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Based on the actual operation scenario of metro, this paper proposes an uneven parameter stray current distribution model. The model combines the calculation method of multi-section traction power supply of metro and establishes an uneven parameter stray current distribution model in different calculation domains with the metro operation position and the traction substation position as the boundary points. The improved dynamic boundary conditions were used to calculate the model. Compared with the experimental data, the average maximum deviation between the two was 0.677. Meanwhile, the dynamic space–time distribution characteristics of stray current and the change law of rail-to-ground voltage were obtained through simulation analysis. In addition, the calculation model for ground potential gradient distribution under stray current interference was established by discretizing stray currents within each calculation domain, and the characteristics of ground potential gradient distribution were simulated and analyzed. The results showed that the distribution period of stray current was approximately equal to the headway, and the waveform change lagged behind the rail-to-ground voltage. The fluctuation degree of ground potential gradient was obviously affected by the length of power supply interval and train operation conditions. [ABSTRACT FROM AUTHOR]

CAG is the most common precancerous disease of gastric cancer, which belongs to a kind of chronic gastritis. CAG is in close association with gastric cancer, which makes itself a critical node clinically in cancer prevention and treatment. Curcumol is a main active monomer in Fuzheng Huowei decoction, which has the properties of antioxidant, antiviral, and antitumor. In this study, the expression of SDF-1α/CXCR4/NF-κB was detected by in vivo and in vitro methods. Then, we found that the expressions of NF-κB, SDF-1α, CXCR4, and p-NF-κB were decreased in the curcumol treatment group. Curcumol inhibited gastric cancer cells' viability, migration, and invasion and induced their apoptosis. After adding the lentivirus overexpressing SDF-1α to the curcumol treatment group, it was found that SDF-1α, CXCR4, NF-κB, and p-NF-κB protein expressions were all increased, and the effect of curcumol on gastric cancer cells was reversed. In the nude mouse experiment, the tumor volume in the curcumol + SDF-1α group was the largest, and the tumor volume in the Fuzheng Huowei decoction + NC group was the smallest. In conclusion, curcumol effectively protects gastric tissue and inhibits the viability of gastric cancer cells, and curcumol regulates SDF-1α/CXCR4/NF-κB to play a therapeutic role in chronic atrophic gastritis and gastric cancer. [ABSTRACT FROM AUTHOR]

CAG is an essential procession of the transformation from gastritis into gastric cancer. A series of timely moves of diagnosis, treatment, and monitoring towards CAG to anticipate the potential population at risk of gastric cancer is an effective means to prevent gastric cancer occurrence. The main active monomer in Fuzheng Huowei Decoction is Curcumol, which is an indispensable ingredient in the treatment to CAG and gastric cancer. In this study, the CAG model, in vitro cultured gastric cancer cells, and participating nude mice were treated with Curcumol, and alterations in SDF-1α/CXCR4/VEGF expression were estimated using the assays of immunohistochemistry and Western blot. MTT, flow cytometry, transwell, HE staining, and tumor volume determination were applied for the verification of the regulatory effects of Curcumol on CAG and gastric cancer cells. The results showed that the expressions of VEGF, SDF-1α, CXCR4, and CD34 decreased in our CAG model with Curcumol treatment. Curcumol is in procession of an inhibitory effect toward the activity, migration, and invasion of gastric cancer cells, and it would also result in gastric cancer cells' apoptosis. We subsequently added SDF-1α overexpressing lentivirus to the Curcumol-treated group and found that the expressions of SDF-1α, CXCR4, and VEGF protein increased, and the inhibitory effect of Curcumol on gastric cancer cells was withdrawn. Our nude mouse experiment showed that Curcumol + SDF-1α group ended up with the largest tumor volume, while Fuzheng Huowei + NC group was with the smallest tumor volume. In conclusion, Curcumol is able to effectively protect the gastric tissue and suppress gastric cancer cells' viability. Curcumol functions as a therapeutic factor in chronic atrophic gastritis and gastric cancer by downregulating SDF-1α/CXCR4/VEGF expression. [ABSTRACT FROM AUTHOR]

The large-scale use of pesticides such as organophosphate pesticides (OPPs) and organochlorine pesticides (OCPs) has led to serious environmental problems worldwide, and their high toxicity could cause serious damage to human health. It is crucial to remove and track them precisely in the environment and food resources. As novel nanomaterials, metal–organic frameworks (MOFs) have attracted significant attention in the fields of adsorption and luminescence sensing due to their rich topology, tunable pore size and shape, high surface area, and abundant active sites. Luminescent metal–organic frameworks (LMOFs) have sprung up as great potential chemical sensors to detect pesticides with fast response, high sensitivity, high selectivity and easy operation. Therefore, in this highlight, we focus on recent progress of MOFs in sensing and adsorbing pesticides, as well as in the possible mechanism of sensing, so as to attract more attention to pesticide detection and adsorption. [ABSTRACT FROM AUTHOR]

To establish and preliminarily validate an individualized reference of carotid stiffness quantified by ultrafast pulse wave velocity (ufPWV), our study included 225 healthy individuals in the modeling cohort and 628 individuals in the validation cohort. All participants underwent assessment of carotid intima-media thickness (cIMT), pulse wave velocity-beginning of systole and pulse wave velocity-end of systole (PWV-ES). A threshold equation of estimated PWV-ES was obtained by multiple linear regression analysis in the modeling cohort as follows: estimated PWV-ES (m/s) = 0.080 × age (y) + 0.767 × low-density lipoprotein (mmol/L) + 0.040 × systolic blood pressure (mm Hg) + 0.372 × sex (male = 1, female = 0) - 2.803. With this equation, the validation cohort was divided into the low PWV-ES (actual PWV-ES ≤ estimated PWV-ES) and high PWV-ES (actual PWV-ES > estimated PWV-ES) groups. A clear boundary was found to be present between the low PWV-ES and high PWV-ES groups in the validation cohort. Participants with increasing PWV-ES increased with age gradually. We further subdivided participants into cIMT subgroups using a cutoff thickness of 0.050 cm. Diagnostic performance analysis revealed that the sensitivity and specificity of the threshold equation were 78.9% and 73.9%, respectively. We established and validated a novel individualized reference equation for estimated PWV-ES, which can likely expand the application of prospective ufPWV assessment. [ABSTRACT FROM AUTHOR]

The detection of water pipeline leakage is important to ensure that water supply networks can operate safely and conserve water resources. To address the lack of intelligent and the low efficiency of conventional leakage detection methods, this paper designs a leakage detection method based on machine learning and wireless sensor networks (WSNs). The system employs wireless sensors installed on pipelines to collect data and utilizes the 4G network to perform remote data transmission. A leakage triggered networking method is proposed to reduce the wireless sensor network's energy consumption and prolong the system life cycle effectively. To enhance the precision and intelligence of leakage detection, we propose a leakage identification method that employs the intrinsic mode function, approximate entropy, and principal component analysis to construct a signal feature set and that uses a support vector machine (SVM) as a classifier to perform leakage detection. Simulation analysis and experimental results indicate that the proposed leakage identification method can effectively identify the water pipeline leakage and has lower energy consumption than the networking methods used in conventional wireless sensor networks. [ABSTRACT FROM AUTHOR]

Since the beginning of the coronavirus disease 2019 (COVID-19) pandemic, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the causative agent of COVID-19, continues to mutate and generates new variants with increasingly severe immune escape, urging the upgrade of COVID-19 vaccines. Here, based on a similar dimeric RBD design as our previous ZF2001 vaccine, we developed a novel broad-spectrum COVID-19 mRNA vaccine, SWIM516, with chimeric Delta-BA.2 RBD dimer delivered by lipopolyplex (LPP). Unlike the popular lipid nanoparticle (LNP), this LPP-delivered mRNA expresses only in the injection site, which avoids potential toxicity to the liver. We demonstrated the broad-spectrum humoral and cellular immunogenicity of this vaccine to Delta and Omicron sub-variants in naïve mice and as booster shots. When challenged with Delta or Omicron live virus, vaccinated hACE2 transgenic mice and rhesus macaques were both protected, displaying significantly reduced viral loads and markedly relieved pathological damages. We believe the SWIM516 vaccine qualifies as a candidate for the next-generation broad-spectrum COVID-19 vaccine. Author summary: mRNA vaccines have demonstrated their advantages in immunogenicity and development speed during the coronavirus disease 2019 (COVID-19) pandemic. However, the significant immune escape caused by the evolution of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has presented a considerable challenge to the effectiveness of COVID-19 vaccines. Moreover, concerns have arisen about the potential liver toxicity associated with the lipid nanoparticles (LNP) used in approved mRNA vaccines, raising questions about their safety. To address these challenges, we have developed the SWIM516 vaccine, which utilizes a chimeric Delta-BA.2 RBD dimer immunogen to provide broad-spectrum protection and a lipopolyplex (LPP) delivery system to enhance safety. This vaccine has demonstrated its ability to induce broad-spectrum immunogenicity in mice and offers protection to both mice and monkeys when exposed to live SARS-CoV-2 challenges, qualifying it as a next-generation broad-spectrum COVID-19 vaccine. [ABSTRACT FROM AUTHOR]

The selective detection of toxic Hg(II) ions is of great significance for industrial processing and environmental remediation. Herein, a novel copper(I) metal–organic framework [Cu3Cl3(bimpy)3] (1) (bimpy = 3,5-bis(1-imidazolyl)pyridine) was constructed by a solvothermal method. Single-crystal X-ray analysis shows that complex 1 is a 2-fold interpenetrated three-dimensional structure with a tfj topology, exhibiting high thermal stability and water stability. Complex 1 was used to modify a glassy carbon electrode (GCE) for the determination of Hg(II) in 0.1 M phosphate buffer solution (PBS) at pH = 7.0. However, on account of the poor electron-conductive property of complex 1, acetylene black (AB) was introduced into complex 1 to improve its electrochemical sensing activity. The electrochemical sensing property of AB and the complex 1 modified GCE was investigated by cyclic voltammetry and chronoamperometric tests. Under the optimal conditions, AB/complex 1/GCE exhibits a high sensitivity of 16.85 μA μM−1 cm−2 and a low limit of detection of 1.01 nM in the wide linear range from 2.0 μM to 64 μM. AB/complex 1/GCE could also be applied for detecting Hg(II) ions in tap water and river water. The aptasensor provides a valuable tool with satisfactory anti-interference, reproducibility, repeatability, simple preparation, and satisfactory applicability for the sensing of Hg(II) ions. [ABSTRACT FROM AUTHOR]

As an important biomarker, the level of reduced glutathione in serum is vital for human health. A novel 3D metal–organic framework with excellent photoluminescence properties, formulated as [Zn3(TNB)(DPE)2]·2H2O·DMF (1) (H3TNB = 4,4′,4′′-nitrilotribenzoic acid and DPE = 1,2-di(4-pyridyl)ethylene), was constructed by a solvothermal reaction. Complex 1 exhibits high water stability and pH stability in aqueous solution. It can detect Fe3+ and Pb2+ as a "turn-off" fluorescent probe in PBS solution with high sensitivity and selectivity. The detection limits for Fe3+ and Pb2+ are about 3.40 × 10−7 M and 4.59 × 10−7 M, respectively. Compared to Pb2+, Fe3+ has stronger oxidizability, and can be reduced to Fe2+ with the addition of a reductant, causing the fluorescence intensity of the Fe3+@1 system to significantly recover while that of the Pb2+@1 system has little change. Thus, the Fe3+@1 system exhibits a fluorescence "turn-on" signal after adding reduced glutathione (GSH) due to the reduction reaction, which indicates that complex 1 can be designed as an "on–off–on" fluorescent probe to detect Fe3+ ions and reduced GSH. The mechanism for fluorescence recovery is the elimination of the FRET process between Fe3+ and complex 1. In view of this reversible detection event, a two-input molecular logic gate was constructed. In addition, the "on–off–on" fluorescent sensor can be successfully applied to detection of reduced GSH in serum and fruits and vegetables with a high recovery range and low relative standard deviations (RSDs). To the best of our knowledge, this is the first example of a MOF-based probe for reduced GSH recognition by fluorescence "on–off–on" in PBS solution. [ABSTRACT FROM AUTHOR]

[Display omitted] The continuous evolution of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has resulted in a significant number of variants, particularly with the emergence of Omicron with many sub-variants. These variants have exhibited increased immune escape, leading to reduced efficacy of existing vaccines and therapeutic antibodies. Given the diminished cross-neutralization observed among these variants, it is plausible that SARS-CoV-2 has developed multiple serotypes. As the major antigenic site, the receptor-binding domain (RBD) of viral spike (S) protein was chosen for serotyping. We selected 23 representative variants, including pre-Omicron variants and Omicron sub-variants, and classified them into five serotypes based on systematic evaluation of the antigenicities of their RBDs. Each serotype includes several genetically distinct variants. Serotype-I encompasses all pre-Omicron variants (with two subtypes), while the remaining four serotypes are all comprised of Omicron sub-variants at different stages of evolution. We propose that these serotypes can serve as a foundation for rapid classification of newly emerging SARS-CoV-2 variants, and guide the development of future broad-spectrum vaccines and neutralizing antibodies against the coronavirus disease 2019 (COVID-19). [ABSTRACT FROM AUTHOR]

A dual-emission fluorescence sensor based on RhB@ZrT-1-OH exhibits ultra-high sensitive detection for malachite green and glycine in water and practical samples. [Display omitted] • RhB@ZrT-1-OH composite with the dual emission peaks was constructed. • RhB@ZrT-1-OH as a ratiometric fluorescence probe can detect malachite green. • RhB@ZrT-1-OH can be utilized as a "turn-on" fluorescence sensor to detect glycine. • Mechanisms of luminescence sensing were investigated in detail. RhB@ZrT-1-OH composite was constructed by introduction of Rhodamine B (RhB) into the cages of zirconium-based metal–organic cage that had two fluorescence emission peaks at 466 and 612 nm upon excitation at 327 nm. The dual-emission fluorescence sensor exhibits ultra-high sensitive detection for malachite green (MG) and glycine (Gly) in phosphate buffer solution (pH = 6.86). RhB@ZrT-1-OH as a ratiometric fluorescence probe was applied to detect MG with a low LOD of 0.2879 μM and presented obvious fluorescence visual changes from orange to purple to blue under 254 nm UV–vis lamp. Moreover, RhB@ZrT-1-OH also can be utilized as a "turn-on" fluorescence sensor to recognize Gly with a low LOD of 0.3747 μM and exhibits fluorescence color changes from orange to pink to purple. Notably, the corresponding test papers for sensing MG and Gly were designed for recognize the concentration of MG and Gly. Furthermore, the dual-emission fluorescence sensor can be used to detect MG and Gly in fish and human serum with high sensitivity and reliable. The possible detecting mechanisms of RhB@ZrT-1-OH for sensing MG and Gly were detailedly explored. [ABSTRACT FROM AUTHOR]

Based on the results of the National Survey of Peat Resources (1983-1985) and the investigation results on the peatlands of China, the storage and density of the organic carbon in the peatlands of China were estimated. The total organic carbon storage (OCS) of the peatlands in China, including bare peatlands and buried peatlands, are 1.503 × 10 t, unevenly distributed over 30 provincial level administrative units and 16 climatic zones. Peatland organic carbon storage (POCS) in Sichuan (6.45 × 10 t) and Yunnan provinces (2.91 × 10 t) is the highest, accounting for 62.29% of the total POCS. Humid zone of plateau has the highest POCS of 7.14 × 10 t, especially in the Zoigê Plateau, where the POCS is 6.30 × 10 t, accounting for 41.92% of the total POCS of China. The organic carbon density (OCD) of the peatlands in China mostly ranges from 80 kg/m to 140 kg/m, and the range of the maximum is 270-360 kg/m, and the minimum is less than 80 kg/m. Divided by the Yanshan Mountain, Taihang Mountains and Hengduan Mountains, the peatland oganic carbon density (POCD) is lower on the northwestern side than that on the southeastern side. Jiangxi Province has the highest POCD due to the ancient buried peatlands. The OCD of the bare peatlands is mostly in the range of 60-150 kg/m, and that of the buried peatlands is more than 100 kg/m. In the bare peatlands, the OCD generally increases from the surface layer to the below surface layer, and then decreases with the depth. Although the peatlands area in China is small, the OCS per unit area is far higher than the other soil types, so peatlands protection can effectively mitigate climate change. [ABSTRACT FROM AUTHOR]

Loss‐of‐control effectiveness is a common fault in the engineering field. In the existing adaptive fault‐tolerant control algorithms, observers and Lyapunov functions are often used to estimate fault parameters. However, they can only ensure the convergence of fault parameters as time goes to infinity. This leads to the fact that the controller can only play a better fault‐tolerant role in the steady‐state process, and cannot guarantee the system performance in the transient state. Therefore, a dual fault‐tolerant control (DFTC) algorithm is proposed for a class of stochastic systems with partial loss‐of‐control effectiveness. The algorithm introduces a fault‐tolerant objective on the basis of the control objective. By establishing a new objective function, the controller is forced to have the characteristics of active learning to improve the transient performance of the fault system. An example simulation verifies the validity of DFTC. The simulation results show that DFTC can drive the system to the desired output, especially when partial loss‐of‐control efficiency occurs in the system, it can learn the unknown parameters actively, quickly, and accurately, which is significantly better than the conventional control based on the certainty equivalence principle and improves the reliability of the system. [ABSTRACT FROM AUTHOR]

[Display omitted] • A variable universe fuzzy PID control algorithm is proposed for the superheat. • The combined model of electronic expansion valve and evaporator is established. • Simulation and experimental verification are implemented. • The proposed control method has strong robustness and fast regulation. Gas engine heat pump (GEHP) is more and more widely used in various commercial buildings and residential buildings because of its advantages of high efficiency, energy saving and environmental protection. However, unstable superheat is easy to cause unstable operation of GEHP system, resulting in lower energy efficiency and unnecessary energy waste. Therefore, to achieve the reliable control of superheat, a variable universe fuzzy Proportional-Integral-Differential (PID) control method is proposed in this study. First, the combined control model of electronic expansion valve (EEV) and evaporator is established. A step response curve of superheat to the opening of EEV and the parameters of the control model are obtained by experiment. In addition, simulation of the proposed control method has been performed and compared with other two methods to evaluate the control performance. Meanwhile, the proposed control method is applied to the test bench for superheat control. The results showed that the fluctuation of superheat after reaching the steady state under the control method was kept within 0.3 °C, and the superheat could return to the steady state in a short time after being disturbed. Both simulation and experiment results indicate that the proposed control method has strong robustness and fast regulation. [ABSTRACT FROM AUTHOR]

A 2D zinc(II)-based metal–organic framework (Zn-MOF) formulated as [Zn(bimpy)(1,4-ndc)]·H2O (1, bimpy = 3,5-bis(1-imidazolyl)pyridine and 1,4-ndc = 1,4-naphthalenedicarboxylic acid) was synthesized by solvothermal reaction. Complex 1 exhibits high water and pH-independent stability. It can detect Fe3+ and ascorbic acid (AA) as a "turn-off" fluorescence probe and a "turn-on" fluorescence probe in aqueous solution with high sensitivity and selectivity, respectively. The detection limits of 1 for Fe3+ and AA are about 8.82 × 10−7 M and 6.12 × 10−7 M, respectively. The fluorescence intensity of the Fe3+@1 system can be obviously recovered after adding AA due to the reduction of Fe3+, which exhibits a fluorescence "turn-on" signal (turn-off–on) for Fe3+@1 toward AA with a low detection limit (3.53 × 10−7 M). Complex 1 still exhibits good detection of Fe3+ and AA after washing and using for five cycles. Additionally, two different multi-input molecular logic gates are established. One is used to distinguish the effect of Fe3+ and Fe2+ on the fluorescence of complex 1, and the other is to further explain the regulation of Fe3+ and AA on the fluorescence of complex 1. This work shows that complex 1 is the first MOF-based "turn-on" fluorescent probe for both Fe3+ and AA in aqueous solution. [ABSTRACT FROM AUTHOR]

A continuous peat sequence collected in the Altai Mountains, Xinjiang Province, northwestern China, provides a new opportunity to reconstruct the Holocene climate history in the arid central mountain region of Asia. Based on AMS 14 C dating, high resolution records of the humification degree and n -alkane distributions reveal that the region experienced a relatively warm and dry early Holocene (10.0–8.0 ka) and a cold and wet early mid-Holocene (8.0–6.3 ka), followed by a warm and dry mid-Holocene (6.3–5.5 ka). A shift to cold and wet conditions occurred between 5.5 and 4.0 ka, and then the climate entered into a warmer period from 4.0 to 2.5 ka. In the late Holocene (2.5–1.0 ka), the region experienced a colder and wetter climate. A gradual shift to warm and dry conditions occurred during the last 1.0 ky in this region. The regional climate patterns have been generally dominated by alternations of warm-dry and cold-wet episodes during the Holocene that were quite different from the warm-wet and cool-dry episodes in the Asian summer monsoon region. Regional comparisons indicate that the climate changes in arid central Asia have been mainly influenced by the North Atlantic Ocean sea surface temperatures (SSTs) via the westerlies. However, owing to the mountainous character of the study areas, glacial meltwater, and other local factors, the climate changes in the Altai Mountains region have not always been concordant with variations of North Atlantic Ocean SSTs. We postulate that the history of moisture balance between regional precipitation, glacier and snow meltwater, and evaporation has been modulated by air temperatures that were mainly influenced by changes in the summer insolation of the Northern Hemisphere. [ABSTRACT FROM AUTHOR]

A novel two-dimensional (2D) cadmium-based metal-organic framework [Cd 2 (HDDB)(bimpy)(NMP)(H 2 O)]·3H 2 O (1) (H 5 DDB = 3,5-di(2′,4′-dicarboxylphenyl)benozoic acid and bimpy = 3,5-bis(1-imidazolyl)pyridine) has been constructed by solvothermal method, which exhibits good water stability, pH stability and excellent photoluminescence properties. Complex 1 reveals a fluorescence turn-off behaviour towards nitrofuran/nitroimidazole antibiotics and DCN pesticide due to PET (photoinduced electron transfer) and FRET (fluorescence resonance energy transfer). Interestingly, complex 1 can be designed as an "on-off-on" fluorescence probe to detect Fe3+ ion and ascorbic acid (AA). The fluorescence of complex 1 can be quenched by Fe3+ ion to form a Fe3+@ 1 hybrid system, which can be ascribed to the FRET process and the week interaction between Fe3+ and 1. Then, after gradually adding AA into Fe3+@ 1 system, the fluorescence intensity of Fe3+@ 1 fluorescence-silent system was recovered (turn on). The possible fluorescence turn-on mechanism is the elimination of FRET process between Fe3+ and complex 1. This work represents the first example of recognition of nitrofuran/nitroimidazole antibiotics, DCN pesticide, Fe3+ ion and AA based on a MOF material in aqueous solution. A cadmium(II) metal-organic framework exhibits fluorescence turn-off behaviour for antibiotics and DCN and fluorescence on-off-on behaviour for Fe3+ and AA. Image 1 • A Cd-MOF has been synthesized with high water stability and pH stability. • Cd-MOF can detect antibiotics and DCN through fluorescence turn-off behaviour. • Cd-MOF can detect Fe3+ and ascorbic acid through fluorescence on-off-on behaviour. • Mechanisms of luminescence sensing were investigated in detail. [ABSTRACT FROM AUTHOR]