Effect of point defects on the band alignment and transport properties of 1T-MoS2/2H-MoS2/1T-MoS2 heterojunctions.

Defects, which are an unavoidable component of the material preparation process, can have a significant impact on the properties of two-dimensional devices. In this work, we investigated theoretically the effects of different types and positions of point defects on band alignment and transport properties of metallic 1T-phase MoS2/semiconducting 2H-phase MoS2 junctions. We found that the Schottky barriers of junctions depend on the type of defects and their locations while showing anisotropic characteristics along the zigzag and armchair directions of 2H-phase MoS2. Moreover, defects in the central scattering region can generate local impurity states and introduce new transmission peaks, while defects at the interface do not generate impurity-state-related transmission peaks. Together, these defect-related peaks and Schottky barriers jointly affect the transport properties of the junctions. Understanding the complex behaviors of defects in devices can make the process of material preparation more efficient by avoiding harm.

Study on interface engineering and chemical bonding of the ReS2@ZnO heterointerface for efficient charge transfer and nonlinear optical conversion efficiency.

Rhenium sulfide (ReS2) has emerged as a promising two-dimensional material, demonstrating broad-spectrum visible absorption properties that make it highly relevant for diverse optoelectronic applications. Manipulating and optimizing the pathway of photogenerated carriers play a pivotal role in enhancing the efficiency of charge separation and transfer in novel semiconductor composites. This study focuses on the strategic construction of a semiconductor heterostructure by synthesizing ZnO on vacancy-containing ReS2 (VRe-ReS2) through chemical bonding processes. The ingeniously engineered built-in electric field within the heterostructure effectively suppresses the recombination of photogenerated electron-hole pairs. A direct and well-established interfacial connection between VRe-ReS2 and ZnO is achieved through a robust Zn-S bond. This distinctive bond configuration leads to enhanced nonlinear optical conversion efficiency, attributed to shortened carrier migration distances and accelerated charge transfer rates. Furthermore, theoretical calculations unveil the superior chemical interactions between Re vacancies and sulfide moieties, facilitating the formation of Zn-S bonds. The photoluminescence (PL) intensity is increased by the formation of VRe-ReS2 and ZnO heterostructure and the PL quantum yield of VRe-ReS2 is improved. The intricate impact of the Zn-S bond on the nonlinear absorption behavior of the VRe-ReS2@ZnO heterostructure is systematically investigated using femtosecond Z-scan techniques. The charge transfer from ZnO to ReS2 defect levels induces a transition from saturable absorption to reverse saturable absorption in the VRe-ReS2@ZnO heterostructure. Transient absorption measurements further confirm the presence of the Zn-S bond between the interfaces, as evidenced by the prolonged relaxation time (τ3) in the VRe-ReS2@ZnO heterostructure. This study offers valuable insights into the rational construction of heterojunctions through tailored interfacial bonding and surface/interface charge transfer pathways. These endeavors facilitate the modulation of electron transfer dynamics, ultimately yielding superior nonlinear optical conversion efficiency and effective charge regulation in optoelectronic functional materials.

Pure spin current in a cobalt phthalocyanine chain induced by the photogalvanic effect.

The development of methods for generating pure spin current at the molecular level is vital. In this work, we investigated how the spin-related photocurrent is produced in a cobalt phthalocyanine chain by the photogalvanic effect (PGE). Depending on how the magnetic moments of the left and right halves of the cobalt phthalocyanine chain are arranged, spin current can be generated. Both charge current and spin current are absent when the magnetic moments are arranged in parallel. Pure spin currents are generated when the magnetic moments are arranged in an antiparallel manner. Importantly, the pure spin current is robust to the polarization type and polarization angle. This characteristic results from the structure's charge density having spatial inversion symmetry but lacking that of the spin density.

Effect of vacancy defects on transport in all-phosphorene nanoribbon devices from first principles.

Defects in experimentally manufactured phosphorene nanoribbons (PNRs) occur unavoidably, affecting the functionality of PNR-based devices. In this work, we theoretically propose and investigate an all-PNR devices with single-vacancy (SV) defects and double-vacancy (DV) defects along the zigzag direction, accounting for both hydrogen passivation and non-passivation scenarios. We discovered that, in the case of hydrogen passivation, the DV defect can introduce in-gap states, whereas the SV defect can result in p-type doping. The unpassivated hydrogen nanoribbon exhibits an edge state with a considerable influence on the transport properties, which also masks the effect of defects on transport; furthermore, it demonstrates the phenomenon of negative differential resistance, whose occurrence and characteristics depend less on the presence or absence of defects.

P-Y/G@NHs sensitizes non-small cell lung cancer cells to radiotherapy via blockage of the PI3K/AKT signaling pathway.

Radioresistance represents a common phenomenon found in cancer treatment. Herein, the current study sought to evaluate the effects of a nanodrug delivery system of YSAYPDSVPMMS (YSA) peptide-modified gold nanoparticles-dextran-based hydrogel loaded with paclitaxel-succinic anhydride (P-Y/G@NHs) on non-small cell lung cancer (NSCLC) cell radiosensitivity. Firstly, utilizing the coupling reaction and layer-by-layer assembly technique, P-Y/G@NHs was prepared. The therapeutic effects of the P-Y/G@NHs in NSCLC cells in relation to the PI3K/AKT signaling pathway were examined by assessing the colony formation, apoptosis, and reactive oxygen species (ROS) generation of A549 cells under 10 Gy X-rays irradiation. Moreover, A549 tumor-bearing mice were generated to further validate the therapeutic effect in vivo. We confirmed the successful conjugation of the nanocomposite. Under 10 Gy X-rays irradiation, P-Y/G@NHs reduced the number of colonies of A549 cells, while inducing both cell apoptosis and ROS production. Moreover, P-Y/G@NHs enhanced the radiosensitivity of A549 cells by inhibiting the PI3K/AKT signaling pathway. In vivo fluorescence experiments validated that P-Y/G@NHs effectively-targeted and accumulated at the tumor site in nude mice, thus augmenting the radiosensitivity of tumors without significant immune toxicity or side effects. Conclusively, our findings highlighted that P-Y/G@NHs significantly enhanced the radiosensitivity of NSCLC cells by repressing the PI3K/AKT signaling pathway.

Omega-3 Polyunsaturated Fatty Acids Can Reduce C-Reactive Protein in Patients with Cancer: A Systematic Review and Meta-Analysis of Randomized Controlled Trials.

ABSTRACTSOmega-3 polyunsaturated fatty acids (PUFAs) possess anti-inflammatory properties. There is a lack of consensus regarding the effects of omega-3 PUFAs on C-reactive protein (CRP), a marker of systemic inflammation, in cancer patients. Herein, a meta-analysis of randomized controlled trials was conducted to evaluate the effects of omega-3 PUFAs on CRP levels in patients with cancer. PubMed and EMBASE were searched until May 2020 to identify randomized controlled trials that examined the effects of omega-3 PUFA administration on CRP levels in cancer patients. Standardized mean differences (SMDs) with their 95% confidence intervals (CIs) were calculated to determine the differences in omega-3 PUFA administration and control conditions. Seventeen eligible studies involving 916 cancer patients were included in this meta-analysis. Significant heterogeneity was present among individual studies (Pheterogeneity = 0.000; I2 = 74.5%). The overall SMDs of CRP levels between omega-3 PUFA administration and control conditions were 0.628 (95% CI: 0.342-0.914) and 0.456 (95% CI: 0.322-0.590) by the random-effect and fixed-effect models, respectively. Sources of heterogeneity were not found through subgroup and meta-regression analyses. Existing publication bias contributed slightly to the effect size. Omega-3 PUFAs can reduce systemic inflammation, as indicated by CRP levels in cancer patients. The use of omega-3 PUFAs is recommended for cancer patients due to their anti-inflammatory properties.

Computed tomography-guided cutting needle biopsy for lung nodules: when the biopsy-based benign results are real benign.

BACKGROUND: Computed tomography (CT)-guided cutting needle biopsy (CNB) is an effective diagnostic method for lung nodules (LNs). The false-negative rate of CT-guided lung biopsy is reported to be up to 16%. This study aimed to determine the predictors of true-negative results in LNs with CNB-based benign results. METHODS: From January 2011 to December 2015, 96 patients with CNB-based nonspecific benign results were included in this study as the training group to detect predictors of true-negative results. From January 2016 to December 2018, an additional 57 patients were included as a validation group to test the reliability of the predictors. RESULTS: In the training group, a total of 96 patients underwent CT-guided CNB for 96 LNs. The CNB-based results were true negatives for 82 LNs and false negatives for 14 LNs. The negative predictive value of the CNB-based benign results was 85.4% (82/96). Univariate and multivariate logistic regression analyses revealed that CNB-based granulomatous inflammation (P = 0.013, hazard ratio = 0.110, 95% confidential interval = 0.019-0.625) was the independent predictor of true-negative results. The area under the receiver operator characteristic (ROC) curve was 0.697 (P = 0.019). In the validation group, biopsy results for 47 patients were true negative, and 10 were false negative. When the predictor was used on the validation group, the area under the ROC curve was 0.759 (P = 0.011). CONCLUSIONS: Most of the CNB-based benign results were true negatives, and CNB-based granulomatous inflammation could be considered a predictor of true-negative results.

Microseismic Time Delay Estimation Method Based on Continuous Wavelet.

The microseismic signal is easily affected by observation noise and the inaccurate estimation of traditional methods will seriously reduce the location accuracy of the microseismic event. Therefore, based on the continuous wavelet spectrum and the similarity coefficient, a fast and efficient microseismic time delay estimation method is proposed. Firstly, the original signals are denoised by continuous wavelet transform. Subsequently, the time-frequency transform of the original signal by continuous wavelet transform, time-frequency signal extraction is the process of band-pass filtering, which can further reduce the influence of noise interference on the time delay estimation. Finally, we calculated the similarity between the time-frequency signals via the time domain and frequency domain integration. The similarity function is based on correlation and proposed according to the time-frequency transformation provided by the phase spectrum to evaluate the similarity between two noisy signals. The time delay estimation is determined by searching for the similarity function peak. The experimental results show the precision and accuracy of the method over the cross-correlation method and generalized cross-correlation phase transformation method, especially when the signal-to-noise ratio is low. Therefore, a new time delay estimation method for non-stationary random signals is presented in this paper.

Examining industrial air pollution embodied in trade: implications of a hypothetical China-UK FTA.

Very few developed economies have a full free trade agreement (FTA) with China. This study employs one GTAP model and builds an extended environmental multi-region input-output model to investigate a hypothetical China-UK FTA, concerning embodied industrial emissions of SO2, PM2.5, NOX, and NH3. The economic sectors are also classified based on their embodied pollution intensity and trade advantage index under various FTA scenarios. Results show that the UK's GDP and welfare and China's welfare will increase, along with changes in their trade structures. Overall, this FTA brings about larger net impacts on embodied emissions of SO2 than on PM2.5, NOX and NH3, and both countries are net importers of the latter three pollutants. Key sectors such as non-metallic mineral products, chemical products, and agriculture are inclined to become less competitive and less polluting under the FTA. The inclusion of agri-food sectors exhibits slight counteracting effects in general. The findings are of policy importance as they provide insights into how best to target key sectors, seeking a balance between trade development and environmental protection. Supplementary Information: The online version contains supplementary material available at 10.1007/s10668-022-02612-z.

Electronic structures of Zn1-xGaxO1-xNx and band offsets of the ZnO/Zn1-xGaxO1-xNx heterojunction across the entire concentration range from first principles.

Band offsets at the heterointerfaces play a key role in defining the functionality of optoelectronic devices. In this work, the band gaps of wurtzite Zn1-xGaxO1-xNx alloys and the band offsets of the lattice matched ZnO/Zn1-xGaxO1-xNx heterojunction across the entire concentration range of GaN were investigated by the modified Becke-Johnson (mBJ) semi-local exchange combined with the coherent potential approximation (CPA). The calculated band gaps of Zn1-xGaxO1-xNx alloys can be tuned by the concentration of the doping GaN and show a strong band gap bowing. The heterojunctions ZnO/Zn1-xGaxO1-xNx form either type I or type II band alignment by adjusting the concentration of GaN; especially, when the concentration is in the range of 0.8 < x < 0.97, the band gaps of Zn1-xGaxO1-xNx cover visible light, and the heterojunctions show type II band alignment, which would help to enhance the solar light adsorption ability and improve the carrier collection efficiency in the design and optimization of ZnO and GaN-based heterojunctions for the applications of optoelectronics and photocatalysis.

Probing an Individual Electron Spin State in a Quantum Dot with Spin Bias.

A quantum dot coupled to two electrodes with spin-dependent splitting of chemical potentials (spin bias) is proposed as a detector of an individual electron spin. Spin polarized transport properties through the quantum dot have been investigated theoretically by means of the nonequilibrium Green's function formalism. We found that the direction of current flow is dependent on the electronic spin state in quantum dot. Measuring the direction of the current flow through the devices, we can determine the direction of the electronic spin state in quantum dot. This proposed detector provides a practical and all electrical approach to detect the electronic spin state in quantum dot structure.

Spin-dependent quantum interference in Aharonov-Bohm ring embedded with two double-quantum-dot molecules.

The spin polarized transport properties through an Aharonov-Bohm ring embedded with a double quantum dot-molecule in each arm with Rashba spin-orbit (RSO) interaction is theoretically studied in the framework of the equation of motion of Green's function. Based on molecular state representation, the anti-resonance phenomenon in the conductance spectrum is readily explained. We found that the position of antiresonant peaks in conductance spectrum is determined by the interdot coupling strengths. Moreover, the magnitude of conductance of each spin component can be manipulated by the Rashba spin orbit interaction strength. Especially only one spin component electron can be allowed to transport through this structure by modulating the strength of RSO interaction properly.

Electronic transport through a benzene-shaped quantum dots system.

Based on the nonequilibrium Green function method, quantum transport through a benzene-shaped quantum dots system is studied. It is shown that the conductance spectrum is sensitive to the arrangement of energy levels of dots. When the energy levels of dots are mismatched, the conductance shows apparent asymmetric structure and striking novel conductance dips appear due to the interference between two distinct paths. The differential conductance as a function of magnetic flux always exhibits 2pi period. An overall suppression of differential conductance emerges for the condition that the levels of dots are all aligned and phi = (2n + 1)pi (n is an integer). In addition, the influence of temperature on the differential conductance is presented.

[Methylation of ER and ER gene and its significance in primary and relapsed/metastatic lesions of breast cancer].

OBJECTIVE: To investigate the different expressions of ER and ER gene status between primary and relapsed/metastatic lesions and their clinical significance. METHODS: ER and ER gene status of primary and relapse/metastatic breast cancer masked in 70 metastatic breast cancer patients were assessed by determination of methylation status by immunohistochemistry (IHC) and methylation specific polymerase chain reaction (MSP), respectively. RESULTS: Positive rate of ER in the primary breast cancers was 64.3%, and in the relapse/metastatic lesions was 41.4% (P < 0.05). There were six patients whose positive ER status was changed to negative, among them the ER gene status was changed from demethylation to hypermethylation in four cases. Another four patients with negative ER status changed to positive, and their ER gene hypermethylation changed to ER demethylation status. CONCLUSIONS: The discordance of ER expression status in primary and relapse/metastatic lesions of breast cancer might be related to DNA methylation status.

Transcription factor B-H2 regulates CYP9J34 expression conveying deltamethrin resistance in Culex pipiens pallens.

BACKGROUND: Mosquitoes are vectors of various diseases, posing significant health threats worldwide. Chemical pesticides, particularly pyrethroids like deltamethrin, are commonly used for mosquito control, but the emergence of resistant mosquito populations has become a concern. In the deltamethrin-resistant (DR) strain of Culex pipiens pallens, the highly expressed cytochrome P450 9 J34 (CYP9J34) gene is believed to play a role in resistance, yet the underlying mechanism remains unclear. RESULTS: Quantitative polymerase chain reaction with reverse transcription (qRT-PCR) analysis revealed that the expression of CYP9J34 was 14.6-fold higher in DR strains than in deltamethrin-susceptible (DS) strains. The recombinant production of CYP9J34 protein of Cx. pipiens pallens showed that the protein could directly metabolize deltamethrin, yielding the major metabolite 4'-OH deltamethrin. Through dual luciferase reporter assays and RNA interference, the transcription factor homeobox protein B-H2-like (B-H2) was identified to modulate the expression of the CYP9J34 gene, contributing to mosquito resistance to deltamethrin. CONCLUSIONS: Our findings demonstrate that the CYP9J34 protein could directly degrade deltamethrin, and the transcription factor B-H2 could regulate CYP9J34 expression, influencing the resistance of mosquitoes to deltamethrin. © 2023 Society of Chemical Industry.

Defect and interface/surface engineering synergistically modulated electron transfer and nonlinear absorption properties in MoX2 (X = Se, S, Te)@ZnO heterojunction.

Systematic interface and defect engineering strategies have been demonstrated to be an effective way to modulate the electron transfer and nonlinear absorption properties in semiconductor heterojunctions. However, the role played by defects and interfacial strain in electron transfer at the interface of the MoX2 (X = Se, S, Te)@ZnO heterojunction remains poorly understood. Herein, using the MoX2@ZnO heterojunction, we reveal that vacancies play a critical role in the interfacial electron transfer of heterojunctions. Specifically, we present the defect and interface engineering of the MoX2@ZnO heterojunction for controlled charge transfer and electron excitation-relaxation. The experimental characterization combined with first-principles calculations showed that the presence of defects promoted the transport of photogenerated carriers at the heterojunction interface, thereby inhibiting their rapid recombination. The DFT calculation confirmed that the electron band structure, density of states and charge density distribution in the system changed after the formation of Mo-O bonds. On the basis of defects and interfacial stress and the effective charge transfer, the MoX2@ZnO heterojunction exhibited excellent excitation and emission behaviors. The nonlinear optical regulation behavior of TMDs is expected to be realized with the help of the defects and interface/surface synergistically modulated effect of ZnO nanoparticles. The local strain generation on the MoX2@ZnO heterojunction boundary provides a new method for the design of new heterogeneous materials and will be of great significance to investigate the contact physical behavior and application of metals and two-dimensional (2D) semiconductors. This work provides some inspiration for the construction of heterojunctions with rich defects and surface/interface charge transfer channels to promote tunable electron transfer dynamics, thereby achieving a good nonlinear optical conversion efficiency and efficient charge separation in optoelectronic functional materials.

Biofilms in plastisphere from freshwater wetlands: Biofilm formation, bacterial community assembly, and biogeochemical cycles.

Microorganisms can colonize to the surface of microplastics (MPs) to form biofilms, termed "plastisphere", which could significantly change their physiochemical properties and ecological roles. However, the biofilm characteristics and the deep mechanisms (interaction, assembly, and biogeochemical cycles) underlying plastisphere in wetlands currently lack a comprehensive perspective. In this study, in situ biofilm formation experiments were performed in a park with different types of wetlands to examine the plastisphere by extrinsic addition of PVC MPs in summer and winter, respectively. Results from the spectroscopic and microscopic analyses revealed that biofilms attached to the MPs in constructed forest wetlands contained the most abundant biomass and extracellular polymeric substances. Meanwhile, data from the high-throughput sequencing showed lower diversity in plastisphere compared with soil bacterial communities. Network analysis suggested a simple and unstable co-occurrence pattern in plastisphere, and the null model indicated increased deterministic process of heterogeneous selection for its community assembly. Based on the quantification of biogeochemical cycling genes by high-throughput qPCR, the relative abundances of genes involving in carbon degradation, carbon fixation, and denitrification were significantly higher in plastisphere than those of soil communities. This study greatly enhanced our understanding of biofilm formation and ecological effects of MPs in freshwater wetlands.

Crystalline modulation of zirconia for efficient nitrate reduction to ammonia under ambient conditions.

Zirconia as a polycrystalline catalyst can be effectively tuned by doping low-valence elements and meanwhile form abundant oxygen vacancies. Herein, the crystalline structures of zirconia are modulated by scandium doping and proposed as a robust catalyst for nitrate reduction to ammonia. The tetragonal zirconia achieves a maximum ammonia yield of 16.03 mg h-1 mgcat.-1, superior to the other crystal forms. DEMS tests unveil the reaction pathway and theoretical calculations reveal the low free energy of -0.22 eV for nitrate adsorption at the tetragonal zirconia.

Superior anticancer efficacy of curcumin-loaded nanoparticles against lung cancer.

Curcumin (CM) has anticancer potential for several cancers and blocks several steps in the carcinogenesis process. However, the clinical application of CM is greatly limited due to its low effects in vivo resulted from its poor solubility and pharmacokinetics. This raises the possibility of taking CM as a novel model drug in a new nanoparticle-based delivery system. In this study, CM-loaded nanoparticles were prepared from three kinds of amphilic methoxy poly(ethylene glycol) (mPEG)-polycaprolactone (PCL) block copolymers. It was noted that CM-loaded nanoparticles prepared from mPEG10k-PCL30k showed not only the highest loading efficiency, but also the most sustained release pattern. In vitro studies showed that CM was effectively transported into A549 cells by nanoparticles and localized around the nuclei in the cytoplasm. In addition, the cytotoxicity of CM-loaded nanoparticles with mEPG10k-PCL30k as a drug carrier was in a dose- and time-dependent manner in A549 cells. Further apoptotic staining results demonstrated the superior pro-apoptotic effect of CM-loaded nanoparticles over free drug. Data in this study not only confirmed the potential of CM in treating lung cancer, but also offered an effective way to improve the anticancer efficiency of CM through the nano-drug delivery system.

Ce6/PTX2-NP/G@NHs Confer Radiosensitivity in Non-Small Cell Lung Cancer via Promotion of Apoptotic Body-Mediated Neighboring Effects.

This study fabricates a nanoparticle delivery system of gold nanoparticles-dextran nanoparticles loaded with hypoxia-activated paclitaxel dimeric prodrug nanoparticles (PTX2-NP) and photosensitizer chlorin e6/paclitaxel-nanoparticle/gold@N-(2-hydroxypropyl) (Ce6/PTX2-NP/G@NHs) and analyzed the possible molecular mechanism for enhancing the radiosensitivity of non-small cell lung cancer (NSCLC). Ce6/PTX2-NP/G@NHs were prepared by a coupling reaction and dextran inclusion, followed by characterization using spectroscopy techniques. The cellular uptake and cytotoxicity of Ce6/PTX2-NP/G@NHs were analyzed. Radiosensitizing effects of the nanoparticles were evaluated by determining the malignant phenotypes and reactive oxygen species production of A549 cells and PI3K/AKT pathway-related proteins under 685 nm laser irradiation. A549 tumor-bearing nude mice were modeled to further confirm the radiosensitizing effect. Ce6/PTX2-NP/G@NHs were effectively internalized by A549 cells, producing cytotoxicity under laser irradiation. Ce6/PTX2-NP/G@NHs reduced cell viability, clonogenic potential, migration, and invasion along with reactive oxygen species (ROS) production while promoting apoptosis in A549 cells under laser irradiation. By inhibiting the PI3K/AKT pathway, Ce6/PTX2-NP/G@NHs increased the sensitivity of A549 cells to radiotherapy where apoptotic body (ApoBD)-mediated neighboring effects also played a key role. Ce6/PTX2-NP/G@NHs accumulated in tumor sites of nude mice and enhanced the radiosensitivity of NSCLC. Ce6/PTX2-NP/G@NHs showed no obvious toxicity or side effects in vivo. Collectively, the new Ce6/PTX2-NP/G@NHs nanoparticle delivery system can enhance the radiosensitivity of NSCLC via the promotion of ApoBD-mediated neighboring effects and inactivation of the PI3K/AKT pathway.