bluuebunny/crossref_metadata_2025 huggingface dataset:
High-k Gate Dielectric MOSFETs: Meeting the Challenges of Characterization and Modeling
Authors: De Souza Maria M. , Sicre Sebastien , Casterman Damien
Published: April 2011

Although high-k/metal gate MOSFETs have made it into manufacturing at the 45 nm CMOS technology node there still remain many challenges associated with their implementation under debate ranging from unknowns in stack parameters to frequency dispersion during measurement. We elucidate methodologies to address frequency dispersion in depletion and inversion via the conductance technique using typical test case of a poly/TiN and polysilicon gate. Analytic expressions for the extraction of transistor parameters are compared with those from Schrodinger-Poisson simulations. The poly/TiN gate has a significantly reduced EOT and a similar mobility to the polygate. Using insight from Quantum Mechanical calculations, it is demonstrated that the quantity and location of fixed oxide charge plays a decisive role in the mobility degradation.
Resistive Switching Behaviors of ReRAM Having W/CeO2/Si/TiN Structures
Authors: Dou Chunmeng , Mukai Koki , Kakushima Kuniyuki , Ahmet Parhat , Tsutsui Kazuo , Nishiyama Akira , Sugii Nobuyuki , Natori Kenji , Hattori Takeo , Iwai Hiroshi
Published: April 2011

As one of emerging next-generation nonvolatile memories, Resistive RAM (ReRAM) still calls new material technology to improve its performance. By utilizing the special characteristics of cerium oxides, this paper proposes a new method to improve the performance of CeO2 based ReRAM devices by using Si buffer layer. It is confirmed that the device having W/CeO2/Si/TiN structure shows significant advantage over the device without Si layer for memory application in terms of lower forming voltage, smaller compliance current, larger window and better endurance characteristic. The effect of Si buffer layer is discussed in detail and a model based on filament switching mechanism was also proposed to explain the underlying reasons.
Electrically Detected Magnetic Resonance in Dielectric Semiconductor Systems of Current Interest
Authors: Lenahan Patrick M. , Cochrane C.J. , Campbell J.P. , Ryan J.T
Published: April 2011

Several electrically detected magnetic resonance techniques provide insight into the physical and chemical structure of technologically significant deep level defects in solid state electronics. Spin dependent recombination is sensitive to deep level defects within semiconductors or at semiconductor dielectric interfaces. Spin dependent trap assisted tunneling can identify defects in dielectric films and , under some circumstances, can provide fairly precise information relating energy levels to physical/ structural information about the defects under observation.
Synthesis, Pore Morphology, and Dielectric Property of Mesoporous Low-k Material PSMSQ Using a Reactive High-Temperature Porogen, TEPSS
Authors: Chiu Shih-Ya , Hsu Hsin-Ling , Che Mu-Lung , Leu Jihperng
Published: April 2011

A high-temperature reactive porogen, triethoxy(polystyrene)silane (TEPSS) (Mw=3,500 g/mole), suitable for late-porogen removal integration scheme has been synthesized in p-xylene via atom transfer radical polymerization. TEPSS was then grafted onto poly(methyl-silsesquioxane) (MSQ) matrix (k=2.9) to circumvent possible phase separation between matrix and porogen in the hybrid approach and porogen aggregation. Our results shows porous low-k MSQ films possess uniform pore size, 24 nm for porosity up to 40%, primarily due to low PDI and reactive porogen, and the dielectric constant is decreased to 2.37 at 40% porosity. In addition, less porogen aggregation was observed at porogen loading ~40 v%.
Study of Porous SiOCH Patterning Using Metallic Hard Mask: Challenges and Solutions
Authors: Posseme Nicolas , David Thibaut , Chevolleau Thierry , Darnon Maxime , Bailly Fanny , Bouyssou Regis , Ducote Julien , Chaabouni Hamed , El Kodadi Mohamed , Licitra Christophe , Verove Christophe , Joubert Olivier
Published: April 2011

The choice of copper/low-k interconnect architectures is instrumental in achieving high device performances. Today, the implementation of porous low-k materials becomes mandatory in order to compensate metal resistance increase upon RC product. However, their introduction, which was initially planned for the 65nm technological node, was delayed to 45nm node due to integration issues. Using an integration strategy which combines porous SiOCH materials and metal hard masks, the difficulties and possible solutions are presented in this paper with emphasis on plasma etching.
Ultra Low Dielectric Constant Materials for 22 nm Technology Node and Beyond
Authors: Baklanov Mikhail R. , Smirnov Evgeny A. , Zhao Larry
Published: April 2011

Metrology and approaches necessary for selection of ultra low-k dielectric materials for future generation of IC devices are discussed. It is shown that porogen residue (sp2 hybridized carbon) formed during the UV curing of porogen based PECVD low-k materials increases the leakage current density and decreases the breakdown field. The amount of porogen residue increases with porosity because of larger amount of co-deposited porogen. Electrical characteristics of these films are significantly worse in comparison with low-k films prepared by using of self-assembling approaches without porogen. Therefore, utilization of porogen based technologies for preparation of ultra low-k films is limited. New metrologies allowing evaluation of intrinsic properties of low-k materials are discussed. It is shown that UV spectroscopy and a unique planar capacitor test vehicle are extremely important for evaluation of intrinsic properties of ultra low-k films.
Development of Porosimetry Techniques for the Characterization of Plasma-Treated Porous Ultra Low-k Materials
Authors: Licitra Christophe , Chevolleau Thierry , Bouyssou Regis , El Kodadi Mohamed , Haberfehlner Georg , Hazart Jerome , Virot Leopold , Besacier Maxime , Posseme Nicolas , Darnon Maxime , Hurand Romain , Schiavone Patrick , Bertin Francois
Published: April 2011

For the sub-32 nm node, porous SiCOH dielectrics (p-SiCOH) are integrated using dual damascene patterning by etching trenches and vias into the porous material. One challenge is to control the process conditions to minimize the plasma-induced damage of p-SiCOH materials at the bottom and at the sidewall of the trenches. Ellipsometric Porosimetry has been adapted to characterize the plasma-treated materials for both horizontal and vertical surfaces. Since surface modifications can cause adsorption and desorption delays and hydrophobicity loss, porosimetry measurements operated with multi-solvent and kinetic protocols are required. Quantitative measurements of vertically patterned materials are demonstrated using periodic structures of porous material and a Scatterometric Porosimetry analysis. Results show a good sensitivity of the measurement to the different process conditions but also highlight a different impact of the plasma processes on patterned materials compared with blanket films.
Development of Voltammetry-Based Techniques for Characterization of Porous Low-k/Cu Interconnect Integration Reliability
Authors: Kim Choong-Un , Chen LiangShan , Michael Nancy , Bang Woong Ho , Park Young-Joon , Ryan Todd E. , King Sean
Published: April 2011

This paper concerns the new method of detecting the integration failures in porous low-k (PLK)/Cu interconnects using simple voltammetry-based techniques. In essence, the technique takes advantage of the fact that pores in PLK allow permeation of liquid, including electrolyte, into interconnect structures. The infiltration of electrolyte allows the formation of a micro-cell, consisting of two mating Cu interconnect electrodes and the electrolyte in PLK, where simple linear voltammetry can examine various integration reliability issues pertinent to PLK/Cu interconnects. Specifically, the technique is proven to be effective in detection of 1) failure in Ta barrier, 2) cracks in the capping layer, and 3) trapped impurity in pores in PLK. The working principle of the voltammetry technique and demonstration of its effectiveness is introduced in this paper.
Flatband Voltage Tuning of HfSiON-Based Gate Stacks: Impact of High Temperature Activation Annealing and LaOx Capping Layers
Authors: Boujamaa Rachid , Baudot Sylvain , Martinez Eugénie , Renault Olivier , Detlefs Blanka , Zegenhagen Jorg , Loup Virginie , Martin François , Gros-Jean Mickael , Bertin Francois , Dubourdieu Catherine
Published: April 2011

We have investigated high temperature annealing effects on the flatband voltage (Vfb) modulation of TiN/LaOx/HfSiON/SiON/Si gate stacks with different LaOx thicknesses. Using hard X-ray photoelectron spectroscopy with synchrotron radiation and capacitance versus voltage measurements, we show band alignments shifts of the gate stacks attributed to La diffusion into the bottom HfSiON/SiON interface and the subsequent creation of an interfacial dipole. From electrical measurements on beveled oxide capacitors, we demonstrate that the effective work function of the metal can be increased to the desired value for transistor operation, which is a key point for optimizing these advanced devices.
Interface Structure and Charge Trapping in Hf-Incorporated Y2O3 Gate Dielectrics on Germanium
Authors: Mahata Chandreswar , Mallik S. , Das T. , Hota M.K. , Maiti C.K.
Published: April 2011

Y2O3 and HfYOx (~12nm) high dielectric constant films, with RF sputtering, have been prepared and studied with respect to their chemical bonding and electrical properties. The rapid thermal annealing after high-k dielectric deposition in N2 ambient showed major impacts on crystalinity properties. The incorporation of Hf into Y2O3 causes reduction in generation of positive oxide charge and leakage current density. The mechanism of leakage current reduction is considered to be due to Hf-induced compensation of existing oxygen vacancies. Moreover, HfYOx films exhibit superior electrical performances in terms of charge trapping induced flatband voltage instability and gate leakage current compared to directly deposited Y2O3 high-k dielectric films on Germanium. The density of interface traps (Dit) and border traps (Nbt) estimated from high-frequency CV curves (1 MHz) indicates that incorporation of Hafnium can improve the interfacial defects.The breakdown field in MIS capacitor with Y2O3 gate dielectric was significantly enhanced by incorporating Hf.
Schottky Barrier Height at Dielectric Barrier/Cu Interface in Low-K/Cu Interconnects
Authors: King Sean , French Marc , Jaehnig Milt , Kuhn Markus , French Benjamin
Published: April 2011

In order to understand the various possible leakage mechanisms in low-k/Cu interconnects, a knowledge of the basic band alignment between Cu and low-k dielectric materials is needed but has gone largely unreported. In this regard, we have utilized X-ray Photoelectron Spectroscopy (XPS) to measure the Schottky Barrier at interfaces of importance to Cu/low-k interconnects. Specifically, we have utilized XPS to determine the Schottky Barrier at the interface between Cu and low-k SiCN capping layers deposited on Cu via Plasma Enhanced Chemical Vapor Deposition (PECVD). We have also utilized XPS to investigate the impact of various plasma surface treatments on the band alignment at these interfaces. The cumulative results indicate that electron transport along the SiCN:H/SiOC:H interface may represent the lowest energy barrier path for line-line Schottky emission based leakage.
Degradation Mechanisms of MILC P-Channel Poly-Si TFTs under Dynamic Hot-Carrier Stress Using a Novel Test Structure
Authors: Lin Cheng-I , Hong Wen-Chiang , Lin Tin-Fu , Lin Horng-Chih , Huang Tiao-Yuan
Published: April 2011

In this study, dynamic hot carrier effect in the MILC p-channel TFT device can be characterized by the unique struture. This novel structure is capable of spatially resolving the hot carrier effect and is highly sensitive to detect the defect-rich region. The dynamic hot carrier stress is focused on the impacts of the frequency, the rising time and the falling time. In varied frequency stress condition, the degradation in the DMT increases monotonically with increasing frequency, infering that more defects are generated by extra dynamic stress contribution in the drain side and degrade the characteristic of device. Under varied falling time stress condition, the on-current degradtion become severe with decreasing falling time due to the extra voltage drop during voltage switch, The final part is effect of rising time, whose degradation is resulted from the the large voltage drop exists between the channel and the junction while device switches.
Solution Processed High-k Lanthanide Oxides for Low Voltage Driven Transparent Oxide Semiconductor Thin Film Transistors
Authors: Choi Sungho , Park Byung-Yoon , Jang Mi , Jeong Sunho , Lee Ji-Yoon , Ryu Beyong-Hwan , Seong Tae-Yeon , Jung Ha-Kyun
Published: April 2011

ZnO-based low power operating thin film transistors (TFTs) were fabricated by a simple and robust solution process. Combined the amorphous oxide semiconductors with the high capacitance lanthanide oxides thin film, Y2O3 and Gd2O3, as a gate insulator, the resultant device exhibits an enhanced device performance; lower threshold voltage, increased carrier mobility, and smaller subthreshold slope with exceptionally low operating voltage than the typical TFT devices using a SiO2 gate insulator.
A MIM Diode with Ultra Abrupt Switching Process and High On/Off Current Ratio
Authors: Zhang Lijie , Huang Ru
Published: April 2011

In this work, a TaOx-based Metal-Insulator-Metal (MIM) diode is demonstrated. This Cu/TaOx/W diode is fabricated with sputtering method without any high temperature process (~ 400oC), which shows promising compatabiltiy with CMOS back-end process. The fabricated diode exhibits abrupt switching process (~3mV/dec) with small switching voltage (~ 0.7V), high on/off current ratio more than 106, low leakage current (~ pA). Current is limited when the diode is switched to the on-state to avoid the hard breakdown caused by the thermal run-away. On/off current ratio can be further improved to 108 by the limited current increase at the precondition of ensuring the safty of the diode. This MIM diode can be easily integrated into high density PCM or RRAM cross-point arrays due to its simple fabrication process. Its nearly ideal diode behavior with ultra low on-resistance can also be used as an ESD protection device or as a rectifying element in circuit.
Radical (HO•, H• and HOO•) Formation and Ionomer Degradation in Polymer Electrolyte Fuel Cells
Authors: Gubler Lorenz , Dockheer Sindy M. , Koppenol Willem H.
Published: April 2011

Formation of radicals, such as HO•, H• and HOO•, in the membrane of the polymer electrolyte fuel cell and their attack on perfluoroalkylsulfonic acid (PFSA) and poly(styrenesulfonic acid) (PSSA) ionomers was simulated based on a kinetic framework with H2O2 as “parent” molecule and with contaminating Fe as parameter. Analysis under quasi-steady state conditions yielded radical concentrations of around 10−19 M for H•, 10−16 M for HO• and 10−10 M for HOO•. H• is formed via the reaction of HO• with H2 dissolved in the membrane. The attack of the PFSA ionomer was assumed to proceed via weak carboxylic end-groups. The corresponding calculated fluoride emission rate (FER) showed good agreement with experimental data under ex situ Fenton test conditions. The predicted FER under fuel cell operating conditions was underestimated by 2–3 orders of magnitude. It is likely that degradation via side-chain attack is prevalent during open circuit voltage hold tests. The oxidative degradation of PSSA ionomer follows an entirely different pathway, because, in addition to α-hydrogen abstraction by HO•, the aromatic ring effectively scavenges HO• to form an OH-adduct. Follow-up reactions lead to chain scission and formation of a stable hydroxylated degradation product.
Relationship Between I3
− Diffusion in Titania Nanopores Modified with Dyes and Open Circuit Voltage of Dye-Sensitized Solar Cell
Authors: Hayat Azwar , Pandey Shyam S. , Ogomi Yuhei , Hayase Shuzi
Published: April 2011

Relative diffusion rates (Rrel) of I3
− species in titania nanopores modified with various dye molecules were measured. Introduction of polar atoms such as O or F decreased Rrel and open circuit voltage (Voc) of dye-sensitized solar cells (DSC). The results were explained by the fact that slow diffusion of I3
− species in nanopores increases opportunities of charge recombination between electrons in titania layer and I3
− existing in the titania nanopores.
Genetic deficiency of Smad3 protects against murine ischemic acute kidney injury
Authors: Nath Karl A. , Croatt Anthony J. , Warner Gina M. , Grande Joseph P.
Published: April 2011

TGF-β1 contributes to chronic kidney disease, at least in part, via Smad3. TGF-β1 is induced in the kidney following acute ischemia, and there is increasing evidence that TGF-β1 may protect against acute kidney injury. As there is a paucity of information regarding the functional significance of Smad3 in acute kidney injury, the present study explored this issue in a murine model of ischemic acute kidney injury in Smad3+/+ and Smad3−/− mice. We demonstrate that, at 24 h after ischemia, Smad3 is significantly induced in Smad3+/+ mice, whereas Smad3−/− mice fail to express this protein in the kidney in either the sham or postischemic groups. Compared with Smad3+/+ mice, and 24 h following ischemia, Smad3−/− mice exhibited greater preservation of renal function as measured by blood urea nitrogen (BUN) and serum creatinine; less histological injury assessed by both semiquantitative and qualitative analyses; markedly suppressed renal expression of IL-6 and endothelin-1 mRNA (but comparable expression of MCP-1, TNF-α, and heme oxygenase-1 mRNA); and no increase in plasma IL-6 levels, the latter increasing approximately sixfold in postischemic Smad3+/+ mice. We conclude that genetic deficiency of Smad3 confers structural and functional protection against acute ischemic injury to the kidney. We speculate that these effects may be mediated through suppression of IL-6 production. Finally, we suggest that upregulation of Smad3 after an ischemic insult may contribute to the increased risk for chronic kidney disease that occurs after acute renal ischemia.
Increased Na+ and K+ currents in small mouse dorsal root ganglion neurons after ganglion compression
Authors: Fan Ni , Sikand Parul , Donnelly David F. , Ma Chao , LaMotte Robert H.
Published: April 2011

We investigated the effects of chronic compression (CCD) of the L3 and L4 dorsal root ganglion (DRG) on pain behavior in the mouse and on the electrophysiological properties of the small-diameter neuronal cell bodies in the intact ganglion. CCD is a model of human radicular pain produced by intraforaminal stenosis and other disorders affecting the DRG, spinal nerve, or root. On days 1, 3, 5, and 7 after the onset of compression, there was a significant decrease from preoperative values in the threshold mechanical force required to elicit a withdrawal of the foot ipsilateral to the CCD (tactile allodynia). Whole cell patch-clamp recordings were obtained, in vitro, from small-sized somata and, for the first time, in the intact DRG. Under current clamp, CCD neurons exhibited a significantly lower rheobase compared with controls. A few CCD but no control neurons exhibited spontaneous action potentials. CCD neurons showed an increase in the density of TTX-resistant and TTX-sensitive Na+ current. CCD neurons also exhibited an enhanced density of voltage-dependent K+ current, due to an increase in delayed rectifier K+ current, without a change in the transient or “A” current. We conclude that CCD in the mouse produces a model of radicular pain, as we have previously demonstrated in the rat. While the role of enhanced K+ current remains to be elucidated, we speculate that it represents a compensatory neuronal response to reduce ectopic or aberrant levels of neuronal activity produced by the injury.
Chemosensory burst coding by mouse vomeronasal sensory neurons
Authors: Arnson Hannah A. , Holy Timothy E.
Published: April 2011

The capabilities of any sensory system are ultimately constrained by the properties of the sensory neurons: the ability to detect and represent stimuli is limited by noise due to spontaneous activity, and optimal decoding in downstream circuitry must be matched to the nature of the encoding performed at the input. Here, we investigated the firing properties of sensory neurons in the accessory olfactory system, a distinct sensory system specialized for detection of socially relevant odors. Using multielectrode array recording, we observed that sensory neurons are spontaneously active and highly variable across time and trials and that this spontaneous activity limits the ability to distinguish sensory responses from noise. Sensory neuron activity tended to consist of bursts that maintained remarkably consistent statistics during both spontaneous activity and in response to stimulation with sulfated steroids. This, combined with pharmacological and genetic intervention in the signal transduction cascade, indicates that sensory transduction plays a role in shaping overall spontaneous activity. These findings indicate that as-yet unexplored characteristics of the sensory transduction cascade significantly constrain the representation of sensory information by vomeronasal neurons.
Reduced expression of SynGAP, a neuronal GTPase-activating protein, enhances capsaicin-induced peripheral sensitization
Authors: Duarte Djane Braz , Duan Jian-Hong , Nicol Grant D. , Vasko Michael R. , Hingtgen Cynthia M.
Published: April 2011

Synaptic GTPase-activating protein (SynGAP) is a neuronal-specific Ras/Rap-GAP that increases the hydrolysis rate of GTP to GDP, converting Ras/Rap from the active into the inactive form. The Ras protein family modulates a wide range of cellular pathways including those involved in sensitization of sensory neurons. Since GAPs regulate Ras activity, SynGAP might be an important regulator of peripheral sensitization and pain. Therefore, we evaluated excitability, stimulus-evoked release of the neuropeptide calcitonin gene-related peptide (CGRP), and nociception from wild-type (WT) mice and those with a heterozygous mutation of the SynGAP gene ( SynGAP+/−). Our results demonstrate that SynGAP is expressed in primary afferent sensory neurons and that the capsaicin-stimulated CGRP release from spinal cord slices was two-fold higher from SynGAP+/− mice than that observed from WT mouse tissue, consistent with an increase in expression of the capsaicin receptor, transient receptor potential cation channel subfamily V member 1 (TRPV1), in SynGAP+/− dorsal root ganglia. However, there was no difference between the two genotypes in potassium-stimulated release of CGRP, the number of action potentials generated by a ramp of depolarizing current, or mechanical hypernociception elicited by intraplantar injection of capsaicin. In contrast, capsaicin-induced thermal hypernociception occurred at lower doses of capsaicin and had a longer duration in SynGAP+/− mice than WT mice. These results provide the first evidence that SynGAP is an important regulator of neuropeptide release from primary sensory neurons and can modulate capsaicin-induced hypernociception, demonstrating the importance of GAP regulation in signaling pathways that play a role in peripheral sensitization.
Rapid Decrease of CD16 (FcγRIII) Expression on Heat‐Shocked Neutrophils and Their Recognition by Macrophages
Authors: Bzowska Małgorzata , Hamczyk Magda , Skalniak Anna , Guzik Krzysztof
Published: April 2011

Accumulation of neutrophils in the site of inflammation is a
typical mechanism of innate immunity. The accumulated neutrophils
are exposed to stressogenic factors usually associated with
inflammation. Here, we studied response of human peripheral blood
neutrophils subjected to short, febrile‐range heat stress. We
show that 90 min heat stress slowed down the spontaneous apoptosis
of neutrophils. In the absence of typical markers of apoptosis the
heat‐shocked neutrophils induced antiinflammatory effect in human
monocyte‐derived macrophages (hMDMs), yet without being engulfed.
Importantly, the expression of FcγRIII (CD16) was sharply reduced.
Surprisingly, concentration of the soluble CD16 did not change in
heat‐shocked neutrophil supernates indicating that the reduction
of the cell surface CD16 was achieved mainly by inhibition of
fresh CD16 delivery. Inhibitors of 90 kDa heat shock protein
(HSP90), a molecular chaperone found in membrane platforms
together with CD16 and CD11b, significantly increased the observed
effects caused by heat shock. The presented data suggest a novel
systemic aspect of increased temperature which relies on immediate
modification by heat of a neutrophil molecular pattern. This
effect precedes cell death and may be beneficial in the initial
phase of inflammation providing a nonphlogistic signal to
macrophages before it comes from apoptotic cells.
Newton Interpolating Series at m Distinct Points with Coefficients in a Real Banach Algebra
Authors: Groza Ghiocel , Pop Nicolae
Published: April 2011

A real Banach algebra of Newton interpolating series, used to approximate
the solutions of multipoint boundary value problems for ODE′s, is studied.
Semicompatibility and Fixed Point Theorems for Reciprocally Continuous Maps in a Fuzzy Metric Space
Authors: Badshah V. H. , Joshi Varsha
Published: April 2011

The aim of this paper is to prove a common fixed point theorem for six mappings on fuzzy metric space using notion of semicompatibility and reciprocal continuity of maps satisfying an implicit relation. We proposed to reanalysis the theorems of Imdad et al. (2002), Popa (2001), Popa (2002) and Singh and Jain (2005).
Multifocal Tubercular Osteomyelitis: A Case with Atypical Manifestations
Authors: Thawani Mukesh , Hale Elizabeth , Habte-Gabr Eyassu
Published: April 2011

Skeletal tuberculosis (TB) accounts for about 1–2% of all TB cases and 10% of extrapulmonary TB cases. We present a 19-year-old male with multifocal tubercular osteomyelitis, who presented with progressively worsening back pain, weight loss, fatigue, anorexia, decreased mobility, low-grade fever, and night sweats—but without pulmonary involvement.
Social and Health Factors Associated with Physical Activity among Kuwaiti College Students
Authors: Al-Isa Abdulwahab Naser , Campbell Jennifer , Desapriya Ediriweera , Wijesinghe Namal
Published: April 2011

Our aim was to explore the social and health factors that are associated with the level of physical activity among Kuwaiti college students. A random sample of 787 students (48% males and 52% females) was chosen and weight and height were measured to obtain body mass index (BMI, kg/m2). Associated social and health factors were obtained using a questionnaire. Those reporting being physically inactive numbered 354 and the remaining 433 were active. Obesity among males was 13% and was 10.5% among females. The social and health factors that were found to be significantly associated with physical activity among the students were gender (P<.001), marital status (P<.05), BMI category (obese or nonobese) (P<.05), last dental and health checkup (P<.01), desiring a higher degree (P<.001), and countries preferred for visiting (P<.01). Males significantly exceeded females in the practice of physical activity. In conclusion, behavioural modifications, intervention studies, and health education touting the benefits of being physically active should be instituted to increase the practice of sports and other physical activities in order to control and decrease obesity-related morbidity and mortality.
Slave System Dimension Expansion Approach for Robust Synchronization of Chaotic Systems with Unknown Phase Difference
Authors: Mai Huanhuan , Zhang Weiwei , Zhao Yapeng
Published: April 2011

A technique which increased the dimension of slave system is adopted for robust synchronization of chaotic systems with unknown phase difference. The phase difference plays a great role in variation of dynamic behavior of the coupled systems. The phase difference of the sinusoidal forcing term is always assumed to be known in the majority of the existing literature. However, unknown parameter error value has always existed in real problems. This method uses the properties of the triangular function and increases the number of dimensions in the slave system to match the phase of forcing term in the master system. Numerical simulations show that the flexible control variable we first investigated is very important. We expect our results to be of some broader applicabilities.
WHO Surgical Checklist and Its Practical Application in Plastic Surgery
Authors: Abdel-Rehim Shady , Morritt Andrew , Perks Graeme
Published: April 2011

The WHO surgical checklist was introduced to most UK surgical units following the WHO “Safe Surgery Saves Lives” initiative. The aim of this audit was to review patient's safety in the delivery of surgical care and to evaluate the practical application of the new WHO surgical checklist. We conducted a retrospective audit of patients who received operative treatment under general anaesthesia at our Plastic Surgery Department, involving a total number of 90 patients. The WHO form was compared to its former equivalents. Complications or incidents occurring during or after surgery were recorded. Using the department's previous surgical checklist, “Time out” was only performed in only 30% of cases. One patient arrived at theatre reception without a completed consent form, and two clinical incidents were reported without patients suffering harm. Following introduction of current WHO surgical checklist, “Time out” was recorded in 80% of cases. In all cases, the new WHO surgical checklist was used and no incidents were reported. The WHO surgical checklist provides a structured frame work that standardizes the delivery of care across hospitals and specialized units; however, it will take some time and practice for teams to learn to use the checklist effectively and reliably.
Investigation of a Potential Scintigraphic Tracer for Imaging Apoptosis: Radioiodinated Annexin V‐Kunitz Protease Inhibitor Fusion Protein
Authors: Liao Mei-Hsiu , Jan Tong-Rong , Chiang Chao-Chih , Yen Kuo-Chen , Liao Tse-Zung , Chen Ming-Wei , Chi Chin-Wen , Wun Tze-Chein , Yen Tzu-Chen , Wey Shiaw-Pyng
Published: April 2011

Radiolabeled annexin V (ANV) has been widely used for imaging cell apoptosis. Recently, a novel ANV‐Kunitz‐type protease inhibitor fusion protein, ANV‐6L15, was found to be a promising probe for improved apoptosis detection based on its higher affinity to phosphatidylserine (PS) compared to native ANV. The present paper investigates the feasibility of apoptosis detection using radioiodinated ANV‐6L15. Native ANV and ANV‐6L15 were labeled with iodine‐123 and iodine‐125 using Iodogen method. The binding between the radioiodinated proteins and erythrocyte ghosts or chemical‐induced apoptotic cells was examined. ANV‐6L15 can be radioiodinated with high yield (40%−60%) and excellent radiochemical purity (>95%). 123I‐ANV‐6L15 exhibited a higher binding ratio to erythrocyte ghosts and apoptotic cells compared to 123I‐ANV. The biodistribution of 123I‐ANV‐6L15 in mice was also characterized. 123I‐ANV‐6L15 was rapidly cleared from the blood. High uptake in the liver and the kidneys may limit the evaluation of apoptosis in abdominal regions. Our data suggest that radiolabled ANV‐6L15 may be a better scintigraphic tracer than native ANV for apoptosis detection.
Demonstrating Intertumoural Differences in Vascular-Metabolic
Phenotype with Dynamic Contrast-Enhanced CT-PET
Authors: Miles K. A. , Williams R. E. , Yu D. , Griffiths M. R.
Published: April 2011

Purpose. To assess whether the differences in vascular-metabolic relationships between lymphoma masses and colorectal liver metastases predicted from previous histopathological studies can be demonstrated by dynamic contrast-enhanced CT (DCE-CT) combined with fluorodeoxyglucose positron emission tomography (FDG-PET). Methods. DCE-CT and FDG-PET studies were drawn from an imaging archive for patients with either lymphoma masses (n=11) or hepatic metastases from colorectal cancer (CRM: n=12). Tumour vascularity was assessed using DCE-CT measurements of perfusion. Tumour glucose metabolism was expressed as the mean FDG Standardised Uptake Value (SUVFDG). The relationship between metabolism and vascularity in each group was assessed from SUVFDG /perfusion ratios and Pearson correlation coefficients. Results. An SUVFDG threshold of 3.0 was used to designate lymphoma masses as active (AL, n=6) or inactive lymphoma (IL, n=5). Tumour perfusion was significantly higher in AL (0.65 mL/min/mL) than CRM (0.37 mL/min/mL: P=.031) despite similar SUVFDG (5.05 and 5.33, resp.). AL demonstrated higher perfusion values than IL (0.24 mL/min/mL: P=.006). SUVFDG/perfusion was significantly higher in CRM (15.3 min) than IL (4.2 min, P<.01). There was no correlation between SUVFDG and perfusion for any patient group.
Teachers' Experiences with School Choice: Clashing Logics in the Swedish Education System
Authors: Lundström Ulf , Parding Karolina
Published: April 2011

This paper explores the school choice reform in Sweden, a country where a drastic shift in education policy has taken place that includes fast expansion of market solutions and strong state support for competition. Although there are studies examining the school choice reform, few focus on the effects of this reform from a teacher perspective, especially so in the context of Sweden. To this end, this paper examines how Swedish upper secondary teachers in independent (private) and public schools experience their work in relation to school choice reform. This study uses qualitative interviews of 58 teachers from five municipal and three independent upper secondary schools. Its theoretical framework relies on Freidson's distinction between the logic of the profession, the bureaucracy, and the market. The findings indicate that the traditional position of teachers—a position that must negotiate the tension between the logic of the profession and the logic of the bureaucracy—is now in fact challenged by the logic of the market. This study argues that values linked to the logic of the market are imposed on the teachers, and these market values clash with the teachers' values, values based on the logic of the profession.
Comb-Line Filter with Coupling Capacitor in Ground Plane
Authors: Kitamura Toshiaki
Published: April 2011

A comb-line filter with a coupling capacitor in the ground plane is proposed. The filter consists of two quarter-wavelength microstrip resonators. A coupling capacitor is inserted into the ground plane in order to build strong coupling locally along the resonators. The filtering characteristics are investigated through numerical simulations as well as experiments. Filtering characteristics that have attenuation poles at both sides of the passband are obtained. The input susceptances of even and odd modes and coupling coefficients are discussed. The filters using stepped impedance resonators (SIRs) are also discussed, and the effects of the coupling capacitor for an SIR structure are shown.
More Than 200 Genes Required for Methane Formation from H2and CO2and Energy Conservation Are Present inMethanothermobacter marburgensisandMethanothermobacter thermautotrophicus
Authors: Kaster Anne-Kristin , Goenrich Meike , Seedorf Henning , Liesegang Heiko , Wollherr Antje , Gottschalk Gerhard , Thauer Rudolf K.
Published: April 2011

The hydrogenotrophic methanogensMethanothermobacter marburgensisandMethanothermobacter thermautotrophicuscan easily be mass cultured. They have therefore been used almost exclusively to study the biochemistry of methanogenesis from H2and CO2, and the genomes of these two model organisms have been sequenced. The close relationship of the two organisms is reflected in their genomic architecture and coding potential. Within the 1,607 protein coding sequences (CDS) in common, we identified approximately 200 CDS required for the synthesis of the enzymes, coenzymes, and prosthetic groups involved in CO2reduction to methane and in coupling this process with the phosphorylation of ADP. Approximately 20 additional genes, such as those for the biosynthesis of F430and methanofuran and for the posttranslational modifications of the two methyl-coenzyme M reductases, remain to be identified.
Aurora AIs a Repressed Effector Target of the Chromatin Remodeling Protein INI1/hSNF5 Required for Rhabdoid Tumor Cell Survival
Authors: Lee SeungJae , Cimica Velasco , Ramachandra Nandini , Zagzag David , Kalpana Ganjam V.
Published: April 2011

Rhabdoid tumors (RT) are aggressive pediatric malignancies with poor prognosis. INI1/hSNF5 is a component of the chromatin remodeling SWI/SNF complex and a tumor suppressor deleted in RT. Previous microarray studies indicated that reintroduction of INI1/hSNF5 into RT cells leads to repression of a high degree of mitotic genes including Aurora Kinase A (Aurora A, STK6). Here, we found that INI1/SNF5 represses Aurora A transcription in a cell-type–specific manner. INI1-mediated repression was observed in RT and normal cells but not in non-RT cell lines. Chromatin immunoprecipitation (ChIP) assay indicated that INI1/hSNF5 associates with Aurora A promoter in RT and normal cells but not in non-RT cells. Real-time PCR and immunohistochemical analyses of primary human and mouse RTs harboring mutations in INI1/hSNF5 gene indicated that Aurora A was overexpressed/derepressed in these tumor cells, confirming that INI1/hSNF5 represses Aurora A in vivo. Knockdown of Aurora A impaired cell growth, induced mitotic arrest and aberrant nuclear division leading to decreased survival, and increased cell death and caspase 3/7-mediated apoptosis in RT cells (but not in normal cells). These results indicated that Aurora A is a direct downstream target of INI1/hSNF5-mediated repression in RT cells and that loss of INI1/hSNF5 leads to aberrant overexpression of Aurora A in these tumors, which is required for their survival. We propose that a high degree of Aurora A expression may play a role in aggressive behavior of RTs and that targeting expression or activity of this gene is a novel therapeutic strategy for these tumors. Cancer Res; 71(9); 3225–35. ©2011 AACR.
Abstract AACR1-1: Synthetic Lethal Approaches to Cancer Therapy
Authors: Ashworth A
Published: April 2011

A critical link exists between genomic instability and cancer development. This instability can manifest as small changes at the nucleotide level or as gross chromosomal alterations. Mutations in the genes that encode DNA damage response proteins are responsible for a variety of genomic instability syndromes including Hereditary Non-Polyposis Colorectal Carcinoma, Bloom syndrome, Ataxia-telangiectasia, BRCA1 and BRCA2 mutated breast and ovarian cancers and Fanconi anaemia. Similarly epigenetic silencing of genes associated with the maintenance of genomic stability have also been implicated in the pathogenesis of cancer. Here, I discuss how different tumours may be classified not only by tumour site but also by the type of underlying genetic instability. This type of classification may assist in the optimization of treatment regimens as well as informing the development of new therapeutic approaches in particular based on “synthetic lethality”. I will illustrate these principles by demonstrating potential “synthetic lethal” treatments for mismatch repair deficient cancers.

Citation Information: Cancer Res 2010;70(24 Suppl):Abstract nr AACR1-1.
Abstract BSF1-1: Single Cell Analysis of Normal and Tumor Breast Epithelium Reveals Differential Use of Signalling Pathways by Novel Populations
Authors: Clarke MF , N Lobo
Published: April 2011

Primary human tissue contains a complex mixture of cell types which can only be partially purified by cell sorting based on surface markers. To gain further insight into mammary gland and tumor biology, we performed highly parallel single cell multiplexed gene expression measurements on individual normal and malignant mammary cells. This approach enabled discovery of novel normal mammary stem cell markers and gave insights into normal and malignant tissue architecture. We identified two distinct normal mammary stem cell populations: a proliferating, stem cell population that expresses basal cell markers and shows evidence of activation of the Wnt/β-catenin signaling pathway components and a second, Axin2-, CD44-/low quiescent normal stem cell population which does not express basal cell markers. Both populations had similar engraftment ability in vivo, demonstrating that there are likely two physiological stem cell states. Single cell analysis of estrogen receptor positive (ER+) breast tumors revealed similar cellular populations in cancer cells that resemble the normal mammary duct architecture. Remarkably, the expression of therapeutic targets such as growth factor receptors and the estrogen receptor differed between the different cell compartments. Most notably, the Axin2- cell population did not express ER or TOPO2, the target of Adriamycin, one of the most effective drugs for the treatment of breast cancer, suggesting that this population is not directly targeted by many therapeutic agents routinely used for the treatment of ER+ breast cancer. Our results show that single cell analyses might be useful for developing new strategies for treating cancer by identifying the expression of therapeutic targets by each of the cancer cell populations that make up a particular tumor.

Citation Information: Cancer Res 2010;70(24 Suppl):Abstract nr BSF1-1.
Abstract CSF1-1: Breast Cancer Screening: The Radiology Perspective
Authors: Flowers CI
Published: April 2011

Rightly or wrongly, radiologists ‘own’ breast cancer screening, as it is a radiological procedure, administered by the radiology departments. As a result in the USA, radiologists are outraged at what is seen as misuse of published data showing the effectiveness of mammographic screening. In the USA, we do not have true population screening, and rely on women being informed, and having insurance coverage, to enable them to have an annual screening exam. There is no call/recall system, and we do not collect national statistics on breast screening and outcomes. Many low income women are not offered, what to many is a ‘life saving’ test, as a result of State budget cuts.

In comparison with other countries, some of which have National Screening Programs (like the UK NHS BSP, the Netherlands and Sweden), there is support from epidemiology and public health departments, as screening is population based, and therefore a public health measure. The downsides with these programs are funding issues, with Cost-Benefit analysis being used, and QALYs (Quality Adjusted Life Years), to assist committees deciding affordable health policy for the nation. There are differences between Europe and the USA in recommendations for screening as a result, especially in terms of starting at 50 years and having a longer screening interval of 2 years.

In late 2009, the US Preventive Services Task Force recommendations to abandon the guideline to start at age 40 for all women, and to recommend routine screening, unless high risk), until the age of 50 years, met with a storm of criticism by interested parties. The recommendations have largely been largely ignored, except by internists.

However, in the current economic climate, it is becoming increasingly clear that decisions may have to be made on cost-benefit if health-care dollars are limited. The acknowledgment that health policy may have to change, is shown when compromises have to be made. This is demonstrated when screening policy is altered, for example, in the UK, where a decision was made to alter the screening target age, rather than reduce the interval between screens. (The NHS BSP is being extended in 2012 to cover women aged between 47 and 73).

I will be concentrating on the screening guidelines and the different approaches taken between the USA and Europe. I will cover the screening of ‘Normal Risk’ women, and uphold the recommendations of the Society of Breast Imaging, American College of Radiology and the American Cancer Society. I will explain the ‘harms’ of screening and argue that screening recommendations should be made on evidence rather than on the numbers of lives saved.

Citation Information: Cancer Res 2010;70(24 Suppl):Abstract nr CSF1-1.
Abstract ES1-1: Advances in the Neurosurgical Management of CNS Metastases
Authors: EB Claus
Published: April 2011

As the overall survival of patients with metastatic breast cancer improves, greater attention has been drawn to involvement specific to the central nervous system (CNS). Brain metastases are the most common intracranial tumor in adults with breast cancer representing the second most common type of CNS brain metastasis. These lesions are thought to develop in up to 20% of breast cancer patients with over 15,000 new cases predicted in the United States each year. Spinal metastases, some with involvement of the spinal cord, are also a frequent occurrence in the breast cancer patient with up to 30% of patients developing this form of the disease. Unfortunately, new systemic therapies for CNS metastases have had little impact on disease control, a critical factor in the improvement of quality of life and survival for this group of patients. Data from the Surveillance, Epidemiology, and End Results (SEER)-Medicare database reveal that one third of intra-cranial and one-half of spinal breast cancer patients with neurosurgically treated CNS metastases are alive at 1 year and that the overall post-operative survival has increased over time for spinal fusion procedures. We propose to review the current state of knowledge, the existing barriers to more successful neurosurgical treatment, and the future goals for treating CNS metastases with neurosurgical intervention. We will 1) review the clinical factors associated with the development of CNS metastases, 2) summarize current neurosurgical treatment strategies with evidence-based outcome data, 3) highlight possible directions for future research efforts.

Citation Information: Cancer Res 2010;70(24 Suppl):Abstract nr ES1-1.
Abstract ES2-1: DNA Repair Pathways and Tumorigenesis
Authors: Ford JM
Published: April 2011

The genome is constantly undergoing DNA damage from endogenous and environmental sources. DNA damage response pathways detect and repair DNA damage and signal to cell cycle checkpoints to allow repair to take place, thus promoting genomic stability. Multiple DNA repair pathways exist: single-strand damage or base errors are repaired by base excision repair, nucleotide excision repair or mismatch repair, while DNA doublestrand breaks are repaired by nonhomologous end joining or homologous recombination repair. These pathways may be used to repair damage caused by anticancer chemotherapy and radiotherapy. Some defects in DNA damage responses are associated with the genomic instability that is a characteristic of cancer. Targeting the remaining DNA damage response pathways could potentially result in tumor selective therapies. Poly(ADP-ribose) polymerase (PARP) inhibitors have shown great promise in this respect, and early clinical data are beginning to emerge. PARP inhibitors enhance the activity of several DNA damaging and crosslinking chemotherapeutic agents and ionizing radiation. An exciting aspect is the selective toxicity of PARP inhibitors in DNA defective tumors, such as those associated with BRCA mutations or breast cancers exhibiting the triple-negative phenotype. This discovery has led to a paradigm shift in cancer therapy representing a targeted, tumor-specific, nontoxic therapy that is supported by emerging clinical data.

Citation Information: Cancer Res 2010;70(24 Suppl):Abstract nr ES2-1.