Time-Frequency Aliased Signal Identification Based on Multimodal Feature Fusion.

The identification of multi-source signals with time-frequency aliasing is a complex problem in wideband signal reception. The traditional method of first separation and identification especially fails due to the significant separation error under underdetermined conditions when the degree of time-frequency aliasing is high. The single-mode recognition method does not need to be separated first. However, the single-mode features contain less signal information, making it challenging to identify time-frequency aliasing signals accurately. To solve the above problems, this article proposes a time-frequency aliasing signal recognition method based on multi-mode fusion (TRMM). This method uses the U-Net network to extract pixel-by-pixel features of the time-frequency and wave-frequency images and then performs weighted fusion. The multimodal feature scores are used as the classification basis to realize the recognition of the time-frequency aliasing signals. When the SNR is 0 dB, the recognition rate of the four-signal aliasing model can reach more than 97.3%.

Pharmacokinetics, withdrawal period and risk assessment of enrofloxacin in the northern snakehead (Channa argus) following bath administration.

Enrofloxacin (ENR) is widely used in aquaculture practice, but little is known about its pharmacokinetic, withdrawal period and dietary risk in fish via bath administration. The purpose of this study was to provide data support for the use of ENR bath therapy in the northern snakehead (Channa argus). The pilot study was carried out to evaluate the therapy concentrations of ENR in northern snakehead with immersion concentrations ranged from 5 to 40 mg/L for 6 h. Based on results of the pilot study, an ENR immersion concentration of 20 mg/L was used for the formal experiment. At this dose, the peak concentrations of ENR in plasma, muscle plus skin, liver and kidney were 4.85, 4.55, 3.87 and 7.42 µg/mL (or g), respectively. According to the AUC0-∞ values, the distribution of ENR in northern snakehead followed the order of kidney > plasma > liver > muscle + skin. The elimination of ENR in northern snakehead was very slow, the half-lives (T1/2λz ) were up to 90.31, 85.5, 104.56 and 120.9 h in plasma, muscle plus skin, liver and kidney, respectively. Ciprofloxacin (CIP) was not detected in any samples in the pilot study and was only occasionally detected in muscle plus skin and liver samples in formal experiment. Based on the calculated PK/PD index AUC/MIC and Cmax /MIC, the current bath treatment regimen will have a good therapeutic effect on infections caused by bacteria with MIC below 0.6 µg/mL. The dietary risk assessment suggested that there was a dietary risk (Hazard Quotients > 10%) until day 6 after bath treatment. It is mandatory for ENR to maintain a withdrawal period of at least 450°C-day in northern snakehead after bath treatment ceased.

Notoginsenoside R1 inhibits hepatitis B virus replication by modulating SIRT1 activity.

The hepatitis B virus (HBV) infection remains highly prevalent globally. The present study aimed to explore the possible therapeutic effect of notoginsenoside R1, which has attracted considerable attention due to its diverse pharmacological effects, on HBV infection. The HBV-containing hepatocellular carcinoma cell lines, HepG2 and MHCC97H, were used in this study. We first treated the two cell lines with different concentrations of notoginsenoside R1 and subsequently measured the relative levels of HBV DNA, HBV surface antigen, HBV core antigen, and sirtuin 1 (SIRT1) using reverse transcription-quantitative polymerase chain reaction and western blotting. Finally, an HBV hemodynamic replication model was created to test the effect of notoginsenoside R1 on HBV replication. Notoginsenoside R1 inhibited the replication of HBV. This inhibitory effect was mediated through the downregulation of SIRT1 activity. Additionally, the inhibition of SIRT1 activity by silencing its expression or treatment with the SIRT1 inhibitor, selisistat, suppressed HBV replication. Furthermore, our animal experiments demonstrated that notoginsenoside R1 was effective at suppressing HBV replication in vivo. Thus, notoginsenoside R1 suppresses HBV replication by downregulating SIRT1 activity in vitro and in vivo. Keywords: notoginsenoside R1; hepatitis B virus; SIRT1.

Investigation on the co-combustion characteristics of multiple biomass and coal under O2/CO2 condition and the interaction between different biomass.

The co-combustion of coal and biomass in O2/CO2 conditions is a promising technology for CO2 capture and waste disposal. Little attention has been paid to the interaction between different biomass in co-combustion process, which is of great significance to the study of the co-combustion mechanism. The co-combustion behavior of coal and multiple biomass under isothermal conditions was characterized by thermogravimetric method, and the interaction between different biomass was investigated from the perspective of thermogravimetric and proximate analysis. It found that biomass blending could remarkably improve the combustion performance of coal. Compared to the theoretical prediction, the interaction between coal and biomass showed remarkably promoting effects when the coal was blended with different biomass. While the interaction between different biomass was weak. Moreover, the influence of proximate analysis on combustion characteristic parameters was studied by establishing the linear relationship between combustion characteristic parameters and proximate analysis. The effects of proximate analysis on characteristic time/S were divided into five categories, and it were mainly controlled by the interaction both between coal with biomass and between different biomass.

The toxicokinetics and risk assessment of pyrethroids pesticide in tilapia (Oreochromis mossambicus) upon short-term water exposure.

Pyrethroids pesticides (PPs) are the widely adopted synthetic pesticides for agriculture and fishery. The frequent use of these pesticides leads to the accumulation of residues in the freshwater environments in China, subsequently affecting aquatic organisms and ecosystems. However, there are few reports on the toxicological and risk assessment of aquaculture aquatic products. In this study, the uptake, depuration kinetics and potential risk to human health and ecology of fenpropathrin, cypermethrin, fenvalerate, and deltamethrin were assessed using tilapia. The results indicated that four PPs were readily accumulated by tilapia. The bioconcentration factors (BCF) of the PPs in plasma and muscle were between 71.3 and 2112.1 L/kg and 23.9-295.3 L/kg, respectively. The half-lives (t1/2) of muscle and plasma were 2.90-9.20 d and 2.57-8.15 d. The risks of PPs residues in the muscle of tilapia and exposed water were evaluated by hazard quotient (HQ) and risk quotient (RQ). Although PPs residues in tilapia had a low dietary risk to human health, the residues in the exposed water had a high ecological risk to fish, daphnia, and green algae. Therefore, assessing the PPs content in freshwater aquaculture and monitoring their dosages and frequencies are highly necessitated to avoid their adverse effect on the aquaculture environment.

Mechanism of One-Step Hydrothermally Synthesized Titanate Catalysts for Ozonation.

A titanate nanotube catalyst for ozonation was synthesized with a simple one-step NaOH hydrothermal treatment without energy-consuming calcination. The synthesized titania catalysts were characterized by X-ray diffraction (XRD), Raman, porosimetry analysis, high-resolution transmission electron microscopy (HR-TEM), Fourier transformed infrared (FTIR), and electron paramagnetic resonance (EPR) analysis. The catalyst treated with a higher concentration of NaOH was found to be more catalytically active for phenol removal due to its higher titanate content that would facilitate more OH groups on its surface. Furthermore, the main active oxidizing species of the catalytic ozonation process were recognized as singlet oxygen and superoxide radical, while the hydroxyl radical may only play a minor role. This work provides further support for the correlation between the properties of titania and catalytic performance, which is significant for understanding the mechanism of catalytic ozonation with titania-based materials.

Preclinical Profile and Characterization of the Hepatitis B Virus Core Protein Inhibitor ABI-H0731.

ABI-H0731, a first-generation hepatitis B virus (HBV) core protein inhibitor, has demonstrated effective antiviral activity in chronic hepatitis B (CHB) patients in a phase 1b clinical trial and is currently being further evaluated in phase 2 clinical trials. Here, we report the preclinical profile of ABI-H0731. In in vitro cell culture systems (HepG2-derived cell lines HepAD38 and HepG2-NTCP and primary human hepatocytes [PHHs]), ABI-H0731 exhibited selective inhibition of HBV DNA replication (50% effective concentration [EC50] from 173 nM to 307 nM). Most importantly, ABI-H0731 suppressed covalently closed circular DNA (cccDNA) formation in two de novo infection models with EC50s from 1.84 µM to 7.3 µM. Mechanism-of-action studies indicated that ABI-H0731 is a direct-acting antiviral that targets HBV core protein, preventing HBV pregenomic RNA (pgRNA) encapsidation and subsequent DNA replication. The combination of ABI-H0731 with entecavir appears to decrease viral DNA faster and deeper than nucleoside/nucleotide analogue (NrtI) therapy alone. In addition, ABI-H0731 disrupts incoming nucleocapsids, causing the premature release of relaxed circular DNA (rcDNA) before delivery to the nucleus, and thus prevents new cccDNA formation. ABI-H0731 exhibits pangenotypic activity and is additive to moderately synergistic when combined with an NrtI. In addition to its potency and novel mechanism of action, ABI-H0731 possesses drug-like properties and a preclinical pharmacokinetic profile supportive of once-daily dosing in patients with CHB. Taken together, these data support the ongoing clinical development of ABI-H0731 as a treatment for HBV.

Pharmacokinetics and tissue residues of enrofloxacin in the largemouth bass (Micropterus salmoides) after oral administration.

The study was carried out to evaluate the pharmacokinetic disposition of enrofloxacin (ENF) with a single dose of 20 mg/kg after oral administration in largemouth bass (Micropterus salmoides) at 28°C. The concentrations of ENF and of its metabolite ciprofloxacin (CIP) in plasma, liver, and muscle plus skin in natural proportions were determined using HPLC. The concentration-time data for ENF in plasma were best described by a two-compartment open model. After oral administration, the maximum ENF concentration (Cmax ) of 10.99 µg/ml was obtained at 0.60 hr. The absorption half-life (T1/2Ka ) of ENF was calculated to be 0.07 hr whereas the elimination half-life (T1/2ß ) of the drug was 90.79 hr. The estimates of area under the plasma concentration-time curve (AUC) and apparent volume of distribution (Vd/F) were 1,185.73 µg hr/ml and 2.21 L/kg, respectively. ENF residues were slowly depleted from the liver and muscle plus skin of largemouth bass with the T1/2ß of 124.73 and 115.14 hr, respectively. Very low levels of ciprofloxacin were detected in the plasma and tissues. A withdrawal time of 24 days was necessary to ensure that the residues of ENF + CIP in muscle plus skin were less than the maximal residue limit (MRL) of 100 µg/kg established by the European Union.

Molecular and computational analysis of 45 samples with a serologic weak D phenotype detected among 132,479 blood donors in northeast China.

BACKGROUND: RH1 is one of the most clinically important blood group antigens in the field of transfusion and in the prevention of fetal incompatibility. The molecular analysis and characterization of serologic weak D phenotypes is essential to ensuring transfusion safety. METHODS: Blood samples from a northeastern Chinese population were randomly screened for a serologic weak D phenotype. The nucleotide sequences of all 10 exons, adjacent flanking intronic regions, and partial 5' and 3' untranslated regions (UTRs) were detected for RHD genes. Predicted deleterious structural changes in missense mutations of serologicl weak D phenotypes were analyzed using SIFT, PROVEAN and PolyPhen2 software. The protein structure of serologic weak D phenotypes was predicted using Swiss-PdbViewer 4.0.1. RESULTS: A serologic weak D phenotype was found in 45 individuals (0.03%) among 132,479 blood donors. Seventeen distinct RHD mutation alleles were detected, with 11 weak D, four partial D and two DEL alleles. Further analyses resulted in the identification of two novel alleles (RHD weak D 1102A and 399C). The prediction of a three-dimensional structure showed that the protein conformation was disrupted in 16 serologic weak D phenotypes. CONCLUSIONS: Two novel and 15 rare RHD alleles were identified. Weak D type 15, DVI Type 3, and RHD1227A were the most prevalent D variant alleles in a northeastern Chinese population. Although the frequencies of the D variant alleles presented herein were low, their phenotypic and genotypic descriptions add to the repertoire of reported RHD alleles. Bioinformatics analysis on RhD protein can give us more interpretation of missense variants of RHD gene.

Use of a Fluorescent Analogue of a HBV Core Protein-Directed Drug To Interrogate an Antiviral Mechanism.

Heteroaryldihydropyrimidines (HAPs) are antiviral small molecules that enhance assembly of HBV core protein (Cp), lead to assembly of empty and defective particles, and suppress viral replication. These core protein allosteric modulators (CpAMs) bind to the pocket at the interface between two Cp dimers and strengthen interdimer interactions. To investigate the CpAM mechanism, we wanted to examine the cellular distributions of Cp and the CpAM itself. For this reason, we developed a fluorescently labeled CpAM, HAP-ALEX. In vitro, HAP-ALEX modulated assembly of purified Cp and at saturating concentrations induced formation of large structures. HAP-ALEX bound capsids and not dimers, making it a capsid-specific molecular tag. HAP-ALEX labeled HBV in transfected cells, with no detectable background with a HAP-insensitive Cp mutant. HAP-ALEX caused redistribution of Cp in a dose-dependent manner consistent with its 0.7 µM EC50, leading to formation of large puncta and an exclusively cytoplasmic distribution. HAP-ALEX colocalized with the redistributed Cp, but large puncta accumulated long before they appeared saturated with the fluorescent CpAM. CpAMs affect HBV assembly and localization; with a fluorescent CpAM both drug and target can be identified.

Insights into the Chemical Mechanism for CO2(aq) and H+ in Aqueous Diamine Solutions - An Experimental Stopped-Flow Kinetic and 1H/13C NMR Study of Aqueous Solutions of N,N-Dimethylethylenediamine for Postcombustion CO2 Capture.

In an effort to advance the understanding of multiamine based CO2 capture process absorbents, we report here the determination of the kinetic and equilibrium constants for a simple linear diamine N,N-dimethylethylenediamine (DMEDA) via stopped-flow spectrophotometric kinetic measurements and 1H/13C NMR titrations at 25.0 °C. From the kinetic data, the formation of monocarbamic acid (DMEDACOOH) from the reaction of DMEDA with CO2(aq) is the dominant reaction at high pH > 9.0 (k7 = 6.99 × 103 M-1·s-1). Below this pH, the formation of protonated monocarbamic acid (DMEDACOOH2) via the pathway involving DMEDAH+ and CO2(aq) becomes active and contributes to the kinetics despite the 107-fold decrease in the rate constant between the two pathways. 1H and 13C NMR spectra as a function of decreasing pH (increasing HCl concentration) at 25.0 °C have been evaluated here to confirm the protonation events in DMEDA. Calculations of the respective DMEDA nitrogen partial charges have also been undertaken to support the NMR protonation study. A comparison of the DMEDA kinetic constants with the corresponding data for piperazine (PZ) reveals that despite the larger basicity of DMEDA, the enhanced and superior kinetic performance of PZ with CO2(aq) above its predicted Bronsted reactivity is not observed in DMEDA.

A Volume Measurement Method for Lunar Soil Collection Based on a Single Monitoring Camera.

In the task of lunar soil collection, estimating the volume of the collected soil is an important part of the sampling control of the lander. Due to the design constraints of the lander, there is no additional installation position for volume measurement equipment. To fully use the sensors already installed, a collected soil volume measurement method is designed in this paper based only on a single monitoring camera. This method uses a sequence of images of the collection area captured by the camera mounted on the acquisition arm to accurately reconstruct the terrain of the collection area surface before and after soil acquisition. Additionally, bi-temporal dense point clouds are reconstructed. Based on the area of change associated with soil collection, the constructed dense point clouds are compared according to the topographic characteristics of the area to estimate the volume of soil collected. Experiments show that the method is stable and reliable and can meet the requirements of actual measurement tasks.

Pharmacokinetic/pharmacodynamic relationship of enrofloxacin against Aeromonas hydrophila in crucian carp (Carassius auratus gibelio).

The pharmacokinetic (PK) properties of enrofloxacin (ENR) and its metabolite ciprofloxacin (CIP) were investigated in crucian carp following oral administration at different dose levels (5, 10, 20, 40 mg/kg body weight). The disposition kinetics of ENR was found to be linear over the dose range studied. Serum half-lives ranged from 64.56 to 72.68 hr. The in vitro and ex vivo activities of ENR in serum against a pathogenic strain of Aeromonas hydrophila were determined. In vitro and ex vivo bactericidal activity of ENR was concentration dependent. Dosing of 10 mg/kg resulted in an AUC/minimum inhibitory concentration (MIC) ratio of 368.92 hr and a Cmax /MIC ratio of 7.23, respectively, against A. hydrophila 147 (MIC = 0.48 µg/ml), indicating a likely high level of effectiveness in clinical infections caused by A. hydrophila with MIC value ≤ 0.48 µg/ml. Modeling of ex vivo growth inhibition data to the sigmoid Emax equation provided the values of AUC24 hr /MIC required to produce bacteriostasis, bactericidal activity, and elimination of bacteria, these values were 21.70, 53.01, and 125.21 hr, respectively. These findings in conjunction with MIC90 data suggested that ENR at the dose of 7.81 mg/kg predicted a positive clinical outcome and minimize the risk of emergence of resistance.

Impacts of intensive smooth cordgrass removal on net ecosystem exchange in a saltmarsh-mangrove ecotone of Southeast China.

Net ecosystem exchange (NEE) of carbon dioxide (CO2) in disturbed tidal wetlands remain less investigated, albeit the importance of these 'blue carbon' ecosystems in mitigating climate change has been increasingly recognized. The invasion of smooth cordgrass into China's unvegetated tidal wetlands promotes the carbon sink, however little is known about the changes in NEE when the cordgrass is intensively removed. Here, two-year continuous eddy covariance measurements from Nov. 2021 to Oct. 2023 were used to examine how intensive cordgrass removal affects NEE in a cordgrass-dominated saltmarsh-mangrove ecotone of Southeast China. The results showed (a) this wetland acted as a monthly CO2 sink throughout the pre-removal year with nearly 90 % of the annual sink (-719.7 g C m-2 yr-1) in the cordgrass growing season from Apr. to Oct.; (b) the cordgrass removal turned this high-sink wetland into a weak CO2 source at an annual scale (39.0 g C m-2 yr-1), while the change of the sink was diurnally and seasonally unequal with daytime and growing season, respectively, accounting for the majority of the reduction; (c) tidal inundation exerted inhibitive effects on the response of daytime and nighttime NEE to photosynthetically active radiation and air temperature, respectively, with the changes in all-day NEE more driven by photosynthesis than ecosystem respiration. As one of the first assessments on the impacts of cordgrass removal on NEE, this study confirms the reduction in annual CO2 sink is predominantly attributed to the cordgrass removal instead of the climatic difference. This study highlights the importance of the interactive effects among phenological, meteorological, and tidal factors in regulating the seasonality of NEE and its changes along with cordgrass removal. Future longer flux measurements with extended years are needed to complement the present assessment of the cordgrass removal-induced impacts on NEE from a long-term perspective.

Lunar rock investigation and tri-aspect characterization of lunar farside regolith by a digital twin.

Yutu-2 rover conducted an exciting expedition on the 41st lunar day to investigate a fin-shaped rock at Longji site (45.44°S, 177.56°E) by extending its locomotion margin on perilous peaks. The varied locomotion encountered, especially multi-form wheel slippage, during the journey to the target rock, established unique conditions for a fin-grained lunar regolith analysis regarding bearing, shear and lateral properties based on terramechanics. Here, we show a tri-aspect characterization of lunar regolith and infer the rock's origin using a digital twin. We estimate internal friction angle within 21.5°-42.0° and associated cohesion of 520-3154 Pa in the Chang'E-4 operational site. These findings suggest shear characteristics similar to Apollo 12 mission samples but notably higher cohesion compared to regolith investigated on most nearside lunar missions. We estimate external friction angle in lateral properties to be within 8.3°-16.5°, which fills the gaps of the lateral property estimation of the lunar farside regolith and serves as a foundational parameter for subsequent engineering verifications. Our in-situ spectral investigations of the target rock unveil its composition of iron/magnesium-rich low-calcium pyroxene, linking it to the Zhinyu crater (45.34°S, 176.15°E) ejecta. Our results indicate that the combination of in-situ measurements with robotics technology in planetary exploration reveal the possibility of additional source regions contributing to the local materials at the Chang'E-4 site, implying a more complicated geological history in the vicinity.

Phase diagrams map the properties of antiviral agents directed against hepatitis B virus core assembly.

Assembly effectors are small molecules that induce inappropriate virus capsid assembly to antiviral effect. To identify attributes of hepatitis B virus (HBV) assembly effectors, assembly reaction products (normal capsid, noncapsid polymer, intermediates, and free dimeric core protein) were quantified in the presence of three experimental effectors: HAP12, HAP13, and AT-130. Effectors bound stoichiometrically to capsid protein polymers, but not free protein. Thermodynamic and kinetic effects, not aberrant assembly, correlate with maximal antiviral activity.

Inhibition of lipopolysaccharide-induced iNOS and COX-2 expression by indole alkaloid, 3-(hydroxymethyl)-6,7-dihydroindolo[2,3-a]quinolizin-(12H)-one, via NF-κB inactivation in RAW 264.7 macrophages.

3-(Hydroxymethyl)-6,7-dihydroindolo[2,3-a]quinolizin-(12H)-one is a bioactive indole alkaloid isolated from Nauclea officinalis, a plant species which is used as a traditional Chinese medicine. We investigated the anti-inflammatory properties of 3-(hydroxymethyl)-6,7-dihydroindolo[2,3-a]quinolizin-(12H)-one in RAW 264.7 murine macrophages. The results indicated that it inhibited the overproduction of NO and the release of TNF-α. Furthermore, this compound inhibited the expression of iNOS and COX-2 proteins, the enzymatic activity of iNOS, and the translocation of NF-κB to the nucleus induced by LPS. Therefore, we suggested that the effect of 3-(hydroxymethyl)-6,7-dihydroindolo[2,3-a]quinolizin-(12H)-one-mediated inhibition of the expression of LPS-induced iNOS and COX-2 genes is due to the suppression of NF-κB activation in the transcriptional level.

Larvicidal activity of lansiumamide B from the seeds of Clausena lansium against Aedes albopictus (Diptera: Culicidae).

The larvicidal activity of crude petroleum ether, toluene, n-butanol, ethyl acetate, acetone, and methanol extracts of the seeds of Clausena lansium was assayed for their toxicities against the early fourth instar larvae of Aedes albopictus. The larval mortality was observed after 24-h exposure. The LC(50) value of petroleum ether extract was 22.99 ppm, showing the best larvicidal activity among all six solvent extracts. A cinnamon amide compound lansiumamide B (N-methyl-N-cis-styrylcinnamamide) was isolated from the petroleum ether extract by column chromatographic method, which exhibited a strong larvicidal activity against the early fourth instar larvae of A. albopictus with LC(50) and LC(90) values of 0.45 and 2.19 ppm, respectively. The structure was elucidated by (1)H NMR, (13)C NMR spectral data. The larvicidal activity against mosquito of lansiumamide B from the seed of C. lansium was evaluated for the first time.