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Background Neurological recovery after endovascular treatment (EVT) for large vessel occlusion stroke often has diverse timelines. Understanding the temporal progression of functional independence after EVT, especially delayed functional independence (DFI) and highly delayed functional independence (HDFI), in patients who do not improve early is essential for prognostication and rehabilitation. We aimed to analyze the prevalence and predictors of DFI and HDFI after EVT in acute vertebrobasilar artery occlusions (VBAO). Methods Patients with VBAO who received EVT in China were retrospectively enrolled. Early functional independence (EFI) was defined as a modified Rankin Scale (mRS) score of 0-2 at discharge. The incidence and predictors of DFI (mRS score 0-2 at 90 days in non-EFI patients) and HDFI (mRS score 0-2 at 1 year in non-DFI patients) were analyzed. Results 2422 patients met the study criteria. EFI was observed in 20% (483) of patients. Among non-EFI patients, DFI was observed in 21% (395/1880). HDFI was observed in 13% (191/1439) of non-DFI patients. Younger age (P=0.006), lower pre-EVT National Institutes of Health Stroke Scale (NIHSS) score (P<0.001), higher posterior circulation-Alberta Stroke Program Early CT Score (PC-ASPECTS) (P=0.012), and absence of symptomatic intracranial hemorrhage (sICH) (P<0.001) were predictors of DFI. Predictors of HDFI were younger age (P<0.001) and lower pre-EVT NIHSS score (P<0.001). Conclusion A considerable proportion of patients have DFI and HDFI. The independent predictors of DFI were younger age, lower pre-EVT NIHSS score, higher PC-ASPECTS, and absence of sICH. Predictors of HDFI included younger age and lower pre-EVT NIHSS score. [ABSTRACT FROM AUTHOR]

Background Few studies have focused on the effect of systemic inflammation in vertebrobasilar artery occlusion (VBAO). The aim of this study was to investigate the relationship between inflammatory indicators and the prognosis of VBAO patients receiving endovascular treatment (EVT). Method Patients with VBAO who were treated with EVT within 24 hours of the estimated occlusion time were included in this study. Multivariate logistic regression and elastic net regularization were performed to analyze the effects of inflammatory indicators on the prognosis of patients with VBAO. The primary outcome was unfavorable outcome (a modified Rankin Scale score of 4-6) at 90 days. Secondary outcomes included symptomatic intracranial hemorrhage, in-hospital mortality, 90 day mortality, 1 year unfavorable outcome, and mortality. Results 560 patients were included in the study. Multivariate analysis showed that white blood cells (W), neutrophils (N), neutrophil to lymphocyte ratio (NLR), platelet to neutrophil ratio, platelet to white blood cell ratio, and NLR to platelet ratio were associated with the primary outcome. Elastic net regularization indicated that W, N, and NLR were the major inflammatory predictors of unfavorable outcome at 90 days. For long term prognosis, we found that the inflammatory indicators that predicted 1 year outcomes were consistent with those that predicted 90 day outcomes. Conclusion Inflammatory indicators, especially W, N, and NLR, were associated with moderate and long term prognosis of patients with VBAO treated with EVT. [ABSTRACT FROM AUTHOR]

Background To develop and validate a novel tool for predicting the development of malignant brain edema (MBE) in large vessel occlusion stroke patients after endovascular thrombectomy (EVT). Methods We used a prospectively registered population of EVT patients from three comprehensive stroke centers. The population was randomly divided into two subsets (7:3): a training cohort and an internal validation cohort. External validation was performed using the Endovascular Treatment for Acute Anterior Circulation Ischemic Stroke Registry in China (ACTUAL) database. MBE was defined as (1) hypodense parenchyma in at least 50% of the middle cerebral artery and signs of local brain swelling, and (2) a midline shift of ≥5 mm at the septum pellucidum or pineal gland with obliteration of the basal cisterns. The model was constructed using logistic regression analysis. The performance of the model was examined in terms of discrimination and calibration. Results After adjusting for other confounders, baseline National Institutes of Health Stroke Scale (NIHSS) and Alberta Stroke Program Early CT (ASPECT) scores, a clinical history of hypertension, collateral status, intravenous thrombolysis before thrombectomy, fasting blood glucose, reperfusion status, and occlusion site were found to be independent predictors of MBE. These variables were combined to create the ACORNS grading scale. The areas under the curve in receiver operating curve analysis were 0.850 (95% CI 0.816 to 0.884), 0.874 (95% CI 0.821 to 0.926), and 0.785 (95% CI 0.740 to 0.829) for the training, internal validation, and external validation cohorts, respectively, indicating good discriminative performance in the validation cohorts. Conclusions The ACORNS grading scale is an accurate and easily applicable model for the prediction of the development of MBE after EVT. [ABSTRACT FROM AUTHOR]

Background The effects of secondary collateral compensation on outcomes remain unclear in patients with acute basilar artery occlusion (BAO) after endovascular treatment (EVT). This study aimed to evaluate the benefits of the anastomosis between the posterior inferior cerebellar artery (PICA) and the superior cerebellar artery (SCA) in BAO after EVT. Methods This cohort study was conducted using data from the Endovascular Treatment for Acute Basilar Artery Occlusion Study Registry. Patients with acute BAO and treated with EVT were included. The primary outcome was a modified Rankin Scale score of 0-2 at 90 days. Safety outcomes included symptomatic intracerebral hemorrhage (SICH) and 90-day mortality. Results Of the 646 patients included in the study, 196 (30.3%) patients had a PICA-SCA anastomosis. The PICA-SCA anastomosis was significantly associated with independent functional outcome at 90 days (67/196 (34.2%) vs 109/450 (24.2%), adjusted OR (aOR) 1.80 (95% CI 1.13 to 2.86), p=0.01) and was significantly associated with a decreased rate of SICH (40/442 (9.0%) vs 5/193 (2.6%), aOR 0.29 (95% CI 0.11 to 0.76), p=0.01). No significant difference was found between PICA-SCA anastomosis and 90-day mortality (219/450 (48.7%) vs 80/196 (40.8%), aOR 0.72 (95% CI 0.48 to 1.08), p=0.11). Subgroup analysis showed that the association between independent functional outcome and PICA-SCA anastomosis was strongest in patients with middle BAO (27/77 (35.1%) vs 22/118 (18.6%), aOR 2.64 (95% CI 1.13 to 6.15), p=0.03). Conclusions The PICA-SCA anastomosis is significantly associated with better functional outcomes in patients with acute BAO after EVT, especially in those with middle BAO. [ABSTRACT FROM AUTHOR]

Background Although recanalization can be successful, microcirculatory dysfunction is common in acute large vessel occlusive stroke (LVOS). We assessed the microcirculation time by postprocessing software and analyzed its impact on prognosis in patients treated with mechanical thrombectomy (MT). Methods Patients with acute LVOS treated with MT were retrospectively enrolled consecutively. We measured the time to peak (TTP) and cerebral circulation time (CCT) in regions of interest on digital subtraction angiography using syngo iFlow software (Siemens Healthineers, Forchheim, Germany). A modified Rankin score ≤2 at 90 days was defined as a favorable outcome. Logistic regression was used to analyze the effect of each time parameter on prognosis. Then, we included time parameters in the baseline model to construct receiver operating characteristic (ROC) curves to assess the predictive ability for prognosis. Results A total of 215 patients were finally included. Of them, 118 (54.9%) had a favourable outcome at 90 days. Multivariate analysis showed that the microvascular cerebral circulation time (mCCT) was significantly associated with poor outcomes (odds ratio (OR) 2.061, 95% confidence interval (CI) 1.414 to 3.005 p<0.001). The area under the ROC curve was significantly enhanced by including mCCT in the baseline model (0.859 vs 0.829, p=0.016, DeLong test). Conclusions The mCCT immediately after recanalization is a powerful predictive factor for 90-day functional prognosis. [ABSTRACT FROM AUTHOR]

Background and Purpose: Almost half of the patients exhibit futile recanalization after thrombectomy; however, the early postoperative predictors of futile recanalization remain unclear. We analyzed the relationship of post-thrombectomy ASPECTS (Post-ASPECTS) with 90-day prognosis and hemorrhagic transformation (HT). Methods: We collected data from patients with acute ischemic stroke (AIS) with anterior-circulation large vessel occlusion (ACLVO) who were treated via thrombectomy within 10 h in 3 hospitals. Successful endovascular recanalization was achieved (modified thrombolysis in cerebral ischemia [mTICI] 2b/3). Non-contrast computed tomography (NCCT) examination was performed immediately (within 1 h) after thrombectomy. Post-ASPECTS were scored based on the brain parenchymal hyperdensity in NCCT according to the ASPECTS scoring method. HT was defined according to the ECASS II classification criteria. Linear correlation, logistic regression, and receiver operating characteristic curve analyses were used to determine the influencing factors and best predictive value of 90-day prognosis, 90-day death, and HT. Results: A total of 231 patients were enrolled. The good prognosis rate, mortality rate, and HT rate were 57.1, 9.5, and 38.3%, respectively. The Post-ASPECTS affected poor prognosis, death, and HT. The best predictive value of Post-ASPECTS for poor prognosis, death, and HT was 7. The specificities of Post-ASPECTS for predicting HT, poor prognosis, and death were 87.6% (AUC, 0.811; P < 0.001), 87.1% (AUC, 0.768; P < 0.001), and 73.7% (AUC, 0.748; P < 0.001), with positive predictive values of 74.2, 75.7, and 21.4%, respectively. Conclusion: Post-ASPECTS predicted 90-day prognosis, death, and HT with high specificity and high positive predictive value in patients with AIS with ACLVO. Post-ASPECTS may be an ultra-early predictor of prognosis after thrombectomy. [ABSTRACT FROM AUTHOR]

Background: The long-term outcomes of acute large vessel occlusion (LVO) in anterior circulation treated by endovascular treatment (EVT) remains to be determined. The aim of this study was to assess the 5-year outcomes of patients with LVO who underwent EVT. Methods: This study was an observational, nationwide registry of consecutive patients with acute LVO who received EVT in 28 comprehensive stroke centers in China. The primary outcome was the proportion of favorable outcome [modified Rankin Scale score (mRS) 0-2] at 5 years. Secondary outcomes included proportions of patients with excellent outcome (mRS 0-1), all-cause mortality and risk of stroke recurrence at 5 years. Results: A total of 807 patients were included into the study and had 90-day follow-up data, 657 patients had 5-year follow-up data. At 90 days, 218 patients (27.0%) had an excellent outcome, 349 patients (43.2%) had a favorable functional outcome. 199 patients (24.7%) died. At 5 years, 190 patients (28.9%) had an excellent outcome, 261 patients (39.7%) had a favorable functional outcome, 317 patients (48.2%) died and 129 (28.2%) had stroke recurrence. Because of missing 5-year follow-up data, among available 269 patients who achieved functional independence at 90 days, 208 (77.3%) maintained favorable outcome, 19 (7.1%) had disability (mRS 3-5) and 42 (15.6%) died at 5 years. Furthermore, among available 189 patients with mRS 3-5 at 90 days, 53 (28.0%) patients achieved favorable functional outcome, 60 (31.7%) patients maintained unfavorable functional outcome and 76 (40.2%) patients died within 5 years. Multivariate analyses identified that younger age [odds ratio (OR): 0.96; 95% CI, 0.93-0.99; P = 0.009], lower mRS at 90 days (OR: 0.15; 95% CI, 0.10-0.23; P < 0.001) and absence of stroke recurrence (OR: 0.001; 95% CI, 0.000-0.006; P < 0.001) were significantly associated with favorable outcome at 5 years. Advanced age (OR: 1.06, 95% CI, 1.04-1.08; P < 0.001), higher mRS at 90 days (OR: 0.84; 95% CI, 0.73-0.98; P = 0.021) and atrial fibrillation (OR: 1.63; 95% CI, 1.02-2.60; P = 0.04) were independent factors for stroke recurrence. Conclusion: Our results indicated that the beneficial effect of EVT in patients with acute LVO can be sustained during the course of at least 5 years. Reducing the risk of stroke recurrence by anticoagulation for atrial fibrillation may be a crucial strategy to improve long-term outcome. [ABSTRACT FROM AUTHOR]

Background: Achieving rapid and complete vascular recanalization in patients with acute large vessel occlusion can significantly improve patients’ prognosis. Objective: We aimed to investigate the potential contribution of the first-pass effect (FPE) to the clinical outcome of patients with acute vertebrobasilar artery occlusion (VBAO). Methods: We retrospectively analyzed the data of patients who underwent endovascular thrombectomy (EVT) caused by VBAO in a multicentered retrospective registry dataset. FPE was defined as successful recanalization [modified thrombolysis in cerebral infarction (mTICI) 2b/3 as modified FPE (mFPE); mTICI 3 as true FPE (tFPE)] after one pass of the device without rescue therapy. The baseline characteristics and procedural and clinical outcomes were analyzed. Multivariate analysis was used to explore the predictors of FPE and the relationship between FPE and 90-day prognosis. Results: A total of 508 patients (age, 63.7±13.1years, male, 71.6%) were finally included, 29.9% (152/508) of whom achieved mFPE, and 21.1% (107/508) of whom achieved tFPE. FPE was significantly associated with improved clinical outcomes, regardless of mFPE [odds ratio (OR): 0.601, 95% confidence interval (CI): 0.370–0.977, p=0.040] and tFPE (OR: 0.547, 95% CI: 0.318–0.940, p=0.029). The use of contact aspiration, favorable collateral status, cardioembolic etiology, and basilar artery occlusion were statistically significant predictors of mFPE and tFPE, whereas hypertension was a negative predictor. Intravenous (IV) recombinant tissue plasminogen activator (rt-PA) prior to EVT was a positive predictor of mFPE but not of tFPE. Conclusion: FPE was associated with significantly favorable outcomes in EVT patients with VBAO. The predictors of FPE include infarct etiology, the site of occlusion, collateral status, EVT strategies, and IV rt-PA bridging strategies. [ABSTRACT FROM AUTHOR]

Background Malignant brain edema (MBE) is a devastating complication in ischemic stroke. Data on MBE in patients who have had mechanical thrombectomy (MT) are relatively scarce. Objective To investigate the incidence, predictors, and clinical outcomes of MBE in patients after MT. Methods We included 130 consecutive patients after MT caused by anterior circulation large vessel occlusion stroke, treated with MT. MBE was defined as a midline shift of ≥5 mm on the follow-up imaging within 72 hours after MT. Characteristics of patients at admission and details of treatment were collected. The 90-day modified Rankin scale score was used as a measure of functional outcomes. Results Of the 130 patients (age, 68.6±10.9 years; male, 50%), 35 (26.9%) patients developed MBE. The patients with MBE had a lower rate of functional independence (OR=7.831; 95% CI 1.731 to 35.427; p=0.008) and significantly higher mortality at 90 days (OR=7.958; 95% CI 2.274 to 27.848; p=0.001) than patients without MBE. In 104 (80%) patients with successful recanalization (modified Thrombolysis in Cerebral Infarction score of 2b--3), 24 (23.1%) patients exhibited MBE. After adjustment for confounding, ICA occlusion (OR=3.746; 95% CI 1.169 to 12.006; p=0.026) and worse collateral score (grade 1 vs grade 0: OR=0.727; 95% CI 0.192 to 2.753; p=0.638; grade 2 vs grade 0: OR=0.130; 95% CI 0.021 to 0.819; p=0.030) were significantly associated with the development of MBE, despite successful recanalization. Conclusions MBE after MT is not uncommon and was related to poor functional outcomes. Localization of a vessel occlusion and collateral status may play a role in the development of MBE. [ABSTRACT FROM AUTHOR]

In this letter, a graphene nanoflakes printed antenna is presented. Graphene nanoflakes conductive ink has been screenprinted on paper substrate and compressed to achieve the conductivity of 0.43 × 105 S/m. Low-profile meandered-line dipole antenna has been fabricated as a proof of concept due to its electrically small size and simple structure. The maximum gain is measured to be -4 dBi, the -10-dB bandwidth ranges from 984 to 1052 MHz (6.67%), and the radiation pattern is verified as being typical radiation patterns of a dipole-type antenna. The radiation efficiency is 32%. The measurement results reveal that graphene nanoflakes printed antenna can provide practically acceptable return loss, gain, bandwidth, and radiation patterns for midand short-range RFID, and sensing applications. Furthermore, screenprinting technique employed in this work is of extremely low cost and capable of producing antennas in mass production. [ABSTRACT FROM PUBLISHER]

In this paper, we demonstrate realization of printable radio frequency identification (RFID) antenna by low temperature processing of graphene ink. The required ultra-low resistance is achieved by rolling compression of binder-free graphene laminate. With compression, the conductivity of graphene laminate is increased by more than 50 times compared to that of as-deposited one. Graphene laminate with conductivity of 4.3 × 104S/m and sheet resistance of 3.8 Ω/sq (with thickness of 6 μm) is presented. Moreover, the formation of graphene laminate from graphene ink reported here is simple and can be carried out in low temperature (100 °C), significantly reducing the fabrication costs. A dipole antenna based on the highly conductive graphene laminate is further patterned and printed on a normal paper to investigate its RF properties. The performance of the graphene laminate antenna is experimentally measured. The measurement results reveal that graphene laminate antenna can provide practically acceptable return loss, gain, bandwidth, and radiation patterns, making it ideal for low cost printed RF applications, such as RFID tags and wearable wireless sensor networks. [ABSTRACT FROM AUTHOR]

This study presents an effective method to model, analyse and design graphene metasurface-based terahertz (THz) absorbers using equivalent circuit model approach. Broadband and tunable absorbers consisting of graphene metasurface and metal-backed dielectric layer have been designed based on the formulas derived from this approach and verified by full-wave electromagnetic simulation. By properly constructing the graphene metasurface, broadband absorption over 70% fraction bandwidth has been achieved, showing that graphene can provide a wideband absorption in the low THz spectrum. Furthermore, tunability of the graphene metasurface has also been investigated. It is demonstrated that the absorption peak frequencies can be tuned while maintaining the peak absorption unchanged, which is highly desirable for THz sensing applications. [ABSTRACT FROM AUTHOR]

This paper proposes a new type of graphene based tunable radar absorbing screen. The absorbing screen consists of Hilbert curve metal strip array and chemical vapour deposition (CVD) graphene sheet. The graphene based screen is not only tunable when the chemical potential of the graphene changes, but also has broadband effective absorption. The absorption bandwidth is from 8.9GHz to 18.1GHz, ie., relative bandwidth of more than 68%, at chemical potential of 0eV, which is significantly wider than that if the graphene sheet had not been employed. As the chemical potential varies from 0 to 0.4eV, the central frequency of the screen can be tuned from 13.5GHz to 19.0GHz. In the proposed structure, Hilbert curve metal strip array was designed to provide multiple narrow band resonances, whereas the graphene sheet directly underneath the metal strip array provides tunability and averagely required surface resistance so to significantly extend the screen operation bandwidth by providing broadband impedance matching and absorption. In addition, the thickness of the screen has been optimized to achieve nearly the minimum thickness limitation for a nonmagnetic absorber. The working principle of this absorbing screen is studied in details, and performance under various incident angles is presented. This work extends applications of graphene into tunable microwave radar cross section (RCS) reduction applications. [ABSTRACT FROM AUTHOR]

This paper presents a novel low-phase-noise and ultra-bandwidth LC-tank voltage-controlled oscillator (VCO). The work fully-integrated 5.8GHz VCO designed and simulated using 130-nm CMOS technology. Instead of using the conventional varactor in the tank design, a novel metal-oxidemetal (MOM) digital capacitor switching array (MOMDCSA) has been implemented with nMOS varactor is employed as an effective varactor bank. The proposed VCO-measured results at the centre frequency demonstrate a phase noise of -129.7 dBc/Hz and FOM of -198.38 dBc/Hz at 1MHz frequency offset. The VCO shows approximately 33% tuning range under a power consumption of 2.8mW. [ABSTRACT FROM AUTHOR]

This paper presents the design of a monolithic structure with dual-band quasi-elliptic frequency selective filtering responses. The frequency selective structure consists of a two-dimensional (2-D) array of cavities apertured with six ring slots. The transmission response is with a quasi-elliptic passband in lower frequency, and an elliptic passband in upper frequency. By placing transmission zeros near the passband edge, the proposed structure is characterized with high selectivity, rapid rolloff, and high separation between two passbands. Besides, the working principles and influence of the dimensional parameters are fully investigated with simulations and analysis, which is helpful to the design. In this design, five resonances and three transmission zeros are obtained with a simple unit by introducing coupling and phase controlling. This work will be meaningful in study of three dimensional frequency selective structures with high performance. [ABSTRACT FROM AUTHOR]