A High-Resolution Time Reversal Method for Target Localization in Reverberant Environments.

Reverberation in real environments is an important factor affecting the high resolution of target sound source localization (SSL) methods. Broadband low-frequency signals are common in real environments. This study focuses on the localization of this type of signal in reverberant environments. Because the time reversal (TR) method can overcome multipath effects and realize adaptive focusing, it is particularly suitable for SSL in a reverberant environment. On the basis of the significant advantages of the sparse Bayesian learning algorithm in the estimation of wave direction, a novel SSL is proposed in reverberant environments. First, the sound propagation model in a reverberant environment is studied and the TR focusing signal is obtained. We then use the sparse Bayesian framework to locate the broadband low-frequency sound source. To validate the effectiveness of the proposed method for broadband low-frequency targeting in a reverberant environment, simulations and real data experiments were performed. The localization performance under different bandwidths, different numbers of microphones, signal-to-noise ratios, reverberation times, and off-grid conditions was studied in the simulation experiments. The practical experiment was conducted in a reverberation chamber. Simulation and experimental results indicate that the proposed method can achieve satisfactory spatial resolution in reverberant environments and is robust.

Functional and Degradable Polyester-co-polyethers from CO2, Butadiene, and Epoxides.

Carbon dioxide (CO2), as a renewable and nontoxic C1 feedstock, has been recognized as an ideal comonomer to prepare sustainable materials. In this regard, substantial focus has been dedicated to the ring-opening copolymerization of CO2 and epoxides, which results in the creation of aliphatic polycarbonates in most cases. Here, we report an unprecedented strategy to synthesize functional and degradable polyester-co-polyethers from CO2, butadiene, and epoxides via a CO2/butadiene-derived δ-valerolactone intermediate (EVP). Utilizing a chromium salen complex as the catalyst, the copolymerization of EVP and epoxides was successfully achieved to produce CO2/butadiene/epoxide terpolymers. The obtained polyester-co-polyethers with varied 39-93 mol % EVP content (equal to 18-28 wt % CO2 incorporation) show high thermal stability, tunable glass-transition temperatures, on-demand functionality, and good chemical degradability. This method extends the potential to access functional CO2-based polymers.

Pleosmaranes A-R, Isopimarane and 20-nor Isopimarane Diterpenoids with Anti-inflammatory Activities from the Mangrove Endophytic Fungus Pleosporales sp. HNQQJ-1.

Pleosmaranes A-R (1-18), 18 new isopimarane-type diterpenoids, together with four known analogs (19-22), were isolated from the mangrove endophytic fungus Pleosporales sp. HNQQJ-1. Their structures and absolute configurations were established by analysis of their spectroscopic data and electronic circular dichroism (ECD) calculations. Compounds 1-9 possess an unusual aromatic B ring and a 20-nor-isopimarane skeleton. Compounds 15-17 contain a unique 2-oxabicyclo[2.2.2]octane moiety. Compound 18 features an unexpected 2-oxabicyclo[3.2.1]octane moiety. Compounds 8 and 12 exhibited a moderate inhibitory effect against LPS-induced NO production, with IC50 values of 19 and 25 µM, respectively.

Cytosporones with Anti-Inflammatory Activities from the Mangrove Endophytic Fungus Phomopsis sp. QYM-13.

Six previously undescribed cytosporone derivatives (phomotones A-E (1-5) and phomotone F (13)), two new spiro-alkanol phombistenes A-B (14-15), and seven known analogs (6-12) were isolated from the mangrove endophytic fungus Phomopsis sp. QYM-13. The structures of these compounds were elucidated using spectroscopic data analysis, electronic circular dichroism (ECD), and 13C NMR calculations. Compound 14 features an unprecedented 1,6-dioxaspiro[4.5]decane ring system. All isolates were evaluated for their inhibitory effect on nitric oxide (NO) in LPS-induced RAW264.7 cells. The results showed that compounds 1, 6, 8, and 11 exhibited potent bioactivities by comparing with positive control. Then, compound 1 displayed the anti-inflammatory effect by inhibiting the MAPK/NF-κB signaling pathways. Molecular docking further revealed the possible mechanism of compound 1 interaction with ERK protein.

Predictors and outcome of malignant cerebral edema after successful reperfusion in anterior circulation stroke.

BACKGROUND AND OBJECTIVE: Risk factors and predictors of malignant cerebral edema (MCE) after successful endovascular thrombectomy (EVT) were not fully explored. This study aimed to evaluate the incidence and risk factors of MCE after successful reperfusion. METHODS: We retrospectively analyzed consecutive ischemic stroke patients who underwent EVT in our institution from November 2015 to April 2022. Patients who failed to achieve successful reperfusion (modified thrombolysis in cerebral infarction [mTICI]<2b) were excluded. Based on multivariate logistic models, the best-fit monogram was established. The discriminative performance was assessed by the receiver operating characteristics curve (ROC). RESULTS: A total of 307 patients were included and 48 (15.6%) were diagnosed with MCE after successful reperfusion. Patients with MCE after successful reperfusion had a lower 3-month favorable outcome (15.2% versus 59.6%; p<0.001), a lower 3-month good outcome (17.4% versus 68.4%; p<0.001), and a higher rate of mortality at 3-month (54.3% versus 8.8%; p<0.001) compared with patients without MCE. Predictors of MCE after successful reperfusion included admission glucose level, baseline National Institutes of Health Stroke Scale (NIHSS) score, stroke etiology, occlusion site and puncture-to-reperfusion (PTR) time>120 min. The area under the curve (AUC) of the nomogram was 0.805 (95% CI, 0.756-0.847). CONCLUSIONS: MCE after successful reperfusion is associated with poor outcome and mortality. A nomogram containing admission glucose level, baseline NIHSS score, stroke etiology, occlusion site and PTR time>120 min may predict the risk of MCE after successful reperfusion in patients with acute ischemic stroke and treated successfully with EVT.

Microwave photonics broadband unambiguous frequency measurement based on a Sagnac loop and a linear optical filter.

We propose an instantaneous frequency measurement (IFM) scheme featured with unambiguous measurement utilizing a Sagnac loop with an embedded bi-directional phase modulator and an optical filter with a linear frequency response. The frequency of the microwave signal to be measured is instantaneously estimated by calculating an amplitude comparison function (ACF) of photocurrents from the upper and lower branches of the proposed structure. Compared to previous IFM schemes, the ACF in the proposed scheme is monotonic, by which the frequency of the unknown microwave signal can be uniquely confirmed without ambiguity. Only one laser source and a phase modulator are needed, which simplifies the measurement system. In addition, the monotonous ACF can guarantee measurement accuracy in a wide range, from low frequency to high frequency. The IFM system has robustness in optical and RF power shifts. Simulation results show that frequency measurement over the range of 30 GHz with a measurement error of 0.4 GHz is achieved.

Guillain-Barré syndrome and hemophagocytic syndrome heralding the diagnosis of diffuse large B cell lymphoma: A case report.

BACKGROUND: Central nervous system (CNS) lesions and peripheral neuropathy are rare among patients with non-Hodgkin's lymphoma (NHL). Lymphomatous infiltration or local oppression usually accounts for CNS or peripheral nerve lesions. The incidence of peripheral neuropathy was 5%. Guillain-Barré syndrome (GBS) is rare and may occur in less than 0.3% of patients with NHL. Hemophagocytic syndrome (HPS) is a rare complication of NHL. It has been reported that 1% of patients with hematological malignancies develop HPS. Diffuse large B-cell lymphoma (DLBCL) combined with GBS has been reported in 10 cases. CASE SUMMARY: We report the case of a 53-year-old man who was initially hospitalized because of abnormal feelings in the lower limbs and urinary incontinence. He was finally diagnosed with DLBCL combined with GBS and HPS after 16 d, which was earlier than previously reported. Immunoglobulin pulse therapy, dexamethasone, and etoposide were immediately administered. The neurological symptoms did not improve, but cytopenia was relieved. However, GBS-related clinical symptoms were relieved partially after one cycle of rituximab - cyclophosphamide, hydroxydaunorubicin, vincristine, and prednisone (R-CHOP) chemotherapy and disappeared after six cycles of R-CHOP. CONCLUSION: GBS and HPS heralding the diagnosis of Epstein-Barr virus DLBCL are rare. Herein, we report a rare case of DLBCL combined with GBS and HPS, and share our clinical experience. Traditional therapies may be effective if GBS occurs before lymphoma is diagnosed. Rapid diagnosis and treatment of DLBCL are crucial.

Venous Flow Profiles on Perfusion CT are Associated with Futile Recanalization After Thrombectomy.

Background and Purpose: Robust venous outflow (VO) reflects favourable tissue reperfusion in acute ischaemic stroke (AIS) patients with large vessel occlusion (LVO). We aimed to investigate the association of the venous outflow profile on computed tomographic perfusion (CTP) and futile recanalization in anterior circulation AIS patients with LVO after thrombectomy. Methods: This was a retrospective study of consecutive AIS patients due to anterior circulation LVO who underwent CTP before thrombectomy. Patients who achieved successful recanalization defined as a modified Thrombolysis in Cerebral Infarction (mTICI) score of 2b or 3 after thrombectomy were included. Based on the venous time-intensity curve of CTP, the peak time of venous outflow (PTV), total venous outflow time (TVT), and difference value of arteriovenous peak time (D-value) were recorded. A modified mRS score of 3-6 at 3 months was regarded as futile recanalization (FR). Logistic regression analysis was applied to assess risk factors for FR. We used receiver operating characteristic curves (ROCs) to evaluate the predictive value of venous outflow time parameters based on VO for FR. Results: Eighty patients were included; 35 (43.8%) achieved good functional outcomes, and 45 (56.3%) had unfavourable functional outcomes, that is, FR. Adjusting confounding factors, binary stepwise logistic regression analysis showed that delayed PTV was independently associated with FR (odds ratio, 1.374 [95% CI, 1.093-1.726], P = 0.007). ROCs indicated that PTV effectively predicted unfavourable outcomes at 3 months (area under the curve (AUC) = 0.729, p< 0.001). The combined model was a powerful predictor of FR with an AUC of 0.824 and a cut-off value of 0.631 (p< 0.001). Conclusion: Delayed PTV is independently related to FR in anterior circulation AIS patients with LVO achieving successful recanalization after thrombectomy. Our results highlight that the time of VO may be a potential marker for FR.

Cystatin C predicts futile recanalization in patients with acute ischemic stroke after endovascular treatment.

BACKGROUND: A previous study reported that cystatin C was related to acute ischemic stroke. The association between cystatin C and the clinical outcome in acute ischaemic stroke patients with successful recanalization after endovascular thrombectomy has rarely been reported. This study aimed to evaluate the association between cystatin C and futile recanalization in AIS patients who underwent endovascular thrombectomy. METHODS: We carried out a retrospective study of acute ischaemic stroke patients with anterior circulation proximal arterial occlusion who achieved complete arterial recanalization after mechanical thrombectomy from May 2017 to April 2020. The patients with complete recanalization were divided into a useful recanalization group and a futile recanalization group according to their 3-month modified Rankin scale score. FR was defined as a modified mRS score of 3-6 at 3 months. Logistic regression analysis was used to identify the risk factors for FR. Receiver operating characteristic curves were used to assess the predictive value of cystatin C for FR. RESULTS: Of 241 patients, 125 underwent futile recanalization and 116 underwent useful recanalization. Baseline serum cystatin C levels were higher in the futile recanalization group than in the useful recanalization group. After adjustment for potential confounding factors, multivariable adjusted regression models showed that cystatin C was an independent predictor of futile recanalization (odds ratio, 4.111 [95% CI 1.427-11.840], P = 0.009). Receiver operator characteristic (ROC) curve analysis indicated that the model combining cystatin C with other factors model effectively predicted unfavourable outcomes at 3 months (area under the curve = 0.782, p < 0.01). CONCLUSIONS: A higher level of cystatin C is associated with unfavourable outcomes at 3 months in anterior circulation acute ischaemic stroke patients with endovascular thrombectomy.

CCCTC-binding factor transcriptionally regulates Galectin-7 and activates the JNK/STAT3 axis to aggravate bronchial epithelial cell injury.

OBJECTIVE: Studies have shown that the expression of CCCTC-binding factor (CTCF) is significantly upregulated in the airway epithelial cells of asthmatic patients, suggesting that CTCF may play an important role in the progression of asthma. MATERIAL/METHODS: Human bronchial epithelial cells BEAS-2B were stimulated with transforming growth factor-ß1 (TGF-ß1) at a concentration of 10 ng/ml, and CTCF overexpression plasmid and CTCF small interfering RNA were transfected into the cells. The proliferation, apoptosis, inflammatory factor secretion, and airway remodeling marker protein expression of injured cells were detected. We bidirectionally regulated Galectin-7 expression in TGF-ß1-induced BEAS-2B cells and overexpress CTCF, while interfering with Galectin-7 to further explore the regulatory effect of CTCF on Galectin-7. We introduced SP600125, a c-Jun N-terminal kinase c-Jun (JNK) pathway inhibitor, to investigate whether CTCF affects asthma progression through the JNK pathway. RESULTS: The expression of CTCF in BEAS-2B cells induced by TGF-ß1 was significantly upregulated, interfering with CTCF expression promoted cell proliferation, inhibited apoptosis, reduced inflammatory factors secretion, and decreased the expression of airway remodeling marker protein. Luciferase reporter gene analysis and chromatin immunoprecipitation verified that CTCF directly bound to Galectin-7 promoter. The effect of Galectin-7 on cells is consistent with the effect of CTCF on cells. The regulatory effect of CTCF on injured cells was indeed mediated by activation of the JNK/STAT3 axis. CONCLUSIONS: CTCF transcriptionally regulated Galectin-7 and activated JNK/STAT3 axis to aggravate bronchial epithelial cell injury.

Asymmetric Deoxygenative Alkynylation of Tertiary Amides Enabled by Iridium/Copper Bimetallic Relay Catalysis.

A variety of inert tertiary amides have been successfully transformed into synthetically important chiral propargylamines in high yields with good to excellent enantioselectivities via a relayed sequence of Ir catalyzed partial reduction and Cu/GARPHOS catalyzed asymmetric alkynylation with terminal alkynes. The reaction was readily extended to some drug molecules and the transformations of representative products have been demonstrated, thus attesting the practical utilities and the robust nature of the protocol.

Degradation of petroleum hydrocarbons by embedding immobilized crude oil degrading bacteria.

In this study, the removal effect of free and immobilized bacteria on crude oil was determined. Sodium alginate and polyvinyl alcohol were used as embedding agent, and ramie was modified as an adsorbent to immobilize free bacteria. The conditions for preparing immobilized pellets were optimized using the response surface method, and the best combination was simulated and obtained by Design-Expert 8.0. The best degradation rate of immobilized bacteria was 75.52%. The degradation by free bacteria and immobilized bacteria showed that the selected microorganisms had a good degradation effect on petroleum hydrocarbons.

Two-step system for image receiving in OAM-SK-FSO link.

Turbulence resistance is a significant research area for orbital angular momentum shift keying-based free space optical communication (OAM-SK-FSO). We put forward a two-step combinational system to receive high fidelity image data from the atmospheric turbulence (AT) channels. Firstly, the AT-detector-based multi-CNN (ATDM-CNN) demodulator is proposed which is very different from the traditional single-CNN (S-CNN) demodulator. The AT detector detects the AT strength and then an AT-determined CNN-based demodulator is activated to recognize the incident OAM modes. Sufficient numeral simulations compare the recognition rates of ATDM-CNN and S-CNN. The results indicate a tremendous improvement owing to the ATDM-CNN demodulator. Base on the ATDM-CNN's significant advantage in OAM recognition, the significant optimization of image data quality is possible in the further correction. As an option, the residual information errors are corrected by jointly using the rank-order adaptive median filter (RAMF) and the very-deep super-resolution (VDSR) network with minor information loss in severe ATs. The data increase resulting from RAMF-VDSR is tested. In conclusion, the proposed two-step system can provide a much higher quality of receiving image data in the OAM-SK-FSO link.

Metabolic Syndrome Predicts Poor Outcome in Acute Ischemic Stroke Patients After Endovascular Thrombectomy.

BACKGROUND AND AIMS: The metabolic syndrome (MetS) is believed to contribute to a higher probability of developing cardiovascular diseases. This study aimed to investigate whether MetS could predict the prognosis in ischemic stroke patients after endovascular thrombectomy (EVT). METHODS: Between January 2016 and September 2019, patients treated with EVT due to large vessel occlusions in anterior circulation were prospectively recruited. MetS was defined using the International Diabetes Federation criteria after admission. The primary outcome was a 3-month poor outcome (modified Rankin scale score of 3-6). Secondary outcomes included symptomatic intracranial hemorrhage (sICH) and mortality at 3 months. Multivariable logistic regression models were used to assess the relationship between MetS and clinical outcomes. RESULTS: A total of 248 patients were enrolled (mean age, 66.7 years; 37.5% female) and 114 (46.0%) met with the MetS criteria. The median National Institutes of Health Stroke Scale score was 15.0. There were 131 (52.8%) patients achieving the poor outcome at 3 months, among which 26 (10.5%) patients developed sICH. The mortality at 3 months was 19.0% (47/248). In multivariable analysis, MetS was significantly correlated to poor outcome (odds ratio [OR], 2.48; 95% confidence interval [CI], 1.29-4.78, P = 0.014). The risk for poor outcome was positively associated with the increased number of MetS components (OR 1.78; 95% CI 1.39-2.35, P = 0.001). No significant findings were found in the association of MetS with sICH and mortality. CONCLUSION: Our data demonstrated that MetS was associated with poor prognosis in acute ischemic patients treated with EVT.

Is intravenous thrombolysis safe for acute ischemic stroke patients taking warfarin with INR 1.9?: A case report.

INTRODUCTION: Intravenous thrombolysis is not suitable for patients undergoing oral anticoagulants therapy, with INR > 1.7 or PT > 15 s. We described a case of intravenous thrombolysis in a patient with INR 1.9. PATIENT CONCERNS: A 66-year-old female patient was diagnosed with acute appendicitis complicated with atrial fibrillation. Seven days after admission, the patient suffered mixed aphasia with right limb asthenia. The NIHSS score was 11 points. and early infarction and hemorrhagic manifestations were not found in the emergency head CT. Thirty minutes after the onset of symptoms, NIHSS of patient increased from 11 to 14, but the INR was 1.92. DIAGNOSIS: Acute ischemic stroke. INTERVENTIONS: The IT therapy was recommended and all the therapy related risks were explained to the patient's parents. Briefly, the patient was given rTPA 38.5 mg. In addition to intravenous thrombolysis, VitK1 40 mg was simultaneously administered. OUTCOME: The patient's symptoms of drowsiness were improved. After 24 hours, all symptoms were stabilized with NIHSS of 2 points, there was a slight language obstruction, and no hemorrhagic transformation in head CT. Three months later, the review showed MRS score of 0, and the patient could take care of herself in daily life. CONCLUSION: The clinical guidelines are still the main reference for guiding clinical practice, and the main thrombolytic standards and contraindications for treatment still need to be conformed. On this basis, for individualized patients, clinicians must accurately judge the cause of acute stroke, to make optimal choice, reduce disability and mortality, and improve quality of life of patients.

N-Protecting group tuning of the enantioselectivity in Strecker reactions of trifluoromethyl ketimines to synthesize quaternary α-trifluoromethyl amino nitriles by ion pair catalysis.

An enantioselective Strecker reaction to construct trifluoromethylated quaternary stereocenters with N-PMP and unexplored N-Boc trifluoromethyl ketimines catalyzed using an organophosphine dual-reagent catalyst has been developed. The enantioselectivities of the corresponding products with the same catalyst could be switched by using different N-protecting groups (N-PMP or N-Boc). The trifluoromethyl amino nitriles were obtained in high yield and high enantioselectivity in a short time and could be easily converted to a variety of useful trifluoromethyl-containing compounds.

Construction of a quaternary ammonium salt platform with different alkyl groups for antibacterial and biosensor applications.

An electrochemical platform was designed using biocompatible quaternary ammonium salts containing alkyl groups with different chain lengths as electrode materials for visible protein immobilization on a glassy carbon (GC) electrode. The electrode was constructed using a simple self-assembly method relying on the electrostatic interaction between negatively charged hemoglobin (Hb) and positively charged quaternary ammonium materials. The Hb/quaternary ammonium salts/GC assembly exhibited excellent catalytic and electrochemical activities. Additionally, the structure-function properties of the quaternary ammonium salts on the electrochemical behavior of Hb was systematically investigated for various alkyl chain lengths between monomer and polymeric structures. Meanwhile, the corresponding bactericidal activities of the monomers and related polymers were evaluated by determining the minimum bactericidal concentration (MBC), minimum inhibitory concentration (MIC), and inhibitory zone diameters against bacteria. The results of these studies demonstrated that the quaternary ammonium monomers not only immobilized more proteins, but also displayed better antibacterial activity as alkyl chain length increased. Moreover, polymers possessed higher antimicrobial activities than their monomeric counterparts. However, the efficiency of the direct electron transfer process and the antibacterial properties of long-chain polymers were limited because they were prone to aggregation and blistering. In summary, the present results provide convenient access to direct electrochemistry using an immobilized redox protein. Furthermore, the potential to use the obtained materials in the construction of third-generation electrochemical biosensors was evaluated.

Grafting Modification of the Reactive Core-Shell Particles to Enhance the Toughening Ability of Polylactide.

In order to overcome the brittleness of polylactide (PLA), reactive core-shell particles (RCS) with polybutadiene as core and methyl methacrylate-co-styrene-co-glycidyl methacrylate as shell were prepared to toughen PLA. Tert-dodecyl mercaptan (TDDM) was used as chain transfer agent to modify the grafting properties (such as grafting degree, shell thickness, internal and external grafting) of the core-shell particles. The introduction of TDDM decreased the grafting degree, shell thickness and the Tg of the core phase. When the content of TDDM was lower than 1.15%, the RCS particles dispersed in the PLA matrix uniformly-otherwise, agglomeration took place. The addition of RCS particles induced a higher cold crystallization temperature and a lower melting temperature of PLA which indicated the decreased crystallization ability of PLA. Dynamic mechanical analysis (DMA) results proved the good miscibility between PLA and the RCS particles and the increase of TDDM in RCS induced higher storage modulus of PLA/RCS blends. Suitable TDDM addition improved the toughening ability of RCS particles for PLA. In the present research, PLA/RCS-T4 (RCS-T4: the reactive core-shell particles with 0.76 wt % TDDM addition) blends displayed much better impact strength than other blends due to the easier cavitation/debonding ability and good dispersion morphology of the RCS-T4 particles. When the RCS-T4 content was 25 wt %, the impact strength of PLA/RCS-T4 blend reached 768 J/m, which was more than 25 times that of the pure PLA.