bluuebunny/crossref_metadata_2025_split huggingface dataset:
Use of three‐dimensional (3‐D) immersive virtual worlds in K‐12 and higher education settings: A review of the research
Authors: Hew Khe Foon , Cheung Wing Sum 
Published: October 2008

AbstractIn this paper, we review past empirical research studies on the use of three‐dimensional immersive virtual worlds in education settings such as K‐12 and higher education. Three questions guided our review: (1) How are virtual worlds (eg, Active Worlds, Second Life) used by students and teachers? (2) What types of research methods have been applied? (3) What research topics have been conducted on virtual worlds in teaching and learning, as well as their related findings? Overall, we found that virtual worlds may be utilised for the following uses: (1) communication spaces, (2) simulation of space (spatial), and (3) experiential spaces (‘acting’ on the world). Most of the studies reviewed were descriptive and conducted in polytechnic and university settings, and past virtual world research had been most frequently carried out in the media arts and health and environment disciplines. Three main research topics were found: participants' affective domain, learning outcomes and social interaction. We conclude by summarising some major findings and discussing three limitations of previous empirical studies. Several recommendations for future research related to virtual worlds in education settings are also provided.
Sure Independence Screening for Ultrahigh Dimensional Feature Space
Authors: Fan Jianqing , Lv Jinchi 
Published: October 2008

SummaryVariable selection plays an important role in high dimensional statistical modelling which nowadays appears in many areas and is key to various scientific discoveries. For problems of large scale or dimensionality p, accuracy of estimation and computational cost are two top concerns. Recently, Candes and Tao have proposed the Dantzig selector using L1-regularization and showed that it achieves the ideal risk up to a logarithmic factor log(p). Their innovative procedure and remarkable result are challenged when the dimensionality is ultrahigh as the factor log(p) can be large and their uniform uncertainty principle can fail. Motivated by these concerns, we introduce the concept of sure screening and propose a sure screening method that is based on correlation learning, called sure independence screening, to reduce dimensionality from high to a moderate scale that is below the sample size. In a fairly general asymptotic framework, correlation learning is shown to have the sure screening property for even exponentially growing dimensionality. As a methodological extension, iterative sure independence screening is also proposed to enhance its finite sample performance. With dimension reduced accurately from high to below sample size, variable selection can be improved on both speed and accuracy, and can then be accomplished by a well-developed method such as smoothly clipped absolute deviation, the Dantzig selector, lasso or adaptive lasso. The connections between these penalized least squares methods are also elucidated.
Pre‐synaptic GABAB receptors inhibit glutamate release through GIRK channels in rat cerebral cortex
Authors: Ladera Carolina , Del Carmen Godino María , Cabañero María José , Torres Magdalena , Watanabe Masahiko , Luján Rafael , Sánchez‐Prieto José 
Published: October 2008

AbstractNeuronal G protein‐gated inwardly rectifying potassium (GIRK) channels mediate the slow inhibitory effects of many neurotransmitters post‐synaptically. However, no evidence exists that supports that GIRK channels play any role in the inhibition of glutamate release by GABAB receptors. In this study, we show for the first time that GABAB receptors operate through two mechanisms in nerve terminals from the cerebral cortex. As shown previously, GABAB receptors reduces glutamate release and the Ca2+ influx mediated by N‐type Ca2+ channels in a mode insensitive to the GIRK channel blocker tertiapin‐Q and consistent with direct inhibition of this voltage‐gated Ca2+ channel. However, by means of weak stimulation protocols, we reveal that GABAB receptors also reduce glutamate release mediated by P/Q‐type Ca2+ channels, and that these responses are reversed by the GIRK channel blocker tertiapin‐Q. Consistent with the functional interaction between GABAB receptors and GIRK channels at nerve terminals we demonstrate by immunogold electron immunohistochemistry that pre‐synaptic boutons of asymmetric synapses co‐express GABAB receptors and GIRK channels, thus suggesting that the functional interaction of these two proteins, found at the post‐synaptic level, also occurs at glutamatergic nerve terminals.
Comparing Cost‐of‐Illness Estimates from Alternative Approaches: An Application to Diabetes
Authors: Honeycutt Amanda A. , Segel Joel E. , Hoerger Thomas J. , Finkelstein Eric A. 
Published: October 2008

Objective. To compare disease cost estimates from two commonly used approaches.Data Source. Pooled Medical Expenditure Panel Survey (MEPS) data for 1998–2003.Study Design. We compared regression‐based (RB) and attributable fraction (AF) approaches for estimating disease‐attributable costs with an application to diabetes. The RB approach used results from econometric models of disease costs, while the AF approach used epidemiologic formulas for diabetes‐attributable fractions combined with the total costs for seven conditions that result from diabetes.Data Extraction. We used SAS version 9.1 to create a dataset that combined data from six consecutive years of MEPS.Principal Findings. The RB approach produced higher estimates of diabetes‐attributable medical spending ($52.9 billion in 2004 dollars) than the AF approach ($37.1 billion in 2004 dollars). RB model estimates may in part be higher because of the challenges of implementing the two approaches in a similar manner, but may also be higher because they capture the costs of increased treatment intensity for those with the disease.Conclusions. We recommend using the RB approach for estimating disease costs whenever individual‐level data on health care spending are available and when the presence of the disease affects treatment costs for other conditions, as in the case of diabetes.
Sodium, hypertension, and an explanation of the “lag phenomenon” in hemodialysis patients
Authors: TWARDOWSKI Zbylut J. 
Published: October 2008

AbstractSodium balance is precisely regulated by intake and output. The kidneys are responsible for adjusting sodium excretion to maintain balance at varying intakes. Our distant ancestors were herbivores. Their diet contained little sodium, so they developed powerful mechanisms for conserving sodium and achieving low urinary excretion. About 10,000 years ago, early humans became villagers and discovered that food could be preserved in brine. This led to increased consumption of salt. High salt intake increases extracellular volume (ECV), blood volume, and cardiac output resulting in elevation of blood pressure. High ECV induces release of a digitalis‐like immunoreactive substance and other inhibitors of Na+‐K+‐ATPase. As a consequence, intracellular sodium and calcium concentrations increase in vascular smooth muscles predisposing them to contraction. Moreover, high ECV increases synthesis and decreases clearance of asymmetrical dimethyl‐l‐arginine leading to inhibition of nitric oxide (NO) synthase. High concentration of sodium and calcium in vascular smooth muscles, and decreased synthesis of NO lead to an increase in total peripheral resistance. Restoration of normal ECV and blood pressure are attained by increased glomerular filtration and decreased sodium reabsorption. In some individuals, the kidneys have difficulty in excreting sodium, so the equilibrium is achieved at the expense of elevated blood pressure. There is some lag time between reduction of ECV and normalization of blood pressure because the normal levels of Na+‐K+‐ATPase inhibitors and asymmetrical dimethyl‐l‐arginine are restored slowly. In dialysis patients, all mechanisms intended to increase renal sodium removal are futile but they still operate and elevate blood pressure. The sodium balance must be achieved via dialysis and ultrafiltration. Blood pressure is normalized a few weeks after ECV is returned to normal, i.e., when the patient reaches dry body weight. This is called the “lag phenomenon.”
Fatal cerebritis and brain abscesses following a nontraumatic subdural hematoma in a chronic hemodialyzed patient
Authors: MESQUITA Maria , DAMRY Nasroolla , GAZAGNES Marie D. 
Published: October 2008

Abstract Staphylococcus aureus is the leading cause of bacteremia in hemodialysis‐dependent patients that can lead to metastatic abscesses with poor outcome. We report a case of a 65‐year‐old chronic hemodialyzed male patient who developed cerebritis and brain abscesses complicating a spontaneous subdural hematoma, following Staphylococcus aureus bacteremia related to infected arteriovenous fistula. In spite of adequate antibiotherapy and several surgical brain drainages, our patient did not survive. Prevention of S. aureus is highly important in hemodialysis patients.
Heparin leak from a hemodialysis catheter causing major bleeding, ultimately leading to transplant rejection and death
Authors: DREYER Gavin , LAWTON Paul , JOSE Matthew 
Published: October 2008

AbstractLeakage of hemodialysis catheter‐locking solutions into the circulation has been reported in in vitro and in vivo studies, although there have been few reports of serious clinical adverse events. We describe a case of heparin leak from a hemodialysis catheter, which caused significant clinical bleeding requiring multiple transfusions and may have ultimately been responsible for the patient's death after transplantation.
Cultural comparison of symptoms in patients on maintenance hemodialysis
Authors: WEISBORD Steven D. , BOSSOLA Maurizio , FRIED Linda F. , GIUNGI Stefania , TAZZA Luigi , PALEVSKY Paul M. , ARNOLD Robert M. , LUCIANI Giovanna , KIMMEL Paul L. 
Published: October 2008

AbstractAlthough symptoms are common and frequently severe in patients on maintenance hemodialysis, little is known about the relationship between cultural background and symptom burden. The aim of this study was to explore differences in the prevalence and severity of symptoms between American and Italian hemodialysis patients. We administered the 30‐item Dialysis Symptom Index to American and Italian patients receiving maintenance hemodialysis during routine dialysis sessions. The prevalence and severity of individual symptoms were compared between patient populations, adjusting for multiple comparisons. Multivariable logistic regression and ordinal logistic regression were used to assess the independent associations of cultural background with the prevalence and severity of symptoms, respectively. We enrolled 75 American and 61 Italian patients. American patients were more likely to be black (36% vs. 0%, P<0.001) and diabetic (53% vs. 13%, P<0.001). Italian patients were more likely to report decreased interest in sex, decreased sexual arousal, feeling nervous, feeling irritable, and worrying (P<0.001, respectively). Adjustment for demographic and clinical variables had no impact on these cultural differences in symptom prevalence. The median severity of 11 symptoms including muscle soreness, muscle cramps, and itching was greater among Americans (P<0.001, respectively), although nearly all of these differences were rendered nonstatistically significant with adjustment for race, diabetes, and/or Kt/V. Italian patients receiving chronic hemodialysis report a greater burden of symptoms than American patients, particularly those related to sexual dysfunction and psychosocial distress. These findings suggest that cultural background may affect adaptation to chronic hemodialysis therapy.
Costs of managing anemia with erythropoiesis‐stimulating agents during hemodialysis: A time and motion study
Authors: SCHILLER Brigitte , DOSS Sheila , DE COCK Erwin , DEL AGUILA Michael A. , NISSENSON Allen R. 
Published: October 2008

AbstractUse of erythropoiesis‐stimulating agents (ESAs) presents a significant time and cost burden in the management of anemia of chronic kidney disease (CKD). We conducted a prospective, observational, activity‐based costing study to estimate the health care personnel time and resulting direct medical costs associated with administering epoetin 3 times weekly to patients with end‐stage renal disease on dialysis. The study was conducted at 5 US hemodialysis centers. The personnel time and costs were derived from time and motion observations. Predicted time and cost savings were modeled for switching patients to once‐monthly ESA therapy. Patients also completed a survey questionnaire to assess their level of CKD knowledge and information needs. Total per‐patient‐per‐year (PPPY) time expended on anemia management with epoetin averaged 608 minutes (range 512–915 minutes), with an average PPPY cost of $548 (range $342–$651). Use of a once‐monthly ESA, compared with epoetin, could decrease average PPPY time expenditure by 79% (127 minutes [range 96–173 minutes]) and reduce PPPY costs by 81% ($104 [range $79–$136]). The patient questionnaire reported insufficient education on CKD. Use of a once‐monthly ESA to correct anemia in dialysis patients may provide substantial time, resource, and cost savings compared with current treatment practices.
Correlates affecting survival in chronic hemodialysis patients: The combined impact of albumin and high hemoglobin levels on improving outcomes, local and national results
Authors: CAPELLI John P. , KUSHNER Harvey 
Published: October 2008

AbstractWhile national mortality rates for end‐stage renal disease (ESRD) patients remain high, for the past 4 years, lower than expected local mortality rates have been consistently seen in our facilities. Because of these progressive improvements in mortality rates, a study of 687 hemodialysis patients over a 4‐year period, 2003 through 2006, was undertaken to analyze which factors may be contributing to the enhanced survival rates. We also examined the partially overlapping United States Renal Data System clinical performance measures national data sets of hemodialysis patients for 2001 to 2004. Proportional hazards and logistic regression models were used to determine significant predictors of short‐term survival. Variables tested included hemoglobin (Hb), albumin, calcium, phosphorus, infections, hospitalizations, URR, Kt/V, erythropoietic stimulating agents (epoetin‐α) use, and comorbid conditions. The local and national models identified albumin, Hgb, and hospitalization as statistically significant predictors of survival. Local models also found years of dialysis as a significant predictor. Locally, there was a 69‐fold increase from 16.1 deaths/1000 patient years for albumin ≥4.0 with Hgb≥14.0 to 1115.9 deaths/1000 patient‐years for albumin <3.5 with Hgb<11.0. The increase nationally is a 4‐fold increase from 96 deaths/1000 patient‐years for albumin ≥4.0 with Hgb≥14.0 to 406 deaths/1000 patient‐years for albumin <3.5 with Hgb<11.0. There was no evidence that higher erythropoietic stimulating agents dose levels were associated with higher mortality rates, independent of the other significant factors. In conclusion, the findings indicate that individually higher Hgb and albumin levels are associated with increased survival, and when higher Hgb levels are in association with high albumin levels, the survival rates and hospitalizations are synergistically improved.
Infective spondylodiscitis in patients on high‐flux hemodialysis and on‐line hemodiafiltration
Authors: ABID Saima , DE SILVA Shamila , WARWICKER Paul , FARRINGTON Ken 
Published: October 2008

AbstractInfective spondylodiscitis (ISD) is a rare but potentially devastating condition in hemodialysis (HD) patients. Reports are limited especially in patients receiving high‐flux HD and hemodiafiltration (HDF). In a retrospective analysis, 13 patients on our maintenance high‐flux HD/HDF program were identified as having has infective spondylodiscitis over a 10‐year period (1997–2006), an incidence of approximately 1 episode every 215 patient‐years. The incidence was around 3 times higher in patients dialyzing with tunnelled central venous catheters (TCVC) than in those with arteriovenous fistulae. Affected patients were elderly (mean age 70 years) and had multiple comorbidities. Access problems, particularly TCVC infection, were common in the months preceding it's onset. Tunnelled central venous catheter removal during these episodes did not necessarily prevent it. Diagnosis was based on a history of back pain, raised C‐reactive protein, positive blood cultures, and characteristic magnetic resonance findings. Many patients were apyrexial and had normal white cell counts. In our patients on high‐flux HD/hemodiafiltration, its incidence appears comparable to that in conventional HD settings. No patients had infection with waterborne organisms. Blood cultures were positive in 77%. Gram‐positive organisms predominated, particularly Staphylococcus aureus. The major route of infection was hematogenous, with the most likely source the venous access. All received antibiotics for 6 to 12 weeks or until death. Only 2 patients underwent surgical drainage. Mortality was high (46%) and predicted by the development of complications, and by pre‐existing cardiovascular comorbidity. Prevention, using strategies to reduce the prevalence of bacteremia, including limiting the use of TCVC, should be an overriding aim.
Paraoxonase‐1 (PON1) activity as a risk factor for atherosclerosis in chronic renal failure patients
Authors: SAEED Saeed Abdelwhab , ELSHARKAWY Magdy , ELSAEED Kadry , FOODA Osman 
Published: October 2008

AbstractParaoxonase is a high‐density lipoprotein‐associated enzyme and has been shown to reduce the susceptibility to low‐density lipoprotein peroxidation. This study aimed to investigate the activity of serum paraoxonase in uremic patients on hemodialysis (HD) and in the predialysis period, and to evaluate the correlations of vascular disease with paraoxonase activity. Thirty patients with chronic renal failure (CRF) undergoing HD (group 1), 30 patients with CRF under conservative treatment (group 2), and 30 healthy controls (group 3) were included. Basal, salt‐stimulated, and arylesterase activity were tested by UV spectrophotometry. Serum lipid parameters were determined. B‐Mode Doppler ultrasound was used to assess common carotid intima‐media thickness (IMT). Basal paraoxonase, salt‐stimulated, and arylesterase activity showed no significant difference between group 1 and group 2. However, it was significantly lower in group 1 and in group 2 than controls. Carotid IMT was significantly higher in group 1 than group 2 and both were significantly higher than controls. Basal paraoxonase‐1 (PON1), salt‐stimulated PON1, and arylesterase activity correlate with BUN, but only basal PON1 and salt‐stimulated PON1 correlate with serum albumin. Linear regression showed that the most significant determinant of carotid IMT was PON1 arylesterase activity in group 1 and arylesterase activity and basal PON1 activity in group 2. Patients with CRF, whether under HD or conservative treatment, have reduced basal and stimulated paraoxonase activities, and this could be an important factor causing increased vascular disease in those patients. Modifying this factor can be of great value to protect against this common complication.
Linking Centers for Medicare & Medicaid Services data with prospective DCOR trial data: Methods and data comparison results
Authors: St. PETER Wendy L. , LIU Jiannong , WEINHANDL Eric D. , FAN Qiao 
Published: October 2008

AbstractThe Dialysis Clinical Outcomes Revisited (DCOR) trial was a large randomized, multicenter 3‐year trial comparing the effects of sevelamer with calcium‐based binders on mortality, hospitalization, morbidity, and medical costs in hemodialysis subjects. Dialysis Clinical Outcomes Revisited was prospectively designed to link subjects to the Centers for Medicare & Medicaid Services End‐Stage Renal Disease (CMS ESRD) database to collect additional baseline characteristic data and to enhance outcome evaluation. Subjects were linked to the CMS ESRD database by means of an algorithm using several patient identifiers. Some baseline characteristic data were collected exclusively from the CMS ESRD database. Mortality and hospitalization end points were obtained from the CMS ESRD database and compared with similar data collected prospectively into a case‐report form (CRF) database. Of the 2103 patients who participated in the DCOR study, 2101 were successfully linked to the CMS ESRD database. Patient baseline data showed that treatment groups were well‐balanced, except that a higher proportion of subjects in the calcium‐based binder group had atherosclerotic heart disease. Calculated mortality rates were similar between databases, but more deaths were identified in the CMS than in the CRF database. These additional deaths were verified through several sources. More hospitalizations were also detected in the CMS than in the CRF database. The CMS database was a good source of death end points and hospitalization occurrence. Linking patients to the data‐rich CMS ESRD database allowed assessment of additional important secondary end points at a relatively low cost compared with prospective data collection.
Calponin control of cerebrovascular reactivity: therapeutic implications in brain trauma
Authors: Kreipke Christian W. , Rafols Jose A. 
Published: October 2008

A role for Calponin (Cp) in mediating smooth muscle (SM) contraction
Cp phosphorylation and vascular contractility
Cp localization and function in the brain
Does Cp play a role in pathologic states?
Cp and TBI
Endothelin (ET)‐1, its receptors (ETrA, ETrB) and Cp‐mediated vasoreactivity: Therapeutic implications
Conclusion

AbstractCalponin (Cp) is an actin‐binding protein first characterized in chicken gizzard smooth muscle (SM). This review discusses the role of Cp in mediating SM contraction, the biochemical process by which Cp facilitates SM contraction and the function of Cp in the brain. Recent work on the role of Cp in pathological states with emphasis on traumatic brain injury is also discussed. Based on past and present data, the case is presented for targeting Cp for novel genetic and pharmacological therapies aimed at improving outcome following traumatic brain injury (TBI).
Women and Shakespeare in the Restoration and Eighteenth Century
Authors: Ritchie Fiona 
Published: October 2008

AbstractThis article examines the role of gender in the popularisation of Shakespeare in the long eighteenth century, providing an overview of scholarship on three groups of women: actresses (the first women on the stage and later performers such as Catherine Clive, Susannah Cibber and Hannah Pritchard), women in the theatre audience (including Elizabeth Pepys and the Shakespeare Ladies Club) and female critics (notably Charlotte Lennox and Elizabeth Montagu). In addition to suggesting further reading on the topic of women and Shakespeare and highlighting directions for subsequent research, the essay demonstrates that women were instrumental in shaping the Bard's reputation in the period from the reopening of the theatres in 1660 to David Garrick's Shakespeare Jubilee of 1769, the height of the period's adulation of Shakespeare.
Representations of the Devil in Fin‐de‐Siècle Literature
Authors: White Lizzie 
Published: October 2008

AbstractThis article makes the case for a critical consideration of representations of the devil in fin‐de‐siècle literature. Surveying the field of critical material relating to representations of the devil, it argues that texts from the fin de siècle receive little attention. In addition, it suggests that discussion of religious issues is often quite limited in critical treatments of fin‐de‐siècle writers. By using six texts published between 1880 and 1920 as examples, it encourages a reconsideration of the literature of the period in relation to the religious controversies of the mid‐nineteenth century.