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1.
Sci Bull (Beijing) ; 2024 Apr 26.
Artigo em Inglês | MEDLINE | ID: mdl-38762435

RESUMO

Quantum Hall effect, the quantized transport phenomenon of electrons under strong magnetic fields, remains one of the hottest research topics in condensed matter physics since its discovery in 2D electronic systems. Recently, as a great advance in the research of quantum Hall effects, the quantum Hall effect in 3D systems, despite its big challenge, has been achieved in the bulk ZrTe5 and Cd3As2 materials. Interestingly, Cd3As2 is a Weyl semimetal, and quantum Hall effect is hosted by the Fermi arc states on opposite surfaces via the Weyl nodes of the bulk, and induced by the unique edge states on the boundaries of the opposite surfaces. However, such intriguing edge state distribution has not yet been experimentally observed. Here, we aim to reveal experimentally the unusual edge states of Fermi arcs in acoustic Weyl system with the aid of pseudo-magnetic field. Benefiting from the macroscopic nature of acoustic crystals, the pseudo-magnetic field is introduced by elaborately designed the gradient on-site energy, and the edge states of Fermi arcs on the boundaries of the opposite surfaces are unambiguously demonstrated in experiments. Our system serves as an ideal and highly tunable platform to explore the Hall physics in 3D system, and has the potential in the application of new acoustic devices.

2.
Nat Commun ; 15(1): 1798, 2024 Feb 27.
Artigo em Inglês | MEDLINE | ID: mdl-38413597

RESUMO

Continuum Landau modes - predicted recently in a non-Hermitian Dirac Hamiltonian under a uniform magnetic field - are continuous bound states with no counterparts in Hermitian systems. However, they have still not been confirmed in experiments. Here, we report an experimental observation of continuum Landau modes in non-Hermitian electric circuits, in which the non-Hermitian Dirac Hamiltonian is simulated by non-reciprocal hoppings and the pseudomagnetic field is introduced by inhomogeneous complex on-site potentials. Through measuring the admittance spectrum and the eigenstates, we successfully verify key features of continuum Landau modes. Particularly, we observe the exotic voltage response acting as a rainbow trap or wave funnel through full-field excitation. This response originates from the linear relationship between the modes' center position and complex eigenvalues. Our work builds a bridge between non-Hermiticity and magnetic fields, and thus opens an avenue to explore exotic non-Hermitian physics.

3.
Phys Rev Lett ; 130(26): 266304, 2023 Jun 30.
Artigo em Inglês | MEDLINE | ID: mdl-37450801

RESUMO

Chiral anomaly as the hallmark feature lies in the heart of the researches for Weyl semimetal. It is rooted in the zeroth Landau level of the system with an applied magnetic field. Chirality or antichirality characterizes the propagation property of the one-way zeroth Landau level mode, and antichirality means an opposite group velocity compared to the case of chirality. Chirality is commonly observed for Weyl semimetals. Interestingly, the type-II Weyl point, with the overtilted dispersion, may flip the chirality to the antichirality, which, however, is yet to be evidenced despite numerous previous experimental efforts. Here, we implement the type-II Weyl point in sonic crystals, and by creating the pseudomagnetic fields with geometric deformation, the chirality flip of zeroth Landau levels is unambiguously demonstrated. Our Letter unveils the novel antichiral transport in the presence of time-reversal symmetry, and paves the way toward the state-of-the-art manipulation of sound waves.


Assuntos
Coração , Campos Magnéticos , Reprodução
4.
Artigo em Chinês | WPRIM (Pacífico Ocidental) | ID: wpr-969979

RESUMO

OBJECTIVE@#To observe the clinical effect of acupuncture for delayed sleep-wake phase disorder (DSWPD).@*METHODS@#A total of 84 patients with DSWPD were randomized into an observation group (42 cases, 2 cases dropped off) and a control group (42 cases, 3 cases dropped off). On the basis of sleep hygiene education, acupuncture was applied at Shenmai (BL 62), Zhaohai (KI 6), Hegu (LI 4), Taichong (LR 3), Zusanli (ST 36) and Sanyinjiao (SP 6) in the observation group, while placebo acupuncture was applied at the same acupoints in the control group. The treatment lasted for 8 weeks, once every other day, 3 times a week in the 1st to 4th weeks; once every 3 days, 2 times a week in the 5th to 8th weeks. Before and after treatment, the actigraphy (ACT) indexes of objective sleep (total time of stay in bed, total sleep time, sleep efficiency, the number of awakenings and the wake time after falling asleep) and plasma cortisol (CORT) level were observed; before and after treatment and in follow-up of 1, 3 months after treatment, the scores of morningness-eveningness questionnaire (MEQ), insomnia severity index (ISI), fatigue severity scale (FSS) and Epworth sleepiness scale (ESS) were observed in the two groups.@*RESULTS@#Compared before treatment, the total sleep time was prolonged, the sleep efficiency was improved, the number of awakenings was reduced, and the wake time after falling asleep was shortened after treatment in the observation group (P<0.01, P<0.05), and those in the observation group after treatment were superior to the control group (P<0.01, P<0.05). Compared before treatment, the MEQ scores after treatment in both groups and in the follow-up of 1, 3 months after treatment in the observation group were increased (P<0.01), and the MEQ score of each time point after treatment in the observation group was higher than the control group (P<0.01). The scores of ISI, FSS and ESS after treatment, and the scores of ISI、ESS in follow-up of 1, 3 months after treatment in the observation group were decreased compared with those before treatment (P<0.01, P<0.05), and in the observation group, the scores of ISI, FSS and ESS of each time point after treatment were lower than those in the control group (P<0.01, P<0.05). After treatment, the plasma CORT level in the observation group was decreased compared with that before treatment and that in the control group (P<0.01, P<0.05).@*CONCLUSION@#Acupuncture can improve the sleep and wake phase of patients with DSWPD, improve sleep quality and daytime function, and its mechanism may be related to the down-regulation of plasma CORT level.


Assuntos
Humanos , Terapia por Acupuntura , Sono , Pontos de Acupuntura , Regulação para Baixo , Duração do Sono
5.
Chinese Pharmacological Bulletin ; (12): 193-199, 2023.
Artigo em Chinês | WPRIM (Pacífico Ocidental) | ID: wpr-1013896

RESUMO

Aim To study the therapeutic effect of Balanophora polysaccharide(BPS)on gastric ulcer(GU)induced by acetic acid in rats and to investigateits mechanisms. Methods Sixty male SD rats were randomly divided into sham-operated group, GU model group, omeprazole positive group(3.6 mg·kg-1), and low, medium and high dose of BPS treatment groups(100, 200 and 400 mg·kg-1). The GU model group was prepared by acetic acid cautery method, and the morphology and pathological changes of ulcers were observed by visual observation combined with HE staining, and the ulcer area and inhibition rate were measured and calculated; superoxide dismutase(SOD)activity, malondialdehyde(MDA)content and glutathione peroxidase(GSH-PX)activity were measured by enzymatic assay; tumor necrosis factor-α(TNF-α)and interleukin-6(IL-6)content were detected by ELISA. The expression levels of epidermal growth factor(EGF)and epidermal growth factor receptor(EGFR)were measured by immunohistochemistry staining and Western blot. Results Compared with the sham-operated group, obvious ulcer damage was seen in the model group. Compared with the model group, the BPS-treated group showed a significant reduction in ulcer area, an increase in SOD and GSH-PX activity and EGF and EGFR expression levels, and a significant decrease in MDA, TNF-α and IL-6 content. Conclusions BPS has a therapeutic effect on GU in rats, and its mechanism may be related to the inhibition of oxidative stress, suppression of inflammatory stimuli and promotion of regenerative repair of gastric mucosa.

6.
Sci Bull (Beijing) ; 67(5): 488-494, 2022 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-36546169

RESUMO

Higher-order topological insulators (HOTIs), with topological corner or hinge states, have emerged as a thriving topic in the field of topological physics. However, few connections have been found for HOTIs with well-explored first-order topological insulators. Recently a proposal asserted that a significant bridge can be established between the HOTIs and Z2 topological insulators. When subjected to an in-plane Zeeman field, corner states, the signature of the HOTIs, can be induced in a Z2 topological insulator. Such Zeeman fields can be produced, for example, by the ferromagnetic proximity effect or magnetic atom doping, which drastically increases the experimental complexity. Here, we show that a phononic crystal, designed as a bilayer of coupled acoustic cavities, exactly hosts the Kane-Mele model with built-in in-plane Zeeman fields. The helical edge states along the zigzag edges are gapped, and the corner states, localized spatially at the corners of the samples, appear in the gap. This verifies the Zeeman field induced higher-order topology. We further demonstrate the intriguing contrast properties of the corner states at the outer and inner corners in a hexagonal ring-shaped sample.

7.
Phys Rev Lett ; 127(13): 136401, 2021 Sep 24.
Artigo em Inglês | MEDLINE | ID: mdl-34623863

RESUMO

The physical realization of pseudomagnetic fields (PMFs) is an engaging frontier of research. As in graphene, elastic PMF can be realized by the structural modulations of Dirac materials. We show that, in the presence of PMFs, the conical dispersions split into elastic Landau levels, and the elastic modes robustly propagate along the edges, similar to the quantum Hall edge transports. In particular, we reveal unique elastic snake states in an on-chip heterostructure with two opposite PMFs. The flexibility in the micromanufacture of silicon chips and the low loss of elastic waves provide an unprecedented opportunity to demonstrate various fascinating topological transports of the edge states under PMFs. These properties open new possibilities for designing functional elastic wave devices in miniature and compact scales.

8.
Phys Rev Lett ; 126(15): 156801, 2021 Apr 16.
Artigo em Inglês | MEDLINE | ID: mdl-33929222

RESUMO

Topological phases, including the conventional first-order and higher-order topological insulators and semimetals, have emerged as a thriving topic in the fields of condensed-matter physics and materials science. Usually, a topological insulator is characterized by a fixed order topological invariant and exhibits associated bulk-boundary correspondence. Here, we realize a new type of topological insulator in a bilayer phononic crystal, which hosts simultaneously the first-order and second-order topologies, referred to here as the hybrid-order topological insulator. The one-dimensional gapless helical edge states, and zero-dimensional corner states coexist in the same system. The new hybrid-order topological phase may produce novel applications in topological acoustic devices.

9.
Nat Mater ; 20(6): 812-817, 2021 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-33589800

RESUMO

The notion of higher-order topological insulators has endowed materials with topological states beyond the first order. Particularly, a three-dimensional (3D) higher-order topological insulator can host topologically protected 1D hinge states, referred to as the second-order topological insulator, or 0D corner states, referred to as the third-order topological insulator. Similarly, a 3D higher-order topological semimetal can be envisaged if it hosts states on the 1D hinges. Here we report the realization of a second-order topological Weyl semimetal in a 3D-printed acoustic crystal, which possesses Weyl points in 3D momentum space, 2D Fermi arc states on surfaces and 1D gapless states on hinges. Like the arc surface states, the hinge states also connect the projections of the Weyl points. Our experimental results evidence the existence of the higher-order topological semimetal, which may pave the way towards innovative acoustic devices.

10.
Phys Rev Lett ; 127(25): 255501, 2021 Dec 17.
Artigo em Inglês | MEDLINE | ID: mdl-35029433

RESUMO

The discovery of topologically protected boundary states in topological insulators opens a new avenue toward exploring novel transport phenomena. The one-way feature of boundary states against disorders and impurities prospects great potential in applications of electronic and classical wave devices. Particularly, for the 3D higher-order topological insulators, it can host hinge states, which allow the energy to transport along the hinge channels. However, the hinge states have only been observed along a single hinge, and a natural question arises: whether the hinge states can exist simultaneously on all the three independent directions of one sample? Here we theoretically predict, numerically simulate, and experimentally observe the hinge states on three different directions of a higher-order topological phononic crystal, and demonstrate their robust one-way transport from hinge to hinge. Therefore, 3D topological hinge transport is successfully achieved. The novel sound transport may serve as the basis for acoustic devices of unconventional functions.

11.
Sci Bull (Beijing) ; 66(19): 1959-1966, 2021 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-36654165

RESUMO

Metamaterials with higher-order topological band gaps that exhibit topological physics beyond the bulk-edge correspondence provide unique application values due to their ability of integrating topological boundary states at multiple dimensions in a single chip. On the other hand, in the past decade, micromechanical metamaterials are developing rapidly for various applications such as micro-piezoelectric-generators, intelligent micro-systems, on-chip sensing and self-powered micro-systems. To empower these cutting-edge applications with topological manipulations of elastic waves, higher-order topological mechanical systems working at high frequencies (MHz) with high quality-factors are demanded. The current realizations of higher-order topological mechanical systems, however, are still limited to systems with large scales (centimetres) and low frequencies (kHz). Here, we report the first experimental realization of an on-chip micromechanical metamaterial as the higher-order topological insulator for elastic waves at MHz. The higher-order topological phononic band gap is induced by the band inversion at the Brillouin zone corner which is achieved by configuring the orientations of the elliptic pillars etched on the silicon chip. With consistent experiments, theory and simulations, we demonstrate the emergence of coexisting topological edge and corner states in a single silicon chip as induced by the higher-order band topology. The experimental realization of on-chip micromechanical metamaterials with higher-order topology opens a new regime for materials and applications based on topological elastic waves.

12.
Artigo em Chinês | WPRIM (Pacífico Ocidental) | ID: wpr-878965

RESUMO

To systematically evaluate the clinical efficacy and safety of Lianhua Qingwen in the treatment of adult pneumonia. The randomized controlled trial of Lianhua Qingwen combined with conventional Western medicine in the treatment of pneumonia were retrieved from PubMed, EMbase, Wanfang database, VIP database, and CNKI from the establishment of database to March 2020. Two researchers independently conducted literature screening and data extraction, and the third researcher was in charge of arbitration in case of any disagreement. Outcome indicators included total clinical effective rate, symptom improvement time, and incidence of adverse events. R 3.6.1 was used for Meta-analysis, and RevMan 5.3 was used for quality evaluation. Twenty-two studies were included, with a total of 2 007 patients, including 1 017 patients in the experimental group and 990 patients in the control group. The results showed that the total clinical effective rate of the experimental group was higher than that of the control group(RR=1.11, 95%CI[1.08, 1.15], P<0.001), and the antifebrile time(MD=-1.81, 95%CI[-2.42,-1.21], P<0.001), cough duration(MD=-2.32, 95%CI[-2.89,-1.76], P<0.001), rale duration(MD=-2.19, 95%CI[-2.74,-1.63], P<0.001), imaging recovery time(MD=-2.17, 95%CI[-2.76,-1.58], P<0.001) and post-treatment CRP(MD=-4.07, 95%CI[-6.39,-1.75], P<0.001] were all significantly lower than those of the control group. However, it did not proved that the experimental group was safer than the control group(RR=0.84, 95%CI[0.57, 1.24], P=0.382). The results confirmed that Lianhua Qingwen combined with conventional Western medicine in the treatment of pneumonia could improve the clinical treatment efficiency, shorten the time of fever, cough, rale disappearance and imaging recovery, improve CRP index and accelerate the recovery of pneumonia patients. However, the literatures included in this study had a low quality, and the conclusions still need to be further confirmed by more high-quality, multi-center, rigorously designed randomized controlled trial.


Assuntos
Adulto , Humanos , Tosse , Medicamentos de Ervas Chinesas/efeitos adversos , Pneumonia/tratamento farmacológico , Resultado do Tratamento
13.
Nat Commun ; 10(1): 1769, 2019 04 16.
Artigo em Inglês | MEDLINE | ID: mdl-30992435

RESUMO

Three-dimensional topological nodal lines, the touching curves of two bands in momentum space, which give rise to drumhead surface states, provide an opportunity to explore a variety of exotic phenomena. However, solid evidence for a flat drumhead surface state remains elusive. In this paper, we report a realization of three-dimensional nodal line dispersions and drumhead surface states in phononic crystal. Profiting from its macroscopic nature, the phononic crystal permits a flexible and accurate fabrication for materials with ring-like nodal lines and drumhead surface states. Phononic nodal rings of the lowest two bands and, more importantly, topological drumhead surface states are unambiguously demonstrated. Our system provides an ideal platform to explore the intriguing properties of acoustic waves endowed with extraordinary dispersions.

14.
Nat Mater ; 17(11): 993-998, 2018 11.
Artigo em Inglês | MEDLINE | ID: mdl-30349029

RESUMO

Valley topological materials, in which electrons possess valley pseudospin, have attracted a growing interest recently. The additional valley degree of freedom offers a great potential for its use in information encoding and processing. The valley pseudospin and valley edge transport have been investigated in photonic and phononic crystals for electromagnetic and acoustic waves, respectively. In this work, by using a micromanufacturing technology, valley topological materials are fabricated on silicon chips, which allows the observation of gyral valley states and valley edge transport for elastic waves. The edge states protected by the valley topology are robust against the bending and weak randomness of the channel between distinct valley Hall phases. At the channel intersection, a counterintuitive partition of the valley edge states manifests for elastic waves, in which the partition ratio can be freely adjusted. These results may enable the creation of on-chip high-performance micro-ultrasonic materials and devices.

15.
Artigo em Chinês | WPRIM (Pacífico Ocidental) | ID: wpr-665420

RESUMO

Objective To observe the effect of Kidney-nourishing, Blood-activating, Phlegm-resolving and Resuscitation-inducing Decoction(KBPRD)on the expression of N-methyl-D-aspartate(NMDA)receptor subtype 1,2A,2B(NR1,NR2A,NR2B)in the cochlear spiral ganglion neurons(SGN)of tinnitus rats and to explore its mechanism, thus to provide experimental evidence for the treatment of tinnitus with KBPRD. Methods Sixty rats were randomly divided into normal group,model group,western medicine group,and low-,middle-,and high-dose Chinese medicine groups, 10 rats in each group. Rats were given intraperitoneal injection of sodium salicylate combined with water deprivation to induce tinnitus model. After successful establishment of the model, the rats in low-,middle-,and high-dose Chinese medicine groups were given gastric administration of KBPRD in the dosage of 5.5, 11, 22 g·kg-1·d-1 respectively, the rats in western medicine group were given gastric administration of 5 mg·kg-1·d-1 of carbamazepine,and rats in the model group and normal group were given gastric administration of 2 mL of normal saline,once every day,treatment time covering 8 weeks. The expression levels of NR1,NR2A,and NR2B in the cochlear SGN was detected by immunoblotting and real-time quantitative reverse transcription-polymerase chain reaction(qRT-PCR)after 8 weeks of treatment. Results Compared with the normal group,the expression levels of NR1, NR2A and NR2B in the model group were increased, the difference being significant (P < 0.05). Compared with the model group,the expression of NR1,NR2A and NR2B in low-,middle-,and high-dose Chinese medicine groups were significantly decreased(P<0.05).Conclusion KBPRD is effective on relieving tinnitus of rats, and its mechanism is correlated with lowering the increased expression of NR1,NR2A and NR2B in SGN of tinnitus rats.

16.
Artigo em Chinês | WPRIM (Pacífico Ocidental) | ID: wpr-489530

RESUMO

Based on link control concepts, the life cycle of science and technology projects was divided into five stages,, such as project application, selection, implementation, output and assessment.All the science misconducts that might occur among these five stages were listed.Finally, different precautions were made to prevent different misconducts during different stage..

17.
Artigo em Chinês | WPRIM (Pacífico Ocidental) | ID: wpr-465504

RESUMO

ObjectiveTo observe the clinical efficacy of warming-unblocking Yin Heel Vessel plus rehabilitation training in treating post-stroke strephenopodia, for seeking the optimal treatment protocol.MethodNinety eligible subjects withpost-stroke strephenopodia were randomized into an acupuncture group, a rehabilitation group, and a united group, to respectively receive warming-unblocking Yin Heel Vessel, rehabilitation treatment, and warming-unblocking Yin Heel Vessel plus rehabilitation training. ResultTwo treatment courses later, there was no significant difference in comparing the strephenopodia score between the acupuncture group and rehabilitation group (P>0.05); the strephenopodia score in the united group was significantly different from that in the acupuncture group and rehabilitation group (P<0.05), and the improvement in strephenopodia in the united group was superior to that in both acupuncture group and rehabilitation group.ConclusionWarming-unblocking Yin Heel Vessel plus rehabilitation can produce a content efficacy in treating post-stroke strephenopodia.

18.
Chinese Journal of Epidemiology ; (12): 335-338, 2005.
Artigo em Chinês | WPRIM (Pacífico Ocidental) | ID: wpr-331882

RESUMO

<p><b>OBJECTIVE</b>To evaluate the effectiveness of stroke prevention among high risk population, using Nao'an Capsules.</p><p><b>METHODS</b>Participants were selected from 696,558 residents in Nanhui, using county of Shanghai city. Individuals aged 35 years old and over with at least one risk factor exposure to stroke, received cerebral vascular hemodynamic examination. 18,271 cases meeting the criteria of cerebral vascular hemodynamic indexes accumulative score below 70 points were defined as individuals with high-risk and targets to receive intervention. According to the willingness of the participants, 10,313 cases received Nao'an Capsules for intensive intervention based on general intervention measures compared to 7958 cases only receiving general intervention. After the implementation of intervention, incidence and mortality rates of stroke and the effectiveness of three-year intervention were studied.</p><p><b>RESULTS</b>Incidence of stroke in Nao'an Capsules group was significantly lower than that of the general intervention (P < 0.01) with 53.8% in males and 58.4% in females. The relative risk (RR) in two gender groups were 0.46 (0.33 - 0.64) and 0.39 (0.30 - 0.50) respectively. Multiple logistic regression analysis indicated that the history of hypertension, accumulative score of cerebral vascular hemodynamic indexes, age, gender and Nao'an Capsules intervention were the variables selected into the equation and significantly related to stroke. Among the variables, Nao'an Capsule was the strongest factor with a RR of 0.41.</p><p><b>CONCLUSION</b>Incidence of stroke in Nao'an Capsule intervention group was significantly lower than that in the general intervention group after 3 years of intervention, suggesting that Nao'an Capsule intervention was the strongest factor affecting stroke occurrence in individuals at high-risk.</p>


Assuntos
Adulto , Idoso , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Cápsulas , China , Epidemiologia , Medicamentos de Ervas Chinesas , Usos Terapêuticos , Educação em Saúde , Incidência , Modelos Logísticos , Fitoterapia , Fatores de Risco , Acidente Vascular Cerebral , Epidemiologia
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