bluuebunny/crossref_metadata_2025_split huggingface dataset:
The Registry Index: A Quantitative Measure of Materials′ Interfacial Commensurability
Authors: Hod Oded 
Published: June 2013

AbstractNanoscale tribology is an active and rapidly developing area of research that poses fundamental scientific questions that, if answered, may offer great technological potential in the fields of friction, wear, and lubrication. When considering nanoscale material′s junctions, surface commensurability often plays a crucial rule in dictating the tribological properties of the interface. This Review surveys recent theoretical work in this area, with the aim of providing a quantitative measure of the crystal lattice commensurability at interfaces between rigid materials and relating it to the tribological properties of the junction. By considering a variety of hexagonal layered materials, including graphene, hexagonal boron nitride, and molybdenum disulfide, we show how a simple geometrical parameter, termed the “registry index” (RI), can capture the interlayer sliding energy landscape as calculated using advanced electronic structure methods. The predictive power of this method is further demonstrated by showing how the RI is able to fully reproduce the experimentally measured frictional behavior of a graphene nanoflake sliding over a graphite surface. It is shown that generalizations towards heterogeneous junctions and non‐planar structures (e.g., nanotubes) provide a route for designing nanoscale systems with unique tribological properties, such as robust superlubricity. Future extension of this method towards nonparallel interfaces, bulk‐material junctions, molecular surface diffusion barriers, and dynamic simulations are discussed.
Structural Transformation of Bovine Serum Albumin Induced by Dimethyl Sulfoxide and Probed by Fluorescence Correlation Spectroscopy and Additional Methods
Authors: Pabbathi Ashok , Patra Satyajit , Samanta Anunay 
Published: June 2013

AbstractDetermining the structure of a protein and its transformation under different conditions is key to understanding its activity. The structural stability and activity of proteins in aqueous–organic solvent mixtures, which is an intriguing topic of research in biochemistry, is dependent on the nature of the protein and the properties of the medium. Herein, the effect of a commonly used cosolvent, dimethyl sulfoxide (DMSO), on the structure and conformational dynamics of bovine serum albumin (BSA) protein is studied by fluorescence correlation spectroscopy (FCS) measurements on fluorescein isothiocyanate (FITC)‐labeled BSA. The FCS study reveals a change of the hydrodynamic radius of BSA from 3.7 nm in the native state to 7.0 nm in the presence of 40 % DMSO, which suggests complete unfolding of the protein under these conditions. Fluorescence self‐quenching of FITC has been exploited to understand the conformational dynamics of BSA. The time constant of the conformational dynamics of BSA is found to change from 35 μs in its native state to 50 μs as the protein unfolds with increasing DMSO concentration. The FCS results are corroborated by the near‐UV circular dichroism spectra of the protein, which suggest a loss of its tertiary structure with increasing concentration of DMSO. The intrinsic fluorescence of BSA and the fluorescence response of 1‐anilinonaphthalene‐8‐sulfonic acid, used as a probe molecule, provide information that is consistent with the FCS measurements, except that aggregation of BSA is observed in the presence of 40 % DMSO in the ensemble measurements.
An Electrochemical and Raman Spectroscopy Study of the Surface Behaviour of Mononuclear Ruthenium and Osmium Polypyridyl Complexes Based on Pyridyl‐ and Thiophene‐Based Linkers
Authors: Halpin Yvonne , Logtenberg Hella , Cleary Laura , Schenk Stephan , Schulz Martin , Draksharapu Apparao , Browne Wesley R. , Vos Johannes G. 
Published: June 2013

AbstractThe utility of a thiophene anchor unit as an alternative for thiols in the immobilisation of ruthenium and osmium complexes on gold and platinum is examined with special attention focused on the relative contributions of physi‐ and chemisorption of the complexes and the chemical stability of the thiophene anchoring unit. The redox and spectroscopic properties of the ruthenium(II) and osmium(II) complexes are described in solution and the effect of surface immobilisation examined through a combined electrochemical and surface‐enhanced Raman spectroscopic study. A key finding is that although the thiophene unit is involved in surface anchoring it also undergoes chemical reactions with the gold surface as demonstrated by Raman spectroscopy.
2,2′‐Bis‐azonia‐Cope Rearrangements of 2,3‐Homo‐6H‐1,4‐diazepinium Dications
Authors: Quast Helmut , Seidenspinner Hubert‐Matthias , Stawitz Josef Walter 
Published: June 2013

AbstractThe condensation of cis‐1,2‐cyclopropanediamines with 1,3‐dicarbonyl compounds and 1,5‐diazapentadienium salts afforded 2,3‐homo‐1H‐1,4‐diazepinium salts, which were protonated by very strong acids to yield 2,3‐homo‐6H‐1,4‐diazepinium dications. As measures of basicity, the mole fractions of water in trifluoromethanesulfonic acid at half‐protonation were determined for 2,3‐homo‐ and 2,3‐dihydro‐1H‐1,4‐diazepinium salts. 2,3‐Homo‐6H‐1,4‐diazepinium dications underwent 2,2′‐bis‐azonia‐Cope rearrangements, as can be inferred from the product structures, or H/D exchange involving the methylene group of the cyclopropane rings. Apparently, in the Cope rearrangement, this group is interchanged with the methylene group in the seven‐membered ring (C‐6), which is susceptible to H/D exchange in strong deuteriated acids. Rapid, degenerate, as well as very slow, strongly biased Cope rearrangements have been uncovered in this way. 1H NMR spectra, recorded at elevated temperatures for a solution of the parent dication in trifluoromethanesulfonic acid, reveal broadening of the interchanging 2‐H, 3‐H and 5‐H, 7‐H signals and eventually the onset of their coalescence. Surprisingly, the estimated free enthalpy of activation is higher (ΔG‡110 °C ≈ 73 ± 2 kJ/mol) than that of 3,4‐homotropilidene (ΔG‡110 °C = 61 kJ/mol), not lower, as would be expected on the basis of the well‐known charge‐acceleration of Cope rearrangements.
Copper‐Catalyzed Synthesis of a Highly Hydroxy‐Functionalized Benzo[e]indolizidine by Intramolecular N‐Arylation
Authors: Cordero Franca M. , Khairnar Bhushan B. , Bonanno Paola , Martinelli Andrea , Brandi Alberto 
Published: June 2013

AbstractThe enantiopure (2S,3S,3aS,5S)‐1,2,3,3a,4,5‐hexahydropyrrolo[1,2‐a]quinoline‐2,3,5‐triol (2,3,5‐trihydroxybenzo[e]indolizidine) framework has been synthesized by a straightforward strategy consisting of 1,3‐dipolar cycloaddition of a pyrroline N‐oxide to 2‐bromostyrene followed by isoxazolidine N–O bond reduction and cyclization by copper‐catalyzed nucleophilic aromatic substitution of the intermediate pyrrolidine.
Bifunctional Squaramide‐Catalyzed One‐Pot Sequential Michael Addition/Dearomative Bromination: Convenient Access to Optically Active Brominated Pyrazol‐5(4H)‐ones with Adjacent Quaternary and Tertiary Stereocenters
Authors: Wang Huanxia , Wang Youming , Song Haibin , Zhou Zhenghong , Tang Chuchi 
Published: June 2013

AbstractThe organocatalytic asymmetric, one‐pot, sequential Michael addition/dearomative bromination reaction of pyrazol‐5‐ones to nitro olefins and N‐bromosuccinimide (NBS) has been developed. Under the catalysis of a chiral bifunctional squaramide, a wide variety of chiral brominated pyrazol‐5‐one derivatives with contiguous quaternary and tertiary stereocenters was obtained in high yields (up to >99 %) with good to excellent diastereoselectivities (62:38–99:1 dr) and uniformly high levels of enantioselectivity (92 to >99 % ee). This experimentally simple process facilitates access to various enantioenriched, multiply substituted pyrazolin‐5‐one derivatives, potential biologically active molecules, starting from readily available starting materials.
Retracted: Copper‐Catalyzed Synthesis of Substituted Isoindolo[2,1‐a]quinoxalines and Isoindolo[2,1‐a]quinoxalin‐6(5H)‐ones
Authors: Biswas Subhasish , Batra Sanjay 
Published: June 2013

AbstractAn operationally simple and efficient cascade strategy has been developed to access substituted isoindolo[2,1‐a]quinoxalines through a one‐step copper‐catalyzed C–N coupling reaction between substituted 2H‐isoindole‐1‐carbaldehydes and substituted 2‐halophenylamines. Another straightforward procedure is described to prepare substituted isoindolo[2,1‐a]quinoxalin‐6(5H)‐ones, which involved the transformation of a substituted 2H‐isoindole‐1‐carboxylic acid into an acid chloride followed by a coupling reaction with a substituted 2‐iodophenylamine and a copper‐catalyzed C–N coupling reaction.
Catalytic Asymmetric Allylic Alkylation of 3‐Arylated Piperidin‐2‐ones
Authors: Michon Christophe , Béthegnies Aurélien , Capet Frédéric , Roussel Pascal , de Filippis Arnault , Gomez‐Pardo Domingo , Cossy Janine , Agbossou‐Niedercorn Francine 
Published: June 2013

AbstractThe preparation of optically active lactams from 3‐aryl‐2‐piperidinone is reported. The quaternary carbon stereocentres were formed using palladium‐catalysed asymmetric allylic alkylation reactions. The resulting enantioenriched compounds are useful intermediates for the synthesis and development of neurokinin antagonists.
Appropriate viscous damping for nonlinear time‐history analysis of base‐isolated reinforced concrete buildings
Authors: Pant Deepak R. , Wijeyewickrema Anil C. , ElGawady Mohamed A. 
Published: June 2013

SUMMARYThere is no consensus at the present time regarding an appropriate approach to model viscous damping in nonlinear time‐history analysis of base‐isolated buildings because of uncertainties associated with quantification of energy dissipation. Therefore, in this study, the effects of modeling viscous damping on the response of base‐isolated reinforced concrete buildings subjected to earthquake ground motions are investigated. The test results of a reduced‐scale three‐story building previously tested on a shaking table are compared with three‐dimensional finite element simulation results. The study is primarily focused on nonlinear direct‐integration time‐history analysis, where many different approaches of modeling viscous damping, developed within the framework of Rayleigh damping are considered. Nonlinear direct‐integration time‐history analysis results reveal that the damping ratio as well as the approach used to model damping has significant effects on the response, and quite importantly, a damping ratio of 1% is more appropriate in simulating the response than a damping ratio of 5%. It is shown that stiffness‐proportional damping, where the coefficient multiplying the stiffness matrix is calculated from the frequency of the base‐isolated building with the post‐elastic stiffness of the isolation system, provides reasonable estimates of the peak response indicators, in addition to being able to capture the frequency content of the response very well. Furthermore, nonlinear modal time‐history analyses using constant as well as frequency‐dependent modal damping are also performed for comparison purposes. It was found that for nonlinear modal time‐history analysis, frequency‐dependent damping, where zero damping is assigned to the frequencies below the fundamental frequency of the superstructure for a fixed‐base condition and 5% damping is assigned to all other frequencies, is more appropriate, than 5% constant damping. Copyright © 2013 John Wiley & Sons, Ltd.
Development and validation of a quantitative structure–activity relationship for chronic narcosis to fish
Authors: Claeys Lieve , Iaccino Federica , Janssen Colin R. , Van Sprang Patrick , Verdonck Frederik 
Published: June 2013

Abstract

Vertebrate testing under the European Union's regulation on Registration, Evaluation, Authorisation and Restriction of Chemical substances (REACH) is discouraged, and the use of alternative nontesting approaches such as quantitative structure–activity relationships (QSARs) is encouraged. However, robust QSARs predicting chronic ecotoxicity of organic compounds to fish are not available. The Ecological Structure Activity Relationships (ECOSAR) Class Program is a computerized predictive system that estimates the acute and chronic toxicity of organic compounds for several chemical classes based on their log octanol–water partition coefficient (KOW). For those chemical classes for which chronic training data sets are lacking, acute to chronic ratios are used to predict chronic toxicity to aquatic organisms. Although ECOSAR reaches a high score against the Organisation for Economic Co-operation and Development (OECD) principles for QSAR validation, the chronic QSARs in ECOSAR are not fully compliant with OECD criteria in the framework of REACH or CLP (classification, labeling, and packaging) regulation. The objective of the present study was to develop a chronic ecotoxicity QSAR for fish for compounds acting via nonpolar and polar narcosis. These QSARs were built using a database of quality screened toxicity values, considering only chronic exposure durations and relevant end points. After statistical multivariate diagnostic analysis, literature-based, mechanistically relevant descriptors were selected to develop a multivariate regression model. Finally, these QSARs were tested for their acceptance for regulatory purposes and were found to be compliant with the OECD principles for the validation of a QSAR. Environ Toxicol Chem 2013;32:2217–2225. © 2013 SETAC
Intratumoral vessel density as prognostic factors in head and neck squamous cell carcinoma: A meta‐analysis of literature
Authors: Yu Min , Liu Lei , Liang Chunshui , Li Ping , Ma Xuelei , Zhang Qiongwen , Wei Yuquan 
Published: June 2013

BackgroundThe purpose of this study was to comprehensively and quantitatively summarize the prognostic value of microvessel density (MVD) and lymphatic vessel density (LVD) for the survival of patients with head and neck squamous cell carcinoma (HNSCC).MethodsRelevant literatures were identified using Medline and EMBASE. A meta‐analysis was performed to clarify the prognostic role of MVD and LVD.ResultsA total of 18 articles (13 for MVD and 5 for LVD; n = 1279 and n = 408) were pooled for the global meta‐analysis. The mortality was 1.23‐fold higher for patients whose MVD counts were above the cutoff (risk ratio [RR], 1.23; 95% confidence interval [CI], 0.99–1.52), compared with those below it, and this result was on a borderline (p = .06). The mortality of patients with high LVD counts was 2.07‐fold higher (RR, 2.07; 95% CI, 1.16–3.71; p = .01).ConclusionHigh counts of LVD, not MVD, are associated with worse 5‐year overall survival (OS) in patients with HNSCC. © 2013 Wiley Periodicals, Inc. Head Neck 36: 596–602, 2014
Swallowing in the first year after chemoradiotherapy for head and neck cancer: Clinician‐and patient‐reported outcomes
Authors: Patterson Joanne M. , McColl Elaine , Carding Paul N. , Hildreth Anthony J. , Kelly Charles , Wilson Janet A. 
Published: June 2013

BackgroundThis prospective study evaluated swallowing outcomes prechemoradiotherapy (pre‐CRT) up to 1 year post‐CRT, in a substantial cohort of patients with head and neck cancer and explored factors predicting outcome.MethodsOne hundred twelve patients were assessed pretreatment and at 3, 6, and 12 months posttreatment using a questionnaire, endoscopic assessment, water swallow test, and diet score.ResultsSeventy‐one patients were retained, the majority had oropharyngeal (53%) or hypopharyngeal cancer (20%). A marked deterioration occurred between pretreatment and 3 months posttreatment (p ≤ .01). Significant improvement between 3 and 12 months was found on 2 swallowing measures, but not self reported. Three of the 4 pretreatment assessments predicted outcomes at 1 year.ConclusionCRT results in a marked deterioration on different paradigms of swallowing measurements. Improvement occurs on some clinical measures, but limited change is observed in patients' perceptions. Pretreatment measures are important indicators of long‐term dysphagia. Swallowing recovery is complex, taking different courses between clinical tests and perspectives. © 2013 Wiley Periodicals, Inc. Head Neck 36: 352–358, 2014
Treatment outcomes and feasibility of partial neck irradiation for patients with nasopharyngeal carcinoma with only retropharyngeal lymph node metastasis after intensity‐modulated radiotherapy
Authors: Chen Mo , Tang Ling‐Long , Sun Ying , Mao Yan‐Ping , Li Wen‐Fei , Guo Rui , Liu Li‐Zhi , Li Li , Lin Ai‐Hua , Ma Jun 
Published: June 2013

BackgroundThe purpose of this study was to summarize the treatment outcomes and evaluate the feasibility of partial neck irradiation in patients with nasopharyngeal carcinoma (NPC) with only retropharyngeal lymph nodes (RLNs) metastasis.MethodsBetween January 2003 and December 2007, 54 patients with NPC who received partial neck irradiation to levels II, III, and VA and 100 patients who received whole neck irradiation were reviewed.ResultsThe 5‐year disease free survival (DFS), disease metastasis‐free survival, (DMFS) local relapse‐free survival (LRFS), and regional relapse‐free survival (RRFS) rates were 81.8%, 87.7%, 94.8%, and 98.1%, respectively. The 5‐year RRFS and DFS rates for the partial neck irradiation group and whole neck irradiation group were 98.1% versus 98.0% (p = .882), 87.0% vs 77.0% (p = .117), respectively. Partial neck irradiation was not considered a significant prognostic factor for any endpoint in univariate and multivariate analyses.ConclusionPartial irradiation of neck levels II, III, and VA might be acceptable for patients with NPC with only RLN metastasis. © 2013 Wiley Periodicals, Inc. Head Neck 36: 468–473, 2014
Parotid metastatic disease from cutaneous squamous cell carcinoma: Prognostic role of facial nerve sacrifice, lateral temporal bone resection, immune status and P‐stage
Authors: Shao Angus , Wong Danny K. C. , McIvor Nicholas P. , Mylnarek Alex M. , Chaplin John M. , Izzard Mark E. , Patel Rajan S. , Morton Randall P. 
Published: June 2013

BackgroundRecognized prognostic indicators for metastatic cutaneous squamous cell carcinoma (SCC) of the head and neck include facial nerve involvement, immune status, and “parotid” staging system (P‐stage). We sought to examine the impact of lateral temporal bone resection (LTBR) on prognosis.MethodsWe conducted a retrospective analysis of 160 patients with metastatic cutaneous SCC to the parotid. All patients had parotidectomy and neck dissection; 27% had additional LTBR when the tumor was adherent to the temporal bone.ResultsOverall 5‐year survival was 48%, disease‐specific survival 77%, and locoregional control 83%. Corresponding results for immunocompetent versus immunocompromised were 55%, 86%, and 87% versus 12%, 48%, and 64%. On Cox regression analysis, only immunocompromised status (ie, lymphoproliferative disorder, organ‐transplant patient) was prognostically significant (p < .001).ConclusionMore radical resection that may include LTBR mitigates the poorer prognosis with advanced disease in our series. Treatment must be individualized in immunocompromised patients who have shortened overall survival. © 2013 Wiley Periodicals, Inc. Head Neck 36: 545–550, 2014
Optimization of long‐term outcomes for patients with esthesioneuroblastoma
Authors: Ow Thomas J. , Hanna Ehab Y. , Roberts Dianna B. , Levine Nicholas B. , El‐Naggar Adel K. , Rosenthal David I. , DeMonte Franco , Kupferman Michael E. 
Published: June 2013

BackgroundEsthesioneuroblastoma is a rare cancer of the anterior cranial base that arises in the region of the olfactory rootlets. The purpose of this study was to review the long‐term outcomes of patients diagnosed with esthesioneuroblastoma (ENB) treated at a single institution to determine factors associated with improved disease control and survival.MethodsA retrospective review of 70 patients with ENB treated at the University of Texas MD Anderson Cancer Center between 1992 and 2007 was undertaken. Survival and recurrence was analyzed and compared using the Kaplan–Meier method and log‐rank statistics.ResultsSeventy patients were reviewed. The majority (77%) had T3 or T4 disease at presentation, 38% identified as modified Kadish stage C or D. Ninety percent of patients received surgical resection as part of their treatment, and 66% received postoperative radiation or chemoradiation. The median follow‐up was 91.4 months (7.6 years). Forty‐eight percent of patients developed recurrent disease and the median time to recurrence was 6.9 years. Overall and disease‐specific median survival was 10.5 and 11.6 years, respectively. Patients who were treated with surgery alone had a median disease‐specific survival of 87.9 months, whereas those who were treated with surgery and postoperative radiation had a median disease‐specific survival of 218.5 months (p = .047).ConclusionPatients with ENB can achieve favorable long‐term survival, even if disease is locally advanced. Survival is improved considerably when surgical resection is followed by postoperative radiation. However, recurrence rates and mortality remain high, and therefore long‐term observation in these patients is warranted. © 2013 Wiley Periodicals, Inc. Head Neck 36: 524–530, 2014
Analysis of the interannual variability of annual daily extreme water levels in the St Lawrence River and Lake Ontario from 1918 to 2010
Authors: Assani Ali A. , Landry Raphaëlle , Biron Stacey , Frenette Jean‐Jacques 
Published: June 2013

AbstractWe compared the interannual variability of annual daily maximum and minimum extreme water levels in Lake Ontario and the St Lawrence River (Sorel station) from 1918 to 2010, using several statistical tests. The interannual variability of annual daily maximum extreme water levels in Lake Ontario is characterized by a positive long‐term trend showing two shifts in mean (1929–1930 and 1942–1943) and a single shift in variance (in 1958–1959). In contrast, for the St Lawrence River, this interannual variability is characterized by a negative long‐term trend with a single shift in mean, which occurred in 1955–1956. As for annual daily minimum extreme water levels, their interannual variability shows no significant long‐term change in trend. However, for Lake Ontario, the interannual variability of these water levels shows two shifts in mean, which are synchronous with those for maximum water levels, and a single shift in variance, which occurred in 1965–1966. These changes in trend and stationarity (mean and variance) are thought to be due to factors both climatic (the Great Drought of the 1930s) and human (digging of the Seaway and construction of several dams and locks during the 1950s). Despite this change in means and variance, the four series are clearly described by the generalized extreme value distribution. Finally, annual daily maximum and minimum extreme water levels in the St Lawrence and Lake Ontario are negatively correlated with Atlantic multidecadal oscillation over the period from 1918 to 2010. Copyright © 2013 John Wiley & Sons, Ltd.