bluuebunny/crossref_metadata_2025_split huggingface dataset:
Four Ardeemin Analogs from Endophytic Aspergillus fumigatus SPS‐02 and Their Reversal Effects on Multidrug‐Resistant Tumor Cells
Authors: Zhang Hua‐Wei , Ying Chen , Tang Yi‐Fei 
Published: January 2014

AbstractFour ardeemin derivatives, 5‐N‐acetylardeemin (1), 5‐N‐acetyl‐15bβ‐hydroxyardeemin (2), 5‐N‐acetyl‐15b‐didehydroardeemin (3), and 5‐N‐acetyl‐16α‐hydroxyardeemin (4), were isolated from the fermentation broth of an endophytic Aspergillus fumigatus SPS‐02 associated with Artemisia annua L. The structures of these metabolites were elucidated by a combination of spectroscopic data, including 1D‐, 2D‐NMR and MS. In vitro chemosensitization assay indicated that these ardeemins had different activities of reversing the multidrug‐resistant (MDR) phenotype in three cancer cell lines, leukemia doxorubicin resistant cell K562/DOX, human lung adenocarcinoma cis‐platin‐resistant cell A549/DDP, and ovarian cancer cisplatin‐resistant cell SK‐OV‐S/DDP. Compound 4 exhibited the strongest MDR reversing effect at 5 μM concentration in K562/DOX and A549/DDP cell lines 5.2±0.18‐fold, 8.2±0.23‐fold, respectively, while compound 2 had the highest reversal capacity in SK‐OV‐S/DDP cell line with 10.8±0.28 fold. Preliminary investigation of their structureactivity relationship suggested that a OH group at C(15b) or C(16) in ardeemin plays a key role in reversing the MDR effect. It is the first report on ardeemin analogs from endophytic A. fumigatus with reversal effects on MDR cancer cell lines K562/DOX, A549/DDP and SK‐OV‐S/DDP.
In vitro Biological Activities of Seed Essential Oils from the Cameroonian Spices Afrostyrax lepidophyllusMildbr. and Scorodophloeus zenkeriHarms Rich in Sulfur‐Containing Compounds
Authors: Fogang Hervet P. D. , Maggi Filippo , Tapondjou Léon A. , Womeni Hilaire M. , Papa Fabrizio , Quassinti Luana , Bramucci Massimo , Vitali Luca A. , Petrelli Dezemona , Lupidi Giulio , Vittori Sauro , Barboni Luciano 
Published: January 2014

AbstractThe chemical composition of the essential oils obtained from the seeds of bush onion (Afrostyrax lepidophyllus) and tropical garlic tree (Scorodophloeus zenkeri), plants used as spices in the traditional African cuisine, was determined by GC‐FID and GC/MS analyses. Moreover, in vitro biological properties of the oils, namely, the cytotoxic, antioxidant, and antimicrobial activities, were investigated by the MTT, the DPPH. and ABTS.+ scavenging, and the agar disc‐diffusion methods, respectively. Both oils were composed mainly by S‐containing compounds, accounting for 91.0–96.1% of the total oil compositions, which provided them the typical garlic‐ and onion‐like odors of spices. The predominant compound in both oils, 2,4,5,7‐tetrathiaoctane (1; 51.5–52.9%), was isolated by preparative TLC and structurally elucidated by 1H‐ and 13C‐NMR data. The oils exhibited a strong inhibitory effect on the growth of human cancer cells, namely, T98G (human glioblastoma multiforme cell line), MDA‐MB 231 (human breast adenocarcinoma cell line), A375 (human malignant melanoma cell line), and HCT116 (human colon carcinoma cell line) cells, and a good DPPH.‐ and ABTS.+‐scavenging activity, while the antimicrobial effects were negligible. The volatile compositions of A. lepidophyllus and S. zenkeri oils supported their use as odorous spices. The significant inhibition activities detected make these oils worthy of further investigation as promising chemopreventive agents to be exploited in the African pharmaceutical market.
Tailoring Biomass‐Derived Carbon Nanoarchitectures for High‐Performance Supercapacitors
Authors: Wang Huanlei , Li Zhi , Mitlin David 
Published: January 2014

AbstractInvited for this month’s cover is Prof. Dave Mitlin′s group at the University of Alberta and NINT NRC. The image highlights the amazing potential for sustainably transforming a range of “waste” biomass precursors into truly value‐added energy‐storage carbons, some being akin to graphene in both structure and electrochemical properties.	Read the full text of the article at 10.1002/celc.201300127.
Is Electrostatics Sufficient to Describe Hydrogen‐Bonding Interactions?
Authors: Hoja Johannes , Sax Alexander F. , Szalewicz Krzysztof 
Published: January 2014

AbstractThe stability and geometry of a hydrogen‐bonded dimer is traditionally attributed mainly to the central moiety AH⋅⋅⋅B, and is often discussed only in terms of electrostatic interactions. The influence of substituents and of interactions other than electrostatic ones on the stability and geometry of hydrogen‐bonded complexes has seldom been addressed. An analysis of the interaction energy in the water dimer and several alcohol dimers—performed in the present work by using symmetry‐adapted perturbation theory—shows that the size and shape of substituents strongly influence the stabilization of hydrogen‐bonded complexes. The larger and bulkier the substituents are, the more important the attractive dispersion interaction is, which eventually becomes of the same magnitude as the total stabilization energy. Electrostatics alone are a poor predictor of the hydrogen‐bond stability trends in the sequence of dimers investigated, and in fact, dispersion interactions predict these trends better.
Copper‐Promoted Oxidative Coupling of Enamides and Alkynes for the Synthesis of Substituted Pyrroles
Authors: Zhao Mi‐Na , Ren Zhi‐Hui , Wang Yao‐Yu , Guan Zheng‐Hui 
Published: January 2014

AbstractAn efficient copper‐promoted oxidative coupling of enamides with alkynes has been developed for the synthesis of substituted pyrroles. The reaction proceeded through CH and NH bond functionalization of enamides under mild conditions.
Optimization of Easy‐to‐Clean Composite Coatings Using Hydrophobic Nanoparticles
Authors: Barth Nina , Hesselbach Jutta , Schilde Carsten , Kwade Arno 
Published: January 2014

AbstractIn vielen Bereichen können durch den Einsatz von Nanopartikeln die anwendungstechnischen Eigenschaften von Kompositbeschichtungen maßgeblich verändert werden. So können in Abhängigkeit von Partikelgrößenverteilung und Feststoffgehalt Eigenschaften wie Reinigbarkeit, Härte und Rauheit deutlich beeinflusst werden. So eignen sich beispielsweise kleinere Partikelgrößen und höhere Feststoffgehalte hydrophober Nanopartikel zur Erhöhung des Kontaktwinkels.
Vom Münchner Olympiastadion zur Entropieelastizität
Authors: Heller Cathrin , Busker Maike 
Published: January 2014

AbstractPlexiglas® ist ein häufig verwendeter Kunststoff, der aufgrund seiner Lichtdurchlässigkeit und Bruchsicherheit unter anderem als Glasersatz große Verwendung findet. Hinter dem Namen Plexiglas® verbirgt sich das Polymer Polymethylmethacrylat (PMMA). Zugänglich ist dieses durch radikalische Polymerisation von Methylmethacrylat. In diesem Beitrag wird die Herstellung von Plexiglas®‐Scheiben innerhalb der schulischen Möglichkeiten vorgestellt und es werden Experimente rund um die Eigenschaften von Plexiglas beschrieben.
Discovery of Heterocyclic Nonacetamide Synaptic Vesicle Protein 2A (SV2A) Ligands with Single‐Digit Nanomolar Potency: Opening Avenues towards the First SV2A Positron Emission Tomography (PET) Ligands
Authors: Mercier Joël , Archen Laurence , Bollu Véronique , Carré Stéphane , Evrard Yves , Jnoff Eric , Kenda Benoît , Lallemand Bénédicte , Michel Philippe , Montel Florian , Moureau Florence , Price Nathalie , Quesnel Yannick , Sauvage Xavier , Valade Anne , Provins Laurent 
Published: January 2014

AbstractThe role of the synaptic vesicle protein 2A (SV2A) protein, target of the antiepileptic drug levetiracetam, is still mostly unknown. Considering its potential to provide in vivo functional insights into the role of SV2A in epileptic patients, the development of an SV2A positron emission tomography (PET) tracer has been undertaken. Using a 3D pharmacophore model based on close analogues of levetiracetam, we report the rationale design of three heterocyclic non‐acetamide lead compounds, UCB‐A, UCB‐H and UCB‐J, the first single‐digit nanomolar SV2A ligands with suitable properties for development as PET tracers.
Timing is everything: priority effects alter community invasibility after disturbance
Authors: Symons Celia C. , Arnott Shelley E. 
Published: January 2014

AbstractTheory suggests that communities should be more open to the establishment of regional species following disturbance because disturbance may make more resources available to dispersers. However, after an initial period of high invasibility, growth of the resident community may lead to the monopolization of local resources and decreased probability of successful colonist establishment. During press disturbances (i.e., directional environmental change), it remains unclear what effect regional dispersal will have on local community structure if the establishment of later arriving species is affected by early arriving species (i.e., if priority effects are important). To determine the relationship between time‐since‐disturbance and invasibility, we conducted a fully factorial field mesocosm experiment that exposed tundra zooplankton communities to two emerging stressors – nutrient and salt addition, and manipulated the arrival timing of regional dispersers. Our results demonstrate that invasibility decreases with increasing time‐since‐disturbance as abundance (nutrient treatments) or species richness (salt treatments) increases in the resident community. Results suggest that the relative timing of dispersal and environmental change will modify the importance of priority effects in determining species composition after a press disturbance.
A novel link allocation method for vehicle‐to‐vehicle‐based relaying networks
Authors: Zheng Qiang , Zheng Kan , Chatzimisios Periklis , Long Hang , Liu Fei 
Published: January 2014

AbstractVehicle‐to‐infrastructure (V2I) and vehicle‐to‐vehicle (V2V) are two main communication modes in vehicular ad‐hoc networks. V2V is one of the key techniques to enhance the coverage and capacity of the V2I communication system. In this paper, we propose a novel link allocation method involving both V2I and V2V communications to enhance the throughput of the V2V‐based relaying network. Jointing the links scheduling and radio resource allocation to V2V links is an Non‐deterministic Polynomial (NP) hard problem with huge complexity. The proposed scheduling scheme adopts a dynamic optimization algorithm based on the multi‐choice knapsack problem to solve the problem with acceptable complexity. Simulation results demonstrate that the proposed scheme significantly improves throughput of vehicular networks and achieves higher fairness. Copyright © 2014 John Wiley & Sons, Ltd.
Performance analysis of optical CDMA communication systems with M‐ary PWM signalling
Authors: Wu Wei‐Chiang , Hsu Chieh‐Yen 
Published: January 2014

ABSTRACTIn this paper, a novel M‐ary pulse‐width modulation (PWM) coded optical code division multiple access (O‐CDMA) system is proposed. At the transmitter end, in order to increase the number of transmitted bits per pulse, each chip of signature sequence is further divided into M time slots to realise the M‐ary PWM signal format. Two types of detection schemes are developed, and the performance in terms of symbol error rate is analysed. In the first scheme, the correlation receiver is employed followed by an M‐level threshold detection. To enhance the multiuser interference suppression capability, we apply the chip‐level‐based diversity detection in the second scheme. Adding optical hard‐limiters at the front end of the receiver, both schemes are free from the near–far problem that is suffered severely in O‐CDMA system employing pulse‐amplitude modulation (PAM). Numerical results demonstrate that the proposed M‐ary PWM O‐CDMA system with the chip‐level receiver achieves better symbol error rate and multiuser interference mitigation capability than the correlation receiver. Moreover, the performance of the proposed M‐ary PWM O‐CDMA system is much better than the M‐ary pulse‐amplitude modulation scheme. And the complexity is substantially reduced as we compare to the existing M‐ary pulse‐position modulation O‐CDMA system. Copyright © 2014 John Wiley & Sons, Ltd.
Domestication, phylogeny and taxonomic delimitation in underutilized grain Amaranthus (Amaranthaceae) – a status review
Authors: Das Saubhik 
Published: January 2014

AbstractMany neglected, underutilized species are extremely important for food production especially in Low Income Food Deficient Countries (LIFDCs). Grain amaranth is one of such crops originated and domesticated in different parts of American continent. Lack of knowledge on taxonomy and phylogenetic relationship with other related crops, analysis of the extent and distribution of genetic diversity together with work on local and traditional knowledge, are the main constrains for genetic improvement of neglected, underutilized and crop related wild species. The phylogenetic relationship and taxonomic delimitation in genus Amaranthus are still not resolved with extreme clarity. But classification of the genus Amaranthus into three subgenera viz., Acnida, Amaranthus and Albersia, based on morphological parameters is quite acceptable. Phylogenetic analysis revealed clear separation of vegetable and grain amaranths. The derivation of grain and vegetable amaranths represent two lines of descent from weed progenitor. Amaranthus hybridus L. along with grain amaranths supposed to have formed a complex in which taxonomic problems are far from being clarified, especially because of apparent common hybridization and misapplication of nomenclature. (© 2014 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Chemical and functional properties of cassava starch, durum wheat semolina flour, and their blends
Authors: Oladunmoye Olufunmilola O. , Aworh Ogugua C. , Maziya‐Dixon Bussie , Erukainure Ochuko L. , Elemo Gloria N. 
Published: January 2014

AbstractHigh‐quality cassava starch (HQCS) produced from high‐yielding low‐cyanide improved cassava variety, TMS 30572, was mixed with durum wheat semolina (DWS) on a replacement basis to produce flour samples containing 0, 20, 30, 50, 70, and 100% cassava starch. They were analyzed for chemical composition (proximate, amylose, free sugars, starch, wet gluten, and cyanide) and functional properties (pasting, swelling power, solubility, water absorption, water binding, starch damage, diastatic and α‐amylase activity, dough mixing, and stability). Protein, carbohydrate, fat, and ash of flour samples ranged from 0.75–12.31%, 70.87–87.80%, 0.95–4.41%, and 0.12–0.83%, respectively. Cyanide levels in all the flour samples were less than 0.1 ppm. Amylose content varied between 19.49% for cassava and 28.19% for wheat, correlating significantly with protein (r = 0.95, P = 0.004) and ash contents (r = 0.92, P = 0.01) at 5%. DWS and HQCS had similar pasting temperatures (50.2–53°C), while other pasting properties increased with increasing levels of HQCS. Dough mixing stability of samples decreased with increasing levels of HQCS. All the flour samples had α‐amylase activity greater than 200. Both HQCS and DWS compare favorably well in swelling power (7.80–9.01%); but the solubility of wheat starch doubled that of cassava. Starch damage varied between 3.3 and 7.2 AACC for semolina and starch, with the latter having higher absorption rate (97%), and the former, higher absorption speed (67 sec). Results obtained showed positive insight into cassava–wheat blend characteristics. Data thus generated provide additional opportunities of exploiting cassava utilization and hence boost its value–addition potentials for product development.
Limiting the risk inherent to geological CO2 storage: The importance of predicting inorganic and organic chemical species behavior under supercritical CO2 fluid conditions
Authors: Zuddas Pierpaolo , Rillard Jean , Charoenjit Kitsanai , Toulhoat Pierre 
Published: January 2014

AbstractField tests have clearly demonstrated that injecting CO2 in geological storage sites results in the release of heavy metals and organic species to groundwater, implying that CO2 injection may have potentially dramatic consequences for the environment. Numerous laboratory experiments using rock and cement samples from different geological formations typical of injection sites show that rocks reacting with synthetic or natural fluids and supercritical CO2 at their respective temperature and pressure conditions generate fluids with As, Cr, Cu, Cd, Pb, Fe, and Mn concentrations above Environmental Protection Agency drinking water standards. The solubility of a compound in supercritical‐CO2 (sc‐CO2), expressed in terms of the compound's activity or fugacity, also depends on the composition of the phases present at the pressure and temperature of the storage site. In a brine sc‐CO2 system, estimating the activity of an inorganic compound or the fugacity of an organic compound is a prerequisite to predicting the solubility of a compound in sc‐CO2 phases. Available models (e.g. Pitzer equations) require the use of binary salt concentrations and are best applicable to polar ionic compounds; but the effect of brines on larger hydrocarbons has not yet been explored. New experimental data will be needed to determine the magnitude of pH effects on the partitioning behavior of organic acids and trace metal complexes from brine to sc‐CO2.
Prefrontal transcranial direct current stimulation alters activation and connectivity in cortical and subcortical reward systems: A tDCS‐fMRI study
Authors: Weber Matthew J. , Messing Samuel B. , Rao Hengyi , Detre John A. , Thompson‐Schill Sharon L. 
Published: January 2014

AbstractTranscranial direct current stimulation (tDCS) is a noninvasive brain stimulation technique used both experimentally and therapeutically to modulate regional brain function. However, few studies have directly measured the aftereffects of tDCS on brain activity or examined changes in task‐related brain activity consequent to prefrontal tDCS. To investigate the neural effects of tDCS, we collected fMRI data from 22 human subjects, both at rest and while performing the Balloon Analog Risk Task (BART), before and after true or sham transcranial direct current stimulation. TDCS decreased resting blood perfusion in orbitofrontal cortex and the right caudate and increased task‐related activity in the right dorsolateral prefrontal cortex (DLPFC) and anterior cingulate cortex (ACC) in response to losses but not wins or increasing risk. Network analysis showed that whole‐brain connectivity of the right ACC correlated positively with the number of pumps subjects were willing to make on the BART, and that tDCS reduced connectivity between the right ACC and the rest of the brain. Whole‐brain connectivity of the right DLPFC also correlated negatively with pumps on the BART, as prior literature would suggest. Our results suggest that tDCS can alter activation and connectivity in regions distal to the electrodes. Hum Brain Mapp 35:3673–3686, 2014. © 2014 Wiley Periodicals, Inc.
Common and dissociated mechanisms for estimating large and small dot arrays: Value‐specific fMRI adaptation
Authors: Demeyere Nele , Rotshtein Pia , Humphreys Glyn W. 
Published: January 2014

AbstractAn fMRI pair‐adaptation paradigm was used to identify the brain regions linked to the apprehension of small and large numbers of items. Participants classified stimuli on the basis of their numerosities (fewer or more than five dots). We manipulated the type of repetition within pairs of dot arrays. Overall processing of pairs with small as opposed to large quantities was associated with a decreased BOLD response in the midline structures and inferior parietal cortex. The opposite pattern was observed in middle cingulate cortex. Pairs in which the same numerosity category was repeated, were associated with a decreased signal in the left prefrontal and the left inferior parietal cortices, compared with when numerosities changed. Repetitions of exact numerosities irrespective of sample size were associated with decreased responses in bi‐lateral prefrontal, sensory‐motor regions, posterior occipital and left intraparietal sulcus (IPS). More importantly, we found value‐specific adaptation specific to repeated small quantity in the left lateral occipito‐temporal cortex, irrespective of whether the exact same stimulus pattern repeated. Our results indicate that a large network of regions (including the IPS) support visual quantity processing independent of the number of items present; however assimilation of small quantities is associated with additional support from regions within the left occipito‐temporal cortex. We propose that processing of small quantities is aided by a subitizing‐specific network. This network may account for the increased processing efficiency often reported for numerosities in the subitizing range. Hum Brain Mapp 35:3988–4001, 2014. © 2014 Wiley Periodicals, Inc.
Prediction of human actions: Expertise and task‐related effects on neural activation of the action observation network
Authors: Balser Nils , Lorey Britta , Pilgramm Sebastian , Stark Rudolf , Bischoff Matthias , Zentgraf Karen , Williams Andrew Mark , Munzert Jörn 
Published: January 2014

AbstractThe action observation network (AON) is supposed to play a crucial role when athletes anticipate the effect of others' actions in sports such as tennis. We used functional magnetic resonance imaging to explore whether motor expertise leads to a differential activation pattern within the AON during effect anticipation and whether spatial and motor anticipation tasks are associated with a differential activation pattern within the AON depending on participant expertise level. Expert (N = 16) and novice (N = 16) tennis players observed video clips depicting forehand strokes with the instruction to either indicate the predicted direction of ball flight (spatial anticipation) or to decide on an appropriate response to the observed action (motor anticipation). The experts performed better than novices on both tennis anticipation tasks, with the experts showing stronger neural activation in areas of the AON, namely, the superior parietal lobe, the intraparietal sulcus, the inferior frontal gyrus, and the cerebellum. When novices were contrasted with experts, motor anticipation resulted in stronger activation of the ventral premotor cortex, the supplementary motor area, and the superior parietal lobe than spatial anticipation task did. In experts, the comparison of motor and spatial anticipation revealed no increased activation. We suggest that the stronger activation of areas in the AON during the anticipation of action effects in experts reflects their use of the more fine‐tuned motor representations they have acquired and improved during years of training. Furthermore, results suggest that the neural processing of different anticipation tasks depends on the expertise level. Hum Brain Mapp 35:4016–4034, 2014. © 2014 Wiley Periodicals, Inc.