Ultra-wide band gap and wave attenuation mechanism of a novel star-shaped chiral metamaterial

A novel hollow star-shaped chiral metamaterial(SCM)is proposed by incorporating chiral structural properties into the standard hollow star-shaped metamaterial,exhibiting a wide band gap over 1500 Hz.To broaden the band gap,solid single-phase and two-phase SCMs are designed and simulated,which produce two ultra-wide band gaps(approximately 5116 Hz and 6027 Hz,respectively).The main reason for the formation of the ultra-wide band gap is that the rotational vibration of the concave star of two novel SCMs drains the energy of an elastic wave.The impacts of the concave angle of a single-phase SCM and the resonator radius of a two-phase SCM on the band gaps are studied.Decreasing the concave angle leads to an increase in the width of the widest band gap,and the width of the widest band gap increases as the resonator radius of the two-phase SCM increases.Additionally,the study on elastic wave propagation characteristics involves analyzing frequency dispersion surfaces,wave propagation directions,group velocities,and phase velocities.Ultimately,the analysis focuses on the transmission properties of finite periodic structures.The solid single-phase SCM achieves a maximum vibration attenuation over 800,while the width of the band gap is smaller than that of the two-phase SCM.Both metamaterials exhibit high vibration attenuation capabilities,which can be used in wideband vibration reduction to satisfy the requirement of ultra-wide frequencies.

Laser spectroscopy imaging technique coupled withnanomaterials for cancer diagnosis: A review

Laser spectroscopic imaging techniques have received tremendous attention in the-eld of cancer diagnosis due to their high sensitivity,high temporal resolution,and short acquisition time.However,the limited tissue penetration of the laser is still a challenge for the in vivo diagnosis of deep-seated lesions.Nanomaterials have been universally integrated with spectroscopic imaging techniques for deeper cancer diagnosis in vivo.The components,morphology,and sizes of nanomaterials are delicately designed,which could realize cancer diagnosis in vivo or in situ.Considering the enhanced signal emitting from the nanomaterials,we emphasized their combination with spectroscopic imaging techniques for cancer diagnosis,like the surface-enhanced Raman scattering(SERS),photoacoustic,fluorescence,and laser-induced breakdown spectroscopy(LIBS).Applications ofthe above spectroscopic techniques offer new prospectsfor cancer diagnosis.

Involvement of lncRNAs in the tumor microenvironment:a new property of tumor immunity

Immune checkpoint blockade(ICB)has achieved durable clinical responses and has significantly improved the overall survival of cancer patients1.Among the ICB agents,programmed death 1(PD-1)/programmed death ligand 1(PD-L1)antibodies are used to treat various human tumors by blocking PD-1/PD-L1 signaling.Impressive response rates with low autoimmune toxicity have been reported in 20%–30%of non-selected patients1;however,most patients fail to respond to PD-1/PD-L1 blockade or acquire resistance during therapy through unknown mechanisms1.

Development of a poly(arylene sulfide sulfone)antibacterial electrospun film as a skin wound dressing application

Tissue engineering has become a hot issue for skin wound healing because it can be used as an alternative treatment to traditional grafts.Nanofibrous films have been widely used due to their excellent properties.In this work,an organic/inorganic composite poly(arylene sulfide sulfone)/ZnO/graphene oxide(PASS/ZnO/GO)nanofibrous film was fabricated with the ZnO nano-particles blending in an electrospun solution and post-treated with the GO deposition.The optimal PASS/ZnO/GO nanofibrous film was prepared by 2%ZnO nanoparticles,3.0g/mL PASS electrospun solution,and 1%GO dispersion solution.The morphology,hydrophilicity,mechanical property,and cytotoxicity of the PASS/ZnO/GO nanofibrous film were character-ized by using scanning electron microscopy,transmission electron microscope,water contact angle,tensile testing,and a Live/Dead cell staining kit.It is founded that the PASS/ZnO/GO nanofibrous film has outstanding mechanical properties and no cytotoxicity.Furthermore,the PASS/ZnO/GO nanofibrous film exhibits excellent antibacterial activity to both Escherichia coli and Staphylococcus aureus.Above all,this high mechanical property in the non-toxic and antibacterial nanofibrous film will have excellent application prospects in skin wound dressing.

Applications of Raman spectroscopy in two-dimensional materials

At present,two-dimensional(2D)materials have shown great application potential in numerous fields based on their physical chemical and electronic properties.Raman spectroscopy and de-rivative techniques are effective tools for characterizing 2D materials.Raman spectroscopy conveys lots of knowledge on 2D materials,including layer number,doping type,strain and interlayer coupling.This review summarized advanced applications of Raman spectroscopy in 2D materials.The challenges and possible applied directions of Raman spectroscopy to 2D materials are discussed in detail.

Angular-based spatially resolved laser-induced breakdown spectroscopy: a new technique for the effective enhancement of signals without an external time delay system

In this study, we developed a novel angularbased spatially resolved laser-induced breakdown spectroscopy(ABSR-LIBS) technique. This new method allows the spatially resolved spectroscopic properties of laserinduced plasma to be investigated using different angles and polar distances with a spatially adjustable fiber optics probe. The experimental evaluations suggested that the intensity of the Al signal distributions in the ‘‘side-view''depended greatly on the angle of the collection probe. The location of a collection probe at 50° would facilitate efficient spectral collection and minimize the disturbance of the plasma plume. The spectral signals in the plasma emissions had different distribution at various polar distances using the same collection angle, and the highest signal intensity was observed between 15 and 35 mm polar distances. This ABSR-LIBS technique improved both the LIBS signal and the maximum emission intensity of Al atoms by several times at the best spatial position in our experimental conditions. Furthermore, we successfully obtained well-resolved line emission spectroscopy signals without any external time delay using a nongated spectrometer based on the ABSR-LIBS system. We consider that the ABSR-LIBS technique has great potential for obtaining new insights with laser-induced plasma instruments and it could facilitate the development of a low-cost instrument.

Direct Introduction of EthoxycarbonyldifluoromethyI-Group to Heteroarenes with Ethyl Bromodifluoroacetate via Visible-Light Photocatalysis

A mild and versatile approach for the direct introduction of ethoxycarbonyldifluoromethyl-group to heteroarenes via visible-light photocatalysis has been developed. The new photoredox protocol has enabled the difluoromethylenation of heteroarenes containing a wide range of common functional groups under mild conditions.

lncRNA HITT Inhibits Lactate Production by Repressing PKM2 Oligomerization to Reduce Tumor Growth and Macrophage Polarization

Lactic acid acidifies the tumor microenvironment and promotes multiple critical oncogenic processes,including immune evasion.Pyruvate kinase M2(PKM2)is a dominant form of pyruvate kinase(PK)expressed in cancers that plays essential roles in metabolic reprograming and lactate production,rendering it as an attractive therapeutic target of cancer.However,the mechanism underlying PKM2 regulation remains unclear.Here,we show that long noncoding RNA(lncRNA)HIF-1αinhibitor at transcription level(HITT)inhibits lactate production in a PKM2-dependent manner.Mechanistically,it physically interacts with PKM2 mapped to a region that has been involved in both dimer(less-active)and tetramer(more-active)formation,inhibiting PKM2 oligomerization and leading to dramatic reduction of PK activity.Under glucose starvation,HITT was reduced as a result of miR-106 induction,which subsequently facilitates PKM2 oligomerization and increases vulnerability to apoptosis under glucose starvation stress.In addition,the interaction also reduces lactate secretion from cancer cells,which subsequently polarizes macrophages toward an M2-like anti-inflammatory phenotype and thus possibly contributes to immune escape in vivo.This study highlights an important role of an lncRNA in regulating PKM2 activity and also reveals a metabolic regulatory effect of PKM2 on macrophage polarization.