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1.
Nature ; 558(7708): 95-99, 2018 06.
Artigo em Inglês | MEDLINE | ID: mdl-29785052

RESUMO

The Peltier effect, discovered in 1834, converts a charge current into a heat current in a conductor, and its performance is described by the Peltier coefficient, which is defined as the ratio of the generated heat current to the applied charge current1,2. To exploit the Peltier effect for thermoelectric cooling or heating, junctions of two conductors with different Peltier coefficients have been believed to be indispensable. Here we challenge this conventional wisdom by demonstrating Peltier cooling and heating in a single material without junctions. This is realized through an anisotropic magneto-Peltier effect in which the Peltier coefficient depends on the angle between the directions of a charge current and magnetization in a ferromagnet. By using active thermography techniques3-10, we observe the temperature change induced by this effect in a plain nickel slab. We find that the thermoelectric properties of the ferromagnet can be redesigned simply by changing the configurations of the charge current and magnetization, for instance, by shaping the ferromagnet so that the current must flow around a curve. Our experimental results demonstrate the suitability of nickel for the anisotropic magneto-Peltier effect and the importance of spin-orbit interaction in its mechanism. The anisotropic magneto-Peltier effect observed here is the missing thermoelectric phenomenon in ferromagnetic materials-the Onsager reciprocal of the anisotropic magneto-Seebeck effect previously observed in ferromagnets-and its simplicity might prove useful in developing thermal management technologies for electronic and spintronic devices.

2.
Nature ; 560(7720): E36, 2018 08.
Artigo em Inglês | MEDLINE | ID: mdl-29907793

RESUMO

In this Letter, owing to an error during the production process, 'θH' was incorrectly written as 'θΗH' six times in the paragraph starting "Up to now,…". These errors have been corrected online.

3.
Plant Cell Physiol ; 64(4): 405-421, 2023 Apr 17.
Artigo em Inglês | MEDLINE | ID: mdl-36472361

RESUMO

Jasmonic acid (JA) regulates plant growth, development and stress responses. Coronatine insensitive 1 (COI1) and jasmonate zinc-finger inflorescence meristem-domain (JAZ) proteins form a receptor complex for jasmonoyl-l-isoleucine, a biologically active form of JA. Three COIs (OsCOI1a, OsCOI1b and OsCOI2) are encoded in the rice genome. In the present study, we generated mutants for each rice COI gene using genome editing to reveal the physiological functions of the three rice COIs. The oscoi2 mutants, but not the oscoi1a and oscoi1b mutants, exhibited severely low fertility, indicating the crucial role of OsCOI2 in rice fertility. Transcriptomic analysis revealed that the transcriptional changes after methyl jasmonate (MeJA) treatment were moderate in the leaves of oscoi2 mutants compared to those in the wild type or oscoi1a and oscoi1b mutants. MeJA-induced chlorophyll degradation and accumulation of antimicrobial secondary metabolites were suppressed in oscoi2 mutants. These results indicate that OsCOI2 plays a central role in JA response in rice leaves. In contrast, the assessment of growth inhibition upon exogenous application of JA to seedlings of each mutant revealed that rice COIs are redundantly involved in shoot growth, whereas OsCOI2 plays a primary role in root growth. In addition, a co-immunoprecipitation assay showed that OsJAZ2 and OsJAZ5 containing divergent Jas motifs physically interacted only with OsCOI2, whereas OsJAZ4 with a canonical Jas motif interacts with all three rice COIs. The present study demonstrated the functional diversity of rice COIs, thereby providing clues to the mechanisms regulating the various physiological functions of JA.


Assuntos
Proteínas de Arabidopsis , Arabidopsis , Oryza , Proteínas de Arabidopsis/metabolismo , Arabidopsis/genética , Oryza/genética , Oryza/metabolismo , Edição de Genes , Ciclopentanos/farmacologia , Ciclopentanos/metabolismo , Oxilipinas/farmacologia , Oxilipinas/metabolismo , Regulação da Expressão Gênica de Plantas
4.
Phys Rev Lett ; 131(20): 206701, 2023 Nov 17.
Artigo em Inglês | MEDLINE | ID: mdl-38039463

RESUMO

We report the observation of the anisotropic magneto-Thomson effect (AMTE), which is one of the higher-order thermoelectric effects in a ferromagnet. Using lock-in thermography, we demonstrated that in a ferromagnetic NiPt alloy, the cooling or heating induced by the Thomson effect depends on the angle between the magnetization direction and the temperature gradient or charge current applied to the alloy. AMTE observed here is the missing ferromagnetic analog of the magneto-Thomson effect in a nonmagnetic conductor, providing the basis for nonlinear spin caloritronics and thermoelectrics.

5.
Plant Mol Biol ; 109(4-5): 595-609, 2022 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-34822009

RESUMO

KEY MESSAGE: We show that in rice, the amino acid-conjugates of JA precursor, OPDA, may function as a non-canonical signal for the production of phytoalexins in coordination with the innate chitin signaling. The core oxylipins, jasmonic acid (JA) and JA-Ile, are well-known as potent regulators of plant defense against necrotrophic pathogens and/or herbivores. However, recent studies also suggest that other oxylipins, including 12-oxo-phytodienoic acid (OPDA), may contribute to plant defense. Here, we used a previously characterized metabolic defense marker, p-coumaroylputrescine (CoP), and fungal elicitor, chitooligosaccharide, to specifically test defense role of various oxylipins in rice (Oryza sativa). While fungal elicitor triggered a rapid production of JA, JA-Ile, and their precursor OPDA, rice cells exogenously treated with the compounds revealed that OPDA, rather than JA-Ile, can stimulate the CoP production. Next, reverse genetic approach and oxylipin-deficient rice mutant (hebiba) were used to uncouple oxylipins from other elicitor-triggered signals. It appeared that, without oxylipins, residual elicitor signaling had only a minimal effect but, in synergy with OPDA, exerted a strong stimulatory activity towards CoP production. Furthermore, as CoP levels were compromised in the OPDA-treated Osjar1 mutant cells impaired in the oxylipin-amino acid conjugation, putative OPDA-amino acid conjugates emerged as hypothetical regulators of CoP biosynthesis. Accordingly, we found several OPDA-amino acid conjugates in rice cells treated with exogenous OPDA, and OPDA-Asp was detected, although in small amounts, in the chitooligosaccharide-treated rice. However, as synthetic OPDA-Asp and OPDA-Ile, so far, failed to induce CoP in cells, it suggests that yet another presumed OPDA-amino acid form(s) could be acting as novel regulator(s) of phytoalexins in rice.


Assuntos
Oryza , Oxilipinas , Aminoácidos/metabolismo , Quitina/metabolismo , Quitosana , Ciclopentanos/metabolismo , Oligossacarídeos , Oryza/genética , Oxilipinas/metabolismo , Sesquiterpenos , Fitoalexinas
6.
Nat Mater ; 20(4): 463-467, 2021 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-33462463

RESUMO

When a temperature gradient is applied to a closed circuit comprising two different conductors, a charge current is generated via the Seebeck effect1. Here, we utilize the Seebeck-effect-induced charge current to drive 'transverse' thermoelectric generation, which has great potential for energy harvesting and heat sensing applications owing to the orthogonal geometry of the heat-to-charge-current conversion2-9. We found that, in a closed circuit comprising thermoelectric and magnetic materials, artificial hybridization of the Seebeck effect into the anomalous Hall effect10 enables transverse thermoelectric generation with a similar symmetry to the anomalous Nernst effect11-27. Surprisingly, the Seebeck-effect-driven transverse thermopower can be several orders of magnitude larger than the anomalous-Nernst-effect-driven thermopower, which is clearly demonstrated by our experiments using Co2MnGa/Si hybrid materials. The unconventional approach could be a breakthrough in developing applications of transverse thermoelectric generation.

7.
Ophthalmology ; 129(5): 488-497, 2022 05.
Artigo em Inglês | MEDLINE | ID: mdl-34890684

RESUMO

PURPOSE: To identify risk factors for further deterioration of central visual function in advanced glaucoma eyes. DESIGN: Prospective, observational 5-year study. PARTICIPANTS: Advanced glaucoma patients with well-controlled intraocular pressure (IOP), mean deviation (MD) of the Humphrey Field Analyzer (HFA) 24-2 program ≤-20 dB and best-corrected visual acuity (BCVA) of 20/40. METHODS: The HFA 10-2 test and BCVA examination were performed every 6 months, and the HFA 24-2 test was performed every 12 months for 5 years. The Cox proportional hazards model was used to identify risk factors for deterioration of HFA 10-2 and 24-2 results and BCVA. MAIN OUTCOME MEASURES: Deterioration of HFA 10-2 results was defined by the presence of the same ≥3 points with negative total deviation slope ≤-1 dB/year at P < 0.01 on ≥3 consecutive tests, deterioration of HFA 24-2 results by an increase ≥2 in the Advanced Glaucoma Intervention Study score on ≥2 consecutive tests, and deterioration of BCVA by an increase of ≥0.2 logarithm of the minimum angle of resolution (logMAR) on ≥2 consecutive tests. RESULTS: A total of 175 eyes of 175 patients (mean age, 64.1 years; mean baseline IOP, 13.2 mmHg; mean BCVA, 0.02 logMAR; mean HFA 24-2 and 10-2 MD, -25.9 and -22.9 dB, respectively) were included. The probabilities of deterioration in HFA 10-2 and 24-2 results and BCVA were 0.269 ± 0.043 (standard error), 0.173 ± 0.031, and 0.194 ± 0.033, respectively, at 5 years. Lower BCVA at baseline (P = 0.012) was associated significantly with further deterioration of HFA 10-2 results. Better HFA 24-2 MD (P < 0.001) and use of systemic antihypertensive agents (P = 0.009) were associated significantly with further deterioration of HFA 24-2 results, and a greater ß-peripapillary atrophy area-to-disc area ratio (P < 0.001), use of systemic antihypertensive agents (P = 0.025), and lower BCVA (P = 0.042) were associated significantly with further deterioration of BCVA, respectively. CONCLUSIONS: In advanced glaucoma eyes with well-controlled IOP, BCVA, ß-peripapillary atrophy area-to-disc area ratio, and use of systemic antihypertensive agents were significant prognostic factors for further deterioration of central visual function.


Assuntos
Glaucoma , Testes de Campo Visual , Anti-Hipertensivos/uso terapêutico , Atrofia , Glaucoma/diagnóstico , Glaucoma/tratamento farmacológico , Humanos , Pressão Intraocular , Pessoa de Meia-Idade , Estudos Prospectivos , Testes de Campo Visual/métodos , Campos Visuais
8.
Phys Rev Lett ; 128(4): 047601, 2022 Jan 28.
Artigo em Inglês | MEDLINE | ID: mdl-35148138

RESUMO

We formulate a scattering theory of polarization and heat transport through a ballistic ferroelectric point contact. We predict a polarization current under either an electric field or a temperature difference that depends strongly on the direction of the ferroelectric order and can be detected by its magnetic stray field and associated thermovoltage and Peltier effect.

9.
Sci Technol Adv Mater ; 23(1): 767-782, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-36386550

RESUMO

Transverse thermoelectric generation using magnetic materials is essential to develop active thermal engineering technologies, for which the improvements of not only the thermoelectric output but also applicability and versatility are required. In this study, using combinatorial material science and lock-in thermography technique, we have systematically investigated the transverse thermoelectric performance of Sm-Co-based alloy films. The high-throughput material investigation revealed the best Sm-Co-based alloys with the large anomalous Nernst effect (ANE) as well as the anomalous Ettingshausen effect (AEE). In addition to ANE/AEE, we discovered unique and superior material properties in these alloys: the amorphous structure, low thermal conductivity, and large in-plane coercivity and remanent magnetization. These properties make it advantageous over conventional materials to realize heat flux sensing applications based on ANE, as our Sm-Co-based films can generate thermoelectric output without an external magnetic field. Importantly, the amorphous nature enables the fabrication of these films on various substrates including flexible sheets, making the large-scale and low-cost manufacturing easier. Our demonstration will provide a pathway to develop flexible transverse thermoelectric devices for smart thermal management.

10.
Phys Rev Lett ; 126(18): 187603, 2021 May 07.
Artigo em Inglês | MEDLINE | ID: mdl-34018785

RESUMO

The spontaneous order of electric and magnetic dipoles in ferroelectrics and ferromagnets even at high temperatures is both fascinating and useful. Transport of magnetism in the form of spin currents is vigorously studied in spintronics, but the polarization current of the ferroelectric order has escaped attention. We therefore present a time-dependent diffusion theory for heat and polarization transport in a planar ferroelectric capacitor with parameters derived from a one-dimensional phonon model. We predict steady-state Seebeck and transient Peltier effects that await experimental discovery.

11.
Artigo em Inglês | MEDLINE | ID: mdl-33563879

RESUMO

The interconversion between spin, charge, and heat currents is being actively studied from the viewpoints of both fundamental physics and thermoelectric applications in the field of spin caloritronics. This field is a branch of spintronics, which has developed rapidly since the discovery of the thermo-spin conversion phenomenon called the spin Seebeck effect. In spin caloritronics, various thermo-spin conversion phenomena and principles have subsequently been discovered and magneto-thermoelectric effects, thermoelectric effects unique to magnetic materials, have received renewed attention with the advances in physical understanding and thermal/thermoelectric measurement techniques. However, the existence of various thermo-spin and magneto-thermoelectric conversion phenomena with similar names may confuse non-specialists. Thus, in this Review, the basic behaviors, spin-charge-heat current conversion symmetries, and functionalities of spin-caloritronic phenomena are summarized, which will help new entrants to learn fundamental physics, materials science, and application studies in spin caloritronics.


Assuntos
Temperatura Alta , Eletricidade , Fenômenos Magnéticos
12.
Sci Technol Adv Mater ; 22(1): 441-448, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34248419

RESUMO

For any thermoelectric effects to be achieved, a thermoelectric material must have hot and cold sides. Typically, the hot side can be easily obtained by excess heat. However, the passive cooling method is often limited to convective heat transfer to the surroundings. Since thermoelectric voltage is proportional to the temperature difference between the hot and cold sides, efficient passive cooling to increase the temperature gradient is of critical importance. Here, we report simultaneous harvesting of radiative cooling at the top and solar heating at the bottom to enhance the temperature gradient for a transverse thermoelectric effect which generates thermoelectric voltage perpendicular to the temperature gradient. We demonstrate this concept by using the spin Seebeck effect and confirm that the spin Seebeck device shows the highest thermoelectric voltage when both radiative cooling and solar heating are utilized. Furthermore, the device generates thermoelectric voltage even at night through radiative cooling which enables continuous energy harvesting throughout a day. Planar geometry and scalable fabrication process are advantageous for energy harvesting applications.

13.
Phys Rev Lett ; 125(10): 106601, 2020 Sep 04.
Artigo em Inglês | MEDLINE | ID: mdl-32955334

RESUMO

We report the observation of the higher-order thermoelectric conversion based on a magneto-Thomson effect. By means of thermoelectric imaging techniques, we directly observed the temperature change induced by the Thomson effect in a polycrystalline Bi_{88}Sb_{12} alloy under a magnetic field and found that the magnetically enhanced Thomson coefficient can be comparable to or even larger than the Seebeck coefficient. Our experiments reveal the significant contribution of the higher-order magnetothermoelectric conversion, opening the door to "nonlinear spin caloritronics."

14.
J Phys Ther Sci ; 32(3): 215-222, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-32184536

RESUMO

[Purpose] The purpose of this study was to examine the effectiveness of unsupervised low-intensity home exercises in improving physical activity and physical capacity for daily activities among the community-dwelling elderly. [Participants and Methods] We included 24 female older participants and divided them into two groups: 14 in the resistance training group and 10 in the fast walking group. The resistance training group performed shoulder joint flexion and abduction exercises using a resistance tube twice daily (in the morning and afternoon). Participants in the fast walking group walked fast for 3,000 steps once daily. Both groups continued the exercise intervention for 6 months. We measured the forced vital capacity, respiratory muscle strength, physical activity, walking distance in the 6-min walk test, grip strength, and knee extension strength before and after the intervention. [Results] The forced vital capacity significantly increased in the resistance training group, whereas the moderate-intensity physical activity time significantly increased in both groups and the vigorous-intensity physical activity time increased in the fast walking group only. We observed no intergroup differences in respiratory muscle strength, 6-min walking distance, grip strength, or knee extension strength. [Conclusion] The results of this study suggest that low-intensity home exercises can improve pulmonary function and physical activity and should be recommended for promoting health in the community-dwelling elderly.

15.
Biosci Biotechnol Biochem ; 83(5): 876-881, 2019 May.
Artigo em Inglês | MEDLINE | ID: mdl-30676297

RESUMO

A facile and efficient method has been developed for the optical resolution of racemic jasmonic acid (JA) on a relatively large scale and was successfully utilized for the preparation of optically pure (+)-JA and (-)-JA. We indicated that (+)-JA has lower growth inhibitory activity than (-)-JA in the rice seedling growth test and confirmed in line with an earlier observation that their respective biologically-active forms, (+)-JA-Ile and (-)-JA-Ile, show comparable inhibitory activities. We compared the metabolism of (+)-JA and (-)-JA into (+)-JA-Ile and (-)-JA-Ile, respectively, in the JA-deficient rice cpm2, and found that the exogenously applied (+)-JA was metabolized to the corresponding Ile conjugate less efficiently as compared with (-)-JA. Such metabolic rate difference may cause a discrepancy between biological potencies of (+)-JA and (-)-JA in rice. Abbreviations: FW: fresh weight; Ile: isoleucine; JA: jasmonic acid; JA-Ile: jasmonoyl-l-isoleucine; LC-ESI-MS/MS: liquid chromatography and electrospray ionization tandem mass spectrometry; MeJA: methyl jasmonate; OPDA: 12-oxophytodienoic acid.


Assuntos
Ciclopentanos/metabolismo , Oryza/metabolismo , Oxilipinas/metabolismo , Reguladores de Crescimento de Plantas/metabolismo , Espectroscopia de Ressonância Magnética Nuclear de Carbono-13 , Cromatografia Líquida , Ciclopentanos/química , Oryza/crescimento & desenvolvimento , Oxilipinas/química , Reguladores de Crescimento de Plantas/química , Espectroscopia de Prótons por Ressonância Magnética , Estereoisomerismo , Espectrometria de Massas em Tandem
16.
No Shinkei Geka ; 47(4): 419-427, 2019 Apr.
Artigo em Japonês | MEDLINE | ID: mdl-31061226

RESUMO

OBJECTIVE: Anterior condylar confluent dural arteriovenous fistula(ACC-dAVF)constitutes 3.7% of the total dAVF cases reported and has been regarded as a rare disease in the past. However, encounters with this disease are increasing due to MRI and awareness of this condition. The symptoms of this disease have been reported as tinnitus(75%), ocular symptoms(31%), sublingual nerve palsy(12%), spinal cord symptoms(11%), and intracranial bleeding(5%). Here, we report our identification of a case of ACC-dAVF, which is different from conventional reports, and the associated findings. CASE PRESENTATIONS: We experienced a series of 3 cases of ACC-dAVF with the chief complaint of neck pain. The symptoms in all three patients disappeared after transvenous embolization. Based on the pathophysiology of cervical pain, we presumed that the blood flow dynamics of the odontoid arcade was involved. As expected, after the blood flow near the transverse ligament of the atlas was normalized the symptoms disappeared. CONCLUSION: We could not find previous reports of ACC-dAVF where the main symptom was cervical pain. We report the possibility of a mechanism of dAVF different from those reported previously.


Assuntos
Malformações Vasculares do Sistema Nervoso Central , Embolização Terapêutica , Zumbido , Malformações Vasculares do Sistema Nervoso Central/complicações , Malformações Vasculares do Sistema Nervoso Central/diagnóstico por imagem , Malformações Vasculares do Sistema Nervoso Central/terapia , Humanos , Imageamento por Ressonância Magnética , Cervicalgia/etiologia , Zumbido/etiologia
17.
Nat Mater ; 21(2): 136-137, 2022 02.
Artigo em Inglês | MEDLINE | ID: mdl-35110741

Assuntos
Anisotropia
19.
Phys Rev Lett ; 117(20): 207203, 2016 Nov 11.
Artigo em Inglês | MEDLINE | ID: mdl-27886475

RESUMO

Sharp structures in the magnetic field-dependent spin Seebeck effect (SSE) voltages of Pt/Y_{3}Fe_{5}O_{12} at low temperatures are attributed to the magnon-phonon interaction. Experimental results are well reproduced by a Boltzmann theory that includes magnetoelastic coupling. The SSE anomalies coincide with magnetic fields tuned to the threshold of magnon-polaron formation. The effect gives insight into the relative quality of the lattice and magnetization dynamics.

20.
Adv Sci (Weinh) ; 11(18): e2308543, 2024 May.
Artigo em Inglês | MEDLINE | ID: mdl-38447187

RESUMO

Transverse thermoelectric generation converts temperature gradient in one direction into an electric field perpendicular to that direction and is expected to be a promising alternative in creating simple-structured thermoelectric modules that can avoid the challenging problems facing traditional Seebeck-effect-based modules. Recently, large transverse thermopower has been observed in closed circuits consisting of magnetic and thermoelectric materials, called the Seebeck-driven transverse magneto-thermoelectric generation (STTG). However, the closed-circuit structure complicates its broad applications. Here, STTG is realized in the simplest way to combine magnetic and thermoelectric materials, namely, by stacking a magnetic layer and a thermoelectric layer together to form a bilayer. The transverse thermopower is predicted to vary with changing layer thicknesses and peaks at a much larger value under an optimal thickness ratio. This behavior is verified in the experiment, through a series of samples prepared by depositing Fe-Ga alloy thin films of various thicknesses onto n-type Si substrates. The measured transverse thermopower reaches 15.2 ± 0.4 µV K-1, which is a fivefold increase from that of Fe-Ga alloy and much larger than the current room temperature record observed in Weyl semimetal Co2MnGa. The findings highlight the potential of combining magnetic and thermoelectric materials for transverse thermoelectric applications.

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