60 research outputs found

    Portfolio As A Teaching Method: A Capstone Project To Promote Recognition Of Professional Growth

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    A reflective portfolio as a capstone assignment was selected to accomplish recognition by teachers completing a science, technology, mathematics, engineering master’s program for elementary teachers about their professional and personal changes and to provide program evaluators additional qualitative data regarding attainment of program goals. As the teachers in the program (N=20) neared the completion of the program, they were required to take a comprehensive look at their experience. This data-driven, reflective portfolio experience showed that the process clarified teachers’ learning in strategies to improve student learning, importance of reflective practice, their role as a teacher leader, dedication to life-long learning and confidence in being an effective professional educator

    Morphologic change in rabbit femoral arteries induced by storage at four degrees Celsius and by subsequent reperfusion

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    AbstractPurpose: Cold-stored arteries function well as microvascular autografts, but little is known of the morphologic changes that occur in them during cold storage or of further changes during reperfusion.Methods: In part A of the study, rabbit femoral arteries were stored at 4° C for up to 6 months. In part B rabbit femoral arteries were stored at 4° C for up to 6 months, inserted as end-to-end autografts into contralateral femoral arteries, and reperfused for 24 hours. Tissue was examined by histologic study, transmission and scanning electron microscopy, histochemical study, immunohistochemical study, and tissue culture.Results: Cell viability declined gradually at 4° C, so that by 4 weeks no viable cells remained. However, the extracellular framework and elastic lamellae remain intact. If cold-stored arteries are reinserted as autografts for 24 hours, this accelerates breakdown of necrotic cells and reduces the thickness of the medial wall and internal elastic lamina but does not alter the extracellular framework.Conclusions: Cold storage results in acellular vascular grafts with intact extracellular frameworks. After 24 hours reperfusion there is no major change to the extracellular framework. (J VASC SURG 1995;22:769-79.

    Effects of an Inquiry-Focused, Content-Intensive Program on Pre-Kindergarten-9th Grade Teachers’ Content Knowledge, Self-Efficacy, and Goals

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    This study describes the effects of an inquiry-focused, contentintensive professional development program on Pre-kindergarten-9th grade teachers’ science and mathematics knowledge, use of classroom based inquiry, improvement in their science teaching self-efficacy and other motivation constructs. This two-and-a-half-year program was designed to meet the needs of teachers in a local urban school district. The professional development in the form of a graduate program intentionally sought to emphasize science and mathematics content knowledge and inquiry teaching. Twenty experimental teacher-participants were involved in the program with twelve additional teachers as a control group. Data collection instruments used for this study included content testing, student test-scores, self-efficacy belief surveys, and behavioral scales. The results of the study indicated greater growth for program participants in the areas of science and mathematics content knowledge. The participants also showed greater increases in science teaching self-efficacy as compared to the teachers in the control group

    Thirteen Moons: Forging Connections in an Ojibwe Community Through Culture Ecology and Management

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    Traditional ecological knowledge and culture represent assets in community-based conservation and development. These assets, however, are often perceived as challenges to conservation and development efforts by external community partners and, perhaps surprisingly, by community actors. The latter realization emerged from the work of a partnership between the Fond du Lac (FDL) Band of Lake Superior Chippewa (Ojibwe) and University of Minnesota Extension. This partnership sought to develop an Extension program to educate Band members about natural resources and improve management of Tribal natural resources by increasing overall understanding of Band members’ interest in these resources

    The mitochondrial permeability transition in cell death: a common mechanism in necrosis, apoptosis and autophagy

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    AbstractUsing confocal microscopy, onset of the mitochondrial permeability transition (MPT) in individual mitochondria within living cells can be visualized by the redistribution of the cytosolic fluorophore, calcein, into mitochondria. Simultaneously, mitochondria release membrane potential-indicating fluorophores like tetramethylrhodamine methylester. The MPT occurs in several forms of necrotic cell death, including oxidative stress, pH-dependent ischemia/reperfusion injury and Ca2+ ionophore toxicity. Cyclosporin A (CsA) and trifluoperazine block the MPT in these models and prevent cell killing, showing that the MPT is a causative factor in necrotic cell death. During oxidative injury induced by t-butylhydroperoxide, onset of the MPT is preceded by pyridine nucleotide oxidation, mitochondrial generation of reactive oxygen species, and an increase of mitochondrial free Ca2+, all changes that promote the MPT. During tissue ischemia, acidosis develops. Because of acidotic pH, anoxic cell death is substantially delayed. However, when pH is restored to normal after reperfusion (reoxygenation at pH 7.4), cell death occurs rapidly (pH paradox). This killing is caused by pH-dependent onset of the MPT, which is blocked by reperfusion at acidotic pH or with CsA. In isolated mitochondria, toxicants causing Reye’s syndrome, such as salicylate and valproate, induce the MPT. Similarly, salicylate induces a CsA-sensitive MPT and killing of cultured hepatocytes. These in vitro findings suggest that the MPT is the pathophysiological mechanism underlying Reye’s syndrome in vivo. Kroemer and coworkers proposed that the MPT is a critical event in the progression of apoptotic cell death. Using confocal microscopy, the MPT can be directly documented during tumor necrosis factor-α induced apoptosis in hepatocytes. CsA blocks this MPT and prevents apoptosis. The MPT does not occur uniformly during apoptosis. Initially, a small proportion of mitochondria undergo the MPT, which increases to nearly 100% over 1–3 h. A technique based on fluorescence resonance energy transfer can selectively reveal mitochondrial depolarization. After nutrient deprivation, a small fraction of mitochondria spontaneously depolarize and enter an acidic lysosomal compartment, suggesting that the MPT precedes the normal process of mitochondrial autophagy. A model is proposed in which onset of the MPT to increasing numbers of mitochondria within a cell leads progressively to autophagy, apoptosis and necrotic cell death

    Pathogenicity and immunogenicity of attenuated, nef-deleted HIV-1 strains in vivo

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    In efforts to develop an effective vaccine, sterilizing immunity to primate lentiviruses has only been achieved by the use of live attenuated viruses carrying major deletions in nef and other accessory genes. Although live attenuated HIV vaccines are unlikely to be developed due to a myriad of safety concerns, opportunities exist to better understand the correlates of immune protection against HIV infection by studying rare cohorts of long-term survivors infected with attenuated, nef-deleted HIV strains such as the Sydney blood bank cohort (SBBC). Here, we review studies of viral evolution, pathogenicity, and immune responses to HIV infection in SBBC members. The studies show that potent, broadly neutralizing anti-HIV antibodies and robust CD8+ T-cell responses to HIV infection were not necessary for long-term control of HIV infection in a subset of SBBC members, and were not sufficient to prevent HIV sequence evolution, augmentation of pathogenicity and eventual progression of HIV infection in another subset. However, a persistent T-helper proliferative response to HIV p24 antigen was associated with long-term control of infection. Together, these results underscore the importance of the host in the eventual outcome of infection. Thus, whilst generating an effective antibody and CD8+ T-cell response are an essential component of vaccines aimed at preventing primary HIV infection, T-helper responses may be important in the generation of an effective therapeutic vaccine aimed at blunting chronic HIV infection

    Plastic Laminate Pulsed Power Development

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    The desire to move high-energy Pulsed Power systems from the laboratory to practical field systems requires the development of compact lightweight drivers. This paper concerns an effort to develop such a system based on a plastic laminate strip Blumlein as the final pulseshaping stage for a 600 kV, 50ns, 5-ohm driver. A lifetime and breakdown study conducted with small-area samples identified Kapton sheet impregnated with Propylene Carbonate as the best material combination of those evaluated. The program has successfully demonstrated techniques for folding large area systems into compact geometry's and vacuum impregnating the laminate in the folded systems. The major operational challenges encountered revolve around edge grading and low inductance, low impedance switching. The design iterations and lessons learned are discussed. A multistage prototype testing program has demonstrated 600kV operation on a short 6ns line. Full-scale prototypes are currently undergoing development and testing

    Novel Cell- and Tissue-Based Assays for Detecting Misfolded and Aggregated Protein Accumulation Within Aggresomes and Inclusion Bodies

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    Aggresomes and related inclusion bodies appear to serve as storage depots for misfolded and aggregated proteins within cells, which can potentially be degraded by the autophagy pathway. A homogenous fluorescence-based assay was devised to detect aggregated proteins inside aggresomes and inclusion bodies within an authentic cellular context. The assay employs a novel red fluorescent molecular rotor dye, which is essentially nonfluorescent until it binds to structural features associated with the aggregated protein cargo. Aggresomes and related structures were generated within cultured cells using various potent, cell permeable, proteasome inhibitors: MG-132, lactacystin, epoxomicin and bortezomib, and then selectively detected with the fluorescent probe. Employing the probe in combination with various fluorescein-labeled primary antibodies facilitated co-localization of key components of the autophagy system (ubiquitin, p62, and LC3) with aggregated protein cargo by fluorescence microscopy. Furthermore, cytoplasmic aggregates were highlighted in SK-N-SH human neuroblastoma cells incubated with exogenously supplied amyloid beta peptide 1–42. SMER28, a small molecule modulator of autophagy acting via an mTOR-independent mechanism, prevented the accumulation of amyloid beta peptide within these cells. The described assay allows assessment of the effects of protein aggregation directly in cells, without resorting to the use of non-physiological protein mutations or genetically engineered cell lines. With minor modification, the assay was also adapted to the analysis of frozen or formalin-fixed, paraffin-embedded tissue sections, with demonstration of co-localization of aggregated cargo with β-amyloid and tau proteins in brain tissue sections from Alzheimer’s disease patients
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