bluuebunny/crossref_metadata_2025_split huggingface dataset:
Diazoalkane Reduction for the Synthesis of Uranium Hydrazonido Complexes
Authors: Matson Ellen M. , Fanwick Phillip E. , Bart Suzanne C. 
Published: August 2012

AbstractThe reactivity of the uranium(III) alkyl Tp*2UCH2Ph (1) toward diazoalkanes is reported. Addition of 1 equiv. N2CPh2 produces 0.5 equiv. bibenzyl, along with Tp*2U(N2CPh2) (2). This species is dynamic in solution at room temperature and rapidly interconverts between the η1‐ and η2 isomers as determined by variable‐temperature 1H NMR spectroscopy. X‐ray crystallographic analysis at low temperature shows exclusively the η2 isomer, which features a short U–N multiple bond analogous to an imido species. The η1 isomer reacts quantitatively with aldehydes and ketones through multiple bond metathesis to produce Tp*2U(O) and the corresponding ketazine. Treatment of 1 with N2CHSiMe3 generates 0.5 equiv. bibenzyl and the η1 isomer Tp*2U(N2CHSiMe3) (3). This species is unstable over the course of hours, and there is no spectroscopic evidence for the η2 isomer. Tp*2U(η1‐N2CHSiMe3) can be trapped by addition of phenylacetylene by a [2+2] cycloaddition to afford the uranium(IV) metallacycle Tp*2U[(N‐N = CHSiMe3)CHCPh] (4). Crystallographic data for 4 are presented.
Spectroscopic and Structural Characterization of Noninnocent Mixed‐Ligand Oxidovanadium(V) Complexes
Authors: Maurya Mannar R. , Bisht Manisha , Chaudhary Nikita , Kumar Amit , Avecilla Fernando , Costa Pessoa João 
Published: August 2012

AbstractThe reaction between [VIVO(acac)(L)] and the potentially noninnocent ligands catechol (H2cat/cat2–) and benzohydroxamic acid (H2bha/bha2–), where HL = Hpydx‐aebmz, Hpydx‐dmen, Hpydx‐aepy [ONN donor Schiff bases obtained by condensation of pyridoxal and 2‐(2‐aminoethyl)benzimidazole (Hpydx‐aebmz), 2‐(2‐aminoethyl)pyridine (Hpydx‐aepy), or N,N‐dimethylethylenediamine (Hpydx‐dmen)], or HL = Hpan [1‐(2‐pyridylazo)‐2‐naphthol], in equimolar amounts results in the formation of the distorted octahedral complexes [VVO(cat)(L)] and [VVO(bha)(L)]. The molecular structure of [VO(bha)(pydx‐dmen)] is determined by single‐crystal X‐ray diffraction and confirms the distorted octahedral geometry as well as the ONN and OO binding modes of pydx‐dmen– and bha2–, respectively, in their binding to the VVO centre. The noninnocent catechol2– and bha2– ligands play significant roles in the electronic properties of the metal complexes investigated by UV/Vis, IR, and 51V NMR spectroscopy. Evidence for the noninnocent behavior of catechol2– and bha2– ligands was obtained; the [VVO(cat)(L)] and [VVO(bha)(L)] complexes exhibit 51V NMR resonances (δV) in the range +535 to –10 ppm and intense ligand‐to‐metal charge‐transfer bands in the visible and near infrared range. The observed δV chemical shifts linearly correlate with the inverse of the energies of the LMCT transitions.
Range imaging: a new method for high‐resolution topographic measurements in small‐ and medium‐scale field sites
Authors: Nitsche Manuel , Turowski Jens M. , Badoux Alexandre , Rickenmann Dieter , Kohoutek Tobias K. , Pauli Michael , Kirchner James W. 
Published: August 2012

ABSTRACTTopographic measurements are essential for the study of earth surface processes. Three‐dimensional data have been conventionally obtained through terrestrial laser scanning or photogrammetric methods. However, particularly in steep and rough terrain, high‐resolution field measurements remain challenging and often require new creative approaches. In this paper, range imaging is evaluated as an alternative method for obtaining surface data in such complex environments. Range imaging is an emerging time‐of‐flight technology, using phase shift measurements on a multi‐pixel sensor to generate a distance image of a surface. Its suitability for field measurements has yet not been tested. We found ambient light and surface reflectivity to be the main factors affecting error in distance measurements. Low‐reflectivity surfaces and strong illumination contrasts under direct exposure to sunlight lead to noisy distance measurements. However, regardless of lighting conditions, the accuracy of range imaging was markedly improved by averaging multiple images of the same scene. For medium ambient lighting (shade) and a light‐coloured surface the measurement uncertainty was approximately 9 mm. To further test the suitability of range imaging for field applications we measured a reach of a steep mountain stream with a horizontal resolution of approximately 1 cm (in the focal plane of the camera), allowing for the interpolation of a digital elevation model on a 2 cm grid. Comparison with an elevation model obtained from terrestrial laser scanning for the same site revealed that both models show similar degrees of topographic detail. Despite limitations in measurement range and accuracy, particularly at bright ambient lighting, range imaging offers three‐dimensional data in real time and video mode without the need of post‐processing. Therefore, range imaging is a useful complement or alternative to existing methods for high‐resolution measurements in small‐ to medium‐scale field sites. Copyright © 2012 John Wiley & Sons, Ltd.
Modulation of biocompatibility on poly(vinylidene fluoride) and polysulfone by oxygen plasma treatment and dopamine coating
Authors: Mangindaan Dave , Yared Ivan , Kurniawan Hengky , Sheu Joen‐Rong , Wang Meng‐Jiy 
Published: September 2012

AbstractPoly(vinylidene fluoride) (PVDF) and polysulfone (PSf) are two polymers with excellent mechanical properties but insufficient biocompatibility mainly due to their surface hydrophobicity. This study has applied oxygen plasma treatments and dopamine coating on the two polymers and investigated the changes of the surface properties and interactions with mammalian cells. All modification steps were verified by means of Electron Spectroscopy for Chemical Analysis and contact angle measurements. Surface topology of materials and biomolecules was studied by atomic force measurements (AFM) and scanning electron microscopy (SEM). Protein adsorption was quantified by fluorescent imaging and Bradford method. The results showed that O2 plasma altered the surface hydrophilicity effectively on PSf and more than two folds of oxidation were obtained, when compared with the pristine one. The change of surface wettability was less significant on the O2 plasma treated PVDF due to less oxidation extent, which was identified by analyzing the chemical compositions. The provided functionalized PVDF and PSf surfaces were tested with bovine serum albumin and L‐929 mouse fibroblasts to evaluate the effects of surface modifications on protein adsorption and cell attachments. The biocompatibility was effectively promoted to fourfold and twofold on the hydrophobic PVDF and PSf by applying O2 plasma treatments within short treatment time. Moreover, the simple immobilization of polymers in dopamine solution resulted in hydrophilic surface coating with stability that caused threefold and twofold increases of biocompatibility on PVDF and PSf correspondingly. © 2012 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 100A:3177–3188, 2012.
Strontium calcium phosphate for the repair of leporine (Oryctolagus cuniculus) ulna segmental defect
Authors: Mohan Beena G. , Shenoy Sachin J. , Babu Suresh S. , Varma H. K. , John Annie 
Published: September 2012

AbstractScaffolds to aid in repair, replacement, or regeneration of bony tissues have been developed using a wide spectra of materials. Under clinical conditions, assessment of healing and implant placement is guided radiographically. In this context, strontium's role in osteostimulation and its relevance in radio‐opacity are known. Therefore to aid in assessment and to ensure tissue regeneration, a bone mimetic porous strontium calcium phosphate (SrCaPO4) was synthesized in‐house, which was non‐cytotoxic (ISO 10993 (Part V) and subsequently characterized for its crystallinity, functional groups, and 3D porous topography. Furthermore, to assess the feasibility of the bioactive ceramic scaffolds in bone repair, SrCaPO4 and hydroxyapatite (HA—Control) scaffolds were implanted in the segmental ulna bone critical‐sized defect (1.5 cm) of New Zealand White Rabbits (leporine model—Oryctolagus cuniculus) for a period of 4 and 12 weeks, respectively. Healing of the defects was uneventful without any inflammation or infection. Radio‐opacity of SrCaPO4 within the defect site enabled easy assessment of implant placement and osteointegration. Again, histological evaluation coupled with micro‐CT and histomorphometrical analysis indicated that SrCaPO4 favored significant de novo bone formation in par with material degradation at 4 and 12 weeks post‐implantation compared to HA at 4 and 12 weeks. Investigations on this radio‐opaque SrCaPO4 established its role in the repair of critical‐sized segmental defects, proposing it as a suitable bone substitute for clinical reconstructive surgery with easy radiographic evaluation. © 2012 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 101A:261–271, 2013.
Evaluation of hydrogels for bio‐printing applications
Authors: Murphy Sean V. , Skardal Aleksander , Atala Anthony 
Published: September 2012

AbstractIn the United States alone, there are approximately 500,000 burn injuries that require medical treatment every year. Limitations of current treatments necessitate the development of new methods that can be applied quicker, result in faster wound regeneration, and yield skin that is cosmetically similar to undamaged skin. The development of new hydrogel biomaterials and bioprinting deposition technologies has provided a platform to address this need. Herein we evaluated characteristics of twelve hydrogels to determine their suitability for bioprinting applications. We chose hydrogels that are either commercially available, or are commonly used for research purposes. We evaluated specific hydrogel properties relevant to bioprinting applications, specifically; gelation time, swelling or contraction, stability, biocompatibility and printability. Further, we described regulatory, commercial and financial aspects of each of the hydrogels. While many of the hydrogels screened may exhibit characteristics suitable for other applications, UV‐crosslinked Extracel, a hyaluronic acid‐based hydrogel, had many of the desired properties for our bioprinting application. Taken together with commercial availability, shelf life, potential for regulatory approval and ease of use, these materials hold the potential to be further developed into fast and effective wound healing treatments. © 2012 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 101A:272–284, 2013.
Nucleation and growth of apatite on an anatase layer irradiated with UV light under different environmental conditions
Authors: Uetsuki Keita , Nakai Shinsuke , Shirosaki Yuki , Hayakawa Satoshi , Osaka Akiyoshi 
Published: September 2012

AbstractImplant surfaces must sometimes be modified to form strong bonds to host tissues. The method of depositing an anatase layer on chemically pure titanium by chemical oxidation with H2O2 and subsequent calcination (CHT) is known to deposit apatite under physiological conditions; it thus exhibits bone‐bonding ability. UV irradiation should affect the bonding ability because the CHT anatase layer would experience certain chemical modifications, such as a decrease or an increase in the number of TiOH and TiO(H)Ti sites; these sites are considered active sites for apatite nucleation. When in vitro apatite deposition was examined, using Kokubo's simulated body fluid, UV irradiation in air reduced the apatite‐forming ability of the CHT anatase layer, and UV irradiation on the samples in water enhanced the ability. These results were correlated to changes in the TiOH and TiO(H)Ti sites, as determined by O 1s X‐ray photoelectron spectroscopy. Analysis of the number and size of the semi‐spherical apatite particles and their surface coverage led to a model: proper assembly of the TiOH and TiO(H)Ti sites should only give rise to the induction of apatite nucleation, analogous to topotaxy effects. © 2012 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 101A: 712–719, 2013.
Wear particles promote endotoxin tolerance in macrophages by inducing interleukin‐1 receptor‐associated kinase‐M expression
Authors: Zhang Yangchun , Yu Shiming , Xiao Jianhong , Hou Changhe , Li Ziqing , Zhang Ziji , Zhai Qiyi , Lehto Matti , Konttinen Yrjö T. , Sheng Puyi 
Published: September 2012

AbstractToll‐like receptors (TLRs) recognizing pathogen‐associated molecular patterns (PAMP) play a role in local immunity and participate in implant‐associated loosening. TLRs‐mediated signaling is regulated by interleukin‐1 receptor‐associated kinase‐M (IRAK‐M). Our previous studies have proved that IRAK‐M is induced by wear particles in macrophages from periprosthetic tissues. In this study, the IRAK‐M‐related mechanisms were further explored by lipopolysaccharide (LPS) and/or titanium (Ti) particles stimulations and small interfering RNAs (siRNAs). The protein level of IRAK‐M was studied using western blotting and tumor necrosis factor‐α (TNF‐α), and interleukin‐1β (IL‐1β) levels were measured using ELISA. Results showed that in RAW264.7 cells stimulated by LPS after Ti particle pre‐exposure, IRAK‐M was slightly changed, compared with LPS stimulation. And levels of TNF‐α and IL‐1β in cultures stimulated by LPS first after Ti particle pre‐exposure were lower than in the other two groups which were stimulated by LPS with or without Ti particles (p < 0.001), whereas there were no statistic differences between the later two (p > 0.05). The cytokines were lowest in Ti particles alone stimulation. After siRNAs silenced, IRAK‐M‐deficient cells exhibited increased expression of the cytokines in LPS stimulation after Ti particle pre‐exposure and when stimulated with Ti particles alone. Our findings suggest that debris‐induced IRAK‐M decreases foreign body reactions, but at the same time, the over‐expression of IRAK‐M may also be detrimental on local intrusion of PAMPs or bacteria, negatively regulates the LPS‐induced and TLRs‐mediated inflammation and results in immunosuppression in periprosthetic tissue, which may predispose to implant‐associated infections. © 2012 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 101A: 733–739, 2013.
Dopamine‐assisted immobilization of hydroxyapatite nanoparticles and RGD peptides to improve the osteoconductivity of titanium
Authors: Chien Chih‐Yuan , Liu Tse‐Ying , Kuo Wei‐Hsuan , Wang Meng‐Jiy , Tsai Wei‐Bor 
Published: September 2012

AbstractHydroxyapatite (HAp) coating on orthopedic implants is a common strategy to increase osteointegration. In this work, a facile deposition method based on dopamine polymerization was developed for preparation of HAp‐coated titanium substrates for orthopedic applications. Nanostructured HAp was mixed with an alkaline dopamine solution and then deposited onto titanium to form a dopamine/HAp ad‐layer. The deposition of dopamine/HAp greatly enhanced the adhesion, proliferation, and mineralization of osteoblasts. Furthermore, RGD‐containing peptides were immobilized to dopamine/HAp coated titanium and further enhanced cell adhesion and osteogenic differentiation. In conclusion, this facile dopamine‐assisted surface modification method shows a great potential for orthopedic and dental applications. © 2012 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 101A: 740–747, 2013.
Subthalamic stimulation improves the cerebral hemodynamic response to the cold pressure test in patients with Parkinson's disease
Authors: Rätsep Tõnu , Asser Toomas 
Published: September 2012

AbstractPurpose.Disturbances of the autonomic nervous system are common in patients with Parkinson's disease (PD) but the effect of deep brain stimulation of the subthalamic nucleus on cerebrovascular reactivity is not entirely known.Methods.Seven patients in an advanced stage of the disease and seven healthy age‐matched controls participated in the study, which took place after one night of drug withdrawal. Cerebral blood flow velocity was continuously monitored on both sides with transcranial Doppler ultrasound, and cerebrovascular reactivity (CR) was evaluated with the cold pressure test. The measurements were repeated and compared during the stimulation‐on and ‐off phases.Results.The PD patients had significantly higher CR values in the stimulation‐on than ‐off conditions (15.1% ± 6.9 versus 9.4% ± 6.2; p = 0.03). CR values were higher in controls than in patients in the stimulation‐off condition (20.4% ± 12.5 versus 9.4% ± 6.2; p = 0.007) without a significant difference with the stimulation‐on phase.Conclusions.CR, evaluated by the response to the cold pressure test, is impaired in patients with advanced PD and improved by subthalamic nucleus. © 2012 Wiley Periodicals, Inc. J Clin Ultrasound, 2012.
Locally Symmetric Graphs of Girth 4
Authors: Perles Micha A. , Martini Horst , Kupitz Yaakov S. 
Published: September 2012

AbstractWe classify the family of connected, locally symmetric graphs of girth 4 (finite and infinite). They are all regular, with the exception of the complete bipartite graph . There are, up to isomorphism, exactly four such k‐regular graphs for every , one for , two for , and exactly three for every infinite cardinal k. In the last paragraph, we consider locally symmetric graphs of girth >4.
Reproducibility of 1H MR spectroscopy of hip bone marrow at 3 tesla
Authors: Pansini Vittorio M. , Monnet Aurélien , Salleron Julia , Penel Guillaume , Migaud Henry , Cotten Anne 
Published: September 2012

AbstractPurpose:To assess the reproducibility of fat content (FC) values in five different anatomical areas of proximal femur by the means of 1H 3 Tesla MR spectroscopy and to evaluate if any statistical difference exists when comparing right side to left side FC values in the same individual.Materials and Methods:Thirty‐three volunteers underwent unilateral 1H MR spectroscopy of the hip. From 1 to 4 weeks later, they repeat the MR examination of the same hip to assess the reproducibility of the technique. Fifteen other volunteers underwent a bilateral 1H MR hip spectroscopy to compare right and left side FC values.Results:The reproducibility of 1H MR spectroscopy was high in all the anatomic areas considered, ranging from 0.90 to 0.98. No statistically significant difference was found when the fat content values on the right side were compared to those on the left side. (P > 0.16).Conclusion:The 3 Tesla 1H MR spectroscopy of hip bone marrow permitted highly reproducible fat content values in all the five anatomic areas examined. No statistical significant difference existed when comparing fat content values of the right side to those of the left side in the same individual. J. Magn. Reson. Imaging 2012; 36:1445–1449. © 2012 Wiley Periodicals, Inc.
Optimizing lavage during knee arthroscopy: A three‐dimensional MRI study
Authors: Nord Russell M. , Badowski Natalie , Elkins Christopher , Alley Marcus , Harris Alex H.S , Dragoo Jason L. 
Published: September 2012

AbstractPurpose:To determine the best positioning and the resulting fluid flow patterns inside the knee during arthroscopy, reducing the surgical morbidity associated with the arthroscopic irrigation and debridement of a septic knee joint.Materials and Methods:Three‐dimensional MRI, using an MRI‐compatible human cadaveric knee arthroscopic model, generated fluid flow diagrams and velocity vector data. This was analyzed for six different arthroscopic configurations and at six different locations within the knee joint.Results:At any one static arthroscopic position, fluid flow velocity differed at the various locations in the knee, often with statistically significantly greater flow at one location over another. In general, flow was greatest at the location at which the inflow cannula terminated and preferentially flowed directly to the outflow cannula location, neglecting spaces in the knee that were not on this direct path. Three‐portal arthroscopy provided no benefit over two‐portal arthroscopy.Conclusion:To maximize arthroscopic lavage throughout all compartments in the knee, the arthroscopist must individually enter each space in the knee. Static arthroscopy in the setting of knee sepsis may lead to inadequate flow in certain areas of the knee and may lead to treatment failure. Three‐portal arthroscopy does not improve lavage efficiency. J. Magn. Reson. Imaging 2013;37:201–207. © 2012 Wiley Periodicals, Inc.
Mechanism of intraseasonal oceanic signature in the region off southern tip of India during boreal summer
Authors: Jayakumar A. , Gnanaseelan C. , Sabin T. P. 
Published: September 2012

ABSTRACTSea surface temperature (SST) in the region off southern tip of India (STI, 75–83°E, 5–8°N) exhibited a prominent variability in the intraseasonal time scale (both 30–90 d and 10–30 d band) during boreal summer. Mechanisms associated with this intraseasonal variability are studied using three‐dimensional ocean general circulation model (OGCM) sensitivity experiments, satellite observed outgoing longwave radiation, SST and winds for the period 1998–2007. The background oceanic structure of the STI characterized by a shallow thermocline and moderate mixed layer provided ideal conditions for strong oceanic sub‐surface processes. The model mixed layer heat budget reveals that the oceanic processes such as horizontal advection and vertical processes are the dominant mechanisms in the STI region as compared with air‐sea flux. Sensitivity experiments with the OGCM reveals that the ocean dynamical processes contribute to most of the intraseasonal SST variability and the wind stress contributes to 85% of the variability whereas surface flux contributes to only 15% for the 30–90 d SST variability. Higher amplitude of surface flux perturbation and its contribution to SST in the 10–30 d as compared with the 30–90 d band are evident in the model experiment and are consistent with the observational analysis. There is year‐to‐year variability in the relative role of horizontal and vertical processes for different intraseasonal SST events over STI.
Flooding of the continental shelves as a contributor to deglacial CH4 rise
Authors: Ridgwell Andy , Maslin Mark , Kaplan Jed O. 
Published: August 2012

AbstractThe transition from the last glacial and beginning of Bølling–Allerød and Pre‐Boreal periods in particular is marked by rapid increases in atmospheric methane (CH4) concentrations. The CH4 concentrations reached during these intervals, ∼650–750 ppb, is twice that at the last glacial maximum and is not exceeded until the onset of industrialization at the end of the Holocene. Periods of rapid sea‐level rise as the Last Glacial Maximum ice sheets retreated and associated with ‘melt‐water pulses’ appear to coincide with the onset of elevated concentrations of CH4, suggestive of a potential causative link. Here we identify and outline a mechanism involving the flooding of the continental shelves that were exposed and vegetated during the glacial sea‐level low stand and that can help account for some of these observations. Specifically, we hypothesize that waterlogging (and later, flooding) of large tracts of forest and savanna in the Tropics and Subtropics during the deglacial transition and early Holocene would have resulted in rapid anaerobic decomposition of standing biomass and emission of methane to the atmosphere. This novel mechanism, akin to the consequences of filling new hydroelectric reservoirs, provides a mechanistic explanation for the apparent synchronicity between rate of sea‐level rise and occurrence of elevated concentrations of ice core CH4. However, shelf flooding and the creation of transient wetlands are unlikely to explain more than ∼60 ppb of the increase in atmospheric CH4 during the deglacial transition, requiring additional mechanisms to explain the bulk of the glacial to interglacial increase. Similarly, this mechanism has the potential also to play some role in the rapid changes in atmospheric methane associated with the Dansgaard–Oeschger cycles. Copyright © 2012 John Wiley & Sons, Ltd.