bluuebunny/crossref_metadata_2025_split huggingface dataset:
FNA of misclassified primary malignant neoplasms of the thyroid: Impact on clinical management
Authors: Faquin William C. , Izquierdo Roberto , Khurana Kamal K. 
Published: March 2009

Background:Fine needle aspiration (FNA) cytology is a popular, reliable and cost effective technique for the diagnosis of thyroid lesions. The aim of our study was to review cases of misclassified primary malignant neoplasms of the thyroid by FNA, and assess the causes of cytologic misdiagnosis and their impact on clinical management.Methods:Clinical data, FNA smears and follow-up surgical specimens of cases diagnosed with primary thyroid carcinoma were reviewed.Results:Of the 365 cases with a malignant diagnosis by FNA over a period of 11 years, nine (2.4 %) were identified with discrepant histologic diagnosis with regard to the type of primary thyroid malignancy. In addition, four cases were added from the consultation files of the Massachusetts General Hospital. Areas of difficulty contributing to misclassification included overlapping cytologic features (n = 6), rarity of tumors (n = 3), and sampling limitations (n = 4). Of the 13 cases, 12 underwent total or near total thyroidectomy and one patient had concurrent surgical biopsy. Measurement of serum calcitonin levels in one case, with an initial cytologic diagnosis of medullary carcinoma, prevented unnecessary lymph node dissection. Misclassification of medullary carcinoma as papillary carcinoma precluded lymph node dissection in one case. Further management decisions were based on the final histologic diagnosis and did not require additional surgery. Two cases of undifferentiated (anaplastic) thyroid carcinoma were misdiagnosed as papillary thyroid carcinoma. Both patients received total thyroidectomies, which may not otherwise have been performed.Conclusions:A small subset of primary malignant neoplasms of the thyroid may be misclassified with regard to the type of malignancy on FNA. The majority of primary malignant neoplasms diagnosed on FNA require thyroidectomy. However, initial cytologic misclassification of medullary carcinoma or undifferentiated carcinoma as other malignant neoplasms or vice versa may have an impact on clinical management.
Pleomorphic adenoma with squamous and appendageal metaplasia mimicking mucoepidermoid carcinoma on cytology
Authors: Batrani Meenakshi , Kaushal Manju , Sen A. K. , Yadav Rajbala , Chaturvedi N. K. 
Published: March 2009

Background:
Histological diversity is the hallmark of pleomorphic adenoma, the most common salivary gland tumor. It may cause difficulty in cytological interpretation, due to limited and selective sampling.

Case presentation:
A 16-year-old female patient presented with right cheek swelling. Fine needle aspiration cytology showed squamous cells, basaloid cells, and foamy cells, along with extracellular keratin and foreign body giant cells. Characteristic metachromatic fibrillary chondromyxoid stroma, which is usually seen in pleomorphic adenoma, was not seen in the aspirate. A diagnosis of mucoepidermoid carcinoma was given on cytology. Subsequent resection revealed an encapsulated pleomorphic adenoma, with extensive squamous metaplasia and appendageal differentiation on histology.

Conclusion:
This case illustrates that pleomorphic adenoma with squamous metaplasia presents a potential for misinterpretation as mucoepidermoid carcinoma on cytology. We discuss the various pitfalls and the features that are helpful in distinguishing these two lesions.
Simulation of temperature peak attenuation by catalyst dilution in a tubular packed‐bed reactor
Authors: Danziger D. , Popović D. , Schulz‐Ekloff G. 
Published: March 2009

AbstractTemperature peak attenuation is an important problem for safe process control. Simulations of the axial temperature and product progression in stationary ammonia synthesis with different axial catalyst dilutions have been carried out. It is demonstrated that the requirement of temperature peak attenuation together with a maximum product yield can be met by an optimal catalyst dilution profile at the entrance of the bed.
Dispersed phase holdup and drop size distributions in reciprocating plate columns
Authors: Rao N. V. Rama , Srinivas N. S. , Varma Y. B. G. 
Published: March 2009

AbstractThe paper covers an experimental and theoretical investigation of the dispersed phase holdup and drop size distribution for gas‐liquid and liquid‐liquid counter‐current flow in reciprocating plate columns provided with plates having small hole size and free area. The response of the reciprocating plate column is similar to that of liquid‐pulsed columns exhibiting mixer‐settler and emulsion regions. The dispersed phase holdup depends on the dispersed phase flow rate, the vibrating speed of the plate stack, the plate geometry and the number of plates: it was found to be minimum at the transition between the mixer‐settler and emulsion regions.The dispersed phase holdup is modeled incorporating apparent interstitial liquid velocity and the slip velocity to account for the non‐descriptive flow pattern between the phases.The drop size distribution is satisfactorily represented on a Rosin–Rammler Chart. Sauter mean diameter, calculated from the distributions, indicated an advantage in the drop size‐power consumption relation when plates having small hole size and free area are used.Equipment used for fluid‐fluid contacting is often broadly classified as either stagewise or differential contactors. The classification is further sub‐divided as gravity, mechanically‐agitated and pulse‐agitated, depending on the method adopted for interdispersing the phases. Pulse‐agitation involves the use of either reciprocating perforated plates moving vertically up and down the column, or pulsing a phase hydraulically keeping the internal structure of the column stationary.The literature on reciprocating plate columns (RPC) primarily is concerned with the study of liquid‐liquid systems using perforated plates having large hole size and free area. This paper presents the dispersed phase holdup and drop size distributions for gas‐liquid and liquid‐liquid systems in reciprocating plate columns with small perforation diameter and free area for the plate.
Modelling of resonant behavior during forced cycling of catalytic reactors
Authors: Lynch David T. 
Published: March 2009

AbstractA model, based on a Langmuir‐Hinshelwood type mechanism, for the oxidation of carbon monoxide on a platinum catalyst is presented. This model is used to explain resonant behavior which has been observed during forced feed composition cycling of catalytic reactors. This model further predicts that catalytic reactions can display pathological behavior under certain conditions of feed cycling in agreement with experimental observations.
Physical effects on Fischer–tropsch synthesis over composite Ru catalysts
Authors: Yang C.‐H. , Goodwin J. G. 
Published: March 2009

AbstractFischer–Tropsch synthesis was studied over composite catalysts formed by adding SiO2 to Ru/Al2O3 and to Ru/TiO2. The two Ru primary catalysts alone had reasonably similar catalytic properties for this synthesis. It was found that the presence of excess amounts of SiO2 with the primary Ru catalysts can produce significant changes in conversion and product selectivity, depending upon the support used. It is suggested that the effects produced by the physical presence of this inert material are due to a combination of primary catalyst activity, product selectivities, possible secondary reactions, heat and mass transfer effects, and reaction conditions. These results emphasize the importance of considering both physical and chemical effects when developing any composite catalyst mechanism.
An experimental laboratory fixed bed study on the atmospheric pressure gasification of poplar bark with steam
Authors: Kumar Ashwani , Mann R. S. 
Published: March 2009

AbstractAn experimental study has been made of the gasification of poplar bark particles exposed to a helium/water vapor atmosphere in a fixed‐bed reactor at 873–973 K. with and without silica catalyst. The effect of temperature on gas yields, calorific value and carbon conversion was evaluated for the pyrolytic conversion and steam‐char gasification stages. The kinetics of the production of various gases in catalytic steam‐char reaction has been studied.
Solubilities of gaseous butadiene and butene‐2 in possible extractive distillation solvents
Authors: Asatani Haruki , Hayduk Walter 
Published: March 2009

AbstractSolubilities of 1,3‐butadiene and trans‐2‐butene are reported for a pressure of 101.325 kPa and temperatures ranging from 278 to 323 K in the solvents carbon disulfide, acetic acid, acetone, dimethyl formamide, dimethyl acetamide, and ethyl acetate. The solvents were chosen to attempt to elucidate the complex molecular interactions that occur with certain reactive gases and some commercial extractive distillation, as well as other solvents.
Interfacial tension behavior of athabasca bitumen/aqueous surfactant systems
Authors: Isaacs E. E. , Smolek K. F. 
Published: March 2009

AbstractThe spinning drop method was used to measure the interfacial tension of Athabasca bitumen in contact with an aqueous phase (D2O); variables included temperature, salinity, alkalinity, surfactant type (TRS 10–80, Suntech 5, sodium dodecyl sulfate), surfactant concentration, isopropyl alcohol concentration, bitumen drop size and age of interface. In the absence of surfactant, the bitumen/aqueous interfacial tension decreased with increasing temperature and salinity. Bitumen drops contacting alkaline medium exhibited interfacial tension minima below a pOH of three. In the presence of surfactant, the interfacial tension behavior was often complex. The interfacial tension‐concentration plot for Suntech 5 surfactant exhibited two CMC type discontinuities. Low interfacial tension (<0.01 mN m−1) was observed only in the presence of added electrolyte. Interfacial tension values were sensitive to the age of surfactant preparation and volume ratio of the oleic‐to‐aqueous phases. The interfacial tension of the bitumen/brine‐TRS 10–80 system increased upon addition of isopropyl alcohol. An increase in temperature required an increase in salinity to maintain a constant low interfacial tension. The experimental results are discussed in terms of changes in the structure of the amphiphile at the bitumen/aqueous interface.
Measurement of enthalpies of mixing in gaseous phase for the binary system carbon dioxide – hydrogen sulphide by an isothermal flow calorimeter
Authors: Barry Alpha O. , Kaliaguine Serge C. , Ramalho Rubens S. 
Published: March 2009

AbstractEnthalpies of mixing for the binary system carbon dioxide – hydrogen sulphide were measured by means of an isothermal flow calorimeter at temperatures of 293.15. 305.15 and 313.15 K. For the first isotherm, excess enthalpy measurements were made at pressures of 0.507, 1.013 and 1.419 MPa. For the last two isotherms, these measurements were performed at pressures of 0.507, 1.013 and 1.520 MPa. The experimental data were treated by the same techniques described for the systems previously studied (Barry et al., 1982a, 1982b, 1982c).Two types of binary interaction coefficients kij have been utilized for the prediction of experimental data from equations of state: coefficients kij independent of temperature and pressure, and kij's adjusted as function of temperature and pressure. A better prediction of the excess enthalpy experimental data was obtained from the latter series of binary interaction coefficients.
Estimation of the liquid‐phase enthalpy of mixing for the binary mixture 1,3 dioxolane‐water
Authors: Castellari Carlo , Francesconi Romolo , Bubani Bianca , Comelli Fabio 
Published: March 2009

AbstractThe liquid‐phase enthalpy of mixing δHm of the binary system 1,3 dioxolane‐water was calculated from existing isobaric liquid‐vapor equilibrium data.The liquid‐vapor data were correlated by the equations of Margules (with three parameters), Redlich‐Kister (with four and five parameters), Wilson, NRTL and LEMF in order to obtain the unknown parameters. From the corresponding analytical expressions for GE the values of δHm were calculated and compared with reported experimental values. Only the Redlich‐Kister expressions provided calculated δHm curves showing the inversion of sign typical of the experimental curves, whereas the Wilson expression gave the best agreement between the calculated and the experimental values of the heat of mixing.On a calculé l'enthalpie de mélange en phase liquide δHm du système binaire, 1,3 dioxolane‐eau, à partir des données isobares d'équilibre liquide‐vapeur.
Isobutane production with a catalytic reformer pretreater
Authors: Yan T. Y. 
Published: March 2009

AbstractFor some refineries, production of isobutane is economically viable; for others, isobutane self‐sufficiency is strategically important. However, a process unit specifically for isobutane production often is not justified.A process has been developed to use an existing unit to produce isobutane on demand. In this process, the reformer pretreater is filled with a special catalyst with a high selectivity for desulfurization over hydrocracking. It can pretreat the reformer feed to low sulfur levels at low temperatures without significant hydrocracking; this selectivity can be further enhanced by temporary poisoning with nitrogen compounds.The catalyst is also active for hydrocracking so that, when isobutane is in demand, a moderate increase in reactor temperature allows the production of butanes at a high iso‐to‐normal ratio while maintaining desulfurization. Preliminary tests indicate that catalyst stability appears excellent.
The minimum spouting velocity in conical beds
Authors: Kmieć Andrzej 
Published: March 2009

AbstractA theoretical model, describing the equilibrium of forces resulting from gas flow resistance, bed weight and internal solid friction at the point of the minimum spouting velocity, is proposed.An equation for predicting the minium spouting flow rate has been developed and verified by the experimental data obtained in 8 columns with diameters varying from 0.09 m to 0.9 m.
Studies on the solid circulation rate and gas bypassing in spouted fluid‐bed with a draft tube
Authors: Yang Wen‐Ching , Keairns Dale L. 
Published: March 2009

AbstractExperiments were performed in a 28.6 cm diameter transparent semicircular vessel with a 9.6 cm diameter draft tube using polyethylene beads (ρs = 0.91 g/cm3) and hollow epoxy spheres (ρs = 0.21 g/cm3) as the bed material to study the effect of operating conditions, the distributor plate design, and the draft tube inlet configurations on the solid circulation rate and the gas distribution between the downcomer and the draft tube. Solid circulation rate was found to be strongly affected by the design configuration at the bottom of the draft tube and the downcomer, which provided different gas bypassing characteristics and resulted in different amount of aeration in the downcomer region.
Studies of spouted beds with small outlet‐inlet cross‐section ratios
Authors: Dolidovich A. F. , Efremtsev V. S. 
Published: March 2009

AbstractAn experimental study of the hydrodynamics, structure, mixing and interphase heat transfer of spouted beds of fine dispersed materials in conic‐cylindrical columns with the small outlet‐to‐inlet cross‐section ratio D/D0 ≤ 3 has been made by different methods. The effect of design and operation parameters on the shape, sizes and stability of a central core, the solid phase concentration variation in the core and annulus, the circulation rate, entrainment and heat transfer in the columns with D = 100 mm have been explored. Empirical correlations have been suggested for calculating pressure drops across such beds under the developed spouting conditions and for effective gas‐to‐solid phase heat transfer coefficients.
Thick coatings by thermo‐chemical deposition in spouted beds
Authors: Piccinini Norberto , Rovero Giorgio 
Published: March 2009

AbstractSpouted beds are an established way of coating nuclear fuel microspheres with pyrolytic carbon or silicon carbide by high‐temperature thermochemical reactions. In recent years, similar coatings have aroused particular interest as bio‐compatible materials. This paper describes the differences between these two applications, and the changes that must be made to the coating process and furnace to control both the overall surface of the bed material and its increase in volume. It is shown that a satisfactory control can be achieved by continuous feeding of small particles, followed by the continuous withdrawal of variously coated particles. Experiments on two columns with internal diameter of 0.08 and 0.14 m, respectively, showed that segregation phenomena may occur, depending on the flow dynamics, and that the way in which a steady state is brought about will depend on the position of the discharge pipe in the bed.Les lits “spoutés” constituent un moyen courant pour recouvrir des microsphères de combustible nucléaire de carbone pyrolytique ou de carbure de silicum, en employant des réactions thermochimiques à température élevée. Durant les dernières années, les recouvrements du type précité ont suscité un intérět particulier en raison de leur biocompatibilité.
Comparison of coal gasification in fluidized and spouted beds
Authors: Watkinson A. P. , Cheng G. , Prakash C. B. 
Published: March 2009

AbstractTwo sub‐bituminous coals, a bituminous coal and a reject coal of 55% ash were gasified with steam and air in a 0.31‐m dia. reactor operated in the fluidized and spouted bed modes. Inert beds of 1.1 mm dia. Ottawa sand and 2.1 mm dia. gravel provided stable fluidization and spouting respectively, at superficial velocities in the range 1.3–1.6 m/s. Coals of 1.19–3.36 mm diameter were fed to the gasifier at rates up to 45 kg/h and a range of air/coal ratios. For a given coal, results in the two systems were basically similar, although differences in gas heating value, gas yield and thermal efficiency were noted for some coals.
Estimation of liquid film mass transfer coefficients for randomly packed absorption columns
Authors: Au‐Yeung Patrick H. , Ponter Anthony B. 
Published: March 2009

AbstractEmpirical and theoretical correlations, published since 1940 are reported which predict liquid film mass transfer coefficients in packed columns. Brief comments on the usefulness of the equations are given together with the range of operating variables, where available. Dimensional constants in the empirical correlations have been recalculated for the cases where the original values were not in SI units.
Anodic oxidation of phenolics found in coal conversion effluents
Authors: Chettiar M. , Watkinson A. P. 
Published: March 2009

AbstractSolutions of phenol, o‐cresol, p‐cresol, 2,3‐xylcnol, 3,4‐xylenol, resorcinol, and catechol at concentrations below I g/L were oxidized at constant current on a packed bed lead dioxide electrode with electrolyte recirculation. The effects of applied current and initial concentration on the extent of oxidation with time were explored. The observed ranking in ease of oxidation was phenol > 2,3‐xylenol > resorcinol > p‐cresol > 3,4‐xylenol > o‐cresol. Although the phenolics were largely destroyed, organic degradation products of the quinone and hydroquinone type remained in solution. A mixture of five monohydric phenols showed 96% destruction of phenolics, a 50% reduction in B.O.D. but a reduction in total organic carbon of only 22%.
Particle agglomeration and capture as a result of synergism between inertial impaction and eddy diffusion
Authors: Douglas P. L. , Dullien F. A. L. , Spink D. R. 
Published: March 2009

AbstractParticle capture experiments conducted in turbulent cross flow with various aerosols involving liquid and/or solid particulates have resulted in collection efficiencies which are in excess of the values predicted by the various known models of particle capture, i.e., inertial impaction, interception and Brownian diffusion.In one type of experiment the turbulent air stream, carrying submicron dust particles, is flowing past a cylindrical collector (such as a piece of wire) with its axis orientated perpendicular to the direction of flow. Collecting efficiencies ranging up to about 20% have been found under conditions where the conventional models of particle capture predict practically zero collection efficiencies.In another type of experiment involving injecting a fog (2–80 μm diameter water droplets) into the dusty gas stream carrying submicron size dust particles which subsequently enters a slow turning fan. While passing through the fan, the fog agglomerates into raindrops while scavenging most of the dust particles. For example, a 0.8 μm median particle size aluminum silicate pigment was collected with 97–99.5% efficiency, the exact value depending on the operating conditions.Theoretical analysis of these phenomena may be based on the idea of synergism involving inertial impaction and eddy diffusion: the smaller dust particles/drops are captured by the larger drops in the fan and the dust particles are captured by the wires because (a) there is a significant relative velocity between them and (b) because the particles undergo eddy diffusion.
Natural convection mass transfer to nonspherical objects at high rayleigh number
Authors: Weber M. E. , Astrauskas P. , Petsalis S. 
Published: March 2009

AbstractNatural convection mass transfer measurements were made by the electrochemical method for spheres and eight nonspherical shapes in several orientations. Using a characteristic length which is sensitive to orientation, a natural convection correlation is proposed for objects of any shape having sphericities larger than 0.6.
Measurement of large gasndashliquid interfacial areas
Authors: Al Taweel A. M. , Divakarla R. , Gomaa H. G. 
Published: March 2009

AbstractThe light attenuation technique has been modified to expand the range of its applicability up to AL values of 460. This has been accomplished through the use of a laser as the source of monochromatic collimated light, and a very sensitive low‐bias picoammeter.The data obtained using the photographic technique were found to agree reasonably well with those from light attenuation.
Bubble measurement in three‐phase fluidized beds using a u‐shaped optical fiber
Authors: De Lasa H. , Lee S. L. P. , Bergougnou M. A. 
Published: March 2009

AbstractA photometric technique is being developed to study bubble behaviour in three‐phase fluidized beds constituted by fine particles. A custom made U‐shaped single core silica fiber (400 μm diameter) is used as the bubble sensor. A helium‐neon laser beam is introduced at one end of the U probe and the variation of the light intensity, occurring when a gas bubble contacts the sensor, is detected at the other end of the fiber. The velocity and axial length (cord) of the bubbles were measured by four such probes in a two dimensional bed. This technique could be applied to study the bubble behaviour and to provide experimental data for estimating the performance of reactors with severe operating conditions of high temperature and pressure.
Isokinetic probe sampling from slurry pipelines
Authors: Nasr‐El‐Din H. , Shook C. A. , Esmail M. N. 
Published: March 2009

AbstractA theoretical and experimental study of the errors arising in sampling through probes projecting into the flow has been conducted. Water–sand slurries with particles of surface‐mean diameter between 0.165 and 0.72 mm were considered. Theoretical predictions were performed assuming the mixture could be described by the axisymmetric potential flow relationship. Satisfactory agreement in the important intermediate K value region was achieved for tapered or thin‐walled probes. However, significant errors arise when thick‐walled blunt probes are used.