bluuebunny/crossref_metadata_2025 huggingface dataset:
Oral health of the Paleoamericans of Lagoa Santa, central Brazil
Authors: Da‐Gloria Pedro , Larsen Clark Spencer
Published: January 2014

The peopling, origins, and early prehistory of the Americas are topics of intense debate. However, few studies have used human remains to document and interpret patterns of health and lifestyle of Paleoamericans. This study provides the first investigation to characterize oral health in a series of early Holocene skeletal remains from Lagoa Santa, Brazil, a locality containing the remains of some of the earliest inhabitants of South America (10,000–7,000 BP). The sample is composed of 949 teeth and 1925 alveoli from an estimated 113 individuals excavated from 17 archaeological sites located in the State of Minas Gerais. We compare dental caries and abscess prevalence at Lagoa Santa to a large sample of human skeletons from the Western Hemisphere Project (WHP) database using both individual and tooth/alveolus count methods. In addition, antemortem tooth loss and tooth wear were analyzed in Lagoa Santa by sex and age. The results show that Lagoa Santa dental caries and abscess prevalence are significantly higher than observed among other hunter–gatherers included in the WHP database, except when abscess prevalence is considered by individual count. Adult females have less tooth wear coupled with higher prevalence of dental caries and antemortem tooth loss than adult males. These results point to an unexpected record of poor oral health at Lagoa Santa, especially among females. A diet based on a highly cariogenic combination of wild tubers and fruits is suggested as an explanation for the elevated rate, characterizing an early adaptation to a tropical environment in South America. Am J Phys Anthropol 154:11–26, 2014. © 2014 Wiley Periodicals, Inc.
SpinPhox/Iridium(I)‐Catalyzed Asymmetric Hydrogenation of Cyclic α‐Alkylidene Carbonyl Compounds
Authors: Liu Xu , Han Zhaobin , Wang Zheng , Ding Kuiling
Published: January 2014

Optically active medium‐sized cyclic carbonyl compounds bearing an α‐chiral carbon center are of interest in pharmaceutical sciences and asymmetric synthesis. Herein, SpinPhox/IrI catalysts have been demonstrated to be highly enantioselective in the asymmetric hydrogenation of the CC bonds in the exocyclic α,β‐unsaturated cyclic carbonyls, including a broad range of α‐alkylidene lactams, unsaturated cyclic ketones, and lactones. It is noteworthy that the procedure can be successfully used in the asymmetric hydrogenation of the challenging α‐alkylidenelactam substrates with six‐ or seven‐membered rings, thus affording the corresponding optically active carbonyl compounds with an α‐chiral carbon center in generally excellent enantiomeric excesses (up to 98 % ee). Synthetic utility of the protocol has also been demonstrated in the asymmetric synthesis of the anti‐inflammatory drug loxoprofen and its analogue, as well as biologically important ε‐aminocaproic acid derivatives.
Pseudiline: halogenierte, allosterische Inhibitoren des Enzyms IspD aus dem Mevalonat‐unabhängigen Biosyntheseweg
Authors: Kunfermann Andrea , Witschel Matthias , Illarionov Boris , Martin René , Rottmann Matthias , Höffken H. Wolfgang , Seet Michael , Eisenreich Wolfgang , Knölker Hans‐Joachim , Fischer Markus , Bacher Adelbert , Groll Michael , Diederich François
Published: January 2014

Die Enzyme des Mevalonat‐unabhängigen Terpenbiosynthesewegs wurden als attraktive Zielstrukturen mit neuartigen Wirkmechanismen für die Entwicklung von Herbiziden zum Pflanzenschutz und Medikamente gegen Infektionskrankheiten identifiziert. Dieser Biosyntheseweg findet sich in vielen humanpathogenen Organismen und Pflanzen, kommt jedoch in Säugetieren nicht vor. Durch die Verwendung eines Hochdurchsatz‐Screening‐Verfahrens haben wir hochgradig halogenierte, marine Naturstoffe, die Pseudiline, als Inhibitoren gegen das dritte Enzym des Biosynthesewegs, IspD, entdeckt. Deren Aktivität gegen die IspD‐Enzyme aus Arabidopsis thaliana und Plasmodium vivax wurde in photometrischen und NMR‐basierten Assays bestimmt. Kokristallstrukturen zeigten, dass Pseudiline in einer allosterischen Tasche binden und dabei sowohl divalente Metallionen koordinieren, als auch Halogenbindungen ausbilden. Der allosterische Wirkmechanismus, der die Bindung des Kosubstrats (CTP) in der aktiven Tasche verhindert, wurde untersucht. Pseudiline zeigen herbizide Aktivität in Pflanzen‐Assays und antiplasmodiale Aktivität in zellbasierten Assays.
Biomimetic RNA‐Silencing Nanocomplexes: Overcoming Multidrug Resistance in Cancer Cells
Authors: Wang Zhongliang , Wang Zhe , Liu Dingbin , Yan Xuefeng , Wang Fu , Niu Gang , Yang Min , Chen Xiaoyuan
Published: January 2014

RNA interference (RNAi) is an RNA‐dependent gene silencing approach controlled by an RNA‐induced silencing complex (RISC). Herein, we present a synthetic RISC‐mimic nanocomplex, which can actively cleave its target RNA in a sequence‐specific manner. With high enzymatic stability and efficient self‐delivery to target cells, the designed nanocomplex can selectively and potently induce gene silencing without cytokine activation. These nanocomplexes, which target multidrug resistance, are not only able to bypass the P‐glycoprotein (Pgp) transporter, due to their nano‐size effect, but also effectively suppress Pgp expression, thus resulting in successful restoration of drug sensitivity of OVCAR8/ADR cells to Pgp‐transportable cytotoxic agents. This nanocomplex approach has the potential for both functional genomics and cancer therapy.
A Mass Spectrometric Approach for Probing the Stability of Bioorganic Radicals
Authors: Tan Lei , Hu Hanfeng , Francisco Joseph S. , Xia Yu
Published: January 2014

Glycyl radicals are important bioorganic radical species involved in enzymatic catalysis. Herein, we demonstrate that the stability of glycyl‐type radicals (X‐.CH‐Y) can be tuned on a molecular level by varying the X and Y substituents and experimentally probed by mass spectrometry. This approach is based on the gas‐phase dissociation of cysteine sulfinyl radical (X‐Cys‐Y) ions through homolysis of a CαCβ bond. This fragmentation produces a glycyl‐type radical upon losing CH2SO, and the degree of this loss is closely tied to the stability of the as‐formed radical. Theoretical calculations indicate that the energy of the CαCβ bond homolysis is predominantly affected by the stability of the glycyl radical product through the captodative effect, rather than that of the parent sulfinyl radical. This finding suggests a novel experimental method to probe the stability of bioorganic radicals, which can potentially broaden our understanding of these important reactive intermediates.
Peierls‐Distorted Monoclinic MnB4with a MnMn Bond
Authors: Knappschneider Arno , Litterscheid Christian , George Nathan C. , Brgoch Jakoah , Wagner Norbert , Beck Johannes , Kurzman Joshua A. , Seshadri Ram , Albert Barbara
Published: January 2014

Tetraborides of chromium and manganese exhibit an unusual boron‐atom framework that resembles the hypothetical tetragonal diamond. They are believed to be very hard. Single crystals of MnB4have now been grown. The compound crystallizes in the monoclinic crystal system (space groupP21/c) with a structure that has four crystallographically independent boron‐atom positions, as confirmed by11B MAS‐NMR spectroscopy. An unexpected short distance between the Mn atoms suggests a double Mn–Mn bond and is caused by Peierls distortion. The structure was solved using group‐subgroup‐relationships. DFT calculations indicate MnIcenters and paramagnetism, as confirmed by magnetic measurements. The density of states shows a pseudo‐band gap at the Fermi energy and semiconducting behavior was observed for MnB4.
The Existence of Hexafluoroarsenic(V) Acid
Authors: Axhausen Joachim , Lux Karin , Kornath Andreas
Published: January 2014

The homogeneous mixture of anhydrous hydrogen fluoride aHF and antimony pentafluoride AsF5 is known as a superacidic system. The high acidity is derived from the formation of [H2F]+ [AsF6]−. No experimental evidence exists for the existence of the free acid molecule HAsF6. The reaction of trimethylsilyl N,N‐dimethylcarbamate in the binary system aHF/AsF5 led to decomposition of trimethylsilyl N,N‐dimethylcarbamate at −50 °C to dimethylammonium hexafluoridoarsenate and cocrystallization of HAsF6. The single‐crystal X‐ray structure displays an HAsF6 molecule involved in an asymmetric hydrogen bridge to the hexafluoridoarsenate anion. As a result of the incalculable situation in the crystal lattice, the molecular structure of HAsF6 is calculated by quantum chemical structure optimization of the extreme cases of [FHF‐AsF5]− (strong hydrogen bond) and HAsF6 (no hydrogen bond) at the PBE1PBE/6‐311G(3df,3pd) level of theory.
Solvent‐Driven Chiral‐Interaction Reversion for Organogel Formation
Authors: Qing Guangyan , Shan Xingxing , Chen Wenrui , Lv Ziyu , Xiong Peng , Sun Taolei
Published: January 2014

For chiral gels and related applications, one of the critical issues is how to modulate the stereoselective interaction between the gel and the chiral guest precisely, as well as how to translate this information into the macroscopic properties of materials. Herein, we report that this process can also be modulated by nonchiral solvents, which can induce a chiral‐interaction reversion for organogel formation. This process could be observed through the clear difference in gelation speed and the morphology of the resulting self‐assembly. This chiral effect was successfully applied in the selective separation of quinine enantiomers and imparts “smart” merits to the gel materials.
Ambient Lithium–SO2 Batteries with Ionic Liquids as Electrolytes
Authors: Xing Huabin , Liao Chen , Yang Qiwei , Veith Gabriel M. , Guo Bingkun , Sun Xiao‐Guang , Ren Qilong , Hu Yong‐Sheng , Dai Sheng
Published: January 2014

Li‐SO2 batteries have a high energy density but bear serious safety problems that are associated with pressurized SO2 and flammable solvents in the system. Herein, a novel ambient Li‐SO2 battery was developed through the introduction of ionic liquid (IL) electrolytes with tailored basicities to solvate SO2 by reversible chemical absorption. By tuning the interactions of ILs with SO2, a high energy density and good discharge performance with operating voltages above 2.8 V were obtained. This strategy based on reversible chemical absorption of SO2 in IL electrolytes enables the development of the next generation of ambient Li‐SO2 batteries.
Selective synthesis of tricyclopentadiene from dicyclopentadiene with homogeneous Pd catalysts
Authors: Woo Jeong Oh , Park Jong‐Eun , Han JeongSik , Kwon Tae Soo , Kim Yeong‐Joon , Son Kyung‐sun
Published: January 2014

We explored a simple synthetic strategy with homogeneous palladium catalysts to afford a [2 + 2] isomer of tricyclopentadiene in good yield (up to 98% from cyclopentadiene and up to 78% from dicyclopentadiene) with high selectivity. The effects of a variety of palladium precursors, phosphorus ligands and acids were investigated to improve the productivity and selectivity of the tricyclopentadiene synthesis. The reaction conditions were evaluated and their effects on the product distribution were also discussed. Copyright © 2014 John Wiley & Sons, Ltd.
Pd nanoparticles immobilized on PNIPAM–halloysite: highly active and reusable catalyst for Suzuki–Miyaura coupling reactions in water
Authors: Hong Myeng Chan , Ahn Hyunseok , Choi Myung Chan , Lee Yongwoo , Kim Jongsik , Rhee Hakjune
Published: January 2014

Poly(N‐isopropylacrylamide)–halloysite (PNIPAM‐HNT) nanocomposites exhibited inverse temperature solubility with a lower critical solution temperature (LCST) in water. Palladium (Pd) nanoparticles were anchored on PNIPAM‐HNT nanocomposites with various amounts of HNT from 5 to 30 wt%. These Pd catalysts exhibited excellent reactivities for Suzuki–Miyaura coupling reactions at 50–70 °C in water. In particular, Pd anchored PNIPAM/HNT (95:5 w/w ratio) nanocomposites showed excellent recyclability up to 10 times in 96% average yield by simple filtration. Copyright © 2014 John Wiley & Sons, Ltd.
Valuable words: The price dynamics of internet domain names
Authors: Lindenthal Thies
Published: January 2014

This article estimates the first constant quality price index for Internet domain names. The suggested index provides a benchmark for domain name traders and investors looking for information on price trends, historical returns, and the fundamental risk of Internet domain names. The index increases transparency in the market for this newly emerged asset class. A cointegration analysis shows that domain registrations and resale prices form a long‐run equilibrium and indicates supply constraints in domain space. This study explores a large data set of domain sales spanning the years 2006 to 2013. Differences in the quality of individual domain names are controlled for in hedonic repeat sales regressions.
Coauthorship of journal articles and book chapters in the social sciences and humanities (2000–2010)
Authors: Ossenblok Truyken L.B. , Verleysen Frederik T. , Engels Tim C.E.
Published: January 2014

This study analyzes coauthorship patterns in the social sciences and humanities (SSH) for the period 2000 to 2010. The basis for the analysis is the Flemish Academic Bibliographic Database for the Social Sciences and Humanities (VABB‐SHW), a comprehensive bibliographic database of peer‐reviewed publications in the SSH by researchers affiliated with Flemish universities. Combining data on journal articles and book chapters, our findings indicate that collaborative publishing in the SSH is increasing, though considerable differences between disciplines remain. Conversely, we did observe a sharp decline in single‐author publishing. We further demonstrate that coauthored SSH articles in journals indexed in the Web of Science (WoS) generally have a higher (and growing) number of coauthors than do either those in non‐WoS journals or book chapters. This illustrates the need to include non‐WoS data and book chapters when studying coauthorship in the SSH.
Knowledge creation and the concept of a human being: A phenomenological approach
Authors: Suorsa Anna , Huotari Maija‐Leena
Published: January 2014

This study explores the effect of interaction in research on knowledge creation (KC) and its dependence on the conceptualization of a human being. A framework for understanding KC with hermeneutic phenomenology is developed, based on an analysis of recent KC research and key texts on hermeneutic phenomenology. The results obtained indicate that recent KC research still emphasizes the concept of knowledge as an asset inside the human mind, although the interest is in knowing and interpersonal relationships in working communities. Exploration of the use of the effect of interaction in research on KC shows that successful interaction is connected to the ideas of openness, critical thinking, and awareness of past experiences. These elements reflect the general ideas of the hermeneutic tradition without taking into account the historical roots of hermeneutics or questioning the concept of a human being behind them. It is concluded that the hermeneutic circle and phenomenological conceptualization of a human being provide a better defined and more coherent structure for understanding the event of KC as a future‐oriented, conscious act of interaction. The framework developed offers three fundamental areas for exploration: structure of the interactive event, construction of the human experience in interaction, and modes of being in interaction.
Adding Twitter‐specific features to stylistic features for classifying tweets by user type and number of retweets
Authors: Arakawa Yui , Kameda Akihiro , Aizawa Akiko , Suzuki Takafumi
Published: January 2014

Recently, Twitter has received much attention, both from the general public and researchers, as a new method of transmitting information. Among others, the number of retweets (RTs) and user types are the two important items of analysis for understanding the transmission of information on Twitter. To analyze this point, we applied text classification and feature extraction experiments using random forests machine learning with conventional stylistic and Twitter‐specific features. We first collected tweets from 40 accounts with a high number of followers and created tweet texts from 28,756 tweets. We then conducted 15 types of classification experiments using a variety of combinations of features such as function words, speech terms, Twitter's descriptive grammar, and information roles. We deliberately observed the effects of features for classification performance. The results indicated that class classification per user indicated the best performance. Furthermore, we observed that certain features had a greater impact on classification. In the case of the experiments that assessed the level of RT quantity, information roles had an impact. In the case of user experiments, important features, such as the honorific postpositional particle and auxiliary verbs, such as “desu” and “masu,” had an impact. This research clarifies the features that are useful for categorizing tweets according to the number of RTs and user types.
“All‐or‐None” Versus “Most‐or‐Some” Options in Risky Choice: Effects of Domain and Handedness
Authors: Christman Stephen D. , Jasper John D.
Published: January 2014

Two methodological variants of Kahneman and Tversky's Asian disease scenario were investigated. One variant involved replacing the “all‐or‐none” outcome scenarios of the risky choice with “most‐or‐some” scenario outcomes, and the second variant involved replacing the negative domain of lives lost with a positive domain of jobs created. In addition, the effects of strength of handedness, a variable related to individual differences in risk perception, were examined. Results indicated that standard framing effects were obtained across both domains, with a decrease in risky choice under the gain domain. Scenario type also interacted with handedness, such that the all‐or‐none scenario yielded framing effects for consistent (strong)‐handers only, whereas the most‐or‐some scenario yielded framing effects for inconsistent (mixed)‐handers only (consistent‐handers are those who use the same hand exclusively for almost all activities). These results demonstrate that framing effects are strongly influenced by the presence versus absence of extreme/absolute outcomes and that individuals (in this case, decision makers with varying degrees of handedness strength) are differentially sensitive to different pieces of information. Copyright © 2014 John Wiley & Sons, Ltd.
Enzymatic hydration activity assessed by selective spectrophotometric detection of alcohols: A novel screening assay using oleate hydratase as a model enzyme
Authors: Hiseni Aida , Medici Rosario , Arends Isabel W. C. E. , Otten Linda G.
Published: January 2014

Hydroxy fatty acids (HFAs) are high‐added‐value compounds, which are incorporated in polymers, lubricants, emulsifiers and stabilizers and have potential medicinal use. In nature, HFAs are regio‐specifically synthesized by several enzymes, including P450 monooxygenases, lipoxygenases, hydratases, 12‐hydroxylases, and diol synthases. The growing demand for HFAs warrants the development of simple and efficient analytical methods that enable high‐throughput detection of the hydroxylated product in the presence of its unsaturated precursor. Herein a novel high‐throughput assay for the detection of alcohols is described using oleate hydratase (OHase, EC 4.2.1.53) from Elizabethkingia meningoseptica as the model enzyme. The developed assay is based on the selective spectrophotometric detection of alkyl nitrites formed upon the reaction between the hydroxyl group and nitrous acid. The assay proved to discriminate between unsaturated fatty acids as well as small cyclic and acyclic unsaturated alkenes and their corresponding alcohols. Lower detection limits were 1.5–3 mM with excellent Z'‐factors. Enzymatic reactions using OHase with oleic acid resulted in somewhat lower Z‐factors for various enzyme preparations. This small scale assay can enable fast discovery of new microorganisms or improved enzymes from mutant libraries and will be useful for biocatalytic strategies involving fatty acid (de)hydrating enzymes.
Preoperative serum hyaluronic acid level as a prognostic factor in patients undergoing hepatic resection for hepatocellular carcinoma
Authors: Mima K , Beppu T , Ishiko T , Chikamoto A , Nakagawa S , Hayashi H , Watanabe M , Sakamaki K , Baba H
Published: January 2014

Background

Hyaluronic acid (HA) probably plays a critical role in tumorigenesis. The clinical significance of serum HA concentration in patients with hepatocellular carcinoma (HCC) remains to be elucidated. This study analysed the relationship between preoperative serum HA levels and prognosis after hepatic resection in patients with HCC.

Methods

Consecutive patients who underwent hepatic resection for HCC between September 1999 and March 2012 were included in this retrospective study. Serum HA levels were measured within 4 weeks before surgery by an immunoturbidimetric automated latex assay. The cut-off level for preoperative serum HA was validated using a time-dependent receiver operating characteristic (ROC) curve analysis. The prognostic impact of preoperative serum HA levels was analysed using Cox proportional hazards models.

Results

A total of 506 patients of median age 66 years (405 men, 80·0 per cent) were analysed. The median length of follow-up was 32 months. High serum HA levels (100 ng/ml or above) were associated with shorter recurrence-free survival (P < 0·001) (hazard ratio (HR) 1·50, 95 per cent confidence interval 1·17 to 1·93; P = 0·002) and overall survival (P = 0·001) (HR 1·46, 1·03 to 2·07; P = 0·033). In patients with HCC without severe liver fibrosis, serum HA level was correlated with multiple tumours (P = 0·039), early recurrence (P = 0·033), and poor recurrence-free (P < 0·001) and overall (P = 0·024) survival.

Conclusion

High preoperative serum HA levels predict poor prognosis in patients with HCC after hepatic resection, and may serve as a future biomarker.
Getting started in the scholarship of teaching and learning: A “how to” guide for science academics
Authors: Rowland Susan L. , Myatt Paula M.
Published: January 2014

SoTL stands for the Scholarship of Teaching and Learning. The acronym, said “sottle” or “sote—all,” describes research that involves rigorous examination of teaching and learning by faculty who are actively involved in the educational process. The number of natural‐science faculty engaged in SoTL is increasing, and their important work has broad implications for the measurement and improvement of college teaching and learning outcomes. The data show, however, that many faculty who conduct SoTL projects in science departments begin their education research careers with no training in SoTL research methodologies, and find they are working alone, with few colleagues who can nurture (or even understand) their efforts. In this article we provide a guide intended to help natural‐science faculty initiate SoTL projects while they negotiate the mechanics and politics of developing and maintaining a SoTL research program in a science department. © 2013 by The International Union of Biochemistry and Molecular Biology, 42(1):6–14, 2014
Subcortical anatomy of the lateral association fascicles of the brain: A review
Authors: Martino Juan , De Lucas Enrique Marco
Published: January 2014

Precise knowledge of the connectivities of the different white matter bundles is of great value for neuroscience research. Our knowledge of subcortical anatomy has improved exponentially during recent decades owing to the development of magnetic resonance diffusion tensor imaging tractography (DTI). Although DTI tractography has led to important progress in understanding white matter anatomy, the precise trajectory and cortical connections of the subcortical bundles remain poorly determined. The recent literature was extensively reviewed in order to analyze the trajectories and cortical terminations of the lateral association fibers of the brain.The anatomy of the following tracts is reviewed: superior longitudinal fasciculus, middle longitudinal fasciculus, inferior longitudinal fasciculus, inferior fronto‐occipital fasciculus, uncinate fasciculus, frontal aslant tract, and vertical occipital fasciculus. The functional role of a tract can be inferred from its topography within the brain. Knowing the functional roles of the cortical areas connected by a certain bundle, it is possible to develop new insights into the putative functional properties of such connections. Clin. Anat. 563–569, 2014. © 2014 Wiley Periodicals, Inc.
Clinical and surgical anatomy of the liver: A review for clinicians
Authors: Juza Ryan M. , Pauli Eric M.
Published: January 2014

The liver is the largest gland in the body occupying 2.5% of total body weight and providing a host of functions necessary for maintaining normal physiological homeostasis. Despite the complexity of its functions, the liver has a homogenous appearance, making hepatic anatomy a challenging topic of discussion. To address this issue, scholars have devoted time to establishing a framework for describing hepatic anatomy to aid clinicians. Work by the anatomist Sir James Cantlie provided the first accurate division between the right and left liver in 1897. The French surgeon and anatomist Claude Couinaud provided additional insight by introducing the Couinaud segments on the basis of hepatic vasculature. These fundamental studies provided a framework for medical and surgical discussions of hepatic anatomy and were essential for the advancement of modern medicine. In this article, the authors review the normal anatomy and physiology of the liver with a view to enhancing the clinician's knowledge base. They also provide a convenient model to assist with understanding and discussion of liver anatomy. Clin. Anat. 27:764–769, 2014. © 2014 Wiley Periodicals, Inc.
Rare Bisindole Alkaloids from the Amazonian Tree Raputia simulans
Authors: Vougogiannopoulou Konstantina , Travasarou Aikaterini , Fokialakis Nikolas , Skaltsounis Alexios L.
Published: January 2014

The stem bark of Raputia simulans (Rutaceae) has been reported to contain simple and dimeric indole alkaloids. Further phytochemical investigation of R. simulans stem bark resulted in the isolation of three new alkaloids. These compounds represent a relatively new category of dimeric indole alkaloids with a cyclohexene moiety in their core. Their structure elucidations were based on NMR and HR‐MS techniques, while structural aspects concerning their relative configuration were investigated using molecular mechanics calculations and NOESY experiments.
Cytotoxic Polyphenols from a Sponge‐Associated Fungus Aspergillus versicolor Hmp‐48
Authors: Wang Xiao , Mou Yanhua , Hu Jiangchun , Wang Nan , Zhao Li , Liu Li , Wang Shujin , Meng Dali
Published: January 2014

A new dibenzo[1,4]dioxin 1, and two new prenylated diphenyl ethers, 2 and 3, together with six known compounds, 4–9, were isolated from a sponge‐associated fungus Aspergillus versicolor Hmp‐F48 by bioactivity‐guided fractionation. Their structures were elucidated by 1D‐ and 2D‐NMR, and MS analyses. The compounds showed potent cell growth inhibitory activities against HL‐60 cell line.
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

Four 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

The 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

Invited 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

The 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

An 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

In 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

Plexiglas® 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

The 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

Theory 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.
Blood and beyond: Properties of circulating and tissue‐resident human virus‐specific αβ CD8+ T cells
Authors: van Aalderen Michiel C. , Remmerswaal Ester B. M. , ten Berge Ineke J. M. , van Lier René A. W.
Published: January 2014

CD8+ αβ T‐cell responses form an essential line of defence against viral infections. An important part of the mechanisms that control the generation and maintenance of these responses have been elucidated in experimental mouse models. In recent years it has become clear that CD8+ T‐cell responses in humans not only show similarities, but also display differences to those occurring in mice. Furthermore, while several viral infections occur primarily in specialised organ systems, for obvious reasons, most human CD8+ T‐cell investigations were performed on cells deriving from the circulation. Indeed, several lines of evidence now point to essential functional differences between virus‐specific CD8+ memory T cells found in the circulation and those providing protection in organ systems, such as the lungs. In this review, we will focus on summarising recent insights into human CD8+ T‐cell differentiation in response to several viruses and emphasise that for a complete understanding of anti‐viral immunity, it is pivotal to scrutinise such responses in both blood and tissue.
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

Vehicle‐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

In 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

Many 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

High‐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.
Diving into the Goethe Period
Authors: Unterstell Rembert
Published: January 2014

Germanist and Emmy Noether group leader Simon Bunke studies cultural themes in the mirror of literary discourse. For him, the sheer diversity of his subject is the key.
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

Field 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.
Mitochondrial but not plasmalemmal BK channels are hypoxia‐sensitive in human glioma
Authors: Gu Xiang Q , Pamenter Matthew E. , Siemen Detlef , Sun Xiaolu , Haddad Gabriel G.
Published: January 2014

Tumor cells are resistant to hypoxia but the underlying mechanism(s) of this tolerance remain poorly understood. In healthy brain cells, plasmalemmal Ca2+‐activated K+ channels (plasmaBK) function as oxygen sensors and close under hypoxic conditions. Similarly, BK channels in the mitochondrial inner membrane (mitoBK) are also hypoxia sensitive and regulate reactive oxygen species production and also permeability transition pore formation. Both channel populations are therefore well situated to mediate cellular responses to hypoxia. In tumors, BK channel expression increases with malignancy, suggesting these channels contribute to tumor growth; therefore, we hypothesized that the sensitivity of plasmaBK and/or mitoBK to hypoxia differs between glioma and healthy brain cells. To test this, we examined the electrophysiological properties of plasmaBK and mitoBK from a human glioma cell line during normoxia and hypoxia. We observed single channel activities in whole cells and isolated mitoplasts with slope conductance of 199 ± 8 and 278 ± 10 pA, respectively. These currents were Ca2+‐ and voltage‐dependent, and were inhibited by the BK channel antagonist charybdotoxin (0.1 μM). plasmaBK could only be activated at membrane potentials >+40 mV and had a low open probability (NPo) that was unchanged by hypoxia. Conversely, mitoBK were active across a range of membrane potentials (−40 to +40 mV) and their NPo increased during hypoxia. Activating plasmaBK, but not mitoBK induced cell death and this effect was enhanced during hypoxia. We conclude that unlike in healthy brain cells, glioma mitoBK channels, but not plasmaBK channels are oxygen sensitive. GLIA 2014;62:504–513