bluuebunny/crossref_metadata_2025 huggingface dataset:
Modeling dose distributions from portal dose images using the convolution/superposition method
Authors: McNutt Todd R. , Mackie T. Rock , Reckwerdt Paul , Paliwal Bhudatt R.
Published: March 2003

Post‐treatment dose verification refers to the process of reconstructing delivered dose distributions internal to a patient from information obtained during the treatment. The exit dose is commonly used to describe the dose beyond the exit surface of the patient from a megavoltage photon beam. Portal imaging provides a method of determining the dose in a plane distal to a patient from a megavoltage therapeutic beam. This exit dose enables reconstruction of the dose distribution from external beam radiation throughout the patient utilizing the convolution/superposition method and an extended phantom. An iterative convolution/superposition algorithm has been created to reconstruct dose distributions in patients from exit dose measurements during a radiotherapy treatment. The method is based on an extended phantom that includes the patient CT representation and an electronic portal imaging device (EPID). The convolution/superposition method computes the dose throughout the extended phantom, which allows the portal dose image to be predicted in the EPID. The process is then reversed to take the portal dose measurement and infer what the dose distribution must have been to produce the measured portal dose. The dose distribution is modeled without knowledge of the incident intensity distribution, and includes the effects of scatter in the computation. The iterative method begins by assuming that the primary energy fluence (PEF) at the portal image plane is equal to the portal dose image, the PEF is then back‐projected through the extended phantom and convolved with the dose deposition kernel to determine a new prediction of the portal dose image. The image of the ratio of the computed PEF to the computed portal dose is then multiplied by the measured portal dose image to produce a better representation of the PEF. Successive iterations of this process then converge to the exiting PEF image that would produce the measured portal dose image. Once convergence is established, the dose distribution is determined by back‐projecting the PEF and convolving with the dose deposition kernel. The method is accurate, provided the patient representation during treatment is known. The method was used on three phantoms with a photon energy of 6 MV to verify convergence and accuracy of the algorithm. The reconstructed dose volumes agree to within 3% of the forward computation dose volumes. Furthermore, this technique assumes no prior knowledge of the incident fluence and therefore may better represent the dose actually delivered.
Surface dose measurements for highly oblique electron beams
Authors: Ostwald P. M. , Kron T.
Published: March 2003

Clinical applications of electrons may involve oblique incidence of beams, and although dose variations for angles up to 60° from normal incidence are well documented, no results are available for highly oblique beams. Surface dose measurements in highly oblique beams were made using parallel‐plate ion chambers and both standard LiF:Mg, Ti, and carbon‐loaded LiF Thermoluminescent Dosimeters (TLD). Obliquity factors (OBF) or surface dose at an oblique angle divided by the surface dose at perpendicular incidence, were obtained for electron energies between 4 and 20 MeV. Measurements were performed on a flat solid water phantom without a collimator at 100 cm SSD. Comparisons were also made to collimated beams. The OBFs of surface doses plotted against the angle of incidence increased to a maximum dose followed by a rapid dropoff in dose. The increase in OBF was more rapid for higher energies. The maximum OBF occurred at larger angles for higher‐energy beams and ranged from 73° for 4 MeV to 84° for 20 MeV. At the dose maximum, OBFs were between 130% and 160% of direct beam doses, yielding surface doses of up to 150% of Dmax for the 20 MeV beam. At 2 mm depth the dose ratio was found to increase initially with angle and then decrease as Dmax moved closer to the surface. A higher maximum dose was measured at 2 mm depth than at the surface. A comparison of ion chamber types showed that a chamber with a small electrode spacing and large guard ring is required for oblique dose measurement. A semiempirical equation was used to model the dose increase at the surface with different energy electron beams.
Computerized analysis for automated detection of lung nodules in digital chest radiographs
Authors: Xu Xin‐Wei
Published: March 2003

The objective of this study was to develop a computer‐aided diagnosis (CAD) scheme for automated detection of lung nodules in digital chest images in order to help radiologists to improve their performance in detecting lung nodules. Lung nodules in chest radiographs are the important sign of lung cancer which is the leading cause of cancer death in men and women in the United States, with the 5‐year survival rate only about 13%. Early detection and treatment are crucial for the improvement of this survival rate for patients with lung cancer. This dissertation included the following four topics: (1) accurate determination of ribcage boundary in digital chest radiographs; (2) detection of right and left hemidiaphragm edges and delineation of lung fields in digital chest radiographs; (3) development of a CAD scheme for automated detection of lung nodules in digital chest radiographs; and (4) ROC studies of effects of CAD output on radiologists' performance for detection of lung nodules on chest radiographs. Our CAD scheme for automated detection of lung nodules in digital chest images was based on the segmentation of lung fields, the difference image technique, image feature analysis, and an artificial neural network. The performance of the CAD scheme was evaluated by the FROC methodology. The CAD scheme achieved an improved performance of 70% sensitivity with 1.7 false positives per image, on average. The ROC analysis results indicated that radiologists increased their performance significantly in detecting lung nodules by use of the CAD output as a “second opinion.” Radiologists did not increase their reading time when the CAD output was used. [Thesis copies are available upon request from the author.]
R50 as a beam quality specifier for selecting stopping‐power ratios and reference depths for electron dosimetry
Authors: Burns D. T. , Ding G. X. , Rogers D. W. O.
Published: March 2003

For electron beam reference dosimetry in radiotherapy, it is shown that by choosing the reference depth as dref=0.6R50−0.1 cm, where R50 is the half‐value depth in centimeters, the Spencer–Attix water‐to‐air stopping‐power ratio at dref is given by =1.2534−0.1487 (R50)0.2144. This is derived from data for obtained from realistic Monte Carlo simulations for 24 clinical beams. The rms deviation of this expression from the Monte Carlo calculations is 0.16%, with a maximum deviation of 0.26%. This approach fully takes into account the spectral differences between real electron beams of the same R50 and allows an absorbed‐dose calibration at a standards laboratory to be easily and accurately transferred to a reference clinical beam. Using a single paraeter to specify , rather than the two parameters (R50 and depth) needed when the reference depth is chosen as the depth of dose maximum, has the potential to greatly simplify electron beam dosimetry protocols and allows the use of a similar formalism for photon and electron beam dosimetry. For use in converting a depth–ionization curve into a depth–dose curve, a somewhat less accurate but general expression for as a function of R50 and depth is presented.
Cerebral tumor volume calculations using planimetric and eigenimage analysis
Authors: Peck Donald J. , Windham Joe P. , Emery Linda L. , Soltanian‐Zadeh Hamid , Hearshen David O. , Mikkelsen Tom
Published: March 2003

Volume determination in cerebral tumors requires accurate and reproducible segmentation. This task has been traditionally accomplished using planimetric methods which define the boundary of the lesion using thresholding and edge detection schemes. These methods lack accuracy and reproducibility when the contrast between the lesion and surrounding tissue is not maximized. Because of this limitation contrast agents are used providing reproducible results for the enhancing portion of the lesion. A novel approach for volume determination has been developed (eigenimage filter) which segments a desired feature (tissue type) from surrounding undesired features in a sequence of images. This method corrects for partial volume effects and has been shown to provide accurate and reproducible volume determinations. In addition, the eigenimage filter does not require the use of contrast and has the capability to segment a lesion into multiple regions. This allows different components of the lesion to be included and monitored in treatment. In this study planimetric methods and the eigenimage filter were compared for segmenting cerebral tumors and determining their volumes. The planimetric methods were reproducible in determining volumes for the enhancing portion of the lesion with interobserver percent differences <8% and intraobserver percent differences <4%. The eigenimage filter had interobserver percent differences <7% and intraobserver percent differences <3%. In the eigenimage procedure both the enhancing portion of the lesion as well as additional regions within the lesion were identified. Comparing the results obtained from the two methods demonstrated good agreement for presurgical studies (percent differences <9%). When comparing postsurgical studies large differences were seen. In the postsurgical studies the eigenimage method allowed multiple regions to be followed in subsequent MRI and in two patients showed a volume change that suggested tumor recurrence more clearly. Since the amount of information obtained using the eigenimage filter may allow a more complete assessment of the lesion, it is suggested that it could improve the clinical evaluation of cerebral tumors.
Crystal Structure of the Carboxyltransferase Domain of Acetyl-Coenzyme A Carboxylase
Authors: Zhang Hailong , Yang Zhiru , Shen Yang , Tong Liang
Published: March 2003

Acetyl–coenzyme A carboxylases (ACCs) are required for the biosynthesis and oxidation of long-chain fatty acids. They are targets for therapeutics against obesity and diabetes, and several herbicides function by inhibiting their carboxyltransferase (CT) domain. We determined the crystal structure of the free enzyme and the coenzyme A complex of yeast CT at 2.7 angstrom resolution and found that it comprises two domains, both belonging to the crotonase/ClpP superfamily. The active site is at the interface of a dimer. Mutagenesis and kinetic studies reveal the functional roles of conserved residues here. The herbicides target the active site of CT, providing a lead for inhibitor development against human ACCs.
Identification of Hedgehog Pathway Components by RNAi in
Drosophila
Cultured Cells
Authors: Lum Lawrence , Yao Shenqin , Mozer Brian , Rovescalli Alessandra , Von Kessler Doris , Nirenberg Marshall , Beachy Philip A.
Published: March 2003

Classical genetic screens can be limited by the selectivity of mutational targeting, the complexities of anatomically based phenotypic analysis, or difficulties in subsequent gene identification. Focusing on signaling response to the secreted morphogen Hedgehog (Hh), we used RNA interference (RNAi) and a quantitative cultured cell assay to systematically screen functional roles of all kinases and phosphatases, and subsequently 43% of predicted
Drosophila
genes. Two gene products reported to function in Wingless (Wg) signaling were identified as Hh pathway components: a cell surface protein (Dally-like protein) required for Hh signal reception, and casein kinase 1α, a candidate tumor suppressor that regulates basal activities of both Hh and Wg pathways. This type of cultured cell–based functional genomics approach may be useful in the systematic analysis of other biological processes.
Reovirus σNS Protein Localizes to Inclusions through an Association Requiring the μNS Amino Terminus
Authors: Miller Cathy L. , Broering Teresa J. , Parker John S. L. , Arnold Michelle M. , Nibert Max L.
Published: March 2003

Cells infected with mammalian reoviruses contain phase-dense inclusions, called viral factories, in which viral replication and assembly are thought to occur. The major reovirus nonstructural protein μNS forms morphologically similar phase-dense inclusions when expressed in the absence of other viral proteins, suggesting it is a primary determinant of factory formation. In this study we examined the localization of the other major reovirus nonstructural protein, σNS. Although σNS colocalized with μNS in viral factories during infection, it was distributed diffusely throughout the cell when expressed in the absence of μNS. When coexpressed with μNS, σNS was redistributed and colocalized with μNS inclusions, indicating that the two proteins associate in the absence of other viral proteins and suggesting that this association may mediate the localization of σNS to viral factories in infected cells. We have previously shown that μNS residues 1 to 40 or 41 are both necessary and sufficient for μNS association with the viral microtubule-associated protein μ2. In the present study we found that this same region of μNS is required for its association with σNS. We further dissected this region, identifying residues 1 to 13 of μNS as necessary for association with σNS, but not with μ2. Deletion of σNS residues 1 to 11, which we have previously shown to be required for RNA binding by that protein, resulted in diminished association of σNS with μNS. Furthermore, when treated with RNase, a large portion of σNS was released from μNS coimmunoprecipitates, suggesting that RNA contributes to their association. The results of this study provide further evidence that μNS plays a key role in forming the reovirus factories and recruiting other components to them.
Human Cytomegalovirus Activates Inflammatory Cytokine Responses via CD14 and Toll-Like Receptor 2
Authors: Compton Teresa , Kurt-Jones Evelyn A. , Boehme Karl W. , Belko John , Latz Eicke , Golenbock Douglas T. , Finberg Robert W.
Published: March 2003

Human cytomegalovirus (CMV) is a ubiquitous opportunistic pathogen that causes significant morbidity and mortality in immuncompromised people. An understanding of how CMV induces and circumvents host immunity is of critical importance in efforts to design effective therapeutics. It was recently discovered that mere cell contact by CMV particles leads to profound modulation of cellular gene expression, including induction of inflammatory cytokines and interferon-stimulated genes characteristic of innate immune detection. These findings suggest that a membrane receptor recognizes a CMV envelope protein(s), leading to innate immune activation. Here, we show that the pattern recognition receptors Toll-like receptor 2 (TLR2) and CD14 recognize CMV virions and trigger inflammatory cytokine production. Induction of inflammatory cytokines is mediated via TLR2-dependent activation of NF-κB. Since many of the pathological processes associated with CMV disease are facilitated or directly mediated by inflammatory cytokines, identification of the host membrane detection machinery may ultimately lead to improved therapeutics.
Kinetics of CD4+and CD8+Memory T-Cell Responses during Hepatitis C Virus Rechallenge of Previously Recovered Chimpanzees
Authors: Nascimbeni Michelina , Mizukoshi Eishiro , Bosmann Markus , Major Marian E. , Mihalik Kathleen , Rice Charles M. , Feinstone Stephen M. , Rehermann Barbara
Published: March 2003

The immunological correlates of hepatitis C virus (HCV)-specific immunity are not well understood. Antibodies to HCV structural proteins do not appear to play a key role in clearance of the virus and do not persist after recovery. Here, we studied the kinetics of the cellular immune responses of three HCV-recovered chimpanzees during rechallenge with increasing doses of homologous HCV. Although HCV envelope antibodies remained undetectable throughout the rechallenge, all animals mounted rapid HCV-specific T-cell responses. The pattern of the cellular immune response in blood and liver correlated with the virological outcome. The animal that most rapidly cleared circulating HCV as determined by nested reverse transcription-PCR (RT-PCR) displayed the most vigorous and sustained response of gamma interferon (IFN-γ)-producing and proliferating CD4+T cells in the blood. Vigorous CD4+T-cell proliferation during viremia was followed by an increased frequency and a phenotypic and functional change of the tetramer+CD8+T-cell population. The second animal cleared HCV initially with strong peripheral and intrahepatic CD4+T-cell responses but experienced low-level HCV recrudescence 12 weeks later, when HCV-specific T cells became undetectable. The third animal maintained minute amounts of circulating HCV, detectable only by nested RT-PCR, in the face of a weak IFN-γ+T-cell response. Collectively, the results suggest protective rather than sterilizing immunity after recovery from hepatitis C. The rate of HCV clearance following reexposure depends on the cellular immune response, the quality and quantity of which may vary among chimpanzees that recovered from HCV infection.
Human Immunodeficiency Virus Type 1 Assembly and Lipid Rafts: Pr55

gag

Associates with Membrane Domains That Are Largely Resistant to Brij98 but Sensitive to Triton X-100
Authors: Holm Kirsi , Weclewicz Katarzyna , Hewson Roger , Suomalainen Maarit
Published: March 2003

The assembly and budding of human immunodeficiency virus type 1 (HIV-1) at the plasma membrane are directed by the viral core protein Pr55

gag

. We have analyzed whether Pr55

gag

has intrinsic affinity for sphingolipid- and cholesterol-enriched raft microdomains at the plasma membrane. Pr55

gag

has previously been reported to associate with Triton X-100-resistant rafts, since both intracellular membranes and virus-like Pr55

gag

particles (VLPs) yield buoyant Pr55

gag

complexes upon Triton X-100 extraction at cold temperatures, a phenotype that is usually considered to indicate association of a protein with rafts. However, we show here that the buoyant density of Triton X-100-treated Pr55
gag
complexes cannot be taken as a proof for raft association of Pr55

gag

, since lipid analyses of Triton X-100-treated VLPs demonstrated that the detergent readily solubilizes the bulk of membrane lipids from Pr55

gag

. However, Pr55

gag

might nevertheless be a raft-associated protein, since confocal fluorescence microscopy indicated that coalescence of GM1-positive rafts at the cell surface led to copatching of membrane-bound Pr55

gag

. Furthermore, extraction of intracellular membranes or VLPs with Brij98 yielded buoyant Pr55

gag

complexes of low density. Lipid analyses of Brij98-treated VLPs suggested that a large fraction of the envelope cholesterol and phospholipids was resistant to Brij98. Collectively, these results suggest that Pr55

gag

localizes to membrane microdomains that are largely resistant to Brij98 but sensitive to Triton X-100, and these membrane domains provide the platform for assembly and budding of Pr55

gag

VLPs.
Mutation Patterns and Structural Correlates in Human Immunodeficiency Virus Type 1 Protease following Different Protease Inhibitor Treatments
Authors: Wu Thomas D. , Schiffer Celia A. , Gonzales Matthew J. , Taylor Jonathan , Kantor Rami , Chou Sunwen , Israelski Dennis , Zolopa Andrew R. , Fessel W. Jeffrey , Shafer Robert W.
Published: March 2003

Although many human immunodeficiency virus type 1 (HIV-1)-infected persons are treated with multiple protease inhibitors in combination or in succession, mutation patterns of protease isolates from these persons have not been characterized. We collected and analyzed 2,244 subtype B HIV-1 isolates from 1,919 persons with different protease inhibitor experiences: 1,004 isolates from untreated persons, 637 isolates from persons who received one protease inhibitor, and 603 isolates from persons receiving two or more protease inhibitors. The median number of protease mutations per isolate increased from 4 in untreated persons to 12 in persons who had received four or more protease inhibitors. Mutations at 45 of the 99 amino acid positions in the protease—including 22 not previously associated with drug resistance—were significantly associated with protease inhibitor treatment. Mutations at 17 of the remaining 99 positions were polymorphic but not associated with drug treatment. Pairs and clusters of correlated (covarying) mutations were significantly more likely to occur in treated than in untreated persons: 115 versus 23 pairs and 30 versus 2 clusters, respectively. Of the 115 statistically significant pairs of covarying residues in the treated isolates, 59 were within 8 Å of each other—many more than would be expected by chance. In summary, nearly one-half of HIV-1 protease positions are under selective drug pressure, including many residues not previously associated with drug resistance. Structural factors appear to be responsible for the high frequency of covariation among many of the protease residues. The presence of mutational clusters provides insight into the complex mutational patterns required for HIV-1 protease inhibitor resistance.
Viral Persistence Alters CD8 T-Cell Immunodominance and Tissue Distribution and Results in Distinct Stages of Functional Impairment
Authors: Wherry E. John , Blattman Joseph N. , Murali-Krishna Kaja , van der Most Robbert , Ahmed Rafi
Published: March 2003

Chronic viral infections often result in ineffective CD8 T-cell responses due to functional exhaustion or physical deletion of virus-specific T cells. However, how persisting virus impacts various CD8 T-cell effector functions and influences other aspects of CD8 T-cell dynamics, such as immunodominance and tissue distribution, remains largely unknown. Using different strains of lymphocytic choriomeningitis virus (LCMV), we compared responses to the same CD8 T-cell epitopes during acute or chronic infection. Persistent infection led to a disruption of the normal immunodominance hierarchy of CD8 T-cell responses seen following acute infection and dramatically altered the tissue distribution of LCMV-specific CD8 T cells in lymphoid and nonlymphoid tissues. Most importantly, CD8 T-cell functional impairment occurred in a hierarchical fashion in chronically infected mice. Production of interleukin 2 and the ability to lyse target cells in vitro were the first functions compromised, followed by the ability to make tumor necrosis factor alpha, while gamma interferon production was most resistant to functional exhaustion. Antigen appeared to be the driving force for this loss of function, since a strong correlation existed between the viral load and the level of exhaustion. Further, epitopes presented at higher levels in vivo resulted in physical deletion, while those presented at lower levels induced functional exhaustion. A model is proposed in which antigen levels drive the hierarchical loss of different CD8 T-cell effector functions during chronic infection, leading to distinct stages of functional impairment and eventually to physical deletion of virus-specific T cells. These results have implications for the study of human chronic infections, where similar T-cell deletion and functional dysregulation has been observed.
Validation of a field test for the non-invasive determination of badminton specific aerobic performance
Authors: Wonisch M , Hofmann P , Schwaberger G , von Duvillard S P , Klein W
Published: March 2003

Aim:To develop a badminton specific test to determine on court aerobic and anaerobic performance.

Method:The test was evaluated by using a lactate steady state test. Seventeen male competitive badminton players (mean (SD) age 26 (8) years, weight 74 (10) kg, height 179 (7) cm) performed an incremental field test on the badminton court to assess the heart rate turn point (HRTP) and the individual physical working capacity (PWCi) at 90% of measured maximal heart rate (HRmax). All subjects performed a 20 minute steady state test at a workload just below the PWCi.

Results:Significant correlations (p<0.05) for Pearson’s product moment coefficient were found between the two methods for HR (r= 0.78) and velocity (r= 0.93). The HR at the PWCi(176 (5.5) beats/min) was significantly lower than the HRTP (179 (5.5) beats/min), but no significant difference was found for velocity (1.44 (0.3) m/s, 1.38 (0.4) m/s). The constant exercise test showed steady state conditions for both HR (175 (9) beats/min) and blood lactate concentration (3.1 (1.2) mmol/l).

Conclusion:The data indicate that a valid determination of specific aerobic and anaerobic exercise performance for the sport of badminton is possible without HRTP determination.
Are overground or treadmill runners more likely to sustain tibial stress fracture?
Authors: Milgrom C , Finestone A , Segev S , Olin C , Arndt T , Ekenman I
Published: March 2003

Background:Repetitive high bone strain and/or strain rates, such as those that occur during running, contribute to stress fractures as well as promoting maintenance of or increase in bone mass. Kinematic differences are known to exist between overground and treadmill running and these may be reflected in different bone strains and strain rates during the two running techniques.

Aim:To measure in vivo strains and strain rates in human tibia during treadmill and overground running and determine if there are significant differences in strain and strain rate levels between the two running techniques.

Methods:A strain gauged bone staple was mounted percutaneously along the axial direction in the mid diaphysis of the medial tibia in three subjects, and in vivo tibial strains were measured during treadmill and overground running at 11 km/h.

Results:Axial compression strains (p<0.0001), tension strains (p<0.001), compression strain rates (p<0.0001), and tension strain rates (p<0.0001) were 48–285% higher during overground running than during treadmill running.

Conclusions:On the basis of lower in vivo strains and strain rates, treadmill runners are at lower risk of developing tibial stress fractures, but less likely to achieve tibial bone strengthening, than overground runners.
Tibial shaft fractures in amateur footballers
Authors: Lenehan B , Fleming P , Walsh S , Kaar K
Published: March 2003

Background:Footballers constitute a unique group of patients with tibial shaft fractures. They tend to have excellent general health and well developed musculature in the leg, and their fractures are generally closed injuries caused by low velocity trauma. However, little has been reported on the outcome after tibial shaft fractures in this group.

Objective:To identify patterns of injury, response to treatment, and functional outcome in such a group.

Method:Fifty consecutive tibial shaft fractures in adult footballers treated at Merlin Park Regional Hospital over a five year period were analysed.

Results:Most of the fractures were type A injuries (AO/ASIF classification). The incidence of complications was low. All patients reported good or excellent satisfaction with their outcome. However, only 54% of patients returned to playing competitive football.

Conclusion:Tibial shaft fractures in amateur footballers are associated with good results when traditional outcome criteria are used, but many patients do not regain their previous level of function.
A potential new role for fungi in a wastewater MBR biological nitrogen reduction system
Authors: Guest R K , Smith Daniel W
Published: March 2003

The fastidious nature of nitrifying bacteria has caused many operational problems for wastewater treatment plants employing some form of biological nutrient removal. Research in the field has focused solely on meeting the requirements of this group of bacteria. Recently fungi have been recognized to perform denitrification at greater rates than bacteria. Combining fungi nitrification ability and resistance to inhibitory chemicals, there is the potential for development of a new fungi based biological nitrogen removal system. From the data reviewed, the system would have several significant advantages over conventional biological nutrient removal systems. This paper reviews the ability of fungi to carry out biological nitrogen removal and the potential performance of a fungi based system. Key words: fungi, biological nutrient removal, nitrification, denitrification, membrane bioreactor.
An Integrated Trading Environment: To Improve Market Transparency and Efficiency
Authors: Lau Adela S. M.
Published: March 2003

During the 1997 financial turmoil, the overall boom and slump was mainly due to the collapse of ill-informed speculation and a non-regulated stock market system. This collapse has probably created mistrust among the public and greatly impaired confidence in securities as an investment. From this painful experience, the government should control share prices and prevent extreme fluctuations by improving the transparency and efficiency in trading information transmission, market monitoring and document disclosure.

Therefore, online trading system, cross-market monitoring system and electronic filing system will be recommended in order to improve the low transparency and efficiency of financial information transmission. More importantly, all the information in these systems is inter-related for market monitoring or financial analysis. Thus, an integrated trading environment results in order to reduce redundancy work, error prone and information inefficiency.
E-Procurement in Taiwan: Issues and Viewpoints
Authors: Chong P. Pete , Chen Edward T. , Chen Jason C. H.
Published: March 2003

Much advancement has taken place in E-commerce, especially in the area of e-procurement. This article describes some essential characteristics of e-procurement and its role in e-commerce and industry as a whole. We also discuss some of the newer developments in e-procurement and surmise the necessary modification of these developments for companies in Taiwan.
Online Trading's Impacts on Western Manufacturers' Entry Modes in China
Authors: Li Lee
Published: March 2003

How does online trading affect Western manufacturers' entry modes in China? This inductive study of 20 Western manufacturers and their Chinese intermediaries led to propositions exploring that question. Findings from the study indicate that online trading intensifies the information exchanges between Western manufacturers and their Chinese end users. Such information exchanges provide Western manufacturers with detailed market-specific knowledge. Moreover, online trading intensifies the competition between Western manufacturers as their customers can keep well-informed of their product qualities, new technologies, and prices. Online trading has great positive impacts on Western manufacturers' shift from low-control and low-risk entry modes to high-control and high-risk entry modes.
KNOWLEDGE MANAGEMENT ROUTINES FOR INNOVATION PROJECTS: DEVELOPING A HIERARCHICAL PROCESS MODEL
Authors: TRANFIELD DAVID , YOUNG MALCOLM , PARTINGTON DAVID , BESSANT JOHN , SAPSED JONATHAN
Published: March 2003

In this paper we use the literature on knowledge management and innovation, together with empirical data, to develop a process model for knowledge management routines in the context of innovation projects. First we develop a high-level conceptualisation from the literature, the model characterising knowledge management as consisting of three distinct phases: Discovery, Realisation and Nurture. We then expand this three phase perspective into a model of generic knowledge management routines, reporting four contrasting, exemplar cases from a wide ranging study across business sectors. Using the notions of radical and incremental innovation in both products and processes we illustrate how the three high-level phases may be further expanded into a more detailed conceptualisation of the knowledge management process. This comprises eight generic routines: Search, Capture, Articulate, Contextualise, Apply, Evaluate, Support and Re-innovate. We derive a new description of knowledge management and discuss the practical implications of the model, including the opportunities which exist for cross-sector learning between organisations which are superficially dissimilar. We conclude that the successful management of organisational knowledge in the context of innovation requires attention to be paid to all eight generic routines and to the influence of enablers and blockers operating both inside and outside the framework of routines.
HAVE PROCESS INDUSTRIES SHIFTED THEIR CENTRE OF GRAVITY DURING THE 90s?
Authors: CHRONÉER DIANA
Published: March 2003

Product development is often seen as a main tool for competitiveness in organizations. In process industries, like steel and paper, process and product development are seen as an integrated part. Product development has often been the result of a process development. Heavy investments and costly production give process a priority role in product development. The role of customers and suppliers in development work has increased for process-based companies. This change will have implication on how to organize and manage development in the traditional upstream companies. Therefore, this article presents results that show some of the implications of the changed situation for Swedish process-based companies. The article also emphasizes that there are indications of a shift of traditional upstream companies' centre of gravity due to the changed perspective in development work, towards customer focus.
INDICATORS OF SOCIO-NATURAL CHANGE: SCIENTIFIC MEANING AND CONTEXTUAL INTERPRETATION
Authors: OXLEY T. , LEMON M. , JEFFREY P.
Published: March 2003

This paper addresses the disparity and conflict between scientific meaning and the contextualised interpretation of (predominately) empirical indicators. This disparity arises due to the difficulty that the scientific community experiences when attempting to communicate with the political and planning community whose perspective remains outside the scope of both the indicator and the tools used.

We suggest that for empirical science to be communicated effectively to a policy oriented audience it must be transformed through both theoretical and virtual contexts. The significance of this approach is that at every stage communication becomes possible through a common negotiated reference point, or set of reference points. We highlight a mismatch between the science and the response, emphasising the value of an integrative approach to assessing environmental change and the need for accessible decision support tools in formulating responses to changes in the human-environmental balance.

We propose a framework which directly addresses the perceptual, empirical, theoretical and virtual dimensions of indicators and through which the conflicts between the science and the interpretation of socio-natural change may be overcome.
INVESTIGATION OF DIFFERENT STAKEHOLDER VIEWS OF LOCAL RESIDENT INVOLVEMENT DURING ENVIRONMENTAL IMPACT ASSESSMENTS IN THE UK
Authors: ROBINSON MICHAEL , BOND ALAN
Published: March 2003

Based on the possibility that different stakeholders have different views and aspirations about public involvement in Environmental Impact Assessment (EIA), a study was carried out to test whether this was the case, and whether the urban/suburban public might have different views on involvement of local residents (who are considered to be stakeholders) in EIA to the rural public and whether the views of those with experience of such involvement differ from the views of those without such experience.

A questionnaire survey was carried out of UK EIA consultants and residents of one rural village and one urban area in the UK. The questions were structured in relation to seven issues relating to local residents involvement in EIA: importance; when (at which EIA stage); when (with respect to development sector); when (with respect to impact areas, e.g. air, fauna); to what extent; who; and for what purpose. Chi-squared tests were carried out to identify significant differences between pairs of results.

Significant differences were found between the views of the consultants (who would organise the local residents involvement) and the local residents themselves, for many of the issues investigated. There were also some differences in views between the views of the rural and urban/suburban public for a limited range of issues and some, but not many, differences between the views of those with experience of local residents involvement and those without.

Bearing in mind the limited nature of the survey, the results indicate that there is potential, even where consultants design what they consider to be very good public involvement programmes, for poor acceptance from the local residents and a lack of confidence in the programme. Consultants need to be aware of the range of views of stakeholders in order to develop successful public involvement programmes.
A Shared-Aperture Tracking Display for Augmented Reality
Authors: Chinthammit Winyu , Seibel Eric J. , Furness Thomas A.
Published: March 2003

The operation and performance of a six degree-of-freedom (DOF) shared-aperture tracking system with image overlay is described. This unique tracking technology shares the same aperture or scanned optical beam with the visual display, virtual retinal display (VRD). This display technology provides high brightness in an AR helmet-mounted display, especially in the extreme environment of a military cockpit. The VRD generates an image by optically scanning visible light directly to the viewer's eye. By scanning both visible and infrared light, the head-worn display can be directly coupled to a head-tracking system. As a result, the proposed tracking system requires minimal calibration between the user's viewpoint and the tracker's viewpoint. This paper demonstrates that the proposed shared-aperture tracking system produces high accuracy and computational efficiency. The current proof-of-concept system has a precision of +/− 0.05 and +/− 0.01 deg. in the horizontal and vertical axes, respectively. The static registration error was measured to be 0.08 +/− 0.04 and 0.03 +/− 0.02 deg. for the horizontal and vertical axes, respectively. The dynamic registration error or the system latency was measured to be within 16.67 ms, equivalent to our display refresh rate of 60 Hz. In all testing, the VRD was fixed and the calibrated motion of a robot arm was tracked. By moving the robot arm within a restricted volume, this real-time shared-aperture method of tracking was extended to six-DOF measurements. Future AR applications of our shared-aperture tracking and display system will be highly accurate head tracking when the VRD is helmet mounted and worn within an enclosed space, such as an aircraft cockpit.
Morphology and Nanoindentation Profiles of Automotive Engine Components
Authors: Aktary M. , McDermott M. T. , MacAlpine G.
Published: March 2003

Scanning probe microscopy has been used for the analysis of a wear surface from a component removed from a heavy duty diesel engine. This component is analysed and compared to a wear surface that has been generated in a rig that simulates engine conditions. It was found that the wear surface from the engine component is highly pitted in the regions where contact pressures are exceedingly high, whereas regions further away from the high pressure points are covered with an anti-wear film that resembles the films formed in the wear rig. These results are confirmed by both scanning force microscopy images and nanoindentation results.
Corrosion Resistance of Conversion Film Formed on Aluminium Alloy Using Cerium Salt Surface Treatment
Authors: Zhang W. , Li J.-Q. , Wu Y.-S. , Xu J.-T. , Chen K.
Published: March 2003

Non-chromate conversion films are formed on the surface of an Al-Z n-Mg-Cu alloy using a two step cerium salt treatment. The corrosion resistance of the alloy in chloride solution has been studied after the non-chromate treatment. It was found that the conversion film could greatly improve the corrosion resistance of the alloy to pitting and uniform corrosion in a chloride environment. The non-chromate film can retard both the anodic and cathodic processes. The treated alloy is not sensitive to the changes in the concentration of chloride ions and the pH value of the chloride solution.
Selective Surface Heat Treatment of Cr and CrN Coatings on Steel
Authors: Seok J. W. , Li J. H. , Lin R. Y.
Published: March 2003

Chromium and chromium nitride coatings on steels have been prepared with pulsed dc magnetron sputter deposition at a frequency of 185 kHz and a duty cycle of 96%. The coating process was carried out at 150 W with the substrate temperature maintained at 200°C. For nitride coatings, reactive sputter deposition was carried out in Ar with 3, 5, or 7%N2. Heat treatments were performed for coated steels with an infrared (IR) processing technique in an attempt to modify the interfaces and change coating properties. T he heat treatment was carried out at 400°C for 2 and 5 min. Characterisation of coated samples included X-ray diffraction (XRD), optical microscopy, and microhardness tests to verify the effect of the heat treatment. Results from XRD analysis indicated that IR heat treatment at 400°C for 2 or 5 min did not change the phases present in the coatings. Optical images of the coating microstructure show that cracks were developed on coatings deposited under 7%N2 even after only 2 min heat treatment at 400°C. Severity of cracking is reduced for coatings deposited under low nitrogen contents. No cracks were observed on coatings deposited without nitrogen. Microhardness measurements showed that for all coated specimens, 2 min IR treatment at 400°C gave the highest microhardness. For samples treated for 5 min, the microhardness decreased. X-ray diffraction analysis with slow scanning showed that CrN peaks were developed in the coatings deposited under 7%N2 and heat treated at 400°C for 2 and 5 min.
Mass Transport Driven by Atomic Relocations under High Flux Ion Irradiation at Elevated Temperatures
Authors: Pranevicius L. , Milcius D. , Templier C. , Riviere J.-P. , Pranevicius L. L.
Published: March 2003

Experiments with a nitrogen torch at atmospheric pressure have been performed in order to identify the role of surface processes in the mechanism of nitrogen transport during nitriding of stainless steel AISI 304. The unusually thick (∼175 μm) layers of supersaturated nitrogen solid solution fcc phase were obtained after treatment for 10 min at 450°C. A radically different structure occurs in specimens treated at 550°C. Scanning electron microscopy (SEM) surface and cross-sectional micrographs reveal that the surface topography indicates the degree of modification occurring in the nitrided layer. Surface vacancies generated by surface instabilities move deeply into the bulk at elevated temperatures and form a highly defected layer with pores and microcracks. The transport of nitrogen in austenitic stainless steel is driven by the flux es of matrix atoms directed to stabilise surface instabilities. Nitrogen depth profiles simulated on the basis of the model with the surface atom relocation process and an activation energy of 1·1-1·5 eV, and including balanced flux es of atoms in the bulk for relax ation of surface energy are in quantitative agreement with ex perimental results.
Effect of Heat Treatment on High Pressure Plasma Sprayed Hydroxyapatite Coatings
Authors: Espanol M. , Guipont V. , Khor K. A. , Jeandin M. , Llorca-Isern N.
Published: March 2003

This paper reports the characteristics and properties of two different sets of hydroxyapatite (HA) coatings obtained by thermal spraying two different HA powders, spray dried HA (SDHA) and spheroidisided HA (SHA), at various chamber pressures. The evaluation of the coatings following post-spray treatment at 800°C is also included. Comparisons to the results from the as sprayed coatings were made to show the effects of post-spray heat treatment. The median particle sizes for SDHA and SHA were 35 and 47 μm, respectively. The main difference between the powders is their density and morphology. The SHA powder provides higher density and spherical morphology, and a more porous and rough surface is present in the SDHA powders. These two powders were sprayed using a controlled atmosphere plasma spraying (CAPS) system in the inert plasma spray (IPS) and high pressure plasma spray (HPPS) modes. Four different pressures of 100, 150, 200, and 250 kPa were applied in an argon atmosphere. Post-spray heat treatment was performed to increase the crystallinity of the coatings, to homogenise their structure, and to convert other calcium phosphate phases to HA. Different techniques were used to characterise these coatings. Scanning electron microscopy (SEM) was used to observe surface and cross-section morphology of both powder and sprayed coatings. The phase and chemical characteristics of the samples were evaluated by X-ray diffraction (XRD) and Fourier transform infrared spectrometry (FTIR). Finally, in order to have a qualitative measure of the integrity of the coatings, Vickers hardness testing was performed on polished cross-sections of the coatings.
Fabrication and Characterisation of Laser Surface Modified Plasma Sprayed Alumina Coatings
Authors: Krishnan R. , Dash S. , Sole R. K. , Tyagi A. K. , Raj Baldev
Published: March 2003

Thick alumina coatings fabricated using the air plasma spray (APS) process, predominantly contain metastable γ-Al2O3 phase with a porous microstructure. Presence of such a metastable phase and porosity are detrimental to long term performance of the coating. Such inherent disadvantages can be mitigated to a large extent through the use of a post-spray laser treatment. In the present work, a surface specific CO2 laser heating method was used to achieve this objective. This heating procedure has the ability to transform the γ-Al2O2 phase to the thermodynamically stable α-Al2O3 phase and remove porosities while retaining the metallic substrate intact. Phase analysis by XRD confirmed the transformation. Microstructural analysis by SEM revealed the absence of porosities. Using optimal laser power, an α-Al2O3 coating, ∼150 μm thick, was obtained. The laser treated alumina coating showed an increase in Vickers microhardness from ∼ 1100 to ∼ 2300 HV. Feasibility of making thicker and harder α-Al2O3 coatings by combining the APS process with laser surface modification was demonstrated.
Role of endogenous nitric oxide in airway microvascular leakage induced by inflammatory mediators
Authors: Kageyama N , Miura M , Ichinose M , Tomaki M , Ishikawa J , Ohuchi Y , Endoh N , Shirato K
Published: March 2003

This study examines the role of endogenous nitric oxide (NO) in airway microvascular leakage induced inflammatory mediators, which play an important role in asthmatic airways. Guinea-pigs were anesthetized and mechanically-ventilated with monitoring of arterial blood pressure, and airway microvascular leakage induced by intravenous injection of substance P (SP), leukotriene D4 (LTD4) and histamine was evaluated using Evans blue dye and Monastral blue dye in the presence and absence of the NO synthase inhibitors, L-NG-nitroarginine methyl ester (L-NAME) and L-NG-monomethyl arginine (L-NMMA). The effect of a soluble guanylate cyclase inhibitor, LY83583, on SP-induced dye leakage was also examined. Intravenous injection of SP (1 microgram.kg-1), LTD4 (1 microgram.kg-1) and histamine (100 micrograms.kg-1) significantly increased dye extravasation at all airway levels. Pretreatment with L-NAME (10 mg.kg-1 i.v.) and L-NMMA (100 mg.kg-1 i.v.) significantly inhibited SP-induced extravasation, and L-arginine (100 mg.kg-1 i.v.) reversed L-NAME-induced inhibition. L-NAME (10 mg.kg-1 i.v.) also significantly inhibited LTD4-induced dye extravasation only in central airways, and this inhibitory effect was abolished by a neurokinin-1 (NK1) antagonist, FK888 (10 mg.kg-1 i.v.) pretreatment. Histamine-induced dye extravasation was not affected by L-NAME. LY83583 (2.5 and 7.5 mg.kg-1 i.v.) partially but significantly reduced SP-induced dye leakage. These results suggest that endogenous nitric oxide plays a role in neurokinin-1 receptor-mediated airway microvascular leakage, and presumably involves the guanylate cyclase pathway.