863 research outputs found
Quantum oscillations of nitrogen atoms in uranium nitride
The vibrational excitations of crystalline solids corresponding to acoustic
or optic one phonon modes appear as sharp features in measurements such as
neutron spectroscopy. In contrast, many-phonon excitations generally produce a
complicated, weak, and featureless response. Here we present time-of-flight
neutron scattering measurements for the binary solid uranium nitride (UN),
showing well-defined, equally-spaced, high energy vibrational modes in addition
to the usual phonons. The spectrum is that of a single atom, isotropic quantum
harmonic oscillator and characterizes independent motions of light nitrogen
atoms, each found in an octahedral cage of heavy uranium atoms. This is an
unexpected and beautiful experimental realization of one of the fundamental,
exactly-solvable problems in quantum mechanics. There are also practical
implications, as the oscillator modes must be accounted for in the design of
generation IV nuclear reactors that plan to use UN as a fuel.Comment: 25 pages, 10 figures, submitted to Nature Communications,
supplementary information adde
Shubnikov-de Haas quantum oscillations reveal a reconstructed Fermi surface near optimal doping in a thin film of the cuprate superconductor Pr1.86Ce0.14CuO4±δ
We study magnetotransport properties of the electron-doped superconductor Pr2-xCexCuO4±δ with x=0.14 in magnetic fields up to 92 T, and observe Shubnikov-de Haas magnetic quantum oscillations. The oscillations display a single frequency F=255±10 T, indicating a small Fermi pocket that is ∼1% of the two-dimensional Brillouin zone and consistent with a Fermi surface reconstructed from the large holelike cylinder predicted for these layered materials. Despite the low nominal doping, all electronic properties including the effective mass and Hall effect are consistent with overdoped compounds. Our study demonstrates that the exceptional chemical control afforded by high quality thin films will enable Fermi surface studies deep into the overdoped cuprate phase diagram
Hobby engagement and risk of disabling dementia
BACKGROUND: The association between hobby engagement and risk of dementia reported from a short-term follow-up study for individuals aged ≥65 years may be liable to reverse causation. We examined the association between hobby engagement in age of 40-69 years and risk of dementia in a long-term follow-up study among Japanese including individuals in mid-life, when the majority of individuals have normal cognitive function. METHODS: A total of 22,377 individuals aged 40-69 years completed a self-administered questionnaire in 1993-1994. The participants answered whether they had hobbies according to the three following responses: having no hobbies, having a hobby, and having many hobbies. Follow-up for incident disabling dementia was conducted with long-term care insurance data from 2006 to 2016. RESULTS: During 11.0 years of median follow-up, 3,095 participants developed disabling dementia. Adjusting for the demographic, behavioral, and psychosocial factors, the multivariable hazard ratios (95% confidence intervals) of incident disabling dementia compared with "having no hobbies" were 0.82 (0.75-0.89) for "having a hobby" and 0.78 (0.67-0.91) for "having many hobbies". The inverse association was similarly observed in both middle (40-64 years) and older ages (65-69 years). For disabling dementia subtypes, hobby engagement was inversely associated with the risk of dementia without a history of stroke (probably non-vascular type dementia), but not with that of post-stroke dementia (probably vascular type dementia). CONCLUSIONS: Hobby engagement in both mid-life and late-life was associated with a lower risk of disabling dementia without a history of stroke
PEMANFAATAN MODEL KELAS SEBAGAI SUMBER BELAJAR DALAM PEMBELAJARAN IPS UNTUK MENGEMBANGKAN KARAKTER DAN KECERDASAN EMOSIONAL SISWA KELAS IV SEKOLAH DASAR NEGERI 74 KOTA BENGKULU
Penelitian ini bertujuan untuk : (1) Mengembangkan model kelas sebagai sumber belajar dalam pembelajaran IPS, (2) Mengembangkan karakter siswa melalui pemanfaatan model kelas sebagai sumber belajar dalam pembelajaran IPS, (3) Mengembangkan kecerdasan emosional siswa melalui pemanfaatan model kelas sebagai sumber belajar dalam pembelajaran IPS, dan (4) Meningkatkan hasil belajar kognitif siswa melalui pemanfaatan model kelas sebagai sumber belajar dalam pembelajaran IPS. Metode yang digunakan yaitu Penelitian Tindakan Kelas (PTK). Penelitian ini dilaksanakan secara kolaboratif antara 2 orang dosen PGSD, 2 orang guru SD, da 5 orang mahasiswa PGSD. Hasil penelitian menunjukkan bahwa : (1) Pengembangan model kelas sebagai sumber belajar dalam pembelajaran IPS dilakukan melalui empat tahap yaitu : orientasi, elaborasi dan interpretasi, aplikasi ide dan evaluasi, (2) Pemanfaatan model kelas sebagai sumber belajar dalam pembelajaran IPS dapat mengembangkan karakter siswa, (3) Pemanfaatan model kelas sebagai sumber belajar dalam pembelajaran IPS dapat mengembangkan kecerdasan emosional siswa, dan (4) Pemanfaatan model kelas sebagai sumber belajar dalam pembelajaran IPS dapat meningkatkan hasil belajar kognitif siswa. Saran yang disampaikan yakni : (1) Guru dan calon guru diharapkan memanfaatkan model kelas dalam pembelajaran IPS, dan (2) Kepala sekolah diharapkan mendorong guru untuk selalu menerapkan pembelajaran dengan memanfaatkan model kelas
A case study on the rainfall distribution over the Japan Islands associated with the approach of Ty0423 in late October (Comparison with that for Ty0418)
Rainfall distribution in the Japan Islands associated with the approach of Typhoon No.23 around 20 October
2004 (referred to Ty0423, hereafter) showed considerably different features from those in late summer of this
year. The present study examined the detailed rainfall features around the Japan Islands brought by Ty0423
and the atmospheric processes based on the operational observation data by the Japan Meteorological Agency
(JMA), comparing with those in association with Ty0418 around 7 September 2004.
During the stage when Ty0423 was approaching or landing on the western part of the Japan Islands, the
areal mean precipitation from Kyushu to Kanto District attained much larger than that for Ty0418, with wider
extension of the area with the large amount of precipitation. It is interesting that, although the intense rainfall
was observed only at the upstream side of the mountain range from Kyushu to Honshu District for Ty0418
except for the area near its center, strong rainfall with 10~30 mm/h persisted in wider regions from the western
to the eastern part of the Japan Islands, resulting in the considerably large total rainfall for Ty0423.
As for the case for Ty0423, the surface front with stable frontal surface was located just to the east of the
Ty0423 center just before its landing at the Japan Islands. Thus, the huge moisture inflow mainly in the eastern
region from the typhoon center seems to be redistributed widely over the Japan Islands area associated with
the large-scale convergence around the stable frontal surface. In late October, the colder air associated with
the high pressure system in the eastern Siberia can cover the northern part of the Japan Sea area as the seasonal
march. Such basic field might be favorable for sustaining the synoptic-scale front just around the southern
coast of the Japan Islands, even when the strong southerly wind invades associated with the typhoon approach
there
Dual functions of discoidinolysin, a cholesterol-dependent cytolysin with N-terminal discoidin domain produced from Streptococcus mitis strain Nm-76
Background: Some strains of Streptococcus mitis exhibit β-hemolysis due to the β-hemolytic activity of cholesterol-dependent cytolysin (CDC). Recently, a gene encoding an atypical lectinolysin-related CDC was found in S. mitis strain Nm-76. However, the product of this gene remains uncharacterized. We aimed to characterize this atypical CDC and its molecular functions and contribution to the pathogenicity of S. mitis strain Nm-76.
Methods: Phylogenetic analysis of the CDC gene was conducted based on the web-deposited information. The molecular characteristics of CDC were investigated using a gene-deletion mutant strain and recombinant proteins expressed in Escherichia coli.
Results: The gene encoding CDC found in Nm-76 and its homolog are distributed among many S. mitis strains. This CDC is phylogenetically different from other previously characterized CDCs, such as S. mitis-derived human platelet aggregation factor (Sm-hPAF)/lectinolysin and mitilysin. Because this CDC possesses an additional N-terminal domain, including a discoidin motif, it was termed discoidinolysin (DLY). In addition to the preferential lysis of human cells, DLY displayed N-terminal domain-dependent facilitation of human erythrocyte aggregation and intercellular associations between human cells.
Conclusion: DLY functions as a hemolysin/cytolysin and erythrocyte aggregation/intercellular association molecule. This dual-function DLY could be an additional virulence factor in S. mitis
Effect of High Fat Loading in Dahl Salt-Sensitive Rats
Salt sensitivity of blood pressure (BP) is speculated to be a characteristic in obesity-induced hypertension. To elucidate the influence of obesity on salt-sensitive hypertension, we examined the effect of fat loading on BP, renal damage, and their progression induced by salt excess in Dahl salt-sensitive (S) rats. High fat (HF: 45% fat diet: 8 weeks) diet increased BP with greater weight gain and visceral fat accumulation than low fat (10% fat) diet. In HF-fed rats, plasma glucose, plasma insulin, and urinary catecholamine increased, and urinary protein tended to be elevated. Moreover, excessive salt (8% salt diet: 8 weeks)-induced hypertension and proteinuria was accelerated in HF-fed rats. Therefore, fat loading increased BP in Dahl S rats possibly through insulin-resistance and sympathetic excitation. Moreover, fat loading accelerated salt-induced BP elevation and renal damage, suggesting excessive intake of both fat and salt, such as a civilized diet, exert the synergic harmful effects
Potential tactics with certain gut microbiota for the treatment of unresectable hepatocellular carcinoma
Hepatocellular carcinoma (HCC) constitutes an extremely malignant form of primary liver cancer. Intricate connections linking to the immune system might be associated with the pathogenesis of HCC. Meanwhile, immunotherapy with immune checkpoint inhibitors has been established to be a favorable therapeutic possibility for advanced HCC. Although curative opportunities for advanced HCC are restricted, the immune checkpoint immunotherapy has developed as the main choice for treating HCC. However, patients with metabolic-associated fatty liver disease (MAFLD)-linked HCC might be less likely to benefit from the immunotherapy alone. The limitation of the effect of the immunotherapy might be owing to the impaired T cell activation in MAFLD patients, which could be well explained by a dysfunctional gut-liver axis. Gut microbiota and their metabolites including several bile acids could contribute to modulating the responses of the immune checkpoint immunotherapy. Roles of gut microbiota in the development of cancers have expected great interest in the latest studies. Here, an interplay between the gut and liver has been presented, which might suggest to affect the efficacy of immune checkpoint immunotherapy against HCC
Some adverse actions of chlorothalonil at sublethal levels in rat thymic lymphocytes : Its relation to Zn2+
Chlorothalonil, a polychlorinated aromatic fungicide, is considered non-toxic to small mammals. However, chlorothalonil inactivates sulfhydryl enzymes and depletes cellular glutathione. Chlorothalonil increases intracellular Zn2+ concentration ([Zn2+]i) in mammalian cells possibly because intracellular Zn2+ is released via zinc-thiol/disulfide interchange. The effects of chlorothalonil at sublethal concentrations on the cellular content of nonprotein thiols ([NPT]i) and [Zn2+]i were examined using flow cytometry in rat thymocytes. Low concentrations (0.3–1 μM) of chlorothalonil increased, but high concentrations (3–10 μM) decreased [NPT]i. These effects of chlorothalonil were partly attenuated by an intracellular Zn2+ chelator. Chlorothalonil at 0.3–10 μM increased [Zn2+]i in a concentration-dependent manner, which was largely dependent on the release of intracellular Zn2+. Both the decrease in [NPT]i and increase in [Zn2+]i increase the vulnerability of cells to oxidative stress. Chlorothalonil at 1–10 μM potentiated the cytotoxicity of H2O2 (300 μM). It was also the case for 10 μM pentachloronitrobenzene, but not 10 μM pentachlorophenol. In conclusion, chlorothalonil at low (sublethal) micromolar concentrations is cytotoxic to mammalian cells under oxidative stress
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