200 research outputs found
Electroconductive PET/SWNT Films by Solution Casting
The market for electrically conductive polymers is rapidly growing, and an emerging pathway for attaining these materials is via polymer-carbon nanotube (CNT) nanocomposites, because of the superior properties of CNTs. Due to their excellent electrical properties and anisotropic magnetic susceptibility, we expect CNTs could be easily aligned to maximize their effectiveness in imparting electrical conductivity to the polymer matrix. Single-walled carbon nanotubes (SWNT) were dispersed in a polyethylene terephthalate (PET) matrix by solution blending then cast onto a glass substrate to create thin, flexible films. Various SWNT loading concentrations were implemented (0.5, 1.0, and 3.0 wt.%) to study the effect of additive density. The processing method was repeated to produce films in the presence of magnetic fields (3 and 9.4 Tesla). The SWNTs showed a high susceptibility to the magnetic field and were effectively aligned in the PET matrix. The alignment was characterized with Raman spectroscopy. Impedance spectroscopy was utilized to study the electrical behavior of the films. Concentration and dispersion seemed to play very important roles in improving electrical conductivity, while alignment played a secondary and less significant role. The most interesting result proved to be the effect of a magnetic field during processing. It appears that a magnetic field may improve dispersion of unmodified SWNTs, which seems to be more important than alignment. It was concluded that SWNTs offer a good option as conductive, nucleating filler for electroconductive polymer applications, and the utilization of a magnetic field may prove to be a novel method for CNT dispersion that could lead to improved nanocomposite materials
Sociocultural Learning And The Hope For School Change: Participatory Action Research At A Public Elementary School
Educational reform in the United States has failed to adequately account for the complexities of urban schooling. Instead of spurring systematic school change, these oftentimes bureaucratic and authoritarian reform efforts have inspired widespread institutional distrust, which undermines improvement efforts and demoralizes school professionals. Persistent failure of “top-down” reform has fueled the use of democratic or “bottom-up” approaches to more sufficiently grapple with the highly dynamic nature of urban public schools. Participatory Action Research (PAR) has become an increasingly popular inquiry method to facilitate robust and democratic institutional change, whereby university-based researchers and school practitioners co-construct knowledge through a collaborative inquiry process. This 10-month case study (2010-2011) employed sociocultural learning theory and the tenets of PAR to examine its implementation at a public elementary school in a major northeastern city. In order to ameliorate a distressing school issue, participant interviews (N=10), school observations (+100 hours), and typewritten reflections (i.e., weekly memos; 100-200 words) captured detailed narratives associated with the evolution, challenges, as well as effective practice of PAR within a university and school partnership. Four interrelated themes of PAR implementation emerged: (1) hopes for the project; (2) vision of team roles; (3) learning through boundary crossing; and (4) boundary object potential
CD8α is expressed by human monocytes and enhances FcγR-dependent responses
Abstract Background CD8α enhances the responses of antigen-specific CTL activated through TCR through binding MHC class I, favoring lipid raft partitioning of TCR, and inducing intracellular signaling. CD8α is also found on dendritic cells and rat macrophages, but whether CD8α enhances responses of a partner receptor, like TCR, to activate these cells is not known. TCR and FcR, use analogous or occasionally interchangeable signaling mechanisms suggesting the possibility that CD8α co-activates FcR responses. Interestingly, CD8α+ monocytes are often associated with rat models of disease involving immune-complex deposition and FcR-mediated pathology, such as arthritis, glomerulonephritis, ischaemia, and tumors. While rat macrophages have been shown to express CD8α evidence for CD8α expression by mouse or human monocytes or macrophages was incomplete. Results We detected CD8α, but not CD8β on human monocytes and the monocytic cell line THP-1 by flow cytometry. Reactivity of anti-CD8α mAb with monocytes is at least partly independent of FcR as anti-CD8α mAb detect CD8α by western blot and inhibit binding of MHC class I tetramers. CD8α mRNA is also found in monocytes and THP-1 suggesting CD8α is synthesized by monocytes and not acquired from other CD8α+ cell types. Interestingly, CD8α from monocytes and blood T cells presented distinguishable patterns by 2-D electrophoresis. Anti-CD8α mAb alone did not activate monocyte TNF release. In comparison, TNF release by human monocytes stimulated in a FcR-dependent manner with immune-complexes was enhanced by inclusion of anti-CD8α mAb in immune-complexes. Conclusion Human monocytes express CD8α. Co-engagement of CD8α and FcR enhances monocyte TNF release, suggesting FcR may be a novel partner receptor for CD8α on innate immune cells.</p
Tuning Phage for Cartilage Regeneration
The ever-broadening scope of phage research has left behind the simplistic view of studying phages as just model systems in phage biology to a much broader application ranging from ecological management to immunity. Improved throughput technology in crystallography and structural studies has helped our understanding of these systems as supramolecular machines that possess the capacity of self-assembly. The idea of phages as self-assembling supramolecular nano-machines that are bioactive biomaterials in characteristics, tunable and easily producible have lent its utility to recent fields such as regenerative medicine and tissue engineering. Due to low metabolic activity and slow nutrient diffusion within cartilage, damage to this tissue often inevitably consist of slow and delayed regeneration and healing, the restriction of blood from reaching most part of this tissue and the resultant limitations in the availability of oxygen and other essential amino acids dictates a very slow systemic metabolic response also since transports system in this tissue have to employ less speedy forms. Cartilage regeneration therefore is a huge challenge. This chapter takes a look at the application of the phage display technology in cartilage tissue regeneration
Prevalence of Pilomatricoma in Turner Syndrome: Findings From a Multicenter Study
IMPORTANCE: The absence of data on the prevalence of pilomatricoma among patients with Turner syndrome served as the catalyst for this multicenter investigation.
OBJECTIVES: To ascertain the prevalence of pilomatricoma among patients with Turner syndrome and to determine any association between the development of pilomatricomas and the use of exogenous hormones in patients with Turner syndrome.
DESIGN: A retrospective medical record review from January 1, 2000, through January 1, 2010, was performed of all patients with Turner syndrome. Data on pilomatricomas and the use of hormone therapy were collected.
SETTING: University of California-Davis Medical Center, University of Nebraska Medical Center, and The University of North Carolina at Chapel Hill.
PARTICIPANTS: Patients with a diagnosis of Turner syndrome.
MAIN OUTCOME MEASURES: Prevalence of concomitant pilomatricoma and diagnosis of Turner syndrome. Secondary outcome measures included the use of the exogenous hormones estrogen or recombinant human growth hormone (rhGH).
RESULTS: In total, 311 patients with Turner syndrome were identified from these 3 institutions. Among them, 8 patients (2.6%) were diagnosed as having pilomatricomas. Before the development of pilomatricomas, 5 patients had been treated with rhGH but not estrogen, 1 patient had received estrogen but not rhGH, and 2 patients did not receive either therapy.
CONCLUSIONS AND RELEVANCE: Although the prevalence of pilomatricoma among the general population is unknown, this study demonstrates a high prevalence (2.6%) of pilomatricomas among patients with Turner syndrome. No apparent relationship was noted among our patients or in the literature between the use of rhGH and the development of pilomatricomas
The Incidence of Venous Thromboembolism in Children Following Colorectal Resection for Inflammatory Bowel Disease: A Multi-Center Study
Background/Purpose
Children with inflammatory bowel disease (IBD) have increased risk for venous thromboembolism (VTE). We sought to determine incidence and risk factors for postoperative VTE in a multicenter cohort of pediatric patients undergoing colorectal resection for IBD.
Methods
Retrospective review of children ≤18 years who underwent colorectal resection for IBD from 2010 to 2016 was performed at four children's hospitals. Primary outcome was VTE that occurred between surgery and last follow-up. Factors associated with VTE were determined using univariable and multivariable analyses.
Results
Two hundred seventy-six patients were included with median age 15 years [13,17]. Forty-two children (15%) received perioperative VTE chemoprophylaxis, and 88 (32%) received mechanical prophylaxis.
DVT occurred in 12 patients (4.3%) at a median of 14 days postoperatively [8,147]. Most were portomesenteric (n = 9, 75%) with the remaining catheter-associated DVTs in extremities (n = 3, 25%).
There was no association with chemoprophylaxis (p > 0.99). On Cox regression, emergent procedure [HR 18.8, 95%CI: 3.18–111], perioperative plasma transfusion [HR 25.1, 95%CI: 2.4–259], and postoperative infectious complication [HR 10.5, 95%CI: 2.63–41.8] remained predictive of DVT.
Conclusion
Less than 5% of pediatric IBD patients developed postoperative VTE. Chemoprophylaxis was not protective but rarely used. Patients with risk factors identified in this study should be monitored or given prophylaxis for VTE
HMDB: the Human Metabolome Database
The Human Metabolome Database (HMDB) is currently the most complete and comprehensive curated collection of human metabolite and human metabolism data in the world. It contains records for more than 2180 endogenous metabolites with information gathered from thousands of books, journal articles and electronic databases. In addition to its comprehensive literature-derived data, the HMDB also contains an extensive collection of experimental metabolite concentration data compiled from hundreds of mass spectra (MS) and Nuclear Magnetic resonance (NMR) metabolomic analyses performed on urine, blood and cerebrospinal fluid samples. This is further supplemented with thousands of NMR and MS spectra collected on purified, reference metabolites. Each metabolite entry in the HMDB contains an average of 90 separate data fields including a comprehensive compound description, names and synonyms, structural information, physico-chemical data, reference NMR and MS spectra, biofluid concentrations, disease associations, pathway information, enzyme data, gene sequence data, SNP and mutation data as well as extensive links to images, references and other public databases. Extensive searching, relational querying and data browsing tools are also provided. The HMDB is designed to address the broad needs of biochemists, clinical chemists, physicians, medical geneticists, nutritionists and members of the metabolomics community. The HMDB is available at
Brainstem Respiratory Oscillators Develop Independently of Neuronal Migration Defects in the Wnt/PCP Mouse Mutant looptail
The proper development and maturation of neuronal circuits require precise migration of component neurons from their birthplace (germinal zone) to their final positions. Little is known about the effects of aberrant neuronal position on the functioning of organized neuronal groups, especially in mammals. Here, we investigated the formation and properties of brainstem respiratory neurons in looptail (Lp) mutant mice in which facial motor neurons closely apposed to some respiratory neurons fail to migrate due to loss of function of the Wnt/Planar Cell Polarity (PCP) protein Vangl2. Using calcium imaging and immunostaining on embryonic hindbrain preparations, we found that respiratory neurons constituting the embryonic parafacial oscillator (e-pF) settled at the ventral surface of the medulla in Vangl2Lp/+ and Vangl2Lp/Lp embryos despite the failure of tangential migration of its normally adjacent facial motor nucleus. Anatomically, the e-pF neurons were displaced medially in Lp/+ embryos and rostro-medially Lp/Lp embryos. Pharmacological treatments showed that the e-pF oscillator exhibited characteristic network properties in both Lp/+ and Lp/Lp embryos. Furthermore, using hindbrain slices, we found that the other respiratory oscillator, the preBötzinger complex, was also anatomically and functionally established in Lp mutants. Importantly, the displaced e-pF oscillator established functional connections with the preBötC oscillator in Lp/+ mutants. Our data highlight the robustness of the developmental processes that assemble the neuronal networks mediating an essential physiological function
Estimated herd prevalence and sequence types of Coxiella burnetii in bulk tank milk samples from commercial dairies in Indiana
Development of Functional and Molecular Correlates of Vaccine-Induced Protection for a Model Intracellular Pathogen, F. tularensis LVS
In contrast with common human infections for which vaccine efficacy can be evaluated directly in field studies, alternative strategies are needed to evaluate efficacy for slowly developing or sporadic diseases like tularemia. For diseases such as these caused by intracellular bacteria, serological measures of antibodies are generally not predictive. Here, we used vaccines varying in efficacy to explore development of clinically useful correlates of protection for intracellular bacteria, using Francisella tularensis as an experimental model. F. tularensis is an intracellular bacterium classified as Category A bioterrorism agent which causes tularemia. The primary vaccine candidate in the U.S., called Live Vaccine Strain (LVS), has been the subject of ongoing clinical studies; however, safety and efficacy are not well established, and LVS is not licensed by the U.S. FDA. Using a mouse model, we compared the in vivo efficacy of a panel of qualitatively different Francisella vaccine candidates, the in vitro functional activity of immune lymphocytes derived from vaccinated mice, and relative gene expression in immune lymphocytes. Integrated analyses showed that the hierarchy of protection in vivo engendered by qualitatively different vaccines was reflected by the degree of lymphocytes' in vitro activity in controlling the intramacrophage growth of Francisella. Thus, this assay may be a functional correlate. Further, the strength of protection was significantly related to the degree of up-regulation of expression of a panel of genes in cells recovered from the assay. These included IFN-γ, IL-6, IL-12Rβ2, T-bet, SOCS-1, and IL-18bp. Taken together, the results indicate that an in vitro assay that detects control of bacterial growth, and/or a selected panel of mediators, may ultimately be developed to predict the outcome of vaccine efficacy and to complement clinical trials. The overall approach may be applicable to intracellular pathogens in general
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