bluuebunny/crossref_metadata_2025_split huggingface dataset:
Gas‐Phase Watson–Crick and Hoogsteen Isomers of the Nucleobase Mimic 9‐Methyladenine⋅2‐Pyridone
Authors: Frey Jann A. , Leist Roman , Müller Andreas , Leutwyler Samuel 
Published: June 2006

Abstract2‐Pyridone (pyridin‐2‐one) is a mimic of the uracil and thymine nucleobases, with only one NH and CO group. It provides a single H‐bonding site, compared to three for the canonical pyrimidine nucleobases. Employing the supersonically cooled 9‐methyladenine⋅2‐pyridone (9MAd⋅2PY) complex, which is the simplest base pair to mimic adenine‐uracil or adenine‐thymine, we show that its gas‐phase UV spectrum consists of contributions from two isomers. Based on the H‐bonding sites of 9‐methyladenine, these are the Watson–Crick and Hoogsteen forms. Combining two‐color two‐photon ionisation (2C‐R2PI), UV‐UV depletion and laser‐induced fluorescence spectroscopies allows separation of the two band systems, revealing characteristic intermolecular in‐plane vibrations of the two isomers. The calculated S0 and S1 intermolecular frequencies are in good agreement with the experimental ones. Ab initio calculations predict the Watson–Crick isomer to be slightly more stable (D0=−16.0 kcal mol−1) than the Hoogsteen isomer (D0=−15.0 kcal mol−1). The calculated free energies ΔfG0 of the Watson–Crick and Hoogsteen isomers agree qualitatively with the experimental isomer concentration ratio of 3:1.
First‐Principles Simulation of the Photoreaction of a Capped Azobenzene: The Rotational Pathway is Feasible
Authors: Nonnenberg Christel , Gaub Hermann , Frank Irmgard 
Published: June 2006

AbstractWe present first‐principles molecular dynamics simulations of azobenzene and a sterically hindered derivative in the first excited state. The restricted open‐shell Kohn–Sham (ROKS) approach is employed to describe the motion in the lowest excited state. The rotational pathway is observed in the molecular dynamics simulations for both azobenzene and its azacrown ether capped derivative.
Theoretical Characterization of the Gas‐Phase O3⋅⋅⋅HO Hydrogen‐Bonded Complex
Authors: Mansergas Alex , Anglada Josep M. 
Published: June 2006

AbstractWe report a theoretical study on two gas‐phase hydrogen‐bonded complexes formed between ozone and hydroxyl radical that have relevance to atmospheric chemistry. This study was carried out by using CASSCF, CASPT2, QCISD, and CCSD(T) theoretical approaches in conjunction with the 6‐311+G(2df,2p) and aug‐cc‐pVTZ basis sets. Both complexes have a planar structure and differ from each other in the orientation of the electronic density of the unpaired electron associated with the HO radical moiety. Our calculations predict their stabilities to be 0.87 and 0.67 kcal mol−1, respectively, at 0 K and show the importance of anharmonic effects in computing the red shift of the HO stretch originating from the hydrogen‐bonding interaction. We also report two transition states involving the movement of the HO moiety on the potential energy surfaces of these hydrogen‐bonded complexes.
Hydrology and dynamics of a polythermal (mostly cold) High Arctic glacier
Authors: Bingham Robert G. , Nienow Peter W. , Sharp Martin J. , Copland Luke 
Published: June 2006

AbstractTo improve our understanding of the interactions between hydrology and dynamics in mostly cold glaciers (in which water flow is limited by thermal regime), we analyse short‐term (every two days) variations in glacier flow in the ablation zone of polythermal John Evans Glacier, High Arctic Canada. We monitor the spatial and temporal propagation of high‐velocity events, and examine their impacts upon supraglacial drainage processes and evolving subglacial drainage system structure. Each year, in response to the rapid establishment of supraglacial–subglacial drainage connections in the mid‐ablation zone, a ‘spring event’ of high horizontal surface velocities and high residual vertical motion propagates downglacier over two to four days from the mid‐ablation zone to the terminus. Subsequently, horizontal velocities fall relative to the spring event but remain higher than over winter, reflecting channelization of subglacial drainage but continued supraglacial meltwater forcing. Further transient high‐velocity events occur later in each melt season in response to melt‐induced rising supraglacial meltwater inputs to the glacier bed, but the dynamic response of the glacier contrasts with that recorded during the spring event, with the degree of spatial propagation a function of the degree to which the subglacial drainage system has become channelized. Copyright © 2006 John Wiley & Sons, Ltd.
Brachiopod diversity patterns from Carboniferous to Triassic in South China
Authors: Shen Shu‐Zhong , Zhang Hua , LI Wen‐Zhong , Mu Lin , Xie Jun‐Fang 
Published: June 2006

AbstractIt has long been recognized that the trend of marine diversity from the Carboniferous to the Triassic includes an approximately 100‐myr‐long stable biodiversity stage ranging from the Late Carboniferous to the late Middle Permian, the most severe end‐Permian mass extinction in the Phanerozoic (pre‐Lopingian crisis and end‐Changhsingian mass extinction together), a bleak stage in the Early Triassic and a rapid recovery stage in the Middle Triassic. However, little attention has been paid to smaller diversity fluctuations among relatively stable stages in the Carboniferous and Permian. Here, we establish a database of the brachiopod fossil records from the Carboniferous to Triassic in South China, including 104 families, 373 genera, 2081 species recorded by 7948 occurrences with relatively detailed biostratigraphic controls. Analyses based on the raw taxonomic richness at familial, generic and specific levels, proportional and total extinction/origination/turnover rates, and rarefaction analyses for 21 different intervals from the Carboniferous to Triassic reveal that the brachiopod diversity trends can be generally divided into two distinctly different stages. Brachiopods were highly diversified during the Carboniferous and Permian Periods, whereas they were dramatically reduced in diversity after the end‐Changhsingian mass extinction. Brachiopods were abundant during the Early Carboniferous Tournaisian and Viséan, and were characterized by many genera extending from the Late Devonian. This was followed by a significant simple diversity decline in the Serpukhovian Stage. The Early Permian (either in Sakmarian or Artinskian) diversity decline previously perceived by coral and fusulinid workers is indicated by the raw generic and familial richness, and taxonomic richness per million years. However, it is not expressed by the rarefied brachiopod trajectory, which is probably affected by sampling effect or taxonomic selectivity. Brachiopods apparently declined from Capitanian to Early Wuchiapingian. Thus, the brachiopod diversity trajectory from Pennsylvanian Bashkirian to Late Guadalupian Capitanian generally characterises a long stable stage. Brachiopods are extremely abundant in the Late Wuchiapingian and Changhsingian in view of raw taxonomic richness, but a rarefied trajectory reveals a flat step following the pre‐Lopingian (end‐Guadalupian) crisis until the end‐Changhsingian mass extinction. Therefore, the previously widely perceived Lopingian radiation after the pre‐Lopingian crisis appears to be at least partly over‐stated. Brachiopods experienced a long bleak stage in the Early Triassic, followed by a rapid recovery in the Anisian, and reached their acme in the Norian, but never recovered to such a flourishing degree during the Carboniferous and Permian Periods. Brachiopods were eliminated in South China by the end‐Triassic withdrawal of the sea from this region. Copyright © 2006 John Wiley & Sons, Ltd.
Effect of syntactic similarity on cortical activation during second language processing: A comparison of English and Japanese among native Korean trilinguals
Authors: Jeong Hyeonjeong , Sugiura Motoaki , Sassa Yuko , Haji Tomoki , Usui Nobuo , Taira Masato , Horie Kaoru , Sato Shigeru , Kawashima Ryuta 
Published: June 2006

AbstractIn this study of native Korean trilinguals we examined the effect of syntactic similarity between first (L1) and second (L2) languages on cortical activation during the processing of Japanese and English, which are, respectively, very similar to and different from Korean. Subjects had equivalent proficiency in Japanese and English. They performed auditory sentence comprehension tasks in Korean, Japanese, and English during functional MRI (fMRI). The bilateral superior temporal cortex was activated during the comprehension of three languages. The pars triangularis of the left inferior frontal gyrus (IFG) was additionally activated for L2 processing. Furthermore, the right cerebellum, the pars opercularis of the left IFG, and the posteriomedial part of the superior frontal gyrus were activated during the English tasks only. We observed significantly greater activation in the pars opercularis of the left IFG, the right cerebellum, and the right superior temporal cortex during the English than Japanese task; activation in these regions did not differ significantly between Korean and Japanese. Differential activation of the pars opercularis of the left IFG and the right cerebellum likely reflects syntactic distance and differential activation in the right superior temporal cortex may reflect the prosodic distance between English from Korean and Japanese. Furthermore, in the pars oparcularis of the left IFG and the right cerebellum, significant negative correlation between the activation and duration of exposure was observed for English, but not for Japanese. Our research supports the notion that linguistic similarity between L1 and L2 affects the cortical processing of second language. Hum Brain Mapp, 2007. © 2006 Wiley‐Liss, Inc.
Influence of body segment position during in‐phase and antiphase hand and foot movements: A kinematic and functional MRI study
Authors: Rocca Maria A. , Gatti Roberto , Agosta Federica , Tortorella Paola , Riboldi Elisa , Broglia Paola , Filippi Massimo 
Published: June 2006

AbstractBehavioral studies have provided important insights into the mechanisms governing interlimb coordination. In this study, we combined kinematic and functional magnetic resonance imaging (fMRI) analysis to investigate the brain cortical and subcortical areas involved in interlimb coordination and the influence of direction of movement and of body segment position on the activity of those areas. Fifteen right‐handed healthy subjects were studied while performing cyclic in‐phase and antiphase hand and foot movements with the dominant, right limbs, with the upper limb positioned either prone or supine, and in front or behind with respect to the trunk. When contrasting antiphase to in‐phase movements, fMRI analysis demonstrated an increased recruitment of a widespread sensorimotor network (including regions in the frontal and parietal lobes, bilaterally, the cingulated motor area, the thalami, the visual cortex, and the cerebellum) considered to function in motor, sensory, and multimodal integration processing. When contrasting the anterior to the posterior position of the upper limb with respect to the trunk, we found different recruitment patterns in the frontal and parietal regions as well as the preferential recruitment of the basal ganglia, the insula, and the cerebellum during the first condition and of regions located in the temporal lobes during the second one. Different brain areas are engaged at a different extent during interlimb coordination. In addition to the relative difficulty of the movement, the different cognitive and sensorial loads needed to control and perform the motor act might be responsible for these findings. Hum Brain Mapp, 2007. © 2006 Wiley‐Liss, Inc.
Influence of Nitinol wire surface treatment on oxide thickness and composition and its subsequent effect on corrosion resistance and nickel ion release
Authors: Clarke B. , Carroll W. , Rochev Y. , Hynes M. , Bradley D. , Plumley D. 
Published: June 2006

AbstractMedical implants and devices are now used successfully in surgical procedures on a daily basis. Alloys of nickel and titanium, and in particular Nitinol are of special interest in the medical device industry, because of their shape memory and superelastic properties. The corrosion behavior of nitinol in the body is also of critical importance because of the known toxicological effects of nickel. The stability of a NiTi alloy in the physiological environment is dependant primarily on the properties of the mostly TiO2 oxide layer that is present on the surface. For the present study, a range of nitinol wires have been prepared using different drawing processes and a range of surface preparation procedures. It is clear from the results obtained that the wire samples with very thick oxides also contain a high nickel content in the oxide layer. The untreated samples with the thicker oxides show the lowest pitting potential values and greater nickel release in both long and short‐term experiments. It was also found that after long‐term immersion tests breakdown potentials increased for samples that exhibited lower values initially. From these results it would appear that surface treatment is essential for the optimum bioperformance of nitinol. © 2006 Wiley Periodicals, Inc. J Biomed Mater Res, 2006
Synthesis of silk fibroin‐insulin bioconjugates and their characterization and activities in vivo
Authors: Zhang Yu‐Qing , Ma Yan , Xia Yun‐Yue , Shen Wei‐De , Mao Jian‐Ping , Zha Xin‐Min , Shirai Koji , Kiguchi Kenji 
Published: June 2006

AbstractThe regenerated liquid silk fibroin with an average molecular mass of about 60 kDa consists of 18 kinds of amino acids containing ∼10% of polar amino acids with hydroxyl and amino groups such as serine and lysine. The liquid silk fibroin is coupled covalently with insulin molecules through these strongly polar side groups by using glutaraldehyde. The physicochemical properties of the silk fibroin‐insulin (SF‐Ins) bioconjugates were investigated by enzyme‐linked immunosorbent assay for the quantitative measurement of insulin. The biological activities of the insulin bioconjugates were characterized in vitro and in vivo. The SF‐Ins constructs obtained by 5 h of covalent crosslinking showed much higher recovery (about 70%) and in vitro stability in human serum than bovine serum albumin‐insulin (BSA‐Ins) derivatives. The results in human serum indicated that the half‐life in vitro of the biosynthesized SF‐Ins derivatives was 2.1 and 1.7 times more than that of BSA‐Ins conjugates and native insulin, respectively. The immunogenicity of the regenerated silk fibroin and the antigenicity of silk fibroin‐modified insulin were not observed in both rabbits and rats. The pharmacological activity of the SF‐Ins bioconjugates in diabetic rats evidently lengthened and was about 3.5 times as long as that of the native insulin, nearly 21 h. The bioconjugation of insulin with the regenerated silk fibroin greatly improved its physicochemical and biological stability. © 2006 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2006
Community‐acquired pneumonia: A practical approach to management for the hospitalist
Authors: Sharpe Bradley A. , Flanders Scott A. 
Published: June 2006

AbstractCommunity‐acquired pneumonia (CAP) is common, and inpatient physicians should be familiar with the most current evidence about and guidelines for CAP management. Our conclusions and recommendations include: Streptococcus pneumoniae is the most common identified cause of CAP requiring hospitalization, whereas Legionella pneumophila is a common cause of severe CAP. The chest radiograph remains an essential initial test in the diagnosis of CAP and should be supplemented by blood cultures sampled prior to antibiotic therapy and sputum for gram stain and culture if a high‐quality specimen can be rapidly processed. Once the diagnosis is made, the Pneumonia Severity Index (PSI) should be used to optimize the location of treatment and to provide prognostic information. Absent other mitigating factors, patients in PSI risk classes I, II, and III can safely be treated as outpatients. Hospitalized patients with CAP should be treated promptly with empiric antibiotics. Nonsevere pneumonia should be treated with a parenteral β‐lactam plus either doxycycline or a macrolide. Patients admitted to the intensive care unit should be treated with a β‐lactam plus either a macrolide or a fluoroquinolone as well as be evaluated for pseudomonal risk factors. Most patients with nonsevere CAP reach clinical stability in 2–3 days and should be considered for a switch to oral therapy and discharge shortly thereafter. Patients should receive pneumococcal vaccination, influenza vaccination, and tobacco cessation counseling prior to discharge if eligible. Multiple quality indicators are measured and publicly reported in the management of CAP, which provides hospitals with an opportunity to improve care processes and patient outcomes. Journal of Hospital Medicine 2006;1:177–190. © 2006 Society of Hospital Medicine.
Effect of using local arterial input functions on cerebral blood flow estimation
Authors: Lorenz Cory , Benner Thomas , Lopez Chloe Joan , Ay Hakan , Zhu Ming Wang , Aronen Hannu , Karonen Jari , Liu Yawu , Nuutinen Juho , Sorensen A. Gregory 
Published: June 2006

AbstractPurposeTo investigate a previously developed method for perfusion‐weighted MRI (PWI) cerebral blood flow (CBF) estimation that uses local arterial input functions (AIFs) in stroke patients, and determine its ability to correct delay and/or dispersion (D/D) errors.Materials and MethodsAnalysis was performed on dynamic susceptibility contrast data from 36 stroke patients, and CBF maps were calculated with global‐ and local‐AIF techniques using standard SVP based methods. The ratios of these maps were calculated and the mean ratios were calculated for voxels with both normal and abnormal time to peak or width. The locations of the voxels with high locally‐defined to globally‐defined CBF ratios were also mapped and the average underlying concentration‐time curves for these voxels were calculated.ResultsThe ratio of CBF estimates based on local AIFs to global AIFs was on average increased for D/D voxels. The voxels in which this ratio was high were commonly concentrated in the ipsilateral hemisphere, and these voxels also displayed underlying concentration‐time curves that showed delay or dispersion. Conversely, there were no such findings based on high globally‐defined to locally‐defined CBF ratios.ConclusionThe local‐AIF technique results in an increase in the calculated CBF values for tissues with D/D, consistent with a reduction in the errors associated with D/D. J. Magn. Reson. Imaging 2006. © 2006 Wiley‐Liss, Inc.
Combined diffusion‐weighted and dynamic contrast‐enhanced MRI for prostate cancer diagnosis—Correlation with biopsy and histopathology
Authors: Kozlowski Piotr , Chang Silvia D. , Jones Edward C. , Berean Kenneth W. , Chen Henry , Goldenberg S. Larry 
Published: June 2006

AbstractPurposeTo determine whether the combination of diffusion‐weighted (DW) and dynamic contrast‐enhanced (DCE) MRI provides higher diagnostic sensitivity for prostate cancer than each technique alone.Materials and MethodsFourteen patients with a clinical suspicion of prostate cancer underwent endorectal MRI on a 1.5T scanner prior to transrectal ultrasound (TRUS)‐guided biopsies. The average values of the apparent diffusion coefficient (ADC, calculated from b‐values of 0 and 600), Ktrans, ve, maximum gadolinium (Gd) concentration, onset time, mean gradient, and maximum enhancement were determined. Correlation with histology was based on biopsy (six patients) and prostatectomy specimen (eight patients) results. The Tukey‐Kramer test was used for statistical analysis.ResultsThe average values of all MRI parameters, except ve and maximum Gd concentration, showed significant differences between tumor and normal prostate. The sensitivity and specificity values were respectively 54% (35–72%) and 100% (95–100%) for the ADC data, and 59% (39–77%) and 74% (63–83%) for the DCE data. When both ADC and DCE results were combined, the sensitivity increased to 87% (68–95%) and specificity decreased to 74% (62–83%).ConclusionAll but two DW‐ and DCE‐MRI parameters showed significant differences between tumor and normal prostate. Combining both techniques provides better sensitivity, with a small decrease in specificity. J. Magn. Reson. Imaging 2006. © 2006 Wiley‐Liss, Inc.
Staggered ethane changes to eclipsed conformation upon adsorption
Authors: Priebe A. , Pucci A. , Akemann W. , Grabhorn H. , Otto A. 
Published: June 2006

AbstractPrevious comparison of the infrared and Raman spectra of bulk and adsorbed C2H6 has shown that the CC axis is parallel to the local surface of Cu. The conformation of ethane in thick condensed layers is staggered. The clear appearance of a Raman band of a bending mode, not Raman active in the staggered conformation, proves that ethane is adsorbed in eclipsed conformation on silver, indium, and potassium, and probably on other quasi‐free electron metals. A relatively low‐lying Raman band is assigned to the 0 to 2 internal torsional rotation, with about half the frequency in the staggered conformation. This is to be expected when forcing the molecule from staggered‐ to eclipsed conformation by adsorption. Copyright © 2006 John Wiley & Sons, Ltd.
Cervical dystonia responsive to acoustic and galvanic vestibular stimulation
Authors: Rosengren Sally M. , Colebatch James G. 
Published: June 2006

AbstractAbstract: We examined the effects of acoustic and galvanic vestibular stimulation in a patient with cervical dystonia. Acoustic stimulation consisted of three conditions: “baseline” (no stimulation), “vestibular” (500 Hz bone‐conducted tone bursts), and “control” (5,000 Hz tone bursts). Rectified electromyographic activity in the sternocleidomastoid was measured. Galvanic stimulation (1.5–2.5 mA current steps) was delivered to the mastoids, and head acceleration was measured. Vestibular acoustic stimulation reduced neck muscle activity between 16% and 44% (P < 0.001), and galvanic stimulation reduced head acceleration by 22.5% (P = 0.028). The patient reported subjective improvement in head control. Vestibular stimulation can reduce neck muscle activity in cervical dystonia and give symptomatic relief. © 2006 Movement Disorder Society
Requirements for effective IgE cross‐linking on mast cells and basophils
Authors: Knol Edward F. 
Published: June 2006

AbstractThis article reviews the characteristics of high affinity IgE receptors (FcεRI) and their role in the response to allergenic proteins. The requirements for successful cross‐linking of FcεRI on basophils and mast cells and subsequent degranulation by allergenic proteins will be explained in detail. Methods for in vitro analysis of allergen‐induced mast cell and basophil degranulation will be described and issues/problems in applying these methods will be discussed. Finally, implications for manipulation of protein allergens will be discussed.