Showing papers by "University of Kansas published in 1991"

FtsZ ring structure associated with division in Escherichia coli.

Abstract: Genes for cell division have been identified in Escherichia coli by the isolation of conditional lethal mutations that block cell division, but do not affect DNA replication or segregation. Of these genes, ftsZ is of great interest as it acts earliest in the division pathway, is essential, its level dictates the frequency of division, and it is thought to be the target of two cell-division inhibitors, SulA, produced in response to DNA damage, and MinCD, which prevents division at old sites. Here we have used immunoelectronmicroscopy to localize the FtsZ protein to the division site. The results suggest that FtsZ self-assembles into a ring structure at the future division site and may function as a cytoskeletal element. The formation of this ring may be the point at which division is regulated.

Organizational fit and acquisition performance: Effects of post-acquisition integration

Abstract: Based on 173 acquisitions in the U.S. manufacturing industry, this study examines the impact of organizational differences between acquiring and acquired firms on post-acquisition performance. The findings indicate that differences in top management styles have a negative impact on performance in acquisitions characterized by both high and low levels of post-acquisition integration. However, no such relationship was observed between differences in the reward and evaluation systems and post-acquisition performance in either the high or low integration subgroups. Implications of the findings, along with directions for future research, have been discussed in the concluding section of this paper.

Derivatives of cyclodextrins exhibiting enhanced aqueous solubility and the use thereof

Abstract: Sulfoalkyl ether cyclodextrin derivatives and their use as solubilizing agents for water insoluble drugs for oral, intranasal, or parenteral administration are disclosed.

Social validity assessments: is current practice state of the art?

Abstract: The use of evaluative feedback from consumers to guide program planning and evaluation is often referred to as the assessment of social validity. Differing views of its role and value in applied behavior analysis have emerged, and increasingly stereotyped assessments of social validity are becoming commonplace. This paper argues that current applications of social validity assessments are straying from the point originally proposed for them. Thus, several suggestions for improving current social validity assessment are proposed, including (a) expanding the definition of consumers to acknowledge the variety of community members able and likely to affect a program's survival, (b) increasing the psychometric rigor of social validity assessments, (c) extending assessment to heretofore underrepresented populations, (d) implementing widespread application of well-designed social validity assessments, (e) increasing meaningful consumer involvement in the planning and evaluation of behavioral programs, and (f) educating consumers to make better informed programming decisions.

Design and in vitro studies of a needle-type glucose sensor for subcutaneous monitoring.

Abstract: A new miniaturized glucose oxidase based needle-type glucose microsensor has been developed for subcutaneous glucose monitoring. The sensor is equivalent in shape and size to a 26-guage needle (0.45-mm o.d.) and can be implanted with ease without any incision. The novel configuration greatly facilitates the deposition of enzyme and polymer films so that sensors with characteristics suitable for in vivo use (upper limit of linear range greater than 15 mM, response time less than 5 min, and sensitivity yielding a 5:1 signal-to-background ratio at normal basal glucose levels) can be prepared in high yield (greater than 60%). The sensor response is largely independent of oxygen tension in the normal physiological range. It also exhibits good selectivity against common interferences except for the exogenous drug acetaminophen.

Implantable glucose sensor

Abstract: Implantable enzymatic sensors (25, 43, 44) for biochemicals such as glucose are provided having an ideal size and geometry for optional long term implantation and linear responses over the concentration ranges of interest. The sensors (25, 43, 44) include an elongated body (10, 26, 46) supporting an indicating electrode section having an appropriate enzyme immobilized thereon to present an enzymatic indicating surface (21, 33, 54). A permeable synthetic polymer membrane (24, 42, 56) is applied over the sensor body (10, 26, 46) to protect the enzyme and regulate diffusion of analyte therethrough, to ensure linearity of sensor response. The sensors (25, 43) are of flexible design and can be implanted using a catheter. Alternately, the sensor (44) includes an internal indicating electrode body (46) housed within an apertured, hollow needle (48). A holder (66) affixed to the needle (48) allows for easy manipulation and implantation of the sensor (44).

The positive social and self concept consequences of sports team identification.

Abstract: As a result of increased geographic mobility, industrialization, and the like, traditional social and community ties have declined. Conversely, sports spectatorship has continued to flourish. We ar...

Empathic joy and the empathy-altruism hypothesis.

Abstract: Three experiments tested whether empathy evokes egoistic motivation to share vicariously in the victim's joy at improvement (the empathic-joy hypothesis) instead of altruistic motivation to increase the victim's welfare (the empathy-altruism hypothesis). In Experiment 1, Ss induced to feel either low or high empathy for a young woman in need were given a chance to help her. Some believed that if they helped they would receive feedback about her improvement; others did not. In Experiments 2 and 3, Ss induced to feel either low or high empathy were given a choice of getting update information about a needy person's condition. Before choosing, they were told the likelihood of the person's condition having improved--and of their experiencing empathic joy--was 20%, was 50%, or was 80%. Results of none of the experiments patterned as predicted by the empathic-joy hypothesis; instead, results of each were consistent with the empathy-altruism hypothesis.

A Comparison of the J -lntegral and CTOD Parameters for Short Crack Specimen Testing

Abstract: This study investigates the applicability of the J-integral test procedure to test short crack specimens in the temperature region below the initiation of ductile tearing where J 1 c cannot be measured. The current J-integral test procedure is restricted to determining the initiation of ductile tearing and requires that no specimen demonstrates brittle cleavage fracture. The J 1 c test specimen is also limited to crack-depth to specimen-width ratios (a/W) between 0.50 and 0.75. In contrast, the crack tip opening displacement (CTOD) test procedure can be used for testing throughout the entire temperature-toughness transition region from brittle to fully ductile behavior. Also, extensive research is being conducted to extend the CTOD test procedure to the testing of short crack specimens (alW ratios of approximately 0.15). The CTOD and J-integral fracture parameters are compared both analytically and experimentally using square (cross-section) three-point bend specimens of A36 steel with a/W ratios of 0.50 (deep crack) and 0.15 (short crack). Three-dimensional elastic-plastic finite element analyses are conducted on both the deep crack and the short crack specimens. The measured J-integral and CTOD results are compared at various levels of linear-elastic and elastic-plastic behavior. Experimental testing is conducted throughout the lower shelf and lower transition regions where stable crack growth does not occur. Very good agreement exists between the analytical and experimental results for both the short crack and deep crack specimens. Results of this study show that both the J-integral and the CTOD fracture parameters work well for testing in the lower shelf and lower transition regions where stable crack growth does not occur. A linear relationship is shown to exist between J-integral and CTOD throughout these regions for both the short and the deep crack specimens. These observations support the consideration to extend the J-integral test procedure into the temperature region of brittle fracture rather than limiting it to J 1 c at the initiation of ductile tearing. Also, analyzing short crack three-point bend specimen (a/W < 0.15) records using the load versus load-line displacement (LLD) record has great potential as an experimental technique. The problems of accurately measuring the CMOD of short crack specimens in the laboratory without affecting the crack tip behavior may be eliminated using the J-integral test procedure.

ftsZ is an essential cell division gene in Escherichia coli.

Abstract: The ftsZ gene is thought to be an essential cell division gene in Escherichia coli. We constructed a null allele of ftsZ in a strain carrying additional copies of ftsZ on a plasmid with a temperature-sensitive replication defect. This strain was temperature sensitive for cell division and viability, confirming that ftsZ is an essential cell division gene. Further analysis revealed that after a shift to the nonpermissive temperature, cell division ceased when the level of FtsZ started to decrease, indicating that septation is very sensitive to the level of FtsZ. Subsequent studies showed that nucleoid segregation was normal while FtsZ was decreasing and that ftsZ expression was not autoregulated. The null allele could not be complemented by lambda 16-2, even though this bacteriophage can complement the thermosensitive ftsZ84 mutation and carries 6 kb of DNA upstream of the ftsZ gene.

An Interplant Test of the Efficiency Wage Hypothesis

Abstract: © 1991 by the President, and Fellows of Harvard College and the Massachusetts Institute of Technology.

Tumor necrosis factor alpha mRNA and protein are present in human placental and uterine cells at early and late stages of gestation.

Abstract: Tumor necrosis factor alpha (TNF-alpha), a polypeptide that regulates cellular growth and modulates the synthesis of various cell surface and secreted molecules, has been identified in the pregnant uterus. To determine which specific cells transcribed and translated this gene, extraembryonic fetal tissues (placenta and membranes) and uterine tissue from early and late stages of gestation were analyzed for TNF-alpha mRNA by in situ hybridization using biotinylated antisense and sense TNF-alpha probes, and for immunoreactive TNF-alpha using two monoclonal antibodies. Tumor necrosis factor-alpha transcripts and protein were identified in both extraembryonic and maternal cells. In first-trimester placental villi, TNF-alpha mRNA was present in syncytiotrophoblast but was low to absent in cytotrophoblast and villous stromal cells. Decidual and epithelial cells in maternal tissues contained TNF-alpha transcripts. In term placentas, both syncytiotrophoblast and villous stromal cells contained TNF-alpha mRNA, and transcripts were present in maternal cells in the decidua adjacent to the extraplacental membranes. In both first-trimester and term tissues, coincident expression of TNF-alpha mRNA and immunoreactive TNF-alpha was demonstrated. The results of this study show that TNF-alpha is synthesized by cells in both extraembryonic membranes and maternal tissues during human gestation and that transcription in specific types of cells is influenced by gestational age. These observations are consistent with a major role for TNF-alpha in the dynamic developmental events of human pregnancy.

Evolutionary Stability in Asymmetric Games

Abstract: We examine dynamic models of evolutionary selection processes on asymmetric two-player games. Conditions are established under which dynamic selection processes will yield outcomes that respect iterated strict dominance. The addition of a stability requirement ensures that outcomes will be Nash equilibria. However, we find that stable outcomes need not respect weak dominance, and hence need not yield perfect equilibria. We conclude that evolutionary arguments readily motivate such equilibrium oncepts as rationalizability and Nash equilibrium, but appear to provide little basis for even such simple refinements of Nash equilibrium as the recommendation that dominated strategies not be played.

A multidimensional latent trait model for measuring learning and change.

Abstract: A latent trait model is presented for the repeated measurement of ability based on a multidimensional conceptualization of the change process. A simplex structure is postulated to link item performance under a given measurement condition or occasion to initial ability and to one or more modifiabilities that represent individual differences in change. Since item discriminations are constrained to be equal within a measurement condition, the model belongs to the family of multidimensional Rasch models. Maximum likelihood estimators of the item parameters and abilities are derived, and an example provided that shows good recovery of both item and ability parameters. Properties of the model are explored, particularly for several classical issues in measuring change.

Longitudinal Analysis of Time, Engagement, and Achievement in At-Risk versus Non-Risk Students

Abstract: This longitudinal study investigated the effects of time spent in academic instruction and time engaged on elementary students' academic achievement gains. Three groups were compared over grades as follows: (a) an at-risk experimental group of low-socioeconomic status (SES) students for whom teachers implemented classwide peer tutoring (CWPT) beginning with the second semester of first grade continuing through Grade 3; (h) an equivalent at-risk control group; and (c) a non-risk comparison group of students of average- to high-SES. In both the control and comparison groups, teachers employed conventional instructional practices over Grades 1 through 3. Results indicated significant group differences in the time spent in academic instruction, engagement, and gains on the subtests of the Metropolitan Achievement Test that favored the experimental and comparison groups over the control group. Implications include the effectiveness of CWPT for at-risk students and the continuing vulnerability of at-risk studen...

Social Interactions of Speech, and Language-Impaired Children

Abstract: Social interactions among preschool children were classified into four groups according to language ability: normally developing English, specific language impairment (SLI), speech impairment (SI),...

The assessment and prediction of functional disability in rheumatoid arthritis.

Abstract: We assessed functional disability with the Stanford Health Assessment Questionnaire Functional Disability Index (FDI) in 1,274 patients with rheumatoid arthritis (RA) followed longitudinally for up to 12 years. The rate of functional loss increased sharply after the first clinic visit. Half of patients with RA (median survival time) will reach FDI scores of about 1 in 2 years, 2 in 6 years, and 2.5 in 10 years after the first clinic visit, levels that correspond to moderate, severe and very severe loss of functional ability. Functional outcomes may be predicted by simple demographic and clinical assessments, the best of which are self-assessed measures of global severity, pain and function.

Individual differences in infant visual attention: are short lookers faster processors or feature processors?

Abstract: Individual differences in the duration of infants' visual fixations are reliable and stable and have been linked to differential cognitive performance; short-looking infants typically perform better than long-looking infants. 4 experiments tested the possibility of whether short lookers' superiority on perceptual-cognitive tasks is attributable to attention to the featural details of visual stimuli, or simply to differences in the speed or efficiency of visual processing. To do this, the performance of long- and short-looking 4-month-olds was examined on separate discrimination tasks that could be solved only by processing either featural or global information. The global task was easier than the featural task, but as the amount of time allotted for infants to solve either type of task was decreased, short lookers' performance was superior to that of long lookers. These results thus lend support to a speed or efficiency of stimulus processing interpretation of infant fixation duration.

Analytic solution of a two-dimensional hydrogen atom. I. Nonrelativistic theory

Abstract: The two-dimensional hydrogen problem is solved analytically. In the nonrelativistic case, exact formulas for energy eigenvalues and eigenfunctions for both the discrete and continuous parts of the spectrum, dipole matrix elements, dc Stark effect, single- and two-photon transition rates, and fine and hyperfine structures are obtained. Comparison is made between the two- and the three-dimensional cases. Some interesting aspects of the solution unique to the two-dimensional case are discussed.

Neural mechanisms underlying corticospinal and rubrospinal control of limb movements.

Abstract: Publisher Summary This chapter reviews the present understanding of the organization and functional properties of descending systems and recent advances that have come from single unit recording in awake monkeys using new techniques that reveal the synaptic connections of single premotor neurons with motoneurons of agonist and antagonist muscles The technique of spike-triggered averaging of electromyogram activity in awake monkeys is yielding new information at the level of individual premotor neurons concerning the sign, strength, and distribution of synaptic effects from descending systems to spinal motoneurons The chapter emphasizes the role of descending systems in the control of limb movements, although it is recognized that locomotion and other motor behaviors involving axial, head, and/or facial muscles may involve similar principles It also emphasizes motor control in primates, although relevant data from the cat and other species will be included where no primate data are available

Psychosocial factors in chronic spinal cord injury pain.

Abstract: Chronic pain is a problem among patients with spinal cord injuries, but the psychosocial factors associated with spinal cord injury (SCI) pain are not well understood. To understand SCI pain further, 54 patients (19 with quadriplegia and 35 with paraplegia) completed the Beck Depression Inventory, State-Trait Anxiety Inventory, Profile of Mood States, Acceptance of Disability Scale and SCI Interference Scale. Forty-two patients stated they had SCI pain and completed the Multidimensional Pain Inventory and the Pain Experience Scale. Results revealed that anger and negative cognitions were associated with greater pain severity. Patients who reported pain in response to a general prompt experienced more severe pain than patients who reported pain only when directly questioned about the presence of pain, but these different reporting groups did not differ on emotional variables. Those who were less accepting of their disability reported greater pain severity. Additionally, patients who perceived a significant other expressing punishing responses (e.g., expressing anger at the patients or ignoring the patients) to their pain behaviors reported more severe pain. Level of lesion, completeness of injury, surgical fusion and/or instrumentation and veteran status were not associated with pain severity. Finally, pain was associated with emotional distress over and above the distress associated with the SCI itself. Overall, psychosocial factors, not physiological factors, were most closely associated with the experience of pain. Multidimensional aspects of pain are used to explain these findings and suggest that treatment should be directed at the emotional and cognitive sequelae of chronic SCI pain.