bluuebunny/crossref_metadata_2025_split huggingface dataset:
Topographical and ecohydrological controls on land surface temperature in an alpine catchment
Authors: Bertoldi G. , Notarnicola C. , Leitinger G. , Endrizzi S. , Zebisch M. , Della Chiesa S. , Tappeiner U. 
Published: May 2010

AbstractIn mountain areas, land surface temperature (LST) is a key parameter in the surface energy budget and is controlled by a complex interplay of topography, incoming radiation and atmospheric processes, as well as soil moisture distribution, different land covers and vegetation types. In this contribution, the LST spatial distribution of the Stubai Valley in the Austrian Alps is simulated by the ecohydrological model GEOtop. This simulation is compared with ground observations and a Landsat image in order to assess the capacity of the model to represent land surface interactions in complex terrain, as well as to evaluate the relative importance of different environmental factors. The model describes the energy and mass exchanges between soil, vegetation and atmosphere. It takes account of land cover, soil moisture and the implications of topography on air temperature and solar radiation. The GEOtop model is able to reproduce the spatial patterns of the LST distribution estimated from remote sensing, with a correlation coefficient of 0·88 and minimal calibration of the model parameters. Results show that, for the humid climate considered in this study, the major factors controlling LST spatial distribution are incoming solar radiation and land cover variability. Along mountain ridges and south‐exposed steep slopes, soil moisture distribution has only a minor effect on LST. North‐ and south‐facing slopes reveal a distinct thermal behaviour. In fact, LST appears to follow the air temperature vertical gradient along north‐facing slopes, while along south‐facing slopes, the LST vertical gradient is strongly modified by land cover type. Both Landsat observations and model simulations confirm field evidence of strong warming of alpine low vegetation during sunny days and indicate that these effects have an impact at a regional scale. Our results indicate that in order to simulate LST in mountain environments using a spatially distributed hydrological model, a key factor is the capacity to explicitly simulate the effects of complex topography on the surface energy exchange processes. Copyright © 2010 John Wiley & Sons, Ltd.
Spontaneous Resolution and Carbonation of Chiral Benzyllithium Complexes
Authors: Lennartson Anders , Sundberg Jonas , Wiklund Tove , Hilmersson Göran , Håkansson Mikael 
Published: May 2010

AbstractIn search for new examples of absolute asymmetric synthesis (AAS), chiral α‐substituted benzyllithium complexes have been prepared. While [Li(phet)(pmdta)] (1) (phet = 1‐phenylethyl, pmdta = N,N,N′,N″,N″‐pentamethyldiethylenetriamine) affords only racemic crystals, a promising candidate for AAS was indeed found: [Li(phet)(tmpda)], α‐2, (tmpda = N,N,N′,N′‐tetramethylpropylenediamine) crystallises as a conglomerate. Although concomitant polymorphism was not observed, a racemic phase (β‐2) could also be isolated. Chiral crystals of α‐2 gave 2‐phenylpropionic acid in high yield on reaction with gaseous CO2, but the bulk product was racemic. It is unclear whether the lack of selectivity originates during crystallisation or carbonation. In order to investigate this, similar complexes displaying Si or S atoms in the α‐position were prepared and structurally characterized: [Li(tmsb)(tmpda)] (tmsb = 1‐trimetylsilylbenzyl) (3), [Li{C(CH3)(Ph)(SPh)}(pmdta)] (4), [Li{C(CH3)(Ph)(SPh)}(tmeda)] (5), and [Li(tmeda)2][C(CH3)(Ph)(SPh)] (6). The introduction of heavy atoms should allow determination of absolute configuration and enantiopurity, but so far only racemic crystals have been obtained.
Polymorphism of Fluoroargentates(II): Facile Collapse of a Layered Network of α‐K2AgF4 Due to the Insufficient Size of the Potassium Cation
Authors: Kurzydłowski Dominik , Derzsi Marianna , Budzianowski Armand , Jagličić Zvonko , Koźmiński Wiktor , Mazej Zoran , Grochala Wojciech 
Published: May 2010

AbstractWe report the crystal structure and magnetic properties of a novel β polymorph of K2AgF4. β‐K2AgF4 is paramagnetic above 20 K and exhibits a low Curie temperature (θ < 5 K). Solid state DFT (GGA and GGA+U) calculations were performed to analyze the electronic and magnetic structure of β‐K2AgF4 at 0 K/0 GPa, reproducing correctly the ferromagnetic (FM) semiconductor ground state with the band gap at the Fermi level of approximately 1.65 eV. Furthermore, we show that the novel β form is thermodynamically favoured over the previously reported two‐dimensional α form and can be formed either by slow spontaneous exothermic α to β phase transition occurring on heating or direct synthesis from KF and AgF2 at 300 °C. The relative stability of the α and β phases is rationalized in terms of the size of the M+ cation in the M2M′F4 series (M = Na, K, Cs, M′ = Cu, Ag) and the mismatch between [MF] and [M′F4/2] sublattices in the layered perovskite α form.
Disilver(I) Coordination Complexes: Synthesis, Reaction Chemistry, and Their Potential Use in CVD and Spin‐Coating Processes for Silver Deposition
Authors: Jakob Alexander , Rüffer Tobias , Schmidt Heike , Djiele Patrice , Körbitz Kathrin , Ecorchard Petra , Haase Thomas , Kohse‐Höinghaus Katharina , Frühauf Swantje , Wächtler Thomas , Schulz Stefan , Gessner Thomas , Lang Heinrich 
Published: May 2010

AbstractThe synthesis of complexes [Ag2X] [X = O2CCO2 (3a), C4O4 (3b), O2CCH2CO2 (3c), O2C(CH2)2CO2 (3d), cis‐O2CCH=CHCO2 (3e), trans‐O2CCH=CHCO2 (3f), para‐O2CC6H4CO2 (3g)] and [(R3P)mAgXAg(PR3)m] [R = Ph, X = C4O4, m = 2 (10a), m = 3 (10b); R = nBu, X = O2CCH2CO2, m = 2 (10c), m = 3 (10d); X = O2C(CH2)2CO2, m = 1 (10e), m = 2 (10f), m = 3 (10g); X = cis‐O2CCH=CHCO2, m = 1 (10h), m = 2 (10i), m = 3 (10j); X = trans‐O2CCH=CHCO2, m = 1 (10k), m = 2 (10l), m = 3 (10m); X = para‐O2CC6H4CO2, m = 2 (10n)] is reported. Compoundds 3a–3g are accessible by the reaction of [AgNO3] (1) with H2X (2a–2g), while 10a–10n can be prepared by treatment of 3a–3g with PR3 (9a, R = Ph; 9b, R = nBu) in the ratios of 1:2, 1:4, or 1:6. When [{Ag(bipym)(NO3)·H2O}n] (6) (bipym = bipyrimidine) reacts with (HNEt3)2(O2CCO2) (7), [{Ag(bipym)Ag(O2CCO2)·4H2O}n] (5) and [{(bipym)(Ag(O2CCO2H))2}n] (8) are formed. The molecular structures for 5, 6, and 8 in the solid state are reported. For 5, the formation of a 3D network is characteristic, in which 1D chains of {Ag(bipym)Ag(O2CCO2)}n interact with each other through π–π interactions between the bipym ligands to extend in one direction, while H2O molecules act as connectivities thorugh the intermolecular H‐bridge formation to extend in the other direction. Polymeric 6 consists of 2D layers formed by individual 1D chains of {Ag(bipym)Ag(bipym)}n with π–π interactions between the bipym ligands. In 8, {(HO2CCO2)Ag(bipym)Ag(O2CCO2H)} units undergo intermolecular H‐bridge formation to create 2D layers, π–π interactions between individual bipym ligands produce a 3D network. The use of 10d as a CVD precursor in the deposition of Ag on glass by using a direct liquid injection system is discussed. The Ag films show a rough appearance and contain C impurities. The use of 10e and 10f as spin‐coating precursors for the deposition of Ag on TiN‐coated oxidized Si wafers is reported.
Nanostructures of Metal Tellurides (PbTe, CdTe, CoTe2, Bi2Te3, and Cu7Te4) with Various Morphologies: A General Solvothermal Synthesis and Optical Properties
Authors: Jiang Ling , Zhu Ying‐Jie , Cui Jing‐Biao 
Published: May 2010

AbstractA general surfactant‐assisted solvothermal route was developed for the synthesis of a variety of metal telluride nanostructures. In this method, a corresponding metal salt,Na2TeO3, ascorbic acid, and polyvinyl pyrrolidone (PVP) were used as reagents and a mixture of ethylene glycol (EG) and water was used as the solvent. The synthesis of nanostructures including PbTe, CdTe, CoTe2, Bi2Te3, and Cu7Te4 with varied morphologies was demonstrated by using this general approach. The mechanisms of formation of thesetelluride nanostructures are discussed. The optical properties including UV/Vis absorption of Cu7Te4 and CdTe and photoluminescence of CoTe2 nanostructures are investigated.
The Advantage of Covalent Capture in the Combinatorial Screening of a Dynamic Library for the Detection of Weak Interactions
Authors: Martin Marco , Gasparini Giulio , Graziani Matteo , Prins Leonard J. , Scrimin Paolo 
Published: May 2010

AbstractIn this paper we address the advantage of screening a dynamic library by covalent capture in comparison with an approach in which the target is not covalently bound to the molecular receptor. The aim is the selection of recognition units for the binding of an anion (or polyanion) by relatively weak binding interactions, a situation typically found in supramolecular chemistry. To compare the two approaches, two model systems have been studied both based on the functionalization of a molecular platform by reversible imine formation. In the case of the noncovalently bound substrate, the platform P1 is a trisubstituted benzene unit, 2,4,6‐trimethylbenzene‐1,3,5‐tricarbaldehyde, to select three recognition arms for the binding of the trisodium salt of benzene‐1,3,5‐tricarboxylate. For the covalent‐capture‐based approach the platforms P2 and P4 are benzene derivatives with a tethered phosphonate target (tetrabutylammonium 2‐formylphenyl ethylphosphonate) for the selection of a single recognition unit. The library of recognition elements comprises phenyl‐ and ammonium‐functionalized amines. We show that the selection of recognition units for the binding of the substrate with weak to medium binding constants may encounter, by using a noncovalently bound substrate, serious problems. This is because the best conditions for the amplification of the library, that is, a large excess of variable recognition elements and target, lead also to competitive binding of the elements not bound to the platform with the target. This may result in negligible amplification of the best‐fit members of the library. In contrast, upon tethering the target to the platform and using the covalent‐capture strategy for the selection of the recognition elements, significant amplification is observed, even for systems with much lower binding constants. Although competition with excess recognition units may also become an issue in the case of the tethered target, there is a way to overcome the problem by working at low concentrations.
C–N Bond Formation Catalysed by CuI Bonded to Polyaniline Nanofiber
Authors: Arundhathi Racha , Kumar Desitti Chaitanya , Sreedhar Bojja 
Published: May 2010

AbstractPolyaniline nanofiber as a macroligand for the supportedcuprous iodide catalyst (CuI‐PANInf) has been developed for the coupling of aryl halides (including aryl chlorides) with aliphatic, aromatic, and N(H)‐heterocyclic amines under ambient conditions (80 °C for aryl chlorides) has been developed. This simple and efficient method for coupling reactions is highly versatile, convenient, and also the catalyst can be used for several cycles with good‐to‐excellent yields.
Domino [3+3] Annulation/Ring‐Cleavage Reactions of 1,3‐Bis(trimethylsilyloxy)‐1,3‐butadienes with 5‐Aryl‐ and 5‐Vinyl‐3‐acyl‐ 4,5‐dihydrofurans: Efficient Synthesis of 5‐(4‐Chlorobut‐2‐en‐1‐yl)‐ and 5‐(2‐Aryl‐2‐chloroethyl)salicylates
Authors: Lau Matthias , Sher Muhammad , Villinger Alexander , Fischer Christine , Langer Peter 
Published: May 2010

AbstractThe domino “[3+3] cyclization–ring‐opening” reactions of 1,3‐bis(trimethylsilyloxy)‐1,3‐butadienes with 3‐acetyl‐5‐vinyl‐4,5‐dihydrofurans afforded 5‐(4‐halobut‐2‐en‐1‐yl)salicylates. The reactions of 1,3‐bis(trimethylsilyloxy)‐1,3‐butadienes with 3‐acetyl‐5‐aryl‐4,5‐dihydrofurans gave 5‐(2‐aryl‐2‐chloroethyl)salicylates.
One‐Pot Syntheses of α,β‐Unsaturated Carbonyl Compounds through Palladium‐Mediated Dehydrogenation of Ketones, ­Aldehydes, Esters, Lactones and Amides
Authors: Muzart Jacques 
Published: May 2010

AbstractThis review highlights the different direct stoichiometric and catalytic palladium procedures leading to α,β‐unsaturated carbonyl compounds from the corresponding ketones, aldehydes, esters, lactones and amides. The proposed mechanisms are described, in some cases with personal observations.
Efficient Sonogashira Coupling of Unprotected Halonucleosides in Aqueous Solvents Using Water‐Soluble Palladium Catalysts
Authors: Cho Joon Hyung , Prickett Caitlin D. , Shaughnessy Kevin H. 
Published: May 2010

AbstractA variety of applications of C‐alkynylated nucleosides has prompted the continuing development of efficient synthetic methods for their preparation. We report an efficient andenvironmentally benign Sonogashira coupling reaction for alkynylation of unprotected halonucleosides in an aqueous solvent. The combination of Pd(OAc)2, CuI, and TXPTS [trisodium tri(2,4‐dimethyl‐5‐sulfonatophenyl)phosphane] provided an effective catalyst for the alkynylation of 8‐bromopurines and 5‐iodouridine in H2O/CH3CN (1:1) in yields ranging from 42 to 98 %.
Metabolites from the Mangrove Endophytic Fungus Phomopsis sp. (#zsu‐H76)
Authors: Yang Jianxiang , Xu Fang , Huang Caihuan , Li Jing , She Zhigang , Pei Zhong , Lin Yongcheng 
Published: May 2010

AbstractThree unique metabolites, namely, phomopsis‐H76 A (1), B (2), and C (3), were isolated from the mangrove endophytic fungus Phomopsis sp. (#zsu‐H76). Structures were determined by spectroscopic methods, mainly 1D and 2D NMR spectroscopy. Compound 1–3 are all dimers. Compounds 2 and 3 possesses a pyrano[4,3‐b]pyran‐5(2H)‐one ring system that is unprecedented in nature. Primary bioassays showed that 1 accelerated the growth of subintestinal vessel plexus (SIV) branch markedly, whereas 3 showed inhibition of SIV. Compounds 1–3 showed no activity in antibacterial and cytotoxic tests.
Chiral Triphenylprolinol Ligands for the Efficient Catalytic Asymmetric Arylation of Aldehydes
Authors: Moro Angélica Venturini , Tiekink Edward R. T. , Zukerman‐Schpector Julio , Lüdtke Diogo S. , Correia Carlos Roque D. 
Published: May 2010

AbstractThe synthesis of new chiral amino alcohols by Heck arylation of an enecarbamate is described. These compounds were used as chiral ligands for the catalytic asymmetric arylation of aldehydes and can be easily recovered. Chiral, nonracemic diarylmethanols were obtained in high yields and enantioselectivities.
The Effect of Bulky Substituents on the Formation of Symmetrically Trisubstituted Triptycenes
Authors: Chmiel Jasmin , Heesemann Ingo , Mix Andreas , Neumann Beate , Stammler Hans‐Georg , Mitzel Norbert W. 
Published: May 2010

AbstractA series of 1,8‐dichloroanthracene precursor molecules with substituents in C‐10 position of different steric demand (cyclohexyl, tert‐butyl, methyl, isopropyl, n‐butyl, phenyl, benzyl, trimethylsilylethinyl) were synthesised and subjected to electrocyclic cycloadditions with chlorobenzyne generated from 3‐chloroanthranilic acid. The aim was to steer the regioselectivity of the addition reaction by the steric repulsion between this C‐10 substituent and the chlorine substituent at the benzyne intermediate. With H as C‐10 substituent the reaction leads to 23 % syn and 77 % anti form. With the small methyl group a syn/anti ratio of 37:63 was achieved. Contrary to our expectations the large C‐10 substituent tert‐butyl leads to 100 % selectivity for the anti form. The best results were achieved for the C‐10 substituent n‐butyl with a syn/anti ratio of 40:60. The crystal structures of five 1,8‐dichloroanthracenes with C‐10 substituents were determined, namely those with tert‐butyl, cyclohexyl, n‐butyl and phenyl groups. As expected the backbone of the tert‐butyl compound shows marked distortion of the planarity. Additionally, the crystal structures of three triptycenes were determined, namely those of the syn compound 1,8,13‐trichlorotriptycene and those of the anti compounds 10‐tert‐butyl‐1,8,16‐trichlorotriptycene and 1,8,16‐trichloro‐10‐methyltriptycene.
Feasibility of reirradiation of recurrent sinonasal carcinoma in the periorbital region using hypofractionated image‐guided intensity‐modulated radiation therapy
Authors: Thiagarajan Anuradha , Mechalakos James , Lee Nancy 
Published: May 2010

AbstractBackgroundRecurrent periorbital tumors pose management challenges because they are often unresectable and chemorefractory. Proximity to critical structures renders reirradiation difficult. With image‐guided intensity‐modulated radiation therapy (IG‐IMRT), real‐time corrections to patient setup are possible, enabling significant shrinkage of planning target volume margins and safe dose escalation with hypofractionation. Here, we present our experience with hypofractionated IG‐IMRT in a patient with multiply recurrent sinonasal carcinomas in the periorbital region.MethodsThe patient is a 67‐year‐old woman with sinonasal carcinoma, treated with surgery and 2 prior courses of high‐dose radiotherapy. She developed a second tumor recurrence in the right lateral orbit, which was reirradiated using hypofractionated IG‐IMRT (24 Gy in 3 fractions).ResultsNear‐complete resolution of her ocular symptoms was observed at 4 months. Progress scans demonstrated a decrease in size of the orbital lesion.ConclusionPreliminary results of reirradiation using hypofractionated IG‐IMRT suggest that it is safe and effective. © 2010 Wiley Periodicals, Inc. Head Neck, 2010
Long‐term results of 28 esthesioneuroblastomas managed over 35 years
Authors: de Gabory Ludovic , Abdulkhaleq Habib Merza , Darrouzet Vincent , Bébéar Jean‐Pierre , Stoll Dominique 
Published: May 2010

AbstractBackgroundThe purpose of our study was to assess the long‐term results in the management of patients with esthesioneuroblastoma.MethodsA total of 28 patients were retrospectively reviewed to analyze their clinical features, treatment outcomes, pattern of failures, and course of the disease.ResultsThe patients were classified as 2 patients with T1, 10 patients with T2, 10 patients with T3, and 6 patients with T4; the results of all were included in this study. Twenty‐six patients underwent surgery and 23 had postoperative radiotherapy over the tumor bed, only 9 had radiotherapy over the nodes. The average follow‐up was 99.11 months. Fifteen‐year and 20‐year disease‐specific and disease‐free survival rates were 88.6% to 66.4% and 59.6% to 29.8%, respectively. Six patients had recurrences and 60% of them occurred more than 10 years after treatment. In the first decade, nodal recurrences appeared earlier than local ones when patients with N0 did not undergo neck irradiation.ConclusionSurgery on patients with T presentations and adjuvant radiotherapy on T and N0 neck presentations seem to be essential to treat esthesioneuroblastoma. A follow‐up for a minimum of 20 years is necessary to ensure complete cure. © 2010 Wiley Periodicals, Inc. Head Neck, 2011
Localization and identification of parapharyngeal metastases from differentiated thyroid carcinoma by 131I‐SPECT/CT
Authors: Qiu Zhong‐Ling , Xu Yan‐Hong , Song Hong‐Jun , Luo Quan‐Yong 
Published: May 2010

AbstractBackgroundParapharyngeal metastasis is a rare event in differentiated thyroid carcinoma (DTC). The 131I‐single photon emission CT (SPECT)/CT allows better localization and definition for metastases in DTC. The aim of this study was to assess the value of 131I‐SPECT/CT for the diagnosis of parapharyngeal metastasis in patients with DTC.MethodsConsecutive patients with DTC (n = 561) treated with 131I for the ablation of remnant or treatment of metastases were enrolled. A 131I‐SPECT/CT was performed when there were abnormal findings indicative of parapharyngeal metastasis on 131I‐whole‐body scan (WBS).ResultsA total of 15 lesions were found to be parapharyngeal metastasis in 14 of 561 patients with DTC after the use of 131I‐SPECT/CT. The incidence rate of parapharyngeal metastasis was about 2.5% in DTC. Of the 15 lesions, only 5 lesions were CT‐positive. The remaining 10 lesions were either ignored or indeterminate by the CT alone.ConclusionThe 131I‐SPECT/CT can identify parapharyngeal metastasis at an early stage. Parapharyngeal metastasis in DTC is relatively frequent after the use of 131I‐SPECT/CT. © 2010 Wiley Periodicals, Inc. Head Neck, 2011
Increased radiation sensitivity of head and neck squamous cell carcinoma with sphingosine kinase 1 inhibition
Authors: Sinha Uttam K. , Schorn Victor J. , Hochstim Christian , Chinn Steven B. , Zhu Sutao , Masood Rizwan 
Published: May 2010

AbstractBackgroundSphingosine kinase 1 (SphK1) is an important regulator of apoptosis, survival, and proliferation in cancer cells. SphK1 expression in head and neck squamous cell cancer (HNSCC) cell lines and tumor tissue was assessed, and the efficacy of SphK1 knockdown in increasing tumor radiosensitivity was evaluated in vitro and in vivo.MethodsExpression of SphK1 was determined by immunohistochemistry, Western blot, and real‐time polymerase chain reaction (RT‐PCR) in 34 prospectively collected HNSCC tumor samples. HNSCC cell lines squamous cell carcinoma (SCC)‐15 and SCC‐25 were treated with SphK1 inhibitor SKI‐II and siRNA targeting SphK1 with and without radiation, and the cell viability was assessed. SCC‐15 cells with and without transfection of SphK1 siRNA were then injected into athymic nude mice to develop tumor xenografts, and these 2 groups were further divided into 1 group that received radiation and 1 group that did not. Tumor size was measured over 18 days, when the animals were killed and the tumors were evaluated by immunohistochemistry.ResultsSphK1 is found in both HNSCC cell lines and human tumor samples, with higher expression correlated with advanced tumor stage, nodal involvement, and recurrence. In vitro, both SCC‐15 and SCC‐25 were found to be radioresistant; however, they were sensitized by administration of SKI‐II and transfection with siRNA targeting SphK1. In vivo, SphK1‐siRNA transfected xenografts were decreased in size compared with both nonradiated control and radiated control mice, whereas mice with both SphK1‐siRNA and radiation treatment showed a synergistic reduction in tumor volume. Histopathologic analysis demonstrated a decreased proliferative state in SphK1‐siRNA transfected tumors.ConclusionSphK1 is upregulated in HNSCC, and inhibition of SphK1 sensitizes HNSCC to radiation‐induced cytotoxicity. © 2010 Wiley Periodicals, Inc. Head Neck, 2011
Immunoregulatory properties of CD44+ cancer stem‐like cells in squamous cell carcinoma of the head and neck
Authors: Chikamatsu Kazuaki , Takahashi Goro , Sakakura Koichi , Ferrone Soldano , Masuyama Keisuke 
Published: May 2010

AbstractBackgroundCD44 was found as a surface marker in cancer stem cell (CSC) of squamous cell carcinoma of the head and neck (SCCHN); however, the immunologic properties of such CSCs have not yet been elucidated.MethodsThe immunologic properties of CD44+ cancer stem‐like cells were compared with those of CD44‐ cells using flow cytometry and enzyme‐linked immunosorbent assay.ResultsCD44+ cells exhibited weak HLA‐A2 and class II expression. Interestingly, downregulation of transporter antigen processing (TAP)2 was found in CD44+ cells. The CD44+ cell population produced significantly higher levels of interleukin (IL)‐8, granulocyte colony‐stimulating factor (G‐CSF), and transforming growth factor (TGF)‐β than the CD44‐ cell population. Moreover, CD44+ cells have been shown to not only more strongly inhibit T‐cell proliferation, but also to more efficiently inhibit regulatory T cells (Treg cells) and myeloid‐derived suppressor cells (MDSC) as compared with CD44‐ cells. Additionally, CD44+ cells suppressed Th1 responses and enhanced regulatory T cell responses.ConclusionCSCs might have higher malignant potential with numerous escape strategies from immune attack. © 2010 Wiley Periodicals, Inc. Head Neck, 2011