Bovine serum albumin:An efficient and green biocatalyst for the one-pot four-component synthesis of pyrano[2,3-c]pyrazoles

The use of biocatalysts is attracting an increasing amount of attention in chemical catalysis.Here,we have shown that bovine serum albumin（BSA）,a ubiquitous,inexpensive,non-enzymatic transport protein,can serve as an efficient,retrievable catalyst in the one-pot four-component reaction of aryl aldehydes,malononitrile,hydrazine hydrate,and ethyl acetoacetate for the synthesis of pyrano[2,3-c]pyrazoles under mild reaction conditions.The BSA biocatalyst also displayed a high catalytic affinity for acyclic/cyclic ketones to yield the corresponding pyrano[2,3-c]pyrazoles or their spirocyclic variants.The BSA could be used for at least five cycles without serious loss of catalytic activity.This novel,efficient protocol has the merits of high yield,operational simplicity,and a relatively benign environmental impact.Moreover,the method extends the promiscuity of BSA as a biocatalyst.

Motor network reorganization in stroke patients with dyskinesias during a shoulder-touching task:A fNIRS study

Hemiplegia after stroke has become a major cause of the world's high disabilities,and it is vital to enhance our understanding of post-stroke neuroplasticity to develop e±cient rehabilitation programs.This study aimed to explore the brain activation and network reorganization of the motor cortex(MC)with functional near-infrared spectroscopy(fNIRS).The MC hemodynamic signals were gained from 22 stroke patients and 14 healthy subjects during a shoulder-touching task with the right hand.The MC activation pattern and network attributes analyzed with the graph theory were compared between the two groups.The results revealed that healthy controls presented dominant activation in the left MC while stroke patients exhibited dominant activation in the bilateral hemispheres MC.The MC networks for the two groups had small-world properties.Compared with healthy controls,patients had higher transitivity and lower global e±ciency(GE),mean connectivity,and long connections(LCs)in the left MC.In addition,both MC activation and network attributes were correlated with patient's upper limb motor function.The results showed the stronger compensation of the unaffected motor area,the better recovery of the upper limb motor function for patients.Moreover,the MC network possessed high clustering and relatively sparse inter-regional connections during recovery for patients.Our results promote the understanding of MC reorganization during recovery and indicate that MC activation and network could provide clinical assessment signi¯cance in stroke patients.Given the advantages of fNIRS,it shows great application potential in the assessment and rehabilitation of motor function after stroke.

Ferroptosis molecular inducers:A future direction for malignant tumor chemotherapy

Iron-dependent ferroptosis is a form of cell death dependent on iron levels.Cells that undergo ferroptosis have glutathione(GSH)deficiency,reduced Glutathione peroxidase-4(GPX4)activity and intracellular lipid peroxidation,Mitochondria,lysosomes and many signal pathways are involved in the regulation of ferroptosis.More importantly,many tumor cells resistant to other cell death methods exhibit sensitivity to ferroptosis.Moreover,over recent years,a number of ferroptosis-induced drugs have been recommended for the treatment of malignant tumors.Therefore,the study of ferroptosis is of great significance for future cancer treatments.In this review,we discussed the metabolic process of ferroptosis,the role of different organelles,the typical signaling pathways involved in ferroptosis,as well as natural and synthetic compounds that can induce ferroptosis,aiming to point out new conceptual avenues for utilizing ferroptosis in future cancer treatments.

Glucocorticoid reduces the efficacy of afatinib on the head and neck squamous cell carcinoma

Glucocorticoids(GC)are widely used to counter the adverse events during cancer therapy;nonetheless,previous studies pointed out that GC may reduce the efficacy of chemotherapy on cancer cells,especially in epidermal growth factor receptor(EGFR)-targeted therapy of head and neck squamous cell carcinoma(HNSCC)remaining to be elucidated.The primary aim of the present study was to probe into the GC-induced resistance of EGFR-targeted drug afatinib and the underlying mechanism.HNSCC cell lines(HSC-3,SCC-25,SCC-9,and H-400)and the human oral keratinocyte(HOK)cell lines were assessed for GC receptor(GR)expression.The promoting tumor growth effect of GC was evaluated by the CCK-8 assay and flow cytometry.Levels of signaling pathways participants GR,mTOR,and EGFR were determined by quantitative polymerase chain reaction and western blotting.GC increased the proliferation of HNSCC cells in a GR-dependent manner and promoted AKT/mTOR signaling.But GC failed in counteracting the inhibition of rapamycin in the mTOR signaling pathway.Besides,GC also induced resistance to EGFR-targeted drug afatinib through AKT/mTOR instead of the EGFR/ERK signaling pathway.Thus,GCs reduce the efficacy of afatinib on HNSCC,implicating a cautious use of glucocorticoids in clinical practice.

Anisotropic thermoelectric transport properties in polycrystalline SnSe_(2)

It is reported that SnSe_(2) consisting of the same elements as SnSe, is a new promising thermoelectric material with advantageous layered structure. In this work, the thermoelectric performance of polycrystalline SnSe_(2) is improved through introducing SnSe phase and electron doping(Cl doped in Se sites). The anisotropic transport properties of SnSe_(2) are investigated. A great reduction of the thermal conductivity is achieved in SnSe_(2) through introducing SnSe phase, which mainly results from the strong SnSe_(2)–SnSe inter-phase scattering. Then the carrier concentration is optimized via Cl doping, leading to a great enhancement of the electrical transport properties, thus an extraordinary power factor of ^5.12 μW·cm^(-1)·K^(-2) is achieved along the direction parallel to the spark plasma sintering(SPS) pressure direction( P). Through the comprehensive consideration on the anisotropic thermoelectric transport properties, an enhanced figure of merit ZT is attained and reaches to ^ 0.6 at 773 K in SnSe_(2)-2% SnSe after 5% Cl doping along the P direction, which is much higher than ^ 0.13 and ^ 0.09 obtained in SnSe_(2)-2% SnSe and pristine SnSe_(2) samples, respectively.

Correlation between knowledge of prevention COVID-19 and depression of residents in Henan province,China

Background:Coronavirus disease 2019(COVID-19) has shown explosive growth in cities in central China in recent days.Residents have the depression due to lack of corresponding prevention knowledge.Methods:A cross-sectional study was investigated 385 residents over 18 years of age.Structured questionnaire and DASS-21 scale used to explore the association between knowledge of prevention COVID-19 and depression among residents.Results:73 respondents (20.3%) suffered varying degrees of depression.The knowledge of the behavior of respondents most concerned (AOR 7.45,95%CI,1.87 ~ 29.77),the main symptoms of the COVID-19 (AOR 9.72,95%CI,1.19 ~ 79.12) and using special ambulances to transport patients or suspected patients (AOR 2.22,95%CI,1.07 ~ 4.62) was found to be significant related to depression.Conclusions:Although residents currently have a lower prevalence of depression,but there is a strong correlation between the knowledge and attitude of prevention COVID-19 and depression.Government agencies need to expand ways to spread the knowledge of prevention COVID-19.

FKF1b controls reproductive transition associated with adaptation to geographical distribution in maize

Maize(Zea mays subspecies mays)is an important commercial crop across the world,and its flowering time is closely related to grain yield,plant cycle and latitude adaptation.FKF1 is an essential clock-regulated blue-light receptor with distinct functions on flowering time in plants,and its function in maize remains unclear.In this study,we identified two FKF1 homologs in the maize genome,named ZmFKF1a and ZmFKF1b,and indicated that ZmFKF1a and ZmFKF1b independently regulate reproductive transition through interacting with ZmCONZ1 and ZmGI1 to increase the transcription levels of ZmCONZ1 and ZCN8.We demonstrated that ZmFKF1b underwent artificial selection during modern breeding in China probably due to its role in geographical adaptation.Furthermore,our data suggested that ZmFKF1bHap_C7 may be an elite allele,which increases the abundance of ZmCONZ1 mRNA more efficiently and adapt to a wider range of temperature zone than that of ZmFKF1bHap_Z58 to promote maize floral transition.It extends our understanding of the genetic diversity of maize flowering.This allele is expected to be introduced into tropical maize germplasm to enrich breeding resources and may improve the adaptability of maize at different climate zones,especially at temperate region.

Four-coordinate disilyl cobalt(Ⅱ)complexes with NHC ligation:Synthesis,characterization,and reactivity

Silyl cobalt species are putative intermediates in cobalt-catalyzed transformations of hydrosilanes.However,their reactivity has remained poorly understood.Reported here is the investigation on four-coordinate disilyl Co(Ⅱ)complexes with N-hetereocyclic carbene ligation.The reactions of[(ICy)_(2)Co(vtms)](ICy=1,3-dicyclohexylimidazol-2-ylidene,vtms=vinyltrimethylsilane)with primary and secondary hydrosilanes(3 equiv.)furnish the four-coordinate disilyl complexes[trans-(ICy)_(2)Co(SiHRR')_(2)](SiHRR'=SiH_(2)Mes,1;SiH_(2)Ph,2;SiH_(2)Cy,3;SiHPh_(2),4;SiHEt_(2),5)in moderate to good yields.The structures of 1,2 and 4 were established by single-crystal X-ray diffraction.Solution magnetic susceptibility measurement and EPR spectroscopy indicate their low-spin nature(S=1/2).Reactivity studies on 4 led to the establishment of the conversions of 4 to the disilyl dihydride Co(Ⅲ)complex[K(THF)][(ICy)_(2)Co(H)_(2)(SiHPh_(2))_(2)]_n(6)and the fluorosilyl Co(Ⅱ)complex[(ICy)_(2)Co(THF)(SiFPh_(2))][BF_(4)](7)when 4 was treated with excess amount of K and AgBF_(4),respectively,in THF.These conversions hint at the high activity of low-valent and high-valent disilyl cobalt species[trans-(ICy)_(2)Co(SiHPh_(2))_(2)]^(1-)and[trans-(ICy)_(2)Co(SiHPh_(2))_(2)]^(2+).Complex 4 is reactive toward terminal alkynes,but inert toward alkenes and internal alkynes.The reactions of 4 with terminal alkynes CyC≡CH and Me_(3)SiC≡CH(3 equiv.)yield the Co(Ⅱ)complexes[(ICy)_(2)Co(C≡CCy)_(2)](8)and[(ICy)_(2)Co(C≡CSiMe_(3))((SiMe_(3))C=CH_(2))](9),respectively,along with H_(2)SiPh_(2)and alkynylsilanes RC≡CSiHPh_(2)(R=Cy,SiMe_(3)),whereas the reaction with 4-CF_(3)C_(6)H_(4)C≡CH(3 equiv.)produce[(ICy)_(2)Co(C≡CAr)((Ar)C=CH(SiHPh_(2))C=CHAr)](Ar=4-CF_(3)C_(6)H_(4))(10)and H_(2)SiPh_(2).These reactions are proposed to involveσ-bond metathesis reactions between alkyne C(sp)-H bonds and Co-Si bonds in 4.Complexes 6–10 have been characterized by NMR spectroscopy,X-ray diffraction study,and elemental analysis.

Asymmetric frequency multiplexing topological devices based on a floating edge band

Topological photonics provides a platform for robust energy transport regardless of sharp corners and defects.Recently,the frequency multiplexing topological devices have attracted much attention due to the ability to separate optical signals by wavelength and hence the potential application in optical communication systems.Existing frequency multiplexing topological devices are generally based on the slow light effect.However,the resulting static local spatial mode or finely tuned flat band has zero-group velocity,making it difficult for both experimental excitation and channel out-coupling.Here,we propose and experimentally demonstrate an alternative prototype of asymmetric frequency multiplexing devices including a topological rainbow and frequency router based on floating topological edge mode(instead of localized ones);hence the multiple wavelength channels can be collectively excited with a point source and efficiently routed to separate output ports.The channel separation in our design is achieved by gradually tuning the band gap truncation on a topological edge band over a wide range of frequencies.A crucial feature lies in that the topological edge band is detached from bulk states and floating within the upper and lower photonic band gaps.More interestingly,due to the sandwiched morphology of the edge band,the top and bottom band gaps will each truncate into transport channels that support topological propagation towards opposite directions,and the asymmetrical transportation is realized for the frequency multiplexing topological devices.

Electromagnetic anisotropic homogeneous model for eddy-current field in single-phase wound core

The analysis of the eddy-current field in the wound core widely used in the field of transformer energy conservation is taken as the theme.Adopting the homogenisation idea to consider the unique geometry of the wound core and features of its equivalent multi-stage circular cross-section magnetic boundary,a homogeneous model consisting of a columnar material with continuous homogeneous electromagnetic anisotropy is established by deriving the Maxwell equations of the magnetic quasi-static field in the columnar coordinate system.Finally,a homogeneous fine element model for the eddycurrent field in the wound core is established and the accuracy of the model has been verified by the test platform.The result shows that the homogeneous model can be effectively used for the analysis of the eddy-current field in the wound core,and the error of calculating the eddy-current loss under different excitation conditions is less than 6%under the premise of extremely saving the engineering calculation cost,which will help improve the operational performance of the wound core and contribute to the energysaving goal of the high-voltage equipment.

Extremely low thermal conductivity from bismuth selenohalides with 1D soft crystal structure

Materials with intrinsically low thermal conductivity are of fundamental interests.Here we report a new sort of simple one-dimensional(1 D)crystal structured bismuth selenohalides(Bi Se X,X=Br,I)with extremely low thermal conductivity of^0.27 W m^-1K^-1 at 573 K.The mechanism of the extremely low thermal conductivity in 1 D Bi Se X is elucidated systematically using the first-principles calculations,neutron powder-diffraction measurements and temperature tunable aberration-corrected scanning transmission electron microscopy(STEM).Results reveal that the1 D structure of Bi Se X possesses unique soft bonding character,low phonon velocity,strong anharmonicity of both acoustic and optical phonon modes,and large off-center displacement of Bi and halogen atoms.Cooperatively,all these features contribute to the minimal phonon transport.These findings provide a novel selection rule to search low thermal conductivity materials with potential applications in thermoelectrics and thermal barrier coatings.

Surface-ligand protected reduction on plasmonic tuning of one-dimensional MoO_(3−x)nanobelts for solar steam generation

Sub-stoichiometric MoO_(3−x)nanostructures with plasmonic absorption via creating oxygen vacancies have attracted extensive attentions for many intriguing applications.However,the synthesis of one-dimensional(1D)plasmonic MoO_(3−x)nanostructures with widely tunable plasmonic absorption has remained a significant challenge because of their serious morphological destruction and phase change with increasing the concentration of oxygen vacancies.Here we demonstrate a surface-ligand protected reduction strategy for the synthesis of 1D MoO_(3−x)nanobelts with tunable plasmonic absorption in a wide wavelength range from 200 to 2,500 nm.Polyethylene glycol(PEG-400)is used as both the reductant to produce oxygen vacancies and the surface protected ligands to maintain 1D morphology during the formation process of MoO_(3−x)nanobelts,enabling the widely tunable plasmonic absorption.Owing to their broad plasmonic absorption and unique 1D nanostructure,we further demonstrate the application of 1D MoO_(3−x)nanobelts as photothermal film for interfacial solar evaporator.The surface-ligand protected reduction strategy provides a new avenue for the developing plasmonic semiconductor oxides with maintained particle morphology and thus enriching their wide applications.

Low carrier concentration leads to high in-plane thermoelectric performance in n-type SnS crystals

As a simple binary compound, p-type SnS shows great competitiveness in thermoelectrics due to the certain appealing carrier and phonon transport behaviors, coupled with its cost-effectiveness, earth-abundance and environmental compatibility. To promote the application of low-cost thermoelectric devices, we synthesized n-type SnS crystals through bromine doping. Herein, we report a high in-plane power factor of ~28 μW cm^(-1)K^(-2), and attribute it to an outstanding in-plane carrier mobility in the crystal form and the large Seebeck coefficient benefitting from the low carrier concentration. The calculations of elastic properties show that the low lattice thermal conductivity in SnS is closely related to its strong anharmonicity. Combining the excellent electrical transport properties with low thermal conductivity, a final ZT of ~0.4 is attained at 300 K, projecting a conversion efficiency of ~5% at 873 K along the in-plane direction.

Slowing down the heat in thermoelectrics

Heat transport has various applications in solid materials.In particular,the thermoelectric technology provides an alternative approach to traditional methods for waste heat recovery and solid-state refrigeration by enabling direct and reversible conversion between heat and electricity.For enhancing the thermoelectric performance of the materials,attempts must be made to slow down the heat transport by minimizing their thermal conductivity(κ).In this study,a continuously developing heat transport model is reviewed first.Theoretical models for predicting the lattice thermal conductivity(κlat)of materials are summarized,which are significant for the rapid screening of thermoelectric materials with lowκlat.Moreover,typical strategies,including the introduction of extrinsic phonon scattering centers with multidimensions and internal physical mechanisms of materials with intrinsically lowκlat,for slowing down the heat transport are outlined.Extrinsic defect centers with multidimensions substantially scatter various-frequency phonons;the intrinsically lowκlat in materials with various crystal structures can be attributed to the strong anharmonicity resulting from weak chemical bonding,resonant bonding,low-lying optical modes,liquid-like sublattices,off-center atoms,and complex crystal structures.This review provides an overall understanding of heat transport in thermoelectric materials and proposes effective approaches for slowing down the heat transport to depressκlat for the enhancement of thermoelectric performance.

Realizing ranged performance in SnTe through integrating bands convergence and DOS distortion

As a typical IV-VI compound,SnTe has aroused widely attentions in the thermoelectric community due its similar crystal and band structures with PbTe.However,both the large number of inherent Sn vacancies and high thermal conductivity result in inferior thermoelectric performance in intrinsic SnTe over a broad temperature.In this work,we successfully improved those disadvantages of SnTe via stepwisely Pb heavily alloying and then In doping.A significantly wide fraction of Pb into SnTe(0-50%)achieves multiple effects:(a)the carrier concentration of SnTe is reduced through decreasing Sn vacancies via alloying high solution Pb atoms in the matrix;(b)the band structure is optimized through promoting the convergence of the two valence bands,simultaneously enhancing the Seebeck coefficient;(c)HAADF-STEM coupled with EDS results illustrate that guest Pb atoms randomly and uniformly occupied Sn atomic sites in the matrix,concurrently strengthening the phonon scattering.Furthermore,we introduced indium into Sn_(0.6)Pb_(0.4)Te system to create resonant states further enlarging the power factors at low-medium temperature.The integration of bands convergence and DOS distortion achieves a considerably high ZT_(ave) of~0.67 over the wide temperature range of 300-823 K in(Sn_(0.6)Pb_(0.4))_(0.995)In_(0.005)Te sample.

Topology-empowered membrane devices for terahertz photonics

Control of terahertz waves offers a profound platform for next-generation sensing,imaging,and information communications.However,all conventional terahertz components and systems suffer from bulky design,sensitivity to imperfections,and transmission loss.We propose and experimentally demonstrate onchip integration and miniaturization of topological devices,which may address many existing drawbacks of the terahertz technology.We design and fabricate topological devices based on valley-Hall photonic structures that can be employed for various integrated components of on-chip terahertz systems.We demonstrate valleylocked asymmetric energy flow and mode conversion with topological waveguide,multiport couplers,wave division,and whispering gallery mode resonators.Our devices are based on topological membrane metasurfaces,which are of great importance for developing on-chip photonics and bring many features into terahertz technology.

Hydrogel electrodes with conductive and substrate-adhesive layers for noninvasive long-term EEG acquisition

Noninvasive brain–computer interfaces (BCIs) show great potential in applications including sleep monitoring, fatigue alerts, neurofeedback training, etc. While noninvasive BCIs do not impose any procedural risk to users (as opposed to invasive BCIs), the acquisition of high-quality electroencephalograms (EEGs) in the long term has been challenging due to the limitations of current electrodes. Herein, we developed a semidry double-layer hydrogel electrode that not only records EEG signals at a resolution comparable to that of wet electrodes but is also able to withstand up to 12 h of continuous EEG acquisition. The electrode comprises dual hydrogel layers: a conductive layer that features high conductivity, low skin-contact impedance, and high robustness;and an adhesive layer that can bond to glass or plastic substrates to reduce motion artifacts in wearing conditions. Water retention in the hydrogel is stable, and the measured skin-contact impedance of the hydrogel electrode is comparable to that of wet electrodes (conductive paste) and drastically lower than that of dry electrodes (metal pin). Cytotoxicity and skin irritation tests show that the hydrogel electrode has excellent biocompatibility. Finally, the developed hydrogel electrode was evaluated in both N170 and P300 event-related potential (ERP) tests on human volunteers. The hydrogel electrode captured the expected ERP waveforms in both the N170 and P300 tests, showing similarities in the waveforms generated by wet electrodes. In contrast, dry electrodes fail to detect the triggered potential due to low signal quality. In addition, our hydrogel electrode can acquire EEG for up to 12 h and is ready for recycled use (7-day tests). Altogether, the results suggest that our semidry double-layer hydrogel electrodes are able to detect ERPs in the long term in an easy-to-use fashion, potentially opening up numerous applications in real-life scenarios for noninvasive BCI.

Experimental study on ageing characteristics of electric locomotive ethylene propylene rubber cable under mechanical-thermal combined action

The train-mounted ethylene propylene rubber(EPR)cables of electric locomotive are partly restricted by the body structure and spatial layout and are in a combined envi-ronment of strong mechanical bending and thermal ageing.The degradation character-istics of the insulation layer have not yet received sufficient attention.In order to study the ageing characteristics of EPR cables of electric locomotive under the combined action of machine and thermal,this paper designs a bending-thermal combined ageing test platform for cables with a temperature of 135°C,bending diameter of 393.52 mm,590.28 mm and unbending cables,and tests after ageing.The product has been tested by infrared spectroscopy,scanning electron microscopy,elongation at break and broadband dielectric spectroscopy.The research results show that the bending outer part of the train-mounted EPR cable is a pain point.Under the combined action of bending and thermal,whether it is microstructure or macro performance,the degradation rate and degree of the bending of outer insulation layer are greater than the value under a single thermal ageing condition.Mechanical bending has an accelerating effect on the ageing of the EPR insulation layer.The research results can provide a reference for the ageing characteristics of the train-mounted EPR cable under the bending-thermal synergy and the evaluation of operating state of the train-mounted EPR cable under bending-thermal operating conditions.

A promising thermoelectrics In_(4)SnSe_(4) with a wide bandgap and cubic structure composited by layered SnSe and In_(4)Se_(3)

The wide-bandgap cubic-structure semiconductor In_(4)SnSe_(4) can be regarded as a product of compositing two typical layered thermoelectric materials SnSe and In_(4)Se_(3).Remarkably,In_(4)SnSe_(4) inherited low thermal conductivity from its parent materials.To advance the potential thermoelectric property of In_(4)SnSe_(4),we systematically investigated its crystal structure and the origin of the intrinsic low thermal conductivity.In_(4)SnSe_(4) crystallized in a cubic phase(space group Pa3),with the lattice parameters of a=b=c=12.66Å.The anisotropy of IneSe bonds in the lattice determined the complex structure of In_(4)SnSe_(4) with 72 atoms in the primitive cell.More importantly,sound velocity and elastic properties unclosed the strong anharmonicity in In_(4)SnSe_(4),which contributed greatly to the low thermal conductivity.With first-principles calculations,it was found that the lone-pair electrons from In^(+)mainly caused the anharmonicity in the lattice.Additionally,Br was proved to be an effective dopant for In_(4)SnSe_(4) to improve the electrical transport properties.This work indicated that the complex wide-bandgap semiconductor In_(4)SnSe_(4) with cubic phase and intrinsic low thermal conductivity was a new promising thermoelectric material with appropriate doping.

Experimental realization of chiral Landau levels in two-dimensional Dirac cone systems with inhomogeneous effective mass

Chiral zeroth Landau levels are topologically protected bulk states.In particle physics and condensed matter physics,the chiral zeroth Landau level plays a significant role in breaking chiral symmetry and gives rise to the chiral anomaly.Previous experimental works on such chiral Landau levels are mainly based on three-dimensional Weyl degeneracies coupled with axial magnetic fields.Their realizations using two-dimensional Dirac point systems,being more promising for future applications,were never experimentally realized before.Here we propose an experimental scheme for realizing chiral Landau levels in a two-dimensional photonic system.By introducing an inhomogeneous effective mass through breaking local parity-inversion symmetries,a synthetic in-plane magnetic field is generated and coupled with the Dirac quasi-particles.Consequently,the zeroth-order chiral Landau levels can be induced,and the one-way propagation characteristics are experimentally observed.In addition,the robust transport of the chiral zeroth mode against defects in the system is also experimentally tested.Our system provides a new pathway for the realization of chiral Landau levels in two-dimensional Dirac cone systems,and may potentially be applied in device designs utilizing the chiral response and transport robustness.