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101.
102.
Nakayama Masanobu Nishimura Norimitsu Kondo Yuki Takeda Hayami Kasuga Toshihiro 《Journal of Solid State Electrochemistry》2017,21(4):1137-1143
Journal of Solid State Electrochemistry - We demonstrate the Laplace transform (LT) impedance technique for measuring electrochemical lithiation and delithiation in the two-phase system of spinel... 相似文献
103.
Oligosaccharides in therapeutic recombinant antibodies play important roles in regulation of various biological functions. To monitor the glycosylation profiles of antibody pharmaceuticals in the manufacturing process, a highly sensitive and specific method is required. We extended partial-filling techniques using lectins and exoglycosidases in capillary electrophoresis for the characterization of 8-aminopylene-1,3,6-trisulfonic acid labeled N-linked oligosaccharides derived from the therapeutic antibody rituximab. In the lectin-filling method, Galb1–4GlcNAc-specific Erythrina cristagali agglutinin, a1, 6-linked Fuc-specific Aleuria aurantia lectin and Neu5Aca2–3Gal-specific Maackia amurensis lectin were used. The oligosaccharides migrated through the lectin plug during separation; the changes in separation profiles were observed according to the interaction with the lectins. The glycosidase-filling method allowed rapid digestion as suggested by the electropherograms. Partial-filling CE methods can avoid tedious hands-on procedures such as overnight incubation and optimization reaction condition with lectins and exoglycosidases. Combination of these partial-filling capillary electrophoresis methods makes the characterization of oligosaccharide profiles of therapeutic antibodies easier and faster. 相似文献
104.
Potential-dependent adsorption and transfer of poly(diallyldialkylammonium) ions at the nitrobenzene|water interface 总被引:1,自引:0,他引:1
Zhang L Kitazumi Y Kakiuchi T 《Langmuir : the ACS journal of surfaces and colloids》2011,27(21):13037-13042
Electrochemically driven adsorption and partition of a series of poly(diallyldialkylammonium) ions (PDADAA(+): alkyl = methyl, ethyl, propyl, and butyl) at the nitrobenzene (NB)|water (W) interface have been studied using voltammetry and electrocapillary measurements. When the phase-boundary potential, Δφ, that is, the inner potential of the W phase referred to that of the NB phase, is negative, poly(diallyldimethylammonium) (PDADMA(+)) shows little surface activity. The scanning of Δφ in the positive direction induces, first, the adsorption of PDADMA(+) at the interface and, then, the desorption of adsorbed PDADMA(+) ions into the NB phase, followed by the diffusion-limited transfer of PDADMA(+) from W to NB. The elongation of the dialkyl chains gives the stronger surface activity of PDADAA(+) even when Δφ < 0. The PDADAA(+) polyions studied are only slightly more hydrophilic than the corresponding monomers. However, the polycationic character of PDADAA(+) renders the adsorption, desorption, and ion transfer strongly dependent on Δφ and gives rise to unusual, M-shaped electrocapillary curves. The interplay of adsorption-desorption and ion transfer of PDADAA(+) ions induces the electrochemical instability of the interface and the emulsion formation on the NB side of the interface. 相似文献
105.
Cotton cellulose subjected to a dilute aqueous formic acid solution, at acid concentrations up to 1% (w/w), under hydrothermal conditions in a semi-batch reactor was converted into glucose and oligomers with lower degrees of polymerizations (DP). After heating at 250 °C for 60 min in 0.1% (w/w) aqueous formic acid solution, yields of glucose and total sugar with DP = 1 to 9 were 36.6 and 83.8% (100 × gC/gC of initial cotton sample), respectively, and 5-hydroxymethylfurfural was almost as low as 1%. The yields of glucose and oligomers were significantly improved by adding the acid. The reaction was represented by first-order reaction kinetics with regard to (1 ?C x) where x is the conversion based on the total sugar or glucose yield. At 250 °C, the differences in the rate constants (k ? k water) were proportional to the square root of formic acid concentration. 相似文献
106.
Min JZ Suzuki Y Tomiyasu Y Jin D Higashi T Lee YI Toyo'oka T 《Rapid communications in mass spectrometry : RCM》2011,25(19):2911-2922
With Boc-Asn-GlcNAc as a basic structure, four permanently positively charged kinds of new acceptors (GP-Boc-Asn-GlcNAc, GT-Boc-Asn-GlcNAc, HMP-Boc-Asn-GlcNAc, MPDPZ-Boc-Asn-GlcNAc) and five kinds of similar structure acceptors (2-PA-Boc-Asn-GlcNAc, 3-PA-Boc-Asn-GlcNAc, 4-PA-Boc-Asn-GlcNAc, HP-Boc-Asn-GlcNAc, PDPZ-Boc-Asn-GlcNAc) were synthesized as acceptors for the resolution of oligosaccharides in glycopeptides. The synthesized acceptors enzymatically reacted with Disialo-Asn (donor) in the presence of Endo-M. The reaction yields of each transglycosylation product were not obvious, because we do not have all the authentic Disialo-Asn-Boc-acceptors. Therefore, we used the peak area of the transglycosylation product detected by mass spectrometry and evaluated the utility of each acceptor. Among the Boc-Asn-GlcNAc acceptors, the positively charged MPDPZ derivative peak area was the highest, MPDPZ-Boc-Asn-GlcNAc with a positively charged structure showed about a 2.2 times greater sensitivity of the transglycosylation product compared to the conventional fluorescence acceptor DBD-PZ-Boc-Asn-GlcNAc. As a result, the MPDPZ-Boc-Asn-GlcNAc acceptor was suitable for the transglycosylation reaction with Endo-M. The development of a qualitative determination method for the N-linked oligosaccharides in glycoproteins was attempted by combination of the transglycosylation reaction and semi-micro high-performance liquid chromatography/electrospray ionization quadrupole time-of-flight tandem mass spectrometry (HPLC/ESI-QTOF-MS/MS). The asparaginyl-oligosaccharides in glycoproteins, liberated by treatment with Pronase E, were separated, purified and labeled with positively charged MPDPZ. The resulting derivatives were separated by a semi-micro HPLC system. The eluted N-linked oligosaccharide derivatives were then introduced into a QTOF-MS instrument and sensitively detected in the ESI(+) mode. Various fragment ions based on the carbohydrate units appeared in the MS/MS spectra. Among the peaks, m/z 782.37 corresponding to MPDPZ-Boc-Asn-GlcNAc is the most important one for identifying the asparaginyl-oligosaccharides. Disialo-Asn-Boc-MPDPZ was easily identified by the selected-ion chromatogram at m/z 782.37 by MS/MS detection. Therefore, the identification of N-linked oligosaccharides in glycoproteins seems to be possible by the proposed semi-micro HPLC separations followed by the QTOF-MS/MS detection. Furthermore, several oligosaccharides in ovalbumin and ribonuclease B were successfully identified by the proposed procedure. 相似文献
107.
Using a classical simulation protocol for nonlinear optical signals, we predict the two-dimensional (2D) spectra of water near a monolayer of [1,2-dimytristoyl-sn-glycero-3-phosphatidylcholine] (DMPC) generated by three IR probe pulses followed by one visible probe pulse. Sum-frequency-generation 1D spectra show two peaks of the OH stretch representing two environments: near-bulk water nonadjacent to DMPC and top-layer water adjacent to DMPC. These peaks create a 2D pattern in the fourth-order signal. The asymmetric cross-peak pattern with respect to the diagonal line is a signature of coherence transfer from the higher- to the lower-frequency modes. The nodal lines in the imaginary part of the 2D spectrum show that the near-bulk water has fast spectral diffusion resembling that of bulk water despite the orientation by the strong electrostatic field of DMPC. The top-layer water has slower spectral diffusion. 相似文献
108.
Lee VY Ito Y Yasuda H Takanashi K Sekiguchi A 《Journal of the American Chemical Society》2011,133(13):5103-5108
The reaction of 3,4-dichlorotetragermetene derivative 2 with Na(2)[Fe(CO)(4)] in THF produced a (tetragermacyclobutadiene)tricarbonyliron complex, [{η(4)-((t)Bu(2)MeSi)(4)Ge(4)}]Fe(CO)(3)4, which has a slightly folded Ge(4) ring perhaptocoordinated to the Fe center. Structural and spectral characteristics of 4 show a remarkable π-donating ability of the tetragermacyclobutadiene ligand toward the transition metal, surpassing that of tetrasilacyclobutadiene and cyclobutadiene ligands. Reduction of 2 with KC(8) resulted in exclusive formation of the dipotassium salt of the tetragermacyclobutadiene dianion derivative 3(2-)·[K(+)(thf)(2)](2), representing a rare example of a 6π-electron compound that, on the basis of its structural and magnetic properties, was recognized as a nonaromatic species. Reaction of 3(2-)·[K(+)(thf)(2)](2) with CpCoI(2)(PPh(3)) produced a (cyclopentadienyl)(tetragermacyclobutadiene)cobalt complex, [{η(4)-((t)Bu(2)MeSi)(4)Ge(4)}]CoCp 7, as the first example of a sandwich compound featuring an all-germanium-containing cyclic polyene ligand. 相似文献
109.
Yuki Nagao Yuzuru Imai Jun Matsui Tomoyuki Ogawa Tokuji Miyashita 《The Journal of chemical thermodynamics》2011,43(4):613-616
We synthesized seven partially protonated poly(aspartic acids)/sodium polyaspartates (P-Asp) with different average molecular weights to study their proton transport properties. The number-average degree of polymerization (DP) for each P-Asp was 30 (P-Asp30), 115 (P-Asp115), 140 (P-Asp140), 160 (P-Asp160), 185 (P-Asp185), 205 (P-Asp205), and 250 (P-Asp250). The proton conductivity depended on the number-average DP. The maximum and minimum proton conductivities under a relative humidity of 70% and 298 K were 1.7 · 10?3 S cm?1 (P-Asp140) and 4.6 · 10?4 S cm?1 (P-Asp250), respectively. Differential thermogravimetric analysis (TG-DTA) was carried out for each P-Asp. The results were classified into two categories. One exhibited two endothermic peaks between t = (270 and 300) °C, the other exhibited only one peak. The P-Asp group with two endothermic peaks exhibited high proton conductivity. The high proton conductivity is related to the stability of the polymer. The number-average molecular weight also contributed to the stability of the polymer. 相似文献
110.
Ikeda S Kubota T Wang DO Yanagisawa H Yuki M Okamoto A 《Organic & biomolecular chemistry》2011,9(19):6598-6603
Fluorescent oligonucleotides have been designed on which two different energy transfer processes were mounted together: excitonic interaction and FRET. The fluorescence emission of the oligonucleotides was controlled well by the two different energy transfer processes, in response to their hybridization to the complementary RNA both in vitro and in cells. 相似文献