Simulations of frustrated Ising Hamiltonians using quantum approximate optimization.

Novel magnetic materials are important for future technological advances. Theoretical and numerical calculations of ground-state properties are essential in understanding these materials, however, computational complexity limits conventional methods for studying these states. Here we investigate an alternative approach to preparing materials ground states using the quantum approximate optimization algorithm (QAOA) on near-term quantum computers. We study classical Ising spin models on unit cells of square, Shastry-Sutherland and triangular lattices, with varying field amplitudes and couplings in the material Hamiltonian. We find relationships between the theoretical QAOA success probability and the structure of the ground state, indicating that only a modest number of measurements ([Formula: see text]) are needed to find the ground state of our nine-spin Hamiltonians, even for parameters leading to frustrated magnetism. We further demonstrate the approach in calculations on a trapped-ion quantum computer and succeed in recovering each ground state of the Shastry-Sutherland unit cell with probabilities close to ideal theoretical values. The results demonstrate the viability of QAOA for materials ground state preparation in the frustrated Ising limit, giving important first steps towards larger sizes and more complex Hamiltonians where quantum computational advantage may prove essential in developing a systematic understanding of novel materials. This article is part of the theme issue 'Quantum annealing and computation: challenges and perspectives'.

Dynamic Asset Allocation with Expected Shortfall via Quantum Annealing.

Recent advances in quantum hardware offer new approaches to solve various optimization problems that can be computationally expensive when classical algorithms are employed. We propose a hybrid quantum-classical algorithm to solve a dynamic asset allocation problem where a target return and a target risk metric (expected shortfall) are specified. We propose an iterative algorithm that treats the target return as a constraint in a Markowitz portfolio optimization model, and dynamically adjusts the target return to satisfy the targeted expected shortfall. The Markowitz optimization is formulated as a Quadratic Unconstrained Binary Optimization (QUBO) problem. The use of the expected shortfall risk metric enables the modeling of extreme market events. We compare the results from D-Wave's 2000Q and Advantage quantum annealers using real-world financial data. Both quantum annealers are able to generate portfolios with more than 80% of the return of the classical optimal solutions, while satisfying the expected shortfall. We observe that experiments on assets with higher correlations tend to perform better, which may help to design practical quantum applications in the near term.

Adsorption of Cr(VI) from aqueous solutions using novel activated carbon spheres derived from glucose and sodium dodecylbenzene sulfonate.

Cr(VI) is a common wastewater pollutant. Various adsorbents including carbon-based materials are used for the removal of Cr(VI) owing to their high adsorption capacity. Chemical activation is an effective method to increase the specific surface area of adsorbents and, thus, further improve their adsorption capacity. However, research on the adsorption and removal of Cr(VI) from aqueous solutions by chemically activated carbon spheres is limited. Here, glucose and sodium dodecylbenzene sulfonate were used to produce carbon spheres (CSs) via hydrothermal synthesis. Activated carbon spheres (ACSs) were then derived using KOH. The adsorption of Cr(VI) in solution by CS and ACS was investigated through batch experiments. The results indicate that the specific surface area of the ACS was 1491.21 m2 g-1, which was much higher than that of the CS. The adsorption kinetics of the sorbent was consistent with the pseudo-second-order kinetic model and the adsorption isotherm followed the Langmuir model. This indicated that the adsorption process of the ACS with respect to Cr(VI) was mainly via single molecular layer adsorption and chemisorption. In a 200 mg L-1 Cr(VI) solution, the maximum amount of Cr(VI) adsorbed by the ACS was 230.15 mg g-1, and some of these adsorbed Cr(VI) were reduced to Cr(III). These results show that ACSs have strong potential for application in the removal of Cr(VI) from aqueous solutions.

The process of biotransformation can produce insect protein and promote the effective inactivation of heavy metals.

An experiment was performed to study the inactivation effect of aerobic composting on heavy metals in maggot, pig and chicken manures. After composting, Cu mainly occurred in the oxidizable (OXI) fraction with a percentage distribution above 54%. Zn and Cd mainly existed in the bioavailable factor (BF), which has strong activity, with percentage distributions greater than 88.3% and 82.7%, respectively. Cr and Pb mainly existed in the stable residual (RES) fraction with a percentage distribution of approximately 50%. The aerobic composting process had a clear inactivation effect on heavy metals. For maggot manure compost in particular, the inactivation effects of Cu, Cr, Zn, Cd, and Pb were very good throughout the composting process, and the inactivation effect of Pb reached 54.42%. In addition, the process of biotransformation by housefly maggots promoted the conversion of fulvic acid (FA) to humic acid (HA) in pig manure, and the final increase in HA/FA after maggot manure composting was the largest among the different types of manure and beneficial to the inactivation of heavy metals. Compounds containing -CH3 and -CH2 groups were reduced, and aromatic structures were enhanced. Moreover, a maggot yield equivalent to 13.2% of the fresh pig manure was achieved during the process of biotransformation. The correlation analysis results showed that moisture content was an important factor affecting the inactivation rates of heavy metals in the three manure composts. Our results highlight that the process of biotransformation by housefly maggots can promote composting maturity and the inactivation of heavy metals, and produce a large amount of insect protein, yielding beneficial ecological and economic benefits.

Synergistic antitumour effects of triptolide plus gemcitabine in bladder cancer.

BACKGROUND AND OBJECTIVE: Gemcitabine (GEM) effectively inhibits bladder cancer progression in the clinic, but novel combination treatments using multiple drugs are needed. MATERIALS AND METHODS: The bladder cancer cell lines EJ and UMUC3 were treated with triptolide (TPL) and/or GEM. Tumour cell viability and proliferation were measured using MTT and clonogenic assays, respectively. Flow cytometry and western blotting were used to detect the cell cycle phase, apoptosis, reactive oxygen species (ROS) and the levels of specific relevant proteins. The AKT/GSK3ß signalling pathway proteins were also measured by immunofluorescence and western blotting. RESULTS: The cytotoxicity of the GEM plus TPL combination treatment was stronger than that of GEM or TPL alone. In bladder cancer cell lines, GEM plus TPL induced cell cycle arrest at the G1 phase via suppression of CDK4, CDK6 and cyclins A1 and A2. Significantly increased apoptosis and increases in apoptosis-related proteins (caspase 8 and Bcl-xL) were observed in cells treated with GEM plus TPL. While ROS increased, certain ROS-related proteins (catalase and SOD2) clearly decreased in cells treated with a combination of GEM plus TPL. The AKT/GSK3ß signalling pathway was also inhibited more significantly in cells treated with the GEM plus TPL combination than in cells treated with either agent alone. CONCLUSION: The combination of GEM plus TPL showed significantly enhanced anticancer effects compared to those of GEM or TPL alone.