ABSTRACT
This work is devoted to the applications of the multiple linear regression (MLR), multilayer perceptron neural network (MLP NN) and projection pursuit regression (PPR) to quantitative structure-property relationship analysis of bioconcentration factors (BCFs) of pesticides tested on Bluegill (Lepomis macrochirus). Molecular descriptors of a total of 107 pesticides were calculated with the DRAGON Software and selected by inverse enhanced replacement method. Based on the selected DRAGON descriptors, a linear model was built by MLR, nonlinear models were developed using MLP NN and PPR. The robustness of the obtained models was assessed by cross-validation and external validation using test set. Outliers were also examined and deleted to improve predictive power. Comparative results revealed that PPR achieved the most accurate predictions. This study offers useful models and information for BCF prediction, risk assessment, and pesticide formulation.
Subject(s)
Fishes/metabolism , Nonlinear Dynamics , Pesticides/metabolism , Software , Animals , Linear Models , Pesticides/chemistry , Quantitative Structure-Activity Relationship , Reproducibility of ResultsABSTRACT
Octanol/water (K(OW)) and octanol/air (K(OA)) partition coefficients are two important physicochemical properties of organic substances. In current practice, K(OW) and K(OA) values of some polychlorinated biphenyls (PCBs) are measured using generator column method. Quantitative structure-property relationship (QSPR) models can serve as a valuable alternative method of replacing or reducing experimental steps in the determination of K(OW) and K(OA). In this paper, two different methods, i.e., multiple linear regression based on dragon descriptors and hologram quantitative structure-activity relationship, were used to predict generator-column-derived log K(OW) and log K(OA) values of PCBs. The predictive ability of the developed models was validated using a test set, and the performances of all generated models were compared with those of three previously reported models. All results indicated that the proposed models were robust and satisfactory and can thus be used as alternative models for the rapid assessment of the K(OW) and K(OA) of PCBs.
Subject(s)
Air , Environmental Pollutants/chemistry , Models, Chemical , Octanols/chemistry , Polychlorinated Biphenyls/chemistry , Water/chemistry , Linear Models , Quantitative Structure-Activity RelationshipABSTRACT
An attractive method of generating second-order data was developed by a dropping technique to generate pH gradient simultaneously coupled with diode-array spectrophotometer scanning. A homemade apparatus designed for the pH gradient. The method and the homemade apparatus were used to simultaneously determine malachite green (MG) and crystal violet (CV) in water samples. The absorbance-pH second-order data of MG or CV were obtained from the spectra of MG or CV in a series of pH values of HCl-KCl solution. The second-order data of mixtures containing MG and CV that coexisted with interferents were analyzed using multidimensional partial least-squares with residual bilinearization. The method and homemade apparatus were used to simultaneously determine MG and CV in fish farming water samples and in river ones with satisfactory results. The presented method and the homemade apparatus could serve as an alternative tool to handle some analysis problems.
Subject(s)
Chemistry Techniques, Analytical/instrumentation , Gentian Violet/isolation & purification , Proton-Motive Force , Rosaniline Dyes/isolation & purification , Water/analysis , Animals , Aquaculture/methods , Chemistry Techniques, Analytical/methods , Fishes , Gentian Violet/analysis , Hydrogen-Ion Concentration , Rivers/chemistry , Rosaniline Dyes/analysis , Water/chemistry , Water Pollution, Chemical/analysisABSTRACT
OBJECTIVES: Minichromosome maintenance 8 (MCM8) is identified as an initiating helicase involved in DNA elongation and involved in cancer. However, little information is available for the role of MCM8 on chronic myelogenous leukemia (CML). We aimed to explore the expression and effect of MCM8 on CML. METHODS: Peripheral blood mononuclear cells (PBMC) and bone marrow mononuclear cells (BMMC) were prepared from six patients with CML and three healthy individuals. The mRNA levels of MCM8 were determined and compared. The expression of MCM8 was silenced by small interfering RNA (siRNA) approach in human CML cell line K562. After transfection with MCM8 siRNA, cell viability and apoptotic rate were analyzed, as well as the protein expression levels of Caspase-3 and B-cell lymphoma (Bcl)-xL. RESULTS: Relative mRNA levels of MCM8 were both significantly higher in PBMC and BMMC from CML patients than those in healthy individuals (P < 0.05). The cell viability was significantly reduced while the apoptotic rate was statistically increased by knockdown of MCM8 compared to control group or the scramble siRNA group (both P < 0.05). Moreover, the protein expression levels of Caspase-3 were significantly increased (P < 0.05), and while the levels of Bcl-xL were statistically reduced (P < 0.05) compared to the control group or the scramble siRNA group. CONCLUSION: MCM8 plays a significant role in CML, and knockdown of MCM8 might be a potentially targeted therapy for CML.
