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1.
Sci Rep ; 12(1): 18957, 2022 Nov 08.
Artigo em Inglês | MEDLINE | ID: mdl-36348085

RESUMO

We investigated the doping and temperature evolutions of the optical response of Sr3(Ir1-xMnx)2O7 single crystals with 0 ≤ x ≤ 0.36 by utilizing infrared spectroscopy. Substitution of 3d transition metal Mn ions into Sr3Ir2O7 is expected to induce an insulator-to-metal transition via the decrease in the magnitude of the spin-orbit coupling and the hole doping. In sharp contrast, our data reveal the resilience of the spin-orbit coupling and the incoherent character of the charge transport. Upon Mn substitution, an incoherent in-gap excitation at about 0.25 eV appeared with the decrease in the strength of the optical transitions between the effective total angular momentum Jeff bands of the Ir ions. The resonance energies of the optical transitions between the Jeff bands which are directly proportional to the magnitude of the spin-orbit coupling hardly varied. In addition to these evolutions of the low-energy response, Mn substitution led to the emergence of a distinct high-energy optical excitation at about 1.2 eV which is larger than the resonance energies of the optical transitions between the Jeff bands. This observation indicates that the Mn 3d states are located away from the Ir 5d states in energy and that the large difference in the on-site energies of the transition metal ions is responsible for the incoherent charge transport and the robustness of the spin-orbit coupling. The effect of Mn substitution was also registered in the temperature dependence of the electronic response. The anomaly in the optical response of the parent compound observed at the antiferromagnetic transition temperature is notably suppressed in the Mn-doped compounds despite the persistence of the long-range antiferromagnetic ordering. The suppression of the spin-charge coupling could be related to charge disproportionation of the Ir ions.

2.
Rhinology ; 60(3): 200-206, 2022 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-35174812

RESUMO

BACKGROUND: Little is known about the occurrence of gustatory dysfunction (GD) in relation to different aetiologies of olfactory dysfunction (OD) as assessed by psychophysical chemosensory tests. The aim of this study was to analyse gustatory function in patients with OD and to investigate clinical factors associated with GD. METHODS: A total of 742 individuals who underwent both olfactory and gustatory function tests at a tertiary medical centre from November 2019 to March 2021 were retrospectively enrolled. Olfactory and gustatory function were assessed by the YSK olfactory and gustatory function tests, respectively. Patients with OD were classified into four groups according to the aetiology: sinonasal disease, post-infection OD (PIOD), post-traumatic OD (PTOD), and others. Secondary outcomes included age, sex, smoking history, and alcohol history. RESULTS: Among the 488 patients with OD, 93 (19.1%) showed GD and 395 (80.9%) had normal gustatory function. Only 25 (9.8%) among 254 individuals with normosmia showed GD. Analyses of these frequencies revealed a significant association between OD and GD. In addition, the taste score was significantly lower in patients with OD than individuals with normosmia. The frequency of GD was significantly higher in patients with PTOD (53.6%) than in those with OD of other aetiologies (sinonasal disease, 6.7%; PIOD, 13.0%; others, 24.4%). In the multivariate analysis, age >=5 years and PTOD were associated with a high frequency of GD among patients with OD. CONCLUSIONS: The current study show that GD is significantly associated with OD. In particular, GD is more common in patients with PTOD than in those with OD of other aetiologies.


Assuntos
Transtornos do Olfato , Humanos , Pré-Escolar , Estudos Retrospectivos , Olfato , Distúrbios do Paladar/etiologia
3.
Phys Rev Lett ; 127(26): 267203, 2021 Dec 24.
Artigo em Inglês | MEDLINE | ID: mdl-35029465

RESUMO

Topological magnonic materials have attracted much interest because of the potential for dissipationless spintronic applications. Pyrochlore iridates are theoretically regarded as good candidates for designing topological magnon bands. However, experimental identification of topological magnon bands in pyrochlore iridates remains elusive. We explored this possibility in Y_{2}Ir_{2}O_{7} using Raman spectroscopy to measure both the single-magnon excitations and anomalous phonon shifts. From the single-magnon energies and tight-binding model calculations concerning the phonons, we determined the key parameters in the spin Hamiltonian. These confirm that Y_{2}Ir_{2}O_{7} hosts a nontrivial magnon band topology distinct from other pyrochlore iridate compounds. Our work demonstrates that pyrochlore iridates constitute a system in which the magnon band topology can be tailored and that Raman spectroscopy is a powerful technique to explore magnon band topology.

4.
Hum Exp Toxicol ; 40(1): 113-123, 2021 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-32757783

RESUMO

OBJECTIVES: Uremic pruritus is common in patients with chronic kidney disease (CKD). The retention of uremic solutes is thought to be associated with uremic pruritus. Meanwhile, activation of protease-activated receptor-2 (PAR-2) has been suggested to play an important role in pruritus. The present study was performed to investigate the effects of uremic solutes on the expression of PAR-2 in the skin. METHODS: Indoxyl sulfate (IS), p-cresol (PC), and uremic sera from CKD patients were used to stimulate PAR-2 expression in normal human epidermal keratinocytes (NHEKs). Also, NHEKs were additionally pretreated with soybean trypsin inhibitor to evaluate its inhibitory effect on PAR-2 expression. Patterns of cutaneous PAR-2 expression were investigated in skin samples from five CKD patients and CKD mice. RESULTS: In NHEKs, IS, PC, and sera from CKD patients significantly induced PAR-2 mRNA and protein expression. Soybean trypsin inhibitor significantly decreased PAR-2 mRNA and protein expression in NHEKs treated with IS, PC, and CKD sera. NHEKs treated with IS and PC exhibited significant increases in protease activity. Skin from both CKD patients and mice exhibited marked upregulation of PAR-2 expression compared to control skin. CONCLUSIONS: Results from the present study suggest that uremic solutes either directly or indirectly affect PAR-2 expression in the skin of CKD subjects, potentially playing an important role in the pathogenesis of uremic pruritus.


Assuntos
Cresóis/metabolismo , Indicã/metabolismo , Receptor PAR-2/metabolismo , Animais , Células Cultivadas , Humanos , Queratinócitos , Masculino , Camundongos , Regulação para Cima
5.
Sci Rep ; 10(1): 22340, 2020 Dec 18.
Artigo em Inglês | MEDLINE | ID: mdl-33339856

RESUMO

We report on optical spectroscopic study of the Sr3(Ir1-xRux)2O7 system over a wide doping regime. We find that the changes in the electronic structure occur in the limited range of the concentration of Ru ions where the insulator-metal transition occurs. In the insulating regime, the electronic structure associated with the effective total angular momentum Jeff = 1/2 Mott state remains robust against Ru doping, indicating the localization of the doped holes. Upon entering the metallic regime, the Mott gap collapses and the Drude-like peak with strange metallic character appears. The evolution of the electronic structure registered in the optical data can be explained in terms of a percolative insulator-metal transition. The phonon spectra display anomalous doping evolution of the lineshapes. While the phonon modes of the compounds deep in the insulating and metallic regimes are almost symmetric, those of the semiconducting compound with x = 0.34 in close proximity to the doping-driven insulator-metal transition show a pronounced asymmetry. The temperature evolution of the phonon modes of the x = 0.34 compound reveals the asymmetry is enhanced in the antiferromagnetic state. We discuss roles of the S = 1 spins of the Ru ions and charge excitations for the conspicuous lineshape asymmetry of the x = 0.34 compound.

6.
Eur J Appl Physiol ; 118(11): 2295-2305, 2018 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-30128852

RESUMO

This study investigated the effects of 9-week endurance cycling training on central fatigability and corticomotor excitability of the locomotor muscles. Fourteen healthy participants undertook three incremental fatiguing cycling tests to volitional exhaustion (EXH): (i) before training (PRE), (ii) after training at the same absolute power output as PRE (POSTABS) and (iii) after training at the same percentage of V̇O2max as PRE (POSTREL). At baseline (i.e. before cycling), every 5 min during cycling and immediately at EXH, a neuromuscular evaluation including a series of 5-s knee extensions at 100, 75 and 50% of maximal voluntary knee extension (MVC) was performed. During each contraction, transcranial magnetic and peripheral nerve stimuli were elicited to obtain motor evoked potential (MEP), silent period (SP) and compound muscle action potential (Mmax) and to calculate voluntary activation (VA). The MEP·Mmax-1 ratio recorded from vastus lateralis at 100 and 50% MVC did not show any difference between conditions. At 75% MVC, MEP exhibited significantly lower values in POSTABS and POSTREL compared to PRE at baseline (P = 0.022 and P = 0.011, respectively) as well as at 25% of time to EXH of PRE (P = 0.022) for POSTREL. No adaptations, either at baseline or during cycling, were observed for VA and SPs. In conclusion, endurance training may result in some adaptations in the corticomotor responses when measured at rest or with low level of fatigue, yet these adaptations do not translate into attenuation of central fatigue at a similar cycling workload or at exhaustion.


Assuntos
Ciclismo/fisiologia , Treino Aeróbico/métodos , Córtex Motor/fisiologia , Fadiga Muscular/fisiologia , Tratos Piramidais/fisiologia , Adulto , Estimulação Elétrica , Eletromiografia , Nervo Femoral/fisiologia , Humanos , Masculino , Contração Muscular/fisiologia , Consumo de Oxigênio/fisiologia , Músculo Quadríceps/fisiologia , Estimulação Magnética Transcraniana , Adulto Jovem
7.
Eur J Appl Physiol ; 118(11): 2281-2293, 2018 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-30121882

RESUMO

PURPOSE: The adaptations induced by endurance training on the neuromuscular function remain under investigation and, for methodological reasons, unclear. This study investigates the effects of cycling training on neuromuscular fatigue and its peripheral contribution measured during and immediately after cycling exercise. METHODS: Fourteen healthy men performed a fatigue test before a 9-week cycling program (PRE) and two tests after training: at the same absolute power output as PRE (POSTABS) and based on the post-training maximal aerobic power (POSTREL). Throughout the tests and at exhaustion (EXH), maximal voluntary contraction (MVC) and peripheral fatigue were assessed in the quadriceps muscle by electrical nerve stimulation [single twitch (Pt); high-frequency doublet (Db100) and low-to-high-frequency ratio (Db10:100)]. RESULTS: Time to EXH was longer in POSTABS than PRE (34 ± 5 vs. 27 ± 4 min, P < 0.001), and POSTREL tended to be longer than PRE (30 ± 6 min, P = 0.053). MVC and peripheral fatigue were overall less depressed in POSTABS than PRE at isotime. At EXH, MVC and Db10:100 were similarly reduced in all sessions (-37 to - 42% and - 30 to - 37%, respectively). Db100 tended to be less depressed in POSTABS than PRE (-40 ± 9 vs. - 48 ± 16%, P = 0.050) and in POSTREL than PRE (-39 ± 9%, P = 0.071). Pt decreased similarly in POSTABS and PRE (-52 ± 16 vs. - 54 ± 16%), but POSTREL tended to be less depressed than PRE (-48 ± 14%, P = 0.075). CONCLUSIONS: This study confirms fatigue attenuation at isotime after training. Yet lower or similar fatigue at EXH indicates that, unlike previously suggested, fatigue tolerance may not be upregulated after 9 weeks of cycling training.


Assuntos
Treino Aeróbico/métodos , Contração Muscular/fisiologia , Fadiga Muscular/fisiologia , Força Muscular/fisiologia , Resistência Física/fisiologia , Músculo Quadríceps/fisiologia , Adulto , Eletromiografia , Exercício Físico/fisiologia , Teste de Esforço , Humanos , Masculino , Consumo de Oxigênio/fisiologia , Adulto Jovem
8.
Aliment Pharmacol Ther ; 48(2): 206-218, 2018 07.
Artigo em Inglês | MEDLINE | ID: mdl-29863280

RESUMO

BACKGROUND: A novel potassium-competitive acid blocker, DWP14012, is in clinical development as a potential alternative to proton pump inhibitors for the treatment of acid-related diseases. AIMS: To evaluate the safety, tolerability, pharmacodynamics and pharmacokinetics of DWP14012 in humans. METHODS: A randomised, double-blind, double-dummy, placebo- and active-controlled, single- and multiple-ascending dose (SAD and MAD, respectively) study was conducted in healthy male subjects without Helicobacter pylori infection. Subjects randomly received a single oral dose of 10-320 mg DWP14012, esomeprazole (active comparator) or placebo in the SAD study (n = 72) and once daily doses of 20-160 mg DWP14012, esomeprazole or placebo for 7 days in the MAD study (n = 48; 8:2:2). Tolerability was evaluated using a microRNA-122 assay. Pharmacodynamics were evaluated through 24-hour gastric pH monitoring, and pharmacokinetics were evaluated plasma and urine DWP14012 concentrations. RESULTS: DWP14012 was generally well tolerated. The liver toxicity of DWP14012 was not higher than that of placebo after multiple oral administrations. DWP14012 showed rapid and sustained suppression of gastric acid secretion for 24 hours after dosing. Clear dose-response and exposure-response relationships were observed. Plasma concentrations of DWP14012 increased in a dose-proportional manner in the MAD study, whereas in the SAD study, DWP14012 did not significantly accumulate in the plasma. CONCLUSIONS: DWP14012 was well tolerated, and showed a rapid and long-lasting gastric acid suppression effect in healthy subjects. These results justify further investigation of DWP14012 in patients with acid-related disorders.


Assuntos
Aminas , Antiulcerosos , Pirróis , Administração Oral , Adulto , Aminas/administração & dosagem , Aminas/efeitos adversos , Aminas/farmacocinética , Aminas/farmacologia , Antiulcerosos/administração & dosagem , Antiulcerosos/efeitos adversos , Antiulcerosos/farmacocinética , Antiulcerosos/farmacologia , Ligação Competitiva , Relação Dose-Resposta a Droga , Método Duplo-Cego , Esomeprazol/administração & dosagem , Esomeprazol/efeitos adversos , Esomeprazol/farmacocinética , Voluntários Saudáveis , Humanos , Masculino , Pessoa de Meia-Idade , Placebos , Pirróis/administração & dosagem , Pirróis/efeitos adversos , Pirróis/farmacocinética , Pirróis/farmacologia , ATPase Trocadora de Sódio-Potássio/antagonistas & inibidores , Adulto Jovem
9.
Phys Rev Lett ; 120(13): 136402, 2018 Mar 30.
Artigo em Inglês | MEDLINE | ID: mdl-29694193

RESUMO

Strong charge-spin coupling is found in a layered transition-metal trichalcogenide NiPS_{3}, a van der Waals antiferromagnet, from studies of the electronic structure using several experimental and theoretical tools: spectroscopic ellipsometry, x-ray absorption, photoemission spectroscopy, and density functional calculations. NiPS_{3} displays an anomalous shift in the optical spectral weight at the magnetic ordering temperature, reflecting strong coupling between the electronic and magnetic structures. X-ray absorption, photoemission, and optical spectra support a self-doped ground state in NiPS_{3}. Our work demonstrates that layered transition-metal trichalcogenide magnets are useful candidates for the study of correlated-electron physics in two-dimensional magnetic materials.

10.
Nat Commun ; 8(1): 1702, 2017 11 17.
Artigo em Inglês | MEDLINE | ID: mdl-29150597

RESUMO

A correction to this article has been published and is linked from the HTML version of this article.

11.
Sci Rep ; 7(1): 10494, 2017 09 05.
Artigo em Inglês | MEDLINE | ID: mdl-28874789

RESUMO

We report on infrared spectroscopy experiments on the electronic response in (Sr1-x La x )2IrO4 (x = 0, 0.021, and 0.067). Our data show that electron doping induced by La substitution leads to an insulator-to-metal transition. The evolution of the electronic structure across the transition reveals the robustness of the strong electronic correlations against the electron doping. The conductivity data of the metallic compound show the signature of the pseudogap that bears close similarity to the analogous studies of the pseudogap in the underdoped cuprates. While the low energy conductivity of the metallic compound is barely frequency dependent, the formation of the pseudogap is revealed by the gradual suppression of the featureless conductivity below a threshold frequency of about 17 meV. The threshold structure develops below about 100 K which is in the vicinity of the onset of the short-range antiferromagnetic order. Our results demonstrate that the electronic correlations play a crucial role in the anomalous charge dynamics in the (Sr1-x La x )2IrO4 system.

12.
Nat Commun ; 8(1): 251, 2017 08 15.
Artigo em Inglês | MEDLINE | ID: mdl-28811471

RESUMO

5d pyrochlore oxides with all-in-all-out magnetic order are prime candidates for realizing strongly correlated, topological phases of matter. Despite significant effort, a full understanding of all-in-all-out magnetism remains elusive as the associated magnetic excitations have proven difficult to access with conventional techniques. Here we report a Raman spectroscopy study of spin dynamics in the all-in-all-out magnetic state of the 5d pyrochlore Cd2Os2O7. Through a comparison between the two-magnon scattering and spin-wave theory, we confirm the large single ion anisotropy in this material and show that the Dzyaloshinskii-Moriya and exchange interactions play a significant role in the spin-wave dispersions. The Raman data also reveal complex spin-charge-lattice coupling and indicate that the metal-insulator transition in Cd2Os2O7 is Lifshitz-type. Our work establishes Raman scattering as a simple and powerful method for exploring the spin dynamics in 5d pyrochlore magnets.Pyrochlore 5d transition metal oxides are expected to have interesting forms of magnetic order but are hard to study with conventional probes. Here the authors show that Raman scattering can be used to measure magnetic excitations in Cd2Os2O7 and that it exhibits complex spin-charge-lattice coupling.

13.
Phys Rev Lett ; 118(11): 117201, 2017 Mar 17.
Artigo em Inglês | MEDLINE | ID: mdl-28368646

RESUMO

Spin-phonon coupling mediated by single ion anisotropy was investigated using optical spectroscopy and first-principles calculations in the all-in-all-out pyrochlore magnet Cd_{2}Os_{2}O_{7}. Clear anomalies were observed in both the phonon frequencies and linewidths at the magnetic ordering temperature. The renormalization of the phonon modes was exceptionally large, signifying the presence of an unconventional magnetoelastic term from large spin-orbit coupling. In addition, the relative phonon frequency shifts show a strong correlation with the modulation of noncubic crystal field by the corresponding lattice distortion. Our observation establishes a new type of spin-phonon coupling through single ion anisotropy, a second-order spin-orbit coupling term, in Cd_{2}Os_{2}O_{7}.

14.
Phys Rev Lett ; 119(26): 267402, 2017 Dec 29.
Artigo em Inglês | MEDLINE | ID: mdl-29328701

RESUMO

The prototypical correlated metal Sr_{2}RhO_{4} was studied using optical and photoemission spectroscopy. At low energies and temperatures, the optical data reveal a complex, multicomponent response that on the surface points to an unconventional metallic state in this material. Via a comparison with photoemission, the anomalous optical response may be attributed to an unexpectedly strong interband transition near 180 meV between spin-orbit coupled bands that are nearly parallel along ΓX. This spin-orbit coupling effect is shown to occur in a number of related metallic ruthenates and explains the previously puzzling optical properties reported for these materials.

15.
Genet Mol Res ; 15(3)2016 Sep 02.
Artigo em Inglês | MEDLINE | ID: mdl-27706685

RESUMO

The slender shiner Pseudopungtungia tenuicorpa (Cypriniformes; Cyprinidae; Gobioninae) is an endangered freshwater fish species endemic to Korea. The current strategies for its conservation involve the study of population genetic characters and identification of management units. These strategies require suitable molecular markers to study genetic diversity and genetic structure. Here, we developed nine polymorphic microsatellite markers for P. tenuicorpa for the first time by applying an enrichment method from a size-selected genomic library. The developed microsatellite markers produced a total of 101 alleles (average 11.2). The observed and expected heterozygosities averaged 0.805 and 0.835, respectively. Among the nine identified markers, five markers showed successful amplification across five related Korean Gobioninae species. Thus, the microsatellite markers developed in this study will be useful to establish conservation strategies for both P. tenuicorpa and other related species.


Assuntos
Cyprinidae/genética , Genética Populacional , Repetições de Microssatélites , Alelos , Animais , Conservação dos Recursos Naturais , Cyprinidae/classificação , Espécies em Perigo de Extinção , Genoma , Biblioteca Genômica , Heterozigoto , Reação em Cadeia da Polimerase , República da Coreia , Especificidade da Espécie
16.
Sci Rep ; 6: 32632, 2016 09 07.
Artigo em Inglês | MEDLINE | ID: mdl-27599573

RESUMO

We report on infrared spectroscopic studies of the electronic response of the (Sr1-xLax)3Ir2O7 system. Our experiments revealed hallmarks of strong electronic correlations in the evolution of the electronic response across the filling-controlled insulator-metal transition. We observed a collapse of the Jeff = 1/2 Mott gap accompanying the transfer of the spectral weight from the high-energy region to the gap region with electron doping. The intraband conductivity at the metallic side of the transition was found to consist of coherent Drude-like and incoherent responses. The sum rule and the extended Drude model analyses further indicated a large mass enhancement. Our results demonstrate a critical role of the electronic correlations in the charge dynamics of the (Sr1-xLax)3Ir2O7 system.

17.
J Hand Surg Eur Vol ; 41(4): 448-52, 2016 May.
Artigo em Inglês | MEDLINE | ID: mdl-26329885

RESUMO

The aims of this study were to develop a classification for ring and little finger carpometacarpal joint fracture subluxations based on three-dimensional computed tomography images and evaluate the inter- and intraobserver reliability of the three-dimensional computed tomography classification. A retrospective review was performed of 30 cases of ring and little finger carpometacarpal joint fracture subluxations from 2005 to 2013. We classified ring and little finger carpometacarpal joint fracture subluxations into three types based on three-dimensional computed tomography images. An orthopaedic surgeon with 2 years of experience, a consultant hand surgeon with 8 years of experience, and a consultant radiologist with 9 years of experience, who were completely blind to the treatment algorithm, evaluated 30 cases twice at a 2-week interval using our new classification based on three-dimensional computed tomography images and the other classification based on two-dimensional computed tomography images. Our three-dimensional computed tomography classification showed almost perfect interobserver and intraobserver reliability and resulted in a better level of agreement than two-dimensional computed tomography classification.


Assuntos
Articulações Carpometacarpais/diagnóstico por imagem , Fratura-Luxação/classificação , Fratura-Luxação/diagnóstico por imagem , Fraturas Ósseas/classificação , Fraturas Ósseas/diagnóstico por imagem , Imageamento Tridimensional , Adolescente , Adulto , Idoso , Articulações Carpometacarpais/lesões , Humanos , Masculino , Pessoa de Meia-Idade , Variações Dependentes do Observador , Reprodutibilidade dos Testes , Estudos Retrospectivos , Tomografia Computadorizada por Raios X , Adulto Jovem
18.
J Phys Condens Matter ; 27(48): 485604, 2015 Dec 09.
Artigo em Inglês | MEDLINE | ID: mdl-26571347

RESUMO

We investigated temperature-dependent infrared-active phonon modes of honeycomb Li2MnO3 which shows an antiferromagnetic transition at T(N) = 36 K. In the far-infrared frequency region, we observed fourteen phonon modes. We obtained the temperature dependence of each phonon mode from the analysis of optical conductivity spectra by using the Lorentz and the Fano-type oscillator models. We found that the resonance frequencies of nine phonon modes showed an anomalous behavior near T(N) that should be attributed to the spin-phonon coupling. We calculated the magnitude of the spin-phonon coupling constant from the shift in the resonance frequencies of the phonon modes below T(N). Our results suggest that Li2MnO3 is weakly frustrated and that spin-phonon coupling plays a role in antiferromagnetic ordering.

19.
Osteoporos Int ; 26(4): 1387-94, 2015 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-25592134

RESUMO

UNLABELLED: We evaluated the correlation between central bone mineral density (BMD) and peripheral bone attenuation using lower extremity computed tomography (CT). A good correlation was found between lower extremity CT and central BMD suggesting that CT is useful for screening osteoporosis, and that peripheral bone attenuation adequately reflects central BMD. INTRODUCTION: This study aimed to evaluate the reliability and validity of CT as a screening tool for osteoporosis and to estimate the correlation between central BMD and peripheral bone attenuation using lower extremity CT. METHODS: In total, 292 patients who underwent a lower extremity, lumbar spine, or abdomen and pelvic CT scan within a 3-month interval of a dual-energy X-ray absorptiometry (DEXA) examination were included. Following reliability testing, bone attenuation of the L1, L2, L3, L4, femoral head, femoral neck, greater trochanter, distal femur, proximal tibia, distal tibia, and talus was measured by placing a circular region of interest on the central part of each bony region on a coronal CT image. Partial correlation was used to assess the correlation between CT and DEXA after adjusting for age and body mass index. RESULTS: In terms of reliability, all bone attenuation measurements, except the femoral neck, showed good to excellent interobserver reliability (intraclass correlation coefficients, 0.691-0.941). In terms of validity, bone attenuation of the L1 to L4, femoral neck, and greater trochanter on CT showed significant correlations with BMD of each area on DEXA (correlation coefficients, 0.399-0.613). Bone attenuation of the distal tibia and talus on CT showed significant correlations with BMD of all parts on DEXA (correlation coefficients, 0.493-0.581 for distal tibia, 0.396-0.579 for talus). CONCLUSION: Lower extremity CT is a useful screening tool for osteoporosis, and peripheral bone attenuation on lower extremity CT adequately reflects central BMD on DEXA.


Assuntos
Osteoporose/diagnóstico por imagem , Absorciometria de Fóton/métodos , Adulto , Idoso , Idoso de 80 Anos ou mais , Densidade Óssea , Feminino , Fêmur/diagnóstico por imagem , Fêmur/fisiopatologia , Humanos , Masculino , Programas de Rastreamento/métodos , Pessoa de Meia-Idade , Variações Dependentes do Observador , Osteoporose/fisiopatologia , Reprodutibilidade dos Testes , Estudos Retrospectivos , Tíbia/diagnóstico por imagem , Tíbia/fisiopatologia , Tomografia Computadorizada por Raios X/métodos
20.
Phys Rev Lett ; 115(26): 266402, 2015 Dec 31.
Artigo em Inglês | MEDLINE | ID: mdl-26765010

RESUMO

We investigated the metal-insulator transition (MIT) driven by all-in-all-out (AIAO) antiferromagnetic ordering in the 5d pyrochlore Cd(2)Os(2)O(7) using optical spectroscopy and first-principles calculations. We showed that the temperature evolution in the band-gap edge and free carrier density were consistent with rigid upward (downward) shifts of electron (hole) bands, similar to the case of Lifshitz transitions. The delicate relationship between the band gap and free carrier density provides experimental evidence for the presence of an AIAO metallic phase, a natural consequence of such MITs. The associated spectral weight change at high energy and first-principles calculations further support the origin of the MIT from the band shift near the Fermi level. Our data consistently support that the MIT induced by AIAO ordering in Cd(2)Os(2)O(7) is not close to a Slater type but instead to a Lifshitz type.

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