A compact low-profile dual-band Circularly Polarized(CP)microstrip antenna is proposed for the Bei Dou Navigation Satellite System(BDS).To achieve dual-band functionality,a single-layer multimode design is employed,in...A compact low-profile dual-band Circularly Polarized(CP)microstrip antenna is proposed for the Bei Dou Navigation Satellite System(BDS).To achieve dual-band functionality,a single-layer multimode design is employed,incorporating F-,L-,and T-shaped slots at the corners for CP performance.Additionally,a Defected Ground Structure(DGS)is implemented to further enhance the antenna's efficiency.A detailed parameter analysis is conducted to optimize the antenna's size and performance balance.After optimization,the final dimensions of the antenna are minimized while still meeting the design requirements.The prototype of the optimized antenna is fabricated and tested,demonstrating coverage of frequency bands from 1.182 GHz to 1.217 GHz and 1.547 GHz to 1.569 GHz.The antenna effectively supports dual-band CP for B1I and B2b frequency bands.A performance metric,the Ratio of relative Bandwidth to Volume(RBV),is introduced to evaluate the antenna's efficiency.Compared to similar designs,the proposed antenna offers a smaller size without sacrificing performance,making it well-suited for BDS airborne applications.展开更多
BACKGROUND Rectal cancer is one of the common digestive system malignant tumors around the world.Its early diagnosis and staging are crucial for rectal cancer treatment and prognosis.In recent years,tumor markers have...BACKGROUND Rectal cancer is one of the common digestive system malignant tumors around the world.Its early diagnosis and staging are crucial for rectal cancer treatment and prognosis.In recent years,tumor markers have gradually received attention in early screening,treatment monitoring and prognostic evaluation of cancer,but their predictive role in rectal cancer staging and differentiation is still unclear.AIM To assess the prognostic value of tumor markers alpha-fetoprotein(AFP)cancer antigen 72-4(CA72-4),carbohydrate antigen 19-9(CA19-9),and carcinoembryonic antigen(CEA),alongside multimodal magnetic resonance imaging(MRI),for staging and differentiating rectal cancer in patients.METHODS This study retrospectively analyzed 167 patients with rectal cancer who were treated at our institution from January 2020 to December 2024.Each patient underwent serological testing and multimodal MRI for diagnosis.Histopathological examination after surgical resection or imaging based on follow-up was used as the gold standard.According to the T stage and differentiation degree,patients were divided into low stage group(T1-T2)and high stage group(T3-T4).In addition,they were divided into low-differentiation groups and high-differentiation groups according to their differentiation degree.We compared the accuracy,sensitivity and specificity of tumor marker levels and MRI in rectal cancer stage and differentiation.RESULTS The study's findings indicate that in the context of rectal cancer T staging,there is substantial concordance between MRI and clinicopathological assessments,with a Kappa coefficient of 0.789(P<0.001).Similarly,for various degrees of tumor differentiation,MRI and clinicopathological evaluations demonstrated substantial agreement,with a Kappa coefficient of 0.651(P<0.001).Notably,the concentrations of tumor markers CA19-9,CA72-4,CEA,and AFP were significantly elevated in the T3-T4 stage compared to the T1-T2 stage.Furthermore,these markers were significantly higher in the low-differentiation group compared to the high-differentiation group(P<0.05).The combined use of tumor markers and MRI for preoperative T staging of rectal cancer yielded a diagnostic sensitivity of 93.7%and a specificity of 94.6%,as evidenced by the receiver operating characteristic analysis,with an area under the curve of 0.947.For tumor differentiation,the diagnostic sensitivity and specificity were 93.6%and 97.1%,respectively,with an area under the curve of 0.978(95%confidence interval:0.946-1.000),surpassing the accuracy of individual detection methods.CONCLUSION The CA19-9,CA72-4,CEA and AFP tumor markers combined with multimodal MRI have high sensitivity and specificity in diagnosing rectal cancer stage and differentiation.Their diagnostic efficacy is significantly better than that of single tests,which can effectively improve the predictive ability of rectal cancer stage and differentiation,provide a more reliable diagnostic reference for clinical practice,and have important clinical significance.展开更多
We propose a dual-polarized lens antenna system based on isotropic metasurfaces for 12 GHz applications. The metasurface lens is composed of subwavelength unit cells（0.24λ0） with metallic strips etched on the top a...We propose a dual-polarized lens antenna system based on isotropic metasurfaces for 12 GHz applications. The metasurface lens is composed of subwavelength unit cells（0.24λ0） with metallic strips etched on the top and bottom sides of the unit cell, and a cross-slots metallic layer in the middle that serves as the ground. The multimode resonance in the unit cell can realize a large phase shift（covering 0？–360？）, and the total transmission efficiency of the lens is above 80%.The feed antenna at the focal point of the lens is a broadband dual-polarized microstrip antenna. Both the simulated and the measured results demonstrate that the dual-polarized lens antenna system can realize a gain of more than 16.1 dB, and an input port isolation of more than 25.0 dB.展开更多
This study presents two multimode stepped-impedance structures to design single-and dual-band filters. Transmission zeroes are introduced for the single-band filter by using dual-mode stepped-impedance resonators. The...This study presents two multimode stepped-impedance structures to design single-and dual-band filters. Transmission zeroes are introduced for the single-band filter by using dual-mode stepped-impedance resonators. The single-band filter with high selectivity is centered at 6.02 GHz and has a fractional bandwidth （FBW） of 25.6%. Four stubs （two low frequency and two high frequency ones） are connected to the rectangular patch in the center to construct a quadruple-mode resonator. The independent conditions of the center frequencies of the high and low bands of the resonator are analyzed. A dual-band filter, which operates at 1.53 GHz and 2.44 GHz with FWBs of 12.1% and 14.1%, respectively is designed. The single-and dual-band filters are both fabricated with double-sided YBCO films and they can be used in mobile and satellite communications.展开更多
Accurate preoperative prediction of lymph node metastasis(LNM)in esophageal cancer(EC)patients is of crucial clinical significance for treatment planning and prognosis.AIM To develop a clinical radiomics nomogram that...Accurate preoperative prediction of lymph node metastasis(LNM)in esophageal cancer(EC)patients is of crucial clinical significance for treatment planning and prognosis.AIM To develop a clinical radiomics nomogram that can predict the preoperative lymph node(LN)status in EC patients.METHODS A total of 32 EC patients confirmed by clinical pathology(who underwent surgical treatment)were included.Real-time fluorescent quantitative reverse transcription-polymerase chain reaction was used to detect the expression of B7-H3 mRNA in EC tissue obtained during preoperative gastroscopy,and its correlation with LNM was analyzed.Radiomics features were extracted from multi-modal magnetic resonance imaging of EC using Pyradiomics in Python.Feature extraction,data dimensionality reduction,and feature selection were performed using XGBoost model and leave-one-out cross-validation.Multivariable logistic regression analysis was used to establish the prediction model,which included radiomics features,LN status from computed tomography(CT)reports,and B7-H3 mRNA expression,represented by a radiomics nomogram.Receiver operating characteristic area under the curve(AUC)and decision curve analysis(DCA)were used to evaluate the predictive performance and clinical application value of the model.RESULTS The relative expression of B7-H3 mRNA in EC patients with LNM was higher than in those without metastasis,and the difference was statistically significant(P<0.05).The AUC value in the receiver operating characteristic(ROC)curve was 0.718(95%CI:0.528-0.907),with a sensitivity of 0.733 and specificity of 0.706,indicating good diagnostic performance.The individualized clinical prediction nomogram included radiomics features,LN status from CT reports,and B7-H3 mRNA expression.The ROC curve demonstrated good diagnostic value,with an AUC value of 0.765(95%CI:0.598-0.931),sensitivity of 0.800,and specificity of 0.706.DCA indicated the practical value of the radiomics nomogram in clinical practice.CONCLUSION This study developed a radiomics nomogram that includes radiomics features,LN status from CT reports,and B7-H3 mRNA expression,enabling convenient preoperative individualized prediction of LNM in EC patients.展开更多
BACKGROUND A primary central nervous system lymphoma(PCNSL)presenting with massive hemorrhage is a rare occurrence that is difficult to distinguish from a high-grade glioblastoma.Comprehensive descriptions of the imag...BACKGROUND A primary central nervous system lymphoma(PCNSL)presenting with massive hemorrhage is a rare occurrence that is difficult to distinguish from a high-grade glioblastoma.Comprehensive descriptions of the imaging characteristics of such tumors have not yet been reported.Herein,we reported a case of a PCNSL with massive hemorrhage by presenting the imaging features of computed tomography(CT)imaging and structural and perfusion magnetic resonance imaging(MRI).CASE SUMMARY A 48-year-old man presented with headache lasting for 10 d.CT of the brain showed a round,heterogeneous,high-density lesion with surrounding edema in the right temporal lobe.For further diagnosis,a series of MRI examinations of the brain were subsequently performed,and a hemorrhagic lesion with ring-like enhancement was determined.The whole lesion was relatively hypoperfused on arterial spin labeling images.Surgical resection of the lesion and histopathological examination confirmed that the lesion was a diffuse large B-cell lymphoma with massive hemorrhage.CONCLUSION PCNSLs with hemorrhage occur very rarely,and structural and perfusion MRI examinations are requested exceedingly rarely.This case provided insight into some characteristics of a hemorrhagic lymphoma on CT and MRI examinations.Perfusion MRI examination may be useful for the differential diagnosis of PCNSLs and other brain tumors.展开更多
A dural arteriovenous fistula(DAVF) is an abnormal linkage connecting the arterial and venous systems within the intracranial dura mater. A basicranial emissary vein DAVF drains into the cavernous sinus and the ophtha...A dural arteriovenous fistula(DAVF) is an abnormal linkage connecting the arterial and venous systems within the intracranial dura mater. A basicranial emissary vein DAVF drains into the cavernous sinus and the ophthalmic vein, similar to a cavernous sinus DAVF. Precise preoperative identification of the DAVF location is a prerequisite for appropriate treatment. Treatment options include microsurgical disconnection, endovascular transarterial embolization(TAE), transvenous embolization(TVE), or a combination thereof. TVE is an increasingly popular approach for the treatment of DAVFs and the preferred approach for skull base locations, due to the risk of cranial neuropathy caused by dangerous anastomosis from arterial approaches. Multimodal magnetic resonance imaging(MRI) can provide anatomical and hemodynamic information for TVE. The therapeutic target must be precisely embolized in the emissary vein, which requires guidance via multimodal MRI. Here, we report a rare case of successful TVE for a basicranial emissary vein DAVF, utilizing multimodal MRI assistance. The fistula had vanished, pterygoid plexus drainage had improved, and the inferior petrosal sinus had recanalized, as observed on 8-month follow-up angiography. Symptoms and signs of double vision, caused by abduction deficiency, disappeared. Detailed anatomic and hemodynamic assessment by multimodal MRI is the key to guiding successful diagnosis and treatment.展开更多
Objective This study aims to explore the application value of multimodal magnetic resonance imaging(MRI)in the diagnosis of atypical hepatocellular carcinoma(HCC).Methods 80 patients with atypical HCC who were admitte...Objective This study aims to explore the application value of multimodal magnetic resonance imaging(MRI)in the diagnosis of atypical hepatocellular carcinoma(HCC).Methods 80 patients with atypical HCC who were admitted to our hospital from August 2018 to February 2020 were selected as the research subjects.All patients underwent dynamic computed tomography(CT)enhancement scans,and then multimodal MRI scans,including an MRI plain scan,dynamic contrastenhancement(DCE),and diffusion-weighted imaging(DWI).Then,the image data were analyzed.Results The diagnostic accuracy of the observation group(95.00%)was significantly higher than that of the control group(75.00%).This difference was statistically significant(χ2=6.128,P<0.05).With the increase of the b value,the apparent diffusion coefficient(ADC)values of the liver tissue and liver cancer tissue gradually decreased.Compared with normal liver tissue,the ADC value of liver cancer tissue was significantly lower than that of normal liver tissue(P<0.05).A plain MRI scan of 89 lesions,DCE examination of 93 lesions,(1)7 lesions were slow-rising and fast-falling;(2)72 lesions were fast-rising and fast-falling;(3)10 were platform-type lesions;(4)4 lesions had no enhancement.Conclusion The diagnostic efficiency of a multimodal MRI in the diagnosis of atypical HCC is high,and it has particular clinical application value.展开更多
Glioma survival risk prediction is of great significance for the individualized treatment and assessment programs.Currently,most deep learning based survival prediction paradigms rely on invasive and expensive histopa...Glioma survival risk prediction is of great significance for the individualized treatment and assessment programs.Currently,most deep learning based survival prediction paradigms rely on invasive and expensive histopathology and genomics methods.However,magnetic resonance imaging(MRI)has emerged as a promising non-invasive alternative with significant prognostic potential.To leverage the benefits of MRI,we propose a segmentation-guided fully automated multimodal MRI-based survival network(SGS-Net),which can simultaneously perform glioma segmentation and survival risk prediction.Specifically,the task interrelation is addressed using a hybrid convolutional neural network-Transformer(CNN-Transformer)encoder to represent the shared high-level semantic features by co-training a decoder for glioma segmentation and a Cox model for survival prediction.Then,to ensure the effective representation of the high-level features,glioma segmentation as an auxiliary task is utilized to guide survival prediction by jointly optimizing the segmentation loss and the Cox partial log-likelihood loss.Furthermore,a pair-wise ranking loss is designed to allow the network to learn the survival difference between patients.To balance the multi-task losses,an uncertain weight manner is adopted to adaptively adjust the weights for preventing task bias.Finally,the proposed SGS-Net is assessed using a publicly available multi-institutional dataset.Experimental and visual results show that SGS-Net achieves promising segmentation performance and obtains a C-index of 81.07%for survival risk prediction,which outperforms several existing state-of-the-art methods and even histopathology-based methods.In addition,Kaplan-Meier survival analysis confirms that the prognosis risk generated by SGS-Net is consistent with the prior prognosis based on the grading or genotyping paradigms.展开更多
During the past several decades,the multimode resonator(MMR)technique has been extensively investigated and widely used,with successful exploration of a variety of high-performance patch antennas,slot antennas,dielect...During the past several decades,the multimode resonator(MMR)technique has been extensively investigated and widely used,with successful exploration of a variety of high-performance patch antennas,slot antennas,dielectric resonant antennas,dipole antennas,and so on.In this review paper,we summarize the research milestones for these MMR antennas worldwide as one of the most contributive research teams in this field.First,the basic working principles of the MMR technique are clearly illustrated and studied,including mode excitation,mode suppression,impedance performance improvement,and radiation performance improvement.Next,the research topics regarding impedance performance enhancement,i.e.,widebandwidth operation,multibandwidth operation,and mutual coupling reduction,based on the MMR method are intensively described.After that,the relevant works on radiation performance enhancement,i.e.,high-gain,wide-beamwidth,multibeam,multipolarization,low-cross-polarization,filtering-response,and leaky-wave antennas,based on the MMR method are extensively illustrated.By using this technique,several ideas about operating frequency reallocation,electric-field null control,radiation pattern reshaping,and efficiency null generation of the antennas are proposed and demonstrated by our team for the first time.In addition,the application of the MMR technique for wireless communication systems is introduced and presented,such as implant communication,wireless power transfer,and multiple-input multiple-output communication.With these arrangements,exploration and reporting of more interesting and useful MMR design methods can be anticipated in the future.展开更多
The brain is a complex organ that requires precise mapping to understand its structure and function.Brain atlases provide a powerful tool for studying brain circuits,discovering biological markers for early diagnosis,...The brain is a complex organ that requires precise mapping to understand its structure and function.Brain atlases provide a powerful tool for studying brain circuits,discovering biological markers for early diagnosis,and developing personalized treatments for neuropsychiatric disorders.Neuromodulation techniques,such as transcranial magnetic stimulation and deep brain stimulation,have revolutionized clinical therapies for neuropsychiatric disorders.However,the lack of fine-scale brain atlases limits the precision and effectiveness of these techniques.Advances in neuroimaging and machine learning techniques have led to the emergence of stereotactic-assisted neurosurgery and navigation systems.Still,the individual variability among patients and the diversity of brain diseases make it necessary to develop personalized solutions.The article provides an overview of recent advances in individualized brain mapping and navigated neuromodulation and discusses the methodological profiles,advantages,disadvantages,and future trends of these techniques.The article concludes by posing open questions about the future development of individualized brain mapping and navigated neuromodulation.展开更多
Integrase strand transfer inhibitors(INSTIs)have emerged as the first‐line choice for treating human immunodeficiency virus(HIV)infection due to their superior efficacy and safety.However,the impact of INSTIs on the ...Integrase strand transfer inhibitors(INSTIs)have emerged as the first‐line choice for treating human immunodeficiency virus(HIV)infection due to their superior efficacy and safety.However,the impact of INSTIs on the development of neuropsychiatric conditions in people living with HIV(PLWH)is not fully understood due to limited data.In this study,we conducted a cross‐sectional examination of PLWH receiving antiretroviral therapy,with a specific focus on HIV‐positive men who have sex with men(MSM)on INSTI‐based regimens(n=61)and efavirenz(EFV)‐based regimens(n=28).Participants underwent comprehensive neuropsychiatric evaluations and multimodal magnetic resonance imaging(MRI)scans,including T1‐weighted images and resting‐state functional MRI.Compared to the EFV group,the INSTI group exhibited primarily reduced gray matter volume(GMV)in the right superior parietal gyrus,higher regional homogeneity(ReHo)in the left postcentral gyrus,lower ReHo in the right orbital part of the inferior frontal gyrus,and increased voxel‐wise functional connectivity for the seed region in the left inferior temporal gyrus with clusters in the right cuneus.Furthermore,the analysis revealed a main effect of antiretroviral drugs on GMV changes,but no main effect of neuropsychiatric disorders or their interaction.The repeated analysis of participants who did not switch regimens confirmed the GMV changes in the INSTI group,validating the initial findings.Our study demonstrated gray matter atrophy and functional brain changes in PLWH on INSTI‐based regimens compared to those on EFV‐based regimens.These neuroimaging results provide valuable insights into the characteristics of brain network modifications in PLWH receiving INSTI‐based regimens。展开更多
In this article,studies on the multimode excitation problem of waveguides and antennas,the balance/unbalance mech-anism and the balanced feeding techniques in dipole antenna systems are first briefly historically revi...In this article,studies on the multimode excitation problem of waveguides and antennas,the balance/unbalance mech-anism and the balanced feeding techniques in dipole antenna systems are first briefly historically reviewed.In this context,general-ized odd-even mode theory is advanced to quantitatively and approximately describe the mutual coupling effect between a feed line and an antenna.As is mathematically deduced and demonstrated,the modal parity mismatch between the feed line and the antenna should ultimately dominate the unbalance phenomenon in antenna systems.Thus,an elegant,closed-form formula is derived to ap-proximately calculate the“unbalance degree”of a straight dipole off-center fed by a symmetric twin-wire line.Design approaches for the simplest,linear,1-D multimode resonant antennas are introduced.Moreover,the“falling tone excitation”law gauged based on prototype dipoles is revealed and used to develop a mode synthesis design approach for microstrip patch antennas(MPAs)and 2-D sectorial electric dipole antennas.Design examples with distinctive radiation performance are presented and discussed.Finally,possible development trends of multimode resonant antennas are prospected.展开更多
Atomic layers of hexagonal boron nitride(h-BN)crystal are excellent candidates for structural materials as enabling ultrathin,two-dimensional(2D)nanoelectromechanical systems(NEMS)due to the outstanding mechanical pro...Atomic layers of hexagonal boron nitride(h-BN)crystal are excellent candidates for structural materials as enabling ultrathin,two-dimensional(2D)nanoelectromechanical systems(NEMS)due to the outstanding mechanical properties and very wide bandgap(5.9 eV)of h-BN.In this work,we report the experimental demonstration of h-BN 2D nanomechanical resonators vibrating at high and very high frequencies(from~5 to~70 MHz),and investigations of the elastic properties of h-BN by measuring the multimode resonant behavior of these devices.First,we demonstrate a dry-transferred doubly clamped h-BN membrane with~6.7 nm thickness,the thinnest h-BN resonator known to date.In addition,we fabricate circular drumhead h-BN resonators with thicknesses ranging from~9 to 292 nm,from which we measure up to eight resonance modes in the range of~18 to 35 MHz.Combining measurements and modeling of the rich multimode resonances,we resolve h-BN’s elastic behavior,including the transition from membrane to disk regime,with built-in tension ranging from 0.02 to 2 N m−1.The Young’s modulus of h-BN is determined to be EY≈392 GPa from the measured resonances.The ultrasensitive measurements further reveal subtle structural characteristics and mechanical properties of the suspended h-BN diaphragms,including anisotropic built-in tension and bulging,thus suggesting guidelines on how these effects can be exploited for engineering multimode resonant functions in 2D NEMS transducers.展开更多
基金co-supported by the Natural Science Foundation of Tianjin,China(No.21JCZDJC00860)the Civil Aviation Security Capacity Building Funding Project,China(No.2020[142])。
文摘A compact low-profile dual-band Circularly Polarized(CP)microstrip antenna is proposed for the Bei Dou Navigation Satellite System(BDS).To achieve dual-band functionality,a single-layer multimode design is employed,incorporating F-,L-,and T-shaped slots at the corners for CP performance.Additionally,a Defected Ground Structure(DGS)is implemented to further enhance the antenna's efficiency.A detailed parameter analysis is conducted to optimize the antenna's size and performance balance.After optimization,the final dimensions of the antenna are minimized while still meeting the design requirements.The prototype of the optimized antenna is fabricated and tested,demonstrating coverage of frequency bands from 1.182 GHz to 1.217 GHz and 1.547 GHz to 1.569 GHz.The antenna effectively supports dual-band CP for B1I and B2b frequency bands.A performance metric,the Ratio of relative Bandwidth to Volume(RBV),is introduced to evaluate the antenna's efficiency.Compared to similar designs,the proposed antenna offers a smaller size without sacrificing performance,making it well-suited for BDS airborne applications.
基金Supported by the Zhejiang Provincial Natural Science Foundation of China,No.LTGY24H160006Jiaxing Medical Key Discipline,No.2023-ZC-015.
文摘BACKGROUND Rectal cancer is one of the common digestive system malignant tumors around the world.Its early diagnosis and staging are crucial for rectal cancer treatment and prognosis.In recent years,tumor markers have gradually received attention in early screening,treatment monitoring and prognostic evaluation of cancer,but their predictive role in rectal cancer staging and differentiation is still unclear.AIM To assess the prognostic value of tumor markers alpha-fetoprotein(AFP)cancer antigen 72-4(CA72-4),carbohydrate antigen 19-9(CA19-9),and carcinoembryonic antigen(CEA),alongside multimodal magnetic resonance imaging(MRI),for staging and differentiating rectal cancer in patients.METHODS This study retrospectively analyzed 167 patients with rectal cancer who were treated at our institution from January 2020 to December 2024.Each patient underwent serological testing and multimodal MRI for diagnosis.Histopathological examination after surgical resection or imaging based on follow-up was used as the gold standard.According to the T stage and differentiation degree,patients were divided into low stage group(T1-T2)and high stage group(T3-T4).In addition,they were divided into low-differentiation groups and high-differentiation groups according to their differentiation degree.We compared the accuracy,sensitivity and specificity of tumor marker levels and MRI in rectal cancer stage and differentiation.RESULTS The study's findings indicate that in the context of rectal cancer T staging,there is substantial concordance between MRI and clinicopathological assessments,with a Kappa coefficient of 0.789(P<0.001).Similarly,for various degrees of tumor differentiation,MRI and clinicopathological evaluations demonstrated substantial agreement,with a Kappa coefficient of 0.651(P<0.001).Notably,the concentrations of tumor markers CA19-9,CA72-4,CEA,and AFP were significantly elevated in the T3-T4 stage compared to the T1-T2 stage.Furthermore,these markers were significantly higher in the low-differentiation group compared to the high-differentiation group(P<0.05).The combined use of tumor markers and MRI for preoperative T staging of rectal cancer yielded a diagnostic sensitivity of 93.7%and a specificity of 94.6%,as evidenced by the receiver operating characteristic analysis,with an area under the curve of 0.947.For tumor differentiation,the diagnostic sensitivity and specificity were 93.6%and 97.1%,respectively,with an area under the curve of 0.978(95%confidence interval:0.946-1.000),surpassing the accuracy of individual detection methods.CONCLUSION The CA19-9,CA72-4,CEA and AFP tumor markers combined with multimodal MRI have high sensitivity and specificity in diagnosing rectal cancer stage and differentiation.Their diagnostic efficacy is significantly better than that of single tests,which can effectively improve the predictive ability of rectal cancer stage and differentiation,provide a more reliable diagnostic reference for clinical practice,and have important clinical significance.
基金Project supported by the Open Research Program of the State Key Laboratory of Millimeter Waves,China(Grant No.K201926)the Postgraduate Research&Practice Innovation Program of Jiangsu Province,Chinathe Nanjing University of Posts and Telecommunications Scientific Foundation,China(Grant No.NY215137)
文摘We propose a dual-polarized lens antenna system based on isotropic metasurfaces for 12 GHz applications. The metasurface lens is composed of subwavelength unit cells（0.24λ0） with metallic strips etched on the top and bottom sides of the unit cell, and a cross-slots metallic layer in the middle that serves as the ground. The multimode resonance in the unit cell can realize a large phase shift（covering 0？–360？）, and the total transmission efficiency of the lens is above 80%.The feed antenna at the focal point of the lens is a broadband dual-polarized microstrip antenna. Both the simulated and the measured results demonstrate that the dual-polarized lens antenna system can realize a gain of more than 16.1 dB, and an input port isolation of more than 25.0 dB.
基金Project supported by the National Natural Science Foundation of China(Grant No.61371009)the Fund from the Chinese Ministry of Science and Technology(Grant No.2014AA032703)
文摘This study presents two multimode stepped-impedance structures to design single-and dual-band filters. Transmission zeroes are introduced for the single-band filter by using dual-mode stepped-impedance resonators. The single-band filter with high selectivity is centered at 6.02 GHz and has a fractional bandwidth （FBW） of 25.6%. Four stubs （two low frequency and two high frequency ones） are connected to the rectangular patch in the center to construct a quadruple-mode resonator. The independent conditions of the center frequencies of the high and low bands of the resonator are analyzed. A dual-band filter, which operates at 1.53 GHz and 2.44 GHz with FWBs of 12.1% and 14.1%, respectively is designed. The single-and dual-band filters are both fabricated with double-sided YBCO films and they can be used in mobile and satellite communications.
基金The Yancheng Key Research and Development Program(Social Development),No.YCBE202324。
文摘Accurate preoperative prediction of lymph node metastasis(LNM)in esophageal cancer(EC)patients is of crucial clinical significance for treatment planning and prognosis.AIM To develop a clinical radiomics nomogram that can predict the preoperative lymph node(LN)status in EC patients.METHODS A total of 32 EC patients confirmed by clinical pathology(who underwent surgical treatment)were included.Real-time fluorescent quantitative reverse transcription-polymerase chain reaction was used to detect the expression of B7-H3 mRNA in EC tissue obtained during preoperative gastroscopy,and its correlation with LNM was analyzed.Radiomics features were extracted from multi-modal magnetic resonance imaging of EC using Pyradiomics in Python.Feature extraction,data dimensionality reduction,and feature selection were performed using XGBoost model and leave-one-out cross-validation.Multivariable logistic regression analysis was used to establish the prediction model,which included radiomics features,LN status from computed tomography(CT)reports,and B7-H3 mRNA expression,represented by a radiomics nomogram.Receiver operating characteristic area under the curve(AUC)and decision curve analysis(DCA)were used to evaluate the predictive performance and clinical application value of the model.RESULTS The relative expression of B7-H3 mRNA in EC patients with LNM was higher than in those without metastasis,and the difference was statistically significant(P<0.05).The AUC value in the receiver operating characteristic(ROC)curve was 0.718(95%CI:0.528-0.907),with a sensitivity of 0.733 and specificity of 0.706,indicating good diagnostic performance.The individualized clinical prediction nomogram included radiomics features,LN status from CT reports,and B7-H3 mRNA expression.The ROC curve demonstrated good diagnostic value,with an AUC value of 0.765(95%CI:0.598-0.931),sensitivity of 0.800,and specificity of 0.706.DCA indicated the practical value of the radiomics nomogram in clinical practice.CONCLUSION This study developed a radiomics nomogram that includes radiomics features,LN status from CT reports,and B7-H3 mRNA expression,enabling convenient preoperative individualized prediction of LNM in EC patients.
文摘BACKGROUND A primary central nervous system lymphoma(PCNSL)presenting with massive hemorrhage is a rare occurrence that is difficult to distinguish from a high-grade glioblastoma.Comprehensive descriptions of the imaging characteristics of such tumors have not yet been reported.Herein,we reported a case of a PCNSL with massive hemorrhage by presenting the imaging features of computed tomography(CT)imaging and structural and perfusion magnetic resonance imaging(MRI).CASE SUMMARY A 48-year-old man presented with headache lasting for 10 d.CT of the brain showed a round,heterogeneous,high-density lesion with surrounding edema in the right temporal lobe.For further diagnosis,a series of MRI examinations of the brain were subsequently performed,and a hemorrhagic lesion with ring-like enhancement was determined.The whole lesion was relatively hypoperfused on arterial spin labeling images.Surgical resection of the lesion and histopathological examination confirmed that the lesion was a diffuse large B-cell lymphoma with massive hemorrhage.CONCLUSION PCNSLs with hemorrhage occur very rarely,and structural and perfusion MRI examinations are requested exceedingly rarely.This case provided insight into some characteristics of a hemorrhagic lymphoma on CT and MRI examinations.Perfusion MRI examination may be useful for the differential diagnosis of PCNSLs and other brain tumors.
基金funding from the National Natural Science Foundation of China (Grant No.81771242)the Shanghai Pujiang Program (Grant No.20PJ1402200)。
文摘A dural arteriovenous fistula(DAVF) is an abnormal linkage connecting the arterial and venous systems within the intracranial dura mater. A basicranial emissary vein DAVF drains into the cavernous sinus and the ophthalmic vein, similar to a cavernous sinus DAVF. Precise preoperative identification of the DAVF location is a prerequisite for appropriate treatment. Treatment options include microsurgical disconnection, endovascular transarterial embolization(TAE), transvenous embolization(TVE), or a combination thereof. TVE is an increasingly popular approach for the treatment of DAVFs and the preferred approach for skull base locations, due to the risk of cranial neuropathy caused by dangerous anastomosis from arterial approaches. Multimodal magnetic resonance imaging(MRI) can provide anatomical and hemodynamic information for TVE. The therapeutic target must be precisely embolized in the emissary vein, which requires guidance via multimodal MRI. Here, we report a rare case of successful TVE for a basicranial emissary vein DAVF, utilizing multimodal MRI assistance. The fistula had vanished, pterygoid plexus drainage had improved, and the inferior petrosal sinus had recanalized, as observed on 8-month follow-up angiography. Symptoms and signs of double vision, caused by abduction deficiency, disappeared. Detailed anatomic and hemodynamic assessment by multimodal MRI is the key to guiding successful diagnosis and treatment.
文摘Objective This study aims to explore the application value of multimodal magnetic resonance imaging(MRI)in the diagnosis of atypical hepatocellular carcinoma(HCC).Methods 80 patients with atypical HCC who were admitted to our hospital from August 2018 to February 2020 were selected as the research subjects.All patients underwent dynamic computed tomography(CT)enhancement scans,and then multimodal MRI scans,including an MRI plain scan,dynamic contrastenhancement(DCE),and diffusion-weighted imaging(DWI).Then,the image data were analyzed.Results The diagnostic accuracy of the observation group(95.00%)was significantly higher than that of the control group(75.00%).This difference was statistically significant(χ2=6.128,P<0.05).With the increase of the b value,the apparent diffusion coefficient(ADC)values of the liver tissue and liver cancer tissue gradually decreased.Compared with normal liver tissue,the ADC value of liver cancer tissue was significantly lower than that of normal liver tissue(P<0.05).A plain MRI scan of 89 lesions,DCE examination of 93 lesions,(1)7 lesions were slow-rising and fast-falling;(2)72 lesions were fast-rising and fast-falling;(3)10 were platform-type lesions;(4)4 lesions had no enhancement.Conclusion The diagnostic efficiency of a multimodal MRI in the diagnosis of atypical HCC is high,and it has particular clinical application value.
基金supported in part by the National Key Research and Development Program of China(No.2021YFF1201200)National Natural Science Foundation of China(Nos.62302119,62172444,and 62476291)+3 种基金Science and Technology Innovation Program of Hunan Province(No.2022RC1031)Guizhou Provincial Basic Research Program(Natural Science)(No.QKHZK[2024]603)Guiyang City Science and Technology Plan Project(No.[2024]2-18)High Performance Computing Center of Central South University.
文摘Glioma survival risk prediction is of great significance for the individualized treatment and assessment programs.Currently,most deep learning based survival prediction paradigms rely on invasive and expensive histopathology and genomics methods.However,magnetic resonance imaging(MRI)has emerged as a promising non-invasive alternative with significant prognostic potential.To leverage the benefits of MRI,we propose a segmentation-guided fully automated multimodal MRI-based survival network(SGS-Net),which can simultaneously perform glioma segmentation and survival risk prediction.Specifically,the task interrelation is addressed using a hybrid convolutional neural network-Transformer(CNN-Transformer)encoder to represent the shared high-level semantic features by co-training a decoder for glioma segmentation and a Cox model for survival prediction.Then,to ensure the effective representation of the high-level features,glioma segmentation as an auxiliary task is utilized to guide survival prediction by jointly optimizing the segmentation loss and the Cox partial log-likelihood loss.Furthermore,a pair-wise ranking loss is designed to allow the network to learn the survival difference between patients.To balance the multi-task losses,an uncertain weight manner is adopted to adaptively adjust the weights for preventing task bias.Finally,the proposed SGS-Net is assessed using a publicly available multi-institutional dataset.Experimental and visual results show that SGS-Net achieves promising segmentation performance and obtains a C-index of 81.07%for survival risk prediction,which outperforms several existing state-of-the-art methods and even histopathology-based methods.In addition,Kaplan-Meier survival analysis confirms that the prognosis risk generated by SGS-Net is consistent with the prior prognosis based on the grading or genotyping paradigms.
基金supported by the National Natural Science Foundation of China(Grant Nos.61571468,61801348,61971475,and 62271364)the Key Research and Development Program of Shaanxi(Grant No.2023-GHZD-45).
文摘During the past several decades,the multimode resonator(MMR)technique has been extensively investigated and widely used,with successful exploration of a variety of high-performance patch antennas,slot antennas,dielectric resonant antennas,dipole antennas,and so on.In this review paper,we summarize the research milestones for these MMR antennas worldwide as one of the most contributive research teams in this field.First,the basic working principles of the MMR technique are clearly illustrated and studied,including mode excitation,mode suppression,impedance performance improvement,and radiation performance improvement.Next,the research topics regarding impedance performance enhancement,i.e.,widebandwidth operation,multibandwidth operation,and mutual coupling reduction,based on the MMR method are intensively described.After that,the relevant works on radiation performance enhancement,i.e.,high-gain,wide-beamwidth,multibeam,multipolarization,low-cross-polarization,filtering-response,and leaky-wave antennas,based on the MMR method are extensively illustrated.By using this technique,several ideas about operating frequency reallocation,electric-field null control,radiation pattern reshaping,and efficiency null generation of the antennas are proposed and demonstrated by our team for the first time.In addition,the application of the MMR technique for wireless communication systems is introduced and presented,such as implant communication,wireless power transfer,and multiple-input multiple-output communication.With these arrangements,exploration and reporting of more interesting and useful MMR design methods can be anticipated in the future.
基金partially supported by STI2030-Major Projects(No.2021ZD0200200)the Natural Science Foundation of China(Nos.82072099,91432302,31620103905,and 62250058)+1 种基金the Strategic Priority Research Program of Chinese Academy of Sciences(No.XDB32030200)the National Key Research&Development Program of China(No.2017YFA0105203)
文摘The brain is a complex organ that requires precise mapping to understand its structure and function.Brain atlases provide a powerful tool for studying brain circuits,discovering biological markers for early diagnosis,and developing personalized treatments for neuropsychiatric disorders.Neuromodulation techniques,such as transcranial magnetic stimulation and deep brain stimulation,have revolutionized clinical therapies for neuropsychiatric disorders.However,the lack of fine-scale brain atlases limits the precision and effectiveness of these techniques.Advances in neuroimaging and machine learning techniques have led to the emergence of stereotactic-assisted neurosurgery and navigation systems.Still,the individual variability among patients and the diversity of brain diseases make it necessary to develop personalized solutions.The article provides an overview of recent advances in individualized brain mapping and navigated neuromodulation and discusses the methodological profiles,advantages,disadvantages,and future trends of these techniques.The article concludes by posing open questions about the future development of individualized brain mapping and navigated neuromodulation.
基金supported by the National Natural Science Foundation of China(82072271,82241072,82072294)the National Key Research and Development Program of China(2021YFC2501402,2021YFC0122601)+8 种基金the Beijing Natural Science Foundation(7222095,7222091)the Peak Talent Program of Beijing Hospital Authority(DFL20191701)the Capital’s Funds for Health Improvement and Research(2022-1-1151)the Research and Translational Application of Clinical Characteristic Diagnostic and Treatment Techniques in Capital City(Z221100007422055)the Beijing Research Center for Respiratory Infectious Diseases(BJRID2024-001)the Beijing Hospitals Authority Innovation Studio of Young Staff Funding Support(2021037)the High-level Public Health Technical Personnel Construction Project(2022-1-007)the High-level Public Health Specialized Talents Project of Beijing Municipal Health commission(2022-02-20)the Beijing Key Laboratory for HIV/AIDS Research(BZ0089).
文摘Integrase strand transfer inhibitors(INSTIs)have emerged as the first‐line choice for treating human immunodeficiency virus(HIV)infection due to their superior efficacy and safety.However,the impact of INSTIs on the development of neuropsychiatric conditions in people living with HIV(PLWH)is not fully understood due to limited data.In this study,we conducted a cross‐sectional examination of PLWH receiving antiretroviral therapy,with a specific focus on HIV‐positive men who have sex with men(MSM)on INSTI‐based regimens(n=61)and efavirenz(EFV)‐based regimens(n=28).Participants underwent comprehensive neuropsychiatric evaluations and multimodal magnetic resonance imaging(MRI)scans,including T1‐weighted images and resting‐state functional MRI.Compared to the EFV group,the INSTI group exhibited primarily reduced gray matter volume(GMV)in the right superior parietal gyrus,higher regional homogeneity(ReHo)in the left postcentral gyrus,lower ReHo in the right orbital part of the inferior frontal gyrus,and increased voxel‐wise functional connectivity for the seed region in the left inferior temporal gyrus with clusters in the right cuneus.Furthermore,the analysis revealed a main effect of antiretroviral drugs on GMV changes,but no main effect of neuropsychiatric disorders or their interaction.The repeated analysis of participants who did not switch regimens confirmed the GMV changes in the INSTI group,validating the initial findings.Our study demonstrated gray matter atrophy and functional brain changes in PLWH on INSTI‐based regimens compared to those on EFV‐based regimens.These neuroimaging results provide valuable insights into the characteristics of brain network modifications in PLWH receiving INSTI‐based regimens。
基金supported by the National Key Research and Development Program of China(Grant No.2021YFE0205900)the Key Technologies R&D Program of Jiangsu(Prospective and Key Technologies for Industry)(Grant Nos.BE2022067 and BE2022067-2)。
文摘In this article,studies on the multimode excitation problem of waveguides and antennas,the balance/unbalance mech-anism and the balanced feeding techniques in dipole antenna systems are first briefly historically reviewed.In this context,general-ized odd-even mode theory is advanced to quantitatively and approximately describe the mutual coupling effect between a feed line and an antenna.As is mathematically deduced and demonstrated,the modal parity mismatch between the feed line and the antenna should ultimately dominate the unbalance phenomenon in antenna systems.Thus,an elegant,closed-form formula is derived to ap-proximately calculate the“unbalance degree”of a straight dipole off-center fed by a symmetric twin-wire line.Design approaches for the simplest,linear,1-D multimode resonant antennas are introduced.Moreover,the“falling tone excitation”law gauged based on prototype dipoles is revealed and used to develop a mode synthesis design approach for microstrip patch antennas(MPAs)and 2-D sectorial electric dipole antennas.Design examples with distinctive radiation performance are presented and discussed.Finally,possible development trends of multimode resonant antennas are prospected.
基金We are grateful for support from the National Academy of Engineering(NAE)Grainger Foundation Frontier of Engineering(FOE)Award(FOE2013-005)the National Science Foundation CAREER Award(Grant ECCS-1454570)partial support from the Department of Energy(DOE)EERE Award(Grant DE-EE0006719),a ThinkEnergy Fellowship(X.-Q.Zheng),and the Case School of Engineering.A portion of the device fabrication was performed at the Cornell NanoScale Science and Technology Facility(CNF),a member of the National Nanotechnology Infrastructure Network(NNIN)supported by the National Science Foundation(Grant ECCS-0335765).
文摘Atomic layers of hexagonal boron nitride(h-BN)crystal are excellent candidates for structural materials as enabling ultrathin,two-dimensional(2D)nanoelectromechanical systems(NEMS)due to the outstanding mechanical properties and very wide bandgap(5.9 eV)of h-BN.In this work,we report the experimental demonstration of h-BN 2D nanomechanical resonators vibrating at high and very high frequencies(from~5 to~70 MHz),and investigations of the elastic properties of h-BN by measuring the multimode resonant behavior of these devices.First,we demonstrate a dry-transferred doubly clamped h-BN membrane with~6.7 nm thickness,the thinnest h-BN resonator known to date.In addition,we fabricate circular drumhead h-BN resonators with thicknesses ranging from~9 to 292 nm,from which we measure up to eight resonance modes in the range of~18 to 35 MHz.Combining measurements and modeling of the rich multimode resonances,we resolve h-BN’s elastic behavior,including the transition from membrane to disk regime,with built-in tension ranging from 0.02 to 2 N m−1.The Young’s modulus of h-BN is determined to be EY≈392 GPa from the measured resonances.The ultrasensitive measurements further reveal subtle structural characteristics and mechanical properties of the suspended h-BN diaphragms,including anisotropic built-in tension and bulging,thus suggesting guidelines on how these effects can be exploited for engineering multimode resonant functions in 2D NEMS transducers.
