bluuebunny/crossref_metadata_2025 huggingface dataset:
A Comparative Study of Community‐ and Nursing Home‐Acquired Empyema Thoracis
Authors: El Solh Ali A. , Alhajjhasan Ahmad , Ramadan Fadi H. , Pineda Lilibeth A.
Published: September 2007

OBJECTIVES: To compare the clinical presentation, microbiological features, and outcomes of patients with community‐acquired empyema (CAE) with those of patients with nursing home‐acquired empyema (NHAE).

DESIGN: A retrospective observational study.

SETTING: Three tertiary care centers.

PARTICIPANTS: One hundred fourteen patients admitted from the community and 55 patients transferred from nursing homes.

MEASUREMENTS: Baseline sociodemographic information, activities of daily living, Charlson Comorbidity Index score, and clinica, and microbiologic data were obtained. Outcome was assessed at hospital discharge and 6 months postdischarge.

RESULTS: Patients admitted from nursing homes had a delayed presentation, with dyspnea, weight loss, and anemia as the predominant manifestation. Patients with CAE presented more acutely, with fever, cough, and chest pain. Anaerobic organisms were more commonly isolated from patients with NHAE. The success rate of nonsurgical intervention was significantly lower for the NHAE patients than for the CAE group (39% vs 63; P=.01). In‐hospital mortality was not significantly different between the two groups (NHAE, 18%; CAE, 8%; P=.09). In a Cox regression analysis, preadmission functional status (hazard ratio (HR)=1.26, 95% confidence interval (CI)=1.19–1.4; P<.001) and surgical intervention (HR=0.47, 95% CI=0.24–0.92; P=.03) were the only variables highly correlated with long‐term outcome.

CONCLUSION: Patients admitted with NHAE have distinctly different clinical and microbiological presentation from that of patients with CAE. Because of the delayed presentation in patients with NHAE, medical treatment alone may be associated with higher rate of failure. Surgical therapy should be considered for selected cases, with the aim of improving long‐term survival.
Attitudes and Preferences of Korean‐American Older Adults and Caregivers on End‐of‐Life Care
Authors: Kwak Jung , Salmon Jennifer R.
Published: September 2007

A growing body of literature suggests that diverse attitudes toward the end of life exist across and within ethnic minority groups. This focus‐group pilot study examined social and cultural factors influencing views of Korean‐American older adults and caregivers on advance care planning and hospice care. A total of 20 older adults and 16 caregivers in west central Florida participated in one of four focus groups. This study found diverse attitudes among Korean Americans toward end‐of‐life care and cultural and structural barriers to advance care planning and hospice use. Older adults and caregivers both expressed a lack of knowledge about advance care planning and hospice and agreed that the family would make the final decision about the end‐of‐life care, while acknowledging the challenge of initiating communications about treatment preferences. They interpreted the Korean value of filial piety to support both curative and palliative treatment. The traditional norm of home death and importance of physician communication influenced preferences for hospice and advance care planning, respectively. Future outreach and education efforts should include development of culturally sensitive educational and communication tools and collaboration with ethnic community organizations and healthcare providers in the dissemination and education of these instruments.
Profile of Cognitive Impairment in Chronic Heart Failure
Authors: Vogels Raymond L.C. , Oosterman Joukje M. , Van Harten Barbera , Scheltens Philip , Van Der Flier Wiesje M. , Schroeder‐Tanka Jutta M. , Weinstein Henry C.
Published: September 2007

OBJECTIVES: To determine the frequency and pattern of cognitive dysfunction in outpatients with chronic congestive heart failure (CHF) and to identify the corresponding demographic and clinical correlates.

DESIGN: Case‐control study.

SETTING: Outpatient clinic in a community hospital.

PARTICIPANTS: Sixty‐two outpatients with CHF, 53 controls diagnosed with cardiovascular disease uncomplicated by CHF (cardiac controls), and 42 healthy controls were investigated.

MEASUREMENTS: Neuropsychological assessment included tests of mental speed, executive function, memory, language, and visuospatial function. Composite z‐scores for five cognitive domains and mean z‐score for overall cognitive performance were computed. The cutoff score to indicate cognitive impairment was defined as the overall healthy participants' cognitive z‐score minus 2 standard deviations. Independent demographic and clinical predictors of cognitive impairment were identified using linear regression analysis.

RESULTS: Patients with CHF showed a pattern of general cognitive impairment, including impairment of executive function, memory, language, mental speed, and attention. Twenty‐five percent (P=.04) of patients with CHF were classified as cognitively impaired, compared with 15% of the cardiac controls and 4% of the healthy controls. Independent predictors of cognitive impairment in patients with CHF were estimated intelligence, New York Heart Association class, and presence of the apolipoprotein (Apo)E ɛ4 allele.

CONCLUSION: Cognitive dysfunction is relatively common in patients with CHF, with deficits being most prominent in the domains of executive function, memory, language, and mental speed. Disease severity and ApoE genotype are likely to be important determinants for cognitive impairment in patients with chronic CHF.
Effect of Heat Treatment on Fracture Toughness (KIC) and Microstructure of a Fluorcanasite‐Based Glass‐Ceramic
Authors: Oh Won‐suck , Zhang Nai‐Zheng , Anusavice Kenneth J.
Published: September 2007

Purpose:
The purpose of this study was to test the hypothesis that the increase in fracture toughness of a fluorcanasite‐based glass‐ceramic is a linear function of crystal volume fraction.

Materials and Methods:
A total of 60 specimen bars (20 × 5 × 2 mm3) were cut from parent glass blocks, polished, annealed, randomly divided into six groups, nucleated at 680°C/4 hr, and crystallized at the following temperatures and times: (1) 850°C/0.5 hr, (2) 850°C/1 hr, (3) 850°C/3 hr, (4) 750°C/6 hr, (5) 800°C/6 hr, or (6) 850°C/6 hr. Indentation flaws were produced by a microhardness indenter at the center of one surface, and the prepared specimens were subjected to three‐point flexure loading with the severely flawed surface under tension at a crosshead speed of 0.5 mm/min. Flexural strength and fracture toughness (KIC) were calculated based on the indentation‐strength technique. Crystal volume fraction (Vc) was determined by quantitative stereology of scanning electron images of each group of ceramic specimens. Statistical analysis was performed using ANOVA and Duncan's multiple comparison test (α= 0.05).

Results:
The mean KIC and Vc values ranged from 2.7 to 3.9 MPa m1/2 and 37% to 71% within the crystallization temperature range of 750 to 850°C. Five statistical subsets of groups 1, 2/4, 3, 5, and 6 were determined as a function of crystallization temperature and holding time (Duncan's multiple comparison analysis; α= 0.05). The lowest and highest KIC and Vc values were associated with Groups 1 (850°C/0.5 hr) and 6 (850°C/6 hr), respectively. Fracture toughness increased linearly as a function of crystal volume fraction (correlation coefficient R2= 0.67). The fracture toughness increased by 45% when the crystal volume fraction increased by 92%.

Conclusions:
Mean KIC values increased as a linear function of crystal volume fraction in a fluorcanasite‐based glass‐ceramic within the crystallization temperature range of 750 to 850°C and at isothermal crystallization time range of 0.5 to 6 hours. The control of crystallization temperature and isothermal holding time should be optimized to generate tougher, more reliable ceramic prostheses in the shortest period of time.
Effect of Disinfection on the Dimensional Stability of Polyether Impression Materials
Authors: Yilmaz Handan , Aydin Cemal , Gul Basak , Yilmaz Caner , Semiz Mustafa
Published: September 2007

Purpose:
Difficulties in sterilizing impressions have led to chemical disinfection solutions as an alternative; however, some impression materials are more sensitive to humidity. For example, polyether impression materials are more hydrophilic. This study investigated the effect of three disinfecting methods on the dimensional stability of three polyether impression materials.

Materials and Methods:
Three polyether impression materials (P2, Impregum Penta Soft, and Impregum Penta) were submitted to the following treatments: spray disinfectant (Mikrozid Liquid), immersion in 2% glutaraldehyde solution (Super‐On), immersion in 0.525% sodium hypochlorite solution for 10 minutes, and a control group (not disinfected). Each group included five samples. After treatment, dimensional change was evaluated according to ISO 4823. The data were analyzed by 2‐way analysis of variance at α= 0.05.

Results:
The mean percentages of linear dimensional change of materials P2, Penta Soft, and Penta were –0.040%, 0.098%, and 0.100%, respectively. The dimensional change associated with different disinfectant agents mikrozid liquid, 2% glutaraldehyde, room air (control), and 0.525% sodium hypochlorite was 0.013%, 0.024%, 0.077%, and 0.096%, respectively. The interaction between the impression materials and the disinfectant treatment was not significant. The disinfectant agents can be classified in two groups as low‐ and high‐effected. The control group did not significantly differ from either group.

Conclusion:
From the standpoint of dimensional change, the disinfectants tested for 10 minutes caused no significant linear dimensional change in the polyether impression materials, compared with the control group.
The Role of Insider Influence in Mutual‐to‐Stock Conversions
Authors: CAROW KENNETH A. , COX STEVEN R. , RODEN DIANNE M.
Published: September 2007

Using a sample of 347 demutualizing thrifts from 1991 to 2004, we show that the level of inside participation is not a traditional signal of firm performance. We conclude that unanticipated inside participation reflects the incentives of insiders to reduce the size of the offer to influence the level of expected initial public offer (IPO) returns. We find unanticipated inside participation is related to lower offer size and higher initial returns, but we do not find a relationship between inside participation and post‐IPO performance.
Non‐stationary Hours in a DSGE Model
Authors: CHANG YONGSUNG , DOH TAEYOUNG , SCHORFHEIDE FRANK
Published: September 2007

The time series fit of dynamic stochastic general equilibrium (DSGE) models often suffers from restrictions on the long‐run dynamics that are at odds with the data. Using Bayesian methods we estimate a stochastic growth model in which hours worked are stationary and a modified version with permanent labor supply shocks. If firms can freely adjust labor inputs, the data support the latter specification. Once we introduce frictions in terms of labor adjustment costs, the overall time series fit improves and the model specification in which labor supply shocks and hours worked are stationary is preferred.
The Life‐Cycle Effects of House Price Changes
Authors: LI WENLI , YAO RUI
Published: September 2007

We develop a life‐cycle model that explicitly incorporates the dual feature of housing as both a consumption good and an investment asset. Our analysis indicates that the consumption and welfare consequences of house price changes on individual households vary significantly. In particular, the non‐housing consumption of young and old homeowners is much more sensitive to house price changes than that of middle‐aged homeowners. More importantly, while house price appreciation increases the net worth and consumption of all homeowners, it only improves the welfare of old homeowners. Renters and young homeowners are worse off due to higher lifetime housing consumption costs.
Is There a Dead Spot? New Evidence on FOMC Decisions Before Elections
Authors: HELLERSTEIN REBECCA
Published: September 2007

Using new data that chronicle the Fed's internal forecast of the output gap from 1973 to 1998, this paper tests for an electoral cycle in the decisions of the Federal Open Market Committee (FOMC). The paper provides evidence of a dead spot in the committee's decisions before presidential elections. For given values of these internal forecasts, the FOMC is less likely to decide to tighten monetary policy in the year preceding a presidential election than at other times.
Credit Markets and the Propagation of Monetary Policy Shocks
Authors: BOHÁČEK RADIM , MENDIZÁBAL HUGO RODRÍGUEZ
Published: September 2007

This paper analyzes the propagation of monetary policy shocks through the creation of credit in an economy. Models of the monetary transmission mechanism typically feature responses that last for a few quarters contrary to what the empirical evidence suggests. To propagate the impact of monetary shocks over time, these models introduce adjustment costs by which agents find it optimal to change their decisions slowly. This paper presents another explanation that does not rely on any sort of adjustment costs or stickiness. In our economy, agents own assets and make occupational choices. Banks intermediate between agents demanding and supplying assets. Our interpretation is based on the way banks create credit and how the monetary authority affects the process of financial intermediation through its monetary policy. As the central bank lowers the interest rate by buying government bonds in exchange for reserves, high productive entrepreneurs are able to borrow more resources from low‐productivity agents. We show that this movement of capital among agents sets in motion a response of the economy that resembles an expansionary phase of the cycle.
Dynamics of Persistence in International Inflation Rates
Authors: KUMAR MANMOHAN S. , OKIMOTO TATSUYOSHI
Published: September 2007

Characteristics of inflation play a key role in policy formulation and market analysis. Several studies have analyzed inflation persistence and reached diverging conclusions. In this paper, we investigate the dynamics of inflation persistence using fractionally integrated processes and find that there has been a clear decline in inflation persistence in the United States over the past two decades. We also show that the presence of fractional integration in inflation successfully explains previous diverging results. Lastly, we provide some international comparisons to examine the extent to which there has been a commensurate decline in inflation persistence in the other G7 economies.
How Sticky Is Sticky Enough? A Distributional and Impulse Response Analysis of New Keynesian DSGE Models
Authors: KORENOK OLEG , SWANSON NORMAN R.
Published: September 2007

In this paper, we add to the literature on the assessment of how well data simulated from new‐Keynesian dynamic stochastic general equilibrium (DSGE) models reproduce the dynamic features of historical data. In particular, we evaluate sticky price, sticky price with dynamic indexation, and sticky information models using impulse response and correlation measures and via implementation of a distribution based approach for comparing (possibly) misspecified DSGE models using simulated and historical inflation and output gap data. One of our main findings is that for a standard level of stickiness (i.e., annual price or information adjustment), the sticky price model with indexation dominates other models. We also find that when a lower level of information and price stickiness is used (i.e., bi‐annual adjustment), there is much less to choose between the models (see Bils and Klenow 2004, for evidence in favor of lower levels of stickiness). This finding is due to the fact that simulated and historical densities are “much” closer under bi‐annual adjustment.
Technology Shocks and the Labor‐Input Response: Evidence from Firm‐Level Data
Authors: CARLSSON MIKAEL , SMEDSAAS JON
Published: September 2007

We study the relationship between technology shocks and labor input on Swedish firm‐level data using a production function approach to identify technology shocks. Taking standard steps yields a contractionary contemporaneous labor‐input response in line with previous studies. This finding may, however, be driven by measurement errors in the labor‐input variable. Relying on a unique feature of our data set, which contains two independently measured firm‐specific labor input measures, we can evaluate the potential bias. We do not find that this bias conceals any true positive contemporaneous effect. The results thus point away from standard flexible‐price models and toward models emphasizing firm‐level rigidities.
On the Relationship between Inflation Persistence and Temporal Aggregation
Authors: PAYA IVAN , DUARTE AGUSTIN , HOLDEN KEN
Published: September 2007

This paper examines the impact of temporal aggregation on alternative definitions of inflation persistence. Using the CPI and the core PCE deflator of the United States, our results show that temporal aggregation from the monthly to the quarterly to the annual frequency induces persistence in the inflation series.
On Densification of Porous Materials Using Precursor Solutions
Authors: Mogilevsky Pavel , Kerans Ronald J. , Lee Hee Dong , Keller Kristin A. , Parthasarathy Triplicane A.
Published: September 2007

A quantitative model describing the densification of porous compacts using liquid solutions that takes into account the gradual sealing‐off of the porosity has been proposed. The model was applied to experimental data on densification of alumina compacts and alumina fiber‐reinforced ceramic composites infiltrated by an aqueous CrO3 solution. The results obtained with the present model were in good agreement with those expected based on the statistical models and computer simulations of the packing of spheres. Recommendations to improve the efficiency of the densification of porous materials using precursor solutions are suggested based on the results of the present work.
Effect of Zn/Si Ratio on the Microstructural and Microwave Dielectric Properties of Zn2SiO4 Ceramics
Authors: Nguyen Ngoc‐Huan , Lim Jong‐Bong , Nahm Sahn , Paik Jong‐Hoo , Kim Jong‐Hee
Published: September 2007

Zn2SiO4 ceramics synthesized by the conventional solid‐state method exhibited a low Q×f value, possibly due to the formation of a ZnO second phase. However, with a small ZnO reduction from the Zn2SiO4 ceramics, the ZnO second phase disappeared and grain growth occurred due to the formation of a Si‐rich liquid phase. Specimens with a large grain size exhibited an improved Q×f value. In particular, the ceramics with nominal composition Zn1.8SiO3.8 sintered at 1300°C exhibited improved microwave dielectric properties of ɛr=6.6, Q×f=147 000 GHz, and τf=−22 ppm/°C.
Synthesis of Nanocrystalline Chromium Nitride Powder by Mechanical Processing
Authors: Real Concepción , Roldán Manuel A. , Alcalá María D. , Ortega Andrés
Published: September 2007

The transition metal nitrides such as chromium nitride (CrN) show interesting properties that make them suitable for many technological uses. In the present work, pure nanocrystalline CrN has been directly prepared by mechanical alloying, from chromium metal under a pressurized nitrogen atmosphere, in a short milling time and without post‐heating treatment. The characterization of the final product by X‐ray diffraction, scanning electron microscopy, electron energy loss, and X‐ray photoelectron spectroscopy is presented.
In Situ Study of the Reaction Sequence in the Sol–Gel Synthesis of a (Ba0.5Sr0.5)(Co0.8Fe0.2)O3−δ Perovskite by X‐Ray Diffraction and Transmission Electron Microscopy
Authors: Arnold Mirko , Wang Haihui , Martynczuk Julia , Feldhoff Armin
Published: September 2007

Examination of the complexing citric acid/EDTA synthesis of (Ba0.5Sr0.5)(Co0.8Fe0.2)O3−δ is presented by in situ X‐ray diffraction and transmission electron microscopy, which elucidate all intermediate phases and the formation of the perovskite structure for the first time.
Homogeneous WC–Co‐Cemented Carbides from a Cobalt‐Coated WC Powder Produced by a Novel Solution‐Chemical Route
Authors: Ekstrand Åsa , Westin Gunnar , Nygren Mats
Published: September 2007

A solution chemical route to cobalt‐coated WC‐powder is described that allows for the preparation of WC–Co powders and compacts having a carbon content very close to the desired carbon content even under an inert atmosphere. The microstructural homogeneity in the sintered WC–Co composites when using the Co‐coated grains was found to be superior as compared with conventionally mill‐mixed powders, and the structural changes in the individual WC‐grains were found to be much smaller, which is ascribed mainly to the fact that the coated grains do not require a grinding step leading to the formation of a tail of smaller WC grain sizes.
Ceramics with Special Porous Structures Fabricated by Freeze‐Gelcasting: Using tert‐Butyl Alcohol as a Template
Authors: Chen Ruifeng , Wang Chang‐An , Huang Yong , Ma Liguo , Lin Weiyuan
Published: September 2007

By a novel freeze‐gelcasting technique, ceramic bodies with unidirectional ordered and gradient porous structures were fabricated, using tert‐butyl alcohol (TBA)/acrylamide (AM)/alumina (Al2O3) slurries. TBA, which can freeze below 25 °C and volatilize rapidly above 30 °C, was used as a template for forming pores. The porous structures could be controlled by the temperature conditions, resulting in special unidirectional and gradient porous structures over a long range of several millimeters. At the same time, gelation of AM was successfully introduced in this process, and played an important role in strengthening the green bodies (with compression strength over 10 MPa). Sintered Al2O3 with a high porosity showed high compression mechanical properties, which contributed to the high density of ceramic walls. This technique combines the two processes of cold freezing and thermal gelation in one procedure, and is considered to be potentially useful in many applications.
Listening to Reporters or Engineers? How Instance‐Based Messages About Building Design Affect Earthquake Fatalism1
Authors: McClure John , Sutton Robbie M. , Sibley Chris G.
Published: September 2007

Attributions are shaped by information about the causal mechanisms that produce outcomes. Two studies examined the effect of mechanism information on attributions for earthquake damage and judgments that the damage could be prevented. Scenarios based on actual reports of earthquakes compared 2 messages about the building design of damaged buildings. Accurate rate‐based messages stated that well‐designed buildings were resilient, whereas fatalistic, instance‐based messages stated that well‐designed buildings were damaged. In Study 2, to vary source credibility, the message source was either an engineer or a reporter. Participants made less fatalistic inferences and attributions with rate‐based messages than with instance‐based messages, regardless of the source. These findings show that rate‐based messages are likely to reduce fatalism about earthquakes and other risks.
Ethnicity‐Related Stressors and Mental Health in Latino Americans: The Moderating Role of Parental Racial Socialization
Authors: Chávez Noé Rubén , French Sabine Elizabeth
Published: September 2007

The current study examined the moderating role of proactive and reactive parental racial socialization on the relationship between Latino American college students' mental health and 3 ethnicity‐related stressors: perceived racial discrimination, stereotype confirmation concern, and own‐group conformity pressure. In hierarchical regression, greater stereotype confirmation concern predicted more mental distress in 105 Latino American college students. Both proactive and reactive racial socialization moderated the effect of own‐group conformity pressure on anxiety and loss of behavioral/emotional control. Specifically, greater proactive and reactive racial socialization predicted more mental distress under greater own‐group conformity pressure. Findings are interpreted in a college environment of ethnic diversity and a context of acculturative stress.
The Effect of Compliments on Tipping Behavior in Hairstyling Salons1
Authors: Seiter John S. , Dutson Eric
Published: September 2007

This study examined the role of compliments on tipping behavior in hairstyling salons. Two female hair stylists cut and styled 115 customers' hair and either complimented or did not compliment the customers while interacting. Results indicated that hair stylists received significantly higher tips when complimenting their customers than when not complimenting them. These results and their implications are discussed.
Gender Differences in Cardiovascular Reactivity and Game Performance Related to Sensory Modality in Violent Video Game Play1
Authors: Tafalla Richard J.
Published: September 2007

This study examined the gender‐specific cardiovascular and performance responses to playing the violent video game “DOOM” with and without the soundtrack. Men and women equally rated the game as more violent with the soundtrack. Men performed the game about twice as well with the soundtrack. Women's performance did not change at all. Only men's heart rates were significantly greater with the soundtrack, indicative of arousal. Only women's systolic and diastolic blood pressures were significantly greater with the soundtrack, indicative of stress. The game seemed to appeal more to men than to women. Moreover, women may possibly avoid violent video games, in part because they represent an undesirable stressor.
Social Influences on Organizational Attractiveness: Investigating If and When Word of Mouth Matters1
Authors: Van Hoye Greet , Lievens Filip
Published: September 2007

Previous recruitment studies have treated potential applicants as individual decision makers, neglecting informational social influences on organizational attractiveness. The present study investigated if and under what conditions word‐of‐mouth communication matters as a recruitment source. Results (N = 171) indicated that word of mouth had a strong impact on organizational attractiveness, and negative word of mouth interfered with recruitment advertising effects. Word of mouth from a strong tie was perceived as more credible and had a more positive effect on organizational attractiveness. For potential applicants high in self‐monitoring, word of mouth had a stronger effect when presented after recruitment advertising. Finally, the effect of word of mouth on organizational attractiveness was partially mediated by the perceived credibility of recruitment advertising.
The Effect of Acceptance/Rejection Status, Status Notification, and Organizational Obligation Fulfillment on Applicant Intentions
Authors: Waung Marie , Brice Thomas S.
Published: September 2007

Reactions to receiving or failing to receive rejection/acceptance letters were examined from the perspective of psychological contracts. In Study 1, a laboratory experiment, organizational obligation fulfillment was predicted by status (rejection/acceptance) and notification (no notification; notification only; notification plus explanation) such that those rejected without notification reported the lowest level of organizational obligation fulfillment. In Study 2, a field survey, applicants who were rejected with no rejection communication were more likely to believe that the organization failed to fulfill its obligations, and reported more negative intentions toward the organization compared to those who received a rejection communication. In both studies, organizational obligation fulfillment accounted for incremental variance in applicant intentions, beyond that of applicant status and type of rejection notification.
The Pique Technique: Overcoming Mindlessness or Shifting Heuristics?
Authors: Burger Jerry M. , Hornisher Joy , Martin Valerie E. , Newman Gary , Pringle Summer
Published: September 2007

An unusual request can increase compliance in situations in which the typical response to the request is refusal. This procedure, called the pique technique, is said to be effective because the unusual request causes people to give mindful consideration to it. We tested this explanation in 2 studies. Passersby were asked for either a common amount of change or 37 cents. Participants who inquired about the unusual amount were given either a specific or an uninformative reason. The pique technique increased compliance, but only when participants stopped to ask about the request. These participants gave more money, regardless of the reason provided. The findings failed to support the notion that an unusual request leads to a mindful consideration of it.
Structural Comparison of Cognitive Associative Networks in Two Populations1
Authors: Coronges Kathryn A. , Stacy Alan W. , Valente Thomas W.
Published: September 2007

The cognitive associative structure of 2 populations was studied using network analysis of free‐word associations. Structural differences in the associative networks were compared using measures of network centralization, size, density, clustering, and path length. These measures are closely aligned with cognitive theories describing the organization of knowledge and retrieval of concepts from memory. Size and centralization of semantic structures were larger for college students than for 7th graders, while density, clustering, and mean path length were similar. Findings presented reveal that subpopulations might have very different cognitive associative networks. This study suggests that graph theory and network analysis methods are useful in mapping differences in associative structures across groups.
Self‐Construal and Concerns Elicited by Imagined and Real Health Problems1
Authors: Uskul Ayse K. , Hynie Michaela
Published: September 2007

In 2 studies, we examined the relationship between self‐construal and illness‐related concerns. In Study 1, participants imagined themselves experiencing a health problem described in a scenario and answered closed‐ended questions about the concerns that this situation would likely elicit. The experience of social illness concerns was predicted by collective self‐construal, and the experience of personal illness concerns tended to be predicted by endorsement of individual self‐construal. In Study 2, participants recalled a past health problem and related consequences, which were content‐coded. Collective self‐construal predicted the extent to which people mentioned issues related to others in their free‐recall illness descriptions and the number of other‐related consequences that were generated when specifically asked about them.
Development of a positive preference–performance relationship in an oligophagous beetle: adaptive learning?
Authors: Xue Huai‐Jun , Egas Martijn , Yang Xing‐Ke
Published: September 2007

The relationship between oviposition preference and larval performance is a central topic in insect–plant biology. In this study, we investigate whether the oligophagous flea beetle, Altica fragariae Nakane (Coleoptera: Chrysomelidae), exhibits a positive preference–performance relationship, and whether oviposition preference develops over time. We tested the beetles using four sympatric plant species: Duchesnea indica (Andrews) Focke (the normal host plant), Agrimonia pilosa Ledeb. (a secondary host plant), and Potentilla chinensis Ser. and Sanguisorba officinalis L. (host plants of two related Altica species) (all Rosaceae). In no‐choice experiments, both oviposition rate and offspring fitness parameters (eclosion rate, development time, and body mass) were highest on D. indica. Oviposition rate was much lower on P. chinensis than on A. pilosa, whereas offspring fitness parameters did not differ significantly between these two host plants. Offspring fitness were lowest for S. officinalis, and adult females refused to oviposit on this acceptable non‐host in a no‐choice situation. Repeated two‐choice experiments showed that the proportion of oviposition on one of the novel host plants decreased significantly over time when the alternative host plant was D. indica. In repeated two‐choice experiments using A. pilosa and P. chinensis, females mainly fed on A. pilosa but distributed their eggs equally over the two host plants, in accordance with the lack of difference in offspring fitness on those hosts. Together, these results showed that A. fragariae females develop a positive preference–performance relationship over time. We suggest that A. fragariae achieves this through adaptive learning of oviposition preference: not only does the female learn to discriminate among the host plants when there is a fitness difference for her offspring, but the female also fails to discriminate when there is no fitness difference.
Temporal variation in foraging activity and efficiency and the role of hitchhiking behaviour in the leaf‐cutting ant, Atta cephalotes
Authors: Yackulic Charles B. , Lewis Owen T.
Published: September 2007

Two phenomena are integral to the foraging behaviour of leaf‐cutting ants in the genus Atta: hitchhiking (where small ants ride on leaf fragments carried by larger workers) and rhythmic foraging (where foraging activity shows marked fluctuations over time). While parasitism by phorid flies has been implicated in eliciting both behaviours, recent research suggests fungal contaminants and the need to procure sap also play a key role in eliciting hitchhiking. For wild colonies of Atta cephalotes L. (Hymenoptera: Formicidae), we investigated the extent to which hitchhiking frequency varied in space and time and the foraging performance of day‐time and night‐time workers. Day‐time foragers were considerably smaller than nocturnal foragers, a trend previously described as a response to diurnal phorids. Despite their smaller size, day‐time foragers had higher foraging performance, perhaps as a consequence of decreased trail congestion. Larger leaf‐carriers were more likely to carry hitchhikers and hitchhiking frequency was higher at night, an observation that conflicts with the parasitoid defence hypothesis, but not with the leaf sap and fungal defence hypotheses. Hitchhikers constitute a major proportion (typically 12%) of the loads carried by workers, and have three times the effect of leaf fragment mass on forager velocity. However, they reduced energetic efficiency by only 2.6% and provisioning rate by 5.9%. Our results provide partial support for the parasitoid defence hypothesis, but suggest that both the risks of parasitism and the opportunity‐cost to foraging associated with carrying hitchhikers may be low.
Posttraumatic stress disorder as a risk factor for obesity among male military veterans
Authors: Vieweg W. V. R. , Julius D. A. , Bates J. , Quinn J. F. , Fernandez A. , Hasnain M. , Pandurangi A. K.
Published: September 2007

Objective:  Obesity is a significant public health problem in the United States, particularly among military veterans with multiple risk factors. Heretofore, posttraumatic stress disorder (PTSD) has not clearly been identified as a risk factor for this condition.

Method:  We accessed both a national and local database of PTSD veterans.

Results:  Body mass index (BMI) was greater (P < 0.0001) among male military veterans (n = 1819) with PTSD (29.28 ± 6.09 kg/m2) than those veterans (n = 44 959) without PTSD (27.61 ± 5.99 kg/m2) in a sample of randomly selected veterans from the national database. In the local database of male military veterans with PTSD, mean BMI was in the obese range (30.00 ± 5.65) and did not vary by decade of life (P = 0.242).

Conclusion:  Posttraumatic stress disorder may be a risk factor for overweight and obesity among male military veterans.
Mutual induction of noncollagenous bone proteins at the interface between epithelial cells and fibroblasts from human periodontal ligament
Authors: Shimonishi M. , Hatakeyama J. , Sasano Y. , Takahashi N. , Komatsu M. , Kikuchi M.
Published: September 2007

Background and Objective:  Epithelial–mesenchymal interactions are responsible for cell differentiation during periodontal regeneration. The present study was undertaken to examine the expression of alkaline phosphatase and noncollagenous bone proteins, such as osteopontin, osteocalcin and bone sialoprotein, with respect to interaction between the cells of the epithelial rests of Malassez and fibroblasts from human periodontal ligament.

Material and Methods:  Explants of human periodontal ligament tissues produced outgrowths containing both putative epithelial rests of Malassez cells and human periodontal ligament fibroblasts in a modified serum‐free medium. Putative epithelial rests of Malassez cells cultured alone, and human periodontal ligament fibroblasts cultured alone, were used as controls. The expression levels of amelogenin were analyzed by in situ hybridization. The expression and distribution of alkaline phosphatase and noncollagenous bone proteins in both cell populations at the interface between putative epithelial rests of Malassez cells and human periodontal ligament fibroblasts were analyzed by immunohistochemistry, in situ hybridization and reverse transcription‐polymerase chain reaction.

Results:  Amelogenin mRNA was detected at high levels only in putative epithelial rests of Malassez cells at the interface. Alkaline phosphatase and bone sialoprotein mRNAs were detected significantly at the interface between putative epithelial rests of Malassez cells and human periodontal ligament fibroblast cells. In particular, bone sialoprotein and its mRNA were expressed significantly in human periodontal ligament fibroblasts at the interface between putative epithelial rests of Malassez cells and human periodontal ligament fibroblast cells. The expressions of osteopontin and its mRNA were not different between putative epithelial rests of malassez cells and human periodontal ligament fibroblasts at the interface. Osteocalcin and its mRNA were expressed strongly in putative epithelial rests of Malassez cells at the interface between putative epithelial rests of Malassez cells and human periodontal ligament fibroblasts.

Conclusion:  These findings indicate that the epithelial–mesenchymal interaction modulates the expression of alkaline phosphatase, osteocalcin and bone sialoprotein in putative epithelial rests of Malassez cells and human periodontal ligament fibroblasts, suggesting that epithelial–mesenchymal interactions play a role in the maintenance of periodontal ligament.
Human malarial parasite, Plasmodium falciparum, displays capacitative calcium entry: 2‐aminoethyl diphenylborinate blocks the signal transduction pathway of melatonin action on the P. falciparum cell cycle
Authors: Beraldo Flávio H. , Mikoshiba Katsuhiko , Garcia Célia R. S.
Published: September 2007

Abstract:  The malarial parasite senses the environment to modulate its own cycle. Knowledge of the mechanisms for regulation signaling processes at the invasion, maturation, as well as division of Plasmodium falciparum before reinvasion would represent a major breakthrough and, therefore, might open new avenues for therapy. We have previously reported that melatonin modulates the circadian rhythm of malarial parasites through the activation of phospholipase C (PLC), production of InsP3, and induction of calcium release from intracellular stores. To further investigate the molecular mechanism of melatonin’s action, we have used the InsP3 modulator 2‐aminoethyl diphenylborinate (2‐APB) given in a culture of P. falciparum parasites. Here we show that the melatonin acts on Plasmodium cell cycle through InsP3 signaling as 2‐APB blocks melatonin’s effect on calcium release. The function of the InsP3 signaling can be regarded as an important event for parasite invasion and maturation process, since addition of the PLC inhibitor, U73122 into Plasmodium‐infected red blood cells impairs parasite invasion in vitro. By using 8BrcAMP, we also report here that Plasmodia displays a ‘capacitative calcium entry’ mechanism for amplification of calcium signals throughout the cytoplasm.
Possible therapeutic value of melatonin in mild cognitive impairment: a retrospective study
Authors: Furio Analía M. , Brusco Luis I. , Cardinali D. P.
Published: September 2007

Abstract:  Mild cognitive impairment (MCI) is an etiologically heterogeneous syndrome characterized by cognitive impairment preceding dementia. Approximately 12% of MCI patients convert to Alzheimer’s disease (AD) or other dementia disorders every year. In the present report we retrospectively examined the initial and final neuropsychological assessment of 50 MCI outpatients, 25 of whom had received daily 3–9 mg of a fast‐release melatonin preparation p.o. at bedtime for 9–18 months. Melatonin was given in addition to the standard medication prescribed by the attending psychiatrist. Patients treated with melatonin showed significantly better performance in Mini Mental State Examination and the cognitive subscale of the Alzheimer’s Disease Assessment Scale. After application of a battery of neuropsychological tests including Mattis’ test, Digit‐symbol test, Trail A and B tasks and the Rey’s verbal test, better performance was found in melatonin‐treated patients, except for the Digit‐symbol test score which remained unchanged. Abnormally high Beck Depression Inventory scores decreased in melatonin‐treated patients, concomitantly with an improvement in wakefulness and sleep quality. The results suggest that melatonin can be a useful add‐on drug for treating MCI in a clinical setting.
Two Human ARFGAPs Associated with COP‐I‐Coated Vesicles
Authors: Frigerio Gabriella , Grimsey Neil , Dale Martin , Majoul Irina , Duden Rainer
Published: September 2007

ADP‐ribosylation factors (ARFs) are critical regulators of vesicular trafficking pathways and act at multiple intracellular sites. ADP‐ribosylation factor‐GTPase‐activating proteins (ARFGAPs) are proposed to contribute to site‐specific regulation. In yeast, two distinct proteins, Glo3p and Gcs1p, together provide overlapping, essential ARFGAP function required for coat protein (COP)‐I‐dependent trafficking. In mammalian cells, only the Gcs1p orthologue, named ARFGAP1, has been characterized in detail. However, Glo3p is known to make the stronger contribution to COP I traffic in yeast. Here, based on a conserved signature motif close to the carboxy terminus, we identify ARFGAP2 and ARFGAP3 as the human orthologues of yeast Glo3p. By immunofluorescence (IF), ARFGAP2 and ARFGAP3 are closely colocalized with coatomer subunits in NRK cells in the Golgi complex and peripheral punctate structures. In contrast to ARFGAP1, both ARFGAP2 and ARFGAP3 are associated with COP‐I‐coated vesicles generated from Golgi membranes in the presence of GTP‐γ‐S in vitro. ARFGAP2 lacking its zinc finger domain directly binds to coatomer. Expression of this truncated mutant (ΔN‐ARFGAP2) inhibits COP‐I‐dependent Golgi‐to‐endoplasmic reticulum transport of cholera toxin (CTX‐K63) in vivo. Silencing of ARFGAP1 or a combination of ARFGAP2 and ARFGAP3 in HeLa cells does not decrease cell viability. However, silencing all three ARFGAPs causes cell death. Our data provide strong evidence that ARFGAP2 and ARFGAP3 function in COP I traffic.
Zinc‐binding property of the major yolk protein in the sea urchin − implications of its role as a zinc transporter for gametogenesis
Authors: Unuma Tatsuya , Ikeda Kazuo , Yamano Keisuke , Moriyama Akihiko , Ohta Hiromi
Published: September 2007

Major yolk protein (MYP), a transferrin superfamily protein that forms yolk granules in sea urchin eggs, is also contained in the coelomic fluid and nutritive phagocytes of the gonad in both sexes. MYP in the coelomic fluid (CFMYP; 180 kDa) has a higher molecular mass than MYP in eggs (EGMYP; 170 kDa). Here we show that MYP has a zinc‐binding capacity that is diminished concomitantly with its incorporation from the coelomic fluid into the gonad in the sea urchin Pseudocentrotus depressus. Most of the zinc in the coelomic fluid was bound to CFMYP, whereas zinc in eggs was scarcely bound to EGMYP. Both CFMYP and EGMYP were present in nutritive phagocytes, where CFMYP bound more zinc than EGMYP. Saturation binding assays revealed that CFMYP has more zinc‐binding sites than EGMYP. Labeled CFMYP injected into the coelom was incorporated into ovarian and testicular nutritive phagocytes and vitellogenic oocytes, and the molecular mass of part of the incorporated CFMYP shifted to 170 kDa. Considering the fact that the digestive tract is a major production site of MYP, we propose that CFMYP transports zinc, essential for gametogenesis, from the digestive tract to the ovary and testis through the coelomic fluid, after which part of the CFMYP is processed to EGMYP with loss of zinc‐binding site(s).
Protective Effects of Sasanquasaponin on Injury of Endothelial Cells Induced by Anoxia and Reoxygenation in vitro
Authors: Huang Qiren , He Ming , Chen Heping , Shao Lijian , Liu Dan , Luo Yongming , Dai Yucheng
Published: September 2007

Abstract:  The protective effects of sasanquasaponin, an effective compound from Chinese traditional herbs, on ischaemia and reperfusion injury in mouse hearts have been suggested through modulation of intracellular Cl− homeostasis. The effects of sasanquasaponin on injury of endothelial cells, however, induced by anoxia and reoxygenation remain unknown. Therefore, the present study attempted to observe the effects of sasanquasaponin on anoxia and reoxygenation injury in endothelial cells and investigate its putative mechanisms. Human umbilical vein endothelial cells (HUVECs) were exposed to normoxia or anoxia and reoxygenation in the absence or presence of sasanquasaponin (10.0, 1.0 and 0.1 µmol/l). Lactate dehydrogenase activity was determined in cultured HUVECs supernatant, and malondialdehyde content, superoxide dismutase and glutathione peroxidase activities were measured in HUVECs by a colorimetric method. Neutrophil adhesion to HUVECs was assayed colorimetrically. The levels of intercellular adhesion molecule‐1 and tumour necrosis factor‐α were detected. The activity of nuclear factor kappa B was determined by flow cytometry. The results show that sasanquasaponin decreased the lactate dehydrogenase activity and malondialdehyde contents, and inhibited the neutrophil adhesion to HUVECs; sasanquasaponin, moreover, inhibited nuclear factor kappa B transnuclear activity, lowered tumour necrosis factor‐α and intercellular adhesion molecule‐1 expression levels. On the other hand, sasanquasaponin increased the mitochondrial superoxide dismutase and glutathione peroxidase activities. It is suggested that sasanquasaponin could protect HUVECs against anoxia and reoxygenation injury, and the protective mechanisms appear to be related to anti‐lipoperoxidation and anti‐adhesion.