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1.
Nat Mater ; 22(10): 1203-1209, 2023 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-37349396

RESUMO

Topological photonics is rapidly expanding. However, discovering three-dimensional topological electromagnetic systems can be more challenging than electronic systems for two reasons. First, the vectorial nature of electromagnetic waves results in complicated band dispersions, and simple tight-binding-type predictions usually fail. Second, topological electromagnetic surface modes inside the light cone have very low quality factors (Q factors). Here, we propose the concept of scalar topological photonics to address these challenges. Our approach is experimentally validated by employing a nested meta-crystal configuration using connected coaxial waveguides. They exhibit scalar-wave-like band dispersions, making the search for photonic topological phases an easier task. Their surface states have skyrmion-like electric field distributions, resulting in a whole, bright surface state band inside the light cone continuum. As such, the topological surface states in our three-dimensional nested crystals can be exposed to air, making such systems well-suited for practical applications.

2.
Zhen Ci Yan Jiu ; 48(4): 325-30, 2023 Apr 25.
Artigo em Chinês | MEDLINE | ID: mdl-37186195

RESUMO

OBJECTIVE: To explore the effect of electroacupuncture (EA) on sterol regulatory element-binding protein (SREBP) cleavage-activating protein (SCAP)/ SREBP-2 signaling and the expressions of its downstream cholesterol metabolism related molecules 3-hydroxy-3-methylglutaryl-CoA reductase (HMGCR), proprotein convertase subtilisin/kexin type 9 (PCSK9), and low-density lipoprotein receptor (LDLR) in the liver tissue in rats with hyperlipidemia (HLP), so as to reveal its mechanisms underlying improvement of HLP. METHODS: Male SD rats were randomly divided into normal control, HLP model and EA groups (n=10/group). The HLP model was established by feeding the rats with high-fat diet for 28 d. Rats in the EA group received EA stimulation (2 Hz/100 Hz, 2 mA) at "Fenglong" (ST40) and "Yinlingquan"(SP9) for 30 min, once daily for 28 d. The contents of total cholesterol (TC), triglyceride (TG), high density lipoprotein-cholesterol (HDL-C), low-density lipoprotein cholesterol (LDL-C) in the serum, the activity of glutamic oxaloacetic transaminase (AST) and glutamic pyruvic transaminase (ALT) were detected by automatic biochemical analysis. The content of TC in the liver tissue was detected using high performance liquid chromatography. The mRNA and protein expression levels of SCAP, SREBP-2, HMGCR, PCSK9 and LDLR in the liver tissue were measured by using quantitative real-time PCR and Western blot, respectively. The immunofluorescence density of liver SCAP was determined by using immunofluorescence histochemistry. RESULTS: Compared with the normal control group, the contents of liver TC, serum TC, LDL-C, the activities of AST and ALT, and the mRNA and protein expression levels of SCAP, SREBP-2, HMGCR, PCSK9 as well as SCAP immunoactivity were significantly increased (P<0.01), while the LDLR mRNA and protein levels were markedly decreased (P<0.01) in the model group. In comparison with the model group, the contents of liver TC, serum TC, LDL-C, the activities of AST and ALT and the expression of SCAP, SREBP-2, HMGCR, PCSK9 mRNAs and proteins and SCAP immunoactivity were considerably decreased in the EA group (P<0.01), while the LDLR protein level was evidently increased in the EA group (P<0.05). CONCLUSION: EA intervention can inhibit the synthesis of cholesterol in the liver and thus improve hyperlipidemia in HLP rats, which may be realized by down-regulating the protein and mRNA expressions of hepatic SCAP/SREBP-2, HMGCR and PCSK9, and up-regulating LDLR protein.


Assuntos
Eletroacupuntura , Hiperlipidemias , Doenças Metabólicas , Animais , Masculino , Ratos , Colesterol/metabolismo , LDL-Colesterol/metabolismo , Hiperlipidemias/genética , Hiperlipidemias/terapia , Fígado , Doenças Metabólicas/metabolismo , Pró-Proteína Convertase 9/genética , Pró-Proteína Convertase 9/metabolismo , Ratos Sprague-Dawley , RNA Mensageiro/metabolismo , Proteína de Ligação a Elemento Regulador de Esterol 1/metabolismo , Proteína de Ligação a Elemento Regulador de Esterol 2/genética , Proteína de Ligação a Elemento Regulador de Esterol 2/metabolismo
3.
Medicine (Baltimore) ; 102(14): e33125, 2023 Apr 07.
Artigo em Inglês | MEDLINE | ID: mdl-37026956

RESUMO

To explore the value of artificial intelligence combined with musculoskeletal ultrasound in the differential diagnosis of pain rehabilitation of scapulohumeral periarthritis. A total of 165 patients with periarthritis of the shoulder, who were admitted to our hospital from January 2020 to January 2022, were selected. Konica SONIMAGE HS1 PLUS color Doppler ultrasound diagnostic instrument was used to detect muscles and bones of patients with scapulohumeral periarthritis. This study proposed an intelligent clustering analysis algorithm with musculoskeletal ultrasound parameters. The neural network was trained on a GeForce RTX 3060 with the Adam W optimizer, a batch size of 12, and an initial learning rate of 5E-4. Each batch of 2 types of trained samples was input into the network in a specific proportion. Pain was assessed on a 10-point visual analogue scale. On the affected side of scapulohumeral periarthritis, the mild pain group showed thickening of the shoulder posterior capsule (2.02 ± 0.72) mm with clear edges. In the moderate pain group, the thickness of the shoulder posterior capsule gradually narrowed (1.01 ± 0.38) mm and became even thinner than that of the unaffected side, with irregular and blurred edges. In the severe pain group, the thickness of the shoulder posterior capsule largely returned to normal (1.21 ± 0.42) mm, and the edge was clear. Multivariate logistic regression showed that in addition to musculoskeletal ultrasound parameters, the length of service, work nature, and the busy degree of work of patients with periarthritis of the shoulder were significant factors that influenced shoulder periarthritis pain (P < .05). The performance of the proposed intelligent auscultation algorithm was further examined in a clinical setting, in which we used 165 clinical musculoskeletal ultrasound samples (including 81 positive and 84 negative samples) as a test set. The accuracy, sensitivity, and specificity were 0.833, 0.872, and 0.801, respectively. Musculoskeletal ultrasound combined with artificial intelligence algorithm is a new diagnostic and staging tool for scapulohumeral periarthritis.


Assuntos
Periartrite , Humanos , Inteligência Artificial , Diagnóstico Diferencial , Ombro , Dor de Ombro
4.
Phys Rev Lett ; 129(4): 043902, 2022 Jul 22.
Artigo em Inglês | MEDLINE | ID: mdl-35939009

RESUMO

That disorder can induce nontrivial topology is a surprising discovery in topological physics. As a typical example, Chern topological Anderson insulators (TAIs) have been realized in photonic systems, where the topological phases exist without symmetry protection. In this Letter, by taking transverse magnetic and transverse electric polarizations as pseudospin degrees of freedom, we theoretically propose a scheme to realize disorder-induced symmetry-protected topological phase transitions in two-dimensional photonic crystals with a combined time-reversal, mirror, and duality symmetry T_{f}=TM_{z}D. In particular, we demonstrate that the disorder-induced symmetry-protected topological phase persists even without pseudospin conservation, thereby realizing a photonic Z_{2} TAI, in contrast to a Z-classified quantum spin Hall (QSH) TAI with decoupled spins. By formulating a new scattering approach, we show that the topology of both the QSH and Z_{2} TAIs can be manifested by the accumulated spin rotations of the reflected waves from the photonic crystals. Using a transmission structure, we also illustrate the trivialization of a disordered QSH phase with an even integer topological index caused by spin coupling.

5.
Nat Commun ; 12(1): 6471, 2021 Nov 09.
Artigo em Inglês | MEDLINE | ID: mdl-34753932

RESUMO

Very recently, increasing attention has been focused on non-Abelian topological charges, e.g., the quaternion group Q8. Different from Abelian topological band insulators, these systems involve multiple entangled bulk bandgaps and support nontrivial edge states that manifest the non-Abelian topological features. Furthermore, a system with an even or odd number of bands will exhibit a significant difference in non-Abelian topological classification. To date, there has been scant research investigating even-band non-Abelian topological insulators. Here, we both theoretically explore and experimentally realize a four-band PT (inversion and time-reversal) symmetric system, where two new classes of topological charges as well as edge states are comprehensively studied. We illustrate their difference in the four-dimensional (4D) rotation sense on the stereographically projected Clifford tori. We show the evolution of the bulk topology by extending the 1D Hamiltonian onto a 2D plane and provide the accompanying edge state distributions following an analytical method. Our work presents an exhaustive study of four-band non-Abelian topological insulators and paves the way towards other even-band systems.

6.
Nature ; 594(7862): 195-200, 2021 06.
Artigo em Inglês | MEDLINE | ID: mdl-34108697

RESUMO

In the last few decades, topological phase1-11 has emerged as a new classification of matter states beyond the Ginzburg-Landau symmetry-breaking paradigm. The underlying global invariant is usually well characterized by integers, such as Chern numbers or winding numbers-the Abelian charges12-15. Very recently, researchers proposed the notion of non-Abelian topological charges16-19, which possess non-commutative and fruitful braiding structures with multiple (more than one) bandgaps tangled together. Here we experimentally observe the non-Abelian topological charges in a time-reversal and inversion-symmetric transmission line network. The quaternion-valued non-Abelian topological charges are clearly mapped onto an eigenstate-frame sphere. Moreover, we find a non-Abelian quotient relation that provides a global perspective on the distribution of edge/domain-wall states. Our work opens the door towards characterization and manipulation of non-Abelian topological charges, which may lead to interesting observables such as trajectory-dependent Dirac/Weyl node collisions in two-dimensional systems16,17,20, admissible nodal line configurations in three dimensions16,19,20, and may provide insight into certain strongly correlated phases of twisted bilayer graphene21.

7.
Phys Rev Lett ; 126(6): 067401, 2021 Feb 12.
Artigo em Inglês | MEDLINE | ID: mdl-33635715

RESUMO

We have theoretically and experimentally achieved large-area one-way transport by using heterostructures consisting of a domain of an ordinary photonic crystal sandwiched between two domains of magnetic photonic crystals. The nonmagnetized domain carries two orthogonal one-way waveguide states which have amplitude uniformly distributed over a large area. We show that such one-way waveguide states can be used to abruptly narrow the beam width of an extended state to concentrate energy, and the transport is robust against different kinds of defects and imperfections. They are also immune to the Anderson-type localization when large randomness is introduced.

8.
Zhen Ci Yan Jiu ; 46(1): 33-8, 2021 Jan 25.
Artigo em Chinês | MEDLINE | ID: mdl-33559423

RESUMO

OBJECTIVE: To observe the effects of electroacupuncture on the hypothalamic Toll-like receptor 4 (TLR4)/ inhibitor nuclear factor kappa-B α(IκBα)/nuclear factor-κB (NF-κB) signaling pathway in obese insulin resistance (OIR) rats,so as to explore the mechanism of EA underlying improving of insulin resistance. METHODS: Rats were randomly divided into normal, model and EA groups, with 8 rats in each group. The rat model of OIR was established by feeding with high-fat diet for 8 weeks. EA(2 Hz,1 mA)was applied to unilateral"Zusanli"(ST36),"Fenglong"(ST40),"Zhongwan"(CV12)and"Guanyuan"(CV4)for 10 min, 3 times a week for 8 weeks. The body mass, fasting blood glucose(FBG) and postprandial blood glucose (PBG) were measured before and after 2、4、6、8 weeks' intervention. An intraperitoneal injection glucose tolerance test and hyperglycemic clamps were applied to test insulin resistance. The expression of TLR4、p-IκBα、NF-κB p65、TNF-α、IL-1ß mRNA and protein in hypothalamus was detected by quantitative real-time PCR and Western blot, separately. RESULTS: Compared with the normal group, the body mass and PBG of the model group were significantly increased (P<0.01); glucose infusion rate(GIR) was significantly reduced (P<0.01); in the IPGTT test, the increase in blood glucose was significantly greater after 90 and 120 min of glucose injection(P<0.01); the hypothalamus TLR4, NF-κB p65,p-IκBα, TNF-α, IL-1ß mRNA and protein expressions were all significantly increased (P<0.01). After EA intervention, the body weight and PBG were significantly down-regulated after 6 weeks and 2 weeks of intervention (P<0.05, P<0.01); GIR were significantly up-regulated after 8 weeks of intervention (P<0.05); In the IPGTT test, the increase in blood glucose 60 min after glucose injection was significantly down-regulated (P<0.05); hypothalamus TLR4, NF-κB p65,p-IκBα, TNF-α, IL -1ß mRNA and protein expression were significantly down-regulated (P<0.01). CONCLUSION: EA can reduce the body weight of OIR rats and improve IR, which may be related to down-regulating the hypothalamic TLR4/IκBα/NF-κB signaling pathway.


Assuntos
Eletroacupuntura , Resistência à Insulina , Pontos de Acupuntura , Animais , Hipotálamo/metabolismo , Resistência à Insulina/genética , Inibidor de NF-kappaB alfa/genética , NF-kappa B/genética , NF-kappa B/metabolismo , Obesidade/genética , Obesidade/terapia , Ratos , Ratos Wistar , Transdução de Sinais , Receptor 4 Toll-Like/genética
9.
Science ; 370(6520): 1077-1080, 2020 11 27.
Artigo em Inglês | MEDLINE | ID: mdl-33243886

RESUMO

Branch-point singularities known as exceptional points (EPs), which carry a nonzero topological charge, can emerge in non-Hermitian systems. We demonstrate with both theory and acoustic experiments an "exceptional nexus" (EX), which is not only a higher-order EP but also the cusp singularity of multiple exceptional arcs (EAs). Because the parameter space is segmented by the EAs, the EX possesses a hybrid topological invariant (HTI), which consists of distinct winding numbers associated with Berry phases accumulated by cyclic paths on different complex planes. The HTI is experimentally characterized by measuring the critical behaviors of the wave functions. Our findings constitute a major advance in the fundamental understanding of non-Hermitian systems and their topology, possibly opening new avenues for applications.

10.
Arthritis Res Ther ; 21(1): 120, 2019 05 14.
Artigo em Inglês | MEDLINE | ID: mdl-31088511

RESUMO

BACKGROUND: Conditioned pain modulation (CPM) is impaired in people with chronic pain such as knee osteoarthritis (KOA). The purpose of this randomized, controlled clinical trial was to investigate whether strong electroacupuncture (EA) was more effective on chronic pain by strengthening the CPM function than weak EA or sham EA in patients with KOA. METHODS: In this multicenter, three-arm parallel, single-blind randomized controlled trial, 301 patients with KOA were randomly assigned. Patients were randomized into three groups based on EA current intensity: strong EA (> 2 mA), weak EA (< 0.5 mA), and sham EA (non-acupoint). Treatments consisted of five sessions per week, for 2 weeks. Primary outcome measures were visual analog scale (VAS), CPM function, and Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC). RESULTS: Three hundred one patients with KOA were randomly assigned, among which 271 (90.0%) completed the study (mean age 63.93 years old). One week of EA had a clinically important improvement in VAS and WOMAC but not in CPM function. After 2 weeks treatment, EA improved VAS, CPM, and WOMAC compared with baseline. Compared with sham EA, weak EA (3.8; 95% CI 3.45, 4.15; P < .01) and strong EA (13.54; 95% CI 13.23, 13.85; P < .01) were better in improving CPM function. Compared with weak EA, strong EA was better in enhancing CPM function (9.73; 95% CI 9.44, 10.02; P < .01), as well as in reducing VAS and total WOMAC score. CONCLUSION: EA should be administered for at least 2 weeks to exert a clinically important effect on improving CPM function of KOA patients. Strong EA is better than weak or sham EA in alleviating pain intensity and inhibiting chronic pain. TRIAL REGISTRATION: This study was registered with the Chinese Clinical Trial Registry ( ChiCTR-ICR-14005411 ), registered on 31 October 2014.


Assuntos
Eletroacupuntura/métodos , Osteoartrite do Joelho/terapia , Idoso , Dor Crônica/etiologia , Dor Crônica/terapia , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Resultado do Tratamento
11.
Zhen Ci Yan Jiu ; 44(3): 205-10, 2019 Mar 25.
Artigo em Chinês | MEDLINE | ID: mdl-30945504

RESUMO

OBJECTIVE: To evaluate the effectiveness and safety of internal heat-type acupuncture needle (IHTAN) the-rapy in the treatment of post-stroke shoulder pain in apopletic patients. METHODS: According to the random number table, 96 patients with post-stroke shoulder pain were divided into IHTAN group and warm needle moxibustion group (n=48 in each one). Jianyu (LI15), Jianliao (TE14), Jianzhen (SI9), Binao (LI14) and Ashi points (Extra) on the affected side were selected in the two groups. For patients of the IHTAN group, internal warmth controllable acupuncture needles were inserted into the above-mentioned acupoints, and then connected to an internal heat acupuncture apparatus for stimulating the acupoints at 42 ℃, 20 min every time, once a week, for 4 weeks. For patients of the warm needle moxibustion group, the above mentioned acupoints were stimulated with filiform needles attached with an ignited moxa-stick, once every other day, for 4 weeks. If the shoulder pain disappeared or basically disappeared, it was considered to be healed, if the pain was relieved, it was considered to be effective, ot-herwise, it was considered to be ineffective. The incidence of local skin injury including burn, empyrosis, silt blue, hematoma and infection, the heart rate, respiration, blood pressure, oxyhemoglobin saturation, blood routine (hemoglobin level, white blood cell [WBC] count, platelet count), creatase and dipolymer levels were recorded or detected. Additionally, the patients' satisfaction rate about the treatment environment was recorded. RESULTS: Following the treatment, of the 45 and 47 cases in the warm needle moxibustion and IHTAN groups, 5 (11.11%) and 20 (42.55%) were cured, 26(57.78%) and 21(44.68%) experienced marked improvement, and 14 (31.11%) and 6 (12.77%) had no apparent changes in their shoulder pain severity, with the total effective rates being 68.89% and 87.23%, respectively. The curative rate and total effective rate of the IHTAN group were significantly higher than those of the warm needle moxibustion group (P<0.01,P<0.05). The incidence of skin injury of the IHTAN group was evidently lower than that of the warm needle moxibustion group (P<0.01), and the patients' therapeutic environment satisfaction rate was remarkably higher in the IHTNA group than in the warm needle moxibustion group (P<0.05). No significant differences were found between the two groups and between pre- and post-treatment in each group in the heart rate, respiration frequency, systolic and diastolic pressures, oxyhemoglobin saturation, hemoglobin content, WBC count, platelet count, and plasma dipolymer, creatine kinase, lactic dehydrogenase, and beta-hydroxybutyrate dehydrogenase levels (P>0.05). CONCLUSION: The IHTAN therapy is effective, safe and reliable in the treatment of post-stroke shoulder pain. In terms of the incidence of skin injury and the satisfaction degree of therapeutic environment, the internal heat-type acupuncture needle therapy is obviously superior to the warm needle moxibustion therapy.


Assuntos
Moxibustão , Acidente Vascular Cerebral , Pontos de Acupuntura , Temperatura Alta , Humanos , Agulhas , Dor de Ombro/terapia , Resultado do Tratamento
12.
Zhen Ci Yan Jiu ; 44(1): 51-6, 2019 Jan 25.
Artigo em Chinês | MEDLINE | ID: mdl-30773863

RESUMO

OBJECTIVE: To observe the short-term and long-term therapeutic effects of internal heat-type acupuncture needle (IHTAN) therapy combined with acupoint injection of O3for post-stroke shoulder pain in apopletic patients. METHODS: Patients with post-stroke shoulder pain were divided into warm needle moxibustion + acupoint injection group (29 cases), acupoint injection group (30 cases) and IHTAN+acupoint injection group (29 cases) according to the random number table. For acupoint injection, O3 solution (3 mL, 30 µg/mL) was injected into Jianyu (LI15), Jianliao (SJ14), Jianzhen (LI9), Binao (LI14) and Ashi points (4-6 acupoints every time) on the affected side, once every other day for 4 weeks. For warm needle moxibustion, the above mentioned acupoints were stimulated with filiform needles attached with an ignited moxa-stick, once every other day for 4 weeks. For IHTAN, the internal warmth controllable acupuncture needles were inserted into the above mentioned acupoints on the affected side, and then connected to an internal heat acupuncture apparatus for stimulating the acupoints at 42 ℃, 20 min every time, once a week, for 4 weeks. The severity of shoulder pain was assessed by using visual analogue scale (VAS, 0-10 points), the upper limb joint motion function evaluated using Fugl-Meyer assessment scale (FMA, 0-66 points), and the ability of daily living activities (ADL) evaluated using Barthel index (0-100 points) at the ends of the 2nd and 4th week as well as the 6th month after the treatment. If the shoulder pain disappeared or basically disappeared, it was considered to be healed. If the pain was relieved, it was considered to be effective. Otherwise, it was considered to be ineffective. RESULTS: At the ends of the 2nd and 4th week as well as the 6th month after the treatment, the VAS scores of the IHTAN+acupoint injection group were significantly lower than those of the warm needle moxibustion+acupoint injection and acupoint injection groups (P<0.05), and the FMA and ADL scores were significantly higher in the IHTAN+acupoint injection group than in the other two groups (P<0.05). No significant differences were found between the warm needle moxibustion+acupoint injection and the acupoint injection groups in the scores of VAS, FMA and ADL (P>0.05). Of the 29, 30 and 29 cases in the warm needle moxibustion+acupoint injection, acupoint injection and IHTNA+acupoint injection groups, 1, 0 and 7 cases at the 2nd week, 3, 2 and 12 cases at the 4th week, 4, 2 and 15 cases at the 6th month were cured; 15, 14 and 16 cases at the 2nd week, 17, 17 and 13 cases at the 4th week, and 18, 18 and 12 cases at the 6th month experienced marked improvement; 13, 16 and 6 cases at the 2nd week, 9, 11 and 4 cases at the 4th week, 7, 10 and 2 cases at the 6th month had no apparent changes in their shoulder pain severity, with the total effective rates at the 4th week and 6th month being 68.97% and 75.86%, 63.33% and 66.60%, and 86.21% and 93.10%, respectively. CONCLUSION: The internal heat-type acupuncture needle therapy combined with O3 acupoint injection has obvious short-term and long-term therapeutic effects for post-stroke shoulder pain and is obviously superior to warm needle moxibustion+ acupoint injection and simple acupoint injection in relieving shoulder pain and improving upper limb motion function.


Assuntos
Dor de Ombro/terapia , Acidente Vascular Cerebral , Pontos de Acupuntura , Temperatura Alta , Humanos , Agulhas , Dor de Ombro/etiologia , Acidente Vascular Cerebral/complicações , Resultado do Tratamento
13.
Nat Commun ; 9(1): 2086, 2018 05 25.
Artigo em Inglês | MEDLINE | ID: mdl-29802280

RESUMO

Propagation behaviors of electromagnetic waves are governed by the equifrequency surface of the medium. Up to now, ordinary materials, including the medium exist in nature and the man-made metamaterials, always have an equifrequency surface (ellipsoid or hyperboloid) centered at zero k-point. Here we propose a new type of metamaterial possessing multiple index ellipsoids centered at arbitrary nonzero k-points. Their locations in momentum space are determined by the connectivity of a set of interpenetrating metallic scaffolds, whereas the group velocities of the modes are determined by the geometrical details. Such system is a new class of metamaterial whose properties arise from global connectivity and hence can have broadband functionality in applications such as negative refraction, orientation-dependent coupling effect, and cavity without walls, and they are fundamentally different from ordinary resonant metamaterials that are inherently bandwidth limited. We perform microwave experiments to confirm our findings.

14.
Sci Rep ; 8(1): 5160, 2018 Mar 26.
Artigo em Inglês | MEDLINE | ID: mdl-29581466

RESUMO

Bound states in the continuum usually refer to the phenomenon of a single or a few discrete bound states embedded in a continuous spectrum of extended states. Here we propose a simple mechanism to achieve a band of bound states in the continuum in a class of disordered quasi-1D and quasi-2D systems, where the bound states and extended states overlap completely in a spectral range. The systems are partially disordered in a way that a band of extended states always exists, not affected by the randomness, whereas the states in all other bands become localized and cover the entire spectrum of extended states. We demonstrate such disordered-induced bound states in the continuum in disordered multi-chain and multi-layer systems.

15.
Phys Rev Lett ; 118(16): 166803, 2017 Apr 21.
Artigo em Inglês | MEDLINE | ID: mdl-28474943

RESUMO

We propose and experimentally realize a new kind of bound states in the continuum (BICs) in a class of systems constructed by coupling multiple identical one-dimensional chains, each with inversion symmetry. In such systems, a specific separation of the Hilbert space into a topological and a nontopological subspace exists. Bulk-boundary correspondence in the topological subspace guarantees the existence of a localized interface state which can lie in the continuum of extended states in the nontopological subspace, forming a BIC. Such a topological BIC is observed experimentally in a system consisting of coupled acoustic resonators.

16.
Sci Rep ; 6: 38049, 2016 12 01.
Artigo em Inglês | MEDLINE | ID: mdl-27905504

RESUMO

Robust topological edge modes may evolve into complex-frequency modes when a physical system becomes non-Hermitian. We show that, while having negligible forward optical extinction cross section, a conjugate pair of such complex topological edge modes in a non-Hermitian -symmetric system can give rise to an anomalous sideway scattering when they are simultaneously excited by a plane wave. We propose a realization of such scattering state in a linear array of subwavelength resonators coated with gain media. The prediction is based on an analytical two-band model and verified by rigorous numerical simulation using multiple-multipole scattering theory. The result suggests an extreme situation where leakage of classical information is unnoticeable to the transmitter and the receiver when such a -symmetric unit is inserted into the communication channel.

17.
Nat Commun ; 6: 8183, 2015 Sep 23.
Artigo em Inglês | MEDLINE | ID: mdl-26395967

RESUMO

If a system possesses a spin or pseudospin, which is locked to the linear momentum, spin-polarized states can exhibit backscattering-immune transport if the scatterer does not flip the spin. Good examples of such systems include electronic and photonic topological insulators. For electromagnetic waves, such pseudospin states can be achieved in metamaterials with very special artificial symmetries; however, these bulk photonic topological insulators are usually difficult to fabricate. Here we propose a paradigm in which the pseudospin is enforced simply by imposing special boundary conditions inside a channel. The symmetry-protected pseudospin states are guided in air and no bulk material is required. We also show that the special boundary conditions can be implemented simply using an array of metallic conductors, resulting in spin-filtered waveguide with a simple structure and a broad working bandwidth. We generate several conceptual designs, and symmetry-protected pseudospin transport in the microwave regime is experimentally indicated.

18.
Trials ; 16: 131, 2015 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-25873092

RESUMO

BACKGROUND: Previous studies have shown that electroacupuncture (EA) has a significant effect on acute pain, but it has not solved the clinical problem of the chronification of acute pain. Diffuse noxious inhibitory controls (DNIC) function as a reliable indicator to predict the risk of chronic pain events. DNIC function in knee osteoarthritis (KOA) patients has been demonstrated to gradually decrease during the development of chronic pain. The purpose of this study is to conduct a randomized, controlled clinical trial to determine if EA can repair impaired DNIC function and thus prevent chronification of the acute pain of KOA. METHODS/DESIGN: This is a multicenter, single blind, randomized, controlled, three-arm, large-scale clinical trial. A total of 450 KOA patients will be randomly assigned to three groups. The strong EA group will receive EA with high-intensity current (2 mA < current < 5 mA) at the ipsilateral 'Neixiyan' (EX-LE5), 'Dubi'(ST35), 'Liangqiu'(ST34) and 'Xuehai' (SP10). The weak EA group will receive EA with low-intensity current (0 mA < current < 0.5 mA) on the same acupoints. The sham EA group will receive EA with low-intensity current (0 mA < current < 0.5 mA) with fine needles inserted superficially into the sites 2 cm lateral to the above acupoints. The patients will be treated with EA once a day, 30 minutes per session, in 5 sessions per week, for 2 weeks. In order to determine the best stage of KOA for effective EA intervention, patients within the treatment groups also will be divided into four stages. The primary outcomes are Visual Analog Scale (VAS), DNIC function and the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC). Clinical assessments will be evaluated at baseline (before treatment) and after 5 to 10 sessions of treatment. DISCUSSION: This trial will be helpful in identifying whether strong EA is more effective than weak EA in reversing chronification of acute pain through repairing the impaired DNIC function and in screening for the best stage of KOA for effective EA intervention. TRIAL REGISTRATION: Chinese Clinical Trial Registry Number: ChiCTR-ICR-14005411. The date of registration is 31 October 2014.


Assuntos
Dor Aguda/terapia , Protocolos Clínicos , Eletroacupuntura , Osteoartrite do Joelho/terapia , Humanos , Avaliação de Resultados em Cuidados de Saúde , Tamanho da Amostra , Método Simples-Cego
19.
Guang Pu Xue Yu Guang Pu Fen Xi ; 32(2): 334-8, 2012 Feb.
Artigo em Chinês | MEDLINE | ID: mdl-22512163

RESUMO

Cationic degree has been investigated as an important factor in polyacrylamide materials. Diallyl dimethyl ammonium chloride and acrylamide (PDA) was grafted by free radical polymerisation of acrylamide monomer (AM) onto the cationic monomer dimethyl diallyl ammonium chloride (DMDAAC). In the present study, near infrared reflectance spectroscopy (NIRS) was used as a rapid and accurate method to determine the cationic degree in the PDA. In this experiment, the near infrared spectra of 37 PDA samples that were self-prepared in the laboratory from 900.00 to 1 700.00 were collected. The characteristic peaks and the entire spectrum segment as the input layer neurons in radical basis function (RBF) were investigated for establishing the mathematical conversion NIRS calibration mode. For reduction of the NIR spectrum noise, the wavelet analysis was used as pretreatment process. The measured value was determined by using precipitation titration and a comparison between the simulated value and measured value was made. It was found that the external validation determination coefficient was more than 0.9, and the simulation value is in good agreement with the measured value. The statistics analysis showed that there was no significant difference between simulated value and measured value. Therefore, the calibration model (RBF neural network) established in this paper exhibited a remarkable feasibility for predicting the cationic degree of PDA based on the near infrared spectroscopy.

20.
Phys Rev Lett ; 107(10): 105506, 2011 Sep 02.
Artigo em Inglês | MEDLINE | ID: mdl-21981513

RESUMO

We propose a type of elastic metamaterial comprising fluid-solid composite inclusions which can possess a negative shear modulus and negative mass density over a large frequency region. Such a material has the unique property that only transverse waves can propagate with a negative dispersion while longitudinal waves are forbidden. This leads to many interesting phenomena such as negative refraction, which is demonstrated by using a wedge sample and a significant amount of mode conversion from transverse waves to longitudinal waves that cannot occur on the interface of two natural solids.

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