bluuebunny/crossref_metadata_2025_split huggingface dataset:
Optimization of random PEGylation reactions by means of high throughput screening
Authors: Maiser Benjamin , Dismer Florian , Hubbuch Jürgen 
Published: August 2013

ABSTRACTSince the first FDA approval of a PEGylated product in 1990, so called random PEGylation reactions are still used to increase the efficacy of biopharmaceuticals and represent the major technology of all approved PEG‐modified drugs. However, the great influence of process parameters on PEGylation degree and the PEG‐binding site results in a lack of reaction specificity which can have severe impact on the product profile. Consequently, reproducible and well characterized processes are essential to meet increasing regulative requirements resulting from the quality‐by‐design (QbD) initiative, especially for this kind of modification type. In this study we present a general approach which combines the simple chemistry of random PEGylation reactions with high throughput experimentation (HTE) to achieve a well‐defined process. Robotic based batch experiments have been established in a 96‐well plate format and were analyzed to investigate the influence of different PEGylation conditions for lysozyme as model protein. With common SEC analytics highly reproducible reaction kinetics were measured and a significant influence of PEG‐excess, buffer pH, and reaction time could be investigated. Additional mono‐PEG‐lysozyme analytics showed the impact of varying buffer pH on the isoform distribution, which allowed us to identify optimal process parameters to get a maximum concentration of each isoform. Employing Micrococcus lysodeikticus based activity assays, PEG‐lysozyme33 was identified to be the isoform with the highest residual activity, followed by PEG‐lysozyme1. Based on these results, a control space for a PEGylation reaction was defined with respect to an optimal overall volumetric activity of mono‐PEG‐lysozyme isoform mixtures. Biotechnol. Bioeng. 2014;111: 104–114. © 2013 Wiley Periodicals, Inc.
Determination of newly synthesized lipoic acid–niacin dimer in rat plasma by UPLC/electrospray ionization tandem mass spectrometry: assay development, validation and application to a pharmacokinetic study
Authors: Chen Xiao , Gao Jingwen , Jiang Yiming , Huang Ping , Xie Yuhui , Pi Rongbiao , Zhu Shuzhen , Yao Meicun 
Published: August 2013

ABSTRACTA simple, sensitive and specific ultra‐performance liquid chromatography/tandem mass spectrometry (UPLC‐MS/MS) method was developed to determine the newly synthesized compound lipoic acid–niacin dimer (N2L) in plasma. Plasma samples were precipitated by methanol using tetrahydropalmatine as internal standard. Chromatographic separation was achieved on an Acquity BEH C18 (2.1 × 50 mm i.d., 1.7 µm) column; the mobile phase contains methanol and buffer solution (water with 0.5% formic acid and 10 mmol/L ammonium acetate). Multiple reaction monitoring (m/z 353.9 → 148.6 for N2L and m/z 356.0 → 192.0 for internal standard) was performed for detection and quantification. The method was validated to be rapid, specific, accurate and precise over the concentration range of 1–750 ng/mL; N2L was not stable on the bench‐top or during freeze–freeze‐thaw cycles in plasma, but was stable in the stock solution and after preparation in the autosampler for 24 h. The utility of the assay was confirmed by pharmacokinetic study of N2L in rats. Copyright © 2013 John Wiley & Sons, Ltd.
IRC 2012 survey report
Authors: Wu Mei‐Mei , Sonnenwald Diane H. 
Published: August 2013

AbstractEditor's SummaryThe Association for Information Science and Technology's International Relations Committee (IRC) surveyed organization members in the fall of 2012 to explore views on holding the ASIS&T Annual Meeting outside North America. The 247 respondents represented the total membership reasonably well with 70% from North America. About half stated they would likely or very likely attend an annual meeting in Europe, while 28% would probably attend a meeting in the Asia Pacific region. Holding a meeting outside North America could increase membership and expand perspectives. Concerns raised include travel permissions, timing in the academic year and total expense. Most respondents were open to joint conferences or co‐located meetings with other organizations every two to three years, though there was no consensus on which group or conference. The IRC will pursue investigations into coordinated conferences and locations.
The DCC's institutional engagements: Raising research data management capacity in UK higher education
Authors: Donnelly Martin 
Published: August 2013

AbstractEditor's SummaryThe United Kingdom's Digital Curation Centre (DCC), established in 2004, is the country's digital preservation and data management authority. From 2011 to mid‐2013 the DCC's Institutional Engagement program provided support for digital preservation and data management to 20 universities. The initiative was stimulated by the realization that research data leads to broader advances when shared, as well as by pressure from funders to implement formal data management practices. Experience with the first cohort of universities revealed differences in readiness for data management, the importance of a local champion and support staff and the need for dedicated funding. Unfamiliar but necessary working relationships emerged, as did the need to align institution requirements with funder priorities. Common challenges were planning for effective data management, data storage and training for researchers and staff. The DCC will apply the lessons learned with the first cohort to other higher educational institutions, adjusting its approach to serve each university's specific needs while promoting the shared purpose.
Alkaloids from Corals
Authors: Gao Chenghai , Yi Xiangxi , Huang Riming , Yan Fang , He Bijuan , Chen Bo 
Published: August 2013

AbstractAlkaloids, which are generally basic N‐containing compounds, have been found in a variety of natural sources. Recently, the interest in alkaloids from corals increased significantly due to their remarkable bioactivities. This review deals with the chemical structures and biological activities of alkaloids in corals. The literature has been covered up to June 2011, and a total of 102 alkaloids from the 51 publications are discussed and reviewed. Some of these compounds showed various biological properties, such as cytotoxic, antibacterial, insecticidal, antifouling, and other activities.
Abietane Diterpenes from Hyptis suaveolens
Authors: Prawatsri Saowanee , Suksamrarn Apichart , Chindaduang Anon , Rukachaisirikul Thitima 
Published: August 2013

AbstractInvestigation of the constituents of the whole plant of Hyptis suaveolens led to the isolation of three new abietane diterpenes, isosuaveolic acid (1), 8α,9α‐epoxysuaveolic acid (2), and 14‐O‐methylsuaveolic acid (3), together with eleven known compounds. The structures of 1–3 were established by spectroscopic methods and chemical correlations. Some isolates were tested for their antimycobacterial and cytotoxic activities.
Allelopathic Potential of Rapanea umbellata Leaf Extracts
Authors: Novaes Paula , Imatomi Maristela , Varela Rosa M. , Molinillo José M. G. , Lacret Rodney , Gualtieri Sonia C. J. , Macías Francisco A. 
Published: August 2013

AbstractThe stressful conditions associated with the Brazilian savanna (Cerrado) environment were supposed to favor higher levels of allelochemicals in Rapanea umbellata from this ecosystem. The allelopathic potential of R. umbellata leaf extracts was studied using the etiolated wheat coleoptile and standard phytotoxicity bioassays. The most active extract was selected to perform a bioassay‐guided isolation, which allowed identifying lutein (1) and (−)‐catechin (2) as potential allelochemicals. Finally, the general bioactivity of the two compounds was studied, which indicated that the presence of 1 might be part of the defense mechanisms of this plant.
Bioorganic Diversity of Rare Coriandrum sativum L. Honey: Unusual Chromatographic Profiles Containing Derivatives of Linalool/Oxygenated Methoxybenzene
Authors: Jerković Igor , Obradović Marina , Kuś Piotr Marek , Šarolić Mladenka 
Published: August 2013

AbstractThe compounds responsible for highly individual aroma profile of Coriandrum sativum L. honey were isolated by headspace solid‐phase microextraction (HS‐SPME; used fibers: A: polydimethylsiloxane (PDMS)/divinylbenzene (DVB) and B: divinylbenzene/carboxen/polydimethylsiloxane), as well as ultrasonic solvent extraction (USE; used solvents: A: pentane/Et2O 1 : 2 (v/v) and B: CH2Cl2) and analyzed by gas chromatography (GC) and mass spectrometry (MS). Unusual chromatographic profiles were obtained containing derivatives of linalool/oxygenated methoxybenzene. trans‐Linalool oxide (11.1%; 14.6%) dominated in the headspace, followed by other linalool derivatives (such as cis/trans‐anhydrolinalool oxide (5.0%; 5.9%), isomers of lilac aldehyde/alcohol (14.9%; 13.8%) or p‐menth‐1‐en‐9‐al (15.6%; 18.5%)), octanal, and several low‐molecular‐weight esters. The major compounds in the solvent extracts were oxygenated methoxybenzene derivatives such as 3,4,5‐trimethoxybenzyl alcohol (26.3%; 24.7%), methyl syringate (23.8%; 11.7%), and 3,4‐dimethoxybenzyl alcohol (5.6%; 13.9%). Another group of abundant compounds in the extracts were derivatives of linalool (e.g., (E)/(Z)‐2,6‐dimethylocta‐2,7‐diene‐1,6‐diol (17.8%; 16.1%)). Among the compounds identified, cis/trans‐anhydrolinalool oxides and 3,4,5‐trimethoxybenzyl alcohol can be useful as chemical markers of coriander honey.
Biological Activities of Phenolic Compounds and Triterpenoids from the Galls of Terminalia chebula
Authors: Manosroi Aranya , Jantrawut Pensak , Ogihara Eri , Yamamoto Ayako , Fukatsu Makoto , Yasukawa Ken , Tokuda Harukuni , Suzuki Nobutaka , Manosroi Jiradej , Akihisa Toshihiro 
Published: August 2013

AbstractNine phenolic compounds, including two phenolic carboxylic acids, 1 and 2, seven hydrolyzable tannins, 3–9, eight triterpenoids, including four oleanane‐type triterpene acids, 10–13, and four of their glucosides, 14–17, isolated from a MeOH extract of the gall of Terminalia chebula Retz. (myrobalan tree; Combretaceae), were evaluated for their inhibitory activities against melanogenesis in B16 melanoma cells induced by α‐melanocyte‐stimulating hormone (α‐MSH), against the EpsteinBarr virus early antigen (EBV‐EA) activation induced by 12‐O‐tetradecanoylphorbol 13‐acetate (TPA) in Raji cells, and against TPA‐induced inflammation in mice. Their 1,1‐diphenyl‐2‐picrylhydrazyl (DPPH) radical‐scavenging activities and cytotoxic activities against four human cancer cell lines were also evaluated. Compounds 6–9 and 12 exhibited potent inhibitory activities against melanogenesis (39.3–66.3% melanin content) with low toxicity to the cells (74.5–105.9% cell viability) at a concentration of 10 μM. Western‐blot analysis revealed that isoterchebulin (8) reduced the protein levels of MITF (=microphtalmia‐associated transcription factor), tyrosinase, and TRP‐1 (=tyrosine‐related protein 1), mostly in a concentration‐dependent manner. Eight triterpenoids, 10–17, showed potent inhibitory effects on EBV‐EA induction with the IC50 values in the range of 269–363 mol ratio/32 pmol TPA, while these compounds exhibited no DPPH scavenging activities (IC50>100 μM). On the other hand, the nine phenolic compounds, 1–9, exhibited potent radical‐scavenging activities (IC50 1.4–10.9 μM) with weak inhibitory effects on EBV‐EA induction (IC50 460–518 mol ratio/32 pmol TPA). The tannin 6 and seven triterpenoids, 10–16, have been shown to inhibit TPA‐induced inflammation (1 μg/ear) in mice with the ID50 values in the range of 0.06–0.33 μmol/ear. Arjungenin (10) exhibited inhibitory effect on skin‐tumor promotion in an in vivo two‐stage mouse‐skin carcinogenesis test based on 7,12‐dimethylbenz[a]anthracene (DMBA) as initiator and with TPA as promoter. Compounds 1, 2, 4, 5, 7–9, 12, and 13, against HL60 cell line, compounds 1 and 4, against AZ521 cell line, and compounds 1, 11, and 12, against SK‐BR‐3 cell line, showed moderate cytotoxic activities (IC50 13.9–73.2 μM).
Heparin Modulates the Mitogenic Activity of Fibroblast Growth Factor by Inducing Dimerization of its Receptor. A 3D View by Using NMR
Authors: Nieto Lidia , Canales Ángeles , Fernández Israel S. , Santillana Elena , González‐Corrochano Rocío , Redondo‐Horcajo Mariano , Cañada F. Javier , Nieto Pedro , Martín‐Lomas Manuel , Giménez‐Gallego Guillermo , Jiménez‐Barbero Jesús 
Published: August 2013

AbstractIn vitro mitogenesis assays have shown that sulfated glycosaminoglycans (GAGs; heparin and heparan sulfate) cause an enhancement of the mitogenic activity of fibroblast growth factors (FGFs). Herein, we report that the simultaneous presence of FGF and the GAG is not an essential requisite for this event to take place. Indeed, preincubation with heparin (just before FGF addition) of cells lacking heparan sulfate produced an enhancing effect equivalent to that observed when the GAG and the protein are simultaneously added. A first structural characterization of this effect by analytical ultracentrifugation of a soluble preparation of the heparin‐binding domain of fibroblast growth factor receptor 2 (FGFR2) and a low molecular weight (3 kDa) heparin showed that the GAG induces dimerization of FGFR2. To derive a high resolution structural picture of this molecular recognition process, the interactions of a soluble heparin‐binding domain of FGFR2 with two different homogeneous, synthetic, and mitogenically active sulfated GAGs were analyzed by NMR spectroscopy. These studies, assisted by docking protocols and molecular dynamics simulations, have demonstrated that the interactions of these GAGs with the soluble heparin‐binding domain of FGFR induces formation of an FGFR dimer; its architecture is equivalent to that in one of the two distinct crystallographic structures of FGFR in complex with both heparin and FGF1. This preformation of the FGFR dimer (with similar topology to that of the signaling complex) should favor incorporation of the FGF component to form the final assemblage of the signaling complex, without major entropy penalty. This cascade of events is probably at the heart of the observed activating effect of heparin in FGF‐driven mitogenesis.
Beta Sheets with a Twist: The Conformation of Helical Polyisocyanopeptides Determined by Using Vibrational Circular Dichroism
Authors: Schwartz Erik , Liégeois Vincent , Koepf Matthieu , Bodis Pavol , Cornelissen Jeroen J. L. M. , Brocorens Patrick , Beljonne David , Nolte Roeland J. M. , Rowan Alan E. , Woutersen Sander , Champagne Benoît 
Published: August 2013

AbstractDetailed information on the architecture of polyisocyanopeptides based on vibrational circular dichroism (VCD) spectroscopy in combination with DFT calculations is presented. It is demonstrated that the screw sense of the helical polyisocyanides can be determined directly from the CN‐stretch vibrational region of the VCD spectrum. Analysis of the VCD signals associated with the amide I and amide II modes provides detailed information on the peptide side‐chain arrangement in the polymer and indicates the presence of a helical β‐sheet architecture, in which the dihedral angles are slightly different to those of natural β‐sheet helices.
Determination of Enantioselectivity and Enantiomeric Excess by Mass Spectrometry in the Absence of Chiral Chromatographic Separation: An Overview
Authors: Piovesana Susy , Samperi Roberto , Laganà Aldo , Bella Marco 
Published: August 2013

AbstractThis review describes the principles and instrumentation for the screening of asymmetric reactions by mass spectrometry. These techniques witnessed a significant advancement in the last few years. Although some of them are still at the proof‐of‐concept development stage, several applications might be foreseen in the field of combinatorial, high‐throughput parallel catalyst screening.
α‐Oligofurans: A Computational Study
Authors: Sharma Sagar , Bendikov Michael 
Published: August 2013

AbstractRecently, α‐oligofurans have emerged as interesting and promising organic electronic materials that have certain advantages over α‐oligothiophenes. In this work, α‐oligofurans were studied computationally, and their properties were compared systematically with those of the corresponding oligothiophenes. Although the two materials share similar electronic structures, overall, this study revealed important differences between α‐oligofurans and α‐oligothiophenes. Twisting studies on oligofurans revealed them to be significantly more rigid than oligothiophenes in the ground state and first excited state. Neutral α‐oligofurans have more quinoid character, higher frontier orbital energies, and higher HOMO–LUMO gaps than their α‐oligothiophene counterparts. The theoretical results suggest that oligofurans (and subsequently polyfuran) have lower ionization potentials than the corresponding oligothiophenes (and polythiophene), which in turn predicts that oligofurans can be lightly doped more easily than oligothiophenes. Oligofuran dications (8 F2+–14 F2+) of medium‐sized and longer chain lengths show a polaron‐pair character, and the polycations of α‐oligofurans cannot accommodate high positive charges as easily as their thiophene analogues.
Towards Molecular Ribbons of Corannulene
Authors: Furrer Fabienne , Linden Anthony , Stuparu Mihaiela C. 
Published: August 2013

AbstractHerein, we explore the synthesis of corannulene‐based ribbon‐shaped molecules through a repetitive Diels–Alder strategy. For this, appropriate corannulene‐based dienes and dienophiles were identified and synthesized. These building blocks could be combined in a modular way to obtain the dimeric and trimeric segments of the hypothetical molecular ribbons. 1D and 2D NMR measurements, along with crystal‐structure analyses, allowed the structures and geometries of the synthesized compounds to be determined.
Regioselectivity and Competition of the Paternò–Büchi Reaction and Triplet–Triplet Energy Transfer between Triplet Benzophenones and Pyrimidines: Control by Triplet Energy Levels
Authors: Liu Xiu‐Ling , Wang Jian‐Bo , Tong Yao , Song Qin‐Hua 
Published: August 2013

AbstractThe photochemical reaction of a pyrimidine and a ketone occurs either as a Paternò–Büchi (PB) reaction or as energy transfer (ET) from the triplet ketone to the pyrimidine. It is rare for the two types of reactions to occur concurrently, and their competitive mechanism remains unknown. In this work, two classes of products, regioisomeric oxetane(s) (2, 3) from a PB reaction and three isomeric dimers of 5‐fluoro‐1,3‐dimethyl uracil (FDMU) (4–6) from a photosensitized dimerization of FDMU, are obtained through the UV irradiation of FDMU with various benzophenones (BPs). The ratio of the two products (oxetanes to dimers) reveals that the two competitive reactions depend strongly on the triplet energy levels (ET) of the BPs. The BPs with higher ET values lead to higher proportions of dimers, whereas those with lower ET values give higher proportions of oxetane(s), with the generation of just two regioisomeric oxetanes for the BP with the lowest ET of the eight BPs investigated. The ratio of the two oxetanes (2:3) decreases with the BP ET value. The competitive mechanism for the two types of photochemical reactions is demonstrated through quenching experiments and investigation of temperature effects. Kinetic analysis shows that the rate constants of the two [2+2] photocycloadditions are comparable. Furthermore, in combination with the results of previous studies, we have gained insight into the dependence of the photochemical type and the regioselectivity in the PB reaction on the triplet energy gaps (ΔE) between the pyrimidines and ketones. For ketones with higher ET values than the pyrimidines, the photochemical reaction is a photosensitized dimerization of the pyrimidine. In the opposite case, a PB reaction occurs, and the lower the ET of the ketones, the lower the ratio of oxetanes (2:3). When the ET of values of the ketones are close to those of the pyrimidines, the two reactions occur concurrently, and the higher the ET of the ketones, the higher the proportion of the dimers. The ratio of oxetanes (2:3) decreases with the ET value of the BPs.
Watching Orientational Ordering at the Nanoscale with Coherent Anti‐Stokes Raman Microscopy
Authors: Parekh Sapun H. , Domke Katrin F. 
Published: August 2013

AbstractWhether in lipid membranes, liquid crystals or solid‐state catalysts, the orientational ordering of molecules greatly influences the overall system behaviour. However, watching molecular alignment is a huge technical challenge. This article introduces nonlinear Raman (coherent anti‐Stokes Raman scattering; CARS) microscopy as a promising tool for fast, label‐free 3D chemical and structural sample characterization at the nanoscale in real time.
Organocatalytic Triazole Formation, Followed by Oxidative Aromatization: Regioselective Metal‐Free Synthesis of Benzotriazoles
Authors: Ramachary Dhevalapally B. , Shashank Adluri B. 
Published: August 2013

AbstractHerein we report on our studies on the sequential one‐pot combinations of amine‐catalyzed multicomponent reactions (MCRs). We have developed the copper‐free synthesis of functionalized bicyclic N‐aryl‐1,2,3‐triazole and N‐arylbenzotriazole products 4 and 5 from the simple unmodified starting materials through [3+2]‐cycloaddition ([3+2]‐CA) and oxidative aromatization reactions in one pot under amine catalysis. The sequential one‐pot reaction proceeds in good yields with high selectivity by using pyrrolidine as the catalyst from the simple unmodified substrates of enones, aryl azides, and 2,3‐dichloro‐5,6‐dicyano‐1,4‐benzoquinone (DDQ). Furthermore, we have demonstrated the medicinal applications of products 4 and 5 through simple organic reactions.
Mesoporous Core–Shell Fenton Nanocatalyst: A Mild, Operationally Simple Approach to the Synthesis of Adipic Acid
Authors: Patra Astam K. , Dutta Arghya , Bhaumik Asim 
Published: August 2013

AbstractMesoporous nanoparticles composed of γ‐Al2O3 cores and α‐Fe2O3 shells were synthesized in aqueous medium. The surface charge of γ‐Al2O3 helps to form the core–shell nanocrystals. The core–shell structure and formation mechanism have been investigated by wide‐angle XRD, energy‐dispersive X‐ray spectroscopy, and elemental mapping by ultrahigh‐resolution (UHR) TEM and X‐ray photoelectron spectroscopy. The N2 adsorption–desorption isotherm of this core–shell materials, which is of type IV, is characteristic of a mesoporous material having a BET surface area of 385 m2 g−1 and an average pore size of about 3.2 nm. The SEM images revealed that the mesoporosity in this core–shell material is due to self‐aggregation of tiny spherical nanocrystals with sizes of about 15–20 nm. Diffuse‐reflectance UV/Vis spectra, elemental mapping by UHRTEM, and wide‐angle XRD patterns indicate that the materials are composed of aluminum oxide cores and iron oxide shells. These Al2O3@Fe2O3 core–shell nanoparticles act as a heterogeneous Fenton nanocatalyst in the presence of hydrogen peroxide, and show high catalytic efficiency for the one‐pot conversion of cyclohexanone to adipic acid in water. The heterogeneous nature of the catalyst was confirmed by a hot filtration test and analysis of the reaction mixture by atomic absorption spectroscopy. The kinetics of the reaction was monitored by gas chromatography and 1H NMR spectroscopy. The new core–shell catalyst remained in a separate solid phase, which could easily be removed from the reaction mixture by simple filtration and the catalyst reused efficiently.