Thermogravimetric and spectroscopic analyses along with the kinetic modeling of the pyrolysis of phosphate tailings.

The present study aimed to understand the pyrolysis characteristics of phosphorus tailings and promote the resource utilization of phosphorus tailings. Thermogravimetry was combined with Fourier transform infrared spectroscopy-Raman spectroscopy-mass spectrometry (TG-FTIR-RS-MS) and kinetic models to investigate the possible reaction mechanisms during the pyrolysis of phosphorus tailings and the changes in the release characteristics of pyrolysis volatiles. The results showed that the pyrolysis process occurred in three different stages. First, small amounts of adsorbed water were removed, and organic matter in the tailings was decomposed. Second, CaMg(CO3)2 underwent thermal decomposition to produce CaCO3, MgO, and CO2. Third, CaCO3 further decomposed into CaO and CO2. Similarly, the pyrolysis kinetics were divided into three intervals based on the differences in their activation energy values. The pyrolysis reaction mechanism functions were two-dimensional diffusion (Valensi model), nucleation and growth (Avrami-Erofeev, n = 1/2), and nucleation and growth (Avrami-Erofeev, n = 1/4). The gases released during the pyrolysis of phosphate tailings were mainly CO2, F2, and HF.

Novel Utilization of Terminators in the Design of Biologically Adjustable Synthetic Filters.

Terminators, which signal the end of transcription processes, are typically placed behind the last coding sequence of an operon to prevent interference between transcript units in most biologically synthetic systems. Here, we seek to extend the usability of terminators in genetic system design by using terminators as regulatory genetic parts. Terminators with different impacts on their upstream and downstream genes are characterized in detail via dynamic modeling to predict the behavior of the overall genetic system. Some nonlinear effects of terminators observed in our terminator measurements potentially facilitate regulation of gene expression. Through dynamic modeling in silico, we find that such genetic systems may behave like genetic filters. In agreement with the simulations, we successfully implement genetic high-pass and bandpass filters in vivo, demonstrating the potential of using terminators as regulatory parts. The genetic bandpass filter in this work is implemented through the interdependence between genetic parts, in which the termination efficiency of a terminator varies with the strength of the upstream promoter. This design strategy for a bandpass filter requires fewer base pairs than the conventional strategy of concatenating high-pass and low-pass filters. Our results show that this novel utilization of terminators as regulatory parts may provide a new perspective for efficient design of genetic circuits. We believe that further exploration of the complicated dynamics of terminators is important in the development of synthetic biology.

Association of plasma total and high-molecular-weight adiponectin with risk of colorectal cancer: an observational study in Chinese male.

The research is to investigate the association between plasma concentrations of total and high-molecular-weight (HMW) adiponectin and risk of early and advanced colorectal cancer. One hundred and sixty-five male colorectal cancer patients and one hundred and two controls were enrolled; based on the T factor of the TNM system, intraepithelial carcinoma and submucosally invasive carcinoma were defined as early cancer, and invasion into the muscularis propria or deeper was defined as advanced cancer. The plasma levels of glucose, fasting insulin, total cholesterol, triglyceride, and total and HMW adiponectin levels were measured. Each factor level was designated as low or high, and the risk of cancer was estimated by univariate and multivariate logistic regression analyses. In the patients with early cancer, high waist/hip ratio (WHR), high fasting insulin, high HOMA model insulin resistance index (HOMA-IR), low total adiponectin and HMW adiponectin were all associated with a significant increase in the odds ratio (OR) by univariate analysis. In multivariate analysis, WHR, HOMA-IR, total adiponectin and HMW adiponectin were all related to increased cancer risk. However, in the patients with advanced cancer, only low HMW adiponectin was associated with a significant increase in the OR by univariate analysis. In multivariate analysis, a low HMW adiponectin level was still related to increased cancer risk, with an adjusted OR of 3.971 (P = 0.036). In conclusion, a decreased level of adiponectin was a strong risk factor not only for early colorectal cancer but also for advanced colorectal in Chinese male patients. HMW adiponectin might be more closely associated with colorectal cancer risk than total adiponectin.