365 research outputs found
Broadband coherent Raman scattering spectroscopy at 50,000,000 spectra/s
Raman scattering spectroscopy is widely used as an analytical technique in
various fields, but its measurement process tends to be slow due to the low
scattering cross-section. In the last decade, various broadband coherent Raman
scattering spectroscopy techniques have been developed to address this
limitation, achieving a measurement rate of about 100 kSpectra/s. Here, we
present a significantly increased measurement rate of 50 MSpectra/s, which is
500 times higher than the previous state-of-the-art, by developing time-stretch
coherent Raman scattering spectroscopy. Our newly-developed system, based on a
mode-locked Yb fiber laser, enables highly-efficient broadband excitation of
molecular vibrations via impulsive stimulated Raman scattering with an
ultrashort femtosecond pulse and sensitive time-stretch detection with a
picosecond probe pulse at a high repetition rate of the laser. As a
proof-of-concept demonstration, we measure broadband coherent Stokes Raman
scattering spectra of organic compounds covering the molecular fingerprint
region from 200 to 1,200 cm-1. This high-speed broadband vibrational
spectroscopy technique holds promise for unprecedented measurements of
sub-microsecond dynamics of irreversible phenomena and extremely
high-throughput measurements
The relationship between histochemical enzyme activities of brain tumors and clinical features of the patients
Human brain turnors removed from 126 patients were histochemically examined and following results were obtained. 1. In general, alkaline phosphatase activity is decreased in poorly differentiated gliomas, but is not related to the tumor cell infiltration. 2. All the cases of alkaline phosphatase negative gliomas have poor reconvalescent course and most of the positive cases show good reconvalescence. 3. Alkaline phosphatase, leucine aminopeptidase and acid phosphatase activities are remarkable in fibroblastic meningioma, moderate or feeble in meningocytic meningioma, and negative in malignant meningioma. 4. The activities of alkaline phosphatase, β-esterase, leucine aminopeptidase and acid phosphatase are decreased in most of meningocytic meningiomas when the duration of symptoms and signs is short. 5. Succinic dehydrogenase, malic dehydrogenase, isocitric dehydrogenase and β-glucuronidase are strongly reactive in malignant meningioma; from strong to moderate in meningocytic meningioma and from moderate to feeble in fibroblastic meningioma. 6. There is a slight increasing tendency of the activities of succinic dehydrogenase, malic dehydrogenase, isocitric dehydrogenase in fibroblastic meningioma and p¡glucuronidase for a short duration of symtoms and signs.
7. In the case of acoustic neurinomas the higher the alkaline phosphatase activity, the longer is the duration of symptoms and signs.</p
Mid-infrared optical coherence tomography with MHz axial line rate for real-time non-destructive testing
Non-destructive testing (NDT) is crucial for ensuring product quality and
safety across various industries. Conventional methods such as ultrasonic,
terahertz, and X-ray imaging have limitations in terms of probe-contact
requirement, depth resolution, or radiation risks. Optical coherence tomography
(OCT) is a promising alternative to solve these limitations, but it suffers
from strong scattering, limiting its penetration depth. Recently, OCT in the
mid-infrared (MIR) spectral region has attracted attention with a significantly
lower scattering rate than in the near-infrared region. However, the highest
reported A-scan rate of MIR-OCT has been 3 kHz, which requires long data
acquisition time to take an image, unsatisfying industrial demands for
real-time diagnosis. Here, we present a high-speed MIR-OCT system operating in
the 3-4 um region that employs the swept-source OCT technique based on
time-stretch infrared spectroscopy. By integrating a broadband femtosecond MIR
pulsed laser operating at a repetition rate of 50 MHz, we achieved an A-scan
rate of 1 MHz with an axial resolution of 11.6 um and a sensitivity of 55 dB.
As a proof-of-concept demonstration, we imaged the surface of substrates
covered by highly scattering paint coatings. The demonstrated A-scan rate
surpasses previous state-of-the-art by more than two orders of magnitude,
paving the way for real-time NDT of industrial products, cultural assets, and
structures
Broadband dielectric spectroscopy of glucose aqueous solution: Analysis of the hydration state and the hydrogen bond network.
Recent studies of saccharides' peculiar anti-freezing and anti-dehydration properties point to a close association with their strong hydration capability and destructuring effect on the hydrogen bond (HB) network of bulk water. The underlying mechanisms are, however, not well understood. In this respect, examination of the complex dielectric constants of saccharide aqueous solutions, especially over a broadband frequency region, should provide interesting insights into these properties, since the dielectric responses reflect corresponding dynamics over the time scales measured. In order to do this, the complex dielectric constants of glucose solutions between 0.5 GHz and 12 THz (from the microwave to the far-infrared region) were measured. We then performed analysis procedures on this broadband spectrum by decomposing it into four Debye and two Lorentz functions, with particular attention being paid to the β relaxation (glucose tumbling), δ relaxation (rotational polarization of the hydrated water), slow relaxation (reorientation of the HB network water), fast relaxation (rotation of the non-HB water), and intermolecular stretching vibration (hindered translation of water). On the basis of this analysis, we revealed that the hydrated water surrounding the glucose molecules exhibits a mono-modal relaxational dispersion with 2-3 times slower relaxation times than unperturbed bulk water and with a hydration number of around 20. Furthermore, other species of water with distorted tetrahedral HB water structures, as well as increases in the relative proportion of non-HB water molecules which have a faster relaxation time and are not a part of the surrounding bulk water HB network, was found in the vicinity of the glucose molecules. These clearly point to the HB destructuring effect of saccharide solutes in aqueous solution. The results, as a whole, provide a detailed picture of glucose-water and water-water interactions in the vicinity of the glucose molecules at various time scales from sub-picosecond to hundreds of picoseconds
Somatic chromosomal translocation between Ewsr1 and Fli1 loci leads to dilated cardiomyopathy in a mouse model
A mouse model that recapitulates the human Ewing's sarcoma-specific chromosomal translocation was generated utilizing the Cre/loxP-mediated recombination technique. A cross between Ewsr1-loxP and Fli1-loxP mice and expression of ubiquitous Cre recombinase induced a specific translocation between Ewsr1 and Fli1 loci in systemic organs of both adult mice and embryos. As a result Ewsr1-Fli1 fusion transcripts were expressed, suggesting a functional Ews-Fli1 protein might be synthesized in vivo. However, by two years of age, none of the Ewsr1-loxP/Fli1-loxP/CAG-Cre (EFCC) mice developed any malignancies, including Ewing-like small round cell sarcoma. Unexpectedly, all the EFCC mice suffered from dilated cardiomyopathy and died of chronic cardiac failure. Genetic recombination between Ewsr1 and Fli1 was confirmed in the myocardial tissue and apoptotic cell death of cardiac myocytes was observed at significantly higher frequency in EFCC mice. Moreover, expression of Ews-Fli1 in the cultured cardiac myocytes induced apoptosis. Collectively, these results indicated that ectopic expression of the Ews-Fli1 oncogene stimulated apoptotic signals, and suggested an important relationship between oncogenic signals and cellular context in the cell-of-origin of Ewing's sarcoma
Molecular phylogeny and evolution of alcohol dehydrogenase (Adh) genes in legumes
BACKGROUND: Nuclear genes determine the vast range of phenotypes that are responsible for the adaptive abilities of organisms in nature. Nevertheless, the evolutionary processes that generate the structures and functions of nuclear genes are only now be coming understood. The aim of our study is to isolate the alcohol dehydrogenase (Adh) genes in two distantly related legumes, and use these sequences to examine the molecular evolutionary history of this nuclear gene. RESULTS: We isolated the expressed Adh genes from two species of legumes, Sophora flavescens Ait. and Wisteria floribunda DC., by a RT-PCR based approach and found a new Adh locus in addition to homologues of the Adh genes found previously in legumes. To examine the evolution of these genes, we compared the species and gene trees and found gene duplication of the Adh loci in the legumes occurred as an ancient event. CONCLUSION: This is the first report revealing that some legume species have at least two Adh gene loci belonging to separate clades. Phylogenetic analyses suggest that these genes resulted from relatively ancient duplication events
Chimeric Anti-PDPN Antibody ChLpMab-2
Human podoplanin (hPDPN ), a platelet aggregationâinducing transmembrane glycoprotein, is expressed in different types of tumors, and it binds to Câtype lectinâlike receptor 2 (CLEC â2). The overexpression of hPDPN is involved in invasion and metastasis. AntiâhPDPN monoclonal antibodies (mAbs) such as NZ â1 have shown antitumor and antimetastatic activities by binding to the platelet aggregationâstimulating (PLAG ) domain of hPDPN . Recently, we developed a novel mouse antiâhPDPN mAb, LpMabâ2, using the cancerâspecific mAb (CasMab) technology. In this study we developed chLpMabâ2, a humanâmouse chimeric antiâhPDPN antibody, derived from LpMabâ2. chLpMabâ2 was produced using fucosyltransferase 8âknockout (KO ) Chinese hamster ovary (CHO )âS cell lines. By flow cytometry, chLpMabâ2 reacted with hPDPN âexpressing cancer cell lines including glioblastomas, mesotheliomas, and lung cancers. However, it showed low reaction with normal cell lines such as lymphatic endothelial and renal epithelial cells. Moreover, chLpMabâ2 exhibited high antibodyâdependent cellular cytotoxicity (ADCC ) against PDPN âexpressing cells, despite its low complementâdependent cytotoxicity. Furthermore, treatment with chLpMabâ2 abolished tumor growth in xenograft models of CHO /hPDPN , indicating that chLpMabâ2 suppressed tumor development via ADCC . In conclusion, chLpMabâ2 could be useful as a novel antibodyâbased therapy against hPDPN âexpressing tumors
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