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91.
Many metals are not strongly adsorbed on DEAE-cellulose from aqueous hydrochloric acid media. However, some metals can be adsorbed on DEAE-cellulose from methanol-hydrochloric acid media. Distribution coefficients of Zn, Cd, Hg(II) and Bi(III), which show pronounced adsorption, are presented as functions of the methanol and the acid concentrations. Differences in the distribution coefficient between the four metals and a considerable number of other metals are large enough to permit good separations on columns. Among the platinum group metals, Pd(II), Ir(IV) and Pt(IV) are adsorbed from the mixed solvents and may be separated from large quantities of base metals such as Fe(III), Co(II), Ni and Cu(II). 相似文献
92.
Cellulose - Stabilization of emulsion using plant-derived nanomaterial has been of great research interest. In this regard, cellulose nanofibers (CNF) showed good potential in conventional emulsion... 相似文献
93.
IPN-type composites consisting of cellulose acetate (CA) and poly(methyl methacrylate; PMMA) were successfully synthesized
in film form. In this synthesis, a mercapto group (SH)-containing CA, CA-MA, was prepared in advance by esterification of
CA with mercaptoacetic acid, and then intercomponent cross-linking between CA-MA and PMMA was attained by thiol–ene polymerization
of methyl methacrylate (MMA) onto the CA-MA substrate. For comparison, polymer synthesis was also attempted to produce a semi-IPN
type of composites comprising CA and cross-linked PMMA, via copolymerization of MMA and ethylene glycol dimethacrylate as
cross-linker in a homogeneous system containing CA solute. Thermal and mechanical properties of thus obtained polymer composites
were investigated by differential scanning calorimetry, dynamic mechanical analysis, and a tensile test, in correlation with
the mixing state of the essentially immiscible cellulosic and methacrylate polymer components. It was shown that the specific
IPN technique using thiol–ene reactions usually resulted in a much better compatibility-enhanced polymer composite, which
exhibited a higher tensile strength and even an outstanding ductility without parallel in any film sample of CA, PMMA, and
their physical blends. 相似文献
94.
The combined approaches of rational design and random mutagenesis were applied to generate a sesquiterpene synthase with an altered activity. Due to the lack of a convenient screen for sesquiterpene synthase activity, a high-throughput dual-activity screen was used by fusing (+)-delta-cadinene synthase to chloramphenicol acetyltransferase (CAT). The gene encoding (+)-delta-cadinene synthase was mutagenized using error-prone PCR. The resulting mutant fusion proteins were screened for CAT activity and altered sesquiterpene selectivity. Twenty-one clones producing (+)-delta-cadinene and germacrene D-4-ol in different ratios were isolated from the library. Analysis using a homology model of (+)-delta-cadinene synthase suggested that the G helix plays a very important role in (+)-delta-cadinene formation. Reconstruction of the G helix using site-directed, saturation mutagenesis yielded a mutant, N403P/L405H, that maintained its specific activity and showed higher selectivity to germacrene D-4-ol in vivo (up to 93%). 相似文献
95.
Akiko Nagata Kazuto Iijima Ryota Sakamoto Yuka Mizumoto Miho Iwaki Masaki Takiwaki Yoshikuni Kikutani Seketsu Fukuzawa Minami Odagi Masayuki Tera Kazuo Nagasawa 《Molecules (Basel, Switzerland)》2022,27(8)
Blood levels of the vitamin D3 (D3) metabolites 25-hydroxyvitamin D3 (25(OH)D3), 24R,25-dihydroxyvitamin D3, and 1α,25-dihydroxyvitamin D3 (1,25(OH)2D3) are recognized indicators for the diagnosis of bone metabolism-related diseases, D3 deficiency-related diseases, and hypercalcemia, and are generally measured by liquid-chromatography tandem mass spectrometry (LC-MS/MS) using an isotope dilution method. However, other D3 metabolites, such as 20-hydroxyvitamin D3 and lactone D3, also show interesting biological activities and stable isotope-labeled derivatives are required for LC-MS/MS analysis of their concentrations in serum. Here, we describe a versatile synthesis of deuterium-labeled D3 metabolites using A-ring synthons containing three deuterium atoms. Deuterium-labeled 25(OH)D3 (2), 25(OH)D3-23,26-lactone (6), and 1,25(OH)2D3-23,26-lactone (7) were synthesized, and successfully applied as internal standards for the measurement of these compounds in pooled human serum. This is the first quantification of 1,25(OH)2D3-23,26-lactone (7) in human serum. 相似文献