bluuebunny/crossref_metadata_2025_split huggingface dataset:
The linear arboricity of planar graphs of maximum degree seven is four
Authors: Wu Jian‐Liang , Wu Yu‐Wen 
Published: May 2008

AbstractThe linear arboricity of a graph G is the minimum number of linear forests which partition the edges of G. Akiyama et al. conjectured that $\lceil {\Delta {({G})}\over {2}}\rceil \leq {la}({G}) \leq \lceil {\Delta({G})+{1}\over {2}}\rceil$ for any simple graph G. Wu wu proved the conjecture for a planar graph G of maximum degree $\Delta\not={{7}}$. It is noted here that the conjecture is also true for $\Delta={{7}}$. © 2008 Wiley Periodicals, Inc. J Graph Theory 58:210‐220, 2008
External jugular venous catheterization with a Groshong catheter for central venous access
Authors: Ishizuka Mitsuru , Nagata Hitoshi , Takagi Kazutoshi , Kubota Keiichi 
Published: May 2008

AbstractBackgroundThe Groshong catheter (GC) is commonly used as a peripherally inserted central catheter (PICC), and the external jugular vein (EJV) is not a common route for central venous access (CVA). Therefore, external jugular venous catheterization (EJVC) using a GC is rare. However, our experience has shown that this procedure is safe and simple for CVA.PurposeTo assess the utility of EJVC using the GC for CVA.MethodsCVA was done using a GC via the EJV with a single puncture employing the maximal barrier precaution technique.ResultsBetween March 2005 and June 2007, we attempted to perform EJVC using a GC via the EJV for 331 patients. Among of these patients, 301 patients received successful catheterization (success rate: 301/331 = 90.9%). The total period of catheter insertion was 4601 days, and the mean insertion period was 15.1 days (range 2–147 days). The main complications of catheter insertion were malposition (8/301; 2.7%) and, oozing or hematoma formation (8/301; 2.7%). There were no severe complications such as nerve injury, pneumothorax or arterial bleeding.ConclusionsOur experience demonstrates that EJVC using the GC is acceptable for CVA. J. Surg. Oncol. 2008;98:67–69. © 2008 Wiley‐Liss, Inc.
Effects of Multi‐Arm Structure on Crystallization and Biodegradation of Star‐Shaped Poly(ε‐caprolactone)
Authors: Xie Wenyuan , Jiang Ni , Gan Zhihua 
Published: May 2008

AbstractStar‐shaped PCL with one to five arms were synthesized by ROP. They have the same crystal structure as linear PCL, indicating that the central cores are located in amorphous regions. The influence of arm length and number on crystallization and melting behavior were studied by DSC, POM, and through the Avrami equation. A model is proposed to analyze the enzymatic degradation process of star‐shaped polymers. The multi‐arm structure and the limitation of the central cores on the chain mobility of each arm are considered to be the primary factors influencing the characteristic crystallization and enzymatic degradation behavior of star‐shaped PCLs.magnified image
Elementary constructive theory of Henselian local rings
Authors: Alonso María E. , Lombardi Henri , Perdry Hervé 
Published: May 2008

AbstractWe give an elementary theory of Henselian local rings and construct the Henselisation of a local ring. All our theorems have an algorithmic content. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Strain‐Induced Phase Morphology in Melt Drawn Ultrathin Highly Oriented Block Copolymer Films
Authors: Keller Thomas , Semmler Christian , Jandt Klaus D. 
Published: May 2008

AbstractA strain‐induced microphase morphology has been established by the melt drawing process in a high molecular weight asymmetric polystyrene‐block‐poly(vinyl‐2‐pyridine) (PS‐b‐P2VP) diblock copolymer. For the first time to the best knowledge of the authors, the melt drawing process has been applied to block copolymers to produce free‐standing, ultrathin block copolymer films with a thickness of ≈100 nm. Intriguingly, during the melt drawing of the polymer a global strain‐induced unidirectional order of the microphase separated needle‐like domains of the block copolymer was generated. This morphology consists of a PS matrix with embedded highly oriented P2VP needle‐like domains oriented parallel to the drawing direction. The needle‐like morphology is explained by a simplified extended chain model of the diblock copolymer chains. Annealing of the films leads to a transition from the strain‐induced needle‐like morphology toward the quasi‐equilibrium sphere‐like morphology.magnified image
Degradable Multilayer Films and Hollow Capsules via a ‘Click’ Strategy
Authors: De Geest Bruno G. , Van Camp Wim , Du Prez Filip E. , De Smedt Stefaan C. , Demeester Jo , Hennink Wim E. 
Published: May 2008

AbstractDegradable polymeric multilayer films and microcapsules are fabricated by ‘click’ chemistry using dextran modified with azide and alkyne moieties. Alternating layers of dextran modified with azide and alkyne groups, respectively, are covalently bonded by virtue of the 1,3‐dipolar cycloaddition reaction, known as click chemistry, which leads to the formation of stable triazole cross‐links between the successive layers. The dextran is modified in such a way that the azide and alkyne moieties are connected to the dextran backbone by a hydrolyzable carbonate ester. Therefore, the obtained multilayered structures can be degraded by simple hydrolysis. This type of multilayer avoids the use of polyelectrolytes, which are potentially cytotoxic, and could, therefore, be interesting for the fields of drug delivery and tissue engineering.magnified image
Neural commitment of embryonic stem cells: molecules, pathways and potential for cell therapy
Authors: Suter DM , Krause K‐H 
Published: May 2008

AbstractThe study of neuronal differentiation of embryonic stem cells has raised major interest over recent years. It allows a better understanding of fundamental aspects of neurogenesis and, at the same time, the generation of neurons as tools for various applications ranging from drug testing to cell therapy and regenerative medicine. Since the first report of human embryonic stem (ES) cells derivation, many studies have shown the possibility of directing their differentiation towards neurons. However, there are still many challenges ahead, including gaining a better understanding of the mechanisms involved and developing techniques to allow the generation of homogeneous neuronal and glial subtypes. We review the current state of knowledge of embryonic neurogenesis which has been acquired from animal models and discuss its translation into in vitro strategies of neuronal differentiation of ES cells. We also highlight several aspects of current protocols which need to be optimized to generate high‐quality embryonic stem cell‐derived neuronal precursors suitable for clinical applications. Finally, we discuss the potential of embryonic stem cell‐derived neurons for cell replacement therapy in several central nervous system diseases. Copyright © 2008 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.
Zoledronic acid decreased osteolysis but not bone metastasis in a nude mouse model of canine prostate cancer with mixed bone lesions
Authors: Thudi Nanda K. , Martin Chelsea K. , Nadella Murali V.P. , Fernandez Soledad A. , Werbeck Jillian L. , Pinzone Joseph J. , Rosol Thomas J. 
Published: May 2008

AbstractBACKGROUNDBone metastasis is the most common cause of morbidity and mortality in patients with advanced prostate cancer and is manifested primarily as mixed osteoblastic and osteolytic lesions. However, the mechanisms responsible for bone metastases in prostate cancer are not clearly understood, in part due to the lack of relevant in vivo models that mimic the clinical presentation of the disease in humans. We previously established a nude mouse model with mixed bone metastases using intracardiac injection of canine prostate cancer cells (Ace‐1). In this study, we hypothesized that tumor‐induced osteolysis promoted the incidence of bone metastases and osteoblastic activity.METHODSWe studied the effect of inhibition of osteolysis with zoledronic acid (ZA) on the prevention and progression of Ace‐1 bone metastases in nude mice using prophylactic and delayed treatment protocols. Bioluminescent imaging, radiography, and histopathological evaluation were performed to monitor the effect of ZA on the incidence, progression and nature of bone metastases.RESULTSUnexpectedly, there was no significant difference in tumor burden and the incidence of metastasis between control and treatment groups as detected by bioluminescent imaging and bone histomorphometry. However, radiographic and histopathological analysis showed a significant treatment‐related decrease in osteolysis, but no effect on tumor‐induced trabecular bone thickness in both treatment groups compared to controls.CONCLUSIONOur results demonstrated that the incidence of prostate cancer bone metastases in vivo was not reduced by zoledronic acid even though zoledronic acid inhibited bone resorption and bone loss associated with the mixed osteoblastic/osteolytic bone metastases in the Ace‐1 model. Prostate 68: 1116–1125, 2008. © 2008 Wiley‐Liss, Inc.
A molecular dynamics approach to study the importance of solvent in protein interactions
Authors: Samsonov Sergey , Teyra Joan , Pisabarro M. Teresa 
Published: May 2008

AbstractWater constitutes the cellular environment for biomolecules to interact. Solvent is important for protein folding and stability, and it is also known to actively participate in many catalytic processes in the cell. However, solvent is often ignored in molecular recognition and not taken into account in protein–protein interaction studies and rational design. Previously we developed SCOWLP, a database and its web application (http://www.scowlp.org), to perform studies on the contribution of solvent to protein interface definition in all protein complexes of the PDB. We introduced the concept of wet spots, interfacial residues interacting only through one water molecule, which were shown to considerably enrich protein interface descriptions. Analysis of interfacial solvent in a nonredundant dataset of protein complexes suggested the importance of including interfacial water molecules in protein interaction studies. In this work we use a molecular dynamics approach to gain deeper insights into solvent contribution to protein interfaces. We characterize the dynamic and energetic properties of water‐mediated protein interactions by comparing different interfacial interaction types (direct, dual and wet spot) at residue and solvent level. For this purpose, we perform an analysis of 17 representative complexes from two protein families of different interface nature. Energetically wet spots are quantitatively comparable to other residues in interfaces, and their mobility is shown to be lower than protein surface residues. The residence time of water molecules in wet spots sites is higher than of those on the surface of the protein. In terms of free energy, though wet‐spots‐forming water molecules are very heterogeneous, their contribution to the free energy of complex formation is considerable. We find that water molecules can play an important role in interaction conservation in protein interfaces by allowing sequence variability in the corresponding binding partner, and we discuss the important implications of our observations related to the use of the correlated mutations concept in protein interactions studies. The results obtained in this work help to deepen our understanding of the physico–chemical nature underlying protein–protein interactions and strengthen the idea of using the wet spots concept to qualitatively improve the accuracy of folding, docking and rational design algorithms. Proteins 2008. © 2008 Wiley‐Liss, Inc.
Partial destabilization of native structure by a combination of heat and denaturant facilitates cold denaturation in a hyperthermophile protein
Authors: Chandrayan Sanjeev Kumar , Guptasarma Purnananda 
Published: May 2008

AbstractCold denaturation is a phenomenon seen in many different proteins. However, there have been no reports so far of its occurrence in hyperthermophile proteins. Here, using a recombinant triosephosphate isomerase (PfuTIM) from the hyperthermophile archaeon, Pyrococcus furiosus, we show that the heating of this protein through the low temperature side of its thermal unfolding transition in the presence of guanidinium hydrochloride (GdmCl) results in the formation of partially‐disordered conformational ensembles that retain considerable native‐like secondary and tertiary structure. Unlike PfuTIM itself, these thermochemically obtained partially‐disordered PfuTIM ensembles display cold denaturation as they are cooled to room temperature. The protein thus shows hysteresis, adopting different structural states in a manner dependent upon the nature of the heating and cooling treatment, rather than upon the initial and final conditions of temperature and GdmCl concentration, indicating that some sort of a kinetic effect influences structure adoption and retention. The structure lost through cooling of partially‐disordered PfuTIM is found to be regained through heating. The ability of GdmCl to thus apparently destabilize the highly thermodynamically and kinetically stable structure of PfuTIM (sufficiently, to cause it to display observable cold‐denaturation and heat‐renaturation transitions, in real‐time, with cooling and heating) offers support to current ideas concerning the how hyperthermophile proteins achieve their high kinetic stabilities, and suggests that desolvation‐solvation barriers may be responsible for high kinetic stability. Proteins 2008. © 2008 Wiley‐Liss, Inc.
Magnetocaloric effect and size‐dependent study of the magnetic properties of cobalt ferrite nanoparticles prepared by solvothermal synthesis
Authors: Vázquez‐Vázquez C. , Lovelle M. , Mateo C. , López‐Quintela M. A. , Buján‐Núñez M. C. , Serantes D. , Baldomir D. , Rivas J. 
Published: May 2008

AbstractCobalt ferrite (CoFe2O4) nanoparticles from 2 nm to 15 nm were synthesized using a solvothermal procedure. In this non‐aqueous method, acetophenone was used as solvent and the particle size was controlled by changing the reaction temperature from 120 °C to 180 ºC. Nanoparticles show good crystallinity and uniformity above 140 °C, as determined by X‐ray diffraction and transmission electron microscopy. Magnetic measurements indicate superparamagnetic behaviour. Zero‐field‐cooling (ZFC) dc‐magnetisation experiments at 100 Oe show blocking temperatures ranging from 215 K to more than 305 K. Saturation magnetisation increases with particle size and a small decrease is observed when increasing the temperature. The magnetocaloric effect shown by these cobalt ferrite nanoparticles is reasonably high for nanomaterials. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Low‐dose ion implanted active waveguides in Nd3+ doped near‐stoichiometric lithium niobate: promising candidates for near infrared integrated laser
Authors: Chen Feng , Jaque Daniel , Tan Yang , Yao Shu‐Hua , Liu Hong 
Published: May 2008

AbstractBy applying low‐dose oxygen ion implantation, active planar waveguides in Nd3+ doped near‐stoichiometric lithium niobate laser crystals have been, for the first time to our knowledge, successfully produced. The waveguide exhibits good transmission properties with relatively low propagation loss of ∼2 dB/cm. The confocal micro‐luminescence investigations indicate that the emission properties of Nd3+ ions in the waveguide are well preserved with respect to the bulk, thus showing promising potentials for efficient waveguide laser action operating at the Nd3+ near‐infrared bands. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Data‐driven identification of group dynamics for motion prediction and control
Authors: Schwager Mac , Detweiler Carrick , Vasilescu Iuliu , Anderson Dean M. , Rus Daniela 
Published: May 2008

AbstractA distributed model structure for representing groups of coupled dynamic agents is proposed, and the least‐squares method is used for fitting model parameters based on measured position data. The difference equation model embodies a minimalist approach, incorporating only factors essential to the movement and interaction of physical bodies. The model combines effects from an agent's inertia, interactions between agents, and interactions between each agent and its environment. Global positioning system tracking data were collected in field experiments from a group of 3 cows and a group of 10 cows over the course of several days using custom‐designed, head‐mounted sensor boxes. These data are used with the least‐squares method to fit the model to the cow groups. The modeling technique is shown to capture overall characteristics of the group as well as attributes of individual group members. Applications to livestock management are described, and the potential for surveillance, prediction, and control of various kinds of groups of dynamic agents are suggested. © 2008 Wiley Periodicals, Inc.
Does interfirm modularity complement ignorance? A field study of software outsourcing alliances
Authors: Tiwana Amrit 
Published: May 2008

AbstractKnowledge‐intensive outsourcing alliances present outsourcers with a tension between simultaneously sharing enough private knowledge to accomplish alliance goals and safeguarding such knowledge against misappropriation. This study explores the perspective that increasing interfirm modularity lowers the need for interfirm knowledge sharing. Put another way, modularity complements outsourcee ignorance. Analyses of data on 209 alliances between U.S. firms and software services firms in Russia, Ireland, and India provide strong support for this idea. Our theoretical elaboration and empirical testing of the complementarities between modularity and outsourcee ignorance has significant implications for strategy theory, which are also discussed. Copyright © 2008 John Wiley & Sons, Ltd.
Electron‐Beam‐Induced Deposition in Ultrahigh Vacuum: Lithographic Fabrication of Clean Iron Nanostructures
Authors: Lukasczyk Thomas , Schirmer Michael , Steinrück Hans‐Peter , Marbach Hubertus 
Published: May 2008

AbstractThe generation of nanostructures with arbitrary shapes and well‐defined chemical composition is still a challenge and targets the core of the fast‐growing field of nanotechnology. One approach is the maskless nanofabrication technique of electron‐beam‐induced deposition (EBID). Up to now, the purity of these EBID structures has been rather poor. Here we demonstrate that by performing the EBID process solely under ultrahigh vacuum conditions, the lithographic generation of iron nanostructures on Si(100) with an unprecedented purity of higher than 95% is possible. One particular new aspect is the formation of EBID deposits with reduced size in a strain‐induced diffusive process, resulting in deposits significantly smaller than 10 nm.
Performance of selective space‐time coding and selection diversity under perfect and imperfect CSI
Authors: Pan Ya‐Han , Aïssa Sonia 
Published: May 2008

AbstractSelective space‐time coding and selection diversity can be viewed as practical means to reduce the implementation complexity of multiple‐input multiple‐output (MIMO) systems while still taking benefit of the use of multiple antennas. In this paper, we evaluate the performance of selective space‐time block coding (selective‐STBC) and antenna selection diversity, and analyze the performance of both techniques under perfect and imperfect channel state information (CSI) available at both ends of the transmission link. Our performance analysis reveals that, under perfect or imperfect CSI and ideal feedback channel, selective‐STBC yields a loss in selection diversity gains and that selecting just a single antenna at the transmitter side is the best transmission strategy. We also show that selective‐STBC and antenna selection diversity have different behaviors when the feedback channel is imperfect. Indeed, it is shown that selection diversity outperforms selective‐STBC when the feedback channel is of high quality, while selective‐STBC yields better performance when the feedback channel is of low quality. Copyright © 2008 John Wiley & Sons, Ltd.
Dual silencing of epidermal growth factor and insulin-like growth factor 1 receptors significantly limits growth of nasopharyngeal carcinoma in nude mice
Authors: Zhou X , Yuan Y , Song J , Chen W , Li J , Ye L , Meng X , Xia D 
Published: May 2008

AbstractObjective:We examined the effects of dual silencing of epidermal growth factor and insulin-like growth factor 1 receptors on the growth of nasopharyngeal carcinoma in nude mice; we also assessed potential side effects in these animals.Methods:Short hairpin ribonucleic acid expression vectors targeting epidermal growth factor and insulin-like growth factor 1 receptors were constructed. Short hairpin ribonucleic acid plasmids targeting one or both receptors were transfected into human nasopharyngeal carcinoma cells in nude mice. We then assessed epidermal growth factor receptor and insulin-like growth factor 1 receptor expression and also cellular apoptosis. Peripheral blood was collected and subjected to haematological and biochemical analysis.Results:The findings demonstrated that transfection with dual plasmids (targeting both epidermal growth factor receptor and insulin-like growth factor 1 receptor) resulted in tumour cell growth inhibition of 84.78 per cent, and a significant increase in the number of necrotic and apoptotic cells, compared with single plasmid treatment. The short hairpin ribonucleic acid had no significant side effects on the heart, liver, kidney, spleen or blood system in this experimental model.Conclusion:These results indicate that, in nude mice, dual silencing of both epidermal growth factor and insulin-like growth factor 1 receptors results in more apoptosis and greater nasopharyngeal cancer cell growth inhibition, compared with silencing of either epidermal growth factor receptor alone or insulin-like growth factor 1 receptor alone. This occurred without significant side effects in the experimental animals.
Ways to discharge-based soft X-ray lasers with the wavelength λ<15 nm
Authors: Kolacek K. , Schmidt J. , Prukner V. , Frolov O. , Straus J. 
Published: May 2008

AbstractTwo basic ways to amplification of spontaneous emission in the soft X-ray region are described. The first is based on the electron-collisional recombination pumping scheme, which uses recombination of fully stripped ions into hydrogen-like ions to create (in the case of sufficiently fast cooling) a population inversion on energy levels belonging to the Balmer-alpha transition. We test this scheme on nitrogen, for which the lasing wavelength is 13.4 nm. The second way to amplification of spontaneous emission is based on the electron-collisional excitation pumping scheme: this uses for creation of population inversion a fast excitation of Ne- or Ni-like ions. However, for wavelength below 15 nm it is necessary to use Ni-like ions of some metal vapors. Feeding metal vapors into a capillary is difficult, and if being fed they deposit on the capillary wall and significantly reduce the capillary lifetime. That is why we prepare metal vapor plasma in a capillary with liquid wall – by wire explosion in water. For slowdown of the plasma-channel expansion a local-water-compression by linearly focused shock wave is being developed.