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Multilayer diffraction gratings are designed to improve the detection limit and sensitivity of soft x-ray flat-field spectrographs in the region of 300-1000 eV, placing emphasis on Fe-L (705 eV), Cu-L (930 eV), and Zn-L (1012 eV) emissions. For this purpose, spectral flux was used as the performance index, which is proportional to the amount of optical flux incident into a detector and correlated with detection sensitivity. A super-mirror-type W/B4C multilayer coating [Koike et al., Rev.Sci. Instrum. 94, 045109 (2023)] was employed to improve diffraction efficiency in a wide energy region. The unique feature of the multilayer structure is that the average refractive index and the period length of W/B4C layer pairs are increased from the bottom to top layers. In addition, the incidence angle was reduced to 86.03° from 88.65° and the nominal groove density was increased to 3200 lines/mm from 2400 lines/mm of our previous design, to improve spectral flux while maintaining dispersion and spectral resolution. A holographic varied-line-spacing spherical grating and a soft x-ray flat-field spectrograph were designed, using the aspherical-wavefront-recording method, assuming the nominal grating constant and incident angle described above. The numerical simulation results showed that the spectrograph employing the newly designed grating with the W/B4C multilayer indicated 3.2-8.2 times higher spectral flux compared with those using the previously designed grating while keeping the same spectral resolution.
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A soft x-ray varied-line-spacing (VLS) laminar-type spherical grating with a super-mirror-type (SMT) multilayer was designed for a soft x-ray high resolution flat-field spectrograph in a region of 2-4 keV. The effective groove density of the designed VLS grating is 3200 lines/mm, and the local groove density varies from 2700 to 3866 lines/mm. The geometrical imaging property was evaluated by numerical calculations. The resolving power estimated by means of ray tracing was up to â¼103. For the evaluation of diffraction efficiency, the SMT multilayer structure designed for 3200 lines/mm in our previous work, Koike et al., Rev. Sci. Instrum. 94, 045109 (2023), was employed, and the numerical calculation was performed considering the local groove density of VLS grooves and the local incidence angle being affected by the curvature of the spherical surface and the geometrical relation between the source and incidence point on the grating. The results showed that the SMT multilayer-coated grating exhibited about an order of magnitude higher diffraction efficiency compared with an Au-coated grating.
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Soft x-ray diffraction gratings coated with a supermirror-type multilayer were designed to enhance diffraction efficiency in the energy range of 2-4 keV by means of numerical calculations. The optimized groove depth and incidence angle are 2.05 nm and 88.65°, respectively, for the grating having a groove density of 3200 grooves/mm. Regarding the multilayer structure, the optimum number of B4C/W layers pair was 11 and the thickness of B4C was increased from bottom to top, while that of W was kept constant. The replacement of the top layer of W by either Co, Cr, or Ni was an effective means of obtaining uniform diffraction efficiency. In the region of 2-4 keV, the calculated diffraction efficiency of the designed gratings was up to â¼5.3%, on average, and almost eight times larger than that of â¼0.7% of an Au coated grating.
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Laminar-type spherical diffraction gratings overcoated with carbon-based materials were designed, fabricated, and evaluated for the purpose of enhancing the analytical sensitivity of the flat-field spectrograph in a vacuum ultraviolet region of 35-110 eV. As the design benchmark for numerical calculations, diffraction efficiency (DE) and spectral flux, which are defined by the product of the DE and numerical aperture and correlate with the analytical sensitivity of the spectrograph, were used. To simplify the feasibility study on the overcoating effects, we assumed a laminar-type grating having a grating constant of 1/1000 mm and coated with a Au layer of 30.0 nm thickness and an incidence angle of 84.0°. The optimized groove depth and duty ratio were 30.0 nm and 0.3, respectively. In addition, the optimum thicknesses of the overcoating layer were 44, 46, 24, and 30 nm for B4C, C, diamond-like-carbon, and SiC, respectively. Based on these results, we have fabricated a varied-line-spacing holographic grating overcoated with B4C with a thickness of 47 nm. For the experimental evaluation, we used the light source of Mg-L and Al-L emissions excited by the electron beam generated from an electron microscope, an objective flat-field spectrograph, and a CCD imaging detector. The experimental results showed that the spectrograph employing a new grating overcoated with the B4C layer indicated almost the same spectral resolution and 2.9-4.2 times higher analytical sensitivity compared with those obtained with a previously designed Au-coated grating having a grating constant of 1/1200 mm and used at an incidence of 86.0°.
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BACKGROUND AND PURPOSE: In patients with ischemic stroke, DWI lesions can occasionally be reversed by reperfusion therapy. This study aimed to ascertain the relationship between ADC levels and DWI reversal in patients with acute ischemic stroke who underwent recanalization treatment. MATERIALS AND METHODS: We conducted a retrospective cohort study in patients with acute ischemic stroke who underwent endovascular mechanical thrombectomy with successful recanalization between April 2017 and March 2021. DWI reversal was assessed through follow-up MR imaging approximately 24 hours after treatment. RESULTS: In total, 118 patients were included. DWI reversal was confirmed in 42 patients. The ADC level in patients with reversal was significantly higher than that in patients without reversal. Eighty-three percent of patients with DWI reversal areas had mean ADC levels of ≥520 × 10-6 mm2/s, and 71% of patients without DWI reversal areas had mean ADC levels of <520 × 10-6 mm2/s. The mean ADC threshold was 520 × 10-6 mm2/s with a sensitivity and specificity of 71% and 83%, respectively. In multivariate analysis, the mean ADC level (OR, 1.023; 95% CI, 1.013-1.033; P < .0001) was independently associated with DWI reversal. Patients with DWI reversal areas had earlier neurologic improvement (NIHSS at 7 days) than patients without reversal areas (P < .0001). CONCLUSIONS: In acute ischemic stroke, the ADC value is independently associated with DWI reversal. Lesions with a mean ADC of ≥520 × 10-6 mm2/s are salvageable by mechanical thrombectomy, and DWI reversal areas regain neurologic function. The ADC value is easily assessed and is a useful tool to predict viable lesions.
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Isquemia Encefálica , AVC Isquêmico , Acidente Vascular Cerebral , Isquemia Encefálica/complicações , Isquemia Encefálica/diagnóstico por imagem , Isquemia Encefálica/cirurgia , Imagem de Difusão por Ressonância Magnética , Humanos , AVC Isquêmico/diagnóstico por imagem , AVC Isquêmico/cirurgia , Estudos Retrospectivos , Acidente Vascular Cerebral/complicações , Acidente Vascular Cerebral/diagnóstico por imagem , Acidente Vascular Cerebral/cirurgia , TrombectomiaRESUMO
We have grown thin films of CaAgAs by molecular beam epitaxy, which was theoretically proposed to be a topological insulator. The temperature dependence of resistivity and the carrier concentration at 4 K were similar to the reported results of bulk samples. However, the magnetoresistance exhibited a steep increase at low magnetic fields, a behavior not observed for bulk samples. This steep increase of resistivity is ascribable to the weak antilocalization effect and provides clues to the nature of the topological surface state of CaAgAs.
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BACKGROUND AND PURPOSE: Whether the neuromelanin-positive substantia nigra pars compacta area (NM-SNc) on neuromelanin magnetic resonance imaging (NM-MRI) and the specific binding ratio (SBR) on 123 I-N-v-fluoropropyl-2b-carbomethoxy3b-(4-iodophenyl)nortropane single photon emission computed tomography (DaT-SPECT) can be correlated with motor fluctuations (MFs) in advanced Parkinson's disease (PD) was investigated. METHODS: Thirty-five PD patients (60 ± 13 years) and 23 healthy individuals as controls (59 ± 19 years) were enrolled. The relationships between NM-MRI and DaT-SPECT were prospectively examined in two subgroups divided according to the presence or absence of MFs. Multivariate analysis was performed using the Cox proportional hazard model to screen for association factors. RESULTS: The NM-SNc size was correlated with the SBR (Spearman's ρ = 0.43, P < 0.05). The NM-SNc size was significantly reduced in PD with MFs compared with the subgroup without (P < 0.001), whereas the SBR did not significantly differ between the groups. NM-SNc size was a significant association factor for MFs (hazard ratio 0.94, P = 0.04). In receiver operating characteristic analysis of the factors for MF occurrence, the area under the receiver operating characteristic curve of the NM-SNc size showed a significant difference of 0.89 (P < 0.05) but no significant difference was found in the SBR. CONCLUSIONS: NM-SNc size was significantly correlated with the SBR in PD, but several factors in advanced PD were more closely associated with NM-SNc size than the SBR. NM-MRI might reflect the status of advanced PD more accurately than DaT-SPECT. Therefore, NM-MRI appears to provide a better marker for discriminating advanced PD than DaT-SPECT.
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Melaninas/análise , Doença de Parkinson/diagnóstico , Tomografia Computadorizada de Emissão de Fóton Único/métodos , Idoso , Idoso de 80 Anos ou mais , Biomarcadores , Encéfalo/diagnóstico por imagem , Feminino , Humanos , Imageamento por Ressonância Magnética , Masculino , Pessoa de Meia-Idade , Transtornos dos Movimentos/etiologia , Transtornos dos Movimentos/fisiopatologia , Estudos Prospectivos , Valores de ReferênciaRESUMO
[This corrects the article DOI: 10.1186/s40364-017-0099-2.].
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A quantum critical point (QCP) is currently being conjectured for the BaFe2(As1-x P x )2 system at the critical value x c ≈ 0.3. In the proximity of a QCP, all thermodynamic and transport properties are expected to scale with a single characteristic energy, given by the quantum fluctuations. Such a universal behavior has not, however, been found in the superconducting upper critical field H c2. Here we report H c2 data for epitaxial thin films extracted from the electrical resistance measured in very high magnetic fields up to 67 Tesla. Using a multi-band analysis we find that H c2 is sensitive to the QCP, implying a significant charge carrier effective mass enhancement at the doping-induced QCP that is essentially band-dependent. Our results point to two qualitatively different groups of electrons in BaFe2(As1-x P x )2. The first one (possibly associated to hot spots or whole Fermi sheets) has a strong mass enhancement at the QCP, and the second one is insensitive to the QCP. The observed duality could also be present in many other quantum critical systems.
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Fe-based superconductors (FBS) present a large variety of compounds whose properties are affected to different extents by their crystal structures. Amongst them, the REFeAs(O,F) (RE1111, RE being a rare-earth element) is the family with the highest critical temperature Tc but also with a large anisotropy and Josephson vortices as demonstrated in the flux-flow regime in Sm1111 (Tc â¼ 55 K). Here we focus on the pinning properties of the lower-Tc Nd1111 in the flux-creep regime. We demonstrate that for H//c critical current density Jc at high temperatures is dominated by point-defect pinning centres, whereas at low temperatures surface pinning by planar defects parallel to the c-axis and vortex shearing prevail. When the field approaches the ab-planes, two different regimes are observed at low temperatures as a consequence of the transition between 3D Abrikosov and 2D Josephson vortices: one is determined by the formation of a vortex-staircase structure and one by lock-in of vortices parallel to the layers. This is the first study on FBS showing this behaviour in the full temperature, field, and angular range and demonstrating that, despite the lower Tc and anisotropy of Nd1111 with respect to Sm1111, this compound is substantially affected by intrinsic pinning generating a strong ab-peak in Jc.
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A grazing incidence condenser is developed for objectives with large numerical aperture working in Carbon-window wavelength region (λ=4.4-5.0 nm) with the use of a point light source. The condenser is composed of four pieces of toroidal mirrors and a piece of the mirror was fabricated to evaluate the performance of the mirror. The radii of the toroidal mirror are determined by ray-trace calculation, and each radius of the mirror substrate and the roughness of the polished surface were evaluated to satisfy the designed parameter. A Co/C reflection multilayer is also designed to reflect soft x-ray light at 4.5 nm wavelength, and the reflection multilayer was deposited on the mirror surface. Measured reflectance of the toroidal mirror with the reflection multilayer is higher than 0.32 at 4.5 nm wavelength.
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Most patients diagnosed with tongue carcinoma undergo surgical resection and reconstructive surgery to preserve tongue mobility and swallowing functions. Twenty-four patients who underwent a total or subtotal glossectomy and surgical reconstruction were evaluated for residual taste sensation. The graded filter paper test for all four tastes (sweet, salt, sour, and bitter) was performed on the posterior wall of the oropharynx and on tongue remnants if they were visible from the mouth. Eleven of the 24 patients were aware of their taste disorder after surgery. Four patients with more than 1/2 residual tongue base had no taste complaints, whereas seven of 14 patients with less than 1/3 residual tongue base reported taste abnormalities. Patients who could only tolerate a poor diet or tube feeding tended to have taste complaints (P=0.017). The taste test showed that the taste threshold of the residual tongue was significantly lower compared to controls. The taste threshold was significantly correlated with the remaining volume of tongue base. Patients with >1/2 the tongue base remaining had good taste sensation, whereas those with <1/3 residual tissue had impaired taste. This study suggests that glossectomy strategies aimed at preserving at least half the tongue base may substantially reduce dysgeusia in the patients.
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Glossectomia/métodos , Procedimentos de Cirurgia Plástica/métodos , Distúrbios do Paladar/diagnóstico , Distúrbios do Paladar/prevenção & controle , Neoplasias da Língua/cirurgia , Adulto , Idoso , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Limiar Gustativo , Língua/cirurgia , Resultado do TratamentoRESUMO
Electron correlation often produces a variety of electrically insulating states caused by self-organization of electrons, which are particularly stable at commensurate fillings. Although collapsing such ordered states by minute external stimuli has been a key strategy toward device applications, it is difficult to access their true electronic phase boundaries due to the necessity of fine-tuning of material parameters. Here, we demonstrate the ambipolar resistance switching in Pr(1-x)Sr(x)MnO3 thin films (x = 0.5; an effectively 1/4-filled state) by quasi-continuous control of the doping level x and band-width W using gate-voltage and magnetic field, enabled by the extreme electric-field formed at the nanoscale interface generated in an electrolyte-gated transistor. An electroresistance peak with unprecedented steepness emerges on approaching a critical point in the x-W phase diagram. The technique opens a new route to Mott-insulator based transistors and to discovering singularities hitherto unnoticed in conventional bulk studies of strongly correlated electron systems.
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BACKGROUND: An increased body mass index (BMI) is significantly associated with favourable prognosis in renal cell carcinoma (RCC). This study investigated the associations among sex, BMI, and prognosis in clear cell RCC patients. METHODS: We retrospectively analysed 435 patients with clear cell RCC who underwent a nephrectomy. The associations among sex, BMI, clinicopathologic factors, and cancer-specific survival (CSS) were analysed. RESULTS: As a continuous variable, increased BMI was associated with higher CSS rate by univariate analysis in the whole population (hazard ratio, 0.888 per kg m(-2); 95% confidence interval, 0.803-0.982; P=0.021). A sub-population analysis by sex demonstrated that BMI was significantly associated with CSS in men (P=0.004) but not in women (P=0.725). Multivariate analysis revealed BMI to be an independent predictor of CSS in only men. CONCLUSION: Body mass index was significantly associated with clear cell RCC prognosis. However, the clinical value of BMI may be different between men and women.
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Fatores Etários , Índice de Massa Corporal , Carcinoma de Células Renais/mortalidade , Neoplasias Renais/mortalidade , Caracteres Sexuais , Adulto , Idoso , Idoso de 80 Anos ou mais , Carcinoma de Células Renais/metabolismo , Carcinoma de Células Renais/cirurgia , Feminino , Humanos , Neoplasias Renais/metabolismo , Neoplasias Renais/cirurgia , Masculino , Pessoa de Meia-Idade , Nefrectomia , Prognóstico , Estudos Retrospectivos , Taxa de Sobrevida , Resultado do TratamentoRESUMO
This study aimed to evaluate the efficacy and safety of an extended-release tablet formulation of pramipexole (PPX-ER) given once daily when switched from an immediate-release tablet formulation (PPX-IR) given 3 times daily. This open-label study included 29 patients with idiopathic Parkinson's disease (PD) who were followed for 8 weeks. Primary endpoints were Unified Parkinson's Disease Rating Scale (UPDRS) part III score, a physician evaluation of motor symptoms; nocturnal and early morning symptoms (NEMS) score, based on the results for 4 items in the Parkinson's Disease Sleep Scale and the Movement Disorder Society - sponsored revision of the UPDRS; and patients' formulation preference, determined through questionnaires. Secondary endpoints were nocturnal sleep disturbance, evaluated using the revised version of the Parkinson's Disease Sleep Scale (PDSS-2); quality of life, evaluated using the 39-item Parkinson's Disease Questionnaire (PDQ-39); Clinical Global Impression-Improvement (CGI-I) score; Patient Global Impression-Improvement (PGI-I) score; and caregiver formulation preference. UPDRS part III score (mean ± SD) was significantly decreased after 4 weeks (13.9 ± 7.3; P=0.030) and 8 weeks (12.2 ± 7.3; P<0.001) from baseline (15.3 ± 7.0). However, no significant change was found in NEMS scale, PDSS-2 or PDQ-39 scores. After 8 weeks, the responder rates based on CGI-I and PGI-I scores were 27.6% and 20.7%, respectively. As a result of the questionnaire, 63.0% of patients and 58.8% of their caregivers preferred PPX-ER. A non-serious drug-related adverse event (diarrhea) was observed in one patient. In conclusion, PPX-ER can be considered as a useful treatment option when PPX-IR needs to be switched to other dopamine agonists.This study is registered with UMIN-CTR (UMIN000006521).
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Antiparkinsonianos/uso terapêutico , Benzotiazóis/uso terapêutico , Doença de Parkinson/tratamento farmacológico , Qualidade de Vida , Antiparkinsonianos/administração & dosagem , Antiparkinsonianos/efeitos adversos , Benzotiazóis/administração & dosagem , Benzotiazóis/efeitos adversos , Cuidadores/estatística & dados numéricos , Preparações de Ação Retardada , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Doença de Parkinson/fisiopatologia , Preferência do Paciente , Pramipexol , Inquéritos e Questionários , Resultado do TratamentoRESUMO
We investigate two- and three-electron spin blockade in three vertical quantum dots (QDs) coupled in series. Two-electron spin blockade is found in a region where sequential tunneling through all QDs is forbidden but tunneling involving virtual hopping through an empty QD is allowed. It is observed only for the hole cycle with a distinct bias threshold for access to the triplet state. Three-electron spin blockade involving the quadruplet state is observed for nonequibilium conditions where sequential tunneling is allowed and the triplet state is accessible. Our results shine light on the importance of the nonequibilium conditions to obtain sufficient population of triplet and quadruplet states necessary for spin blockade.
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In the classic transistor, the number of electric charge carriers--and thus the electrical conductivity--is precisely controlled by external voltage, providing electrical switching capability. This simple but powerful feature is essential for information processing technology, and also provides a platform for fundamental physics research. As the number of charges essentially determines the electronic phase of a condensed-matter system, transistor operation enables reversible and isothermal changes in the system's state, as successfully demonstrated in electric-field-induced ferromagnetism and superconductivity. However, this effect of the electric field is limited to a channel thickness of nanometres or less, owing to the presence of Thomas-Fermi screening. Here we show that this conventional picture does not apply to a class of materials characterized by inherent collective interactions between electrons and the crystal lattice. We prepared metal-insulator-semiconductor field-effect transistors based on vanadium dioxide--a strongly correlated material with a thermally driven, first-order metal-insulator transition well above room temperature--and found that electrostatic charging at a surface drives all the previously localized charge carriers in the bulk material into motion, leading to the emergence of a three-dimensional metallic ground state. This non-local switching of the electronic state is achieved by applying a voltage of only about one volt. In a voltage-sweep measurement, the first-order nature of the metal-insulator transition provides a non-volatile memory effect, which is operable at room temperature. Our results demonstrate a conceptually new field-effect device, extending the concept of electric-field control to macroscopic phase control.
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Aharonov-Bohm (AB) oscillations are studied for a parallel-coupled vertical double quantum dot with a common source and drain electrode. We observe AB oscillations of current via a one-electron bonding state as the ground state and an antibonding state as the excited state. As the center gate voltage becomes more negative, the oscillation period is clearly halved for both the bonding and antibonding states, and the phase changes by half a period for the antibonding state. This result can be explained by a calculation that takes account of the indirect interdot coupling via the two electrodes.
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We report on THz emission measurements and low temperature scanning laser imaging of Bi2Sr2CaCu2O8 intrinsic Josephson junction stacks. Coherent emission is observed at large dc input power, where a hot spot and a standing wave, formed in the "cold" part of the stack, coexist. By changing bias current and bath temperature, the emission frequency can be varied by more than 40%; the variation matches the Josephson-frequency variation with voltage. The linewidth of radiation is much smaller than expected from a purely cavity-induced synchronization. Thus, an additional mechanism seems to play a role. Some scenarios, related to the presence of the hot spot, are discussed.