bluuebunny/crossref_metadata_2025 huggingface dataset:
Dissection of the GTPase mechanism of Ras protein by MD analysis of Ras mutants
Authors: Friedman Zeev Y. , Devary Yoram
Published: March 2005

Controlling the hydrolysis rate of GTP bound to the p21ras protein is crucial for the delicate timing of many biological processes. A few mechanisms were suggested for the hydrolysis of GTP. To gain more insight into the individual elementary events of GTP hydrolysis, we carried out molecular dynamic analysis of wild‐type p21ras and some of its mutants. It was recently shown that Ras‐related proteins and mutants generally follow a linear free energy relationship (LFER) relating the rate of reaction to the pKa of the γ‐phosphate group of the bound GTP, indicating that proton transfer from the attacking water to the GTP is the first elementary event in the GTPase mechanism. However, some exceptions were observed. Thus, the Gly12 → Aspartic p21ras (G12D) mutant had a very low GTPase activity although its pKa was very close to that of the wild‐type ras. Here we compared the molecular dynamics (MD) of wild‐type Ras and G12D, showing that in the mutant the catalytic water molecule is displaced to a position where proton transfer to GTP is unfavorable. These results suggest that the mechanism of GTPase is indeed composed of an initial proton abstraction from water by the GTP, followed by a nucleophilic attack of the hydroxide ion on the γ‐phosphorus of GTP. Proteins 2005. © 2005 Wiley‐Liss, Inc.
Structural analysis of interactions for complex formation between Ferredoxin‐NADP+ reductase and its protein partners
Authors: Mayoral Tomás , Martínez‐Júlvez Marta , Pérez‐Dorado Inmaculada , Sanz‐Aparicio Julia , Gómez‐Moreno Carlos , Medina Milagros , Hermoso Juan A.
Published: March 2005

The three‐dimensional structures of K72E, K75R, K75S, K75Q, and K75E Anabaena Ferredoxin‐NADP+ reductase (FNR) mutants have been solved, and particular structural details of these mutants have been used to assess the role played by residues 72 and 75 in optimal complex formation and electron transfer (ET) between FNR and its protein redox partners Ferredoxin (Fd) and Flavodoxin (Fld). Additionally, because there is no structural information available on the interaction between FNR and Fld, a model for the FNR:Fld complex has also been produced based on the previously reported crystal structures and on that of the rat Cytochrome P450 reductase (CPR), onto which FNR and Fld have been structurally aligned, and those reported for the Anabaena and maize FNR:Fd complexes. The model suggests putative electrostatic and hydrophobic interactions between residues on the FNR and Fld surfaces at the complex interface and provides an adequate orientation and distance between the FAD and FMN redox centers for efficient ET without the presence of any other molecule as electron carrier. Thus, the models now available for the FNR:Fd and FNR:Fld interactions and the structures presented here for the mutants at K72 and K75 in Anabaena FNR have been evaluated in light of previous biochemical data. These structures confirm the key participation of residue K75 and K72 in complex formation with both Fd and Fld. The drastic effect in FNR activity produced by replacement of K75 by Glu in the K75E FNR variant is explained not only by the observed changes in the charge distribution on the surface of the K75E FNR mutant, but also by the formation of a salt bridge interaction between E75 and K72 that simultaneously “neutralizes” two essential positive charged side chains for Fld/Fd recognition. Proteins 2005. © 2005 Wiley‐Liss, Inc.
Unique Bridging Function of the Triazole Core in Copper(II) Chloride Complexes with 1‐Allylbenzotriazole
Authors: Goreshnik E. A. , Schollmeyer D. , Mys'kiv M. G.
Published: March 2005

During alternating‐current electrochemical synthesis of copper(I) π‐complex of [CuCl{C6H4N3(C3H5)}] composition, starting from ethanol solution, containing CuCl2·2H2O and 1‐allylbenzotriazole, green crystals of intermediate [CuII3Cl6{C6H4N3(C3H5)}4] (I) compound has been obtained upon 24 h. After some days these crystals transform into red ones of [CuII2Cl4{C6H4N3(C3H5)}3] (II). Both compounds were X‐Ray structurally investigated. Crystals of I are triclinic, sp.gr. ${\rm P}{\bar 1}$ a = 9.1329(9), b = 10.0352(4), c = 12.239(3) Å, α = 76.443(13), β = 84.470(14), γ = 76.808(7)°, V = 1060.5(3) Å3, R = 0.0414 for 3311 reflections. II: monoclinic, C2/c, a = 13.828(1), b = 15.044(2), c = 10.702(1) Å, β = 91.36(1)°, V = 2225.7(4) Å3, R = 0.050 for 1495 reflections. In both compounds each benzotriazole core coordinates two copper atoms using two nitrogen atoms in 2 and 3 positions. Isolated Cu3Cl6 fragments in I are condensed along [001] direction into infinite chains [CuCl2]n in II. Finally, red crystals of II transform into colorless ones of the earlier studied copper(I) π‐complex of CuCl·C6H4N3(C3H5) composition.
CCK-Containing paraneurons in human adenomatous prostate
Authors: Cecio A. , Cocca T. , Masotti M. T. , La Mura E. , Vittoria A.
Published: March 2005

The presence of CCK-containing neuroendocrine cells in human adenomatous prostates, and the colocalization of CCK together with serotonin in the same cell, have been demonstrated by means of an immunohistochemical technique and by a double labeling immunofluorescent staining. CCK-containing neuroendocrine cells had a focal distribution in the prostates and sometimes showed dendrite-like cytoplasmic processes. The major part of CCK (96.55%) colocalized with serotonin.

CCK probably stimulates muscle contraction and endocrine/exocrine secretions in the urogenital tract.
Consideration of Genetic Counseling as a Career: Implications for Diversifying the Genetic Counseling Field
Authors: Oh Tracey , Lewis Linwood J.
Published: March 2005

Under‐representation of racial/ethnic minority counselors has been an ongoing issue in the genetic counseling field. A better understanding of genetic counseling awareness and career consideration may help to increase the number of applicants to genetic counseling training programs from racial/ethnic minorities. This study sampled high school and college students (n = 233) to examine their awareness and perceptions of genetic counseling. Ethnicity, gender, parental level of education, and interest in biology were significant predictors of a subject's genetic counseling awareness; previous awareness of genetic counseling, interest in psychology, and level of education were significant predictors of whether a subject would consider genetic counseling as a career. The findings suggest that knowledge of genetic counseling is lower among racial/ethnic minorities, but that racial/ethnic minorities are just as likely to consider genetic counseling as a career. Awareness of genetic counseling prior to university education may increase racial/ethnic minority representation among potential applicants to genetic counseling training programs.
Modelling transport of amino acids into the red blood cells of sheep
Authors: HOLTROP G. , LAPIERRE H. , LOBLEY G. E.
Published: March 2005

Mathematical models have been developed that describe possible sources of the free amino acids (AA) present in the red blood cells (RBC). These models reflect three hypotheses, namely (i) direct transport between plasma and RBC, (ii) enhanced direct transport by deformation of the RBC during passage through capillaries and (iii) direct exchange between tissues and RBC. The latter implies that RBC samples from appropriate blood vessels might offer an alternative to tissue biopsies in protein turnover studies.

These compartmental models were tested against data from ovine studies. For hypothesis (i), a single dose of [U-13C] AA was added to blood in vitro. The rate of disappearance of label from plasma was low (kP=0·0009–0·004 per min), indicative of slow direct transport between plasma and RBC. For hypotheses (ii) and (iii), a single dose of [1-13C] AA was administered intravenously to sheep. Label disappeared from plasma quicker (kP=0·33–0·53 per min) than in vitro, with the appearance of labelled AA in the RBC higher than could be explained from direct transport alone. The model reflecting enhanced exchange of free AA between plasma and RBC due to capillary action over-predicted RBC enrichments and pool sizes by up to five-fold. The third hypothesis, namely that AA in the RBC are predominantly derived from exchange with tissues, gave better agreement. This model suggested that at least 0·63 of the AA in the RBC might come from exchange with tissue.

To investigate whether peripheral tissues (skin and muscle) might be involved in such exchange, an additional experiment was conducted in five sheep prepared with arterio-venous catheters across the hindquarters. [1-13C,15N] leucine was continuously infused, with both blood samples and tissue biopsies taken. The ratio of [1-13C] leucine to [1-13C,15N] leucine was 1·8–2·9 fold greater in muscle and skin compared with arterial plasma, indicative of intracellular transamination. If free leucine exchanged directly between tissues and RBC then the ratio should be higher in RBC isolated from venal caval compared with arterial blood. In practice, the ratios from the RBC in aorta and vena cava were similar (P=0·30). These findings suggest that, for leucine, RBC enrichments do not form an alternative to tissue biopsies to estimate the enrichment of the precursor pool in protein turnover studies of the hindquarter. Instead, other tissues must play a more important role in the exchange of AA with the RBC.
What to do about cows? Princely versus British approaches to a South Asian dilemma
Authors: COPLAND IAN
Published: March 2005

For more than a millennium, cow slaughter has been a source of bitter contention in South Asia. Hindus revere the animal; Muslims like to eat it and, until recently, the cow has been the preferred animal of sacrifice at the Islamic festival of ‘Id-ul-Adha¯. This paper looks at how, over the twentieth century, Indian governments of differing type and ideological colour—British and princely during the late colonial period and Congress nationalist after 1947—have tried to mediate this vexed question. It finds that while policies differed widely, there was a tendency for all governments in the early twentieth century to be guided by social custom and local opinion, so that in the small Muslim-ruled state of Mangrol, which had an official ban, the Muslims who killed cows occasionally for food were never prosecuted so long as they kept their activities discreet—but this ‘discretionary’ option became politically unviable once the country embraced democracy.
White space in northern light: two churches analysed
Authors: Walker David
Published: March 2005

The essence of the art of architecture is the medium of the enclosure of space at a scale that embraces the body as well as the eye. The medium has its greatest potential when it is revealed in daylight because it is the strongest, purest and most subtle of lights. This medium is the product of the synthesis of skills that are often held to be discrete, the ability to manipulate surface and the ability to manipulate volume. Across civilization the conjunction of these skills has been rare; moreover because architecture is a complicated applied art, it is only in the church and temple where the medium can be unfettered and attain great spirituality.
Space to look at things
Authors: Rattray Charles
Published: March 2005

I have a first English edition of Rasmussen's Experiencing Architecture and impressed in the flyleaf is ‘Library of Alan Reiach’.

Ahh! It was a great disappointment to me that Alan's library was split up and didn't come back to the practice.
Glaciological and climatic significance of Hercules Dome, Antarctica: An optimal site for deep ice core drilling
Authors: Jacobel Robert W. , Welch Brian C. , Steig Eric J. , Schneider David P.
Published: March 2005

We present glaciological and climatological characteristics of Hercules Dome, Antarctica (86°S, 105°W), which demonstrate its potential as a deep ice core site. Annual layering in δD ratios from a 72 m ice core collected by the US‐ITASE 2002 traverse indicate accumulation rates of 0.16–0.20 m/yr ice equivalent over the last 300 years. Age control from stratigraphy seen in the radio‐echo sounding data collected during the same traverse suggests a rate of 0.09–0.11 m/yr averaged over the past 18,000 years. Ice stratigraphy also indicates that the ice divide position has been stable through at least this period. Comparison of satellite‐derived temperature anomalies with atmospheric reanalysis data show that the site is sensitive to the two dominant patterns of climate variability in the high‐latitude Southern Hemisphere. Climate proxy data from a deep ice core at Hercules Dome would be indicative of changes in Pacific Southern Hemisphere climate variability and may provide new information on rapid climate change events in Antarctica. The sensitivity of the site and the combination of relatively high accumulation rates, low temperatures (mean annual −35°C to −40°C), and simple ice flow suggest that Hercules Dome is an ideal site for a future deep ice core.
Structure determination of small vanadium clusters by density-functional theory in comparison with experimental far-infrared spectra
Authors: Ratsch C. , Fielicke A. , Kirilyuk A. , Behler J. , von Helden G. , Meijer G. , Scheffler M.
Published: March 2005

The far-infrared vibrational spectra for charged vanadium clusters with sizes of 3–15 atoms have been measured using infrared multiple photon dissociation of Vn+Ar→Vn++Ar. Using density-functional theory calculations, we calculated the ground state energy and vibrational spectra for a large number of stable and metastable geometries of such clusters. Comparison of the calculated vibrational spectra with those obtained in the experiment allows us to deduce the cluster size specific atomic structures. In several cases, a unique atomic structure can be identified, while in other cases our calculations suggest the presence of multiple isomers.
Constructing and exploring wells of energy landscapes
Authors: Aubin Jean-Pierre , Lesne Annick
Published: March 2005

Landscape paradigm is ubiquitous in physics and other natural sciences, but it has to be supplemented with both quantitative and qualitatively meaningful tools for analyzing the topography of a given landscape. We here consider dynamic explorations of the relief and introduce as basic topographic features “wells of duration T and altitude y.” We determine an intrinsic exploration mechanism governing the evolutions from an initial state in the well up to its rim in a prescribed time, whose finite-difference approximations on finite grids yield a constructive algorithm for determining the wells. Our main results are thus (i) a quantitative characterization of landscape topography rooted in a dynamic exploration of the landscape, (ii) an alternative to stochastic gradient dynamics for performing such an exploration, (iii) a constructive access to the wells, and (iv) the determination of some bare dynamic features inherent to the landscape. The mathematical tools used here are not familiar in physics: They come from set-valued analysis (differential calculus of set-valued maps and differential inclusions) and viability theory (capture basins of targets under evolutionary systems) that have been developed during the last two decades; we therefore propose a minimal Appendix exposing them at the end of this paper to bridge the possible gap.
Comparative Advantage in Land-Use Allocation under Regionalism
Authors: Hanink Dean M , Cromley Robert G
Published: March 2005

The Ricardian principle of comparative advantage is used frequently as a foundation for illustrating potential improvements in the allocation of production and trade flows among countries. Such improvements typically consist of increased economic efficiency in the form of lower aggregate production costs and greater welfare in the form of higher levels of aggregate output. The improvements are made possible by the effective integration of otherwise individual economies. This paper employs the principle of comparative advantage as the foundation for illustrating potential improvements in the allocation of land uses under a regional approach to land-use planning. It uses a generalized assignment problem within a geographical information system (GIS) to describe the efficiency benefits of integrating land-use plans among several districts.
The assessment of TGGE for the detection of interspecific and intergeneric DNA-marker polymorphism within Solanaceae
Authors: Garland S. H.
Published: March 2005

RFLP markers are currently the most appropriate marker system for the identification of uncharacterised polymorphism at the interspecific and intergeneric level. Given the benefits of a PCR-based marker system and the availability of sequence information for many Solanaceous cDNA clones, it is now possible to target conserved fragments, for primer development, that flank sequences possessing interspecific polymorphism. The potential outcome is the development of a suite of markers that amplify widely in Solanaceae. Temperature gradient gel electrophoresis (TGGE) is a relatively inexpensive gel-based system that is suitable for the detection of most single-base changes. TGGE can be used to screen for both known and unknown polymorphisms, and has been assessed here, for the development of PCR-based markers that are useful for the detection of interspecific variation within Solanaceae. Fifteen markers are presented where differences between Lycopersicon esculentum and L. pennellii have been detected by TGGE. The markers were assessed on a wider selection of plant species and found to be potentially useful for the identification of interspecific and intergeneric polymorphism in Solanaceous plants.
Additional protein intake limits weight regain after weight loss in humans
Authors: Lejeune Manuela P. G. M. , Kovacs Eva M. R. , Westerterp-Plantenga Margriet S.
Published: March 2005

Since long-term weight maintenance (WM) is a major problem, interventions to improve WM are needed. The aim of the study was to investigate whether the addition of protein to the diet might limit weight regain after a weight loss of 5–10 % in overweight subjects. In a randomised parallel study design, 113 overweight subjects (BMI 29·3 (SD 2·5) kg/m2); age 45·1 (SD 10·4) years) followed a very-low-energy diet for 4 weeks, after which there was a 6-month period of WM. During WM, subjects were randomised into either a protein group or a control group. The protein group received 30 g/d protein in addition to their own usual diet. During the very-low-energy diet, no differences were observed between the groups. During WM, the protein group showed a higher protein intake (18 %v.15 %;P<0·05), a lower weight regain (0·8v.3·0 kg;P<0·05), a decreased waist circumference (−1·2 (SD 0·7)v.0·5 (SD 0·5 ) cm;P<0·05) and a smaller increase in respiratory quotient (0·03 (SD 0·01)v.0·07 0·01; (SD/)P<0·05) compared with the control group. Weight regain in the protein group consisted of only fat-free mass, whereas the control group gained fat mass as well. Satiety in the fasted state before breakfast increased significantly more in the protein group than in the control group. After 6 months follow-up, body weight showed a significant group × time interaction. A protein intake of 18 % compared with 15 % resulted in improved WM in overweight subjects after a weight loss of 7·5 %. This improved WM implied several factors, i.e. improved body composition, fat distribution, substrate oxidation and satiety.
Glycoprotein gp130 ofDictyostelium discoideumInfluences Macropinocytosis and Adhesion
Authors: Chia Catherine P. , Gomathinayagam Sujatha , Schmaltz Robert J. , Smoyer Laura K.
Published: March 2005

Glycoprotein gp130, found on the plasma membrane of Dictyostelium discoideum amoebae, was postulated previously to play a role in phagocytosis. The gene for gp130 was cloned and when translated, yielded a 768 amino acid preproprotein of 85.3 kDa. It had nearly 40% similarity to the 138 kDa family of glycoproteins implicated in sexual cell fusion during macrocyst formation in D. discoideum. The difference between the calculated size and observed Mrof 130 kDa on protein gels likely was due to N-glycosylation that was confirmed by lectin blots. Consistent with its surface-exposure, an antibody raised against recombinant protein stained the plasma membrane of D. discoideum amoebae. Gp130 and its transcripts were high during axenic growth of cells, but relatively low during growth on bacteria. The gene for gp130 was disrupted and cell lines lacking the glycoprotein were efficient phagocytes, indicating that gp130 was dispensable for phagocytosis. Gp130-null cells were similar in size to parent DH1 cells, had enhanced macropinocytosis and grew faster to higher densities. They also exhibited weaker cell-substrate adhesion but displayed greater cell-cell cohesion. Collectively, the data indicated that gp130 influenced macropinocytosis and played a role in adhesion during vegetative growth.
Structural and Functional Characterization of Noncoding Repetitive RNAs Transcribed in Stressed Human Cells
Authors: Valgardsdottir Rut , Chiodi Ilaria , Giordano Manuela , Cobianchi Fabio , Riva Silvano , Biamonti Giuseppe
Published: March 2005

Thermal and chemical stresses induce the formation in human cells of novel and transient nuclear structures called nuclear stress bodies (nSBs). These contain heat shock factor 1 (HSF-1) and a specific subset of pre-mRNA processing factors. Nuclear stress bodies are assembled on specific pericentromeric heterochromatic domains containing satellite III (SatIII) DNA. In response to stress, these domains change their epigenetic status from heterochromatin to euchromatin and are transcribed in poly-adenylated RNAs that remain associated with nSBs. In this article, we describe the cloning, sequencing, and functional characterization of these transcripts. They are composed of SatIII repeats and originate from the transcription of multiple sites within the SatIII arrays. Interestingly, the level of SatIII RNAs can be down-regulated both by antisense oligonucleotides and small interfering RNAs (siRNA). Knockdown of SatIII RNA by siRNAs requires the activity of Argonaute 2, a component of the RNA-induced silencing complex. Down-regulation of satellite III RNAs significantly affects the recruitment of RNA processing factors to nSBs without altering the association of HSF-1 with these structures nor the presence of acetylated histones within nSBs. Thus, satellite III RNAs have a major role in the formation of nSBs.
CURRENT DEVELOPMENTS: I. COMMUNITY COURTS IN THE AREA OF JUDICIAL COOPERATION
Authors: Nascmbene Bruno
Published: March 2005

A. The area of freedom, security and justice and the role of the Court of Justice

One of the subjects which has aroused particular interest in the study of the ‘area of freedom, security and justice’ introduced by the Treaty of Amsterdam as an objective of the European Union (EU) inherent in the principle of the free movement of persons (see the preamble to, and Article 2, the Treaty on EU) is the role of the European Court of Justice (Court). The interest is both theoretical and practical, because one of the main issues is the Court's jurisdiction to give preliminary rulings and thus relations between national and Community courts and the protection of the interests of individuals before national courts wherever there is a conflict between national and Community law and thus a question of interpretation of Community law arises in national proceedings. The Treaty of Nice, which came into force on 1 February 2003, altered the jurisdiction and organisation of the Community judicature and therefore affected the ‘area of freedom, security and justice’.1
Partial Validation of the Dutch Model for Emission and Transport of Nutrients (STONE)
Authors: Overbeek G.B.J. , Tiktak A. , Beusen A.H.W. , van Puijenbroek P.J.T.M.
Published: March 2005

The Netherlands has to cope with large losses of N and P to groundwater and surface water. Agriculture is the dominant source of these nutrients, particularly with reference to nutrient excretion due to intensive animal husbandry in combination with fertilizer use. The Dutch government has recently launched a stricter eutrophication abatement policy to comply with the EC nitrate directive. The Dutch consensus model for N and P emission to groundwater and surface water (STONE) has been developed to evaluate the environmental benefits of abatement plans. Due to the possibly severe socioeconomic consequences of eutrophication abatement plans, it is of utmost importance that the model is thoroughly validated. Because STONE is applied on a nationwide scale, the model validation has also been carried out on this scale. For this purpose the model outputs were compared with lumped results from monitoring networks in the upper groundwater and in surface waters. About 13,000 recent point source observations of nitrate in the upper groundwater were available, along with several hundreds of observations showing N and P in local surface water systems. Comparison of observations from the different spatial scales available showed the issue of scale to be important. Scale issues will be addressed in the next stages of the validation study.
Nitrogen Loss Estimation Worksheet (NLEW): An Agricultural Nitrogen Loading Reduction Tracking Tool
Authors: Osmond Deanna L. , Xu Lin , Ranells Noah N. , Hodges Steve C. , Hansard Roger , Pratt Stephen H.
Published: March 2005

The Neuse River Basin in North Carolina was regulated in 1998, requiring that all pollution sources (point and nonpoint) reduce nitrogen (N) loading into the Neuse Estuary by 30%. Point source N reductions have already been reduced by approximately 35%. The diffuse nature of nonpoint source pollution, and its spatial and temporal variability, makes it a more difficult problem to treat. Agriculture is believed to contribute over 50% of the total N load to the river. In order to reduce these N inputs, best management practices (BMPs) are necessary to control the delivery of N from agricultural activities to water resources and to prevent impacts to the physical and biological integrity of surface and ground water. To provide greater flexibility to the agricultural community beyond standard BMPs (nutrient management, riparian buffers, and water-control structures), an agricultural N accounting tool, called Nitrogen Loss Estimation Worksheet (NLEW), was developed to track N reductions due to BMP implementation. NLEW uses a modified N-balance equation that accounts for some N inputs as well as N reductions from nutrient management and other BMPs. It works at both the field- and county-level scales. The tool has been used by counties to determine different N reduction strategies to achieve the 30% targeted reduction.
Estimated Historical and Current Nitrogen Balances for Illinois
Authors: David Mark B. , McIsaac Gregory F. , Royer Todd V. , Darmody Robert G. , Gentry Lowell E.
Published: March 2005

The Midwest has large riverine exports of nitrogen (N), with the largest flux per unit area to the Mississippi River system coming from Iowa and Illinois. We used historic and current data to estimate N inputs, outputs, and transformations for Illinois where human activity (principally agriculture and associated landscape drainage) have had a dominant impact. Presently, ~800,000 Mg of N is added each year as fertilizer and another 420,000 Mg is biologically fixed, primarily by soybean (Glycine max L. Merr.). These annual inputs are greater than exports in grain, which results in surplus N throughout the landscape. Rivers within the state export approximately 50% of this surplus N, mostly as nitrate, and the remainder appears to be denitrified or temporarily incorporated into the soil organic matter pool. The magnitude of N losses for 1880, 1910, 1950, and 1990 are compared. Initial cultivation of the prairies released large quantities of N (~500,000 Mg N year�1), and resulted in riverine N transport during the late 19th century that appears to have been on the same order of magnitude as contemporary N losses. Riverine flux was estimated to have been at a minimum in about 1950, due to diminished net mineralization and low fertilizer inputs. Residual fertilizer N from corn (Zea mays L.), biological N fixed by soybean, short-circuiting of soil water through artificial drainage, and decreased cropping-system diversity appear to be the primary sources for current N export.
Factors Affecting Microbial Formation of Nitrate-Nitrogen in Soil and Their Effects on Fertilizer Nitrogen Use Efficiency
Authors: Olness Alan , Lopez Dian , Archer David , Cordes Jason , Sweeney Colin , Mattson Neil , Rinke Jana , Voorhees W. B.
Published: March 2005

Mineralization of soil organic matter is governed by predictable factors with nitrate-N as the end product. Crop production interrupts the natural balance, accelerates mineralization of N, and elevates levels of nitrate-N in soil. Six factors determine nitrate-N levels in soils: soil clay content, bulk density, organic matter content, pH, temperature, and rainfall. Maximal rates of N mineralization require an optimal level of air-filled pore space. Optimal air-filled pore space depends on soil clay content, soil organic matter content, soil bulk density, and rainfall. Pore space is partitioned into water- and air-filled space. A maximal rate of nitrate formation occurs at a pH of 6.7 and rather modest mineralization rates occur at pH 5.0 and 8.0. Predictions of the soil nitrate-N concentrations with a relative precision of 1 to 4 μg N g–1of soil were obtained with a computerized N fertilizer decision aid. Grain yields obtained using the N fertilizer decision aid were not measurably different from those using adjacent farmer practices, but N fertilizer use was reduced by >10%. Predicting mineralization in this manner allows optimal N applications to be determined for site-specific soil and weather conditions.
Prediction of Nitrogen Responses of Corn by Soil Nitrogen Mineralization Indicators
Authors: Simard R.R. , Ziadi N. , Nolin M.C. , Cambouris A.N.
Published: March 2005

Soil nitrogen mineralization potential (Nmin) has to be spatially quantified to enable farmers to vary N fertilizer rates, optimize crop yields, and minimize N transfer from soils to the environment. The study objectives were to assess the spatial variability in soil Nminpotential based on clay and organic matter (OM) contents and the impact of grouping soils using these criteria on corn grain (Zea mays L.) yield, N uptake response curves to N fertilizer, and soil residual N. Four indicators were used: OM content and three equations involving OM and clay content. The study was conducted on a 15-ha field near Montreal, Quebec, Canada. In the spring 2000, soil samples (n = 150) were collected on a 30- x 30-m grid and six rates of N fertilizer (0 to 250 kg N ha-1) were applied. Kriged maps of particle size showed areas of clay, clay loam, and fine sandy loam soils. The Nminindicators were spatially structured but soil nitrate (NO3–) was not. The N fertilizer rate to reach maximum grain yield (Nmax), as estimated by a quadratic model, varied among textural classes and Nminindicators, and ranged from 159 to 250 kg N ha-1. The proportion of variability (R2) and the standard error of the estimate (SE) varied among textural groups and Nminindicators. The R2ranged from 0.53 to 0.91 and the SE from 0.13 to 1.62. Corn grain N uptake was significantly affected by N fertilizer and the pattern of response differed with soil texture. For the 50 kg N ha-1rate, the apparent Nminpotential (ANM) was significantly larger in the clay loam (122 kg ha-1) than in the fine sandy loam (80 kg ha-1) or clay (64 kg ha-1) soils. The fall soil residual N was not affected by N fertlizer inputs. Textural classes can be used to predict Nmax. The Nminindicators may also assist the variable rate N fertilizer inputs for corn production.
Merging Nitrogen Management and Renewable Energy Needs
Authors: Wilson Elizabeth , Chapman Pippa J. , McDonald Adrian
Published: March 2005

The ARBRE (ARable Biomass Renewable Energy) project, the first large-scale wood-fueled electricity generating plant in the U.K., represents a significant development in realising British and European policy objectives on renewable energy. The plant is fueled by a mix of wood from short rotation coppice (SRC) and forest residues. Where feasible, composted/conditioned sewage sludge is applied to coppice sites to increase yields and improve soil structure. In the Yorkshire Water region, typical total N:P:K composition of composted/conditioned sludge is 2.9:3.8:0.3, respectively. Sludge application is calculated on the basis of total nitrogen (N) content to achieve 750 kg N ha-1, for 3 years’ requirement. Willow coppice forms a dense, widely spaced, root network, which, with its long growing season, makes it an effective user of nutrients. This, in combination with willow’s use as a nonfood, nonfodder crop, makes it an attractive route for the recycling of sewage sludge in the absence of sea disposal, banned under the EC Urban Waste Water Treatment Directive (UWWTD). Further work is required on the nutritional requirements of SRC in order to understand better the quantities of sludge that can be applied to SRC without having a detrimental impact on the environment. This paper suggests the source of N rerouting under the UWWTD and suggests the likely expansion of SRC as an alternative recycling pathway.
Habitat Management: A Tool to Modify Ecosystem Impacts of Nitrogen Deposition?
Authors: Power S.A. , Barker C.G. , Allchin E.A. , Ashmore M.R. , Bell J.N.B.
Published: March 2005

Atmospheric nitrogen deposition has been shown to affect both the structure and the function of heathland ecosystems. Heathlands are semi-natural habitats and, as such, undergo regular management by mowing or burning. Different forms of management remove more or less nutrients from the system, so habitat management has the potential to mitigate some of the effects of atmospheric deposition. Data from a dynamic vegetation model and two field experiments are presented. The first involves nitrogen addition following different forms of habitat management. The second tests the use of habitat management to promote heathland recovery after a reduction in nitrogen deposition. Both modelling and experimental approaches suggest that plant and microbial response to nitrogen is affected by management. Shoot growth and rates of decomposition were lowest in plots managed using more intensive techniques, including mowing with litter removal and a high temperature burn. Field data also indicate that ecosystem recovery from prolonged elevated inputs of nitrogen may take many years, or even decades, even after the removal of plant and litter nitrogen stores which accompanies the more intensive forms of habitat management.
Concentrations, Deposition, and Effects of Nitrogenous Pollutants in Selected California Ecosystems
Authors: Bytnerowicz Andrzej , Padgett Pamela E. , Parry Sally D. , Fenn Mark E. , Arbaugh Michael J.
Published: March 2005

Atmospheric deposition of nitrogen (N) in California ecosystems is ecologically significant and highly variable, ranging from about 1 to 45 kg/ha/year. The lowest ambient concentrations and deposition values are found in the eastern and northern parts of the Sierra Nevada Mountains and the highest in parts of the San Bernardino and San Gabriel Mountains that are most exposed to the Los Angeles air pollution plume. In the Sierra Nevada Mountains, N is deposited mostly in precipitation, although dry deposition may also provide substantial amounts of N. On the western slopes of the Sierra Nevada, the majority of airborne N is in reduced forms as ammonia (NH3) and particulate ammonium (NH4+) from agricultural activities in the California Central Valley. In southern California, most of the N air pollution is in oxidized forms as nitrogen oxides (NOx), nitric acid (HNO3), and particulate nitrate (NO3–) resulting from fossil fuel combustion and subsequent complex photochemical reactions. In southern California, dry deposition of gases and particles provides most (up to 95%) of the atmospheric N to forests and other ecosystems. In the mixed-conifer forest zone, elevated deposition of N may initially benefit growth of vegetation, but chronic effects may be expressed as deterioration of forest health and sustainability. HNO3vapor alone has a potential for toxic effects causing damage of foliar surfaces of pines and oaks. In addition, dry deposition of predominantly HNO3has lead to changes in vegetation composition and contamination of ground- and stream water where terrestrial N loading is high. Long-term, complex interactions between N deposition and other environmental stresses such as elevated ozone (O3), drought, insect infestations, fire suppression, or intensive land management practices may affect water quality and sustainability of California forests and other ecosystems.
Don’t-Ask-Don’t-Tell Policy Strangles Research and Do-Gooder Intentions Ablaze
Authors: Haley Shauna M.
Published: March 2005

Nature starts the news week by chronicling epidemiological researchers’ wrath over how Britain’s General Medical Council (GMC) has implemented the nation’s 1998 Data Protection Act. Science fires up its news with coverage of the torching of two plant labs in the northwestern U.S. by ecoterrorists.
Assessment of Heart Disease using Fuzzy Classification Techniques
Authors: Pop Horia F. , Pop Tudor L. , Sarbu Costel
Published: March 2005

In this paper we discuss the classification results of cardiac patients of ischemical cardiopathy, valvular heart disease, and arterial hypertension, based on 19 characteristics (descriptors) including ECHO data, effort testings, and age and weight. In this order we have used different fuzzy clustering algorithms, namely hierarchical fuzzy clustering, hierarchical and horizontal fuzzy characteristics clustering, and a new clustering technique, fuzzy hierarchical cross-classification. The characteristics clustering techniques produce fuzzy partitions of the characteristics involved and, thus, are useful tools for studying the similarities between different characteristics and for essential characteristics selection. The cross-classification algorithm produces not only a fuzzy partition of the cardiac patients analyzed, but also a fuzzy partition of their considered characteristics. In this way it is possible to identify which characteristics are responsible for the similarities or dissimilarities observed between different groups of patients.
ChemBank Coming Soon and the Latest Great Flood Claims Research
Authors: Haley Shauna
Published: March 2005

Nature leads the news week with a report on a new database initiative designed to catalog the effects of small molecules on proteins. Tropical Storm Allison’s widespread destruction of research at Texas universities tops the news in Science.
Introduction to Maxxam All-Season Passive Sampling System and Principles of Proper Use of Passive Samplers in the Field Study
Authors: Tang Hongmao
Published: March 2005

Maxxam all-season passive sampling system (PASS) is introduced in this paper. The PASS can be used to quantitatively and accurately monitor SO2, NO2, O3, and H2S in air in all weather conditions with flexible exposure times from several hours to several months. The air pollution detection limits of PASS are very low. They can be from sub ppb to ppt levels. The principles of proper use of passive samplers in the field study are discussed by using the PASS as an example.
Experimental and Theoretical Study of the Enthalpy of Formation of 3,6-Diphenyl-1,2,4,5-Tetroxane Molecule
Authors: Jorge N.L. , Leiva L.C.A. , Castellanos M.G. , Vara M.E. Gomez , Cafferata L.F.R. , Castro E.A.
Published: March 2005

We report the results obtained for the experimental determination and the theoretical calculation of the enthalpy of formation of 3,6-diphenyl-1,2,4,5-tetroxane molecule. The experimental work was performed using a macrocalorimeter to measure the combustion heat, and the sublimation enthalpy was determined via the measurement of the vapor pressure at equilibrium with the vapor phase at different temperatures resorting to the Clapeyron-Claussius equation. Theoretical calculations were performed using semiempirical AM1 and PM3 methods as well asab initiotechniques at the 3-21, 6-31G(d,p), and 6-311G(d,p) basis set levels.
Hydroxyurea Treatment for Sickle Cell Disease
Authors: Steinberg Martin H.
Published: March 2005

High fetal hemoglobin (HbF) levels inhibit the polymerization of sickle hemoglobin (HbS) and reduce the complications of sickle cell disease. Pharmacologic agents that can reverse the switch from γ- to β-chain synthesis — γ-globin chains characterize HbF, and sickle β-globin chains are present in HbS — or selectively increase the proportion of adult erythroid precursors that maintain the ability to produce HbF are therapeutically useful. Hydroxyurea promotes HbF production by perturbing the maturation of erythroid precursors. This treatment increases the total hemoglobin concentration, reduces the vaso-occlusive complications of pain and acute chest syndrome, and attenuates mortality in adults. It is a promising beginning for pharmacologic therapy of sickle cell disease. Still, its effects are inconsistent, trials in infants and children are ongoing, and its ultimate value — and peril — when started early in life are still unknown.
Atmospheric Deposition of Phosphorus to the Everglades: Concepts, Constraints, and Published Deposition Rates for Ecosystem Management
Authors: Redfield Garth W.
Published: March 2005

This paper summarizes concepts underlying the atmospheric input of phosphorus (P) to ecosystems, published rates of P deposition, measurement methods, and approaches to future monitoring and research. P conveyed through the atmosphere can be a significant nutrient source for some freshwater and marine ecosystems. Particle sources and sinks at the land-air interface produce variation in P deposition from the atmosphere across temporal and spatial scales. Natural plant canopies can affect deposition rates by changing the physical environment and surface area for particle deposition. Land-use patterns can alter P deposition rates by changing particle concentrations in the atmosphere. The vast majority of P in dry atmospheric deposition is conveyed by coarse (2.5 to 10 μm) and giant (10 to 100 μm) particles, and yet these size fractions represent a challenge for long-term atmospheric monitoring in the absence of accepted methods for routine sampling. Most information on P deposition is from bulk precipitation collectors and wet/dry bucket sampling, both with questionable precision and accuracy. Most published annual rates of P deposition are gross estimates derived from bulk precipitation sampling in locations around the globe and range from about 5 to well over 100 mg P m–2year–1, although most inland ecosystems receive between 20 and 80 mg P m–2year–1. Rates below 30 mg P m–2year–1are found in remote areas and near coastlines. Intermediate rates of 30 to 50 mg P m–2year–1are associated with forests or mixed land use, and rates of 50 to 100 mg P m–2year–1or more are often recorded from urban or agricultural settings. Comparison with other methods suggests that these bulk precipitation estimates provide crude boundaries around actual P deposition rates for various land uses. However, data screening cannot remove all positive bias caused by contamination of bucket or bulk collectors. As a consequence, continued sampling with these standard collectors in a region will not reduce the large uncertainty in rates derived from existing data. Calibrated surface accumulation methods hold promise as a primary means to estimate P flux in future monitoring. New methods for long-term P deposition monitoring will require an intercomparison of P flux estimates from surrogate surfaces, impactor sampling of particle concentrations combined with deposition models, and “throughfall” estimates for natural canopies. With better sampling methods and more long-term monitoring data, the importance of atmospheric P deposition in ecosystem dynamics and management can be better understood and predicted.
Separation of Human Monocytes from a Leukocyte-Rich Plasma
Authors: Graham John
Published: March 2005

Human peripheral blood monocytes are isolated by flotation from a dense leukocyte-rich plasma (LRP) through two lower-density barriers prepared from OptiPrep™. The separation from lymphocytes depends on the more rapid rate of flotation of the monocytes because of their slightly lower density and larger size. The method works optimally only with fresh (within 2 h of drawing) EDTA-anticoagulated blood.
A Case Report of Possible Health Benefits of Extra Virgin Olive Oil
Authors: Shahtahmasebi Said , Shahtahmasebi Shahnaz
Published: March 2005

The literature on the chemical analysis of cooking oils suggests that the cholesterol-reducing effect may well be due to the antioxidant agents rather than unsaturated fats. Furthermore, antioxidant agents are present in extra virgin olive oil and not in olive oil. There is some evidence, based on studies using patients, to support such a supposition. In this paper, we present a case report on the possible health effects of changing from olive oil to extra virgin olive oil. The case report is intended to raise some relevant issues to stimulate a debate and more research in this area.
Lack of Male-Female Differences in Disposition and Esterase Hydrolysis of Ramipril to Ramiprilat in Healthy Volunteers after a Single Oral Dose
Authors: Vree Tom B. , Dammers Erik , Ulc Ivan , Horkovics-Kovats Stefan , Ryska Miroslav , Merkx IJsbrand
Published: March 2005

The objective of this study was to identify differences in disposition and esterase hydrolysis of ramipril between male and female volunteers. Plasma concentration and area under the concentration-time curve until the last measured concentration (AUCt) data of ramipril and its active metabolite ramiprilat (-diacid) were obtained from a randomised, cross-over bioequivalence study in 36 subjects (18 females and 18 males). Participants received a single 5-mg oral dose of two different formulations of ramipril (Formulation I and II). Plasma ramipril and ramiprilat concentrations were determined according to validated methods involving liquid chromatography-mass spectrometry. A total number of 2 � 34 available plasma concentration-time curves of both the parent drug and the metabolite could be analysed, and variations (50�100% coefficient of variation [CV]) in plasma concentrations of both parent drug and metabolite were found. With both the formulations, the mean plasma concentrations-time curves of males and females were identical. The groups of female and male volunteers showed similar yields (AUCt = mg.h/L) of the metabolite ramiprilat (p = 0.37); however, females showed a higher AUCt/kg than males (p = 0.046). This difference was solely attributed to the difference in body weight between males and females (p = 0.00049). In both male and female groups, a subject-dependent yield of active metabolite ramiprilat was demonstrated, which was independent of the formulation.There is a large variation in the ramiprilat t1/2β(50�60% CV). There is a group of subjects who showed a t1/2βof approximately 80 h (15% CV), and two apparent groups with a longer t1/2βfor each formulation (124 h, 22.5% CV; 166 h, 21.6% CV, respectively, p = 0.0013). This variation in the terminal half-life of ramiprilat is not sex related. In all three groups of half-lives, the corresponding Cmax values (mean � SD) of ramiprilat in males and females were identical. Thus, with identical Cmaxand half-lives, the difference found in the AUCt/kg of ramiprilat must be due to the difference in dose, as the consequence of the difference in body weight, following a standard dose of 5 mg in both males and females.This study showed clearly that despite subject-dependent hydrolysis of ramipril to the active metabolite ramiprilat, the variability in the rate of hydrolysis between males and females is similar. With a fixed dose (5 mg), females received a higher dose/kg than males and consequently showed a higher AUCt/kg of the active metabolite ramiprilat.