bluuebunny/crossref_metadata_2025 huggingface dataset:
Analysis of growth rate of silicon nanowires
Authors: Kikkawa J. , Ohno Y. , Takeda S.
Published: April 2011

We have measured the growth rate of silicon nanowires (SiNWs) in the diameter range of 3 to 40 nm (8.4 nm on average), which were grown by chemical vapor deposition (CVD) at temperatures between 365 °C and 495 °C. It is found that SiNWs with smaller diameters grow slower than those with larger ones, and a critical diameter at which growth stops completely exists. The growth rate of the thinner SiNWs stronger depends on growth temperature than that of thicker ones in previous studies. We discuss the dependence by thermodynamics theory.
Precipitation of highly luminescent phases from PECVD Si suboxides
Authors: Perálvarez M. , López M. , Garrido B. , Morante J.R. , Barreto J. , Cadarso V.J. , Riera M. , Zinoviev K. , Dominguez C.
Published: April 2011

Si nanoclusters (Si-nc) embedded in SiO2 present outstanding luminescent emission in the visible and are the material of choice for the realization of efficient light sources integrated with Si technology. PECVD is an attractive preparation route but there is still the need to understand how Si excess and matrix composition affect the precipitation of Si-nc and their photoluminescence (PL) efficiency. The SiOx PECVD layers studied here have a Si excess up to 50% and a thickness between 50 and 100 nm. The phase separation, precipitation and growth of the Si-nc have been achieved by annealing at 1250 °C. For reference, the same study has been performed in Si-nc/SiO2 materials synthesized by ion implantation and annealing. Refractive index and thickness measured by ellipsometry show a densification of the layers after the H release during annealing. A detailed composition profile has been determined by XPS and FTIR analyses and shows almost complete phase separation except for the interfaces, where a depletion of Si-nc is found. EFTEM demonstrates that isolated Si-nc are formed for Si excess up to 25% while for higher Si excess a continuous Si phase is observed. The PL efficiency in PECVD samples is maximized for a Si excess of 17% which is the same Si excess than that for the most emitting implanted samples. No dependence of PL efficiency has been found on the presence of Nitrogen in the matrix (up to the 10%).
The Tribological Behavior of MoS2-Cr Films Sliding Against an Aluminum Counterface
Authors: Krzanowski James E.
Published: April 2011

The tribological performance of MoS2-Cr films in a pin-on-disk test sliding against an aluminum ball has been examined in this study. The MoS2-Cr films were deposited by pulsed laser deposition (MoS2) and simultaneous sputter deposition of Cr, giving a Cr content in the film of 10 mol. %. The results were also compared with films of MoS2 alone. The frictional behavior of MoS2-Cr films was not improved compared to the MoS2 alone, so SEM/EDS studies of the ball and flat were conducted to determine the nature of the transfer films and examine any interface reactions that occurred during the pin-on-disk (POD) test. In the early stages of the POD test (500 cycles) on the MoS2-Cr film, Al-oxide particles formed and caused cratering and scratching of the wear track, and the coefficient of friction neared 0.7. At later stages (9000 cycles), a thick oxide-based transfer film formed on the ball, but on the flat the track composition was closer to that of the original coating. For the films without Cr, after 104 cycles a smooth wear track was observed, and a thin transfer film of MoS2 was found within grooves on the ball wear scar along with Al oxide, which resulted in superior tribological performance.
Investigations of the effect of (Cr1−x, Alx)N coatings’ micro Structure on Impact Toughness
Authors: Bobzin K. , Lugscheider E. , Knotek O. , Maes M.
Published: April 2011

Originated from the tooling industry, PVD (Physical Vapor Deposition) coating development focused on increasing the wear resistance. Nowadays, a steadily increasing market is evolving by coating machine parts. The requirements that have to be met due to the needs of this new market segment focus on tribological behavior. This means, that the focus of wear resistance is shifted towards properties like coefficient of friction, wetting behavior and the response of coatings towards dynamic loads. For many tribological applications, coatings are exposed to severe alternating loads, which are usually left out in common test methods. The approach of common coating test methods are based on the static behavior of deposited coatings. The impact tester is a testing device with a novel approach to dynamic load behavior of both bulk and coated materials. In this paper, the effect of the coatings' microstructure and Young's modulus on the impact toughness was investigated. A change in microstructure was provoked by changing deposition parameters like aluminum content. In a second stage these coatings were then tested with respect to their response to high alternating loads. For this purpose both load and number of impacts were varied.
Control of Stress in Surface Engineered Silicon
Authors: Ma Y. , Job R. , Zölgert B. , Düngen W. , Huang Y. L. , Fahrner W. R.
Published: April 2011

Hydrogen plasma (H-plasma) treatments applied on (100)-oriented standard Czochralski (Cz) silicon wafers cause a structuring of the surface regions in the sub-100 nm scale. The reconstruction of the ‘nano-structured’ surface layers by high temperature vacuum annealing induces strong tensile stress (∼ GPa) at the surface and in the subsurface regions of the wafers, as can be verified by depth resolved μ-Raman spectroscopy (μRS). Although the H-plasma caused ‘nano-structured’ surface layer is very thin (100 – 200 nm), the stressed subsurface regions of the annealed samples are quite extended, i.e. up to ∼ 10 μm depth. The impacts of several process parameters including 1) the doping type of the wafer substrate, 2) the frequency of the H-plasma, 3) the power and duration of the H-plasma, 4) the temperature and duration of the vacuum annealing on the stress are investigated. It is found that the stressed region in the surface engineered silicon wafer can be controlled by the process parameters. The presented results might be important for various applications in semiconductor technology. For example, the H-plasma exposure could be done in local areas near the electrically active regions on the forefront of the wafer. After appropriate annealing, stressed local regions for external getter purposes can be created. Such a method might especially be useful for the formation of getter regions on SOI substrates.
On the Erosion of Material Surfaces caused by Electrical Plasma Discharging
Authors: Soldera Flavio A. , Mücklich Frank
Published: April 2011

The erosion of material surfaces produced by electrical discharges plays an important role on the degradation of many electrical devices, such as electrical contacts, switches or spark plugs. A discharge produces an extreme and concentrated flow of energy into the material that heats it and can even cause melting or vaporization. The plasma pressure may cause an even greater removal of material by the emission of droplets of molten material, producing craters in the surface of the material. In this contribution the microscopic erosion mechanisms on RuAl basis intermetallic compounds are compared with those for pure metals. Single discharge experiments at high pressure were done and the erosion structures were characterized with white light interferometry and scanning electron microscopy. The effects of microstructure on the surface erosion are discussed on the basis of different samples of RuAl. In certain high temperature applications, formation of oxide scales is an important process that may influence the discharge characteristics and erosion mechanisms. These effects are discussed on results in pre-oxidized samples. It was shown, that the surface can be additionally stabilized by controlling the protecting oxide coatings.
Mammalian Cell Interactions with Nanophase Materials
Authors: Bizios Rena
Published: April 2011

Adhesion of differentiated mammalian cells from various hard and soft tissues, including adult mesenchymal stem cells is different on nanophase than on microphase/conventional ceramics (such as alumina, titania and hydroxylapatite) as well as on composites of these ceramics with either poly(L-lactic) acid or poly(methyl) methacrylate. Most importantly, nanophase materials promote selective interactions, for example, of osteoblasts but not of fibroblasts. The type, amount and conformation of adsorbed proteins (such as fibronectin, collagen and vitronectin) are key aspects of the underlying mechanism(s) of subsequent cell interactions with nanophase materials. These cellular/molecular results provide evidence that nanophase biomaterials have the potential for improving the efficacy of implants and for promoting neotissue formation pertinent to tissue engineering, regenerative medicine and other clinical applications.
Ink Jet printing of mammalian primary cells for tissue engineering applications
Authors: Saunders Rachel , Gough Julie , Derby Brian
Published: April 2011

A piezoelectric drop on demand printer has been used to print primary human osteoblast and bovine chondrocyte cells. After deposition the cells were incubated at 37°C and characterised using optical microscopy, SEM and cell viability assays. Cells showed a robust response to printing exhibiting signs of proliferation and spreading. Increasing the drop velocity results in a reduced cell survival and proliferation rates but both cell types grew to confluence after printing under all conditions studied.
Tissue Engineered Bone Using Polycaprolactone Scaffolds Made by Selective Laser Sintering
Authors: Williams J. M. , Adewunmi A. , Schek R. M. , Flanagan C. L. , Krebsbach P. H. , Feinberg S. E. , Hollister S. J. , Das S.
Published: April 2011

Polycaprolactone is a bioresorbable polymer that has potential for tissue engineering of bone and cartilage. In this work, we report on the computational design and freeform fabrication of porous polycaprolactone scaffolds using selective laser sintering, a rapid prototyping technique. The microstructure and mechanical properties of the fabricated scaffolds were assessed and compared to designed porous architectures and computationally predicted properties. Compressive modulus and yield strength were within the lower range of reported properties for human trabecular bone. Finite element analysis showed that mechanical properties of scaffold designs and of fabricated scaffolds can be computationally predicted. Scaffolds were seeded with BMP-7 transduced fibroblasts and implanted subcutaneously in immunocompromised mice. Histological evaluation and micro-computed tomography (μCT) analysis confirmed that bone was generated in vivo. Finally, we have demonstrated the clinical application of this technology by producing a prototype mandibular condyle scaffold based on an actual pig condyle.
New Materials and Methods for Hierarchically Structured Tissue Scaffolds
Authors: Comeau Benita M. , Umar Yusif , Gonsalves Kenneth E. , Henderson Clifford L.
Published: April 2011

The overall goal of our work is to develop new methods and materials for the fabrication of hierarchically structured, three-dimensional (3D) tissue scaffolds. Conventional scaffolds commonly lack substantial mechanical strength, and there is difficulty in controlling porosity, pore distribution, and pore interconnectivity. Additionally, the chemical nature of these scaffolds is typically homogenous. The ability to chemically modify selected areas on a scaffold is one method to direct cell growth in deliberate patterns; which could aid in the engineering of complex, functioning tissues. The general aim of this work is to address these issues through the application of stereolithography (SL) to the fabrication of hierarchically structured scaffolds.

In order to achieve this goal, photopolymerizable materials must be developed that are both compatible with cell growth and with SL processing. SL methods are designed to produce arbitrary control over the physical structure of the part. In addition to physical structure control, control over the local surface chemistry of the scaffold is also desired. This would permit the use of both physical and chemical cues to control cell behavior in a tissue engineering construct. Chemical control could be achieved in SL methods by using photopolymerizable materials that can also be selectively chemically modified during the SL part building process. This paper provides an update on our work directed at using combined photoradical initiated polymerization and photoacid generator based chemical modification of a polymeric scaffold via multi-wavelength SL to produce hierarchically structured scaffolds.
Synthesis and Application of Gold Nanoparticles Functionalized with Collagen Mimetic Peptides
Authors: Mo Xiao , Yu Seungju M.
Published: April 2011

Collagen is the principal tensile element of the extra-cellular matrix in animals and is the basic scaffold for cells and tissues. Abnormalities in its structure are known to result in a number of debilitating human diseases. Collagen mimetic peptides (CMPs) with repeat unit of (Pro-Hyp-Gly) are capable of forming right-handed triple-helical structures similar to that of the collagen triple helices. Recently, our group has shown that CMPs exhibit specific binding affinity to natural collagen under controlled thermal conditions. Using solid phase peptide synthesis, we have prepared a CMP cysteine derivative that was used to modify gold nanoparticles. Transmission electron microscopy (TEM) shows that the Cys-CMP functionalized gold nanoparticles have affinity to collagen fibers. We are investigating the interactions between Cys-CMP functionalized gold nanoparticles and collagen fibers. The Cys-CMP conjugated nanoparticles can potentially be used as a tool to visualize and understand unstable domains of collagen fibers which are related to a number of pathological conditions of extra cellular matrices.
Design and Syntheses of Poly(Norbornenyldecaborane) Precursors to Boron Carbide and Boron-Carbide/Silicon-Carbide Ceramics
Authors: Wei Xiaolan , Welna Daniel T. , Bender Jared D. , Sneddon Larry G. , Allcock Harry R.
Published: April 2011

Poly(norbornenyldecaborane) (PND) was synthesized via ruthenium catalyzed ring opening metathesis polymerization and was found to be a good single-source polymeric boron carbide precursor. Polymer blends of PND and allylhydridopolycarbosilane (AHPCS) were also found to be excellent precursors to boron-carbide/silicon-carbide composite materials.
Hydrolysis of aluminium metal, synthesis of nano alumina and sol-gel processing of monoliths
Authors: Thiruchitrambalam M. , Palkar V.R.
Published: April 2011

High purity alumina is usually prepared using various intermediate aluminium compounds such as aluminium nitrate, aluminium alkoxides etc., as precursors. In fact the above mentioned intermediate aluminium compounds themselves are produced from aluminium metal. The present investigation is concerned with examining the feasibility of using aluminium hydroxides prepared by hydrolyzing aluminium metal, for sol gel processing. The study assumes added significance in view of the claims of Alcoa that it is possible to produce high purity aluminium metal in large quantities economically.

During the present investigation sols were prepared by using various hydroxides, ie., bayerite, gibbsite and boehmite. Sol gel transition was observed only in the case of boehmite sol and this was gelated by either forced gelation method to prepare powder or controlled gelation method to prepare monoliths.

Transparent Xerogels (boehmite) could be prepared by controlled gelation method but the presence of a thin layer of bayerite often resulted in translucency. Crack free monoliths could be prepared by heating the xerogels at a low heating rate(< 1 °C/min). It was found that sol gel processed boehmite transformed to alpha alumina at a relatively lower temperature (∼ 1080 °C ) than the as prepared boehmite which transformed at about 1200 °C.
The thermodynamic stability of three near-degenerate phases of platinum dioxide
Authors: Zhuo Shuping , Sohlberg Karl
Published: April 2011

The thermodynamic stability of the three nearly energy degenerate crystal structures of PtO2 is studied here with first-principles-based calculations of their free energies. For P = 0 the α-(CdI2) structure is the thermodynamically stable phase at low temperature, while the β-(CaCl2) structure is stable at high pressure. The β'-(rutile) structure represents an unstable fixed point on the potential energy surface, or is possibly just barely bound. These results reconcile seemingly contradictory findings and answer longstanding questions about PtO2.
Preparation and Characterization of (C4H9NH3)2MCl4 (M=Mn, Cu)
Authors: Guo Liling , Dai Yadong , Hu Mingjie , Liu Hanxing , Ouyang Shixi
Published: April 2011

With the preparation of organic-inorganic layered perovskite-type compounds (C4H9NH3)2MCl4 (M = Mn, Cu) in solutions, X-ray diffraction (XRD), scanning electron microscopy (SEM), thermal gravimetry (TG) and differential scanning calorimetry (DSC) have been used to characterize the obtained powders. XRD patterns demonstrate that the two compounds have obvious layered structures and SEM pictures reveal that both (C4H9NH3)2MnCl4 and (C4H9NH3)2CuCl4 take on obvious sheet-like microstructure. TG&DSC curves indicate that (C4H9NH3)2CuCl4 decomposes at much lower temperature than (C4H9NH3)2MnCl4.This is ascribed to weakening interactions between its organic and inorganic components, which is presumably due to the Jahn-Teller distortion of [CuCl6] octahedra.
Pure and Ca-doped LaCoO3 Nanopowders: Sol-Gel Synthesis, Characterization and Magnetic Properties
Authors: Armelao Lidia , Barreca Davide , Bottaro Gregorio , Caneschi Andrea , Sangregorio Claudio , Gasparotto Alberto , Gialanella Stefano , Maragno Cinzia , Tondello Eugenio
Published: April 2011

This work is focused on the sol-gel synthesis of pure and Ca-doped LaCoO3 nanopowders. The samples were prepared starting from methanolic solutions of cobalt (II) acetate (Co(CH3COO)2·4H2O), lanthanum (III) nitrate (La(NO3)3·6H2O) and calcium (II) acetate (Ca(CH3COO)2·H2O). After solvent evaporation, the obtained powders were dried under vacuum and subsequently treated in air up to 1273 K. The system evolution under thermal annealing was studied by X-ray Diffraction (XRD) and Transmission Electron Microscopy (TEM), while the chemical composition was analyzed by X-ray Photoelectron (XPS) and X-ray Excited Auger electron (XE-AES) spectroscopies. The temperature and field dependence of the magnetic properties of the Ca-doped samples were investigated, and compared to those of the corresponding pure LaCoO3 powders.
Laser Shot Peening of Inconel 600 and Surface Morphology Characterization
Authors: Bugayev A. A. , Gupta M. C. , Orr J. , Levesque S. , Payne R.
Published: April 2011

The results on laser shot peening and its characterization for Inconel 600 are presented. Using an X-ray diffraction technique we show that the residual compressive stresses can be successfully induced in Inconel 600 with parameters of laser peening, which are close to that of 316L stainless steel. The on-line monitoring system involving the acoustic pulse measurements is described for quality control of laser shot peening process. We found that sample scanning during laser processing results in a system of column-like microstructure, which is tilted in direction of scanning. The features of optical properties of tilted microstructure are described. We revealed that the base material injected into the confining water due to laser ablation is transformed to spherical nanoparticles with diameter of 60nm.
Diagnosis and Modelling of Nonlinear Dynamics in Laser Cutting, Welding and Drilling
Authors: Schulz W.
Published: April 2011

Laser cutting and welding are well established industrial applications. To maintain productivity and to guarantee product quality the industry tries to introduce monitoring and control systems. The long term goal is the autonomous laser machine. Signal assessment is advancing by monitoring and simulation of the dynamical processes. Applying the advanced results about diagnosis and modelling broadens the potentials to cope with productivity and quality features in drilling, trepanning and fine cutting.

As result, in cutting two mechanisms for the formation of adherent dross are revealed theoretically, identified by the monitoring system and can be avoided by modulation of the laser beam power. In welding, the dynamic model predicts the formation of pores sets in or is suspended depending on modulation frequency for the laser power. In drilling the mechanisms governing the maximum depth of the drilled hole – still showing efficient melt removal – are identified experimentally and can be related to the processing parameters theoretically
Thermal and Electric Properties of P(VDF-TrFE) and P(VDF-CTFE) Copolymer Blends
Authors: Li Zhimin , Wang Yuhong , Cheng Z.-Y
Published: April 2011

PVDF-based electroactive polymers (EAP) exhibit high electromechanical performance that is attractive for developing high performance actuators and sensors. In an effort to develop very inexpensive electroactive polymers, P(VDF-TrFE)/P(VDF-CTFE) copolymer blends are studied and reported. The structure, morphology, thermal transition and miscibility of the blend system were investigated by DSC and X-ray diffraction. It is found that the phase transition behavior of the blends can be significantly modified using thermal and mechanical treatmentss. The modified film exhibits high polarization response and low remanent polarization. More importantly, a high electrostrictive strain of 5% was observed in the treated blends. Combined with Young's modulus, the results show that the copolymer blends have a electromechanical coupling factor and energy density comparable or even higher than the irradiated P(VDF-TrFE) copolymers.
Epitaxial Phase Transformation between Cylindrical and Double Gyroid Mesophases
Authors: Zhu Lei , Sun Lu , Miao Jianjun , Cui Li , Ge Qing , Quirk Roderic P. , Xue Chenchen , Cheng Stephen Z. D. , Hsiao Benjamin S. , Avila-Orta Carlos A. , Sics Igors , Cantino Marie E.
Published: April 2011

Complex phase transformation between the hexagonal cylinder (Hex) and double gyroid (G) phases in a polystyrene-block-poly(ethylene oxide) (PS-b-PEO) diblock copolymer was investigated using two-dimensional (2D) synchrotron small-angle X-ray scattering (SAXS), and transmission electron microscope (TEM). The PS-b-PEO sample contained a small population of another bicontinuous cubic phase having an Im3m symmetry. These two bicontinuous cubic phases (G and Im3m) had the same unit cell dimensions. Under a large-amplitude reciprocating shear, the bicontinuous cubic phases transformed into a “single-crystal”-like Hex phase. When annealed at 150 °C for 40 min, the Hex phase partially transformed into well-oriented twinned structures of the G and Im3m phases without significant loss of orientation in 2D SAXS measurements. Epitaxial phase transformation relationships between the Hex/G and Hex/ Im3m phases were identified. The mechanism of the Hex → G transformation was examined by TEM.
Effects of Chain Extension and Branching on the Properties of Poly (Ethylene-Terephthalate)-Organoclay Nanocomposites
Authors: Keyfoglu Ali Emrah , Yilmazer Ulku
Published: April 2011

The effects of chain extension and branching on the properties of nanocomposites produced from recycled poly (ethylene-terephthalate) and organically modified clay were investigated. As the potential chain extension/branching agent, maleic anhydride (MA) and pyromellitic dianhydride (PMDA) were used. The nanocomposites were prepared by twin-screw extrusion, followed by injection molding. Recycled poly (ethylene-terephthalate) was mixed with 2, 3 or 4 weight % of organically modified montmorillonite. During the second extrusion step, 0.5, 0.75 or 1 weight % of MA or PMDA was added to the products of the first extrusion. The effects of the sequence of addition of the ingredients on the final properties of the nanocomposites were also investigated. X-Ray Diffraction analysis showed that, the interlayer spacing of Cloisite 25A expanded from 19.21 Å to about 28–34 Å after processing with polymer indicating an intercalated structure. PMDA content, MA content and screw speed did not have a significant effect on the expanded interlayer distance. In the first extrusion step, nanocomposites containing 3% organoclay content gave significant increase in Young's modulus and decrease in elongation at break values indicating good interfacial adhesion. After the addition of anhydrides, it was observed that, in general PMDA improved the mechanical properties of the nanocomposite owing to the branching and chain extension effects that increase the molecular weight. However, MA did not significantly improve the properties, since in this case the chain scission seemed to be more dominant.
Dynamics of Nanocomposite Formation and Impact Modification of Polyethyleneterephthalate
Authors: Alyamac Elif , Yilmazer Ulku
Published: April 2011

This study was conducted to investigate the effects of component concentrations and addition order of the components, on the final properties of ternary nanocomposites composed of poly(ethylene terephthalate), organoclay, and an ethylene/methyl acrylate/glycidyl methacrylate (E-MA-GMA) terpolymer acting as an impact modifier for PET. Among the investigated addition orders, the best sequence of component addition (PI-C i.e. PET, Impact Modifier-Clay) was the one in which poly (ethylene terephthalate) was first compounded with E-MA-GMA. Later, this mixture was compounded with the organoclay in the subsequent run. In X-ray diffraction analysis, extensive layer separation associated with delamination of the original clay structure was observed in PI-C and (CI-P i.e. Clay, Impact Modifier-PET) sequences with both 1 and 3 wt. % clay contents. X-ray diffraction patterns showed that, at these conditions, exfoliated structures were obtained.
Systemic Trends in Disaster Vulnerability: Migrant and Seasonal Farm Workers in North Carolina
Authors: Montz Burrell E , Allen Thomas R , Monitz Gary I
Published: April 2011

Although researchers from a number of disciplines have long recognized that marginalized groups are at increased risk to the impacts of disasters, it took Hurricane Katrina to bring this to the forefront of policy discussions. An equally insidious problem exists among migrant and seasonal farm workers (MSFWs), yet there is very little work on the nature and range of their vulnerability. In North Carolina, more than ninety per cent of MSFWs are Latino, with the rest being mostly African‐American males. These individuals are particularly vulnerable because of the nature of their work, the poor housing in which they live, and the lack of access to social networks, among other factors. The magnitude of the problem depends on the locations of fields and housing in hazardous areas. Utilizing GIS and Google Earth virtual globe, registered migrant worker camps are mapped using address geocoding with respect to several natural hazards. The results of this work illustrate a compelling need for emergency management to focus on the needs of MSFWs when an event is impending and for policy‐makers to address the factors that put this segment of the population that is so critical to the agricultural economy at such high risk.
Risk Management and Quality Management in Long‐Term Care Organizations: A Collaborative Model
Authors: Guo Kristina L.
Published: April 2011

The U.S. long‐term care system is complex and heavily regulated, yet incidences of risks continue to occur and result in lowered quality of care, and adversely affect patient safety. Risks can be minimized and avoided to safeguard the health and well being of consumers utilizing long‐term care services. The key component to minimizing risks and potential hazards and ensuring high quality in long‐term care facilities is to integrate quality management programs and quality improvement efforts with risk management activities. Currently, risk management and quality management are two distinct functions in long‐term care organizations. Although some activities may be linked, actual coordination and true integration have not taken place. Expansion and integration of risk management and quality improvement functions will result in more effectiveness for both areas. This paper develops a rational model to demonstrate that coordination and integration between risk management and quality management are essential to the delivery of cost effective and quality services in long‐term care organizations.
Phase II/III Study of Intraperitoneal Chemotherapy after Neoadjuvant Chemotherapy for Ovarian Cancer: NCIC CTG OV.21
Authors: Mackay Helen J. , Provencheur D. , Heywood M. , Tu D. , Eisenhauer E.A. , Oza A.M. , Meyer R.
Published: April 2011

Three large randomized clinical trials have shown a survival benefit in women with stage III epithelial ovarian cancer (ECO) who receive intraperitoneal (IP) chemotherapy after optimal primary debulking surgery. The most recent Gynecologic Oncology Group study, GOG 172, showed an improvement in median overall survival of approximately 17 months. That result led to a U.S. National Cancer Institute (NCI) clinical announcement recommending that IP chemotherapy be considered for this group of women with eoc. However, IP chemotherapy is associated with increased toxicity, and rates for completion of treatment are low (42% in GOG 172). The optimal IP regimen and duration of treatment has yet to be defined. Women undergoing chemotherapy before optimal debulking surgery were not included in the studies or in the NCI clinical announcement. The National Cancer Institute of Canada Clinical Trials Group has developed a protocol for a randomized phase II/III study which will examine whether IP platinum–taxane-based chemotherapy benefits women who have received neoadjuvant chemotherapy before optimal surgical debulking. To address whether the less systemically toxic carboplatin can be substituted for cisplatin IP, the first phase of the study will have 3 arms: 1 intravenous-only, and 2 IP-containing regimens. At the end of the first stage, and provided that IP therapy is feasible to administer in this patient population, one of the IP regimens, either IP carboplatin or IP cisplatin, will proceed into a phase III comparison with the intravenous arm. This exciting new study has gathered international support.
Vagal Withdrawal and Sympathetic Overactivity Contribute to the Genesis of Early-Onset Pregnancy-Induced Hypertension
Authors: Pal G. K. , Shyma P. , Habeebullah S. , Pal Pravati , Nanda Nivedita , Shyjus P.
Published: April 2011

Objective. In this study, we have assessed sympathovagal imbalance (SVI) by spectral analysis of heart rate variability (HRV) that contributes to the genesis of early-onset PIH.Methods. Body mass index (BMI), basal heart rate (BHR), blood pressure (BP) and HRV indices such as LFnu, HFnu, LF-HF ratio, mean RR, SDNN and RMSSD were assessed in normal pregnant women (Control group) and pregnant women having risk factors for PIH (Study group) at all the trimesters pregnancy. Retrospectively, those who did not develop PIH (Study group I) were separated from those who developed PIH (Study group II). Study group II was subdivided into early-onset and late-onset PIH. Sympathovagal balance (LF-HF ratio) was correlated with BMI, BHR and BP.Results. LF-HF ratio was significantly high in study group II compared to study group I and control group, and in early-onset PIH group compared to the late-onset category at all the trimesters of pregnancy, which was significantly correlated with BHR and BP. Alteration in HFnu in early-onset category was more prominent than the alteration in LFnu.Conclusion. Though the SVI in PIH is contributed by both sympathetic overactivity and vagal withdrawal, especially in early-onset type, SVI is mainly due to vagal inhibition.
Restricted Radon Transforms and Projections of Planar Sets
Authors: Oberlin Daniel M.
Published: April 2011

We establish a mixed norm estimate for the Radon transform in ℝ2 when the set of directions has fractional dimension. This estimate is used to prove a result about an exceptional set of directions connected with projections of planar sets. That leads to a conjecture analogous to a well-known conjecture of Furstenberg.
Description–experience Gaps: Assessments in Other Choice Paradigms
Authors: Fantino Edmund , Navarro Anton
Published: April 2011

Researchers have become increasingly interested in the description–experience gap or the finding that people respond differently to the same quantitative information depending on whether it is described or experienced. Most studies on the gap have focused on binary choices between a safe option and a risky option and have compared decisions made from description alone versus experience alone. We review studies examining other decision‐related phenomena—probability learning, the sunk‐cost effect, choices in a repeated‐trials prisoner's dilemma, and base‐rate neglect—with an experience‐based approach that often includes conditions combining description and experience. In probability learning, the sunk‐cost effect and a repeated‐trials prisoner's dilemma, participants come closer to behaving optimally when description and experience are simultaneously available than when experience alone is available. In studies of base‐rate neglect, participants respond similarly under conditions of description alone and experience alone. Studies with nonhuman animals strengthen the generality of our conclusions regarding the sunk‐cost effect and suggest a potential cause of base‐rate neglect: a prior experience of having been rewarded for matching like items. Copyright © 2011 John Wiley & Sons, Ltd.
Alkylsulfanylphenyl Derivatives of Cytosine and 7‐Deazaadenine Nucleosides, Nucleotides and Nucleoside Triphosphates: Synthesis, Polymerase Incorporation to DNA and Electrochemical Study
Authors: Macíčková‐Cahová Hana , Pohl Radek , Horáková Petra , Havran Luděk , Špaček Jan , Fojta Miroslav , Hocek Michal
Published: April 2011

Aqueous Suzuki–Miyaura cross‐coupling reactions of halogenated nucleosides, nucleotides and nucleoside triphosphates derived from 5‐iodocytosine and 7‐iodo‐7‐deazaadenine with methyl‐, benzyl‐ and tritylsufanylphenylboronic acids gave the corresponding alkylsulfanylphenyl derivatives of nucleosides and nucleotides. The modified nucleoside triphosphates were incorporated into DNA by primer extension by using Vent(exo‐) polymerase. The electrochemical behaviour of the alkylsulfanylphenyl nucleosides indicated formation of compact layers on the electrode. Modified nucleotides and DNA with incorporated benzyl‐ or tritylsulfanylphenyl moieties produced signals in [Co(NH3)6]3+ ammonium buffer, attributed to the Brdička catalytic response, depending on the negative potential applied. Repeated constant current chronopotentiometric scans in this medium showed increased Brdička catalytic response, which suggests the deprotection of the alkylsulfanyl derivatives to free thiols under the conditions.
Sequential development of diffuse large B‐cell lymphoma in a patient with angioimmunoblastic T‐cell lymphoma
Authors: Huang Jing , Zhang Pei‐Hong , Gao Yu‐Huan , Qiu Lu‐Gui
Published: April 2011

Lymphoma of different histologic type can occur in the same patient. Here, we describe a 64‐year‐old male patient with angioimmunoblastic T‐cell lymphoma (AITL) who subsequently developed diffuse large B‐cell lymphoma (DLBCL). At the time of initial diagnosis, histologic examination of a left inguinal lymph node of the patient and a monoclonal pattern of TCRβ gene rearrangement showed typical features of AITL, and there was no evidence of a monoclonal B‐cell population. Twenty‐six months later, he had generalized lymphadenopathy and organs involvement by DLBCL. A monoclonal IgH gene rearrangement proved de novo development of secondary B‐cell lymphoma and excluded relapse of a primary composite lymphoma. The in situ hybridization analysis showed Epstein‐Barr‐encoded RNA (EBER) sporadic positivity in sample collected from AITL but extensive positivity in the immunoblasts collected from DLBCL. Our observation supports the hypothesis that Epstein‐Barr virus (EBV) is etiologically related to AITL in this case. Clonal expansion of EBV‐associated DLBCL is a secondary event in AITL via EBV infection or reactivation. Diagn. Cytopathol. 2011; © 2011 Wiley‐Liss, Inc.
Combined double CK5/P63 stain: Useful adjunct test for diagnosing pulmonary squamous cell carcinoma
Authors: Fatima Nazneen , Cohen Cynthia , Lawson Diane , Siddiqui Momin T.
Published: April 2011

Increasing demand for accurate differentiation of pulmonary squamous cell carcinoma (SQCC) from other subtypes can be challenging for pathologists. This is more so in fine‐needle aspirations (FNA) since the sample is small and SQCC may show degenerative changes and necrosis that distort the cellular features. Immunohistochemistry (IHC) is a valuable adjunct, and CK5/6 and P63 immunoreactivity is found to be basically restricted to SQCC. In our study, we evaluated the efficiency of CK5/P63 double staining in the diagnosis of pulmonary SQCC in cell blocks (CB) of lung FNA. We used a cohort including 24 CB of lung SQCC and 34 CB of lung adenocarcinomas (ADC). IHC was performed for CK5/P63 double stain. Seventeen of 24 (70%) lung SQCC were positive for the double stain CK5/P63. Two (8%) were positive for CK5 alone and two (8%) were positive for P63 alone. Thus, a total 19 of 24(79%) SQCC of the lung were positive for CK5 and P63 each. In ADC, no immunoreactivity was detected for CK5 alone or combined CK5/P63. Three of 34(8%) ADC were positive for P63. This first study of double staining of CK5/P63 in FNA CB shows a sensitivity of 70% and specificity of 100% for SQCC of the lung. When each marker staining alone is included, the sensitivity for CK5 and P63 increases to 79% each. This double stain can help in the diagnosis of pulmonary SQCC with an accuracy of 88% and a positive predictive value of 100%. Diagn. Cytopathol. 2012. © 2011 Wiley Periodicals, Inc.
Cooperative Catalytic Reactions Using Lewis Acids and Organocatalysts: Enantioselective Propargylic Alkylation of Propargylic Alcohols Bearing an Internal Alkyne with Aldehydes (Eur. J. Org. Chem. 12/2011)
Authors: Motoyama Kazuki , Ikeda Masahiro , Miyake Yoshihiro , Nishibayashi Yoshiaki
Published: April 2011

The cover picture shows that both wings are necessary for a butterfly to fly. Likewise, both a Lewis acid and an organocatalyst contribute cooperatively to the catalytic enantioselective propargylic alkylation of proparglylic alcohols bearing an internal alkyne moiety with aldehydes. Details are discussed in the article by Y. Nishibayashi et al. on p. 2239 ff.
Cyclic and Square‐Wave Voltammetric Signatures of Nitro‐Containing Explosives
Authors: Galik Michal , O'Mahony Aoife M. , Wang Joseph
Published: April 2011

While cathodic voltammetric measurements based on the reduction of nitro‐containing explosive compounds have been well documented, little attention has been given for exploiting their anodic response, associated with the oxidation of their reaction products, for qualitative and quantitative security and forensic information. We demonstrate here that cyclic square‐wave volammetry, combining the cathodic and anodic signals, offers distinct electrochemical profiles for trace nitroaromatic, nitramine and nitrate ester explosives compared to analogous cyclic‐voltammetric and cathodic square‐wave‐voltammetric measurements. Unique electrochemical signatures are also obtained for commonly used explosive mixtures. Such distinct explosive signatures at disposable strip electrodes should facilitate rapid decentralized security screening applications.
Signal peptide mutations in RANK prevent downstream activation of NF-κB
Authors: Crockett Julie C , Mellis David J , Shennan Kathleen IJ , Duthie Angela , Greenhorn John , Wilkinson Debbie I , Ralston Stuart H , Helfrich Miep H , Rogers Michael J
Published: April 2011

Familial expansile osteolysis and related disorders are caused by heterozygous tandem duplication mutations in the signal peptide region of the gene encoding receptor activator of NF-κB (RANK), a receptor critical for osteoclast formation and function. Previous studies have shown that overexpression of these mutant proteins causes constitutive activation of NF-κB signaling in vitro, and it has been assumed that this accounts for the focal osteolytic lesions that are seen in vivo. We show here that constitutive activation of NF-κB occurred in HEK293 cells overexpressing wild-type or mutant RANK but not in stably transfected cell lines expressing low levels of each RANK gene. Importantly, only cells expressing wild-type RANK demonstrated ligand-dependent activation of NF-κB. When overexpressed, mutant RANK did not localize to the plasma membrane but localized to extensive areas of organized smooth endoplasmic reticulum, whereas, as expected, wild-type RANK was detected at the plasma membrane and in the Golgi apparatus. This intracellular accumulation of the mutant proteins is probably the result of lack of signal peptide cleavage because, using two in vitro translation systems, we demonstrate that the mutations in RANK prevent cleavage of the signal peptide. In conclusion, signal peptide mutations lead to accumulation of RANK in the endoplasmic reticulum and prevent direct activation by RANK ligand. These results strongly suggest that the increased osteoclast formation/activity caused by these mutations cannot be explained by studying the homozygous phenotype alone but requires further detailed investigation of the heterozygous expression of the mutant RANK proteins. © 2011 American Society for Bone and Mineral Research
The evolution of a new publication type: Steps and challenges of producing overviews of reviews
Authors: Thomson Denise , Russell Kelly , Becker Lorne , Klassen Terry , Hartling Lisa
Published: April 2011

Background: To date, the Cochrane Child Health Field has published 18 overviews of reviews in our journal, Evidence‐based Child Health: A Cochrane Review Journal. In this article, we highlight some of the logistical and methodological challenges of producing such syntheses. As this is a new and evolving publication type, we hope that our experience will benefit others who engage in this process. Current Methods: We discuss the process we have developed to produce overviews of reviews relevant to our mandate, including identification of the research question, establishment of the author team, selection of outcomes and included SRs, and presentation of findings. Ongoing Development: We discuss the lessons we have learned, outstanding challenges for overview authors, and the limitations of overviews. Conclusions: Overviews of reviews are only as good as the SRs and primary studies on which they are based; gaps or lack of currency in this evidence will weaken the overview of reviews. Future directions in this work must address questions of bias and loss of information. Methods for overviews of reviews targeted for specific groups, such as children, need more elaboration. Copyright © 2011 John Wiley & Sons, Ltd.
Honokiol produces anti‐neoplastic effects on melanoma cells in vitro
Authors: Mannal Patrick W. , Schneider John , Tangada Abhilasha , McDonald Debbie , McFadden David W.
Published: April 2011

Background

Melanoma continues to be a therapeutic challenge for the medical community owing to the scarcity of effective agents available to treat the disease. Honokiol, a traditional Chinese herb, has been proven to have anti‐cancer effects in various cell types, therefore we hypothesized it may have similar cytotoxic capabilities against melanoma cells in vitro.

Methods

Two cell lines, SK‐MEL2 and MeWo, were grown in culture and exposed to increasing doses of Honokiol. Cell proliferation, cytochrome c release into the cytosol, intra‐cellular caspase activity, and mitochondrial depolarization were then evaluated after treatment with honokiol.

Results

Melanoma cells in culture underwent cell death, had increased cytosolic cytochrome c, showed greater caspase activity, and demonstrated increased mitochondrial depolarization after treatment when compared to controls.

Conclusions

It appears that honokiol is an effective inhibitor of cultured human melanoma cells. J. Surg. Oncol. 2011; 104:260–264. © 2011 Wiley‐Liss, Inc.
Mechanical and thermophysical properties of EVA copolymer filled with nickel particles
Authors: Tlili R. , Cecen V. , Krupa I. , Boudenne A. , Ibos L. , Candau Y. , Novák I.
Published: April 2011

Complex physical behavior of ethylene‐vinylacetate (EVA)/nickel composites was investigated in this article. The presence of Ni in EVA matrix leads to an increase of surface hydrophilicity. The peel strength of adhesive joints of EVA/nickel composites to aluminum is sharply increased up to 10 vol% of Ni, followed by a subsequent decrease. The investigated composites are highly elastic and deformable. Young's modulus of composites increases steeply only for concentrations up to 15 vol%. The thermal conductivity of composites significantly increases by the presence of nickel. An interesting correlation between thermal conductivity and relative permittivity of composites was observed. POLYM. COMPOS., 2011. © 2011 Society of Plastics Engineers
An expanded protein–protein interaction network in Bacillus subtilis reveals a group of hubs: Exploration by an integrative approach
Authors: Marchadier Elodie , Carballido‐López Rut , Brinster Sophie , Fabret Céline , Mervelet Peggy , Bessières Philippe , Noirot‐Gros Marie‐Françoise , Fromion Vincent , Noirot Philippe
Published: April 2011

We have generated a protein–protein interaction network in Bacillus subtilis focused on several essential cellular processes such as cell division, cell responses to various stresses, the bacterial cytoskeleton, DNA replication and chromosome maintenance by careful application of the yeast two‐hybrid approach. This network, composed of 793 interactions linking 287 proteins with an average connectivity of five interactions per protein, represents a valuable resource for future functional analyses. A striking feature of the network is a group of highly connected hubs (GoH) linking many different cellular processes. Most of the proteins of the GoH have unknown functions and are associated to the membrane. By the integration of available knowledge, in particular of transcriptome data sets, the GoH was decomposed into subgroups of party hubs corresponding to protein complexes or regulatory pathways expressed under different conditions. At a global level, the GoH might function as a very robust group of date hubs having partially redundant functions to integrate information from the different cellular pathways. Our analyses also provide a rational way to study the highly redundant functions of the GoH by a genetic approach.