bluuebunny/crossref_metadata_2025_split huggingface dataset:
Competence assessment of senior vascular trainees using a carotid endarterectomy bench model
Authors: Black S A , Harrison R H , Horrocks E J , Pandey V A , Wolfe J H N 
Published: June 2007

Abstract

Background
Competency-based assessment is being introduced to surgical training. The value of bench-top technical skills assessment using a synthetic carotid endarterectomy (CEA) model was evaluated in vascular trainees and consultants.

Methods
Forty-one surgeons (13 junior trainees, 15 senior trainees and 13 experienced consultants with experience of more than 50 CEAs) performed a three-throw knot-tying exercise on a jig and a CEA on the bench model. A composite score for knot-tying was calculated, incorporating electromagnetic motion analysis. CEA technical skill was assessed using validated rating scales by blinded video analysis.

Results
Senior trainees performed better than junior trainees in knot-tying (P = 0·025) as well as generic (P &lt; 0·001) and procedural (P &lt; 0·001) skills on CEA model assessment. There was no difference between senior trainees and consultants on any of these measures. The CEA model interobserver reliability was high for all rating scales (generic α = 0·974, procedural α = 0·952, end-product α = 0·976).

Conclusion
Senior trainees achieved the same score as consultants, suggesting a similar level of basic technical skill and knowledge required to perform CEA, and were significantly better than junior trainees. Performance on the bench model could provide an early assessment for suitability to proceed to operative training in a competency-based training and assessment programme.
Chemoenzymatic Synthesis of Prenylated Indole Derivatives by Using a 4‐Dimethylallyltryptophan Synthase from Aspergillus fumigatus
Authors: Steffan Nicola , Unsöld Inge A. , Li Shu‐Ming 
Published: June 2007

AbstractA 4‐dimethylallyltryptophan synthase, FgaPT2, has been identified in the genome of Aspergillus fumigatus. In a previous study, FgaPT2 was overexpressed in Saccharomyces cerevisiae and characterized biochemically. A higher protein yield (up to 100‐fold higher than that for S. cerevisiae) has now been achieved by overexpression in E. coli; this has permitted investigation into substrate specificity with alternative substances. FgaPT2 accepted 17 of 37 commercially available indole derivatives as substrates. Tryptophan derivatives that carry methyl groups at the indole ring showed a different acceptance from those with methyl groups on the side chain. 5‐Hydroxytryptophan was well accepted by FgaPT2, while the halogenated derivatives were not accepted. Decarboxylation, deamination, or oxidative deamination of tryptophan, as well as replacement of the NH2 group by OH, or of the COOH group by CH2COOH or CONHOH resulted in decreased but still significant enzymatic activity. None of the tested tryptophan‐containing dipeptides was accepted by FgaPT2. Structural elucidation of isolated enzymatic products by NMR and MS analyses proved unequivocally that the prenylation was regioselective at position C4 of the indole ring in the presence of dimethylallyl diphosphate. Determination of the kinetic parameters revealed that L‐tryptophan was accepted as the best substrate by the enzyme, followed by 5‐,6‐,7‐methyltryptophan and L‐abrine. The enzymatic rate constant (kcat Km−1) of nine selected substrates were found to be about 1.0 to 6.5 % of that for L‐tryptophan. Overnight incubation with eight substances showed that the conversion ratio to their prenylated derivatives was in the range 32.5 to 99.7 %. This provides evidence that 4‐dimethylallylated indole derivatives can be produced by chemoenzymatic synthesis with FgaPT2.
Redox Chemistry of Copper–Amyloid‐β: The Generation of Hydroxyl Radical in the Presence of Ascorbate is Linked to Redox‐Potentials and Aggregation State
Authors: Guilloreau Luc , Combalbert Sarah , Sournia‐Saquet Alix , Mazarguil Honoré , Faller Peter 
Published: June 2007

AbstractAggregation of the β‐amyloid peptide (Aβ) to amyloid plaques is a key event in Alzheimer's disease. According to the amyloid‐cascade hypothesis, Aβ aggregates are toxic to neurons through the production of reactive oxygen species (ROS). Copper ions play an important role, because they are able to bind to Aβ and influence its aggregation properties. Moreover, Cu–Aβ is supposed to be directly involved in ROS production. To get a better understanding of these reactions, we measured the production of HO. and the redox potential of Cu–Aβ. The results were compared to other biological copper–peptide complexes in order to get an insight into the biological relevance. Cu–Aβ produced more HO. than the complex of copper with Asp‐Ala‐His‐Lys (Cu–DAHK), but less than with Gly‐His‐Lys (Cu–GHK). Cyclic voltammetry revealed that the order for reduction potential is Cu–GHK>Cu–Aβ>Cu–DAHK, but for the oxidation potential the order is reversed. Thus, easier copper redox cycling correlated to higher HO. production. The copper complex of the form Aβ1–42 showed a HO. production five‐times higher than that of the form Aβ1–40. Time‐dependence and aggregation studies suggest that an aggregation intermediate is responsible for this increased HO. production.
Percutaneous coronary intervention for chronic total occlusions: Improved survival for patients with successful revascularization compared to a failed procedure
Authors: Aziz Shahid , Stables Rodney H. , Grayson Antony D. , Perry Raphael A. , Ramsdale David R. 
Published: June 2007

AbstractBackground:There are limited data on the impact of successful chronic total occlusion (CTO) revascularization by percutaneous coronary intervention (PCI) on survival. We performed a retrospective study comparing the survival between patients with a successful and a failed CTO revascularization by PCI.Methods:Between January 1, 2000 and June 30, 2004, 543 of 5803 (9.4%) patients underwent PCI for a CTO at our center. A CTO was defined as an occlusion of the artery present for at least 3 months with Thrombolysis in Myocardial Infarction flow grade 0 or 1. Patient records were linked to a national database to monitor all deaths during follow up. Propensity matching was used to balance out case mix differences.Results:Technical success for CTO was 377 of 543 (69.4%). In‐hospital mortality was 0.3% and 1.2% for the CTO success and CTO failure patients, respectively. During a mean (SD) follow up of 1.7 (0.5) years, the mortality rate was 2.5% in the CTO success patients and 7.3% in the CTO failure patients. The crude hazard ratio for death with CTO failure was 3.92 (95% confidence intervals 1.56–10.07; P = 0.004). The rates of coronary artery bypass were 3.2% vs. 21.7% (P < 0.001) for the CTO success and CTO failure patients, respectively. Our propensity matched 157 CTO success to CTO failure patients and the associated hazard ratio for death with CTO failure was 4.63 (95% confidence interval 1.01–12.61; P = 0.049). Multivariate analysis showed that CTO failure was an independent predictor of death.Conclusion:Patients with a successful revascularization of a CTO by PCI have an increased survival rate compared to patients with a failed CTO procedure. © 2007 Wiley‐Liss, Inc.
Managing patient dose in interventional cardiology
Authors: Balter Stephen , Moses Jeffrey 
Published: June 2007

AbstractThis paper introduces a methodology for managing the radiation delivered to individual patients, incidental to their fluoroscopically guided interventional procedures. Because rare, but devastating skin injuries have occurred, radiation should be monitored and managed as well as drugs or radiographic contrast media. Dose metrics such as the total dose delivered to a reference point (reference point dose) should be used for this purpose. Fluoroscopy time is a poor independent predictor of skin dose in an individual patient. The concept of a “significant dose” is introduced. This is a predetermined action level of the selected dose metric. The numerical value is set based on classes of patient and procedural factors. Exceeding this value triggers processes for clinical justification of radiation usage and patient follow‐up. Slightly exceeding the significant dose threshold during a procedure should be highly unlikely to cause skin injury. © 2007 Wiley‐Liss, Inc.
Diboryl and Diboranyl Porphyrin Complexes: Synthesis, Structural Motifs, and Redox Chemistry: Diborenyl Porphyrin or Diboranyl Isophlorin?
Authors: Weiss Andre , Hodgson Michael C. , Boyd Peter D. W. , Siebert Walter , Brothers Penelope J. 
Published: June 2007

AbstractThe syntheses of diboryl porphyrin complexes [(BX2)2(ttp)] (ttp: dianion of tetra‐p‐tolylporphyrin) and the BB single‐bond diboranyl complexes [(BX)2(ttp)] (X=F, Cl, Br, I) are given. The former are prepared from the reactions of BX3 (X=F, Cl) with [Li2(ttp)] and the latter from B2Cl4 (X=Cl), the reaction of SbF3 with [(BCl)2(ttp)] (for X=F), and, in the cases of X=Br or I, in a remarkable reductive coupling reaction resulting directly from the reaction of BBr3 or BI3 with [Li2(ttp)]. Density functional theory (DFT) calculations on the thermochemical parameters for the reductive coupling reactions (and those calculated for related dipyrromethene complexes) indicate that a combination of the reducing ability of bromide and iodide ions combined with the constrained environment of the porphyrin ligand contribute to the driving force. The reductive coupling is also observed in the reaction of [(BCl2)2(ttp)] with nBuLi to give [(BnBu)2(ttp)], which was characterised crystallographically. The reaction of [(BCl)2(ttp)] with catechol gives a boron catecholato porphyrin complex, [B2(O2C6H4)(ttp)]. Chloride abstraction from [(BCl)2(ttp)] gives the planar dication [B2(ttp)]2+, whereas chemical reduction of [(BCl)2(ttp)] by using magnesium anthracenide gives a neutral complex, [B2(ttp)], in which the TTP ligand has been reduced by two electrons to give an unusual example of an isophlorin complex. The cationic and neutral complexes [B2(ttp)]2+ and [B2(ttp)] were characterised through a combination of spectroscopic data that is supported by DFT calculations on the porphine analogues.
Fully Fluorinated Imidodiphosphinate Shells for Visible‐ and NIR‐Emitting Lanthanides: Hitherto Unexpected Effects of Sensitizer Fluorination on Lanthanide Emission Properties
Authors: Glover Peter B. , Bassett Andrew P. , Nockemann Peter , Kariuki Benson M. , Van Deun Rik , Pikramenou Zoe 
Published: June 2007

AbstractIn this paper we demonstrate that the effect of aromatic CF substitution in ligands does not always abide by conventional wisdom for ligand design to enhance sensitisation for visible lanthanide emission, in contrast with NIR emission for which the same effect coupled with shell formation leads to unprecedented long luminescence lifetimes. We have chosen an imidodiphosphinate ligand, N‐{P,P‐di(pentafluorophinoyl)}‐P,P‐dipentafluorophenylphosphinimidic acid (HF20tpip), to form ideal fluorinated shells about all visible‐ and NIR‐emitting lanthanides. The shell, formed by three ligands, comprises twelve fully fluorinated aryl sensitiser groups, yet no‐high energy XH vibrations that quench lanthanide emission. The synthesis, full characterisation including X‐ray and NMR analysis as well as the photophysical properties of the emissive complexes [Ln(F20tpip)3], in which Ln=Nd, Sm, Eu, Gd, Tb, Dy, Er, Yb, Y, Gd, are reported. The photophysical results contrast previous studies, in which fluorination of alkyl chains tends to lead to more emissive lanthanide complexes for both visible and NIR emission. Analysis of the fluorescence properties of the HF20tpip and [Gd(F20tpip)3] reveals that there is a low‐lying state at around 715 nm that is responsible for partially quenching of the signal of the visible emitting lanthanides and we attribute it to a π–σ* state. However, all visible emitting lanthanides have long lifetimes and unexpectedly the [Dy(F20tpip)3] complex shows a lifetime of 0.3 ms, indicating that the elimination of high‐energy vibrations from the ligand framework is particularly favourable for Dy. The NIR emitting lanthanides show strong emission signals in powder and solution with unprecedented lifetimes. The luminescence lifetimes of [Nd(F20tpip)3], [Er(F20tpip)3] and [Yb(F20tpip)3] in deuteurated acetonitrile are 44, 741 and 1111 μs. The highest value observed for the [Yb(F20tpip)3] complex is more than half the value of the Yb ion radiative lifetime.
Aromaticity: Molecular‐Orbital Picture of an Intuitive Concept
Authors: Pierrefixe Simon C. A. H. , Bickelhaupt F. Matthias 
Published: June 2007

AbstractGeometry is one of the primary and most direct indicators of aromaticity and antiaromaticity: a regular structure with delocalized double bonds (e.g., benzene) is symptomatic of aromaticity, whereas a distorted geometry with localized double bonds (e.g., 1,3‐cyclobutadiene) is characteristic of antiaromaticity. Here, we present a molecular‐orbital (MO) model of aromaticity that explains, in terms of simple orbital‐overlap arguments, why this is so. Our MO model is based on accurate Kohn–Sham DFT analyses of the bonding in benzene, 1,3‐cyclobutadiene, cyclohexane, and cyclobutane, and how the bonding mechanism is affected if these molecules undergo geometrical deformations between regular, delocalized ring structures, and distorted ones with localized double bonds. We show that the propensity of the π electrons is always, that is, in both the aromatic and antiaromatic molecules, to localize the double bonds, against the delocalizing force of the σ electrons. More importantly, we show that the π electrons nevertheless decide about the localization or delocalization of the double bonds. A key component of our model for uncovering and resolving this seemingly contradictory situation is to analyze the bonding in the various model systems in terms of two interpenetrating fragments that preserve, in good approximation, their geometry along the localization/delocalization modes.
One‐Step Synthesis of Highly Water‐Soluble Magnetite Colloidal Nanocrystals
Authors: Ge Jianping , Hu Yongxing , Biasini Maurizio , Dong Chungli , Guo Jinghua , Beyermann Ward P. , Yin Yadong 
Published: June 2007

AbstractA high‐temperature solution‐phase hydrolysis approach has been developed for the synthesis of colloidal magnetite nanocrystals with well‐controlled size and size distribution, high crystallinity, and high water solubility. The synthesis was accomplished by the hydrolysis and reduction of iron(III) cations in diethylene glycol with a rapidly injected solution of sodium hydroxide at an elevated temperature. The high reaction temperature allows for control over size and size distribution and yields highly crystalline products. The superior water solubility is achieved by using a polyelectrolyte, that is, poly(acrylic acid) as the capping agent, the carboxylate groups of which partially bind to the nanocrystal surface and partially extend into the surrounding water. The direct synthesis of water‐soluble nanocrystals eliminates the need for additional surface modification steps which are usually required for treating hydrophobic nanocrystals produced in nonpolar solvents through the widely recognized pyrolysis route. The abundant carboxylate groups on the nanocrystal surface allow further modifications, such as bioconjugation, as demonstrated by linking cysteamine to the particle surface. The monodisperse, highly water‐soluble, superparamagnetic, and biocompatible magnetite nanocrystals should find immediate important biomedical applications.
Characterisation of a Novel Growth Hormone Variant Comprising a Thioether Link between Cys182 and Cys189
Authors: Datola Antonio , Richert Sophie , Bierau Horst , Agugiaro David , Izzo Anna , Rossi Mara , Cregut David , Diemer Hélène , Schaeffer Christine , Van Dorsselaer Alain , Giartosio Carlo Emanuele , Jone Carl 
Published: June 2007

AbstractA novel variant of recombinant human growth hormone (r‐hGH), isolated from biopharmaceutical preparations produced in E. coli, was identified and characterised. This variant contains a nonreducible thioether bridge near the C terminus between Cys182 and Cys189 and was characterised using various analytical techniques. As previous work by Cunningham and Wells (1993) highlighted the involvement of several residues in this part of the sequence in the binding and affinity of the molecule to its receptor, the presence of this modified intramolecular link may have important implications with regard to the biological behaviour of the molecule. Furthermore, as the conversion of a disulfide into a thioether was previously reported for a therapeutic monoclonal antibody (Tous et al., 2005), this may imply that disulfide bridges located in this part of the molecule have a generic susceptibility to thioether formation. This in turn is relevant to the biopharmaceutical industry for monitoring the integrity of disulfide bridges near the protein C terminus. The present study exhibits a state of the art physicochemical investigation for the unequivocal elucidation of a novel structure involving peptide mapping with mass spectrometry and de novo peptide sequencing. Changes in the higher order structure of the molecule were highlighted by near UV circular dichroism and molecular modelling.
Validation of the 6thedition AJCC pancreatic cancer staging system
Authors: Bilimoria Karl Y. , Bentrem David J. , Ko Clifford Y. , Ritchey Jamie , Stewart Andrew K. , Winchester David P. , Talamonti Mark S. 
Published: June 2007

AbstractBACKGROUNDWith the development of stage‐specific treatments for pancreatic cancer, controversies exist concerning optimal clinical and pathologic staging. The most recent edition of the American Joint Committee on Cancer (AJCC) Cancer Staging Manual 6thEdition included some notable modifications. In anticipation of the 7thedition's publication, the authors evaluated the predictive ability of the current pancreatic adenocarcinoma staging system.METHODSBy using the National Cancer Data Base (1992–1998), 121,713 patients were identified with pancreatic adenocarcinoma. All patients were restaged by AJCC 6thedition guidelines. Stage‐specific overall survival was estimated by using the Kaplan‐Meier method and compared with log‐rank tests. Concordance indices were calculated to evaluate the discriminatory power of the staging system. Cox modeling was used to determine the relative impact of T, N, and M classification on survival.RESULTSFor all patients, there was 5‐year survival discrimination by stage (P< .0001). For patients who underwent pancreatectomy, stage predicted 5‐year survival: stage IA, 31.4%; IB, 27.2%; IIA, 15.7%; IIB, 7.7%; III, 6.8%; IV, 2.8% (P< .0001). The concordance index for the staging system was 0.631 for all patients, 0.613 for those who underwent pancreatectomy, and 0.596 for patients who did not undergo resection. In patients who underwent pancreatectomy, tumor size, nodal status, and distant metastases were independent predictors of survival (P< .0001).CONCLUSIONSThis is the first large‐scale validation of the pancreatic cancer staging system. AJCC 6thedition staging guidelines are accurate with respect to survival. Further investigation is needed to integrate new molecular and biochemical markers into the staging scheme. Cancer 2007; 110:738–44. © 2007 American Cancer Society.
Enabling service adaptability with versatile anycast
Authors: Szymaniak Michal , Pierre Guillaume , Simons‐Nikolova Mariana , van Steen Maarten 
Published: June 2007

AbstractWe present versatile anycast, which allows a service running on a varying collection of nodes scattered over a wide‐area network to present itself to the clients as one running on a single node. Providing a single logical address enables the client‐side software to preserve the traditional service access model based on single access points. At the same time, the dynamic composition of anycast groups implemented by versatile anycast enables the server‐side service infrastructure to evolve and adapt to changing network conditions. We implement versatile anycast using Mobile IPv6, which decouples the logical addresses of mobile nodes from their physical location. We exploit that decoupling to implement logical
service addresses that are not bound to any physical nodes, and employ standard MIPv6 mechanisms to dynamically map each such address onto individual service nodes. Our solution enables a service to transparently hand off clients among the service nodes at the network level while preserving optimal routing between the clients and the service nodes. We demonstrate that the overhead of versatile anycasting is very low. In particular, the client‐perceived handoff time is shown to be a linear function of the latencies among the client and the service nodes participating in the handoff. Copyright © 2007 John Wiley & Sons, Ltd.
Role of direct immunofluorescence on Tzanck smears in pemphigus vulgaris
Authors: Aithal Vijay , Kini Usha , Jayaseelan Elizabeth 
Published: June 2007

AbstractThe Tzanck smear is a simple, sensitive, and rapid test to diagnose pemphigus vulgaris (PV), a life threatening autoimmune blistering disorder. The presence of acantholytic cells in cytology is indicative of but not specific for PV. Hence, a direct Immunofluorescence (DIF) test to demonstrate immunoglobulin deposits on the acantholytic cells would make the Tzanck test more specific, in addition to being a rapid test. Twenty untreated patients with PV confirmed histopathologically were enrolled to evaluate the efficacy of using DIF technique using IgG on Tzanck smear samples. The DIF smears were compared with DIF on skin biopsies in the same patient. This prospective pilot study approved by the institutional ethics committee was carried out in a tertiary health care hospital in a developing country. Of the 15 patients presenting within 3 mo of onset of the illness, 40% (n = 6) showed DIF positivity on Tzanck smear, when compared with 46.67% (n = 7) on skin biopsy. On the other hand, of the five patients presenting beyond 3 mo of their illness, only 20% (n = 2) showed positivity on Tzanck, when compared with all 100% (n = 5) on skin biopsy. The study, thus, suggests that DIF on skin biopsy is comparable to biopsy in diagnosing early PV. This preliminary study proposes that the use of DIF on Tzanck smear is a simple, rapid, painless, and user‐friendly out‐patient procedure for the diagnosis of early PV, even for relatively inaccessible lesions in the oral cavity and flexural regions. This methodology would be of great help in outlying and rural facilities lacking proper histological equipment, thus avoiding the need for a surgical or punch biopsy or heavy investment in laboratory equipment and expertise. Probable reasons for DIF negativity on Tzanck smears are also discussed. Diagn. Cytopathol. 2007;35:403–407. © 2007 Wiley‐Liss, Inc.
Primary pure squamous cell carcinoma of the breast diagnosed by fine‐needle aspiration cytology: A case study using liquid‐based cytology
Authors: Vera‐Alvarez J. , García‐Prats M. D. , Marigil‐Gómez M. , Abascal‐Agorreta M. , López‐López J. I. , Ramón‐Cajal J. M. 
Published: June 2007

AbstractPure primary squamous cell carcinoma (SCC) is an extremely rare type of breast tumor. We report one of such cases in a 32‐year‐old woman, diagnosed by fine‐needle aspiration cytology (FNAC). Aspiration smears were characterized by squamous cells, both isolated and in aggregates, at various stages of maturation. The tumor was excised, and the histologic sections confirmed the cytologic diagnosis. Pure primary SCC of the breast has a distinctive cytomorphologic appearance, and diagnosis of this tumor by FNAC is possible. For its diagnosis, the exclusion of SCC of local cutaneous structures and metastasis of distant squamous carcinoma are mandatory. Diagn. Cytopathol. 2007;35:429–432. © 2007 Wiley‐Liss, Inc.