bluuebunny/crossref_metadata_2025 huggingface dataset:
Effect of Lipids from Erabu Sea Snake, Laticauda semifasciata, on Plasma Glucose, Insulin, and Adipocytokine Concentrations of Normal and Streptozotocin-Diabetic Mice
Authors: Shirai Nobuya , Higuchi Tomoyuki , Suzuki Hiramitsu , Shimizu Eiji
Published: July 2006

Aims: To clarify the influence of Erabu sea snake lipid on levels of plasma insulin and adipocyte-derived hormones. Methods: Normal male mice (6 months) and streptozotocin-diabetic mice (a single administration, 150 mg/kg i.p.) were fed diets containing 10% fat as either lard or a mixture of 5% lard and 5% sea snake lipid for 4 months. Results: The normal mice on the sea snake lipid diet had a significantly lower plasma glucose concentration (198 ± 16 mg/dl; 148 ± 11 mg/dl) than those mice on the lard diet. Although plasma insulin concentrations were not influenced by the dietary fat type, leptin (10 ± 1 ng/ml; 16 ± 2 ng/ml) and adiponectin (18 ± 1 µg/ml; 21 ± 1 µg/ml) concentrations were significantly higher in the sea snake lipid group than in the lard group. However, these effects of a sea snake lipid intake were not evident in the streptozotocin-diabetic mice. Conclusion: The results suggest that the decrease in plasma glucose following the intake of sea snake lipids could be related to a corresponding increase in leptin and adiponectin level.
Cortical Gene Expression in the Vitamin E-Deficient Rat: Possible Mechanisms for the Electrophysiological Abnormalities of Visual and Neural Function
Authors: Hyland Stephen , Muller David , Hayton Samantha , Stoecklin Elisabeth , Barella Luca
Published: July 2006

In mammals, severe and chronic deficiency of vitamin E (α-tocopherol) is associated with a characteristic neurological syndrome. Previously, we have shown that this syndrome is accompanied by electrophysiological abnormalities of neural and visual function. To investigate the molecular basis of the observed abnormalities, we used microarrays to monitor the expression of ∼14,000 genes in the cerebral cortex from rats which had received diets containing 0, 1.25 and 5.0 mg/kg diet of all-rac-α-tocopheryl acetate for 14 months. Compared to the groups receiving 1.25 and 5.0 mg/kg α-tocopheryl acetate, a total of 11 genes were statistically significantly upregulated (≧1.3-fold) and 34 downregulated (≤1.3-fold) in the vitamin E-deficient group. Increased expression was observed for the genes encoding the antioxidant enzyme catalase and the axon guidance molecule tenascin-R, while decreased expression was detected for genes encoding protein components of myelin and determinants of neuronal signal propagation. Thus our observations suggest that vitamin E deficiency results in transcriptional alterations in the cerebral cortex of the rat which are consistent with the observed neurological and electrophysiological alterations.
Bursting Without Slow Kinetics: A Role for a Small World?
Authors: Shao Jie , Tsao Tzu-Hsin , Butera Robert
Published: July 2006

Bursting, a dynamical phenomenon whereby episodes of neural action potentials are punctuated by periodic episodes of inactivity, is ubiquitous in neural systems. Examples include components of the respiratory rhythm generating circuitry in the brain stem, spontaneous activity in the neonatal rat spinal cord, and developing neural networks in the retina of the immature ferret. Bursting can also manifest itself in single neurons. Bursting dynamics require one or more kinetic processes slower than the timescale of the action potentials. Such processes usually manifest themselves in intrinsic ion channel properties, such as slow voltage-dependent gating or calcium-dependent processes, or synaptic mechanisms, such as synaptic depression. In this note, we show rhythmic bursting in a simulated neural network where no such slow processes exist at the cellular or synaptic level. Rather, the existence of rhythmic bursting is critically dependent on the connectivity of the network and manifests itself only when connectivity is characterized as small world. The slow process underlying the timescale of bursting manifests itself as a progressive synchronization of the network within each burst.
Error Entropy in Classification Problems: A Univariate Data Analysis
Authors: Silva Luís M. , Felgueiras Carlos S. , Alexandre Luís A. , Marques de Sá J.
Published: July 2006

Entropy-based cost functions are enjoying a growing attractiveness in unsupervised and supervised classification tasks. Better performances in terms both of error rate and speed of convergence have been reported. In this letter, we study the principle of error entropy minimization (EEM) from a theoretical point of view. We use Shannon's entropy and study univariate data splitting in two-class problems. In this setting, the error variable is a discrete random variable, leading to a not too complicated mathematical analysis of the error entropy. We start by showing that for uniformly distributed data, there is equivalence between the EEM split and the optimal classifier. In a more general setting, we prove the necessary conditions for this equivalence and show the existence of class configurations where the optimal classifier corresponds to maximum error entropy. The presented theoretical results provide practical guidelines that are illustrated with a set of experiments with both real and simulated data sets, where the effectiveness of EEM is compared with the usual mean square error minimization.
Excessive Noise Injection Training of Neural Networks for Markerless Tracking in Obscured and Segmented Environments
Authors: Unsworth C. P. , Coghill G.
Published: July 2006

In this letter, we demonstrate that the generalization properties of a neural network (NN) can be extended to encompass objects that obscure or segment the original image in its foreground or background. We achieve this by piloting an extension of the noise injection training technique, which we term excessive noise injection (ENI), on a simple feedforward multilayer perceptron (MLP) network with vanilla backward error propagation to achieve this aim. Six tests are reported that show the ability of an NN to distinguish six similar states of motion of a simplified human figure that has become obscured by moving vertical and horizontal bars and random blocks for different levels of obscuration. Four more extensive tests are then reported to determine the bounds of the technique. The results from the ENI network were compared to results from the same NN trained on clean states only. The results pilot strong evidence that it is possible to track a human subject behind objects using this technique, and thus this technique lends itself to a real-time markerless tracking system from a single video stream.
Assessing Neuronal Coherence with Single-Unit, Multi-Unit, and Local Field Potentials
Authors: Zeitler Magteld , Fries Pascal , Gielen Stan
Published: July 2006

The purpose of this study was to obtain a better understanding of neuronal responses to correlated input, in particular focusing on the aspect of synchronization of neuronal activity. The first aim was to obtain an analytical expression for the coherence between the output spike train and correlated input and for the coherence between output spike trains of neurons with correlated input. For Poisson neurons, we could derive that the peak of the coherence between the correlated input and multi-unit activity increases proportionally with the square root of the number of neurons in the multi-unit recording. The coherence between two typical multi-unit recordings (2 to 10 single units) with partially correlated input increases proportionally with the number of units in the multi-unit recordings. The second aim of this study was to investigate to what extent the amplitude and signal-to-noise ratio of the coherence between input and output varied for single-unit versus multi-unit activity and how they are affected by the duration of the recording. The same problem was addressed for the coherence between two single-unit spike series and between two multi-unit spike series. The analytical results for the Poisson neuron and numerical simulations for the conductance-based leaky integrate-and-fire neuron and for the conductance-based Hodgkin-Huxley neuron show that the expectation value of the coherence function does not increase for a longer duration of the recording. The only effect of a longer duration of the spike recording is a reduction of the noise in the coherence function. The results of analytical derivations and computer simulations for model neurons show that the coherence for multi-unit activity is larger than that for single-unit activity. This is in agreement with the results of experimental data obtained from monkey visual cortex (V4). Finally, we show that multitaper techniques greatly contribute to a more accurate estimate of the coherence by reducing the bias and variance in the coherence estimate.
Impact of Co-Opetition on Firm Competitive Behavior: An Empirical Examination
Authors: Gnyawali Devi R. , He Jinyu , Madhavan Ravindranath (“Ravi”)
Published: July 2006

The authors examine how co-opetition—simultaneous cooperation and competition—affects firms'competitive behavior, proposing that differential structural positions among firms in a coopetitive network reflect resource asymmetries among them and that such asymmetries lead to differences in the volume and diversity of competitive actions undertaken by those firms. Data on cooperative network structure and competitive actions from the steel industry suggest that the firm's centrality is positively related to its volume of competitive actions and that its structural autonomy is positively related to the diversity of such actions. Moreover, market diversity moderates the impact of centrality and structural autonomy on competitive behavior.
The Role of Leader-Member Exchange in the Performance Appraisal Process
Authors: Elicker Joelle D. , Levy Paul E. , Hall Rosalie J.
Published: July 2006

Performance appraisal (PA) feedback research suggests that agreement of others' performance feedback with one's own views strongly determines feedback reactions, yet inconsistent results of feedback interventions motivate a search for additional influences. The authors propose that supervisor-subordinate exchange relationships create a social context that substantially influences the PA discussion and feedback reactions. Key mediating variables in this process are employee voice during the PA session and justice judgments. Structural equation modeling analyses of longitudinal data support our model. Exchange relationship showed strong, mediated effects on feedback reactions, whereas performance rating discrepancies had minimal unique effects.
The Journal of Management's First 30 Years
Authors: Van Fleet David D. , Ray Dennis F. , Bedeian Arthur G. , Downey H. Kirk , Hunt J. G. , Griffin Ricky W. , Dalton Dan , Vecchio Robert P. , Kacmar K. Michele , Feldman Daniel C.
Published: July 2006

The Journal of Management, now one of the preeminent journals in the discipline, completed its 30th year of publication in 2004. To provide an understanding of the journal's development, this article reviews its origins as recounted in reflections by its past editors, examines three decades of publication statistics, and provides a brief look at the journal's possible future. Thus, this is a history of the journal, a glimpse into the work of its editors, and a brief case study of organizational evolution.
A Longitudinal Investigation of Coping Processes During a Merger: Implications for Job Satisfaction and Organizational Identification
Authors: Amiot Catherine E. , Terry Deborah J. , Jimmieson Nerina L. , Callan Victor J.
Published: July 2006

This study tested the utility of a stress and coping model of employee adjustment to a merger. Two hundred and twenty employees completed both questionnaires (Time 1: 3 months after merger implementation; Time 2: 2 years later). Structural equation modeling analyses revealed that positive event characteristics predicted greater appraisals of self-efficacy and less stress at Time 1. Self-efficacy, in turn, predicted greater use of problem-focused coping at Time 2, whereas stress predicted a greater use of problem-focused and avoidance coping. Finally, problem-focused coping predicted higher levels of job satisfaction and identification with the merged organization (Time 2), whereas avoidance coping predicted lower identification.
The Effects of Critical Team Member Assertiveness on Team Performance and Satisfaction
Authors: Pearsall Matthew J. , Ellis Aleksander P. J.
Published: July 2006

In an effort to extend theory and research linking personality to team effectiveness, this study used the workflow networks literature to investigate the effects of critical team member dispositional assertiveness on team performance and satisfaction. Results from 64 teams working on a command-and-control simulation indicated that critical team member dispositional assertiveness positively affected team performance and team satisfaction. Results also indicated that both of those effects were due to improvements in the team's transactive memory system.
Post-institutionalized Chinese and Eastern European children: Heterogeneity in the development of emotion understanding
Authors: Camras Linda A. , Perlman Susan B. , Fries Alison B. Wismer , Pollak Seth D.
Published: July 2006

Post-institutionalized Chinese and Eastern European children participated in two emotion understanding tasks. In one task, children selected facial expressions corresponding to four emotion labels (happy, sad, angry, scared). The second task required children to match facial expressions to stories describing situations for these emotions. While both post-institutionalized groups scored lower than the never-institutionalized children, those from China performed better than those from Eastern Europe. Post-institutionalized children's performance was predicted by their age at adoption.
The personal belief in a just world and domain-specific beliefs about justice at school and in the family: A longitudinal study with adolescents
Authors: Dalbert Claudia , Stoeber Joachim
Published: July 2006

This article investigates the relationship between the personal belief in a just world (BJW) and domain-specific beliefs about justice and examines how justice cognitions impact on adolescents' development, particularly on their achievement at school and their subjective well-being. A longitudinal questionnaire study with German adolescents aged 14–19 years was conducted over a period of five to eight months. The pattern of results revealed that evaluations of the school climate and of the family climate as being just were two distinct phenomena, both of which impacted on the personal BJW, which in turn affected the domain-specific beliefs about justice. However, the domain-specific beliefs about justice did not impact on each other directly. Moreover, an evaluation of the family climate (but not of the school climate) as being just reduced depressive symptoms, whereas depressive symptoms did not weaken the evaluation of one's family as being just. The evaluation of the school climate as being just improved the grades received in the next school report, whereas the grades received did not affect the justice evaluation of the school climate. Finally, all relationships persisted when controlling for age and gender. In sum, the pattern of findings supports the notion that justice cognitions impact on development during adolescence.
Group status, group bias, and adolescents' reasoning about the treatment of others in school contexts
Authors: Horn Stacey S.
Published: July 2006

This study investigated how social group status and group bias are related to adolescents' reasoning about social acceptance. Ninth and eleventh-grade students ( N = 379) were asked to make judgments about the inclusion of individuals in school activities based on their peer crowd membership. The results of the study revealed that both participants' and the targets' social reference group status were related to adolescents' judgments about participation in school activities. Overall, high status group members were chosen more than low status group members to participate in school activities. Adolescents who identified themselves with high status groups, however, were significantly more likely to choose a high status target than adolescents identifying with low status groups or those listing no group at all. Further, these adolescents were more likely than adolescents who identified themselves with low status groups or listed no group to use conventional reasoning and less likely to use moral reasoning when justifying their judgments.
Childhood aggression, depressive symptoms, and peer rejection: The mediational model revisited
Authors: Morrow Michael T. , Hubbard Julie A. , McAuliffe Meghan D. , Rubin Ronnie M. , Dearing Karen F.
Published: July 2006

The goals of the current study were to investigate whether peer rejection mediated the relation between aggression and depressive symptoms in childhood, and if so, whether this mediational pathway was specific to the reactive subtype of aggression. Participants were 57 second-grade children (22 girls and 35 boys). Data on reactive aggression, proactive aggression, depressive symptoms, and peer rejection were collected from four sources (parents, teachers, peers, and self). Results revealed that reactive aggression, but not proactive aggression, was positively related to depressive symptoms. Furthermore, peer rejection partially mediated the relation between reactive aggression and depressive symptoms.
Theory of mind and inhibitory control in three cultures: Conflict inhibition predicts false belief understanding in Germany, Costa Rica and Cameroon
Authors: Chasiotis Athanasios , Kiessling Florian , Hofer Jan , Campos Domingo
Published: July 2006

This study investigates the relationship of theory of mind and inhibitory control in three samples from Europe, Africa and Latin America differing in relevant socioeconomic and psychological background. The relationship between false belief understanding and inhibitory control was tested using samples of 3 to 5 year-old preschoolers from Germany ( N = 116), Costa Rica ( N = 82) and Cameroon ( N = 116). Inhibitory control and theory of mind were examined using test batteries. Age, gender, siblings, language understanding and mother's education were controlled. Results of regression analyses controlling for moderating effects of culture show a culture-independent relation between conflict inhibition and false belief understanding while delay inhibition is not a significant predictor for false belief understanding across cultures. Conflict inhibition is discussed as a universal developmental prerequisite for the development of theory of mind in the preschool years.
Relations between Chinese mothers' parenting practices and social withdrawal in early childhood
Authors: Nelson Larry J. , Hart Craig H. , Wu Bo , Yang Chongming , Roper Susanne Olsen , Jin Shenghua
Published: July 2006

Researchers have identified specific parenting practices used by parents of preschoolers in mainland China (e.g., physical coercion, overprotection, shaming, directiveness, encouragement of modesty). Some of the intrusive practices have been linked to social withdrawal in western societies (e.g., United States, Canada). It seemed important to examine these associations in China because recent research suggests that young Chinese children who exhibit wariness in peer settings may be at risk for negative outcomes such as peer rejection. Therefore, the purpose of this study was to examine the relation between Chinese parenting practices and preschoolers' social withdrawal. Mothers of preschool-age children from mainland China ( N = 446) completed self-report parenting questionnaires. Teachers rated children's reticent, solitary-passive, solitary-active, and modest behaviors. Results showed that (a) maternal directiveness was positively associated with reticent behavior in girls and negatively associated with solitary-passive behavior in boys, (b) maternal overprotection, for girls, was positively related to both reticent behavior and solitary-passive behavior, and negatively related to modest behavior, (c) coercion was positively associated with solitary-active and reticent behavior in girls, and (d) shaming was positively related to all forms of withdrawn behaviors in boys and girls, as well as positively related to modest behavior in boys.
Family and Work Influences on the Transition to College Among Latina Adolescents
Authors: Sy Susan R.
Published: July 2006

This study investigates the effect of family obligations and part-time work on Latina adolescents' stress and academic achievement during the transition to college. One hundred seventeen Latina college students from immigrant families completed surveys assessing the mother-daughter relationship, family obligations, work-school conflict, school and work-related stress, and academic achievement. Path analyses revealed a complex set of relations among family, work, and school variables. Latina students who spent more time with family experienced lower school stress and higher academic achievement. However, those who more frequently engaged in language brokering (i.e., translating for parents) experienced higher school stress. In addition, students experiencing higher levels of work-school conflict had increased stress levels in work and school, as well as lower academic achievement. This study has important implications for educators and community-based organizations wishing to promote Latina adolescents' pursuit of higher education.
Evaluating Short-Form Versions of the CES-D for Measuring Depressive Symptoms Among Immigrants From Mexico
Authors: Grzywacz Joseph G. , Hovey Joseph D. , Seligman Laura D. , Arcury Thomas A. , Quandt Sara A.
Published: July 2006

This article examines the feasibility of using a short-form version of the Center for Epidemiologic Studies–Depression Scale (CES-D) in community mental health research with Mexican immigrants. Several features of three published short versions of the CES-D were examined using data combined from seven diverse Mexican immigrant samples from across the United States ( N= 685). Results indicate that published short-form versions of the CES-D are reliable, they account for most of the variance in scores from the full CES-D, and there is little evidence that the use of short forms attenuates associations with other concepts relevant to understanding the mental health of Mexican immigrants. Although additional validation research is necessary, the results of this study suggest that short-form versions of the CES-D can be used to study mental health among Mexican immigrants.
A Comparison of HIV-Related Factors Among Seropositive Brazilian, South American, and Puerto Rican Gay Men in the United States
Authors: Bianchi Fernanda T. , Reisen Carol A. , Zea Maria Cecilia , Poppen Paul J. , Echeverry John J.
Published: July 2006

Latino men who have sex with men are a group at high risk for HIV infection. Much of the research addressing attitudes and behaviors related to HIV among Latinos in the United States has overlooked differences based on nationality. Brazilian immigrants, in particular, are an understudied subgroup of Latinos. This study compared HIV-positive Brazilian gay men ( n = 75) with their Spanish-speaking counterparts from South America ( n = 103) and Puerto Rico ( n = 61) on a variety of HIV-related factors. Results failed to reveal any significant group differences in disclosure of serostatus or in behaviors relevant to sexual risk. Some differences in demographic characteristics, reasons for immigration, and acculturation, however, did emerge among the three groups. Implications for aggregation of Latino subgroups in HIV-related programs are discussed.
Alcohol Use Disorders in National Samples of Mexicans and Mexican-Americans
Authors: Borges Guilherme , Medina-Mora Maria Elena , Lown Anne , Ye Yu , Robertson Marjorie J. , Cherpitel Cheryl , Greenfield Tom
Published: July 2006

The authors show associations between immigration and alcohol disorders using data from the 1995 and 2000 U.S. National Alcohol Surveys and the 1998 Mexico National Household Survey on Addictions. The prevalence of alcohol dependence was 4.8% for the Mexicans, 4.2% for the Mexico-born immigrants, and 6.6% for the U.S.-born Mexican Americans. They found a general lack of significance for the immigration variables with few consistent dose-response findings for alcohol use disorders. High acculturation was associated with higher risks for women; however, unexpectedly, high acculturation was associated with lower risks for males. Among Mexican Americans, the impact of immigration to the United States on the prevalence of alcohol use disorders differs by gender. Male and female differences and possible sources of immigrant selection are important issues for future research.
Pursuing Social Change Online
Authors: Earl Jennifer
Published: July 2006

This article examines the distribution and architecture of web sites hosting or directly linking to opportunities to participate in four online activist tactics: online petitioning, boycotting, and e-mailing and letter-writing campaigns. Specifically, this article addresses five basic structural questions: (1) Are opportunities to engage in these tactics usually organized around social movement organizations and/or actors? (2) Do sites tend to host or link to these tactics? (3) On average, how tactically specialized or tactically diversified are sites? (4) How are these tactics distributed across different types of sites? and (5) How many implementations of each tactic were offered per web site? Contributions include a clearer understanding of online opportunities to participate in these four tactics and the introduction of an innovative, methodological technique that generates best approximations of reachable populations of online content, which can be randomly sampled when those populations are large.
Postmodernism and Criticality in Information Systems Research
Authors: Mitev Nathalie N.
Published: July 2006

This article identifies a gap in the inclusion of the postmodern concept in critical information systems (IS) research. Starting from the three critical tasks, insight, critique, and transformative definition, we argue that the second task of critique has been less commonly addressed. Filling that gap can begin by exploring how critical management studies have used both critical theory and postmodernism. The authors draw on Alvesson and Deetz’s (1996) argumentation that these two bodies of literature can complement each other and cohabit. There is no need for a unitary critical position, but there is currently an imbalance in critical IS research, as Habermassian approaches have remained untouched by a poststructuralist critique. Postmodern approaches are more cautious on transformative definition, and they are well suited to the task of critique. They have also been applied to examine modernist themes such as performativity and managerialism, which relate to underresearched and undercritiqued modernist concepts in IS.
Politics, Complexity, and Systems Implementation
Authors: Peszynski Konrad J. , Corbitt Brian J.
Published: July 2006

This article identifies the role of power and politics in systems implementation under a critical epistemology. Research in information systems has typically adopted a positivist or interpretive approach. This article highlights the use of the critical epistemology, providing a case study exploring the power and politics in the systems implementation process. Previous implementation studies that have investigated human and political factors involved in systems implementation have taken a simplistic view of power and politics. A critical, poststructuralist view of power provides a lens for observing the selection and implementation of an enterprise-wide learning management system. Such an approach has important implications for research methods as the critical epistemology needed is challenged by acceptance of bias and the need to expose it as an important factor in explaining success and/or failure in systems implementation. This article illustrates how useful a critical approach is in seeking out the real impact of power and politics in systems implementation and offers an alternative perspective that provides more insight into the observed process.
Understanding the Multidimensionality of Group Development
Authors: Chang Artemis , Duck Julie , Bordia Prashant
Published: July 2006

This article presents a three-dimensional definition space of the group development literature that differentiates group development models on three dimensions: content, population, and path dependency. The multidimensional conceptualization structures and integrates the vast group development literature, enabling direct comparison of competing theories. The utility of this definition space is demonstrated by using the relative positioning of two seemingly competing group development models—the punctuated equilibrium model and the integrative model—to demonstrate their complementarity. The authors also show how organizational researchers and practitioners can use the three-dimensional definition space to select an appropriate theoretical model for the group or group process with which they are working.
The Meaning of Consensus and Blocking for Cohousing Groups
Authors: Renz Mary Ann
Published: July 2006

This study examined the meanings of consensus and a block of consensus for 47 residents of one forming and three formed cohousing communities. Interviews revealed that the groups in this study constructed the meaning of consensus in their communities over time. Residents' metaphors for consensus revealed a multilayered and often contradictory understanding of consensus as a process that was capable of leading to a decision no member had previously envisioned, to increased member insight, and to firmer relationships within the group. Descriptions of a consensus block revealed themes related to the motives for blocking and to the pivotal role blocking has in improving the group's thinking, stopping its progress, transforming its energy, isolating members, or building community.
Do Cardiac Surgery Report Cards Reduce Mortality? Assessing the Evidence
Authors: Epstein Andrew J.
Published: July 2006

Provider report cards feature prominently in ongoing efforts to improve patient quality. A well-known example is the cardiac surgery report-card program started in New York, which publicly compares hospital and surgeon performance. Public report cards have been associated with decreases in cardiac surgery mortality, but there is substantial disagreement over the source(s) of the improvement. This article develops a conceptual framework to explain how report-card-related responses could result in lower mortality and reviews the evidence. Existing research shows that report cards have not greatly changed referral patterns. How much providers increased their quality of care and altered their selection of patients remains unresolved, and alternative explanations have not been well studied. Future research should expand the number of states and years covered and exploit the variation in institutional features to improve our understanding of the relationship between report cards and outcomes.
Market Structure and Technical Efficiency in the Hospital Services Industry: A DEA Approach
Authors: Bates Laurie J. , Mukherjee Kankana , Santerre Rexford E.
Published: July 2006

This article uses data envelopment analysis and multiple regression analysis to examine empirically the impact of various market-structure elements on the technical efficiency of the hospital services industry in various metropolitan areas of the United States. Market-structure elements include the degree of rivalry among hospitals, extent of HMO activity, and health insurer concentration. The DEA results show the typical hospital services industry experienced 11 percent inefficiency in 1999. Moreover, multiple regression analysis indicates the level of technical efficiency varied directly across metropolitan hospital services industries in response to greater HMO activity and private health insurer concentration in the state. The analysis suggests the degree of rivalry among hospitals had no marginal effect on technical efficiency at the industry level. Evidence also implies that the presence of a state Certificate of Need law was not associated with a greater degree of inefficiency in the typical metropolitan hospital services industry.
Determinants of Cost among People Who Died in VA Nursing Homes
Authors: Yu Wei , Wagner Todd H. , Barnett Paul G.
Published: July 2006

We examined final stays of elderly patients (65 or more years of age) who died in 111 VA nursing homes in fiscal year 2000 (N = 4,897) to evaluate determinants of the cost of final nursing home stays. We analyzed cost and its two main components (length of stay and intensity of care) by primary disease, age, race or ethnicity, gender, and benefit-eligibility type. We found that disease rather than age was the dominant factor influencing the cost of final nursing home stays. After controlling for six common diagnoses, age was not associated with cost. Marital status and race or ethnicity were also significant predictors but accounted for less variation than illnesses. Incorporating illness into models that predict future demand for nursing home use provides greater precision than using age alone, especially as diseases and their treatments change through time.
May-Thurner Syndrome Presenting With Venous Claudication
Authors: Sulzdorf Linda
Published: July 2006

More than half of patients who present with left-sided iliac vein obstruction have an underlying iliocaval compression syndrome caused by anatomic compression of the left common iliac vein by the overlying right common iliac artery. Because young women are particularly at risk for this condition, commonly referred to as May-Thurner syndrome, suspicion should increase for female patients presenting with iliofemoral obstruction following prolonged bed rest or presenting postpartum. Symptoms are variable, depending on the chronicity of the disease and available collateral circulation, and range from edema to claudication to phlegmasia cerulea dolens from progressive or acute obstruction. The following is a case study of a patient who presented with severe venous claudication caused by postpartum occlusion of her left external iliac vein. Her left common iliac vein was found to be chronically occluded due to iliocaval compression.
Carcinoid Heart Disease
Authors: Ruvo Charlene , Keller Susan
Published: July 2006

Carcinoid heart disease is a rare, metastatic disease that occurs predominantly in the right heart. The tricuspid and pulmonic valves are affected, leading to right heart failure, which results in increased morbidity and mortality. This case report demonstrates classic echocardiography findings associated with carcinoid heart disease. Cardiac sonography is a useful tool for the detection and diagnosis of carcinoid heart disease.
B-Flow Sonography for Detecting Portal Venous Stenosis After Liver Transplantation
Authors: Clevert D.-A. , Stickel M. , Michaely H. J. , Loehe F. , Graeb C. , Steitz H. O. , Strautz T. , Flach P. , Schoenberg S. O. , Jauch K. W. , Reiser M. F.
Published: July 2006

A case of a patient in his early 60s with a portal vein stenosis after liver transplantation (LTx) detected by sonography in B-flow mode is reported. Two weeks after LTx, the patient developed ascites and severe alteration of liver function tests. Color Doppler (CD) demonstrated a stenosis in the portal vein with a maximum flow of 340 cm/sec. Due to aliasing, correct assessment of stenosis diameter was not possible by means of CD. However, by using the B-flow imaging technique, slow and fast velocities in the pre-, intra-, and poststenotic segment could be detected without aliasing or overwriting. In addition, a second stenosis in the portal vein was identified. For the follow-up outcome of patients, it is essential to detect and treat this complication. After surgical intervention, graft function recovered and postoperative flow measurements showed a normal portal vein flow of 70 cm/sec in the poststenotic segment.
Discrepancies Between Echocardiographic Spectral Doppler and Catheterization Pressures
Authors: Coon Fern E. , Hanson Cyndie
Published: July 2006

As medical professionals, we strive to provide high-quality examinations that provide the information needed for physicians to make definitive diagnoses for their patients. The quality of examinations performed is consistently monitored and analyzed for correlation with other diagnostic modalities. The following case puzzled cardiac sonographers, pulmonologists, and cardiologists from several different institutions. Due to the discrepancies between echocardiographic and catheterization results, the patient underwent five echocardiograms, three of which were performed at the same institution as the two right heart catheterizations. Cardiologists and sonographers have trusted the modified Bernoulli’s equation to provide accurate and reproducible echocardiographic pressures. However, this case proved puzzling when the catheterization pressures were normal and the echocardiogram reported high pressures indicating significant pulmonary hypertension.
Interventional Echocardiography
Authors: Chadwell Kimberly
Published: July 2006

The topic of interventional echocardiography is a difficult one to define; is it an application that is used to assess and alter therapy and medications, alter patient management, guide an invasive procedure, plan an invasive procedure, or evaluate the efficacy of an invasive procedure? This review helps to define interventional echocardiography techniques as those used to either (1) guide an invasive procedure, such as during pericardiocentesis or atrial septostomy, or (2) plan and evaluate an invasive procedure, such as in the case of valvuloplasty or myectomy.
Optical Resolution of Amino Acid Esters by N-Protected Aspartylphenylalanine Esters
Authors: Oyama Kiyotaka , Itoh Mikio , Nonaka Yuji
Published: July 2006

A new method was studied for optical resolution of racemic amino acid esters by using, as resolving agents, N-protected l-α-aspartyl-l-phenylalanine alkyl esters, typically, N-benzyloxycarbonyl-l-α-aspartyl-l-phenylalanine methyl ester, the precursor to the synthetic sweetener aspartame. Thus, when the dipeptide and racemic amino acid ester were mixed in solvents, precipitation took place by formation of salt preferentially with d-amino acid ester to effect the optical resolution.
Multiple Electrostatic Interaction of Polycationic Chitosan Oilgomers with Nucleic Acids: Polyamine Promoted Stabilization of the A-Form of RNA and DNA in Aqueous Solutions
Authors: Motomura Tadahiro , Aoyama Yasuhiro
Published: July 2006

Polycationic chitosan oligomers 1n (n = 2–6), i.e., β-1,4-linked glucosamine oligomers, were found to bind to nucleic acids in aqueous solutions at pH 7.2 via multiple electrostatic interaction. The binding of trimer and higher homologues (1n, n ≥ 3) is especially efficient owing to an (at least) three-point simultaneous ammonio phosphate formation. Upon binding of 1n (n ≥ 3), the double-helical structure in the A-form of poly(A)·poly(U), a synthetic RNA, is significantly stabilized as revealed by enhancement of its helix-to-coil transition (melting) temperatures. Upon binding of 1n (n ≥ 3), calf thymus DNA in the B-form undergoes a drastic conformational change to the A-form, as revealed by circular dichrosim spectroscopy. In marked contrast, chitosan dimer (12) and diamine and monoamine references only induce the B-to-C transition within the B-family. The significance of the multiple electrostatic interaction and the cooperativity of the glucosamine residues in 1n are discussed.
Abnormal Diels–Alder Reaction of 5-Alkoxyoxazoles with Tetracyanoethylene and X-Ray Crystal Structure of an Adduct
Authors: Ibata Toshikazu , Isogami Yasushi , Nakawa Hiroyuki , Tamura Hatsue , Suga Hiroyuki , Shi Xiaolan , Fujieda Hiroki
Published: July 2006

The reaction of 2-alkyl- or 2-aryl-substituted 5-methoxy-4-(p-nitrophenyl)oxazoles with tetracyanoethylene gave methyl esters of 5-substituted 3,3,4,4-tetracyano-2-(p-nitrophenyl)-3,4-dihydro-2H-pyrrole-2-carboxylic acids as formal [3 + 2] cycloadducts through oxazole ring opening. Zwitterionic mechanisms were proposed on the basis of the solvent effect on the reaction. The molecular structure of 2-isopropyl-substituted product was determined by means of X-ray crystallography. Crystals of the cycloadduct are orthorhombic with space group Pcab having unit-cell dimensions of a = 17.998 (2), b = 27.188 (6), c = 15.833 (3) Å, and Z = 16, which contains two crystallographically independent molecules. The final R value is 0.070 for 4629 observed reflections.
Tetrakis(thiolato)nickelate(II), [Ni(RS)4]2−; Ligand Dissociation and Electronic Spectra
Authors: Yamamura Takeshi , Arai Hiroki
Published: July 2006

The dissociation feature of nickel complexes of arenethiolates, [Ni(RS)4]2− (RSH = p-CH3C6H4SH, m-CH3C6H4SH, C6H5SH, p-ClC6H4SH, p-NO2C6H4SH) in DMSO was studied by spectrophotometric method. 1H NMR experiment on [Ni(RS)4]2− (RSH = 2,4,6-trideuteriobenzenethiol) in DMSO-d6 revealed that this system obeys the following equilibrium scheme generating the diamagnetic nickel species, [Ni(RS)3(solv)]− and [Ni(RS)2(solv)2] (solv = solvent ligand). Dissociation constants Kd, Ke, and Kd′ were calculated from the NMR data.

Intrinsic UV-vis. absorption spectra of [Ni(RS)n(solv)4−n](n−2)− (RS− = C6H5S−, n = 2, 3, 4) were derived from the least squares fitting analyses of the absorption change data obtained under different concentrations of RS−. The absorption spectrum of [Ni(t-C4H9S)4]2− was also measured in solid state. Crystal field calculations for both [Ni(C6H5S)4]2− and [Ni(t-C4H9S)4]2− were examined. The results were compared with those of [NiX4]2− (X− = Cl−, Br−, I−), as well as the nickel exchanged aspartate transcarbamoylase. The structures of [Ni(RS)n(solv)4−n](n−2)− were discussed.
Preparation and Characterization of trans- and cis-Halogenobis(vicinal-dioximato)nitrosylruthenium(III) Complexes
Authors: Fukuchi Takashi
Published: July 2006

The complexes of nitrosylruthenium(III) with vicinal-dioximato ligands, [Ru(vic-dioximato)2X(NO)] (vic-dioximato = 2,3-butanedione dioximato (Hdmo), 1,2-diphenylethanedione dioximato (Hdpo), or 1,2-cyclohexanedione dioximato (Hcho); X = Cl, Br, or I), and the complexes of carbonylruthenium(II) with Hdpo, [Ru(Hdpo)2(CO)L] (L = H2O or pyridine), were synthesized. The results of the 1H, 13C NMR, and IR spectra showed that the trans and cis isomers were present in some of the nitrosylruthenium(III) complexes.
Kinetics and Mechanisms of Photo-Induced Reduction of Iodine by Monoamine-N-polycarboxylate Ions in an Aqueous Solution
Authors: Kimura Masaru , Nakazawa Fumiko , Tsukahara Keiichi
Published: July 2006

The photo-induced reduction kinetics of iodine by monoamine-N-polycarboxylate ions, such as nitrilotriacetic acid (H3nta), iminodiacetic acid (H2ida), 2-hydroxyethyliminodiacetic acid (H2hida), as well as o-, m-, and p-isomers of N-(carboxyphenyl)iminodiacetic acid (H3cpida), were made in an aqueous solution containing iodide ions in excess over the pH range 1.6–7.6; the photo-induced reductions of iodine by triethylamine (TEA) and tris(2-hydroxyethyl)amine (TEOA) were also studied. The reactive species are a I2−• radical anion, produced in the primary photoreaction, and a fully deprotonated species of monoamine-N-polycarboxylate, TEOA, or TEA. Both hydrogen ion and complex-forming metal ions, such as copper(II) and zinc(II), were strong inhibitors for all of the reactions investigated. The role of the lone electron pair on the amine nitrogen is discussed.
Molecular Structures of HT-[MM′Cl2(μ-Me2Ppy)2] (MM′ = Pd2, PdPt, and Pt2; Me2Ppy = 2-(Dimethylphosphino)pyridine) and HT-[Pd2Cl2(μ-Ph2Ppy)2] (Ph2Ppy = 2-(Diphenylphosphino)pyridine)
Authors: Suzuki Takayoshi , Iitaka Naoyuki , Kurachi Saeko , Kita Masakazu , Kashiwabara Kazuo , Ohba Shigeru , Fujita Junnosuke
Published: July 2006

Crystal structures of Pd(I) and Pt(I) dinuclear complexes, [MM′Cl2(μ-Me2Ppy)2] (MM′ = Pd2 (1), PdPt (2), and Pt2 (3)) and [Pd2Cl2(μ-Ph2Ppy)2] (4), were determined by the single crystal X-ray diffraction method. Crystal data and final R values are: 1, triclinic, , a = 10.019(2), b = 10.902(2), c = 9.062(1) Å, α = 97.75(2), β = 102.45(2), γ = 82.64(2)°, V = 952.7(3) Å3, Z = 2, and R = 0.047; 2, monoclinic, P21/n, a = 16.532(2), b = 19.205(3), c = 13.260(2) Å, β = 93.86(2)°, V = 4200(1) Å3, Z = 8, and R = 0.043; 3, monoclinic, P21/n, a = 16.515(5), b = 19.095(10), c = 13.233(4) Å, β = 93.15(3)°, V = 4167(3) Å3, Z = 8, and R = 0.047; 4, monoclinic, C2/c, a = 30.505(4), b = 17.896(2), c = 12.983(1) Å, β = 98.52(1)°, V = 7009(1) Å3, Z = 8, and R = 0.041. All of the complexes were found to be the head-to-tail isomer of a side-by-side type dinuclear structure. The metal–metal bond distances of 2.584(1) Å in 1, 2.561(1) Å in 2, 2.573(1) Å in 3, and 2.594(1) Å in 4 are relatively short compared with those in the analogous dinuclear complexes bridged by diphosphine ligands. All of the M–P, M–N, and M–Cl distances in Me2Ppy complexes become shortened in the order of the Pd2 > PdPt > Pt2 complexes.
57Fe Mössbauer Spectra, Crystal Structure, and Spin-Crossover Behavior of [Fe(mbpN)(lut)]BPh4
Authors: Maeda Yonezo , Noda Yosuke , Oshio Hiroki , Takashima Yoshimasa
Published: July 2006

A new spin-crossover complex [Fe(mbpN)(lut)]BPh4 (H2mbpN; N,N′-bis[(2-hydroxy-5-methylphenyl)phenylmethylene]-4-azaheptane-1,7-diamine and lut; 3,4-dimethylpyridine) is reported. The structure of this complex was determined at 293 K, and the temperature dependence of the 57Fe Mössbauer spectra and magnetic susceptibilities was examined. The complex undergoes a faster spin-state interconversion than the lifetime of the 57Fe excited state (1 × 10−7 s). More importantly, it has been found that the quadrupole splittings of the complex show the lowest value at intermediate spin-state transformations. This behavior is illustrated by a model in which the electric field gradient of the high-spin state has the opposite sign with that of the low-spin state. The monoclinic crystal of [Fe(mbpN)(lut)]BPh4 is of space group P21/a, with a = 14.664(5), b = 37.269(4), c = 10.061(5) Å, β = 90.97(3)°, Z = 4, and refinement to R = 0.079 and Rw = 0.084. The bond distances of Fe–Oav (1.912(5) Å), Fe–Nimineav (2.080(6) Å), Fe–Namine (2.141(6) Å), and Fe–Npyridine (2.145(6) Å) are close to the expected values for the high-spin species.
Oxidation of Phosphatidylcholine Liposomes in Aqueous Dispersions Induced by Copper and Iron
Authors: Yoshida Yasukazu , Niki Etsuo
Published: July 2006

The oxidations of phosphatidylcholine liposomes in aqueous dispersions induced by copper and iron have been studied aiming specifically at elucidating the action of copper ion in the chain initiation of the oxidation of liposomal membranes. Both copper(II) and iron(III) ions induced steady oxidations and the addition of t-butyl hydroperoxide enhanced the rate of oxidation. The reduction of hydroperoxides present initially in the liposomes by triphenylphosphine markedly reduced the rate of oxidation. The rate of oxidation induced by copper(II) ion was proportional to the first power of phosphatidylcholine concentration and to the half power of both copper(II) ion and t-butyl hydroperoxide concentrations, suggesting that the oxidation was initiated by the oxygen radicals formed in the decomposition of hydroperoxide by copper(II) and copper(I) ions. The anionic dipalmitoylphosphatidic acid added into the liposomes enhanced the rate of oxidation induced by metal ions, whereas the addition of cationic octadecylamine showed little effect on the rate of oxidation.