2,564 research outputs found
Focusing of phase change microparticles for local heat transfer enhancement in laminar flows
Phase change material (PCM) suspensions have received wide spread attention for increased thermal storage in various thermal systems such as heat sinks for electronics and solar thermal applications. To achieve further heat transfer enhancement, this paper investigates the effect of focusing micron-sized phase-change particles (PCMs) to a layer near the heated wall of a parallel plate channel. A numerical model for fully-developed laminar flow with a constant heat flux applied to one wall is developed. Melting of the focused PCMs is incorporated using a temperature-dependent effective heat capacity. The effect of channel height, height of the focused PCM stream, heat flux, and fluid properties on the peak local Nusselt number (Nu∗) and the averaged Nusselt number over the melting length (Nu[subscript melt]) are investigated. Compared to the thermally-developed Nusselt number for this geometry (Nuo = 5.385), Nu[subscript melt]and Nu∗ enhancements of 8% and 19% were determined, respectively. The local heat transfer performance is optimized when the PCMs are confined to within 30% of the channel height. The present work provides an extended understanding of local heat transfer characteristics during melting of flowing PCM suspensions, and offers a new method for enhancing heat transfer performance in various thermal-fluidic systems
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Navigating Home Language Practice for Children With Disabilities: Insights From Korean-American Mothers\u27 Online Communications
This study explores the home language practice (HLP) of Korean-American mothers with children who have developmental disabilities, including autism spectrum disorder. Data was collected from an online forum where these mothers discussed their experiences and decision-making processes following their child\u27s diagnosis. Thematic analysis was conducted on the collected data to identify and develop themes related to their experiences. The study\u27s framework is based on family-centered practices, emphasizing the importance of equal partnerships, cultural responsiveness, and information sharing between families and early intervention and early childhood special education (EI/ECSE) professionals. Factors that influence HLP decisions include mothers\u27 perceptions of disabilities, professional advice, and children’s intervention progress. The study highlights the vital role of EI/ECSE professionals in sharing current research findings, their experiences with culturally and linguistically diverse (CLD) families, and the long-term outcomes of families that chose bilingual or single-language environments. By offering this information, professionals can assist parents in making informed decisions about their child\u27s HLP. Furthermore, the study emphasizes the value of online communities for CLD parents and the need for professionals to engage with these communities to provide accurate information on bilingualism for children with disabilities. Collaborating with ethnolinguistic communities and establishing parent support groups can create a nurturing environment for parents navigating EI/ECSE services for their children
Comparison of maternal health services and indicators in three districts of the Volta Region, Ghana
Background: Ghana’s maternal mortality ratio continues to decline, but is not expected to meet the Millennium Development Goal (MDG) 5 target. The Ghana Health Service and Ministry of Health have displayed a high commitment to the improvement of maternal health in the country. One of the most recent partnerships directed at this is with the Korea International Cooperation Agency.Methods: This study was conducted among women between ages 15 and 49 resident in Keta Municipal, Ketu North and Ketu South districts in the Volta Region of Ghana who were pregnant or who had children aged less than five. Ethical approval was obtained from the Ghana Health Service Ethical Review Committee. Data were collected using questionnaires, entered into Stata version 12 and analyzed using frequency distribution and assessment of means. Comparisons among districts were conducted using chi square test and one way analysis of variance (ANOVA).Results: The study covered 630 women whose mean age was 28.4 years. Almost all participants (99.1%) from Ketu North knew where to obtain family planning services. Use of modern contraception was highest in Ketu North with 31% of respondents using a modern method. Delivery in a health facility was highest in Keta Municipal (62.3%) with overall institutional delivery being 57.6%. Delivery by a skilled birth attendant (SBA) was also highest in Keta Municipal.Conclusion: Indicators used to assess maternal health services show a coverage of over 50% but we need to improve institutional delivery, use of modern contraception and education about danger signs in pregnancy. Funding: This work was supported by the National Research Foundation of Korea Grant funded by the Korean Government (NRF-2013S1A5B8A01055336) and the Korea International Cooperation Agency(2013).Keywords: Maternal Health, Ghana, Volta Region, Family Planning, Skilled Birth Attendan
Palladium Catalysts for Dehydrogenation of Ammonia Borane with Preferential B−H Activation
Cationic Pd(II) complexes catalyzed the dehydrogenation of ammonia borane in the most efficient manner with the release of 2.0 equiv of H_2 in less than 60 s at 25 °C. Most of the hydrogen atoms were obtained from the boron atom of the ammonia borane. The first step of the dehydrogenation reaction was elaborated using density functional theory calculations
CT, MR, and Angiography Findings of a Solitary Fibrous Tumor of the Larynx: a Case Report
This report details the CT, MR, and angiography findings of a solitary fibrous tumor involving the larynx of a 34-year-old man. A precontrast CT scan revealed a well-defined isodense mass in the submucosal region of the supraglottic larynx. The tumor appeared as a mixed intensity lesion on the T1- and T2-weighted MR images. A T2-weighted MR image showed a central, round, and low signal intensity area within the mass. For both the CT and MR images, the mass demonstrated heterogeneous enhancement following the administration of contrast material. The angiography showed a hypervascular tumor with heterogeneous persistent staining
Isolation and characterization of differentially expressed genes in the mycelium and fruit body of Pleurotus ostreatus
The fruiting body of one of the most widely cultivated mushrooms, the oyster mushroom (Pleurotus ostreatus) is highly interesting, both commercially and scientifically. In the present study, we performed comparative proteomic profiling of P. ostreatus at two unique developmental stages; mycelium and fruit body, using two-dimensional gel electrophoresis (2-DE). Seven hundred fourteen (714) spots were detected and 29 spots (showing a high level of difference in their expressions) were identified by tandem mass spectrometry and basic local alignment search tool (BLAST) searching of an expressed sequence tag (EST) database of P. ostreatus. Among them, six proteins (putative fatty acid oxygenase, heat shock sks2, PriA homologue, Ap-1 like transcription factor YAP7, mung bean seed albumin, and C2H2 Zinc finger domain protein) and one protein (peroxisomal biogenesis factor 6) showed increased expression levels at the fruiting process and the mycelial stage, respectively. Through reverse transcriptase-polymerase chain reaction analysis, priA homologue and AP-1 like transcription factor yap7 showed gradually increased expression from mycelia to fruit body, whereas putative fatty acid oxygenase and heat shock protein sks2 were expressed only in the fruit body. These results provide useful information for future studies of mushroom development of P. ostreatus.Keywords: Developmental stage, mushroom fruiting, Pleurotus ostreatus, protein, two-dimensional gel electrophoresisAfrican Journal of Biotechnology Vol. 12(24), pp. 3790-379
Chemical composition and anti-inflammatory effects of essential oil from Hallabong flower
A number of essential oils derived from plants are claimed to have several medicinal functions, including anti-cancer and anti-inflammation effects. However, the chemical composition and biological activities of flower-derived components have
not been sufficiently characterized. Therefore, we investigated the composition of essential oils from Hallabong flower
[(Citrus unshiu Marcov × Citrus sinensis
Osbeck) × Citrus reticulata Blanco] and their anti-inflammatory effects. Hydro-dist
illed essential oils (HEOs) were analyzed using gas chromatography–mass spectrometry (GC–MS). In total, 21 components were identified, representing more than 98 % of the oils, with sabinene (34.75 %), linalool (14.77 %), β-ocimene (11.07 %), 4-terpineol (9.63 %), L-limonene (5.88 %), and γ-terpinene (4.67 %) as the main components. In the present study, we also investigated the anti-inflammatory effects of HEOs on lipopolysaccharide (LPS)-stimulated RAW 26
4.7 macrophage cells. HEOs were found to
inhibit nitric oxide (NO) and prostaglandin E2 (PGE2) production and to suppress the LPS-
induced expression of cyclooxygenase-2 (COX-2) protein. In addition, HEOs downregulated the production of the inflammatory cytokines, tumor necrosis factor (TNF)-α, interleukin (IL)-6, and IL-1
β(IC50 values are 0.05 %, 0.02 %, and 0.01 %, respectively). On the basis of these
results, we suggest that HEOs can be consid
ered potential anti-inflammatory candidates for therapeutic use in humans
Three newly recorded plants of South Korea: Muhlenbergia ramosa (Hack. ex Matsum.) Makino, Dichanthelium acuminatum (Sw.) Gould & C.A. Clark and Rottboellia cochinchinensis (Lour.) Clayton
AbstractThree new Poaceae species are reported in South Korea. Muhlenbergia ramosa was found in Boryeong-si, Iksan-si, Jangsu-gun and Gwangju. Dichanthelium acuminatum and Rottboellia cochinchinensis were found in Jeonju-si, Jeollabuk-do and Seogwipo-si, Jeju-do which were thought to be alien species. Genus Dichanthelium and Rottboellia are newly reported in South Korea. Muhlenbergia ramosa was thought to be native to Korea
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