bluuebunny/crossref_metadata_2025_split huggingface dataset:
A new assessment methodology for virtual reality surgical simulators
Authors: Bayona Sof ía , Fernández‐Arroyo José Manuel , Bayona Pilar , Pastor Luis 
Published: January 2009

AbstractThis paper presents an assessment methodology to validate surgical simulators which will help researchers in avoiding most common errors by providing a complete structured guide. The methodology organizes the questions depending on the validities they are related to, helping in objectives' definition and consistent hypothesis formulation. We will define the study depending on its purpose, time course and the study factor assignment, taking into account legal and ethical issues and choosing the population and sample size. If it is an experimental study, we will determine if there exist a control group and the operational definition of variables. We will avoid extraneous variables and make our study blind, establishing the final evaluation procedure, and stipulating actuation and observation protocols. A feasibility study will be performed before executing the pilot and final studies in which we will analyse the data as indicated by the statistical plan, obtaining our results and conclusions. We provide an example, applying the assessment methodology step by step to the evaluation of a virtual reality arthroscopy simulator with haptic feedback. Finally, possible experiments are proposed as well as a conscientious study of different alternatives for the final evaluation procedure, and an extended proposal of surgical competence assessment measures. Copyright © 2009 John Wiley & Sons, Ltd.
Spatial camera orientation control by rotation‐minimizing directed frames
Authors: Farouki Rida T. , Giannelli Carlotta 
Published: January 2009

AbstractThe use of rotation‐minimizing directed frames (RMDFs) for defining smoothly varying camera orientations along given spatial paths, in real or virtual environments, is proposed. A directed frame on a space curve${\bf r}(\xi)$is a varying orthonormal basis$({\bf o},{\bf p},{\bf q})$for ℝ3such that${\bf o}(\xi)={\bf r}(\xi)/|{\bf r}(\xi)|$coincides with the unit polar vector from the origin to each curve point, and such a frame is rotation‐minimizing if its angular velocity vector${\bf \omega}$maintains a vanishing component alongo. To facilitate computation of rotation‐minimizing directed frames, it is shown that the basic theory is equivalent to the established theory for rotation‐minimizing adapted frames—for which one frame vector coincides with the tangent${\bf t}(\xi)={\bf r}'(\xi)/|{\bf r}'(\xi)|$at each curve point—if one replaces the given space curve by its anti‐hodograph (i.e., indefinite integral). A family of polynomial curves on which RMDFs can be computed exactly by a rational function integration, the Pythagorean (P) curves, is also introduced, together with algorithms for their construction. Copyright © 2009 John Wiley & Sons, Ltd.
Formylglycine Aldehyde Tag—Protein Engineering through a Novel Post‐translational Modification
Authors: Frese Marc‐André , Dierks Thomas 
Published: January 2009

AbstractOxidation of a specific cysteine residue to Cα‐formylglycine is a novel post‐translational modification that is directed by a short recognition motif commonly found in pro‐ and eukaryotic sulfatases. As recently shown by C. Bertozzi and co‐workers, this system can be employed in protein engineering to equip proteins with genetically encoded aldehyde tags for site‐specific labeling, conjugation and immobilization.magnified image
Electronic Structure and Absorption Spectra of Biferrocenyl and Bisfulvalenide Diiron Radical Cations: Detection and Assignment of New Low‐Energy Transitions
Authors: Warratz Ralf , Aboulfadl Hanane , Bally Thomas , Tuczek Felix 
Published: January 2009

AbstractNew transitions: Low‐energy electronic transitions have been detected spectroscopically in the FeII–FeIII mixed‐valent biferrocenyl radical cation, but are absent in the spectra of the neutral analogue. They have been assigned by time‐dependent DFT calculations (squares in figure). Analogous investigations were performed for the bisfulvalenide FeII–FeIII radical cation.magnified imageUV‐visible/near‐IR (NIR)/mid‐IR (MIR) solution, solid‐state, and matrix‐isolation electronic absorption spectra of the FeII–FeIII mixed‐valent homobimetallic compounds biferrocenyl triiodide (1) and 1′,1′′′‐diethylbiferrocenyltriiodide (2) reveal the presence of a low‐energy transition in the MIR region that has not been reported before. The new absorption feature and the known NIR band are both assigned to intervalence charge‐transfer (IVCT) transitions. To obtain insight into the electronic structures of 1 and 2, DFT calculations with the BP86 functionals and different basis sets have been performed. Based on the molecular orbital scheme of cation 1, one band corresponds to the transition between the highest occupied d orbitals on the two iron centers, whereas the other one is assigned to a transition from a lower‐lying d orbital to the d orbital. For comparison, the doubly bridged bisfulvalenide diiron cation (3) has been investigated by optical absorption spectroscopy and DFT calculations. The experimental and theoretical results are discussed with respect to the degree of electron localization/delocalization in these systems.
Metal‐Dependent Reaction Tuning with Cyclopentylmetal Reagents: Application to the Asymmetric Synthesis of (+)‐α‐Conhydrine and (S)‐2‐Cyclopentyl‐2‐phenylglycolic Acid
Authors: Roy Siddharth , Sharma Anubha , Mula Soumyaditya , Chattopadhyay Subrata 
Published: January 2009

AbstractTuning in: The reaction of halocyclopentane organometallic reagents can be tuned by the choice of metal (see scheme). Cyclopentylmagnesium bromide reduces aldehydes and ketones to the corresponding alcohols. However, in the presence of ZnCl2, normal Grignard addition to the ketones gives tertiary alcohols with complete diastereoselectivity. These protocols were used in the asymmetric synthesis of two medicinally important compounds.magnified imageThe reaction profile of the cyclopentyl organometallic reagents with the aliphatic ketones can be tuned to reduction or addition by changing the metal atom. Cyclopentylmagnesium bromide (CPMB) reduces aromatic and aliphatic aldehydes and ketones to the corresponding alcohols without any CC bond formation and shows good diastereoselectivity in the reduction of the substituted cyclic and polycyclic ketones as well as chiral α‐oxygenated aliphatic ketones. However, in the presence of 10 mol % of ZnCl2, the cyclopentylmagnesium halides follow a normal Grignard addition to the ketones to give tertiary alcohols with complete diastereoselectivity. The reductive as well as the addition protocols were used for the asymmetric synthesis of two medicinally important compounds, (+)‐α‐conhydrine and (S)‐2‐cyclopentyl‐2‐phenylglycolic acid.
Prospects of Metal Complexes Peripherally Substituted with Sugars in Biomedicinal Applications
Authors: Gottschaldt Michael , Schubert Ulrich S. 
Published: January 2009

AbstractSugar is good for you! The latest developments in the field of sugar substitution of metal complexes and its influence on the action of these complexes in biological systems are discussed (see figure). In particular, the progress in applications as selective tracers and therapeutics in connection to the underlying chemical structure is highlighted.magnified imageMetal complexes possess unique tunable properties, such as radioactivity, cytotoxicity or photophysical features, enabling them to act as diagnostic tracers or therapeutic agents. In applying them in biological systems, it is often necessary to enhance their solubility and biocompatibility. To achieve such goals, like the targeting of binding domains, transport systems and enzyme activities, the attachment of carbohydrate moieties appears to be suitable. Sugar‐substitution in the periphery of metal complexes has therefore become a strongly growing field of research. Outlined herein is a selection of recent examples.
Highly Efficient Visible‐Light Plasmonic Photocatalyst Ag@AgBr
Authors: Wang Peng , Huang Baibiao , Zhang Xiaoyang , Qin Xiaoyan , Jin Hao , Dai Ying , Wang Zeyan , Wei Jiyong , Zhan Jie , Wang Shaoying , Wang Junpeng , Whangbo Myung‐Hwan 
Published: January 2009

AbstractVisible improvements: Owing to the plasmon resonance of silver nanoparticles deposited on the surface of AgBr, the newly‐prepared plasmonic photocatalyst Ag§AgBr has a strong absorption in the visible region (see picture) and shows high efficiency in the photodegradation of organic pollutants under visible light.magnified image
Triclosan Derivatives: Towards Potent Inhibitors of Drug‐Sensitive and Drug‐Resistant Mycobacterium tuberculosis
Authors: Freundlich Joel S. , Wang Feng , Vilchèze Catherine , Gulten Gulcin , Langley Robert , Schiehser Guy A. , Jacobus David P. , Jacobs William R. , Sacchettini James C. 
Published: January 2009

AbstractOvercoming resistance: Isoniazid (INH) is a frontline antitubercular drug that inhibits the enoyl acyl carrier protein reductase InhA. Novel inhibitors of InhA that are not cross‐resistant to INH represent a significant goal in antitubercular chemotherapy. The design, synthesis, and biological activity of a series of triclosan‐based inhibitors is reported, including their promising efficacy against INH‐resistant strains of M. tuberculosis.magnified imageTriclosan has been previously shown to inhibit InhA, an essential enoyl acyl carrier protein reductase involved in mycolic acid biosynthesis, the inhibition of which leads to the lysis of Mycobacterium tuberculosis. Using a structure‐based drug design approach, a series of 5‐substituted triclosan derivatives was developed. Two groups of derivatives with alkyl and aryl substituents, respectively, were identified with dramatically enhanced potency against purified InhA. The most efficacious inhibitor displayed an IC50 value of 21 nM, which was 50‐fold more potent than triclosan. X‐ray crystal structures of InhA in complex with four triclosan derivatives revealed the structural basis for the inhibitory activity. Six selected triclosan derivatives were tested against isoniazid‐sensitive and resistant strains of M. tuberculosis. Among those, the best inhibitor had an MIC value of 4.7 μg mL−1 (13 μM), which represents a tenfold improvement over the bacteriocidal activity of triclosan. A subset of these triclosan analogues was more potent than isoniazid against two isoniazid‐resistant M. tuberculosis strains, demonstrating the significant potential for structure‐based design in the development of next generation antitubercular drugs.
Influence of the baseline 18F‐fluoro‐2‐deoxy‐D‐glucose positron emission tomography results on survival and pathologic response in patients with gastroesophageal cancer undergoing chemoradiation
Authors: Javeri Heta , Xiao Lianchun , Rohren Eric , Komaki Ritsuko , Hofstetter Wayne , Lee Jeffrey H. , Maru Dipen , Bhutani Manoop S. , Swisher Stephen G. , Wang Xuemei , Ajani Jaffer A. 
Published: January 2009

AbstractBACKGROUND:In patients with esophageal cancer who receive chemoradiation, tools to predict/prognosticate outcome before administering therapy are lacking. The authors evaluated initial standardized unit value (iSUV) of 18F‐fluoro‐2‐deoxy‐D‐glucose positron emission tomography and its association with overall survival and the degree of pathologic response after surgery.METHODS:The authors analyzed 161 patients with esophageal adenocarcinoma who had chemoradiation followed by surgery. The log‐rank test, univariate Cox proportional hazards model, Kaplan‐Meier survival plot, and Fisher exact test were used to analyze dichotomized iSUV and its association with overall survival and pathologic response.RESULTS:The median age of 161 patients was 61 years (range, 26‐80 years) and the majority of patients had lower esophageal or gastroesophageal junction involvement. All patients received fluoropyrimidine and, most commonly, a taxane or platinum compound with concomitant radiation. The median radiation dose was 45 grays (Gy) (range, 45 Gy‐50.4 Gy). The median iSUV for all patients was 10.1 (range, 0‐58). Using the Fisher exact test, iSUV was not found to be associated with the location of the primary cancer. iSUV higher than the median (10.1) was associated with a better pathologic response (P= .06). Patients with primary cancer with iSUV >10.1 had a lower risk for death (hazards ratio of 0.56) compared with those with iSUV ≤10.1. Higher iSUV was nonsignificantly associated with improved survival (P= .07).CONCLUSIONS:Data from the current study suggest that lower iSUV is associated with poor survival and lower probability of response to chemoradiation. iSUV needs to be further evaluated because it may be used to complement other imaging or biomarker assessments to individualize therapy. Cancer 2009. © 2009 American Cancer Society.
Phase II trial of neoadjuvant docetaxel and gefitinib followed by radical prostatectomy in patients with high‐risk, locally advanced prostate cancer
Authors: Vuky Jacqueline , Porter Christopher , Isacson Christina , Vaughan Matthew , Kozlowski Paul , Picozzi Vincent , Corman John 
Published: January 2009

AbstractBACKGROUND:Prostate cancer trials investigating neoadjuvant hormonal therapy, followed by surgery, have demonstrated that elimination of all tumor cells from the primary site is rare. The authors report a phase 2 trial assessing the efficacy and toxicity of docetaxel and gefitinib in patients with high‐risk localized prostate cancer as neoadjuvant therapy before radical prostatectomy (RP).METHODS:Thirty‐one patients with high‐risk prostate cancer were treated with docetaxel and gefitinib for 2 months before RP. All patients met the criteria of clinical stage T2b‐3 or serum prostate‐specific antigen (PSA) level >20 ng/mL, or Gleason score of 8 to 10. The primary endpoint was pathologic complete response. Secondary objectives included clinical response. When available, endorectal coil magnetic resonance imaging (eMRI) was performed as part of clinical response evaluation. Immunohistochemical staining of epidermal growth factor receptor and HER‐2/neu was performed on prechemotherapy and postchemotherapy prostate tissue.RESULTS:The median age of the patients was 60 years, the median pretreatment PSA level was 7.43 ng/mL, and the median Gleason score was 8. Clinical staging prior to treatment consisted of: T1 in 4 patients, T2 in 17 patients, and T3 in 10 patients. One patient with enlarged pelvic adenopathy and T4 disease did not undergo RP. Thirty patients received all scheduled therapies including RP. Grade 3 toxicities included asymptomatic liver function test elevation in 4 (13%) patients, diarrhea in 1 (3%) patient, and fatigue in 1 (3%) patient. One patient experienced grade 4 toxicity with elevated alanine aminotransferase. RP specimen pathology demonstrated residual carcinoma in all cases. Twenty‐nine (94%) patients achieved a clinical partial response, including 35% of patients who demonstrated radiographic improvement on eMRI.CONCLUSIONS:No pathologic complete response was noted in 31 patients treated with docetaxel and gefitinib. This combination was well tolerated, and did not result in increased surgical morbidity. Cancer 2009. © 2009 American Cancer Society.
Influence of Ions on Aqueous Acid–Base Reactions
Authors: Cox M. Jocelyn , Siwick Bradley J. , Bakker Huib J. 
Published: January 2009

AbstractWe study the effects of bromide salts on the rate and mechanism of the aqueous proton/deuteron‐transfer reaction between the photoacid 8‐hydroxy‐1,3,6‐pyrenetrisulfonic acid (HPTS) and the base acetate. The proton/deuteron release is triggered by exciting HPTS with 400 nm femtosecond laser pulses. Probing the electronic and vibrational resonances of the photoacid, the conjugate photobase, the hydrated proton/deuteron and the accepting base with femtosecond visible and mid‐infrared pulses monitors the proton transfer. Two reaction channels are identified: 1) direct long‐range proton transfer over hydrogen‐bonded water bridges that connect the acid and base and 2) acid dissociation to produce fully solvated protons followed by proton scavenging from solution by acetate. We observe that the addition of salt affects the long‐range reaction pathway, and reduces both the rate at which protons are released to solution by HPTS and the rate at which solvated protons are scavenged from solution by acetate. We study the dependence of these effects on the nature and concentration of the dissolved salt.
Effect of Confinement on Proton‐Transfer Reactions in Water Nanopools
Authors: Tielrooij Klaas Jan , Cox M. Jocelyn , Bakker Huib J. 
Published: January 2009

AbstractProton transfer from the photoacid 8‐hydroxy‐1,3,6‐pyrenetrisulfonic acid (HPTS) to water is studied in reverse micelles with ionic (AOT=sodium dioctyl sulfosuccinate) and non‐ionic (BRIJ‐30=polyoxyethylene(4)lauryl ether) surfactants. The dynamics are studied by probing the transient electronic absorption and transient vibrational absorption, both with sub‐picosecond resolution. The reverse micelle sizes range from approximately 1.6 to 5.5 nm in diameter. For both surfactants it is found that the rate of proton transfer decreases with decreasing reverse micelle size, regardless of surfactant. In addition, for AOT reverse micelles, a fraction of the photoacid molecules exhibit non‐radiative decay, preventing proton transfer.
Climate Protection by an Alternative Use of Methane—The Carbon Moratorium
Authors: Kreysa Gerhard 
Published: January 2009

AbstractDespite a rising output, in the last few decades the known reserves of fossil energy resources have steadily increased. Additionally, there are in all likelihood tremendous reserves of methane hydrate. In view of the climate change, new means must be explored for its use as an energy source. Starting with an assessment of various options for dealing with the carbon cycle and thermodynamic considerations of methane chemistry, a new approach for the use of methane as energy source is developed in this Concept. After thermal methane cracking, only the energy content of the hydrogen is used and the carbon is stored safely and retrievably in disused coal beds. Arguments for the viability of a carbon moratorium of this kind are discussed.
TLR2 and TLR4 signaling shapes specific antibody responses to Salmonella typhi antigens
Authors: Cervantes‐Barragán Luisa , Gil‐Cruz Cristina , Pastelin‐Palacios Rodolfo , Lang Karl S. , Isibasi Armando , Ludewig Burkhard , López‐Macías Constantino 
Published: January 2009

AbstractTLR directly induce innate immune responses by sensing a variety of microbial components and are critical for the fine‐tuning of subsequent adaptive immune responses. However, their impact and mechanism of action on antibody responses against bacterial antigens are not yet fully understood. Salmonella enterica serovar Typhi (S. typhi) porins have been characterized as inducers of long‐lasting specific antibody responses in mice. In this report, we show that immunization of TLR4‐deficient (TLR4−/−), myeloid differentiating gene 88‐deficient and Toll/IL‐R domain‐containing adaptor‐inducing IFN‐β‐deficient mice with S. typhi porins led to significantly reduced B‐cell responses. TLR2−/− mice, as well, showed reduced IgG titers with a more pronounced impairment in the production of IgG3 anti‐porins antibodies. Adoptive transfer of TLR2−/−‐ or TLR4−/−‐B cells into B‐cell‐deficient mice revealed a direct effect of TLR4 on B cells for the primary IgM response, whereas stimulation of B cells via TLR2 was important for IgG production. Furthermore, S. typhi porins were found to efficiently elicit maturation of CD11c+ conventional DC. Taken together, S. typhi porins represent not only a suitable B‐cell antigen for vaccination, but exhibit potent TLR‐dependent stimulatory functions on B cells and DC, which help to further enhance and shape the antibody response.
Fibroblasts from different sites may promote or inhibit recruitment of flowing lymphocytes by endothelial cells
Authors: McGettrick Helen M. , Smith Emily , Filer Andrew , Kissane Stephen , Salmon Michael , Buckley Christopher D. , Rainger G. Ed , Nash Gerard B. 
Published: January 2009

AbstractWe examined the hypothesis that stromal fibroblasts modulate the ability of endothelial cells (EC) to recruit lymphocytes in a site‐specific manner. PBL were perfused over HUVEC that had been cultured with fibroblasts isolated from the inflamed synovium or the skin of patients with rheumatoid arthritis or osteoarthritis, or from normal synovium, with or without exposure to the inflammatory cytokines TNF‐α+IFN‐γ. Fibroblasts from inflamed synovium, but no others, caused unstimulated HUVEC to bind flowing lymphocytes. This adhesion was supported by α4β1‐VCAM‐1 interaction and stabilised by activation of PBL through CXCR4–CXCL12. Antibody neutralisation of IL‐6 during co‐culture effectively abolished the ability of EC to bind lymphocytes. Cytokine‐stimulated EC supported high levels of lymphocyte adhesion, through the presentation of VCAM‐1, E‐selectin and chemokine(s) acting through CXCR3. Interestingly, co‐culture with dermal fibroblasts caused a marked reduction in cytokine‐induced adhesion, while synovial fibroblasts had variable effects depending on their source. In the dermal co‐cultures, neutralisation of IL‐6 or TGF‐β caused partial recovery of cytokine‐induced lymphocyte adhesion; this was complete when both were neutralised. Exogenous IL‐6 was also found to inhibit response to TNF‐α+IFN‐γ. Normal stromal fibroblasts appear to regulate the cytokine‐sensitivity of vascular endothelium, while fibroblasts associated with chronic inflammation bypass this and develop a directly inflammatory phenotype. Actions of IL‐6 might be pro‐inflammatory or anti‐inflammatory, depending on the local milieu.
Anti‐retroviral effects of type I IFN subtypes in vivo
Authors: Gerlach Nicole , Gibbert Kathrin , Alter Christina , Nair Savita , Zelinskyy Gennadiy , James Cassandra M. , Dittmer Ulf 
Published: January 2009

AbstractType I IFN play a very important role in immunity against viral infections. Murine type I IFN belongs to a multigene family including 14 IFN‐α subtypes but the biological functions of IFN‐α subtypes in retroviral infections are unknown. We have used the Friend retrovirus model to determine the anti‐viral effects of IFN‐α subtypes in vitro and in vivo. IFN‐α subtypes α1, α4, α6 or α9 suppressed Friend virus (FV) replication in vitro, but differed greatly in their anti‐viral efficacy in vivo. Treatment of FV‐infected mice with the IFN‐α subtypes α1, α4 or α9, but not α6 led to a significant reduction in viral loads. Decreased splenic viral load after IFN‐α1 treatment correlated with an expansion of activated FV‐specific CD8+ T cells and NK cells into the spleen, whereas in IFN‐α4‐ and ‐α9‐treated mice it exclusively correlated with the activation of NK cells. The results demonstrate the distinct anti‐retroviral effects of different IFN‐α subtypes, which may be relevant for new therapeutic approaches.