Ultrafast reconfigurable devices with high‐speed responses, high‐resolution capabilities, and ultracompact sizes will be essential for future real‐time terahertz imaging, chemical detection, ...nondestructive biosensing, and communication systems. Multifunctional terahertz metasurfaces with active, programmable controls have enabled conspicuous functionalities of subwavelength planar devices and components for manipulating electromagnetic (EM) waves such as beam focusing, polarization modification, generation of exotic EM modes, or multibeam scanning applications. However, active metasurface technologies for EM beam manipulation, capable of dynamical topology change, or induced‐phase reconfiguration are usually requiring various semiconductor‐based controlling elements (e.g., PN diodes and transistors), which are difficult to implement in the high‐frequency spectrum of terahertz waves. In this work, a coding metasurface is introduced integrating patterned GeTe phase‐change materials as command elements, which allows the optical control of terahertz wave propagation. The suggested metasurface design brings plentiful of remarkable functionalities through different coding patterns and is highly effective to control beam tilting, directivity, and splitting of terahertz beams. The proposed concepts of coding metasurfaces integrating optically active phase‐change materials are successfully confirmed by experimental demonstration and can be extended to more complex terahertz systems for imaging, tomography, sensing, and 6G communication applications.
An optical‐based coding metasurface is simulated and experimentally demonstrated for multifunctional control of terahertz waves. The proposed meta‐atoms integrating phase‐change material GeTe provide 1‐bit phase difference by optical control of GeTe's state. The optical irradiation of the metasurface through specific coding masks provides different distributions of meta‐atoms defining multibeam control of terahertz waves (beam tilting, directing, and splitting).
This paper presents a low-profile and wideband metamaterial-lens (metalens) antenna based on high-refractive-index metasurface. A novel three-layer nonresonant metamaterial unit cell is introduced ...and analyzed by the full-wave simulation tool. The proposed unit cell is a stacking configuration of four H-shaped lines realized by multiple microwave laminates. It can achieve a large refractive index variation range of 4.76 (from 1.5 to 6.26). In addition, two impedance matching layers based on the proposed unit cell are developed to provide better transmission for incident waves passing through the metalens antenna. The attractiveness of this new metalens antenna is its low-profile thickness of <inline-formula> <tex-math notation="LaTeX">0.26~\lambda _{0} </tex-math></inline-formula>, where <inline-formula> <tex-math notation="LaTeX">\lambda _{0} </tex-math></inline-formula> is the wavelength at 10 GHz. To validate the performance of the metalens antenna, a wideband stub-loaded horn antenna with stable radiation patterns in E- and H-planes is adopted as the feeding antenna source. The measured results demonstrate a wide impedance bandwidth of 66% (7.2-14.3 GHz) and a high aperture efficiency of up to 65%. Moreover, its sidelobe and cross-polarization levels are less than −17 and −25 dB across the entire bandwidth, respectively.
Cancer is currently one of the most important publichealth problems in the world. Pancreatic cancer is afatal disease with poor prognosis. As in most othercountries, the health burden of pancreatic ...cancer inChina is increasing, with annual mortality rates almostequal to incidence rates. The increasing trend ofpancreatic cancer incidence is more significant in therural areas than in the urban areas. Annual diagnosesand deaths of pancreatic cancer in China are nowbeyond the number of cases in the United States.GLOBOCAN 2012 estimates that cases in China accountfor 19.45% （65727/337872） of all newly diagnosedpancreatic cancer and 19.27% （63662/330391） ofall deaths from pancreatic cancer worldwide. Thepopulation＇s growing socioeconomic status contributesto the rapid increase of China＇s proportional contributionto global rates. Here, we present an overview of controlprograms for pancreatic cancer in China focusing onprevention, early diagnosis and treatment. In addition,we describe key epidemiological, demographic,and socioeconomic differences between China anddeveloped countries. Facts including no nationwidescreening program for pancreatic cancer, delay in earlydetection resulting in a late stage at presentation,lack of awareness of pancreatic cancer in the Chinesepopulation, and low investment compared with othercancer types by government have led to backwardnessin China＇s pancreatic cancer diagnosis and treatment.Finally, we suggest measures to improve healthoutcomes of pancreatic cancer patients in China.
We study a dynamic job assignment problem in queueing systems with one class of Poisson arrivals and K groups of heterogeneous servers. A scheduling policy prescribes the job assignment among servers ...in each group at every state n (number of jobs in the system). Our goal is to obtain the optimal policy to minimize the long‐run average cost, which involves the increasingly convex holding cost for jobs and the operating cost for working servers. This problem has wide application scenarios in operations management, such as job scheduling in manufacturing systems, packet routing in communication systems, and staffing in service systems. We prove that the optimal policy has monotone structures and quasi bang–bang control forms. Specifically, we discover that the optimal policy is governed by the marginal cost rate c − μG(n), where c is the operating cost rate, μ is the service rate, and G(n) is called the perturbation realization factor at state n. Under the condition of scale economies which can be guaranteed by any increasingly concave operating cost in μ, we prove that the optimal policy obeys a so‐called c/μ‐rule: Servers with a smaller c/μ should be occupied by jobs with higher priority. Optimality of multi‐threshold type policies is further proved when the c/μ‐rule is applied. Our c/μ‐rule in group‐server queues can be viewed as a counterpart of the famous cμ‐rule in polling queues, which both significantly reduce the complexity of optimization problems. By utilizing these optimality structures, we also develop computational‐efficient algorithms to determine the optimal policy numerically. Simulation experiments demonstrate the good scalability and robustness of the c/μ‐rule, which are important for managerial practice.
The economy of China is growing rapidly. With this overwhelming growth, the country is experiencing a higher level of carbon emissions. Amid this backdrop, China is under immense pressure to reduce ...carbon emissions up to a sustainable level. This study adapted 31 provincial panel data from 2007 to 2017 using factor analysis system SBM-undesirable model to calculate the agro-ecological output of each province respectively and used a carbon transfer network impact analysis panel to calculate ecological performance impacts. Results show that (1) overall agro-ecological efficiency in China shows an upward trend but regional differences are evident. The efficiency in the eastern region is higher than that in the central and western regions but the extent of informatization in the central region is higher than that in the western region. (2) Informatization will significantly promote agro-ecological efficiency. (3) Changes in agricultural planting structure, agricultural value-added per capita, employment of human capital in the agricultural sector, and agricultural scale management are also important factors affecting agro-ecological growth. (4) China’s amount of carbon transfer is growing year by year, and energy-intensive areas and heavy industry bases are undertaking carbon transfer from the eastern coastal regions; (5) Jiangsu, Henan, and Hebei (Hubei) have the highest centers between 2007 and 2012; (6) inter-provincial carbon transmission is concentrated mainly in the metal smelting and rolling processing industries as well as in the coal, heat, and supply industries.
Dietary fibre has beneficial effects on energy metabolism, and the majority of studies have focused on short-chain fatty acids produced by gut microbiota. Ginseng has been reported to aid in body ...weight management, however, its mechanism of action is not yet clear. In this study, we focused on the potential modulating effect of ginseng on gut microbiota, aiming to identify specific strains and their metabolites, especially long-chain fatty acids (LCFA), which mediate the anti-obesity effects of ginseng.
Db/db mice were gavaged with ginseng extract (GE) and the effects of GE on gut microbiota were evaluated using 16S rDNA-based high throughput sequencing. To confirm the candidate fatty acids, untargeted metabolomics analyses of the serum and medium samples were performed.
We demonstrated that GE can induce
, which can produce an unsaturated LCFA, myristoleic acid (MA). Our results indicate that
and its metabolite MA can reduce adiposity by brown adipose tissue (BAT) activation and beige fat formation. In addition, the gene of
encoding Acyl-CoA thioesterases (ACOTs) exhibited the biosynthetic potential to synthesise MA, as knockdown (KD) of the ACOT gene by CRISPR-dCas9 significantly reduced MA production. Furthermore, exogenous treatment with KD
could not reproduce the beneficial effects of wild type
, which work by augmenting the circulating MA levels.
Our results demonstrated that the gut microbiota-LCFA-BAT axis plays an important role in host metabolism, which may provide a strategic advantage for the next generation of anti-obesity drug development.
According to guidelines, endoscopic resection should only be performed for patients whose early gastric cancer invasion depth is within the mucosa or submucosa of the stomach regardless of lymph node ...involvement. The accurate prediction of invasion depth based on endoscopic images is crucial for screening patients for endoscopic resection. We constructed a convolutional neural network computer-aided detection (CNN-CAD) system based on endoscopic images to determine invasion depth and screen patients for endoscopic resection.
Endoscopic images of gastric cancer tumors were obtained from the Endoscopy Center of Zhongshan Hospital. An artificial intelligence–based CNN-CAD system was developed through transfer learning leveraging a state-of-the-art pretrained CNN architecture, ResNet50. A total of 790 images served as a development dataset and another 203 images as a test dataset. We used the CNN-CAD system to determine the invasion depth of gastric cancer and evaluated the system’s classification accuracy by calculating its sensitivity, specificity, and area under the receiver operating characteristic curve.
The area under the receiver operating characteristic curve for the CNN-CAD system was .94 (95% confidence interval CI, .90-.97). At a threshold value of .5, sensitivity was 76.47%, and specificity 95.56%. Overall accuracy was 89.16%. Positive and negative predictive values were 89.66% and 88.97%, respectively. The CNN-CAD system achieved significantly higher accuracy (by 17.25%; 95% CI, 11.63-22.59) and specificity (by 32.21%; 95% CI, 26.78-37.44) than human endoscopists.
We constructed a CNN-CAD system to determine the invasion depth of gastric cancer with high accuracy and specificity. This system distinguished early gastric cancer from deeper submucosal invasion and minimized overestimation of invasion depth, which could reduce unnecessary gastrectomy.
Recently, artificial intelligence research has driven the development of stretchable and flexible electronic systems. Conductive hydrogels are a class of soft electronic materials that have emerging ...applications in wearable and implantable biomedical devices. However, current conductive hydrogels possess fundamental limitations in terms of their antibacterial performance and a mechanical mismatch with human tissues, which severely limits their applications in biological interfaces. Here, inspired by animal skin, a conductive hydrogel is fabricated from a supramolecular assembly of polydopamine decorated silver nanoparticles (PDA@Ag NPs), polyaniline, and polyvinyl alcohol, namely PDA@Ag NPs/CPHs. The resultant hydrogel has many desirable features, such as tunable mechanical and electrochemical properties, eye‐catching processability, good self‐healing ability as well as repeatable adhesiveness. Remarkably, PDA@Ag NPs/CPHs exhibit broad antibacterial activity against Gram‐negative and Gram‐positive bacteria. The potential application of this versatile hydrogel is demonstrated by monitoring large‐scale movements of the human body in real time. In addition, PDA@Ag NPs/CPHs have a significant therapeutic effect on diabetic foot wounds by promoting angiogenesis, accelerating collagen deposition, inhibiting bacterial growth, and controlling wound infection. To the best of the authors' knowledge, this is the first time that conductive hydrogels with antibacterial ability are developed for use as epidermal sensors and diabetic foot wound dressing.
Inspired by the multiple functions of animal skin, a conductive hydrogel is fabricated based on a supramolecular assembly of polydopamine decorated silver nanoparticles (PDA@Ag NPs), polyaniline, and polyvinyl alcohol, namely PDA@Ag NPs/CPHs. The resultant hydrogel has many desirable features, such as tunable mechanical and electrochemical properties, eye‐catching processability, good self‐healing ability as well as repeatable adhesiveness.
Understanding the Verwey transition in magnetite (Fe3O4), a strongly correlated magnetic oxide, is a one‐century‐old topic that recaptures great attention because of the recent spectroscopy studies ...revealing its orbital details. Here, the modulation of the Verwey transition by tuning the orbital configurations with ionic gating is reported. In epitaxial magnetite thin films, the insulating Verwey state can be tuned continuously to be metallic showing that the low‐temperature trimeron states can be controllably metalized by both the gate‐induced oxygen vacancies and proton doping. The ionic gating can also reverse the sign of the anomalous Hall coefficient, indicating that the metallization is associated with the presence of a new type of carrier with competing spin. The variable spin orientation associated with the sign reversal is originated from the structural distortions driven by the gate‐induced oxygen vacancies.
Ionic gating can suppress the Verwey state in magnetite (Fe3O4) by metalizing the trimeron insulating state with gated‐induced proton addition and oxygen vacancy. Tuning the trimeron state also causes the sign reversal in the anomalous Hall effect, indicating that the ionic gating can create a new type of carrier carrying competing spins.
We analyzed the number of circulating tumor cells (CTCs) and Epstein–Barr virus DNA (EBV DNA) for diagnosis, monitoring and prognosis of patients with metastatic nasopharyngeal carcinoma (mNPC). The ...levels of CTCs and EBV DNA were measured at baseline and after first‐line chemotherapy in 148 mNPC patients prospectively enrolled between December 2014 and August 2016. We also collected 122 non‐mNPC cases within the same time frame for examining CTCs and EBV DNA at baseline. In 270 NPC patients, we observed improved specificity (86.0% vs. 41.0%) and inferior sensitivity (42.3% vs. 81.3%) of CTCs as compared to EBV DNA for diagnosis of distant metastasis. mNPC patients were stratified into unfavorable and favorable prognostic groups, respectively, based on CTC of 12 at baseline and 1 after first‐line chemotherapy and EBV DNA of 10,000 at baseline and 4,000 after first‐line chemotherapy. Conversion of baseline unfavorable CTCs and EBV DNA to favorable after first‐line chemotherapy was associated with significantly longer progression‐free survival (PFS) and overall survival (OS) compared to patients with unfavorable CTCs and EBV DNA at both time points. Among patients with a complete/partial response as per imaging evaluation, favorable CTCs and EBV DNA levels after first‐line chemotherapy were associated with significantly longer PFS and OS. In conclusion, our data demonstrated the number of CTCs and EBV DNA before, after and during first‐line chemotherapy were strong predictive markers for mNPC patients. When utilized in conjunction with imaging studies, CTCs and EBV DNA could provide additional prognostic information.
What's new?
Endemic nasopharyngeal carcinoma (NPC) is associated with latent infection of the oncogenic Epstein‐Barr virus (EBV) and frequently metastasizes to distant lymph nodes and organs. Metastatic NPC is treated by serial administration of cytotoxic or targeted therapies and treatment response is generally assessed with serial imaging, which often fails to detect changes in tumor burden. Here, the authors show that the number of circulating tumor cells (CTCs) and EBV DNA levels before, after, and during first‐line chemotherapy are strong predictive markers for mNPC patients. When utilized in conjunction with imaging studies, CTCs and EBV DNA could provide additional prognostic information.
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