Preserving shape details of pulse signals for video-based blood pressure estimation.

In recent years, imaging photoplethysmograph (iPPG) pulse signals have been widely used in the research of non-contact blood pressure (BP) estimation, in which BP estimation based on pulse features is the main research direction. Pulse features are directly related to the shape of pulse signals while iPPG pulse signals are easily disturbed during the extraction process. To mitigate the impact of pulse feature distortion on BP estimation, it is necessary to eliminate interference while retaining valuable shape details in the iPPG pulse signal. Contact photoplethysmograph (cPPG) pulse signals measured at rest can be considered as the undisturbed reference signal. Transforming the iPPG pulse signal to the corresponding cPPG pulse signal is a method to ensure the effectiveness of shape details. However, achieving the required shape accuracy through direct transformation from iPPG to the corresponding cPPG pulse signals is challenging. We propose a method to mitigate this challenge by replacing the reference signal with an average cardiac cycle (ACC) signal, which can approximately represent the shape information of all cardiac cycles in a short time. A neural network using multi-scale convolution and self-attention mechanisms is developed for this transformation. Our method demonstrates a significant improvement in the maximal information coefficient (MIC) between pulse features and BP values, indicating a stronger correlation. Moreover, pulse signals transformed by our method exhibit enhanced performance in BP estimation using different model types. Experiments are conducted on a real-world database with 491 subjects in the hospital, averaging 60 years of age.

Electronic Structure Regulated Nickel-Cobalt Bimetal Phosphide Nanoneedles for Efficient Overall Water Splitting.

Transition metal phosphides (TMPs) have been widely studied for water decomposition for their monocatalytic property for anodic or cathodic reactions. However, their bifunctional catalytic activity still remains a major challenge. Herein, hexagonal nickel-cobalt bimetallic phosphide nanoneedles with 1-3 µm length and 15-30 nm diameter supported on NF (NixCo2-xP NDs/NF) with adjusted electron structure have been successfully prepared. The overall alkaline water electrolyzer composed of the optimal anode (Ni0.67Co1.33P NDs/NF) and cathode (Ni1.01Co0.99P NDs/NF) provide 100 mA cm-2 at 1.62 V. Gibbs Free Energy for reaction paths proves that the active site in the hydrogen evolution reaction (HER) is Ni and the oxygen evolution reaction (OER) is Co in NixCo2-xP, respectively. In the HER process, Co-doping can result in an apparent accumulation of charge around Ni active sites in favor of promoting HER activity of Ni sites, and ΔGH* of 0.19 eV is achieved. In the OER process, the abundant electron transfer around Co-active sites results in the excellent ability to adsorb and desorb *O and *OOH intermediates and an effectively reduced ∆GRDS of 0.37 eV. This research explains the regulation of electronic structure change on the active sites of bimetallic materials and provides an effective way to design a stable and effective electrocatalytic decomposition of alkaline water.

PFDNet: A Pulse Feature Disentanglement Network for Atrial Fibrillation Screening From Facial Videos.

Video-based Photoplethysmography (VPPG) can identify arrhythmic pulses during atrial fibrillation (AF) from facial videos, providing a convenient and cost-effective way to screen for occult AF. However, facial motions in videos always distort VPPG pulse signals and thus lead to the false detection of AF. Photoplethysmography (PPG) pulse signals offer a possible solution to this problem due to the high quality and resemblance to VPPG pulse signals. Given this, a pulse feature disentanglement network (PFDNet) is proposed to discover the common features of VPPG and PPG pulse signals for AF detection. Taking a VPPG pulse signal and a synchronous PPG pulse signal as inputs, PFDNet is pre-trained to extract the motion-robust features that the two signals share. The pre-trained feature extractor of the VPPG pulse signal is then connected to an AF classifier, forming a VPPG-driven AF detector after joint fine-tuning. PFDNet has been tested on 1440 facial videos of 240 subjects (50% AF absence and 50% AF presence). It achieves a Cohen's Kappa value of 0.875 (95% confidence interval: 0.840-0.910, P<0.001) on the video samples with typical facial motions, which is 6.8% higher than that of the state-of-the-art method. PFDNet shows significant robustness to motion interference in the video-based AF detection task, promoting the development of opportunistic screening for AF in the community.

Impact of Bivalirudin on Patients with Acute Coronary Syndrome Undergoing Rotational Atherectomy in Real-Life Setting: A Retrospective Cohort Study.

BACKGROUND: No evidence exists on the impact of bivalirudin in patients with the acute coronary syndrome undergoing rotational atherectomy. This study aimed to evaluate the impact of bivalirudin on patients with acute coronary syndrome undergoing rotational atherectomy. METHODS: This was a retrospective cohort study conducted in our hospital between January 2017 and December 2019. The study included patients with acute coronary syndrome undergoing rotational atherectomy. Furthermore, 2 cohorts were included in this study (bivalirudin cohort and control cohort unfractionated heparin). The primary end-point was in-hospital net adverse clinical events. The secondary endpoint was all-cause mortality at 23 months. RESULTS: The study included 157 patients with 33 (21.0%) in the bivalirudin cohort and 124 (79.0%) in the control cohort. Net adverse clinical events during hospitalization in the bivalirudin cohort were higher than that in the control cohort [9 (27.3%) vs. 14 (11.3%), P = .021]. However, there was no significant difference in all-cause mortality at 23 months between the 2 cohorts [25 (20.2%) vs. 10 (30.3%), P =.214]. After adjusting for potential confounders, the usage of bivalirudin was not associated with net adverse clinical event (odds ratio = 0.90; 95% CI: 0.18-4.45; P =.890), and the hazard ratio for all-cause mortality at 23 months was 1.01 (95% CI: 0.33-3.15; P =.983). CONCLUSION: Bivalirudin appears to exhibit a similar impact as unfractionated heparin on patients with acute coronary syndrome undergoing rotational atherectomy in real-life setting.

Nonepitaxial Electrodeposition of (002)-Textured Zn Anode on Textureless Substrates for Dendrite-Free and Hydrogen Evolution-Suppressed Zn Batteries.

Nontoxic and safe aqueous Zn batteries are largely restricted by the detrimental dendrite growth and hydrogen evolution of Zn metal anode. The (002)-textured Zn electrodeposition, demonstrated as an effective approach for solving these issues, is nevertheless achieved mainly by epitaxial or hetero-epitaxial deposition of Zn on pre-textured substrates. Herein, the electrodeposition of (002)-textured and compact Zn on textureless substrates (commercial Zn, Cu, and Ti foils) at a medium-high galvanostatic current density is reported. According to the systematic investigations on Zn nucleation and growth behaviors, this is ascribed to two reasons: i) the promoted nonepitaxial nucleation of fine horizontal (002) nuclei at increased overpotential and ii) the competitive growth advantages of (002)-orientated nuclei. The resulting freestanding (002)-textured Zn film exhibits significantly suppressed hydrogen evolution and prolonged Zn plating-stripping cycling life, achieving over 2100 mAh cm-2 cumulative capacity under a current density of 10 mA cm-2 and a high depth of discharge (DOD) of 45.5%. Therefore, this study provides both fundamental and practical insights into long-life Zn metal batteries.

Suppressing the Exacerbated Hydrogen Evolution of Porous Zn Anode with an Artificial Solid-Electrolyte Interphase Layer.

Rechargeable Zn batteries are widely studied as aqueous, safe, and environmentally friendly alternatives to Li-ion batteries. The 3D porous Zn anode has been extensively reported for suppressing Zn dendrite growth and accelerating the electrode kinetics. However, we demonstrate herein that the undesirable hydrogen evolution reaction (HER) is also exacerbated for porous Zn electrode. Therefore, a polytetrafluoroethylene (PTFE) coating is further applied on the porous Zn serving as the artificial solid-electrolyte interphase (SEI), which is demonstrated to effectively inhibit the hydrogen evolution and maintain the Zn plating kinetics. By utilizing the synergistic effects of the porous morphology and artificial SEI layer, better performances are obtained over porous Zn or bare Zn foil, including dendrite-free Zn plating/stripping up to 2000 h at 2 mA cm-2 and extended cycling in the Zn||V2O5 cell. This work suggests two complementary strategies for achieving simultaneously dendrite-free and side-reaction-suppressed Zn batteries.

Rapid Determination of Cellulose and Hemicellulose Contents in Corn Stover Using Near-Infrared Spectroscopy Combined with Wavelength Selection.

The contents of cellulose and hemicellulose (C and H) in corn stover (CS) have an important influence on its biochemical transformation and utilization. To rapidly detect the C and H contents in CS by near-infrared spectroscopy (NIRS), the characteristic wavelength selection algorithms of backward partial least squares (BIPLS), competitive adaptive reweighted sampling (CARS), BIPLS combined with CARS, BIPLS combined with a genetic simulated annealing algorithm (GSA), and CARS combined with a GSA were used to select the wavelength variables (WVs) for C and H, and the corresponding regression correction models were established. The results showed that five wavelength selection algorithms could effectively eliminate irrelevant redundant WVs, and their modeling performance was significantly superior to that of the full spectrum. Through comparison and analysis, it was found that CARS combined with GSA had the best comprehensive performance; the predictive root mean squared errors of the C and H regression model were 0.786% and 0.893%, and the residual predictive deviations were 3.815 and 12.435, respectively. The wavelength selection algorithm could effectively improve the accuracy of the quantitative analysis of C and H contents in CS by NIRS, providing theoretical support for the research and development of related online detection equipment.

Bioinspired soft electroreceptors for artificial precontact somatosensation.

Artificial haptic sensors form the basis of touch-based human-interfaced applications. However, they are unable to respond to remote events before physical contact. Some elasmobranch fishes, such as seawater sharks, use electroreception somatosensory system for remote environmental perception. Inspired by this ability, we design a soft artificial electroreceptor for sensing approaching targets. The electroreceptor, enabled by an elastomeric electret, is capable of encoding environmental precontact information into a series of voltage pulses functioning as unique precontact human interfaces. Electroceptor applications are demonstrated in a prewarning system, robotic control, game operation, and three-dimensional object recognition. These capabilities in perceiving proximal precontact events can lenrich the functionalities and applications of human-interfaced electronics.

VidAF: A Motion-Robust Model for Atrial Fibrillation Screening From Facial Videos.

Atrial fibrillation (AF) is the most common arrhythmia, but an estimated 30% of patients with AF are unaware of their conditions. The purpose of this work is to design a model for AF screening from facial videos, with a focus on addressing typical motion disturbances in our real life, such as head movements and expression changes. This model detects a pulse signal from the skin color changes in a facial video by a convolution neural network, incorporating a phase-driven attention mechanism to suppress motion signals in the space domain. It then encodes the pulse signal into discriminative features for AF classification by a coding neural network, using a de-noise coding strategy to improve the robustness of the features to motion signals in the time domain. The proposed model was tested on a dataset containing 1200 samples of 100 AF patients and 100 non-AF subjects. Experimental results demonstrated that VidAF had significant robustness to facial motions, predicting clean pulse signals with the mean absolute error of inter-pulse intervals less than 100 milliseconds. Besides, the model achieved promising performance in AF identification, showing an accuracy of more than 90% in multiple challenging scenarios. VidAF provides a more convenient and cost-effective approach for opportunistic AF screening in the community.

Application of serum exosomal hypoxia-inducible factor-1 alpha (HIF-1α) as potential circulating biomarker for bacterial peritonitis.

Bacterial peritonitis is a severe disease that diagnosis remains challenging for clinicians. Measuring biomarkers might be a rapid diagnostic method. The objective of this study was to analyze and evaluate the dynamic changes in HIF-1α concentration in serum exosomes during bacterial peritonitis. The pre-clinical application value of serum exosomal HIF-1α was evaluated via imipenem and cilastatin sodium (ICS) intervention in the bacterial peritonitis model. The new colorimetric method to quantitate dynamic expression changes of HIF-1α in serum exosomes during bacterial peritonitis was established by our team via using the gold seed-coated with aptamer-functionalized Au @ Au core-shell peroxidase mimic. The typical inflammatory cytokines of bacterial peritonitis were also measured. Following intramuscular administration with ICS, In-Vivo Xtreme imaging system was used to visualize abdominal infection extent. Meanwhile, HIF-1α concentration in rat serum exosomes and pro-inflammatory factors levels in serum were detected. The serum typical inflammatory cytokines levels were elevated in GFP-labeled E.coli induced bacterial peritonitis. The serum exosomal HIF-1α levels clearly increased at 12 h, reached the peak during 24-48 h, and then gradually decreased at 72 h. Following intramuscular administration with ICS, the abdominal infection extent, HIF-1α concentration in serum exosomes, and the serum pro-inflammatory factors levels were reduced at 24 h in GFP-labeled E. coli induced bacterial peritonitis model. The serum exosomal HIF-1α can be used as a biomarker in the early stage of bacterial peritonitis, which might provide the basic research in the pre-clinical for further predicting and monitoring the pathological process of bacterial peritonitis.

Electricity Generation and Self-Powered Sensing Enabled by Dynamic Electric Double Layer at Hydrogel-Dielectric Elastomer Interfaces.

The electric double layer (EDL) at liquid-solid interfaces is fundamental to many research areas ranging from electrochemistry and microfluidics to colloidal chemistry. Here, we demonstrate the electricity generation by mechanically modulating the EDL at the hydrogel-dielectric polymer interfaces. It is found that contact electrification between the hydrogel and the dielectric polymer could charge the dielectric polymer surface at first; the mechanical deformation of the pyramid-shaped hydrogel results in the periodic variation of the EDL area and capacitance, which then induces an alternative current in the external circuits. This mechano-to-electrical energy conversion mechanism is then utilized to construct soft stretchable self-powered pressure sensors by designing dynamic EDL at hydrogel-dielectric elastomer interfaces. The sensitivity is optimized to 1.40 kPa-1 in the low-pressure range of 31-300 Pa by increasing the elastomer roughness. Its antifreeze performance is also improved by adding ethylene glycol into the hydrogel. The capability in detecting subtle human activities is further demonstrated. This mechano-electrical energy conversion and the corresponding self-powered sensor can be widely applied in future soft electronics.

Rapid detection of cellulose and hemicellulose contents of corn stover based on near-infrared spectroscopy combined with chemometrics.

The feasibility of near-infrared spectroscopy (NIRS) combined with chemometrics for the rapid detection of the cellulose and hemicellulose contents in corn stover is discussed. Competitive adaptive reweighted sampling (CARS) and genetic simulated annealing algorithm (GSA) were combined (CARS-GSA) to select the characteristic wavelengths of cellulose and hemicellulose and to reduce the dimensionality and multicollinearity of the NIRS data. The whole spectra contained 1845 wavelength variables. After CARS-GSA optimization, the number of characteristic wavelengths of cellulose (hemicellulose) was reduced to 152 (260), accounting for 8.24% (14.09%) of all wavelengths. The coefficients of determination of the regression models for predicting the cellulose and hemicellulose contents were 0.968 and 0.996, the root mean square errors of prediction (RMSEPs) were 0.683 and 0.648, and the residual predictive deviations (RPDs) were 5.213 and 16.499, respectively. The RMSEP of the cellulose and hemicellulose regression models was 0.152 and 0.190 lower for CARS-GSA than for the full-spectrum, and the RPD was increased by 0.949 and 3.47, respectively. The results showed that the CARS-GSA model substantially reduced the number of characteristic wavelengths and significantly improved the predictive ability of the regression model.

Oligosaccharides from Polygonatum Cyrtonema Hua: Structural characterization and treatment of LPS-induced peritonitis in mice.

Fructooligosaccharide was isolated from Polygonatum Cyrtonema Hua (PFOS) for the first time. Structure characterized using FT-IR, MALDI-TOF-MS, NMR, AFM, and TEM, indicated that PFOS was graminan-type fructan with a degree of polymerization ranging from 5 to 10. A murine model of lipopolysaccharide (LPS)-induced peritonitis was used to evaluate the in vivo anti-inflammatory and lung protective efficacy of PFOS. The result shown that pretreatment with PFOS (1.0 mg/mL) in peritonitis-induced mice could significantly inhibit the level of pro-inflammatory cytokines (TNF-α, IL-1ß) in serum (P < 0.001), increase mice survival rate from 12.5 % to 54 % (P < 0.05), and alleviated lung injury through ameliorating the damage of the pulmonary cellular architecture and reducing inflammatory monocyte accumulation in lung tissue. This effect of oligosaccharides could explain the traditional usage of P. cyrtonema as a tonic medicine for respiratory problems and it could be used as a potential natural ingredient with anti-inflammatory activity.

Ultra-stretchable and healable hydrogel-based triboelectric nanogenerators for energy harvesting and self-powered sensing.

The next-generation multifunctional soft electronic devices require the development of energy devices possessing comparable functions. In this work, an ultra-stretchable and healable hydrogel-based triboelectric nanogenerator (TENG) is prepared for mechanical energy harvesting and self-powered sensing. An ionic conductive hydrogel was developed with graphene oxide and Laponite. as the physical cross-linking points, exhibiting high stretchability (∼1356%) and healable capability. When using the hydrogel as the electrode, the TENG can operate normally at 900% tensile strain, while the electrical output of the TENG can fully recover to the initial value after healing the damage. This hydrogel-based TENG is demonstrated to power wearable electronics, and is used as a self-powered sensor for human motion monitoring and pressure sensing. Our work shows opportunities for multifunctional power sources and potential applications in wearable electronics.

Predictive value of ACEF score for clinical prognosis of elderly patients with ST-segment elevation myocardial infarction after percutaneous coronary intervention.

BACKGROUND: To investigate the predictive value of the age, creatinine, and ejection fraction (ACEF) score for cardiac death in patients aged ≥75 years diagnosed with acute ST-segment elevation myocardial infarction (STEMI) at 1 month and 1 year after emergency percutaneous coronary intervention (PCI). METHODS: A total of 360 patients with STEMI undergoing emergency PCI in the Department of Cardiology of Anhui Provincial Hospital from January 2013 to April 2018 were consecutively recruited. The primary endpoint event was cardiac death at postoperative 1 month and 1 year. The ROC curve was utilized to evaluate ACEF scoring system and predict cardiac death rate. RESULTS: According to ACEF score upon admission, 360 patients were divided into low-to-intermediate risk group (n=80) with ACEF score of 0.99-1.27 (1.18±0.07) and high-risk group (n=280) with ACEF score of 1.28-4.14 (1.83±0.51). The age, left ventricular ejection fraction (LVEF), estimated glomerular filtration rate (eGFR), heart rate and the proportion of complete revascularization in the high-risk group were significantly higher than those in low-to-intermediate risk group (all P<0.05). The area under ROC curve for ACEF scoring system to predict cardiac death at 1 month and 1 year following PCI was 0.809 and 0.763, respectively. CONCLUSIONS: ACEF value upon admission can predict the cardiac death rate at 1 month and 1 year after emergency PCI in STEMI patients aged ≥75 years old.

Circ-HIPK2 Accelerates Cell Apoptosis and Autophagy in Myocardial Oxidative Injury by Sponging miR-485-5p and Targeting ATG101.

Myocardial injury has been deemed as a major cause of heart diseases including myocarditis and coronary heart disease, which have brought multiple mortalities globally. Long non-coding RNAs (lncRNAs) are widely recognized in diverse diseases. However, the role of circular RNA HIPK2 (circ-HIPK2) remains unclear in myocardial injury induced by H2O2. We attempted to investigate the probable role of circ-HIPK2 in myocardial injury induced by H2O2. This study discovered that the treatment of H2O2 inhibited cell proliferation but boosted cell apoptosis and autophagy. ATG101 was upregulated in primary mouse neonatal cardiomyocytes under H2O2 treatment. ATG101 knockdown promoted proliferation and limited apoptosis by attenuating autophagy in H2O2-injured mouse neonatal cardiomyocytes. Furthermore, miR-485-5p was validated to combine with ATG101 and circ-HIPK2, and circ-HIPK2 positively regulated ATG101 expression by sponging miR-485-5p. At last, silenced circ-HIPK2 mediated the promotion of cell proliferation, and repression of cell apoptosis was restored by ATG101 amplification. In a word, circ-HIPK2 facilitates autophagy to accelerate cell apoptosis and cell death in H2O2-caused myocardial oxidative injury through the miR-485-5p/ATG101 pathway, indicating a novel therapeutic target point for patients with myocardial injury.

Efficacy and safety of bivalirudin application during primary percutaneous coronary intervention in older patients with acute ST-segment elevation myocardial infarction.

OBJECTIVE: ST-segment elevation myocardial infarction (STEMI) is the most serious type of acute coronary syndrome. This study aimed to investigate the efficacy and safety of bivalirudin application during primary percutaneous coronary intervention (PPCI) in older patients with acute STEMI. METHODS: A total of 672 older patients with STEMI (>75 years) who underwent PPCI were studied. The primary endpoints were 30-day net adverse clinical events (NACEs) post-emergency percutaneous coronary intervention, including major adverse cardiac and cerebrovascular events (MACCEs) and Bleeding Academic Research Consortium grades 2 to 5 (BARC 2-5) bleeding events. RESULTS: The incidence of NACEs and BARC 2-5 bleeding events in the bivalirudin group was significantly lower than that in the unfractionated heparin group. Multivariate Cox regression analysis showed that bivalirudin significantly reduced 30-day NACEs (odds ratio: 0.700, 95% confidence interval: 0.492-0.995) and BARC 2-5 bleeding events (odds ratio: 0.561, 95% confidence interval: 0.343-0.918). At 1-year follow-up, these results were similar. CONCLUSIONS: Bivalirudin can be safely and effectively used during PPCI in older patients with STEMI. Bivalirudin reduces the risks of NACEs and bleeding within 30 days after PPCI, without increasing the risks of MACCEs and stent thrombosis compared with heparin.

Influence of CYP2C19 genotype on antiplatelet treatment outcomes after percutaneous coronary intervention in patients with coronary heart disease.

The aim of the study was to compare the clinical efficacy and safety of ticagrelor and clopidogrel in patients with coronary heart disease one year after percutaneous coronary intervention (PCI), and to explore their association with the CYP2C19 gene polymorphism. A total of 971 patients with coronary heart disease who were hospitalized and underwent PCI from April 2016 to May 2017 were studied. All 971 patients were divided into three subgroups according to CYP2C19 gene types as fast metabolizing, slow metabolizing and very slow metabolizing type. Patients were also classified according to the oral antiplatelet aggregation drugs they received: clopidogrel group and ticagrelor group. The incidence of major adverse cardiac events (MACE) and bleeding events in the clopidogrel-treated and ticagrelor-treated groups and in patients with fast, slow, and very slow CYP2C19 metabolisms were compared. Binary logistic regression analysis was carried out to analyze the risk factors associated with MACEs and hemorrhagic events. Patients on ticagrelor had a greater number of bleeding complications compared to those on clopidogrel (P<0.001), with no difference in MACE between the two groups (P=0.399). The incidence of MACE was significantly higher in very slow metabolizing patients receiving clopidogrel (P<0.001) while the incidence of bleeding complications was significantly higher in fast metabolizing patients receiving ticagrelor (P<0.001). The regression analysis revealed that the CYP2C19 gene mutation, a dual-antiplatelet therapy, and a stroke history were all significantly associated with MACE. By contrast, a dual-antiplatelet therapy and a stroke history were significantly associated with bleeding events. Findings of the present study indicated that clopidogrel and ticagrelor were equally efficacious post-PCI. Efficacy of clopidogrel was reduced in patients with very slow CYP2C19 genotype while bleeding complications were higher in patients with fast CYP2C19 genotype receiving ticagrelor. CYP2C19 genotyping may be used to provide guidance to optimize individual antiplatelet treatment.

Monitoring of the invasion of Spartina alterniflora from 1985 to 2015 in Zhejiang Province, China.

BACKGROUND: Spartina alterniflora is an invasive plant on the coast of China that replaces native vegetation and has a serious negative impact on local ecosystems. Monitoring the spatial distribution of S. alterniflora and its changes over time can reveal its expansion mechanism, which is crucial for the management of coastal ecosystems. The purpose of this study was to map the distribution of S. alterniflora in Zhejiang Province from 1985 to 2015 using a time series of Landsat TM/OLI images and analyze the temporal and spatial patterns of expansion of this species. RESULTS: After analyzing the distribution of coastal vegetation, the vegetation index was calculated based on Landsat images for 4 years (1985, 1995, 2005 and 2015). According to a threshold determined based on expert knowledge, the distribution of S. alterniflora in Zhejiang Province was extracted, and the temporal and spatial changes in the distribution of S. alterniflora were analyzed. The classification accuracy was 90.3%. S. alterniflora has expanded rapidly in recent decades after being introduced into southern Zhejiang. Between 1985 and 2015, S. alterniflora increased its area of distribution by 10,000 hm2, and it replaced native vegetation to become the most abundant halophyte in tidal flats. Overall, S. alterniflora expanded from south to north over the decades of the study, and the fastest expansion rate was 463.64 hm2/year, which occurred between 1995 and 2005. S. alterniflora was widely distributed in the tidal flats of bays and estuaries and expanded outward as sediment accumulated. CONCLUSIONS: This study reveals the changes over time in S. alterniflora cover in Zhejiang and can contribute to the control and management of this invasive plant.

High absorption shielding material of poly(phthalazinone etherketone)/multiwall carbon nanotube composite films with sandwich configurations.

Sandwich structure can be induced to achieve excellent electromagnetic interference shielding effectiveness (EMI SE) as is well known. However, how to optimize the structure to achieve performance optimization is still a problem. Herein, a poly(phthalazinone etherketone)/multiwall carbon nanotube (PPEK/MWCNT) composite with homodisperse and high content (15 wt%) of MWCNT was prepared by a water induced phase separation process. A sandwich structure was designed by introducing a wave-transmitting layer between the PPEK/MWCNT composite films. The MWCNT loading of the shielding layer and the wave-transmitting layer thickness (d) were varied to systematically investigate their influence on shielding performance in the X-band (8.2-12.4 GHz). EMI SE shows strong d value dependence. When the shielding layer was fixed, EMI SE showed a trend of decreasing, rising, leveling off and then decreasing again with d value increasing. The d value in the leveling off stage is the best value for performance optimization. The best d value decreased with increasing MWCNT content of the shielding layer. An absorption dominated SE up to 65 dB and a high increment rate of 140% of SE were achieved by optimization of the d value and shielding layer.