IntroductionParkinson’s disease (PD) is characterized by progressive dopaminergic neurodegeneration, neuroinflammation, and emerging evidence of gut microbiota dysbiosis. Although nicotine has been implicated in neuroprotection, whether its enantiomers exert stereoselective effects on the gut-brain axis remains unknown.MethodsWe systematically compared the effects of S-nicotine and R-nicotine in an MPTP-induced mouse model of PD. Motor function, nigrostriatal dopaminergic neuronal loss, neuroinflammatory responses, intestinal barrier integrity, and gut microbiota composition were assessed.ResultsBoth enantiomers ameliorated motor deficits, attenuated nigrostriatal dopaminergic neuronal loss, and suppressed neuroinflammatory responses, yet exhibited markedly different efficacy profiles. S-nicotine produced robust neuroprotection at a lower effective dose (1 mg/kg), associated with improved motor performance, reduced central and peripheral inflammation, preservation of intestinal barrier integrity, and coordinated remodeling of the gut microbiota characterized by enrichment of Akkermansiaceae (notably Akkermansia). In contrast, R-nicotine required a higher dose (3 mg/kg) to achieve comparable neuroprotection and induced weaker and more heterogeneous microbiota alterations. Correlation analyses further revealed that S-nicotine-associated enrichment of Akkermansia was closely linked to improvements in motor function, reduced inflammatory status, and enhanced intestinal integrity.DiscussionThese findings demonstrate pronounced stereoselective and dose-dependent effects of nicotine enantiomers on neuroimmune modulation and identify gut microbiota remodeling as a functionally relevant correlate of nicotine-mediated neuroprotection in PD. Our results highlight the therapeutic potential of targeting the microbiota-gut-brain axis through chiral interventions and support S-nicotine as a promising candidate for neuroprotective strategies in aging-related neurodegenerative disorders.

Based on microwave resonance technology, a microwave amplitude change signal acquisition device of an activated carbon filter rod is created, and noise reduction and baseline deduction of the microwave amplitude change signal is combined with Gaussian filtering and the penalty least squares algorithm to improve the efficiency and accuracy of the detected activated carbon content. At first, the filtering effects of different Gaussian window lengths are compared. Following that, four processing methods were used to correct the baseline of the signal spectrum, including asymmetric least squares, adaptive iteratively reweighted penalized least squares, asymmetric reweighted penalized least squares, and multi-constrained reweighted penalized least squares, the peak height, peak area, and half-peak width of the microwave amplitude change signals after baseline correction were obtained. The models developed using the partial least squares algorithm, neural networks, and support vector regression were then compared. Finally, the repeatability, accuracy, and sensitivity of the detection device were assessed. The results revealed that the best model for activated carbon weight was"peak area-activated carbon weight"with a model determination coefficient of 0.9924, an average absolute error of 0.7979 mg, and a relative standard deviation of 1.4962%. The maximum standard deviation of activated carbon weight repeatability was 1.85 mg, the minimum absolute deviation for activated carbon weight testing was 0.03 mg, and the minimum relative deviation of activated carbon weight detection was 0.05%, resulting in a quick and effective method for quantifying analysis of activated carbon in an activated carbonfilter rod for tobacco.

Laryngeal cancer is a common head and neck malignant cancer type. However, effective biomarkers for diagnosis are lacking and pathogenesis is unclear. Lipidomics is a powerful tool for identifying biomarkers and explaining disease mechanisms. Hence, in this study, non-targeted lipidomics based on ultra-performance liquid chromatography–quadrupole time of flight–mass spectrometry (UHPLC-QTOF-MS) were applied to screen the differential lipid metabolites in serum and allowed for exploration of the remodeled lipid metabolism of laryngeal cancer, laryngeal benign tumor patients, and healthy crowds. Multivariate analysis and univariate analysis were combined to screen for differential lipid metabolites among the three groups. The results showed that, across a total of 57 lipid metabolic markers that were screened, the regulation of the lipid metabolism network occurred mainly in phosphatidylcholine (PC), lysophosphatidylcholine (LPC), and sphingomyelin (SM) metabolism. Of note, the concentration levels of sphingolipids 42:2 (SM 42:2) and sphingolipids 42:3 (SM 42:3) correlated with laryngeal cancer progression and were both significantly different among the three groups. Both of them could be considered as potential biomarkers for diagnosis and indicators for monitoring the progression of laryngeal cancer. From the perspective of lipidomics, this study not only revealed the regulatory changes in the lipid metabolism network, but also provided a new possibility for screening biomarkers in laryngeal cancer.

喉癌是一种常见的头颈部恶性肿瘤,但其具体的发病机制尚不明确,是少有的五年生存率呈现下降趋势的一类癌症.越来越多的研究表明,肿瘤微环境中细胞与基质成分的变化、免疫逃逸和代谢重编程等过程对癌症的发生发展具有重要的推动作用.了解喉癌微环境可以为喉癌的发病机制和早期诊断提供新思路,从而制定更好的治疗和预后策略.因此,该文结合喉癌的流行病学现状,对喉癌微环境的组成、在病情发生发展中的作用以及喉癌代谢重编程的具体特征进行了综述.

In order to detect the oxygen consumption during cigarette smoking, a detection system was developed by incorporating tunable diode laser absorption spectroscopy (TDLAS) technology coupled with a modified single port smoking machine. The results showed that within the oxygen concentration range of 2%-30%, the peak value of its secondary harmonic signal intensity presented good linearity (R2=0.999 1). The system showed higher detection precision (<3%) and less affected by temperature, the puff-by-puff detection sensitivity was of 0.004 a.u/(0.058%); intra-day RSD (0.145%) and inter-day RSD (0.26%) were smaller. The puff-by-puff oxygen consumption of reference cigarette (3R4F) was determined, the results indicated that the oxygen consumption during smoking positively correlated to puff number. The developed detection system features simple structure, short detection time and high time resolution, and has good application prospects for researching cigarette's combustion state and its relationships with cigarette smoke.

基于可调谐二极管激光吸收光谱(TDLAS)技术、波长调制技术和二次谐波检测方法,利用CO和CO2在1579 nm处的泛频吸收特征,结合改造后的单孔道吸烟机,建立了卷烟主流烟气逐口检测系统.实验结果表明:气体浓度与其二次谐波强度的线性度较好,系统响应速度较快,精度能达到检测要求,逐口检测稳定性、重复性和灵敏度均较好.同类型卷烟主流烟气中CO、CO2的逐口释放量除第1口之外,均呈递增趋势,CO2的逐口释放量和递增速率均比CO的大,且不同类型的卷烟遵循相同的规律.所建系统具有检测速度快、时间分辨率高、结构简单等优势,在卷烟烟气有害物质的快速检测领域具有较好的应用前景.

A comprehensive analytical method based on gas chromatography-thermal energy analyzer was developed for the determination of NDELA in cosmetics. NDELA were extracted with water from cosmetic samples under ultrasonic. After high speed freeze centrifugation, the upper aqueous phase was evaporated to dryness by nitrogen. The residue dissolved in mixed solution and was cleaned up. Then the acetone eluent was filtered by microporous membrane to store in sample vial. Qualitative and quantitative analysis was carried out under thermal energy analyzer after the chromatographic separation on a DB-624(30 m×0. 25 mm, 1. 4μm)capillary column. The limits of quantitation for NDELA were 20μg/kg and the recovery was from 87% to 105%. Parts of cosmetics were positive and the highest concentration reached 48 μg/kg. The method was suitable for determination of NDELA in cosmetics.

To eliminate the defects of inconvenience operation,puff-by-puff detection that can't be done online which caused by using non-dispersive infrared method to detect CO in cigarette mainstream smoke,a new online detection system using tunable diode laser absorption spectroscopy(TDLAS)technology is established based on LabVIEW.The system hardware mainly consists of a smoking machine for cigarette smoking and a TDLAS controller for CO detection.By processing the data acquired from the lock-in amplifier that housed in TDLAS controller,the concentration of CO in cigarette mainstream smoke is calculated.Thus the content of CO in each puff can also be calculated with definite volume.The result shows that the system can effectively detect the content of CO in cigarette mainstream smoke puff-by-puff and online with a stable and reliable operation.

Tunable diode laser absorption spectroscopy (TDLAS) technology combined with wavelength modulation spectroscopy (WMS) technology is an important technique for trace gas detection. Detected with the lock-in amplifier, the second harmonic signal obtained after demodulation is analyzed to get the gas absorption information. However, the second harmonic signal is affected by noise which reduces the accuracy and stability of the detection system. To improve the signal to noise ratio (SNR) of the TDLAS detection system, a denoising method based on Gabor transform is proposed for second harmonic signal noise reduction. Taking the CH4 absorption spectrum at 1 653.72 nm as an example, the effectiveness of the noise reduction method is verified through simulation and experiments. The simulation results show that the signal to noise ratio for the second harmonic signal of 0 dB can be improved 15.73 dB with Gabor transform-based denoising method. Experimental results show that with the Gabor transform-based denoising method, the linear correlation coefficient r can be as high as 0.996 59 between the second harmonic peak value and the CH4 concentration in the range of 0.001%~0.02%. At the same time, the detection accuracy and stability of the system have been improved significantly.

建立了化妆品中5种挥发性亚硝胺的气相色谱-热能分析仪联用(GC-TEA)同时分析测定方法.利用丙酮在超声条件下将5种挥发性亚硝胺从水溶性或脂溶性化妆品样品中萃取出来,经过高速冷冻离心后,用二氯甲烷分三次萃取提取上清液,收集上清液于底部加入无水硫酸钠试管中,水相在氮吹仪上浓缩后添加内标N-亚硝基二丙胺,再经微孔滤膜过滤到棕色色谱瓶进样检测.该方法能够有效地检测出化妆品中的5种挥发性亚硝胺,方法定量限为13.5～27μ g/kg,回收率为86.2％～95.4％,精密度为2.0％～6.5％.本方法杂质峰少,准确度、灵敏度高,线性范围宽,能够满足化妆品中5种挥发性亚硝胺的测定要求.

Rapid and real-time analysis of cigarette smoke is of great significance to study the puff-by-puff transfer rules in the suction process and to explore the relationship between smoking and health. By combining with the modified commercial smoking machine herein, cigarette smoke online analysis system was established based on the TDLAS technology. The puff-by-puff stability of this system was verified by simulated cigarette composed of a pocket containing CH4 (volume fraction of 0. 4), of which the second harmonic peaks are near 1. 39. Using this system, the concentration of CH4 in four different kinds of cigarettes was analyzed puff-by-puff by a semiconductor laser, of which center wavelength was at 1 653. 72 nm. The results showed that the CH4 concentration of cigarette smoke increased puff-by-puff. CH4 concentration in the flue-cured cigarette is obviously higher than that of blended cigarette by comparing the content of all and puff-by-puff concentration. The puff-by-puff concentration of flue-cured cigarette increased from 400 to 900 ppm, however, the puff-by-puff concentration of blended cigarette increased from 200 to 600 ppm. Simultaneously, there was significant difference between different kinds of the flue-cured. Comparing to traditional analysis methods, this system can effectively avoid the interference of other gases in the smoke cigarette as a result of its strong anti-interference. At the same time, it can finish analysis between suction interval without sample pretreatment. The technology has a good prospect in the on-line puff-by-puff analysis of cigarette smoke.

Mass flow control of gas with micro flow is an important component of chemiluminescence detection of nitrosamines,the accuracy of gas flow greatly affects the measurement results.In this paper,a gas flow controller which was suitable for micro flow control was set up with miniature solenoid proportional valve,flow sensor,digital control circuit and PID control algorithm.The driver circuit for proportional valve,signal processing circuit for flow sensor and microcontroller circuit were designed.Control algorithm has been optimized according to the characteristics of controlled object.According to testing results the accuracy was better than ±0.05ml/min(under standard conditions),setting time was less than 2s,nearly had no over shoot.The controller had a good performance of anti-interference because of the using of feedback control.It is easy to use,low cost effective and had some practical value.

A chemiluminescence devices for the nitrosamines gas chromatography was build,that can detected the concentration of the NO from the gas chromatography with devices as the gas chromatography detector,according to the concentration of the nitrosamines was in proportional to the NO concentration,then concentration of nitrosamines can be calculated.The some key design and how affected our system performance by the chamber pressure were investigated,and the best experimental parameters were confirmed.The NO standard gas with concentration of 4.2mg/kg was practically determined by the detection system,and linearity for the system was more than 0.98,and detection limitation was less than 1pg/s.The system can quickly and accurately detect trace NO,and the NO can be the chromatography detector for nitrosamines detect.