bluuebunny/crossref_metadata_2025 huggingface dataset:
Role of mesangial Factor V expression in crescent formation in rat experimental mesangioproliferative glomerulonephritis
Authors: Ono Takahiko , Liu Ning , Makino Toshiaki , Nogaki Fumiaki , Nomura Keiko , Muso Eri , Shimizu Fujio , Honda Gisho , Kita Toru
Published: September 2004

It has been suggested that fibrin deposition participates in the development of crescents in active glomerulonephritis (GN). In human IgA nephropathy, which is a common form of mesangioproliferative GN (MsPGN), crescent formation is occasionally observed in active disease, leading to end‐stage renal failure. Factor V is a membrane‐bound potent cofactor for the conversion of prothrombin to thrombin by Factor Xa. An in vivo study was conducted to clarify the contribution of local fibrin production to crescent formation in MsPGN through mesangial Factor V expression. Wistar rats were injected intravenously with rabbit anti‐rat thymocyte serum. Three days after injection, mesangiolysis with intense mesangial Factor V expression was observed and immunoelectron microscopy revealed fibrin localization in mesangiolytic lesions, which had spread into the glomerular basement membrane adjacent to the destroyed mesangium, accompanied by clots in Bowman's space. Marked glomerular fibrin deposition, together with its deposition in Bowman's space and cellular crescent formation, was noted with mesangial proliferation on day 8. Specific bands for Factor V mRNA were also detected from isolated glomeruli. Fibrin deposition and cellular crescent formation were significantly suppressed by treatment with anti‐Factor V antibody. These results suggest that local fibrin production, following mesangial Factor V expression, together with mesangiolysis that spreads to the adjacent glomerular basement membrane, plays a role in crescent formation in MsPGN. Copyright © 2004 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.
Human tuberculous granulomas induce peripheral lymphoid follicle‐like structures to orchestrate local host defence in the lung
Authors: Ulrichs Timo , Kosmiadi George A , Trusov Vsevolod , Jörg Sabine , Pradl Lydia , Titukhina Marina , Mishenko Vladimir , Gushina Nadya , Kaufmann Stefan HE
Published: September 2004

The human tuberculous granuloma provides the morphological basis for local immune processes central to the outcome of tuberculosis. Because of the scarcity of information in human patients, the aim of the present study was to gain insights into the functional and structural properties of infiltrated tissue. To this end, the mycobacterial load in lesions and dissemination to different tissue locations were investigated, as well as distribution, biological functions, and interactions of host immune cells. Analysis of early granuloma formation in formerly healthy lung tissue revealed a spatio‐temporal sequence of cellular infiltration to sites of mycobacterial infection. A general structure of the developing granuloma was identified, comprising an inner cell layer with few CD8+ cells surrounding the necrotic centre and an outer area of lymphocyte infiltration harbouring mycobacteria‐containing antigen‐presenting cells as well as CD4+, CD8+, and B cells in active follicle‐like centres resembling secondary lymphoid organs. It is concluded that the follicular structures in the peripheral rim of granulomas serve as a morphological substrate for the orchestration of the enduring host response in pulmonary tuberculosis. Copyright © 2004 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.
Genome‐wide profiling of oral squamous cell carcinoma
Authors: Chen Yann‐Jang , Lin Shu‐Chun , Kao Tsai , Chang Che‐Shoa , Hong Pei‐She , Shieh Tzong‐Ming , Chang Kuo‐Wei
Published: September 2004

Oral squamous cell carcinoma (OSCC) is a common malignancy, the incidence of which is particularly high in some Asian countries due to the geographically linked areca quid (AQ) chewing habit. In this study, array‐based comparative genomic hybridization was used to screen microdissected OSCCs for genome‐wide alterations. The highest frequencies of gene gain were detected for TP63, Serpine1, FGF4/FGF3, c‐Myc and DMD. The highest frequencies of deletion were detected for Caspase8 and MTAP. Gained genes, classified by hierarchical clustering, were mainly on 17q21–tel; 20q; 11q13; 3q27–29 and the X chromosome. Among these, gains of EGFR at 7p, FGF4/FGF3, CCND1 and EMS1 at 11q13, and AIB1 at 20q were significantly associated with lymph node metastasis. The genomic profiles of FHIT and EXT1 in AQ‐associated and non‐AQ‐associated OSCCs exhibited the most prominent differences. RT‐PCR confirmed the significant increase of TP63 and Serpine1 mRNA expression in OSCC relative to non‐malignant matched tissue. A significant increase in Serpine1 immunoreactivity was observed from non‐malignant matched tissue to OSCC. However, there was no correlation between the frequent genomic loss of Caspase 8 and a significant decrease in Caspase8 expression. These data demonstrate that genomic profiling can be useful in analysing pathogenetic events involved in the genesis or progression of OSCC. Copyright © 2004 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.
Alternatively spliced isoforms of fibronectin in immune‐mediated glomerulosclerosis: the role of TGFβ and IL‐4
Authors: Baelde Hans J , Eikmans Michael , van Vliet Anita I , Bergijk Eline C , Heer Emile de , Bruijn Jan A
Published: September 2004

Fibronectin (FN) is the main extracellular matrix component in glomerulosclerotic lesions. There are different FN isoforms that result from alternative splicing at the EDA and EDB regions of FN mRNA. Increased inclusion of EDA and EDB, which can be elicited by TGFβ, may be conducive to the development of glomerulosclerosis (GS). TGFβ and IL‐4 have previously been shown to play a role in the development of GS. In this study, the mRNA splicing patterns for EDA+ and EDB+ fibronectin were investigated in vivo in various experimental sclerotic glomerulopathies, in vitro in rat mesangial cells (MC) that were stimulated by TGFβ or transfected with IL‐4, and in human kidney biopsies with GS from patients with various kidney diseases. Analysis of glomerular FN mRNA demonstrated inclusion of both ED regions in rats with anti‐Thy1 nephritis or chronic serum sickness and in mice with anti‐GBM glomerulonephritis. Inclusion of both the EDA and EDB regions was associated with glomerular TGFβ expression. In contrast, in mice with Th2‐mediated graft‐versus‐host disease, a model for lupus nephritis, the FN transcripts included neither the EDA nor the EDB region, and renal TGFβ expression was absent. Compared to normal MCs in culture, MCs transfected with IL‐4 produced lower amounts of FN and demonstrated less EDA inclusion, while MC that had been treated with TGFβ showed increased production of FN and more EDA inclusion. Renal biopsies from patients with renal diseases, except those taken from patients with lupus nephritis, showed higher TGFβ levels, higher FN levels, and more EDA inclusion than controls. TGFβ may be a key player in the development of GS by inducing local FN production and alternative splicing of FN mRNA. In lupus glomerulonephritis, in which the involvement of TGFβ in GS is less prominent, Th2 cytokines such as IL‐4 probably account for increased intrarenal collagen synthesis and subsequent FN accumulation from the circulation. In conclusion, neither alternative FN splicing, nor a high transcription level of TGFβ, appears to be a general prerequisite for the development of GS. Copyright © 2004 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.
Photochemical attachment of polymers on planar surfaces with a covalently anchored monolayer of a novel naphthyl ketone photochemical radical generator
Authors: Dayananda K. , Dhamodharan R. , Vijayakumaran K. , Rajamannar T.
Published: September 2004

A monolayer of covalently anchored, novel, binaphthyl ketone is used as a surface‐confined photochemical radical generator (PRG) for anchoring a variety of polymers to silicon surfaces. The precursor PRG is synthesized by the application of a facile and novel method for the oxidation of sterically hindered benzylic hydrocarbons to carbonyl compounds. Oxidation was carried out with a stoichiometric amount of potassium peroxydisulfate, in the presence of a catalytic amount of copper sulfate in an acetonitrile/water mixture. The PRG synthesized is characterized by 1H NMR, UV, and Fourier transform infrared (FTIR). The covalently attached monolayers are characterized by X‐ray photoelectron spectroscopy, ellipsometry, and water contact angle measurements. The method developed is applicable to the preparation of a monolayer of a variety of polymers on a wide range of substrates carrying surface hydroxyl groups. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 5413–5423, 2004
Synthesis and characterization of polyurethane anionomers with bisazoaromatic chromophores and carboxylate groups
Authors: Buruiana Tinca , Buruiana Emil C.
Published: September 2004

A new diol with a bisazoaromatic pendant was prepared to obtain photosensible polymers suitable for dyed aqueous systems. A polyurethane bearing bisazoaromatic chromophores, based on a poly(tetramethylene oxide) diol (average molecular weight = 2000), 2,4‐tolylene diisocyanate, and the aforementioned azo diol, was synthesized and characterized. Bichromophoric polyurethane anionomers, prepared by a two‐step substitution of urethane hydrogen atoms with sodium carboxylate groups, were studied. The influence of the concentration of carboxylate groups (30–158 mequiv of ionic groups/100 g of polymer) on some polymer properties and photoisomerism in polymer solutions and thin films was examined. In particular, the polymer structure and its morphology dictated the proximity of anchored bisazo chromophores and the capability of intermolecular forces between dyes producing hydrogen aggregates in solutions and thin films. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 5463–5470, 2004
Influence of the type of epoxy hardener on the structure and properties of interpenetrated vinyl ester/epoxy resins
Authors: Gryshchuk O. , Karger‐Kocsis J.
Published: September 2004

The morphology–toughness relationship of vinyl ester/cycloaliphatic epoxy hybrid resins of interpenetrating network (IPN) structures was studied as a function of the epoxy hardening. The epoxy was crosslinked via polyaddition reactions (with aliphatic and cycloaliphatic diamines), cationic homopolymerization (via a boron trifluoride complex), and maleic anhydride. Maleic anhydride worked as a dual‐phase crosslinking agent by favoring the formation of a grafted IPN structure between the vinyl ester and epoxy. The type of epoxy hardener strongly affected the IPN morphology and toughness. The toughness was assessed by linear elastic fracture mechanics, which determined the fracture toughness and energy. The more compact the IPN structure was, the lower the fracture energy was of the interpenetrated vinyl ester/epoxy formulations. This resulted in the following toughness ranking: aliphatic diamine > cycloaliphatic diamine ≥ boron trifluoride complex > maleic anhydride. For IPN characterization, the width of the entangling bands and the surface roughness parameters were considered. Their values were deduced from atomic force microscopy scans taken on ion‐etched surfaces. More compact, less rough IPN‐structured resins possessed lower toughness parameters than less compact, rougher structured ones. The latter were less compatible according to dynamic mechanical thermal and thermogravimetric analyses. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 5471–5481, 2004
Pediatric interstitial lung disease revisited
Authors: Fan Leland L. , Deterding Robin R. , Langston Claire
Published: September 2004

The spectrum of pediatric interstitial lung disease (PILD) includes a diverse group of rare disorders characterized by diffuse infiltrates and disordered gas exchange. Children with these conditions typically present with tachypnea, crackles, and hypoxemia. Recent advances have been made in the identification of different types of PILD that are unique to infancy. More exciting has been the discovery of genetic abnormalities of surfactant function, now described in both children and adults. A systematic evaluation of the child presenting with diffuse infiltrates of unknown etiology is essential to the diagnosis. Most often, lung biopsy is required. Current treatment options remain less than satisfactory, and morbidity and mortality remain considerable. © 2004 Wiley‐Liss, Inc.
Transnational living and moving experiences: intensified mobility and dual‐career households
Authors: Hardill Irene
Published: September 2004

In this paper I use household biographies to extend the discussion of transnational living and working by linking transnationalism with writings on the new economy. I specifically focus on some of the ways in which transnational spatial mobility impacts on the production and reproduction of daily life for a subset of transnational élites, heterosexual dual‐career households who are currently living in Canada, the US and the UK. Combining career development and family life has arguably become ever more complicated in the context of perceptions of a breakdown of employment security in the ‘new economy’ and the rise of dual‐career households. While for many households transnational living is brought about because of the career of one partner, non‐economic factors, such as augmenting their own or their children's cultural and social capital, can also result in households having a transnational dimension. Investment in children in the form of education can take precedence over parental career‐related decisions. In this paper, a number of complex living arrangements are presented, with members of the dual‐career household living in both the sending and receiving country. Some households made the difficult decision of declining an assignment abroad for the wellbeing of the household, but the economic cost was the termination of one career with the organisation that requested one partner's relocation abroad. Copyright © 2004 John Wiley & Sons, Ltd.
Mobility, fixity, agency: Australia's working holiday programme
Authors: Clarke Nick
Published: September 2004

Recent writings on transnational corporeal mobility have been dominated by at least two concerns: mobility as ever‐expanding or even complete; and mobility as determined by economic restructuring. In this paper, I confront such writings with empirical material from primarily qualitative research into Australia's working holiday programme, which was established in 1975 to allow British citizens between the ages of 18 and 26 to work and holiday in Australia for a period of up to 12 months. And I confront such writings with M. P. Smith's (2001) agency‐oriented approach to transnational urbanism, which I extend with two arguments. Firstly, since agency is not a simple possession of intent or motivated human beings, the achievement of mobility rests on both human actors and non‐human actants. Secondly, since mobility is not simply increasing, the achievement of mobility rests alongside what we might call relative contingent fixity. Copyright © 2004 John Wiley & Sons, Ltd.
Energy‐level position of bistable (CiCs)0 defect in the B configuration in the forbidden band of n‐Si
Authors: Dolgolenko A. , Varentsov M. , Gaidar G.
Published: September 2004

Phosphorus‐doped silicon samples grown by various methods after irradiation by fast neutrons of a WWR‐M reactor and subsequent annealing at room temperature were investigated. The calculation of the temperature dependence of effective carrier concentration was carried out in the framework of Gossick's model, taking into account the recharges of defects both in the conducting matrix of n‐Si and in the space charge region of defect clusters. The distribution function of electrons in the acceptor level of bistable defect (CiCs)0 was determined in the case when the concentration of this defect is a function of the Fermi level in the conducting matrix of n‐Si. The concentration of bistable CiCs defect and its energy level at (Ec – 0.123 eV) in the forbidden band of silicon were calculated. The absence of reconciliation between the introduction rate of A‐centers in n‐Si, irradiated by fast neutrons of the reactor, and the concentration of oxygen in 1016–1018 cm–3 limits was determined. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Stimulated emission from GaN nanocolumns
Authors: Kikuchi Akihiko , Yamano Kouji , Tada Makoto , Kishino Katsumi
Published: September 2004

Stimulated emission with very low threshold excitation power density was observed for GaN nanocolumns grown on (0001) sapphire substrate by RF‐plasma assisted molecular beam epitaxy. The photopump measurements were carried out under 355 nm Nd:YAG laser excitation with the surface emission configuration. The threshold excitation power density was 198 kW/cm2 at room temperature. The peak wavelength shifted from 370.2 to 370.9 nm when increasing the excitation power from 130 to 440 kW/cm2. The peak intensity increased nonlinearly with excitation power. For the lower excitation condition using a 325 nm He–Cd laser, the spontaneous emission peak was observed at 363.2 nm and the intensity was 20∼30 times stronger than for a 3.7 μm‐thick MOCVD‐grown GaN film with a dislocation density of 3∼5 × 109 cm–2. With this configuration the peak intensity was increased propotionally with excitation power. These results indicate that GaN nanocolumns have high potential to realize high performance optical devices. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
2D Self‐Assembly of Oligo(p‐phenylene vinylene) Derivatives: From Dimers to Chiral Rosettes
Authors: Miura Atsushi , Jonkheijm Pascal , De Feyter Steven , Schenning Albertus P. H. J. , Meijer E. W. , De Schryver Frans C.
Published: September 2004

Enantiomerically pure oligo(p‐phenylene vinylene) diaminotriazine derivatives and a short structurally related achiral diaminotriazine derivative, all having a rigid backbone in common, are studied to self‐assemble at the solution–graphite interface by scanning tunneling microscopy. As a function of the length of the backbone, different two‐dimensional motifs are formed (dimers and rosettes) that are rationalized in terms of the balance between different intermolecular interactions, in this case, intermolecular hydrogen bonding and the packing requirements of the alkyl chains on a graphite surface. In addition, the effect of molecular chirality on monolayer chirality is investigated, revealing molecular size‐dependent expressions of the monolayer chirality.
Suspended Carbon Nanotube Quantum Wires with Two Gates
Authors: Cao Jien , Wang Qian , Wang Dunwei , Dai Hongjie
Published: September 2004

Suspended single‐walled carbon nanotube devices comprised of high‐quality electrical contacts and two electrostatic gates per device have been prepared. Compared to nanotubes pinned on substrates, the suspended devices exhibit little hysteresis related to environmental factors and act as cleaner Fabry–Perot interferometers or single‐electron transistors. The high‐field saturation currents in the suspended nanotubes related to optical phonon or zone‐boundary phonon scattering are significantly lower due to the lack of efficient heat sinking. The multiple‐gate design may also facilitate future investigations into the electromechanical properties of nanotube quantum systems.
Distribution and abundance of West Greenland humpback whales (Megaptera novaeangliae)
Authors: Larsen Finn , Hammond Philip S.
Published: September 2004

Photo‐identification surveys of humpback whales Megaptera novaeangliae were conducted at West Greenland during 1988–93, the last 2 years of which were part of the internationally coordinated humpback whale research programme YoNAH, with the primary aim of estimating abundance for the West Greenland feeding aggregation. The area studied stretched from the coast out to the offshore margin of the banks, determined approximately by the 200 m depth contours, between c. 61°70′N and c. 66°N. The surveys were conducted between early July and mid‐August and 993 h were expended on searching effort. A total of 670 groups of humpback whales was encountered leading to the identification of 348 individual animals. Three areas of concentration were identified: an area off Nuuk; an area at c. 63°30′N; and an area off Frederikshåb. Sequential Petersen capture–recapture estimates of abundance were calculated for five pairs of years at 357 (1988–89), 355 (1989–90), 566 (1990–91), 376 (1991–92), and 348 (1992–93). Excluding the anomalously high estimate in 1990–91, the simple mean is 359 (se= 27.3, CV = 0.076) and the inverse CV‐squared weighted mean is 356 animals (se= 24.9, CV = 0.070). These calculations lead us to conclude that between 1988 and 1993 there were 360 humpbacks (CV = 0.07) in the West Greenland feeding aggregation. Using the Cormack–Jolly–Seber model framework non‐calf survival rate was estimated at 0.957 (se= 0.028). Our data have low power (P < 0.3) to detect a trend of 3.1%, assuming the probability of a type I error was 0.05.
Microclimatic stability in burrows of an Afrotropical solitary bathyergid rodent, the silvery mole‐rat (Heliophobius argenteocinereus)
Authors: Šumbera Radim , Chitaukali W. N. , Elichová M. , Kubová J. , Burda H.
Published: September 2004

Mean depth and mean size of burrow system components, burrow‐soil temperatures and actual diurnal temperatures, humidity and oxygen concentration in burrows of silvery mole‐rats Heliophobius argenteocinereus were measured in two mesic areas in Malawi. Mesic tropic climate, together with soil and plant cover contribute to a diurnally and seasonally stable microclimate even in shallow burrows. Daily and seasonal changes of burrow temperatures were lower compared to those in bathyergids from temperate areas where ambient and burrow temperatures undergo larger fluctuations. Silvery mole‐rats in Malawi are thus probably not distressed by these environmental factors.
Estimation of aerosol optical thickness over northeast Asia from Sea‐Viewing Wide Field‐of‐View Sensor (SeaWiFS) data during the 2001 ACE‐Asia intensive observation period
Authors: Lee Kwon H. , Kim Young J. , von Hoyningen‐Huene Wolfgang
Published: September 2004

Radiative forcing by aerosol is one of the greatest sources of uncertainty in climate change modeling. One of the main objectives of the Asian Pacific Regional Aerosol Characterization Experiment (ACE‐Asia) was to assess the spatial and temporal variability of aerosol properties in northeast Asia. Aerosol optical parameters are retrieved from the Sea‐Viewing Wide Field‐of‐View Sensor (SeaWiFS) satellite data to study aerosol characteristics over northeast Asia during the ACE‐Asia intensive observation period 2001. The aerosol optical thickness (AOT) and Ångström exponent are retrieved over land and ocean at a spatial scale of 1 × 1 km2 by using the Bremen aerosol retrieval (BAER) technique. SeaWiFS‐derived AOT data were compared with those ground‐measured AERONET AOT. The validation between SeaWiFS and Sun photometer data showed good correlation coefficients (r > 0.89) during the ACE‐Asia IOP. The SeaWiFS‐retrieved AOT showed a high AOT value of around 0.8 and an Ångström exponent of 0.51 during an Asian dust case of 13 April 2001 over Gosan. Aerosol parameters retrieved from SeaWiFS data by using the BAER technique showed promising results to monitor atmospheric aerosol loading and estimate its optical properties.
Numerical study of Asian dust transport during the springtime of 2001 simulated with the Chemical Weather Forecasting System (CFORS) model
Authors: Uno Itsushi , Satake Shinsuke , Carmichael Gregory R. , Tang Youhua , Wang Zifa , Takemura Toshihiko , Sugimoto Nobuo , Shimizu Atsushi , Murayama Toshiyuki , Cahill Thomas A. , Cliff Steven , Uematsu Mitsuo , Ohta Sachio , Quinn Patricia K. , Bates Timothy S.
Published: September 2004

The regional‐scale aerosol transport model Chemical Weather Forecasting System (CFORS) is used for analysis of large‐scale dust phenomena during the Asian Pacific Regional Characterization Experiment (ACE‐Asia) intensive observation. Dust modeling results are examined with the surface weather reports, satellite‐derived dust index (Total Ozone Mapping Spectrometer (TOMS) Aerosol Index (AI)), Mie‐scattering lidar observation, and surface aerosol observations. The CFORS dust results are shown to accurately reproduce many of the important observed features. Model analysis shows that the simulated dust vertical loading correlates well with TOMS AI and that the dust loading is transported with the meandering of the synoptic‐scale temperature field at the 500‐hPa level. Quantitative examination of aerosol optical depth shows that model predictions are within 20% difference of the lidar observations for the major dust episodes. The structure of the ACE‐Asia Perfect Dust Storm, which occurred in early April, is clarified with the help of the CFORS model analysis. This storm consisted of two boundary layer components and one elevated dust (>6‐km height) feature (resulting from the movement of two large low‐pressure systems). Time variation of the CFORS dust fields shows the correct onset timing of the elevated dust for each observation site, but the model results tend to overpredict dust concentrations at lower latitude sites. The horizontal transport flux at 130°E longitude is examined, and the overall dust transport flux at 130°E during March–April is evaluated to be 55 Tg.
Origin and properties of plumes of high ozone observed during the Texas 2000 Air Quality Study (TexAQS 2000)
Authors: Daum P. H. , Kleinman L. I. , Springston S. R. , Nunnermacker L. J. , Lee Y.‐N. , Weinstein‐Lloyd J. , Zheng J. , Berkowitz C. M.
Published: September 2004

The Department of Energy (DOE) G‐1 research aircraft made flights on 13 days during the month long Texas 2000 Air Quality Study (TexAQS 2000) to understand the sources and formation mechanism of the very high concentration O3 plumes that are frequently observed in the Houston metropolitan area during the late summer. On six of those days the aircraft sampled plumes exhibiting O3 concentrations in excess of 150 ppbv at a number of different locations in and around the greater Houston area. The composition of these plumes differed significantly from those typically observed in other urban areas, exhibiting unusually high concentrations of hydrocarbon oxidation products such as HCHO and photochemical product species such as peroxides. Estimates of the integrated formation efficiency of O3 with respect to NOx, OPEx, indicate that O3 had been formed in these high concentration plumes with efficiencies ranging between 6.4 and 11 ppbv O3 per ppbv of NOx consumed. Without exception, back trajectories from the locations where these high O3 plumes were observed passed over, or in close proximity to, sources of NOx and hydrocarbons surrounding the Houston Ship Channel. Calculations of instantaneous ozone formation rates and efficiencies using a box model constrained by measurements of stable species showed that ozone formation over and around the Houston Ship Channel could be very rapid (instantaneous rates up to 140 ppbv/h) and very efficient (OPEx up to 28) and, in some instances, limited by the availability of NOx. High concentrations of reactive hydrocarbons and NOx emitted by industries in this area appeared to be the cause of these high rates and efficiencies. Examination of the distribution of photochemical product distributions in the high O3 plumes arising from Ship Channel emissions suggests that O3 formation in these plumes was much more NOx limited than in typical urban plumes at equivalent times in their evolution. However, chemical/transport model simulations with realistic emissions inventories are needed to resolve the question of whether a NOx‐ or hydrocarbon‐based control strategy would be most effective at controlling greater Houston O3 concentrations.
Stable water isotope characterization of human and natural impacts on land‐atmosphere exchanges in the Amazon Basin
Authors: McGuffie K. , Henderson‐Sellers A.
Published: September 2004

Stable water isotopes have been employed as a means of challenging, validating, and improving numerical models of the Amazon Basin since the 1980s. This paper serves as an exemplar of how characterization of human and natural impacts on surface‐atmosphere water exchanges could beneficially exploit stable water isotope data and simulations. Interpretations of Amazonian isotopic data and model simulations are found to be seriously hampered by (1) poor simulation of the gross water budget (e.g., lack of surface water conservation in models); (2) considerable model differences in the fate of precipitation (i.e., between reevaporation and runoff); (3) wide ranging characterization of natural causes of water isotopic fluctuations (especially El Niño and La Niña events); (4) isotopic land‐atmosphere flux sensitivity to the prescription of boundary layer atmospheric water vapor isotopic depletion; and (5) significantly different characterization by current land‐surface schemes of the partition of evaporation between isotopically fractionating (from lakes and rivers) and nonfractionating (transpiration) processes. Despite these obstacles, we find features in the recent isotopic record that might be derived from circulation and land‐use changes. ENSO events may cause decreased depletion in the dry season, because of reduced convective precipitation, while increases in upper basin isotope depletions in the wet season may result from relatively less nonfractionating recycling because there are fewer trees. The promise for isotopic fingerprinting of near‐surface continental water cycle changes depends upon fixing shortcomings in current atmospheric and land‐surface models.
A dynamic aerosol module for global chemical transport models: Model description
Authors: Herzog Michael , Weisenstein Debra K. , Penner Joyce E.
Published: September 2004

We have developed a dynamic aerosol model that is capable of treating the binary nucleation of sulfate gas and its condensation to form aerosol particles. Coagulation among sulfate particles and of sulfate particles with nonsulfate particles is also treated. The model is built in a modular fashion that allows its easy incorporation into a global chemical transport model. The model uses the method of modes and moments to describe the aerosol size distribution, with an arbitrary number of modes possible. The parameterizations in the model are valid for tropospheric as well as stratospheric conditions. No operator splitting or fixed time steps are applied so that all aerosol processes are allowed to fully interact with each other during each time step. Here we examine the predictions of the model in comparison to a sectional model for a suite of test cases chosen to represent the range of possibilities in a global CTM. We show that the predictions for both number and surface area are within a factor of 1.2 of the sectional model for the four mode version of the model and are only slightly degraded if only two modes are specified. The prediction of the number of accumulation mode particles is within a factor of 2.1 of that from the sectional model within the boundary layer.
Effect of El Niño–Southern Oscillation on the dynamical, thermal, and chemical structure of the middle atmosphere
Authors: Sassi F. , Kinnison D. , Boville B. A. , Garcia R. R. , Roble R.
Published: September 2004

A simulation of the middle atmosphere is presented using a general circulation model (GCM) forced with observed sea surface temperature for the period 1950–2000. The GCM extends to the lower thermosphere and reproduces realistic dynamical and temperature distributions. The period contains several El Niño and La Niña events, which are identified using the NINO3 index. Composite anomalies of relevant meteorological fields are obtained by stratifying the northern winter season according to the NINO3 index. These anomalies have the structure of vertically propagating planetary waves extending from the troposphere to the mesosphere. Circulation anomalies in the middle atmosphere are accompanied by large temperature anomalies that are of opposite sign in the stratosphere and mesosphere, the former being warmer and the latter colder during El Niño events. Near the summer mesopause, changes in momentum deposition by parameterized gravity waves results in warming during El Niño. Detailed statistical analysis is used to determine the significance of these anomalies. A chemical/transport simulation is carried out using output from the GCM. It shows that when the lower stratosphere is colder (as during La Niña events), some ozone depletion takes place. Conversely, when the lower stratosphere is warmer and more disturbed, as is the case during El Niño events, heterogeneous chemical processes are inhibited.
Dilution of the Antarctic ozone hole into southern midlatitudes, 1998–2000
Authors: Ajtić J. , Connor B. J. , Lawrence B. N. , Bodeker G. E. , Hoppel K. W. , Rosenfield J. E. , Heuff D. N.
Published: September 2004

The reduction in southern midlatitude ozone is quantified by evaluating the trajectories of ozone‐depleted air masses, assuming that photochemical recovery of ozone in advected air parcels can be ignored. This procedure is carried out for the 3 months from 15 October to 15 January for each of the years 1998, 1999, and 2000. Two distinct source regions, the vortex core and the vortex edge, are considered, and for each day, diabatic reverse domain filling calculations are performed for an ensemble of parcels between 30°S and 60°S and 400–700 K in altitude. In 1998, 1999, and 2000 the mean calculated ozone reduction is 16, 18, and 19 DU, respectively. Air parcels from the vortex edge region are significant contributors to the reduction, especially during spring. Results for four longitudinal and three latitudinal midlatitude subregions are also presented. A comparison with the Total Ozone Mapping Spectrometer measurements of total column ozone shows that without the dilution, ozone over Southern Hemisphere midlatitudes would be 5–6% higher during spring and summer. This result is probably an overestimate due to the neglect of photochemical recovery.
Hurricane forcing on chlorophyll‐a concentration off the northeast coast of the U.S.
Authors: Davis Amélie , Yan Xiao‐Hai
Published: September 2004

The effect of known physical disturbances caused by hurricanes on chlorophyll‐a concentration ([Chl]) is ascertained using remote sensing. This study focuses on all seven hurricanes which affected the northeast (NE) Coast of the U.S. during the Sea‐viewing Wide Field‐of‐view Sensor's (SeaWiFS) lifetime. It is shown that [Chl] increases significantly across the continental shelf of the eastern seaboard after the passage of a hurricane, with also a marked filamentation. The disturbances caused by hurricanes on the biological scale constitute strong and persistent events providing further evidence of the role that upwelling and mixing exert on [Chl] variation.
Is AOU a good measure of respiration in the oceans?
Authors: Ito T. , Follows M. J. , Boyle E. A.
Published: September 2004

Apparent Oxygen Utilization (AOU) is widely used to infer respiration in the oceans by assuming that surface oxygen concentration is close to saturation with the overlying atmosphere. However, significant disequilibrium of oxygen has been observed in high latitude surface oceans where the deep waters are formed. We explicitly calculate True Oxygen Utilization (TOU) in a global ocean physical‐biogeochemical model to evaluate the ability of AOU to represent respiration. We find significant differences between AOU and TOU in the deep waters, suggesting a systematic overestimation of respiration when inferred from AOU. The surface heat flux and the entrainment of thermocline waters together drive the surface undersaturation of oxygen in the regions of water mass formation, and their influences are significantly enhanced by sea ice cover at high latitudes.
Far‐reaching effects of the Hawaiian Islands in the CCSR/NIES/FRCGC high‐resolution climate model
Authors: Sakamoto Takashi T. , Sumi Akimasa , Emori Seita , Nishimura Teruyuki , Hasumi Hiroyasu , Suzuki Tatsuo , Kimoto Masahide
Published: September 2004

For the first time, using a high‐resolution atmosphere‐ocean coupled general circulation model (CGCM), we succeed in reproducing the far‐reaching effects of the Hawaiian Islands, recently showed by satellite observations. The model reproduces the distributions of sea surface temperature (SST), surface winds and cloud liquid water (CLW) in the wake of the Hawaiian Islands. It is revealed that these distributions are caused by the Hawaiian Lee Counter Current (HLCC) and that this current is driven by the wind‐curls induced by the orographic effect of the islands, as suggested from an observational study. It is also shown that wind changes around the Hawaiian Islands can further affect the speed of the North Equatorial Current (NEC) and SST over the current, and intra‐annual variability in CLW to the west of the islands is governed, not only by SST but also by wind speed.
On the spatiotemporal behavior of ozone within the upper mesosphere/mesopause region under nearly polar night conditions
Authors: Hartogh P. , Jarchow C. , Sonnemann G. R. , Grygalashvyly M.
Published: September 2004

The spatiotemporal behavior of the ozone mixing ratio in the upper mesosphere/mesopause region under nearly polar night conditions is one of the phenomena not completely understood and reproduced by models thus far. We examine this issue using an advanced three‐dimensional model of the dynamics and chemistry of the middle atmosphere (0–150 km) particularly designed to investigate the spatiotemporal structure of this phenomenon in the extended mesopause region. The most marked features of the modeling results are a pronounced ozone maximum around 72 km occurring close to the polar night terminator and a strong drop of the mixing ratio above ∼80 km. These features were also found by means of ground‐based microwave measurements in high latitude at the Arctic Lidar Observatory for Middle Atmosphere Research (ALOMAR, 69.29°N, 16.03°E) and even at the moderate latitude of Lindau (51.66°N, 10.13°E) during the night in the winter season but less marked there. They were absent at both stations during the daytime hours. The calculations suggest that the stronger enhanced ozone values occur in a latitudinal band of approximately 15° in the vicinity of the polar night terminator. During nighttime, enhanced values reach into midlatitudes. The effect is confined both to a height interval approximately between 66 and 76 km and to a certain latitudinal range which alters with season according to the change of the polar night terminator. We discuss the model results in terms of chemistry for nearly grazing incidence conditions of the solar insolation and in context with advective transport.
Vertical aerosol distribution over Europe: Statistical analysis of Raman lidar data from 10 European Aerosol Research Lidar Network (EARLINET) stations
Authors: Matthias V. , Balis D. , Bösenberg J. , Eixmann R. , Iarlori M. , Komguem L. , Mattis I. , Papayannis A. , Pappalardo G. , Perrone M. R. , Wang X.
Published: September 2004

Since 2000, regular lidar observations of the vertical aerosol distribution over Europe have been performed within the framework of EARLINET, the European Aerosol Research Lidar Network. A statistical analysis concerning the vertical distribution of the volume light extinction coefficients of particles derived from Raman lidar measurements at 10 EARLINET stations is presented here. The profiles were measured on a fixed schedule with up to two measurements per week; they typically covered the height range from 500 m to 6000 m above ground level (agl). The analysis is made for the planetary boundary layer (PBL) as well as for several fixed layers above ground. The results show typical values of the aerosol extinction coefficient and the aerosol optical depth (AOD) in different parts of Europe, with highest values in southeastern Europe and lowest values in the northwestern part. Annual cycles and cumulative frequency distributions are also presented. We found that higher aerosol optical depths in southern Europe compared to the northern part are mainly attributed to larger amounts of aerosol in higher altitudes. At 9 of the 10 sites the frequency distribution of the aerosol optical depth in the planetary boundary layer follows a lognormal distribution at the 95% significance level.
Radiative forcing from aircraft NOx emissions: Mechanisms and seasonal dependence
Authors: Stevenson David S. , Doherty Ruth M. , Sanderson Michael G. , Collins William J. , Johnson Colin E. , Derwent Richard G.
Published: September 2004

A chemistry‐climate model has been applied to study the radiative forcings generated by aircraft NOx emissions through changes in ozone and methane. Four numerical experiments, where an extra pulse of aircraft NOx was emitted into the model atmosphere for a single month (January, April, July, or October), were compared to a control experiment, allowing the aircraft impact to be isolated. The extra NOx produces a short‐lived (few months) pulse of ozone that generates a positive radiative forcing. However, the NOx and O3 both generate OH, which leads to a reduction in CH4. A detailed analysis of the OH budget reveals the spatial structure and chemical reactions responsible for the generation of the OH perturbation. Methane's long lifetime means that the CH4 anomaly decays slowly (perturbation lifetime of 11.1 years). The negative CH4 anomaly also has an associated negative O3 anomaly, and both of these introduce a negative radiative forcing. There are important seasonal differences in the response of O3 and CH4 to aircraft NOx, related to the annual cycle in photochemistry; the O3 radiative forcing calculations also have a seasonal dependence. The long‐term globally integrated annual mean net forcing calculated here is approximately zero, although earlier work suggests a small net positive forcing. The model design (e.g., upper tropospheric chemistry, convection parameterization) and experimental setup (pulse magnitude and duration) may somewhat influence the results: further work with a range of models is required to confirm these results quantitatively.
Diurnal cycle of tropical precipitation in a general circulation model
Authors: Collier J. Craig , Bowman Kenneth P.
Published: September 2004

Hourly averaged precipitation rates from an ensemble of the Community Climate Model version 3 (CCM3) simulations for the 44‐month period from January 1998 through August 2001 are compared to observations from the Tropical Rainfall Measuring Mission (TRMM) satellite. In order to have adequate sampling by the satellite, comparisons are made for 15° longitude × 10° latitude boxes and for larger geographical areas within the tropics. The temporally and spatially averaged hourly precipitation rates from CCM3 and from TRMM are fit to the diurnal harmonic by the method of linear least squares regression, and the phases and the amplitudes of the diurnal cycles are compared. The model's diurnal cycle is too strong over major land masses, particularly over South America (200% too large), and is too weak over many oceans, particularly the northwestern tropical Pacific (57% too small). The model‐satellite phase differences tend to be more homogeneous. The peak in the model's diurnal harmonic consistently precedes that of the observations nearly everywhere. Phase differences are large over Australia, Papua New Guinea, and Saharan Africa, where CCM3 leads TRMM by 4 hours, 5 to 6 hours, and 9 to 11 hours, respectively. The model's phase and amplitude biases likely have effects on its hydrologic cycle and its surface and atmospheric energy budgets. Thus the causes for the model's biases need to be investigated.
Differences in Tachyarrhythmia Detection and Implantable Cardioverter Defibrillator Therapy by Primary or Secondary Prevention Indication in Cardiac Resynchronization Therapy Patients
Authors: WILKOFF BRUCE L. , HESS MIKE , YOUNG JAMES , ABRAHAM WILLIAM T.
Published: September 2004

Introduction: Although numerous trials have shown benefit of implantable cardioverter defibrillators (ICDs) for either primary or secondary prevention, no trial has prospectively enrolled patients from both indications and analyzed ICD utilization between groups.

Methods and Results: We performed a retrospective review of MIRACLE ICD, a randomized, prospective double‐blind trial of cardiac resynchronization therapy (CRT) in the ICD population. Both secondary prevention (N = 563) and primary prevention patients (N = 415) were enrolled. Subgroup analysis for frequency of ventricular tachycardia (VT) and ventricular fibrillation (VF) episodes and detection accuracy revealed that primary prevention patients had a significantly lower frequency of appropriate episodes (0.09 vs 0.43 episodes/month) at significantly faster cycle lengths (303 ± 54 ms vs 366 ± 71 ms, P < 0.0001). These episodes were more likely to be classified as VF by the device and thus receive shock therapy (42% by device classification vs 19% in secondary prevention, P < 0.0001). The absolute rate of inappropriate detections in the primary prevention group per month of follow‐up was lower but constituted a much higher proportion of all episodes (30% vs 14%, P < 0.0001). Most inappropriate detections in the secondary prevention group were due to rapidly conducted atrial fibrillation; most in the primary prevention patients were due to sinus tachycardia.

Conclusion: Patients receiving an ICD for CRT therapy with primary prevention indications have a different clinical arrhythmia course than patients with a history of spontaneous VT/VF. This has implications for the optimal programming of ICDs. Longer‐term, prospective evaluation of these differences is warranted and should be investigated in the broader ICD patient population.
Comparison of Conventional and Biventricular Antitachycardia Pacing in a Geometrically Realistic Model of the Rabbit Ventricle
Authors: BYRD ISRAEL A. , ROGERS JACK M. , SMITH WILLIAM M. , POLLARD ANDREW E.
Published: September 2004

Introduction: ICDs often are programmed with antitachycardia pacing (ATP) as the first response to ventricular tachycardia (VT). Many ICDs have an additional lead available for ventricular pacing. We hypothesized that using the additional lead for ATP would improve therapy by advancing the orthodromic wavefront, thereby reducing the size of the excitable gap and inducing block of all reentrant activity.

Methods and Results: Monomorphic VT was initiated in a thin‐walled model of rabbit ventricular myocardium that included an apical infarct and anatomically realistic dimensions. ATP with up to eight pulses was delivered at 90% of VT cycle length to one (conventional) or two (biventricular) stimulation areas. Stimulation areas were adjusted from 0.017 cm2 to 0.169 cm2 to modulate interactions between the antidromic and VT wavefronts, and between the orthodromic wavefront and the VT's refractory region. During conventional ATP, we found that larger stimulation areas terminated the VT in three pulses. Continued pacing after termination caused VT reinitiation in the reversed direction in some instances. With smaller stimulation areas, conventional ATP simply reset the circuit. During biventricular ATP, larger stimulation areas terminated VT in one pulse. There were no instances of reinitiation with reversal. However, with smaller stimulation areas, prolongation of refractoriness near the additional stimulation area facilitated induction of functional reentry with pathways modified by continued pacing.

Conclusion: Our modeling suggests that biventricular ATP is superior to conventional ATP under conditions where the additional ventricular lead effectively advances the orthodromic wavefront. Failure to achieve this advancement poses a risk of VT acceleration.