bluuebunny/crossref_metadata_2025 huggingface dataset:
A Simple Parametric Model for the Analysis of Cooled Gas Turbines
Authors: Gülen S. Can
Published: September 2010

A natural gas fired gas turbine combined cycle power plant is the most efficient option for fossil fuel based electric power generation that is commercially available. Trade publications report that currently available technology is rated near 60% thermal efficiency. Research and development efforts are in place targeting even higher efficiencies in the next two decades. In the face of diminishing natural resources and increasing carbon dioxide emissions, leading to greenhouse gas effect and global warming, these efforts are even more critical today than in the last century. The main performance driver in a combined cycle power plant is the gas turbine. The basic thermodynamics of the gas turbine, described by the well-known Brayton cycle, dictates that the key design parameters that determine the gas turbine performance are the cycle pressure ratio and maximum cycle temperature at the turbine inlet. While performance calculations for an ideal gas turbine are straightforward with compact mathematical formulations, detailed engineering analysis of real machines with turbine hot gas path cooling requires complex models. Such models, requisite for detailed engineering design work, involve highly empirical heat transfer formulations embedded in a complex system of equations that are amenable only to numerical solutions. A cooled turbine modeling system incorporating all pertinent physical phenomena into compact formulations is developed and presented in this paper. The model is fully physics-based and amenable to simple spreadsheet calculations while illustrating the basic principles with sufficient accuracy and extreme qualitative rigor. This model is valuable not only as a teaching and training tool, it is also suitable to preliminary gas turbine combined cycle design calculations in narrowing down the field of feasible design options.
Application of Silicon Carbide Photodiode Flame Temperature Sensors in an Active Combustion Pattern Factor Control System
Authors: Palmer Carl A. , Abel Royce L. , Sandvik Peter
Published: September 2010

This paper describes the development and initial application studies for an active combustion pattern factor controller (APFC) for gas turbines. The system is based around the use of a novel silicon carbide optical ultraviolet dual diode flame temperature sensor (FTS) developed by General Electric Co. The APFC system determines combustion flame temperatures, validates the values, and integrates an assessment of signal and combustion hardware health to determine how to trim the fuel flow to individual fuel nozzles. Key aspects of the system include the following: determination of each flame’s bulk temperature using the FTS, assessment of the reliability of the flame temperature data and physical combustion hardware health through analysis of the high-frequency output of the sensor, validation of the flame temperature signal using a data-driven approach, fusion of sensor “health indices” into the APFC to alter the trim control signal based on the health (or “believability”) of each sensor and fuel nozzle/combustor, fault-tolerant peak/valley detection and control module that selects individual fuel valves to target for reducing pattern factor while simultaneously balancing the overall fuel flow. The authors demonstrated feasibility of the approach by performing simulations using a quasi-2D T700 turbine engine model. Tests were run on the simulated platform with no faults, simulated sensor faults, and on a system with underlying combustion hardware issues. The final APFC system would be applicable for aviation, naval, and land-based commercial gas turbines, and can be used in closed-loop control or adapted as an open-loop advisory/diagnostic system.
Assessment of Future Aero-engine Designs With Intercooled and Intercooled Recuperated Cores
Authors: Kyprianidis Konstantinos G. , Grönstedt Tomas , Ogaji S. O. T. , Pilidis P. , Singh R.
Published: September 2010

Reduction in CO2 emissions is strongly linked with the improvement of engine specific fuel consumption, as well as the reduction in engine nacelle drag and weight. Conventional turbofan designs, however, that reduce CO2 emissions—such as increased overall pressure ratio designs—can increase the production of NOx emissions. In the present work, funded by the European Framework 6 collaborative project NEW Aero engine Core concepts (NEWAC), an aero-engine multidisciplinary design tool, Techno-economic, Environmental, and Risk Assessment for 2020 (TERA2020), has been utilized to study the potential benefits from introducing heat-exchanged cores in future turbofan engine designs. The tool comprises of various modules covering a wide range of disciplines: engine performance, engine aerodynamic and mechanical design, aircraft design and performance, emissions prediction and environmental impact, engine and airframe noise, as well as production, maintenance and direct operating costs. Fundamental performance differences between heat-exchanged cores and a conventional core are discussed and quantified. Cycle limitations imposed by mechanical considerations, operational limitations and emissions legislation are also discussed. The research work presented in this paper concludes with a full assessment at aircraft system level that reveals the significant potential performance benefits for the intercooled and intercooled recuperated cycles. An intercooled core can be designed for a significantly higher overall pressure ratio and with reduced cooling air requirements, providing a higher thermal efficiency than could otherwise be practically achieved with a conventional core. Variable geometry can be implemented to optimize the use of the intercooler for a given flight mission. An intercooled recuperated core can provide high thermal efficiency at low overall pressure ratio values and also benefit significantly from the introduction of a variable geometry low pressure turbine. The necessity of introducing novel lean-burn combustion technology to reduce NOx emissions at cruise as well as for the landing and take-off cycle, is demonstrated for both heat-exchanged cores and conventional designs. Significant benefits in terms of NOx reduction are predicted from the introduction of a variable geometry low pressure turbine in an intercooled core with lean-burn combustion technology.
Experiments on Flame Flashback in a Quasi-2D Turbulent Wall Boundary Layer for Premixed Methane-Hydrogen-Air Mixtures
Authors: Eichler Christian , Sattelmayer Thomas
Published: September 2010

Premixed combustion of hydrogen-rich mixtures involves the risk of flame flashback through wall boundary layers. For laminar flow conditions, the flashback mechanism is well understood and is usually correlated by a critical velocity gradient at the wall. Turbulent transport inside the boundary layer considerably increases the flashback propensity. Only tube burner setups were investigated in the past, and thus turbulent flashback limits were only derived for a fully developed Blasius wall friction profile. For turbulent flows, details of the flame propagation in proximity to the wall remain unclear. This paper presents results from a new experimental combustion rig, apt for detailed optical investigations of flame flashbacks in a turbulent wall boundary layer developing on a flat plate and being subject to an adjustable pressure gradient. Turbulent flashback limits are derived from the observed flame position inside the measurement section. The fuels investigated cover mixtures of methane, hydrogen, and air at various mixing ratios. The associated wall friction distributions are determined by Reynolds-averaged Navier-Stokes (RANS) computations of the flow inside the measurement section with fully resolved boundary layers. Consequently, the interaction between flame back pressure and incoming flow is not taken into account explicitly, in accordance with the evaluation procedure used for tube burner experiments. The results are compared with literature values, and the critical gradient concept is reviewed in light of the new data.
A Methodology for On the Fly Acoustic Characterization of the Feeding Line Impedances in a Turbulent Swirled Combustor
Authors: Lamraoui A. , Richecoeur F. , Schuller T. , Ducruix S.
Published: September 2010

A methodology is proposed to determine on the fly the acoustic impedances at the boundaries of a combustor under operation and without the need for an external forcing device. The methodology is applied hereby to obtain the reflection coefficients of the air and fuel feeding lines supplying a swirled combustor operating in lean conditions and featuring an unstable regime. It is based on a three-microphone technique and uses the combustion roar noise inside the chamber to get estimates of the boundary impedances in the low frequency limit. Conditions under which this method yields reliable results for the reflection coefficient are examined, and a criterion based on the coherence between microphone signals is proposed to determine the frequency bandwidth for impedance reconstruction. The method also takes into account the flow Mach number in the supplying pipes, which can be non-negligible because of their reduced diameter. The technique is validated against data obtained in a dedicated impedance measurement setup equipped with a high-efficiency loudspeaker.
Evolutionary Optimization of Micro-Thrust Bearings With Periodic Partial Trapezoidal Surface Texturing
Authors: Papadopoulos Christos I. , Nikolakopoulos Pantelis G. , Kaiktsis Lambros
Published: September 2010

An optimization study of trapezoidal surface texturing in slider micro-bearings, via computational fluid dynamics (CFD), is presented. The bearings are modeled as micro-channels, consisting of a moving and a stationary wall. The moving wall (rotor) is assumed smooth, while part of the stationary wall (stator) exhibits periodic dimples of trapezoidal form. The extent of the textured part of the stator and the dimple geometry are defined parametrically; thus, a wide range of texturing configurations is considered. Flow simulations are based on the numerical solution of the Navier–Stokes equations for incompressible isothermal flow. To optimize the bearing performance, an optimization problem is formulated and solved by coupling the CFD code with an optimization tool based on genetic algorithms and local search methods. Here, the design variables define the bearing geometry, while load carrying capacity is the objective function to be maximized. Optimized texturing geometries are obtained for the case of parallel bearings for several numbers of dimples, illustrating significant load carrying capacity levels. Further, these optimized texturing patterns are applied to converging bearings for different convergence ratio values; the results demonstrate that, for small and moderate convergence ratios, a substantial increase in load carrying capacity, in comparison to smooth bearings, is obtained. Finally, an optimization study performed at a high convergence ratio shows that, in comparison to the parallel slider, the optimal texturing geometry is substantially different, and that performance improvement over smooth bearings is possible even for steep sliders.
Influence of the Primary Jets and Fuel Injection on the Aerodynamics of a Prototype Annular Gas Turbine Combustor Sector
Authors: Mohammad Bassam , Jeng San-Mou , Andac M. Gurhan
Published: September 2010

Transverse dilution jets are widely used in combustion systems. The current research provides a detailed study of the primary jets of a realistic annular combustion chamber sector. The combustor sector comprises an aerodynamic diffuser, inlet cowl, combustion dome, primary dilution jets, secondary dilution jets, and cooling strips to provide convective cooling to the liner. The chamber contracts toward the end to fit the turbine nozzle ring. 2D PIV is employed at an atmospheric pressure drop of 4% (isothermal) to delineate the flow field characteristics. The laser is introduced to the sector through the exit flange. The interaction between the primary jets and the swirling flow as well as the sensitivity of the primary jets to perturbations is discussed. The perturbation study includes: effect of partially blocking the jets, one at a time, the effect of blocking the convective cooling holes, placed underneath the primary jets and shooting perpendicular to it. In addition, the effect of reducing the size of the primary jets as well as off-centering the primary jets is explained. Moreover, PIV is employed to study the flow field with and without fuel injection at four different fuel flow rates. The results show that the flow field is very sensitive to perturbations. The cooling air interacts with the primary jet and influences the flow field although the momentum ratio has a 100:1 order of magnitude. The results also show that the big primary jets dictate the flow field in the primary zone as well as the secondary zone. However, relatively smaller jets mainly influence the primary combustion zone because most of the jet is recirculated back to the CRZ. Also, the jet penetration is reduced with 25% and 11.5% corresponding to a 77% and 62% reduction of the jet’s area, respectively. The study indicates the presence of a critical jet diameter beyond which the dilution jets have minimum impact on the secondary region. The jet off-centering shows significant effect on the flow field though it is in the order of 0.4 mm. The fuel injection is also shown to influence the flow field as well as the primary jets angle. High fuel flow rate is shown to have very strong impact on the flow field and thus results in a strong distortion of both the primary and secondary zones. The results provide useful methods to be used in the flow field structure control. Most of the effects shown are attributed to the difference in jet opposition. Hence, the results are applicable to reacting flow.
Main Steam Piping Girth Weldment Stresses and Life Consumption Considering Malfunctioning Supports
Authors: Cohn Marvin J.
Published: September 2010

A high energy piping (HEP) program is important for the safety of plant personnel and reliability of the generating units. HEP weldment failures have resulted in serious injuries, fatalities, extensive damage of components, and significant lost generation. Since creep/fatigue is a typical failure mechanism, the probability of HEP failures increases with unit age. The main steam (MS) piping system is one of the most critical HEP systems. Weldment failures are typically due to a combination of high temperature creep and fatigue. Industry best practices include (1) the evaluation of historical operating conditions; (2) examinations of critical weldments to reveal nondestructive examination (NDE) indications, microstructural material damage, and detailed geometry data; (3) hot and cold walkdowns to document the field piping system behavior and anomalies; (4) simulation of as-found piping displacements to estimate actual stresses; (5) ranking of critical weldments; (6) recommendations for support repairs and adjustments; (7) recommendations for future examinations; and (8) remaining life estimates at critical weldments. Appropriate examinations, condition assessments, and recommendations for corrective actions are provided as a cost-effective life management process to maintain the piping system integrity. This paper provides examples demonstrating that the girth welds ranked below the top five to six welds are subject to significantly less applied stress and have substantially more creep/fatigue life than the top ranked welds. Hanger adjustments, along with selective identification, NDE, and possible repairs of top ranked welds provide substantially greater life to MS piping systems. Some fitness-for-service and risk-based programs for MS piping system girth weldments recommend a stress evaluation using typical pressure vessel or boiler tube calculations, in which the hoop stress is the principal stress. In some cases, the effective weldment stresses can be more than 50% above the hoop stress, resulting in the estimated remaining lives less than 15% of the life estimates using the hoop stress methodology. Some HEP life management programs may vaguely discuss using the principal stress based on a finite element analysis of the piping system. These principal stress values may be based on a conventional as-designed piping stress analysis. In the majority of the as-found piping stress analyses performed by the author, the maximum as-found stresses are substantially greater than the maximum conventional as-designed piping stresses. In the example case study, the maximum effective weldment stress was more than three times greater than the estimated as-designed piping stress at the same location. This paper illustrates than an as-designed piping stress analysis will typically overestimate the life of an HEP system and typically not predict the locations of maximum creep/fatigue damage.
Spatial coherence in electron-beam patterning
Authors: Perera Ginusha M. , Stein Gila E. , Liddle J. Alexander
Published: September 2010

The authors demonstrate a simple method to identify noise sources in electron-beam systems and accurately quantify the resulting errors in feature placement. Line gratings with a 46 nm average pitch were patterned with electron-beam lithography and measured with transmission x-ray diffraction (XRD) and scanning electron microscopy (SEM). All SEM micrographs were analyzed in Fourier space to facilitate comparison with the XRD data. Diffraction profiles and Fourier transforms of SEM micrographs contained numerous “satellite” peaks, meaning weak peaks adjacent to the strong primary nodes, that are characteristic of periodic extensions and compressions in the grating pitch. The wavelength and amplitude of these pitch variations were calculated with a simple scaling law by comparing the positions and intensities of satellite peaks relative to their neighboring primary nodes. This approach is remarkably easy to implement because it does not require any modeling of electron density profiles. Data were used to calculate the frequency of each noise source and the resulting variations in the grating pitch. Two persistent noise frequencies were detected in the tool studied, (62±2) Hz and (86±3) Hz, and the tool manufacturer identified likely noise sources as electromagnetic and mechanical in nature, respectively. The 60 Hz noise produced errors in a 46 nm grating pitch of 3σ=1.5 nm, where σ is the standard deviation in the grating pitch. Errors due to the 86 Hz noise ranged from 3σ=1.5 to 2.5 nm. Variations of these magnitudes can be expected to have adverse effects on coupling efficiencies, cavity quality factors, and center wavelength values in photonic devices.
New developments in the medicinal chemistry of carboranes
Authors: Satapathy Rashmirekha , Dash Barada Prasanna , Maguire John A. , Hosmane Narayan S.
Published: September 2010

The advancements in the synthetic chemistry of carboranes and metallacarboranes have given rise to diversified uses in medicinal chemistry, resulting in many new medical applications. An overview of the medicinal chemistry of carboranes is presented emphasizing the use of nanoparticles, dendrimers, porphyrins and carbohydrates as boron carriers. A review with 80 references.
Expression of octamer-4 in serous and mucinous ovarian carcinoma
Authors: Zhang Jing , Li Yan-Li , Zhou Cai-Yun , Hu Yu-Ting , Chen Huai-Zeng
Published: September 2010

Background

Octamer-4 (Oct4) is a well known regulator of self-renewal in embryonic stem cells; it has been detected in several human cancers and may play a critical role in carcinogenesis.

Aims

To assess the expression of Oct4 in epithelial ovarian tumours.

Methods

Expression of Oct4 was evaluated by immunohistochemistry in 460 cases of various epithelial ovarian lesions as well as 35 cases of normal fallopian tube epithelium. The association between Oct4 expression and various clinical pathological parameters was analysed.

Results

Oct4 expression was significantly increased from normal epithelium (both ovarian epithelium and fallopian tube epithelium) to benign and borderline cystadenoma to carcinoma in the serous lesion subgroup. Oct4 overexpression was associated with more advanced FIGO stage and higher histological grade in serous adenocarcinoma. Conversely, Oct4 expression did not differ among mucinous lesions or correlate with clinicopathological parameters in patients with mucinous adenocarcinoma.

Conclusion

Results suggest that Oct4 expression may contribute to the initiation, promotion and progression of serous ovarian carcinoma; it might be a useful biomarker for the diagnosis and outcome prediction of serous ovarian carcinoma.
Prognostic value of phosphorylated STAT3 in advanced rectal cancer: a study from 104 French patients included in the EORTC 22921 trial
Authors: Monnien Franck , Zaki Harouna , Borg Christophe , Mougin Christiane , Bosset Jean-François , Mercier Mariette , Arbez-Gindre Francine , Kantelip Bernadette
Published: September 2010

Background

Signal transducer and activator of transcription 3 (STAT3) has been implicated as an oncogene in several neoplastic diseases. However, the biological effects of STAT3 have not been extensively studied in rectal carcinogenesis.

Aims

To evaluate STAT3 activation in advanced rectal cancers and its association with clinicopathological variables and prognosis.

Methods

Nuclear immunohistochemical expression of phosphorylated STAT3 (p-STAT3) was studied in 104 advanced rectal cancers (T3–T4). All patients were participating in the EORTC 22921 trial to assess whether preoperative chemoradiotherapy followed by postoperative chemotherapy improved overall and progression-free survival.

Results

Nuclear p-STAT3 expression was detected in 37.5% of rectal cancer patients. No correlation was observed between p-STAT3 and any clinicopathological variables tested. However, patients with tumours positive for p-STAT3 had significantly improved overall survival.

Conclusion

These results highlight an unexpected role for nuclear p-STAT3 expression in advanced rectal cancers and need further investigation to clarify this finding.
Dilemmas in cytodiagnosis of subcutaneous swellings: mimics and look-alikes of cysticercosis
Authors: Rao Ram Nawal , Krishnani N , Malhotra Kiran , Suresh B , Mehrotra Ravi
Published: September 2010

Background

Fine needle aspiration (FNA) is the modality of choice in the initial characterisation of subcutaneous swellings. The site, distribution, number and clinical association of such swellings determines to a large extent the clinical diagnoses rendered in these cases.

Aims and Methods

15 unusual cases of subcutaneous cysticercosis, diagnosed by FNA, which clinically simulated diverse aetiologies, are reported.

Results

Three cases occurred in patients with known malignancies which were thought to be metastatic deposits. In another nine cases the clinical diagnoses included lymphoma, squamous cell carcinoma, neurofibroma and lipoma. Two cases strongly mimicked tubercular lymphadenitis, while one case occurred in a renal transplant recipient.

Conclusions

FNA may help diagnosis of a parasitic aetiology in cases where malignancy or tuberculosis is a clinical probability. Cysticercosis should be an integral part of the differential diagnosis of all subcutaneous swellings, regardless of the clinical setting. Helpful cytological clues are discussed.
Haemoglobin Bonn in a Chinese family as a cause of spurious hypoxaemia measured by pulse oximetry
Authors: So Chi-Chiu , Chan Amy Y , Chow Eudora Y , Lin Shek-Ying , Yip Sze-Fai , Szeto Siu-Cheung , Chan Li-Chong
Published: September 2010

Haemoglobin (Hb) Bonn is a newly described benign Hb variant that causes falsely depressed oxygen saturation as measured by pulse oximetry. It was found to be associated with mild haemolysis. Since its first report in a German family, no further cases have been documented in the literature. We report the first Chinese family with this Hb variant and confirm its unusual clinical presentation. No evidence of haemolysis was seen. The absence of consistent abnormalities in routine Hb tests such as high-performance liquid chromatography and gel electrophoresis means that spurious hypoxaemia is the only clue to its presence, and genotypic analysis is the preferred method for definitive diagnosis. Its positive identification is important for counselling and will help to avoid unnecessary investigation and treatment for this benign condition.
Alcohol and unnatural deaths in the West of Ireland: a 5-year review
Authors: Ingoldsby Helen , Callagy Grace
Published: September 2010

Aim

To investigate the prevalence of alcohol in unnatural deaths in the West of Ireland between 2003 and 2007.

Methods

The reports of 1669 postmortem examinations carried out at Galway University Hospitals were reviewed; 379 non-homicidal unnatural deaths were eligible for the study. Alcohol levels were measured in blood and/or urine in 311 cases. For each case, gender, age, cause of death and toxicology results were recorded.

Results

Alcohol was detected in 162 out of 311 cases (52%); 133 (82%) cases were men and 29 (18%) were women. Alcohol levels >150 mg/100 ml were found in 99 cases (61%), most commonly in 18–49-year-olds (n=74; 75%). Road traffic crashes (RTCs) (n=38; 23%), drownings (n=38; 23%) and hangings (n=25; 15%) were common unnatural deaths associated with alcohol. The majority of RTC deaths involved the driver (n=27; 71%). The alcohol level was higher than the legal driving limit of 80 mg/100 ml in 82% (n=22) and >150 mg/100 ml in 59% (n=16) of these. Mortality of passengers (n=6; 16%) and pedestrians (n=5; 13%) was less common.

Conclusions

Alcohol remains a major contributor to unnatural deaths in the West of Ireland, particularly with respect to mortality in young people. Young men are especially vulnerable. Deaths in RTCs and by drowning and hanging are commonly associated with alcohol. Many driver fatalities involve alcohol levels far above legal limits. Alcohol measurement in all unnatural deaths would facilitate more accurate determination of its role.
Prognostic relevance of light chain 3 (LC3A) autophagy patterns in colorectal adenocarcinomas
Authors: Giatromanolaki Alexandra , Koukourakis Michael I , Harris Adrian L , Polychronidis Alexandros , Gatter Kevin C , Sivridis Efthimios
Published: September 2010

Aims

The microtubule-associated protein 1 light chain 3 (LC3A) is an essential component of the autophagic vacuoles, forming a reliable marker of autophagic activity. In a previous study, the authors showed that LC3A immunohistochemistry renders three patterns of autophagic expression in breast carcinomas: diffuse cytoplasmic, perinuclear and ‘stone-like’ intracellular structures (SLS), each with a distinct prognostic relevance.

Methods

Tumour tissues from 155 patients with stage IIA–III colorectal adenocarcinomas, treated with surgery alone, were assessed immunohistochemically for LC3A. Median values were used as cut-off points to separate groups into low and high autophagic activity. Associations with prognosis and with lactate dehydrogenase-5 (LDH5) were sought.

Results

High SLS counts were associated with metastases and poor prognosis, while the prominence of the perinuclear pattern was linked to localised disease and good prognosis. The cytoplasmic pattern was irrelevant. Furthermore, patients with increased SLS numbers, but suppressed perinuclear expression, were associated with LDH5 overexpression and had an extremely poor prognosis (3-year survival 16.5%). The prognosis improved considerably when high SLS counts were accompanied by intense perinuclear expression (3-year survival 67%) and were optimal when SLS numbers dropped below median values, irrespective of perinuclear status (3-year survival 94–100%). Multivariate analysis showed that SLS and perinuclear patterns were independent predictors of death events.

Conclusions

Perinuclear LC3A accumulation in colorectal tumour cells is a marker of good prognosis, presumably reflecting a basal autophagic activity. An abnormal or excessive autophagic response, as indicated by increased numbers of SLS, is linked to metastasis and poor prognosis.
Constructing prognostic model incorporating the 2004 WHO/ISUP classification for patients with non-muscle-invasive urothelial tumours of the urinary bladder
Authors: Pan Chin-Chen , Chang Yen-Hwa , Chen Kuang-Kuo , Yu Hui-Jung , Sun Chih-Hao , Ho Donald M T
Published: September 2010

Aim

To construct a prognostic model for recurrence-free survival (RFS), progression-free survival (PFS) and cancer-specific survival (CSS) for patients who have undergone transurethral resection of non-muscle-invasive (pTa/pT1) urinary bladder urothelial tumours.

Methods

1366 patients who had undergone transurethral resection of primary non-muscle-invasive urothelial tumours (pTa, 891 patients; pT1, 475 patients) confined to the bladder were retrospectively studied. Tumours were classified according to the 2004 WHO/International Society of Urologic Pathology grading system. Kaplan–Meier and stepwise Cox regression models were applied, and 200 bootstrap resamples were used to generate survival estimates and 95% CIs. A nomogram was developed that incorporated significant variables predicting survival.

Results

RFS, PFS and CSS probabilities for non-muscle-invasive bladder urothelial tumours were calculated. Incorporating salient prognostic factors (tumour grade, pT stage, patient age, status of intravesical instillation), the model satisfactorily predicted PFS (concordance index=0.79) and CSS (concordance index=0.87).

Conclusions

Robust nomograms were created to predict PFS and CSS. These data provide an overall perspective of disease outcomes which may aid in developing individualised follow-up programmes.
Composite cervical adenocarcinoma composed of adenoma malignum and gastric type adenocarcinoma (dedifferentiated adenoma malignum) in a patient with Peutz Jeghers syndrome
Authors: McCluggage W Glenn , Harley Ian , Houghton Joseph P , Geyer Felipe C , MacKay Alan , Reis-Filho Jorge S
Published: September 2010

An unusual cervical adenocarcinoma is reported in a 50-year-old woman with a history of Peutz Jeghers syndrome. The carcinoma contained two morphologically distinct and spatially separate components, one comprising typical well differentiated adenoma malignum and the other a moderately differentiated neoplasm, in keeping with gastric type adenocarcinoma. Both components were positive for HIK1083 and MUC6 and negative for p16, and did not contain human papillomavirus. It is believed that such a composite tumour has not been described in the literature. It is believed that the component of gastric type adenocarcinoma arose through a process of dedifferentiation within adenoma malignum and we provide circumstantial molecular evidence in support of the interpretation that both components may be clonally related in that they displayed an extra copy of chromosome 7. This raises the possibility of a relationship between these two uncommon types of cervical adenocarcinoma, both of which are thought to exhibit gastric differentiation.
Endoscopic biopsies of duodenal polyp/mass lesions: a surgical pathology review
Authors: Kanthan Rani , Gomez Daniel , Senger Jenna-Lynn , Kanthan Selliah Chandra
Published: September 2010

Background and Aims

Endoscopic biopsies of duodenal polyp/mass lesions are uncommon surgical pathology specimens. A surgical review with a report on three unusual duodenal polyp/mass lesions is presented.

Methods

A computer-based data search of duodenal polyp/mass lesions was conducted at the Saskatoon Health Region using the Lab Information System from 1996 to 2009. The source codes used included DUOBX and DUO. Surgical material on the retrieved cases was reviewed.

Results

The three index cases included duodenal polyp/mass lesions, which on primary analysis were diagnosed as ‘poorly differentiated’ carcinomas with some unusual features. The accurate diagnoses of metastatic renal cell carcinoma, metastatic phaeochromocytoma and metastatic malignant melanoma, respectively, were confirmed with retrospective analysis of previous clinical and pathological records. 130 duodenal polyp/mass related lesions were identified. 33% of these lesions were malignant and 67% were benign/normal. The majority of these biopsies originated in patients aged 60–79 years. Malignant lesions were more common in men (61%) than women (39%). 88% of the malignant cases were of carcinomatous origin. 16.3% of the carcinomas were reclassified as metastatic lesions arising from lung, breast, colon and pancreas. 41% of the benign cases had no significant pathological abnormalities. The remainder were predominantly adenomatous (14.9%) and inflammatory (13.8%) in origin.

Conclusions

Endoscopic biopsies of duodenal polyp/mass lesions remain an uncommon specimen (0.01% in the authors' surgical pathology practice). Nevertheless, accurate identification of the exact pathology, even in ‘poorly differentiated’ high-grade carcinomas is advocated, as metastatic lesions will require specific treatment plans in conjunction with treatment of their primary tumour.
Upper aerodigestive tract lymphoma in Taiwan
Authors: Chen Shang-Wen , Chang Sheng-Tsung , Lu Chin-Li , Hwang Wei-Shou , Tsao Chao-Jung , Huang Wen-Tsung , Chang Kwang-Yu , Chuang Shih-Sung
Published: September 2010

Aim

To better understand the spectrum of primary lymphomas in the upper aerodigestive tract, a common site of extranodal lymphoma.

Materials and methods

Lymphoma cases diagnosed at an institution in southern Taiwan from 1992 to 2007 were retrospectively studied with pathology and history review, immunohistochemistry, in situ hybridisation for Epstein–Barr virus (EBER-ISH), and statistical analysis.

Results

70 patients were identified. The male to female ratio was 2:1, and the median age was 61.5 years (range 8–87); 73% of cases occurred in Waldeyer's ring or the oral cavity. Phenotypically, there were 45 (64%) B cell and 25 (36%) T cell or extranodal natural killer (NK)/T cell lymphoma (ENKL) including 42 (60%) diffuse large B cell lymphomas (DLBCLs), 22 (31%) ENKLs, three unspecified peripheral T cell lymphomas, two follicular lymphomas and one Burkitt lymphoma. EBER-ISH was positive in three (7%) of 42 DLBCLs and all 22 ENKLs. Most patients received chemotherapy with or without radiotherapy. The 5-year overall survival for all patients was 56.3% with B and T or NK/T cell lymphomas at 66.0% and 40.6%, respectively. Univariate analysis revealed that sinonasal presentation, T or NK/T cell phenotype, raised lactate dehydrogenase (LDH) activity, and Ann Arbor stage III/IV diseases were associated with prognostically significant higher hazard ratio (HR) of lymphoma-related death. However, only raised LDH remained significant on multivariate analysis. For DLBCLs, only raised LDH was prognostically significant on either univariate or multivariate analysis.

Conclusions

Only a limited number of lymphoma entities occurred primarily in this anatomical region. The 5-year overall survival rate was comparable to other reports, and raised LDH at diagnosis was the only significant prognostic factor identified. A relatively high incidence of EBV positivity was identified in DLBCLs in this anatomical region, and further studies are warranted to elucidate the clinicopathological significance of these tumours.
Phasing-out tobacco: proposal to deny access to tobacco for those born from 2000
Authors: Khoo Deborah , Chiam Yvonne , Ng Priscilla , Berrick A J , Koong H N
Published: September 2010

As a contribution to worldwide efforts towards a tobacco-free society, this paper considers the possibility of a long-term phasing-in of a total ban, by proposing that individuals born in or after the year 2000 have their supply of tobacco restricted. In conjunction, a survey that we have conducted in Singapore indicates strong public support (even among current smokers) for the proposal.
Nicotine reduction revisited: science and future directions
Authors: Hatsukami Dorothy K , Perkins Kenneth A , LeSage Mark G , Ashley David L , Henningfield Jack E , Benowitz Neal L , Backinger Cathy L , Zeller Mitch
Published: September 2010

Regulation of nicotine levels in cigarettes and other tobacco products is now possible with the passage of the Family Smoking Prevention and Tobacco Control Act (FSPTCA) in 2009, giving the US Food and Drug Administration (FDA) authority to regulate tobacco products, and with Articles 9-11 of the WHO Framework Convention on Tobacco Control. Both regulatory approaches allow establishing product standards for tobacco constituents, including nicotine. The FSPTCA does not allow nicotine levels to be decreased to zero, although the FDA has the authority to reduce nicotine yields to very low, presumably non-addicting levels. The proposal to reduce levels of nicotine to a level that is non-addicting was originally suggested in 1994. Reduction of nicotine in tobacco products could potentially have a profound impact on reducing tobacco-related morbidity and mortality. To examine this issue, two meetings were convened in the US with non-tobacco-industry scientists of varied disciplines, tobacco control policymakers and representatives of government agencies. This article provides an overview of the current science in the area of reduced nicotine content cigarettes and key conclusions and recommendations for research and policy that emerged from the deliberations of the meeting members.
Rock squeeze at Thorold Tunnel
Authors: Bowen C. F. P. , Hewson F. I. , MacDonald D H , Tanner R. G.
Published: September 2010

The Thorold Tunnel, constructed between 1965 and 1968, provides a four-lane highway crossing under the Welland Canal at Thorold, Ontario. Horizontal cracking, initially observed in late 1967, has since become more evident in the outer walls of the tunnel at the east and west service buildings. This paper describes the instrumentation installed, and the investigations into the cause of cracking carried out between 1971 and 1974. These investigations have led to the conclusion that the cause of the cracking is an imposed deformation resulting from a time-dependent, non-elastic displacement of the adjacent rock mass, known as rock squeeze. The effect of a slot cut in the rock in 1974 to relieve the west service building from the deformations imposed by the rock squeeze is also reviewed.
Frost heave and heaving pressure measurements in colliery shales
Authors: Kettle R. J. , Williams R. I. T.
Published: September 2010

The paper describes a technique for measuring the pressure generated when heaving is restrained in a frozen soil, freezing being achieved by thermoelectric cooling. Although steps were taken to minimize side wall resistance between the specimen and the test mould significant under-estimation of the pressure was unavoidable and further work is necessary to accurately quantify the resistance.The tests were performed on specimens of unbound and cement stabilized colliery shale, both unburnt and burnt shales being studied. For the unbound shales, the largest heaving pressures were developed by the finer grained shales, and this supports the theoretical studies that have shown heaving pressure to be inversely proportional to pore size. Cement stabilization did not significantly affect the heaving pressure developed by the coarser grained shales but, with the finer grained shales, it reduced the pressure developed.Heave and heaving pressure are not uniquely related and, although relationships have been established between these parameters separately for burnt and for unburnt shale, the technique does not at present constitute an alternative to the frost heave test.The testing programme has shown, however, that thermoelectric devices provide a reliable and efficient means for freezing specimens and an experimental rig is suggested for using them in frost heave testing.
Testing of drivability of concrete piles and disturbance to sensitive clay
Authors: Fellenius Bengt H. , Samson Laval
Published: September 2010

The results reported are of an investigation of a group of thirteen 12 in. (30 cm) diameter precast concrete piles driven through 60 ft (18 m) of sensitive marine clay followed by 10 ft (3 m) of silt and sand and 13 ft (4 m) of very dense silt to end bearing in glacial till. The purpose of the test is to study the drivability of the piles through very dense soil and to measure the disturbance caused to the sensitive clay by the driving of displacement piles. Following a literature review, the paper presents the soil conditions at the site and the testing program. The test results are discussed and experience gained from the follow-up of the driving of 520 piles at the site is presented.Visual observations during pile driving, and analysis of driving records, show that a high pile quality is necessary at the site. The large driving resistance encountered in the very dense silt (150 to 300 blows/ft) would prevent low quality piles from reaching the competent glacial till and developing the needed bearing capacity.Pile loading tests showed the piles to have an ultimate bearing capacity exceeding 450 tons (4.0 MN). It was established that the shaft resistance in the clay during test loading was between 100 and 125% of the undrained shear strength of the clay as measured by field vane testing. In comparison, an uplift test to failure showed that the uplift shaft resistance along the pile in the clay was only 60% of the undrained shear strength of the clay.The pile driving developed large pore pressures in the clay which exceeded the effective overburden stresses. The excess pore pressures dissipated over a period of slightly more than 3 months. Vane testing within the pile group immediately after driving showed that a shear strength reduction of about 15% was caused by the piles. At a distance of 2 ft (0.6 m) outside the pile group, no strength reduction was found. The reduction within the group was gradually regained during the dissipation of the induced pore pressures. Laboratory testing on clay samples obtained within the pile group 75 days after pile driving showed a smaller value of the preconsolidation pressure of the clay, but no change in the compression indices.
Steady-state and quasi-static thermal results for bare and insulated pipes in permafrost
Authors: Thornton D. E.
Published: September 2010

Analytical and semi-analytical results relating to the transient and steady-state thermal regime around uninsulated and insulated pipelines buried in permafrost are presented.A comparison of the results with some published numerical work is included.
A versatile hollow cylinder triaxial device
Authors: Dusseault Maurice B.
Published: September 2010

A high-pressure, thick-walled hollow cylinder test device has been perfected to explore the consequences of stress paths which are typical of pressuremeter configurations, tunnelling, or shafting in soil materials. Several features have been incorporated to facilitate data gathering, and the device is readily adaptable to K0 or standard compression and extension triaxial tests. It has been used on tests in artificially prepared dense sand specimens constructed by a freezing technique, and will be used in an extensive study of the behavior of oil sands. Typical results of tests on dense Ottawa sand (C-109) are presented.
Growth of first-year sea ice, Eclipse Sound, Baffin Island, Canada
Authors: Sinha N. K. , Nakawo M.
Published: September 2010

A simple numerical integration method has been developed for predicting growth of ice under snow cover where solar radiation does not play a dominant role. The method is capable of incorporating variations in snow conditions and physical properties of ice and snow during the growth period. Theoretical predictions compare favourably with field observations in Eclipse Sound, Baffin Island, for the winter seasons of 1977–78 and 1978–79.
Design of tunnel lining in rock for long term time effects
Authors: Lo K. Y. , Yuen Clement M. K.
Published: September 2010

Excavation of underground openings in rock relieves the in situ state of stresses, providing an initiating mechanism for time-dependent deformation in shaly rocks to occur. The construction of a permanent lining restrains the rock movement, resulting in an increase with time of pressure acting on the lining.Closed form solutions for this problem of rock structure – time interaction of circular tunnels have been developed, taking into account (a) the state of initial stresses, (b) the time-dependent properties of the lining as well as the rock, and (c) the time lapsed between excavation and lining. Expressions for lining pressures, stresses, thrusts, and moments are given for both "no slip" and "full slip" interface conditions.The effects of material parameters, lining flexibilities, and time lapse on quantities of engineering interest are studied and their implications on design illustrated.The results of analysis are compared with the field observations made in three tunnels. It is shown that the theoretical results are consistent with the observed extent and location of cracking in these tunnels.It is suggested that the methods proposed may be used for design considerations of permanent linings of tunnels in rock exhibiting significant time-dependent deformation.
Dynamic soil–structure interaction modelled experimentally on a geotechnical centrifuge
Authors: Morris Derek V.
Published: September 2010

Certain simple problems in dynamic soil–structure interaction were investigated experimentally—in particular the rocking behaviour of rigid foundations on cohesionless soil. This was done using model tests in a geotechnical centrifuge, in order to preserve the correct level of stress in the soil.These tests observed the behaviour of model towers with rigid foundations of varying sizes and geometries. Perturbation of a tower allowed the dynamic properties to be measured and the stiffness of the foundation to be evaluated. Simple elastic theory satisfactorily predicted the observed behaviour, provided that appropriate assumptions were made about the soil stress under the foundation, and an empirical rule is suggested. The limitations of a more elaborate analysis are demonstrated. It was also possible to observe that the foundation stiffness for embedded foundations appeared to be overestimated theoretically and that the effect of dynamic interaction between adjacent towers appeared to be small.
Causes of sampling disturbance and design of a new sampler for sensitive soils
Authors: Rochelle P. La , Sarrailh J. , Tavenas F. , Roy M. , Leroueil S.
Published: September 2010

The behaviour of a clay element during the sampling operation is first analysed in the light of the limit state theory. The stress variation and the resulting distortion of the clay element during sampling is equivalent to a destructuration of the clay, and its mechanical properties are greatly affected. The causes of sampling disturbance are analysed and the principles which should govern the design of a good quality sampler are reviewed in the light of previous studies. It is shown how the reshaping of the sampling tubes can improve the sample quality. The new 200 mm sampler designed at Université Laval uses the overcoring technique to eliminate suction and to insure the recovery of large samples without a piston. The quality of these large samples has been proven to be equivalent to block samples. The advantages and limitations of the Laval sampler are discussed.