Standard Curve Research Articles

The genomic copy number determination of improved Cre in transgenic mice using standards derived from megaprimer PCR constructed tandem repeats

Determination of the genomic copy number of Cre transgene is critical for the establishment of transgenic animal models. We demonstrate a real-time quantitative polymerase chain reaction (RT-qPCR) based method for genomic copy number determination of improved Cre (iCre), which was tested in a transgenic mouse model of CYP19A1-iCre. The standards were derived from tandem repeats of iCre fragments which were constructed by a new application of megaprimer PCR. Two rounds of megaprimer PCR were used to obtain specific tandem repeats of iCre fragments, which were subsequently cloned into pUCm-T vectors. After the fragments of IL-2 (reference gene) were ligated into the same vectors, standards with copy number ratios (CNR) of 0.5, 1, 2, 4, 8, and 16 between iCre and IL-2 were completed. The R2 values of the standard curves exceeded 0.99. The calculated CNR value of the quality control sample was satisfactory. Multiple copies of iCre were detected in founder mice. After several passages, the copy number of iCre gradually decreased to a single copy, which was consistent with theoretical expectation. The established method is a universal and sensitive program for genomic copy number determination of iCre in transgenic mice.

Prognostic value of Geriatric Nutritional Risk Index and systemic immune-inflammatory index in elderly patients with acute coronary syndromes

The objective of this study was to evaluate the predictive value of the Geriatric Nutritional Risk Index (GNRI) combined with the Systemic Immunoinflammatory Index (SII) for the risk of major adverse cardiovascular events (MACE) following percutaneous coronary intervention in elderly patients with acute coronary syndrome (ACS). We retrospectively reviewed the medical records of 1202 elderly patients with acute coronary syndromes divided into MACE and non-MACE groups according to whether they had a MACE. The sensitivity analysis utilized advanced machine learning algorithms to preliminarily identify the critical role of GNRI versus SII in predicting MACE risk. We conducted a detailed analysis using a restricted cubic spline approach to investigate the nonlinear relationship between GNRI, SII, and MACE risk further. We constructed a clinical prediction model based on three key factors: GNRI, SII, and Age. To validate the accuracy and usefulness of this model, we compared it to the widely used GRACE score using subject work and recall curves. Additionally, we compared the predictive value of models and GRACE scores in assessing the risk of MACE using the Integrated Discriminant Improvement Index (IDI) and the Net Reclassification Index (NRI). This study included 827 patients. The GNRI scores were lower in the MACE group than in the non-MACE group, while the SII scores were higher in the MACE group (P < 0.001). The multifactorial analysis revealed a low GNRI (OR = 2.863, 95% CI: 2.026–4.047, P = 0.001), High SII (OR = 3.102, 95% CI: 2.213–4.348, P = 0.001). The area under the curve (AUC) for the predictive model was 0.778 (95% CI: 0.744–0.813, P = 0.001), while the AUC for the GRACE score was 0.744 (95% CI: 0.708–0.779, P = 0.001). NRI was calculated to be 0.5569, with NRI + at 0.1860 and NRI- at 0.3708. The IDI was found to be 0.0571, with a P-value of less than 0.001. These results suggest that the newly developed prediction model is more suitable for use with the population in this study than the GRACE score. The model constructed using GNRI and SII demonstrated good standardization and clinical impact, as evidenced by the standard, DCA, and clinical impact curves. The study shows that combining GNRI and SII can be a simple, cost-effective, and valuable way to predict the risk of MACE within one year in elderly acute coronary syndromes.

Simple Determination of Bosentan in Plasma Samples by Reversed-Phase High-Performance Liquid Chromatography.

In order to measure the plasma levels of Losartan and Bosentan, a sensitive Reverse Phase-High Performance Liquid Chromatography (RP-HPLC) technique was developed. To compare bioavailability, the Area Under the Curve (AUC), peak plasma concentration (Cmax), and time to Cmax (Tmax) were employed. The standard curve (150-2400 ng/ml) was linear (R2=0.999), relative errors were between 2.4 to 10.05% and the coefficient of variation (CV%) ranged from 1.52 to 10.88. A single dosage (test and reference) was used for the in vivo investigation, which involved 16 healthy individuals. The AUC0-48, AUC0-, Cmax, and Tmax of the test and reference had no statistically significant differences. The Cmax and 95% confidence intervals of the ratio of Cmax of the two formulations were 0.93-0.96 and 97.6-135%, respectively. Therefore, it was established that generic Bosentan was equivalent to Bosentan from Actelion and that both medications could be regarded as equally effective in clinical settings. The blood level of Bosentan could be measured using this straightforward procedure in all hospital laboratories.

Selective Sampling to and Desorption from Single Solid-Phase Microextraction Arrow Fiber for Replicative and Quantitative Analysis.

New analytical functionality is demonstrated with an enclosed interface that joins a solid phase microextraction (SPME) device, a direct analysis in real time (DART) probe, and a high-resolution mass spectrometer. With a single 20 mm long SPME Arrow, the interface is able to perform five discrete DART analyses on different areas of the same fiber in 1 min of practical operation time. Three-fiber replicates for 15 runs total produce 15% or better center of variance (CV) values for both volatile headspace sampling and direct immersion sampling of a solvated analyte. Chemometric analysis of rapidly acquired headspace data is able to distinguish volatile profiles. Selective desorption within the interface also confers the ability to selectively sample to discrete areas of a fiber, and three different headspace samples or five different liquid samples can be acquired and differentiated with one Arrow. A five-point standard addition curve is constructed to measure the concentration of the solvated analyte. Unmodified commercial components of the analysis system include the fiber itself, the Orbitrap and AccuTOF mass spectrometer platforms, and the conditioning gas chromatograph inlet. Machine diagrams for the SPME-DART interface and Arrow fiber holder are included.

Study on Seepage Characteristics of Grouting Slurry for Water-Absorbing Mudstone with Rough Fissure.

Based on the computed tomography scanning, which abbreviation is CT scanning, and fractal theory, geometric parameters of mudstone fissures are obtained. The physical model of a single fissured channel is obtained in combination with Barton standard curves and 3D printing technology, and similar materials of mudstone are developed based on the water absorption of natural mudstone to prepare single fissured water-absorbing grouting test blocks with different roughness levels for the grouting simulation testing. By analyzing the viscosity change characteristics of grouting slurry before and after grouting, the seepage characteristics of the grouting slurry in the rough fissures of the water-absorbing mudstone are revealed. The results show that when the roughness is small, the grouting slurry will have an obvious water loss effect after passing through mudstone fissures. However, with the flow of the slurry, the water loss effect of the subsequent grouting slurry will be weakened. For fissures with high roughness, the water absorption properties of the rough surfaces and the walls of the mudstone fissures work together, leading to the sedimentation and blockage of the fissure channels, thereby hindering the flow of slurry.

Lithological and Structural Factors Affecting Groundwater Occurrence in Eruwa, South West Nigeria

The subsurface Lithological and Structural framework was investigated to understand its effects on groundwater aquiferous occurrence in this study, underlined by the Precambrian Basement Complex of Nigeria, with granite, gneiss, and schist occurring as the dominant rock types. To successfully map the subsurface, fifty-two (52) Vertical Electrical Sounding points were probed to a depth of current electrode spacing of 100m depth to obtain the variation in the resistivity measurement of the underlying weathered basement and basement rock in the subsurface. Apparent resistivity values and current electrode spacing are plotted on a bi-logarithm plot and correlated to standard curves to estimate subsurface layers' depth, thickness, and resistivity values. WinResist software uses a mathematical algorithm to estimate further the geoelectric parameters to find the best-fit model that matches the observed data. Golden Surfer software was used to represent the geoelectric parameters to aid in geospatial representation. Results show 3-5 lithological layers, which include Topsoil, Clay, Laterite, Sand, Sandy Clay, and Fresh Basement with resistivity value range 82.1Ωm - 2648.2Ωm, 21.8Ωm - 98.4Ωm, 102.3Ωm -167.5Ωm, 404.6Ωm - 2468.2Ωm and 606.8Ωm - 20,535.90Ωm indicating a weathered and fresh unweathered basement rocks layers with H, KH, HA, HKH, KHKH, QH and A geophysical curve which are also typical geometry of weathered material and limited or no fractures basement rock layer. Basement rock resistivity, Overburden thickness, Reflection coefficient, longitudinal conductance, Anisotropy coefficient range (606.8Ωm-20535.9Ωm, 2.6m - 35.6m, 0.3-1.0, 0.01-0.86 and 0.7-3.3) respectively which a typical value of shallow to deep overburden layer with limited or no-detected fracture basement rock). Incorporating the geoelectric parameters value obtained and calculated reveal limited structural deformation of the basement rocks to yield fracture capable of creating secondary porosity in the area while the lithology of the weathered layers becomes the exploitable source for groundwater recovery in the study area.&#x0D;

Small- and medium-sized rice fields identification in hilly areas using all available sentinel-1/2 images

BackgroundMastering the spatial distribution and planting area of paddy can provide a scientific basis for monitoring rice production, and planning grain production layout. Previous remote sensing studies on paddy concentrated in the plain areas with large-sized fields, ignored the fact that rice is also widely planted in vast hilly regions. In addition, the land cover types here are diverse, rice fields are characterized by a scattered and fragmented distribution with small- or medium-sized, which pose difficulties for high-precision rice recognition.MethodsIn the paper, we proposed a solution based on Sentinel-1 SAR, Sentinel-2 MSI, DEM, and rice calendar data to focus on the rice fields identification in hilly areas. This solution mainly included the construction of rice feature dataset at four crucial phenological periods, the generation of rice standard spectral curve, and the proposal of spectral similarity algorithm for rice identification.ResultsThe solution, integrating topographical and rice phenological characteristics, manifested its effectiveness with overall accuracy exceeding 0.85. Comparing the results with UAV, it presented that rice fields with an area exceeding 400 m2 (equivalent to 4 pixels) exhibited a recognition success rate of over 79%, which reached to 89% for fields exceeding 800 m2. ConclusionsThe study illustrated that the proposed solution, integrating topographical and rice phenological characteristics, has the capability for charting various rice field sizes with fragmented and dispersed distribution. It also revealed that the synergy of Sentinel-1 SAR and Sentinel-2 MSI data significantly enhanced the recognition ability of rice paddy fields ranging from 400 m2 to 2000 m2.

Absolute quantitation of human wild-type DNAI1 protein in lung tissue using a nanoLC-PRM-MS-based targeted proteomics approach coupled with immunoprecipitation

BackgroundDynein axonemal intermediate chain 1 protein (DNAI1) plays an essential role in cilia structure and function, while its mutations lead to primary ciliary dyskinesia (PCD). Accurate quantitation of DNAI1 in lung tissue is crucial for comprehensive understanding of its involvement in PCD, as well as for developing the potential PCD therapies. However, the current protein quantitation method is not sensitive enough to detect the endogenous level of DNAI1 in complex biological matrix such as lung tissue.MethodsIn this study, a quantitative method combining immunoprecipitation with nanoLC-MS/MS was developed to measure the expression level of human wild-type (WT) DNAI1 protein in lung tissue. To our understanding, it is the first immunoprecipitation (IP)-MS based method for absolute quantitation of DNAI1 protein in lung tissue. The DNAI1 quantitation was achieved through constructing a standard curve with recombinant human WT DNAI1 protein spiked into lung tissue matrix.ResultsThis method was qualified with high sensitivity and accuracy. The lower limit of quantitation of human DNAI1 was 4 pg/mg tissue. This assay was successfully applied to determine the endogenous level of WT DNAI1 in human lung tissue.ConclusionsThe results clearly demonstrate that the developed assay can accurately quantitate low-abundance WT DNAI1 protein in human lung tissue with high sensitivity, indicating its high potential use in the drug development for DNAI1 mutation-caused PCD therapy.

Establishment of a targeted analysis method for gangliosides in mouse tissues by HILIC-ESI-MS/MS.

Gangliosides play an imperative role in cell signaling, neuronal recovery, apoptosis, and other physiological processes. For example, GM3 can regulate hypothalamic leptin resistance and control energy homeostasis, GD3 can mediate cell proliferation and differentiation and induce apoptosis, and GQ1b can stimulate neurogenesis. Therefore, the present study sought to establish and optimize the targeted analysis method for ganglioside subclasses and their molecular species using hydrophilic interaction liquid chromatography-triple quadrupole-MS/MS (HILIC-QQQ-MS/MS). Additionally, the fragmentation pattern of different ganglioside subclasses and their retention time patterns were analyzed, providing more accurate qualitative results. The limit of quantitation (LOQ) was as low as 10-4ng. Moreover, the molecular species of gangliosides in the liver, cortex, and hypothalamus of C57BL/6 mice were analyzed using the established method. A total of 23 ganglioside subclasses with 164 molecular species, including 40 O-acetylated ganglioside molecular species and 28 NeuGc ganglioside molecular species, were identified using the semi-quantitative analysis method of anexternal standard curve corrected by an internal standard. In addition to NeuGc gangliosides, the contents of ganglioside subclasses were more abundant in the mouse brain than those in the mouse liver; especially, the contents of unsaturated gangliosides in the hypothalamus were much higher than those in the liver. Among them, O-acetylated gangliosides were detected only in the cortex and hypothalamus at a concentration of up to 100μg/mg protein (40 molecular species). Overall, the proposed method expanded the detectable number of ganglioside subclasses and molecular species in biological samples and provided more opportunities for further study of the biological functions of gangliosides.

Development of a Sensitive and Specific Quantitative RT-qPCR Method for the Detection of Hepatitis E Virus Genotype 3 in Porcine Liver and Foodstuff

As an international and zoonotic cause of hepatitis, hepatitis E virus (HEV) poses a significant risk to public health. However, the frequency of occurrence and the degree of contamination of food of animal origin require further research. The aim of this study was to develop and validate a highly sensitive quantitative RT-qPCR assay for the detection and quantification of HEV contamination in porcine liver and food. The focus was on genotype 3, which is most common as a food contaminant in developed countries and Europe. The selected assay has its target sequence in the open reading frame 1 (ORF1) of the HEV genome and showed good results in inclusivity testing, especially for HEV genotype 3. The developed assay seems to show high efficiency and a low intercept when compared to other assays, while having a comparable limit of detection (LOD). In addition, a standard curve was generated using artificially spiked liver to provide more accurate quantitative results for contamination assessment and tracking in this matrix. Application of the assay to test 67 pig livers from different origins resulted in a positivity rate of 7.5%, which is consistent with the results of numerous other prevalence studies. Quantitative detection of the viral genome in the food chain, particularly in pig livers, is essential for understanding the presence and evolution of HEV contamination and thus ensures consumer safety.

Silver nanoparticles enhanced enzyme-linked immunosorbent assay (ELISA) detection of cancer testis antigens (CTAs).

The Enzyme-Linked Immunosorbent Assay (ELISA) has been a cornerstone technique in laboratory medicine for over 55 years, relying on the specific binding of antibodies to antigens. ELISA's widespread use stems from its ability to detect low concentrations, its specificity, reproducibility, and potential for high-throughput screening. However, its sensitivity has limitations, prompting the exploration of innovative methods to improve the limit of detection (LOD). Nanoparticles provide a promising platform for enhancing ELISA sensitivity. Due to their high surface-to-volume ratio, they offer increased binding sites for capture elements and reporting tags, leading to amplified analytical signals. Recent studies have demonstrated improved sensitivity in ELISA through nanoparticle application, yielding faster detection times and enhanced sensitivities. This study investigates the potential of 50 nm citrate-capped silver nanoparticles to enhance ELISA's performance in quantifying cancer testis antigens (CTAs). In our study, we used the Human NY-ESO-1 ELISA kit (for research purposes) to determine the concentration of CTAs in randomly selected samples from healthy (n=89) and oncological (n=80) subjects, aged 18-75. We employed 50 nm citrate-capped silver nanoparticles (AGCB50-1M, BioPure Silver Nanoparticles - bare citrate, nano-Composix, San Diego, CA, USA). ELISA reactions followed the manufacturer's instructions, and data processing aligned with the same guidelines. Absorbance (OD) measurements occurred at 450 nm, influencing nanoparticle selection. Each ELISA well contained 5 ml of nanoparticles' stock solution with specified concentrations. CTAs concentrations were derived from the standard curve through CurveExpert Basic software. Statistical analysis was performed using SPSS v. 27 software, with p-values indicating significance if <0.03. The study adhered to Helsinki Declaration principles and received ethical approval. Participants provided informed written consent. The increased concentration values of CTAs for healthy individuals and cancer patients were determined in the case of the application of silver nanoparticles. The usage of nanoparticles can enhance the sensitivity of the ELISA method and positively influence its specific detection limit.

Deriving location-specific synthetic seasonal hyetographs using GPM records and comparing with SCS curves

Abstract The hyetograph represents the temporal spread of rainfall intensity occurring at a point or over a watershed during a storm. The importance of regionally derived/developed hyetographs and the pooled sets of categorical seasonal curves on intensity-duration, intensity-depth, and depth-duration are of multifarious conveniences and importance. Twenty-one years of daily and sub-daily rainfall records (2000–2020) regained via satellite-observed precipitation products were examined and used to retrieve a valid understanding towards annual, monthly, daily, and hourly based variability of rainfall across six different stations. An attempt was made to compare the shapes of synthesized seasonal rain mass curves with that of the historic Soil Conservation Service (SCS) mass curve. The results indicate that the location-specific patterns and trends of curves do not align closely with any historical SCS curves or theoretical curves prevalent in the literature and commonly adopted. It has been observed that region-specific rainfall and its temporal distributions exhibit unique trends, not necessarily conforming to the standard SCS-based curves categorized as Types I, Ia, II, and III. This emphasizes the need to rely more on region-specific curves rather than instinctively adopting a standard set of curves.

Determination of Adsorption Capacity of Novel Molecularly Imprinted Materials for Herbicides

In order to improve the traditional method of adsorbing water residues and improve the adsorption efficiency, we prepared molecularly imprinted polymer modified by eutectic solvent and estabLish molecularly imprinted polymer adsorbent based on eutectic solvent. Based on the standard curve of atrazine, the adsorption capacity of the molecularly imprinted materials for atrazine was determined. It is beneficial for the preparation of molecularly imprinted materials based on eutectic solvent and the feasibiLity of their appLication in herbicide adsorption. Methods: using choLine chloride and methacryLic acid to prepare low melting solvent, atrazine as template molecule, molecularly imprinted polymer was prepared. Using this kind of molecularly imprinted polymer as adsorbent, the following experiments were carried out: 1. The standard curve of atrazine was drawn by HPLC; 2. The adsorption capacity of the new molecularly imprinted polymer was tested; 3. The reusabiLity of the adsorption material was verified. Results: through the static and dynamic adsorption capacity experiments, des-mip had the highest adsorption performance, and showed better absorption effect than MIP. In the reusability experiment, des-mip shows better recovery under the premise of introducing des. The intra day and inter day recoveries of des-mip were 74.9% - 78.8% and 83.8% - 86.8%, respectively. The intra day and inter day recoveries of aa-mip were 69.2% - 72.3% and 68.5% - 71.9%, respectively. The relative standard deviation of des-mip and aa-mip was less than 2%. The reusability of des-mip and aa-mip is verified. Conclusion: the molecular imprinted polymer with eutectic solvent has better herbicide removal ability than the other three materials.

Abstract TP162: Polyamine Levels Are Elevated After Intracerebral Hemorrhage

Introduction: Intracerebral hemorrhage (ICH) has high morbidity and mortality without available targets for intervention. Polyamines are metabolites implicated in neurological diseases such as traumatic brain injury, Alzheimer’s Disease, and ischemic stroke. No studies have evaluated polyamines as they relate to ICH occurrence or outcomes. In this pilot study, we sought preliminary data on whether polyamines could be potential novel targets to improve outcomes after ICH. Methods: We analyzed plasma samples from 7 ICH cases and 10 control participants from the Genetics and Environmental Risk Factors for Stroke (GERFHS) IV study for polyamine measurements using Capillary Electrophoresis with Laser Induced Fluorescence Detection with the modality of Micellar Electrokinetic Chromatography. Plasma samples were deproteinized and derivatized with Fluorescein Isothiocyanate. Samples were spiked with standard solutions and compared with standard curves developed per each polyamine. We report median age and sex of the cohort. Peak spermine, spermidine and putrescine levels were compared using a student’s t-test. Results: In this pilot study of participants enrolled into GERFHS IV (median age 67 vs 61, cases vs controls respectively, 50% female) all three unacetylated polyamine levels were higher in cases. Although sample size is modest, there was a trend towards increased spermidine levels with higher mRS at 90 days (r 2 = 0.3342) (Figure 1). Conclusions: For the first time, we have shown that polyamines are elevated after ICH, and that higher polyamine levels may be associated with worse outcomes. This preliminary data supports further evaluation of polyamines as potential targets to improve outcomes after ICH in a larger cohort.

Determination of 55 Veterinary Antibiotics in Chicken Manure Using Ultra-High-Performance Liquid Chromatography – Tandem Mass Spectrometry (UPLC-MS/MS)

A highly efficient method for the detection and quantification of 55 veterinary antibiotics (VAs) in chicken manure belonging to six drug classes using solid-phase extraction (SPE) and ultrahigh-performance liquid chromatography–tandem mass spectrometry (UPLC–MS/MS) was developed. The mixture of EDTA–McIlvaine buffer (pH 3.0) and the organic extractant (methanol–acetonitrile, 1:3, v/v) was used to isolate the target VAs from freeze-dried chicken manure. The extract was purified by a hydrophile–lipophile balance cartridge. All antibiotics showed excellent linear relationships in the range between 1 and 100 µg/kg with the coefficients of determination of the standard curves above 0.990. The recoveries of antibiotics were between 35.66% and 103.54% using matrix-matched calibration for quantification. The limits of detection and quantification were from 0.01 to 1.59 µg/kg and 0.04 to 4.76 µg/kg, respectively. The method was demployed to determine VAs in chicken manure from 12 farms, revealing contamination in all samples. A total of 13 VAs belonging to six classes were detected with concentrations up to 41.47 mg/kg. The presence of high concentrations of antibiotic residues in poultry manure poses a potential risk for environmental contamination. This work has identified significant differences in the types of VAs compared to literature reports. Additionally, it detected pleuromutilin antibiotics in chicken manure for the first time.

Development of a fast and sensitive RT-qPCR assay based on SYBR® green for diagnostic and quantification of Avian Nephritis Virus (ANV) in chickens affected with enteric disease

BackgroundEnteric viruses are among the most prominent etiological agents of Runting-Stunting Syndrome (RSS). The Avian Nephritis Virus (ANV) is an astrovirus associated with enteric diseases in poultry, whose early diagnosis is essential for maintaining a good poultry breeding environment. ANV is an RNA virus that rapidly mutates, except for some conserved regions such as ORF1b. Therefore, the approach of a diagnostic method based on fast-RT-qPCR using SYBR® Green that focuses on the amplification of a fragment of ORF1b is presented as a feasible alternative for the diagnosis of this viral agent. In this study, the proposed assay showed a standard curve with an efficiency of 103.8% and a LoD and LoQ of 1 gene viral copies. The assay was specific to amplify the ORF 1b gene, and no amplification was shown from other viral genomes or in the negative controls. 200 enteric (feces) samples from chickens (broilers) and laying hens with signs of RSS from Ecuadorian poultry flocks were examined to validate the proposed method.ResultsUsing our method, 164 positive results were obtained out of the total number of samples run, while the presence of viral RNA was detected in samples collected from one day to 44 weeks old in both avian lines.ConclusionsOur study presents a novel, rapid, robust, and sensitive molecular assay capable of detecting and quantifying even low copy numbers of the ANV in commercial birds, therefore introducing a handy tool in the early diagnosis of ANV in enteric disease outbreaks in poultry.

Property parameter determination in individual layers for separately fractured wells with commingled production in multi-layered reservoirs

At present, without any separate rate test for each layer, there is no way to determinate the properties of individual layers for separately fractured wells with commingled production in multi-layered reservoirs. In order to address this issue, much research work was performed and elucidated in this article. To begin with, we illustrated a basic physical model for a separately fractured well in a multi-layered reservoir. Next, we stated the common determination method that can only be used to gain the average properties of multi-layered reservoirs. Then, according to the physical model, we newly established a mathematical model and plotted standard well-test type curves; additionally, we also discussed why we cannot determinate the properties of individual layers by using the new well-test model. What’s more, we presented a new method to determinate the properties of individual layers. Moreover, we compared the advantages and disadvantages among the three methods. In addition, by using the new determination method, we particularly took two field wells as examples to demonstrate how to determine the properties of individual layers. The proposed new method was validated by use of the common method, the new well-test model and the microseismic monitoring results. At the end, we summarized the research conclusions and indicated that the new method was a good tool to determinate the properties of individual layers in multi-layered reservoirs.

Quantitative analysis of the quality constituents of Lonicera japonica Thunberg based on Raman spectroscopy

Quantitative analysis of the quality constituents of Lonicera japonica (Jinyinhua [JYH]) using a feasible method provides important information on its evaluation and applications. Limitations of sample pretreatment, experimental site, and analysis time should be considered when identifying new methods. In response to these considerations, Raman spectroscopy combined with deep learning was used to establish a quantitative analysis model to determine the quality of JYH. Chlorogenic acid and total flavonoids were identified as analysis targets via network pharmacology. High performance liquid chromatograph and ultraviolet spectroscopy were used to construct standard curves for quantitative analysis. Raman spectra of JYH extracts (1200) were collected. Subsequently, models were built using partial least squares regression, Support Vector Machine, Back Propagation Neural Network, and One-dimensional Convolutional Neural Network (1D-CNN). Among these, the 1D-CNN model showed superior prediction capability and had higher accuracy (R2 = 0.971), and lower root mean square error, indicating its suitability for rapid quantitative analysis.

Impacts of Flight Operations on the Risk of Runway Excursions

The Quick Access Recorder (QAR), as an onboard device used for monitoring and recording flight parameters, has been extensively installed on various types of aircraft. Recently, there has been a significant focus on studying the typical flight safety event of runway excursions based on QAR data. However, there is limited research that combines the analysis of runway excursion risks with flight operations, and there is also a scarcity of studies that divide the investigation of the landing phase into multiple key stages. In this paper, we propose a comparative analysis of operational characteristics and risks associated with runway excursions from the perspective of operational styles. A total of 2087 flights were classified on the basis of touchdown distance, taxiing distance, and magnetic heading changes and were divided into three styles based on these indicators. Subsequently, we analyze flight operations and attitudes at five key stages: runway threshold, flare, speed brake deployment, touchdown, and reverse thrust activation. Furthermore, we employ the selection criteria of pilot proficiency levels to filter out standard operational curves. The curve similarity is used to compare the difference between the actual operating curves and the standard curves. Finally, we employ typical correlation analysis to explore the relationship between touchdown distance and operational variances. The findings indicate that Style 1 pilots exhibit the lowest probability of runway excursions, yet their maneuvers potentially elevate the risk of hard landing events.

Individual subpulses of PSR B1916+14 and their polarization properties

ABSTRACT The individual subpulses of pulsars are regarded as their basic emission components, providing invaluable information for our understanding of the radio emission process in the pulsar magnetosphere. Nevertheless, subpulses are overlapped with each other along the rotation phase for most pulsars, making it difficult to study the statistical properties of subpulses. Among the pulsars observed by the Five-hundred-meter Aperture Spherical radio Telescope (FAST), PSR B1916+14 has a large number of isolated well-resolved subpulses in the high-time-resolution observations, having a typical width of 0.15 ms and a high linear polarization. We find that the number distribution of subpulses contributes dominantly to the mean profile. According to the emission geometry, these emission units come from a region roughly 155 km above the polar cap in the pulsar magnetosphere, and the length-scale of the basic emission units is approximately 120 m. The deviations of the polarization position angles for these single subpulses from the standard S-shaped curve are closely related to their fractional linear and circular polarization, and the large deviations tend to come from drifting subpulses.