bluuebunny/crossref_metadata_2025 huggingface dataset:
PROGRESS COMMERCIALIZING SOLAR-ELECTRIC POWER SYSTEMS
Authors: Dracker Raymond , De Laquil III Pascal
Published: July 2002

▪ Abstract  The commercial status of the principal solar electric technologies—photovoltaic and solar thermal—is reviewed. Current and near-term market niches are identified, and projected longer-term markets are explored along with the key strategies for achieving them, including technological breakthroughs, manufacturing developments, economies of scale and mass production, and market creation. Market barriers and public policy impacts on commercialization are discussed.
DRINKING WATER IN DEVELOPING COUNTRIES
Authors: Gadgil Ashok
Published: July 2002

▪ Abstract  Safe drinking water remains inaccessible for about 1.1 billion people in the world, and the hourly toll from biological contamination of drinking water is 400 deaths of children (below age 5). This paper reviews the general guidelines for drinking water quality and the scale of the global problem. It reviews the various water disinfection technologies that may be applicable to achieve the desired quality of drinking water in developing countries. It then summarizes financing problems that deter extending access to safe drinking water to the unserved population and identifies feasible policy positions for enhancing availability of drinking water in these countries.
ENGINEERING-ECONOMIC STUDIES OF ENERGY TECHNOLOGIES TO REDUCE GREENHOUSE GAS EMISSIONS: Opportunities and Challenges
Authors: Brown Marilyn A. , Levine Mark D. , Romm Joseph P. , Rosenfeld Arthur H. , Koomey Jonathan G.
Published: July 2002

▪ Abstract  This paper compares the results of four recent engineering-economic studies of the potential for energy technologies to reduce greenhouse gas emissions. The review includes a sector-by-sector assessment of specific technology opportunities and their costs, as estimated by (a) five National Laboratories, (b) the Tellus Institute, (c) the National Academy of Sciences, and (d) the Office of Technology Assessment. These studies document that numerous cost-effective, energy-efficient technologies remain underutilized in each end-use sector of the economy. Supply-side options, on the other hand, are generally found to involve some net costs. Demand- and supply-side options benefit from being pursued concurrently because of various interaction effects. In combination, large carbon reductions are possible at incremental costs that are less than the value of the energy saved. An aggressive national commitment involving some combination of targeted tax incentives, emissions trading, and non-price policies is needed to exploit these carbon reduction opportunities.
On the Road to Global Ecology
Authors: Mooney H. A.
Published: July 2002

This review presents a personal view of the development of plant physiological ecology, the science of studying biological diversity, and the functioning of the Earth as a system. The need for interaction among these disciplines is becoming increasingly urgent as we are faced with the challenge of “managing” the Earth system that is increasingly impacted by the activities of humans.
CARBON DIOXIDE EMISSIONS FROM THE GLOBAL CEMENT INDUSTRY
Authors: Worrell Ernst , Price Lynn , Martin Nathan , Hendriks Chris , Meida Leticia Ozawa
Published: July 2002

▪ Abstract  The cement industry contributes about 5% to global anthropogenic CO2 emissions, making the cement industry an important sector for CO2-emission mitigation strategies. CO2 is emitted from the calcination process of limestone, from combustion of fuels in the kiln, as well as from power generation. In this paper, we review the total CO2 emissions from cement making, including process and energy-related emissions. Currently, most available data only includes the process emissions. We also discuss CO2 emission mitigation options for the cement industry. Estimated total carbon emissions from cement production in 1994 were 307 million metric tons of carbon (MtC), 160 MtC from process carbon emissions, and 147 MtC from energy use. Overall, the top 10 cement-producing countries in 1994 accounted for 63% of global carbon emissions from cement production. The average intensity of carbon dioxide emissions from total global cement production is 222 kg of C/t of cement. Emission mitigation options include energy efficiency improvement, new processes, a shift to low carbon fuels, application of waste fuels, increased use of additives in cement making, and, eventually, alternative cements and CO2 removal from flue gases in clinker kilns.
Alternatives to Methyl Bromide Treatments for Stored-Product and Quarantine Insects
Authors: Fields Paul G. , White Noel D. G.
Published: July 2002

▪ Abstract  Methyl bromide is used to control insects as a space fumigant in flour and feed mills and ship holds, as a product fumigant for some fruit and cereals, and for general quarantine purposes. Methyl bromide acts rapidly, controlling insects in less than 48 h in space fumigations, and it has a wide spectrum of activity, controlling not only insects but also nematodes and plant-pathogenic microbes. This chemical will be banned in 2005 in developed countries, except for exceptional quarantine purposes, because it depletes ozone in the atmosphere. Many alternatives have been tested as replacements for methyl bromide, from physical control methods such as heat, cold, and sanitation to fumigant replacements such as phosphine, sulfuryl fluoride, and carbonyl sulfide, among others. Individual situations will require their own type of pest control techniques, but the most promising include integrated pest management tactics and combinations of treatments such as phosphine, carbon dioxide, and heat.
Competitive Displacement Among Insects and Arachnids
Authors: Reitz Stuart R. , Trumble John T.
Published: July 2002

▪ Abstract  Competitive displacement is the most severe outcome of interspecific competition. For the purposes of this review, we define this type of displacement as the removal of a formerly established species from a habitat as a result of direct or indirect competitive interactions with another species. We reviewed the literature for recent putative cases of competitive displacement among insects and arachnids and assessed the evidence for the role of interspecific competition in these displacements. We found evidence for mechanisms of both exploitation and interference competition operating in these cases of competitive displacement. Many of the cases that we identified involve the operation of more than one competitive mechanism, and many cases were mediated by other noncompetitive factors. Most, but not all, of these displacements occurred between closely related species. In the majority of cases, exotic species displaced native species or previously established exotic species, often in anthropogenically-altered habitats. The cases that we identified have occurred across a broad range of taxa and environments. Therefore we suggest that competitive displacement has the potential to be a widespread phenomenon, and the frequency of these displacement events may increase, given the ever-increasing degree of anthropogenic changes to the environment. A greater awareness of competitive displacement events should lead to more studies documenting the relative importance of key factors and developing hypotheses that explain observed patterns.
Can Generalist Predators be Effective Biocontrol Agents?
Authors: Symondson W. O. C. , Sunderland K. D. , Greenstone M. H.
Published: July 2002

▪ Abstract  Theoretical developments are helping us to comprehend the basic parameters governing the dynamics of the interactions between generalist predators and their many pest and nonpest prey. In practice, however, inter- and intraspecific interactions between generalist predators, and between the predators and their prey, within multispecies systems under the influence of rapidly changing biotic and abiotic variables are difficult to predict. We discuss trade-offs between the relative merits of specialists and generalists that allow both to be effective, and often complementary, under different circumstances. A review of manipulative field studies showed that in ∼75% of cases, generalist predators, whether single species or species assemblages, reduced pest numbers significantly. Techniques for manipulating predator numbers to enhance pest control at different scales are discussed. We now need to find ways of disentangling the factors influencing positive and negative interactions within natural enemy communities in order to optimize beneficial synergies leading to pest control.
Host Plant Quality and Fecundity in Herbivorous Insects
Authors: Awmack Caroline S. , Leather Simon R.
Published: July 2002

▪ Abstract  Host plant quality is a key determinant of the fecundity of herbivorous insects. Components of host plant quality (such as carbon, nitrogen, and defensive metabolites) directly affect potential and achieved herbivore fecundity. The responses of insect herbivores to changes in host plant quality vary within and between feeding guilds. Host plant quality also affects insect reproductive strategies: Egg size and quality, the allocation of resources to eggs, and the choice of oviposition sites may all be influenced by plant quality, as may egg or embryo resorption on poor-quality hosts. Many insect herbivores change the quality of their host plants, affecting both inter- and intraspecific interactions. Higher–trophic level interactions, such as the performance of predators and parasitoids, may also be affected by host plant quality. We conclude that host plant quality affects the fecundity of herbivorous insects at both the individual and the population scale.
DIFFUSE-INTERFACE METHODS IN FLUID MECHANICS
Authors: Anderson D. M. , McFadden G. B. , Wheeler A. A.
Published: July 2002

▪ Abstract  We review the development of diffuse-interface models of hydrodynamics and their application to a wide variety of interfacial phenomena. These models have been applied successfully to situations in which the physical phenomena of interest have a length scale commensurate with the thickness of the interfacial region (e.g. near-critical interfacial phenomena or small-scale flows such as those occurring near contact lines) and fluid flows involving large interface deformations and/or topological changes (e.g. breakup and coalescence events associated with fluid jets, droplets, and large-deformation waves). We discuss the issues involved in formulating diffuse-interface models for single-component and binary fluids. Recent applications and computations using these models are discussed in each case. Further, we address issues including sharp-interface analyses that relate these models to the classical free-boundary problem, computational approaches to describe interfacial phenomena, and models of fully miscible fluids.
MICRO-ELECTRO-MECHANICAL-SYSTEMS (MEMS) AND FLUID FLOWS
Authors: Ho Chih-Ming , Tai Yu-Chong
Published: July 2002

▪ Abstract  The micromachining technology that emerged in the late 1980s can provide micron-sized sensors and actuators. These micro transducers are able to be integrated with signal conditioning and processing circuitry to form micro-electro-mechanical-systems (MEMS) that can perform real-time distributed control. This capability opens up a new territory for flow control research. On the other hand, surface effects dominate the fluid flowing through these miniature mechanical devices because of the large surface-to-volume ratio in micron-scale configurations. We need to reexamine the surface forces in the momentum equation. Owing to their smallness, gas flows experience large Knudsen numbers, and therefore boundary conditions need to be modified. Besides being an enabling technology, MEMS also provide many challenges for fundamental flow-science research.
VORTEX PARADIGM FOR ACCELERATED INHOMOGENEOUS FLOWS: Visiometrics for the Rayleigh-Taylor and Richtmyer-Meshkov Environments
Authors: Zabusky Norman J.
Published: July 2002

▪ Abstract  We illustrate how cogent visiometrics can provide peak insights that lead to pathways for discovery through computer simulation. This process includes visualizing, quantifying, and tracking evolving coherent structure morphologies. We use the vortex paradigm ( Hawley & Zabusky 1989 ) to guide, interpret, and model phenomena arising in numerical simulations of accelerated inhomogeneous flows, e.g. Richtmyer-Meshkov shock-interface and shock-bubble environments and Rayleigh-Taylor environments. Much of this work is available on the Internet at the sites of my collaborators, A Kotelnikov, J Ray, and R Samtaney, at our Vizlab URL, http://vizlab.rutgers.edu/vizlab.html.
STEADY STREAMING
Authors: Riley N
Published: July 2002

▪ Abstract  The time-average of a fluctuating flow often results in a nonzero mean. Such steady streaming may result directly from the action of an oscillatory nonconservative body force or, if such a force is conservative, indirectly through the action of Reynolds stresses in the main body of the fluid or in thin boundary layers at no-slip boundaries. A theory for such streaming flows is developed for homogeneous fluids. For flows with a free surface it is demonstrated that a mechanism for steady streaming exists even in an inviscid fluid. Diverse areas in which steady streaming flows may be important are discussed.
CAVITATION IN VORTICAL FLOWS
Authors: Arndt Roger E.A.
Published: July 2002

▪ Abstract  Cavitation in vortical structures is a common, albeit complex, problem in engineering applications. Cavitating vortical structures can be found on the blade surfaces, in the clearance passages, and at the hubs of various types of turbomachinery. Cavitating microvortices at the trailing edge of attached sheet cavitation can be highly erosive. Cavitating hub vortices in the draft tubes of hydroturbines can cause major surges and power swings. There is also mounting evidence that vortex cavitation is a dominant factor in the inception process in a broad range of turbulent flows. Most research has focused on the inception process, with limited attention paid to developed vortex cavitation. Wave-like disturbances on the surfaces of vapor cores are an important feature. Vortex core instabilities in microvortices are found to be important factors in the erosion mechanisms associated with sheet/cloud cavitation. Under certain circumstances, intense sound at discrete frequencies can result from a coupling between tip vortex disturbances and oscillating sheet cavitation. Vortex breakdown phenomena that have some commonalities are also noted, as are some differences with vortex breakdown in fully wetted flow. Simple vortex models can sometimes be used to describe the cavitation process in complex turbulent flows such as bluff body wakes and in plug valves. Although a vortex model for cavitation in jets does not exist, the mechanism of inception appears to be related to the process of vortex pairing. The pairing process can produce negative peaks in pressure that can exceed the rms value by a factor of ten, sometimes exceeding the dynamic pressure by a factor of two. A new and important issue is that cavitation is not only induced in vortical structures but is also a mechanism for vorticity generation.
THE GENETICS OF DISULFIDE BOND METABOLISM
Authors: Rietsch Arne , Beckwith Jonathan
Published: July 2002

▪ Abstract  Disulfide bonds are required for the stability and function of a large number of proteins. Genetic analysis in combination with biochemical studies have elucidated the main catalysts involved in facilitating these processes in the cell. All enzymes involved in thiol-disulfide metabolism have a conserved active site that consists of two cysteine residues, separated by two intervening amino acids, the Cys-Xaa-Xaa-Cys motif. While these enzymes are capable of catalyzing both disulfide bond formation and reduction, they have evolved to perform one or the other reaction more efficiently. In the cytoplasm, multiple pathways are involved in the reduction of disulfide bonds that occur as part of the catalytic cycle of a variety of metabolic enzymes. In the bacterial periplasm, a system for the efficient introduction as well as isomerization of disulfide bonds is in place. In eukaryotes, disulfide bonds are introduced into proteins in the endoplasmic reticulum. Genetic studies have recently begun to reveal new features of this process. While the enzyme mechanisms of thiol-disulfide oxidoreductases have been the subject of much scrutiny, questions remain regarding where and when they act in vivo, their specificities, and the maintenance of the redox environment that determines their function.
Mechanisms of mRNA Surveillance in Eukaryotes
Authors: Hilleren P , Parker R
Published: July 2002

▪ Abstract  A conserved mRNA degradation system, referred to as mRNA surveillance, exists in eukaryotic cells to degrade aberrant mRNAs. A defining aspect of aberrant transcripts is that the spatial relationship between the termination codon and specific downstream sequence information has been altered. A key, yet unknown, feature of the mRNA surveillance system is how this spatial relationship is assessed in individual transcripts. Two views have emerged to describe how discrimination between proper and improper termination might occur. In the first view, a surveillance complex assembles onto the mRNA after translation termination, and scans the mRNA in a 3′ to 5′ direction for a limited distance. If specific downstream sequence information is encountered during this scanning, then the surveillance complex targets the transcript for rapid decay. An alternate view suggests that the downstream sequence information influences how translation termination occurs. This view encompasses several ideas including: (a) The architecture of the mRNP can alter the rate of key steps in translation termination; (b) the discrimination between a proper and improper termination occurs via an internal, Upf1-dependent, timing mechanism; and (c) proper termination results in the restructuring of the mRNP to a form that promotes mRNA stability. This proposed model for mRNA surveillance is similar to other systems of kinetic proofreading that monitor the accuracy of other biogenic processes such as translation and spliceosome assembly.
GENETICS OF THE MAMMALIAN CIRCADIAN SYSTEM: Photic Entrainment, Circadian Pacemaker Mechanisms, and Posttranslational Regulation
Authors: Lowrey Phillip L. , Takahashi Joseph S.
Published: July 2002

▪ Abstract  During the past four years, significant progress has been made in identifying the molecular components of the mammalian circadian clock system. An autoregulatory transcriptional feedback loop similar to that described in Drosophila appears to form the core circadian rhythm generating mechanism in mammals. Two basic helix-loop-helix (bHLH) PAS (PER-ARNT-SIM) transcription factors, CLOCK and BMAL1, form the positive elements of the system and drive transcription of three Period and two Cryptochrome genes. The protein products of these genes are components of a negative feedback complex that inhibits CLOCK and BMAL1 to close the circadian loop. In this review, we focus on three aspects of the circadian story in mammals: the genetics of the photic entrainment pathway; the molecular components of the circadian pacemaker in the hypothalamic suprachiasmatic nucleus; and the role of posttranslational regulation of circadian elements. A molecular description of the mammalian circadian system has revealed that circadian oscillations may be a fundamental property of many cells in the body and that a circadian hierarchy underlies the temporal organization of animals.
The Genomics and Genetics of Human Infectious Disease Susceptibility
Authors: Hill Adrian V.S.
Published: July 2002

A genetic basis for interindividual variation in susceptibility to human infectious diseases has been indicated by twin, adoptee, pedigree, and candidate gene studies. This has led to the identification of a small number of strong genetic associations with common variants for malaria, HIV infection, and infectious prion diseases. Numerous other genes have shown less strong associations with these and some other infectious diseases, such as tuberculosis, leprosy, and persistent hepatitis viral infections. Many immunogenetic loci influence susceptibility to several infectious pathogens. Recent genetic linkage analyses of measures of infection as well as of infectious disease, including some genome-wide scans, have found convincing evidence of genetic linkage to chromosomal regions wherein susceptibility genes have yet to be identified. These studies indicate a highly polygenic basis for susceptibility to many common infectious diseases, with some emerging examples of interaction between variants of specific polymorphic host and pathogen genes.
THE IFNγ RECEPTOR:A Paradigm for Cytokine Receptor Signaling
Authors: Bach Erika A. , Aguet Michel , Schreiber Robert D.
Published: July 2002

▪ Abstract  During the last several years, the mechanism of IFNγ-dependent signal transduction has been the focus of intense investigation. This research has recently culminated in the elucidation of a comprehensive molecular understanding of the events that underlie IFNγ-induced cellular responses. The structure and function of the IFNγ receptor have been defined. The mechanism of IFNγ signal transduction has been largely elucidated, and the physiologic relevance of this process validated. Most recently, the molecular events that link receptor ligation to signal transduction have been established. Together these insights have produced a model of IFNγ signaling that is nearly complete and that serves as a paradigm for signaling by other members of the cytokine receptor superfamily.
MECHANISMS OF PHAGOCYTOSIS IN MACROPHAGES
Authors: Aderem Alan , Underhill David M.
Published: July 2002

▪ Abstract  Phagocytosis of pathogens by macrophages initiates the innate immune response, which in turn orchestrates the adaptive response. In order to discriminate between infectious agents and self, macrophages have evolved a restricted number of phagocytic receptors, like the mannose receptor, that recognize conserved motifs on pathogens. Pathogens are also phagocytosed by complement receptors after relatively nonspecific opsonization with complement and by Fc receptors after specific opsonization with antibodies. All these receptors induce rearrangements in the actin cytoskeleton that lead to the internalization of the particle. However, important differences in the molecular mechanisms underlying phagocytosis by different receptors are now being appreciated. These include differences in the cytoskeletal elements that mediate ingestion, differences in vacuole maturation, and differences in inflammatory responses. Infectious agents, such as M. tuberculosis, Legionella pneumophila, and Salmonella typhimurium, enter macrophages via heterogeneous pathways and modify vacuolar maturation in a manner that favors their survival. Macrophages also play an important role in the recognition and clearance of apoptotic cells; a notable feature of this process is the absence of an inflammatory response.
Regulation of B Lymphocyte Responses to Foreign and Self-Antigens by the CD19/CD21 Complex
Authors: Fearon Douglas T. , Carroll Michael C. , Carroll Michael C.
Published: July 2002

The membrane protein complex CD19/CD21 couples the innate immune recognition of microbial antigens by the complement system to the activation of B cells. CD21 binds the C3d fragment of activated C3 that becomes covalently attached to targets of complement activation, and CD19 co-stimulates signaling through the antigen receptor, membrane immunoglobulin. CD21 is also expressed by follicular dendritic cells and mediates the long-term retention of antigen that is required for the maintenance of memory B cells. Understanding of the biology of this receptor complex has been enriched by analyses of genetically modified mice; these analyses have uncovered roles not only in positive responses to foreign antigens, but also in the development of tolerance to self-antigens. Studies of signal transduction have begun to determine the basis for the coreceptor activities of CD19. The integration of innate and adaptive immune recognition at this molecular site on the B cell guides the appropriate selection of antigen by adaptive immunity and emphasizes the importance of this coreceptor complex.
MAP Kinases in the Immune Response
Authors: Dong Chen , Davis Roger J. , Flavell Richard A.
Published: July 2002

MAP kinases are among the most ancient signal transduction pathways and are widely used throughout evolution in many physiological processes. In mammalian species, MAP kinases are involved in all aspects of immune responses, from the initiation phase of innate immunity, to activation of adaptive immunity, and to cell death when immune function is complete. In this review, we summarize recent progress in understanding the function and regulation of MAP kinase pathways in these phases of immune responses.
PHOTOREFRACTIVE POLYMERS
Authors: Moerner W. E. , Grunnet-Jepsen A. , Thompson C. L.
Published: July 2002

▪ Abstract  Rapid advances in the field of photorefractive polymers and composites have in the brief time since their inception in 1991 led to the development of high-performance materials with refractive index modulations approaching 0.01, dif-fraction efficiencies close to 100%, and net two-beam coupling gain coefficients exceeding 200 cm−1in samples typically 100 μm thick. This paper reviews the current state of research, from the most successful synthetic strategies to produce polymeric photorefractive materials, to their emerging uses in applications. Two-beam coupling and four-wave mixing measurement techniques are presented and their importance in the characterization of the photorefractive properties of new materials is explained. The physics of the photorefractive effect in polymers is discussed with emphasis placed on the differences compared with the traditional inorganic photorefractive crystals. In particular, the orientational enhancement mechanism, which is believed to be responsible for the high performance of most of the low-glass-transition-temperature systems, is discussed in detail.
POLYCRYSTALLINE THIN FILM SOLAR CELLS:Present Status and Future Potential
Authors: Birkmire Robert W. , Eser Erten
Published: July 2002

▪ Abstract  Polycrystalline thin film solar cells on copper indium diselenide (CulnSe2) and its alloys and cadmium telluride (CdTe) appear to be the most promising candidates for large-scale application of photovoltaic energy conversion because they have shown laboratory-efficiences in excess of 15%. Heterojunction devices with n-type cadmium sulfide (CdS) films show very low minority carrier recombination at the absorber grain boundaries and at the metallurgical interface, which results in high quantum efficiences. Open circuit voltages of these devices are relatively low owing to the recombination in the space charge region in the absorber. Further improvements in efficiency can be achieved by reducing the recombination current, especially in devices based on CulnSe2and its alloys. Low-cost manufacturing of modules requires better resolution of a number of other technical issues. For modules based on CulnSe2and its alloys, the role of Na and higher deposition rates on device performance need to be better understood. In addition, replacing the chemical bath deposition method for CdS film deposition with an equally effective, but more environmentally acceptable process is needed. For modules based on CdTe, more fundamental understanding of the effect of chloride/oxygen treatment and the development of more reproducible and manufacturable CdTe contacting schemes are necessary.
SOFT LITHOGRAPHY
Authors: Xia Younan , Whitesides George M.
Published: July 2002

Abstract  Soft lithography represents a non-photolithographic strategy based on self-assembly and replica molding for carrying out micro- and nanofabrication. It provides a convenient, effective, and low-cost method for the formation and manufacturing of micro- and nanostructures. In soft lithography, an elastomeric stamp with patterned relief structures on its surface is used to generate patterns and structures with feature sizes ranging from 30 nm to 100 μm. Five techniques have been demonstrated: microcontact printing (μCP), replica molding (REM), microtransfer molding (μTM), micromolding in capillaries (MIMIC), and solvent-assisted micromolding (SAMIM). In this chapter we discuss the procedures for these techniques and their applications in micro- and nanofabrication, surface chemistry, materials science, optics, MEMS, and microelectronics.
HIGH-PRESSURE SYNTHESIS, CHARACTERIZATION, AND TUNING OF SOLID STATE MATERIALS
Authors: Badding J. V.
Published: July 2002

▪ Abstract  The synthesis, characterization, and tuning of solid state materials by means of high-pressure techniques is reviewed from the perspective of a solid state chemist. Because pressure can affect significant changes in reaction equilibria, it is a useful tool for the synthesis of novel and metastable materials. Several different examples ranging from the behavior of carbon under pressure to oxide materials and intermetallic compounds are presented to illustrate the breadth of opportunities in this area. Pressure allows precise tuning of a fundamental parameter, interatomic distance, which controls the electronic structure and virtually all the interatomic interactions that determine materials properties. With pressure tuning, properties can often be more rapidly and cleanly optimized than with chemical tuning, which necessitates the synthesis of a large number of different materials and can induce disorder, phase separation, and other undesirable effects. Pressure tuning is therefore a useful tool in the search for new solid state materials with enhanced properties such thermoelectric materials and intermetallic structural materials.
APPLICATIONS OF ULTRASOUND TO MATERIALS CHEMISTRY
Authors: Suslick Kenneth S. , Price Gareth J.
Published: July 2002

▪ Abstract  The chemical effects of ultrasound derive primarily from acoustic cavitation. Bubble collapse in liquids results in an enormous concentration of energy from the conversion of the kinetic energy of the liquid motion into heating of the contents of the bubble. The high local temperatures and pressures, combined with extraordinarily rapid cooling, provide a unique means for driving chemical reactions under extreme conditions. A diverse set of applications of ultrasound to enhance chemical reactivity has been explored with important uses in synthetic materials chemistry. For example, the sonochemical decomposition of volatile organometallic precursors in low-volatility solvents produces nanostructured materials in various forms with high catalytic activities. Nanostructured metals, alloys, oxides, carbides and sulfides, nanometer colloids, and nanostructured supported catalysts can all be prepared by this general route. Another important application of sonochemistry in materials chemistry has been the preparation of biomaterials, most notably protein microspheres. Such microspheres have a wide range of biomedical applications, including their use in echo contrast agents for sonography, magnetic resonance imaging, contrast enhancement, and oxygen or drug delivery. Other applications include the modification of polymers and polymer surfaces.
PANCREAS TRANSPLANTATION FOR DIABETES MELLITUS
Authors: Stratta, M.D Robert J. , Larsen, M.D Jennifer L. , Cushing, R.N., B.S.N Kathleen
Published: July 2002

▪ Abstract  Vascularized pancreas transplantation has assumed an increasing role in the treatment of diabetes mellitus. Through 1993, over 5500 pancreas transplants have been performed worldwide, with over 80% being combined pancreas-kidney transplants. Overall one-year patient survival exceeds 90% and graft survival (complete insulin independence) exceeds 70%. Although successful pancreas transplantation achieves euglycemia and complete insulin independence, this occurs at the expense of hyperinsulinemia and chronic immunosuppression. The net result of these changes on diabetic complications in the long term remains to be determined. In the short term, improvement in the quality of life and possible prevention of further morbidity associated with diabetes makes pancreas transplantation an important therapeutic option, particularly when combined with a kidney transplant, in appropriately selected diabetic patients.
FETAL SURGERY
Authors: Flake, M.D Alan W. , Harrison, M.D Michael R.
Published: July 2002

▪ Abstract  Fetal surgery, as defined for the purpose of this chapter, is the act of opening the gravid uterus, surgically correcting a fetal abnormality, and returning the fetus to the uterus for postoperative recovery and continued gestational development. By this definition, human fetal surgery has now been performed for more than a decade, primarily at a single center ( 1 ). Tremendous progress has been made in our understanding of the natural history and pathophysiology of fetal disease, in solving the technical challenges of fetal surgery, and in intra- and postoperative care and monitoring of the maternal-fetal unit. However, success and general application of fetal surgery continue to be limited by a number of unsolved and formidable problems. The most important of these is the control of preterm labor, which is the Achilles heel of fetal surgery. Preterm labor is to the infantile field of fetal surgery what rejection was to the field of transplantation. The discovery of effective tocolysis would be analogous to the development of effective immunosuppression and would allow fetal surgery to achieve its full potential. In addition, less invasive methods of operating on the fetus are emerging that will further reduce the maternal and fetal risk of this currently highly invasive treatment.
MANAGEMENT OF PATIENTS WITH INTERMEDIATE-THICKNESS MELANOMA
Authors: Urist, M.D Marshall M.
Published: July 2002

▪ Abstract  It is important to understand the management of patients with melanoma because of a rising incidence of this cancer in the United States. The most important prognostic factor is tumor thickness. Patients with early melanoma (thickness <1.0 mm) have an excellent prognosis and are effectively treated with narrow local excision (1-cm radius). Those with advanced melanomas (tumor thickness >4.0 mm) have a high risk of metastases and are treated with a wider local excision (2–3 cm). Controversies surrounding the management of patients with intermediate-thickness melanoma (thickness 1–4 mm) center on the issues of local excision and management of regional lymph nodes. Randomized trials have shown that a 2-cm radius of excision will minimize the risk for local recurrence. Although retrospective analyses have indicated a survival advantage for elective regional lymph node dissection, two randomized trials have not shown a benefit for the early removal of lymph nodes. Two more randomized trials are in progress. Techniques are now available to identify the sentinel lymph node, which will help to limit lymph node dissections to those patients with nodal metastases. Postoperative surveillance for recurrence is most effectively performed with a combination of patient self-examination and regular physician examinations rather than frequent X-rays and laboratory tests. Adjuvant therapy has not been proven effective for melanoma patients; however, many investigational trials are available.
Detection of Minimal Residual Disease: Relevance for Diagnosis and Treatment of Human Malignancies
Authors: Hirsch-Ginsberg Cheryl
Published: July 2002

Minimal residual disease (MRD) is the tumor burden that is present after a course of treatment that has resulted in clinical remission. For hematopoietic malignancies, techniques for detection of this minimal tumor burden are being used to monitor MRD. These involve methods that are capable of identifying very low numbers of neoplastic cells in an otherwise normal marrow or lymph node. Patients with demonstrable residual neoplastic cells tend to do worse than patients without detectable cells; however, results depend on the timing of the assay and whether the detectable neoplastic cells appear to be increasing in number with subsequent assays. For bone marrow transplantation, assays incorporating chimerism analyses, cytogenetics, and morphology are used to regulate therapy.
Gastric Lymphoma of Mucosa-Associated Lymphoid Tissue andHelicobacter pylori
Authors: Wotherspoon A. C.
Published: July 2002

Although the majority of primary gastric lymphomas are of high-grade non-Hodgkin's type, a significant number are low-grade B cell lymphomas. The recognition that the majority of the latter have characteristic clinicopathological features that are different from those of their nodal counterparts has led to the suggestion that these lymphomas arise specifically from within organized extranodal lymphoid tissue; this tissue resembles that seen constitutively in the intestine (mostly located in the terminal ileum as Peyer's patches) and is termed mucosa-associated lymphoid tissue (MALT). The paradox of this proposal is that there is no MALT in the gastric mucosa in normal individuals from which a primary lymphoma can arise. However, it has been shown that organized lymphoid tissue with all the features of MALT can be acquired in the gastric mucosa, and this is seen most frequently, but not exclusively, in association with infection by Helicobacter pylori H. pylori). Subsequent studies have confirmed a close association between H. pylori infection and gastric MALT lymphoma with the infection preceding the development of the lymphoma. In vitro studies have demonstrated that there is an immunologically based drive to tumor cell proliferation in low-grade gastric MALT lymphomas associated with the presence of H. pylori. Clinical studies have shown that, at least in early lesions, eradication of the organism can result in tumor regression in 60 to 92% of cases.
Management of Patients with Hereditary Hypercoagulable Disorders
Authors: Kearon C. , Crowther M. , Hirsh J.
Published: July 2002

▪ Abstract  The inherited hypercoagulable states can be divided into those that are common and associated with a modest risk of thrombosis (i.e. factor V Leiden and G20210A prothrombin gene) and those that are uncommon but asssociated with a high risk of thrombosis. There is no convincing evidence that, independent of other clinical factors, the presence of factor V Leiden or the prothrombin gene mutation should influence the use of primary prophylaxis or the duration of anticoagulant therapy following an episode of thrombosis. Indrect evidence sugests that the presence of antithrombin, protein C deficiency, or protein S deficiency justifies avoiding additional risk factors for thrombosis, such as estrogen therapy, and justifies use of more aggressive primary prophylaxis when additional risk factors cannot readily be avoided (e.g. pregnancy). The presence of one of these three abnormalities also favors more prolonged anticoagulant therapy following venous thrombosis. However, their presence or absence appears to have less influence on the risk of recurrent venous thromboembolism than whether thrombosis was provoked by a major reversible risk factor, such as surgery.
Kidney Transplantation from Living Unrelated Donors
Authors: Cecka J. Michael
Published: July 2002

Kidney transplant candidates increasingly are looking to their relatives, spouses, and even friends for a better chance at transplantation. The wait for a cadaver kidney might be 2–5 years. Although kidneys from well-matched family members have been transplanted with excellent results for many years, accepting living donors who are genetically unrelated to the patient has not been encouraged until recently. Results show that, among 1700 patients who received kidney transplants from living unrelated donors in the United States from 1995 through 1998, the one- and projected ten-year graft survival rates were 92% and 67%, respectively. These results are superior to the 87% and 50% rates for more than 26,000 cadaver kidney transplants during the same period. Risks to the donor are low (<0.005% mortality and <0.3% serious complications) but not absent. Thus, motivated spouses, friends, and adopted or stepfamily members can play an important role in the rehabilitation of patients who need a kidney transplant.
Thrombotic Thrombocytopenic Purpura: The Systemic Clumping “Plague”
Authors: Moake Joel L.
Published: July 2002

▪ Abstract  In thrombotic thrombocytopenic purpura (TTP), a multimeric form of von Willebrand factor (vWf) that is larger than ordinarily found in the plasma causes systemic platelet aggregation under the high-shear conditions of the microcirculation. A divalent cation–activated, vWf-cleaving metalloprotease that metabolizes large vWf multimers to smaller forms in normal plasma is severely reduced or absent in most patients with TTP. The vWf-cleaving metalloprotease either is not produced or is defective in children with chronic relapsing TTP. When the enzyme is provided by the infusion of normal plasma, these patients remain free of TTP symptoms for about three weeks. An IgG autoantibody to the vWf-cleaving metalloprotease is found transiently in many adult patients with acute idiopathic, recurrent, and ticlopidine/clopidogrel-associated TTP. These patients require plasma exchange, i.e., concurrent replacement of the inhibited vWf-cleaving metalloprotease by plasma infusion and plasmapheresis. The vWf-cleaving metalloprotease is present in fresh-frozen plasma, in cryoprecipitate-depleted plasma (cryosupernatant), and in plasma that has been treated with solvent and detergent. The pathophysiology of platelet aggregation in bone marrow transplantation/chemotherapy–associated thrombotic microangiopathy, and in the hemolytic-uremic syndrome, is not established. In neither condition is there a severe decrease in plasma vWf–cleaving metalloprotease activity.
LESSONS FROM A COOPERATIVE, BACTERIAL-ANIMAL ASSOCIATION: The Vibrio fischeri–Euprymna scolopes Light Organ Symbiosis
Authors: Ruby Edward G.
Published: July 2002

Although the study of microbe-host interactions has been traditionally dominated by an interest in pathogenic associations, there is an increasing awareness of the importance of cooperative symbiotic interactions in the biology of many bacteria and their animal and plant hosts. This review examines a model system for the study of such symbioses, the light organ association between the bobtail squid Euprymna scolopes and the marine luminous bacterium Vibrio fischeri. Specifically, the initiation, establishment, and persistence of the benign bacterial infection of the juvenile host light organ are described, as are efforts to understand the mechanisms underlying this specific colonization program. Using molecular genetic techniques, mutant strains of V. fischeri have been constructed that are defective at specific stages of the development of the association. Some of the lessons that these mutants have begun to teach us about the complex and long-term nature of this cooperative venture are summarized.
INTERACTION OF ANTIGENS AND ANTIBODIES AT MUCOSAL SURFACES
Authors: Lamm Michael E.
Published: July 2002

▪ Abstract  Infections often involve the mucosal surfaces of the body, which form a boundary with the outside world. This review focuses on immunoglobulin A (IgA) antibodies because IgA is the principal mucosal antibody class. IgA is synthesized by local plasma cells and has a specific polymeric immunoglobulin receptor-mediated transport mechanism for entry into the secretions. By serving as an external barrier capable of inhibiting attachment of microbes to the luminal surface of the mucosal epithelial lining, IgA antibodies form the first line of immune defense. In addition to this traditional mode of extracellular antibody function, recent evidence suggests that IgA antibodies can also function in a nontraditional fashion by neutralizing viruses intracellularly, if a virus is infecting an epithelial cell through which specific IgA antibody is passing on its way to the secretions. IgA antibodies are also envisaged as providing an internal mucosal barrier beneath the mucosal lining. Antigens intercepted by IgA antibodies here can potentially be ferried through the epithelium and thereby excreted. In addition to the polymeric immunoglobulin receptor on mucosal epithelial cells, IgA antibodies can bind to receptors on a variety of leukocytes and have been shown, in some experimental systems, to be capable of activating the alternative complement pathway, making IgA antibodies potential participants in inflammatory reactions. Although the relationship of IgA antibodies to inflammation is not entirely clear, the bias presented is that IgA is basically noninflammatory, perhaps even anti-inflammatory. According to this view, the major role of the Fc portion of IgA antibodies is to transport IgA across mucosal epithelial cells and not, as in the case of the other classes of antibody, to activate secondary phenomena of the kind that contribute to inflammation. Because of IgA's key role as an initial barrier to infection, much current research in mucosal immunology is directed toward developing new vectors and adjuvants that can provide improved approaches to mucosal vaccines. Finally, because of advances in monoclonal antibody technology, topical application of antibodies to mucosal surfaces has significant potential for preventing and treating infections.
Emotion Circuits in the Brain
Authors: LeDoux Joseph E.
Published: July 2002

The field of neuroscience has, after a long period of looking the other way, again embraced emotion as an important research area. Much of the progress has come from studies of fear, and especially fear conditioning. This work has pinpointed the amygdala as an important component of the system involved in the acquisition, storage, and expression of fear memory and has elucidated in detail how stimuli enter, travel through, and exit the amygdala. Some progress has also been made in understanding the cellular and molecular mechanisms that underlie fear conditioning, and recent studies have also shown that the findings from experimental animals apply to the human brain. It is important to remember why this work on emotion succeeded where past efforts failed. It focused on a psychologically well-defined aspect of emotion, avoided vague and poorly defined concepts such as “affect,” “hedonic tone,” or “emotional feelings,” and used a simple and straightforward experimental approach. With so much research being done in this area today, it is important that the mistakes of the past not be made again. It is also time to expand from this foundation into broader aspects of mind and behavior
Viktor Hamburger and Rita Levi-Montalcini: The Path to the Discovery of Nerve Growth Factor
Authors: Cowan W. Maxwell
Published: July 2002

▪ Abstract  The announcement in October 1986 that the Nobel Prize for physiology or medicine was to be awarded to Rita Levi-Montalcini and Stanley Cohen for the discoveries of NGF and EGF, respectively, caused many to wonder why Viktor Hamburger (in whose laboratory the initial work was done) had not been included in the award. Now that the dust has settled, the time seems opportune to reconsider the antecedent studies on the relation of the developing nervous system to the peripheral structures it innervates. The studies undertaken primarily to investigate this issue culminated in the late 1950s in the discovery that certain tissues produce a nerve growth–promoting factor that is essential for the survival and maintenance of spinal (sensory) ganglion cells and sympathetic neurons. In this review, the many contributions that Viktor and Rita made to this problem, both independently and jointly, are reexamined by considering chronologically each of the relevant research publications together with some of the retrospective memoirs they have published in the years since the discovery of NGF was first reported.

This review is dedicated to Viktor Hamburger on the occasion of his 100th birthday on July 9, 2000, and to Rita Levi-Montalcini to mark her 91st birthday on April 22, 2000, with admiration and affection.