bluuebunny/crossref_metadata_2025 huggingface dataset:
Uptake of pesticides from water by curly waterweed Lagarosiphon major and lesser duckweed Lemna minor
Authors: de Carvalho Renato F , Bromilow Richard H , Greenwood Richard
Published: June 2007

The uptake of pesticides from water by two aquatic plants, the submersed Lagarosiphon major (Ridley) Moss and the floating duckweed Lemna minor L., was measured over periods of up to 72 h. Twelve non‐ionised pesticides and analogues, chosen to span a wide range of physicochemical properties, and one analogue (3,5‐D) of the phenoxyacetic acid herbicide 2,4‐D were studied. Concentrations of the parent compound were determined in the plants following extraction and separation by chromatography. Quantification was by liquid scintillation counting for the 14C‐labelled compounds and by high‐performance liquid chromatography for the four non‐radiolabelled commercial pesticides. Uptake for all compound and plant combinations had reached equilibrium by 24 h. Accumulation of compound in the plant could be described well for most non‐ionised compounds by equilibration into the aqueous phase in the plant cells together with partitioning onto the plant solids, this latter process becoming dominant in Lagarosiphon for compounds with log Kow > 1 and in Lemna for compounds with log Kow > 1.8. Lipophilic compounds with log Kow > 4 were concentrated more than 100‐fold on a fresh‐weight basis. However, the uptake of isoproturon and chlorotoluron was up to threefold less than expected from their Kow values, and their behaviour was better explained using solvation descriptors. Uptake of the acid 3,5‐D was dependent on solution pH, this compound being strongly taken up at lower pH by the process of ion trapping, as previously observed in barley roots. Aquatic vegetation can thus rapidly accumulate pesticides, and could be an important sink especially for lipophilic pesticides reaching well‐vegetated waters. Copyright © 2007 Society of Chemical Industry
Juvenile hormonal activity of mono‐ and polyenehomobenzenes in Drosophila virilis, Spodoptera frugiperda and Araschnia levana
Authors: Demuth Martin , Zambrano Jorge L , Rosales Viale , Lorenz Matthias W
Published: June 2007

A series of mono‐ and polyenehomobenzenes was synthesised by a highly regioselective palladium‐catalysed allylic alkylation of substituted and unsubstituted benzylic Grignard reagents employing catalytic amounts of catalyst and tested for juvenile hormone activity on the fruit fly Drosophila virilis Sturtevant (Diptera: Drosophilidae), on an important agricultural pest species, the fall armyworm Spodoptera frugiperda JE Smith (Lepidoptera: Noctuidae), and on the map butterfly Araschnia levana L. (Lepidoptera: Nymphalidae). In D. virilis only polyenehomobenzenes with a geranyl chain and a methyl, methoxy or isopropyl group at the para position of the aromatic ring displayed significant juvenile hormonal activity at low doses. A monoenehomobenzene and polyenehomobenzenes with longer allylic chains or without a substituted aromatic ring were not active. In S. frugiperda and in A. levana, a mono‐, a di‐ and a tetraene displayed juvenile hormonal activity. In the lepidopteran species, a trend for the necessity of a substitution at position 4 of the phenyl group for high juvenile hormonal activity was also found. Copyright © 2007 Society of Chemical Industry
Development and validation of an infant morbidity index using latent variable models
Authors: Liu Xuefeng , Roth Jeffrey
Published: June 2007

Birth defect, abnormal condition of the newborn, developmental delay or disability and low birth weight are four major infant morbidity outcomes. Most studies have focused on assessment of the effects of risk factors on each of these outcomes or of the relationship among these outcomes or both. Little attention has been paid to the development of a composite index, which is a summary construct of infant morbidity outcomes. In this paper, we develop extended latent variable (LV) models and modified Gauss–Newton algorithms for multiple multinomial morbidity outcomes with complete responses. By assuming the marginal distribution of the LV to be log‐normal, we model the conditional probability of each outcome as a nonlinear
function of the LV, which has properties similar to the logistic function. The estimated generalized nonlinear least‐square method is used to solve equations for parameters of interest. The models are applied to an infant morbidity data set. A new single variable, called infant morbidity index (IMI) that functions as a summary of four infant morbidity outcomes and represents propensity for infant morbidity, is developed. The validity of this index is then assessed in detail. It is shown that the IMI is correlated with each of the individual outcomes, with infant mortality and with a face‐valid index of morbidity outcomes, and can be used in future research as a measure of propensity for infant morbidity. Copyright © 2007 John Wiley & Sons, Ltd.
Impact of nuchal cord on measurement of fetal nuchal translucency thickness
Authors: Scheier M. , Egle D. , Himmel I. , Ramoni A. , Viertl S. , Huter O. , Marth C.
Published: June 2007

Objective

To define the impact of nuchal cord on the measurement of fetal nuchal translucency thickness (NT).

Methods

Between December 2004 and June 2006, we examined prospectively 53 fetuses that were observed on routine first‐trimester ultrasound examination between 11 + 3 and 13 + 6 weeks of gestation to have nuchal cord causing an indentation in the skin in the nuchal region. The fetuses were re‐examined after a median interval of 132 min, when the cord was no longer around the neck and indentation of the skin had resolved. Various NT measurements (highest, lowest, mean) with the cord located around the neck (nuchal cord) were compared with NT measurements in the absence of nuchal cord (‘true’ NT) in the same fetuses. Measurements were considered to be equal when they were within mean ± 1.96 SD, defined by our own intraobserver repeatability according to the method of Bland and Altman.

Results

The mean of the largest and the smallest of six measurements in the presence of nuchal cord fell within the mean ± 1.96 SD of our own intraobserver repeatability, i.e. gave a correct estimate of the true NT, in 80% of fetuses, while the NT was overestimated in 10% and underestimated in 10% of fetuses. The largest and the smallest of six measurements in the presence of nuchal cord gave an underestimate of the true NT in 2% of fetuses and an overestimate in 4% of fetuses, respectively.

Conclusion

There is a wide scattering of measurements in fetuses with nuchal cord in comparison to the same fetuses in the absence of nuchal cord. This prevents accurate prediction of the true NT, although the largest and smallest of repeat measurements with nuchal cord can allow calculation of the highest and lowest possible risks, respectively. These facts must be taken into consideration in counseling patients. Copyright © 2007 ISUOG. Published by John Wiley & Sons, Ltd.
A dynamic channel assignment scheme for clustered multihop cellular networks
Authors: Li Xue Jun , Chong Peter Han Joo
Published: June 2007

Whereas cellular systems have traditionally adopted single‐hop transmissions between the mobile station (MS) and the base station (BS), researchers expect multihop transmission to be utilised in the future. Cellular systems present several challenges, such as channel assignment, which are exacerbated by multimedia service traffic and an increasing number of subscribers. Recently, a clustered multihop cellular network (cMCN) architecture that complements traditional cellular systems has been proposed and studied using fixed channel assignment (FCA). However, the performance of FCA is limited when the traffic pattern varies in a service area. This paper proposes the use of dedicated information ports (DIPs) as clusterheads in cMCN, followed by a multihop dynamic channel assignment (mDCA) scheme. The mDCA works by assigning channels based on information about interference in surrounding cells. Two different channel searching strategies are developed and evaluated. Through computer simulation, we show that the proposed mDCA is able to achieve a significantly improved capacity which is maintained when the number of system channels is increased. Finally, issues regarding the implementation of the mDCA and future work on this topic are discussed. Copyright © 2007 John Wiley & Sons, Ltd.
Cytochrome P450 2C9 is involved in flow‐dependent vasodilation of peripheral conduit arteries in healthy subjects and in patients with chronic heart failure
Authors: Fischer Dieter , Landmesser Ulf , Spiekermann Stephan , Hilfiker‐Kleiner Denise , Hospely Marian , Müller Maja , Busse Rudi , Fleming Ingrid , Drexler Helmut
Published: June 2007

Background

Flow‐mediated dilation (FMD) of human conduit arteries is, in part, related to shear stress‐induced release of endothelium‐derived nitric oxide (NO). However, NO synthase inhibitors do not completely abolish this FMD‐response. Recently, a cytochrome P450 (CYP) epoxygenase of the 2C family was linked to NO‐ and prostacyclin‐independent relaxation of conduit arteries. We therefore evaluated the contribution of CYP 2C9 to FMD in humans.

Methods and results

FMD of the radial artery was determined in 12 healthy volunteers by high‐resolution ultrasound and analyzed before and after intra‐arterial infusion of sulfaphenazole, a specific CYP 2C9 inhibitor, L‐NMMA (NO synthase inhibitor) and co‐infusion of both. Endothelium‐independent vasodilation was characterized after intra‐arterial infusion of SNP. FMD was reduced after sulfaphenazole (11.5±0.87% vs. 7.4±0.95%, p<0.01), after L‐NMMA (6.0±0.71%; p<0.01), and after co‐infusion 3.9±0.73% (p<0.05 vs. L‐NMMA; p<0.01 vs. sulfaphenazole). Sulfaphenazole had no effect on endothelium‐independent vasodilation. In patients with chronic heart failure, the portion of FMD blocked by sulfaphenazole was not affected. CYP 2C was detected by immunohistochemistry in radial artery samples obtained from patients undergoing coronary bypass surgery.

Conclusions

FMD in human conductance arteries is reduced after inhibition of CYP 2C9, supporting the concept that CYP 2C metabolites contribute to endothelium‐mediated vasodilation of peripheral conduit arteries in vivo. In patients with heart failure, the CYP‐dependent FMD appears to be preserved.
Distinct roles of TIR and non‐TIR regions in the subcellular localization and signaling properties of MyD88
Authors: Nishiya Tadashi , Kajita Emi , Horinouchi Takahiro , Nishimoto Arata , Miwa Soichi
Published: June 2007

MyD88 is a cytoplasmic adaptor protein that is critical for Toll‐like receptor (TLR) signaling. The subcellular localization of MyD88 is characterized as large condensed forms in the cytoplasm. The mechanism and significance of this localization with respect to the signaling function, however, are currently unknown. Here, we demonstrate that MyD88 localization depends on the entire non‐TIR region and that the correct cellular targeting of MyD88 is indispensable for its signaling function. The Toll‐interleukin I receptor‐resistance (TIR) domain does not determine the subcellular localization, but it mediates interaction with specific TLRs. These findings reveal distinct roles for the TIR and non‐TIR regions in the subcellular localization and signaling properties of MyD88.
α‐Tomatine, the major saponin in tomato, induces programmed cell death mediated by reactive oxygen species in the fungal pathogen Fusarium oxysporum
Authors: Ito Shin-ichi , Ihara Takashi , Tamura Hideyuki , Tanaka Shuhei , Ikeda Tsuyoshi , Kajihara Hiroshi , Dissanayake Chandrika , Abdel-Motaal Fatma F. , El-Sayed Magdi A.
Published: June 2007

The tomato saponin α‐tomatine has been proposed to kill sensitive cells by binding to cell membranes followed by leakage of cell components. However, details of the modes of action of the compound on fungal cells are poorly understood. In the present study, mechanisms involved in α‐tomatine‐induced cell death of fungi were examined using a filamentous pathogenic fungus Fusarium oxysporum. α‐Tomatine‐induced cell death of F. oxysporum (TICDF) occurred only under aerobic conditions and was blocked by the mitochondrial F0F1‐ATPase inhibitor oligomycin, the caspase inhibitor D‐VAD‐fmk, and protein synthesis inhibitor cycloheximide. Fungal cells exposed to α‐tomatine showed TUNEL‐positive nuclei, depolarization of transmembrane potential of mitochondria, and reactive oxygen species (ROS) accumulation. These results suggest that TICDF occurs through a programmed cell death process in which mitochondria play a pivotal role. Pharmacological studies using inhibitors suggest that α‐tomatine activates phosphotyrosine kinase and monomeric G‐protein signaling pathways leading to Ca2+ elevation and ROS burst in F. oxysporum cells.
Suppression of HIV replication using RNA interference against HIV‐1 integrase
Authors: Lau Tat San , Li Yonggang , Kameoka Masanori , Ng Tzi Bun , Wan David Chi Cheong
Published: June 2007

RNA interference (RNAi) has become one of the most powerful and popular approach on gene silencing in clinical research study especially in virology due to the gene‐specific suppression property of small interfering RNA (siRNA). In this report, we demonstrate that expression of vector‐mediated small hairpin RNA (shRNA) against human immunodeficiency virus type 1 (HIV‐1) integrase (IN), one of the three important enzymes in HIV infection by controlling the integration of viral RNA to host DNA, could suppress the protein synthesis of EGFP‐tagged IN in HeLa cell model efficiently. Furthermore, we show that IN shRNA can successfully reduce the HIV particles production in 293T cells at the level similar to the positive control of HIV‐1 tat shRNA. These results provide the therapeutic possibility of HIV replication using RNAi against HIV‐1 integrase.
Low‐volume, high‐throughput sandwich immunoassays for profiling plasma proteins in mice: Identification of early‐stage systemic inflammation in a mouse model of intestinal cancer
Authors: Forrester Sara , Hung Kenneth E. , Kuick Rork , Kucherlapati Raju , Haab Brian B.
Published: June 2007

Mouse models of human cancers may provide a valuable resource for the discovery of cancer biomarkers. We have developed a practical strategy for profiling specific proteins in mouse plasma using low‐volume sandwich‐immunoassays. We used this method to profile the levels of 14 different cytokines, acute‐phase reactants, and other cancer markers in plasma from mouse models of intestinal tumors and their wild‐type littermates, using as little as 1.5μl of diluted plasma per assay. Many of the proteins were significantly and consistently up‐regulated in the mutant mice. The mutant mice could be distinguished nearly perfectly from the wild‐type mice based on the combined levels of as few as three markers. Many of the proteins were up‐regulated even in the mutant mice with few or no tumors, suggesting the presence of a systemic host response at an early stage of cancer development. These results have implications for the study of host responses in mouse models of cancers and demonstrate the value of a new low‐volume, high‐throughput sandwich‐immunoassay method for sensitively profiling protein levels in cancer.
Analysis of Pathway Activity in Primary Tumors and NCI60 Cell Lines Using Gene Expression Profiling Data
Authors: Feng Xing-Dong , Huang Shu-Guang , Shou Jian-Yong , Liao Bi-Rong , Yingling Jonathan M. , Ye Xiang , Lin Xi , Gelbert Lawrence M. , Su Eric W. , Onyia Jude E. , Li Shu-Yu
Published: June 2007

To determine cancer pathway activities in nine types of primary tumors and NCI60 cell lines, we applied an in silico approach by examining gene signatures reflective of consequent pathway activation using gene expression data. Supervised learning approaches predicted that the Ras pathway is active in ~70% of lung adenocarcinomas but inactive in most squamous cell carcinomas, pulmonary carcinoids, and small cell lung carcinomas. In contrast, the TGF-β, TNF-α, Src, Myc, E2F3, and β-catenin pathways are inactive in lung adenocarcinomas. We predicted an active Ras, Myc, Src, and/or E2F3 pathway in significant percentages of breast cancer, colorectal carcinoma, and gliomas. Our results also suggest that Ras may be the most prevailing oncogenic pathway. Additionally, many NCI60 cell lines exhibited a gene signature indicative of an active Ras, Myc, and/or Src, but not E2F3, β-catenin, TNF-α, or TGF-β pathway. To our knowledge, this is the first comprehensive survey of cancer pathway activities in nine major tumor types and the most widely used NCI60 cell lines. The “gene expression pathway signatures” we have defined could facilitate the understanding of molecular mechanisms in cancer development and provide guidance to the selection of appropriate cell lines for cancer research and pharmaceutical compound screening.
A Survey of the Availability of Primary Bioinformatics Web Resources
Authors: Thireou Trias , Spyrou George , Atlamazoglou Vassilis
Published: June 2007

The explosive growth of the bioinformatics field has led to a large amount of data and software applications publicly available as web resources. However, the lack of persistence of web references is a barrier to a comprehensive shared access. We conducted a study of the current availability and other features of primary bioinformatics web resources (such as software tools and databases). The majority (95%) of the examined bioinformatics web resources were found running on UNIX/Linux operating systems, and the most widely used web server was found to be Apache (or Apache-related products). Of the overall 1,130 Uniform Resource Locators (URLs) examined, 91% were highly available (more than 90% of the time), while only 4% showed low accessibility (less than 50% of the time) during the survey. Furthermore, the most common URL failure modes are presented and analyzed.
Nonlinear 40Ar/39Ar age systematics along the Gilbert Ridge and Tokelau Seamount Trail and the timing of the Hawaii‐Emperor Bend
Authors: Koppers Anthony A. P. , Staudigel Hubert , Phipps Morgan Jason , Duncan Robert A.
Published: June 2007

Over the last three decades the first‐order correlation in morphology and orientation of seamount trails has been called upon to support the concept of a “fixed” Pacific hot spot frame of reference and to explain the Hawaii‐Emperor bend (HEB) by a dramatic change in Pacific plate motion. In this paper, however, we present 40Ar/39Ar ages for the Gilbert Ridge and Tokelau Seamounts (Pacific) that show similar changes or bends in their orientation, but at different geological times, up to 20 Myr earlier than the HEB. Changes in Pacific plate motion alone cannot explain these observations, because these asynchronous bends should have been reflected in the morphology of each of these seamount trails. Together with the lack of (linear) age progressions and inconsistent apparent local plate velocities of 131 and 87 mm/yr, we rule out a fixed hot spot origin for the Gilbert Ridge and Tokelau seamount trails. Instead we invoke secondary or alternate processes to explain the complex age systematics and morphologies in these seamount trails. We propose here that the HEB‐type bends in these seamount trails were likely formed by short‐term “jerk‐like” plate extensions in the studied southwestern region of the Pacific plate, reactivating a preconditioned lithosphere that can be characterized by a complex structure and precursory magmatic impingements. The remarkable differences observed in these colinear seamount trails fundamentally question the existence of HEB‐type bends in the formation of Pacific volcanic lineaments. They also show us that applying geometric and morphologic observations alone is insufficient in constraining past plate motions. Nevertheless, the need and search for alternate volcano‐tectonic mechanisms offer opportunities to better understand intraplate volcanism in general.
Interdecadal variability of ENSO in 21 IPCC AR4 coupled GCMs
Authors: Lin Jia‐Lin
Published: June 2007

This study evaluates the interdecadal variability of El Nino/Southern Oscillation (ENSO) in 21 coupled general circulation models (CGCMs) participating in the Inter‐governmental Panel on Climate Change (IPCC) Fourth Assessment Report (AR4). 110 years of the Climate of the 20th Century (20C3M) simulations are analyzed using wavelet analysis. The results show that the state‐of‐the‐art CGCMs display a wide range of skill in simulating the interdecadal variability of ENSO. The 21 models can be categorized into three groups. The first group (8 models) shows an oscillation with a constant period shorter than the observed ENSO period, and sometimes with a constant amplitude. The second group (5 models) does not produce many statistically significant peaks in the ENSO frequency band, but usually produces one or two prominent peaks (episodes) at period longer than 6 years. The third group (8 models) displays significant interdecadal variability of ENSO in both amplitude and period. Among them, only the MPI model reproduces the observed eastward shift of the westerly anomalies in the low‐frequency regime.
An ion drag contribution to the lower thermospheric wind in the summer polar region
Authors: Tsuda T. T. , Nozawa S. , Brekke A. , Ogawa Y. , Motoba T. , Roble R. , Fujii R.
Published: June 2007

Using the European incoherent scatter (EISCAT) Svalbard radar located in Longyearbyen (78.2°N, 16.0°E) and with the EISCAT UHF radar located in Tromsø (69.6°N, 19.2°E), we have analyzed the data obtained for six consecutive days from 1000 UT on 1 July 1999 to 1000 UT on 7 July 1999 to investigate the importance of ion drag on the lower thermospheric wind dynamics in the summer polar region. The electric field observed at Longyearbyen exhibited a stable diurnal variation primarily occurring throughout the first 3 days of observations, while, during the latter 3 days, the diurnal variation was not clearly identified. The electric field observed at Tromsø did not exhibit such a stable variation. On the basis of the difference of the electric field variation observed at Longyearbyen, we divided the data sets into two intervals with a length of 3 days each. We compared the horizontal velocities of the ions and the neutral gases. At upper heights (∼110–120 km) on the first 3 days, the difference between the ion and neutral motion was clearly identified at Longyearbyen, while it was not at Tromsø. We compared the diurnal tidal amplitudes and phases of the two intervals derived from the Longyearbyen data. The amplitude of the meridional diurnal tide for the first 3 days was larger than that of the latter 3 days over the height region between 100 and 118 km at Longyearbyen. Furthermore, we compared ion drag accelerations with total accelerations. We concluded that the ion drag played an important role in the diurnal amplitude at Longyearbyen on the first 3 days of the observations. In addition, we compared the National Center for Atmospheric Research thermosphere‐ionosphere‐mesosphere‐electrodynamics general circulation model (TIME‐GCM) predictions with the observations. The TIME‐GCM predictions also indicated that the diurnal tide is influenced by the convection electric field.
Broadband very low frequency measurement of D region ionospheric perturbations caused by lightning electromagnetic pulses
Authors: Cheng Zhenggang , Cummer Steven A. , Su Han‐Tzong , Hsu Rue‐Ron
Published: June 2007

Prompt early/fast perturbations on narrowband sub‐ionospherically propagating very low frequency (VLF) signals are the primary evidence for the direct coupling of energy released by lightning discharge to the lower ionosphere. Different mechanisms have been advanced to explain the fast ionospheric perturbations, such as heating and ionization from the lightning electromagnetic pulse (EMP) associated with elves or from quasielectrostatic fields associated with sprites and halos. By comparing the broadband VLF spectra (3–25 kHz) of lightning discharges that shortly followed high peak current lightning discharges with the spectra of lightning discharges that did not, we detect D region perturbations caused by these intense lightning strokes over the U.S. East Coast and the U.S. High Plains. The electron density changes are measured by analyzing the broadband VLF propagation changes, and the perturbed electron density profiles from both regions are found to be consistent with those theoretically predicted for strong lightning EMP. In one case, a D region perturbation was detected following a lightning stroke that produced an isolated elve recorded by the Imager of Sprites and Upper Atmospheric Lightning (ISUAL) instrument on the FORMOSAT‐2 satellite, confirming the EMP origins of these ionospheric perturbations. For this case, we measure electron density enhancements of 460 cm−3 averaged over a 220‐km radius and 10‐km‐high perturbation region, in good agreement with the 210 cm−3 measured optically by Mende et al. (2005) for a different elve event. The characteristics of the lightning responsible for these ionospheric perturbations are investigated by comparing high peak current lighting strokes that do and do not generate detectable ionospheric perturbations.
Statistical characteristics of the day‐to‐day variability in the geomagnetic Sq field
Authors: Chen Gen‐Xiong , Xu Wen‐Yao , Du Ai‐Min , Wu Ying‐Yan , Chen Bo , Liu Xiao‐Can
Published: June 2007

Day‐to‐day variability in the geomagnetic Sq field is studied by using the magnetic data from a meridian chain of magnetometers along 120°E longitude. The method of natural orthogonal components (NOC or eigenmode analysis) is applied to separate the Sq variation from complicated disturbances. The first eigenmode with the largest eigenvalue represents fairly well the Sq variation with a conspicuous day‐to‐day variability in the daily range. For the stations on the same north‐ or south‐side of the Sq current system focus, the day‐to‐day variations show a positive correlation. In contrast, for the stations on the different sides of the Sq focus, they show a negative correlation, suggesting an important role of latitudinal shift of the Sq current system focus to the day‐to‐day variability in the Sq daily range. The Sq daily range is correlated with the magnetic indices Ap and Dst in a peculiar way: On some severe disturbed days, noticeable enhancements of the Sq are observed, implying increases in the ionospheric conductivities and/or tidal wind velocities; on other severe disturbed days, however, dramatically reduced Sq variations occur, suggesting dominant effects of the “disturbance dynamo” process.
Generation and evolution of intense ion cyclotron turbulence by artificial plasma cloud in the magnetosphere
Authors: Ganguli Gurudas , Rudakov Leonid , Mithaiwala Manish , Papadopoulos Konstantinos
Published: June 2007

It is shown that intense ion cyclotron turbulence can be induced in the near‐Earth space by shaped release of neutral gas of materials such as lithium, cesium, etc. Release of 1 ton of neutral lithium gas in the Earth's equatorial plane at L = 2 can introduce about 30 GJ of energy which can be used to excite waves around the lithium ion cyclotron harmonics that readily evolves into the turbulent state. The energy is obtained by converting the orbital kinetic energy of the neutral lithium atoms into free energy for the electromagnetic waves through photoionization and creation of a ring distribution in the lithium ion velocity perpendicular to the ambient magnetic field. This distribution function is highly unstable and can spontaneously trigger large amplitude shear Alfven waves near lithium cyclotron harmonics with unique nonlinear properties. These waves lead to pitch angle scattering of the trapped electrons in a broad energy band.
A record of ozone variability in South Pole Antarctic snow: Role of nitrate oxygen isotopes
Authors: McCabe Justin R. , Thiemens Mark H. , Savarino Joel
Published: June 2007

The information contained in polar nitrate has been an unresolved issue for over a decade. Here we demonstrate that atmospheric nitrate's oxygen isotopic composition (Δ17O‐NO3) reflects stratospheric chemistry in winter and tropospheric chemistry in summer. Surface snow isotope mass balance indicates that nitrate oxygen isotopic composition is the result of a mixture of 25% stratospheric and 75% tropospheric origin. Analysis of trends in Δ17O‐NO3 in a 6 m snow pit that provides a 26‐year record reveals a strong 2.70‐year cycle that anticorrelates (R = −0.77) with October–November–December column ozone. The potential mechanisms linking the records are either denitrification or increased boundary layer photochemical ozone production. We suggest that the latter is dominating the observed trend and find that surface ozone and Δ17O‐NO3 correlate well before 1991 (R = 0.93). After 1991, however, the records show no significant relationship, indicating an altered oxidative environment consistent with current understanding of a highly oxidizing atmosphere at the South Pole. The disappearance of seasonal Δ17O‐NO3 trends in the surface layer at depth remain unresolved and demand further investigation of how postdepositional processes affect nitrate's oxygen isotope composition. Overall, the findings of this study present a new paleoclimate technique to investigate Antarctic nitrate records that appear to reflect trends in stratospheric ozone depletion by recording tropospheric surface ozone variability.
Global source attribution of tropospheric ozone: Long‐range transport from various source regions
Authors: Sudo K. , Akimoto H.
Published: June 2007

We examine contributions from various source regions to global distributions and budgets of tropospheric ozone (O3) in the context of intercontinental transport, using tagged tracer simulation with a global chemical transport model. For tagging O3, we consider regional separation of the model domain on the basis of the distributions of O3 chemical production. We define 14 polluted source regions (14 tracers) in the boundary layer (North America, Europe, China, etc.) and 8 regions (8 tracers) in the free troposphere; O3 production in the remaining (remote) tropospheric region and O3 transport from the stratosphere are also tagged as separate tracers. O3 transport from the polluted source regions like North America, Europe, and Asia generally accounts for more than 40% of ozone abundances even in remote locations. O3 exports from boundary layer in China and Asian free troposphere are discerned through much of the Northern Hemisphere, suggesting significant and extensive impacts of eastern Asian pollution. In particular, O3 from Asian free troposphere plays the most important roles in distribution and seasonal variation of O3 in the middle‐upper troposphere almost globally. In June–September, the model calculates a large O3 contribution (5–10 ppbv) from Asian free troposphere in the upper troposphere over the South Pacific associated with long‐range interhemispheric transport from Asia to the southern midlatitudes (via the western Indian Ocean, Africa, and Atlantic) in the upper troposphere. O3 transported from biomass burning regions such as South America, Africa, and Australia widely distributes in the Southern Hemisphere. Our simulation demonstrates that there is a significant interhemispheric O3 transport from South America to the northern midlatitudes in the upper troposphere which reaches Japan, North Pacific, and the United States in conjunction with O3 export from North Africa. Our tagged O3 simulation estimates that the annual mean global tropospheric O3 burden, as calculated to be 344 Tg in this study, comes from chemical production in the source regions (48%) and in the remote regions (29%) and from stratosphere‐troposphere exchange (23%).
Analytical solution of the depth‐averaged flow velocity in case of submerged rigid cylindrical vegetation
Authors: Huthoff Fredrik , Augustijn Denie C. M. , Hulscher Suzanne J. M. H.
Published: June 2007

A new model for the depth‐averaged velocity for flow in presence of submerged vegetation is developed. The model is based on a two‐layer approach, where flow above and through the vegetation layer is described separately. Vegetation is treated as a homogeneous field of identical cylindrical stems, and the flow field is considered stationary and uniform. It is demonstrated that scaling considerations of the bulk flow field can be used to avoid complications associated with smaller scale flow processes and that still the behavior of depth‐averaged flow over vegetation is described accurately. The derived scaling expression of the average flow field is simple in form, it follows fundamental laws of fluid flow, and it shows very good agreement with laboratory flume experiments. The new model can be used for quick evaluation of a river's hydraulic response in cases where vegetated floodplains are inundated.
Extreme runup from the 17 July 2006 Java tsunami
Authors: Fritz Hermann M. , Kongko Widjo , Moore Andrew , McAdoo Brian , Goff James , Harbitz Carl , Uslu Burak , Kalligeris Nikos , Suteja Debora , Kalsum Kenia , Titov Vasily , Gusman Aditya , Latief Hamzah , Santoso Eko , Sujoko Sungsang , Djulkarnaen Dodi , Sunendar Haris , Synolakis Costas
Published: June 2007

The 17 July 2006 magnitude Mw 7.8 earthquake off the south coast of western Java, Indonesia, generated a tsunami that effected over 300 km of coastline and killed more than 600 people, with locally focused runup heights exceeding 20 m. This slow earthquake was hardly felt on Java, and wind waves breaking masked any preceding withdrawal of the water from the shoreline, making this tsunami difficult to detect before impact. An International Tsunami Survey Team was deployed within one week and the investigation covered more than 600 km of coastline. Measured tsunami heights and run‐up distributions were uniform at 5 to 7 m along 200 km of coast; however there was a pronounced peak on the south coast of Nusa Kambangan, where the tsunami impact carved a sharp trimline in a forest at elevations up to 21 m and 1 km inland. Local flow depth exceeded 8 m along the elevated coastal plain between the beach and the hill slope. We infer that the focused tsunami and runup heights on the island suggest a possible local submarine slump or mass movement.
Model calculations of electron precipitation induced ionization patches on the nightside of Mars
Authors: Fillingim M. O. , Peticolas L. M. , Lillis R. J. , Brain D. A. , Halekas J. S. , Mitchell D. L. , Lin R. P. , Lummerzheim D. , Bougher S. W. , Kirchner D. L.
Published: June 2007

Using an electron transport model, we investigate the effect of electron precipitation on the electron density and total electron content in the nightside ionosphere of Mars. As input we use Mars Global Surveyor observations of a typical tail electron spectrum and an auroral‐like electron spectrum. The accelerated electron spectrum increases the maximum number density and total electron content by a factor of 3 over that produced by the typical tail spectrum. Our calculations show a secondary electron density peak due to precipitation of several keV electrons not seen in previous modeling efforts. Regions of enhanced ionization are expected to be localized in space, corresponding to magnetic cusps formed by the interaction of crustal sources with the interplanetary magnetic field. Radio and radar measurements from both Mars Global Surveyor and Mars Express agree with this expectation. The horizontally inhomogeneous regions of ionization can affect signals used for subsurface sounding from orbit.
Atmosphere‐Ionosphere coupling observed over the dip equatorial MLTI region through the quasi 16‐day wave
Authors: Vineeth C. , Pant Tarun Kumar , Devasia C. V. , Sridharan R.
Published: June 2007

The present paper analyses the variations of daytime mesopause temperature and the Equatorial electrojet strength over the dip equator during December 2005–March 2006 period, indicating a possible strong dynamical coupling between the two region through the intensification of planetary wave activity. The wave signatures (quasi 16‐day period) are seen in the mesopause temperature and the electrojet‐induced surface magnetic field, measured from Trivandrum (8.5°N, 76.5°E, 0.5°N diplat.), a geomagnetic dip equatorial station in India. This investigation reveals (1) amplification of the quasi 16‐day wave in the equatorial mesopause temperature and the EEJ induced magnetic field (2) regular occurrence of Counter Electrojet (CEJ), with a periodicity of ∼16 days (3) diminishing CEJ strength concurrent with the damping of the amplitude of wave oscillation with time. These results are new and reveal some newer aspects of the Mesosphere Lower Thermosphere Ionosphere (MLTI) dynamics.
On the onset of the Gulf of Cadiz Coastal Countercurrent
Authors: Teles‐Machado Ana , Peliz Álvaro , Dubert Jesus , Sánchez Ricardo F.
Published: June 2007

We investigate the onset of the warm counterflow recurrent in summer periods along the shelf of the Gulf of Cadiz and southwest of Iberia. Fully realistic and idealized numerical configurations are used with the aim of partitioning the different processes at play in the complex circulation of the Gulf of Cadiz. The realistic model simulates in great detail an event of warm counterflow in August 2000. The analysis of the idealized and sensitivity experiments allow us to conclude that the counterflow is mainly wind‐driven in response to short but strong Levanter episodes, recurrent after periods of persistent upwelling‐favorable situations.
IL‐3 receptor expression, regulation and function in cells of the Vasculature.
Authors: KORPELAINEN EIJA I , GAMBLE JENNIFER R , VADAS MATHEW A , LOPEZ ANGEL F
Published: June 2007

IL‐3 is a haemopoietic growth factor which stimulates the production and functional activity of various blood cell types. Recent evidence suggests that the target cell population of IL‐3 is not restricted to haemopoietic cells as previously thought, but vascular cells such as endothelial cells also express receptors for and respond to this cytokine. Interestingly, IL‐3 was found to regulate endothelial responses related to inflammation, immunity and haemopoiesis. These findings, summarized in this review, offer new insight into the physiological function of IL‐3 and may also be of clinical importance, as IL‐3 is used in bone marrow reconstitution following cancer therapy.
A comparison of the anti‐idiotypic responses generated by antibodies to a protein and a hapten: A common interspecies idiotype on antibodies against human albumin induces an idiotypic network in rabbits
Authors: COMACCHIO RM , BRADLEY J , HOHMANN AW
Published: June 2007

Idiotypic networks have the capacity to exert significant influences on immune responses and an understanding of the ways to manipulate these networks may lead to new modalities in immunotherapy. In order to gain further insights into the nature of the immune responses stimulated by immunoglobulin idiotypes, rabbits were immunized with a mAb (Ab1) against a large globular protein, human albumin, or a mAb against a hapten, TNP. All rabbits developed anti‐idiotypic antibodies (Ab2) and the rabbits immunized with anti‐human albumin concomitantly developed antibodies to human albumin (Ab3). Ab2 prepared from these rabbits blocked binding of Ab1 to antigen and the anti‐human albumin Ab2 reacted with all species of anti‐human albumin including sheep, rabbit, rat and goat. The anti‐TNP Ab2 reacted only with the mouse anti‐TNP Ab1. This TNP Ab2 bound only to intact Ab1 whereas the human albumin Ab2 reacted with the Ab1 heavy chain. To compare the relative efficiencies of anti‐idiotypic antibodies and antigen in inducing antibody, mice were immunized with rabbit Ab2 or antigen. All mice immunized with Ab2 developed anti‐idiotypic Ab3, but only the human albumin Ab2 preparations elicited antigen specific Ab3; the amount of antibody produced was less than 1% of that found by immunization with antigen. The type of antibody induced in the Ab2‐immunized mice was compared with that found in the antigen‐immunized mice and in the Ab1‐immunized rabbits. The mouse anti‐albumin Ab3 was comparable to mouse Ab1 in terms of affinity and specificity for proteolytic fragments of human albumin. The Ab3 which arose in Ab1‐immunized rabbits had a higher affinity and broader epitope specificity and was similar to antibodies raised against antigen. These results show considerable differences in the ability of similar anti‐idiotypic antibodies to induce immune responses as well as considerable differences in the nature of a response seen within an intact network compared to an artificially induced network.
Manipulation of the helper T cell response to influence antigenic competition occurring with a multivalent vaccine
Authors: HUNT JACQUELINE D , BROWN LORENA E , WOOD PAUL R , STEWART DAVID J , JACKSON DAVID C
Published: June 2007

The reduction in antibody observed following inoculation with multiple heterologous Dichelobacter nodosus pili antigens is thought to be due to competition between antigen‐specific B cells for a limited amount of T cell help. We demonstrate here that this competition is not further influenced by the expansion of cross‐reactive antibody secreting cells at the expense of serogroup specific antibody secreting cells. The T cell determinants of pili recognized by sheep and BALB/c mice have been defined using 15 residue peptides. These T cell determinants include cross‐reactive determinants in the conserved amino terminal region of the antigen. Here we investigate the effect of expanding the pili‐specific T cell population by priming with pili derived T cell determinants. It was not possible to increase the antibody elicited in response to the multivalent vaccine by priming mice with either a synthetic peptide spanning a T cell determinant or with reduced and alkylated or heterologous serogroups of pili 4 weeks before inoculation with the multivalent vaccine. A strategy designed to increase the T cell population by inoculating animals with pili covalently coupled to an extrinsic T cell determinant was pursued.
Polymorphism of IgE gene in chronic urticaria
Authors: PAN K‐Y , WALLS RS , RAJASEKARIAH P , SHERRITT M , WARLOW RS
Published: June 2007

Our aim was to determine whether heterogeneity of the IgE (Cε) gene could be demonstrated in patients with chronic urticaria (CU). We performed Southern blots on DNA extracted from peripheral blood leucocytes of 20 patients with CU and 20 normal controls. Using a human Cε gene probe containing four exons of the constant segment of the IgE heavy chain, we showed the presence of a restriction fragment length polymorphism of the Cε gene segment in four of 20 patients with CU. but in none of 20 normal subjects. Family studies of two propositi revealed the presence of this Cε gene polymorphism in other family members. Our data show that a proportion of patients with CU have a polymorphism of the constant segment of the Cε gene. Further studies of this polymorphic gene fragment indicated that it was derived from duplication of the 3rd and 4th exons of functional Cε gene and was very likely to be located close to this gene. It raises the possibility that polymorphism of the functional Cε gene may affect expression of this gene. This could possibly lead to dysfunctional IgE‐receptor interaction with consequent alteration in mediator release.
Antigen‐Specific apoptosis in immortalized T cells by soluble MHC class II‐peptide complexes
Authors: ARIMILLI SUBHASHINI , MUMM JOHN B , NAG BISHWAJIT
Published: June 2007

The recognition of T cell receptors (TCR) by purified major histocompatibility complex (MHC) class II‐peptide complexes in the absence of costimulatory signals leads to the induction of T cell nonresponsiveness or anergy. In a recent study using human T cell clones, it was observed that prolonged incubation of resting T cells with soluble MHC II‐peptide complexes appears to result in T cell apoptosis. The present study shows that the engagement of TCR by soluble MHC II‐peptide complexes also results in antigen‐specific apoptosis in immortalized T cells. Apoptosis was demonstrated in a herpes saimiri virus (HSV) transformed human T cell clone (SS8T) restricted for HLA‐DR2 in association with an epitope from the myelin basic protein [MBP(84–102)]. A dose‐ and time‐dependent T cell death was observed upon incubation of SS8T cloned T cells with purified complexes of native human HLA‐DR2 and MBP(83–102)Y83 peptide. The specificity of T cell apoptosis was demonstrated by exposing SS8T cells with DR2 alone and DR2 bound to another high affinity epitope [MBP(124–143)] from the same MBP. Recently, we have shown that the complexes of HLA‐DR2 and [MBP(83–102)Y83] can be reconstituted by refolding Escherichia coli expressed individual DR2 a and β (B5*010l) polypeptide chains lacking the transmembrane region. When SS8T cloned T cells were exposed to purified reconstituted rDR2.MBP(83–102)Y83 complexes, similar apoptosis of T cells was observed. Agarose gel analysis of T cells incubated with complexes showed a degradation of celluar deoxyribonucleic acid (DNA) to oligonucleosomal bands, a characteristic of apoptosis. The quantitative detection of DNA strand breaks was performed by pulsing T cells with 5‐bromo‐2′‐deoxyuridine(BrdU) followed by the detection of BrdU‐labelled DNA fragments using an antibody sandwich enzyme‐linked immuno assay (ELISA). The fragmentation of DNA was also measured by double fluorescence flow cytometry by 3′ end labelling of fragmented DNA with biotinylated‐deoxyuridine triphosphate (dUTP) in the presence of terminal deoxynucleotide transferase (TdT) enzyme. The expression of the bel‐2 protein in SS8T cells following TCR engagement by soluble MHC II‐peptide complexes was monitored by chemiluminescence blot analysis using anti‐bel‐2 monoclonal antibody. Finally, the nucleosomal condensation of T cells following complex treatment, characteristics of typical apoptosis, was demonstrated by transmission electron microscopy. These results suggest that the binding of soluble MHC class II‐peptide complexes to TCR induces antigen‐specific apoptosis in transformed CD4 positive T cells in vitro. Such induction of apoptosis by soluble MHC II‐peptide complexes may provide a novel therapeutic strategy to delete autoreactive T cells in various autoimmune diseases.
The monoclonal antibody Mac 387 recognizes three S100 proteins in human neutrophils
Authors: GUIGNARD FLORENCE , MAUËL JACQUES , MARKERT MICHÉLE
Published: June 2007

Mac 387, a murine mAb, was previously described to detect a complex form of MRP‐14 and MRP‐8, two calcium‐binding proteins of the S100 family, but recent experiments suggested that Mac 387 recognized only MRP‐14. Using two‐dimensional polyacrylamide gel electrophoresis and the very sensitive enhanced chemiluminescence detection system, the immunoreactivity of Mac 387 was compared with that of a polyclonal antibody raised against purified MRP‐8. but cross‐reacting with MRP‐14 and p6, a novel S100 protein. Under such conditions, Mac 387 was found to recognize the three S100 proteins. This result suggests that Mac 387 might recognize an epitope common to the proteins of the S100 family.