Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 42
Filtrar
Mais filtros










Base de dados
Intervalo de ano de publicação
1.
Opt Lett ; 49(2): 367-370, 2024 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-38194570

RESUMO

We investigate optical transmission in cavity magnon polaritons and discover a complex multi-window magnetically induced transparency and a bistability with magnetic and optical characteristics. With the regulation of Kerr nonlinear effects and driven fields, a complex multi-window resonant transmission with fast and slow light effects appears, which includes transparency and absorption windows. The magnetically induced transparency and absorption can be explained by the destructive and constructive interference between different excitation pathways. Moreover, we demonstrate the bistability of magnons and photons with a hysteresis loop, where magnetic and optical bistabilities can induce and control each other. Our results pave a new way, to the best of our knowledge, for implementing a room-temperature multiband quantum memory.

2.
Phys Rev E ; 108(3-1): 034214, 2023 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-37849096

RESUMO

The nonlinear Landau-Zener-Stückelberg-Majorana (LZSM) tunneling dynamics and interferometry of an extended Bose-Hubbard flux ladder are studied. Based on the mean-field theory, the dispersion relation of the system is given, and it is found that loop structures periodically appear in the band structure and the nonlinear LZSM interference occurs naturally without Floquet engineering, which can be effectively modulated by atomic interactions. The nonlinear energy bands and the unique chirality feature of the flux ladder system can be identified through the dynamics of nonlinear Landau-Zener tunneling. Remarkably, the critical position of the noise in the interference pattern can be employed to identify the loop structure in the energy band, establishing an effective link between the nonlinear loop structure and LZSM interferometry. The position, intensity, symmetry, and width of interference patterns strongly depend on the magnetic field, atomic interactions, rung-to-leg coupling ratio, and energy bias, which provides an effective way to measure these parameters using the nonlinear LZSM interferometry. This paper further expands the dynamics of flux ladder systems to complex interaction regions and has potential applications in the precise measurement of related nonlinear systems.

3.
Phys Rev E ; 107(2-1): 024218, 2023 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-36932477

RESUMO

We study the ground-state stability of the trapped one-dimensional Bose-Einstein condensate under a density-dependent gauge field by variational and numerical methods. The competition of density-dependent gauge field and mean-field atomic interaction induces the instability of the ground state, which results in irregular dynamics. The threshold of the gauge field for exciting the instability is obtained analytically and confirmed numerically. When the gauge field is less than the threshold, the system is stable, and the gauge field induces chiral dynamics of the wave packet. When the gauge field is greater than the threshold, the system is unstable, and the ground-state wave packet will be deformed and fragmented. Interestingly, we find that as the gauge field approaches the threshold, strong dipolar and breathing dynamics take place, and strong modes mixing occurs, the instability of the system sets in. In addition, we show that the stability of the system can be well controlled by periodical modulation of the trapping potential. We provide theoretical evidence to understand and control the irregular dynamics associated with chiral superfluid induced by density-dependent gauge field.

4.
Phys Rev E ; 106(4-1): 044215, 2022 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-36397576

RESUMO

The two-leg magnetic ladder is the simplest and ideal model to reflect the coupling effects of lattice and magnetic field. It is of great significance to study some novel phases, topological characteristics, and chiral characteristics in condensed matter physics. In particular, the left-right leg degree of freedom can be regarded as a pseudospin, and the two-leg magnetic ladder also provides an ideal platform for the study of spin dynamics. Here the ground state, Bloch oscillations (BOs), and spin dynamics of the interacting two-leg magnetic ladder subject to an external linear force are studied by using variational approach and numerical simulation. In the absence of the external linear force, the critical condition of transition between the zero-momentum state and plane-wave state is obtained analytically, and the physical mechanism of the ground-state transition is revealed. When the external linear force presents, the occurrence of BOs excites the spin dynamics, and we reveal the chiral BOs and the accompanied spin dynamics of the system in different ground states. In particular, we further study the influence of periodically modulated linear force on BOs and spin dynamics. The frequencies of the linear force corresponding to the resonances and pseudoresonances are obtained analytically, which result in rich nonlinear dynamics. In resonances, stable and strong BOs (with larger amplitude) are observed. In pseudoresonances, because the pseudoresonance frequencies are related to the initial momentum and phase of the wave packet, a dispersion effect takes place and strong diffusion of wave packet occurs. When the frequency is nonresonant, drift and weak dispersion of wave packet occur simultaneously with the wave-packet oscillation. In all cases, the wave-packet dynamics is accompanied with periodic but anharmonic pseudospin oscillation. The BOs and spin dynamics are effectively controlled by periodically modulating the linear force.

5.
Psychiatry Res ; 315: 114697, 2022 09.
Artigo em Inglês | MEDLINE | ID: mdl-35839636

RESUMO

BACKGROUND: The neurobiology of the Major depressive disorder (MDD) with anxiety is still unclear. The present study aimed to explore the brain correlates of MDD with and without anxiety in men and women during resting-state fMRI. METHODS: Two hundred and fifty-four patients with MDD (MDD with anxiety, N = 152) and MDD without anxiety, N = 102) and 228 healthy controls (HCs) participated in this study. We compared the fALFF(fractional amplitude of low-frequency fluctuations) and ReHo(regional homogeneity) of ACC(anterior cingulate cortex) and insula among these three groups. We also compared gender difference between MDD with anxiety and MDD without anxiety. RESULTS: We found that the fALFF values within the ACC and insula were significantly lower in MDD with anxiety compared to without anxiety and HCs. However, we did not find differences in ReHo values among the three groups. In women, we found significant differences in fALFF values between MDD with and without anxiety. These differences were not observed in men. CONCLUSIONS: It is possible that MDD with anxiety show less spontaneous BOLD-fMRI signal intensity within the ACC and insula compared to MDD without anxiety, especially in women. The fALFF within the ACC and insula can be a potential biomarker for severe MDD phenotype.


Assuntos
Transtorno Depressivo Maior , Ansiedade/diagnóstico por imagem , Encéfalo/diagnóstico por imagem , Mapeamento Encefálico , Transtorno Depressivo Maior/complicações , Transtorno Depressivo Maior/diagnóstico por imagem , Feminino , Giro do Cíngulo/diagnóstico por imagem , Humanos , Imageamento por Ressonância Magnética
6.
Phys Rev E ; 104(3-1): 034214, 2021 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-34654141

RESUMO

We analytically and numerically study the different types of solitary wave in the two-component helicoidal spin-orbit coupled Bose-Einstein condensates (BECs). Adopting the multiscale perturbation method, we derive the analytical bright and dark solitary wave solutions of the system, and the stationary and moving bright (dark) solitary waves are obtained. The effects of spin-orbit coupling, the helicoidal gauge potential, the momentum, the Zeeman splitting, and the atomic interactions on the solitary wave types are discussed, and it is found that the coupling of these physical parameters can manipulate different types of solitary waves in the system. The results indicate that the helicoidal gauge potential breaks the symmetric properties of the energy band of the system and adjusts the energy band structure, thus further effecting the solitary wave properties, i.e., stationary or moving solitary wave, bright, or dark solitary wave. Correspondingly, the analytical predictions for exciting stationary or moving bright (dark) solitary wave in parameter space are obtained. In particular, the helicoidal gauge potential changes the solitary wave types drastically for the weak spin-orbit coupling, i.e., in the absence of the helicoidal gauge potential, only dark (bright) solitary wave solutions exist in the system with repulsive (attractive) atomic interaction; however, in the presence of the helicoidal gauge potential, both dark and bright solitary waves can exist in the system regardless of whether the atomic interaction is repulsive or attractive. In addition, we investigate the stability of solitary waves and obtain the stability regions of different types of solitary waves by applying the linear stability analysis. The dynamic evolution results of the solitary waves by the direct numerical simulation not only validate the linear stability analysis but also confirm the analytical prediction of the solitary waves. Finally, the collision effects between solitary waves are also presented by the numerical simulation. It is shown that the interactions between solitary waves in the system have both elastic and inelastic collisions, which are closely related to the position of solitary wave states in the linear energy band. Our results provide a potential way to adjust the types of solitary waves in BECs with helicoidal gauge potential.

7.
Phys Rev E ; 104(2-1): 024212, 2021 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-34525534

RESUMO

The stability and superfluidity of the Bose-Einstein condensate in two-leg ladder with magnetic field are studied. The dispersion relation and the phase diagram of the system are obtained. Three phases are revealed: the Meissner phase, the biased ladder (BL) phase, and the vortex phase. The dispersion relation and phase transition of the system strongly depend on the magnitude of atomic interaction strength, the rung-to-leg coupling ratio and the magnetic flux. Particularly, the change of the energy band structure in the phase transition region is modified significantly by the atomic interaction strength. Furthermore, based on the Bogoliubov theory, the energetic and dynamical stability of the system are invested. The stability phase diagram in the full parameter space is presented, and the dependence of superfluidity on the dispersion relation is illustrated explicitly. The atomic interaction strength can produce dynamical instability in the energetic unstable region and can expand the superfluid region. The results show that the stability of the system can be controlled by the atomic interaction strength, the rung-to-leg coupling ratio and the magnetic flux. In addition, the excitation spectrums in the Meissner phase, BL phase and vortex phase are further studied. The modulation of the excitation spectrum and the energetic stability of the system by the atomic interaction strength, the rung-to-leg coupling ratio and magnetic flux is discussed. Finally, through the numerical simulation, the dynamical instability of the system is verified by the time evolution of the Bloch wave and rung current. This provides a theoretical basis for controlling the superfluidity of the system.

8.
Artigo em Inglês | MEDLINE | ID: mdl-34119573

RESUMO

OBJECTIVE: While gastrointestinal (GI) symptoms are very common in patients with major depressive disorder (MDD), few studies have investigated the neural basis behind these symptoms. In this study, we sought to elucidate the neural basis of GI symptoms in MDD patients by analyzing the changes in regional gray matter volume (GMV) and gray matter density (GMD) in brain structure. METHOD: Subjects were recruited from 13 clinical centers and categorized into three groups, each of which is based on the presence or absence of GI symptoms: the GI symptoms group (MDD patients with at least one GI symptom), the non-GI symptoms group (MDD patients without any GI symptoms), and the healthy control group (HCs). Structural magnetic resonance images (MRI) were collected of 335 patients in the GI symptoms group, 149 patients in the non-GI symptoms group, and 446 patients in the healthy control group. The 17-item Hamilton Depression Rating Scale (HAMD-17) was administered to all patients. Correlation analysis and logistic regression analysis were used to determine if there was a correlation between the altered brain regions and the clinical symptoms. RESULTS: There were significantly higher HAMD-17 scores in the GI symptoms group than that of the non-GI symptoms group (P < 0.001). Both GMV and GMD were significant different among the three groups for the bilateral superior temporal gyrus, bilateral middle temporal gyrus, left lingual gyrus, bilateral caudate nucleus, right Fusiform gyrus and bilateral Thalamus (GRF correction, cluster-P < 0.01, voxel-P < 0.001). Compared to the HC group, the GI symptoms group demonstrated increased GMV and GMD in the bilateral superior temporal gyrus, and the non-GI symptoms group demonstrated an increased GMV and GMD in the right superior temporal gyrus, right fusiform gyrus and decreased GMV in the right Caudate nucleus (GRF correction, cluster-P < 0.01, voxel-P < 0.001). Compared to the non-GI symptoms group, the GI symptoms group demonstrated significantly increased GMV and GMD in the bilateral thalamus, as well as decreased GMV in the bilateral superior temporal gyrus and bilateral insula lobe (GRF correction, cluster-P < 0.01, voxel-P < 0.001). While these changed brain areas had significantly association with GI symptoms (P < 0.001), they were not correlated with depressive symptoms (P > 0.05). Risk factors for gastrointestinal symptoms in MDD patients (p < 0.05) included age, increased GMD in the right thalamus, and decreased GMV in the bilateral superior temporal gyrus and left Insula lobe. CONCLUSION: MDD patients with GI symptoms have more severe depressive symptoms. MDD patients with GI symptoms exhibited larger GMV and GMD in the bilateral thalamus, and smaller GMV in the bilateral superior temporal gyrus and bilateral insula lobe that were correlated with GI symptoms, and some of them and age may contribute to the presence of GI symptoms in MDD patients.


Assuntos
Transtorno Depressivo Maior/patologia , Substância Cinzenta/patologia , Dor Abdominal/etiologia , Dor Abdominal/psicologia , Adulto , Encéfalo/patologia , Escalas de Graduação Psiquiátrica Breve , Núcleo Caudado/patologia , Feminino , Humanos , Processamento de Imagem Assistida por Computador , Imageamento por Ressonância Magnética , Masculino , Lobo Temporal/patologia , Tálamo/patologia
9.
Phys Rev E ; 103(2-1): 022204, 2021 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-33736056

RESUMO

We theoretically study the ground-state phases and superfluidity of tunable spin-orbit-coupled Bose-Einstein condensates (BECs) under the periodic driving of Raman coupling. An effective time-independent Floquet Hamiltonian is proposed by using a high-frequency approximation, and we find single-particle dispersion, spin-orbit-coupling, and asymmetrical nonlinear two-body interaction can be modulated effectively by the periodic driving. The critical Raman coupling characterizing the phase transition and relevant physical quantities in three different phases (the stripe phase, plane-wave phase, and zero momentum phase) are obtained analytically. Our results indicate that the boundary of ground-state phases can be controlled and the system will undergo three different phase transitions by adjusting the external driving. Interestingly, we find the contrast of the stripe density can be enhanced by the periodic driving in the stripe phase. We also study the superfluidity of tunable spin-orbit-coupled BECs and find the dynamical instability can be tuned by the periodic driving of Raman coupling. Furthermore, the sound velocity of the ground-state and superfluidity state can be controlled effectively by tuning the periodic driving strength. Our results indicate that the periodic driving of Raman coupling provides a powerful tool to manipulate the ground-state phase transition and dynamical instability of spin-orbit-coupled BECs.

10.
Phys Rev E ; 104(6-1): 064215, 2021 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-35030834

RESUMO

We analytically and numerically discuss the dynamics of two pseudospin components Bose-Einstein condensates (BECs) with spin-orbit coupling (SOC) in deep optical lattices. Rich localized phenomena, such as breathers, solitons, self-trapping, and diffusion, are revealed and strongly depend on the strength of the atomic interaction, SOC, Raman detuning, and the spin polarization (i.e., the initial population difference of atoms between the two pseudospin components of BECs). The critical conditions for the transition of localized states are derived analytically. Based on the critical conditions, the detailed dynamical phase diagram describing the different dynamical regimes is derived. When the Raman detuning satisfies a critical condition, localized states with a fixed initial spin polarization can be observed. When the critical condition is not satisfied, we use two quenching methods, i.e., suddenly and linearly quenching Raman detuning from the soliton or breather state, to discuss the spin dynamics, phase transition, and wave packet dynamics by numerical simulation. The sudden quenching results in a damped oscillation of spin polarization and transforms the system to a new polarized state. Interestingly, the linear quenching of Raman detuning induces a controllable phase transition from an unpolarized phase to an expected polarized phase, while the soliton or breather dynamics is maintained.

11.
Phys Rev E ; 102(3-1): 032220, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-33076041

RESUMO

The Bose-Einstein condensates in a finite depth potential well provide an ideal platform to study the quantum escape dynamics. In this paper, the ground state, tunneling, and diffusion dynamics of the spin-orbit coupling (SOC) of Bose-Einstein condensates with two pseudospin components in a shallow trap are studied analytically and numerically. The phase transition between the plane-wave phase and zero-momentum phase of the ground state is obtained. Furthermore, the stability of the ground state is discussed, and the stability diagram in the parameter space is provided. The bound state (in which condensates are stably trapped in the potential well), the quasibound state (in which condensates tunnel through the well), and the unstable state (in which diffusion occurs) are revealed. We find that the finite depth potential well has an important effect on the phase transition of the ground state, and, interestingly, SOC can stabilize the system against the diffusion and manipulate the tunneling and diffusion dynamics. In particular, spatial anisotropic tunneling and diffusion dynamics of the two pseudospin components induced by SOC in quasibound and unstable states are observed. We provide an effective model and method to study and control the quantum tunneling and diffusion dynamics.

12.
Phys Rev E ; 100(3-1): 032220, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31639894

RESUMO

We theoretically study the modulation instability (MI) of the two-component helicoidal spin-orbit coupled Bose-Einstein condensates (BECs). The effects of spin-orbit coupling, the helicoidal gauge potential, and atomic interactions on MI are investigated. The results indicate that the presence of the helicoidal gauge potential breaks the symmetric properties of MI, strongly modifies the distribution of the MI region and the MI gain in parameters space, and the MI can be excited even when the miscibility condition for the atomic interactions is satisfied. Furthermore, the effect of the helicoidal gauge potential on MI is strongly coupled with the intra and intercomponent atomic interactions. Particularly, with the increase of the helical gauge potential, the MI gain increases for the repulsive atomic interaction case, however, the MI gain decreases for the attractive atomic interaction case. The direct numerical simulations are performed to support the analytical predictions, and a good agreement is found. Our results provide a potential way to manipulate the MI in BECs with helicoidal gauge potential.

13.
Nanotechnology ; 28(44): 445702, 2017 Nov 03.
Artigo em Inglês | MEDLINE | ID: mdl-28825405

RESUMO

Lots of two-dimensional (2D) materials have been predicted theoretically and further confirmed in experiments, and have wide applications in nanoscale electronic, optoelectronic and thermoelectric devices. In this work, the thermoelectric properties of ATeI (A = Sb and Bi) monolayers are systematically investigated according to semiclassical Boltzmann transport theory. It is found that spin-orbit coupling (SOC) has an important effect on the electronic transport coefficients of p-type doping, but a negative influence on n-type doping. The room-temperature sheet thermal conductance is 14.2 [Formula: see text] for SbTeI and 12.6 [Formula: see text] for BiTeI, which is lower than that of most well-known 2D materials, such as the transition-metal dichalcogenide, group IV-VI, group VA and group IV monolayers. The very low sheet thermal conductance of ATeI (A = Sb and Bi) monolayers is mainly due to their small group velocities and short phonon lifetimes. The strongly polarized covalent bonds between A and Te or I atoms induce strong phonon anharmonicity, which gives rise to low lattice thermal conductivity. It is found that the high-frequency optical branches contribute significantly to the total thermal conductivity, which is obviously different from the usual picture, where there is little contribution from the optical branches. According to cumulative lattice thermal conductivity with respect to the phonon mean free path (MFP), it is difficult to further reduce the lattice thermal conductivity using nanostructures. Finally, the possible thermoelectric figure of merit ZT values of the ATeI (A = Sb and Bi) monolayers are calculated. It is found that p-type doping has much better thermoelectric properties than n-type doping. At room temperature, the peak ZT can reach 1.11 for SbTeI and 0.87 for BiTeI, respectively. These results make us believe that ATeI (A = Sb and Bi) monolayers may be potential 2D thermoelectric materials, which could stimulate further experimental work towards the synthesis of these monolayers.

14.
Phys Chem Chem Phys ; 19(22): 14520-14526, 2017 Jun 07.
Artigo em Inglês | MEDLINE | ID: mdl-28537286

RESUMO

Strain engineering is a very effective method to continuously tune the electronic, topological, optical and thermoelectric properties of materials. In this work, strain-dependent phonon transport of recently-fabricated antimonene (Sb monolayers) under biaxial strain is investigated using a combination of first-principles calculations and the linearized phonon Boltzmann equation within the single-mode relaxation time approximation (RTA). It is found that the ZA dispersion of antimonene with strain less than -1% gives imaginary frequencies, which suggests that compressive strain can induce structural instability. Experimentally, it is possible to enhance structural stability by tensile strain. The calculated results show that lattice thermal conductivity increases with strain increasing from -1% to 6%, and lattice thermal conductivity at 6% strain is 5.6 times larger than that at -1% strain at room temperature. It is interesting that lattice thermal conductivity is inversely proportional to the buckling parameter h in a considered strain range. Such a strain dependence of lattice thermal conductivity is attributed to enhanced phonon lifetimes caused by increased strain, while group velocities have a decreased effect on lattice thermal conductivity with increasing strain. It is found that acoustic branches dominate the lattice thermal conductivity over the full strain range. The cumulative room-temperature lattice thermal conductivity at -1% strain converges to a maximum with the phonon mean free path (MFP) at 50 nm, while that at 6% strain becomes as large as 44 µm, which suggests that strain can give rise to very strong size effects on lattice thermal conductivity in antimonene. Finally, the increased lattice thermal conductivity caused by increasing strain can be explained by a reduced polarized covalent bond, inducing weak phonon anharmonicity. These results may provide guidance on fabrication techniques of group-VA element (As, Sb, Bi) monolayers, and offer perspectives on tuning lattice thermal conductivity by the size and strain for applications of thermal management and thermoelectricity.

15.
J Nat Prod ; 80(6): 1734-1741, 2017 06 23.
Artigo em Inglês | MEDLINE | ID: mdl-28394604

RESUMO

An investigation of the potential neuroprotective natural product constituents of the rhizomes of Typhonium giganteum led to the isolation of two new cerebrosides, typhonosides E (1) and F (2), along with 11 known analogues (3-13). The structures of compounds 1 and 2 were elucidated by spectroscopic data interpretation. The activity of these compounds against glutamate-induced cell apoptosis was investigated in PC12 cells. All compounds exhibited such activity, which was related to the length of the fatty acyl chain. Among them, longan cerebroside II (11), with the longest fatty acyl chain, showed the most potent protective effect in PC12 cells from glutamate injury, with an EC50 value of 2.5 µM. Moreover, at the molecular level, longan cerebroside II (11) downregulated the expression of caspase-9, caspase-3, and Bax, upregulated the expression of Bcl-2, and decreased the level of cytosolic cytochrome c in a concentration-dependent manner.


Assuntos
Cerebrosídeos/isolamento & purificação , Cerebrosídeos/farmacologia , Fármacos Neuroprotetores/isolamento & purificação , Fármacos Neuroprotetores/farmacologia , Animais , Apoptose/efeitos dos fármacos , Caspase 3/metabolismo , Caspase 9/metabolismo , Cerebrosídeos/química , Citocromos c/metabolismo , Ácido Glutâmico/farmacologia , Estrutura Molecular , Fármacos Neuroprotetores/química , Células PC12 , Proteínas Proto-Oncogênicas c-bcl-2/metabolismo , Ratos , Rizoma/química , Sapindaceae , Transdução de Sinais/efeitos dos fármacos
16.
Bioorg Med Chem Lett ; 26(10): 2526-2530, 2016 05 15.
Artigo em Inglês | MEDLINE | ID: mdl-27038495

RESUMO

A series of new aryloxyacetamide derivatives 10a-s and 14a-m are designed and synthesized. Their protective activities against the glutamate-induced cell death were investigated in differentiated rat pheochromocytoma cells (PC12 cells). Most compounds exhibited neuroprotective effects, especially for 10m, 10r, 14b and 14c, which showed potential protection of PC12 cells at three doses (0.1, 1.0, 10µM). MTT assay, Hoechst 33342/PI double staining, and high content screening (HCS) revealed that pretreatment of the cells with 10m, 10r, 14b and 14c has significantly decreased the extent of cell apoptosis in a dose-dependent manner. The results of western blot analysis demonstrated these compounds suppressed apoptosis of glutamate-induced PC12 cells via caspase-3 pathway. These compounds can be lead compounds for further discovery of neuroprotective agents for treating cerebral ischemic stroke. Basic structure-activity relationships are also presented.


Assuntos
Fármacos Neuroprotetores/química , Fármacos Neuroprotetores/farmacologia , Relação Estrutura-Atividade , Acetamidas/química , Animais , Apoptose/efeitos dos fármacos , Diferenciação Celular/efeitos dos fármacos , Técnicas de Química Sintética , Avaliação Pré-Clínica de Medicamentos/métodos , Ácido Glutâmico/farmacologia , Ensaios de Triagem em Larga Escala , Fármacos Neuroprotetores/síntese química , Células PC12 , Ratos
17.
Phys Rev E ; 93(2): 022214, 2016 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-26986338

RESUMO

We study the collective dynamics of the spin-orbit coupled two pseudospin components of a Bose-Einstein condensate trapped in a quasi-one-dimensional harmonic potential, by using variational and directly numerical approach of binary mean-field Gross-Pitaevskii equations. The results show that, because of strong coupling of spin-orbit coupling (SOC), Rabi coupling, and atomic interaction, the collective dynamics of the system behave as complex characters. When the Rabi coupling is absent, the density profiles of the system preserve the Gauss type and the wave packets do harmonic oscillations. The amplitude of the collective oscillations increases with SOC. Furthermore, when the SOC strength increases, the dipole oscillations of the two pseudospin components undergo a transition from in-phase to out-of-phase oscillations. When the Rabi coupling present, there will exist a critical value of SOC strength (which depends on the Rabi coupling and atomic interaction). If the SOC strength is less than this critical value, the density profiles of the system can preserve the Gauss type and the wave packets do anharmonic (the frequency of dipole oscillations depends on SOC) oscillations synchronously (i.e., in-phase oscillations). However, if the SOC strength is larger than this critical value, the wave packets are dynamically fragmented and the stable dipole oscillations of the system can not exist. The collective dynamics of the system can be controlled by adjusting the atomic interaction, SOC, and Rabi-coupling strength.

18.
Artigo em Inglês | MEDLINE | ID: mdl-25090385

RESUMO

Wuhua three-yellow chicken is a native breed of Guangdong Province in China. The complete mitochondrial DNA (mtDNA) genome presented here was the first assemble of Wuhua three-yellow chicken, which was determined through the polymerase chain reaction-based method. The complete mitogenome was 16,784 bp in length, with the nucleotide composition of 30.29% for A, 23.75% for T, 32.48% for C and 13.48% for G, and exhibited the typical mitochondrial structure, including 2 rRNA genes, 13 protein-coding genes, 22 tRNA genes and a non-coding control region.


Assuntos
Galinhas/genética , DNA Mitocondrial/química , Genoma Mitocondrial , Animais , Composição de Bases , Sequência de Bases , Dados de Sequência Molecular , Fases de Leitura Aberta , RNA Ribossômico/genética , RNA de Transferência/genética
19.
Asian J Androl ; 18(1): 74-9, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-25966629

RESUMO

MiR-200a was shown to be upregulated in the corpus cavernosum (CC) of rats with aging-related erectile dysfunction (A-ED) in our previous study. Among its target genes, SIRT1 was also reported as a protective factor in erectile function by our groups previously. Thus, miR-200a might attenuate the erectile function in A-ED via SIRT1 inhibition. In the present study, three animal groups were included: aged rats with ED (group AE, n = 8), aged rats with normal erectile function (group AN, n = 8), and young rats as normal controls (group YN, n = 8). CCs from each group were collected for histological and molecular measurements to validate the dysregulation of miR-200a and SIRT1. After that, the cavernous endothelial cells (CECs) from CC of aged rats with normal erectile function were transfected with miR-200a in vitro. Then the expression of SIRT1 and molecules within the eNOS/NO/PKG pathway were measured to investigate whether the transfection could imitate the attenuated process of erectile function in the aged. As a result, miR-200a was upregulated while the SIRT1, the levels of eNOS and cGMP were all downregulated in the CCs from AE group. After transfection in vitro, the miR-200a was upregulated while the SIRT1 and levels of eNOS and cGMP were obviously downregulated. Finally, based on the results of our previous study, we further verify that up-regulation of miR-200a could participate in the mechanisms of A-ED via SIRT1 inhibition, and mainly attenuate endothelial function via influencing the eNOS/NO/PKGpathway.


Assuntos
Fatores Etários , Endotélio/fisiopatologia , Disfunção Erétil/genética , MicroRNAs/fisiologia , Sirtuína 1/antagonistas & inibidores , Regulação para Cima , Animais , Masculino , Ratos , Ratos Sprague-Dawley
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...