186 research outputs found
Effect of Cationic Micellar Reaction Field on Reaction Kinetics of Meisenheimer σ-Complex Formation between 1,3,5-Trinitrobenzene and Hydroxide Ion
Kinetic studies were done by using stopped-flow method for the Meisenheimer σ-complex formation reaction between 1,3,5-trinitrobenzene (TNB) and hydroxide ion in cationic micellar solutions of dodecyl-trimethylammonium bromide (DTAB), myristyltrimethylammonium bromide (MyTAB) and cetyltrimethylammonium bromide (CTAB) dissolved in aqueous solution, for the purpose of elucidating the influence of the microscopic heterogeneity of reaction field. The reaction rate analysis based on a pseudo-phase ion exchange model led us to a conclusion that the partition of reactant molecules between the micelle and water phase, and ion exchange between hydroxide ion and bromide ion existing as counter ions of cationic micellar surface were important. On the activation process, the enthalpy-entropy compensation relationships worked over the wide range of surfactant concentration. The derived isokinetic temperature, T_ revealed that in CTAB the reaction might be of enthalpy-control, and that in MyTAB be of entropy-control
Reaction Kinetics of Meisenheimer σ-Complex Formation between 2,4,6-Trinitrophenyl Chloride and Hydroxide Ion in Cationic Micellar Solution
Kinetic study was carried out by using stopped-flow method for the Meisenheimer σ-complex formation reaction between 2,4,6-trinitrophenyl chloride (picryl chloride: Pic-Cl) and hydroxide in aqueous cationic micellar solutions of dodecyltrimethylammonium bromide (DTAB), myristyltrimethylammonium bromide (MyTAB) and cetyltrimethyl-ammonium bromide (CTAB) dissolved in aqueous solution, for the purpose of elucidating the influence of the microscopic heterogeneity of reaction field on activation parameters. The reaction rate analysis based on a pseudo-phase ion exchange model led us to a conclusion that on the activation process the enthalpy-entropy compensation relationships worked over the wide range of surfactant concentration, and that, for the reaction occurring at the micellar surface, a reactant molecule effective to the reaction had to move into some restricted direction
Strain distribution analysis of sputter-formed strained Si by tip-enhanced Raman spectroscopy
Simultaneous nanometer-scale measurements of the strain and surface undulation distributions of strained Si (s-Si) layers on strain-relief quadruple-Si1-xGex-layer buffers, using a combined atomic force microscopy (AFM) and tip-enhanced Raman spectroscopy (TERS) system, clarify that an s-Si sample formed by our previously proposed sputter epitaxy method has a smoother and more uniformly strained surface than an s-Si sample formed by gas-source molecular beam epitaxy. The TERS analyses suggest that the compositional fluctuation of the underlying Si1-xGex buffer layer is largely related to the weak s-Si strain fluctuation of the sputtered sampl
Analysis of mTOR Inhibition-Involved Pathway in Ovarian Clear Cell Adenocarcinoma
This study was designed to clarify the mechanism of the mammalian target of rapamycin (mTOR)-hypoxia inducible factor-1 (HIF-1) pathway using the cultured cell strain derived from human ovarian clear cell adenocarcinoma (CCA). Everolimus (a derivative of rapamycin)-treated cells and non-treated cells did not show any difference in mTOR expression. But, phosphorylated-mTOR (p-mTOR) expression significantly decreased in the treated cells, and mTOR-related factors such as phosphorylated-4E-BP1 (p-4E-BP1), HIF-1α, and vascular endothelial growth factor (VEGF) in the downstream region of mTOR revealed a marked decrease in expression. The analysis of influences of the drug on the HIF-1α degradation system showed an increase in von-Hippel Lindau (VHL) expression in the treated cells. Increase of cleaved caspase-3, one of key factors involved in apoptosis, was also shown in the treated cells. In the next step, using nude mice implanted with RMG-1 cells, a decrease in tumor size was demonstrated in 4 of the 7 mice which were orally administered with everolimus. As a result, it was suggested that everolimus administration would be helpful as an anti-tumor therapy for CCA not only via down-regulation of p-mTOR but also degradation of HIF-1α by VHL and induction of apoptosis by cleaved caspase-3
CO Multi-line Imaging of Nearby Galaxies (COMING). IX. CO(=2-1)/CO(=1-0) line ratio on kiloparsec scales
While molecular gas mass is usually derived from CO(=1-0) - the
most fundamental line to explore molecular gas - it is often derived from
CO(=2-1) assuming a constant CO(=2-1)/CO(=1-0)
line ratio (). We present variations of and effects of the
assumption that is a constant in 24 nearby galaxies using CO
data obtained with the Nobeyama 45-m radio telescope and IRAM 30-m telescope.
The median of for all galaxies is 0.61, and the weighted mean of
by CO(=1-0) integrated-intensity is 0.66 with a standard
deviation of 0.19. The radial variation of shows that it is high
(~0.8) in the inner ~1 kpc while its median in disks is nearly constant at 0.60
when all galaxies are compiled. In the case that the constant of 0.7
is adopted, we found that the total molecular gas mass derived from
CO(=2-1) is underestimated/overestimated by ~20%, and at most by 35%.
The scatter of a molecular gas surface density within each galaxy becomes
larger by ~30%, and at most by 120%. Indices of the spatially resolved
Kennicutt-Schmidt relation by CO(=2-1) are underestimated by 10-20%,
at most 39% in 17 out of 24 galaxies. has good positive correlations
with star-formation rate and infrared color, and a negative correlation with
molecular gas depletion time. There is a clear tendency of increasing
with increasing kinetic temperature (). Further, we found that not
only but also pressure of molecular gas is important to
understand variations of . Special considerations should be made when
discussing molecular gas mass and molecular gas properties inferred from
CO(=2-1) instead of CO(=1-0).Comment: 29 pages, 18 figures, 5 tables. Accepted for publication in PASJ. The
original resolution version is available here
(https://astro3.sci.hokudai.ac.jp/~radio/coming/publications/COMING_IX_org_res.pdf
Prolapse of Intussusception through the Anus as a Result of Sigmoid Colon Cancer
Adult intussusception is rare and most often associated with cancer. We report a case of intussuscepted sigmoid colon into the rectum protruding from the anus of a 47-year-old woman. The cause of the intussusception was sigmoid colon cancer. We removed the intussuscepted part of the sigmoid colon as well as the rectum and regional lymph nodes. The patient recovered uneventfully and there has been no evidence of recurrence of the cancer
Scanning Differential-Phase-Contrast Hard X-Ray Microscopy with Wedge Absorber Detector
A new and simple idea for scanning differential-phase-contrast (S-DPC) hard X-ray microscopy has been proposed. It only uses a wedge absorber coupled with two intensity detectors, and is much more sensitive to sample structures than absorption contrast. It can also extract pure quantitative one-dimensional phase gradient given by a sample without an effect of sample absorption. The S-DPC microscope has been constructed at BL24XU of SPring-8, and its feasibility has been successfully demonstrated at the photon energy of 10 keV by clearly visualizing structures of samples. Further, the experimental phase gradient profile agrees well with simulation. By integrating the resultant phase gradient, the corresponding phase shift distribution could be also imaged. There are two main types in X-ray microscopes, one is an imaging type and the other is a scanning type. 1) The former provides direct magnification and shorter exposure time, while the latter provides digitally stored images with minimal radiation exposure to samples. 1) Recently, phasecontrast X-ray microscopy has rapidly grown in the hard Xray region since the advent of the 3 rd generation synchrotron radiation facilities. It is based on the fact that phase-shift cross section is almost a thousand times larger than absorption one for light elements as expected from a comparison between real and imaginary parts of the refractive index. 2,3) In the imaging type, the phase-contrast microscopy has been demonstrated by the Zernike's method 6) Further, we have recently demonstrated the novel imaging phase-contrast microscopy using a micro-interferometer consisting of a twin zone plate. 7) On the other hand, in the scanning type, the phase-contrast microscopy has been demonstrated by the configured 8) or segmented 9) detectors, the CCD-camera image-detections, 10-12) the diffracting aperture based method 13) and the dark-field imaging. 14,15) The former two require the highly sophisticated X-ray detector of electronic devises. The CCD-camera imagedetection must take diffraction images of a microbeam for all pixels, thus need a huge memory and the stored dataset must be processed later with an appropriate numerical calculation for image reconstruction. The diffracting aperture based method and the dark-field imaging are simple methods to realize the scanning phase-contrast microscopy, but phase information was not evaluated quantitatively. Here, we propose a new idea for S-DPC hard X-ray microscopy. It is a very simple way to purely extract quantitative one-dimensional phase gradient given by a sample to be imaged removing an effect of sample absorption by only adding a wedge absorber coupled with two intensity detectors into the normal scheme of the scanning microscopy. In this paper, the concept of the S-DPC hard X-ray microscopy is described and the feasibility test is presented. The principle of the S-DPC microscopy is illustrated i
Tolerability and Efficacy of Neoadjuvant Chemotherapy with a Tri-Weekly Interval Methotrexate, Doxorubicin, Vinblastine, and Cisplatin Regimen for Patients with Locally Advanced Bladder Cancer
Objective: Compared with standard treatment, a modified tri-weekly MVAC (methotrexate, doxorubicin, vinblastine, and cisplatin) treatment regimen with a high cisplatin dose intensity shows good efficacy and lower toxicity. Thus, we retrospectively investigated the tolerability and efficacy of a modified tri-weekly MVAC neoadjuvant regimen. Methods: We analyzed 25 patients with locally advanced bladder cancer medicated by a modified tri-weekly MVAC neoadjuvant regimen that omits treatment on days 15 and 22. The efficacy and tolerability were assessed retrospectively. Results: The numbers of patients in clinical stages 2, 3, and 4 were 13 (52.0%), 1 (4.0%), and 11 (44.0%), respectively. Surgery could be performed on all patients. Five patients (20.0%) had no cancer remaining in their surgical specimens. Remaining non-muscle-invasive cancer without metastasis was observed in 7 patients (28.0%), and the total downstaging rate was 44.0%. The 5-year overall and relapse-free survival rates were 79.0 and 75.0%, respectively. The overall relative dose intensity was 0.90. Serious hematologic toxicities rated grade 3 or greater were leukopenia in 6 patients (24.0%) and anemia in 1 patient (4.0%). Conclusions: Sufficient efficacy and tolerability of a modified tri-weekly MVAC neoadjuvant regimen were suggested. Thus, tri-weekly modified MVAC may be an option for neoadjuvant chemotherapy of advanced bladder cancer
TP53 codon 72 polymorphism is associated with FGFR3 and RAS mutation in non-muscle-invasive bladder cancer
ObjectiveTP53, a well-known tumor-suppressor gene in bladder carcinogenesis, has a functional single-nucleotide polymorphism on codon 72. The aim of this study was to elucidate the association between TP53 codon 72 polymorphism and somatic mutations in bladder cancer.Material and methodsGermline TP53 codon 72 polymorphism and somatic mutations of 50 cancer-associated genes were analyzed in 103 bladder cancer patients (59 non-muscle-invasive and 44 muscle-invasive), using Taqman genotyping assay and target sequencing, respectively. The expression of FGF-FGFR signaling pathway genes was analyzed by RNA sequencing of frozen tissue.ResultsThe allele frequency of TP53 codon 72 in our cohort was 37, 42, and 21% for Arg/Arg, Arg/Pro, and Pro/Pro, respectively. Interestingly, the prevalence of FGFR3 mutation was higher in patients with the Arg allele, whereas that of the RAS mutation was higher in patients without the Arg allele. The same association was seen in non-muscle-invasive bladder cancer (NMIBC) patients and no differences were observed in muscle-invasive bladder cancer patients. In NMIBC, FGFR1 expression was higher in patients without the Arg allele and FGFR3 expression was higher in patients with the Arg allele.ConclusionThe germline TP53 codon 72 polymorphism was associated with mutations of FGFR3 or RAS and expression of FGFR1 and FGFR3 in NMIBC. These findings provide new insight into the molecular mechanisms underlying the influence of the genetic background on carcinogenesis in bladder cancer
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