183 research outputs found

    The role of plasma wave turbulence in the formation of shock waves in collisionless plasmas

    Get PDF
    A data set containing measurements for approximately 100 shock crossings was compiled, and plasma wave profiles were plotted in conjunction with magnetic field data. Three emissions analyzed include upstream electron plasma oscillations, ion acoustic noise, and low frequency electromagnetic noise. The data demonstrate that the observed waves are consistent with generation by the kinetic cross-field streaming instability. Reanalysis of shock overshoots prompted by the presence of plasma feet upstream of nominally subcritical shocks leads to the conclusion that no firm evidence exists for a sharp subcritical supercritical transition. Electron plasma oscillations persist up to the ramps of subcritical shocks and begin decaying at the front edge of the feet of supercritical shocks. Their intensity is anticorrelated with the amplitude of the foot ion acoustic noise. Wave measurements support the predicted predominance of lower hybrid-like modes over ion acoustic noise in the production of resistive (plasma) heating. Evidence for variable shock normal angles is seen upstream from nominally quasiparallel shocks. The first cases of very strong electron heating observed at the terrestrial bow shock were discovered

    Physical non-viral gene delivery methods for tissue engineering

    Get PDF
    The integration of gene therapy into tissue engineering to control differentiation and direct tissue formation is not a new concept; however, successful delivery of nucleic acids into primary cells, progenitor cells, and stem cells has proven exceptionally challenging. Viral vectors are generally highly effective at delivering nucleic acids to a variety of cell populations, both dividing and non-dividing, yet these viral vectors are marred by significant safety concerns. Non-viral vectors are preferred for gene therapy, despite lower transfection efficiencies, and possess many customizable attributes that are desirable for tissue engineering applications. However, there is no single non-viral gene delivery strategy that “fits-all” cell types and tissues. Thus, there is a compelling opportunity to examine different non-viral vectors, especially physical vectors, and compare their relative degrees of success. This review examines the advantages and disadvantages of physical non-viral methods (i.e., microinjection, ballistic gene delivery, electroporation, sonoporation, laser irradiation, magnetofection, and electric field-induced molecular vibration), with particular attention given to electroporation because of its versatility, with further special emphasis on Nucleofection™. In addition, attributes of cellular character that can be used to improve differentiation strategies are examined for tissue engineering applications. Ultimately, electroporation exhibits a high transfection efficiency in many cell types, which is highly desirable for tissue engineering applications, but electroporation and other physical non-viral gene delivery methods are still limited by poor cell viability. Overcoming the challenge of poor cell viability in highly efficient physical non-viral techniques is the key to using gene delivery to enhance tissue engineering applications

    Reduced hypoglycemia risk in type 2 diabetes patients switched to/initiating insulin glargine 300 vs 100 U/ml: A european real-world study

    Get PDF
    Introduction: Randomized controlled trials and real-world data from the USA have shown similar glycemic control with insulin glargine 300 U/ml (Gla-300) and insulin glargine 100 U/ml (Gla-100) and reduced hypoglycemia risk with Gla-300. This real-world study describes the efficacy and safety of Gla-300 and Gla-100 in patients with type 2 diabetes (T2D) in France, Spain, and Germany. Methods: This retrospective chart review analysis used anonymized data for adults with T2D switching basal insulin analog (BIA) therapy to Gla-300 or Gla-100, or insulin-naïve patients initiating Gla-300 or Gla-100. Outcomes included change from baseline to 6-month follow-up in glycated hemoglobin A1c (A1C), total and severe hypoglycemia incidences and events, insulin dose, and reasons for BIA choice. Results: Six hundred sixty-five physicians (33.8% Spain, 31.7% France, 34.4% Germany) provided chart data for patients switching to Gla-300 (n = 679) or Gla-100 (n = 429) or initiating Gla-300 (n = 719) or Gla-100 (n = 711). After adjustment for baseline characteristics, A1C reductions from baseline were similar for patients switching to Gla-300 or Gla-100 (- 0.87% vs. - 0.93%; p = 0.326) while those switched to Gla-300 vs. Gla-100 had a significantly greater mean reduction in hypoglycemic events (- 1.29 vs. - 0.81 events during 6 months; p = 0.012). Mean insulin doses after titration were 0.43 ± 0.36 and 0.40 ± 0.28 U/kg in Gla-300 and Gla-100 switchers, respectively. Factors that significantly influenced BIA choice included a lower risk of hypoglycemia (for Gla-300) and physician familiarity (for Gla-100). Outcomes for insulin-naïve patients were broadly similar to those of switchers. Conclusions: In this real-world European study, patients with T2D who switched therapy to Gla-300 or Gla-100 had improved glycemic control and reduced hypoglycemia at 6 months, with significant hypoglycemia advantages with Gla-300

    Adult patient preferences for long-acting ADHD treatments: A discrete choice experiment

    Get PDF
    Background and Objective: Treatment for attention deficit hyperactivity disorder (ADHD) requires a multifaceted approach including psychosocial interventions and pharmacological treatment. This study evaluates preferences for specific attributes associated with different long-acting stimulant treatment among US adults with ADHD. Methods: Patients completed an online, cross-sectional survey, incorporating a discrete choice experiment to assess preferences for attributes. Results: Analyses included 200 adults with ADHD (mean age 33.0 years; 60% self-reporting moderate severity); the mean (SD) Adult ADHD Self-Report Scale-v1.1 score was 45.9 (12.4). Overall, patients valued speed of onset most and risk of rebound least. Three population groups with distinct preferences were identified: side effect-driven (n=69, 35%), quick onset-driven (n=47, 24%) and quick onset and long duration-driven (n=84, 42%). Conclusion: This study shows differences in how adults with ADHD value and assess benefit-risk trade-offs when considering the desired attributes of stimulant treatments, highlighting the importance of patient-physician shared decision-making to optimize the desired benefits of individualized treatment

    Force Characterization and Manufacturing of a Dynamic Unilateral Clubfoot Brace

    Get PDF
    Clubfoot is a musculoskeletal birth defect that is characterized by an inward twisting of an infant’s feet. The current method for correction involves several casts and a bilateral boots-and-bar maintenance brace. This method of maintenance requires 5 years of bracing and has issues with compliance, comfort, and social stigma. CURE International in Kijabe, Kenya is currently using the boots-and-bar brace but is interested in implementing a design that reduces these concerns. Mr. Jerald Cunningham, CPO, designed and is utilizing a unilateral clubfoot maintenance brace, the Cunningham Brace, which he expects will reduce treatment time to 2-3 years, lessen the social stigma, and increase the child’s mobility. However, there is not enough published research on its biomechanics and patient success rates to confirm his findings. The Collaboratory Cunningham Clubfoot Brace project seeks to validate the effectiveness of this design and increase accessibility through force testing and standardized manufacturing. We are working on measuring the biomechanical forces created and applied by the brace with a series of force sensors that are attached to the child’s brace. In addition, a new wrapping process for manufacturing the Cunningham Brace is being developed to increase the productivity and reproducibility of brace manufacturing in Kenya. Along with a clinical study that was started in Kenya, this testing and manufacturing will allow for further understanding of the effectiveness of the Cunningham Brace and provide more research for the medical community for it to potentially be accepted as an alternative clubfoot maintenance brace.https://mosaic.messiah.edu/engr2020/1014/thumbnail.jp

    Dependence of CMI Growth Rates on Electron Velocity Distributions and Perturbation by Solitary Waves

    Full text link
    We calculate growth rates and corresponding gains for RX and LO mode radiation associated with the cyclotron maser instability for parameterized horseshoe electron velocity distributions. The velocity distribution function was modeled to closely fit the electron distribution functions observed in the auroral cavity. We systematically varied the model parameters as well as the propagation direction to study the dependence of growth rates on model parameters. The growth rate depends strongly on loss cone opening angle, which must be less than 90o90^{o} for significant CMI growth. The growth rate is sharply peaked for perpendicular radiation (k=0k_{\parallel} = 0), with a full-width at half-maximum 1.7o1.7^{o}, in good agreement with observed k-vector orientations and numerical simulations. The fractional bandwidth varied between 104^{-4} and 102^{-2}, depending most strongly on propagation direction. This range encompasses nearly all observed fractional AKR burst bandwidths. We find excellent agreement between the computed RX mode emergent intensities and observed AKR intensities assuming convective growth length LcL_c\approx20-40 km and group speed 0.15cc. The only computed LO mode growth rates compatible observed LO mode radiation levels occurred for number densities more than 100 times the average energetic electron densities measured in auroral cavities. This implies that LO mode radiation is not produced directly by the CMI mechanism but more likely results from mode conversion of RX mode radiation. We find that perturbation of the model velocity distribution by large ion solitary waves (ion holes) can enhance the growth rate by a factor of 2-4. This will result in a gain enhancement more than 40 dB depending on the convective growth length within the structure. Similar enhancements may be caused by EMIC waves.Comment: 21 pages, 11 figures. J. Geophys. Res. 2007 (accepted

    BMP9 Protects Septal Neurons from Axotomy-Evoked Loss of Cholinergic Phenotype

    Get PDF
    Cholinergic projection from the septum to the hippocampus is crucial for normal cognitive function and degeneration of cells and nerve fibers within the septohippocampal pathway contributes to the pathophysiology of Alzheimer's disease. Bone morphogenetic protein (BMP) 9 is a cholinergic differentiating factor during development both in vivo and in vitro.To determine whether BMP9 could protect the adult cholinergic septohippocampal pathway from axotomy-evoked loss of the cholinergic phenotype, we performed unilateral fimbria-fornix transection in mice and treated them with a continuous intracerebroventricular infusion of BMP9 for six days. The number of choline acetyltransferase (CHAT)-positive cells was reduced by 50% in the medial septal nucleus ipsilateral to the lesion as compared to the intact, contralateral side, and BMP9 infusion prevented this loss in a dose-dependent manner. Moreover, BMP9 prevented most of the decline of hippocampal acetylcholine levels ipsilateral to the lesion, and markedly increased CHAT, choline transporter CHT, NGF receptors p75 (NGFR-p75) and TrkA (NTRK1), and NGF protein content in both the lesioned and unlesioned hippocampi. In addition, BMP9 infusion reduced bilaterally hippocampal levels of basic FGF (FGF2) protein.These data indicate that BMP9 administration can prevent lesion-evoked impairment of the cholinergic septohippocampal neurons in adult mice and, by inducing NGF, establishes a trophic environment for these cells

    Multiple Lines of Evidence Risk Assessment of Terrestrial Passerines Exposed to PCDFs and PCDDs in the Tittabawassee River Floodplain, Midland, Michigan, USA

    Get PDF
    A site-specific multiple lines of evidence risk assessment was conducted for house wrens (Troglodytes aedon) and eastern bluebirds (Sialia sialis) along the Tittabawassee River downstream of Midland, Michigan, where concentrations of polychlorinated dibenzofurans (PCDFs) and polychlorinated dibenzo-p-dioxins (PCDDs) in flood-plain soils and sediments are greater compared to upstream areas and some of the greatest anywhere in the world. Lines of evidence supporting the population-level assessment endpoints included site-specific dietary- and tissue-based exposure assessments and population productivity measurements during breeding seasons 2005–2007. While a hazard assessment based on site-specific diets suggested that populations residing in the downstream floodplain had the potential to be affected, concentrations in eggs compared to appropriate toxicity reference values (TRVs) did not predict a potential for population-level effects. There were no significant effects on reproductive success of either species. The most probable cause of the apparent difference between the dietary- and tissue-based exposure assessments was that the dietary-based TRVs were overly conservative based on intraperitoneal injections in the ring-necked pheasant. Agreement between the risk assessment based on concentrations of PCDFs and PCDDs in eggs and reproductive performance in both species supports the conclusion of a small potential for population-level effects at this site
    corecore