Determination of total alkaloid in tobacco by a safe and improved method based on KSCN

In this paper,an analytical method based on a chemical reaction between KSCN and sodium dichloroisocyanurate-dihydrate in a buffer system was applied to quantify the total alkaloid in tobacco.The proposed method replaced the No.35 Recommended Method of CORESTA(CRM 35)with the advantage that this method is safer compared to the CRM35 which uses KCN,a highly toxic chemical.In addition,compared to the current national standard method YC/T 468一2013,the buffer solution preparation was optimized to improve the detection efficiency.The validation results indicated that the new method met the test requirements,and the results were consistent with the ones obtained from the CORESTA CRM 35 and the YC/T 468一2013 methods.

Improved Isolation Forest Algorithm for Anomaly Test Data Detection

The cigarette detection data contains a large amount of true sample data and a small amount of false sample data. The false sample data is regarded as abnormal data, and anomaly detection is performed to realize the identification of real and fake cigarettes. Binary particle swarm optimization algorithm is used to improve the isolation forest construction process, and isolation trees with high precision and large differences are selected, which improves the accuracy and efficiency of the algorithm. The distance between the obtained anomaly score and the clustering center of the k-means algorithm is used as the threshold for anomaly judgment. The experimental results show that the accuracy of the BPSO-iForest algorithm is improved compared with the standard iForest algorithm. The experimental results of multiple brand samples also show that the method in this paper can accurately use the detection data for authenticity identification.

Nicotine Addiction Models and Evaluation of Animal Behavior

Nicotine is one of the most widely concerning components of cigarette smoke.Long-term intake of nicotine can lead to nicotine dependence that affects higher brain functions,which may involve anxiety,learning and memory impairments,and abnormal decision-making.To facilitate analyzing the molecular mechanisms of nicotine dependence,it is common to establish rodent nicotine dependence models to better understand the physiological changes.This paper summarizes and evaluates the application of animal behavior evaluation experiments in nicotine-dependent animal models,in order to provide a reliable reference for researchers to establish rodent nicotine-dependent models for evaluation.

A rapid protein sample preparation method based on organic-aqueous microwave irradiation technique

Fast and efficient sample preparation methods are a prerequisite for protein identification in bottom-up proteomics. Here, an innovative microwave irradiation sample preparation method was developed based on an optimized organic-aqueous solvent system for protein identification. Specifically, protein solutions containing high-concentration acetonitrile were subjected to 5 min microwave irradiation. After cooling down, trypsin was added and the digestion was performed with 30 s microwave irradiation, and the resulting peptides were analyzed by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry(MALDI-TOF MS). A shortened processing time of only 5.5 min is needed with this method(more than 12 h is necessary in the traditional overnight protein sample preparation). Moreover, due to the absence of urea and other chaotropic reagents, the digests can be readily identified by MALDI-TOF MS. When an assessment of this method was performed by digesting a model protein BSA, 69% ± 3% sequence coverage corresponding to 47 ± 3 peptides was obtained, which shows better protein identification than that from the standard overnight protein sample preparation method(51% ± 2% sequence coverage and 23 ± 1 peptides). Another model protein α-casein was used for the analysis of protein phosphorylation with the newly developed method that yielded 4 phosphopeptides with 8 phosphorylation sites, whereas 3 phosphopeptides with 2 phosphorylation sites were obtained from the traditional overnight approach. Moreover, the organic-aqueous microwave irradiation method provides effective digestion for proteins down to fmol.