503 research outputs found

    A Thematic Analysis Study about Remarriage of Elderly Men in Vietnam

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    Although the phenomenon of remarriage at the later phase of life is well-researched in Western countries, little is known in Asia, including Vietnam. Vietnamese divorced/widowed senior citizens who wished to remarry/re-partner at their old age usually faced criticism and misinterpretation of their actions due to obsolete social beliefs and bias. To explore experiences and perspectives of Vietnamese male senior citizens throughout their process of remarriage, this qualitative research recruited and interviewed six male participants who remarried at the age of 56 to 70. They came from six different provinces and central cities of Vietnam. Semi-structured interviews were conducted face-to-face and via audio and video calls. Thematic analysis was used to extract emerging themes and subthemes. There were five themes identified, which include motivations for remarriage, expectations for remarriage, obstacles of remarriage, support for remarriage, and marriage registration of Vietnamese elderly men.

    Synthesis and NMR-Characterization of Three Quinamide-Based Disaccharide Mimetics with Unusual Cyclohexane twist-Conformation

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    The synthesis of amide-linked disaccharide mimetics has been explored starting with carbohydrate-based amines and a protected quinic acid lactone. Benzyl-2-amino-4,6-Obenzylidene-2-deoxy-α/β-D-glucopyranose (12) and D-glucamine (14) were successfully coupled to give the corresponding quinamides (13 and 15), while the quinoylation of Oacetylated L-fucopyranosyl methylamine (7) failed. The latter was prepared from per-O-acetylL-fucopyranose via the improved multigram scale synthesis of the corresponding per-O-acetylL-fucopyranosyl cyanide (3). Compound 3 was subsequently hydrogenated to yield a mixture of compound 7 and the per-O-acetylated bis-(fucopyranosylmethyl) amine (5). The vicinal coupling constants in the NMR spectra of all quinamide products revealed considerable flexibility of the cyclohexane ring in solution and substantial contributions by twist-chair conformations

    A Carleman-Picard approach for reconstructing zero-order coefficients in parabolic equations with limited data

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    We propose a globally convergent computational technique for the nonlinear inverse problem of reconstructing the zero-order coefficient in a parabolic equation using partial boundary data. This technique is called the "reduced dimensional method". Initially, we use the polynomial-exponential basis to approximate the inverse problem as a system of 1D nonlinear equations. We then employ a Picard iteration based on the quasi-reversibility method and a Carleman weight function. We will rigorously prove that the sequence derived from this iteration converges to the accurate solution for that 1D system without requesting a good initial guess of the true solution. The key tool for the proof is a Carleman estimate. We will also show some numerical examples

    A breakthrough dynamic-osmotic membrane bioreactor/nanofiltration hybrid system for real municipal wastewater treatment and reuse.

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    This study designed a Dynamic-Osmotic membrane bioreactor/nanofiltration (OsMBR/NF) system for municipal wastewater treatment and reuse. Results indicated that a continuously rotating FO module with 60 RPM in Dynamic-OsMBR system could enhance shear stress and reduce cake layer of foulants, leading to higher flux (50%) compared to Traditional-OsMBR during a 40-operation day. A negligible specific reverse salt flux (0.059 G/L) and a water flux of 2.86 LMH were recorded when a mixture of 0.1 M EDTA-2Na/0.1 M Na2CO3/0.9 mM Triton114 functioned as draw solution (DS). It was found that the Dynamic-OsMBR/NF hybrid system could effectively remove pollutants (∼98% COD, ∼99% PO43-P, ∼93% NH4+-N, > 99% suspended solids) from wastewater. In short, this developed system can be considered a breakthrough technology as it successfully minimizes membrane fouling by shear force, and achieves high water quality for reuse by two membrane- barriers
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