Structural heterogeneity of the ion and lipid channel TMEM16F.

Transmembrane protein 16 F (TMEM16F) is a Ca2+-activated homodimer which functions as an ion channel and a phospholipid scramblase. Despite the availability of several TMEM16F cryogenic electron microscopy (cryo-EM) structures, the mechanism of activation and substrate translocation remains controversial, possibly due to restrictions in the accessible protein conformational space. In this study, we use atomic force microscopy under physiological conditions to reveal a range of structurally and mechanically diverse TMEM16F assemblies, characterized by variable inter-subunit dimerization interfaces and protomer orientations, which have escaped prior cryo-EM studies. Furthermore, we find that Ca2+-induced activation is associated to stepwise changes in the pore region that affect the mechanical properties of transmembrane helices TM3, TM4 and TM6. Our direct observation of membrane remodelling in response to Ca2+ binding along with additional electrophysiological analysis, relate this structural multiplicity of TMEM16F to lipid and ion permeation processes. These results thus demonstrate how conformational heterogeneity of TMEM16F directly contributes to its diverse physiological functions.

Design and Fabrication of Annular-Array Ultrasound Transducer Based (K, Na) NbO3 Lead-Free 1-3 Piezoelectric Composite.

This article reports the design, fabrication, and performance of an annular-array ultrasound transducer using (K, Na)NbO3 (KNN)-based lead-free 1-3 piezoelectric composite. The 1-3 piezoelectric composite based on lead-free 0.965(K0.45Na0.55)(Nb0.96Sb0.04)O3-0.035 Bi0.5Na0.5Zr0.85Hf0.15O3 (KNNS-BNZH) was first prepared with the dice-and-fill method. Different from previous reported studies, by patterning annular electrodes on this kind of 1-3 composite, a five-element annular-array transducer in diameter of 6 mm was designed and successfully fabricated and its working center frequency was increased from 5 MHz to around 15 MHz. Meanwhile, a -6 dB bandwidth of 50% was achieved for each annular-array element via a pulse-echo response measurement. Moreover, the obtained annular-array transducer exhibits low crosstalk (<-40 dB) and a high electromechanical coupling coefficient of around 0.7. The application of ultrasonic imaging was further demonstrated to show its excellent performance. Both theoretical analysis and experimental results show that the obtained annular-array transducer presented in this work has a competitive capability for ultrasonic application.

Study on the Adsorption Behavior of Polymeric Dispersants to S-ZnF Particles during Grinding Process.

Three sodium polyacrylate copolymers PD0x (Poly acrylic acid-co-sodium 4-vinylbenzenesulfonate or PD01; Poly acrylic acid-co-sodium 4-vinylbenzenesulfonate-co-hydroxyethyl methacrylate or PD02 and Poly methyl methacrylate-co-acrylic acid-co-sodium 4-vinylbenzenesulfonate-co-hydroxyethyl methacrylate or PD03) were synthesized as water-based dispersants for grinding red-brown pigment ZnFe1.2Cr0.8O4 particles prepared by the solid phase method (S-ZnF). The particle size distribution, viscosity of suspensions, and adsorption capacity of dispersants were explored by laser particle size analysis, viscometer, and thermogravimetry (TG), respectively. The application of 2 wt.% dispersant PD02 in the S-ZnF suspension ground for 90 min can deliver a finer product with the narrower particle size distribution. The added dispersant PD02 in the grinding process of the S-ZnF particles exhibits a suitable viscosity of the suspension and generates more hydrogen bonds on the S-ZnF particle surface. The sulfonic acid groups (SO3-) and carboxylic acid groups (-COO-) in the dispersant PD02 can also provide a strong charge density, which is favorable for the dispersion and grinding of the S-ZnF particles in the suspensions. Furthermore, the adsorption behavior of polymeric dispersant PD02 adsorbed on the S-ZnF particles surface was simulated and analyzed by adsorption thermodynamic models and adsorption kinetic models. It is indicated that the adsorption thermodynamic behavior of dispersant PD02 adsorbed on the S-ZnF particles surface follows the Langmuir model, and the adsorption process is endothermic and a random process with increased confusion during the grinding process. In addition, the adsorption kinetics of dispersant PD02 adsorbed on the S-ZnF particles surface are more in line with the pseudo-first-order kinetic models. Therefore, the adsorption process of dispersant PD02 on the S-ZnF particles surface can be considered as a single-surface adsorption process.

Identification of serum miR-378 and miR-575 as diagnostic indicators and predicting surgical prognosis in human epilepsy.

Background: Epilepsy (EP) is a common neurological disorder which is characterized by excessive abnormal synchronization of neuronal discharges in the brain due to chronic recurrent seizures of multiple etiologies. Variety of microRNAs have been associated with the occurrence and development of EP. This study aimed to determine the aberrant expression of miR-378 and miR-575 in EP patients to validate their potential to distinguish EP from healthy patients. Methods: RT-qPCR was used to determine the expressions of miR-378 and miR-575 from serum specimens of 106 EP and 103 control individuals. Clinical indicators between EP patients and controls were assessed. Based on surgical outcome, EP patients were further divided into Engel I-IV EP. The potentials of miR-378 and miR-575 in discriminating EP from healthy participants and predicting surgical prognosis were calculated by receiver operating characteristic (ROC) analysis. Results: We found the miR-378 and miR-575 were significantly declined (P<0.001) in Engel I-II and III-IV EP patients with no difference in clinical parameters compared. Moreover, miR-378 and miR-575 displayed high sensitivity, specificity, and accuracy in distinguishing EP patients and predicting surgical outcomes. Moreover, after surgical treatment, miR-378 and miR-575 levels were increased compared with those at admission, suggesting their potentials in treatment response. Conclusions: miR-378 and miR-575 could be utilized as novel and non-invasive serum biomarkers in discriminating EP from healthy controls and predicting surgical outcome, shedding new insights on epileptogenesis and EP treatment.

Feasibility and risk assessment of heavy metals from low-temperature magnetic pyrolysis of municipal solid waste on a pilot scale.

Low-temperature magnetic pyrolysis (LMP) of municipal solid waste (MSW) was conducted in a pilot scale continuous reactor to investigate the distribution and transformation of heavy metals (HMs) in biochar. Environmental safety was evaluated by the risk assessment code (RAC) and the modified potential ecological risk index (MRI). Statistical analyses of HMs revealed that the total concentrations of HMs in biochar was higher than that in MSW and the exchangeable fraction of Cd in biochar under 200 °C and 250 °C were at high risk levels. Temperature increment indicates an increase in regular steps not only migrated more HMs into biochar, but also broke the immobilization of HMs, so resulted in higher environmental risks. The lowest direct toxicity to the environment was obtained by LMP at 200 °C. In light of the residual fraction and the high concentration of HMs in biochar produced in this work, it should be mixed with other uncontaminated plant waste for further application in agriculture. The results of economic assessment reveal that the value of net present value (NPV) and the internal rate of return (IRR) can be positive if high quality bio-products are produced with low operating costs. Optimized design of operation, feedstock and the investment are the key factors to improve the economic feasibility of LMP.

Automatic Quantification of Subsurface Defects by Analyzing Laser Ultrasonic Signals Using Convolutional Neural Networks and Wavelet Transform.

The conventional machine learning algorithm for analyzing ultrasonic signals to detect structural defects necessarily identifies and extracts either time- or frequency-domain features manually, which has problems in reliability and effectiveness. This work proposes a novel approach by combining convolutional neural networks (CNNs) and wavelet transform to analyze the laser-generated ultrasonic signals for detecting the width of subsurface defects accurately. The novelty of this work is to convert the laser ultrasonic signals into the scalograms (images) via wavelet transform, which are subsequently utilized as the image input for the pretrained CNN to extract the defect features automatically to quantify the width of defects, avoiding the necessity and inaccuracy induced by artificial feature selection. The experimentally validated numerical model that simulates the interaction of laser-generated ultrasonic waves with subsurface defects is first established, which is further utilized to generate adequate laser ultrasonic signals for training the CNN model. A total number of 3104 data are obtained from simulation and experiments, with 2480 simulated signals for training the CNN model and the remaining 620 simulated data together with 4 experimental signals for verifying the performance of the proposed algorithm. This approach achieves the prediction accuracy of 98.5% on validation set, particularly with the prediction accuracy of 100% for the four experimental data. This work proves the feasibility and reliability of the proposed method for quantifying the width of subsurface defects and can be further expanded as a universal approach to various other defects detection, such as defect locations and shapes.

Germacrone alleviates neurological deficits following traumatic brain injury by modulating neuroinflammation and oxidative stress.

BACKGROUND: Germacrone (GM) is a terpenoid compound which is reported to have anti-inflammatory and anti-oxidative effects. However, its role in treating traumatic brain injury (TBI) remains largely unknown. METHODS: Male C57BL/6 mice were divided into the following groups: control group, TBI group [controlled cortical impact (CCI) model], CCI + 5 mg/kg GM group, CCI + 10 mg/kg GM group and CCI + 20 mg/kg GM group. GM was administered via intraperitoneal injection. The neurological functions (including motor coordination, spatial learning and memory abilities) and brain edema were measured. Nissl staining was used to detect the neuronal apoptosis. Colorimetric assays and enzyme linked immunosorbent assay (ELISA) kits were used to determine the expression levels of oxidative stress markers including myeloperoxidase (MPO), malondialdehyde (MDA) and superoxide dismutase (SOD), as well as the expressions of inflammatory markers, including tumor necrosis factor α (TNF-α), interleukin-1ß (IL-1ß) and interleukin-6 (IL-6). Additionally, protein levels of Nrf2 and p-p65 were detected by Western blot assay. RESULTS: GM significantly ameliorated motor dysfunction, spatial learning and memory deficits of the mice induced by TBI and it also reduced neuronal apoptosis and microglial activation in a dose-dependent manner. Besides, GM treatment reduced neuroinflammation and oxidative stress compared to those in the CCI group in a dose-dependent manner. Furthermore, GM up-regulated the expression of antioxidant protein Nrf2 and inhibited the expression of inflammatory response protein p-p65. CONCLUSIONS: GM is a promising drug to improve the functional recovery after TBI via repressing neuroinflammation and oxidative stress.

Retraction: Metal-free [2+2+1] cycloaddition polymerization of alkynes, nitriles, and oxygen atoms to functional polyoxazoles.

[This retracts the article DOI: 10.1039/D0RA04249H.].

Correction: Metal-free [2+2+1] cycloaddition polymerization of alkynes, nitriles, and oxygen atoms to functional polyoxazoles.

[This corrects the article DOI: 10.1039/D0RA04249H.].

Effects of intravenous thrombolysis with alteplase combined with edaravone on cerebral hemodynamics and T lymphocyte level in patients with acute cerebral infarction.

Our study aimed to investigate the effect of intravenous thrombolysis with alteplase and edaravone on cerebral hemodynamics and T lymphocyte level in patients harboring acute cerebral infarction.There involved a total of 118 patients with acute cerebral infarction from November 2017 to May 2019 in our hospital were randomly divided into 2 groups: the observation group (59 patients were treated with intravenous thrombolysis with alteplase combined with edaravone) and the control group (59 patients were treated with intravenous thrombolysis of alteplase). The clinical effect, neurological function, cerebral hemodynamic index, T lymphocyte level, oxygen free radical scavenging level and oxidative stress index of the 2 groups were observed and compared.Before the treatment, there were no significant differences in neurological function, cerebral hemodynamic indexes, T-lymphocyte level, oxygen free radical scavenging level and oxidative stress indexes between the 2 groups (P > .05). After the treatment, the neurological function, cerebral hemodynamic indexes, T-lymphocyte level, oxygen free radical scavenging level and oxidative stress indexes of the 2 groups were significantly improved. In addition, the observation group exerted greater beneficial effect in terms of the clinical effect, neurologic function, cerebral hemodynamic index, T lymphocyte level, oxygen free radical scavenging level and oxidative stress index than those of the control group (P < .05).The intravenous thrombolysis with alteplase and edaravone is effective in the treatment of acute cerebral infarction, which also provides better results in terms of improving the clinical efficacy and prognosis of patients and might be an alternative option for clinical practice.

Effects of oxiracetam combined with ginkgo biloba extract in the treatment of acute intracerebral hemorrhage: A clinical study.

PURPOSE: The present clinical study was conducted to investigate the effect of oxiracetam combined with ginkgo biloba extract in treating patients with acute intracerebral hemorrhage. METHODS: Ninety-eight patients with acute cerebral hemorrhage admitted to our hospital were divided into three groups. The differences of brain edema and cerebral hemorrhage were compared between the three groups after 1 and 2 weeks of treatment, and the recovery of neurological function, serum inflammatory factors, AQP-4, MMP-9, cognitive function, activities of daily living, and adverse reactions were compared between the three groups after 2 weeks of treatment. RESULTS: There was no significant difference among the three groups before treatment (p > .05). After treatment, the recovery of neurological function, serum inflammatory factors, AQP-4, MMP-9 levels, cognitive function, and activities of daily living were improved. Among them, the neurological function recovery, serum inflammatory factors, AQP-4, MMP-9 levels, cognitive function, and activities of daily living in the combined treatment group and the control group elicited greater results than those in the routine group. The results of the combined treatment group showed the most significant difference (p < .05). The concentration of IL-6 decreased from 135.98 ± 12.54 to 91.83 ± 7.69 pg/ml, AQP-4 from 227.55 µg/L ± 21.06 to 114.31 ± 9.22 µg/L, and MMP-9 from 172.39 ± 9.81 to 94.98 ± 5.01 ng/ml. In addition, the neurological function recovery, the levels of serum inflammatory factors, cognitive function, and activities of daily living in the combined treatment group were better than those in the control group (p < .05). The mean score of MRS in the combined treatment group decreased from 3.36 ± 0.98 at admission to 1.91 ± 0.38. CONCLUSION: Oxiracetam combined with Ginkgo biloba extract in the treatment of acute cerebral hemorrhage has a significant improvement effect.

Retracted Article: Metal-free [2+2+1] cycloaddition polymerization of alkynes, nitriles, and oxygen atoms to functional polyoxazoles.

The metal-free [2+2+1] cycloaddition polymerization of alkynes, nitriles, and O-atoms for the regioselective assembly of highly substituted oxazole compounds has been achieved by the use of iodosobenzene (PhIO) with trifluoromethanesulfonic acid (TfOH). The present reaction could be applied to a facile synthesis of polyoxazoles. In this work, the cycloaddition polymerization of 4-cyano-4'-ethynylbiphenyl and PhIO was developed and modified polyoxazole was prepared. All experimental conditions such as polymerization solvent, temperature, catalyst and time were systematically studied. The structure of the obtained polyoxazole was characterized by GPC and NMR, and its thermal properties were studied by TGA. In addition, the good thermal stability of polyoxazoles with unreacted terminal alkynes and cyano groups makes them potentially useful for modifying resins.

Brush Swelling and Attachment Strength of Barnacle Adhesion Protein on Zwitterionic Polymer Films as a Function of Macromolecular Structure.

The exceptional hydration of sulfobetaine polymer brushes and their resistance toward nonspecific protein absorption allows for the construction of thin films with excellent antibiofouling properties. In this work, swollen sulfobetaine brushes, prepared by surface-initiated atom transfer radical polymerization of two monomers, differentiated by the nature of the polymerizable group, are studied and compared by a liquid-cell atomic force microscopy technique and spectroscopic ellipsometry. Colloidal AFM-based force spectroscopy is employed to estimate brush grafting density and characterize nanomechanical properties in salt water. When the ionic strength-induced swelling behaviors of the two systems are compared, the differences observed on the antipolyelectrolyte response can be correlated with the stiffness variation on brush compression, likely to be promoted by solvation differences. The higher solvation of amide groups is proposed to be responsible for the lower adhesion force of the barnacle cyprid's temporary adhesive proteins. The adhesion results provide further insights into the antibiofouling activity against barnacle cyprid settlement attributed to polysulfobetaine brushes.

New Insights into Planar Defects in Layered α-MoO3 Crystals.

The observation of regular ( h0 l) planar defects in α-MoO3 crystals can be traced back to over 60 years ago. Two mechanisms have been proposed to interpret the formation of the planar defects. One is related to the diffusion of oxygen vacancies because of thermal-driven release of oxygen atoms in vacuum and the consequent crystallographic shear of α-MoO3. The other is associated with redox reactions of moisture and/or hydrocarbons that give rise to H xMoO3 precipitates. Here, we report that regularly spaced (302) planar defects can be introduced into α-MoO3 belt crystals by heating in liquid sulfur at 300 °C. These defects are undetectable by both atomic force microscopy and scanning electron microscopy at the crystal surface. Raman scattering enhancement and weakening have been observed for different phonon modes of α-MoO3 at the (302) planar defects as probed from the (010) surface. Their comparisons with the Raman scattering enhancements at the edges and the argon-plasma-induced Raman spectral evolutions of the as-grown α-MoO3 belt crystals provide new insights into the planar defects with regard to their formation and characteristics.

Significant association of BDNF rs6265 G>A polymorphism with susceptibility to epilepsy: a meta-analysis.

INTRODUCTION: Previously published articles have suggested that BDNF rs6265 G>A polymorphism is a potential risk factor for epilepsy. However, the results were not consistent. METHODS: We conducted a meta-analysis to explore the association between BDNF rs6265 G>A polymorphism and epilepsy risk. Four online databases were searched, and related studies were reviewed from their inception up to June 20, 2017. ORs and corresponding 95% CIs were used to calculate the associations of each genetic model. Overall, 10 case-control publications involving 9,512 subjects were included in this meta-analysis. RESULTS: Significant associations were found between BDNF rs6265 G>A polymorphism and epilepsy (A vs G: OR=0.88, 95% CI=0.83-0.94, P<0.01, I2=0%; GA vs GG: OR=0.88, 95% CI=0.79-0.97, P=0.01, I2=0%; AA vs GG: OR=0.79, 95% CI=0.70-0.90, P<0.01, I2=0%; GA+AA vs GG: OR=0.85, 95% CI=0.77-0.94, P<0.01, I2=0%; AA vs GG+GA: OR=0.85, 95% CI=0.76-0.95, P=0.01, I2=0%). Subgroup analysis also showed similar results in an Asian population. CONCLUSION: Our meta-analysis indicated that BDNF rs6265 G>A polymorphism might be involved in epilepsy susceptibility, especially in the Asian population.

Plastic Strain Determination With Nonlinear Ultrasonic Waves Using In Situ Integrated Piezoelectric Ultrasonic Transducers.

The detection of plastic deformation of metallic alloy materials with second-harmonic Rayleigh ultrasonic wave is first investigated using direct-write piezoelectric ultrasonic transducers, in which piezoelectric poly(vinylidenefluoride/ trifluoroethylene) [P(VDF/TrFE)] polymer coatings and electrodes are directly deposited, processed, and patterned on the alloy to be evaluated. Rayleigh ultrasonic signals, generated by the direct-write transducers on titanium alloy specimens, are characterized by a laser scanning vibrometer. The results show that acoustic nonlinearity increases with plastic strain, and an increase of ~40% in the acoustic nonlinearity corresponding to a plastic strain of 5.1%. The measurement data and technical features with the use of the direct-write transducers are compared with the conventional discrete angle beam piezoelectric transducer. The results and analyses show that compared with the conventional discrete angle beam piezoelectric transducers, implementation of the direct-write piezoelectric transducers has significant technical advantages and is promising for applications in determining nonlinear ultrasonic waves and plastic strain of structural materials.

Stable pH responsive layer-by-layer assemblies of partially hydrolysed poly(2-ethyl-2-oxazoline) and poly(acrylic acid) for effective prevention of protein, cell and bacteria surface attachment.

Polyoxazolines have received increasing attention as low-fouling materials with good stability and ease of functional group incorporation. We investigated layer-by-layer (LbL) assembly of poly(2-ethyl-2-oxazoline) (PEOX) with poly(acrylic acid) (PAA) to incorporate PEOX into thin conformal coatings with controllable thicknesses ranging from the nano- to micron range. Partial hydrolysis of PEOX (to form PEOX-I) was used to introduce secondary amine groups that enable post-assembly multilayer stabilization by heat-induced crosslinking. While as-assembled multilayers dissolve in aqueous solutions at pH 5 and above, thermally crosslinked multilayers were stable against film loss and instead exhibit pH responsive swelling. The anti-fouling properties of crosslinked coatings were assessed by evaluating the resistance of PEOX-I containing multilayers to fouling by proteins, cells and bacteria. Our study of multilayers with thicknesses ranging from ∼12nm to ∼1.5µm revealed thickness dependence of surface fouling resistance to BSA. Crosslinked multilayers of ∼220nm were found to be highly effective in suppressing surface adsorption of bovine serum albumin (BSA), while thinner or thicker layers were increasingly susceptible to BSA adsorption. We further found that coatings of ∼220nm and above were all highly effective at preventing surface attachment of fibroblasts, gram-positive (S. aureus) and gram-negative (E. coli) bacteria.

Giant Blistering of Nanometer-Thick Al2O3/ZnO Films Grown by Atomic Layer Deposition: Mechanism and Potential Applications.

Giant circular blisters of up to 300 µm diameter and 10 µm deflection have been produced on nanometer-thick Al2O3-on-ZnO stacks grown by atomic layer deposition at 150 °C followed by annealing at elevated temperatures. Their shape changes upon varied ambient pressures provide evidence that their formation is related to an anneal-induced outgassing combined with their impermeability. The former mainly occurs in the bottom ZnO layer that recrystallizes and releases residual hydroxide ions at elevated temperatures while the latter is dominantly contributed by the pinhole-free Al2O3 layer on top. Vibrations at a resonant frequency of ∼740 kHz are mechanically actuated and optically probed from an individual blister. By modulating the thickness and stacking sequence of Al2O3 and ZnO, we further demonstrate a localized circular film swelling upon electron-beam irradiation and its recovery after reducing the irradiation flux. The elastic blistering and the recoverable swelling of the nanometer-thick films represent a miniaturized event-driven mechanical system for potential functioning applications.

Highly Efficient Supramolecular Aggregation-Induced Emission-Active Pseudorotaxane Luminogen for Functional Bioimaging.

The direct tracking of cells using fluorescent dyes is a constant challenge in cell therapy due to aggregation-induced quenching (ACQ) effect and biocompatibility issues. Here, we demonstrate the development of a biocompatible and highly efficient aggregation-induced emission (AIE)-active pseudorotaxane luminogen based on tetraphenylethene conjugated poly(ethylene glycol) (TPE-PEG2) (guest) and α-cyclodextrin (α-CD) (host). It is capable of showing significant fluorescent emission enhancement at the 400-600 nm range when excited at 388 nm, without increasing the concentration of AIE compound. The fluorescent intensity of TPE-PEG2 solution was effectively enhanced by 4-12 times with gradual addition of 1-4 mM of α-CD. 2D NOSEY 1H NMR revealed clear correlation spots between the characteristic peaks of α-CD and PEG, indicating the interaction between protons of ethylene glycol and cyclodextrin, and the structures are mainly based on threaded α-CD. The host-guest complex exhibits boosted fluorescent emission because the PEG side chains are confined in "nano-cavities" (host), thus, applying additional restriction on intermolecular rotation of TPE segments. In vitro cell experiments demonstrated the potential of AIE-active pseudorotaxane polymer as a biocompatible bioimaging probe.

Measuring protein isoelectric points by AFM-based force spectroscopy using trace amounts of sample.

Protein charge at various pH and isoelectric point (pI) values is important in understanding protein function. However, often only trace amounts of unknown proteins are available and pI measurements cannot be obtained using conventional methods. Here, we show a method based on the atomic force microscope (AFM) to determine pI using minute quantities of proteins. The protein of interest is immobilized on AFM colloidal probes and the adhesion force of the protein is measured against a positively and a negatively charged substrate made by layer-by-layer deposition of polyelectrolytes. From the AFM force-distance curves, pI values with an estimated accuracy of ±0.25 were obtained for bovine serum albumin, myoglobin, fibrinogen and ribonuclease A over a range of 4.7-9.8. Using this method, we show that the pI of the 'footprint' of the temporary adhesive proteins secreted by the barnacle cyprid larvae of Amphibalanus amphitrite is in the range 9.6-9.7.