113 research outputs found
The Impact of Internationalization on Teaching and Learning: A Qualitative Exploratory Extreme Case Study in a Business PhD Program at an American Public Research University
Ph.D. Thesis. University of Hawaiʻi at Mānoa 2018
Chinese Doctoral Student Socialization in the United States: A Qualitative Study
Although international students annually contribute billions of dollars to the US economy, meaningful intercultural interaction between international students, peers, and faculty is often missing at US host campuses. Feelings of isolation, loneliness, and alienation are pervasive among international students at US campuses; these feelings can negatively impact students’ ability to engage in academic and social activities. This study is designed to explore how Chinese doctoral students socialize into a US doctoral program and how they perceive their socialization experiences. Using qualitative methods, we highlight student experiences and isolate areas of misalignment in the educational process
Behavior-oriented numerical modeling of nearshore oceanic current and application on sea harbor
590-602The West Guangdong longshore current (WG current) is a unique oceanic current system. Plenty of field survey datasets indicated that it flows uni-directionally from north-east to south-west in the entire year even during the south-west monsoon season. At present, the natural formation mechanism of the WG current remains controversial, and the traditional process-oriented modeling method could not deal with the dilemma of the scaling mismatch between the regional ocean circulation (several thousand kilometers) and harbor structure (several hundred meters). To solve this problem, in this paper, a behavior-oriented modeling concept was developed, wherein the contribution of the WG current was considered by incorporating additional net flow flux in the hydrodynamic model to separate it from the tidal currents. Through rigorous validations according to the site observed datasets, the proposed modeling concept was found to have good precision. Using the Jida Harbor as a real-life case, the modeling results showed that after the combination of the tidal current and WG current, the westward cross-flow speed in the approach channel could exceed 0.5 m/s, and at the harbor entrance the WG current induces an intense local circulation cell while ebbing, which may bring in additional maneuver risk to the ships
Dipotassium samarium(III) molybdate(VI) phosphate(V), K2Sm(MoO4)(PO4)
The title compound, K2Sm(MoO4)(PO4), has been prepared under atmospheric conditions using a high temperature solution growth (HTSG) method. The structure of K2Sm(MoO4)(PO4) is isotypic with other A
2
M(MoO4)(PO4) compounds, where A = Na or K, and M = trivalent rare earth cation. It can be described as being built up from two-dimensional anionic layers with composition [Sm(MoO4)(PO4)]2− that are stacked along the c axis and are interconnected by K+ cations which are in an eightfold coordination by O atoms. The SmO8, MoO4 and PO4 polyhedra exhibit 2 symmetry
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Structure and regulation of ZCCHC4 in m6A-methylation of 28S rRNA.
N6-methyladenosine (m6A) modification provides an important epitranscriptomic mechanism that critically regulates RNA metabolism and function. However, how m6A writers attain substrate specificities remains unclear. We report the 3.1 Å-resolution crystal structure of human CCHC zinc finger-containing protein ZCCHC4, a 28S rRNA-specific m6A methyltransferase, bound to S-adenosyl-L-homocysteine. The methyltransferase (MTase) domain of ZCCHC4 is packed against N-terminal GRF-type and C2H2 zinc finger domains and a C-terminal CCHC domain, creating an integrated RNA-binding surface. Strikingly, the MTase domain adopts an autoinhibitory conformation, with a self-occluded catalytic site and a fully-closed cofactor pocket. Mutational and enzymatic analyses further substantiate the molecular basis for ZCCHC4-RNA recognition and a role of the stem-loop structure within substrate in governing the substrate specificity. Overall, this study unveils unique structural and enzymatic characteristics of ZCCHC4, distinctive from what was seen with the METTL family of m6A writers, providing the mechanistic basis for ZCCHC4 modulation of m6A RNA methylation
Mitigation of premature ovarian failure by over-expression of lentivirus vector-mediated Wilms tumor-suppressor gene
Purpose: To investigate the effect of WT1(Wilms tumor-suppressor gene) overexpression on premature ovarian failure (POF)-mediated ovarian dysfunction.Methods: Three mice groups were used: control group (untreated mice), POF group (mice sterilized by intravenous injection of cyclophosphamide and busulfan), and POF-LV(lentiviral vector)GFP(green fluorescent protein)WT1 group (POF mice given intra-ovarian microinjection of LVGFPWT1, a WT1overexpressing lentiviral vector, one week after sterilization). Real time-PCR was employed to analyze in vitro WT1 overexpression levels. Overall ovarian function was measured by hormonal assay, H & E staining, and immuno-histochemical techniques.Results: Overexpression of WT1 in mice models of POF alleviated ovarian granulosa cell (GC) damage, increased ovary weight, and significantly increased follicular number (p < 0.05). Radioimmunoassays revealed reduction in plasma estradiol (E2) and follicle-stimulating hormone (FSH, p < 0.05). However, results from immune-histochemical assays showed reduced Bax expression levels, and increased expression of Bcl-2 in WTI-overexpression mice, relative to POF mice.Conclusion: Overexpression of WT1 may stimulate repair of ovarian tissue while improving endocrine function by inhibiting ovarian cell apoptosis signaling pathway in POF mice.Keywords: Premature ovarian failure, Wilms tumor suppressor gene, Chemotherapy, Apoptosis, Estradio
Lithium samarium polyphosphate, LiSm(PO3)4
The mixed-metal rare-earth polyphosphate LiSm(PO3)4 consists of a three-dimensional framework in which zigzag [(PO3)n]n− chains with a periodicity of four PO4 tetrahedra are connected through Li+ and Sm3+ ions (both with 2. symmetry)
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A DNA aptamer for binding and inhibition of DNA methyltransferase 1.
DNA methyltransferases (DNMTs) are enzymes responsible for establishing and maintaining DNA methylation in cells. DNMT inhibition is actively pursued in cancer treatment, dominantly through the formation of irreversible covalent complexes between small molecular compounds and DNMTs that suffers from low efficacy and high cytotoxicity, as well as no selectivity towards different DNMTs. Herein, we discover aptamers against the maintenance DNA methyltransferase, DNMT1, by coupling Asymmetrical Flow Field-Flow Fractionation (AF4) with Systematic Evolution of Ligands by EXponential enrichment (SELEX). One of the identified aptamers, Apt. #9, contains a stem-loop structure, and can displace the hemi-methylated DNA duplex, the native substrate of DNMT1, off the protein on sub-micromolar scale, leading for effective enzymatic inhibition. Apt. #9 shows no inhibition nor binding activity towards two de novo DNMTs, DNMT3A and DNMT3B. Intriguingly, it can enter cancer cells with over-expression of DNMT1, colocalize with DNMT1 inside the nuclei, and inhibit the activity of DNMT1 in cells. This study opens the possibility of exploring the aptameric DNMT inhibitors being a new cancer therapeutic approach, by modulating DNMT activity selectively through reversible interaction. The aptamers could also be valuable tools for study of the functions of DNMTs and the related epigenetic mechanisms
Scheelite-type NaEr(MoO4)2
Explorations of the A
1+–RE
3+–Mo6+–O2− (A
1+ is an alkali metal cation, RE
3+ is a rare-earth metal cation) quaternary systems prepared by the high-temperature solution growth method led to the title structure, sodium erbium bis(molybdate), NaEr(MoO4)2. It is isostructural to the scheelite structure (CaWO4) and is composed of [MoO4]2− tetrahedra with symmetry and [(Na/Er)O8]14− polyhedra. The [(Na/Er)O8]14− polyhedron is a distorted tetragonal antiprism, also with symmetry, with statistically mixed Na/Er atoms at its centre. There are two sets of Na/Er—O bond lengths [2.420 (4) and 2.435 (3) Å], but just one set of Mo—O bond lengths [1.774 (4) Å]
BPTF promotes tumor growth and predicts poor prognosis in lung adenocarcinomas.
BPTF, a subunit of NURF, is well known to be involved in the development of eukaryotic cell, but little is known about its roles in cancers, especially in non-small-cell lung cancer (NSCLC). Here we showed that BPTF was specifically overexpressed in NSCLC cell lines and lung adenocarcinoma tissues. Knockdown of BPTF by siRNA significantly inhibited cell proliferation, induced cell apoptosis and arrested cell cycle progress from G1 to S phase. We also found that BPTF knockdown downregulated the expression of the phosphorylated Erk1/2, PI3K and Akt proteins and induced the cleavage of caspase-8, caspase-7 and PARP proteins, thereby inhibiting the MAPK and PI3K/AKT signaling and activating apoptotic pathway. BPTF knockdown by siRNA also upregulated the cell cycle inhibitors such as p21 and p18 but inhibited the expression of cyclin D, phospho-Rb and phospho-cdc2 in lung cancer cells. Moreover, BPTF knockdown by its specific shRNA inhibited lung cancer growth in vivo in the xenografts of A549 cells accompanied by the suppression of VEGF, p-Erk and p-Akt expression. Immunohistochemical assay for tumor tissue microarrays of lung tumor tissues showed that BPTF overexpression predicted a poor prognosis in the patients with lung adenocarcinomas. Therefore, our data indicate that BPTF plays an essential role in cell growth and survival by targeting multiply signaling pathways in human lung cancers
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