bluuebunny/crossref_metadata_2025 huggingface dataset:
Atlantic pycnocline theory scrutinized using a coupled climate model
Authors: Levermann Anders , Fürst Johannes Jakob
Published: July 2010

Simulations with changed Southern Ocean wind‐stress, oceanic vertical mixing, surface freshwater forcing and global warming confirm the basic equations of Gnanadesikan's (1999) theory for the Atlantic: one vertical scale, the pycnocline depth D, contributes inversely proportional to low‐latitudinal upwelling and linearly to Southern Ocean eddy transport. The maximum Atlantic overturning is confirmed to be quadratic in D but is also shown to be linear in a meridional density difference Δρ. Our simulations strongly suggest that the theory needs to be complemented by a dynamical equation for Δρ since changes in both D and Δρ are significant and mutually independent. While, under global warming D varies strongly and Δρ is practically constant, the situation is reversed for altered surface freshwater fluxes. Similarly, variations in the meridional length scale of Southern Ocean outcropping require a dynamical equation in order to capture the fundamental behavior of the Atlantic meridional overturning circulation.
Possible interactions between bacterial diversity, microbial activity and supraglacial hydrology of cryoconite holes in Svalbard
Authors: Edwards Arwyn , Anesio Alexandre M , Rassner Sara M , Sattler Birgit , Hubbard Bryn , Perkins William T , Young Michael , Griffith Gareth W
Published: July 2010

The diversity of highly active bacterial communities in cryoconite holes on three Arctic glaciers in Svalbard was investigated using terminal restriction fragment length polymorphism (T-RFLP) of the 16S rRNA locus. Construction and sequencing of clone libraries allowed several members of these communities to be identified, with Proteobacteria being the dominant one, followed by Cyanobacteria and Bacteroidetes. T-RFLP data revealed significantly different communities in holes on the (cold) valley glacier Austre Brøggerbreen relative to two adjacent (polythermal) valley glaciers, Midtre Lovénbreen and Vestre Brøggerbreen. These population compositions correlate with differences in organic matter content, temperature and the metabolic activity of microbial communities concerned. No within-glacier spatial patterns were observed in the communities identified over the 2-year period and with the 1 km-spaced sampling. We infer that surface hydrology is an important factor in the development of cryoconite bacterial communities.
The Effects of Poststroke Captopril and Losartan Treatment on Cerebral Blood Flow Autoregulation in SHRsp with Hemorrhagic Stroke
Authors: Smeda John S , Daneshtalab Noriko
Published: July 2010

The ability of captopril and losartan treatment to restore cerebral blood flow (CBF) autoregulation after intracerebral hemorrhagic stroke (HS) was assessed in Kyoto–Wistar stroke-prone hypertensive rats (SHRsp). Laser Doppler techniques assessed CBF autoregulation in the middle cerebral artery (MCA) perfusion domain and a pressure myograph was used to measure pressure-dependent constriction (PDC) in isolated MCAs before and after stroke and after 13, 33, and 63 days of poststroke captopril or losartan treatment. The treatments did not lower blood pressure (BP) and equally suppressed plasma aldosterone after HS. The HS development was associated with the loss of CBF autoregulation, high CBF, increased CBF conductance to elevations in BP, and the loss of PDC in the MCAs. Both treatments restored these functions to prestroke levels within 13 days. The PDC and CBF autoregulation subsequently deteriorated after 63 days of captopril treatment while being maintained at prestroke levels over all durations of losartan treatment. The SHRsp subjected to 35 days of poststroke losartan treatment exhibited less blood–brain barrier (BBB) disruption and brain herniation than captopril-treated SHRsp. The superior ability of losartan to restore CBF autoregulation and myogenic function may have contributed to the more effective attenuation of cerebral damage after HS.
Impact of Genetic and Renovascular Chronic Arterial Hypertension on the Acute Spatiotemporal Evolution of the Ischemic Penumbra: A Sequential Study with MRI in the Rat
Authors: Letourneur Annelise , Roussel Simon , Toutain Jérôme , Bernaudin Myriam , Touzani Omar
Published: July 2010

Although chronic arterial hypertension (CAH) increases the risk of stroke and the severity of the resultant lesion, it is rarely integrated in preclinical studies. Here, we analyzed the impact of CAH on the acute spatiotemporal evolution of the ischemic penumbra as defined by the perfusion-weighted imaging/diffusion-weighted imaging mismatch. Sequential 7T-MRI examinations were performed from 30 minutes up to 4 hours after permanent cerebral ischemia in genetically hypertensive rats (spontaneously hypertensive rats, SHR), renovascular-hypertensive rats (RH-WKY), and their normotensive controls (Wistar-Kyoto rats, WKY). The apparent diffusion coefficient (ADC)-defined lesion was larger in hypertensive rats than in normotensive animals as early as 30 minutes after the ischemia. The ischemic penumbra was smaller in both genetically and renovascular-hypertensive rats (at 30 minutes; SHR = 66 ± 25 mm3, RH-WKY = 55 ± 17 mm3 versus WKY = 117 ± 14 mm3; P < 0.008) and there was no significant difference between the perfusion deficit and ADC lesion (mismatch definition of penumbra) as early as 90 minutes after the occlusion. Genetic hypertension and induced renovascular hypertension resulted in larger lesion and smaller penumbra that vanished rapidly. These data support the need to integrate CAH in preclinical studies relative to the treatment of stroke, as failure to do so may lead to preclinical results nonpredictive of clinical trials, which include hypertensive patients.
Brillouin scattering study of liquid methane under high pressures and high temperatures
Authors: Li Min , Li Fangfei , Gao Wei , Ma Chunli , Huang Liyin , Zhou Qiang , Cui Qiliang
Published: July 2010

Brillouin scattering measurements were performed on liquid methane using diamond anvil cell along five isotherms and at the pressures up to solidification points. Sound velocity, refractive index, and adiabatic bulk modulus of liquid methane as function of pressure were determined with the measurements from the platelet and backscattering geometries. The maximum pressure and temperature reached up to 5.12 GPa and 539 K. The sound velocity, refractive index, and adiabatic bulk modulus increased with pressure along each isotherm. The equation of state of liquid methane was determined from the present Brillouin results.
Investigation of state retention in metal–ferroelectric–insulator–semiconductor structures based on Langmuir–Blodgett copolymer films
Authors: Reece Timothy J. , Gerber A. , Kohlstedt H. , Ducharme Stephen
Published: July 2010

Among the ferroelectric thin films considered for use in nonvolatile memory devices, the ferroelectric copolymer of polyvinylidene fluoride, PVDF (C2H2F2), with trifluoroethylene, TrFE (C2HF3), has distinct advantages, including low dielectric constant, low processing temperature, relative low cost compared with epitaxial ferroelectric oxides, and compatibility with organic semiconductors. We report the operation and polarization retention properties of a metal–ferroelectric–insulator–semiconductor bistable capacitor memory element consisting of an aluminum gate, a P(VDF-TrFE) Langmuir–Blodgett film, a 30 nm cerium oxide buffer layer, and a moderately doped silicon wafer. The device exhibited a 1.9 V wide hysteresis window obtained with a ±7 V operating range with a state retention time of 10 min. The mechanisms contributing to loss of state retention are discussed.
Insights into the orbital invariance problem in state-specific multireference coupled cluster theory
Authors: Evangelista Francesco A. , Gauss Jürgen
Published: July 2010

In this communication we report the results of our studies on the orbital invariance properties of the state-specific multireference coupled cluster approach suggested by Mukherjee and co-workers (Mk-MRCC). In particular, we have gathered numerical evidence to show that even when the linear excitation manifold is modified in order to span the same space for each reference, the resulting method is not orbital invariant. In order to test this conjecture we have proposed a new truncation scheme (Mk-MRCCSDtq) which, in addition to full single and double excitations, contains partial triple and quadruple excitations. For a reference space generated by all possible combinations of two electrons in two orbitals, the linear excitation manifold of Mk-MRCCSDtq spans the same set for each reference determinant. Mk-MRCCSDtq is found to lack energy invariance for rotations among active molecular orbitals but it is less sensitive to orbital rotations than the conventional scheme which includes only singles and doubles (Mk-MRCCSD). Nevertheless, Mk-MRCCSDtq is a very accurate method, superior with respect to multireference configuration interaction approaches, and competitive with the active-space coupled cluster method and the MRexpT ansatz.
Determination of spin Hamiltonians from projected single reference configuration interaction calculations. I. Spin 1/2 systems
Authors: Monari A. , Maynau D. , Malrieu J.-P.
Published: July 2010

The most reliable wave-function based treatments of magnetic systems usually start from a complete active space self-consistent field calculation of the magnetic electrons in the magnetic orbitals, followed by extensive and expensive configuration interaction (CI) calculations. This second step, which introduces crucial spin polarization and dynamic correlation effects, is necessary to reach reliable values of the magnetic coupling constants. The computational cost of these approaches increases exponentially with the number of unpaired electrons. The single-determinantal unrestricted density functional Kohn–Sham calculations are computationally much simpler, and may provide reasonable estimates of these quantities, but their results are strongly dependent on the chosen exchange-correlation potential. The present work, which may be seen as an ab initio transcription of the unrestricted density functional theory technique, returns to the perturbative definition of the Heisenberg Hamiltonian as an effective Hamiltonian, and proposes a direct estimate of its diagonal energies through single reference CI calculations. The differences between these diagonal terms actually determine the entire Heisenberg Hamiltonian. The reference determinants must be vectors of the model space and the components on the other vectors of the model space are cancelled along the iterative process. The method is successfully tested on a series of bicentric and multicentric spin 12 systems. The projected single reference difference dedicated CI treatment is both accurate and of moderate cost. It opens the way to parameter-free calculations of large spin assemblies.
Accurate calculations of the hydration free energies of druglike molecules using the reference interaction site model
Authors: Palmer David S. , Sergiievskyi Volodymyr P. , Jensen Frank , Fedorov Maxim V.
Published: July 2010

We report on the results of testing the reference interaction site model (RISM) for the estimation of the hydration free energy of druglike molecules. The optimum model was selected after testing of different RISM free energy expressions combined with different quantum mechanics and empirical force-field methods of structure optimization and atomic partial charge calculation. The final model gave a systematic error with a standard deviation of 2.6 kcal/mol for a test set of 31 molecules selected from the SAMPL1 blind challenge set [J. P. Guthrie, J. Phys. Chem. B 113, 4501 (2009)]. After parametrization of this model to include terms for the excluded volume and the number of atoms of different types in the molecule, the root mean squared error for a test set of 19 molecules was less than 1.2 kcal/mol.
rf power system for thrust measurements of a helicon plasma source
Authors: Kieckhafer Alexander W. , Walker Mitchell L. R.
Published: July 2010

A rf power system has been developed, which allows the use of rf plasma devices in an electric propulsion test facility without excessive noise pollution in thruster diagnostics. Of particular importance are thrust stand measurements, which were previously impossible due to noise. Three major changes were made to the rf power system: first, the cable connection was changed from a balanced transmission line to an unbalanced coaxial line. Second, the rf power cabinet was placed remotely in order to reduce vibration-induced noise in the thrust stand. Finally, a relationship between transmission line length and rf was developed, which allows good transmission of rf power from the matching network to the helicon antenna. The modified system was tested on a thrust measurement stand and showed that rf power has no statistically significant contribution to the thrust stand measurement.
Phonon Raman scattering of perovskite LaNiO3 thin films
Authors: Chaban N. , Weber M. , Pignard S. , Kreisel J.
Published: July 2010

We report an investigation of perovskite-type LaNiO3 thin films by Raman scattering in both various scattering configurations and as a function of temperature. The room-temperature Raman spectra and the associated phonon mode assignment provide reference data for phonon calculations and for the use of Raman scattering for structural investigations of LaNiO3, namely, the effect of strain in thin films or heterostructures. The temperature-dependent Raman spectra from 80 to 900 K are characterized by the softening of the rotational A1g mode, which suggests a decreasing rhombohedral distortion toward the ideal cubic structure with increasing temperature.
Optical properties of graphene nanoribbon in a spatially modulated magnetic field
Authors: Wu Jhao-Ying , Chen Li-Han , Li To-Sing , Lin Ming-Fa
Published: July 2010

The low-frequency optical response of graphene nanoribbons can be enhanced and tuned by a spatially modulated magnetic field. The absorption spectrum exhibits rich asymmetric peaks corresponding to the oscillatory behavior in energy bands. The optical selection rule, dominated by magnetic and quantum confinements, is clarified by examining state wave functions. The dependence of the optical excitations on field strength and period is studied as well. These results provide possibility for employing graphene nanoribbons in future optoelectronic applications.
Terahertz near-field microspectroscopy
Authors: Knab J. R. , Adam A. J. L. , Chakkittakandy R. , Planken P. C. M.
Published: July 2010

Using near-field, terahertz time-domain spectroscopy (THz-TDS), we investigate how the addition of a dielectric material into a subwavelength-diameter, cylindrical waveguide affects its transmission properties. The THz electric near-field is imaged with deep subwavelength resolution as it emerges from filled and unfilled waveguides. Spectroscopic data measured for waveguides filled with polycrystalline D-tartaric acid, and with polyethylene and silicon powders, illustrate the feasibility of this approach for obtaining spectroscopic information from a tiny sample volume.
HIF-2α deletion promotes Kras-driven lung tumor development
Authors: Mazumdar Jolly , Hickey Michele M. , Pant Dhruv K. , Durham Amy C. , Sweet-Cordero Alejandro , Vachani Anil , Jacks Tyler , Chodosh Lewis A. , Kissil Joseph L. , Simon M. Celeste , Keith Brian
Published: July 2010

Non-small cell lung cancer (NSCLC) is the leading cause of cancer deaths worldwide. The oxygen-sensitive hypoxia inducible factor (HIF) transcriptional regulators HIF-1α and HIF-2α are overexpressed in many human NSCLCs, and constitutive HIF-2α activity can promote murine lung tumor progression, suggesting that HIF proteins may be effective NSCLC therapeutic targets. To investigate the consequences of inhibiting HIF activity in lung cancers, we deleted
Hif-1
α or
Hif-2
α in an established Kras
G12D
-driven murine NSCLC model. Deletion of
Hif-1
α had no obvious effect on tumor growth, whereas
Hif-2
α deletion resulted in an unexpected increase in tumor burden that correlated with reduced expression of the candidate tumor suppressor gene
Scgb3a1
(
HIN-1
). Here, we identify
Scgb3a1
as a direct HIF-2α target gene and demonstrate that HIF-2α regulates
Scgb3a1
expression and tumor formation in human Kras
G12D
-driven NSCLC cells. AKT pathway activity, reported to be repressed by Scgb3a1, was enhanced in HIF-2α-deficient human NSCLC cells and xenografts. Finally, a direct correlation between
HIF-2
α and
SCGB3a1
expression was observed in approximately 70% of human NSCLC samples analyzed. These data suggest that, whereas HIF-2α overexpression can contribute to NSCLC progression, therapeutic inhibition of HIF-2α below a critical threshold may paradoxically promote tumor growth by reducing expression of tumor suppressor genes, including
Scgb3a1
.
Hydration-controlled bacterial motility and dispersal on surfaces
Authors: Dechesne Arnaud , Wang Gang , Gülez Gamze , Or Dani , Smets Barth F.
Published: July 2010

Flagellar motility, a mode of active motion shared by many prokaryotic species, is recognized as a key mechanism enabling population dispersal and resource acquisition in microbial communities living in marine, freshwater, and other liquid-replete habitats. By contrast, its role in variably hydrated habitats, where water dynamics result in fragmented aquatic habitats connected by micrometric films, is debated. Here, we quantify the spatial dynamics of
Pseudomonas putida
KT2440 and its nonflagellated isogenic mutant as affected by the hydration status of a rough porous surface using an experimental system that mimics aquatic habitats found in unsaturated soils. The flagellar motility of the model soil bacterium decreased sharply within a small range of water potential (0 to −2 kPa) and nearly ceased in liquid films of effective thickness smaller than 1.5 μm. However, bacteria could rapidly resume motility in response to periodic increases in hydration. We propose a biophysical model that captures key effects of hydration and liquid-film thickness on individual cell velocity and use a simple roughness network model to simulate colony expansion. Model predictions match experimental results reasonably well, highlighting the role of viscous and capillary pinning forces in hindering flagellar motility. Although flagellar motility seems to be restricted to a narrow range of very wet conditions, fitness gains conferred by fast surface colonization during transient favorable periods might offset the costs associated with flagella synthesis and explain the sustained presence of flagellated prokaryotes in partially saturated habitats such as soil surfaces.
Prioritizing Healthcare Worker Vaccinations on the Basis of Social Network Analysis
Authors: Polgreen Philip M. , Tassier Troy Leo , Pemmaraju Sriram Venkata , Segre Alberto Maria
Published: July 2010

Objective.

To use social network analysis to design more effective strategies for vaccinating healthcare workers against influenza.

Design.

An agent-based simulation.

Setting.

A simulation based on a 700-bed hospital.

Methods.

We first observed human contacts (defined as approach within approximately 0.9 m) performed by 15 categories of healthcare workers (eg, floor nurses, intensive care unit nurses, staff physicians, phlebotomists, and respiratory therapists). We then constructed a series of contact graphs to represent the social network of the hospital and used these graphs to run agent-based simulations to model the spread of influenza. A targeted vaccination strategy that preferentially vaccinated more “connected” healthcare workers was compared with other vaccination strategies during simulations with various base vaccination rates, vaccine effectiveness, probability of transmission, duration of infection, and patient length of stay.

Results.

We recorded 6,654 contacts by 148 workers during 606 hours of observations from January through December 2006. Unit clerks, X-ray technicians, residents and fellows, transporters, and physical and occupational therapists had the most contacts. When repeated contacts with the same individual were excluded, transporters, unit clerks, X-ray technicians, physical and occupational therapists, and social workers had the most contacts. Preferentially vaccinating healthcare workers in more connected job categories yielded a substantially lower attack rate and fewer infections than a random vaccination strategy for all simulation parameters.

Conclusions.

Social network models can be used to derive more effective vaccination policies, which are crucial during vaccine shortages or in facilities with low vaccination rates. Local vaccination priorities can be determined in any healthcare facility with only a modest investment in collection of observational data on different types of healthcare workers. Our findings and methods (ie, social network analysis and computational simulation) have implications for the design of effective interventions to control a broad range of healthcare-associated infections.
The BNIP-2 and Cdc42GAP Homology (BCH) Domain of p50RhoGAP/Cdc42GAP Sequesters RhoA from Inactivation by the Adjacent GTPase-activating Protein Domain
Authors: Zhou Yi Ting , Chew Li Li , Lin Sheng-cai , Low Boon Chuan
Published: July 2010

The BNIP-2 and Cdc42GAP homology (BCH) domain is a novel regulator for Rho GTPases, but its impact on p50-Rho GTPase-activating protein (p50RhoGAP or Cdc42GAP) in cells remains elusive. Here we show that deletion of the BCH domain from p50RhoGAP enhanced its GAP activity and caused drastic cell rounding. Introducing constitutively active RhoA or inactivating GAP domain blocked such effect, whereas replacing the BCH domain with endosome-targeting SNX3 excluded requirement of endosomal localization in regulating the GAP activity. Substitution with homologous BCH domain from Schizosaccharomyces pombe, which does not bind mammalian RhoA, also led to complete loss of suppression. Interestingly, the p50RhoGAP BCH domain only targeted RhoA, but not Cdc42 or Rac1, and it was unable to distinguish between GDP and the GTP-bound form of RhoA. Further mutagenesis revealed a RhoA-binding motif (residues 85-120), which when deleted, significantly reduced BCH inhibition on GAP-mediated cell rounding, whereas its full suppression also required an intramolecular interaction motif (residues 169-197). Therefore, BCH domain serves as a local modulator in cis to sequester RhoA from inactivation by the adjacent GAP domain, adding to a new paradigm for regulating p50RhoGAP signaling.
Phosphorylation of eIF2α at Serine 51 Is an Important Determinant of Cell Survival and Adaptation to Glucose Deficiency
Authors: Muaddi Hala , Majumder Mithu , Peidis Philippos , Papadakis Andreas I. , Holcik Martin , Scheuner Donalyn , Kaufman Randal J. , Hatzoglou Maria , Koromilas Antonis E.
Published: July 2010

Various forms of stress induce pathways that converge on the phosphorylation of the alpha (α) subunit of eukaryotic translation initiation factor eIF2 at serine 51 (S51), a modification that results in a global inhibition of protein synthesis. In many cases eIF2α phosphorylation is a biological response that facilitates cells to cope with stressful environments. Glucose deficiency, an important form of stress, is associated with an induction of apoptosis. Herein, we demonstrate that eIF2α phosphorylation is a key step in maintaining a balance between the life and death of a glucose-deficient cell. That is, eIF2α phosphorylation acts as a molecular switch that shifts cells from a proapoptotic to a cytoprotective state in response to prolonged glucose deficiency. This adaptation process is associated with the timely expression of proteins and activation of pathways with significant contributions to cell survival and adaptation including the X-linked inhibitor of apoptosis protein (XIAP). We also show that among the eIF2α kinases GCN2 plays a proapoptotic role whereas PERK and PKR play a cytoprotective one in response to glucose deficiency. Our data demonstrate that eIF2α phosphorylation is a significant determinant of survival and adaptation of glucose-deficient cells with possible important implications in biological processes that interfere with glucose metabolism.
Rho and Anillin-dependent Control of mDia2 Localization and Function in Cytokinesis
Authors: Watanabe Sadanori , Okawa Katsuya , Miki Takashi , Sakamoto Satoko , Morinaga Tomoko , Segawa Kohei , Arakawa Takatoshi , Kinoshita Makoto , Ishizaki Toshimasa , Narumiya Shuh
Published: July 2010

Diaphanous-related formin, mDia, is an actin nucleation/polymerization factor functioning downstream of the small GTPase Rho. Although Rho is critically involved in cytokinesis, it remains elusive how Rho effectors and other regulators of cytoskeletons work together to accomplish this process. Here we focused on mDia2, an mDia isoform involved in cytokinesis of NIH 3T3 cells, and analyzed mechanisms of its localization in cytokinesis. We found that targeting of mDia2 to the cleavage furrow requires not only its binding to RhoA but also its diaphanous-inhibitory domain (DID). We then performed pulldown assays using a fragment containing the latter domain as a bait and identified anillin as a novel mDia2 interaction partner. The anillin-binding is competitive with the diaphanous autoregulatory domain (DAD) of mDia2 in its autoinhibitory interaction. A series of RNA interference and functional rescue experiments has revealed that, in addition to the Rho GTPase-mediated activation, the interaction between mDia2 and anillin is required for the localization and function of mDia2 in cytokinesis.
Functional Relationship between Protein Disulfide Isomerase Family Members during the Oxidative Folding of Human Secretory Proteins
Authors: Rutkevich Lori A. , Cohen-Doyle Myrna F. , Brockmeier Ulf , Williams David B.
Published: July 2010

To examine the relationship between protein disulfide isomerase family members within the mammalian endoplasmic reticulum, PDI, ERp57, ERp72, and P5 were depleted with high efficiency in human hepatoma cells, either singly or in combination. The impact was assessed on the oxidative folding of several well-characterized secretory proteins. We show that PDI plays a predominant role in oxidative folding because its depletion delayed disulfide formation in all secretory proteins tested. However, the phenotype was surprisingly modest suggesting that other family members are able to compensate for PDI depletion, albeit with reduced efficacy. ERp57 also exhibited broad specificity, overlapping with that of PDI, but with preference for glycosylated substrates. Depletion of both PDI and ERp57 revealed that some substrates require both enzymes for optimal folding and, furthermore, led to generalized protein misfolding, impaired export from the ER, and degradation. In contrast, depletion of ERp72 or P5, either alone or in combination with PDI or ERp57 had minimal impact, revealing a narrow substrate specificity for ERp72 and no detectable role for P5 in oxidative protein folding.
A fast and robust statistical test based on likelihood ratio with Bartlett correction to identify Granger causality between gene sets
Authors: Fujita André , Kojima Kaname , Patriota Alexandre G. , Sato João R. , Severino Patricia , Miyano Satoru
Published: July 2010

Summary: We propose a likelihood ratio test (LRT) with Bartlett correction in order to identify Granger causality between sets of time series gene expression data. The performance of the proposed test is compared to a previously published bootstrap-based approach. LRT is shown to be significantly faster and statistically powerful even within non-Normal distributions. An R package named gGranger containing an implementation for both Granger causality identification tests is also provided.

Availability:  http://dnagarden.ims.u-tokyo.ac.jp/afujita/en/doku.php?id=ggranger.

Contact:  andrefujita@riken.jp

Supplementary information:  Supplementary data are available at Bioinformatics online.
Evaluation of Soil Solarization and Flooding As Management Tools for Fusarium Wilt of Lettuce
Authors: Matheron Michael E. , Porchas Martin
Published: July 2010

Fusarium wilt of lettuce caused by Fusarium oxysporum f. sp. lactucae continues to spread and cause economic losses in Arizona lettuce fields since the initial discovery of the disease in the state in 2001. Studies were initiated to assess the potential of summer soil solarization and flooding as management tools for Fusarium wilt of lettuce in southwestern Arizona production fields. In microplot studies, lettuce plant growth in soil naturally infested with F. oxysporum f. sp. lactucae that was solarized from 2 to 8 weeks was consistently greater than growth in nonsolarized soil. Growth of lettuce in flooded soil containing the pathogen occasionally was significantly higher than in nonflooded soil; however, the effect on plant growth and health was not as consistent as that recorded for solarized soil. In four trials within a field containing F. oxysporum f. sp. lactucae, the incidence of Fusarium wilt on lettuce sown in soil after solarization was reduced from 42 to 91% compared with disease in nonsolarized plots. There was no significant benefit of a 2- over a 1-month solarization period under the conditions of these trials, where the mean soil temperature at a depth of 5 cm during a 1-month solarization period in 2005 and 2006 was 47 and 49°C, respectively. These findings suggest that soil solarization can be an effective tool for management of Fusarium wilt on lettuce, especially when used within an integrated program in conjunction with existing disease management tactics.
The function of nonlinear phenomena in meerkat alarm calls
Authors: Townsend Simon W. , Manser Marta B.
Published: July 2010

Nonlinear vocal phenomena are a ubiquitous feature of human and non-human animal vocalizations. Although we understand how these complex acoustic intrusions are generated, it is not clear whether they function adaptively for the animals producing them. One explanation is that nonlinearities make calls more unpredictable, increasing behavioural responses and ultimately reducing the chances of habituation to these call types. Meerkats (
Suricata suricatta
) exhibit nonlinear subharmonics in their predator alarm calls. We specifically tested the ‘unpredictability hypothesis’ by playing back naturally occurring nonlinear and linear medium-urgency alarm call bouts. Results indicate that subjects responded more strongly and foraged less after hearing nonlinear alarm calls. We argue that these findings support the unpredictability hypothesis and suggest this is the first study in animals or humans to show that nonlinear vocal phenomena function adaptively.
The distribution of fitness effects of new beneficial mutations inPseudomonas fluorescens
Authors: McDonald Michael J. , Cooper Tim F. , Beaumont Hubertus J. E. , Rainey Paul B.
Published: July 2010

Theoretical studies of adaptation emphasize the importance of understanding the distribution of fitness effects (DFE) of new mutations. We report the isolation of 100 adaptive mutants—without the biasing influence of natural selection—from an ancestral genotype whose fitness in the niche occupied by the derived type is extremely low. The fitness of each derived genotype was determined relative to a single reference type and the fitness effects found to conform to a normal distribution. When fitness was measured in a different environment, the rank order changed, but not the shape of the distribution. We argue that, even with detailed knowledge of the genetic architecture underpinning the adaptive types (as is the case here), the DFEs remain unpredictable, and we discuss the possibility that general explanations for the shape of the DFE might not be possible in the absence of organism-specific biological details.
New directions in management strategy evaluation through cross-fertilization between fisheries science and terrestrial conservation
Authors: Milner-Gulland E. J. , Arroyo Beatriz , Bellard Celine , Blanchard Julia , Bunnefeld Nils , Delibes-Mateos Miguel , Edwards Charles , Nuno Ana , Palazy Lucille , Reljic Slaven , Riera Pere , Skrbinsek Tomaz
Published: July 2010

On 1 and 2 June 2010, an international meeting was held at the University of Paris Sud XI, France, organized within the framework of the EU FP7 consortium project HUNT, to bring together fisheries and conservation scientists to discuss a unified framework for the future of management strategies for harvested species.
Vibration of spinning discs and powder formation in centrifugal atomization
Authors: Deng Huaxia , Ouyang Huajiang
Published: July 2010

Spinning discs with liquid film on the surface have numerous applications in many industrial processes and have attracted a lot of investigations. Centrifugal atomization of metallic melts using a spinning disc is an efficient process for powder production and spray deposition, which is a typical example of a spinning disc interacting with a liquid film. In this paper, the vibration of an atomizing disc excited by a moving melt is analysed and the role of vibration in the disintegration of the melt film on atomizing discs is then investigated. A dynamic model of the atomizing disc as a spinning Kirchhoff plate is established with moving melt film treated as a moving load on the disc and as an unstable growing wave interacting with the surrounding air outside the disc. The powder size is analysed theoretically and then compared with experimental results. It is found that the predicted results agree with the experimental results very well in the film disintegration mode. Furthermore, the influences of the atomizer parameters on the melt break up and powder size are discussed. The control parameters in the centrifugal atomization are identified, which can provide guidance for atomizer designs.
Quantum statistics on graphs
Authors: Harrison J. M. , Keating J. P. , Robbins J. M.
Published: July 2010

Quantum graphs are commonly used as models of complex quantum systems, for example molecules, networks of wires and states of condensed matter. We consider quantum statistics for indistinguishable spinless particles on a graph, concentrating on the simplest case of Abelian statistics for two particles. In spite of the fact that graphs are locally one dimensional, anyon statistics emerge in a generalized form. A given graph may support a family of independent anyon phases associated with topologically inequivalent exchange processes. In addition, for sufficiently complex graphs, there appear new discrete-valued phases. Our analysis is simplified by considering combinatorial rather than metric graphs—equivalently, a many-particle tight-binding model. The results demonstrate that graphs provide an arena in which to study new manifestations of quantum statistics. Possible applications include topological quantum computing, topological insulators, the fractional quantum Hall effect, superconductivity and molecular physics.
Ethylene-Induced Stabilization of ETHYLENE INSENSITIVE3 and EIN3-LIKE1 Is Mediated by Proteasomal Degradation of EIN3 Binding F-Box 1 and 2 That Requires EIN2 in Arabidopsis
Authors: An Fengying , Zhao Qiong , Ji Yusi , Li Wenyang , Jiang Zhiqiang , Yu Xiangchun , Zhang Chen , Han Ying , He Wenrong , Liu Yidong , Zhang Shuqun , Ecker Joseph R. , Guo Hongwei
Published: July 2010

Plant responses to ethylene are mediated by regulation of EBF1/2-dependent degradation of the ETHYLENE INSENSITIVE3 (EIN3) transcription factor. Here, we report that the level of EIL1 protein is upregulated by ethylene through an EBF1/2-dependent pathway. Genetic analysis revealed that EIL1 and EIN3 cooperatively but differentially regulate a wide array of ethylene responses, with EIL1 mainly inhibiting leaf expansion and stem elongation in adult plants and EIN3 largely regulating a multitude of ethylene responses in seedlings. When EBF1 and EBF2 are disrupted, EIL1 and EIN3 constitutively accumulate in the nucleus and remain unresponsive to exogenous ethylene application. Further study revealed that the levels of EBF1 and EBF2 proteins are downregulated by ethylene and upregulated by silver ion and MG132, suggesting that ethylene stabilizes EIN3/EIL1 by promoting EBF1 and EBF2 proteasomal degradation. Also, we found that EIN2 is indispensable for mediating ethylene-induced EIN3/EIL1 accumulation and EBF1/2 degradation, whereas MKK9 is not required for ethylene signal transduction, contrary to a previous report. Together, our studies demonstrate that ethylene similarly regulates EIN3 and EIL1, the two master transcription factors coordinating myriad ethylene responses, and clarify that EIN2 but not MKK9 is required for ethylene-induced EIN3/EIL1 stabilization. Our results also reveal that EBF1 and EBF2 act as essential ethylene signal transducers that by themselves are subject to proteasomal degradation.
HIV‐negative case of bacillary angiomatosis with chronic hepatitis B
Authors: KAÇAR Nida , TAŞLI Levent , DEMIRKAN Neşe , ERGIN Çağrı , ERGIN Şeniz
Published: July 2010

Bacillary angiomatosis (BA) is an infectious disease which occurs predominantly in immunosuppressive patients and rarely in immunocompetent individuals. We had a case of BA who presented with a red cutaneous nodule on his left leg of which histopathological examination revealed marked lobular proliferation of capillaries throughout the interstitium and clusters of bacilli with hematoxylin–eosin and Warthin–Starry stains, respectively. Antibody titer against Bartonella henselae was 1/32. The only systemic disease the patient had was chronic hepatitis B. HIV was negative and no other immunosuppressive status was established. In this case we believe that the immunological differences secondary to chronic hepatitis B could have caused a tendency for the disease development.
Pilomatrix carcinoma arising from pilomatricoma after 10‐year senescent period: Immunohistochemical analysis
Authors: NISHIOKA Megumi , TANEMURA Atsushi , YAMANAKA Takashi , TANI Mamori , MIURA Hiroyuki , ASAKURA Makiko , TAMAI Nobuyuki , KATAYAMA Ichiro
Published: July 2010

Pilomatrix carcinoma is a rare malignant counterpart of pilomatricoma. To our knowledge, only approximately 90 cases have been published in English literature. Pilomatrix carcinoma is locally aggressive and occasionally shows rapid progression infiltrating to the muscle, bone and vessels. We report a case of pilomatrix carcinoma that developed in a 38‐year‐old man and started to grow after a long stable period, relapsed for a short time and infiltrated into the muscle underneath. While the initial skin biopsy showed histopathological findings consistent with pilomatricoma, the recurrent tumor contained marked cellular atypia and an aggressive growth pattern. Although it is still controversial whether pilomatrix carcinoma arises de novo or through malignant transformation of a pilomatricoma, the present case might be caused by the latter process considering the patient’s clinical course. β‐catenin is a downstream effecter in the canonical pathway of Wnt, acting as a signal for cell differentiation and proliferation. The characteristic nuclear staining pattern of β‐catenin in the basaloid tumor cells, which is usually observed in pilomatrix carcinoma, supported the diagnosis of pilomatrix carcinoma in the present case.
Maturation pathway of metalloprotease produced by Aeromonas sobria
Authors: Takahashi Eizo , Fujii Yoshio , Kobayashi Hidetomo , Yamanaka Hiroyasu , Nair Gopinath Balakrish , Takeda Yoshifumi , Arimoto Sakae , Negishi Tomoe , Okamoto Keinosuke
Published: July 2010

Previously, we cloned the metalloprotease gene of Aeromonas sobria (amp) and determined its nucleotide sequence (GenBank accession number DQ784565). The protease is composed of 591 amino acid residues. In this study, we purified the mature metalloprotease from the culture supernatant of A. sobria and determined the amino terminal sequence and molecular size of AMP. In addition, we examined the production of AMP diachronically and found that AMP emerges outside of the cell as an intermediate composed of mature and propeptide regions. Subsequently, we determined that the N‐terminal amino acid sequence of the intermediate and found that the sequence is identical to that of the mature metalloprotease. This means that the intermediate is composed of a mature AMP region and a C‐terminal propeptide. The cross culture experiment of mutants of metalloprotease and serine protease of A. sobria on skim milk agar medium indicates that the intermediate released outside of the cell is inactive and that serine protease produced by A. sobria accelerates the conversion of the intermediate from the inactive to the active form.
Alterations of CD4+CD25+Foxp3+ regulatory T cells in HIV‐infected slow progressors of former blood donors in China
Authors: Zhang Zining , Jiang Yongjun , Zhang Min , Liu Jing , Sun Guoquan , Shi Wanying , Wang Yanan , Shang Hong
Published: July 2010

Our objective was to study the alterations of CD4+CD25+Foxp3+ Tregs in HIV‐infected SPs and to examine the role of Tregs in the disease progression of HIV. The proportion of CD4+CD25+Foxp3+ Tregs in peripheral blood of 24 SPs, 30 asymptomatic HIV‐infected patients, 20 AIDS patients, and 16 non‐infected controls was quantified using flow cytometry. HIV Gag peptide mix‐induced IFN‐γ expression in CD8+ T cells in whole and CD25‐depleted PBMCs was examined to evaluate the function of Tregs. The expression of CTLA‐4 in Tregs was also detected to measure the suppressive effect of Tregs. HLA‐DR and CD38 expression were measured to study the relationship between the frequency of Tregs and immune activation of HIV‐infected patients. The frequency of CD4+CD25+Foxp3+ regulatory T cells in SPs was lower than in asymptomatic HIV‐infected patients, AIDS patients, and normal controls (P < 0.05). Tregs in SPs showed lower intracellular CTLA‐4 expression than those of asymptomatic HIV‐infected patients and AIDS patients (P < 0.05). The frequency of Tregs significantly correlated with the percentage of CD38 expression on CD4+ and CD8+ T cells (P < 0.05). Multivariate regression analysis showed that the CD4+ T cell count was the strongest independent factor correlated with the absolute count of Tregs, while viral load had the strongest predictive strength on the proportion of Tregs. We conclude that a lower frequency of Tregs and intracellular CTLA‐4 expression of Tregs was one of the characteristics of SPs that may have important clinical impacts for the prediction of the clinical progress of HIV infection.
The efficacy of tobramycin in the treatment of ulcerative colitis
Authors: BURKE D. A. , AXON A. T. R. , CLAYDEN S. A. , DIXON M. F. , JOHNSTON D. , LACEY R. W.
Published: July 2010

This paper reports a double‐blind placebo‐controlled trial of oral tobramycin in acute ulcerative colitis. Eighty‐four patients with an acute relapse of ulcerative colitis were randomized to receive oral tobramycin or placebo for 1 week as an adjunct to steroid therapy. At endpoint, 31 of 42 (74%) in the tobramycin group achieved complete symptomatic remission compared with 18 of 42 (43%) in the placebo group (P= 0.008). The tobramycin group achieved better histological scores (P < 0.05) at endpoint. These findings show that treatment with oral tobramycin improves the short‐term outcome of patients with ulcerative colitis in relapse.
Effects of sulphasalazine and its metabolites on neutrophil chemotaxis, superoxide production, degranulation and translocation of cytochrome b‐245
Authors: WANDALL J. H.
Published: July 2010

This study describes effects of sulphasalazine, 5‐amino‐salicylic acid (5‐ASA) and sulphapyridine on polymorphonuclear neutrophils. Chemotaxis by polymorphonuclear neutrophils incubated with 5‐ASA was reduced in a concentration dependent fashion (10−5‐10−4 M). Degranulation and release of lysozyme and ß‐glucuronidase by activated polymorphonuclear neutrophils was inhibited by sulphasalazine but increased after incubation with 5‐ASA (P < 0.01). Production of O2− was inhibited by sulphasalazine (IC50: 2 × 10−4 M) and to a lesser extent by 5‐ASA (IC50: 10−3 M). Using a cell‐free system sulphasalazine was found to be a strong scavenger and 5‐ASA and sulphapyridine had only weak effects. Superoxide anion production requires translocation of a cytochrome b‐245 and this translocation was reduced by sulphasalazine (P < 0.01) but not by 5‐ASA or sulphapyridine. In conclusion, the intact sulphasalazine molecule has an action of its own and marked differences exist between the action of sulphasalazine and 5‐ASA, which may be important for the clinical activity.
A pharmacokinetic study of sulphasalazine and two new formulations of mesalazine
Authors: SWIFT G. L. , MILLS C. M. , RHODES J. , EVANS B. K. , BENNETT A. , TAVARES I. A.
Published: July 2010

We have examined the pharmacokinetics of enteric coated sulphasalazine compared with two new formulations of mesalazine. These consisted of microgranules of mesalazine coated with Eudragit S in a concentration of either 20 or 25% dry lacquer substance; these in turn were enclosed in capsules coated with Eudragit L.

In‐vitro dissolution studies of coated microgranules showed that drug release was pH dependent. Studies in 7 normal volunteers showed median peak concentrations of 5‐amino‐salicylic acid and N‐acetyl‐5‐amino‐salicylic acid occurred at about 6 hours with both microgranular preparations, compared with sulphasalazine at 15 h. The microgranule formulation coated with 20% Eudragit S gave serum levels and overall systemic absorption similar to values with sulphasalazine. This new formulation may be of value for delivering mesalazine and other therapeutic agents to the colon.
The continuing development of gastric acid pump inhibitors
Authors: SACHS G. , SHIN J. M. , BESANCON M. , PRINZ C.
Published: July 2010

The synthesis and action of H2‐receptor antagonists changed the understanding of gastric acid secretion as well as changing medical therapy for peptic ulcer disease. It is now known that peripheral regulation of gastric acid secretion depends largely, but not entirely, on histamine release from the enterochromaffin‐like cell. There is, therefore, no final common pathway for stimulation of the parietal cell. In contrast, all stimuli converge to activate the acid pump, the H+, K+‐ATPase. Inhibition of this pump by clinically useful drugs was achieved by developing derivatives of timoprazole, pyridyl‐2‐methylsulftnyl benzimidazole. Two of these derivatives, omeprazole and lansoprazole, have shown superiority in acid control and therefore in therapy for peptic ulcer disease compared to the available H2‐receptor antagonists.