bluuebunny/crossref_metadata_2025 huggingface dataset:
The SNARE protein family of Leishmania major
Authors: Besteiro Sébastien , Coombs Graham H , Mottram Jeremy C
Published: October 2006

Background

Leishmania major is a protozoan parasite with a highly polarised cell shape that depends upon endocytosis and exocytosis from a single area of the plasma membrane, the flagellar pocket. SNAREs (soluble N-ethylmaleimide-sensitive factor adaptor proteins receptors) are key components of the intracellular vesicle-mediated transports that take place in all eukaryotic cells. They are membrane-bound proteins that facilitate the docking and fusion of vesicles with organelles. The recent availability of the genome sequence of L. major has allowed us to assess the complement of SNAREs in the parasite and to investigate their location in comparison with metazoans.

Results

Bioinformatic searches of the L. major genome revealed a total of 27 SNARE domain-containing proteins that could be classified in structural groups by phylogenetic analysis. 25 of these possessed the expected features of functional SNAREs, whereas the other two could represent kinetoplastid-specific proteins that might act as regulators of the SNARE complexes. Other differences of Leishmania SNAREs were the absence of double SNARE domain-containing and of the brevin classes of these proteins. Members of the Qa group of Leishmania SNAREs showed differential expressions profiles in the two main parasite forms whereas their GFP-tagging and in vivo expression revealed localisations in the Golgi, late endosome/lysosome and near the flagellar pocket.

Conclusion

The early-branching eukaryote L. major apparently possess a SNARE repertoire that equals in number the one of metazoans such as Drosophila, showing that the machinery for vesicle fusion is well conserved throughout the eukaryotes. However, the analysis revealed the absence of certain types of SNAREs found in metazoans and yeast, while suggesting the presence of original SNAREs as well as others with unusual localisation. This study also presented the intracellular localisation of the L. major SNAREs from the Qa group and reveals that these proteins could be useful as organelle markers in this parasitic protozoon.
Selection of housekeeping genes for gene expression studies in human reticulocytes using real-time PCR
Authors: Silver Nicholas , Best Steve , Jiang Jie , Thein Swee Lay
Published: October 2006

Background

Control genes, which are often referred to as housekeeping genes, are frequently used to normalise mRNA levels between different samples. However, the expression level of these genes may vary among tissues or cells and may change under certain circumstances. Thus, the selection of housekeeping genes is critical for gene expression studies. To address this issue, 7 candidate housekeeping genes including several commonly used ones were investigated in isolated human reticulocytes. For this, a simple ΔCt approach was employed by comparing relative expression of 'pairs of genes' within each sample. On this basis, stability of the candidate housekeeping genes was ranked according to repeatability of the gene expression differences among 31 samples.

Results

Initial screening of the expression pattern demonstrated that 1 of the 7 genes was expressed at very low levels in reticulocytes and was excluded from further analysis. The range of expression stability of the other 6 genes was (from most stable to least stable): GAPDH (glyceraldehyde 3-phosphate dehydrogenase), SDHA (succinate dehydrogenase), HPRT1 (hypoxanthine phosphoribosyl transferase 1), HBS1L (HBS1-like protein) and AHSP (alpha haemoglobin stabilising protein), followed by B2M (beta-2-microglobulin).

Conclusion

Using this simple approach, GAPDH was found to be the most suitable housekeeping gene for expression studies in reticulocytes while the commonly used B2M should be avoided.
Effects of THBS3, SPARC and SPP1 expression on biological behavior and survival in patients with osteosarcoma
Authors: Dalla-Torre Cristiane A , Yoshimoto Maisa , Lee Chung-Hae , Joshua Anthony M , de Toledo Silvia RC , Petrilli Antônio S , Andrade Joyce AD , Chilton-MacNeill Susan , Zielenska Maria , Squire Jeremy A
Published: October 2006

Background

Osteosarcoma is a very aggressive tumor with a propensity to metastasize and invade surrounding tissue. Identification of the molecular determinants of invasion and metastatic potential may guide the development of a rational strategy for devising specific therapies that target the pathways leading to osteosarcoma.

Methods

In this study, we used pathway-focused low density expression cDNA arrays to screen for candidate genes related to tumor progression. Expression patterns of the selected genes were validated by real time PCR on osteosarcoma patient tumor samples and correlated with clinical and pathological data.

Results

THBS3, SPARC and SPP1 were identified as genes differentially expressed in osteosarcoma. In particular, THBS3 was expressed at significantly high levels (p = 0.0001) in biopsies from patients with metastasis at diagnosis, which is a predictor of worse overall survival, event-free survival and relapse free survival at diagnosis. After chemotherapy, patients with tumors over-expressing THBS3 have worse relapse free survival. High SPARC expression was found in 51/55 (96.3%) osteosarcoma samples derived from 43 patients, and correlated with the worst event-free survival (p = 0.03) and relapse free survival (p = 0.07). Overexpression of SPP1 was found in 47 of 53 (89%) osteosarcomas correlating with better overall survival, event-free survival and relapse free survival at diagnosis.

Conclusion

In this study three genes were identified with pattern of differential gene expression associated with a phenotypic role in metastasis and invasion. Interestingly all encode for proteins involved in extracellular remodeling suggesting potential roles in osteosarcoma progression. This is the first report on the THBS3 gene working as a stimulator of tumor progression. Higher levels of THBS3 maintain the capacity of angiogenesis. High levels of SPARC are not required for tumor progression but are necessary for tumor growth and maintenance. SPP1 is not necessary for tumor progression in osteosarcoma and may be associated with inflammatory response and bone remodeling, functioning as a good biomarker.
Internal medicine specialists' attitudes towards working part-time: a comparison between 1996 and 2004
Authors: Lugtenberg Marjolein , Heiligers Phil JM , de Jong Judith D , Hingstman Lammert
Published: October 2006

Background

Although medical specialists traditionally hold negative views towards working part-time, the practice of medicine has evolved. Given the trend towards more part-time work and that there is no evidence that it compromises the quality of care, attitudes towards part-time work may have changed as well in recent years. The aim of this paper was to examine the possible changes in attitudes towards part-time work among specialists in internal medicine between 1996 and 2004. Moreover, we wanted to determine whether these attitudes were associated with individual characteristics (age, gender, investments in work) and whether attitudes of specialists within a partnership showed more resemblance than specialists' attitudes from different partnerships.

Methods

Two samples were used in this study: data of a survey conducted in 1996 and in 2004. After selecting internal medicine specialists working in general hospitals in The Netherlands, the sample consisted of 219 specialists in 1996 and 363 specialists in 2004. They were sent a questionnaire, including topics on the attitudes towards part-time work.

Results

Internal medicine specialists' attitudes towards working part-time became slightly more positive between 1996 and 2004. Full-time working specialists in 2004 still expressed concerns regarding the investments of part-timers in overhead tasks, the flexibility of task division, efficiency, communication and continuity of care. In 1996 gender was the only predictor of the attitude, in 2004 being a full- or a part-timer, age and the time invested in work were associated with this attitude. Furthermore, specialists' attitudes were not found to cluster much within partnerships.

Conclusion

In spite of the increasing number of specialists working or preferring to work part-time, part-time practice among internal medicine specialists seems not to be fully accepted. The results indicate that the attitudes are no longer gender based, but are associated with age and work aspects such as the number of hours worked. Though there is little evidence to support them, negative ideas about the consequences of part-time work for the quality of care still exist. Policy should be aimed at removing the organisational difficulties related to part-time work and create a system in which part-time practice is fully integrated and accepted.
The difficult doctor? Characteristics of physicians who report frustration with patients: an analysis of survey data
Authors: Krebs Erin E , Garrett Joanne M , Konrad Thomas R
Published: October 2006

Background

Literature on difficult doctor-patient relationships has focused on the "difficult patient." Our objective was to determine physician and practice characteristics associated with greater physician-reported frustration with patients.

Methods

We conducted a secondary analysis of the Physicians Worklife Survey, which surveyed a random national sample of physicians. Participants were 1391 family medicine, general internal medicine, and medicine subspecialty physicians. The survey assessed physician and practice characteristics, including stress, depression and anxiety symptoms, practice setting, work hours, case-mix, and control over administrative and clinical practice. Physicians estimated the percentage of their patients who were "generally frustrating to deal with." We categorized physicians by quartile of reported frustrating patients and compared characteristics of physicians in the top quartile to those in the other three quartiles. We used logistic regression to model physician characteristics associated with greater frustration.

Results

In unadjusted analyses, physicians who reported high frustration with patients were younger (p < 0.001); worked more hours per week (p = 0.041); and had more symptoms of depression, stress, and anxiety (p < 0.004 for all). In the final model, factors independently associated with high frustration included age < 40 years, work hours > 55 per week, higher stress, practice in a medicine subspeciality, and greater number of patients with psychosocial problems or substance abuse.

Conclusion

Personal and practice characteristics of physicians who report high frustration with patients differ from those of other physicians. Understanding factors contributing to physician frustration with patients may allow us to improve the quality of patient-physician relationships.
Validation of the Provincial Transfer Authorization Centre database: a comprehensive database containing records of all inter-facility patient transfers in the province of Ontario
Authors: Robinson Victoria A , MacDonald Russell D , Manuel Doug , Goel Vivek
Published: October 2006

Background

The Provincial Transfer Authorization Centre (PTAC) was established as a part of the emergency response in Ontario, Canada to the Severe Acute Respiratory Syndrome (SARS) outbreak in 2003. Prior to 2003, data relating to inter-facility patient transfers were not collected in a systematic manner. Then, in an emergency setting, a comprehensive database with a complex data collection process was established. For the first time in Ontario, population-based data for patient movement between healthcare facilities for a population of twelve million are available. The PTAC database stores all patient transfer data in a large database. There are few population-based patient transfer databases and the PTAC database is believed to be the largest example to house this novel dataset. A patient transfer database has also never been validated. This paper presents the validation of the PTAC database.

Methods

A random sample of 100 patient inter-facility transfer records was compared to the corresponding institutional patient records from the sending healthcare facilities. Measures of agreement, including sensitivity, were calculated for the 12 common data variables.

Results

Of the 100 randomly selected patient transfer records, 95 (95%) of the corresponding institutional patient records were located. Data variables in the categories patient demographics, facility identification and timing of transfer and reason and urgency of transfer had strong agreement levels. The 10 most commonly used data variables had accuracy rates that ranged from 85.3% to 100% and error rates ranging from 0 to 12.6%. These same variables had sensitivity values ranging from 0.87 to 1.0.

Conclusion

The very high level of agreement between institutional patient records and the PTAC data for fields compared in this study supports the validity of the PTAC database. For the first time, a population-based patient transfer database has been established. Although it was created during an emergency situation and data collection is dependent on front-line medical workers, the PTAC data has achieved a high level of validity, perhaps even higher than many purpose built databases created during non-emergency settings.
Evaluation of the acquired immune responses to Plasmodium vivax VIR variant antigens in individuals living in malaria-endemic areas of Brazil
Authors: Oliveira Tatiane R , Fernandez-Becerra Carmen , Jimenez Maria Carolina S , Del Portillo Hernando A , Soares Irene S
Published: October 2006

Background

The naturally-acquired immune response to Plasmodium vivax variant antigens (VIR) was evaluated in individuals exposed to malaria and living in different endemic areas for malaria in the north of Brazil.

Methods

Seven recombinant proteins representing four vir subfamilies (A, B, C, and E) obtained from a single patient from the Amazon Region were expressed in Escherichia coli as soluble glutathione S-transferase fusion proteins. The different recombinant proteins were compared by ELISA with regard to the recognition by IgM, IgG, and IgG subclass of antibodies from 200 individuals with patent infection.

Results

The frequency of individuals that presented antibodies anti-VIR (IgM plus IgG) during the infection was 49%. The frequencies of individuals that presented IgM or IgG antibodies anti-VIR were 29.6% or 26.0%, respectively. The prevalence of IgG antibodies against recombinant VIR proteins was significantly lower than the prevalence of antibodies against the recombinant proteins representing two surface antigens of merozoites of P. vivax: AMA-1 and MSP119 (57.0% and 90.5%, respectively). The cellular immune response to VIR antigens was evaluated by in vitro proliferative assays in mononuclear cells of the individuals recently exposed to P. vivax. No significant proliferative response to these antigens was observed when comparing malaria-exposed to non-exposed individuals.

Conclusion

This study provides evidence that there is a low frequency of individuals responding to each VIR antigens in endemic areas of Brazil. This fact may explain the host susceptibility to new episodes of the disease.
Ultrasound absorption and entropy production in biological tissue: a novel approach to anticancer therapy
Authors: Luo Liaofu , Molnar Joseph , Ding Hui , Lv Xiaogui , Spengler Gabriella
Published: October 2006

The entropy production of tumorous cells is higher than that of normal cells, and entropy flow is therefore directed from tumorous toward healthy cells. This results in information concerning the cancer propagating into the surrounding normal tissue. However, ultrasound absorption results in additional entropy production in tissues. The entropy mechanism possibly provides a basis for a novel approach to anticancer therapy through the use of ultrasound irradiation.

Methods

Through the calculation of ultrasound-induced entropy production and comparison of the theoretical results with the experimental data on ultrasound absorption in biological tissues, we have demonstrated that ultrasound absorption will increase the entropy in normal tissue more efficiently than in tumorous tissue due to the more acidic nature of the latter. Consequently, the direction of entropy flow between these two kinds of cells may be reversed on exposure to ultrasound.

Conclusion

The higher entropy accumulation of normal cells during ultrasound irradiation may possibly lead to a change in the original direction of entropy flow and avoid the propagation of information on the cancer into the normal tissues. We suggest that low-intensity, low-frequency ultrasound irradiation may be an efficient tool for the therapy of solid tumors.
Double valve replacement for acute spontaneous left chordal rupture secondary to chronic aortic incompetence
Authors: Agarwala Sandeep , Kumar Sanjay , Berridge John , McLenachan Jim , O'Regan David J
Published: October 2006

A 54 years old male with undiagnosed chronic calcific degenerative aortic valve incompetence presented with acute left anterior chordae tendinae rupture resulting in severe left heart failure and cardiogenic shock. He was successfully treated with emergency double valve replacement using mechanical valves. The pathogenesis of acute rupture of the anterior chordae tendinae, without any evidence of infective endocarditis or ischemic heart disease seems to have been attrition of the subvalvular mitral apparatus by the chronic regurgitant jet of aortic incompetence with chronic volume overload. We review the literature with specific focus on the occurrence of this unusual event.
Molecular and Pathologic Aspects of Endometrial Carcinogenesis
Authors: Hecht Jonathan L. , Mutter George L.
Published: October 2006

Endometrial cancer is the most common gynecological malignancy, with 41,000 new cases projected in the United States for 2006. Two different clinicopathologic subtypes are recognized: the estrogen-related (type I, endometrioid) and the non–estrogen-related types (type II, nonendometrioid such as papillary serous and clear cell). The morphologic differences in these cancers are mirrored in their molecular genetic profile with type I showing defects in DNA-mismatch repair and mutations in PTEN, K-ras, and beta-catenin, and type II showing aneuploidy and p53 mutations. This article reviews the genetic aspects of endometrial carcinogenesis and progression. We will define the precursor lesion of type I endometrioid cancer and the role of genetics and estrogen in its progression.
Estrogen Modulation of MgATPase Activity of Nonmuscle Myosin-II-B Filaments
Authors: Gorodeski George I.
Published: October 2006

The study tested the hypothesis that estrogen controls epithelial paracellular resistance through modulation of myosin. The objective was to understand how estrogen modulates nonmuscle myosin-II-B (NMM-II-B), the main component of the cortical actomyosin in human epithelial cervical cells. Experiments used human cervical epithelial cells CaSki as a model, and end points were NMM-II-B phosphorylation, filamentation, and MgATPase activity. The results were as follows: 1) treatment with estrogen increased phosphorylation and MgATPase activity and decreased NMM-II-B filamentation; 2) estrogen effects could be blocked by antisense nucleotides for the estrogen receptor-α and by ICI-182,780, tamoxifen, and the casein kinase-II (CK2) inhibitor, 5,6-dichloro-1-β-(D)-ribofuranosylbenzimidazole and attenuated by AG1478 and PD98059 (inhibitors of epithelial growth factor receptor and ERK/MAPK) but not staurosporine [blocker of protein kinase C (PKC)]; 3) treatments with the PKC activator sn-1,2-dioctanoyl diglyceride induced biphasic effect on NMM-II-B MgATPase activity: an increase at 1 nm to 1 μm and a decrease in activity at more than 1 μm; 4) sn-1,2-dioctanoyl diglyceride also decreased NMM-II-B filamentation in a monophasic and saturable dose dependence (EC50 1–10 μm); 5) when coincubated directly with purified NMM-II-B filaments, both CK2 and PKC decreased filamentation and increased MgATPase activity; 6) assays done on disassembled NMM-II-B filaments showed MgATPase activity in filaments obtained from estrogen-treated cells but not estrogen-depleted cells; and 7) incubations in vitro with CK2, but not PKC, facilitated MgATPase activity, even in disassembled NMM-II-B filaments. The results suggest that estrogen, in an effect mediated by estrogen receptor-α and CK2 and involving the epithelial growth factor receptor and ERK/MAPK cascades, increases NMM-II-B MgATPase activity independent of NMM-II-B filamentation status.
Inactivation of Signal Transducer and Activator of Transcription 3 in Proopiomelanocortin (Pomc) Neurons Causes Decreased Pomc Expression, Mild Obesity, and Defects in Compensatory Refeeding
Authors: Xu Allison W. , Ste-Marie Linda , Kaelin Christopher B. , Barsh Gregory S.
Published: October 2006

Leptin is an adipocyte-derived hormone that signals body energy status to the brain by acting on multiple neuronal subgroups in the hypothalamus, including those that express proopiomelanocortin (Pomc) and agouti-related protein (Agrp). Signal transducer and activator of transcription 3 (Stat3) is an important intracellular signaling molecule activated by leptin, and previous studies have shown that mice carrying a mutated leptin receptor that abolished Stat3 binding are grossly obese. To determine the extent to which Stat3 signaling in Pomc neurons was responsible for these effects, we constructed Pomc-specific Stat3 mutants using a Cre recombinase transgene driven by the Pomc promoter. We find that Pomc expression is diminished in the mutant mice, suggesting that Stat3 is required for Pomc transcription. Pomc-specific Stat3 female mutant mice exhibit a 2-fold increase in fat pad mass but only a slight increase in total body weight. Mutant mice remain responsive to leptin-induced hypophagia and are not hypersensitive to a high-fat diet; however, mutant mice fail to mount a normal compensatory refeeding response. These results demonstrate a requirement for Stat3 in transcriptional regulation of Pomc but indicate that this circuit is only one of several components that underlie the neuronal response to leptin and the role of Stat3 in that response.
RETRACTED: Computation of solidification of Al-4.5% Cu alloy casting cast in CO2-sand mould
Authors: Kulkarni S N , Radhakrishna K
Published: October 2006

RETRACTED
Experimental and finite element analysis to predict the dimensional changes of a cold-forged spur gear
Authors: Lee Youngseon , Kwon Yongnam , Lee Junghwan , Ishikawa Takashi
Published: October 2006

The dimensional tolerance of spur gears for automobiles is within the range of several micrometres. Therefore, to manufacture these gears by cold forging, dimensions should be controlled in the same range. The dimensional changes by the various forging variables should be analysed and compensated into the forging tool. Computer-aided engineering (CAE) would be appropriate for investigating the effects of variables. However, the realistic finite element modelling (FEM) techniques should be confirmed and used to predict the dimension of the forged part in the order of micrometres. As realistic modelling considers the elastic characteristics of both workpiece and die at unloading and ejecting stage, threedimensional analysis for spur gears may often encounter difficulties in solving time and convergence. In this study, dimensional changes for cold-forged parts of spur gears were investigated by experimental and FEM analysis, after modelling to obtain desirable FEM results had been studied by closed-die upsetting. The dimensional changes of involute curve for the spur gear can be analysed from the FEM results during the whole forging stage; and give an index of a modified involute curve of the forging tool for improving gear profile accuracy.
Turning of particulate metal matrix composites — review and discussion
Authors: Basavarajappa S , Chandramohan G , Rao K V Narasimha , Radhakrishanan R , Krishnaraj V
Published: October 2006

Metal matrix composites (MMCs) have emerged as an important class of materials, which are increasingly being utilized in recent years. Application of these materials in certain areas is limited due to difficulties in machining. The principal machining parameters that control machinability characteristics are extrinsic parameters (cutting speed, feed rate, depth of cut, and type of cutting tools) and intrinsic parameters (particulate size, volume fraction, and type of reinforcement). Different cutting tools used in machining these materials are given in the order of decreasing hardness as PCD, CBN, TiC, Si3N4, Al2O3, and WC. The present review is focused on the influence of cutting parameters, morphology, distribution, and volume fraction of reinforcement on the surface finish, tool life, cutting forces, and chip formation. This review will provide an insight into selecting the optimum machining parameters for machining metal matrix composites.
An experimental investigation on the effect of powder mixed dielectric on machining performance in electric discharge machining
Authors: Çogun C , Özerkan B , Karaçay T
Published: October 2006

In this study, the variations of machining performance outputs, namely workpiece surface roughness, surface profile power spectral density, workpiece removal rate, electrode wear rate, relative wear, workpiece surface hardness, and workpiece surface microstructure were experimentally investigated with the varying machining parameters for metal powder mixed dielectric liquid in electrical discharge machining (EDM). The machining tests were conducted by using a prismatic steel workpiece and copper electrodes with graphite and boric acid powders (H3BO3) mixed kerosene dielectric at different powder concentrations and pulse time settings. The experiments have shown that the type and concentration of the powders mixed into the dielectric and the pulse time were effective on machining performance outputs in EDM.
Incorporating fractional backordering in the multi-product manufacturing situation with shelf-lives
Authors: Sharma S
Published: October 2006

In previous research, shortages have been included in the multi-product manufacturing situation with shelf-lives. The assumption that all the shortages would be completely backordered is relaxed in the present work. A fraction of shortage quantity is not backordered and the analysis is extended using the common cycle time approach. Shelf-life and manufacturing capacity constraints are imposed. A simple numerical example is provided to illustrate the mathematical formulation.
Geometrical mapping for a triangular element. Part 1: Optimal blank design
Authors: Shim Hyun Bo
Published: October 2006

An inverse mosaic method, a geometric mapping for a triangular element followed by mesh smoothing, has been proposed. The main difference between this and the original geometric mapping method lies in the type of element by which the final deformed shape is defined. In fact, the quadrilateral element is less dexterous than the triangular element for a description of surface shape, and describable surface shape using only the quadrilateral element is quite limited. Because of this problem, original geometrical mapping has limited applications to relatively simple shapes. Since the present inverse mosaic method is based on the triangular element, the method is applicable to most surfaces regardless of the complexity of the shape. Moreover, polygons can be divided into several pieces of triangles; the method can be applied to the finite element mesh system generated by a mesh generator, where quadrilateral elements and triangular elements are mixed together. Accuracy and dependence on the order of determination are also significant problems. In the inverse mosaic method, the accuracy has been improved markedly through smoothing after mapping, sufficient for it to be used for the actual problems, e.g. trim-line design. In spite of these marked improvements, the accuracy is basically limited, especially when the involved deformation mode is mainly by drawing or stretching, rather than bending, since deformation behaviour has not been accounted for. In general, the accuracy of an iterative scheme is better than the retromarching scheme, e.g. geometric mapping for optimal blank design; however, the method requires an initial guess to start the iterative sequence. Both the accuracy and the initial guess generation have been solved by combining the present inverse mosaic method and the radius vector method, a kind of iterative method. The efficiency has been verified through deep-drawing examples.
Geometrical mapping for a triangular element. Part 2: Trimming-line design for flanging operation
Authors: Shim Hyun Bo
Published: October 2006

A flanging operation in stamping is basically a bending operation that bends the edge of a part for several purposes. Flanging with a curved bending line causes in-plane deformation, although not significant, in contrast with straight-line bending, which is the development method that is widely used in the stamping industries and usually fails to predict an accurate trimming line. Since the inverse mosaic method generally provides a good prediction when the in-plane deformation is insignificant, the inverse mosaic method can be used as a trimming design tool. As the shape of the stamped part is three-dimensional in general, the original inverse mosaic method which maps a three-dimensional shape on to a two-dimensional plane has been extended to the mapping of three-dimensional shapes by the introduction of a contact algorithm. By mapping the target shape, i.e. the desired shape after trimming, on to the first stamped shape, the trimmed shape after the first stamping can be obtained. The validity of the current method has been verified through an actual front-fender example.
Temperature simulation of the preheating period in friction stir welding based on the finite element method
Authors: Zhang H , Huang J H , Lin S B , Wu L , Zhang J G
Published: October 2006

In this paper, a thermal history and distribution analysis of the preheating period of friction stir welding (FSW) of AZ31 magnesium alloy using the finite element method is presented. A moving heat source along the thickness is used to simulate the plunge movement of the pin and the heat flux generated by the friction between the pin and the workpiece is applied as volume heat. Temperature history and distributions at different plunge speeds and rotational speeds are simulated and measured to determine the appropriate preheating parameters. When a rotational speed of 600 r/min and a plunge speed of 3mm/min are used, the maximum preheating temperature can reach to about 450°C, showing that the heat generated by the pin cannot be neglected during FSW and the heat proportion is about 15 per cent of the total heat generated by the tool (including generated by the shoulder and the pin). The high temperature is in the range of the pin diameter and the maximum temperature gradient is on the boundary of the pin. The simulation temperature results corresponded well with the measured temperature during experiments.
A study on the hot tearing in AL-1% Sn cast alloys
Authors: Datta G L , Karunakar D B
Published: October 2006

Hot tearing in certain cast metals continues to bother metal casters. A number of casting parameters such as pouring temperature and extent of grain refinement affect the susceptibility to hot tearing. Published literature seems to be incomplete or conflicting in this regard. The present work involves experimental investigations with an objective of determining conditions under which hot tearing can be eliminated.

Experiments were conducted on Al-1% Sn alloys. Al-1% Sn is a high-freezing-range alloy known to be extremely prone to hot tear cracking. Effects of pouring temperature, grain refinement, and presence of Fe and Ni have been investigated by making use of a ring type casting with a steel core. Al-5Ti-1B was used as the grain refiner. Optical and scanning electron microscopy (SEM) was used in the study. The results showed that contrary to some published work, grain refinement alone could not eliminate hot tearing. Average hot tear length decreased with increased grain refinement and the minimum achieved was at 5 per cent by weight of Al-5Ti-1B addition. Both Fe and Ni have positive effects in minimizing hot tear formation. However, no correlation could be noted between secondary dendritic arm spacing and hot tearing tendency. SEM studies have shown that with Fe there is an Al-Sn-Fe-rich phase in the form of a leaf-like structure, which is believed to provide anchorage to the adjacent grains and thus overcome hot tear.
Mobile robotic platform controller with an effective data communication protocol
Authors: Onwubolu G C , Jannif I , Tazil M , Singh A
Published: October 2006

The current paper presents the design, implementation, and experimental results of the motion controller design of an effective data communication mobile robot platform developed for independently controlling each robotic drive wheel. The main objective of the research was to determine the data communication efficiency based on a three-wire bus, n-bit serial latched data communication system for independently controlling the closed-loop motion of each robotic wheel without the inclusion of a line tracer sensor unit on a robot. Odometry test results show that the motion controller model proposed is effective for applications in an automated guided vehicle used in manufacturing facilities.
New mechanical treatment for chemical pulp
Authors: Kang T , Paulapuro H
Published: October 2006

This study presents a new method to modify chemical pulp mechanically using an ultra-fine friction grinder, which works in a different way compared with conventional refiners. It consists of two grinding stones: a lower rotating one and an upper stationary one. The pulp passing through the gap between the stone plates is subjected to compressive and shear forces.

The results showed that the gap clearance of the grinder plays an important role in controlling the fibrillation of fibres and the specific energy. External fibrillation became a dominant effect at a larger gap, whereas internal fibrillation developed faster at a smaller gap. Fibres were modified mostly into fibrils at a much smaller gap. Scott bond strength of pulps treated in the grinder was better than that of Valley-beaten pulps. Pulp properties can be varied by adjusting the pulp consistency, rotating speed, grit size, the dullness of the plate surface, and the number of pulp recirculations.
Experimental studies of heat transfer in a tube bundle model
Authors: Liu L , Choudhury T. H. , Hu B , Duggan N. K. , Richardson S. M. , Hewitt G. F.
Published: October 2006

In this article, both numerical and experimental results are presented for heat transfer within subsea tube bundles. Computational fluid dynamic (CFD) calculations were performed to develop correlations for the Nusselt numbers at various tube surfaces. To validate the CFD calculations, experimental studies were implemented in a water-filled tube bundle. The experimental system consisted of one heating tube and two production tubes, the three tubes being mounted on a carrier tube with the space between the tubes being filled with water. The predicted Nusselt numbers, taking account of interaction effects, agreed with the experimental data for the carrier tube and the lower production tube. The experimental heat losses from the production tubes and the heating tube are ∼ 10 per cent higher than those predicted.
Revenue Management of a Make-to-Stock Queue
Authors: Caldentey René , Wein Lawrence M.
Published: October 2006

Motivated by recent electronic marketplaces, we consider a single-product make-to-stock manufacturing system that uses two alternative selling channels: long-term contracts and a spot market of electronic orders. At time 0, the risk-averse manufacturer selects the long-term contract price, at which point buyers choose one of the two channels. The resulting long-term contract demand is a deterministic fluid, while the spot-market demand is modeled as a stochastic renewal process. An exponential reflected random walk model is used to model the spot-market price, which is correlated with the spot-market demand process. The manufacturer accepts or rejects each electronic order, and long-term contracts and accepted electronic orders are backordered if necessary. The manufacturer’s control problem is to select the optimal long-term contract price as well as the optimal production (i.e., busy/idle) and electronic-order admission policies to maximize revenue minus inventory holding and backorder costs. Under heavy-traffic conditions, the problem is approximated by a diffusion-control problem, and analytical approximations are used to derive a policy that is simple, and reasonably accurate and robust.
Revenue Management for a Multiclass Single-Server Queue via a Fluid Model Analysis
Authors: Maglaras Constantinos
Published: October 2006

Motivated by the recent adoption of tactical pricing strategies in manufacturing settings, this paper studies a problem of dynamic pricing for a multiproduct make-to-order system. Specifically, for a multiclass Mn/M/1 queue with controllable arrival rates, general demand curves, and linear holding costs, we study the problem of maximizing the expected revenues minus holding costs by selecting a pair of dynamic pricing and sequencing policies. Using a deterministic and continuous (fluid model) relaxation of this problem, which can be justified asymptotically as the capacity and the potential demand grow large, we show the following: (i) greedy sequencing (i.e., the cμ-rule) is optimal, (ii) the optimal pricing and sequencing decisions decouple in finite time, after which (iii) the system evolution and thus the optimal prices depend only on the total workload. Building on (i)–(iii), we propose a one-dimensional workload relaxation to the fluid pricing problem that is simpler to analyze, and leads to intuitive and implementable pricing heuristics. Numerical results illustrate the near-optimal performance of the fluid heuristics and the benefits from dynamic pricing.
Dynamic Control of a Multiclass Queue with Thin Arrival Streams
Authors: Ata Barış
Published: October 2006

As a model of make-to-order production, we consider an admission control problem for a multiclass, single-server queue. The production system serves multiple demand streams, each having a rigid due-date lead time. To meet the due-date constraints, a system manager may reject orders when a backlog of work is judged to be excessive, thereby incurring lost revenues. The system manager strives to minimize long-run average lost revenues by dynamically making admission control and sequencing decisions. Under heavy-traffic conditions the scheduling problem is approximated by a Brownian control problem, which is solved explicitly. Interpreting this solution in the context of the original queueing system, a nested threshold policy is proposed. A simulation experiment is performed to demonstrate the effectiveness of this policy.
Evaluating Academic Programs: With Applications to U.S. Graduate Decision Science Programs
Authors: Keeney Ralph L. , See Kelly E. , von Winterfeldt Detlof
Published: October 2006

This paper describes a decision analysis methodology to evaluate academic programs. It avoids the shortcomings of the well-known evaluations of universities and academic programs produced by the public media. In addition to evaluating traditional departments and schools, the methodology is designed to evaluate interdisciplinary programs or fields that typically span many areas of a university, such as operations research, risk analysis, and decision science. We first discuss general principles of using this methodology for the evaluation of disciplinary or interdisciplinary academic programs. Next, we apply this methodology to interdisciplinary graduate decision science programs in United States universities, focusing on both prescriptive decision analysis and descriptive decision research. Finally, we suggest how the methodology might be implemented to evaluate operations research programs.
Iatrogenic facial nerve injury during otologic surgery
Authors: Green J. Douglas , Shelton Clough , Brackmann Derald E.
Published: October 2006

Perhaps the most devastating complication in otologic surgery is that of inadvertent injury to the facial nerve. A review of 22 patients who had sustained an iatrogenic facial nerve injury was conducted. Although the most common procedure being performed during the injury was mastoidectomy (55%), a surprising number of patients had injury during tympanoplasty (14%) or during removal of exostoses (14%). The most common area of injury to the facial nerve in this series was in the tympanic segment. In 79% of the patients, the facial nerve injury was not detected at the time of surgery. All patients underwent surgical exploration of the facial nerve. Otologic surgeons are cautioned to be familiar with the normal course of the facial nerve and to be aware of the potential for facial nerve injury when performing transcanal surgery.
Toxic shock syndrome after functional endonasal sinus surgery: An all or none phenomenon?
Authors: Abram Adam C. , Bellian Kenneth T. , Giles William J. , Gross Charles W.
Published: October 2006

Reported cases of toxic shock syndrome (TSS) following nasal surgery or functional endonasal sinus surgery (FESS) are uncommon. Classic TSS is a serious multisystem disorder resulting from Staphylococcus aureus phage I toxic shock syndrome toxin 1 (TSST‐1), and it is characterized by fever, rash, hypotension, mucosal hyperemia, vomiting, diarrhea, and laboratory evidence of multisystem organ dysfunction. TSS cases following nasal surgery have been associated with nasal packing, mucosal barrier violation, prior S aureus phage I colonization, as well as low antitoxin antibody levels.1

Of the 1700 FESS procedures performed at our institution, 3 cases were complicated by classic TSS, with 2 additional patients having a postsurgical course compromised by a milder degree of TSS. Diagnostic criteria, clinical presentation, management, and etiology are discussed, and the possibility of a continuum from mild‐to‐classic TSS is addressed.
Phenytoin for motion sickness: Clinical evaluation
Authors: Knox Glenn W. , Woodard Daniel , Chelen William , Ferguson Robin , Johnson Linda
Published: October 2006

Phenytoin has previously been shown to protect against motion sickness induced by Coriolis stimulation. The purpose of our series of investigations was to investigate further the efficacy of phenytoin for motion sickness prophylaxis and to gain insight into its mechanism of action. We tested participants with electronystagmography, off‐vertical rotation, sea travel, and parabolic flight after they received phenytoin or placebo. Blood levels of at least 9 μg/mL were found to protect against motion sickness. Electronystagmography showed significant decreases in the gain of the vestibuloocular reflex in participants receiving phenytoin. Few side effects were seen with drug levels in the 9 to 15 μg/mL range. Phenytoin is an effective motion sickness countermeasure that may exert its effect through a combination of central nervous system and peripheral vestibular effects.
Factors affecting survival of patients with tumors of the anterior skull base
Authors: Mccaffrey Thomas V. , Olsen Kerry D. , Yohanan James M. , Lewis Jean E. , Ebersold Michael J. , Piepgras David G.
Published: October 2006

Fifty‐four patients with primary neoplasms of the anterior skull base were treated by craniofacial resection with curative intent. The most common tumor was esthesioneuroblastoma (24), followed by squamous cell carcinoma (10). The overall 2‐year and 5‐year survivals were 75% and 49%, respectively. High‐grade tumors, grades 3 and 4, had a poorer prognosis. Tumor size, dural involvement, sphenoid sinus involvement, age, and sex had no significant influence on survival when examined by multivariate survival analysis. Sixteen complications were noted in the postoperative period. Cerebrospinal fluid leakage occurred in 2 patients and loss of frontal bone occurred in 4. There were no operative or perioperative deaths. Craniofacial resection permits surgical resection of the majority of anterior skull base tumors with acceptable morbidity.
Evaluation of four new carbocyanine dyes for photodynamic therapy with lasers
Authors: Lipshutz Gerald S. , Castro Dan J. , Saxton Romaine E. , Haugland Richard P. , Soudant Jacque
Published: October 2006

The search for improved photosensitizers for laser phototherapy of malignancies has led to the examination of a new group of carbocyanine dyes as effective fluorochromes. In this study, four carbocyanine dyes with different absorption maxima of 483 nm [DiOC6(3)], 545.5 nm (DiIC5(3)], 556.6 nm [DiSC5(3)], and 651.0 nm [DiSC3(5)] were tested in vitro. The kinetics of uptake and toxicity of these four dyes were assessed for P3 human squamous cell carcinoma, HT29 colon carcinoma, M26 melanoma, and TE671 fibrosarcoma cell lines at 15, 30, 45, 60, and 180 minutes after exposure with each dye. After sensitization with DiOC6(3), the P3 and M26 cell lines were also tested for phototherapy by treatment with 488‐nm light from an argon laser. The results showed that these four carbocyanine dyes had rapid and significant uptake by the carcinoma cell lines with no toxicity at concentrations <0.1 μg/mL. Nontoxic DiOC6(3) levels in sensitized tumor cells after laser phototherapy resulted in ∼85% inhibition of P3 and ∼95% inhibition of M26 cell lines by MTT assays. The results suggest that these carbocyanine dyes can be used for tumor photosensitization and wavelength‐matched laser photodynamic therapy. Further in vivo studies will be necessary to define the clinical potential of carbocyanine dyes as tumor‐targeting agents for phototherapy of cancer.
Speech recognition in patients after successful surgery for unilateral congenital ear anomalies
Authors: Snik Ad F. M. , Teunissen Bert , Cremers Cor W. R. J.
Published: October 2006

It is generally assumed that auditory stimulation since birth is important for the proper development of the central auditory nervous system. Whether auditory deprivation occurs in man and, therefore, whether it may be considered as a contraindication to surgery in unilateral congenital middle ear anomalies and atresias is the subject of the present study. Speech recognition during both monaural and binaural presentation was studied in patients who had successful surgery for a unilateral congenital ear anomaly.

In binaural speech recognition tests, the average results of the patient group (N = 13) and a group of subjects with normal hearing proved to be comparable. The average speech recognition score using monaurally presented band‐pass filtered speech was 84% ± 8% and 77% ± 10% for the unoperated (normal) and operated ears, respectively (statistically significant). Speech‐to‐noise ratios of ‐5.6 ± 0.7 dB and ‐3.9 ± 1.6 db were found in the normal and operated ears, respectively (statistically significant).

It is concluded that, in general, the speech recognition scores of the operated ears were satisfactory, but poorer than those of the normal ears.