bluuebunny/crossref_metadata_2025 huggingface dataset:
Grooves in scratch testing
Authors: Brostow Witold , Chonkaew Wunpen , Rapoport Lev , Soifer Yakov , Verdyan Armen , Soifer Yakov
Published: August 2007

For a number of polymers with a variety of chemical structures and different properties, we have performed scratch-resistance tests and investigated the profiles of the grooves formed using a profilometer. Three main kinds of material response are seen: plowing; cutting; and densification. The cross-sectional areas of the grooves include the groove and side top-ridge areas. The latter are smaller than the former, an indication of densification at the bottom and the sides of the groove; the effect can be connected to molecular dynamics simulations of scratch testing. The sum of the groove and top-ridge areas is the highest for Teflon, thus providing another measure of its poor scratch resistance. The Vickers hardness of the polymers was also determined. An approximate relationship exists between the hardness and the groove area. An unequivocal relationship between the hardness and the total cross-sectional area of the material displaced by the indenter is found. The resulting curve can be represented by an exponential decay function.
A simple route for manufacturing highly dispersed silver nanoparticles
Authors: Andreescu Daniel , Eastman Christopher , Balantrapu Krishna , Goia Dan V.
Published: August 2007

Highly dispersed uniform silver nanoparticles were prepared by reducing silver diamine ions [Ag(NH3)2]+ with D-glucose in the presence of a stabilizing agent. Along with the nature of the dispersing agent, the pH and the temperature of the reaction had the most pronounced effect on the reduction rate, the nucleation of the metallic phase, and ultimately the size and dispersion of the resulting particles. Through suitable manipulations of these parameters, it was possible to prepare uniform Ag nanoparticles ranging in size from 30 to 120 nm. A rapid and complete reduction of the silver species was possible only at elevated pH and temperatures above 50 °C. The reduction of silver diamine ions in these conditions caused the complete cleavage of the C–C bond, resulting in the release of 12 electrons per molecule of D-glucose. It was also found that the addition of ammonia to an already acidified silver nitrate solution leads to the formation of a much more stable and safe-to-handle diamine complex.
Study of Ru barrier failure in the Cu/Ru/Si system
Authors: Damayanti M. , Sritharan T. , Mhaisalkar S.G. , Phoon E. , Chan L.
Published: August 2007

The reaction mechanisms and related microstructures in the Cu/Si, Ru/Si, and Cu/Ru/Si metallization system were studied experimentally. With the help of sheet resistance measurements, x-ray diffraction, field-emission scanning electron microscopy, secondary ion mass spectroscopy, and transmission electron microscopy, the metallization structure with Ru barrier layer was observed to fail completely at temperatures around 700 °C, regardless of the Ru thickness because of the formation of polycrystalline Ru2Si3 followed by Cu3Si protrusions.
Structure and microstructure of near infrared-absorbing Au–Au2S nanoparticles
Authors: Tan Mei Chee , Ying Jackie Y. , Chow Gan Moog
Published: August 2007

Near infrared (NIR) absorbing nanoparticles synthesized by the reduction of HAuCl4 with Na2S exhibited absorption bands at ∼530 nm, and in the NIR region of 650–1100 nm. The NIR optical properties were not found to be related to the earlier proposed Au2S–Au core-shell microstructure in previous studies. From a detailed study of the structure and microstructure of as-synthesized particles in this work, S-containing, Au-rich, multiply-twinned nanoparticles were found to exhibit NIR absorption. They consisted of amorphous AuxS (where x = 2), mostly well mixed within crystalline Au, with a small degree of surface segregation of S. Therefore, NIR absorption was likely due to interfacial effects on particle polarization from the introduction of AuxS into Au particles, and not the dielectric confinement of plasmons associated with a core-shell microstructure.
Cluster spin-glasslike behavior in nanoparticles of diluted magnetic semiconductors ZnS:Mn
Authors: Wang Zhen-Hua , Geng Dian-Yu , Li Da , Zhang Zhi-Dong
Published: August 2007

Zn1−xMnxS nanoparticles with x = 0.08, 0.16, and 0.32 were synthesized by a coprecipitation reaction between nitrate and sodium sulfide at room temperature in air. The magnetic properties of the Zn1−xMnxS nanoparticles were investigated by alternating-current (ac) susceptibility and direct-current (dc) magnetization measurements. The Mn3O4 phase was observed to exist in the Zn1−xMnxS nanoparticles as x ⩾ 0.16. The actual concentrations (x) of Mn-doped ZnS nanoparticles were determined by energy-dispersive x-ray analysis (EDAX) to be 0.06, 0.11, and 0.20, respectively, corresponding to the initial concentrations x = 0.08, 0.16, and 0.32. All the nanoparticles had the cubic structure and the lattice constant of Zn1−xMnxS phase increased with increasing Mn dopant concentration. For the Zn0.68Mn0.32S nanoparticles, there was evidence for appearance of cluster spin-glasslike behavior, as indicated by two maxima around 15 and 25 K in temperature dependence of ac susceptibility. The frequency independence of the peak at higher temperature is related to the intracluster ferromagnetic (FM) interactions, and the frequency dependence of the peak at lower temperature is associated with the spin glass. All the results revealed that the concentration of Mn2+ in Mn–ZnS and the amount of Mn3O4 were crucial for the cluster spin-glass behavior, which was not found when the real concentration (x) was unequal to 0.20 in Zn1−xMnxS.
Preparation and characterization of anatase N–F-codoped TiO2 sol and its photocatalytic degradation for formaldehyde
Authors: Huang Donggen , Liao Shijun , Quan Shuiqing , Liu Lei , He Zongjian , Wan Jinbao , Zhou Wenbin
Published: August 2007

Anatase nitrogen and fluoride codoped TiO2 sol (N–F–TiO2) catalysts were fabricated by a modified sol-gel hydrothermal method, using tetrabutyl titanate as precursor. The microstructure and morphology of sol sample were characterized by x-ray diffraction (XRD), transmission electron microscopy (TEM), ultraviolet-visible dielectric relaxation spectroscopy (UV-VIS-DRS), x-ray photoelectron spectroscopy (XPS), etc. It was shown that N–F–TiO2 particles in sol were partly crystallized to anatase structure and dispersed in the aqueous medium homogeneously. The average particle size was ∼12.0 nm calculated from XRD patterns, and the particle size distribution was narrow. It was noteworthy that the N–F-codoped TiO2 sol particles showed strong visible-light response and high photocatalytic activity for formaldehyde degradation under irradiation by visible light (400–500 nm); we suggested that it may result from the generation of additional band of N 2p in the forbidden band and the synergetic effect of codoping nitrogen and fluorine.
Effect of surface defects on the visible emission from ZnO nanoparticles
Authors: Yadav Harish Kumar , Sreenivas K. , Gupta Vinay , Singh S.P. , Katiyar R.S.
Published: August 2007

The luminescent property of ZnO nanoparticles prepared using the wet chemical method has been investigated. The ZnO nanoparticles in the range 5–10 nm exhibit hexagonal Wurtzite structure, and the photoluminescence (PL) spectrum at room temperature shows a broad visible luminescence band and insignificant near-bandgap emission. The broad green luminescence is dominant at both room and boiled off liquid-nitrogen temperature, while the ultraviolet band edge emission is strongly quenched. The prepared ZnO nanoparticles have residual intermediate compound on the surface in the form of an acetate group, which acts as defect centers for the emission of green luminescence. A trace amount of zinc hydroxide is observed in one of the samples and is found to further enhance the intensity of the green luminescence. Raman scattering studies on nanoparticles indicate that the acetate/hydroxyl groups are loosely bound on the surface and are not present in the interior of the ZnO crystal structure
Low-temperature sintering of PNW–PMN–PZT piezoelectric ceramics
Authors: Lu Pengxian , Zhu Mankang , Xu Dehe , Zou Wenjun , Li Zhengxin , Wang Chunhua
Published: August 2007

For low-temperature firing of Pb0.94Sr0.06(Ni1/2W1/2)0.02(Mn1/3Nb2/3)0.07(Zr0.51Ti0.49)0.91O3(PNW–PMN–PZT) system, BiFeO3is selected as the sintering agent. In this study, the effects of BiFeO3addition and sintering temperature on the microstructures and piezoelectric properties of the ceramics were investigated in detail. The ceramic with 10 mol% BiFeO3sintered at 950 °C possesses optimal microstructure and piezoelectric properties. However, with the increase of sintering temperature the lower relative density, abnormal grain growth, and secondary phase accumulated at grain boundaries are observed, which deteriorates the piezoelectric properties. For the ceramics with different BiFeO3addition sintered at 950 °C, the densification process and the grain growth are improved by suitable BiFeO3, while the morphotropic phase boundary (MPB) moving to the Ti-rich direction and the shrinkage of crystal cell occur. However, extra BiFeO3inhabits the grain growth and introduces more cavities into the materials. Because of the microstructural changes that accompany the addition of BiFeO3and the resulting decrease in sintering temperature, the maximum values of the piezoelectric properties are attained. By doping with 10 mol% BiFeO3, the sintering temperature of the PNW–PMN–PZT system can be lowered successfully from 1200 to 950 °C, while the excellent electric properties are kept.
Improvement in mechanical properties of sintered zirconia (3% yttria stabilized) by glass infiltration
Authors: Balakrishnan A. , Panigrahi B.B. , Chu Min-Cheol , Kim T.N. , Yoon Kyung-Jin , Cho Seong-Jai
Published: August 2007

The goal of this work was to improve the strength of sintered zirconia (3 mol% yttria stabilized) by surface treatment, using a low expansion glass (Mg3Al2Si6O18) at high temperature. The room-temperature strength was increased by about 42% when the glass was penetrated for 30 min. There was a drastic increase in the Weibull modulus. However, the longer holding time led to grain coarsening and the excess glass deteriorated the strength. The magnitude of the strength increment was on the order of surface stress measured experimentally and thermo-elastic stress predicted theoretically. A significant contribution of phase transformation of zirconia from tetragonal to monoclinic phase on the residual stress was also found. Furthermore, compared to the as-sintered zirconia, the glass-treated sample (penetrated for 30 min) exhibited relatively higher strength at elevated temperature (750 °C) and also showed a significant improvement in the thermal shock resistance behavior.
Effect of a minor element with a large mixing enthalpy difference on the plasticity of amorphous alloys
Authors: Kim Kyou-Hyun , Kim Hwi-Jun , Lee Jae-Chul
Published: August 2007

In this study, we investigated the role of a minor alloying element in improving the plasticity of amorphous alloys. The plasticity of the amorphous alloys, Cu60−xZr30Ti10Bex, was drastically improved with increasing amount of Be and reached a maximum of 23% at Cu53Zr30Ti10Be7. It was observed that an atomistic-scale phase separation existed within the alloy, which resulted from the large difference in mixing enthalpy between the binary pairs (Be–Cu, Be–Zr). This atomistic-scale phase separation resulted in an open structure in which atomic rearrangements in the form of the creation of free volume and crystallization were facilitated during deformation. Here we discuss the origin of the enhanced plasticity by clarifying the effect of an additional element, whose mixing enthalpies with the major elements are significantly different, on the structural change of the amorphous alloy.
Electrochemical corrosion study of Sn–XAg–0.5Cu alloys in 3.5% NaCl solution
Authors: Mohanty Udit Surya , Lin Kwang-Lung
Published: August 2007

The electrochemical corrosion behavior of Sn–XAg–0.5Cu alloys in 3.5% NaCl solution was examined using potentiodynamic polarization techniques. The Ag content in the alloy was varied from 1 to 4 wt%. The polarization curves obtained for the alloys show an active–passive transition followed by a transpassive region. Sn–XAg–0.5Cu alloys with higher Ag content (>2 wt%) show a strong tendency toward passivation. The passivation behavior has been ascribed to the presence of both SnO and SnO2on the anode surface. Increase in Ag content from 1 to 4 wt% results in a decrease in the corrosion-current density (Icorr) and linear polarization resistance (LPR) of the alloy. Nevertheless, the corrosion potential (Ecorr) shifts toward negative values, and a decrease in corrosion rate is observed. The presence of Cl−ion initiates pitting and is responsible for the rupture of the passive layer at a certain breakdown potential. The breakdown potential (EBR) decreases and shifts toward more noble values with increase in Ag content in the alloy. Surface analyses by x-ray photoelectron spectroscopy (XPS) and Auger depth profile studies confirmed the formation of both Sn(II) and Sn(IV) oxides in the passive layer.
Contact mechanics for coated spheres that includes the transition from weak to strong adhesion
Authors: Reedy E.D.
Published: August 2007

Recently published results for a rigid spherical indenter contacting a thin, linear elastic coating on a rigid planar substrate have been extended to include the case of two contacting spheres, where each sphere is rigid and coated with a thin, linear elastic material. This is done by using an appropriately chosen effective radius and coating modulus. The earlier work has also been extended to provide analytical results that span the transition between the previously derived Derjaguin–Müller–Toporov (DMT)-like (work of adhesion/coating-modulus ratio is small) and Johnson–Kendall–Roberts (JKR)-like (work of adhesion/coating-modulus ratio is large) limits.
Single-crystal silicon films on glass
Authors: Gadkaree Kishor P. , Soni Kamal , Cheng Shang-Cong , Kosik-Williams Carlo
Published: August 2007

We present a new process based on the electrolysis of glass, which allows the transfer of a single-crystal silicon film while creating an in situ barrier layer free of mobile ions in the glass. This barrier layer consists only of network-forming elements (i.e., aluminum, silicon, and boron) and is free of modifiers. The barrier layer glass is unusual and cannot be synthesized via any of the known glass-forming processes. The barrier layer is thermally stable and thus allows the fabrication of displays with ultimate performance. The process consists of the hydrogen ion implantation of silicon to create a defect structure followed by bringing the glass and the silicon wafer in contact, and finally applying electrical potential to cause the electrolysis of glass.
Comparison of photocatalytic activities of two kinds of lead magnesium niobate for decomposition of organic compounds under visible-light irradiation
Authors: Kako Tetsuya , Ye Jinhua
Published: August 2007

Two new oxide photocatalysts in the Pb–Mg–Nb ternary system, Pb3MgNb2O9 (PMN) and Pb1.83Mg0.29Nb1.71O6.39, have been synthesized, and their photophysical and photocatalytic properties were investigated for the first time. The band gaps of PMN and Pb1.83Mg0.29Nb1.71O6.39 were estimated to be 3.2 and 2.8 eV, respectively, from their absorption spectra. The photocatalytic activity evaluated from the decomposition of 2-propanol into acetone under visible-light irradiation indicated that Pb1.83Mg0.29Nb1.71O6.39 exhibited at least 20 times higher activity than PMN and has a strong oxidizing potential to mineralize organic compounds.
Fracture toughness in direct extruded Mg–Al–Zn alloys
Authors: Somekawa Hidetoshi , Kim Han S. , Singh Alok , Mukai Toshiji
Published: August 2007

Fracture toughness and its deformed structures were investigated on a Mg–3Al–1Zn (AZ31) alloy processed by direct extrusion. The average grain sizes of the alloy after extrusion at temperatures of 473 and 573 K were 4.0 and 14.5 μm, respectively (i.e., fine-grained and coarse-grained alloys). The plane-strain fracture toughness,KIC, as determined by stretched zone analysis in fine-grained and coarse-grained alloys was estimated to be 24.9 and 22.7 MPam1/2, respectively. Microstructural observations of the fine-grained alloy after fracture toughness testing showed that non-basal slip and grain-boundary sliding was activated even at room temperature. In addition, the {10-12} deformation twins were observed despite the fine-grained structures. However, the fraction of deformation twins was reduced with grain refinement, which related to the enhancement of fracture toughness with grain refinement.
Formation process of BaTiO3 particles by reaction between barium hydroxide aqueous solution and titania obtained by hydrolysis of titanium alkoxide
Authors: Zeng Min , Uekawa Naofumi , Kojima Takashi , Kakegawa Kazuyuki
Published: August 2007

BaTiO3 particles were prepared by heating a suspension of titania derived from the hydrolysis of titanium isopropoxide in a barium hydroxide [Ba(OH)2] aqueous solution. Well-crystallized cubic phase BaTiO3 fine particles were obtained by heating at a temperature >328 K for 24 h. The morphology and size of the obtained particles were affected by the reaction temperature and the Ba(OH)2/titanium alkoxide molar ratio. The secondary particles with a larger size were obtained at a lower reaction temperature. The nucleation process of BaTiO3 depended on the reaction temperature. The formation mechanism of BaTiO3 and the formation kinetics were investigated by measuring the concentrations of Ba2+ ions in the solution during the heating process. The BaTiO3 particle formation occurred on the surface of the titania particles after strong adsorption of the Ba2+ ions from the solution. The experimental results showed that the heterogeneous nucleation of BaTiO3 occurred on the titania surface.
Soluble Jagged1 Attenuates Lateral Inhibition, Allowing for the Clonal Expansion of Neural Crest Stem Cells
Authors: Nikopoulos George N. , Duarte Maria , Kubu Chris J. , Bellum Stephen , Friesel Robert , Maciag Thomas , Prudovsky Igor , Verdi Joseph M.
Published: August 2007

The activation of Notch signaling in neural crest stem cells (NCSCs) results in the rapid loss of neurogenic potential and differentiation into glia. We now show that the attenuation of endogenous Notch signaling within expanding NCSC clones by the Notch ligand soluble Jagged1 (sJ1), maintains NCSCs in a clonal self-renewing state in vitro without affecting their sensitivity to instructive differentiation signals observed previously during NCSC self-renewal. sJ1 functions as a competitive inhibitor of Notch signaling to modulate endogenous cell-cell communication to levels sufficient to inhibit neural differentiation but insufficient to instruct gliogenic differentiation. Attenuated Notch signaling promotes the induction and nonclassic release of fibroblast growth factor 1 (FGF1). The functions of sJ1 and FGF1 signaling are complementary, as abrogation of FGF signaling diminishes the ability of sJ1 to promote NCSC expansion, yet the secondary NCSCs maintain the dosage sensitivity of the founder. These results validate and build upon previous studies on the role of Notch signaling in stem cell self-renewal and suggest that the differentiation bias or self-renewal potential of NCSCs is intrinsically linked to the level of endogenous Notch signaling. This should provide a unique opportunity for the expansion of NCSCs ex vivo without altering their differentiation bias for clinical cell replacement or transplant strategies in tissue repair.

Disclosure of potential conflicts of interest is found at the end of this article.
Functional Similarities Among Genes Regulated by Oct4 in Human Mesenchymal and Embryonic Stem Cells
Authors: Greco Steven J. , Liu Katherine , Rameshwar Pranela
Published: August 2007

OCT4 is a master transcriptional regulator, which mediates pluripotency in ESCs through inhibition of tissue-specific and promotion of stem cell-specific genes. Suppression of OCT4, along with other regulators of pluripotency, such as SOX2 and NANOG, has been correlated with cell-fate specification and lineage-specific differentiation. Recent reports have shown the expression of OCT4 in adult MSCs but have not ascribed functional homology with ESCs. MSCs are mesoderm-derived cells, primarily resident in adult bone marrow, that undergo lineage-specific differentiation to generate specialized cells such as stroma, fat, bone, and cartilage. We have previously demonstrated the plasticity of MSCs through their ability to generate neuronal cells. Here, we show that OCT4 provides similar regulatory circuitries in human MSCs and ESCs, using chromatin immunoprecipitation-DNA selection and ligation technology and loss-of-function studies. MSCs were found to express the embryonic transcription factors OCT4, NANOG, and SOX2. In addition, OCT4 was found to (a) target similar genes in MSCs and ESCs, (b) promote the expression of MSC-specific genes, and (c) regulate MSC cell cycle progression. The results suggest similar regulatory mechanisms for OCT4 in MSCs and ESCs and have implications regarding MSC plasticity.

Disclosure of potential conflicts of interest is found at the end of this article.
Irradiation Does Not Compromise or Exacerbate the Innate Immune Response in the Brains of Mice That Were Transplanted with Bone Marrow Stem Cells
Authors: Turrin Nicolas P. , Plante Marie-Michèle , Lessard Martine , Rivest Serge
Published: August 2007

Microglia and invading macrophages play key roles in the brain immune response. The contributions of these two populations of cells in health and diseases have yet to be clearly established. The use of chimeric mice receiving bone marrow-derived stem cell grafts from green fluorescent protein (GFP)-expressing mice has provided an invaluable tool to distinguish between local and blood-derived monocytic populations. The validity of the method is questioned because of the possible immune alterations caused by the irradiation of the recipient mouse. In this experiment, we compared the brain expression of innate immune markers Toll-like receptor 2, interleukin-1β, tumor necrosis factor-α, and monocyte chemoattractant protein-1 in C57BL/6, GFP, and chimeric mice following an intracerebral injection of lipopolysaccharide. The endotoxin caused a marked transcriptional activation of all these innate immune genes in microglial cells across the ipsilateral side of injection. The expression patterns and signal intensity were similar in the brains of the three groups of mice. Consequently, the chimera technique is appropriate to study the role of infiltrating and resident immune cells in the brain without having immune compromised hosts.

Disclosure of potential conflicts of interest is found at the end of this article.
Commentary: Is Totipotency of a Human Cell a Sufficient Reason to Exclude Its Patentability Under the European Law?
Authors: Triller Vrtovec Katja , Vrtovec Bojan
Published: August 2007

This article argues that totipotent character of human totipotent cells—defined as the capacity of a cell “to differentiate into all somatic lineages (ectoderm, mesoderm, endoderm), the germ line and extra-embryonic tissues such as the placenta”—is not a sufficient reason to exclude their patentability on the basis of Article 5(1) of the Directive 98/44/EC on the Legal Protection of Biotechnological Inventions (Biopatent Directive), which maintains that “the human body, at the various stages of its formation and development, […] cannot constitute patentable inventions.” Since human totipotent cells have both the potential to generate an entire new organism or to generate only different tissues or organs of an organism, they simultaneously fit the definition of the unpatentable human body at the earliest stage of its formation as well as of an element of the human body, which “may constitute a patentable invention” pursuant to Article 5(2) of the Biopatent Directive, whether that element is isolated from the human body or otherwise produced by means of a technical process. Therefore, this article suggests that, when evaluating patentability of human totipotent cells, they should be further evaluated according to their location and their method of derivation (i.e., whether human totipotent cells are located in the human body, whether they are isolated from the human body, or whether they are produced otherwise by means of a technical process).

Disclosure of potential conflicts of interest is found at the end of this article.
The Biology Behind mTOR Inhibition in Sarcoma
Authors: Wan Xiaolin , Helman Lee J.
Published: August 2007

Learning Objectives

After completing this course, the reader will be able to: Discuss the function of the mTOR pathway in cancer cell growth and survival.Describe the potential mechanism of targeting this pathway by rapamycin and its derivatives for cancer therapy.Summarize the clinical trials performed with mTOR inhibitors in the treatment of sarcomas and suggest the future clinical development of these inhibitors in the treatment of sarcomas.

CME Access and take the CME test online and receive 1 AMA PRA Category 1 Credit™ at CME.TheOncologist.com
Flat-Fixed Dosing Versus Body Surface Area–Based Dosing of Anticancer Drugs in Adults: Does It Make a Difference?
Authors: Mathijssen Ron H.J. , de Jong Floris A. , Loos Walter J. , van der Bol Jessica M. , Verweij Jaap , Sparreboom Alex
Published: August 2007

Learning Objectives

After completing this course, the reader will be able to: Describe how and why BSA-based dosing was implemented into oncology.Discuss if flat-fixed dosing of adults has advantages over BSA-based dosing in terms of interpatient pharmacokinetic variation of anticancer drugs, efficiency, and costs.Explain which alternative dosing strategies for BSA-based dosing may have potential, leading to a minimum of adverse events and superior therapeutic outcome.

CME Access and take the CME test online and receive 1 AMA PRA Category 1 Credit™ at CME.TheOncologist.com
Profiling Studies in Ovarian Cancer: A Review
Authors: Fehrmann Rudolf S. N. , Li Xiang-yi , van der Zee Ate G. J. , de Jong Steven , te Meerman Gerard J. , de Vries Elisabeth G. E. , Crijns Anne P. G.
Published: August 2007

Learning Objectives

After completing this course, the reader will be able to: Discuss the present status of treating ovarian cancer.Summarize the research in microarray gene profiling.Describe the weakness in microarray gene profile research.Identify the potential applications of gene profiling.

CME Access and take the CME test online and receive 1 AMA PRA Category 1 Credit™ at CME.TheOncologist.com
Clinical Impact of Bortezomib in Frontline Regimens for Patients with Multiple Myeloma
Authors: Manochakian Rami , Miller Kena C. , Chanan-Khan Asher A.
Published: August 2007

Learning Objectives

After completing this course, the reader will be able to: Discuss the efficacy of bortezomib as part of primary therapy for patients with multiple myeloma.Describe the safety of bortezomib and bortezomib-based regimens in patients with previously untreated multiple myeloma.Identify new management options for patients with treatment-naïve multiple myeloma.

CME Access and take the CME test online and receive 1 AMA PRA Category 1 Credit™ at CME.TheOncologist.com
FDA Drug Approval Summary: Pegaspargase (Oncaspar®) for the First-Line Treatment of Children with Acute Lymphoblastic Leukemia (ALL)
Authors: Dinndorf Patricia Anne , Gootenberg Joseph , Cohen Martin H. , Keegan Patricia , Pazdur Richard
Published: August 2007

Learning Objectives

After completing this course, the reader will be able to: Describe the effect of pegylation on asparaginase pharmacokinetics and immunogenicity.Identify the current pegaspargase indications.Discuss the advantages of pegaspargase treatment.Outline the clinical trial design leading to pegaspargase approval by the FDA.List the major adverse events associated with pegaspargase treatment.

CME Access and take the CME test online and receive 1 AMA PRA Category 1 Credit™ at CME.TheOncologist.com
Gemcitabine and Docetaxel in Metastatic Sarcoma: Past, Present, and Future
Authors: Maki Robert G.
Published: August 2007

Objective.

In the era of oral molecular kinase inhibitors, cytotoxic chemotherapy agents are somewhat overlooked, but remain the backbone of treatment for most cancers. Patients with non–gastrointestinal stromal tumor sarcomas, such as leiomyosarcoma, liposarcoma, and undifferentiated high-grade pleomorphic sarcoma (formerly called malignant fibrous histiocytoma), have received doxorubicin and ifosfamide as the backbone of their treatment for over 15 years or more. The goal of this article is to review the data that have led to the use of gemcitabine and docetaxel as a useful combination for patients with metastatic sarcomas, and to comment on possible synergy of the combination.

Methods and results.

The literature regarding the use of gemcitabine, docetaxel, or both, is reviewed, with emphasis on patients with metastatic sarcoma.

Results.

Activity of gemcitabine and docetaxel is observed in leiomyosarcoma and undifferentiated high-grade pleomorphic sarcoma. There is apparent schedule dependence of the combination in other cancers; it is unclear if schedule matters in patients with sarcomas. The dose and schedule of gemcitabine and docetaxel examined in phase II studies are probably too high for routine practice.

Conclusions.

The combination of gemcitabine and docetaxel is an effective option for patients with metastatic sarcoma, increasing the armamentarium for the practicing oncologist in treating this heterogeneous group of diseases. Given the low response rate to docetaxel as a single agent, it is likely that there is true clinical synergy of the combination.
Tests of reinforced concrete short columns laterally strengthened with wire rope units and steel elements
Authors: Yang K.-H. , Ashour A. F.
Published: August 2007

The current paper presents a simple unbonded-type column strengthening technique with wire rope units and few steel elements. Eleven short columns were strengthened using the proposed procedure and tested under monotonic concentric axial loads. The main variables investigated to evaluate the confinement effectiveness of strengthened concrete columns were the volume ratio, prestress, diameter, spacing and configuration of wire rope units. The strength gain factor and ductility ratio increased with the increase of volume ratio of wire ropes. The prestress applied to wire ropes had little influence on the strength gain factor but the ductility ratio decreased with the increase of prestress in the wire ropes, owing to earlier rupture of wire ropes. At the same volume ratio of wire ropes, the maximum strength of columns was nearly independent on the configuration of the wire ropes, but higher ductility was exhibited by columns strengthened with rectangular spiral-type wire ropes than by columns strengthened with hoop-type wire ropes, until rupture of the wire ropes. The strength gain factor and ductility ratio of strengthened columns were compared with those of tied columns tested in a previous study. The load capacity of strengthened columns was also predicted using the ACI 318-05 equation modified to reflect the load-carrying effect of steel elements. A much higher strength gain factor and ductility ratio were exhibited by strengthened columns than tied columns having the same lateral reinforcement, except for strengthened columns with wire rope spacing above 0·5 times core width. The axial load capacity of strengthened columns was higher than that of unstrengthened columns by 5–20%, and could be reasonably predicted using the modified ACI 318-05 equation.
Elastic strain, Young's modulus variation during uniform heating of concrete
Authors: Sabeur H. , Colina H. , Bejjani M.
Published: August 2007

In this work, the variations in elastic strain and Young's modulus of high-performance concrete under constant load and increasing temperatures up to 400°C in accidental conditions are studied experimentally. The same study is carried out under service conditions for high-performance and ordinary concrete subjected to temperatures up to 220°C. The corresponding heating rates are applied until successive constant temperature levels are achieved, and are maintained for several hours to ensure the stabilisation of internal temperature and physico-chemical thermo-dependent processes. The analysis centres on the elastic strain and Young's modulus variations as a function of temperature. The current paper also focusses on the influence of the heating rate. The elastic strain and Young's modulus values are estimated at different temperature levels: 150°C, 200°C, 300°C and 400°C for the high-performance concrete under accidental conditions and 140°C, 190°C and 220°C for both high-performance and ordinary concrete under service conditions.
Influence of section depth on the structural behaviour of reinforced concrete continuous deep beams
Authors: Yang K.-H. , Chung H.-S. , Ashour A. F.
Published: August 2007

Although the depth of reinforced concrete deep beams is much higher than that of slender beams, extensive existing tests on deep beams have focused on simply supported beams with a scaled depth below 600 mm. In the present paper, test results of 12 two-span reinforced concrete deep beams are reported. The main parameters investigated were the beam depth, which is varied from 400 mm to 720 mm, concrete compressive strength and shear span-to-overall depth ratio. All beams had the same longitudinal top and bottom reinforcement and no web reinforcement to assess the effect of changing the beam depth on the shear strength of such beams. All beams tested failed owing to a significant diagonal crack connecting the edges of the load and intermediate support plates. The influence of beam depth on shear strength was more pronounced on continuous deep beams than simple ones and on beams having higher concrete compressive strength. A numerical technique based on the upper bound analysis of the plasticity theory was developed to assess the load capacity of continuous deep beams. The influence of the beam depth was covered by the effectiveness factor of concrete in compression to cater for size effect. Comparisons between the total capacity from the proposed technique and that experimentally measured in the current investigation and elsewhere show good agreement, even though the section depth of beams is varied.
Periodontal Microbiota in Patients With Coronary Artery Disease Measured by Real‐Time Polymerase Chain Reaction: A Case‐Control Study
Authors: Nonnenmacher Claudia , Stelzel Michael , Susin Cristiano , Sattler Alexander M. , Schaefer Juergen R. , Maisch Bernhard , Mutters Reinier , Flores‐de‐Jacoby Lavin
Published: August 2007

Background: Recent data have shown that periodontal disease may increase the risk of occurrence of coronary heart disease in which inflammation initiated by bacteria and their compounds might be a common causal factor. This case‐control study aimed at studying the relationship between periodontal disease and coronary artery disease (CAD) based on clinical and periodontal microbiologic parameters.

Methods: A total of 90 male subjects, 48 to 80 years of age, were included in this study. Forty‐five men had CAD (CAD+), which was confirmed by coronary angiography. Forty‐five age‐matched controls showed no history or symptoms of CAD (CAD−). All subjects underwent a clinical periodontal examination including assessment of tooth loss, probing depth, clinical attachment level, and bleeding on probing. In the CAD+ group, this examination took place 1 day before coronary angiography. Subgingival microbial samples were taken and evaluated by means of real‐time polymerase chain reaction (RT‐PCR) for the total amount of bacteria and the following periodontopathogens: Actinobacillus actinomycetemcomitans, Porphyromonas gingivalis, Prevotella intermedia, Parvimonas micra (formerly Micromonas micros), Dialister pneumosintes, and Campylobacter rectus.

Results: Compared to control subjects, CAD+ subjects had significantly deeper pockets (2.28 mm versus 2.96 mm; P <0.001) and greater attachment loss (2.85 mm versus 3.65 mm; P <0.001), and this difference remained statistically significant after adjusting for smoking. No significant differences were observed between cases and controls with regard to the number of teeth present. P. intermedia was the only periodontal pathogen that showed significantly higher mean counts in CAD+ subjects compared to CAD− subjects. Higher counts of total bacteria, P. micra, D. pneumosintes, and C. rectus were found in the CAD− group.

Conclusion: The results suggest that a relationship between periodontal disease and coronary heart disease exists, although P. intermedia was the only periodontopathogen related to CAD.
Comparison Between Full‐Mouth Scaling and Root Planing and Quadrant‐Wise Basic Therapy of Aggressive Periodontitis: 6‐Month Clinical Results
Authors: Moreira Rafael M. , Feres‐Filho Eduardo J.
Published: August 2007

Background: The aim of this study was to test the hypothesis that there are no differences in clinical parameters in generalized aggressive periodontitis patients after full‐mouth scaling and root planing (FRP) or quadrant‐wise basic periodontal therapy (BPT) when combined with an antibiotic regimen.

Methods: Patients were allocated randomly to BPT (N = 15; mean age: 29.5 ± 5.7 years) or FRP (N = 15; mean age: 28.4 ± 5.7 years). All subjects received oral hygiene instructions including the use of a 0.12% chlorhexidine mouthrinse solution twice a day for 2 months. Patients also received amoxicillin, 500 mg, and metronidazole, 250 mg, three times a day for 7 days. Probing depth (PD), clinical attachment level, visible plaque, and bleeding on probing were recorded at baseline and at 2, 4, and 6 months post‐therapy. Statistically significant changes within and between groups were determined using the general linear model repeated measures procedure.

Results: Both groups showed a significant improvement in all clinical parameters post‐therapy, which was particularly evident at 2 months in the sites that had been deepest at baseline. For instance, the mean PD at sites with mean PD ≥7 mm at baseline had decreased 3.9 mm in the BPT group and 3.6 mm in the FRP group. At 6 months, the percentage of sites with PD ≥7 mm decreased from 13.2% ± 3.2% to 0% in the BPT group and from 13.3% ± 3.5% to 0.2% ± 0.1% in the FRP group. No statistically significant differences were observed between groups for most clinical parameters.

Conclusion: Within the limits of the present investigation, FRP and BPT caused comparable clinical effects in aggressive periodontitis patients when an adjunctive combined antibiotic regimen was included.
Nfic Gene Disruption Inhibits Differentiation of Odontoblasts Responsible for Root Formation and Results in Formation of Short and Abnormal Roots in Mice
Authors: Park Joo‐Cheol , Herr Yeek , Kim Heung‐Joong , Gronostajski Richard M. , Cho Moon‐Il
Published: August 2007

Background: Nuclear factor I genes play an important role in the development of the brain, lung, and roots of teeth. We had reported that Nfic‐deficient mice form normal crowns, but abnormal roots of molar teeth. However, the mechanism by which the disruption of Nfic gene causes abnormal root formation remains unknown.

Methods: To understand this mechanism, the root formation in Nfic‐deficient mice was examined and compared to that of wild‐type mice by morphological, immunohistochemical, and in situ hybridization analyses.

Results: Nfic‐deficient mice formed normal Hertwig's epithelial root sheath (HERS) but severely disrupted odontoblast differentiation, leading to the formation of aberrant odontoblasts in the early stage of root formation. They became dissociated and polygonal in shape, lost their orientation and polarity, and did not express dentin sialophosphoprotein. The abnormal roots contained trapped aberrant odontoblasts, thereby resembling osteodentin in overall morphology. No osteoclasts were associated with abnormal roots. Further, the abnormal roots exhibited a decreased number of cementoblasts and cementum formation on the root surface.

Conclusions: The loss of Nfic did not interfere with the formation of HERS, but it caused disrupted odontoblast differentiation, which resulted in the formation of short and abnormal roots, and decreased cementum. This finding suggests that root dentin is required for normal cementum formation. Therefore, Nfic may be a key regulator of root odontoblast differentiation and root formation.
Periodontitis Associated With Hajdu‐Cheney Syndrome
Authors: Bazopoulou‐Kyrkanidou Euterpe , Vrahopoulos Theofilos P. , Eliades George , Vastardis Heleni , Tosios Konstantinos , Vrotsos Ioannis A.
Published: August 2007

Background: Hajdu‐Cheney syndrome (HCS) is an inheritable, rare disorder of bone metabolism, associated with acro‐osteolysis of the distal phalanges, short stature, distinctive craniofacial and skull changes, premature tooth loss, and periodontitis. This report focuses on the periodontal manifestations of HCS.

Methods: A 22‐year‐old female presented with the characteristic clinical features of HCS, including short stature, small face, prominent epicanthal folds, thin lips, small mouth, and short hands. There were no abnormal biochemical, hematological, or hormonal data. Tests for bone mineral density were indicative of osteoporosis. Cephalometric analysis revealed hypoplasia of the midface and increased cranial base angle; the maxilla and the mandible were set posteriorly. The sella turcica was enlarged, elongated, and wide open with slender clinoids. Hair samples were examined by scanning electron microscopy, and tooth cementum and dentin were evaluated histologically.

Results: According to the periodontal evaluation, gingival inflammation was 12.5%, bleeding on probing score was 24%, probing depths averaged 4 to 6 mm, and clinical attachment loss averaged 3 to 6 mm. Class II furcations were found on three teeth. Almost all teeth exhibited pathological mobility of varying degrees. There was a generalized, horizontal bone loss of ∼50%. Three teeth had to be extracted because of severe localized periodontal destruction. Histologic examination of the dentin and the cementum was normal.

Conclusions: HCS periodontitis is associated with an unpredictable and uneven, rapid rate of periodontal destruction of unknown etiology. Further research is required to identify the role of the possible pathogenic factors involved.
Increasing the Apico‐Coronal Dimension of Attached Gingiva Using the Modified Apically Repositioned Flap Technique: A Case Series With a 6‐Month Follow‐Up
Authors: Carnio João , Camargo Paulo M. , Passanezi Euloir
Published: August 2007

Background: This case series reports on the effectiveness of the modified apically repositioned flap (MARF) in increasing the apico‐coronal dimension of attached gingiva over multiple adjacent teeth.

Methods: The MARF surgical technique consists of a single horizontal incision within keratinized tissue, elevation of a split‐thickness flap, and suturing of the flap to the periosteum in an apical position. The periosteum is left exposed so that the full perimeter of the wound is surrounded by keratinized tissue. The nature of this wound healing leads to the formation of new keratinized and attached tissue in the area where periosteum is left exposed. A total of 37 areas in 33 systemically healthy patients were analyzed after treatment with the MARF technique. The treatment areas consisted of a minimum of two and a maximum of five adjacent teeth with a minimum of 0.5 mm and a maximum of 2.0 mm of attached gingiva on each tooth.

Results: Treatment with MARF resulted in a significant increase in the apico‐coronal dimension of the keratinized tissue and attached gingiva (P <0.05). The increase in keratinized tissue ranged from 2.20 to 4.28 mm, and the increase in attached gingiva ranged from 1.0 to 3.14 mm. Gingival recession decreased significantly in the treated areas, but the difference was of little clinical significance. Probing depths in the treated areas did not change significantly compared to baseline values.

Conclusions: MARF is an effective technique in increasing the apico‐coronal dimension of the keratinized tissue and attached gingiva. MARF offers considerable advantages over other mucogingival surgery techniques: simplicity, limited chair time for the patient and the operator, low morbidity because of the absence of palatal donor tissue, and a predictable tissue color match.
Lutheran Blood Group Antigen as a Receptor for α5 Laminins in Gingival Epithelia
Authors: Willberg Jaana , Hormia Marketta , Takkunen Minna , Kikkawa Yamato , Sekiguchi Kiyotoshi , Virtanen Ismo
Published: August 2007

Background: Lutheran blood group glycoprotein (Lu) is a transmembrane receptor of the immunoglobulin superfamily. Lu serves as a receptor for α5 laminins (Lm). The Lm α5 chain is a constituent of Lms‐511 and ‐521. Lm‐511 is found in most human basement membranes (BMs) and also is detected in BM of gingival epithelia. Recent studies indicated that Lu mediates cell adhesion to Lms‐511/521 independently or in concert with integrins. This study focused on the expression of Lu in gingival epithelia and on cultured immortalized gingival keratinocytes. The role of Lu and α3 and β1 integrin subunits in the adhesion of oral epithelial cells to Lms‐511/521 was also studied.

Methods: Immunofluorescence microscopy was used to study the expression of Lu in gingival tissues and in cultured gingival keratinocytes. Immunoprecipitation of radioactively metabolically labeled cells was used to detect Lu. Cell adhesion to Lm‐511/521 preparation and to pure Lm‐511 was studied in quantitative cell adhesion experiments. Morphological adhesion assays were carried out for visualization of the morphology and adhesion structure formation of the adhering cells.

Results: Immunofluorescence studies on gingiva showed complete coalignment of Lu on basal epithelial cells with the BM Lm α5 chain. A surface‐confined, punctate immunoreaction for Lu was detected throughout cell surfaces on cultured gingival cells. Immunoprecipitation showed a broad polypeptide with molecular weight 85,000. In quantitative cell adhesion assays, the adhesion of cells to both Lm α5 preparations was diminished with monoclonal antibodies (MAbs) against integrin α3 and even more effectively with MAbs against the β1 subunit. When the adhesion sites were blocked with soluble recombinant Lu (sol‐Lu), the adhesion of gingival epithelial cells to Lms‐511/521 was reduced significantly, and sol‐Lu increased the inhibition with integrin α3 antibody. Lm‐511 did not induce lamellipodia or focal contacts in cultured gingival keratinocytes.

Conclusions: Lu was in coalignment with Lm α5 chain in gingival epithelia. Lu also seemed to have a role in gingival epithelial cell adhesion together with integrin α3β1.