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As of October 2022, the United Nations Office on Drugs and Crime (UNODC) Early Warning Advisory (EWA) has monitored over 1 150 new psychoactive substances (NPS) that had appeared in 137 countries and territories, including 76 substances that were notified for the first time in 2022. The increasing popularity of NPS has become a policy challenge and a major international concern, and poses potential risks for public health. Ketamine and ketamine analogues belong to β-keto-arylcyclohexylamines, which are classified into dissociative NPS due to their “dissociative anesthetic” effect. According to the monitoring data of the National Narcotics Laboratory, as of August 2022, ten ketamine structural analogues have been detected in China, including 2-(2-chlorophenyl)-2-(ethylamino) cyclohexan-1-one (NENK), 2-(3-methoxyphenyl)-2-(ethylamino) cyclohexan-1-one (MXE), 2-phenyl-2-(methylamino) cyclohexan-1-one (DCK), and 2-(2-fluorophenyl)-2-(methylamino)cyclohexan-1-one (2-FDCK), 2-(ethylamino)-2-phenylcyclohexan-1-one (2-oxo-PCE), 2-(methylamino)-2-(2-methylphenyl)cyclohexan-1-one (2-MDCK), 2-(ethylamino)-2-(2-fluorophenyl)cyclohexan-1-one (2-FXE), 2-(2-bromophenyl)-2-(methylamino)cyclohexan-1-one (2-BDCK), and 2-(ethylamino)-2-(thiophen-2-yl)cyclohexan-1-one (tiletamine), and 2-(ethylamino)-2-(2-methylphenyl)cyclohexan-1-one (deoxymethoxetamine). According to the structures, these compounds can be seen as structural analogues of ketamine with benzene ring replaced by fluorine, bromine, methyl and methoxy groups, or with methyl group on the nitrogen atom replaced by ethyl group, or with benzene ring replaced by furan group. NENK, MXE, DCK and 2-FDCK have already been included in the annexes of the law in China, while 2-oxo-PCE, 2-MDCK, 2-FXE, 2-BDCK, and tiletamine have not been listed in the regulation. In order to evade the supervision of the law, new types of ketamine analogues have been continuously produced and offered for sale on the NPS market. These emerging new compounds have posed a great challenge to the testing and identification ability of forensic science laboratories around the world. The knowledge of MS fragmentation pathway characteristics of known structure NPS is essential for the structure elucidation of new types of NPS. In order to investigate the mass fragmentation characteristics of ketamine analogues, NENK, MXE, DCK, 2-FDCK, 2-oxo-PCE, 2-MDCK, 2-FXE, 2-BDCK, and tiletamine were analyzed using gas chromatography-Orbitrap mass spectrometry (GC-Orbitrap-MS) and ultra-high performance liquid chromatography-quadrupole time of flight-mass spectrometry (UPLC-QTOF-MS). High-resolution mass spectra were obtained by electron impact (EI) and electrospray ionization collision-induced dissociation (ESI-CID), the structures and fragmentation pathways of main ions were deduced. The product ions of ketamine analogues were mainly formed by the loss of CO, C2H5·, C3H7·, C4H9·, C5H11·/C6H13· in EI mode, and were mainly formed by the loss of H2O, CH3NH2/C2H5NH2, CO, C4H6, C2H4O in ESI-CID mode. The ketamine analogues distinguishing features were summarized by investigating the high-resolution mass spectrometric characteristics, which can provide a reference for the identification of new ketamine analogues with similar chemical structures.

Objective: This study aimed to detect the quality of wheat flour quickly and non-destructively. Methods: The online detection system for wheat flour quality was built in the experiment, which mainly includes the flowing four parts: micro near-infrared spectrometer integrated device, production line adjustable speed simulation device, spectrum online acquisition and control software and online modeling and analysis software. Different modeling algorithms were used to establish quantitative analysis models for moisture, ash and gluten, and the robustness of the online quantitative analysis model was optimized. The influence of different experimental conditions on the modeling results was analyzed. Results: Partial least squares regression （PLSR） algorithm is superior to multiple linear regression （MLR） and principal component regression （PCR） algorithm for quantitative analysis of moisture, ash and gluten. The best modeling effect was obtained by using quartz glass to collect wheat flour samples online, and the best ratio of 15 speed/integration time was 6 000 ms. Conclusion: The wheat flour quality online detection system based on near-infrared spectrum analysis technology realize the nondestructive and rapid online detection of wheat flour quality.

Molten salt-based nanofluid is a thermal storage and heat transfer medium for concentrated solar thermal power plants formed by adding nanoparticles to molten salt, which can enhance the thermal performance of molten salt. However, the nanoparticles tend to aggregate in nanofluids, causing changes in thermal properties. In this work, molecular dynamics simulations were used to study the effect of morphological characteristics of aggregates on the thermal conductivity and specific heat capacity of molten salt-based nanofluids. The results show that the aggregated nanoparticles cause a greater increase in thermal conductivity and specific heat capacity than dispersed nanoparticles. Additionally, the increase in fractal dimension leads to thermal conductivity reduction, while there is no clear correlation between the fractal dimension and specific heat capacity. New insights into the thermal properties of aggregated nanofluids are provided by analyzing the contribution of material components, heat flux fluctuation modes, and energy compositions. It is found that the thermal conductivity of aggregated nanofluids is mainly dominated by the base liquid and collision term. However, the specific heat is not related to the variation in the contribution of different energy compositions. Moreover, compared to the dispersed nanofluid, the increased specific heat capacity of aggregated nanofluids is attributed to the thicker semi-solid layer. This study provides guidance for the design and control of the thermal properties of molten salt-based nanofluids.

Bulblet initiation, including adventitious bud initiation and bulblet formation, is a crucial process for lily and other bulbous flowers that are commercially propagated by vegetative means. Here, by a hybrid strategy combining Pacific Biosciences (PacBio) full-length sequencing and Illumina RNA sequencing (RNA-seq), high-quality transcripts of L. brownii (Lb) and its variety, L. brownii var. giganteum (Lbg), during in vitro bulblet initiation were obtained. A total of 53,576 and 65,050 high-quality non-redundant full-length transcripts of Lbg and Lb were generated, respectively. Morphological observation showed that Lbg possessed a stronger capacity to generate bulblets in vitro than Lb, and 1 mg L−1 2,4-dichlorophenoxyacetic acid (2,4-D) significantly increased bulblet regeneration rate in two lilies. Screening of differentially expressed transcripts (DETs) between different stages and Mfuzz analysis showed 0 DAT to 1 DAT was the crucial stage with the most complex transcriptional change, with carbohydrate metabolism pathway was significantly enriched. In addition, 6,218 and 8,965 DETs were screened between the 2,4-D-treated group and the control group in Lbg and Lb, respectively. 2,4-D application had evident effects on the expression of genes involved in auxin signaling pathway, such as TIRs, ARFs, Aux/IAAs, GH3s and SAURs. Then, we compared the expression profiles of crucial genes of carbohydrate metabolism between different stages and different treatments. SUSs, SUTs, TPSs, AGPLs, GBSSs and SSs showed significant responses during bulblet initiation. The expression of CWINs, SUTs and SWEETs were significantly upregulated by 2,4-D in two lilies. In addition, 2,4-D increased the expression of starch degradation genes (AMYs and BAMs) and inhibited starch synthesis genes (AGPLs, GBSSs and SSs). SBEs were significantly upregulated in Lbg but not in Lb. Significant co-expression was showed between genes involved in carbohydrate metabolism and auxin signaling, together with transcription factors such as bHLHs, MYBs, ERFs and C3Hs. This study indicates the coordinate regulation of bulblet initiation by carbohydrate metabolism and auxin signaling, serving as a basis for further studies on the molecular mechanism of bulblet initiation in lily and other bulbous flowers.