bluuebunny/crossref_metadata_2025_split huggingface dataset:
Suppression of spontaneous and hydrogen peroxide‐induced mutations by a MutT‐type nucleotide pool sanitization enzyme, the Escherichia coli Orf135 protein
Authors: Kamiya Hiroyuki , Iida Emiko , Murata‐Kamiya Naoko , Yamamoto Yoshihiro , Miki Takeyoshi , Harashima Hideyoshi 
Published: December 2004

AbstractBackground:  We recently found that the Escherichia coli Orf135 protein, a MutT‐type enzyme, hydrolysed 2‐hydroxy‐dATP (2‐OH‐dATP), and less efficiently, 8‐hydroxy‐dGTP.Results:  In this study, we examined the effects of the absence of the orf135 gene. Frequencies of spontaneous and H2O2‐induced mutations were two‐ to three‐fold higher in the orf135‐ strain than in the wild‐type strain. These mutations include various mutations involving a G:C→T:A transversion, the same type of mutation elicited by 2‐OH‐dATP. Over‐expression of the Orf135 protein suppressed mutations even in the wild‐type strain, as well as in the orf135‐ strain.Conclusions:  The mutator phenotype of bacteria lacking the Orf135 protein suggests that this protein is involved in the suppression of mutations induced by oxidized deoxynucleotides in vivo and that various MutT‐type enzymes contribute to nucleotide pool sanitization.
Modelling of GPR waves for lossy media obeying a complex power law of frequency for dielectric permittivity
Authors: Bano Maksim 
Published: December 2004

ABSTRACTThe attenuation of ground‐penetrating radar (GPR) energy in the subsurface decreases and shifts the amplitude spectrum of the radar pulse to lower frequencies (absorption) with increasing traveltime and causes also a distortion of wavelet phase (dispersion). The attenuation is often expressed by the quality factor Q. For GPR studies, Q can be estimated from the ratio of the real part to the imaginary part of the dielectric permittivity.We consider a complex power function of frequency for the dielectric permittivity, and show that this dielectric response corresponds to a frequency‐independent‐Q or simply a constant‐Q model. The phase velocity (dispersion relationship) and the absorption coefficient of electromagnetic waves also obey a frequency power law. This approach is easy to use in the frequency domain and the wave propagation can be described by two parameters only, for example Q and the phase velocity at an arbitrary reference frequency. This simplicity makes it practical for any inversion technique. Furthermore, by using the Hilbert transform relating the velocity and the absorption coefficient (which obeys a frequency power law), we find the same dispersion relationship for the phase velocity. Both approaches are valid for a constant value of Q over a restricted frequency‐bandwidth, and are applicable in a material that is assumed to have no instantaneous dielectric response.Many GPR profiles acquired in a dry aeolian environment have shown a strong reflectivity inside dunes. Changes in water content are believed to be the origin of this reflectivity. We model the radar reflections from the bottom of a dry aeolian dune using the 1D wavelet modelling method. We discuss the choice of the reference wavelet in this modelling approach. A trial‐and‐error match of modelled and observed data was performed to estimate the optimum set of parameters characterizing the materials composing the site. Additionally, by combining the complex refractive index method (CRIM) and/or Topp equations for the bulk permittivity (dielectric constant) of moist sandy soils with a frequency power law for the dielectric response, we introduce them into the expression for the reflection coefficient. Using this method, we can estimate the water content and explain its effect on the reflection coefficient and on wavelet modelling.
Canopy duration has little influence on annual carbon storage in the deciduous broad leaf forest
Authors: WHITE MICHAEL A. , NEMANI RAMAKRISHNA R. 
Published: December 2004

AbstractVegetation phenology, the study of the timing and length of the terrestrial growing season and its connection to climate, is increasingly important in integrated Earth system science. Phenological variability is an excellent barometer of short‐ and long‐term climatic variability, strongly influences surface meteorology, and may influence the carbon cycle. Here, using the 1895–1993 Vegetation/Ecosystem Modelling and Analysis dataset and the Biome‐BGC terrestrial ecosystem model, we investigated the relationship between phenological metrics and annual net ecosystem exchange (NEE) of carbon. For the 1167 deciduous broad leaf forest pixels, we found that NEE was extremely weakly related to canopy duration (days from leaf appearance to complete leaf fall). Longer canopy duration, did, however, sequester more carbon if warm season precipitation was above average. Carbon uptake period (number of days with net CO2 uptake from the atmosphere), which integrates the influence of all ecosystem states and processes, was strongly related to NEE. Results from the Harvard Forest eddy‐covariance site supported our findings. Such dramatically different results from two definitions of ‘growing season length’ highlight the potential for confusion among the many disciplines engaged in phenological research.
Climatic effects on litter decomposition from arctic tundra to tropical rainforest
Authors: LISKI JARI , NISSINEN ARI , ERHARD MARKUS , TASKINEN OLLI 
Published: December 2004

AbstractClimatic effects on the decomposition rates of various litter types in different environments must be known to predict how climatic changes would affect key functions of terrestrial ecosystems, such as nutrient and carbon cycling and plant growth. We developed regression models of the climatic effects on the first‐year mass loss of Scots pine needle litter in boreal and temperate forests across Europe (34 sites), and tested the applicability of these models for other litter types in different ecosystems from arctic tundra to tropical rainforest in Canada (average three year mass loss of 11 litter types at 18 sites), the USA and Central America (four litter types at 26 sites).A temperature variable (annual mean temperature, effective temperature sum or its logarithm) combined with a summer drought indicator (precipitation minus potential evapotranspiration between May and September) explained the first‐year mass loss of the Scots pine needle litter across Europe with a higher R2 value than actual evapotranspiration (0.68–0.74 vs. 0.51) and with less systematic error for any sub‐region. The model with temperature sum and the summer drought indicator appeared best suited to the other litter types and environments. It predicted the climatic effects on the decomposition rates in North and Central America with least systematic error and highest R2 values (0.72–0.80). Compared with Europe, the decomposition rate was significantly less sensitive to annual mean temperature in Canada, and to changes in actual evapotranspiration in the USA and Central America.A simple model distinguishing temperature and drought effects was able to explain the majority of climatic effects on the decomposition rates of the various litter types tested in the varying environments over the large geographical areas. Actual evapotranspiration summarizing the temperature and drought effects was not as general climatic predictor of the decomposition rate.
Six years of in situ CO2 enrichment evoke changes in soil structure and soil biota of nutrient‐poor grassland
Authors: NIKLAUS P. A. , ALPHEI J. , EBERSBERGER D. , KAMPICHLER C. , KANDELER E. , TSCHERKO D. 
Published: December 2004

AbstractNutrient‐poor grassland on a silty clay loam overlying calcareous debris was exposed to elevated CO2 for six growing seasons. The CO2 exchange and productivity were persistently increased throughout the experiment, suggesting increases in soil C inputs. At the same time, elevated CO2 lead to increased soil moisture due to reduced evapotransporation. Measurements related to soil microflora did not indicate increased soil C fluxes under elevated CO2. Microbial biomass, soil basal respiration, and the metabolic quotient for CO2 (qCO2) were not altered significantly. PLFA analysis indicated no significant shift in the ratio of fungi to bacteria. 0.5 m KCl extractable organic C and N, indicators of changed DOC and DON concentrations, also remained unaltered. Microbial grazer populations (protozoa, bacterivorous and fungivorous nematodes, acari and collembola) and root feeding nematodes were not affected by elevated CO2. However, total nematode numbers averaged slightly lower under elevated CO2 (−16%, ns) and nematode mass was significantly reduced (−43%, P = 0.06). This reduction reflected a reduction in large‐diameter nematodes classified as omnivorous and predacious. Elevated CO2 resulted in a shift towards smaller aggregate sizes at both micro‐ and macro‐aggregate scales; this was caused by higher soil moisture under elevated CO2. Reduced aggregate sizes result in reduced pore neck diameters. Locomotion of large‐diameter nematodes depends on the presence of large enough pores; the reduction in aggregate sizes under elevated CO2 may therefore account for the decrease in large nematodes. These animals are relatively high up the soil food web; this decline could therefore trigger top‐down effects on the soil food web. The CO2 enrichment also affected the nitrogen cycle. The N stocks in living plants and surface litter increased at elevated CO2, but N in soil organic matter and microbes remained unaltered. Nitrogen mineralization increased markedly, but microbial N did not differ between CO2 treatments, indicating that net N immobilization rates were unaltered. In summary, this study did not provide evidence that soils and soil microbial communities are affected by increased soil C inputs under elevated CO2. On the contrary, available data (13C tracer data, minirhizotron observations, root ingrowth cores) suggests that soil C inputs did not increase substantially. However, we provide first evidence that elevated CO2 can reduce soil aggregation at the scale from µm to mm scale, and that this can affect soil microfaunal populations.
Three years of free‐air CO2 enrichment (POPFACE) only slightly affect profiles of light and leaf characteristics in closed canopies of Populus
Authors: GIELEN B. , LIBERLOO M. , BOGAERT J. , CALFAPIETRA C. , DE ANGALIS P. , MIGLIETTA F. , SCARASCIA‐MUGNOZZA G. , CEULEMANS R. 
Published: December 2004

AbstractModelling is used to predict long‐term forest responses to increased atmospheric CO2 concentrations. Although productivity models are based on light intercepted by the canopy, very little experimental data are available for closed forest stands. Nevertheless, the relationships between light inside a canopy, leaf area, canopy structure, and individual leaf characteristics may be affected by elevated CO2, affecting in turn carbon gain.Using a free‐air CO2 enrichment (FACE) design in a high‐density plantation of Populus spp., we studied the effects of increased CO2 concentrations on transmittance (τ) of photosynthetic photon flux density (Qp), on ratios of red/far‐red light (R/FR), on leaf area index (LAI), on leaf inclination, on leaf chlorophyll (chl) and nitrogen (N) concentrations, and on specific leaf area (SLA) in the 2nd and 3rd years of treatment. Continuous measurements of τ were made in addition to canopy height profiles of light and leaf characteristics.Two years of Qp measurements showed an average decrease of canopy transmittance in the FACE treatment, with very small differences at canopy closure. Results were explained by an unaffected LAI in closed canopies, without a FACE‐induced stimulation of relative crown depth. In agreement, leaf inclination and extinction coefficients for light were similar in control and FACE conditions. Ratios of R/FR were not significantly affected by the FACE treatment, neither were leaf characteristics, with the exception of leaf N, which allows speculation about N limitation. In general, treatment differences in canopy profiles resulted from an initial stimulation of height growth in the FACE treatment. P. × euramericana differed from P. alba and P. nigra, but species did not differ significantly in their response to the FACE treatment. By the time fast‐growing high‐density forest plantations have passed the exponential growth phase and reached canopy closure, the likely effects of elevated atmospheric CO2 concentration on canopy architecture and absorption of Qp are minor.
Elevated CO2 and temperature alter nitrogen allocation in Douglas‐fir
Authors: TINGEY DAVID T. , MCKANE ROBERT B. , OLSZYK DAVID M. , JOHNSON MARK G. , RYGIEWICZ PAUL T. , HENRY LEE E. 
Published: December 2004

AbstractThe effects of elevated CO2 and temperature on principal carbon constituents (PCC) and C and N allocation between needle, woody (stem and branches) and root tissue of Pseudotsuga menziesii Mirb. Franco seedlings were determined. The seedlings were grown in sun‐lit controlled‐environment chambers that contained a native soil. Chambers were controlled to reproduce ambient or ambient +180 ppm CO2 and either ambient temperature or ambient +3.5 °C for 4 years. There were no significant CO2 × temperature interactions; consequently the data are presented for the CO2 and temperature effects. At the final harvest, elevated CO2 decreased the nonpolar fraction of the PCC and increased the polar fraction and amount of sugars in the needles. In contrast, elevated temperature increased the nonpolar fraction of the PCC and decreased sugars in needles. There were no CO2 or temperature effects on the PCC fractions in the woody tissue or root tissue. Elevated CO2 and temperature had no significant effects on the C content of any of the plant tissues or fractions. In contrast, the foliar N content declined under elevated CO2 and increased under elevated temperature; there were no significant effects in other tissues. The changes in the foliar N concentrations were in the cellulose and lignin fractions, the fractions, which contain protein, and are the consequences of changes in N allocation under the treatments. These results indicate reallocation of N among plant organs to optimize C assimilation, which is mediated via changes in the selectivity of Rubisco and carbohydrate modulation of gene expression.
Super‐optimal temperatures are detrimental to peanut (Arachis hypogaea L.) reproductive processes and yield at both ambient and elevated carbon dioxide
Authors: Vara Prasad P. V. , Boote Kenneth J. , Hartwell Allen L. , Thomas Jean M. G. 
Published: December 2004

AbstractContinuing increases in atmospheric carbon dioxide concentration (CO2) will likely be accompanied by global warming. Our research objectives were (a) to determine the effects of season‐long exposure to daytime maximum/nighttime minimum temperatures of 32/22, 36/26, 40/30 and 44/34°C at ambient (350 μmol mol−1) and elevated (700 μmol mol−1) CO2 on reproductive processes and yield of peanut, and (b) to evaluate whether the higher photosynthetic rates and vegetative growth at elevated CO2 will negate the detrimental effects of high temperature on reproductive processes and yield. Doubling of CO2 increased leaf photosynthesis and seed yield by 27% and 30%, respectively, averaged across all temperatures. There were no effects of elevated CO2 on pollen viability, seed‐set, seed number per pod, seed size, harvest index or shelling percentage. At ambient CO2, seed yield decreased progressively by 14%, 59% and 90% as temperature increased from 32/22 to 36/26, 40/30 and 44/34°C, respectively. Similar percentage decreases in seed yield occurred at temperatures above 32/22°C at elevated CO2 despite greater photosynthesis and vegetative growth. Decreased seed yields at high temperature were a result of lower seed‐set due to poor pollen viability, and smaller seed size due to decreased seed growth rates and decreased shelling percentages. Seed harvest index decreased from 0.41 to 0.05 as temperature increased from 32/22 to 44/34°C under both ambient and elevated CO2. We conclude that there are no beneficial interactions between elevated CO2 and temperature, and that seed yield of peanut will decrease under future warmer climates, particularly in regions where present temperatures are near or above optimum.
Acquired inhibitor against factor IX in a child: successful treatment with high‐dose immunoglobulin and dexamethasone
Authors: MAZZUCCONI M. G. , PERAINO M. , BIZZONI L. , BERNASCONI S. , LUCIANI M. , ROSSI G. DE 
Published: December 2004

The occurrence of acquired inhibitor against factor IX:C is infrequent in haemophilia B patients and is very rare in previously healthy subjects, in whom it is often related to underlying diseases.We describe the case of a 2‐year‐old girl, who was referred to our hospital with haematomas, without previous bleeding history. Prolonged APTT, normal PT and a factor IX:C level below 1% were found. An inhibitor against factor IX:C was detected (5.5 U mL−1). Her father and mother showed normal factor IX:C levels. Treatment with high‐dose immunoglobulin (400 mg kg−1 day−1 for 5 consecutive days by intravenous infusion) and dexamethasone (4 mg three times a day by intravenous injection for 4 consecutive days) normalized factor IX:C levels and overcame the inhibitor.In conclusion, high‐dose immunoglobulin and high‐dose dexamethasone are a successful and safe immunosuppressive approach for recovery from inhibitor occurrence.
The treatment of flexion contracture of the knee using the Ilizarov technique in a child with haemophilia B
Authors: Kiely P. D. , McMahon C. , Smith O. P. , Moore D. P. 
Published: December 2004

Summary.  Severe factor IX deficiency is an X‐linked disorder which gives rise to spontaneous and often life‐threatening bleeds. The major source of morbidity worldwide is recurrent haemarthroses, giving rise to joint destruction and deformity. However, the incidence of spontaneous haemarthroses has decreased since the advent of prophylactic home‐based, on‐demand, early replacement therapy.We present the case of a non‐ambulant, 13‐year‐old boy from Chernobyl, who did not have access to this type of treatment, and whose deformity was managed using the Ilizarov external fixator.An external fixator was applied under general anaesthetic in theatre. Haemostasis was achieved by maintaining his FIX levels at 1.0 IU mL−1 pre‐ and post‐operatively. Three months later, the fixed flexion deformity had been reduced from 50 to 5°. Four months postsurgery, this boy was walking freely without pain. There was no peri‐ or post‐operative bleeding or joint swelling.
Immune tolerance therapy dose as an outcome predictor
Authors: DiMichele Donna 
Published: December 2004

Summary.  The question of dose as a successful ITT outcome predictor in haemophilia A and B is an important one on many levels. Increased morbidity associated with inhibitor development has been documented [3]. Currently, immune tolerance is the only proven method for inhibitor eradication. Furthermore, given the morbidity and the high cost of less effective bypass therapy, a study by Harvard health economists using Markov decision analysis predicted an increased life expectancy of 4.5 years at a lifetime cost savings of $1.6 million with the use of ITT rather than lifelong APCC therapy [25].However, the immediate short‐term cost of this expensive therapeutic intervention has the capacity to strain the financial resources of many countries in the developed world, regardless of the system of medical reimbursement. It also assures the inaccessibility of this treatment modality to most of the world's inhibitor patients living in the developing world. Cost aside, recent experience has taught us that clotting factor supply is precarious, not inexhaustible as previously assumed. Finally, in the paediatric patient who is most likely to require and undergo ITT, venous access for daily infusions is problematic with or without a central venous access device. Indeed, for these reasons alone, finding the answer to the question of optimal cost‐effective dosing immune tolerance is a matter of medical urgency and moral obligation to the global haemophilia community.
Management of haemophilia B inhibitor patients with anaphylactic reactions to FIX concentrates
Authors: Shibata M. , Shima M. , Misu H. , Okimoto Y. , Giddings J. C. , Yoshioka A. 
Published: December 2004

Summary. Allergic reactions to concentrates containing factor IX (FIX) are serious complications in the treatment of haemophilia B patients with inhibitor. We have established a therapeutic protocol for such cases using an initial skin test followed by step‐wise infusions of FIX concentrates under hydrocortisone cover. We have successfully treated three patients whose treatment with FIX had been suspended.
Immune tolerance induction in patients with haemophilia A with inhibitors: a systematic review
Authors: Wight J. , Paisley S. , Knight C. 
Published: December 2004

Summary.  In some patients with haemophilia A, therapeutically administered factor VIII (FVIII) comes to stimulate the production of antibodies (inhibitors) which react with FVIII to render it ineffective. As a result, FVIII cannot be used prophylactically and patients become liable to recurrent bleeds. There are two elements to the management of patients with inhibitors: the treatment of bleeding episodes, and attempts to abolish inhibitor production through the induction of immune tolerance.This paper reports a systematic review of the best available evidence of clinical effectiveness in relation to immune tolerance induction (ITI) in patients with haemophilia A with inhibitors. Owing to the lack of randomized controlled trials on this topic, broad inclusion criteria with regard to study design were applied in order to assess the best available evidence for each intervention. As a result of the clinical and methodological heterogeneity of the evidence, it was not appropriate to pool data across studies; instead, data were synthesized using tabulation and qualitative narrative assessment.The International Registry provides the most reliable estimate of the proportion of successful cases of ITI [48.7%, 95% confidence interval (CI) 42.6–52.7%]. The duration of effect is unclear, but relapses appear to be infrequent. The International Registry shows a rate of relapse of 15% at 15 years. The comparative effectiveness of different protocols is uncertain, as no trials have been undertaken which compare them directly. However, the evidence suggests that the Bonn protocol may be more effective than the Malmö or low‐dose protocols. There is no good evidence that immunosuppressive drug regimens are effective.
Redesigning mental health services: lessons on user involvement from the Mental Health Collaborative
Authors: Robert Glenn , Hardacre Jeanne , Locock Louise , Bate Paul , Glasby Jon 
Published: December 2004

AbstractObjectives  To explore the involvement of mental health service users in the redesign of in‐patient mental health services in six Trusts participating in a multi‐regional NHS modernization programme.Design  Semi‐structured interviews and observation of team meetings undertaken as part of an action research study.Participants and setting  Users, clinical, medical and managerial staff from six mental health trusts which participated in the Northern & Yorkshire and Trent regions’ Mental Health Collaborative (MHC).Results and conclusions  Whilst there were some problems, user involvement was undoubtedly a strength of the MHC in comparison to other modernization programmes within the NHS we have studied. However, the particular challenges posed by the specific context of acute mental health services should not be overlooked. The initial approach taken in each of the sites was to simply invite a user or user representative to join the local project team. In the course of events, various changes were made to this initial mechanism for involving users in the ongoing work of the teams. These changes – and setbacks in some sites – make drawing firm conclusions as to the effectiveness of the various strategies employed problematic. However, our qualitative data suggest a number of broad lessons that will assist both those leading and participating in other redesign initiatives to maximize the benefits to be gained from service user involvement.