Search

Coal tar pitch extract (CTPE) was carcinogenic and could cause occupational lung cancer. Hence, we explored the changes of protein molecules during CTPE-induced malignant transformation (MT) of immortalized human bronchial epithelial (BEAS-2B) cells and provided clues for screening early biomarkers of CTPE-associated occupational lung cancer. The MT model of BEAS-2B cells induced by CTPE with 15.0 μg/mL. Subsequently, the MT of the BEAS-2B cells was verified by morphological observation, cell proliferation test, plate colony formation assay, and cell cycle assay. At the end of the experiment, we explored the differentially expressed proteins (DEPs) by total protein tandem mass tags quantitative proteomics technique between DMSO40 cells and CTPE40 cells. It was found that the proliferation ability, and colony formation rate were enhanced, and the cell cycle was changed. Then, bioinformatics analysis showed that a total of 107 DEPs were screened between CTPE40 and DMSO40 cells, of which 74 were up-regulated and 33 were down-regulated. As a result, 6 hub proteins were screened by protein–protein interaction network analysis. The expression levels of COX7A2, COX7C, MT-CO2, NDUFB4, and NDUFB7 were up-regulated as well as the expression of RPS29 protein was down-regulated. In summary, we established an MT model in vitro and explored the changes in protein molecules. As a result, this study suggested that changes of protein molecules, including COX7A2, COX7C, NDUFB7, MT-CO2, NDUFB4, and RPS29, occurred at the stage of BEAS-2B cell malignancy following CTPE exposure, which provided key information for screening biomarkers for CTPE-related occupational lung cancer.

Lithium-sulfur (Li–S) batteries have aroused increasing interest and are gradually becoming a promising next-generation energy storage system. However, low electronic conductivity and shuttle effect of lithium polysulfides (LiPSs) severely hindered their commercial applications. To address the issues effectively, herein, a transition metal phosphate-VOPO4 was introduced into Li–S battery cathode, supplemented with carbon nanotubes (CNTs) as a conductive agent. Density functional theory method revealed that VOPO4 has strong polysulfides anchoring due to high abundant polar active site, which improved the electrochemical performances of sulfur cathode. At 0.5 C, the S/(VOPO4 + CNTs) electrode presents a discharge capacity of up to 912.8 mAh g−1 after 500 cycles. Even at 2 C, it also kept stable at 623.8 mAh g−1 after 800 cycles. The results showed that VOPO4 provided a helpful reference to have effectively expanded the applications and promoted the performance of Li–S batteries.

We report the systematic investigation of the effects of oxygen on the synthesis of 3p sub-family armchair graphene nanoribbons (3p-AGNRs), which revealed a strong catalytic effect with a reduction in the reaction temperature by approximately 180 K without degradation of the AGNRs. Poly(para-phenylene) (3-AGNR) was generated through Ullmann-type coupling of 4,4″-dibromo-p-terphenyl on Cu(111), which was then converted into wider 3p-AGNRs via lateral fusion. Scanning tunneling microscopy (STM) and X-ray photoelectron spectroscopy demonstrated the formation of different ribbons up to 12-AGNR, which contained regions exhibiting increased STM contrast that we attribute to the intercalation of Br atoms during lateral fusion.

Surface-confined reactions represent a powerful approach for the precise synthesis of low-dimensional organic materials. A complete understanding of the pathways of surface reactions would enable the rational synthesis of a wide range of molecules and polymers. Here, we report different reaction pathways of tetrathienylbenzene (T1TB) and its extended congener tetrakis(dithienyl)benzene (T2TB) on Cu(111), investigated using scanning tunneling microscopy, X-ray photoelectron spectroscopy, and density functional theory calculations. Both T1TB and T2TB undergo desulfurization when deposited on Cu(111) at room temperature. Deposition of T1TB at 453 K yields pentacene through desulfurization, hydrogen transfer, and a cascade of intramolecular cyclization. In contrast, for T2TB the intramolecular cyclization stops at anthracene and the following intermolecular C-C coupling produces a conjugated ladder polymer. We show that tandem desulfurization/C-C coupling provides a versatile approach for growing carbon-based nanostructures on metal surfaces.

Malaria remains a major public health issue in Nigeria, and Nigeria is one of the main sources of imported malaria in China. Antimalarial drug resistance is a significant obstacle to the control and prevention of malaria globally. The molecular markers associated with antimalarial drug resistance can provide early warnings about the emergence of resistance. The prevalence of antimalarial drug resistant genes and mutants, including PfK13, Pfcrt, Pfmdr1, Pfdhfr, and Pfdhps, was evaluated among the imported Plasmodium falciparum isolates from Nigeria in Henan, China, from 2012 to 2019. Among the 167 imported P. falciparum isolates, the wild-type frequency of PfK13, Pfcrt, Pfmdr1, Pfdhfr, and Pfdhps was 98.7, 63.9, 34.8, 3.1, and 3.1%, respectively. The mutation of PfK13 was rare, with just two nonsynonymous (S693F and Q613H) and two synonymous mutations (C469C and G496G) identified from four isolates. The prevalence of Pfcrt mutation at codon 74–76 decreased year-by-year, while the prevalence of pfmdr1 86Y also decreased significantly with time. The prevalence of Pfdhfr and Pfdhps mutants was high. Combined mutations of Pfdhfr and Pfdhps had a high prevalence of the quadruple mutant I51R59N108-G437 (39.0%), followed by the octal mutant I51R59N108-V431A436G437G581S613 (17.0%). These molecular findings update the known data on antimalarial drug-resistance genes and provide supplemental information for Nigeria.

As an emerging discipline in the intersection of chemistry and physics, on-surface chemistry has been at the forefront of surface science since its inception. On-surface chemistry has obvious differences from classical solution chemistry although they are closely related. Many reactions in solution become applicable in on-surface reactions under ultra-high vacuum conditions without the involvement of solvents. Furthermore, with the aid of surface confinement effects, a series of highly accurate, highly selective chemical reactions that are difficult to achieve in traditional solution reactions can be accomplished, which shows attractive potential for functional macromolecule design, synthetic chemistry, and new material fabrication. In this review, we present some representative on-surface reactions. By comparing the differences in reaction paths and products with traditional solution reactions, the characteristics of on-surface chemistry are epitomized. In addtion, we make a brief outlook for the opportunities and challenges of this novel synthetic tool facing in the future.

Traditional synthetic aperture radar (SAR) deceptive jamming can effectively generate deceptive scenes or false targets in SAR images. However, these false targets or scenes can be easily distinguished or eliminated by the multichannel SAR system. To interfere with the multichannel SAR, we first analyzed the results of SAR deceptive jamming generated by one transponder and two transponders against three-channel SAR- ground moving target indication (GMTI). Then, we propose a new deceptive jamming method against three-channel SAR-GMTI by using three synergetic transponders. By modulating each transponder with a complex coefficient, three synergetic transponders can generate false moving targets with the controllable radial velocity and located azimuth position in three-channel SAR-GMTI. Besides, in this paper, we also introduce an algorithm to deploy three transponders reasonably by utilizing the minimum condition number. In the end, a general architecture of multiple transponders deceiving multichannel SAR is given. The proposed method can not only generate deceptive false targets against multichannel SAR-GMTI, but also guide the production of a deceptive digital elevation model (DEM) against multichannel interferometric SAR (InSAR). Simulations verify the effectiveness of the proposed method.

The practical applications of lithium-sulfur (Li S) batteries remains remote because of low utilization of sulfur and short cycle life caused by low conductivity of sulfur, shuttle effect of lithium polysulfides and severe volume expansion. It is therefore exigent to rationally design an effective sulfur host. Here a novel sulfur host material--alpha molybdenum trioxide (α-MoO3) spheres are introduced into Li S battery cathode acting as lithium polysulfides absorbent and efficient matric of sulfur. The abundant oxygen atoms on the surface of α-MoO3, making it form chemical binding interactions with lithium polysulfides, which can effectively alleviate the dissolution of lithium polysulfides. Moreover, α-MoO3 as the matric of sulfur alleviates volume expansion of active sulfur and enhanced the utilization of sulfur, which results in improving the battery performances. As a result, S/α-MoO3 electrode with the sulfur content of 68 wt.% shows an initial discharge capacity of 1086.2 mAh g−1 and good capacity retention is obtained with 912.8 mAh g−1 after 400 cycles at 0.5 C. After 50 cycles at rates ranging from 0.1 to 2 C, the cell still returns a high specific capacity of 916.5 mAh g−1 at 0.5 C. The results demonstrate α-MoO3 was a promising sulfur host material for promoting the performances of Li S batteries with high sulfur content cathode.

Hollow TiO2/Sb/C spheres that nano Sb embedded into the interlayer between inner hollow TiO2 sphere and outer carbon layer, were designed, synthesized and investigated. The physical properties were studied by X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The electrochemical performances were acquired by discharge/charge cycles, rate cycles, cyclic voltammograms (CVs) and electrochemical impedance spectra (EIS). The results indicated that nano Sb embedded did not decline the cycle stability and rate property of TiO2/C anode, but its reversible capacity was increased by a large margin. Li+ diffusion coefficient of TiO2/Sb/C-2 and TiO2/Sb/C-1 reached to 4.76 × 10−16 cm2 s−1 and 4.10 × 10−16 cm2 s−1, while the value of TiO2/C was 2.46 × 10−16 cm2 s−1. At 1000 mA g−1, initial reversible capacity for TiO2/Sb/C-2 reached to 230.6 mAh g−1, and its capacity loss per cycle was only 0.0201% from 2nd to 1200th cycle. This work provided a conception to manufacture high capacity TiO2-based anodes for lithium ion battery.

Spinel LiMn2O4 was introduced into cathode for lithium‑sulfur (Li-S) batteries due to its stable structure, low price, good lithium ion conductivity and much active sites of Mn atoms which could capture polysulfides. Ultraviolet/visible absorption, Fourier transform infrared and X-ray photoelectron spectroscopies verified strong adsorption of Li2S6 by LiMn2O4. It could be explained by following possible adsorption mechanism that part Mn4 + on the surface of LiMn2O4 was reduced and transformed Mn3 + and Mn2 +, at the same time, some S62 − was oxidized and transformed Li2S6 − x (1

Lithium-sulfur (Li-S) batteries attract much attention due to its high specific capacity and energy density compared to lithium-ion batteries (LiBs). Herein, a novel composite named as (void/nano-Li 4 Ti 5 O 12 pieces)@C [(v/n-L)@C] was designed and prepared as a sulfur host. Spinel Li 4 Ti 5 O 12 here as a multifunctional additive played as polysulfide adsorbent agent and fast Li + conductor, and carbon shell was designed as electronic conductor, as well as volume barrier to limit the volume expansion caused by sulfur. As-prepared (S/nano-Li 4 Ti 5 O 12 pieces)@C [(S/n-L)@C] are core-shell spheres, which are about 200 nm in size. Nano-Li 4 Ti 5 O 12 and sulfur were coated by the outer carbon shell with a thickness of about 20 nm. The experimental results show that electrochemical performances of (S/n-L)@C cathode were enhanced effectively compared to S@C cathode. At 0.5C and 1C, the discharge capacity of (S/n-L)@C was 33.5% and 40.1% higher than that of S@C at 500 th cycle. Even at 2C, its capacity reached 600.9 mAh g −1 at 1000 th cycle. Li + conductivity of (S/n-L)@C was one order of magnitude higher than that of S@C, which was reach to 2.55 × 10 −8 S cm −1 . The experiment results indicate Li 4 Ti 5 O 12 plays a promotional role on electrochemical performances of sulfur cathode, especially for stable cycling performance and high rate performance.

Tetragonal FeSbO 4 with a coating carbon layer of ∼20 nm (FeSbO 4 /C) was synthesized via simple solid state method. The physical properties were investigated by X-ray diffraction (XRD), thermogravimetric (TG), scanning electron microscopy (SEM) and transmission microscopy (TEM). The electrochemical characteristics were studied via cyclic voltammetry (CV), electrochemical impedance spectra (EIS) and galvanostatic charge/discharge. Compared to FeSbO 4 , electronic conductivity of FeSbO 4 /C was obviously increased by coating a thin carbon layer. Furthermore, its reversible capacity and cycle performance were also improved. At 50 mA g −1 , the capacity of FeSbO 4 /C reached to 201.1 mAh g −1 at 200th cycle, while the value of FeSbO 4 was 107.2 mAh g −1 . The results indicate that FeSbO 4 /C is a potential anode material for lithium ion batteries.

Nano-Sn confined to matrixes for fabricating high capacity and long cycle life anodes has attracted extensive attention in recent years, but using Li+ conductor as structure stabilizer to construct matrixes have not been studied yet. Sn-based anodes using spinel Li4Ti5O12 as Li+ conductor and structure stabilizer can prolong the cycle life of electrodes, which is due to “zero strain” property and high Li+ conductivity coefficient of Li4Ti5O12. Herein, spherical (nano-Sn/Li4Ti5O12)@C was designed, synthesized and investigated, which was labeled as (n-Sn/L)@C. Nano-Sn and nano-Li4Ti5O12 pieces were mixed uniformly in inner carbon shell, where some vacuum space was beneficial for Sn expanding/shrinking during Li+ insertion/extraction. Moreover, Li+ diffusion coefficient of (n-Sn/L)@C-1 and (n-Sn/L)@C-2 was high as 6.09 × 10−8 and 9.47 × 10−9 cm2 s−1, whereas the value of Sn@C was 7.54 × 10−10 cm2 s−1. The charge capacity (corresponding to the reversible capacity on full cell) loss of per cycle of (n-Sn/L)@C-1 and (n-Sn/L)@C-2 from 1st to 350th cycle was only 0.081% and 0.094% at 500 mA g−1, while the value of Sn@C was 0.160%. The enhanced electrochemical performances of (n-Sn/L)@C benefited from intimate contact of nano-Li4Ti5O12 and nano-Sn within the carbon shell, and high Li+ conductivity of Li4Ti5O12.

The SAR jamming techniques have been extensively used in practice, including suppressive jamming and deceptive jamming, which reduce the capability of SAR. In this paper, an anti-interference method discriminating stationary false targets is proposed. This method utilizes displace phase-center antenna (DPCA) processing, based on dynamics of frequency-shifting deceptive jamming. It can display the stationary false targets and indicate their positions in SAR image. Simulation results verify the validation of this proposed method.

Investigating two-dimensional (2D) self-assembled structures of biological monomers governed by intermolecular interactions is a prerequisite to understand the self-assembly of more complex biomolecular systems. 5,6-Dihydroxyindole carboxylic acid (DHICA) is one of the building blocks of eumelanin – an irregular heteropolymer and the most common form of melanin which has potential applications in organic electronics and bioelectronics. By means of scanning tunneling microscopy, density functional theory and Monte Carlo calculations, we investigate DHICA molecular configurations and interactions underlying the multiple 2D patterns formed on Au(111). While DHICA self-assembled molecular networks (SAMNs) are dominated by the hydrogen bonding of carboxylic acid dimers, a variety of 2D architectures are formed due to the multiple weak interactions of the catechol group. The hydroxyl group also allows for redox reactions, caused by oxidation via O2 exposure, resulting in molecular rearrangement. The susceptibility of the molecules to oxidation is affected by their SAMNs architectures, giving insights on the reactivity of indoles as well as highlighting non-covalent assembly as an approach to guide selective oxidation reactions.

We report a new pathway to fabricate armchair graphene nanoribbons with five carbon atoms in the cross section (5-AGNRs) on Cu(111) surfaces. Instead of using haloaromatics as precursors, the 5-AGNRs are synthesized via a surface assisted decarboxylation reaction of perylene-3,4,9,10-tetracarboxylic dianhydride (PTCDA). The on-surface decarboxylation of PTCDA can produce extended copper–perylene chains on Cu(111) that are able to transform into graphene nanoribbons after annealing at higher temperatures (ca. 630 K). Due to the low yield (ca. 20%) of GNRs upon copper extrusion, various gases are introduced to assist the transformation of the copper–perylene chains into the GNRs. Typical reducing gases (H2 and CO) and oxidizing gas (O2) are evaluated for their performance in breaking aryl–Cu bonds. This method enriches on-surface protocols for the synthesis of AGNRs using non-halogen containing precursors.

Two-dimensional chirality transfer from self-assembled (SA) molecules to covalently bonded products was achieved via on-surface synthesis on Au(111) substrates by choosing 1,4-dibromo-2,5-didodecylbenzene (12DB) and 1,4-dibromo-2,5-ditridecylbenzene (13DB) as designed precursors. Scanning tunneling microscopy investigations reveal that their aryl-aryl coupling reaction occurs by connecting the nearest neighboring precursors and thus preserving the SA lamellar structure. The SA structures of 12(13)DB precursors determine the final structures of produced oligo-p-phenylenes (OPP) on the surface. Pure homochiral domains (12DB) give rise to homochiral domains of OPP, whereas lamellae containing mixed chiral geometry of the precursor (13DB) results in the formation of racemic lamellae of OPP.

Nowadays, energy storage systems have been considered as an effective way to meet the urgent demand for portable electronic products and electric vehicle industry, which requires the development of power sources that can provide high capacity as well as high safety, resulting in an increase on secondary batteries with excellent performances and non-pollution. Lithium-sulfur (Li-S) battery is considered as one of the most promising candidate batteries due to its high theoretical energy density, low cost and non-toxicity. Despite many advantages associated with Li–S battery, it is hard to be applied to commercial-scale production owing to its shuttle effect, insulating nature, agglomeration of sulfur, polysulfide dissolution and fast capacity decay during charge–discharge process. To meet these challenges, numerous characteristics of sulfur electrode have been designed, such as sufficient space to accommodate sulfur volume expansion, small dimensions of active material to avoid pulverization, and appropriate electrolyte additives to minimize the shuttle effect. According to previous studies, morphology of sulfur carriers has an important effect on electrochemical performances of Li–S battery. This review mainly aims at present status of different morphological sulfur carriers including carbon, metallic oxide, organic polymer and their composites, then summarizes their advantages, unresolved problems and common synthesis methods, respectively. At last, development and future prospects of Li–S battery are also presented.

While surface-confined Ullmann-type coupling has been widely investigated for its potential to produce π-conjugated polymers with unique properties, the pathway of this reaction in the presence of adsorbed oxygen has yet to be explored. Here, the effect of oxygen adsorption between different steps of the polymerization reaction is studied, revealing an unexpected transformation of the 1D organometallic (OM) chains to 2D OM networks by annealing, rather than the 1D polymer obtained on pristine surfaces. Characterization by scanning tunneling microscopy and X-ray photoelectron spectroscopy indicates that the networks consist of OM segments stabilized by chemisorbed oxygen at the vertices of the segments, as supported by density functional theory calculations. Hexagonal 2D OM networks with different sizes on Cu(111) can be created using precursors with different length, either 4,4″-dibromo-p-terphenyl or 1,4-dibromobenzene (dBB), and square networks are obtained from dBB on Cu(100). The control over size and symmetry illustrates a versatile surface patterning technique, with potential applications in confined reactions and host-guest chemistry.

Nano-Sn doped carbon-coated rutile TiO2 spheres (C-NS/TiO2-1 and C-NS/TiO2-2) as an improved TiO2-based anode for Li-ion batteries were in situ fabricated. The physical characteristics of the C-NS/TiO2 spheres were tested by X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Their electrochemical properties were characterized by cyclic voltammograms (CVs), electrochemical impedance spectra (EIS) and galvanostatic charge–discharge cycles. The results indicated that the as-prepared samples had particle sizes ranging from 1 to 5 μm and were composed of several small inner rutile TiO2 spheres, an outer mesoporous carbon coating layer and nano-Sn inhabited in the outer carbon layer. Their electronic conductivity was significantly enhanced owing to high electronic conductivity of the carbon layer and nano-Sn. Moreover, their reversibility capacity was also significantly improved due to the high specific capacity of nano-Sn. The C-NS/TiO2-1 and C-NS/TiO2-2 delivered a reversible capacity of 143.1 and 219.0 mA h g−1, respectively, after 200 cycles at a high current density of 500 mA g−1, which was increased by 52.0% and 132.6% compared to carbon-coated rutile TiO2 (C-TiO2).

Surface-assisted polymerization of alkanes is a remarkable reaction for which the surface reconstruction of Au(110) is crucial. The surface of (1×2)-Au(110) precovered with molecules can be completely transformed into (1×3)-Au(110) by introducing branched methylidene groups on both sides of the aliphatic chain (18, 19-dimethylidenehexatriacontane) or locally shifted into (1×3)-Au(110) under exposure to low-energy electrons (beam energy from 3.5 to 33.6 eV, for alkane dotriacontane). Scanning tunneling microscopy investigations demonstrate that alkane chains adsorbed on (1×3)-Au(110) are more reactive than on (1×2)-Au(110), presenting a solid experimental proof for structure–reactivity relationships. This difference can be ascribed to the existence of an extra row of gold atoms in the groove of (1×3)-Au(110), providing active sites of Au atoms with lower coordination number. The experimental results are further confirmed by density functional theory simulations.

VPO4 is introduced into the lithium sulfur battery system acting as efficient matrix for sulfur and absorbent for polysulfides. Adsorption experiments reveal that VPO4 has good adsorbability for polysulfides, which also has been demonstrated by ultraviolet/visible absorption spectrum. Fourier transform infrared spectroscopy further indicates that there exists chemical interaction between VPO4 and polysulfides. X-ray photoelectron spectroscopy study provided in-depth detailed analysis of chemical interaction. Furthermore, VPO4 as a matrix of sulfur which can alleviate volume expansion of sulfur and increase the utilization of active sulfur. The cell with the S/(VPO4 + CNTs) electrode exhibits 1056.0 mAh g−1 and 651.2 mAh g−1 at 0.5 C during the first and 500th cycles, which is much higher than 792.0 mAh g−1 and 486.5 mAh g−1 of the S/(AB+CNTs) electrode. Even at 2 C, the discharge capacity of the S/(VPO4 + CNTs) electrode shows 566.8 mAh g−1 after 800 cycles. These results demonstrate that VPO4 as efficient matrix for sulfur and absorbent for polysulfides is beneficial for improving electrochemical performances of lithium-sulfur battery.

Armchair graphene nanoribbons (AGNRs) with 8 and 10 carbon atoms in width (8- and 10-AGNRs) are synthesized on Au (111) surfaces via lateral fusion of nanoribbons that belong to different subfamilies. Poly-para-phenylene (3-AGNR) chains are pre-synthesized as ladder ribbons on Au (111). Subsequently, synthesized 5- and 7-AGNRs can laterally fuse with 3-AGNRs upon annealing at higher temperature, producing 8- and 10-AGNRs, respectively. The synthetic process, and their geometric and electronic structures are characterized by scanning tunneling microscopy/spectroscopy (STM/STS). STS investigations reveal the band gap of 10-AGNR (2.0 ± 0.1 eV) and a large apparent band gap of 8-AGNRs (2.3 ± 0.1 eV) on Au (111) surface.