Showing papers by "University of Tennessee published in 1994"

Fusion of a Kinase Gene, ALK, to a Nucleolar Protein Gene, NPM, in Non-Hodgkin's Lymphoma

Abstract: The 2;5 chromosomal translocation occurs in most anaplastic large-cell non-Hodgkin's lymphomas arising from activated T lymphocytes. This rearrangement was shown to fuse the NPM nucleolar phosphoprotein gene on chromosome 5q35 to a previously unidentified protein tyrosine kinase gene, ALK, on chromosome 2p23. In the predicted hybrid protein, the amino terminus of nucleophosmin (NPM) is linked to the catalytic domain of anaplastic lymphoma kinase (ALK). Expressed in the small intestine, testis, and brain but not in normal lymphoid cells, ALK shows greatest sequence similarity to the insulin receptor subfamily of kinases. Unscheduled expression of the truncated ALK may contribute to malignant transformation in these lymphomas.

What we have learned about Mars from SNC meteorites

Abstract: The SNC meteorites are thought to be igneous martian rocks, based on their young crystallization ages and a close match between the composition of gases implanted in them during shock and the atmosphere of Mars. A related meteorite, ALH84001, may be older and thus may represent ancient martian crust. These petrologically diverse basalts and ultramafic rocks are mostly cumulates, but their parent magmas share geochemical and radiogenic isotopic characteristics that suggest they may have formed by remelting the same mantle source region at different times. Information and inferences about martian geology drawn from these samples include the following: Planetary differentiation occured early at approximately 4.5 GA, probably concurrently with accretion. The martian mantle contains different abundances of moderately volatile and siderophile elements and is more Fe-rich than that of the Earth, which has implications for its mineralogy, density, and origin. The estimated core composition has a S abundance near the threshold value for inner core solidification. The former presence of a core dynamo may be suggested by remanent magnetization in Shergottite-Nakhlite-Chassignite (SNC) meteorites, although these rocks may have been magnetized during shock. The mineralogy of martian surface units, inferred from reflectance spectra, matches that of basaltic shergottites, but SNC lithologies thought to have crystallized in the subsurface are not presently recognized. The rheological properties of martian magmas are more accurately derived form these metorites than from observations of martian flow morphology, although the sampled range of magma compositions islimited. Estimates of planetary water abundance and the amount of outgassed water based on these meteorites are contridictory but overlap estimates based on geological observations and atmospheric measurements. Stable isotope measurements indicate that the martian hydrosphere experienced only limited exchange with the lithosphere, but it is in isotopic equilibrium with the atmosphere and has been since 1.3 Ga. The isotopically heavy atmosphere/hydrosphere composition deduced from these rocks reflects a loss process more severe than current atmospheric evolution models, and the occurence of carbonates in SNC meteorites suggest that they, rather than scapolite or hydrous carbonates, are the major crustal sink for CO2. Weathering products in SNC meteorites support the idea of limited alteration of the lithosphere by small volumes of saline, CO2-bearing water. Atmospheric composition and evolution are further constrained by noble gases in these meteorites, although Xe and Kr isotopes suggest different origins for the atmosphere. Planetary ejection of these rocks has promoted an advance in the understanding of impact physics, which has been accomplished by a model involving spallation during large cratering events. Ejection of all the SNC meteorites (except ALH84001) in one or two events may provide a plausible solution to most constraints imposed by chronology, geochemistry, and cosmic ray exposure, although problems remain with this scenario; ALH84001 may represent older martian crust sampled during a separate impact.

A Markov chain model for statistical software testing

Abstract: Statistical testing of software establishes a basis for statistical inference about a software system's expected field quality. This paper describes a method for statistical testing based on a Markov chain model of software usage. The significance of the Markov chain is twofold. First, it allows test input sequences to be generated from multiple probability distributions, making it more general than many existing techniques. Analytical results associated with Markov chains facilitate informative analysis of the sequences before they are generated, indicating how the test is likely to unfold. Second, the test input sequences generated from the chain and applied to the software are themselves a stochastic model and are used to create a second Markov chain to encapsulate the history of the test, including any observed failure information. The influence of the failures is assessed through analytical computations on this chain. We also derive a stopping criterion for the testing process based on a comparison of the sequence generating properties of the two chains. >

Expert system, fuzzy logic, and neural network applications in power electronics and motion control

Abstract: Artificial intelligence (AI) tools, such as expert systems, fuzzy logic, and neural networks are expected to usher a new era in power electronics and motion control in the coming decades. Although these technologies have advanced significantly and have found wide applications, they have hardly touched the power electronics and machine drives area. The paper describes these AI tools and their application in the area of power electronics and motion control. The body of the paper is subdivided into three sections which describe, respectively, the principles and applications of expert systems, fuzzy logic, and neural networks. The theoretical portion of each topic is of direct relevance to the application of power electronics. The example applications in the paper are taken from the published literature. >

Convergence of the Cahn-Hilliard equation to the Hele-Shaw model

Abstract: We prove that level surfaces of solutions to the Cahn-Hilliard equation tend to solutions of the Hele-Shaw problem under the assumption that classical solutions of the latter exist. The method is based on a new matched asymptotic expansion for solutions, a spectral analysis for linearizd operators, and an estimate for the difference between the true solutions and certain approximate ones.

Students' Perceptions of EAP Writing Instruction and Writing Needs Across the Disciplines

Abstract: As English for academic purposes (EAP) writing instructors and writing curriculum planners, we need to know the degree to which ESL writing courses have been successful in gauging and providing for ESL students' writing needs across the university curriculum However, making this determination is difficult because many academic writing requirements may be implicit in the curriculum of the disciplinary course and thus not amenable to ready description by the outsider Furthermore, we also need to know how much carryover from ESL writing courses occurs with ESL students—that is, what elements of their ESL writing instruction have they found useful and available to them as students in content courses? This article reports on a survey of former ESL students now in university-level content courses that is designed to investigate students' perceptions of the relationship between the writing instruction the students received in ESL writing classes and the actual writing tasks they found in courses across the disciplines The results of the survey include indications of which writing skills taught in ESL writing courses students found most useful in dealing with the writing demands of other content courses In their answers to open-ended survey questions, ESL students also described their perceptions of their ongoing writing needs beyond the ESL writing curriculum

Candidate gene associated with a mutation causing recessive polycystic kidney disease in mice

Abstract: A line of transgenic mice was generated that contains an insertional mutation causing a phenotype similar to human autosomal recessive polycystic kidney disease. Homozygotes displayed a complex phenotype that included bilateral polycystic kidneys and an unusual liver lesion. The mutant locus was cloned and characterized through use of the transgene as a molecular marker. Additionally, a candidate polycystic kidney disease (PKD) gene was identified whose structure and expression are directly associated with the mutant locus. A complementary DNA derived from this gene predicted a peptide containing a motif that was originally identified in several genes involved in cell cycle control.

Consumer recycling goals and their effect on decisions to recycle: A means-end chain analysis

Abstract: Means-end chain theory and the laddering methodology were used to derive the goals relevant to consumers for recycling, as well as the interrelations among goals. The importance of the goals and their hierarchical structure were also tested, and their effects on attitudes, subjective norms, and past behavior determined. Data were collected on 133 consumers in a moderate-size metropolitan community by use of a random digit dialing procedure. The overall framework emerging from the analyses is one where concrete goals lead to more abstract goals, and attitudes and past behavior intervene between goals and intentions in decision making. Nineteen total goals were uncovered, with 15 ultimately found to be salient. The topmost goals in the hierarchy were “promote health/avoid sickness,” “achieve life-sustaining ends,” and “provide for future generations.” The key lower-order goals—“avoid filling up landfills,” “reduce waste,” “reuse materials,” and “save the environment”—work through such intermediary goals as “reduce messy trash,” “curtail pollution,” “save resources,” and “save the planet.” Two important terminal goals that were also at intermediate levels in the hierarchy were “save/earn money” and “it's the right thing to do.” © 1994 John Wiley & Sons, Inc.

The PVM concurrent computing system: evolution, experiences, and trends

Abstract: The PVM system, a software framework for heterogeneous concurrent computing in networked environments, has evolved in the past several years into a viable technology for distributed and parallel processing in a variety of disciplines. PVM supports a straightforward but functionally complete message passing model, and is capable of harnessing the combined resources of typically heterogeneous networked computing platforms to deliver high levels of performance and functionality. In this paper, we describe the architecture of PVM system, and discuss its computing model, the programming interface it supports, auxiliary facilities for process groups and MPP support, and some of the internal implementation techniques employed. Performance issues, dealing primarily with communication overheads, are analyzed, and recent findings as well as experimental enhancements are presented. In order to demonstrate the viability of PVM for large scale scientific supercomputing, the paper includes representative case studies in materials science, environmental science, and climate modeling. We conclude with a discussion of related projects and future directions, and comment on near and long-term potential for network computing with the PVM system.

Changes in Ester-Linked Phospholipid Fatty Acid Profiles of Subsurface Bacteria during Starvation and Desiccation in a Porous Medium

Abstract: Ester-linked phospholipid fatty acid (PLFA) profiles of a Pseudomonas aureofaciens strain and an Arthrobacter protophormiae strain, each isolated from a subsurface sediment, were quantified in a starvation experiment in a silica sand porous medium under moist and dry conditions. Washed cells were added to sand microcosms and maintained under saturated conditions or subjected to desiccation by slow drying over a period of 16 days to final water potentials of approximately - 7.5 MPa for the P. aureofaciens and - 15 MPa for the A. protophormiae. In a third treatment, cells were added to saturated microcosms along with organic nutrients and maintained under saturated conditions. The numbers of culturable cells of both bacterial strains declined to below detection level within 16 days in both the moist and dried nutrient-deprived conditions, while direct counts and total PLFAs remained relatively constant. Both strains of bacteria maintained culturability in the nutrient-amended microcosms. The dried P. aureofaciens cells showed changes in PLFA profiles that are typically associated with stressed gram-negative cells, i.e., increased ratios of saturated to unsaturated fatty acids, increased ratios of trans- to cis-monoenoic fatty acids, and increased ratios of cyclopropyl fatty acids to their monoenoic precursors. P. aureofaciens starved under moist conditions showed few changes in PLFA profiles during the 16-day incubation, whereas cells incubated in the presence of nutrients showed decreases in the ratios of both saturated fatty acids to unsaturated fatty acids and cyclopropyl fatty acids to their monoenoic precursors. The PLFA profiles of A. protophormiae changed very little in response to either nutrient deprivation or desiccation. Diglyceride fatty acids, which have been proposed to be indicators of dead or lysed cells, remained relatively constant throughout the experiment. Only the A. protophormiae desiccated for 16 days showed an increase in the ratio of diglyceride fatty acids to PLFAs. The results of this laboratory experiment can be useful for interpreting PLFA profiles of subsurface communities of microorganisms for the purpose of determining their physiological status.

Nuclear shell structure at particle drip lines

Abstract: The shell structure of exotic nuclei near proton and neutron drip lines is discussed in terms of the self-consistent mean-field theory. It is demonstrated that when approaching the neutron drip line, the neutron density becomes very diffused and the single-particle spectrum shows similarities to that of the harmonic oscillator with spin-orbit term. Interaction between bound orbitals and continuum is shown to result in quenching of shell effects in light and medium systems.

Optical biosensor for environmental on-line monitoring of naphthalene and salicylate bioavailability with an immobilized bioluminescent catabolic reporter bacterium.

Abstract: An optical whole-cell biosensor based on a genetically engineered bioluminescent catabolic reporter bacterium was developed for continuous on-line monitoring of naphthalene and salicylate bioavailability and microbial catabolic activity potential in waste streams. The bioluminescent reporter bacterium, Pseudomonas fluorescens HK44, carries a transcriptional nahG-luxCDABE fusion for naphthalene and salicylate catabolism. Exposure to either compound resulted in inducible bioluminescence. The reporter culture was immobilized onto the surface of an optical light guide by using strontium alginate. This biosensor probe was then inserted into a measurement cell which simultaneously received the waste stream solution and a maintenance medium. Exposure under defined conditions to both naphthalene and salicylate resulted in a rapid increase in bioluminescence. The magnitude of the response and the response time were concentration dependent. Good reproducibility of the response was observed during repetitive perturbations with either naphthalene or salicylate. Exposure to other compounds, such as glucose and complex nutrient medium or toluene, resulted in either minor bioluminescence increases after significantly longer response times compared with naphthalene or no response, respectively. The environmental utility of the biosensor was tested by using real pollutant mixtures. A specific bioluminescence response was obtained after exposure to either an aqueous solution saturated with JP-4 jet fuel or an aqueous leachate from a manufactured-gas plant soil, since naphthalene was present in both pollutant mixtures.

Optimum band gap of a thermoelectric material.

Abstract: Transport properties of direct-gap semiconductors are calculated in order to find the best thermoelectrics Previous calculations on semiconductors with indirect band gaps found that the best thermoelectrics had gaps equal to ${\mathit{nk}}_{\mathit{B}}$T, where n=6-10 and T is the operating temperature of the thermoelectric device Here we report similar calculations on direct-gap materials We find that the optimum gap is always greater than 6${\mathit{k}}_{\mathit{B}}$T, but can be much larger depending on the specific mechanism of electron scattering

Heat capacity measurement by modulated DSC at constant temperature

Abstract: The mathematical equations for step-wise measurement of heat capacity (Cp) by modulated differential scanning calorimetry (MDSC) are discussed for the conditions of negligible temperature gradients within sample and reference. Using a commercial MDSC, applications are evaluated and the limits explored. This new technique permits the determination ofCp by keeping the sample continually close to equilibrium, a condition conventional DSC is unable to meet. Heat capacity is measured at ‘practically isothermal condition’ (often changing not more than ±1 K). The method provides data with good precision. The effects of sample mass, amplitude and frequency of temperature modulation were studied and methods for optimizing the instrument are proposed. The correction for the differences in sample and reference heating rates, needed for high-precision data by standard DSC, do not apply for this method.

The dynamics of long-term business-to-business exchange relationships

Abstract: A framework for business-to-business interaction is proposed that integrates approaches to bargaining from social psychology and economics to provide a conceptual paradigm emphasizing long-term exchange relationships rather than individual transactions. The authors propose a classification of negotiation behavior along two continuous dimensions and examine the mechanics of the dyadic negotiation process that translate negotiation behavior into long-term relationships. They suggest that exchange relationships are formed by achieving mutually beneficial outcomes from a series of exchange transactions and that there is a bi-directional link between negotiation behavior and exchange relationships mediated by negotiation outcomes. The framework also explores the determinants of negotiation behavior in dyadic negotiations between businesses in terms of organizational, individual, and “other party” influences. Propositions are developed, using both role theory and economic bargaining theory, to support the overall framework. Finally, the classification of negotiation behavior is revisited to examine the evolution of exchange relationships over time.

Mixture-Model Cluster Analysis Using Model Selection Criteria and a New Informational Measure of Complexity

Abstract: Analysis of clusters by means of mixture distribution, called mixture-model cluster analysis, has been one of the most difficult problems in statistics. But theoretical work, coupled with the development of new computational tools in the past ten years, has been made it possible to overcome some of the intractable technical and numerical issues that have limited the widespread applicability of mixture-model cluster analysis to complex real-word problems. The development of new objective analysis techniques had to wait the emergence of information-based model selection procedure to overcome difficulties with cinventional techniques within the context of the mixture-model cluster analysis. See, e.g., Bozdogan (1992), Windham and Cutler (1993) (in this volume)

Interlocking intramedullary nailing of femoral-shaft fractures in adolescents: preliminary results and complications.

Abstract: Thirty-one femoral-shaft fractures in 30 patients were treated with interlocking intramedullary nails. The 19 boys and 11 girls ranged in age from 10 to 15 years (average age 12 + 3 years) at the time of injury. All fractures united, and the average leg-length discrepancy (comparing the injured to the uninjured extremity) was 0.51 cm. Two patients had overgrowth of > 2.5 cm; none had angular or rotational malunions. One patient developed asymptomatic segmental avascular necrosis of the femoral head, which was not seen on radiographs until 15 months after injury. All nails were removed at an average of 14 months after injury; no refracture or femoral neck fracture has since occurred. Intramedullary nailing is a reasonable alternative for the treatment of isolated femoral-shaft fractures in older adolescents and in younger adolescents with multiple trauma.

Neural network based estimation of feedback signals for a vector controlled induction motor drive

Abstract: Neural networks are showing promise for application in power electronics and motion control systems. So far, they have been applied for a few cases, mainly in the control of converters and drives, but their application in estimation is practically new. The purpose of this paper is to demonstrate that such a technology can be applied for estimation of feedback signals in an induction motor drive with some distinct advantages when compared to DSP based implementation. A feedforward neural network receives the machine terminal signals at the input and calculates flux, torque, and unit vectors (cos /spl theta//sub e/ and sin /spl theta//sub e/) at the output which are then used in the control of a direct vector-controlled drive system. The three-layer network has been trained extensively by Neural Works Professional II/Plus program to emulate the DSP-based computational characteristics. The performance of the estimator is good and is comparable to that of DSP-based estimation. The system has been operated in the wide torque and speed regions independently with a DSP-based estimator and a neural network-based estimator, and are shown to have comparable performance. The neural network estimator has the advantages of faster execution speed, harmonic ripple immunity, and fault tolerance characteristics compared to DSP-based estimator. >

Evidence of an oxidative challenge in the Alzheimer's brain

Abstract: Alzheimer's disease may arise from or produce oxidative damage in the brain. To assess the responses of the Alzheimer's brain to possible oxidative challenges, we assayed for glutathione, glucose-6-phosphate dehydrogenase, catalase and superoxide dismutase in twelve regions of Alzheimer's disease and aged control brains. In addition, we determined levels of malondialdehyde to evaluate lipid peroxidation in these brain regions. Most brain regions showed evidence of a response to an oxidative challenge, but the cellular response to this challenge differed among brain regions. These data suggest that the entire Alzheimer's brain may be subject to an oxidative challenge, but that some brain areas may be more vulnerable than others to the consequent neural damage that characterizes the disease.

Enzyme replacement in a canine model of Hurler syndrome

Abstract: The Hurler syndrome (alpha-L-iduronidase deficiency disease) is a severe lysosomal storage disorder that is potentially amenable to enzyme-replacement therapy. Availability of a canine model of the disease and a sufficient supply of corrective enzyme have permitted a therapeutic trial lasting 3 mo. Recombinant human alpha-L-iduronidase, purified to apparent homogeneity from secretions of a stably transfected Chinese hamster ovary cell line, was administered i.v. to homozygous affected animals in doses of approximately 1 mg. The enzyme rapidly disappeared from the circulation in a biphasic manner, with t1/2 of 0.9 and 19 min, respectively, and was taken up primarily by the liver. Biopsy of the liver before and after a very short trial (seven doses administered over 12 days) showed remarkable resolution of lysosomal storage in both hepatocytes and Kupffer cells. After weekly administration of enzyme to three affected animals over a period of 3 mo, the level of enzyme was about normal in liver and spleen, lower but significant in kidney and lung, and barely detectable (0-5% of normal) in brain, heart valves, myocardium, cartilage, and cornea. Light and electron microscopic examination of numerous tissues showed normalization of lysosomal storage in liver, spleen, and kidney glomeruli, but there was no improvement in brain, heart valves, or cornea. Even though the treated dogs developed complement-activating antibodies against alpha-L-iduronidase, clinical symptoms could be prevented by slow infusion of enzyme and premedication.

E-talk: Attitudes and motivation in computer-assisted classroom discussion

Abstract: This paper is the description of an experiment in E-talk, computer-assisted classroom discussion, undertaken at a large southwestern university with a class of intermediate French students. We describe the research design and the results as they relate to the students' attitudes and motivation. The research seems to indicate that there are important benefits to using a local area network (LAN) as a means of encouraging discussion amongst students.

CD4+CD8- T cells are the effector cells in disease pathogenesis in the scurfy (sf) mouse.

Abstract: Mice hemizygous for the X-linked mutation, scurfy (sf), exhibit a fatal lymphoreticular disease that is mediated by T lymphocytes. To evaluate the respective roles of CD4 or CD8 single positive T cells in scurfy disease, neonates were treated with mAbs directed against the CD4 or CD8 molecules. Whereas mice treated with an anti-CD8 Ab developed lesions and succumbed to disease at the same time (17 days) as their untreated scurfy littermates, mice treated with an anti-CD4 Ab lived up to 11 wk before developing scurfy disease. To insure a more complete elimination of the T cell subsets, the scurfy mutation was bred onto beta 2-microglobulin (beta 2m)-deficient (CD8-less) and CD4-deficient transgenic mouse lines. Whereas there was little moderation of disease in beta 2m-deficient scurfy mice, CD4-deficient scurfy mice had markedly decreased scurfy lesions and a prolonged life span, similar to that of anti-CD4-treated sf/Y mice. Additionally, scurfy disease was transplanted into H-2-compatible nude mice through the adoptive transfer of CD4+CD8- T cells, but not CD4-CD8+ T cells. Flow-cytometric analysis revealed that sf/Y mice have an increased percentage of activated CD4+ T cells in their lymph nodes. In addition, there is an increase in the in vitro production of cytokines in the cultured splenocytes of CD8-less, but not CD4-less, scurfy mice. These data suggest that CD4+ T cells are critical mediators of disease in the scurfy mouse.

Pumma: Parallel universal matrix multiplication algorithms on distributed memory concurrent computers

Abstract: This paper describes the Parallel Universal Matrix Multiplication Algorithms (PUMMA) on distributed memory concurrent computers. The PUMMA package includes not only the non-transposed matrix multiplication routine C = A{center_dot}B, but also transposed multiplication routines C = A{sup T}{center_dot}B, C = A{center_dot}B{sup T}, and C = A{sup T}{center_dot}B{sup T}, for a block scattered data distribution. The routines perform efficiently for a wide range of processor configurations and block sizes. The PUMMA together provide the same functionality as the Level 3 BLAS routine xGEMM. Details of the parallel implementation of the routines are given, and results are presented for runs on the Intel Touchstone Delta computer.