bluuebunny/crossref_metadata_2025 huggingface dataset:
Does physical exercise modify antioxidant requirements?
Authors: Margaritis I. , Rousseau A. S.
Published: July 2008

Physical training is known to induce a biochemical adaptive response which might require an increase in the ingestion and/or the absorption of micronutrients. A question that is still being raised is whether acute or chronic exercise modifies antioxidant requirements. First, the present review brings to light the most crucial studies on the topic. Second, it interprets the established relationships between antioxidant micronutrient intakes and the adaptive response of antioxidant systems. Finally, it exposes the major questions connected with antioxidant micronutrient requirements for athletes. To this effect, the training-load interaction with nutrition is taken into account. As oxidative stress cannot be avoided, the imbalance between oxidants and antioxidants can be alleviated to minimise oxidative damage and outcomes. There is growing evidence that one specific antioxidant cannot by itself prevent oxidative stress-induced damage, as direct adverse effects of supplementation are attributed to undesirable synergic effects. Other effects can be supposed that limit the endogenous adaptive effect of training. High doses of antioxidant supplements can minimise the effects of radical oxygen species themselves or generate pro-oxidant effects. Effects are only exhibited when nutritional status is deficient. There are no convincing effects of supplementation in well-trained athletes. Risk/benefit analysis emerges on evidence for an unknown risk of supranutritional intakes, a supposed impairment of adaptive effects and a still unknown long-term risk. Appropriate status can be achieved by a diversified and balanced diet, adapted to specific needs, by awareness of high-density food intakes (avoiding products containing a low density of micronutrients).
Recent developments in English intensifiers: the case ofvery much
Authors: GONZÁLEZ-DÍAZ VICTORINA
Published: July 2008

The nature and behaviour of complex and compound adverbs (e.g.very much,heretofore,anyway) has not received much scholarly attention in recent years. In the case ofvery much, for instance, recent literature (e.g. Dixon 2005) considers it a clause-internal adverb which typically modifies phrasal constituents (e.g.I liked the present very much;very much alive). The latter claim, however, appears to clash with previous observations (cf. Bolinger 1972) on the growing scope of the adverb in Present-day English. Through a corpus-based diachronic study (1500–present day), the present article unearths a number of environments wherevery muchdoes not seem to fit neatly within the functional classifications that it has been assigned to in recent literature and standard grammars of English. It suggests that, from the Late Modern English period onwards (1800–),very muchseems to have been developing sentence modifier functions, hence moving along Traugott's (1995)Internal Adverb > Sentence Adverb > Discourse Particlecline.
Social variation in intensifier use: constraint on-lyadverbialization in the past?
Authors: NEVALAINEN TERTTU
Published: July 2008

While the formation of deadjectival adjuncts by means of -lysuffixation is regular in the mainstream varieties of English today (they singAdj-ly), that of intensifying word modifiers is much less so (they singAdj-ly/Øwell). Both categories are typically more variable in many social and regional varieties, in which zero-form adverbs dominate. This article studies the extent to which grammatical and social conditioning played a role in the choice of the form of deadjectival intensifiers between the fifteenth and seventeenth centuries, before the era of normative grammar. The results indicate that some of the trends of social embedding identified in Present-day English can indeed be observed in the past, but also that the -lysuffix was clearly less grammaticalized four hundred years ago than it is today.
Configurations, construals and change: expressions of DEGREE
Authors: PARADIS CARITA
Published: July 2008

This article challenges the widespread view thatdegreeis a grammatical phenomenon characteristic of certain types of word classes and, instead, argues thatdegreeis pervasive in language and may be associated with most meanings. The main aim of the article is to discuss the results of a number of corpus investigations and experiments ofdegreemeanings in general and of the modification ofdegreein particular, and to accommodate these results in a general and dynamic model of Lexical Meaning as Ontologies and Construals (LOC; Paradis 2005). The claims are that (i)degreeis aboundednessconfiguration in conceptual space; (ii)degreemodifiers operate on thedegreestructure of the meanings to which they apply through a construal of contextually motivated zone activationwithinconventionalized senses; (iii) nonconventionalizeddegreereadings of form–meaning pairings are invoked through implication by means of construals of metonymizationbetweensenses; and (iv) this process of metonymization is the mechanism through which change may or may not take place.
So different and pretty cool! Recycling intensifiers in Toronto, Canada
Authors: TAGLIAMONTE SALI A.
Published: July 2008

This article presents a synchronic quantitative study of the intensifier system in Toronto, the largest urban centre in Canada. The data comprise nearly 10,000 adjectival heads, as inI wassohungry and I was gettingreallynauseous(TOR/2m). The distribution of intensifiers in apparent time provides startling evidence of change.Veryis quickly moving out of favour andreallyhas expanded dramatically. Moreover, there is evidence to suggest that other intensifiers are on the rise –soandpretty. Testing a series of contextual factors known to operate in the development of intensifiers (e.g. adjective function and type) as well as their intersection with social factors (e.g. age and sex) reveals evidence of ongoing delexicalization, but not as part of a continual longitudinal process. Instead, the profile of change reveals recycling, suggesting that the mechanisms of intensifier renewal may be more complex than previously thought.
WHY I AM A SKEPTIC ABOUT RELIGIOUS CLAIMS
Authors: Kurtz Paul
Published: July 2008

Paul Kurtz recommends we subject religious claims to proper critical scrutiny. He believes that when we do, we will discover that skepticism is the only sensible position to adopt.
THINKING TOOLS. Fallacy: TWO WRONGS MAKE A RIGHT
Authors: Law Stephen
Published: July 2008

Thinking tools is a regular feature that offers tips and pointers on thinking clearly and rigorously.
Release of biodegradable dissolved organic matter from ancient sedimentary rocks
Authors: Schillawski Sarah , Petsch Steven
Published: July 2008

Sedimentary rocks contain the largest mass of organic carbon on Earth, yet these reservoirs are not well integrated into modern carbon budgets. Here we describe the release of dissolved organic matter (DOM) from OM‐rich sedimentary rocks under simulated weathering conditions. Results from column experiments demonstrate slow, sustained release of DOM from ancient sedimentary rocks under simulated weathering conditions. 1H‐NMR analysis of shale‐derived DOM reveals a highly aliphatic, carbohydrate‐poor material distinct from other natural DOM pools. Shale‐derived DOM is rapidly assimilated and biodegraded by aerobic heterotrophic bacteria. Consequently, no compositional signature of shale‐derived DOM other than 14C‐depletion is likely to persist in rivers or other surface reservoirs. Combined, these efforts show that dissolution provides a mechanism for the conversion of refractory kerogen into labile biomass, linking rock weathering with sedimentary OM oxidation and the delivery of aged OM to rivers and ocean margins.
Hikurangi Plateau: Crustal structure, rifted formation, and Gondwana subduction history
Authors: Davy Bryan , Hoernle Kaj , Werner Reinhard
Published: July 2008

Seismic reflection profiles across the Hikurangi Plateau Large Igneous Province and adjacent margins reveal the faulted volcanic basement and overlying Mesozoic‐Cenozoic sedimentary units as well as the structure of the paleoconvergent Gondwana margin at the southern plateau limit. The Hikurangi Plateau crust can be traced 50–100 km southward beneath the Chatham Rise where subduction cessation timing and geometry are interpreted to be variable along the margin. A model fit of the Hikurangi Plateau back against the Manihiki Plateau aligns the Manihiki Scarp with the eastern margin of the Rekohu Embayment. Extensional and rotated block faults which formed during the breakup of the combined Manihiki‐Hikurangi plateau are interpreted in seismic sections of the Hikurangi Plateau basement. Guyots and ridge‐like seamounts which are widely scattered across the Hikurangi Plateau are interpreted to have formed at 99–89 Ma immediately following Hikurangi Plateau jamming of the Gondwana convergent margin at ∼100 Ma. Volcanism from this period cannot be separately resolved in the seismic reflection data from basement volcanism; hence seamount formation during Manihiki‐Hikurangi Plateau emplacement and breakup (125–120 Ma) cannot be ruled out. Seismic reflection data and gravity modeling suggest the 20‐Ma‐old Hikurangi Plateau choked the Cretaceous Gondwana convergent margin within 5 Ma of entry. Subsequent uplift of the Chatham Rise and slab detachment has led to the deposition of a Mesozoic sedimentary unit that thins from ∼1 km thickness northward across the plateau. The contrast with the present Hikurangi Plateau subduction beneath North Island, New Zealand, suggests a possible buoyancy cutoff range for LIP subduction consistent with earlier modeling.
Model for Simulating Aerosol Interactions and Chemistry (MOSAIC)
Authors: Zaveri Rahul A. , Easter Richard C. , Fast Jerome D. , Peters Leonard K.
Published: July 2008

This paper describes and evaluates a new Model for Simulating Aerosol Interactions and Chemistry (MOSAIC), with a special focus on addressing the long‐standing issues in solving the dynamic partitioning of semivolatile inorganic gases (HNO3, HCl, and NH3) to size‐distributed atmospheric aerosol particles. The coupled ordinary differential equations (ODE) for dynamic gas‐particle mass transfer are extremely stiff, and the available numerical techniques are either very expensive or produce oscillatory solutions. These limitations are overcome in MOSAIC with a new dynamic gas‐particle partitioning module, which is coupled to an efficient and accurate thermodynamics module. The algorithm includes a new concept of “dynamic pH,” a novel formulation for mass transfer to mixed‐phase and solid particles, and an adaptive time stepping scheme, which together hold the key to smooth, accurate, and efficient solutions of gas‐particle partitioning over the entire relative humidity range. MOSAIC is found to be in excellent agreement with a benchmark version of the model that uses a rigorous solver for integrating the stiff ODEs. The steady‐state MOSAIC results for monodisperse aerosol test cases are also in excellent agreement with those obtained with the benchmark equilibrium model AIM. Moreover, the CPU times required for fully dynamic solutions by MOSAIC per size bin per 5 min intervals (typical 3‐D model time steps) are similar to those for bulk equilibrium solutions by the computationally efficient but relatively less accurate model ISORROPIA. These results show that MOSAIC is extremely efficient without compromising accuracy, and is therefore highly attractive for use in air quality and regional/global aerosol models.
Statistical comparison of properties of simulated and observed cumulus clouds in the vicinity of Houston during the Gulf of Mexico Atmospheric Composition and Climate Study (GoMACCS)
Authors: Jiang Hongli , Feingold Graham , Jonsson Haflidi H. , Lu Miao‐Ling , Chuang Patrick Y. , Flagan Richard C. , Seinfeld John H.
Published: July 2008

We present statistical comparisons of properties of clouds generated by Large Eddy Simulations (LES) with aircraft observations of nonprecipitating, warm cumulus clouds made in the vicinity of Houston, TX during the Gulf of Mexico Atmospheric Composition and Climate Study (GoMACCS), carried out in the summer of 2006. Aircraft data were sampled with the Center for Interdisciplinary Remotely Piloted Aircraft Studies (CIRPAS) Twin Otter airplane. Five flights (days) that are most suitable for studying aerosol‐cloud interactions are selected from the 22 flights. The model simulations are initiated with observed environmental profiles. The simulations are used to generate an ensemble of thousands of cumulus clouds for statistically meaningful evaluations. Statistical comparisons focus on the properties of a set of dynamical and thermodynamical variables, sampled either in the cloud or the cloud updraft core. The set of variables includes cloud liquid water content (LWC), number mixing ratio of cloud droplets (Nd), cloud effective radius (re), updraft velocity (w), and the distribution of cloud sizes. In general, good agreement between the simulated and observed clouds is achieved in the normalized frequency distribution functions, the profiles averaged over the cloudy regions, the cross‐cloud averages, and the cloud size distributions, despite big differences in sample size between the model output and the aircraft data. Some unresolved differences in frequency distributions of w and possible differences in cloud fraction are noted. These comparisons suggest that the LES is able to successfully generate the cumulus cloud populations that were present during GoMACCS. The extent to which this is true will depend on the specific application.
Modeling air temperature through a combination of remote sensing and GIS data
Authors: Cristóbal J. , Ninyerola M. , Pons X.
Published: July 2008

Air temperature is involved in many environmental processes such as actual and potential evapotranspiration, net radiation and species distribution. Ground meteorological stations provide important local data of air temperature, but a continuous surface for large and heterogeneous areas is also needed. In this paper we present a hybrid methodology between Remote Sensing and Geographical Information Systems to retrieve daily instantaneous, mean, maximum and minimum air temperatures (2002–2004) as well as monthly and annual mean, maximum and minimum air temperatures (2000–2005) on a regional scale (Catalonia, northeast of the Iberian Peninsula) by means of multiple regression analysis and spatial interpolation techniques. To perform multiple regression analysis we have used geographical and multiresolution remotely sensed variables as predictors. The geographical variables we have included are altitude, latitude, continentality and solar radiation. As remote sensing predictors, we have selected those variables that are most closely related with air temperature such as albedo, land surface temperature (LST) and NDVI obtained from Landsat‐5 (TM), Landsat‐7 (ETM+), NOAA (AVHRR) and TERRA (MODIS) satellites. The best air temperature models are obtained when remote sensing variables are combined with geographical variables: averaged R2 = 0.60 and averaged root mean square error (RMSE) = 1.75°C for daily temperatures, and averaged R2 = 0.86 and averaged RMSE = 1.00°C for monthly and annual temperatures. The results also show that combined models appear in a higher frequency than only geographical or only remote sensing models (87%, 11% and 2% respectively) and that LST and NDVI are the most powerful remote sensing predictors in air temperature modeling.
Estimation of transboundary transport of pollution aerosols by remote sensing in the eastern Mediterranean
Authors: Rudich Y. , Kaufman Y. J. , Dayan U. , Yu Hongbin , Kleidman R. G.
Published: July 2008

Quantifying transboundary transport of pollution is important for understanding the global distribution of pollution and pollutant burdens in regional and global scales. Using observations from the Moderate resolution Imaging Spectroradiometer (MODIS) on board the Terra and Aqua satellites, the transport of pollution sulfate aerosol was estimated in the eastern Mediterranean. Over a 150 km line west of the Israeli coast, the estimated annual sulfate flux is in a range of 0.025 to 0.062 Tg S a−1. These estimates are consistent with airborne measurements which estimated an annual flux of sulfate of 0.024–0.054 TgS a−1. The MODIS‐based estimates are also in good agreement with estimates of seasonal and annual fluxes from the GOCART model. This case study demonstrates a feasible way to estimate transboundary transport of pollution aerosol by remote sensing means.
Trends in hail in China during 1960–2005
Authors: Xie Baoguo , Zhang Qinghong , Wang Yuqing
Published: July 2008

The annual variation and trend in hail frequency during a 46‐yr period from 1960 to 2005 in China are documented in this study. All analyses are based on a comprehensive collection of observational hail data and operational atmospheric sounding data released by the National Meteorological Information Center (NMIC) of China. The results show no trend in the mean Annual Hail Days (AHD) from 1960 to early 1980s but a significant decreasing trend afterwards. The different trend of the AHD at each station displays a marked regional dependence across China, however. Convective Available Potential Energy (CAPE), strength of vertical wind shear, and mean Freezing‐Level Height (FLH) are analyzed to understand the observed long‐term trends in hail frequency.
Thrombospondins 1 and 2 are Necessary for Synaptic Plasticity and Functional Recovery after Stroke
Authors: Liauw Jason , Hoang Stanley , Choi Michael , Eroglu Cagla , Choi Matthew , Sun Guo-hua , Percy Matthew , Wildman-Tobriner Benjamin , Bliss Tonya , Guzman Raphael G , Barres Ben A , Steinberg Gary K
Published: July 2008

Thrombospondins 1 and 2 (TSP-1/2) belong to a family of extracellular glycoproteins with angiostatic and synaptogenic properties. Although TSP-1/2 have been postulated to drive the resolution of postischemic angiogenesis, their role in synaptic and functional recovery is unknown. We investigated whether TSP-1/2 are necessary for synaptic and motor recovery after stroke. Focal ischemia was induced in 8- to 12-week-old wild-type (WT) and TSP-1/2 knockout (KO) mice by unilateral occlusion of the distal middle cerebral artery and the common carotid artery (CCA). Thrombospondins 1 and 2 increased after stroke, with both TSP-1 and TSP-2 colocalizing mostly to astrocytes. Wild-type and TSP-1/2 KO mice were compared in angiogenesis, synaptic density, axonal sprouting, infarct size, and functional recovery at different time points after stroke. Using the tongue protrusion test of motor function, we observed that TSP-1/2 KO mice exhibited significant deficit in their ability to recover function ( P < 0.05) compared with WT mice. No differences were found in infarct size and blood vessel density between the two groups after stroke. However, TSP-1/2 KO mice exhibited significant synaptic density and axonal sprouting deficits. Deficiency of TSP-1/2 leads to impaired recovery after stroke mainly due to the role of these proteins in synapse formation and axonal outgrowth.
Human pancreatic β-cell glucokinase: subcellular localization and glucose repression signalling function in the yeast cell
Authors: Riera Alberto , Ahuatzi Deifilia , Herrero Pilar , Garcia-Gimeno Maria Adelaida , Sanz Pascual , Moreno Fernando
Published: July 2008

Human GKβ (pancreatic β-cell glucokinase) is the main glucose-phosphorylating enzyme in pancreatic β-cells. It shares several structural, catalytic and regulatory properties with Hxk2 (hexokinase 2) from Saccharomyces cerevisiae. In fact, it has been previously described that expression of GKβ in yeast could replace Hxk2 in the glucose signalling pathway of S. cerevisiae. In the present study we report that GKβ exerts its regulatory role by association with the yeast transcriptional repressor Mig1 (multicopy inhibitor of GAL gene expression 1); the presence of Mig1 allows GKβ to bind to the SUC2 (sucrose fermentation 2) promoter, helping in this way in the maintenance of the repression of the SUC2 gene under high-glucose conditions. Since a similar mechanism has been described for the yeast Hxk2, the findings of the present study suggest that the function of the regulatory domain present in these two proteins has been conserved throughout evolution. In addition, we report that GKβ is enriched in the yeast nucleus of high-glucose growing cells, whereas it shows a mitochondrial localization upon removal of the sugar. However, GKβ does not exit the nucleus in the absence of Mig1, suggesting that Mig1 regulates the nuclear exit of GKβ under low-glucose conditions. We also report that binding of GKβ to Mig1 allows the latter protein to be located at the mitochondrial network under low-glucose conditions.
Glutamine-181 is crucial in the enzymatic activity and substrate specificity of human endoplasmic-reticulum aminopeptidase-1
Authors: Goto Yoshikuni , Tanji Hiroe , Hattori Akira , Tsujimoto Masafumi
Published: July 2008

ERAP-1 (endoplasmic-reticulum aminopeptidase-1) is a multifunctional enzyme with roles in the regulation of blood pressure, angiogenesis and the presentation of antigens to MHC class I molecules. Whereas the enzyme shows restricted specificity toward synthetic substrates, its substrate specificity toward natural peptides is rather broad. Because of the pathophysiological significance of ERAP-1, it is important to elucidate the molecular basis of its enzymatic action. In the present study we used site-directed mutagenesis to identify residues affecting the substrate specificity of human ERAP-1 and identified Gln181 as important for enzymatic activity and substrate specificity. Replacement of Gln181 by aspartic acid resulted in a significant change in substrate specificity, with Q181D ERAP-1 showing a preference for basic amino acids. In addition, Q181D ERAP-1 cleaved natural peptides possessing a basic amino acid at the N-terminal end more efficiently than did the wild-type enzyme, whereas its cleavage of peptides with a non-basic amino acid was significantly reduced. Another mutant enzyme, Q181E, also revealed some preference for peptides with a basic N-terminal amino acid, although it had little hydrolytic activity toward the synthetic peptides tested. Other mutant enzymes, including Q181N and Q181A ERAP-1s, revealed little enzymatic activity toward synthetic or peptide substrates. These results indicate that Gln181 is critical for the enzymatic activity and substrate specificity of ERAP-1.
Effect of different antihypertensive treatments on Ras, MAPK and Akt activation in hypertension and diabetes
Authors: Fernández-Campo Lucas , Grande María T. , Diego Julia , Fuentes-Calvo Isabel , Macías-Núñez Juan F. , Sánchez-Rodríguez Angel , Grande Jesús , García-Ortiz Luis , López-Novoa José M. , Martínez-Salgado Carlos
Published: July 2008

Ras GTPases function as transducers of extracellular signals regulating many cell functions, and they appear to be involved in the development of hypertension. In the present study, we have investigated whether antihypertensive treatment with ARBs (angiotensin II receptor blockers), ACEi (angiotensin-converting enzyme inhibitors) and diuretics induce changes in Ras activation and in some of its effectors [ERK (extracellular-signal-regulated kinase) and Akt] in lymphocytes from patients with hypertension without or with diabetes. ACEi treatment transiently reduced Ras activation in the first month of treatment, but diuretics induced a sustained increase in Ras activation throughout the 3 months of the study. In patients with hypertension and diabetes, ARB, ACEi and diuretic treatment increased Ras activation only during the first week. ACEi treatment increased phospho-ERK expression during the first week and also in the last 2 months of the study; however, diuretic treatment reduced phospho-ERK expression during the last 2 months of the study. In patients with hypertension and diabetes, antihypertensive treatments did not induce changes in phospho-ERK expression in lymphocytes. ACEi treatment reduced phospho-Akt expression in patients with hypertension and diabetes only in the first month of treatment. In conclusion, these findings show that antihypertensive treatments with ACEi, and diuretics to a lesser extent, modify Ras activation and some of its signalling pathways, although in different directions, whereas ARBs do not appear to have any influence on Ras signalling pathways.
Communication and Academic Challenges in Early Adolescence for Children Who Have Been Adopted From the Former Soviet Union
Authors: Beverly Brenda L. , McGuinness Teena M. , Blanton Debra J.
Published: July 2008

Purpose

This was a Time II survey of outcomes for children, now ages 9 to 13 years, who were almost 4 years old on average when they were adopted from the former Soviet Union.

Method

As part of a larger study (see T. McGuinness, R. Ryan, & C. Broadus Robinson, 2005), parents of 55 children (Mage = 11 years) were surveyed regarding their children’s speech-language, behavior, and eligibility for special education. The children’s mean length of institutionalization was 36 months.

Results

A total of 45, or 82%, of the children had at least one special education label. The most frequent was communication disorder, which was reported for 34 children, or 62%. The frequency of attention deficit hyperactivity disorder (ADHD) was high, 42%. The ratio of boys to girls for communication disorders and ADHD was 1.5:1. Girls who were adopted after 36 months of age were 4 times more likely than girls who were adopted before 36 months to be labeled ADHD, and children with low birth weight exhibited learning disabilities twice as often as children with normal birth weight.

Conclusion

Speech-language, learning, and attention deficits for late-adopted, early adolescent children were higher than expected. These children from the former Soviet Union experienced substantial preadoption adversity associated with lengthy orphanage stays and poor care. Gender and low birth weight were also factors.
The Application of Evidence-Based Practice to Nonspeech Oral Motor Treatments
Authors: Lass Norman J. , Pannbacker Mary
Published: July 2008

Purpose

The purpose of this article is to help speech-language pathologists (SLPs) apply the principles of evidence-based practice (EBP) to nonspeech oral motor treatments (NSOMTs) in order to make valid, evidence-based decisions about NSOMTs and thus determine if they are viable treatment approaches for the management of communication disorders.

Method

A detailed description of EBP is provided, including levels of evidence for rating the quality of evidence. NSOMTs are described and a survey of the literature on NSOMTs is provided along with a determination of the level of evidence of each study reported. A systematic literature search was conducted using the electronic databases of MEDLINE and CINAHL (Cumulative Index to Nursing and Allied Health Literature) within an unrestricted time period. In addition, reference lists from identified articles were also reviewed. Ethical and fiscal issues related to EBP and NSOMTs, as well as clinical implications of EBP for the use of NSOMTs, are discussed.

Results

A total of 45 articles/reports were published between 1981 and 2006 in peer-reviewed and non-peer-reviewed journals. Most of the sources (25) relied on weak anecdotal evidence and opinions. Moreover, studies that employed stronger designs reported negative results for NSOMTs (i.e., evidence against the use of NSOMTs for modifying speech).

Conclusion

Despite their use for many years and their popularity among some SLPs for the treatment of a wide variety of speech problems in children and adults, NSOMTs are controversial because sufficient evidence does not exist to support their effectiveness in improving speech. Moreover, limited evidence exists for the use of NSOMTs to facilitate nonspeech activities. Therefore, the available evidence does not support the continued use of NSOMTs as a standard treatment and they should be excluded from use as a mainstream treatment until there are further data. SLPs should consider the principles of EBP in making decisions about NSOMTs.
Optimal vein density in artificial and real leaves
Authors: Noblin X. , Mahadevan L. , Coomaraswamy I. A. , Weitz D. A. , Holbrook N. M. , Zwieniecki M. A.
Published: July 2008

The long evolution of vascular plants has resulted in a tremendous variety of natural networks responsible for the evaporatively driven transport of water. Nevertheless, little is known about the physical principles that constrain vascular architecture. Inspired by plant leaves, we used microfluidic devices consisting of simple parallel channel networks in a polymeric material layer, permeable to water, to study the mechanisms of and the limits to evaporation-driven flow. We show that the flow rate through our biomimetic leaves increases linearly with channel density (1/
d
) until the distance between channels (
d
) is comparable with the thickness of the polymer layer (δ), above which the flow rate saturates. A comparison with the plant vascular networks shows that the same optimization criterion can be used to describe the placement of veins in leaves. These scaling relations for evaporatively driven flow through simple networks reveal basic design principles for the engineering of evaporation–permeation-driven devices, and highlight the role of physical constraints on the biological design of leaves.
A unified view of ligand-protected gold clusters as superatom complexes
Authors: Walter Michael , Akola Jaakko , Lopez-Acevedo Olga , Jadzinsky Pablo D. , Calero Guillermo , Ackerson Christopher J. , Whetten Robert L. , Grönbeck Henrik , Häkkinen Hannu
Published: July 2008

Synthesis, characterization, and functionalization of self-assembled, ligand-stabilized gold nanoparticles are long-standing issues in the chemistry of nanomaterials. Factors driving the thermodynamic stability of well documented discrete sizes are largely unknown. Herein, we provide a unified view of principles that underlie the stability of particles protected by thiolate (SR) or phosphine and halide (PR
3
, X) ligands. The picture has emerged from analysis of large-scale density functional theory calculations of structurally characterized compounds, namely Au
102
(SR)
44
, Au
39
(PR
3
)
14
X
6
−
, Au
11
(PR
3
)
7
X
3
, and Au
13
(PR
3
)
10
X
2
3+
, where X is either a halogen or a thiolate. Attributable to a compact, symmetric core and complete steric protection, each compound has a filled spherical electronic shell and a major energy gap to unoccupied states. Consequently, the exceptional stability is best described by a “noble-gas superatom” analogy. The explanatory power of this concept is shown by its application to many monomeric and oligomeric compounds of precisely known composition and structure, and its predictive power is indicated through suggestions offered for a series of anomalously stable cluster compositions which are still awaiting a precise structure determination.
RBC Aggregation: More Important than RBC Adhesion to Endothelial Cells as a Determinant of In Vivo Blood Flow in Health and Disease
Authors: BASKURT OGUZ K. , MEISELMAN HERBERT J.
Published: July 2008

Although the shear‐dependent and reversible phenomenon of red blood cell (RBC) aggregation has been studied for decades, its role as a determinant of in vivo blood flow in both health and disease has not yet been fully documented. In this brief review, we present compelling arguments, supported by literature evidence, that in vivo flow dynamics are more affected by RBC aggregation than by RBC adhesion to endothelial cells (ECs). A companion article (i.e., a “counter‐point”) published in this issue of the journal argues that in disease states, RBC‐EC adhesion is the more important determinant.
PuReD-MCL: a graph-based PubMed document clustering methodology
Authors: Theodosiou T. , Darzentas N. , Angelis L. , Ouzounis C. A.
Published: July 2008

Motivation: Biomedical literature is the principal repository of biomedical knowledge, with PubMed being the most complete database collecting, organizing and analyzing such textual knowledge. There are numerous efforts that attempt to exploit this information by using text mining and machine learning techniques. We developed a novel approach, called PuReD-MCL (Pubmed Related Documents-MCL), which is based on the graph clustering algorithm MCL and relevant resources from PubMed.

Methods: PuReD-MCL avoids using natural language processing (NLP) techniques directly; instead, it takes advantage of existing resources, available from PubMed. PuReD-MCL then clusters documents efficiently using the MCL graph clustering algorithm, which is based on graph flow simulation. This process allows users to analyse the results by highlighting important clues, and finally to visualize the clusters and all relevant information using an interactive graph layout algorithm, for instance BioLayout Express 3D.

Results: The methodology was applied to two different datasets, previously used for the validation of the document clustering tool TextQuest. The first dataset involves the organisms Escherichia coli and yeast, whereas the second is related to Drosophila development. PuReD-MCL successfully reproduces the annotated results obtained from TextQuest, while at the same time provides additional insights into the clusters and the corresponding documents.

Availability: Source code in perl and R are available from http://tartara.csd.auth.gr/~theodos/

Contact:  theodos@csd.auth.gr
Foliar Symptom Expression in Association with Early Infection and Xylem Colonization by Fusarium virguliforme (formerly F. solani f. sp. glycines), the Causal Agent of Soybean Sudden Death Syndrome
Authors: Navi Shrishail S. , Yang X. B.
Published: June 2008

Soybean sudden death syndrome (SDS), caused by Fusarium virguliforme (FV), is a root disease that results in severe foliar symptoms during the reproductive stage. In a regular growing season, an epidemic of SDS is highly correlated with the planting date and the disease tends to be more severe in earlier planted soybeans. Occurrence of infection early in the season is likely to result in colonization in the xylem and phloem tissues, a process essential for foliar symptom expression because xylem tissues are upward pathways in soybean plants. To demonstrate the biology of this infection, we used an effective and quantifiable seedling inoculation technique in which germinated seeds in a Petri dish were spray-inoculated with conidial suspension before being transplanted. Plants that had foliar symptoms showed both external and internal discolored taproots and basal stems, while plants with no foliar symptoms had only superficial discoloration. Microtome sectioning of taproots of plants that had foliar symptoms revealed the presence of fungal structures in both xylem and phloem tissues, while plants that had no foliar symptoms revealed fungal structures only in phloem tissue. A scanning electron microscope study showed a higher penetration frequency of FV near the root-cap zone where few or no root hairs of the radicle were found. These results indicate that fungal penetration into the xylem tissue plays a role in foliar symptom expression.

Accepted for publication 10 December 2007. Published 22 February 2008.
Adult Corn Earworm (Helicoverpa zea) Susceptibility to Methomyl
Authors: Herbert D. Ames , Malone Sean , Kuhar Thomas P. , Portillo Hector E. , Saienni Joe P. , Williams Robert W.
Published: June 2008

Adult vial testing procedures were used to determine susceptibility of male corn earworm (Helicoverpa zea) to methomyl. Rate response bioassays using 0.39, 0.78, 1.56, 3.12, 6.25, 12.5, and 25 μg ai/vial were conducted using a laboratory colony. Results showed 10, 30, 70, 80, 80, 90, and 100% mortality at these rates. Field-collected moths from pheromone traps in Virginia were assayed at 0.25, 0.5, 1, 2, 5, and 10 times the 25 μg ai/vial rate (100% laboratory colony mortality rate). After 24 h exposure, 3.7 and 2.6% of moths survived the 12.5 and 25 μg ai/vial rates, with 100% mortality at all other rates. These results indicate that future assays should include lower rates in order to establish a baseline rate range for detecting susceptibility or resistance.

Accepted for publication 18 December 2007. Published 12 March 2008.
Filtration to Eliminate Phytophthora spp. from Recirculating Water Systems in Commercial Nurseries
Authors: Ufer Thorsten , Werres Sabine , Posner Martin , Wessels Hans-Peter
Published: June 2008

Three filtration systems using slow sand filtration (SSF) and one using lava grain filtration (LGF) were tested for their ability to eliminate Phytophthora spp. from recycled water in commercial ornamental nurseries over four years. Samples were taken in May, August, and October of each year. Phytophthora spp. could not be detected in any of the filter effluents when filters were operating normally. Water stored in clean water reservoirs that were filled only with filtered water and were well protected from contamination via soil and air remained free of Phytophthora. All four filtration systems produced sufficient quantities of water for nursery production. The maximum annual quantity of water demanded by the nurseries ranged from 30,000 to 163,000 m3. The cost for 1 m3 filtered water was lowest for slow sand filtration compared with lava grain filtration. Recommendations for designing systems suitable for large ornamental nurseries with open air recycling systems are discussed.

Accepted for publication 20 December 2007. Published 14 March 2008.
A Decade of Hop Powdery Mildew in the Pacific Northwest
Authors: Gent David H. , Nelson Mark E. , George Ann E. , Grove Gary G. , Mahaffee Walter F. , Ocamb Cynthia M. , Barbour James D. , Peetz Amy , Turechek William W.
Published: June 2008

Hop powdery mildew, caused by the fungus Podosphaera macularis, was confirmed for the first time in hop yards in the United States Pacific Northwest in 1997. The US hop industry experienced significantly crop loss and damage from the disease, but new knowledge, grower experience, and management approaches have allowed the industry to survive the introduction of this damaging pathogen. This review provides an overview of research on and progress towards economically sustainable management of hop powdery mildew in the US, and future directions for research and further innovation.

Accepted for publication 2 January 2008. Published 14 March 2008.
Biomass Yield Reductions in Switchgrass Due To Smut Caused by Tilletia maclaganii
Authors: Thomsen Paige M. , Brummer E. Charles , Shriver John , Munkvold Gary P.
Published: June 2008

Switchgrass (Panicum virgatum) is an attractive biomass crop for renewable energy, but there is little information on disease losses. Tilletia maclaganii causes a smut disease of switchgrass that results in stunting, premature flowering, and replacement of seeds by fungal sori. We conducted a study in naturally-infested fields to describe the impact of smut on biomass yield. Ten fields were sampled; smut incidence, stand density, and biomass yield were determined. Disease incidence varied from 0.7 to 55.4% (26% overall) and biomass varied from 174 to 617 g/m2. Mean biomass/tiller was significantly reduced by the disease in each field, by 38 to 82%. Yield loss was calculated based on the ratio of mean biomass/tiller for samples (actual yield) and mean biomass/tiller for healthy tillers (attainable yield). Yield loss estimates ranged from 1.7 to 40.1% among the fields. There was a strongly linear relationship (R2 = 0.95) between disease incidence and yield loss, and regression analysis estimated a 0.66% reduction in yield for every 1% increase in disease incidence. According to this model, yield loss for all sampled fields was estimated at 17.0%. This disease is having a significant impact on biomass production in Iowa, and there is a critical need for research on management approaches if switchgrass is to be successful as a feedstock for lignocellulosic ethanol production.

Accepted for publication 2 January 2008. Published 17 March 2008.
Efficacy of Chemical and Biological Agents to Suppress Fusarium and Pythium Damping-Off of Container-Grown Douglas-fir Seedlings
Authors: Linderman Robert G. , Davis E. Anne , Masters Charles J.
Published: June 2008

Douglas-fir seedlings are susceptible to Fusarium or Pythium damping-off that currently is controlled by pre-plant soil fumigation in bareroot nurseries and steam pasteurization or chemical drenches of soilless media in container nurseries. However, because few chemical or biological agents are registered for use on conifer seedlings, we tested several on greenhouse-grown seedlings and found that over-seed applications of Cleary's 3336, Strike, Compass, Compass + Strike, Cygnus, Endura, Medallion, Medallion + Strike, Thiram, and Enzone effectively suppressed pre-emergence damping-off by Fusarium oxysporum, but only Cleary's 3336WP and Medallion + Strike also reduced post-emergence damping-off. Compass, Medallion, and Thiram reduced post-emergence damping-off, but not to a statistically significant level. Pre-emergence damping-off by Pythium irregulare was reduced only by Ranman, but post-emergence damping-off was reduced by Thiram, Hurricane, Ranman, and Subdue MAXX. Over-seed drenches of biological control agents Companion, Kodiak, Subtilex, Taegro, Primastop, SoilGard, Actinovate, Mycostop, RootShield, and Green-Releaf were ineffective in suppressing either Fusarium or Pythium diseases, and combining several agents with chemicals did not improve efficacy. These results provide data in support of registration of some of the effective chemicals, but no biological control agents, for the control of conifer seedling damping-off.

Accepted for publication 14 January 2008. Published 17 March 2008.
Efficacy of Organically Acceptable Fungicides for Management of Early and Late Leaf Spot Diseases on Partially Resistant Peanut Cultivars
Authors: Cantonwine E. G. , Culbreath A. K. , Shew B. B. , Boudreau M. A.
Published: June 2008

Field experiments were carried out in Georgia and North Carolina to evaluate the efficacy of fungicides approved for the organic management of early leaf spot, caused by Cercospora arachidicola, and late leaf spot, caused by Cercosporidium personatum, in peanut (Arachis hypogaea) fields planted to cultivars with partial resistance to one or both pathogens. Copper treatments alone or in mixtures resulted in less disease than a non-treated control. In Georgia, sulfur provided some disease suppression, but not as much as treatments with copper sulfate. Neem oil did not affect disease severity. Mean pod yields across years were significantly greater than the non-treated control only for copper sulfate in Georgia and cupric hydroxide in North Carolina. The minimal yield response to treatments suggests that under similar situations, the frequency of copper-based fungicide applications may be reduced with little affect on yield.

Accepted for publication 16 January 2008. Published 17 March 2008.
Milestones in Fungicide Discovery: Chemistry that Changed Agriculture
Authors: Klittich Carla J.
Published: June 2008

Fungicides have repeatedly altered the way crops are grown and farmers' expectations of crop health. This review focuses on the inventions that were turning points in agriculture and the evolution in our expectations of fungicides.

Accepted for publication 18 December 2007. Published 18 April 2008.
Occurrence and Prevalence of Foliar Diseases on Blueberry in Georgia
Authors: Scherm H. , Savelle A. T. , Brannen P. M. , Krewer G.
Published: June 2008

Qualitative and quantitative information about the occurrence and prevalence of fungal species causing foliar diseases on blueberry in the southeastern United States is limited. To close this knowledge gap, a field survey was conducted in 2002 and 2003 involving a total of 177 samples (cultivar-site-year combinations) from plantings of rabbiteye and southern highbush blueberry cultivars in Georgia. Among eight cultivars, Powderblue was the least affected cultivar whereas Star had high foliar disease levels in both years. Averaged by cultivar and year, there was a significant positive correlation between defoliation and disease severity. Septoria leaf spot and Gloeosporium leaf spot were the most prevalent and most severe foliar diseases, occurring on > 30% of samples in both years. Pestalotia leaf spot, Phyllosticta leaf spot, and leaf rust occurred at intermediate prevalence levels. Among these three diseases, leaf rust was most severe (especially in 2003) whereas Pestalotia leaf spot was associated with secondary infections and occurred mostly on southern highbush cultivars. Algal leaf spot and powdery mildew occurred infrequently and inconsistently. More than 70% of leaf samples, especially from the rabbiteye cultivars, showed symptoms of non-pathogenic leaf damage. The foliar disease complex on blueberry in Georgia is considerably more diverse than previously appreciated.

Accepted for publication 31 January 2008. Published 21 April 2008.
Evaluation of Sorghum Germplasm from China against Claviceps africana, Causal Agent of Sorghum Ergot
Authors: Prom Louis K. , Erpelding John E. , Montes-Garcia Noe
Published: June 2008

Forty Chinese sorghum landraces maintained by the USDA-ARS Plant Genetic Resources Conservation Unit, Griffin, GA were evaluated for ergot resistance at the Texas A&M Research Farm, College Station, Texas, during the 2005 and 2006 growing seasons. The male sterile line, ATx623, was included as a susceptible control and three IS8525 derived lines were included as resistant controls. The disease infection level was low in the susceptible check in 2005 due to unfavorable environmental conditions, but the majority of the Chinese accessions showed a higher level of tolerance than the resistant controls and in contrast, infection severity was high in 2006. The IS8525 resistant controls averaged 25% infection compared to an average infection of 18% for the 40 Chinese accessions. Four Chinese accessions, PI63923, PI511832, PI610749, and PI610688, recorded less than 10% ergot infection and thus, these four accessions may possess genes for ergot resistance. Further research is underway to evaluate these accessions under multi-environments to confirm resistance and to determine if the resistance is associated with pollination characteristics.

Accepted for publication 19 February 2008. Published 19 May 2008.
Reaction of Drought-Tolerant Soybean Genotypes to Macrophomina phaseolina
Authors: Wrather J. A. , Shannon J. G. , Carter T. E. , Bond J. P. , Rupe J. C. , Almeida A. M. R.
Published: June 2008

Charcoal rot caused by Macrophomina phaseolina is a common disease of many crops including common bean and soybean. Incidence and severity of charcoal rot are enhanced when plants are drought stressed. Resistance to this pathogen in some common bean genotypes was associated with drought tolerance. Resistance to M. phaseolina among soybean genotypes has not been identified, although a few have been rated moderately resistant based on less root tissue colonization by this pathogen compared to other genotypes. A few soybean genotypes have been rated as slow-wilt or drought-tolerant. The reaction of drought-tolerant soybean to M. phaseolina compared to intolerant or drought-sensitive genotypes has not been determined. Our objective was to determine if there were differences in root colonization by M. phaseolina between drought-tolerant and drought-sensitive soybean genotypes. Drought tolerance of the soybean genotypes and root colonization by M. phaseolina at the R6 and R8 stages of growth were not related in this study. Some drought-tolerant soybean genotypes may resist root colonization by M. phaseolina, but our results suggest that this is not true for all drought-tolerant genotypes.

Accepted for publication 21 March 2008. Published 18 June 2008.