903 research outputs found

    Design and Fabrication of a Multifunctional Nano-on-micro Delivery System

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    The treatment of tumours using microbeads for embolization and drug delivery is a widely used, but often ineffective, technique. In this work, we aim to produce microbeads for this application with four main improvements: visibility, target-ability, degradability, and an alternative route for drug loading. We accomplish this through the fabrication of ~100μm diameter microbeads composed of poly(vinyl alcohol) (PVA), iron oxide nanoparticles, and cellulose nanocrystals (CNC) using a custom-designed microchannel system. Characterization demonstrated that microbeads were magnetic, as well as visible under clinical CT. Separately, the dissolution of PVA iron oxide hydrogels exposed to different environmental conditions was studied. Iron release and mass loss was demonstrated, and the weakening of material was confirmed using mechanical testing. This shows the potential for microbeads composed of this material to ‘degrade’ over time. PVA iron oxide CNC microbeads are promising as a multifunctional visualization and delivery system

    Innate immune response to intramammary infection with Serratia marcescens and Streptococcus uberis

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    Streptococcus uberis and Serratia marcescens are Gram-positive and Gram-negative bacteria, respectively, that induce clinical mastitis. Once initial host barrier systems have been breached by these pathogens, the innate immune system provides the next level of defense against these infectious agents. The innate immune response is characterized by the induction of pro-inflammatory cytokines, as well as increases in other accessory proteins that facilitate host recognition and elimination of the pathogens. The objective of the current study was to characterize the innate immune response during clinical mastitis elicited by these two important, yet less well-studied, Gram-positive and Gram-negative organisms. The pro-inflammatory cytokine response and changes in the levels of the innate immune accessory recognition proteins, soluble CD14 (sCD14) and lipopolysaccharide (LPS)-binding protein (LBP), were studied. Decreased milk output, induction of a febrile response, and increased acute phase synthesis of LBP were all characteristic of the systemic response to intramammary infection with either organism. Infection with either bacteria similarly resulted in increased milk levels of IL-1β\beta, IL-8, IL-10, IL-12, IFN-γ\gamma, TNF-α\alpha, sCD14, LBP, and the complement component, C5a. However, the duration of and/or maximal changes in the increased levels of these inflammatory markers were significantly different for several of the inflammatory parameters assayed. In particular, S. uberis infection was characterized by the sustained elevation of higher milk levels of IL-1β\beta, IL-10, IL-12, IFN-γ\gamma, and C5a, relative to S. marcescens infection. Together, these data demonstrate the variability of the innate immune response to two distinct mastitis pathogens

    New Mexico Youth Risk & Resiliency 2015 Survey Results Report: Housing Instability and Health

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    In 2015, for the first time, the NM-YRRS questionnaire included a question on homelessness, or housing status. The question mirrored the homelessness definition of the McKinney-Vento Act, which is used by the New Mexico Public Education Department to identify homeless students. For the purposes of this report, students identified as homeless will be referred to as students in unstable housing. Students living in unstable housing were at significantly increased risk for facing violence, using alcohol, tobacco, and other drugs, suicidal behaviors and other mental health issues and other serious challenges

    Continuum: Selecting Inquiry-Based Experiences to Promote a Deeper Understanding of the Nature of Science

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    Whether explicitly or implicitly, science teachers constantly convey an image of the nature of science (NOS) in their classrooms. The actions of the teacher, how the class is run, and the instructional patterns all convey an image of what authentic science is like. As such, significant attention to inquiry-based instructional practices is required to accurately portray the NOS. However, even teaching through inquiry, while necessary, is insufficient for NOS understanding. This article presents four factors that teachers should consider when teaching the NOS. This article addresses National Science Education Content Standards A and G, and Iowa Teaching Standards 3, 4, and 5

    Brain Circuits of Methamphetamine Place Reinforcement Learning: The Role of the Hippocampus-VTA Loop

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    The reinforcing effects of addictive drugs including methamphetamine (METH) involve the midbrain ventral tegmental area (VTA). VTA is primary source of dopamine (DA) to the nucleus accumbens (NAc) and the ventral hippocampus (VHC). These three brain regions are functionally connected through the hippocampal-VTA loop that includes two main neural pathways: the bottom-up pathway and the top-down pathway. In this paper, we take the view that addiction is a learning process. Therefore, we tested the involvement of the hippocampus in reinforcement learning by studying conditioned place preference (CPP) learning by sequentially conditioning each of the three nuclei in either the bottom-up order of conditioning; VTA, then VHC, finally NAc, or the top-down order; VHC, then VTA, finally NAc. Following habituation, the rats underwent experimental modules consisting of two conditioning trials each followed by immediate testing (test 1 and test 2) and two additional tests 24 h (test 3) and/or 1 week following conditioning (test 4). The module was repeated three times for each nucleus. The results showed that METH, but not Ringer's, produced positive CPP following conditioning each brain area in the bottom-up order. In the top-down order, METH, but not Ringer's, produced either an aversive CPP or no learning effect following conditioning each nucleus of interest. In addition, METH place aversion was antagonized by coadministration of the N-methyl-d-aspartate (NMDA) receptor antagonist MK801, suggesting that the aversion learning was an NMDA receptor activation-dependent process. We conclude that the hippocampus is a critical structure in the reward circuit and hence suggest that the development of target-specific therapeutics for the control of addiction emphasizes on the hippocampus-VTA top-down connection

    Rheumatic fever and rheumatic heart disease among children presenting to two referral hospitals in Harare, Zimbabwe

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    Background. Acute rheumatic fever (ARF) and rheumatic heart disease (RHD) remain significant causes of morbidity and mortality in resource-limited settings. In Zimbabwe ARF/RHD characteristics have not been systematically documented.Objectives. To document cases of ARF/RHD among children presenting at referral hospitals in Harare, Zimbabwe, determine their clinical and echocardiographic characteristics, and identify opportunities for improving care.Methods. A cross-sectional survey was carried out in which consecutive children aged 1 - 12 years presenting with ARF/RHD according to the 2002/3 World Health Organization modified Jones criteria were enrolled.Results. Out of 2 601 admissions and 1 026 outpatient visits over 10 months, 50 children were recruited, including 31 inpatients with ARF/RHD and 19 outpatients with chronic RHD. Among inpatients, 9 had ARF only, 7 recurrent ARF with RHD, and 15 RHD only. The commonest valve lesions were mitral regurgitation (26/31) and aortic regurgitation (11/31). The commonest reason for admission was cardiac failure (22/31). The proportion of ARF/RHD cases among inpatients aged 1 - 12 years was 11.9/1 000. Of the 22 with RHD, 14 (63.6%) presented de novo and 1 had bacterial endocarditis. Among the outpatients, 15 had  cardiac failure while echocardiographic findings included mitral regurgitation (18/19) and aortic regurgitation (5/19). At presentation, 18/26 known cases were on oral penicillin prophylaxis and 7 on  injectable penicillin. Of those on secondary prophylaxis, 68.0% reported taking it regularly.Conclusion. ARF/RHD remains a major problem and cause of hospital admissions in Harare, Zimbabwe. Children often present late with established RHD and cardiac failure. With the majority on oral penicillin, secondary prophylaxis was suboptimal in a resource-limited setting unable to offer valve replacement surgery

    Ethnicity and the Writing of Medieval Scottish history

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    Historians have long tended to define medieval Scottish society in terms of interactions between ethnic groups. This approach was developed over the course of the long nineteenth century, a formative period for the study of medieval Scotland. At that time, many scholars based their analysis upon scientific principles, long since debunked, which held that medieval 'peoples' could only be understood in terms of 'full ethnic packages'. This approach was combined with a positivist historical narrative that defined Germanic Anglo-Saxons and Normans as the harbingers of advances of Civilisation. While the prejudices of that era have largely faded away, the modern discipline still relies all too often on a dualistic ethnic framework. This is particularly evident in a structure of periodisation that draws a clear line between the 'Celtic' eleventh century and the 'Norman' twelfth. Furthermore, dualistic oppositions based on ethnicity continue, particularly in discussions of the law, kingship, lordship and religion

    A Role for Dorsal and Ventral Hippocampus in Inter-Temporal Choice Cost-Benefit Decision Making

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    Previous studies suggest a preferential role for dorsal hippocampus (dHPC) in spatial memory tasks, whereas ventral hippocampus (vHPC) has been implicated in aspects of fear and/or anxiety. In this study, we tested the hypothesis that vHPC may be a critical subregion for performance on a delay-based, cost-benefit decision making task. Rats chose between the two goal arms of a T maze, one containing an immediately available small reward, the other containing a larger reward that was only accessible after a delay. dHPC, vHPC, and complete hippocampal (cHPC) lesions all reduced choice of the delayed high reward (HR) in favor of the immediately available low reward (LR). The deficits were not due to a complete inability to remember which reward size was associated with which arm of the maze. When an equivalent 10-s delay was introduced in both goal arms, all rats chose the HR arm on nearly all trials. The deficit was, however, reinstated when the inequality was reintroduced. Our results suggest an important role for both dHPC and vHPC in the extended neural circuitry that underlies intertemporal choice

    Kiloclips and Millipens: An Introduction to Units of Measure

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    This article presents a physical science activity for introducing units of measure and the role of human beings in deciding units of measure and their standards. These important science ideas are introduced through inquiry, and in a way that makes this activity appropriate for the beginning of the school year. The manner that this activity is done promotes mental engagement, collaboration, and a deeper understanding of the targeted concepts. In doing so, it helps set expectations for the entire course that students will be actively engaged in learning. The activity uses common objects to serve as standards for mass and has students build their own simple balances to teach mass as a property of matter that should later be contrasted with weight. This activity promotes National Science Education Content Standards A, B, E, F, and G, and Iowa Teaching Standards 1, 2, 3, and 5
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