290 research outputs found
Absolute elastic differential cross sections for electron scattering by C6H5CH3 and C6H5CF3 at 1.5–200 eV: a comparative experimental and theoretical study with C6H6
We present absolute differential cross sections DCS for elastic scattering from two benzene derivatives
C6H5CH3 and C6H5CF3. The crossed-beam method was used in conjunction with the relative flow technique
using helium as the reference gas to obtain absolute values. Measurements were carried out for scattering
angles 15° –130° and impact energies 1.5–200 eV. DCS results for these two molecules were compared to
those of C6H6 from our previous study. We found that 1 these three molecules have DCS with very similar
magnitudes and shapes over the energy range 1.5–200 eV, although DCS for C6H5CF3 increase steeply toward
lower scattering angles due to the dipole moment induced long-range interaction at 1.5 and 4.5 eV, and 2 that
the molecular structure of the benzene ring significantly determines the collision dynamics. From the measured
DCS, elastic integral cross sections have been calculated. Furthermore, by employing a corrected form of the
independent-atom method known as the screen corrected additive rule, DCS calculations have been carried out
without any empirical parameter fittings, i.e., in an ab initio nature. Results show that the calculated DCS are
in excellent agreement with the experimental values at 50, 100, and 200 eV
Effect of αB-Crystallin on Protein Aggregation in Drosophila
Disorganisation and aggregation of proteins containing expanded polyglutamine (polyQ) repeats, or ectopic expression of α-synuclein, underlie neurodegenerative diseases including Alzheimer's, Parkinson, Huntington, Creutzfeldt diseases. Small heat-shock proteins, such as αB-crystallin, act as chaperones to prevent protein aggregation and play a key role in the prevention of such protein disorganisation diseases. In this study, we have explored the potential for chaperone activity of αB-crystallin to suppress the formation of protein aggregates. We tested the ability of αB-crystallin to suppress the aggregation of a polyQ protein and α-synuclein in Drosophila. We found that αB-crystallin suppresses both the compound eye degeneration induced by polyQ and the α-synuclein-induced rough eye phenotype. Furthermore, by using histochemical staining we have determined that αB-crystallin inhibits the aggregation of polyQ in vivo. These data provide a clue for the development of therapeutics for neurodegenerative diseases
Antioxidant Activity and Oxidation Products of 1,2,3,4- Tetrahydroquinoxalines in Peroxyl Radical Scavenging Reactions, Part I
This paper studies the antioxidant activity of 1,2,3,4-tetrahydroquinolines, 3,4-dihydro-2H-benzo[1,4]thiazines and 1,2,3,4-tetrahydroquinoxalines in the inhibition of the peroxidation of tetralin induced by an azo initiator. Neither 1,2,3,4- tetrahydroquinoline nor 3,4-dihydro-2H-benzo[1,4]thiazine alone acted as an antioxidant, but when they have an electron-donating group at the para position to the NH group, they act as potent antioxidants. On the other hand, 1,2,3,4- tetrahydroquinoxaline on its own showed good antioxidant activity. However, 1,2,3,4-tetrahydroquinoxalines with methyl and methoxy groups in the phenyl ring have reactivities similar to or less than that of unsubstituted 1,2,3,4-tetrahydroquinoxaline. The induction periods of 1,2,3,4-tetrahydroquinoxalines with an alkyl group or phenyl group at the 2-position were all longer than the value for the unsubstituted 1,2,3,4-tetrahydroquinoxaline, except for a compound with a t-butyl group. The oxidation of 1,2,3,4-tetrahydroquinoxalines by peroxyl radicals generated from an azo initiator in tetralin or benzene yields quinoxalines and a dimer product of quinoxalines, 6-(1,2,3,4-tetrahydroquinoxalin-1-yl)-quinoxaline
Identification of anti-cancer chemical compounds using Xenopus embryos
Cancer tissues have biological characteristics similar to those observed in embryos during development. Many types of cancer cells acquire pro-invasive ability through epithelial-mesenchymal transition (EMT). Similar processes (gastrulation and migration of cranial neural crest cells [CNCC]) are observed in the early stages of embryonic development in Xenopus during which cells that originate from epithelial sheets through EMT migrate to their final destinations. The present study examined Xenopus embryonic tissues to identify anti-cancer compounds that prevent cancer invasion. From the initial test of known anti-cancer drugs, AMD3100 (an inhibitor of CXCR4) and paclitaxel (a cytoskeletal drug targeting microtubules) effectively prevented migration during gastrulation or CNCC development. Blind-screening of 100 synthesized chemical compounds was performed, and nine candidates that inhibited migration of these embryonic tissues without embryonic lethality were selected. Of these, C-157 (an analog of podophyllotoxin) and D-572 (which is an indole alkaroid) prevented cancer cell invasion through disruption of interphase microtubules. In addition, these compounds affected progression of mitotic phase and induced apoptosis of SAS oral cancer cells. SAS tumors were reduced in size after intratumoral injection of C-157, and peritoneal dissemination of melanoma cells and intracranial invasion of glioma cells were inhibited by C-157 and D-572. When the other analogues of these chemicals were compared, those with subtle effect on embryos were not tumor suppressive. These results suggest that a novel chemical-screening approach based on Xenopus embryos is an effective method for isolating anti-cancer drugs and, in particular, targeting cancer cell invasion and proliferation
Functional tooth restoration by next-generation bio-hybrid implant as a bio-hybrid artificial organ replacement therapy
Bio-hybrid artificial organs are an attractive concept to restore organ function through precise biological cooperation with surrounding tissues in vivo. However, in bio-hybrid artificial organs, an artificial organ with fibrous connective tissues, including muscles, tendons and ligaments, has not been developed. Here, we have enveloped with embryonic dental follicle tissue around a HA-coated dental implant, and transplanted into the lower first molar region of a murine tooth-loss model. We successfully developed a novel fibrous connected tooth implant using a HA-coated dental implant and dental follicle stem cells as a bio-hybrid organ. This bio-hybrid implant restored physiological functions, including bone remodelling, regeneration of severe bone-defect and responsiveness to noxious stimuli, through regeneration with periodontal tissues, such as periodontal ligament and cementum. Thus, this study represents the potential for a next-generation bio-hybrid implant for tooth loss as a future bio-hybrid artificial organ replacement therapy
Preventative Effect of a Flavonoid, Enzymatically Modified Isoquercitrin on Ocular Symptoms of Japanese Cedar Pollinosis
ABSTRACTBackgroundFlavonoids are nutrients that exert anti-allergic effects. We investigated the preventative effect of enzymatically modified isoquercitrin (EMIQ), a flavonoid, to relieve the symptoms of Japanese cedar pollinosis.MethodsIn a parallel-group, double-blind placebo-controlled study design, 24 subjects with Japanese cedar pollinosis took 100 mg EMIQ or a placebo for 8 weeks, starting 4 weeks prior to the onset of pollen release. Subjective symptoms, ADL scores and the usage of drugs were recorded daily, and the QOL score was obtained every 4 weeks. Blood sampling was performed before and after the study to measure serum levels of IgE and flavonoids.ResultsDuring the entire study period, ocular symptom + medication score for the EMIQ group was significantly lower (p < 0.05) than that of the placebo group. When limited to the period, ocular symptom scores (p < 0.05, weeks 5–6), and ocular congestion scores (p < 0.05, weeks 5–6) for the EMIQ group was significantly lower than that for the placebo group while other scores for the EMIQ group, such as ocular itching scores (p = 0.09, weeks 4–5), lacrimation scores (p = 0.07, weeks 5–6), and ocular congestion scores (p = 0.06, weeks 45), all tended to be lower. However no significant differences were found in nasal symptoms between the two groups. Serum concentrations of IgE were not significantly downregulated but the serum concentrations of quercetin and its derivatives were elevated significantly by the intake of EMIQ.ConclusionsIntake of the quercetin glycoside EMIQ proved to be effective for the relief of ocular symptoms caused by Japanese cedar pollinosis
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