bluuebunny/crossref_metadata_2025 huggingface dataset:
Evidence for refilling of previously emptied basaltic pillows in the Hooggenoeg Complex, Barberton Greenstone Belt
Authors: ROBINS BRIAN , SANDSTÅ NILS R. , FURNES HARALD , DE WIT MAARTEN
Published: October 2010

Some large metabasaltic pillows in the uppermost part of the Palaeoarchaean Hooggenoeg Complex in the Barberton Greenstone Belt, South Africa, exhibit flow-banded margins and homogeneous cores that have a different texture and compositional variation. The margins consist of millimetre to several centimetre thick alternating bands of pale green spherulitic and darker, conspicuously variolitic varieties of non-vesicular and aphyric metabasalt, previously inferred to be due to mingling of two different types of lava. The dark cores have sharp, aphanitic contacts with the flow-banded carapaces. They lack flow banding, have coarse-grained interiors and exhibit well-preserved primary textures with pseudomorphs after prismatic pyroxene set in a groundmass containing skeletal plagioclase. The compositional range of samples from these cores is unlike that of the flow-banded metabasalt but is similar to a 19 m thick lobate metabasalt flow ~150 m stratigraphically further up, at the local top of the Hooggenoeg volcanic sequence. The pillow cores are inferred to result from the later refilling of drained hollow pillows.
Fano resonances in acoustics
Authors: HEIN STEFAN , KOCH WERNER , NANNEN LOTHAR
Published: October 2010

In contrast to completely open systems, laterally confined domains can sustain localized, truly trapped modes with nominally zero radiation loss. These discrete resonant modes cannot be excited linearly by the continuous propagating duct modes due to symmetry constraints. If the symmetry of the geometry is broken the trapped modes become highly localized quasi-trapped modes which can interfere with the propagating duct modes. The resulting narrowband Fano resonances with resonance and antiresonance features are a generic phenomenon in all scattering problems with multiple resonant pathways. This paper deals with the classical scattering of acoustic waves by various obstacles such as hard-walled single and multiple circular cylinders or rectangular and wedge-like screens in a two-dimensional duct without mean flow. The transmission and reflection coefficients as well as the (complex) resonances are computed numerically by means of the finite-element method in conjunction with two different absorbing boundary conditions, namely the complex scaling method and the Hardy space method. The results exhibit the typical asymmetric Fano line shapes near the trapped-mode resonances if the symmetry of the geometry is broken.
Outcomes of hospitalized patients with bacteraemic and non-bacteraemic community-acquired pneumonia caused by Streptococcus pneumoniae
Authors: LIN S.-H. , LAI C.-C. , TAN C.-K. , LIAO W.-H. , HSUEH P.-R.
Published: October 2010

In contrast to bacteraemic pneumococcal community-acquired pneumonia (CAP), there is a paucity of data on the clinical characteristics and outcomes of non-bacteraemic pneumococcal CAP. This retrospective study compared the outcome of hospitalized patients with bacteraemic and non-bacteraemic pneumococcal CAP treated at a medical centre from 2004 to 2008. Data on clinical outcomes including all-cause mortality, length of hospital stay, need for intensive-care unit admission and extrapulmonary involvement were analysed. In all, 221 patients with pneumococcal pneumonia (87 bacteraemic, 134 non-bacteraemic) were included. Patients with bacteraemic pneumococcal pneumonia (BPP) were older than those with non-BPP (46·2±30·7 years vs. 21·7±30·8 years, P<0·001) and were more likely to have underlying medical diseases (66·7% vs. 33·6%, P<0·001). The overall mortality rates at 7, 14, and 30 days were significantly higher in BPP than non-BPP patients (12·6% vs. 2·2%, 14·9% vs. 3·7%, 19·5% vs. 5·1%, all P<0·01). Multivariate logistic regression analysis showed that pneumococcal bacteraemia was correlated with extrapulmonary involvement (odds ratio 5·46, 95% confidence interval 1·97–15·16, P=0·001). In conclusion, S. pneumoniae bacteraemia increased the risk of mortality and extrapulmonary involvement in patients with pneumococcal CAP.
MONEY, MARKETS, AND DYNAMIC CREDIT
Authors: Sun Hongfei
Published: October 2010

This paper presents an integrated theory of money and dynamic credit. I study financial intermediation when both the intermediary and individuals have private information. I show that money is essential to solving two-sided incentive problems under the dynamic credit arrangement. First, requiring settlement with money can induce market trades that generate information-revealing prices to discipline the intermediary. Second, it is optimal for the intermediary to issue money that can record its own history of being used in settlements, and to require that settlements be made with only money that has been returned to the intermediary every settlement period. This arrangement effectively reduces individuals' incentives to deviate and allows intermediation to achieve efficient allocations.
Development and testing of stable supports for the National Synchrotron Light Source II RF beam position monitors
Authors: Kosciuk B. , Ravindranath V. , Singh O. , Sharma S.
Published: October 2010

The National Synchrotron Light Source II currently under construction at the Brookhaven National Laboratory is expected to provide unprecedented orbit stability in the storage ring in order to fully utilize the very small emittance of the electron beam. The desire to measure the position of such small beams to high resolution imposes stringent requirements on the thermal and structural stability of the supports for the beam postion monitor (BPM) pick-up electrodes located on multi-pole vacuum chambers and more so on those located upstream and downstream of insertion device sources where the beam size is the smallest. Even with tunnel air temperature expected to be controlled to ±0.1°C, low coefficient of thermal expansion materials is required to meet this level of thermal stability. Here, we present the application of these materials to the design of stable supports for radio frequency (RF)-BPMs as well as the methods of testing their performance.
Mechanical design and analysis of in-vacuum undulators at the Shanghai Synchrotron Radiation Facility
Authors: Jiang Z. , Du H. , Chen C. , Fan Y. , Wang X.
Published: October 2010

Two in-vacuum undulators (IVU25) have been used since March 2009 at the Shanghai Synchrotron Radiation Facility. Another small-gap in-vacuum undulator with a smaller period length of 20 mm was completed in July 2010. The mechanical system of IVU25 consists of support frame, driving and guiding system, taper mechanism, compensation spring system, suspending rods assembly, etc. We have attempted to manufacture IVU25 with high mechanical stability, rigidity and reproducible gap motion. A mechanical design study of IVU25 is carried out which includes finite-element calculations on the mechanical deformation of the girder. Some modifications have been made to the design of IVU20.
Stratospheric influence on the seasonal cycle of nitrous oxide in the troposphere as deduced from aircraft observations and model simulations
Authors: Ishijima Kentaro , Patra Prabir K. , Takigawa Masayuki , Machida Toshinobu , Matsueda Hidekazu , Sawa Yosuke , Steele L. Paul , Krummel Paul B. , Langenfelds Ray L. , Aoki Shuji , Nakazawa Takakiyo
Published: October 2010

The atmospheric N2O variations between the Earth's surface and the lower stratosphere, simulated by an atmospheric general circulation model–based chemistry transport model (ACTM), are compared with aircraft and satellite observations. We validate the newly developed ACTM simulations of N2O for loss rate and transport in the stratosphere using satellite observations from the Aura Microwave Limb Sounder (Aura‐MLS), with optimized surface fluxes for reproducing N2O trends observed at the surface stations. Observations in the upper troposphere/lower stratosphere (UT/LS) obtained by the Japan AirLines commercial flights commuting between Narita (36°N), Japan, and Sydney (34°S), Australia, have been used to study the role of stratosphere‐troposphere exchange (STE) on N2O variability near the tropopause. Low N2O concentration events in the UT region are shown to be captured statistically significantly by the ACTM simulation. This is attributed to successful reproduction of stratospheric air intrusion events and N2O vertical/horizontal gradients in the lower stratosphere. The meteorological fields and N2O concentrations reproduced in the ACTM are used to illustrate the mechanisms of STE and subsequent downward propagation of N2O‐depleted stratospheric air in the troposphere. Aircraft observations of N2O vertical profile over Surgut (West Siberia, Russia; 61°N), Sendai‐Fukuoka (Japan; 34°N–38°N), and Cape Grim (Tasmania, Australia; 41°S) have been used to estimate the relative contribution of surface fluxes, transport seasonality in the troposphere, and STE to N2O seasonal cycles at different altitude levels. Stratospheric N2O tracers are incorporated in the ACTM for quantitative estimation of the stratospheric influence on tropospheric N2O. The results suggest strong latitude dependency of the stratospheric contribution to the tropospheric N2O seasonal cycle. The periods of seasonal minimum in the upper troposphere, which are spring over Japan and summer over Surgut, are in good agreement between the ACTM and observation and indicate a different propagation path of the stratospheric signal between the two sites in the Northern Hemisphere. The stratospheric tracer simulations, when utilized with the observed seasonal cycle, also provide qualitative information on the seasonal variation in surface fluxes of N2O.
Grounding line migration in an adaptive mesh ice sheet model
Authors: Gladstone R. M. , Lee V. , Vieli A. , Payne A. J.
Published: October 2010

Grounding line migration is a key process affecting the stability of marine ice sheets such as the West Antarctic ice sheet. Recent studies have shown that ice sheet models employing a fixed spatial grid (such as are commonly used for whole ice sheet simulations) cannot be used to solve this problem in a robust manner. We have developed a one‐dimensional (vertically integrated) “shelfy stream” ice sheet model that employs the adaptive mesh refinement (AMR) technique to bring higher resolution to spatially and temporally evolving subregions of the model domain. A higher‐order solver, the piecewise parabolic method (PPM), is used to compute the thickness evolution. Both AMR and PPM extend readily to greater than one dimension and could be used in full ice sheet simulations. We demonstrate that this approach can bring improvements in terms of accuracy and consistency in both grounded ice sheet and ice stream/ice shelf simulations, given the appropriate choice of refinement criteria. In particular, we demonstrate that AMR, in conjunction with a parameterization for subgrid scale grounding line position, can produce predictions of grounding line migration.
Dissolved organic carbon export and internal cycling in small, headwater lakes
Authors: Stets Edward G. , Striegl Robert G. , Aiken George R.
Published: October 2010

Carbon (C) cycling in freshwater lakes is intense but poorly integrated into our current understanding of overall C transport from the land to the oceans. We quantified dissolved organic carbon export (DOCX) and compared it with modeled gross DOC mineralization (DOCR) to determine whether hydrologic or within‐lake processes dominated DOC cycling in a small headwaters watershed in Minnesota, USA. We also used DOC optical properties to gather information about DOC sources. We then compared our results to a data set of approximately 1500 lakes in the Eastern USA (Eastern Lake Survey, ELS, data set) to place our results in context of lakes more broadly. In the open‐basin lakes in our watershed (n = 5), DOCX ranged from 60 to 183 g C m−2 lake area yr−1, whereas DOCR ranged from 15 to 21 g C m−2 lake area yr−1, emphasizing that lateral DOC fluxes dominated. DOCX calculated in our study watershed clustered near the 75th percentile of open‐basin lakes in the ELS data set, suggesting that these results were not unusual. In contrast, DOCX in closed‐basin lakes (n = 2) was approximately 5 g C m−2 lake area yr−1, whereas DOCR was 37 to 42 g C m−2 lake area yr−1, suggesting that internal C cycling dominated. In the ELS data set, median DOCX was 32 and 12 g C m−2 yr−1in open‐basin and closed‐basin lakes, respectively. Although not as high as what was observed in our study watershed, DOCX is an important component of lake C flux more generally, particularly in open‐basin lakes.
A mechanism for low‐extent melts at the lithosphere‐asthenosphere boundary
Authors: Till Christy B. , Elkins‐Tanton Linda T. , Fischer Karen M.
Published: October 2010

Recent studies have imaged sharp vertical drops in shear wave velocity at the lithosphere‐asthenosphere boundary (LAB). In some regions, the magnitude of the negative velocity gradient at the LAB is too large to be explained by changes in temperature alone. This study demonstrates that small amounts of partial melt in the shallow asthenosphere are a viable model for this sharp seismic boundary. In particular, we examine melting in the upper asthenosphere at the edge of thick cratonic lithosphere, using the example of eastern North America where a sharp LAB velocity gradient has been observed. Finite element modeling of asthenospheric flow at an abrupt lateral decrease in lithosphere thickness indicates that this geometry, together with lateral plate motions, produces edge‐driven convection and asthenospheric upwelling at the continental margin. A key component of this work is a comparison of the locations and extents of melting produced by using different models for the depression of the peridotite solidus with varying H2O content. In addition, we develop a simplified parameterization of the H2O‐undersaturated peridotite solidus for a constant degree of H2O saturation in nominally anhydrous minerals. The patterns of mantle flow produced by our numerical modeling and various solidus parameterizations predict less than 0.1 wt % to 2.8 wt % (0.01–3.3 vol %) melting at depths between 102 and 126 km for an asthenosphere with a mantle potential temperature of 1350°C and 150 ppm H2O, or between 91 km and a maximum of 200 km for a mantle at 1350°C and 450 ppm H2O. If the asthenosphere has a mantle potential temperature ≤1340°C or contains less than 150 ppm H2O at 3 GPa, no melting will occur. This process of generating melt in the asthenosphere to produce a sharp vertical velocity gradient at the LAB is viable in other locations where convective upwelling occurs in the shallow asthenosphere although it is dependent on asthenospheric potential temperature, composition, and H2O content. Because the asthenosphere may be heterogeneous in composition and H2O content, the onset of melting below the LAB may fluctuate with time and space, as may the magnitude of the shear velocity drop at the LAB.
Predicting regime shifts in flow of the Colorado River
Authors: Gangopadhyay Subhrendu , McCabe Gregory J.
Published: October 2010

The effects of continued global warming on water resources are a concern for water managers and stake holders. In the western United States, where the combined climatic demand and consumptive use of water is equal to or greater than the natural supply of water for some locations, there is growing concern regarding the sustainability of future water supplies. In addition to the adverse effects of warming on water supply, another issue for water managers is accounting for, and managing, the effects of natural climatic variability, particularly persistently dry and wet periods. Analyses of paleo‐reconstructions of Upper Colorado River basin (UCRB) flow demonstrate that severe sustained droughts, and persistent pluvial periods, are a recurring characteristic of hydroclimate in the Colorado River basin. Shifts between persistently dry and wet regimes (e.g., decadal to multi‐decadal variability (D2M)) have important implications for water supply and water management. In this study paleo‐reconstructions of UCRB flow are used to compute the risks of shifts between persistently wet and dry regimes given the length of time in a specific regime. Results indicate that low frequency variability of hydro‐climatic conditions and the statistics that describe this low frequency variability can be useful to water managers by providing information about the risk of shifting from one hydrologic regime to another. To manage water resources in the future water managers will have to understand the joint hydrologic effects of natural climate variability and global warming. These joint effects may produce future hydrologic conditions that are unprecedented in both the instrumental and paleoclimatic records.
Uppermost mantle anisotropy beneath the southern Laurentian margin: Evidence from Knippa peridotite xenoliths, Texas
Authors: Satsukawa Takako , Michibayashi Katsuyoshi , Raye Urmidola , Anthony Elizabeth Y. , Pulliam Jay , Stern Robert
Published: October 2010

Peridotite xenoliths from southern Texas consist of spinel lherzolite, harzburgite and minor dunite. Based on phase relations and temperature of equilibration, Knippa xenoliths come from the uppermost mantle, 40–70 km deep. Knippa xenoliths provide rare snapshots of upper mantle processes and compositions beneath south‐central Laurentia. They preserve olivine a‐axis fiber fabrics with a strong concentration of [100] and girdles of [010] and [001]. Assuming a lithospheric mantle having a horizontal flow direction parallel to fast directions, the mantle lithospheric fabric revealed by the xenoliths mostly explains the magnitude of observed shear‐wave splitting observed along the southern margin of the Laurentian craton.
A comparison of ionospheric O+/light‐ion transition height derived from ion‐composition measurements and the topside ion density profiles over equatorial latitudes
Authors: Tulasi Ram S. , Liu C. H. , Su S.‐Y. , Heelis R. A.
Published: October 2010

A comparative investigation is made, for the first time, of direct (ion‐composition measurements) and indirect (from topside ion density profiles) methods to determine the O+/light‐ion transition height over equatorial latitudes. The transition height determined from the ion‐composition follows similar latitudinal and local time variations as the underlying Equatorial Ionization Anomaly (EIA) in the F‐region ionosphere. The north‐south hemispheric asymmetries in the transition height from ion composition are consistent with the summer‐to‐winter interhemispheric neutral wind patterns. On the other hand, the transition height derived from ion density profiles is chiefly influenced by changes in the scale height (shape) due to vertical E × B drift at the equator and steep vertical ion density gradients in topside ionosphere. As a result, the transition height derived from topside profiles are systematically lower and exhibit inconsistent latitudinal and local time variations when compared to direct ion‐composition measurements at equatorial latitudes.
Mixed layer heat budget in the Iceland Basin from Argo
Authors: de Boisséson E. , Thierry V. , Mercier H. , Caniaux G.
Published: October 2010

The mixed layer processes that govern the mode water properties in the Iceland Basin are quantified through a mixed layer heat budget from Argo data collected over 2001–2007. This budget includes the mixed layer heat content variation, the surface heat fluxes, and the Ekman contribution to advection. The geostrophic advection cannot be directly estimated from Argo data but, following previous works, an ad hoc procedure is implemented to take it into account. The resulting annual budget is closed within the error bar but this closure hides some compensation between the summer and the winter residuals (−16 ± 9 W m−2 and 21 ± 26 W m−2, respectively). A similar heat budget built by using colocated Argo floats in the 1/4° DRAKKAR ORCA025‐G70fo simulation over 2001–2007 shows seasonal patterns similar to the Argo‐based budget. An Eulerian model‐based heat budget in the Iceland Basin shows that the mixed layer heat content variation is driven by the air‐sea fluxes, the advection, and the vertical diffusion. The indirect estimate of the latter in a new Argo‐based budget leads to a summer residual of 2 ± 11 W m−2 and to an unchanged winter residual. The summer and winter standard errors of the Argo‐based budget (11 and 26 W m‐2, respectively) reflect the limited sampling of the Iceland Basin by Argo floats. Sensitivity experiments show that such errors would be reduced by a denser Argo sampling.
Geologic context of proposed chloride‐bearing materials on Mars
Authors: Osterloo Mikki M. , Anderson F. Scott , Hamilton Victoria E. , Hynek Brian M.
Published: October 2010

We use Thermal Emission Imaging System (THEMIS) data to identify and characterize the global distribution of distinct materials interpreted to contain chloride salts on the Martian surface. Previously mapped global geochemical and physical properties are used in concert with thermophysical and morphological observations to assess the materials' local and regional characteristics. The results of our survey have expanded the characterization of the materials from ∼200 to ∼640 distinct sites dispersed throughout low‐albedo Noachian‐ and Hesperian‐aged terrains. Our survey also shows that the materials are detected in locally thermophysically distinct terrains and display a range of morphologies. Topography indicates that the majority of the materials occur in local lows, although crosscutting relationships indicate that some sites are located in “geologic windows” implying that the materials may be older than the terrains in which they are situated. Once exposed, the materials appear to undergo erosion, which may be the reason we do not observe large laterally extensive materials at the surface. The materials are predominantly local in nature, yet their prevalence across the southern highlands suggests that they represent one or more globally ubiquitous processes. We consider a number of formation hypotheses but find that most observations are consistent with formation via ponding of surface runoff or groundwater upwelling, although efflorescence and hydrothermal activity may also be possible in some locales. The materials' inferred ages suggest that the conditions that enabled the deposition of the materials persisted for up to 1 billion years.
Unusual viral ligand with alternative interactions is presented by HLA‐Cw4 in human respiratory syncytial virus‐infected cells
Authors: Infantes Susana , Lorente Elena , Cragnolini Juan José , Ramos Manuel , García Ruth , Jiménez Mercedes , Iborra Salvador , Del Val Margarita , López Daniel
Published: October 2010

Short viral antigens bound to human major histocompatibility complex (HLA) class I molecules are presented on infected cells. Vaccine development frequently relies on synthetic peptides to identify optimal HLA class I ligands. However, when natural peptides are analyzed, more complex mixtures are found. By immunoproteomics analysis, we identify in this study a physiologically processed HLA ligand derived from the human respiratory syncytial virus matrix protein that is very different from what was expected from studies with synthetic peptides. This natural HLA‐Cw4 class I ligand uses alternative interactions to the anchor motifs previously described for its presenting HLA‐Cw4 class I molecule. Finally, this octameric peptide shares its C‐terminal core with the H‐2Db nonamer ligand previously identified in the mouse model. These data have implications for the identification of antiviral cytotoxic T lymphocyte responses and for vaccine development.
Modeling miRNA regulation in signaling networks: miR-34a regulation of the p53/Sirt1 module
Authors: Lai Xin
Published: October 2010

Micro RNAs are a family of small regulatory RNAs whose function is to regulate the activity and stability of specific messenger RNA targets through post-translational regulatory mechanisms. We studied a signaling module composed by p53, Sirt1 and the small regulatory miRNA, miR-34a, based on the integration of experimental evidence and quantitative data, with mathematical modeling. We further used the model to investigate different possible designs of the silencing mechanisms exerted by miR-34a on Sirt1, and to simulate the dynamics of the system under pathological conditions of deregulation of its components.
BioModels Database: Next generation model repository
Authors: Laibe Camille , Hoehl Michael
Published: October 2010

Public announce that the software system running BioModels Database ("http://www.ebi.ac.uk/biomodels/":http://www.ebi.ac.uk/biomodels/) will evolve from open source to a community developed project.
Cell surface heparan sulfates mediate internalization of the PWWP/HATH domain of HDGF via macropinocytosis to fine-tune cell signalling processes involved in fibroblast cell migration
Authors: Wang Chia-Hui , Davamani Fabian , Sue Shih-Che , Lee Shao-Chen , Wu Po-long , Tang Fan-Mei , Shih Chiaho , Huang Tai-huang , Wu Wen-guey
Published: October 2010

HDGF (hepatoma-derived growth factor) stimulates cell proliferation by functioning on both sides of the plasma membrane as a ligand for membrane receptor binding to trigger cell signalling and as a stimulator for DNA synthesis in the nucleus. Although HDGF was initially identified as a secretory heparin-binding protein, the biological significance of its heparin-binding ability remains to be determined. In the present study we demonstrate that cells devoid of surface HS (heparan sulfate) were unable to internalize HDGF, HATH (N-terminal domain of HDGF consisting of amino acid residues 1–100, including the PWWP motif) and HATH(K96A) (single-site mutant form of HATH devoid of receptor binding activity), suggesting that the binding of HATH to surface HS is important for HDGF internalization. We further demonstrate that both HATH and HATH(K96A) could be internalized through macropinocytosis after binding to the cell surface HS. Interestingly, HS-mediated HATH(K96A) internalization is found to exhibit an inhibitory effect on cell migration and proliferation in contrast with that observed for HATH action on NIH 3T3 cells, suggesting that HDGF exploits the innate properties of both cell surface HS and membrane receptor via the HATH domain to affect related cell signalling processes. The present study indicates that MAPK (mitogen-activated protein kinase) signalling pathways could be affected by the HS-mediated HATH internalization to regulate cell migration in NIH 3T3 fibroblasts, as judged from the differential effect of HATH and HATH(K96A) treatment on the expression level of matrix metalloproteases.
Specific amino acids in the BAR domain allow homodimerization and prevent heterodimerization of sorting nexin 33
Authors: Dislich Bastian , Than Manuel E. , Lichtenthaler Stefan F.
Published: October 2010

SNX33 (sorting nexin 33) is a homologue of the endocytic prote-in SNX9 and has been implicated in actin polymerization and the endocytosis of the amyloid precursor protein. SNX33 belongs to the large family of BAR (Bin/amphiphysin/Rvs) domain-containing proteins, which alter cellular protein trafficking by modulating cellular membranes and the cytoskeleton. Some BAR domains engage in homodimerization, whereas other BAR domains also mediate heterodimerization between different BAR domain-containing proteins. The molecular basis for this difference is not yet understood. Using co-immunoprecipitations we report that SNX33 forms homodimers, but not heterodimers, with other BAR domain-containing proteins, such as SNX9. Domain deletion analysis revealed that the BAR domain, but not the SH3 (Src homology 3) domain, was required for homodimerization of SNX33. Additionally, the BAR domain prevented the heterodimerization between SNX9 and SNX33, as determined by domain swap experiments. Molecular modelling of the SNX33 BAR domain structure revealed that key amino acids located at the BAR domain dimer interface of the SNX9 homodimer are not conserved in SNX33. Replacing these amino acids in SNX9 with the corresponding amino acids of SNX33 allowed the mutant SNX9 to heterodimerize with SNX33. Taken together, the present study identifies critical amino acids within the BAR domains of SNX9 and SNX33 as determinants for the specificity of BAR domain-mediated interactions and suggests that SNX9 and SNX33 have distinct molecular functions.
Intramammary Infusion ofβ1,3‐glucan for Prevention and Treatment ofStaphylococcus aureusMastitis
Authors: Persson Waller K. , Grönlund U. , Johannisson A
Published: October 2010

Udder health problems associated withStaphylococcus aureusinfections in dairy cows are difficult to control and antibiotics have limited effects. Lately, more interest has been directed towards ways to stimulate the innate immune mechanisms of the animal for better prevention and treatment of mastitis. The objectives of this study were to investigate if intramammary infusion at drying off with the immune modulatorβ1,3‐glucan can make the udder more resistant to experimental intra mammaryS. aureusinfection at this time, and to study if intramammary infusion ofβ1,3‐glucan into lactating udder quarters with chronic subclinicalS. aureusinfection can stimulate the clearing of the infection. Another aim was to evaluate the effect ofβ1,3‐glucan on the expression of major histocompatibility complex (MHC class II) on mammary leucocytes, measured by flow cytometry, during these circumstances. The results indicated a slight, but not statistically significant, positive effect ofβ1,3‐glucan at drying off on the clinical and anti‐bacterial response toS. aureusinfection, but no therapeutic effect ofβ1,3‐glucan treatment of udder quarters with chronic subclinicalS. aureusmastitis. However, the proportion of MHCII+ milk lymphocytes tended to increase after glucan infusion in those udder quarters indicating a stimulation of the antigen presenting ability. To further evaluate a possible preventive effect ofβ1,3‐glucan infusion at drying off more studies are needed involving a larger number of animals.
Detection of Chlamydophila abortus in Ovine Milk by Immunomagnetic Separation–Polymerase Chain Reaction
Authors: Öngör H. , Çetinkaya B. , Açik M. N. , Karahan M. , Bulut H.
Published: October 2010

The present study was carried out to investigate the presence of Chlamydophila abortus, the causative agent of ovine enzootic abortion, in milk samples collected from sheep flocks with and without the history of abortion in Eastern Turkey by means of immunomagnetic separation (IMS) in conjunction with the polymerase chain reaction (PCR). A total number of 201 milk samples collected from 10 flocks with abortion and four flocks without abortion were tested. In the analysis of the milk samples by IMS–PCR, correct amplification was obtained with three (1.5%) samples originating from one flock with abortion. In the digestion of PCR positive products by AluI, restriction profiles observed in all three samples were determined to be the same as C. abortus S26/3.
Identification of Yersinia enterocolitica in Minced Meat: A Comparative Analysis of API 20E, Yersinia Identification Kit and a 16S rRNA‐based PCR Method
Authors: Arnold T. , Neubauer H. , Nikolaou K. , Roesler U. , Hensel A.
Published: October 2010

The isolation and identification of Yersinia enterocolitica from minced meat on CIN agar medium is still one of the major problems in food microbiology because of the low selectivity of cefsulodin–irgasan–novobiocin (CIN) agar. A total of 198 minced meat samples were collected from commercial establishments (butcher shops and supermarkets) in seven German cities in order to investigate the sensitivity and specificity of three identification techniques suitable for the differentiation of Y. enterocolitica within the rich background flora on CIN agar plates. As expected isolation of Y. enterocolitica from minced meat on CIN agar medium after 72 h enrichment in peptone, sorbitol and bile salts (PSB) broth was difficult because all plates were abundantly covered with numerous ‘typical’Yersinia‐like colonies of bull's eye appearance as well as with atypical colonies. Based on the phenotype of the colonies it was possible to detect colonies showing Yersinia‐like growth on CIN agar in 52 samples (26%). For identification of Y. enterocolitica the API 20E system (bioMerieux, Nürtingen, Germany), the Yersinia identification kit (Merlin, Bornheim‐Hersel, Germany) and a 16S rRNA based PCR assay were compared. Only in one sample (0.5%) a Y. enterocolitica strain was detected by all methods. Of the three identification systems tested for routine laboratory diagnostics the API 20E system was found to be the most suitable tool to identify Y. enterocolitica colonies within the rich background flora from minced meat samples on CIN agar plates.
The pot snack market – are today's consumers demanding health as well as convenience?
Authors: McCullough Fiona , Jones Sian , Vignali Daniella
Published: October 2010

Identifying the target audience for hot pot snacks and which factors influence their buyer behaviour is vital information for product developers and manufacturers. The reported market research evaluated the effect of changing lifestyles on the growth of the pot snack market and investigated consumer opinion of pot snacks with particular regard to their nutritional status. This information is of particular interest to health professionals involved in improving the nation's health.

A consumer questionnaire measured the opinion of pot snacks, frequency of consumption and influences on the growth of the pot snack market. The 150 consumers comprised   86   males   and 64   females   aged   11–74 years.   The data was analysed using chi‐square (Statistical Package for Social   Sciences).   Results indicated   that   within   the   pot snack market, there are a variety of reasons determining the demand for pot snacks. The frequency of consumption is influenced by knowledge and opinion about the nutritional content of the pot snack product, suggest‐ing that consumers are now demanding health as well as convenience.
Microinjection of Guanine NucleotideAnalogues into Lily Pollen Tubes Results in Isodiametric TipExpansion
Authors: Eliáŝ M. , Cvrĉková F. , Obermeyer G. , Žársky V.
Published: October 2010

Abstract: Heterotrimeric and small G‐proteins aresupposed to participate in tip growth of plant cells. Quantitative changes intip growth rate after introduction of non‐hydrolysable guanine nucleotideanalogues (NA) into lily pollen tubes have been interpreted as support for thehypothesis that heterotrimeric G‐proteins regulate tube elongation (Ma et al.,1999 IDREF=“R243‐11”>11). Here, we report that microinjection of guanineNA into lily pollen tubes causes loss of growth polarity, resulting inisodiametric tip swelling. Our results are compatible with current modelssuggesting an involvement of plant Rho‐related small G‐proteins (Rop) in themaintenance of pollen tube polarity and in tip morphogenesis.
Characterization of juvenile and adult leaves of Eucalyptus globulus showing distinct heteroblastic development: photosynthesis and volatile isoprenoids
Authors: Velikova V. , Loreto F. , Brilli F. , Stefanov D. , Yordanov I.
Published: October 2010

Heteroblastic Eucalyptus (Eucalyptus globulus L.) leaves were characterized for their functional diversity examining photosynthesis and photosynthesis limitations, transpiration, and the emission of isoprene and monoterpenes. In vivo and combined analyses of gas‐exchange, chlorophyll fluorescence, and light absorbance at 830 nm were made on the adaxial and abaxial sides of juvenile and adult leaves. When adult leaves were reversed to illuminate the abaxial side, photosynthesis and isoprene emission were significantly lower than when the adaxial side was illuminated. Monoterpene emission, however, was independent on the side illuminated and similarly partitioned between the two leaf sides. The abaxial side of adult leaves showed less diffusive resistance to CO2 acquisition by chloroplasts, but also lower ribulose‐1,5‐bisphosphate carboxylase/oxygenase (Rubisco) activity, than the adaxial leaf side. In juvenile leaves, photosynthesis, isoprene, and monoterpene emissions were similar when the adaxial or abaxial side was directly illuminated. In the abaxial side of juvenile leaves, photosynthesis did not match the rates attained by the other leaf types when exposed to elevated CO2, which suggests the occurrence of a limitation of photosynthesis by ribulose bisphosphate (RuBP) regeneration. Accordingly, a reduced efficiency of both photosystems and a high non‐radiative dissipation of energy was observed in the abaxial side of juvenile leaves. During light induction, the adaxial side of juvenile leaves also showed a reduced efficiency of photosystem II and a large non‐radiative energy dissipation. Our report reveals distinct functional properties in Eucalyptus leaves. Juvenile leaves invest more carbon in isoprene, but not in monoterpenes, and have a lower water use efficiency than adult leaves. Under steady‐state conditions, in adult leaves the isobilateral anatomy does not correspond to an equal functionality of the two sides, while in juvenile leaves the dorsiventral anatomy does not result in functional differences in primary or secondary metabolism in the two sides. However, photochemical limitations may reduce the efficiency of carbon fixation in the light, especially in the abaxial side of juvenile leaves.
Effects of species composition, land surface cover, CO2 concentration and climate on isoprene emissions from European forests
Authors: Arneth A. , Schurgers G. , Hickler T. , Miller P. A.
Published: October 2010

Emissions of isoprene from terrestrial vegetation are known to affect atmospheric chemical properties, like its oxidation capacity or the concentration of tropospheric ozone. The latter is of concern, since besides being a potent greenhouse gas, O3 is toxic for humans, animals, and plants even at relatively low concentrations. Isoprene‐emitting forests in the vicinity of NOx pollution sources (like cities) can contribute considerably to O3 formation, and to the peak concentrations observed during hot summer weather. The biogenic contribution to O3 concentrations is generally thought to increase in a future, warmer climate – pushing values beyond health thresholds possibly even more frequently and over larger areas – given that emissions of isoprene are highly temperature‐dependent but also because of the CO2 fertilisation of forest productivity and leaf growth. Most projections of future emissions, however, do not include the possible CO2‐inhibition of leaf isoprene metabolism. We explore the regional distribution of emissions from European woody vegetation, using a mechanistic isoprene‐dynamic vegetation model framework. We investigate the interactive effects of climate and CO2 concentration on forest productivity, species composition, and isoprene emissions for the periods 1981–2000 and 2081–2100. Our projection of future emissions includes a direct CO2‐isoprene inhibition. Across the model domain, we show that this direct effect has the potential to offset the stimulation of emissions that could be expected from warmer temperatures and from the increased productivity and leaf area of emitting vegetation. Changes in forest species composition that may result from climate change can play a substantial additional role in a region’s future emissions. Changes in forest area or area planted in woody biofuels in general are not noticeable in the overall European forest isoprene budget, but – as was the case for changes in species composition – may substantially affect future projections in some regions of the continent.
Isoprene emission and primary metabolism in Phragmites australis grown under different phosphorus levels
Authors: Fares S. , Brilli F. , Noguès I. , Velikova V. , Tsonev T. , Dagli S. , Loreto F.
Published: October 2010

Aquatic plants are generally used for wastewater purification and phytoremediation, but some of them also emit large amounts of isoprene, the most abundant biogenic volatile organic compound. Since isoprenoid biosynthesis requires high amounts of phosphorylated intermediates, the emission may also be controlled by inorganic phosphorus concentration (Pi) in leaves. We carried out experiments to determine the emission of isoprene from Phragmites australis plants used in reconstructed wetlands to phytoremediate elevated levels of phosphorus contributed by urban wastes. Four groups of plants were grown hydroponically in water containing different levels of KH2PO4. High levels of phosphorus in the water resulted in high Pi in the leaves. High Pi stimulated photosynthesis at intercellular CO2 concentrations lower and higher than ambient, implying higher ribulose 1,5‐bisphosphate carboxylase (Rubisco) activity and higher ribulose 1,5‐bisphosphate regeneration rates, respectively. However, isoprene emission was substantially lower at high Pi than at low Pi, and was not associated to photosynthesis rates at high Pi. This surprising result suggests that isoprene is limited by processes other than photosynthetic intermediate availability or by energetic (ATP) requirements under high Pi levels. Irrespective of the mechanism responsible for the observed reduction of isoprene emission, our results show that Phragmites plants may effectively remove phosphorus from water without concurrently increase isoprene emission, at least on a leaf area basis. Thus, Phragmites used in reconstructed wetlands for phytoremediation of urban wastes rich of phosphates will not contribute high loads of hydrocarbons which may influence air quality over urban and peri‐urban areas.
Pulse-dilation enhanced gated optical imager with 5 ps resolution (invited)
Authors: Hilsabeck T. J. , Hares J. D. , Kilkenny J. D. , Bell P. M. , Dymoke-Bradshaw A. K. L. , Koch J. A. , Celliers P. M. , Bradley D. K. , McCarville T. , Pivovaroff M. , Soufli R. , Bionta R.
Published: October 2010

A 5 ps gated framing camera was demonstrated using the pulse-dilation of a drifting electron signal. The pulse-dilation is achieved by accelerating a photoelectron derived information pulse with a time varying potential [R. D. Prosser, J. Phys. E 9, 57 (1976)]. The temporal dependence of the accelerating potential causes a birth time dependent axial velocity dispersion that spreads the pulse as it transits a drift region. The expanded pulse is then imaged with a conventional gated microchannel plate based framing camera and the effective gating time of the combined instrument is reduced over that of the framing camera alone. In the drift region, electron image defocusing in the transverse or image plane is prevented with a large axial magnetic field. Details of the unique issues associated with rf excited photocathodes were investigated numerically and a prototype instrument based on this principle was recently constructed. Temporal resolution of the instrument was measured with a frequency tripled femtosecond laser operating at 266 nm. The system demonstrated 20× temporal magnification and the results are presented here. X-ray image formation strategies and photometric calculations for inertial confinement fusion implosion experiments are also examined.
NSTX far infrared tangential interferometer/polarimeter electronics upgrade
Authors: Tsai W. C. , Domier C. W. , Lee K. C. , Luhmann N. C. , Kaita R. , Park H. K.
Published: October 2010

New electronics for the multichannel far infrared tangential interferometer/polarimeter system employed on the National Spherical Torus Experiment (NSTX) have greatly extended its capability to monitor high frequency density fluctuations. Such measurements are essential in understanding transport physics issues in NSTX as well as for the coming ITER device. The electronics, which were previously limited to ∼250 kHz, have been upgraded with a video bandwidth that extends to 4 MHz when operating as an interferometry-only configuration, and to ∼500 kHz when operating as a simultaneous interferometer/polarimeter system. Experimental details and test results of the new electronics are presented.
Collisional quenching of OD AΣ2+ by H2: Experimental and theoretical studies of the state-resolved OD XΠ2 product distribution and branching fraction
Authors: Lehman Julia H. , Dempsey Logan P. , Lester Marsha I. , Fu Bina , Kamarchik Eugene , Bowman Joel M.
Published: October 2010

We report joint experimental and theoretical studies of outcomes resulting from the nonreactive quenching of electronically excited OD A Σ2+ by H2. The experiments utilize a pump-probe technique to detect the OD X Π2 product state distribution under single collision conditions. The OD X Π2 products are observed primarily in their lowest vibrational state (v″=0) with substantially less population in v″=1. The OD X Π2 products are generated with a high degree of rotational excitation, peaking at N″=21 with an average rotational energy of 4600 cm−1, and a strong propensity for populating the Π(A′) Λ-doublet component indicative of alignment of the half-filled pπ orbital in the plane of OD rotation. Branching fraction measurements show that the nonreactive channel accounts for less than 20% of quenching outcomes. Complementary classical trajectory calculations of the postquenching dynamics are initiated from representative points along seams of conical intersections between the ground and excited-state potentials of OD(A Σ2+,X Π2)+H2. Diabatic modeling of the initial momenta in the dynamical calculations captures the key experimental trends: OD X Π2 products released primarily in their ground vibrational state with extensive rotational excitation and a branching ratio that strongly favors reactive quenching. The OD A Σ2++H2 results are also compared with previous studies on the quenching of OH A Σ2++H2; the two experimental studies show remarkably similar rotational energy distributions for the OH and OD X Π2 radical products.
Quasiclassical trajectory study of the postquenching dynamics of OH AΣ2+ by H2/D2 on a global potential energy surface
Authors: Fu Bina , Kamarchik Eugene , Bowman Joel M.
Published: October 2010

We report full-dimensional, electronically adiabatic potential energy surfaces (PESs) for the ground state (1A′) and excited state (2A′) of OH3. The PESs are permutationally invariant fits to roughly 23 000 electronic energies (MRCI+Q/aVTZ). Classical trajectory calculations of the postquenching dynamics of OH A Σ2+ are carried out on the 1A′ PES for H2 and D2, at previously identified conical intersections (CoIs) [B. C. Hoffman and D. R. Yarkony, J. Chem. Phys. 113, 10091 (2000)]. The initial momenta are sampled fully and partially microcanonically, corresponding to “adiabatic” and “diabatic” models of the dynamics, respectively. Branching ratios of reactive to nonreactive channels from separate C2v, C∞v, and Cs symmetries of CoIs are calculated, as are final rovibrational state distributions of OH and H2 products. The rovibrational distributions of the OH and D2 products, the D/H-atom translational energy distribution are calculated and compared to experimental ones. Agreement for these observable quantities is good. The branching between reactive and nonreactive quenching is sensitive to the momenta sampling; very good agreement with experiment is obtained using the diabatic sampling but not with the adiabatic sampling. The vibrational state distributions of H2O and HOD (although not measured by experiment) are also presented.
Method for cooling nanostructures to microkelvin temperatures
Authors: Clark A. C. , Schwarzwälder K. K. , Bandi T. , Maradan D. , Zumbühl D. M.
Published: October 2010

We propose a new scheme aimed at cooling nanostructures to microkelvin temperature based on the well established technique of adiabatic nuclear demagnetization: we attach each device measurement lead to an individual nuclear refrigerator, allowing efficient thermal contact to a microkelvin bath. On a prototype consisting of a parallel network of nuclear refrigerators, temperatures of ∼1 mK simultaneously on ten measurement leads have been reached upon demagnetization, thus completing the first steps toward ultracold nanostructures.