bluuebunny/crossref_metadata_2025_split huggingface dataset:
Inhibition of mammal Na+K+‐ATPase by diterpenes extracted from the Brazilian brown alga Dictyota cervicornis
Authors: Garcia Diogo Gomes , Bianco Everson Miguel , Santos Maria da Conceição Batista dos , Pereira Renato Crespo , Faria Mauro Velho de Castro , Teixeira Valeria Laneuville , Burth Patrícia 
Published: January 2009

AbstractThe dolastane diterpenes 4‐acetoxy‐9,14‐dihydroxydolast‐1(15),7‐diene (1) and 4,7‐diacetoxy‐14‐hydroxydolast‐1(15),8‐diene (2) were isolated from specimens of the alga Dictyota cervicornis collected from the Rio de Janeiro coast, Brazil. Chemical structures of the diterpenes were assigned by 1D and 2D NMR spectral data for the first time. Both substances inhibited Na+K+‐ATPase preparations from guinea‐pig brain or kidney, with the same inhibitory potency towards enzyme isoforms. The maximal inhibition obtained for 1 was 40% at a concentration of 0.5 mm in the incubation mixture, while it reached 80% for compound 2 at this concentration. Ouabain insensitive ATPases were inhibited by 1, but not by 2. Data comparing the inhibitory potency of these compounds with that of ouabain and oleic acid suggest a higher degree of selectivity of 2 towards the Na+K+‐pump. Cardiac glycosides such as ouabain are used classically in the treatment of heart failure, but alterations of Na+K+‐pump activity are also involved in several other diseases. Therefore, the study of compounds interfering with this pump activity is gaining further importance. Copyright © 2009 John Wiley & Sons, Ltd.
Antioxidant, antioedema and analgesic activities of Andrographis paniculata extracts and their active constituent andrographolide
Authors: Lin F. L. , Wu S. J. , Lee S. C. , Ng L. T. 
Published: January 2009

AbstractAndrographis paniculata (AP), a popular ingredient of Oriental folk medicine, is commonly used for treating infection, inflammation, fever and diarrhoea. In this study, extracts prepared from cultivated AP and their active constituent andrographolide were evaluated for antioxidant, antioedema and analgesic activities. The results showed that the aqueous AP extract (AP‐H2O) exhibited a greater antioxidant activity than the ethanol AP extract (AP‐EtOH) in all model systems tested. At a concentration of 50 µg/mL, the free radical scavenging, xanthine oxidase inhibition and antilipid peroxidation activities for AP‐H2O were 66.8%, 57.3% and 65.3%, respectively, and for AP‐EtOH were 57.8%, 52.6% and 34.2%, respectively. At a dosage of 100 mg/kg, AP‐H2O and andrographolide, but not AP‐EtOH, showed antioedema and analgesic activities. In phytochemical analysis, AP‐H2O showed a higher concentration of total flavanoid but a lower phenol content than AP‐EtOH. In conclusion, AP‐H2O was more potent than AP‐EtOH in antioxidant activities. Furthermore, compared with andrographolide, AP‐H2O as an extract also appears to possess potent antioedema and analgesic activities. Copyright © 2009 John Wiley & Sons, Ltd.
A combined wave‐number‐‐frequency and time‐extended EOF approach for tracking the progress of modes of large‐scale organized tropical convection
Authors: Roundy Paul E. , Schreck III Carl J. 
Published: January 2009

AbstractAn algorithm combining filtering in the wave‐number‐‐frequency domain with time‐extended empirical orthogonal function (EEOF) analysis is developed and applied to diagnose and track signals associated with modes of organized moist deep convection in the Tropics. The wave‐number‐‐frequency spectrum of outgoing long‐wave radiation (OLR) is broken down into five broad filter bands in order to concentrate signals associated with the Madden–Julian oscillation, convectively coupled equatorial Rossby, Kelvin, and mixed Rossby–gravity waves, easterly waves, and low‐frequency variations such as the El Niño/Southern Oscillation (ENSO). The EEOF patterns are obtained from analysis of the filtered data, and principal component (PC) time series are generated by projection of temporally smoothed, but otherwise unfiltered data onto the EEOF patterns. Filtered data are reconstructed by taking the product of the EEOF patterns and the corresponding PCs. These reconstructed data compare well with unfiltered OLR anomalies and with OLR anomalies filtered in the wave‐number‐‐frequency domain for the same modes. The method is easily applied in real time since results are not influenced by the proximity to the end of the dataset. Copyright © 2009 Royal Meteorological Society
The diabatic heat budget of the upper troposphere and lower/mid stratosphere in ECMWF reanalyses
Authors: Fueglistaler S. , Legras B. , Beljaars A. , Morcrette J.‐J. , Simmons A. , Tompkins A. M. , Uppala S. 
Published: January 2009

AbstractWe present an analysis of the diabatic terms in the thermodynamic energy equation from ERA‐40 and the ECMWF reanalysis ERA‐Interim. We analyse the clear‐sky radiative heating, the cloud radiative effects, and the impact from latent heat exchange and mixing. The diabatic heat budget is closed with the calculation of the temperature assimilation increment. The previously noted excessive tropospheric circulation at low latitudes in ERA‐40 is also reflected in the diabatic heat budget. The temperature increment acts to cool the excessive model heating. Conversely, ERA‐Interim requires heating from the assimilation increment at low latitudes, suggesting too little convection. In the tropical tropopause layer (TTL), both reanalyses show a strong heating from the interaction of clouds with radiation, but lack of reliable independent estimates renders the role of clouds uncertain. Both reanalyses show cooling in the TTL by the assimilation increment, suggesting that the models may overestimate the cloud radiative heating, or that the convective parametrization scheme has difficulties in capturing the thermal effects of deep convection. In the stratosphere, ERA‐40 shows unrealistic radiative heating due to problems in the temperature profile. The diabatic heat balance is dominated by the assimilation increment, and the residual circulation is much faster than in ERA‐Interim. Conversely, ERA‐Interim is better balanced and requires a substantially smaller temperature increment. Its structure and magnitude of radiative heating/cooling at low/high latitudes is quite realistic. Overall, ERA‐Interim provides a much improved residual circulation, but uncertainties in the magnitude of terms in particular around the tropical tropopause remain large. Copyright © 2009 Royal Meteorological Society
In silico methods for predicting metabolism and mass fragmentation applied to quetiapine in liquid chromatography/time‐of‐flight mass spectrometry urine drug screening
Authors: Pelander Anna , Tyrkkö Elli , Ojanperä Ilkka 
Published: January 2009

AbstractCurrent in silico tools were evaluated for their ability to predict metabolism and mass spectral fragmentation in the context of analytical toxicology practice. A metabolite prediction program (Lhasa Meteor), a metabolite detection program (Bruker MetaboliteDetect), and a fragmentation prediction program (ACD/MS Fragmenter) were used to assign phase I metabolites of the antipsychotic drug quetiapine in the liquid chromatography/time‐of‐flight mass spectrometry (LC/TOFMS) accurate mass data from ten autopsy urine samples. In the literature, the main metabolic routes of quetiapine have been reported to be sulfoxidation, oxidation to the corresponding carboxylic acid, N‐ and O‐dealkylation and hydroxylation. Of the 14 metabolites predicted by Meteor, eight were detected by LC/TOFMS in the urine samples with use of MetaboliteDetect software and manual inspection. An additional five hydroxy derivatives were detected, but not predicted by Meteor. The fragment structures provided by ACD/MS Fragmenter software confirmed the identification of the metabolites. Mean mass accuracy and isotopic pattern match (SigmaFit) values for the fragments were 2.40 ppm (0.62 mDa) and 0.010, respectively. ACD/MS Fragmenter, in particular, allowed metabolites with identical molecular formulae to be differentiated without a need to access the respective reference standards or reference spectra. This was well exemplified with the hydroxy/sulfoxy metabolites of quetiapine and their N‐ and O‐dealkylated forms. The procedure resulted in assigning 13 quetiapine metabolites in urine. The present approach is instrumental in developing an extensive database containing exact monoisotopic masses and verified retention times of drugs and their urinary metabolites for LC/TOFMS drug screening. Copyright © 2009 John Wiley & Sons, Ltd.
Aquatic plant‐derived changes in oil sands naphthenic acid signatures determined by low‐, high‐ and ultrahigh‐resolution mass spectrometry
Authors: Headley John V. , Peru Kerry M. , Armstrong Sarah A. , Han Xiumei , Martin Jonathan W. , Mapolelo Mmilili M. , Smith Donald F. , Rogers Ryan P. , Marshall Alan G. 
Published: January 2009

AbstractMass spectrometry is a common tool for studying the fate of complex organic compound mixtures in oil sands processed water (OSPW), but a comparison of low‐, high‐ (∼10 000), and ultrahigh‐resolution (∼400 000) instrumentation for this purpose has not previously been made. High‐resolution quadrupole time‐of‐flight mass spectrometry (QTOF MS) and ultrahigh‐resolution Fourier transform ion cyclotron resonance mass spectrometry (FT‐ICR MS), with negative‐ion electrospray ionization, provided evidence for the selective dissipation of components in OSPW. Dissipation of oil sands naphthenic acids (NAs with general formula CnH2n+zO2 where n is the number of carbon atoms, and Z is zero or a negative even number describing the number of rings) was masked (by components such as fatty acids, O3, O5, O6, O7, SO2, SO3, SO4, SO5, SO6, and NO4 species) at low resolution (1000) when using a triple quadrupole mass spectrometer. Changes observed in the relative composition of components in OSPW appear to be due primarily to the presence of plants, specifically cattails (Typha latifolia) and their associated microorganisms. The observed dissipation included a range of heteratomic species containing O2, O3, O4, and O5, present in Athabasca oil sands acid extracts. For the heteratomic O2 species, namely naphthenic acids, an interesting structural relationship suggests that low and high carbon number NAs are dissipated by the plants preferentially, with a minimum around C14/C15. Other heteratomic species containing O6, O7, SO2, SO3, SO4, SO5, SO6, and NO4 appear to be relatively recalcitrant to the cattails and were not dissipated to the same extent in planted systems. Copyright © 2009 John Wiley & Sons, Ltd.
Artifacts in Fourier transform mass spectrometry
Authors: Mathur Raman , O'Connor Peter B. 
Published: January 2009

AbstractRecent work on a new, higher sensitivity preamplifier design for Fourier transform ion cyclotron resonance mass spectrometry (FTICRMS) revealed a number of artifact peaks (spectral features) which do not contain useful chemical information. In order to determine the cause of these artifacts and eliminate them, these severely distorted spectra were compared with similarly distorted signal models. The source of several common signal processing artifacts was thereby determined and correlated to radio‐frequency interference (RFI) noise and saturation of the amplifier and/or the digitizer. Under such conditions, the fast Fourier transform (FFT) generates spectral artifact peaks corresponding to harmonics and mixing frequencies of the real signal peaks and RFI frequencies. While this study was done using FTICRMS data, it is important to stress that these artifacts are inherent to the digitization and FFT process and thus are relevant to any FT‐based MS instrument, including the orbitrap and FT ion trap. Copyright © 2009 John Wiley & Sons, Ltd.
On the calibration of continuous, high‐precision δ18O and δ2H measurements using an off‐axis integrated cavity output spectrometer
Authors: Wang Lixin , Caylor Kelly K. , Dragoni Danilo 
Published: January 2009

AbstractThe 18O and 2H of water vapor serve as powerful tracers of hydrological processes. The typical method for determining water vapor δ18O and δ2H involves cryogenic trapping and isotope ratio mass spectrometry. Even with recent technical advances, these methods cannot resolve vapor composition at high temporal resolutions. In recent years, a few groups have developed continuous laser absorption spectroscopy (LAS) approaches for measuring δ18O and δ2H which achieve accuracy levels similar to those of lab‐based mass spectrometry methods. Unfortunately, most LAS systems need cryogenic cooling and constant calibration to a reference gas, and have substantial power requirements, making them unsuitable for long‐term field deployment at remote field sites. A new method called Off‐Axis Integrated Cavity Output Spectroscopy (OA‐ICOS) has been developed which requires extremely low‐energy consumption and neither reference gas nor cryogenic cooling. In this report, we develop a relatively simple pumping system coupled to a dew point generator to calibrate an ICOS‐based instrument (Los Gatos Research Water Vapor Isotope Analyzer (WVIA) DLT‐100) under various pressures using liquid water with known isotopic signatures. Results show that the WVIA can be successfully calibrated using this customized system for different pressure settings, which ensure that this instrument can be combined with other gas‐sampling systems. The precisions of this instrument and the associated calibration method can reach ∼0.08‰ for δ18O and ∼0.4‰ for δ2H. Compared with conventional mass spectrometry and other LAS‐based methods, the OA‐ICOS technique provides a promising alternative tool for continuous water vapor isotopic measurements in field deployments. Copyright © 2009 John Wiley & Sons, Ltd.
Profiling the metabolic differences of anthraquinone derivatives using liquid chromatography/tandem mass spectrometry with data‐dependent acquisition
Authors: Song Rui , Lin Hui , Zhang Zunjian , Li Zhe , Xu Lei , Dong Haijuan , Tian Yuan 
Published: January 2009

AbstractThis work concentrates on the in vitro metabolism of anthraquinone derivatives from rhubarb. Different metabolic reactions for anthraquinone derivatives were dependent on the substituent group in the skeleton. Monohydroxylation in the exocyclic methyl group was the major metabolic modification for emodin. Aloe‐emodin containing a hydroxymethyl group was mainly metabolized through a methylation reaction. For rhein, both hydrogenation and methyl substitution on the benzene ring were the major metabolic reactions. Hydroxyl substitution on the benzene ring was the predominant metabolic reaction for chrysophanol. For physcion, demethylation of the exocyclic methoxy group was the most important metabolic reaction. Copyright © 2009 John Wiley & Sons, Ltd.
Invertebrate drift patterns in a regulated river: dams, periphyton biomass or longitudinal patterns?
Authors: Tonkin Jonathan D , Death Russell G , Joy Michael K 
Published: January 2009

AbstractMacroinvertebrate drift was sampled at 15 sites along the Tongariro River, New Zealand above and below two hydroelectric dams. Sixty‐seven invertebrate taxa were collected in the drift. Trichoptera (31) were the most diverse, followed by Diptera (13), Ephemeroptera (8) and Plecoptera (8). However, chironomidae were the numerically dominant taxa in the drift throughout the river and represented over 80% of all animals collected. Of these, Orthocladiinae and Diamesinae were the most abundant. Taxonomic richness declined with distance downstream and peaked at sites with intermediate levels of periphyton biomass. The per cent of Ephemeroptera, Plecoptera and Trichoptera (EPT) was 3–4 times higher in the unregulated section of the river and declined exponentially with both distance downstream and increase in periphyton biomass, but densities were similar along the river. Of the measured environmental variables periphyton biomass was most closely linked with drift community structure. Periphyton biomass was six times higher in the lower section of the river than the upper unregulated section. The autocorrelation between periphyton biomass and distance downstream complicates the interpretation of results. However, because of the distinct differences between above and below dam sections of river in periphyton biomass and the strong link between it and invertebrate drift we suggest that the alteration of flow patterns by the hydroelectric dams and the associated shift in periphyton biomass is the most likely explanation for invertebrate drift patterns in the river. Copyright © 2009 John Wiley & Sons, Ltd.
Nanoscale imaging of microbial pathogens using atomic force microscopy
Authors: Alsteens David , Dague Etienne , Verbelen Claire , Andre Guillaume , Dupres Vincent , Dufrêne Yves F. 
Published: January 2009

AbstractThe nanoscale exploration of microbes using atomic force microscopy (AFM) is an exciting research field that has expanded rapidly in the past years. Using AFM topographic imaging, investigators can visualize the surface structure of live cells under physiological conditions and with unprecedented resolution. In doing so, the effect of drugs and chemicals on the fine cell surface architecture can be monitored. Real‐time imaging offers a means to follow dynamic events such as cell growth and division. In parallel, chemical force microscopy (CFM), in which AFM tips are modified with specific functional groups, allows researchers to measure interaction forces, such as hydrophobic forces, and to resolve nanoscale chemical heterogeneities on cells, on a scale of only ∼25 functional groups. Lastly, molecular recognition imaging using spatially resolved force spectroscopy, dynamic recognition imaging or immunogold detection, enables microscopists to localize specific receptors, such as cell adhesion proteins or antibiotic binding sites. These noninvasive nanoscale analyses provide new avenues in pathogenesis research, particularly for investigating the action mode of antimicrobial drugs, and for elucidating the molecular basis of pathogen–host interactions Copyright © 2009 John Wiley & Sons, Inc.This article is categorized under:

Nanotechnology Approaches to Biology > Nanoscale Systems in Biology
Noise in biological circuits
Authors: Simpson Michael L. , Cox Chris D. , Allen Michael S. , McCollum James M. , Dar Roy D. , Karig David K. , Cooke John F. 
Published: January 2009

AbstractNoise biology focuses on the sources, processing, and biological consequences of the inherent stochastic fluctuations in molecular transitions or interactions that control cellular behavior. These fluctuations are especially pronounced in small systems where the magnitudes of the fluctuations approach or exceed the mean value of the molecular population. Noise biology is an essential component of nanomedicine where the communication of information is across a boundary that separates small synthetic and biological systems that are bound by their size to reside in environments of large fluctuations. Here we review the fundamentals of the computational, analytical, and experimental approaches to noise biology. We review results that show that the competition between the benefits of low noise and those of low population has resulted in the evolution of genetic system architectures that produce an uneven distribution of stochasticity across the molecular components of cells and, in some cases, use noise to drive biological function. We review the exact and approximate approaches to gene circuit noise analysis and simulation, and review many of the key experimental results obtained using flow cytometry and time‐lapse fluorescent microscopy. In addition, we consider the probative value of noise with a discussion of using measured noise properties to elucidate the structure and function of the underlying gene circuit. We conclude with a discussion of the frontiers of and significant future challenges for noise biology. Copyright © 2009 John Wiley & Sons, Inc.This article is categorized under:

Nanotechnology Approaches to Biology > Cells at the Nanoscale
Commercialization of nanotechnology
Authors: Hobson David W. 
Published: January 2009

AbstractThe emerging and potential commercial applications of nanotechnologies clearly have great potential to significantly advance and even potentially revolutionize various aspects of medical practice and medical product development. Nanotechnology is already touching upon many aspects of medicine, including drug delivery, diagnostic imaging, clinical diagnostics, nanomedicines, and the use of nanomaterials in medical devices. This technology is already having an impact; many products are on the market and a growing number is in the pipeline. Momentum is steadily building for the successful development of additional nanotech products to diagnose and treat disease; the most active areas of product development are drug delivery and in vivo imaging. Nanotechnology is also addressing many unmet needs in the pharmaceutical industry, including the reformulation of drugs to improve their bioavailability or toxicity profiles. The advancement of medical nanotechnology is expected to advance over at least three different generations or phases, beginning with the introduction of simple nanoparticulate and nanostructural improvements to current product and process types, then eventually moving on to nanoproducts and nanodevices that are limited only by the imagination and limits of the technology itself. This review looks at some recent developments in the commercialization of nanotechnology for various medical applications as well as general trends in the industry, and explores the nanotechnology industry that is involved in developing medical products and procedures with a view toward technology commercialization Copyright © 2009 John Wiley & Sons, Inc.This article is categorized under:

Toxicology and Regulatory Issues in Nanomedicine > Regulatory and Policy Issues in Nanomedicine
Nanoparticle therapeutics: a personal perspective
Authors: McNeil Scott E. 
Published: January 2009

AbstractNanotechnology offers many potential benefits to cancer research through passive and active targeting, increased solubility/bioavailablility, and novel therapies. However, preclinical characterization of nanoparticles is complicated by the variety of materials, their unique surface properties, reactivity, and the task of tracking the individual components of multicomponent, multifunctional nanoparticle therapeutics in in vivo studies. There are also regulatory considerations and scale‐up challenges that must be addressed. Despite these hurdles, cancer research has seen appreciable improvements in efficacy and quite a decrease in the toxicity of chemotherapeutics because of ‘nanotech’ formulations, and several engineered nanoparticle clinical trials are well underway. This article reviews some of the challenges and benefits of nanomedicine for cancer therapeutics and diagnostics. © 2009 John Wiley & Sons, Inc.This article is categorized under:

Therapeutic Approaches and Drug Discovery > Emerging Technologies
The Versatility of Solid‐State Metathesis Reactions: From Rare Earth Fluorides to Carbodiimides
Authors: Unverfehrt Leonid , Glaser Jochen , Ströbele Markus , Tragl Sonja , Gibson Katharina , Meyer H.‐Jürgen 
Published: January 2009

AbstractThe new carbodiimide compounds LaF(CN2) and LiPr2F3(CN2)2 were obtained as crystalline powders by solid‐state metathesis reactions from 1:1 molar ratios of REF3 (RE = rare earth) and Li2(CN2) at temperatures between 500 and 700 °C over 4 days in fused copper ampoules. Higher proportions of Li2(CN2) in reactions yielded RE2(CN2)3 compounds, including the new Eu2(CN2)3. Single‐crystal structure refinements were performed for LaF(CN2) and LiPr2F3(CN2)2. Homologous LiRE2F3(CN2)2 compounds with RE = Ce, Pr, Nd, Sm, Eu, Gd were assigned by isotypic indexing of their XRD patterns. The crystal structure of LaF(CN2) contains planar [La3F3] layers being interconnected by carbodiimide ions, and is related with that of the mineral bastnäsite (REF(CO3)).