Showing papers on "Literature survey published in 1998"

Outsourcing of logistics functions: a literature survey

Abstract: Recent times have witnessed a heightened global interest in outsourcing of logistics functions. This is indicated by the volume of writings on the subject in various scholarly journals, trade publications and popular magazines. However, efforts to organize them in an integrated body of knowledge appear to be very limited. Keeping this in view, this paper makes an attempt to develop a comprehensive literature on outsourcing based on more than 100 published articles, papers and books on the subject.

Shape-memory materials and hybrid composites for smart systems: Part I Shape-memory materials

Abstract: A review is presented of the current research and development of shape-memory materials, including shape-memory alloys, shape-memory ceramics and shape-memory polymers. The shape-memory materials exhibit some novel performances, such as sensoring (thermal, stress or field), large-stroke actuation, high damping, adaptive responses, shape memory and superelasticity capability, which can be utilized in various engineering approaches to smart systems. Based on an extensive literature survey, the various shape-memory materials are outlined, with special attention to the recently developed or emerged materials. The basic phenomena in the materials, that is, the stimulus-induced phase transformations which result in the unique performance and govern the remarkable changes in properties of the materials, are systematically lineated. The remaining technical barriers, and the challenges to improve the present materials system and develop a new shape memory materials are discussed.

Seed dispersal and the holocene migration of woodland herbs

Abstract: The distribution of many woodland herbs extends 1000-2000 km in a north- south direction, yet the majority of these species grow clonally, have little recruitment by seed, and possess no obvious mechanism for long-distance seed dispersal. Although aware that woodland herbs disperse poorly, ecologists have tacitly assumed that, given long periods of time, even small dispersal distances would allow woodland herbs to colonize the vast geographic region they now occupy. We examined this assumption for the understory herb Asarum canadense. To estimate long-term rates of spread by seed, we calibrated seed- dispersal diffusion models with life history data and with data on seed carries by ants. We supplemented our field observations and modeling results forA. canadensewith a literature survey on the dispersal capabilities of other plant species. Ants transported A. canadense seeds up to 35 m, the largest distance ants are known to move the seeds of any woodland herb. Empirically calibrated diffusion models indicated that over the last 16 000 yr A. canadense should only have traveled 10-11 km from its glacial refugia. In actuality, A. canadense moved hundreds of kilometers during this time. Models that examined the tail of A. canadense's seed-dispersal curve indicated that oc- casional dispersal events had to have a high frequency ($0.001 on a per seed basis) and a large magnitude (dispersal distance .1 km) for A. canadense to have traveled over 200 km in 16 000 yr. The literature survey showed that most woodland herbs and many other forest, desert, coastal, and open-habitat plant species have limited seed-dispersal capabil- ities, similar to those in A. canadense. We conclude that woodland herbs, as well as many other plants, disperse so slowly that there is no documented mechanism by which most of these species could have reached their present geographical range since the last glacial maximum. This suggests that occasional events leading to long-distance dispersal dominate the Holocene colonization of northern temperate forest by woodland herbs, and this, in turn, has implications for issues ranging from the importance of genetic analyses to the structure of metapopulation models.

(Not) Hanging on the Telephone: Payment Systems in the New Sweatshops

Abstract: 'The ultimate objective of empirical work on incentives should be to find out why firms use the compensation systems they doahuge advances in our understanding could be made by a concerted effort to collect data on contracts.'' So concludes the 1998 Journal of Economic Literature survey on compensation systems. This paper does just that. It presents very detailed case study evidence on contracts in four organizations, three of which are call centres, the fastest growing sector of employment in the UK. This evidence is used to test predictions from the New Economics of Personnel (NEP) concerning the incidence of payment systems. We also contrast and test predictions from NEP with those of the earlier British Institutional School, which anticipated many of NEP''s ideas on payment systems. Variations in the ratio of performance-related to basic pay among our organizations can, broadly, be explained by the costs and benefits of monitoring inputs and measuring output, which comprises the core of NEP. Indeed, the monitoring of our case study employees is the theme which binds the paper together u for call centres Jeremy Bentham''s 1791 Panopticon was truly the vision of the future.

Stratified Atmospheric Boundary Layers and Breakdown of Models

Abstract: The goal of this study is to assess complications in atmospheric stable boundary layers which are not included in numerical models of the stably stratified boundary layer and to provide a formulation of surface fluxes for use in numerical models. Based on an extensive interpretive literature survey and new eddy correlation data for the stable boundary layer, this study defines two prototype stable boundary layers: the weakly stable case and the very stable case. The weakly stable boundary layer is amenable to existing models. The very stable boundary layer eludes modeling attempts due to breakdown of existing formulations of turbulence and due to features found in the atmosphere which are not normally included in models. The latter includes clear-air radiative cooling, low-level jets, surface heterogeneity, gravity waves, meandering motions, and other mesoscale motions which propagate from outside the local domain. While these mechanisms are not essential to understanding idealized or laboratory versions of the stable boundary layer, they complicate comparisons of numerical models and theories with actual atmospheric boundary layers. Statistics which describe various features of the stable boundary layer are offered for future comparison with modeling results.

Stability and robust stability of time-delay systems: A guided tour

Abstract: In this chapter, some recent stability and robust stability results on linear time-delay systems are outlined The goal of this guided tour is to give (without entering the details) a wide overview of the state of the art of the techniques encountered in time-delay system stability problems In particular, two specific stability problems with respect to delay (delay-independent and respectively delay-dependent) are analyzed and some references where the reader can find more details and proofs are pointed out The references list is not intended to give a complete literature survey, but rather to be a source for a more complete bibliography In order to simplify the presentation several examples have been considered

Fuzzy set theory applications in production management research: a literature survey

Abstract: Fuzzy set theory has been used to model systems that are hard to define precisely. As a methodology, fuzzy set theory incorporates imprecision and subjectivity into the model formulation and solution process. Fuzzy set theory represents an attractive tool to aid research in production management when the dynamics of the production environment limit the specification of model objectives, constraints and the precise measurement of model parameters. This paper provides a survey of the application of fuzzy set theory in production management research. The literature review that we compiled consists of 73 journal articles and nine books. A classification scheme for fuzzy applications in production management research is defined. We also identify selected bibliographies on fuzzy sets and applications.

Powder/processing/structure relationships in WC-Co thermal spray coatings: A review of the published literature

Abstract: Thermally sprayed coatings based on tungsten carbide are widely used but not yet fully understood, particularly with regard to the chemical, microstructural, and phase changes that occur during spraying and their influence on properties such as wear resistance. The available literature on thermally sprayed WC-Co coatings is considerable, but it is generally difficult to synthesize all of the findings to obtain a comprehensive understanding of the subject. This is due to the many different starting powders, spray system types, spray parameters, and other variables that influence the coating structures and cause difficulties when comparing results from different workers. The purpose of this review is to identify broad trends in the powder/processing/structure relationships of WC-Co coatings, classified according to powder type and spray method. Detailed comparisons of coating microstructures, powder phase compositions and coating phase compositions as reported by different researchers are given in tabular form and discussed. The emphasis is on the phase changes that occur during spraying. This review concerns only WC-12% Co and WC-17% Co coatings, and contrasts the coatings obtained from the cast and crushed, sintered and crushed, and agglomerated and densified powder types. Properties such as hardness, wear, or corrosion resistance are not reviewed here.

Evaluation of Self-Starting Vertical Axis Wind Turbines for Stand-Alone Applications

Abstract: There is an urgent need for economical, clean, sustainable energy supplies, not only in densely populated areas where electricity grids are appropriate, but also in rural areas where stand-alone power supply systems are often more suitable. Although electrical power supply is very versatile and convenient, it introduces unnecessary complexity for some off-grid applications where direct mechanical shaft power can conveniently be provided by a wind turbine. Wind energy is one of the more promising renewable energy sources. Most wind turbines are of the horizontal axis type, but vertical axis wind turbines or VAWTs have some advantages for direct mechanical drive applications. They need no tail or yaw mechanism to orient them into the wind and power is easily transmitted via a vertical shaft to a load at ground level. Blades may be of uniform section and untwisted, making them relatively easy to fabricate or extrude, unlike the blades of horizontal axis wind turbines (HAWTs) which should be twisted and tapered for optimum performance. Savonius rotor VAWTs are simple and may have a place where the power requirement is only a few Watts, but they are inefficient and uneconomical for applications with larger power requirements. VAWTs based on the Darrieus rotor principle are potentially more efficient and more economical, but those with fixed pitch blades have hitherto been regarded as unsuitable for stand-alone use due to their lack of starting torque and low speed torque. This starting torque problem can be overcome by using variable pitch blades, but most existing variable pitch VAWTs, variously known as giromills or cycloturbines, need wind direction sensors, microprocessors and servomotors to control the blade pitch, making them impracticable for stand-alone, non-electrical applications. A simpler but less well known concept is passive or self-acting variable pitch in which the blades are free to pitch under the combined action of aerodynamic and inertial forces in such a way that a favourable blade angle of attack is maintained without the complexity of conventional variable pitch systems. Several fonns of self-acting variable pitch VAWTs or SAPVAWTs have been described in the literature, several patents exist for variants on the concept, and at least two companies world-wide have attempted to commercialise their designs. However the aerodynamic behaviour of these devices has been little understood and most designs appear to have been based on nothing more than a qualitative appreciation of the potential advantages of the concept. This thesis assesses the potential of both fixed and passive variable pitch vertical axis wind turbines to provide economical stand-alone power for direct mechanical drive applications. It is shown that the starting torque and low speed torque problems of VAWTs can be overcome either by passive variable pitch or by a combination of suitable blade aerofoil sections, either rigid or flexible, and transmissions which unload the rotor at low speeds so that high starting torque is not necessary. The work done for this thesis is made up of a sequence of stages, each following logically from the previous one: 1. Several tasks have been identified which could be performed effectively by a self-starting vertical axis wind turbine using direct mechanical drive. These include, a. pumping water, b. purifying and/or desalinating water by reverse osmosis, c. heating and cooling using vapour compression heat pumps, d. mixing and aerating water bodies and e. heating water by fluid turbulence. Thus it is apparent that such a system has the potential to make a useful contribution to society. 2. A literature survey of existing VAWT designs has been carried out to assess whether any are suitable for these applications. 3. As no suitable existing design was identified, an improved form of SAPVAWT has been developed and patented. 4. To optimise the performance of the improved SAPVAWT, a mathematical model has been developed in collaboration with Mr Leo Lazauskas of the University of Adelaide (see Kirke and Lazauskas, 1991, Lazauskas and Kirke, 1992). As far as the author of the present thesis is aware, this is the only existing mathematical model able to predict the performance of this particular type of SAPVAWT, and one of only two worldwide which model SAPVAWTs. 5. In order to use the mathematical model to predict the performance of a given SAPVAWT, it is necessary to have lift, drag and moment data for the aerofoil profile to be used, over a wide range of incidence and Reynolds numbers. A literature search has revealed large gaps in the existing data. 6. Wind tunnel testing has been carried out to assess the effect of camber on the performance of one set of NACA sections at low Reynolds number, and performance figures for other sections have been estimated by interpolation from existing data. 7. Using the assembled aerofoil data, both experimental and estimated, the mathematical model has been used to predict the performance of both fixed and variable pitch VAWTs. It has been found to predict correctly the performance of known fixed pitch VAWTs and has then been used to predict the performance of fixed pitch VAWTs with cambered blades using newly developed profiles that exhibit superior characteristics at low Reynolds numbers. Results indicate that fixed pitch VAWTs using these blade sections should self-start reliably. 8. To validate the mathematical model predictions for self-acting variable pitch, a two metre diameter physical model has been built and tested in a wind tunnel, and acceptable agreement has been obtained between predicted and measured performance. 9. To demonstrate the performance of a SAP VA WT under field conditions, a six metre diameter turbine has been designed, fabricated, erected and tested. 10. Because a prime mover such as a wind turbine is of no use unless it drives a toad, particular attention has been paid to the behaviour of complete systems, including the wind turbine, the transmission and the load. It is concluded that VAWTs with the improved self-starting and low speed torque characteristics described in this thesis have considerable potential in stand-alone, direct mechanical drive applications.

Effect of hyperbaric oxygen therapy in comparison to conventional or placebo therapy or no treatment in idiopathic sudden hearing loss, acoustic trauma, noise-induced hearing loss and tinnitus. A literature survey.

Abstract: With the published clinical data to hand on the therapeutic results of patients with idiopathic sudden hearing loss, acoustic trauma or noise-induced hearing loss, it may be confirmed that 65% of those polypragmatically treated patients demonstrated a hearing improvement of 19 +/- 4 dB In 35% of the cases, no hearing improvement was detected independent of the drugs administered This corresponds to the results obtained from placebo-treated patients who demonstrated a hearing improvement of 20 +/- 2 dB in 61% of cases and no hearing gain in 39% of cases (fig 1) A different set of results was obtained from patients with a hearing loss who were treated either with prednisolone or placebo The percentage of patients who achieved normal hearing again in the placebo-treated group amounted to 31% and 38% and in the verum-treated group 50% and 78% It may be concluded that a placebo therapy is equally effective to that of all nonsteroidal drugs Problems arise when comparing non-treated patients since information on spontaneous remission rates differs greatly in the references, ie between 25-68% for spontaneous full remissions and 47-89% for spontaneous partial remissions From a statistical view, 35% and 39% of patients experienced no success with nonsteroidal drugs or placebo, respectively These patients can still be helped with HBO therapy 18 patients only underwent primary HBO therapy In all other 50 studies evaluated here with a total of 4, 109 patients suffering from idiopathic sudden hearing loss, acoustic trauma or noise-induced hearing loss and/or tinnitus, HBO therapy was administered as a secondary therapy, ie following unsuccessful conventional therapy If the onset of affliction was more than 2 weeks but no longer than 6 weeks, one half of the cases showed a marked hearing gain (in at least 3 frequencies of more than 20 dB), one-third showed a moderate improvement (10-20 dB) and 13% showed no hearing improvement at all (fig 2) 4% no longer experienced tinnitus, 813% observed an intensity decrease and 12% an intensity increase of their tinnitus condition 135% remained unchanged (fig 2) If HBO therapy was administered at a later stage, but still within 3 months following onset of affliction, 13% showed a definite improvement in hearing, 25% a moderate improvement and 62% no improvement at all 7% no longer suffered from tinnitus, 44% reported an intensity decrease, a similar percentage noticed no change and 5% a temporary deterioration of their tinnitus condition If the onset of affliction was longer than 3 months up to several years, no hearing improvement can be expected in the majority of patients (fig 3); however, one third of the cases reported an intensity decrease of tinnitus, 60-62% reported no change and 4-7% noticed a temporary intensity increase (fig 4) In conclusion, it may be deduced that HBO therapy is recommended and warranted in those patients with idiopathic sudden deafness, acoustic trauma or noise-induced hearing loss within 3 months after onset of disorder

Estimation of Origin-Destination Matrices Using Traffic Counts - A Literature Survey

Abstract: The Origin-Destination (OD) matrix is important in describing transportation in a region. This matrix has information on the travel and transportation made between different zones of a region. The OD matrix can be estimated using traffic counts on links in the transport network and other available information. This information on the travel is often contained in a "target OD matrix." The target OD matrix my be an old (probably outdated) matrix or a result from a sample survey. From these two data sources various approaches to estimating an OD matrix has been developed and tested. This survey provides a survey of generic approaches and an annotated bibliography of some individual contributions. Some models and methods are in another paper tested in medium sized applications in a congested region.

Can extensional viscosity be measured with opposed-nozzle devices?

Abstract: Opposed-nozzle devices are widely used to try to measure the extensional viscosity of low-viscosity liquids. A thorough literature survey shows that there are still several unanswered questions on the relationship between the quantity measured in opposed-nozzle devices and the “true” extensional viscosity of the liquids. In addition to extensional stresses, opposed nozzle measurements are influenced by dynamic pressure, shear on the nozzles, and liquid inertia. Therefore the ratio of the apparent extensional viscosity that is measured to the shear viscosity that is independently measured is greater than three even for Newtonian liquids. The effect of inertia on the extensional measurements is analyzed by computer-aided solution of the Navier-Stokes system, and by experiments on low-viscosity Newtonian liquids (1 mPa s

Natural and anthropogenic dispersal mechanisms in the marine environment: a study using cheilostome Bryozoa

Abstract: The global geographic ranges occupied by 197 species of cheilostomate Bryozoa found in British waters were obtained by a literature survey. Morphological grade, larval mode, environmental tolerance, species abundance and the ability to raft and to foul shipping were all investigated as traits potentially able to affect the geographic ranges of these bryozoan species. When considered independently all variables except larval mode had a significant correlation with the geographic range occupied by a species. However, when controlling for the potentially confounding effects of the other covariates, only the ability to foul or raft and species abundance had a significant effect on median geographic range and only fouling and abundance had a significant effect over global ranges. The strength of the association between fouling ability and range suggests that transport upon the hulls of ships is a very important dispersal mechanism for bryozoans, as it is thought to be also for various other marine taxa. Potential long-term (evolutionary) consequences of increased ranges brought about by anthropogenic mechanisms are discussed.

Emissions Scenarios Database and Review of Scenarios

Abstract: This paper reviews and analyzes more than 400 scenarios of global and regional greenhouse gas emissions and their main driving forces - population, economy, energy intensity, and carbon intensity - drawn from an extensive literature survey and summarized in a database. This new and growing database is available online, which makes summary statistics on these scenarios widely available. The scenarios in the database were collected from almost 200 different literature sources and other scenario evaluation activities. The ultimate objective of the database is to include all relevant global and regional emissions scenarios. This paper shows how the database can be utilized for the analysis of greenhouse gas emissions ranges across the scenarios in the literature and for the analysis of their main driving forces. The scenarios in the database display a large range of future greenhouse gas emissions. Part of the range can be attributed to the different methods and models used to formulate the scenarios, which include simple spreadsheet models, macroeconomic models and systems-engineering models. However, most of the range is due to differences in the input assumptions for the scenarios, in particular of the main scenario driving forces. Special emphasis is given to an analysis of medians and ranges of scenario distributions and the distributions of the main scenario driving forces in the database. The analysis shows that the range for projected population increase in the world, across the scenarios in the database, is the smallest of all main driving forces (about a factor of 3 in 2100). The range of economic growth, measured by the gross world product, and the range of primary energy consumption vary by a factor of 10 in 2100. Carbon intensity of energy, an indicator of the degree of technological change, varies by nearly two orders of magnitude in the year 2100. In addition, this paper presents the first attempt to analyze the relationships among the main scenario driving forces. Subsequent papers in this special issue give further analyses of the relationships among the main scenario driving forces and their other relevant characteristics.

From the de Broglie to Visible Wavelengths: Manipulating Electrons and Photons With Colloids

Abstract: Because of their size and ability to selforganize, colloidal particles are ideal building blocks for the creation of three-dimensional (3D) structures that can have feature sizes of the order of the wavelength of electrons, photons, or both. This article is too short to provide an extensive literature survey but instead will give some illustrative examples, based on work of the author and co-workers, of how specially developed core-shell particles might be organized on a 3D lattice. These examples are only intended to give an impression of how colloidal-particle systems can be used in the design of new materials with interesting photonic properties.Generally particles are considered colloidal if their size is between several nm and several μm. This range is more or less defined by the importance of Brownian motion—that is, the irregular, overdamped, random displacements the particles make as a result of the not completely averaged-out bombardment of solvent (or gas) molecules. Consequently the lower size range is determined by the size of the solvent molecules. Compared to the particle size, the solvent molecules need to be so small that the time scales of the solvent molecules and particles are so far apart that the solvent molecules can be “integrated out” in a description of the particles. If such a description holds, the solvent can be approximated well by a continuum. The upper size limit is determined by the size at which external fields, like gravity, start to overshadow the effects of Brownian motion.

Needle-track metastasis after transthoracic needle biopsy.

Abstract: Metastasis along the needle track (NTM) after a transthoracic needle biopsy (TNB) is considered a very rare complication. A survey of the membership of the Society of Thoracic Radiology and a review of the English-language literature were conducted to assess the incidence of this complication and its predisposing factors and natural history. A questionnaire was sent to all radiology departments in the United States and Canada that had a senior member of the Society of Thoracic Radiology. The total number of TNB between 1978 and 1993 and occurrences of NTM were elicited. If an NTM was encountered, information on the size of the nodule, proximity to the pleura, histology, size of the biopsy needle, and the interval between biopsy and NTM and outcome of the patient was elicited. The incidence of NTM was estimated using binomial proportions. Results of the literature survey were tabulated to provide similar information. One hundred sixty-five questionnaires were mailed and 75 responses were received. Approximately 68,346 TNB were reported. Five departments reported a total of eight NTM, resulting in an incidence of 0.012%. The average interval between TNB and NTM was 2.6 months. There were no predictable risk factors. The outcome was known in only 11 patients; 4 patients died by the time of reporting (2 after 14 months and 1 each after 6 and 9 months). From the results of this survey, the incidence of NTM after TNB is approximately 0.012%. This small risk is random and unavoidable.

State of the Art Literature Survey on Disassembly Planning

Abstract: In this paper, the state of the art of disassembly planning is detailed to the best of the authors knowledge. Covered are issues that have particular relevance to disassembly planning, from product representation, to task analysis, task representation, sequencing, clus tering, life cycle engineering issues, and cost estimation. Materials data requirement issues and some practical applications in disassembly plants are discussed In conclusion, this paper details future research with the aim of developing a robust and effective disassembly plan ning methodology This will be based upon task actuation and the minimisation of components requiring assessment by the plan.

Foreign investment in East Asia: A survey

Abstract: This article updates the May 1989 literature survey on foreign direct investment (FDI) in the East Asian region published in this journal. Following an overview of trends of FDI in the 1990s, it focuses on three key issues: the impact of the recent Asian economic crisis on FDI inflow relative to other forms of capital inflows; the link between FDI and trade; and technology transfer and adaptation. It is too early to discern the implications of the crisis for host-country policies and investment decisions of multinational corporations, but the indications are that FDI will continue to play a pivotal role in economic transformation, and in regional and global economic integration.

Review Shape-memory materials and hybrid composites for smart systems Part I Shape-memory materials

Abstract: A review is presented of the current research and development of shape-memory materials, including shape-memory alloys, shape-memory ceramics and shape-memory polymers. The shape-memorymaterials exhibit some novel performances,such as sensoring (thermal, stress or field), large-stroke actuation, high damping, adaptive responses, shape memory and superelasticity capability, which can be utilized in various engineering approaches to smart systems. Based on an extensive literature survey, the various shape-memory materials are outlined, with special attention to the recently developed or emerged materials. The basic phenomena in the materials, that is, the stimulus-induced phase transformationswhich result in the unique performanceand govern the remarkablechanges in properties of the materials, are systematically lineated. The remaining technical barriers, and the challenges to improve the present materials system and develop a new shape memory materials are discussed. a 1998 Kluwer Academic Publishers

Chromosome aberration assays in Crepis for the study of environmental mutagens.

Abstract: From a literature survey, 117 chemicals are tabulated that have been assayed in 179 assays for their clastogenic effects in Pisum. Of the 117 chemicals that have been assayed, 65 are reported at giving a positive reaction (i.e. causing chromosome aberrations), 30 positive with a dose response, five borderline positive. Seventeen chemicals gave a negative response. Eighty-one percent of the chemicals gave a definite positive response. A c-mitotic effect was detected from treatment with 17 chemicals. In addition to the above tabulation of chemicals, 39 chemicals have been reported with an antimitotic effect. Thirteen assays have been recorded for five types of radiation, which with the exception of ultrasound reacted positively. The results of assays with 38 chemicals and/or radiations in combined treatments, as well as 15 chemicals and three types of radiations that induce somatic mutations are tabulated. The Pisum sativum (2n=14) bioassay has been shown to be a very good plant bioassay for assessing chromosome damage both in mitosis and meiosis for somatic mutations induced by chemicals, radiations, and environmental pollutants. For some chemicals, the Pisum assay is not as sensitive in assessing clastogenicity as the Allium assay, although this should be considered in relative terms. Pisum fulvum (2n=14) has been used in clastogenic studies also, but to a much lesser extent.

Solid state chemistry of Ruddlesden-Popper type complex oxides

Abstract: Various criteria of formation of perovskites and K2NiF4-type compounds, which are the end members of homologous Ruddlesden-Popper series of phases, have been discussed. RP-phases show some general trends in their physical properties. Literature survey of the formation of these phases, their properties, and effect of oxygen stoichiometry and doping is presented. Some conditions for their synthesis are also described.

Regeneration Processes in the Kidney after Acute Injury: Role of Infiltrating Cells

Abstract: The transient presence of infiltrated leukocytes in the kidney during acute renal failure as well as the location of these cells within the renal interstitium suggest their association with tubular injury and/or regeneration To date, however, neither a positive nor a negative contribution of these cells to the pathophysiology of this disease could be unambiguously demonstrated Ill-defined methods for identifying interstitial leukocytes have added to the controversy concerning the role of inflammatory cells in renal regeneration The current literature survey presents a qualitative description of the renal interstitial accumulation of leukocytes as observed in some acute renal failure models, with special attention to those displaying acute tubular necrosis of particular nephron subsegments We conclude that lethal or sublethal injury to renal tubular epithelial cells following toxic or ischemic insults leads to the manifestation of an interstitial mononuclear cell infiltrate Whereas macrophages and T lymphocytes almost invariably take part, the former being the dominant cell population with respect to both magnitude and presence over time, polymorphonuclear cells seem to be significantly increased only in the case of pyelonephritis Infiltrating cells have often been regarded rather harmful to the tissue, mainly due to the quite well understood injuring capacity of the latter On the other hand, we speculate mononuclear leukocytes through their potential of producing different cytokines and growth factors (FGF, TGF-α, EGF-like, IL-2, etc) might well play an initiating and mediating role in renal regeneration after acute tubular necrosis Therefore, the role of infiltrating leukocytes in the injury/regeneration process during acute renal failure remains highly controversial and should be further elucidated