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1.
Molecules ; 26(20)2021 Oct 14.
Artigo em Inglês | MEDLINE | ID: mdl-34684790

RESUMO

In this study, hydrogen boride films are fabricated by ion-exchange treatment on magnesium diboride (MgB2) films under ambient temperature and pressure. We prepared oriented MgB2 films on strontium titanate (SrTiO3) substrates using pulsed laser deposition (PLD). Subsequently, these films were treated with ion exchangers in acetonitrile solution. TOF-SIMS analysis evidenced that hydrogen species were introduced into the MgB2 films by using two types of ion exchangers: proton exchange resin and formic acid. According to the HAXPES analysis, negatively charged boron species were preserved in the films after the ion-exchange treatment. In addition, the FT-IR analysis suggested that B-H bonds were formed in the MgB2 films following the ion-exchange treatment. The ion-exchange treatment using formic acid was more efficient compared to the resin treatment; with respect to the amount of hydrogen species introduced into the MgB2 films. These ion-exchanged films exhibited photoinduced hydrogen release as observed in a powder sample. Based on the present study, we expect to be able to control the morphology and hydrogen content of hydrogen boride thin films by optimising the ion-exchange treatment process, which will be useful for further studies and device applications.

2.
J Chem Phys ; 152(23): 231101, 2020 Jun 21.
Artigo em Inglês | MEDLINE | ID: mdl-32571043

RESUMO

Light irradiation onto a semiconductor generates heat; however, its electronic structure under high temperature has not yet been well investigated. In this study, we have carefully examined the temperature dependence on the bandgap of simple metal oxides, which are well-known photocatalysts, i.e., TiO2, CeO2, Nb2O5, SnO2 Ta2O5, WO3, ZnO, and ZrO2, using operando UV-visible spectroscopy under controlled temperature (from room temperature to 500 °C). Consequently, a linear decrease in bandgap was seen as a function of temperature with a different slope for each semiconductor. We found that the slope was dependent on the bonding distance between metal and oxygen. This finding is essential to develop a photocatalyst used under the condition involving photo-thermal effect.

3.
Phys Rev Lett ; 123(11): 113201, 2019 Sep 13.
Artigo em Inglês | MEDLINE | ID: mdl-31573273

RESUMO

We experimentally and theoretically determine the magic wavelength of the (5s^{2})^{1}S_{0}-(5s5p)^{3}P_{0} clock transition of ^{111}Cd to be 419.88(14) and 420.1(7) nm. To perform Lamb-Dicke spectroscopy of the clock transition, we use narrow-line laser cooling on the ^{1}S_{0}-^{3}P_{1} transition to cool the atoms to 6 µK and load them into an optical lattice. Cadmium is an attractive candidate for optical lattice clocks because it has a small sensitivity to blackbody radiation and its efficient narrow-line cooling mitigates higher order light shifts. We calculate the blackbody shift, including the dynamic correction, to be fractionally 2.83(8)×10^{-16} at 300 K, an order of magnitude smaller than that of Sr and Yb. We also report calculations of the Cd ^{1}P_{1} lifetime and the ground state C_{6} coefficient.

4.
Phys Rev Lett ; 123(22): 222501, 2019 Nov 29.
Artigo em Inglês | MEDLINE | ID: mdl-31868403

RESUMO

The low-lying isomeric state of ^{229}Th provides unique opportunities for high-resolution laser spectroscopy of the atomic nucleus. We determine the energy of this isomeric state by taking the absolute energy difference between the excitation energy required to populate the 29.2-keV state from the ground state and the energy emitted in its decay to the isomeric excited state. A transition-edge sensor microcalorimeter was used to measure the absolute energy of the 29.2-keV γ ray. Together with the cross-band transition energy (29.2 keV→ground) and the branching ratio of the 29.2-keV state measured in a recent study, the isomer energy was determined to be 8.30±0.92 eV. Our result is in agreement with the latest measurements based on different experimental techniques, which further confirms that the isomeric state of ^{229}Th is in the laser-accessible vacuum ultraviolet range.

5.
Phys Rev Lett ; 114(10): 105304, 2015 Mar 13.
Artigo em Inglês | MEDLINE | ID: mdl-25815943

RESUMO

The transverse acoustic impedance of superfluid ^{3}He was measured in the A1 and A2 phases up to 13 T to investigate the surface states in nonunitary superfluids. The temperature dependence of the impedance was much larger in the A1 phase than in the A2 phase. This nonsymmetric behavior indicates that momentum exchange with walls for spin-down surface states is quite different from that for spin-up surface states. The spin-dependent response might be a reflection of an essential feature of the nonunitary states where gap amplitudes depend on spin states. Weak-coupling theories ignore any spin-dependent processes and do not account for the nonsymmetric behavior.

6.
Inorg Chem ; 53(12): 5878-80, 2014 Jun 16.
Artigo em Inglês | MEDLINE | ID: mdl-24853637

RESUMO

Learning from serendipitous assembly, we have prepared a new family of designed 3d-4f Mn6Ln complexes. The dynamics of relaxation of the magnetization via alternating-current magnetic susceptibility for the new Mn6Ln complexes 1 (Ln = La), 2 (Ln = Tb), and 4 (Ln = Dy) have been studied down to 0.2 K.

7.
Sarcoidosis Vasc Diffuse Lung Dis ; 30(1): 43-51, 2013 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-24003534

RESUMO

BACKGROUND: The serum Krebs von der Lungen-6 (KL-6) level is a useful marker correlated with the severity of various interstitial lung diseases. There have been few reports about the clinical characteristics of organizing pneumonia (OP) associated with the serum KL-6 levels. OBJECTIVE: This study was performed to determine whether the serum KL-6 levels can help determine the optimal treatment for OP. DESIGNS: Patients diagnosed with OP by clinical, radiological and histopathological findings were retrospectively reviewed. The OP patients were classified into two groups based on their serum KL-6 levels: normal KL-6 and high KL-6 groups. The two groups were compared with regard to their clinical and radiological data and therapeutic response one month after the start of treatment. RESULTS: The clinical records of twenty-two patients diagnosed with OP were reviewed. The serum KL-6 level was elevated in 11 of the 22 patients. There were no obvious differences in the clinical data between the two groups, although patients in the normal KL-6 group tended to have a fever. There were no significant differences in the chest X-ray (CXR) score or computed tomography (CT) score between the two groups. The CXR scores were correlated with the serum KL-6 levels. At 1 month after the diagnosis, 11 patients who needed treatment with prednisolone were included in the high KL-6 group. CONCLUSIONS: Patients with normal KL-6 levels showed lower CXR and CT scores. The serum KL-6 level on admission is a useful marker to judge the need for corticosteroid treatment in OP patients.


Assuntos
Biomarcadores/sangue , Pneumonia em Organização Criptogênica/sangue , Mucina-1/sangue , Corticosteroides/uso terapêutico , Broncoscopia , Pneumonia em Organização Criptogênica/diagnóstico , Pneumonia em Organização Criptogênica/diagnóstico por imagem , Pneumonia em Organização Criptogênica/tratamento farmacológico , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Estudos Retrospectivos , Tomografia Computadorizada por Raios X
8.
J Intellect Disabil Res ; 57(1): 67-79, 2013 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-22233468

RESUMO

BACKGROUND: The ventral and dorsal streams are considered to be the brain substrates of vision for perception and action, respectively. Using the Developmental Test of Visual Perception (DTVP), the current study examined whether visual perceptual strengths and weaknesses in adults with intellectual disabilities (ID) were attributable to the dichotomy of the visual streams. METHOD: In study 1, DTVP performance was compared among mild, moderate and severe adult ID groups; study 2 contrasted adult ID groups with and without Down syndrome (DS). To prevent possible contamination by the Flynn effect, participants were matched by birth year with the norm of the DTVP original edition. RESULTS: Independent of the extent of ID among the three groups in study 1 and the aetiological group difference in study 2, relative strength was found for two DTVP tasks: eye-hand coordination and distinguishing target figures from interference background. Relative weakness was obtained in identifying a figural category. Participants with DS demonstrated exceptional weakness in discerning a target from either mirror-imaged or rotated alternatives, in addition to figural-category detection. CONCLUSIONS: Visual perceptual strengths and weaknesses in persons with ID were difficult to explain on the basis of two visual streams. An interpretation originating in a different research context (e.g. frontal-lobe dysfunction) appears to be required for explaining visual perceptual weaknesses in persons with ID. For persons with DS, strong frontal-lobe dysfunction with atypical lateralisation might be the pathological determinant of visual perceptual weaknesses.


Assuntos
Síndrome de Down/fisiopatologia , Lobo Frontal/fisiologia , Deficiência Intelectual/fisiopatologia , Transtornos da Visão/diagnóstico , Percepção Visual/fisiologia , Adulto , Estudos de Casos e Controles , Síndrome de Down/complicações , Feminino , Desenvolvimento Humano/fisiologia , Humanos , Deficiência Intelectual/complicações , Masculino , Análise por Pareamento , Pessoa de Meia-Idade , Índice de Gravidade de Doença , Transtornos da Visão/complicações , Vias Visuais/fisiologia , Adulto Jovem
9.
Mol Pharm ; 9(6): 1681-92, 2012 Jun 04.
Artigo em Inglês | MEDLINE | ID: mdl-22519912

RESUMO

The aim of the present study is to synthesize new mannosylated dextran derivative that can be labeled with Tc-99m for potential use in sentinel lymph node detection (SLND). The compound was designed to have a dextran with molecular weight of 10 kDa as a backbone, mannose for binding to mannose receptors of the lymph node and S-derivatized cysteine as a suitable chelator for labeling with [(99m)Tc(H(2)O)(3)(CO)(3)](+) precursor. Reaction of allyl bromide with dextran (MW 11800) yielded the intermediate allyl-dextran (1) with about 40% coupling. Addition of cysteine to allyl-dextran resulted in the S-derivatized cysteine, compound DC15 (2). The final product DCM20 (3) was obtained in good yield after in situ hydrolysis and activation of cyanomethyl tetraacetyl-1-thio-d-mannopyranoside and coupling to DC15. All derivatives were purified by ultrafiltration and characterized by NMR. DC15 and DCM20 were quantitatively labeled with (99m)Tc (>95% radiochemical purity) using the fac-[(99m)Tc(OH(2))(3)(CO)(3)](+) precursor and ligand concentration of 1.5 × 10(-6) M at neutral pH. Both (99m)Tc-labeled compounds (99m)Tc(CO)(3)-DC15 (6) and (99m)Tc(CO)(3)-DCM20 (7) remained stable after 6 h incubation at 37 °C in the presence of excess histidine or cysteine, as well as even after 20-fold dilution and incubation for 24 h at room temperature. The characterization of the compounds 6 and 7 was performed by comparing their HPLC radiochromatograms with those of their rhenium surrogates Re(CO)(3)-DC15 (4) and Re(CO)(3)-DCM20 (5) respectively that were prepared using the precursor [NEt(4)](2)fac-[ReBr(3)(CO)(3)] and characterized by IR and NMR spectroscopy. When injected subcutaneously from the foot pad of mice, (99m)Tc-labeled mannosylated dextran (7) showed accumulation in the popliteal lymph node (SLN in this model) higher than that of non-mannosylated analogue (6) and the (99m)Tc-phytate serving as standard. Compound 7 also exhibited lower radioactivity levels at the injection site compared to (99m)Tc-phytate. The SPECT/CT studies in mice confirmed that 7 accumulated in the popliteal lymph node allowing its clear visualization. The present findings demonstrate that compound 7 ((99m)Tc(CO)(3)-DCM20) is promising and merits further evaluation as a radiopharmaceutical for sentinel lymph node detection.


Assuntos
Quelantes/química , Quelantes/síntese química , Dextranos/química , Dextranos/síntese química , Linfonodos/metabolismo , Manose/química , Compostos de Organotecnécio/química , Animais , Humanos , Masculino , Camundongos , Imagem Multimodal , Tomografia por Emissão de Pósitrons , Biópsia de Linfonodo Sentinela/métodos , Tomografia Computadorizada por Raios X
10.
Nature ; 444(7121): 909-12, 2006 Dec 14.
Artigo em Inglês | MEDLINE | ID: mdl-17167481

RESUMO

The magnetic properties of (3)He in its various phases originate from the interactions among the nuclear spins. The spin-polarized 'ferromagnetic' superfluid (3)He A(1) phase (which forms below 3 mK between two transition temperatures, T(c1) and T(c2), in an external magnetic field) serves as a material in which theories of fundamental magnetic processes and macroscopic quantum spin phenomena may be tested. Conventionally, the superfluid component of the A(1) phase is understood to contain only the majority spin condensate, having energetically favoured paired spins directed along the external field and no minority spin condensate having paired spins in the opposite direction. Because of difficulties in satisfying both the ultralow temperature and high magnetic field required to produce a substantial phase space, there exist few studies of spin dynamics phenomena that could be used to test the conventional view of the A(1) phase. Here we develop a mechanical spin density detector that operates in the required regime, enabling us to perform measurements of spin relaxation in the A(1) phase as a function of temperature, pressure and magnetic field. Our mechanical spin detector is based in principle on the magnetic fountain effect; spin-polarized superfluid motion can be induced both magnetically and mechanically, and we demonstrate the feasibility of increasing spin polarization by a mechanical spin filtering process. In the high temperature range of the A(1) phase near T(c1), the measured spin relaxation time is long, as expected. Unexpectedly, the spin relaxation rate increases rapidly as the temperature is decreased towards T(c2). Our measurements, together with Leggett-Takagi theory, demonstrate that a minute presence of minority spin pairs is responsible for this unexpected spin relaxation behaviour. Thus, the long-held conventional view that the A(1) phase contains only the majority spin condensate is inadequate.

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