bluuebunny/crossref_metadata_2025_split huggingface dataset:
The time of timing: How Polycomb proteins regulate neurogenesis
Authors: Testa Giuseppe 
Published: June 2011

AbstractThe study of mammalian corticogenesis has revealed a critical role for Polycomb group (PcG) factors in timing the execution of developmental choices. Meanwhile, the study of post‐translational modifications of PcG factors marks a symmetrical point, namely that the activity of PcG proteins is itself timed in a manner that links progression through the cell cycle to targeting of downstream genes. Finally, in a third symmetrical twist, the studies that dissect the timing of neural fate by Polycomb are also uncovering the importance of timing in the experimental mutation, since ablation of the same PcG member at different developmental stages yields dramatically different results. Here, I weave together these three lines of evidence and develop a unifying model that clarifies the dynamics of Polycomb function in neural development and defines the salient challenges ahead.
Outcomes following a limited approach to radiotherapy in rectal cancer
Authors: Simunovic M , Jacob S , Coates A J , Vogt K , Moran B J , Heald R J 
Published: June 2011

Abstract

Background
Variation in the use of neoadjuvant and adjuvant radiotherapy for rectal cancer suggests an opportunity to avoid it in all but patients at highest risk of local recurrence.

Methods
Between 1 July 1999 and 1 February 2006, patients with primary rectal cancer were treated by a single surgeon operating at McMaster University, Hamilton, Ontario, Canada. Digital rectal examination and pelvic computed tomography were used to determine whether the mesorectal margin was threatened by tumour and thus whether preoperative radiotherapy would be needed. The study outcome was local tumour recurrence.

Results
Forty-six (48 per cent) of 96 patients received preoperative radiation therapy. The median follow-up was 4·2 years. Tumours were fixed or tethered in 31 (67 per cent) of the 46 irradiated patients. In contrast, no tumour was fixed in unirradiated patients and only ten (20 per cent) of the 50 tumours were tethered. The proportion of patients with stage I or II tumours based on final pathology was similar: 61 per cent (28 of 46) and 56 per cent (28 of 50) in irradiated and unirradiated groups respectively (P = 0·287). There were four (9 per cent) and two (4 per cent) local recurrences among irradiated and unirradiated patients respectively (P = 0·422).

Conclusion
Limiting preoperative radiotherapy in rectal cancer to patients with a threatened circumferential margin does not compromise patient outcome.
Operative notes do not reflect reality in laparoscopic cholecystectomy
Authors: Wauben L S G L , van Grevenstein W M U , Goossens R H M , van der Meulen F H , Lange J F 
Published: June 2011

Abstract

Background
Operative notes represent an essential element in safe patient care and should therefore be clear and accurate. This comparative study examined whether operative notes accurately represented the laparoscopic cholecystectomy (LC) as performed.

Methods
Nine Dutch teaching and non-teaching hospitals were invited to record 20 successive LCs each and to collect the corresponding operative notes. The main outcome measures were overall differences and correspondence between video recordings and notes based on the Dutch guideline for LC and the occurrence of iatrogenic gallbladder perforation. A comparison was made of the cumulative results of recordings and operative notes, and individual recordings were compared with the corresponding notes.

Results
Seven hospitals participated in the study; 125 video recordings and operative notes were fully analysed. Recordings showed more steps of the procedure than did notes. Individual comparisons showed significant differences (P≤0·001) between the recording and the corresponding note for the steps ‘Introducing trocars under vision’, ‘Condition of the gallbladder’, ‘Critical view of safety’ and ‘Removing first and second trocar under vision’. Iatrogenic gallbladder perforation with spilled bile occurred in 31 patients (24·8 per cent), and was both recorded and reported in 29 patients. Iatrogenic gallbladder perforation with spilled bile and spilled stones occurred in 15 patients (12·0 per cent), and was recorded and reported in 11 patients.

Conclusion
Operative notes do not adequately represent the actual LCs performed as they describe fewer important procedural steps. It is suggested that operative notes should include video recordings.
Migrants' Integration in Western Europe: Bridging Social Psychology and Political Science
Authors: Scuzzarello Sarah 
Published: June 2011

ABSTRACTThis article presents the possibilities and advantages of integrating social psychology and political science in the study of intergroup relations in diverse societies in Western Europe. Social psychology provides interesting insights in understanding the emotional and cognitive consequences of increased diversity. However, this literature tends to overlook the role of institutional discourses and correlated practices in stimulating or constraining positive intergroup relations. In order to fill these lacunae, the article suggests the integration of social psychology and a ‘political opportunity structure’ approach. This article maintains that the political opportunity structures operating in a context are not only important for understanding actors' mobilisation, as usually maintained in the literature, but also for studying the extent to which change at the micro‐level of social interaction can be stimulated or constrained. We illustrate the arguments of the article with an analysis of the narrative constructions and the correlated practices of integration as adopted by the city councils of Malmö and Bologna. Copyright © 2011 John Wiley & Sons, Ltd.
Characterization of a Sugar‐O‐methyltransferase TiaS5 Affords New Tiacumicin Analogues with Improved Antibacterial Properties and Reveals Substrate Promiscuity
Authors: Niu Siwen , Hu Tao , Li Sumei , Xiao Yi , Ma Liang , Zhang Guangtao , Zhang Haibo , Yang Xiaohong , Ju Jianhua , Zhang Changsheng 
Published: June 2011

AbstractThe 18‐membered macrocyclic glycoside tiacumicin B, an RNA polymerase inhibitor, is of great therapeutic significance in treating Clostridium difficile infections. The recent characterization of the tiacumicin B biosynthetic gene cluster from Dactylosporangium aurantiacum subsp. hamdenensis NRRL 18085 revealed the functions of two glycosyltransferases, a C‐methyltransferase, an acyltransferase, two cytochrome P450s, and a tailoring dihalogenase in tiacumicin biosynthesis. Here we report the genetic confirmation and biochemical characterization of TiaS5 as a sugar‐O‐methyltransferase, requisite for tiacumicin B biosynthesis. The tiaS5‐inactivation mutant is capable of producing 14 tiacumicin analogues (11 of which are new), all lacking the 2′‐O‐methyl group on the internal rhamnose moiety. Notably, two tiacumicin analogues exhibit improved antibacterial properties. We have also biochemically verified TiaS5 as an S‐adenosyl‐L‐methionine‐dependent O‐methyltransferase, requiring divalent metal ions for activity. Substrate probing revealed TiaS5 to be a promiscuous enzyme, recognizing 12 tiacumicin analogues. These findings unequivocally establish that TiaS5 functions as a 2′‐O‐methyltransferase and provide direct biochemical evidence that TiaS5‐catalyzed methylation is a tailoring step after glycosyl coupling in tiacumicin B biosynthesis.
STEM HAADF Image Simulation of the Orthorhombic M1 Phase in the Mo‐V‐Nb‐Te‐O Propane Oxidation Catalyst
Authors: Blom Douglas A. , Li Xin , Mitra Sonali , Vogt Thomas , Buttrey Douglas J. 
Published: June 2011

AbstractA full frozen phonon multislice simulation of high angle annular dark field scanning transmission electron microscopy (HAADF STEM) images from the M1 phase of the Mo‐V‐Nb‐Te‐O propane oxidation catalyst has been performed by using the latest structural model obtained using the Rietveld method. Simulated contrast results are compared with experimental HAADF images. Good agreement is observed at ring sites, however significant thickness dependence is noticed at the linking sites. The remaining discrepancies between the model based on Rietveld refinement and image simulations indicate that the sampling of a small volume element in HAADF STEM and averaging elemental contributions of a disordered site in a crystal slab by using the virtual crystal approximation might be problematic, especially if there is preferential Mo/V ordering near the (001) surface.
Molecular‐Glue‐Triggered DNA Assembly To Form a Robust and Photoresponsive Nano‐Network
Authors: Wang Chunyan , Pu Fang , Lin Youhui , Ren Jinsong , Dohn Chikara , Nakatani Kazuhiko , Qu Xiaogang 
Published: June 2011

AbstractA robust and photoresponsive DNA network has been designed and constructed from branched DNA and molecular glue. The molecular glue is photoswitchable and can specifically bind to G–G mismatched double‐stranded DNA. The assembly process can be reversibly controlled by manipulating the wavelength of light. The approach is flexible, allowing tuning of the size, morphology as well as the cavity of the network by variation of the molar ratio and the isotropic/anisotropic character of the branched building blocks. The assembled architectures are versatile and heat tolerant. These properties should allow the use of the network in further applications.
Local Measurement Techniques for Multiphase Flows
Authors: Schlüter Michael 
Published: June 2011

AbstractMehrphasenströmungen, in denen Tropfen, Blasen oder Feststoffpartikel in einer kontinuierlichen Phase vorliegen, beherrschen die überwiegende Zahl heutiger Prozesse der verfahrenstechnischen Industrie. Trotz der großen Bedeutung von Mehrphasenströmungen können Dispersphasen‐, Temperatur‐ und Konzentrationsverteilungen bisher nicht mit der geforderten Genauigkeit berechnet werden, da durch Grenzschichten und anisotrope Turbulenz sehr komplexe, strömungsmechanische Transportphänomene vorliegen, die auf sehr unterschiedlichen Größenskalen ablaufen. Für ein tieferes Verständnis der skalenübergreifenden Transportphänomene sind folglich lokale Messverfahren für Mehrphasenströmungen erforderlich, die Daten mit hoher räumlicher und zeitlicher Auflösung erfassen und die Strömung möglichst nicht beeinflussen. Es wird ein Überblick über einige derzeit verfügbare lokale Messverfahren gegeben, wobei nicht explizit zwischen Gas‐ und Flüssigströmungen unterschieden wird.
Identification of Xanthones as Selective Killers of Cancer Cells Overexpressing the ABC Transporter MRP1
Authors: Genoux‐Bastide Estelle , Lorendeau Doriane , Nicolle Edwige , Yahiaoui Samir , Magnard Sandrine , Di Pietro Attilio , Baubichon‐Cortay Hélène , Boumendjel Ahcène 
Published: June 2011

AbstractMultidrug‐resistance protein 1 (MRP1) belongs to the ATP‐binding cassette (ABC) transporter family. MRP1 mediates MDR (multidrug resistance) by causing drug efflux either by conjugation to glutathione (GSH) or by co‐transport with free GSH (without covalent bonding between the drug and GSH). We recently reported that the calcium channel blocker verapamil can activate massive GSH efflux in MRP1‐overexpressing cells, leading to cell death through apoptosis. However, clinical use of verapamil is hampered by its cardiotoxicity. Then, in the search for compounds that act similarly to verapamil, but without major side effects, we investigated xanthones. Herein we show that xanthones induce apoptosis among resistant cells overexpressing MRP1 similarly to the verapamil effect. Among the xanthones studied, 1,3‐dihydroxy‐6‐methoxyxanthone was identified as the most active derivative, able to specifically kill cells transfected with human MRP1 with even greater potency than verapamil. Under the same conditions, the active xanthones have no toxic effect on control (sensitive) cells. Xanthones could therefore be considered as new potential anticancer agents for the selective treatment of MRP1‐positive tumors.
Brønsted Acidity and the Medium: Fundamentals with a Focus on Ionic Liquids
Authors: Mihichuk Lynn M. , Driver Gordon W. , Johnson Keith E. 
Published: June 2011

AbstractFundamental aspects of Brønsted acidity in ionic liquid systems, in relation to those of simple protic molecules in the gas phase, pure protic molecules in the condensed phase and solutions of protic molecules in molecular systems, are presented. The variety of acidities possible, beyond those observed in aqueous systems, is emphasised and discussed in terms of differences of solvent levelling, ionisation, dissociation, homo‐/hetero‐conjugate ion speciation and the stabilisation of proton‐transfer products from solvent to solvent. It is argued that data regarding aqueous systems do not necessarily explain acid/base behaviour in other liquids satisfactorily. Methods of measuring acidity are reviewed, particularly by spectrophotometry and electrochemistry and recommendations proffered for estimating speciation and acidity of ionic liquids of various complexities.
Rate adaptation with loss diagnosis on IEEE 802.11 networks
Authors: Wu Shaoen , Biaz Saâd , Wang Honggang 
Published: June 2011

SUMMARYRate adaptation in wireless networking aims to seek the optimal data transmission rate most appropriate for current wireless channel conditions to make full use of the channel potentials. It is important in wireless networks because (1) most of them support multiple data rates, and (2) wireless channel is unstable with fast changes on which a single rate thereby may not be proper for long. Based on a comprehensive survey of the rate adaptation for IEEE 802.1 networks in literature, this work proposes a rate adaptation scheme, dubbedeffective rate adaptation(ERA), for IEEE 802.11 networks. ERA takes advantage of the fragmentation technique in IEEE 802.11 standard and utilizes the lowest rate retransmission in diagnosing frame loss cause (collision or channel degradation), diffusing collision, and promptly recovering frame losses. It also adopts an adaptive rate increase threshold concept to exploit channel potentials. Different from other rate adaptation schemes, ERA effectively addresses two challenges in rate adaptation on IEEE 802.11 networks: (1) it does not require RTS/CTS for loss diagnosis purpose; the use of RTS/CTS that are optional in IEEE standard results in inefficiency on channel utilization; (2) itpromptlyresponds to frame failure due to channel degradation, unlike others waiting till the end of a transmission window or cycle. With extensive simulation, ERA shows its unique strength in different lossy environments, especially in collision‐prone environments. Copyright © 2011 John Wiley & Sons, Ltd.
Effective allied network security system based on designed scheme with conditional legitimate probability against distributed network attacks and intrusions
Authors: Chen Ruey‐Maw , Hsieh Kuo‐Ta 
Published: June 2011

SUMMARYDependence on the Internet is increasing dramatically. Therefore, many researchers have given great attention to the issue of how to tighten Internet security. This study proposes a new scheme for the distributed intrusion prevention system (DIPS), in which the concept of ‘union’ is presented for satisfying the increasing requirements of Internet security issues. In this proposed design, the network intrusion detection system (NIDS) applies a misuse detection technique to detect well‐known intrusion behavior on the Internet. Meanwhile, for anomaly detection technique, a tool named ‘Scent’ (a network traffic sniffer) is combined with conditional legitimate probability to reveal previously undiscovered intrusion packets that do not match the intrusion signatures in NIDS. Moreover, blocking distributed denial‐of‐service (DDoS) attacks inside the protected allied network is also covered. To increase the detection accuracy, reduction of false positives and false negatives is also accomplished. Experimental results reveal that the suggested network security system scheme is effective and efficient in resolving the intrusion activity problem of real network environments. Copyright © 2011 John Wiley & Sons, Ltd.
Antigen‐presentation capacity of dendritic cells is impaired in ongoing enterovirus myocarditis
Authors: Rahnefeld Anna , Ebstein Frédéric , Albrecht Nadine , Opitz Elisa , Kuckelkorn Ulrike , Stangl Karl , Rehm Armin , Kloetzel Peter M. , Voigt Antje 
Published: June 2011

AbstractCoxsackievirus B3 (CVB3)‐infection is a frequent cause of acute myocarditis, which may result in chronic myocarditis and virus persistence. Investigation of the initial immune responses to CVB3 may shed light on the mechanisms that contribute to ongoing disease. DCs, as key professional APCs, were investigated in two MHC‐matched hosts: while C57BL/6 mice are resistant to chronic CVB3‐myocarditis, the A.BY/SnJ mouse strain exhibits susceptibility. DC maturation and activation were critically impaired in A.BY/SnJ mice, as reflected by the failure of DCs to induce co‐stimulatory molecules and cytokine/chemokine responses. MHC class I‐restricted antigen presentation via the cross‐presentation pathway was also affected in DCs from A.BY/SnJ mice. DC maturation involves the accumulation of DC aggresome‐like induced structures (DALISs) and the transient storage of defective ribosomal products (DRiPs). DCs from A.BY/SnJ mice showed permanent DALIS accumulation; the detection of poly‐ubiquitinylated CVB3 proteins in these DALISs suggested a limitation in the MHC class I antigenic supply in this host. In conclusion, ongoing chronic disease in A.BY/SnJ mice due to a failure to clear the virus may be attributed to defects in DC maturation/activation and DC MHC class I antigen processing.
Adaptive immune defects against glycoantigens in chronic granulomatous disease via dysregulated nitric oxide production
Authors: Lewis Colleen J. , Cobb Brian A. 
Published: June 2011

AbstractChronic granulomatous disease (CGD) is a primary immunodeficiency defined by mutations in the NADPH oxidase complex leading to reduced superoxide production, increased susceptibility to infection, chronic inflammation, and recurring abscess and granuloma formation. Here, we found that CGD mice were hyperresponsive to abscess‐inducing T‐cell‐dependent carbohydrate antigens (glycoantigens) due to a ten‐fold increase in NO production within APCs, which is known to be necessary for glycoantigen presentation on MHC class II. CGD mice exhibited increased Th1 pro‐inflammatory T‐cell responses in vitro and in vivo, characterized by more severe abscess pathology. This phenotype was also seen in WT animals following adoptive transfer of neutrophil‐depleted APCs from CGD animals, demonstrating that this phenotype was independent of neutrophil and T‐cell defects. Finally, pharmacological attenuation of NO production to WT levels in vivo reduced abscess incidence and severity in CGD without overt increases in inflammation or the ability to clear infection, suggesting a potential new treatment option for early stage CGD‐associated infections.
T‐zone localized monocyte‐derived dendritic cells promote Th1 priming to Salmonella
Authors: Flores‐Langarica Adriana , Marshall Jennifer L. , Bobat Saeeda , Mohr Elodie , Hitchcock Jessica , Ross Ewan A. , Coughlan Ruth E. , Khan Mahmood , Van Rooijen Nico , Henderson Ian R. , MacLennan Ian C.M. , Cunningham Adam F. 
Published: June 2011

AbstractControl of intracellular Salmonella infection requires Th1 priming and IFN‐γ production. Here, we show that efficient Th1 priming after Salmonella infection requires CD11c+CD11bhiF4/80+ monocyte‐derived dendritic cells (moDCs). In non‐infected spleens, moDCs are absent from T‐cell zones (T zones) of secondary lymphoid tissues, but by 24 h post‐infection moDCs are readily discernible in these sites. The accumulation of moDCs is more dependent upon bacterial viability than bacterial virulence. Kinetic studies showed that moDCs were necessary to prime but not sustain Th1 responses, while ex vivo studies showed that antigen‐experienced moDCs were sufficient to induce T‐cell proliferation and IFN‐γ production via a TNF‐α‐dependent mechanism. Importantly, moDCs and cDCs when co‐cultured induced superior Th1 differentiation than either subset alone, and this activity was independent of TNF‐α. Thus, optimal Th1 development to Salmonella requires the rapid accumulation of moDCs within T zones and their collaboration with cDCs.
Molecular Assemblies Based on Polytungstate Clusters and the Flexible Organic Ligand 1,3‐Bis(4‐pyridyl)propane
Authors: Han Zhangang , Wang Yanna , Song Xuejun , Zhai Xueliang , Hu Changwen 
Published: June 2011

AbstractFour polyoxometalate (POM) assemblies based on the flexible organic ligand 1,3‐bis(4‐pyridyl)propane (bpp) have been synthesized and fully characterized, including (Hbpp)3[PW12O40] (1), [Cu(bpp)]2[Cu2(bpp)3][SiW12O40] (2), [Cu2(Hbpp)4](H2bpp)0.5H2[SbW18O60]·3H2O (3), and (H2bpp)5[Ni4(OH2)2(AsW9O34)2]·0.5H2O (4). Compounds 1 and 2 were prepared by the reaction of the classical Keggin‐type anions with organic bpp under hydrothermal conditions. The difference between these compounds is that protonated bpp is found in 1, whereas in 2 CuI‐bpp fragments are present. In the framework of 1, organic and hybrid chains, built upon supramolecular interactions, coexist. Compound 2, which crystallizes in a chiral space group, has a 2D wave‐like structure consisting of {Cu6(bpp)6} grids that accommodate {[Cu2(bpp)2][SiW12O40]}2– fragments. The nonclassical anionic clusters in 3 and 4 are obtained from simple inorganic salts or oxides under hydrothermal conditions. The inorganic moiety in 3 exhibits a pseudo‐Dawson‐like [SbW18O60]9– cluster, and in 4 a sandwich‐type [Ni4(H2O)2(AsW9O34)2]10– anion is present. The organic ligand bpp, with a freely rotatable –(CH2)3– group, is present in various conformations in the four compounds. Structure‐analyses results indicate that the flexibility of bpp plays a significant role in the fabrication of these kinds of inorganic‐organic arrangements. The thermal and electrochemistry properties of all four compounds have also been studied.
Disorder in Rare Earth Metal Halide Carbide Nitrides
Authors: Schaloske Manuel C. , Kienle Lorenz , Mattausch Hansjürgen , Duppel Viola , Simon Arndt 
Published: June 2011

AbstractSingle‐crystal X‐ray structure determinations of Ce4I6CN and disordered Ce6I9C2N phases are described together with electron‐microscopy studies of Ce6I9C2N and Y6I9C2N. Ce4I6CN crystallizes in the tetragonal space group P42/mnm with a = 13.877(2) Å, c = 9.665(2) Å. Compounds β′‐Ce6I9C2N and β″‐Ce6I9C2N crystallize in space group P6/m with a = 41.774(6) Å, c = 13.719(3) Å and a = 20.958(3) Å, c = 13.793(3) Å, respectively. The main structural feature of these compounds are rods of RE6C2 octahedra and RE4N tetrahedra (RE = lanthanide) interconnected in different sequences. These rods are linked into Kagomé‐type frameworks with additional rods located in the centres of thehexagonal channels. The disorder patterns for these additional rods can be rationalized in terms of nearest‐neighbour interactions.