bluuebunny/crossref_metadata_2025_split huggingface dataset:
Supportive use of cyclodextrins as decontamination agents for herbicides: the case of fenoxaprop‐p‐ethyl
Authors: Petralito S. , Zanardi I. , Braconi D. , Santucci A. , Memoli A. , Caccamo E. , Travagli V. 
Published: July 2012

ABSTRACTThe inclusion complexes of herbicides in cyclodextrins (CDs) have been considered in an attempt to assess the potentiality of CDs as new formulation additives for both delivery improvement, and reduction of toxicity in terms of environmental impact.The aim of this work was to evaluate the role of three different types of CDs—namely β‐CD and its two derivatives, randomly methylated β‐CD and hydroxypropyl β‐CD—towards the herbicide fenoxaprop‐p‐ethyl (FE) properties. The toxicity of both pure FE (either alone or as inclusion complex) and a commercial product has been evaluated by an amperometric biosensor based on a Clark electrode as a respirometry study on Saccharomyces cerevisiae strain. Such a technique results more sensitive with respect to FE toxicity methods based on cell growth. The toxic effect of the commercial product was higher than that of the pure chemical entity. Photochemical studies on FE and FE‐CD complexes in the presence of different soil colloidal components showed the catalytic effect of some of CDs on photodegradation. The obtained results suggest that CDs could be useful excipients to promote enhancement of solubility, photodegradation inductive effect, and bioremediation in case of FE‐like hydrophobic herbicides. © 2012 Curtin University of Technology and John Wiley & Sons, Ltd.
A Series of Amino Acid Functionalized Tripodal Hexaamide Anion Receptors: Ion‐Pair‐Assisted Capped‐Cleft Formation by a Pentafluorophenyl‐Functionalized Amide
Authors: Bose Purnandhu , Ravikumar Iyyamperumal , Akhuli Bidyut , Ghosh Pradyut 
Published: July 2012

AbstractA new series of tris(2‐aminoethyl)amine (tren)‐based L‐alanine amino acid backboned tripodal hexaamide receptors (L1–L5) with various attached moieties based on electron‐withdrawing fluoro groups and lipophilicity have been synthesized and characterized. Detailed binding studies of L1–L5 with different anions, such as halides (F−, Cl−, Br−, and I−) and oxyanions (AcO−, BzO− (Bz=benzoyl), NO3−, H2PO4−, and HSO4−), have been carried out by isothermal titration calorimetric (ITC) experiments in acetonitrile/dimethylsulfoxide (99.5:0.5 v/v) at 298 K. ITC titration experiments have clearly shown that receptors L1–L4 invariably form 1:1 complexes with Cl−, AcO−, BzO−, and HSO4−, whereas L5 forms a 1:1 complex only with AcO−. In the case of Br−, I−, and NO3−, no appreciable heat change is observed owing to weak interactions between these anions and receptors; this is further confirmed by 1H NMR spectroscopy. The ITC binding studies of F− and H2PO4− do not fit well for a 1:1 binding model. Furthermore, ITC binding studies also revealed slightly higher selectivity of this series of receptors towards AcO− over Cl−, BzO−, and HSO4−. Solid‐state structural evidence for the recognition of Cl− by this new category of receptor was confirmed by single‐crystal X‐ray structural analysis of the complex of tetrabutylammonium chloride (TBACl) and L1. Single‐crystal X‐ray diffraction clearly showed that the pentafluorophenyl‐functionalized amide receptor (L1) encapsulated Cl− in its cavity by hydrogen bonds from amides, and the cavity of L1 was capped with a TBA cation through hydrogen bonding and ion‐pair interactions to form a capped‐cleft orientation. To understand the role of the cationic counterpart in solution‐state Cl− binding processes with this series of receptors (L1–L4), a detailed Cl− binding study was carried out with three different tetraalkylammonium (Me4N+, Et4N+, and Bu4N+) salts of Cl−. The binding affinities of these receptors with different tetralkylammonium salts of Cl− gave binding constants with the TBA cation in the following order: butyl>ethyl>methyl. This study further supports the role of the TBA countercation in ion‐pair recognition by this series of receptors.
From A Fluorescent Chromophore in Solution to An Efficient Emitter in the Solid State
Authors: Liu Yang , Lv Yun , Zhang Xiying , Chen Shuming , Lam Jacky W. Y. , Lu Ping , Kwok Ryan T. K. , Kwok Hoi Sing , Tao Xutang , Tang Ben Zhong 
Published: July 2012

AbstractPolycyclic aromatic hydrocarbons (PAHs) normally exhibit efficient fluorescence in dilute solutions, whereas their emission is significantly quenched in the aggregated state due to the formation of π‐aggregates/excimers. The rigid and planar structure of PAHs plays a positive role in terms of fluorescence in solution but a negative one in the aggregated state. To bestow PAHs a luminescent ability in the solid state, we constructed a non‐coplanar PAH‐substituted ethene. By using the planar PAH fluoranthene as a building block, a highly efficient solid‐state emitter with a fluorescence quantum efficiency of unity in the aggregated state was obtained. OLEDs with contain the molecule as an emitter reach a luminance up to 20 520 cd m−2 and an efficiency of 10 cd A−1.
Menin as a hub controlling mixed lineage leukemia
Authors: Thiel Austin T. , Huang Jing , Lei Ming , Hua Xianxin 
Published: July 2012

AbstractMixed lineage leukemia (MLL) fusion protein (FP)‐induced acute leukemia is highly aggressive and often refractory to therapy. Recent progress in the field has unraveled novel mechanisms and targets to combat this disease. Menin, a nuclear protein, interacts with wild‐type (WT) MLL, MLL‐FPs, and other partners such as the chromatin‐associated protein LEDGF and the transcription factor C‐Myb to promote leukemogenesis. The newly solved co‐crystal structure illustrating the menin–MLL interaction, coupled with the role of menin in recruiting both WT MLL and MLL‐FPs to target genes, highlights menin as a scaffold protein and a central hub controlling this type of leukemia. The menin/WT MLL/MLL‐FP hub may also cooperate with several signaling pathways, including Wnt, GSK3, and bromodomain‐containing Brd4‐related pathways to sustain MLL‐FP‐induced leukemogenesis, revealing new therapeutic targets to improve the treatment of MLL‐FP leukemias.
Synthesis and interaction of bovine serum albumin with p‐hydroxybenzoic acid derivatives
Authors: Zhang Xue‐Hong , Liu Li‐Na , Lin Yi‐Jie , Lin Cui‐Wu 
Published: July 2012

ABSTRACTThree novel p‐hydroxybenzoic acid derivatives (HSOP, HSOX, HSCP) were synthesized from p‐hydroxybenzoic acid and sulfonamides (sulfamonomethoxine sodium, sulfamethoxazole and sulfachloropyridazine sodium) and characterized by elemental analysis, HNMR and MS. Interactions between derivatives and bovine serum albumin (BSA) were studied by fluorescence quenching spectra, UV–vis absorption spectra and time‐resolved fluorescence spectra. Based on fluorescence quenching calculation and Förster's non‐radioactive energy transfer theory, the values of the binding constants, basic thermodynamic parameters and binding distances were obtained. Experimental results indicated that the three derivatives had a strong ability to quench fluorescence from BSA and that the binding reactions of the derivatives with BSA were a static quenching process. Thermodynamic parameters showed that binding reactions were spontaneous and exothermic and hydrogen bond and van der Waals force were predominant intermolecular forces between the derivatives and BSA. Synchronous fluorescence spectra suggested that HSOX and HSCP had little effect on the microenvironment and conformation of BSA in the binding reactions but the microenvironments around tyrosine residues were disturbed and polarity around tyrosine residues increased in the presence of HSOP. Copyright © 2012 John Wiley & Sons, Ltd.
Safety and cost-effectiveness of shortening hospital follow-up after breast cancer treatment
Authors: Lu W , Greuter M J W , Schaapveld M , Vermeulen K M , Wiggers T , de Bock G H 
Published: July 2012

Abstract

Background
In the Netherlands, the first 5 years of follow-up after treatment for breast cancer are carried out in hospital with yearly mammography. After this, for patients aged over 60 years who have undergone mastectomy, there is a shift of care to the National Screening Programme (NSP) for mammography every 2 years. After breast-conserving therapy follow-up is perfomed by the general practitioner (GP), with mammography every second year and physical examination annually. The aim of this study was to evaluate the clinical effects and costs of four different strategies for follow-up after breast cancer treatment.

Methods
An extended and validated simulation model for breast cancer follow-up was used. The current guidelines for follow-up (baseline strategy) and three less intensive follow-up strategies were evaluated. The main outcome measure was the detection rate of small tumours (2 cm or smaller) and associated costs for each strategy.

Results
Shortening the follow-up time in hospital by shifting care to the NSP or GP after 2 years instead of 5 years of hospital follow-up, lowering the age of referral to the NSP or GP from 60 to 50 years, and termination of annual physical examination by the GP after hospital follow-up did not decrease the detection of small tumours. In addition, a substantial decrease in costs was observed with simplified follow-up.

Conclusion
Decreasing hospital follow-up time, lowering the age of referral to the NSP or GP, and termination of annual physical examinations would lead to a substantial reduction in costs while maintaining the possibility of detecting small breast cancers.
Effects of low cardiopulmonary reserve on pancreatic leak following pancreaticoduodenectomy
Authors: Ausania F , Snowden C P , Prentis J M , Holmes L R , Jaques B C , White S A , French J J , Manas D M , Charnley R M 
Published: July 2012

AbstractBackgroundPostoperative complications are increased in patients with reduced cardiopulmonary reserve undergoing major surgery. Pancreatic leak is an important contributor to postoperative complications and death following pancreaticoduodenectomy. The aim of this study was to determine whether reduced cardiopulmonary reserve was a risk factor for pancreatic leak.MethodsAll patients who underwent pancreaticoduodenectomy between January 2006 and July 2010 were identified from a prospectively held database. Data analysis was restricted to those who underwent cardiopulmonary exercise testing during preoperative assessment. Pancreatic leak was defined as grade A, B or C according to the International Study Group on Pancreatic Fistula definition. An anaerobic threshold (AT) cut-off value of 10·1 ml per kg per min was used to identify patients with reduced cardiopulmonary reserve. Univariable and multivariable analyses were performed to identify other risk factors for pancreatic leak.ResultsSome 67 men and 57 women with a median age of 66 (range 37–82) years were identified. Low AT was significantly associated with pancreatic leak (45 versus 19·2 per cent in patients with greater cardiopulmonary reserve; P = 0·020), postoperative complications (70 versus 38·5 per cent; P = 0·013) and prolonged hospital stay (29·4 versus 17·5 days; P = 0·001). On multivariable analysis, an AT of 10·1 ml per kg per min or less was the only independent factor associated with pancreatic leak.ConclusionLow cardiopulmonary reserve was associated with pancreatic leak following pancreaticoduodenectomy. AT seems a useful tool for stratifying the risk of postoperative complications.
Randomized clinical trial of open hepatectomy with or without intermittent Pringle manoeuvre
Authors: Lee K F , Cheung Y S , Wong J , Chong C C , Wong J S , Lai P B 
Published: July 2012

Abstract

Background
The intermittent Pringle manoeuvre (IPM) is commonly applied during liver resection. Few randomized trials have addressed its effectiveness in reducing blood loss and the results have been conflicting. The present study investigated the hypothesis that IPM could reduce blood loss during liver resection by 50 per cent.

Methods
Between May 2008 and April 2011, patients who underwent elective open hepatectomy were randomized into an IPM or no Pringle manoeuvre (NPM) group and stratified according to the presence or absence of cirrhosis. Data on demographics, type of hepatectomy, operative blood loss, duration of operation, mortality, morbidity and postoperative liver function were recorded and analysed. The primary endpoint was operative blood loss.

Results
There were 63 patients in each group. Median (range) operative blood loss was 370 (50–3600) ml in the IPM group versus 335 (40–3160) ml in the NPM group (P = 1·000). There were no differences in blood loss in different phases of the operation, blood loss per area of liver transected or blood transfusion rate, nor in total duration of operation or liver transection time. Postoperative serum alanine aminotransferase levels were higher in the IPM group (P &lt; 0·001). There were more postoperative complications in the IPM group (41 versus 24 per cent; P = 0·036).

Conclusion
The IPM did not reduce blood loss, but was associated with raised levels of postoperative liver parenchymal enzymes and more complications. Registration number: NCT00730743 (http://www.clinicaltrials.gov).
Storage stability studies for tributyltin determination in human urine samples using headspace solid‐phase microextraction and gas chromatography mass spectrometry
Authors: Zachariadis G. A. , Tzollas N. M. , Nikolaou M. , Rosenberg E. 
Published: July 2012

ABSTRACTA headspace solid‐phase micro‐extraction (HS‐SPME) method was employed in order to study the effect of storage conditions of human urine samples spiked with tributyltin (TBT) using gas chromatography and mass spectrometry. To render the analyte more volatile, the derivatization (ethylation) was made in situ by sodium tetraethylborate (NaBEt4), which was added directly to dilute unpreserved urine samples and in buffers of similar acidity. The stability of TBT in human urine matrix was compared with the stability of TBT in buffer solutions of similar pH value. Critical parameters of storage conditions such as temperature and time, which affect the stability of TBT in this kind of matrix, were examined extensively. The tests showed that the stability of TBT remains practically satisfactory for a maximum of 2 days of storage either at +4 or 20°C. Greater variations were observed in the concentration of TBT in human urine samples at +4°C and lower ones at −20°C over a month's storage. The freeze–thaw cycles have negative effect on the stability and should be kept to a minimum. The results from spiked urine samples are also discussed in comparison to those acquired from buffer solutions of equal TBT concentration. Copyright © 2012 John Wiley & Sons, Ltd.
Coordinate regulation between expression levels of telomere‐binding proteins and telomere length in breast carcinomas
Authors: Butler Kimberly S. , Hines William C. , Heaphy Christopher M. , Griffith Jeffrey K. 
Published: July 2012

AbstractTelomere dysregulation occurs in both the in situ and invasive stages of many carcinomas, including breast. Knockout experiments have identified several telomere‐associated proteins required for proper telomere function and maintenance, including telomere repeat‐binding factor 1 and 2 (TRF1 and TRF2), protection of telomeres (POT1), and TRF1‐interacting nuclear factor 2 (TIN2). Using telomere content assays and quantitative reverse transcription‐polymerase chain reaction (RT‐PCR), we examined the relationship between telomere length and the mRNA levels of telomere‐associated proteins in breast tumors. The levels of TRF2, TRF1, TIN2, and POT1 mRNA, but not telomerase reverse transcriptase (TERT) RNA, are inversely correlated with telomere content in breast tumors. Significant associations were identified between the mRNA levels of TRF1, TIN2, and POT1; however, there were no significant associations with the mRNA levels of TRF2 or TERT. These associations suggest that a complex transcriptional program coordinately regulates the expression of these mRNAs. We examined the promoter regions of the telomere‐associated proteins to identify transcription factors consistent with the observed patterns of presumed coordinate expression. We demonstrated in human breast cancer cell lines that expressions of TRF1, TIN2, and POT1 are upregulated by dexamethasone, suggesting activation of the glucocorticoid receptor, whereas TERT, TRF2, TRF1, TIN2, and POT1 are upregulated by tumor necrosis factor‐α (TNF‐α), suggesting activation of the nuclear factor kappa B transcription factor. These findings link telomere content in breast tumors to the coordinate expression of several telomere‐associated proteins previously shown to be negative regulators of telomere length in cell lines. The results further suggest a possible link between the expressions of the telomere‐associated proteins and mediators of stress and inflammation.
From Monomers to π Stacks, from Nonconductive to Conductive: Syntheses, Characterization, and Crystal Structures of Benzidine Radical Cations
Authors: Chen Xiaoyu , Ma Binbin , Wang Xingyong , Yao Shengxin , Ni Lichen , Zhou Zhaoyi , Li Yizhi , Huang Wei , Ma Jing , Zuo Jinglin , Wang Xinping 
Published: July 2012

AbstractSalts that contain radical cations of benzidine (BZ), 3,3′,5,5′‐tetramethylbenzidine (TMB), 2,2′,6,6′‐tetraisopropylbenzidine (TPB), and 4,4′‐terphenyldiamine (DATP) have been isolated with weakly coordinating anions [Al(ORF)4]− (ORF=OC(CF3)3) or SbF6−. They were prepared by reaction of the respective silver(I) salts with stoichiometric amounts of benzidine or its alkyl‐substituted derivatives in CH2Cl2. The salts were characterized by UV absorption and EPR spectroscopy as well as by their single‐crystal X‐ray structures. Variable‐temperature UV/Vis absorption spectra of BZ.+[Al(ORF)4]− and TMB.+[Al(ORF)4]− in acetonitrile indicate an equilibrium between monomeric free radical cations and a radical‐cation dimer. In contrast, the absorption spectrum of TPB.+SbF6− in acetonitrile indicates that the oxidation of TPB only resulted in a monomeric radical cation. Single‐crystal X‐ray diffraction studies show that in the solid state BZ and its methylation derivative (TMB) form radical‐cation π dimers upon oxidation, whereas that modified with isopropyl groups (TPB) becomes a monomeric free radical cation. By increasing the chain length, π stacks of π dimers are obtained for the radical cation of DATP. The single‐crystal conductivity measurements show that monomerized or π‐dimerized radicals (BZ.+, TMB.+, and TPB.+) are nonconductive, whereas the π‐stacked radical (DATP.+) is conductive. A conduction mechanism between chains through π stacks is proposed.
High‐Generation Second‐Order Nonlinear Optical (NLO) Dendrimers that Contain Isolation Chromophores: Convenient Synthesis by Using Click Chemistry and their Increased NLO Effects
Authors: Wu Wenbo , Li Conggang , Yu Gui , Liu Yunqi , Ye Cheng , Qin Jingui , Li Zhen 
Published: July 2012

AbstractHerein, high‐generation dendrimers G4‐NS and G5‐NS, which contained 30 and 62 azo‐benzene chromophore moieties, respectively, were conveniently prepared in high purity and satisfied yields by a combination of divergent and convergent approaches, coupled with the utilization of the powerful Sharpless click reaction. These dendrimers possessed a regular structure of alternating layers of nitro‐based and sulfonyl‐based azo chromophores in which the sulfonyl‐based azo‐chromophore moieties were utilized as co‐isolation groups for the nitro‐based moieties to achieve larger macroscopic second‐order nonlinear optical (NLO) effects. These high‐generation dendrimers (G4‐NS and G5‐NS) displayed very large NLO efficiencies (up to 253.0 pm V−1), which is, to the best of our knowledge, the record highest efficiency for simple azo‐chromophore moieties.
Triaryl‐1,3,5‐triazinane‐2,4,6‐triones (Isocyanurates) Peripherally Functionalized by Donor Groups: Synthesis and Study of Their Linear and Nonlinear Optical Properties
Authors: Argouarch Gilles , Veillard Romain , Roisnel Thierry , Amar Anissa , Meghezzi Hacène , Boucekkine Abdou , Hugues Vincent , Mongin Olivier , Blanchard‐Desce Mireille , Paul Frédéric 
Published: July 2012

AbstractThe linear optical (LO) and nonlinear optical (NLO) properties of a series of isocyanurates functionalized by donor arms at the periphery are reported herein. These octupolar derivatives were obtained in a straightforward way from commercial isocyanate derivatives and were fully characterized. Although several of these compounds are known, those that exhibited the largest NLO activities are all new compounds. In terms of second‐order activity, several of these derivatives exhibit remarkable activity/transparency tradeoffs. In terms of third‐order activity, the longer derivatives with the stronger donor groups (X=NH2, NMe2, or NPh2) were shown to possess significant two‐photon absorption cross sections. These strongly luminescent derivatives exhibit two‐photon absorption cross sections up to 410 GM. DFT computations were also conducted to unravel their electronic structures and to rationalize their NLO properties. To our knowledge, the present study is the first concerned with the nonlinear optical properties of these original cyclotrimers.
Silver‐Catalysed Enantioselective Addition of OH and NH Bonds to Allenes: A New Model for Stereoselectivity Based on Noncovalent Interactions
Authors: Arbour Jannine L. , Rzepa Henry S. , Contreras‐García Julia , Adrio Luis A. , Barreiro Elena M. , Hii King Kuok (Mimi) 
Published: July 2012

AbstractThe ability of silver complexes to catalyse the enantioselective addition of OH and NH bonds to allenes is demonstrated for the first time by using optically active anionic ligands that were derived from oxophosphorus(V) acids as the sources of chirality. The intramolecular addition of acids, alcohols, and amines to allenes can be achieved with up to 73 % ee. The exploitation of a CH anomeric effect allowed the absolute configuration of a sample of 2‐substituted tetrahydrofuran of low ee to be unambiguously assigned by comparison of the chiroptical ORD and VCD measurements with calculated spectra. In the second part of the work, the origin of the stereoselectivity was probed by DFT free‐energy calculations of the transition states. A new model of enantiomeric differentiation was developed that was based on noncovalent interactions. This model allowed us to identify the source of stereoselectivity as weak attractive interactions; such dispersive forces are often overlooked in asymmetric catalysis. A new computational approach was developed that represents these interactions as colour‐coded isosurfaces that are characterised by the reduced density‐gradient profile.
Asymmetric Inverse‐Electron‐Demand Hetero‐Diels–Alder Reaction for the Construction of Bicyclic Skeletons with Multiple Stereocenters by Using a Bifunctional Organocatalytic Strategy: An Efficient Approach to Chiral Macrolides
Authors: Jiang Xianxing , Wang Long , Kai Ming , Zhu Liping , Yao Xiaojun , Wang Rui 
Published: July 2012

AbstractWe have performed the first bifunctional organocatalytic highly enantioselective inverse‐electron‐demand hetero‐Diels–Alder reaction of cyclic ketones with enones to afford densely functionalized bicyclic skeletons that contain three stereocenters (up 82 % yield, 10:1 d.r., and 97 % ee). Unlike the previous IEDDAR catalytic strategy, this method features a double HOMOdienophile/ LUMOdiene‐activated pathway. Moreover, this process provides a promising method for the construction of enantioenriched macrolides.