bluuebunny/crossref_metadata_2025_split huggingface dataset:
Cultivation‐based strategies to find efficient marine biocatalysts
Authors: Rodrigues Carlos J. C. , Pereira Ricardo F.S. , Fernandes Pedro , Cabral Joaquim M.S. , de Carvalho Carla C. C. R. 
Published: March 2017

AbstractMarine bacteria have evolved to survive in the marine environment by using unique physiological, biochemical and metabolic features and the ability to produce enzymes and compounds which may have commercial value. The Azores archipelago presents several ecosystems with strong volcanic activity where bacteria thrive under e.g. high temperatures. In this study, samples collected in the island of São Miguel were screened for biocatalysts possessing e.g. lipase, esterase, amylase, and inulinase activities. After isolation of several hundred bacterial strains, high throughput screening methods allowed the fast identification of biocatalysts. The first cultivation tests were performed on 24‐wells microtiter plates with online oxygen monitoring and bacteria able to grow within 24 h were selected for further process development. Bacteria able to produce the desired enzymes were selected for the first round of tests. Four Bacillus strains presented high inulinase activity. The next step in process development was the determination of key parameters for enzyme activity such as temperature, pH, salinity and substrate concentration. The highest inulinase activity, 2.2 gsugars/gprotein h, was attained when the supernatant of a culture of a Bacillus subtilis strain was used in a magnetically stirred bioreactor. This study demonstrates how bacterial strains from marine environments may be used successfully in biotechnological processes.
A simple and cost‐effective HPLC‐UV method for the detection of levetiracetam in plasma/serum of patients with epilepsy
Authors: Engelbrecht Lynette , Grobler C. J. , Rheeders Malie 
Published: March 2017

AbstractA simple, fast and cost‐effective method was developed and validated for the determination of levetiracetam (LEV) in plasma/serum of patients using high performance liquid chromatography (HPLC) with ultraviolet detection. The stability of LEV plasma/serum samples over time and in different blood collection tubes was evaluated. Serum/plasma samples were deproteinized by methanol spiked with the internal standard, gabapentin. HPLC was carried out on a Venusil XBP C18, 250 × 4.6 mm, 5 μm column, at a flow rate of 1.0 mL/min and with mobile phase consisting of 50 mm potassium dihydrogen phosphate–acetonitrile at a pH of 5.5. The UV detector was set at 205 nm and 10 μL was injected. Total runtime was 15 min. Calibration curves were linear (correlation coefficient = 0.999) over a concentration range of 1–60 μg/mL. Relative standard deviation values for both the inter‐day and intra‐day precision and accuracy were <5% for the concentration range. The influence of different collection tubes and the effect of time on the stability of LEV was investigated. These factors may cause inaccuracies owing to drug–protein binding and interference in the matrix. This method is simple, fast, cost‐effective, reliable and accurate with minimal sample preparation for daily routine use in therapeutic drug monitoring.
Development of an LC–MS/MS method for quantification of two pairs of isomeric flavonoid glycosides and other ones in rat plasma: Application to pharmacokinetic studies
Authors: Zhang Sixi , Xie Yang , Wang Jing , Geng Yanmei , Zhou Yu , Sun Chengxin , Wang Guangshu 
Published: March 2017

AbstractA liquid chromatography–tandem mass spectrometry (LC–MS/MS) method was developed and validated for simultaneous determination of six flavonoid glycosides – isoorientin (1), orientin (2), 2″‐O‐β‐d‐xylopyranosyl isoorientin (3), 2″‐O‐β‐d‐xylopyranosyl isovitexin (4), 6‐C‐l‐α‐arabipyranosyl vitexin (5) and vitexin (6) – in rat plasma using isoquercitrin as the internal standard (IS). Plasma samples were prepared by a one‐step protein precipitation with acetonitrile. Chromatographic analysis was carried out on a 25 cm C18 column with a gradient mobile phase consisting of acetonitrile and 0.1% aqueous formic acid. Six analytes and IS were detected through electrospray ionization in negative‐ion selection reaction monitoring mode. The mass transitions were as follows: m/z 447.2 → 327.0 for 1, m/z 447.2 → 327.0 for 2, m/z 579.3 → 458.9 for 3, m/z 563.0 → 293.1 for 4, m/z 563.0 → 353.0 for 5, m/z 431.1 → 311.1 for 6, and m/z 463.1 → 300.2 for IS. Calibration curves exhibited good linearity (r2 > 0.9908) over a wide concentration range for all compounds. Intra‐ and inter‐day precision (RSD, %) at four different levels were both <14.2% and the accuracy (RE, %) ranged from −11.9 to 12.0%. The extraction recoveries of the six components ranged from 88.2 to 103.6%. The validated assay was successfully applied to the pharmacokinetic studies of the six components in male rat plasma after intravenous administration of total flavonoids of Scorzonera austriaca Wild.
Emerging applications of exosomes in cancer therapeutics and diagnostics
Authors: Inamdar Sahil , Nitiyanandan Rajeshwar , Rege Kaushal 
Published: March 2017

AbstractExosomes are nanoscale extracellular vesicles that are shed from different cells in the body. Exosomes encapsulate several biomolecules including lipids, proteins, and nucleic acids, and can therefore play a key role in cellular communication. These vesicles can be isolated from different body fluids and their small sizes make them attractive in various biomedical applications. Here, we review state‐of‐the art approaches in exosome isolation and purification, and describe their potential use in cancer vaccines, drug delivery, and diagnostics.
Discovering Drugs with DNA‐Encoded Library Technology: From Concept to Clinic with an Inhibitor of Soluble Epoxide Hydrolase
Authors: Belyanskaya Svetlana L. , Ding Yun , Callahan James F. , Lazaar Aili L. , Israel David I. 
Published: March 2017

AbstractDNA‐encoded chemical library technology was developed with the vision of its becoming a transformational platform for drug discovery. The hope was that a new paradigm for the discovery of low‐molecular‐weight drugs would be enabled by combining the vast molecular diversity achievable with combinatorial chemistry, the information‐encoding attributes of DNA, the power of molecular biology, and a streamlined selection‐based discovery process. Here, we describe the discovery and early clinical development of GSK2256294, an inhibitor of soluble epoxide hydrolase (sEH, EPHX2), by using encoded‐library technology (ELT). GSK2256294 is an orally bioavailable, potent and selective inhibitor of sEH that has a long half life and produced no serious adverse events in a first‐time‐in‐human clinical study. To our knowledge, GSK2256294 is the first molecule discovered from this technology to enter human clinical testing and represents a realization of the vision that DNA‐encoded chemical library technology can efficiently yield molecules with favorable properties that can be readily progressed into high‐quality drugs.
Oxidation of d‐Glucose to Glucaric Acid Using Au/C Catalysts
Authors: Solmi Stefania , Morreale Calogero , Ospitali Francesca , Agnoli Stefano , Cavani Fabrizio 
Published: March 2017

AbstractThe reactivity of Au and AuBi nanoparticles supported on activated carbon AC was investigated in the direct oxidation of glucose to glucaric acid. The catalysts were very active, regardless of the Au nanoparticles size, but the catalyst with the smallest average particle diameter was the least selective to glucaric acid because of the enhanced consecutive oxidative degradation of the intermediately formed gluconic acid. The reaction network included the fast oxidation of glucose to gluconic acid, which was the only primary product, and its consecutive oxidation into either glucaric acid or lighter mono and dicarboxylic acids. The best glucaric acid yield obtained with a AuBi/AC catalyst (Au/Bi 3:1) was 31 %, with 18 % residual gluconic acid. The control of reaction parameters was essential to achieving the best selectivity. Specifically, the glucose concentration turned out to be a critical parameter in relation to O2 pressure and to glucose/metal ratio.
Three‐Dimensional Assembly of PtNi Alloy Nanosticks with Enhanced Electrocatalytic Activity and Ultrahigh Stability for the Oxygen Reduction Reaction
Authors: Zhang Hongjie , Yi Baolian , Jiang Shangfeng , Zeng Yachao , Shao Zhigang 
Published: March 2017

AbstractA three‐dimensional (3D) assembly of PtNi alloy nanosticks (NSA) is synthesized through an effective organic solvothermal approach to enhance the specific activity and long‐term durability for the oxygen reduction reaction (ORR). The 3D PtNi NSA is composed of interconnected nanosticks with an average diameter of approximately 5 nm, which are confirmed to be of high crystallinity with ordered atomic arrangement of ORR‐favorable PtNi (111). After an electrochemical dealloying process, the surface of the nanosticks becomes rough with a large quantity of step‐like nanostructures, which are verified to effectively improve the ORR activity. The electrochemical results of half‐cell tests demonstrate that the 3D PtNi alloy NSA exhibits a 4.5 times higher mass activity than the Pt/C (20 wt%, JM) catalyst (0.58 A/mg) and a 5.1 times higher specific activity (742 μA/cm2). Most importantly, after the accelerated deterioration test, the 3D PtNi alloy NSA catalyst shows almost no activity decrease, both in half‐ and single‐cell tests. The 3D PtNi alloy NSA prepared here is indeed a promising electrocatalyst for practical electrocatalytic applications.
Catalytic Partial Oxidation of Cyclohexane by Bimetallic Ag/Pd Nanoparticles on Magnesium Oxide
Authors: Liu Xi , Conte Marco , He Qian , Knight David W. , Murphy Damien M. , Taylor Stuart H. , Whiston Keith , Kiely Christopher J. , Hutchings Graham J. 
Published: March 2017

AbstractThe liquid‐phase oxidation of cyclohexane to cyclohexanol and cyclohexanone was investigated by synthesizing and testing an array of heterogeneous catalysts comprising: monometallic Ag/MgO, monometallic Pd/MgO and a set of bimetallic AgPd/MgO catalysts. Interestingly, Ag/MgO was capable of a conversion comparable to current industrial routes of approximately 5 %, and with a high selectivity (up to 60 %) to cyclohexanol, thus making Ag/MgO an attractive system for the synthesis of intermediates for the manufacture of nylon fibres. Furthermore, following the doping of Ag nanoparticles with Pd, the conversion increased up to 10 % whilst simultaneously preserving a high selectivity to the alcohol. Scanning transmission electron microscopy and energy dispersive spectroscopy of the catalysts showed a systematic particle‐size‐composition variation with the smaller Ag–Pd nanoparticles being statistically richer in Pd. Analysis of the reaction mixture by electron paramagnetic resonance (EPR) spectroscopy coupled with the spin‐trapping technique showed the presence of large amounts of alkoxy radicals, thus providing insights for a possible reaction mechanism.
Reactivity Patterns of (Protonated) Compound II and Compound I of Cytochrome P450: Which is the Better Oxidant?
Authors: Li Xiao‐Xi , Postils Verònica , Sun Wei , Faponle Abayomi S. , Solà Miquel , Wang Yong , Nam Wonwoo , de Visser Sam P. 
Published: March 2017

AbstractThe cytochromes P450 are versatile enzymes in human physiology that perform substrate hydroxylation reactions extremely efficiently. In this work, we present results of a computational study on the reactivity patterns of Compound I, Compound II, and protonated Compound II with model substrates, and we address the question of which of these compounds is the most effective oxidant? All calculations, regardless of the substrate, implicated that Compound I is the superior oxidant of the three. However, Compound II and protonated Compound II were found to react with free energies of activation that are only a few kcal mol−1 higher in energy than those obtained with Compound I. Therefore, Compound II and protonated Compound II should be able to react with aliphatic groups with moderate C−H bond strengths. We have analysed all results in detail and have given electronic, thermochemical, valence bond, and molecular orbital rationalizations on the reactivity differences and explained experimental product distributions. Overall, the findings implied that alternative oxidants could operate alongside Compound I in complex reaction mechanisms of enzymatic and synthetic iron porphyrinoid complexes.
Coordination of Tetravalent Actinides (An=ThIV, UIV, NpIV, PuIV) with DOTA: From Dimers to Hexamers
Authors: Tamain Christelle , Dumas Thomas , Hennig Christoph , Guilbaud Philippe 
Published: March 2017

AbstractThree tetravalent actinide (AnIV) hexanuclear clusters with the octahedral core [An6(OH)4O4]12+ (AnIV=UIV, NpIV, PuIV) were structurally characterized in the solid state and in aqueous solution by using single‐crystal X‐ray diffraction, X‐ray absorption, IR, Raman, and UV/Vis spectroscopy. The observed structure, [An6(OH)4O4(H2O)8(HDOTA)4]⋅HCl/HNO3⋅n H2O (An=U(I), Np(II), Pu(III)), consists of a AnIV hexanuclear pseudo‐octahedral cluster stabilized by DOTA (1,4,7,10‐tetraazacyclododecane‐1,4,7,10‐tetraacetic acid) ligands. The six actinide atoms are connected through alternate μ3‐O2− and μ3‐OH− groups. Extended X‐ray absorption fine structure (EXAFS) investigations combined with UV/Vis spectroscopy provide evidence for the same local structure in moderate acidic and neutral aqueous solutions. The synthesis mechanism was partially elucidated and the main physicochemical properties (pH range stability, solubility, and protonation constant) of the cluster were determined. The results underline the importance of: 1) considering such polynuclear species in thermodynamic models, and 2) competing reactions between hydrolysis and complexation. It is interesting to note that the same synthesis route with thorium(IV) led to the formation of a dimer, Th2(H2O)10(H2DOTA)2⋅4 NO3⋅x H2O (IV), which contrasts to the structure of the other AnIV hexamers.
Ethylene production from diluted bioethanol solutions
Authors: Rossetti Ilenia , Compagnoni Matteo , De Guido Giorgia , Pellegrini Laura A. , Ramis Gianguido , Dzwigaj Stanislaw 
Published: March 2017

AbstractEthylene production by ethanol dehydration has been investigated over a set of zeolites with BEA structure in acidic form (HAlBEA). The effect on Ni addition (up to 0.03 g/g (3 mass%)) is explored as a means to improve ethylene selectivity limiting the formation of heavier byproducts. The reaction temperature has been varied between 300 and 500 °C and the effect of cofeeding water has been also explored. Both an increase of the operating temperature and of the water/ethanol ratio can improve stability of coking and thus catalyst life. The use of diluted bioethanol solutions was shown to be beneficial for catalyst stability. The effect of possible impurities present in less purified raw materials was also checked by testing two diluted second generation bioethanol solutions (0.5 and 0.9 g/g (50 and 90 mass%)). A first reactor layout and the integration with the bioethanol purification strategy are also proposed, including two purification options which are much less energy demanding than traditional rectification.
The protective effects of a novel fitness‐fatness index on all‐cause mortality among adults with cardiovascular disease
Authors: Frith Emily , Loprinzi Paul D. 
Published: March 2017

BackgroundWe evaluated the specific association between a fitness‐fatness index (FFI) and all‐cause mortality among a national sample of US adults with coronary artery disease, congestive heart failure, or myocardial infarction. This FFI has recently emerged in the literature as a novel index of health.HypothesisWe hypothesize that FFI will be inversely associated with mortality risk.MethodsThe FFI was calculated as cardiorespiratory fitness divided by waist‐to‐height ratio. Data from the 1999–2006 National Health and Nutrition Examination Survey were used to identify 1206 participants, ages 20 to 85. Person‐months of follow‐up were calculated from the date of interview until date of death or censoring on December 31, 2011, whichever came first.ResultsIn a Cox proportional hazards model, for every 1‐FFI‐unit increase, participants had a 6% reduced all‐cause mortality rate (hazard ratio [HR]: 0.94, 95% confidence interval [CI]: 0.91‐0.97, P = 0.001; N = 1206). Results were similar among those diagnosed with coronary artery disease (HR: 0.94, 95% CI: 0.90‐0.98, P = 0.007), congestive heart failure (HR: 0.95, 95% CI: 0.91‐0.99, P = 0.02), or myocardial infarction (HR: 0.96, 95% CI: 0.92‐0.99, P = 0.04). When examined in isolation, only fitness (and not fatness) was linked with survival benefits.ConclusionsIn this national sample, increased FFI was associated with reduced risk of all‐cause mortality; this association was driven by the beneficial effects of fitness. This underscores the importance of tailored cardiac rehabilitation programs designed to promote fitness, in particular, among cardiac populations.
Basophil activation test: Implementation and standardization between systems and between instruments
Authors: Depince-Berger Anne‐Emmanuelle , Sidi‐Yahya Khaled , Jeraiby Mohammed , Lambert Claude 
Published: March 2017

AbstractThe basophil activation test (BAT) is a good ex vivo alternative for measuring hypersensitivity to an allergen in sensitized patients but still lacks standardization. In this present study, we have implemented one of the systems and proposed inter‐systems, inter‐instrument standardization. Our method for basophil activation and labeling on whole blood: EDTA in one step using BasoflowEx® and FlowCast®. Setup on Navios and fluorescence targets converted to set up FACSCanto™ instrument. Our results: 1) A CD203c/CD63 (BasoflowEx) method was adapted for EDTA samples and simplified. 2) Final washing and concentration and use of time parameter help acquiring as many basophils as possible, spare acquisition time and noise. 3) The modified method was validated according to ISO15189 with a precision at 5.1% RCV, linearity between 1 and 1/8 of anti‐IgE stimulation. Results were very close with CCR3/CD63 system (FlowCast). 4) Standardization, between systems and even between instruments. Mean Fluorescence Intensity targets are proposed using standard beads (Cytocal®) middle peak: FITC = 19.4; PE = 28.8 on Navios® corresponding to FITC = 4,966; PE = 7,373 for FACSCanto. Data analyzed on common software (Kaluza®) were very closely correlated. 5) Co‐labeling of B cells (CD20+) gives the possibility to monitor a significant drop of basophils under stimulation that could explain some underestimation in case of strong hypersensitivity. In conclusion, BAT would strongly benefit from easy implementation [EDTA, one step stimulation/labeling, wash, full sample analysis over time parameter, B cell relative basophil count] and standardization of instrument settings on MFI targets whatever system or instrument is used. © 2017 International Society for Advancement of Cytometry
Choosing a new CD4 technology: Can statistical method comparison tools influence the decision?
Authors: Scott Lesley E. , Kestens Luc , Pattanapanyasat Kovit , Sukapirom Kasma , Stevens Wendy S. 
Published: March 2017

BackgroundMethod comparison tools are used to determine the accuracy, precision, agreement, and clinical relevance of a new or improved technology versus a reference technology. Guidelines for the most appropriate method comparison tools as well as their acceptable limits are lacking and not standardized for CD4 counting technologies.MethodsDifferent method comparison tools were applied to a previously published CD4 dataset (n = 150 data pairs) evaluating five different CD4 counting technologies (TruCOUNT, Dual Platform, FACSCount, Easy CD4, CyFlow) on a single specimen. Bland–Altman, percentage similarity, percent difference, concordance correlation, sensitivity, specificity and misclassification method comparison tools were applied as well as visualization of agreement with Passing Bablock and Bland–Altman scatter plots.ResultsThe FACSCount (median CD4 = 245 cells/µl) was considered the reference for method comparison. An algorithm was developed using best practices of the most applicable method comparison tools, and together with a modified heat map was found useful for method comparison of CD4 qualitative and quantitative results. The algorithm applied the concordance correlation for overall accuracy and precision, then standard deviation of the absolute bias and percentage similarity coefficient of variation to identify agreement, and lastly sensitivity and misclassification rates for clinical relevance.ConclusionCombining method comparison tools is more useful in evaluating CD4 technologies compared to a reference CD4. This algorithm should be further validated using CD4 external quality assessment data and studies with larger sample sizes. © 2017 International Clinical Cytometry Society
Biological soil crust and disturbance controls on surface hydrology in a semi‐arid ecosystem
Authors: Faist Akasha M. , Herrick Jeffrey E. , Belnap Jayne , Van Zee Justin W. , Barger Nichole N. 
Published: March 2017

AbstractBiological soil crust communities (biocrusts) play an important role in surface hydrologic processes in dryland ecosystems and can be dramatically altered with soil surface disturbance. In this study, through a simulated rainfall experiment, we examined biocrust hydrologic responses to disturbance (trampling and scraping) at different developmental stages on sandy soils on the Colorado Plateau. Our results showed that all disturbance treatments of the early‐successional light cyanobacterial biocrusts reduced runoff after 10 min of cumulative rainfall. Scraped and scraped + trampled treatments also reduced runoff after 30 min in the light biocrust when compared to the intact controls but runoff in the trampling treatments was not significantly reduced. Light biocrust sediment loss trended toward a decrease in total amount of sediment lost in all disturbance treatments but not significantly so. In contrast, trampling well‐developed dark cyano‐lichen biocrusts demonstrated an opposite response than the less‐developed light biocrusts and increased runoff after 30 min of cumulative rainfall and in total sediment loss relative to intact controls. Scraping in dark crusts did not increase runoff, implying that soil aggregate structure was important to the infiltration process. Well‐developed, intact dark biocrusts generally had lower runoff and sediment loss and highest aggregate stability, whereas the less‐developed light biocrusts were highest in runoff and sediment loss after disturbance when compared to the controls. These results suggest the importance of maintaining the well‐developed dark biocrusts, as they are beneficial for lowering runoff and reducing soil loss and redistribution on the landscape. These data also suggest that upslope patches of light biocrust may either support water transport to downslope vegetation patches or alternatively this runoff may place dark biocrust patches at risk of disruption and loss, given that light patches increase runoff and thus soil erosion potential.