bluuebunny/crossref_metadata_2025 huggingface dataset:
Numerical Models for Composite-Jacketed Reinforced Concrete Bridge Columns
Authors: Haroun Medhat A. , Elsanadedy Hussein M.
Published: August 2003

This paper describes findings from a comprehensive experimental and analytical study on seismic repair and retrofit of model scale bridge columns using advanced composite-material jackets. This study has two phases. In the first phase, fourteen half-scale circular and rectangular reinforced concrete columns were tested for shear and confinement enhancement in a fixed-fixed condition. Three columns were tested in the as-built condition, while ten columns were tested after being retrofitted with different composite-jacket systems. The last column was tested after being repaired with carbon-epoxy composite jacket. In addition to the experimental study, an object-oriented computer program, based on moment-curvature analysis, was written to predict the seismic behavior of all column data. For as-built columns, the program was used to evaluate different shear strength models. However, for repaired and retrofitted column samples, the program was calibrated through a parametric study on two displacement models and six different concrete confinement models. In the second phase of this study, thirteen half-scale circular and square column models with insufficient lap splice length were tested in flexure under lateral cyclic loading. Three column samples were tested in the as-built configuration, whereas ten column samples were tested after being retrofitted with different composite-jacket systems. Another object-oriented computer code was developed for predicting the behavior of the tested columns. The numerical model is based on a moment-curvature analysis of the column section with the inclusion of a bond-slip mechanism. Three different bond-slip models were utilized in the analysis. The developed software was calibrated through a parametric study comparing the experimental and predicted results.
Seismic Performance of Aramid Fiber Square Tubed Concrete Columns with Metallic and/or Non-Metallic Reinforcement
Authors: Yamakawa T. , Zhong P. , Ohama A.
Published: August 2003

In prefabricated Aramid Fiber Reinforced Polymer (AFRP) tubed concrete columns with metallic and/or nonmetallic reinforcement, the AFRP square tube performs the dual functions of stay-in-place formwork and transverse reinforcement. Nine column specimens including a hybrid concrete column with steel bars or AFRP rods for longitudinal reinforcement, were tested under cyclic lateral forces while simultaneously subjected to a constant axial load. Double confinement due to an aramid fiber tube and steel hoops with cross ties can provide a much greater transverse confinement effect. The ply of composite laminates can be designed such that when the shear and the bond strengths exceed the flexural strengths, adequate seismic performance of the hybrid RC columns can be ensured.
Strengthening Prestressed-Concrete Girders with Externally Prestressed PBO Fiber Reinforced Polymer Sheets
Authors: Wu Z. S. , Iwashita K. , Hayashi K. , Higuchi T. , Murakami S. , Koseki Y.
Published: August 2003

This study aims at developing an innovative strengthening system with externally bonded prestressed PBO (short for Polypara-phenylene-Benzo-bis-Oxazole) fiber reinforced polymer (PFRP) sheets, which present equal or higher strength and stiffness in comparison with high strength type of carbon fiber reinforced polymer (CFRP) sheets and great performance in energy absorption superior than other fiber reinforced polymer (FRP) sheets such as aramid and carbon FRP sheets. An experimental program was carried out to confirm the strengthening effects on load-carrying capacity, stiffness characteristics, ductility, and resistance of crack opening of prestressed concrete girders. The main parameters studied are the prestress level, the number of PFRP sheet layers, and resin impregnation of PBO fibers before or after sheet prestressing. An analytical study is also performed in order to investigate the flexural behavior of PC girders strengthened with prestressed PFRP sheets.
Experimental Investigation of Seismic Repair and Retrofit of Bridge Columns by Composite Jackets
Authors: Haroun Medhat A. , Mosallam Ayman S. , Feng Maria Q. , Elsanadedy Hussein M.
Published: August 2003

This paper summarizes the results of comprehensive experimental studies on half-scale bridge columns repaired and retrofitted with composite-material jackets. The experimental program was composed of two interrelated subprograms. Initially, a total of fourteen half-scale squat circular and rectangular reinforced concrete columns were tested under fully reversed cyclic shear in a double bending configuration. In order to provide a basis for comparison, a total of three as-built columns were tested. Another ten column samples were tested after being retrofitted with different composite-jacket systems. One circular as-built column was repaired after failure. The repair process involved both crack injection, as well as addition of carbon/epoxy composite jacket. The repaired column was then retested and evaluated. Experimental results showed that all as-built columns developed an unstable behavior and failed in brittle shear mode. The common failure mode for all retrofitted samples was due to flexure with significant improvement in the column ductility. The repaired column demonstrated ductility enhancement over the as-built sample. In the second subprogram, a total of thirteen half-scale circular and square column models were constructed with short lap-splice details at the base, and were tested in flexure under lateral cyclic loading. Three as-built columns were tested and a total of ten columns were tested after being retrofitted with different composite-jacket systems. In general, the common mode of failure for the as-built samples was a brittle failure due to bond deterioration of the lap-spliced longitudinal reinforcement. The jacketed circular columns demonstrated a significant improvement in their cyclic performance. However, tests conducted on square jacketed columns showed a very limited improvement in clamping on the lap splice region and for enhancing the ductility of the column.
Capacity Assessment of RC Subassemblages Upgraded with CFRP
Authors: Prota A. , Nanni A. , Manfredi G. , Cosenza E.
Published: August 2003

Many gravity load designed (GLD) reinforced concrete (RC) structures located in seismic areas are in need of upgrade. As an alternative to traditional upgrade solutions, an innovative technique based on the use of Fiber Reinforced Polymer (FRP) composites was proposed and experimentally validated. The technique consists of strengthening reinforced concrete connections by means of the combined use of FRP laminates and FRP near surface mounted (NSM) bars. In parallel, a theoretical approach for the assessment of the connection capacity was developed based on the analysis of each component (i.e., column, beam and joint), in order to determine which component controls failure. The outcomes of the analysis were compared to the experimental results with considerations on the reliability of the approach and aspects slated for future investigations. The behavior of the FRP-confined column cross section was also analyzed and it is herein discussed based on recorded strains in internal steel bars and FRP jacket.
Section Properties and Buckling Behavior of Pultruded FRP Profiles
Authors: Roberts T. M. , Masri H. M. K. J. A. H.
Published: August 2003

Experimental determination of the flexural and torsional properties of pultruded FRP profiles, based on full section and coupon tests, is described. Results for a range of I-profiles indicates that transverse shear moduli, determined from full section three point bending tests, are influenced significantly by localised deformation at the supports. Closed form solutions for the influence of shear deformation on global flexural, torsional and lateral buckling of pultruded FRP profiles have been developed. Parametric studies for a range of I-profiles indicate that shear deformation can reduce flexural and torsional buckling loads by up to 10%. For wide flange I-profiles pre-buckling displacements can increase lateral buckling moments by more than 20% while the influence of shear deformation is relatively minor.
Effects of Microstructures of Smart Fiber Composites on Embedded Fiber Bragg Grating Sensors
Authors: Zhang A-Ping , Tao Xiao-Ming , Tam Hwa-Yaw
Published: August 2003

This paper presents the results of an investigation on the effects of composite microstructures on the spectral response of fiber Bragg grating (FBG) sensor embedded in smart carbon-epoxy fiber composite, based on the mechanical finite element analysis and optical coupled mode theory. The FBG sensors are embedded in the directions parallel or intersected to the axis of reinforcing carbon tows. It shows that FBG sensors have good linear spectral responses for axial loads in both cases of sensor arrangements, and their sensitivities are close to each other. For lateral compression loads, however, the parallel arrangement has much smaller effects on the spectra than that of intersected arrangement, and thus is proposed for the sensing applications.
Young's Modulus of Coated Inclusion Composites by the Generalized Mechanics-of-Materials (GMM) Approach
Authors: LIM Teik Cheng
Published: August 2003

A micromechanical model of the Young's modulus for three special cases of composites - continuous unidirectional fiber composites, particulate composites and periodically bilaminate composites - has been developed within the framework of the mechanic-of-materials approach. Parallel-series (PS) and series-parallel (SP) schemes were adopted based upon opposing combination sequence of the parallel model (direct rule-of-mixture) and the series model (inverse rule-of-mixture). By expressing the inclusion's geometrical characteristics in terms of reinforcement volume fraction and interphase volume, a set of reinforcement parameters for the inclusion and its interphase are extracted. Based on reinforcement parameters for the special cases, those of more general cases, which are intermediates of the special cases, are obtained by curve-fitting approximation. Young's modulus of simple cases such as coated fiber composites in longitudinal direction and coated lamina composites are shown to be approximate to the parallel and series models respectively. Cases such as coated fiber composites in transverse direction and coated particulate composites are compared with other results and observed to be highly and moderately conservative by the PS and SP techniques respectively.
Influences of Tensile Rates and Filler Content on Mechanical Properties for PP-GB Composites
Authors: Liang Ji-Zhao
Published: August 2003

Tensile properties are important use performances of materials. In the present paper, the tensile properties, such as elastic modulus (Ec)and yield strength of glass bead-filled polypropylene (PP)composites were measured by using an Instron material tester at room temperature and varied tensile rates, to identify the effects of tensile rates and filler concentration on these tensile properties. The fillers were A-glass beads, and the surface was pretreated with silane coupling agent. The fillers and PP with different proportion were compounded in a twin-screw extruder in temperature range of 160-230 C to produce the composites. The results showed that the Ec increased nonlinearly with increasing the filler content at lower tensile rates, while it did not vary practically with the filler concentration at the highest tensile rate. When the filler content was a constant, Ec was approximately an exponential function of tensile strain rates, except for individual data points. The tensile yield stress (σyc)decreased nonlinearly with the addition of the filler volume fraction (ϕf at lower tensile rates, while it decreased almost linearly with the increase of ϕf at highest tensile rate. Similarly, σyc increased with increasing tensile strain rates as a form of index function. Furthermore, for these composites the relationship among Ec, σyc, tensile strain rates and ϕf were discussed.
Effect of Flax/PP Panel Process Parameters on Resulting Composite Properties
Authors: van de Velde Kathleen , Kiekens Paul
Published: August 2003

When producing (pressing) flax/PP composite panels, several processing parameters have to be considered. This paper describes how these parameters affect some properties of the resulting panel. The multidirectional flax/PP composite panels were made from needle-punched hybrid nonwovens. First the most appropriate process times and temperatures were determined, using unmodified flax/PP nonwovens. Once these parameters were optimized, also panels consisting of modified flax/PP (boiled and bleached flax) were pressed. Degree of needling and test direction were other parameters that were considered. Density, thickness, relative surface weight and flexural properties were determined. Extra needling only seemed useful at low process temperatures while test direction had no clear effect on results. Flax treatments did not lead to the expected property improvements but it is believed that combining a mild flax treatment with modified PP might lead to improved results, and possibly to a reduction in the odor that is released during and after production.
Consolidation of Thermoplastic Composites
Authors: Bersee H. E. N. , Beukers A.
Published: August 2003

The consolidation of CETEX® glass-PEI prepreg has been investigated at a micro level, which is the flattening of the prepreg layers and the inherent establishing of intimate contact between two adjacent layers. The consolidation phenomena were investigated by C-scanning of 2-layer laminates, in which the standard deviation was taken as an indication of the presence of voids within the laminate and of the homogeneity in laminate thickness. The decrease in standard deviation with pressure and temperature is for a large extent caused by straightening of the fabric. A further increase in pressure and temperature, therefore, does not result in a large decrease of standard deviation. The increase of the standard deviation above the critical temperature is most likely to be caused by matrix flow.
Fiber Reorientation in Laminated and Woven Composites for Finite Element Simulations
Authors: Tabiei Ala , Ivanov Ivelin
Published: August 2003

A simple technique for fiber reorientation in laminated and woven composite material is presented in this paper. This technique is suitable for nonlinear finite element simulations of composite structure failure. The developed technique is implemented in the nonlinear explicit finite element code DYNA3D to demonstrate the effect of the fiber reorientation on the behavior of laminated composite materials in crash simulations. The same technique is added to a woven fabric composite material micromechanical model to account for the change of the model geometry. Using an incremental approach programmed in the MATLAB software, the stiffness change of the woven composite micromechanical model as a function of the yarn tow reorientation is investigated. Significant change in the elastic properties is observed as a result of the scissoring effect and fiber reorientation in woven fabric composites.
Defining and Classifying Supervisory Neglect
Authors: Coohey Carol
Published: August 2003

The purpose of this study is to develop and test a classification system for different types of supervision problems. Several prominent child maltreatment typologies were reviewed to determine the level of definitional agreement between systems; identify strengths and weaknesses within systems; and derive a consensual definition of child neglect, its major subcategories (physical, supervisory, and emotional), and 10 types of supervisory neglect. Six hundred two substantiated child abuse and neglect reports were used to test the system’s interrater reliability. The interrater reliability was excellent for most types of problems. Not watching a child closely enough (29.8% of the reports) made up the largest single type of supervisory neglect, followed by leaving a child alone without a caretaker (24.5%) and leaving a child with an unsuitable caretaker (19.7%). The article concludes with a discussion on how and in what context the system can be used.
The Effect of Childhood Maltreatment on Adult Criminality: A Tobit Regression Analysis
Authors: Grogan-Kaylor Andrew , Otis Melanie D.
Published: August 2003

This article reports on the results of an analysis of a data set containing information on 667 nonmaltreated and 908 maltreated children. The data also contain information on whether the study subjects were arrested in early adulthood. Because adult arrests are an imperfect and censored measure of antisocial behavior, tobit regression analysis was used to examine the effect of the subjects’ experiences of child maltreatment on later arrests while controlling for those subjects’ demographic characteristics. The analysis finds that children’s age, race, and sex and experiences of child neglect all have an impact on subsequent adult arrests. However, physical abuse and sexual abuse do not emerge as statistically significant predictors of arrests in this model. The study also illustrates a method for the decomposition of tobit coefficients to extract more information from them.
Medical, Legal, and Mental Health Service Utilization by Physically Abused Children and Their Caregivers
Authors: Swenson Cynthia Cupit , Brown Elissa J. , Sheidow Ashli J.
Published: August 2003

The use of medical, legal, and mental health services was examined among 37 Medicaid-eligible, physically abused children and their caregivers. Fewer than half of the children received a medical examination related to the physical abuse, but the majority had received basic wellness care, including immunizations. Roughly half of the cases were heard in family court. Fewer than half of the children were receiving mental health services. Children were more likely to receive services if the maltreating caregiver was not in the home. More maltreating caregivers received mental health services than did their children, but this still only accounted for half of the parents. Caregivers were more likely to receive treatment if they acknowledged the abuse. Children who participated in treatment showed reductions in parent-reported problem behaviors but showed increases in anxiety in comparison to children who did not participate in treatment.
Decomposing Black-White Differences in Child Maltreatment
Authors: Ards Sheila D. , Myers Samuel L. , Chung Chanjin , Malkis Allan , Hagerty Brian
Published: August 2003

This article examines conflicting visions of the racial composition of the maltreated populations. The National Child Abuse and Neglect Data System (NCANDS) data shows Blacks are overrepresented among reported and substantiated abuse and neglect cases, while the National Incidence Study of Child Abuse and Neglect (NIS) shows no apparent overrepresentation of children of color. To understand the conflicting evidence, the authors produce from NIS approximate measures of maltreatment rates in NCANDS. Maltreatment rates is broken down into allegation, report and substantiation components. Without disaggregating the data by welfare status, all or most of the racial gap in official maltreatment is found to arise from racial differences in allegations. Disaggregation changes the results. Among welfare cases, on average, half of the Black-White gap in maltreatment is due to racial differences in substantiation. Among nonwelfare cases, about half of the racial gap in official maltreatment is due to racial differences in allegations.
A Multilevel Study of Neighborhoods and Parent-to-Child Physical Aggression: Results From the Project on Human Development in Chicago Neighborhoods
Authors: Molnar Beth E. , Buka Stephen L. , Brennan Robert T. , Holton John K. , Earls Felton
Published: August 2003

The majority of children in the United States experience parent-to-child physical aggression (PCPA), a disciplinary strategy out of favor with many experts. Several decades of research have documented a link between community characteristics and severe child maltreatment. None have taken a multilevel approach to study whether neighborhoods affect the amount of corporal punishment and/or physical abuse used by individual families. Data for this article come from the Project on Human Development in Chicago Neighborhoods and were analyzed using hierarchical linear modeling. An interval scale of PCPA was developed. Values obtained show that several neighborhood characteristics were associated with PCPA. Immigrant concentration remained significant after controlling for family composition. A cross-level interaction was found between neighborhood social networks and Hispanic race/ethnicity. The article’s conclusion is that neighborhood characteristics may influence the amount of PCPA used by families. Neighborhood intervention strategies hold promise.
Improving the Measurement of Child Neglect for Survey Research: Issues and Recommendations
Authors: Slack Kristen Shook , Holl Jane , Altenbernd Lisa , McDaniel Marla , Stevens Amy Bush
Published: August 2003

There is a great need for developing and validating measures of child neglect that can be applied to survey samples outside of a child welfare context. A prospective assessment of child neglect would afford a better estimation of the etiology of various types of child neglect and would greatly inform the development of primary prevention strategies related to child maltreatment. This article offers guidance on the tasks involved with constructing new measures of neglect for prospective survey research. Methodological issues pertaining to child neglect measurement are discussed, and a framework is offered for developing neglect measures for survey research. A discussion is also offered on how this framework is being applied in an ongoing longitudinal study of low-income families with young children. The intended result of this exercise is to encourage the development of new child neglect measures for survey research with both high-risk and general populations.
Adolescent Pregnancy and Homicide: Findings From the Maryland Office of the Chief Medical Examiner, 1994-1998
Authors: Krulewitch Cara J. , Roberts Darryl W. , Thompson Linda S.
Published: August 2003

Homicide has remained the third leading cause of death among girls aged 10 to 19 for more than a decade. Recent research indicates that pregnant or postpartum teens are three times more likely to be victims of homicide compared to their nonpregnant counterparts. These findings portray a compelling picture that leads the authors to investigate the relationship between homicide and pregnancy among teens in Maryland. The purpose of this study is to compare women whose deaths had been evaluated by the medical examiner and who had evidence of pregnancy to women without evidence of pregnancy, with a particular focus on adolescents; 329 (17.7%) adults and 66 (32.7%) adolescents were victims of homicide. Adolescent homicide victims were 3.7 (1.2 to 11.8) times more likely to be pregnant compared to adult homicide victims. The rate of homicide was nearly double in all women who were pregnant. Further research is necessary to evaluate factors associated with these risks so that the future generation and society are protected.
Public Health and Child Maltreatment Prevention: The Role of the Centers for Disease Control and Prevention
Authors: Hammond W. Rodney
Published: August 2003

Child maltreatment is a serious and preventable public health problem. Recent studies indicate a dose-response relationship between exposure to child maltreatment and the presence of adult diseases, clearly positioning child maltreatment as a public health burden. This commentary describes the Center for Disease Control and Prevention’s (CDC) public health approach to prevention, and identifies elements of the CDC role that are complementary to the efforts of criminal justice and child protective services. CDC’s goal for child maltreatment prevention is to assure the widespread adoption of prevention and intervention strategies that are evidence based. Immediate and practical impact can occur by improving collection of child maltreatment data, emphasizing positive parenting skills, and promoting programs representing the best prevention practices in child maltreatment prevention.
A Proposal for Developing a Critical Pedagogy in Management from Researching Organizational Members' Everyday Practice
Authors: Samra-Fredericks Dalvir
Published: August 2003

This article outlines a proposal for developing a critical pedagogy in management which also overcomes four specific problems associated with critical approaches. They are: superior moralizing; abstraction/irrelevance; difficulties in surfacing and questioning the `taken-for-granted' that pervades management practice; and availability of appropriate curriculum content for doing so. It is suggested that the crucial first step is to undertake research in a way that preserves the complex interpersonal weaving of the taken-for-granted social/moral, political and economic threads of organizational members' lived experiences. This necessitates undertaking organizational ethnographies which are extended here to include audio recordings of the naturally occurring talk-based interactive routines of managers over a period of time. The subsequent generation of empirical materials in the form of detailed transcribed interactive routines, when allied with the interpretive resource of `validity claims' drawn from Habermas's critical theory of communicative action, allows for a fine-grained analysis of the everyday taken-for-granted construction of social order. One short extract is reproduced to illustrate the level and scope of analysis and the possibilities for critical reflection.
Developing the Global Manager Using a Capability Framework
Authors: Townsend Peter , Cairns Len
Published: August 2003

A significant educational challenge for the future of international management in western nations is satisfying multicultural domestic markets, and overseas visitors, who have profoundly different cultural beliefs and traditions from those of the traditional western populations. With the emerging growth of one global market, limited vigorous research exists concerning the management of these globally diverse perspectives. The present theories and models have arisen, predominantly, from western paradigms and are largely based on rational scientific approaches to analysis, which are not directly relevant to the different perspectives necessary for multicultural management. The breadth and depth of global knowledge and competencies required is beyond any one individual or method of education and hence a new management development framework is required to deal with what are often familiar problems occurring in unfamiliar cultures/contexts. This article reviews the challenges for education to address such new needs, not always previously included in management curricula—including the competencies required for servicing multicultural markets, and provides a proposed `capability' model appropriate for developing managers in the global context to move beyond basic competence to enhanced flexibility and adaptability. The authors suggest that in order to develop `globally capable managers', experiential engagement beyond competency-developing so-journer or tourist activity by serious management students is necessary. The suggested student international exchange models with direct overt cultural engagement elements in the curriculum are offered as one answer.
Dyslogistic Information Ecologies
Authors: Letiche Hugo , van Mens Lucie
Published: August 2003

This article explores the dyslogistics (spoken badly/pertaining to dysfunctioning communication) of organizational interaction. Dyslogistics are to be opposed to eulogistics ( dys + (eu)logistic). The term is attributed to Jeremy Bentham ( Webster's Dictionary , 1913 edn). Two ethnographic cases within a single business organization are presented to explore what Nardi and O'Day call an information ecology . But while their information ecologies seem self-evidently to lead to organizational learning, ours will point to complex and often equivocal interactions, sometimes even to oppressiveness .
Forbidden Knowledge
Authors: Czarniawska Barbara
Published: August 2003

There is a body of organizational knowledge that offers insight and reflection over the practices of organizing. Yet most of the curricula steer clear of it, insisting on propagating modernist ideas of control and masculine ideas of mastery. Is it because the new ideals are not yet in place or because reflection over practice is not seen as worth propagating? What kind of organization theory is needed at present and by whom? Are students, managers, and organization researchers interested in the same kind of topics? Rather than providing answers, the essay aims at opening a debate.
Coating of Polypropylene Nonwovens with Acrylic Copolymers
Authors: Mondal S. , Gupta B. , Singh H.
Published: August 2003

Spun bonded polypropylene (PP) has several advantages, such as low density, chemical resistance, mildew and stain resistance, good dimensional stability, and low cost. However, it has some disadvantages, also. It is porous, UV stability is poor and it is difficult to dye or print. Coating of PP nonwoven with acrylic copolymer improves tensile strength, abrasion resistance, and UV stability. Tear strength of the coated nonwovens decrease, due to immobility of filaments during the tearing process. SEM shows that porosity decreases and pigment particles are entrapped by copolymer films after coating.
New Development of Cellular Textile Composites for Energy-Absorption Applications
Authors: Tao X. M. , Xue P. , Yu T. X.
Published: August 2003

The design and fabrication of a new class of knitted textile composites, cellular textile composites, are described in this paper, based on our extensive studies on the large deformation mechanisms and energy-absorption behavior of these kinds of materials. The material system and the reinforced fabric architecture are specially selected so as to make the cellular textile composite have better mechanical properties than its components, fiber or matrix. The cell configuration and cell pattern are designed and optimized to achieve higher energy-absorption capacity. The effects of geometric parameters, such as cell height, diameter ratio of cell-top to cell-bottom, semiapical angle of the flat-topped conical shell, cell wall area and cell density are experimentally and analytically studied, leading to an optimal design of the cell geometry and cell distribution.
Effect of Bonding Resins on the Flammability Properties and Thermal Behaviour of Cotton and Cotton/PESFR Woven Fabrics
Authors: Lefebvre J. , Le Bras M. , Lefort B. , Drevelle C. , Duquesne S. , Vouters M. , Magniez C.
Published: August 2003

This study deals with the influence of two binder resins (acrylic and styrene-butadiene resins) on the fire properties and the thermal behaviour of cotton and cotton/flame retardant polyester (PESFR) textiles. Lab-scale fire testings (limiting oxygen index and vertical fire test) have shown that the impregnation of the cotton/polyester fabrics leads to a dramatic loss of fire performance. Therefore, a thermogravimetric study (under oxidative and inert atmospheres) of cotton/polyester blends, impregnated or not impregnated, were carried out to understand the interactions between the fabrics and resins. Data of these thermogravimetric analyses (TGA) were then modelled using Invariant Kinetic Parameters methods to determine the kinetics parameters and the modes of degradation of the impregnated fabrics.
Ham-Wasserman Lecture: Role of the Plasminogen System in Fibrin-Homeostasis and Tissue Remodeling
Authors: Collen Désiré
Published: August 2003

Plasminogen can be converted to plasmin either via the tissue-type plasminogen activator (t-PA) or via the urokinase-type plasminogen activator (u-PA)/u-PA receptor (u-PAR) pathway. A dual role for these pathways is now well established: 1) t-PA is involved in fibrin homeostasis and 2) u-PA is primarily involved in cell migration and tissue remodeling. t-PA mediated activation is used for thrombolytic therapy of acute myocardial infarction and some other thromboembolic diseases. The u-PA mediated pathway, in concert with the matrix metalloproteinase (MMP) system, plays a pleiotropic role in arterial neointima formation, atherosclerosis, angiogenesis, tumor growth metastasis, and infarction. However, therapeutic interventions in the u-PA/MMP system remain to be further defined.
Erythropoietin: A Paradigm for the Development of Practice Guidelines
Authors: Rizzo J. Douglas , Seidenfeld Jerome , Piper Margaret , Aronson Naomi , Lichtin Alan , Littlewood Timothy J.
Published: August 2003

Erythropoietin (EPO) is an endogenous hormone produced in the kidney that regulates red blood cell production within the body. Since the cloning and first clinical introduction of recombinant erythropoietin (epoetin) in the late 1980s indications and usage of epoetin have expanded significantly. It is estimated that as many as one third of patients with substantial anemia (hemoglobin less than 10.0 g/dL) resulting from chemotherapy for cancer are treated with epoetin. Though use of epoetin may avoid the inconvenience and infectious risk of blood transfusions, it is expensive and its benefit in some clinical scenarios has been modest. Like many new technologies, strong evidence suggesting situations where the benefit is high has lagged behind its adoption by patients and practitioners. As well, epoetin is expensive and third party payers do not always reimburse it. Research suggests there is considerable variation in epoetin usage in practice.

To provide guidance to hematology/oncology specialists regarding use of epoetin, the American Society of Hematology (ASH) and the American Society of Clinical Oncology (ASCO) proposed that the Agency for Healthcare Research and Quality (AHRQ) fund an evidence review by one of the Evidence-based Practice Centers (EPC) that would be used to develop evidence-based guidelines for members of the society. This review highlights principles of evidence-based medicine, distills and appraises the evidence in the published literature that supports the use of epoetin, and presents evidence-based recommendations for use of epoetin in situations where benefit is substantiated by high-quality studies. As well, this review addresses some of the difficulties of performing clinical research in this area, provocative research findings that will require further study, and suggestions regarding epoetin in those areas where further strong evidence has yet to be developed.
Chronic Lymphocytic Leukemia: Case-Based Session
Authors: Rai Kanti R. , Döhner Hartmut , Keating Michael J. , Montserrat Emili
Published: August 2003

Drs. Hartmut Döhner, Michael J. Keating, Kanti R. Rai and Emili Montserrat form the panel to review chronic lymphocytic leukemia (CLL) while focusing on the clinical features of a particular patient. The pace of progress in CLL has accelerated in the past decade. The pathophysiological nature of this disease, as had been known in the past, was based largely on the intuitive and empiric notions of two leaders in hematology, William Dameshek and David Galton. Now the works of a new generation of leaders are providing us with the scientific explanations of why CLL is a heterogeneous disease, perhaps consisting of at least two separate entities. In one form of CLL, the leukemic lymphocytes have a surface immunoglobulin (Ig) variable region gene that has undergone somatic mutations, with tell-tale markers suggesting that these cells had previously traversed the germinal centers. Such patients have a distinctly superior prognosis than their counterparts whose leukemic lymphocytes IgV genes have no mutations (these are indeed immunologically naive cells), who have a worse prognosis. The introduction of fluorescence in situ hybridization (FISH) technique has provided us with new insights into the diverse chromosomal abnormalities that can occur in CLL, and which have significant impact on the clinical behavior and prognosis of patients with this disease.

Major advances in therapeutics of CLL also have occurred during the past decade. Two monoclonal antibodies, Campath-1H (anti-CD52) and rituximab (anti-CD20), and one nucleoside analogue, fludarabine, have emerged as three agents of most promise in the front-line treatment of this disease. Studies currently in progress reflect our attempts to find the most effective manner of combining these agents to improve the overall survival statistics for CLL patients. As in many other hematological malignancies, high dose chemotherapy followed by autologous or HLA-compatible allogeneic stem cells rescue strategies are under study as a salvage treatment for a relatively younger age group of CLL patients with poor prognosis characteristics.
Multiple Myeloma
Authors: Dalton William S. , Bergsagel P. Leif , Kuehl W. Michael , Anderson Kenneth C. , Harousseau J. L.
Published: August 2003

Multiple myeloma (MM) is a malignancy of the plasma cell characterized by migration and localization to the bone marrow where cells then disseminate and facilitate the formation of bone lesions. Unfortunately, while treatment of this disease is effective in palliating the disease, and even prolonging survival, this disease is generally regarded as incurable. Understanding the basic biology of myeloma cells will ultimately lead to more effective treatments by developing target based therapy.

In Section I, Dr. Bergsagel discusses the molecular pathogenesis of MM and shares insights regarding specific chromosomal translocations and their role in the genesis and progression of MM. New information regarding FGFR3 as an oncogene as well as how activating mutations may contribute to disease evolution and may be an important target for novel therapeutics of MM is presented.

In Section II, Dr. Anderson elaborates on novel therapeutic approaches to MM also targeting fundamental genetic abnormalities in MM cells. Both preclinical and clinical studies of novel agents including PS-341 and IMiDs are highlighted.

In Section III, Dr. Harousseau discusses the role of autologous stem cell transplant in MM. He highlights clinical trials addressing the question of conditioning regimens and the impact of tandem transplants. He also addresses the role of allogeneic BMT and the use of attenuated dose conditioning regimens (so called mini-allogeneic transplants) in the treatment of MM.

In Section IV, Dr. Dalton provides an overview of the current state of myeloma therapy and summarizes the different and exciting approaches being undertaken to cure this disease.
Hodgkin's Lymphoma: Basing the Treatment on the Evidence
Authors: Connors Joseph M. , Noordijk Evert M. , Horning Sandra J.
Published: August 2003

This paper examines the evidence available to guide treatment decisions in three areas of Hodgkin's lymphoma management. In Section I Dr. Evert Noordijk describes evolving strategies for patients with early stage disease outlining the eras during which the focus has changed from initially accomplishing cure through refining and intensifying the treatment to one of maximizing cure rates and finally into a patient-oriented era in which the twin goals of maintaining high rates of cure and minimizing late toxicity are being achieved. In Section II Dr. Sandra Horning reviews the way in which the cooperative groups of North America and Europe have built upon initial observations from single centers to assemble the trials that have defined the treatment for advanced stage Hodgkin's lymphoma. Over a period of almost three decades, these well-constructed trials have defined a current standard of treatment, ABVD chemotherapy and are now investigating innovative approaches to move beyond this standard. She also indicates the need to appreciate diagnostic factors and the implications of prognostic factor models for the design and interpretation of clinical trials. In Section III Dr. Joseph Connors summarizes the evidence available to inform our choice of treatment for the uncommon but important entity of lymphocyte predominance Hodgkin's lymphoma. Once again, the guidance that can be derived from carefully conducted clinical investigation is used to address the issues surrounding choice of treatment, reasonable monitoring in long term follow-up and the clear-cut need to base diagnosis on objective immunohistochemical evidence.
New Approaches to Lymphoma Diagnosis
Authors: Harris Nancy Lee , Stein Harald , Coupland Sarah E. , Hummel Michael , Favera Riccardo Dalla , Pasqualucci Laura , Chan Wing C.
Published: August 2003

Recent years have brought an explosion of new diagnostic tools to the pathology of lymphomas, which have permitted more precise disease definition and recognition of factors that can predict prognosis and response to treatment. These new methods exploit both the biological features of normal lymphocytes as they progress through differentiation pathways and the genetic abnormalities that characterize malignant transformation. These features can be assessed in individual tumors with techniques that detect proteins (immunophenotyping), messenger RNA (in-situ hybridization), or changes in DNA [Southern blot, PCR, fluorescence in-situ hybridization (FISH), and gene sequencing]. Recently, the novel technology of “gene chips” or DNA microarrays has greatly enhanced the efficiency of analyzing expression of many genes simultaneously at the RNA level. Understanding the relationship of lymphoid neoplasms to their normal counterparts and the genetic events that lead to malignant transformation in lymphoid cells are essential for physicians caring for patients with lymphoma, since these are the basis of modern classification, diagnosis, and prognosis prediction. Although microarray technology is not ready for prime time in the daily diagnosis of lymphoma, practitioners should understand its potential and limitations.

The vast majority of lymphoid neoplasms worldwide are derived from B lymphocytes at various stages of differentiation. The review by Harald Stein and colleagues present the events of normal B-cell differentiation that are relevant to understanding the biology of B-cell neoplasia. These include antigen receptor [immunoglobulin (Ig)] gene rearrangement, somatic mutations of the Ig variable region genes, receptor editing, Ig heavy chain class switch, and differential expression of a variety of adhesion molecules and receptor proteins as the cell progresses from a precursor B cell to a mature plasma cell. Most lymphoid neoplasms have genetic abnormalities, many of which appear to occur during the gene rearrangements and mutations that characterize normal B-cell differentiation. Dr. Riccardo Dalla Favera reviews the mechanisms of these translocations and other abnormalities, and their consequences for lymphocyte biology. The association of specific abnormalities with individual lymphomas is reviewed. Dr. Wing C. Chan reviews the technology and applications of DNA microarray analysis, its promises and pitfalls, and what it has already told us about the biology of lymphomas. Finally, what does this all mean? The applications, both current and future, of these discoveries to the diagnosis and treatment of patients with lymphoma are discussed by Dr. Nancy Lee Harris.
Immunotherapy of Non-Hodgkin's Lymphomas
Authors: Press Oliver W. , Leonard John P. , Coiffier Bertrand , Levy Ronald , Timmerman John
Published: August 2003

Recent years have witnessed the development of a variety of promising immunotherapies for treating patients with non-Hodgkin's lymphomas. Foremost among these advances is the exciting success of monoclonal antibodies directed against lymphocyte surface antigens. Rituximab is a chimeric (human-mouse) anti-CD20 antibody that induces responses in approximately half of the patients with relapsed indolent lymphomas and a third of patients with relapsed aggressive lymphomas when used as a single agent. Response rates appear even higher (up to 70%) for newly diagnosed patients treated with Rituximab monotherapy. Other promising antibodies for treatment of B cell malignancies include epratuzumab (anti-CD22), CAMPATH-1H (anti-CD52w), and Hu1D10 (anti-class II HLA). Even more exciting than antibody monotherapy is the prospect of combination antibody therapy (e.g. rituximab + epratuzumab) or combination chemotherapy and antibody therapy. In this regard, a recent phase III randomized trial from the GELA group in France demonstrated statistically significantly superior complete and overall response rates and superior event-free and overall survivals for elderly patients with newly diagnosed diffuse aggressive B cell lymphomas treated with CHOP + rituximab compared with CHOP alone. Confirmatory cooperative group trials combining chemotherapy with antibody therapies are currently underway. Another approach to augment the efficacy of antibodies is to deploy them in radiolabeled form. Iodine-131, Yttrium-90, and Copper-67 labeled monoclonal antibodies targeting CD-20, CD-22, HLA class II, and other cell surface antigens have been tested and demonstrate higher overall response rates (50-80%) and complete response rates (20-40%) than unlabeled antibodies. Pilot studies combining radiolabeled antibodies with either standard dose chemotherapy or myeloablative chemoradiotherapy with stem cell transplantation also appear very promising. Lymphoma vaccines have also produced very encouraging results in single institution studies at Stanford and the National Cancer Institute, with responding patients demonstrating superior event-free and overall survival than historical controls. Phase III randomized trials of idiotype vaccines are currently underway and novel new vaccine approaches are also being tested.
MALT Lymphomas
Authors: Cavalli Franco , Isaacson Peter G. , Gascoyne Randy D. , Zucca Emanuele
Published: August 2003

This review addresses the biology and the treatment of lymphomas arising from mucosa-associated lymphoid tissue (MALT). This entity, first described in 1983, represents about 8% of all non-Hodgkin's lymphomas and was recently re-classified as “extranodal marginal zone lymphomas of MALT-type.” The term marginal zone lymphoma (MZL) encompasses the three closely related lymphoma subtypes of nodal, primary splenic and extranodal lymphomas of MALT type: the latter represent the vast majority of MZL. These lymphomas arise at different anatomic sites, are composed of mature B-cells lacking expression of CD5 and CD10, often present with overlapping morphologic features, but typically quite distinct clinical behaviors. Only very recently cytogenetic/molecular genetic observations have underlined the distinctiveness of these three lymphoid neoplasms, which in both the R.E.A.L. and WHO-classifications are included in the general term of MZL. MALT lymphomas arise in numerous extranodal sites, but gastric MALT lymphoma is the most common and best studied and is, therefore, the paradigm for the group as a whole.

Dr. Isaacson describes the principal histological features of these lymphomas, including criteria to distinguish this entity from other small B-cell lymphomas. Several lines of evidence suggest that gastric lymphoma arises from MALT acquired as the result of aH. pyloriinfection. However, at least 1/3 of cases do not respond to eradication ofH. pylori. Very recent data suggest that both t(11;18) (q21;q21) and bcl10 nuclear expression are associated with failure to respond to this treatment.

Dr. Gascoyne discusses the biologic function of proteins deregulated through the different translocations, which play a role in pathogenesis of MALT lymphomas, emphasizing particularly their influence in disrupting the apoptotic pathway.

Dr. Zucca reviews findings suggesting that MALT lymphoma is an antigen driven neoplasm. He also presents specific guidelines for treatment of gastric lymphomas trying to shed some light on the amazingly inconsistent and confusing data in the literature.

Taking advantage on the more than 300 non-gastric MALT lymphomas collected by the International Extranodal Lymphoma Study Group (ILESG), Dr. Cavalli compares gastric lymphomas with those arising in many other sites.

Overall, the data presented in this session will underline the fact, that MALT lymphomas are characterized by some unique biological properties.