bluuebunny/crossref_metadata_2025_split huggingface dataset:
Intercellular adhesion and cell separation in plants
Authors: JARVIS M. C. , BRIGGS S. P. H. , KNOX J. P. 
Published: July 2003

ABSTRACTAdhesion between plant cells is a fundamental feature of plant growth and development, and an essential part of the strategy by which growing plants achieve mechanical strength. Turgor pressure provides non‐woody plant tissues with mechanical rigidity and the driving force for growth, but at the same time it generates large forces tending to separate cells. These are resisted by reinforcing zones located precisely at the points of maximum stress. In dicots the reinforcing zones are occupied by networks of specific pectic polymers. The mechanisms by which these networks cohere vary and are not fully understood. In the Poaceae their place is taken by phenolic cross‐linking of arabinoxylans. Whatever the reinforcing polymers, a targeting mechanism is necessary to ensure that they become immobilized at the appropriate location, and there are secretory mutants that appear to have defects in this mechanism and hence are defective in cell adhesion. At the outer surface of most plant parts, the tendency of cells to cohere is blocked, apparently by the cuticle. Mutants with lesions in the biosynthesis of cuticular lipids show aberrant surface adhesion and other developmental abnormalities. When plant cells separate, the polymer networks that join them are locally dismantled with surgical precision. This occurs during the development of intercellular spaces; during the abscission of leaves and floral organs; during the release of seeds and pollen; during differentiation of root cap cells; and during fruit ripening. Each of these cell separation processes has its own distinctive features. Cell separation can also be induced during cooking or processing of fruit and vegetables, and the degree to which it occurs is a significant quality characteristic in potatoes, pulses, tomatoes, apples and other fruit. Control over these technological characteristics will be facilitated by understanding the role of cell adhesion and separation in the life of plants.
Identification of regulatory sequence elements within the transcription promoter region of NpABC1, a gene encoding a plant ABC transporter induced by diterpenes
Authors: Grec Sébastien , Vanham Delphine , De Ribaucourt Jeoffrey Christyn , Purnelle Bénédicte , Boutry Marc 
Published: July 2003

SummaryExpression of NpABC1, a gene encoding a plasma membrane ATP binding cassette (ABC) transporter in Nicotiana plumbaginifolia, is induced by sclareol, an antifungal diterpene produced at the leaf surface, as well as by sclareolide, a close analog. A genomic fragment including the 1282‐bp region upstream of the NpABC1 transcription start was fused to the reporter β‐glucuronidase (gus) gene and introduced into N. tabacum BY2 cells for stable transformation. A 25‐fold increase in gus expression was observed when cells were treated with sclareolide and some other terpenes. The combined use of 5′‐deletion promoter analysis, gel mobility shift assays, DNase I footprinting, and site‐directed mutagenesis allowed us to identify three cis‐elements (sclareol box 1 (SB1), SB2, and SB3) located, respectively, within nucleotides −827 to −802, −278 to −243, and −216 to −190 upstream of the NpABC1 transcription start. In vivo evaluation of these elements on sclareolide‐induced expression showed that mutation of SB1 reduced expression by twofold, while that of SB2 had no effect. On the other hand, SB3 had a marked effect as it completely abolished sclareolide‐mediated expression. NpABC1‐gus expression was not induced by the stress signals, salicylic acid and ethylene, but was mediated, to some extent, by methyl jasmonate, which is known to promote diterpene synthesis.
Arabidopsis local resistance to Botrytis cinerea involves salicylic acid and camalexin and requires EDS4 and PAD2, but not SID2, EDS5 or PAD4
Authors: Ferrari Simone , Plotnikova Julia M. , De Lorenzo Giulia , Ausubel Frederick M. 
Published: July 2003

SummarySalicylic acid (SA) is an important regulator of plant defense responses, and a variety of Arabidopsis mutants impaired in resistance against bacterial and fungal pathogens show defects in SA accumulation, perception, or signal transduction. Nevertheless, the role of SA‐dependent defense responses against necrotrophic fungi is currently unclear. We determined the susceptibility of a set of previously identified Arabidopsis mutants impaired in defense responses to the necrotrophic fungal pathogen Botrytis cinerea. The rate of development of B. cinerea disease symptoms on primary infected leaves was affected by responses mediated by the genes EIN2, JAR1, EDS4, PAD2, and PAD3, but was largely independent of EDS5, SID2/ICS1, and PAD4. Furthermore, plants expressing a nahG transgene or treated with a phenylalanine ammonia lyase (PAL) inhibitor showed enhanced symptoms, suggesting that SA synthesized via PAL, and not via isochorismate synthase (ICS), mediates lesion development. In addition, the degree of lesion development did not correlate with defensin or PR1 expression, although it was partially dependent upon camalexin accumulation. Although npr1 mutant leaves were normally susceptible to B. cinerea infection, a double ein2 npr1 mutant was significantly more susceptible than ein2 plants, and exogenous application of SA decreased B. cinerea lesion size through an NPR1‐dependent mechanism that could be mimicked by the cpr1 mutation. These data indicate that local resistance to B. cinerea requires ethylene‐, jasmonate‐, and SA‐mediated signaling, that the SA affecting this resistance does not require ICS1 and is likely synthesized via PAL, and that camalexin limits lesion development.
Capital Flows, Interest Payments and the Balance‐of‐Payments Constrained Growth Model: A Theoretical and Empirical Analysis
Authors: Moreno‐Brid Juan Carlos 
Published: July 2003

The analytical framework known as the balance‐of‐payments constrained growth model introduced by Anthony P. Thirlwall more than two decades ago, and further developed by him and N. Hussain, was a major contribution to understanding the relevance of a foreign exchange constraint on the long‐run growth performance of open economies. In its simplest expression this model is known as Thirlwall's law. Recent contributions have revised this analytical model in order to ensure that the pattern of foreign debt accumulation, implicit in the economy's balance‐of‐payments constrained growth path, is sustainable.Up to now most theoretical presentations of Thirlwall's law do not incorporate interest payments explicitly and, moreover, the empirical studies carried out within this tradition do not take them into account. This omission may be a major shortcoming in the analysis of the long‐term growth path of economies—like many developing ones—whose net interest payments abroad are a large debit item in the current account of their balance of payments. In the present paper we introduce an extension of the balance‐of‐payments constrained growth model that explicitly captures the influence on foreign interest payments of the economy's long‐run rate of growth—while at the same time guaranteeing that foreign indebtedness is not on an explosive track—and test its empirical adequacy by applying it to examine the Mexican case.
The Measurement of Low Pay in the UK Labour Force Survey*
Authors: Skinner Chris , Stuttard Nigel , Beissel‐Durrant Gabriele , Jenkins James 
Published: July 2003

AbstractConsideration of the National Minimum Wage requires estimates of the distribution of hourly pay. The UK Labour Force Survey (LFS) is a key source of such estimates. The approach most frequently adopted by researchers has been to measure hourly earnings from several questions on pay and hours. The Office for National Statistics is now applying a new approach, based on an alternative more direct measurement introduced in March 1999. These two measures do not produce identical values and this paper investigates sources of discrepancies and concludes that the new variable is more accurate. The difficulty with using the new variable is that it is only available on a subset of respondents. An approach is developed in which missing values of the new variable are replaced by imputed values. The assumptions underlying this imputation approach and results of applying it to LFS data are presented. The relation to weighting approaches is also discussed.
Endothelial Cells Are Main Producers of Interleukin 8 through Toll-Like Receptor 2 and 4 Signaling during Bacterial Infection in Leukopenic Cancer Patients
Authors: Oude Nijhuis C. S. M. , Vellenga E. , Daenen S. M. G. J. , Kamps W. A. , de Bont E. S. J. M. 
Published: July 2003

ABSTRACTCancer patients who are leukopenic due to chemotherapy are susceptible to bacterial infections. Normally, clinical conditions during bacterial infections are caused by pathogen-associated molecular patterns, which are components that bind to Toll-like receptor (TLR) 2 (TLR-2) and TLR-4 on leukocytes, resulting in the production of inflammatory cytokines. The mechanism of this inflammatory response in cancer patients with diminished numbers of leukocytes is not completely clear. The levels of interleukin 1β (IL-1β) and tumor necrosis factor alpha measured in the circulation of leukopenic cancer patients are lower than those measured in that of nonleukopenic patients during bacterial infections, whereas plasma interleukin 8 (IL-8) levels show distinct identical increases during bacterial infections in both leukopenic and nonleukopenic patients. Normally, these cytokines are mainly secreted by leukocytes. In cancer patients with bacterial infections and a diminished number of leukocytes, other sources of IL-8 production, such as endothelial cells, might be expected. Endothelial cells instead of leukocytes become the most important producers of IL-8 during bacterial infections in patients with chemotherapy-induced leukopenia through TLR-2 and TLR-4 signaling. Whole blood samples from six cancer patients were stimulated with lipopolysaccharide (LPS), and then IL-8 concentrations in supernatants were measured. Further, human umbilical vein endothelial cells (HUVECs) were incubated with sera from leukopenic cancer patients with or without bacterial infections, and then IL-8 concentrations in supernatants were measured (n= 6). In addition, the same HUVEC experiment was performed with the addition of neutralizing antibodies against TLR-2 and TLR-4. During leukopenia (<109cells/liter), LPS stimulation of whole blood did not result in an increase in IL-8 levels. However, when endothelial cells were incubated with sera from leukopenic cancer patients during bacterial infections, a three- to eightfold increase in IL-8 production was found, compared to the IL-8 production found after incubation with sera from patients without signs of infections. This increase did not reflect a higher level of IL-8 already present in the sera. Further, we demonstrated that IL-8 production induced in endothelial cells by sera from patients with documented gram-negative infections could be reduced significantly by up to 40% when the cells were incubated with neutralizing antibodies against TLR-4 (P= 0.028). The addition of TLR-2 antibodies slightly enhanced the reduction of IL-8 production. These results suggest that during bacterial infections in cancer patients with markedly diminished numbers of leukocytes, endothelial cells become important producers of IL-8 through TLR-4 signaling and, to a lesser extent, TLR-2 signaling.
Use of Mouse Models To Evaluate the Persistence, Safety, and Immune Modulation Capacities of Lactic Acid Bacteria
Authors: Pavan Sonia , Desreumaux Pierre , Mercenier Annick 
Published: July 2003

ABSTRACT

Recent clinical and experimental observations showed that specific probiotic microorganisms may provide therapeutic benefits in inflammatory bowel disease. However, a rigorous screening for new candidate probiotic strains with optimized therapeutic properties necessitates also determining possible adverse interactions with the host, particularly in individuals who are not healthy. We have evaluated the persistence of strains of lactic acid bacteria (LAB) in the digestive tracts of mice, their immunomodulation capacity, and their safety in healthy animals and in a colitis model. Following daily administration of 10
9
CFU of viable LAB orally, intragastrically, or intrarectally, the animals' feces were examined for bacterial excretion and cytokines were quantified in intestinal samples by quantitative reverse transcription-PCR. The level of bacterial translocation was assessed in healthy mice and in mice suffering from colitis induced by 2,4,6-trinitrobenzene sulfonic acid (TNBS). Irrespective of the route of administration, the potential probiotic strain
Lactobacillus plantarum
NCIMB8826 was found to persist for up to 10 days in the digestive tracts of mice. This strain did not induce detrimental effects in healthy or in TNBS-treated animals, as was reflected by the absence of weight loss, intestinal inflammation, modification of cytokine levels in the ileum and colon (healthy mice), and bacterial dissemination (healthy and colitic animals). Moreover, the translocation of endogenous microflora to the mesenteric lymph nodes and spleen was greatly reduced in the TNBS-treated mice after administration of LAB. This property, together with the strain's persistence capacity and innocuousness renders
L. plantarum
NCIMB8826 an attractive candidate as a probiotic to be used in the prevention or treatment of chronic inflammation.
Systemic Inflammatory Responses in Children with Acute Otitis Media Due toStreptococcus pneumoniaeand the Impact of Treatment with Clarithromycin
Authors: Scharer Gunter , Zaldivar Frank , Gonzalez Guillermo , Vargas-Shiraishi Ofelia , Singh Jasjit , Arrieta Antonio 
Published: July 2003

ABSTRACTThis pilot study was designed to determine the serum cytokine profile of acute otitis media (AOM) due toStreptococcus pneumoniaeand the impact of clarithromycin (Abbott Laboratories, Inc). Serum levels of interleukin-1β (IL-1β), tumor necrosis factor alpha (TNF-α), IL-6, and IL-8 were measured at diagnosis and 3 to 5 days after start of antibiotic treatment in 10 patients (mean age, 18.3 ± 13.9 months) who had middle ear fluid culture positive forS. pneumoniae.The mean concentrations of all cytokines were elevated at diagnosis of AOM compared to levels in healthy controls, yet only IL-6 reached statistical significance (P= 0.05). IL-6 showed a statistically significant decrease in mean serum concentration at visit 2 (P= 0.03). IL-8 displayed a similar pattern to IL-6, but the difference between samples from day 1 and day 2 did not reach statistical significance. The cytokines IL-1β and TNF-α appear to be elevated in the serum of patients withS. pneumoniaeAOM, but there was no significant change between mean serum levels obtained pre- and postinitiation of antibiotic treatment in the time frame studied. The results suggest a systemic inflammatory response as evidenced by increased IL-6. A significant decrease of IL-6 and improvement of clinical symptoms were observed. Determining cytokine levels, especially IL-6, in AOM could offer a powerful tool for objective assessment of response to treatment, minimizing unnecessary treatment of asymptomatic children who may still have some otoscopic findings suggestive of AOM at follow-up visits.
End‐of‐Life Infrastructure Economics for “Clean Vehicles” in the United States
Authors: Boon Jane E. , Isaacs Jacqueline A. , Gupta Surendra M. 
Published: July 2003

SummaryRising fuel prices and concern over emissions are prompting automakers and legislators to introduce and evaluate “clean vehicles” throughout the United States. Hybrid electric vehicles (HEVs) are now on the roads, electric vehicles (EVs) have been test marketed, and niche vehicles such as high‐fuel‐economy microcars are being considered for introduction. As these vehicles proliferate and mature, they will eventually reach their end of life (EOL). In the United States, an extensive recycling infrastructure exists for conventional, internal combustion engine (ICE) vehicles. Its primary constituents are the disassembler and the shredder. These industries, as well as battery recyclers, are expected to play integral roles in the EOL processing of clean vehicles.A model of the automobile‐recycling infrastructure and goal programming techniques are used to assess the materials streams and process profitabilities for several different clean vehicles. Two‐seat EVs with lead‐acid or NiMH batteries are compared with two‐ and four‐seat HEVs and microcars. Changes to the nonferrous content in the vehicle bodies are explored and compared for the effect on processing profit‐ability. Despite limitations associated with the linearity of goal programming techniques, application of this tool can still provide informative first‐order results. Results indicate that although these clean vehicles may not garner the same profit levels as conventional ICE vehicles, they are profitable to process if there are markets for parts and if there are sufficient quantities of nonferrous materials.
Seasonal Contrasting Features of Heat and Moisture Budgets between the Eastern and Western Tibetan Plateau during the GAME IOP
Authors: Ueda Hiroaki , Kamahori Hirotaka , Yamazaki Nobuo 
Published: July 2003

Abstract
Using the Global Energy and Water Cycle Experiment (GEWEX) Asian Monsoon Experiment (GAME) four-dimensional data assimilation (4DDA) upper-air data, the large-scale heat source (Q1) and moisture sink (Q2) over the western and eastern Tibetan Plateau are examined for a 4-month period from 1 May to 31 August 1998. The computations were performed on the sigma–pressure hybrid coordinate, named η-coordinate, since the analysis area includes high-elevation mountains.
Over the western Tibetan Plateau in May, there is a deep layer of heating occupying the whole troposphere with the maximum value exceeding 3 K day−1 around 400–600 hPa. The smaller magnitude of the apparent moisture sink is confined in the lower troposphere 1 km above the ground surface. Vertically integrated heat sources of 103 W m−2 over the western Tibetan Plateau are accompanied by a moisture sink of about half that (60 W m−2). These results indicate that the latent heat release associated with condensation plays an important role in the total heating besides the sensible heat supply from the land surface. Later in July, the moisture sink over the eastern Tibetan Plateau nearly equals the heat source indicating the dominance of moist processes associated with summertime monsoon rains.
The contrasting features of the heat source and moisture sink are closely related to the circulation fields. Throughout May and June, we observe strong upward motion along the western and southwestern slopes of the western Tibetan Plateau, while there is salient subsidence motion over the eastern Tibetan Plateau. The analyses of static stability and lifting condensation level indicate that the release of latent heat relevant to moist convection is a dominant factor for tropospheric heating after the monsoon onset, while the premonsoon period (May) is composed of both convective rainfall and dry thermal convection.
Thus, the heating mechanism prior to the onset of the monsoon, especially over the western Tibetan Plateau, can be characterized by the hybrid nature of “wet” processes due to condensation heating and “dry” processes associated with the sensible heat flux from the elevated mountain surface.
Intensity of Hydrological Cycles in Warmer Climates
Authors: Yang Fanglin , Kumar Arun , Schlesinger Michael E. , Wang Wanqiu 
Published: July 2003

Abstract
The fact that the surface and tropospheric temperatures increase with increasing CO2 has been well documented by numerical model simulations; however, less agreement is found for the changes in the intensity of precipitation and the hydrological cycle. Here, it is demonstrated that while both the radiative heating by increasing CO2 and the resulting higher sea surface temperatures contribute to warm the atmosphere, they act against each other in changing the hydrological cycle. As a consequence, in a warmer climate forced by increasing CO2 the intensity of the hydrological cycle can be either more or less intense depending upon the degree of surface warming.
Observations of SST-Induced Perturbations of the Wind Stress Field over the Southern Ocean on Seasonal Timescales
Authors: O'Neill Larry W. , Chelton Dudley B. , Esbensen Steven K. 
Published: July 2003

Abstract
The surface wind stress response to sea surface temperature (SST) over the latitude range 30°–60°S in the Southern Ocean is described from the National Aeronautics and Space Administration's QuikSCAT scatterometer observations of wind stress and Reynolds analyses of SST during the 2-yr period August 1999 to July 2001. While ocean–atmosphere coupling at midlatitudes has previously been documented from several case studies, this is the first study to quantify this relation over the entire Southern Ocean. The spatial structures of the surface wind perturbations with wavelengths shorter than 10° latitude by 30° longitude are closely related to persistent spatial variations of the SST field on the same scales. The wind stress curl and divergence are shown to be linearly related, respectively, to the crosswind and downwind components of the SST gradient. The curl response has a magnitude only about half that of the divergence response. This observed coupling is consistent with the hypothesis that SST modification of marine atmospheric boundary layer (MABL) stability affects vertical turbulent mixing of momentum, inducing perturbations in the surface winds. The nonequivalence between the responses of the curl and divergence to the crosswind and downwind SST gradients suggests that secondary circulations in the MABL may also play an important role by producing significant perturbations in the surface wind field near SST fronts that are distinct from the vertical turbulent transfer of momentum. The importance of the wind stress curl in driving Ekman vertical velocity in the open ocean implies that the coupling between winds and SST may have important feedback effects on upper ocean processes near SST fronts.
Continuous Fiber Reinforced Titanium Matrix Composites: Fabrication, Properties, and Applications
Authors: Leyens C. , Hausmann J. , Kumpfert J. 
Published: July 2003

AbstractTitanium matrix composites (TMCs) have been developed as high performance materials for light weight structural applications. The materials are comprised of a silicon carbide (SiC) fiber embedded in a titanium matrix, thus making use of the high strength of the SiC fibers, their high stiffness and creep resistance at elevated temperatures combined with the damage tolerance of titanium alloys. Since materials properties are closely related to the quality of the fabrication process, TMC processing is of major importance. Moreover, reinforcement‐induced anisotropy of the material and thermal residual stresses formed during the consolidation process must be considered and understood for proper component design. Finally, modeling using FE methods reduces the time needed for component development and helps to elucidate failure mechanisms of the material.