Bio-Engineering High Performance Microbial Strains for MEOR

The main objectives of this three-year research project are: (1) to employ the latest advances in genetics and bioengineering, especially Directed Protein Evolution technology, to improve the effectiveness of the microbial enhanced oil recovery (MEOR) process. (2) to improve the surfactant activity and the thermal stability of bio-surfactant systems for MEOR; and (3) to develop improved laboratory methods and tools that screen quickly candidate bio-systems for EOR. Biosurfactants have been receiving increasing attention as Enhanced Oil Recovery (EOR) agents because of their unique properties (i.e., mild production conditions, lower toxicity, and higher biodegradability) compared to their synthetic chemical counterparts. Rhamnolipid as a potent natural biosurfactant has a wide range of potential applications, including EOR and bioremediation. During the three-year of the project period, we have successfully cloned the genes involved in the rhamnolipid bio-synthesis. And by using the Transposon containing Rhamnosyltransferase gene rhlAB, we engineered the new mutant strains P. aeruginosa PEER02 and E. coli TnERAB so they can produce rhamnolipid biosurfactans. We were able to produce rhamnolipds in both P. aeroginosa PAO1-RhlA- strain and P. fluorescens ATCC15453 strain, with the increase of 55 to 175 fold in rhamnolipid production comparing with wild type bacteria strain. We have also completed the first round direct evolution studies using Error-prone PCR technique and have constructed the library of RhlAB-containing Transposon to express mutant gene in heterologous hosts. Several methods, such as colorimetric agar plate assay, colorimetric spectrophotometer assay, bioactive assay and oil spreading assay have been established to detect and screen rhamnolipid production. Our engineered P. aeruginosa PEER02 strain can produce rhamnolipids with different carbon sources as substrate. Interfacial tension analysis (IFT) showed that different rhamnolipids from different substrates gave different performance. Those rhamnolipids with plant oil as substrate showed as low an IFT as 0.05mN/m in the buffer solution with pH5.0 and 2% NaCl. Core flooding tests showed that rhamnolipids produced by our engineered bacteria are effective agents for EOR. At 250ppm rhamnolipid concentration from P. aeruginosa PEER02, 42% of the remaining oil after waterflood was recovered. These results were therefore significant towards considering the exploration of the studied rhamnolipids as EOR agents

Gold nanoparticles on hydrotalcites as efficient catalysts for oxidant-free dehydrogenation of alcohols

Hydrotalcite-supported gold nanoparticles with sizes of less than 5 nm are highly efficient and reusable catalysts for the oxidant-free dehydrogenation of alcohols to carbonyl compounds and hydrogen.NSFC [20625310, 20773099, 20873110]; National Basic Research Program of China [2010CB732303, 2005CB221408]; Key Scientific Project of Fujian Province of China [2009HZ0002-1

Exploring psychological nursing competency training program for nurses: A scoping review

The review aims to integrate the psychological nursing competencies training programme for nurses

A New Optimized Runge-Kutta Pair for the Numerical Solution of the Radial Schrödinger Equation

A new embedded pair of explicit modified Runge-Kutta (RK) methods for the numerical integration of the radial Schrödinger equation is presented. The two RK methods in the pair have algebraic orders five and four, respectively. The two methods of the embedded pair are derived by nullifying the phase lag, the first derivative of the phase lag of the fifth-order method, and the phase lag of the fourth-order method. Nu merical experiments show the efficiency and robustness of our new methods compared with some well-known integrators in the literature

Entanglement generation under feedback control in dispersive regime

The entanglement generation in a system of two atoms dispersively coupled to a damped cavity mode and driven by a classical field is investigated by using the quantum-jump-based feedback control. We demonstrate that the entanglement of the two atoms can be significantly enhanced and a steady state of antisymmetric Bell state can be obtained. We focus on the role of classical driving, and verify that the laser driving results in a global steady state which can be reached in the whole atomic subspace, but it can only be reached from some special initial states without laser driving. Therefore the system with classical driving is more robust against spontaneous emission and non-unit detection efficiency. Numerical results demonstrate that the maximal entanglement can be obtained for a wide range of parameters

Enhanced Hydrogen Evolution Performance of Carbon Nitride Using Transition Metal and Boron Co‐Dopants

Density functional theory calculations are used to study the effect of several metal dopants (M = Ag, Cd, Co, Cu, Fe, Ni, Pt, Sc, Ti, and Zn) and metal–boron co‐dopants on the structure and catalytic property of g‐C3N4 2D monolayer. Using transition metals and boron (TM–B) as co‐dopants not only keeps the 2D structure stability of g‐C3N4 monolayer, but also alters the catalytic performance of the structures. The co‐doping of B in TM (TM = Pt, Zn, Cd, Ti, and Sc)‐doped g‐C3N4 leads to a significant increase in the hydrogen adsorption energy because hydrogen binding site changes from N to C. For TM–B (TM = Fe, Co, and Ni) co‐doped g‐C3N4, the hydrogen adsorption energy has no obvious change since the hydrogen binding site remains on C atom near the doped TM. However, the co‐doping of B in TM‐ (TM = Cu and Ag) doped g‐C3N4 leads to a significant reduction of hydrogen adsorption energy, making them good candidates for hydrogen evolution reaction. This study provides theoretical guidance for the experimental synthesis of TM–B co‐doped g‐C3N4 and paves a way for the design of a widely applicable non‐noble catalyst

Synergistic Effect of Graphene Oxide and Mesoporous Structure on Flame Retardancy of Nature Rubber/IFR Composites

Aiming to improve the flame retardancy performance of natural rubber (NR), we developed a novel flame retardant synergistic agent through grafting of MCM-41 to graphene oxide (GO), named as GO-NH-MCM-41, as an assistant to intumescent flame retardants (IFR). The flame retardancy of NR/IFR/GO-NH-MCM-41 composites was evaluated by limited oxygen index (LOI), UL-94, and cone calorimeter test. The LOI value of NR/IFR/GO-NH-MCM-41 reached 26.3%; the UL-94 ratings improved to a V-0 rating. Moreover, the addition of GO-NH-MCM-41 decreased the peak heat release rate (PHRR) and the total heat release (THR) of the natural rubber composites. Furthermore, the addition of GO-NH-MCM-41 increased the thickness of char residue. The images of SEM indicated the char residue was more compact and continuous. The degradation of GO-NH-MCM-41-based NR composites was completed with a mass loss of 35.57% at 600 °C. The tensile strength and the elongation at break of the NR/IFR/GO-NH-MCM-41 composites were 13.9 MPa and 496.7%, respectively. The results of the rubber process analyzer (RPA) reached the maximum value, probably due to a better network of fillers in the matrix

Synthesis of a Carrageenan–Iron Complex and Its Effect on Flame Retardancy and Smoke Suppression for Waterborne Epoxy

A k-carrageenan–iron complex (KC–Fe) was synthesized by complexation between degraded KC and FeCl3. Furthermore, KC–Fe and ammonium polyphosphate (APP) were simultaneously added into waterborne epoxy (EP) to improve its flame retardancy and smoke suppression performance. The structure and properties of KC–Fe were assessed using Fourier transform infrared spectroscopy (FTIR), ultraviolet (UV) spectroscopy, thermo gravimetric analysis (TGA), and X-ray powder diffraction analysis (XRD). The analysis showed that KC–Fe was successfully synthesized and exhibited good thermal properties with a 49% char residue at 800 °C. The enhanced flame retardancy and smoke suppression performance of waterborne epoxy were evaluated using a limiting oxygen index (LOI) and UL-94. Moreover, the flame retardancy of waterborne epoxy coated on a steel plate was also investigated using cone calorimetry. The results showed that the flame-retardant waterborne epoxy blend exhibited the best flame retardancy when the mass ratio of APP and KC–Fe was 2:1. The total heat release (THR) and total smoke production (TSP) was decreased by 44% and 45%, respectively, which indicated good fire safety performance and smoke suppression properties. Analysis of the residual char using FTIR, SEM, and elemental analysis (EDS) indicated that the action of KC–Fe was promoted by the presence of APP. The formation of a dense thermal stable char layer from an intumescent coating was essential to protect the underlying materials