排序方式: 共有79条查询结果,搜索用时 15 毫秒
41.
Yasuhito Sugano Mun'delanji Vestergaard Hiroyuki Yoshikawa Masato Saito Eiichi Tamiya 《Electroanalysis》2010,22(15):1688-1694
Direct electricity generation from cellulose without saccharification and fermentation processes was achieved on gold electrode under the alkaline conditions. We (i) overcame problems with the insolubility of cellulose, and captured its electrochemical potential, and (ii) showed that cellulose was converted to cellulose derivatives due to electrochemical oxidation. In addition, we (iii) constructed a cellulose‐based fuel cell, demonstrating that cellulose can be direct electrical based fuel source. The presented fuel cell system overcomes the enormous distribution challenges encountered with other alternative bioenergy sources such as hydrogen. 相似文献
42.
Tsuyoshi Nakayama Ha Minh Hiep Satoshi Furui Yuji Yonezawa Masato Saito Yuzuru Takamura Eiichi Tamiya 《Analytical and bioanalytical chemistry》2010,396(1):457-464
DNA analysis with the polymerase chain reaction (PCR) has become a routine part of medical diagnostics, environmental inspections,
food evaluations, and biological studies. Furthermore, the development of a microscale PCR chip is an essential component
of studies aimed at integrating PCR into a micro total analysis system (μ-TAS). However, the occurrence of air bubbles in
microchannels complicates this process. In this study, we investigated a new technique based on the fluid dynamics of laminar
flow that utilizes a small amount of mineral oil at the beginning of sample injection to prevent air bubbles from occurring
in microchannels. We also further optimized the pressure, the length of the pressurizing channel and the volume of oil, thus
making our microfluidic device more useful for high-temperature PCR. Additionally, quantitative continuous-flow PCR was performed
using the optimized PCR chip in order to detect genetically modified (GM) maize. DNA was extracted from GM maize, MON 810,
and non-GM maize at several concentrations from 0% (w/v) to 100% (w/v). The DNA amplification signals were then analyzed on
the PCR chip using a laser-based system. The signal from our microfluidic PCR chip was found to increase in direct proportion
to the initial GM maize concentration. 相似文献
43.
Tanaka R Yuhi T Nagatani N Endo T Kerman K Takamura Y Tamiya E 《Analytical and bioanalytical chemistry》2006,385(8):1414-1420
The immunochromatographic assay is a well-known and convenient diagnostic system. In this report, the development of a novel
enhancement assay for the test strips is described. Additionally, this highly sensitive immunochromatographic assay was applied
to detect human chorionic gonadotropin hormone (HCG) as the model case. The primary antibody-conjugated gold nanoparticles
were used as the enhancer of the standard method. The primary antibodies were immobilized within a defined detection zone
(test line) on the diagnostic nitrocellulose membrane. The secondary antibodies were conjugated with colloidal gold nanoparticles.
In combination with an effective sample pretreatment, the gold-conjugated antibodies and the primary antibodies formed a sandwich
complex with the target protein. Within the test line, the sandwich complex was immobilized, and furthermore, concentrated
by the enhancer resulting in a localized surface plasmon resonance (LSPR) phenomenon and a distinct red color on the test
line. The intensity of color of the red test line (signal intensity), which correlated directly with the concentration of
the target protein in the standard or spiked samples, was assessed visually and by computer image analysis using a three-determination
analysis. Under optimum conditions, the limit of detection (LOD) for HCG assay was 1 pg/mL. When using human serum, 10 pg/mL
of HCG could be detected. We have also spiked total prostate-specific antigen (TPSA) in female serum. The LOD for TPSA was
determined as 0.2 ng/mL. With this method, the quantitative determination of the target protein could be completed in less
than 15 min. Our novel immunochromatographic strips using the enhancing method based on LSPR of gold nanoparticles are useful
as a rapid and simple screening method for the detection of important analytes for medical applications, environmental monitoring,
food control, and biosecurity.
相似文献
44.
45.
Kaminikado K Ikeda R Idegami K Nagatani N Vestergaard MC Saito M Tamiya E 《The Analyst》2011,136(9):1826-1830
We present a rapid gel electrophoretic chip, composed of 2.5% (w/v) acrylamide and 1% (w/v) agarose gel, for serum cholesterol determination using a photo lithography technique. After optimizations, we determined the lipoprotein concentration of standard serum using a conventional enzyme method. The serum was diluted, stained and loaded for 15 min onto the chip. After loading, the intensities of low density lipoprotein cholesterol (LDL-C) and high density lipoprotein cholesterol (HDL-C) bands separated at the chip were estimated using an image analyzer. The intensities of these bands corresponded to concentrations obtained from a standard enzyme-based method. The detected LDL-C and HDL-C concentrations were linear up to 146 mg dL(-1) and 53 mg dL(-1) respectively. Finally, we carried out the cholesterol analysis using real biological samples obtained from nine volunteers using our electrophoretic chip. The LDL-C and HDL-C levels detected using our chip correlated well with the results obtained using the conventional enzyme-based method r(2) = 0.98 and r(2) = 0.86 for LDL-C and HDL-C, respectively. Although our sample size is small and confined only to health volunteers, we have demonstrated that this proof-of-concept gel electrophoretic chip can determine lipoproteins, simultaneously. 相似文献
46.
Ha Minh Hiep Masato Saito Yoshikazu Nakamura Eiichi Tamiya 《Analytical and bioanalytical chemistry》2010,396(7):2575-2581
Developments of optical protein sensors with nanostructure based on the noble metals have currently received great attention
for their high efficiency and simultaneous analysis of various important biomolecules from proteomics to genetics. In this
study, we exploited the absorbance spectra of gold-capped nanoparticles substrate for label-free detections of antigen–antibody
reactions using a specific thiolated RNA aptamer. These synthesized RNA aptamers have been optimized to bind to the Fc portion
of the human IgG1 subclass, due to their ability to orient antibodies direction on the gold surface. After attaching the anti-fibrinogen
antibodies on the surface via these linkers, our thiolated RNA aptamer-based nanostructured sensors were easily applicable
to specific detections of fibrinogen with a limit of detection of 0.1 ng/mL. These nanostructured sensor-based models will
open a way to display numerous immunosensors as well as to develop other functionally similar sensors which could then be
expanded into multi-arrays assay systems. 相似文献
47.
Dr. Yoko Sakata Masahiro Okada Munehiro Tamiya Prof. Shigehisa Akine 《Chemistry (Weinheim an der Bergstrasse, Germany)》2020,26(34):7595-7601
We propose post-metalation modification as a useful strategy to control the guest recognition behavior of a metal-containing macrocyclic host. This is based on the ligand exchange of the axial ligands of a cobalt(III) dinuclear macrocyclic host, [LCo2X4]2+ (X=axial amine ligand). Four piperidine ligands in [LCo2(pip)4]2+ (pip=piperidine) were site-selectively replaced with primary amines. The competitive experiments revealed that the order of the affinity toward the cobalt centers in [LCo2X4]2+ is primary amine > secondary amine > tertiary amine and that the piperidine-coordinating complex, [LCo2(pip)4]2+, was reasonably reactive among the isolable complexes. Indeed, two piperidine ligands at the diagonal positions in [LCo2(pip)4]2+ were site-selectively replaced with pyridine or acetate ion. The replacement of piperidine with acetate ion significantly enhanced the recognition ability towards Na+. 相似文献
48.
Alzheimer's disease (AD) is marked by the accumulation of neuronal plaques from insoluble amyloid-beta (Aβ) peptides. Growing evidence for the role of Aβ oligomers in neuronal cell cytotoxicity and pathogenesis has prompted the development of novel techniques to better understand the early stages of aggregation. Near infrared (NIR) optical trapping was applied to characterize the early stages of Aβ aggregation in the presence of a β-sheet intercalating dye, Congo Red (CR), as the fluorescent marker. The integration of fluorescence analysis with NIR optical trapping has provided a new outlook into the first two hours of Aβ aggregation. 相似文献
49.
Hoshina K Kawamura H Tsuge M Tamiya M Ishiguro M 《The Journal of chemical physics》2011,134(6):064324
We investigated a formation channel of triatomic molecular hydrogen ions from ethane dication induced by irradiation of intense laser fields (800 nm, 100 fs, ~1 × 10(14) W∕cm(2)) by using time of flight mass spectrometry. Hydrogen ion and molecular hydrogen ion (H,D)(n)(+) (n = 1-3) ejected from ethane dications, produced by double ionization of three types of samples, CH(3)CH(3), CD(3)CD(3), and CH(3)CD(3), were measured. All fragments were found to comprise components with a kinetic energy of ~3.5 eV originating from a two-body Coulomb explosion of ethane dications. Based on the signal intensities and the anisotropy of the ejection direction with respect to the laser polarization direction, the branching ratios, H(+):D(+) = 66:34, H(2)(+):HD(+):D(2)(+) = 63:6:31, and H(3)(+):H(2)D(+):HD(2)(+):D(3)(+) = 26:31:34:9 for the decomposition of C(2)H(3)D(3)(2+), were determined. The ratio of hydrogen molecules, H(2):HD:D(2) = 31:48:21, was also estimated from the signal intensities of the counter ion C(2)(H,D)(4)(2+). The similarity in the extent of H∕D mixture in (H,D)(3)(+) with that of (H,D)(2) suggests that these two dissociation channels have a common precursor with the C(2)H(4)(2+)...H(2) complex structure, as proposed theoretically in the case of H(3)(+) ejection from allene dication [A. M. Mebel and A. D. Bandrauk, J. Chem. Phys. 129, 224311 (2008)]. In contrast, the (H,D)(2)(+) ejection path with a lower extent of H∕D mixture and a large anisotropy is expected to proceed essentially via a different path with a much rapid decomposition rate. For the Coulomb explosion path of C-C bond breaking, the yield ratios of two channels, CH(3)CD(3)(2+)→ CH(3)(+) + CD(3)(+) and CH(2)D(+) + CHD(2)(+), were 81:19 and 92:8 for the perpendicular and parallel directions, respectively. This indicates that the process occurs at a rapid rate, which is comparable to hydrogen migration through the C-C bond, resulting in smaller anisotropy for the latter channel that needs H∕D exchange. 相似文献
50.
We have developed a rapid immunoglobulin G (IgG) and a human serum albumin (HSA) depletion protocol. We depleted both HSA and IgG (> 97%) separately, and in a single procedure. The method is specific and reproducible (RSD < 1.0%), and substantially lowered the detection limit of prostate-specific antigen, a prostate cancer biomarker. The method can be applied to other biomarkers and proteomic studies. Interestingly, the depletion of HSA might not be blankly as beneficial as widely portrayed. Our study suggests the depletion of IgG to be more beneficial than albumin depletion. 相似文献