Stabilized cobalt-free lithium-rich cathode materials with an artificial lithium fluoride coating

Iron-substituted cobalt-free lithium-rich manganese-based materials,with advantages of high specific capacity,high safety,and low cost,have been considered as the potential cathodes for lithium ion batteries.However,challenges,such as poor cycle stability and fast voltage fade during cycling under high potential,hinder these materials from commercialization.Here,we developed a method to directly coat LiF on the particle surface of Li_(1.2)Ni_(0.15)Fe_(0.1)Mn_(0.55O2).A uniform and flat film was successfully formed with a thickness about 3 nm,which can effect-ively protect the cathode material from irreversible phase transition during the deintercalation of Li^(+).After surface coating with 0.5wt%LiF,the cycling stability of Li_(1.2)Ni_(0.15)Fe_(0.1)Mn_(0.55O2) cycled at high potential was significantly improved and the voltage fade was largely suppressed.

Assisted Compatibility, and Balanced Regulation of the Mechanical, Thermal, and Antioxidant Activity of Polyvinyl Alcohol-Chinese Bayberry Tannin Extract Films Using Different Di-Aldehydes as Cross-Linkers

Polyvinyl alcohol(PVA)-based films containing Chinese bayberry tannin(BT)were prepared by cross-linking using glyoxal,glutaraldehyde and dialdehyde starch,individually.The presence of cross-linkers was evident to promote the transparency and decrease the moisture content of PVA/BT films,while the water solubility stayed almost unchanged in the cross-linked PVA/BTfilms.All cross-linkers provided promotion of the water vapor per-meability,mechanical property and thermal stability of PVA/BT films.The best water vapor barrier capacity was found in case of glutaraldehyde cross-linked PVA/BT film,while the highest tensile strength was encountered in case of glyoxal cross-linked PVA/BT films,compared with the uncross-linked films.The scavenging action of the films towards DPPH radical activity was influenced by the nature of each cross-linker.Namely,the PVA/AT film cross-linked by glutaraldehyde acquired the lowest radical scavenging activity in a certain time,suggesting that glutaraldehyde decreased the release rate of BT from PVA.Based on the experimental data,glutaraldehyde and dialdehyde starch could be more suitable for PVA/BT film preparation since they can promote the intermo-lecular interaction of PVA and BT to a reasonable extent.

Preparation of an Abrasive Grinding Wheel Based on Tannin Resin Cross- Linked by Furfuryl Alcohol, Urea and Glyoxal

Simple bio-based abrasive grinding wheel based on thermosetting resin matrix was developed starting with condensed tannin and furfuryl alcohol,which are mainly derived from forest and agricultural products like tree barks,wheat and crops.Fourier transform infrared spectra(FTIR)signified the acidic conditions are quiet efficient for the reaction of furfuryl alcohol,urea and glyoxal all together and the-CH_(2)-NH-and-CH_(2)-O-CH(OH)-groups are predominating in cross-linking of the tannin-furfuryl alcohol-urea-glyoxal(TFUG)resin.The strengthening contribution of the tannin was also confirmed by the preservation of its distinct crystallinity using X-ray diffraction(XRD).Differential scanning calorimetry(DSC)and thermogravimetric analysis(TGA)ensured that TFUG resin can be cured at low temperature and offer higher heat resistance compared with phenol-formaldehyde(PF)resin.The high hardness and excellent compressive strength revealed by the corresponding investigations such as Brinell hardness,compression resistance,and grinding tests suggested a strong abrasive ability using the new grinding wheel compared with lab-made grinding wheel based on PF resin.This could be ascribed to the absence of cracks and low content of formed holes as confirmed using scanning electron microscopy(SEM)and balanced reaction conditions that leads to network structure with regular local reinforcements and homogeneous crosslink density.

Sawtooth and dune auroras simultaneously driven by waves around the plasmapause

The dune aurora,at a scale of~30 kilometers,was reported recently using ground camera.The small-scale dune aurora occurs on the duskside and exhibits a monochromatic oscillation in the auroral emission,implying fundamental energy conversions.However,whether the dune auroras correspond to atmospheric waves or are associated with magnetospheric dynamics should be determined.This paper reports a dune aurora that occurred during a storm;further,we demonstrate that it was the substructure of the sawtooth aurora that was generated by plasmapause surface waves.Conjugate observations in the magnetospheric source region suggest that the exohiss waves,which are periodically modulated by the plasmapause surface wave-excited ultralow frequency wave,might be responsible for the generation of the dune aurora.Most reported dune aurora events have occurred simultaneously with sawtooth auroras,suggesting that both are plasmapause-driven cross-scale auroral structures.

Effect of Post-Added Water Amount on Pre-Concentrated Bark Foaming Materials by Mechanical Stirring

In this study,pre-concentrated bark,furfuryl alcohol and other biomass raw materials were used to prepare foaming materials by high-speed mechanical stirring without using a foaming agent.We investigated the effect of the postadded water amount on the properties of foaming materials.In particular,we determined basic physical properties of these materials,including the limiting oxygen index(LOI),porosity,thermal conductivity,thermogravimetric analysis,pore size distribution,and microstructure.The results of scanning electron microscopy(SEM)indicated that the pore size distribution was uniform and the pore size increased with increasing water volume.Thermogravimetric analysis(TG/DTG)showed that when the temperature reached 410°C,the foam was easily decomposed,the final residual mass was only 2.8%,and water addition had little effect on it.Moreover,the amount of post-added water is 5–30 g,the density and compression strength of the foamed materials gradually decreased,while the degree of pulverization increased.LOI ranged from 26.1%to 30.79%,and porosity ranged from 81%to 83%.The change in water volume greatly affected the foam’s performance,the performance of foamed material deteriorated as the amount of added water increased,but the effect on thermal conductivity was not very obvious.The highest thermal conductivity was only 0.0179 W/(m·K),still providing excellent thermal insulation.

Versatile bifunctional nitrogen-doped porous carbon derived from biomass in catalytic reduction of 4-nitrophenol and oxidation of styrene

The scarcity and weak durability of metal,especially precious metal catalysts are big obstacles for their large-scale application in many reactions.The state-of-the-art of the catalytic science prefers such type of catalysts,which can replace metal-based catalysts to alleviate energy and environmental crises and exhibit catalytic performance comparable to or even exceeding these metal catalysts.Herein,we report that N-doped porous carbon(NKC)derived from cheap and abundant radish can be employed as versatile and efficient bifunctional catalysts in both the catalytic reduction of 4-nitrophenol(NRR)and oxidation of styrene(SOR).The series of NKC catalysts were prepared with a simple and facile one-pot strategy by coupling the N-doping,carbonization and KOH activation processes.These catalysts show hierarchical porosity,with the specific surface area,total pore volume and N-doping content ranging from 918.9-3062.7 m^2 g^-1,1.01-2.04 cm^3 g^-1 and 1.29-15.3 at%,respectively.Interestingly,our finding suggests that the catalytic performance is not directly related to these parameters but correlates positively with the content of graphitic N dopants,which is the dominant contributor for impelling both the NRR and SOR.Another intriguing finding is that for both reactions,the optimal catalyst was found to be the NKC-3-800 which possesses the highest graphitic N content of 3.13 at%.In addition,to gain insight into the catalytic behavior,analyses of kinetics and thermodynamics were performed,and the catalytic mechanisms were postulated.This work paves the way for the construction of biomass-derived N-doped carbon catalysts for bi-or even multi-functional applications in various organic reactions.

Development of Antioxidant Packaging Film Based on Chinese Bayberry Tannin Extract and Polyvinyl Alcohol

The current work explores the potential use of commercial Chinese bayberry tannin(BT)to develop antioxidant PVA-based films using solvent casting process for packaging applications.The effect of BT concentration on opa-city,water resistance and antioxidant capacity of resulting films was investigated.Properties like tensile strength,thermal behavior,and morphological aspects were also characterized.The experimental results showed that PVA/BT films formed with uniformly brown color and generally good transparency,offering good antioxidant ability.The PVA film containing BT presented slightly higher water resistance according to the results of moisture content and water vapor permeability,especially at low BT content(<10 wt%).The PVA can be compounded with up to 10 wt%BT without any obvious deterioration in the tensile strength.The PVA/BT films exhibited better thermal degradation behavior compared with PVA alone because of the chemical bonds of PVA-BT and the for-mation of char at high temperature.Based on the results,PVA incorporated with Chinese bayberry tannin may provide broader formulation options for packaging materials with antioxidant action.

Tannin Resins for Wood Preservatives:A Review

Tannins and wood preservatives,in this article,are briefly introduced at beginning.The research and application progress on tannin resins for wood preservatives at home and abroad are reviewed.The significance and development prospects of research on tannins for wood preservatives are prospected.

Preparation and Characterization of Sandwich Structured Materials with Interesting Insulation and Fire Resistance

A cellular material in the form of 3-layered sandwich structure material was prepared via sole use of mechanical stirring without any use of a foaming agent,while Tween-80 was employed as a foam stabilizer via a developed in-situ mold casting.The resulting structure displayed a good appearance with no visual defects.The 3-layered composition of the sandwish structure,“nonporous resin layer-porous foam layer-nonporous resin layer”,was examined in terms of the microstructure,density&density distribution,pulverization ratio,mechanical strength,insulation and flame retardant performance.It was indicated from the results that the bonding between the resin layer and foam layer was tight,while the tensile rupture always occurred in the porous layer.Also,the density of the sandwich structure material was symmetrical with“saddle”distribution,and a uniform density for any given layer.The increase in the density at the interface layer provided a good interpretation for the tensile rupture never occurred at the interface.The brittleness resistance of the developed material was significantly improved,and the pulverization ratio was sharply decreased from 9.93%to 0.31%.The material acquired a thermal conductivity and limiting oxygen index(LOI)of 0.0241 W/m⋅K and 29.92%,respectively,indicating potential use of such materials broadly in fields of insulation and flame retardancy.

Extracellular signal regulated kinases 1/2 signal pathway and responses of astrocytes after diffuse brain injury

BACKGROUND： The treatment of diffuse brain injury during an acute period is focused on relieving degrees of secondary brain injury. Generation and development of pathological changes of secondary brain injury depend on signal conduction, so down-regulating over response of astrocyte through interfering a key link of signal conduction pathway may bring a new thinking for the treatment of diffuse brain injury. OBJECTIVE： To observe the effect of over activity of extracellular signal regulated kinases 1/2 （ERK1/2） signal pathway on the response of astrocyte during an acute period of diffuse brain injury. DESIGN： Completely randomized grouping and controlled animal study. SETTINGS： Department of Neurosurgery, the Third Affiliated Hospital, Nanchang University; Department of Neurosurgery, Union Hospital Affiliated to Tongji Medical College, Huazhong University of Science and Technology. MATERIALS： A total of 158 healthy male SD rats, of 11 weeks old, weighing 320-370 g, were provided by Experimental Animal Faulty, Tongji Medical College, Huazhong University of Science and Technology. Rabbit-anti-phosphorylated ERK1/2 （pERK1/2） polyclonal antibody was provided by R＆D Company; rabbit-anti-glial fibrillary acidic protein （GFAP） polyclonal antibody, SP immunohistochemical kit and horseradish peroxidase （HRP）-labeled goat-anti-rabbit IgG by Santa Cruz Company; specific inhibitor U0126 of ERK1/2 signal pathway by Alexis Company. METHODS： The experiment was carried out in the Laboratory of Neurosurgery, Union Hospital Affiliated to Tongji Medical College, Huazhong University of Science and Technology from September 2004 to March 2006. ① Detection of pERK1/2 expression： A total of 110 rats were randomly divided into sham operation group （n =5）, model group （n =35）, high-dosage U0126 group （n =35） and low-dosage U0126 group （n =35）. Rats in the sham operation group were only treated with incision of epicranium and fixation of backup plate, but not hit. Rats in the model group were used to establish diffuse brain injury models based on Marmarou free falling body without drug intervention. Rats in the high- and low-dosage U0126 groups were injected into caudal vein with 0.1 and 0.05 mg/kg U0126, respectively, and then, rats were hit to establish injured models. Every 5 rats were collected from model, high- and low-dosage U0126 groups at 5, 30 minutes, 3, 12, 24, 72 hours and 7 days after diffuse brain injury to detect pERK1/2 expression in cortex of parietal lobe based on Western blot technique. ② Distribution of pERK1/2 and positive GFAP cells in brain tissue： Another 48 rats were randomly divided into sham operation group （n =3）, model group （n =15）, high-dosage U0126 group （n =15） and low-dosage U0126 group （n =15）. The intervention and administration were dealt as the same as those mentioned above. Every 3 rats were collected from model, high- and low-dosage U0126 groups at 30 minutes, 3, 12, 24 and 72 hours after model establishment to observe the distribution of pERK1/2 and postive GFAP cells in brain tissue which was cut from coronal section at Bregma -4.8 mm layer with immunohistochemical staining. MAIN OUTCOME MEASURES： pERK1/2 expression in cortex of parietal lobe and distribution of pERK1/2 and positive GFAP cells in brain tissues. RESULTS： ① pERK1/2 expression： After diffuse brain injury, pERK1/2 expression in cortex of parietal lobe was rapidly increased in the model group, reached at peak at 5 minutes and then decreased gradually. But the expression was still in a high level until the 72nd hour and fallen to the basic level on the 7th day. pERK1/2 level was lower in high- and low-dosage U0126 groups than that in model group at various time points （P 〈 0.01）; meanwhile, pERK1/2 level was lower in high-dosage U0126 group than that in low-dosage U0126 group. The results showed that there was a certain dosage dependence on pERK1/2 expression. ② Distribution of pERK1/2 and positive GFAP cells in brain tissue： Positive expression of pERK1/2 lasted inbrain tissue from 30 minutes to 72 hours after diffuse brain injury （P 〈 0.05）. In addition, from 30 minutes to 3 hours, brown-yellow stained cells were mainly distributed in plasma, but rarely in nucleus. A lot of positive cells had tree-like apophysis, which was similar to neurons. With the time passing by, more and more nuclei manifested positive stains; moreover, nuclei mainly manifested positive staining until 24 hours after diffuse brain injury. Immune-positive pERK1/2 cells were widely distributed in brain tissue, especially mainly in binding site between deep cortex and cerebral white matter, and then in hippocampus. In addition, ependymal cell and vascular endothelial cells of choroids plexus also manifested strongly positive staining. As compared with model group, positive cells were decreased gradually in high- and low-dosage U0126 groups. However, number of positive cells was less in high-dosage U0126 group than that in low-dosage U0126 group. CONCLUSION： Diffuse brain injury strongly induces the activity of ERK1/2 signal pathway and response of astrocyte; in addition, U0126 can inhibit response of glial cells during an acute period, and the effect manifests dosage dependence.

Preparation of cobalt ferrite nanoparticles using fulvic acid as a capping agent and its effect on catalytic activity

Cobalt ferrite was prepared by co-precipitation from cobalt and iron soluble precursors in presence of fulvic acid at different pHvalues, namely, 6 and 8 and compared with the same preparation in absence of fulvic acid. The presence of fulvic acid is expected tobind metal ions through bridging before co-precipitation and mineralization. The extent of binding is determined according to thepH of the process. This influences the mineralization of the resulting cobalt ferrite and the crystallization/ordering of its lattice. Inaddition, the extent of residual ferric oxide is also a function of the efficiency of binding process. This route of modification for the coprecipitationprocess was found to be accompanied by enhanced surface area and total pore volume for most of the prepared samples.The involvement of these oxides as catalysts in the photo-catalytic degradation of phenol from wastewater was found to contributevery efficiently and the removal reached about 88% in some cases, which can be attributed to olation and oxolation process of theformed nanoparticles.

柔性界面分子智能感知

A series of captivating and intricate information exchanges occur on soft interfaces(such as cells interface,tissue surface or soft epidermis),whether among simple microorganisms like bacteria or in the most complex organisms like humans,such as ion diffusion across capillary membranes,neurotransmitter exchanges among synapses,and sweat secretion through sweat glands.Decoding these signals and emulating these interactions on biological interfaces will contribute to a better understanding of physiological processes and diseases,as well as the study of the humanmachine interface.One example is continuous real-time monitoring of physiological cues,like glucose levels in sweat,allowing for effective diabetes assessment and timely insulin therapy[1].

A survey on distributed compressed sensing： theory and applications

The compressed sensing （CS） theory makes sample rate relate to signal structure and content. CS samples and compresses the signal with far below Nyquist sampling frequency simultaneously. However, CS only considers the intra-signal correlations, without taking the correlations of the multi-signals into account. Distributed compressed sensing （DCS） is an extension of CS that takes advantage of both the inter- and intra-signal correlations, which is wildly used as a powerful method for the multi-signals sensing and compression in many fields. In this paper, the characteristics and related works of DCS are reviewed. The framework of DCS is introduced. As DCS＇s main portions, sparse representation, measurement matrix selection, and joint reconstruction are classified and summarized. The applications of DCS are also categorized and discussed. Finally, the conclusion remarks and the further research works are provided.

Retro-enantio isomer of angiopep-2 assists nanoprobes across the blood-brain barrier for targeted magnetic resonance/fluorescence imaging of glioblastoma

Glioblastoma(GBM),one of the most common primary intracranial malignant tumours,is very difficult to be completely excised by surgery due to its irregular shape.Here,we use an MRI/NIR fluorescence dual-modal imaging nanoprobe that includes superparamagnetic iron oxide nanoparticles(SPIONs)modified with indocyanine(Cy7)molecules and peptides(ANG orDANG)to locate malignant gliomas and guide accurate excision.Both peptides/Cy7-SPIONs probes displayed excellent tumour-homing properties and barrier penetrating abilities in vitro.

Advances in magnetic resonance imaging contrast agents for glioblastoma-targeting theranostics

Glioblastoma(GBM)is the most aggressive malignant brain tumour,with a median survival of 3 months without treatment and 15 months with treatment.Early GBM diagnosis can significantly improve patient survival due to early treatment and management procedures.Magnetic resonance imaging(MRI)using contrast agents is the preferred method for the preoperative detection of GBM tumours.However,commercially available clinical contrast agents do not accurately distinguish between GBM,surrounding normal tissue and other cancer types due to their limited ability to cross the blood-brain barrier,their low relaxivity and their potential toxicity.New GBM-specific contrast agents are urgently needed to overcome the limitations of current contrast agents.Recent advances in nanotechnology have produced alternative GBM-targeting contrast agents.The surfaces of nanoparticles(NPs)can be modified with multimodal contrast imaging agents and ligands that can specifically enhance the accumulation of NPs at GBM sites.Using advanced imaging technology,multimodal NP-based contrast agents have been used to obtain accurate GBM diagnoses in addition to an increased amount of clinical diagnostic information.NPs can also serve as drug delivery systems for GBM treatments.This review focuses on the research progress for GBMtargeting MRI contrast agents as well as MRI-guided GBM therapy.

The transcription factors TLR1 and TLR2 negatively regulate trichome density and artemisinin levels in Artemisia annua

The important antimalarial drug artemisinin is biosynthesized and stored in Artemisia annua glandular trichomes and the artemisinin content correlates with trichome density;however,the factors affecting trichome development are largely unknown.Here,we demonstrate that the A.annua R2R3 MYB transcription factor TrichomeLess Regulator 1(TLR1)negatively regulates trichome development.In A.annua,TLR1 overexpression lines had 44.7%–64.0%lower trichome density and 11.5%–49.4%lower artemisinin contents and TLR1-RNAi lines had 33%–93.3%higher trichome density and 32.2%–84.0%higher artemisinin contents compared with non-transgenic controls.TLR1 also negatively regulates the expression of anthocyanin biosynthetic pathway genes in A.annua.When heterologously expressed in Arabidopsis thaliana,TLR1 interacts with GLABROUS3a,positive regulator of trichome development,and represses trichome development.Yeast two-hybrid and pull-down assays indicated that TLR1 interacts with the WUSCHEL homeobox(WOX)protein AaWOX1,which interacts with the LEAFY-like transcription factor TLR2.TLR2 overexpression in Arabidopsis and A.annua showed that TLR2 reduces trichome development by reducing gibberellin levels.Furthermore,artemisinin contents were 19%–43%lower in TLR2-overexpressing A.annua plants compared to controls.These data indicate that TLR1 and TLR2 negatively regulate trichome density by lowering gibberellin levels and may enable approaches to enhance artemisinin yields.

Dual-band independent phase control based on high efficiency metasurface[Invited]

A general method to realize arbitrary dual-band independent phase control is proposed and demonstrated in this paper.A double-layered C-shape reflective meta-atom is designed to realize independent phase control with high efficiency.As a proof of concept,we propose two functional metasurfaces in the microwave region;the first metasurface performs beam steering in different directions,and the second metasurface generates achromatic beam steering at two distinct frequencies.Both simulation and measurement results agree well with the theoretical pre-setting.The maximum measured efficiency is 88.7%and 92.3%at 6.8 GHz and 8.0 GHz,respectively,for one metasurface,and 91.0%and 89.8%at 6.9 GHz and8.6 GHz,respectively,for the other.

Prediction of high infiltration levels in pituitary adenoma using MRI-based radiomics and machine learning

Background:Infiltration is important for the surgical planning and prognosis of pituitary adenomas.Differences in preoperative diagnosis have been noted.The aim of this article is to assess the accuracy of machine learning analysis of texture-derived parameters of pituitary adenoma obtained from preoperative MRI for the prediction of high infiltration.Methods:A total of 196 pituitary adenoma patients(training set:n=176;validation set:n=20)were enrolled in this retrospective study.In total,4120 quantitative imaging features were extracted from CE-T1 MR images.To select the most informative features,the least absolute shrinkage and selection operator(LASSO)and variance threshold method were performed.The linear support vector machine(SVM)was used to fit the predictive model based on infiltration features.Furthermore,the receiver operating characteristic curve(ROC)was generated,and the diagnostic performance of the model was evaluated by calculating the area under the curve(AUC),accuracy,precision,recall,and F1 value.Results:A variance threshold of 0.85 was used to exclude 16 features with small differences using the LASSO algorithm,and 19 optimal features were finally selected.The SVM models for predicting high infiltration yielded an AUC of 0.86(sensitivity:0.81,specificity 0.79)in the training set and 0.73(sensitivity:0.87,specificity:0.80)in the validation set.The four evaluation indicators of the predictive model achieved good diagnostic capabilities in the training set(accuracy:0.80,precision:0.82,recall:0.81,F1 score:0.81)and independent verification set(accuracy:0.85,precision:0.93,recall:0.87,F1 score:0.90).Conclusions:The radiomics model developed in this study demonstrates efficacy for the prediction of pituitary adenoma infiltration.This model could potentially aid neurosurgeons in the preoperative prediction of infiltration in PAs and contribute to the selection of ideal surgical strategies.

Elevated carbon dioxide stimulates nitrous oxide emission in agricultural soils: A global meta-analysis

Elevated carbon dioxide (CO_(2))(e CO_(2)) has been shown to affect the nitrous oxide (N_(2)O) emission from terrestrial ecosystems by altering the interaction of plants,soils,and microorganisms.However,the impact of e CO_(2) on the N_(2)O emission from agricultural soils remains poorly understood.This meta-analysis summarizes the effect of e CO_(2) on N_(2)O emission in agricultural ecosystems and soil physiochemical and biological characteristics using 50 publications selected.The e CO_(2) effect values,which equal to the percentage changes of N_(2)O emission under e CO_(2),were calculated based on the natural logarithm of the response ratio to e CO_(2).We found that e CO_(2) significantly increased N_(2)O emission (by 44%),which varied depending on experimental conditions,agricultural practices,and soil properties.In addition,e CO_(2) significantly increased soil water-filled pore space (by 6%),dissolved organic carbon content (by11%),and nitrate nitrogen content (by 13%),but significantly reduced soil p H (by 1%).Moreover,e CO_(2) significantly increased soil microbial biomass carbon(by 28%) and soil microbial biomass nitrogen (by 7%) contents.Additionally,e CO_(2) significantly increased the abundances of ammonia-oxidizing bacteria(AOB) amo A (by 21%),nir K (by 15%),and nir S (by 15%),but did not affect the abundances of ammonia-oxidizing archaea (AOA) amo A and nos Z.Our findings indicate that e CO_(2) substantially stimulates N_(2)O emission in agroecosystems and highlight that optimization of nitrogen management and agronomic options might suppress this stimulation and aid in reducing greenhouse effect.