Showing papers by "Case Western Reserve University published in 2000"

Brain-computer interface technology: a review of the first international meeting

Abstract: Over the past decade, many laboratories have begun to explore brain-computer interface (BCI) technology as a radically new communication option for those with neuromuscular impairments that prevent them from using conventional augmentative communication methods. BCI's provide these users with communication channels that do not depend on peripheral nerves and muscles. This article summarizes the first international meeting devoted to BCI research and development. Current BCI's use electroencephalographic (EEG) activity recorded at the scalp or single-unit activity recorded from within cortex to control cursor movement, select letters or icons, or operate a neuroprosthesis. The central element in each BCI is a translation algorithm that converts electrophysiological input from the user into output that controls external devices. BCI operation depends on effective interaction between two adaptive controllers, the user who encodes his or her commands in the electrophysiological input provided to the BCI, and the BCI which recognizes the commands contained in the input and expresses them in device control. Current BCI's have maximum information transfer rates of 5-25 b/min. Achievement of greater speed and accuracy depends on improvements in signal processing, translation algorithms, and user training. These improvements depend on increased interdisciplinary cooperation between neuroscientists, engineers, computer programmers, psychologists, and rehabilitation specialists, and on adoption and widespread application of objective methods for evaluating alternative methods. The practical use of BCI technology depends on the development of appropriate applications, identification of appropriate user groups, and careful attention to the needs and desires of individual users. BCI research and development will also benefit from greater emphasis on peer-reviewed publications, and from adoption of standard venues for presentations and discussion.

Prospective Randomized Trial of Docetaxel Versus Best Supportive Care in Patients With Non–Small-Cell Lung Cancer Previously Treated With Platinum-Based Chemotherapy

Abstract: PURPOSE: To evaluate whether treatment with single-agent docetaxel would result in longer survival than would best supportive care in patients with non–small-cell lung cancer who had previously been treated with platinum-based chemotherapy. Secondary end points included assessment of response (docetaxel arm only), toxicity, and quality of life. PATIENTS AND METHODS: Patients with performance statuses of 0 to 2 and stage IIIB/IV non–small-cell lung cancer with either measurable or evaluable lesions were eligible for entry onto the study if they had undergone one or more platinum-based chemotherapy regimens and if they had adequate hematology and biochemistry parameters. They were excluded if they had symptomatic brain metastases or if they had previously been treated with paclitaxel. Patients were stratified by performance status and best response to cisplatin chemotherapy and were then randomized to treatment with docetaxel 100 mg/m2 (49 patients) or 75 mg/m2 (55 patients) or best supportive care. Patient...

Rethinking Resistance and Recognizing Ambivalence: A Multidimensional View of Attitudes Toward an Organizational Change

Abstract: In this article I review studies of resistance to change and advocate new research based on a reconceptualization of individual responses to change as multidimensional attitudes. A challenging question for research and practice arises: How can we balance the organizational need to foster ambivalent attitudes toward change and the individual need to minimize the potentially debilitating effects of ambivalence? I conclude by highlighting the importance of examining the evolution of employee responses to change over time and the need to understand responses to change proposals that emerge from bottom-up. egalitarian change processes.

Perspectives and results on the stability and stabilizability of hybrid systems

Abstract: This paper introduces the concept of a hybrid system and some of the challenges associated with the stability of such systems, including the issues of guaranteeing stability of switched stable systems and finding conditions for the existence of switched controllers for stabilizing switched unstable systems. In this endeavour, this paper surveys the major results in the (Lyapunov) stability of finite-dimensional hybrid systems and then discusses the stronger, more specialized results of switched linear (stable and unstable) systems. A section detailing how some of the results can be formulated as linear matrix inequalities is given. Stability analyses on the regulation of the angle of attack of an aircraft and on the PI control of a vehicle with an automatic transmission are given. Other examples are included to illustrate various results in this paper.

Agency and trust mechanisms in consumer satisfaction and loyalty judgments

Abstract: The authors propose a framework for understanding key mechanisms that shape satisfaction in individual encounters, and loyalty across ongoing exchanges In particular, the framework draws together two distinct approaches: (1) agency theory, rooted in the economic approach, that views relational exchanges as encounters between principals (consumers) and agents (service providers) and (2) trust research that adopts a psychological approach toward consumer-provider relationships In so doing, the authors specify how trust mechanisms cooperate and compete with agency mechanisms to affect satisfaction in individual encounters and influence loyalty in the long run Because a multidimensional conceptualization of trust is used, the hypothesized framework offers a fine-grained understanding of the interrelated mechanisms The high level of specificity allows extraction of multiple propositions, facilitates empirical testing, and encourages theoretical development of the proposed model Several directions to guide future research are provided

Rapid Hematopoietic Recovery After Coinfusion of Autologous-Blood Stem Cells and Culture-Expanded Marrow Mesenchymal Stem Cells in Advanced Breast Cancer Patients Receiving High-Dose Chemotherapy

Abstract: PURPOSE: Multipotential mesenchymal stem cells (MSCs) are found in human bone marrow and are shown to secrete hematopoietic cytokines and support hematopoietic progenitors in vitro. We hypothesized that infusion of autologous MSCs after myeloablative therapy would facilitate engraftment by hematopoietic stem cells, and we investigated the feasibility, safety, and hematopoietic effects of culture-expanded MSCs in breast cancer patients receiving autologous peripheral-blood progenitor-cell (PBPC) infusion. PATIENTS AND METHODS: We developed an efficient method of isolating and culture-expanding a homogenous population of MSCs from a small marrow-aspirate sample obtained from 32 breast cancer patients. Twenty-eight patients were given high-dose chemotherapy and autologous PBPCs plus culture-expanded MSC infusion and daily granulocyte colony-stimulating factor. RESULTS: Human MSCs were successfully isolated from a mean ± SD of 23.4 ± 5.9 mL of bone marrow aspirate from all patients. Expansion cultures generat...

Neurodevelopmental and Functional Outcomes of Extremely Low Birth Weight Infants in the National Institute of Child Health and Human Development Neonatal Research Network, 1993–1994

Abstract: Objectives. The purposes of this study were to report the neurodevelopmental, neurosensory, and functional outcomes of 1151 extremely low birth weight (401–1000 g) survivors cared for in the 12 participating centers of the National Institute of Child Health and Human Development Neonatal Research Network, and to identify medical, social, and environmental factors associated with these outcomes. Study Design. A multicenter cohort study in which surviving extremely low birth weight infants born in 1993 and 1994 underwent neurodevelopmental, neurosensory, and functional assessment at 18 to 22 months9 corrected age. Data regarding pregnancy and neonatal outcome were collected prospectively. Socioeconomic status and a detailed interim medical history were obtained at the time of the assessment. Logistic regression models were used to identify maternal and neonatal risk factors for poor neurodevelopmental outcome. Results. Of the 1480 infants alive at 18 months of age, 1151 (78%) were evaluated. Study characteristics included a mean birth weight of 796 ± 135 g, mean gestation (best obstetric dates) 26 ± 2 weeks, and 47% male. Birth weight distributions of infants included 15 infants at 401 to 500 g; 94 at 501 to 600 g; 208 at 601 to 700 g; 237 at 701 to 800 g; 290 at 801 to 900 g; and 307 at 901 to 1000 g. Twenty-five percent of the children had an abnormal neurologic examination, 37% had a Bayley II Mental Developmental Index Conclusion. ELBW infants are at significant risk of neurologic abnormalities, developmental delays, and functional delays at 18 to 22 months9 corrected age.

Targeted disruption of the class B scavenger receptor CD36 protects against atherosclerotic lesion development in mice

Abstract: Macrophage scavenger receptors have been implicated as key players in the pathogenesis of atherosclerosis. To assess the role of the class B scavenger receptor CD36 in atherogenesis, we crossed a CD36-null strain with the atherogenic apo E–null strain and quantified lesion development. There was a 76.5% decrease in aortic tree lesion area (Western diet) and a 45% decrease in aortic sinus lesion area (normal chow) in the CD36-apo E double-null mice when compared with controls, despite alterations in lipoprotein profiles that often correlate with increased atherogenicity. Macrophages derived from CD36-apo E double-null mice bound and internalized more than 60% less copper-oxidized LDL and LDL modified by monocyte-generated reactive nitrogen species. A similar inhibition of in vitro lipid accumulation and foam cell formation after exposure to these ligands was seen. These results support a major role for CD36 in atherosclerotic lesion development in vivo and suggest that blockade of CD36 can be protective even in more extreme proatherogenic circumstances.

Clustering competence in emotional intelligence: Insights from the Emotional Competence Inventory.

Abstract: Appeared in Reuven Bar-On and James D.A. Parker (editors)(2000), Handbook of Emotional Intelligence, San Francisco: Jossey-Bass, pages 343-362. Correspondence should be addressed to Richard E. Boyatzis, Department of Organizational Behavior, Weatherhead School of Management, Case Western Reserve University, 10900 Euclid Avenue, Cleveland, Ohio, USA, 44106-7235. Reproduced by The Consortium for Research on Emotional Intelligence in Organizations with special permission of the authors.

Poorer behavioral and developmental outcome more than 10 years after treatment for iron deficiency in infancy.

Abstract: Objective. To determine the long-term effects of iron deficiency in infancy. Design. Longitudinal follow-up study of children who had been tested and treated for iron deficiency as infants. Setting. Periurban community near San Jose, Costa Rica. Participants. Of the original 191 participants, 87% were reevaluated at 11 to 14 years old (average age: 12.3 years). The children were free of iron deficiency and growing normally by US standards. Those who had chronic, severe iron deficiency in infancy ( n = 48) were compared with those who had good iron status before and/or after iron therapy in infancy ( n = 114). Outcome Measures. Comprehensive set of cognitive, socioemotional, and motor tests and measures of school functioning. Results. Children who had severe, chronic iron deficiency in infancy scored lower on measures of mental and motor functioning. After control for background factors, differences remained statistically significant in arithmetic achievement and written expression, motor functioning, and some specific cognitive processes (spatial memory, selective recall, and tachistoscopic threshold). More of the formerly iron-deficient children had repeated a grade and/or been referred for special services or tutoring. Their parents and teachers rated their behavior as more problematic in several areas, agreeing in increased concerns about anxiety/depression, social problems, and attention problems. Conclusions. Severe, chronic iron deficiency in infancy identifies children who continue at developmental and behavioral risk >10 years after iron treatment.

Impaired endochondral ossification and angiogenesis in mice deficient in membrane-type matrix metalloproteinase I

Abstract: Membrane-type matrix metalloproteinase I (MT1-MMP)-deficient mice were found to have severe defects in skeletal development and angiogenesis. The craniofacial, axial, and appendicular skeletons were severely affected, leading to a short and domed skull, marked deceleration of postnatal growth, and death by 3 wk of age. Shortening of bones is a consequence of decreased chondrocyte proliferation in the proliferative zone of the growth plates. Defective vascular invasion of cartilage leads to enlargement of hypertrophic zones of growth plates and delayed formation of secondary ossification centers in long bones. In an in vivo corneal angiogenesis assay, null mice did not have angiogenic response to implanted FGF-2, suggesting that the defect in angiogenesis is not restricted to cartilage alone. In tissues from null mice, activation of latent matrix metalloproteinase 2 was deficient, suggesting that MT1-MMP is essential for its activation in vivo.

Performance Productivity and Quality of Frontline Employees in Service Organizations

Abstract: To understand mechanisms that govern the productivity and quality of frontline employees (FLEs), this study (1) provides a conceptual distinction between frontline productivity and quality, (2) proposes an extended role theory-based model for mapping the influence of key antecedents and consequences of FLE productivity and quality, and (3) examines the effects of coping resources—boss support and task control—in helping employees cope with the inherent productivity-quality tension in frontline jobs. Using data from 159 customer service and 147 bill collection representatives, the author examines proposed hypotheses through multiple-group path analysis. The results indicate support for the distinction between productivity and quality. Moreover, with increasing burnout levels, FLEs are found to maintain their productivity levels while their quality deteriorates directly. Relative to boss support, task control emerges as a more powerful resource in aiding FLEs in coping with role tension. Key implic...

Gender differences in erotic plasticity: the female sex drive as socially flexible and responsive

Abstract: Responding to controversies about the balance between nature and culture in determining human sexuality, the author proposes that the female sex drive is more malleable than the male in response to sociocultural and situational factors. A large assortment of evidence supports 3 predictions based on the hypothesis of female erotic plasticity: (a) Individual women will exhibit more variation across time than men in sexual behavior, (b) female sexuality will exhibit larger effects than male in response to most specific sociocultural variables, and (c) sexual attitude-behavior consistency will be lower for women than men. Several possible explanations for female erotic plasticity are reviewed, including adaptation to superior male political and physical power, the centrality of female change (from no to yes) as a prerequisite for intercourse, and the idea that women have a milder sex drive than men.

The age of anxiety? Birth cohort change in anxiety and neuroticism, 1952-1993.

Abstract: Two meta-analyses find that Americans have shifted toward substantially higher levels of anxiety and neuroticism during recent decades. Both college student (adult) and child samples increased almost a full standard deviation in anxiety between 1952 and 1993 (explaining about 20% of the variance in the trait). The average American child in the 1980s reported more anxiety than child psychiatric patients in the 1950s. Correlations with social indices (e.g., divorce rates, crime rates) suggest that decreases in social connectedness and increases in environmental dangers may be responsible for the rise in anxiety. Economic factors, however, seem to play little role. Birth cohort, as a proxy for broad social trends, may be an important influence on personality development, especially during childhood.

Brain potentials of recollection and familiarity

Abstract: It is widely hypothesized that separate recollection and familiarity processes contribute to recognition memory. The present research measured event-related brain potentials (ERPs) from 128 head locations to identify patterns of brain activity related to recollection and familiarity. In two experiments, subjects performed a recognition memory task requiring discrimination between previously studied words, similar words that changed plurality between study and test, and new words (following Hintzman & Curran, 1994). The FN400 ERP component (300–500 msec) varied with the familiarity of words (new>studied = similar). The parietal component (400–800 msec) was associated with the recollection of plurality (studied > similar = new). Differences in the timing and spatial topography of the FN400 and parietal effects support the view that familiarity and recollection arise from distinct neurocognitive processes.

Knowledge Spillovers and Patent Citations: Evidence from a Survey of Inventors

Abstract: It is well understood that the non-rival nature of knowledge as a productive asset creates the possibility of "knowledge spillovers," whereby investments in knowledge creation by one party produce external benefits by facilitating innovation by other parties. At least since Zvi Griliches's (1979) seminal paper on measuring the contributions of R&D to economic growth, economists have been attempting to quantify the extent and impact of knowledge spillovers. One line of research of this type has utilized patent citations to identify a "paper trail" that may be associated with knowledge flows between firms.' Very little of this research has attempted to determine the modes or mechanisms of communication that actually permit knowledge to flow. Further, most of the work has simply assumed that citations or other proxies are sufficiently correlated with knowledge flows to allow statistical analysis of the proxies to be informative regarding the underlying phenomenon of interest. This paper reports on a preliminary attempt to improve this situation. The idea for this survey came from R&D managers whom we were interviewing to test whether the picture of knowledge flows produced by patent citations was consistent with the managers' impressions. One of these managers commented that he could not let us talk to the scientists who worked for him, but that he could not stop uls from contacting them via the postal address that appears on their issued patents. The survey results suggest that communication between inventors is reasonably irnportant, and that patent citations do provide an indication of communication, albeit one that also carries a fair amount of noise.

Patterns and correlates of agreement between parent, teacher, and male adolescent ratings of externalizing and internalizing problems.

Abstract: The authors examined how well 394 triads of male youths, caregivers, and teachers agreed about youth problems reported on the Achenbach checklists. Dyadic agreement was measured through difference scores (subtracting the raw score of youth self-report from the caregiver's or teacher's score for shared items), q correlations between pairs of raters across items, and D2 (generalized distance between item profiles) for both externalizing and internalizing items. Teachers reported fewer internalizing and externalizing problems than did caregivers or youths. Teacher-youth disagreement was higher for African American than European American males about externalizing criteria. Caregiver depression and stress (but not paternal antisocial behavior or maternal substance abuse) correlated with higher disagreement with other informants about all criteria. These factors appear to increase disagreement about the level of problems but not about specific symptom patterns.

Effect of antibiotic therapy on the density of vancomycin-resistant enterococci in the stool of colonized patients.

Abstract: Background Colonization and infection with vancomycin-resistant enterococci have been associated with exposure to antibiotics that are active against anaerobes. In mice that have intestinal colonization with vancomycin-resistant enterococci, these agents promote high-density colonization, whereas antibiotics with minimal antianaerobic activity do not. Methods We conducted a seven-month prospective study of 51 patients who were colonized with vancomycin-resistant enterococci, as evidenced by the presence of the bacteria in stool. We examined the density of vancomycin-resistant enterococci in stool during and after therapy with antibiotic regimens and compared the effect on this density of antianaerobic agents and agents with minimal antianaerobic activity. In a subgroup of 10 patients, cultures of environmental specimens (e.g., from bedding and clothing) were obtained. Results During treatment with 40 of 42 antianaerobic-antibiotic regimens (95 percent), high-density colonization with vancomycin-resistant ...

Structural basis for the fracture toughness of the shell of the conch Strombus gigas

Abstract: Natural composite materials are renowned for their mechanical strength and toughness: despite being highly mineralized, with the organic component constituting not more than a few per cent of the composite material, the fracture toughness exceeds that of single crystals of the pure mineral by two to three orders of magnitude The judicious placement of the organic matrix, relative to the mineral phase, and the hierarchical structural architecture extending over several distinct length scales both play crucial roles in the mechanical response of natural composites to external loads Here we use transmission electron microscopy studies and beam bending experiments to show that the resistance of the shell of the conch Strombus gigas to catastrophic fracture can be understood quantitatively by invoking two energy-dissipating mechanisms: multiple microcracking in the outer layers at low mechanical loads, and crack bridging in the shell's tougher middle layers at higher loads Both mechanisms are intimately associated with the so-called crossed lamellar microarchitecture of the shell, which provides for 'channel' cracking in the outer layers and uncracked structural features that bridge crack surfaces, thereby significantly increasing the work of fracture, and hence the toughness, of the material Despite a high mineral content of about 99% (by volume) of aragonite, the shell of Strombus gigas can thus be considered a 'ceramic plywood' and can guide the biomimetic design of tough, lightweight structures

A Randomized, Placebo-Controlled 12-Month Trial of Divalproex and Lithium in Treatment of Outpatients With Bipolar I Disorder

Abstract: Background Long-term outcomes are often poor in patients with bipolar disorder despite treatment; more effective treatments are needed to reduce recurrences and morbidity. This study compared the efficacy of divalproex, lithium, and placebo as prophylactic therapy. Methods A randomized, double-blind, parallel-group multicenter study of treatment outcomes was conducted over a 52-week maintenance period. Patients who met the recovery criteria within 3 months of the onset of an index manic episode (n=372) were randomized to maintenance treatment with divalproex, lithium, or placebo in a 2:1:1 ratio. Psychotropic medications were discontinued before randomization, except for open-label divalproex or lithium, which were gradually tapered over the first 2 weeks of maintenance treatment. The primary outcome measure was time to recurrence of any mood episode. Secondary measures were time to a manic episode, time to a depressive episode, average change from baseline in Schedule for Affective Disorders and Schizophrenia–Change Version subscale scores for depression and mania, and Global Assessment of Function scores. Results The divalproex group did not differ significantly from the placebo group in time to any mood episode. Divalproex was superior to placebo in terms of lower rates of discontinuation for either a recurrent mood episode or depressive episode. Divalproex was superior to lithium in longer duration of successful prophylaxis in the study and less deterioration in depressive symptoms and Global Assessment Scale scores. Conclusions The treatments did not differ significantly on time to recurrence of any mood episode during maintenance therapy. Patients treated with divalproex had better outcomes than those treated with placebo or lithium on several secondary outcome measures.

Inflammatory Mechanisms in Alzheimer's Disease: Inhibition of β-Amyloid-Stimulated Proinflammatory Responses and Neurotoxicity by PPARγ Agonists

Abstract: Alzheimer's disease (AD) is characterized by the extracellular deposition of β-amyloid fibrils within the brain and the subsequent association and phenotypic activation of microglial cells associated with the amyloid plaque. The activated microglia mount a complex local proinflammatory response with the secretion of a diverse range of inflammatory products. Nonsteroidal anti-inflammatory drugs (NSAIDs) are efficacious in reducing the incidence and risk of AD and significantly delaying disease progression. A recently appreciated target of NSAIDs is the ligand-activated nuclear receptor peroxisome proliferator-activated receptor γ (PPARγ). PPARγ is a DNA-binding transcription factor whose transcriptional regulatory actions are activated after agonist binding. We report that NSAIDs, drugs of the thiazolidinedione class, and the natural ligand prostaglandin J2 act as agonists for PPARγ and inhibit the β-amyloid-stimulated secretion of proinflammatory products by microglia and monocytes responsible for neurotoxicity and astrocyte activation. The activation of PPARγ also arrested the differentiation of monocytes into activated macrophages. PPARγ agonists were shown to inhibit the β-amyloid-stimulated expression of the cytokine genes interleukin-6 and tumor necrosis factor α. Furthermore, PPARγ agonists inhibited the expression of cyclooxygenase-2. These data provide direct evidence that PPARγ plays a critical role in regulating the inflammatory responses of microglia and monocytes to β-amyloid. We argue that the efficacy of NSAIDs in the treatment of AD may be a consequence of their actions on PPARγ rather than on their canonical targets the cyclooxygenases. Importantly, the efficacy of these agents in inhibiting a broad range of inflammatory responses suggests PPARγ agonists may provide a novel therapeutic approach to AD.

Detection of preinvasive cancer cells

Abstract: Early-warning changes in precancerous epithelial cells can now be spotted in situ. More than 85% of all cancers originate in the epithelium that lines the internal surfaces of organs throughout the body. Although these are readily treatable provided they are diagnosed in one of the preinvasive stages1, early lesions are often almost impossible to detect. Here we present a new optical-probe technique based on light-scattering spectroscopy that is able to detect precancerous and early cancerous changes in cell-rich epithelia.

Controversies regarding definition of neonatal hypoglycemia: suggested operational thresholds.

Abstract: The definition of clinically significant hypoglycemia remains one of the most confused and contentious issues in contemporary neonatology. In this article, some of the reasons for these contentions are discussed. Pragmatic recommendations for operational thresholds, ie, blood glucose levels at which clinical interventions should be considered, are offered in light of current knowledge to aid health care providers in neonatal medicine. Future areas of research to resolve some of these issues are also presented.