1,282 research outputs found

    Acoustic analysis of aft noise reduction techniques measured on a subsonic tip speed 50.8 cm (twenty inch) diameter fan

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    Sound data which were obtained during tests of a 50.8 cm diameter, subsonic tip speed, low pressure ratio fan were analyzed. The test matrix was divided into two major investigations: (1) source noise reduction techniques; and (2) aft duct noise reduction with acoustic treatment. Source noise reduction techniques were investigated which include minimizing second harmonic noise by varying vane/blade ratio, variation in spacing, and lowering the Mach number through the vane row to lower fan broadband noise. Treatment in the aft duct which includes flow noise effects, faceplate porosity, rotor OGV treatment, slant cell treatment, and splitter simulation with variable depth on the outer wall and constant thickness treatment on the inner wall was investigated. Variable boundary conditions such as variation in treatment panel thickness and orientation, and mixed porosity combined with variable thickness were examined. Significant results are reported

    An Exploration Of The Relationship Between Transformational Leadership Characterististics And Multicultural Education Practices In Teacher Educators

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    This exploration focused on the relationship of transformational leadership in teacher educators and their multicultural education practices as an avenue to prepare and produce more teachers for the increasingly diverse student population in P-12 Schools. This research was a two-phase sequential mixed method design including quantitative and qualitative data of 21 teacher educators at one Historically Black College and University (Kameron Carolina State University). The data were collected through questionnaires, content analysis, interviews and observations. The two questionnaires utilized were the Multifactor Leadership Questionnaire developed by Bass and Avolio (1995) and the Multicultural Education Questionnaire developed by Johnson and Inoue (2001). Descriptive analyses and the Spearman‟s Rank Correlation Coefficient statistic test was used to analyzed the data. The findings suggest from the quantitative results that there is a moderate positive correlation (Rho=.48) in regards to the relationship between HBCU teacher educator‟s transformational leadership characteristics and multicultural education practices. The qualitative findings suggest underlying factors such as the gender, ethnicity and professional ranking along with the collaboration of faculty members influence the development of HBCUs teacher educators‟ practices in multicultural education

    Bottom‐Up versus Top‐Down Strategies for Morphology Control in Polymer‐Based Biomedical Materials

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    The size and shape of polymer materials is becoming an increasingly important property in accessing new functions and applications of nano-/microparticles in many scientific fields. New synthetic methods have allowed unprecedented capability for the facile fabrication of anisotropic and shape-defined nanomaterials. Bottom-up approaches including: emulsion polymerization techniques, amphiphile self-assembly, and polymerization-induced self-assembly, can lead to polymer particles with precise dimensions in the nanoscale. Top-down methods such as lithographic templating, and 3D printing, have increased the access to unique particle shapes. In this review, these recent developments are appraised and contrasted, with future research directions providing that focus on biomedical applications. Finally, the opportunity available for synergistic combinations of top-down and bottom-up fabrication approaches in realizing previously unattainable architectures and material properties is highlighted

    Teachers’ Beliefs About And Use Of Formative Assessment In The Middle Grades Mathematics Classroom

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    Research abounds on the benefits of formative assessment to both students and teachers. Those benefits include student achievement on summative assessments, self-efficacy of students, students’ regulation of their own learning, and much more. School districts and teachers understand the benefits of formative assessment to students. However, teachers’ beliefs about formative assessment are not always mirrored by their use of it in the classroom (Yan & Cheng, 2015). This case study was designed to examine middle school math teachers’ beliefs about and use of formative assessment in the classroom. The setting for this study was a western North Carolina middle school. This case study utilized a questionnaire, classroom observations and individual semi-structured interviews with data analyzed. Formative Assessment Framework and the Theory of Planned Behavior were the lenses used for this study. The data from this study revealed that teachers’ use of formative assessment in the classroom aligns with their definition of it. However, when applying the definition of formative assessment used in this study, there are gaps in teachers’ use of it

    Acoustic performance of a 50.8-cm (20-inch) diameter variable-pitch fan and inlet. Volume 2: Acoustic data

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    Results from acoustic tests on a 50.8 cm (20 inch) QCSEE Under-the-Wing (UTW) engine, variable pitch fan and inlet simulator are tabulated. Tests were run in both forward and reverse thrust mdoes with a bellmouth inlet, five accelerating inlets (one hardwall and four treated), and four low Mach number inlets (one hardwall and three treated). The 1/3 octave-band acoustic data are presented for the model size on the measured 5.2 m (17.0 ft) arc and also data scaled to full QCSEE size 71:20 on a 152.4 m (500 ft) sideline

    Comparison of Aspergillus species-complexes detected in different environmental settings

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    Purpose: Samples from different environmental sources were screened for the presence of Aspergillus, and the distribution of the different species-complexes was determined in order to understand differences among that distribution in the several environmental sources and which of these species complexes are present in specific environmental settings. Methods: Four distinct environments (beaches, poultries, swineries and hospital) were studied and analyzed for which Aspergillus complexes were present in each setting. After plate incubation and colony isolation, morphological identification was done using macro- and microscopic characteristics. The universal fungal primers ITS1 and ITS4 were used to amplify DNA from all Aspergillus isolates, which was sequenced for identification to species complex level. SPSS v15.0 for Windows was used to perform the statistical analysis. Results: Thirty-nine isolates of Aspergillus were recovered from both the sand beach and poultries, 31 isolates from swineries, and 80 isolates from hospital environments, for a total 189 isolates. Eleven species complexes were found total. Isolates belonging to the Aspergillus Versicolores species-complex were the most frequently found (23.8%), followed by Flavi (18.0%), Fumigati (15.3%) and Nigri (13.2%) complexes. A significant association was found between the different environmental sources and the distribution of the several species-complexes (p<0.001); the hospital environment had a greater variability of species-complexes than other environmental locations (10 in hospital environment, against nine in swine, eight in poultries and seven in sand beach). Isolates belonging to Nidulantes complex were detected only in the hospital environment, whereas the other complexes were identified in more than one setting. Conclusion: Because different Aspergillus complexes have different susceptibilities to antifungal drugs, and different abilities in producing mycotoxins, knowledge of the species-complex epidemiology for each setting may allow preventive or corrective measures to be taken toward decreasing professional workers or patient exposure to those agents

    Patient perceptions and expectations regarding imaging for metastatic disease in early stage breast cancer

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    Abstract Purpose The probability of detecting radiologically evident metastatic disease in asymptomatic women with newly diagnosed operable breast cancer is low. Despite the recommendations of most practice guidelines imaging is still frequently performed. Relatively little is known about what patients believe is important when it comes to radiologic staging. Methods Patients with early stage breast cancer who had completed their definitive breast surgery were surveyed about their personal experiences, perceptions, and expectations on the issue of perioperative imaging for distant metastatic disease. Results Over a 3 month period, 245 women with primary operable breast cancer completed the questionnaire (87.0% response rate) and 80.8% indicated having had at least one imaging test for distant metastatic disease. These were either of the thorax (72.2%), abdomen (55.9%) or skeleton (65.3%) with a total of 701 imaging tests (average of 3.5 tests per patient imaged) performed. Overall, 57.1% indicated that they would want imaging done if the chance of detecting metastases was ≤10%. Although 80.0% of patients indicated that, “doing whatever their doctor recommended” was important to them, 70.4% also noted that they would be uncomfortable if their physician did not order imaging, even if this was in keeping with practice guidelines. Conclusions Most patients with early stage breast cancer recall having imaging tests for distant metastases. Given the choice, most would prefer having imaging performed, even if this is not in line with current guidelines. If patient expectations are, in part, driving excessive imaging, new strategies addressing this are required

    A practical synthesis of a novel DPAGT1 inhibitor, aminouridyl phenoxypiperidinbenzyl butanamide (APPB) for in vivo studies

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    Immunotherapy that targets N-linked glycans has not yet been developed due in large part to the lack of specificity of N-linked glycans between normal and malignant cells. N-Glycan chains are synthesized by the sequential action of glycosyl transferases in the Golgi apparatus. It is an overwhelming task to discover drug-like inhibitors of glycosyl transferases that block the synthesis of specific branching processes in cancer cells, killing tumor cells selectively. It has long been known that N-glycan biosynthesis can be inhibited by disruption of the first committed enzyme, dolichyl-phosphate N-acetylglucosaminephosphotransferase 1 (DPAGT1). Selective DPAGT1 inhibitors have the promising therapeutic potential for certain solid cancers that require increased branching of N-linked glycans in their growth progressions. Recently, we discovered that an anti-Clostridium difficile molecule, aminouridyl phenoxypiperidinbenzyl butanamide (APPB) showed DPAGT1 inhibitory activity with the IC_(50) value of 0.25 μM. It was confirmed that APPB inhibits N-glycosylation of β-catenin at 2.5 nM concentration. A sharp difference between APPB and tunicamycin was that the hemolytic activity of APPB is significantly attenuated (IC_(50) > 200 μM RBC). Water solubility of APPB is >350-times greater than that of tunicamycin (78.8 mg/mL for APPB, 60 min) for in vivo studies (PK/PD, safety profiles, and in vivo efficacy) using animal models. We have refined all steps in the previously reported synthesis for APPB for larger-scale. This article summarizes protocols of gram-scale synthesis of APPB and its physicochemical data, and a convenient DPAGT1 assay

    The impact of several demographic factors on chemistry laboratory anxiety and self-efficacy in students’ first year of university

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    The transition from high school to tertiary education can be a daunting prospect for students. The prospect of laboratories, an unfamiliar environment, for students, can increase levels of anxiety. Moreover, there is a growing body of evidence that suggests that students’ self-efficacy is inversely correlated with students’ anxiety. We surveyed students at the start and end of a semester to evaluate levels of anxiety and self-efficacy in relation to several aspects of the chemistry laboratory. Time management and answering assessed questions are the aspects that contribute to high levels of anxiety and low levels of self-efficacy at the start of semester. Students generally reported lower anxiety and higher self-efficacy at the end of the semester about every aspect probed. These results are of interest to any discipline that offers an unfamiliar learning environment for students as aspects such as time management and answering assessed questions are not discipline specific. We investigated the different aspects of anxiety and self-efficacy in relation to various demographic factors

    Influence of 17β-Estradiol on Gene Expression of Paracoccidioides during Mycelia-to-Yeast Transition

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    BACKGROUND: Paracoccidioides is the causative agent of paracoccidioidomycosis, a systemic mycosis endemic to Latin America. Infection is initiated by inhalation of conidia (C) or mycelial (M) fragments, which subsequently differentiate into yeast (Y). Epidemiological studies show a striking predominance of paracoccidioidomycosis in adult men compared to premenopausal women. In vitro and in vivo studies suggest that the female hormone (17β-estradiol, E(2)) regulates or inhibits M-or-C-to-Y transition. In this study we have profiled transcript expression to understand the molecular mechanism of how E(2) inhibits M-to-Y transition. METHODOLOGY: We assessed temporal gene expression in strain Pb01 in the presence or absence of E(2) at various time points through 9 days of the M-to-Y transition using an 11,000 element random-shear genomic DNA microarray and verified the results using quantitative real time-PCR. E(2)-regulated clones were sequenced to identify genes and biological function. PRINCIPAL FINDINGS: E(2)-treatment affected gene expression of 550 array elements, with 331 showing up-regulation and 219 showing down-regulation at one or more time points (p≤0.001). Genes with low expression after 4 or 12 h exposure to E(2) belonged to pathways involved in heat shock response (hsp90 and hsp70), energy metabolism, and several retrotransposable elements. Y-related genes, α-1,3-glucan synthase, mannosyltransferase and Y20, demonstrated low or delayed expression in E(2)-treated cultures. Genes potentially involved in signaling, such as palmitoyltransferase (erf2), small GTPase RhoA, phosphatidylinositol-4-kinase, and protein kinase (serine/threonine) showed low expression in the presence of E(2), whereas a gene encoding for an arrestin domain-containing protein showed high expression. Genes related to ubiquitin-mediated protein degradation, and oxidative stress response genes were up-regulated by E(2). CONCLUSION: This study characterizes the effect of E(2) at the molecular level on the inhibition of the M-to-Y transition and is indicative that the inhibitory actions of E(2) may be working through signaling genes that regulate dimorphism
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