Layer-Dependent Superconductivity in Iron-Based Superconductors CsCa2Fe4As4F2 and CaKFe4As4.

In the quasi-two-dimensional superconductor NbSe2, the superconducting transition temperature (Tc) is layer-dependent, decreasing by about 60% in the monolayer limit. However, for the extremely anisotropic copper-based high-Tc superconductor Bi2Sr2CaCu2O8+δ (Bi-2212), the Tc of the monolayer is almost identical with that of its bulk counterpart. To clarify the effect of dimensionality on superconductivity, here, we successfully fabricate ultrathin flakes of iron-based high-Tc superconductors CsCa2Fe4As4F2 and CaKFe4As4. It is found that the Tc of monolayer CsCa2Fe4As4F2 (after tuning to the optimal doping by ionic liquid gating) is about 20% lower than that of the bulk crystal, while the Tc of three-layer CaKFe4As4 decreases by 46%, showing a more pronounced dimensional effect than that of CsCa2Fe4As4F2. By carefully examining their anisotropy and the c-axis coherence length, we reveal the general trend and empirical law of the layer-dependent superconductivity in these quasi-two-dimensional superconductors.

Perioperative Administration of Tranexamic Acid and Low Molecular Weight Heparin for Enhanced Blood Management in Intertrochanteric Fractures: A Randomized Controlled Study.

BACKGROUND This prospective study from a single center aimed to compare the perioperative blood loss (PBL) in 79 patients with intertrochanteric fractures (IF) treated with intramedullary nailing (IMN) using 3 regimens of combined tranexamic acid (TXA) and low molecular weight heparin (LMWH), proposing a novel therapy of 4-dose TXA. MATERIAL AND METHODS We recruited 79 patients and randomly divided them into 3 groups. The 4-dose TXA group (22 patients) received 1.0 g intravenous TXA 30 min before surgery and 1.0 g at intervals of 3, 6, and 9 h before surgery. The 1-dose TXA group (25 patients) received 1.0 g intravenous TXA 30 min before surgery, while the control group (32 patients) did not receive TXA. LMWH was applied 12 h after surgery in each group. The primary metrics evaluated included hidden blood loss (HBL), total blood loss (TBL), and the number and incidence rate of deep vein thrombosis (DVT). RESULTS Analysis of the HBL revealed that the 4-dose TXA group had the lowest average (583.13±318.08 ml), followed by the 1-dose TXA group (902.94±509.99 ml), and the control group showed the highest (1154.39±452.06 ml) (P<0.05). A similar result was observed for TBL (4-dose group: 640.86±337.22 ml, 1-dose group: 971.74±511.14 ml, control group: 1226.27±458.22 ml, P<0.05). Regarding DVT, the 4-dose TXA group had 5 cases (incidence rate 22.73%), the 1-dose TXA group had 6 cases (incidence rate 24.00%), and the control group had 8 cases (incidence rate 25.00%), with no significant difference among groups (P>0.05). CONCLUSIONS Treatment using 4-dose TXA and LMWH can effectively reduce PBL without increasing the DVT risk in IF patients with IMN.

Modulating Charge-Density Wave Order and Superconductivity from Two Alternative Stacked Monolayers in a Bulk 4Hb-TaSe2 Heterostructure via Pressure.

Two-dimensional (2D) van der Waals heterostructures (VDWHs) containing a charge-density wave (CDW) and superconductivity (SC) have revealed rich tunability in their properties, which provide a new route for optimizing their novel exotic states. The interaction between SC and CDW is critical to its properties; however, understanding this interaction within VDWHs is very limited. A comprehensive in situ study and theoretical calculation on bulk 4Hb-TaSe2 VDWHs consisting of alternately stacking 1T-TaSe2 and 1H-TaSe2 monolayers are investigated under high pressure. Surprisingly, the superconductivity competes with the intralayer and adjacent-layer CDW order in 4Hb-TaSe2, which results in substantially and continually boosted superconductivity under compression. Upon total suppression of the CDW, the superconductivity in the individual layers responds differently to the charge transfer. Our results provide an excellent method to efficiently tune the interplay between SC and CDW in VDWHs and a new avenue for designing materials with tailored properties.

Diagnostic value of ultrasonography for injury of anterior talofibular ligament and anterior inferior tibiofibular ligament distal fascicle in patients with ankle fractures. / è¶ å£°è¯„ä¼°è¸å ³èŠ‚éª¨æŠ˜æ‚£è€ è·è “å‰éŸ§å¸¦åŠä¸‹èƒ«è “å‰éŸ§å¸¦è¿œä¾§æŸæŸä¼¤çš„ä»·å€¼.

OBJECTIVES: To explore the diagnostic value of ultrasonography for injuries of anterior talofibular ligament (ATFL) and anterior inferior tibiofibular ligament distal fascicle (ATiFL-DF) in patients with ankle fractures. METHODS: Clinical data of 51 patients with ankle fractures who were clinically suspected of ligament injuries and underwent ankle ultrasonography examination and arthroscopy in Sir Run Run Shaw Hospital, Zhejiang University School of Medicine from April 2019 to March 2023 were retrospectively analyzed. Using arthroscopic findings as the gold standard, the sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of ultrasonography in diagnosing ATFL and ATiFL-DF injuries were evaluated; and Kappa consistency test was further performed. RESULTS: The sensitivity and specificity of ultrasonography in diagnosis of ATFL injury were 100.0% and 92.3%, with the PPV of 92.6% and NPV of 100.0%. Ultrasonography findings exhibited excellent concordance with arthroscopic results (kappa=0.849). The sensitivity and specificity of ultrasonography in diagnosis of ATiFL-DF injury was 86.7% and 33.3%, with the PPV of 90.7% and NPV of 25.0%. But the consistence between ultrasonography and arthroscopic results was poor (kappa=0.168). CONCLUSIONS: Ultrasonography is a reliable diagnostic modality for assessing injuries to the ATFL in patients with ankle fractures; however, its specificity is limited when evaluating injuries to the ATiFL-DF. Therefore, ankle arthroscopy is necessary for ankle fracture patients with negative findings of ATiFL-DF in ultrasonography.

Optical noise-resistant nonreciprocal phonon blockade in a spinning optomechanical resonator.

A scheme of nonreciprocal conventional phonon blockade (PB) is proposed in a spinning optomechanical resonator coupled with a two-level atom. The coherent coupling between the atom and breathing mode is mediated by the optical mode with a large detuning. Due to the Fizeau shift caused by the spinning resonator, the PB can be implemented in a nonreciprocal way. Specifically, when the spinning resonator is driven from one direction, the single-phonon (1PB) and two-phonon blockade (2PB) can be achieved by adjusting both the amplitude and frequency of the mechanical drive field, while phonon-induced tunneling (PIT) occurs when the spinning resonator is driven from the opposite direction. The PB effects are insensitive to cavity decay because of the adiabatic elimination of the optical mode, thus making the scheme more robust to the optical noise and still feasible even in a low-Q cavity. Our scheme provides a flexible method for engineering a unidirectional phonon source with external control, which is expected to be used as a chiral quantum device in quantum computing networks.

Determination of Pentachlorophenol in Seafood Samples from Zhejiang Province Using Pass-Through SPE-UPLC-MS/MS: Occurrence and Human Dietary Exposure Risk.

Pentachlorophenol (PCP) has attracted wide attention due to its high toxicity, persistence, and bioaccumulation. In this study, a sensitive UPLC-MS/MS method for the determination of PCP in seafood samples was developed and validated. The samples were ultrasonic extracted with acetonitrile containing 1% acetic acid-acetonitrile and followed by using a pass-through solid-phase extraction (SPE) cleanup on Captiva EMR-Lipid cartridges. The linearity of this method ranged from 1 to 1000 µg/L, with regression coefficients of >0.99. The detection limit and quantitation limit were 0.5 µg/kg and 1.0 µg/kg, respectively. The recoveries in different types of seafood samples ranged from 86.4% to 102.5%, and the intra-day and inter-day relative standard deviations (RSDs) were 3.7% to 11.2% and 2.9% to 12.1%, respectively (n = 6). Finally, the method has been successfully utilized for the screening of PCP in 760 seafood samples from Zhejiang Province. PCP was detected in 5.8% of all seafood samples, with the largest portion of detections found in shellfish, accounting for approximately 60% of the total. The average concentrations detected ranged from 1.08 to 21.49 µg/kg. The non-carcinogenic risk indices for adults and children who consume PCP ranged from 10-4 to 10-3 magnitudes. All of these indices stayed significantly below 1, implying that the health risk from PCP in marine organisms to humans is minimal.

Evaluation of topical methylene blue nanoemulsion for wound healing in diabetic mice.

CONTEXT: Diabetic wounds (DW) are a complication of diabetes and slow wound healing is the main manifestation. Methylene blue (MB) has been shown to exhibit therapeutic effects on diabetes-related diseases. OBJECTIVE: To investigate the mechanisms of action of MB-nanoemulsion (NE) in the treatment of DW. MATERIALS AND METHODS: The concentration of MB-NE used in the in vivo and in vitro experiments was 0.1 mg/mL. Streptozocin-induced diabetic mice were used as models. The mice were separated into nondiabetic, diabetic, MB-NE treated, and NE-treated groups. Intervention of high glucose-induced human umbilical vein endothelial cells using MB-NE. The mechanism by which MB-NE promotes DW healing is investigated by combining histological analysis, immunofluorescence analysis, TUNEL and ROS assays and western blotting. RESULTS: In diabetic mice, the MB-NE accelerated DW healing (p < 0.05), promoted the expression of endothelial cell markers (α-SMA, CD31 and VEGF) (p < 0.05), and reduced TUNEL levels. In vitro, MB accelerated the migration rate of cells (p < 0.05); promoted the expression of CD31, VEGF, anti-apoptotic protein Bcl2 (p < 0.05) and decreased the expression of the pro-apoptotic proteins cleaved caspase-3 and Bax (p < 0.05). MB upregulated the expression of Nrf2, catalase, HO-1 and SOD2 (p < 0.05). In addition, MB reduced the immunofluorescence intensity of TUNEL and ROS in cells and reduced apoptosis. The therapeutic effect of MB was attenuated after treatment with an Nrf2 inhibitor (ML385). DISCUSSION AND CONCLUSION: This study provides a foundation for the application of MB-NE in the treatment of DW.

Superconductivity in an Orbital-Reoriented SnAs Square Lattice: A Case Study of Li0.6 Sn2 As2 and NaSnAs.

Searching for functional square lattices in layered superconductor systems offers an explicit clue to modify the electron behavior and find exotic properties. The trigonal SnAs3 structural units in SnAs-based systems are relatively conformable to distortion, which provides the possibility to achieve structurally topological transformation and higher superconducting transition temperatures. In the present work, the functional As square lattice was realized and activated in Li0.6 Sn2 As2 and NaSnAs through a topotactic structural transformation of trigonal SnAs3 to square SnAs4 under pressure, resulting in a record-high Tc among all synthesized SnAs-based compounds. Meanwhile, the conductive channel transfers from the out-of-plane pz orbital to the in-plane px +py orbitals, facilitating electron hopping within the square 2D lattice and boosting the superconductivity. The reorientation of p-orbital following a directed local structure transformation provides an effective strategy to modify layered superconducting systems.

In Situ Investigations on Structural Evolutions during the Facile Synthesis of Cubic α-MoC1-x Catalysts.

Cubic α-phase molybdenum carbides (α-MoC1-x) exhibit great potential in hydrogen production at low temperatures due to their excellent activity in water dissociation. However, the design strategies of α-MoC1-x are severely restricted by the harsh synthesis conditions, which involve multistep ammonification and carburization or the utilization of a significant amount of noble metals. Herein, high-purity α-MoC1-x synthesis in a one-step carburization process was achieved with the assistance of a trace amount of Rh (0.02%). The structural evolution of Mo species during phase transition was monitored via qualitative and quantitative analysis by in situ X-ray diffraction (XRD) and in situ X-ray absorption spectroscopy (XAS), respectively. Environmental transmission electron microscopy (ETEM) was used to follow the visual changes. We reveal that the reduction of monoclinic MoO3 to cubic oxygen-deficient Mo oxide (MoOx) at low temperatures owing to the promoted H2 activation on Rh sites is vital to the following carbon atom insertion and transformation to α-MoC1-x, making the carburization follow the topological route. The systematic analysis of the relationship between the reduction behavior and the structural evolution supplies a feasible strategy for the α-MoC1-x synthesis, and in situ characterizations shed light on controlling the phase transformation during carburization.

Superatomic-Charge-Density-Wave in Cluster-Assembled Au6Te12Se8 Superconductors.

Superatomic crystals are a class of hierarchical materials composed of atomically precise clusters assembled via van der Waals or covalent-like interactions. Au6Te12Se8, an all-inorganic superatomic superconductor exhibiting superatomic-charge-density-wave (S-CDW), provides the first platform to study the response of its collective quantum phenomenon to the external pressure in superatomic crystals. We reveal a competition between S-CDW and superconductivity in an ultra-narrow pressure range. Distinct from conventional CDW ordering, S-CDW shows the lowest threshold (0.1 GPa) toward external pressure that is 1-2 orders of magnitude lower than other atomic compounds. Prominently, a second superconducting phase emerges above 7.3 GPa with a threefold enhancement in the transition temperature (Tc) to 8.5 K, indicating a switch of the conduction channel from the a- to b-axis. In situ synchrotron diffractions and theoretical calculations reveal a pressure-mediated mesoscopic slip of the superatoms and a 2D-3D transition of the Fermi surface topology, which well explains the observed dimensional crossover of conductivity and re-entrant superconductivity.

Rapid Measurement of Residual Kanamycin Using Highly Specific Biomimetic Recognition Paper-Based Chip.

The development of highly specific biomimetic recognition material is a challenge for rapid detection of harmful residues in foodstuff. In this study, a paper-based boronate affinity metal-organic framework/molecularly imprinted polymer microfluidic chip (FZS-BA@MIP) was constructed based on the in situ construction strategy, which was also designed as a highly specific biomimetic recognition module. Here, the homogeneous zeolitic imidazole framework-8 (ZIF-8) membrane served as a great scaffold and enrichment layer. Besides, the recognition layer of MIP was prepared based on a highly oriented boronate affinity surface imprinting strategy. With the aid of the liquid flow channel, the highly specific enrichment and visual detection for antibiotic residues like kanamycin in actual products were achieved on the paper chip module of an integrated lateral flow platform. The whole analysis process could be accomplished within 30 min. In brief, this study offered a new integrated biomimetic recognition platform for visually detecting harmful veterinary residues containing cis-diols, which demonstrated promising commercial value in point-of-care testing of foodborne hazardous compounds.

Molecular Dynamics Study on the Demulsification Mechanism of Water-In-Oil Emulsion with SDS Surfactant under a DC Electric Field.

Application of an electric field is an effective demulsification method for water-in-oil (W/O) emulsions. For the W/O emulsions stabilized by anionic surfactants, the microscopic demulsification mechanism is still not very clear. In this work, the coalescence behavior of two droplets stabilized by the anionic surfactant sodium dodecyl sulfate (SDS) in the oil phase under a DC electric field is investigated by molecular dynamics simulation. The effects of electric field strength and oil type on the electrocoalescence of two water droplets are mainly considered. The trajectory snapshots and center of mass of the two water droplets suggest that there is almost no migratory coalescence. The movement of sodium ions and SDS, which is a combined effect of the electric field force and the resistance from the oil phase, is crucial for the deformation and connection of two water droplets. The results of mean square displacement, radial distribution function, hydration number, and interaction energies of Na+-H2O and SDS-H2O indicate that the sodium ion has a stronger ability to carry water molecules for movement than SDS. The stronger electric field strength will result in more severe deformation and shorter coalescence time. Under the higher electric field strength, the two droplets will be elongated into a slender water ribbon. By applying a pulsed DC electric field with suitable amplitude, frequency, and duty ratio, it is possible to achieve full coalescence for the ionic surfactant-stabilized W/O emulsions. The oil phase also plays an important role for the deformation of droplets and the migration of emulsion components. For the different oil phases, a longer time or stronger electric field strength would be needed for the electrocoalescence of droplets in the oil phase with higher density and viscosity. Our results are expected to be helpful for practical application in the petroleum industry and chemical engineering.

Hemorrhagic shock after contrast-enhanced ultrasound-guided liver biopsy: A case report of primary hepatic angiosarcoma.

Primary hepatic angiosarcoma (PHA) is a rare, highly aggressive malignancy. There is no specificity in clinical manifestations, laboratory examinations and imaging examinations. The definitive diagnosis of PHA depends on pathological analysis. The gold standard method to obtain specimens is percutaneous transhepatic biopsy under the guidance of contrast-enhanced ultrasound (CEUS). However, CEUS-guided biopsy for PHA is controversial. If a biopsy is necessary, a comprehensive preoperative evaluation is essential. In addition, CEUS has an auxiliary value in diagnosing PHA. In this case, we present an elderly woman who underwent CEUS-guided liver mass biopsy. The patient developed hemorrhagic shock after biopsy.

Resveratrol accelerates wound healing by inducing M2 macrophage polarisation in diabetic mice.

CONTEXT: The reduction in M2 macrophage polarisation plays a major role during diabetic wound healing. Resveratrol (RSV) can promote the polarisation of M2 macrophages and accelerate diabetic wound healing. However, the specific mechanism by which RSV regulates M2 macrophage polarisation to promote diabetic wound healing is unclear. OBJECTIVE: This study evaluated the effectiveness of RSV on diabetic wound healing and analysed the underlying mechanisms. MATERIALS AND METHODS: STZ-induced C57/B6 mice were used as a diabetic mice model for a period of 15 days. RSV (10 µmol/L) was injected around the wound to evaluate the effect of RSV on the healing process of diabetic wounds. The human monocyte line THP-1 was used to evaluate the effects of RSV (10 µmol/L) on polarisation of M2 macrophages and the secretion of pro-inflammatory factors. RESULTS: In vivo, RSV significantly increased diabetic wound healing (p < 0.05) and make the regenerated skin structure more complete. And it promoted the expression of α-SMA and Collagen I (p < 0.05). Moreover, RSV reduced the secretion of inflammatory factors (TNF-α, iNOS and IL-1ß) (p < 0.05) and promoted M2 macrophage polarisation by increasing Arg-1 and CD206 expression (p < 0.01). In vitro, RSV promoted the polarisation of M2 macrophages (p < 0.001) and reduced the secretion of pro-inflammatory factors (TNF-α, IL-6 and IL-1ß) (p < 0.05). The therapeutic effects of RSV were all significantly reversed with LY294002 (p < 0.01). DISCUSSION AND CONCLUSIONS: RSV has the positive effects on promoting the acceleration and quality of skin wound healing, which provides a scientific basis for clinical treatment in diabetic wound.

Straw retention efficiently improves fungal communities and functions in the fallow ecosystem.

BACKGROUND: Straw retention is a substitute for chemical fertilizers, which effectively maintain organic matter and improve microbial communities on agricultural land. The purpose of this study was to provide sufficient information on soil fungal community networks and their functions in response to straw retention. Hence, we used quantitative real-time PCR (qRT-PCR), Illumina MiSeq (ITS rRNA) and FUNGuild to examine ITS rRNA gene populations, soil fungal succession and their functions under control (CK) and sugarcane straw retention (SR) treatments at different soil layers (0-10, 10-20, 20-30, and 30-40 cm) in fallow fields. RESULT: The result showed that SR significantly enhanced ITS rRNA gene copy number and Shannon index at 0-10 cm soil depth. Fungi abundance, OTUs number and ACE index decreased with the increasing soil depth. The ANOSIM analysis revealed that the fungal community of SR significantly differed from that of CK. Similarly, significant difference was also observed between topsoil (0-20 cm) and subsoil (20-40 cm). Compared with CK, SR decreased the relative abundance of the pathogen, while increased the proportion of saprotroph. Regarding soil depth, pathogen relative abundance in topsoil was lower than that in subsoil. Besides, both sugarcane straw retention and soil depths (topsoil and subsoil) significantly altered the co-occurrence patterns and fungal keystone taxa closely related to straw decomposition. Furthermore, both SR and topsoil had higher average clustering coefficients (aveCC), negative edges and varied modularity. CONCLUSIONS: Overall, straw retention improved α-diversity, network structure and fungal community, while reduced soil pathogenic microbes across the entire soil profile. Thus, retaining straw to improve fungal composition, community stability and their functions, in addition to reducing soil-borne pathogens, can be an essential agronomic practice in developing a sustainable agricultural system.

Determination of a six-gene prognostic model for cervical cancer based on WGCNA combined with LASSO and Cox-PH analysis.

AIM: This study aimed to establish a risk model of hub genes to evaluate the prognosis of patients with cervical cancer. METHODS: Based on TCGA and GTEx databases, the differentially expressed genes (DEGs) were screened and then analyzed using GO and KEGG analyses. The weighted gene co-expression network (WGCNA) was then used to perform modular analysis of DEGs. Univariate Cox regression analysis combined with LASSO and Cox-pH was used to select the prognostic genes. Then, multivariate Cox regression analysis was used to screen the hub genes. The risk model was established based on hub genes and evaluated by risk curve, survival state, Kaplan-Meier curve, and receiver operating characteristic (ROC) curve. RESULTS: We screened 1265 DEGs between cervical cancer and normal samples, of which 620 were downregulated and 645 were upregulated. GO and KEGG analyses revealed that most of the upregulated genes were related to the metastasis of cancer cells, while the downregulated genes mostly acted on the cell cycle. Then, WGCNA mined six modules (red, blue, green, brown, yellow, and gray), and the brown module with the most DEGs and related to multiple cancers was selected for the follow-up study. Eight genes were identified by univariate Cox regression analysis combined with the LASSO Cox-pH model. Then, six hub genes (SLC25A5, ENO1, ANLN, RIBC2, PTTG1, and MCM5) were screened by multivariate Cox regression analysis, and SLC25A5, ANLN, RIBC2, and PTTG1 could be used as independent prognostic factors. Finally, we determined that the risk model established by the six hub genes was effective and stable. CONCLUSIONS: This study supplies the prognostic value of the risk model and the new promising targets for the cervical cancer treatment, and their biological functions need to be further explored.

Transitions from a Kondo-like diamagnetic insulator into a modulated ferromagnetic metal in FeGa3-yGey.

One initial and essential question of magnetism is whether the magnetic properties of a material are governed by localized moments or itinerant electrons. Here, we expose the case for the weakly ferromagnetic system FeGa3-y Ge y , wherein these two opposite models are reconciled, such that the magnetic susceptibility is quantitatively explained by taking into account the effects of spin-spin correlation. With the electron doping introduced by Ge substitution, the diamagnetic insulating parent compound FeGa3 becomes a paramagnetic metal as early as at y=0.01, and turns into a weakly ferromagnetic metal around the quantum critical point y=0.15. Within the ferromagnetic regime of FeGa3-y Ge y , the magnetic properties are of a weakly itinerant ferromagnetic nature, located in the intermediate regime between the localized and the itinerant dominance. Our analysis implies a potential universality for all itinerant-electron ferromagnets.

Nontrivial superconductivity in topological MoTe2-x S x crystals.

Topological Weyl semimetals (TWSs) with pairs of Weyl points and topologically protected Fermi arc states have broadened the classification of topological phases and provide superior platform for study of topological superconductivity. Here we report the nontrivial superconductivity and topological features of sulfur-doped Td -phase MoTe2 with enhanced Tc compared with type-II TWS MoTe2 It is found that Td -phase S-doped MoTe2 (MoTe2-x S x , x ∼ 0.2) is a two-band s-wave bulk superconductor (∼0.13 meV and 0.26 meV), where the superconducting behavior can be explained by the s+- pairing model. Further, measurements of the quasi-particle interference (QPI) patterns and a comparison with band-structure calculations reveal the existence of Fermi arcs in MoTe2-x S x More interestingly, a relatively large superconducting gap (∼1.7 meV) is detected by scanning tunneling spectroscopy on the sample surface, showing a hint of topological nontrivial superconductivity based on the pairing of Fermi arc surface states. Our work demonstrates that the Td -phase MoTe2-x S x is not only a promising topological superconductor candidate but also a unique material for study of s+- superconductivity.

A Novel Noise Reduction Method of UAV Magnetic Survey Data Based on CEEMDAN, Permutation Entropy, Correlation Coefficient and Wavelet Threshold Denoising.

Despite the increased attention that has been given to the unmanned aerial vehicle (UAV)-based magnetic survey systems in the past decade, the processing of UAV magnetic data is still a tough task. In this paper, we propose a novel noise reduction method of UAV magnetic data based on complete ensemble empirical mode decomposition with adaptive noise (CEEMDAN), permutation entropy (PE), correlation coefficient and wavelet threshold denoising. The original signal is first decomposed into several intrinsic mode functions (IMFs) by CEEMDAN, and the PE of each IMF is calculated. Second, IMFs are divided into four categories according to the quartiles of PE, namely, noise IMFs, noise-dominant IMFs, signal-dominant IMFs, and signal IMFs. Then the noise IMFs are removed, and correlation coefficients are used to identify the real signal-dominant IMFs. Finally, the wavelet threshold denoising is applied to the real signal-dominant IMFs, the denoised signal can be obtained by combining the signal IMFs and the denoised IMFs. Both synthetic and field experiments are conducted to verify the effectiveness of the proposed method. The results show that the proposed method can eliminate the interference to a great extent, which lays a foundation for the further interpretation of UAV magnetic data.

Development of a mesoporous silica based solid-phase extraction and ultra-performance liquid chromatography-MS/MS method for quantifying lignans in Justicia procumbens.

Justicia procumbens is a food and medicine homologous variety, popularly used for making vegetable soups. In this study, a novel mesoporous silica was synthesized and used as the sorbent of SPE for the purification of lignans from J. procumbens. A laboratory-made SPE cartridge was packed with 100 mg of mesoporous silica, which was washed with 10% methanol and eluted using 0.8 mL acetonitrile after sample loading. Afterward, the extract was analyzed by ultra-performance liquid chromatography (UPLC) and MS/MS. All the lignans were efficiently separated in 6 min with the noise level in the range of 50-150 cps. 6'-Hydroxy justicidin B, 6'-hydroxy justicidin A, justicidin B, chinensinaphthol methyl ether, justicidin C, and neojusticdin A were identified to be the dominant molecular species in J. procumbens with contents of 0.065-0.37 mg/g in three tested sample batches from different geographic origins. In conclusion, the proposed mesoporous silica based SPE UPLC-MS/MS method is efficient in linearity (R2 = 0.9989-0.9996), sensitivity (LOD ≤0.13 µg/kg and LOQ ≤0.42 µg/kg), precision (RSDintra-day ≤3.12 and RSDinter-day ≤4.56), and recovery (83.42-96.11%, RSD ≤2.88%).