bluuebunny/crossref_metadata_2025_split huggingface dataset:
Effect of water on Bombyx mori regenerated silk fibers and its application in modifying their mechanical properties
Authors: Plaza Gustavo R. , Corsini Paola , Pérez‐Rigueiro José , Marsano Enrico , Guinea Gustavo V. , Elices Manuel 
Published: April 2008

AbstractThe effect of water on regenerated silkworm silk fibers has been studied and compared with that of water on natural silkworm silk fibers. Regenerated fibers are spun from an N‐methylmorpholine‐N‐oxide (NMMO) fibroin solution through a wet‐spinning process, leading to fibers with two distinct tensile behaviors, labeled as brittle and ductile, respectively. Regenerated fibers show a significant contraction when immersed in water. Contraction increases further after drying. In contrast, natural silkworm silk fibers show a negligible contraction when submerged in water. Regenerated fibers tested in water are considerably more compliant than samples tested in air, though their stiffness and tensile strength are significantly reduced. It has been shown that the tensile properties of brittle regenerated fibers can be modified by a wet‐stretching process, which consists of deforming the fiber while immersed in water. Regenerated wet‐stretched fibers always show a ductile behavior independent from their initial tensile behavior. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
Properties of reactive hot melt polyurethane adhesives with acrylic polymer or macromonomer modifications
Authors: Jung Jin Su , Kim Jae Hoon , Kim Min Seok , Jeong Han Mo , Kim Yong Sung , Kim Tae Kyoon , Hwang Jeong Mi , Lee Sang Yun , Cho Yang Lae 
Published: April 2008

AbstractThe properties of reactive hot melt polyurethane adhesives (RHAs) modified by dihydroxyl‐terminated reactive acrylic macromonomers were examined and compared with those of RHAs modified with a nonreactive commercial acrylic copolymer. The melt viscosity and initial bond strength was increased when a portion of the polyols and tackifier was replaced by macromonomers or acrylic copolymers, which have higher glass transition temperatures. When RHA was modified by macromonomer, the storage modulus at low shear rate was reduced and set time was increased, which suggests that the chain entanglement was diminished by short‐chain branches created by the macromonomers. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
Preparation and characterization of fluorescent polymer magnetic particles
Authors: Baharvand H. 
Published: April 2008

AbstractMagnetic iron oxide (maghemite, Fe3O4) particles were encapsulated with fluorescent polymer phase. The resulting fluorescent magnetic polymer particles were characterized by Fourier transform infrared spectroscopy (FTIR), thermal gravimeter analysis (TGA), reflection optical microscopy, differential scanning calorimeter (DSC), Fritsch particle sizer, scanning electron microscopy (SEM), powder X‐ray diffractometer (XRD), and vibrating sample magnetometer (VSM) measurements. FTIR and XRD confirmed the presence of iron oxide in polymer phase. The TGA and DSC measurements indicated that the magnetic polymer particles have more than 50% iron oxide content and high thermal stability. SEM and reflection optical microscopy under UV light revealed that all maghemite particles were embedded in the polymer spheres and have fluorescent characteristics. The size‐distribution analysis of prepared magnetic particles was shown that the means diameter of the particles slightly increased. According to our magnetometry data, shape of the loops evidences the ferromagnetic character of the material and no evidence of superparamagnetism was seen. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
Synthesis of Platensimycin Analogues and Their Antibiotic Potency
Authors: Krauss Jürgen , Knorr Veronika , Manhardt Vera , Scheffels Stefanie , Bracher Franz 
Published: April 2008

AbstractPlatensimycin is a natural product isolated from various strains of Streptomyces platensis which exhibits antimicrobial activity against Gram positive bacteria, including vancomycin‐ and linezolide‐resistant species. Analogues of platensimycin were synthesized from 3‐aminobenzoic acid or other aniline derivatives and several alkyl‐ and aryl‐carboxylic acids. The resulting compounds were tested in an agar diffusion assay against several bacteria and fungi.
Unanticipated Acyloxymethylation of Sumatriptan Indole Nitrogen Atom and its Implications in Prodrug Design
Authors: Rodrigues Tiago , Moreira Rui , Guedes Rita C. , Iley Jim , Lopes Francisca 
Published: April 2008

AbstractSumatriptan is a potent and selective 5‐HT1B and 5‐HT1D agonist used in the symptomatic treatment of migraine; it shows poor oral bioavailability ascribed, in part, to its low lipophilicity. In an attempt to develop acyloxymethyl prodrugs of sumatriptan suitable for oral administration, we carried out the reaction of sumatriptan with chloromethyl esters. To our surprise, acyloxymethylation occurred preferentially at the indole nitrogen rather than at sulfonamide nitrogen, reflecting a difference either in product stability or in the nucleophilicities of the indole and sulfonamide anions. The hydrolysis of the corresponding N1‐acyloxymethyl derivatives was studied in aqueous buffers and in human plasma, by HPLC. N1‐Acyloxymethyl derivatives of sumatriptan are rapidly hydrolysed to the chemically stable N1‐hydroxymethylsumatriptan at pH 1‐13. Slow formation of the parent drug was observed only at high pH values. Hydrolysis of sumatriptan derivatives is slower in human plasma than in phosphate buffer and also generates N1‐hydroxymethylsumatriptan rather than the parent drug. These results indicate that N1‐acyloxymethyl derivatives of sumatriptan cannot be considered as true prodrugs of sumatriptan.
Self‐Assembly of [B‐SbW9O33]9− Subunit with Transition Metal Ions (Mn2+, Cu2+, Co2+) in Aqueous Solution: Syntheses, Structures and Magnetic Properties of Sandwich Type Polyoxometalates with Subvalent SbIII Heteroatom
Authors: Wang Jing‐Ping , Ma Peng‐Tao , Li Jie , Niu Hong‐Yu , Niu Jing‐Yang 
Published: April 2008

AbstractRational self‐assembly of Sb2O3 and Na2WO4, or (NH4)18[NaSb9W21O86] with transition‐metal ions (Mn2+, Cu2+, Co2+), in aqueous solution under controlled conditions yield a series of sandwich type complexes, namely, Na2H2[Mn2.5W1.5(H2O)8(B‐β‐SbW9O33)2]⋅32 H2O (1), Na4H7[Na3(H2O)6Mn3(μ‐OAc)2(B‐α‐SbW9O33)2]⋅20 H2O (OAc=acetate anion) (2), NaH8[Na2Cu4Cl(B‐α‐SbW9O33)2]⋅21 H2O (3), Na8K[Na2K(H2O)2{Co(H2O)}3(B‐α‐SbW9O33)2]⋅ 10 H2O (4), and Na5H[{Co(H2O)2}3W(H2O)2(B‐β‐SbW9O33)2]⋅11.5 H2O (5). These structures are determined by using the X‐ray diffraction technique and further characterized by obtaining IR spectra and performing elemental analysis. Structure analysis reveals that polyoxoanions in 1 and 5 comprise of two [B‐β‐SbW9O33]9− building units, whereas 2, 3, and 4 consist of two isomerous [B‐α‐SbW9O33]9− building blocks, which are all linked by different transition‐metal ions (Mn2+, Cu2+, or Co2+) with different quantitative nuclearity. It should be noted that compound 2 represents the first one‐dimensional sinusoidal chain based on sandwich like tungstoantimonate building blocks through the carboxylate‐bridging ligands. Additionally, 3 is constructed from sandwiched anions [Na2Cu4Cl(B‐α‐SbW9O33)2]9− linked to each other to form an infinitely extended 2D network, whereas 5 shows an interesting 3D framework built up from offset sandwich type polyoxoanion [{Co(H2O)2}3W(H2O)2(B‐β‐SbW9O33)2]6− linked by Co2+ and Na+ ions. EPR studies performed at 110 K and room temperature reveal that the metal cations (Mn2+, Cu2+, Co2+) reside in a square‐pyramidal geometry in 2, 3, and 4. The magnetic behavior of 1–4 suggests the presence of weak antiferromagnetic coupling interactions between magnetic metal centers with the exchange integral J=−0.552 cm−1 in 2.
Synthesis of Novel Monodentate Phosphoramidites and Their Application in Iridium‐Catalyzed Asymmetric Hydrogenations
Authors: Erre Giulia , Junge Kathrin , Enthaler Stephan , Addis Daniele , Michalik Dirk , Spannenberg Anke , Beller Matthias 
Published: April 2008

AbstractNew monodentate H8‐binaphthol based phosphoramidites 6 b–i have been prepared. Starting from (S)‐3,3′‐dibromo‐5,5′,6,6′,7,7′,8,8′‐octahydro‐1,1′‐binaphthyl‐2,2′‐diol 3, a general protocol for the synthesis of ligands 6 is presented. A small ligand library bearing aryl substituents in the 3,3′‐position of the binaphthol core was synthesized and successfully tested in the iridium‐catalyzed asymmetric hydrogenation of 2‐amidocinnamates to obtain different α‐amino acid derivatives in up to 99 % ee.
Kinetically Controlled Ring‐Closing Metathesis: Synthesis of a Potential Scaffold for 12‐Membered Salicylic Macrolides
Authors: Matsuya Yuji , Takayanagi Sho‐ichi , Nemoto Hideo 
Published: April 2008

AbstractFor the synthesis of a 12‐membered salicylic macrolide scaffold, ring‐closing metathesis (RCM) of a ω‐diene compound was planned. The stereochemical outcome of the RCM reaction changed depending on the type of Ru catalyst that was used; a “first‐generation” Grubbs catalyst produced exclusively theEisomer and “second‐generation” catalysts provided a mixture of theEandZisomers under kinetic control (not thermodynamic control). Considerations for theE/Zselectivity are described.
Factors predicting additional disease in the axilla in patients with positive sentinel lymph nodes after neoadjuvant chemotherapy
Authors: Jeruss Jacqueline S. , Newman Lisa A. , Ayers Gregory D. , Cristofanilli Massimo , Broglio Kristine R. , Meric‐Bernstam Funda , Yi Min , Waljee Jennifer F. , Ross Merrick I. , Hunt Kelly K. 
Published: April 2008

AbstractBACKGROUND.The utility of sentinel lymph node (SNL) biopsy (SLNB) as a predictor of axillary lymph node status is similar in patients who receive neoadjuvant chemotherapy and patients who undergo surgery first. The authors of this study hypothesized that patients with positive SLNs after neoadjuvant therapy would have unique clinicopathologic factors that would be predictive of additional positive non‐SLNs distinct from patients who underwent surgery first.METHODS.One hundred four patients were identified who received neoadjuvant chemotherapy, had a positive SLN, and underwent axillary dissection between 1997 and 2005. At the time of presentation, 66 patients had clinically negative lymph nodes by ultrasonography, and 38 patients had positive lymph nodes confirmed by fine‐needle aspiration. Eighteen factors were assessed for their ability to predict positive non‐SLNs using chi‐square and logistic regression analysis with a bootstrapped, backwards elimination procedure. The resulting nomogram was tested by using a patient cohort from another institution.RESULTS.Patients with clinically negative lymph nodes at presentation were less likely than patients with positive lymph nodes to have positive non‐SLNs (47% vs 71%; P = .017). On multivariate analysis, lymphovascular invasion, the method for detecting SLN metastasis, multicentricity, positive axillary lymph nodes at presentation, and pathologic tumor size retained grouped significance with a bootstrap‐adjusted area under the curve (AUC) of 0.762. The resulting nomogram was validated in the external patient cohort (AUC, 0.78).CONCLUSIONS.A significant proportion of patients with positive SLNs after neoadjuvant chemotherapy had no positive non‐SLNs. The use of a nomogram based on 5 predictive variables that were identified in this study may be useful for predicting the risk of positive non‐SLNs in patients who have positive SLNs after chemotherapy. Cancer 2008. © 2008 American Cancer Society.
Completion of adjuvant radiation therapy among women with breast cancer
Authors: Srokowski Tomasz P. , Fang Shenying , Duan Zhigang , Buchholz Thomas A. , Hortobagyi Gabriel N. , Goodwin James S. , Giordano Sharon H. 
Published: April 2008

AbstractBACKGROUND.Optimal treatment for breast cancer often involves lengthy multimodality care including 5 to 6 weeks of radiotherapy, but few studies have evaluated adherence to radiotherapy outside the context of a therapeutic clinical trial.METHODS.Using a SEER‐Medicare database, the authors identified women age 66 years or older with Stage I to III breast cancer diagnosed between 1992 and 2002. They evaluated rates of completion of radiotherapy, defined as a minimum of 25 sessions. Multivariate logistic regression analyses were performed to determine factors associated with completion of radiotherapy, and Cox multivariate models were used to determine the impact of radiotherapy completion on local recurrence.RESULTS.Some 24,510 patients were included in the study. Eighty‐seven percent of patients completed 25 or more radiotherapy sessions. In multivariate logistic regression models, mastectomy (HR 1.26, 95% CI 1.10‐1.43), hospitalization during treatment (2.87, 2.49‐3.31), earlier year of diagnosis, and black race (1.36, 1.14‐1.63) were associated with increased risk of non‐completion of radiotherapy. Among 21,269 patients treated with breast conservation, incomplete radiotherapy was associated with higher risk of local recurrence. A total of 98.7% of patients who did not complete radiation therapy were free of recurrence at 5 years vs. 97.5% of patients who completed radiation therapy (HR 1.46, CI 1.09‐1.95).CONCLUSION.This study demonstrates relatively high rates of completion of radiation therapy among a population of older woman with breast cancer. However, those who did not complete a full course of radiotherapy had small but statistically significant higher risk of breast cancer recurrence. Future efforts should focus on intervening with women at high risk of not receiving adjuvant radiotherapy and increasing rates of radiotherapy completion. Cancer 2008. © 2008 American Cancer Society.
A mixed sensitivity method for structural damage detection
Authors: Yang Q. W. 
Published: April 2008

AbstractStructural damage detection using measured dynamic data has emerged as a new research area in civil, mechanical and aerospace engineering communities in recent years. In this paper, a mixed sensitivity method is presented to identify structural damage by combining the eigenvalue sensitivity with the flexibility sensitivity. The sensitivity of structural flexibility matrix is firstly derived by Neumann series expansion and then the eigenvalue sensitivity together with the flexibility sensitivity are combined to calculate the elemental damage parameters. The presented mixed perturbation approach is demonstrated and compared with the eigenparameter sensitivity method on a 31‐bar truss structure. It has been shown that the proposed procedure is simple to implement and may be useful for structural damage identification. Copyright © 2008 John Wiley & Sons, Ltd.
Comparative study between two numerical methods for oxygen diffusion problem
Authors: Gülkaç Vildan 
Published: April 2008

AbstractTwo approximate numerical solutions of the oxygen diffusion problem are defined using three time‐level of Crank–Nicolson equation and Gauss–Seidel iteration for three time‐level of implicit method.Oxygen diffusion in a sike cell with simultaneous absorption is an important problem and has a wide range of medical applications. The problem is mathematically formulated through two different stages. At the first stage, the stable case having no oxygen transition in the isolated cell is searched, whereas at the second stage the moving boundary problem of oxygen absorbed by the tissues in the cell is searched. The results obtained by three time‐level of implicit method and Gauss–Seidel iteration for three time‐level of implicit method and the results gave a good agreement with the previous methods (J. Inst. Appl. Math. 1972; 10:19–33; 1974; 13:385–398; 1978; 22:467–477). Copyright © 2008 John Wiley & Sons, Ltd.
Equilibrium Kinetics of Chemisorption Processes
Authors: Ledovskikh Alexander , Danilov Dimitry , Notten Peter H. L. 
Published: April 2008

AbstractA new approach to describe the equilibrium kinetics of chemisorption is proposed. The description of the system is based on first‐principles chemical reaction kinetics and statistical thermodynamics. The rate constants are described by using a novel way of activation energy characterization. General expressions for equilibrium gas pressure isotherms and forward/backward reaction rates are obtained as a function of surface coverage. A strong influence of attraction and repulsion interaction energies between the adsorbed species on the equilibrium kinetics is found.
Short‐Range Interactions in Na Coadsorption with CO and O on Ni(111)
Authors: Politano Antonio , Agostino Raffaele G. , Formoso Vincenzo , Chiarello Gennaro 
Published: April 2008

AbstractThe coadsorption of Na with CO and O on Ni(111) is studied by high‐resolution electron energy loss spectroscopy. Experimental evidence for a very short‐range interaction between Na and coadsorbates is reported, in contrast with recent theoretical predictions overestimating nonlocal alkali‐induced effects. Loss spectra show distinct features, as a consequence of different local [CO]:[Na] and [O]:[Na] stoichiometries.
Early postnatal lethality and cardiovascular defects in CXCR7‐deficient mice
Authors: Gerrits Han , van Ingen Schenau Dorette S. , Bakker Nicole E.C. , van Disseldorp Ad J.M. , Strik Ankie , Hermens Laura S. , Koenen Tim B. , Krajnc‐Franken Magda A.M. , Gossen Jan A. 
Published: April 2008

AbstractCXCR7 is a G‐protein coupled receptor that was recently deorphanized and shown to have SDF1 and I‐TAC as high affinity ligands. Here we describe the characterization of CXCR7‐deficient mice that were generated to further investigate the function of this receptor in vivo. Expression analysis using a LacZ reporter knockin revealed that postnatally Cxcr7 was specifically expressed in cardiomyocytes, vascular endothelial cells of the lung and heart, the cerebral cortex and in osteocytes of the bone. Adult tissues revealed high expression in cardiomyocytes and osteocytes. The observation that 70% of the Cxcr7−/− mice died in the first week after birth coincides with expression of Cxcr7 in vascular endothelial cells and in cardiomyocytes. An important role of CXCR7 in the cardiovascular system was further supported by the observation that hearts of the Cxcr7−/− mice were enlarged, showed myocardial degeneration and fibrosis of postnatal origin, and hyperplasia of embryonic origin. Despite high expression in osteocytes no apparent bone phenotype was observed, neither in combination with ovariectomy nor orchidectomy. Thus as CXCR7 does not seem to play an important role in bone our data indicate an important function of CXCR7 in the cardiovascular system during multiple steps of development. genesis 46:235–245, 2008. © 2008 Wiley‐Liss, Inc.
Fluid–structure interaction in lower airways of CT‐based lung geometries
Authors: Wall Wolfgang A. , Rabczuk Timon 
Published: April 2008

AbstractIn this study, the deformability of airway walls is taken into account to study airflow patterns and airway wall stresses in the first generations of lower airways in a real lung geometry. The lung geometry is based on CT scans that are obtained from in vivo experiments on humans. A partitioned fluid–structure interaction (FSI) approach, realized within a parallel in‐house finite element code, is employed. It is designed for the robust and efficient simulation of the interaction of transient incompressible Newtonian flows and (geometrically) non‐linear airway wall behavior. Arbitrary Lagrangian–Eulerian‐based stabilized tetrahedral finite elements are used for the fluid and Lagrangian‐based 7‐parametric mixed/hybrid shell elements are used for the airway walls using unstructured meshes due to the complexity of the geometry. Airflow patterns as well as airway wall stresses in the bronchial tree are studied for a number of different scenarios. Thereby, both models for healthy and diseased lungs are taken into account and both normal breathing and mechanical ventilation scenarios are studied. Copyright © 2008 John Wiley & Sons, Ltd.
Incompressible SPH simulation of water entry of a free‐falling object
Authors: Shao Songdong 
Published: April 2008

AbstractIn this paper an incompressible smoothed particle hydrodynamics (Incom‐SPH) model is used to simulate the interactions between the free surface flow and a moving object. Incom‐SPH method is a two‐step semi‐implicit hydrodynamic formulation of the SPH algorithm and is capable of accurately treating the free surface deformations and impact forces during the solid–fluid interactions. For a free‐falling object, its motion is tracked by an additional Lagrangian algorithm based on Newton's law to couple with the Incom‐SPH program. The developed model is employed to investigate the water entry of a free‐falling wedge. The accuracy of the computations is validated by the good agreement in predicting the relevant hydrokinematic and hydrodynamic parameters. Finally, a numerical test is performed to study the influence of spatial resolution on the water entry features. The Incom‐SPH modeling coupled with the solid–fluid interaction algorithm could provide a promising computational tool to predict the slamming problems in coastal and offshore engineering. Copyright © 2008 John Wiley & Sons, Ltd.
A coupled lattice Boltzmann model for the shallow water‐contamination system
Authors: Li Yineng , Huang Ping 
Published: April 2008

AbstractA coupled numerical method for the direct simulation of shallow water dynamics and pollutant transport is formulated and implemented. The conservation equations of shallow water dynamics equations and the convection–diffusion equations are solved using the lattice Boltzmann (LB) method. The local equilibrium distribution of the pollutant has no terms of second order in flow velocity. And the relaxation time of the pollutant deviates from a constant for the flows with variable free surface water depth. The numerical tests show that this scheme strictly obeys the conservation law of mass and momentum. Excellent agreement is obtained between numerical predictions and analytical solutions in the pure diffusion problem and convection–diffusion problem. Furthermore, the influences on the accuracy of the lattice size and the diffusivity are also studied. The results indicate that the variation in the free surface water depth cannot affect the conservation of the model, and the model has the ability to simulate the complex topography problem. The comparison shows that the LB scheme has the capacity to solve the complex convection–diffusion problem in shallow water. Copyright © 2008 John Wiley & Sons, Ltd.