Showing papers by "University of Alabama published in 2002"

Dissolution of Cellose with Ionic Liquids

Abstract: We report here initial results that demonstrate that cellulose can be dissolved without activation or pretreatment in, and regenerated from, 1-butyl-3-methylimidazolium chloride and other hydrophilic ionic liquids. This may enable the application of ionic liquids as alternatives to environmentally undesirable solvents currently used for dissolution of this important bioresource.

Introduction to Linear Regression Analysis

Abstract: (2002). Introduction to Linear Regression Analysis. Technometrics: Vol. 44, No. 2, pp. 191-192.

Dual-chamber pacing or ventricular backup pacing in patients with an implantable defibrillator: the Dual Chamber and VVI Implantable Defibrillator (DAVID) Trial.

Abstract: CONTEXT: Implantable cardioverter defibrillator (ICD) therapy with backup ventricular pacing increases survival in patients with life-threatening ventricular arrhythmias. Most currently implanted ICD devices provide dual-chamber pacing therapy. The most common comorbid cause for mortality in this population is congestive heart failure. OBJECTIVE: To determine the efficacy of dual-chamber pacing compared with backup ventricular pacing in patients with standard indications for ICD implantation but without indications for antibradycardia pacing. DESIGN: The Dual Chamber and VVI Implantable Defibrillator (DAVID) Trial, a single-blind, parallel-group, randomized clinical trial. SETTING AND PARTICIPANTS: A total of 506 patients with indications for ICD therapy were enrolled between October 2000 and September 2002 at 37 US centers. All patients had a left ventricular ejection fraction (LVEF) of 40% or less, no indication for antibradycardia pacemaker therapy, and no persistent atrial arrhythmias. INTERVENTIONS: All patients had an ICD with dual-chamber, rate-responsive pacing capability implanted. Patients were randomly assigned to have the ICDs programmed to ventricular backup pacing at 40/min (VVI-40; n = 256) or dual-chamber rate-responsive pacing at 70/min (DDDR-70; n = 250). Maximal tolerated medical therapy for left ventricular dysfunction, including angiotensin-converting enzyme inhibitors and beta-blockers, was prescribed to all patients. MAIN OUTCOME MEASURE: Composite end point of time to death or first hospitalization for congestive heart failure. RESULTS: One-year survival free of the composite end point was 83.9% for patients treated with VVI-40 compared with 73.3% for patients treated with DDDR-70 (relative hazard, 1.61; 95% confidence interval [CI], 1.06-2.44). The components of the composite end point, mortality of 6.5% for VVI-40 vs 10.1% for DDDR-70 (relative hazard, 1.61; 95% CI, 0.84-3.09) and hospitalization for congestive heart failure of 13.3% for VVI-40 vs 22.6% for DDDR-70 (relative hazard, 1.54; 95% CI, 0.97-2.46), also trended in favor of VVI-40 programming. CONCLUSION: For patients with standard indications for ICD therapy, no indication for cardiac pacing, and an LVEF of 40% or less, dual-chamber pacing offers no clinical advantage over ventricular backup pacing and may be detrimental by increasing the combined end point of death or hospitalization for heart failure.

Effect of Dialysis Dose and Membrane Flux in Maintenance Hemodialysis

Abstract: Background The effects of the dose of dialysis and the level of flux of the dialyzer membrane on mortality and morbidity among patients undergoing maintenance hemodialysis are uncertain. Methods We undertook a randomized clinical trial in 1846 patients undergoing thrice-weekly dialysis, using a two-by-two factorial design to assign patients randomly to a standard or high dose of dialysis and to a low-flux or high-flux dialyzer. Results In the standard-dose group, the mean (±SD) urea-reduction ratio was 66.3±2.5 percent, the single-pool Kt/V was 1.32±0.09, and the equilibrated Kt/V was 1.16±0.08; in the high-dose group, the values were 75.2±2.5 percent, 1.71±0.11, and 1.53±0.09, respectively. Flux, estimated on the basis of beta2-microglobulin clearance, was 3±7 ml per minute in the low-flux group and 34±11 ml per minute in the high-flux group. The primary outcome, death from any cause, was not significantly influenced by the dose or flux assignment: the relative risk of death in the high-dose group as com...

Antiretroviral-Drug Resistance among Patients Recently Infected with HIV

Abstract: Background Among persons in North America who are newly infected with the human immunodeficiency virus (HIV), the prevalence of transmitted resistance to antiretroviral drugs has been estimated at 1 to 11 percent. Methods We performed a retrospective analysis of susceptibility to antiretroviral drugs before treatment and drug-resistance mutations in HIV in plasma samples from 377 subjects with primary HIV infection who had not yet received treatment and who were identified between May 1995 and June 2000 in 10 North American cities. Responses to treatment could be evaluated in 202 subjects. Results Over the five-year period, the frequency of transmitted drug resistance increased significantly. The frequency of high-level resistance to one or more drugs (indicated by a value of more than 10 for the ratio of the 50 percent inhibitory concentration [IC50] for the subject's virus to the IC50 for a drug-sensitive reference virus) increased from 3.4 percent during the period from 1995 to 1998 to 12.4 percent dur...

Assessing the psychometric properties of the entrepreneurial orientation scale: a multi-country analysis

Abstract: This study utilized data from 1,067 firms In six countries to clarify the psychometric properties of the entrepreneurial orientation (EO) measure. The first research question addressed dimensionali...

Changes in pathogens causing early-onset sepsis in very-low-birth-weight infants.

Abstract: Background It is uncertain whether the rates and causes of early-onset sepsis (that occurring within 72 hours after birth) among very-low-birth-weight infants have changed in recent years, since antibiotics have begun to be used more widely during labor and delivery. Methods We studied 5447 very-low-birth-weight infants (those weighing between 401 and 1500 g) born at centers of the Neonatal Research Network of the National Institute of Child Health and Human Development between 1998 and 2000 who had at least one blood culture in the first three days of life and compared them with 7606 very-low-birth-weight infants born at centers in the network between 1991 and 1993. Results Early-onset sepsis (as confirmed by positive blood cultures) was present in 84 infants in the more recent birth cohort (1.5 percent). As compared with the earlier birth cohort, there was a marked reduction in group B streptococcal sepsis (from 5.9 to 1.7 per 1000 live births of infants weighing 401 to 1500 g, P<0.001) and an increase ...

Crafting a change message to create transformational readiness

Abstract: Explains how we used the change message components of discrepancy, appropriateness, efficacy, principal support, and personal valence and the message conveying strategies of active participation, persuasive communication and management of information suggested by Armenakis and colleagues to help an organization create readiness for a major reorganization. We describe and evaluate our experiences from our initial coaching with the president, through initial management meetings to determine the new business unit’s strategy and structure, to the initial company‐wide announcement of the plans. We conclude with a set of observations and lessons and suggestions for future research on the use of the change message framework.

A controlled trial of rasagiline in early Parkinson disease: The tempo study

Abstract: CONTEXT Monotherapy with rasagiline mesylate may be useful in early Parkinson disease (PD). OBJECTIVE To evaluate the safety and efficacy of the selective monoamine oxidase type B inhibitor rasagiline. DESIGN Multicenter, 26-week, parallel-group, randomized, double-blind, placebo-controlled clinical trial. SETTING Academically based movement disorders clinics. PATIENTS Patients with early PD not requiring dopaminergic therapy (n = 404). INTERVENTION Research participants were randomized to rasagiline mesylate at dosages of 1 mg or 2 mg per day or matching placebo. A 1-week escalation period was followed by a 25-week maintenance period. MAIN OUTCOME MEASURE The primary prespecified measure of efficacy was the change in the total Unified Parkinson's Disease Rating Scal score between baseline and 26 weeks of treatment, comparing each active treatment group with the placebo group. RESULTS Monotherapy with rasagiline was effective in this 26-week study. The adjusted effect size for the total Unified Parkinson's Disease Rating Scale was -4.20 units comparing 1 mg of rasagiline and placebo (95% confidence interval, -5.66 to -2.73 units; P<.001) and -3.56 units comparing a 2-mg dosage and placebo (95% confidence interval, -5.04 to -2.08 units; P<.001). There were no meaningful differences in the frequency of adverse events or premature withdrawals among the treatment groups. CONCLUSIONS Rasagiline is effective as monotherapy for patients with early PD. The 2 dosages in this trial were both effective relative to placebo. Further study is warranted to evaluate the longer-term effects of rasagiline in PD.

The relationship between the learning organization concept and firms' financial performance: An empirical assessment

Abstract: The concept of the learning organization has received considerable attention in the scholarly literature because superior learning processes have been heralded as a source of competitive advantage. Organizations that embrace strategies consistent with the learning organization are thought to achieve improved performance. Yet few empirical studies have examined the relationship between the learning organization concept and firms' financial performance. To assess this association, the authors obtained managerial responses to the Watkins and Marsick Dimensions of the Learning Organization Questionnaire (DLOQ©) instrument along with both perceptual and objective measures of firms' financial performance. Results suggest a positive association between the learning organization concept and firms' financial performance. The article discusses implications for research and practice.

Task-Specific Ionic Liquids Incorporating Novel Cations for the Coordination and Extraction of Hg2+ and Cd2+: Synthesis, Characterization, and Extraction Studies

Abstract: A series of hydrophobic task-specific ionic liquids designed to extract Hg2+ and Cd2+ from water were prepared by appending urea-, thiourea-, and thioether-substituted alkyl groups to imidazoles and combining the resulting cationic species with PF6-. The new ionic liquids were characterized and investigated for their metal ion extraction capabilities. When used in liquid/liquid extraction of Hg2+ and Cd2+ from aqueous solutions, the metal ion distribution ratios increased several orders of magnitude, regardless of whether the ionic liquids were used as the sole extracting phase or doped into a series of [1-alkyl-3-methylimidazolium][PF6] (alkyl = n-C4-C8) ionic liquids to form a 1:1 solution. In the 1:1 mixtures, as the length of the alkyl chain increased from butyl to hexyl to octyl, the metal ion distribution ratios increased. Increasing the ratio TSIL/[C4mim][PF6] resulted in higher distribution ratios for both Hg2+ and Cd2+. Overall, the thiourea- and urea-derivatized cations yielded the highest distribution ratios, and those for Hg2+ were higher than those for Cd2+; however, a change in aqueous-phase pH does not promote the stripping of metal ions from the extracting phase. The combination of these imidazolium cations and PF6- produced ionic liquids with decreased thermal stability in comparison to [C(n)mim]-[PF6]. Gaussian98 restricted Hartree-Fock geometry optimizations for one of the thiourea-appended cations shows the charge delocalization around the ring and suggests that the thiourea group may aid in deprotonating the imidazolium ring and may be responsible for the lowered thermal stability of these cations.

Rowe and Kahn's Model of Successful Aging Revisited: Positive Spirituality--The Forgotten Factor.

Abstract: Purpose: We explain a new concept, positive spirituality, and offer evidence that links positive spirituality with health; describe effective partnerships between health professionals and religious communities; and summarize the information as a basis for strengthening the existing successful aging model proposed by Rowe and Kahn. Design and Methods: A missing component to Rowe and Kahn’s three-factor model of successful aging is identified, and we propose strengthening the model with a fourth factor, positive spirituality. Results: We developed an enhanced model of successful aging based on Rowe and Kahn’s theoretical framework. Evidence presented suggests that the addition of spirituality to interventions focused on health promotion has been received positively by older adults. Implications: Leaders in gerontology often fail to incorporate the growing body of scientific evidence regarding health, aging, and spirituality into their conceptual models to promote successful aging. The proposed enhancement of Rowe and Kahn’s model will help health professionals, religious organizations, and governmental agencies work collaboratively to promote wellness among older adults.

Hassles with taking out the garbage: aggravating aggresomes.

Abstract: Diverse human diseases ranging from amyloidosis to neurodegenerative diseases are now recognized as 'conformational diseases' caused by protein misfolding and protein aggregation. Misfolded and aggregated proteins are usually handled in the cell through chaperone-mediated refolding, or when that is impossible, destroyed by proteasomal degradation. Recent evidence suggests that cells might have evolved a third pathway that involves the sequestration of aggregated proteins into specialized 'holding stations' called aggresomes. The aggresomal pathway provides a mechanism by which aggregated proteins form particulate (approximately 200 nm) mini-aggregates that are transported on microtubules (MTs) towards the MT organizing center (MTOC) by a process mediated by the minus-end motor protein dynein. Once at the MTOC, the individual particles pack into a single, usually spherical aggresome (1-3 microm) that surrounds the MTOC. Aggresomes are dynamic: they recruit various chaperones and proteasomes, presumably to aid in the disposal of the aggregated proteins. In addition, the formation of an aggresome is likely to activate the autophagic clearance mechanism that terminates in lysosomal degradation. Hence, the aggresome pathway may provide a novel system to deliver aggregated proteins from the cytoplasm to lysosomes for degradation. Although it is clear that many pathological states correlate with the formation of aggresomes, their causal relationships remain hotly debated. Here, we describe the current state of our knowledge of the aggresome pathway and outline the open questions that provide the focus of current research.

Benefit of interferon β-1a on MSFC progression in secondary progressive MS

Abstract: Background: Interferon β-1a (IFNβ-1a, Avonex) is efficacious in relapsing forms of MS. Studies of other IFNβ preparations in secondary progressive MS (SPMS) yielded conflicting results. This study was undertaken to determine whether IFNβ-1a slowed disease progression in SP-MS. Methods: A total of 436 subjects with SPMS and Expanded Disability Status Scale (EDSS) score 3.5 to 6.5 were randomized to receive IFNβ-1a (60 μg) or placebo by weekly intramuscular injection for 2 years. The primary outcome measure, used for the first time in a large-scale MS trial, was baseline to month 24 change in the MS Functional Composite (MSFC), comprising quantitative tests of ambulation (Timed 25-Foot Walk), arm function (Nine-Hole Peg Test [9HPT]), and cognition (Paced Auditory Serial Addition Test [PASAT]). Results: Median MSFC Z-score change was reduced 40.4% in IFNβ-1a subjects (−0.096 vs −0.161 in placebo subjects, p = 0.033), an effect driven mainly by the 9HPT and PASAT. There was no discernible benefit on the EDSS, which in this range principally reflects walking ability. IFNβ-1a subjects had 33% fewer relapses ( p = 0.008). There was significant benefit on eight of 11 MS Quality of Life Inventory subscales. New or enlarging T2-hyperintense brain MRI lesions and gadolinium-enhancing lesions were reduced at months 12 and 24 (both p Conclusions: IFNβ-1a demonstrated benefit on MSFC progression, relapses, quality of life, and MRI activity in SPMS.

The Correlates of War (Cow) Project Direct Contiguity Data, Version 3.0:

Abstract: This research note summarizes version 3.0 of the Correlates of War Direct Contiguity data set, which covers the geographic proximity of all directly contiguous states in the international system du...

Magnitude of Functional CD8+ T-Cell Responses to the Gag Protein of Human Immunodeficiency Virus Type 1 Correlates Inversely with Viral Load in Plasma

Abstract: The importance of CD8 T-cell responses in the control of human immunodeficiency virus type 1 (HIV-1) infection has been demonstrated, yet few studies have been able to correlate these responses with markers of HIV-1 disease progression. This study measured cell-mediated immune responses using peripheral blood mononuclear cells (PBMC) obtained from 27 patients with chronic HIV-1 infection, the majority of whom were off antiretroviral therapy. The ELISPOT assay was used to detect gamma interferon-secreting PBMC after stimulation with overlapping HIV-1 peptides spanning the Gag, Pol, Env, and Nef proteins in addition to the baculovirus-derived p24 and gp160 proteins. All volunteers had responses to at least one HIV-1-specific peptide. All but one of the subjects (96%) responded to the Gag peptide pool, and 86% responded to the Pol and/or Nef peptide pools. The magnitude and the breadth of T-cell responses directed to either the Gag or p24 peptide pools correlated inversely with viral load in plasma (r 0.60, P < 0.001 and r 0.52, P < 0.005, respectively) and directly with absolute CD4 T-cell counts (r 0.54, P < 0.01 and r 0.39, P < 0.05, respectively) using the Spearman rank correlation test. Responses to the Pol and integrase peptide pools also correlated with absolute CD4 T-cell counts (r 0.45, P < 0.05 and r 0.49, P < 0.01, respectively). No correlation with markers of disease progression was seen with specific T-cell responses directed toward the Env or Nef peptides. These data serve as strong evidence that major histocompatibility complex class I presentation of Gag peptides is an essential feature for any HIV-1 vaccine designed to elicit optimal CD8 T-cell responses.

Psychological outcomes in long-term survivors of childhood leukemia, Hodgkin's disease, and non-Hodgkin's lymphoma: a report from the Childhood Cancer Survivor Study.

Abstract: Objective To evaluate and compare psychological outcomes in long-term survivors of pediatric leukemia, Hodgkin’s disease, and non-Hodgkin’s lymphoma and sibling controls Methods Adult survivors of childhood leukemia, Hodgkin’s disease, and non-Hodgkin’s lymphoma (N = 5736) and sibling controls (N = 2565) were administered a long-term follow-up questionnaire allowing assessment of symptoms associated with depression and somatic distress Results The majority of respondents in this study did not demonstrate symptomatology indicative of depression or somatic distress Survivors, however, were significantly more likely than sibling controls to report symptoms of depression and somatic distress Women were significantly more likely to indicate symptoms of depression and somatic distress than were men; however, this difference did not vary by survivor/sibling status Similarly, socioeconomic (SES) variables predicted symptomatic levels of depression and somatic distress for both survivors and siblings, and these effects did not vary by survivor/sibling status Among leukemia, Hodgkin’s disease, and non-Hodgkin’s lymphoma survivors, in addition to gender and SES, the only treatment variable that predicted scores indicating depressive symptomatology was exposure to intensive chemotherapy Exposure to intensive chemotherapy also predicted scores indicative of somatic distress symptoms No other medical variables, including diagnostic category, age at diagnosis, time since diagnosis, and duration of treatment, predicted symptomatic scores for depression and somatic distress Conclusions This large, sibling-controlled, multisite study of young adult survivors of childhood leukemia, Hodgkin’s disease, and non-Hodgkin’s lymphoma found that survivors had significant increased risk for reporting symptoms of depression and somatic distress and that intensive chemotherapy added to this risk However, being a cancer survivor did not compound the effects of gender and SES variables on the 2 outcomes measured The ability of SES, gender, and treatment-related variables to predict psychological symptoms in this cohort of childhood survivors and sibling controls calls for future research into varied biological and psychosocial pathways by which cancer influences future psychosocial functioning

Using forecasts of earnings to simultaneously estimate growth and the rate of return on equity investment

Abstract: We develop a method for simultaneously estimating the cost of equity capital and the growth in residual earnings that are implied by current stock prices, current book value of equity, and short-term forecasts of accounting earnings. We demonstrate the use of our method by calculating the expected equity risk premium. Our estimate is higher than estimates in extant studies that are based on the same earnings forecast data. The main difference between our study and these papers is that while they provide arguments supporting an assumed rate of growth beyond the forecast horizon, we estimate this rate.

Risk Factors for Progression of Common Carotid Atherosclerosis: The Atherosclerosis Risk in Communities Study, 1987–1998

Abstract: Intima-media thickness of the common carotid arteries is a marker of atherosclerosis and has been shown to be associated with prevalent and incident coronary heart disease and with coronary heart disease risk factors. The authors examined the association of baseline risk factors or change in risk factors with change in intima-media thickness over follow-up (1987-1998) in the Atherosclerosis Risk in Communities (ARIC) population-based cohort (baseline: age 45-64 years, n = 15,792). Subjects were members of households sampled in four areas of the United States. Either not adjusting for baseline intima-media thickness or doing so with correction for its measurement error resulted in statistically significant associations of change in intima-media thickness with baseline diabetes, current smoking, high density lipoprotein cholesterol, pulse pressure, white blood cell count, and fibrinogen. The associations were of a similar order of magnitude as anticipated from the authors' cross-sectional findings. Statistically significant associations were found between change in intima-media thickness and change in low density lipoprotein cholesterol and triglycerides and with onset of diabetes and hypertension. In summary, established risk factors for coronary heart disease are associated with the rate of change of subclinical atherosclerosis.

Vogt-Koyanagi-Harada disease.

Abstract: Vogt-Koyanagi-Harada disease is a chronic, granulomatous systemic autoimmune disease with manifestations in the ocular, central nervous, auditory, and integumentary systems. The target of attack seems to be antigens associated with melanocytes. Patients are usually of Asian, Middle Eastern, Asian Indian, Native American, or Hispanic ethnicity, and complain of neurologic symptoms quickly followed by decreased vision caused by a choroiditis, frequently with exudative retinal detachments. Corticosteroids are the mainstay of therapy, but other immunosuppressive therapy may be required. Complications, including cataract, glaucoma, choroidal neovascular membrane formation, and subretinal fibrosis, may limit final visual acuity.

Corporate Diversification: What Gets Discounted?

Abstract: Prior literature finds that diversified firms sell at a discount relative to the sum of the imputed values of their business segments. We explore this documented discount and argue that it stems from risk-reducing effects of corporate diversification. Consistent with this risk-reduction hypothesis, we find that ~a! shareholder losses in diversification are a function of firm leverage, ~b! all equity firms do not exhibit a diversification discount, and ~c! using book values of debt to compute excess value creates a downward bias for diversified firms. Overall, the results indicate that diversification is insignificantly related to excess firm value. A STREAM OF LITERATURE SUGGESTS that corporate diversification is associated with a substantial reduction in firm value. An underlying theme of this literature is that conglomerates tend to misallocate their investment funds by cross subsidizing poorly performing divisions. Berger and Ofek ~1995! ,f or example, document that conglomerates are prone to cross-subsidize investments in divisions with poor growth opportunities. Consistent with this finding, Rajan, Servaes, and Zingales ~2000! model the presence of power struggles among the firm’s divisions and show that diversification causes resources to f low to inefficient investments. Similarly, Scharfstein and Stein ~2000! demonstrate how rent-seeking divisional managers can subvert the internal capital allocation decision. These studies depict conglomerates as organizations that divert funds from stronger divisions to weaker ones and thereby misallocate their investment capital.1

DEMOCRATIZATION, POLITICAL INSTITUTIONS, AND ETHNIC CONFLICT A Pooled Time-Series Analysis, 1985-1998

Abstract: Although there has been much debate about whether democratization causes ethnic conflict, and many comparativists have argued about which kinds of political institutions are best for managing commu...

Use of Emergency Medical Services in Acute Myocardial Infarction and Subsequent Quality of Care Observations From the National Registry of Myocardial Infarction 2

Abstract: Background— National practice guidelines strongly recommend activation of the 9-1-1 Emergency Medical Systems (EMS) by patients with symptoms consistent with an acute myocardial infarction (MI). We examined use of the EMS in the United States and ascertained the factors that may influence its use by patients with acute MI. Methods and Results— From June 1994 to March 1998, the National Registry of Myocardial Infarction 2 enrolled 772 586 patients hospitalized with MI. We excluded those who transferred in, arrived at the hospital >6 hours from symptom onset, or who were in cardiogenic shock. We compared baseline characteristics and initial management for patients who arrived by ambulance versus self-transport. EMS was used in 53.4% of patients with MI, a proportion that did not vary significantly over the 4-year study period. Nonusers of the EMS were on average younger, male, and at relatively lower risk on presentation. In addition, payer status was significantly associated with EMS use. Use of EMS was in...