Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 12 de 12
Filtrar
1.
J Am Chem Soc ; 146(1): 201-209, 2024 Jan 10.
Artigo em Inglês | MEDLINE | ID: mdl-38134356

RESUMO

Light, a nondestructive and remotely controllable external stimulus, effectively triggers a variety of electron-transfer phenomena in metal complexes. One prime example includes using light in molecular cyanide-bridged [FeCo] bimetallic Prussian blue analogues, where it switches the system between the electron-transferred metastable state and the system's ground state. If this process is coupled to a ferroelectric-type phase transition, the generation and disappearance of macroscopic polarization, entirely under light control, become possible. In this research, we successfully executed a nonpolar-to-polar phase transition in a trinuclear cyanide-bridged [Fe2Co] complex crystal via directional electron transfer. Intriguingly, by exposing the crystal to the wavelength of light─785 nm─without any electric field─we can drive this ferroelectric phase transition to completely depolarize the crystal, during which a measurable electric current response can be detected. These discoveries signify an important step toward the realization of fully light-controlled ferroelectric memory devices.

2.
Angew Chem Int Ed Engl ; : e202409948, 2024 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-38949953

RESUMO

As a remote and non-contact stimulus, light offers the potential for manipulating the polarization of ferroelectric materials without physical contact. However, in current research, the non-contact write-read (erase) process lacks direct observation through the stable current as output signal. To address this limitation, we investigated the photoinduced polarization switching capabilities of the cyanide-bridged compound [Fe2Co] using visible light, leading to the achievement of rewritable polarization. By subjecting [Fe2Co] crystals to alternating irradiation with 785 nm and 532 nm light, the polarization changes exhibited a distinct square wave pattern, confirming the reliability of the writing and erasing processes. Initialization involved exposing specific crystal units to 532 nm light for storing "1" or "0" information, while reading was accomplished by scanning the units with 785 nm light, resulting in brief current pulses for "1" states and no current signal for "0" states. This research unveils new possibilities for optical storage systems, paving the way for efficient and rewritable data storage and retrieval technologies, such as the next-generation memories.

3.
J Am Chem Soc ; 145(29): 15647-15651, 2023 Jul 26.
Artigo em Inglês | MEDLINE | ID: mdl-37462373

RESUMO

Molecular-based magnetoelectric materials are among the most promising materials for next-generation magnetoelectric memory devices. However, practical application of existing molecular systems has proven difficult largely because the polarization change is far lower than the practical threshold of the ME memory devices. Herein, we successfully obtained an [FeCo] dinuclear complex that exhibits a magnetic field-induced spin crossover process, resulting in a significant polarization change of 0.45 µC cm-2. Mössbauer spectroscopy and theoretical calculations suggest that the asymmetric structural change, coupled with electron redistribution, leads to the observed polarization change. Our approach provides a new strategy toward rationally enhancing the polarization change.

4.
Angew Chem Int Ed Engl ; 61(39): e202208771, 2022 Sep 26.
Artigo em Inglês | MEDLINE | ID: mdl-35906869

RESUMO

Using light as a local heat source to induce a temporary pyroelectric current is widely recognized as an effective way to control the polarization of crystalline materials. In contrast, harnessing light directly to modulate the polarization of a crystal via excitation of the electronic bands remains less explored. In this study, we report an FeII spin crossover crystal that exhibits photoinduced macroscopic polarization change upon excitation by green light. When the excited crystal relaxes to the ground state, the corresponding pyroelectric current can be detected. An analysis of the structures, magnetic properties and the Mössbauer and infrared spectra of the complex, supported by calculations, revealed that the polarization change is dictated by the directional relative movement of ions during the spin transition process. The spin transition and polarization change occur simultaneously in response to light stimulus, which demonstrates the enormous potential of polar spin crossover systems in the field of optoelectronic materials.

5.
Dalton Trans ; 53(6): 2512-2516, 2024 Feb 06.
Artigo em Inglês | MEDLINE | ID: mdl-38224229

RESUMO

Light-induced polarization switchable molecular materials have attracted attention for decades owing to their potential remote manipulation and ultrafast responsiveness. Here we report a valence tautomeric (VT) complex with an enantiopure chiral ligand. By a suitable choice of counter anions, a significant improvement in photoconversion has been demonstrated, leading to novel photo-responsive polarization switching materials.

6.
Zhongguo Gu Shang ; 36(6): 519-24, 2023 Jun 25.
Artigo em Zh | MEDLINE | ID: mdl-37366093

RESUMO

OBJECTIVE: To observe the analgesic effect of Tuina by pressing and kneading the Huantiao (GB30) acupoint on rats with chronic constriction injury (CCI) and to explore the analgesic mechanism of Tuina on sciatica rats. METHODS: Thirty-two SPF male SD rats weighing 180 to 220 g were randomly divided into fore groups:blank group (without any treatment), sham group (only exposed without sciatic nerve ligating), model group (sciatic nerve ligating) and Tuina group (manual intervention after lsciatic nerve ligating). The CCI model was prepared by ligating the right sciatic nerve of the rats, on the third day of modeling, the rats in the Tuina group were given pressing and kneading the Huantiao (GB30) point for 14 days, and the changes of paw withdrawal threshold(PWT), paw withdrawal latency(PWL) were measured before and on the 1st, 3rd, 7th, 10th, 14th and 17th days after modeling. The changes of sciatic functional index(SFI) were measured before and on the 1st and 17th day after modeling. The morphological changes of the sciatic nerve were observed by hematoxylin-eosin(HE) staining;and the differences in NF-κB protein expression in the right dorsal horn of the spinal cord of rats were detected. RESULTS: Following modeling, there was no significant difference in PWT, PWL and SFI between the blank group and the sham group (P>0.05), but the PWT, PWL and SFI of the model group and the Tuina group decreased significantly (P<0.01). After manual intervention, the pain threshold of rats in Tuina group increased. On the 8th day of manual intervention (the 10th day after modeling), PWT in Tuina group increased significantly compared with that in model group (P<0.01). On the 5th day of manual intervention (the 7th day after modeling), the PWL of the massage group was significantly higher than that of the model group (P<0.01). The pain threshold of rats in Tuina group continued to rise with the continuous manipulation intervention. After 14 days of manipulative intervention, the sciatic nerve function index of rats in the Tuina group increased significantly(P<0.01). Compared with the blank group and sham group, the myelinated nerve fibers of sciatic nerve in the model group were disordered and the density of axons and myelin sheath was uneven. Compared with the model group, the nerve fibers of rats in the Tuina group were gradually continuous and the axons and myelin sheath were more uniform than those in the model group. Compared with the blank group and sham group, the expression of NF-κB protein in the right spinal dorsal horn of the model group was significantly increased(P<0.01). Compared with the model group, the expression of NF-κB protein in the right spinal dorsal horn of rats in Tuina group decreased significantly(P<0.01). CONCLUSION: Pressing and kneading the Huantiao (GB30) point restores nerve fiber alignment;and improves the PWT、PWL and SFI in the CCI model by decreasing NF-κB p65 protein expression in the spinal dorsal horn. There fore, Tuina demmstrates an analgesic effect and improves the gait of rats with sciatica.


Assuntos
Ciática , Ratos , Masculino , Animais , Ratos Sprague-Dawley , Ciática/terapia , NF-kappa B/metabolismo , Pontos de Acupuntura , Corno Dorsal da Medula Espinal/metabolismo , Medula Espinal , Massagem
7.
Psychiatry Res Neuroimaging ; 334: 111674, 2023 09.
Artigo em Inglês | MEDLINE | ID: mdl-37413860

RESUMO

INTRODUCTION: Lumbar disk herniation (LDH) is the preeminent disease of lever positioning manipulation (LPM), a complex disorder involving alterations in brain function. Resting-state functional magnetic resonance imaging (rs-fMRI) has the advantages of non-trauma, zero radiation, and high spatial resolution, which has become an effective means to study brain science in contemporary physical therapy. Furthermore, it can better elucidate the response characteristics of the brain region of LPM intervention in LDH. We utilized two data analysis methods, the amplitude of low-frequency fluctuation (ALFF) and regional homogeneity (ReHo) of rs-fMRI, to assess the effects of LPM on real-time brain activity in patients with LDH. METHODS: Patients with LDH (Group 1, n = 21) and age-, gender- and education-matched healthy controls without LDH (Group 2, n = 21) were prospectively enrolled. Brain fMRI was performed for Group 1 at two-time points (TPs): before LPM (TP1) and after one LPM session (TP2). The healthy controls (Group 2) did not receive LPM and underwent only one fMRI scan. Participants in Group 1 completed clinical questionnaires assessing pain and functional disorders using a Visual Analog Scale and the Japanese Orthopaedic Association (JOA), respectively. Furthermore, we employed MNL90 (Montreal Neurological Institute) as a brain-specific template. RESULTS: Compared to the healthy controls (Group 2), the patients with LDH (Group 1) had significant variation in ALFF and ReHo values in brain activity. After the LPM session (TP2), Group 1 at TP1 also showed significant variation in ALFF and ReHo values in brain activity. In addition, the latter (TP2 vs TP1) showed more significant changes in brain regions than the former (Group 1 vs Group 2). The ALFF values were increased in the Frontal_Mid_R and decreased in the Precentral_L in Group 1 at TP2 compared with TP1. The Reho values were increased in the Frontal_Mid_R and decreased in the Precentral_L in Group 1 at TP2 compared with TP1. The ALFF values were increased in the Precuneus_R and decreased in the Frontal_Mid_Orb_L in Group 1 compared with Group 2. Only three brain areas with significant activity in Group 1 compared with Group 2: Frontal_Mid_Orb_L, Frontal_Sup_Orb_L, and Frontal_Mid_R. ALFF value in the Frontal_Mid_R at TP2 correlated positively with the change rates of JOA scores between TP1 and TP2 (P = 0.04, r = 0.319, R2 = 0.102). DISCUSSION: Patients with LDH showed abnormal brain ALFF and ReHo values, which were altered after LPM. The default mode network, prefrontal cortex, and primary somatosensory cortex regions could predict real-time brain activity for sensory and emotional pain management in patients with LDH after LPM.


Assuntos
Mapeamento Encefálico , Deslocamento do Disco Intervertebral , Humanos , Mapeamento Encefálico/métodos , Deslocamento do Disco Intervertebral/diagnóstico por imagem , Deslocamento do Disco Intervertebral/terapia , Encéfalo/diagnóstico por imagem , Imageamento por Ressonância Magnética/métodos , Córtex Pré-Frontal
8.
J Pain Res ; 16: 2115-2129, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37361428

RESUMO

Background: Research on the brain mechanisms underlying manual therapy (MT)-induced analgesia has been conducted worldwide. However, no bibliometric analysis has been performed on functional magnetic resonance imaging (fMRI) studies of MT analgesia. To provide a theoretical foundation for the practical application of MT analgesia, this study examined the current incarnation, hotspots, and frontiers of fMRI-based MT analgesia research over the previous 20 years. Methods: All publications were obtained from the Science Citation Index-Expanded (SCI-E) of Web of Science Core Collection (WOSCC). We used CiteSpace 6.1.R3 to analyze publications, authors, cited authors, countries, institutions, cited journals, references, and keywords. We also evaluated keyword co-occurrences and timelines, and citation bursts. The search was conducted from 2002-2022 and was completed within one day on October 7, 2022. Results: In total, 261 articles were retrieved. The total number of annual publications showed a fluctuating but overall increasing trend. Author B. Humphreys had the highest number of publications (eight articles) and J. E. Bialosky had the highest centrality (0.45). The United States of America (USA) was the country with the most publications (84 articles), accounting for 32.18% of all publications. Output institutions were mainly the University of Zurich, University of Switzerland, and the National University of Health Sciences of the USA. The Spine (118) and the Journal of Manipulative and Physiological Therapeutics (80) were most frequently cited. The four hot topics in fMRI studies on MT analgesia were "low back pain", "magnetic resonance imaging", "spinal manipulation", and "manual therapy." The frontier topics were "clinical impacts of pain disorders" and "cutting-edge technical capabilities offered by magnetic resonance imaging". Conclusion: fMRI studies of MT analgesia have potential applications. fMRI studies of MT analgesia have linked several brain areas, with the default mode network (DMN) garnering the most attention. Future research should include international collaboration and RCTs on this topic.

9.
Zhongguo Gu Shang ; 35(2): 132-5, 2022 Feb 25.
Artigo em Zh | MEDLINE | ID: mdl-35191264

RESUMO

OBJECTIVE: To investigate the correlation between the changes of cervical curvature and atlantoaxial instability. METHODS: The correlation between the changes of cervical curvature and atlantoaxial instability was retrospectively studied in 50 outpatients with abnormal cervical curvature (abnormal cervical curvature group) from January 2018 to December 2019. There were 24 males and 26 females in abnormal cervical curvature group, aged from 18 to 42 years old with an average of(30.62±5.83) years. And 53 patients with normal cervical curvature (normal cervical curvature group) during the same period were matched, including 23 males and 30 females, aged from 21 to 44 years with an average of(31.98±6.11) years. Cervical spine X-ray films of 103 patients were taken in lateral position and open mouth position. Cervical curvature and variance of bilateral lateral atlanto-dental space(VBLADS) were measured and recorded, Pearson correlation coefficient analysis was used to study the correlation between the changes of cervical curvature and atlantoaxial instability. RESULTS: Atlantoaxial joint instability accounted for 39.6%(21/53) in normal cervical curvature group and 84.0%(42/50) in abnormal cervical curvature group. There was significant difference between two groups(P<0.01). VBLADS in abnormal cervical curvature group was (1.79±1.01) mm, which was significantly higher than that in normal cervical curvature group(0.55±0.75) mm(P<0.01). Pearson correlation coefficient analysis showed that the size of cervical curvature was negatively correlated with VBLADS. CONCLUSION: Cervical curvature straightening and inverse arch are the cause of atlantoaxial instability, the smaller the cervical curvature, the more serious the atlantoaxial instability.


Assuntos
Articulação Atlantoaxial , Instabilidade Articular , Cifose , Adolescente , Adulto , Articulação Atlantoaxial/diagnóstico por imagem , Vértebras Cervicais/diagnóstico por imagem , Feminino , Humanos , Instabilidade Articular/diagnóstico por imagem , Masculino , Radiografia , Estudos Retrospectivos , Adulto Jovem
10.
Artigo em Zh | MEDLINE | ID: mdl-24579464

RESUMO

OBJECTIVE: To explore the levels of serum GP73 in patients with fatty liver disease. METHODS: The sera GP73 were determined by ELISA in 178 patients with fatty liver disease and 100 healthy controls. RESULTS: Serum GP73 levels were significantly increased in patients with various fatty liver diseases(70.62 +/- 60.60 ng/ml), compared with those of control population (35.61 +/- 12.22 ng/ml). In patients with alcoholic fatty liver disease, acute liver injury, chronic hepatitis B, and non-alcoholic fatty liver disease, their serum GP73 concentration were 81.86 +/- 47.82 ng/ml, 82.77 +/- 77.73 ng/ml, 63.84 +/- 50.62 ng/ml, and 65.75 +/- 62.20 ng/ml, respectively. But no significant difference was found between these groups (P > 0.05). In 68 patients with F > or = 1.0 (71.46 +/- 66.48 ng/ml), 75 patients with F> or = 2.0 (69.58 +/- 62.31 ng/ml), and 34 patients with F3-F4 (71.65 +/- 43.89 ng/ml), there were also no marked differences was observed between these fatty groups (F = 0.02, P = 0.98). CONCLUSION: Serum GP73 levels were increased in patients with different liver diseases, but its concentrations were seems not related with degree of fatty injury.


Assuntos
Fígado Gorduroso/sangue , Proteínas de Membrana/sangue , Adolescente , Adulto , Idoso , Criança , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Adulto Jovem
SELEÇÃO DE REFERÊNCIAS
Detalhe da pesquisa