STAT5 Confers Lactogenic Properties in Breast Tumorigenesis and Restricts Metastatic Potential

Signal transducer and activator of transcription 5 (STAT5) promotes cell survival and instigates breast tumor formation, and in the normal breast it also drives alveolar differentiation and lactogenesis. However, whether STAT5 drives a differentiated phenotype in breast tumorigenesis and therefore impacts cancer spread and metastasis is unclear. We found in two genetically engineered mouse models of breast cancer that constitutively activated Stat5a (Stat5aca) caused precancerous mammary epithelial cells to become lactogenic and evolve into tumors with diminished potential to metastasize. We also showed that STAT5aca reduced the migratory and invasive ability of human breast cancer cell lines in vitro. Furthermore, we demonstrated that STAT5aca overexpression in human breast cancer cells lowered their metastatic burden in xenografted mice. Moreover, RPPA, Western blotting, and studies of ChIPseq data identified several EMT drivers regulated by STAT5. In addition, bioinformatic studies detected a correlation between STAT5 activity and better prognosis of breast cancer patients. Together, we conclude that STAT5 activation during mammary tumorigenesis specifies a tumor phenotype of lactogenic differentiation, suppresses EMT, and diminishes potential for subsequent metastasis

Co-delivery of siRNAs and anti-cancer drugs using layered double hydroxide nanoparticles

In this research we employed layered double hydroxide nanoparticles (LDHs) to simultaneously deliver an anticancer drug 5-fluorouracil (5-FU) and Allstars Cell Death siRNA (CD-siRNA) for effective cancer treatment. The strategy takes advantage of the LDH anion exchange capacity to intercalate 5-FU into its interlayer spacing and load siRNA on the surface of LDH nanoparticles. LDH nanoparticles have been previously demonstrated as an effective cellular delivery system for 5-FU and siRNA separately in various investigations. More excitedly, the combination of CD-siRNA and anticancer drug 5-FU with the same LDH particles significantly enhanced cytotoxicity to three cancer cell lines, e.g. MCF-7, U2OS and HCT-116, compared to the single treatment with either CD-siRNA or 5-FU. This enhancement is probably a result of coordinate mitochondrial damage process. Thus, the strategy to co-deliver siRNA and an anticancer drug by LDHs has great potential to overcome the drug resistance and enhance cancer treatment

Robust estimation of bacterial cell count from optical density

Optical density (OD) is widely used to estimate the density of cells in liquid culture, but cannot be compared between instruments without a standardized calibration protocol and is challenging to relate to actual cell count. We address this with an interlaboratory study comparing three simple, low-cost, and highly accessible OD calibration protocols across 244 laboratories, applied to eight strains of constitutive GFP-expressing E. coli. Based on our results, we recommend calibrating OD to estimated cell count using serial dilution of silica microspheres, which produces highly precise calibration (95.5% of residuals <1.2-fold), is easily assessed for quality control, also assesses instrument effective linear range, and can be combined with fluorescence calibration to obtain units of Molecules of Equivalent Fluorescein (MEFL) per cell, allowing direct comparison and data fusion with flow cytometry measurements: in our study, fluorescence per cell measurements showed only a 1.07-fold mean difference between plate reader and flow cytometry data

Charge effect on protein partitioning in aqueous two-phase systems

Protein partitioning in aqueous two-phase systems is strongly affected by the net charge of the protein, but a thermodynamic description of the charge effects has been hindered by conflicting results. Many of the difficulties may arise from failures to isolate electrochemical effects from other interactions of phase components;This work was targeted at characterizing the charge effects on protein partitioning in polymer-polymer aqueous two-phase systems by using two series of genetically-engineered charge modifications of bacteriophage T4 lysozyme produced in E. coli. The two series, one in the form of charged-fusion tails and the other in the form of charge-change point mutations, provided matching net charges but very different polarity. Partition coefficients of both series were obtained and interfacial potential differences of the phase systems were measured. Phase systems with different polymer concentrations, different salts and salt concentrations were investigated. T4 lysozymes with different surface charge display different partitioning behaviors in all the aqueous two-phase systems that were studied, which indicates the importance of electrostatic effect on protein partitioning. All the proteins have different partition coefficients in systems with different overall polymer concentrations because of different potential differences and different polymer-protein interactions between the two phases. T4 lysozyme fusion-tail mutants display different partitioning behavior in all the phase systems from those of point mutations with matching net charge. In the systems with the same overall polymer concentration, but different salts and salt concentrations, both salts and proteins have different distributions between the two phases;A model based on the virial expansion was established to describe the dependence of the protein partition coefficient on phase composition and potential difference. Multi-angle laser light scattering measurements were performed initially to determine the second virial coefficients between proteins and polymers in a phase solution to calculate the interaction parameter in the model. However, the prediction of the parameter from the second virial coefficients obtained from laser light scattering has been very difficult. Therefore, a study on the second virial coefficients of different T4 lysozyme mutants in solutions with different ionic strengths was performed. The values of the second virial coefficients obtained from laser light scattering measurements were compared to those calculated from McMillan-Mayer theory using estimates of the molecular interaction forces. The results from laser light scattering agreed with the theoretical calculations at higher but not lower ionic strengths. Comparison of the second virial coefficients between T4 lysozymes with different net charge or charge distribution reveals the effects of surface charge and dipole moment of the protein on electrostatic intermolecular interactions.</p

Comparison of the exergy efficiency of four power generation systems from methane using fuel cells

Exergy analyses are carried out on four different solid oxide fuel cell (SOFC) systems using methane as the original fuel, with focus on exergy flows, efficiency and destruction. The four processes are (1) CH4-SOFC, which is a CH4 directly fuelled SOFC system with a CO2 capture unit; (2) CH4-SOFC-CLC, in which the CH4-SOFC system is integrated with chemical looping combustion (CLC); (3) SMR-SOFC, i.e. a SOFC system using H2 (H2-SOFC) generated by steam methane reforming (SMR); (4) MC-SOFC-DCFC, which is a combined system of H2-SOFC and a direct carbon fuel cell (DCFC) where H2 and C are supplied by methane cracking (MC). Generally, the CH4-SOFC and CH4-SOFC-CLC processes which directly use CH4 as the fuel of cells have higher exergy efficiency. MC-SOFC-DCFC reaches an overall exergy efficiency of 71.4%, which is 17% higher than that of SMR-SOFC (54.4%) due to the higher exergy efficiency of MC than SMR. The effects of operating parameters on the performance of CH4-SOFC are also examined in detail. The results of this investigation demonstrate that the development of methane directly fuelled SOFC, decreasing its operating temperature and suitable capture of CO2 are the key technologies to improve the energy conversion efficiency of methane fuelled SOFC systems

Effects of Amorphous Poly Alpha Olefin (APAO) and Polyphosphoric Acid (PPA) on the Rheological Properties, Compatibility and Stability of Asphalt Binder

High production costs and poor storage stability have become important constraints in the manufacture of modified asphalt binder. To simplify the production process and reduce the production cost, amorphous poly alpha olefin (APAO) and polyphosphoric acid (PPA) were applied to prepare highly stable modified asphalt binder. The influence of APAO/PPA on the temperature sensitivity, rheological property, storage stability, compatibility and microstructure of neat binder were studied by rotational viscosity (RV), dynamic shear rheometer (DSR), bending beam rheometer (BBR) and Fourier transform infrared (FTIR) spectroscopy. The results show that the incorporation of APAO/PPA reduced the temperature sensitivity of neat binder. The combined effect of APAO/PPA contributed to the improvement in deformation resistance, which was evidenced by the increase in failure temperature and percent recovery. However, the compound modification of APAO/PPA decreased the binder’s low-temperature performance. APAO strengthened the fatigue resistance of the binder, while PPA reduced the anti-fatigue performance. Composite modified asphalt binder with superior storage stability could be prepared, which was confirmed by the desired Cole–Cole plots and fluorescence imaging. Furthermore, chemical and physical reactions occurred during the APAO/PPA modification process. Overall, 2 wt.% (weight percentage) APAO and 1.5 wt.% PPA are recommended for the production of modified asphalt binder with remarkable rheological performance and storage stability

Influence of Compound Modification of Oil Sands De-Oiled Asphalt and Polyphosphoric Acid on High- and Low-Temperature Performance of Styrene-Butadiene-Styrene-Modified Asphalt

Oil sands de-oiled asphalt (OSDOA) has become a bottleneck for refineries due to its enormous production and huge landfill costs. Applying OSDOA as a modifier is an effective way to reduce environmental pollution and disposal cost. In this study, the influences of OSDOA and polyphosphoric acid (PPA) compound modification on styrene-butadiene-styrene (SBS)-modified binder were investigated. The high-temperature rutting resistance, low-temperature anti-crack performance and fatigue resistance were obtained by dynamic shear rheometer (DSR) and bending beam rheometer (BBR) test. Storage stability and microstructure were also investigated by storage test and Fourier-transform infrared (FTIR) spectroscopy. The results demonstrated that the compound modification of OSDOA/PPA dramatically enhanced the deformation resistance of SBS-modified binder and reduced its low-temperature cracking resistance. The anti-fatigue performance was also decreased. Moreover, the combined effect of OSDOA and PPA could produce composite modified asphalt with excellent storage stability, which was verified by desirable fluorescence images. Furthermore, both physical and chemical interactions coexisted during the OSDOA/PPA compound modification process. Consequently, the optimal doses of OSDOA and PPA were determined to be 10 wt% and 1.0 wt%, considering of the balance between high- and low-temperature characteristics and storage stability of composite modified asphalt

Exergy analysis of methane cracking thermally coupled with chemical looping combustion for hydrogen production

This paper proposes a novel hydrogen production process by Methane Cracking thermally coupled with Chemical Looping Combustion (MC-CLC) which provides an advantage of inherent capture of CO2. The energy utilisation performance of the MC-CLC process is compared with that of conventional Methane Cracking with combusting CH4 (MC-CH4) and Methane Cracking with combusting H2 (MC-H2) using exergy analysis, with focus on exergy flows, destruction and efficiency. The three MC processes are simulated using Aspen Plus software with detailed heat integration. In these processes, the majority of the exergy destruction occurs in the combustors or CLC mostly due to the high irreversibility of combustion. The CO2 capture unit has the lowest exergy efficiency in the MC-CH4 process, leading to a lower overall exergy efficiency of the process. The combustor in the MC-H2 process has a much higher energy efficiency than that in the MC-CH4 process or the CLC in the MC-CLC process. Although the use of H2 as fuel decreases the H2 production rate, the MC-H2 process provides the advantage of an absence of CO2 generation, and stores more chemical exergy in the solid carbon which can be utilised appropriately. The MC-CLC process obtains the highest exergy efficiency among the three models and this is primarily due to the absence of a CO2 capture penalty and the CLC\u27s higher fuel utilization efficiency than the conventional combustion process