bluuebunny/crossref_metadata_2025_split huggingface dataset:
Bronze Age paleohydrography of the southern Venetian Plain
Authors: Piovan Silvia , Mozzi Paolo , Stefani Cristina 
Published: December 2009

AbstractThe Bronze Age paleohydrography of the distal Adige and Po alluvial plain (northeastern Italy) is notable for its relations with protohistoric human activities in this area. This paper regards the stratigraphy and petrography of the Saline–Cona alluvial ridge, upon which the Saline, Sarzano, and Cantarana Bronze Age sites lie, and the petrography of Fratta alluvial ridge, upon which the Frattesina complex (Bronze–Iron Age) lies. Sand analyses indicate the Po River as the source for sediments underlying the alluvial ridge that runs through Fratta Polesine, Rovigo, Sarzano, and Cona. Radiometric ages indicate that the branch of the Saline–Cona ridge was formed by the Po River between the second half of the 3rd millennium B.C. and the end of 2nd millennium B.C. This ridge represents the maximum northward expansion of the Po alluvial system, through the same area of coastal plain crossed by the Adige and Brenta paleochannels. This paleohydrographic setting implies that fluvial connections between the Central Po Plain settlements, the Venetian Plain and Alps were relatively less complex in the Early and Middle Bronze Age than in the Late Bronze Age, when the terminal reach of the Po River was separated by the Adige River by hundreds of km2 of swampy terrain. © 2009 Wiley Periodicals, Inc.
Two New Homo‐aro‐cholestane Glycosides and a New Cholestane Glycoside from the Roots and Rhizomes of Paris polyphylla var. pseudothibetica
Authors: Xiao Cao‐Mao , Huang Jing , Zhong Xue‐Mei , Tan Xiao‐Yan , Deng Peng‐Chi 
Published: December 2009

AbstractTwo new homo‐aro‐cholestane glycosides and a new cholestane glycoside, along with three known saponins, were isolated from the 95% EtOH extract of the roots and rhizomes of Paris polyphylla var. pseudothibetica. The structures of the new compounds were elucidated as 3β‐O‐{α‐L‐rhamnopyranosyl‐(1→4)‐α‐L‐rhamnopyranosyl‐(1→4)‐[α‐L‐rhamnopyranosyl‐(1→2)]}‐β‐D‐glucopyranosylhomo‐aro‐cholest‐5‐ene‐26‐O‐β‐D‐glucopyranoside (parispseudoside A, 1), 3β‐O‐α‐L‐rhamnopyranosyl‐(1→2)‐β‐D‐glucopyranosylhomo‐aro‐cholest‐5‐ene‐26‐O‐β‐D‐glucopyranoside (parispseudoside B, 2), and (25R)‐3β‐O‐{α‐L‐rhamnopyranosyl‐(1→4)‐α‐L‐rhamnopyranosyl‐(1→4)‐[α‐L‐rhamnopyranosyl‐(1→2)]}‐β‐D‐glucopyranosyl‐cholesta‐5,17(20)‐diene‐16,22‐dione‐26‐O‐β‐D‐glucopyranoside (parispseudoside C, 3) by spectroscopic methods, including 1D‐ and 2D‐NMR, and MS experiments, as well as chemical evidences.
C21 Steroidal Glycosides from Cynanchum wilfordii
Authors: Xiang Wen‐Juan , Ma Lei , Hu Li‐Hong 
Published: December 2009

AbstractEight new C21 steroidal glycosides, named wilfosides A–H (1–8, resp.), along with one known compound wilfoside KIN (9), were isolated from the roots of Cynanchum wilfordii. The structures of the new glycosides were determined on the basis of spectroscopic analysis, including 1D‐ and 2D‐NMR, and ESI‐MS techniques, as well as by comparison of the spectral data with those of related compounds.
Two New Guaiane Sesquiterpenes from the Fruits of Daucus carota
Authors: Yi Tao , Zhang Lin , Fu Hong‐Wei , Yang Shi‐Lin , Tian Jing‐Kui 
Published: December 2009

AbstractTwo new sesquiterpenes, 11‐(acetyloxy)torilolone (1) and 1β‐hydroxytorilolone (2) were obtained from the fruits of Daucus carota. Their structures were elucidated on the basis of various spectroscopic analyses and chemical evidence.
Three New ent‐Trachylobane Diterpenoids from Co‐cultures of the Calli of Trewia nudiflora and Fusarium sp. WXE
Authors: Wu Xin , Lu Chun‐Hua , Shen Yue‐Mao 
Published: December 2009

AbstractFive diterpenoids, including three new ent‐trachylobane diterpenoids, i.e., (3α)‐3‐hydroxy‐ent‐trachylobane‐17,19‐dioic acid 19‐methyl ester (1), ent‐trachylobane‐17,19‐dioic acid 19‐methyl ester (2), ent‐trachylobane‐17,19‐dioic acid (3), and two known atisane‐type ones, i.e., (16α)‐16,17‐dihydroxy‐ent‐atisan‐19‐oic acid methyl ester (4), and 17‐hydroxy‐ent‐atisan‐19‐oic acid methyl ester (5), were isolated from the co‐culture extract of the calli of Trewia nudiflora and its endophytic fungus Fusarium sp. WXE. Their structures were elucidated by spectroscopic analyses, including 1D‐ and 2D‐NMR experiments, and HR‐Q‐TOF mass spectrometry. The antitumor and antibacterial properties of the new compounds were evaluated.
Nucleotides. Part LXXV
Authors: Maier Thomas , Pfleiderer Wolfgang 
Published: December 2009

AbstractThe reactivity of the 2′‐deoxy‐N4‐(phenoxycarbonyl)cytidine derivatives 3 and 4 with aromatic amines was studied to form new types of urea derivatives (see 5–10). On the same basis, labeling of 3 and 4 with 5‐aminofluorescein (14) was achieved to give the conjugates 15 and 17, respectively (Scheme 1). Treatment of 17 with 2‐(4‐nitrophenyl)ethanol in a Mitsunobu reaction led to double protection of the fluorescein moiety (→18) and desilylation yielded 19. Dimethoxytritylation (→20) and subsequent phosphitylations afforded the new building blocks 21 and 22. Synthesis of the fully protected trimer 28 was achieved by condensation of 21 with 23 to 26 which after detritylation (→27) was coupled with 25 to give 28 (Scheme 2). Deprotection of all blocking groups was performed with 1,8‐diazabicyclo[5.4.0]undec‐7‐ene (DBU) in one step to give 29. The synthesis of the decamer 5′‐d(CFluCCG GCC CGC)‐3′ (33) started from 30 which was attached to the solid support and then elongated with 31, 32, and 22 at the 5′‐terminal end (CFlu=deprotected phosphate derivative of 22). Hybridization with the complementary oligomer 5′‐d(G GGC CGG GCG)‐3′ (34) showed the influence of the fluorescein label on the stability of the duplex.
A New Iridoid Alkaloid from the Flowers of Plumeria rubra L. cv. acutifolia
Authors: Ye Guan , Li Zhi‐Xiong , Xia Guang‐Xin , Peng Hua , Sun Zhao‐Lin , Huang Cheng‐Gang 
Published: December 2009

AbstractA new iridoid alkaloid containing a spirolactone unit, plumericidine (1), was isolated from the flowers of Plumeria rubra L. cv. Acutifolia. Its structure was elucidated by spectroscopic evidence and confirmed by X‐ray diffraction crystallography. Its anticancer and antiviral activities were evaluated, but found to be insignificant.
Thermal [2+3]‐Cycloadditions of trans‐1‐Methyl‐2,3‐diphenylaziridine with CS and CC Dipolarophiles: An Unexpected Course with Dimethyl Dicyanofumarate
Authors: Mlostoń Grzegorz , Urbaniak Katarzyna , Domagała Małgorzata , Pfitzner Arno , Zabel Manfred , Heimgartner Heinz 
Published: December 2009

AbstractThe thermal reaction of trans‐1‐methyl‐2,3‐diphenylaziridine (trans‐1a) with aromatic and cycloaliphatic thioketones 2 in boiling toluene yielded the corresponding cis‐2,4‐diphenyl‐1,3‐thiazolidines cis‐4 via conrotatory ring opening of trans‐1a and a concerted [2+3]‐cycloaddition of the intermediate (E,E)‐configured azomethine ylide 3a (Scheme 1). The analogous reaction of cis‐1a with dimethyl acetylenedicarboxylate (5) gave dimethyl trans‐2,5‐dihydro‐1‐methyl‐2,5‐diphenylpyrrole‐3,4‐dicarboxylate (trans‐6) in accord with orbital‐symmetry‐controlled reactions (Scheme 2). On the other hand, the reactions of cis‐1a and trans‐1a with dimethyl dicyanofumarate (7a), as well as that of cis‐1a and dimethyl dicyanomaleate (7b), led to mixtures of the same two stereoisomeric dimethyl 3,4‐dicyano‐1‐methyl‐2,5‐diphenylpyrrolidine‐3,4‐dicarboxylates 8a and 8b (Scheme 3). This result has to be explained via a stepwise reaction mechanism, in which the intermediate zwitterions 11a and 11b equilibrate (Scheme 6). In contrast, cis‐1,2,3‐triphenylaziridine (cis‐1b) and 7a gave only one stereoisomeric pyrrolidine‐3,4‐dicarboxylate 10, with the configuration expected on the basis of orbital‐symmetry control, i.e., via concerted reaction steps (Scheme 10). The configuration of 8a and 10, as well as that of a derivative of 8b, were established by X‐ray crystallography.
NMR‐Solution Structures and Affinities for the Human Somatostatin G‐Protein‐Coupled Receptors hsst1–5 of CF3 Derivatives of Sandostatin® (Octreotide)
Authors: Seebach Dieter , Widmer Hans , Capone Stefania , Ernst Richard , Bremi Tobias , Kieltsch Iris , Togni Antonio , Monna Dominique , Langenegger Daniel , Hoyer Daniel 
Published: December 2009

AbstractThe previously reported (Helv. Chim. Acta 2008, 91, 2035) derivatives of octreotide (1) with a (CF3)‐Trp substitution, i.e., 3, and with open‐chain structures, i.e., 2, 4, and 5, have been tested for their affinities to hsst1–5 receptors and subjected to a detailed NMR analysis. Their affinities vary from 15 nM to 5 μM, as compared to 0.6 nM to 0.8 μM for octreotide itself (Table 1). This decreased bioactivity may have had to be expected for the open‐chain compounds 4 and 5; possible reasons for this decrease in the case of CF3 derivative of octreotide, 3, are discussed. NMR Analysis (Tables 2 and 3) provides evidence for increased dynamics of all new derivatives 2–5. The dynamics of the octreotide molecule 1 was analyzed by (natural‐abundance) longitudinal 13C‐T1‐relaxation time measurements (Table 4), from which the conclusion is drawn that the backbone of the macrocycle is rather rigid on the time scale of this method.
Synthesis and High‐Resolution NMR Structure of a β3‐Octapeptide with and without a Tether Introduced by Olefin Metathesis
Authors: Ebert Marc‐Olivier , Gardiner James , Ballet Steven , Abell Andrew D. , Seebach Dieter 
Published: December 2009

AbstractBridging between (i)‐ and (i+3)‐positions in a β3‐peptide with a tether of appropriate length is expected to prevent the corresponding 314‐helix from unfolding (Fig. 1). The β3‐peptide H‐β3hVal‐β3hLys‐β3hSer(All)‐β3hPhe‐β3hGlu‐β3hSer(All)‐β3hTyr‐β3hIle‐OH (1; with allylated βhSer residues in 3‐ and 6‐position), and three tethered β‐peptides 2–4 (related to 1 through ring‐closing metathesis) have been synthesized (solid‐phase coupling, Fmoc strategy, on chlorotrityl resin; Scheme). A comparative CD analysis of the tethered β‐peptide 4 and its non‐tethered analogue 1 suggests that helical propensity is significantly enhanced (threefold CD intensity) by a (CH2)4 linker between the β3hSer side chains (Fig. 2). This conclusion is based on the premise that the intensity of the negative Cotton effect near 215 nm in the CD spectra of β3‐peptides represents a measure of ‘helical content’. An NMR analysis in CD3OH of the two β3‐octapeptide derivatives without (i.e., 1) and with tether (i.e., 4; Tables 1–6, and Figs. 4 and 5) provided structures of a degree of precision (by including the complete set of side chain–side chain and side chain–backbone NOEs) which is unrivaled in β‐peptide NMR‐solution‐structure determination. Comparison of the two structures (Fig. 5) reveals small differences in side‐chain arrangements (separate bundles of the ten lowest‐energy structures of 1 and 4, Fig. 5, A and B) with little deviation between the two backbones (superposition of all structures of 1 and 4, Fig. 5, C). Thus, the incorporation of a CH2O(CH2)4OCH2 linker between the backbone of the β3‐amino acids in 3‐ and 6‐position (as in 4) does accurately constrain the peptide into a 314‐helix. The NMR analysis, however, does not suggest an increase in the population of a 314‐helical backbone conformation by this linkage. Possible reasons for the discrepancy between the conclusion from the CD spectra and from the NMR analysis are discussed.
Effects of storm flow samplings on the evaluation of inorganic nitrogen and sulfate budgets in a small forested watershed
Authors: Chiwa Masaaki , Ide Jun'ichiro , Maruno Ryoko , Higashi Naoko , Otsuki Kyoichi 
Published: December 2009

AbstractTo investigate the effects of storm flow samplings on the evaluation of DIN and SO42− budgets, we conducted storm flow samplings and discrete interval (weekly) samplings of stream water, throughfall, and stemflow. This investigation lasted for three years and took place in a small forested watershed in western Japan. Annual exports were calculated by the sum of the load (ΣLtotal)‐ sum of the discharge (ΣQtotal) relationships obtained by storm flow samplings. These were then compared to calculated ones that were based on LQ relationships obtained by discrete interval sampling. The results of discrete interval sampling showed that the relationships of DIN or SO42− concentration to the discharge amount found in stream water differed from those of storm flow sampling. This was especially notable in years with higher annual precipitation and subsequent higher annual discharges. Also, exports of DIN and SO42− during storm flow periods accounted for 83% and 78% of annual exports on 3‐year averages, respectively. These results confirmed that storm flow samplings are essential for estimating annual exports of DIN and SO42−. Annual exports that were calculated based on just discrete interval sampling (46% and 17%, respectively) overestimated DIN and SO42− from discrete interval and storm flow samplings on a 3‐year average. These overestimates were pronounced in years of higher discharge, and critically affected the rates of net‐retention or export of DIN and SO42−. The relationship of smaller input than output of DIN was reversed if storm flow sampling was included. Copyright © 2009 John Wiley & Sons, Ltd.
Effects of sample and grid size on the accuracy and stability of regression‐based snow interpolation methods
Authors: Moreno J. Ignacio López , Latron J. , Lehmann A. 
Published: December 2009

AbstractThis work analyses the responses of four regression‐based interpolation methods for predicting snowpack distribution to changes in the number of data points (sample size) and resolution of the employed digital elevation model (DEM). For this purpose, we used data obtained from intensive and random sampling of snow depth (991 measurements) in a small catchment (6 km2) in the Pyrenees, Spain. Linear regression, classification trees, generalized additive models (GAMs), and a recent method based on a correction made by applying tree classification to GAM residuals were used to calculate snow‐depth distribution based on terrain characteristics under different combinations of sample size and DEM spatial resolution (grid size).The application of a tree classification to GAM residuals yielded the highest accuracy scores and the most stable models. The other tested methods yielded scores with slightly lower accuracy and varying levels of robustness under different conditions of grid and sample size. The accuracy of the model predictions declined with decreasing resolution of DEMs and sample size; however, the sensitivities of the models to the number of data points showed threshold values, which has implications (when planning fieldwork) for optimizing the relation between the effort expended in gathering data and the quality of the results. Copyright © 2009 John Wiley & Sons, Ltd.
Gastrin suppresses the interdependent expression of p16 and anion exchanger 1 favoring growth inhibition of gastric cancer cells
Authors: Tian Hua , Zhang Ning , Suo Wen‐Hao , Wang Ting , Song Ling‐Jun , Wu Jun , Liu Qiang , Shen Wei‐Wei , Fu Guo‐Hui 
Published: December 2009

AbstractOur previous studies demonstrated that expression and interaction of p16 with anion exchanger 1 (AE1) in gastric cancer cells is correlated with progression and shorter survival of the cancer. In this article, the effects of gastrin on p16 and AE1 and its implication in prevention and treatment of gastric cancer were studied by molecular biology techniques, animal experiment and clinical analysis. The results showed that expression of p16 in human gastric body carcinoma was downregulated along with the progression of the cancer, suggesting the reverse correlations between gastrin and p16 in vivo. Further experiments indicated that gastrin suppressed the expression of p16 via the p16 promoter and thereafter resulted in the degradation of AE1 in gastric cancer cells. Silencing of AE1 or p16 significantly inhibited the proliferation of the cancer cells. Using a xenograft tumor model in nude mice, we showed that experimental systemic hypergastrinemia induced by the administration of omeprazole led to decreased expression of AE1 and p16 as well as to a marked growth inhibition of SGC7901 tumors. It is concluded that a moderate plasma gastrin level is beneficial to the growth inhibition of gastric cancer by suppressing the expression of AE1 and p16. This finding may have an important implication for the prevention and treatment of cancers arise in the gastric antrum.
Accurate conformation‐dependent molecular electrostatic potentials for high‐throughput in silico drug discovery
Authors: Puranen J. Santeri , Vainio Mikko J. , Johnson Mark S. 
Published: December 2009

AbstractThe atom‐centered partial charges‐approximation is commonly used in current molecular modeling tools as a computationally inexpensive alternative to quantum mechanics for modeling electrostatics. Even today, the use of partial charges remains useful despite significant advances in improving the efficiency of ab initio methods. Here, we report on new parameters for the EEM and SFKEEM electronegativity equalization‐based methods for rapidly determining partial charges that will accurately model the electrostatic potential of flexible molecules. The developed parameters cover most pharmaceutically relevant chemistries, and charges obtained using these parameters reproduce the B3LYP/cc‐pVTZ reference electrostatic potential of a set of FDA‐approved drug molecules at best to an average accuracy of 13 ± 4 kJ mol−1; thus, equipped with these parameters electronegativity equalization‐based methods rival the current best non‐quantum mechanical methods, such as AM1‐BCC, in accuracy, yet incur a lower computational cost. Software implementations of EEM and SFKEEM, including the developed parameters, are included in the conformer‐generation tool BALLOON, available free of charge at http://web.abo.fi/fak/mnf/bkf/research/johnson/software.php. © 2009 Wiley Periodicals, Inc. J Comput Chem, 2010
Describing electron correlation effects in the framework of the elongation method—Elongation‐MP2: Formalism, implementation and efficiency
Authors: Makowski Marcin , Korchowiec Jacek , Gu Feng Long , Aoki Yuriko 
Published: December 2009

AbstractThe extension of the elongation method into description of electron correlation effects at ab intio level is presented. The formalism and implementation of the elongation‐MP2 methodology is discussed. The results of calculations for model systems are presented to illustrate efficiency and accuracy of the method. Directions of the further development are highlighted. © 2009 Wiley Periodicals, Inc. J Comput Chem, 2010
Parents and peers as providers of support in adolescents' social network: a developmental perspective
Authors: del Valle Jorge F. , Bravo Amaia , López Mónica 
Published: December 2009

AbstractThe authors carried out an assessment of social support networks with a sample of 884 Spanish adolescents aged 12 to 17. The main goal was to analyze the development of the figures of parents and peers as providers of social support in the two basic dimensions of emotional and instrumental support. In peers, they distinguished between the contexts from which they came (school, associations, and friends from the community) to observe whether there were different tendencies. The results of the MANOVA indicate significant effects on both dimensions for the factors age, provider, and interaction between the two. The authors conclude that the tendencies for decline in the provision of support from parents and the corresponding increase in support from peers during adolescence are different for each dimension, and also for the different types of friends, according to context. Parents maintain a good level of instrumental support, but not of emotional support. © 2009 Wiley Periodicals, Inc.
Tobacco sales in community pharmacies: remote decisions and demographic targets
Authors: Morton Cory M. , Peterson N. Andrew , Schneider John E. , Smith Brian J. , Armstead Theresa L. 
Published: December 2009

AbstractThis study applied multilevel modeling procedures with data from 678 community pharmacies and 382 residential census tracts in a Midwestern U.S. state to determine if two sets of variables: retail type (e.g., remotely owned, independently owned) and population demographics of the tracts in which outlets were located were associated with retail tobacco availability in community pharmacies. Data were derived from three archival sources: listings of all retailers in Iowa who obtained tobacco licenses in year 2003; all pharmacies registered with the Iowa Board of Pharmacy in 2003; and year 2000 census data. Refuting previous research, multilevel logistic regression results of this study demonstrate that population demographics, as well as retail type, significantly predict whether a community pharmacy sold tobacco. Pharmacies selling tobacco were more likely to be remotely owned outlets and located in areas with higher percentages of African American residents and higher median income. Implications for environmentally focused prevention interventions are discussed. © 2009 Wiley Periodicals, Inc.
Toll‐like receptor 2‐mediated peptidoglycan uptake by immature intestinal epithelial cells from apical side and exosome‐associated transcellular transcytosis
Authors: Bu Heng‐Fu , Wang Xiao , Tang Yi , Koti Viola , Tan Xiao‐Di 
Published: December 2009

AbstractPeptidoglycan (PGN) is a potent immune adjuvant derived from bacterial cell walls. Previous investigations suggest that intestinal epithelium may absorb PGN from the lumen. Nonetheless, how PGN is taken up and crosses intestinal epithelium remains largely unclear. Here, we first characterized PGN transport in vitro using IEC‐18 and HT29‐CL19A cells, which represent less mature epithelial cells in intestinal crypts. With fluorescent microscopy, we visualized internalization of dual‐labeled PGN by enterocytes. Engulfed PGN was found to form a complex with PGN recognition protein‐3, which may facilitate delivering PGN in vivo. Utilizing electronic microscopy, we revealed that uptake of apical PGN across intestinal epithelial monolayers was involved in phagocytosis, multivesicular body formation, and exosome secretion. We also studied transport of PGN using the transwell system. Our data indicated that apically loaded PGN was exocytosed to the basolateral compartment with exosomes by HT29‐CL19A cells. The PGN‐contained basolateral exosome extracts induced macrophage activation. Through gavaging mice with labeled PGN, we found that luminal PGN was taken up by columnar epithelial cells in crypts of the small intestine. Furthermore, we showed that pre‐confluent immature but not post‐confluent mature C2BBe1 cells engulfed PGN via a toll‐like receptor 2‐dependent manner. Together, our findings suggest that (1) crypt‐based immature intestinal epithelial cells play an important role in transport of luminal PGN over the intestinal epithelium; and (2) luminal PGN is transcytosed across intestinal epithelia via a toll‐like receptor 2‐mediated phagocytosis‐multivesicular body‐exosome pathway. The absorbed PGN and its derivatives may facilitate maintenance of intestinal immune homeostasis. J. Cell. Physiol. 222: 658–668, 2010. © 2009 Wiley‐Liss, Inc.