bluuebunny/crossref_metadata_2025_split huggingface dataset:
Relationships between hydrology, spatial heterogeneity, and fish recruitment dynamics in a temperate floodplain river
Authors: Zeug S. C. , Winemiller K. O. 
Published: December 2007

AbstractFish populations in the Brazos River, Texas, were surveyed monthly for 2 years to determine the relative influence of hydrology and habitat characteristics on the recruitment dynamics of seven species representing three divergent life history strategies. Surveys were conducted in two oxbow lakes with different flood recurrence intervals and the main river channel. The first year was relatively dry with few oxbow‐river connections, whereas year 2 was relatively wet and connections between the main channel and floodplain habitats were common. Oxbow lakes supported greater juvenile abundances of most species relative to the main channel and were particularly important for nest building species with parental care. The river channel supported small species with extended reproductive periods and large, long‐lived species that are able to store reproductive potential during sub‐optimal periods. Hydrologic isolation was associated with greater rotifer densities in oxbows, and species with the greatest fecundity produced strong year classes during this period. Hydrologic connectivity did not increase juvenile production for most species, suggesting that recruitment dynamics in the Brazos River are similar to predictions of the low flow recruitment hypothesis (LFR). These results suggest that both hydrology and habitat heterogeneity interact with fish life history strategy to determine optimal conditions for recruitment and all three factors must be considered in restoration strategies for floodplain rivers. Copyright © 2007 John Wiley & Sons, Ltd.
Fast Projection‐Based Methods for the Least Squares Nonnegative Matrix Approximation Problem
Authors: Kim Dongmin , Sra Suvrit , Dhillon Inderjit S. 
Published: December 2007

AbstractNonnegative matrix approximation (NNMA) is a popular matrix decomposition technique that has proven to be useful across a diverse variety of fields with applications ranging from document analysis and image processing to bioinformatics and signal processing. Over the years, several algorithms for NNMA have been proposed, e.g. Lee and Seung's multiplicative updates, alternating least squares (ALS), and gradient descent‐based procedures. However, most of these procedures suffer from either slow convergence, numerical instability, or at worst, serious theoretical drawbacks. In this paper, we develop a new and improved algorithmic framework for the least‐squares NNMA problem, which is not only theoretically well‐founded, but also overcomes many deficiencies of other methods. Our framework readily admits powerful optimization techniques and as concrete realizations we present implementations based on the Newton, BFGS and conjugate gradient methods. Our algorithms provide numerical results superior to both Lee and Seung's method as well as to the alternating least squares heuristic, which was reported to work well in some situations but has no theoretical guarantees1. Our approach extends naturally to include regularization and box‐constraints without sacrificing convergence guarantees. We present experimental results on both synthetic and real‐world datasets that demonstrate the superiority of our methods, both in terms of better approximations as well as computational efficiency. Copyright © 2007 Wiley Periodicals, Inc., A Wiley Company Statistical Analy Data Mining 1: 000‐000, 2007
Cytotoxicity of Nanoparticles
Authors: Lewinski Nastassja , Colvin Vicki , Drezek Rebekah 
Published: December 2007

AbstractHuman exposure to nanoparticles is inevitable as nanoparticles become more widely used and, as a result, nanotoxicology research is now gaining attention. However, while the number of nanoparticle types and applications continues to increase, studies to characterize their effects after exposure and to address their potential toxicity are few in comparison. In the medical field in particular, nanoparticles are being utilized in diagnostic and therapeutic tools to better understand, detect, and treat human diseases. Exposure to nanoparticles for medical purposes involves intentional contact or administration; therefore, understanding the properties of nanoparticles and their effect on the body is crucial before clinical use can occur. This Review presents a summary of the in vitro cytotoxicity data currently available on three classes of nanoparticles. With each of these nanoparticles, different data has been published about their cytotoxicity due to varying experimental conditions as well as differing nanoparticle physiochemical properties. For nanoparticles to move into the clinical arena, it is important that nanotoxicology research uncovers and understands how these multiple factors influence the toxicity of nanoparticles so that their undesirable properties can be avoided.
Kinesin‐driven transport in cell‐free environment
Authors: Böhm Konrad J. 
Published: December 2007

AbstractConventional kinesin is an ATPase‐active motor protein that is involved in the microtubule‐dependent transport of cytoplasmic cargoes. The present paper provides a condensed overview on kinesin‐1 and its motility generation outside a living cell. Moreover, it demonstrates that the neuron‐specific kinesin KIF5A enables the formation of microtubules under conditions where pure tubulin does not assemble.
Nonclassical secretion of human catalase on the surface of CHO cells is more efficient than classical secretion
Authors: He Zuyong , Sun Xiuzhu , Mei Gui , Yu Shengli , Li Ning 
Published: December 2007

AbstractThere is a great demand for improved production of therapeutic proteins using mammalian cell expression systems and transgenic animals. There have been intensive endeavors to optimize production at the transcriptional and translational levels, but comparatively little attention has been paid to the secretory level, especially to nonclassical secretion. To compare the efficiencies of classical and nonclassical secretion, we expressed GFP‐tagged human catalase conjugated with a classical signal peptide and with several short peptides derived from mouse Engrailed 2 (mEN2) homeoprotein for nonclassical secretion and internalization in CHO cells. Surprisingly, the results showed that the secretory efficiency was significantly greater (up to 2.3 fold) than classical secretion when the fusion protein was driven by the secretory sequence (SS) of mEN2, and up to 1.9 fold when the classical secretion process was modified by incorporating the internalization sequence (IS) of mEN2. The effect of these short peptides on nonclassical secretion and internalization may indicate potential applications in the improved production of complex therapeutic proteins in mammalian cell expression systems and transgenic animals.
Age‐associated alterations of lipofuscin, membrane‐bound ATPases and intracellular calcium in cortex, striatum and hippocampus of rat brain: protective role of glutathione monoester
Authors: Murali Ganesan , Panneerselvam Kavin S. , Panneerselvam Chinnakkannu 
Published: December 2007

AbstractBrain aging has become an area of intense research and a subject of much speculation fueled largely from the widely recognized fact that age is the biggest risk factor in most neurodegenerative diseases and age‐related increase of reactive oxygen species is particularly detrimental to postmitotic tissues. In the present study, we have evaluated the possible role of glutathione monoester (GME), when administered intraperitoneally (12 mg/kg body weight) for 20 days on age‐associated changes in the levels of lipofuscin, Na+K+, Mg2+, Ca2+ ATPase activities and intracellular calcium levels in discrete brain regions of young and aged male albino Wistar rats. An age‐associated increase in lipofuscin, intracellular calcium in cortex, striatum and hippocampus was observed and contradictorily, a decrease in the activities of membrane‐bound enzyme activities was also observed. Supplementation of GME brought these changes to near normalcy. Thus, GME improves neuronal antioxidant status, thereby effectively attenuating any putative increase in oxidative stress with age.
Analysis of DNA structure as a 2D random walk by complex wavelet transform
Authors: Postnikov Eugene , Loskutov Alexander , Larionov Sergey , Ryadchenko Evgeny , Kiseliov Roman 
Published: December 2007

AbstractWe propose the original method of the time-scale wavelet analysis of DNA sequence represented as a 2D walk on a complex plane. Namely, we consider the mapping of two irreducible A − T and G − C sequences into a walk trajectory in the plane AGTC (firstly proposed by M. Gates) as a unique complex-valued function. This function is processed with the new algorithm of the continuous wavelet transform with the Morlet wavelet. This method is based on the representation of the transform’s result as a solution of the specific Cauchy problem for the system of PDE. As an example, we applied the described algorithm to a part of the telomer region of the 22 human chromosome and demonstated the high exactness. Moreover, it is very fast and it provides wide opportunities for the analysis of large genome data samples.
Risk of Hand or Glove Contamination After Contact With Patients Colonized With Vancomycin-ResistantEnterococcusor the Colonized Patients' Environment
Authors: Hayden Mary K. , Blom Donald W. , Lyle Elizabeth A. , Moore Charity G. , Weinstein Robert A. 
Published: December 2007

Objective.To estimate the level of hand or glove contamination with vancomycin-resistant enterococci (VRE) among healthcare workers (HCWs) who touch a patient colonized with VRE and/or the colonized patient's environment during routine care.Design.Structured observational study.Setting.Medical intensive care unit of a 700-bed, tertiary-care teaching hospital.Participants.VRE-colonized patients and their caregivers.Methods.We obtained samples from sites on the intact skin of 22 patients colonized with VRE and samples from sites in the patients' rooms, before and after routine care, during 27 monitoring episodes. A total of 98 unique HCWs were observed during 131 HCW observations. Observers recorded the sites touched by HCWs. Culture samples were obtained from HCWs' hands and gloves before and after care.Results.VRE were isolated from a mean (±SD) of 55% ± 24% of patient sites (n= 256) and 17% ± 12% of environmental sites (n= 1,572). Most HCWs (131 [56%]) touched both the patient and the patient's environment; no HCW touched only the patient. Of 103 HCWs whose hand samples were negative for VRE when they entered the room, 52% contaminated their hands or gloves after touching the environment, and 70% contaminated their hands or gloves after touching the patient and the environment (P= .101). In a univariate logistic regression model, the risk of hand or glove contamination was associated with the number of contacts made (odds ratio, 1.1 [95% confidence interval, 1.01-1.19). In a multivariate model, the effect of the number of contacts could not be distinguished from the effect of type of contact (ie, touching the environment alone or touching both the patient and the environment). Overall, 37% of HCWs who did not wear gloves contaminated their hands, and 5% of HCWs who wore gloves did so (an 86% difference).Conclusion.HCWs were nearly as likely to have contaminated their hands or gloves after touching the environment in a room occupied by a patient colonized by VRE as after touching the colonized patient and the patient's environment. Gloves were highly protective with respect to hand contamination.
Influenza Vaccination Among Registered Nurses: Information Receipt, Knowledge, and Decision-Making at an Institution With a Multifaceted Educational Program
Authors: Ofstead Cori L. , Tucker Sharon J. , Beebe Timothy J. , Poland Gregory A. 
Published: December 2007

Objective.To evaluate the receipt of information and knowledge about influenza and vaccination, as well as influenza vaccination status and reasons for declining vaccination, among registered nurses.Design.Cross-sectional survey of registered nurses (RNs).Setting.A large tertiary medical center with a long-standing, multifaceted influenza vaccination program and relatively high vaccination rates among employees overall (76.5%).Participants.Randomly selected group of 990 RNs employed as inpatient staff nurses at the institution.Results.The survey was completed by 513 (51.8%) of 990 RNs. Most RNs (86.7%) had received an influenza vaccination in the past, and 331 (64.5%) intended to receive vaccination during the 2005-2006 influenza season. More than 90% of RNs acknowledged exposure to educational bulletins, and most had received information about influenza severity (383 [74.7%]), transmission (398 [77.6%]), vaccine safety (416 [81.1%]), and the time and location of free vaccination (460 [89.7%]). A majority (436 [85.0%]) felt they had received all the information they needed to make good decisions about vaccination. However, only 49 RNs (9.6%) gave correct answers to more than 85% of the knowledge questions on the survey. The reasons most frequently reported for declining vaccination were doubts about the risk of influenza and the need for vaccination, concerns about vaccine effectiveness and side effects, and dislike of injections.Conclusions.RNs exposed to a longstanding, multifaceted educational program had received information about influenza vaccination, but misconceptions were common and only 331 (64.5%) intended to receive vaccination. Strategies other than educational interventions are needed to increase influenza vaccination rates and thereby to ensure healthcare worker and patient safety.
Use of a Pandemic Preparedness Drill to Increase Rates of Influenza Vaccination Among Healthcare Workers
Authors: Kuntz Jennifer L. , Holley Stephanie , Helms Charles M. , Cavanaugh Joseph E. , Berg Jeff Vande , Herwaldt Loreen A. , Polgreen Philip M. 
Published: December 2007

Objective.To determine the effect of a pandemic influenza preparedness drill on the rate of influenza vaccination among healthcare workers (HCWs).Design.Before-after intervention trial.Setting.The University of Iowa Hospitals and Clinics (UIHC), a large, academic medical center, during 2005.Subjects.Staff members at UIHC.Methods.UIHC conducted a pandemic influenza preparedness drill that included a goal of vaccinating a large number of HCWs in 6 days without disrupting patient care. Peer vaccination and mobile vaccination teams were used to vaccinate HCWs, educational tools were distributed to encourage HCWs to be vaccinated, and resources were allocated on the basis of daily vaccination reports. Logit models were used to compare vaccination rates achieved during the 2005 vaccination drill with the vaccination rates achieved during the 2003 vaccination campaign.Results.UIHC vaccinated 54% of HCWs (2,934 of 5,467) who provided direct patient care in 6 days. In 2 additional weeks, this rate increased to 66% (3,625 of 5,467). Overall, 66% of resident physicians (311 of 470) and 63% of nursing staff (1,429 of 2,255) were vaccinated. Vaccination rates in 2005 were significantly higher than the hospitalwide rate of 41% (5,741 of 14, 086) in 2003.Conclusions.UIHC dramatically increased the influenza vaccination rate among HCWs by conducting a pandemic influenza preparedness drill. Additionally, the drill allowed us to conduct a bioemergency drill in a realistic scenario, use innovative methods for vaccine delivery, and secure administrative support for future influenza vaccination campaigns. Our study demonstrates how a drill can be used to improve vaccination rates significantly.
Importance of Bacterial Burden Among Methicillin-Resistant Staphylococcus aureus Carriers in a Long-Term Care Facility
Authors: Stone Nimalie D. , Lewis Donna R. , Lowery H. K. , Darrow Lyndsey A. , Kroll Catherine M. , Gaynes Robert P. , Jernigan John A. , McGowan John E. , Tenover Fred C. , Richards Chesley L. 
Published: December 2007

Objective.To evaluate the prevalence and transmission of methicillin-resistant Staphylococcus aureus (MRSA) nasal colonization, as well as risk factors associated with MRSA carriage, among residents of a long-term care facility (LTCF).Design.Prospective, longitudinal cohort study.Setting.A 100-bed Veterans Administration LTCFParticipants.All current and newly admitted residents of the LTCF during an 8-week study period.Methods.Nasal swab samples were obtained weekly and cultured on MRSA-selective media, and the cultures were graded for growth on a semiquantitative scale from 0 (no growth) to 6 (heavy growth). Epidemiologic data for the periods before and during the study were collected to assess risk factors for MRSA carriage.Results.Of 83 LTCF residents, 49 (59%) had 1 or more nasal swab cultures that were positive for MRSA; 34 (41%) were consistently culture-negative (designated “noncarriers”). Of the 49 culture-positive residents, 30 (36% of the total of 83 residents) had all cultures positive for MRSA (designated “persistent carriers”), and 19 (23% of the 83 residents) had at least 1 culture, but not all cultures, positive for MRSA (designated “intermittent carriers”). Multivariate analysis showed that participants with at least 1 nasal swab culture positive for MRSA were likely to have had previous hospitalization (odds ratio, 3.9) or wounds (odds ratio, 8.2). Persistent carriers and intermittent carriers did not differ in epidemiologic characteristics but did differ in mean MRSA growth score (3.7 vs 0.7; P < .001).Conclusions.Epidemiologic characteristics differed between noncarriers and subjects with at least 1 nasal swab culture positive for MRSA. However, in this LTCF population, only the degree of bacterial colonization (as reflected by mean MRSA growth score) distinguished persistent carriers from intermittent carriers. Understanding the burden of colonization may be important when determining future surveillance and control strategies.
Clinical and Economic Consequences of Failure of Initial Antibiotic Therapy for Hospitalized Patients With Complicated Skin and Skin-Structure Infections
Authors: Edelsberg John , Berger Ariel , Weber David J. , Mallick Rajiv , Kuznik Andreas , Oster Gerry 
Published: December 2007

Objective.To estimate the consequences of failure of initial antibiotic therapy for patients with complicated skin and skin-structure infections.Design.Retrospective cohort study.Setting.Large US multihospital database.Patients.We identified a total of 47,219 patients (age 18 years or older) who were admitted to the hospital for complicated skin and skin-structure infections from April 1, 2003, through March 31, 2004, and who received intravenous antibiotics during the first 2 hospital-days (ie, initial antibiotic therapy). Failure of therapy was defined as drainage, debridement, or receipt of other intravenous antibiotics at any subsequent time (except for changes to narrower-spectrum agents or any therapy change immediately before discharge). Predictors of failure of antibiotic therapy and mortality were examined using multivariate logistic regression. Analysis of covariance was used to estimate the impact of treatment failure on duration of intravenous antibiotic therapy, length of stay, and total inpatient charges.Results.For 10,782 admitted patients (22.8%), there was evidence of failure of initial antibiotic therapy. In multivariate analyses, treatment failure was associated with receipt of vasoactive medications during the first 2 hospital-days (odds ratio [OR], 1.66 [95% confidence interval {CI}, 1.19-2.31]), initiation of antibiotic therapy in the intensive care unit (OR, 1.53 [95% CI, 1.28-1.84]), and the patient's Charlson comorbidity index (OR per 1-point increase, 1.06 [95% CI, 1.04-1.08]); treatment failure was also was associated with a 3-fold increase in mortality (OR, 2.91 [95% CI, 2.34-3.62]). Compared with patients for whom initial treatment was successful, patients who experienced treatment failure received intravenous antibiotic therapy for a mean of 5.7 additional days, were hospitalized for a mean of 5.4 additional days, and incurred a mean of $5,285 (in 2003 dollars) in additional inpatient charges (all P <.01).Conclusion.Failure of initial antibiotic therapy in the treatment of complicated skin and skin-structure infections is associated with significantly worse clinical and economic outcomes.
Patient Attitudes Regarding Participation in Studies of Antimicrobial Resistance
Authors: Tolomeo Pam , Wheeler Mary , Metlay Joshua P. , Armstrong Katrina , Fishman Neil O. , Bilker Warren B. , Lautenbach Ebbing 
Published: December 2007

Background.A number of recent studies of antimicrobial resistance have focused on the role of antimicrobial-resistant pathogens that colonize the gastrointestinal tract. However, participation rates have been low in studies that involve fecal sampling. Attitudes toward such studies among potential study participants have not been assessed.Methods.We conducted a cross-sectional survey, enrolling 3 groups of inpatients from a large academic center. Group 1 consisted of patients who had previously participated in a cohort study of fluoroquinolone-resistant Escherichia coli, which involved the collection of perirectal swab samples. Group 2 consisted of patients who had previously refused to participate in the study of fluoroquinolone-resistant E. coli. Group 3 consisted of patients who had never been asked to participate in the study of the fluoroquinolone-resistant E. coli. The survey assessed patients' attitudes and beliefs regarding medical research and their willingness to consent to collection of a perirectal swab sample. Response options were recorded on a 5-point Likert scale. The Fisher exact test was used to compare dichotomized responses across study groups.Results.A total of 90 patients were surveyed: there were 29 in group 1 and in group 2 and 32 in group 3. Of 90 patients, 31 (35%) believed researchers might run additional tests on collected samples without informing the patient, whereas 25 (27%) believed persons other than the research team might gain access to study results. The belief that a person could get sicker as a result of a having a perirectal swab sample collected was significantly more common among patients who had previously refused to participate in the fluoroquinolone-resistant E. coli study.Conclusion.This study highlights important beliefs and attitudes that are associated with the likelihood of participating in studies of antimicrobial resistance. Explicitly addressing these concerns with eligible patients is critical to optimize participation in future studies.