Quantum Light Generation Based on GaN Microring toward Fully On-Chip Source.

An integrated quantum light source is increasingly desirable in large-scale quantum information processing. Despite recent remarkable advances, a new material platform is constantly being explored for the fully on-chip integration of quantum light generation, active and passive manipulation, and detection. Here, for the first time, we demonstrate a gallium nitride (GaN) microring based quantum light generation in the telecom C-band, which has potential toward the monolithic integration of quantum light source. In our demonstration, the GaN microring has a free spectral range of 330 GHz and a near-zero anomalous dispersion region of over 100 nm. The generation of energy-time entangled photon pair is demonstrated with a typical raw two-photon interference visibility of 95.5±6.5%, which is further configured to generate a heralded single photon with a typical heralded second-order autocorrelation g_{H}^{(2)}(0) of 0.045±0.001. Our results pave the way for developing a chip-scale quantum photonic circuit.

Independent Manipulations of Transmitting and Receiving Channels by Nonreciprocal Programmable Metasurface.

The electromagnetic (EM) beam manipulations such as spatial scanning have always been the focus in information science and technology. Generally, the transmitting and receiving (T/R) beams of the same aperture should be coincident due to the reciprocal theory, and hence, more flexible controls of the spatial information are limited accordingly. Here, we propose a new approach to achieve independent controls of beam scanning in spatial T/R channels based on one aperture made by a nonreciprocal programmable metasurface. The meta-atom is designed to have independent propagation chains for T/R waves by introducing dual-direction power amplifiers (PAs) as the isolators for one-way transparency. A programmable phase shifter with a 360° coverage is loaded with the PA device in the transmitting or receiving chain to realize independent beam scanning in the T/R channels. A prototype of the proposed metasurface is fabricated, and independent beam scanning in the T/R channels is directly acquired with good performance in our measurements. In addition, a proof of concept of integrated sensing and auxiliary communications is accomplished to verify the validity of the presented method.

The Role of Water Molecules on Polaron Behavior at Rutile (110) Surface: A Constrained Density Functional Theory Study.

Understanding the behavior of a polaron in contact with water is of significant importance for many photocatalytic applications. We investigated the influence of water on the localization and transport properties of polarons at the rutile (110) surface by constrained density functional theory. An excess electron at a dry surface favors the formation of a small polaron at the subsurface Ti site, with a preferred transport direction along the [001] axis. As the surface is covered by water, the preferred spatial localization of the polarons is moved from the subsurface to the surface. When the water coverage exceeds half a monolayer, the preferred direction of polaron hopping is changed to the [110] direction toward the surface. This characteristic behavior is related to the Ti3d-orbital occupations and crystal field splitting induced by different distorted structures under water coverage. Our work describes the reduced sites that might eventually play a role in photocatalysis for rutile (110) surfaces in a water environment.

Inverse design of metasurfaces with customized transmission characteristics of frequency band based on generative adversarial networks.

In recent years, deep learning (DL) has demonstrated significant potential in the inverse design of metasurfaces, and the generation of metasurfaces with customized transmission characteristics of frequency band remains a challenging and underexplored area. In this study, we propose a DL-assisted method for the inverse design of transmissive metasurfaces. The method consists of a generative adversarial network (GAN)-based graph generator, an electromagnetic response predictor, and a genetic algorithm optimizer. By integrating these components, we can obtain customized metasurfaces with desired transmission characteristics of frequency band. We demonstrate the effectiveness of the proposed method through examples of inverse-designed three-layer cascaded transmissive metasurfaces with wideband, dual-band, and stopband responses in the 8∼12 GHz frequency range. Specifically, we realize three different types of dual-band metasurfaces, namely double-wide, front-wide and rear-narrow, and front-narrow and rear-wide configurations. Additionally, we analyze the accuracy and reliability of the inverse design method by employing data from the training dataset, self-defined objectives, and bandwidth-reduced target responses scaled from the wideband type as design inputs. Quantitative evaluation is performed using metrics such as mean absolute error and average precision. The proposed method successfully achieves the desired effect as intended.

Simultaneous manipulation of spatial fundamental and harmonic electromagnetic waves by microwave nonlinear metasurfaces.

In the area of manipulating the spatial electromagnetic (EM) waves fields, the metasurfaces have become much more attractive and powerful in recent years. Here, we propose a design to realize the simultaneous control of spatial fundamental and harmonic EM waves applying nonlinear metasurfaces in microwave band. The proposed meta-atom composed of three topological layers which are transmitting antenna, nonlinear wave guiding and receiving antenna respectively. And the critical factor of generating the harmonic is the nonlinear chip which is integrated into the middle layer. The microstrip power divider and phase shifter in each meta-atom are preciously tailored to actualize the spatial control of the fundamental and harmonic transmission beams in the far field. One prototype of the nonlinear metasurfaces is fabricated and corresponding radiation patterns of fundamental and harmonic modes are observed very well in the experience that can verify the validity of our proposed method.

Noncontact Electromagnetic Wireless Recognition for Prosthesis Based on Intelligent Metasurface.

With the development of artificial intelligence and Internet of Things, hand gesture recognition techniques have attracted great attention owing to their excellent applications in developing human-machine interaction (HMI). Here, the authors propose a non-contact hand gesture recognition method based on intelligent metasurface. Owing to the advantage of dynamically controlling the electromagnetic (EM) focusing in the wavefront engineering, a transmissive programmable metasurface is presented to illuminate the forearm with more focusing spots and obtain comprehensive echo data, which can be processed under the machine learning technology to reach the non-contact gesture recognition with high accuracy. Compared with the traditional passive antennas, unique variations of echo coefficients resulted from near fields perturbed by finger and wrist agonist muscles can be aquired through the programmable metasurface by switching the positions of EM focusing. The authors realize the gesture recognition using support vector machine algorithm based on five individual focusing spots data and all-five-spot data. The influences of the focusing spots on the gesture recognition are analyzed through linear discriminant analysis algorithm and Fisher score. Experimental verifications prove that the proposed metasurface-based non-contact wireless design can realize the classification of hand gesture recognition with higher accuracy than traditional passive antennas, and give an HMI solution.

Feasibility and preliminary experience of single-incision plus one-port laparoscopic total gastrectomy with Overlap esophagojejunostomy for gastric cancer: A study of 10 cases.

Background: This study aimed to explore the feasibility and safety of single-incision plus one-port laparoscopic total gastrectomy (SITG + 1) with Overlap esophagojejunostomy (SITG + 1-Overlap) and to share preliminary experiences. Methods: This retrospective study included 10 patients with gastric cancer located in the cardia or body who underwent SITG + 1-Overlap between August 2020 and October 2021.The demographics, tumor characteristics, postoperative outcomes, and short-term complications of all the enrolled patients were summarized and statistically analyzed. Data were expressed as mean ± standard deviation (SD) if they were normally distributed. Otherwise, Median (Quartile1, Quartile3) was used. Results: In the collective perioperative data of these 10 patients who underwent radical gastrectomy, the median of the length of transumbilical incision and blood loss were 3.0 cm and 100.0 ml respectively, and the mean operation time and 385.5 ± 51.6 min. Postoperative data indicated that the gastric tube was removed on 2.0 (2.0, 3.0) days, and the timing of first feeding, activity, flatus, and defecation was 1.5 (1.0, 2.0) days, 2.0 (2.0, 2.0) days, 3.0 (2.0, 3.0) days, and 3.8 ± 0.6 days, respectively. The timing of drainage tube removal was 4.6 ± 1.0 days after operation. The duration of hospital stay was 7.5 ± 1.2 days and the VAS pain scores for the 3 days following surgery were 3.0 (2.0, 3.3), 2.0 (2.0, 3.0), and 1.5 (1.0, 2.0) respectively. The mean number of retrieved lymph nodes was 30.7 ± 13.2. Most biochemical indicators gradually normalized with the recovery of the patients after surgery. No 30-day postoperative complications were noted. Conclusions: For the first time, our preliminary data indicate the feasibility and safety of Overlap esophagojejunostomy in SITG + 1 surgery. This modified Overlap procedure has the potential to simplify the reconstruction procedure and lower the technical challenge of SITG + 1 radical gastrectomy for cardia or upper gastric cancer in the early and advanced stages.

Single-incision plus one-port laparoscopic gastrectomy versus conventional multi-port laparoscopy-assisted gastrectomy for gastric cancer: a retrospective study.

BACKGROUND: We compared short-term perioperative outcomes after single-incision plus one-port laparoscopic gastrectomy (SILG+1) and conventional multi-port laparoscopy-assisted gastrectomy (C-LAG) for gastric cancer. METHODS: The work was conducted between August 2017 and October 2019. A total of 90 patients with early or advanced gastric cancer were retrospectively analyzed: 43 patients of which underwent SILG+1, and 47 of which underwent C-LAG, respectively. These were divided into two groups: the total gastrectomy group (SILT+1 and C-LATG) and the distal gastrectomy group (SILD + 1 and C-LADG). The demographics, tumor characteristics, postoperative outcomes, and short-term complications of all enrolled patients were summarized and statistically analyzed. RESULTS: The mean incision length in SILT+1 group was 5.40 cm shorter than that in C-LATG group (3.15 ± 0.43 vs. 8.55 ± 2.72, P < 0.001). This comparison between the SILD + 1 and the C-LADG group produced comparable results. The SILT+1 group underwent a 56.32 min longer operation than the C-LATG group (273.03 ± 66.80 vs. 216.71 ± 82.61, P = 0.0205). SILG+1 group had better postoperative visual analog scale (VAS) and cosmetic score than those of the C-LATG group (P < 0.05). There were no significant differences in preoperative demographics or 30-day postoperative complication rates between the SILG+1 and C-LAG groups. Tumor-related index, including mass size, histological type, number of retrieved lymph nodes, pathological tumor-node-metastasis (TNM) stage, and proximal and distal edges were all equivalent between the SILG+1 and the C-LAG group. CONCLUSIONS: This retrospective study demonstrates the safety and feasibility of SILG+1 with D1+ or D2 lymphadenectomy for the treatment of early and advanced gastric cancers, compared with C-LAG.

High-Efficiency Spatial-Wave Frequency Multiplication Using Strongly Nonlinear Metasurface.

In the past decades, metasurfaces have opened up a promising venue for manipulating lights and electromagnetic (EM) waves. In the field of nonlinearity, second-harmonic generation (SHG) is a research focus due to its diverse applications. There have been many researches for realizing SHG in optical regime using nonlinear characteristics of optical materials, but its efficiency is low. In microwave frequencies, SHGs are basically studied in the guided-wave systems. Here, high-efficiency SHGs of spatial waves are presented in the microwave frequency using nonlinear metasurface loaded with active chips at the subwavelength scale. The nonlinear meta-atom is composed of receiving antenna, transmitting antenna, and active circuit of frequency multiplier, which can realize strongly nonlinear response and link the EM signals from the receiving to transmitting antennas. Correspondingly, to achieve the function of spatial-wave frequency multiplication, the working frequency of the transmitting antenna in the meta-atom should be twice as that of the receiving antenna, and hence the active chip is well matched to obtain the signal transforming with high efficiency. Good performance of the spatial-wave frequency multiplication is demonstrated in the proof-of-concept experiments with the best transform efficiency of 85.11% under normal incidence, validating the proposed method.

Wavelength-dependent holographic impedance metasurfaces.

Impedance metasurface can establish a link between an electromagnetic surface wave and spatial wave and hence has attracted much attention of researchers in recent years. The holographic method, which is well known in the optical area, has also the great ability to shape the radiated beams in the microwave band by introducing the concept of surface impedance. Here, we propose a method to shape the radiated beams at two different wavelengths using single-layer multiplexing holographic impedance metasurface with in-plane feeding. For one wavelength, the generated broadside beam in the far field has the left-hand circular polarization, while the broadside beam in the other wavelength has the right-hand circular polarization. The radiation performance under different wavelengths are controlled independently due to the novel design of two eigen-modes in the impedance unit cell, in which the ratio of the two wavelengths can be large enough. To verify the proposed design experimentally, we fabricate a metasurface sample, and good agreement is observed between the simulation and measurement results.

Leaky-Wave Radiations by Modulating Surface Impedance on Subwavelength Corrugated Metal Structures.

One-dimensional (1D) subwavelength corrugated metal structures has been described to support spoof surface plasmon polaritons (SPPs). Here we demonstrate that a periodically modulated 1D subwavelength corrugated metal structure can convert spoof SPPs to propagating waves. The structure is fed at the center through a slit with a connected waveguide on the input side. The subwavelength corrugated metal structure on the output surface is regarded as metasurface and modulated periodically to realize the leaky-wave radiation at the broadside. The surface impedance of the corrugated metal structure is modulated by using cosine function and triangle-wave function, respectively, to reach the radiation effect. Full wave simulations and measuremental results are presented to validate the proposed design.

Transmission-Type 2-Bit Programmable Metasurface for Single-Sensor and Single-Frequency Microwave Imaging.

The programmable and digital metamaterials or metasurfaces presented recently have huge potentials in designing real-time-controlled electromagnetic devices. Here, we propose the first transmission-type 2-bit programmable coding metasurface for single-sensor and single- frequency imaging in the microwave frequency. Compared with the existing single-sensor imagers composed of active spatial modulators with their units controlled independently, we introduce randomly programmable metasurface to transform the masks of modulators, in which their rows and columns are controlled simultaneously so that the complexity and cost of the imaging system can be reduced drastically. Different from the single-sensor approach using the frequency agility, the proposed imaging system makes use of variable modulators under single frequency, which can avoid the object dispersion. In order to realize the transmission-type 2-bit programmable metasurface, we propose a two-layer binary coding unit, which is convenient for changing the voltages in rows and columns to switch the diodes in the top and bottom layers, respectively. In our imaging measurements, we generate the random codes by computer to achieve different transmission patterns, which can support enough multiple modes to solve the inverse-scattering problem in the single-sensor imaging. Simple experimental results are presented in the microwave frequency, validating our new single-sensor and single-frequency imaging system.

Holographic leaky-wave metasurfaces for dual-sensor imaging.

Metasurfaces have huge potentials to develop new type imaging systems due to their abilities of controlling electromagnetic waves. Here, we propose a new method for dual-sensor imaging based on cross-like holographic leaky-wave metasurfaces which are composed of hybrid isotropic and anisotropic surface impedance textures. The holographic leaky-wave radiations are generated by special impedance modulations of surface waves excited by the sensor ports. For one independent sensor, the main leaky-wave radiation beam can be scanned by frequency in one-dimensional space, while the frequency scanning in the orthogonal spatial dimension is accomplished by the other sensor. Thus, for a probed object, the imaging plane can be illuminated adequately to obtain the two-dimensional backward scattered fields by the dual-sensor for reconstructing the object. The relativity of beams under different frequencies is very low due to the frequency-scanning beam performance rather than the random beam radiations operated by frequency, and the multi-illuminations with low relativity are very appropriate for multi-mode imaging method with high resolution and anti- noise. Good reconstruction results are given to validate the proposed imaging method.

Dual-channel near-field control by polarizations using isotropic and inhomogeneous metasurface.

We propose a method for dual-channel near-field manipulations by designing isotropic but inhomogeneous metasurfaces. As example, we present a dual-channel near-field focusing metasurface device. When the device is driven by surface waves from different channels on the metasurface, the near fields will be focused at the same spatial point with different polarizations. Conversely, if a linearly polarized source is radiated at the spatial focal point, different channels will be evoked on the metasurface controlled by polarization. We fabricated and measured the metasurface device in the microwave frequency. Well agreements between the simulation and measurement results are observed. The proposed method exhibits great flexibility in controlling the surface waves and spatial waves simultaneously. It is expected that the proposed method and dual-channel device will facilitate the manipulation of near electromagnetic or optical waves in different frequency regimes.

Generation of spatial Bessel beams using holographic metasurface.

We propose to use backward radiations of leaky waves supported by a holographic metasurface to produce spatial Bessel beams in the microwave frequency regime. The holographic metasurface consists of a grounded dielectric slab and a series of metal patches. By changing the size of metal patches, the surface-impedance distribution of the holographic metasurface can be modulated, and hence the radiation properties of the leaky waves can be designed to realize Bessel beams. Both numerical simulations and experiments verify the features of spatial Bessel beams, which may be useful in imaging applications or wireless power transmissions with the dynamic focal-depth controls.

Diffraction-free surface waves by metasurfaces.

We propose a method to design and realize planar Bessel lens using artificial metasurfaces to produce diffraction-free surface waves. The planar Bessel lens is composed of two sublenses: a half Maxwell fisheye lens which can shape the surface cylindrical waves to surface plane waves, and an inhomogeneous flat lens which can convert the surface plane waves into approximate diffraction-free surface waves in a diamond-shaped focusing area. Through the planar Bessel lens, a point source on the metasurface directly radiates the diffraction-free surface waves. In realization, we construct the inhomogeneous metasurfaces by subwavelength metallic patches printed on a grounded dielectric substrate. Simulation and experimental results have good agreements, which jointly show the formation of the diffraction-free surface waves in the microwave band.

Frequency-controls of electromagnetic multi-beam scanning by metasurfaces.

We propose a method to control electromagnetic (EM) radiations by holographic metasurfaces, including to producing multi-beam scanning in one dimension (1D) and two dimensions (2D) with the change of frequency. The metasurfaces are composed of subwavelength metallic patches on grounded dielectric substrate. We present a combined theory of holography and leaky wave to realize the multi-beam radiations by exciting the surface interference patterns, which are generated by interference between the excitation source and required radiation waves. As the frequency changes, we show that the main lobes of EM radiation beams could accomplish 1D or 2D scans regularly by using the proposed holographic metasurfaces shaped with different interference patterns. This is the first time to realize 2D scans of antennas by changing the frequency. Full-wave simulations and experimental results validate the proposed theory and confirm the corresponding physical phenomena.

[Randomized controlled clinical trials of individualized treatment of cerebral palsy children by warm-reinforcing needling combined with Bobath rehabilitation training].

OBJECTIVE: To observe the effect of warm-reinforcing needling combined with modern rehabilitation training on motor function of cerebral palsy (CP) children. METHODS: Sixty cases of CP children were randomly divided into acupuncture combined with rehabilitation (Acu + Rehab, n = 30) group and Rehab (n = 30) group. Patients of the Acu + Rehab group were treated by warm-reinforcing needling stimulation of Jiaji (EX-B 2), Jianyu (LI 15), Quchi (LI 11), Hegu (LI 4), Zusanli (ST 36), Yinlingquan (GB 34), Sanyinjiao (SP 6), Juegu (GB 39), Yanglingquan (GB 34), etc., combined with Bobath rehabilitation therapy, and those of the Rehab group treated by Bobath rehabilitation (stimulating key control points in the body, triggering reflexes that provide head and body control). The treatment was conducted every day,with three months being a therapeutic course,two courses in all. The Peabody Developmental Motor Scales 2 (PDMS-2) was used to evaluate the CP children's motor function [1) gross motor: posture (straightness ratio), locomotion and object manipulation; 2) fine motor: grasping and visual-Motor integration]. RESULTS: After the treatment, of the 30 and 30 cases in the Acu+ Rehab and Rehab groups, 1 (3.33%) and 0 (0%) were cured, 20 (66.67%) and 18 (60.00%) experienced marked improvement, 9 (30.00%) and 12 (40.00%) were invalid, with the effective rates being 70.00% and 60.00% respectively. The therapeutic effect of the Acu + Rehab group was markedly superior to that of the Rehab group (P < 0.05). After 6 months ' treatment, the scores of posture, locomotor, object manipulation and grasping, and visual-movement integration were significantly increased in comparison with pre-treatment in the same one group (P < 0.05), and the effects of the Acu + Rehab group were obviously superior to those of Rehab group in increasing the scores of posture, locomotor, object manipulation and grasping after 6 months' treatment (P < 0.05). CONCLUSION: Warm-reinforcing needling combined with Bobath rehabilitation has a better therapeutic effect in improving gross motor and fine motor functions of CP children.

[Effects of warming-reinforcing acupuncture combined with rehabilitation training on the early motor function of hemiparalysis patients caused by ischemic brain stroke: a randomized and controlled study].

OBJECTIVE: To verify the improvement function of warming-reinforcing acupuncture combined with rehabilitation training on the early motor function of hemiparalysis patients caused by ischemic brain stroke. METHODS: Eighty cases were randomly divided into a warming-reinforcing acupuncture combined with rehabilitation training group (group A) and a rehabilitation training group (group B), 40 cases in each group. Both groups were treated with internal routine treatment. The Motor Relearning Program rehabilitation was used in group B, while warming-reinforcing acupuncture combined with Motor Relearning Program rehabilitation were used in group A. Jianyu (LI 15), Quchi (LI 11), Hegu (LI 4), Yanglingquan (GB 34), Yinlingquan (SP 9), Zusanli (ST 36), Sanyinjiao (SP 6) were selected, and warming-reinforcing method was used in these points, they were treated for 3 weeks. The neurological functional deficits scores of hemiparalysis patients, Fugl-Meyer Score, Motor Function Assessment Score (MAS), Barthel Index and Mini-mental State Examination (MMSE) were used to evaluate the condition of hemiparalysis patients before and after treatment. RESULTS: The effective rate of group A (87.5%, 35/40) superior to that of group B (67.5%, 27/40) (P < 0.05). The neurological functional deficit scores, Fugl-Meyer score, MAS and Barthel Index of both groups were improved after treatment (P < 0.01, P < 0.05), and the improved degree of group A was better than that of group B (P < 0.01, P < 0.05). CONCLUSION: There is obvious improvement function of warming-reinforcing acupuncture combined with rehabilitation training on the early motor function of hemiparalysis patients caused by ischemic brain stroke, and the function is better than that of simple rehabilitation training.

[Effect of Qingdu Suppository-containing serum on cervical carcinoma SiHa cell MDM2 gene expression].

OBJECTIVE: To investigate the effect and mechanism of Qingdu Suppository (QDS) in suppressing the growth of SiHa cell of cervical carcinoma on the cytobiologic and molecular biologic level. METHODS: SiHa cells were cultured in media with serum containing different concentrations of QDS and blank serum, as well as serum containing various Chinese herbal or Western drugs as positive control. SiHa cell growth and proliferation was determined by MTT assay, the cell cycle and apoptosis were analyzed by flow cytometry technique, and the expression of proto-oncogene MDM2 detected semi-quantitatively by RT-PCR. RESULTS: The amount of cells decreased after cultured with drug-containing serum 8% in concentration, with the highest inhibitory effect shown by drug-containing serum after acting for 72 h, which was significantly different to that in the control group (P < 0.01). Among the various time phases of cell cycle, the percentage of cells in S phase was significantly decreased. Drug-containing serum showed somewhat effect on cell apoptosis, but no obvious regularity could be found. RT-PCR showed significant decrease of MDM2 expression. CONCLUSION: QDS containing serum could not only directly suppress the growth of cervical carcinoma cells, but also inhibit the tumor by the molecular mechanism of down-regulating MDM2 gene expression.