bluuebunny/crossref_metadata_2025_split huggingface dataset:
Differences in polyadenylation site choice between somatic and male germ cells
Authors: McMahon K Wyatt , Hirsch Benjamin A , MacDonald Clinton C 
Published: October 2006

Abstract

Background
We have previously noted that there were differences in somatic and male germ cell polyadenylation site choices. First, male germ cells showed a lower incidence of the sequence AAUAAA (an important element for somatic polyadenylation site choice) near the polyadenylation site choice. Second, the polyadenylation sites chosen in male germ cells tended to be nearer the 5' end of the mRNA than those chosen in somatic cells. Finally, a number of mRNAs used a different polyadenylation site in male germ cells than in somatic cells. These differences suggested that male germ cell-specific polyadenylation sites may be poor substrates for polyadenylation in somatic cells. We therefore hypothesized that male germ cell-specific polyadenylation sites would be inefficiently used in somatic cells.

Results
We tested whether pre-mRNA sequences surrounding male germ cell-specific polyadenylation sites (polyadenylation cassettes) could be used to direct polyadenylation efficiently in somatic cells. To do this, we developed a luciferase reporter system in which luciferase activity correlated with polyadenylation efficiency. We showed that in somatic cells, somatic polyadenylation cassettes were efficiently polyadenylated, while male germ cell-specific polyadenylation cassettes were not. We also developed a sensitive, 3' RACE-based assay to analyze polyadenylation site choice. Using this assay, we demonstrated that male germ cell-specific polyadenylation cassettes were not polyadenylated at the expected site in somatic cells, but rather at aberrant sites upstream of the sites used in male germ cells. Finally, mutation of the male germ cell-specific poly(A) signal to a somatic poly(A) signal resulted in more efficient polyadenylation in somatic cells.

Conclusion
These data suggest that regulated polyadenylation site choice of male germ cell-specific polyadenylation sites requires one or more factors that are absent from somatic cells.
5' long terminal repeat (LTR)-selective methylation of latently infected HIV-1 provirus that is demethylated by reactivation signals
Authors: Ishida Takaomi , Hamano Akiko , Koiwa Tsukasa , Watanabe Toshiki 
Published: October 2006

Abstract
We previously described selective hypermethylation of the 5'-long terminal repeat (LTR) of HTLV-1 provirus in vivo and in vitro. This prompted us to analyze CpG methylation of the two LTRs of the HIV provirus in chronically infected cell lines. The results demonstrate selective hypermethylation of the 5' LTR of the HIV provirus in ACH-2 cells. Moreover, induction of viral gene expression by TNF-α resulted in demethylation of the 5'-LTR. These results suggest that selective epigenetic modification of the 5'LTR of the HIV-1 provirus may be an important mechanism by which proviral activity is suppressed.
Highly Efficient Suzuki Coupling Reaction of α‐Chloroalkylidene‐β‐lactones and β‐Lactams with Organoboronic Acids
Authors: Ma Shengming , Jiang Xuefeng , Cheng Xin , Hou Hairong 
Published: October 2006

AbstractThe activation of CCl bond of (Z)‐α‐chloroalkylidene‐β‐lactones and (E)‐α‐chloroalkylidene‐β‐lactams via the Suzuki cross‐coupling reaction is reported in this paper. Alkyl, heteroaromatic, substituted phenyl‐ and alkenylboronic acids can be coupled with a wide variety of α‐chloroalkylidene‐β‐lactones and β‐lactams in excellent yields within a short period of time. The cross‐coupling reaction of optically active substrates leads to the optically active compounds without racemization of the corresponding chiral center.
Lewis Acid‐Catalyzed Direct Amination of Benzhydryl Alcohols
Authors: Terrasson Vincent , Marque Sylvain , Georgy Marie , Campagne Jean‐Marc , Prim Damien 
Published: October 2006

AbstractThe Lewis acid‐mediated direct amination of benzylic alcohols is described, providing various benzylic amine derivatives in good yields under mild and environmentally benign conditions. Among the different Lewis acids tested, gold(III) proved to be the catalyst of choice for both chemical (yield, conversion) and practical reasons (a filtration over a silica pad is generally sufficient to obtain the corresponding benzylic amine in analytically pure form).
Organocatalytic, Enantioselective Conjugate Addition of Nitroalkanes to Nitroolefins
Authors: Wang Jian , Li Hao , Zu Liansuo , Jiang Wei , Wang Wei 
Published: October 2006

AbstractAn organocatalytic, enantioselective conjugate addition reaction of nitroalkanes with nitroolefins has been developed under neat conditions without using an organic solvent. The process, catalyzed by a modified Cinchona alkaloid, affords synthetically useful 1,3‐dinitro compounds in good yields (70–82 %) with good degrees of enantioselectivity (67–88 % ee).
4,4′‐Disubstituted L‐Prolines as Highly Enantioselective Catalysts for Direct Aldol Reactions
Authors: Gu Liuqun , Yu Menglong , Wu Xiaoyu , Zhang Yazhu , Zhao Gang 
Published: October 2006

AbstractA new series of 4,4′‐disubstituted prolines (1a–h) has been developed and tested as organocatalysts in the direct catalytic asymmetric aldol reaction of several aliphatic ketones with aldehydes. Catalyst 1g affords the best enantioselectivities for this transformation. The reaction was carried out in DMF using a catalyst loading of 10 mol % at −10 °C to give the aldol products in up to 97 % ee for acetone. In the cases of cyclohexanone and cyclopentanone, the corresponding anti‐products were obtained in 94 % ee.
Versatile Synthesis of Pyrrole‐2‐acetic Esters and (Pyridine‐2‐one)‐3‐acetic Amides by Palladium‐Catalyzed, Carbon Dioxide‐Promoted Oxidative Carbonylation of (Z)‐(2‐En‐4‐ynyl)amines
Authors: Gabriele Bartolo , Salerno Giuseppe , Fazio Alessia , Veltri Lucia 
Published: October 2006

AbstractThe oxidative carbonylation of readily available (Z)‐(2‐en‐4‐ynyl)amines, catalyzed by the PdI2‐KI system, selectively afforded in satisfactory yields (40–95 %) either pyrrole‐2‐acetic ester or (pyridine‐2‐one)‐3‐acetic amide derivatives, depending on the susbtitution pattern of the substrate and the reaction conditions. The presence of an excess of carbon dioxide proved in most cases to be beneficial to both the reaction rate and product selectivity.
Cyclopropyl Building Blocks for Organic Synthesis, 131. Palladium‐Catalyzed Bicyclization with Carbonyl Insertion of Alkenyl‐Tethered Propargyl Carbonates Towards a Scalable Synthesis of Various 2‐(Bicyclo[3.1.0]hex‐1‐yl)acrylates
Authors: Bagutski Viktor , Moszner Norbert , Zeuner Frank , Fischer Urs Karl , de Meijere Armin 
Published: October 2006

AbstractThe Pd‐catalyzed 5‐exo‐trig‐3‐exo‐trig cascade cyclization of 1,6‐enynes with a propargyl carbonate terminus offers the shortest synthetic route to variously substituted 2‐(bicyclo[3.1.0]hex‐1‐yl)acrylates, a novel class of prospective monomers for low‐shrinkage polymers. To apply this reaction to large‐scale preparations of the said bicyclic acrylates, a flexible Pd catalyst system with tunable reactivity has been developed. The dependence of the product and diastereomer distribution on both the reaction conditions, including the type of palladium catalyst used, and on the nature of the substrate has been investigated. A variety of methyl 2‐(bicyclo[3.1.0]hex‐1‐yl)acrylates and parent carboxylic acids as well as some of their derivatives of potential interest towards a technical application were prepared on a multigram scale. A general large‐scale synthesis of the cyclization precursors bearing one or two carbonyl groups in the tether is also disclosed.
A Catalytic Enantioselective Imino‐Reformatsky Reaction
Authors: Cozzi Pier Giorgio 
Published: October 2006

AbstractThe admission of air in the reaction mixture of imine, ethyl iodoacetate and dimethylzinc, in the presence of 20–30 mol % of inexpensive and commercially available N‐methylephedrine as the chiral ligand, promoted the Reformatsky reaction, without the need for other metals or catalysts. Excellent yields (up to 92 %) and enantioselectivities (83–94 %) were obtained for the tested substrates. The reaction shows a broad scope, and all the imines are prepared in situ, using Me2Zn as the dehydrating agent.
Waste‐Free Electrochemical Oxidation of Alcohols in Water
Authors: Palmisano Giovanni , Ciriminna Rosaria , Pagliaro Mario 
Published: October 2006

AbstractWe describe a new sol‐gel molecular electrode made of a thin layer of organosilica doped with the nitroxyl radical TEMPO (2,2,6,6‐tetramethylpiperidine‐1‐oxyl) electrodeposited on the surface of an ITO‐coated glass and its employment as a selective and versatile oxidation catalyst in the electrochemical conversion of different alcohols to carbonyl compounds. Environmentally friendly water or a water/acetonitrile mixture buffered with bicarbonate is used as solvent. The electrode is highly stable and it can be reused for a prolonged period of time allowing easy separation from the products.
Palladium‐Catalyzed Intermolecular Asymmetric Hydroamination with 4,4′‐Disubstituted BINAP and SEGPHOS
Authors: Hu Aiguo , Ogasawara Masamichi , Sakamoto Takeshi , Okada Atsushi , Nakajima Kiyohiko , Takahashi Tamotsu , Lin Wenbin 
Published: October 2006

AbstractA family of tunable precatalysts [Pd((S)‐L*)(NCMe)2](OTf)2, where L* is 4,4′‐disubstituted BINAP or SEGPHOS, was synthesized and used for the asymmetric intermolecular hydroamination of aniline to vinylarenes with ee values of up to 85 %, and it is believed that the bulky groups on the 4,4′‐positions and the narrower dihedral angle of the biaryl moiety are responsible for the ee enhancement in these reactions.
The First Catalytic Mannich‐Type Reaction of N‐Alkoxycarbonylamino Sulfones with Silyl Enolates
Authors: Ollevier Thierry , Nadeau Etienne , Eguillon Jean‐Christophe 
Published: October 2006

AbstractBismuth triflate was found to be an efficient catalyst in the Mannich‐type reaction of silyl enolates with N‐alkoxycarbonylamino sulfones. The reaction proceeded smoothly with a low catalyst loading of bismuth triflate (0.5–1.0 mol %) to afford the corresponding protected β‐aminocarbonyl compound in very good yields (up to 96 %).
Synthese des unsubstituierten 3,5‐Dioxo‐1,2,4‐oxadiazolidins 34. Mitt. über Hydroxylamin‐Derivate
Authors: Zinner G. , Stoffel R. 
Published: October 2006

AbstractDurch Addition von Hydroxylamin an Alkoxycarbonylisocyanate erhält man 1‐Hydroxy‐3‐alkoxycarbonylharnstoffe, die im alkalischen Milieu zum unsubstituierten 3,5‐Dioxo‐1,2,4‐oxadiazolidin cyclisieren. Dieses läßt sich in 2‐ und 4‐Stellung methylieren und mit Xanthydrol xanthylieren.
Synthesis of N‐(9H‐Xanthen‐9‐yl)aminoalkanamide and N‐(9H‐Thioxanthen‐9‐yl)aminoalkanamide Derivatives and their in vitro Evaluation as Potential Intercalators and Antitumor Drugs
Authors: Filippatos Evangelos , Papadaki‐Valiraki Aspasia , Todoulou Ourania , Jacquemin‐Sablon Alain 
Published: October 2006

AbstractA series of new N‐(9H‐xanthen‐9‐yl)aminoalkanamide and N‐(9H‐thio‐xanthen‐9‐yl)aminoalkanamide derivatives was synthesized and evaluated as potential intercalators by measuring their DNA binding affinity. They were also tested for cytotoxic activity against L1210. The results suggest that the cytotoxicity of these molecules was not due to an intercalating mechanism.
Substituierte 2‐Aminonicotinonitrile
Authors: Troschütz Reinhard , Dennstedt Thomas 
Published: October 2006

AbstractDie Aminolyse des Cyanketen‐O N‐Acetal‐Gemisches 1 Z/E mit den Aminen 2a,b führt zu den E‐konfigurierten primär/sekundären Cyanketenaminalen 3a,b. Durch Reaktion von 3a,b mit der, 1,3‐Biselektrophilen 4, 6a,b, 9 HCl, 12, 13, 15a,b, 17 und 19 lassen sich die N2‐substituierten 2‐Aminonicotinonitrile 5, 7, 8, 10, 11, 14, 16 und 20 herstellen. Umsetzung der 2‐Aminonicotinonitrile mit α‐Phenylethylrest in Position 2 (14b, 16a, 8a, 20b, 5 und 8b) mit Polyphosphorsäure führt zu den primären 2‐Aminonicotinonitrile 21a‐f.
Synthesis of Antitumour Carbon‐Bridged Imidazopyridazine Carbamates
Authors: Denyer Clive V. , Reddy Michael T. , Jenkins D. Con , Rapson Elaine , Watts Stuart D. M. 
Published: October 2006

AbstractTwo carbon‐bridged analogues 11 and 15 of the potent microtubule inhibitor BW1069C85 (1) have been synthesised and evaluated for antitubulin and antitumour activity in vitro. Though the compounds were somewhat less potent than BW1069C85, significant activity against tubulin polymerisation and cell proliferation was demonstrated in the assays.
Wirkung neuer Iminiumverbindungen gegen Bakterien und Pilze, 30. Mitt.: 3‐Alkoxymethyl‐1‐hexyl‐, 3‐Alkylthiomethyl‐1‐hexyl‐, 3‐Alkoxymethyl‐1‐oktyl‐ und 3‐Alkylthiomethyl‐1‐oktylbenzimidazoliumchloride
Authors: Pernak Juliusz , Skrzypczak Andrzej , Krysiński Jerzy , Kaźmierczak Maria , Jedraszczyk Janina , Michalak Lucyna 
Published: October 2006

AbstractEs werden Synthesen und antimikrobielle Wirkung der Titelverbindungen beschrieben. Die Verbindungen wurden durch Quaternisierung von 1‐Hexyl‐ bzw. 1‐Oktylbenzimidazol mit Chlormethylalkylsulfid bzw. Chlormethylalkylether gewonnen. Die antimikrobielle Wirkung wurde gegen‐über 13 Bakterien‐ und Pilzstämmen geprüft. Die höchste Aktivität zeigten die Verbindungen mit dem Oktylthiomethyl‐ und Decyloxymethylrest.
Novel Synthesis of 1,3,4‐Thiadiazine Derivatives and Their Cycloaddition Reactions
Authors: Wardakhan Wagnat W. 
Published: October 2006

Abstract4‐Phenyl‐3‐thiosemicarbazide 1 reacted with the α‐halocarbonyl compounds 2a, b to give the thiosemicarbazone derivatives 3a, b. The latter compounds underwent cyclization to the 1,3,4‐thiadiazine derivatives 4a, b which underwent [2 + 4] cycloaddition reactions to give the 4H‐thiopyran derivatives 7a, b. The chemistry of these thiopyrans was studied. Some of the fused derivatives among them compounds 20a, 20b, 21a, 21b allowed good mycelial growth and sporulation by the two fungi. This indicates that the two fungi can use the N‐containing heterocyclic ring as a nitrogen source.
The production of (R)‐2‐hydroxy‐1‐phenyl‐propan‐1‐one derivatives by benzaldehyde lyase from Pseudomonas fluorescens in a continuously operated membrane reactor
Authors: Hildebrand Falk , Kühl Sven , Pohl Martina , Vasic‐Racki Durda , Müller Michael , Wandrey Christian , Lütz Stephan 
Published: October 2006

AbstractBenzaldehyde lyase (BAL; E.C. 4.1.2.38) from Pseudomonas fluorescens Biovar I catalyzes the reversible formation of benzoins from aromatic aldehydes, and, moreover, the coupling of aromatic with aliphatic aldehydes yielding derivatives of (R)‐2‐hydroxy‐1‐phenyl‐ propan‐1‐one (R)‐HPPs), which are important chiral building blocks. In this paper, we report on the development of a reactor system that allows the selective production of substituted (R)‐HPP‐derivatives. The reaction systems yielding (R)‐1‐(3‐chloro‐phenyl)‐2‐hydroxy‐ propan‐1‐one, (R)‐2‐hydroxy‐3‐methoxy‐1‐(4‐methoxy‐phenyl)‐propan‐1‐one, and (R)‐2‐hydroxy‐3,3‐dimethoxy‐1‐phenyl‐propan‐1‐one were investigated. A kinetic model optimized by batch experiments was developed, for the description of both batch and continuously operated reactors. This model was used to describe the HPP production in a continuously operated enzyme membrane reactor. The reactor type used combines the advantages of high conversion and excellent selectivity with high space‐time yields and total turnover numbers of up to ttn = 43,000. Products were obtained in high yield on a gram scale. Biotechnol. Bioeng. 2007;96:835–843. © 2006 Wiley Periodicals, Inc.
Quality measures for the use of adjuvant chemotherapy and radiation therapy in patients with colorectal cancer
Authors: Prosnitz Robert G. , Patwardhan Meenal B. , Samsa Gregory P. , Mantyh Christopher R. , Fisher Deborah A. , McCrory Douglas C. , Cline Kathryn E. , Gray Rebecca N. , Morse Michael A. 
Published: October 2006

AbstractBACKGROUND.Chemotherapy (CT) and radiation therapy (RT) are essential components of adjuvant (preoperative or postoperative) therapy for many patients with colorectal cancer (CRC); however, quality measures (QMs) of these critical aspects of CRC treatment have not been characterized well. Therefore, the authors conducted a systematic review of the literature to determine the available QMs for adjuvant CT and RT in patients with CRC and rated their usefulness for assessing the delivery of quality care.METHODS.The MEDLINE and Cochrane data bases were searched for all publications that contained potential/actual QMs pertaining to adjuvant therapy for CRC. Identified QMs were rated by using criteria developed by the National Quality Forum.RESULTS.Thirty‐two articles met the established inclusion/exclusion criteria. Those 32 articles contained 12 potential or actual QMs, 6 of which had major flaws that limited their applicability. The most useful QMs identified were 1) the percentage of patients with AJCC Stage III colon cancer who received postoperative CT and 2) the percentage of patients with Stage II or III rectal cancer who received chemoradiotherapy.CONCLUSIONS.To the authors' knowledge, very few QMs pertaining to adjuvant CT or RT for CRC have been published to date, and only half of those measures were rated as useful, acceptable, and valid in the current literature review. Future research should focus on refining existing QMs and on developing new QMs that target important leverage points with respect to the provision of adjuvant therapy for patients with CRC. Cancer 2006. © 2006 American Cancer Society.
A Grid‐based algorithm for the solution of non‐Markovian stochastic Petri nets
Authors: Distefano S. , Puliafito A. , Scarpa M. 
Published: October 2006

AbstractWebSPN is a modeling tool for the analysis of non‐Markovian stochastic Petri nets that we developed some years ago. Its solution algorithm is based on a discretization of time and an approximation of non‐exponentially distributed firing time transitions by means of the phase‐type distributions. In order to solve the problems related to the management of the state space (which can become very large) we parallelized the solution algorithm through the MPICH libraries. To improve the MPICH parallel implementation with an adequate security management, a more efficient load distribution and fault‐tolerance capabilities, in this paper we propose the porting of WebSPN from the MPI to the Grid computational paradigm. In addition to a better flexibility in accessing computational and storage resources, one of the main advantages is the introduction of a fault recovery system to detect and recover from potential machine faults. The resulting new tool is named GridSPN. Copyright © 2006 John Wiley & Sons, Ltd.
A peer‐to‐peer decentralized strategy for resource management in computational Grids
Authors: Di Stefano Antonella , Santoro Corrado 
Published: October 2006

AbstractThis paper presents a peer‐to‐peer (P2P) approach for the management, in a computational Grid, of those resources that are featured by numerical quantity and thus characterized by a coefficient of utilization, such as percentage of CPU time, disk space, memory space, etc. The proposed approach exploits spatial computing concepts and models a Grid by means of a flat P2P architecture consisting of nodes connected by an overlay network; such a network topology, together with the quantity of resource available in each node, forms a three‐dimensional surface, where valleys correspond to nodes with a large quantity of available resource. In this scenario, this paper proposes an algorithm for resource discovery that is based on navigating such a surface, in search of the deepest valley (global minimum, that is, the best node). The algorithm, which aims at fairly distributing among nodes the quantity of leased resource, is based on some heuristics that mimic the laws of kinematics. Experimental results show the effectiveness of the algorithm. Copyright © 2006 John Wiley & Sons, Ltd.
4‐Thiolatobenzoato‐Bridged Rhodium/Zirconium Complexes: 32‐Membered Metallamacrocycles and Their Linear Dinuclear Counterparts
Authors: Helmstedt Ulrike , Lönnecke Peter , Reinhold Joachim , Hey‐Hawkins Evamarie 
Published: October 2006

AbstractThe heterometallic dinuclear complex [Cp*2Zr(Me){(μ‐OOCC6H4S)Rh(PEt3)3}] (3) is readily obtained by methane elimination in the reaction of [Rh(SC6H4COOH)(PEt3)3] with [Cp*2ZrMe2] in a 1:1 ratio. Complex 3 reacts with 1 equiv. of water to give [Cp*2Zr(OH){(μ‐OOCC6H4S)Rh(PEt3)3}] (4), a rare example of a terminal hydroxo complex of a zirconocene. Complexes 3 and 4 are isotypic. The influence of the zirconocene group on the properties of the rhodium complex was evaluated with 31P NMR spectroscopy, cyclic voltammetry and DFT calculations. [Cp*2ZrMe2] reacts with [{Rh(μ‐SC6H4COOH)(PPh3)2}2] (even in a 1:1 ratio at room temperature) or with [Rh(SC6H4COOH)(PEt3)3] (in a 1:2 ratio at elevated temperature) to give 32‐membered metallamacrocycles containing four rhodium and two zirconium atoms, in which each zirconocene group bridges two {Rh(SC6H4COO)(PR3)2}2 units [R = Ph (5), Et (6)]. The only significant structural difference in 5 and 6 is the presence of two different isomers, in which the bridging thiolato ligands occupy either the exo or the endo position of the Rh2S2 ring. However, this small difference has a significant influence on the size of the macrocyclic cavity. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)
Cu/Zn/Al Xerogels and Aerogels Prepared by a Sol–Gel Reaction as Catalysts for Methanol Synthesis
Authors: Guo Yanzhi , Meyer‐Zaika Wolfgang , Muhler Martin , Vukojević Sascha , Epple Matthias 
Published: October 2006

AbstractZnO/Al2O3, CuO/Al2O3, and CuO/ZnO/Al2O3 xerogels and aerogels have been prepared by a sol–gel route using propylene oxide as gelation initiator. For aerogel preparation, the solvent was extracted with supercritical CO2. Calcination of these xerogels and aerogels was followed by thermogravimetry (TG), and the microstructure of these calcined xerogels and aerogels was investigated by TEM, powder XRD, EXAFS, and nitrogen physisorption (BET, BJH). The oxide mixtures CuO/Al2O3 and CuO/ZnO/Al2O3 were also studied by temperature‐programmed reduction (TPR), and their catalytic activity in the formation of methanol from CO/CO2/H2 synthesis gas was measured. The aerogels have a higher specific surface area and a higher Cu surface area than the corresponding xerogels, which results in a higher catalytic activity for methanol synthesis. The presence of ZnO significantly increases the catalytic activities of both the xerogel and the aerogel. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)
Enantioselective Michael‐Type Friedel–Crafts Reactions of Indoles to Enones Catalyzed by a Chiral Camphor‐Based Brønsted Acid
Authors: Zhou Wei , Xu Li‐Wen , Li Lyi , Yang Lei , Xia Chun‐Gu 
Published: October 2006

AbstractChiral Brønsted acid, D‐camphorsulfonic acid, was found to be practical and efficient in the catalysis of the enantioselective Michael‐type Friedel–Crafts reactions of indoles with aromatic enones to afford the corresponding β‐indolyl ketones in excellent yields and moderate enantioselectivities. A surprising synergistic effect was discovered between BmimBr and D‐CSA which leads to active catalytic systems for the Friedel–Crafts reaction. The efficiency of these systems might result from the catalytic Lewis acid activation of the Brønsted acids. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)