bluuebunny/crossref_metadata_2025 huggingface dataset:
Stromal Expression of CD10 in Invasive Breast Carcinoma and Its Correlation with ER, PR, HER2-neu, and Ki67
Authors: Puri Vandana , Jain Manjula , Thomas Shaji
Published: June 2011

CD10 is a cell surface zinc-dependent endopeptidase, which degrades many bioactive peptides. CD10 expression in tumour stroma is associated with biological aggressiveness of many epithelial malignancies.To date, only one study has correlated with expression of CD10 with well-known prognostic markers of breast, that is, ER, PR, HER2-neu, and tumour grade; however, its correlation with ki67 is still not studied. The aim of this study is to evaluate stromal CD10 expression in breast carcinoma and to examine its correlation with ER, PR, HER2-neu, and Ki67.Methods and Results. CD10 expression in fifty patients was assessed by immunohistochemistry and scored as negative, weak and strong. CD10 was found to be positive in stroma of 40/50 (80%) cases. Stromal CD10 showed positive correlation with tumour grade, HER2-neu (P=.000), and ki67 (P=.027), negative correlation with ER and PR.Conclusions. Hence CD10 expression correlated strongly with well-established negative prognostic markers, that is, HER2-neu and ki67 positivity, ER/PR negativity, and higher tumour grade, thus indicating that CD10 can be used as independent marker indicating poor prognosis and can be used as target for the development of novel therapies.
Hypoxia-Inducible Factor in Thyroid Carcinoma
Authors: Burrows Natalie , Babur Muhammad , Resch Julia , Williams Kaye J. , Brabant Georg
Published: June 2011

Intratumoural hypoxia (low oxygen tension) is associated with aggressive disease and poor prognosis. Hypoxia-inducible factor-1 is a transcription factor activated by hypoxia that regulates the expression of genes that promote tumour cell survival, progression, metastasis, and resistance to chemo/radiotherapy. In addition to hypoxia, HIF-1 can be activated by growth factor-signalling pathways such as the mitogen-activated protein kinases- (MAPK-) and phosphatidylinositol-3-OH kinases- (PI3K-) signalling cascades. Mutations in these pathways are common in thyroid carcinoma and lead to enhanced HIF-1 expression and activity. Here, we summarise current data that highlights the potential role of both hypoxia and MAPK/PI3K-induced HIF-1 signalling in thyroid carcinoma progression, metastatic characteristics, and the potential role of HIF-1 in thyroid carcinoma response to radiotherapy. Direct or indirect targeting of HIF-1 using an MAPK or PI3K inhibitor in combination with radiotherapy may be a new potential therapeutic target to improve the therapeutic response of thyroid carcinoma to radiotherapy and reduce metastatic burden.
Influence of histocompatibility genes on disease susceptibility and treatment response in patients with relapsing–remitting multiple sclerosis treated with interferon beta-1a
Authors: Flechter Shlomo , Klein Tirza , Pollak Lea
Published: June 2011

Multiple sclerosis (MS) is the most common, non-traumatic cause of neurological disability in young adults. The aim of this study was to investigate the influence of HLA class II alleles DRB1* and DQB1* on susceptibility to relapsing–remitting (RR) MS and response to interferon (IFN) beta-1a treatment. A prospective observational study was conducted. Seventeen patients with clinically definite RRMS, attending a tertiary referral center for multiple sclerosis in Israel and receiving treatment with subcutaneous IFN beta-1a, 22 mcg three times weekly were recruited between December 1998 and February 2000 and observed for 12 months. HLA genotyping was performed and clinical characteristics (relapse rate and disability progression) assessed at baseline and after 12 months. HLA data for a healthy control group were also used for comparison. HLA and the success of treatment with IFN beta-1a in this group of RRMS patients were assessed. The frequency of DRB1*03 was six times higher in patients treated with IFN beta-1a than in the healthy control group (n = 100): 29% (5/17) versus 5% (5/100), respectively. Additionally, DQB1*03 and DQB1*02 were present in 82% (14/17) and 41% (7/17) of RRMS patients, but in only 33% (33/100) and 18% (18/100) of control patients, respectively. A better response to IFN beta-1a treatment was seen in patients carrying these alleles than in patients without these alleles. Our results indicated that DRB1*03, DQB1*03 and DQB1*02 alleles may contribute to MS susceptibility and IFN beta-1a responsiveness, and warrant further verification in a larger population.
An analysis of cloud overlap at a midlatitude atmospheric observation facility
Authors: Oreopoulos L. , Norris P. M.
Published: June 2011

Abstract. An analysis of cloud overlap based on high temporal and vertical resolution retrievals of cloud condensate from a suite of ground instruments is performed at a mid-latitude atmospheric observation facility. Two facets of overlap are investigated: cloud fraction overlap, expressed in terms of a parameter "α" indicating the relative contributions of maximum and random overlap, and overlap of horizontal distributions of condensate, expressed in terms of the correlation coefficient of condensate ranks. The degree of proximity to the random and maximum overlap assumptions is also expressed in terms of a decorrelation length, a convenient scalar parameter for overlap parameters assumed to decay exponentially with separation distance. Both cloud fraction overlap and condensate overlap show significant seasonal variations with a clear tendency for more maximum overlap in the summer months. More maximum overlap is also generally observed when the domain size used to define cloud fractions increases. These tendencies also exist for rank correlations, but are significantly weaker. Hitherto unexplored overlap parameter dependencies are investigated by analyzing mean parameter differences at fixed separation distance within different layers of the atmospheric column, and by searching for possible systematic relationships between alpha and rank correlation. We find that for the same separation distance the overlap parameters are significantly distinct in different atmospheric layers, and that random cloud fraction overlap is usually associated with more randomly overlapped condensate ranks.
Particle concentration and flux dynamics in the atmospheric boundary layer as the indicator of formation mechanism
Authors: Lauros J. , Sogachev A. , Smolander S. , Vuollekoski H. , Sihto S.-L. , Mammarella I. , Laakso L. , Rannik Ü. , Boy M.
Published: June 2011

Abstract. We carried out column model simulations to study particle fluxes and deposition and to evaluate different particle formation mechanisms at a boreal forest site in Finland. We show that kinetic nucleation of sulphuric acid cannot be responsible for new particle formation alone as the simulated vertical profile of particle number concentration does not correspond to observations. Instead organic induced nucleation leads to good agreement confirming the relevance of the aerosol formation mechanism including organic compounds emitted by the biosphere. The simulation of aerosol concentration within the atmospheric boundary layer during nucleation event days shows a highly dynamical picture, where particle formation is coupled with chemistry and turbulent transport. We have demonstrated the suitability of our turbulent mixing scheme in reproducing the most important characteristics of particle dynamics within the boundary layer. Deposition and particle flux simulations show that deposition affects noticeably only the smallest particles in the lowest part of the atmospheric boundary layer.
Formation of hydroxyl radical from San Joaquin Valley particles extracted in a cell-free solution
Authors: Shen H. , Anastasio C.
Published: June 2011

Abstract. Previous studies have suggested that the adverse health effects from ambient particulate matter (PM) are linked to the formation of reactive oxygen species (ROS) by PM. While hydroxyl radical (•OH) is the most reactive of the ROS species, there are few quantitative studies of •OH generation from PM. Here we report on •OH formation from PM collected at an urban (Fresno) and rural (Westside) site in the San Joaquin Valley (SJV) of California. We quantified •OH in PM extracts using a cell-free, phosphate-buffered saline (PBS) solution with or without 50 μM ascorbate (Asc). The results show that generally the urban Fresno PM generates much more •OH than the rural Westside PM. The presence of Asc at a physiologically relevant concentration in the extraction solution greatly enhances •OH formation from all the samples. Fine PM (PM2.5) generally makes more •OH than the corresponding coarse PM (PMcf, i.e., 2.5 to 10 μm) normalized by air volume collected, while the coarse PM typically generates more •OH normalized by PM mass. •OH production by SJV PM is reduced on average by (97 ± 6) % when the transition metal chelator desferoxamine (DSF) is added to the extraction solution, indicating a dominant role of transition metals. By measuring calibration curves of •OH generation from copper and iron, and quantifying copper and iron concentrations in our particle extracts, we find that PBS-soluble copper is primarily responsible for •OH production by the SJV PM, while iron often makes a significant contribution. Extrapolating our results to expected burdens of PM-derived •OH in human lung lining fluid suggests that typical daily PM exposures in the San Joaquin Valley are unlikely to result in a high amount of pulmonary •OH, although high PM events could produce much higher levels of •OH, which might lead to cytotoxicity.
Space and ground segment performance and lessons learned of the FORMOSAT-3/COSMIC mission: four years in orbit
Authors: Fong C.-J. , Whiteley D. , Yang E. , Cook K. , Chu V. , Schreiner B. , Ector D. , Wilczynski P. , Liu T.-Y. , Yen N.
Published: June 2011

Abstract. The FORMOSAT-3/COSMIC (Constellation Observing System for Meteorology, Ionosphere, and Climate) Mission consisting of six Low-Earth-Orbit (LEO) satellites is the world's first demonstration constellation using radio occultation signals from Global Positioning System (GPS) satellites. The atmospheric profiles derived by processing radio occultation signals are retrieved in near real-time for global weather/climate monitoring, numerical weather prediction, and space weather research. The mission has processed, on average, 1400 to 1800 high-quality atmospheric sounding profiles per day. The atmospheric radio occultation data are assimilated into operational numerical weather prediction models for global weather prediction, including typhoon/hurricane/cyclone forecasts. The radio occultation data has shown a positive impact on weather predictions at many national weather forecast centers. A follow-on mission was proposed that transitions the current experimental research mission into a significantly improved real-time operational mission, which will reliably provide 8000 radio occultation soundings per day. The follow-on mission, as planned, will consist of 12 LEO satellites (compared to 6 satellites for the current mission) with data latency requirement of 45 min (compared to 3 h for the current mission), which will provide greatly enhanced opportunities for operational forecasts and scientific research. This paper will address the FORMOSAT-3/COSMIC system and mission overview, the spacecraft and ground system performance after four years in orbit, the lessons learned from the encountered technical challenges and observations, and the expected design improvements for the spacecraft and ground system for FORMOSAT-7/COSMIC-2.
Sources of short-lived bromocarbons in the Iberian upwelling system
Authors: Raimund S. , Quack B. , Bozec Y. , Vernet M. , Rossi V. , Garçon V. , Morel Y. , Morin P.
Published: June 2011

Abstract. Seawater concentrations of the four brominated trace gases, dibromomethane (CH2Br2), bromodichloromethane (CHBrCl2), dibromochloromethane (CHBr2Cl) and bromoform (CHBr3) were measured at different depths of the water column in the Iberian upwelling off Portugal during summer 2007. Statistical analysis of the data set revealed three distinct clusters, caused by different sea surface temperature. Bromocarbon concentrations were elevated in recently upwelled and aged upwelled waters (mean values of 30 pmol l−1 for CHBr3), while concentrations in the open ocean were significantly lower (7.4 pmol l−1 for CHBr3). Comparison with other productive marine areas revealed that the Iberian upwelling had higher halocarbon concentrations than the Mauritanian upwelling. However, the concentrations off the Iberian Peninsula were still much lower than those of coastal macroalgal-influenced waters or those of Polar regions dominated by cold water adapted diatoms. Correlations with biological variables and marker pigments indicated that phytoplankton was a source of bromocarbon in the open ocean. By contrast, in upwelled water masses along the coast, halocarbons showed weaker correlations to marker pigments but were significantly influenced by the tidal frequency. Our results indicate a strong intertidal coastal source of bromocarbon and transport by surface currents of these enriched waters towards the upwelling region.
The early Eocene equable climate problem revisited
Authors: Huber M. , Caballero R.
Published: June 2011

Abstract. The early Eocene "equable climate problem", i.e. warm extratropical annual mean and above-freezing winter temperatures evidenced by proxy records, has remained as one of the great unsolved problems in paleoclimate. Recent progress in modeling and in paleoclimate proxy development provides an opportunity to revisit this problem to ascertain if the current generation of models can reproduce the past climate features without extensive modification. Here we have compiled early Eocene terrestrial temperature data and compared with climate model results using a consistent and rigorous methodology. We test the hypothesis that equable climates can be explained simply as a response to increased greenhouse gas forcing within the framework of the atmospheric component of the Community Climate System Model (version 3), a climate model in common use for predicting future climate change. We find that, with suitably large radiative forcing, the model and data are in general agreement for annual mean and cold month mean temperatures, and that the pattern of high latitude amplification recorded by proxies can be largely, but not perfectly, reproduced.
Methane variations on orbital timescales: a transient modeling experiment
Authors: Konijnendijk T. Y. M. , Weber S. L. , Tuenter E. , van Weele M.
Published: June 2011

Abstract. Methane (CH4) variations on orbital timescales are often associated with variations in wetland coverage, most notably in the summer monsoon areas of the Northern Hemisphere. Here we test this assumption by simulating orbitally forced variations in global wetland emissions, using a simple wetland distribution and CH4 emissions model that has been run on the output of a climate model (CLIMBER-2) containing atmosphere, ocean and vegetation components. The transient climate modeling simulation extends over the last 650 000 yr and includes variations in land-ice distribution and greenhouse gases. Tropical temperature and global vegetation are found to be the dominant controls for global CH4 emissions and therefore atmospheric concentrations. The relative importance of wetland coverage, vegetation coverage, and emission temperatures depends on the specific climatic zone (boreal, tropics and Indian/Asian monsoon area) and timescale (precession, obliquity and glacial-interglacial timescales). Despite the low spatial resolution of the climate model and crude parameterizations for methane production and release, simulated variations in CH4 emissions agree well with those in measured concentrations, both in their time series and spectra. The simulated lags between emissions and orbital forcing also show close agreement with those found in measured data, both on the precession and obliquity timescale. We find causal links between atmospheric CH4 concentrations and tropical temperatures and global vegetation, but only covariance between monsoon precipitation and CH4 concentrations. The primary importance of the first two factors explains the lags found in the CH4 record from ice cores. Simulation of the dynamical vegetation response to climate variation on orbital timescales would be needed to reduce the uncertainty in these preliminary attributions.
The Middle Miocene climate as modelled in an atmosphere-ocean-biosphere model
Authors: Krapp M. , Jungclaus J. H.
Published: June 2011

Abstract. We present simulations with a coupled ocean-atmosphere-biosphere model for the Middle Miocene 15 million years ago. The Middle Miocene topography, which alters both large-scale ocean and atmospheric circulations, causes a global warming of 0.7 K compared to present-day. Higher than present-day CO2 levels of 480 and 720 ppm cause a global warming of 2.8 and 4.9 K, thereby matching proxy-based Middle Miocene global temperature estimates of 3–6 K warming. Higher CO2 levels and the associated water vapour feedback enhance the greenhouse effect and lead to a polar amplification of the warming. Although oceanic and atmospheric poleward heat transport are individually altered by 10–30 % in the mid and high latitudes, changes of the total heat transport account only for 4–8 %, pointing toward a compensation between oceanic and atmospheric heat transport. Our model reproduces a denser vegetation in agreement with fossil records. These results suggest that higher than present-day CO2 levels are essential to drive the warm Middle Miocene climate.
Differences and implications in biogeochemistry from maximizing entropy production locally versus globally
Authors: Vallino J. J.
Published: June 2011

Abstract. In this manuscript we investigate the use of the maximum entropy production (MEP) principle for modeling biogeochemical processes that are catalyzed by living systems. Because of novelties introduced by the MEP approach, many questions need to be answered and techniques developed in the application of MEP to describe biological systems that are responsible for energy and mass transformations on a planetary scale. In previous work we introduce the importance of integrating entropy production over time to distinguish abiotic from biotic processes under transient conditions. Here we investigate the ramifications of modeling biological systems involving one or more spatial dimensions. When modeling systems over space, entropy production can be maximized either locally at each point in space asynchronously or globally over the system domain synchronously. We use a simple two-box model inspired by two-layer ocean models to illustrate the differences in local versus global entropy maximization. Synthesis and oxidation of biological structure is modeled using two autocatalytic reactions that account for changes in community kinetics using a single parameter each. Our results show that entropy production can be increased if maximized over the system domain rather than locally, which has important implications regarding how biological systems organize and supports the hypothesis for multiple levels of selection and cooperation in biology for the dissipation of free energy.
Jet stream wind power as a renewable energy resource: little power, big impacts
Authors: Miller L. M. , Gans F. , Kleidon A.
Published: June 2011

Abstract. Jet streams are regions of sustained high wind speeds in the upper atmosphere and are seen by some as a substantial renewable energy resource. However, jet streams are nearly geostrophic flow, that is, they result from the balance between the pressure gradient and Coriolis force in the near absence of friction. Therefore, jet stream motion is associated with very small generation rates of kinetic energy to maintain the high wind velocities, and it is this generation rate that will ultimately limit the potential use of jet streams as a renewable energy resource. Here we estimate the maximum limit of jet stream wind power by considering extraction of kinetic energy as a term in the free energy balance of kinetic energy that describes the generation, depletion, and extraction of kinetic energy. We use this balance as the basis to quantify the maximum limit of how much kinetic energy can be extracted sustainably from the jet streams of the global atmosphere as well as the potential climatic impacts of its use. We first use a simple thought experiment of geostrophic flow to demonstrate why the high wind velocities of the jet streams are not associated with a high potential for renewable energy generation. We then use an atmospheric general circulation model to estimate that the maximum sustainable extraction from jet streams of the global atmosphere is about 7.5 TW. This estimate is about 200-times less than previous estimates and is due to the fact that the common expression for instantaneous wind power ½ ρ v3 merely characterizes the transport of kinetic energy by the flow, but not the generation rate of kinetic energy. We also find that when maximum wind power is extracted from the jet streams, it results in significant climatic impacts due to a substantial increase of heat transport across the jet streams in the upper atmosphere. This results in upper atmospheric temperature differences of >20 °C, greater atmospheric stability, substantial reduction in synoptic activity, and substantial differences in surface climate. We conclude that jet stream wind power does not have the potential to become a significant source of renewable energy.
Long term variability of the annual hydrological regime and sensitivity to temperature phase shifts in Saxony/Germany
Authors: Renner M. , Bernhofer C.
Published: June 2011

Abstract. Recently, climatological studies report observational evidence of changes in the timing of the seasons, such as earlier timing of the annual cycle of surface temperature, earlier snow melt and earlier onset of the phenological spring season. Also hydrological studies report earlier timing and changes in monthly streamflows. From a water resources management perspective, there is a need to quantitatively describe the variability in the timing of hydrological regimes and to understand how climatic changes control the seasonal water budget of river basins. Here, the timing of hydrological regimes from 1930–2009 was investigated in a network of 27 river gauges in Saxony/Germany through a timing measure derived by harmonic function approximation of annual periods of runoff ratio series. The timing measure proofed to be robust and equally applicable to both mainly pluvial river basins and snow melt dominated regimes. We found that the timing of runoff ratio is highly variable, but markedly coherent across the basins analysed. Differences in average timing are largely explained by basin elevation. Also the magnitude of low frequent changes in the seasonal timing of streamflow and the sensitivity to the changes in the timing of temperature increase with basin elevation. This sensitivity is in turn related to snow storage and release, whereby snow cover dynamics in late winter explain a large part of the low- and high-frequency variability. A trend analysis based on cumulative anomalies revealed a common structural break around the year 1988. While the timing of temperature shifted earlier by 4 days, accompanied by a temperature increase of 1 K, the timing of runoff ratio within higher basins shifted towards occurring earlier about 1 to 3 weeks. This accelerated and distinct change indicates, that impacts of climate change on the water cycle may be strongest in higher, snow melt dominated basins.
Brief communication "On one mechanism of low frequency variability of the Antarctic Circumpolar Current"
Authors: Derzho O. G. , de Young B.
Published: June 2011

Abstract. In this paper we present a simple analytical model for low frequency and large scale variability of the Antarctic Circumpolar Current (ACC). The physical mechanism of the variability is related to temporal and spatial variations of the cyclonic mean flow (ACC) due to circularly propagating nonlinear barotropic Rossby wave trains. It is shown that the Rossby wave train is a fundamental mode, trapped between the major fronts in the ACC. The Rossby waves are predicted to rotate with a particular angular velocity that depends on the magnitude and width of the mean current. The spatial structure of the rotating pattern, including its zonal wave number, is defined by the specific form of the stream function-vorticity relation. The similarity between the simulated patterns and the Antarctic Circumpolar Wave (ACW) is highlighted. The model can predict the observed sequence of warm and cold patches in the ACW as well as its zonal number.
Mesoscale variability of water masses in the Arabian Sea as revealed by ARGO floats
Authors: Carton X. , L'Hegaret P.
Published: June 2011

Abstract. By analysing ARGO float data over the last four years, some aspects of the mesoscale variability of water masses in the Arabian Sea are described. The Red Sea Water outflow is strong in the Southwestern Gulf of Aden, in particular when a cyclonic gyre predominates in this region. Salinities of 36.5 and temperatures of 16 °C are found there between 600 and 1000 m depths. The Red Sea Water is more dilute in the eastern part of the Gulf, and fragments of this water mass can be advected offshore across the gulf or towards its northern coast by the regional gyres. The Red Sea Water outflow is also detected along the northeastern coast of Socotra, and fragments of RSW are found between one and three degrees of latitude north of this island. In the whole Gulf of Aden, the correlation between the deep motions of the floats and the SSH measured by altimetry is strong, at regional scale. The finer scale details of the float trajectories are more often related to the anomalous water masses that they encounter. The Persian Gulf Water (PGW) is found in the float profiles near Ras ash Sharbatat (near 57° E, 18° N), again with 36.5 in salinity and about 18–19 °C in temperature. These observations were achieved in winter when the southwestward monsoon currents can advect PGW along the South Arabian coast. Fragments of PGW are found in the Arabian Sea between 18 and 20° N and 63 and 65° E, showing that this water mass can escape the Gulf of Oman southeastward, in particular during summer.
Minkowski Tensor Shape Analysis of Cellular, Granular and Porous Structures
Authors: Schröder‐Turk G. E. , Mickel W. , Kapfer S. C. , Klatt M. A. , Schaller F. M. , Hoffmann M. J. F. , Kleppmann N. , Armstrong P. , Inayat A. , Hug D. , Reichelsdorfer M. , Peukert W. , Schwieger W. , Mecke K.
Published: June 2011

Predicting physical properties of materials with spatially complex structures is one of the most challenging problems in material science. One key to a better understanding of such materials is the geometric characterization of their spatial structure. Minkowski tensors are tensorial shape indices that allow quantitative characterization of the anisotropy of complex materials and are particularly well suited for developing structure‐property relationships for tensor‐valued or orientation‐dependent physical properties. They are fundamental shape indices, in some sense being the simplest generalization of the concepts of volume, surface and integral curvatures to tensor‐valued quantities. Minkowski tensors are based on a solid mathematical foundation provided by integral and stochastic geometry, and are endowed with strong robustness and completeness theorems. The versatile definition of Minkowski tensors applies widely to different types of morphologies, including ordered and disordered structures. Fast linear‐time algorithms are available for their computation. This article provides a practical overview of the different uses of Minkowski tensors to extract quantitative physically‐relevant spatial structure information from experimental and simulated data, both in 2D and 3D. Applications are presented that quantify (a) alignment of co‐polymer films by an electric field imaged by surface force microscopy; (b) local cell anisotropy of spherical bead pack models for granular matter and of closed‐cell liquid foam models; (c) surface orientation in open‐cell solid foams studied by X‐ray tomography; and (d) defect densities and locations in molecular dynamics simulations of crystalline copper.
An Unusual (R)‐Selective Epoxide Hydrolase with High Activity for Facile Preparation of Enantiopure Glycidyl Ethers
Authors: Zhao Jing , Chu Yan‐Yan , Li Ai‐Tao , Ju Xin , Kong Xu‐Dong , Pan Jiang , Tang Yun , Xu Jian‐He
Published: June 2011

A novel epoxide hydrolase (BMEH) with unusual (R)‐enantioselectivity and very high activity was cloned from Bacillus megaterium ECU1001. Highest enantioselectivities (E>200) were achieved in the bioresolution of ortho‐substituted phenyl glycidyl ethers and para‐nitrostyrene oxide. Worthy of note is that the substrate structure remarkably affected the enantioselectivities of the enzyme, as a reversed (S)‐enantiopreference was unexpectedly observed for the ortho‐nitrophenyl glycidyl ether. As a proof‐of‐concept, five enantiopure epoxides (>99% ee) were obtained in high yields, and a gram‐scale preparation of (S)‐ortho‐methylphenyl glycidyl ether was then successfully performed within a few hours, indicating that BMEH is an attractive biocatalyst for the efficient preparation of optically active epoxides.
An Effective Synthetic Entry to Fused Benzimidazoles via Iodocyclization
Authors: Zhang Xu , Zhou Yu , Wang Hengshuai , Guo Diliang , Ye Deju , Xu Yungen , Jiang Hualiang , Liu Hong
Published: June 2011

A protocol for the synthesis of the fused heterocyclic polycyclic compounds pyrrole[1,2‐a]benzimidazoles, piperidine[1,2‐a]benzimidazoles and oxa‐fused benzimidazoles using iodine and silver nitrate by an exo‐dig or endo‐dig cyclization pathway at room temperature has been developed. Silver nitrate is a key additive for improving the yield, and the improvement is a result of this additive eliminating the influence of iodine ions (I−), which would otherwise lead to the formation of bis‐iodine by‐products. Cyclizations involving terminal and substituted alkynes were performed. Further functionalizations demonstrated that the iodo derivatives obtained are potential synthetic intermediates that can increase the molecular complexity.
A Practical Asymmetric Synthesis of Enantiopure Spiro[4,4]nonane‐1,6‐dione
Authors: Han Zhaobin , Wang Zheng , Ding Kuiling
Published: June 2011

A practical asymmetric synthesis of enantiopure spiro[4,4]nonane‐1,6‐dione, a valuable precursor for chiral ligand development, is reported. This synthetic strategy includes a kinetic resolution of the readily synthesized ketone precursor with a chiral quaternary carbon center by bioreduction with baker’s yeast as the key step, followed by a hydroformylation, oxidation, esterification and Dieckmann cyclization reaction sequence to generate the spiro five‐membered ring. It was found that the masking of the β‐ketone carbonyl group of enantiopure ethyl 1‐allyl‐2‐oxocyclopentanecarboxylate via formation of a ketal with 1,3‐diol derivative is necessary during the process of Dieckmann condensation in order to prevent its racemization under basic conditions. This method allows the gram‐scale preparation of both enantiomers of spiro[4,4]nonane‐1,6‐dione (1) with excellent enantiopurities (up to >99% ee) in the overall yields of 54% [(R)‐1] and 42% [(S)‐1], respectively. The practicality of the present synthetic procedure has provided a fundamental platform for the development of spiro[4,4]nonane‐1,6‐dione‐based chiral chemistry.
Rhodium‐Catalyzed Addition of α‐Keto Acid Chlorides with Terminal Alkynes
Authors: Kashiwabara Taigo , Tanaka Masato
Published: June 2011

The addition reaction of α‐keto acid chlorides with terminal alkynes proceeds in the presence of (acetylacetonato)dicarbonylrhodium used as catalyst to afford synthetically versatile (Z)‐γ‐chloro‐α‐oxo‐β,γ‐unsaturated ketones regio‐ and stereoselectively.
Chemoenzymatic One‐Pot Synthesis of γ‐Butyrolactones
Authors: Korpak Margarete , Pietruszka Jörg
Published: June 2011

The synthesis of enantio‐ and diastereomerically pure γ‐butyrolactones is described using a one‐pot, two‐enzyme cascade. Ethyl 2‐methyl‐4‐oxopent‐2‐enoate (2) was reduced selectively first in a 1,4‐reduction using the old yellow enzyme (OYE1) [EC 1.6.99.1] and consecutively in a 1,2‐reduction by an alcohol dehydrogenase [EC 1.1.1.2].
Gold(I)‐Catalyzed Tandem Alkoxylation/Lactonization of γ‐Hydroxy‐α,β‐Acetylenic Esters
Authors: Ramón Rubén S. , Pottier Christophe , Gómez‐Suárez Adrián , Nolan Steven P.
Published: June 2011

The formation of 4‐alkoxy‐2(5H)‐furanones was achieved via tandem alkoxylation/lactonization of γ‐hydroxy‐α,β‐acetylenic esters catalyzed by 2 mol% of [2,6‐bis(diisopropylphenyl)imidazol‐2‐ylidine]gold bis(trifluoromethanesulfonyl)imidate [Au(IPr)(NTf2)]. The economic and simple procedure was applied to a series of various secondary propargylic alcohols allowing for yields of desired product of up to 95%. In addition, tertiary propargylic alcohols bearing mostly cyclic substituents were converted into the corresponding spiro derivatives. Both primary and secondary alcohols reacted with propargylic alcohols at moderate temperatures (65–80 °C) in either neat reactions or using 1,2‐dichloroethane as a reaction medium allowing for yields of 23–95%. In contrast to [Au(IPr)(NTf2)], reactions with cationic complexes such as [2,6‐bis(diisopropylphenyl)imidazol‐2‐ylidine](acetonitrile)gold tetrafluoroborate [Au(IPr)(CH3CN)][BF4] or (μ‐hydroxy)bis{[2,6‐bis(diisopropylphenyl)imidazol‐2‐ylidine]gold} tetrafluoroborate or bis(trifluoromethanesulfonyl)imidate – [{Au(IPr)}2(μ‐OH)][X] (X=BF4, NTf2) – mostly stop after the alkoxylation. Analysis of the intermediate proved the exclusive formation of the E‐isomer which allows for the subsequent lactonization.
A Short Way to Switchable Carbenes
Authors: Hashmi A. Stephen K. , Lothschütz Christian , Graf Katharina , Häffner Tobias , Schuster Andreas , Rominger Frank
Published: June 2011

A new, one‐step route to N‐heterocyclic oxo‐carbene complexes (NHOCs), representatives of chemo‐switchable NHC complexes, is reported. This simple procedure provides an easy access to gold, palladium and platinum complexes of these ligands.
Optical Properties of Organic Semiconductor Blends with Near‐Infrared Quantum‐Dot Sensitizers for Light Harvesting Applications
Authors: Itskos Grigorios , Othonos Andreas , Rauch Tobias , Tedde Sandro F. , Hayden Oliver , Kovalenko Maksym V. , Heiss Wolfgang , Choulis Stelios A.
Published: June 2011

We report an optical investigation of conjugated polymer (P3HT)/fullerene (PCBM) semiconductor blends sensitized by near‐infrared absorbing quantum dots (PbS QDs). A systematic series of samples that include pristine, binary and ternary blends of the materials are studied using steady‐state absorption, photoluminescence (PL) and ultrafast transient absorption. Measurements show an enhancement of the absorption strength in the near‐infrared upon QD incorporation. PL quenching of the polymer and the QD exciton emission is observed and predominantly attributed to intermaterial photoinduced charge transfer processes. Pump‐probe experiments show photo‐excitations to relax via an initial ultrafast decay while longer‐lived photoinduced absorption is attributed to charge transfer exciton formation and found to depend on the relative ratio of QDs to P3HT:PCBM content. PL experiments and transient absorption measurements indicate that interfacial charge transfer processes occur more efficiently at the fullerene/polymer and fullerene/nanocrystal interfaces compared to polymer/nanocrystal interfaces. Thus the inclusion of the fullerene seems to facilitate exciton dissociation in such blends. The study discusses important and rather unexplored aspects of exciton recombination and charge transfer processes in ternary blend composites of organic semiconductors and near‐infrared quantum dots for applications in solution‐processed photodetectors and solar cells.
Preparation of cellulosic ion exchange fiber using an ionic liquid as reaction reagent and medium
Authors: Chen Chunming , Yang Chi
Published: June 2011

A cellulosic ion exchange fiber (CIEF) was prepared by using room‐temperature ionic liquid 1‐(3‐chloro‐2‐hydroxypropyl)‐3‐methylimidazolium chloride as reaction reagent and medium. The results showed the degree of substitution of the CIEF was up to 0.78. The product was characterized by Fourier transform infrared spectrometry, thermogravimetric analysis, scanning electronic microscope. The thermal stability of the CIEF was over 200°C. The adsorption experiments of CIEF for Cr(VI) were performed. The adsorption capacity of CIEF for Cr(VI) was found to be 196.1 mg g−1 at 30°C. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011.
Programming microbial population dynamics by engineered cell–cell communication
Authors: Song Hao , Payne Stephen , Tan Cheemeng , You Lingchong
Published: June 2011

A major aim of synthetic biology is to program novel cellular behavior using engineered gene circuits. Early endeavors focused on building simple circuits that fulfill simple functions, such as logic gates, bistable toggle switches, and oscillators. These gene circuits have primarily focused on single‐cell behaviors since they operate intracellularly. Thus, they are often susceptible to cell–cell variations due to stochastic gene expression. Cell–cell communication offers an efficient strategy to coordinate cellular behavior at the population level. To this end, we review recent advances in engineering cell–cell communication to achieve reliable population dynamics, spanning from communication within single species to multispecies, from one‐way sender–receiver communication to two‐way communication in synthetic microbial ecosystems. These engineered systems serve as well‐defined model systems to better understand design principles of their naturally occurring counterparts and to facilitate novel biotechnology applications.
Application of image analysis in the fungal fermentation of Trichoderma reesei RUT‐C30
Authors: Choy Viviane , Patel Nilesh , Thibault Jules
Published: June 2011

Trichoderma reesei was grown in a stirred‐tank bioreactor (STB) and a reciprocating plate bioreactor (RPB) at four different agitation speeds. A semiautomatic image analysis protocol that was developed to characterize the mycelium morphology during the fermentation process based on four morphological types (unbranched, branched, entangled, and clumped microorganisms) was applied to study the effect of agitation on the morphology of T. reesei. It was shown via statistical validation that broth samples used for image analysis represented the whole population of the fungi in the bioreactor. High shear was found to be damaging to T. reesei grown in the STB. The gentler shear produced in the RPB was not detrimental to the microorganism even at higher agitation speed. Better productivity was obtained for T. reesei grown in the STB and the highest productivity, 0.121 IU/mL h, was obtained at 400 rpm. The morphological parameter, the hyphal growth unit, was found to be correlated to the productivity. Understanding the effect of agitation on the morphology and productivity of T. reesei could lead to the design of better bioreactors and the selection of operating conditions of bioreactors to optimize the production of cellulase. © 2011 American Institute of Chemical Engineers Biotechnol. Prog., 2011.
Particle morphology characterization and manipulation in biomass slurries and the effect on rheological properties and enzymatic conversion
Authors: Dibble Clare J. , Shatova Tatyana A. , Jorgenson Jennie L. , Stickel Jonathan J.
Published: June 2011

An improved understanding of how particle size distribution relates to enzymatic hydrolysis performance and rheological properties could enable enhanced biochemical conversion of lignocellulosic feedstocks. Particle size distribution can change as a result of either physical or chemical manipulation of a biomass sample. In this study, we employed image processing techniques to measure slurry particle size distribution and validated the results by showing that they are comparable to those from laser diffraction and sieving. Particle size and chemical changes of biomass slurries were manipulated independently and the resulting yield stress and enzymatic digestibility of slurries with different size distributions were measured. Interestingly, reducing particle size by mechanical means from about 1 mm to 100 μm did not reduce the yield stress of the slurries over a broad range of concentrations or increase the digestibility of the biomass over the range of size reduction studied here. This is in stark contrast to the increase in digestibility and decrease in yield stress when particle size is reduced by dilute‐acid pretreatment over similar size ranges. © 2011 American Institute of Chemical Engineers Biotechnol. Prog., 2011
N‐Methylation of the Amide Bond by Methyltransferase Asm10 in Ansamitocin Biosynthesis
Authors: Wu Yingying , Kang Qianjin , Shang Guangdong , Spiteller Peter , Carroll Brian , Yu Tin‐Wein , Su Wenjin , Bai Linquan , Floss Heinz G.
Published: June 2011

Ansamitocins are potent antitumor agents produced by Actinosynnema pretiosum. As deduced from their structures, an N‐methylation on the amide bond is required among the various modifications. The protein encoded by asm10 belongs to the SAM‐dependent methyltransferase family. Through gene inactivation and complementation, asm10 was proved to be responsible for the N‐methylation of ansamitocins. Asm10 is a 33.0 kDa monomer, as determined by gel filtration. By using N‐desmethyl‐ansamitocin P‐3 as substrate, the optimal temperature and pH for Asm10 catalysis were determined to be 32 °C and 10.0, respectively. Asm10 also showed broad substrate flexibility toward other N‐desmethyl‐ansamycins and synthetic indolin‐2‐ones. Through site‐directed mutagenesis, Asp154 and Leu155 of Asm10 were confirmed to be essential for its catalysis, possibly through the binding of SAM. The characterization of this unique N‐methyltransferase has enriched the toolbox for engineering N‐methylated derivatives from both natural and synthetic compounds; this will allow known potential drugs to be modified.
Technique of temporary subcutaneous “Figure‐of‐eight” sutures to achieve hemostasis after removal of large‐caliber femoral venous sheaths
Authors: Cilingiroglu Mehmet , Salinger Michael , Zhao David , Feldman Ted
Published: June 2011

Over the last decade, significant advances have been made in percutaneous treatment of structural heart diseases. Many of these interventions require insertion of large caliber sheaths in the femoral veins. Manual compression, compression devices, and various closure devices have been used for removal of large‐sized venous sheaths. Here, we describe the use of a temporary subcutaneous “Figure‐of‐Eight” suture technique for venous access site closure after removal of large‐caliber sheaths. © 2011 Wiley‐Liss, Inc.
Transaortic flow velocity from dual‐source MDCT for the diagnosis of aortic stenosis severity
Authors: Schultz Carl J. , Papadopoulou Stella‐Lida , Moelker Adriaan , Nuis Rutger J. , Kate Gert J.R. Ten , Mollet Nico R. , Geleijnse Marcel L. , de Feyter Pim , de Jaegere Peter , Serruys Patrick W.
Published: June 2011

Objectives:

To describe a method for the estimation of transaortic flow from multidetector computer tomography (MDCT).

Background:

Cardiac MDCT may not allow instantaneous flow measurement yet the components of flow, namely, volume change over time and lumenal area are recorded.

Methods:

In 36 patients, the transaortic flow velocity was determined on transthoracic echocardiography and also with cardiac MDCT as follows: On MDCT an axial orientation through the aortic root was obtained so that the nadir of all three aortic leaflets could be seen simultaneously in one axial image. Aortic valve area (AVA) was determined by planimetry and left ventricular volumes by endocardial border mapping at every 5% increment of the RR intervals. Flow velocity was then calculated as the incremental ejection volume ÷ duration of the increment ÷ AVA.

Results:

The transthoracic echocardiography (TTE) peak velocity and MDCT peak velocity were highly correlated (r = 0.75, P < 0.01). Transaortic peak velocity was higher when measured by MDCT as compared to TTE, with respectively a median [IQ‐range] of 4.5 [2.9–5.3] and 4.0 [3.0–4.6], P < 0.01. For the diagnosis of severe aortic stenosis greater concordance with TTE peak velocity was seen with MDCT peak velocity (sensitivity 100%, specificity 76%) than with MDCT AVA (sensitivity 74%, specificity 76%).

Conclusions:

We show for the first time that transaortic flow velocity can be estimated by dual‐source MDCT and has a better sensitivity for the detection of severe aortic stenosis than AVA planimetry when compared to the gold standard of TTE peak flow velocity. © 2011 Wiley‐Liss, Inc.
Prognostic role of preprocedural glucose levels on short‐ and long‐term outcome in patients undergoing percutaneous coronary revascularization
Authors: Nusca Annunziata , Patti Giuseppe , Marino Francesco , Mangiacapra Fabio , D'Ambrosio Andrea , Di Sciascio Germano
Published: June 2011

Objectives: We investigated the prognostic role of preprocedural blood glucose levels (BGLs) on short‐ and long‐term outcome in patients undergoing elective percutaneous coronary intervention (PCI). Background: Hyperglycemia and hypoglycemia, with or without pre‐existing diabetes mellitus, are associated with adverse outcome in patients with coronary artery disease. Moreover, neointimal hyperplasia after coronary stent implantation is increased in presence of suboptimal glycemic control. Methods: Preprocedural BGLs were prospectively measured in 572 patients and predefined groups were considered: hypoglycemia ≤ 80 mg/dl; euglycemia 81–109 mg/dl; mild hyperglycemia 110–125 mg/dl; hyperglycemia ≥ 126 mg/dl. Primary end point was represented by the incidence of peri‐procedural myocardial infarction (MI) and secondary end point was the occurrence of major adverse cardiac events (MACE) at follow‐up. Results: Hypoglycemia was associated with an increased risk of peri‐procedural MI (51% vs 30%, 29%, and 37% in euglycemia, mild hyperglycemia and hyperglycemia groups, respectively; P for trend 0.025). After a mean follow‐up of 15 ± 8 months, the occurrence of MACE was 38% in the hypoglycemia group, 12% in the euglycemia group, 14% in the mild hyperglycemia and 22% in the hyperglycemia group (P < 0.001). The incidence of in‐stent restenosis and target vessel revascularization was also higher in patients with abnormal pre‐procedural BGLs (P for trend 0.007 and <0.001, respectively). Multivariate analysis confirmed hypoglycemia as a predictor of early and long‐term unfavorable cardiac prognosis (OR = 2.53, 95% CI 1.09‐5.81, P = 0.029 for peri‐procedural MI; OR = 2.91, 95% CI 1.26–6.69, P = 0.012 for MACE occurrence). Conclusions: We observed a significant association between preprocedural BGLs and adverse short‐and long‐term outcome in patients undergoing elective PCI. Thus, a careful glycemic monitoring should be recommended in all patients undergoing coronary stenting, irrespective of the diabetic status. © 2011 Wiley Periodicals, Inc.
Detection of Single Nucleotide Polymorphisms by a Gold Nanowire‐on‐Film SERS Sensor Coupled with S1 Nuclease Treatment
Authors: Yoo Seung Min , Kang Taejoon , Kim Bongsoo , Lee Sang Yup
Published: June 2011

Single nucleotide polymorphisms (SNPs) can serve as important biomarkers for genetic diseases, for which accurate detection of SNPs is essential for early diagnosis. We have developed a novel SNP sensor by combining a Au nanowire‐on‐film surface‐enhanced Raman scattering (SERS) platform with S1 nuclease reaction. The combined sensor system provides reproducible SERS signals only in the presence of perfectly matched target DNAs, to probe DNAs as a result of single‐stranded DNA‐specific degradation by S1 nuclease. Furthermore, point mutations in DNA causing Wilson disease and Avellino corneal dystrophy were successfully identified by this sensor, thereby indicating its practical ability to diagnose genetic diseases.