Multi-Scenario Validation and Assessment of a Particulate Matter Sensor Monitor Optimized by Machine Learning Methods.

OBJECTIVE: The aim was to evaluate and optimize the performance of sensor monitors in measuring PM2.5 and PM10 under typical emission scenarios both indoors and outdoors. METHOD: Parallel measurements and comparisons of PM2.5 and PM10 were carried out between sensor monitors and standard instruments in typical indoor (2 months) and outdoor environments (1 year) in Shanghai, respectively. The optimized validation model was determined by comparing six machining learning models, adjusting for meteorological and related factors. The intra- and inter-device variation, measurement accuracy, and stability of sensor monitors were calculated and compared before and after validation. RESULTS: Indoor particles were measured in a range of 0.8-370.7 µg/m3 and 1.9-465.2 µg/m3 for PM2.5 and PM10, respectively, while the outdoor ones were in the ranges of 1.0-211.0 µg/m3 and 0.0-493.0 µg/m3, correspondingly. Compared to machine learning models including multivariate linear model (ML), K-nearest neighbor model (KNN), support vector machine model (SVM), decision tree model (DT), and neural network model (MLP), the random forest (RF) model showed the best validation after adjusting for temperature, relative humidity (RH), PM2.5/PM10 ratios, and measurement time lengths (months) for both PM2.5 and PM10, in indoor (R2: 0.97 and 0.91, root-mean-square error (RMSE) of 1.91 µg/m3 and 4.56 µg/m3, respectively) and outdoor environments (R2: 0.90 and 0.80, RMSE of 5.61 µg/m3 and 17.54 µg/m3, respectively), respectively. CONCLUSIONS: Sensor monitors could provide reliable measurements of PM2.5 and PM10 with high accuracy and acceptable inter and intra-device consistency under typical indoor and outdoor scenarios after validation by RF model. Adjusting for both climate factors and the ratio of PM2.5/PM10 could improve the validation performance.

[Method for continuous measurement of personal exposure to fine particulate matter].

OBJECTIVE: To develop a new accurate method for continuous measurement of personal exposure to fine particulate matter( PM_(2. 5) ) by integrating the advantage of both light scattering and gravimetric method. METHODS: The PM_(2. 5) concentrations were measured by both light scattering and gravimetric method simultaneously. The ratio of time-weighted average concentrations from gravimetric method to the responding values from light scattering method was calculated as coefficient of correction and used to calibrate the real-time PM_(2. 5) concentrations from light scattering method. RESULTS: The limit of detections( LOD) for 3, 10, 30 and 60 min time-weighted average concentrations of PM_(2. 5) were 4. 6, 4. 0, 3. 9 and 3. 7 µg/m~3, respectively. The precision( relativestandard deviation, RSD) was from 2. 1% to 9. 5%. The 30 min time-weighted average concentrations from this method were highly related to the results from TEOM method which was considered as reference method( Pearson r = 0. 934, P < 0. 001, n = 233), and no significantly bias between these two methods was detected by paired t test( P =0. 957). Zero drift was detected for 3 out of 10 devices with drift values in the range of- 5-- 3 µg/m~3 in the experiment of continuous 24 h monitoring conducted in the lab. And zero shift was also investigated in 7. 5%( 31 /412) field monitoring events, but most of the values shifted were within the range of- 3- 3 µg/m~3. The direction and scale of zero shift were not influenced by PM_(2. 5) concentrations. CONCLUSION: The developed method in this study that combines the advantages of both light-scattering and gravimetric method is validated to measure real-time concentrations of personal exposure to PM_(2. 5) .

Abatement of the binding of human hexokinase II enzyme monomers by in-silico method with the design of inhibitory peptides.

The hexokinase II enzyme is bound to the (VDAC1) channel in the form of a dimer and prevents the release of cell death factors from mitochondria to the cytoplasm. Studies have shown that blocking the binding of hexokinase II enzyme to (VDAC1) led to the initiation of apoptosis in cancer cells. No peptide has been designed so far to inhibit hexokinase II. The aim of this study was to inhibit the dimerization of enzyme subunits in order to inhibition the formation of (VDAC1) and the hexokinase II complex. In this study, the molecular dynamics simulation of the enzyme in monomer and dimer states was investigated in terms of RMSF, RMSD and radius of gyration. The following process involves extracting and designing variable-length peptides from the interacting segments of enzyme monomers. Using molecular dynamics simulation, the stability of the peptide was determined in terms of RMSD. Molecular docking was used to investigate the interaction between the designed peptides. Finally, the inhibitory effect of peptides on subunit association was measured using dynamic light scattering (DLS) technique. Our results showed that the designed peptides, which mimic common amino acids in dimerization, interrupt the bona fide form of the enzyme subunits. The result of this study provides a new way to disrupt the assembly process and thereby decreased the function of the hexokinase II. Supplementary Information: The online version contains supplementary material available at 10.1007/s40203-024-00201-8.

Inversion method of particle size distribution of milk fat based on improved MPGA.

Milk fat's particle size and distribution not only affect product quality, but also have great impacts on food safety in the economy and society. Based on total light scattering method, this paper has studied the inversion method of particle size distribution under dependent mode condition by combining multi-population genetic algorithm (MPGA) with Tikhonov smooth function. It has minimized the influence from light-absorb medium to improve the inversion accuracy. The approach introduces Tikhonov smooth function and apparent optical parameters to build an objective fitness function and weaken the ill condition of the particle size inversion equation. It also introduces multi-population genetic algorithm to solve the premature convergence of genetic algorithms. The results show that the relative error of the milk fat simulation solution with a nominal diameter is -3.52%, which meets the national standard of ±8% and better than the relative error of -5.01% of the standard genetic algorithm. Thus, the improved MPGA can reconstruct particle size distribution, with a good reliability and stability.

Peculiarities of the formation and subsequent removal of the circulating immune complexes from the bloodstream during the process of digestion.

Background: Large protein aggregates, known as circulating immune complexes (CICs), are formed in biological fluids as a result of the development of the body's immune response to various provoking factors. The kinetic characteristics of the formation and removal of immune complexes (ICs), their physical parameters, the isotypic composition of immunoglobulins (Igs) and the antigenic component of the CICs may reflect certain aspects of certain pathological and metabolic processes taking place in humans and animals. The aim of this study is to assess the kinetic characteristics of the formation and removal of the CICs that form in blood after eating. We also analyze the changes in the isotypic composition of Igs of ICs that accompany this biological process in rodents and humans. Methods: We identified the CICs, which differed in size and class of Igs, using dynamic light scattering. To remove ICs from the plasma, we used immune-affinity sedimentation. Monoclonal antibodies for the Igs of different isotypes were added to the plasma samples to determine the isotypic composition of the ICs. Results: A large number of ICs were formed in the blood of rats and humans after eating (food CICs). In rats, food ICs are almost immediately filtered in the liver, without circulating in the bloodstream through the body. In humans, the level of food ICs in the blood increases for 3.5 h after ingestion, then within 7-8 h their gradual removal takes place. It was found that in the process of digestion in humans, the isotypic composition of Igs in the CICs changes and becomes more diverse. Conclusions: The molecular-cellular mechanisms of the formation and utilization of food CICs in humans and rodents do not match completely.

Specific features of immune complexes in patients with sarcoidosis and pulmonary tuberculosis.

Clinical and radiological features of tuberculosis and sarcoidosis are quite overlapping, and therefore, a diagnostic dilemma often persists. There are no commonly accepted criteria for the diagnosis of sarcoidosis due to the lack of data on the etiology of the disease. The exclusion of tuberculosis in every patient with suspected sarcoidosis is a mandatory stage of diagnosis, especially in countries with a high burden of tuberculosis. A prospective study was conducted with two groups of patients: group I (n = 50)-patients with pulmonary sarcoidosis established according to standard criteria; group II (n = 28)-patients with pulmonary tuberculosis with bacterial excretion. The control group (n = 24) was presented by healthy subjects. The examination complex included x-ray, bacteriological, immunological (Mantoux test with 2 TE, TB.SPOT test), and histological methods. All patients and healthy subjects were assessed for immune complexes with the use of the dynamic light scattering (DLS) method and adding of "healthy lung tissue extract" antigens and specific tuberculosis antigens ESAT-6 and SFP-10 in vitro. Significant differences were found in determining specific immune complexes in patients with pulmonary sarcoidosis and pulmonary tuberculosis. Registration of specific immune complex formation with "healthy lung tissue extract" in 100% cases may indicate the autoimmune nature of sarcoidosis. The absence of the immune complex formation in response to ESAT-6/SFP-10 antigens can be used for the differential diagnosis of two diseases. The diagnostic significance of the DLS method was 100% for sarcoidosis and 92.2% for tuberculosis. The data obtained in the study allows not only understanding the etiology of sarcoidosis, but also obtaining new criteria for the differential diagnosis of tuberculosis and pulmonary sarcoidosis.