Association of vaccination, international travel, public health and social measures with lineage dynamics of SARS-CoV-2.

Continually emerging SARS-CoV-2 variants of concern that can evade immune defenses are driving recurrent epidemic waves of COVID-19 globally. However, the impact of measures to contain the virus and their effect on lineage diversity dynamics are poorly understood. Here, we jointly analyzed international travel, public health and social measures (PHSM), COVID-19 vaccine rollout, SARS-CoV-2 lineage diversity, and the case growth rate (GR) from March 2020 to September 2022 across 63 countries. We showed that despite worldwide vaccine rollout, PHSM are effective in mitigating epidemic waves and lineage diversity. An increase of 10,000 monthly travelers in a single country-to-country route between endemic countries corresponds to a 5.5% (95% CI: 2.9 to 8.2%) rise in local lineage diversity. After accounting for PHSM, natural immunity from previous infections, and waning immunity, we discovered a negative association between the GR of cases and adjusted vaccine coverage (AVC). We also observed a complex relationship between lineage diversity and vaccine rollout. Specifically, we found a significant negative association between lineage diversity and AVC at both low and high levels but not significant at the medium level. Our study deepens the understanding of population immunity and lineage dynamics for future pandemic preparedness and responsiveness.

Experimental Study of the Fracture Network Expansion Mechanism and Three-Dimensional Reconstruction Characteristic of High-Rank Coal in Guizhou Province, China.

To better understand the fracture propagation characteristics and spatial distribution pattern of a high-rank coal reservoir during hydraulic fracturing, a true triaxial physical simulation device was used to conduct a hydraulic fracturing experiment on large-sized raw coal from Zhijin, Guizhou Province, China. Computed tomography technology was used to scan the three-dimensional morphology of the fracture network before and after fracturing, then AVIZO software was used to reconstruct the internal fractures of the coal sample, and fractal theory was used to quantify the fractures. The results show that (1) the sudden increase of the pump pressure curve and acoustic emission signal is an important identification feature of hydraulic fractures, and the in situ stress difference coefficient plays a leading role in the complexity of coal and rock fractures. (2) When a hydraulic fracture encounters a primary fracture in the process of expansion, the opening of the primary fracture, the penetration, bifurcation, and turning of the hydraulic fracture are the main reasons for the formation of complex fractures, and the existence of a large number of primary fractures is the basis for the formation of complex fractures. (3) The fracture shape of coal hydraulic fracturing can be divided into three categories: complex fracture, plane fracture + cross fracture, and inverted T-shaped fracture. The fracture shape is closely related to the original fracture shape. The research results of this paper provide strong theoretical and technical support for coalbed methane mining design such as Zhijin high-rank coal reservoirs.

Study on Mechanical Properties and Crack Propagation of Raw Coal with Different Bedding Angles based on CT Scanning.

The deformation and damage characteristics of coal are the important foundation that affects the fracturing potential of coal reservoirs and the development plan of coalbed methane (CBM). To reveal the influence regulation of primary fractures and the bedding angle of coal on its failure and provide theoretical basis for CBM development, raw coal samples of no 16 coal seam in Wenjiaba Coal Mine, Zhijin County, Bijie City with different bedding angles were selected as the research object, and uniaxial compression tests were carried out on them, and CT scanning and crack reconstruction before and after sample failure were carried out. The results show that (1) the compressive strength, elastic modulus, and Poisson's ratio of coal show a strong bedding angle effect, and the changing trend of each index is basically the same. The coal samples with bedding angles of 0 and 90° are the highest, while the coal samples with bedding angles of 30° are the lowest, and the overall distribution is an approximate "U" with the increase in bedding angle. With the increase in bedding angle of 0-90°, the failure modes of coal samples are tension-shear combined failure, shear-slip failure, and splitting tension failure in turn. (2) The observation of raw coal and CT scanning show that the primary cracks in coal samples are well developed, especially in the lower part of 0° samples, the cracks in 30° samples, 60° samples, and 90° samples are evenly distributed and develop at a certain angle with the weak bedding surface, and microcracks parallel to and nearly perpendicular to the weak bedding surface are developed in 45° samples. At the same time, banded minerals in coal and rock samples are also well developed. (3) The characteristics of crack propagation and evolution in coal samples with different bedding dip angles are significantly different. The bedding dip angles and primary cracks of coal seam have a great influence on crack propagation. With different bedding angles, the propagation modes are different. The crack propagation mainly includes two ways: forming a certain angle with bedding and extending along the bedding plane. (4) The fracture characteristic parameters of coal in the primary state and after failure have the same law with the bedding dip angle, showing a trend of high at both ends and low in the middle, which is an irregular "U"-shaped distribution and has a similar law with mechanical characteristic parameters.

[Modified QuEChERS method based on multi-walled carbon nanotubes coupled with gas chromatography-tandem mass spectrometry for the detection of 10 pyrethroid pesticide residues in tea].

A modified QuEChERS method, based on multi-walled carbon nanotubes (MWCNTs), was established for the detection of 10 pyrethroid pesticides (cyfluthrin, flucythrinate, fenpropathrin, bifenthrin, cyhalothrin, permethrin, cypermethrin, etofenprox, fenvalerate, deltamethrin) in tea, in combination with gas chromatography-tandem mass spectrometry (GC-MS/MS). The purification effects and dosages of four carbon nanomaterials, viz. single-walled carbon nanotubes (SWCNTs), MWCNTs, amino-modified MWCNTs, and graphene, were compared. An orthogonal experimental design was used to determine the optimal experimental conditions for sample pretreatment. The experimental factors governing the process were analyzed using variance. The results showed that the optimized sample pretreatment parameters were as follows. Acetonitrile was used as the extraction solvent with ultrasonic extraction for 35 min, while 60 mg MWCNTs, 200 mg PSA, and 200 mg C18, were used as purifiers. The effects of the extraction solvent and the carbon nanomaterials used on the recoveries of the 10 pyrethroid pesticides were significantly different (p<0.001), and the effect of extraction time on the recoveries was statistically different (p<0.05). The dosage of carbon nanomaterials had no significant effect on the recoveries (p>0.05). Good linearities were observed for the 10 pyrethroid pesticides in the concentration range of 0.01-2 mg/L. The limits of detection (LODs) and limits of quantification (LOQs) were in the ranges of 0.001-0.01 mg/kg and 0.005-0.04 mg/kg, respectively. The average recoveries of the pyrethroid pesticides spiked into blank samples of green tea were 91.4%-109.7%, and the relative standard deviations were 0.12%-9.80% (n=6). Furthermore, the matrix effects (MEs) of scented green tea, green tea, and black tea were evaluated. It was found that the addition of MWCNTs to the purifier can effectively reduce the matrix effect in green tea and black tea matrices. The developed method and the national standard method were used to detect the residues of the 10 pyrethroid pesticides in 120 tea samples available in the market. The results showed that cyfluthrin, deltamethrin, fenvalerate, permethrin, fenpropathrin, cypermethrin, bifenthrin and cyhalothrin were detected, and the contents obtained with the two methods were similar. Although pyrethroids were detected in most tea samples, the contents of all pesticide residues were below the maximum residue limits (MRLs). Therefore, the developed method is suitable for the rapid quantitative analysis of pesticide residues in tea.

Establishment and Validation of a Nomogram for Tonsil Squamous Cell Carcinoma: A Retrospective Study Based on the SEER Database.

This study aimed to establish and validate a comprehensive nomogram for predicting the cause-specific survival (CSS) probability in tonsillar squamous cell carcinoma (TSCC). We screened and extracted data from the SEER (Surveillance, Epidemiology, and End Results) database for the period 2004 to 2016. We randomly divided the 7243 identified patients into a training cohort (70%) for constructing the model and a validation cohort (30%) for evaluating the model using R software. Multivariate Cox stepwise regression was used to select predictive variables. The concordance index (C-index), the area under the time-dependent receiver operating characteristics curve (AUC), the net reclassification improvement (NRI), the integrated discrimination improvement (IDI), calibration plotting, and decision-curve analysis (DCA) were used to evaluate the model. The multivariate Cox stepwise regression analysis successfully established a nomogram for the 1-, 3-, and 5-year CSS probabilities for TSCC patients. The C-index, AUC, NRI, and IDI were all showed that the model has good discrimination. The calibration plots were very close to the standard lines, indicating that the model has a good degree of calibration, and the DCA curve further illustrated that the model has good clinical validity. We have established the first nomogram for predicting the 1-, 3-, and 5-year CSS probabilities for TSCC based on a large retrospective sample. Our rigorous validation and evaluation indicated that the model can provide useful guidance to clinical workers making clinical decisions about individual patients.

Prognostic factors in patients with gallbladder adenocarcinoma identified using competing-risks analysis: A study of cases in the SEER database.

A competing-risks model was developed in this study to identify the significant prognostic factors and evaluate the cumulative incidence of cause-specific death in gallbladder adenocarcinoma (GBAC), with the aim of providing guidance on effective clinical treatments.All patients with GBAC in the Surveillance, Epidemiology, and End Results (SEER) database during 1973 to 2015 were identified. The potential prognostic factors were identified using competing-risks analyses implemented using the R and SAS statistical software packages. We calculated the cumulative incidence function (CIF) for cause-specific death and death from other causes at each time point. The Fine-Gray proportional-subdistribution-hazards model was then applied in univariate and multivariate analyses to test the differences in CIF between different groups and identify independent prognostic factors.This study included 3836 eligible patients who had been enrolled from 2004 to 2015 in the SEER database. The univariate analysis indicated that age, race, AJCC stage, RS, tumor size, SEER historic stage, grade, surgery, radiotherapy, chemotherapy and adjuvant therapy (RCT, SRT, SCT and SRCT) were significant factors affecting the probability of death due to GBAC. The multivariate analysis indicated that age, race, AJCC stage, RS status, tumor size, grade and SRT were independent prognostic factors affecting GBAC cancer-specific death. A nomogram model was constructed based on multivariate models for death related to GBAC.We have constructed the first competing-risks nomogram for GBAC. The model was found to perform well. This novel validated prognostic model may facilitate the choosing of beneficial treatment strategies and help when predicting survival.

[Identification of Nanfeng mandarin from different origins by using near infrared spectroscopy coupled with principal components analysis].

The identification of Nanfeng mandarins from different origins was developed by using near infrared spectroscopy (NIR) and principal components analysis (PCA). Mandarins from different places in one orchard, and from different orchards in three towns of Nanfeng county were studied. Also differences among Shaowu, Liucheng and Nanfeng were investigated. Furthermore, the effect of storage time of mandarins on the PCA model was considered. The results demonstrate that there was no clear diversity of the mandarins in one origin but great differences existed among different ones. And the storage time of mandarins played little role in the discrimination model. The method of multiple scattering correction (MSC) coupled with second derivative was selected to build PCA discrimination models compared with other data pretreatment methods. The proposed model would be a reference method for origin identification of Nanfeng mandarin.

Simultaneous determination of organophosphorus, organochlorine, pyrethriod and carbamate pesticides in Radix astragali by microwave-assisted extraction/dispersive-solid phase extraction coupled with GC-MS.

A simple, rapid and reliable method was proposed for the simultaneous determination of 27 pesticides (organophosphorus, organochlorine, pyrethroid and carbamate pesticides) in Radix astragali. The pesticides were extracted by acetonitrile and the experimental variables, such as temperature, extraction time and volume of acetonitrile, were optimized through orthogonal array experimental design. Cleanup of extracts was performed with dispersive-solid phase extraction using primary secondary amine (PSA) as the sorbent. The determination of pesticides in the final extracts was carried out by gas chromatography-mass spectrometry in selected ion monitoring mode (GC-MS, SIM). The linearity of the calibration curves is good in matrix-matched standard, and yields the coefficients of determination (R(2))≥0.99 for approximately 96% of the target analytes. Under optimized conditions, the average recoveries (six replicates) for most pesticides (spiked at 0.02, 0.1 and 0.2 mg kg(-1)) range from 70% to 120%, and RSDs are less than 17.2%.

Synthesis and application of hollow magnetic graphitic carbon microspheres with/without TiO2 nanoparticle layer on the surface.

Hollow magnetic graphitic carbon microspheres (HMGSs) with/without a TiO(2) nanoparticle layer on their surfaces are designed and synthesized by combining the bubble-template method, assembly of beta-cyclodextrin and Fe(3)O(4) stabilized by oleic acid and ammonia, and consequent graphitization reaction. HMGSs have potential in adsorption, enrichment, magnetic-assisted separation and drug delivery.

Determination of beta-lactamase residues in milk using matrix-assisted laser desorption/ionization Fourier transform mass spectrometry.

A selective, fast, and effective enzyme assay based on matrix-assisted laser desorption/ionization Fourier transform mass spectrometry (MALDI-FTMS) for quantifying beta-lactamase, an illegal additive in milk products, has been reported. The strengths of the mass spectrometric assay are its response to all substrate and products, simple and direct detection of the conversion of substrate, and facile determination of enzyme activity. Also, MALDI MS is tolerant to many buffer salts and reagents without the requirement of complicated sample pretreatment procedures. In this study, the approach was used to detect the presence of beta-lactamases (BLA) in milk samples. The amount of BLA that could be determined in a milk sample is 6 x 10(-3) U x mL(-1) by this approach. To test the strategy, it has been applied to the fortified milk (adding a BLA product known as an antimicrobial destroyer). It is then tested whether the pasteurization procedure of the milk process affects the activity of BLA in milk samples. This study offers a perspective into the utility of MALDI-FTMS as an alternative detection tool for BLA screening in milk.

A comprehensive two-dimensional normal-phase x reversed-phase liquid chromatography based on the modification of mobile phases.

A comprehensive orthogonal two-dimensional liquid chromatography (2D-LC) based on the modification of mobile phases was developed with a sample loop-valve interface. To improve the compatibility of mobile phases and analysis speed, some special solvents were chosen as the mobile phases, and the column temperature was elevated to decrease the viscosity of mobile phases of reversed-phase liquid chromatography (RPLC). Based on this principle, the first dimension was normal-phase liquid chromatography (NPLC) with a SiO2 column, and the second dimension was reversed-phase liquid chromatography containing two tandem C18 columns. 1,4-Dioxane was used in the NPLC mobile phase, and isopropyl alcohol was employed in the RPLC mobile phase. Moreover, the elevated column temperature enabled the reduction of the backpressure and using tandem C18 columns to improve the resolving power in RPLC. The new comprehensive 2D-LC system and applied strategy offered a novel idea for construction of 2D-LC system. A traditional Chinese medicine, Zhengtian pill, was used as the test sample to evaluate the constructed 2D-LC system. 876 peaks were detected, and the peak capacity reached 1740.

Electrophilic aromatic substitution and single-electron transfer (SET) by the phenylium ion in the gas phase: characterization of a long-lived SET intermediate.

Gas-phase mass spectrometric studies and calculations were performed for the reaction of naked phenylium ion with several benzene halides. From these reactions, the molecular ion for biphenyl as the predominant product was obtained only from the reaction of phenylium ions with iodobenzene and bromobenzene. Furthermore, through the collision-induced dissociation (CID) of the ion at m/z 281, the only dissociation observed is the loss of a phenyl radical, which indicates that a single-electron transfer (SET) mechanism might have occurred within the reaction. Additionally, according to the comparison between the CID experiments of those isomeric compounds of the sigma-complexes and the CID experiment of the ion at m/z 281 captured in the ion trap, we have also defined the captured ion at m/z 281 as an SET-intimate ion pair rather than those of sigma-complexes or the diphenyliodonium.

Monitoring enzyme reaction and screening of inhibitors of acetylcholinesterase by quantitative matrix-assisted laser desorption/ionization Fourier transform mass spectrometry.

A matrix-assisted laser desorption/ionization Fourier transform mass spectrometry (MALDI-FTMS)-based assay was developed for kinetic measurements and inhibitor screening of acetylcholinesterase. Here, FTMS coupled to MALDI was applied to quantitative analysis of choline using the ratio of choline/acetylcholine without the use of additional internal standard, which simplified the experiment. The Michaelis constant (K(m)) of acetylcholinesterase (AChE) was determined to be 73.9 micromol L(-1) by this approach. For Huperzine A, the linear mixed inhibition of AChE reflected the presence of competitive and noncompetitive components. The half maximal inhibitory concentration (IC(50)) value of galantamine obtained for AChE was 2.39 micromol L(-1). Inhibitory potentials of Rhizoma Coptidis extracts were identified with the present method. In light of the results the referred extracts as a whole showed inhibitory action against AChE. The use of high-resolution FTMS largely eliminated the interference with the determination of ACh and Ch, produced by the low-mass compounds of chemical libraries for inhibitor screening. The excellent correlation with the reported kinetic parameters confirms that the MS-based assay is both accurate and precise for determining kinetic constants and for identifying enzyme inhibitors. The obvious advantages were demonstrated for quantitative analysis and also high-throughput characterization. This study offers a perspective into the utility of MALDI-FTMS as an alternate quantitative tool for inhibitor screening of AChE.

[Preparation and optimization of polymer-based monolithic stationary phase for high performance liquid chromatography].

Unstirred in-situ polymerization was employed to directly produce glycidyl methacrylate-ethylene dimethacrylate copolymer (poly(GMA-co-EDMA)) monoliths. Mercury intrusion method was adopted to measure some parameters of the monoliths, such as pore size distribution, porosity and specific surface area. Effects of key variables such as composition of pore-forming solvent mixture, temperature and content of cross-linking reagent, divinyl monomer on porous structure of monoliths were studied. The optimization of preparation conditions was achieved. Homogeneous micro porous structure was observed in the monoliths by scanning electron microscope. The effect of flow rate on back pressure was investigated, and good permeability of the monolithic stationary phase was obtained. The monolithic column was also used for the separation of goat serum and five oligonucleotides, and the results proved that the monolithic column is suitable for the separation of biopolymers.

Preparation and evaluation of a large-volume radial flow monolithic column.

In this study, a 38 mL monolith with homogeneous porous structure was produced by a single polymerization from glycidyl methacrylate (GMA) and ethylene dimethacrylate (EDMA) in the presence of porogens and an initiator. The uniform temperature distribution within the reaction system was achieved by adding reactant mixture continuously and enhancing the heat transfer ability of the polymerization system. Homogeneous porous structure in the monolith was proved by SEM and the pore size distribution profiles measured by mercury intrusion porosimetry. Experimental results from proteins separation indicated that the dynamic capacity and resolution of radial flow monolithic column were independent of flow rates. Furthermore, the pressure drop on the column was linearly dependent on the flow rate and did not exceed 1.7 MPa even at a flow rate of 50 mL/min, which proved that the prepared monolith could be used in the quick separation and preparation of biopolymers.