bluuebunny/crossref_metadata_2025 huggingface dataset:
Three-Dimensional Aerodynamic Design Optimization of a Turbine Blade by Using an Adjoint Method
Authors: Luo Jiaqi , Xiong Juntao , Liu Feng , McBean Ivan
Published: September 2010

This paper presents the application of an adjoint method to the aerodynamic design optimization of a turbine blade. With the adjoint method, the complete gradient information needed for optimization can be obtained by solving the governing flow equations and their corresponding adjoint equations only once, regardless of the number of design parameters. The formulations including imposition of appropriate boundary conditions for the adjoint equations of the Euler equations for turbomachinery problems are presented. Two design cases are demonstrated for a turbine cascade that involves a high tip flare, characteristic of steam turbine blading in low-pressure turbines. The results demonstrate that the design optimization method is effective and the redesigned blade yields weaker shock and compression waves in the supersonic region of the flow while satisfying the specified constraint. The relative effects of changing blade profile stagger, modifying the blade profile shape, and changing both stagger and profile shape at the same time are examined and compared. Navier–Stokes calculations are performed to confirm the performance at both the design and off-design conditions of the blade designed by the Euler method.
Transient Analysis of a Spring-Loaded Pressure Safety Valve Using Computational Fluid Dynamics (CFD)
Authors: Song Xue Guan , Wang Lin , Park Young Chul
Published: September 2010

A spring-loaded pressure safety valve (PSV) is a key device used to protect pressure vessels and systems. This paper developed a three-dimensional computational fluid dynamics (CFD) model in combination with a dynamics equation to study the fluid characteristics and dynamic behavior of a spring-loaded PSV. The CFD model, which includes unsteady analysis and a moving mesh technique, was developed to predict the flow field through the valve and calculate the flow force acting on the disk versus time. To overcome the limitation that the moving mesh technique in the commercial software program ANSYS CFX (Version 11.0, ANSYS, Inc., USA) cannot handle complex configurations in most applications, some novel techniques of mesh generation and modeling were used to ensure that the valve disk can move upward and downward successfully without negative mesh error. Subsequently, several constant inlet pressure loads were applied to the developed model. Response parameters, including the displacement of the disk, mass flow through the valve, and fluid force applied on the disk, were obtained and compared with the study of the behavior of the PSV under different overpressure conditions. In addition, the modeling approach could be useful for valve designers attempting to optimize spring-loaded PSVs.
HRSG Design for Integrated Reforming Combined Cycle With CO2 Capture
Authors: Nord Lars O. , Bolland Olav
Published: September 2010

This article illustrates aspects of heat recovery steam generator (HRSG) design when employing process integration in an integrated reforming combined cycle (IRCC) with precombustion CO2 capture. Specifically, the contribution of this paper is to show how heat integration in a precombustion CO2 capture plant impacts the selection of HRSG design. The purpose of such a plant is to generate power with very low CO2 emissions, typically below 100 g CO2/net kWh electricity. This should be compared with a state-of-the-art natural gas combined cycle (NGCC) plant with CO2 emissions around 380 g CO2/net kWh electricity. The design of the HRSG for the IRCC process was far from standard because of the significant amount of steam production from the heat generated by the autothermal reforming process. This externally generated steam was transferred to the HRSG superheaters and used in a steam turbine. For an NGCC plant, a triple-pressure reheat steam cycle would yield the highest net plant efficiency. However, when generating a significant amount of high-pressure steam external to the HRSG, the picture changed. The complexity of selecting an HRSG design increased when also considering that steam can be superheated and low-pressure and intermediate-pressure steam can be generated in the process heat exchangers. For the concepts studied, it was also of importance to maintain a high net plant efficiency when operating on natural gas. Therefore, the selection of HRSG design had to be a compromise between NGCC and IRCC operating modes.
High Temperature Fast Response Aerodynamic Probe
Authors: Lenherr Christian , Kalfas Anestis I. , Abhari Reza S.
Published: September 2010

In order to advance the technology for measurements in higher temperature flows, a novel miniature (diameter 2.5 mm) fast response probe that can be applied in flows with temperatures of up to 533 K (500°F) has been developed. The primary elements of the probe are two piezoresistive pressure transducers that are used to measure the unsteady pressure and unsteady velocity field, as well as the steady temperature. Additional temperature and strain gauge sensors are embedded in the shaft to allow a much higher degree of robustness in the use of this probe. The additional temperature sensor in the shaft is used to monitor and correct the heat flux through the probe shaft, facilitating thermal management of the probe. The strain gauge sensor is used to monitor and control probe shaft vibration. Entirely new packaging technology had to be developed to make possible the use of this probe at such high temperatures. Extensive calibration and thermal cycling of the probe used to bind the accuracy and the robustness of the probe. This novel probe is applied in the one-and-1/2-stage, unshrouded axial turbine at ETH Zurich; this turbine configuration is representative of a high work aero-engine. The flow conditioning stretch upstream of the first stator is equipped with a recently designed hot streak generator. Several parameters of the hot streak, including temperature, radial and circumferential position, and shape and size can be independently controlled. The interactions between the hot streak and the secondary flow present a perfect scenario to verify the probe’s capability to measure under real engine conditions. Therefore, measurements with the novel probe have been made in order to prove the principle and to detail the interaction effects with blade row pressure gradients and secondary flows.
Torsional Vibrations Caused by Geared Coupling in a Shaft Train Driven by a Steam Turbine
Authors: Pennacchi Paolo , Vania Andrea , Frattaroli Franco
Published: September 2010

Rotating machines that include geared shaft-trains can be affected by a dynamic behavior that is influenced by coupling effects between lateral and torsional vibrations. These latter vibrations are rarely measured by means of permanent probes in industrial machines; therefore, these phenomena can be often pointed out only by detecting abnormal harmonic components in the frequency spectrum of the lateral vibrations measured during common monitoring activities. Then, the diagnosis of the occurrence of coupling effects between torsional and lateral vibrations can be supported by the results provided by model-based techniques. In this paper, the results of the analysis of the dynamic behavior of a small power unit that was affected by abnormal lateral vibrations caused by the excitation of torsional normal modes of the geared shaft-train are shown and discussed.
Characterization of a Superheated Fuel Jet in a Crossflow
Authors: Corn May L. , Cohen Jeffrey M. , Lee Jerry C. , Hautman Donald J. , Thawley Scott M. , Brown Christopher T. , McDonell Vincent G.
Published: September 2010

An experiment was conducted to characterize a superheated fuel jet (Jet-A) injected into an unheated crossflow of air. The liquid phase of the fuel jet was characterized with high speed imaging and phase Doppler interferometry. The transition from a shear-atomized to a flash-atomized spray at a fuel temperature of 513 K (465°F) was observed at an ambient pressure of 1 atm, which is consistent with the bubble and dew point curves predicted for JP-8. The explosive breakup that was seen in the flash-atomized spray produced submicron droplets with a high radial momentum. This unique behavior makes superheated fuels an attractive design feature for fuel preparation devices that can employ flash boiling to enhance fuel atomization and mixing in a compact volume.
An Experimental Ignition Delay Study of Alkane Mixtures in Turbulent Flows at Elevated Pressures and Intermediate Temperatures
Authors: Beerer David , McDonell Vincent , Samuelsen Scott , Angello Leonard
Published: September 2010

Autoignition delay times of mixtures of alkanes and natural gas were studied experimentally in a high pressure and intermediate temperature turbulent flow reactor. Measurements were made at pressures between 7 atm and 15 atm and temperatures from 785 K to 935 K. The blends include binary and ternary mixtures of methane, ethane, and propane along with various natural gas blends. Based on these data, the effect of higher hydrocarbons on the ignition delay time of natural gas type fuels at actual gas turbine engine conditions has been quantified. While the addition of higher hydrocarbons in quantities of up to 30% was found to reduce the ignition delay by up to a factor of 4, the delay times were still found to be greater than 60 ms in all cases, which is well above the residence times of most engine premixers. The data were used to develop simple Arrhenius type correlations as a function of temperature, pressure, and fuel composition for design use.
A Reliability-Based Expression of ASME B&PV Code Equation (11) for Class 2 and 3 Nuclear Pipes
Authors: Avrithi Kleio , Ayyub Bilal M.
Published: September 2010

Previous research provided a reliability-based approach for the low-cycle fatigue design of Class 2 and 3 nuclear pipes. Reliability-based equations incorporate a threshold for the piping reliability and yield a safe and uniform design that moreover can be associated with the design risk. This brief discusses a direct reliability method to be used for Eq. (11) in Subparagraphs NC and ND-3653.2 of the ASME B&PV Code for Class 2 and 3 pipes, respectively. A computational example illustrates the developed methodology.
Surface texture and wetting stability of polydimethylsiloxane coated with aluminum oxide at low temperature by atomic layer deposition
Authors: Spagnola Joseph C. , Gong Bo , Parsons Gregory N.
Published: September 2010

The performance of polydimethylsiloxane (PDMS) elastomer in many of its applications, including surface molding and replication, microcontact lithography, and microfluidic device structures, is strongly influenced by its surface properties. While PDMS polymer is simple to use, the surface hydrophobicity and adsorptive properties of PDMS limit its functionality, for example, in aqueous microfluidic applications. Atomic layer deposition (ALD) is a low temperature vapor phase thin film coating technique that has recently been used to modify and encapsulate a wide range of polymer materials. In this work, the authors investigate reactions that proceed when PDMS polymer films are treated with cyclic gas exposure sequences commonly used to perform aluminum oxide ALD. Film growth is characterized by electron and infrared spectroscopy and by contact angle goniometry for a range of surface treatments and postdeposition air exposure times. The authors find that trimethylaluminum/water ALD can produce a smooth and uniform film coating on PDMS at 25–50 °C and that cracks become visible under optical microscopy for films >100 Å thick. At moderate temperatures, unique buckled surface textures appear in the deposited coating, which are ascribed to substrate thermal expansion effects. Aluminum oxide coatings on native PDMS, as well as on PDMS pretreated with UV ozone or oxygen plasma, show a hydrophilic surface condition immediately after deposition, but the surface becomes more hydrophobic after 24–48 h in ambient air or under inert gas storage, likely due to organic species out-diffusion through defects in the ALD coating. Infrared analysis is also used to identify consistent mechanisms associated with subsurface ALD nucleation on cast PDMS layers. These results provide valuable insight into a means to reliably modify the surface of PDMS using vapor phase precursor/surface reactions.
Molecular Mechanism of Calcium Channel Regulation in the Fight-or-Flight Response
Authors: Fuller Matthew D. , Emrick Michelle A. , Sadilek Martin , Scheuer Todd , Catterall William A.
Published: September 2010

Stimulation of cardiac Ca
2+
channel activity by PKA in the fight-or-flight response requires an autoinhibitory complex with the distal C-terminal domain and a kinase anchoring protein.
β-Adrenergic Regulation of the L-Type Ca
2+
Channel Ca
V
1.2 by PKA Rekindles Excitement
Authors: Hell Johannes W.
Published: September 2010

Modulation of cardiac Ca
2+
channels by protein kinase A in the fight-or-flight response involves their proteolytic processing and just the right amount of anchoring protein AKAP.
Sphingolipids: The Oil on the TRAFire That Promotes Inflammation
Authors: Napolitano Gennaro , Karin Michael
Published: September 2010

Lipid second messengers are required for signaling through tumor necrosis factor and Toll-like receptors.
Mutually Exclusive Genotypes for Pyrazinamide and 5-Chloropyrazinamide Resistance Reveal a Potential Resistance-Proofing Strategy
Authors: Baughn Anthony D. , Deng Jiaoyu , Vilchèze Catherine , Riestra Angelica , Welch John T. , Jacobs William R. , Zimhony Oren
Published: September 2010

The pyrazinamide (PZA) analog 5-chloropyrazinamide (5-Cl PZA) is active against mycobacterial species, including PZA-resistant strains of
Mycobacterium tuberculosis
. In
M. smegmatis
, overexpression of the type 1 fatty acid synthase (FAS I) confers resistance to 5-Cl PZA, a potent FAS I inhibitor. Since
M. tuberculosis
and
M. bovis
cannot tolerate FAS I overexpression, 5-Cl PZA resistance mutations have yet to be described for tubercle bacilli. In an attempt to identify other factors that govern the activity of 5-Cl PZA, we selected for 5-Cl PZA-resistant isolates from a library of transposon-mutagenized
M. smegmatis
isolates. Here, we report that increased expression of the
M. smegmatis
pyrazinamidase PzaA confers resistance to 5-Cl PZA and susceptibility to PZA in
M. smegmatis
,
M. tuberculosis
, and
M. bovis
. In contrast, while ectopic overexpression of the
M. tuberculosis
pyrazinamidase PncA increases PZA susceptibility, this amidase does not mediate resistance to 5-Cl PZA. We conclude that PncA-independent turnover of 5-Cl PZA represents a potential mechanism of resistance to this compound for
M. tuberculosis
, which will likely translate into enhanced PZA susceptibility. Thus, countersusceptibility can be manipulated as a resistance-proofing strategy for PZA-based compounds when these agents are used simultaneously.
Oritavancin Disrupts Membrane Integrity of
Staphylococcus aureus
and Vancomycin-Resistant Enterococci To Effect Rapid Bacterial Killing
Authors: Belley Adam , McKay Geoffrey A. , Arhin Francis F. , Sarmiento Ingrid , Beaulieu Sylvain , Fadhil Ibthihal , Parr Thomas R. , Moeck Gregory
Published: September 2010

Oritavancin is an investigational lipoglycopeptide in clinical development for the treatment of acute bacterial skin and skin structure infections. In this study, we demonstrate that oritavancin causes bacterial membrane depolarization and permeabilization leading to cell death of Gram-positive pathogens and that these effects are attributable to the 4′-chlorobiphenylmethyl group of the molecule.
Independent Behavior of Commensal Flora for Carriage of Fluoroquinolone-Resistant Bacteria in Patients at Admission
Authors: de Lastours Victoire , Chau Françoise , Tubach Florence , Pasquet Blandine , Ruppé Etienne , Fantin Bruno
Published: September 2010

The important role of commensal flora as a natural reservoir of bacterial resistance is now well established. However, whether the behavior of each commensal flora is similar to that of other floras in terms of rates of carriage and risk factors for bacterial resistance is unknown. During a 6-month period, we prospectively investigated colonization with fluoroquinolone-resistant bacteria in the three main commensal floras from hospitalized patients at admission, targeting
Escherichia coli
in the fecal flora, coagulase-negative
Staphylococcus
(CNS) in the nasal flora, and α-hemolytic streptococci in the pharyngeal flora. Resistant strains were detected on quinolone-containing selective agar. Clinical and epidemiological data were collected. A total of 555 patients were included. Carriage rates of resistance were 8.0% in
E. coli
, 30.3% in CNS for ciprofloxacin, and 27.2% in streptococci for levofloxacin; 56% of the patients carried resistance in at least one flora but only 0.9% simultaneously in all floras, which is no more than random. Risk factors associated with the carriage of fluoroquinolone-resistant strains differed between fecal
E. coli
(i.e., colonization by multidrug-resistant bacteria) and nasal CNS (i.e., age, coming from a health care facility, and previous antibiotic treatment with a fluoroquinolone) while no risk factors were identified for pharyngeal streptococci. Despite high rates of colonization with fluoroquinolone-resistant bacteria, each commensal flora behaved independently since simultaneous carriage of resistance in the three distinct floras was uncommon, and risk factors differed. Consequences of environmental selective pressures vary in each commensal flora according to its local specificities (clinical trial NCT00520715 [
http://clinicaltrials.gov/ct2/show/NCT00520715
]).
Uptake ofHelicobacter pyloriOuter Membrane Vesicles by Gastric Epithelial Cells
Authors: Parker Heather , Chitcholtan Kenny , Hampton Mark B. , Keenan Jacqueline I.
Published: September 2010

Helicobacter pyloribacteria colonize the human stomach where they stimulate a persistent inflammatory response.H. pyloriis considered noninvasive; however, lipopolysaccharide (LPS)-enriched outer membrane vesicles (OMV), continuously shed from the surface of this bacterium, are observed within gastric epithelial cells. The mechanism of vesicle uptake is poorly understood, and this study was undertaken to examine the roles of bacterial VacA cytotoxin and LPS in OMV binding and cholesterol and clathrin-mediated endocytosis in vesicle uptake by gastric epithelial cells. OMV association was examined using a fluorescent membrane dye to label OMV, and a comparison was made between the associations of vesicles from a VacA+strain and OMV from a VacA−isogenic mutant strain. Within 20 min, essentially all associated OMV were intracellular, and vesicle binding appeared to be facilitated by the presence of VacA cytotoxin. Uptake of vesicles from the VacA+strain was inhibited byH. pyloriLPS (58% inhibition with 50 μg/ml LPS), while uptake of OMV from the VacA−mutant strain was less affected (25% inhibition with 50 μg/ml LPS). Vesicle uptake did not require cholesterol. However, uptake of OMV from the VacA−mutant strain was inhibited by a reduction in clathrin-mediated endocytosis (42% with 15 μg/ml chlorpromazine), while uptake of OMV from the VacA+strain was less affected (25% inhibition with 15 μg/ml chlorpromazine). We conclude that VacA toxin enhances the association ofH. pyloriOMV with cells and that the presence of the toxin may allow vesicles to exploit more than one pathway of internalization.
Listeria monocytogenes
Uses Listeria Adhesion Protein (LAP) To Promote Bacterial Transepithelial Translocation and Induces Expression of LAP Receptor Hsp60
Authors: Burkholder Kristin M. , Bhunia Arun K.
Published: September 2010

Listeria monocytogenes
interaction with the intestinal epithelium is a key step in the infection process. We demonstrated that
Listeria
adhesion protein (LAP) promotes adhesion to intestinal epithelial cells and facilitates extraintestinal dissemination
in vivo
. The LAP receptor is a stress response protein, Hsp60, but the precise role for the LAP-Hsp60 interaction during
Listeria
infection is unknown. Here we investigated the influence of physiological stressors and
Listeria
infection on host Hsp60 expression and LAP-mediated bacterial adhesion, invasion, and transepithelial translocation in an enterocyte-like Caco-2 cell model. Stressors such as heat (41°C), tumor necrosis factor alpha (TNF-α) (100 U), and
L. monocytogenes
infection (10
4
to 10
6
CFU/ml) significantly (
P
< 0.05) increased plasma membrane and intracellular Hsp60 levels in Caco-2 cells and consequently enhanced LAP-mediated
L. monocytogenes
adhesion but not invasion of Caco-2 cells. In transepithelial translocation experiments, the wild type (WT) exhibited 2.7-fold more translocation through Caco-2 monolayers than a
lap
mutant, suggesting that LAP is involved in transepithelial translocation, potentially via a paracellular route. Short hairpin RNA (shRNA) suppression of Hsp60 in Caco-2 cells reduced WT adhesion and translocation 4.5- and 3-fold, respectively, while adhesion remained unchanged for the
lap
mutant. Conversely, overexpression of Hsp60 in Caco-2 cells enhanced WT adhesion and transepithelial translocation, but not those of the
lap
mutant. Furthermore, initial infection with a low dosage (10
6
CFU/ml) of
L. monocytogenes
increased plasma membrane and intracellular expression of Hsp60 significantly, which rendered Caco-2 cells more susceptible to subsequent LAP-mediated adhesion and translocation. These data provide insight into the role of LAP as a virulence factor during intestinal epithelial infection and pose new questions regarding the dynamics between the host stress response and pathogen infection.
The Coupling Protein Cagβ and Its Interaction Partner CagZ Are Required for Type IV Secretion of the
Helicobacter pylori
CagA Protein
Authors: Jurik Angela , Haußer Elisabeth , Kutter Stefan , Pattis Isabelle , Praßl Sandra , Weiss Evelyn , Fischer Wolfgang
Published: September 2010

Bacterial type IV secretion systems are macromolecule transporters with essential functions for horizontal gene transfer and for symbiotic and pathogenic interactions with eukaryotic host cells.
Helicobacter pylori
, the causative agent of type B gastritis, peptic ulcers, gastric adenocarcinoma, and mucosa-associated lymphoid tissue (MALT) lymphoma, uses the Cag type IV secretion system to inject its effector protein CagA into gastric cells. This protein translocation results in altered host cell gene expression profiles and cytoskeletal rearrangements, and it has been linked to cancer development. Interactions of CagA with host cell proteins have been studied in great detail, but little is known about the molecular details of CagA recognition as a type IV secretion substrate or of the translocation process. Apart from components of the secretion apparatus, we previously identified several CagA translocation factors that are either required for or support CagA translocation. To identify protein-protein interactions between these translocation factors, we used a yeast two-hybrid approach comprising all
cag
pathogenicity island genes. Among several other interactions involving translocation factors, we found a strong interaction between the coupling protein homologue Cagβ (HP0524) and the Cag-specific translocation factor CagZ (HP0526). We show that CagZ has a stabilizing effect on Cagβ, and we demonstrate protein-protein interactions between the cytoplasmic part of Cagβ and CagA and between CagZ and Cagβ, using immunoprecipitation and pull-down assays. Together, our data suggest that these interactions represent a substrate-translocation factor complex at the bacterial cytoplasmic membrane.
Surface Immunolabeling and Consensus Computational Framework To Identify Candidate Rare Outer Membrane Proteins ofTreponema pallidum
Authors: Cox David L. , Luthra Amit , Dunham-Ems Star , Desrosiers Daniel C. , Salazar Juan C. , Caimano Melissa J. , Radolf Justin D.
Published: September 2010

Treponema pallidumreacts poorly with the antibodies present in rabbit and human syphilitic sera, a property attributed to the paucity of proteins in its outer membrane. To better understand the basis for the syphilis spirochete's “stealth pathogenicity,” we used a dual-label, 3-step amplified assay in which treponemes encapsulated in gel microdroplets were probed with syphilitic sera in parallel with anti-FlaA antibodies. A small (approximately 5 to 10%) but reproducible fraction of intact treponemes bound IgG and/or IgM antibodies. Three lines of evidence supported the notion that the surface antigens were likely β-barrel-forming outer membrane proteins (OMPs): (i) surface labeling with anti-lipoidal (VDRL) antibodies was not observed, (ii) immunoblot analysis confirmed prior results showing thatT. pallidumglycolipids are not immunoreactive, and (iii) labeling of intact organisms was not appreciably affected by proteinase K (PK) treatment. With this method, we also demonstrate that TprK (TP0897), an extensively studied candidate OMP, and TP0136, a lipoprotein recently reported to be surface exposed, are both periplasmic. Consistent with the immunolabeling studies, TprK was also found to lack amphiphilicity, a characteristic property of β-barrel-forming proteins. Using a consensus computational framework that combined subcellular localization and β-barrel structural prediction tools, we generated ranked groups of candidate rare OMPs, the predictedT. pallidumouter membrane proteome (OMPeome), which we postulate includes the surface-exposed molecules detected by our enhanced gel microdroplet assay. In addition to underscoring the syphilis spirochete's remarkably poor surface antigenicity, our findings help to explain the complex and shifting balance between pathogen and host defenses that characterizes syphilitic infection.
Immunohistochemical assessment of respiratory viruses in necropsy samples from lethal non-pandemic seasonal respiratory infections
Authors: do Carmo Debur Maria , Raboni Sonia Mara , Flizikowski Fabiane B Z , Chong Débora C , Persicote Ana Paula , Nogueira Meri B , Rosele Luine V , de Almeida Sergio Monteiro , de Noronha Lucia
Published: September 2010

Background/aim

Acute respiratory infections are an important cause of childhood morbidity and mortality throughout the world, and viruses have often been reported to be an aetiological agent. This study aimed to identify respiratory viruses in paraffin-embedded samples of paediatric lung necropsy specimens, using immunohistochemistry on tissue microarray slides.

Methods

Retrospective study in 200 lung tissue samples from children who had died from severe respiratory infections during 1985–2005. Immunoperoxidase assay was performed to detect the viruses that were most commonly associated with respiratory tract infections: influenza virus A (FLU A), influenza virus B (FLU B), respiratory syncytial virus (RSV), adenovirus (AdV) and parainfluenza virus (PIV) types 1, 2 and 3.

Results

Viruses were detected in 71 (35.5%) cases. Most positive cases were observed in children younger than 6 months. In 42.3% of cases, only one virus was detected: 11 (36.7%) RSV; 7 (23.3%) AdV; 4 (13.3%) PIV2; 3 (10%) FLU A; 2 (6.7%) FLU B; 2 (6.7%) PIV3; and 1 (3.3%) PIV1. Co-infection with more than one virus was observed in 41 (57.7%) cases. No positive correlations were observed between the presence of viral antigens and seasonality of the infection, sex, age or histopathological findings.

Conclusions

Non-pandemic seasonal respiratory viruses are involved in a significant number of deaths in paediatric patients; these findings highlight the importance of laboratory investigation of these agents in patients hospitalised with severe acute respiratory infections.
Basaloid squamous cell carcinoma of the head and neck: role of HPV and implication in treatment and prognosis
Authors: Thariat J , Badoual C , Faure C , Butori C , Marcy P Y , Righini C A
Published: September 2010

Basaloid squamous cell carcinoma (BSCC) is a rare variant of squamous cell carcinoma (SCC) of the head and neck. Wain's criteria (peripheral palisading, association with SCC, high nuclear-cytoplasmic ratio, high mitotic rate, solid growth), anti-34BE12 and CK 5/6 staining, and absence of neuroendocrine markers are mandatory for the diagnosis of BSCC. Its increasing incidence parallels that of human papilloma virus (HPV)-positive tumours for the oropharyngeal subsite. On the other hand, BSCC is frequently considered a high-grade carcinoma of poorer prognosis than its SCC counterparts, mostly due to a higher rate of distant metastases. However, BSCC has similar or better locoregional control rates and a relatively better radiosensitivity than SCC. BSCC seems to have a dual behaviour depending, at least partly, on its recently described association with HPV. The basaloid subtype of SCC, owing to its particular behaviour, should be systematically investigated along with HPV and smoking status, as those factors may be determinant in the response to treatment.
Assessment of malignant potential of oral submucous fibrosis through evaluation of p63, E-cadherin and CD105 expression
Authors: Das Raunak Kumar , Pal Mousumi , Barui Ananya , Paul Ranjan Rashmi , Chakraborty Chandan , Ray Ajoy Kumar , Sengupta Sanghamitra , Chatterjee Jyotirmoy
Published: September 2010

Background

The assessment of malignant potential of oral submucous fibrosis grades vis-à-vis their progression towards malignancy is associated with expression of possible multiple molecular markers.

Aims

To analyse p63, E-cadherin and CD105 expression in this premalignant pathosis with a view to unravel and understand the expression of these molecules as markers.

Methods

The oral mucosal biopsies (normal, oral submucous fibrosis with and without dysplasia) were studied with routine H&E, and by immunohistochemistry for p63, E-cadherin and CD105 expression. p63 was assessed as percentage of positive nuclei. E-cadherin expression was estimated through (i) distance between basement membrane and E-cadherin expression initiation point, (ii) ratio between epithelial thickness and epithelial thickness displaying E-cadherin, and (iii) E-cadherin intensity variation along the expression path. CD105 expression was assessed qualitatively.

Results

The p63+ cells were highest in severely dysplastic tissues followed by other dysplastic grades, normal oral mucosa and non-dysplastic conditions. However, the p63+ cells displayed the feature of progressive maturation only in normal mucosa. There was a loss of membranous E-cadherin in basal layers of all diseased conditions; it was highest in severe dysplasia. There was significant variation (p<0.0001) in E-cadherin intensity within and between the tissues (normal and diseased). CD105 expression increased abruptly in dysplasia.

Conclusions

The malignant potential of this pre-cancerous condition is likely to be correlated with an increase in p63 and CD105 expression and a concomitant loss of membranous E-cadherin. This may lead to marker identification through greater validation.
New double embedding technique for specimens of endoscopic submucosal dissection using agarose: comparison with other media
Authors: Zozumi Masataka , Nakai Mayumi , Ito Takashi , Matsuda Ikuo , Hao Hiroyuki , Tsukamoto Yoshitane , Hirota Seiichi
Published: September 2010

Aims

Procedure of endoscopic submucosal dissection (ESD) has been introduced widely for treatment of early gastric cancers. For such specimens, accurate pathological diagnosis, especially concerning depth of the invasion and exposure to margins, is essential to decide on the necessity of additional treatment. Therefore, easy and reliable tissue-processing method for multiple cut specimens is needed. The authors report here a new double embedding technique for specimens of ESD.

Methods

Formalin-fixed whole specimen was superficially wrapped by agarose (the first embedding), and the tissue-agarose block was cut at 2–3 mm intervals. Each cut specimen was laid down with 90° rotation. This procedure permitted ‘on edge’ embedding of thin tissues in paraffin (the second embedding) and subsequent preparation of perpendicular section to the tissue surface. The authors compared the handleability and stainability among several media including various types of agar, agarose and gelatin for first embedding. A survey by questionnaire was carried out on handleability and/or impression on various tissue-processing steps from pathology technicians.

Results

Among the media examined, agarose showed the best solubility in water and the best transparency on several representative stainings. According to the survey, pathology technicians seemed to feel that the present method was better than the usual tissue processing method, especially in shortened time consumption and accuracy of alignment of multiple tissues for ESD specimens.

Conclusions

The present new double embedding technique using agarose provides not only an easy and reliable embedding procedure for technicians but also accurate and exact diagnosis for pathologists.
Virtual microscopy for histology quality assurance of screen-detected polyps
Authors: Risio Mauro , Bussolati Gianni , Senore Carlo , Vigna Stefano , Frangipane Elena , Segnan Nereo , Cassoni Paola
Published: September 2010

Aim

Histology quality assurance is crucial for screening programmes and can be performed by circulating glass slides, which has certain intrinsic disadvantages. The present study aimed to assess the accuracy of virtual microscopy in terms of reliability and diagnostic reproducibility in colorectal cancer screening programmes.

Methods

457 consecutive lesions detected in people undergoing colonoscopy were examined histologically in two pathology units, using both traditional optical microscopy and virtual microscopy (6–12 months later). Intra- and inter-observer agreement using the two approaches was determined using κ statistics.

Results

Intra- and inter-observer agreements were substantially unmodified by the use of the virtual microscopy approach compared with traditional optical microscopy; moreover, for some histological features critical for patient management in colorectal cancer screening programmes (such as the presence of a villous component within the adenoma), virtual microscopy increased interobserver agreement (κ statistics 0.66 versus 0.52).

Conclusions

This study shows that virtual microscopy can be an effective tool for diagnostic quality assurance in colorectal cancer screening programmes, and its accuracy is equivalent to or higher than that of optical microscopy in the validation of histological criteria (eg, advanced adenoma) crucial for patient management in screening programmes.
Surveillance of mesothelioma and workers' compensation in British Columbia, Canada
Authors: Kirkham Tracy L , Koehoorn Mieke W , McLeod Christopher B , Demers Paul A
Published: September 2010

Objectives

To determine the rate of workers' compensation for mesothelioma cases in the Canadian province of British Columbia, examine trends in mesothelioma cases and compensation over time, and identify factors associated with compensation status for mesothelioma cases.

Methods

Mesothelioma cases in the provincial cancer registry were linked at the individual level with accepted claims for mesothelioma in the provincial workers' compensation system for the period 1970–2005.

Results

391 of the 485 workers' compensated claims were linked (81% match rate) with a record in the cancer registry for an overall mesothelioma compensation rate of 33% over the study period and a high of 49% in the last 5 years. Compensation rates were lower for women, older (retired) as well as younger workers, and sites other than the pleura.

Conclusions

Although the workers' compensation rate for mesothelioma increased over time, the rate was much lower than anticipated for cases believed to be work-related cancers. Several key factors may significantly influence awareness by clinicians and workers of the work-relatedness of mesothelioma and of workers' compensation benefits. Regulatory agencies need to develop policies or effective notification systems to ensure that all newly diagnosed mesothelioma cases seek compensation benefits.
Comparison of exposure assessment methods for occupational carcinogens in a multi-centre lung cancer case–control study
Authors: Peters Susan , Vermeulen Roel , Cassidy Adrian , Mannetje Andrea 't , van Tongeren Martie , Boffetta Paolo , Straif Kurt , Kromhout Hans ,   on behalf of the INCO Group
Published: September 2010

Objectives

Retrospective exposure assessment remains a problematic aspect of population-based case–control studies. Different methods have been developed, including case-by-case expert assessment and job–exposure matrices (JEM). The present analyses compare exposure prevalence and risk estimates derived by different exposure assessment methods.

Methods

In the context of a case–control study conducted in seven European countries, exposure was estimated for asbestos, diesel motor emissions (DME) and crystalline silica, using three different assessment methods. First, experts assigned exposures to all reported jobs on a case-by-case basis. Second, a population-specific JEM (PSJEM) was developed using the expert assessments of controls only, and re-applied to all study subjects. Third, an independent general population JEM (GPJEM) was created by occupational exposure experts not involved in the original study, and applied to study subjects. Results from these methods were compared.

Results

There was poor to fair agreement in assigned exposure between expert assessment and the GPJEM (kappas: asbestos 0.17; DME 0.48; silica 0.38). Exposure prevalence was significantly heterogeneous (p<0.01) between countries for all three agents and assessment methods. For asbestos and DME, significant country heterogeneity in risk estimates was observed when using expert assessment. When applying the GPJEM, the heterogeneity in risk estimates for asbestos and, to some extent, silica diminished.

Conclusions

It has been previously advocated that the expert assessment approach to assign exposures based on detailed questionnaire responses provides more accurate exposure estimates than JEM-based results. However, current results demonstrated little, if any, advantage of case-by-case assessment when compared to a JEM approach.
Prevalence of smuggled and foreign cigarette use in Tehran, 2009
Authors: Heydari Gholamreza , Tafti Saeid Fallah , Telischi Firouzeh , Joossens Luk , Hosseini Mostafa , Masjedi Mohammadreza , Ghafari Mostafa
Published: September 2010

Background

Iran is one of two main target markets for tobacco smuggling in the WHO's Eastern Mediterranean Region. The Iranian government has a local tobacco monopoly but there is high demand for international brands. Informal reports show about 20% of cigarette consumption is smuggled brands. This pack survey study is the first in Iran to gather validated information on use of smuggled cigarettes.

Methods

A randomized cross-sectional household survey in Tehran in 2008–2009 of 1540 smokers aged 16–90 (83% men) was performed, including interviewer checking of cigarette packs.

Results

In all, 20.9% of cigarettes and 6.7% of domestic branded cigarettes were smuggled. A total of 60.1% of smokers preferred foreign cigarettes. There was no significant difference between consumption of illegal cigarettes by sex. (Fisher exact test p=0.61) Use of smuggled cigarettes was higher among younger smokers (p=0.01)

Conclusions

Use of illegal cigarettes is high. Tobacco control laws outlawing their sale are not being enforced.
Adfreeze strength of model piles in ice
Authors: Parameswaran V. R.
Published: September 2010

The adfreeze bond strengths of wood, concrete, and steel H-section piles embedded in fresh-water ice have been measured under constant rates of displacement for displacement rates varying between 10−4 and 10−1 mm/min (loading rates between 10−3 and 10 kN/min). Wood piles showed the highest adfreeze strength (0.6 and 1.8 MPa); that for concrete piles was independent of rate of displacement (average value 0.8 MPa); that for steel H-sections varied between 0.2 and 0.6 MPa. These results were used in estimating the contribution of ice adhesion to the total adfreeze strength of various piles in frozen sand.
Riverbank instability and development control in Saskatoon
Authors: Clifton A. W. , Krahn J. , Fredlund D. G.
Published: September 2010

Slope instability along the banks of the South Saskatchewan River Valley has been a continual problem for Saskatoon's City Engineering Department since 1913. It has affected building and bridge foundations, damaged municipal roads and services, and interfered with park and playground development. Where the glacial till in the banks is overlain by lacustrine clays, silts, and sands, the lower portion of the slip surface invariably follows the stratigraphic contact between the till and the overlying materials. Piping of intertill stratified drift is the major cause of slope instability where the till is exposed at the surface. Groundwater from the natural infiltration and from lawn watering greatly affects the slope stability. Remedial techniques have consisted primarily of subsurface drainage systems.Increased pressure for development along the riverbank has led to the recent establishment of the Meewasin Valley Authority which has complete control of development within and along the river valley. Opposition to the Authority's establishment has been strong. Its success in controlling development near unstable slopes will only be proven with time.
On the computation of parameters that model snow avalanche motion
Authors: Bakkehøi S. , Cheng T. , Domaas U. , Lied K. , Perla R. , Schieldrop B.
Published: September 2010

This paper explores the computational problem of finding suitable numbers to use in a two-parameter model of snow avalanche dynamics. The two parameters are friction, μ, and a ratio of avalanche mass to drag, M/D. Given a path profile, and a maximum avalanche speed, then it is possible to compute unique values for u and M/D. If only the path profile and the stopping position are known, then it is possible to compute tables of pairs {μ, M/D} which can be tested as predictors of avalanche speeds. To generate these tables it is convenient to scale M/D in multiples of the total vertical drop of the path. The computations were tested on 136 avalanche paths. Values of {μ, M/D} were stratified, and certain values were rejected as unrealistic.
Charts for the design and evaluation of simple earth slopes using total and partial factors of safety: a review of several available methods
Authors: Baikie L. D.
Published: September 2010

A review of several available stability chart solutions for simple earth slopes was undertaken to assess their suitability for use with partial safety factors. The [Formula: see text] charts and Casagrande resistance envelopes were found to be particularly suited to the use of such factors and for comparing this approach with the traditional practice of using total safety factors. Casagrande resistance envelopes and factor of safety charts are presented for a range in slope inclinations. Key words: earth slopes, stability charts, total safety factors, partial safety factors, Casagrande resistance envelopes.
Model studies on the stability of confined fills
Authors: Mitchell R. J.
Published: September 2010

Stabilized backfills are used extensively for ground control in most bulk underground mining operations. The stability of the fill face during pillar ore removal is of prime concern and has been the subject of considerable research because of many factors, including the effects of wall interaction and the high costs of stabilization. Centrifuge modelling data presented in this paper clearly show that fill confined between sloped walls, which is the most common prototype condition, is much more stable than fill between vertical rock walls, a condition previously studied. This study also shows that wall roughness contributes substantially to the fill stability and that current design criteria are quite conservative. Data from stress transducers, mounted on centrifuge strongboxes to monitor stress changes on the fill boundaries during gravitational stress simulations, show that fill arching and wall shear effects are responsible for the improved stability of confined fills. Key words: mine backfill, stability, lateral stresses, arching, centrifuge model, fill geometry.
Application of hydraulic gradient similitude method to small-scale footing tests on sand
Authors: Yan Li , Byrne Peter M.
Published: September 2010

A series of model footing tests is presented. The hydraulic gradient similitude method is used to increase the self-weight stress in the model tests. The testing principle, apparatus, and test procedures are described in detail. The model scaling laws implied by the hydraulic gradient similitude method are verified from the experimental results using the technique "modelling of models." Test results are compared with centrifuge tests and finite element analyses. It is found that the test results are consistent with the observations from centrifuge tests. Finite element predictions using the soil parameters obtained from conventional triaxial tests are found to be in remarkably good agreement with the model test results. Key words: model tests, footings, sand.
Load–displacement behaviour of socketed piers—Hamilton General Hospital
Authors: Horvath Robert G. , Schebesch Daniel , Anderson Murray
Published: September 2010

Monitoring the settlement behaviour of full-scale drilled pier foundation that are in service is seldom possible. This report describes the instrumentation and monitoring program for three of the drilled pier foundations socketed into weak shale used for the Hamilton General Hospital addition, and presents and summarizes the data collected over a period of almost 2 years.The three socketed piers were constructed so that each had different load support conditions. Pier P5 was conventional, and supported loads through shaft resistance in the soil and rock and end bearing in the rock. Pier K3 was similar except shaft resistance in the soil was eliminated by installing a sonotube casing in the upper portion of the shaft. Pier P3, which also had a sonotube casing, was constructed with a void apparatus at the base to eliminate end bearing resistance so that support was achieved only through shaft resistance in the rock socket.Instrumentation included multiple-point rod extensometers, with remote readout, to measure vertical displacements at the top of the pier, top of the rock, and bottom of the socket. Load cells, reinforcing bar load cells, and concrete embedment strain gauges were also installed in an attempt to determine load distribution in the pier foundations.Under approximately full dead loading, less than 3 mm (1/8 in.) settlement has been observed. The settlement and bottom load cell data suggest that very little of the applied loading (less than 5%) has been transferred to the base of the socket. Key words: rock-socketed piers, settlement, load transfer, weak shale, instrumentation, monitoring, full-scale foundations.
CONTROL AND STABILIZATION OF THE NONLINEAR SCHRÖDINGER EQUATION ON RECTANGLES
Authors: ROSIER LIONEL , ZHANG BING-YU
Published: September 2010

This paper studies the local exact controllability and the local stabilization of the semilinear Schrödinger equation posed on a product of n intervals (n ≥ 1). Both internal and boundary controls are considered, and the results are given with periodic (resp. Dirichlet or Neumann) boundary conditions. In the case of internal control, we obtain local controllability results which are sharp as far as the localization of the control region and the smoothness of the state space are concerned. It is also proved that for the linear Schrödinger equation with Dirichlet control, the exact controllability holds in H-1(Ω) whenever the control region contains a neighborhood of a vertex.