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1.
Appl Opt ; 60(24): 7069-7079, 2021 Aug 20.
Artigo em Inglês | MEDLINE | ID: mdl-34612990

RESUMO

An illumination design problem can be transformed into an optimal mass transport problem based on ray mapping. To construct a freeform surface that best fits the normal field, an efficient numerical method is put forward in this paper. In this method, the normal vectors are constructed by two adjacent orthogonal tangent vectors at each point, and then the normal vectors are substituted into Snell's law to obtain nonlinear equations describing the surface coordinates. Finally, the continuous and accurate freeform surface can be obtained by solving these nonlinear equations. The simulation results show that the proposed method not only provides lower relative standard deviation, but also significantly reduces the normal deviation more than the traditional one. It can be seen from the comparison results that different numerical integrations of a non-integrable normal field calculated by optimal mass transport can lead to different results, and the proposed method is more feasible than the traditional one, especially in the off-axis case. The simulation results of the illumination effect of some complex patterns also show that the freeform surface constructed by this method can restore the target pattern efficiently and control the normal vector error in a low range.

2.
Nat Commun ; 12(1): 4902, 2021 08 12.
Artigo em Inglês | MEDLINE | ID: mdl-34385461

RESUMO

Efficient and precise base editors (BEs) for C-to-G transversion are highly desirable. However, the sequence context affecting editing outcome largely remains unclear. Here we report engineered C-to-G BEs of high efficiency and fidelity, with the sequence context predictable via machine-learning methods. By changing the species origin and relative position of uracil-DNA glycosylase and deaminase, together with codon optimization, we obtain optimized C-to-G BEs (OPTI-CGBEs) for efficient C-to-G transversion. The motif preference of OPTI-CGBEs for editing 100 endogenous sites is determined in HEK293T cells. Using a sgRNA library comprising 41,388 sequences, we develop a deep-learning model that accurately predicts the OPTI-CGBE editing outcome for targeted sites with specific sequence context. These OPTI-CGBEs are further shown to be capable of efficient base editing in mouse embryos for generating Tyr-edited offspring. Thus, these engineered CGBEs are useful for efficient and precise base editing, with outcome predictable based on sequence context of targeted sites.


Assuntos
Sistemas CRISPR-Cas , Citidina Desaminase/metabolismo , Edição de Genes/métodos , Aprendizado de Máquina , Uracila-DNA Glicosidase/metabolismo , Animais , Sequência de Bases , Sítios de Ligação/genética , Caenorhabditis elegans/genética , Códon/genética , Citidina Desaminase/genética , Escherichia coli/genética , Feminino , Biblioteca Gênica , Células HEK293 , Humanos , Camundongos , Reprodutibilidade dos Testes , Uracila-DNA Glicosidase/genética
3.
Sensors (Basel) ; 21(13)2021 Jun 30.
Artigo em Inglês | MEDLINE | ID: mdl-34208935

RESUMO

This paper proposes and implements a lightweight, "real-time" localization system (SORLA) with artificial landmarks (reflectors), which only uses LiDAR data for the laser odometer compensation in the case of high-speed or sharp-turning. Theoretically, due to the feature-matching mechanism of the LiDAR, locations of multiple reflectors and the reflector layout are not limited by geometrical relation. A series of algorithms is implemented to find and track the features of the environment, such as the reflector localization method, the motion compensation technique, and the reflector matching optimization algorithm. The reflector extraction algorithm is used to identify the reflector candidates and estimates the precise center locations of the reflectors from 2D LiDAR data. The motion compensation algorithm predicts the potential velocity, location, and angle of the robot without odometer errors. Finally, the matching optimization algorithm searches the reflector combinations for the best matching score, which ensures that the correct reflector combination could be found during the high-speed movement and fast turning. All those mechanisms guarantee the algorithm's precision and robustness in the high speed and noisy background. Our experimental results show that the SORLA algorithm has an average localization error of 6.45 mm at a speed of 0.4 m/s, and 9.87 mm at 4.2 m/s, and still works well with the angular velocity of 1.4 rad/s at a sharp turn. The recovery mechanism in the algorithm could handle the failure cases of reflector occlusion, and the long-term stability test of 72 h firmly proves the algorithm's robustness. This work shows that the strategy used in the SORLA algorithm is feasible for industry-level navigation with high precision and a promising alternative solution for SLAM.


Assuntos
Robótica , Algoritmos , Movimento (Física) , Movimento
4.
Opt Lett ; 45(9): 2538-2541, 2020 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-32356810

RESUMO

The self-imaging of periodic light patterns, also known as the Talbot effect, is usually limited to periods that are larger than the wavelength. Here we present, theoretically and experimentally, a method to overcome this limitation by using superoscillating light patterns. The input intensity distribution is a periodic band-limited function with relatively large periods, but it contains regions of multilobe periodic oscillations with periods that are smaller than half of the wavelength. We observe the revival of the input pattern, including the subwavelength superoscillating regions, at large distances of more than 40 times the optical wavelength. Moreover, at fractional Talbot distances, we observe even faster local oscillations, with periods of approximately one-third of the optical wavelength.

6.
Medicine (Baltimore) ; 99(17): e19761, 2020 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-32332614

RESUMO

The objective of this review is to systematically evaluate the short-term efficacy of mud therapy in the treatment of knee osteoarthritis (KOA).Randomized controlled trials, in which treatment of KOA is mud therapy, were included by systematically searching the PubMed, Embase, and the Cochrane Library databases.According to inclusion criteria and searching method, 11 articles, containing a total of 1106 patients, were included in the study. Our results showed significant differences in visual analog scale pain score and Western Ontario and McMaster Universities Osteoarthritis Index (pain, stiffness, function). In addition, the heterogeneity of study included is lower (I < 25%).According to the results of this meta-analysis, mud therapy can effectively alleviate the pain and improve joint function for KOA.


Assuntos
Terapia por Lama/normas , Osteoartrite do Joelho/terapia , Fatores de Tempo , Humanos , Terapia por Lama/métodos , Osteoartrite do Joelho/psicologia , Resultado do Tratamento
7.
Medicine (Baltimore) ; 99(9): e19211, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-32118722

RESUMO

BACKGROUND: To assess the efficacy and safety of plaster splint vs splints in the treatment of distal radius fractures (DRFs). METHODS: For a more comprehensive collection of original study, we mainly searched 9 electronic databases including the PubMed, Web of Science, EMBASE, Cochrane Library, Cochrane Central Register of Controlled Trials (CENTRAL), Clinical Trials.gov, the Chinese National Knowledge Infrastructure Database (CNKI), Wanfang Database, and VIP Database. The retrieval date of all databases is from the establishment to January 2019. In the aspect of assessing the quality of original research methodology, we mainly rely on the Cochrane risk bias assessment tool and GRADE assessment method. Revman 5.3 is used for statistical analysis. RESULTS: A total of 8 studies involving 717 participants were included. The results showed that effective rate (RR = 0.99, 95%CI 0.91 to 1.07, P = .83), reduction rate (RR = 1.00, 95%CI 0.93 to 1.07, P = .98), and complication rate of the plaster splint had no significant difference with the splint. In addition, for the excellent rate of treatment, subgroup analysis based on the included studies found that when the intervention period was 4 weeks, the plaster splint was better than the splint, and when the intervention period was more than 4 weeks, there was no significant difference between them. CONCLUSIONS: There is no sufficient evidence that plaster splint is superior to splint. However, according to current evidence, plaster splint is more effective than splint when the intervention period is shorter (4 weeks), and its advantage disappears when the intervention period is longer (> 4 weeks). It should be noted that the results of this study were influenced by the sample size and the quality of the included studies. More high-quality and well-controlled RCTs are needed to draw better conclusions in further study.


Assuntos
Fraturas do Rádio/terapia , Contenções , Humanos , Ensaios Clínicos Controlados Aleatórios como Assunto , Resultado do Tratamento
8.
Phys Rev Lett ; 123(13): 133901, 2019 Sep 27.
Artigo em Inglês | MEDLINE | ID: mdl-31697515

RESUMO

We consider a binary bosonic condensate with weak mean-field (MF) residual repulsion, loaded in an array of nearly one-dimensional traps coupled by transverse hopping. With the MF force balanced by the effectively one-dimensional attraction, induced in each trap by the Lee-Hung-Yang correction (produced by quantum fluctuations around the MF state), stable on-site- and intersite-centered semidiscrete quantum droplets (QDs) emerge in the array, as fundamental ones and self-trapped vortices, with winding numbers, at least, up to five, in both tightly bound and quasicontinuum forms. The application of a relatively strong trapping potential leads to squeezing transitions, which increase the number of sites in fundamental QDs and eventually replace vortex modes by fundamental or dipole ones. The results provide the first realization of stable semidiscrete vortex QDs, including ones with multiple vorticity.

9.
Medicine (Baltimore) ; 98(31): e16562, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31374022

RESUMO

BACKGROUND: Distal radius fractures (DRFs) is one of the most common bone injuries in children, which may lead to deformity and other complications if the treatment is not prompt or appropriate. Splints external fixation is a common conservative treatment for such fractures. Therefore, we conducted a systematic review and meta-analysis to explore the efficacy, safety and cost benefits of splints in the treatment of DRFs in children. METHODS: PubMed, Web of Science, Embase, Cochrane Library, Cochrane Central Register of Controlled Trials (CENTRAL), and ClinicalTrials.gov, Chinese National Knowledge Infrastructure Database (CNKI), Wanfang Database, and VIP Database were searched for eligible randomized controlled trials (RCTs). The methodological quality of the included studies and the level of evidence for results were assessed, respectively, using the risk bias assessment tool of Cochrane and the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) method. Statistical analysis was conducted with Revman 5.3. RESULTS: This study will analyze and integrate the existing evidence for effectiveness, safety and cost benefits of splints on DRFs in children. CONCLUSION: The conclusion of this study will provide evidence to effectiveness, safety and cost benefits of splints on DRFs in children, which can further guide the selection of appropriate interventions. PROSPERO REGISTRATION NUMBER: CRD42019123429.


Assuntos
Fraturas do Rádio/terapia , Contenções/efeitos adversos , Contenções/normas , Adolescente , Criança , Pré-Escolar , Humanos , Segurança do Paciente/normas , Pediatria/instrumentação , Pediatria/métodos , Fraturas do Rádio/economia , Contenções/economia
10.
Medicine (Baltimore) ; 98(32): e16707, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31393375

RESUMO

BACKGROUND: Dislocation of shoulder joint is the most prone to occurrence in all joints of human body, which is common in young people and has a high recurrence rate. It is mainly treated by conservative treatment. External rotation and internal rotation fixation are 2 common conservative therapies in clinical practice. Therefore, we conduct this systematic review and meta-analysis to evaluate the efficacy and safety of the 2 treatments. METHODS: Nine electronic databases, PubMed, Web of Science, Embase, Cochrane Library, Cochrane Central Register of Controlled Trials (CENTRAL), and ClinicalTrials.gov, CNKI, Wanfang Database and VIP Database, will be searched to find and include randomized controlled trials that meet inclusion criteria. RevMan5.3 will be used for data analysis and synthesis in this study. Subgroup analysis and sensitivity analysis will also be performed if necessary. In addition, GRADE will be used in the evaluation of evidence hierarchy. RESULTS: This study will analyze and integrate the original evidence so far for clinical efficacy and safety of immobilization in external rotation and internal rotation on shoulder dislocation. CONCLUSION: The conclusion of this study will conclude higher evidence and suggestions for the treatment of shoulder dislocation, so as to further guide clinical decision making. PROSPERO REGISTRATION NUMBER: CRD42018106030.


Assuntos
Imobilização/métodos , Amplitude de Movimento Articular/fisiologia , Luxação do Ombro/terapia , Tratamento Conservador/métodos , Humanos , Metanálise como Assunto , Revisões Sistemáticas como Assunto
11.
Phys Rev Lett ; 123(24): 243904, 2019 Dec 13.
Artigo em Inglês | MEDLINE | ID: mdl-31922837

RESUMO

The optical Hall effect manifests itself as angular momentum separation induced by the photonic spin-orbit interaction. Such a celebrated Hall effect, at the mercy of the angular momentum conservation law, has attracted tremendous interest owing to its science and potential applications in precision measurements, material characterizations, and photonic devices, as well as quantum optics. However, to date, the Hall effect only expresses angular momentum separation of the spin term (spin-spin separation) or the orbital term (orbit-orbit separation), whereas the spin-orbit angular momentum separation, named as the spin-orbit Hall effect, remains unexplored. Here we demonstrate for the first time that this spin-orbit effect could appear when the polarization state of the light beam evolves adiabatically from the equator toward the poles of the higher-order Poincaré sphere, rather than the conventional Poincaré sphere. In this scenario, the intrinsic spin and orbital components of the light beam become separated, leading to equal nonzero spin and orbital angular momenta in magnitude but with the opposite sign. We further show that the spin-orbit Hall effect can be controlled via crystal birefringence and hence holds promise for applications; e.g., it is shown that the separated orbital angular momentum could be utilized in particle manipulations.

12.
Philos Trans A Math Phys Eng Sci ; 376(2124)2018 Jul 28.
Artigo em Inglês | MEDLINE | ID: mdl-29891496

RESUMO

We introduce a one-dimensional [Formula: see text]-symmetric system, which includes the cubic self-focusing, a double-well potential in the form of an infinitely deep potential box split in the middle by a delta-functional barrier of an effective height ε, and constant linear gain and loss, γ, in each half-box. The system may be readily realized in microwave photonics. Using numerical methods, we construct [Formula: see text]-symmetric and antisymmetric modes, which represent, respectively, the system's ground state and first excited state, and identify their stability. Their instability mainly leads to blowup, except for the case of ε=0, when an unstable symmetric mode transforms into a weakly oscillating breather, and an unstable antisymmetric mode relaxes into a stable symmetric one. At ε>0, the stability area is much larger for the [Formula: see text]-antisymmetric state than for its symmetric counterpart. The stability areas shrink with increase of the total power, P In the linear limit, which corresponds to [Formula: see text], the stability boundary is found in an analytical form. The stability area of the antisymmetric state originally expands with the growth of γ, and then disappears at a critical value of γThis article is part of the theme issue 'Dissipative structures in matter out of equilibrium: from chemistry, photonics and biology (part 1)'.

13.
Sci Rep ; 8(1): 3618, 2018 02 26.
Artigo em Inglês | MEDLINE | ID: mdl-29483594

RESUMO

We proposed an innovative method to achieve dynamic control of particle separation by employing viscoelastic fluids in deterministic lateral displacement (DLD) arrays. The effects of shear-thinning and elasticity of working fluids on the critical separation size in DLD arrays are investigated. It is observed that each effect can lead to the variation of the critical separation size by approximately 40%. Since the elasticity strength of the fluid is related to the shear rate, the dynamic control can for the first time be easily realized through tuning the flow rate in microchannels.

14.
Opt Express ; 25(15): 17589-17599, 2017 Jul 24.
Artigo em Inglês | MEDLINE | ID: mdl-28789251

RESUMO

We demonstrate numerically the ability for directionally releasing the stored ultrashort light pulse from a microcavity by means of two-pulse nonlinear interaction in a cascading Bragg grating structure. The setting is built by a chirped grating segment which is linked through a uniform segment, including a tunable microcavity located at the junction between the two components. Our simulations show that stable trapping of an ultrashort light pulse can be achieved in the setting. The stored light pulse in a microcavity can be possibly released, by nonlinearly interacting with the lateral incident control pulse. Importantly, by breaking the symmetry of potential cavity, the stably trapped light pulse can be successfully released from the microcavity to the expected direction. Owing to the induced optical nonlinearity, the released ultrashort light pulses could preserve their shapes, propagating in a form of Bragg grating solitons through the uniform component, which is in contrast to the extensively studied light pulse trappings in photonic crystal cavities which operate at the linear regime.

15.
Phys Rev Lett ; 118(14): 144501, 2017 Apr 07.
Artigo em Inglês | MEDLINE | ID: mdl-28430474

RESUMO

We report on the theoretical and experimental study of the generation of propagating waveguide modes on the water surface. These propagating modes are modulated in the transverse direction in a manner that satisfies boundary conditions on the walls of the water tank. It is shown that the propagating modes possess both anomalous and normal dispersion regimes, in contrast to the extensively studied zero mode that, in the case of deep water, only has normal dispersion with a fixed frequency independent dispersion coefficient. Importantly, by using a carrier frequency at which the group velocity dispersion crosses zero, a linear nonspreading and shape-preserving wave packet is observed. By increasing the wave steepness, nonlinear effects become pronounced, thereby enabling the first observation of linearly chirped parabolic water wave pulses in the anomalous dispersion regime. This parabolic wave maintains its linear frequency chirp and does not experience wave breaking during propagation.

16.
Phys Rev E ; 95(3-1): 032226, 2017 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-28415205

RESUMO

We consider a dipolar Bose-Einstein condensate trapped in an array of two-well systems with an arbitrary orientation of the dipoles relative to the system's axis. The system can be built as a chain of local traps sliced into two parallel lattices by a repelling laser sheet. It is modeled by a pair of coupled discrete Gross-Pitaevskii equations, with dipole-dipole self-interactions and cross interactions. When the dipoles are not polarized perpendicular or parallel to the lattice, the cross interaction is asymmetric, replacing the familiar symmetric two-component discrete solitons by two new species of cross-symmetric ones, viz., on-site- and off-site-centered solitons, which are strongly affected by the orientation of the dipoles and separation between the parallel lattices. A very narrow region of intermediate asymmetric discrete solitons is found at the boundary between the on- and off-site families. Two different types of solitons in the PT-symmetric version of the system are constructed too, and stability areas are identified for them.

17.
Opt Express ; 24(12): 13210-9, 2016 Jun 13.
Artigo em Inglês | MEDLINE | ID: mdl-27410338

RESUMO

Anderson localization has been observed in various types of waves, such as matter waves, optical waves and acoustic waves. Here we reveal that the effect of Anderson localization can be also induced in metallic nonlinear nanoparticle arrays excited by a random electrically driving field. We find that the dipole-induced nonlinearity results in ballistic expansion of dipole intensity during evolution; while the randomness of the external driving field can suppress such an expansion. Increasing the strength of randomness above the threshold value, a localized pattern of dipole intensity can be generated in the metallic nanoparticle arrays. By means of statistics, the mean intensity distribution of the dipoles reveals the formation of Anderson localization. We further show that the generated Anderson localization is highly confined, with its size down to the scale of incident wavelength. The reported results might facilitate the manipulations of electromagnetic fields in the scale of wavelength.

18.
Opt Lett ; 40(11): 2572-5, 2015 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-26030560

RESUMO

All-optical soliton diode (AOSD) is proposed based on a sandwich nonlinear Bragg-grating structure: a linearly chirped Bragg-grating linked to a uniform Bragg-grating and again to a chirped Bragg-grating. The nonreciprocity is achieved by introducing two spatially asymmetric chirped Bragg-gratings with optical nonlinearity. High transmission ratio up to 150 is obtained when launching a picosecond Gaussian pulse into the setting. We find that such pulses in a form of solitons propagate at a rather small velocity (<0.03c) when pulse wavelength is selected in the vicinity of photonic bandgap.

19.
Opt Express ; 22(11): 13927-39, 2014 Jun 02.
Artigo em Inglês | MEDLINE | ID: mdl-24921584

RESUMO

Discrete fundamental and dipole solitons are constructed, in an exact analytical form, in an array of linear waveguides with an embedded PT-symmetric dimer, which is composed of two nonlinear waveguides carrying equal gain and loss. Fundamental solitons in tightly knit lattices, as well as all dipole modes, exist above a finite threshold value of the total power. However, the threshold vanishes for fundamental solitons in loosely knit lattices. The stability of the discrete solitons is investigated analytically by means of the Vakhitov-Kolokolov (VK) criterion, and, in the full form, via the computation of eigenvalues for perturbation modes. Fundamental and dipole solitons tend to be stable at smaller and larger values of the total power (norm), respectively. The increase of the strength of the coupling between the two defect-forming sites leads to strong expansion of the stability areas. The scattering problem for linear lattice waves impinging upon the defect is considered too.

20.
Opt Express ; 22(24): 29679-92, 2014 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-25606899

RESUMO

We introduce a 2D network built of PT-symmetric dimers with on-site cubic nonlinearity, the gain and loss elements of the dimers being linked by parallel square-shaped lattices. The system may be realized as a set of PT-symmetric dual-core waveguides embedded into a photonic crystal. The system supports PT-symmetric and antisymmetric fundamental solitons (FSs) and on-site-centered solitary vortices (OnVs). Stability of these discrete solitons is the central topic of the consideration. Their stability regions in the underlying parameter space are identified through the computation of stability eigenvalues, and verified by direct simulations. Symmetric FSs represent the system's ground state, being stable at lowest values of the power, while anti-symmetric FSs and OnVs are stable at higher powers. Symmetric OnVs, which are also stable at lower powers, are remarkably robust modes: on the contrary to other PT-symmetric states, unstable OnVs do not blow up, but spontaneously rebuild themselves into stable FSs.


Assuntos
Luz , Modelos Teóricos , Fatores de Tempo
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