Concentration-Dependent Effect of Nickel Ions on Amyloid Fibril Formation Kinetics of Hen Egg White Lysozyme:a Raman Spectroscopy Study

Nickel,an important transi-tion metal element,is one of the trace elements for hu-man body and has a crucial impact on life and health.Some evidences show the excess exposure to metal ions might be associated with neurological diseases.Herein,we applied Raman spectroscopy to study the Ni(II)ion effect on kinetics of amyloid fibrillation of hen egg white lysozyme(HEWL)in thermal and acidic conditions.Using the well-known Raman indicators for protein tertiary and secondary structures,we monitored and analyzed the concentration effect of Ni(II)ions on the unfolding of tertiary structures and the transformation of sec-ondary structures.The experimental evidence validates the accelerator role of the metal ion in the kinetics.Notably,the additional analysis of the amide I band profile,combined with thioflavin-T fluorescence assays,clearly indicates the inhibitory effect of Ni(II)ions on the formation of amyloid fibrils with organizedβ-sheets structures.Instead,a more significant promotion influence is affirmed on the assembly into other aggregates with disordered struc-tures.The present results provide rich information about the specific metal-mediated protein fibrillation.

Study on the Rural Tourism Development Strategy of Xuwen Pineapple Field under the Background of Rural Revitalization

With the overall promotion of the rural revitalization strategy,rural tourism has become an effective way to help rural revitalization.Xuwen pineapple field has a unique pineapple planting sightseeing belt in China,which is nicknamed the"sea of pineapple".It has high ornamental value and tourism attraction,and is very suitable for developing rural tourism.In this paper,Xuwen pineapple field is taken as research object.By literature research method and nominal cluster method,the factors influencing the development of rural tourism in Xuwen pineapple field are collected.Using 4P model analysis method and PEST model analysis method,the internal and external factors of rural tourism in Xuwen pineapple field are carefully combed.Finally,SWOT matrix analysis on the development of rural tourism in Xuwen pineapple field is carried out,and the development strategy of rural tourism in Xuwen pineapple field under the background of rural revitalization is obtained.

Gradient layered MXene/Fe_(3)O_(4)@CNTs/TOCNF ultrathin nanocomposite paper exhibiting effective electromagnetic shielding and multifunctionality

As wearable electronic devices are rapidly developing,there is an urgent need for lightweight,flexible,and ultrathin multifunctional electromagnetic interference(EMI)shielding materials.However,the flexible ultrathin paper that combines efficient shielding and multifunctional integration remains a considerable challenge.Here,a novel MXene/Fe_(3)O_(4)@CNTs/TOCNF(MCT,MXene=transition metal carbide/carbonitride,CNTs=carbon nanotubes,TOCNF=TEMPO-oxidized cellulose nanofiber,TEMPO=2,2,6,6-tetramethylpiperidine-1-oxyl radical)nanocomposite paper with a multilayer electromagnetic gradient structure and electromagnetic dual losses was successfully prepared by a simple filtration strategy.Benefiting from effective gradient design and adjusting the proportion of TOCNF,the composite paper(only 18μm)exhibits outstanding shielding effectiveness(SE)of 66 dB in the X-band,ultrahigh thickness-specific SE and surface-specific SE values of 3300 dB·mm-1 and 31,428 dB·cm^(2)·g^(-1)respectively.Furthermore,dehydroxylation treatment improves MCT paper's hydrophobicity,environmental stability,and mechanical strength,expanding its range of use.Excitingly,the highly efficient Joule heating properties and hydrophobicity provide MCT additional de-icing capabilities.We also simulated the electromagnetic shielding effects of MCT composite paper,which was applied in practice.This study documents an innovative and intriguing material combination,providing a simple and effective manufacturing strategy for developing EMI shielding materials.MCT paper is highly suitable for outdoor portable or wearable electronic devices and has significant application potential in humid/severe cold environments.

Side ionic-gated perovskite/graphene heterojunction synaptic transistor with bipolar photoresponse for neuromorphic computing

By combining the good charge transport property of graphene and the excellent photo-carrier generation char-acteristic of perovskite nanocrystal,we propose and demonstrate an ionic-gated synaptic transistor based on CsPbBr_(3)∕graphene heterojunction for bipolar photoresponse.Controlling the potential barrier of the CsPbBr_(3)∕graphene heterojunction by the ionic-gate of the electrical double-layer effect can promote the sepa-ration of photogenerated carriers and effectively retard their recombination.Using the ionic-gate-tunable Fermi level of graphene and the pinning effect of perovskite nanocrystal,the bipolar photocurrent responses correspond-ing to the excitatory and inhibitory short-term and long-term plasticity are realized by adjusting the negative gate bias.A series of synaptic functions including logic operation,Morse coding,the optical memory and electrical erasure effect,and light-assisted re-learning have also been demonstrated in an optoelectronic collaborative path-way.Furthermore,the excellent optical synaptic behaviors also contribute to the handwritten font recognition accuracy of-95%in artificial neural network simulations.The results pave the way for the fabrication of bipolar photoelectric synaptic transistors and bolster new directions in the development of future integrated human ret-inotopic vision neuromorphic systems.

Orientation and mobility control of 4HCB organic film for flexible X-ray detectors with high performance

In comparison to inorganic counterparts,organic semiconducting(OSC)crystalline films are promising for building large-area and flexible ionizing radiation detectors for X-ray imaging or dosimetry due to their tissue equivalence,simple processing and large-scale production accessibility.Fabrication processes,how-ever,hinder the ability to generate aligned and large-area films with high carrier mobility.In this work,the space-confined melt process is used to produce highly orientated 4HCB(4-hydroxycyanobenzene)OSC films with a large area of 15×18 mm^(2).The out-of-plane direction of the 4HCB film is<001>,and the benzene rings are found to be extensively overlapped inside the in-plane direction,according to the XRD patterns.The film exhibits a high resistivity up to 1012cm,and high hole mobility of 10.62 cm^(2)V^(−1)s^(−1).Furthermore,the 4HCB(80μm-thick film)based X-ray detectors can achieve a sensitivity of 93μC Gy air^(−1) cm^(−2)and on/offratio of 157.The device also shows steady flexibility,with no degradation in detecting function after 100 cycles of bending.Finally,the proposed 4HCB film detectors demonstrated a high-resolution X-ray imaging capability.The imaging of several materials with sharp edges(copper and polytetrafluoroethylene)has been obtained.This work has developed a fast but efficient approach for producing large-area,highly oriented OSC films for high-performance X-ray detectors.

Nontraditional oil sorbents:Hydrophilic sponges with hydrophobic skin layer for efficient oil spill remediation

Advances in the use of porous materials for oilwater separation offer a promising avenue for solving oil spill problems.Conventionally,to realize selective oil absorption,porous sorbents need to be fully hydrophobized with lowsurface-energy chemicals.However,such exhaustive hydrophobization brings about problems of excessive chemical consumption,high cost and increased environmental hazards,hindering the practical applications of sorbents.Here,an innovative type of oil sorbent is developed via a facile liquid film-based dip coating technique.Unlike conventional fullyhydrophobized sorbents,only the outmost layer of our sorbent is modified with hydrophobic polydimethylsiloxane(PDMS)coating while the inner part remains hydrophilic,thus achieving 80%reduction in low-surface-energy chemical consumption.The prepared sorbent allows highly selective oil absorption from oil-water mixture,as the hydrophobic skin layer blocks water entrance and the hydrophilic inner part drives oil absorption.More importantly,our sorbent significantly speeds up oil absorption,and compared with conventional hydrophobic sponges,the absorption time is reduced by 36%for absorption of the same mass of crude oil,attributed to the strong capillary absorption of its hydrophilic inner channels.This sorbent also shows larger specific absorption capacity than its fully hydrophobized counterpart.Our study provides a general strategy to develop cost-effective and environmental-benign sorbents with enhanced oil spill absorption performances.

Surface of room temperature ionic liquid [bmim][PF_6] studied by polarization- and experimental configuration-dependent sum frequency generation vibrational spectroscopy

Understanding and control of the surface properties such as molecular orientations are of great importance in numerous applications of ionic liquids. However, there remain discrepancies among the previous experimental and theoretical studies on the surface orientation and structures of room temperature ionic liquids(RTIL) systems. In this article, the orientation of 1-butyl-3-methylimidazolium([bmin]) cation at the air/liquid interface of a characteristic RTIL, 1-butyl-3-methylimidazolium hexafluorophosphate([bmim][PF6]), was investigated by the sum frequency generation vibrational spectroscopy(SFG-VS). Detailed polarization and experimental configuration analyses of the SFG-VS spectra showed the possibility of a small spectral splitting in the CH3 symmetric stretching region, which can be further attributed to the probable existence of multiple orientations for the interfacial [bmim] cations. In addition, the(N)–CH3 vibrations were absent, ruling out the prediction by several recent molecular dynamics simulations which state that portions of the [bmim] cations orient with a standing-up(N)–CH3 group at the ionic liquid surface. Hence, new realistic theoretical models have to be developed to reflect the complex nature of the ionic liquid surface.

Nanocellulose from bamboo shoots as perfect Pickering stabilizer:Effect of the emulsification process on the interfacial and emulsifying properties

In this work,the medium internal phase O/W Pickering emulsions stabilized with bamboo shoots nanocellulose(BSNC)was successfully fabricated.The nanocellulose extracted from bamboo shoots with an average width of 56.37 nm and height of 7.44 nm showed great potential as an emulsifier in the Pickering emulsions.The effects of BSNC content,oil-water ratio and emulsification process on the structure,stability and rheology of the resultant Pickering emulsions was explored.The obtained emulsion with the BSNC content of 0.5 wt%at the oil to water volume ratio of 5:5 had a lower particle size of around 25μm.With the increasing BSNC content,the emulsions presented increased droplet size,and even demulsification occurred.Interestingly,the physicochemical properties of the emulsions could be significantly improved through twice shearing,which effectively reduced droplet size.The surface coverage was above 100%for the Pickering emulsions stabilized with the BSNC content of 0.5%-1.1%.With the increasing BSNC content,the apparent viscosity was increased first and then decreased,and all emulsions showed elastic behaviors.This work would provide theoretical guidance for preparing medium or high internal phase Pickering emulsions stabilized with nanocellulose.