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Optical erbium oxide (Er 2 O 3) films were prepared by radio frequency (RF) magnetron sputtering to improve the infrared (IR) transmittance of chemical vapor deposition (CVD) diamond. This study aims to analyze the microstructure, composition and optical properties of Er 2 O 3 anti-reflection films at various oxygen/argon ratios. Atomic force microscopy (AFM) analysis was used to detect the surface morphology of chemical oxidation CVD diamond and Er 2 O 3 films. The surface roughness of Er 2 O 3 films decreased with an increase in the oxygen/argon ratio. The crystalline structure of Er 2 O 3 films was analyzed by using X-ray diffraction. Meanwhile, a gradual decrease was observed when the crystallite size and its strain were calculated. This was due to the transformation of partial phases from monoclinic to cubic structures. The chemical composition of Er 2 O 3 films was analyzed by X-ray photoelectron spectroscopy (XPS). The surface of Er 2 O 3 films underwent a transformation from the unstable structure of nonstoichiometric Er 2 O 3-x to the stable structure of Er 2 O 3 with an increase in the level of oxygen. Defect behavior was determined by transmission electron microscopy (TEM). Specifically, dislocation and twinning were observed at a high oxygen/argon ratio, which was mainly attributed to the competitive growth of polycrystalline Er 2 O 3 films. The optical constants of Ψ and △ were shifted to lower wavelengths with increase oxygen/argon ratio. The maximum transmittance of the Er 2 O 3 /diamond film was 79% in the long-wavelength infrared (LWTR) range of 8–12 μm at an oxygen/argon ratio of 1:35. This value was significantly higher than that of the high oxygen/argon ratio. The present study concludes that a low oxygen/argon ratio promotes the growth and IR transmittance of Er 2 O 3 films. [ABSTRACT FROM AUTHOR]

Accurate land cover classification (LCC) is essential for studying global change. Synthetic aperture radar (SAR) has been used for LCC due to its advantage of weather independence. In particular, the dual-polarization (dual-pol) SAR data have a wider coverage and are easier to obtain, which provides an unprecedented opportunity for LCC. However, the dual-pol SAR data have a weak discrimination ability due to limited polarization information. Moreover, the complex imaging mechanism leads to the speckle noise of SAR images, which also decreases the accuracy of SAR LCC. To address the above issues, an improved dual-pol radar vegetation index based on multiple components (DpRVIm) and a new LCC method are proposed for dual-pol SAR data. Firstly, in the DpRVIm, the scattering information of polarization and terrain factors were considered to improve the separability of ground objects for dual-pol data. Then, the Jeffries-Matusita (J-M) distance and one-dimensional convolutional neural network (1DCNN) algorithm were used to analyze the effect of difference dual-pol radar vegetation indexes on LCC. Finally, in order to reduce the influence of the speckle noise, a two-stage LCC method, the 1DCNN-MRF, based on the 1DCNN and Markov random field (MRF) was designed considering the spatial information of ground objects. In this study, the HH-HV model data of the Gaofen-3 satellite in the Dongting Lake area were used, and the results showed that: (1) Through the combination of the backscatter coefficient and dual-pol radar vegetation indexes based on the polarization decomposition technique, the accuracy of LCC can be improved compared with the single backscatter coefficient. (2) The DpRVIm was more conducive to improving the accuracy of LCC than the classic dual-pol radar vegetation index (DpRVI) and radar vegetation index (RVI), especially for farmland and forest. (3) Compared with the classic machine learning methods K-nearest neighbor (KNN), random forest (RF), and the 1DCNN, the designed 1DCNN-MRF achieved the highest accuracy, with an overall accuracy (OA) score of 81.76% and a Kappa coefficient (Kappa) score of 0.74. This study indicated the application potential of the polarization decomposition technique and DEM in enhancing the separability of different land cover types in SAR LCC. Furthermore, it demonstrated that the combination of deep learning networks and MRF is suitable to suppress the influence of speckle noise. [ABSTRACT FROM AUTHOR]

Background: Recently, several studies have focused on the relationship between blood-brain barrier (BBB) impairment and the etiology of Moyamoya disease (MMD). However, in vivo studies investigating about BBB impairment and cortical perfusion in MMD patients were really rare. Methods: This study included 16 patients diagnosed with MMD and 9 patients with atherosclerotic cerebrovascular disease (ACVD); all of who were treated with superficial temporal artery–middle cerebral artery (STA-MCA) bypass. Cortical perfusion was assessed using intraoperative indocyanine green (ICG) videoangiography by calculating the blood flow index (BFI). In addition, we used sodium fluorescein (NaFl) to evaluate the permeability of BBB in vivo during operation. Results: The results showed that BBB impairment in MMD patients was more significant than that in ACVD patients, whereas, the cortical perfusion was comparable between two groups. BFI was significantly improved after STA-MCA bypass both in the MMD group (post-operation vs pre-operation: 109.2 ± 67.7 vs 64.3 ± 35.0, p = 0.004) and the ACVD group (post-operation vs pre-operation: 137.6 ± 89.6 vs 90.8 ± 58.3, p = 0.015). Moreover, BFI was significantly decreased in the cortex with BBB impairment as compared with that in the cortex with intact BBB (impaired BBB vs intact BBB: 55.7 ± 26.5 vs 87.6 ± 55.1, p = 0.025). Following bypass, the cortical perfusion significantly improved in the area of BBB impairment (post-operation vs pre-operation: 93.8 ± 75.2 vs 55.7 ± 26.5, p = 0.004), which was not observed in the BBB intact area (post-operation vs pre-operation: 92.4 ± 50.4 vs 87.6 ± 55.1, p = 0.58). Conclusion: In summary, we observed that BBB impairment in MMD patients was more significant than that in ACVD patients. This study also demonstrated for the first time that cortical perfusion was significantly decreased in the cortex with BBB impairment as compared with that in the cortex with intact BBB in MMD patients. We also observed that After STA-MCA bypass, the cortical perfusion was significantly improved in the cortex with BBB impairment. These results may provide a new insight for BBB impairment and cortical perfusion in the etiology of MMD. [ABSTRACT FROM AUTHOR]

Background Internal carotid artery (ICA) occlusion associated with posterior cerebral artery (PCA) aneurysms is regarded as a rare cerebrovascular disease. Common treatment of aneurysms—direct clipping or coiling—is not taken into consideration for this kind of cerebrovascular property. Combined surgical cerebrovascular reconstruction of the superficial temporal artery−to−middle cerebral artery (STA-MCA) bypass offers a chance to downregulate the hemodynamic stress of aneurysm rupture. Case Description A 46-year-old female presented with a fever and headache 1 month ago. An axial computed tomography scan showed a subarachnoid hemorrhage (SAH). Digital subtraction angiography (DSA) was conducted, and the patient received an STA-MCA bypass following medical treatment for 1 month in the local hospital. Computed tomography angiography and DSA demonstrated an aneurysm located on the right PCA and an occlusion of the right ICA in our hospital. Three days after admission, the right STA-MCA bypass was performed. The patient suffered no neurologic deterioration and lived a normal life. 6 months after the STA-MCA bypass, DSA of the right vertebral artery revealed disappearance of the aneurysm located on the right PCA (P2 segment). Conclusions Owing to ICA occlusion, the gap of hemodynamic stress between the posterior segment of the circle of Willis and anterior segment of the circle of Willis enlarged. This may lead to a ruptured PCA aneurysm. In this case, the aneurysm disappeared following an STA-MCA bypass. STA-MCA bypass may be one of the major reasons downregulating the gap, which can be regarded as an effective option concerning such aneurysms. [ABSTRACT FROM AUTHOR]

[Display omitted] • The La-doped Er 2 O 3 anti-reflection films was prepared by the power of magnetron sputtering. • The compound of La 2 O 3 formed along the grain boundary of the columnar crystal structure of the polycrystalline film. • The highest hardness and yield strength of the La-doped Er 2 O 3 film was two times higher than that of pure Er 2 O 3 film. • The transmittance of the La-doped Er 2 O 3 anti-reflection films only decreased 1% after erosion. The composition and microstructure consisting of anti-reflection films was obtained by the power of magnetron sputtering. X-ray photoelectron spectroscopy (XPS) and High-resolution transmission electron microscopy (HRTEM) provided evidence to support that the doping La element exists as oxide in the grain boundaries of the matrix Er 2 O 3 films. The undoped and La-doped Er 2 O 3 films show a columnar crystal structure of the main cubic (2 2 2) plane. Twinning and a large number of dislocations show up in the undoped Er 2 O 3 films due to the competitive growth of the columnar crystal. In addition, the La-doped Er 2 O 3 films show a lower roughness (RMS) value in comparison with undoped Er 2 O 3 films. The grain size of columnar crystals decreases significantly with increasing La concentration in the La-doped Er 2 O 3 films. The fine grains resulted in the La-doped Er 2 O 3 films developing high mechanical and impact resistance properties, with an increase in hardness from 12.6 ± 2.1 GPa to 26.1 ± 3.4 GPa and the eroding area rate decreasing from 38.9 % to 1.9 %. Moreover, the La-doped Er 2 O 3 anti-reflection films on the chemical vapor deposition (CVD) diamond substrate maintained 74 % transmittance in the long-wavelength infrared range of 8–12 μm after sand eroding. [ABSTRACT FROM AUTHOR]

Diamond has attracted increasing attention because it has high thermal conductive. Here, a freestanding diamond thermal conductive film with a diameter of about 7 in. and an average thickness of 1.54 mm was prepared by DC arc plasma jet CVD with multi-stage magnetic fields. Specifically, the thickness uniformity was ensured by adding the magnetic field during the deposition of the freestanding diamond film. The morphology, structure and thermal conductivity of the diamond film were studied. The results showed that the expansion area of the DC arc plasma approached the surface of the substrate increasing duo to add the bottom magnetic field. Structural characterization revealed that the grain of the diamond film in the arc main were coarse, affected by the shape of DC arc plasma, while in the arc center and edge were fine. The main orientation of polycrystalline structure of the diamond film was the crystalline plane of (220). The Raman peaks of diamond film in different areas moved to a higher wavelength, indicating the existence of compressive stress inside the diamond film. The coarse columnar grain and a few grain boundaries were in the arc main. Therefore, the average value of the thermal conductivity (k ⊥) of diamond film measured in the arc main was 1728.9 ± 4.9 W/(m·k). Meanwhile, the thermal conductivity of the arc center and edge area was lower than that of the arc main. [Display omitted] • A freestanding diamond thermal conductive film with a diameter of about 7 in. was prepared. • DC arc plasma jet CVD with multi-stage magnetic fields was adopted. • The average value of the thermal conductivity (k ⊥) of diamond film measured in the arc main was 1728.9 ± 4.9 W/(m·k). [ABSTRACT FROM AUTHOR]

Synthetic aperture radar (SAR) image is an effective remote sensing data source for geographic surveys. However, accurate land cover mapping based on SAR image in areas of complex terrain has become a challenge due to serious geometric distortions and the inadequate separation ability of dual-polarization data. To address these issues, a new land cover mapping framework which is suitable for complex terrain is proposed based on Gaofen-3 data of ascending and descending orbits. Firstly, the geometric distortion area is determined according to the local incident angle, based on analysis of the SAR imaging mechanism, and the correct polarization information of the opposite track is used to compensate for the geometric distortion area, including layovers and shadows. Then, the dual orbital polarization characteristics (DOPC) and dual polarization radar vegetation index (DpRVI) of dual-pol SAR data are extracted, and the optimal feature combination is found by means of Jeffries–Matusita (J-M) distance analysis. Finally, the deep learning method 2D convolutional neural network (2D-CNN) is applied to classify the compensated images. The proposed method was applied to a mountainous region of the Danjiangkou ecological protection area in China. The accuracy and reliability of the method were experimentally compared using the uncompensated images and the images without DpRVI. Quantitative evaluation revealed that the proposed method achieved better performance in complex terrain areas, with an overall accuracy (OA) score of 0.93, and a Kappa coefficient score of 0.92. Compared with the uncompensated image, OA increased by 5% and Kappa increased by 6%. Compared with the images without DpRVI, OA increased by 4% and Kappa increased by 5%. In summary, the results demonstrate the importance of ascending and descending orbit data to compensate geometric distortion and reveal the effectiveness of optimal feature combination including DpRVI. Its simple and effective polarization information compensation capability can broaden the promising application prospects of SAR images. [ABSTRACT FROM AUTHOR]

To improve the transmittance of chemical vapor deposition (CVD) diamond, erbium(III) oxide (Er 2 O 3) antireflective films were deposited on CVD diamond substrates by radio frequency (RF) magnetron sputtering. Effects of deposition temperature on structure, chemical composition and properties of the samples were investigated. A strong correlation was observed between the deposition temperature and crystalline structure evolution of the Er 2 O 3 antireflective films. With rising deposition temperature, the deposition rate, grain size and surface roughness of the Er 2 O 3 antireflective films increased. Changes of composition and chemical bonding of the films were analyzed. Results showed that the amount of bonding between Er and O atoms surface as the temperature increased. The films were structured by amorphous, monoclinic and cubic phase, with preferential orientations of C-Er 2 O 3 {222} at deposition temperature increased to 400 °C. A thickness of 10 nm transition layer was observed between the Er 2 O 3 antireflective films and the CVD diamond substrates by transmission electron microscopy (TEM). Moreover, the transition layer feature primarily consisted of Er, O and C. The hardness and modulus of Er 2 O 3 antireflective films were increased for higher deposition temperature, which positively affects the IR transmittance and adhesion strength of the Er 2 O 3 antireflective films on CVD diamond substrates. • The maximum transmittance of Er 2 O 3 /diamond sample was 80% in 7–11 μm range. • Texturization of Er 2 O 3 film interface was studied by HRTEM. • The higher deposition temperature favors crystallization of Er 2 O 3 film. • This study meets the requirements of windows for infrared (IR) imaging systems coating in the LWIR range. [ABSTRACT FROM AUTHOR]

Complex middle cerebral artery (MCA) aneurysms, including aneurysms that are sizeable (large or giant), fusiform, wide-necked or calcified, remain a significant challenge during microsurgical clipping or endovascular coiling as treatment strategies. In the present study, a retrospective analysis of cases of this type of aneurysm treated between August 2012 and December 2019 was performed. From the hospital's database, a total of 13 patients (7 males and 6 females) with a mean age of 39.0 years (range, 13-65 years) were identified. The mean size of the aneurysms was 17.5 mm (range, 3.9-35.0 mm). A total of four patients (30.8%) had ruptured aneurysms and nine (69.2%) had unruptured aneurysms. All aneurysms were treated by proximal occlusion of the parent artery, trapping or excision combined with cerebral revascularization. The bypasses performed included 10 extracranial-intracranial bypasses and 3 intracranial-intracranial bypasses (1 end-to-end re-anastomosis, 1 interpositional graft and 1 end-to-side reimplantation). Postoperative angiography confirmed that the bypass patency was 92.3% and the clinical outcomes were indicated to be favorable, with a modified Rankin Scale score ≤2 in 12 out of 13 patients (92.3%) at the last follow-up. Taken together, the results of the present analysis suggested that treatment strategies for complex MCA aneurysms should depend on the status and characteristics of the aneurysm, including aneurysm size, location and morphology. For aneurysms that lack perforating arteries in the aneurysm dome, clip trapping or aneurysm excision with or without bypass are preferred as treatment strategies. When there are perforating arteries (particularly the lenticulostriate artery) arising from the aneurysm dome, however, the aneurysms should be treated with bypass followed by proximal occlusion of the parent artery or clip reconstruction. [ABSTRACT FROM AUTHOR]

Synthetic Aperture Radar (SAR) images have been widely used for surface water identification due to their all-weather capabilities. However, the presence of inherent speckle noise in SAR data poses a challenge for accurate water identification. Additionally, annotating high-quality water body samples requires significant human labour, which can be costly and time-consuming. Aiming at the above problems, a noise-robust automatic water identification architecture without artificial labels is proposed. First, a two-stage automatic sample collection method that utilizes k-means++ clustering and morphological concepts is designed. Then, a weakly supervised noise-resistant SAR water body segmentation method NRM-ACUNet has been developed based on U-Net combined with LNR-Dice loss function and Conditionally Parameterized Convolutions (CondConv) to minimize the impact of sample noises. Experimental results show that the morphological processing can improve water body sample quality compared to k-means++, and compared with U-Net, NRM-ACUNet performs superior with noise-containing pseudo-samples, achieving 96.8% F1 accuracy and 52.06% accuracy improvement. [ABSTRACT FROM AUTHOR]

• 21% increase of maximum transmittance of Er2O3 films deposited on diamond coatings. • Negative electrical bias induces the formation of monoclinic Er2O3 on Si(110). • Monoclinic Er2O3 effectively improve the transmittance of the diamond coating. Er 2 O 3 anti-reflection films were deposited on the surface of the chemical vapor deposited diamond films and Si(100) substrates by radio frequency magnetron sputtering. The microstructure of the Er 2 O 3 thin films and the interfacial layer were investigated by means of scanning electron microscopy, X-ray diffraction, atomic force microscopy and transmission electron microscopy. The refractive index, hardness and transmittance of the films were measured by ellipsometry, nanoindentation measurements, and Fourier transformed infrared spectroscopy. Results revealed that the bias induces the formation of a monoclinic phase and the nucleation of the Er 2 O 3 thin films is mainly observed along the (222) plane. A high-resolution TEM image revealed a 2.5-nm-thick amorphous layer at the interface between the Si substrate and Er 2 O 3 film. Notably, monoclinic Er 2 O 3 films can considerably improve the transmittance of the diamond film in the long-wavelength infrared range of 8–12 μm via the reduction of the refractive index. However, the introduction of the monoclinic phase led to the decrease of the hardness and elastic modulus of the films; hence, controlling a suitable amount of the monoclinic phase may play an extremely important role in the mechanical and optical properties of the Er 2 O 3 films. [ABSTRACT FROM AUTHOR]

Synthetic Aperture Radar (SAR), as a microwave sensor that can sense a target all day or night under all-weather conditions, is of great significance for detecting water resources, such as coastlines, lakes and rivers. This paper reviews literature published in the past 30 years in the field of water body extraction in SAR images, and makes some proposals that the community working with SAR image waterbody extraction should consider. Firstly, this review focuses on the main ideas and characteristics of traditional water body extraction on SAR images, mainly focusing on traditional Machine Learning (ML) methods. Secondly, how Deep Learning (DL) methods are applied and optimized in the task of water-body segmentation for SAR images is summarized from the two levels of pixel and image. We also pay more attention to the most popular networks, such as U-Net and its modified models, and novel networks, such as the Cascaded Fully-Convolutional Network (CFCN) and River-Net. In the end, an in-depth discussion is presented, along with conclusions and future trends, on the limitations and challenges of DL for water-body segmentation. [ABSTRACT FROM AUTHOR]

Crop type identification is the initial stage and an important part of the agricultural monitoring system. It is well known that synthetic aperture radar (SAR) Sentinel-1A imagery provides a reliable data source for crop type identification. However, a single-temporal SAR image does not contain enough features, and the unique physical characteristics of radar images are relatively lacking, which limits its potential in crop mapping. In addition, current methods may not be applicable for time-series SAR data. To address the above issues, a new crop type identification method was proposed. Specifically, a farmland mask was firstly generated by the object Markov random field (OMRF) model to remove the interference of non-farmland factors. Then, the features of the standard backscatter coefficient, Sigma-naught (σ0), and the normalized backscatter coefficient by the incident angle, Gamma-naught (γ0), were extracted for each type of crop, and the optimal feature combination was found from time-series SAR images by means of Jeffries-Matusita (J-M) distance analysis. Finally, to make efficient utilization of optimal multi-temporal feature combination, a new network, the convolutional-autoencoder neural network (C-AENN), was developed for the crop type identification task. In order to prove the effectiveness of the method, several classical machine learning methods such as support vector machine (SVM), random forest (RF), etc., and deep learning methods such as one dimensional convolutional neural network (1D-CNN) and stacked auto-encoder (SAE), etc., were used for comparison. In terms of quantitative assessment, the proposed method achieved the highest accuracy, with a macro-F1 score of 0.9825, an overall accuracy (OA) score of 0.9794, and a Kappa coefficient (Kappa) score of 0.9705. In terms of qualitative assessment, four typical regions were chosen for intuitive comparison with the sample maps, and the identification result covering the study area was compared with a contemporaneous optical image, which indicated the high accuracy of the proposed method. In short, this study enables the effective identification of crop types, which demonstrates the importance of multi-temporal radar images in feature combination and the necessity of deep learning networks to extract complex features. [ABSTRACT FROM AUTHOR]

Nd 2 O 3 film is a functional film with great potential application value. In this paper, thinNd 2 O 3 film was prepared on the surface of Si substrates using RF magnetron reactive sputtering. Nd 2 O 3 film with different crystal structures were controlled by changing the deposition temperature. The results show that the Nd 2 O 3 film with a cubic structure can be obtained at 150 °C, while a hexagonal structure appears at 250 °C and above. The refractive indices of the cubic and hexagonal Nd 2 O 3 films were 1.736 and 2.130, respectively. Moreover, the principle of the influence of deposition temperature on the refractive index of the film was illustrated. The hardness and the elastic modulus of the cubic Nd 2 O 3 film were 6.3 GPa and 102 GPa, respectively, which are much lower than the 9.9 GPa and 145 GPa of the hexagonal Nd 2 O 3 film. In addition, with a double-sided cubic Nd 2 O 3 film, the maximum transmittance of the diamond film reached 87.54%. The results show that the Nd 2 O 3 film is an anti-reflection film suitable for optical applications. • Nd 2 O 3 films with cubic and hexagonal structures were prepared, respectively. • The mechanical and optical properties of two kinds of Nd 2 O 3 films were compared. • Hexagonal Nd 2 O 3 film shows hardness of 9.9 GPa and elastic modulus of 145 GPa. • Diamond presents the maximum transmittance of 87.54% at 11.2 μm with Nd 2 O 3 films. [ABSTRACT FROM AUTHOR]

The fabrication of GaN-on-diamond structure by the process of diamond growth on GaN technology is becoming more and more attractive for high-power GaN devices. However, due to the high-temperature steps employed during the GaN epitaxial layer transfer process, significant stress accumulates in the GaN-on-diamond structure and induces the formation of cracks or deformations in the GaN layer. To improve the stress characteristics of the GaN layer, in this work, dual-sided diamond film deposition was carried out to accomplish the GaN-on-diamond structure. The surface morphology, interface microstructure and crystal quality of diamond on GaN were analyzed by using scanning electron microscopy, atomic force microscopy, transmission electron microscopy and X-ray diffraction. The results showed that the stress accumulation originating from the GaN epitaxial layer transfer process was effectively alleviated as compared with other reporteds in the literature and that the crystal quality of the GaN was only slightly altered. The stress relaxation was attributed to the low-quality diamond used as the temporary carrier during the GaN transfer process. In addition, a thin SiC transition layer in the interface is also beneficial in alleviating the mismatch between the coefficients of thermal expansion for the GaN and the diamond. [ABSTRACT FROM AUTHOR]

Background: Superficial temporal artery-middle cerebral artery (STA-MCA) bypass combined with an encephaloduromyosynangiosis (EDMS) had gained significant role in treating chronic cerebral ischemia. Invasiveness and costs of intraoperative digital subtraction angiography (DSA) limited its application in operations. Objective: To find the reliable parameters for determining bypass patency with intraoperative micro-Doppler (IMD) sonography and compare the diagnostic accuracy of indocyanine green (ICG) videoangiography with IMD in combined bypass. Method: One hundred fifty bypass procedures were included and divided into patent and non-patent groups according to postoperative computed tomography angiography (CTA) within 72 h. The surgical process was divided into four phases in the following order: preparation phase (phase 1), anastomosis phase (phase 2), the temporalis muscle closure phase (phase 3), and the bone flap closure phase (phase 4). The IMD parameters were compared between patent and non-patent groups, and then compared with the patency on CTA by statistical analyses. IMD with CTA, ICG videoangiography with CTA, IMD with ICG videoangiography were performed to assess bypass patency. The agreement between methods was evaluated using kappa statistics. Results: No significant differences of baseline characteristics were found between patent and non-patent group. Parameters in the STA were different between patent and non-patent groups in phases 2, 3, and 4. In patent group, Vm was apparently higher and PI was lower in phases 2, 3, and 4 compared with phase 1 (P <.001). In non-patent group, no differences of Vm and PI were found within inter-group. The best cutoff value of IMD in the STA to distinguish patent from non-patent bypasses was Vm in phase 4 > 17.5 cm/s (sensitivity 94.2%, specificity 100%). In addition, the agreement for accessing bypass patency was moderate between ICG videoangiography and CTA (kappa = 0.67), IMD and ICG videoangiography (kappa = 0.73), and good between IMD and CTA (kappa = 0.86). Conclusion: ICG videoangiography could directly display morphology changes of bypass. IMD could be used for providing half-quantitative parameters to assess bypass patency. Vm in phase 4 > 17.5 cm/s suggesting the patency of bypass on CTA would be good. Also, compared with ICG videoangiography, IMD had more accuracy. [ABSTRACT FROM AUTHOR]

Cerebral revascularization is an effective measure for dealing with complicated intracranial aneurysms and ischemic cerebrovascular disease. Intraoperative thrombosis causing bypass occlusion is a severe issue that causes devastating consequences for complications in revascularization. We report our experiences regarding salvage maneuvers for intraoperative thrombosis in cerebral revascularization procedures and discuss the characteristics and culprits. We investigated 720 consecutive patients who underwent cerebral revascularization at First Affiliated Hospital of Soochow University from January 2013 to October 2021, including 688 patients who underwent superficial temporal artery (STA)−middle cerebral artery (MCA) bypass and 32 patients who underwent extracranial artery−radial artery (ECA-RA)−MCA bypass. Forty-one patients experienced intracranial aneurysms, and the remaining 679 patients were involved in moyamoya disease, skull base tumors, intracranial occlusive vascular diseases, or other cerebrovascular diseases. All clinical characteristics, clinical imaging examinations, and neurologic outcomes were studied preoperatively and postoperatively. The patency of bypasses was confirmed by intraoperative Doppler ultrasonography and indocyanine green videoangiography. Seven intraoperative thromboses, which were confirmed by intraoperative Doppler ultrasonography and indocyanine green videoangiography including STA-MCA bypass (n = 5) and ECA-RA-MCA bypass (n = 2) were observed in 720 patients who underwent cerebral revascularization. The anastomotic stoma remained patent in 6 of 7 patients with intraoperative thrombosis after treatment. One case in STA-MCA bypass failed to be salvaged. Of the 4 intraoperative thrombosis in STA-MCA bypass for moyamoya disease cases being successfully saved, 2 were done so by applying absorbable gelatin powder from absorbable gelatin sponge (Gelfoam, Pfizer, New York, New York, USA) around the site of the anastomosis to relieve the downward compression effect of the donor vessel (STA) on the recipient vessel (M4 segment of MCA). One case in ECA-RA-MCA bypass was salvaged by thrombectomy through donor arteriotomy (radial artery) and reanastomosis. The other case was salvaged by complete reanastomosis. All 7 patients who experienced intraoperative thrombosis achieved favorable outcomes at discharge and the 6-month follow-up. Various factors are responsible for intraoperative thrombosis in cerebral revascularization. Relieving the downward compression effect of the donor vessel STA on the recipient vessel M4 segment of MCA by applying Gelfoam around the site of the anastomosis stoma can be recommended to salvage the intraoperative thrombosis in cerebral revascularization. [ABSTRACT FROM AUTHOR]

Background: Superficial temporal artery-middle cerebral artery (STA-MCA) bypass combined with an encephaloduromyosynangiosis (EDMS) had gained significant role in treating chronic cerebral ischemia. Invasiveness and costs of intraoperative digital subtraction angiography (DSA) limited its application in operations. Objective: To find the reliable parameters for determining bypass patency with intraoperative micro-Doppler (IMD) sonography and compare the diagnostic accuracy of indocyanine green (ICG) videoangiography with IMD in combined bypass. Method: One hundred fifty bypass procedures were included and divided into patent and non-patent groups according to postoperative computed tomography angiography (CTA) within 72 h. The surgical process was divided into four phases in the following order: preparation phase (phase 1), anastomosis phase (phase 2), the temporalis muscle closure phase (phase 3), and the bone flap closure phase (phase 4). The IMD parameters were compared between patent and non-patent groups, and then compared with the patency on CTA by statistical analyses. IMD with CTA, ICG videoangiography with CTA, IMD with ICG videoangiography were performed to assess bypass patency. The agreement between methods was evaluated using kappa statistics. Results: No significant differences of baseline characteristics were found between patent and non-patent group. Parameters in the STA were different between patent and non-patent groups in phases 2, 3, and 4. In patent group, Vm was apparently higher and PI was lower in phases 2, 3, and 4 compared with phase 1 (P <.001). In non-patent group, no differences of Vm and PI were found within inter-group. The best cutoff value of IMD in the STA to distinguish patent from non-patent bypasses was Vm in phase 4 > 17.5 cm/s (sensitivity 94.2%, specificity 100%). In addition, the agreement for accessing bypass patency was moderate between ICG videoangiography and CTA (kappa = 0.67), IMD and ICG videoangiography (kappa = 0.73), and good between IMD and CTA (kappa = 0.86). Conclusion: ICG videoangiography could directly display morphology changes of bypass. IMD could be used for providing half-quantitative parameters to assess bypass patency. Vm in phase 4 > 17.5 cm/s suggesting the patency of bypass on CTA would be good. Also, compared with ICG videoangiography, IMD had more accuracy. [ABSTRACT FROM AUTHOR]

Extracranial internal carotid artery (EICA) aneurysm is regarded as a rare lesion. What is more, patients can suffer from EICA aneurysms and hemorrhagic moyamoya disease (MMD) simultaneously. A 38-year-old man was admitted to our hospital and underwent emergent tracheal intubation for hoarseness and breathing difficulty for 1 day. He had a pulsating mass of 2.5 cm in diameter in the left cervical area. Imaging examinations revealed the left EICA aneurysm and MMD. The patient underwent left superficial temporal artery-to-middle cerebral artery (STA-MCA) bypass and ligation of the left EICA simultaneously. Computed tomography revealed hemorrhagic stroke in the right basal ganglia region 20 days after the bypass. The hematoma disappeared 20 days after the stroke. Right bypass was performed 6 months after the left bypass. The patient was discharged with no neurologic abnormalities 10 days after the right bypass. He lived a normal life, and no neurologic abnormalities were found at the 6-month follow-up. Imaging examinations indicated the efficacy of the bilateral STA-MCA bypass and verified the disappearance of the left EICA aneurysm after the ligation. We present a case of EICA aneurysm and hemorrhagic MMD. Ligation of the left ECA eliminates the EICA aneurysm with no neurologic abnormalities. STA-MCA bypass can be regarded as an effective choice for hemorrhagic MMD. Further studies should be performed to confirm the effectiveness of combined surgical revascularization. [ABSTRACT FROM AUTHOR]

Objective: Common carotid artery occlusion (CCAO) is a rare cause of cerebrovascular events. Symptomatic lesions are resistant to medical treatment and revascularization is often required, but there is no consensus on the treatment of CCAO at present. Riles type 1A CCAO is most likely to benefit from revascularization because it has patent outflow tract (internal carotid artery) which was supplied by patent external carotid artery (ECA) from collateral circulation. We described a novel surgical technique improved on the basis of the carotid endarterectomy (CEA) for treatment of Riles type 1A CCAO. Methods: We rigorously screened ten patients with symptomatic Riles type1A CCAO for surgery from January 2017 to May 2019 and performed a full preoperative assessment of the inadequate collateral circulation compensation. Moreover, we retrospectively reviewed our experience of the segmented CEA in the treatment of them in our single center. Results: Segmented CEA was performed on the left side in four cases and on the right side in six cases. The technical success rate of the procedure was 100%. Primary suture was used in nine cases. Only one patient (right CCAO) who had a history of neck radiotherapy was treated by the patch CEA. The mean temporary blocking time during surgery was 52.8 ± 9.15 min. The mean temporary blocking time for treating the upper segment of the common carotid artery (CCA) was 11.1 ± 2.64 min. In the postoperative period, cerebral perfusion on the ipsilateral site improved in all patients, myocardial infarction occurred in one patient, and recurrent laryngeal nerve damage occurred in another. No ischemic events or re-occlusion or restenosis (> 50%) of the treated CCA occurred during the mean follow-up of 32.6 ± 9.3 months. The preoperative mean modified Rankin Scale (mRS) score was 1.9 (range, 1–3; median, 2). At last follow-up for all patients, the mRS score was 1 (range, 0–3; median, 1). Conclusion: Segmented CEA, which utilizes the compensatory effect of collateral circulation, is an effective and safe technique to treat patients suffering from Riles type 1A CCAO with hemodynamic cerebrovascular compromise. [ABSTRACT FROM AUTHOR]

Synthetic aperture radar (SAR), as a wideband radar system, is easily contaminated by radio frequency interference (RFI), which affects the imaging quality of SAR. The subband spectral cancellation (SSC) method and its modifications utilize the SAR single-look complex (SLC) image to realize RFI extraction and mitigation by subtracting between sub-images, which are robust and efficient for engineering applications. In the past, the traditional SSC was often applied to narrowband interference (NBI) mitigation. However, when it was used for wideband interference (WBI) mitigation, it would cause the mitigated image to lose much of its useful information. In contrast, this paper proposes an improved SSC method based on successive cancellation and data accumulation (SSC-SCDA) for WBI mitigation. First, the fast Fourier transform (FFT) is used to characterize the SAR SLC data in the frequency domain, and the average range spectrum algorithm is used to detect whether there are interference components in the SAR SLC data. Then, according to the carrier frequency and bandwidth of the RFI in the frequency domain, the subbands are divided, and a cancellation strategy is formulated. Finally, based on the successive cancellation and data accumulation technology, WBIs can be removed by using only a small percentage of the clean subbands. Based on the simulated experiments, the interference mitigation performance of the proposed method is analyzed when the interference-to-signal bandwidth ratio (ISBR) varies from 20% to 80% under different signal-to-interference-to-noise ratios (SINR). The experimental results based on WBI-contaminated European Space Agency (ESA) Sentinel-1A SAR SLC data demonstrate the effectiveness of the proposed method in WBI mitigation. [ABSTRACT FROM AUTHOR]

The association between high-risk cardiovascular factors and atherosclerotic is well established. However, whether plaque vulnerability is related to specific cardiovascular risk factors remains unknown. The association between plaque vulnerability and cardiovascular risk factors was evaluated in plaques removed in a carotid endarterectomy. Consecutive subjects scheduled for a carotid endarterectomy were recruited. All patients' baseline characteristics, risk factors, laboratory results, cardiovascular disease history, and medication use history were collected preoperatively. Histopathologic features within the vulnerable plaques were analyzed postoperatively. Risk factors for plaque vulnerability were assessed by univariate and multivariate analyses with adjustment for potential confounders. A total of 128 carotid plaques were removed during the carotid endarterectomy. On multivariate analysis, hypertension (odds ratio [OR] 5.971, 95% confidence interval [CI] 1.959−18.203, P = 0.002) and dyslipidemia (OR 3.822, 95% CI 1.317−11.089, P = 0.014) were independently associated with plaque vulnerability. Hypertension was independently associated with the presence of a ruptured fibrous cap (OR 6.122, 95% CI 2.318−16.166, P < 0.001), intraplaque hemorrhage (OR 3.535, 95% CI 1.551−8.055, P = 0.003), and a large lipid core (OR 2.335, 95% CI 1.053−5.180, P = 0.037). The incidence of having a large lipid core was increased by 3.216-fold in patients with dyslipidemia (95% CI 1.409−7.340, P = 0.006). When the multivariate analysis was restricted to symptomatic patients, hypertension (OR 5.005, 95% CI 1.294−19.350, P = 0.020) was the most significant risk factor associated with vulnerable plaque. The composition heterogeneity in the atherosclerotic plaque was significantly correlated to specific cardiovascular risk factors. [ABSTRACT FROM AUTHOR]

To assess the cerebral hemodynamic data associated with transient cerebral hemodynamic disturbance (TCHD), including cerebral hyperperfusion syndrome (CHS) and watershed shift ischemia (WSI), by whole-brain (WB) computed tomography perfusion (CTP) before and after revascularization for ischemic moyamoya disease. A total of 115 consecutive patients with ischemic moyamoya disease underwent revascularization. All patients underwent WB-CTP 24 hours before operation and on the day of onset of TCHD and 6 months after revascularization. The volumes of delay time (DT) >3 seconds and mismatch and relative cerebral blood flow <30% were calculated in 3 time points. Of the 115 patients, 18 115 had TCHD, comprising 10 with CHS and 8 with WSI. Compared with the brain volume of DT >3 seconds before revascularization, the volume decreased significantly (P < 0.05) on the day of CHS. The volume of mismatch in 3 time points indicated no significant differences (P > 0.05). The volume of relative cerebral blood flow <30% showed obvious differences of significance among 10 patients with CHS (P < 0.05) at 3 time points. In the WSI group, the volume of DT >3 seconds, mismatch, and DT >3 seconds showed significant differences, relatively (P < 0.05), at 3 time points. At the time of onset of TCHD, DT >3 seconds and mismatch in the CHS group were dramatically lower than those in the WSI group (P < 0.05). DT >3 seconds in the no-TCHD group showed significant differences (P < 0.05) at 3 time points. WB-CTP could be used to assess the cerebral hemodynamic characteristics before and after revascularization. DT >3 seconds and mismatch played important roles in evaluating distinct features of TCHD. [ABSTRACT FROM AUTHOR]

Very small intracranial aneurysms (VSIAs) are challenging to treat because aneurysm tearing and clip slippage can occur during neurosurgical clipping. In this study, we introduce and share our experience with cotton-assisted clipping of VSIAs. We retrospectively analyzed the data of 20 patients with 24 VSIAs treated with cotton-assisted clipping between February 2008 and December 2014 in the Neurosurgery Departments of the First Affiliated Hospital, Soochow University and Taizhou People's Hospital. During surgery, 2 aneurysm necks were torn. To treat the tears, we wrapped rectangular cotton pads around the parental arteries at the site of rupture. The remaining 22 aneurysms were clipped after being wrapped in cotton pads. The 2 aneurysm ruptures were successfully repaired with cotton-assisted clipping. In the remaining 22 aneurysms, no cases of aneurysm clip slippage or aneurysm rupture occurred. Patients were followed up on average for 59.0 months (range, 30–113 months). Of the 20 patients, the 16 patients with preoperative Hunt–Hess grades of 1–3 recovered well after the surgery (Glasgow Outcome Scale [GOS] score, 5). Of the 4 patients with Hunt–Hess grades of 4–5, 3 had a good recovery (GOS scores, 4–5), and 1 patient died of heart disease 6 months after being discharged from the hospital; this patient had a GOS score of 4 at the time of discharge. Cotton-assisted clipping could prevent aneurysm clip slipping and aneurysm rupture and facilitate the repair of aneurysm neck tears. This technique is a useful alternative therapy for VSIAs. [ABSTRACT FROM AUTHOR]

Objective: Intraplaque hemorrhage (IPH) and ulceration of carotid atherosclerotic plaques have been associated with vulnerability while calcification has been conventionally thought protective. However, studies suggested calcification size and location may increase plaque vulnerability. This study explored the association between calcium configurations and ulceration with IPH.Methods: One hundred thirty-seven consecutive symptomatic patients scheduled for carotid endarterectomy were recruited. CTA and CTP were performed prior to surgery. Plaque samples were collected for histology. According to the location, calcifications were categorized into superficial, deep and mixed types; according to the size and number, calcifications were classified as thick and thin, multiple and single.Results: Seventy-one plaques had IPH (51.8%) and 83 had ulceration (60.6%). The appearance of IPH and ulceration was correlated (r = 0.49; p < 0.001). The incidence of multiple, superficial and thin calcifications was significantly higher in lesions with IPH and ulceration compared with those without. After adjusting factors including age, stenosis and ulceration, the presence of calcification [OR (95% CI), 3.0 (1.1-8.2), p = 0.035], multiple calcification [3.9 (1.4-10.9), p = 0.009] and superficial calcification [3.4 (1.1-10.8), p = 0.001] were all associated with IPH. ROC analysis showed that the AUC of superficial and multiple calcifications in detecting IPH was 0.63 and 0.66, respectively (p < 0.05). When the ulceration was combined, AUC increased significantly to 0.82 and 0.83, respectively. Results also showed that patients with lesions of both ulceration and IPH have significantly reduced brain perfusion in the area ipsilateral to the infarction.Conclusions: Superficial and multiple calcifications and ulceration were associated with carotid IPH, and they may be a surrogate for higher risk lesions.Key Points: • CTA-defined superficial and multiple calcifications in carotid atherosclerotic plaques are independently associated with the presence of intraplaque hemorrhage. • The combination of superficial and multiple calcifications and ulceration is highly predictive of carotid intraplaque hemorrhage. • Patients with lesions of both ulceration and intraplaque hemorrhage have significantly reduced brain perfusion in the area ipsilateral to the infarction. [ABSTRACT FROM AUTHOR]

In this study, the effect of defects on fracture toughness in different directions was investigated. Two diamond films with a diameter of 122 mm and as-deposited thicknesses of 2.2 and 1.5 mm, respectively, were deposited by DC arc plasma jet chemical vapor deposition. To accurately obtain the fracture toughness, the films were ground and polished to 1.6 and 0.8 mm, respectively. The results indicate that many defects, including pores, are introduced into the films during the growth process, particularly on the side close to the growth surface in thicker film. The size of pores reaches micrometres, which affects the fracture toughness under loading in different directions. Due to the minimum grain size, both films exhibit a maximum toughness of 8.2 and 10.0 MPa·m1/2, respectively, with growth-surface cracks. For the thinner sample, the maximum value is followed by that of the edge-surface cracks. As the grain size of the edge surface falls between that of the growth surface and that of the nucleation surface, the results indicate that fracture toughness is affected by grain size. However, the number of pores near the growth side increases when the thickness exceeds 0.8 mm. Pores reduce the toughness, resulting in the minimum fracture toughness (6 MPa·m1/2) of the thicker diamond film with edge-surface laser cracks. The sample with an edge-surface sharp pre-crack has a similar fracture toughness of 5.6 MPa·m1/2. This study provides guidance for selecting the applied load direction. • Two thick diamond films with thicknesses 2.18 and 1.48 mm were deposited. • Fracture toughnesses of the diamond films in three directions were investigated. • Numerous pores were formed in the diamond films during orientation growth. • Due to the effect of pores, the toughness values among three directions differ. [ABSTRACT FROM AUTHOR]

[Display omitted] • A high channel hole mobility of 200 cm2V−1s−1 was achieved in C-Si interface (1 1 1) diamond MOSFETs. • The C-Si interface provides the MOSFETs with an excellent normally-off operation. • The advantage of boron doping in (1 1 1) diamond provides a large maximum current density. • The anatomically flat and strain-free interface between the (1 1 1) diamond and SiO 2 film was confirmed by HRTEM. • The existence of C-Si bonds at the interface was proved by EELS and XPS. In this paper, a diamond-silicon (C-Si) interface was constructed on a (1 1 1) diamond substrate by annealing the SiO 2 gate insulator in a reductive atmosphere. Corresponding metal-oxide-semiconductor field effect transistors (MOSFETs) with a C-Si conductive channel were fabricated. The MOSFETs demonstrate excellent normally-off operation with a high threshold voltage (V th) of −16 V and a high current density of −167 mA/mm, with a gate length (L G) of 4 μm. The channel hole mobility (μ FE) reaches 200 cm2V−1s−1 with a L G of 10 μm, and the interface state density (D it) is as low as 3.8 × 1011 cm−2 eV−1. The high-resolution transmission electron microscopy (HRTEM) image displays a coherent and strain-free interface between the SiO 2 film and (1 1 1) diamond, which ensures a high μ FE and low D it in the MOSFETs. The interface is dominated by C-Si bonds, which are confirmed by atomic-scale electron energy loss (EELS) quantification, spectroscopic characterization, and X-ray photoelectron spectroscopy (XPS). These results demonstrate that diamond, directly combined with SiO 2 , is ideal for implementation in power devices. [ABSTRACT FROM AUTHOR]

In order to realize the practical use of diamond as a semiconductor material, large-area single-crystal diamond wafers with uniform quality are required. Mosaic growth is an effective method to produce inch-grade single-crystal diamonds. However, the quality of the wafer is limited by the junction interface seriously, because cracking occurs easily due to the high internal stress. In this paper, the repetition growth method was adopted to grow mosaic splicing single-crystal diamond without polycrystalline diamond interface. The high-quality single crystal diamond slices were reduplicated by microwave plasma chemical vapor deposition (MPCVD). The substrates were obtained by cutting a piece of CVD diamond along a plane perpendicular to 〈001〉 (with a (100)-oriented surface). The evolution of the growth characteristics around the junction of the substrates at different stages was studied. The results show that the surface of the epitaxial layers gradually evolves from blurry terraces to a regular well-ordered step flow. When the substrates have the same deviation direction and the off-direction angles are within 3°, the junction of the substrates can connect smoothly. Raman mapping shows that there is a mixture of tensile stress and compressive stress near the junction. As the thickness of the epitaxial layer increases from 280 μm to 560 μm, the range of tensile stress near the joint area expands from 85 μm to 150 μm, the maximum tensile stress increases from 0.08 GPa to 0.16 GPa. In addition, the value of FWHM in the X-ray rocking curve is less than 2.80 cm−1 around the junction, which indicates good crystal quality. [Display omitted] • The evolution of growth characteristics around the junction in the mosaic diamond was studied. • The mosaic boundary evolved from blurry terraces to a well-ordered step flow and finally connected. • The lowest value of tensile stress near the joint area was reported as the film thickness increased. • The larger FWHM of Raman peak around the junction is caused by the increased tensile stress. • The "inherit" effect of NV content of the epitaxial layer was observed for the corresponding substrate. [ABSTRACT FROM AUTHOR]