Publications by authors named "Kejun Zhong"

Diisooctyl phthalate (DIOP), a common phthalate plasticizer, is frequently encountered in everyday life. Despite its widespread use, there is a dearth of toxicological research on DIOP, resulting in incomplete knowledge of its potential harmful effects. Our current research endeavored to provide a comprehensive evaluation of DIOP's toxicological profile using both cellular and Caenorhabditis elegans models as our in vitro and in vivo study subjects.

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This article proposes a novel approach for improving the efficiency of fragrance designing and the accuracy of automatic fragrance formula creation based on empirical fragrance formulas and graph traversal algorithms. By effectively extracting the composition information and further analyzing the combination of fragrance materials in 210 fragrance formulas, a relational network model was constructed in the form of a graph to illustrate the relationship between the ingredients used in the formulas. Additionally, a fragrance ingredients information database of 344 common ingredients was constructed and used as a reference for perfumers when setting algorithmic constraints based on their experience.

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Article Synopsis
  • * This method uses geometric constraints and epipolar rectification to accurately calibrate camera angles and eliminate incorrect 3D point pairs, leading to a refined parallax map without needing extra images.
  • * Experimental validation on a step block and standard ball showed the method's effectiveness, achieving a root mean square error of only 0.052 mm, indicating high precision in 3D measurements.
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In this research, an ammonium perchlorate/polydopamine (AP/PDA) core-shell composite was prepared in a non-aqueous solution to reduce the mechanical sensitivity of ammonium perchlorate (AP). The result showed that the AP/PDA core-shell composite could be successfully constructed in ethyl acetate solution with an AP recovery rate that reached 86%. The mechanical sensitivity of the obtained AP/PDA core-shell composite was significantly reduced with a PDA content of only 0.

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The Fourier deconvolution ion mobility spectrometer (FDIMS) offers multiplexing and improves the resolving power and signal-to-noise ratio. To evaluate the FDIMS as a detector for gas chromatography for the analysis of complex samples, we connected a drift tube ion mobility spectrometer to a commercial gas chromatograph and compared the performance including resolving power, sensitivity, and linear range using 2,6-di‑tert-butylpyridine. Mixed standards were also injected into the tandem system to evaluate the performance under optimized conditions.

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The aroma of mint is well-liked by the public, and key flavor odorants in mint aroma had been found, but how these molecules interact and form a satisfying odor remains a challenge. Quality, intensity, and pleasantness are our most basic perceptions of aromas; both intensity and pleasantness can be quantified. However, compared to intensity, research on pleasantness was lacking.

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Conductive hydrogels have been in huge demand in biomedical and wearable electronics. However, the application of traditional conductive hydrogels is largely limited due to their poor mechanical properties. Here, a conductive hydrogel with excellent mechanical strength and swelling resistance properties is prepared by ion cross-linking, directional freeze-drying, and rehydration.

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A Gas chromatography-mass spectrometry (GC-MS) data analysis algorithm is proposed. The mass spectrum at the top of the chromatographic peak is the spectrum to be solved. A certain amount of related reference spectra is retrieved from the spectral library, then, the equation of the chromatographic response value of each pure component is solved.

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The study of spatial distribution characteristics of the adsorbed compounds for absorbent materials has significant importance in understanding the behaviors of aerosols while they migrating in the absorbent materials. Herein, for the first time, desorption corona beam ionization-mass spectrometry (DCBI-MS) has proposed for direct in-situ analysis of adsorbed aerosol for absorbent materials. DCBI is a novel atmospheric pressure chemical ionization (APCI)-related technique developed by our group in recent years.

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Representing a compound by a numerous structural descriptors becomes common in quantitative structure-activity relationship (QSAR) studies. As every descriptor carries molecular structure information more or less, it seems more advisable to investigate all the possible descriptor vectors rather than traditional variable selection when building a QSAR model. Based on particle swarm optimization (PSO) algorithm, a more flexible descriptor selection and model construction method variable-weighted support vector machine (VW-SVM) is proposed.

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We applied the random forest method to discriminate among different kinds of cut tobacco. To overcome the influence of the descending resolution caused by column pollution and the subsequent deterioration of column efficacy at different testing times, we constructed combined peaks by summing the peaks over a specific elution time interval Deltat. On constructing tree classifiers, both the original peaks and the combined peaks were considered.

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Article Synopsis
  • An accelerated solvent extraction (ASE) method has been optimized for extracting volatile and semi-volatile components from cut tobacco, improving extraction efficiency.
  • The ASE method outperforms traditional simultaneous distillation extraction (SDE) by providing higher yields, requiring less time and solvent, and simplifying the process.
  • Analysis of 36 cigarette samples from six brands using gas chromatography/time-of-flight mass spectrometry (GC-TOFMS) and partial least squares-discriminant analysis demonstrates the effectiveness of ASE for distinguishing between different cigarette brands.
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Despite the significance of cigarette smoke for carcinogenesis, the molecular mechanisms that lead to increased susceptibility of human cancers are not well-understood. In our present study, the oncogenic transforming effects of cigarette smoke condensate (CSC) were examined using papillomavirus-immortalized human bronchial epithelial cells (BEP2D). Growth kinetics, saturation density, resistance to serum-induced terminal differentiation, anchorage-independent growth and tumorigenicity in nude mice were used to investigate the various stages of transformation in BEP2D cells.

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A combined approach of subwindow factor analysis and orthogonal projection resolution was used to analyze the volatile components of cut tobacco samples from different sources. After extracted with simultaneous distillation and extraction method, the volatile components in cut tobacco from five different locations were detected by GC-MS. Then, the qualitative and quantitative analysis of the volatile components of cut tobacco from Changde area was completed with the help of subwindow factor analysis resolving two-dimensional original data into pure mass spectra and chromatograms.

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In this paper, chromatographic fingerprint was firstly used for quality control of tobacco flavors. Based on gas chromatography-mass spectrometry (GC-MS) and combined chemometrics methods, a simple, reliable and reproducible method for developing chromatographic fingerprint of coffee flavor, one of tobacco flavors, was described. Six coffee flavor samples obtained from different locations were used to establish the fingerprint.

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A fast, accurate, sensitive, selective and reliable method using reversed-phase high-performance liquid chromatography-mass spectrometry coupling with an electrospray ionization interface was developed and validated for the determination of finasteride in human plasma. After deprotienation with acetonitrile, centrifugation, evaporation to dryness and dissolving in mobile phase, satisfactory separation was achieved on a Hypersil-Keystone C(18) reversed-phase column using a mobile phase consisting of acetonitrile-water (46:54, v/v), 0.1% acetic acid and 0.

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The effect of N'-nitrosonornicotine (NNN), one of the tobacco-specific nitrosamines, on the catalytic activity of glutamate dehydrogenase (GLDH) in the alpha-ketoglutarate amination, using reduced nicotinamide adenine dinucleotide as coenzyme, was studied by a chronoamperometric method. The maximum reaction rate of the enzyme-catalyzed reaction and the Michaelis-Menten constant, or the apparent Michaelis-Menten constant, were determined in the absence and presence of NNN. NNN remarkably inhibited the bio-catalysis activity of GLDH, and was a reversible competitive inhibitior with K(i), estimated as 199 micromol l(-1) at 25 degrees C and pH 8.

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Linear sweep anodic stripping voltammetry was applied to determine the concentration of free copper ions in the process of binding copper to human serum albumin (HSA) on the mercaptoethane sulfonate modified gold electrode surface. A kinetic model of two consecutive steps for the process of binding copper to HSA was first proposed on the basis of the electrochemical results and compared with a parallel kinetic response model by using residual analysis. The experimental data of the stripping peak currents with time was fitted according to the model and the kinetic parameters, binding rate constants, k1 and k2, were estimated to be 0.

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