bluuebunny/crossref_metadata_2025 huggingface dataset:
Design and Fabrication of 500-kN Large-scale MR Damper
Authors: Tu J.W. , Liu J. , Qu W.L. , Zhou Q. , Cheng H.B. , Cheng X.D.
Published: March 2011

This article presents a thorough investigation of a large-scale MR damper which can produce 500 kN damping force and is prepared for application in the vibration reduction of civil engineering. It is known that it is quite important to prepare a high-performance MR fluid for the large-scale MR damper. The high-performance MR fluid is developed and its essential performance characteristics are tested. Test results show that the sedimentation-proof stability, maximum yield shear stress, and response time of the MR fluid satisfy the requirements for applications of the MR damper in the vibration reduction of engineering structures. The designing process is introduced and several key techniques for the MR damper design, including built-in disk-spring accumulator, magnetic-flux leakage prevented design, leakage prevention of magnetorheological fluid, and stability enhancement of the controller for large-scale MR damper are proposed. Finally, the performance experiments of the MR damper are carried out.
A Morphing Composite Air Inlet with Multiple Stable Shapes
Authors: Daynes S. , Weaver P.M. , Trevarthen J.A.
Published: March 2011

The morphing air inlet is a structure with shape-changing capability. Shapes include that which is flush with an aerodynamic surface and also a submerged divergent channel suitable for use in an aircraft cooling system. The air inlet structure is multistable in order that it can ‘snap’ open and closed and not require any external holding force to maintain its geometry. Structural multistability is achieved using a novel combination of material prestress and bending stiffness tailoring. Analytical and finite element models are developed in order to explain how this multistability is achieved and to predict the actuator requirements and bending strains within the structure. The air inlet design is autoclave manufactured from carbon fiber reinforced plastic and tested as a proof-of-concept demonstrator. The bending stiffness tailoring enables the structure to fulfill the conflicting requirements of large deformations, low mass, and high stiffness to withstand external loads. The simple construction also aids ease of maintenance and reliability. The morphing demonstrator behaves as a one degree-of-freedom system enabling simple actuation solutions, such as inflatable bladders, to be feasible.
Boundaries of Power: Politics of Urban Preservation in Two Chicago Neighborhoods
Authors: Yue Zhang
Published: March 2011

This article examines how the structure of local political representation defines the interest of political actors and affects the outcomes of urban preservation. Although urban preservation is proposed as a strategy of community development in two Chicago neighborhoods (Pilsen and Bronzeville), the outcomes vary significantly. The author argues that the distinct boundaries of aldermanic power play a critical role in shaping the policy process of landmark designation. Aldermanic prerogative gives each alderman veto power over the preservation initiatives in his or her ward. The preservation initiatives within one ward are more likely to receive political support than those across multiple wards. By revealing the mismatch of boundaries between wards and community areas, the study demonstrates the negative impact of political fragmentation on urban preservation.
Olfactory threshold is impaired in early, active multiple sclerosis
Authors: Lutterotti A , Vedovello M , Reindl M , Ehling R , DiPauli F , Kuenz B , Gneiss C , Deisenhammer F , Berger T
Published: March 2011

Background: Olfactory dysfunction has been reported in multiple sclerosis (MS). However, to date no data are available on different qualities of olfactory function, namely odour identification, odour discrimination and odour perception threshold.

Objective: To assess different qualities of olfactory function in patients with MS and correlate these with demographic data, clinical data, depression, quality of life and cognitive functions.

Methods: In this cross-sectional study, 50 patients with MS or clinically isolated syndrome and 30 healthy controls were included. Olfactory function was measured using the Sniffin’ Sticks test.

Results: The scores for odour identification ( p = 0.001), odour perception threshold ( p = 0.037) and the combined score of odour identification, discrimination and perception threshold (TDI, p = 0.002) were significantly lower in MS. Hyposmia for identification ( p = 0.0017), threshold ( p = 0.017) and TDI score ( p = 0.0014) was more frequent in MS. Olfactory threshold was impaired in patients who were clinically active in the previous year ( p = 0.026) and in patients with a disease duration less than 2 years ( p = 0.0093). Identification score was negatively correlated with disease duration ( p = 0.0017). Olfactory function was not associated with disability, depression or quality of life.

Conclusions: We report evidence for qualitatively distinct hyposmia in MS, with increased smell threshold in the early inflammatory phases of the disease and impaired identification with a more widespread chronic disease.
Questions of security: A framework for research
Authors: Valverde Mariana
Published: March 2011

Scholars have noted that we are increasingly being governed in the name of security, in literature that usually treats security as an entity in need of a theory. This article begins by noting that ‘security’ does not need theories, but rather questions that can generate concrete analyses. Three sets of questions are elaborated here. The first concerns the logics of security projects. The second set raises questions of scale and jurisdiction. Finally, governance projects are distinguished by the techniques used. This set of questions about security—which, this article argues, always need to be posed in relation to specific security projects—is a theoretically significant revision of the governmentality literature’s distinction between rationalities and technologies of governance.
A National Ceremony
Authors: Wozniak Jesse , Groves Bob
Published: March 2011

U.S. Census Director Bob Groves sheds light on the scope, mechanics, and mission of his bureau and its most famous project.
The Roots of American Decline
Authors: Lachmann Richard
Published: March 2011

Using historical comparisons, the author analyzes America's faltering international power and argues that it will take more than good will and high hopes to save the empire.
Escape from Suburbia
Authors: Buchner Nick
Published: March 2011

Growing up suburban in America typically suggests a privileged lifestyle. Paradoxically, it can also provide a yearning for change.
In-Home Tele-Rehabilitation Improves Tetraplegic Hand Function
Authors: Kowalczewski Jan , Chong Su Ling , Galea Mary , Prochazka Arthur
Published: March 2011

Background. Spinal cord injury (SCI) survivors with tetraplegia have great difficulty performing activities of daily living (ADLs). Functional electrical stimulation (FES) combined with exercise therapy (ET) can improve hand function, but delivering the treatment is problematic. Objective. To compare 2 ET treatments delivered by in-home tele-therapy (IHT). Methods. Each treatment involved ET, tele-supervised 1 h/d, 5 d/wk for 6 weeks. Treatment 1: “conventional ET” comprised strength training, computer games played with a trackball, and therapeutic electrical stimulation (TES). Treatment 2: “ReJoyce ET” comprised FES-ET on a workstation, the Rehabilitation Joystick for Computerized Exercise (ReJoyce) with which participants played computer games associated with ADLs. Participants were block-randomized into group 1 receiving conventional ET first, followed by 1-month washout, and then ReJoyce ET and group 2 in reverse order. In all, 13 participants took part, 5 completing the study with both hands, such that both groups had a sample size of 9. Primary outcome measure: Action Research Arm Test (ARAT). Secondary outcome measures: grasp and pinch forces and the ReJoyce automated hand function test (RAHFT). Results. ARAT scores improved more after ReJoyce ET (13.0% ± 9.8%) than after conventional ET (4.0% ± 9.6%; F = 10.6, P < .01). RAHFT scores also improved more after ReJoyce ET (16.9% ± 8.6%) than conventional ET (3.3% ± 10.2%; F = 20.4, P < .01). Conclusions. FES-ET on a workstation, supervised over the Internet, is feasible and may be effective for patients who can meet the residual motor function requirements of our study.
Articular cartilage skiving: the concept defined
Authors: Takemoto R. C. , Gage M. J. , Rybak L. , Walsh M. , Egol K. A.
Published: March 2011

‘Skiving’ is commonly used to refer to the condition when the subchondral plate is disrupted and the overlying cartilage physically displaced without the screw tip entering the joint. In this study we sought to define radiographic parameters of skiving and compare radiographs with computed tomography (CT) for accuracy in determining joint skiving. Cadaveric specimens of the distal radius were implanted with a volar plate and screws. Arthrotomies were performed to definitively assess the positions of the screws. Standard and anatomic tilt radiographs as well as CT were performed. Orthopaedic surgeons and radiologists evaluated the images and reported whether screw penetration or skiving had occurred. For screws which penetrated or skived, measurements were made to record the distances from the screw tips to the subchondral plate. Sensitivity, specificity and percent correct interpretations were 53%, 83%, 60% respectively for radiographs; and 100%, 72%, 69% for CT. Screws penetrating the articular surface protruded an average 2.3 mm (range 2–2.6 mm) from the subchondral plate and those skiving protruded 1.4 mm (range 1–1.8 mm). This study shows that articular skiving can occur with penetration of the subchondral plate of up to 1.8 mm. CT has a greater sensitivity and lower specificity in determining skiving compared to radiographs.
New and investigational treatments in cystic fibrosis
Authors: Narasimhan Mangala , Cohen Rubin
Published: March 2011

Cystic fibrosis (CF) is an autosomal recessive disorder that affects approximately 1 in 3000 Caucasian births, or 30,000 individuals in the US and 70,000 worldwide. The discovery of the CF gene, isolation of the CFTR protein and understanding of molecular mechanisms behind the clinical expression of CF are being translated into newer treatments. Treatments for CF and its manifestations are discussed in this article including inhaled antibiotics, hydrator therapies, anti-inflammatory agents and protein modifiers. New and experimental treatments that are in development are also discussed. Outcomes for these treatments are forced expiratory volume in one second (FEV1) improvement, CF-related quality of life, use of intravenous antibiotics and frequency of exacerbations and hospitalizations.
A Multidimensional Scale of Switching Barriers in the Full-Service Restaurant Industry
Authors: Han Heesup , Back Ki-Joon , Kim Yun-Hi
Published: March 2011

This research attempted to develop a measurement scale of switching barriers in full-service restaurants by identifying existing components of switching barriers. A qualitative procedure identified the following four categories of switching barriers: preference, switching costs, relational investment, and lack of alternatives. A further quantitative analysis resulted in production of a multi-item scale of switching barriers. The quantitative analysis found that the two positive dimensions (preference and relational investment) were far stronger barriers in encouraging patrons to return to a restaurant than were negative barriers (switching costs and lack of alternatives) in terms of keeping customers from defecting. As a caveat, due to sample limitations, the findings apply only to full-service restaurants in the United States.
Race Differences in Tipping: Testing the Role of Norm Familiarity
Authors: Lynn Michael
Published: March 2011

On average, blacks tip less than whites in the United States. As a result, many servers dislike waiting on black tables and deliver inferior service to those blacks seated in their sections. Furthermore, this race difference makes it difficult to attract and retain waitstaff in predominately black neighborhoods, which makes such neighborhoods less attractive places for corporations to locate full-service restaurants. To address these issues, race differences in tipping need to be sizably reduced, which requires an understanding of their underlying causes. This study tests and supports the role of norm familiarity in producing race differences in tipping by demonstrating that norm awareness mediates those differences in tipping and that race does not moderate the effects of norm awareness on tipping. These results support the idea that race differences in tipping can be sizably reduced by educating blacks about appropriate tipping norms, so restaurant managers as well as major industry organizations are encouraged to engage in such educational campaigns.
A Comparison of Cold-Water Thawing Options in Chinese Restaurants
Authors: Lo Jennifer Y. , Chan Wilco W. , Wong Kevin
Published: March 2011

Considering all types of restaurants in Hong Kong, Chinese restaurants have the greatest numerical count, and they represent a significant proportion of local restaurant receipts. Chinese restaurants are also very popular all over the world. However, previous researches showed that Chinese restaurants generally consume more water than other types of restaurant. Specifically, the unique cold-water thawing process in commercial Chinese cooking may increase water consumption in Chinese restaurants. This unique feature has yet been explored in printed literature, thus two case studies and a series of field tests were conducted to examine the cold-water thawing process in Chinese restaurants. The aims were to determine the proportion of water consumed by cold-water thawing, compare the performance and estimate the payback period of various cold-water thawing options. Findings showed that cold-water thawing accounted for around 30% of the water consumption in the studied restaurants. Among various cold-water thawing options, the thawing machine and the microbubble machine showed better overall performance. Their payback periods were around 15.5 months and 10 months respectively. The information and recommendation from this paper can serve as a useful reference for restaurant investors, operators, managers, and consultants in controlling water consumption, and minimizing sewage-related environmental impacts.
The Peroxisomal Targeting Signal 1 in sterol carrier protein 2 is autonomous and essential for receptor recognition
Authors: Williams Chris P , Schueller Nicole , Thompson Colin A , van den Berg Marlene , Van Haren Simon D , Erdmann Ralf , Bond Charles S , Distel Ben , Schliebs Wolfgang , Wilmanns Matthias , Stanley Will A
Published: March 2011

Background

The majority of peroxisomal matrix proteins destined for translocation into the peroxisomal lumen are recognised via a C-terminal Peroxisomal Target Signal type 1 by the cycling receptor Pex5p. The only structure to date of Pex5p in complex with a cargo protein is that of the C-terminal cargo-binding domain of the receptor with sterol carrier protein 2, a small, model peroxisomal protein. In this study, we have tested the contribution of a second, ancillary receptor-cargo binding site, which was found in addition to the characterised Peroxisomal Target Signal type 1.

Results

To investigate the function of this secondary interface we have mutated two key residues from the ancillary binding site and analyzed the level of binding first by a yeast-two-hybrid assay, followed by quantitative measurement of the binding affinity and kinetics of purified protein components and finally, by in vivo measurements, to determine translocation capability. While a moderate but significant reduction of the interaction was found in binding assays, we were not able to measure any significant defects in vivo.

Conclusions

Our data therefore suggest that at least in the case of sterol carrier protein 2 the contribution of the second binding site is not essential for peroxisomal import. At this stage, however, we cannot rule out that other cargo proteins may require this ancillary binding site.
MIR@NT@N: a framework integrating transcription factors, microRNAs and their targets to identify sub-network motifs in a meta-regulation network model
Authors: Le Béchec Antony , Portales-Casamar Elodie , Vetter Guillaume , Moes Michèle , Zindy Pierre-Joachim , Saumet Anne , Arenillas David , Theillet Charles , Wasserman Wyeth W , Lecellier Charles-Henri , Friederich Evelyne
Published: March 2011

Background

To understand biological processes and diseases, it is crucial to unravel the concerted interplay of transcription factors (TFs), microRNAs (miRNAs) and their targets within regulatory networks and fundamental sub-networks. An integrative computational resource generating a comprehensive view of these regulatory molecular interactions at a genome-wide scale would be of great interest to biologists, but is not available to date.

Results

To identify and analyze molecular interaction networks, we developed MIR@NT@N, an integrative approach based on a meta-regulation network model and a large-scale database. MIR@NT@N uses a graph-based approach to predict novel molecular actors across multiple regulatory processes (i.e. TFs acting on protein-coding or miRNA genes, or miRNAs acting on messenger RNAs). Exploiting these predictions, the user can generate networks and further analyze them to identify sub-networks, including motifs such as feedback and feedforward loops (FBL and FFL). In addition, networks can be built from lists of molecular actors with an a priori role in a given biological process to predict novel and unanticipated interactions. Analyses can be contextualized and filtered by integrating additional information such as microarray expression data. All results, including generated graphs, can be visualized, saved and exported into various formats. MIR@NT@N performances have been evaluated using published data and then applied to the regulatory program underlying epithelium to mesenchyme transition (EMT), an evolutionary-conserved process which is implicated in embryonic development and disease.

Conclusions

MIR@NT@N is an effective computational approach to identify novel molecular regulations and to predict gene regulatory networks and sub-networks including conserved motifs within a given biological context. Taking advantage of the M@IA environment, MIR@NT@N is a user-friendly web resource freely available at http://mironton.uni.lu which will be updated on a regular basis.
Intravenous ascorbic acid to prevent and treat cancer-associated sepsis?
Authors: Ichim Thomas E , Minev Boris , Braciak Todd , Luna Brandon , Hunninghake Ron , Mikirova Nina A , Jackson James A , Gonzalez Michael J , Miranda-Massari Jorge R , Alexandrescu Doru T , Dasanu Constantin A , Bogin Vladimir , Ancans Janis , Stevens R Brian , Markosian Boris , Koropatnick James , Chen Chien-Shing , Riordan Neil H
Published: March 2011

The history of ascorbic acid (AA) and cancer has been marked with controversy. Clinical studies evaluating AA in cancer outcome continue to the present day. However, the wealth of data suggesting that AA may be highly beneficial in addressing cancer-associated inflammation, particularly progression to systemic inflammatory response syndrome (SIRS) and multi organ failure (MOF), has been largely overlooked. Patients with advanced cancer are generally deficient in AA. Once these patients develop septic symptoms, a further decrease in ascorbic acid levels occurs. Given the known role of ascorbate in: a) maintaining endothelial and suppression of inflammatory markers; b) protection from sepsis in animal models; and c) direct antineoplastic effects, we propose the use of ascorbate as an adjuvant to existing modalities in the treatment and prevention of cancer-associated sepsis.
Hf-based high-k materials for Si nanocrystal floating gate memories
Authors: Khomenkova Larysa , Sahu Bhabani S , Slaoui Abdelilah , Gourbilleau Fabrice
Published: March 2011

Pure and Si-rich HfO2 layers fabricated by radio frequency sputtering were utilized as alternative tunnel oxide layers for high-k/Si-nanocrystals-SiO2/SiO2 memory structures. The effect of Si incorporation on the properties of Hf-based tunnel layer was investigated. The Si-rich SiO2 active layers were used as charge storage layers, and their properties were studied versus deposition conditions and annealing treatment. The capacitance-voltage measurements were performed to study the charge trapping characteristics of these structures. It was shown that with specific deposition conditions and annealing treatment, a large memory window of about 6.8 V is achievable at a sweeping voltage of ± 6 V, indicating the utility of these stack structures for low-operating-voltage nonvolatile memory devices.
Promotion of allergic immune responses by intranasally-administrated nanosilica particles in mice
Authors: Yoshida Tokuyuki , Yoshioka Yasuo , Fujimura Maho , Yamashita Kohei , Higashisaka Kazuma , Morishita Yuki , Kayamuro Hiroyuki , Nabeshi Hiromi , Nagano Kazuya , Abe Yasuhiro , Kamada Haruhiko , Tsunoda Shin-ichi , Itoh Norio , Yoshikawa Tomoaki , Tsutsumi Yasuo
Published: March 2011

With the increase in use of nanomaterials, there is growing concern regarding their potential health risks. However, few studies have assessed the role of the different physical characteristics of nanomaterials in allergic responses. Here, we examined whether intranasally administered silica particles of various sizes have the capacity to promote allergic immune responses in mice. We used nanosilica particles with diameters of 30 or 70 nm (nSP30 or nSP70, respectively), and conventional micro-sized silica particles with diameters of 300 or 1000 nm (nSP300 or mSP1000, respectively). Mice were intranasally exposed to ovalbumin (OVA) plus each silica particle, and the levels of OVA-specific antibodies (Abs) in the plasma were determined. Intranasal exposure to OVA plus smaller nanosilica particles tended to induce a higher level of OVA-specific immunoglobulin (Ig) E, IgG and IgG1 Abs than did exposure to OVA plus larger silica particles. Splenocytes from mice exposed to OVA plus nSP30 secreted higher levels of Th2-type cytokines than mice exposed to OVA alone. Taken together, these results indicate that nanosilica particles can induce allergen-specific Th2-type allergic immune responses in vivo. This study provides the foundations for the establishment of safe and effective forms of nanosilica particles.
Micro-spectroscopy on silicon wafers and solar cells
Authors: Gundel Paul , Schubert Martin C , Heinz Friedemann D , Woehl Robert , Benick Jan , Giesecke Johannes A , Suwito Dominik , Warta Wilhelm
Published: March 2011

Micro-Raman (μRS) and micro-photoluminescence spectroscopy (μPLS) are demonstrated as valuable characterization techniques for fundamental research on silicon as well as for technological issues in the photovoltaic production. We measure the quantitative carrier recombination lifetime and the doping density with submicron resolution by μPLS and μRS. μPLS utilizes the carrier diffusion from a point excitation source and μRS the hole density-dependent Fano resonances of the first order Raman peak. This is demonstrated on micro defects in multicrystalline silicon. In comparison with the stress measurement by μRS, these measurements reveal the influence of stress on the recombination activity of metal precipitates. This can be attributed to the strong stress dependence of the carrier mobility (piezoresistance) of silicon. With the aim of evaluating technological process steps, Fano resonances in μRS measurements are analyzed for the determination of the doping density and the carrier lifetime in selective emitters, laser fired doping structures, and back surface fields, while μPLS can show the micron-sized damage induced by the respective processes.
Isolation and characterization of two new hepatitis E virus genotype 1 strains from two mini-outbreaks in Lahore, Pakistan
Authors: Iqbal Tahir , Idrees Muhammad , Ali Liaqat , Hussain Abrar , Ali Muhammad , Butt Sadia , Yousaf Muhammad Zubair , Sabar Muhammad Farooq
Published: March 2011

Background

Pakistan is a highly endemic area for hepatitis E virus (HEV) infection. The aim of the current study was to isolate and characterize strains of HEV in two mini outbreaks.

Results

RNA was extracted and reverse transcribed to cDNA. Nested PCR was done for the detection of HEV RNA. The positive bands were eluted, cloned in TA vector and sequenced in both directions using genetic Analyzer (Applied Biosystem Inc, USA). Phylogenetic analysis was done using MEGA4 software. We isolated two new HEV genotype-1 strains from Lahore, Pakistan, based on cloning and sequencing of ORF2 region.

Conclusions

Our study suggest that both the human HEV strains were closely related to the Sar-55 but different from the Abb-2B and 87-Pakistan-B HEV isolates sharing 88-91% sequence identity to Pakistani isolate Sar-55. These results indicated that Sar-55 is the main endemic HEV strain in various areas of the country.
Automatic gravity optimization of 2.5D strike listric fault sources with analytically defined fault planes and depth-dependent density
Authors: Chakravarthi V.
Published: March 2011

An automatic gravity inversion technique in the space domain simultaneously estimates the parameters of strike-limited listric fault sources and regional gravity background from a set of observed Bouguer gravity anomalies. The fault profile and regional effect are described by unknown polynomial functions of arbitrary but prescribed degree. Furthermore, the density contrast within the fault structure is presumed to be known, according to a prescribed parameterized nonlinear function of depth, in geologic settings where the detached downthrown block consists of a series of sedimentary beds whose density increases with depth. The inversion is automatic in that it initializes and determines polynomial coefficients for the fault boundary and regional gravity background from a set of observed Bouguer gravity anomalies and improves them iteratively until the modeled gravity anomalies mimic the observed anomalies. An analysis of a set of gravity anomalies attributable to a synthetic model of a listric fault structure in the presence of pseudorandom noise with and without regional background has disclosed that the algorithm yields reliable interpretations with modest error in model geometry, even in the presence of pseudorandom noise. In the presence of regional gravity background and pseudorandom noise, the estimated parameters of the structure deviate marginally from the true ones. The derived density-depth model of the Jharia coal basin in India, a pull-apart basin, has been used to analyze the observed Bouguer gravity anomalies of a boundary fault. The interpretation has yielded information consistent with drilling results and geologic setting of the basin.
Gonadotropin-Releasing Hormone Induces miR-132 and miR-212 to Regulate Cellular Morphology and Migration in Immortalized LβT2 Pituitary Gonadotrope Cells
Authors: Godoy Joseph , Nishimura Marin , Webster Nicholas J. G.
Published: March 2011

GnRH is central to the regulation of reproductive function. It acts on pituitary gonadotropes to stimulate LH and FSH synthesis and secretion. We had previously presented evidence for translational control of LHβ synthesis; therefore we investigated whether micro-RNAs might play a role in GnRH regulation in LβT2 cells. We show here that GnRH strongly induces the AK006051 gene transcript that encodes two micro-RNAs, miR-132 and miR-212, within the first intron. We show furthermore that the AK006051 promoter region is highly GnRH responsive. We verify that the p250Rho GTPase activating protein (GAP) is a target of miR-132/212 and show that GnRH treatment leads to a decrease in mRNA and protein expression. This reduction is blocked by an anti-miR to miR-132/212 and mimicked by a pre-miR-132. GnRH inhibits p250RhoGAP expression through a miR-132/212 response element within the 3′-untranslated region. The loss of p250RhoGAP expression leads to activation of Rac and marked increases in both the number and length of neurite-like processes extending from the cell. Knockdown of p250RhoGAP by small interfering RNA induces the same morphological changes observed with GnRH treatment. In addition, loss of p250RhoGAP causes an increase in cellular motility. Our findings suggest a novel pathway regulating long-term changes in cellular motility and process formation via the GnRH induction of miR-132/212 with the subsequent down-regulation of p250RhoGAP.
Zebrafish embryo screen for mycobacterial genes involved in the initiation of granuloma formation reveals a newly identified ESX-1 component
Authors: Stoop Esther J. M. , Schipper Tim , Rosendahl Huber Sietske K. , Nezhinsky Alexander E. , Verbeek Fons J. , Gurcha Sudagar S. , Besra Gurdyal S. , Vandenbroucke-Grauls Christina M. J. E. , Bitter Wilbert , van der Sar Astrid M.
Published: March 2011

The hallmark of tuberculosis (TB) is the formation of granulomas, which are clusters of infected macrophages surrounded by additional macrophages, neutrophils and lymphocytes. Although it has long been thought that granulomas are beneficial for the host, there is evidence that mycobacteria also promote the formation of these structures. In this study, we aimed to identify new mycobacterial factors involved in the initial stages of granuloma formation. We exploited the zebrafish embryo Mycobacterium marinum infection model to study initiation of granuloma formation and developed an in vivo screen to select for random M. marinum mutants that were unable to induce granuloma formation efficiently. Upon screening 200 mutants, three mutants repeatedly initiated reduced granuloma formation. One of the mutants was found to be defective in the espL gene, which is located in the ESX-1 cluster. The ESX-1 cluster is disrupted in the Mycobacterium bovis BCG vaccine strain and encodes a specialized secretion system known to be important for granuloma formation and virulence. Although espL has not been implicated in protein secretion before, we observed a strong effect on the secretion of the ESX-1 substrates ESAT-6 and EspE. We conclude that our zebrafish embryo M. marinum screen is a useful tool to identify mycobacterial genes involved in the initial stages of granuloma formation and that we have identified a new component of the ESX-1 secretion system. We are confident that our approach will contribute to the knowledge of mycobacterial virulence and could be helpful for the development of new TB vaccines.
InACTIVatINg cancer cachexia
Authors: Mathew Sam J.
Published: March 2011

Summary of and comment on a recent Cell paper entitled ‘Reversal of cancer cachexia and muscle wasting by ActRIIB antagonism leads to prolonged survival’ (Zhou et al., 2010).
Kinetics of diffusive phase transformations: From local equilibrium to mobility-driven migration of thick interfaces
Authors: Gamsjäger Ernst
Published: March 2011

It is a prerequisite for the occurrence of diffusive phase transformations that the system is in an off-equilibrium condition. The time-dependent development of the variables until equilibrium or steady-state conditions are reached can be calculated by solving the evolution equations that can be derived from the principle of maximum entropy production. These equations provide the theoretical framework for the kinetics of diffusive phase transformations. In this work, the development from sharp interface-local equilibrium (SI-LE) models to thick interface-finite mobility (TI-FM) models is reviewed and presented in the light of the above-mentioned principle. Experimental results indicate that the kinetics of diffusive solid-state phase transformations can, at least in certain ranges of composition and temperature, be modeled in a satisfactory manner by the TI-FM approach only.
In Situ Scanning Electron Microscope Observation and Finite Element Method Analysis of Delayed Hydride Cracking Propagation in Zircaloy-2 Fuel Cladding Tubes
Authors: Kubo Toshio , Muta Hiroaki , Yamanaka Shinsuke , Uno Masayoshi , Ogata Keizo
Published: March 2011

The objective of the present research is to build a modeling method for delayed hydride cracking (DHC) of zirconium alloys. DHC tests were carried out on Zircaloy-2 cladding tubes in the chamber of a scanning electron microscope to directly observe the crack propagation and measure the crack velocity in the radial direction. These in situ observations showed that a sharply tipped crack propagated at a relatively high rate, while the velocity decreased when the crack tip was blunted, supporting the occurrence of intermittent crack propagation that could be expected from the DHC mechanism. V-KI curves or diagrams of crack velocity, V, versus stress intensity factor at a crack tip, KI, were obtained as a function of 0.2 % offset yield stress, hydride orientation, and pre-crack depth. The steady state crack velocity and the threshold stress intensity factor for the onset of the crack propagation tended to increase or decrease, respectively, with an increase in the 0.2 % offset yield stress. Analyses of stress distribution and hydrogen diffusion around a crack tip were made using a finite element computer code. The analyses showed that a strong hydrostatic pressure field was generated concentrically around the crack tip and hydrogen diffused towards the crack tip according to the hydrostatic pressure gradient. The crack velocity was estimated from the calculated hydrogen flux rate assuming the critical hydrogen quantity for the crack propagation. There was good agreement between the experiments and the calculations regarding the crack velocity and its dependency on KI. Calculations showed that the increase in the 0.2 % offset yield stress would accelerate the crack propagation by increasing the hydrostatic pressure at the crack tip.
Wear Advantage of a Rotating Bearing Knee–An In Vitro Study
Authors: Angibaud Laurent D. , Burstein Albert , Balcom William B. , Miller Gary J.
Published: March 2011

Mobile-bearing knees such as rotating platform knee (RPK) prosthetic implant systems were developed to improve knee kinematics, reduce torque transmitted to the implant-bone interface, allow implant self-alignment, and reduce wear. This study evaluated the wear performance of a RPK implant [the Optetrak® (RBKTM)] characterized by a wave-shaped distal bearing intended to reduce the risk of central tibial insert peg wear by shielding it from loading. This system was compared to its clinically proven fixed-bearing knee counterpart (the FBK) (1) as well as other historical RPKs (2). Wear tests were conducted by an independent laboratory using a procedure following ISO 14243-1 with the exception of the fluid test medium. The laboratory disclosed individual wear rates for historical RPK systems (n=9). After correcting for fluid test medium absorption, the net wear rate averaged 2.11±0.47 and 3.00±0.47  mg/Mc for the RBK and the FBK, respectively (P>0.05), while the mean wear rate reported for the historical RPK systems was 6.65 mg/Mc. Visual analysis after testing showed all evaluated RBK inserts exhibited identical contact patterns. Microscopic visual examination revealed minimal central peg and tibial tray bore wear. Based on this study, wear performance was similar for both the RBK and FBK systems. Compared to historical RPKs, the RBK was associated with a lower wear rate, demonstrating that the wave-shaped bearing reduces wear caused by contact between the central peg and tibial tray bore (when tested on a knee simulator).
ZIRLO® Irradiation Creep Stress Dependence in Compression and Tension
Authors: Foster John Paul , Baranwal Rita
Published: March 2011

Fuel operating margins in recent years have decreased due to increases in fuel duty. In response, Westinghouse has developed an improved version of Standard ZIRLO®, denoted as Optimized ZIRLO™. This paper is a continuation of a previous paper reported by Foster et al. in 2009, which presented methods used to develop Optimized ZIRLO from Standard ZIRLO. The previous paper only outlined the experimental methods used to determine irradiation creep. This paper presents the detailed methods used to determine in-reactor creep and growth. In addition, in-reactor creep stress dependence in tension and compression will be evaluated. The results show that the: (1) In-reactor creep compliance is the same in tension and compression and (2) if total in-reactor strain is split into irradiation growth and creep components: (a) Deviatoric hoop stress component and/or the stress difference of hoop minis radial is the driving force for irradiation creep and (b) irradiation creep in tension is the same as compression. These are the first experimental results that explicitly demonstrate the relationship between irradiation creep (or alternately plastic deformation under a neutron flux) with the deviatoric hoop stress component and/or the stress difference of hoop minis radial.
Development of Two Sample Preparation Methods for Determination of Lead in Composite Dust Wipe Samples
Authors: White Kenneth T. , Dewalt F. Gary , Cox David C. , Schmehl Richard , Friedman Warren , Pinzer Eugene A.
Published: March 2011

Sample preparation methods for four-wipe composite dust wipe samples, used by nine different laboratories accredited under the U.S. Environmental Protection Agency (EPA) National Lead Laboratory Accreditation Program (NLLAP), were evaluated to select two methods most likely to provide the best overall performance among multiple laboratories, based on accuracy, precision and practicality of the methods. The best performing methods involved (1) hot nitric acid/hydrogen peroxide digestion and (2) nitric acid ultrasonication. In a second round of testing, two sets of composite dust wipe samples with known amounts of lead were submitted blind to each of the nine laboratories to be prepared for analysis using these two sample preparation methods. Results showed that both methods are capable of meeting all EPA NLLAP requirements for accuracy (recovery) and precision. The ultrasonication method had superior performance at lower cost.
Standardized Polymer Durometry
Authors: Mix A. W. , Giacomin A. J.
Published: March 2011

Polymer durometry is the measurement of the hardness of plastic and rubber materials using an indentor. Many different hardness scales and indentor geometries have been standardized for durometry. Indentation into a solid is governed by linear elastic mechanics, and this paper relates the Young’s modulus to standardized hardness scale reading. We nondimensionalized these indentation mechanics, to uncover a normalized Young’s modulus, Υ, and the dimensionless hardness, ℋ, and then, a new dimensionless indentor stiffness that we call mechanical indentability, Mi. We use Mi for classifying standardized hardness scales. Our results allow practitioners to determine the Young’s modulus from measured hardness. Further, our results can be used to convert between hardness scales, not only between hardness scales of the same indentor geometry, but also between those of differing geometry.
Fundamental Mechanisms in Laser and Electron Beam Processing of Semiconductors
Authors: Brown Walter L.
Published: March 2011

A few of the new developments in understanding transient laser and electron beam processes in semiconductors and a few of the still unresolved questions are summarized.
Adsorption of Oxygen in Laser-Induced Amorphous Silicon
Authors: Liu Yung S. , Chiang S. W. , Bacon F.
Published: March 2011

Amorphous silicon has been produced on a single crystalline silicon surface by intense UV laser radiation at 266 nm followed by rapid quenching. In addition, formation of oxide of several tens of nanometers has been observed when irradiation takes place in air or in O2 ambient. Various experimental techniques including Transmission Electron Microscopy (TEM), sputtered Auger Electron Spectroscopy (AES), and differential Fourier-transform IR spectroscopy (FT-IR) have been employed to study adsorption of oxygen during rapid melting and resolidification process. The present results suggest a new processing technique for forming thin oxide film, namely, “Laser-induced oxidation.”
A Simple Optical Pyrometer for in Situ Temperature Measurement During Cw Argon Laser Annealing
Authors: Sedgwick T.O.
Published: March 2011

A standard optical disappearing hot wire micropyrometer was modified with a long working distance magnifier to enlarge the laser heated spot so that the maximum temperature of the center of the spot could be observed and measured with some certainty. In situ temperature measurements were made on As ion implanted Si <100> chips using an Argon Ion laser with the beam slightly defocused to a 50–100μm diameter spot on the Si surface. The data curves show a linear function of measured temperature with laser power up until the melting point is reached. By using the Si m.p. as a calibration point, the temperature can be reproducibly measured within a few tens of degrees. Comparisons of actual re-growth rates with those calculated from the well known solid state Si regrowth expression as a function of temperature yields good agreement between measured and calculated temperature.
Device Performance of Laser Annealed Double Heterostructure GaAlAs Materials
Authors: Brett M.J. , Rostworowski J.A. , Parsons R.R. , Springthorpe A.J. , Look C.M. , Dyment J.C.
Published: March 2011

We have laser annealed double heterostructure GaAlAs material with homogeneous ruby laser pulses such that maximum laser light absorption occurs in the active layer. With laser anneal intensities sufficient to melt the active layer, the radiative efficiency of the double heterostructures was reduced by a factor of two. Performance of electroluminescent devices fabricated from annealed material was much worse than performance of devices fabricated from unannealed material.
Effects of Pulsed Laser Irradiation on Thermal Oxides of Silicon
Authors: Lloyd Crosthwait D. , Shah Rajiv R. , Brown George A. , Mays Robert
Published: March 2011

The electrical effects associated with pulsed laser irradiation of thermal oxides of silicon were investigated. Three of the functions performed by thermal oxides are control of field effects, junction passivation and electrical isolation. Representative oxide thicknesses suitable for these applications were studied: ≈ 100 nm; ≈ 500 nm and ≥, 1.0 μm respectively. The oxides were irradiated by a repetitively Q-switched Nd 3+:YAG laser operated at the fundamental frequency. The key laser parameters of energy and power density were varied over a wide range, from no change to the onset of discernible change and irreversible damage. The range of energy densities over which the oxide was not electrically degraded was established for each thickness of the oxide. This range of energy densities is compared to the useful range of energy densities for annealing polysilicon and for activating an implant through an oxide. The electrical data was obtained using a mercury probe and through the analysis of a large number of MOS capacitors formed on the irradiated oxides. Parameters measured include: breakdown voltages, surface state charge densities and flat band voltages.
Characterization Techniques For Laser-Annealed Polysilicon on Insulating Layers
Authors: Schott J. T. , Comer J. J.
Published: March 2011

Various characterization techniques are applied to pulsed and cw laser-annealed polysilicon layers deposited on oxide layers. The results are used to compare these techniques as to the type and completeness of information provided, as well as sample preparation requirements and general ease or difficulty of measurement. The techniques employed include scanning electron microscopy (SEM), electron channeling micrographs and selected area channeling patterns (SACP), reflection (high energy) electron diffraction (RHEED), transmission electron microscopy (TEM) and selected area diffraction (SAD), x-ray diffraction, optical techniques and etching techniques.
Thermally-Assisted Pulsed-Laser Annealing of SOS
Authors: Yamada Masayoshi , Yamazaki Ken-Ichi , Kotani Hisakazu , Yamamoto Keiichi , Abe Kenji
Published: March 2011

Thermally-assisted pulsed-laser annealing has been performed on ion-implanted silicon-on-sapphire(SOS) by irradiating Q-switched(20 nsec) ruby laser light during thermally heating. Raman scattering measurements have been made to estimate the residual strain of the annealed SOS. It was observed that Raman shift of SOS annealed in the temperature range of 400°C to 500°C was very close to that of single crystal silicon and the depolarization factor(the Raman intensity ratio of allowed z(xy)z to forbidden z(xx)z scattering configuration) was infinite, while Raman shift of SOS annealed at room temperature was shifted down to about 5 cm-1 and the depolarization factor was finite. It was found that the residual strain of SOS was relieved by the thermally-assisted pulsed-laser annealing, but the residual strain of SOS annealed at room temperature was inhomogeneous and attained to 7×10−3. The annealing temperature dependences of the residual strains were not explained well with a strictly thermal melting and recrystallization model in conjunction with the thermal expansion difference between silicon and sapphire, and suggested to need a new model.
Deposition of Zinc Selenide by Atomic Layer Epitaxy for Multilayer X-Ray Optics
Authors: Shurtleff J.K. , Allred D.D. , Perkins R.T. , Thorne J.M.
Published: March 2011

Thin film deposition techniques currently being used to produce multilayer x-ray optics (MXOs) have difficulty producing smooth, uniform multilayers with d-spacings less than about twelve angstroms. We are investigating atomic layer epitaxy (ALE) as an alternative to these techniques.

ALE is a chemical vapor deposition technique which deposits an atomic layer of material during each cycle of the deposition process. The thickness of a film deposited by ALE depends only on the number of cycles. Multilayers deposited by ALE should be smooth and uniform with precise d-spacings which makes ALE an excellent technique for producing multilayer x-ray optics.

We have designed and built an ALE system and we have used this system to deposit ZnSe using diethyl zinc and hydrogen selenide.
Spatial Light Modulator Using A CDS Thin Film Photocapacitor
Authors: Reichman Joseph
Published: March 2011

A brief summary is given of the characterization of an optically addressed Spatial Light Modulator (SLM) that uses a thin film of CdS as the hhotosensor and a liquid crystal as the electro-optic material. The required ghdark impedance of the CdS thin film is achieved by a depletion region created by surface acceptor states. Analysis of the SLM complex impedance as a function of frequency and illumination indicates that the voltage switching is due to the reduction in impedance with illumination caused by the increased capacitance of the CdS thin film. The impedance measurements as well as photoluminescence data were consistent with an acceptor surface state model accounting for the depletion region of the CdS thin fim. Additionally the SLM is shown to exhibit photoelectrochemical cell characteristics such as dark rectification, and a photocurrent and photovoltage proportional to the illumination intensity. The SLM performance characteristics of good resolution and sensitivity is attributed to the surface state induced depletion region.