62 research outputs found

    Service Delivery in Rural Municipalities: Privatize, Cooperate, or Go It Alone?

    Get PDF
    Choices in production and contracting arrangements for a wide range of services were studied using data from approximately 1,000 small, mostly rural municipalities from Illinois, New Hampshire and Wisconsin. Results suggest the use of both for-profit contractors and cooperative agreements with other governments correlate negatively with population. Small municipalities are less likely to use competitive bidding processes, compare costs between production options, or report that privatization produces savings. Median income, rural geography, and ideology show statistically-significant associations with contracting choices. Respondents generally consider themselves ―satisfied‖ with services provided by contract, although satisfaction levels are lower than those associated with self-provision. Satisfaction associated with services provided by other governments is lower than satisfaction with services provided by private contractors, suggesting no tradeoff in service quality directly attributable to ―for-profit‖ contractors.privatization, municipal services, cooperation, Community/Rural/Urban Development, Public Economics,

    Gold nanoparticle interactions with endothelial cells cultured under physiological conditions

    Get PDF
    PEGylated gold nanoparticles (AuNPs) have an extended circulation time after intravenous injection in vivo and exhibit favorable properties for biosensing, diagnostic imaging, and cancer treatment. No impact of PEGylated AuNPs on the barrier forming properties of endothelial cells (ECs) has been reported, but recent studies demonstrated that unexpected effects on erythrocytes are observed. Almost all studies to date have been with static-cultured ECs. Herein, ECs maintained under physiological cyclic stretch and flow conditions and used to generate a blood–brain barrier model were exposed to 20 nm PEGylated AuNPs. An evaluation of toxic effects, cell stress, the release profile of pro-inflammatory cytokines, and blood–brain barrier properties showed that even under physiological conditions no obvious effects of PEGylated AuNPs on ECs were observed. These findings suggest that 20 nm-sized, PEGylated AuNPs may be a useful tool for biomedical applications, as they do not affect the normal function of healthy ECs after entering the blood stream

    Using molecular rotors to probe gelation

    Get PDF
    A series of fluorescent probes, including a number of molecular rotors, have been used to follow the self-assembly of dipeptide-based low molecular weight gelators. We show that these probes can be used to gain an insight into the assembly process. Thioflavin T, a commonly used stain for β-sheets, appears to act as a molecular rotor in these gelling systems, with the fluorescence data closely matching that of other rotors. The molecular rotor was incorporated into an assay system with glucose oxidase to enable glucose-concentration specific gelation and hence generating a fluorescent output. Applying this system to urine from patients with various levels of glycosuria (a symptom of diabetes), it was found to provide excellent correlation with different clinical assessments of diabetes. This demonstrates a new concept in gelation-linked biosensing for a real clinical problem

    Artificial cell membrane binding thrombin constructs drive in situ fibrin hydrogel formation

    Get PDF
    The incorporation of cells into tissue engineering scaffolds can be a major challenge. Here, the authors report on anchoring thrombin to cell membranes for the in situ formation of fibrin scaffolds around the modified cells, demonstrate scaffold formation in vitro and show cell survival in vivo

    Functionalized triblock copolymer vectors for the treatment of acute lymphoblastic leukemia

    Get PDF
    The chemotherapeutic Parthenolide is an exciting new candidate for the treatment of acute lymphoblastic leukemia, but like many other small-molecule drugs, it has low aqueous solubility. As a consequence, Parthenolide can only be administered clinically in the presence of harmful cosolvents. Accordingly, we describe the synthesis, characterization, and testing of a range of biocompatible triblock copolymer micelles as particle-based delivery vectors for the hydrophobic drug Parthenolide. The drug-loaded particles are produced via an emulsion-to-micelle transition method, and the effects of introducing anionic and cationic surface charges on stability, drug sequestration, biocompatibility, and efficacy are investigated. Significantly, we demonstrate high levels of efficacy in the organic solvent-free systems against human mesenchymal stem cells and primary T-acute lymphoblastic leukemia patient cells, highlighting the effectiveness of the delivery vectors for the treatment of acute lymphoblastic leukemia

    The structure of BVU2987 from Bacteroides vulgatus reveals a superfamily of bacterial periplasmic proteins with possible inhibitory function.

    Get PDF
    Proteins that contain the DUF2874 domain constitute a new Pfam family PF11396. Members of this family have predominantly been identified in microbes found in the human gut and oral cavity. The crystal structure of one member of this family, BVU2987 from Bacteroides vulgatus, has been determined, revealing a β-lactamase inhibitor protein-like structure with a tandem repeat of domains. Sequence analysis and structural comparisons reveal that BVU2987 and other DUF2874 proteins are related to β-lactamase inhibitor protein, PepSY and SmpA_OmlA proteins and hence are likely to function as inhibitory proteins

    The NANOGrav 11-year Data Set: High-precision Timing of 45 Millisecond Pulsars

    Get PDF
    We present high-precision timing data over time spans of up to 11 years for 45 millisecond pulsars observed as part of the North American Nanohertz Observatory for Gravitational Waves (NANOGrav) project, aimed at detecting and characterizing low-frequency gravitational waves. The pulsars were observed with the Arecibo Observatory and/or the Green Bank Telescope at frequencies ranging from 327 MHz to 2.3 GHz. Most pulsars were observed with approximately monthly cadence, and six high-timing-precision pulsars were observed weekly. All were observed at widely separated frequencies at each observing epoch in order to fit for time-variable dispersion delays. We describe our methods for data processing, time-of-arrival (TOA) calculation, and the implementation of a new, automated method for removing outlier TOAs. We fit a timing model for each pulsar that includes spin, astrometric, and (for binary pulsars) orbital parameters; time-variable dispersion delays; and parameters that quantify pulse-profile evolution with frequency. The timing solutions provide three new parallax measurements, two new Shapiro delay measurements, and two new measurements of significant orbital-period variations. We fit models that characterize sources of noise for each pulsar. We find that 11 pulsars show significant red noise, with generally smaller spectral indices than typically measured for non-recycled pulsars, possibly suggesting a different origin. A companion paper uses these data to constrain the strength of the gravitational-wave background

    The investigation and application of ice recrystallization inhibitors as cryoprotectants

    Get PDF
    There is a continuing need for improvements in the cryopreservation of clinically relevant cells, tissues and organs as advances in transplantation science and regenerative medicine rise alongside an aging populace that intensifies demand. Antifreeze (glyco)proteins (AF(G)Ps) and antifreeze proteins (AFPs) are classes of proteins found in cold acclimatized species. Ice recrystallization is a highly damaging process that occurs upon the thawing of frozen specimens with AF(G)Ps and AFPs limiting this effect in a process termed ice recrystallization inhibition (IRI). However AF(G)Ps and AFPs largely fail to improve in vitro and ex vivo cryopreservation due to their secondary property of dynamic ice shaping. The biocompatible and synthetically accessible polymer poly(vinyl alcohol) (PVA) has been shown to process a strong IRI activity. The IRI property of PVA along with numerous other polymers and polyols is investigated to highlight the uniqueness of PVA (Chapter 2). PVA is then explored as a cryoprotectant with red blood cells (Chapter 3), immortalized mammalian cell lines (Chapter 4) and primary cells (Chapter 5) with a significant advantageous effect observed with each cell type in terms of the number of cells recovered post thaw. However, this is despite the use of proportionately low concentrations of PVA compared to traditional membrane permeable cryoprotectants. The application of PVA as a cryoadjuvant could therefore improve the cryopreservation of cells, tissues and organs resulting in widespread clinical benefits

    In the deep freeze

    No full text
    • …
    corecore