
Clinical and genetic studies of ETV6/ABL1‐positive chronic myeloid leukaemia in blast crisis treated with imatinib mesylate
Authors: Barbouti Aikaterini , Ahlgren Tomas , Johansson Bertil , Höglund Mattias , Lassen Carin , Turesson Ingemar , Mitelman Felix , Fioretos Thoas
Published: June 2003

Summary. Most chronic myeloid leukaemia (CML) patients are genetically characterized by the t(9;22)(q34;q11), generating the BCR/ABL1 fusion gene. However, a few CML patients with rearrangements of 9q34 and 12p13, leading to ETV6/ABL1 chimaeras, have also been reported. Here we describe the clinical and genetic response to imatinib mesylate treatment of an ETV6/ABL1‐positive CML patient diagnosed in blast crisis (BC). A chronic phase was achieved after acute myeloid leukaemia induction therapy. Then, treatment with imatinib mesylate (600 mg/d) was initiated and the effect was assessed clinically as well as genetically, including by repeated interphase fluorescence in situ hybridization studies. Until d 71 of imatinib mesylate therapy, stable improvements in the clinical and laboratory features were noted, and the frequency of ABL1‐rearranged peripheral blood cells decreased from 56% to 11%. At d 92, an additional t(12;13)(p12;q13), with the 12p breakpoint proximal to ETV6, was found. The patient relapsed into BC 126 d after the start of the imatinib mesylate treatment and succumbed to the disease shortly afterwards. No mutations in the tyrosine kinase domain of ABL1 of the ETV6/ABL1 fusion were identified in the second BC. However, whereas the ETV6/ABL1 expression was seemingly the same at diagnosis and at second BC, the expression of ETV6 was markedly lower at the second BC. This decreased expression of wild‐type ETV6 may have been a contributory factor for the relapse.
Tacrolimus‐associated posterior reversible encephalopathy syndrome after allogeneic haematopoietic stem cell transplantation
Authors: Wong Raymond , Beguelin Guillermo Z. , De Lima Marcos , Giralt Sergio A. , Hosing Chitra , Ippoliti Cindy , Forman Arthur D. , Kumar Ashok J. , Champlin Richard , Couriel Daniel
Published: June 2003

Summary. Neurotoxicity is a significant complication of the use of tacrolimus. From April 1998 to December 2001, we identified 10 patients (six women, four men) who developed 11 episodes of tacrolimus‐associated posterior reversible encephalopathy syndrome (PRES) after allogeneic haematopoietic stem cell transplantation for haematological malignancies. The diagnosis was made by characteristic clinical findings (mental status changes, seizures, neurological deficits) with the exclusion of other causes and characteristic imaging findings. The median age was 35·5 years (range 19–57 years). Seven patients received a matched‐unrelated donor transplant and three received a cord blood transplant. The overall incidence of PRES was 1·6%, while the incidence in matched‐unrelated, mismatched‐related and cord blood transplants was 3·5%, 4·9% and 7·1% respectively. Mental status changes, cognitive deficits, seizures and lethargy were the most common clinical findings. Eight of 10 patients had characteristic findings of hyperintensity of the white matter on T2‐weighted images and FLAIR (fluid‐attenuated inversion recovery) sequence on magnetic resonance imaging of the brain. Serum tacrolimus levels were within the therapeutic range in most patients. Tacrolimus treatment was continued (n = 4) or temporarily withheld (n = 7) for 1–14 d. One patient was changed to cyclosporine. In most patients, subsequent treatment with tacrolimus was well tolerated without recurrence of neurotoxicity.
Bacteria recovered from teeth with apical periodontitis after antimicrobial endodontic treatment
Authors: Chávez de Paz L. E. , Dahlén G. , Molander A. , Möller Å. , Bergenholtz G.
Published: June 2003

Chávez de Paz LE, Dahlén G, Molander A, Möller Å, Bergenholtz G. Bacteria recovered from teeth with apical periodontitis after antimicrobial endodontic treatment. International Endodontic Journal, 36, 500–508, 2003.

Aim  To determine whether there is a pattern for certain bacteria to remain after chemo‐mechanical treatment of root canals in teeth with apical periodontitis.

Methodology  Consecutive root‐canal samples of 200 teeth receiving root‐canal treatment, referred from general practitioners and endodontic specialists for analyses of cultivable microbes, were studied prospectively. To be included, samples had to be taken at a treatment session subsequent to the one at which endodontic therapy was initiated. All samples were from teeth that either presented with clinical or radiographic evidence of apical periodontitis or both. Bacteriological findings were linked to clinical and radiographic parameters including status of the root canal prior to treatment, namely, vital pulp, necrotic pulp or root filled.

Results  A total of 248 strains were isolated from 107 teeth giving bacterial growth. Gram‐positives predominated (85%). Lactobacillus spp. (22%), nonmutans streptococci (18%), and Enterococcus spp. (12%) were the most common isolates. Gram‐negative anaerobes were relatively sporadic. Large radiographic bone lesions, persistent pain and use of intracanal calcium hydroxide dressing correlated with bacterial presence (P < 0.05).

Conclusions  Once established, nonmutans streptococci, enterococci and lactobacilli appear to survive commonly following root‐canal treatment of teeth with clinical and radiographical signs of apical periodontitis.
Large‐scale environmental correlates of forest tree distributions in Catalonia (NE Spain)
Authors: Thuiller Wilfried , Vayreda Jordi , Pino Joan , Sabate Santi , Lavorel Sandra , Gracia Carles
Published: June 2003

Aim To explore the environmental correlates of tree species distributions in Catalonia according to the chorological status of the species.

Location The study area is the region of Catalonia, in north‐eastern Spain.

Methods We used presence‐absence data for 24 species, sampled in random plots distributed throughout forests of Catalonia. A climate model for the Catalonia region provided environmental variables. We used classification tree analysis to explore the environmental correlates of the realized niches of tree species. The predictive accuracy of the models was assessed using the ROC curve approach. Potential distribution maps of tree species were generated for the whole Catalonia region.

Results Models were ranked from low to high accuracy for the 24 species. Differences in accuracy among species were related to the chorological status of species. Zonal species, or species at the core of their range (Mediterranean and Sub‐Mediterranean species), were generally well predicted, while extrazonal species, or species at the edge of their range, were predicted only moderately well. Mediterranean species distributions showed good correlations with extreme temperatures and annual precipitation.

Main conclusions The above trends confirmed the difficulty of identifying the realized niche of species at the edges of their ranges. In contrast, Mediterranean and Sub‐Mediterranean species, which were at the core of their range, were well‐predicted, confirming the importance of extremes of temperature and annual precipitation as effective surrogates for variables having more direct physiological roles in limiting the ability of plants to survive and grow. Maps of potential tree distributions allowed us to define suitable habitats and to highlight areas where species have been planted outside their natural distribution.
Probability of anti‐D development in D− patients receiving D+ RBCs
Authors: Frohn Christoph , Dümbgen Lutz , Brand Jörg‐Matthias , Görg Siegfried , Luhm Jürgen , Kirchner Holger
Published: June 2003

BACKGROUND:In some situations, the administration of D+ RBCs to D– patients is necessary. The probability of a subsequent anti‐D formation is assumed to be around 80 percent, a figure based primarily on studies in healthy volunteers. It was hypothesized that patients requiring blood transfusion have a much lower probability of developing antibodies.

STUDY DESIGN AND METHODS:A retrospective analysis was performed whereby 78 D– patients were evaluated for the development of RBC antibodies after administration of D+ RBCs. For the analysis of the cross‐sectional observations, parametric models were used for interval‐censored data.

RESULTS:Anti‐D was detected in 16 of 78 patients. Considering the individual patient's inspection times, the calculated probability of developing antibody following D+ RBC supply was shown to be below 41.7 percent (upper 95% confidence bound) and estimated as 30.4 percent. The data hinted toward an inverse correlation between the number of transfused units and the probability of antibody formation. Interestingly, 6 of these 16 patients developed additional IgG autoantibody. In 3 of those cases, evidence for prolonged hemolysis was found.

CONCLUSION:The actual frequency of antibody formation in our patients is much lower than assumed. On the other hand, prolonged hemolysis probably induced by additional autoreactive antibodies might occur. This possible complication has not yet been addressed. Further studies might reveal whether a less restricted transfusion policy with respect to D matching is justified in selected patients.
WBC‐containing allogeneic blood transfusion and mortality: a meta‐analysis of randomized controlled trials
Authors: Vamvakas Eleftherios C.
Published: June 2003

BACKGROUND: An association between allogeneic blood transfusion (ABT) and mortality was reported by one team of investigators from randomized controlled trials (RCTs) comparing recipients of non‐WBC‐reduced versus WBC‐reduced RBCs in open‐heart surgery. A meta‐analysis was undertaken to examine whether this finding can be generalized across clinical settings and/or transfused RBC components.

STUDY DESIGN AND METHODS: RCTs reporting on adverse immunomodulatory effects of ABT between January 1992 and August 2002 were retrieved. Fourteen studies had recorded mortality as a primary or secondary outcome and met all other criteria for meta‐analysis. Summary ORs of mortality in a treatment arm receiving WBC‐containing allogeneic RBCs versus a control arm receiving autologous or WBC‐reduced allogeneic RBCs were calculated across studies, for groups of studies in which the hypothesis of homogeneity was not rejected.

RESULTS: There was no association between ABT and mortality across 14 RCTs reporting on short‐term mortality (summary OR, 1.20; 95% CI, 0.87–1.65) or across 3 RCTs reporting on long‐term mortality (summary OR, 0.87; 95% CI, 0.64–1.19). In subgroup analyses, RCTs using autologous blood or conducted in abdominal or vascular surgery showed no difference in mortality, but short‐term mortality differed across 3 RCTs conducted in open‐heart surgery (summary OR, 2.26; 95% CI, 1.31–3.90; p < 0.05) and 7 RCTs comparing recipients of non‐WBC‐reduced versus WBC‐reduced allogeneic RBCs filtered before storage (summary OR, 1.45; 95% CI, 1.00–2.11; p ≥ 0.05).

CONCLUSIONS: An association between ABT and either short‐term or long‐term mortality was not detected across clinical settings and transfused RBC components, but subgroup analyses suggest that an association between WBC‐containing ABT and short‐term mortality may exist in open‐heart surgery and in settings where WBC‐reduced allogeneic RBCs filtered before storage are administered.
WBC reduction of RBC transfusions is associated with a decreased incidence of RBC alloimmunization
Authors: Blumberg Neil , Heal Joanna M. , Gettings Kelly F.
Published: June 2003

BACKGROUND: Allogeneic transfusion stimulates Th2 (humoral) immunity. A hypothesis was developed that WBC reduction, by reducing the Th2 stimulus associated with transfusions, might reduce RBC alloimmunization.

STUDY DESIGN AND METHODS: The first retrospective cohort study involved determining the prevalence of newly detected alloimmunization in transfused patients with acute myeloid leukemia (AML) in our hospital in the period before WBC reduction and after its introduction for this particular group of patients. The second study involved determining the incidence of newly detected RBC alloimmunization in all transfused hospital patients during three annual periods with WBC‐reduction prevalences ranging from 0 to 100 percent.

RESULTS: The alloimmunization prevalence rate in AML patients was 8.2 percent in those receiving non‐WBC‐reduced RBCs and platelets (n=195) and 2.8 percent in those receiving only WBC‐reduced components (n=215) (p=0.016). In all patients, the alloimmunization incidence rate decreased from 3.47 per 1000 antibody screens in 1987 (no WBC reduction) to 2.97 per 1000 in 1999 (40% of transfusions WBC‐reduced) to 2.38 per 1000 in 2001 (100% of transfusions WBC‐reduced) (p=0.0298). A decrease in alloimmunization was observed in both males and females, with the decrease more clearly evident in males.

CONCLUSION: These preliminary data support the hypothesis that WBC reduction may be associated with a reduced frequency of RBC alloimmunization. These findings require confirmation and further investigation.
A Simple Model for the Various Pattern Dynamics of Dunes
Authors: Nishimori Hiraku , Yamasaki Masato , Andersen Ken Haste
Published: June 2003

A simple computational model is proposed that reproduces various aspects of the complex dynamics of dunes such as the barchan dunes formation process, the evolution process from a barchan dune to a seif dune, the network-dunes formation under time-dependent directional winds, etc. Although this model may be oversimplified in several respects, there is a hope that it helps us to sift relevant factors out the vast sea of numerous factors influencing the rich dynamics of desert dunes.
Evolution and Extinction Dynamics in Rugged Fitness Landscapes
Authors: Sibani Paolo , Brandt Michael , Alstrøm Preben
Published: June 2003

After an introductory section summarizing the paleontological data and some of their theoretical descriptions, we describe the "reset" model and its (in part analytically soluble) mean field version, which have been briefly introduced in Letters.1,2 Macroevolution is considered as a problem of stochastic dynamics in a system with many competing agents. Evolutionary events (speciations and extinctions) are triggered by fitness records found by random exploration of the agents' fitness landscapes. As a consequence, the average fitness in the system increases logarithmically with time, while the rate of extinction steadily decreases. This non-stationary dynamics is studied by numerical simulations and, in a simpler mean field version, analytically. We also consider the effect of externally added "mass" extinctions. The predictions for various quantities of paleontological interest (life-time distribution, distribution of event sizes and behavior of the rate of extinction) are robust and in good agreement with available data.
Logistic Map as a Random Number Generator
Authors: Andrecut M.
Published: June 2003

For the largest value of the control parameter, the logistic map is able to generate an infinite chaotic sequence of numbers. Here we describe a simple method for obtaining a random number generator based on this property of the logistic map. Comparing to usual congruential random generators, which are periodic, the logistic random number generator is infinite, aperiodic and not correlated. An aperiodic random number generator is a valuable tool for computer simulation methods.